JPH0579520A - Hydraulic power transmission coupling - Google Patents

Abstract

PURPOSE:To provide a coupling capable of setting a free condition not to transmit torque between an input shaft and an output shaft at an optional time, in a hydraulic power transmission coupling to control torque transmission between relatively rotatable input shaft and output shaft according to rotating speed difference between the input and output shafts. CONSTITUTION:A hydraulic pump to operate according to rotating speed difference is provided between an input shaft and an output shaft relatively rotatable. A high pressure chamber 46 to collect liquid pressure from the hydraulic pump is provided. Further, a closing means to close an orifice 54 connected to the high pressure chamber 46 when the liquid pressure in the high pressure chamber 46 is over a prescribed value, and a relief means to lose the pressure in the high pressure chamber 46 by an external signal are provided.

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 coupling which obtains torque transmission characteristics with respect to a rotational speed difference between two power rotary shafts in accordance with the diameter of an orifice provided inside.

[0002]

2. Description of the Related Art Conventionally, an example of such a hydraulic power transmission joint is disclosed in Japanese Patent Application No. 63-311531. This hydraulic power transmission joint includes a hydraulic pump for flowing an amount of fluid corresponding to a rotational speed difference between the input and output shafts, and an orifice for generating a flow resistance of the fluid, between the input and output shafts that are relatively rotatable. And the torque is transmitted between the input and output shafts by the reaction force against the flow resistance. Further, when the difference in rotational speed increases and the transmission torque reaches a predetermined value, the discharge path of the hydraulic pump is closed to lock the input and output shafts to prevent the vehicle from running on sandy or snowy roads. It has functions such as improving.

[0003]

However, when such a conventional hydraulic power transmission joint is applied to the control of torque transmission between the front and rear wheels and the left and right wheels together with the differential mechanism of an automobile, it travels on sandy land or the like. In order to prevent only the drive wheels from slipping when driving, if the lock point is set low in advance so that the locked state will occur quickly, the joint will be installed when the vehicle turns at a tight corner at high speed. There was a risk of locking up too quickly, causing a so-called tight braking phenomenon, which could lead to instability in driving and damage to the drive system.

Further, in order to prevent such a problem, if the lock point is set high in order to delay the occurrence of the locked state, on the contrary, there is a problem that a problem occurs when traveling on a road surface such as the above sandy land. It was The present invention has been made in view of the above-mentioned conventional technical problems, and hydraulic power that can control switching between normal torque transmission, locked state, and free state according to the running state of the vehicle. An object is to provide a transmission joint.

[0005]

In order to achieve such an object, the present invention provides a hydraulic pump which is provided between input / output shafts which can rotate relative to each other, and which is driven by a rotational speed difference between these shafts, and In a hydraulic power transmission joint having a high-pressure chamber that collects fluid discharged from a hydraulic pump and an orifice that communicates with the high-pressure chamber and generates flow resistance, closes the orifice when the high-pressure chamber exceeds a predetermined pressure. And a relief means for causing the pressure oil in the high pressure chamber to fall due to an external signal.

[0006]

According to the hydraulic power transmission joint having such a structure, when the vehicle travels with torque transmission, it is possible to obtain the torque transmission and the lock characteristic according to the road surface condition, and the torque transmission is not required. , The free state can be set preferentially by the relief means at any time,
It exhibits excellent functions for so-called anti-lock braking control and prevention of tight corner braking phenomenon.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the hydraulic power transmission joint according to the present invention will be described below with reference to the drawings. First, the overall structure will be described based on the cross-sectional view of FIG. Reference numeral 2 is an input shaft to which a driving force is input, and 4 is a nonmagnetic housing supported by the input shaft 2 via a bearing 6 so as to be rotatable relative to the spline joint 8 formed at a side end of the housing 4. An output shaft (not shown) is connected.

An accumulator piston 10, which is slidable parallel to the shaft, is housed in a piston chamber formed on the spline joint 8 side of the housing 4, and a return is interposed by a retainer 12 fixed inside the housing 4. The oil seal 16 is urged to the left by the spring 14 and
And the O-ring 17 seals the piston chamber. 18
Is a cam provided inside the housing 4 via a thrust needle 20, and on the inner end surface on the left side of the cam 18, a cam surface 22 in which four cam peaks and one cam valley are alternately formed Have Further, the positioning protrusion 4a formed on the inner peripheral end of the housing 4 and the positioning groove 18a formed on the outer peripheral end of the cam 18 are loosely fitted to each other, so that the cam 18 circumferentially forms a predetermined angle θ with respect to the housing 4. It is possible to rotate only within the range.

Here, the angle θ at which the cam 18 can rotate in the circumferential direction with respect to the housing 4 is set to θ≈π / Nc, where Nc is the number of cam peaks of the cam 18. A rotor 24 is spline-fitted to the input shaft 2 and has a plurality of plunger chambers 26 formed in the circumferential direction.
The number of plunger chambers 26 is determined by a predetermined relationship based on the number of cam ridges provided on the cam surface 22 of the cam 18. In this embodiment, seven plunger chambers are provided for four cam ridges. 26 are formed at equal intervals.

A plunger 28 is slidably accommodated in each plunger chamber 26 via a return spring 30, and an intake / discharge hole 32 is formed in the bottom of each plunger chamber 26. 34 is a rotary valve,
It is fixed inside the housing 4 and is supported so as to be rotatable relative to the input shaft 2 via a ball bearing 36.

FIG. 2 (plan view of the rotary valve 34)
As shown in FIG. 4, four intake ports 38 and discharge ports 40 are alternately formed on the surface of the rotary valve 34 on the rotor 24 side at equal intervals, and the intake port 38 further includes an oil supply portion outside the rotor 24. An intake passage 42 communicating with 44 is formed. On the other hand, the discharge port 40 does not communicate with the oil supply unit 44, but communicates with a high pressure chamber 46 described later. Reference numeral 47 is a fitting groove for fitting and fixing inside the housing 4.

Further, as shown in FIG. 1, the rotary valve 34 has a first valve mechanism X having a first spool 48.
And a second valve mechanism Y having the second spool 50 is configured. In addition, in FIG. 2, the first valve mechanism X is
The second valve mechanism Y is provided corresponding to the specific suction port 38, and is provided corresponding to the specific discharge port 40. The sectional view of FIG. 1 shows a sectional structure of a portion corresponding to an imaginary line α-α shown in FIG. 2, and the upper side of the central axis Q in FIG. 1 shows a suction process and the lower side shows a discharge process state.

More specifically, referring to FIG. 1, the first spool 48 and the second spool 50 are slidably inserted in the axial direction, respectively, and the high pressure chamber 46 and the spool hole passing at one end thereof pass through. The connection between the suction passage 42 and the high-pressure chamber 46 is opened / closed according to the movement position of the first spool 48 formed. An orifice 54 is provided between one end of the spool hole into which the second spool 50 is inserted and the low pressure oil supply portion 44, and opens or closes the connection between the high pressure chamber 46 and the orifice 54 according to the moving position of the spool 50. ..

Further, the second spool 50 is elastically biased to the left side of the drawing by a spring 58 interposed in a support member 56 fixed to one discharge port 40, and as shown in an enlarged view in FIG. , Area A1 of the end surface on the discharge port 40 side
And the area A2 of the end surface on the high pressure chamber 46 side is designed to satisfy the relationship of A1> A2. Reference numeral 60 denotes a retainer fixed to the inside of the housing 4 by a retaining ring 62 and sealed between the input shafts 2.

Reference numeral 64 denotes a ring-shaped movable magnetic body having a fixed end of the first spool 48 and an end portion facing the second spool 50, and a spring 66 interposed at one end of the rotary valve 34 in FIG. Is elastically biased to the left side of. The movable magnetic body 64 is magnetized so as to be moved by a magnetic force generated by a solenoid 67 described later. 67
Is an electromagnetic solenoid provided on the outside of the retainer 60, and is composed of a magnetic frame 68 and a solenoid coil 70. It can be moved to the right by digging into the spring 66.

Next, the operation of this embodiment will be described with reference to FIGS. First, when the current is not supplied to the solenoid coil 70, as shown in FIG. 1, the movable magnetic body 64 is moved by the spring 66 in the direction away from the rotary valve 34, and at the same time, the first spool 48 is also moved in the same direction. As a result, the space between the high pressure chamber 46 and the suction passage 42 is closed. Further, the second spool 50 is moved to the left side in FIG. 1 by the spring 58, and the high pressure chamber 46 and the orifice 54 are moved.
Connect.

The positional relationship between the cam 18, the rotor 24, and the rotary valve 34 in this state is as shown in the sectional view of FIG. In FIG. 4, when a rotational speed difference occurs between the cam 18 and the rotor 24, a certain plunger 28 is in the suction process (indicated by an upper arrow).
Is a positional relationship in which the suction port 38 of the rotary valve 34 and the suction / discharge hole 32 of the plunger chamber 26 communicate with each other, and oil is sucked into the plunger chamber 26 from the suction passage 42 through the suction / discharge hole 32 of the rotor 24, and a certain plunger 28 discharges it. In the process (indicated by the lower arrow), the relationship is opposite to that in the suction process, and the suction / discharge hole 32 of the plunger chamber 26 formed in the rotor 24 is connected to the high pressure chamber 46 via the discharge port 40 of the rotary valve 34. Lead to Then, such a suction process and a discharge process of the plunger 28 occur alternately for the seven plungers 28 as shown in FIG. 4, and since the discharge side and the suction side communicate with each other through the orifice 54 of the rotary valve 34, the orifice A pressure corresponding to the flow resistance of 54 is generated on the discharge side, and torque is transmitted between the cam 18 and the rotor 24.

Further, as the difference in rotational speed between the cam 18 and the rotor 24 increases, the pressure on the discharge port 40 and the high pressure chamber 46 communicating with it increases accordingly. Here, the second spool 50 is designed such that the area A1 of the side surface on the side of the discharge port 40 and the area A2 of the side surface on the side of the high pressure chamber 46 are A1> A2, as shown in FIG. As the pressure in the discharge port 40 and the high pressure chamber 46 rises,
Gradually move into the spring 58 and move to the right side in FIG.
Then, as shown in FIG. 5, when the second spool 50 moves to a predetermined right end position, the high pressure chamber 46 and the orifice 54 are moved.
By closing the gap between them, a so-called locked state is achieved, and the cam 18 and the rotor 24 rotate substantially integrally regardless of a further increase in the rotational speed difference.

Therefore, the torque transmission characteristic when the current is not supplied to the solenoid coil 70 is as shown in characteristic curves A and B of FIG.
Within the range of the rotational speed difference N until the valve 6 and the orifice 54 are closed, a transmission torque (characteristic curve A) corresponding to the flow resistance of the orifice 54 is obtained. Locked regardless (characteristic curve B)
Becomes

Next, when a direct current having a predetermined polarity is supplied to the solenoid coil 70, a magnetic path passing through the magnetic frame 68 and the movable magnetic body 64 is generated as shown in FIG. The movable magnetic body 64 and the first spool 48 move to the suction port 38 side. As a result, the space between the high pressure chamber 46 and the low pressure suction port 38 is opened, and the high pressure chamber 46 is opened.
Pressure is lost.

Therefore, as shown in FIG. 6, when a current is supplied to the solenoid coil 70 by the second spool in the locked state, the locked state is released, and the torque transmission between the cam 18 and the rotor 24. It switches to a so-called free state that is not established. By the way, the first spool 48
Is for controlling the switching between the free state and the other torque transmission states (including the lock state).
7 has a function of switching to the free state with priority over the operation of the spool 50, and not only switches from the above-mentioned locked state to the free state, but also switches to the free state at the time of torque transmission shown by the characteristic curve A in FIG. Alternatively, the free state can be set before torque transmission occurs. Therefore, when the current is supplied to the solenoid coil 70 and the free state is set by the first spool 48, the characteristic becomes like the characteristic curve C in FIG. 7, and torque transmission cannot be obtained.

As described above, according to this embodiment, normal torque transmission can be obtained until the rotational speed difference between the input shaft and the output shaft reaches a certain value, and when it exceeds that value, the locked state is automatically established. Since the vehicle has a switching function, it is possible to prevent the wheels from idling and improve the running performance when the vehicle travels on a sandy or slippery road surface. In addition, since it is possible to make the transmission torque fall into a free state at any time by a magnetic means using a solenoid, if it is desired to control without transmitting power to the wheels, for example, lock the wheels during sudden braking. It is possible to freely control the setting of the free state in so-called anti-lock braking control to prevent it, and the setting of the free state in order to prevent the so-called tight corner braking phenomenon in tight corners by external signals. It is possible to provide an effective control function for ensuring safety.

[0023]

As described above, according to the present invention,
A hydraulic pump that is provided between the input and output shafts that can rotate relative to each other, is driven by the rotational speed difference between the two shafts, a high pressure chamber that collects the fluid discharged from the hydraulic pump, and a flow resistance that communicates with the high pressure chamber. In a hydraulic power transmission joint provided with an orifice for generating, a closing means for closing the orifice when the high pressure chamber exceeds a predetermined pressure, and an external signal,
Since the relief means for losing the pressure oil in the high-pressure chamber is provided, when the vehicle is traveling with torque transmission, it is possible to perform appropriate control according to the road surface condition, and the torque transmission of the vehicle is not required. When performing control, the relief means can preferentially set the free state at any time, providing an excellent hydraulic power transmission joint that can perform a wide range of control to ensure the safety of vehicle running. it can.

[Brief description of drawings]

FIG. 1 is a sectional view showing the overall structure of an embodiment of the present invention.

FIG. 2 is a plan view showing the structure of a rotary valve.

FIG. 3 is a sectional view showing the shape of a second spool.

FIG. 4 is an explanatory diagram illustrating a torque transmission operation.

FIG. 5 is a partial cross-sectional view for explaining the operation in the locked state.

FIG. 6 is a partial cross-sectional view for explaining the operation in the free state.

FIG. 7 is a characteristic diagram showing power transmission characteristics.

[Explanation of symbols]

 2; Input shaft 4; Housing 18; Cam 22; Cam surface 24; Rotor 26; Plunger chamber 28; Plunger 30; Return spring 32; Suction / discharge hole 34; Rotary valve 38; Suction port 40; Discharge port 42; Suction passage 44 Oil supply unit 46; high pressure chamber 47; fitting groove 48; first spool 50; second spool 54; orifice 56; support member 58; spring 60; retainer 62; retaining ring 64; movable magnetic body 66; spring 67; Solenoid 68; Magnetic Frame 70; Solenoid Coil

Claims (1)

[Claims] 1. A hydraulic pump provided between relatively rotatable input / output shafts and driven by a rotational speed difference between these shafts, a high pressure chamber for collecting discharge fluid from the hydraulic pump, and a high pressure chamber in the high pressure chamber. In a hydraulic power transmission joint having an orifice communicating with each other to generate flow resistance, a closing means for closing the high pressure chamber when the high pressure chamber exceeds a predetermined pressure, and a pressure oil in the high pressure chamber is lost by an external signal. A hydraulic power transmission joint characterized by comprising relief means for making it fall.