Power transmission device

Abstract

To provide a power transmission device capable of improving the reliability of a spline while suppressing an increase in the rotation resistance of a gear part.SOLUTION: A power transmission device 1 includes an input shaft 20 connected via a damper 14 fitted to a spline part 20a to a flywheel 11 mounted to an output shaft 10 of an engine, a wet type friction clutch 12 mounted between the input shaft and a transmission and capable of transmitting the rotation of the input shaft to the transmission, and a working fluid supply part 13 having a casing part 30 through which the input shaft passes for dividing the damper side and the wet type friction clutch side, and a drive gear 31 to be rotated in the casing part for supplying working fluid to the wet type friction clutch, the drive gear having a gear part 31a to be rotationally actuated on the same axis with the input shaft in the casing part, and a drive part extending from the gear part to the damper side while passing through the casing part, and fitted to the spline part of the input shaft for transmitting the rotation of the input shaft to the gear part, in an integral form.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present disclosure relates to a power transmission device.

Background Art

[0002] A power transmission device for transmitting the power of an engine to a transmission is provided between the engine and the transmission. In this power transmission device, the input shaft is connected to a flywheel mounted on the output shaft of the engine via a damper for absorbing the rotational fluctuations of the engine, or a fluid coupling such as a torque converter. A spline is formed on the input shaft of the power transmission device, and the connection between the damper or the fluid coupling and the input shaft is made via this spline.

[0003] On the other hand, a clutch for blocking the transmission of power from the engine to the transmission may be provided between the input shaft of the power transmission device and the transmission. When a wet friction clutch is used as such a clutch, an operating fluid supply means such as a hydraulic pump is required to supply the operating fluid to the wet friction clutch.

[0004] For example, in Patent Document 1, the operating fluid supply means is constituted by a gear pump, and a drive hub that is spline-coupled to the input shaft is provided between the damper and the pump gear separately from the pump gear of the gear pump. The drive hub transmits the rotation of the input shaft to the pump gear by fitting a plurality of protrusions into the pump gear.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] In the power transmission device of Patent Document 1, the pump gear and the drive hub are separate components in consideration of assembly. Although not described in detail in Patent Document 1, the pump gear is pivotally supported by a retainer on the wet friction clutch side.

[0007] In a power transmission device with such a configuration, the pump gear is supported by the retainer and rotates. However, since the support surface with the retainer is narrow, an event may occur in which the pump gear tilts with respect to the retainer due to the rotational movement, and there is a problem that the rotational resistance increases due to the tilt of the pump gear. In addition, the drive hub rotates integrally with the input shaft by fitting with the spline portion of the input shaft. However, since the portion fitting with the spline portion is short, it is easily worn, and the reliability of the spline may decrease.

[0008] Therefore, an object of the present disclosure is to provide a power transmission device capable of suppressing an increase in rotational resistance of a gear portion and improving the reliability of a spline.

Means for Solving the Problems

[0009] The present disclosure has been made to solve at least a part of the above-described problems and can be realized as the following aspects or application examples.

[0010] The power transmission device according to this application example is a power transmission device interposed between an engine and a transmission, capable of transmitting the power of the engine to the transmission. It has a spline portion, and is connected to a flywheel mounted on the output shaft of the engine via a damper that fits into the spline portion. It includes an input shaft, a wet friction clutch interposed between the input shaft and the transmission and capable of transmitting the rotation of the input shaft to the transmission, a casing portion that partitions the damper side and the wet friction clutch side while allowing the input shaft to pass through, and a working fluid supply portion having a drive gear that rotates within the casing portion to supply working fluid to the wet friction clutch. The drive gear includes a gear portion that rotates coaxially with the input shaft within the casing portion, and a drive portion that extends from the gear portion through the casing portion to the damper side, fits into the spline portion of the input shaft, and transmits the rotation of the input shaft to the gear portion, and is characterized in that they are integrated.

[0011] In this way, since the drive gear is integrated with the gear portion and the drive portion that extends through the casing portion to the damper side, the support of the gear portion is stable and tilting can be suppressed. Also, since the portion that fits with the spline portion can be made long, wear of the drive portion can be suppressed, and the reliability of the spline is improved. Thereby, an increase in the rotational resistance of the gear portion can be suppressed, and the reliability of the spline can be improved.

Brief Description of the Drawings

[0012]

Figure 1

Figure 2

Best Mode for Carrying Out the Invention

[0013] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a schematic cross-sectional view showing the overall configuration of the power transmission device of the present embodiment. The power transmission device 1 is interposed between an engine and a transmission (both not shown). FIG. 2 is a perspective view showing the configuration of the drive gear.

[0014] At the end of the output shaft 10 of the engine, a flywheel 11 is attached and fixed by a plurality of bolts 11a, and the flywheel 11 rotates together with the output shaft 10 during engine operation.

[0015] On the other hand, the power transmission device 1 includes a wet friction clutch 12 and a hydraulic pump (working fluid supply unit) 13. The wet friction clutch 12 includes an input shaft 20 arranged on the same axis as the output shaft 10 of the engine, and the output side is connected to the input shaft (not shown) of the transmission.

[0016] The wet friction clutch 12 is configured to be actuated by the working oil supplied from the hydraulic pump 13. When connected, it transmits the power from the engine to the transmission, and when disconnected, it cuts off the transmission of power from the engine to the transmission. The wet friction clutch 12 itself is a conventionally known one, and a detailed description of its configuration will be omitted here.

[0017] The input shaft 20 of the wet friction clutch 12 passes through the drive gear 31 of the hydraulic pump 13 described later and extends toward the engine side. On its peripheral surface, a spline portion 20a having splines parallel to the central axis is formed over a predetermined region from the engine-side end.

[0018] A damper 14 is interposed between the flywheel 11 and the input shaft 20 to transmit the power of the engine to the input shaft 20 while absorbing the rotational fluctuations and vibrations of the engine. The damper 14 includes an annular input plate 14b fixed to the flywheel 11 by a plurality of bolts 14a on the input side, and a damper hub 14d connected to the input plate 14b via a damper spring 14c on the output side.

[0019] The damper hub 14d of the damper 14 is formed with a through hole having a central axis that coincides with the central axis of the output shaft 10 of the engine. On the inner peripheral surface of the through hole, teeth corresponding to the splines formed on the spline portion 20a of the input shaft 20 are formed. The input shaft 20 is inserted into the through hole of the damper hub 14d, and the damper hub 14d is fitted to the spline portion 20a of the input shaft 20.

[0020] The hydraulic pump 13 is a gear pump and has a casing portion 30 fixed to the housing 15 of the power transmission device 1 and a drive gear 31 that rotates within the casing portion 30 to supply the wet friction clutch 12 with hydraulic fluid.

[0021] The casing portion 30 has a substantially disk shape. The input shaft 20 passes through the central portion while partitioning the damper 14 side and the wet friction clutch 12 side. A space for accommodating the gear portion 31a of the drive gear 31 is formed in the central portion of the casing portion 30.

[0022] The drive gear 31 rotates on the same axis as the input shaft 20 within the casing portion 30. It has a gear portion 31a that supplies the working oil, which is the working fluid with increased pressure, to the outside, and a drive portion 31b that extends to the damper 14 side through the casing portion 30 and has a cylindrical shape. The gear portion 31a and the drive portion 31b are integrally formed.

[0023] As shown in FIG. 2, the gear portion 31a has a planar shape orthogonal to the input shaft 20. The outer periphery of the gear portion 31a has a gear shape. The drive portion 31b has a cylindrical shape, and a tool engagement portion 31c having a hexagonal cross-sectional outer shape is provided on the side opposite to the gear portion 31a. Further, teeth corresponding to the splines formed on the spline portion 20a of the input shaft 20 are formed on the inner peripheral surface of the drive portion 31b (the teeth formed on the drive portion 31b are omitted in FIG. 2). By the teeth formed on the drive portion 31b being spline-fitted to the spline portion 20a of the input shaft 20, the rotation of the input shaft 20 is transmitted to the gear portion 31a, and the gear portion 31a rotates integrally with the drive portion 31b.

[0024] Here, as described above, since the gear portion 31a and the drive portion 31b are integrated, the length of the portion where the drive portion 31b is spline-fitted with the spline portion 20a of the input shaft 20 becomes long. Specifically, it is spline-fitted from the tip of the drive portion 31b (the side of the damper 14) to the front of the first seal ring 40, which will be described later, that is, to the substantially central position in the axial direction of the gear portion 31a.

[0025] And, as shown in FIG. 1, the inner peripheral surface of the gear portion 31a of the drive gear 31 is rotatably supported on the outer peripheral surface of the input shaft 20 via a first seal ring (first seal portion) 40, and the outer peripheral surface of the drive portion 31b of the drive gear 31 is rotatably supported on the casing portion 30 of the hydraulic pump 13 via a second seal ring (second seal portion) 41.

[0026] Therefore, since the drive gear 31 is spline-fitted to the spline portion 20a of the input shaft 20 and is supported by the casing portion 30 and the input shaft 20 via two seal rings, the generation of vibration when the drive gear 31 rotates can be favorably suppressed, and it is possible to suppress the increase in rotational resistance due to the reduction of the inclination of the drive gear 31 accompanying the rotational movement.

[0027] When the power transmission device 1 is configured in this way, the power of the engine is transmitted from the flywheel 11 fixed to the output shaft 10 to the input shaft 20 of the wet friction clutch 12 via the damper 14. And when the wet friction clutch 12 is connected, the power of the engine is transmitted to the transmission via the wet friction clutch 12, while when the wet friction clutch 12 is disengaged, the transmission of the engine power to the transmission is interrupted.

[0028] Also, a part of the power of the engine transmitted to the input shaft 20 causes the hydraulic pump 13 to operate by rotating the gear portion 31a integrated with the drive portion 31b via the drive portion 31b of the drive gear 31 spline-fitted to the input shaft 20. The hydraulic oil whose pressure has been increased by the operation of the hydraulic pump 13 is supplied to the wet friction clutch 12 and is used for the operation of the wet friction clutch 12.

[0029] Since the flywheel 11 is fixed to the output shaft 10 of the engine, the flywheel 11 fluctuates due to the vibration associated with the operation of the engine, and this fluctuation is transmitted to the damper 14 via the flywheel 11. At this time, since the drive portion 31b of the drive gear 31 is provided separately from the damper hub 14d of the damper 14, the fluctuation of the damper 14 associated with the fluctuation of the flywheel 11 is not directly transmitted to the drive portion 31b. Therefore, it is possible to favorably suppress wear and deformation of the drive gear 31, the first seal ring 40, and the second seal ring 41 associated with the transmission of the fluctuation, and it is possible to favorably suppress the vibration noise and occurrence of failure of the hydraulic pump 13 caused by the fluctuation and vibration transmitted from the engine.

[0030] As described above, in the power transmission device according to the present embodiment, the drive gear 31 is integrally formed by the gear portion 31a and the drive portion 31b that penetrates the casing portion 30 and extends to the damper 14 side, so that the support of the gear portion 31a is stabilized and tilting can be suppressed. In addition, since the portion that fits with the spline portion 20a can be made long, wear of the drive portion 31b can be suppressed, and the reliability of the spline is improved. Thereby, an increase in the rotational resistance of the gear portion 31a can be suppressed, and the reliability of the spline can be improved.

[0031] With the above, the description of the power transmission device according to the embodiment of the present invention is completed, but the present invention is not limited to the above embodiment.

[0032] Further, in the above embodiment, the hydraulic pump is a gear pump, but the type of the hydraulic pump is not limited to this, and any type of hydraulic pump having a rotary input member that rotates on the same axis as the input shaft, such as the gear portion of the drive gear, may be used.

[0033] Further, in the above embodiment, hydraulic oil is used as the working fluid used for the wet friction clutch, but the type of the working fluid is not limited to this.

Explanation of reference numerals

[0034] 1 Power transmission device 10 Output shaft 11 Flywheel 11a Bolt 12 Wet friction clutch 13 Hydraulic pump (operating fluid supply section) 14 Damper 14a Bolt 14b Input plate 14c Damper spring 14d Damper hub 15 Housing 20 Input shaft 20a Spline section 30 Casing section 31 Driving gear 31a Gear section 31b Driving section 31c Tool engagement section 40 First seal ring (first seal member) 41 Second seal ring (second seal member)

Claims

【Claim 1】 In a power transmission device interposed between an engine and a transmission and capable of transmitting the power of the engine to the transmission, having a spline portion, an input shaft connected to a flywheel mounted on an output shaft of the engine via a damper fitted to the spline portion, a wet friction clutch interposed between the input shaft and the transmission and capable of transmitting the rotation of the input shaft to the transmission, a casing portion that partitions the damper side and the wet friction clutch side while allowing the input shaft to pass through, and a drive gear that rotates within the casing portion to supply working fluid to the wet friction clutch, and comprising a working fluid supply portion, the drive gear is characterized in that a gear portion that rotates on the same axis as the input shaft within the casing portion and a drive portion that extends from the gear portion through the casing portion to the damper side, fits into the spline portion of the input shaft, and transmits the rotation of the input shaft to the gear portion are integrated, a power transmission device.

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