Solenoid

Abstract

Provided is a solenoid having high heat dissipation performance. A solenoid (1) is provided with: a cylindrical housing (30); and a coil (39) disposed within the housing (30), the outer periphery of the coil (39) being covered by a resin molded part (35), at least a portion of the outer peripheral surface of the resin molded part (35) having a concave-convex shape.

Description

Technical Field

[0001] This invention relates to a solenoid that uses the magnetic effect of energizing a solenoid, such as a coil, to drive a movable iron core. Background Technology

[0002] Solenoids can be used as a means to operate various devices such as valves or machinery in various industrial fields. Solenoids operate various devices by electromagnetically moving a housed movable iron core, which is housed in a manner that allows it to reciprocate by energizing a coil.

[0003] Generally, a solenoid has: a solenoid housing made of a magnetic material; a coil housed inside the solenoid housing; a fixed iron core; and a movable iron core that generates a magnetic force between the fixed iron core and the movable iron core by energizing the coil, causing the movable iron core to move toward the fixed iron core. The movable iron core has a rod disposed on one axial end that abuts or connects to various devices.

[0004] For example, in the solenoid shown in Patent Document 1, the coil is molded with resin to protect it. The coil is inserted into the solenoid housing, and a plate, a plunger, and a fixed iron core are arranged inside the coil. When the coil is energized, a magnetic circuit is formed by the fixed iron core, housing, plate, plunger, and then the coil returns to the fixed iron core, and the plunger is magnetically attracted by the fixed iron core.

[0005] Existing technical documents

[0006] Patent documents

[0007] Patent Document 1: International Publication No. 2003 / 056579 (page 6) Figure 1 ) Summary of the Invention

[0008] The problem that the invention aims to solve

[0009] In a solenoid like that in Patent Document 1, the coil is covered with resin. Therefore, although the influence of external factors on the coil can be suppressed, the heat generated when energized is easily accumulated. Since the coil has the property that the resistance value increases with the temperature, the thrust of the movable iron core may be reduced.

[0010] This invention was made in response to such a problem, and its purpose is to provide a solenoid with high heat dissipation.

[0011] Methods for solving problems

[0012] To solve the above-mentioned problems, the solenoid of the present invention has: a cylindrical housing; and a coil disposed within the housing, the outer periphery of which is covered by a resin molding portion, wherein at least a portion of the outer peripheral surface of the resin molding portion is of an uneven shape.

[0013] Therefore, by using the concave and convex shape, the surface area of ​​the outer peripheral surface of the resin molding part is increased, and convection is generated between the shell and the outer peripheral surface of the resin molding part, which facilitates the transfer of heat to the shell and improves heat dissipation.

[0014] Alternatively, the convex portion of the concave-convex shape may extend circumferentially.

[0015] Therefore, it can dissipate heat over a large circumferential area.

[0016] Alternatively, the protrusion may extend throughout the entire circumference.

[0017] This allows for even heat dissipation in the circumferential direction.

[0018] Alternatively, multiple protrusions may be provided in the axial direction.

[0019] This allows for even heat dissipation along the axial direction.

[0020] Alternatively, the protrusion of the concave-convex shape may extend axially.

[0021] Therefore, when inserting the coil into the housing, the protrusion is less likely to interfere with the housing, allowing for easy assembly. Furthermore, it enables heat dissipation over a wide axial range.

[0022] Alternatively, the protrusions may be provided in multiple circumferential directions.

[0023] This allows for even heat dissipation in the circumferential direction.

[0024] Alternatively, the protrusions of the concave-convex shape may be radially separated from the housing.

[0025] As a result, convection is also generated in the fluid between the protrusion and the housing, which promotes heat dissipation of the coil.

[0026] Alternatively, the protruding part of the concave-convex shape may abut against the housing.

[0027] Thus, the contact between the housing and the protrusion promotes heat dissipation of the coil and stabilizes the coil's position.

[0028] Alternatively, the concave-convex shape may extend in a spiral shape, and the inner circumferential surface of the housing may have a concave-convex shape that can engage with the concave-convex shape.

[0029] Therefore, by screwing the concave and convex shapes of the resin molding part with the concave and convex shapes of the housing, heat dissipation of the coil is promoted, and the coil and housing can be positioned.

[0030] Alternatively, the concave-convex shape can be composed of concave and convex portions with a rectangular cross-section.

[0031] This ensures the strength of the protrusion and effectively increases the surface area. Attached Figure Description

[0032] Figure 1 This is a partial cross-sectional view of the solenoid of Embodiment 1 of the present invention.

[0033] Figure 2 This is a perspective view showing the solenoid molded body of Embodiment 1.

[0034] Figure 3 This is a schematic diagram showing the protrusion of the solenoid molded body of Embodiment 1.

[0035] Figure 4 This is a schematic diagram showing the protrusion of the solenoid molded body according to Embodiment 2 of the present invention.

[0036] Figure 5 This is a diagram showing the protrusion of the solenoid molded body according to Embodiment 3 of the present invention.

[0037] Figure 6 This is a diagram showing the protrusion of the solenoid molded body according to Embodiment 4 of the present invention.

[0038] Figure 7 This is a perspective view showing the solenoid molded body of Embodiment 5 of the present invention.

[0039] Figure 8 This is a cross-sectional view of the solenoid of Example 5 viewed from the axial direction.

[0040] Figure 9 This is a schematic diagram showing the protrusion of the solenoid molded body of Embodiment 5.

[0041] Figure 10 This is a perspective view showing the solenoid molded body of Embodiment 6 of the present invention.

[0042] Figure 11 This is a schematic diagram showing the screwed state of the solenoid molded body and the shell in Embodiment 6. Detailed Implementation

[0043] Hereinafter, the method of implementing the solenoid of the present invention will be described based on embodiments.

[0044] Example 1

[0045] Reference Figures 1 to 3 The solenoid of Example 1 will be described.

[0046] The solenoid 1 in this embodiment 1 will be described as a solenoid used for the solenoid valve V. Furthermore, the solenoid 1 is not limited to use for the solenoid valve V, and can be used in a solenoid actuator to operate any load.

[0047] like Figure 1 As shown, the solenoid valve V is used, for example, as a device controlled by the hydraulic pressure of a vehicle. Alternatively, the solenoid valve V is mounted vertically on a device (not shown) and used as a so-called oil-immersed type solenoid valve, immersed in working oil.

[0048] Solenoid valve V is constructed by integrally mounting solenoid 1 and valve 2, with valve 2 adjusting the fluid flow rate. Additionally, Figure 1 The diagram shows the open state of solenoid valve V when coil 39 is not energized.

[0049] Valve 2 consists of a sleeve 21, a valve core 22, and a helical spring 23 (not shown). The valve core 22 can approach and move away from the valve hole of the sleeve 21 (not shown), and the spring 23 applies force to the valve core 22 in a direction away from the valve hole. In addition, the sleeve 21 and the valve core 22 are made of materials such as aluminum, iron, stainless steel, and resin.

[0050] The solenoid 1 is mainly composed of a solenoid housing 30, a solenoid molded body 31, a fixed iron core 32, and a plunger 4 that serves as a movable iron core.

[0051] The solenoid housing 30 is formed into a cylindrical shape from a magnetic metal material such as iron. However, the solenoid housing 30 is not limited to a cylindrical shape; it can also be a cylindrical shape with other cross-sectional shapes.

[0052] The solenoid housing 30 has a through hole 30a. The through hole 30a is composed of an upper recess 30b, a lower recess 30c, and a stepped connecting hole portion 30d, which connects the upper recess 30b and the lower recess 30c.

[0053] A solenoid-shaped body 31 is disposed in the upper recess 30b. A valve 2 is disposed in the lower recess 30c. A fixing core 32 is disposed in the connecting hole 30d. The valve core 22 is pressed against the fixing core 32 by the spring 23 when the solenoid valve V is in the open state (see reference). Figure 1 ).

[0054] The solenoid molding body 31 is formed into a bottomed cylindrical shape by molding a substrate 36 and a coil 39 with resin. The coil 39 is wound around a concave section of a spool below the substrate 36. A bottom is formed on the top of the substrate 36, and a magnetic component 33 is inserted into the gap between the bottom and the spool with the coil 39 wound on it, thus integrating them with the resin. Hereinafter, the resin portion around the outer periphery of the coil 39 will be referred to as the resin molding portion 35.

[0055] A cover 38 is fitted above the solenoid body 31, which closes the upper opening of the solenoid housing 30. Power is supplied from the outside to the coil 39 of the solenoid body 31 via power lines embedded in the cover 38.

[0056] The magnetic component 33 is a ring-shaped and flat magnetic material, such as a magnetic metal material like iron, forming the magnetic circuit between the second cylindrical body 8 (described later) and the solenoid housing 30.

[0057] The fixed iron core 32 has a lower large-diameter portion 32a and an upper small-diameter portion 32b. A through hole 32c extending axially is formed in the center of the fixed iron core 32.

[0058] The large-diameter portion 32a of the fixed iron core 32 is disposed below the large-diameter portion 30e of the connecting hole portion 30d, and is clamped in the vertical direction by the bottom surface 30f of the large-diameter portion 30e and the sleeve 21.

[0059] A first cylindrical body 7, made of a non-magnetic material, is disposed above the portion of the solenoid housing 30 that divides into a communicating hole 30d. Furthermore, a second cylindrical body 8, made of a magnetic material, is disposed above the first cylindrical body 7.

[0060] The second cylindrical body 8 is a bottomed cylindrical shape with an opening at the bottom. The solenoid housing 30, the magnetic component 33, the second cylindrical body 8, the plunger 4, and the fixed iron core 32 form a magnetic circuit in this order.

[0061] The plunger 4 is formed into a cylindrical shape from a magnetic metal material such as iron. The plunger 4 is arranged in a way that allows it to move up and down within a space surrounded by the fixed iron core 32, the first cylindrical body 7, and the second cylindrical body 8.

[0062] A through hole 4a is formed in the center of the plunger 4, extending axially. A rod 5 is fitted into the through hole 4a. The rod 5 extends to the upper and lower sides of the plunger 4.

[0063] The upper end 5a of rod 5 is inserted through bearing 9, which is fixed to the second cylindrical body 8. The lower end 5b of rod 5 is inserted through through hole 32c of fixed iron core 32. Furthermore, the lower end face of rod 5 is in contact with valve core 22.

[0064] When coil 39 is energized, solenoid valve V is in the closed state, forming a magnetic circuit consisting of solenoid housing 30, fixed iron core 32, plunger 4, second cylindrical body 8, and magnetic component 33. This generates a magnetic force between fixed iron core 32 and plunger 4, causing plunger 4 to move downwards and press valve core 22 downwards (illustration omitted).

[0065] Next, the solenoid molded body 31 will be described in detail.

[0066] like Figure 1 As shown, the entire circumference of the coil 39 of the solenoid body 31 is covered by the solenoid housing 30.

[0067] like Figure 2 and Figure 3As shown, the outer peripheral surface of the resin molding portion 35 of the solenoid molding body 31 at part 31A has a concave-convex shape. That is, a plurality of protrusions 34 and recesses 37 are alternately provided in the vertical direction on the outer peripheral surface of the resin molding portion 35 (in this embodiment, there are 8 protrusions 34 and 7 recesses 37). The protrusions 34 and recesses 37 are generally rectangular in shape when viewed in cross-section.

[0068] The surface area of ​​the outer peripheral surface of the resin molding part 35 is increased by multiple protrusions 34 and recesses 37, facilitating the release of heat from the resin molding part 35 to the oil in contact with the outer peripheral surface. Heat is transferred from the oil to the solenoid housing 30, and this heat is transferred to the oil housed in the mounted equipment outside the solenoid housing 30. At this time, the oil heated from the solenoid molding body 31 convects, facilitating the transfer of heat to the solenoid housing 30.

[0069] Furthermore, the solenoid housing 30 is made of a metal with better thermal conductivity than the solenoid body 31, making it easier for heat transferred to the solenoid housing 30 to be transferred to the mounted equipment. This improves heat dissipation from the solenoid body 31 with the coil 39 when energized. Consequently, the increase in resistance of the coil 39 with temperature rise can be reduced, allowing the plunger 4 to be driven with higher thrust.

[0070] Furthermore, the protrusion 34 and the recess 37 extend in a ring shape along the circumference. This allows for heat dissipation over a wide area throughout the circumference, thus improving heat dissipation performance and suppressing temperature deviations in the coil 39 along the circumference. Additionally, the oil can flow along the circumference, further suppressing temperature deviations along the circumference.

[0071] Furthermore, the protrusions 34 and recesses 37 are alternately arranged in multiples in the axial direction, i.e., the vertical direction, which enables heat dissipation over a large range in the vertical direction, thus improving heat dissipation performance. Moreover, compared with the resin-molded part with a flat outer peripheral surface, heat dissipation can be evenly distributed in the vertical direction, thus suppressing temperature deviations of the coil 39 in the vertical direction.

[0072] Furthermore, since the protrusions 34 are arranged at equal intervals in the vertical direction, the temperature deviation of the coil 39 in the vertical direction can be suppressed more effectively.

[0073] Furthermore, the vertical width W1 of the protrusion 34 is greater than the vertical width W2 of the recess 37 (W1 > W2). As a result, the strength of the resin molding part 35 can be ensured and heat dissipation can be easily carried out to the outer diameter side of the protrusion 34, thus enabling effective heat dissipation.

[0074] Furthermore, the depth D1 of the recess 37 is less than the vertical width W2 of the recess 37 (D1 < W2). This ensures the strength of the protrusion 34 and allows the coil 39 to approach the solenoid housing 30.

[0075] Furthermore, the protrusion 34 and the recess 37 are rectangular in cross-section, which ensures the strength of the protrusion 34 and effectively increases the surface area. Additionally, the radial dimension of the resin molding portion 35 can be reduced, enabling the solenoid 1 to be miniaturized.

[0076] In this embodiment, the resin-molded portion 35 with the protrusion 34 is formed by injection molding, but it is not limited to this. For example, after forming a resin layer on the coil, the protrusion and concave portion can be formed by cutting the resin layer, or the protrusion can be formed by stacking the protrusion on the resin layer.

[0077] And, as Figure 3 As shown, each protrusion 34 is radially separated from the inner circumferential surface 30g of the solenoid housing 30. Oil is present in the radial gap S between the solenoid housing 30 and the solenoid forming body 31. As a result, due to the heat generated in the coil 39 when energized, convection occurs in the oil, thus facilitating heat transfer from the solenoid forming body 31 to the solenoid housing 30 and promoting heat dissipation.

[0078] Furthermore, with the drive of the plunger 4, the oil moves within the radial gap S between the solenoid housing 30 and the solenoid forming body 31. This allows for the supply of relatively cool oil to the outer peripheral surfaces of each protrusion 34 and the recesses 37, thus improving heat dissipation.

[0079] Furthermore, in this embodiment, the protrusion 34 is illustrated as being in a ring shape, but for example, it may also be C-shaped, or multiple protrusions may be arranged separately in the circumferential direction, or adjacent protrusions may be partially connected to each other in the axial direction. Also, in this embodiment, the protrusion 34 and the recess 37 are illustrated as having a rectangular cross-section, but the cross-section may also be other shapes.

[0080] Furthermore, in this embodiment, the fluid inside the solenoid housing 30 is exemplified as oil, but it is not limited to this and may also be a liquid other than oil, a gas, a gas-liquid mixture, etc.

[0081] Furthermore, in this embodiment, the fluid outside the solenoid housing 30, i.e., inside the installed device, is oil, but it is not limited to this; it can also be a liquid other than oil, a gas, a gas-liquid mixture, etc. Moreover, the fluids inside and outside the solenoid housing 30 can be different fluids.

[0082] Example 2

[0083] Next, refer to Figure 4 The solenoid of Example 2 will be described. Furthermore, repeated structural descriptions identical to those of Example 1 will be omitted.

[0084] like Figure 4As shown, in the solenoid molding body 231 of this embodiment 2, the protrusion 234 abuts against the inner circumferential surface 30g of the solenoid shell 30.

[0085] Thus, the protrusion 234 comes into contact with the solenoid housing 30, which is made of metal with high thermal conductivity, thereby enabling efficient heat dissipation from the coil 39. Furthermore, the heat from the coil 39 can be transferred evenly and comprehensively in the vertical direction of the solenoid housing 30 via the multiple protrusions 234 in the vertical direction.

[0086] Furthermore, the vertical width W1' of the protrusion 234 is greater than the vertical width W2' of the recess 237, thus facilitating the transfer of heat from the coil 39 to the solenoid housing 30 and enabling effective heat dissipation.

[0087] Furthermore, due to the heat generated in the coil 39 when energized, convection occurs in the oil within the space S' surrounded by the recess 237 and the solenoid housing 30, thus promoting heat dissipation.

[0088] Furthermore, the protrusion 234 and the recess 237 are rectangular in cross-section, which ensures the strength of the protrusion 234 and prevents the protrusion 234 from breaking when the solenoid molded body 231 is inserted into the solenoid housing 30.

[0089] Furthermore, the lower end face 231a of the solenoid body 231 abuts against the bottom surface 30h of the upper recess 30b of the solenoid housing 30, and the protrusion 234 at the lower end of the solenoid body 231 abuts against the inner circumferential surface 30g of the solenoid housing 30. Therefore, the solenoid housing 30 and the solenoid body 231 are not easily tilted relative to each other, and the position of the solenoid body 231 relative to the solenoid housing 30 is stable.

[0090] Example 3

[0091] Next, refer to Figure 5 The solenoid of Example 3 will be described. Furthermore, repeated structural descriptions identical to those of Example 2 will be omitted.

[0092] like Figure 5 As shown, the protrusion 334 of the solenoid molded body 331 in this embodiment is approximately triangular in cross-section. This reduces the contact area between the protrusion 334 and the inner circumferential surface 30g of the solenoid housing 30, making it easier to insert the solenoid molded body 331 into the solenoid housing 30.

[0093] Furthermore, the space S” between the protrusions 334 can be ensured to be large, so the oil retained in the space S” is less likely to become hot.

[0094] Furthermore, while the example illustrates a configuration where the protrusions 334 are axially separated, it is also possible for the inclined surfaces of adjacent protrusions to be axially connected. For instance, the outer peripheral surface of the resin molding portion can also be a wavy line such as a triangular wave or a sine wave.

[0095] Example 4

[0096] Next, refer to Figure 6 The solenoid of Example 4 will be described. Furthermore, repeated structural descriptions identical to those of Example 2 described above will be omitted.

[0097] like Figure 6 As shown, in the solenoid molded body 431 of this embodiment, the outer peripheral surface 434a of the protrusion 434 is an arc shape protruding outward in cross-section. Therefore, the corner of the protrusion 434 does not contact the inner peripheral surface 30g of the solenoid housing 30, making it easy to insert the solenoid molded body 431 into the solenoid housing 30. Furthermore, the protrusion 434 is less likely to break when the solenoid molded body 431 is inserted.

[0098] Furthermore, in this embodiment 4, the outer peripheral surface 434a of the protrusion 434 is shown to be arc-shaped. However, for example, the corners of the protrusion may be chamfered to make the outer peripheral surface of the protrusion flat. In addition, the chamfer is not limited to a curved surface, but may also be a straight surface.

[0099] Example 5

[0100] Next, refer to Figures 7-9 The solenoid of Example 5 will be described. Furthermore, repeated structural descriptions identical to those of Example 1 described above will be omitted.

[0101] like Figures 7-9 As shown, the protrusion 534 and recess 537 of the solenoid-shaped body 531 are generally rectangular in shape when viewed in section and extend along the axial direction. The protrusion 534 and recess 537 can dissipate heat over a large range in the axial direction.

[0102] Furthermore, since the protrusion 534 extends axially, it is easier to insert into the solenoid housing 30 compared to the circumferential extension method, i.e., the method of Embodiments 1 to 4. In addition, from the viewpoint of ease of insertion, it is preferable that the corner of the insertion-side end, i.e. the lower end, of the protrusion 534 is chamfered.

[0103] Furthermore, the protrusions 534 and concave portions 537 are provided in multiples in the circumferential direction, enabling heat dissipation over a large circumferential range, thus improving heat dissipation performance. Moreover, compared to a resin-molded portion with a flat outer circumferential surface, heat dissipation is more evenly distributed in the circumferential direction, thereby suppressing temperature deviations of the coil 39 in the circumferential direction.

[0104] Furthermore, the protrusion 534 has an outer peripheral surface 534a that extends parallel to the inner peripheral surface 30g of the solenoid housing 30 and is arc-shaped in cross-section. The outer peripheral surface 534a of the protrusion 534 contacts the inner peripheral surface 30g of the solenoid housing 30, thus enabling efficient heat dissipation of the coil 39 and preventing localized temperature distribution in the axial direction.

[0105] Furthermore, in the space S”’ within the recess 537, the oil convects axially, thereby further suppressing axial temperature deviation.

[0106] Furthermore, with the drive of the plunger 4, the oil moves within the space S”' in the recess 537. As a result, oil with a lower temperature can be supplied to the space S”', thus improving heat dissipation.

[0107] Thus, the solenoid molded body 531 of this embodiment can disperse temperature in the axial direction, and is therefore effective for the solenoid molded body 531, which is more prone to temperature deviation in the axial direction compared to the circumferential direction.

[0108] Furthermore, in this embodiment 5, the protrusion 534 is shown to contact the inner circumferential surface 30g of the solenoid housing 30, but it can also be separated radially as in embodiment 1.

[0109] Furthermore, the cross-sectional shape of the protrusion in Embodiments 3 and 4 can also be applied in Embodiment 5.

[0110] Furthermore, in this embodiment, the protrusion 534 extends continuously along the axial direction, but multiple protrusions may also be arranged separately in the axial direction. In this case, the protrusions may be staggered in the circumferential direction. Also, the protrusion 534 may be such that adjacent protrusions in the circumferential direction are partially connected to each other in the circumferential direction.

[0111] Example 6

[0112] Next, refer to Figure 10 and Figure 11 The solenoid of Example 6 will be described. Furthermore, repeated structural descriptions identical to those of Example 1 described above will be omitted.

[0113] like Figure 10 As shown, the protrusion 634 and concave portion 637 of the solenoid body 631 are roughly triangular in shape when viewed in section, and extend in a spiral shape with circumferential and axial components, which is called external thread.

[0114] And, as Figure 11 As shown, a convex portion 630a and a concave portion 630b extending in a spiral shape with circumferential and axial components are formed on the inner circumferential surface of the solenoid housing 630, which is called internal thread. The convex portion 630a and the concave portion 630b are approximately triangular in shape when viewed in cross section.

[0115] The solenoid body 631 is connected to the solenoid housing 630 by screwing the protrusion 634 and the recess 637 with the protrusion 630a and the recess 630b.

[0116] Therefore, the protrusions 634 and concave portions 637 of the solenoid body 631 are in contact with the protrusions 630a and concave portions 630b of the solenoid housing 630 over a large range, thus enabling efficient heat dissipation of the coil 39. Furthermore, the solenoid housing 630 and the solenoid body 631 are not prone to relative tilting, and the position of the solenoid body 631 relative to the solenoid housing 630 is stable.

[0117] The embodiments of the present invention have been described above based on the accompanying drawings, but the specific structure is not limited to these embodiments, and changes and additions without departing from the spirit of the present invention are also included in the present invention.

[0118] For example, in Examples 1 to 4, the protrusion is shown to be annular and extending radially; in Example 5, the protrusion extends axially; and in Example 6, the protrusion extends spirally. However, the protrusion may also be divided into multiple parts in the extending direction. Furthermore, the protrusion may not extend but may be distributed on the outer peripheral surface of the resin molding part.

[0119] Furthermore, in the aforementioned embodiments 1 to 6, a method of providing multiple protrusions was illustrated, but it is sufficient to provide only at least one.

[0120] Furthermore, in the aforementioned embodiments 1 to 6, the magnetic component and the coil are integrally formed, but it is also possible for the magnetic component and the coil to be separate parts.

[0121] Furthermore, in the aforementioned Examples 1 to 6, an oil-immersed solenoid valve was illustrated, but the environment in which the solenoid valve is installed can be freely changed to water, gas, atmosphere, etc.

[0122] Furthermore, in the aforementioned Examples 1 to 6, an example was described where the resin molding part was only provided on the outer diameter side of the coil. However, in addition to the outer diameter side of the coil, it can also be provided on the top, bottom, or inner diameter side.

[0123] Label Explanation

[0124] 1: Solenoid; 4: Plunger (movable iron core); 30: Solenoid housing (shell); 30g: Inner circumferential surface; 31: Solenoid molded body; 32: Fixed iron core; 34: Protrusion; 35: Resin molded part; 37: Recess; 39: Coil; V: Solenoid valve.

Claims

1. A solenoid having: a cylindrical housing; and a coil disposed in the housing, an outer periphery of the coil being covered by a resin molding portion, wherein at least a portion of an outer peripheral surface of the resin molding portion is in a concave-convex shape.

2. The solenoid according to claim 1, wherein the convex portion of the concave-convex shape extends in a circumferential direction.

3. The solenoid according to claim 2, wherein the convex portion extends over an entire circumference.

4. The solenoid according to claim 3, wherein a plurality of the convex portions are provided in an axial direction.

5. The solenoid according to claim 1, wherein the convex portion of the concave-convex shape extends in an axial direction.

6. The solenoid according to claim 5, wherein a plurality of the convex portions are provided in a circumferential direction.

7. The solenoid according to claim 1, wherein the convex portion of the concave-convex shape is separated from the housing in a radial direction.

8. The solenoid according to claim 1, wherein the convex portion of the concave-convex shape abuts against the housing.

9. The solenoid according to claim 8, wherein the concave-convex shape extends in a spiral shape, and has a concave-convex shape capable of being screwed with the concave-convex shape on an inner peripheral surface of the housing.

10. The solenoid according to any one of claims 1 to 8, wherein the concave-convex shape is constituted by a concave portion and a convex portion of a rectangular cross-sectional shape. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​

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