JPH0714252U - Power transmission device - Google Patents

Abstract

(57) [Abstract] [Purpose] No seizure occurs between the crankshaft of the power transmission device and the boss of the front cover. [Structure] The power transmission device transmits power from an engine-side drive shaft 41 having a center hole 41a at its tip, and includes a torque converter 1 and a coupling mechanism 2. The torque converter 1 includes a front boss 42 having a groove 42a on the outer peripheral surface thereof and rotatably supported by the drive shaft center hole 41a, and a front cover 4 having an inner peripheral end fixed to the front boss 42. The connection mechanism 2 connects the crankshaft 41 and the front cover 4 to each other so as to be relatively rotatable within a predetermined angle range.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a power transmission device, and more particularly to a power transmission device that includes a torque converter and that transmits power from a crankshaft on the engine side.

[0002]

[Prior art]

 A torque converter is a device that has three types of impellers (impeller, turbine, stator) inside and transmits power by the fluid inside. In order to connect the torque converter and the crankshaft on the engine side to transmit power, the applicant of the present application has already proposed a connecting mechanism as shown in Japanese Patent Application No. 3-97529. Here, the crankshaft and the front cover of the torque converter are connected by a damper mechanism so as to be relatively rotatable within a predetermined angle range. The torque on the engine side is transmitted from the crankshaft to the coupling mechanism, and is transmitted to the front cover while the torsional vibration is absorbed by the damper mechanism of the coupling mechanism.

Here, the boss of the front cover is rotatably supported in the center hole at the rear end of the crankshaft.

[0004]

[Problems to be solved by the device]

 In the above-described conventional configuration, when torque fluctuation is transmitted from the crankshaft side to the front cover side, the damper mechanism operates to cause relative rotation between the crankshaft and the front cover. As a result, the center hole of the crankshaft and the boss of the front cover slide, causing friction between the two. As a result, the sliding part becomes hot and seizure may occur due to the generation of abrasion powder.

An object of the present invention is to prevent seizure between the crankshaft and the boss of the front cover.

[0006]

[Means for Solving the Problems]

 A power transmission device according to the present invention is a power transmission device for transmitting power from a crankshaft shaft having a center hole formed at an end portion on an output side, and includes a torque converter and a coupling mechanism. The torque converter includes a front boss that has a groove on its outer peripheral surface and is rotatably supported in a crankshaft center hole, and a front cover whose inner peripheral end is fixed to the front boss. The connecting mechanism connects the crankshaft and the front cover so as to be relatively rotatable within a predetermined angle range.

[0007]

[Action]

 In the power transmission device according to the present invention, the rotational force of the crankshaft is transmitted to the front cover of the torque converter via the coupling mechanism of the power transmission device. When torque fluctuation occurs on the engine side, the relative rotation occurs between the crankshaft and the front cover due to the operation of the connecting mechanism. At this time, the center hole of the crankshaft and the front boss repeatedly slide to generate friction. However, since the groove is formed on the outer peripheral surface of the front boss, it is possible to cool the sliding surface and discharge the abrasion powder. As a result, seizure on the sliding surface is prevented.

[0008]

【Example】

 FIG. 1 shows a power transmission device as an embodiment of the present invention. Here, O-O is the rotation center line of the torque converter. In FIG. 1, this power transmission device includes a torque converter 1 and a coupling mechanism 2 for transmitting torque from the engine side crankshaft 41 to the torque converter 1.

In the torque converter 1, a front cover 4 and an impeller shell 5 fixed to an outer peripheral wall 4 a of the front cover 4 form a hydraulic oil chamber. The inner peripheral end of the impeller shell 5 a is fixed to the impeller hub 31. A plurality of push-out portions 4b that are pushed forward in the axial direction (to the left in FIG. 1) in the circumferential direction are formed in the middle portion in the radial direction of the front cover 4. The connecting mechanism 2 is fixed to the pushing portion 4b so that the driving force from the engine side is input to the front cover 2. A flat friction surface 4c is formed on the inner wall on the outer peripheral side in the radial direction of the front cover 4.

A front boss 42 protruding toward the engine side (left side in FIGS. 1 and 2) is fixed to an inner peripheral end of the front cover 4. The front boss 42 is rotatably and movably supported in a center hole 41a formed at the rear end of the crankshaft 41 on the engine side. As is apparent from FIGS. 2 and 3, four grooves 42a extending in the axial direction are formed on the outer peripheral surface of the front boss 42 at equal intervals in the circumferential direction. As shown in FIG. 2, the bottom surface of the groove 42a is an inclined surface that inclines toward the center at an angle θ toward the tip. A predetermined axial gap is secured between the crankshaft 41 and the front boss 42 so that the front boss 42 can move in the axial direction. Particularly, each groove 42a communicates with the outside by a gap 43 between the root portion of the front boss 42 and the end surface 41b of the crankshaft 41. The outer peripheral surface of the front boss 42 is coated with an antiwear agent.

The hydraulic oil chamber in the torque converter 1 mainly includes an impeller 5, a turbine 6, a stator 7, and a lockup device 8. A plurality of impeller blades 5b are fixed inside the impeller shell 5a. The impeller 5 is constituted by the impeller shell 5a and the impeller blade 5b. A turbine 6 is arranged at a position facing the impeller 5. The turbine 6 is composed of a turbine shell 6a and a plurality of turbine blades 6b fixed to the turbine shell 6a. The inner peripheral end portion of the turbine shell 6a is fixed to the flange portion 9a of the turbine hub 9 by a plurality of rivets 10. The turbine hub 9 has a spline hole 11 that engages with an output shaft (not shown) on the inner peripheral portion. A plurality of bent claws 6c are fixed to the outer periphery of the turbine shell 6a. The bending claw 6c engages with the lockup device 8 and transmits the rotational force from the lockup device 8 to the turbine 6.

A stator 7 is arranged between the inner peripheral portion of the impeller 5 and the inner peripheral portion of the turbine 6. The stator 7 is for adjusting the direction of the hydraulic oil returned from the turbine 6 to the impeller 5, and is composed of an annular stator carrier 7a and a plurality of stator blades 7b formed on the outer peripheral surface of the stator carrier 7a. ing. The status 7 is connected to the inner race 12 via a one-way clutch mechanism.

The lockup device 8 is arranged between the front cover 4 and the turbine 6. The lockup device 8 has a disc-shaped piston 13 whose inner peripheral end is slidably supported on the outer peripheral surface of the turbine hub 9. A friction member 14 is bonded to the outer peripheral end of the piston 13 on the surface of the front cover 4 that faces the friction surface 4c. The piston 13 has a cylindrical end wall 13a extending axially rearward (rightward in FIG. 1) at the outer peripheral side end. A retaining plate 15 is arranged on the inner peripheral side of the end wall 13 a of the piston 13, and is fixed to the piston 13 by a rivet 16. The retaining plate 15 has a tubular portion that extends in an annular shape, and accommodates a plurality of torsion springs 17 that extend in the circumferential direction in the tubular portion. Further, the circumferential ends of the torsion springs 17 are supported by bending claws formed on the retaining plate 15. On the other hand, both ends of the torsion spring 17 are engaged with turbine claws 6c fixed to the outer peripheral portion of the turbine shell 6a. As a result, the piston 13 and the turbine 6 are elastically connected in the circumferential direction.

Next, the connecting mechanism 2 will be described. The connection mechanism 2 mainly includes a flexible plate 19 and a damper mechanism 20. The flexible plate 19 is a disk-shaped member and is elastically deformable in the axial direction. An inner peripheral end portion of the flexible plate 19 is fixed to an end surface 41b of the crank shaft 41 on the engine side with a bolt 44.

The damper mechanism 20 mainly includes a disc-shaped plate 21, a torsion spring 22, a first side plate 23, and a second side plate 24. The disc plate 21 has a plurality of window holes 21a extending in the circumferential direction on the outer peripheral side. The disc plate 21 has a hole 21b at a position corresponding to the push-out portion 4b of the front cover 4 at the inner peripheral end thereof, and the push-out portion 4b is inserted into this hole 21b and both are fixed by welding. There is. A torsion spring 22 extending in the circumferential direction is arranged in the window hole 21a. A first side plate 23 and a second side plate 24 are arranged on both sides of the disc plate 21. The first side plate 23 and the second side plate 24 are integrally fixed by rivets 25 at the outer peripheral edge. An outer peripheral end of the first side plate 23, which further extends to the outer peripheral side in the radial direction, is fixed to the outer peripheral outer end of the flexible plate 19 by a bolt 26a and a nut 26b. An annular protrusion 21 c is formed on the disc plate 21 on the inner periphery of the second side plate 24.

The first side plate 23 and the second side plate 24 have a cut-and-raised window hole portion at a position corresponding to the window hole 21 a of the disc plate 21, and the cut-and-raised window hole portion has a torsion spring 22. Holding By this torsion spring 22, the first side plate and the second side plates 23, 24 are elastically connected to the disc plate 21 fixed to the front cover 4 in the circumferential direction.

An annular cone spring 27, a friction plate 28, and a friction washer 29 are arranged between the inner peripheral end of the second side plate 24 and the disc plate 21 from the second side plate 24 side. The friction plate 28 has a protrusion that engages with the second side plate 24. The cone spring 27 biases the friction washer 29 toward the disc plate 21 side.

Next, the operation of the above embodiment will be described. The torque from the crankshaft 41 on the engine side is transmitted from the flexible plate 19 of the coupling mechanism 2 to the front cover 4 of the torque converter 1 via the damper mechanism 20. During this transmission, the torque fluctuation generated on the engine side is effectively absorbed by the damper mechanism 22. That is, when the first side plate 23 and the second side plate 24 are twisted with respect to the disc plate 21, the torsion spring 22 repeatedly expands and contracts, and the friction washer 29 slides to generate a predetermined hysteresis torque. To do. In this way, the torsional vibration transmitted from the coupling mechanism 2 to the torque converter 1 side is reduced.

During the above operation, relative rotation occurs between the crankshaft 41 and the front cover 4. Therefore, the center hole 41a of the crankshaft 41 and the front boss 42 frictionally slide. Since both sliding surfaces of the front boss 42 are coated with an antiwear agent, the amount of abrasion powder generated is small. Further, even if abrasion powder is generated, the abrasion powder accumulates in the groove 42a, and the amount of abrasion powder present on the sliding surface can be significantly reduced. Therefore, it is possible to suppress wear of the sliding surface and prevent seizure. Further, the abrasion powder collected in the groove 42a is discharged to the outside through the gap 43 along the inclined surface. Furthermore, since the outside air flows into the groove 42a from the gap 43, both sliding surfaces are sufficiently cooled. As a result, seizure on both sliding surfaces is even less likely to occur.

On the other hand, during power transmission, bending vibration acts on the crankshaft 41 in addition to the above-described torsional vibration. The bending vibration generated in the crankshaft 41 is first transmitted to the flexible plate 19 fixed to the crankshaft 41. The bending vibration is absorbed by the elastic deformation of the flexible plate 19. In this way, bending vibration transmitted from the coupling mechanism 2 to the torque converter 1 is reduced. Note that the front boss 42 slides in the axial direction with respect to the crankshaft 41 during transmission of the bending vibration described above. At this time as well, as with the occurrence of torsional vibration, seizure on the sliding surface is less likely to occur due to the groove 42a.

When the front cover 4 of the torque converter 1 rotates, the impeller 5 rotates with it. The rotation of the impeller 5 is connected to the turbine 6 via hydraulic oil. The flow of hydraulic oil returning from the turbine 6 to the impeller 5 is adjusted by the stator 7. Then, the rotation of the turbine 6 is transmitted to the output shaft (not shown) via the turbine hub 9.

[0022]

[Effect of device]

 In the power transmission device according to the present invention, relative rotation occurs between the crankshaft and the front cover, but the groove formed on the outer peripheral surface of the front boss enables cooling of the sliding surface and discharge of abrasion powder. ing. As a result, seizure on the sliding surface is prevented.

[Brief description of drawings]

FIG. 1 is a schematic vertical sectional view of a power transmission device as an embodiment of the present invention.

FIG. 2 is a partially enlarged view of FIG.

FIG. 3 is a sectional view taken along line III-III of FIG.

[Explanation of symbols]

 1 Torque Converter 2 Connection Mechanism 4 Front Cover 41 Crank Shaft 41a Center Hole 42 Front Boss 42a Groove

Claims (1)

[Scope of utility model registration request] 1. A power transmission device for transmitting power from a crankshaft having a center hole formed at an end portion on an output side, the power transmission device having a groove on an outer peripheral surface and rotatably supported in the crankshaft center hole. A front boss, a torque converter including a front cover having an inner peripheral end fixed to the front boss, and a coupling mechanism that couples the cran shaft and the front cover so as to be relatively rotatable within a predetermined angle range. Power transmission device equipped.