JP2008215377A - Fluid coupling - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve a capacity coefficient in a fluid coupling arranged between an engine and a transmission. <P>SOLUTION: This fluid coupling 1 has a front cover 2, an impeller 3 and a turbine 4. A flow passage P formed in the axial direction between a first flow passage forming part 31b of an impeller 31 and a second flow passage forming part 41b of a turbine shell 41, includes a part enlarging in an axial directional dimension toward the inside in the radial direction or a part unchanging in the axial directional dimension. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a fluid coupling, and more particularly, to a fluid coupling provided between an engine and a transmission.

  Conventionally, a torque converter and a fluid coupling are known as a fluid torque transmission device provided between an engine and a transmission. For example, the fluid coupling includes a front cover to which torque is input, an impeller fixed to the front cover, a turbine disposed to face the impeller, and a lockup device that mechanically connects the front cover and the turbine. ,have. The impeller has an annular impeller shell, a plurality of impeller blades fixed to the impeller shell, and an impeller hub provided on the inner peripheral side of the impeller shell. The turbine includes an annular turbine shell, a plurality of turbine blades fixed to the turbine shell, and a turbine hub provided on the inner peripheral side of the turbine shell. A fluid chamber filled with a working fluid is formed by the front cover and the impeller.

In this fluid coupling, the impeller is connected to a crankshaft which is a member on the engine side through a front cover, and the turbine is connected to an input shaft on the transmission side. When the front cover and the impeller rotate, torque is transmitted from the impeller to the turbine via the working fluid (see, for example, Patent Document 1).
JP-A-63-72964

  However, in this type of fluid coupling, the pressure of the working fluid tends to increase around the turbine outlet and the impeller inlet. For this reason, when the impeller blade is present in a high pressure region, the pressure fluctuation of the impeller blade increases, and the capacity coefficient of the fluid coupling decreases.

  An object of the present invention is to improve the capacity coefficient in a fluid coupling.

  The fluid coupling according to the first invention is a device for transmitting torque via a fluid. The fluid coupling includes a front cover to which torque is input, an impeller, and a turbine. The impeller is fixed to the front cover, forms a fluid chamber filled with fluid, and includes an impeller shell and a plurality of impeller blades fixed to the impeller shell. The turbine is disposed opposite to the impeller in the fluid chamber, and includes a turbine shell and a plurality of turbine blades fixed to the turbine shell. The impeller shell includes an annular first fixed portion to which the impeller blade is fixed, an annular first flow path forming portion extending radially inward from an inner peripheral edge of the first fixed portion, and an inner peripheral edge of the first flow path forming portion. An annular first support portion extending radially inward from the first support portion. The turbine shell includes a second fixing portion to which the turbine blade is fixed, and an annular second portion extending radially inward from the inner peripheral edge of the second fixing portion so as to face the first flow path forming portion in the axial direction. A flow path forming portion and an annular second support portion extending radially inward from the inner periphery of the second flow path forming portion. The flow path formed between the axial directions of the first and second flow path forming portions includes a portion where the axial dimension increases as it goes radially inward or a portion where the axial dimension does not change.

  In this fluid coupling, when the front cover and the impeller rotate, the working fluid flows from the outer periphery of the impeller to the outer periphery of the turbine. This working fluid flows radially inward between the turbine blades, and further from the turbine outlet (the inner peripheral portion of the second fixed portion of the turbine shell) to the inlet of the impeller (the inner peripheral portion of the first fixed portion of the impeller shell). Flows in. As a result, the working fluid rotates the turbine, and torque is transmitted from the impeller to the turbine via the working fluid.

  Generally, the area between the turbine outlet and the impeller inlet tends to increase the working fluid pressure. In this fluid coupling, a flow path is formed by the first and second flow path forming portions between the turbine outlet and the impeller inlet in the axial direction. This flow path includes a portion where the axial dimension increases as it goes radially inward or a portion where the axial dimension does not change. For this reason, the axial direction distance from the turbine outlet to the impeller inlet is longer than in the prior art, and the pressure fluctuation of the impeller blade is suppressed. Thereby, the flow of the working fluid from the turbine to the impeller becomes smooth, and the capacity coefficient is improved as compared with the conventional product.

  A fluid coupling according to a second invention is the fluid coupling according to the first invention, wherein the first flow path forming portion has an annular first portion extending radially inward from the inner peripheral edge of the first fixing portion. Yes. The second flow path forming portion has an annular second portion extending radially inward from the inner peripheral edge of the second fixed portion, and a cylindrical portion extending from the inner peripheral edge of the second portion toward the axial impeller shell. ing.

  The fluid coupling according to a third aspect of the present invention is the fluid coupling according to the second aspect of the present invention, wherein the second portion has a curved portion that curves so as to protrude toward the axial front cover.

  A fluid coupling according to a fourth invention is the fluid coupling according to the second or third invention, wherein the maximum distance between the axial directions of the first and second fixing portions is L, and between the axial directions of the first and second portions. When S is the minimum distance, S / L ≧ 0.3 is satisfied.

  A fluid coupling according to a fifth aspect is the fluid coupling according to any one of the first to fourth aspects, wherein the maximum distance between the axial directions of the first and second fixing portions is L, and the maximum distance in the radial direction of the impeller blades When the larger one of the dimension and the maximum dimension in the radial direction of the turbine blade is H, 0.8 ≦ L / H ≦ 1.0 is satisfied.

  A fluid coupling according to a sixth invention is the fluid coupling according to any one of the first to fifth inventions, wherein the maximum distance between the first and second fixing portions in the axial direction is L, and the radius of the impeller blade from the rotation shaft When the larger one of the distance to the outer end in the direction and the distance from the rotating shaft to the outer end in the radial direction of the turbine blade is D, 0.1 ≦ L / D ≦ 0.15 is satisfied.

  A fluid coupling according to a seventh invention is the fluid coupling according to any one of the first to sixth inventions, wherein the maximum distance between the first and second fixing portions in the axial direction is L, and the impeller blade is a shaft between the turbine blade and the shaft. B2 / L ≦ 1.0 is satisfied, where B2 is the larger of the radial dimension of the end portion facing in the direction and the radial dimension of the end portion of the turbine blade facing the impeller blade in the axial direction.

  A fluid coupling according to an eighth aspect of the present invention is the fluid coupling according to any one of the first to seventh aspects, wherein the turbine blade has a tapered portion facing the impeller in the axial direction on the radially outer side. When the angle formed by the taper portion and the plane orthogonal to the rotation axis is θ, 10 ° ≦ θ ≦ 30 ° is satisfied. When the maximum dimension in the radial direction of the taper portion is B1, and the larger one of the maximum dimension in the radial direction of the impeller blade and the maximum dimension in the radial direction of the turbine blade is H, 0.15 ≦ B1 / H ≦ 0.3 Satisfies.

  Since the fluid coupling according to the present invention has the above-described configuration, the capacity coefficient is improved.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. Here, a fluid coupling will be described as an example of the fluid torque transmission device.

<Configuration of fluid coupling>
The structure of the fluid coupling 1 is demonstrated using FIG. 1 and FIG. FIG. 1 is a schematic vertical sectional view of a fluid coupling 1. FIG. 2 is a partial cross-sectional view of the damper mechanism 6 and its periphery. The line OO in FIGS. 1 and 2 is the rotation axis of the fluid coupling 1.

  The fluid coupling 1 is a device for transmitting torque of an engine (not shown) arranged on the left side of FIG. 1 to a transmission (not shown) arranged on the right side of FIG. Specifically, as shown in FIG. 1, the fluid coupling 1 mainly includes a front cover 2 and an impeller 3 as input members, a turbine 4 as an output member, and the front cover 2 and the turbine 4 mechanically. And a lockup device 5 to be coupled.

  The front cover 2 is connected to, for example, a crankshaft on the engine (not shown) side, and torque is input from the engine via the crankshaft. An outer peripheral cylindrical portion 21 extending toward the transmission (not shown) is provided on the outer peripheral portion of the front cover 2.

  The impeller 3 mainly includes an annular impeller shell 31, a plurality of impeller blades 32 fixed to the impeller shell 31, and an impeller hub 33 fixed to the inner peripheral portion of the impeller shell 31. The impeller shell 31 is fixed to the outer peripheral cylindrical portion 21 of the front cover 2. The impeller shell 31 and the front cover 2 form a fluid chamber filled with a working fluid.

  The turbine 4 is disposed to face the impeller 3 in the fluid chamber, and constitutes a torus T together with the impeller 3. The turbine 4 mainly includes an annular turbine shell 41, a plurality of turbine blades 42 fixed to the turbine shell 41, and a turbine hub 43 fixed to the inner peripheral portion of the turbine shell 41. The turbine hub 43 includes a cylindrical turbine hub main body 43a and a disk portion 43b extending radially outward from the turbine hub main body 43a. The turbine shell 41 is fixed to the disc portion 43b by a plurality of rivets 44 together with a driven plate 62 described later.

  A first thrust washer 71 is provided between the turbine hub 43 and the inner peripheral portion of the front cover 2 in the axial direction. The first thrust washer 71 is pressed against the front cover 2 by a fixed plate 72. A second thrust bearing 73 is provided between the turbine hub 43 and the impeller hub 33 in the axial direction. The first thrust washer 71 and the second thrust bearing 73 allow the turbine 4 to rotate with respect to the front cover 2 and the impeller 3 while being positioned in the axial direction.

  As shown in FIG. 1, the lockup device 5 is disposed between the front cover 2 and the turbine 4 and mainly elastically connects the piston 51, the piston 51, and the turbine 4 in the rotational direction. And a damper mechanism 6.

  The piston 51 is a member for frictional engagement with the front cover 2, and is supported by the turbine hub 43 so as to be rotatable with respect to the turbine 4 and movable in the axial direction. An annular friction facing 52 is provided on the outer periphery of the piston 51. The configuration of the damper mechanism 6 will be described later.

<Configuration of torus>
As shown in FIG. 1, the torus T formed by the impeller 3 and the turbine 4 has an annular flow path P on the inner peripheral side. Specifically, the flow path P is disposed on the inner peripheral side of the impeller blade 32 and the turbine blade 42 and between the impeller shell 31 and the turbine shell 41 in the axial direction.

  As shown in FIG. 1, the impeller shell 31 mainly includes an annular first fixing portion 31a to which the impeller blade 32 is fixed, and an annular first flow path extending radially inward from the inner peripheral edge of the first fixing portion 31a. It has the formation part 31b and the cyclic | annular 1st support part 31c extended in the radial inside from the inner periphery of the 1st flow path formation part 31b. The first flow path forming portion 31b is curved so as to protrude toward the axial front cover 2 over the entire circumference. Here, the 1st fixing | fixed part 31a means the part formed along the impeller blade 32 among the impeller shells 31. FIG.

  As shown in FIG. 1, the turbine shell 41 mainly includes an annular second fixing portion 41 a to which the turbine blade 42 is fixed, and an annular second flow passage extending radially inward from the inner peripheral edge of the second fixing portion 41 a. It has the formation part 41b (1st part, reinforcement part), and the cyclic | annular 2nd support part 41c extended in the radial inside from the inner periphery of the 2nd flow-path formation part 41b. A plurality of holes 41d are formed in the second support portion 41c. Here, the 2nd fixing | fixed part 41a means the part formed along the turbine blade 42 among the turbine shells 41. FIG.

  As shown in FIG. 2, the second flow path forming portion 41b includes a curved portion 41e (second portion) and a cylindrical portion 41f extending in the axial direction from the inner periphery of the curved portion 41e. The curved portion 41e is curved so as to protrude from the inner peripheral edge of the second fixed portion 41a toward the impeller shell 31, and further curved so as to protrude toward the front cover 2. The curved portion 41e faces the first flow path forming portion 31b in the axial direction.

  Due to the shape of the first flow path forming portion 31b and the second flow path forming portion 41b, the axial dimension of the flow path P gradually decreases from the impeller blade 32 and the turbine blade 42 inward in the radial direction, and further increases in radius. It gradually increases as you go inward.

  Thus, in this fluid coupling 1, the flow path P is formed in the axial direction of the 1st flow path formation part 31b and the 2nd flow path formation part 41b, and the outer peripheral side of the cylindrical part 41f. For this reason, compared with the conventional fluid coupling, the axial distance from the outlet of the turbine 4 to the inlet of the impeller 3 is longer, and the region where the working fluid flowing out of the turbine 4 can stay is wider than before. .

<Configuration of damper mechanism>
A damper mechanism 6 is disposed on the inner peripheral side of the flow path P. Specifically, as shown in FIG. 2, the damper mechanism 6 mainly includes an annular drive plate 61 as a drive member fixed to the piston 51 and an annular driven plate 62 as a driven member fixed to the turbine 4. And a plurality of springs 63 held by the driven plate 62.

  The drive plate 61 mainly has a disk-shaped drive plate main body 61a and a plurality of protrusions 61b extending in the axial direction from the inner peripheral portion of the drive plate main body 61a. The drive plate body 61 a is fixed to the piston 51 by a plurality of rivets 53. The spring 63 is disposed between the rotation directions of the protrusions 61b.

  The driven plate 62 mainly includes a disc-shaped driven plate main body 62c, a cylindrical portion 62a extending in the axial direction from the outer peripheral portion of the driven plate main body 62c, and an annular shape extending radially inward from the inner peripheral portion of the driven plate main body 62c. The fixing part 62d. The fixing portion 62d is fixed to the disc portion 43b by the rivet 44 together with the second support portion 41c.

  The cylindrical part 62 a is fitted into the inner peripheral part of the cylindrical part 41 f of the turbine shell 41. That is, the cylindrical part 62a is in contact with the cylindrical part 41f in the radial direction, or is disposed with a slight gap between the cylindrical part 41f and the cylindrical part 41f in the radial direction. In addition, a plurality of first holding portions 62g and a plurality of first claw portions 62b bent inward in the radial direction are formed at the axial end of the cylindrical portion 62a. The first claw portion 62b extends inward in the radial direction.

  A plurality of second claw portions 62e bent in the axial direction are formed around the inner periphery of the driven plate main body 62c. The second claw portion 62e extends to the front cover 2 side. The fixed portion 62d is formed with a plurality of second holding portions 62f that are bent in the axial direction. The relative rotation between the drive plate 61 and the driven plate 62 is limited within a predetermined angle range by a stopper (not shown).

  The spring 63 is disposed on the inner peripheral side of the cylindrical portion 62a, is held in the axial direction by the first holding portion 62g and the driven plate main body 62c, and is radial by the cylindrical portion 62a and the second holding portion 62f. Is held in. The spring 63 is disposed between the rotation directions of the first claw portions 62b and between the rotation directions of the second claw portions 62e. A protrusion 61b of the drive plate 61 is inserted between the first claw 62b and the second claw 62e in the radial direction. The center of the spring 63 substantially coincides with the second flow path forming portion 41 b of the turbine shell 41 in the axial direction.

  Thus, in the fluid coupling 1, the damper mechanism 6 disposed on the inner peripheral side of the torus T is supported by the turbine shell 41.

<Dimensions>
Here, the dimensional relationship of each part is demonstrated using FIG.

  The maximum dimension of the torus T in the axial direction (the maximum distance between the first fixing part 31a and the second fixing part 41a in the axial direction) is L, and the minimum dimension of the flow path P in the axial direction (the first flow path forming part 31b and the first fixing part 31a). When S is the minimum distance between the two flow path forming portions 41b in the axial direction, the fluid coupling 1 satisfies the following relational expression (1).

S / L ≧ 0.3 (1)
This relational expression (1) indicates the ratio of the axial dimension of the flow path P to the axial dimension of the torus T.

  Further, when the larger one of the maximum dimension in the radial direction of the impeller blade 32 and the maximum dimension in the radial direction of the turbine blade 42 is H, the fluid coupling 1 satisfies the following relational expression (2).

0.8 ≦ L / H ≦ 1.0 (2)
This relational expression (2) indicates the flatness of the torus T, which means that the torus T has a flat shape that is long in the radial direction.

  When the outer diameter of the annular torus T is D, the fluid coupling 1 satisfies the following relational expression (3).

0.1 ≦ L / D ≦ 0.15 (3)
This relational expression (3) indicates the thinness ratio of the torus T, and means that the outer diameter position of the torus T is relatively outside in the radial direction with respect to the axial dimension of the torus T.

  Further, when the radial dimension of the end portion where the impeller blade 32 faces the turbine blade 42 in the axial direction and the radial dimension of the end portion where the turbine blade 42 faces the impeller blade 32 in the axial direction is larger, B2 The fluid coupling 1 satisfies the following relational expression (4).

B2 / L ≦ 1.0 (4)
This relational expression (4) means that the flow path P is widely secured.

  Further, the turbine blade 42 has a tapered portion 42a facing the impeller blade 32 in the axial direction on the radially outer side. When the angle formed by the tapered portion 42a and a plane orthogonal to the rotation axis OO is θ, the fluid coupling 1 satisfies the following relational expression (5).

10 ° ≦ θ ≦ 30 ° (5)
Furthermore, when the maximum dimension of the taper portion 42a in the radial direction is B1, the fluid coupling 1 satisfies the following relational expression (6).

0.15 ≦ B1 / H ≦ 0.3 (6)
These relational expressions (5) and (6) mean that the radially outer portion of the turbine blade 42 is cut obliquely.

<Operation>
The operation of the fluid coupling 1 will be described with reference to FIG.

  When the lockup device 5 is connected, the hydraulic oil between the piston 51 and the front cover 2 is discharged. As a result, the oil pressure on the turbine 4 side of the piston 51 becomes higher than that on the front cover 2 side, and the piston 51 moves to the front cover 2 side. Thereby, the friction facing 52 of the piston 51 is pressed against the front cover 2, and the torque input to the front cover 2 is input to the damper mechanism 6 via the piston 51.

  In the damper mechanism 6, a plurality of springs 63 are compressed between a drive plate 61 fixed to the piston 51 and a driven plate 62 fixed to the turbine 4, and torsional vibrations and the like generated during connection are absorbed. When the piston 51 rotates by a predetermined angle with respect to the turbine 4, a stopper (not shown) of the damper mechanism 6 is operated, and torque input to the piston 51 is transmitted to the turbine 4 through the damper mechanism 6.

  On the other hand, when the lockup device 5 is disconnected, hydraulic oil is supplied from a hydraulic pump (not shown) between the piston 51 and the front cover 2. As a result, the hydraulic pressure on the front cover 2 side of the piston 51 becomes higher than that on the turbine 4 side, and the piston 51 moves to the turbine 4 side. As a result, the frictional engagement between the piston 51 and the front cover 2 is released, and the piston 51 can rotate with respect to the front cover 2.

  In this case, torque is transmitted from the impeller 3 to the turbine 4 via the working fluid. Specifically, as shown in FIG. 1, the working fluid flows from the outlet (outer peripheral portion) of the impeller 3 to the inlet (outer peripheral portion) of the turbine 4. At this time, the working fluid collides with the turbine blade 42 and torque is transmitted to the turbine 4. The working fluid that has flowed into the turbine 4 flows between the turbine blades 42, and flows from the outlet of the turbine 4 (periphery inner periphery of the turbine blade 42) to the inlet of the impeller 3 (periphery inner periphery of the impeller blade 32). Torque is transmitted from the impeller 3 to the turbine 4 by the flow of the working fluid.

<Flow of working fluid>
Here, the flow of the working fluid in the torus T will be described in more detail with reference to FIGS. 3 and 4. FIG. 3 shows the result of analyzing the state in the torus by CFD (Computational Fluid Dynamic). Specifically, FIG. 3A shows the case of the fluid coupling 1, and FIG. 3B shows the case of the conventional fluid coupling. In FIG. 3, the flow direction of the working fluid in the torus is indicated by an arrow, and the pressure distribution of the working fluid is indicated by a color. Specifically, in FIG. 3, when the green area A1 is used as a reference, the blue area A2 has a lower pressure than the green area A1, and the orange area A3 has a higher pressure than the green area A1. FIG. 4 shows the capacity factor at each speed ratio (Speed Ratio) in FIGS. 3 (a) and 3 (b).

  As shown in FIGS. 3 (a) and 3 (b), the pressure of the working fluid is higher in the region on the inner peripheral side of the torus (around the turbine outlet and around the impeller inlet) than in other regions. This is because, in the region from the turbine outlet to the impeller inlet, only the centrifugal force acts mainly on the working fluid, and the flow velocity of the working fluid decreases.

  As shown in FIG. 3B, in the conventional fluid coupling, the pressure of the working fluid increases from the turbine outlet to the impeller inlet. Turbine blades and impeller blades are arranged in the high pressure regions H11 and H12. For this reason, when the working fluid flows out of the turbine or when the working fluid flows into the impeller, the fluctuation of the pressure acting on each blade increases. When the pressure fluctuation of the blade increases, fluid noise is generated and the impeller blade is damaged.

  On the other hand, as shown in FIG. 3A, in this fluid coupling 1, the flow path P is provided in the inner peripheral portion of the torus T, and the distance from the turbine 4 outlet to the impeller 3 inlet is longer than that of the conventional product. . As a result, a configuration in which the turbine blade 42 and the impeller blade 32 do not exist in the high pressure regions H1 and H2 can be realized, and the influence of the working fluid flowing out from the turbine 4 on the pressure state at the inlet of the impeller 3 can be reduced. it can. Thereby, the pressure fluctuation of the turbine blade 42 and the impeller blade 32 is suppressed as compared with the conventional product.

  And the flow of the working fluid from the turbine 4 to the impeller 3 becomes smooth by suppressing a pressure fluctuation. Thereby, as shown in FIG. 4, for example, the capacity coefficient is improved as compared with the conventional product. Furthermore, even if a coring is not provided, a capacity coefficient equal to or higher than that of a conventional product in which a coring is provided in the turbine and the impeller can be realized.

<Effect>
The effects obtained by the fluid coupling 1 are as follows.

(1) Improvement of Capacity Coefficient In this fluid coupling 1, a flow path P is formed in the inner peripheral portion of the torus T in order to secure an axial distance from the turbine 4 outlet to the impeller 3 inlet. As a result, the pressure fluctuation of the impeller blade 32 is suppressed as compared with the conventional product as described above. Thereby, in this fluid coupling 1, the flow of the working fluid from the turbine 4 to the impeller 3 becomes smooth, and a capacity coefficient improves compared with a conventional product. Further, in the fluid coupling 1, a capacity coefficient equal to or higher than that of a conventional product in which a coring is provided in the turbine and the impeller can be obtained without providing a coring.

  Further, the fluid coupling 1 satisfies the following relational expressions (1) to (3).

S / L ≧ 0.3 (1)
0.8 ≦ L / H ≦ 1.0 (2)
0.1 ≦ L / D ≦ 0.15 (3)
B2 / L ≦ 1.0 (4)
These relational expressions (1) to (4) indicate that the fluid coupling 1 has a flow path P having a large axial dimension on the inner peripheral side of the torus T, and that the torus T is compared with the conventional product. Means flat and thin. By satisfying these relational expressions, the capacity coefficient is more reliably improved.

(2) Miniaturization a)
In this fluid coupling 1, the turbine blade 42 has a tapered portion 42 a that faces the impeller blade 32 in the axial direction on the radially outer side. Thereby, the turbine 4 can be arranged closer to the impeller 3 and the axial dimension of the torus T can be shortened. That is, the size of the fluid coupling 1 can be reduced.

  In particular, the fluid coupling 1 satisfies the following relational expressions (5) and (6).

10 ° ≦ θ ≦ 30 ° (5)
0.15 ≦ B1 / H ≦ 0.3 (6)
By satisfying these relational expressions, it is possible to reduce the size within a range that does not affect the capacity coefficient of the fluid coupling 1.

b)
In the fluid coupling 1, the damper mechanism 6 is disposed on the inner peripheral side of the torus T. For this reason, the space on the inner peripheral side of the torus T can be used effectively, and downsizing can be realized.

(3) Reduction of Manufacturing Cost In this fluid coupling 1, the outer peripheral portion of the damper mechanism 6 is supported in the radial direction by the turbine shell 41. Specifically, the cylindrical portion 62 a of the driven plate 62 is supported by the cylindrical portion 41 f of the turbine shell 41. As a result, the turbine shell 41 can prevent elastic deformation of the driven plate 62 in the radial direction due to centrifugal force. Further, the allowable deformation amount of the turbine shell 41 is larger than the allowable deformation amount of the piston 51, and it is not necessary to increase the strength of the turbine shell 41.

  Thus, in this fluid coupling 1, it is not necessary to improve the strength of the member (for example, the driven plate 62) constituting the damper mechanism 6 as compared with the case where the outer peripheral portion of the damper mechanism is supported by the piston. Manufacturing costs can be reduced.

  Further, the second flow path forming portion 41b of the turbine shell 41 is substantially coincident with the center of the spring 63 in the axial direction. The center of the spring 63 substantially coincides with the outer peripheral portion of the driven plate 62 and the center of gravity of the spring 63. For this reason, the damper mechanism 6 can be efficiently supported in the radial direction.

  Further, since the second flow path forming portion 41b is a substantially disk-shaped portion extending in the radial direction, the rigidity in the radial direction is high. Thereby, the elastic deformation of the turbine shell 41 can be suppressed.

<Other embodiments>
The specific configuration of the present invention is not limited to the above-described embodiment, and various changes and modifications can be made without departing from the scope of the invention.

(1)
In the above-described embodiment, the flow path P includes a portion in which the axial dimension gradually increases as it goes radially inward. However, the shape of the flow path P is not limited to this. For example, the same effect can be obtained even when the axial dimension of the flow path P does not change as it goes radially inward.

(2)
The second flow path forming portion 41b is curved in the axial direction, but is not limited to this shape. For example, the second flow path forming portion 41b may be a disk-shaped portion that extends straight in the radial direction. In this case, if the flow path P is secured, the capacity coefficient is improved, and the strength of the turbine shell 41 is secured, so that the manufacturing cost can be reduced.

Schematic diagram of vertical cross section of fluid coupling (first embodiment) Partial sectional view of the damper mechanism 6 and its surroundings (first embodiment) Comparison diagram of working fluid flow and pressure distribution (first embodiment and prior art) Graph showing capacity coefficient (first embodiment and prior art)

Explanation of symbols

1 Fluid coupling (fluid torque transmission device)
DESCRIPTION OF SYMBOLS 2 Front cover 3 Impeller 4 Turbine 5 Lockup apparatus 6 Damper mechanism 31 Impeller shell 31a 1st fixing | fixed part 31b 1st flow-path formation part 31c 1st support part 32 Impeller blade 33 Impeller hub 41 Turbine shell 41a 2nd fixing | fixed part 41b 2nd Flow path forming part (first part, reinforcing part)
41c 2nd support part 41d Hole 41e Bending part (2nd part)
41f Tubular portion 42 Turbine blade 43 Turbine hub 44 Rivet 51 Piston 61 Drive plate (drive member)
61a Drive plate body 61b Protruding portion 62 Driven plate (driven member)
62a cylindrical part 62b first claw part 62c driven plate main body 62d fixing part 63 spring (elastic member)
T torus P flow path

Claims (8)

A fluid coupling for transmitting torque via a fluid,
A front cover to which the torque is input;
An impeller fixed to the front cover, forming a fluid chamber filled with the fluid, and having an impeller shell and a plurality of impeller blades fixed to the impeller shell;
A turbine having a turbine shell and a plurality of turbine blades fixed to the turbine shell, the turbine being disposed opposite to the impeller in the fluid chamber,
The impeller shell includes an annular first fixing portion to which the impeller blade is fixed, an annular first flow passage forming portion that extends radially inward from an inner periphery of the first fixing portion, and the first flow passage formation. An annular first support portion extending radially inward from the inner peripheral edge of the portion,
The turbine shell is arranged to extend inward in the radial direction from the inner periphery of the second fixing portion to which the turbine blade is fixed, and to face the first flow path forming portion in the axial direction. An annular second flow path forming portion, and an annular second support portion extending radially inward from the inner periphery of the second flow path forming portion,
The flow path formed between the first and second flow path forming portions in the axial direction includes a portion where the axial dimension increases as it goes inward in the radial direction or a portion where the axial dimension does not change.
Fluid coupling. The first flow path forming portion has an annular first portion extending radially inward from an inner peripheral edge of the first fixed portion,
The second flow path forming portion includes an annular second portion extending radially inward from an inner peripheral edge of the second fixing portion, a cylindrical portion extending axially from the inner peripheral edge of the second portion toward the impeller shell, have,
The fluid coupling according to claim 1. The second portion has a curved portion that curves so as to protrude in the axial direction toward the front cover.
The fluid coupling according to claim 2. When the maximum distance between the axial directions of the first and second fixing portions is L, and the minimum distance between the axial directions of the first and second portions is S, S / L ≧ 0.3 is satisfied.
The fluid coupling according to claim 2 or 3. When the maximum distance between the axial directions of the first and second fixed portions is L, and the larger one of the maximum dimension in the radial direction of the impeller blade and the maximum dimension in the radial direction of the turbine blade is H, 0.8 ≦ L / H ≦ 1.0 is satisfied,
The fluid coupling according to any one of claims 1 to 4. L is the maximum distance between the first and second fixed portions in the axial direction, and the distance from the rotary shaft to the radially outer end of the impeller blade and from the rotary shaft to the radially outer end of the turbine blade. If the larger of the distances is D, 0.1 ≦ L / D ≦ 0.15 is satisfied,
The fluid coupling according to any one of claims 1 to 5. When the maximum distance between the first and second fixed portions in the axial direction is L, and the outer diameter of the torus formed by the impeller and the turbine is B2, B2 / L ≦ 1.0 is satisfied.
The fluid coupling according to any one of claims 1 to 6. The turbine blade has a tapered portion that is axially opposed to the impeller on the radially outer side,
When the angle formed by the tapered portion and a plane perpendicular to the rotation axis is θ, 10 ° ≦ θ ≦ 30 ° is satisfied,
When the maximum dimension in the radial direction of the tapered portion is B1, and the larger one of the maximum dimension in the radial direction of the impeller blade and the maximum dimension in the radial direction of the turbine blade is H, 0.15 ≦ B1 / H ≦ 0. 3 is satisfied,
The fluid coupling according to any one of claims 1 to 7.