JP2011179515A - Lockup device for torque converter - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a lockup device for a torque converter capable of positively suppressing vibration due to a coil spring. <P>SOLUTION: In the lockup device 7, in a state where each pair of first coil springs 174 and each pair of second coil springs 274 are compressed, torsional vibration is absorbed and damped in response to torsional rigidity of a compressible first coil springs 174 and second coil springs 274 by causing at least either coil spring of a first coil spring of either of the pair of the first coil springs 174, and a second coil spring 274 disposed in an inner peripheral part of the first coil spring of either of the pair of the first coil springs 174 to be incompressible. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a lockup device, and more particularly, to a lockup device for a torque converter for transmitting torque and absorbing / damping torsional vibration.

  In many cases, the torque converter is provided with a lock-up device for transmitting torque directly from the front cover to the turbine. The lockup device includes a piston that can be frictionally connected to the front cover, a retaining plate fixed to the piston, a plurality of pairs of torsion springs supported by the retaining plate, and a plurality of torsion springs in the rotational direction. And a driven plate elastically connected to the piston. The driven plate is fixed to the turbine (see Patent Document 1).

  Here, the piston divides the space between the front cover and the turbine in the axial direction, and when the friction facing that is annularly stretched around the outer periphery of the piston is pressed against the friction surface of the front cover, Torque is transmitted to the lockup device. Then, torque is transmitted from the lockup device to the turbine. At this time, torque fluctuations input from the engine are absorbed and attenuated by the plurality of torsion springs arranged on the outer peripheral portion of the lockup device.

JP2008-138797

  In the lockup device disclosed in Patent Document 1 (hereinafter referred to as a conventional lockup device), when a plurality of pairs of torsion springs are compressed, a plurality of pairs of torsion springs are based on the torsional characteristics of the pair of torsion springs. Torsional characteristics are determined. In other words, in order to determine the torsional characteristics of a plurality of pairs of torsion springs, it is necessary to set the torsional characteristics of a pair of torsion springs.

  The torsional characteristics indicate the relationship between the twist angle (rotation angle) of the pair of torsion springs and the amount of torque fluctuation that can be attenuated by the pair of torsion springs. For this reason, when a pair of torsion springs are compressed, torque fluctuations corresponding to the torsional rigidity of the pair of torsion springs are attenuated.

  In the conventional lock-up device, the torsional characteristics are linear. Therefore, if the predetermined torque fluctuation is attenuated using the torsional characteristics, the torsional rigidity has to be increased. However, if the torsional rigidity is increased too much, vibration due to the torsion spring may occur.

  In order to solve this problem, a configuration in which the torsion characteristic is set to a bilinear type has been considered. In the configuration in which the torsional characteristic is a bilinear type, the vibration caused by the torsion spring can be suppressed as compared with the configuration in which the torsional characteristic is linear. However, when the target attenuation amount of torque fluctuation is increased, there has been a problem that even the first torsional rigidity of the bilinear torsional characteristics cannot suppress the vibration caused by the torsion spring.

  On the other hand, if the first torsional rigidity of the bilinear torsional characteristics is reduced for the purpose of suppressing the vibration caused by the torsion spring when the target amount of torque fluctuation is large, the initial vibration can be suppressed, In order to ensure the target damping amount, it is necessary to increase the second torsional rigidity. For this reason, in this case, the ratio of the second torsional rigidity to the first torsional rigidity becomes large, and there is a possibility that new vibrations may occur in the inflection point of the torsion characteristics and in a range beyond the inflection point. That is, also in this case, a problem that the vibration caused by the torsion spring cannot be suppressed has occurred.

  The present invention has been made in view of such problems, and an object of the present invention is to provide a lock-up device for a torque converter that can reliably suppress vibration caused by a coil spring.

    A lockup device for a torque converter according to a first aspect is a device for transmitting torque and absorbing / damping torsional vibration. The lockup device includes an input rotation member, an output rotation member, a plurality of pairs of first coil springs, and a plurality of pairs of second coil springs.

  The first coil spring is compressed in the rotational direction by relative rotation between the input rotating member and the output rotating member. Each pair of first coil springs is arranged in series with each other. The second coil spring has a length shorter than that of the first coil spring, and is disposed on the inner periphery of the first coil spring.

  In this lockup device, engine torque is transmitted from the input rotating member to the output rotating member. At this time, when torsional vibration occurs, the torsional vibration is absorbed and damped by the plurality of pairs of first coil springs and the plurality of pairs of second coil springs.

  In this case, first, when compression of each pair of first coil springs is started, torsional vibrations are absorbed and damped according to the torsional rigidity of each pair of first coil springs (first stage torsional characteristics). . Next, when compression of each pair of first coil springs and each pair of second coil springs is started, torsional vibrations are generated according to the torsional rigidity of each pair of first coil springs and each pair of second coil springs. Is absorbed and attenuated (twist torsional characteristics). Finally, in a state where each pair of first coil springs and each pair of second coil springs are compressed, either one of the first coil springs of each pair of first coil springs, By making at least any one of the second coil springs arranged on the inner peripheral portion incompressible, the torsion is made according to the torsional rigidity of the compressible first coil spring and the second coil spring. Vibration is absorbed and damped (third stage torsional characteristics).

  In the present lock-up device, the torsional characteristics can be set to multistage, that is, a trilinear type. Thus, in this lockup device, the torsional rigidity can be gradually set larger by setting the torsional characteristics to the trilinear type. In particular, since the first stage torsional rigidity can be set small, vibration that may occur when the torsion angle is small can be suppressed.

  In this lockup device, the torsional characteristic is set to a trilinear type, so that the ratio of the torsional rigidity, for example, the second torsional rigidity to the first torsional rigidity is set as compared with the case where the torsional characteristic is set to the bilinear type. The ratio (N2 / N1) and the third torsional rigidity (N3 / N2) with respect to the second torsional rigidity can be set small. Thereby, the vibration which generate | occur | produces when each bending point in a torsion characteristic is exceeded can be suppressed.

  Furthermore, in this lockup device, at least one of the first coil springs of each pair of the first coil springs and the second coil springs arranged on the inner peripheral portion of the first coil springs. By making the coil springs incompressible, the third stage of torsional rigidity is formed, so that the trilinear torsional characteristics can be set without changing the size of the lockup device. That is, trilinear torsional characteristics can be set without changing the size of an existing lockup device.

Note that the trilinear torsional characteristics can be set regardless of the magnitude of the target attenuation of torque fluctuation. In particular, when the target attenuation amount of torque fluctuation is large, the above-described effect is prominent. In the lockup device for a torque converter according to claim 2, in the device according to claim 1, the first coil springs of each pair By bringing at least one of the first coil springs and the second coil spring disposed on the inner peripheral portion of the first coil spring into close contact with each other, Either one of the one coil springs and the second coil spring disposed on the inner periphery of the first coil spring are made incompressible.

  In this case, in a state where each pair of first coil springs and each pair of second coil springs are compressed, each pair of first coil springs is disposed on one side of each pair and on the inner peripheral portion of this first coil spring. When at least one of the coil springs on one side is in close contact with the line, the coil spring in close contact with the line becomes incompressible and does not contribute to torsional characteristics. Then, the torsional vibration is absorbed and damped according to the torsional rigidity of the compressible first and second coil springs (third stage torsional characteristics).

  In this lock-up device, a trilinear type is provided by close contact between at least one of the first coil springs on one side of each pair and the second coil spring disposed on the inner peripheral portion of the first coil spring on one side. Torsional characteristics can be set. Thus, in this lockup device, the shape of the first coil spring and the second coil spring (the total length of the coil spring, the distance between the lines, etc.) and the torsional rigidity of the first coil spring and the second coil spring are changed. The torsional characteristics of the trilinear type can be set easily. In addition, this lockup device can also obtain the above-described effects.

  In the lockup device for a torque converter according to a third aspect, in the device according to the second aspect, each pair of second coil springs has the same length. Also, any one of the second coil springs in each pair and the other one of the second coil springs in each pair have different torsional rigidity. Further, the second coil springs disposed on the inner peripheral portion of each pair of the first coil springs by bringing the second coil springs on one side of each pair into close contact with each other. Is made incompressible.

  In this case, when the first coil springs of each pair and the second coil springs of each pair are compressed, when the second coil springs on one side of each pair are in close contact with each other, the second coil springs in close contact with each other are It becomes incompressible and does not contribute to torsional characteristics. Then, the torsional vibration is absorbed and damped according to the torsional rigidity of the compressible first and second coil springs (third stage torsional characteristics).

  In this lockup device, the trilinear torsional characteristics can be set by the close contact between the second coil springs on one side of each pair. Thus, in this lockup device, the shape of the first coil spring and the second coil spring (the total length of the coil spring, the distance between the lines, etc.) and the torsional rigidity of the first coil spring and the second coil spring are changed. The torsional characteristics of the trilinear type can be set easily. In addition, this lockup device can also obtain the above-described effects.

  According to a lockup device for a torque converter according to a fourth aspect, in the device according to the third aspect, the torsional rigidity of each of the plurality of first coil springs is the same. Further, the torsional rigidity of the second coil springs arranged on the inner peripheral portions of the plurality of first coil springs is smaller than the torsional rigidity of the first coil springs.

  In this case, the torsional rigidity of each of the plurality of first coil springs is set to be the same, and the torsional rigidity of the second coil springs disposed on the inner peripheral portions of the plurality of first coil springs is set based on the torsional rigidity of the first coil springs. By setting it small, the torsional rigidity when the second coil spring contributes to the torsional characteristics can be changed gently. That is, a multistage characteristic in which the torsional rigidity does not change abruptly can be formed. In addition, this lockup device can also obtain the above-described effects.

  A lockup device for a torque converter according to a fifth aspect of the present invention is the device according to any one of the first to fourth aspects, further comprising rotation restricting means for restricting relative rotation between the input rotating member and the output rotating member. .

  In this case, relative rotation between the input rotating member and the output rotating member is restricted by the rotation restricting means. Then, the damper operation for absorbing and attenuating torsional vibrations by the first coil spring and the second coil spring stops. That is, the upper limit of the third stage torsional characteristic is set by the rotation restricting means. In this way, by setting the upper limit of the third stage torsional characteristics by the rotation restricting means, when the torsion angle exceeds a predetermined magnitude, the torque is reliably transferred from the input rotating member to the output rotating member. Can communicate. In addition, this lockup device can also obtain the above-described effects.

  According to the present invention, in the lock-up device for a torque converter, the vibration caused by the coil spring can be reliably suppressed.

1 is a partial cross-sectional view of a torque converter including a lockup device according to an embodiment of the present invention. The front fragmentary view of the lockup device. The front view of the said lockup apparatus. The partial external view of the spring holder of the lockup device. Sectional drawing of the said spring holder. The figure which shows the torsional characteristic of the trilinear type of the said lockup apparatus. The model figure at the time of the torsion spring action | operation of the said lockup apparatus.

  FIG. 1 is a partial sectional view of a torque converter 1 in which a lockup device according to an embodiment of the present invention is employed. An engine (not shown) is arranged on the left side of FIG. 1, and a transmission (not shown) is arranged on the right side of the figure. OO shown in FIG. 1 is a rotational axis of the torque converter and the lockup device. FIG. 2 is a partial front view of the lockup device. FIG. 6 is a diagram showing torsional characteristics of a trilinear type when a pair of first torsion springs and a pair of second torsion springs are actuated. FIG. 7 is a model diagram when a pair of first torsion springs and a pair of second torsion springs are operated at each stage of torsional characteristics.

[Overall configuration of torque converter]
FIG. 1 is a schematic longitudinal sectional view of a torque converter 1 in which an embodiment of the present invention is employed. The torque converter 1 is a device for transmitting torque from an engine crankshaft (not shown) to an input shaft (not shown) of a transmission. An engine (not shown) is arranged on the left side of FIG. 1, and a transmission (not shown) is arranged on the right side of FIG. OO shown in FIG. 1 is a rotating shaft of the torque converter 1. Further, the arrow R1 represents the rotational direction drive side of the torque converter 1, and the arrow R2 represents the opposite side (see FIG. 3).

  The torque converter 1 mainly includes a flexible plate (not shown) and a torque converter body 5. The flexible plate is made of a thin disk-shaped member, and is a member for transmitting torque and absorbing bending vibration transmitted from the crankshaft to the torque converter body 5. Therefore, the flexible plate has sufficient rigidity for torque transmission in the rotational direction, but has low rigidity in the bending direction.

  The torque converter body 5 includes a torus-shaped fluid working chamber 6 including three types of impellers (impeller 21, turbine 22, stator 23) and a lockup device 7.

  The front cover 11 is a disk-shaped member and is disposed in the vicinity of the flexible plate. A center boss 16 is provided at the inner peripheral end of the front cover 11. The center boss 16 is a cylindrical member extending in the axial direction, and is inserted into the center hole of the crankshaft.

  The inner peripheral part of the flexible plate is fixed to the front end surface of the crankshaft by a plurality of bolts. A plurality of nuts 12 are fixed to the outer peripheral side of the front cover 11 at equal intervals in the circumferential direction. Bolts screwed into the nut 12 fix the outer peripheral portion of the flexible plate to the front cover 11.

  An outer peripheral cylindrical portion 11 a extending toward the axial transmission side is formed on the outer peripheral portion of the front cover 11. The outer peripheral edge of the impeller shell 26 of the impeller 21 is fixed to the tip of the outer peripheral cylindrical portion 11a by welding. As a result, the front cover 11 and the impeller 21 form a fluid chamber filled with hydraulic oil. The impeller 21 mainly includes an impeller shell 26, a plurality of impeller blades 27 fixed inside the impeller shell 26, and an impeller hub 28 fixed to the inner peripheral portion of the impeller shell 26.

  The turbine 22 is disposed in the fluid chamber so as to face the impeller 21 in the axial direction. The turbine 22 mainly includes a turbine shell 30, a plurality of turbine blades 31 fixed to the impeller side surface, and a turbine hub 32 fixed to the inner peripheral edge of the turbine shell 30. The turbine shell 30 and the turbine hub 32 are fixed by a plurality of rivets 33.

  A spline that engages with the input shaft is formed on the inner peripheral surface of the turbine hub 32. Thereby, the turbine hub 32 rotates integrally with the input shaft.

  The stator 23 is a mechanism for rectifying the flow of hydraulic oil that returns from the turbine 22 to the impeller 21. The stator 23 is a member integrally manufactured by casting with resin, aluminum alloy or the like. The stator 23 is disposed between the inner periphery of the impeller 21 and the inner periphery of the turbine 22. The stator 23 mainly includes an annular stator shell 35 and a plurality of stator blades 36 provided on the outer peripheral surface of the shell 35. The stator shell 35 is supported by a cylindrical fixed shaft (not shown) via a one-way clutch 37. The fixed shaft extends between the outer peripheral surface of the input shaft and the inner peripheral surface of the impeller hub 28.

  The torus-shaped fluid working chamber 6 is formed in the fluid chamber by the shells 26, 30, and 35 of the impellers 21, 22, and 23 described above. An annular space 9 is secured between the front cover 11 and the fluid working chamber 6 in the fluid chamber.

  The one-way clutch 37 shown in the drawing has a structure using a ratchet, but may have a structure using a roller or a sprag.

  A first thrust bearing 41 is disposed between the inner peripheral portion of the front cover 11 and the turbine hub 32 in the axial direction. In the portion where the first thrust bearing 41 is provided, a first port 17 capable of communicating hydraulic oil in the radial direction is formed. The first port 17 communicates an oil passage provided in the input shaft, a first hydraulic chamber A (described later), and a space between the turbine 22 and the front cover 11. A thrust bushing 42 is disposed between the turbine hub 32 and the inner peripheral portion of the stator 23 (specifically, the one-way clutch 37). In the portion where the thrust bushing 42 is disposed, a second port 18 is formed on both sides in the radial direction so that hydraulic oil can communicate therewith. That is, the second port 18 makes the fluid passage between the input shaft and the fixed shaft and the fluid working chamber 6 communicate with each other. Further, a second thrust bearing 43 is arranged between the stator 23 (specifically, the shell 35) and the impeller 21 (specifically, the impeller hub 28) in the axial direction. In the portion where the second thrust bearing 43 is disposed, a third port 19 is formed on both sides in the radial direction so that hydraulic oil can communicate therewith. That is, the third port 19 communicates the oil passage between the fixed shaft and the impeller hub 28 and the fluid working chamber 6. Each oil passage is connected to a hydraulic circuit (not shown), and hydraulic oil can be supplied to and discharged from the first to third ports 17 to 19 independently.

[Structure of lock-up device]
As shown in FIGS. 1 to 3, the lockup device 7 is disposed in a space 9 between the turbine 22 and the front cover 11, and is a mechanism for mechanically connecting the two as required. . The lockup device 7 is disposed in a space between the front cover 11 and the turbine 22 in the axial direction. The lock-up device 7 has a disk shape as a whole, and divides the space 9 substantially in the axial direction. Here, a space between the front cover 11 and the lockup device 7 is a first hydraulic chamber A, and a space between the lockup device 7 and the turbine 22 is a second hydraulic chamber B.

  The lock-up device 7 has functions of a clutch and an elastic coupling mechanism, and mainly includes a piston 71, a drive plate 72 (retaining plate), a driven plate 73, and a plurality of torsion springs 74a and 74b (first torsion). A spring 174, a second torsion spring 274), and a spring holder 75.

  In FIG. 3, only the pair of torsion springs 74 a and 74 b, that is, the pair of first torsion springs 174 a and 174 b and the pair of second torsion springs 274 a and 274 b are denoted by reference numerals.

  The piston 71 is a member for engaging / disengaging the clutch, and further functions as an input member in the lockup device 7 as an elastic coupling mechanism. The piston 71 has a disc shape in which a central hole is formed. The piston 71 extends over the entire radius in the space 9 so as to divide the space 9 substantially in the axial direction. On the inner peripheral edge of the piston 71, an inner peripheral cylindrical portion 71b extending toward the axial engine side is formed. The inner peripheral cylindrical portion 71b is supported by the outer peripheral surface of the turbine hub 32 on the engine side so as to be movable in the rotational direction and the axial direction. Note that movement of the piston 71 toward the transmission side in the axial direction is restricted by contacting the transmission-side turbine hub 32.

  Further, an annular seal ring 32b that contacts the inner peripheral surface of the inner peripheral cylindrical portion 71b is provided on the outer peripheral surface of the turbine hub 32 on the engine side. As a result, an axial seal is provided at the inner peripheral edge of the piston 71. Further, a friction coupling portion 71 c is formed on the outer peripheral side of the piston 71. The friction coupling portion 71c is an annular portion having a predetermined length in the radial direction, and has a planar shape in which both axial surfaces are surfaces perpendicular to the axial direction. An annular friction facing 76 is stretched on the axial direction engine side of the friction coupling portion 71c. Thus, the clutch of the lockup device 7 is configured by the piston 71 and the flat friction surface of the front cover 11. A cylindrical portion or the like extending in the axial direction is not formed on the outer peripheral edge of the piston 71.

  The drive plate 72 is disposed on the axial transmission side of the outer peripheral portion of the piston 71. The drive plate 72 is an annular member made of sheet metal. The drive plate 72 includes a fixed portion 72a and a torque transmission portion 72b extending from the fixed portion 72a to the outer peripheral side. The fixing portion 72a is in contact with the axial transmission side surface of the piston 71, and is fixed to the piston 71 by a plurality of caulking 71d. The torque transmission part 72b extends from the fixed part 72a to the outer peripheral side. More specifically, the torque transmission part 72b is smoothly curved so as to be convex toward the axial transmission side from the radially inner side to the outer side, and then smoothly convex toward the axial engine side. It is curved and extends further to the axial transmission side. A plurality of engaging portions 72e are formed on the outer peripheral axial transmission side of the fixed portion 72a. The engaging portion 72e is a portion protruding from the other portion toward the axial transmission side.

  Between the rotational directions of the plurality of torque transmitting portions 72b, each is a spring accommodating portion 72d. In this embodiment, the spring accommodating part 72d is formed in four places. In FIG. 3, only one spring accommodating portion 72d is provided with a reference numeral.

  Torsion springs 74a and 74b, which are coil springs extending in the circumferential direction, are accommodated in the spring accommodating portion 72d. The torsion springs 74a and 74b are members for elastically connecting the piston 71 as an input member and the driven plate 73 as an output member in the rotation direction. The torsion springs 74a and 74b are composed of first torsion springs 174a and 174b and second torsion springs 274a and 274b. Specifically, a pair of first torsion springs 174a and 174b are arranged in each spring accommodating portion 72d so as to act in series in the rotational direction. The first torsion springs 274a and 274b are formed so that the torsional rigidity of each of the plurality of first torsion springs 274a and 274b is the same. Here, a total of eight first torsion springs 174a and 174b are used in total.

  Second torsion springs 274a and 274b are disposed on the inner peripheral portions of the pair of first torsion springs 174a and 174b disposed in each spring accommodating portion 72d. Specifically, the second torsion springs 274a and 274b are disposed so as to be movable in the rotational direction at the inner peripheral portions of the first torsion springs 174a and 174b. In total, eight second torsion springs 274a and 274b are used.

  Here, in each spring accommodating portion 72d, the signs of the torsion springs on the rotation direction R1 side are “74a”, “174a”, and “274a”, and the signs of the torsion springs on the rotation direction R2 side are “74b”. ”,“ 174b ”, and“ 274b ”.

  The second torsion springs 274a and 274b are formed so that the length of the second torsion springs 274a and 274b is shorter than the length of the first torsion springs 174a and 174b. Further, the second torsion springs 274a and 274b are formed so that the lengths of the plurality of second torsion springs 274a and 274b are the same.

  Further, the second torsion spring 274a is set such that the torsional rigidity of one of the second torsion springs 274a and 274b of each pair is different from the torsional rigidity of the other of the second torsion springs 274a and 274b of each pair. , 274b are formed. For example, the second torsion springs 274a and 274b are formed so that the torsional rigidity of the second torsion spring 274a on the rotation direction R1 side is smaller than the torsional rigidity of the second torsion spring 274b on the rotation direction R2 side.

  Here, a set of torsion springs composed of the first torsion spring 174a and the second torsion spring 274a acts in parallel in the rotation direction. Similarly, a set of torsion springs composed of a first torsion spring 174b and a second torsion spring 274b acts in parallel in the rotational direction. These two sets of torsion springs act in series in the rotational direction.

  The driven plate 73 is a member for transmitting torque from the torsion springs 74 a and 74 b to the turbine 22. The driven plate 73 is provided on the outer peripheral side of the turbine shell 30 of the turbine 22. The driven plate 73 is mainly composed of an attachment portion 73a and a plurality of claws 73b. The attachment portion 73a is fixed to the turbine shell 30 by welding, for example. The plurality of claws 73b are bent from the outer peripheral edge of the attachment portion 73a toward the axial direction engine. The claw 73b faces the torque transmission part 72b of the driven plate 72, and is inserted from the axial transmission side into the torque transmission part 72b that is curved so as to protrude toward the axial engine side. In this state, the claw 73b is in contact with both ends in the rotational direction of the pair of first torsion springs 174a and 174b disposed in each spring accommodating portion 72d.

  The driven plate 73 has stopper claws 73b. The stopper claw 73b extends from the inner peripheral edge of the attachment portion 73a toward the axial engine side. The stopper claw 73b is disposed between the engaging portions 72e of the adjacent drive plates 72. As a result, the relative rotation between the drive plate 72 and the driven plate 73 increases, and when the stopper claw 73b comes into contact with the engaging portion 72e in any of the rotational directions, the torsion springs 74a, 74b (174a, 174b, 274a, 274b) The compression, that is, the damper operation is stopped. Thus, the engaging portion 72e of the drive plate 72 and the stopper claw 73b of the driven plate 73 function as rotation restricting means. In other words, the rotation restricting means includes the engaging portion 72e of the drive plate 72 and the stopper claw 73b of the driven plate 73.

  The spring holder 75 is a support member for supporting the torsion springs 74a and 74b. Specifically, the spring holder 75 is a member for supporting the torsion springs 74a and 74b in the radial direction. The spring holder 75 is disposed so as to be rotatable relative to the piston 71 and the driven plate 73. Further, the spring holder 75 is disposed so as to be rotatable relative to the drive plate 72 and the driven plate 73.

  As shown in FIGS. 4 and 5, the spring holder 75 mainly has a support portion 175 and an engaging portion 275. The support portion 175 is a portion that supports the torsion springs 74a and 74b. The support part 175 has an outer peripheral side support part 175a, an inner peripheral side extension part 175b, and a connecting part (side support part) 175c.

  The outer periphery side support part 175a is a cylindrical part extended from the outer periphery of the connection part 175c to the axial direction transmission side. The outer peripheral side support part 175a is formed so that the curvature of the outer peripheral end continuously decreases as it moves away from the engaging part 275 in the rotational direction. And the outer peripheral side support part 175a is formed so that an outer peripheral end may become a plane in the rotation direction center part of the outer peripheral side support part 175a. In other words, as the outer peripheral side support portion 175a moves away from the engaging portion 275 in the rotational direction, the radial distance d from the outer peripheral surface of the outer peripheral side support portion 175a to the tip of the outer peripheral end of the outer peripheral side support portion 175a. However, it is formed so as to be continuously reduced.

  For example, when the outer peripheral side support part 175a is viewed in the rotational direction as shown in FIG. 5, the curvature of the outer peripheral end of the outer peripheral side support part 175a continuously decreases as the distance from the engagement part 275 increases in the rotational direction. (See FIGS. 5B to 5C). And the outer peripheral end of the outer peripheral side support part 175a is formed in the planar shape in the rotation direction center part of the outer peripheral side support part 175a (refer FIG.5 (d)). 5B, FIG. 5C, and FIG. 5D correspond to the V2 cross section of FIG. 4, the V3 cross section of FIG. 4, and the V4 cross section of FIG.

  Such an outer peripheral side support part 175a is disposed close to the outer peripheral side of the first torsion springs 174a and 174b, and supports the outer peripheral side of the first torsion springs 174a and 174b. Further, the outer peripheral side support portion 175 a is disposed on the outer peripheral side from the cylindrical portion of the torque transmission portion 72 b of the drive plate 72. Furthermore, the outer peripheral side support portion 175 a is disposed further on the outer peripheral side than the claw 73 b of the driven plate 73.

  The inner peripheral extension 175b is a portion extending radially inward from the inner peripheral side of the first torsion springs 174a, 174b. Specifically, the inner peripheral extension 175b is curved from the inner peripheral edge of the connecting portion 175c toward the first torsion springs 174a and 174b, and extends in a direction away from the inner peripheral side of the first torsion springs 174a and 174b. Part. In other words, the inner peripheral side extension 175b is a portion that curves from the inner peripheral edge of the connecting portion 175c to the axial transmission side and extends to the input shaft side.

  The inner peripheral extension 175 b is disposed between the piston 71 and the drive plate 72. In other words, the inner peripheral side extension 175 b, that is, the inner peripheral side of the spring holder 75 is positioned by the piston 71 and the drive plate 72. Specifically, the engine-side protrusion 72c of the drive plate 72 is fitted (in-joined) to the inner peripheral surface of the spring holder 75, for example, the tip 175d of the inner peripheral extension 175b. In this way, the spring holder 75 is positioned between the piston 71 and the drive plate 72.

  The connecting portion 175c is a substantially disk-shaped portion, and is disposed in contact with the axial transmission side of the friction connecting portion 71c of the piston 71. The connecting portion 175c is disposed between the piston 71 and the first torsion springs 174a and 174b in the axial direction. The connecting portion 175c is disposed between the piston 71 and the drive plate 72 in the axial direction. Specifically, the connecting portion 175c is disposed between the friction connecting portion 71c of the piston 71 and the torque transmitting portion 72b of the drive plate 72 in the axial direction. Further, the connecting portion 175 c is disposed between the piston 71 and the driven plate 73 in the axial direction. Specifically, the connecting portion 175 c is disposed between the piston 71 and the claw 73 b of the driven plate 73 in the axial direction.

  With such a structure, the spring holder 75 can support the torsion springs 74a and 74b that move radially outward by centrifugal force.

  The engaging portion 275 is a portion that engages with the first torsion springs 174a and 174b in the rotational direction. The engaging part 275 is formed integrally with the support part 175. The engaging portion 275 has a curved portion 275a and locking portions 275b and 275c.

  The curved portion 275a is a portion that connects the adjacent outer peripheral side support portion 175a and the adjacent connecting portion 175c. The curved portion 275a is formed integrally with the outer peripheral side support portion 175a and the connecting portion 175c.

  The locking portions 275b and 275c are portions that lock the first torsion springs 174a and 174b in the rotation direction. The locking portions 275b and 275c are formed by bending both ends of the bending portion 275a inward. For example, the locking portion 275b is a claw portion where the outer peripheral end of the bending portion 275a is bent toward the axial engine side. Moreover, the latching | locking part 275c is a nail | claw part which cut and raised the inner peripheral end of the curved part 275a to the axial direction transmission side. These locking portions 275b and 275c are disposed between the rotation directions of the pair of first torsion springs 174a and 174b in each spring accommodating portion 72d.

  Such a spring holder 75 is C-shaped with one axial side open in the longitudinal section. The spring holder 75 functions as an intermediate float body. Here, torque is transmitted from the first torsion springs 174a, 174b to the spring holder 75 via the engaging portions 275, for example, the locking portions 275b, 275c. When the second torsion springs 274a and 274b are compressed, the spring holder 75 receives torque transmission not only from the first torsion springs 174a and 174b but also from the second torsion springs 274a and 274b.

[Torque converter operation]
Immediately after the engine is started, the hydraulic oil is supplied into the torque converter body 5 from the first port 17 and the third port 19, and the hydraulic oil is discharged from the second port 18. The hydraulic oil supplied from the first port 17 flows through the first hydraulic chamber A to the outer peripheral side, passes through the second hydraulic chamber B, and flows into the fluid working chamber 6. For this reason, the piston 71 moves to the axial direction engine side due to the hydraulic pressure difference between the first hydraulic chamber A and the second hydraulic chamber B. That is, the friction facing 76 is separated from the front cover 11 and the lock-up is released. When the lockup is released as described above, torque transmission between the front cover 11 and the turbine 22 is performed by fluid drive between the impeller 21 and the turbine 22.

[Operation of lock-up device]
When the speed ratio of the torque converter 1 increases and the input shaft reaches a certain rotation speed, the hydraulic oil in the first hydraulic chamber A is discharged from the first port 17. As a result, due to the hydraulic pressure difference between the first hydraulic chamber A and the second hydraulic chamber B, the piston 71 is moved to the front cover 11 side, and the friction facing 76 is pressed against the flat friction surface of the front cover 11. As a result, the torque of the front cover 11 is transmitted from the piston 71 to the driven plate 73 via the drive plate 72 and the torsion springs 74a and 74b. Further, torque is transmitted from the driven plate 73 to the turbine 22. That is, the front cover 11 is mechanically coupled to the turbine 22, and the torque of the front cover 11 is directly output to the input shaft via the turbine 22.

  When the torsional vibrations 74a and 74b are repeatedly compressed as the torsional vibration is input as described above, the torsion springs 74a and 74b are moved radially outward by the centrifugal force, and the outer peripheral side support portion 175a of the spring holder 75 is moved. Slide on. However, since the spring holder 75 is a member that moves in the rotational direction together with the torsion springs 74a and 74b, the sliding resistance between the two members is greatly reduced, and the torsional vibration damping performance is sufficiently exhibited.

[Torsional vibration damping characteristics of lock-up device]
In the lockup coupled state described above, the lockup device 7 transmits torque and absorbs and attenuates torsional vibration input from the front cover 11. Specifically, as shown in FIG. 6, when a torsional vibration is input from the front cover 11 to the lockup device 7 and a torsion angle θ between the drive plate 72 and the driven plate 73 is generated, the first torsion spring 174a. , 174 b are compressed in the rotational direction between the drive plate 72 and the driven plate 73. This state is referred to as a first compressed state J1. Specifically, the first torsion springs 174 a and 174 b are compressed in the rotational direction between the torque transmission portion 72 b of the drive plate 72 and the claw 73 b of the driven plate 73. At this time, the spring holder 75 is moved in the compression direction by the torsion springs 74 a and 74 b and rotates relative to the drive plate 72 and the driven plate 73.

  In this state, when the twist angle θ increases, the two second torsion springs 274 a and 274 b of each pair come into contact with the drive plate 72 and the driven plate 73. This state corresponds to the first bending point P1 in FIG. Then, each pair of first torsion springs 174 a and 174 b and each pair of second torsion springs 274 a and 274 b are compressed in the rotational direction between the drive plate 72 and the driven plate 73. This state is referred to as a second compressed state J2. Specifically, the first torsion springs 174 a and 174 b and the second torsion springs 274 a and 274 b are compressed in the rotational direction between the torque transmission portion 72 b of the drive plate 72 and the claw 73 b of the driven plate 73. At this time, the spring holder 75 is moved in the compression direction by the torsion springs 74 a and 74 b and rotates relative to the drive plate 72 and the driven plate 73.

  In this state, when the torsion angle θ further increases, one of the two second torsion springs 274a and 274b of each pair, that is, the second torsion spring 274a having a lower torsional rigidity comes into close contact with each other. This state corresponds to the second bending point P2 in FIG. Here, when the second torsion spring 274a having the lower torsional rigidity is in close contact with the line, not only the second torsion spring 274a in close contact with the line but also the first torsion spring having the second torsion spring 274a on the inner peripheral portion. 174a is also incompressible. Then, the other of the two second torsion springs 274a and 274b of each pair, that is, the second torsion spring 274b having higher torsional rigidity, and the first of each pair having the second torsion spring 274b on the inner periphery. The torsion spring 174 b is compressed between the drive plate 72 and the driven plate 73 in the rotational direction. This state is referred to as a third compressed state J3. Specifically, the first torsion spring 174 b and the second torsion spring 274 b are compressed in the rotational direction between the torque transmitting portion 72 b of the drive plate 72 and the claw 73 b of the driven plate 73. At this time, the spring holder 75 is moved in the compression direction by the torsion springs 74 a and 74 b and rotates relative to the drive plate 72 and the driven plate 73.

  When the twist angle θ further increases in this state, the stopper claw 73 b of the driven plate 73 finally comes into contact with the engaging portion 72 e of the drive plate 72. This state corresponds to the state of the third bending point P3 in FIG. Then, the compression of each pair of first torsion springs 174b in operation and each pair of second torsion springs 274b in operation stop. This state is referred to as a compression stop state P3. That is, the damper operation of the torsion springs 74a, 74b (174a, 174b, 274a, 274b) is stopped.

  The torsional characteristics when the torsion springs 74a and 74b (174a, 174b, 274a, and 274b) operate as described above will be described below. In order to facilitate the description, the description will be given here using the torsional characteristics of the pair of torsion springs 74a and 74b (174a, 174b, 274a, 274b).

  As shown in FIGS. 6 and 7, in the first compressed state J1, the torsional rigidity N11 (= 1 / {(1 / K1 + 1 / K1)} == the two first torsion springs 174a and 174b arranged in series. 1 / (2 / K1)) is set as the torsional rigidity N1 of the system. Then, the first gradient D1 of torsional characteristics is set based on the torsional rigidity N1 of this system. Next, in the second compressed state J2, the torsional rigidity N21 (= K1 + K2) of the pair of first torsion spring 174a and the second torsion spring 274a arranged in parallel with another set of the first torsion spring 174a and the second torsion spring 274a. The torsional stiffness N2 (= 1 / (1 / N21 + 1 / N22) = 1 / [1 by combining with the torsional stiffness N22 (= K1 + K2 ′; K2 <K2 ′) of the first torsion spring 174b and the second torsion spring 274b. / {1 / (K1 + K2)} + 1 / {1 / (K1 + K2 ′)}]). Then, the second gradient D2 of torsional characteristics is set based on the torsional rigidity N2 of this system. Subsequently, when the second torsion spring 274a comes into close contact with each other and shifts from the second compressed state J2 to the third compressed state J3, a pair of the first torsion spring 174b and the second torsion spring arranged in parallel. The torsional rigidity N33 (= K1 + K2 ′) of 274b is set as the torsional rigidity N3 of the system. Then, based on the torsional rigidity N3 of this system, the third gradient D3 of torsional characteristics is set. In this way, the trilinear torsional characteristics are set.

  Finally, when transitioning from the third compression state J3 to the compression stop state P3, the torsional angle θ of the torsional characteristics reaches the maximum torsional angle θ. The torque when the torsion angle θ reaches the maximum torsion angle θ is the maximum torque in the torsional characteristics.

  The torsional characteristics shown here are the torsional characteristics of the pair of first torsion springs 174a and 174b and the pair of second torsion springs 274a and 274b disposed on the inner periphery of the pair of first torsion springs. Therefore, the torsional characteristics of the lockup device 7 as a whole, that is, the torsional characteristics of the plurality of pairs of first torsion springs 174a and 174b and the plurality of pairs of second torsion springs 274a and 274b are set to the torsional characteristics shown here. The

[Advantageous effects of torsional vibration damping characteristics]
In the present lock-up device 7, the torsional characteristics can be set to multistage, that is, a trilinear type. By setting the torsional characteristics to the trilinear type in this way, the torsional rigidity N1, N2, and N3 that change according to the torsion angle θ can be set to gradually increase without abrupt change. . In particular, since the first-stage torsional rigidity N1 can be set small, vibration that may occur when the torsion angle θ is small can be suppressed.

  Specifically, in the present lockup device 7, the torsional characteristic is set to a trilinear type, so that the torsional rigidity ratio, for example, the second to the first torsional rigidity is set as compared with the case where the torsional characteristic is set to the bilinear type. The torsional rigidity ratio (N2 / N1) and the third torsional rigidity (N3 / N2) with respect to the second torsional rigidity can be set small. Thereby, the vibration which generate | occur | produces when each bending point in a torsion characteristic is exceeded can be suppressed.

  Further, in the present lock-up device 7, either one of the first torsion springs 174a and 174b of each pair and the second torsion springs 274a and 274b disposed on the inner peripheral portion of the first torsion spring. Since the third stage torsional rigidity is formed by making at least one of the torsion springs incompressible, the trilinear torsional characteristics are set without changing the size of the lockup device. be able to.

  Further, in the present lock-up device 7, the trilinear torsional characteristics can be set by the close contact between the second torsion springs 274a and 274b on one side of each pair. Thus, in this lockup device 7, the shapes of the first torsion springs 174a and 174b and the second torsion springs 274a and 274b (the total length of the torsion springs, the distance between the lines, etc.), the first torsion springs 174a and 174b, By simply changing the torsional rigidity of the two torsion springs 274a and 274b, the torsional characteristics of the trilinear type can be easily set.

  Further, in the present lock-up device 7, the torsional rigidity of each of the plurality of first torsion springs 174a and 174b is set to be the same, and the second torsion spring disposed at the inner peripheral portion of each of the plurality of first torsion springs 174a and 174b. By setting the torsional rigidity of 274a and 274b to be smaller than the torsional rigidity of the first torsion springs 174a and 174b, the torsional rigidity when the second torsion springs 274a and 274b contribute to the torsional characteristics can be changed gently. . That is, a multistage characteristic in which the torsional rigidity does not change abruptly can be formed.

  Furthermore, in this lockup device 7, the upper limit of the third stage torsional characteristic is set by the rotation restricting means 72e and 73c. In this way, by setting the upper limit of the third stage torsional characteristics by the rotation restricting means 72e and 73c, when the torsional angle θ exceeds a predetermined magnitude, the torque is changed from the input side to the output side. It can be transmitted reliably.

[Advantageous effect of spring holder]
In the spring holder 75, since the curvature of the outer peripheral end of the outer peripheral side support portion 175a continuously decreases as the outer peripheral end of the outer peripheral side support portion 175a moves away from the engaging portion in the rotational direction, the generation of centrifugal force Accordingly, the stress concentration that can occur in the spring holder 75 can be reduced. In particular, in the central portion in the rotational direction of the outer peripheral side support portion 175a, the outer peripheral end of the outer peripheral side support portion 175a is formed in a planar shape, so that the stress concentration that can occur in the spring holder 75 due to the generation of centrifugal force, It can be surely reduced.

  Further, in this spring holder 75, the lockup device 7 is easily assembled from a portion with a small curvature at the outer peripheral end of the outer peripheral side support portion 175a of the spring holder 75 or a flat portion at the center in the rotational direction of the outer peripheral side support portion 175a. be able to.

  Further, in this spring holder 75, since the connecting portion 175c is disposed between the piston 71 and the torsion springs 74a and 74b in the axial direction, the connecting portion 175c is difficult to buckle and the strength of the spring holder 75 is improved. can do.

  Further, in this spring holder 75, the inner peripheral extension 175b becomes difficult to buckle due to the curved portion from the connecting portion 175c toward the torsion springs 74a and 74b, and the strength of the spring holder 75 can be improved. . Further, since the inner peripheral side extension 175b extends in a direction away from the inner peripheral side of the torsion springs 74a and 74b, the bending rigidity in the radial direction of the spring holder 75 can be increased.

  Further, in this spring holder 75, the engaging portion 275 of the spring holder 75 is formed with locking portions 275b and 275c formed by bending both ends of the curved portion 275a inward. The torsion springs 74a and 74b can be securely locked to 275c. Further, since the locking portions 275b and 275c are formed by bending both ends of the curved portion 275a inward, the locking portions 275b and 275c are difficult to buckle, and the strength of the spring holder 75 is improved. Can do. Then, the bending rigidity in the radial direction of the locking portions 275b and 275c can be increased.

[Other Embodiments]
(A) In the said embodiment, although the example in the case of transfering from the 2nd compression state J2 to the 3rd compression state J3 by the line | wire close_contact | adherence of the 2nd torsion spring 274a was shown, such a compression state was shown. The transition can also be realized by the close contact between the first torsion springs 174a and 174b. For example, the torsional rigidity of one of the paired first torsion springs 174a and 174b and the torsional rigidity of either of the paired first torsion springs 174a and 174b are set to different rigidity. Then, in the second compression state J2, the compression state is changed from the second compression state J2 to the third compression state by generating line-to-line contact with one of the first torsion springs 174a and 174b that make a pair. You can move to J3. That is, the third gradient D3 of torsional characteristics can be set. Even in this case, the trilinear torsional characteristics can be set.

  INDUSTRIAL APPLICABILITY The present invention can be used for a torque converter lockup device for transmitting torque and absorbing / damping torsional vibration.

7 Lock-up device 71 Piston 72 Drive plate 73 Driven plate 74, 74a, 74b Torsion springs 174, 174a, 174b First torsion springs 274, 274a, 274b Second torsion spring 75 Spring holder 175 Support portion 175a Outer peripheral side support portion 175c Side surface Support part 175b Inner peripheral side extension part 275 Engagement part 275a Bending part 275b, 275c Locking part 72e, 73c Rotation restricting means D1 First gradient of torsion characteristics D2 Second gradient of torsion characteristics D3 Third gradient of torsion characteristics

Claims (5)

A torque converter lockup device for transmitting torque and absorbing / damping torsional vibrations,
An input rotating member;
An output rotating member;
A plurality of pairs of first coil springs compressed in the rotational direction by relative rotation between the input rotating member and the output rotating member;
A second coil spring having a length shorter than the length of the first coil spring and disposed on an inner peripheral portion of the first coil spring;
With
The first coil springs of each pair are arranged in series with each other;
In a state where each pair of the first coil springs and each pair of the second coil springs are compressed, either one of the first coil springs of each pair of the first coil springs, The first coil spring and the second coil that are compressible by making at least one of the second coil springs disposed on the inner periphery of the first coil spring incompressible. Absorbs and attenuates torsional vibration according to the torsional rigidity of the spring.
Torque converter lockup device. At least one of the first coil spring of any one of the first coil springs of each pair and the second coil spring disposed on the inner peripheral portion of the one of the first coil springs. The first coil spring and the second coil spring disposed on the inner periphery of the first coil spring are compressed by bringing the coil springs in close contact with each other. Disabling,
The lockup device for a torque converter according to claim 1. Each pair of the second coil springs has the same length.
One of the second coil springs of each pair and the other of the second coil springs of each pair have different torsional rigidity,
Any one of the second coil springs of each pair is disposed in close contact with each other, thereby being disposed on the inner peripheral portion of the one of the first coil springs and the one of the first coil springs. Making the second coil spring incompressible,
The lockup device for a torque converter according to claim 2. Each of the first coil springs of each pair has the same torsional rigidity,
Each of the second coil springs in each pair has a torsional rigidity smaller than that of the first coil springs.
The lockup device for a torque converter according to claim 3. A rotation restricting means for restricting relative rotation between the input rotating member and the output rotating member;
The torque converter lockup device according to any one of claims 1 to 4, further comprising:

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