The present disclosure relates to a system for transmitting torque, and more particularly to a system for transmitting torque with speed modulation between a motor generator and an engine.
Conventional systems employed for starting of an engine by a motor generator may include, for example, a Bendix drive or some planetary gear drives disposed therebetween. These systems may modulate torque and/or speed during transmission of power between the engine and the motor generator.
A large torque may typically be required to crank the engine and accomplish starting thereof. Once the engine is up and running, the motor generator may be configured to generate power. During this power generation phase, it may be helpful to keep the speed of the motor generator at an optimum level, and some previously known systems may be configured to modulate torque and/or speed depending on the operating modes. These previously known systems may be characterized by a variety of limitations and disadvantages. For example, many starter generator systems may be unable provide adequate electricity production/torque capabilities. In addition, many known systems may include costly and complex components which may be unreliable and susceptible to failure. Furthermore, many known starter generator systems and the components associated therewith may lack compactness and versatility in terms of mountings and connections to other components.
GB430044A discloses a power-transmission mechanism applicable for a turning-gear of an engine. The power transmission mechanism includes two linearly aligned shafts. One of the linearly aligned shafts may be that of a dynamo-electric machine and the other may be coupled to an engine shaft directly or through the camshaft or timing gear. The shafts are automatically coupled either directly or through reduction gearing according as one or other shaft is the driving shaft via a floating clutch ring slidably splined on the engine shaft has oppositely facing radial ratchet teeth on its lateral surfaces, for engagement respectively with corresponding teeth on a disc integral with a pinion mounted directly on the dynamo-electric machine shaft, and on a gear wheel connected to the dynamo-electric machine shaft through gearing. The dynamoelectric machine can be used as a motor to drive the engine through the reduction gearing for starting purposes and is then driven directly at engine speed as a generator wherein when the dynamo-electric machine shaft is the driver, the ring is forced by the inclined faces of the ratchet teeth into engagement with the clutch teeth of the gear, and when the engine starts and the engine shaft drives, the ring is forced into engagement with the teeth on the pinion. The present disclosure is directed to mitigating or eliminating one or more of the drawbacks discussed above.
In one aspect, the present disclosure provides a system for transmitting torque with speed modulation between a motor generator and an engine. The system includes a first shaft, a second shaft, a first reduction gearset, and a second reduction gearset. The first shaft is configured to rotatably connect with the motor generator. The second shaft is configured to rotatably connect with the engine. The first reduction gearset is rotatably supported at least in part on the first shaft. The first reduction gearset is disposed in selective engagement with the first shaft via a first overrunning clutch disposed therebetween. The second reduction gearset is rotatably supported at least in part on the first shaft and at least in part on the second shaft. The second reduction gearset is disposed in selective engagement with the first shaft via a second overrunning clutch disposed therebetween.
In another aspect, the present disclosure provides a system for transmitting torque with speed modulation between a motor generator and an engine. The system includes a first shaft, a second shaft, a first reduction gearset, and a second reduction gearset. The first shaft is configured to rotatably connect with the motor generator. The second shaft is configured to rotatably connect with the engine. The first reduction gearset is rotatably supported at least in part on the first shaft. The first reduction gearset is disposed in selective engagement with the first shaft via a first overrunning clutch disposed therebetween. The second reduction gearset is rotatably supported at least in part on the first shaft and at least in part on the second shaft. The second reduction gearset is disposed in selective engagement with the first shaft via a second overrunning clutch disposed therebetween. When the first overrunning clutch is engaged and the second overrunning clutch is disengaged, the first shaft is operable to transmit torque to the second shaft via the first and second reduction gearsets in tandem. When the first overrunning clutch is disengaged and the second overrunning clutch is engaged, the second shaft is operable to transmit torque to the first shaft via the second reduction gearset.
In another aspect, the present disclosure provides a method of transmitting torque with speed modulation between a motor generator and an engine. The method includes rotatably connecting a first shaft with the motor generator. The method further includes rotatably supporting a first reduction gearset and a second reduction gearset at least in part on the first shaft. The method further includes rotatably connecting a second shaft with the engine. The method further includes rotatably supporting the second reduction gearset at least in part on the second shaft. The method further includes selectively engaging and disengaging the first reduction gearset and the second reduction gearset with the first shaft while transmitting torque between the first shaft and the second shaft.
Other features and aspects of this disclosure will be apparent from the following description and the accompanying drawings.
The present disclosure relates to a system for transmitting torque with speed modulation between a motor generator and an engine. Wherever possible the same reference numbers will be used throughout the drawings to refer to same or like parts.
The exemplary motor generator 101 depicted in
The system 104 includes a first shaft 106, a second shaft 108. The first shaft 106 can be configured to rotatably connect with the motor generator 101. The second shaft 108 can be configured to rotatably connect with the engine 102. In one embodiment, the first shaft 106 which can be connected to rotatably transmit mechanical energy between the system 104 and the motor generator 101 can be spaced in parallel offset relation with respect to the second shaft 108 which can be connected to rotatably transmit mechanical energy between the system 104 and the engine 102. Additionally, in one embodiment, the second shaft 108 can be connected to a starting gear (not shown) of the engine 102. For example, the starting gear may be a gear connected to the flywheel of the engine 102. In another example, the starting gear may be a gear disposed on the camshaft of the engine. Accordingly, the second shaft 108 can be connected to the starting gear of the flywheel or the camshaft (not shown) of the engine 102. However, it is to be noted that a location or operating part of the engine 102 to which the second shaft 108 of the present system 104 is connected may vary depending on design constraints and/or specific requirements of an application.
The system 104 further includes a first reduction gearset 110 rotatably supported at least in part on the first shaft 106. The first reduction gearset 110 is disposed in selective engagement with a second reduction gearset 124 via a first overrunning clutch 112 disposed therebetween. In an embodiment as shown, the first reduction gearset 110 can include a first gear 114 and a second gear 116 rotatably supported on the first shaft 106. The first gear 114 can be fixedly and rotatably coupled to the first shaft 106 to rotate in unison therewith, and the second gear 116 can be rotatably mounted on first shaft 106 to rotate independently of the first shaft 106 via bearings 115. Further, the first reduction gearset 110 can include an intermediate shaft 118 parallelly offset from the first shaft 106, a first reduction gear 120, and a second reduction gear 122. The first reduction gear 120 and the second reduction gear 122 are fixedly and rotatably attached to the intermediate shaft 118 such that the first reduction gear 120, the second reduction gear 122, and the intermediate shaft 118 can rotate in unison. The first reduction gear 120 is disposed in intermeshing rotatable engagement with the first gear 114. The second reduction gear 122 is disposed in intermeshing rotatable engagement with the second gear 116.
In an embodiment as shown in
With continued reference to
The first and second overrunning clutches 112, 126, disclosed herein, are of a one-way freewheeling type. As illustrated in the exemplary embodiment of
Detailed explanation to a manner of operation of the first and second overrunning clutches 112, 126 will be made hereinafter.
With reference to
In particular, as shown in
In a first mode of operation, the first overrunning clutch 112 engages when the second gear 116 (as rotated by first shaft 106 via first gear 114, first reduction gear 120, and second reduction gear 122) rotates faster than the third gear 128 (i.e. speed of the interconnecting element 136a is greater than a speed of the interconnecting element 136b). Therefore, engagement of the first overrunning clutch 112 engages the first reduction gearset 110 to the second reduction gearset 124 via interconnecting elements 136a, 136b located between the second gear 116 and the third gear 128. Moreover, the second overrunning clutch 126 simultaneously disengages with engagement of the first overrunning clutch 112 when the first shaft 106 rotates faster than the third gear 128 and the interconnecting element 136b. This disengagement of the second overrunning clutch 126 renders the third gear 128 in the freewheeling mode with respect to the first shaft 106 i.e. the second reduction gearset 124 is rendered free from direct torque of the first shaft 106.
Thereafter, the first shaft 106 is operable to transmit torque to the second shaft 108 via the first and second reduction gearsets 110, 124 in tandem. The engagement and disengagement, of the first overrunning clutch 112 and the second overrunning clutch 126 respectively, allows torque from the motor generator 101 to be routed via the first shaft 106, the first reduction gearset 110, and the second reduction gearset 124 before being transmitted to the engine 102. In this mode of operation, the torque at the second shaft 108 i.e. torque transmitted to the engine 102 is greater than the torque at the first shaft 106. Therefore, the first mode of operation, as disclosed herein, can be beneficially implemented by the system 104 during startup of the engine 102 by the motor generator 101.
It is to be noted that the engagement and disengagement of the first overrunning clutch 112 and the second overrunning clutch 126, disclosed from the first mode of operation, occur simultaneously or at least in a substantially concurrent manner i.e. with minimum overlap in time duration. Further, the first overrunning clutch 112 and the second overrunning clutch 126 continue to remain in their engaged and disengaged state respectively until the speed of the third gear 128 remains less than a speed of the first shaft 106 (i.e. speed of the motor generator 101) and a speed of the second gear 112. As evident to one skilled in the art, the speed of the third gear 128 in this mode of operation can increase with increasing speeds of the second shaft 108 (engine crankshaft speed) and the shaft 134 before the engine 102 has initialized or started.
In a second mode of operation, the first overrunning clutch 112 disengages when the third gear 128 (as rotated by engine crankshaft via second shaft 108, second idler gear 132b, and first idler gear 132a) rotates faster than the second gear 116 (i.e. speed of interconnecting element 136b is now greater than a speed of interconnecting element 136a). Disengagement of the first overrunning clutch 112 renders the first reduction gearset 110 to be in the freewheeling mode with respect to the second reduction gearset 124 i.e. the interconnecting element 136a and hence, the first reduction gearset 110 will no longer receive torque directly from the interconnecting element 136 and the second reduction gearset 124. Moreover, the second overrunning clutch 126 simultaneously engages with disengagement of the first overrunning clutch 112 when the third gear 128 rotates faster (from the increased speed of the second shaft 108 and the engine crankshaft) than the first shaft 106. This engagement of the second overrunning clutch 126 engages the second reduction gearset 124 to the first shaft 106 via interconnecting element 136b located therebetween.
Thereafter, the second shaft 108 is operable to transmit torque to the first shaft 106 via the second reduction gearset 124 alone. The engagement and disengagement, of the second overrunning clutch 126 and the first overrunning clutch 112 respectively, allows torque from the engine 102 to be routed via the second reduction gearset 124, and the first shaft 106 before being transmitted to the motor generator 101. In this mode of operation, a rotational speed of the first shaft 106 is increased when the first overrunning clutch 112 disengages and the second overrunning clutch 126 engages. Therefore, this mode of operation can be beneficially implemented by the system 104 during a power generation mode at the motor generator 101 after the engine 102 has initialized or started. However, the rotational speed of the first shaft 106 may be beneficially increased in a range of about 1.1 to 3.5 times that of a rotational speed of the first shaft 106 during startup (i.e. from first mode of operation of the system 104).
With continued reference to
It is envisioned by way of the present disclosure that in the second mode of operation by the system 104, the engagement of the second overrunning clutch 126 and the disengagement of the first overrunning clutch 112 can be helpful in preventing the motor generator 101 from running at a very large speed due to speed amplification from the first and second reduction gearsets 110, 124. Rather, only the second overrunning clutch 126 engages the second reduction gearset 124 to the first shaft 106 and hence, amplification in the speed of the first shaft 106 is effected by the gear ratios of the second reduction gearset 124 alone. Thus, the speed of the first shaft 106 marginally increases from that during startup of the engine 102 (i.e. when the system 104 was executing the first mode of operation disclosed herein).
In an example, if the first gear 114, the first reduction gear, the second reduction gear, and the second gear 116 of the first reduction gearset 110 have 25 teeth, 60 teeth, 18 teeth, and 67 teeth respectively, and similarly, if the third gear 128, the first idler gear 132a, the second idler gear 132b, and the fourth gear 130 of the second reduction gearset 124 have 70 teeth, 22 teeth, 22 teeth, and 126 teeth respectively, then the effective torque amplification in the first mode of operation may be given by G1=((60÷25)×(67÷18)×(126÷70))=16.08 (i.e. effective gear reduction in the first mode of operation is approximately 1:16). However, the effective speed amplification or increase in speed of the first shaft 106 during the second mode of operation by the system 104 may be given by G2=(126÷70)=1.8 (i.e. effective gear reduction in the first mode of operation is 1:1.8). Therefore, with reference to the preceding example, during engine startup, the system 104 can be in the first mode of operation and can apply a large torque from the motor generator 101 (16 times that of the motor generator 101) to the starting gear, flywheel, or camshaft of the engine 102. However, during power generation at the motor generator 101, the system 104 can be in the second mode of operation and can increase the speed of the first shaft 106 by 1.8 times (as compared to a rotational speed of the first shaft 106 during startup of the engine 102).
With reference to the present disclosure, the speed of the first shaft 106 during power generation may be increased in order to achieve maximum and/or optimum power output from the motor generator 101. Although, the preceding example discloses a 1.8 times increase in the speed of the first shaft 106 (as compared to a rotational speed of the first shaft 106 during startup of the engine 102), the increase in speed can be varied by varying the gear ratio between the third and fourth gears 128, 130. However, it is envisioned to beneficially keep the increase in speed of the first shaft 106 within a certain limit to avoid running the motor generator 101 at very high rpm (revolutions per minute). Therefore, in various embodiments of the present disclosure, the increase in rotational speed of the first shaft 106 during the second mode of operation may be kept at about 1.1 to 3.5 times that of the rotational speed of the first shaft 106 in the first mode of operation.
With continued reference to
Referring now to
Referring to
Although it is disclosed in conjunction with the embodiment of
Turning back to
With continued reference to
Although the foregoing disclosure discloses omission of the idler gearset 132 and the shaft 134 from the system 104 of
Although, exemplary angular values such as 90 degrees, 180 degrees, 270 degrees have been used to explain and demonstrate the various embodiments of the present disclosure, the angular values disclosed herein are merely exemplary in nature and non-limiting of this disclosure. In other embodiments, the angular value between the first portion 406 and the second portion 408 may change depending on specific requirements of an application. For example, the housing 200 can be constructed with the first portion 406 and the second portion 408 turned 125 degrees or 175 degrees relative to each other.
In a further aspect of the present disclosure, when constructing the housing 200, any direction of rotation can be implemented to the first portion 406 and/or the second portion 408 depending on various requirements of an application. In one embodiment, the housing 200 can be constructed with the second portion 408 turned clockwise to 125 degrees with respect to the first portion 406. In another embodiment, the second portion 408 can be turned counterclockwise to 125 degrees with respect to the first portion 406. Therefore, the first portion 406 and the second portion 408 can be suitably oriented to adapt the housing 200 for fitment and/or installation at a particular location.
At step 1010, the method 1000 further includes selectively engaging and disengaging the first reduction gearset 110 and the second reduction gearset 124 with the first shaft 106 while transmitting torque between the first shaft 106 and the second shaft 108. In one embodiment, the method 1000 includes engaging the first reduction gearset 110 and disengaging the second reduction gearset 124 such that the first shaft 106 can be operable for transmitting torque to the second shaft 108 via the first and second reduction gearsets 110, 124 in tandem. In another embodiment, the method 1000 includes disengaging the first reduction gearset 110 and engaging the second reduction gearset 124 such that the second shaft 108 can be operable for transmitting torque to the first shaft 106 via the second reduction gearset 124.
Although, some previously known systems modulated torque and/or speed during various operating modes of the engine 102 and the motor generator 101, such previously known systems were less robust in construction and hence, prone to operational fatigue under heavy loads. Such systems when constructed for implementation in heavy-duty applications were expensive and of less reliability in operation. Moreover, the previously known systems were typically bulky and may be cumbersome to install in tight or compact spaces.
With implementation of the present disclosure, the housing 200 disclosed herein can be split into the first portion 406 and the second portion 408. Moreover, during manufacture of the system 104, the first portion 406 can be oriented and fixed in any angular position with respect to the second portion 408 such that the overall housing 200 is adapted to fit within limited spaces that are typically available between the engines and motor generators. Moreover, during manufacture of the system 104, an offset distance between the first shaft 106 and the intermediate shaft 118, the shaft 134, or the second shaft 108 is adjusted, and thereafter, a size of the housing 200 is fixed to accommodate all the components therein. The housing 200 may be rendered in a compact size if the amounts of respective offset distance present between the various shafts 106, 118, 134, and 108 are reduced. Therefore, the present configuration of the housing 200 and/or the system 104, and the flexibility in design thereof allows easy installation of the housing 200 in locations with tight space constraints.
Further, the operation of the present system 104 is effected by the selective engagement and disengagement of the first and second overrunning clutches 112, 126. Therefore, the present system 104 may do away with use of actuating assemblies that were previously installed for use in conjunction with conventional systems. Consequently, the present system 104 can be robust and hence, less prone to operational fatigue under heavy loads. Therefore, the system 104 of the present disclosure may have an improved or prolonged service life as compared to conventionally known systems. Moreover, the present system 104 can be easy and less expensive to manufacture when constructed for heavy-duty applications.
While aspects of the present disclosure have been particularly shown and described with reference to the embodiments above, it will be understood that various additional embodiments may be contemplated by the modification of the disclosed machine, systems and methods without departing from the spirit and scope of what is disclosed. Such embodiments should be understood to fall within the scope of the present disclosure as determined based upon the claims and any equivalents thereof.
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Number | Date | Country | |
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20150233448 A1 | Aug 2015 | US |