JP2501927B2 - Hydraulic power transmission coupling - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a hydraulic power transmission joint used for distributing a driving force of a vehicle.

[Prior Art] In the Japanese Patent Application No. 63-125959, the present applicant has proposed a spool that is stored so as to continuously change the opening area of the discharge passage,
A hydraulic power transmission joint including a piston that moves by the expansion of oil due to a temperature rise and a pull rod that is fixed to the piston and has an engaging portion that penetrates the spool and can press the spool at the end is proposed. ing.

Further, in the Japanese Patent Application No. 63-311531, the applicant has an orifice in a main passage that connects a fluid discharge passage and a suction passage, and when the discharge passage side reaches a predetermined discharge pressure, the applicant resists a spring. We have proposed a hydraulic power transmission joint that includes a moving orifice valve and a needle valve that closes the orifice when the orifice valve moves.

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

In FIG. 7, A is a lock setting torque at which the joint locks, B is a torque generated when a tight corner is entered in a locked state, and C is a differential rotation speed generated at a tight corner without a lock mechanism. , D shows the torque at which the temperature rise during continuous operation becomes the allowable limit, and E shows the torque when traveling on a rough road.

[Problems to be Solved by the Invention] However, in such a conventional hydraulic power transmission joint, in the former case, it takes time for the temperature of the joint to decrease, so that the joint is temporarily broken due to traveling on a bad road or the like. When locked, the lock is not released easily, and when traveling on a paved road in such a state, there is a problem that a tight corner braking phenomenon occurs and an excessive torque is generated in the drive system to damage the drive system.

As a countermeasure, there is a problem that the cost increases if the design strength of the drive system is increased.

In the latter case, if the torque to lock is set low, the differential rotation speed to lock becomes low, and the joint locks when turning at a tight corner at high speed, causing not only the tight corner booming phenomenon but also the vehicle. There is a risk of instability, and like the former, there is a risk of damage to the drive system.

If the torque to be locked is set to be high in order to avoid such a problem, there is a problem that the temperature of the joint may abnormally rise depending on the road surface condition even when the lock is desired.

The present invention has been made in view of the above conventional problems, and it is possible to improve running performance on a bad road and surely prevent a temperature rise of a joint, and moreover, tight corner braking on a paved road. It is an object of the present invention to provide a hydraulic power transmission joint that can reduce the cost by reducing the design strength of the drive system while suppressing the phenomenon to a level at which there is no problem.

[Means for Solving the Problems] In order to achieve the above object, the present invention provides a hydraulic pump driven by a rotational speed difference between first and second rotating members that are relatively rotatable, and a hydraulic pump of the hydraulic pump. In a hydraulic power transmission joint in which means for generating flow resistance is provided in the discharge passage, and the transfer torque between the first and second rotating members is controlled by the flow resistance, the discharge fluid is collected in one collecting chamber. A collecting means and a closing means for closing the orifice provided at the outlet of the collecting chamber when the temperature of the joint exceeds a predetermined value, and when the pressure of the collecting chamber exceeds a predetermined value, A limit torque at which the temperature rise of the joint reaches an allowable limit when the vehicle is continuously driven under the condition that the relief means for escaping oil is provided and the differential rotation speed and the transmission torque of the joint are constant at the set value of the relief means. Equivalent to Greater than the force, and,
The pressure is set to be smaller than the pressure generated when the pavement is turned at the minimum turning radius when the joint is in the locked state.

[Operation] In the present invention, the orifice closing means for locking the joint when the temperature of the joint exceeds a predetermined value is provided, and the torque applied to the joint is set to a level at which the tight corner braking phenomenon does not pose a problem. Since a relief mechanism is provided to limit the temperature of the joint to below the allowable limit under all road surface conditions, the tight corner braking phenomenon can be prevented even if the vehicle enters the paved road while being locked due to bad road driving. It can be suppressed to a level at which there is no practical problem.

Further, since an excessive torque is not applied to the drive system, the design strength of the drive system can be reduced and the cost can be reduced.

[Embodiment] An embodiment of the present invention will be described below with reference to the drawings.

 1 to 6 are views showing an embodiment of the present invention.

First, the configuration will be described. In FIGS. 1 to 3,
Reference numeral 1 denotes a cam having a cam surface 2 formed on an inner surface thereof. The cam 1 is connected to an output shaft or an input shaft and rotates integrally with the output shaft or the input shaft. The cam 1 is fixed to the cam housing 3, and the cam housing 3 rotates integrally with the cam 1.

4 is a rotor rotatably housed in the cam housing 3, and the rotor 4 is connected to an input shaft or an output shaft,
Rotates integrally with the input shaft or 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 slidably accommodated in the plunger chamber 5 via return springs 7.

Reference numeral 31 is a rotary valve provided on the outer peripheral portion of the rotor 4, and the rotary valve 31 has a positioning projection 33 that engages with a notch 32 formed in the cam housing 3, and also the suction valve formed in the rotor 4. It has an intake port 35 that acts as an intake valve depending on the positional relationship with the hole 34. Also,
A discharge passage 36 communicating with the plunger chamber 5 is formed in the rotor 4, and a discharge valve 37 (collecting means) is interposed in the discharge passage 36 by a spring 38.

41 is a gathering chamber, and the gathering chamber 41 is a discharge valve 37 and a discharge passage.
It communicates with the plunger chamber 5 via 36. Reference numeral 42 denotes a plug member inserted into the rotor 4, and an orifice 43 is formed in the plug member 42, and the collecting chamber 41 and the low pressure chamber 44 communicate with each other through the orifice 43.

45 is a needle valve as a closing means and a relief means, and the needle valve 45 has a retainer 46 at its rear part.
The head is held in the 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 equal to or lower than the transformation temperature of the shape memory alloy, the elastic force of the shape memory alloy is very small, so that the spring force of the spring 48 is very small.

Therefore, the needle valve 45 loses the fluid pressure of the oil discharged from the orifice 43 and moves to the right in the figure, and the orifice 43 is open.

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

In this state, when the hydraulic 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 43 is opened again.

Here, the relief set value is larger than the pressure corresponding to the limit torque at which the temperature rise of the joint reaches the allowable limit when the vehicle continuously runs under the condition that the differential rotation speed and the transmission torque of the joint are constant. And, when the joint is in the locked state, it is set to a value smaller than the pressure generated when the pavement is turned at the minimum turning radius.

Further, an oil groove 21 is formed in the rotor 4, and the orifice 43
The oil that has passed through the low pressure chamber 44,
Oil groove 21, suction port 35 of rotary valve 31, suction hole 34
After that, it is sucked into the plunger chamber 5. 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 the differential rotation changes, the rotary valve 31 moves with the rotor 4. It rotates and rotates until the protrusion 33 hits the notch 32, and then rotates integrally with the cam housing 3.

Reference numeral 22 is a frust block that rotates integrally with the cam housing 3, and 24 is an accumulator piston that rotates integrally with the thrust block 22.
A spring 50 is interposed between the 24 and the retainer 49.

Reference numeral 25 is an oil seal, 26 is a stop ring, 28 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 operation will be described.

When there is no rotation difference between the cam 1 and the rotor 4,
The plunger 6 does not operate and no torque is transmitted. At this time, the plunger 6 has the return spring 7
To the cam surface 2.

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

Therefore, the plunger 6 pushes the oil in the plunger chamber 5 from the discharge passage 36 to the collecting chamber 41 via the discharge valve 37, and the suction hole 34 is forcibly closed by the rotary valve 31 (Fig. 4, reference).

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

Further, 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 from the oil groove 21, the suction port 35 of the rotary valve 31 through the suction hole 34, and the cam. Return along the cam surface 2 of 1.
Thus, the suction hole 34 is forcibly opened by the rotary valve 31 (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 moves to the right in the figure by the oil flow from the orifice 43. Have moved to. The transfer torque characteristic when this temperature is below a predetermined value is shown in F of FIG.

When the temperature of the joint exceeds a predetermined value, the spring 48 deforms and the needle valve 45 moves leftward in the figure to close the orifice 43, as shown in FIG. 5 (B). Thus, the locked state is entered.

When the hydraulic 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 to move the orifice 43 again, as shown in FIG. 5 (C). open. The transmission torque characteristic at this time is shown in FIG. 6G. Further, in this state, the torque generated at the tight corner is indicated by H.

In this way, the temperature of the joint can be kept below the allowable limit under all road surface conditions, and the tight corner braking phenomenon is a practical problem even if it enters the paved road while being locked due to bad road driving. It can be suppressed to a non-existent level.

Further, since an excessive torque is not applied to the drive system, the design strength of the drive system can be reduced and the cost can be reduced.

[Effects of the Invention] As described above, according to the present invention, the orifice closing means for locking the joint when the temperature of the joint exceeds a predetermined value is provided, and the torque applied to the joint is tight. Since the relief mechanism is provided to limit the level of corner braking to a level that does not pose a problem, the temperature of the joint can be kept below the allowable limit under all road surface conditions. Even if it enters, the tight corner braking phenomenon can be suppressed to a level at which there is no practical problem.

Further, since an excessive torque is not applied to the drive system, the design strength of the drive system can be reduced and the cost can be reduced.

[Brief description of drawings]

FIG. 1 is a view showing an embodiment of the present invention, FIG. 2 is a cross-sectional view thereof, FIG. 3 is an explanatory view of a main part of a rotary valve, FIG. 4 is a view showing opening / closing timings of an intake valve and a discharge valve, FIGS. 5A to 5C are explanatory diagrams of the operation, FIG. 6 is a diagram showing torque characteristics of the present invention, and FIG. 7 is a diagram showing torque characteristics of a 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 …… Projection, 34 …… Suction hole, 35 …… Suction port, 36 …… Discharge Road,
37 ... Discharge valve, 38 ... Spring, 39 ... Blind plug, 41 ... Collecting chamber, 42 ... Plug member, 43 ... Orifice, 44 ... Low pressure chamber, 45 ... Needle valve, 46, 49 ...
Retainer, 47 ... Opening, 48 ... Spring, 50 ... Spring.

Claims (2)

(57) [Claims] 1. A hydraulic pump driven by a rotational speed difference between relatively rotatable first and second rotating members, and means for generating flow resistance in a discharge passage of the hydraulic pump, wherein the flow resistance In the hydraulic power transmission joint in which the transmission torque between the first and second rotating members is controlled, a collecting means for collecting the discharge fluid in one collecting chamber and a case where the temperature of the joint exceeds a predetermined value The closing means for closing the orifice provided at the outlet of the collecting chamber is provided, and the relief means for allowing the oil in the collecting chamber to escape when the pressure in the collecting chamber exceeds a predetermined value is provided. When the vehicle continuously runs under the condition that the differential rotation speed and the transmission torque are constant, the temperature rise of the joint is higher than the pressure corresponding to the limit torque that reaches the allowable limit, and
A hydraulic power transmission joint, wherein when the joint is in a locked state, the pressure is set to be smaller than a pressure generated when the pavement is turned at a minimum turning radius. 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.