JP3522618B2 - Flow control device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flow rate control device for controlling the opening of a variable throttle by the thrust of a solenoid and ensuring a flow rate according to the opening.

[0002]

2. Description of the Related Art As a flow control device of this type, Japanese Patent Application No.
The one described in Japanese Patent Publication No. 1-59451 is conventionally known. In this conventional example, as shown in FIG. 2, a valve body 1 has a pump port 2 communicating with a pump P and a tank port 3 communicating with a tank T.
Further, the connecting member 4 is fitted into one end of the valve body 1, and the actuator port 6 is attached to the connecting member 4.
The port member 5 formed with is fixed. A power steering device PS is connected to the actuator port 6. Further, a spool hole 7 is formed in the valve body 1, and a spool 8 is slidably incorporated in the spool hole 7, and both sides thereof are divided into a control chamber 9 and a pilot chamber 10. Moreover, the pilot chamber 10 is provided with the spring 11.

The spool 8 constructed as described above is provided in the control room 9
And the pressure action of the pilot chamber 10 and the spring force of the spring 11 are balanced.
The opening of the tank port 3 is determined according to this balance position. Since the opening of the tank port 3 is determined in this manner, the flow dividing ratio of the flow rate of the pump P supplied to the side of the tank T and the flow rate supplied to the side of the power steering device PS is determined. . In other words, the flow rate supplied to the power steering device PS is controlled by controlling the split ratio.

It is the pump port 2 that determines the diversion ratio.
Is the opening degree of the variable throttle V provided in the flow process between the actuator port 6 and the actuator port 6. The variable diaphragm V mainly includes a diaphragm opening member 12 fixed to an opening portion of the connection member 4 and a diaphragm member 14 provided in a spool hole 13 of the connection member 4. The diaphragm opening member 4 and the diaphragm member 14 are arranged side by side in the axial direction. The throttle opening member 12 has a seat portion 15 formed at the right end of the drawing, and a valve portion 16 provided at the tip of the throttle member 14 in the seat portion 15.
Are facing each other. Then, the seat portion 15 and the valve portion 1
6 and 6 form a variable diaphragm V.

The pressure on the upstream side of the variable throttle V as described above acts on the pressure receiving surface of the spool 8 in the control chamber 9. Further, the pressure on the downstream side of the variable throttle V is introduced into the pilot chamber 10 via the pilot passage 18 formed in the valve body 1 and is applied to the pressure receiving surface of the spool 8 in the pilot chamber 10. Therefore, the spool 8 is stopped at a position where the pressure action on the upstream side of the variable throttle V, the pressure action on the downstream side of the variable throttle V, and the spring force of the spring 11 are balanced.

The spool 8 moves to the left in the drawing as the pressure difference across the variable throttle V increases, and the opening of the tank port 3 increases. Because the variable aperture V
When the pressure difference between the front and the rear becomes larger, the pressure in the control chamber 9 becomes higher than the pressure in the pilot chamber 10. Therefore, the force that pushes the spool 8 to the left in the drawing from the control chamber 9 side is from the pilot chamber 10 side. This is because the force that pushes the spool 8 to the right in the drawing becomes relatively larger. When the opening degree of the tank port 3 increases, the flow rate discharged to the tank T increases, so that the flow rate supplied to the power steering device PS side decreases.

The pressure difference generated before and after the variable throttle V is inversely proportional to the opening of the variable throttle V. That is, if the pressure in the control chamber 9 is constant, the variable throttle V
The pressure difference becomes smaller as the opening becomes larger, and the pressure difference becomes larger as the opening becomes smaller. And
In this conventional example, the opening of the variable diaphragm V is adjusted by controlling the axial position of the diaphragm member 14. The mechanism for adjusting the opening of the variable aperture V will be described below.

The throttle member 14 provided with the valve portion 16 constituting the variable throttle V is controlled in its movement by the proportional solenoid S. The proportional solenoid S includes a movable iron core 20, a fixed iron core 21, and a coil 23,
The diaphragm member 14 is fixed to the movable iron core 20 so that the movable iron core 20 and the diaphragm member 14 move integrally. Then, when a current is passed through the coil 23 to excite the fixed iron core 21, the movable iron core 20 is attracted, and the diaphragm member 14 moves in a direction of increasing the opening of the variable diaphragm V.

However, the movable iron core 20 and the fixed iron core 21 are
A spring 22 is provided between and, and the spring force causes the diaphragm member 14 to exert a force in the direction of closing the variable diaphragm V. Therefore, when the thrust force of the proportional solenoid S overcomes the spring force of the spring 22, the throttle member 1
4 moves to increase the opening of the variable aperture V. In addition,
The spring force of the spring 22 can be adjusted by an adjuster 29.

A load pressure is introduced into the back pressure chamber 27 provided with the spring 22 through the movable iron core 20 and the internal passage 26 formed in the throttle member 14. The reason why the load pressure is introduced into the back pressure chamber 27 in this way is as follows. That is, when a large load pressure acts only on the pressure receiving surface 28 of the throttle member 14, there is a risk that the throttle member 14 will move and the variable throttle V will open. However, if the load pressure is also introduced to the back pressure chamber 27 as described above and the acting force by the load pressure is applied to the movable iron core 20 from the opposite side,
Since the force due to the load pressure can be canceled, the above inconvenience does not occur. For this reason, the load pressure is introduced into the back pressure chamber 27.

The controller C controls the electric current supplied to the coil 23 of the proportional solenoid S based on the steering torque signal and the vehicle speed signal. For example, when the power steering device PS is in the neutral state and the steering torque signal is zero, the controller C sets the supply current to 0. When the supply current is 0, the attraction force by the proportional solenoid S is not generated, so the variable diaphragm V is kept closed. However, even when the variable throttle V is completely closed, a small amount of pressure oil is supplied to the power steering device PS side via the fixed throttle 24 formed in the aperture opening member 12. The reason for doing this is as follows.

That is, even when the power steering device PS is in a neutral state, a small amount of pressure oil is constantly supplied to the power steering device PS having an open center type switching valve to keep it in a standby state. Is. The power steering device PS is kept in a standby state in order to prevent a response delay during operation. Further, when current is no longer supplied to the proportional solenoid S due to a failure or the like, the power steering device PS is driven by the above-mentioned standby flow rate so as to perform a fail-safe function.

On the other hand, when the steering wheel is steered from the above state, the controller C controls the current based on the steering torque signal and the vehicle speed signal at this time. When the proportional solenoid S is excited by the current controlled in this way, the attraction force moves the diaphragm member 14 to open the variable diaphragm V. When the variable throttle V is opened, the spool 8 moves according to the pressure difference generated before and after the variable throttle V, and the flow rate supplied to the power steering device PS is determined.

As described above, in this conventional example, the opening of the variable diaphragm V is adjusted by the exciting current of the proportional solenoid S, and the power steering device P is adjusted by the opening of the variable diaphragm V.
The flow rate supplied to S is determined. Therefore, it is necessary to accurately control the opening of the variable aperture V, and the movement of the aperture member 14 that determines the opening of the variable aperture V must be smooth. For this reason, the processing accuracy of the sliding hole 13 incorporating the throttle member 14 is kept high.

[0015]

However, in this conventional example, the sliding hole 13 is directly formed in the connecting member 4. The connection member 4 requires a certain strength and a certain size in order to fix the three members of the valve body 1, the port member 5 and the proportional solenoid S. Therefore, the connecting member 4 is large and heavy. When it is attempted to form the sliding hole 13 in such a connecting member 4, since the connecting member 4 is heavy and large,
Since the handling is very difficult and the processing work is extremely difficult to perform, there is a problem that the processing cost is increased accordingly.

Further, in the above conventional example, the proportional solenoid S
When the valve is de-energized, the variable throttle V is completely closed.
The fixed aperture 24 must be purposely formed in order to supply the. However, since the fixed diaphragm 24 is separately formed in this way, there is a problem that the processing cost becomes high. Further, when adjusting the standby flow rate, the opening of the fixed throttle 24 to be machined must be changed for each device, which causes a problem in that the machining cost is high and it is not suitable for mass production. Further, since the diaphragm opening member 4, the diaphragm member 14 and the movable iron core 20 are arranged side by side in the axial direction, there is a problem that the entire apparatus becomes large in the axial direction. An object of the present invention is to provide a flow rate control device that can solve the above various problems.

[0017]

SUMMARY OF THE INVENTION The present invention is directed to a housing having a pump port and an actuator port formed therein, a spool hole formed in the housing, a spool slidably incorporated in the spool hole, and one of the spools. Of the control chamber, which is partitioned into the end face side of the spool and is always in communication with the pump port, the pilot chamber partitioned into the other end face side of the spool, and when the spool moves due to the pressure action of the control chamber and the pilot chamber, A tank port that communicates with the control chamber and whose communication opening degree with the control chamber is controlled according to the amount of movement of the spool, a throttle opening member having a flow path that communicates between the pump port and the actuator port, and this throttle. A variable diaphragm provided in the flow path of the opening member and a solenoid for adjusting the opening of the variable diaphragm are provided.

The diaphragm member, which is a constituent element of the variable diaphragm, has a valve portion at the tip thereof, and the valve portion and the seat portion provided in the diaphragm opening member together constitute the variable diaphragm, while the diaphragm member. The movable iron core of the solenoid is provided on the rear end side, and the spring force of the spring is applied from this movable iron core side to apply a force in the direction of reducing the opening of the variable throttle to the throttle member. Assuming a control device.

The first invention is based on the above-mentioned device,
A bearing is incorporated in the aperture opening member, the bearing is slidably supported by the bearing, and the variable aperture maintains a predetermined opening when the movable iron core comes into contact with one end of the bearing. It is characterized in that it is configured. A second invention is characterized in that, in the first invention, a groove is formed on the outer periphery of the bearing member, and the load pressure is guided to the movable iron core side through the groove. According to a third aspect of the present invention, in the first or second aspect of the invention, when the differential pressure before and after the variable throttle acts on the throttle member, the valve section and the seat section face each other so that the opening of the variable throttle increases. Is characterized by. A fourth invention is the diaphragm opening member according to the first to third inventions, wherein the movable iron core of the solenoid and the diaphragm member are incorporated in the diaphragm opening member, and the seat portion and the valve portion of the diaphragm member provided therein. It is characterized in that the variable aperture is constructed in combination.

[0020]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the embodiment shown in FIG. 1, the structure of a diaphragm opening member 30, a diaphragm member 31, and a movable iron core 32 of a proportional solenoid S is different from that of the conventional example, but a spool 8 is used.
Since the configuration for dividing the flow rate from the pump P into the tank T side and the power steering device PS side by the same as in the conventional example, the same components are denoted by the same reference numerals as in the conventional example, and a detailed description thereof will be given. Omit it.

As shown in FIG. 1, the aperture opening member 30 is fixed to the opening 40 of the housing h, and the aperture opening member 3
The proportional solenoid S is fixed on the right side of the drawing in FIG. Further, an assembly hole 33 is formed in the diaphragm opening member 30. A bearing 34 is fixed to the mounting hole 33 by press fitting or screwing, and a throttle member 31 is slidably incorporated in a sliding hole 35 of the bearing 34. That is, in this embodiment, the diaphragm member 31 is slidably supported by the bearing 34 provided inside the diaphragm opening member 30.

A valve portion 36 is formed at the tip portion on the left side of the drawing of the throttle member 31. And this valve portion 36
The variable aperture V is configured by making the sheet face the sheet portion 37 formed inside the aperture opening member 30. Further, a movable iron core 32 forming a proportional solenoid S is fixed to the rear end side of the diaphragm member 31. And this movable iron core 3
Most of the portion 2 is inserted into the enlarged diameter portion 38 formed in the aperture opening member 30. However, the expanded diameter portion 39 is also formed in the fixed iron core 21 so that when the movable iron core 32 moves in the right direction in the drawing, a part thereof is inserted. A sufficient gap s is formed between the movable iron core 32 and the expanded diameter portions 38, 39 so that the movable iron core 32 moves smoothly in the axial direction.

Further, grooves 34a, 34a are axially formed on the outer surface of the bearing 34, and the grooves 34a, 34a are formed.
The load pressure of the power steering device PS is guided to the movable iron core 32 side via a. The load pressure introduced to the movable iron core 32 side acts on both pressure receiving surfaces 32a and 32b of the movable iron core 32 through the gap s. Therefore, the force applied to the movable iron core 32 by the load pressure is canceled and the movement of the diaphragm member 31 is not adversely affected.

On the other hand, a spring 22 is provided between the rear end surface 31a of the diaphragm member 31 and the adjuster 29, and the spring force of the spring 22 exerts a force on the diaphragm member 31 in a direction to reduce the opening of the variable diaphragm V. I'm giving. However, due to the spring force of the spring 22, the surface 32a of the movable iron core 32 is
However, when it is pressed against the surface 34b of the bearing 34, the opening of the variable aperture V is accurately maintained at a predetermined opening. That is, in this embodiment, the variable aperture is not completely closed as in the conventional example. The spring force of the spring 22 can be adjusted by the adjuster 29, which is the same as the conventional one.

Next, the operation of this embodiment will be described. For example, when the proportional solenoid S is de-energized, the diaphragm member 31 is moved by the spring force of the spring 22.
2 is pressed against the bearing 34 and stopped. At this time, since the variable throttle V is maintained at a predetermined opening, a flow rate according to this opening is supplied to the power steering device PS as a standby flow rate. That is, in this example,
It is possible to supply a predetermined standby flow rate to the power steering device PS via the variable throttle V without specially providing a fixed throttle as in the conventional case.

When the proportional solenoid S is excited, the movable iron core 32 is attracted and the diaphragm member 31 moves to the right in the drawing. And the attraction force by the proportional solenoid S,
At the position where the spring force of the spring 22 is balanced, the diaphragm member 3
1 stops, and the stop position determines the opening of the variable aperture V. When the opening of the variable throttle V is determined in this way, the flow rate according to the opening is supplied to the power steering device PS.

According to the above embodiment, the diaphragm 34 is slidably supported by the bearing 34. The bearing 34 is smaller and lighter than the conventional connecting member 4. Thus, machining the sliding hole 35 in the light and small bearing 32 is far easier to process than machining the sliding hole 13 in the heavy and large connecting member 4. As described above, the processing cost is lower in this embodiment than in the conventional example because the processing work is easy.

Further, according to this embodiment, even when the proportional solenoid S is in the non-excited state, the variable throttle V can accurately maintain a predetermined opening, so that the fixed throttle as in the prior art is specially designed. Even if it is not provided, the standby flow rate can be supplied to the power steering device PS. Therefore, in this embodiment, the processing cost can be reduced because the fixed aperture need not be specially formed.

Further, according to this embodiment, the bearing 34
The standby flow rate can be freely adjusted simply by moving the mounting position of in the axial direction. Therefore, in this example,
When changing the standby flow rate, the parts of the same standard can be used as they are. In this way, the parts of the same standard can be used as they are, so that the cost for mass production can be kept low. Furthermore, the diaphragm member 31 and the movable iron core 32 are incorporated in the diaphragm opening member 30, and the variable diaphragm V is arranged in the diaphragm opening member 30.
Since this is formed, the axial length of the device can be made shorter than that of the conventional example. Moreover, when the differential pressure before and after the variable throttle V is applied to the throttle member 31, the opening of the variable throttle V is increased, so that the opening of the variable throttle V is controlled even if the thrust of the proportional solenoid S is small. be able to. Therefore, the proportional solenoid S can also be downsized.

In the above-mentioned conventional example, the load pressure is set to the back pressure chamber 2
In order to lead to 7, the internal passage 26
Had to form. On the other hand, in the above embodiment, since the load pressure can be guided to the movable iron core 32 side through the groove 34a formed in the bearing 34, the throttle member 3
No need to drill holes in 1. Therefore, the working cost can be further reduced in this embodiment.

[0031]

According to the first aspect of the invention, since the diaphragm member is configured to be supported by the bearing, it suffices to process the hole with this bearing. A component such as the bearing can be made lighter and smaller, and it is easier to perform a working operation by forming a hole in such a light and small component. Thus, the processing cost can be reduced because the processing work is easy.

Further, since the movement of the movable iron core is regulated by the bearing so that the variable throttle V is not completely closed even when the solenoid is in the non-excited state, a predetermined flow rate is supplied to the actuator side through the variable throttle. Can be supplied. Therefore, it is not necessary to form a special flow path in order to maintain the standby state or to obtain fail-safe, and the processing cost can be reduced accordingly.

Further, when the bearing is fixed, the standby flow rate can be freely set by adjusting the axial position of the bearing. Therefore, the exact same bearing can be used as it is. Since the same bearing can be used as it is, productivity can be increased.

According to the second aspect of the invention, since the load pressure is also guided to the movable iron core side by the groove portion formed in the bearing, a hole for guiding the load pressure is purposely formed in the throttle member or the movable iron core. You don't have to. Therefore, the processing cost can be further reduced.

According to the third aspect of the invention, when the differential pressure before and after the variable throttle acts on the throttle member, the valve portion and the seat portion are opposed to each other so that the opening of the variable throttle becomes large. It's small enough. Therefore, the solenoid can be downsized accordingly. According to the fourth invention, since the diaphragm member and the movable iron core are incorporated in the diaphragm opening member and the variable diaphragm is formed in the diaphragm opening member, the axial length of the entire apparatus is larger than that of the conventional example. The length can be shortened.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of an apparatus according to an embodiment.

FIG. 2 is a cross-sectional view of a conventional device.

[Explanation of symbols]

2 pump ports 3 tank ports 6 Actuator port 7 Spool hole 8 spools 9 control room 10 pilot room 11 spring 22 spring 30 Aperture opening member 31 diaphragm member 32 movable iron core 34 bearings 34a groove 36 valve 37 Seat V variable aperture h housing S proportional solenoid

Front page continuation (58) Fields surveyed (Int.Cl. ⁷ , DB name) B62D 5/07

Claims (4)

(57) [Claims] 1. A housing in which a pump port and an actuator port are formed, a spool hole formed in the housing, a spool slidably incorporated in the spool hole, and one end surface side of the spool. , A control chamber that is in constant communication with the pump port, a pilot chamber that is defined on the other end surface side of the spool, and when the spool moves due to the pressure action of these control chamber and pilot chamber, it communicates with the control chamber and the spool A tank port whose communication opening with the control chamber is controlled according to the amount of movement of the control port, a throttle opening member having a flow passage that connects the pump port and the actuator port, and a flow passage of the throttle opening member. A variable aperture and a solenoid that adjusts the opening of the variable aperture are provided. The valve section is provided at the end, and the valve section and the seat section provided in the throttle opening member together form a variable throttle, while the movable iron core of the solenoid is provided on the rear end side of the throttle member and In a flow rate control device in which a spring force of a spring is applied from the iron core side to apply a force in a direction to reduce the opening of a variable throttle to a throttle member, a bearing is incorporated in the throttle opening member and While supporting the diaphragm member slidably,
A flow rate control device characterized in that a variable throttle maintains a predetermined opening when a movable iron core comes into contact with one end of the bearing. 2. The flow rate control device according to claim 1, wherein a groove is formed on the outer circumference of the bearing member, and the load pressure is guided to the movable iron core side through the groove. 3. The valve portion and the seat portion are opposed to each other so that the opening of the variable throttle is increased when a differential pressure before and after the variable throttle is applied to the throttle member. Flow control device. 4. The diaphragm opening member has a movable iron core of a solenoid and a diaphragm member incorporated therein, and a seat portion provided inside thereof and a valve portion of the diaphragm member constitute a variable diaphragm. The flow control device according to any one of claims 1 to 3.