JPH0587162A - Hydraulic power transmission joint - Google Patents

Abstract

PURPOSE:To dispense with braking mechanism and attain compactness, light weight and cost reduction while managing with only low pressure-proof oil seal in a hydraulic power transmission joint used for the driving force distribution of a vehicle. CONSTITUTION:There are provided one orifice 16 serving as a flow resistance generating means, and a spool like switching valve 17 for controlling the conductive state between the orifice and a high pressure chamber 15. When the temperature reaches the specified value or higher, the switching valve 17 is switched into the closed state from the opened state by the displacement of an accumulator piston 22.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydraulic power transmission joint used for distributing a driving force of a vehicle.

[0002]

2. Description of the Related Art The applicant of the present application has proposed in Japanese Patent Application No. 2-8035 a hydraulic power transmission joint in which a brake is operated by an internal pressure acting on an accumulator piston when the joint temperature rises above a predetermined level. There is. That is,
This hydraulic power transmission joint is provided between a relatively rotatable input / output shaft, and includes a pump driven by a rotational speed difference between the two shafts, and means for generating flow resistance in a discharge passage of the pump, In a power transmission joint in which the transmission torque between the input and output shafts is controlled by flow resistance, an accumulator piston that moves due to expansion and contraction of oil enclosed in the joint and cannot move when the temperature of the joint rises to a predetermined value; A brake mechanism is provided for generating a friction torque between the input and output shafts by the pressure of the enclosed oil.

[0003]

However, in such a conventional hydraulic power transmission joint, the brake mechanism needs to be provided outside the accumulator piston, that is, outside the joint, and the mechanism is complicated, Moreover, there is a problem that it is large and expensive. Further, since the internal pressure of the joint is increased, it is necessary to enhance the pressure resistance of the oil seal and the like, which causes a problem that the cost is high.

The present invention has been made in view of the above-mentioned problems of the prior art, does not require a brake mechanism, and can be reduced in size, weight and cost, and the oil seal is pressure resistant. It is an object of the present invention to provide a hydraulic power transmission joint that requires a low cost.

[0005]

In order to achieve the above-mentioned object, the present invention is provided between input / output shafts capable of relative rotation,
A hydraulic pump driven by the differential rotation of the both shafts,
A high pressure chamber for collecting the discharge oil of the hydraulic pump, and a flow resistance generating means provided at the outlet from the high pressure chamber to the low pressure chamber in the joint,
In a hydraulic power transmission joint that includes an accumulator mechanism that absorbs expansion and contraction of enclosed oil and that transmits a torque according to a rotational speed difference between the two shafts, one orifice is provided as the flow resistance generating means, and the orifice is provided. A spool-shaped switching valve for controlling the conduction state between the high pressure chamber and the high pressure chamber is provided, and when the temperature exceeds a predetermined value, the switching valve is switched from the open state to the closed state by the displacement of the accumulator piston.

[0006]

In the present invention, at normal temperature, the accumulator piston does not move and the orifice is open, so that normal torque characteristics can be obtained. When the temperature rises above a certain value, the displacement of the accumulator piston causes
The switching valve is switched from the open state to the closed state. When the switching valve closes the orifice, the lock characteristic is obtained.

Since no brake mechanism is required,
The joint is small, lightweight and inexpensive. Further, the internal pressure of the joint does not increase, and the pressure resistance of the oil seal may be low.

[0008]

Embodiments of the present invention will be described below with reference to the drawings. 1 to 4 are views showing an embodiment of the present invention.
First, the configuration will be described. In FIG. 1, 1 is a housing, and the housing 1 is connected to an output shaft (not shown) and rotates integrally with the output shaft.

Reference numeral 2 denotes a cam, and the cam 2 is supported on the inner surface of the housing 1 so as to be rotatable by a predetermined angle. Cam 2
It has a cam surface 2A composed of a plurality of cam ridges and a cam valley, and has a plurality of protrusions 2B for positioning and torque transmission on the outer periphery thereof where the cam ridges are on the side surfaces. When the projection 2B of the cam 2 is engaged with the notch 1A formed in the housing 1 to rotate integrally with the housing 1 in the rotation direction of the rotor 3, and when the rotation direction of the rotor 3 changes, the cam 2 moves to the rotor 3
And the projection 2B of the cam 2 is rotated together with the housing 1
After rotating until it hits the notch 1A, it rotates integrally with the housing 1.

The rotor 3 is rotatably housed in the housing 1 and is coupled to the input shaft 4 so as to rotate integrally with the input shaft 4. A plurality of plunger chambers 5 are formed in the rotor 3 in the axial direction, and a plurality of plungers 6 are slidably accommodated in the plunger chamber 5 via return springs 7. Further, the rotor 3 is formed with a plurality of suction / discharge holes 8 so as to communicate with the respective plunger chambers 5.

Reference numeral 9 is a valve (valve body) having an intake port 10, an intake passage 11 and a discharge port 12 formed therein. Positioned and fixed to. A bearing 1 is provided between the input shaft 4 and the inner diameter of the valve 9.
4, the ring-shaped groove formed in the inner diameter portion of the valve 9 is sealed by the outer diameter surface of the bearing 14 to form the high pressure chamber 15.

The discharge port 12 communicates with the high pressure chamber 15 via a passage (not shown), and an orifice 16 as a flow resistance generating means is formed at the outlet of the high pressure chamber 15. The orifice 16 can communicate with the suction passage 11. 1
Reference numeral 7 is a spool valve that is provided apart from the shaft center and is slidably inserted into the insertion hole 18 of the valve 9 as a switching valve. The spool valve 17 controls the conduction state between the orifice 16 and the high pressure chamber 15. ..

As shown in FIG. 2, the spool valve 17 has a large diameter portion 19, a small diameter portion 20 and a stepped pressure receiving surface 21. The spool valve 17 is fixed to the accumulator piston 22 that absorbs the expansion and contraction of the enclosed oil, and moves together with the accumulator piston 22. The accumulator piston 22 and the high-pressure chamber 15 are ring-shaped and arranged concentrically with respect to the joint shaft.

Reference numeral 23 is a sub-spool valve for preventing the inclination of the accumulator piston 22. The sub-spool valve 23 is slidably inserted into the insertion hole 24 of the valve 9 and the spool valve 17 is attached to the accumulator piston 22. And are fixed in axisymmetric position. The sub-spool valve 23 also has a large diameter portion 2 formed similarly to the spool valve 17.
5, the small diameter portion 26 and the stepped pressure receiving surface 27. The number of sub-spool valves 23 is not limited to one, but two may be provided.

Reference numeral 28 is a cover, 29 and 30 are oil seals, 31 and 32 are needle bearings, 33 is a stopper ring, and 34 is a spline. Next, the operation will be described. As shown in FIG. 3A, at normal temperature, the oil in the high pressure chamber 15 acts on the stepped pressure receiving surface 21 of the spool valve 17, so that the accumulator piston 22
Is urged to the right in FIG. 3 (A). In this normal temperature state, the high pressure chamber 15 and the orifice 16 are electrically connected to each other, the orifice 16 is in an open state, and oil flows as indicated by an arrow A.

In such a state, when a rotation difference occurs between the cam 2 and the rotor 3, the plunger 6 in the discharge stroke is pushed axially by the cam surface 2A of the cam 2. At this time, since the suction / discharge hole 8 communicates with the discharge port 12, the plunger 6 pushes the oil in the plunger chamber 5 from the suction / discharge hole 8 to the discharge port 12 of the valve 9.

The oil pushed out to the discharge port 12 is
It is supplied to the suction passage 11 through the high pressure chamber 15 and the orifice 16. At this time, the hydraulic pressure in the high pressure chamber 15, the discharge port 12 and the plunger chamber 5 rises due to the resistance of the orifice 16, and a reaction force is generated in the plunger 6. A torque is generated by rotating the cam 2 against the plunger reaction force, and the torque is transmitted between the cam 2 and the rotor 3.

Further, when the cam 2 rotates, a suction stroke occurs, and the suction / discharge hole 8 communicates with the suction port 10. Therefore, the oil in the suction passage 11 enters the plunger chamber 5 through the suction port 10 and the suction / discharge hole 8. Inhaled, the plunger 6 returns along the cam surface 2A of the cam 2. When the rotation direction of the rotor 3 is reversed, the cam 2 rotates with the rotor 3,
The protrusion 2B of the cam 2 rotates until it contacts the notch 1A of the housing 1, and then rotates integrally with the housing 1. As a result, a torque characteristic that squares with respect to the differential rotation speed ΔN as shown by B in FIG. 4 is obtained even during forward rotation and reverse rotation.

When the temperature rises, the enclosed oil expands and the accumulator piston 22 gradually moves to the left in FIG. 3, so that the orifice 16 is gradually squeezed. The torque characteristic at this time is the torque characteristic between B and C in FIG. When the temperature becomes high, the accumulator piston 22 moves further leftward as shown in FIG.
The orifice 16 is closed by a spool valve 17. At this time, the torque characteristic is in a locked state as shown in C of FIG.

As described above, in this embodiment, since the brake mechanism is unnecessary, the joint is small and lightweight, and the cost is low. Further, the internal pressure of the joint does not increase, and the pressure resistance of the oil seal may be low. Next, FIGS. 5 and 6 are views showing another embodiment of the present invention. In FIG. 5, reference numeral 41 is a relief spring, and the spring 41 is interposed between the retainer 43 fixed to the spool valve 42 and the accumulator piston 22.

The spool valve 42 is not fixed to the accumulator piston 22.
Is urged by the spring 41 so as to contact the step portion 44. In the normal temperature state, the orifice 16 is in an open state as shown in FIG. 5 (A), and has normal characteristics as shown in D of FIG.

Next, in the high temperature state and when a torque larger than a predetermined value is applied, the once closed orifice 16 moves again to the right of the spool valve 42, and again as shown in FIG. 5 (B). open. That is, in the high temperature state, the accumulator piston 22 compresses the spring 41 and moves the spool valve 42 to the left to close the orifice 16. However, when the torque exceeds a predetermined value, the spool valve 42 has a stepped pressure receiving surface. Since 45 is formed, the spool valve 42 receives a load in the right direction due to the pressure of the high pressure chamber 15, and when the load exceeds the biasing force of the spring 41,
Moving to the right, the orifice 16 reopens. The torque characteristic in this case is shown by E in FIG. 6, and the tight corner braking phenomenon can be prevented. Further, the torque T required and sufficient for running on a rough road can be obtained.

Also in this embodiment, the same effect as in the above embodiment can be obtained.

[0024]

As described above, according to the present invention, since the brake mechanism is unnecessary, it is possible to reduce the size, weight and cost of the joint. Moreover, since the internal pressure of the joint does not increase, the pressure resistance of the oil seal may be low.

[Brief description of drawings]

FIG. 1 is a diagram showing an embodiment of the present invention.

FIG. 2 is a partial perspective view of a spool valve.

FIG. 3 is an explanatory view of the action in a room temperature state and a high temperature state.

FIG. 4 is a graph showing torque characteristics

FIG. 5 is an operation explanatory view showing another embodiment.

FIG. 6 is a graph showing torque characteristics of another embodiment.

[Explanation of symbols]

 1: Housing 1A: Notch 2: Cam 2A: Cam surface 2B: Positioning and torque transmitting projection 3: Rotor 4: Input shaft 5: Plunger chamber 6: Plunger 7: Return spring 8: Suction / discharge hole 9: Valve (valve body) 10: Suction port 11: Suction path 12: Discharge port 13: Protrusion 14: Bearing 15: High pressure chamber 16: Orifice (flow resistance generating means) 17: Spool valve (switching valve) 18: Insertion hole 19: Large diameter part 20: Small diameter part 21: Stepped pressure receiving surface 22: Accumulator piston 23: Sub spool valve 24: Insertion hole 25: Large diameter part 26: Small diameter part 27: Stepped pressure receiving surface 28: Cover 29, 30: Oil seal 31, 32: Needle bearing 33: Stopper ring 34: Spline 41: Spring 42: Spool valve 43: Retainer 44: Stepped portion 45: Stepped pressure receiving surface

Claims (3)

[Claims] 1. A hydraulic pump provided between relatively rotatable input / output shafts and driven by differential rotation of the both shafts, a high pressure chamber for collecting discharge oil of the hydraulic pump, and a joint from the high pressure chamber. A hydraulic power transmission joint, comprising: a flow resistance generating means provided at an outlet to the low pressure chamber; and an accumulator mechanism that absorbs expansion and contraction of the enclosed oil, and transmitting torque according to a rotational speed difference between the two shafts, In addition to providing one orifice as a flow resistance generating means, a spool-shaped switching valve for controlling the conduction state between the orifice and the high pressure chamber is provided, and when the temperature exceeds a predetermined value, the switching is performed by the displacement of the accumulator piston. A hydraulic power transmission joint characterized in that the valve is switched from an open state to a closed state. 2. A stepped pressure-receiving surface for moving the switching valve in the direction in which the orifice opens in response to the pressure of the discharged oil is provided in the switching valve, and the accumulator piston and the switching valve are connected by a spring to discharge the discharged oil. The hydraulic power transmission joint according to claim 1, wherein the switching valve moves in a direction to open the orifice when the pressure exceeds a predetermined value. 3. The accumulator piston and the high pressure chamber are ring-shaped and arranged concentrically with respect to a joint shaft, and the switching valve is provided away from the shaft core,
A sub-spool valve having the same stepped pressure receiving surface as the switching valve is provided at an axially symmetrical position with respect to the switching valve,
The hydraulic power transmission coupling according to claim 1, wherein the sub spool valve is connected to the accumulator piston.