Torque variation absorbing device

Abstract: A torque variation absorbing device includes a drive plate (2) connected to a drive shaft having a cmmon axis, a first fly-wheel (2a, 2b) and a second fly-wheel (6a, 6b) having the same axis as the drive plate (2) and being integrally connected, a damping mechanism arranged between the first fly-wheel (2a, 2b) and the second fly-wheel (6a, 6b), the damping mechanism including a coil spring (14) with a first spring seat (15a) fitted into one side of the coil spring (14) and a second spring seat (15b) fitted into the other side of the coil spring (14), a driven disk (18) contacting the first spring seat (15a) and rotating with the fly-wheels, a first elastic device (26a) provided on the driven disk (18) for interacting with the first of the spring seat (15a) and a second elastic device (25a) provided on the drive plate (2) for interacting with the second spring seat (15b).

Description: This invention relates to a torque variation absorbing device provided with an engine for use in an automotive vehicle or other vehicle. A prior art torque variation absorbing device having a driven disc, damper springs with spring seats and elastic means is disclosed in the document EP-A-0 258 112 which shows the features of the preamble of claim 1. A further prior art torque variation absorbing device is known from Japanese Utility Model Laid-Open Print No. 1-55339. This prior art, shown in Fig.6, discloses a damping mechanism 111 equipped with a coil spring 113 and two spring seats 114,115 fitted onto both sides of the coil spring 113. Each spring seat 114 and 115 is provided with a plural elastic portion 128,129 on its surface where the spring seats 114 and 115 contact a driven disk 117 and a drive plate (not shown) so as to reduce noise. Accordingly, even if excessive torque is transmitted to the damping mechanism 111 from an engine (not shown), the noise can be reduced. However, for example, when the spring seat 114 is in contact with the driven disk 117, the plural elastic portions 128,129 are constantly in compression. Therefore, the plural elastic portions 128,129 are partially and abnormally worn out. Also, when the engine (not shown) rotates quickly, the coil spring 113 is moved outerwardly by the centrifugal force of the rotation. In light of the above-mentioned drawbacks, the foregoing device disclosed that the axis of both spring seats 114 and 115 is off-set inwardly against an axis of the coil spring 113. However, since the plural elastic portions 122 and 129 are provided at the inner periphery of the plural spring seat 114 and 115, the off-set can not be maintained during the time the plural spring seats 114 and 115 are in contact with the driven disk 117 and the drive plate (not shown). It is an object of the present invention to provide an improved torque variation absorbing device so that the elastic portion will not be abnormally worn out when the spring seat is in contact with a driven disk and a drive plate. This object is achieved by the features of claim 1. BRIEF DESCRIPTION OF THE DRAWINGS These and other objects, features and advantages of the present invention will become fully apparent on reading the following detailed description with reference to the accompanying drawings, wherein like members bear like reference numerals, and wherein: FIG.1 is a partial cross sectional view of a torque variation absorbing device illustrating an embodiment of the present invention. FIG.2 is a sectional view of a torque variation absorbing device illustrating an embodiment of the present invention taken along the line A - A in Fig.1. FIG.3A through FIG.3D are a partially enlarged views of an elastic portion of the driven disk engageble with a spring seat illustrating an embodiment of the present invention taken along the line B - B in Fig.2. FIG.4A through FIG.4D are a partially enlarged view of an elastic portion of the driven disk engageble with a spring seat illustrating an embodiment of the present invention taken along the line C- C in Fig.2. FIG.5A through FIG.5D are a partially enlarged view of an elastic portion of the driven disk engageble with a spring seat illustrating an embodiment of the present invention taken along the line D- D in Fig.2. FIG.6 is a partial cross sectional view of a conventional torque variation absorbing device. DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS OF THE INVENTION In reference to Fig.1 and Fig.2, a drive plate 2 is composed of the first fly-wheel 2a,2b and drive side plates 2c,2d integrally connected to the both sides of the first fly-wheel 2a,2b by rivets 3,4. Each drive side plate 2c,2d is made of steel and is integrally rotated with a drive shaft (not shown). A ring gear which engages with a pinion gear (not shown) of a starter-moter (not shown) is formed at the outer periphery of the first fly-wheel 2a. A driven plate 6 has the same axis as the drive plate 2 and is arranged to be respectively rotatable with the drive plate 2 through a bearing 7. The driven plate 6 is composed of the second fly-wheel 6a and a driven plate 6b. The second fly-wheel 6a and a driven plate 6b are integrally connected by a bolt 10. A pin 8 is fitted into a bore of the second fly-wheel 6a so as to adjust the position of a clutch mechanism (not shown). A bore 9 is formed on the second fly-wheel 6a so that a clutch cover (not shown) can be fixed to the second fly-wheel 6a. A damping mechanism has a coil spring 14 with two spring seats 15a and 15b fitted on the ends of the coil spring 14. An elastic member 15c is fitted inside the coil spring 14 and is secured to either spring seat 15a or 15b or to both of the spring seats 15a and 15b. A torque limiter 12 is arranged between the second fly-wheel 6a and a cut-out portion 16 formed at an edge portion of the driven plate 6b. The torque limiter 12 has a frictional lining 17, a driven disk 18, a cone spring 19, a sub-plate 20, and a frictional lining 21. The rotational torque limiter 12 acts to absorb the torque variation through frictional loss when the cone spring 19 acts against the frictional lining 17 and 21. When the rotational torque is less than the frictional force determined by the cone spring 19, the driven disk 18, the drive plate 2 and the driven plate 6 integrally rotate. On the other hand, when the rotational torque is more than the frictional force determined by cone spring 19, the torque can not be transmitted due to movement slide between the driven disk 18 and the driven plate 6. A hysteresis mechanism is accommodated between the driven plate 6b and the drive plate 2c. The hysteresis mechanism is composed of a friction lining 22, a control plate 23 and a cone spring 24. The control plate 23 is ring-shaped and is partly bent, a top end of the bent portion 23a is engaged in a groove 24 formed on the driven plate 6b. The groove 24 is extended into a circumferencial direction of the driven plate 6b and is arch-shaped. The bending portion 23a rotationally moves in the groove 24 and is regulated by a side wall of the groove 24. The friction force generated on the surface of the friction lining 22 when the cone spring 24 urges the friction lining 22 into the drive plate 2c gives a hysteresis characteristic to the device. Plural elastic portions 25a and 25b, as shown in Fig.2, are snugly fitted on the drive plate 2c and 2d. The plural elastic portions 25a and 25b, for exampley, are made of a flexible rubber. Other plural elastic portions 26a and 26b are snugly fitted on both sides of the driven disk 18. Plural elastic portions 25a,25b,26a,26b are described below in detail. A supporting plate 27 is snugly fixed on the inside wall of the drive side plate 2c and 2d which are located on the inside of the first fly-wheel 2a. Elastic portions 25a and 25b are adhered on a top end of the suporting plate 27. In addition, the elastic portion 25a or 25b may be covered by the supporting plate 27. Also, elastic portions 25a and 25b are engaged with the drive spring seat 15a and 15b of the inner-side of the axis O₂ of spring seats 15a and 15b when the coil spring 14 is extended. Accordingly, the damping mechanism 11 is supported by the flexible plural elastic portion 25a and 25b. The driven disk 18 is circumferencially projected so that the driven disk 18 can be engaged with the plural spring seat 15a,15b. A supporting plate 30 fitted to the shape of the projecting portion 29 is snugly fitted on both sides of the driven disk 18 by rivets 31. An elastic portion 26a is held between one of the projecting portions 29 and the supporting plate 30. In the same way, an elastic portion 26b is held between the other of the projecting portions 29 and the supporting plate 30. Each elastic portion 26a and 26b is made of a rubber member and is adhered to the top end of the the supporting plate 30. In addition, the elastic portion 26a and 26b may be coated with the supporting plate 30. Also, the top end of each elastic portion 26a and 26b projects farther than the projecting portion 29 in the direction of the circumference. The contacting point between the driven disk 18 and the the drive spring seat 15a is set to be outward of an axis O₁ of the coil spring 14. In the above mentioned embodiment, the torque variation absorbing device of the present invention operates as follows. A rotational torque is transmitted to the driven plate 6 from the drive plate 2 through the damping mechanism 11, the torque limiter 12 and the hysteresis mechanism 13. When the drive plate 2 rotates relative to the driven plate 5 in the direction of arrow X, as shown in Fig.3A through 3D, Plural elastic portions 26a and 26b projected farther than the projecting portion 29 of the driven disk 18 in a circumferencial direction around the driven disk 18 and begine to contact or engage with a concave portion 15a' formed on the drive spring seat 15a. With additional engagement, the projecting portion 29 of the driven disk 18 directly contacts with the drive spring seat 15a. In a result, the coil spring 14 is compressed by the diven disk 18 and the rotational torque is transmitted to the driven plate 6 from the drive plate 2. Accordingly, each elastic portion 26a and 26b will not be abnormally worn out when the drive spring seat 15a is in contact with the driven disk 18. Also, since the coil spring 14 can be compressed inwardly, the off-set between the axis O₂ of the both spring seats 15a and 15b and the axis O₁ of coil spring 14 can be maintained. Fig.4A through 4D and Fig.5A through 5D illustrate the same operation as described above. On the other hand, when the driven disk 18 is released, the drive spring seat 15a begins to contact the elastic portions 25a and 25b integrated with the supporting plate 27. Thus, the noise can be reduced. Further, plural elastic portions 25a and 25b are in contact at the outerward portion of the drive spring seat 15a against an axis O₂ of both spring seats 15a and 15b, whereby the coil spring 14 is urged inwardly.

Claims: A torque variation absorbing device comprising: a drive plate (2) connected to a drive shaft, said drive plate (2) and said drive shaft having a common axis; a first fly-wheel (2a, 2b) and a second fly-wheel (6a) having the same axis as said drive plate (2) and being integrally connected; a damping mechanism arranged between said first fly-wheel (2a, 2b) and said second fly-wheel (6a), said damping mechanism including a coil spring (14) with a first spring seat (15a) fitted into one side of said coil spring (14) and a second spring seat (15b) fitted into the other side of said coil spring (14); a driven disk (18) having projecting portions (29) which contact said first spring seat (15a) and rotate with said fly-wheels (2a, 2b; 6a); a first elastic means provided on said driven disc (18) for interacting with said first spring seat (15a) a second elastic means provided on said drive plate (2) for interacting with said first spring seat (15a) characterized in that said first elastic means represented by plural elastic portions (26a, 26b) are held at said projecting portion (29) for engaging with said first spring seats (15a), wherein said projecting portions (29) on the driven disc (18) provide additional engagement with said first spring seats (15a) so as to avoid said elastic portions (26a, 26b) which project further than the projecting portions (29), becoming abnormally worn out. A torque variation absorbing device according to claim 1, wherein said first elastic means includes a supporting plate (30) fixed on said driven disk (18) and an elastic portion (26a, 26b) mounted thereon and provided with a cover of said supporting plate (30). A torque variation absorbing device according to claim 2, wherein said elastic portion (26a, 26b) projects farther than said driven disk (18) in a circumferential direction around said driven disk (18). A torque variation absorbing device according to claim 2, wherein said supporting plate (30) is fitted to said driven disk (18) by a rivet (31). A torque variation absorbing device according to claim 1, wherein said elastic means includes a supporting plate (27) fixed to said drive plate (2) and an elastic portion (25a, 25b) provided between said supporting plate (27) and said drive plate (2). A torque variation absorbing device according to claim 5, wherein said elastic portion (25a, 25b) is contacted by said spring seat (15a) under the condition that said coil spring (14) is previously compressed. A torque variation absorbing device according to claim 5, wherein said supporting plate (27) is fitted to said drive plate (2) by a rivet (28). A torque variation absorbing device according to claim 1, wherein said first elastic means includes an elastic portion (26a, 26b) having a projecting portion contacting a concave portion (15a') of said spring seat (15a) wherein the axis (O₂) of said projecting portion is set to be outward of an axis (O₁) of said spring seat (15a) in the direction of the radius. A torque variation absorbing device according to claim 1, wherein said second elastic means includes an elastic portion (25a, 25b) which is provided on said drive plate (2) in contact with said spring seat (15a) and which is located outside the axis of said coil spring (14).

Inventors: KAMIYA MASAKAZU, KOBAYASHI KIYONORI, KAMIYA, MASAKAZU, KOBAYASHI, KIYONORI
Applicants: AISIN SEIKI, AISIN SEIKI KABUSHIKI KAISHA
Application year: 1990
Main classification: F16D13
IPC codes: F16F15