JPH0611069A - Air bleeder construction of electromagnetic pressure control valve - Google Patents

Abstract

PURPOSE:To provide an air bleeder construction of an electromagnetic pressure control valve by which remaining air in a solenoid valve main body can be simply drawn out. CONSTITUTION:This electromagnetic pressure control valve is provided with a valve main body 11 having a slidable spool 17, and a solenoid valve main body having a slidable valve body 31 for controlling pilot pressure applied on the spool. The operating line of the valve main body 31 is arranged so as to incline against the operating line of the spool 17, and the solenoid valve main body is arranged in a position lower than that of the valve main body 11.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an air bleeding structure for an electromagnetic pressure control valve for automatically bleeding air remaining inside a sonoid valve body.

[0002]

2. Description of the Related Art Generally, a hydraulic electromagnetic pressure control valve having a valve body having a slidable spool and a solenoid valve body having a slidable valve body for controlling pilot pressure applied to the spool is It is known (for example, Jitsukaihei 3-72173).

[0003]

In this type, the air contained in the hydraulic oil tends to remain inside the solenoid valve body, and if this remains, a so-called oscillation phenomenon occurs and the oil pressure control by the control valve is performed. Is unstable.

In order to solve this problem, if an air vent hole is provided, the structure of the solenoid valve body becomes complicated, leading to an increase in cost. If no air vent measures are taken, it will be disassembled when air vent occurs, There are problems that maintenance such as assembling is required, and that running-in operation is required at the time of starting.

Therefore, an object of the present invention is to solve the problems of the above-mentioned conventional techniques and provide an air bleeding structure for an electromagnetic pressure control valve capable of easily bleeding air remaining in the solenoid valve body. Especially.

[0006]

To achieve the above object, the present invention provides a valve body having a slidable spool,
In a solenoid pressure control valve having a solenoid valve body having a slidable valve body for controlling pilot pressure applied to a spool, a solenoid is arranged with the operating line of the valve body inclined with respect to the operating line of the spool. It is characterized in that the valve body is arranged at a lower position than the valve body.

[0007]

[Operation] During operation of the electromagnetic pressure control valve, the hydraulic oil is
Naturally, the inside of the solenoid valve body having the valve body is also filled. Air may be mixed in the hydraulic oil filled here. Therefore, according to the present invention, when the pressure control valve is installed, by arranging the solenoid valve main body at a lower position than the valve body, the air mixed in the hydraulic fluid goes to the upper level. It is automatically discharged to the outside from the valve body side. That is, according to this, the air can be evacuated extremely easily and automatically by utilizing the property that the air moves upward in the working oil without performing the maintenance or the like as in the conventional case.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

In FIG. 1, reference numeral 11 is a valve body.
Inside the valve body 11, there is formed a spool hole 12 penetrating from the right end to the left end in FIG. 1 (hereinafter, left and right shall refer to left and right in FIG. 1), and a drain opening to the spool hole 12 is formed. Port 13, pump port 14, actuator port 15 and tank port 1
6 are sequentially formed from the right side to the left side.

Drain port 13 and tank port 16
Is connected to a tank (not shown). The pump port 14 is connected to a fluid pressure supply source (not shown) such as a hydraulic pump, and the actuator port 15 is connected to an actuator such as a clutch pack of a clutch.

A spool 17 is slidably provided in the spool hole 12, and a valve seat 18 is fixed to the right end of the spool hole 12.

On the outer circumference of the spool 17, the pump port 1
4 is formed between the actuator port 15 and the actuator port 15, and a second partition portion 17b is formed between the actuator port 15 and the tank port 16. Also, the spool 17 is
The return spring 19 biases the valve seat 18 toward the valve seat 18. When the spool 17 hits the valve seat 18, the first partition portion 17a disconnects the pump port 14 and the actuator port 15 from each other. When the actuator port 15 and the tank port 16 communicate with each other and the spool 17 moves against the biasing force of the return spring 19, the pump port 14
And the actuator port 15 communicate with each other, and the actuator port 15 is connected by the second partition 17b.
The tank port 16 is cut off.

Here, the outer diameter of the first partition 17a is larger than the outer diameter of the second partition 17b.
Therefore, the pump port 14 and the actuator port 15
When the actuator port 15 and the tank port 16 are disconnected from each other while the hydraulic fluid flows from the pump port 14 into the actuator port 15 and the pressure of the actuator port 15 rises, the first partition portion 17
The spool 17 is pressed to the right due to the difference in pressure receiving area based on the difference in outer diameter between the a and the second partition portion 17b.

The return spring 19 is for preventing the spool 17 from rattling in the axial direction, and its urging force is set to be extremely small.

A recess 20 extending in the axial direction of the spool 17 is formed at the center of the right end surface of the spool 17 facing the valve seat 18. The interior of the recess 20 is a pilot chamber 21. The pilot chamber 21 communicates with the pump port 14 through a throttle hole 22 and a mounting hole 23 formed in the spool 17, and a valve hole 24 and a valve housing hole 2 formed in the valve seat 18, respectively.
5 and the lateral hole 26 to communicate with the drain port 13.

At the center of the left end face of the valve seat 18 facing the spool 17, a protrusion 27 is formed which is fitted in the recess 20 so as to be relatively slidable. In this case, the projecting portion 27 is fitted in the recess 20 in a liquid-tight manner, but it is not necessary to be strictly liquid-tight. In addition, on the tip surface of the protrusion 27,
The valve hole 24 is open.

Further, the valve seat 18 and the spool 17
Between the opposing surfaces of the damper chamber 28 and the outer peripheral surface of the protruding portion 27 and the inner peripheral surface of the spool hole 12.
Are sectioned. The damper chamber 28 is always in communication with the pilot chamber 21 via the valve hole 24 by the communication passage 29 having the orifice 29a. An annular step portion 30 is formed at the peripheral edge of the left end surface of the valve seat 18 so that the volume of the damper chamber 28 does not become zero even when the spool 17 hits the valve seat 18 (the state of FIG. 1). When the spool 17 hits the valve seat 18, the step portion 30 and the spool 1
A damper chamber 28 is defined by the right end surface of 7 and the inner peripheral surface of the spool hole 17.

On the other hand, at the left end of the spool hole 12,
An oil chamber 37 is defined by the spool 17 and the spring retainer 36. The oil chamber 37 communicates with the tank port 16 through a throttle hole 38 and a communication hole 39 formed in the spool 17, respectively. The throttle hole 38 always communicates with the tank port 16, but the communication hole 39 blocks the second partition portion 17b between the actuator port 15 and the tank port 16 when the spool 17 moves to the left. After that, when further moved by a predetermined minute distance, it is arranged so as to be blocked by the inner peripheral surface of the spool hole 12. Therefore, when the spool 17 further moves to the left after the communication hole 39 is shielded, the working oil in the oil chamber 37 flows out through the throttle hole 38, and the resistance at that time causes the spool 17 to move. The speed of movement to the left can be kept low.

A feature of this embodiment is that the valve housing hole 25 is formed obliquely in the valve seat 18, and the valve body 31 is slidably housed in the valve housing hole 25. Has been done. That is, the valve body 31 is arranged so that its operating line is oblique to the operating line of the spool 17.

The valve body 31 is capable of closing the valve hole 24, and is biased by a spring 32 in a direction away from the valve hole 24. On the other hand, the magnetic force of the solenoid 33 causes the movable iron core 34 and the spring 35 to move. It is adapted to be pressed in a direction approaching the valve hole 24 via the. Further, the spring 35 is housed in the spring housing hole 41, and the spring housing hole 41
Communicates with the movable iron core accommodation hole 42 that accommodates the movable iron core 34, and also communicates with the drain port 13 through the communication hole 43.

The movable iron core 34 including the valve body 31, the solenoid 33, etc., form a solenoid valve body.

Thus, according to this embodiment, the valve body 11
Solenoid 3 with respect to the operating line of the spool 17 in
3 is characterized in that the operating line of the valve body 31 pushed by the magnetic force of 3 is arranged so as to be inclined, and when the pressure control valve is attached to the fixed portion 90 of an industrial machine or the like, the valve body is It is characterized in that it is attached so that the solenoid 33 side is located lower than 31.

In the solenoid proportional control valve having the above structure, when the solenoid 33 is energized, the movable iron core 34 presses the valve body 31 via the spring 35 and approaches the valve hole 24 against the biasing force of the spring 19. Then, the valve body 31 is moved. Then, the pilot pressure in the pilot chamber 21 rises, and along with this, the pressure in the damper chamber 28 (hereinafter referred to as damper pressure).
Rises. Then, the pilot pressure and the damper pressure cause the spool 17 to move against the urging force of the spring 19 so that the pump port 14 and the actuator port 15 communicate with each other, and the actuator port 15 and the tank port 16 also communicate with each other. To cut off.

Then, hydraulic oil flows from the pump port 14 into the actuator port 15, and the pressure of the actuator port 15 rises accordingly. When the pressure at the actuator port 15 increases, the spool 1
7 is pushed back. However, actuator port 15
17 due to the pressure of the spring and the biasing force of the return spring 19
When the pressing force on the spool becomes equal to the pressing force on the spool 17 due to the pilot pressure and the damper pressure, the spool 17 stops.

When the spool 17 is stopped,
The right end edge of the first partition portion 17a substantially closes the space between the pump port 14 and the actuator port 15, and the left end edge of the second partition portion 17b is the actuator port 15.
Since the space between the tank port 16 and the tank port 16 is almost closed, a so-called stable state is achieved.

By the way, during such an operation, the hydraulic oil naturally fills the spring accommodating hole 41 and the movable iron core accommodating hole 42 on the valve body 31 side. Then, when air is mixed into the hydraulic oil filled therein, an oscillation phenomenon occurs in the valve body 31 pushed by the magnetic force of the solenoid 33, and when this phenomenon occurs, the control pressure of the control valve becomes unstable. In such cases,
Conventionally, maintenance or the like for removing air is required.

According to this embodiment, however, when the pressure control valve is installed, the solenoid 33 side is lower than the valve body 31, so that the movable iron core receiving hole 4
2. Since the air in the spring accommodating hole 41 is directed upward, this air is communicated with the drain port 13 through the communication hole 43 and is discharged to the outside. That is, according to this
By utilizing the property that air moves upward in the hydraulic oil without performing maintenance or the like as in the past, the air can be evacuated extremely easily and automatically.

Further, since the air is automatically evacuated due to the structure, the running-in operation for bleeding the air at the time of start-up is unnecessary, and stable pressure control is performed even at high temperature.

As is apparent from the above, the present invention utilizes the property that air moves upward in the hydraulic oil, so that if the solenoid 33 side is arranged at a low position, as shown in FIGS. 2 and 3. Obviously, any configuration may be used.

That is, FIGS. 2 and 3 show a so-called cartridge type pressure control valve in which a valve body 100 is provided in a block 101 and a sonoid valve 102 is provided in a block 1.
It is constructed by bolting to 0. FIG. 2 shows the mounting surface on the block 101 side tilted by an angle θ,
FIG. 3 shows the solenoid valve 102 side mounting surface inclined by an angle θ. The angle is preferably about 5 ° <θ <20 °.

[0031]

As is apparent from the above description, according to the present invention, since the solenoid valve main body is arranged at the low position,
The air that remains there moves upward in the hydraulic oil, so
The residual air is automatically discharged to the outside from the valve body side through, for example, a drain port.

[Brief description of drawings]

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

FIG. 2 is a partially cutaway sectional view showing another embodiment.

FIG. 3 is a partially cutaway sectional view showing another embodiment.

[Explanation of symbols]

 11 Valve Body 12 Spool Hole 14 Pump Port 15 Actuator Port 17 Spool 18 Valve Seat 20 Recess 21 Pilot Chamber 24 Valve Hole 27 Projection 28 Damper Chamber 29a Orifice 31 Valve Disc 33 Solenoid

Claims (1)

[Claims] 1. A valve body having a slidable spool,
An electromagnetic pressure control valve comprising a solenoid valve main body having a slidable valve body for controlling pilot pressure applied to the spool, wherein the operating line of the valve body is inclined with respect to the operating line of the spool. An air bleeding structure for an electromagnetic pressure control valve, wherein the solenoid valve body is arranged at a lower position than the valve body.