JPS6026870A - Linear solenoid valve - Google Patents

Abstract

PURPOSE:To make the opening of a valve modifiable according to feed pressure, by installing a magnetic resistance control body in position between a cover member being set up so as to surround the outer circumference of a solenoid and a yoke installed in the inner circumference of the solenoid, while shifting this control body to some extent according to hydraulic pressure at the high pressure side. CONSTITUTION:In case where this valve is applied to a speed responsive type power steering device, when a control current commensurate to a car speed is impressed on a solenoid 29, such magnetic flux as passing through a cover 30, a valve body 21, a spool 27, a yoke 26, a magnetic resistance control body 35 and an air gap 38 is formed up. With this constitution, the spool 27 is displaced to some extent against a spring 33 by dint of magnetic attraction whereby a slit 27a is opened to a port 22b and a bypass passage is formed between ports 20a and 20b. At this time, when a steering wheel is suddenly operated, with this operation, pressure in the hydraulic fluid given by way of a through hole 27b goes up, causing the magnetic resistance control body 35 to be raised against a spring 37, and magnetic resistance in the air gap 38 grows large, thus the spool 27 is made to go down.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention linearly controls pressure fluid flowing from a high pressure side flow path to a low pressure side flow path in accordance with a control current applied to a solenoid. Is it related to lubrication, especially controlling the steering force according to the vehicle speed? This invention relates to a near solenoid valve suitable for use in a vehicle speed sensitive power steering system.

<Prior Art> Generally, in a vehicle equipped with a vehicle speed-sensitive power steering device, the node 71. In order to compensate for the problem of light steering becoming too light, a measure has been taken to pass the pressure oil supplied to the power cylinder of the power steering device to the low pressure side during high speed driving, thereby reducing the steering gain. ing. However, when driving at high speed, the sudden
In the case of turning the steering wheel, the steering gain is reduced due to the bypass control of the pressure oil, making the steering wheel operation heavier, which impedes steering followability and gives the driver a sense of anxiety. To solve this problem, it is possible to reduce the amount of bypass to the low pressure side in response to a sudden operation of the handle, but with conventional linear solenoid half valves, the opening degree of the valve is changed according to the supply pressure. This kind of control was not possible because there was no function to do so.

<Objective of the Invention> An object of the present invention is to provide a near solenoid 1-half in which the Hartz opening degree can be completely changed in response to supply pressure.

<Structure of the Invention> A magnetic resistance control body that changes the magnetic resistance of the air gap interposed in the magnetic path by axial movement is provided between the cover part disposed so as to surround the outer periphery of the solenoid and the yoke. Fluid on the high pressure side of the boat is applied to an end face perpendicular to the moving direction of the magnetic resistance control body to move the magnetic resistance control body in accordance with the fluid pressure on the high pressure side, and further, the magnetic resistance control body is moved by the fluid pressure due to the fluid pressure. Each time a control spring is provided that applies a pressing force to the magnetic resistance control body in a direction opposite to the direction in which the resistance control body moves, 1 is defined as 1.

<Example> Embodiments of the present invention will be described below with reference to the drawings.

In FIG. 1, 10 indicates a power steering device, and this υj
The power steering device IO includes a valve bousing 11 housing a servo valve, and a steering wheel 1 for the drying vehicle @19. V link mechanism 18
When a servo valve is actuated by operating a steering handle 17, a supply pipe 15 is supplied from a steering pump 16. A constant flow of pressure oil supplied through the power cylinder 12 is distributed to one chamber Q of the power cylinder 12, and the oil in the other chamber of the power cylinder 12 is discharged to the reservoir tank 13 through the discharge pipe 14. In such a configuration,
IJ near solenoid 1 according to the present invention: The boats 20a and 20b of the valve 20 are connected to the supply pipe 15 and the discharge pipe 4 via branch pipes 152 and 14a, and the same knee solenoid valve 20 is connected to the solenoid F described later. is applied from the electric control circuit 40 depending on the vehicle speed.

In addition, the electric control circuit 40 detects the rotational speed of the propeller shaft of the 1-transmission 43.
+! 341, and outputs a current according to the vehicle speed.

Figure 2 shows the knee 7 solenoid valve 20 shown in Figure 1.
This figure shows in detail the internal structure of the valve body 21, which is made of a magnetic material and is fitted liquid-tightly into the large diameter part of the through hole 22a provided in the J member 22, which is fixed to the -RII of the vehicle body. The combined cylindrical protrusion 21a'ii'' is the same as this protrusion 21a.
A radial boat 22b is formed which communicates with a boat 20b connected to the second branch pipe 14a, and the other end is formed with an inner hole 2 bored vertically through the center of the valve body 21.
It opens in the peripheral wall of 1b. Further, a union 24 is screwed onto the lower end of the protruding portion 21a, and the small diameter end of the union 24 is fluid-tightly fitted into the small diameter portion of the through hole 22a. The union 24 is provided with a bow h2 (la) connected to the branch WI5a, and the upper end of the boat 20a opens into the inner hole 21b. On the upper part of the sleeve 25 made of a non-magnetic material fixed by
A spacer ring 23 made of a non-magnetic material is disposed between the lower end of the guide hole 26 and the protrusion of the valve body 21. A solenoid 29 wound around a bobbin 28 made of a non-magnetic material is provided on the outer periphery of the sleeve 25 and the guide hole 26.
A cover 30 made of a magnetic material is provided on the outer periphery of the valve body 21 at its lower end.

On the other hand, a control spool 27 made of a magnetic material is slidably inserted into the inner hole 21b of the valve body 21, and the upper end of the control spool 27 is movable in a shaft that is screwed into the overhanging portion 31 of the cover 30. A spring made of stainless steel is compressed between the retainer 32 and the spring 33.
Normally, the control spool 27 is connected to the union 24 depending on the
It is held at the lower end that touches the.

Bypass slits 27a, 27a cut out in the radial direction are installed at a predetermined length in the axial direction at the lower end of the control spool 27, and these slits 1127a, 27a
a is the boat 2 when the control spool 27 is at the lower end position.
0a and baud 1-20b, and spool 2
Due to the upward displacement of 7, the boat 20a and the boat 1-20b
A bypass passage is formed between them. Furthermore, a through hole 27b is bored in the center of the control spool 27 to allow the fluid pressure of the boat 20a, which is the high-pressure side, to flow through the second part of the control spool 27.

Further, a guide hole 26a is formed in the center of the cork 26 to pass through the yoke 26 uniformly.
A magnetic resistance control body 35, which has a cylindrical shape and guides and supports the retainer 32 by its inner periphery, is guided so as to be axially movable. The upper end surface of this magnetic resistance control body 35 and the overhanging portion 31
A control spring 37 that pushes the magnetic resistance control body 35 downward is compressed between the magnetic resistance control body 35 and an overhang portion 26bJ formed at the lower part of the guide hole 26a.
A radial notch 36a is formed at the upper end of the stopper ring 36, which is made of a non-magnetic material and is disposed between the lower end surface of the stopper ring 36 and the lower end surface of the stopper ring 36. It acts on the lower end surface of the magnetic resistance control body 35.

Further, the two wheels of the magnetic resistance control body 35 have a radially outer side.
1. A protruding flange portion 35a is formed, and its outer circumferential surface faces the inner circumferential surface of the hole 30a drilled in the upper wall of the cover 30 with a minute gap 38, which allows magnetic resistance control. When the body 35 moves to the second part, the flange part 35a and the hole 3
The amount of overlap with 0a increases, and the magnetic resistance produced by the air gap 38 increases.

The magnetic flux generated by solenoid F 29 is
0, because it flows through a loop-shaped magnetic path formed by the valve body 21, control spool 27, yoke 26, and air gap 38, and the attractive force acting on the control spool 27 is inversely proportional to the magnetic resistance in this loop-shaped magnetic path. , magnetic resistance control body 3
5 increases the magnetic reluctance of the air gap 38, the attractive force acting on the control spool 27 decreases, causing the control spool 27 to move in the closing direction.

The solenoid valve 2o configured as described above is configured such that the electric control circuit 40 supplies a control current according to the vehicle speed to the solenoid valve 2o.
9, a magnetic flux is formed that passes through the solenoid 129, cover 30, valve body 21, spool 27, cloth 33, yoke 26, magnetoresistive control body 35, and the conductive layer, thereby causing the control spool Attractive force in the direction of the arrow is applied to 27 in proportion to the current applied to the two solenoids. However, if the vehicle speed is lower than the predetermined speed, the control spool 27 will not be displaced by the J force of the spring 33, and both boats 20a, which communicate with the left and right compartments of the power cylinder 12 via branch pipes 15a and 14a. When the steering wheel 17 is operated, the discharge pressure of the pump 16 increases in accordance with the road resistance due to the action of the servo valve, and the appropriate pressure is increased by the operation of the power cylinder 12. The steering force is (
Layered.

When the vehicle speed exceeds a predetermined speed, the spool 2 is struck by the suction force of the solenoid 29 or the same force of the spring 33.
7 begins to be displaced. As a result, the slit 27a is opened in the boat 22b, and a bypass passage is formed between both the boats 1 and 20a and the boat 20a. Mata, Sri] I-27
Opening 1-21 of a (11) Since it changes linearly according to the current applied to solenoid 29,
The bypass flow rate bypassed between a and 20b increases as the vehicle speed increases, and as a result, the C steering force varies linearly with the vehicle speed, resulting in vehicle speed stability.

When the lff1 rudder handle 17 is rapidly operated during the above-mentioned displacement of the spool 27, the discharge pressure of the pump 19 rapidly increases due to the action of the servo valve in response to the sudden steering operation, and the discharge pressure of the pump 19 increases rapidly from the bow 120a. Due to the action of the actuating surface 15 extending through the hole 27b, the magnetic resistance control body 35 overcomes the biasing force of the control spring 37 and is displaced upward. For this reason, the magnetic resistance of the air gap 38 increases, the attraction force of the resonoid 29 acting on the control spool 27 decreases, and the control spool 27 is displaced downward, causing both boats 20
Decrease the bypass flow between a and 20b.

As a result, when the steering wheel is suddenly operated while traveling at high speed, the decrease in steering gain due to the bypass control of the pressure oil is suppressed, so that the steering wheel does not become heavy and the steering wheel can be operated easily.

<Effects of the Invention> As described above, in the present invention, a magnetic resistance control body capable of changing the magnetic resistance of a magnetic path formed so as to surround the solenoid by axial movement is provided between the yoke and a portion of the cover. When the pressure on the high-pressure side boat 1 increases, the magnetic resistance control body is moved in the direction in which the magnetic resistance of the magnetic path increases. It becomes possible to control the opening degree of the valve according to the rise.

Therefore, by applying the glue near solenoid valve of the present invention to a vehicle speed response control system that bypasses the pressure oil supplied to the power cylinder to the low-pressure side, it is possible to avoid sudden steering during high-speed driving without the need for a special additional circuit. It is possible to control the increase in the gain in the case where one operation is performed, and it is possible to obtain a steering force of J'fh.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram showing an outline of a vehicle speed sensitive power steering device using a linear solenoid valve according to the present invention, and FIG. 2 is a cross-sectional view of the near solenoid valve shown in FIG. 1. 20a, 20b...Beau 1~. 21...Knoll body, 22...Installation department publication, 26...Yoke, 27...
- Control spool, 27b... Through hole, 29... Solenoid, 30... Cover, 33° 37... Spring, 35... Magnetic resistance control body, 38... Gap. Patent applicant Yutaka 1] Koki Co., Ltd.

Claims (1)

[Claims] (]) A valve body, a solenoid to which a control current is applied, a yoke provided on the inner periphery of the solenoid, and a yoke that is slidably fitted into the valve body opposite one end of the yoke and is connected to the solenoid. A near solenoid valve includes a spool that controls the flow rate of fluid flowing between a pair of ports by displacing in response to an applied current, and a spring that biases this spool in the closing direction. A cover member forming a magnetic path is arranged to surround the outer periphery of the solenoid, and the magnetic resistance of the air gap interposed in the magnetic path by axial movement between the cover member and the yoke is Change the
A magnetic resistance control body is provided, and fluid on the high pressure side of the pair of boats is applied to an end face perpendicular to a moving direction of the magnetic resistance control body to move the magnetic resistance control body in accordance with the fluid pressure on the high pressure side. The near solenoid valve further comprises a control spring that applies a pressing force to the magnetic resistance control body in a direction opposite to the direction in which the magnetic resistance control body moves due to the fluid pressure.