JPH0320142A - Power transmission - Google Patents

Abstract

PURPOSE:To maintain a differential limit between respective turning members as well as to improve the extent of rectilinear stability by letting a connecting means, transmitting input torque to each transmission member, perform intermission of the torque transfer, and providing an energizing means giving clamping force to a friction limiting means even when each clutch is released. CONSTITUTION:In an interval between hub members 51 and 53, there is provided a multiple disk clutch 93 which joins a lot of friction disk set up alternately by means of spline engagement. This multiple disk clutch 93 is always clamped with specified pressing force in a gap with a collar 55 by a disk spring 95. Consequently, it transmits an input torque to each of symmetrical rear wheels. Even if clamping force of multiple disk clutches 57, 59 is weakened or opened free, differential motion between these symmetrical rear wheels is limited by dont of the clamping force of the multiple disk clutch 93, so that these rear wheels will not come to state of free rotation each other. Accordingly, rectilinear stability in a vehicle is thus improvable.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a power transmission device used in a vehicle or the like.

(Prior Art) Japanese Patent Laid-Open No. 62-94421 describes a "rear wheel drive device for a vehicle." This device can be used, for example, for front engine/front drive (FF) based four-wheel drive (
4WD) Used on the rear wheels of a vehicle, it has a pair of hydraulic clutches that transmit the driving force from the engine to the left and right rear wheels separately, and the engagement force of these hydraulic clutches is specifically adjusted to the left and right to improve maneuverability and driving. Stability can be improved, and switching between 4WD and two-wheel drive (2WD) states can be achieved by opening and closing the hydraulic clutch.

In this example, if the engagement force of each hydraulic clutch is weakened or released to create a 2WD state, not only will fuel efficiency be improved, but the characteristics of a front-wheel drive vehicle will be obtained, and high-speed straight-line stability will be improved. However, in this case, the left and right rear wheels are free-rotating relative to each other, resulting in a corresponding loss of straight-line stability.

(Problems to be Solved by the Invention) Therefore, an object of the present invention is to provide a power transmission device that can further improve straight-line stability.

C Configuration of the Invention] (Means for Solving the Problems) The power transmission device of the present invention includes a pair of transmission members arranged to be relatively rotatable, and a pair of clutches that separately transmit input torque to these transmission members. a pair of connecting means for individually engaging and disconnecting these clutches; a friction limiting means for limiting differential motion between the two transmission members; and applying a fastening force to the friction limiting means when at least the pair of clutches is released. The invention is characterized by comprising a biasing means for.

(Operation) Each clutch transmits input torque from, for example, an engine to each transmission member. Each coupling means performs on/off transmission of torque via each clutch. Even when each clutch is released, the friction limiting means maintains the limited differential between the rotating members, so that free mutual rotation does not occur.

(Example) One embodiment will be explained with reference to FIG. 1 and FIG. 2.

Hereinafter, the left and right directions refer to the left and right directions in these drawings, and the upper part of Figure 1 is the front of the vehicle shown in Figure 2 (the upper part of Figure 2).
corresponds to

First, the configuration will be explained.

The vehicle in Figure 2 is a FF-based 4WD vehicle, and its power system consists of engine 1, transmission 3, transfer 5, and front differential 7 (differential device on the front wheel side).
, front axles 9, 11, left and right front wheels 13.15, propeller shaft 17, rear differential 19 (power transmission device in this embodiment used as a differential device on the rear wheel side), rear axles 21, 23, left and right rear wheels 25. It consists of .27, etc.

The casing 29 of the rear differential 19 is a bearing 31.33
is rotatably supported by the differential carrier 35.

Further, in the differential carrier 35, a drive pinion shaft 37 connected to the propeller shaft 17 side is connected to the bearing 3.
It is rotatably supported by 9.41.43, and a drive pinion gear 45 is integrally formed at the rear end.

A ring gear 47 that meshes with this gear 45 is fixed to the casing 29 by bolts 49. In this way, the casing 29 is rotationally driven by the driving force from the engine 1.

Inside the casing 29 are a pair of hub members 51 and 53 (
(transmission member) are arranged so as to be relatively rotatable, and a collar 55 is arranged between them. Between the casing 29 and the hub members 51 and 53 are a pair of clutch clutches 5 in which a number of friction clutches arranged alternately are individually spline-engaged.
7.59 (clutch) is installed. A pressure receiving ring 60 fixed to the two casing sides is arranged between these and fixed to the inner periphery of the casing 29. A left rear axle 21 is spline-coupled to the left hub member 51, and a right rear axle 23 is spline-coupled to the right hub member 53.

Therefore, the driving force from the engine 1 is transmitted to the multi-disc clutch 57.
The signal is transmitted to the rear wheel 25 side via the multi-disc clutch 59, and is transmitted to the rear wheel 27 side via the multi-disc clutch 59. Each multi-plate clutch 57.5
By adjusting the fastening forces 9 separately, the torque transmission ratio between the rear wheels 25 and 27 can be changed. Also, multi-plate clutch 5
If 7.59 is released, the transmission of driving force to the rear wheels is cut off, and the vehicle enters a 2WD driving state.

The differential carrier 35 is provided with a pair of cylinder parts 61.63, each of which has a piston member 65.67 slidably engaged in a fluid-tight manner via an O-ring 69.71.
A pair of hydraulic actuators 73 and 75 (coupling means) are formed. Each piston member 65, 67 has a twenty dollar bearing 77, 77, a pressing ring 79, 79, respectively.
, push rods 81, 81, and pressure rings 83, 83 to press and engage the clutches 57, 59 with the pressure receiving ring 60. Note that the push rod 81 extends slidably through the casing 29.

Each hydraulic actuator 73, 75 is operated by supplying hydraulic pressure from a hydraulic source 85 to each hydraulic boat 89, 91 via a control valve device 87. The control valve device 87 is manually operated from the driver's seat or automatically operated according to steering conditions, road surface conditions, etc., and engages and disengages the multi-disc clutches 57 and 59 and adjusts the engagement force.

A multi-disc clutch 93 (friction limiting means) is provided between the hub members 51 and 53, in which a large number of alternately arranged friction plates are individually spline-engaged. This multi-plate clutch 93 is always fastened to the collar 55 with a predetermined pressing force by a disc spring 95 (biasing member). Therefore, even if the engagement force of the Tasaka clutch 57.59 is weakened or released, the differential between the left and right rear wheels 25.27 is maintained by the multi-plate clutch 93.
This fastening force prevents them from rotating freely with each other.

Next, the functions will be explained based on the performance of the vehicle shown in FIG.

When the engagement force of the multi-disc clutch 57, 59 is weakened or released, the vehicle approaches the FF 2WD driving state or changes to 2WD.
It will be in running condition. Therefore, fuel efficiency is improved accordingly, and straight-line stability is also improved. At this time, if the vehicle body attempts to rotate due to disturbances such as a crosswind, the rotation of the outer rear wheels is restricted by the differential braking force of the multi-disc clutch 93, thereby preventing rotation and improving straight-line stability. do.

Furthermore, for the same reason, tuck-in, in which the vehicle cuts into the inside of a corner due to a sudden increase in the cornering force of the front wheels when the accelerator pedal is released during a turn in a front-wheel drive vehicle, can be prevented or alleviated.

When the multi-disc clutches 57 and 59 are engaged, the vehicle enters the 4WD driving state, which improves all-terrain performance, and also limits the differential movement between the front and rear wheels, increasing straight-line stability as described above. Also, by adjusting the engagement force of the multi-plate clutch 57.59, the rear wheel 25.27
By significantly changing the driving force, maneuverability and stability can be improved.

In the present invention, the differential speed limiting means is not limited to the multi-disc clutch as in the embodiment, but may also be a viscous coupling, an externally operable dog clutch, or the like. The fastening force can also be configured to be applied only when both multi-plate clutches 57, 59 are released.

[Effects of the Invention] As described above, according to the power transmission device of the present invention, the straight-line stability of the vehicle can be significantly increased.

[Brief explanation of drawings]

FIG. 1 is a sectional view of one embodiment, and FIG. 2 is a skeleton mechanism diagram showing the power system of a vehicle using this embodiment.

Claims (1)

[Claims] A pair of transmission members arranged to be relatively rotatable, a pair of clutches that separately transmit input torque to these transmission members, and a connecting means that separately connects and disconnects these clutches,
A power transmission characterized by comprising: a friction limiting means for limiting differential motion between the two transmission members; and an urging member for applying a fastening force to the friction limiting means when at least the pair of clutches is released. Device.