JPH0442582Y2 - - Google Patents

Description

[Detailed description of the invention] [Field of industrial application] The present invention relates to a control device for a pressure transducer, and in particular,
The present invention relates to a pressure transducer control device that allows fine adjustment of the output of the pressure transducer.

[Conventional technology]

In conventional part-time four-wheel drive vehicles,
A hydraulic clutch is used as a means for switching between 2WD and 4WD driving modes, and an on/off switching valve is used to turn on and off oil supply to the hydraulic clutch. An example of such a conventional example is, for example, Japanese Patent Application Laid-open No. 58-
Publication No. 56926 describes an input shaft from an engine, a front wheel output shaft arranged parallel to the input shaft and always connected to the input shaft, and a front wheel output shaft disposed coaxially behind the input shaft. A rear wheel output shaft is detachably connected to the front wheel output shaft via a hydraulic clutch, which will be described later, and an oil pump installed in the engine or transmission, and the front wheel output is supplied with oil from the oil pump. A hydraulic clutch which disconnects both outputs by locking the shaft and the rear wheel output shaft to set the vehicle to 4WD or cutting off the oil supply, and a hydraulic clutch which is interposed between the oil pump and the hydraulic clutch. A four-wheel drive vehicle is disclosed that has a control device (switching valve) that controls the flow rate of oil supplied to the vehicle. This control device consists of an inlet port that communicates with the oil passage on the oil pump side, an outlet port that communicates with the oil passage on the hydraulic clutch side, a drain port that releases oil, a valve body that opens and closes each of these ports, and a valve body. It has a solenoid that reciprocates, a switch that turns the solenoid on and off, and a power source.

In the above configuration, when the switch is turned on and the solenoid is energized, the valve body moves and closes the drain port while opening the inlet and outlet ports, so the hydraulic pressure generated in the oil pump is transferred to the hydraulic clutch. The front and rear wheel output shafts are locked and 4WD is achieved. Then, when the switch is turned off, the valve body is moved in the opposite direction by the return spring to open the drain port while blocking the inlet port, so that the oil in the hydraulic clutch flows through the outlet port and drain port. After that, the oil is drained and the rear output shaft becomes free, realizing 2WD.

Further, even when the differential of a final reduction gear such as a differential device described in Japanese Patent Publication No. 57-4536 is limited by hydraulic pressure, the above-mentioned on/off control device has been used as the hydraulic pressure adjusting means.

[Problem that the invention attempts to solve]

However, in the case of a control device for oil flow to a hydraulic clutch used in conventional four-wheel drive vehicles,
Depending on whether the solenoid is turned on or off, the hydraulic pressure supplied to the hydraulic clutch is either the maximum or zero, and it has been impossible to regulate the pressure to an intermediate pressure. Therefore, even if it is desired to transmit a desired torque from the front wheels to the rear wheels depending on driving conditions, for example, there is a problem in that it is not possible to achieve this.

Furthermore, if the above-mentioned on/off control device is used as a hydraulic pressure adjustment means when the differential of a final reduction gear such as a differential gear is limited by hydraulic pressure, it becomes impossible to finely adjust the degree of differential limitation. However, it is not practical because the degree of differential restriction cannot be finely adjusted according to the driving conditions.

[Means and actions for solving problems]

This invention was made in view of the above,
In order to enable fine adjustment of the hydraulic pressure supplied to pressurized objects such as hydraulic clutches or final reduction gears, we use a pressure converter that converts air pressure into hydraulic pressure and outputs it to the pressurized object, and a proportional solenoid. A spool valve includes a valve body configured to finely adjust the amount of displacement by balancing a pressing force in one direction and a pressing force in the other direction by hydraulic pressure output from a pressure converter; an outlet path that connects the transducer and the spool valve; an atmospheric pressure path that communicates with the outlet path to bring the pressure transducer into a maximum pressurized state when the valve body is displaced in one direction; a first negative pressure path that communicates with the outlet path to depressurize the pressure transducer when the body is displaced in the other direction; a bypass for transferring hydraulic pressure, a second load path that constantly applies an absorption force in the direction of putting the pressure transducer in a pressurized state, and a second load path that always applies a pressing force in the direction of putting the pressure transducer in a non-pressurized state. The present invention provides a control device for a pressure transducer having an additional return spring.

〔Example〕

Hereinafter, the pressure transducer control device according to the present invention will be described in detail with reference to the drawings.

The drawings show an embodiment of the present invention, in which reference numeral 1 is a control device, 2 is a pressure transducer (atmospheric pressure/hydraulic transducer) whose pressurizing force is controlled by the control device 1, and 3 is a pressure transducer from the pressure transducer 2. Each figure shows a final reduction gear (a pressurized object) such as a differential device whose differential is controlled (limited) by hydraulic pressure.

The control device 1 consists of a spool valve 5 and a proportional solenoid 6. The spool valve 5 consists of a valve case 7 and a valve body 8 that can reciprocate in the axial direction in a chamber 7a inside the valve case 7.The outer peripheral wall of the case 7 has a negative pressure inlet 9 and an atmospheric pressure inlet. 10
and an outlet 11 are respectively formed. On the other hand, a bypass port 12 is formed in one end surface in the axial direction. Negative pressure inlet 9 is connected to first negative pressure path 14
The negative pressure tank 13 and the atmospheric pressure inlet 10 are connected to the outside air through an atmospheric pressure path 15, respectively. The outlet 11 is connected to the pressure transducer 2 via an outlet path 16 . The valve body 8 has a communication groove 8a extending over the entire circumference on its outer peripheral surface, and while this communication groove 8a constantly communicates with the outlet 11, it communicates only with the negative pressure inlet 9 in the process of axial movement. It can communicate only with the atmospheric pressure inlet 10, or it can be closed by the intermediate wall 17.

The proportional solenoid 6 is connected to the chamber 7 of the spool valve 5.
A cylinder 2 having a chamber 21a in communication with a
1, a coil 22 which is disposed on the inner wall of the chamber 21a and whose magnetic force can be controlled by a current from a control unit 20 for adjusting the final reducer (object to be pressurized) 3; It has a piston 23 which is disposed within 21a so as to be freely movable in the axial direction and which is integrated with the valve body 8. Piston 23
is configured to be movable in the direction of the spool valve 5 (rightward in the drawing, hereinafter referred to as the protrusion direction) by a distance corresponding to the magnetic force of the coil 22.

The pressure transducer 2 is always urged in the non-pressurizing direction (leftward in the drawing) by a return spring 25, and receives atmospheric pressure from the atmospheric pressure path 15 and outlet path 16, and from the second negative pressure pulse 26. A diaphragm 28 that is sucked in the pressurizing direction (rightward in the drawing) by the negative pressure of
The final reduction gear 3 and the cylinder 30 are connected by an oil passage 31. The bypass port 12 on one end surface of the spool valve 5 is connected to the oil passage 31 via a bypass 32, and the hydraulic pressure in the oil passage 31 is applied to the one end surface of the valve body 8 by this bypass. ing. Therefore, the valve body 8 and the piston 23 simultaneously receive a pressing force in the projecting direction (rightward in the drawing) by the proportional solenoid and a pressing force in the returning direction (leftward in the drawing) by the hydraulic pressure, and the balance between the two pressing forces is maintained. The axial position is determined by Since the valve body 8 is thus subjected to pressing forces in opposite directions from both ends in the axial direction, it is possible to finely adjust the amount of movement in the axial direction by controlling the current from the control unit 20.

The drawing shows a state where the communication groove 8a is closed by the intermediate wall 17, and in this state, both paths 14 and 15 are closed.
is blocked, the diaphragm 28 has a second
Only the negative pressure from the negative pressure pulse 26 acts. Therefore, the piston 29 is moved by the return spring 25.
The pressing force in the non-pressurizing direction and the second negative pressure pulse 26
It is held at the intermediate position by the balance with the suction force in the pressurizing direction from

The final reduction gear 3 receives hydraulic pressure from the pressure converter 2 and has its differential movement limited. Clutch means such as a hydraulic clutch or a multi-plate clutch that is pressurized by hydraulic pressure to create friction is used as a means for limiting differential movement.

In addition, the pressurized object is configured such that the control device 1 and the pressure transducer 2 can mutually switch between two-wheel drive mode and four-wheel drive mode, and realize an intermediate mode between them.
It may also be connected to a hydraulic clutch or the like for connecting and disconnecting the front wheel drive shaft and the rear wheel drive shaft.

In the above configuration, the control unit 2
When the coil 22 is strongly excited by 0, the piston 23 and the valve body 8 move in the protruding direction (rightward in the drawing), the atmospheric pressure path 10 and the communication groove 8a communicate with each other, and the communication groove 8a communicates with the atmospheric pressure path 10 through the outlet path 16. Pressure is applied to the diaphragm 28 of the pressure transducer 2 in the pressurizing direction (rightward). Then, the balance between the negative pressure from the second negative pressure path 26 and the return force of the spring 25 is lost, and the pressure plate 28 moves in the pressurizing direction, supplying strong hydraulic pressure to the final reduction gear 3 (hydraulic clutch). to limit (stop) the differential with strong force.

Next, when the excitation of the coil 22 becomes zero, the piston 23 and the valve body 8 move in the return direction (to the left) to open the negative pressure path 14.
and the negative pressure path 9 are communicated with each other, and the pressure plate 28 is returned to the non-pressure direction. At this time, the oil in the final reduction gear 3 (hydraulic clutch) is drained and differential operation becomes possible.

In the intermediate pressure state shown by the solid line, the oil pressure takes an intermediate value due to the balance between the negative pressure from the second negative pressure path 26 and the spring 25 as described above. However, the valve body 8 can be displaced little by little in the left-right direction other than the illustrated intermediate position, and can output various intermediate oil pressure values depending on the displaced position.

[Effect of idea]

As explained above, according to the pressure transducer of the present invention, the pressure transducer converts air pressure into hydraulic pressure and outputs it to the pressurized object, the pressure force in one direction by the proportional solenoid, and the pressure transducer output from the pressure transducer. a spool valve including a valve body configured to finely adjust the amount of displacement by balancing with a pressing force in the other direction by hydraulic pressure; an outlet path connecting the pressure transducer and the spool valve; an atmospheric pressure path that communicates with the outlet path when the valve body is displaced in one direction to bring the pressure transducer into a maximum pressurized state; and an atmospheric pressure path that communicates with the outlet path when the valve body is displaced in the other direction. a first negative pressure path communicating with one end of the valve body to transfer hydraulic pressure from the pressure transducer, and pressurizing the pressure transducer. Since it has a second load path that constantly applies an absorbing force in the direction of bringing the pressure transducer into the non-pressurized state, and a return spring that constantly applies a pressing force in the direction of bringing the pressure transducer into the non-pressurized state, the hydraulic clutch or terminal It is possible to finely adjust the hydraulic pressure supplied to a pressurized object such as a reduction gear.

[Brief explanation of drawings]

The drawing is a schematic diagram showing the configuration of an embodiment of the invention. Explanation of symbols, 1... Control device, 2... Pressure transducer, 3... Final reducer (pressurized object), 5... Spool valve, 6... Proportional solenoid, 7... Valve case, 7a... ...Chamber, 8...Valve body, 9...Negative pressure inlet, 10...Atmospheric pressure inlet, 11...Outlet,
12... Bypass port, 14... First negative pressure path,
15... Atmospheric pressure path, 16... Exit path, 17...
...Intermediate wall, 20...Control unit, 21
...Cylinder, 21a...Chamber, 22...Coil,
23... Piston, 25... Return spring, 26... Second negative pressure path, 28... Pressure plate,
29... Piston, 30... Cylinder, 31...
Oil line, 32...bypass.

Claims (1)

[Scope of utility model registration request] The pressure transducer converts air pressure into hydraulic pressure and outputs it to the pressurized object, and the balance between the pushing force in one direction by the proportional solenoid and the pushing force in the other direction by the hydraulic pressure output from the pressure converter a spool valve having a valve body configured to be able to finely adjust the amount of displacement; an outlet path connecting the pressure transducer and the spool valve; and an outlet path when the valve body is displaced in one direction. an atmospheric pressure path that communicates with the outlet path to place the pressure transducer in a pressurized state; and a first atmospheric pressure path that communicates with the outlet path to place the pressure transducer in a non-pressurized state when the valve body is displaced in the other direction. a negative pressure path, a bypass communicating with one end of the valve body and transferring hydraulic pressure from the pressure transducer, and a second negative pressure path that constantly applies absorption force in the direction of pressurizing the pressure transducer. A control device for a pressure transducer, comprising a pressure path and a return spring that constantly applies a pressing force in a direction to bring the pressure transducer into a non-pressurized state.