JP4672610B2 - Solenoid valve and manufacturing method thereof - Google Patents

Description

  The present invention relates to an electromagnetic valve capable of displacing a valve body by attracting a movable core to a fixed core by an electromagnetic force generated under the excitation action of a solenoid, and a manufacturing method thereof.

  2. Description of the Related Art Conventionally, an electromagnetic valve that displaces a valve body by attracting a movable iron core to a fixed iron core by an electromagnetic force generated under the excitation action of a solenoid coil has been used.

  For example, such a solenoid valve is provided inside the case and excites a coil wound around the bobbin so that the plunger provided inside the bobbin is displaced along the axial direction by the electromagnetic force. Then, the spherical valve element is pressed against the valve seat of the supply port via the shaft connected to the plunger. As a result, the supply port is closed by the valve element under the pressing action by the shaft, and communication between the supply port through which the fluid flows and the discharge port is blocked (see, for example, Patent Document 1).

Japanese Utility Model Publication No. 63-49074

  By the way, in the prior art which concerns on patent document 1, since the end part of a shaft is always in contact with the spherical surface of a spherical valve element, for example, the electromagnetic force generated by the coil is increased, and the valve element is When increasing the sealing force when abutting against the seat, the sliding resistance generated between the end of the shaft and the contact surface of the valve increases, so that the end of the shaft becomes worn and durable. There is a problem that the performance is lowered.

  The present invention has been made in view of the above problems, and provides a solenoid valve capable of reducing the wear of the shaft and improving its durability by subjecting the shaft to a surface treatment, and a method for manufacturing the same. The purpose is to do.

In order to achieve the above object, the present invention provides a solenoid valve body including a valve body having a first port and a second port through which a pressure fluid flows, and a housing;
A coil disposed inside the housing and wound around a coil bobbin; a yoke connected to one end of the housing; a movable core sucked by a fixed core portion under an energizing action on the coil; and the fixed core A solenoid part having a spring member interposed between the part and the movable core and returning the movable core to an initial position;
A valve mechanism having a shaft coupled to the movable core and displaced integrally with the movable core; and a valve body that opens and closes a communication path between the first port and the second port under the displacement action of the shaft;
With
The shaft is formed of a metal material, and a first coating layer having a predetermined thickness is formed on the outer surface of the shaft by ion nitriding treatment, and the thickness of the first coating layer is increased by thermal diffusion treatment. It is characterized by doing.

  According to the present invention, by performing an ion nitriding treatment on the shaft that is displaced integrally with the movable core, the hardness of the shaft is higher than the hardness of the valve body pressed against the end of the shaft, A first coating layer having a predetermined thickness is formed on the outer surface of the shaft. Thereafter, in order to reduce the hardness of the shaft to a value substantially equal to or lower than the hardness of the valve body, heat diffusion treatment is performed, and the hardness of the shaft is set slightly lower than the hardness of the valve body by the heat diffusion treatment.

  Therefore, by increasing the hardness of the shaft, it is possible to reduce wear caused when the shaft and the valve body come into contact with each other. Also, a first coating layer having a predetermined thickness is formed on the outer surface of the shaft by ion nitriding, and the thickness of the first coating layer is increased by the thermal diffusion treatment, so that the coating layer is coated on the shaft. Can be made thicker than when only ion nitriding is performed.

  As a result, the hardness of the shaft that comes into contact with the valve body is set appropriately, wear is reduced, and the toughness is obtained by the first coating layer having an increased thickness. And the durability of the shaft can be improved, the flow rate of the pressure fluid can be controlled with high accuracy by the valve body that is opened and closed via the shaft, and the flow rate can be controlled stably over a long period of time. .

  Moreover, it is good to form the valve body support part which faces the seat part which a valve body seats to a valve body, and supports this valve body so that a displacement is possible along an axial direction. Accordingly, when the valve body is separated from the seating portion, or when the valve body separated from the seating portion is seated again on the seating portion, the valve body is reliably secured along the axial direction by the valve body support portion. And it can be displaced suitably. As a result, the valve body can be smoothly switched between the valve open state and the valve closed state, and the valve body is not displaced in a direction substantially perpendicular to the axis, so that the shaft abuts against the valve body. The position becomes constant, and stable valve opening and closing operations can be performed by the shaft and the valve body.

  Further, by providing the valve body with a guide member that supports the shaft so as to be displaceable along the axial direction, the shaft can be displaced with high accuracy along the axial direction, and the guide member is provided with the valve. Since it is provided inside the body, the shaft can be guided at a position close to the valve body. As a result, the end of the shaft can always be brought into contact with the valve body at a stable position as compared with a conventional electromagnetic valve that does not have a mechanism for guiding the shaft.

  Furthermore, the hardness of the shaft may be set higher than the hardness of the valve body by performing ion nitriding treatment, and may be set lower than the hardness of the valve body by performing thermal diffusion treatment. As a result, the hardness of the shaft can be increased by ion nitriding treatment, and the hardness can be reduced by performing thermal diffusion treatment after the ion nitriding treatment. That is, the shaft hardness can be set to an appropriate value according to the hardness of the valve body.

Still further, the present invention provides a solenoid valve main body including a valve body having a first port and a second port through which a pressure fluid flows, and a housing;
A coil disposed inside the housing and wound around a coil bobbin; a yoke connected to one end of the housing; a movable core sucked by a fixed core portion under an energizing action on the coil; and the fixed core A solenoid part having a spring member interposed between the part and the movable core and returning the movable core to an initial position;
A valve mechanism having a shaft coupled to the movable core and displaced integrally with the movable core; and a valve body that opens and closes a communication path between the first port and the second port under the displacement action of the shaft;
With
The shaft is formed of a metal material, and a first coating layer having a predetermined thickness is formed on the outer surface of the shaft by ion nitriding treatment, and the thickness of the first coating layer is increased by thermal diffusion treatment. In addition, a second coating layer is formed.

  According to the present invention, by performing an ion nitriding treatment on the shaft that is displaced integrally with the movable core, the hardness of the shaft is higher than the hardness of the valve body pressed against the end of the shaft, A first coating layer having a predetermined thickness is formed on the outer surface of the shaft. Thereafter, in order to reduce the hardness of the shaft to a value substantially equal to or lower than the hardness of the valve body, a thermal diffusion treatment is performed to increase the thickness of the first coating layer and to form a second coating layer. .

  Therefore, by increasing the hardness of the shaft, it is possible to reduce wear caused when the shaft and the valve body come into contact with each other. Also, a first coating layer having a predetermined thickness is formed on the outer surface of the shaft by ion nitriding, and the thickness of the first coating layer is increased by the thermal diffusion treatment, so that the coating layer is coated on the shaft. Can be made thicker than when only ion nitriding is performed.

  As a result, the hardness of the shaft that comes into contact with the valve body is set appropriately, wear is reduced, and the toughness is obtained by the first coating layer having an increased thickness. And the durability of the shaft can be improved, the flow rate of the pressure fluid can be controlled with high accuracy by the valve body that is opened and closed via the shaft, and the flow rate can be controlled stably over a long period of time. .

  Further, the second coating layer formed by the thermal diffusion treatment has a lower hardness than the first coating layer, and a higher hardness than the base material of the shaft. That is, the second coating layer has a relaxation function capable of relaxing the hardness difference between the first coating layer and the shaft base material. Furthermore, since the thickness of the second coating layer is added to the shaft in addition to the thickness of the first coating layer, the impact when the shaft comes into contact with the valve body is suitably absorbed. In other words, it is possible to improve the shock absorption of the shaft. As a result, the durability of the shaft can be further improved.

Furthermore, the present invention provides a solenoid valve body including a valve body having a first port and a second port through which a pressure fluid flows, and a housing;
A coil disposed inside the housing and wound around a coil bobbin; a yoke connected to one end of the housing; a movable core sucked by a fixed core portion under an energizing action on the coil; and the fixed core A solenoid part having a spring member interposed between the part and the movable core and returning the movable core to an initial position;
A valve mechanism having a shaft coupled to the movable core and integrally displaced with the movable core; and a valve body that opens and closes a communication path between the first port and the second port under the displacement action of the shaft. In the method of manufacturing a solenoid valve,
Applying ion nitriding to the outer surface of the shaft;
Applying heat diffusion treatment to the outer surface of the shaft;
It is characterized by having.

  According to the present invention, by performing ion nitriding treatment on the shaft, the hardness of the shaft is made higher than the hardness of the valve body pressed against the end of the shaft, and the outer surface of the shaft has a predetermined thickness. A first coating layer is formed. Next, the shaft subjected to the ion nitriding treatment is subjected to a thermal diffusion treatment, so that the hardness of the shaft is lowered and set to be substantially equal to or lower than the hardness of the valve body.

  Therefore, by increasing the hardness of the shaft, it is possible to reduce wear caused when the shaft and the valve body come into contact with each other, and to increase the thickness of the first coating layer coated on the outer surface of the shaft. can do.

  As a result, the hardness of the shaft that comes into contact with the valve body is set appropriately, wear is reduced, and the toughness is obtained by the first coating layer having an increased thickness. And the durability of the shaft can be improved, the flow rate of the pressure fluid can be controlled with high accuracy by the valve body that is opened and closed via the shaft, and the flow rate can be controlled stably over a long period of time. .

  According to the present invention, the following effects can be obtained.

  That is, an ion nitriding treatment is applied to the shaft that is displaced integrally with the movable core to increase the hardness, and a first coating layer having a predetermined thickness is formed on the outer surface. Diffusion treatment is performed so that the shaft has a hardness substantially equal to that of the valve body. As a result, the hardness of the shaft is made substantially equal to that of the valve body to reduce wear caused when the shaft and the valve body come into contact with each other, and when the first coating layer having increased thickness contacts the valve body. Therefore, the durability of the shaft can be improved.

  A preferred embodiment of the electromagnetic valve according to the present invention will be described in detail with reference to the accompanying drawings.

  In FIG. 1, reference numeral 10 indicates a solenoid valve to which a method for manufacturing a solenoid valve according to an embodiment of the present invention is applied.

  The electromagnetic valve 10 includes a housing 14 in which a solenoid portion 12 is provided, and a valve body 18 that is integrally connected to the housing 14 and in which a valve mechanism portion 16 is provided. The housing 14 may be formed of a magnetic material such as SUM (JIS standard), for example, and the valve body 18 may be formed of a nonmagnetic material such as aluminum.

  The valve body 18 has a substantially cylindrical shape, and a supply port (first port) 20 to which a high-pressure fluid is supplied is formed at the lower end of the valve body 18. A discharge port (second port) 22 communicating with the supply port 20 through the communication path 24 is formed.

  The communication passage 24 functions as a valve body that blocks the communication passage 24 by sitting on a seat portion 26 formed on the inner wall of the valve body 18 and opens the communication passage 24 by separating from the seat portion 26. A ball 28 is provided. The ball 28 is formed of bearing steel such as SUJ (JIS standard), for example, and has a surface hardness set in a range of Hmv 800 to 900. When the coil 30 (described later) of the solenoid portion 12 is in a non-energized state, the ball 28 is seated on the seat portion 26 via a shaft 36 pressed by the elastic force of a return spring 32 described later. Closed.

  Inside the valve body 18, a ball guide (valve support portion) 34 extending in the axial direction from the seating portion 26 toward the housing 14 is formed, and the ball guide 34 is substantially the same as the outer diameter of the ball 28. It is formed with a diameter.

  Further, a space 38 is formed inside the valve body 18 so as to face the ball guide 34, and a shaft 36 that can be displaced along the axial direction is disposed in the space 38. One end 36 a of the shaft 36 abuts on the spherical surface of the ball 28, and the other end is connected to a movable core 40 described later. One end 36a of the shaft 36 is formed in a planar shape (see FIG. 3). The shaft 36 may be integrated with the movable core 40 by caulking molding or the like.

  The shaft 36 is made of, for example, a nonmagnetic material such as SUS304 (JIS standard), and is subjected to ion nitriding treatment (for example, 600 ° C. for 6 hours) for the purpose of increasing the surface hardness. By processing, the first coating layer 42 is formed with a predetermined thickness on the entire surface of the shaft 36 (see FIG. 3A). Specifically, the surface hardness is increased to Hmv 1150 by the ion nitriding treatment, and the thickness t1 of the first coating layer 42 is formed to be about 62 μm, for example. Thereby, the surface hardness of about 5 times can be obtained compared with the state of the nonmagnetic material before the ion nitriding treatment.

  However, since the surface hardness of the shaft 36 that has been subjected to the ion nitriding treatment becomes higher than the surface hardness (Hmv 800 to 900) of the ball 28, the ball 28 is in contact with the ball 28 when the ball 28 comes into contact with the shaft 28. Wear will occur on the side. Therefore, in order to make the surface hardness of the shaft 36 approximately equal to the surface hardness of the ball 28, the shaft 36 that has been subjected to the ion nitriding treatment is subjected to a thermal diffusion treatment (for example, at 700 ° C. for 2 hours). The surface hardness of is intentionally reduced. By performing this thermal diffusion treatment, the surface hardness of the shaft 36 can be lowered to Hmv650, and can be set slightly lower than the surface hardness (Hmv 800 to 900) of the ball 28.

  In other words, the surface hardness of the shaft 36 can be approximately tripled compared to the state of the nonmagnetic material before the ion nitriding treatment.

  At this time, as shown in FIG. 3A, the thickness of the first coating layer 42 is increased by further performing thermal diffusion processing on the shaft 36 on which the first coating layer 42 is formed by ion nitriding ( (See t1 ′ in FIG. 3B). Specifically, by applying a heat diffusion treatment, the thickness of the first coating layer 42 formed on the surface of the shaft 36 is increased, and from the inner peripheral side of the first coating layer 42 to the inside of the shaft 36. A second coating layer 44 is formed so as to penetrate. That is, the outer surface of the shaft 36 is covered with two layers including the first and second coating layers 42 and 44. In this case, as shown in FIG. 3B, the thickness t1 of the first coating layer 42 is further increased by the thermal diffusion treatment (t1 ′ in FIG. 3B), and the thickness t2 of the second coating layer 44 is It is formed thinner than the first coating layer 42 (t1 ′ <t2). For example, the thickness t2 of the second coating layer 44 is formed to be about 1/10 of the thickness t1 ′ of the first coating layer 42.

  Thereby, the thickness of the first coating layer 42 coated on the outer surface of the shaft 36 becomes thicker than that in the case of only the ion nitriding treatment, for example, about 100 μm.

  The thickness of the second coating layer 44 is, for example, about 10 μm, and the thickness obtained by adding the second coating layer 44 to the first coating layer 42 is about 110 μm.

  Furthermore, the hardness of the second coating layer 44 is set lower than the hardness of the first coating layer 42 and higher than the hardness of the base material in the shaft 36. That is, the second coating layer 44 has a relaxation function that can alleviate the hardness difference between the base material of the shaft 36 and the first coating layer 42. Further, since the thickness of the second coating layer 44 is added to the shaft 36 in addition to the thickness of the first coating layer 42, the impact when the shaft 36 contacts the ball 28 is suitably absorbed. . In other words, it is possible to improve the shock absorption of the shaft 36 by forming the second coating layer 44. As a result, the durability of the shaft 36 can be further improved.

  The shaft 36 is held so as to be displaceable along the axial direction by being inserted through a guide hole 48 of a guide member 46 provided in the space 38. Therefore, the displacement of the shaft 36 in the radial direction is restricted by the guide hole 48 and is preferably guided along the axial direction. The guide member 46 is made of a metal material such as brass, for example. The guide member 46 is disposed in the space 38 of the valve body 18, but only the guide hole 48 for guiding the shaft 36 may be integrally formed in the valve body 18.

  On the other hand, a seal member 50 is provided on the outer peripheral surface of the valve body 18 so as to be spaced apart by a predetermined distance along the axial direction and mounted in an annular groove.

  The solenoid portion 12 includes a housing 14 having a fixed core portion 52 protruding by a predetermined length along the axial direction of the shaft 36, a coil 30 housed in the housing 14 and wound around a coil bobbin 54, and a substantially cylindrical shape. And a movable core 40 having a stepped hole portion 56 formed in the center and penetrating along the axial direction.

  The fixed core portion 52 is formed integrally with the housing 14 by forging, for example.

  The movable core 40 is formed with a passage 58 that is perpendicular to the axial direction and communicates with a stepped hole portion 56 at the center. The passage 58 fills a clearance 60 between the fixed core portion 52 and the movable core 40. Has a function of releasing the pressurized fluid. The coil bobbin 54 is made of a resin material, for example.

  The solenoid portion 12 has a return spring (spring member) having one end portion engaged with the inner wall surface of the fixed core portion 52 and the other end portion engaged with the step portion of the stepped hole portion 56 of the movable core 40. ) 32 and a yoke 62 connected to one end of the housing 14 and surrounding the outer peripheral surface of the movable core 40. When the movable core 40 is pressed in the direction away from the fixed core portion 52 (in the direction of arrow A) by the elastic force of the return spring 32, the coil 30 of the solenoid portion 12 is in an off state in which no current is supplied. A predetermined clearance 60 is formed between the movable core 40 and the fixed core portion 52 (see FIG. 1).

  The movable core 40 is formed of a substantially cylindrical body, and the diameter of the outer peripheral surface of the end facing the fixed core portion 52 is gradually increased as compared with other portions of the movable core 40 and substantially the same as the fixed core portion 52. It has an enlarged diameter portion 66 having the same diameter.

  In this case, even though the yoke 62 is interposed between the coil bobbin 54 and the movable core 40 by forming the enlarged core portion 66 having substantially the same diameter as the fixed core portion 52 with respect to the movable core 40. Accordingly, the area of the movable core 40 facing the fixed core portion 52 can be increased, and the magnetic characteristics can be improved.

  The yoke 62 surrounds the outer peripheral surface of the movable core 40 and extends along the axial direction (arrow A, B direction), and protrudes radially outward from the outer peripheral surface of the cylindrical portion 68. The lower end portion of the cylindrical portion 68 is fitted to the spigot portion 72 that is formed of the annular flange portion 70 and formed on the inner wall of the valve body 18.

  Further, by fitting the yoke 62 to the inlay portion 72, it is possible to satisfactorily maintain the assembling property of the yoke 62 with respect to the valve body 18 and to improve the assembling accuracy. The yoke 62 is integrally formed of a magnetic material such as SUM (JIS standard), for example.

  Further, the cylindrical portion 68 of the yoke 62 is formed so that the end surface along the axial direction extends to the vicinity of the enlarged diameter portion 66 of the movable core 40 when the solenoid portion 12 is in the OFF state.

  Thus, since the length of the section in which the magnetic gap between the yoke 62 and the movable core 40 acts can be kept constant regardless of the on / off operation of the solenoid unit 12, the solenoid unit 12 can be turned on / off. It is possible to prevent the suction force (electromagnetic force) from being affected by the off operation.

  Between the housing 14 and the coil 30, there is provided a resin sealing body 74 for molding a part of the outer peripheral surface of the coil 30 and the coil bobbin 54. The resin sealing body 74 is continuous with a coupler section 76 described later. Are integrally formed of a resin material.

  Also, between the resin sealing body 74 adjacent to the coil bobbin 54 and the housing 14, and between the upper surface of the annular flange portion 70 of the yoke 62 and the resin sealing body 74, the same triangular cross section is the same. O-rings 78a and 78b having a shape are mounted. Further, an O-ring 80 is also mounted between the lower surface of the annular flange portion 70 of the yoke 62 and the valve body 18.

  In this case, annular inclined surfaces for arranging the O-rings 78a and 78b having a triangular cross section are arranged symmetrically at the center of the upper and lower end surfaces along the axial direction of the resin sealing body 74. Accordingly, it is possible to use the same O-rings 78a and 78b, and it is possible to reduce the manufacturing cost and prevent erroneous assembly.

  The end portion of the housing 14 is pressurized by a crimping means (not shown), and is crimped to the upper portion of the valve body 18 so as to be integrally connected.

  Further, a coupler portion 76 for energizing the coil 30 is provided on the side portion of the housing 14, so that the terminal portion 82 a of the terminal 82 electrically connected to the coil 30 is exposed to the coupler portion 76. Provided.

  The electromagnetic valve 10 according to the embodiment of the present invention is basically configured as described above. Next, the operation and effects thereof will be described. When the coil 30 of the solenoid unit 12 is not energized, as shown in FIG. 1, the valve 28 is closed with the ball 28 seated on the seating portion 26, and the communication between the supply port 20 and the discharge port 22 is established. It is in a blocked state.

  In such a valve closed state, a power source (not shown) is energized and the coil 30 is energized, whereby the solenoid unit 12 is excited and turned on, and sequentially passes through the housing 14, the yoke 62, the movable core 40, and the fixed core unit 52. Thus, a magnetic flux returning to the housing 14 is generated.

  Then, the movable core 40 is attracted to the fixed core portion 52 by overcoming the pressing force of the return spring 32 by the electromagnetic force generated by the solenoid portion 12. Then, the shaft 36 integrally connected to the movable core 40 is displaced upward (in the direction of arrow B) under the guide action of the cylindrical portion 68 of the yoke 62, and accordingly, the shaft 36 is guided by the guide member 46. The one end 36 a of the shaft 36 is separated from the ball 28 by being displaced downward and upward.

  Accordingly, the pressing force that urges the ball 28 toward the seating portion 26 disappears, and the ball 28 is separated from the seating portion 26 by the pressing force of the pressure fluid introduced from the supply port 20, so that the supply port 20 and the discharge port 22 are separated. The opened valve is in communication (see FIG. 2). Then, the pressure fluid (for example, pressure oil) introduced from the supply port 20 is led to an external fluid device (not shown) via the discharge port 22.

  On the other hand, when the energization to the coil 30 of the solenoid unit 12 is stopped, the electromagnetic force disappears, and the movable core 40 and the shaft 36 are displaced downward under the action of the elastic force of the return spring 32, and the ball 28 is pressed to return to the valve-closed state where the ball 28 is seated on the seat portion 26.

The pressure fluid flowing through the valve body 18 of the electromagnetic valve 10 is not particularly limited as long as it is a liquid such as water, fuel, pressure oil, and the pressure is, for example, 20 to 30 kgf / cm ² . It is good to set.

  In the above description, a high-pressure electromagnetic two-way valve having a pair of supply port 20 and discharge port 22 has been described. However, this configuration may be applied to a three-way valve or the like, or a low-pressure pressure may be applied. You may make it use when controlling the distribution | circulation of the fluid.

  As described above, in the present embodiment, the surface hardness of the shaft 36 is set to one end portion 36 a of the shaft 36 by performing ion nitriding treatment on the shaft 36 that is displaceable integrally with the movable core 40. The first coating layer 42 having a predetermined thickness is formed on the outer surface of the shaft 36. After that, by applying a heat diffusion treatment to reduce the surface hardness of the shaft 36 to a value substantially equal to the surface hardness of the ball 28, the surface hardness of the shaft 36 is reduced by the heat diffusion treatment. Since it can be set slightly lower than the surface hardness, it is possible to reduce wear caused when the one end portion 36a of the shaft 36 and the spherical surface of the ball 28 come into contact with each other.

  Further, since the first coating layer 42 formed by ion nitriding treatment is formed on the outer surface of the shaft 36 to become the first coating layer 42 having an increased thickness by the thermal diffusion treatment, the coating layer coated on the shaft 36. Can be made thicker than when only ion nitriding is performed.

  As described above, by performing the thermal diffusion treatment after the ion nitriding treatment, the surface hardness becomes slightly lower than the surface hardness of the ball 28, and the shaft 36 having the thick first coating layer 42 coated on the outer surface is obtained. can get. As a result, the surface hardness of the one end portion 36a of the shaft 36 that comes into contact with the ball 28 is set appropriately, and the toughness is obtained by the first coating layer 42, so that an appropriate shock absorption property is obtained. Durability can be significantly improved.

  As a result, the wear of the one end portion 36a of the shaft 36 can be prevented, so that highly accurate flow control of the pressure fluid by the ball 28 opened and closed via the shaft 36 is possible, and stable flow control can be performed over a long period of time. It can be carried out.

  In addition, a ball guide 34 is formed at a position facing the communication passage 24 of the valve body 18 and is formed with substantially the same diameter along the axial direction and in which the balls 28 are disposed. The inner peripheral diameter of the ball guide 34 is formed to be approximately the same as or slightly larger than the diameter of the ball 28.

  Accordingly, when the ball 28 is displaced upward from the seating portion 26 or when the ball 28 separated from the seating portion 26 is seated on the seating portion 26 again, the ball 28 is moved in the axial direction. It is possible to reliably and suitably displace it along. Thereby, the switching between the valve open state and the valve closed state by the ball 28 can be performed smoothly, and since the radial displacement does not occur, the contact position of the shaft 36 with respect to the ball 28 is always constant, and the shaft Stable valve opening and closing operations can be performed by the ball 36 and the ball 28.

  Furthermore, the surface hardness of the shaft 36 can be increased by ion nitriding treatment, and the surface hardness can be lowered by performing thermal diffusion treatment after the ion nitriding treatment. In this way, the surface hardness of the outer surface of the shaft 36 can be set to an appropriate value according to the surface hardness of the ball 28 (specifically, a value slightly smaller than the surface hardness of the ball 28). It is.

  Furthermore, by providing the guide member 46 in which the shaft 36 is guided along the axial direction, the shaft 36 can be displaced with high precision along the axial direction, and the guide member 46 is provided in the valve body. 18, the shaft 36 can be guided at a position close to the ball 28 that functions as a valve body. Therefore, as compared with a conventional electromagnetic valve that does not have a mechanism for guiding the shaft 36, the one end portion 36 a of the shaft 36 can always be brought into contact with the surface of the ball 28 at a stable position.

It is a longitudinal cross-sectional view along the axial direction of the solenoid valve to which the manufacturing method of the solenoid valve concerning embodiment of this invention was applied. It is a longitudinal cross-sectional view which shows the valve open state which the ball | bowl separated from the seating part by exciting the solenoid valve shown in FIG. FIG. 3A is an enlarged vertical cross-sectional view showing a state in which a first coating layer is formed on the outer peripheral surface of the shaft by ion nitriding, and FIG. 3B shows thermal diffusion after the first coating layer is formed on the shaft. It is an enlarged longitudinal cross-sectional view which shows the state in which the thickness of the said 1st coating layer increased by the process and the 2nd coating layer was formed.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Solenoid valve 12 ... Solenoid part 14 ... Housing 16 ... Valve mechanism part 18 ... Valve body 20 ... Supply port 22 ... Discharge port 24 ... Communication path 26 ... Seating part 28 ... Ball 30 ... Coil 34 ... Ball guide 36 ... Shaft 38 ... Space part 40 ... Moving core 42 ... First coating layer 44 ... Second coating layer 46 ... Guide member 52 ... Fixing core part 54 ... Coil bobbin 62 ... Yoke 76 ... Coupler parts 78a, 78b, 80 ... O-ring

Claims (6)

A solenoid valve main body including a valve body having a first port and a second port through which a pressure fluid flows, and a housing;
A coil disposed inside the housing and wound around a coil bobbin; a yoke connected to one end of the housing; a movable core sucked by a fixed core portion under an energizing action on the coil; and the fixed core A solenoid part having a spring member interposed between the part and the movable core and returning the movable core to an initial position;
A shaft connected to the movable core and displaced integrally with the movable core , and a valve that contacts the end of the shaft and opens and closes the communication path between the first port and the second port under the displacement action of the shaft A valve mechanism having a body;
With
The shaft is formed of a metal material, and a first coating layer having a predetermined thickness is formed on the outer surface of the shaft by ion nitriding treatment, and the thickness of the first coating layer is increased by thermal diffusion treatment. A solenoid valve characterized by that. The solenoid valve according to claim 1, wherein
An electromagnetic valve characterized in that the valve body is formed with a valve body support portion that faces a seating portion on which the valve body is seated and supports the valve body so as to be displaceable along an axial direction. The solenoid valve according to claim 1, wherein
The electromagnetic valve according to claim 1, wherein the valve body is provided with a guide member that supports the shaft so as to be displaceable along an axial direction. The solenoid valve according to claim 1, wherein
A hardness of the shaft is set higher than the hardness of the valve body by the ion nitriding treatment, and is set lower than a hardness of the valve body by the thermal diffusion treatment. Solenoid valve. A solenoid valve main body including a valve body having a first port and a second port through which a pressure fluid flows, and a housing;
A coil disposed inside the housing and wound around a coil bobbin; a yoke connected to one end of the housing; a movable core sucked by a fixed core portion under an energizing action on the coil; and the fixed core A solenoid part having a spring member interposed between the part and the movable core and returning the movable core to an initial position;
A shaft connected to the movable core and displaced integrally with the movable core , and a valve that contacts the end of the shaft and opens and closes the communication path between the first port and the second port under the displacement action of the shaft A valve mechanism having a body;
With
The shaft is formed of a metal material, and a first coating layer having a predetermined thickness is formed on the outer surface of the shaft by ion nitriding treatment, and the thickness of the first coating layer is increased by thermal diffusion treatment. And a second coating layer is formed. A solenoid valve main body including a valve body having a first port and a second port through which a pressure fluid flows, and a housing;
A coil disposed inside the housing and wound around a coil bobbin; a yoke connected to one end of the housing; a movable core sucked by a fixed core portion under an energizing action on the coil; and the fixed core A solenoid part having a spring member interposed between the part and the movable core and returning the movable core to an initial position;
A shaft connected to the movable core and displaced integrally with the movable core , and a valve that contacts the end of the shaft and opens and closes the communication path between the first port and the second port under the displacement action of the shaft In a method for manufacturing a solenoid valve including a valve mechanism having a body,
Applying ion nitriding to the outer surface of the shaft;
Applying heat diffusion treatment to the outer surface of the shaft;
A method for manufacturing a solenoid valve, comprising:

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