WO2009020564A1

WO2009020564A1 - Hydraulic segmented synchronizer to engage and disengage gear selection for dct

Info

Publication number: WO2009020564A1
Application number: PCT/US2008/009323
Authority: WO
Inventors: Thomas E. Braford, Jr.
Original assignee: Borgwarner Inc.
Priority date: 2007-08-07
Filing date: 2008-08-01
Publication date: 2009-02-12
Also published as: WO2009020564A9

Abstract

A fluid actuated clutch is provided for connecting a coaxially mounted gear on a rotating shaft. The clutch arrangement includes a post mounted on the shaft providing a fluid boundary. The post has a fluid delivery passage in fluid communication with a passage in the shaft. An applied piston is provided which is slideably mounted on the shaft and which forms a sealed control volume with the post. The control volume is exposed to the post fluid delivery passage. The apply piston has a conical engagement surface. A circumferentially segmented cone is also provided. The cone has a first engagement surface for engagement with the apply piston conical engagement surface. The post has a second engagement surface for engagement with the gear.

Description

HYDRAULIC SEGMENTED SYNCHRONIZER TO ENGAGE AND DISENGAGE GEAR SELECTION FOR DCT

CROSS-REFERENCE TO RELATED APPLICATIONS This application is a PCT International Application of United States

Patent Application No. 60/963,705 filed on August 7, 2007.

TECHNICAL FIELD

The present invention relates to clutches for engaging a co-axially mounted gear on a rotating shaft. The present invention is particularly useful in dual clutch transmissions.

BACKGROUND OF THE INVENTION

Currently for gear selection, most dual clutch transmissions utilize a system with actuator valves with linear position sensors, rails and forks and synchronizers to achieve gear selection of a given selected co-axially mounted gear on a rotating shaft. It. is desirable to provide a gear selection which eliminates need for actuator valves, linear position sensors, rails, forks and the typical standard configuration of the synchronizer that includes expensive spline features. To achieve the above noted desire, the present invention is brought forth which makes manifest a clutch for connecting a gear with a rotating shaft which utilizes dual conical clutch action.

SUMMARY OF THE INVENTION

An arrangement for a synchronizer, a clutch with synchronizing capabilities for selecting a gear on a rotating shaft is provided. The clutch includes a post mounted shaft providing a fluid boundary, the post having a fluid delivery passage in fluid communication with a passage in the shaft. An apply piston is provided slideably forming a sealed control volume with the post wherein the control volume is exposed to the post fluid delivery passage, the apply piston having a conical engagement surface. A circumferentially segmented cone is provided. The cone has a first engagement surface for engagement with the apply piston conical engagement surface and a second engagement surface for engagement with the gear.

BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1 is a sectional view of a preferred embodiment clutch arrangement according to the present invention;

Figure 2 is a sectional view taken along a different angle from that shown in Figure 1 ;

Figure 3 is still another sectional view taken from a different angle from that of Figures 1 and 2;

Figure 4 is an exploded view of the clutch shown in Figures 1 , 2 and 3;

Figure 5 is a sectional view similar to that of Figure 1 of an alternate preferred embodiment clutch arrangement according to the present invention.

Figure 6 is a sectional view of another alternate preferred embodiment of the present invention;

Figure 7 is a partial sectioned perspective view of the clutch shown in Figure 6 with portions removed for clarity of illustration; Figure 8A is a perspective view of a cone segment of the clutch of

Figures 6 and 7;

Figure 8B is a front view of a cone segment of the clutch of Figures 6 and 7;

Figure 8C is a top view of a cone segment of the clutch of Figures 6 and 7;

Figure 8D is a rear view of a cone segment of the clutch of Figures 6 and 7;

Figure 9 is a perspective view of a cone segment of the clutch of Figures 6 and 7; DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The following description of the preferred embodiment(s) is merely exemplary in nature and is in no way intended to limit the invention, its application, or uses. Referring to Figures 1-4, a fluid or hydraulic actuated clutch arrangement 7 of the current invention has a rotational shaft 10 with rotates about axis 12. The shaft has rotatably therein a first co-axially mounted gear 14 and a second co-axially mounted gear 16. The shaft 10 and gears 14 and 16 are typically part of a vehicle transmission particularly a dual clutch transmission identical or similar to those described in U.S. Patents 6,715,597, 6,832,978, 6,953,417 and 7,155,993. The gears 14 and 16 are rotatably mounted upon the shaft 10 by needle bearings (not shown). Accordingly, in most instances, the gears 14 and 16 freely rotate upon the shaft 10. Splined to the shaft 10 is a post 18. The post 18 has a lower body 20. Extending radially outward from the lower body 20 is a series of circumferentially spaced tabs 22. Above the tabs 22 is an upper rim 24. The upper rim 24 has a sealing groove 26. Seated within the sealing groove 26 is an annular sealing member 28. Above the rim 24 there is a post extension 30. From the post extension 30, the post extends outward into a top T member 32. Between the sealing member 26 and the extension 30 is a supply passage 34. The supply passage 34 intersects with a radial extension 36 and an axial passage 38 provided in the shaft 10. The post 18 provides a fluid boundary. Slidably mounted on the post 10 between the T 32 and the rim 24 is an apply piston 40. The apply piston is sealed by the sealing member 28 and also has its own sealing groove 42 which mounts an annular sealing member 44. The sealing piston 40 is biased to a non-actuated position by a plate spring 46 that is held in position by a snap ring 48. The sealing members 28 and 44 cooperate to form between the apply piston 40 and the post 18 a control volume 49 which is exposed to the passage 34. The arrangement 7 also has a cone 50. The cone 50 is preferably segmented into 3 or more geometrically divided segments (as shown 4). The cone is "C" shaped in an axial cross-section having a first engagement surface 52 and a second engagement surface 54 on its opposite sides. The first engagement surface 52 has non-self locking engagement with engagement surface 58 of the piston. Both engagement surfaces 52 and 58 are non-parallel with the axis 12 of the shaft. The angle of engagement of the first engagement surface 52 and the piston engagement surface is non-self engaging typically in a general range of 6° to 8°. The engagement surfaces 52 are formed on circumferentially spaced tabs 60 of the cone. The tabs 60 are circumferentially intermixed with tabs 22 of the post for torsional transference there between.

The second engagement surface 54 can be provided by a friction lining connected with the cone 50. The second engagement surface 52 has self-locking engagement with an engagement surface 62 of the gear 14. Typically, the engagement surfaces 52 and 62 will both be non-parallel with the shaft rotational axis 12. The cone 50 engagement with the gear 14 is in the range of a 2° to 3° engagement angle. The cone 50 can be easily released from engagement with the gear 14 since it is segmented.

To pressurize the clutch 7 for the shaft 10 to engage the gear 14, pressurized hydraulic fluid from the transmission is delivered to a radial fluid line 70 that passes between annular sealing members 72. The fluid line 70 connects with the axial path 38. From axial path 38, the pressurized fluid enters the generally radial extension 36 into the supply passage 34 wherein it pressurizes a control volume that is bordered by the apply piston 40 and the post 18. The apply piston 40 is slid outwardly causing its engagement surface 58 to engage the cone engagement surface 52. The above noted action will be great enough to overcome the biasing of plate spring 46 and thereafter the cone 50 will be forced radially outward from the post 18 causing its second engagement surface 54 to engage with the gear engagement surface 62. When the hydraulic fluid is switched to a drain by a valve (not shown), the spring 46 will cause the piston 40 to be retracted to its non-actuated position and the cone 50, due to its segments, will release its second engagement surface 54 from the gear engagement surface 62. To connect the gear 16 with the shaft 10, fluid is delivered into the axial passage 74 wherein it is delivered into a radial passage 76 and into supply passage 78 to actuate the piston 40 associated with the gear 16. The remainder of the operation in regards to engaging gear 16 is identical to that previously explained. Accordingly, the post 18 supplies a pressure border for both of the clutch arrangements.

Referring to Figure 5, in an embodiment 117 of the present invention illustrates a fluid or hydraulically actuated clutch arrangement wherein the cones second engagement surface 154 is radially outward from the cone 150 first engagement surface 152. The gear 114 has an extension 115 to provide the engagement surface for the gear. In a similar manner, the gear 116 has an extension 119 to provide on its inner radial side an engagement surface. The clutch 117 works in a manner generally similar to that described having a piston 140 which is bias to a retracted position by a spring 146. Pressurization of a control volume between the piston 140 and the post 118 causes the engagement surface of the piston 158 to engage the first engagement surface 152 of the cone 150 in a non-self locking fashion. Further movement of the piston 80 outward causes the cone 150 to be displaced axially to the left as shown in Figure 5 causing it to engage with the engagement surface 162 of the gear 114 in a self-locking manner. The cone 150 is segmented preferably into three or more segments.

Referring to Figures 6-9, a clutch arrangement 217 is provided which in function is similar or almost identical to that previously described for clutch arrangement 117. Clutch 217 has gears 216 and 214. Clutch arrangement 217 has a post 218 and apply piston 240. The post 218 has T members 232 having a central slot or groove 219. The top of the T members have a circumferential groove 223. Fixably pressed onto the grooves 223 are two annular rod members 225. The rod members 225 provide a pivotal fulcrum for the cone segments 250. The cone segments 250 have tabs 259 which are intermixed between the post's T members 232. The cones 250 have on their tab members 259 a circumferential groove 263 that is fitted underneath the rods 225. Inserted within the groove 219 of the post T members 232 is a radially outwardly expanding spring 221 which engages with a radial underside 267 of the cone's tab to directly bias the cones to pivot against the rods 225 to prevent drag and inadvertent engagement of the cone second friction surface 254 with the gear friction surfaces provided by the underside of extensions 219 or 215 of the gears.

Those skilled in the art can now appreciate from the foregoing description that the broad teachings of the present invention can be implemented in a variety of forms. Therefore, while this invention has been described in connection with particular examples thereof, the true scope of the invention should not be so limited, since other modifications will become apparent to the skilled practitioner upon a study of the drawings, specification and following claims. The description of the invention is merely exemplary in nature and, thus, variations that do not depart from the gist of the invention are intended to be within the scope of the invention. Such variations are not to be regarded as a departure from the spirit and scope of the invention.

Claims

CLAIMS What is claimed is:

1. A fluid actuated clutch arrangement for connecting a coaxially mounted gear with a rotating shaft: a post mounted on said shaft providing a fluid boundary, said post having a fluid delivery passage in fluid communication with a passage in said shaft; an apply piston slideably forming a sealed control volume with said post wherein said control volume is exposed to said post fluid delivery passage, said apply piston having a conical engagement surface; and a circumferentially segmented cone, said cone having a first engagement surface for engagement with said apply piston conical engagement surface and a second engagement surface for engagement with said gear.

2. A clutch arrangement as described in claim 1 wherein an angle of engagement for said cone to said gear is self locking in a range approximately 2 to 3 degrees.

3. A clutch arrangement as described in claim 1 wherein an angle of engagement of said cone first engagement surface and said piston is non self locking wherein said angle of engagement is approximately between 6 to 8 degrees.

4. A clutch arrangement as described in claim 1 wherein at least one of said engagement surfaces on said cone and said piston is non parallel with an axis of said shaft.

5. A clutch arrangement as described in claim 1 wherein one of said engagement surfaces for said cone and said gear is non parallel with an axis of said shaft.

6. A clutch arrangement as described in claim 1 wherein said piston is spring loaded to a non actuated position.

7. A clutch arrangement as described claim 1 wherein said cone has tabs circumferentially intermixed with tabs of said post.

8. A clutch arrangement as described in claim 7 wherein said cone is generally "C" shaped having engagement surfaces on generally opposite sides of said "C".

9. A clutch arrangement as described in claim 1 wherein said cone first engagement surface is radially outward from said cone second engagement surface.

10. A clutch arrangement as described in claim 1 wherein said cone first engagement surface is radially inward from said cone second engagement surface.

11. A clutch arrangement as described in claim 10 wherein said cone is directly biased from engagement with said gear.

12. A clutch arrangement as described in claim 1 further including a second clutch arrangement for a second gear substantially similar to said first clutch arrangement, said second clutch arrangement having a common post with the first clutch arrangement.

19. A hydraulic actuated clutch arrangement for connecting a coaxially mounted gear with a rotating shaft, said gear having a cone engagement surface, said clutch arrangement comprising: a post mounted on said shaft providing a fluid boundary, said post having a fluid delivery passage in fluid communication with a passage in said shaft; an apply piston slideably forming a sealed control volume with said post wherein said control volume is exposed to said post fluid delivery passage, said applied piston having a cone engagement surface, said apply piston being biased to a non-actuated position; and a circumferentially segmented cone, said cone having a first engagement surface for non-self locking engagement with said piston and a second engagement surface for self locking engagement with said gear.

14. A clutch arrangement as described in claim 13 wherein said cone first engagement surface is radially outward from said cone second engagement surface.

15. A hydraulic actuated clutch arrangement for connecting a coaxially mounted gear with a rotating shaft, said gear having a cone engagement surface, said clutch arrangement comprising: a post mounted on said shaft providing a fluid boundary, said post having a fluid delivery passage in fluid communication with a passage in said shaft, said post having circumferentially spaced series of tabs; an apply piston slideably forming a sealed control volume with said post wherein said control volume is exposed to said post fluid delivery passage, said applied piston having a cone engagement surface, said apply piston being spring biased to a non-actuated position; and a cone having at least 3 circumferential segments, said cone being generally C shaped having on opposite sides a first engagement surface for non-self locking engagement with said piston and a second engagement surface for self locking engagement with said gear, said cone having a portion circumferentially intermixed with said tabs of said post.