Solenoid valve

Abstract

The present invention provides a solenoid valve capable of improving the responsiveness of the solenoid valve. A solenoid valve (1) is provided, wherein a plunger (34) is arranged in a storage space (30) inside a solenoid portion (3), and the solenoid valve (1) comprises: a first breathing flow path (103) extending circumferentially on the outer periphery of a stator (33) and communicating with the outside of the solenoid valve (1); a second breathing flow path (104) extending axially from a portion of the circumference of the first breathing flow path (103) and communicating with a first space (S1) formed between the stator (33), a sleeve (21) and a slide column (22); and a third breathing flow path (105) extending axially on the inner periphery of the stator (33) and communicating between the first space (S1) and the second space (S2).

Description

Technical Field

[0001] The present invention relates to a solenoid valve, in particular to a solenoid valve suitable for hydraulic control of a hydraulic circuit. Background Art

[0002] An existing solenoid valve for hydraulic control comprises: a valve portion having a sleeve, a slide rod housed in the sleeve and movable axially, a spring applying axial force to the slide rod, and a retainer mounted on the end of the sleeve and retaining the spring; and a solenoid portion having a plunger for axially driving the slide rod, a stator, a solenoid molded body arranged on the outer periphery of the plunger and having a coil covered with resin, and a solenoid housing for accommodating them. The solenoid valve is arranged between a pressure source such as a pump or an accumulator and a supply destination, and can supply a fluid with adjusted pressure and flow to the supply destination by moving the slide rod.

[0003] However, the spool has a large movement stroke in the sleeve. Therefore, when the spool is driven in the axial direction, the fluid inside the accommodation space for accommodating the plunger in the solenoid portion may act as resistance and hinder the rapid movement of the plunger.

[0004] The solenoid valve in Patent Document 1 has a radially penetrating breathing hole formed on the sleeve. By allowing the fluid to move between the inside of the storage space and the outside of the solenoid valve through the breathing hole, which is called breathing, the resistance generated by the fluid accompanying the movement of the plunger is reduced and the responsiveness of the solenoid valve is improved.

[0005] Prior art literature

[0006] Patent Literature

[0007] Patent Document 1: International Publication No. 2011 / 052371 (page 7, Figure 1 ) Summary of the Invention

[0008] Problems to be solved by the invention

[0009] In such a solenoid valve, the movement of the plunger, which drives the spool axially, allows fluid to move between the interior of the housing and the exterior of the solenoid valve through a breathing hole formed in the sleeve, thereby reducing the resistance generated by the fluid accompanying the movement of the plunger. However, in the solenoid valve of Patent Document 1, the breathing hole formed in the sleeve penetrates radially and communicates with the outer peripheral space of the spool. As a result, the spool is susceptible to the flow and pressure of the fluid during inflow, causing the spool to tilt relative to the sleeve, reducing its sliding properties and potentially degrading the responsiveness of the solenoid valve.

[0010] The present invention has been made in view of such problems, and an object of the present invention is to provide a solenoid valve capable of improving the responsiveness of the solenoid valve.

[0011] Means for solving problems

[0012] In order to solve the above problems, the solenoid valve of the present invention comprises:

[0013] The valve portion includes a sleeve that accommodates a spool in an axially movable manner; and a solenoid portion includes a plunger that contacts or separates from a stator by electromagnetic force and drives the spool in the axial direction, a solenoid molded body arranged on the outer periphery of the plunger and the stator, and a solenoid housing that accommodates the solenoid molded body.

[0014] The plunger is arranged inside the solenoid portion in a housing space at least partially partitioned by the stator.

[0015] The solenoid valve comprises: a first breathing flow path extending at least in a circumferential direction on the outer periphery of the stator and communicating with the outside of the solenoid valve;

[0016] a second breathing flow path extending axially from the first breathing flow path over a portion of the circumference thereof and communicating with a first space formed between the stator, the sleeve, and the slide post; and

[0017] The third breathing flow path extends in the axial direction on the inner periphery of the stator and connects the first space with the storage space.

[0018] As a result, when fluid moves from the outside to the inside of the solenoid valve in the breathing path due to the movement of the plunger, the fluid flows from the first breathing path on the outer circumference of the stator through a second breathing path extending axially over a portion of the circumference to the first space. As a result, the fluid moving axially from the second breathing path is dispersed within the first space, weakening its flow. This reduces the radial impact of the fluid, maintains the coaxiality of the slide and sleeve, and maintains smooth sliding of the slide relative to the sleeve, thereby improving the responsiveness of the solenoid valve. Furthermore, the first and second breathing paths allow the breathing path to be lengthened, making it difficult for contaminants outside the solenoid valve to enter the storage space.

[0019] The first breathing flow path may be formed in an annular shape and communicate with the outside of the solenoid valve through an axial communication path extending in the axial direction toward an opening formed in the solenoid case or the sleeve.

[0020] Thus, the breathing passage can be made longer by the first breathing flow path and the axial communication path, and therefore, contaminants existing outside the solenoid valve are less likely to enter the housing space.

[0021] The second breathing flow path may communicate with the first space on an outer diameter side of the spool.

[0022] Thus, the fluid that moves in the axial direction in the second breathing flow path and flows out into the first space mainly exerts an axial force on the sleeve, and thus is less likely to affect the movement of the spool.

[0023] The second respiratory flow path and the axial communication path may be opposed to each other in the radial direction.

[0024] Thus, contaminants that have entered the first respiratory flow path from outside the solenoid valve through the axial communication path are less likely to enter the second respiratory flow path.

[0025] Alternatively, the axial communication path may be formed vertically below the outer circumference of the stator.

[0026] This facilitates fluid outside the solenoid valve to flow into the first breathing flow path through the axial communication path, and contaminants that enter the first breathing flow path along with the fluid can be lowered by their own weight and easily discharged to the outside through the axial communication path.

[0027] A radial groove for connecting the second breathing flow path and the third breathing flow path may be formed in the stator or the slide post.

[0028] Thus, regardless of the axial position of the spool, the radial groove always connects the second respiratory flow path and the third respiratory flow path. This prevents movement of the fluid in the respiratory path from being hindered, thereby reducing resistance generated by the fluid accompanying movement of the plunger. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 is a perspective view showing a solenoid valve in an embodiment of the present invention;

[0030] Figure 2 The closed state of the solenoid valve of the embodiment is shown. Figure 1 AA line cross-sectional view;

[0031] Figure 3 The diagram shows the open state of the solenoid valve of the embodiment. Figure 1 AA line cross-sectional view;

[0032] Figure 4 is a perspective view showing the structure of a sleeve and a solenoid housing of an embodiment;

[0033] Figure 5 is a perspective view showing the structure of a stator of the embodiment;

[0034] Figure 6 : is an enlarged cross-sectional view showing the flow of fluid in the breathing path when the electromagnetic valve is switched from the closed state to the open state. Figure 6 shows the situation where the fluid moves from the inside to the outside of the solenoid valve;

[0035] Figure 7 : is an enlarged cross-sectional view showing the flow of fluid in the breathing path when the electromagnetic valve is switched from the open state to the closed state. Figure 7 shows the situation where the fluid moves from the outside to the inside of the solenoid valve;

[0036] Figure 8 (a) shows the flow of fluid in the respiratory path when the electromagnetic valve is switched from the closed state to the open state. Figure 2 (b) is a cross-sectional view of the line BB, showing the flow of the fluid in the breathing path when the electromagnetic valve is switched from the open state to the closed state. Figure 3 BB line cross-sectional view. DETAILED DESCRIPTION

[0037] Hereinafter, specific embodiments of the solenoid valve of the present invention will be described based on examples.

[0038] Example

[0039] Reference Figures 1 to 8 The electromagnetic valve of the embodiment will be described. Figure 2 and Figure 3 The left and right sides when viewed from the front side are described as the left and right sides of the solenoid valve. In addition, for the sake of convenience, Figure 2 、 Figure 3 、 Figure 6 and Figure 7 The spool 22 , plunger 34 , and rod 35 are shown in side view rather than in cross-section.

[0040] The solenoid valve 1 is a spool-type solenoid valve used in hydraulically controlled equipment such as an automatic transmission of a vehicle to control the pressure and flow of a control fluid (hereinafter referred to as "fluid") such as hydraulic oil in a fluid circuit.

[0041] like Figure 1 As shown, the electromagnetic valve 1 is configured such that a valve portion 2, which serves as a valve to adjust the pressure and flow rate of a fluid, is integrally mounted on a solenoid portion 3. Attachment of the valve portion 2 to the solenoid portion 3 will be described in detail later.

[0042] like Figure 2 and Figure 3 As shown, the valve portion 2 consists of the following components: a generally cylindrical sleeve 21; a generally cylindrical spool 22, fluid-tightly housed in a through-hole 21a of the sleeve 21 and axially movable; a coiled spring 23, attached to the axially right end of the spool 22 and biasing the spool 22 axially leftward; and a retainer 24, riveted to the axially right end of the sleeve 21 and retaining the spring 23. This structure is well-known for spool valves, so a detailed description will be omitted. The sleeve 21, spool 22, and retainer 24 are formed from materials such as aluminum, iron, stainless steel, and resin.

[0043] like Figure 2 and Figure 3 As shown, at the axial left end portion of the sleeve 21, a pair of axial sections 21f, 21f formed in the axial direction and a pair of radial sections 21g, 21g formed in the radial direction are formed on the upper and lower sides. Figure 4 As shown, the axial sections 21f, 21f form a pair of straight sections when viewed from the axial direction, and the arc-shaped portion extending along the outer diameter side between the pair of axial sections 21f, 21f forms a pair of arc sections 21b, 21b, thereby forming the axial left end portion of the sleeve 21 into a stadium shape. In addition, for the convenience of explanation, Figure 4 , a state is shown in which the axial left end portion of the sleeve 21 faces upward on the paper.

[0044] A slit 21d extending circumferentially is formed at the axially left end of the sleeve 21, at a location axially away from the stadium-shaped end surface 21m. A flange portion 21c is formed between the end surface 21m and the slit 21d. Furthermore, the axial sections 21f, 21f are formed into a substantially H-shaped surface due to the formation of the slit 21d.

[0045] In addition, the axial section 21f (see FIG. 21f ) is arranged vertically downward in a state where the valve section 2 is mounted on the solenoid section 3. Figure 2 and Figure 3 ) is formed with a cutout 21h extending axially from the end face 21m as an opening. In addition, the cutout 21h has a tapered surface 21k (see Figure 6 and Figure 7 ).

[0046] In addition, a recessed portion 21e is formed at the axial left end portion of the sleeve 21, which is recessed axially rightward from the inner diameter side of the end surface 21m. The inner diameter D1 of the recessed portion 21e is formed to be larger than the inner diameter D2 of the through hole 21a at the portion that comes into sliding contact with the shoulder portion 22a of the spool 22 (D1>D2, see Figure 2 ).

[0047] like Figure 2 and Figure 3 As shown, a small-diameter protrusion 22b is formed at the axially left end of the spool 22. This small-diameter protrusion 22b protrudes axially leftward from the inner diameter side of the shoulder portion 22a and is inserted into a through-hole 33a of a stator 33, which will be described later. The end surface of the protrusion 22b, that is, the axially left end surface of the spool 22, abuts the axially right end surface of the rod 35 disposed in the through-hole 33a of the stator 33.

[0048] Furthermore, at the axially left end of the spool 22, an annular step 22c is formed by the outer circumferential surface of the protrusion 22b, the axially left end surface of the shoulder 22a, and the outer circumferential surface of the shoulder 22a. The step 22c is capable of contacting and separating from the end surface of the protrusion 33d of the stator 33, which will be described later.

[0049] like Figure 2 and Figure 3 As shown, the solenoid portion 3 is mainly composed of the following parts: a solenoid shell 31, which is formed of a magnetic metal material such as iron; a solenoid molded body 32, which is housed in the solenoid shell 31; a stator 33, which is arranged on the inner side of the solenoid molded body 32; and a plunger 34, which is arranged in a state of being movable in the axial direction in a housing space 30 formed on the axial left side of the stator 33.

[0050] like Figure 4 As shown, the solenoid housing 31 is in the shape of a cover having a circular plate portion 31a and a cylindrical portion 31b. A stadium-shaped opening 31d is formed in the center of the plate portion 31a. The solenoid housing 31 is slightly larger than the axial left end portion of the sleeve 21 and is composed of a straight portion 31e and an arc portion 31f. In addition, for the sake of convenience, Figure 4 , a state is shown in which the axial right end portion of the solenoid housing 31 faces upward in the paper.

[0051] In addition, the solenoid housing 31 has an end plate 39 fixed by riveting to the axial left end portion of the cylindrical portion 31b (see Figure 2 and Figure 3 ). In addition, a connector portion 32c for the solenoid molded body 32 is formed at the axial left end portion of the cylindrical portion 31b (see Figure 2 and Figure 3 ) is inserted through the incision 31c.

[0052] Regarding the installation of the valve portion 2 to the solenoid portion 3, the flange portion 21c of the sleeve 21 is inserted into the opening 31d of the solenoid housing 31, and the sleeve 21 is rotated 90 degrees around the axis at a position where the slit 21d corresponds to the opening 31d. This prevents the sleeve 21 from being separated from the solenoid housing 31 with the straight portions 31e, 31e of the opening 31d being sandwiched between the slit 21d (see FIG. 2 ). Figure 1 ).

[0053] like Figure 2 and Figure 3 As shown, the solenoid molded body 32 is formed by molding the coil 32a, the annular lower plate 32b, etc. with resin, and the control current is supplied to the coil 32a from the connector of the connector part 32c, wherein the connector part 32c is connected from the cutout 31c of the solenoid housing 31 (see Figure 4 ) extends outward.

[0054] like Figure 2 and Figure 3 As shown, the plunger 34 is formed into a cylindrical shape by a magnetic metal material such as iron, and is arranged in an axially movable manner in the housing space 30 formed on the axially left side of the stator 33 .

[0055] Furthermore, a first cylindrical body 36 made of a non-magnetic material is disposed on the axially left side of the stator 33, a second cylindrical body 37 made of a magnetic material and having a flange is disposed on the axially left side of the first cylindrical body 36, and a third cylindrical body 38 made of a magnetic material is disposed inside the first and second cylindrical bodies 36, 37, so as to span the first and second cylindrical bodies 36, 37. Specifically, the storage space 30 is defined by a recessed portion 33b of the stator 33 (described later), the inner circumferential surfaces of the first and second cylindrical bodies 36, 37, and the third cylindrical body 38, and the axially right end surface of the end plate 39.

[0056] The plunger 34 is arranged in the housing space 30 so as to be in sliding contact with the inner circumference of the third cylindrical body 38 processed to have low friction. There is a slight gap between the outer circumference of the plunger 34 and the inner circumference of the third cylindrical body 38, but fluid hardly passes through this gap.

[0057] That is, the housing space 30 is divided into a second space S2 formed on the axial right side of the plunger 34 and a third space S3 formed on the axial left side of the plunger 34 in a substantially sealed manner by disposing the plunger 34. The third space S3 is formed via a gap formed between the axial left end surface of the second cylindrical body 37 and the axial right end surface of the end plate 39 and a notch 31c of the solenoid housing 31 (see Figure 4 ) is connected to the outside of the solenoid valve 1.

[0058] like Figure 2 and Figure 3 As shown, the rod 35 is made of a non-magnetic material such as resin or rubber, and has a flange portion 35a extending outwardly at the axial left end portion. In addition, the rod 35 is fixed in a state where the end face of the flange portion 35a on the axial left side abuts the end face of the plunger 34 on the axial right side.

[0059] In addition, by energizing the coil 32a, an electromagnetic force is generated between the stator 33 and the plunger 34, so that when the plunger 34 and the rod 35 are moved axially to the right toward the stator 33, the axial right end face of the flange portion 35a of the rod 35 made of a non-magnetic material can abut the bottom surface of the recess 33b of the stator 33, thereby preventing the plunger 34 from sticking to the stator 33.

[0060] like Figure 2 、 Figure 3 and Figure 5As shown, the stator 33 is a cylindrical body having a through hole 33a extending axially through the center thereof, and is formed of a magnetic metal material such as iron. In addition, a recess 33b is formed at the axial left end portion of the stator 33, which is recessed axially rightward from the inner diameter side of the axial left end face of the base 33c (see FIG. Figure 2 、 Figure 3 ), the recess 33b is connected to the through hole 33a.

[0061] The stator 33 also has a small-diameter protrusion 33d that protrudes axially rightward from the inner diameter side of the axially right end surface of the base 33c. The protrusion 33d is embedded in the annular lower plate 32b and the recess 21e of the sleeve 21, which constitute the solenoid molded body 32. Furthermore, at the axially right end of the stator 33, an annular step 33e is formed by the outer circumferential surface of the protrusion 33d, the axially right end surface, and the outer circumferential surface of the base 33c.

[0062] When the protrusion 33d is inserted into the lower plate 32b and the recess 21e of the sleeve 21, the step 33e axially abuts against the axially left end surface of the lower plate 32b, thereby defining the insertion depth of the protrusion 33d into the recess 21e of the sleeve 21. Consequently, the end surface of the protrusion 33d, i.e., the axially right end surface of the stator 33, is axially separated from the bottom surface of the recess 21e of the sleeve 21. This forms an annular first space S1 axially opposite the second space S2 formed in the stator 33's axially left housing space 30, i.e., on the axial right side of the stator 33. Furthermore, the first space S1 is defined by the axially right end surface of the protrusion 33d, the inner circumferential surface and bottom surface of the recess 21e of the sleeve 21, and the outer circumferential surface of the spool 22. Thus, the axially left end portion of the spool 22 is accommodated within the first space S1.

[0063] The volume of the first space S1 changes according to the axial position of the spool 22. Specifically, in the closed state of the solenoid valve 1 (see Figure 2 ) under the condition that the step portion 22c of the slide column 22 abuts against the end face of the protrusion 33d of the stator 33, thereby forming the first space S1 only on the outer diameter side of the shoulder portion 22a, and its shape is annular, and its volume is minimized. In addition, when the slide column 22 is driven axially to the right by energizing the coil 32a, the step portion 22c separates axially to the right from the end face of the protrusion 33d of the stator 33. Therefore, in addition to the outer diameter side of the shoulder portion 22a, the first space S1 is also formed between the step portion 22c and the end face of the protrusion 33d of the stator 33, that is, on the outer diameter side of the protrusion 22b of the slide column 22 extending axially to the right from the through hole 33a of the stator 33, and its volume becomes larger (refer to Figure 3 ). In addition, Figure 3 Among them, the volume of the first space S1 is the largest.

[0064] like Figure 5As shown, an annular groove 33f is formed on the outer circumferential surface of the protruding portion 33d of the stator 33, recessed radially inward along the axially right end surface of the base portion 33c throughout the entire circumference. Furthermore, an axial groove 33g is formed on the outer circumferential surface of the protruding portion 33d of the stator 33, extending axially from the annular groove 33f to the approximately axial center of the protruding portion 33d. Furthermore, an axial groove 33h is formed in a portion of the circumference having a predetermined width, radially opposite to the axial groove 33g, i.e., 180 degrees opposite the radial center of the annular groove 33f, extending axially from the annular groove 33f to the end surface of the protruding portion 33d. The annular groove 33f, the axial groove 33g, and the axial groove 33h are formed so as to have substantially the same radial depth and width.

[0065] In addition, when the valve portion 2 is mounted on the solenoid portion 3, the axial groove 33g is arranged vertically below, and the axial groove 33h is arranged vertically above (see FIG. Figure 6 and Figure 7 ). In addition, the axial groove 33g has a tapered surface 33k that is inclined axially leftward from the outer diameter side toward the inner diameter side. When the valve portion 2 is mounted on the solenoid portion 3, the tapered surface 33k and the tapered surface 21k of the cutout 21h formed in the sleeve 21 are continuously arranged from the outer diameter side to the inner diameter side.

[0066] Furthermore, radial grooves 33 m extending radially inward from the axial grooves 33 h are formed on the end surface of the protruding portion 33 d of the stator 33 .

[0067] Next, the breathing path connecting the second space S2 in the storage space 30 and the outside of the solenoid valve 1 will be described. Since breathing between the third space S3 in the storage space 30 and the outside of the solenoid valve 1 is independently performed via the gap formed between the second cylindrical body 37 and the end plate 39 and the cutout 31c in the solenoid housing 31, a detailed description thereof will be omitted.

[0068] like Figure 6 and Figure 7 As shown, on the outer periphery of the protrusion 33d of the stator 33, an axial connecting path 102 extending in the axial direction is formed by the axial groove 33g and the inner peripheral surface of the lower plate 32b, an annular first breathing flow path 103 extending in the circumferential direction is formed by the annular groove 33f and the inner peripheral surface of the lower plate 32b, and a second breathing flow path 104 extending in the axial direction is formed by the axial groove 33h and the inner peripheral surface of the lower plate 32b and the recessed portion 21e of the sleeve 21.

[0069] The axially left end of the axial communication passage 102 is axially connected to the first breathing flow path 103, and the axially right end is radially connected to the breathing hole 101 formed by the cutout 21h of the sleeve 21 and the axially right end surface of the lower plate 32b. Furthermore, the breathing hole 101 communicates with the exterior of the solenoid valve 1 via the opening 31d of the solenoid housing 31. Furthermore, the breathing hole 101 forms a flow path that slopes outwardly toward the opening 31d of the solenoid housing 31, formed by the tapered surface 21k of the cutout 21h of the sleeve 21 and the inclined surface of the opening 32d of the solenoid molding 32 radially opposing the tapered surface 21k. This facilitates the flow of fluid between the breathing hole 101 and the opening 32d of the solenoid molding 32.

[0070] The axial left end of the second breathing flow path 104 is axially connected to the first breathing flow path 103, and the axial right end is axially connected to the first space S1. Furthermore, the axial right end of the second breathing flow path 104 is radially connected to the third breathing flow path 105 via a radial groove 33m extending radially inward on the end surface of the protrusion 33d of the stator 33. The third breathing flow path 105 is formed by the inner circumferential surface of the through hole 33a of the stator 33, the protrusion 22b of the spool 22, and the outer circumferential surface of the rod 35.

[0071] The axial left end of the third respiratory flow path 105 communicates with the second space S2 (see Figure 2 、 Figure 3 ), and the axial right end can be directly connected to the first space S1 according to the axial position of the sliding column 22.

[0072] Thus, in this embodiment, the breathing path connecting the second space S2 in the storage space 30 and the outside of the solenoid valve 1 is composed of the opening 31d of the solenoid shell 31, the breathing hole 101, the axial connecting path 102, the first breathing flow path 103, the second breathing flow path 104, the first space S1, the radial groove 33m, and the third breathing flow path 105 in sequence from the outside of the solenoid valve 1.

[0073] Next, the flow of the fluid in the breathing path accompanying the operation of the electromagnetic valve 1 will be described. Figure 6 As shown, when the solenoid valve 1 is switched from the closed state to the open state by energizing the coil 32a, thereby causing the plunger 34 to move axially to the right toward the stator 33, the fluid in the second space S2 is discharged from the inside of the solenoid valve 1 through the third breathing flow path 105, the radial groove 33m, the second breathing flow path 104, the first breathing flow path 103, the axial communication path 102, and the breathing hole 101 in sequence to the outside of the solenoid valve 1 (see Figure 6 solid arrow).

[0074] also, Figure 6The figure shows the state immediately after the coil 32a is energized, that is, the initial movement of the plunger 34. The fluid moving axially to the right by being pushed out from the second space S2 through the third breathing channel 105 collides with the axially left end face of the shoulder portion 22a of the slide column 22 and flows into the second breathing channel 104 through the radial groove 33m, and moves axially to the left in the second breathing channel 104, thereby generating a force that pushes the fluid in the first breathing channel 103 to the outside from the axial connecting channel 102 and the breathing hole 101 arranged vertically below.

[0075] In addition, if Figure 8 As shown in (a), the first breathing flow path 103 is formed in a ring shape. Therefore, when the solenoid valve 1 is in the closed state, the pollutants with heavier specific gravity in the fluid in the first breathing flow path 103 are easily gathered near the axial connecting path 102 formed vertically below, and are easily discharged to the outside together with the fluid through the axial connecting path 102 and the breathing hole 101.

[0076] In addition, if Figure 6 As shown, on the axial right side of the axial connecting path 102 and the breathing hole 101, the conical surface 33k of the axial groove 33g is connected to the conical surface 21k of the cutout 21h, guiding the flow of the fluid from the inner diameter side to the outer diameter side, thereby making it difficult to generate eddy currents in the axial connecting path 102 and the breathing hole 101, and pollutants are easily discharged to the outside together with the fluid.

[0077] Furthermore, the breathing hole 101 forms a flow path inclined toward the outer diameter side of the opening 31d formed in the solenoid case 31 by the tapered surface 21k of the cutout 21h of the sleeve 21 and the inclined surface of the opening 32d of the solenoid molded body 32, so that pollutants are easily discharged to the outside together with the fluid.

[0078] Furthermore, when the spool 22 is driven axially rightward by the movement of the plunger 34 and rod 35, the axially left end surface of the shoulder portion 22a of the spool 22 separates axially rightward from the end surface of the protrusion 33d of the stator 33. Consequently, fluid moving axially rightward in the third breathing flow path 105 flows directly into the first space S1. At this time, the radial grooves 33m open toward the first space S1, and the fluid moving axially rightward, pushed out of the second space S2 through the third breathing flow path 105, flows out into the increased volume of the first space S1. Consequently, the force exerted by the fluid on the spool 22 to the right does not become excessive.

[0079] Furthermore, the annular first breathing flow path 103 and the axially extending second breathing flow path 104 can form a longer breathing path, thereby preventing the fluid in the breathing path from being excessively discharged to the outside of the solenoid valve 1 .

[0080] On the other hand, Figure 7As shown, for example, when the solenoid valve 1 is switched from the open state to the closed state by cutting off the power to the coil 32a, thereby moving the plunger 34 axially to the left, the fluid existing outside the solenoid valve 1 is supplied from the outside of the solenoid valve 1 to the second space S2 through the breathing hole 101, the axial communication path 102, the first breathing flow path 103, the second breathing flow path 104, the radial groove 33m, the first space S1 and the third breathing flow path 105 in sequence (see Figure 7 solid arrow).

[0081] also, Figure 7 Immediately after deenergizing coil 32a, i.e., during the initial movement of plunger 34, fluid, flowing axially rightward from the outside of solenoid valve 1 through breathing hole 101 and axial communication passage 102 into first breathing passage 103 and then being pushed out from first breathing passage 103 through second breathing passage 104, primarily flows outward from a position radially outward of spool 22 into first space S1, which has a larger volume. This prevents the fluid from directly colliding with spool 22 and instead disperses within first space S1, thereby reducing its flow. This reduces the radial impact of the fluid, prevents spool 22 from tilting, and maintains coaxiality with sleeve 21. This maintains smooth sliding of spool 22 relative to sleeve 21, improving the responsiveness of solenoid valve 1.

[0082] In addition, if Figure 8 As shown in (b), the first breathing flow path 103 is formed into an annular shape. Even if contaminants in the fluid outside the solenoid valve 1 enter the first breathing flow path 103 through the breathing hole 101 formed vertically below and the axial communication path 102, they are required to move approximately 180 degrees circumferentially within the first breathing flow path 103 along with the fluid to flow into the second breathing flow path 104, which is arranged vertically above and radially opposite the axial communication path 102. As a result, contaminants with a heavier specific gravity in the fluid tend to fall to the lower side of the first breathing flow path 103, making it difficult for contaminants to enter the second breathing flow path 104. Furthermore, since the fluid in the first space S1 is primarily supplied to the second space S2 via the third breathing flow path 105, contaminants are also unlikely to enter the second space S2.

[0083] Furthermore, by arranging the breathing hole 101 and the axial communication path 102 vertically downward, even when the solenoid valve 1 is placed in a semi-oil environment, for example, the fluid existing outside the solenoid valve 1 can be easily sucked in.

[0084] Furthermore, the annular first breathing flow path 103 and the axially extending second breathing flow path 104 can form a long breathing path, so that contaminants existing outside the solenoid valve 1 are less likely to enter the second space S2 .

[0085] In addition, if Figure 7As shown, the second breathing flow path 104 is connected to the first space S1 on the outer diameter side of the slide 22. Therefore, especially after the power to the coil 32a is just cut off, that is, in the initial movement of the plunger 34, the fluid that moves axially to the right in the second breathing flow path 104 and flows out into the first space S1 mainly acts on the sleeve 21 on the outer diameter side of the slide 22, and is unlikely to affect the movement of the slide 22.

[0086] In addition, a radial groove 33m is formed on the end face of the protrusion 33d of the stator 33, which opens to the first space S1 and connects the second breathing flow path 104 and the third breathing flow path 105. Regardless of the axial position of the sliding column 22, the second breathing flow path 104 and the third breathing flow path 105 are always connected, so that the movement of the fluid in the breathing path is not hindered, and the resistance generated by the fluid accompanying the movement of the plunger 34 can be reliably reduced.

[0087] As described above, the solenoid valve 1 of the present embodiment not only has stable damping performance through the breathing path but also can exhibit high responsiveness and contaminant resistance.

[0088] In addition, the axial connecting path 102, the first breathing flow path 103, and the second breathing flow path 104 that constitute the breathing path are formed by the annular groove 33f, the axial groove 33g, and the axial groove 33h arranged on the outer peripheral surface of the stator 33. Therefore, by processing each groove on the outer peripheral surface of the stator 33, a part of the breathing path can be easily formed on the outer periphery of the stator 33.

[0089] While the embodiments of the present invention have been described above with reference to the drawings, the specific configuration is not limited to these embodiments, and any changes or additions that do not depart from the gist of the present invention are also encompassed by the present invention.

[0090] For example, in the above embodiment, the first space S1 constituting the breathing path is described as being divided by the end surface on the axial right side of the protrusion 33d of the stator 33, the inner peripheral surface and the bottom surface of the recess 21e of the sleeve 21, and the outer peripheral surface of the slide column 22. However, this is not limited to this. As long as the first space S1 is formed on the axially opposite side of the storage space formed on the axial left side of the stator, that is, on the axial right side of the stator, it can also be divided by other components such as a rod.

[0091] In addition, in the above embodiment, the case where the annular groove 33f, the axial groove 33g, and the axial groove 33h provided on the outer peripheral surface of the stator 33 form the axial connecting path 102, the first breathing flow path 103, and the second breathing flow path 104 constituting the breathing path is described, but it is not limited to this. For example, grooves may be formed on the inner peripheral surface of the lower plate and the inner peripheral surface of the recessed portion of the sleeve, and a breathing path may be constituted together with the outer peripheral surface of the protruding portion of the stator.

[0092] In the above embodiment, the first breathing flow path 103 is described as being annular, but the present invention is not limited thereto. As long as the first breathing flow path extends circumferentially on the outer periphery of the stator, it may be formed into a closed shape.

[0093] In addition, in the above embodiment, the case where the first breathing flow path 103 is connected to the outside of the solenoid valve 1 via the axial connecting path 102 extending axially toward the opening 31d of the solenoid housing 31 is described, but it is not limited to this. It is also possible that no axial connecting path is provided, and the first breathing flow path is connected to the outside via the breathing hole and the opening of the solenoid housing.

[0094] In addition, in the above embodiment, the breathing hole 101 is described as being formed by the cutout 21h of the sleeve 21 and the axially right end surface of the lower plate 32b, but this is not limited to this. For example, the breathing hole may be formed by a through hole that penetrates the sleeve in the radial direction.

[0095] In addition, in the above embodiment, the second breathing flow path 104 is described as being connected to the first space S1 on the outer diameter side of the shoulder portion 22a of the slide column 22, but this is not limited to this. It can also be formed so that the axial right end of the second breathing flow path and the axial left end face of the shoulder portion of the slide column are axially opposite.

[0096] Furthermore, in the above embodiment, the second breathing flow path 104 and the axial communication path 102 are described as being radially opposed to each other. However, this is not limiting. For example, the second breathing flow path and the axial communication path may be formed with a 90-degree phase shift in the circumferential direction. Furthermore, from the perspective of contaminant resistance, it is preferred that the second breathing flow path and the axial communication path be circumferentially shifted in phase by 90 degrees or more.

[0097] The axial communication path 102 may not be formed vertically below the outer periphery of the stator 33. From the viewpoints of contaminant resistance and fluid inhalation, the axial communication path is preferably formed to communicate with the lower side of the first respiratory flow path.

[0098] Furthermore, in the above embodiment, the radial grooves 33m are formed on the end surface of the protrusion 33d of the stator 33. However, the present invention is not limited to this. The radial grooves may be formed on the end surface of the shoulder portion of the slide post axially opposed to the end surface of the protrusion 33d of the stator 33. Furthermore, the radial grooves may not be formed on the stator or the slide post.

[0099] In addition, in the above embodiment, the breathing hole 101 constituting the breathing path is described as being formed on the axial left side of the opening 31d of the solenoid housing 31, that is, inside the solenoid housing 31. However, this is not limited to this. The breathing hole can also be formed outside the solenoid housing. In addition, the fluid can also flow directly into or out of the breathing path through the opening formed on the sleeve, that is, the breathing hole.

[0100] Furthermore, in the above embodiment, the rod 35 and the spool 22 are described as being separate bodies. However, the present invention is not limited thereto, and the rod and the spool may be formed integrally.

[0101] Explanation of symbols

[0102] 1: Solenoid valve; 2: Valve unit; 3: Solenoid unit; 21: Sleeve; 21a: Through hole; 21e: Recess; 21h: Cutout (opening); 21k: Tapered surface; 22: Slider; 22a: Shoulder; 22b: Protrusion; 30: Storage space; 31: Solenoid housing; 31d: Opening; 32: Solenoid molded body; 32b: Lower plate; 33: Stator; 33a: Through hole; 33b: Recess; 33c: Base; 33d: Protrusion; 33e: Step; 33f: Annular groove ; 33g: axial groove; 33h: axial groove; 33k: conical surface; 33m: radial groove; 34: plunger; 35: rod; 35a: flange portion; 36: first cylindrical body; 37: second cylindrical body; 38: third cylindrical body; 39: end plate; 101: breathing hole; 102: axial connecting path; 103: first breathing flow path; 104: second breathing flow path; 105: third breathing flow path; S1: first space; S2: second space (storage space); S3: third space (storage space).

Claims

1. A solenoid valve comprising: The valve portion includes a sleeve that accommodates a spool in an axially movable manner; and a solenoid portion includes a plunger that contacts or separates from a stator by electromagnetic force and drives the spool in the axial direction, a solenoid molded body arranged on the outer periphery of the plunger and the stator, and a solenoid housing that accommodates the solenoid molded body. The plunger is arranged inside the solenoid portion in a housing space at least partially partitioned by the stator. The solenoid valve comprises: a first breathing flow path extending at least in a circumferential direction on the outer periphery of the stator and communicating with the outside of the solenoid valve; a second breathing flow path extending axially from the first breathing flow path over a portion of the circumference thereof and communicating with a first space formed between the stator, the sleeve, and the slide post; as well as a third breathing flow path extending axially on the inner periphery of the stator and connecting the first space with the storage space; The first breathing flow path is formed in an annular shape and communicates with the outside of the solenoid valve through an axial communication path extending in the axial direction toward an opening formed in the solenoid housing; In the direction of fluid flow, the second respiratory flow path is located between the first respiratory flow path and the third respiratory flow path.

2. The solenoid valve according to claim 1, wherein: The second breathing flow path communicates with the first space on the outer diameter side of the spool.

3. The solenoid valve according to claim 1 or 2, wherein: The second breathing flow path and the axial communication path are radially opposed to each other.

4. The solenoid valve according to claim 1, wherein: The axial communication path is formed vertically below the outer circumference of the stator.

5. The solenoid valve according to claim 1, wherein A radial groove is formed on the stator or the slide post to connect the second breathing flow path with the third breathing flow path.

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