JPH03213726A - Hydraulic power transmission coupling - Google Patents

Abstract

PURPOSE:To suppress the temperature of a coupling to below the allowable limit on any road surface by allowing the coupling to detect the pressure in a collecting chamber proportional to transmission torque so as to close variable orifice mechanism automatically, thereby placing the coupling in the locked state. CONSTITUTION:When rotational difference is generated between a cam 1 and a rotor 4, a plunger 6 in the delivery stroke is pushed in axially by the cam face 2 of the cam 1. The plunger 6 pushes oil in a plunger chamber 5 out into a collecting chamber 41 from a delivery passage 36 through a delivery valve 37, as well as a suction chamber 34 is forcibly closed by a rotary valve 31. The oil pushed out into the collecting chamber is fed into a low pressure chamber 51 through an orifice 44. The oil pressure in the collecting chamber 41 and plunger chamber 5 rises to generate the reaction of the plunger 6. Against this reaction, torque is transmitted between the cam 1 and the rotor 4, and when the cam 1 is rotated, the plunger 6 enters into the suction stroke, so that the oil in the low pressure chamber 51 is sucked into the plunger chamber 5 and returned to the cam face 2.

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 that can press 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 Figure 7, A is the lock setting torque that causes the joint to lock, B is the generated torque when entering a tight corner with the joint in the locked state, and C is the differential rotation that occurs when entering a tight corner without the lock mechanism. D represents the torque at which the temperature rise reaches the permissible limit during continuous operation, and E represents the torque when driving on rough roads.

[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 become damaged due to driving on rough roads, etc. Once locked, it is difficult to release the lock, and when driving on paved roads in such conditions, tight corner braking occurs, and excessive torque is generated in the drive system, causing damage to the drive system.

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 lock setting 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 can improve running performance on rough roads and reliably prevent the temperature rise of the joint, and also solves the problem of tight corner play kink on paved roads. The purpose of the present invention is to provide a hydraulic power transmission joint that can reduce the design strength of the drive system to a level that does not require any damage and 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, the discharge path is provided with a collecting means for collecting the discharged fluid into one collecting chamber, and the pressure in the collecting chamber exceeds the first set value. A variable orifice mechanism is provided in the outlet path of the collecting chamber, and a relief means is provided to release oil from the collecting chamber when a higher second set value is exceeded; is smaller than the pressure corresponding to the torque at which the temperature rise of the joint reaches the permissible limit when the vehicle runs continuously under the condition that the differential rotation speed and transmission torque of the joint are constant, and the second set value is The pressure is set to be larger than the first set value and smaller than the pressure generated when turning on a paved road with a small turning radius when the joint is in the locked state.

[Function] In the present invention, when a high differential rotation occurs in the joint due to driving on a rough road, etc., the pressure in the collection chamber proportional to the transmission torque of the joint is detected, and the variable orifice mechanism is automatically activated. The joint is locked by closing it.

This lock setting torque (corresponds to the first setting value)
The torque is such that the temperature of the joint does not exceed the allowable limit even when driving continuously in a differential state, so the temperature of the joint can be kept below the allowable limit on any road surface.

In addition, by making this setting, the locking differential rotation speed is lowered, so the joint can be reliably locked when driving on rough roads where the differential rotation speed between the front and rear wheels is too high and drivability deteriorates. This makes it possible to improve drivability on rough roads.

On the other hand, if the setting is made as described above, a problem arises in that the joint is likely to lock even when turning on a paved road. If the torque exceeds the set value (corresponding to the setting value of 2), we have installed a function that limits the torque by allowing the oil in the collecting room to escape and allowing the differential to operate again. Even if the locking mechanism is activated on a paved road, tight corners can be avoided. Braking phenomena can be suppressed to a level that poses no problem in practical use.

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] 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 cam housing 3; It has a suction port 35 that functions as a suction valve depending on its positional relationship with the hole 34. Further, 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 this discharge passage 36 by a spring 38.

Reference numeral 41 denotes a collecting chamber that communicates with the discharge passage 36 via the discharge valve 37, and the collecting chamber 41 is connected to the plug member 4 provided in the rotor 4.
An orifice valve 45 having an orifice 44 is movably stored in the storage chamber 43 by a spring 46 for setting a lock pressure.

A needle valve 48 that closes the orifice 44 by a spring 47 for setting relief pressure is movably housed in the orifice valve 45 . The storage chamber 43 communicates with a low pressure chamber 51 via an opening 50 in the retainer 49 .

If the pressure in the gathering chamber 41 is less than the first set value, the orifice valve 45 will not move and the orifice 44 will be in the open state. When the pressure in the collecting chamber 41 is greater than or equal to the first set value and less than the second set value, the orifice valve 45 moves and abuts the needle valve 48, closing the orifice 44. When the pressure in the gathering chamber 41 becomes equal to or higher than the second set value, the needle valve 48 moves and the orifice 44 is opened again. Here, the first set value is a value smaller than the pressure corresponding to the torque at which the temperature rise of the joint reaches the allowable limit when the vehicle runs continuously under conditions where the differential rotation of the joint and the transmitted torque are constant. and the second set value is set to a value that is larger than the first set value and smaller than the pressure that occurs when turning on a paved road with a small turning radius when the joint is in the locked state. Ru.

Further, an oil groove 21 is formed in the rotor 4, and an orifice 4
4, the oil passes through the low pressure chamber 5 as shown by arrow A.
1. Oil groove 21, suction port 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 53 is interposed between the accumulator piston 24 and the retainer 52;

In addition, 25 is an oil seal, 26 is a stop ring, 2
8 is a mounting hole for the input/output shaft.

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 51 through the orifice 44. At this time, orifice 4
4 increases the oil pressure in the gathering chamber 41 and the plunger chamber 5, 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 51 is sucked into the plunger chamber 5 from the oil groove 21 and the suction port 35 of the rotary valve 31 through the suction hole 34. 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 pressure in the gathering chamber 41 is less than the first set value, the orifice valve 45
does not move and the orifice 44 becomes open. The transmitted torque characteristic in this case is shown in F in FIG.

When the pressure in the gathering chamber 41 is greater than or equal to the first set value and less than the second set value, the orifice valve 45 moves to the right in the figure, and the orifice 44 is closed by the needle valve 48 and enters the locked state ( (See Figure 5(B)). The torque at this time is shown in G in FIG.

This lock setting torque (corresponds to the first setting value)
The torque is such that the temperature of the joint does not exceed the allowable limit even when driving continuously in a differential state, so the temperature of the joint can be kept below the allowable limit on any road surface.

In addition, this setting lowers the differential rotation speed at which the lock is applied, so the joint can be reliably locked when driving on rough roads where the differential rotation between the front and rear wheels is too high and drivability deteriorates. This makes it possible to improve drivability on rough roads.

When the pressure in the gathering chamber 41 becomes equal to or higher than the second set value, the needle valve 45 moves to the right in the figure, and the orifice 44 becomes open again (see FIG. 5(C)). The transmitted torque characteristic in this state is shown by H in FIG. 6, and the generated torque at a tight corner is shown by I in FIG.

Therefore, if the setting is made as described above, the differential rotation speed at which the locking occurs will also be lower, which causes the problem that the joint is more likely to lock when turning on a paved road.
If the torque applied to the joint in the locked state exceeds a predetermined value (corresponding to the second set value), the gathering chamber 41
Since the torque is limited by letting the oil inside, even if the joint locks up on a paved road, the tight corner braking phenomenon can be suppressed to a level that does not pose a 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.

[Effects of the Invention] As explained above, according to the present invention, the pressure in the gathering chamber that is proportional to the transmission torque of the joint is detected and the variable orifice mechanism is automatically closed, thereby locking the joint. This lock setting torque (corresponding to the first setting value) is set to a torque that does not cause the temperature of the joint to exceed the allowable limit even when running continuously in a differential state.
The temperature of the joint can be kept below the permissible limit on any road surface.

In addition, this setting lowers the differential rotation speed at which the lock is applied, so the joint can be reliably locked when driving on rough roads where the differential rotation between the front and rear wheels is too high and drivability deteriorates. This makes it possible to improve drivability on rough roads.

In addition, if the torque applied to the joint in the locked state exceeds a predetermined value (corresponding to the second set value), the oil in the collecting chamber is released to enable differential operation again and limit the torque. Even if the locking mechanism operates on a paved road, the tight corner flaking phenomenon can be suppressed to a level that poses no practical problem, and the design strength of the drive system can be lowered, resulting in cost reduction.

[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 part of a rotary valve, Fig. 4 is a diagram showing the opening/closing timing of the suction valve and the discharge valve, 5(A-C) are diagrams 1 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, ■...Cam, 2...Cam surface, 3...Cam housing, 4...Rotor, butt...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...stopper , 41... Gathering chamber, 42... Plug member, 43... Storage chamber, 44... Orifice, 45... Orifice valve, 46.47... Spring, 48... Needle valve, 49.52...Retainer, 50...Opening, 51...Low pressure chamber, 53...Spring.

Claims (1)

[Scope of Claims] A hydraulic pump driven by a difference in rotational speed between first and second rotary members that are relatively rotatable, and means for generating flow resistance in a discharge path of the hydraulic pump, the flow resistance being controlled by the flow resistance. In the hydraulic power transmission joint in which the transmission torque between the first and second rotating members is controlled by A variable orifice mechanism that closes the orifice when a set value is exceeded is provided in the exit path of the collecting chamber, and a relief means is provided that releases oil from the collecting chamber when a second higher set value is exceeded, The first set value is set to be smaller than the pressure corresponding to the 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 The second setting value is set to be larger than the first setting value and smaller than the pressure generated when turning on a paved road with a small turning radius when the joint is in a locked state. Hydraulic power transmission joint.