JPH0144871Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Field of Application) The present invention relates to an electromagnetic proportional control valve used for controlling the steering force of a power steering device.

(Prior art) This type of electromagnetic proportional control valve displaces the control spool in the axial direction against the repulsive force of a spring by the attractive force generated by the current applied to the solenoid.
It proportionally controls the supply of pressurized fluid to fluid-operated equipment, and in such electromagnetic proportional control valves, the suction force on the control spool tends to increase rapidly just before it comes into contact with the yoke, and as a result, the control spool becomes attached to the yoke. It is attracted and cannot be removed, resulting in malfunction.

Furthermore, in this electromagnetic proportional control valve, the control spool vibrates due to pressure fluctuations in the hydraulic power source or pressure fluctuations due to noise in the applied current, which may cause abnormal noise. Particularly when this electromagnetic proportional control valve is applied to a vehicle speed-sensitive power steering system, there is a problem in that the occurrence of the above-mentioned vibration changes the bypass flow rate and fluctuates the steering force, causing discomfort to the driver. There is.

In order to deal with such problems, conventionally a stopper has been provided to limit the stroke of the control spool, and an orifice has been provided to prevent vibration of the control spool.

However, in the conventional device described above, the stopper is provided on the yoke side, the orifice is provided on the control spool side, and both are constructed from separate members, which increases the number of parts, resulting in high costs and increased assembly man-hours. There were flaws.

(Purpose of the invention) The present invention was made in order to eliminate the above-mentioned drawbacks of the conventional technology, and its purpose is to create an electromagnetic proportional control valve that has a small number of parts, is low cost, and can be assembled with a small number of man-hours. The goal is to provide the following.

(Structure of the invention) The present invention has been made to achieve the above object, and is characterized in that the washer that guides and supports the spring is made of a non-magnetic material, and is provided with an orifice and an abutment part. It is.

(Example) Hereinafter, the present invention will be explained based on the drawings. The drawings show an embodiment of the electromagnetic proportional control valve according to the present invention. This electromagnetic proportional control valve (hereinafter simply referred to as a control valve) is used in a vehicle speed-sensitive power steering system, and connects the fluid discharge pipe from the fluid pump to the power cylinder of the power steering system and the power supply. It is used by being interposed between the fluid discharge pipe from the cylinder to the reservoir tank.

The valve body 10 of this control valve includes a valve sleeve 11 made of a magnetic material, a support sleeve 12 made of a non-magnetic material fixed to the outer periphery of the valve sleeve 11 by brazing or the like, and fixedly fitted into the support sleeve 12. Guide sleeve 1 made of non-magnetic material
3, and an end sleeve 14 made of a non-magnetic material that is fitted and fixed to the valve sleeve 11.

The valve body 10 is attached to the attachment member 21 so that the end sleeve 14 is fitted in a large diameter inner hole 21a provided in the attachment member 21 in a liquid-tight manner. The mounting member 21 has two ports 21b, 21
One port 21b is connected to a fluid supply line (not shown) from the fluid pump to the power cylinder via a branch pipe, and the other port 21c is connected to a fluid discharge line (not shown) from the power cylinder to the reservoir tank. Connected to the pipeline via a branch pipe. Further, these both ports 21b and 21c are the radial port 14a provided in the end sleeve 14.
It also communicates through the large-diameter inner hole 21a.

On the other hand, the valve sleeve 11 and the guide sleeve 1
A control spool 30 is slidably inserted into an inner hole 15 of the valve body 10 formed by the inner holes of the valve body 10 and the end sleeve 14 . Further, a stepped sleeve 23 made of a magnetic material is integrally fixed in the inner hole at the outer end of the support sleeve 12 by brazing or the like. A solenoid 25 wound around a bobbin 24 made of a non-magnetic material is provided on the outer periphery of the stepped sleeve 23 and the support sleeve 12.
Further, a yoke 26 made of a magnetic material is screwed into the inner hole of the stepped sleeve 23 in a liquid-tight manner. The yoke 26 includes an inner hole 26a and a screw hole 26b, and a retainer 27 is fitted into the inner hole 26a in a fluid-tight and slidable manner.

The control spool 30 includes a first spool 31 made of a magnetic material and a second spool 32 made of a magnetic material.
and a partition member 33 made of a non-magnetic material that partitions these spools 31, 31 from each other. First,
A through hole 31b and a mounting hole 32d are respectively formed in the axial direction of the second spools 31 and 32, and a first washer 34 made of a non-magnetic material is fitted and fixed to the outer end of the through hole 31b. A second washer 35 is fitted and fixed in the hole 32d. The second washer 35 guides and holds the first compression spring 22 between it and the bottom of the large diameter inner hole 21a of the mounting member 21, and the first washer 34 guides the second compression spring 28 between it and the retainer 27. The position of the control spool 30 within the inner hole 15 of the valve body 10 is supported in a balanced manner by both springs.

Also, the first washer 34, which is a main component of the present invention,
is made of a non-magnetic material, and has a flange-like contact portion 34b formed on its outer periphery. This flange-shaped contact portion 34b contacts the lower end of the yoke 26 when the control spool 30 is displaced upward by a predetermined amount, and this contact prevents the control spool 30 from upward stroke. This prevents the adhesion phenomenon with the yoke 26 and the resulting malfunction.

Furthermore, orifices 34 are provided in the first and second washers 34, 35, the second spool 32, and the partition member 33.
a, 35a, 32a, and 33a are formed.
These orifices 34a, 35a, 32a, 33a
is the through hole 3 due to the axial displacement of the control spool 30.
1b, the control spool 30, and the gap between the yoke 26, the fluid flowing between the control spool 30 and the yoke 26 is restricted, and the control spool 30
to prevent vibration.

Note that 29 is connected to the first and second through the retainer 27.
An adjustment screw 42 is used to adjust the biasing force of the compression springs 22 and 28, and a fixing bolt 4 is attached to the outer end of the yoke 26.
This is a cover fixed by 1.

In the control valve configured in this manner, when a control current corresponding to the vehicle speed is applied to the solenoid 25 from an electric control circuit (not shown), the flow from the solenoid 25 to the cover 42, the valve sleeve 11 of the valve body 10, and the valve sleeve 11 of the control spool 30 is applied. A magnetic flux is formed passing through the 1 spool 31, the yoke 26, the stepped sleeve 23, the cover 42, and the solenoid 25, and thereby an attractive force in the direction of the arrow proportional to the current applied to the solenoid 25 acts on the control spool 30.

As a result, the second spool 32 is displaced in the direction of the arrow, the ports 21b and 21c are brought into communication, and a bypass passage that detours around the power cylinder is formed between the ports 21b and 21c. Further, since the opening area of the bypass passage changes linearly according to the current applied to the solenoid 25, both ports 21b and 2
The bypass flow rate of the pressure fluid bypassed between 1c increases as the vehicle speed increases, and as a result, the steering force changes linearly in accordance with the vehicle speed, resulting in high-speed stability.

When the control spool 30 is displaced in this manner, the fluid in the inner hole 15 of the valve body 10 and the inner hole 21a of the mounting member 21 flows through the orifices 34a, 35a of the washers 34, 35, and the control spool 30 This produces a damping effect.
Therefore, the control spool 30 operates extremely smoothly.

(Effects of the invention) As detailed above, the electromagnetic proportional control valve of the invention has a configuration in which the washer that guides and supports the spring is made of a non-magnetic material, and is provided with an orifice and a contact part, so that control Although it has a spool damping function and a yoke adsorption prevention function, it has the advantage of having a small number of parts and can be assembled at low cost and with a small number of man-hours.

In this embodiment, an example in which the present invention is applied to an electromagnetic proportional control valve employed in a vehicle speed-sensitive power steering system is shown. It can be applied to various electromagnetic proportional control valves that proportionally control the supply of pressure fluid to equipment.

[Brief explanation of the drawing]

The drawing is a longitudinal sectional view of an electromagnetic proportional control valve showing an embodiment of the present invention. Explanation of symbols, 10... Valve body, 11... Valve sleeve, 13... Guide sleeve, 14...
...End sleeve, 14a...Port, 15...
Inner hole, 21...Mounting member, 21b, 21c...Port, 25...Solenoid, 26...Yoke, 2
8... Compression spring, 30... Control spool,
31b...Through hole, 34...Washer, 34a...Orifice, 34b...Abutment part.

Claims (1)

[Scope of utility model registration request] A valve body, a solenoid to which a control current is applied, a yoke provided on the inner periphery of the solenoid, and a current applied to the solenoid that is slidably inserted into the valve body opposite one end of the yoke. In an electromagnetic proportional control valve equipped with a control spool that is attracted in accordance with an orifice that communicates a through hole in the axial direction of the control spool with a gap between the control spool and the yoke; and an abutment part that comes into contact with the yoke to regulate the stroke of the control spool. An electromagnetic proportional control valve characterized by forming: