JP2005030515A - Normally-open-type solenoid valve - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a normally-open-type solenoid valve for controlling relief pressure by a current, which can change the relief pressure in compliance with demand and can be set at a stable high relief pressure. <P>SOLUTION: The normally-open-type solenoid valve 10 includes a current control means which controls the value of the current supplied to a coil 12, and a relief means contained in a movable core 40. The current control means can supply the current within a first current value range and the current within a second current value range to the coil 12. By supplying the current within the first current value range to the coil 12, it is possible to set a first relief pressure specified by the elastic force of an elastic urging member 44, and by supplying the current within the second current value range to the coil 12, it is possible to set a second relief pressure lower than the first relief pressure and variably determined by the attraction force. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a normally open solenoid valve having a valve body that opens and closes a hydraulic fluid flow path.

  Conventionally, electromagnetic valves (solenoid valves) that open and close the working fluid flow path are normally open solenoid valves (normally open valves) that are normally opened and closed by excitation of a fixed core by energization of a coil. is there. Such a normally open type electromagnetic valve includes a valve seat that forms an opening of a hydraulic fluid flow path, and a valve body that can move in contact with and away from the valve seat. The valve body is provided at the tip of a retainer that moves forward and backward in the fixed core. Shield the road. When energization of the coil is stopped, the hydraulic fluid passage can be communicated by separating the valve body from the valve seat.

  As such a normally open type electromagnetic valve, there is one provided with a relief means provided inside a movable core (for example, see Patent Document 1). The relief means of this normally open type electromagnetic valve includes a push rod that can push the retainer to the valve seat side in the guide hole formed in the center of the movable core, and an elastic bias that biases the push rod to the valve body side. The relief spring which is a member is accommodated. Even when the movable core moves forward due to the excitation of the coil and the push rod pushes the retainer to close the valve, if the fluid pressure received by the valve body exceeds the spring force of the relief spring, the relief spring is compressed and the valve body Opens and can relieve excess fluid pressure.

However, in such a normally open type electromagnetic valve, the set relief pressure must be dependent on the spring force of the relief spring, and it is not easy to change the relief pressure as desired.
JP 2002-18416 A

  The present invention provides a normally open solenoid valve for controlling the relief pressure as a current, wherein the relief pressure can be changed as desired and a stable high relief pressure can be set. For the purpose.

In order to solve the above problems, in the normally open solenoid valve according to the first aspect of the present invention,
A fixed core;
A valve member that is disposed so as to be seated with respect to the valve seat, and that opens and closes the flow path of the hydraulic fluid;
A seat spring for urging the valve member in the separating direction;
A movable core disposed opposite to the fixed core and capable of moving forward and backward with the valve member with respect to the valve seat;
A coil that energizes the fixed core by energization to advance the movable core in the seating direction of the valve member;
Current control means for controlling a current value to be supplied to the coil;
A relief means built in the movable core, and when the movable core advances in the seating direction of the valve member, the relief means pushes the valve member in the valve closing direction by the elastic force of the elastic biasing member,
The current control means includes
A current in a first current value range that compresses the elastic biasing member to cause the stationary core to adsorb the movable core and generate a suction force to seat the valve member on the valve seat;
A current in a second current value range that does not compress the elastic urging member and generates a suction force to seat the valve member on the valve seat while the fixed core and the movable core are separated from each other; Is selectively controlled to energize the coil,
By energizing the coil with a current in the first current value range, the first relief pressure specified by the elastic force of the elastic biasing member,
By energizing the coil with a current in the second current value range, a second relief pressure that is variably set by the suction force and lower than the first relief pressure can be selectively set.

  According to the first aspect of the present invention, since the first relief pressure is specified by the elastic force of the elastic biasing member, a stable relief pressure can be set with respect to the pressure received from the hydraulic fluid of the valve member. Accordingly, a high relief pressure with little variation can be set by adopting a relatively simple configuration of an elastic biasing member. In the second current value range, the second relief pressure lower than the first relief pressure is variably set according to the current value regardless of the elastic force of the elastic urging member, and the relief pressure is set according to the request. can do.

  Furthermore, according to the normally open solenoid valve according to the first aspect of the present invention, the amount of change in the attractive force due to the amount of change in current in the second current value range is reduced, and the second relief due to the variation in current value. It is also possible to reduce the fluctuations in pressure (that is, low relief pressure). In this case, in the first current value range, a higher suction force is generated than in the state where the fixed core and the movable core are attracted and separated from each other, so that it is necessary to set the first relief pressure. The first current value range is not so high, and power saving is achieved.

Here, the normally open solenoid valve according to the first aspect of the present invention is:
The current control means can variably control the value of the current in the second current value range energized to the coil so that the second relief pressure can be variably set to an arbitrary pressure value.

  By setting it as such a structure, the 2nd relief pressure can be variably set to arbitrary pressure values, and the freedom degree of the arbitrary pressure setting according to the request | requirement of a use condition becomes high.

  The relief means of the normally open solenoid valve according to the first aspect of the present invention includes a contact member that is slidably guided in a guide hole penetrating in the axial direction of the movable core and fixed to the guide hole. And a relief spring that is an elastic biasing member disposed between the contact member and the receiving member. The abutting member of the relief means abuts on the end of the valve member, and the movable core advances toward the fixed core to push the valve member.

  With this configuration, when the current value selected and controlled from the second current value range is applied to the coil and the movable core is attracted to the fixed core, the seat spring is compressed earlier than the relief spring, and the valve The body sits on the valve seat. Further, when a current value selected and controlled from the first current value range is energized to the coil, the relief spring is compressed after the valve body is seated on the valve seat body, and the movable core is attracted to the fixed core.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a longitudinal sectional view showing a normally opened electromagnetic valve according to an embodiment of the present invention in an open state. FIG. 2 is a longitudinal sectional view showing a closed state of the normally open electromagnetic valve according to the embodiment of the present invention. FIG. 3 is a longitudinal sectional view showing a closed valve state in which the movable core and the fixed core of the normally open solenoid valve according to the embodiment of the present invention are in contact with each other. FIG. 4 is a partially enlarged view of FIG. FIG. 5 is a current-relief pressure characteristic diagram of the normally open solenoid valve according to the embodiment of the present invention.

  An electromagnetic valve according to an embodiment of the present invention is a normally-open electromagnetic valve 10 as shown in FIG. 1 for opening and closing a hydraulic fluid passage of a vehicle brake hydraulic pressure control device, for example. A part of the normally open solenoid valve 10 is inserted into a mounting hole 3 formed in a base 1 made of aluminum, for example, and is fixed by an annular locking member 4. The normally-open electromagnetic valve 10 is accommodated in a fixed core 20 fixed to the base body 1, a valve seat body 60 that forms an opening for a flow path of hydraulic fluid, and a valve hole 22 that penetrates the fixed core 20 in the longitudinal direction. The retainer 30 and the valve body 50 as valve members to be operated, the seat spring 52 that urges the valve body 50 in the seating direction, and the fixed core 20 are disposed so as to be opposed to the valve seat body 60. And a movable core 40 that moves forward while pushing 50. Further, the normally open type electromagnetic valve 10 controls the coil 12 that energizes the fixed core 20 by energization and advances the movable core 40 in the seating direction of the valve body 50, and the current value that is energized to the coil 12 (not shown). Current control means, and a relief means 43 that is built in the movable core 40 and pushes the retainer 30 in the seating direction.

  The fixed core 20 is a substantially cylindrical member formed of a magnetic material such as iron or an iron alloy. The fixed core 20 has a first opening 24 and a second opening 26 that open to the hydraulic fluid channel 2 formed in the base 1. On the first opening 24 side of the fixed core 20, an annular seal member C <b> 2 made of a rubber composition is disposed between the base 1 and the working fluid flow path on the first opening 24 side and the second opening 26 side. 2 is liquid-tightly sealed. An annular seal member C1 made of a rubber composition is disposed between the fixed core 20 and the base 1 at the second opening 26 side. The outside is liquid-tightly sealed. A first filter member F <b> 1 is attached to the first opening 24 of the fixed core 20. A cylindrical valve seat body 60 is fitted and fixed to the first opening 24 side which is one open end of the valve hole 22 of the fixed core 20.

  The opening side of the bottomed cylindrical guide tube 18 is welded and fixed to the fixed core 20 protruding from the upper surface of the base 1, and the coil 12 wound around the resin bobbin 14 and the outside of the coil 12 are connected. A covering coil case 16 is attached. The guide cylinder 18 has a thin cylindrical portion having an inner diameter substantially the same as the outer peripheral surface of the fixed core 20 and a hemispherical bottom portion that closes an end portion of the cylindrical portion. The opening-side inner peripheral surface of the upper portion of the guide tube 18 is welded and fixed to the outer peripheral surface of the fixed core 20. A movable core 40 is built in the guide cylinder 18, and the movable core 40 is slidably guided on the inner peripheral surface of the cylindrical portion, and is retracted by contacting the inner surface of the bottom portion.

  The coil 12 is electrically connected to current control means (not shown) through a terminal 13. The current control unit selectively controls the energization of an arbitrary current value to the coil 12 according to the use state of the brake fluid pressure control device.

  The movable core 40 has a substantially cylindrical shape made of a magnetic material such as an iron-based metal, and a plurality of, for example, three communication grooves 41 extending along the longitudinal axis direction are formed on the outer peripheral surface in the circumferential direction. The hydraulic fluid can be circulated by communicating with 22. The movable core 40 is spaced apart from the fixed core 20 in a non-energized state of the coil 12, and is moved forward by being attracted to the fixed core 20 side in the energized state of the coil 12. A guide hole 42 penetrating in the axial direction is formed at the center of the movable core 40, and a relief means 43 is provided in the guide hole 42.

  The relief means 43 includes a contact member 48 that is slidably guided in the guide hole 42 and can be advanced and retracted, and a bottomed cylindrical receiving member that is press-fitted and fixed to the rear end portion (the upper end portion in FIG. 1) of the guide hole 42. 47 and a relief spring 44 that is an elastic biasing member disposed between the contact member 48 and the receiving member 47. The abutting member 48 of the relief means 43 abuts against the end of the retainer 30, the coil 12 is excited, and the movable core 40 is attracted toward the fixed core 20 and moves forward to push the retainer 30. The relief spring 44 is set to have a stronger spring force than the seat spring 52 that urges the valve body 50 from the valve seat body 60 in the separating direction. Therefore, when the coil 12 is energized and the movable core 40 is attracted to the fixed core 20, the seat spring 52 is compressed earlier than the relief spring 44 and the valve body 50 is seated on the valve seat body 60.

  As shown in FIG. 4, the contact member 48 has a thin bottomed cylindrical shape, and includes a small diameter portion 481, a large diameter portion 482, a bottom portion 483 formed at the end of the small diameter portion 481, and a small diameter portion 481. And a step portion 484 connected to the large diameter portion 482. One end of the relief spring 44 comes into contact with the inner side surface of the stepped portion 484, and the outer side surface of the stepped portion 484 comes into contact with a stopper stepped portion 462 formed to protrude inside the guide hole 42 of the movable core 40. The advance limit of the member 48 is defined. The bottom 483 is formed on a flat surface and abuts against the end surface 36 of the retainer 30. Between the small diameter portion 481 of the contact member 48 and the small diameter portion 481 side of the large diameter portion 482 and the guide hole 42, a communication path is formed so that hydraulic fluid can flow. The hydraulic fluid can communicate with the relief means by the formed communication hole 49.

  The retainer 30 has a substantially cylindrical shape, and is slidably guided by a valve hole 22 penetrating in the axial direction of the fixed core 20 so as to freely advance and retract. A substantially conical valve body 50 is press-fitted and fixed at the tip of the retainer 30, and an end surface 36 with which the contact member 48 of the movable core 40 contacts is formed at the other end. A plurality of flow grooves 32 are formed on the outer peripheral wall surface of the retainer 30 to allow the working fluid to flow. The valve body 50 is an abutting portion of a seat spring 52 as a biasing member with a flange portion protruding in an annular shape.

  The valve seat body 60 is substantially cylindrical and has an internal flow passage penetrating in the axial direction. The valve seat body 60 includes a first valve seat body opening portion 62 having a small diameter and a second valve seat body opening portion 64 having a large diameter. Have. The valve seat body 60 is fitted and fixed to the first opening 24 side of the valve hole 22 of the fixed core 20, and the second valve seat body opening 64 opens into the first opening 24 of the fixed core 20. In the first valve seat opening 62 of the valve seat 60, a valve seat 66 is formed on which a seal portion formed at the tip of the valve body 50 is seated. The valve seat 66 is formed with a tapered surface that increases in diameter toward the outside of the valve seat body 60, and a first cross section of the first valve seat body is brought into contact with an arc-shaped seal portion formed at the tip of the valve body 50. The opening 62 is closed and closed.

  Hereinafter, the operation of the normally open solenoid valve 10 according to the present embodiment will be described. The normally open solenoid valve 10 is controlled by a demagnetized state in which the valve body 50 is normally opened, a state controlled by a current value in the first current value range, and a current value in the second current value range. And having a state.

(Operation in the demagnetized state)
FIG. 1 shows a demagnetized state of the normally open solenoid valve 10. In a so-called demagnetization state in which no current is supplied from the current control means to the coil 12, the retainer 30 and the valve body 50, which are valve members, are arranged away from the valve seat 66 by a seat spring 52. Accordingly, the valve body 50 is always open in this demagnetized state, and the hydraulic fluid flows from the first opening 24 through the first valve seat opening 62 to the second opening 26. At this time, the retainer 30 is biased toward the movable core 40 by the spring force of the seat spring 52. Although the contact member 48 of the relief means is in contact with the end surface 36 of the retainer 30, the spring force of the seat spring 52 is smaller than the spring force of the relief spring 44, so the relief spring 44 is not compressed. Therefore, the retainer 30 pushes up the movable core 40 while the step 484 of the contact member 48 is in contact with the stopper step 462 of the guide hole 42, and the end of the movable core 40 is placed on the inner surface of the bottom of the guide tube 18. It is held at the pushed back limit.

(Operation in the second current value range)
Next, the operation state of FIG. 2 in which the coil 12 is energized with a current value selected from the second current value range will be described with reference to the current-relief pressure characteristic graph of FIG. FIG. 5 shows the characteristic lines S1 and S2 of the normally open solenoid valve 10 with the horizontal axis representing the current value for energizing the coil 12 and the vertical axis representing the set relief pressure. The current control means (not shown) selectively controls the current value in the second current value range, whereby the relief pressure of the normally open solenoid valve 10 can be set to the second relief pressure.

  In the present embodiment, the current value in the second current value range is a range indicated by a current value A to a current value E lower than the current value F in FIG. S1 is shown. When the current value is controlled to be energized within a second current value range by a current control means (not shown), the second relief pressure is set to a range indicated by the relief pressure P2 to the relief pressure P5 in FIG.

  As shown in FIG. 2, the normally open solenoid valve 10 set at the second relief pressure advances the movable core 40 toward the fixed core 20 without compressing the relief spring 44. For example, when a current value B selected from the second current value range is energized and controlled to the coil 12 from a current control unit (not shown), the movable core 40 is attracted to the fixed core 20 side by the magnetic attraction force. This attractive force is a force that attracts each other by the magnetic flux between the end face 28 of the fixed core 20 on the movable core 40 side and the facing portion 46 of the movable core 40 that faces the end face 28. The second relief pressure of the normally open solenoid valve 10 in which the current value B is energized is the relief pressure P4. When the movable core 40 is sucked, the contact member 48 that is in contact with the end surface 36 of the retainer 30 pushes the retainer 30. The suction force generated between the fixed core 20 and the movable core 40 exceeds the spring force of the seat spring 52, and the valve body 50 is seated on the valve seat 66 to close the flow path of the first opening 26. . Since the suction force at this time does not compress the relief spring 44, the fixed core 20 and the movable core 40 are maintained in a separated state as shown in FIG.

  At this time, when the hydraulic pressure of the hydraulic fluid received by the closed valve body 50 becomes P4 or more, the valve body 50 and the retainer 30 push the movable core 40 together with the relief means 43 to open the valve, thereby releasing the hydraulic fluid. To do. The relief means 43 moves back together with the movable core 40 while the step 484 of the contact member 48 is in contact with the stopper step 462 of the guide hole 42 without compressing the relief spring 44.

  Such a relief operation at low pressure is used for automatic follow-up traveling control or the like in a brake fluid pressure control device for a vehicle. When the suction force of the fixed core 20 and the movable core 40 is used for the relief operation, the current value supplied from the current control means to the coil 12 is selectively controlled within the second current value range (for example, changed from B to D). By doing so, various relief pressures (for example, from P4 to P3) can be set.

  If the current-relief pressure characteristic is set to be steep as shown by the characteristic line R1 shown in FIG. 5, for example, in a state where the current value is likely to fluctuate, the variation of the set relief pressure becomes large. Therefore, in the present embodiment, the number of turns of the coil 12 is adjusted so as to have a gentle gradient like the characteristic line S1, thereby suppressing variations in relief pressure due to undesirable fluctuations in the current value. If the gradient of the characteristic line can be made gentle, it can be adopted as appropriate even when the number of turns of the coil 12 is not adjusted.

(Operation in the first current value range)
When the current value supplied to the coil 12 from a current control means (not shown) is further increased and controlled to a current value selected from the first current value range, the relief pressure of the normally open solenoid valve 10 is changed to the first relief pressure. Can be set.

  The current value in the first current value range in the present embodiment is set as a range indicated by the current value F or higher in FIG. In addition, even if the current-relief pressure characteristic of FIG. 5 is set to a gentle slope as shown by the characteristic line S1, the current value in the first current value range is set as a range less than the current value G, thereby reducing the current consumption. Can be small. The normally open solenoid valve 10 controlled to a current value in the first current value range shows the characteristic line S2, and the first relief pressure is set to the relief pressure P1 in FIG. The normally open solenoid valve 10 is in the state shown in FIG.

  When a current selected from a first current value range, for example, a current value F, is controlled from the current control means (not shown) to the coil 12, the fixed core 20 controls the movable core 20 with a current in the second current value range. Generates a stronger suction force than when The abutting member 48 of the relief means 43 pushes the retainer 30 together with the movable core 20, compresses the seat spring 52 against the spring force of the seat spring 52, and seats the valve member 50 on the valve seat 66. Further, the movable core 20 is attracted to the fixed core 40 by compressing the relief spring 44.

  In the state of FIG. 3, the attractive force in a state where the fixed core 20 and the movable core 40 are in contact with each other is stronger than the attractive force in the separated state with the same current value. Further, the adsorption force of the fixed core 20 and the movable core 40 at this time is stronger than the spring force of the compressed relief spring 44. Therefore, for example, if the current supplied to the coil 12 is at least F or more, the movable core 40 does not move backward even if the hydraulic fluid received by the valve body 50 is at the relief pressure P1.

  Therefore, when the hydraulic pressure of the hydraulic fluid received by the valve body 50 increases and becomes the relief pressure P1 or more, the retainer 30 pushes the contact member 48 to compress the relief spring 44 and opens the valve body 50. To relieve the hydraulic fluid. The relief pressure P1 is a first relief pressure specified by the elastic force of the relief spring 44.

  That is, in the first current value range, the relief pressure characteristic line S1 in FIG. 5 becomes the characteristic line S2. That is, in the state of FIG. 2, the magnetic loss is reduced because the fixed core 20 and the movable core 40 are spaced apart, and the magnetic loss is eliminated by the contact between the end face 28 and the facing portion 46 as shown in FIG. This is because of a sudden increase.

  Such relief operation at high pressure is used for traction control in a brake fluid pressure control device for a vehicle. Since the high first relief pressure depends on the spring force of the relief spring 44, as shown in FIG. 5, the relief pressure P <b> 1 is constant within a first current value range equal to or greater than the current value F. If the movable core 40 and the fixed core 20 come into contact with each other and a high suction force can be obtained, the movable core 40 is opened by the relief means without retreating if at least the current value F or less. Therefore, in the present embodiment, in the second current value range, the current-relief that controls the low-pressure relief pressure by controlling the current value and reduces the variation in the low-pressure relief pressure due to the fluctuation of the current value. Although it is a pressure characteristic, a high relief pressure can be achieved with a low power consumption and a simple configuration in the first current value range.

  Since the relief spring 44 is compressed between the current value E and the current value F and the fixed core 20 and the movable core 40 are not in contact with each other, the relief pressure fluctuates due to changes in the spring force. It is not used for relief pressure control by value control.

  In addition, this invention is not limited to this Embodiment, It can deform | transform into various forms within the range of the summary of this invention.

  For example, the relief spring 44 is a spring member, but may be constituted by another elastic member.

It is a longitudinal cross-sectional view which shows the valve opening state of the normally open type solenoid valve which concerns on one embodiment of this invention. It is a longitudinal cross-sectional view which shows the valve closing state of the normally open solenoid valve which concerns on one embodiment of this invention. It is a longitudinal cross-sectional view which shows the valve closing state which the movable core and fixed core of the normally open solenoid valve which concern on one embodiment of this invention contact | abutted. It is the elements on larger scale in FIG. It is an electric current-relief pressure characteristic figure of the normally open type solenoid valve concerning one embodiment of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Substrate 10 Normally open type solenoid valve 12 Coil 20 Fixed core 28 Fixed core end surface 30 Retainer 36 Retainer end surface 40 Movable core 42 Guide hole 44 Relief spring 46 Opposing part 48 Contact member 50 Valve body 52 Seat spring 60 Valve seat body 66 Valve seat

Claims (2)

A fixed core;
A valve member that is disposed so as to be seated with respect to the valve seat, and that opens and closes the flow path of the hydraulic fluid;
A seat spring for urging the valve member in the separating direction;
A movable core disposed opposite to the fixed core and capable of moving forward and backward with the valve member with respect to the valve seat;
A coil that energizes the fixed core by energization to advance the movable core in the seating direction of the valve member;
Current control means for controlling a current value to be supplied to the coil;
A relief means incorporated in the movable core, and when the movable core advances in the seating direction of the valve member, the relief means pushes the valve member in the valve closing direction by the elastic force of an elastic biasing member;
The current control means includes
A current in a first current value range that compresses the elastic biasing member to cause the stationary core to adsorb the movable core and generate a suction force to seat the valve member on the valve seat;
A current in a second current value range that does not compress the elastic urging member and generates a suction force for seating the valve member on the valve seat while the fixed core and the movable core are separated from each other; Is selectively controlled to energize the coil,
By energizing the coil with a current in the first current value range, the first relief pressure specified by the elastic force of the elastic biasing member,
By energizing the coil with a current in the second current value range, it is variably set by the suction force and can be selectively set to a second relief pressure lower than the first relief pressure. Type solenoid valve. The normally open solenoid valve according to claim 1,
The current control means is a normally open solenoid valve capable of variably controlling a current value in the second current value range energized to the coil and variably setting the second relief pressure to an arbitrary pressure value.

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