JPH03213727A - Hydraulic power transmission coupling - Google Patents

Abstract

PURPOSE:To suppress the temperature of a coupling to below the allowed limit in any road surface state by providing a closing means for placing the coupling in the locked state in case of the temperature of the coupling exceeding the specified value, as well as providing a relief means for regulating torque. CONSTITUTION:When the temperature of a coupling is lower than the deformation temperature of a spring 48, a needle valve 45 moves to the right by oil flow from an orifice 43. On the other hand, when the temperature of the coupling exceeds the specified value, the spring 48 moves to the left to close the orifice 43 and enter into the locked state. When the oil pressure of the collecting chamber 41 exceeds the set pressure determined by the spring 48 and orifice diameter, the valve 45 moves to the right to reopen the orifice 43. The temperature of the coupling can be thereby suppressed to below the allowed limit in any road surface state, thereby suppressing to the level of not starting a tight corner braking phenomenon even if entering on a paved road in the locked state left from bad road running.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a hydraulic power transmission joint used for distributing driving force in a vehicle.

[Prior Art] In Japanese Patent Application No. 63-125959, the present applicant discloses a spool that is housed so as to continuously change the opening area of a discharge passage, a piston that moves due to the expansion of oil due to a rise in temperature,
a pull rod that is fixed to the piston, passes through the spool, and has an engaging portion at an end capable of suppressing the spool;
We are proposing a hydraulic power transmission joint equipped with

Furthermore, in Japanese Patent Application No. 63-311531, the present applicant has proposed that an orifice is provided in a main passage that communicates a fluid discharge passage and a suction passage, and that when the discharge passage side reaches a predetermined discharge pressure, a spring is applied. A hydraulic power transmission coupling is proposed that includes a moving orifice valve and a needle valve that closes the orifice when the orifice valve moves.

Next, FIG. 7 shows the torque characteristics of these conventional examples.

In Fig. 7, A is the lock setting torque at which the joint locks, B is the generated torque when entering a tight corner in the locked state, and C is the differential rotation speed that would occur when entering a tight corner without a locking mechanism. , D indicate the torque at which the temperature rise reaches the permissible limit during continuous operation, and E indicates the torque when driving on a rough road.

[Problems to be Solved by the Invention] °However, in the former case, with such conventional hydraulic power transmission joints, it takes time for the temperature of the joint to drop, so the joint may be temporarily disconnected due to driving on rough roads, etc. If the vehicle locks, the vehicle will not be unlocked, and driving on paved roads in such conditions will cause tight corner braking, and excessive torque will be generated in the drive system, causing damage to the drive system. there were.

As a countermeasure to this problem, there was also the problem that increasing the design strength of the drive system would increase costs.

In addition, in the latter case, if the locking torque is set low, the locking differential rotation speed will also be low, and when turning a tight corner at high speed, the joint will lock, not only causing tight corner braking but also causing damage to the vehicle. There was a risk that the system would become unstable, and as with the former, there was a risk of damage to the drive system.

If the locking torque is set high to avoid such problems, the joint may not lock even when desired depending on the road surface conditions, and the temperature of the joint may rise abnormally.

The present invention has been made in view of these conventional problems, and is capable of improving running performance on rough roads, reliably preventing a rise in temperature of the joint, and preventing tight corner play kinks on paved roads. The purpose of this invention is to provide a hydraulic power transmission joint that can suppress the phenomenon to a non-problematic level and reduce the design strength of the drive system to reduce costs.

[Means for Solving the Problems] In order to achieve the above object, the present invention provides a relatively rotatable first . A hydraulic pump driven by a difference in rotational speed between the second rotating members, and means for generating flow resistance in a discharge path of the hydraulic pump, the flow resistance causing the first. In a hydraulic power transmission joint in which the transmission torque between the second rotating members is controlled, there is a collecting means for collecting the discharged fluid into one collecting chamber, and an outlet of the collecting chamber when the temperature of the joint exceeds a predetermined value. A closing means is provided to close the orifice provided in the joint, and a relief means is provided to release the oil in the gathering chamber when the pressure in the gathering chamber exceeds a predetermined value, and the setting value of the relief means is set by the differential rotation of the joint. When the vehicle runs continuously under conditions where the number and transmitted torque are constant, the temperature rise of the joint is greater than the pressure corresponding to the limit torque at which the temperature rise reaches the permissible limit, and
When the joint is in a locked state, the pressure is set to be lower than that generated when turning on a paved road with a small turning radius.

[Function] In the present invention, an orifice closing means is provided that locks the joint when the temperature of the joint exceeds a predetermined value, and the torque applied to the joint is reduced to a level where tight corner braking phenomenon does not become a problem. By providing a limiting relief means, it is possible to keep the temperature of the joint below the permissible limit under all road conditions, and even if the joint is locked due to driving on rough roads and enters a paved road, tight corner braking will not occur. It can be suppressed to a level that does not cause any practical problems.

Also, since excessive torque is not applied to the drive system,
The design strength of the drive system can be lowered and costs can be reduced.

[Example code] Embodiments of the present invention will be described below based on the drawings.

1 to 6 are diagrams showing one embodiment of the present invention.

First, to explain the configuration, in Figures 1 to 3, 1
1 is a cam with a cam surface 2 formed on its inner surface, and the cam 1 is connected to an output shaft or an input shaft, and rotates integrally with the output shaft or input shaft. Further, the cam 1 is fixed to a cam housing 3, and the cam housing 3 rotates integrally with the cam 1.

A rotor 4 is rotatably housed in the cam housing 3. The rotor 4 is connected to the input shaft or the output shaft, and rotates together with the input shaft or the output shaft.

A plurality of plunger chambers 5 are formed in the rotor 4 in the axial direction, and a plurality of plungers 6 are formed in the plunger chamber 5.
is slidably housed via a return spring 7.

31 is a rotary valve provided on the outer periphery of the rotor 4, and the rotary valve 31 has a positioning protrusion 33 that engages with a notch 32 formed in the housing 3 of the cam no. It has a suction boat 35 that functions as a suction valve depending on its positional relationship with the suction hole 34. Further, a discharge passage 36 communicating with the plunger chamber 5 is formed in the rotor 4, and this discharge passage 36 has a discharge valve 37 (
A gathering means) is interposed by a spring 38.

41 is a gathering chamber, and the gathering chamber 41 communicates with the plunger chamber 5 via the discharge valve 37 and the discharge passage 36. 4
2 is a plug member inserted into the rotor 4, an orifice 43 is formed in the plug member 42, and the orifice 4
The gathering chamber 41 and the low pressure chamber 44 are in communication with each other via 3.

Reference numeral 45 designates a needle valve as a closing means and a relief means, and the needle valve 45 has its rear portion held by a retainer 46 and its head portion held in an opening 47 of the plug member 42 . A spring 48 made of a shape memory alloy is interposed between the retainer 46 and the needle valve 45.

When the temperature is below the transformation temperature of the shape memory alloy, the elastic modulus of the shape memory alloy is very small, so the spring force of the spring 48 is very small.

Therefore, the needle valve 45 is moved to the right in the figure by the fluid pressure of the oil discharged from the orifice 43, and the orifice 43 is in an open state.

When the temperature exceeds the transformation temperature of the shape memory alloy, the spring force of the spring 48 becomes stronger and the needle valve 45 closes the orifice 43, locking the joint.

In this state, when the oil pressure in the collecting chamber 41 exceeds the relief pressure (set value) determined by the spring 48 and the orifice diameter, the needle valve 45 moves to the right in the figure, and the orifice 4
3 becomes open again.

Here, the relief setting value is greater than the pressure corresponding to the limit torque at which the temperature rise of the joint reaches the allowable limit when the vehicle runs continuously under conditions where the differential rotation speed and transmission torque of the joint are constant. , and is set to a value smaller than the pressure generated when turning on a paved road with a small turning radius when the joint is in a locked state.

Further, an oil groove 21 is formed in the rotor 4, and an orifice 4
3, the oil passes through the low pressure chamber 4 as shown by arrow A.
4. Oil groove 21, suction boat 35 of rotary valve 31
, is sucked into the plunger chamber 5 through the suction hole 34. The friction torque between the rotor 4 and the rotary valve 31 is set to be larger than the friction torque between the cam housing 3 and the rotary valve 31, and when the direction of differential rotation changes, the rotary valve 31 moves along with the rotor 4. After rotating until the protrusion 33 hits the notch 32, it rotates integrally with the cam housing 3.

22 is a thrust block that rotates integrally with the cam housing 3; 24 is an accumulator piston that rotates integrally with the thrust block 22; a spring 50 is interposed between the accumulator piston 24 and the retainer 49;

In addition, 25 is an oil seal, 26 is a stop ring, 2
8 is a mounting hole for the input/output shaft, and 39 is a blind plug provided at the bottom of the plunger chamber 5.

Next, the effect will be explained.

When there is no difference in rotation between the cam 1 and the rotor 4, the plunger 6 does not operate and no torque is transmitted. Note that at this time, the plunger 6 is pressed against the cam surface 2 by the return spring 7.

Next, when a rotation difference occurs between the cam 1 and the rotor 4, the plunger 6, which is in the discharge stroke, is pushed in the axial direction by the cam surface 2 of the cam 1.

Therefore, the plunger 6 pushes out the oil in the plunger chamber 5 from the discharge passage 36 through the discharge valve 37 to the collective chamber 41, and the suction hole 34 is forcibly closed by the rotary valve 31 (see FIG. reference).

The oil pushed out into the gathering chamber 41 is supplied to the low pressure chamber 44 through the orifice 43. At this time, orifice 4
Due to the resistance 3, the hydraulic pressure in the collecting chamber 41 and the plunger chamber 5 increases, and a reaction force is generated in the plunger 6. Torque is generated by rotating the cam 1 against this plunger reaction force, and the torque is transmitted between the cam 1 and the rotor 4.

Furthermore, when the cam 1 rotates, the plunger 6 enters the suction stroke, and the oil in the low pressure chamber 44 is sucked into the plunger chamber 5 through the suction hole 34 from the oil groove 21 and the suction port 35 of the rotary valve 31. Return along cam surface 2 of cam 1. In this way, the suction hole 34 is connected to the rotary valve 3
1, the valve is forcibly opened (see Fig. 4).

Here, as shown in FIG. 5(A), when the temperature of the joint is lower than a predetermined temperature, that is, the deformation temperature of the spring 48, the needle valve 45 is moved in the right direction in the figure by the flow of oil from the orifice 43. is moving to. The transmission torque characteristic when this temperature is below a predetermined value is shown in F in FIG.

When the temperature of the joint exceeds a predetermined value, the spring 48 is deformed and the two dollar valve 45 moves to the left in the figure to close the orifice 43, as shown in FIG. 5(B). In this way, it enters the locked state.

When the oil pressure in the collecting chamber 41 exceeds the relief pressure (set value) determined by the spring 48 and the orifice diameter, the needle valve 45 moves to the right in the figure and closes the orifice 43 again, as shown in FIG. 5(C). open. The transmitted torque characteristics at this time are shown in FIG. 6G.

Furthermore, in this state, H indicates the torque generated during a tight corner.

In this way, the temperature of the joint can be kept below the permissible limit under all road conditions, and even if the joint is locked due to driving on a rough road and enters a paved road, the tight corner braking phenomenon can be prevented from becoming a practical problem. It can be suppressed to a level of zero.

Also, since excessive torque is not applied to the drive system,
The design strength of the drive system can be lowered and costs can be reduced.

[Effects of the Invention] As described above, according to the present invention, an orifice closing means is provided that locks the joint when the temperature of the joint exceeds a predetermined value, and the torque applied to the joint is tightened. By providing a relief means that limits the corner braking phenomenon to a level where it does not become a problem, the temperature of the joint can be kept below the permissible limit under all road surface conditions, and moreover, it is possible to keep the temperature of the joint below the permissible limit under all road conditions. Even when entering a corner, the tight corner braking phenomenon can be suppressed to a level that poses no practical problem.

Also, since excessive torque is not applied to the drive system,
The design strength of the drive system can be lowered and costs can be reduced.

[Brief explanation of drawings]

Fig. 1 is a diagram showing an embodiment of the present invention, Fig. 2 is a sectional view thereof, Fig. 3 is an explanatory diagram of the main parts of a rotary valve, Fig. 4 is a diagram showing the opening/closing timing of the suction valve and discharge valve, 5(A-C) are diagrams for explaining the operation, FIG. 6 is a diagram showing the torque characteristics of the present invention, and FIG. 7 is a diagram showing the torque characteristics of the conventional example. In the figure, 1... cam, 2... cam surface, 3... cam housing, 4... rotor, 5... plunger chamber, 6... plunger 7... return spring, 21... Oil groove, 22... Thrust block, 24... Accumulator piston, 25... Oil seal, 26... Stop ring, 28... Mounting hole, 31... Rotary valve, 32 ...notch, 33...protrusion, 34...suction hole, 35...suction boat, 36...discharge path, 37...discharge valve, 38...spring, 39... Mekura plug, 41... Collection chamber, 42... Plug member, 43... Orifice, 44... Low pressure chamber, 5... Needle valve, 6.49... Retainer, 7... Opening part , 8...Spring, 0...Spring.

Claims (2)

[Claims] (1) A hydraulic pump driven by a difference in rotational speed between first and second rotating members that are relatively rotatable, and a means for generating flow resistance in a discharge path of the hydraulic pump, the hydraulic pump being driven by a rotational speed difference between first and second rotating members that are relatively rotatable; 1. In a hydraulic power transmission joint in which the transmission torque between the second rotating member is controlled, there is a collecting means that collects the discharged fluid into one collecting chamber, and a collecting means that collects the discharge fluid in one collecting chamber when the temperature of the joint exceeds a predetermined value. A closing means is provided to close the orifice provided at the outlet of the joint, and a relief means is provided to release the oil in the gathering chamber when the pressure in the gathering chamber exceeds a predetermined value. When the vehicle runs continuously under conditions where the dynamic rotational speed and transmitted torque are constant, the temperature rise of the joint is greater than the pressure corresponding to the limit torque at which the temperature rise reaches the permissible limit, and
A hydraulic power transmission joint, characterized in that the pressure is set to be lower than the pressure generated when turning on a paved road with a small turning radius when the joint is in a locked state. (2) The hydraulic power transmission joint according to claim 1, wherein the closing means for closing the orifice and the relief means are made of the same member.