JPH04253204A - Spool type pressure control valve - Google Patents

Abstract

PURPOSE:To prevent a spool from being oscillated by over sliding and to exactly control liquid pressure at a set value by preventing the spool of the spool type pressure control valve from being axially over slid by control force. CONSTITUTION:One edge side fluid chamber R of a spool 12 at an inner hole 11a of a housing 11 is communicated to a reserver 26 by a first communicating duct 28a and a second communicating duct 28b equipped with an orifice 28c, and the first communicating duct 28a is made close to one edge side of the spool 12 rather than the second communicating duct 28b. Fluid in the fluid chamber R is discharged from the first communicating duct 28a at the beginning of sliding the spool 12 and from the second communicating duct 28b when the spool 12 is slid for a prescribed amount.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a spool type pressure control valve.

0002

[Prior Art] As shown in the specification and drawings of Japanese Patent Application No. 2-182932 filed by the present applicant, a spool type pressure control valve has an inner hole extending in the axial direction and A housing having a high pressure port, a low pressure port, and a control pressure port located at a predetermined interval in the axial direction and communicating with the inner hole, and slidable in the inner hole of the housing in a liquid-tight manner and in the axial direction. A spool that is fitted and slid in the axial direction selectively communicates the control pressure port with the low pressure port and the high pressure port; a pressing force generating means that presses the spool in a direction to cut off communication between the control pressure port and the high pressure port by the action of pressure, and a driving force located at the other end of the spool and proportional to the excitation current to the solenoid. There is a spool-type pressure control valve that includes a control force applying means for generating a control force and applying a control force to the spool that counteracts the pressing force.

In this type of spool-type pressure control valve, the pressure chamber communicates with a reservoir containing fluid through a communication pipe or the like, and when the control valve is not operated, the spool is in a set return position. Communication between the control pressure port and the high pressure port is cut off, and the control pressure port and the low pressure port are communicated with each other. When the solenoid of the control force applying means is energized in such a state, the control force applying means generates a driving force proportional to the excitation current to the solenoid to counteract the pressing force from the pressing force generating means against the spool. Gives control. Therefore, the spool slides toward the - end side with a control force proportional to the excitation current of the solenoid, cutting off communication between the control pressure port and the low pressure port, and communicating the control pressure port and the high pressure port. At this time, the fluid in the fluid chamber is removed to the reservoir side by the spool.

As a result, high fluid pressure is applied to the control pressure port from the high pressure port side, and the same fluid pressure is applied to the pressing force generating means to generate a pressing force proportional to the fluid pressure. This pressing force is applied to the spool as an opposing force to the above control force, and the spool stops when these control forces and pressing force are balanced, and the fluid pressure on the control pressure port side is proportional to the excitation current. control to a predetermined pressure.

[0005]

[Problem to be Solved by the Invention] In this way, in this pressure control valve, when the pressure of the control pressure port is increased, the control force of the control force applying means is used to move the spool to the axis while removing the fluid at approximately atmospheric pressure in the fluid chamber. Since the spool is slid in a direction, the spool may slide for a moment too much, and this excessive sliding causes the spool to vibrate. When vibration occurs in the spool, there is a possibility that the fluid pressure on the control pressure port side cannot be accurately controlled to a set value. Therefore, an object of the present invention is to prevent the generation of vibration in the spool due to excessive sliding in the axial direction of the spool in this type of spool type pressure control valve.

[0006]

[Means for Solving the Problems] The present invention has an inner hole extending in the axial direction, and has a high pressure port, a low pressure port, and a control pressure port located at a predetermined interval in the axial direction and communicating with the inner hole. a housing; and a spool that is fluid-tightly and slidably inserted into the inner hole of the housing and selectively communicates the control pressure port with the low pressure port and the high pressure port by sliding in the axial direction. and a pressing force is generated that presses the spool in the direction of cutting off communication between the control pressure port and the high pressure port by the action of the fluid pressure of the control pressure port facing into the fluid chamber formed on the negative end side of the spool. and control force applying means located at the other end of the spool and generating a driving force proportional to the excitation current to the solenoid to apply a control force to the spool that counters the pressing force. It is a spool type pressure control valve,
The fluid chamber includes a first communication pipe and a second fluid chamber in which an oris is arranged.
communicates with the fluid reservoir through a communicating pipeline, and among these communicating pipelines, the first communicating pipeline is displaced toward the -end side of the spool compared to the second communicating pipeline, so that the pressure is increased. It is characterized by opening into the chamber.

[0007]

In the spool type pressure control valve having such a structure, the spool slides in the axial direction by the control force of the control force applying means, firstly communication between the control pressure port and the low pressure port is cut off, and the spool When further slides, the control pressure port communicates with the high pressure port, and the hydraulic pressure on the control pressure port side is controlled in proportion to the excitation current. In this case, as the spool slides in the axial direction, the fluid in the fluid chamber flows into the first fluid chamber where the orifice is not provided at the beginning of the spool sliding.
The fluid is mainly discharged from the first communication pipe, and when it slides immediately before the communication between the control pressure port and the high pressure port, the communication between the first communication pipe and the fluid chamber is cut off, and an orifice is provided. It is discharged from the second communication pipe. As a result,
The sliding movement of the spool until just before it communicates with the control pressure port and the high pressure port is smooth because there is little resistance from the fluid in the fluid chamber against the spool, and after that, the spool slides smoothly due to the resistance caused by the fluid in the fluid chamber. Excessive sliding is prevented.

[0008]

[Effects of the Invention] Therefore, the spool type pressure control valve has good responsiveness during operation, and
No vibration occurs in the spool, and the hydraulic pressure on the control pressure port side can be accurately controlled to a set value.

[0009]

[Embodiments] Hereinafter, embodiments of the present invention will be explained based on the drawings. Fig. 1 shows a spool type pressure control valve 1 according to the present invention.
0 is shown. The pressure control valve 10 is used in a hydraulic brake system for an automobile, and is incorporated into the brake system as shown in FIG. The brake system includes a master cylinder 21 and a change valve 22.
A hydraulic system leading to the wheel cylinder 23 of each wheel via the accumulator 24, and the pressure control valve 10 according to this embodiment.
There are two systems: a hydraulic pressure path and a hydraulic pressure path that passes through the change valve 22 and reaches the hole cylinder 23 of each wheel. Note that the change valve 22 and the pressure control valve 10 are connected to each wheel cylinder 2.
3, but only one of each is shown in the figure. In the accumulator 24, brake fluid in a reservoir 26 is always stored within a certain hydraulic pressure range by a fluid pump 25, and the brake fluid is applied to the high pressure port side of a pressure control valve 10, which will be described later. In addition, in this embodiment, the brake fluid corresponds to the fluid of the present invention.

In this brake system, the pedal force on the brake pedal 27 is detected by the pedal force sensor 31, and
The detection signal is input to the controller 32. The controller 32 calculates an excitation current for the pressure control valve 10 based on the pedal force detection signal and the acceleration detection signal input from the acceleration sensor 33, and sends a command signal of the excitation current to the drive circuit 34.
to energize the solenoid of the pressure control valve 10. Thereby, brake fluid pressure corresponding to the depression force of the brake pedal 27 is applied to the wheel cylinder 23, and each wheel is appropriately braked.

Furthermore, when an abnormality occurs in the hydraulic system such as the pressure control valve 10, brake hydraulic pressure is applied from the master cylinder 21 to the wheel cylinder 23 according to the depression force of the brake pedal 27 by the switching action of the change valve 22. to compensate for abnormalities in the hydraulic system.

As shown in FIG. 1, the pressure control valve 10 includes a housing 11, a spool 12, and a pressing force generating means 1.
0a and control force applying means 10b. The pressing force generating means 10a is composed of a reaction force piston 13 and a compression spring 14, and the control force applying means 10b is composed of an operating piston 15, a solenoid 16, and a yoke 1.
7 and a magnet 18.

The housing 11 has an inner bore 11 extending in the axial direction.
a, an accommodation hole 11b of the pressing force generating means 10a located coaxially at one end of the inner hole 11a, and an accommodation chamber 11c of the control force applying means 10b coaxially located at the other end of the inner hole 11a; and a control pressure port 11d, a high pressure port 11e, and each low pressure port 11f, 11g, 11
h. Each of these ports 11d to 11h is located along the inner hole 11a at a predetermined interval in the axial direction,
Each of them opens into the inner hole 11a. In addition, the accommodation hole 11
A branch port 11i opens to b, and a drain port 11j opens to the accommodation chamber 11c.

In the housing 11, the control pressure port 11d is connected to the wheel cylinder 23, the high pressure port 11e is connected to the accumulator 24, and the low pressure ports 11f, 11g, and 11h are connected to the reservoir 26. In addition, the branch port 11i is the control pressure port 11
d, and the drain port 11j is connected to the reservoir 26
It is connected to the.

The spool 12 has a cylindrical shape as shown in FIGS. 1 and 2, and has an annular groove 12a formed on its outer periphery that extends for a predetermined length in the axial direction, and has a liquid-tight seal in the inner hole 11a of the housing 11. The inner hole 11a is fitted into the inner hole 11a so as to be slidable in the axial direction, and the inside of the inner hole 11a is partitioned into a fluid chamber R at the other end of the spool 12. In this spool 12, the annular groove 12a connects the control pressure port 11d to the high pressure port 11.
e or has a length that selectively communicates with the first low pressure port 11f, and when sliding in the axial direction, after the communication between the control port 11d and the first low pressure port 11f is cut off, the control port 11d slides a predetermined amount and becomes the control pressure port. 11d is formed to have a length that communicates with the high pressure port 11e.

The reaction force piston 13 constituting the pressing force generating means 10a is slidably inserted into the accommodation hole 11b and faces the inside of the fluid chamber R.
Forced to the side. Reaction force piston 1 in accommodation hole 11b
A branch port 11i is opened on the end side of 3. As a result, the reaction piston 13 is urged by the compression spring 14 and the control fluid pressure applied from the branch port 11i, and comes into elastic contact with the other end of the spool 12.

A pair of second and third low pressure ports 11g and 11h formed in the housing 11 open into the fluid chamber R of the inner hole 11a. Each low pressure port 11g, 11
In h, as shown in FIGS. 1 and 2, the second low pressure port 11g is located close to the -end side of the spool 10,
Further, the third low pressure port 11h is located at a predetermined distance from the second low pressure port 11g in the direction away from the negative end of the spool 12. The second low pressure port 11g communicates with the reservoir 26 via the first communication pipe 28a, and the third
The low pressure port 11h communicates with the reservoir 26 via the second communication conduit 28b. Of these two communicating pipes, the first
The communication pipeline 28a corresponds to the first communication pipeline of the present invention, and the second communication pipeline 28b corresponds to the second communication pipeline of the present invention, and the second communication pipeline 28b has an orifice 28c. is installed.

Yoke 1 constituting control force applying means 10b
7 is fitted into the storage chamber 11c, and an annular magnet 18 is fixed to the outer periphery of the intermediate portion in the axial direction. The actuating piston 15 is fitted coaxially into the yoke 17 so as to be able to slide in the axial direction, and its lower end abuts the other end of the spool 12 to receive the spool 12. The actuating piston 15 has an annular solenoid 16 on the other end side of the cylinder, and is located at the retreating end shown in FIG. 1 when the solenoid 16 is not energized.

In a brake system equipped with the pressure control valve 10 having such a configuration, the pressure control valve 10 is in the state shown in FIG. 1 when the brake pedal 27 is not depressed. That is, the solenoid 16 constituting the control force applying means 10b is in a de-energized state, and the actuating piston 15
is located at the retreating end. In this state, the annular groove 12a of the spool 12 communicates with the control pressure port 11d, communicates with the first low pressure port 11f, and is cut off from communication with the high pressure port 11e. Therefore, the control pressure port 11d communicates with the reservoir 26, and the wheel cylinder 23 has the same atmospheric pressure as the brake fluid pressure in the reservoir 26.

[0020] When the depression operation of the brake pedal 27 is started, an excitation current corresponding to the depression force on the brake pedal 27 is applied to the solenoid 16, and the actuating piston 15 slides toward the - end side in accordance with the excitation current. . As a result, the spool 12 slides against the compression spring 14 and blocks communication between the annular groove 12a and the first low pressure port 11f, and when the spool 12 slides further, the annular groove 12a connects to the high pressure port 11f.
This leads to communication with 1e. During this time, the annular groove 12a always maintains communication with the control pressure port 11d. As a result, the control pressure port 11d communicates with the high pressure port 11e, and high control hydraulic pressure is applied to the wheel cylinder 23.

The communication between the control pressure port 11d and the high pressure port 11e also increases the internal pressure in the housing hole 11h, and this internal pressure urges the reaction piston 13 together with the compression spring 14 to press the spool 12 toward the operating piston 15. . Therefore, when the pressing force of the actuating piston 15 is larger than the pressing force of the reaction piston 13, the spool 12 slides toward the - end, but when it is smaller, it slides toward the other end for control. When the pressure port 11d is disconnected from the high pressure port 11e and further slid in the same direction, the control pressure port 11
d is communicated with the first low pressure port 11f. Therefore, the spool 12 finally stops when the pressing forces of the actuating piston 15 and the reaction piston 13 are balanced, and the hydraulic pressure of the control pressure port 11d is controlled according to the excitation current, and the control hydraulic pressure is is applied to the wheel cylinder 23.

By the way, in the pressure control valve 10, when the spool 12 slides in the axial direction, the brake fluid in the fluid chamber R of the inner hole 11a is discharged to the reservoir 26 side. is mainly the first communication pipe 28a
When the spool 12 slides a predetermined amount, the second low pressure port 11g is closed as shown in FIG. Therefore, the brake fluid in the fluid chamber R thereafter is transferred to the second communication pipe 2.
8b into the reservoir 26, and an anti-sliding force acts on the spool 12. As a result, the sliding movement of the spool 12 is smooth until just before the control pressure port 11d and the high pressure port 11e communicate with each other, and after that, the spool 12
Excessive sliding is prevented. Therefore, the pressure control valve 1
At 0, the responsiveness during operation is good, and there is no vibration caused by excessive sliding in the spool 12, making it possible to accurately control the hydraulic pressure on the control pressure port 11d side to the set value. can.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a pressure control valve according to an embodiment of the present invention.

FIG. 2 is a partial side view showing a state in which the spool employed in the pressure control valve is in the middle of sliding.

FIG. 3 is a system diagram of a brake system using the same pressure control valve.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 10...Pressure control valve, 10a...Pushing force generation means, 10b...
Control force applying means, 11...housing, 11a...inner hole, 1
1d...Control pressure port, 11e...High pressure port, 11f, 1
1g, 11h...Low pressure port, 12...Spool, 12a...
Annular groove, 13... Reaction piston, 15... Actuation piston, 1
6... Solenoid, 21... Master cylinder, 22... Change valve, 23... Wheel cylinder, 24... Accumulator, 27... Brake pedal, 28a... First communication pipe,
28b...Second communication pipe line, 28c...Orifice, R...Fluid chamber.

Claims (1)

[Claims] 1. A housing having an axially extending inner hole, a high pressure port, a low pressure port, and a control pressure port located at a predetermined interval in the axial direction and communicating with the inner hole; a spool that is fluid-tightly and slidably inserted into the hole and selectively communicates the control pressure port with the low pressure port and the high pressure port by sliding in the axial direction; and an end side of the spool. a pressing force generating means that faces into a fluid chamber formed in the spool and presses the spool in a direction to cut off communication between the control pressure port and the high pressure port by the action of fluid pressure of the control pressure port; and the other end of the spool. A spool-type pressure control valve comprising a control force applying means located on the side that generates a driving force proportional to the excitation current to the solenoid and applies a control force to the spool that counters the pressing force, The fluid chamber communicates with a fluid reservoir through a first communicating conduit and a second communicating conduit provided with an orifice, and of these two communicating conduits, the first communicating conduit communicates with the second communicating conduit. A spool-type pressure control valve, wherein the spool-type pressure control valve is opened to the fluid chamber by being displaced toward the -end side of the spool compared to the conduit.