Solenoid valve

Abstract

A solenoid valve includes a valve body, a valve core, and a solenoid unit. The solenoid unit has a coil, a bobbin, a fixed iron core, a movable iron core, a biasing spring, a magnetic frame, and a molded resin. The magnetic frame has a frame end wall adjacent to the bobbin in the axial direction of the bobbin, two frame wrist portions, and an internal threaded hole that penetrates the frame end wall and engages with the fixed iron core. A cylindrical protruding portion protrudes from the end face of the frame end wall opposite to the bobbin, and this protruding portion forms part of the internal threaded hole. The molded resin has a molded end wall and a molded peripheral wall that cover the frame end wall. The molded end wall has a communication hole that communicates with the internal threaded hole, and a groove extending along the outer peripheral surface of the protruding portion is formed on the inner peripheral surface of the communication hole. According to the present invention, the magnetic efficiency can be improved, and a higher attracting force can be obtained on the fixed iron core.

Description

Technical Field

[0001] The present invention relates to a solenoid valve. Background Art

[0002] A solenoid valve is known, for example, from Japanese Utility Model Laid-Open No. 6-2621. Such a solenoid valve includes a valve element that switches a flow path formed in a valve body and a solenoid unit that moves the valve element. The solenoid unit has a coil, a cylindrical bobbin around which the coil is wound, a fixed iron core disposed inside the bobbin, a movable iron core, and a biasing spring that biases the movable iron core in a direction away from the fixed iron core. By supplying electric power to the coil, the movable iron core is attracted by the attractive force generated by the fixed iron core and is attracted to the fixed iron core. Further, the solenoid unit has a magnetic yoke and a molded resin that integrates the magnetic yoke, the bobbin, and the coil, wherein the magnetic yoke is located outside the bobbin and cooperates with the fixed iron core and the movable iron core around the coil to form a magnetic path. Summary of the Invention

[0003] Technical Problem to be Solved by the Invention

[0004] In a solenoid valve configured to integrate a magnetic yoke, a bobbin, and a coil with a molded resin, for example, injection molding is performed to fill the resin into a mold in a state where the magnetic yoke, the bobbin, and the coil are disposed in the mold. At this time, if the positioning of the magnetic yoke in the mold is unstable, the position of the magnetic yoke may deviate from a predetermined position due to the molding pressure of the resin in the mold. As a result, the magnetic yoke may be integrated with the bobbin and the coil by the molded resin in a state where the magnetic yoke deviates from a predetermined position relative to the bobbin and the coil. Therefore, around the coil, the magnetic path formed by the cooperation of the magnetic yoke, the fixed iron core, and the movable iron core becomes unstable, and the magnetic efficiency decreases. Once the magnetic efficiency decreases, it is difficult to obtain a high attractive force in the fixed iron core.

[0005] Solution to the Technical Problem

[0006] The solenoid valve of the present invention includes a valve body, a valve core, and a solenoid part; the above-mentioned valve body has a flow path; the above-mentioned valve core is configured to switch the above-mentioned flow path; the above-mentioned solenoid part is configured to move the above-mentioned valve core. The above-mentioned solenoid part has a coil, a cylindrical bobbin around which the above-mentioned coil is wound, a fixed iron core disposed inside the above-mentioned bobbin, a movable iron core, a biasing spring, a magnetic frame, and a molding resin. The movable iron core is configured to be attracted by the above-mentioned fixed iron core by the attraction generated by the above-mentioned fixed iron core when power is supplied to the above-mentioned coil. The biasing spring is configured to bias the above-mentioned movable iron core in a direction away from the above-mentioned fixed iron core. The magnetic frame is configured to be located outside the above-mentioned bobbin and cooperate with the above-mentioned fixed iron core and the above-mentioned movable iron core around the above-mentioned coil to form a magnetic path. The molding resin integrates the above-mentioned magnetic frame, the above-mentioned bobbin, and the above-mentioned coil. The above-mentioned magnetic frame has a frame end wall, two frame wrist portions, and an internal thread hole; the above-mentioned frame end wall is adjacent to the above-mentioned bobbin in the axial direction of the above-mentioned bobbin; the above-mentioned frame wrist portions extend from the outer peripheral portion of the above-mentioned frame end wall in the axial direction of the above-mentioned bobbin outside the above-mentioned bobbin; the above-mentioned internal thread hole penetrates the above-mentioned frame end wall and is screwed with the above-mentioned fixed iron core. A cylindrical protrusion protrudes from the end surface of the above-mentioned frame end wall opposite to the above-mentioned bobbin, and the protrusion forms a part of the above-mentioned internal thread hole. The above-mentioned molding resin has a molding end wall and a molding peripheral wall; the above-mentioned molding end wall covers the above-mentioned frame end wall; the above-mentioned molding peripheral wall extends along the two above-mentioned frame wrist portions from the outer peripheral portion of the above-mentioned molding end wall, integrating the two above-mentioned frame wrist portions, the above-mentioned bobbin, and the above-mentioned coil. The above-mentioned molding end wall has a communication hole communicating with the above-mentioned internal thread hole, and a groove extending along the outer peripheral surface of the above-mentioned protrusion is formed on the inner peripheral surface of the communication hole.

[0007] Effects of the Invention

[0008] According to the present invention, the magnetic efficiency can be improved, and a higher attraction force can be obtained on the fixed iron core. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 It is a cross-sectional view of the solenoid valve in the embodiment.

[0010] Figure 2 It shows Figure 1 A perspective view of a part of the solenoid part of the solenoid valve.

[0011] Figure 3 It is Figure 2 A perspective view of the magnetic frame.

[0012] Figure 4 It is Figure 1 A front view of the solenoid part.

[0013] Figure 5 It is for explaining Figure 1 A cross-sectional view of the process of injection molding the molding resin in the solenoid valve.

[0014] Figure 6 is a cross-sectional view for explaining the process of injection molding a molding resin in a solenoid valve Figure 1 as described below.

[0015] Figure 7 is a cross-sectional view for explaining the process of injection molding a molding resin in a solenoid valve Figure 1 as described below. DETAILED DESCRIPTION

[0016] Hereinafter, an embodiment of the solenoid valve will be specifically described Figures 1 to 7 as follows.

[0017] As Figure 1 shown, the solenoid valve 10 includes a rectangular block-shaped valve body 11. The valve body 11 is made of a non-magnetic material. The valve body 11 is made of, for example, a synthetic resin material. In addition, the solenoid valve 10 includes a valve core 12 for switching a flow path formed in the valve body 11 and a solenoid unit 30 for moving the valve core 12.

[0018] A supply port 13, an output port 14, and a discharge port 15 are formed on one side surface of the valve body 11. The supply port 13 is connected to a positive pressure supply source (not shown) through a pipe (not shown). The output port 14 is connected to a pneumatic machine (not shown) through a pipe (not shown). The discharge port 15 is connected to the outside through a pipe (not shown).

[0019] A first recess 16 is formed on the first end surface 11a of the valve body 11. The first recess 16 is circular hole-shaped. In addition, a second recess 17 is formed on the second end surface 11b of the valve body 11. The second recess 17 is circular hole-shaped. The axis of the second recess 17 coincides with the axis of the first recess 16.

[0020] A plug 18 is attached to the first end surface 11a of the valve body 11. The plug 18 has a flat plate-shaped mounting portion 18a and a cylindrical portion 18b having a circular cross-sectional shape. The cylindrical portion 18b protrudes from the central portion of the mounting portion 18a. The cylindrical portion 18b is inserted into the first recess 16. The mounting portion 18a is attached to the first end surface 11a of the valve body 11. In addition, a valve chamber 19 is defined by the first recess 16 and the cylindrical portion 18b of the plug 18. The plug 18 and the valve body 11 are sealed by a sealing portion 20.

[0021] The valve core 12 is accommodated in the valve chamber 19. In addition, a valve guide 21 is accommodated in the valve chamber 19. The valve guide 21 is arranged around the valve core 12 and guides the valve core 12. The valve guide 21 is cylindrical. The valve guide 21 has a pair of extended pieces 22. The pair of extended pieces 22 respectively protrude from the end surface of the valve guide 21 facing the inner end surface of the first recess 16. The pair of extended pieces 22 penetrate through the valve body 11 and protrude into the second recess 17. Here, for the convenience of illustration, Figure 1It only represents one of a pair of extension pieces 22.

[0022] The solenoid valve 10 has a supply passage 23, an output passage 24, and a discharge passage 25. The supply passage 23 penetrates through the cylindrical portion 18b of the plug 18 and the valve body 11 and connects the supply port 13 to the valve chamber 19. The supply passage 23 has an open end that opens toward the front end face of the cylindrical portion 18b of the plug 18 in order to communicate with the valve chamber 19. The output passage 24 penetrates through the valve body 11 and connects the output port 14 to the valve chamber 19. The output passage 24 has an open end that opens toward the inner peripheral surface of the first recess 16 in order to communicate with the valve chamber 19. The discharge passage 25 penetrates through the valve body 11 and connects the discharge port 15 to the valve chamber 19. The discharge passage 25 has an open end that opens toward the inner end face of the first recess 16 in order to communicate with the valve chamber 19.

[0023] The plug 18 has a supply valve seat 26. The supply valve seat 26 is formed around the open end of the supply passage 23 that opens toward the front end face of the cylindrical portion 18b of the plug 18. The supply valve seat 26 can seat the valve core 12. The valve body 11 has a discharge valve seat 27. The discharge valve seat 27 is formed around the open end of the discharge passage 25 that opens toward the inner end face of the first recess 16 of the valve body 11. The discharge valve seat 27 can seat the valve core 12. The valve core 12 can contact and separate from the supply valve seat 26 and the discharge valve seat 27 respectively. The valve core 12 moves integrally with the valve guide 21.

[0024] The solenoid valve 10 includes a valve core spring 28. The valve core spring 28 is housed in the valve chamber 19. The valve core spring 28 is interposed between the valve core 12 and the plug 18 in the valve chamber 19. The valve core spring 28 biases the valve core 12 toward the discharge valve seat 27.

[0025] The solenoid unit 30 has a coil 31, a bobbin 32, a fixed iron core 33, a movable iron core 34, a biasing spring 35, a magnetic frame 36, a molding resin 37, and a magnetic member 38.

[0026] The bobbin 32 is cylindrical. In the present embodiment, the bobbin 32 has a circular cross-sectional shape. The bobbin 32 is made of a resin material. The two end portions in the axial direction of the bobbin 32 include a first end portion and a second end portion, where the first end portion is farther from the valve body 11 and the second end portion is closer to the valve body 11. The coil 31 is wound around the bobbin 32. The fixed iron core 33 is made of a magnetic material. The fixed iron core 33 is cylindrical. The fixed iron core 33 has a shaft portion 33a and an external thread portion 33b. The shaft portion 33a is disposed inside the bobbin 32 near the first end portion of the bobbin 32. The axis of the shaft portion 33a coincides with the axis of the bobbin 32. The external thread portion 33b is continuous with the first end portion of the shaft portion 33a. The external thread portion 33b protrudes from the first end portion of the bobbin 32.

[0027] The movable iron core 34 is made of a magnetic material. The movable iron core 34 is cylindrical. The movable iron core 34 is inserted into the inside of the bobbin 32 from the second end portion of the bobbin 32. The axis of the movable iron core 34 coincides with the axis of the bobbin 32. The movable iron core 34 is adjacent to the fixed iron core 33 in the axial direction of the bobbin 32. The movable iron core 34 has a protruding end portion that protrudes from the second end portion of the bobbin 32 on the side opposite to the fixed iron core 33. The movable iron core 34 has a flange portion 34a. The flange portion 34a extends outward in the radial direction from the protruding end portion of the movable iron core 34.

[0028] As Figure 1 and Figure 2 shown, the magnetic frame 36 has a frame end wall 36a and a pair of frame arm portions 36b. The frame end wall 36a is a rectangular flat plate. The frame end wall 36a is adjacent to the first end portion of the bobbin 32 in the axial direction of the bobbin 32. The magnetic frame 36 is disposed on the bobbin 32 in a state where the thickness direction of the frame end wall 36a coincides with the axial direction of the bobbin 32.

[0029] The frame end wall 36a has an inner end face and an outer end face, where the inner end face faces the bobbin 32 and the outer end face faces the side opposite to the bobbin 32. A protruding portion 40 protrudes from the outer end face of the frame end wall 36a. The protruding portion 40 is annular or cylindrical. In the present embodiment, the protruding portion 40 has a circular cross-sectional shape. The outer peripheral surface of the protruding portion 40 has a pair of flat surfaces 40a that extend parallel to each other. The pair of flat surfaces 40a are respectively disposed on both sides of the axis of the protruding portion 40 on a line perpendicular to the axis of the protruding portion 40. In the present embodiment, the line perpendicular to the axis of the protruding portion 40 and on which the pair of flat surfaces 40a are disposed is a diagonal line connecting two corner portions of the substantially rectangular frame end wall 36a. That is, the pair of flat surfaces 40a are disposed at positions corresponding to a pair of diagonal portions of the substantially rectangular frame end wall 36a. In addition, the magnetic frame 36 has an internal threaded hole 41. The internal threaded hole 41 penetrates the frame end wall 36a in the thickness direction. The protruding portion 40 is formed as a part of the internal threaded hole 41. The inside of the internal threaded hole 41 communicates with the inside of the bobbin 32. The axis of the internal threaded hole 41 coincides with the axis of the bobbin 32. The internal threaded hole 41 is screwed with the external threaded portion 33b of the fixed iron core 33. By inserting the shaft portion 33a through the internal threaded hole 41 into the inside of the bobbin 32 and screwing the external threaded portion 33b with the internal threaded hole 41, the fixed iron core 33 is fixed to the magnetic frame 36.

[0030] As Figure 2 and Figure 3 shown, the frame end wall 36a has a pair of notch portions 42. The pair of notch portions 42 are respectively disposed on both sides of the axis of the internal threaded hole 41 on a line perpendicular to the axis of the internal threaded hole 41. In the present embodiment, the pair of notch portions 42 are respectively formed at a pair of diagonal portions of the substantially rectangular frame end wall 36a.

[0031] A pair of frame wrists 36b are in the shape of thin plate flats. The pair of frame wrists 36b extend parallel to each other from the outer peripheral portion of the frame end wall 36a. The thickness directions of the pair of frame wrists 36b are the same as each other. The thickness direction of each frame wrist 36b is perpendicular to the thickness direction of the frame end wall 36a. The pair of frame wrists 36b respectively extend from two parallel outer edge portions among the four outer edge portions of the frame end wall 36a that are located on both sides of the internal thread hole 41. The pair of frame wrists 36b extend from the outer peripheral portion of the frame end wall 36a to the axial direction of the bobbin 32 on the outside of the bobbin 32. Therefore, the magnetic frame 36 is located on the outside of the bobbin 32. As Figure 3 shown, the pair of frame wrists 36b are symmetrically shaped with respect to the axis of the internal thread hole 41.

[0032] As Figure 2 shown, a pair of terminal holding portions 32a project from the end surface of the bobbin 32 adjacent to the frame end wall 36a. Each terminal holding portion 32a is integrally formed with the bobbin 32. The pair of terminal holding portions 32a are respectively engaged with a pair of notch portions 42. Therefore, the pair of terminal holding portions 32a are respectively engaged with the frame end wall 36a at positions on a line perpendicular to the axis of the internal thread hole 41 and on both sides of the axis of the internal thread hole 41. In the present embodiment, the pair of terminal holding portions 32a are engaged with the frame end wall 36a at a pair of diagonal portions of the substantially rectangular frame end wall 36a. The front end surface of each terminal holding portion 32a projects beyond the outer end surface of the frame end wall 36a. Terminals 43 project from each terminal holding portion 32a. Each terminal 43 is electrically connected to the coil 31.

[0033] As Figure 1 shown, the molding resin 37 is in the shape of a quadrangular block. The molding resin 37 is, for example, a thermoplastic resin. The molding resin 37 has a molding end wall 37a and a molding peripheral wall 37b. The molding end wall 37a covers the frame end wall 36a. The molding end wall 37a covers the outer end surface of the frame end wall 36a. Each terminal 43 penetrates the molding end wall 37a and projects from the molding end wall 37a.

[0034] A communication hole 50 is formed in the molding end wall 37a. The communication hole 50 is in the shape of a circular hole. The communication hole 50 communicates with the internal thread hole 41. The axis of the communication hole 50 coincides with the axis of the internal thread hole 41. The diameter of the communication hole 50 is larger than the outer diameter of the protruding portion 40. The inner peripheral surface of the communication hole 50 extends along the outer peripheral surface of the protruding portion 40. The front end surface of the protruding portion 40 is located inside the communication hole 50.

[0035] As Figure 4As shown, two grooves 51 are formed on the inner peripheral surface of the communication hole 50. The two grooves 51 extend along a pair of flat surfaces 40a of the protruding portion 40 respectively. The circumferential lengths of the two grooves 51 are the same as each other. The two grooves 51 are respectively disposed on both sides of the axis of the communication hole 50 on a line perpendicular to the axis of the communication hole 50. In the present embodiment, the two grooves 51 are disposed at positions corresponding to two diagonal portions of the molded end wall 37a having a substantially rectangular shape. The inside of the communication hole 50 is filled with an adhesive 52. A part of the adhesive 52 filled inside the communication hole 50 is filled in each groove 51. In addition, the adhesive 52 filled in each groove 51 adhesively bonds the molded resin 37 to a part of the outer peripheral surface of the protruding portion 40 to each other. In this way, the problem that the magnetic frame 36 rotates about the axis of the internal thread hole 41 can be suppressed.

[0036] As Figure 1 shown, the molded peripheral wall 37b extends from the outer peripheral portion of the molded end wall 37a along a pair of frame wrist portions 36b. A part of the molded peripheral wall 37b extends along the outer surfaces of the pair of frame wrist portions 36b respectively. The pair of frame wrist portions 36b have a base end portion connecting the frame end wall 36a and a front end portion on the side opposite to the base end portion. The molded peripheral wall 37b has a base end portion connecting the molded end wall 37a and a front end portion on the side opposite to the base end portion. The front end portion of the frame wrist portion 36b protrudes from the front end portion of the molded peripheral wall 37b. The molded peripheral wall 37b covers the entire coil 31 and the bobbin 32 from the outer side in the radial direction of the bobbin 32. Therefore, a part of the molded peripheral wall 37b is located between each frame wrist portion 36b and the coil 31 and between each frame wrist portion 36b and the bobbin 32. The molded peripheral wall 37b integrates the pair of frame wrist portions 36b, the bobbin 32, and the coil 31. Therefore, the molded resin 37 integrates the magnetic frame 36, the bobbin 32, and the coil 31.

[0037] The magnetic member 38 has a rectangular flat plate shape. The magnetic member 38 is formed with a through hole 38a. The through hole 38a penetrates the magnetic member 38 in the thickness direction. The magnetic member 38 is adjacent to the second end portion of the bobbin 32 in the axial direction of the bobbin 32. The magnetic member 38 is disposed inside the front end portions of the pair of frame wrist portions 36b. The movable iron core 34 passes through the inside of the through hole 38a.

[0038] The biasing spring 35 is interposed between the magnetic member 38 and the flange portion 34a of the movable iron core 34. One end of the biasing spring 35 is supported by the magnetic member 38, and at the same time, the other end of the biasing spring 35 is supported by the flange portion 34a of the movable iron core 34. The biasing spring 35 biases the movable iron core 34 in a direction away from the fixed iron core 33. The spring force of the biasing spring 35 is greater than the spring force of the valve core spring 28.

[0039] The solenoid unit 30 is connected to the valve body 11 by the molding resin 37 and thus disposed in the valve body 11. The molding resin 37 is connected to the valve body 11, and the end of the movable iron core 34 on the side opposite to the fixed iron core 33 protrudes into the second recess 17. The pair of extension pieces 22 of the valve element 12 abut against the end face of the movable iron core 34 on the side opposite to the fixed iron core 33.

[0040] The end of the molding resin 37 on the side opposite to the valve body 11 is connected to the power supply unit 60. The power supply unit 60 and the molding resin 37 are sealed by an annular sealing member 61. The power supply unit 60 has a circuit board 62. Each terminal 43 is electrically connected to the circuit board 62. Electric power is supplied to the coil 31 via the circuit board 62 and the terminal 43, so that the coil 31 is excited and a magnetic flux is generated around the coil 31. The generated magnetic flux sequentially passes through the fixed iron core 33, the magnetic yoke 36, the magnetic member 38, and the movable iron core 34. Therefore, the magnetic yoke 36 forms a magnetic circuit around the coil 31 in cooperation with the fixed iron core 33 and the movable iron core 34.

[0041] When electric power is supplied to the coil 31 to excite the coil 31 and a magnetic flux is generated around the coil 31, an attractive force is generated in the fixed iron core 33 due to the excitation of the coil 31. Due to the generated attractive force, the movable iron core 34 is attracted to the fixed iron core 33 against the elastic force of the biasing spring 35. Therefore, the movable iron core 34 is attracted to the fixed iron core 33 by the attractive force generated in the fixed iron core 33 by supplying electric power to the coil 31. Then, the valve element 12 moves in a direction away from the supply valve seat 26 under the elastic force of the valve element spring 28 and then seats on the discharge valve seat 27. In this way, the supply passage 23 is opened and the discharge passage 25 is closed. Therefore, the supply port 13 and the output port 14 communicate with each other via the supply passage 23, the valve chamber 19, and the output passage 24, and the communication between the output port 14 and the discharge port 15 via the output passage 24, the valve chamber 19, and the discharge passage 25 is blocked.

[0042] On the other hand, when the supply of electric power to the coil 3 is stopped, the attractive force of the fixed iron core 33 caused by the excitation of the coil 31 disappears. Therefore, the movable iron core 34 moves in a direction away from the fixed iron core 33 due to the elastic force of the biasing spring 35. Then, the movable iron core 34 presses the pair of extension pieces 22, and the valve element 12 moves toward the supply valve seat 26 against the elastic force of the valve element spring 28 and then seats on the supply valve seat 26. In this way, the supply passage 23 is closed and the discharge passage 25 is opened. Therefore, the output port 14 and the discharge port 15 communicate with each other via the output passage 24, the valve chamber 19, and the discharge passage 25, and the communication between the supply port 13 and the output port 14 via the supply passage 23, the valve chamber 19, and the output passage 24 is blocked.

[0043] AsFigure 5 As shown, when injection molding the resin 37, the mold 70 is used. The mold 70 has a mold body 71, a first jig 72, and a second jig 73. The first jig 72 is cylindrical. The first jig 72 has a pair of gripping pieces 72a. The pair of gripping pieces 72a project from the end face of the first jig 72. Each gripping piece 72a is a plate member having a bow-shaped cross section and has a surface extending along each flat surface 40a of the protruding portion 40. The pair of gripping pieces 72a are respectively disposed on both sides of the axis of the first jig 72 on a line perpendicular to the axis of the first jig 72. The second jig 73 is cylindrical. The second jig 73 can be inserted into the inside of the bobbin 32 through the through hole 38a of the magnetic member 38. In addition, the second jig 73 is configured to be able to close the through hole 38a.

[0044] As Figure 6 shown, when injection molding the resin 37, first, the magnetic frame 36, the bobbin 32, the coil 31, and the magnetic member 38 are respectively arranged at predetermined positions in the mold body 71. Then, the first jig 72 is arranged so that the pair of gripping pieces 72a are respectively in contact with the pair of flat surfaces 40a of the protruding portion 40. In this way, the magnetic frame 36 is positioned. The opening of the protruding portion 40 is closed by the end face of the first jig 72. In addition, the second jig 73 is inserted into the inside of the bobbin 32 through the through hole 38a of the magnetic member 38. In this way, the bobbin 32 and the magnetic member 38 are positioned. The through hole 38a is closed by the second jig 73.

[0045] As Figure 7 shown, by filling the molten resin in the mold body 71 and curing it, the molded resin 37 is formed. The molded resin 37 formed in the above manner integrates the magnetic frame 36, the bobbin 32, the coil 31, and the magnetic member 38.

[0046] Next, the operation of this embodiment will be described.

[0047] When injection molding and filling the resin into the mold body 71 in a state where the magnetic frame 36, the bobbin 32, and the coil 31 are arranged in the mold body 71, the outer peripheral surface of the protruding portion 40 comes into contact with a part of the mold 70, that is, the pair of gripping pieces 72a. Therefore, it is possible to suppress the problem that the position of the magnetic frame 36 deviates from the predetermined position due to the molding pressure of the resin in the mold body 71. As a result, the magnetic frame 36 is integrated with the molded resin 37 at a predetermined position relative to the bobbin 32 and the coil 31. Therefore, the magnetic circuit formed by the cooperation of the magnetic frame 36 around the coil 31 with the fixed iron core 33 and the movable iron core 34 is stabilized.

[0048] The above embodiment can obtain the following effects.

[0049] (1) A groove 51 is formed on the inner peripheral surface of the communication hole 50 and extends along the outer peripheral surface of the protruding portion 40. The groove 51 is formed in the following manner: for example, when performing injection molding to fill the resin into the mold 70 in a state where the magnetic frame 36, the bobbin 32, and the coil 31 are arranged in the mold 70, a part of the mold 70 is brought into contact with the outer peripheral surface of the protruding portion 40. Since the outer peripheral surface of the protruding portion 40 comes into contact with a part of the mold 70 during injection molding, it is possible to suppress the problem that the position of the magnetic frame 36 deviates from the predetermined position due to the molding pressure of the resin in the mold 70. As a result, the magnetic frame 36 is integrated with the bobbin 32 and the coil 31 by the molding resin 37 at a predetermined position. Therefore, around the coil 31, the magnetic circuit formed by the cooperation of the magnetic frame 36, the fixed iron core 33, and the movable iron core 34 is stabilized. Therefore, the magnetic efficiency can be improved, and a higher attractive force can be obtained on the fixed iron core 33.

[0050] (2) The outer peripheral surface of the protruding portion 40 has a pair of flat surfaces 40a extending parallel to each other. The pair of grooves 51 extend along the pair of flat surfaces 40a of the protruding portion 40, respectively. In this way, when performing injection molding to fill the resin into the mold 70 in a state where the magnetic frame 36, the bobbin 32, and the coil 31 are arranged in the mold 70, a part of the mold 70 comes into contact with the pair of flat surfaces 40a of the protruding portion 40, respectively. Therefore, it is possible to suppress the problem that the magnetic frame 36 rotates about the axis of the internal thread hole 41 due to the molding pressure of the resin in the mold 70. Therefore, it is possible to further suppress the problem that the position of the magnetic frame 36 deviates from the predetermined position.

[0051] (3) The pair of flat surfaces 40a are respectively arranged on both sides of the axis of the protruding portion 40 on a line perpendicular to the axis of the protruding portion 40. In this way, when performing injection molding to fill the resin into the mold 70 in a state where the magnetic frame 36, the bobbin 32, and the coil 31 are arranged in the mold 70, it is possible to bring a part of the mold 70 into contact with the parts on both sides of the axis of the protruding portion 40 on a line perpendicular to the axis of the protruding portion 40 in the outer peripheral surface of the protruding portion 40, respectively. Therefore, it is possible to further suppress the problem that the position of the magnetic frame 36 deviates from the predetermined position due to the molding pressure of the resin in the mold 70.

[0052] (4) The pair of frame wrists 36b are symmetrical with respect to the axis of the internal threaded hole 41. Thus, compared with the case where the pair of frame wrists 36b are asymmetrical with respect to the axis of the internal threaded hole 41, for example, when performing injection molding to fill resin into the mold 70 with the magnetic frame 36, the bobbin 32, and the coil 31 arranged in the mold 70, the amount of resin flowing around each of the pair of frame wrists 36b can be made uniform. Therefore, it is possible to avoid the problem that the stress accompanying the molding pressure of the resin in the mold 70 is concentrated on one side of the pair of frame wrists 36b. Therefore, it is possible to suppress the problem that the position of the magnetic frame 36 deviates from the predetermined position.

[0053] (5) The pair of terminal holding portions 32a are respectively engaged with the frame end walls 36a at positions on a line perpendicular to the axis of the internal threaded hole 41 and on both sides of the axis of the internal threaded hole 41. Therefore, the magnetic frame 36 can be accurately positioned with respect to the bobbin 32.

[0054] (6) An adhesive 52 is filled inside the communication hole 50. Thus, a part of the adhesive 52 filled inside the communication hole 50 is filled into each groove 51. Through the adhesive 52 filled in each groove 51, the molding resin 37 and a part of the outer peripheral surface of the protrusion 40 are adhesively bonded to each other. In this way, it is possible to suppress the problem that the magnetic frame 36 rotates about the axis of the internal threaded hole 41.

[0055] (7) The front end surface of the protrusion 40 is located inside the communication hole 50. Thus, compared with the case where the front end surface of the protrusion 40 protrudes from the communication hole 50 to the outside, for example, the adhesive 52 filled inside the communication hole 50 is more likely to stay inside the communication hole 50. Therefore, it is possible to suppress the problem that a part of the adhesive 52 filled inside the communication hole 50 flows out from the communication hole 50 to the outside.

[0056] (8) According to the present embodiment, since the problem that the position of the magnetic frame 36 deviates from the predetermined position is suppressed, the insulation distance between the magnetic frame 36 and the coil 31 can be ensured.

[0057] (9) According to the present embodiment, when performing injection molding, the amount of resin flowing around each of the pair of frame wrists 36b is more likely to be uniform. Therefore, it is possible to suppress the problem that the stress accompanying the molding pressure of the resin acts locally on the coil 31.

[0058] (10) The protrusion 40 forms a part of the internal threaded hole 41 for screwing the fixed iron core 33. Therefore, compared with the case where the protrusion 40 is not formed on the frame end wall 36a, since the magnetic path area between the magnetic frame 36 and the fixed iron core 33 can be increased, the magnetic efficiency can be improved.

[0059] Among them, the above-described embodiments can be implemented with changes as follows. The above-described embodiments and the following modification examples can be implemented in combination with each other within a technically non-contradictory range.

[0060] · In the embodiment, the outer peripheral surface of the protruding portion 40 may not have a pair of flat surfaces 40a extending parallel to each other, and the outer peripheral surface of the protruding portion 40 may be a perfect circular shape.

[0061] · In the embodiment, the pair of flat surfaces 40a may not be respectively arranged on a line perpendicular to the axis of the protruding portion 40 and on both sides of the axis of the protruding portion 40.

[0062] · In the embodiment, the pair of frame wrist portions 36b may be asymmetric with respect to the axis of the internal thread hole 41.

[0063] · In the embodiment, the front end surface of each terminal holding portion 32a may not protrude beyond the outer end surface of the frame end wall 36a.

[0064] · In the embodiment, the pair of terminal holding portions 32a may not be engaged with the frame end wall 36a respectively.

[0065] · In the embodiment, the inside of the communication hole 50 may not be filled with the adhesive 52.

[0066] · In the embodiment, the front end surface of the protruding portion 40 may protrude outward from the communication hole 50.

[0067] · In the embodiment, the inner peripheral surface of the communication hole 50 may be formed with three or more grooves 51.

[0068] · In the embodiment, the groove 51 may be formed to extend over the entire circumference of the inner peripheral surface of the communication hole 50.

[0069] · The "ring-shaped" used in this specification refers to any structure that forms a ring shape as a whole. The shape of the "ring-shaped" includes a circle, an ellipse, and a polygon with acute or rounded corners, but is not limited thereto. The "tubular" refers to any structure having a cross-sectional shape of a circle, an ellipse, and a polygon with acute or obtuse corners, but is not limited thereto. In the embodiment, the protruding portion 40 may be, for example, a quadrangular tubular shape.

[0070] Description of Reference Numerals

[0071] 10 Solenoid valve

[0072] 11 Valve body

[0073] 12 Spool

[0074] 30 Solenoid part

[0075] 31 Coil

[0076] 32 Bobbin

[0077] 32a Terminal holding part

[0078] 33 Fixed iron core

[0079] 34 Movable iron core

[0080] 35 Biasing spring

[0081] 36 Magnetic frame

[0082] 36a Frame end wall

[0083] 36b Frame wrist part

[0084] 37 Molding resin

[0085] 37a Molding end wall

[0086] 37b Molding peripheral wall

[0087] 40 Protrusion

[0088] 40a Flat surface

[0089] 41 Internal threaded hole

[0090] 50 Communication hole

[0091] 51 Groove

[0092] 52 Adhesive

Claims

1. A solenoid valve, wherein, it includes a valve body, a spool and a solenoid part, the valve body has a flow path, the spool is configured to switch the flow path, the solenoid part is configured to move the spool, the solenoid part has a coil, a cylindrical bobbin, a fixed iron core, a movable iron core, a biasing spring, a magnetic yoke and a molded resin, the bobbin is wound with the coil, the fixed iron core is disposed inside the bobbin, the movable iron core is configured to be attracted by the fixed iron core by the attraction generated by the fixed iron core when power is supplied to the coil, the biasing spring is configured to bias the movable iron core in a direction away from the fixed iron core, the magnetic yoke is configured to be located outside the bobbin and cooperate with the fixed iron core and the movable iron core to form a magnetic path around the coil, the molded resin integrates the magnetic yoke, the bobbin and the coil, the magnetic yoke has a frame end wall, two frame arm portions and an internal threaded hole, the frame end wall is adjacent to the bobbin in the axial direction of the bobbin, the frame arm portions extend from the outer peripheral portion of the frame end wall in the axial direction of the bobbin outside the bobbin, the internal threaded hole penetrates the frame end wall and is screwed with the fixed iron core, a cylindrical protruding portion protrudes from the end face of the frame end wall opposite to the bobbin, and the protruding portion forms a part of the internal threaded hole, the molded resin has a molded end wall and a molded peripheral wall, the molded end wall covers the frame end wall, the molded peripheral wall extends along the two frame arm portions from the outer peripheral portion of the molded end wall to integrate the two frame arm portions, the bobbin and the coil, the molded end wall has a communication hole communicating with the internal threaded hole, a groove extending along the outer peripheral surface of the protruding portion is formed on the inner peripheral surface of the communication hole.

2. The solenoid valve according to claim 1, wherein, two of the grooves are formed on the inner peripheral surface of the communication hole, the outer peripheral surface of the protruding portion has two flat surfaces extending parallel to each other, the two grooves respectively extend along the two flat surfaces.

3. The solenoid valve according to claim 2, wherein, the two flat surfaces are respectively disposed on both sides of the axis of the protruding portion on a line perpendicular to the axis of the protruding portion.

4. The solenoid valve according to claim 1, wherein, the two frame arm portions are symmetrically shaped with respect to the axis of the internal threaded hole.

5. The solenoid valve according to claim 1, wherein, two terminal holding portions protrude from the end face of the bobbin adjacent to the frame end wall, the two terminal holding portions are respectively engaged with the frame end wall at positions on a line perpendicular to the axis of the internal threaded hole and on both sides of the axis of the internal threaded hole.

6. The solenoid valve according to any one of claims 1 to 5, wherein, an adhesive is filled inside the communication hole.

7. The solenoid valve according to claim 6, wherein, the front end face of the protruding portion is located inside the communication hole.

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