GB2085552A

GB2085552A - Damper Disc

Info

Publication number: GB2085552A
Application number: GB8128522A
Authority: GB
Original assignee: Daikin Manufacturing Co Ltd
Current assignee: Exedy Corp
Priority date: 1980-09-30
Filing date: 1981-09-21
Publication date: 1982-04-28
Also published as: AU7591481A; JPS6014213B2; DE3138943C2; GB2085552B; ZA816596B; DE8128631U1; AU528126B2; JPS5761827A; DE3138943A1

Abstract

A damper disc applicable to a clutch disc comprises a hub flange 3; a pair of annular side plates 5, 6; a pair of annular sub-plates 16 disposed respectively between the side plates 5, 6 and the flange 3; stud pins 18 connecting the sub-plates 16 together; recesses 33 formed at middle portions of the side edges of openings 24, 25, 23 in the flange 3, each stud pin 18 extending through said each recess 33 with a spacing corresponding to a torsion angle for first hysteresis torque between the stud pin 18 and the side edge of the recess 33; stop pins 12 connecting the radially outer portions of the side plates 5, 6 together; notches 30 are formed at outer edges of the openings 24, 25, 23 in the flange 3, each stop pin 12 extending through each notch 30 with a space corresponding to a maximum torsion angle between the stop pin 12 and the side edge of the notch 30. Friction damping 15, 17 of differing degree is applied to sub plates and side plates. Three differing sizes 20, 21, 22 of torsion spring are used. <IMAGE>

Description

SPECIFICATION Damper Disc This invention relates to a damper disc applicable to a friction clutch disc of a land vehicle.

In a known type of damper disc, respective subplates are arranged between a radial flange of a hub splined to an output shaft and each of two side plates, which are a clutch plate and a retaining plate. A first friction member having small frictional force is arranged between the hub-flange and each sub-plate, and a second friction member having large frictional force is arranged between each side plate and each sub plate. In this construction, when a small torque is transmitted, and therefore the reiative torsion angle between the hub-flange and the side plates is small, sliding occurs on the surface of each first friction member, so that small hysteresis torque occurs.When the transmitted torque increases to a large value, and the torsion angle is thereby increased to large value, sliding occurs on the surface of each second friction member, so that large hysteresis torque occurs. In the disc in which the hysteresis torque changes as stated above, noises can be prevented during both idling and high power driving.

However in this known type of the damper disc, since the hub flange has large recesses through which extend stud pins connecting the sub-plates together and stop pins supported by the side plates, the strength of the hub flange is reduced by these large recesses. Therefore, it is impossible to form large and long openings in the flange for receiving long torsion springs for efficiently absorbing torque vibration; this has the disadvantage that the desired effect of absorbsion of torque vibration can not be obtained.

Accordingly, it is an object of the present invention to provide a damper disc, wherein the positions, shapes and sizes of the notches and recesses for the stop pins or stud pins are improved as compared with the prior known proposals.

With this object in view, the present invention provides a damper disc comprising a hub splined to an output shaft; a radial flange formed on the outer periphery of the hub; a pair of annular side plates disposed one at each side of the flange; torsion springs disposed in openings formed in the flange and the side plates and registering in the axial direction of the disc, said side plates being connected to the flange by the springs; a pair of annular sub-plates disposed between the side plates and the flange; stud pins connecting the sub-plates together; recesses formed at middle portions of the side edges of the openings in the flange, each stud pin extending through said each recess with a space between the stud pin and the side edge of the recess corresponding to a torsion angle for first hysteresis torque; stop pins connecting the radially outer portions of the side plates together; notches formed at outer edges of the openings in the flange, each stop pin extending through each notch with a space between the stop pin and the side edge of the notch corresponding to a maximum torsion angle; a friction member arranged between the subplates and the side plates, and having large frictional force; and a friction member arranged between the flange and the side plates, and having small frictional force.

Other and further objects, features and advantages of the invention will appear more fully from the following description of a preferred embodiment of the invention, as illustrated in the accompanying drawings, in which: Fig. 1 is a sectional view of a preferred embodiment of the clutch disc of the invention Fig. 2 is a fragmentary sectional view illustrating other parts of the clutch disc of Fig. 1; Fig. 3 is a fragmentary view of the clutch disc viewed in the direction of arrows Ill-Ill in Fig. 1, with certain parts cut away; Fig. 4 is a schematic enlarged view illustrating a part of Fig. 3; Fig. 5 is a sectional view taken along line V-V of Fig. 3; Fig. 6 is a graph explaining the relation between torque and torsion in the clutch disc of the invention; and Fig. 7 is a fragmentary schematic view of a known clutch disc comparable with Fig. 4.

Referring firstly to Fig. 1, a hub 1 comprises inner teeth 2 splined to an output shaft (not shown) and has a radial flange 3 on its outer periphery. A pair of annular side plates 5 and 6 are arranged one at each side of the flange 3.

Cushioning plates 8 are fixed at the radially outer portion of the side plate 5, which is a clutch plate, by means of rivets 7. A pair of annular friction facings 10 are fixed to the two faces of the plates 8 by rivets 11. The outer portions of the side plates 5 and 6 are connected to each other by stop pins 12. The plate 5 has a bent cylindrical flange 14 projecting away from the flange 3 and rotatably fitting onto the outer periphery of the hub 1 to which induction hardening is applied.

The plate 6, which is a retaining plate, has no such cylindrical flange. The inner edge of the plate 6 is positioned around the outer periphery of the hub 1 with a slight space therebetween.

A respective annular sub-plate 1 6 is arranged between the flange 3 and each of the side plates 5 and 6. A respective first friction member 1 5 is arranged between the radially inner portion of the flange 3 and each sub-plate 1 6. A respective second friction member 1 7 is arranged between each of the side plates 5 and 6 and the adjacent sub-plate 1 6. These friction members 1 5 and 1 7 are friction washers, wave springs or the like.

Referring now to Fig. 2, radially middle portions of both sub-plates 1 6 are tightly connected together by stud pins 1 8. The pins 1 8 push the sub-plates 1 6 strongly against second friction members 17, so that each second friction member 1 7 has a large frictional force. Said pushing force by the pins 1 8 reduces the pressure applied to each first friction member 15, so that the frictional force of each member 1 5, is small.

The surfaces of each first friction member 1 5 may be smooth, and the surfaces of each second member 1 7 may be rough, for achieving difference between the frictional forces thereof as stated above.

Referring back to Fig. 1, a torsion spring 20, which is a compressible coil spring, is thick and has a large diameter. A torsion spring 21, which is also a compressible coil spring, is thin and has a small diameter. These springs 20 and 21 each extend in a substantially circumferentiai direction of the disc (in other words, vertically with respect to Fig. 1), and are arranged in openings 24, 25 and 23 formed in the side plates 5 and 6 and in the flange 3 and registering in axial direction of the disc (in other words, transversely with respect to Fig. 1). The sub-plates 1 6 have recesses for the springs 20 and 21.

Referring to Fig. 3, three large springs 20, two small springs 21 and one spring 22 which is thinner than the springs 21, are disposed in the disc. Each large spring 20 and each of the small springs 21 and 22 are arranged one after the other with a constant spacing therebetween.

Three stop pins 12 are disposed respectively outside the small springs 22 and 21, and extend through notches 30 formed in the flange 3. Each notch 30 continues to the adjacent opening 26 for the spring 21 or the opening 31 for the spring 22. The notches 30 are surrounded by the outer edge 32 of the flange 3. Each sub-plate 1 6 has shallow recesses 40 in which the stop pins 40 can be dispaced without any contact with the sub-plates 1 6. The stud pins 18 are arranged adjacent both ends of each large spring 20; thus the disc has six stud pins 18. Each stud pin 18 extends through a respective recess 33 formed in the flange 3. As shown in Fig. 4, the recesses 33 are formed at middle portions of side edges 35 and 35' (Fig. 3) of the openings 23.In other words, portions 38 and 39 having radial length / and I' between each recess 33 and the inner and outer edges 36 and 37 of each opening 23 are not recessed. The ends of each spring 20 is designed to be supported by the un-recessed portions 38 and 39 during a twisting operation detailed later.

Referring to Fig. 5, circumferential spaces L, and L', are formed between each stop pin 12 and both side edges 41 and 41' of each notch 30 of the flange 3. The space L, and L'1 and other spaces detailed hereinafter are formed when the plates 5, 6 and 1 6 do not twist or torsionally turn with respect to the flange 3 as illustrated, and torsion angle D (see Fig. 6) is 00. The space L, corresponds to maximum torsion angle, e.g., 160 in Fig. 6, in the positive torsion direction. The space L', corresponds to maximum torsion angle, e.g. 80, in negative torsion direction. Spaces L2 and'2 are formed between each stud pin 18 and adjacent side edges 42 and 42' of the recesses 33 in the flange 3.The spaces L2 and L'2 correspond to a positive torsion angle of 12" and a negative torsion angle of 40, respectively, at which second hysteresis torque H starts to occur.

When the torsion angle D is 00, both ends of the springs 20 and 21 are supported by side edges 43 and 43' 44 and 44' of the openings in the side plates 5 and 6. Spaces L3 and L'3 are formed between both ends of the springs 20 and the side edges 35 and 35' of the openings in the flange 3.

The spaces L3 and L'3 correspond to positive and negative third torsion angies of 130 and 50.

Spaces4 andL'4 are formed between both ends of the springs 21 and side edges 45 and 45' of the openings in the flange 3. The spaces L4 and L'4 correspond to second torsion angles of 11 and 30. As shown in Fig. 3, both ends of the spring 22 are supported by the side edges of the openings 31,46 and 47 in the flange 3 and the side plates 5 and 6. Side edges of the openings in the sub-plates 1 6 are in contact with the ends of the springs 21 and 22, and are apart from the ends of the spring 20 with spaces therebetween, which correspond to a torsion angle of 10 (13 0-- 120, 50--40) or more.Said value 1 O is the difference of the torsion angle between the start of third torsion operation by the springs 20 and the start of the second hysteresis torque H.

Operation of the device proceeds as follows. In the situation, as illustrated in Figs. 1 to 5, where the torsion angle D is 00, when the facings 10 are pressed to a flywheel (not shown) of an engine by a pressure plate (not shown), torque is transmitted to the side plates 5 and 6, and the disc rotates in a direction R in Fig. 3. While the torque is a low value, the side plates 5 and 6 are connected to the sub-plates 16 by means of the second friction member 1 7 without any sliding, and sliding occurs on the surfaces of the members 1 5; as a result the side plates 5 and 6 twist with respect to the flange 3, in the rotating direction R of the disc in Fig. 3. By this twisting the small spring 22 is pressed by the left side edge in Fig. 4 of the opening 31 in the flange 3 and the right edges, in Fig. 3, of the openings 46 and 47 in the side plates 5 and 6.Thus, the torque is transmitted from the side plates 5 and 6 to the output shaft through the spring 22, the flange 3 and the hub 1. Although, the springs 20 and 21 travel together with the side plates 5 and 6, they do not contact with the side edges of the openings 23 and 26 in the flange 3. Therefore the torque is not transmitted through the springs 20 and 21. Since only one weak spring 22 operates as a spring for transmitting the torque in this operation, the rate of increase of the torque Twith respect to the torsion angle D of the plates 5 and 6 is low, as is shown in section a-h of torqueangle characteristic line X in Fig. 6. Further, a small first hysteresis torque h caused by said slide of the members 1 5 occurs in this operation as illustrated in Fig. 6. This operation continues until the torsion angle D reaches 11 0.

When the torsion angle D exceeds 11 , the springs, 21 having travelled the spaces L4 in Fig.

5, contact with the side edges 45 of the openings in the flange 3, and start to be compressed. By this compression, some of the torque is transmitted from the side plates 5 and 6 to the flange 3 through the springs 21. Since the torque is transmitted through three springs 21 and 22 in this operation the incline of the line X increases in section b-d.

When the torsion angle D exceeds 12", the stud pins 18 having travelled the spaces L2 in Fig.

5 contact with the side edges 42 of the recesses in the flange 3. After this contact (0 > 120), the sub-plates 1 6 are connected to the flange 3 rigidly in the rotating direction, and the side plates 5 and 6 twist with respect to the sub-plates 1 6 and the flange 3. Thus, slide occurs on the surfaces of the second friction members 1 7 having large frictional force, and the large second hysteresis torque H is produced in the area of the angle over 120.

When the torsion angle D exceeds 130, the springs, 20 having travelled the spaces La in Fig.

5, contact with the side edges 35 of the openings in the flange 3 and the strong springs 20 start to be compressed. Thus, torque is transmitted from the side plates 5 and 6 to the flange 3 through the springs 20. Since all of the springs 20, 21 and 22 are compressed in this operation, the incline of the line X increases in section d-e.

When the torsion angle D reaches 160, each stop pin 12 contacts with the side edge 41 of each notch 30, and further torsion is prevented.

When the torque Tdecreases to O kgm from the maximum value, the torsion angleD decreases to 00. During this decreasing operation, the incline of the line X changes twice at 130 and 11 , and the hysteresis torque changes once at 120. When the torque Tincreases in a negative direction from 0 kgm, each member operates similarly as above, the angle D increases to 80 in negative area. In this operation, the incline of the line X changes twice at 30 and 50, and the hysteresis torque changes once at 40.

According to the invention, as detailed hereinbefore, as the hysteresis torque changes, the noise during idling and high power driving of the engine can effectively be prevented.

Further, the invention has advantages that the maximum torsion angle can be quite large, and the sub-plates 1 6 can operate stably.

Referring to Fig. 7, a known flange 59, which is not within the invention, has a recess 55 through which a stop pin 53 extends. The recess 55 is formed at the portion outside and between two springs 51. Inner edge of the recess 55 is further recessed and formed into a recess 57 through which a stud pin 56 extends. The recesses 55 and 57 extend radially, from the outer edge of the flange 50 to the portion near the inner edge of the flange 50.

In this construction shown in Fig. 7, it is essential to form a spring seat portion 58 having long length I between the spring 51 and the recess 57 so that the flange 50 may steadily support the springs 51, and the flange 50 may not be deformed by the elastic force of the springs 51.

Therefore, adjacent pairs of springs 51 are positioned apart from each other with a long space /3 therebetween, which is a sum of the length 2/r of two spring seat portions 58 and a length 12 of the recess 57 (l3=2l1l2). Thus, a length 14 of the spring 51 and an opening should be set short, which results in disadvantage that a maximum torsion angle is small, and a torque vibration can not be effectively absorbed. Further, since the long space 13 should be formed between the two springs 51 for forming the recess 57, only a few e.g., three, recesses 57 and stud pins 56 can be employed in the disc.Therefore only three portions of each sub-plate is engaged to the flange 50 by the three stud pins 56, and large partial pressure is applied to the sub-plates by the pins 56. Thus, the sub-plates may be deformed, and an intended hysteresis torque characteristic may not be obtained.

In comparison with this known art, according to the disc of the invention in Fig. 4, since the recess 3 is formed between the inner and outer spring seat portions 38 and 39, a space /5 between two openings 23 and 31 (or 26) for the springs is same as a length of the spring seat portion 39, and is short. In other words, a portion 60 between the recess 33 and the opening 31 is formed only for radially connecting the two spring seat portions 38 and 39 together, and the portion 60 does not support the spring. Therefore, a length le of the portion 60 can be set short, and the space tB between two openings 23 and 31 (26) is short.Thus, each length of the openings 23, 31 and 26 and the springs 20,22 and 21 can be set long, which increases the maximum torsion angle, and thereby, the torque vibration can be absorbed effectively. Further, as the stud pins 1 8 and the recesses 33 do not cause increase in the space /5 between the openings, many, e.g., six, stud pins 1 8 can be employed in the disc as shown in Fig. 3. Therefore, the pressure by the flange 3 is divided and applied to the many portions of the sub-plates 1 6 through the stud pins 1 8. Thus, the sub-plates 1 6 are prevented from deformation, and the intended torque hysteresis characteristic can be obtained.

Referring to Fig. 4, since each notch 30 for the stop pin 1 2 is positioned outside the opening 31, (26), the strength of the spring seat portions 38 and 39 is not reduced by the recesses 30. Also by this advantage, the space /5 can be set short, and the maximum torsion angle can be set large.

Further the many stud pins 18 can be employed.

In a modification of the invention, two pairs of the stud pins 1 8 may be arranged respectively beside eachside edge of the two openings in the flange 3 which are opposite to each other with the centre of the disc therebetween. Each stud pin 1 8 may be arranged beside only one side edge of each opening. Such spring mechanism may be so employed that the incline of the line X changes once. In Fig. 3, portions 32 surrounding the openings 30 may be eliminated. A pair of coaxially-arranged springs having large diameter and small diameter may be employed instead of one spring 20, 21 or 22.

Although the invention has been described in its preferred form with a certain degree of detail, it is to be understood that the present disclosure of one preferred form may be changed in details of construction, and variations in the combination and arrangement of parts may be resorted to without departing from the scope of the invention as defined in the following claims.

Claims

1. A damper disc comprising a hub splined to an output shaft; a radial flange formed on the outer periphery of the hub; a pair of annular side plates disposed one at each side of the flange; torsion springs disposed in openings formed in the flange and the side plates and registering in the axial direction of the disc, said side plates being connected to the flange by the springs; a pair of annular sub-plates disposed between the side plates and the flange; stud pins connecting the sub-plates together; recesses formed at middle portions of the side edges of the openings in the flange, each stud pin extending through said each recess with a space between the stud pin and the side edge of the recess corresponding to a torsion angle for first hysteresis torque; stop pins connecting the radially outer portions of the side plates together; notches formed at outer edges of the openings in the flange, each stop pin extending through each notch with a space between the stop pin and the side edge of the notch corresponding to a maximum torsion angle; a friction member arranged between the subplates and the side plates, and having large frictional force; and a friction member arranged between the flange and the side plates, and having small frictional force.

2. A damper disc as claimed in claim 1 wherein some of the springs are distant from the side edges of the opening in the flange with spaces corresponding to a torsion angle which is iess than the maximum torsion angle, when the sideplate is not twisted.

3. A damper disc as claimed in claim 1 or 2 wherein six springs are employed, and six stud pins are arranged beside both ends of three springs.

4. A damper disc substantially as hereinbefore described, with reference to and as illustrated in Figs. 1 to 6 of the accompanying drawings.