OVERRUNNING COUPLING AND CONTROL ASSEMBLY, COUPLING ASSEMBLY AND LOCKING MEMBER FOR USE THEREIN HAVING IMPROVED DYNAMICS WITH REGARDS TO LOCKING MEMBER LAYDOWN SPEED

Abstract

Overrunning coupling and control assembly, coupling assembly and locking member having at least one side surface with a draft to improve locking member dynamics are provided. Locking member dynamics is improved with regards to locking member laydown speed. Laydown speed variation cause by a variable frictional coefficient between a pocket surface of a pocket in which the locking member is received and nominally retained and the at least one side surface of the locking member is minimized as well.

Claims

1. A locking member for controllably transmitting torque between first and second coupling members of a coupling assembly, the first coupling member including a coupling face having a pocket which is at least partially defined by a pocket surface, the pocket being sized and shaped to receive and nominally retain the locking member, the locking member laying down in the pocket during an overrunning condition of the assembly at a laydown angular velocity of the first coupling member about a rotational axis of the assembly, the locking member comprising: at least one side surface which slidably contacts the pocket surface during locking member laydown; a member-engaging first end surface; a member-engaging second end surface; an elongated main body portion between the end surfaces; and at least one projecting pivot which extends laterally from the main body portion for enabling pivotal motion of the locking member during locking member laydown, the end surfaces of the locking member being movable between engaged and disengaged positions with respect to the coupling members during the pivotal motion whereby one-way torque transfer may occur between the coupling members and wherein the at least one side surface has a draft with a draft angle to improve locking member dynamics with regards to locking member laydown speed and to minimize laydown speed variation caused by a variable frictional coefficient between the pocket surface and the at least one side surface.

2. The locking member as claimed in claim 1, wherein the locking member is a locking strut.

3. The locking member as claimed in claim 2, wherein the locking strut is a passive locking strut.

4. The locking member as claimed in claim 3, wherein the draft angle is in a range of 0.0 to 30.

5. The locking member as claimed in claim 2, wherein the locking strut is an active locking strut.

6. The locking member as claimed in claim 5, wherein the draft angle is in a range of 5 to 30.

7. The locking member as claimed in claim 1, wherein the main body portion has front and rear side surfaces having drafts.

8. The locking member as claimed in claim 7, wherein the drafts of the front and rear side surfaces are the inverse of one another.

9. The locking member as claimed in claim 1, wherein the at least one pivot includes a side surface having the draft.

10. The locking member as claimed in claim 1, wherein the locking member includes inner and outer pivots which extend laterally from the main body portion.

11. An engageable coupling assembly comprising: first and second coupling members, the first coupling member including a coupling face having a pocket which is at least partially defined by a pocket surface, the pocket being sized and shaped to receive and nominally retain a locking member, the locking member laying down in the pocket during an overrunning condition of the assembly at a laydown angular velocity of the first coupling member about a rotational axis of the assembly, the locking member including: at least one side surface which slidably contacts the pocket surface during locking member laydown; a member-engaging first end surface; a member-engaging second end surface; an elongated main body portion between the end surfaces; and at least one projecting pivot which extends laterally from the main body portion for enabling pivotal motion of the locking member during locking member laydown, the end surfaces of the locking member being movable between engaged and disengaged positions with respect to the coupling members during the pivotal motion whereby one-way torque transfer may occur between the coupling members and wherein the at least one side surface has a draft with a draft angle to improve locking member dynamics with regards to locking member laydown speed and to minimize laydown speed variation caused by a variable frictional coefficient between the pocket surface and the at least one side surface.

12. The assembly as claimed in claim 11, wherein the locking member is a locking strut.

13. The assembly as claimed in claim 12, wherein the locking strut is a passive locking strut.

14. The assembly as claimed in claim 13, wherein the draft angle is in a range of 0.0 to 30.

15. The assembly as claimed in claim 12, wherein the locking strut is an active locking strut.

16. The assembly as claimed in claim 15, wherein the draft angle is in a range of 5 to 30.

17. The assembly as claimed in claim 11, wherein the main body portion has front and rear side surfaces having drafts.

18. The assembly as claimed in claim 17, wherein the drafts of the front and rear side surfaces are the inverse of one another.

19. The assembly as claimed in claim 11, wherein the at least one pivot includes a side surface having the draft.

20. The assembly as claimed in claim 11, wherein the locking member includes inner and outer pivots which extend laterally from the main body portion.

21. An overrunning coupling and control assembly comprising: first and second coupling members, the first coupling member including a first coupling face having a pocket which is at least partially defined by a pocket surface, the pocket being sized and shaped to receive and nominally retain a locking member and a second coupling face having a passage in communication with the pocket to communicate an actuating force to the locking member to actuate the locking member within the pocket so that the locking member moves between engaged and disengaged positions, the locking member laying down in the pocket during an overrunning condition of the assembly at a laydown angular velocity of the first coupling member about a rotational axis of the assembly, the locking member including: at least one side surface which slidably contacts the pocket surface during locking member laydown; a member-engaging first end surface; a member-engaging second end surface; an elongated main body portion between the end surfaces; and at least one projecting pivot which extends laterally from the main body portion for enabling pivotal motion of the locking member during locking member laydown, the end surfaces of the locking member being movable between engaged and disengaged positions with respect to the coupling members during the pivotal motion whereby one-way torque transfer may occur between the coupling members and wherein the at least one side surface has a draft with a draft angle to improve locking member dynamics with regards to locking member laydown speed and to minimize laydown speed variation caused by a variable frictional coefficient between the pocket surface and the at least one side surface.

22. The assembly as claimed in claim 21, wherein the locking member is a locking strut.

23. The assembly as claimed in claim 22, wherein the locking strut is a passive locking strut.

24. The assembly as claimed in claim 23, wherein the draft angle is in a range of 0.0 to 30.

25. The assembly as claimed in claim 22, wherein the locking strut is an active locking strut.

26. The assembly as claimed in claim 25, wherein the draft angle is in a range of 5 to 30.

27. The assembly as claimed in claim 21, wherein the main body portion has front and rear side surfaces having drafts.

28. The assembly as claimed in claim 27, wherein the drafts of the front and rear side surfaces are the inverse of one another.

29. The assembly as claimed in claim 21, wherein the at least one pivot includes a side surface having the draft.

30. The assembly as claimed in claim 21, wherein the locking member includes inner and outer pivots which extend laterally from the main body portion. -

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0055] FIG. 1 is a top plan view, partially broken away, of a prior art locking member or strut located in a pocket of a rotating pocket plate together with a pivot axis of the strut, different reactive forces, F.sub.R1 and F.sub.R2, and a centrifugal force F.sub.CG at a center of gravity of the strut;

[0056] FIG. 2 is a view similar to the view of FIG. 1 of a different prior art locking member and different moment arms;

[0057] FIG. 3 is an exploded perspective view of a first embodiment of a passive coupling assembly constructed in accordance with the invention;

[0058] FIG. 4 is a view similar to the view of FIG. 3 but from a reverse angle;

[0059] FIG. 5 is a view similar to the view of FIG. 3 showing a second embodiment of a passive coupling assembly;

[0060] FIG. 6 is a view similar to the view of FIG. 5 but from a reverse angle;

[0061] FIG. 7 is a view similar to the view of FIG. 3 of a first embodiment of an active coupling assembly constructed in accordance with the invention;

[0062] FIG. 8 is a view similar to the view of FIG. 7 but from a reverse angle;

[0063] FIG. 9 is a view similar to the view of FIG. 5 showing a second embodiment of an active coupling assembly;

[0064] FIG. 10 is a view similar to the view of FIG. 9 but from a reverse angle;

[0065] FIG. 11 is a top perspective view of a first embodiment of a locking member constructed in accordance with the present invention;

[0066] FIG. 12 is a back end view of the locking member of FIG. 11;

[0067] FIG. 13 is a top plan view of the locking member of FIG. 11;

[0068] FIG. 14 is a front end view of the locking member of FIG. 11;

[0069] FIG. 15 is a side elevational view of the locking member of FIG. 11;

[0070] FIG. 16 is a view similar to the view of FIG. 11 but of a second embodiment of the locking member;

[0071] FIG. 17 is a view similar to the view of FIG. 13 but of the second embodiment;

[0072] FIG. 18 is a view similar to the view of FIG. 14 but of the second embodiment;

[0073] FIG. 19 is a view similar to the view of FIG. 15 but of the second embodiment;

[0074] FIG. 20 is a view, partially broken away and in cross section, of a passive coupling assembly with the locking member of FIG. 16 extending through an aperture of a cover plate between pocket and notch plates;

[0075] FIG. 21 is a view similar to the view of FIG. 20 but with the locking member in its laid down position;

[0076] FIG. 22 is a view similar to the view of FIG. 20 but including arrows which represent various forces;

[0077] FIG. 23 is a view similar to the view of FIG. 21 but including arrows which represent various forces;

[0078] FIG. 24 is a graph of draft angle versus laydown speed (RPM) for a passive locking member with a variable frictional coefficient;

[0079] FIG. 25 is a view, partially broken away and in cross section, of a first embodiment of a coupling and control assembly of the present invention;

[0080] FIG. 26 is a view similar to the view of FIG. 25 but with an actuator of the assembly moved away from the locking member;

[0081] FIG. 27 is a view similar to the views of FIGS. 25 and 26 but with the locking member in its down position;

[0082] FIG. 28 is a view similar to the view of FIG. 26 but including force arrows;

[0083] FIG. 29 is a view similar to the view of FIG. 27 but including force arrows;

[0084] FIG. 30 is a view, partially broken away and in cross section, of a second embodiment of a coupling and control assembly without any springs; and

[0085] FIG. 31 is a view similar to the view of FIG. 30 with the locking member in its laydown position in its pocket.

DETAILED DESCRIPTION

[0086] As required, detailed embodiments of the present invention are disclosed herein; however, it is to be understood that the disclosed embodiments are merely exemplary of the invention that may be embodied in various and alternative forms. The figures are not necessarily to scale; some features may be exaggerated or minimized to show details of particular components. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a representative basis for teaching one skilled in the art to variously employ the present invention.

[0087] In general, two different locking members or struts are disclosed herein which can be used in their respective coupling assemblies and coupling and control assemblies. The first locking member 102 is specifically shown in drawing FIGS. 11-15 and the second locking member 202 is specifically shown in drawing FIGS. 16-19.

[0088] A passive coupling assembly 100 including the first locking member 102 is shown in FIGS. 3 and 4 and a passive coupling assembly 200 including the second locking member 202 is shown in FIGS. 5, 6 and 20-23.

[0089] An active coupling and control assembly 100 using the first locking member 102 is shown in FIGS. 7 and 8 and an active coupling and control assembly 200 including the second locking member 202 is shown in FIGS. 9, 10 and 25-31.

[0090] Locking members or struts of the two embodiments have two functions or features. The first function is when there is an actively controlled strut with a dynamic clutch where the active strut is rotating with the pocket plate. The strut is actuated to move into the up position so that a lock could occur between the pocket plate and notch plate. When the actuation system is commanded so the strut can disengage itself, the centrifugal force generated by the rotating strut can hold itself into the pocket plate and prevent a disengagement from occurring due to friction. To overcome this issue, a return spring with more force can be used. In one embodiment of the invention, the strut can be disengaged with either a small return spring or no return spring depending on how the strut needs to behave at lower speeds. A strut similar to this can allow for a clutch design to exist that does not use any springs; e.g. a dynamic clutch that only needs to engage at speeds higher than, for example, 500 rpm.

[0091] The second function is for a non-controlled strut, also known as a passive strut. Certain one way clutches are designed so that the struts will laydown at a given speed (usually the lower the laydown speed the better). This speed is determined by pocket geometry, strut geometry, strut pitch diameter, spring force, and the frictional coefficient.

[0092] Another embodiment of the invention uses new geometry so that the struts will laydown at lower speeds, much lower than prior designs. Since the struts will laydown at low speeds, the oil supplied to the clutch can be lower. Currently oil is supplied to one way clutches to assist strut stability, help with strut laydown, and prevent rust and fretting. Using this embodiment, oils only purpose would be for rust and fretting prevention. Less oil in the system means lower drag and smaller pumps needed to pump the oil throughout the transmission.

[0093] The main difference in terms of calculations between these embodiments is the impact of friction. For an active strut, friction is detrimental and for a passive strut, friction is beneficial. This means that the pocket draft needs to be greater for an active strut than that of a passive strut. This is because an active strut is in the lock position and needs to return to the down position, but a passive strut gets pushed down into the pocket from the notch plate and need to stay down (so one needs to force the active strut into the pocket and keep the passive strut from coming out of the pocket). All other aspects of the embodiments between and active and passive strut can be the same.

[0094] In the first embodiment, the locking member or strut 102 (i.e. FIGS. 11-15) is a double drafted strut. The front side surfaces 120 of the strut 102 have a certain draft, and the back side surfaces 121 of the strut 102 have the inverse of the front draft. In this way the strut 102 can be used as either a forward or a reverse strut. These drafts are matched (are the inverse) with the pocket so that the strut side walls and the pocket side walls lineup to each other when the strut 102 is in the down (into pocket) position. The center of gravity does not need to be tightly controlled on this strut 102. The strut's laydown characteristics are dependent of the clutch diameter, clutch speed, strut mass, and draft angle and therefore can be altered to fit the application at hand.

[0095] In the second embodiment, the locking member or strut 202 (i.e. FIGS. 16-19) has large drafted ears 228 with side surfaces 220 that contact the pocket side walls. In like fashion, the strut 202 can be used as either a forward or a reverse strut. The draft on the strut ear side walls 220 is the inverse of the draft on the pocket ear (i.e. side walls) so that they line up together when the strut 202 is in the down position. This pocket and strut are easier to manufacture than the first embodiment. The center of gravity for this strut 202 needs to be in the ear portion of the pocket so that the strut 202 will not lose contact with the ear in the pocket plate 206. The strut's laydown characteristics are dependent of the clutch diameter, clutch speed, strut mass, and draft angle and therefore can be altered to fit the application at hand. The only trade off between the first and second embodiments is that the centrifugal force acting on the strut 202 of the second embodiment causes the strut 202 to want to push away the notch plate 210 more so than the first embodiment. To counteract this force an optional cover plate 208 (as shown in FIGS. 20-23) can be used to hold the strut 202 in the pocket. The cover plate 208 would look and act similar to a stationary selector plate.

[0096] The cover plate 208 prevents the strut 202 from pushing on the notch plate 210 when the strut 202 is laying down. The strut 202 allows for strut laydown to occur at a low RPM and with lower variance than the prior art (i.e. see graphs of FIG. 24). Typically, the lower the laydown speed the better for the passive strut 202. However, when a passive strut needs to engage in a dynamic situation (where both plates 206 and 210 are rotating) the strut 202 is beneficial.

[0097] FIGS. 22 and 23 are similar to FIGS. 20 and 21, respectively, but include different arrows which represent forces. Arrow 300 is a frictional force, arrow 302 is a sliding force from centrifugal forces (contact moves up to this point when the strut 202 pitches up), arrow 304 is the cover plate force and arrow 306 is the spring force. In FIG. 23, arrow 308 is a frictional force, arrow 310 is a cover plate force and arrow 312 is the sliding force from centrifugal forces and arrow 314 is the spring force.

[0098] As shown in FIGS. 25-29, a controlled or active rotating strut 202 is actuated to move into the up position so that a lock can occur between the pocket plate 206 and notch plate 210. When an actuation system including plate 204 and springs 215 is commanded so the strut 202 can disengage itself, the centrifugal force generated by the rotating strut 202 can hold itself in the pocket plate 206 and prevent a disengagement from occurring due to friction. To overcome this issue, a return spring 214 with more force can be used. With at least one embodiment of the invention, the strut 214 can be disengaged with either a small return spring, or no return spring depending on how the strut 202 needs to behave at lower speeds.

[0099] A strut similar to this can allow for a clutch design to exist that does not use any springs (i.e. as shown in FIGS. 30 and 31); e.g. a dynamic clutch that only needs to engage at speeds higher than 500 rpm. This feature can be achieved with a strut 202 (i.e. FIGS. 30 and 31) that is opposite the strut 202 (i.e. the center of mass and main contact is at the body and not the rear). The embodiment of FIGS. 30 and 31 is similar to the embodiment of FIGS. 25-27. Consequently, the parts of the embodiment of FIGS. 30 and 31 have the same reference number but a double prime designation.

[0100] FIGS. 28 and 29 are similar to FIGS. 26 and 27, respectively, but include arrows which represent forces. Arrow 300 is a frictional force, arrow 302 is a sliding force from centrifugal forces, arrow 304 is a spring force and arrow 306 is a cover plate force. In FIG. 29, arrow 308 is a spring force, arrow 310 is a frictional force, arrow 312 is a cover plate force and arrow 314 is a sliding force from centrifugal forces.

[0101] All one-way clutches have members that hold the load between two other members. Sprag clutches have sprags, roller clutches have cylindrical rollers, and mechanical diodes have struts. The durability during overrun of these clutch styles are usually limited by the sprag, roller, or strut members since they contact members that are rotating.

[0102] At least one embodiment of the invention allows for struts to laydown and get out of the way of rotating members at a fraction of the speeds previously design at. As an example, old methods have gotten the struts to laydown in a certain prior art one-way clutch around 1,800 rpm with large variation. At least one embodiment of the invention allows the strut in the same application to laydown around 400 rpm with little variation. With the traditional strut/pocket plate design, differences in the frictional coefficient causes large differences in the laydown speeds, and as shown in the graphs of FIG. 24 differences in the frictional coefficient causes little differences in laydown speed. This means that a clutch using locking members of at least one embodiment of the invention should see strut laydown speeds to be very similar when using less or no oil, much different than traditional designs.

[0103] FIGS. 3 and 4 show a passive coupling assembly, generally indicated at 100, which includes a plurality of the locking members or struts, generally indicated at 102 in FIGS. 11-15. The assembly 100 includes a backing phase, generally indicated at 104, a pocket plate, generally indicated at 106, an optional cover plate, generally indicated at 108, a notch plate, generally indicated at 110, and a snap ring, generally indicated at 112, which holds all of the plates 104, 106, 108 and 110 together. Biasing members or springs 114 bias their respective struts 102 within their respective pockets.

[0104] In like fashion, FIGS. 5 and 6 show a passive coupling assembly, generally indicated at 200, which include the locking member or strut, generally indicated at 202, of FIGS. 16-19. The assembly 200 include a backing plate 204, a pocket plate 206, an optional cover plate 208, a notch plate 210 and a snap ring 212 which holds all the plates 204, 206, 208 and 210 together. Biasing members or springs 214 bias their respective struts 202 within their respective pockets. In general, a cover plate such as the cover plates 108, 208, 208 and 208 allows for a more robust and lower drag clutch but such a cover plate is optional.

[0105] FIGS. 7 and 8 show an active coupling and control assembly, generally indicated at 100. The parts of the active assembly 100 which are the same or similar in either structure or function to the parts of the passive assembly 100 have the same reference number but a single prime designation. The assembly 100 further includes actuating biasing members or springs 115 mounted on the moveable backing plate 104 to actuate the respective struts 102 as best shown in FIGS. 25-29.

[0106] FIGS. 9 and 10 show an active coupling and control assembly, generally indicated at 200. The parts of the active assembly 200 which are the same or similar in either structure or function to the parts of the passive assembly 200 have the same reference number but a single prime designation. The assembly 200 further includes actuating biasing members or springs 215 mounted on the moveable backing plate 204 to actuate their respective struts 202.

[0107] Referring again to FIGS. 11-15, the strut 102 has front and rear side surfaces 120 and 121, respectively, one pair of which slidably contacts a pocket side surface during locking member laydown. The strut 102 also includes a member-engaging first end surface 122, a member-engaging second end surface 124 and an elongated main body portion 126 between the end surfaces 122 and 124. At least one and preferably two (so that the strut can be used either as a forward or a reverse strut) projecting pivots or ears 128 extends laterally from the main body portion 126 for enabling pivotal motion of the locking member 102 during locking member laydown. The end surfaces 122 and 124 of the locking member 102 are moveable between engaged and disengaged positions with respect to the coupling members 106 and 110 during the pivotal motion whereby one-way torque transfer may occur between the coupling members 106 and 110. The side surfaces 120 and 121 have a draft with a draft angle to improve locking member dynamics with regards to locking member laydown speed and to minimize laydown speed variation caused by a variable frictional coefficient between the pocket side surfaces and the side surfaces 120 and 121 of the strut 102 as shown by the graphs of FIG. 24.

[0108] When used as a passive locking member or strut, the strut 102 has a draft angle which lies in a range of 0.0 to 30.0 and when used as an active locking member or strut, the strut 102 has a draft angle which lies in a range of 5 to 30. The drafts of the front and rear side surface, 120 and 121, respectively, are preferably the inverse of one another.

[0109] Referring to FIGS. 16-19, the strut 202 has two side surfaces 220 (so that the strut can be used as either a forward or a reverse strut) one of which slidably contacts the pocket side surface during locking member laydown. The strut 202 also includes a member-engaging first end surface 222, a member-engaging second end surface 224 and an elongated main body portion 226 between the end surfaces 222 and 224. A pair of projecting pivots 228 extends laterally from the main body portion 226 for enabling pivotal motion of the locking member 202 during locking member laydown. The end surfaces 222 and 224 of the locking member 202 are moveable between engaged and disengaged positions with respect to the coupling members 206 and 210 during the pivotal motion whereby one-way torque transfer may occur between the coupling members 206 and 210. Each of the side surfaces 220 has a draft with a draft angle to improve locking member dynamics with regards to locking member laydown speed and to minimize laydown speed variation caused by a variable frictional coefficient between the pocket side surface and the side surface 220. As in the case of locking member 102, when used as a passive locking member the strut 202 has a draft angle which lies in a range of 0.0 to 30.0 and when used as an active strut, the strut 202 has a draft angle which lies in a range of 5 to 30.

[0110] Each of the pockets in the pocket plates 106, 206, 106 and 206 provides sufficient clearance to allow sliding movement of its locking member during movement of the locking member between engaged and disengaged positions. Each locking member may be an injection molded locking member such as a metal injection molded locking member or part.

[0111] In the embodiments of FIGS. 7-10, the first coupling member or pocket plate also has a face having a plurality of passages spaced about the rotational axis of the assembly and including passages in communication with the pockets. The passages communicate actuating forces (typically via actuating springs) to their respective locking members within their respective pockets. The face and the opposite face are generally annular and extend generally radially with respect to the rotational axis of the assembly. Actuators, such as spring actuators, may be received within the passages to provide the actuating forces to actuate the locking members within their respective pockets so that the locking members move between their engaged and disengaged positions. Other types of actuators besides the spring actuators may be used to provide the actuating forces. Also, pressurized fluid may be used to provide the actuating forces. Biasing members such as coiled return springs bias the locking members against pivotal motion of the locking members towards their engaged positions. The spring actuators pivot their locking members against the bias of the spring biasing members. Each pocket has an inner recess for receiving its respective biasing spring wherein each pocket is a spring pocket.

[0112] While exemplary embodiments are described above, it is not intended that these embodiments describe all possible forms of the invention. Rather, the words used in the specification are words of description rather than limitation, and it is understood that various changes may be made without departing from the spirit and scope of the invention. Additionally, the features of various implementing embodiments may be combined to form further embodiments of the invention.