Patent Application
20220107008
Presently, synchronized clutch is used in transmissions to shift from one ratio to another ratio which involves a brief torque interruption affecting efficiency. This invention pertains to uninterrupted shifting in transmissions with the use of controlled rotation to achieve the desired profile for the input to output ratio over time, thereby eliminating synchronized clutch.
Controlled rotation is achieved using non-circular gears or Geneva pin and slot wheel mechanism with a customized path for the slot. All the non-circular gears and regular gears in this invention can be replaced with Geneva pin and wheel mechanism. Controlled rotation using non-circular gears or Geneva mechanism can be used to achieve multiple speed/infinitely variable transmission ratios and/or to transition from one transmission ratio to another. Multiple pins and multiple slots are used and with an overlap of more than one pin achieving a portion of the same results simultaneously.
CVT using ratchet mechanism with scotch yoke mechanism, rack, and pinion and one way bearing 138 must use controlled rotation in order to have uniform rack movement.
Geneva pin wheel 96 and Geneva slot wheel 97 with a slot with a specific geometry/path can be used in place of non-circular gears or circular gears briefly overlapping with existing ratio and ramping up or down to reach the targeted ratio and then overlapping with the targeted ratio and disconnecting.
In the prior arts CN101737461A and WO2017190727A1, the operating plane is moved along with a single driven circular gear.
In prior art CN101737461A the input shaft and output shaft are placed at an angle, and not parallel. So, the “depth’ dimension depends on the sizes of the circular gears and could be large.
In prior art WO2017190727A1, the center-to-center distance changes with every shifting. So, this invention cannot be used in applications where the center-to-center distance is required to be constant.
In both prior arts the design has only one size gear for the driven gear. This limits the number of inputs to output combination. A steep increase or decrease of ratio is hard to achieve.
Another disadvantage for both the prior arts is that for all the driving gears there is a single driven gear which limits the range for the input-to-output ratio.
In prior art CN100400940C non-circular gears are used to bridge transition from one ratio to another by briefly overlapping the constant regions of the existing ratio to the targeted ratio of the transmission ratios for a smooth transition. The non-circular gear has regions of existing ratios and targeted ratio separated by ramp up and ramp down regions. The drawback is that these driving and driven non-circular gears must have exact number of teeth and the ratio of their pitch circle perimeters must be an integer or reciprocal of an integer in order to achieve repeatability. This reduces the duration of one or more regions and not suitable for high-speed application such as electric vehicles where the RPM is very high. The current invention uses non-circular gears with “bald” region in place of ramp up region or ramp down region to eliminate the need to have repeatability. The missing region is added to another set of non-circular gear pairs. These non-circular/circular gears are segmented and have the ability to axially move away/toward their operating planes to engage/disengage with each other without the need of a clutch/dog clutch. Thus, need for repeatability is eliminated here.
The current invention eliminates all the above disadvantages. The current invention also allows a smooth transition from one ratio to another ratio in an uninterrupted manner without the need for a synchronizer or clutch. The current invention also uses a Geneva mechanism, with custom path for the slot wheel, to replace circular or non-circular gear. Non-circular gears are an expensive option when compared to Geneva mechanism with custom path. By having a circular pin or optionally non-circular pins for the pin wheel 96 any slight variation in the desired input/output can be easily adjusted. Cam and pin can also be used in place of Geneva mechanism.
Today, several Continuously Variable Transmissions exist that use a belt and variable diameter pulleys that totally relay on friction between the belt and the pulley to transmit power, offering infinite input to output ratios. The pseudo continuously variable transmission in this disclosure does not fall under the category “Continuously” Variable Transmission since it has a discrete number of ratios rather than infinite ratios. Each of them uses multiple sprockets/gears on driving and the driven ends while only one sprocket/gear is active at both the ends at any given time. By swapping between larger and smaller sprocket/gears the input to output ratio is changed. When shifting from one ratio to another, the change is continuous and gradual. Hence the name Pseudo Continuously Variable Transmission.
The present invention relates to smooth uninterrupted synchronizing before shifting of gears. Geared bicycles today have multiple sprockets with different sizes placed coaxial and offset to one another and the Chain/Belt 139 is made to travel axially using a derailleur to align with a specific sprocket. Another way to achieve this will be to keep the Chain/Belt 139 in the same plane and instead move the sprockets of various sizes in and out of chains plane. The same idea can be extended to regular gears, pulleys, and cage pins. Spring loaded segments forming different full larger size gears including non-circular gears are moved in and out of operating plane to achieve several input to output ratios. Same concept can be applied to pulleys too. With gears, pulleys or sprockets, this idea can be applied not just for bicycle application but also to automotive and other applications.
In chain and sprocket application, since there is a tensioner involved, so, the shifting will be smoother. However, this will not be true for gears. The change would be abrupt. When used with a set of non-circular gears, this shifting can be achieved in an uninterrupted manner. This idea can be applied not just for bicycle application but also to automotive and other applications.
The infinitely variable transmission in this disclosure pertains to transmissions having variable ratios between input and output velocities. Specifically, it relates to all-gear transmissions whose velocity ratios may be changed continuously over a wide range of values ranging from zero to non-zero values, without depending on friction. This invention provides a design for UNIFORM and STEADY output, when the input is uniform and steady, with the ability to transmit high torque without depending on friction or friction factor. Many of the continuously variable transmissions that are in the market today are friction dependent and therefor lack the ability to transmit high torque. Those continuously variable transmissions, which are non-friction dependent do not have a uniform and steady output when the input is uniform and steady. The design that offers all is too complex and hard to mass produce. This design aids reduction in the overall size and can be economically mass produced. This design can be easily integrated into any system. This design is very versatile and can be used ranging from light duty to heavy duty applications. This design allows replacement of existing regular transmission, requiring very little modification. This design offers stationary and co-axial input and output.
In order to switch ratios in a transmission the input shaft and output shaft disconnect and connect to gears that are different in size. Technology today enables this by temporarily disconnecting the set of gears that are engaged and with the use of synchronizers switches to another set of gears. A CVT that uses a variable pulley and belt system enables this, however the efficiency is lower than that of a transmission that uses gears. Since variable pulley and belt CVTs are friction dependent, the torque transmitting capacity is limited. Use of multi-speed transmission eliminates this problem. However, it has limited number of ratios.
This invention provides a design for a multi-speed transmission that does not use synchronizers or clutches. It uses an additional set of non-circular gears and dog clutch 53 which are comparatively inexpensive than having synchronizers and clutches. So synchronized uninterrupted shifting of two speed makes it ideal for an electric car. Geneva pin wheel 96 and Geneva slot wheel 97 with a slot with a specific geometry/path can be used in place of non-circular gears or circular gears.
A major advantage in today's Continuously Variable Transmissions that use a belt and variable diameter pulleys is that there is no interruption during ratio changing. However, they rely on friction. The ratio change is continuous. This new invention also offers uninterrupted shifting during ratio changing, however, has a discrete number of gear ratios. So, the current invention does not fall under the category “Continuously” Variable Transmission since it has a discrete number of ratios rather than infinite ratios. In a regular transmission, multiple gears on driving and the driven ends are used, while only one gear is active at both the ends at any given time. By simultaneously activating a non-circular gear pair for a brief period while swapping between larger and smaller gears, the input to output ratio is changed uninterrupted. When shifting from one ratio to another, the change is continuous and gradual. Hence the name Pseudo Continuously Variable Transmission. These concepts and detailed working operation are explained in Detailed Description of the Invention section.
The U.S. Pat. No. 9,970,520 offers a steady input to output ratio and co-axial input and output shaft in a comparably smaller envelope than that of its prior art. This is achieved with a use of a set of non-circular gears using as few as three modules. The drawback is that it is hard to mass produce the desired non-circular gears and will add significant manufacturing cost. It is also difficult to accurately design the tooth profile to achieve a uniform input to output ratio.
The present invention uses a custom designed Geneva wheel mechanism to achieve uniform rack velocity during functional region and circular/non-circular gear for non-functional region. The portion of the region used by the Geneva wheel mechanism is also non-functional region which overlap with the non-functional region achieved by the circular/non-circular gears for smooth transition. It is also possible to use Geneva wheel mechanism for functional and non-functional region. However, it will be economical to use a partial circular gear for the non-functional region. The path of the Geneva slot engaging with the Geneva pin determines the shape of the functional or non-functional region.
In general, a Geneva wheel mechanism has straight slot and is commonly used in applications needing indexing. Using a commonly used Geneva wheel mechanism with straight slot will not achieve uniform rack movement in the functional region and these slots must have a specific shape to achieve uniform rack movement in the functional region.
For Geneva wheel mechanism with straight slots, it is not possible to use multiple pins working at the same time. Resulting angular velocity will not be identical for both pins to have uniform overlap.
This invention provides a design for a Pseudo Continuously Variable Transmission with multi-speed uninterrupted shifting from one ratio to another. This design has multiple pairs of gears for the different gear ratios. The transition from one ratio to the next is continuous and gradual and is achieved using one of the following:
This invention also discloses an infinitely variable transmission with uniform and steady output, when the input is uniform and steady, with the ability to transmit high torque without depending on friction or friction factor. It uses controlled rotation between driving and driven shafts to achieve this. This design allows replacement of existing regular transmission, requiring very little modification. This design offers stationary and co-axial input and output.
This design uses
All the gears in the component list can be replaced with a sprocket and chain system. The non-circular gear system can be replaced with a sprocket and chain system where at least one of the sprockets is non-circular.
I) Utilizing Gears and Sprockets (Circular and Non-Circular) to Achieve Multi-Speed Transmission with Uninterrupted Shifting (MSTUS) (
Here the shifting is achieved by swapping to the operating plane between larger and smaller gears for the different ratios and non-circular gears moving to operating plane or extending Geneva pin to the Geneva slot to transition between them.
Similarly, with driving and driven sets of gears, two smallest size full gears are placed co-planer at a fixed center to center distance. Segments forming full larger size gears are placed co-axial but offset to the full-size gears. These spring-loaded segments of larger gears can be moved in and out of operating plane to achieve several input-to-output ratios.
Similarly, Cage pins/Geneva pins also can be used in place of segments of sprockets/gears to work with cycloidal disk/Geneva wheel.
Also, when segmentation of the gears is not desired, smooth uninterrupted shifting of gears can also be achieved by mounting all the driving gears (along with non-circular gears) on one shaft, namely drive shaft, and all the driven gears (along with non-circular gears) placed freewheeling on another shaft, namely Driven Shaft 142. The non-circular gear pairs (driving and driven) have regions where two or more constant ratios are preceded and followed by acceleration and deceleration regions. The constant regions have the same ratios of the circular gear pairs. The ramp up and/or ramp down regions connect one ratio to the next smaller or next larger ratio, as appropriate. The Driven Shaft 142 is linked with appropriate driven gear(s). When shifting from one ratio to another ratio it is sequenced via the non-circular gear pair that has the ratio of the region of exiting ratio and the ratio that is transitioned to.
Achieving MSTUS with gears (
With driving and driven sets of several pairs of gears, two smallest size full gears are placed co-planer at a fixed center to center distance. Spring loaded segments forming full larger size gears are placed co-axial but offset to the full-size gears or base operating plane gears 150. These spring-loaded segments of larger gears can be moved in and out of operating plane to achieve several input to output ratios.
A pair of driving and driven gear/Gear Segments 151 are selected so that the center-to-center distance which is the sum of the radii of the driving and driven pairs is constant. If the driving or driven gear is to be changed from smaller to larger size, then the larger Gear Segments 151 are slipped into the operating plane for one gear, and the larger Gear Segments 151 are slipped out of the operating plane for the other gear so that two gears can mesh with each other. The offset planes of segments of gears of driving and driven sets are so placed so that the largest gears of both sets do not interfere with each other. This can be achieved by placing the segment of large gears are placed on either side of the gears are slipped in and out on a protrusion 154 of the base operating plane gear 150 using a roller 11 and gear segment guide 152, in the regions where driving and driven gears are not in contact 1003 and 1004. In order for the teeth of the driving and driven gears to mesh exactly, the gears may have to be rotated to a certain correct position. This can be achieved using rotationally fixed axially movable spiral ramp/cam 168 or position sensors with computer-controlled solenoids.
Similarly, for achieving with Geneva pin wheel 96 and slot wheel 97 OR non-circular pin gear mechanism (
Pins placed in a circular and also non-circular pattern on several circumferences are placed on Geneva wheel to mesh with several Geneva slot wheels 97, where matching Geneva slot wheels 97 are placed co-axial at an offset distance respective to their sizes. The pins are retracted and extended just to meet with the respective Geneva wheel from the side facing the smallest Geneva slot wheel 97. This is done to avoid interference of pins on larger circumference with larger Geneva slot wheel 97. The pins are extended only during when the pins are in contact with the slot in the region where the pin and wheel are in contact. When the pins are not in contact with the slot, the pins are retracted in that region. Also, the slot can ramp up when the pin and slot engagement region at the near end such that the pins are pushed out to the retracted position.
Also, when segmentation of the gears is not desired, new mechanisms that is patented, and existing technologies are shown in
The sequence of operation is as follows:
For upshift (
a) With the Driven Shaft 142 linked to the existing driven gear,
b) when the non-circular gear, which has the constant region of the existing ratio followed by ramp up region to the region of the next higher ratio, reaches and well within the active region the current circular gear's ratio of the non-circular gear ratio is also linked to the Driven Shaft 142.
c) Once both the speed of the non-circular gear and the current circular gear are synchronized the circular gear is disengaged from the Driven Shaft 142.
d) As the ratio of the non-circular gear passes through the ramp up region to the next higher ratio, the driven gear with the larger ratio is also engaged to the Driven Shaft 142. This can be achieved with a One-way bearing 5050 used at the driven gear of the larger ratio
e) When the ratio of the non-circular gear is synchronized with the active circular gears the Driven-Non-Circular-Gear is disengaged.
Similarly, for down shift (
a) With the Driven Shaft 142 linked to the existing driven gear,
b) when the non-circular gear, which has the constant region of the existing ratio followed by ramp down region to the region of the next lower ratio, reaches and well within the active region the current circular gear's ratio of the non-circular gear ratio is also linked to the Driven Shaft 142.
c) Once both the speed of the non-circular gear and the current circular gear are synchronized the circular gear is disengaged from the Driven Shaft 142.
d) As the ratio of the non-circular gear passes through the ramp down region to the next lower ratio, the driven gear with the larger ratio is also engaged to the Driven Shaft 142. This can be achieved with a One-way bearing 5050 used at the driven gear of the larger ratio e) When the ratio of the non-circular gears is synchronized with the active circular gears the Driven-Non-Circular-Gear is disengaged.
During normal operation when upshift or downshift are in action the Driving-Non-Circular-Gears are disengaged from the shaft it is mounted and remain stationary.
The engagement and disengagement can be achieved via a dog clutch or dry or wet clutch or any other suitable technology currently available in the industry
The non-circular gear pairs may have multiple constant regions with or without ramp (abrupt) ascending or descending
The non-circular gear pairs may have multiple constant regions ascending followed by ascending or descending and/or descending followed by ascending or descending in any desired movement path.
The non-circular gear pairs can be designed to have any desired movement function between driven to driving
The pair of noncircular gears can be sandwiched between circular gears. This will allow manual gear shifting possible without the need for a computer-controlled shifting.
In the above scenario one potential issue is that since the non-circular gears spin with the same angular velocity as the Driving shaft 144, the duration of each lower and higher region and the ramp region 1015 is short. So, it is not ideal for high-speed application. It is beneficial if the duration of each of these regions is increased. This can be achieved by a ‘Duration Extender Module’ 1001.
The Duration Extender Module 1001 has one or more pairs of speed reduction gears, a pair of non-circular gears, and one or more sets of pairs of Duration Extender Module driving gears 61 and Duration Extender Module (DEM) Driven Gears 165 arranged as shown in
Extension Module can be limited to the duration of ratio change sequence to eliminate vibration as shown in
The Driving Non-Circular Gear 143 is axially connected to the large driven gear of a pair of speed reduction gears. The smaller Driving-Circular-Gear of the speed reduction gears is rigidly mounted to the Driving shaft 144 and the larger driven gear of the speed reduction gears is axially connected to the Driving-Non-Circular-Gear with an ability to engage/disengage via a Linking Mechanism 153. This extends the duration of lower and higher regions and the ramp region 1015 of the non-circular gears. The Driven-Non-Circular-Gear is mounted on a parallel shaft or on the Driving shaft 144 on a bearing 138. Several circular Duration Extender Module Driving Gear 61s, axially connected to the Driven-Non-Circular-Gear, are meshed to the corresponding circular Duration Extender Module Driven Gears 165 mounted on the Driven Shaft 142 that have the ability to engage or disengage with the Driven Shaft 142. The sizes of these circular Duration Extender Module gears are selected so that the angular velocities of the driven gears match the final angular velocities of the transmission. The low and high constant angular velocities of the non-circular gears is selected such that the angular velocities of the Duration Extender Module Driven Gears 165 are equal to the angular velocities of the Transmission Driven Gears 160. If the ratios of angular velocities of successive Transmission Driven Gears 160 are not identical, then multiple Duration Extender Modules 1001 will be needed.
While it is convenient to place the Driven-Non-Circular-Gear along with the Duration Extender Module Driving Gear 61s on the Driving shaft 144, it can be placed on a separate shaft parallel to the Driving shaft 144. And similarly, while it is convenient to place the Driving-Non-Circular-Gears along with the larger speed reduction gear on the Driven Shaft 142 it can be placed on a separate shaft parallel to the Driving shaft 144 or Driven Shaft 142.
Using multiple stages of reductions as shown in
It is also possible to use one of the pair of gears of transmission gears as the Duration Extender Module Driving Gear 61 and Duration Extender Module driven gear. It will be beneficial to have the smallest driving gear pairing with the largest driven gear to use as the Duration Extender driving gears and Duration Extender Module Driven Gears 165. That is the smallest driving gear pairing with the largest driven gear has the dual purpose of being a transmission gear and the Duration Extender driving gears and Duration Extender Module Driven Gears 62.
This concept is shown in
In configuration shown in
The configuration shown in
Ratio A Gear and axially linking Duration Extender Module Driving-Non-Circular-Gear to Driven speed reduction gear 167) The configuration shown in
The configuration shown in
The configuration in
The configuration in
By using a multi radii/non-circular sprocket, as shown in
By using various combinations of sprockets and gear there are many ways to achieve uninterrupted shifting.
Following are a few of different scenarios using different combinations of gears and sprockets
A set of circular Transmission Driving Gears 161 varying in size are rigidly mounted on a Driving shaft 144. A set of matching circular Transmission Driven Gears 160 freewheeling on a Driven Shaft 142 with its axis placed parallel to the axis of the Driving shaft 144, with the ability to engage or disengage to any specific circular Transmission Driven Gears 160 using dog clutch or similar devices. One or more Duration Extender Module 1001 comprising a Duration Extender Module Driving Non-Circular Gear 59 axially connected to one of the Transmission Driven Gears 160, mounted on the Driven Shaft 142 or a larger driven gear of a pair of speed reduction circular gears mounted on the Driven Shaft 142 or on a Duration Extender Module Intermediate Driving shaft 144 parallel to the Driving shaft 144 driven by a smaller Driving-Non-Circular-Gear of the pair of speed reduction gears, with a Linking Mechanism 153 to engage/disengage, is mounted on the Driving shaft 144 a Duration Extender Module Driven Non-Circular Gear 60, meshing with the Duration Extender Module Driving Non-Circular gear 59, is mounted freewheeling on the Driving shaft 144 or on a Duration Extender Intermediate Driven Shaft 142 parallel to Driving shaft 144, one or more Duration Extender Module Driving Circular Gears 61 axially connected to the Duration Extender Module Driven Non-Circular Gear 60, and meshed to the corresponding Duration Extender Module Driven Circular Gears 62 mounted on the Driven Shaft 142, with the ability to engage or disengage with the Driven Shaft 142.
A set of circular Transmission Driving Gears 161 varying in size are rigidly mounted on a Driving shaft 144, a set of matching circular Transmission Driven Gears 160 freewheeling on a Driven Shaft 142 with its axis placed parallel to the axis of the Driving shaft 144, with the ability to engage or disengage to any specific circular Transmission Driven Gears 160, One or more Duration Extender Module 1001 comprising a Duration Extender Driving Circular Gear 61 mounted on the Driving shaft 144, is meshed with Duration Extender Driven Circular Gear 62 mounted on a Duration Extender Module Intermediate Driving shaft 144 and which is axially connected to a Duration Extender Module Driving Non-Circular Sprocket 147 having two or more constant radii pitch circle with teeth uniformly spaced that is linked with a Duration Extender Module Driven Non-Circular Sprocket 147 mounted on the Driven Shaft 142.
A set of circular Transmission Driving Gears 161 varying in size are rigidly mounted on a Driving shaft 144. A set of matching circular Transmission Driven Gears 160 freewheeling on a Driven Shaft 142 with its axis placed parallel to the axis of the Driving shaft 144, with the ability to engage or disengage to any specific circular Transmission Driven Gears 160. One or more Duration Extender Module 1001 comprising, a Duration Extender Module Driving Circular Gear 61 axially connected to one of the Transmission Driven Gears 160, mounted on the Driven Shaft 142 or a larger driven gear of a pair of speed reduction circular gears mounted on the Driven Shaft 142 or on a Duration Extender Intermediate Driving shaft 144 parallel to the Driving shaft 144 a smaller Driving-Non-Circular-Gear of the pair of speed reduction gears via a Linking Mechanism 153 to engage/disengage is mounted on the Driving shaft 144, a Duration Extender Module Driven Circular Gear 62 meshing with the Duration Extender Module Driving Circular Gear 61 is mounted freewheeling on the Driving shaft 144 or on a Duration Extender Intermediate Driven Shaft 142 parallel to Driving shaft 144, one or more Duration Extender Module Driving Non-Circular gear 59s axially connected to the Duration Extender Module Driven Circular Gear 62, and meshed to the corresponding Duration Extender Module Driven Non-Circular Gear 60, meshing with the Duration Extender Module Driving Non-Circular gear 59, is mounted on the Driven Shaft 142, with the ability to engage or disengage with the Driven Shaft 142.
A set of circular Transmission Driving Gears 161 varying in size are rigidly mounted on a Driving shaft 144. A set of matching circular Transmission Driven Gears 160 freewheeling on a Driven Shaft 142 with its axis placed parallel to the axis of the Driving shaft 144, with the ability to engage or disengage to any specific circular Transmission Driven Gears 160. One or more Duration Extender Module 1001 comprising, a Duration Extender Driving Circular Sprocket is axially connected to one of the Transmission Driven Gears 160, mounted on the Driven Shaft 142 or a larger driven gear of a pair of speed reduction circular gears mounted on the Driven Shaft 142 or on a Duration Extender Intermediate Driving shaft 144 parallel to the Driving shaft 144 a smaller Driving-Non-Circular-Gear of the pair of speed reduction gears via a Linking Mechanism 153 to engage/disengage, is mounted on the Driving shaft 144, a Duration Extender Module Driven Circular Sprocket is linked by a Chain/Belt 139 and via a Tensioner Sprocket 170, with the Duration Extender Module Driving Circular Sprocket is mounted freewheeling on the Driving shaft 144 or on a Duration Extender Intermediate Driven Shaft 142 parallel to Driving shaft 144. This arrangement allows the Driven Circular Sprocket to spin in the same direction of the Driving Circular Sprocket.
This can also be achieved by replacing the both the Circular Sprockets with a Driving circular gear 63 connected to the Driven Circular Gear 140 via an intermediate Circular Gear placed on an auxiliary shaft. With this arrangement the rotation of Driving and Driven Shafts 144 and 142 can be achieved.
One or more Duration Extender Module Non-Circular Driving Sprockets with teeth uniformly spacing axially connected to the Duration Extender Module Driven Circular Sprocket, and linked via a Chain/Belt 139 and a Tensioner Sprocket 170 to the corresponding Duration Extender Module Circular or Non-Circular Driven Sprockets with teeth uniformly spaced as the Duration Extender Module Non-Circular Driving Sprockets mounted on the Driven Shaft 142, with the ability to engage or disengage with the Driven Shaft 142.
A set of circular Transmission Driving Gears 161 varying in size are rigidly mounted on a Driving shaft 144. A set of matching circular Transmission Driven Gears 160 freewheeling on a Driven Shaft 142 with its axis placed parallel to the axis of the Driving shaft 144, with the ability to engage or disengage to any specific circular Transmission Driven Gears 160. One or more Duration Extender Module 1001 comprising a Duration Extender Driving Circular Sprocket is axially connected to one of the Transmission Driven Gears 160, mounted on the Driven Shaft 142 or a larger driven gear of a pair of speed reduction circular gears mounted on the Driven Shaft 142 or on a Duration Extender Intermediate Driving shaft 144 parallel to the Driving shaft 144 a smaller Driving-Non-Circular-Gear of the pair of speed reduction gears via a Linking Mechanism 153 to engage/disengage, is mounted on the Driving shaft 144, a Duration Extender Module Driven Circular Sprocket is linked by a Chain/Belt 139 and via a Tensioner Sprocket 170, with the Duration Extender Module Driving Circular Sprocket is mounted freewheeling on the Driving shaft 144 or on a Duration Extender Intermediate Driven Shaft 142 parallel to Driving shaft 144. One or more Duration Extender Module Non-Circular Driving Sprockets with teeth uniformly spacing axially connected to the Duration Extender Module Driven Circular Sprocket, and linked via a Chain/Belt 139 and a Tensioner Sprocket 170 to the corresponding Duration Extender Module Circular or Non-Circular Driven Sprockets with teeth uniformly spaced as the Duration Extender Module Non-Circular Driving Sprockets mounted on the Driven Shaft 142, with the ability to engage or disengage with the Driven Shaft 142.
A set of circular Transmission Driving Sprockets 162 varying in size are rigidly mounted on a Driving shaft 144. A set of matching circular Transmission Driven Sprockets 164 freewheeling on, a Driven Shaft 142 with its axis placed parallel to the axis of the Driving shaft 144, with the ability to engage or disengage to any specific circular transmission driven sprocket 164. One or more Duration Extender Module 1001 comprising, a Duration Extender Module Driving Circular Sprocket is axially connected to one of the Transmission Driven Sprockets 164, mounted on the Driven Shaft 142 or a larger driven sprocket of a pair of speed reduction circular sprockets mounted on the Driven Shaft 142 or on a Duration Extender Intermediate Driving shaft 144 parallel to the Driving shaft 144. A smaller driving circular sprocket of the pair of speed reduction sprockets rigidly mounted on the Driving shaft 144. A Duration Extender Module Driven Circular Sprocket is linked by a Chain/Belt 139 and via a Tensioner Sprocket 170, with the Duration Extender Module Driving Circular Sprocket is mounted freewheeling on the Driving shaft 144 or on a Duration Extender Intermediate Driven Shaft 142 parallel to Driving shaft 144. One or more Duration Extender Module Non-Circular Driving Sprockets with teeth uniformly spacing axially connected to the Duration Extender Module Driven Circular Sprocket, and linked via a Chain/Belt 139 and a Tensioner Sprocket 170 to the corresponding Duration Extender Module Circular or Non-Circular Driven Sprockets with teeth uniformly spaced as the Duration Extender Module Non-Circular Driving Sprockets mounted on the Driven Shaft 142, with the ability to engage or disengage with the Driven Shaft 142.
A set of circular Transmission Driving Sprockets 162 varying in size are rigidly mounted on a Driving shaft 144. A set of matching circular Transmission Driven Sprockets 164 freewheeling on, a Driven Shaft 142 with its axis placed parallel to the axis of the Driving shaft 144, with the ability to engage or disengage to any specific circular transmission driven sprockets 164. One or more Duration Extender Module 1001 comprising a Duration Extender Module Driving Non-Circular Sprocket 147 having two or more constant radii pitch circle with teeth uniformly spaced is axially connected to one of the Transmission Driven Sprockets 164, mounted on the Driven Shaft 142 or a larger driven sprocket of a pair of speed reduction circular sprockets mounted on the Driven Shaft 142 or on a Duration Extender Intermediate Driving shaft 144 parallel to the Driving shaft 144. A smaller Driving-Non-Circular-Gear of the pair of speed reduction sprockets via a Linking Mechanism 153 to engage/disengage, is mounted on the Driving shaft 144. A Duration Extender Module Driven Circular or Non-Circular Sprocket with teeth uniformly and identical spacing as the Duration Extender Module Driving Non-Circular Sprocket 147 is linked by a Chain/Belt 139 and via a Tensioner Sprocket 170, with the Duration Extender Module Driving Non-Circular Sprocket 147, is mounted freewheeling on the Driving shaft 144 or on a Duration Extender Intermediate Driven Shaft 142 parallel to Driving shaft 144. One or more Duration Extender Module Driving Circular Sprocket axially connected to the Duration Extender Module Driven Non-Circular Sprocket 147 and linked via a Chain/Belt 139 to the corresponding Duration Extender Module Driven Circular Sprocket mounted on the Driven Shaft 142, with the ability to engage or disengage with the Driven Shaft 142.
A set of circular Transmission Driving Sprockets 162 varying in size are rigidly mounted on a Driving shaft 144. A set of matching circular Transmission Driven Sprockets 164 freewheeling on a Driven Shaft 142 with its axis placed parallel to the axis of the Driving shaft 144, with the ability to engage or disengage to any specific circular transmission driven sprockets 164. One or more Duration Extender Module 1001 comprising a Duration Extender Module Driving Non-Circular gear 59 axially connected to one of the Transmission Driven Sprockets 164, mounted on the Driven Shaft 142 or a larger driven gear of a pair of speed reduction circular gears mounted on the Driven Shaft 142 or on a Duration Extender Intermediate Driving shaft 144 parallel to the Driving shaft 144 driven by a smaller Driving-Non-Circular-Gear of the pair of speed reduction gears via a Linking Mechanism 153 to engage/disengage, is mounted on the Driving shaft 144. A Duration Extender Module Driven Non-Circular Gear 60, meshing with the Duration Extender Module Driving Non-Circular gear 59, is mounted freewheeling on the Driving shaft 144 or on a Duration Extender Intermediate Driven Shaft 142 parallel to Driving shaft 144. One or more Duration Extender Module Driving Circular Gears 61 axially connected to the Duration Extender Module Driven Non-Circular Gear 60 and meshed to the corresponding Duration Extender Module Driven Circular Gears 62 mounted on the Driven Shaft 142, with the ability to engage or disengage with the Driven Shaft 142.
A set of circular Transmission Driving Sprockets 162 varying in size are rigidly mounted on a Driving shaft 144. A set of matching circular Transmission Driven Sprockets 164 freewheeling on a Driven Shaft 142 with its axis placed parallel to the axis of the Driving shaft 144, with the ability to engage or disengage to any specific circular transmission driven sprockets 164. One or more Duration Extender Module 1001 comprising a Duration Extender Module Driving Circular Gear 61 axially connected to one of the Transmission Driven Sprockets 164, mounted on the Driven Shaft 142 or a larger driven sprocket of a pair of speed reduction circular sprockets mounted on the Driven Shaft 142 or on a Duration Extender Intermediate Driving shaft 144 parallel to the Driving shaft 144. A smaller driving circular sprocket of the pair of speed reduction sprockets rigidly mounted on the Driving shaft 144, A Duration Extender Module Driven Circular Gear 62 meshing with the Duration Extender Module Driving Circular Gear 61 is mounted freewheeling on the Driving shaft 144 or on a Duration Extender Intermediate Driven Shaft 142 parallel to Driving shaft 144. One or more Duration Extender Module Driving Non-Circular gear 59s axially connected to the Duration Extender Module Driven Circular Gear 62 and meshed to the corresponding Duration Extender Module Driven Non-Circular Gear 60, meshing with the Duration Extender Module Driving Non-Circular gear 59, is mounted on the Driven Shaft 142, with the ability to engage or disengage with the Driven Shaft 142.
A set of circular Transmission Driving Sprockets 162 varying in size are rigidly mounted on a Driving shaft 144. A set of matching circular Transmission Driven Sprockets 164 freewheeling on a Driven Shaft 142 with its axis placed parallel to the axis of the Driving shaft 144, with the ability to engage or disengage to any specific circular transmission driven sprockets 164. One or more Duration Extender Module 1001 comprising a Duration Extender Driving Circular Sprocket is axially mounted on the Driving shaft 144 linked by a Chain/Belt 139 to a Duration Extender Module Driven Sprocket 146 mounted on a Duration Extender Module Intermediate Driving shaft 144. A Duration Extender Module Driving Non-Circular Sprocket 147 with teeth uniformly and identical spacing is axially connected to the Duration Extender Module Driven Sprocket 146, via a Chain/Belt 139 and a Tension Sprocket, linked to a Duration Extender Module Driven Non-Circular Sprocket 147 mounted on the Transmission Driven Shaft 142.
A set of circular Transmission Driving Gears 161 varying in size are rigidly mounted on a Driving shaft 144. A set of matching circular Transmission Driven Gears 160 freewheeling on a Driven Shaft 142 with its axis placed parallel to the axis of the Driving shaft 144, with the ability to engage or disengage to any specific circular Transmission Driven Gears 160. One or more Duration Extender Module 1001 comprising a Duration Extender Module Driving Circular Sprocket is axially mounted on the Driving shaft 144 linked by a Chain/Belt 139 to a Duration Extender Module Driven Sprocket 146 mounted on a Duration Extender Module Intermediate Driving shaft 144. A Duration Extender Module Driving Non-Circular gear 59 is axially connected to the Duration Extender Module Driven Sprocket 146 and paired with a Duration Extender Module Driven Non-Circular Gear 60 mounted on the Transmission Driven Shaft 142.
A set of circular Transmission Driving Sprockets 162 varying in size are rigidly mounted on a Driving shaft 144 and a set of matching circular Transmission Driven Sprockets 164 freewheeling on a Driven Shaft 142 with its axis placed parallel to the axis of the Driving shaft 144, with the ability to engage or disengage to any specific circular transmission driven sprockets 164. One or more Duration Extender Module 1001 comprising a Duration Extender Driving Circular Gear 61 mounted on the Driving shaft 144 and meshed to a Duration Extender Module Driven Gear mounted on a Duration Extender Module Intermediate Driving shaft 144. A Duration Extender Module Driving Non-Circular gear 59 is axially connected to the Duration Extender Module Driven Gear, is meshed to a Duration Extender Module Driven Non-Circular Gear 60 mounted on the Transmission Driven Shaft 142.
The same shifting concept can be applied to all the above scenarios to achieve uninterrupted gear shifting, only difference is that gears are replaced with sprockets that is ideal for the scenarios.
Additionally, by using a planetary gear system this Pseudo “Continuously” Variable Transmission can be converted to a Pseudo “Infinitely” Variable Transmission, by
a) feeding driving sprocket to either sun or ring or carrier of the planetary system,
b) feeding driven sprocket to either of the remaining two elements and
c) connecting the third element to the wheel.
By appropriately sizing the planetary gear system, forward, reverse, and neutral can be achieved.
to next.
All circular and non-circular gears in
II) Utilizing Non-Circular Gears with “Bald” Regions (without Teeth) and/or Geneve Wheel Mechanism with Custom Slot Path for Multi-Speed Uninterrupted Shifting (MSTUS)
The synchronous shifting is achieved by engaging the driving and the driven gears by aligning them in a single operating plane 1003 and disengaging them by offsetting one of them out of the operating plane 1003. There are three configurations to achieve this.
1) In the first configuration each of the gear pairs is co-planer and they are all made active or inactive by engaging or disengaging with their shafts with a dog clutch 53 individually.
2) In the second configuration the active gear pairs are moved to one common operating plane 1003.
3) In the third configuration there are multiple operating planes 1003 with the active and inactive gear pairs have their own operating plane 1003. The gear pairs are active when they are co-planer with each other, and they are inactive when placed at an offset with each other. Below is a detailed description of each of these configurations.
1) Transmission Using Dog Clutch:
Here a set of driving transmission gears along with driving non-circular gears 143 are mounted on a drive shaft. A set of driven conjugate transmission gears along with driving non-circular gears 143 are mounted on a Driven Shaft 142. One of the gears in each pair has a dog clutch 53 to engage or disengage with its shaft. For every pair of adjacent value of gears has a non-circular pair with its pitch curve having a region of both the circular gear's pitch curves. These pitch curves are sandwiched with an up-shift ramp and a downshift ramp. These ratios are cycled once for every rotation. The uninterrupted shifting is achieved when the non-circular gears, in its cycle matches with the pitch curve of the currently engaged circular transmission pairs, the non-circular gear is also simultaneously engaged with its shaft via its dog clutch 53. Then immediately the currently engaged circular pair is disengaged. After the non-circular gear passes through the ramp and reaches the targeted ratio, the targeted circular gear is simultaneously engaged. Before the non-circular gear reaches the next ramping zone, it is disengaged with its shaft. Thus, the shifting from the existing ratio to the targeted ratio is achieved uninterrupted.
2) Single Operating Plane: (
With the driving and driven sets of several pairs of gears, the two smallest size full gears 13 and 16 are placed co-planer at a fixed center to center distance. Spring loaded Gear Segment 151s forming full larger size gears are placed co-axial but offset to the full-size gears. The larger gears 15 and 18 have an orifice matching the gear profile of the smallest gear. These spring 10 loaded segments of larger gears 15 and 18 can be moved in and out of operating plane 1003 to achieve several input-to-output ratios.
A pair of driving and driven gear/Gear Segment 151s are selected so that the center-to-center distance which is the sum of the radii of the driving and driven pairs is constant. If the driving or driven gear is to be changed from smaller to larger size, then the larger Gear Segment 151s are slipped into the operating plane 1003 for one gear, and the larger Gear Segment 151s are slipped out of the operating plane 1003 for the other gear so that two gears can mesh with each other. The offset planes of segments of gears of driving and driven sets are so placed so that the largest gears of both sets do not interfere with each other. This can be achieved by placing the segment of large gears are placed on either side of the gears are slipped in and out in the regions where driving and driven gears are not in contact. Since the gear teeth are not loaded there is negligible friction to overcome to slide them into the operating plane 1003. In order for the teeth of the driving and driven gears to mesh exactly, the gears may have to be rotated to a certain correct position. This can be achieved using position sensors with computer-controlled solenoids. While switching from one ratio to another the gears will experience sudden change in rotational speed, and this will deteriorate the life of the gears. To eliminate this the driving or the Driven Shaft 142 is fitted with a rotational shock absorber such as a torsion spring 51. Another way to solve this is to use an intermediate non-circular gear to ramp up or ramp down from the active ratio to the targeted ratio. The non-circular gear will have four zones.
Since this non-circular gear or otherwise known as crescent transition gears 14 and 17 with its rotational origin having an orifice of the smallest gear and also matching the portion of the contour, the shape is like a “crescent” as shown in
An alternative way to having a small gear profile is to place the driving and driven transition gear segments 7 and 8 on non-circular telescopic tubular shafts 46, 47, 48 and 49 as shown in
Here the ideal orientation for the up-shift zone and the downshift zone occurs in cycles. This happens when the driving gear and the driven gear finish a complete revolution at the same time. Because in low speed or high speed the driving gear shaft and the driven gear shaft rotate at a different rate. However, the requirement for the non-circular gear to work they must rotate at a constant speed (1:1). So, the ideal time to use the non-circular gear is cyclic.
Here the up shift is achieved by
Similarly, the downshift is achieved by
3) Multiple Operating Planes
Here, there are two ways of operating this. Gears pairs are placed offset and made co-planer only when desired to make them active. Every gear pair has its own operating plane 1003. The gear pairs are engaged or disengaged by making them co-planer or offset. Here driving or driven or both sets of gears are segmented. All the segments of each gear form a full gear. Each segment is capable of axially moving individually. In order to engage or disengage, each segment is individually moved in or out of the operating plane 1003 one at a time. This is done when none of the teeth in that segment is in contact with its conjugate. This way even helical gear can be brought in alignment to mesh with each other. Since the gear teeth are not loaded there is negligible friction to overcome to slide them into the operating plane.
Here also for every two pairs of driving and driven circular gears 23, 24, 25, 26 with adjacent gear ratio values, there is a non-circular gear pair 21 and 22 with four gear ratio zones. They are
Here the gear segments each are attached to a non-circular tubular telescopic shaft 46, 47, 48 and 49. These tubular shafts 46, 47, 48 and 49 are co-axial with each other. These tubes allow axial movement of the individual segment while restricting relative rotation. These tubular telescopic shafts 46, 47, 48 and 49 are notched at the joining location where it makes a partial contact with the gear segments. This is to eliminate interference during the segments are translated individually axially. The length of the notch is slightly more that the thickness of the gear segments to clear each other. The inner most tubular shaft 46 has its orifice matching the non-circular shaft 19 or 20 it is mounted on. Such that it is rotationally locked while axially movement is possible. This construction is same for the circular and the non-circular gears which are segmented. The tubular shafts 46, 47, 48 and 49 have a flange at the attachment plane where it is bolted to the individual gear segment, as shown if
Here up-shift is achieved by following steps: (shown in
Similarly, the downshift is achieved by the following steps: (shown in
By placing a one way bearing in the largest driven gear engaging and disengaging the low-speed gears can be eliminated from all the above steps. This scenario is shown in
Another option for multiple plane scenario is that the circular gear pairs stay meshed in the operating plane 1003 with a dog clutch 53 placed either on the driving gear or on the driven gear and engage with its shaft only during activating the gear pair. Only the non-circular gears are moved into or out of the operating plane 1003.
In this case the up shift is achieved by following steps:
The downshift is achieved by following steps:
Again, here by placing a one way bearing in the largest driven gear engaging and disengaging the low-speed gears can be eliminated from all the above steps. And to overcome the engine braking issue a dog clutch 53 can be used and activated at the low-speed largest driven gear when engine braking is desired, via a computer controller.
When segmentation is not desired the non-circular pair can have locally a void zone where the teeth are removed below the dedendum of the tooth. The non-circular gear does not make contact with the conjugate non-circular gear at this void zone. The non-circular gear is axially moved into or out of the operating plane 1003 when the non-circular pair is in the void zone. The non-circular gear can be in addition to the four zones or replacing one of the zones. When the void zone is replacing one of the zones, two or more non-circular gears will be conjugates to a full non-circular gear. If the void zone replaces up-shift zone this can be paired with the full non-circular gear during downshift and if the void zone replaces the downshift zone this can be paired with the full non-circular gear during up-shift. If the void zone is replacing low speed zone, a One-way bearing 5050 installed at the largest driven gear will fulfill the need for this missing zone. Again, here by adding a dog clutch 53 to engage the largest driven gear to its shaft for engine braking.
Electric motors spin at a very high speed when compared with ICEs. In all the scenarios mentioned earlier, the shifting occurs in nano seconds. It may be beneficial if this duration can be extended so it allows more time for the shifting to occur. The following arrangements with a “duration extender module” extend the duration for the shifting. Here uninterrupted shifting of two-speed transmission is explained. The same idea can be extended to more than two-speed transmission.
The general arrangement is
1) a set of circular Transmission Driving circular gears 63 varying in size are rigidly mounted on a Driving shaft 144. A set of matching circular Transmission Driven circular gears placed on bearings so they freewheel on the Driven Shaft 142. The largest driven circular gear 140 is placed on a One-way bearing 50 on the Driven Shaft 142. The Driven Shaft 142 is placed parallel to the axis of the Driving shaft 144, at a distance (CTR) equal to the sums of the radii of the conjugate pair. These driven gears have the ability to engage or disengage with the Driven Shaft 142 via a dog clutch 53. Here there is no need for a synchronizer since the engagement and dis-engagement occurs when the shaft and the driven gears rotate at a same angular velocity. So just a dog clutch 53 will be sufficient. There is one dog clutch 53 for each one of the driven gears so that they can be engaged or disengaged independently in any order with respect to each other. For every two pairs of transmission driving and driven circular gears with adjacent gear ratio value, there is a Duration Extender Module.
The duration extender module comprises
Here the low-speed zone has the lower of the two gear ratios of the two circular gear pairs. The high-speed zone has the higher of the two gear ratios of the two circular gear pairs. They are separated by ramping up from lower ratio to the higher ratio. This is used during an up-shift operation. The ramping down from the higher ratio to the lower ratio. This is used during a downshift operation.
The driven non-circular gear 141 is meshed with the Driving Non-Circular gear 143 and is placed on the driving shaft with a bearing, so it freewheels. A Duration Extender Module Driving Circular Gear 61 axially connected to the Duration Extender Module Driven Non-Circular Gear 60. This meshes to a corresponding Duration Extender Module Driven Circular Gear 62 that is mounted on the Driven Shaft 142. It is rotationally locked with the ability to axially translate to be co-planer to engage or to be offset to disengage with the freewheeling Duration Extender Module Driving Circular Gear 61.
with this arrangement the angular velocity of the Duration Extender Module Driving Circular Gear 61 constantly alters between the angular velocity of the two circular transmission driving gear ramping up and down. Here the Duration Extender Module Driving and driven Circular Gears 61 and 62 have identical pitch curve as the higher speed transmission driving and driven circular gears respectively.
The same arrangements can be used with three dog clutch 53 which connect the Duration Extender Module Driven Circular Gear 62 and both the transmission gears to the Driven Shaft 142 individually. Since moving of the Duration Extender Module Driven Circular Gear 62 axially require segmentation, the other option is to use dog clutch 53 individually.
Here the sequence for an uninterrupted shift from existing gear ratio to a targeted gear ratio, is achieved by,
A) With the Driven Shaft 142 engaged to one of the existing Transmission Driven gears.
B) when the angular velocity of the Duration Extender Module Driving Circular Gear 61 is same as the angular velocity of the currently engaged Transmission Driving Gear and synchronized the Duration Extender Module Driven Circular Gear 62 meshes with Duration Extender Module Driven Circular Gear 62 and
C) immediately the currently engaged Transmission Driven Gear is disengaged from the Driven Shaft 142 while the currently engaged Duration Extender Module Driven Circular Gear 62 is still in the same region and
D) after the Duration Extender Module Driven Circular Gear 62 passes through the ramp region and reaches and is well within region of the targeted Transmission Driven Gear's angular velocity and synchronized, the Transmission Driven Gear with the targeted ratio is also engaged to the Driven Shaft 142 and
E) immediately the Duration Extender Module Driven Circular Gear 62 is disengaged from the Driven Shaft 142 while in the same region achieving uninterrupted shifting.
Double DEM Transmission with Non-Circular Gears
A set of driving circular gears 63 are rigidly mounted on a drive shaft 64. Correspondingly, there is a set of freewheeling conjugate driven gears 65. A double DEM driving circular gear 66 is axially attached to one of them. The freewheeling conjugate driven gears 65 and the double DEM driving circular gear 66 each use a dog clutch 5353 to engage or disengage with the intermediate shaft 67 they are mounted on. The largest gear is placed on a One-way bearing 5050. A segmented freewheeling double DEM driven gear 68, that is capable of moving axially out of or into an operating plane 1003 with the double DEM driving circular gear 66, is axially attached to a freewheeling DEM driving non-circular gear 69. The segmented freewheeling double DEM driven gear 68 and the double DEM driving circular gear 66 are both placed on an output-shaft 70. The freewheeling DEM driving non-circular gear 69 meshes with a freewheeling DEM driven non-circular gear 71 which is axially linked with a freewheeling DEM driving circular ring gear 72. Both the freewheeling DEM driving circular ring gear 72 and the freewheeling DEM driven non-circular gear 71 are both mounted on the drive shaft 64. The DEM driving circular ring gear 72 meshes with a DEM intermediate circular planet gear 73 rigidly mounted on the intermediate shaft 67 where a driving final output gear 75 that is rigidly mounted on the intermediate shaft, drives a driven final output gear 76.
Single DEM Transmission with Geneva Wheels
A set of driving circular gears 63 are rigidly mounted on a drive shaft 64. There is a set of freewheeling conjugate driven gears 65 each having a dog clutch 53 to engage or disengage with an output shaft 70 they are mounted on. The largest gear is placed on a One-way bearing 50 and is axially attached to a DEM driving Geneva pin wheel with retractable pins 79. The retractable pins are operated via rotationally fixed axially movable spiral ramp/cam 168 or solenoids activated by position sensor sensing angle of the drive shaft 64 and driven shaft. The pins are extended only during when the pins are in contact with the slot in the region where the pin and wheel are in contact. When the pins are not in contact with the slot, the pins are retracted in that region. Also, the slot can ramp up when the pin and slot engagement region at the near end such that the pins are pushed out to the retracted position. The DEM driving Geneva pin wheel 79 engages with DEM driven Geneva slot wheel 81, mounted on a Geneva shaft 80 along with a DEM uninterrupted shifting wheel 82 that drives a driven final output gear 75 which is mounted on the output shaft 70.
The Geneva pin wheel has non-circular pins that are capable of extending into and retracting from the Geneva slot wheel and driving it. The Geneva slot wheel having at least one slot when engaged with the pin causing the wheel to ramp up from R1 to R2 and at least one slot causing the wheel to ramp down from R2 to R1, where R1 and R2 are the ratio of the driving circular gears to the conjugate driven gears.
The sequence for an uninterrupted shift from existing gear ratio to a targeted gear ratio, is achieved by,
A) With the intermediate Shaft engaged to one of the conjugate driven gears,
B) when the angular velocity of the driven final output gear is same as the angular velocity of the currently engaged conjugate driven gear and synchronized to match the position of the pin and the slot the driven final output gear engages with the intermediate shaft via a dog clutch and
C) immediately the currently engaged conjugate driven gear is disengaged from the intermediate shaft while the currently engaged driven final output gear is still in the same region and
D) after the driven final output gear passes through the ramp region and reaches and is well within region of the targeted conjugate driven gear's angular velocity and synchronized, the conjugate driven gear with the targeted ratio is also engaged to the intermediate Shaft via a dog clutch and
E) immediately the driven final output gear is disengaged from the intermediate shaft while in the same region achieving uninterrupted shifting.
Double DEM Transmission with Geneva Wheels
A set of driving circular gears 63 are rigidly mounted on a drive shaft 64. Correspondingly, there is a set of freewheeling conjugate driven gears 65. A double DEM driving circular gear 66 is axially attached to one of them. The freewheeling conjugate driven gears 65 and the double DEM driving circular gear 66 each use a dog clutch 53 to engage or disengage with the intermediate shaft 67 they are mounted on. The largest gear is placed on a One-way bearing 50. A double DEM driven gear 83 meshing with the double DEM driving circular gear 66, is axially attached to a DEM driving Geneva pin wheel with retractable pins 79. The double DEM driven gear 83 and the double DEM driving circular gear 66 are both placed on a Geneva shaft 80. The DEM driving Geneva pin wheel 79 engages with a DEM driven Geneva slot wheel 81 which is axially linked with a DEM uninterrupted shifting wheel 82 via a train of gears 52. Both the DEM uninterrupted shifting wheel 82 and the DEM driven Geneva slot wheel 81 are both mounted on the intermediate shaft 64. A driving final output gear 75 that is rigidly mounted on the intermediate shaft 67, drives a driven final output gear 76 rigidly mounted on an output shaft 70.
Here the Geneva pin wheel has non-circular pins that are capable of extending into and retracting from the Geneva slot wheel driving it. When the pins are retracted the Geneva pin wheel does not engage with the Geneva slot wheel. The pins are extended only during when the pins are in contact with the slot in the region where the pin and wheel are in contact. When the pins are not in contact with the slot, the pins are retracted in that region. Also, the slot can ramp up when the pin and slot engagement region at the near end such that the pins are pushed out to the retracted position. The pins are extended only when the shifting is desired. The Geneva slot wheel has at least one slot causing the wheel to ramp from an angular velocity ratio of 1:1 between the Geneva pin wheel and the Geneva slot wheel to a ratio 1:(R1/R2), and at least one slot causing the wheel to ramp from (R1/R2):1 to a ratio 1:1, where, R1 and R2 are the angular velocity ratio of the driving circular gears 63 to the conjugate driven circular gears 62.
The sequence for an uninterrupted shift from existing gear ratio to a targeted gear ratio, is achieved by,
A) With the intermediate Shaft engaged to one of the conjugate driven gears,
B) when the angular velocity of the driving final output gear is same as the angular velocity of the currently engaged conjugate driven gear and synchronized to match the position of the pin and the slot the driving final output gear engages with the intermediate shaft via a dog clutch and
C) immediately the currently engaged conjugate driven gear is disengaged from the intermediate shaft while the currently engaged driving final output gear is still in the same region and
D) after the driving final output gear passes through the ramp region and reaches and is well within region of the targeted conjugate driven gear's angular velocity and synchronized, the conjugate driven gear with the targeted ratio is also engaged to the intermediate Shaft via a dog clutch and
E) immediately the driving final output gear is disengaged from the intermediate shaft while in the same region achieving uninterrupted shifting.
Geneva Wheel Mechanism with NO DEM with Geneva Pin and Slot Wheel
A set of driving gears and one or more Geneva pin wheels with retractable pins are rigidly mounted on a drive shaft and a set of conjugate driven gears along with one or more Geneva slot wheels is mounted on the Driven Shaft 142. Either the driving gears, or the driven gears, or both driving and driven gears have the capability to selectively engage with their respective shaft via a clutch/dog clutch or any other means. The Geneva pin wheels or slot wheels or both pin and slot wheels are either rigidly attached via a dog clutch or clutch or any other means or have the capability to engage or disengage with their respective shaft. If there are only two angular velocity ratios for the transmission, the most inexpensive option with the least number of components is to make the largest driving gear with the ability to selectively engage to its shaft and the largest driven gear with a one way bearing, and the Geneva pin and slot wheels rigidly connected to their respective shafts. The path of the Geneva slots is shaped such that the pin wheels rotate the slot wheels at constant angular velocity ratios of the gear pairs sandwiching a ramp up or a ramp down region to reach the targeted ratio. These are functional regions since they are used to transition the angular velocity ratio from one value to the immediate next value required. The Geneva pin and wheel mechanism has two or more regions of constant angular velocity ratio and two or more regions of ramp. Having a separate Geneva pin wheel and slot wheel for each ramp, whether up or down, will be the most practical and easiest way to implement this. The Geneva pins are retractable and can be circular or non-circular in cross-section. If the Geneva pins are non-retractable, an alternative way to achieve the above is by using dog clutch or synchronized clutch or similar devices. Ramps on the slots can be used to push the Geneva pin to retracted position as shown in 98B and spring-loaded gates on the slot be used to prevent the Geneva pin entering into another slot when the slot paths cross each other as shown in 67A, B and C. 67A shows a “door” type gate and 67B&C show lift gate type which are activated by the Geneva pin. The spring brings the gate to original position after the pin passes thru.
The transition from lower to higher angular velocity ratio by ramping up is shown in
The sequence for achieving an uninterrupted shift from existing gear ratio to a targeted gear ratio is as follows:
A) With the existing driven gear engaged to its shaft and the conjugate driving gear,
B) When the Geneva pin and slot wheels are oriented to synchronize with the existing gear ratio, the Geneva pins are extended to engage with the slot that ramps to the targeted ratio ramping from existing ratio to the targeted ratio
C) Immediately either the currently engaged conjugate driven gear or the driving gear is disengaged from its shaft and the angular velocity ratio of the Geneva pin and slot wheels ramps to the targeted ratio.
D) when the Geneva pin and slot wheel mechanism is well within region of the targeted ratio and synchronized with the targeted ratio, the driving gear and the conjugate driven gear with the targeted ratio are also engaged to their respective shafts via a dog clutch or clutch or any other means and
E) Immediately the Geneva slot and pin wheels are disengaged by retrieving the pins (84) achieving uninterrupted shifting.
For “N” number of gear pairs 87 we can use “N−1” Geneva pin and slot wheels where each pair is used to ramp us as well as ramp down. We will need twice the number of Geneva pin and slot wheels if each is used to either ramp up or ramp down and not both. NO DEM Geneva pin/slot wheel assembly 88 is shown in
Alternatively, all the driving and driven gears and the Geneva pin and slot wheels all have an ability to engage or disengage with their respective shaft via a dog clutch or synchronous clutch and all the driven gears and the Geneva slot wheels are rigidly mounted onto the Driven Shaft 142s or all the driven gears and the Geneva slot wheels are have an ability to engage or disengage with the driving shaft via a dog clutch or synchronous clutch and all the driven gears and the Geneva slot wheels are rigidly mounted onto the driven shafts 142 (vice versa). The largest driven gear is placed on a one-way bearing so that disengaging that gear to its shaft is unnecessary. The retractable pins are activated via rotationally fixed axially movable spiral ramp/cam 168 or solenoid valves controlled by a controller that uses position sensor placed on the gears to determine the timing of extending or retracting the pins. In addition to the functional region there is a non-functional region where the Geneva pin wheel has additionally one or more pins on the Geneva pin wheel and additional one or more slots on the Geneva slot wheel to rotate Geneva slot wheel rapidly and simultaneously disengaging the Geneva pin and slot wheels to complete a full rotation such that the rotation ratio of the Geneva pin wheel to the rotation of the Geneva slot wheel is an integer or a reciprocal of an integer. These slots can be radial since this a nonfunctional region and the rate at which this is achieved is not important.
In all the scenarios, instead of using retracting pins an alternate way to disengage the Geneva wheels can be achieved by disengaging the Geneva pin and slot wheels with a clutch or dog clutch.
All gears are either installed rigidly or via a one way bearing or with a clutch with synchro or dog clutch, to its shaft. The one-way bearing includes the one way bearing that is capable of all the selectable operating modes such as freewheeling clockwise, freewheeling counterclockwise, freewheeling both clockwise and counterclockwise and totally locking. This technology is currently known as multi-mode clutch module (MMCM) that uses a cam to select the operating mode. This makes the one-way bearing switch mode when the engine or the electric motor switches direction.
The Geneva pin wheel has spiral flutes on the ID. A matching spiral fluted collar 89 is sandwiched between the Geneva pin wheel and the driving shaft. An axial movement of the spiral fluted collar with respect to the Geneva pin wheel will cause a rotation of the Geneva pin wheel with respect to the driving shaft. The ability to rotate Geneva slot wheel with respect to its shaft will allow precise engagement of the pins to the Geneva slot wheel 61. This also can be achieved with a stepper motor with position sensors. There are also several other ways to achieve this. The Geneva pinwheel and the slot wheel can also be rotated with respect to their shafts with a stepper motor 90 while they are disengaged with their respected shafts via dog clutch/synchronizer clutch. After they are oriented to a precise engaging location for the transition, they can be engaged back to their shafts via the dog clutch/synchronizer clutch as shown in
To allow repetition of the up-shift or down shift scenario it is desirable to have the driving and driven pin and slot wheel to complete an integer rotation. In other words, the rotation ratio of the driving and driven pin and slot wheel is an integer or a reciprocal of an integer. To bring the driving and the driven pin and slot wheel to an integer or a reciprocal of an integer rotation a partial circular gear 85 and 86 (driving and driven) or an additional a radial or straight Geneva slot/slots and pin/pins can be used to bring the driven slot wheel to an integer or a reciprocal of an integer rotation (as shown in
In all scenarios smallest driving gear and/or largest driven gear [any driving and/or driven] are optionally placed on a one-way bearing.
In all scenarios, all gears have the option of having a one way bearing to the shaft.
Geneva pin wheel and Geneva slot wheel with a slot with a specific geometry/path can be used in place of non-circular gears or circular gears.
To briefly describe this invention is an Infinitely Variable Transmission (IVT). Unlike existing CVT designs, this particular design does NOT depend on friction to transmit power. Most of the CVTs that exist today depend on friction to transmit power and therefore cannot be used where there is a need to transmit high power at low speed. Due to this advantage, it is possible to use this invention where high torque transmission is required. Co-axial input and output can be achieved with this layout.
The working of this CVT can be described by the following simple sequential of operations.
a) A crank pin 101 (
b) This offset Crank pin 101 is caged in
The input shaft 100 is slotted to allow the crankpin and link 109 to pass through it, allowing the longitudinal axis of the input shaft 100 or the input disk to be co-axial with the longitudinal axis of the crank pin 101. The Slotted rack holder 103 is restricted such that it can move only in the direction that is normal to its slot. A Rack 104 is fastened to the Slotted Rack holder 103, such that the Rack 104 is parallel to the Slotted rack holder's 44 direction of movement. In the alternative construction, the Crank pin shaft 115 is orthogonal to the Input shaft 100. The revolution of the crank pin 1019 about the longitudinal axis 1021 of Input disk 102 is translated to pure linear back and forth movement or reciprocating movement of the Rack 104. This mechanism is commonly known as “Scotch-Yoke-Mechanism” in the industry. The distance of this linear back and forth movement (stroke) is directly proportional to the radial distance of the Crank pin 9 from the longitudinal axis 1021 of the Input disk 102. Since the work done is constant, which is a product of force applied multiplied by the distance traveled (F*stroke), for a smaller stroke, the force applied is greater and for a longer stroke, the force applied is smaller.
c) The Rack 104 is linked to a Pinion 106 (
d) This rocking oscillation is converted to a unidirectional rotation, using a One-way bearing/Computer-Controlled-Clutch/Ratchet-mechanism 22.
One main purpose of this invention is to achieve a CONSTANT AND UNIFORM output angular velocity when the input angular velocity is constant and uniform. However, using the steps described above, this is NOT achieved, as the output is sinusoidal.
By modifying the rate of change of angular displacement of the Input disk 102, a uniform steady output can be achieved. U.S. Pat. No. 9,970,520 uses a pair of non-circular gears to achieve this. This invention achieves it by using modified Geneva mechanism customized for this.
By using a set of Geneva pin wheel 96 (
The components are grouped into modules/mechanisms for easier understanding:
Detailed description of Assembly, Sub-assembly of components/Modules and their functions:
a) Angular-Velocity-Modifier-Module (
The Driving Geneva pin wheel 96 is mounted on the Input shaft 100. The shape of the Geneva slot wheel 97 is designed to achieve the end result which is the reciprocal of sinusoidal output. Multiple pins and multiple slots are used and with an overlap of more than one pin achieving a portion of the same results simultaneously. More than one set of driving Geneva pin wheel 96 and driven Geneva slot wheel 97 can be used in a single module. The slot or the walls of the slot are terminated where a pin's path forms loop. Also, multiple modules can share a common Geneva pin wheel 96 or a common Geneva slot wheel 97. In the slot wheel 97 the paths of the slots are cut from a slot wheel 97 or the walls of the path can be raised from a slot wheel 97 or a combination of both. This is to clear the interference of the pin where the pin and slot or slot walls do not produce desired result. Pins of the Geneva pin wheel 96 can be made with different heights so that they do not interfere with the wall of slots of other Geneva pins. A portion of the rotation of the Geneva pin wheel 96 and Geneva slot wheel 97 be achieved using one or more partial circular gears and/or one or more partial non-circular gear in parallel. The partial gears generate the non-functional region of the rack velocity while the Geneva wheel system generates functional portion of the rack velocity. The Geneva wheel slots also have an overlap of the region generated by the partial gear. This is to achieve a 1:X ratio of rotation between Geneve pin wheel 96 and Geneva slot wheel 97. Here X is an integer or a reciprocal of an integer. Optionally, a one-way bearing can be placed between the circular or non-circular gear linking the Geneva slot wheel 97 to the partial driven gear. Depending on the scenario either the Geneva pin wheel 96 or the Geneva slot wheel 97 can be made driving or driven.
b) Scotch-Yoke-Module (
This Scotch-Yoke-Module comprises of:
The Input disk 102 has a radial slot.
The Slotted Rack holder 103 has a slot namely “Crank pin slot” 1013. It also has an extension on either side of the slot at the middle of the slot. This extension is normal to the Crank pin slot 1013. The Slotted rack holder 44, is placed on the other side of the Input disk 102 sandwiching the Input disk 102 between the Slotted Rack holder 103 and a Ratio-Changing-Mechanism, which is described in subsequent paragraphs. The Crank pin 101 passes through the slots of Ratio-Changing-Mechanism, Input disk 102, and Slotted Rack holder 103
The Rack 104 is attached to the Slotted Rack holder 103 normal to the Crank pin slot 1013 and paired with the Pinion 106. The Pinion 106 is mounted on a Shaft-Pinion 48. The computer-controlled clutch/one-way bearing/Ratchet-Mechanism 50 is mounted on the Shaft-Pinion 48. The Output-Gear/Output-Sprocket 51 is mounted on the OD of the One-Way-Bearing 50. Multiple pinions from multiple modules can be mounted on a common shaft-pinion 48. The one-way bearing can be placed between the pinion and the pinion shaft. In this scenario the shaft-pinion 48 will function as the CVT output. The shaft-pinion can be made hollow so that the CVT input shaft 100 can pass through the shaft-pinion 48 making the input and output of the CVT co-axial.
Two Rectifier-Modules are placed next to the Slotted Rack holder 103 such that the Rack 104 is placed normal to the Slotted rack holder's 44 Crank pin slot.
d) Gear-Changing-Mechanisms
Link Mechanism:
The Input shaft 100 has a non-circular hole in the middle. This is paired with a Sliding-Collar 108 with a matching exterior contour, which is co-axially placed allowing relative axial movement while restricting rotational angular displacement with respect to each other. Two thrust bearings 40 are co-axially placed in contact with one on either end of the Sliding-Collar 67 as shown in
For each scotch yoke module two Racks 64 can be placed on the Slotted Rack holder 103 with a phase shift of 180° engaged with their respective pinions placed co-axially on a common pinion shaft via a one-way bearing/computer-controlled clutch/a ratchet mechanism 114 to allow the pinion shaft to rotate in a specific direction. Many of these scotch yoke modules can be stacked and all the pinions of all the modules can be placed on one common pinion shaft, making the pinion shaft the output of the IVT. Further this common pinion shaft can be made hollow allowing the power shaft 121 which drives the driving Geneva pin wheel 96, to pass thru. With this arrangement a co-axial input to output can be achieved. This configuration allows to modify the output with a planetary gear system to achieve reverse gear converting the CVT to an IVT. This configuration also allows the force on the rack holder to pass through the plane of the common pinion shaft axis. In other words, the longitudinal axis of the common pinion and the force of the crankpin acting on the rack holder will be co-planer. This will minimize the moment of the force from the crank pin acting on the rack holder due to the resistance by the pinion and maximize the tangential force on the pinion.
Mechanism to Compensate Vibration (Rotational Imbalance):
1. Dummy-Crank pin 43: The Crank pin 101 is placed off-center when the Input disk 102 revolves. This imbalance will result in vibration. To compensate this, a Dummy-Crank pin 43 is placed at same distance 180° apart. This movement is identical to the movement of the Crank pin 101. The dummy crank pin 116 is attached to a dummy link 110 that links to the dummy crank pin 116 that is pivoted to the collar 108 placed to move in the opposite direction of the crank pin 101. The input shaft 100 is slotted to allow the link 109 and crank pin and dummy link 110 and dummy crank pin 116 to pass thru
2. Dummy-Rack 55 for counter oscillation: As the Input disk 102 rotates the Slotted Rack holder 103 has an oscillatory motion which will result in vibration. It is cancelled by having an appropriate mass oscillating in the opposite direction. This is achieved by pinion as shown in
Reverse Gear Mechanism:
When the output from the Pinion shaft 107 is coupled with Miter/Bevel Gear Differential input shaft 31. The Miter/Bevel Gear Differential output shaft 32 will rotate in opposite directions via Miter/Bevel Gear 33. The Miter/Bevel Gear Differential input shaft 31 of this differential-mechanism is placed co-axial with The Miter/Bevel Gear Differential output shaft 32 with clearance so that it is free to spin independently with respect to the Miter/Bevel Gear Differential input shaft 31. Two Clutch-Park/Neutral/Reverse clutch/dog clutch 35 with a clutch are placed on the Miter/Bevel Gear 33 allowing them to move axially. These can be made to link with either of the Miter/Bevel Gear 33, which rotate in opposite direction. When one of the collars 108 is made to link via the Clutch-Park/Neutral/Reverse clutch/dog clutch 35, by means of clutch, with a particular output Clutch-Park/Neutral/Reverse clutch/dog clutch 35 and the Miter/Bevel Gear Differential output shaft 31 will rotate in a particular direction. It will reverse its direction if the link 109 is swapped to the other Miter/Bevel Gear 33.
Neutral Gear Mechanism:
When the collars 108 are not in link via the Clutch-Park/Neutral/Reverse clutch/dog clutch 35 with any of the Miter/Bevel Gear 33, the collar 108 and the Miter/Bevel Gear Differential output shaft 32 are not restricted and, therefore, they are free to spin in any direction and function as a “neutral” gear.
Park Mechanism:
When the collars 108 are in link via the Clutch-Park/Neutral/Reverse clutch/dog clutch 35 with both the Miter/Bevel Gear 33, the collar 108 is restricted from spinning and the Miter/Bevel Gear Differential output shaft 32 is totally restricted and, therefore, they are restricted to spin in any direction and function as a “parking” gear.
Converting CVT to an IVT (Infinitely-Variable-Transmission):
Having a co-axial input and output allows the CVT to function as an IVT. This can be achieved by adding a Planetary gear system with a Sun-Gear, Ring-Gear and Planets supported by Carriers, and linking with Input shaft 100, the Co-Axial-Output-Element-With-Internal-Gear/Planetary gear 65.
The following are the options to achieve this:
In other words, The Co-Axial-Output-Element-With-Internal-Gear/Planetary gear 65 is connected to one of the three elements, either a Ring-Gear, a Carrier, or a Sun-Gear of a Planetary gear system. The Input shaft 100 is connected to one of the remaining two elements of the Planetary gear system. The third remaining element of the Planetary-System functions as the final output or wheel system 1022. This converts the CVT to an IVT.
Compensating for Deviation in Rack Movement with Cams:
It is beneficial to have smooth and gradual transitions in the rack movement profile to improve the life of the transmission. As shown in
1. gradual increase in acceleration from rest 1025
2. a region of acceleration 1026
3. gradual reduction in acceleration to a constant velocity 1027
4. a region of constant velocity 1028
5. gradual increase in deceleration to a constant deceleration 1029
6. a region of deceleration 1030
7. gradual reduction in deceleration to zero velocity 1031
8. steps 1 through 7 above repeated in the opposite direction
It may not always be possible to generate perfect Geneva wheel mechanism to meet the above desired Rack 104 movement. If the slot curves 1006 of the Geneva slot wheel 97 and the Geneva pin wheel 96 do not to achieve this desired Rack 104 movement, a planetary system can be used to compensate for any deviations from the desired Rack 104 movement profile. To achieve this, a Stationary sun gear 135 with respective to the ratio modifier frame 92 is placed co-axial with a driven circular or non-circular gear 132 which is driven by a driving circular or non-circular gear 131 as appropriate. This can also be used in addition to the Geneva wheel system. This is shown in
1. US non-provisional utility patent application Application Number: Ser. No. 16/395,219Title: Infinitely Variable Transmission with uniform input-to-output ratio that is non-dependent on friction2. PCT Application Application Number: PCT/US2019/041748Title: Pseudo Continuously Variable Transmission3. PCT Application Application Number: PCT/US2020/036636Title: Pseudo Continuously Variable Transmission with uninterrupted shifting4. PCT Application Application Number: PCT/US2021/017984Title: Infinitely Variable Transmission with uniform input-to-output ratio that is non-dependent on friction5. PCT Application Application Number: PCT/US2021/036266Title: Pseudo Continuously Variable Transmission with uninterrupted shifting
| Number | Date | Country | |
|---|---|---|---|
| Parent | PCT/US2019/041748 | Jul 2019 | US |
| Child | 17542482 | US | |
| Parent | PCT/US2020/036636 | Jun 2020 | US |
| Child | PCT/US2019/041748 | US | |
| Parent | PCT/US2021/017984 | Feb 2021 | US |
| Child | PCT/US2020/036636 | US | |
| Parent | PCT/US2021/036266 | Jun 2021 | US |
| Child | PCT/US2021/017984 | US | |
| Parent | 16395219 | Apr 2019 | US |
| Child | PCT/US2021/036266 | US |
