JP5234101B2 - solenoid valve - Google Patents

Description

  The present invention relates to an electromagnetic valve that opens and closes by reciprocating a valve element to be seated on a valve seat and separated from the valve seat.

  In this type of solenoid valve, for example, as described in Patent Document 1 below, the poppet valve is energized in a direction to close the valve by a spring and is driven in a direction to open the valve by a solenoid by supplying power. There is something to be done. The electromagnetic valve is used in, for example, a hydraulic control device such as a vehicle hydraulic brake device. In such a case, a self-excited vibration in which the valve element (including the plunger holding the valve element) vibrates may occur when the valve is opened and closed.

JP 11-278233 A

  In order to suppress the self-excited vibration of the valve element or the like, for example, as in the technique described in Patent Document 1, the natural frequency of the valve element and the plunger and the pressure fluctuation in the low-pressure side liquid passage connected to the electromagnetic valve There is a means for adjusting the length of the liquid passage so that the natural frequencies of the liquid are different from each other. However, according to that means, it is possible to make the resonance of the valve element etc. difficult to occur, but it does not give a force against the vibration of the valve element etc., and it is possible to reliably suppress the occurrence of self-excited vibration. There is a problem that it is difficult. Such a problem is an example of a problem that can be an obstacle to improving the practicality of a conventional solenoid valve, and there is room for improvement from various viewpoints. In other words, depending on the application and operating conditions of the solenoid valve, by improving the conventional solenoid valve, or by providing the solenoid valve with a new device, mechanism, structure and means for suppressing new self-excited vibration different from the conventional one. Therefore, it is possible to improve practicality by selecting one or more appropriate self-excited vibration suppression devices. The present invention has been made in view of such circumstances, and an object of the present invention is to obtain a more practical electromagnetic valve.

  In order to solve the above problems, a solenoid valve according to the present invention includes: (a) a housing in which a high-pressure side liquid passage and a low-pressure side liquid passage are connected, and the high-pressure side liquid passage and the low-pressure side liquid passage communicate with each other. (B) a plunger provided in the housing so as to be capable of reciprocating in the axial direction; (c) a valve element held at the tip of the plunger; and (d) facing the valve element of the housing. A valve seat that is formed in a tapered shape that extends toward the valve element, the liquid passage on the high-pressure side being opened so as to be closed by the valve element, and (e) the plunger approaches or approaches the valve seat An elastic body that urges in a direction away from the valve seat, (f) a solenoid that generates a magnetic force that moves the plunger in a direction opposite to the direction in which the elastic body urges, and (g) reciprocating the plunger. Including a restraining force imparting device that imparts restraining force. The applicator device (i) moves a base end portion, which is provided on the housing and is opposite to the tip end portion of the plunger, in a direction orthogonal to the direction in which the plunger reciprocates. An orthogonal direction movement restricting portion for restricting, and (ii) an orthogonal direction movement allowing portion for allowing movement of the distal end portion of the plunger in the orthogonal direction, and the valve element is in a state where the plunger is retracted to the maximum. Includes a valve-valve-valve-seat-contact-allowing mechanism that allows the valve to contact the valve seat.

  According to the solenoid valve of the present invention, for example, the vibration of the plunger due to fluctuations in fluid pressure or the like can be suppressed, and a more practical solenoid valve can be obtained. Various aspects of the solenoid valve of the present invention and their functions and effects will be described in detail in the following [Aspect of the Invention] section.

Aspects of the Invention

In the following, some aspects of the invention that can be claimed in the present application (hereinafter sometimes referred to as “claimable invention”) will be exemplified and described. As with the claims, each aspect is divided into sections, each section is numbered, and is described in a form that cites the numbers of other sections as necessary. This is for the purpose of facilitating the understanding of the claimable invention, and is not intended to limit the combinations of the constituent elements constituting the claimable invention to those described in the following sections. In other words, the claimable invention should be construed in consideration of the description accompanying each section, the description of the embodiments, etc., and as long as the interpretation is followed, another aspect is added to the form of each section. In addition, an aspect in which some constituent elements are deleted from the aspect of each item can be an aspect of the claimable invention.

(1) a housing in which a high-pressure side liquid passage and a low-pressure side liquid passage are connected, and the high-pressure side liquid passage and the low-pressure side liquid passage communicate with each other;
A plunger provided in the housing so as to be capable of reciprocating in the axial direction;
A valve element held at the tip of the plunger;
A valve seat that is provided at a position facing the valve element of the housing, and in which the liquid passage on the high-pressure side is opened so as to be closed by the valve element;
An elastic body that biases the plunger toward the valve seat or away from the valve seat;
A solenoid that generates a magnetic force that moves the plunger in a direction opposite to the direction in which the elastic body is biased;
A suppression force applying device that applies a force for suppressing reciprocation of the plunger.
The solenoid valve described in this section opens and closes the valve by switching between a state in which the valve element is seated on the valve seat and a state in which the valve element is separated from the valve seat by reciprocating the valve element. The poppet valve is driven by a solenoid. That is, the valve is configured including the valve element and the valve seat. The movement of the valve element and the plunger in the direction approaching the valve seat may be expressed as forward movement, and the movement of the valve element or the like away from the valve seat may be expressed as backward movement.
This solenoid valve can be configured as either a normally closed valve or a normally open valve. For example, in a mode in which the electromagnetic valve is normally closed, the plunger is urged by the elastic body so that the plunger approaches the valve seat, and the valve element is seated on the valve seat in a state where no electric power is supplied. When the valve is closed and power is supplied, the magnetic plunger moves the plunger of the ferromagnetic body away from the valve seat, and the valve disc is separated from the valve seat. The valve is opened. On the contrary, in a mode in which the electromagnetic valve is normally opened , the valve element is separated from the valve seat by the urging force of the elastic body and the valve is opened in a state where electric power is not supplied.
In general, when the opening of the electromagnetic valve is intermediate, the urging force of the elastic body (hereinafter referred to as “elastic force”) is applied to the valve element and the plunger (hereinafter sometimes abbreviated as “valve element”). The magnetic force of the solenoid and the pressure of the fluid (the differential pressure between the pressure on the high pressure side and the pressure on the constant pressure side) are acting. Here, if the solenoid valve is a normally closed valve, the biasing force of the elastic body acts in the direction in which the valve element approaches the valve seat, whereas the differential pressure acting force based on the fluid pressure and the magnetic force are It acts in a direction to separate the child from the valve seat. However, the balance of the elastic force, magnetic force, and differential pressure acting force may be in a vibrating state, and the valve element or the like may be vibrated in the axial direction (reciprocating direction) to generate self-excited vibration. If this self-excited vibration is large, or if self-excited vibration grows even if it is small at the beginning, for example, it becomes difficult to control the hydraulic pressure or abnormal noise is generated. Become.
On the other hand, according to the present electromagnetic valve, the force that suppresses the reciprocation of the plunger is applied to the plunger, thereby suppressing the vibration of the valve element or the like from growing. be able to. That is, according to the present invention, a more practical solenoid valve can be obtained.
The force that suppresses the reciprocating movement of the plunger is, for example, intentionally increasing the frictional resistance between the plunger and the housing, or keeping the valve element in contact with the valve seat even when the valve is open, as will be described later. Etc. can be given. The restraining force applying device can restrain at least one of forward and backward movement of the plunger. For example, the self-excited vibration can be suppressed by suppressing only the forward movement of the plunger.
This solenoid valve can be configured as, for example, a linear solenoid valve in which the valve opening pressure or valve opening amount changes in accordance with the increase or decrease of the supply current to the solenoid. A linear solenoid valve is equipped with a restraining force imparting device because the valve is often opened at an intermediate opening for hydraulic pressure control and flow rate control compared to an electromagnetic on-off valve that simply switches between opening and closing of the valve. Therefore, there is a great need to suppress self-excited vibration. However, even in the case of an electromagnetic on-off valve, it is effective to provide a restraining force applying device when self-excited vibration may occur.
(2) The orthogonal force applying device that increases the frictional resistance between the plunger and the housing by applying the force in the orthogonal direction that is a direction orthogonal to the direction in which the reciprocating motion is applied to the plunger. The solenoid valve according to item (1), including:
The electromagnetic valve of this section gives a force for moving the plunger relative to the housing in the orthogonal direction, and increases the frictional resistance between the housing and the plunger, for example, by pressing the plunger against the housing. The frictional resistance is generated in a direction that prevents the relative movement of the housing and the plunger in the reciprocating direction, so that self-excited vibration can be suppressed. As will be described later, the orthogonal force applying device includes, for example, an aspect in which a magnetic force is biased and an elastic force in the orthogonal direction are applied in order to generate an orthogonal force that is an orthogonal force.
(3) The plunger has a ferromagnetic shape and a column shape, the housing has a ferromagnetic shape and extends in the reciprocating direction of the plunger, and the plunger is fitted so that the plunger can reciprocate relatively. Including a cylindrical wall to be joined,
The orthogonal force applying device includes a magnetic force biasing device that causes a bias in a sum of magnetic forces acting between the cylindrical wall and the plunger in an orthogonal plane orthogonal to the reciprocating direction of the plunger. The solenoid valve described in (2).
In a normal solenoid valve, the magnetic force acting between the cylindrical wall of the housing and the plunger is balanced as much as possible in an orthogonal plane. Therefore, almost no force is generated to move the cylindrical wall and the plunger relative to each other in the orthogonal direction, and their frictional resistance is very small. On the other hand, the electromagnetic valve of this term can generate a relatively large force that relatively moves them in the orthogonal direction by biasing the magnetic force between the cylindrical wall and the plunger in the orthogonal direction. As a result, the frictional resistance between the cylindrical wall and the plunger is increased, and self-excited vibration can be suppressed.
In order to bias the magnetic force, for example, as described later, the magnetic resistance between the cylindrical wall and the plunger can be made different from other directions in a specific direction within the orthogonal plane. If the magnetic resistance is reduced in a specific direction, the magnetic flux passing through the portion having the low magnetic resistance increases, and the magnetic force attracting the cylindrical wall and the plunger in the specific direction increases. As a result, the frictional resistance between the cylindrical wall and the plunger increases in the specific direction. Conversely, if the magnetic resistance is increased in a specific direction, the frictional resistance between the cylindrical wall and the plunger increases in the direction opposite to the specific direction.
Here, the change in the frictional resistance between the cylindrical wall and the plunger will be described. The magnetic force between the cylindrical wall and the plunger has a magnitude corresponding to the electric power supplied to the solenoid. Therefore, for example, when the solenoid valve is a normally closed valve, the magnetic force increases when the valve opening degree is large, and as a result, the frictional resistance also increases. That is, in the electromagnetic valve of this section, the frictional resistance between the cylindrical wall and the plunger changes according to the electric power supplied to the solenoid. Therefore, when the solenoid valve is a normally closed valve, the frictional resistance is reduced in a state where the opening degree of the valve is small and the self-excited vibration is difficult to occur, so that the valve element or the like can be moved relatively smoothly. At the same time, since the frictional resistance increases in a state where the opening of the valve is large and self-excited vibration is likely to occur, the self-excited vibration is easily suppressed. That is, this solenoid valve has an advantage that the frictional resistance naturally increases in a state where self-excited vibration is likely to occur, and is particularly preferably configured as a normally closed valve. However, even when configured as a normally open valve, self-excited vibration can be suppressed.
(4) The magnetic force biasing device is provided on at least one of the cylindrical wall and the side surface of the plunger in a specific direction within the orthogonal plane, or increases the magnetic permeability compared to other portions. The electromagnetic valve according to item (3), including a magnetic permeability changing unit to be reduced.
The solenoid valve of this section provides a magnetic resistance between the cylindrical wall and the plunger in a specific direction by providing a portion having a large or small magnetic permeability in at least one of the cylindrical wall and the plunger in a specific direction. This is a mode in which the direction is different. A portion having a high magnetic permeability has a reduced magnetic resistance, and a portion having a low magnetic permeability has an increased magnetic resistance.
The magnetic permeability changing unit, for example, uses at least a part of at least one of the cylindrical wall and the side surface of the plunger (hereinafter abbreviated as “plunger or the like”) in a specific direction in the orthogonal direction. Can be provided. For example, if a part of the plunger or the like is replaced with a nonmagnetic material such as a resin, a copper alloy, or an aluminum alloy in a specific direction, the magnetic permeability decreases and the magnetic resistance increases. As a result, the frictional resistance between the cylindrical wall and the plunger can be increased in the direction opposite to the specific direction. Further, a part of the plunger or the like can be formed as a recess or a cavity. If the recess or the like is filled with air or hydraulic fluid, the permeability of the recess or the like is significantly lower than the permeability of the plunger itself.
Further, for example, a part of the plunger or the like can be replaced with a member having a higher magnetic permeability than the plunger main body (for example, the magnetic permeability is several times to several tens of times). In that case, the magnetic resistance of the member having a high magnetic permeability is small as compared with other parts of the plunger main body, and the frictional resistance between the cylindrical wall and the plunger is large in the specific direction.
In addition, the cylindrical wall or the plunger may include a sleeve covering the cylindrical wall main body and the inner peripheral wall thereof, or a sleeve covering the plunger main body and the side surface thereof, and a part of the sleeve may be a magnetic permeability changing portion. For example, the sleeve itself is formed of a non-magnetic material, and a part of the sleeve is formed of a ferromagnetic material as a magnetic permeability changing portion, thereby reducing the magnetic resistance of the magnetic permeability changing portion and the cylindrical wall and plunger in a specific direction. The frictional resistance can be increased. Conversely, the sleeve itself can be made of a ferromagnetic material, and the permeability changing portion can be made of a non-magnetic material, in which case the frictional resistance between the cylindrical wall and the plunger in the direction opposite to the specific direction. Can be increased. Further, as will be described later, a convex portion can be provided on the plunger body, and a portion covering the convex portion of the sleeve can be formed as a thin portion or a notch portion.
The magnetic permeability (μ) can be obtained by dividing the magnetic flux density (B) by the magnetic field strength (H). In the case of a material such as steel whose permeability changes depending on the strength of the magnetic field, for example, the permeability at the strength of the magnetic field when self-excited vibration occurs can be used as a reference. Since self-excited vibration is likely to occur when the valve has an intermediate opening and a relatively large flow rate, the valve opening is about 70% to 80% (the amount of retraction relative to the maximum retraction of the valve). The magnetic permeability in the strength of the magnetic field generated by the amount of power supply that is a ratio) can be used as a reference. In order to cause a significant bias in the magnetic force, for example, it is desirable that the magnetic permeability of the magnetic permeability changing unit is about twice or more (or half or less) of the magnetic permeability before the change.
(5) One of the cylindrical wall and the plunger includes a nonmagnetic sleeve interposed between the cylindrical wall and a side surface that is a surface facing the cylindrical wall of the plunger,
The magnetic force biasing device is provided in at least one of the cylindrical wall, the side surface of the plunger, and the sleeve in a specific orientation in the orthogonal plane, and increases the magnetic permeability compared to other portions. Alternatively, the electromagnetic valve according to (3) or (4), which includes a magnetic permeability changing unit that decreases the magnetic valve.
The aspect of this section is limited to the aspect of the previous section in which one of the cylindrical wall and the plunger includes a non-magnetic sleeve. Even if the permeability changing portion is provided on any of the cylindrical wall, the plunger, and the sleeve, the same effect as that of the above-described aspect can be obtained.
In the aspect of this section, since the sleeve is made nonmagnetic, for example, by replacing a part of the sleeve with a ferromagnetic material, the magnetic resistance of the part can be decreased and the magnetic flux can be increased.
(6) The electromagnetic valve according to (5), wherein the magnetic permeability changing portion includes a convex portion provided to protrude from the one of the cylindrical wall and the side surface of the plunger.
According to the aspect of this section, it is possible to easily reduce the magnetic resistance between the portion provided with the convex portion and the other of the cylindrical wall and the side surface of the plunger. In addition, a thin part or a notch part can be provided in the part which covers the convex part of a sleeve.
(7) The orthogonal force applying device includes an elastic body that is provided on one of the plunger and the housing and applies an elastic force that urges the plunger and the housing in the orthogonal direction. The solenoid valve according to item.
The electromagnetic valve of this section is a mode in which an orthogonal force is generated by an elastic body in order to increase the frictional resistance between the plunger and the housing. According to the aspect of this section, for example, if a concave portion is provided in one of the plunger and the housing and an elastic body such as rubber is provided in the concave portion, the frictional resistance can be increased, and self-excited vibration can be easily generated. Can be suppressed. Further, an elastic body and an abutting member that is urged in an orthogonal direction by the elastic body and abuts against the other of the plunger and the housing can be provided on one of the plunger and the housing.
The suppression of the self-excited vibration is the same as the above-described “bias the magnetic force” except that the frictional resistance does not change according to the supplied power.
(8) The housing includes a cylindrical wall in which the plunger extends in the reciprocating direction of the plunger and the plunger is fitted so as to be relatively reciprocating.
The orthogonal force applying device is rotatably held by the one of the plunger and the housing, and is pressed against the other of the side surface of the plunger and the cylindrical wall by the elastic force of the elastic body, and the plunger The electromagnetic valve according to item (7), further including a rotating body that rotates in accordance with relative reciprocation between the cylindrical wall and the cylindrical wall.
According to this aspect, the rotating body increases the frictional resistance between the plunger and the cylindrical wall while avoiding the occurrence of local friction between the orthogonal force applying device and the other of the plunger and the cylindrical wall. Can be made.
(9) The valve seat is formed in a tapered shape spreading toward the inside of the housing,
The restraining force applying device is
An orthogonal movement restricting portion that is provided in the housing and restricts the movement in the orthogonal direction of a base end portion that is a portion on the opposite side of the distal end portion of the plunger;
A valve element for allowing the valve element to come into contact with the valve seat even when the plunger is retracted to the maximum extent. The electromagnetic valve according to item (1), including a valve seat contact allowing mechanism.
In the aspect of this section, the self-excited vibration is suppressed by suppressing the movement of the plunger toward the valve seat. When the valve is opened, it has been confirmed that the valve element moves obliquely in a state where the valve element is in contact with the tapered surface of the valve seat even in the conventional electromagnetic valve in a state where the retreat distance of the plunger is not more than a certain degree. And even if the fluid pressure fluctuates in a state where the valve element is in contact with the valve seat, the forward movement of the plunger is suppressed, so that the self-excited vibration is suppressed. However, conventionally, the allowable movement amount in the orthogonal direction of the distal end portion of the plunger is set to be small, and when the opening degree of the valve becomes large and the plunger is retracted to some extent, the valve element cannot move diagonally, It was configured to leave.
On the other hand, in the aspect of this section, the movement of the tip of the plunger in the orthogonal direction is allowed to be larger than before, and the valve element is moved to the valve seat until the valve is fully opened, that is, until the plunger is fully retracted. It can be kept in contact. As a result, self-excited vibration is suppressed regardless of the degree of opening of the valve. In order to allow the movement of the plunger tip in the orthogonal direction, the clearance between the plunger and the housing may be increased. For example, the diameter of at least one valve seat side portion of the plunger and the housing is reduced or increased. In addition, as described later, a tapered portion can be provided on at least one of the plunger and the housing. For example, the plunger can have a columnar shape (columnar shape or the like) extending in a direction in which the plunger reciprocates.
In the aspect of this section, contact between the valve element and the valve seat is allowed, and they are not forced to contact. Therefore, if the valve element is naturally separated from the valve seat when the valve opening is in an intermediate state, the plunger is moved relative to the housing by a device similar to the orthogonal force applying device described above, for example. It is also possible to force the valve element to contact the valve seat by applying a force for moving in the orthogonal direction. In that case, the orthogonal force applying device does not necessarily need to increase the frictional resistance, and may generate a relatively small force.
(10) The valve-valve valve seat contact allowing mechanism is provided in at least one of the plunger and the housing, and gradually increases the clearance between the plunger and the housing in the direction from the base end portion to the tip end portion of the plunger. The solenoid valve according to item (9), including a tapered portion.
According to the solenoid valve of this section, by providing the tapered portion, it is possible to allow the movement of the distal end portion of the plunger in the orthogonal direction while suppressing an increase in the separation distance between the plunger and the housing. Therefore, an increase in magnetic resistance between the plunger and the housing can be suppressed.
(11) The electromagnetic valve is a normally closed valve, and the magnetic path forming member that is one component of the solenoid includes a contact portion that contacts the plunger and defines a retreat limit of the plunger. Or the electromagnetic valve according to any one of (10).
The solenoid valve of this section is a mode in which when the valve is fully opened, the plunger comes into contact with the contact portion and suppresses self-excited vibration. Further, with respect to the aspect depending on the item (9) or the item (10), there is an advantage that the “state in which the plunger is fully retracted” is clearly defined by the contact portion. However, it is not essential. The retracted position of the plunger in a state where the maximum current is supplied to the solenoid can be set as the retracted limit. The state where at least a part of the plunger is in contact with the contact portion can also be included in the “state where the plunger is retracted to the maximum”.

It is a figure which shows notionally the hydraulic brake system of the vehicle provided with the solenoid valve which is one Example of claimable invention. It is front sectional drawing of the said solenoid valve. It is a side view of the plunger of the solenoid valve. It is a figure which shows typically the force which acts on the said plunger. It is a figure which shows typically the magnetic force line which the solenoid of the said solenoid valve generates. It is a figure which shows the flowchart of the hydraulic-pressure control routine which controls the said solenoid valve. It is a figure which shows the flowchart of a pressure increase process routine. It is a figure which shows the flowchart of a pressure reduction process routine. It is front sectional drawing of the solenoid valve of an Example different from the above. In another Example different from the above, it is a figure which shows the movement of a ball | bowl typically. It is a front view which shows typically the force which controls the movement of an orthogonal direction to the plunger of the conventional solenoid valve. It is front sectional drawing of the solenoid valve of the said Example. It is a front view which shows the state which the plunger of the said solenoid valve retracted | retreated.

  Embodiments of the claimable invention will be described below with reference to the drawings. In addition to the following examples, the claimable invention can be practiced in various modifications based on the knowledge of those skilled in the art, including the aspects described in the above [Aspect of the Invention] section. .

  FIG. 1 conceptually shows a hydraulic brake system for a vehicle including an electromagnetic hydraulic control valve according to an embodiment of the claimable invention. The hydraulic brake system includes a brake pedal 10 serving as a brake operation member, a master cylinder device 12, and a brake actuator 14.

  The master cylinder device 12 includes a master cylinder 18 that pressurizes hydraulic fluid (brake fluid) based on depression of the brake pedal 10. In this embodiment, the master cylinder 18 is provided with two pressurizing chambers 20 and 22, and the pressurizing chambers 20 and 22 rotate the left front wheel 28 and the right front wheel 30 through liquid passages 24 and 26, respectively. The brakes are connected to wheel cylinders 32 and 34 for braking. The master cylinder device 12 is provided with a reservoir 36 in which the working fluid is stored at atmospheric pressure, and the working fluid is supplied from the reservoir 36 to each of the pressurizing chambers 20 and 22 of the master cylinder 18. When the brake pedal 10 is depressed, the communication between the reservoir 36 and the pressurizing chambers 20 and 22 is cut off, and the hydraulic fluid pressurized in the pressurizing chambers 20 and 22 is transferred to the wheel cylinders 32 and 34. To be supplied. Further, a stroke simulator 42 is connected to one pressurizing chamber 20 of the master cylinder 18 via an electromagnetic on-off valve 40.

The brake actuator 14 will be described.
The brake actuator 14 controls the hydraulic pressures of the wheel cylinders 50 and 52 of the brake that brake the rotation of the wheel cylinders 32 and 34 and the left rear wheel 46 and the right rear wheel 48, respectively. As shown in FIG. 1, the brake actuator 14 includes two master cut valves 56 and 58, a power hydraulic pressure source 60 as a hydraulic pressure source, a hydraulic control valve device 62, two master cylinder pressure sensors 64, and four wheel cylinders. A pressure sensor 66 is provided. These components of the brake actuator 14 are assembled to a block-shaped main body member (not shown) to constitute one unit.

  The power hydraulic pressure source 60 includes a pump 70 that pumps hydraulic fluid from the reservoir 36, an electric motor 72 that drives the pump 70, an accumulator 74 that stores hydraulic fluid discharged from the pump 70 in a pressurized state, and a pump 70. And a relief valve 76 that regulates the discharge pressure to a set value or less.

  The four wheel cylinders 32, 34, 50, 52 are connected to the power hydraulic pressure source 60 via a hydraulic pressure control valve device 62. The hydraulic pressure control valve device 62 is an electromagnetic pressure control valve for pressure increase (hereinafter referred to as a pressure increase valve) that controls the flow of hydraulic fluid from at least one of the pump 70 and the accumulator 74 to the wheel cylinders 32, 34, 50, 52. 80, 82, 84, 86, and a pressure reducing electromagnetic hydraulic pressure control valve that controls the outflow of hydraulic fluid from each wheel cylinder 32, 34, 50, 52 to the reservoir 36 (hereinafter abbreviated as a pressure reducing valve). 90, 92, 94, 96. The pump 70 and the accumulator 74 and the pressure increasing valves 80 to 86 are connected by a pressure increasing passage 98, and the pressure reducing valves 90 to 96 and the reservoir 36 are connected by a pressure reducing passage 100. ing. Each of the four wheel cylinders 32, 34, 50, 52 is provided with one pressure increasing valve and one pressure reducing valve, and the hydraulic pressure is controlled independently of each other. The wheel cylinder passages 102, 104, 106 and 108 are connected to the wheel cylinders 32, 34, 50 and 52, respectively.

  A hydraulic pressure source hydraulic pressure sensor 110 that detects the hydraulic pressure of the power hydraulic pressure source 60 is provided between the pump 70 and the pressure increasing valves 80 to 86. Each wheel cylinder passage 102 to 108 is provided with a wheel cylinder pressure sensor 66 for detecting each hydraulic pressure of the wheel cylinders 32, 34, 50, 52. The master cut valves 56 and 58 are provided between the two pressurization chambers 20 and 22 of the master cylinder 18 and the wheel cylinders 32 and 34, respectively. The master cut valves 56 and 58 and the pressurization chamber 20 are provided. , 22 are respectively detected by the master cylinder pressure sensors 64 provided between the pressure chambers 20, 22.

  The pressure increasing valves 80 to 86 and the pressure reducing valves 90 to 96 are all linear valves. The linear valve has a predetermined relationship between the hydraulic pressure difference between the upstream side and the downstream side and the supply current, and the valve opening pressure is changed according to the increase or decrease of the supply current. Therefore, the pressure increasing valves 80 to 86 and the pressure reducing valves 90 to 96 can continuously change the wheel cylinder pressure, which is the hydraulic pressure of the wheel cylinder, by controlling the supply current. It can be controlled.

  In the present hydraulic brake system, the pressure increasing valves 80 to 86 are all normally closed valves, and the pressure reducing valves 90 and 92 provided for the left and right front wheels 28 and 30 are normally closed valves, respectively. The pressure reducing valves 94 and 96 provided for are respectively normally open valves. In the present embodiment, the pressure-increasing valves 80 to 86 and the pressure-reducing valves 90 and 92, which are normally closed linear valves, are electromagnetic valves according to the claimable invention. Hereinafter, the pressure increasing valve 80 will be described as a representative.

  As shown in FIG. 2, the pressure increasing valve 80 includes a valve housing 120, a seat valve 122, and a solenoid 124 that is an electromagnetic driving force generator. The seat valve 122 includes a valve seat 128 having a tapered inner peripheral surface, a ball 130 as a valve element, a plunger 132 that holds the ball 130, and an elastic member that urges the plunger 132 in a direction in which the ball 130 approaches the valve seat 128. As a spring 138. In addition, in this embodiment, the solenoid 124 includes a solenoid coil 140, a resin holding member 142 that holds the solenoid coil 140, a first magnetic path forming member 144, and a second magnetic path forming member 146. It is out. The first and second magnetic path forming members 144 and 146 are made of a ferromagnetic material.

  In the present embodiment, the valve housing 120 is formed by integrally assembling a plurality of members. The second magnetic path forming member 146 is concentrically coupled to a second member 152 that is another constituent member of the valve housing 120 by a first member 150 that is one constituent member of the valve housing 120. The first member 150 is made of a nonmagnetic material and has a thin bottomed cylindrical shape, and the second magnetic path forming member 146 is fitted and accommodated in the first member 150. The second member 152 is formed of a ferromagnetic material and has a hollow cylindrical shape. The first member 152 has a non-magnetic material spacer 154 sandwiched between the first magnetic path forming member 146 at one axial end thereof. It is fitted in the member 150. The first magnetic path forming member 144 covers the solenoid coil 140 and is fitted to the outside of the first member 150.

  The second member 152 has a first port 158 formed at two locations on the peripheral wall thereof, and is connected to the wheel cylinder 32 of the left front wheel 28 by the wheel cylinder passage 102. The second member 152 is provided with an assembly member 160 for assembling the pressure increasing valve 80. The assembly member 160 is provided with an opening (not shown) to the hydraulic fluid wheel cylinder 32. Allow inflow. The third member 162, which is still another member constituting the valve housing 120, is fitted to the other end of the second member 152, and a through hole formed through the third member 162 in the axial direction has a power fluid. The second port 164 is configured by being connected to the pressure source 60. The valve seat 128 is provided at the open end of the second port 164 on the first port 158 side.

A plunger chamber 170 is formed between the second and third members 152 and 162 and the second magnetic path forming member 146, and the plunger 132 is fitted so as to be capable of reciprocating in the axial direction. The plunger body 172 has a circular cross-sectional shape, and is fitted into a plunger chamber 170 forming a generally cylindrical space with a slight gap 176 between the inner peripheral wall of the plunger chamber 170. Yes. As a result, in the plunger chamber 170, a valve chamber 178 is formed on the valve seat 128 side of the plunger 132, and a space 180 is formed on the second magnetic path forming member 146 side and on the solenoid 124 side. In this embodiment, the inner peripheral wall of the plunger chamber 170 functions as a “tubular wall”.
The spring 138 is disposed between the plunger 132 and the second magnetic path forming member 146, and the plunger 132 is urged by the spring 138 in the direction in which the ball 130 is seated on the valve seat 128.

The plunger 132 is fixed to a plunger main body 172 made of a ferromagnetic material, a resin-made (non-magnetic) sleeve 174 covering the side surface of the plunger main body 172, and a tip of the plunger main body 172 to fix the ball 130. A ball holder 175 to be held is included.
A fitting hole 182 is provided concentrically with the plunger 132 at the distal end portion of the plunger main body 172, and the fitting shaft portion 184 of the ball holder 175 is press-fitted into the fitting hole 182. The ball holder 175 holds the ball 130 on the axis of the plunger 132 at the holding shaft 186 extending toward the valve seat 128, and the fitting shaft 184 provided at the center of the ball holder 175. When the large diameter portion 188 having a larger diameter comes into contact with the distal end surface of the plunger main body 172, the axial position of the ball 130 in the plunger 132 is defined.

  The plunger body 172 is located on a circumference around the axis thereof, and penetrates the plunger body 172 in the axial direction at a plurality of locations (three locations in the present embodiment) separated in the diameter direction. Extending through-holes 190 (two through-holes are shown in the figure) are formed, and these through-holes 190 and the gap 176 communicate the valve chamber 178 and the space 180 to allow the hydraulic fluid as hydraulic fluid to enter and exit. A communication path 192 is formed. A support member 193 that supports the spring 138 is provided on the end surface of the plunger main body 172 on the spring 138 side.

  The space 180 is a liquid chamber in which hydraulic fluid is stored. The movement limit of the plunger 132 toward the second magnetic path forming member 146 is such that the shoulder surface is in contact with the contact surface or the suction surface 196 (contact portion) provided on the second magnetic path forming member 146. Although specified, a thin plate 194 made of a nonmagnetic material is provided on the shoulder surface. The thin plate 194 secures a distance between the shoulder surface and the suction surface 118, prevents sticking of the plunger 132 attracted to the suction surface 196 by the magnetic attraction force to the suction surface 196, and keeps away from the suction surface 196. It is trying to improve.

  FIG. 3 shows an enlarged view of the plunger 132. On the side surface of the plunger main body 172, a convex portion 200 as a magnetic permeability changing portion formed continuously with the plunger main body 172 is provided. The convex portion 200 is formed of the same material as the plunger main body 172 and has ferromagnetism. Further, the protruding amount of the convex portion 200 from the side surface of the plunger main body 172 is slightly smaller than the thickness dimension of the sleeve 174 so that the convex portion 200 and the inner peripheral wall of the plunger chamber 170 do not contact each other. On the other hand, a notch 202 is formed in a portion of the sleeve 174 facing the protrusion 200, and the protrusion 200 is accommodated in the notch 202. In the figure, the thickness dimension of the sleeve 174 is shown to be thicker than actual.

  In the normally closed pressure reducing valves 90 and 92, the first port 158 is connected to the reservoir 36 via the pressure reducing passage 100, and the second port 164 is connected to the wheel cylinder 50 of each brake of the left and right rear wheels 46 and 48 via the wheel cylinder passages 106 and 108. , 52 except that they are connected to the pressure increasing valve 80.

  Further, the normally open pressure reducing valves 94 and 96 are configured in the same manner as the pressure reducing valve described in Japanese Patent Application Laid-Open No. 2000-95094, for example, and description thereof is omitted.

  This hydraulic brake system is controlled based on a command from an ECU (electronic control unit) 250 shown in FIG. Although not shown, ECU 250 includes a control unit including a computer and an input / output unit, and a plurality of drive circuits. The computer includes a CPU, a ROM, a RAM, and a bus connecting them, and the input / output unit is connected to the input side with various sensors such as the master cylinder pressure sensor 64, and the pressure increasing valves 80 to 86 and the pressure reducing valves. Solenoids such as 90 to 96 are connected to the output side. The ROM stores various programs such as a main routine (not shown), a hydraulic pressure control routine, and a pressure increase processing routine. The vehicle state is acquired based on detection results of various sensors, and electric braking control is performed. Etc. are performed. In the control unit, the main routine is repeatedly executed at predetermined time intervals, and the other subroutines are executed in response to instructions from the main routine.

  In this hydraulic brake system, the ECU 250 sets the target hydraulic pressure for each of the four wheel cylinders 32, 34, 50, 52 when any control is performed by operating the brake actuator 14 such as electric braking control. The current to be supplied to the solenoids 124 of the pressure increasing valves 80 to 86 and the pressure reducing valves 90 to 96 is determined so as to obtain the target hydraulic pressure, and the supply is controlled. By supplying the determined current, the hydraulic pressure control valve device 62 is operated, and the brake is operated while the hydraulic pressures of the wheel cylinders 32, 34, 50, 52 are controlled to the target hydraulic pressure. During these controls, the master cut valves 56 and 58 are closed. When the wheel cylinder pressure is electrically controlled based on the depression of the brake pedal 10, the electromagnetic opening / closing valve 40 is further opened, and the hydraulic fluid is discharged from the pressurizing chamber 20 to the stroke simulator 42. A feeling of operation is given to the driver.

  As described above, the pressure increasing valves 80 to 86 and the pressure reducing valves 90 and 92 are normally closed valves, and are opened by supplying current to the solenoid 124 to control the hydraulic pressure of the wheel cylinder. The pressure reducing valves 94 and 96 are normally open valves, and are closed by supplying a current to the solenoid to control the hydraulic pressure of the wheel cylinder. Hereinafter, the operation of the pressure increasing valve 80 and the hydraulic pressure control of the wheel cylinder 32 will be representatively described.

  The force that acts on the plunger 132 when no current is supplied to the solenoid 124 will be described. As schematically shown in FIG. 4, the urging force Fs of the spring 138 and the differential pressure Fp due to the pressure difference of the hydraulic fluid act on the plunger 132. The differential pressure Fp is a magnitude obtained by multiplying the differential pressure between the pressure of the second port 164 (high pressure side pressure) and the pressure of the wheel cylinder passage 102 (low pressure side pressure) by the sectional area of the seating portion of the ball 130 with respect to the valve seat 128. It becomes. The urging force Fs is set to be larger than the maximum differential pressure Fp that is planned in design, and the plunger 132 is urged in the forward direction by a force obtained by subtracting the differential pressure Fp from the urging force Fs. The ball 130 is pressed against the valve seat 128. The ball 130 is seated on the valve seat 128, and the pressure increasing valve 80 is kept closed.

  When a current is supplied to the solenoid 124, a magnetic field is formed, and as shown schematically by the white arrows in FIG. 5, most of the magnetic field lines are the first magnetic path forming member 144 and the second magnetic field. It passes through the path forming member 146, the plunger 132 and the second member 152. At that time, the lines of magnetic force pass through the gap (space 180) between the plunger 132 and the second magnetic path forming member 146 and the gap (gap 176) between the plunger 132 and the second member 152. In the figure, the direction of the lines of magnetic force is directed from the spring 138 side to the tip end side of the plunger 132, but the direction of the magnetic lines of force can be reversed by changing the direction of the current.

In this solenoid valve 80, the magnetic flux density between the second magnetic path forming member 146 and the rear end surface of the plunger 132 is relatively high, and the direction in which the plunger 132 approaches the second magnetic path forming member 146 is set. A magnetic force Fm is generated that attracts the magnetic field. Further, the urging force Fs and the differential pressure Fp act on the plunger 132, and the relationship of the following equation is established if the conventional solenoid valve is used. Then, the plunger 132 stops at a position where these three forces are balanced.
Fm + Fp = Fs (1-1)

  In the present embodiment, as described above, the convex portion 200 is provided on the side surface of the plunger main body 172. In the present embodiment, the plunger main body 172 and the convex portion 200 are formed of a ferromagnetic material, and the sleeve 174 is formed of a nonmagnetic material. Then, the portion where the convex portion 200 is provided has a higher magnetic permeability than the portion where the convex portion 200 is not provided, and the magnetic resistance between the plunger main body 172 and the second member 152 is reduced. Therefore, compared to the portion covered with the sleeve 174, the magnetic field lines passing through the convex portion 200 are increased (medium size white arrow), the magnetic flux density is increased, and compared with other portions, The force with which the convex part 200 and the inner peripheral wall of the plunger chamber 170 attract each other increases. As a result, the total magnetic force in the orthogonal plane perpendicular to the direction in which the plunger 132 reciprocates is biased, and the force that moves the plunger 132 in the orthogonal direction perpendicular to the direction in which the plunger 132 reciprocates with respect to the inner peripheral wall of the plunger chamber 170. That is, an orthogonal force Fn that is an orthogonal force that moves the plunger 132 to the side where the convex portion 200 is provided with respect to the inner peripheral wall of the plunger chamber 170 is generated. The side surface of the plunger 132 is pressed against the inner peripheral wall of the plunger chamber 170 by the force, and a frictional resistance force Fr (hereinafter abbreviated as a resistance force Fr) is generated when the plunger 132 reciprocates. The resistance force Fr acts in the direction opposite to the direction in which the plunger 132 moves.

When the convex part 200 is not provided, the magnetic forces cancel each other in the orthogonal direction, so the orthogonal force Fn is sufficiently small. Even in that case, the frictional resistance force between the plunger 132 and the plunger chamber 170 is generated, but the frictional resistance force is very small compared with the case where the sum of the magnetic forces is biased, so it should be ignored. To do.
In this embodiment, the “magnetic force biasing device” includes the convex portion 200 and the sleeve 174. Further, the direction in which the convex portion 200 in the orthogonal plane is provided is a “specific direction”.

From the above, when current is supplied to the solenoid 124, four axial forces, magnetic force Fm, differential pressure Fp, biasing force Fs, and resistance force Fr act on the plunger 132. In addition, since the orthogonal force Fn that moves the plunger 132 to the side where the convex portion 200 is provided is a force in a direction orthogonal to the axial direction, the action of the plunger 132 on the reciprocation may not be considered.
The following two relationships hold for the four axial forces. Since the resistance force Fr acts in the direction opposite to the direction in which the plunger 132 moves, the direction in which the opening degree of the seat valve 122 decreases when the opening degree of the seat valve 122 increases (the plunger 132 moves backward). When the opening degree of the seat valve 122 decreases (the plunger 132 moves forward), it acts in the opposite direction.
[When opening degree increases] Fm + Fp = Fs + Fr (1-2)
[When the degree of opening decreases] Fm + Fp = Fs−Fr (1-3)

The magnetic force Fm has a magnitude corresponding to the current i supplied to the solenoid 124, and has a value obtained by multiplying the current i by a coefficient A.
Fm = A · i (1-4)
A small-diameter portion 210 having a diameter smaller than that of the plunger 132 is provided on the end surface of the plunger 132 on the spring 138 side. The second magnetic path forming member 146 that forms the end of the plunger chamber 170 opposite to the valve seat 128 is formed with a recess 212 having a slightly larger inner diameter than the small diameter portion 210. When the plunger 132 moves backward, the small-diameter portion 210 enters the concave portion 212, thereby increasing the lines of magnetic force passing between the side surface of the small-diameter portion 210 and the inner peripheral wall of the concave portion 212. That is, as the plunger 132 moves backward, the distance between the suction surface 196 and the shoulder surface of the plunger 132 decreases, and the action of the magnetic force that moves the plunger 132 backward increases. Since the lines of magnetic force passing through the portion where the side surface and the inner peripheral wall of the recess 212 overlap each other increase, the lines of magnetic force passing between the suction surface 196 and the shoulder surface of the plunger 132 are reduced. Therefore, in this embodiment, the magnetic force Fm is substantially constant as long as the supply current is constant, regardless of the retracted distance of the plunger 132.

It can be considered that the resistance force Fr has a magnitude corresponding to the current i supplied to the solenoid 124, similarly to the magnetic force Fm. That is, the resistance force Fr is proportional to the force with which the plunger 132 is pressed against the inner peripheral wall of the plunger chamber 170, that is, the magnitude of the orthogonal force Fn, and the magnitude of the orthogonal force Fn becomes a magnitude corresponding to the current i. It is. Therefore, the resistance force Fr is a value obtained by multiplying the current i by the coefficient B.
Resistance force Fr = coefficient B / current i (1-5)

The differential pressure Fp is a value obtained by multiplying the differential pressure ΔP by the cross-sectional area S of the ball 130. The differential pressure ΔP is a value obtained by subtracting the wheel hydraulic pressure Pw of the wheel cylinder passage 102 detected by the wheel cylinder pressure sensor 66 from the high-pressure side hydraulic pressure Ph of the pressure increasing passage 98 detected by the hydraulic pressure sensor 110. Become.
Fp = ΔP · S (1-6)
ΔP = Ph−Pw (1-7)

It is assumed that the urging force Fs has a magnitude corresponding to the backward distance X of the plunger 132. The urging force Fs in the valve closed state (X = 0) is a constant C (K: spring constant of the spring 138).
Fs = K · X + C (1-8)

  Based on the relationship described above, by adjusting the current supplied to the solenoids 80 and 90, the pressurized hydraulic fluid is supplied to the wheel cylinder 32 or the hydraulic fluid is discharged from the wheel cylinder 32. Pw can be controlled. FIG. 6 shows a flowchart of a hydraulic pressure control routine for controlling the wheel hydraulic pressure Pw. This hydraulic pressure control routine is repeatedly executed every extremely short time under the command of the main routine after the main switch of the vehicle is turned on or when the brake pedal 10 is operated.

  In step 11 (hereinafter, step 11 is abbreviated as “S11”, and the same applies to the other steps), the master cylinder pressure Pm, the hydraulic pressure Ph in the pressure increasing passage 98, and the wheel cylinder pressure Pw are hydraulic pressure sensors. 64, 110, 66 based on the detected values. Next, in S12, the hydraulic pressure target value Px of the wheel cylinder 32 is determined. The target hydraulic pressure value Px is determined based on the master cylinder pressure Pm in this embodiment. In the vehicle hydraulic brake system, when anti-lock control, traction control, regenerative braking cooperative control, or the like is performed, the hydraulic pressure target value Px can be determined by these controls.

  When the hydraulic pressure target value Px is determined, in S13 to S17, a process of increasing, decreasing or holding the hydraulic pressure of the wheel cylinder 32 is selected (details of each process are described). Will be described later). In these processes, the target current value Ia of the pressure increasing valve 80 and the target current value Ib of the pressure reducing valve 90 are determined. In other words, when the hydraulic pressure target value Px is larger than the value obtained by adding the set value E1 to the wheel cylinder pressure Pw (hereinafter sometimes referred to as “wheel hydraulic pressure Pw”), the pressure increasing process is performed ( S13, S14). Note that the set value E1 is very small compared to the maximum value of the hydraulic pressure target value Px. On the other hand, when the hydraulic pressure target value Px is smaller than the wheel hydraulic pressure Pw, a pressure reduction process is performed (S15, S16). Further, when the hydraulic pressure target value Px is not less than the wheel hydraulic pressure Pw and not more than Pw + E1 (Pw ≦ Px ≦ Pw + E1), a hydraulic pressure holding process (S17) for holding the current hydraulic pressure is performed. In S18 to S20, at least one of the storage variable Xbo used in the decompression process in S16 and the storage variable Xao used in the pressure increase process in S14 is initialized to 0, respectively. This is because, for example, when the pressure reduction process is performed after the pressure increase process is performed, the variables used in the pressure increase process are initialized and the pressure increase process is performed again.

  When the target current values Ia and Ib are determined, in S21, power is supplied to the pressure increasing valve 80 and the pressure reducing valve 90, and control is performed so that the respective opening degrees become target values. As will be described later, when one of the pressure increasing valve 80 and the pressure reducing valve 90 is opened, the other is closed.

FIG. 7 shows a flowchart of the pressure-increasing process routine in S14, which will be described along the flowchart. The pressure increasing process routine is a process of determining target current values Ia and Ib of the pressure increasing valve 80 and the pressure reducing valve 90 when the wheel hydraulic pressure Pw is increased.
First, in S31, it is determined whether or not the deviation between the hydraulic pressure target value Px and the wheel hydraulic pressure Pw is smaller than the set value H. This is because when the deviation is large, the opening degree of the pressure increasing valve 80 is maximized, and when not so, the opening degree of the pressure increasing valve 80 is made according to the deviation. For example, the opening degree is maximized when the wheel hydraulic pressure Pw is increased from near atmospheric pressure to near the maximum pressure.

When the deviation is smaller than the set value H, the target opening value Xa of the pressure increasing valve 80 is determined in S32. Note that the opening target value Xa is the retreat distance of the ball 130, that is, the retreat distance of the plunger 132. Therefore, when the opening target value Xa is 0, the plunger 132 is in the most advanced state, that is, the valve closed state. On the other hand, when the opening target value Xa is maximized, the plunger 132 is in the most retracted state. The opening target value Xa is a value obtained by multiplying the value obtained by subtracting the wheel hydraulic pressure Pw from the hydraulic pressure target value Px by the set value α, as shown in the following equation.
Xa = α · (Px−Pw) (2-1)
If the deviation is greater than or equal to the set value H, the opening target value Xa of the pressure increasing valve 80 is set to Xh (which is the maximum value of Xa) in S33.

  In S34 and S35, an old opening target value Xao (Xao is an abbreviation of Xold), which is an opening target value when this pressure increase process was executed last time, and a new opening target value Xa determined this time. Are compared. As described above, the direction in which the frictional resistance force Fr (hereinafter may be abbreviated as “resistance force Fr”) acts is reversed depending on whether the plunger 132 moves forward or backward. This is because it is desirable to change the calculation method depending on whether the opening degree increases (reverse) or decreases (forward movement) (see Expressions 1-2 and 1-3 described above).

Here, calculation of the target current value Ia when the opening degree is increasing and when the opening degree is decreasing in S36 and S37 will be described. When the opening degree is increased, the resistance force Fr acts in a direction to close the valve, that is, a direction in which the plunger 132 is advanced, as shown in the above equation (1-2). Then, when the equations (1-4) to (1-8) are substituted into the four forces (Fm, Fp, Fs, Fr) of the equation (1-2), the following equation is obtained.
A · i + ΔP · S = (K · X + C) + B · i (2-2)
By substituting the target opening value Xa for X and the target current value Ia for current i and organizing them, the target current value Ia when the opening is increased can be obtained.
Ia = (K · Xa + C−ΔP · S) / (A−B) (2-3)
The differential pressure ΔP is a value obtained by subtracting the wheel hydraulic pressure Pw from the high-pressure side hydraulic pressure Ph from the equation (1-7).
On the other hand, when the opening degree is decreased, the following formula is obtained by substituting the formulas (1-4) to (1-8) into the formula (1-3).
A · i + ΔP · S = (K · X + C) −B · i (2-4)
Similarly to the above, if the opening target value Xa and the target current value Ia are substituted and arranged, the target current value Ia when the opening is decreased can be obtained.
Ia = (K · Xa + C−ΔP · S) / (A + B) (2-5)

  If it is determined in S34 that the new opening target value Xa is larger than the value obtained by adding the set value E2 to the old opening target value Xao, the opening needs to be increased. The target current value Ia is obtained by 2-3). The set value E2 is very small compared to the maximum value of the opening target value Xa. On the other hand, when the opening target value Xa is less than the old opening target value Xao in S35, it is necessary to reduce the opening, and therefore, in S37, the target current value Ia is obtained by the above equation (2-5). .

In S38, if the difference between the new opening target value Xa and the old opening target value Xao is small, specifically, the new opening target value Xa is equal to or more than the old opening target value Xao and When it is equal to or less than the value obtained by adding the set value E2 to the old opening target value Xao (Xao ≦ Xa ≦ Xao + E2), the target current value Ia for maintaining the opening is obtained. The current value for maintaining the opening is set to an intermediate magnitude between the above formulas (2-3) and (2-5), and is half the sum of these two formulas.
Ia = A · (K · Xa + C−ΔP · S) / (A ² −B ² ) (2-6)

  In addition, when the opening degree is the same, when the three target current values Ia are compared, they increase in the order of decreasing the opening degree, maintaining the opening degree, and increasing the opening degree. For example, when a variation in the differential pressure ΔP occurs, the target current value Ia when the opening is decreased tends to decrease the opening of the valve, and the target current value Ia when the opening is increased increases the opening of the valve. It becomes easy. This is because the two target current values Ia are sized so that the opening degree of the valve can be decreased or increased against the resistance force Fr. However, since the resistance force Fr suppresses the forward movement of the plunger 132 in a state where the target current value Ia at the time when the opening is increased is supplied, the self-excited vibration is hardly generated and is attenuated even if the self-excited vibration is generated. The In addition, in the state where the target current value Ia when the opening is decreased is supplied, the resistance force Fr suppresses the backward movement of the plunger 132, so that self-excited vibration is difficult to occur, and even if self-excited vibration occurs, it is attenuated. It is done. On the other hand, since the target current value Ia at the time of maintaining the opening is not set to a magnitude that can increase or decrease the opening of the valve against the resistance force Fr, the resistance force Fr suppresses the forward and backward movement of the plunger 132. As a result, self-excited vibration is less likely to occur.

In S39, when the deviation (Px−Pw) exceeds the set value H (S31), the target current value Ia that maximizes the opening degree is determined. In this case, in the above equation (2-3), the target value Xh of the maximum opening is substituted for the opening target value Xa (S33), and the auxiliary current value Ih is further added to obtain the following equation. Then, the opening is increased to the maximum speed quickly and reliably by adding the auxiliary current value Ih.
Ia = Ih + (K · Xa + C−ΔP · S) / (A−B) (2-7)

When the target current value Ia is determined by the processing described above, the current opening target value Xa is recorded in the old opening target value Xao in S40 (S40). In S41, the target current value Ib of the pressure reducing valve 90 is set to a valve closing current value I ₀ that is a current value for closing the valve. The valve closing current value I ₀ is set to ₀ in this embodiment. In order to increase the opening quickly while maintaining the valve closing state, the valve closing current value I ₀ can be supplied with a certain amount of current. For example, in the above formula (2-5), it is possible to supply a current smaller than the current value where Xa = 0.

FIG. 8 shows a flowchart of the decompression process routine of S16, and the explanation will be made along the flowchart. The pressure reducing process routine is a process for determining target current values Ia and Ib of the pressure increasing valve 80 and the pressure reducing valve 90 when the wheel hydraulic pressure Pw is decreased. Since this decompression processing routine has many parts similar to the above-described pressure increase processing routine, different parts will be mainly described.
In S51, it is determined whether the hydraulic pressure target value Px is set to atmospheric pressure (= 0) and the wheel hydraulic pressure Pw is smaller than the set pressure U. If the determination in S51 is No, that is, if the hydraulic pressure target value Px is not atmospheric pressure, or if the wheel hydraulic pressure Pw is sufficiently larger than the atmospheric pressure, the opening of the pressure reducing valve 90 is determined in S52. Target value Xb is determined based on the following equation. In the following equation, β is a set value.
Xb = β · (Pw−Px) (3-1)
On the other hand, if the determination in S51 is Yes, that is, if the wheel hydraulic pressure Pw is reduced to atmospheric pressure, the opening target value Xb is set to the set opening Xu in S53. The set opening degree Xu is an opening degree at which the wheel hydraulic pressure Pw can be reduced relatively smoothly even when the wheel hydraulic pressure Pw is close to the atmospheric pressure.

The processing of S54 to S58 is the same as the processing of S34 to S38 in the above-described pressure increase processing routine. The opening target value Xa is changed to Xb, the old opening target value Xao is changed to Xbo, and the target current value Ia is changed to Ib. Below, the formula used by S56-S58 is shown.
Ib = (K · Xb + C−ΔP · S) / (A−B) (3-2)
Ib = (K · Xb + C−ΔP · S) / (A + B) (3-3)
Ib = A · (K · Xb + C−ΔP · S) / (A ² −B ² ) (3-4)
Note that the differential pressure ΔP in the decompression process is a value obtained by subtracting the atmospheric pressure from the wheel hydraulic pressure Pw, that is, the same value as the wheel hydraulic pressure Pw. In addition, the value of the spring constant K of the spring 138 may be different between the pressure increasing valve 80 and the pressure reducing valve 90.
In S59, the target current value Ib for reducing the wheel hydraulic pressure Pw to atmospheric pressure is determined based on the above equation (3-2).
The processes of S60 and S61 are the same as the processes of S40 to S41 in the above-described pressure increasing process routine.

Here, the hydraulic pressure holding process routine of S17 will be described.
This process is a process for determining the target current values Ia and Ib so that the wheel hydraulic pressure Pw does not change when the difference between the hydraulic pressure target value Px and the wheel hydraulic pressure Pw is very small. In this embodiment, the target current values Ia and Ib are both set to the valve closing current value I ₀ , and both the pressure increasing valve 80 and the pressure reducing valve 90 are closed. The valve closing current value I ₀ is 0 or a current value that can maintain the valve closing state.

  By the hydraulic pressure control described above, the wheel hydraulic pressure Pw is controlled and the vehicle is braked. In the hydraulic pressure control, the valve opening is set to an intermediate state. However, since the above-described resistance force Fr acts on the plunger 132, for example, even if a vibration factor such as a variation in differential pressure occurs, the plunger 132 does not move, or the moving distance becomes relatively small, and self-excited vibration is suppressed. Further, the resistance force Fr has a magnitude corresponding to the current supplied to the solenoid 124 as described above, and therefore the resistance force Fr increases in a relatively large opening where self-excited vibration is likely to occur. The resistance force Fr becomes small at a relatively small opening at which self-excited vibration hardly occurs. That is, the self-excited vibration can be effectively suppressed.

In the present embodiment, the convex portion 200 is formed continuously with the plunger main body 172, but may be formed of a separate member. For example, a thin plate-like member having ferromagnetism can be fixed to the plunger main body 172 by bonding or the like, or a part of the sleeve 174 can be made a thin plate-like member having ferromagnetism.
In the present embodiment, the convex portion 200 is disposed at the center of the plunger main body 172 in the axial direction, but may be disposed on the ball 130 side or the spring 138 side.

FIG. 9 shows an “electromagnetic valve that applies an orthogonal force by an elastic body”, which is another example of the above-described “electromagnetic valve that biases magnetic force”.
The electromagnetic valve 300 is provided at any one of the pressure increasing valves 80 to 86 or the pressure reducing valves 90 and 92 in the hydraulic brake system (FIG. 1) similar to the above embodiment. In addition, since the electromagnetic valve 300 is configured in many parts in the same manner as the electromagnetic valve 80 in the above embodiment, the same components are denoted by the same reference numerals and the description thereof is omitted, and different parts are mainly described. explain.

In the electromagnetic valve 300, the plunger 310 includes an elastic force generation mechanism 320 that generates an orthogonal force that is a force in a direction orthogonal to the reciprocating same direction by an elastic body. The elastic force generating mechanism 320 is accommodated in the plunger body 330 in an accommodation hole 332 provided in an orthogonal direction perpendicular to the direction in which the plunger 310 reciprocates. The accommodation hole 332 has a circular cross-sectional shape.
The elastic force generation mechanism 320 includes a disc spring 336 having a circular planar shape as an elastic member, and the disc spring 336 is disposed in the receiving hole 332 with the recess side facing the bottom surface thereof. Yes. The elastic force generation mechanism 320 includes a rolling ball 340 that is a “rotating body” rotatably accommodated on the convex side of the disc spring 336 in the accommodation hole 332, and a slip between the rolling ball 340 and the disc spring 336. And a friction reducing member 342 for reducing friction. The rolling ball 340 is formed of a nonmagnetic material having a lower hardness than the inner peripheral wall of the plunger chamber 170. If the friction reducing member 342 has a shape and dimensions that can increase the contact area between the rolling ball 340 and the disc spring 336 as compared with the case where the rolling ball 340 and the disc spring 336 are in direct contact with each other, the effect can be obtained. It is desirable that at least the contact surface with the rolling ball 340 is formed of a material having a low friction coefficient such as polytetrafluoroethylene.

  A part of the rolling ball 340 protrudes from the outer periphery of the plunger 310 when the disc spring 336 is not deformed. Therefore, in a state where the plunger 310 is fitted in the plunger chamber 170, the disc spring 336 is elastically deformed by being sandwiched between the rolling ball 340 pressed against the inner peripheral wall of the plunger chamber 170 and the bottom surface of the accommodation hole 332. It is done. The disc spring 336 generates an elastic force substantially corresponding to the amount of elastic deformation, and presses the rolling ball 340 against the inner peripheral wall of the plunger chamber 170. The elastic force that presses the rolling ball 340 against the inner peripheral wall of the plunger chamber 170 is a force that urges the plunger 310 and the inner wall of the plunger chamber 170 in the orthogonal direction. As a result, the plunger 310 is pushed in the direction opposite to the side where the accommodation hole 332 is provided, and the frictional resistance between the side surface of the plunger 310 and the inner peripheral wall of the plunger chamber 170 increases in the opposite direction. On the other hand, when the plunger 310 reciprocates in the plunger chamber 170, the rolling ball 340 rolls on the inner peripheral wall of the plunger chamber 170, so the frictional resistance between the rolling ball 340 and the inner peripheral wall of the plunger chamber 170 is small. It will be a thing.

In the solenoid valve 300, when a current is supplied to the solenoid 124, the force acting on the plunger 310 is substantially the same as that of the solenoid valve 80 described above. Fm is a magnetic force, Fp is a differential pressure, Fs is an urging force, and Fr is a resistance force.
[When opening degree increases] Fm + Fp = Fs + Fr (4-1)
[When the opening degree is decreased] Fm + Fp = Fs−Fr (4-2)
Therefore, in the hydraulic brake system in which the electromagnetic valve 300 is provided, the same hydraulic pressure control (FIGS. 6 to 8) as in the above embodiment is performed. However, the electromagnetic valve 300 differs from the electromagnetic valve 80 in that the magnitude of the resistance force Fr does not change depending on the magnitude of the supply current. The magnitude of the resistance force Fr of the electromagnetic valve 300 is a magnitude corresponding to the elastic force generated by the disc spring 336 and is substantially constant. Therefore, in the pressure increasing process of the hydraulic pressure control (FIG. 7), the above formulas (2-3), (2-5), (2-6), (2-7) for determining the target current value Ia are: Each is as follows.
Ia = (K · Xa + C−ΔP · S + R) / A (4-3)
Ia = (K · Xa + C−ΔP · S−R) / A (4-4)
Ia = (K · Xa + C−ΔP · S) / A (4-5)
Ia = Ih + (K · Xa + C−ΔP · S + R) / A (4-6)
The above equation (4-3) is the target current value when the opening is increased, the equation (4-4) is the target current value when the opening is decreased, and the equation (4-5) is the target current value when maintaining the opening. (4-6) is for obtaining the target current value at the maximum opening. The variable R is the magnitude of the resistance force Fr.
Further, in the pressure reducing process (FIG. 7) of the hydraulic pressure control, the above-described formulas (3-2), (3-3), and (3-4) for determining the target current value Ib are as follows.
Ib = (K · Xb + C−ΔP · S + R) / A (4-7)
Ib = (K · Xb + C−ΔP · S−R) / A (4-8)
Ib = (K · Xb + C−ΔP · S) / A (4-9)

Also in the electromagnetic valve 300, self-excited vibration is suppressed by frictional resistance in substantially the same manner as the electromagnetic valve 80. Unlike the electromagnetic valve 80, the electromagnetic valve 300 does not reduce the frictional resistance when the opening is small, but has an advantage that the frictional resistance can be generated without consuming electric power.
In the two embodiments described above, the current supplied to the solenoid 124 is increased when the opening is decreased and when the opening is decreased in consideration of the direction of frictional resistance between the plunger 132 or 310 and the inner wall of the plunger chamber 170. However, it is not indispensable, and is determined based on the same equation when the opening is increased and when the opening is decreased. It is also possible.

In the electromagnetic valves of the above two embodiments, self-excited vibration is suppressed by applying a force in the orthogonal direction to the plunger, but “a solenoid valve that allows a relatively large movement of the tip of the plunger in the orthogonal direction” Can also suppress self-excited vibration.
First, how the ball 130 as the valve moves when the seat valve 122 opens and closes will be described. FIG. 10 schematically shows the movement of the ball 130 by enlarging the ball 130 and the valve seat 128. In order to make the movement of the ball 130 easier to understand, the movement amount of the ball 130 is exaggerated. In the valve-closed state indicated by the two-dot chain line, the ball 130 is in contact with the valve seat 128 along one circumference and closes the second port 164 which is a high-pressure side hydraulic pressure passage. When the seat valve 122 is opened, the ball 130 indicated by a solid line is moved in a direction in which the plunger 310 is retracted, that is, retracted. However, the valve seat 128 is not contacted immediately after the start of retreating, and often moves obliquely along the tapered surface of the valve seat 128 at the beginning of retreat. This is presumed to be due to the fact that the ball 130 is moved toward one side in the radial direction by the hydraulic fluid flowing into the valve chamber 178 through the gap between the ball 130 and the valve seat 128. When the ball 130 is further retracted, the movement of the ball 130 and the plunger 310 in the orthogonal direction is restricted by the inner wall of the plunger chamber 170, so that the ball 130 moves away from the valve seat 128 as indicated by a dotted line.

  In the state where the above-described ball 130 is in contact with the valve seat 128, even if a force that vibrates the ball 130 and the plunger 310 in the reciprocating direction is generated, the forward movement of the ball 130 and the plunger 310 is hindered, so that self-excited vibration hardly occurs. On the other hand, when the ball 130 moves away from the valve seat 128, the ball 130 and the plunger 310 easily reciprocate, and self-excited vibration is likely to occur. Note that, in a state where the thin plate 194 of the plunger 310 is in contact with the suction surface 196, the plunger 310 is prevented from moving backward, so that self-excited vibration is less likely to occur. In view of the above events, if the solenoid valve can be opened while the ball 130 is in contact with the valve seat 128 until the retraction of the plunger is restricted, the self-excited vibration Can be suppressed.

As shown in FIG. 11, when the ball 130 is retracted to some extent, the movement of the plunger distal end portion and the proximal end portion in the orthogonal direction is restricted by the inner peripheral wall of the plunger chamber 170 (the black surfaces facing each other). This is because the movement of the ball 130 in the orthogonal direction is limited by the force of either one of the arrows.
On the other hand, the electromagnetic valve 400 shown in FIG. 12 intentionally allows a relatively large movement of the distal end portion of the plunger in the orthogonal direction. The electromagnetic valve 400 is provided at any one of the pressure increasing valves 80 to 86 or the pressure reducing valves 90 and 92 in the hydraulic brake system (FIG. 1) similar to the first embodiment. In addition, since the electromagnetic valve 400 has the same configuration as that of the electromagnetic valve 80 of the first embodiment, the same components are denoted by the same reference numerals and description thereof is omitted, and different portions are mainly described. Explained.

  The solenoid valve 400 is configured to allow movement of the plunger 410 in the orthogonal direction on the tip end side (ball 130 side). On the base end side (spring 138 side) of the plunger 410 of the solenoid valve 400, a regulated portion (straight portion) 420 whose outer diameter is made uniform and movement in the orthogonal direction is regulated by the inner peripheral wall of the plunger chamber 170. Is provided. On the other hand, the portion of the plunger 410 closer to the tip than the regulated portion 420 has a tapered portion 422 that is tapered so that the outer diameter becomes smaller toward the tip (in the drawing, the taper angle is exaggerated). There is). Therefore, compared with the conventional solenoid valve, the tip of the plunger 410, that is, the ball 130, can move more greatly in the orthogonal direction. The gap between the plunger 410 and the inner wall of the plunger chamber 170 is smaller between the regulated portion 420 and the spacer 154 than the other portions, and the plunger 410 tilts around the fitting portion with the spacer 154. The movement of the ball 130 in the orthogonal direction is mainly permitted by this tilting.

  FIG. 13 shows a state where the plunger 410 is retracted until it comes into contact with the suction surface 196. The tip of the plunger 410 is allowed to move in the orthogonal direction as indicated by the white arrow. When the ball 130 comes into contact with the valve seat 128, the movement of the tip of the plunger 410 in the orthogonal direction is restricted. As described above, the electromagnetic valve 400 is configured to be able to move obliquely while the ball 130 is in contact with the valve seat 128 from when the plunger 410 starts to move backward until the backward movement is regulated. .

Note that the control of the hydraulic brake system including the electromagnetic valve 400 is substantially the same as in the first embodiment. Below, it demonstrates simply centering on a different part.
In this solenoid valve 400, when a current is supplied to the solenoid 124, the force acting on the plunger 410 is substantially the same as that of the solenoid valve 80 described above, but no resistance force acts when the opening is increased. The point is different. In the following equation, Fm is a magnetic force, Fp is a differential pressure, Fs is an urging force, and Fr is a resistance force.
[When opening degree increases] Fm + Fp = Fs (5-1)
[When the opening is decreasing] Fm + Fp = Fs−Fr (5-2)
Therefore, in the hydraulic brake system in which the electromagnetic valve 400 is provided, the same hydraulic pressure control (FIGS. 6 to 8) as in the above embodiment is performed. In the pressure increasing process (FIG. 7) of the hydraulic pressure control, the above formulas (2-3), (2-5), (2-6), and (2-7) for determining the target current value Ia are respectively become that way.
Ia = (K · Xa + C−ΔP · S) / A (5-3)
Ia = (K · Xa + C−ΔP · S−Z) / A (5-4)
Ia = (K · Xa + C−ΔP · S−Z / 2) / A (5-5)
Ia = Ih + (K · Xa + C−ΔP · S) / A (5-6)
The above equation (5-3) is the target current value when the opening is increased, the equation (5-4) is the target current value when the opening is decreased, the equation (5-5) is the target current value when maintaining the opening, and the equation (5-6) is for obtaining the target current value at the maximum opening. The variable Z is the magnitude of the resistance force Fr.
Further, in the pressure reducing process (FIG. 7) of the hydraulic pressure control, the above-described formulas (3-2), (3-3), and (3-4) for determining the target current value Ib are as follows.
Ib = (K · Xb + C−ΔP · S) / A (5-7)
Ib = (K · Xb + C−ΔP · S−Z) / A (5-8)
Ib = (K · Xb + C−ΔP · S) / A (5-9)

In the electromagnetic valve 400, a resistance force is generated with respect to the forward movement of the plunger 410, but a resistance is hardly generated with respect to the backward movement. However, when a force for vibrating the plunger 410 is generated, the forward movement of the plunger 410 is suppressed, so that self-excited vibration is suppressed. Unlike the electromagnetic valve 80, the electromagnetic valve 400 does not reduce the frictional resistance when the opening is small, but has an advantage that the frictional resistance can be generated without consuming electric power.
In this embodiment as well, in the same manner as in the two embodiments described above, in consideration of the effect of resistance caused by the contact of the ball 130 with the valve seat 128, the supply current to the solenoid 124 is increased and decreased when the opening is increased. However, it is not indispensable and is determined based on the same equation when the opening is increased and when the opening is decreased. It is also possible to do so. In addition, although the resistance due to the ball 130 coming into contact with the valve seat 128 acts when the opening degree decreases and the resistance does not act when the opening degree increases, the supply current to the solenoid 124 is determined. The current supplied to the solenoid 124 can be determined on the assumption that the resistance acts both when the degree is increased and when the opening degree is decreased. In addition, the magnitude | size of resistance at the time of opening degree increase and the time of opening degree reduction can be made the same or different.

  Note that the ball 130 can be held by the ball holder 175 so as to be rotatable or non-rotatable. If the ball 130 is held rotatably, it is possible to avoid slipping when the ball 130 moves along the valve seat 128, and to reduce wear of both. In particular, since the portion of the ball 130 that contacts the valve seat 128 changes due to rotation, local wear can be avoided, which is very advantageous in improving durability. On the other hand, if the ball 130 is held non-rotatably by the ball holder 175, the self-excited vibration of the plunger 410 is more effectively suppressed by the frictional force when the ball 130 moves along the valve seat 128. can do.

  In the present embodiment, a portion of the inner peripheral wall of the plunger chamber 170 that restricts the movement of the restricted portion 420 in the orthogonal direction functions as an “orthogonal movement restricting portion”. Further, the tapered portion 422 functions as an “orthogonal movement allowing portion”. Furthermore, it includes an orthogonal movement restricting portion, an orthogonal movement allowing portion, and a valve seat 128 structured so that the ball 130 can come into contact until the retraction of the plunger 132 is restricted. Is configured.

  <Solenoid valve that imparts orthogonal force by biasing magnetic force> 10: Brake pedal 12: Master cylinder device 14: Brake actuator 18: Master cylinder 20, 22: Pressurizing chamber 24, 26: Liquid passage 28: Left front wheel 30 : Right front wheel 32: Wheel cylinder 34: Wheel cylinder 36: Reservoir 40: Electromagnetic on-off valve 46: Left rear wheel 48: Right rear wheel 56: Master cut valve 58: Master cut valve 60: Power hydraulic pressure source 62: Hydraulic pressure control Valve device 64: Master cylinder pressure sensor 66: Wheel cylinder pressure sensor 80, 82, 84, 86: Pressure increasing electromagnetic hydraulic pressure control valve (electromagnetic valve) 90, 92, 94, 96: Pressure reducing electromagnetic hydraulic pressure control valve (electromagnetic) Valve) 98: pressure increasing passage 100: pressure reducing passage 102, 104, 106, 108: hoi Cylinder passage 110: Fluid pressure source fluid pressure sensor 120: Valve housing (housing) 122: Seat valve 124: Solenoid 128: Valve seat 130: Ball (valve element) 132: Plunger 138: Spring (elastic body) 144: First magnet Path forming member 146: Second magnetic path forming member 150: First member 152: Second member 154: Spacer 158: First port 162: Third member 164: Second port 170: Plunger chamber 172: Plunger body 174: Sleeve 176: Clearance 190: Through hole 192: Communication path 194: Thin plate 196: Suction surface (contact portion) 200: Convex portion 202: Notch portion 250: ECU (electronic control unit) <Electromagnetic valve that applies orthogonal force by elastic body > 300: Solenoid valve 10: Plunger 320: Elastic force generation mechanism (elastic body) 332: Accommodating hole 336: Belleville spring 340: Rolling ball 342: Friction reducing member <Solenoid valve allowing the plunger tip to move in the orthogonal direction> 400: Solenoid valve 410: Plunger 420: Restricted portion 422: Tapered portion

Claims (5)

A housing in which a high-pressure side liquid passage and a low-pressure side liquid passage are connected, and the high-pressure side liquid passage and the low-pressure side liquid passage communicate with each other;
A plunger provided in the housing so as to be capable of reciprocating in the axial direction;
A valve element held at the tip of the plunger;
A valve seat which is formed in a tapered shape extending toward the valve element at a position facing the valve element of the housing, and the liquid passage on the high pressure side is opened so as to be closed by the valve element;
An elastic body that biases the plunger toward the valve seat or away from the valve seat;
A solenoid that generates a magnetic force that moves the plunger in a direction opposite to the direction in which the elastic body is biased;
A suppression force applying device that applies a force to suppress reciprocation of the plunger,
The restraining force applying device is
An orthogonal direction movement restricting portion that is provided in the housing and restricts the movement of the base end portion, which is the portion opposite to the tip end portion of the plunger, in the orthogonal direction that is perpendicular to the reciprocating direction of the plunger. When,
A valve for allowing the valve element to come into contact with the valve seat even when the plunger is retracted to the maximum extent. A solenoid valve comprising a child valve seat contact allowing mechanism.   The valve-valve seat contact allowing mechanism is provided in at least one of the plunger and the housing, and gradually increases the clearance between the plunger and the housing in the direction from the proximal end portion to the distal end portion of the plunger. The electromagnetic valve according to claim 1, comprising:   A straight portion with a uniform outer diameter is provided at the base end portion of the plunger as a restricted portion whose movement in the orthogonal direction is restricted by the inner peripheral wall of the housing, and a portion on the tip side of the straight portion is at the tip. 3. The electromagnetic wave according to claim 2, wherein a taper portion having a taper in a direction in which an outer diameter becomes smaller as it approaches is closer, and the plunger can tilt around a fitting portion between the restricted portion and the inner peripheral wall of the housing. valve.   The plunger is made of a ferromagnetic material, and forms a magnetic path in cooperation with a portion of the housing made of the ferromagnetic material, while the inner peripheral wall of the housing fitted with the straight portion of the plunger is a non-magnetic material. The solenoid valve according to claim 3, which is formed by a spacer made of metal. 5. The electromagnetic valve according to claim 1, wherein the solenoid valve is a normally closed valve, and a magnetic path forming member that is a component of the solenoid includes a contact portion that contacts the plunger and defines a retreat limit of the plunger. The solenoid valve according to the above.

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