GB2200191A

GB2200191A - Piloted hub for a clutch driven disc assembly

Info

Publication number: GB2200191A
Application number: GB08726998A
Authority: GB
Inventors: Michael L Bassett
Original assignee: Dana Inc
Current assignee: Dana Inc
Priority date: 1986-11-28
Filing date: 1987-11-18
Publication date: 1988-07-27
Anticipated expiration: 2007-11-18
Also published as: GB8726998D0; JP2652857B2; DE3737787A1; BR8706189A; FR2607565A1; JPS63140124A; GB2200191B

Description

0, Z1 L 4 1 TITLE IMPROVED PILOTED HUB FOR A CLUTCH DRIVEN DISC ASSEMBLY

2200 191

BACKGROUND OF THE INVENTION

The present invention relates in general to rotary torque transmitting devices and-in particular to an improved.piloted hub structure for use in a clutch driven disc assembly.

In most passenger cars and trucks, objectionable vibrations may be generated in the vehicle drive line at certain speeds and load conditions. Some of these disturbances may be eliminated, or reduced to an acceptable level, by incorporating a torsional damper in a driven disc assembly of the vehicle clutch. Typicallyi such dampers include a- plurality of circumferentially spaced coiled__ springs operatively connected between two relatively_ rotatable elements of the clutch driven disc assembly.

Clutches having dampers similar to that described above are widely used in vehicular rotary torque transmitting systems. Usually, the two elements of the clutch driven disc assembly are permitted to rotate. relative to each other by a relatively.small amplitude, approximately ten degrees total angular displacement or less. In such situations, conventional dampers have been found to operate sufficiently well. In certain applications, however, it has been found to be desirable to permit the two relatively rotatable elements to rotate relative to each other by a relatively large amplitude, up to approximately twenty degrees total angular displacement or more. In either case, it is important that two relatively rotatable elements be precisely positioned relative to each other such that they rotate about a common axis. Failure to so align the axes of rotation of the two C1 2 rotatable elements can cause premature wear of the disc assembly and other undesirable effects.

SUMMARY OF THE INVENTION

The present invention relates to an improved piloted hub structure for a clutch driven disc assembly. The assembly includes a pair of spaced outer covers connected to a central hub. The hub is generally cylindrical in shape, but is provided with an integral annular flange extending radially outwardly at or near the longitudinal center thereof. Two tabs are f6rmed integrally with the hub flange and extend in opposite directions. The two oppositely extending tabsdefine a major axis through the hub. The opposed arcuate portions of the hub flange which extend between the tabs define a minor axis through the hub. A support plate is provided with a central aperture which is shaped having opposed slots, permitting it to be disposed about the hub flange and the hub tabs between the two outer covers. The support plate is rotatable relative to the hub and the outer covers to a limited extent. The support plate central aperture is shaped to pilot the hub therein in two directions. Major axis inner surfaces of the support plate central aperture engage corresponding major axis outer surfaces formed on the exteriors of the hub tabs to pilot the hub in a first direction, while minor axis inner surfaces of the support plate central aperture engage corresponding minor axis outer surfaces formed on the exteriors of the hub between the tabs to pilot the hub in a second direction. Preferably, the major and minor axes are oriented at a right angle relative to one another.

It is an object of the present invention to provide an improved spring damper drive for a clutch driven disc assembly.

It is another object of the present invention to provide such a spring damper drive which pilots'the_first rotary torque transmitting element within the second rotary i 1 CD 1 1 3 torque transmitting element along major and minor axes so as to maintain relative co-axial rotation.

Other objects and advantages of the present invention will become app arent to those skilled in the art from the following detailed description of the preferred embodiment, when read in light of the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

Fig. 1 is anend elevational view, partially broken awayr of a clutch driven disc assembly in accordance with the present- invention, the support plate being shown in a neutral position relative to the hub.

Fig. 2 is an enlarged sectional elevational view taken along line 2-2 of Fig. 1.

15. Fig. 3 is an enlarged fragmentary view of a portion of the clutch driven disc assembly illustrated in Fig. 1, the support plate being shown in an engaged position relative to the hub.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring now to the drawings, there is illustrated a rotary torque transmitting device, indicated generally at 10, including an improved piloted hub structure in accordance with the present invention. Typically, the rotary torque transmitting device 10 constitutes a driven disc assembly of a clutch (not shown). The clutch is normally positioned in a vehicle drive train between an engine and a transmission. In general, the disc assembly 10 includes two rotary torque transmitting elements which are rotatable relative to one another throughout a limited angular distance. The rotary torque transmitting elements are connected together by a lost motion connection and by a spring damper drive. The lost motion connection is utilized to establish a positive-driving connection between the two rotary torque transmitting elements, while permitting a limited range of free movement therebetween.

1 Cl, 4 The spring damper drive is utilized to establish a resilient driving connection between the two rotary torque transmitting elements within the limited range of free movement permitted by the lost motion connection. The spring damper drive-can also be utilized to tune the vehicle drive train so as to prevent vibrations from occurring within the operating speed range of the engine.

In the preferred embodiment of the invention, the first rotary torque transmitting element of the disc assembly 10 is formed from a generally cylindrical hub 12 and a pair of spaced apart outer covers 14. The hub 12 is generally hollow and cylindrical in shape, but has an integral radially outwardly-extending flange 16 formed at or near the longitudinal center thereof. The outer covers 14 have respective central apertures 14a formed therein which permit the outer covers 14 to be disposed about the hub 12 on either side of the hub flange 16. A pair of secondary covers 18 are also provided in the disc assembly 10. The secondary covers have respective central apertures 18a formed therein which permit the secondary covers 18 to be disposed about the hub 12 between each of the outer covers 14 and the hub flange 16. The outer covers 14 and the secondary covers 18 are all secured to the hub flange 16 by a plurality of rivets 19 spaced about the circumference of the hub 12. The rivets 19 extend through respective apertures formed through the outer covers 14, the secondary covers 18, and the hub flange 16 to form a unitary structure for the first rotary torque transmitting element.

The second rotary torque transmitting element of the disc assembly 10 is formed from a support plate 20. The support plate 20 includes a central aperture, indicated generally at 20a, which permits the support plate 20 to be disposed about the hub flange 16 between the secondary covers 18. The support plate 20 has a plurality of friction pads 21 secured to the opposed sides thereof. Two i i 1 1 C, of the friction pads 21 are secured to the opposite sides of the radially outermost portions of each of a plurality of radially extending arms 22 formed integrally with the support plate 20. As best illustrated in Fig. 2, a pair of reinforcing plates 23 are provided, each having respective central apertures 23A formed therein. The reinforcing_ plates 23 are disposed about the hub flange 16 between the support plate 20 and one of the secondary covers 18. The reinforcing plates 23 are securely fastened to the support plate 20 by a plurality of rivets 24. The rivets 24 extend through respective apertures formed through the reinforcing plates 23 and the support plate 20 to form a unitary structure for the second rotary torque transmitting element.

15.. As is well known, the hub 12 may be splined onto an input shaft (not shown) of the vehicle transmission such that the frictionpads 21 attached to the support plate 20 are disposed between an axially movable clutch pressure plate and an axially -stationary engine driven. flywheel (neither shown). Thus, the disc assembly 10 rotates with the transmission- input s-haft and is permitted to move axially along such shaft throughout a limited distance.

The outer covers 14 and the secondary covers 18 are each formed with respective pluralities of spring openings, indicated generally at 25 and 26. Similarly, the support plate 20 and the reinforcing plates 23 are each provided with respective pluralities of spring openings 27 and 28. The spring openings 25, 26, 27, and 28 are aligned with each other, as illustrated in Fig. 1, and may be formed in an evenly spaced circular array about the disc assembly 10. Additional spring openings, indicated generally at 29, may.be provided within the circular array if desired. The spring opening-s 25, 26, 27, and 28 are all shaped generally in the shape of a truncated sector. Referring specifically to the outer cover 14, the outer cover spring opening 25 is formed having having a linear inner wall 25a oriented 6 perpendicularly to a bisecting radius of the outer cover 14, a pair of end walls 25b extending perpendicularly outwardly from each end of the linear inner wall 25a, and an arcuate outer wall 25c connecting the two end walls 25b.

In accordance with the teachings of United States Patent No. 4,254,855 to Hildebrand et al., the spring openings 25, 261 27, and 28 are adapted to receive and retain a first plurality of coil springs 30 therein. The disclosure of that patent is hereby incorporated by reference. A second plurality of coil springs 32 may be provided having smaller outer diameters than the inner diameters of the first plurality of coil springs 30. Each of the second plurality of coil springs 32 can be disposed within a respective one of the first plurality of coil springs 30 so as to be retained within the spring openings 25, 26, 27, and 28. Each of the first and second pluralities of coil ' springs 30 and 32 extends throughout the spring openings 25, 26, 27, and 28 and has its longitudinal axis oriented transversely relative to the radius of the disc assembly 10. Although the present invention is disclosed as having the first and second pluralities of coil springs 30 and 32, it should be understood that the use of the second plurality of coil springs 32 is optional in the present invention.

As best shown in Figs. 1 and 3, the hub flange 16 is formed having two integral tabs 40 which extend radially outwardly therefrom in opposite directions. Each of the tabs 40 is defined by a pair of side walls.41 which terminate at an arcuate puter wall 42. The opposed tab outer walls 42 define a major axis through the hub 12 which extends in a direction which is generally perpendicular to the upper portion of the line 2-2 illustrated in Fig. 1.

Between the two tabs 40, the hub flange 16 is generally circular in shape, having opposed arcuate outer surfaces 46. The opposed arcuate surfaces 46 of the hub flange 16 define a minor axis through the hub 12 which extends'in a 1 G f Q -r 7 direction which is generally parallel to the upper portion of the line 2- 2 illustrated in Fig. 1 and,, therefore-, which is generally perpendicular to the major axis described above. The tab outer walls 42 and the outer arcuate -- surfaces 46 of the hub flange 16 are utilized to pilot the hub 12 within the disc assembly 10 for co-axial rotation with the support plate 20, as described in detail below.

The tab outer walls 42 and the outer arcuate surfaces 46 are each engaged by the central aperture 20a formed in the support plate 20 to achieve this.piloting action. As best illustrated in Fig. 1, the central aperture 20a of the support plate 20 is formed having a pair of opposed inner arcuate walls 48 separated by opposed slots formed in-the support plate 20. Each of the slots is defined by a pair of flats 50 which extend outwardly from respective ends of the inner arcuate walls 48 and which terminate in an arcuate end wall 51. Each slot surrounds a respective one of the tabs 40 formed on the hub flange 16. Each flat 50 of each slot is normallyspaced apart from the corre sponding side wall 41 of each of the tabs 40, asillustrated in Fig. 1, because the coil springs 30 and 32 urge the support plate 20 to that position relative to the hub 12 when the clutch is disengaged. The arcuate end walls 51, however, of the slots engage the corresponding outer walls 42 of the tabs 40 continuously. Such engagement pilots the hub 12 along its major axis described above. Similarly, the opposed arcuate inner walls 48 of the support plate central aperture 20a continuously engage the outer arcuate surfaces 46 formed on the hub flange 16 between the tabs 40.. As a result, the hub 12 is piloted along its minor axis as well. Thus, the hub 12 is reliably positioned relative to the support plate 20 for relative rotation about a common axis. The illustrated structure permits the hub 12 to be rotated by a relatively large amplitude of angular displacement relative to the support plate 20 while maintaining such co-axial alignmen t. To 1 i c 8 accommodate the limited rotation that occurs between the hub 12 and the support plate 20, a plurality of openings 52 are provided in the outer covers 14 and the secondary covers 18. The openings 52 provide the necessary clearance for the rivets 24 during relative rotation between the hub 12 and the support plate 20.

In Fig. 11 the support plate 20 is illustrated in a neutral angular position relative to the hub 12. When the clutch is engaged, the support plate 20 can be rotated a predetermined maximum.amount, approximately ten degrees relative to the hub 12 in either direction from the neutral position, from the position illustrated in Fig. 1 before the flats 50 of the central apertures 20a engage the corresponding side walls 41 of the tabs 40, as shown in Fig. 3. The abutment of the flats 50 against the side walls 41 of the tabs 40 establishes a direct drive connection between the hub 12 and the support plate 20. Such abutment will occur only when the first and second rotary torque transmitting elements are rotated -relative to one another by this Paximum amount against the urging of. the first and second pluralities of coil springs 30 and 32. Thus, a resilient-driving connection is normally provided between the support plate 20 and the hub 12. This resilient driving connection is sufficient to absorb vibrations and oscillations which might be generated because of the relatively large amplitude of angular displacement permitted by the disc assembly 10. The resilient driving connection will be maintained so long as the two rotary torque transmitting elements are rotated, relative to the other, by less than the predetermined amount. If rotation by more than the predetermined maximum amount is attempted, the side walls 41 of the tabs 40 will abut the flats 50, thereby establishing a positive driving connection as illustrated in Fig. 3.

In accordance with the provisions of the patent statutes, the principle and mode of operation of the C 9 AI present invention have been explained and illustrated in its preferred embodiment. However, it must be understood that the present invention may be practices otherwise than as specifically explained and illustrated without departing from its spirit or scope.

1V is

Claims

What is claimed is: 1. A torque transmitting device comprising: a

rotatable hub member having a longitudinal passageway with a longitudinaxis formed therethrough, said hub member being adapted to receive a shaft with a longitudinal axis in said longitudinal passageway for rotation therewith, said hub member being formed generally with an outside surface that has a major axis portion and.a minor axis portion, the axis of said major axis portion and the axis of said minor axis portion extending perpendicularly with respect to one another and with respect to said longitudinal axis of said hub member; and at least one annular disc having a central aperture formed therein, said inside surface of said annular disc engaging said hub member so as to permit limited relative rotational movement between said -annular disc and said hub member while maintaining said longitudinal axis of said longitudinal passageway of said hub member co- axial with the longitudinal axis of the shaft.
2. A torque transmitting device according to Claim 1 wherein said inside surface of said annular disc has a major axis portion and a minor axis portion, said major axis portion of said inside surface of said annular disc engaging said major axis portion of said outside surface of said hub member and said minor axis portion of said inside surface of said annular disc engaging said minor axis portion of said outside surface of said hub member.
3. A torque transmitting device substantially as described herein with reference to, and as shown in, the accompanying drawings.

Published 191RSatrhe Patent Office, State House. 66"71 High Holborn, London WCIR 4TP, Further copies maybe obtained from The Patent Office, Sales Branch, St Mary Cray, Orpington, Kent BR5 3RD. Printed by Multiplex techniques Itd. St Mar7 Cray, Kent. Con. 1/87.