JP2007146914A - Structure of solenoid valve and method of manufacturing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a solenoid valve which can prevent repeated movement of a valve element caused by a change in pressure-receiving diameter at the beginning of a valve opening stroke of the valve element so as to decrease oscillation phenomena. <P>SOLUTION: The solenoid valve comprises the spherical valve element 38 provided at the top end of a plunger which slides due to magnetic force generated in an electromagnetic coil, a valve seat body 39 arranged coaxially with the plunger and having a passage hole 40 formed therein and axially extending therethrough, and a spherical-surface valve seat 41 which is formed in an opening portion 40a at the top end of the passage hole and from or on which the valve element is separated or seated. The solenoid valve is structured such that the valve element is separated from or seated on the valve seat corresponding to the sliding movement of the plunger so as to open or close the opening at the top end of the passage hole. A rate of decrease of the pressure-receiving diameter D in the valve opening stroke of the valve element is reduced by setting the curvature radius of the valve seat larger than that of the valve element, thereby decreasing the oscillation phenomena of the valve element caused by fluid pressure. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an electromagnetic valve structure used in, for example, an antilock brake device (ABS) for controlling a brake hydraulic pressure of a vehicle, and a method of manufacturing the electromagnetic valve.

  As this type of conventional solenoid valve structure, those described in the following patent documents applied to an antilock brake device are known.

  Briefly speaking, this solenoid valve is a so-called normally closed type pressure-reducing solenoid valve, a valve holding hole formed in the housing, a part formed in the housing, and one end of each wheel cylinder. A brake fluid pressure passage for allowing the brake fluid to flow through, the other end of which is connected to the reservoir, and a passage hole that is housed and held in the valve holding hole and communicates with the brake fluid pressure passage in the radial direction of the peripheral wall. A substantially cylindrical valve body, and a spherical shape that is formed inside the valve body and opens and closes one end opening of the passage hole by being attached to and detached from a spherical valve seat formed at one end opening edge of the passage hole. And a plunger that is slidably provided inside a cylinder fixed to the upper end of the valve body and that opens and closes the valve body.

A fixed core is fixed to one end of the cylinder, and an electromagnetic coil is disposed on the outer periphery of the fixed core. When the fixed core is demagnetized without being energized, the valve spring While the body closes the opening edge, when energized, the plunger is sucked into the fixed core, the opening end is opened by the valve body, and the brake fluid of each wheel cylinder is returned to the reservoir to control the brake fluid pressure. It is like that.
Japanese Patent Laid-Open No. 11-222119 (FIG. 3)

  However, as shown in FIG. 6A, the conventional solenoid valve is formed such that the curvature radius R ′ of the spherical valve seat 2 is smaller than the curvature radius R of the pressure receiving surface 1a of the spherical valve body 1. Yes. For this reason, when the valve body 1 is stroked in the valve opening direction from the state in which the valve body 1 is seated on the upper peripheral edge 2a of the valve seat 2, from the pressure-receiving diameter D of the valve body 1, that is, from the center P of the valve body 1 There is a pressure receiving diameter D between a cone angle θ formed by a straight line connecting the shortest distance from the inner peripheral edge 2a of the upper end of the valve seat 2 to the upper surface of the opening edge 4 on the outer peripheral side of the valve seat 2, and this pressure receiving diameter is present. D is in the range of 1 and 2 which is sharply reduced from the width 0 of the pressure receiving diameter D at the seating position at the upper inner periphery 2a of the valve seat 2 of the valve body 1, and the rate of change in the decreasing direction is large. A large fluctuation occurs in the fluid pressure flowing from the passage hole 3 toward the opening end 3a.

  That is, the pressure receiving diameter D due to the fluid pressure flowing through the passage hole 3 of the valve body 1 is determined by the opening area of the tip opening 3 a of the passage hole 3. The pressure-receiving diameter D when the seated valve is closed is 0, which is the same as the opening area of the tip opening 3a of the passage hole 3, but the valve body 1 moves in the valve opening direction via the plunger as shown by the arrow in FIG. 6A. In the initial stage of stroke and separation from the valve seat 2, the pressure receiving diameter D temporarily changes to 1 and 2 in a direction that greatly decreases stepwise. Along with this, the valve body 1 temporarily repeats the movement in the valve closing direction.

  In this prior art, since the rate of change (change width) of the pressure receiving diameter D is large, the fluid pressure flowing through the passage hole 3 instantaneously decreases, and the valve body 1 (plunger) is closed. The amount of repeated movement in the direction increases.

  As a result, as shown in FIG. 6B and FIG. 7, the fluid pressure fluctuates rapidly and an oscillation phenomenon with a large amplitude occurs, which causes not only abnormal noise but also difficulty in obtaining accurate fluid pressure. . In particular, in a proportional control type electromagnetic valve in which the opening degree is held and controlled at an intermediate position of the valve body 1, the valve body 1 may not be stably held at the intermediate position.

  The present invention has been devised in view of the above-described conventional technical problems, and suppresses a sudden decrease change in the pressure receiving diameter when the valve body moves in the stroke direction in the valve opening direction, thereby sufficiently suppressing the oscillation phenomenon. An object of the present invention is to provide a solenoid valve structure that can be prevented.

  In the first aspect of the present invention, the plunger is slid by the magnetic force generated when the electromagnetic coil is energized, the valve body provided at the tip of the plunger, and the plunger is disposed coaxially. A valve seat having a passage hole formed therethrough in the direction of the internal axis, and a valve seat formed at a front end opening of the passage hole, on which the valve body is attached and detached, and with the sliding of the plunger An electromagnetic valve structure in which the valve body is separated from the valve seat and opens and closes the open end opening of the passage hole, and the shape of the valve seat is changed in accordance with the valve opening stroke movement of the valve body. It is characterized in that it is formed so that the rate of change in the pressure receiving diameter of the valve body determined by the relative relationship with the tip opening area decreases.

  According to this invention, the rate of change in the pressure-receiving diameter of the valve body is determined by the relative relationship between the shape of the valve seat and the tip opening area of the passage hole as the valve body opens. Since the valve body is formed to be small, the rate of change in the pressure-receiving diameter temporarily at the initial stage of valve opening becomes sufficiently small, and the pressure-receiving diameter changes continuously. For this reason, it is possible to sufficiently suppress the fluctuation (oscillation) of the fluid pressure at the tip opening of the passage hole.

  As a result, when such an electromagnetic valve is applied to, for example, a vehicle brake hydraulic pressure control device, it becomes possible to improve the proportional control for controlling the valve body to be held at an intermediate position and the operation responsiveness at the time of transition. Moreover, it is possible to prevent the generation of abnormal noise due to the relatively large oscillation.

  According to a second aspect of the present invention, there is provided a plunger that slides by a magnetic force generated when an electromagnetic coil is energized, a spherical valve body provided at a tip of the plunger, and coaxial with the plunger. And a valve seat having a passage hole formed therethrough in the inner axial direction, and a spherical valve seat formed at a front end opening of the passage hole, on which the valve body is attached and detached, and sliding the plunger Accordingly, the valve body is separated from the valve seat and opens and closes the opening end opening of the passage hole, and the curvature radius of the valve seat is set larger than the curvature radius of the valve body. It is characterized by that.

  Since the present invention merely sets the curvature radius of the valve seat, the same effects as those of the first aspect of the present invention can be obtained with a simple structure, and an increase in cost can be suppressed.

  The invention described in claim 3 is characterized in that a substantially tapered opening edge is formed on the outer peripheral side of the valve seat.

  According to this invention, in addition to the operational effect of the invention according to claim 1 or 2, the change in the pressure receiving diameter of the valve body can be made more continuous, so the above-mentioned oscillation phenomenon is effectively prevented. It becomes possible to do.

  The invention according to claim 4 is characterized in that the electromagnetic valve is a normally closed type which is in a closed state when demagnetized.

  As described above, when performing hydraulic pressure control such that the stroke amount is held at the intermediate valve opening position, the fluid pressure that pushes the valve element back to the closed state can be reduced by the shape of the valve seat. It becomes easy to control the target hydraulic pressure amount.

  The invention according to claim 5 is characterized in that the working fluid flowing through the electromagnetic valve flows in the valve opening direction.

  According to the present invention, in the case of performing hydraulic pressure control that maintains the stroke amount at the intermediate valve opening position, the fluid pressure that pushes the valve element back to the closed state flows in a direction that pushes up the valve element in the valve opening direction. Therefore, when the shape of the valve body and the valve seat is used for the electromagnetic valve having such a configuration, the hydraulic pressure control characteristic at the intermediate valve opening position can be improved.

  The invention according to claim 6 relates to a method of manufacturing an electromagnetic valve, a plunger that reciprocates in an axial direction, a substantially spherical valve body provided at a tip of the plunger, and a passage hole facing the valve body. A substantially spherical valve seat having a larger radius than the valve body is formed at the opening of the passage hole, and a substantially tapered opening edge is formed on the outer periphery of the valve seat. A first step of forming the opening edge portion in a substantially tapered shape by cutting, and after the first step, the opening edge portion is positioned by a tapered surface, and the valve seat is formed into a spherical shape by a jig. And a second step of setting the radius of curvature larger than the radius of curvature of the valve body.

  For example, a solenoid valve used in a brake fluid pressure control device or the like has a very small valve seat dimensional tolerance, for example, the valve seat has a diameter of about 1 to 2 mm, and the processing of the valve seat has a high surface roughness accuracy and positioning. Accuracy is required.

  According to the present invention, the tapered opening edge is formed in advance by cutting and indented by the jig positioned by the tapered shape to form the valve seat in a spherical shape, so that the surface and positioning accuracy are high. In addition, the valve seat can be processed efficiently.

  Embodiments of a solenoid valve structure and a solenoid valve manufacturing method according to the present invention will be described below in detail with reference to the drawings. In this embodiment, what is applied to a pressure reducing solenoid valve of a brake-by-wire device applied to ABS or the like is shown.

  First, a brake fluid pressure control apparatus to which the pressure reducing electromagnetic valve in this embodiment is applied will be briefly described with reference to FIG.

  In the figure, 11 is a master cylinder that generates hydraulic pressure in accordance with the amount of depression of the brake pedal 12, 13 is a reservoir tank that is integrally attached to the master cylinder 11, and 14 is a hydraulic unit. In response to this operation, the hydraulic unit 14 performs hydraulic control on the wheel cylinders 15 and 16 of the left and right front wheels.

  The hydraulic unit 14 is provided with both hydraulic passages 17a and 17b branched from the master cylinder 11 and communicating with the wheel cylinders 15 and 16, respectively, and upstream of the hydraulic passages 17a and 17b. The brake valves 18a and 18b that shut off both hydraulic passages 17a and 17b and close the circuit at the time of braking communicate with the reservoir tank 13 via the flexible tube 19, and the brake hydraulic pressure is supplied to each wheel cylinder via the check valve 20a20b. When the oil pump 21 supplied to 15 and 16 is provided on the downstream side of each of the checks 20a and 20b and only the wheel cylinders 15 and 16 of specific wheels are increased (opened) or reduced (closed). Holding valves 22a and 22b used in the above, and the normally closed type reduction valve provided on the downstream side of the holding valves 22a and 22b. And use solenoid valves 23 and 24, and a.

  In addition, a relief valve 25 for controlling the discharge pressure of the oil pump 21 is provided, and pressure sensors 26a to 26e are provided at respective pressure generation locations. The oil pump 21 is driven by an electric motor 21a that is rotationally driven by a control signal from an electronic controller (not shown). The pressure reducing electromagnetic valves 23 and 24 communicate with flow passages 27 and 27 having one end connected to the wheel cylinders 15 and 16 and the other end connected to the reservoir tank 13 on the low pressure side.

  In the normal brake mode, the shut-off valves 18a and 18b are closed by a control signal from the electronic controller to close the hydraulic circuit, and the holding valves are set in accordance with the operation amount detection signal of the brake pedal 12. The brake fluid pressure from the oil pump 21 to the wheel cylinders 15 and 16 is controlled by opening and closing the valves 22a and 22b, and when the brake pedal 12 is suddenly operated, the pressure reducing solenoid valves are connected via the flow passages 27 and 27. 23 and 24 are also controlled to perform ABS control by increasing / decreasing pressure control.

  The hydraulic unit of the present embodiment is configured to perform hydraulic pressure control on the front wheel left and right wheel cylinders 15, 16, but the same configuration is adopted in hydraulic pressure control on the rear wheel left and right wheel cylinders. Is also possible.

  Further, when the mode is shifted to the fail safe mode, the shut-off valves 18a and 18b are opened to open the hydraulic circuit, and the brake hydraulic pressure is directly applied from the master cylinder 11 according to the pedaling force output from the brake pedal 12. A brake force is applied to the wheel cylinders 15 and 16.

  Next, a specific configuration of the pressure reducing electromagnetic valves 23 and 24 will be described with reference to FIG. For convenience, one electromagnetic valve 23 will be described. The electromagnetic valve 23 includes a valve holding hole 31 formed in an aluminum alloy housing 30, and a cylindrical valve housed and held in the valve holding hole 31. A body 32, a cylindrical metal cylinder 33 fixed to the upper end portion of the valve body 32 and having an upper end portion exposed from the valve holding hole 31, and an electronic controller (not shown) disposed on the outer peripheral side of the cylinder 33 A cylindrical electromagnetic coil 34 that is excited by a control current output from the cylinder 33, a columnar fixed core 35 that is fixed to the upper end of the cylinder 33, and a movable core 36 that is slidably accommodated inside the cylinder 33. The plunger 37 disposed at the tip of the movable core 36, the valve body 38 formed integrally with the tip of the plunger 37, and the valve body 32 are accommodated in the axial direction. A fixed metal cylindrical valve seat 39, a passage hole 40 penetratingly formed in the inner axial direction of the valve seat 39, and communicating with the upstream and downstream of the flow passage 27, and at the tip of the valve seat 39. A substantially spherical valve seat 41 which is formed on the upper surface of the projection 39a and which opens and closes the distal end opening 40a of the passage hole 40 by the valve body 38 separating and seating.

  In the plunger 37, the valve element 38 is seated on the valve seat 41 by the spring force of the valve spring 42 elastically mounted between the bottom surface of the holding hole 35 a formed in the fixed core 35 and the upper surface of the movable core 36. Thus, the tip opening 40a is biased in the closing direction. Further, the return spring 46 is urged in the valve opening direction by a return spring 46 elastically mounted between the front end side step surface of the plunger 37 and the protrusion 39a outer peripheral side step surface of the valve seat 39. The spring force is set to be sufficiently smaller than the spring force of the valve spring 42, and is set to a spring force that simply presses the plunger 37 toward the movable core 36 side.

  At the lower end of the valve seat 39, a filter member 43 for filtering the brake fluid flowing into the passage hole 40 from the flow passage 27 is provided, and a seal ring 44 is provided on the outer periphery. A valve casing 45 that functions as a yoke is attached to the outer peripheral side of the electromagnetic coil 34.

  As shown in FIGS. 1 and 4, the valve body 38 is formed of a metal material in a spherical shape, and its curvature radius R is set to a predetermined length. On the other hand, the valve seat 41 is formed in an annular shape and has a spherical surface as shown between the black dots in FIG. 4, and its curvature radius R ′ is larger than the curvature radius R of the valve body 38. Is also formed large.

  Further, an annular opening edge 46 rising in a tapered shape from the outer peripheral edge (outer black spot) of the valve seat 41 to the outside is continuously formed on the upper surface of the protruding portion 39a of the valve seat 39. .

  The other pressure reducing solenoid valve 24 has the same configuration as the one pressure reducing solenoid valve 23.

  A method for forming the valve seat 41 will be briefly described with reference to FIGS. 3A to 3C. First, the passage hole 40 is formed by a drill along the internal axis direction of the columnar metal material 50 to be the valve seat 39. Subsequently, a conical notch 51 serving as the valve seat 41 and the opening edge 46 is formed by cutting at the hole edge of the tip opening 40a at the upper end (projection 39a) of the passage hole 40 (FIGS. 3A and 3B). reference).

  Next, since the uneven portion 51a due to the tool mark is formed on the surface of the notch 51, the tool mark is indented by a spherical jig to smooth the surface, and the spherical valve seat 41 is formed. Mold (see FIG. 3C). At this time, the valve seat 41 is formed so that the curvature radius R ′ is larger than the curvature radius R of the tip spherical surface (pressure receiving surface 38 a) of the valve body 38.

  Hereinafter, the operation of this embodiment will be described. During the anti-lock brake control, a control current from the electronic controller is output to the pressure reducing electromagnetic valves 23 and 24, and the valve body 23 is shown in FIG. As shown in FIG. 4, when the opening operation is started from the valve closing position (inner black circle) in contact with the inner peripheral edge 41 a of the upper end of the valve seat 41, the inside of the passage hole 40 from each wheel cylinder 15, 16 through the filter member 43. The brake fluid pressure that flows into the valve body acts on the pressure receiving surface 38a on the distal end side of the valve body 38.

  The pressure receiving diameter D of the pressure receiving surface 38a of the valve body 38 is determined by the relative relationship between the valve opening stroke movement of the valve body 38 and the opening area of the tip opening 40a of the passage hole 40. Then, since the curvature radius R ′ of the valve seat 41 is formed larger than the curvature radius R of the valve body 38, the valve body 38 starts from 0, which is the pressure receiving diameter D when the valve is closed, as shown in FIG. 4A. When the stroke is slightly in the opening direction (upward) to the Q position and the pressure receiving diameter D becomes 1, the pressure receiving diameter D of 1 becomes slightly smaller than 0 and the stroke moves further in the opening direction. At the Q1 position, the pressure receiving diameter D becomes 3, which is larger than 0.

  That is, the curvature radius R of the valve body 38 when the valve body 38 is seated on the valve seat 41, and the valve body 38 slightly strokes upward by a predetermined amount from here, and the center of the spherical diameter of the valve body 38 A section of the distance X between the centers of the radii R and R of the valve body 38 until the tip of the line extending in the direction of radius R from the curvature radius R ′ surface of the valve seat 41 exists, and the valve body The pressure receiving diameter D decreases in a section until the valve body 38 is positioned at the position where the shortest distance Y is from the center of the spherical diameter 38 to the boundary point between the valve seat 41 and the tapered surface 46.

  Therefore, in this range, the fluid pressure from the tip opening 40a with respect to the valve body 38 is slightly reduced, and the valve body 38 is temporarily lowered in the valve closing direction as shown in FIGS. However, since the rate of decrease in the pressure receiving diameter D is extremely small, the oscillation waveform amplitude is sufficiently small.

  Thereafter, when the valve body 38 further moves through the valve opening stroke, the pressure receiving diameter D increases to 2 to 3, so that the oscillation phenomenon disappears completely in this range, and when the valve moves further in the valve opening direction, the pressure receiving diameter D becomes 3 to 3. In this case, the decrease rate of decrease in the pressure receiving diameter D is extremely small, and therefore the oscillation waveform amplitude is sufficiently small. That is, when the pressure receiving diameter D is 3 to 4, the intersection of the radial extension lines of the valve body 38 becomes the tapered opening edge 46, so that the pressure receiving diameter D is substantially the same as when the pressure receiving diameter D is 0. Thus, since the decrease rate of change is sufficiently small, the waveform amplitude of oscillation is sufficiently small.

  Further, when the stroke is moved in the valve opening direction, the pressure receiving diameter D becomes constant without changing between 4 and 5, so that no oscillation phenomenon occurs.

  The change from 0 to 5 of the pressure receiving diameter D accompanying the valve opening stroke movement of the valve body 38 described above is expressed as follows.

  Here, θ: pressure receiving angle, R: radius of valve body, R ′: radius of valve seat (indentation sphere), r: diameter of opening of tip of passage hole, r ′: inner radius of tapered opening edge, α: opening Edge taper angle, X: Plunger (valve) stroke amount, X ′: Stroke amount from seating of valve body to centering of valve body

  As described above, in the present embodiment, the rate of decrease in the pressure receiving diameter D at the initial opening of the valve body 38 can be sufficiently reduced as compared with the prior art. The fluctuation of the fluid pressure, that is, the waveform amplitude of the oscillation of the valve body 38 can be sufficiently suppressed.

  As a result, when applied to a brake-by-wire device or the like as in this embodiment, it is possible to improve the proportional control for holding and controlling the valve body 38 at the intermediate position and the operation response during transition. Moreover, it is possible to prevent the generation of abnormal noise due to the relatively large oscillation.

  The present invention is not limited to the configuration of each of the embodiments described above, and can also be applied to devices, actuators, and the like other than the antilock brake device as an application target of the electromagnetic valve.

It is a longitudinal cross-sectional view which shows embodiment of the solenoid valve concerning this invention. It is a circuit diagram of a brake fluid pressure control device to which a solenoid valve is applied. AC is the schematic which shows the formation process which forms the valve seat of the valve seat provided to the embodiment. A is a schematic diagram showing a change in pressure receiving diameter as the valve element moves from the valve seat according to the present embodiment, and B is a corresponding graph showing an oscillation phenomenon accompanying a change in the pressure receiving diameter. It is a graph which shows an oscillation phenomenon from the relationship between the time and the hydraulic pressure which accompany valve opening stroke movement in this embodiment. The relationship between the pressure receiving diameter and the oscillation phenomenon in the prior art is shown. A is a schematic diagram showing a change in the pressure receiving diameter as the valve body moves from the valve seat to the valve opening stroke, and B is an oscillation phenomenon accompanying the change in the pressure receiving diameter. It is a corresponding | compatible graph shown. It is a graph which shows an oscillation phenomenon from the relationship between the time and the hydraulic pressure which accompany valve opening stroke movement in a prior art.

Explanation of symbols

23 ... Solenoid valve for pressure reduction 34 ... Electromagnetic coil 37 ... Plunger 38 ... Valve body 38a ... Pressure receiving surface 39 ... Valve seat 40 ... Passage hole 40a ... End opening 41 ... Valve seat D ... Pressure receiving diameter R ... Radius of curvature R ' ... curvature radius of valve seat

Claims (6)

A plunger that slides due to the magnetic force generated when the electromagnetic coil is energized;
A valve body provided at the tip of the plunger;
A valve seat disposed coaxially with the plunger and having a passage hole formed in the inner axial direction;
A valve seat that is formed at a distal end opening of the passage hole and from which the valve body is seated;
An electromagnetic valve structure that opens and closes the open end opening of the passage hole by the valve body being separated from the valve seat as the plunger slides,
The shape of the valve seat is formed so that the rate of change in the pressure-receiving diameter of the valve body, which is determined by the relative relationship with the tip opening area of the passage hole as the valve opening stroke of the valve body moves, is reduced. A solenoid valve structure characterized by that. A plunger that slides due to the magnetic force generated when the electromagnetic coil is energized;
A spherical valve body provided at the tip of the plunger;
A valve seat disposed coaxially with the plunger and having a passage hole formed in the inner axial direction;
A spherical valve seat that is formed at a tip opening of the passage hole, and on which the valve body is seated;
An electromagnetic valve structure that opens and closes the open end opening of the passage hole by the valve body being separated from the valve seat as the plunger slides,
An electromagnetic valve structure in which a curvature radius of the valve seat is set larger than a curvature radius of the valve body. The electromagnetic valve structure according to claim 1, wherein a substantially tapered opening edge is formed on an outer peripheral side of the valve seat. The electromagnetic valve structure according to claim 1, wherein the electromagnetic valve is a normally closed type that is in a closed state when demagnetized. The electromagnetic valve structure according to any one of claims 1 to 4, wherein the working fluid flowing through the electromagnetic valve flows in a valve opening direction. A plunger that reciprocates in the axial direction;
A substantially spherical valve body provided at the tip of the plunger;
A passage hole is provided facing the valve body, and a substantially spherical valve seat having a larger radius than the valve body is formed at the opening of the passage hole,
A method of manufacturing a solenoid valve in which a substantially tapered opening edge is formed on the outer periphery of the valve seat,
A first step of forming the opening edge in a substantially tapered shape by cutting;
After the first step, positioning is performed by the tapered surface of the opening edge, the valve seat is indented into a spherical shape by a jig, and the curvature radius is set larger than the curvature radius of the valve body. Process,
A method for manufacturing a solenoid valve, comprising: