JP2004239365A - Torque damper of hydraulic transmission - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a torque damper of a hydraulic transmission capable of firmly supporting a damper spring generating a large centrifugal force during transmission, easily manufacturable, and capable of being reduced in weight and cost. <P>SOLUTION: This torque damper of a hydraulic transmission comprises a cylindrical rim 25b formed by bending at the outer peripheral end part of a clutch piston 25, an annular spring holding member 30 fixed to the clutch piston 25 to demarcate an annular spring storage groove 31 in association with the rim 25b, and a plurality of damper springs 32A and 32B stored in the spring storage groove 31. A first transmission claw 33 inserted between the damper springs 32A and 32B together with the second transmission claws 34A and 34B of an impeller 3 and stopper parts 30b and 30b' limiting the deformations of the damper springs 32A and 32B by the contact thereof with the second transmission claws 34A and 34B when a torque of a specified value or higher is applied between the clutch piston 25 and the turbine impeller 3 are formed on the spring holding member 30. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
According to the present invention, a plurality of damper springs are annularly arranged and accommodated in an annular spring accommodating groove formed in a clutch piston of a lock-up clutch, and a plurality of first transmission claws inserted between adjacent damper springs are provided. A plurality of second transmission claws, which are provided on the clutch piston and inserted between the adjacent damper springs together with the first transmission claws, are provided on the turbine impeller, and an impact torque applied between the clutch piston and the turbine impeller is deformed by the damper spring. The present invention relates to an improvement in a torque damper of a hydraulic power transmission device, which is configured to buffer the vibration.
[0002]
[Prior art]
Conventionally, the following is known as a torque damper of such a fluid transmission device.
[0003]
(1) An annular spring receiving groove for holding a damper spring is defined by a side surface of a clutch piston and a U-shaped section of a spring holding member fixed to the clutch piston (see Patent Document 1).
[0004]
(2) An annular spring receiving groove for holding a damper spring is formed by a rim having an arcuate cross section formed on the outer periphery of the clutch piston and a spring holding member fixed to the clutch piston and opposed to the rim in the radial direction. What was defined (refer to patent document 2).
[0005]
[Patent Document 1]
JP-A-2002-70949
[0006]
[Patent Document 2]
JP-A-8-49757
[0007]
[Problems to be solved by the invention]
By the way, in the above (1), the large centrifugal force generated in the damper spring during transmission is supported by a spring holding member separate from the clutch piston, so that the spring holding member is thick and rigid. However, there is a drawback that the cost and weight increase. In the above-mentioned (2), the large centrifugal force of the damper spring is received by the rim having an arc-shaped cross section integrally formed on the outer periphery of the thick and rigid clutch piston, so that the damper spring cannot be firmly supported. What can be done, it is not easy to form a U-shaped cross section on the rim of the outer periphery of the thick clutch piston in terms of molding, so that cost reduction cannot be satisfied.
[0008]
The present invention has been made in view of such circumstances, and can strongly support a damper spring that generates a large centrifugal force during transmission, and is easy to manufacture, and can be reduced in weight and cost. It is another object of the present invention to provide a torque damper for a fluid transmission device.
[0009]
[Means for Solving the Problems]
In order to achieve the above object, the present invention provides an annular spring receiving groove formed in a clutch piston of a lock-up clutch, in which a plurality of damper springs are annularly arranged and housed, and inserted between adjacent damper springs. A plurality of first transmission claws provided on a clutch piston, and a plurality of second transmission claws inserted between adjacent damper springs together with the first transmission claws on a turbine impeller. A cylindrical rim bent at the outer peripheral end of the piston and extending toward the turbine impeller; an annular spring holding member fixed to the clutch piston to cooperate with the rim to define an annular spring receiving groove; And a plurality of damper springs housed in the spring housing grooves and arranged in an annular shape. A stopper is formed on the member to limit the deformation of the damper spring by contacting the second transmission claw when a torque greater than a predetermined value is applied between the first transmission claw, the clutch piston and the turbine impeller. Is a first feature.
[0010]
According to this first feature, the large centrifugal force generated in the damper spring during transmission can be strongly supported by the thick and relatively high rigidity rim, and the rim is connected to the outer peripheral end of the clutch piston. Since the portion is formed into a cylindrical shape, the forming is easy. Since the spring holding member that regulates the movement of the damper spring toward the turbine impeller does not require a large holding force, it can be formed of a relatively thin steel plate. In addition, since the deformation of the damper spring is limited by the cooperation of the stopper portion and the second transmission claw, the damper spring can be protected from overload, and as a result, the torque damper is highly durable, easy to manufacture and lightweight. Can be provided at low cost.
[0011]
Further, according to the present invention, in addition to the first feature, the spring holding member extends radially outward from an inner diameter portion of the damper spring along a side surface of the damper spring opposite to the clutch piston. A second feature is that a plurality of arc-shaped holding walls that cover the side surfaces substantially half-circle are formed integrally, and the end of each holding wall in the rotation direction is the stopper.
[0012]
According to the second feature, the lateral movement of the damper spring can be reliably restricted by the retaining wall, and the retaining wall cooperates with the second transmission claw to limit the amount of compression of the damper spring. Since the stopper member also serves as a stopper member, a dedicated stopper member is not required, and the cost can be reduced.
[0013]
Further, according to the present invention, in addition to the first or second feature, a third feature is that a wear-resistant annular protective plate for covering an outer peripheral surface of the damper spring is fixed to the clutch piston.
[0014]
According to the third feature, when the damper spring expands and contracts due to the generation of centrifugal force, the friction between the damper spring and the rim can be avoided to prevent the rim from being worn. The durability can be improved without performing any treatment.
[0015]
Further, in the present invention, in addition to the third feature, a fourth feature is that the inner peripheral ends of the spring holding member and the protection plate are both overlapped with the clutch piston and fixed by rivets.
[0016]
According to the fourth feature, the spring holding member and the protection plate can be fixed to the clutch piston at a stroke, so that an increase in cost due to the fixing of the protection plate can be avoided.
[0017]
BEST MODE FOR CARRYING OUT THE INVENTION
Embodiments of the present invention will be described below based on preferred embodiments of the present invention shown in the accompanying drawings.
[0018]
FIG. 1 is a longitudinal sectional side view of a torque converter with a torque damper according to an embodiment of the present invention, FIG. 2 is a cross-sectional view taken along line 2-2 of FIG. 1, and FIG. 3 illustrates the operation of the torque damper. FIG. 4 is a sectional view showing a modified example of the hub of the clutch piston of FIG.
[0019]
First, in FIG. 1, a torque converter T as a fluid transmission includes a pump impeller 2, a turbine impeller 3 opposed thereto, and a stator impeller 4 disposed between the inner peripheral portions thereof. A circulation circuit 6 for transmitting power by operating oil is defined between the three impellers 2, 3, and 4.
[0020]
A side cover 5 that covers an outer surface of the turbine impeller 3 is integrally connected to the pump impeller 2 by welding. A connection boss 7 is welded to the outer peripheral surface of the side cover 5, and a driving plate 8 connected to the crankshaft 1 is fixed to the boss 7 with bolts 9. A thrust needle bearing 36 is interposed between the hub 3 h of the turbine impeller 3 and the side cover 5. Reference numeral 15 denotes a starting ring gear welded to the outer peripheral surface of the pump impeller 2.
[0021]
An output shaft 10 arranged coaxially with the crankshaft 1 is arranged at the center of the torque converter T. The output shaft 10 is spline-fitted to the hub 3 h of the turbine impeller 3 and supports the center of the side cover 5. The cylinder 5 a is rotatably supported via a bearing bush 18. The output shaft 10 is a main shaft of a multi-stage transmission (not shown).
[0022]
A cylindrical stator shaft 12 that supports a hub 4h of the stator impeller 4 via a freewheel 11 is disposed on the outer periphery of the output shaft 10, and the relative rotation between the output shaft 10 and the stator shaft 12 is provided. A bearing bush 13 that allows the pressure is provided. The outer end of the stator shaft 12 is non-rotatably supported by the transmission case 14.
[0023]
Thrust needle bearings 37, 37 'are interposed between the hub 4h of the stator impeller 4 and the hubs 2h, 3h of the pump impeller 2 and the turbine impeller 3 opposed thereto.
[0024]
An auxiliary drive shaft 20 connected to the pump impeller 2 is disposed on the outer periphery of the stator shaft 12 so as to be relatively rotatable. An oil pump 21 for supplying working oil to the torque converter T is provided by the auxiliary drive shaft 20. Driven.
[0025]
The turbine impeller 3 and the side cover 5 define a clutch chamber 22 therebetween, and a lock-up clutch L capable of directly connecting the turbine impeller 3 and the side cover 5 is housed in the clutch chamber 22. The clutch piston 25, which is a main component of the lock-up clutch L, is disposed in the clutch chamber 22 so as to partition the clutch chamber 22 into an inner chamber 22a on the turbine impeller 3 side and an outer chamber 22b on the side cover 5 side.
[0026]
The clutch piston 25 includes an annular web 25a bulged on the side cover 5 side, and a cylindrical rim 25b bent from the outer peripheral edge of the web 25a to the turbine impeller 3 side. A friction lining 28 facing the inner surface of the side cover 5 is provided on the web 25a. The clutch piston 25 has a hub 25c integrally bent at the inner peripheral end thereof slidably supported on the outer peripheral surface of the hub 3h of the turbine impeller 3, and the friction lining 28 is provided on the inner surface of the side cover 5. It can be moved in the axial direction between a connection position where it is pressed into contact with a non-connection position and a non-connection position that is separated from its inner wall. The sliding surface of the hub 25c of the clutch piston 25 with the hub 3h of the turbine impeller 3 is subjected to a surface hardening treatment such as nitriding.
[0027]
As shown in FIGS. 1 and 2, the clutch chamber 22 is provided with a torque damper D for buffer-connecting the clutch piston 25 and the turbine impeller 3. The torque damper D is formed by bending the outer peripheral end of the clutch piston 25 and extends toward the turbine impeller 3. The cylindrical rim 25 b defines an annular spring receiving groove 31 in cooperation with the rim 25 b. An annular spring holding member 30 integrally having a plurality of holding walls 30a, 30a, and a plurality of coiled damper springs 32A, 32A,... 32B, 32B. , 32B, 32B... Are provided with a wear-resistant annular protective plate 29 covering at least the outer peripheral surface of the damper springs 32A, 32A. The plurality of rivets 35 are fixed to the clutch piston 25 in an overlapping manner. The damper spring 32A is formed of a relatively thin wire and has a relatively low spring constant, and the damper spring 32B is formed of a relatively thick wire and has a relatively high spring constant. Are arranged alternately in the circumferential direction.
[0028]
In the above, the clutch piston 25 is made of a thick steel plate, and the spring holding member 30 is made of a steel plate thinner than the clutch piston 25. The protection plate 29 is made of an extremely thin steel plate, and is provided with wear resistance by a surface hardening treatment such as nitriding.
[0029]
The holding walls 30a of the spring holding member 30 are located on the opposite side of the damper springs 32A, 32A,... 32B, 32B. Is formed in a circular arc shape extending radially outward along the side surface and covering substantially half the circumference.
[0030]
In the illustrated example, the protection plate 29 is formed in a U-shaped cross section so as to be fitted to the side surface of the damper springs 32A, 32A,.
[0031]
A plurality of first transmission claws 33, 33... Inserted between the adjacent damper springs 32A, 32B are integrally formed on the spring holding member 30, and each of the first transmission claws 33, 33. A plurality of second transmission claws 34A, 34A,... 34B, 34B,... Inserted between the springs 32A, 32B are welded to the outer peripheral surface of the turbine impeller 3. At this time, in the set state, the damper springs 32A, 32B are contracted between the adjacent first transmission claws 33, 33 with a predetermined set load. Further, some of the second transmission claws 34A are in contact with the damper spring 32A having a low spring constant, but are arranged so as to be separated from the damper spring 32B having a high spring constant by a predetermined distance. On the contrary, it is arranged so as to be in contact with the damper spring 32B having a high spring constant, but to be separated from the damper spring 32A having a low spring constant by a predetermined distance.
[0032]
The plurality of holding walls 30a, 30a... Are arranged at a central portion between adjacent second transmission claws 34A, 34B with half the number of second transmission claws 34A, 34A. One end 30b along the rotation direction of 30a contacts the second transmission claw 34A when the engine is accelerated and a torque equal to or greater than a predetermined value is applied between the clutch piston 25 and the turbine impeller 3, and the damper springs 32A, 32A. , 32B, 32B, and the other end 30b 'along the rotation direction of each holding wall 30a is provided between the clutch piston 25 and the turbine impeller 3 when the engine is decelerated. When a torque equal to or greater than the value is applied, the stopper portion contacts the second transmission claw 34B to limit the compressive deformation of the damper springs 32A, 32A,. Is (see Fig. 3).
[0033]
Referring again to FIG. 1, a first oil passage 40 communicating with the outer chamber 22 b of the clutch chamber 22 via the lateral hole 39 and the thrust needle bearing 36 is provided at the center of the output shaft 10. Further, a second oil passage 41 is defined between the accessory drive shaft 20 and the stator shaft 12 and communicates with the inner peripheral portion of the circulation circuit 6 via the thrust needle bearings 37 and 37 'and the freewheel 11. The first oil passage 40 and the second oil passage 41 are alternately connected to the discharge side of the oil pump 21 and the oil reservoir 43 by a lock-up control valve 42.
[0034]
Next, the operation of this embodiment will be described.
[0035]
When the engine is idling or operating at an extremely low speed, the lock-up control valve 42 connects the first oil passage 40 to the discharge side of the oil pump 21 and connects the second oil passage 41 to the oil reservoir 43, as shown in FIG. Is controlled by an electronic control unit (not shown). Therefore, when the output torque of the crankshaft 1 of the engine is transmitted to the drive plate 8, the side cover 5, and the pump impeller 2, which is driven to rotate and the oil pump 21 is further driven, the discharge operation of the oil pump 21 is started. Oil flows into the circulation circuit 6 from the lock-up control valve 42 through the first oil passage 40, the lateral hole 39, the thrust needle bearing 36, the outer chamber 22b and the inner chamber 22a of the clutch chamber 22 in this order, and fills the circuit 6. Thereafter, the oil is transferred to the second oil passage 41 through the thrust needle bearings 37 and 37 'and the freewheel 11 in order, and is returned from the lock-up control valve 42 to the oil reservoir 43.
[0036]
Thus, in the clutch chamber 22, the outer chamber 22b becomes higher in pressure than the inner chamber 22a due to the flow of the working oil as described above, and the pressure difference causes the clutch piston 25 to move away from the inner wall of the side cover 5. Since the lock-up clutch L is depressed, the lock-up clutch L is in the disconnected state, and the relative rotation of the pump impeller 2 and the turbine impeller 3 is allowed. Therefore, when the pump impeller 2 is rotationally driven from the crankshaft 1, the working oil filling the circulation circuit 5 circulates in the circulation circuit 5 as shown by the arrow, thereby reducing the rotational torque of the pump impeller 2 to the turbine blade. The output is transmitted to the vehicle 3 and the output shaft 10 is driven.
[0037]
At this time, if a torque amplifying action occurs between the pump impeller 2 and the turbine impeller 3, a corresponding reaction force is applied to the stator impeller 4, and the stator impeller 4 is locked by the locking action of the freewheel 11. Fixed.
[0038]
When the torque amplifying operation is completed, the stator impeller 4 rotates in the same direction together with the pump impeller 2 and the turbine impeller 3 while idling the freewheel 11 due to the reversal of the torque direction applied thereto.
[0039]
When the torque converter T enters such a coupling state, the lock-up control valve 42 is switched by the electronic control unit. As a result, the operating oil discharged from the oil pump 21 flows into the circulation circuit 6 from the lock-up control valve 42 through the second oil passage 41 and fills the circuit 6, and the clutch chamber 22 To the inner chamber 22a, and also fills the inner chamber 22a. On the other hand, since the outer chamber 22b of the clutch chamber 22 is opened to the oil reservoir 43 via the first oil passage 40 and the lock-up control valve 42, in the clutch chamber 22, the inner chamber 22a is larger than the outer chamber 22b. When the pressure becomes high, the clutch piston 25 is pressed against the side cover 5 by the pressure difference, and the friction lining 28 is pressed against the inner wall of the side cover 5, and the lock-up clutch L is brought into the connected state. Then, the rotational torque transmitted from the crankshaft 1 to the pump impeller 2 is transmitted from the side cover 5 to the clutch piston 25, the plurality of first transmission claws 33, 33,..., The damper springs 32A, 32A,. Since the transmission is mechanically transmitted to the turbine impeller 3 via the second transmission claws 34A, 34A,..., 34B, 34B, the pump impeller 2 and the turbine impeller 3 are directly connected to each other. The output torque can be efficiently transmitted to the output shaft 10, and the fuel consumption can be reduced. At this time, if a torque fluctuation occurs between the pump impeller 2 and the turbine impeller 3, regardless of the acceleration or deceleration of the engine, the damper spring 32A having a low spring constant firstly causes the first transmission claw 33 and the second transmission claw 34A. When the compression amount exceeds a predetermined value, the damper spring 32B having a high spring constant is compressed between the first transmission claw 30 and the second transmission claw 34B. By absorbing the torque shock stepwise, even a large torque shock with a relatively small angular displacement between the pump impeller 2 and the turbine impeller 3 can be effectively absorbed.
[0040]
When the torque exceeds a predetermined value, when the engine is accelerated, as shown in FIG. 3, the second transmission claw 34A abuts against one stopper portion 30b of the holding wall 30a of the spring holding member 30, thereby causing the damper to move. The compression deformation of the springs 32A, 32A... 32B, 32B... Is limited to a constant value. , 32A...; 32B, 32B. Thus, the damper springs 32A, 32A ...; 32B, 32B ... are protected from overload regardless of the acceleration or deceleration of the engine.
[0041]
The damper springs 32A, 32A ...; 32B, 32B ... are defined by a rim on the outer periphery of the clutch piston 25 and a plurality of holding walls 30a, 30a ... of the annular spring holding member 30 fixed to the clutch piston 25. , 32B, 32B,... Are restricted by the rim 25b, so that the damper springs 32A, 32A,. Are regulated by the holding walls 30a. Therefore, the large centrifugal force generated in the damper springs 32A, 32A,...; 32B, 32B,... During transmission can be firmly supported by the thick rim 25b having a relatively high rigidity. Since it is formed into a cylindrical shape at the outer peripheral end of the clutch piston 25, the molding is easy and can contribute to cost reduction. Since the damper springs 32A, 32A... 32B, 32B... Move toward the turbine impeller 3 side, no large force is required, and the holding walls 30a, 30a. Can be made of a relatively thin steel plate, which can contribute to cost reduction while suppressing weight increase. In addition, the holding wall 30a also serves as a stopper member for limiting the amount of compression of the damper springs 32A, 32A ...; 32B, 32B ... in cooperation with the second transmission claws 34A, 34B. Becomes unnecessary, and the cost can also be reduced.
[0042]
, 32B, 32B, and the rim 25b of the clutch piston 25, a wear-resistant protective plate 29 is interposed therebetween, so that the damper springs 32A, 32A,; 32B, 32B. Can be prevented from abrasion of the rim 25b by avoiding the friction between the damper springs 32A, 32A ,; 32B, 32B and the rim 25b, so that the clutch piston made of steel plate can be prevented. The durability can be improved without subjecting the rim 25 and the rim 25b to a hardening treatment such as nitriding. On the other hand, since the protective plate 29 is a relatively small part, a large amount of the protective plate 29 can be subjected to a surface hardening treatment at once, so that the cost increase by using the wear-resistant protective plate 29 can be compared. It can be kept to a very low level.
[0043]
Moreover, since the protection plate 29 has a U-shaped cross section so that the side surface of the half circumference of the clutch piston 25 side of the damper springs 32A, 32A,. , 32B... In the spring accommodating groove 31 to prevent the generation of vibration noise, and to avoid friction between the damper springs 32A, 32A,. , Can also contribute to the prevention of wear of the clutch piston 25.
[0044]
Further, according to the present invention, the spring holding member 30 and the protection plate 29 are fixed to the clutch piston 25 by rivets 35, 35... Can be fixed to the clutch piston 25 all at once, and an increase in cost due to the fixing of the protection plate 29 can be avoided.
[0045]
FIG. 4 shows a modification of the hub 25c of the clutch piston 25.
[0046]
In this case, the hub 25c is formed by subjecting a ring member separate from the clutch piston 25 to a surface hardening treatment such as nitriding in advance, and is welded to the inner peripheral edge of the clutch piston 25. According to this modification, since the surface hardening process is performed only on the small component hub 25c, a large-scale processing facility is not required, and the surface hardening process can be performed on a large number of hubs 25c at once. Cost can be reduced.
[0047]
The present invention is not limited to the above embodiment, and various design changes can be made without departing from the gist of the present invention. For example, the present invention can be applied to a fluid coupling having no stator impeller. Also, the contact surface of the spring holding member 30 with the damper springs 32A, 32A... 32B, 32B.
[0048]
【The invention's effect】
As described above, according to the first aspect of the present invention, a plurality of damper springs are annularly arranged and accommodated in an annular spring accommodating groove formed in a clutch piston of a lock-up clutch. A plurality of first transmission claws inserted into the clutch piston, and a plurality of second transmission claws inserted between adjacent damper springs together with the first transmission pawl on the turbine impeller. , A cylindrical rim bent at the outer peripheral end of the clutch piston and extending toward the turbine impeller, and an annular spring fixed to the clutch piston in cooperation with the rim to define an annular spring receiving groove. A holding member, and a plurality of coiled damper springs housed in the spring housing grooves and arranged in a ring shape; When a torque equal to or more than a predetermined value is applied between the first transmission claw, the clutch piston and the turbine impeller to the pulling holding member, a stopper is formed to abut on the second transmission claw to limit the deformation of the damper spring. As a result, the large centrifugal force generated in the damper spring during power transmission can be firmly supported by the thick and relatively rigid rim, and the rim is formed into a cylindrical shape on the outer peripheral end of the clutch piston. Therefore, the molding is easy. Since the spring holding member that regulates the movement of the damper spring toward the turbine impeller does not require a large holding force, it can be formed of a relatively thin steel plate. In addition, since the deformation of the damper spring is limited by the cooperation of the stopper portion and the second transmission claw, the damper spring can be protected from overload, and as a result, the torque damper is highly durable, easy to manufacture and lightweight. Can be provided at low cost.
[0049]
According to the second feature of the present invention, in addition to the first feature, the spring holding member is provided along a side surface of the damper spring opposite to the clutch piston from an inner diameter portion of the damper spring. A plurality of arc-shaped holding walls extending outward in the radial direction and substantially covering the side surfaces by substantially a half circumference are integrally formed, and the end of each holding wall in the rotation direction is the stopper portion. Direction movement can be reliably restricted, and this holding wall also works as a stopper member for limiting the amount of compression of the damper spring in cooperation with the second transmission claw, so that a dedicated stopper member is not required. Thus, the cost can be reduced.
[0050]
According to the third aspect of the present invention, in addition to the first or second aspect, a wear-resistant annular protective plate for covering the outer peripheral surface of the damper spring is fixed to the clutch piston. When the spring expands and contracts due to the centrifugal force, the friction between the damper spring and the rim can be avoided to prevent the rim from being worn. Improvement can be achieved.
[0051]
According to the fourth aspect of the present invention, in addition to the third aspect, the inner peripheral ends of the spring holding member and the protection plate are both fixed to the clutch piston by rivets and fixed. The holding member and the protection plate can be fixed to the clutch piston at a stroke, and the cost increase due to the fixing of the protection plate can be avoided.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional side view of a torque converter with a torque damper according to an embodiment of the present invention.
FIG. 2 is a sectional view taken along line 2-2 of FIG.
FIG. 3 is a diagram corresponding to FIG. 2 for explaining the operation of the torque damper.
FIG. 4 is a sectional view showing a modified example of the hub of the clutch piston of FIG. 1;
[Explanation of symbols]
D: Torque damper
L: Lock-up clutch
T: fluid transmission device (torque converter)
3 ... Turbine impeller
25 ... Clutch piston
29..Protection plate
30 ..... Spring holding member
30a ··· Holding wall
30b, 34b '... stopper part
31 .. Spring receiving groove
32A, 32B ... damper spring
33 ・ ・ ・ ・ ・ ・ ・ First transmission claw
34A, 34B ······· Second transmission claw
35 ... Rivets

Claims (4)

A plurality of damper springs (32A, 32B) are annularly arranged and accommodated in an annular spring accommodating groove (31) formed in a clutch piston (25) of the lock-up clutch (L), and an adjacent damper spring (32A) is accommodated. , 32B) provided on the clutch piston (25), and a plurality of first transmission claws (33) inserted between the adjacent damper springs (32A, 32B) together with the first transmission claws (33). In the torque damper of the fluid transmission device in which the second transmission claws (34A, 34B) are provided on the turbine impeller (3),
A cylindrical rim (25b) bent at the outer peripheral end of the clutch piston (25) and extending toward the turbine impeller (3); and an annular spring receiving groove (31) cooperating with the rim (25b). An annular spring holding member (30) fixed to the clutch piston (25) and a plurality of damper springs (32A, 32B) accommodated in the spring accommodating groove (31) and arranged in an annular shape. The second transmission pawl when a torque equal to or more than a predetermined value is applied to the spring holding member (30) between the first transmission pawl (33) and the clutch piston (25) and the turbine impeller (3). A fluid transmission device characterized by forming stopper portions (30b, 30b ') for restricting deformation of the damper springs (32A, 32B) in contact with (34A, 34B). Torque damper of. The torque damper for a fluid transmission according to claim 1,
The spring holding member (30) extends radially outward from the inner diameter of the damper spring (32A, 32B) along the side surface of the damper spring (32A, 32B) opposite to the clutch piston (25). And a plurality of arc-shaped holding walls (30a) extending substantially to cover the side surface substantially half way, and the rotation direction ends of the holding walls (30a) are defined as the stopper portions (30b, 30b '). Characterized by a torque damper for a fluid transmission. The torque damper for a fluid transmission according to claim 1 or 2,
A torque damper for a fluid transmission, wherein a wear-resistant annular protective plate (29) for covering an outer peripheral surface of the damper springs (32A, 32B) is fixed to the clutch piston (25). The torque damper for a fluid transmission according to claim 3,
A torque damper for a fluid transmission device, wherein inner ends of the spring holding member (30) and the protection plate (29) are both overlapped with the clutch piston (25) and fixed by rivets (35).

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