JP4458951B2 - Fluid transmission device - Google Patents

Description

  The present invention relates to a fluid transmission device including a torque converter and a fluid coupling used in automobiles and the like, and in particular, a pump impeller and a circuit for circulating a working oil between the pump impeller and the pump impeller. A transmission cover defining a clutch chamber that communicates with the circulation circuit between the turbine impeller that is connected to the outer periphery of the pump impeller and communicates with the circulation circuit, and is disposed in the clutch chamber. A drive plate connected to the engine crankshaft, and a hub of the turbine impeller (hereinafter referred to as a turbine hub) having an output shaft coaxial with the crankshaft. The transmission cover hub (hereinafter referred to as the cover hub) is arranged coaxially with the output shaft, and the lockup clutch is connected to an annular drive formed on the outer peripheral portion of the inner wall of the transmission cover. A friction surface, a hub (hereinafter referred to as a piston hub) supported so as to be rotatable and axially movable on the hub of the turbine impeller, and an annular driven friction surface that can be engaged with and disengaged from the drive friction surface A clutch piston having an annular wall portion formed on the clutch piston, and a torque damper having a plurality of damper springs arranged annularly adjacent to the annular wall portion of the clutch piston and bufferingly coupling the clutch piston and the turbine impeller It is related with improvement of a fluid power transmission device constituted by.

Such a fluid transmission device is already known as disclosed in, for example, Patent Document 1 below.
JP 2003-106403 A

  In such a conventional fluid transmission device, as disclosed in Patent Document 1, a plurality of annular step portions are formed concentrically on the transmission cover to increase the bending rigidity of the member. However, when the transmission cover is formed with a large diameter in order to increase the capacities of the lock-up clutch and the torque damper, if the transmission cover exceeds a certain limit, the transmission cover will not be extended due to the expansion of the plurality of annular steps due to the high internal hydraulic pressure. It has been found that there is a tendency to bulge and deform in the axial direction.

  The present invention has been made in view of such circumstances, and prevents the bulging deformation in the axial direction of the transmission cover even when the transmission cover has a larger diameter, and can be coupled to the engine in a compact manner. An object is to provide a fluid transmission device.

In order to achieve the above object, the present invention provides a pump impeller, a turbine impeller opposed to the pump impeller and defining a working oil circulation circuit therebetween, and an outer peripheral portion of the pump impeller. And a transmission cover defining a clutch chamber communicating with the circulation circuit between the rear surface of the turbine impeller and a lock-up clutch disposed in the clutch chamber. The drive plate connected to the crankshaft of the engine is connected, the hub of the turbine impeller (hereinafter referred to as the turbine hub) is connected to the output shaft coaxial with the crankshaft, and the transmission cover hub (hereinafter referred to as the cover hub). .) Is arranged coaxially with the output shaft, and the lock-up clutch is rotated and moved in the axial direction on the annular driving friction surface formed on the outer peripheral portion of the inner wall of the transmission cover and the hub of the turbine impeller. A clutch piston having a hub (hereinafter referred to as a piston hub) that is supported by the performance, an annular side wall portion having an annular driven friction surface that can be engaged with and disengaged from the driving friction surface on the inner surface, and the clutch piston A fluid transmission device comprising a plurality of damper springs arranged annularly adjacent to the annular side wall portion of the clutch damper and a torque damper for buffering connection between the turbine impeller and the transmission cover. A conical side wall which is close to the turbine impeller is provided from the annular side wall to the cover hub, and is connected to the outer side surface of the conical side wall. defining a by Lien conical recess, and disposed along parallel to the drive plate to the annular side wall portion and a conical side wall portion of the transmission cover, said drive plate The first bolt coupled to the end face of the rank shaft is received in the conical recess together with the end of the crankshaft, and the starting ring gear is welded to the axially intermediate portion of the outer peripheral surface of the peripheral wall of the transmission cover, A flange is formed on the outer peripheral portion of the drive plate so as to wrap around the outer peripheral surface of the ring gear and wrap around the outer peripheral surface of the transmission cover. The flange is coupled to the ring gear by a second bolt. Is arranged inward in the axial direction from the outer surface of the drive plate .

  According to the present invention, in addition to the first feature, the clutch piston is connected to the piston hub between the annular side wall portion on which the driven friction surface is formed and the piston hub. A second feature is that a conical side wall portion substantially the same as the portion is provided.

Furthermore, in addition to the first or second feature, the present invention sets the diameter of the annular arrangement center circle of the plurality of damper springs arranged in an annular shape to be larger than the outer diameter of the turbine impeller , and the plurality of dampers. A third feature is that the diameter of the inner circumference of the spring is set smaller than the outer diameter of the turbine impeller .

The fluid transmission device corresponds to a torque converter T in an embodiment of the present invention to be described later, and the annular side wall portion of the transmission cover and the annular side wall portion of the clutch piston are the same as those of the transmission cover 5 in the embodiment. It corresponds to the outer peripheral annular side wall portion 5b and the outer peripheral annular side wall portion 25b of the clutch piston 25, the driven friction surface corresponds to the friction lining 36 in the embodiment, and the first bolt and the second bolt are the same in the embodiment. These correspond to the bolt 9 and the bolt 9 'in the middle embodiment, respectively .

  According to the first feature of the present invention, there is provided a conical side wall portion that connects between the annular side wall portion that forms the driving friction surface and the cover hub. Even when the transmission cover is formed to have a large diameter to accommodate the lock-up clutch and the torque damper, its pressure resistance is high, and the axial deformation of the transmission cover due to the internal high hydraulic pressure can be suppressed as much as possible. Concentration can be effectively avoided.

In addition, the conical recess defined by the outer side surface of the conical side wall portion accommodates the head of the first bolt that connects the drive plate to the end surface of the crankshaft, so that the first bolt is relatively tall. While the head is used to secure a large tightening force on the crankshaft of the drive plate, the axial dimension of the fluid transmission and engine assembly can be shortened, and the assembly can be made compact. Can contribute.

  According to a second aspect of the present invention, the clutch piston is substantially the same as the conical side wall portion of the transmission cover that connects the annular side wall portion having the annular driven friction surface and the piston hub. Since the conical side wall is provided, the transmission cover can be disposed as close as possible to the turbine impeller together with the clutch piston, and the torque converter can be made compact.

  Further, according to the third feature of the present invention, a large-capacity torque damper having an annular arrangement center circle of a plurality of damper springs arranged in an annular arrangement larger than the outer diameter of the turbine impeller is provided inside the outer periphery of the transmission cover. It can be installed, effectively absorbing the connection shock of the lock-up clutch, and greatly contributing to the improvement of the ride comfort of the vehicle.

  Embodiments of the present invention will be described below on the basis of preferred embodiments of the present invention shown in the accompanying drawings.

  FIG. 1 is a longitudinal sectional side view of the upper half of an automotive torque converter according to an embodiment of the present invention (cross-sectional view taken along line 1-1 in FIG. 2), FIG. 2 is a cross-sectional view taken along line 2-2 in FIG. FIG.

  First, in FIG. 1, a torque converter T for an automobile includes a pump impeller 2, a turbine impeller 3 opposed to the pump impeller 2, and a stator impeller 4 disposed between the inner peripheral portions thereof. A circulation circuit 6 for power transmission by hydraulic oil is defined between the cars 2, 3 and 4. The pump impeller 2 is provided with a transmission cover 5 that covers the outer surface of the turbine impeller 3.

  As shown in FIGS. 1 and 3, the transmission cover 5 has a cylindrical shape integrally connected by welding to a shell enlarged portion 2 a extending radially outward from the outer peripheral end of the shell of the pump impeller 2. The peripheral wall portion 5a, the outer peripheral annular side wall portion 5b bent perpendicularly inward in the radial direction from the outer end of the peripheral wall portion 5a, and the turbine impeller 3 as it goes from the inner peripheral end of the outer peripheral annular side wall portion 5b toward the center side. A conical side wall portion 5c close to the side, an inner peripheral annular side wall portion 5d extending inward in the radial direction from the inner peripheral end of the conical side wall portion 5c in parallel with the outer peripheral annular side wall portion 5b, and the inner peripheral annular side wall portion The conical side wall portion 5c does not have an annular step portion at the middle portion. The cap-shaped cover hub 5h is connected to the inner peripheral end of 5d by welding. The cover hub 5h is arranged so that the closed tip end protrudes outward in the axial direction from the outer surface of the outer peripheral annular side wall 5b.

  The transmission cover 5 is formed by pressing a steel plate having the same thickness as the shell of the pump impeller 2 from the peripheral wall portion 5a to the inner peripheral annular side wall portion 5d. An annular drive friction surface 35 of a lockup clutch L described later is formed by cutting. A conical recess 5f surrounding the cover hub 5h is defined on the outer surface of the transmission cover 5 by the conical side wall 5c.

Referring again to FIG. 1, a starting ring gear 7 is fitted and welded to the outer peripheral surface of the peripheral wall portion 5 a of the transmission cover 5, and a drive plate connected to the end surface of the crankshaft 1 of the engine by a bolt 9. 8 is fixed with a bolt 9 '. The drive plate 8 is formed so as to be substantially along the outer surface of the transmission cover 5, and in particular, portions of the transmission cover 5 facing the outer peripheral annular side wall portion 5 b and the conical side wall portion 5 c are arranged in parallel with them. The end of the crankshaft 1 and the head of the bolt 9 are received in the recess 5f on the outer surface of the transmission cover 5. In particular, the head of the bolt 9 is disposed at the deepest portion of the recess 5f.

The ring gear 7 is disposed in the axially intermediate portion of the outer peripheral surface of the peripheral wall portion 5a of the transmission cover 5, and correspondingly, the ring gear 7 wraps around the outer peripheral portion of the drive plate 8 toward the peripheral wall portion 5a of the transmission cover 5 and A flange 8 a overlapping the outer side surface is formed, and this flange 8 a is fixed to the ring gear 7 by a bolt 9 ′. The head of the bolt 9 ′ is disposed inward in the axial direction from the outer surface of the drive plate 8.

  A bag-like positioning hole 1a is provided on the end surface of the crankshaft 1, and the cover hub 5h is fitted into the positioning hole 1a.

  A thrust needle bearing 26 is interposed between the hub 3 h (hereinafter referred to as the turbine hub 3 h) of the turbine impeller 3 and the transmission cover 5.

  An output shaft 10 is disposed coaxially with the crankshaft 1 at the center of the torque converter T. The output shaft 10 is a main shaft of a multi-stage transmission (not shown), and a turbine hub 3h is spline-fitted thereto. The end of the output shaft 10 is rotatably supported by the cover hub 5h via the bearing bush 23.

  A hollow cylindrical stator shaft 12 for supporting a hub 4h of the stator impeller 4 (hereinafter referred to as a stator hub 4h) via a free wheel 11 is disposed on the outer periphery of the output shaft 10, and these output shaft 10 and stator shaft Between 12, a bearing bush 13 that allows relative rotation thereof is interposed. The outer end portion of the stator shaft 12 is supported by the transmission case 14 so as not to rotate.

  The free wheel 11 includes an outer race 15 that is coupled to the inner peripheral surface of the stator hub 4h by press-fitting, an inner race 16 that is spline-coupled to the outer periphery of the stator shaft 12, and an annular arrangement interposed between the races 15 and 16. It consists of sprags 17, 17. The stator impeller 4 is made of a light alloy such as an Al alloy, and the outer race 15 press-fitted into the inner peripheral surface of the stator hub 4h is made of steel. An end wall 27 that supports one end surface of the outer race 15 and faces one end surface of the sprags 17, 17... Is formed integrally with the stator hub 4 h, and is formed between the end wall portion 27 and the pump hub 2 h of the pump impeller 2. A thrust needle bearing 29 is interposed.

  In the stator hub 4h, a pressing plate 28 that is in contact with the outer end surface of the outer race 15 and is opposed to the other end surface of the sprags 17, 17,... Is disposed. 29 'is interposed.

  An auxiliary machine drive shaft 20 coupled 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 that supplies hydraulic oil to the torque converter T is driven by the auxiliary machine drive shaft 20. It has come to be.

  The turbine impeller 3 and the transmission cover 5 are defined by a clutch chamber 22 communicating with the circulation circuit 6 at the outer periphery, and the clutch chamber 22 has a lock-up that allows direct connection between the turbine impeller 3 and the transmission cover 5. A clutch L is provided. That is, the clutch piston 25 which forms the main body of the lockup 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 transmission cover 5 side. .

  The clutch piston 25 includes a cylindrical rim portion 25a that is close to the inner peripheral surface of the peripheral wall portion 5a of the transmission cover 5, an outer peripheral annular side wall portion 25b that is bent at a right angle radially inward from the outer end of the rim portion 25a, , A conical side wall portion 25c close to the turbine impeller 3 from the inner peripheral end of the outer peripheral annular side wall portion 25b toward the center, and an outer peripheral annular side wall radially inward from the inner peripheral end of the conical side wall portion 25c. The inner peripheral annular side wall portion 25d extending in parallel with the portion 25b and a piston hub 25h welded to the inner peripheral end of the inner peripheral annular side wall portion 25d are provided on the outer surface of the turbine impeller 3. The outer peripheral annular side wall portion 25b, the conical side wall portion 25c and the inner peripheral annular side wall portion 25d of the clutch piston 25 are arranged as close to each other as possible. Jo side wall 5c and the inner peripheral annular side wall portion 5d is disposed to face in close proximity, respectively.

  An annular friction lining 36 facing the drive friction surface 35 is formed on the outer surface of the outer peripheral annular side wall 25b of the clutch piston 25 by adhesion. The clutch piston 25 attaches the friction lining 36 to the drive friction surface 35. The piston hub 25h is slidably supported on the outer peripheral surface of the turbine hub 3h so that the piston hub 25h can be moved between a connection position where the piston hub 25h is brought into pressure contact with and a non-connection position separated from the driving friction surface 35.

  As shown in FIGS. 1 and 2, the clutch chamber 22 is provided with a known torque damper D for bufferingly connecting the clutch piston 25 and the turbine impeller 3. The torque damper D includes a rim portion 25a of the clutch piston 25, a plurality of damper springs 32A, 32A,... 32B, 32B,. A plurality of arc-shaped spring holding members 30, 30 that are arranged in an annular shape to hold the inner peripheral sides of the springs 32A, 32A,... 32B, 32B, and are fixed to the clutch piston 25 by a pair of rivets 38, 38, respectively. … And. A flat portion 25ca for fixing each spring holding member 30 with rivets 38, 38 is partially formed on the outer peripheral portion of the conical side wall portion 25c of the clutch piston 25.

  The damper spring 32A is molded with a relatively thin wire rod to give a relatively low spring constant, and the damper spring 32B is molded with a relatively thick wire rod to give a relatively high spring constant. Alternatingly arranged in the circumferential direction.

  The first transmission pawls 33, 33... Inserted between the adjacent damper springs 32A, 32B are integrally formed at opposite ends of the adjacent spring holding members 30, 30, respectively. A plurality of second transmission claws 34A, 34A, 34B, 34B, which are inserted between the adjacent damper springs 32A, 32B together with the claws 33, 33, are welded to the outer peripheral surface of the turbine impeller 3. At that time, in the set state, the damper springs 32A and 32B are contracted between the adjacent first transmission claws 33 and 33 with a predetermined set load. Some of the second transmission claws 34A abut against the damper spring 32A having a low spring constant, but are arranged to be separated from the damper spring 32B having a high spring constant by a predetermined distance. On the other hand, it is in contact with the damper spring 32B having a high spring constant, but is arranged so as to be separated from the damper spring 32A having a low spring constant by a predetermined distance.

And Thus, each portion of the torque converter T is Ri plurality of damper springs 32A, the diameter d2 of the annular array center circle C of 32B is Daito name than the outer diameter d1 of the turbine impeller 3, and a plurality of damper springs 32A, 32B the inner circumference d3 is formed in the small city of so that than the outer diameter d1 of the turbine impeller 3.

  In FIG. 1 again, a first oil passage 40 communicating with the outer chamber 22 b of the clutch chamber 22 through the lateral hole 24 and the thrust needle bearing 26 is provided at the center of the output shaft 10. Further, a second oil passage 41 communicating with the inner peripheral portion of the circulation circuit 6 via the thrust needle bearing 29 is defined between the auxiliary machine drive shaft 20 and the stator shaft 12. The second oil passage 41 is alternately connected to the discharge side of the oil pump 21 and the oil reservoir 43 by a lock-up control valve 42.

  Next, the operation of this embodiment will be described.

  In the engine idling or extremely low speed operation region, the lockup control valve 42 connects the first oil passage 40 to the discharge side of the oil pump 21 and the second oil passage 41 as shown in FIG. It is controlled by an electronic control unit (not shown) so as to be connected to. Therefore, when the output torque of the crankshaft 1 of the engine is transmitted to the drive plate 8, the transmission cover 5, and the pump impeller 2 to rotate and drive the oil pump 21, the discharge operation of the oil pump 21 is performed. The oil sequentially flows from the lock-up control valve 42 into the circulation circuit 6 through the first oil passage 40, the lateral hole 24 and the thrust needle bearing 26, the outer chamber 22b of the clutch chamber 22, and the inner chamber 22a to fill the circuit 6. Thereafter, the oil is transferred to the second oil passage 41 through the thrust needle bearing 29 and returned to the oil reservoir 43 from the lockup control valve 42.

  Thus, in the clutch chamber 22, the outer chamber 22b has a higher pressure than the inner chamber 22a due to the flow of the working oil as described above, and the clutch piston 25 is separated from the drive friction surface 35 of the transmission cover 5 due to the pressure difference. The lockup clutch L is in a disconnected state because it is pressed in the direction, 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 that fills the circulation circuit 5 circulates in the circulation circuit 5 as indicated by the arrows, thereby reducing the rotational torque of the pump impeller 3 to the turbine blade. This is transmitted to the car 4 to drive the output shaft 10.

  At this time, if a torque amplifying action is generated between the pump impeller 2 and the turbine impeller 3, the accompanying reaction force is borne by the stator impeller 4, and the stator impeller 4 is caused by the locking action of the freewheel 11. That is, the sprags 17, 17... Are connected and fixed to the stator shaft 12 by being locked between the races 15 and 16 so as to prevent relative rotation of the outer race 15 and the inner race 16.

  When the torque amplifying operation is finished, the stator impeller 4 is rotated by the reversal of the torque direction received by the stator impeller 4, that is, the sprags 17, 17... Allow the relative rotation of the races 15, 16. The pump impeller 2 and the turbine impeller 3 rotate in the same direction.

  When the torque converter T enters such a coupling state, the lockup control valve 42 is switched by the electronic control unit. As a result, the discharge hydraulic oil of the oil pump 21 flows into the circulation circuit 6 from the lockup control valve 42 through the second oil passage 41 and fills the circuit 6, contrary to the previous time, and then the clutch chamber 22. The inner chamber 22a is filled to fill the inner chamber 22a. On the other hand, since the outer chamber 22b of the clutch chamber 22 is opened to the oil sump 43 via the first oil passage 40 and the lockup control valve 42, in the clutch chamber 22, the inner chamber 22a is more than the outer chamber 22b. Due to the pressure difference, the clutch piston 25 is pressed to the transmission cover 5 side, the friction lining 36 is brought into pressure contact with the drive friction surface 35 of the transmission cover 5, and the lockup clutch L is connected. Then, since the rotational torque transmitted from the crankshaft 1 to the pump impeller 2 is mechanically transmitted from the transmission cover 5 to the turbine impeller 3 via the clutch piston 25 and the torque damper D, the pump impeller 2 and The turbine impeller 4 is directly connected, and the output torque of the crankshaft 1 can be efficiently transmitted to the output shaft 10, thereby reducing fuel consumption. At this time, if torque fluctuation occurs between the pump impeller 2 and the turbine impeller 3, the damper spring 32A having a low spring constant is first connected to the first transmission claw 33 and the second transmission claw 34A regardless of the acceleration and deceleration of the engine. 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 in a stepwise manner, even a large torque shock can be effectively absorbed with a relatively small angular displacement between the pump impeller 2 and the turbine impeller 3.

  By the way, in such a torque converter T, the transmission cover 5 is connected to the outer peripheral annular side wall 5b formed with the drive friction surface 35 and the cover hub 5h. When the conical side wall 5c close to the impeller 3 is provided, and there is no annular step between them, the transmission cover 5 is formed with a large diameter so as to accommodate the large-capacity lockup clutch L and the torque damper D. However, the pressure resistance is high, the axial deformation of the transmission cover 5 due to the internal high hydraulic pressure can be suppressed as much as possible, and stress concentration can be effectively avoided.

  Moreover, not only the end of the crankshaft 1 is received in the conical recess 5f defined by the outer surface of the conical side wall 5c, but in particular, the crankshaft 1 is located at the deepest portion of the recess 5f. Since the head of the bolt 9 that couples the drive plate 8 is housed on the end face of the bolt 9, a relatively high head of the bolt 9 is used to secure a large tightening force of the drive plate 8 to the crankshaft 1. The axial dimensions of the torque converter T and the engine assembly can be shortened, which can contribute to the compactness of the assembly.

  The cap-shaped cover hub 5h has a closed tip projecting axially outward from the outer surface of the outer peripheral side wall 5b and is fitted into a bag-like positioning hole 1a at the center of the end surface of the crankshaft 1. Therefore, the fitting depth between the cover hub 5h and the positioning hole 1a can be sufficiently secured in combination with the protrusion of the end of the crankshaft 1 into the recess 5f.

  The clutch piston 25 of the lockup clutch L is connected to the outer peripheral annular side wall 25b formed with the annular friction lining 36 and the piston hub 25h. The cone angle is substantially the same as that of the conical side wall 5c of the transmission cover 5. Since the same conical side wall portion 25c is provided, the transmission cover 5 and the clutch piston 25 can be arranged as close as possible to the turbine impeller 3, and the torque converter T can be made compact.

  Further, by providing the conical side wall 5c in the transmission cover 5, a relatively large annular space that is not interfered with the turbine impeller 3 can be formed inside the outer periphery of the transmission cover 5, and this space is utilized. Thus, the friction engagement portion of the lockup clutch L having a relatively large capacity and the torque damper D can be provided. In particular, it is possible to dispose a large-capacity torque damper D in which the diameter d2 of the annular arrangement center circle C of the plurality of damper springs 32A, 32B in the annular arrangement is larger than the outer diameter d1 of the turbine impeller 3, and the lockup clutch By effectively absorbing the connection shock of L, it can greatly contribute to the improvement of the ride comfort of the automobile.

  The present invention is not limited to the above embodiment, and various design changes can be made without departing from the scope of the invention.

The upper half longitudinal cross-sectional side view (torque line sectional view of FIG. 2) of the torque converter for motor vehicles concerning the Example of this invention. FIG. 2 is a sectional view taken along line 2-2 in FIG. 1. FIG. 3 is a sectional view taken along line 3-3 in FIG. 1.

C ··· Turbine impeller outer diameter D ··· Torque damper L ··· Lockup clutch T ··· Fluid transmission device (torque converter)
DESCRIPTION OF SYMBOLS 1 ... Engine crankshaft 2 ... Pump impeller 3 ... Turbine impeller 5 ... Transmission cover 5b ... Annular side wall ( Outer peripheral side wall)
5c: Conical side wall 5f: Recess 5h: Cover hub 6 ... Circulation circuit 8 ... Drive plate
8a: Flange
9 ・ ・ ・ ・ ・ ・ First bolt ( bolt)
9 '... 2nd bolt ( bolt)
10... Output shaft 22... Clutch chamber 25... Clutch piston 25 b...
25c ··· Conical side wall portion 25h ··· Piston hub 32A, 32B ··· Damper spring 35 ··· Driving friction surface 36 ··· Following friction surface (friction lining)

Claims (3)

A pump impeller (2), a turbine impeller (3) that is opposed to the pump impeller (2) and defines a working oil circulation circuit (6) therebetween, and a pump impeller (2) A transmission cover (5) defining a clutch chamber (22) communicating with the circulation circuit (6) between the outer periphery of the turbine impeller (3) and the rear surface of the turbine impeller (3), and the clutch chamber (22 And a drive plate (8) connected to the crankshaft (1) of the engine is connected to the transmission cover (5), and the turbine impeller (3) is connected to the transmission cover (5). An output shaft (10) coaxial with the crankshaft (1) is connected to the turbine hub (3h), a cover hub (5h) of the transmission cover (5) is coaxially arranged with the output shaft (10), and the lock Connect the up clutch (L) to the outer periphery of the inner wall of the transmission cover (5). An annular driving friction surface (35) formed, a piston hub (25h) supported rotatably and axially on the turbine hub (3h) of the turbine impeller (3), and the driving friction surface (35) A clutch piston (25) having an annular side wall portion (25b) having an annular driven friction surface (36) that can be engaged and disengaged with the inner surface, and an annular side wall portion (25b) of the clutch piston (25). Fluid transmission constituted by a torque damper (D) having a plurality of damper springs (32A, 32B) arranged annularly adjacent to each other and bufferingly connecting the clutch piston (25) and the turbine impeller (3). In the device,
The transmission cover (5) connects the annular side wall (5b) formed with the drive friction surface (35) and the cover hub (5h) from the annular side wall (5b) to the cover hub (5h). conical side wall portion proximate the turbine wheel (3) as toward the (5c) and is provided, defining a Lien conical recess (5f) by the outer surface of the conical side wall portion (5c), the drive A plate (8) is arranged along the annular side wall portion (5b) and the conical side wall portion (5c) of the transmission cover (5), and this drive plate (8) is disposed on the end face of the crankshaft (1). The first bolt (9) coupled to the crankshaft (1) is received in the conical recess (5f) together with the end of the crankshaft (1), and the axially intermediate portion of the outer peripheral surface of the peripheral wall (5a) of the transmission cover (5) The starting ring gear (7) is welded to the outer periphery of the drive plate (8), A flange (8a) is formed which wraps around the peripheral wall (5a) side of the transmission cover (5) and overlaps the outer surface of the ring gear (7). The flange (8a) is connected to the ring gear (7) with a second bolt ( 9 '), and the head of the second bolt (9') is disposed axially inward from the outer surface of the drive plate (8) . The fluid transmission device according to claim 1,
The clutch piston (25) has a conical angle connecting the annular side wall portion (25b) formed with the driven friction surface (36) and the piston hub (25h) at a conical angle of the transmission cover (5). A fluid transmission device comprising a conical side wall portion (25c) substantially the same as the shape side wall portion (5c). The fluid transmission device according to claim 1 or 2,
The diameter (d2) of the annular arrangement center circle (C) of the plurality of damper springs (32A, 32B) arranged in an annular shape is set larger than the outer diameter (d1) of the turbine impeller (3), and A fluid transmission device characterized in that the diameter (d3) of the inner circumference of the damper spring (32A, 32B) is set smaller than the outer diameter (d1) of the turbine impeller (3) .

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