Solenoid, shock absorber, and method for manufacturing solenoid

Abstract

To provide a solenoid structure capable of shortening the axial length.SOLUTION: A solenoid includes a bobbin 20 having a cylindrical portion 201 and a large diameter portion 202 formed at one end of the cylindrical portion 201 and extending radially outward from the cylindrical portion 201, a coil 21 wound around the cylindrical portion 201 of the bobbin 20, and a primary exterior body 22 covering an outer periphery of the coil 21 and a side surface 202a of the large diameter portion 202 of the bobbin 20 and constituting a seal portion 23 between the side surface 202a of the large diameter portion 202 of the bobbin 20 and the primary exterior body. From among both end surfaces 2021, 2022 of the large diameter portion 202, at least a portion of the end surface 2022 opposite to the side on which the coil 21 is wound is exposed from the primary exterior body 22.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a solenoid provided in a solenoid valve, a shock absorber, and a method for manufacturing the solenoid. [Background technology]

[0002] Patent Document 1 describes a molded coil in which a coil is wound between frame plates provided near both ends of a cylindrical coil bobbin made of thermoplastic resin, protrusions are formed on the outer and outer peripheral surfaces of the frame plate that continue in the circumferential direction and have thin-walled portions at their tips, and molten high-temperature resin of a molding material made of the same resin is injection molded onto the outer peripheral portion of the coil bobbin, so that the thin-walled portions are heated and melted by the molding material and the two are heat-fused together (see abstract). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 9-63835 Summary of the Invention [Problem to be solved by the invention]

[0004] The molded coil of Patent Document 1 has a structure in which the protrusions on the end face of the coil bobbin are melted, so that it is necessary to inject molding material onto the end face of the coil bobbin, and the molding material on the end face of the coil bobbin increases the axial length of the coil.

[0005] An object of the present invention is to provide a solenoid structure capable of shortening the axial length. [Means for solving the problem]

[0006] In order to achieve the above object, the solenoid of the present invention comprises: A solenoid mounted on a solenoid valve, The solenoid is a bobbin having a cylindrical portion and a large diameter portion formed at one end of the cylindrical portion and extending radially outward from the cylindrical portion; a coil wound around the cylindrical portion of the bobbin; a primary exterior body covering an outer periphery of the coil and a side surface of the large diameter portion of the bobbin and forming a seal portion between the primary exterior body and the side surface of the large diameter portion of the bobbin; having Of both end faces of the large diameter portion, at least a portion of the end face opposite the side on which the coil is wound is exposed from the primary exterior body. Effect of the Invention

[0007] According to the present invention, the axial length of the solenoid can be shortened by providing a seal on the side surface of the large diameter portion of the bobbin and eliminating the seal on the end surface of the large diameter portion. By shortening the axial length of the solenoid, it is possible to reduce the size of the shock absorber. Problems, configurations and effects other than those described above will become apparent from the following description of the preferred embodiment of the invention. [Brief description of the drawings]

[0008] [Figure 1] 1 is a vertical cross-sectional view of a solenoid according to an embodiment of the present invention. [Diagram 2] FIG. 2 is a vertical cross-sectional view showing a molded coil taken out from the solenoid of FIG. [Diagram 3] 3 is an enlarged view of the vicinity of the side surface of the large diameter portion of the molded coil (part III in FIG. 2). [Figure 4] FIG. 13 is a diagram showing a modified example (first modified example) of a solenoid according to the present invention, and is an enlarged view of the vicinity of the side surface of the large diameter portion of the molded coil. [Diagram 5] FIG. 13 is a diagram showing a modified example (second modified example) of the solenoid according to the present invention, and is an enlarged view of the vicinity of the side surface of the large diameter portion of the molded coil. [Figure 6] FIG. 4 is an enlarged view of the outer periphery of the molded coil. [Figure 7] 4 is an enlarged view of the vicinity of the outer periphery of the large diameter portion of the bobbin. FIG. [Figure 8]1 is an example of a vertical cross-sectional view of a molding die for a primary exterior body. [Figure 9] 1 is a vertical sectional view of a shock absorber according to the present invention; [Figure 10] FIG. 13 is an enlarged view of a side surface of a large diameter portion of a molded coil in a comparative example of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0010] First, a shock absorber to which the solenoid 1 according to the present invention is applied will be described with reference to Fig. 9. Fig. 9 is a vertical cross-sectional view of a shock absorber 100 according to the present invention. Note that in this embodiment, the shock absorber 100 with adjustable damping force will be described as an example.

[0011] The damping force control hydraulic shock absorber (hereinafter referred to as shock absorber) 100 according to this embodiment has a double cylinder structure in which an outer cylinder 103 is provided on the outside of a cylinder 102, and a reservoir 104 is formed between the cylinder 102 and the outer cylinder 103. A piston 105 is slidably fitted in the cylinder 102, and the inside of the cylinder 102 is divided into two chambers, a cylinder upper chamber 102A and a cylinder lower chamber 102B, by this piston 105. One end of a piston rod 106 is connected to the piston 105 by a nut 107, and the other end side of the piston rod 106 passes through the cylinder upper chamber 102A, is inserted through a rod guide 108 and an oil seal 109 attached to the upper end of the cylinder 102 and the outer cylinder 103, and is extended to the outside of the cylinder 102. A base valve 110 that divides the cylinder lower chamber 2B and the reservoir 104 is provided at the lower end of the cylinder 102.

[0012] Piston 105 is provided with oil passages 111 and 112 that communicate between upper and lower cylinder chambers 102A and 102B. Oil passage 111 is provided with a check valve 113 that allows oil to flow only from lower cylinder chamber 102B to upper cylinder chamber 102A, and oil passage 112 is provided with a disk valve 114 that opens when the pressure of the oil on the upper cylinder chamber 102A side reaches a predetermined pressure to relieve the oil on the upper cylinder chamber 102A side to the lower cylinder chamber 102B side.

[0013] The base valve 110 is provided with oil passages 115 and 116 that communicate between the cylinder lower chamber 102B and the reservoir 104. The oil passage 115 is provided with a check valve 117 that allows only the flow of oil from the reservoir 104 side to the cylinder lower chamber 102B side, and the oil passage 116 is provided with a disk valve 118 that opens when the pressure of the oil in the cylinder lower chamber 102B side reaches a predetermined pressure, thereby relieving the oil in the cylinder lower chamber 102B side to the reservoir 104 side. The oil is sealed in the cylinder 102, and the oil and gas are sealed in the reservoir 104.

[0014] A separator tube 120 is fitted to both upper and lower ends of the cylinder 102 via seal members 119, and an annular oil passage 121 is formed between the cylinder 102 and the separator tube 120. The annular oil passage 121 is connected to the cylinder upper chamber 102A by an oil passage 122 provided in the side wall near the upper end of the cylinder 102. A small-diameter opening 123 is provided in the side wall of the separator tube 120, and a large-diameter opening 124 is provided in the side wall of the outer cylinder 103 approximately concentrically with the opening 123, and a damping force generating mechanism 125 is attached to the opening 124 in the side wall of the outer cylinder 103.

[0015] The damping force adjustable shock absorber 100 is mounted, for example, on a suspension device of an automobile. In general, the damping force adjustable shock absorber 100 has a piston 105 connected to a piston rod 106 slidably fitted in a cylinder 102 filled with oil, dividing the cylinder 102 into two chambers, and generates a damping force by controlling the flow of oil caused by the sliding of the piston 105 in the cylinder 102 with a damping force generating mechanism 125 consisting of an orifice, a disk valve, etc., and adjusts the damping force by changing the flow resistance of the damping force generating mechanism 125 using a pressure control valve 128. The damping force generating mechanism 125 includes a solenoid 1 for controlling the pressure control valve 128, and constitutes an electromagnetic valve. Hereinafter, the damping force generating mechanism 125 will be described as an "electromagnetic valve."

[0016] The solenoid 1 according to the present invention will now be described. <Solenoid 1 structure> FIG. 1 is a vertical cross-sectional view of a solenoid 1 according to an embodiment of the present invention. In the following description, the "axial direction" refers to the direction along the central axis 20a of the bobbin 20, and the radial direction refers to the radial direction of the bobbin 20, i.e., the direction perpendicular to the central axis 20a. The bobbin 20 has a tube portion (cylindrical portion) 201 (see FIG. 2) as described below, and the central axis 20a is an axis passing through the center of the cylindrical portion 201.

[0017] The solenoid 1 is used to open and close a pressure control valve 128 of a damping force control shock absorber 100 that is mounted on a suspension device of a vehicle such as an automobile. The solenoid 1 includes a molded coil 2, a yoke 3, a housing 4, a cylinder 5, an armature 6, an anchor 7, a rod 8, and a bush 9. Reference numeral 10 denotes a plate provided at one end of the solenoid 1. When a current flows through the molded coil 2, the yoke 3, the housing 4, and the armature 6 are magnetized, and an attractive force is generated between the anchor 7 located at one end of the molded coil 2 and the armature 6. The rod 8 is fixed to the center of the armature 6, and the rod 8 is supported by the anchor 7 via the bush 9 so as to be capable of linear motion in the axial direction. When an attractive force is generated between the armature 6 and the anchor 7, a thrust is applied to the valve body of the pressure control valve 128 by the rod 8.

[0018] <Basic structure of molded coil 2> FIG. 2 is a vertical cross-sectional view showing the molded coil 2 taken out from the solenoid 1 of FIG. The molded coil 2 has a bobbin 20 consisting of a cylindrical portion 201 and a large diameter portion 202 extending radially outward from the cylindrical portion 201, a coil 21 with an insulating coating wound around the cylindrical portion 201 of the bobbin 20, and a primary exterior body 22 that covers the outer periphery of the coil 21 and a side surface 202a of the large diameter portion 202 of the bobbin 20. A seal portion 23 is formed between the primary exterior body 22 and the large diameter portion 202 of the bobbin 20, and the seal portion 23 is located on the side surface 202a of the large diameter portion 202. The primary exterior body 22 is formed by overmolding the bobbin 20 around which the coil 21 is wound, and the seal portion 23 is formed by melting the interface between the primary exterior body 22 and the bobbin 20.

[0019] Fig. 3 is an enlarged view of the vicinity of the large diameter portion side surface 202a (part III in Fig. 2) of the molded coil 2. Hereinafter, "end surface" refers to the end surface in the axial direction. The axial position of end face 221 of primary outer casing 22 differs from the axial position of end face 2022 opposite end face 2021 of large diameter portion 202 connected to tubular portion 201, and distance L1 between end face 221 of primary outer casing 22 and end face 2021 of large diameter portion 202 is greater than thickness T1 of large diameter portion 202. That is, end face 221 of primary outer casing 22 is located in an axial direction away from end face 2022 of large diameter portion 202 on the opposite side to coil 21. In this case, height H1 of seal portion 23 in the axial direction is equal to thickness T1 of large diameter portion 202.

[0020] Moreover, the entire end face 2022 of the large diameter portion 202 is exposed. Here, "exposed" means that it is not covered by the primary exterior body 22 but is exposed from the primary exterior body 22. In other words, the end face 2022 may be covered by the yoke 3 or the plate 10 as shown in FIG.

[0021] 1, since at least a portion of the end face 2022 is covered by other members such as the yoke 3 and the plate 10, it is sufficient that at least a portion of the end face 2022 is exposed from the primary exterior body 22 so that the axial length of the solenoid 1 can be shortened in relation to these other members. That is, of both end faces 2021, 2022 of the large diameter portion 202, the end face 2022 opposite to the side on which the coil 21 is wound is at least partially exposed from the primary exterior body 22.

[0022] FIG. 4 is a diagram showing a modified example (first modified example) of the solenoid 1 according to the present invention, and is an enlarged view of the vicinity of the large diameter portion side surface 202a of the molded coil 2. In FIG. In this example, the axial position of end face 221 of primary exterior body 22 coincides with the axial position of end face 2022 of large diameter portion 202. In this case, height H1 of seal portion 23 in the axial direction of bobbin 20 is equal to thickness T1 of large diameter portion 202. In this example, the axial length of molded coil 2 alone can be shortened compared to the case of Fig. 3, and the axial length of solenoid 1 can be reliably shortened.

[0023] FIG. 5 is a diagram showing a modified example (second modified example) of the solenoid 1 according to the present invention, and is an enlarged view of the vicinity of the large diameter portion side surface 202a of the molded coil 2. In FIG. In this example, distance L1 between end face 221 of primary outer casing 22 and end face 2021 of large diameter portion 202 is smaller than thickness T1 of large diameter portion 202. In this case, distance L1 between end face 221 and end face 2021 becomes height H1 of seal portion 23 in the axial direction, and height H1 of seal portion 23 is smaller than thickness T1 of large diameter portion 202. If the sealing performance of seal portion 23 can be ensured, distance L1 can be made smaller than thickness T1, and molded coil 2 can be made smaller in size.

[0024] In the above-described embodiment and modified example, the side surface 202a of the large diameter portion 202 of the bobbin 20 is shown to have a simple cylindrical shape, but the side surface 202a of the large diameter portion 202 does not necessarily have to be cylindrical. For example, the side surface 202a of the large diameter portion 202 may have a different shape, such as a protrusion.

[0025] As shown in FIGS. 3 to 5, in this embodiment and the modified example, the height H1 of the seal portion 23 in the axial direction is equal to or smaller than the thickness T1 of the large diameter portion 202.

[0026] <Structure of the coil periphery> FIG. 10 is an enlarged view of the large diameter portion side surface 202a of a molded coil in a comparative example to the present invention. In this embodiment, the seal portion 23 between the primary exterior body 22 and the bobbin 20 is located on the side surface 202a of the large diameter portion 202. On the other hand, in the comparative example to the present invention, as shown in Fig. 10, the primary exterior body 22 is also provided on the end surface 2022 of the large diameter portion, and the seal portion 23 is formed on the end surface 2022 of the large diameter portion 202 of the bobbin as well as on the side surface 202a of the large diameter portion 202 of the bobbin. For this reason, the area of ​​the seal portion 23 is larger than that of this embodiment.

[0027] In this embodiment, in order to ensure sufficient waterproof performance at the seal portion 23, the molding temperature during overmolding of the primary outer casing 22 is made higher than in the past, and the heat from the primary outer casing 22 reliably melts the resin material on the side surface 202a of the large diameter portion 202.

[0028] FIG. 6 is an enlarged view of the outer periphery of the molded coil 2. As shown in FIG. Protective means 24 is provided between primary exterior body 22 and coil 21. Protective means 24 is, for example, a sheet-like member. Hereinafter, protective means will be referred to as a protective member or protective section. If the molding temperature during overmolding of primary exterior body 22 is set lower than the melting point of protective section 24, protective section 24 will not liquefy during injection molding, and direct contact between primary exterior body 22 and coil 21 can be avoided. For this reason, a material with a melting point higher than the heat resistance temperature of the insulating coating of coil 21 is used for protective section 24.

[0029] Here, the heat resistance temperature of the insulating coating of coil 21 is the temperature at which the insulating performance of coil 21 deteriorates after overmolding of primary exterior body 22, and is equal to or lower than the melting point of the insulating coating of coil 21. By providing protective part 24 between primary exterior body 22 and coil 21, the molding temperature of primary exterior body 22 can be set to be equal to or higher than the heat resistance temperature of the insulating coating of coil 21, and primary exterior body 22 can be molded at a higher temperature than before.

[0030] In addition, it is preferable to use a material for protective part 24 whose thermal conductivity is lower than that of the insulating coating of coil 21. This makes it possible to reduce the amount of heat that transfers to coil 21 through protective part 24 during injection molding of primary exterior body 22.

[0031] FIG. 7 is an enlarged view of the vicinity of the outer periphery of the large diameter portion 202 of the bobbin 20. As shown in FIG. At the end face 2021 of the large diameter portion 202 of the molded coil 2, the diameter of the large diameter portion 202 is small, and a step (step portion) 2023 is formed in the large diameter portion 202. If there is a gap between the protective portion 24 and the large diameter portion 202, there is a risk that molten resin will flow into the outer periphery of the coil 21 during molding of the primary exterior body 22, damaging the insulating coating of the coil 21. However, by providing the step 2023, it becomes easy to position the protective portion 24 so that the protective portion 24 reliably covers the axial end of the winding range of the coil 21 when winding the protective portion 24 around the outer periphery of the coil 21, and it is possible to prevent a gap from being generated between the end face 2021 of the large diameter portion 202 and the protective portion 24. In this case, the large diameter portion 202 has the step 2023 at the end face 2021 on the winding side of the coil 21, and the protective portion 24 is provided so as to cover the step 2023.

[0032] 7, protective portion 24 is wound around the small diameter portion of step 2023, so seal portion 23 is not formed at step 2023. Therefore, it is desirable to minimize the height of step 2023 in order to prevent deterioration of the waterproof function of seal portion 23. Also, it is not always necessary to provide step 2023, and for example, if protective portion 24 is wound around the outer periphery of coil 21 using a device with high positioning accuracy, step 2023 does not always need to be provided.

[0033] In this embodiment, an example is shown in which a sheet-like member is used as protective portion 24, but other protective means, such as a sprayed coating agent or an overmolded resin layer, may also be used. Also, in this embodiment, an example is shown in which protective portion 24 is used, but in the case of a material with a small heat of fusion, such as syndiotactic polystyrene resin (SPS), even if the molding temperature of primary exterior body 22 is equal to or lower than the heat resistance temperature of the insulating coating of coil 21, sufficient waterproofing function can be imparted to seal portion 23, so protective portion 24 does not need to be provided.

[0034] <Waterproof performance of seal part 23> The waterproof performance of the seal portion 23 in this embodiment was verified using glass fiber reinforced nylon resin (PA66-GF30). For the bobbin 20 having a large diameter portion with a diameter of 28 mm and a thickness of 3 mm, a gate was provided near the side of the large diameter portion 202 of the bobbin 20 so that the temperature of the primary exterior body 22 would be 280°C or higher when it reached the large diameter portion 202 of the bobbin 20, and the bobbin 20 was overmolded. Then, the obtained molded coil 2 was subjected to a submersion test to confirm the presence or absence of leakage. As a result, it was confirmed that the leakage was blocked at the 1 mm thick portion of the large diameter portion side surface 202a, and the necessary waterproof function was ensured even if the seal portion between the primary exterior body 20 and the bobbin 20 was provided only on the large diameter portion side surface 202a.

[0035] A fluororesin sheet (thermal conductivity 0.25 Wm) having a thickness of 0.3 mm was attached to the outermost periphery of the bobbin 20 having a cylindrical portion 201 with a height of 12.5 mm as a protective portion 24. -1 .K -1 The temperature during molding when the insulating film 21 was wound around the coil 21 was determined by finite element analysis. When injection molding is performed with the gate set at half the height of the cylindrical portion 201, by setting the cylinder temperature to 295°C, the temperature when the primary exterior body 22 reaches the large diameter portion 202 is 280°C or higher and 295°C or lower, and the waterproof performance of the seal portion 23 can be ensured. In addition, since the melting point of the fluororesin sheet is 312°C, the protective portion 24 does not melt during injection molding, and the insulating coating of the coil 21 (heat-resistant temperature 290°C to 300°C) is not damaged.

[0036] The manufacturing method of the solenoid 1 of this embodiment is to provide a protective portion 24 on the outer peripheral surface of the coil 21, the protective portion 24 having a melting point higher than the heat resistance temperature of the insulating coating of the coil 21, heat the primary outer casing 22 to 280°C or higher, and injection mold the primary outer casing 22 so that the outer peripheral surface of the primary outer casing 22 and the side surface 202a of the large diameter portion 202 of the bobbin 20 are covered and the end face 2022 of the large diameter portion 202 is exposed.

[0037] <Molded coil manufacturing method> Next, an example of a manufacturing process for the molded coil 2 of the solenoid 1 will be described. In this embodiment, an example of using a glass fiber reinforced nylon resin (for example, PA66-GF30) will be described.

[0038] FIG. 8 is an example of a vertical cross-sectional view of a molding die 30 for the primary exterior body 22. As shown in FIG. The molding die 30 has restraining portions 301 on both axial ends, which restrict the flow of the primary exterior body 22 in the axial direction Ax during injection molding.

[0039] The protective part 24 is provided on the outer periphery of the bobbin 20 around which the coil 21 is wound before injection molding of the primary exterior body 22. Then, after the bobbin 20, the coil 21, and the protective part 24 are placed inside the molding die 30, the primary exterior body 22 is injected through the gate 302 to fill the inside of the molding die 30.

[0040] 8 shows an example in which the gate 302 is provided at one location on the molding die 30, and the gate 302 is desirably disposed at a half height position of the tubular portion 201 so that the time it takes for the resin forming the primary exterior body 22 to reach the two large diameter portions 202 in the axial direction Ax during injection molding is minimized. In the example shown in FIG. 8, the heating temperature in the cylinder is set to 295° C. or higher so that the temperature when the primary exterior body 22 reaches the large diameter portions 202 during injection molding is 280° C. or higher. In this embodiment, an example in which the gate 302 is provided at one location at half the height of the tubular portion 201 is shown, but the gate 302 does not necessarily have to be provided at half the height of the tubular portion 201, and a plurality of gates may be provided instead of one location.

[0041] <Action and effect> According to the embodiment and its modifications described above, the following advantages can be obtained.

[0042] Since the seal portion 23 of the molded coil 2 is located on the side surface 202a of the large diameter portion 202 of the bobbin 20, the end surface 2022 of the large diameter portion 202 is exposed. Therefore, the axial length of the molded coil 2 can be made shorter than that of the molded coil structure of the comparative example to the present invention shown in Fig. 10. As a result, the axial length of the housing 4 and the anchor 6 can be shortened, the axial length of the solenoid 1 can be shortened, and the potential valve 125 of the shock absorber 100 can be made smaller.

[0043] Furthermore, when the shapes of the housing 4 and the anchor 6 are maintained, the axial length of the cylindrical portion 201 of the bobbin 20 can be made longer than that of the molded coil structure of the comparative example of the present invention. As a result, the number of turns of the coil 21 can be increased, thereby increasing the attractive force of the armature 4 and the anchor 6 and increasing the thrust of the solenoid 1.

[0044] The above-described embodiment of the present invention has the following features. (1) A solenoid 1 mounted on an electromagnetic valve 125, Solenoid 1 is a bobbin 20 having a cylindrical portion 201 and a large diameter portion 202 formed at one end of the cylindrical portion 201 and extending radially outward from the cylindrical portion 201; A coil 21 wound around a cylindrical portion 201 of a bobbin 20; a primary exterior body 22 that covers an outer periphery of the coil 21 and a side surface 202a of the large diameter portion 202 of the bobbin 20 and forms a seal portion 23 between the primary exterior body 22 and the side surface 202a of the large diameter portion 202 of the bobbin 20; having Of both end faces 2021 , 2022 of large diameter portion 202 , end face 2022 opposite the side on which coil 21 is wound is at least partially exposed from primary exterior body 22 .

[0045] (2) The height H1 of the seal portion 23 in the axial direction of the bobbin 20 is equal to or smaller than the thickness T1 of the large diameter portion 202.

[0046] (3) Of both end faces 2021 , 2022 of large diameter portion 202 , end face 2022 opposite the side on which coil 21 is wound is entirely exposed from primary exterior body 22 .

[0047] (4) A protective portion 24 is provided between the outer circumferential surface of the coil 21 and the primary exterior body 22, The melting point of the protective portion 24 is higher than the heat-resistant temperature of the insulating coating of the coil 21 .

[0048] (5) The thermal conductivity of the protective portion 24 is smaller than the thermal conductivity of the insulating coating of the coil 21.

[0049] (7) A protective portion 24 is provided between the outer circumferential surface of the coil 21 and the primary exterior body 22, The protective portion 24 is made of a sheet-like material.

[0050] (7) The large diameter portion 202 has a step 2023 on an end surface 2021 on the winding side of the coil 21, The protective portion 24 is provided so as to cover the step 2023 .

[0051] (8) A shock absorber 100 that is mounted on a suspension device of an automobile and has a pressure control valve 128 and a solenoid for controlling the pressure control valve 128, The solenoid is a solenoid 1.

[0052] (9) A method for manufacturing a solenoid 1, comprising the steps of: A protective portion 24 having a melting point higher than the heat resistance temperature of the insulating coating of the coil 21 is provided on the outer circumferential surface of the coil 21, The primary exterior body 22 is heated to 280° C. or higher, Primary exterior body 22 is injection molded so as to cover the outer peripheral surface of primary exterior body 22 and side surface 202a of large diameter portion 202 of bobbin 20, and so as to expose end surface 202a of large diameter portion 202.

[0053] (10) A method for manufacturing a solenoid 1, comprising the steps of: The thermal conductivity of the protective portion 22 is smaller than the thermal conductivity of the insulating coating of the coil 21 .

[0054] The present invention is not limited to the above-mentioned embodiment, and other forms conceivable within the scope of the technical idea of ​​the present invention are also included within the scope of the present invention as long as they do not impair the characteristics of the present invention. The present invention is also not limited to the above-mentioned embodiment, and includes various modified examples. For example, the above-mentioned embodiment has been described in detail to explain the present invention in an easy-to-understand manner, and is not necessarily limited to those including all of the configurations. In addition, it is possible to add, delete, or replace part of the configuration of the embodiment with other configurations. [Explanation of symbols]

[0055] 1...solenoid, 20...bobbin, 21...coil, 22...primary outer casing, 23...sealing portion, 24...protective portion, 100...damping force adjustable shock absorber, 125...solenoid valve, 128...pressure control valve, 201...tubular portion, 202...large diameter portion, 202a...side surface of large diameter portion 202, 2021...end surface of winding side of coil 21, 2022...end surface opposite to the winding side of coil 21, 2023...step.

Claims

1. A solenoid mounted on a solenoid valve, The solenoid is a bobbin having a cylindrical portion and a large diameter portion formed at one end of the cylindrical portion and extending radially outward from the cylindrical portion; a coil wound around the cylindrical portion of the bobbin; a primary exterior body covering an outer periphery of the coil and a side surface of the large diameter portion of the bobbin and forming a seal between the primary exterior body and the side surface of the large diameter portion of the bobbin; having A solenoid in which at least a portion of one of the end faces of the large diameter portion opposite the side on which the coil is wound is exposed from the primary exterior body.

2. 2. The solenoid of claim 1, A solenoid, wherein the height of the seal portion in the axial direction of the bobbin is equal to or smaller than the thickness of the large diameter portion.

3. 2. The solenoid of claim 1, A solenoid in which one of the end faces of the large diameter portion opposite the side on which the coil is wound is entirely exposed from the primary exterior body.

4. 2. The solenoid of claim 1, a protective portion between an outer circumferential surface of the coil and the primary exterior body; The protective portion is a solenoid having a melting point higher than the heat resistance temperature of the insulating coating of the coil.

5. 5. A solenoid as claimed in claim 4, The protective portion is a solenoid having a thermal conductivity lower than that of the insulating coating.

6. 2. The solenoid of claim 1, a protective portion between an outer circumferential surface of the coil and the primary exterior body; The protective portion is a solenoid constituted by a sheet-like material.

7. 7. A solenoid as claimed in claim 6, the large diameter portion has a step on an end surface on a winding side of the coil, The protection portion is a solenoid provided to cover the step.

8. A shock absorber that is attached to a suspension device of an automobile and has a pressure control valve and a solenoid for controlling the pressure control valve, A shock absorber comprising the solenoid according to claim 1 as the solenoid.

9. A method for manufacturing the solenoid according to claim 1, comprising the steps of: a protective portion having a melting point higher than the heat resistance temperature of the insulating coating of the coil is provided on the outer circumferential surface of the coil; The primary outer casing is heated to 280° C. or higher, A method for manufacturing a solenoid, comprising injection molding the primary exterior body so as to cover an outer peripheral surface of the primary exterior body and a side surface of the large diameter portion of the bobbin, and to expose an end face of the large diameter portion.

10. A method for manufacturing a solenoid according to claim 9, comprising the steps of: A method for manufacturing a solenoid, wherein the protective portion has a thermal conductivity lower than that of the insulating coating.

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