Patent Application
20180058517
The present disclosure relates generally to clutches for automotive transmissions and more particularly, relates to multiple bell cranks employed in the operation of such transmissions.
An automotive vehicle typically includes an internal combustion engine containing a rotary crankshaft configured to transfer motive power from the engine through a driveshaft to turn the wheels. A transmission may be interposed between the engine and driveshaft components to selectively control torque and speed ratios between the crankshaft and driveshaft. In a manually operated transmission, a corresponding manually operated clutch may be interposed between the engine and transmission to selectively engage and disengage the crankshaft from the driveshaft to facilitate manual shifting among available transmission gear ratios.
In the case of a manually operated transmission, a manually operated clutch may be positioned between the internal combustion engine and the transmission to selectively engage and disengage the crankshaft from the driveshaft in order to facilitate shifting through the available transmission gear ratios. Alternatively, in an automatically operated transmission, a plurality of automatically actuated clutch units may be adapted to dynamically shift through the available gear ratios without requiring operator intervention. In some embodiments, the plurality of clutch units or clutch systems may be incorporated within transmission systems to facilitate the shifting through the gear ratios.
Furthermore, the various gears may be structurally comprised of sun gears, intermediate gears, such as planet or pinion gears supported by carriers, and outer ring gears. Moreover, specific transmission clutches may be associated with specific sets of selectable gears within the transmission to facilitate the desired ratio changes.
An exemplary transmission clutch system that is associated with first and reverse gear ratios may be positioned near the front of the transmission and closely adjacent to the engine crankshaft. The clutch may have a driving member and a driven member disposed circumferentially about the driving member and the driving and driven members may be configured to operate in multiple modes. Furthermore, in one non-limiting example, the driving member may be drivingly rotatable in only one direction. Alternatively or additionally, the driving member may be drivingly rotatable in a plurality of directions, however other modes and rotations may be possible. Moreover, the driving member may be selectively locked to the driven member via an engagement mechanism such as a roller, a sprag, a pawl, or other known engagement mechanisms. The rotation of the driving member may be effective to directly transfer rotational motion from the engine to the driveline.
In some transmission systems, the driven member may be fixed to an internal case or housing of an associated planetary member of the transmission. Under such circumstances, in a first configurational mode the driving member may need to be adapted to drive in one rotational direction, but freewheel, or overrun, in the opposite direction. Those skilled in the art will appreciate that overrunning may be particularly desirable under certain operating states, for example when a machine is traveling downhill or coasting. Under such a condition, the driven member may occasionally have a tendency to rotate faster than its associated driving member. Therefore, allowing the driving member to overrun the driven member may help provide protection against damage to the engine and/or transmission components.
In a second mode, such as when a machine may be in reverse gear, the engagement mechanisms may be adapted for actively engaging in both rotational directions of the driving member, thus not allowing for an overrunning condition in either direction. Alternatively, in a third mode the engagement mechanisms may be adapted such that they are disengaged in both rotational directions of the driving member and therefore allowing rotation in either direction.
Transmission systems may include a plurality of gear sets to accommodate multiple gear ratios, and therefore the reliability of actuators and other transmission components used for automatically switching clutch modules between and/or among various available operating modes is a consistent design concern. As a result, much effort has been directed to finding ways to assure transmission reliability at competitive costs.
In accordance with one aspect of the present disclosure a multi-mode clutch system is disclosed. The multi-mode clutch system may include an actuator and a first bell crank and a second bell crank that are operatively associated with the actuator. Furthermore, the first and second bell cranks may rotate about a first and second pivot point upon a movement of the actuator. The multi-mode clutch system may further comprise a first pawl and a second pawl wherein the first bell crank acts on the first pawl and the second bell crank acts on the second pawl. Moreover, the multi-mode clutch system may be configured to allow multiple modes of operation for engagement and disengagement between the first and second pawls and driving member according to different actuator positions.
In accordance with another aspect of the present disclosure a multi-mode clutch system with a first bell crank and a second bell crank is disclosed. The multi-mode clutch system may be configured to include an actuator and an armature. The multi-mode clutch system may also include a bracket that is fixedly attached to the actuator and the bracket may have a first pivot point and a second pivot point. Moreover, the first bell crank may be pivotally associated with the first pivot point and the second bell crank may be pivotally associated with the second pivot point and the first and second bell cranks may rotate about the first and second pivot points. The multi-mode clutch system may further include a first pawl and a second pawl wherein the first bell crank and the second bell crank may be respectively configured to act on the first and second pawls to allow for multiple modes of operation for engagement and disengagement between the first and second pawls and an driving member according to different actuator positions.
In accordance with yet another aspect of the present disclosure a method of operating a multi-mode clutch system having a first bell crank and a second bell crank may be configured to interact with a driving member to selectively provide multiple modes of operation is disclosed. The method may include forming an actuator having an armature and a pin and associating the actuator with the first and second bell cranks. Moreover, the first and second bell cranks may respectfully rotate about a first and second pivot point upon movement of the actuator. The method may further include, positioning a first pawl and a second pawl such that the first bell crank acts on the first pawl and the second bell crank acts on the second pawl. Furthermore, the actuator may be configured to selectively control multiple actuator movements on the first and second pawls to produce multiple modes of operation of the clutch system.
These and other aspects and features will be better understood when reading the following detailed description in conjunction with the accompanying drawings.
For further understanding of the disclosed concepts and embodiments, reference may be made to the following detailed description, read in connection with the drawings, wherein like elements are numbered alike, and in which:
It is to be noted that the appended drawings illustrate only typical embodiments and are therefore not to be considered limiting with respect to the scope of the disclosure or claims. Rather, the concepts of the present disclosure may apply within other equally effective embodiments. Moreover, the drawings are not necessarily to scale, emphasis generally being placed upon illustrating the principles of certain embodiments.
Turning now to the drawings, and with specific reference to
A bracket 26 may be attached to the actuator 14, and may include a slot 30. The pin 22 may be positioned in the slot 30, and may travel along a portion of the slot 30 as it is moved by the actuator 14. The bracket 26 may further include first and second pivot points 34, 38. A first bell crank 42 may pivot about the first pivot point 34, and a second bell crank 46 may pivot about the second pivot point 38. The first bell crank 42 may include a first pawl arm 50 and a first pin arm 54, while the second bell crank 46 may include a second pawl arm 58 and second pin arm 62. Additionally, the first bell crank 42 may include a first actuation point 66 and the second bell crank 46 may include a second actuation point 70. In one non-limiting example, the pin 22 is configured to interact with each of the first and second actuation points 66, 70 such that the interaction between the pin 22 and first and second actuation points 66, 70 produce the necessary movement of the first and second bell cranks 42, 46 for the desired engagement of the pawls 86, 90 and driving member 74. While, one non-limiting example is illustrated, other configurations of the pin 22 and first and second actuation points 66, 70 may be used depending upon the desired direction of motion and travel for the first and second bell cranks 42, 46. Furthermore, a bell crank return spring 72 may be incorporated to help bias the first and second bell cranks 42, 46 towards the actuator 14.
The multi-mode clutch system 10 may also include a driving member 74 rotatable around a rotation point 78. The driving member 74 may include a series of notches 82. A first pawl 86 and a second pawl 90 may be attached to the bracket 26, and may rotate about first and second pawl pivot points 94, 98 respectively. The pawls 86, 90 may rotate between open and locked positions. An open position may allow driving member 74 rotation in both directions, or in a particular direction, which may also be referred to as a ratcheting position. Additionally or alternatively, while in a locked position the driving member 74 rotation may not be allowed to rotate in a particular direction due to interference between one of the pawls 86, 90 and the notches 82. Moreover, a first pawl spring 102 may bias the first pawl 86 towards the locked position, and a second pawl spring 106 may bias the second pawl 90 towards the locked position.
More specifically, the first pawl 86 may include a first heel 110 and a first toe 114, and the second pawl 90 may include a second heel 118 and a second toe 122. Each heel 110, 118 may be actuated by respective bell cranks 42. 46 during operation, and each toe 114, 122 may be biased towards the locked position by each respective pawl spring 102, 106. Further, each toe 114, 122 may interfere with the notches 82 in a pawl 86, 90 locked position, thus preventing driving member 74 rotation in a direction.
In operation, the actuator 14 may move the armature 18 into various positions. In one embodiment, three positions are described, however a fewer or greater number of actuator 14 and/or armature 18 positions are possible. The multi-mode clutch system 10 may be arranged in such a way that different actuator 14 positions have different effects on the pawl 86, 90 positions. In the shown embodiment, at least three different actuator 14 positions allow for at least three different pawl 86, 90 positions and combinations, however a different number of positions is possible. Each actuator 14 position may correspond with a different clutch mode of operation for engagement and disengagement between the pawls 86, 90 and the driving member 74. While three actuator 14 positions are shown to correspond to three different modes of clutch operation, additional actuator 14 positions are possible which may produce additional modes of clutch operation.
In one position, as shown in
In another position, as shown in
In yet another position, as shown in
A variety of approaches may be used to enable the multi-mode clutch system 10 to achieve multiple operating modes corresponding to different actuator 14 settings. As described above, three operating modes are illustrated to provide a set of non-limiting examples of the multi-mode clutch system 10, however additional modes of operation are possible. For example, the three or more operating modes could be achieved by varying the lengths (52, 60) of the first and second pawl arms 50, 58, or by varying the lengths (56, 64) of the first and second pin arms 54, 62. Alternatively, a combination of pawl arm 50, 58 and pin arm 54, 62 lengths (52, 54, 60, 64) could achieve multi-mode ability. Furthermore, the locations of the first and second pivot points 34, 38, or the first and second pawl pivot points 94, 98, or the relative locations thereof, may be configured to achieve multi-mode capability. Additionally, the shape, orientation or size of the pawls 86, 90 could be configured to enable multi-mode operation. Furthermore, each of the above-mentioned variables may be altered relative to each other to achieve additional modes of operation.
Referring now to
If the first mode of operation (92) is not desired then the determination may be evaluated in block 142 whether the second mode of operation (96) is desired. If the second mode of operation (96) is selected, then in block (146) the actuator (14) may be moved to position both pawls (86, 90) in a locked position. In one-non limiting example,
It is to be understood that the foregoing is a description of one or more embodiments of the invention. However, the invention is not limited to the particular embodiment(s) disclosed herein. Furthermore, the statements contained in the foregoing description relate to particular embodiments and are not to be construed as limitations on the scope of the invention or on the definition of terms used in the claims, except where a term or phrase is expressly defined above. Various other embodiments and various changes and modifications to the disclosed embodiment(s) will become apparent to those skilled in the art. All such other embodiments, changes, and modifications are intended to come within the scope of the appended claims.
In general, the multi-mode clutch system with dual bell cranks of the present disclosure may be applied on a variety of industrial applications, including but not limited to, automobiles, trucks, vans, off-road vehicles, agriculture equipment, construction equipment, and other equipment of the type incorporating internal combustion engines, automatic transmissions, and drivelines.
As disclosed herein, the multi-mode clutch system may incorporate an actuator having an armature that may be configured to interact with dual bell cranks. Furthermore, the actuator and the slotted dual bell cranks guided by a slot in a bracket may be configured to actuate a set of pawls. The multi-mode clutch system may allow for the translation of the linear motion provided by the actuator to engage and/or disengage the pawls into multiple modes on the clutch device. In some embodiments, springs may be utilized to aid with engagement and retraction of the pawls depending on the desired clutch mode. During operation, using the actuator and dual bell cranks in accordance with the present disclosure may create several non-limiting effects on the pawls. For example, in one mode of operation one of the pawls may be placed in an open mode and the other pawl may be positioned in a locked mode. As a result the multi-mode clutch system may be free to rotate in one direction and unable to rotate in the other direction. In another mode, it may be possible to place both pawls in a locked mode and as a result the multi-mode clutch system may restrict rotation in either direction. In yet another mode, both pawls may be positioned in an open position allowing the multi-mode clutch system to rotate, or freewheel, in either direction. While three separate modes are disclosed, additional modes of operation are certainly possible.
This application is an International Patent Application claiming priority to US 35 U.S.C. § 119(e) to U.S. Provisional Patent Application No. 62/147,448 filed on Apr. 14, 2015.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/US2016/026388 | 4/7/2016 | WO | 00 |
| Number | Date | Country | |
|---|---|---|---|
| 62147448 | Apr 2015 | US |
