Solenoid

Abstract

The purpose of the present invention is to provide a solenoid that achieves an improvement in waterproofness between a bobbin and an exterior body while achieving a reduction in size.　A solenoid 1 according to the present invention comprises: a bobbin 20 including a cylindrical part 201 and a large-diameter part 202 extending radially outward from the position of an axial end of the cylindrical part 201; a coil 21 wound around the cylindrical part 201 of the bobbin 20; an exterior body 22 covering the outer periphery of the coil 21 and the outer periphery of the large-diameter part 202, and forming a seal part 25 between the exterior body 22 and the large-diameter part 202; and an injection part 23 formed on the surface of the exterior body 22, the injection part 23 being an injection mark of a molding resin forming the exterior body 22. The large-diameter part 202 includes, in a part thereof including a portion farthest from the injection part 23, a shape-modified portion 203 having an axial thickness that is set to be greater than that of other portions.

Description

solenoid

[0001] The present invention relates to a solenoid used to open and close a control valve of a shock absorber.

[0002] Suspension devices for automobiles and other vehicles are equipped with adjustable damping shock absorbers, which adjust the damping force by opening and closing a control valve. A solenoid is used to open and close the control valve. The coil used in the solenoid is molded using molded resin to make it waterproof, forming a molded coil. When current flows through the molded coil, the housing, yoke, and armature that make up the magnetic circuit are magnetized, generating an attractive force between the axially movable armature and an anchor fixed to the end of the molded coil. This causes thrust to be applied to the valve element of the control valve by a rod fixed integrally with the armature.

[0003] Solenoids used in automobile shock absorbers are installed close to the ground and exposed to the outside. If water gets into the molded coil, the electrical resistance of the coil changes, causing the solenoid to malfunction. Therefore, ensuring waterproofness of the molded coil is a challenge in solenoid design.

[0004] As a means for solving this problem, Patent Document 1 discloses a structure in which an O-ring is provided upstream of the solenoid bobbin to provide a seal, and Patent Document 2 discloses a structure in which protrusions with thinned portions are formed on both ends of the coil bobbin, and the molding resin and the coil bobbin are thermally welded together during molding to provide a seal.

[0005] Patent No. 5463684 Japanese Patent Application Publication No. 9-63835

[0006] In Patent Document 1, an O-ring groove for accommodating an O-ring is formed, which increases the axial length of the core, resulting in a problem in that the axial length of the entire control valve increases.

[0007] Furthermore, in Patent Document 2, a structure is adopted in which a protrusion provided on the end face of the coil bobbin is melted to seal the gap between the coil bobbin and the exterior body composed of the molded resin without using an O-ring. However, in Patent Document 2, because heat is transferred to the mold and coil bobbin as the molded resin moves, the temperature of the molded resin becomes lower at positions away from the injection port, leaving unmelted portions, which results in a problem of poor waterproofing between the coil bobbin and the exterior body.

[0008] An object of the present invention is to provide a solenoid that is compact and has improved waterproofing of the bobbin and exterior body.

[0009] In order to achieve the above object, the present invention provides a solenoid for use in a control valve, comprising: a bobbin composed of a cylindrical portion and a large diameter portion extending radially outward from the axial end position of the cylindrical portion; a coil wound around the cylindrical portion of the bobbin; an outer casing that covers the outer periphery of the coil and the outer periphery of the large diameter portion and forms a sealing portion between itself and the large diameter portion; and an injection portion formed on the surface of the outer casing and that serves as an injection mark for the molded resin that forms the outer casing, wherein the large diameter portion has a shape-changing portion whose axial thickness is set thicker in a portion including the portion farthest from the injection portion than in other portions.

[0010] According to the present invention, it is possible to provide a solenoid that is miniaturized and has improved waterproofing of the bobbin and the exterior body.

[0011] 1. A longitudinal sectional view of a solenoid 1. A longitudinal sectional view of a molded coil 2 according to an embodiment of the present invention. A top view of a bobbin 20 according to a first embodiment of the present invention, as seen from above. An external perspective view of the bobbin 20 according to the first embodiment of the present invention. An external perspective view of the bobbin 20 of FIG. 4 after overmolding. A sectional view taken along line VI-VI of FIG. 5. A top view of a bobbin 20 according to a first modified example, as seen from above. An external perspective view of the bobbin 20 according to the first modified example. An external perspective view of the bobbin 20 of FIG. 8 after overmolding. A sectional view taken along line X-X of FIG. 9. A sectional view taken along line XI-XI of FIG. 10. A top view of a bobbin 20 according to a second modified example, as seen from above. An external perspective view of the bobbin 20 according to the second modified example. An external perspective view of the bobbin 20 of FIG. 13 after overmolding. A sectional view taken along line XV-XV of FIG. 14. A top view of a bobbin 20 according to a second embodiment of the present invention, as seen from above. A top view of a bobbin 20 according to a third embodiment of the present invention, as seen from above. An external perspective view of the bobbin 20 according to the third embodiment of the present invention. Fig. 19 is an external perspective view of the bobbin 20 of Fig. 18 after overmolding. Fig. 20 is a cross-sectional view taken along the line XX-XX of Fig. 19. Fig. 21 is an enlarged view of a shape-changing portion 203 and other portions.

[0012] Hereinafter, embodiments of the present invention will be described with reference to the drawings. In principle, identical elements are designated by the same reference numerals in all drawings. Furthermore, descriptions of parts having identical functions will be omitted. Note that the configurations described below are merely examples, and it is not intended that the embodiments of the present invention be limited to the specific embodiments below.

[0013] In the following embodiment, for convenience, the upper side of the paper is defined as "upper" and the lower side of the paper is defined as "lower." In addition, in the present embodiment, the direction along the rod 8 is defined as the "axial direction," the rotation direction around this axial direction is defined as the "circumferential direction," and the direction perpendicular to the axial direction is defined as the "radial direction."

[0014] <Solenoid Structure> Figure 1 is a vertical cross-sectional view of a solenoid 1. The solenoid 1 is used to open and close a control valve of a damping force adjustable shock absorber attached to a suspension device of a vehicle such as an automobile. The solenoid 1 comprises a molded coil 2, a yoke 3, a housing 4, a cylinder 5, an armature 6, an anchor 7, a rod 8, a bushing 9, and a plate 10. C in the figure indicates the center line.

[0015] The yoke 3 is cylindrically formed from a magnetic material and arranged to cover the periphery of the molded coil 2. The housing 4 is also made of a magnetic material, is located on the inner periphery of the molded coil 2, and is arranged to cover one axial side of the armature 6. The cylinder 5 is cylindrically formed from a non-magnetic material and is arranged to extend axially from the upper surface of the bottom side of the yoke 3. The armature 6 is made of a magnetic material and fixed to a rod 8. The anchor 7 is cylindrically formed from a magnetic material and is located radially inward of the molded coil 2 and is arranged to cover the other axial side of the armature 6. A through hole communicating in the vertical direction (axial direction) is formed in the center of the anchor 7, and the rod 8 is inserted into this through hole. A bushing 9 is arranged below the through hole of the anchor 7.

[0016] When a current flows through the molded coil 2, the yoke 3, housing 4, and armature 6 are magnetized, and an attractive force is generated between the armature 6 and an anchor 7 located at the end of the molded coil 2. A rod 8 is fixed to the center of the armature 6, and the rod 8 is held via a bushing 9 so that it can move linearly in the axial direction. When an attractive force is generated between the armature 6 and the anchor 7, the rod 8 applies thrust to the valve disc of the control valve.

[0017] <Basic Structure of Molded Coil in This Example> Figure 2 is a longitudinal cross-sectional view of a molded coil 2 according to this example. As shown in Figure 2, the molded coil 2 includes a bobbin 20 including a cylindrical portion 201 and large-diameter portions 202 that extend radially outward from the axial ends of the cylindrical portion 201 (both axial ends in this example) and have a larger diameter than the cylindrical portion 201, an insulating-coated coil 21 wound around the cylindrical portion 201 of the bobbin 20, an outer casing 22 that coats the outer periphery of the coil 21 and the outer periphery of the large-diameter portion 202 of the bobbin 20 with mold resin, and an injection portion 23 that is formed on the surface of the outer casing 22 and has a rough surface.

[0018] A connecting portion 24 is provided in a part of the large diameter portion 202 (one side in FIG. 2 ), extending radially outward from the large diameter portion 202 and for connecting the coil 21 to an external terminal. The large diameter portion 202 and the connecting portion are formed continuously and integrally.

[0019] A seal portion 25 is formed between the exterior body 22 and the large diameter portion 202 of the bobbin 20, and the seal portion 25 is located on the end face or side face of the large diameter portion 202. The exterior body 22 is formed by overmolding the bobbin 20 around which the coil 21 is wound with a molding resin. In other words, the molded coil 2 is formed by overmolding the bobbin 20 around which the coil 21 is wound with a molding resin.

[0020] The injection portion 23 formed on the surface of the exterior body 22 is an injection mark of the molten molding resin that constitutes the exterior body 22. The seal portion 25 is formed by melting the interface between the exterior body 22 and the bobbin 20.

[0021] <Structure of the large diameter portion in the first embodiment> Fig. 3 is a top view of the bobbin 20 according to the first embodiment of the present invention. Fig. 4 is an external perspective view of the bobbin 20 according to the first embodiment of the present invention. Fig. 5 is an external perspective view of the bobbin 20 of Fig. 4 after overmolding. Fig. 6 is a cross-sectional view taken along line VI-VI in Fig. 5. Triangles in Figs. 3 and 4 indicate injection portions 23 (injection positions) for the molding resin.

[0022] 3 and 4 , a shape-changing portion 203 that protrudes upward from the surface (top surface) of the large diameter portion 202 is formed in a part of the large diameter portion 202 of the bobbin 20. The shape-changing portion 203 is formed so that a part of it protrudes from the circumferential surface of the large diameter portion 202.

[0023] In this embodiment, the shape-changing portion 203 is located on the opposite side of the mold resin injection portion 23 in the axial direction (vertical direction). In other words, the shape-changing portion 203 is provided at the position farthest from the injection portion 23 in the radial direction.

[0024] In this embodiment, the large diameter portion 202 includes a shape-changing portion 203 in a part including the part farthest from the injection portion 23, and the shape-changing portion 203 is set to have a thicker axial thickness at a predetermined radial position of the large diameter portion 202 than other parts.

[0025] Furthermore, the shape-changing portion 203 of this embodiment is connected to the connecting portion 24. That is, the connecting portion 24 is formed on an extension of the shape-changing portion 203 on the radially outer side.

[0026] Because the terminal wires of the coil 21 are arranged in two locations near the side of the connecting portion 24, the side of the connecting portion 24 is a thick portion that is thicker in the vertical direction than the large diameter portion 202. The upper surface of the shape-changing portion 203 that is connected to the connecting portion 24 is formed flush with the upper surface (front surface) of the connecting portion 24. The connecting portion 24 of this embodiment also serves as the shape-changing portion 203. As a result, when viewed from the side, the connecting portion 24 and the shape-changing portion 203 are thick portions that are thicker in the vertical direction than the large diameter portion 202. In other words, when viewed from the side, the large diameter portion 202 excluding the shape-changing portion 203 is a thin portion that is thinner in the vertical direction than the connecting portion 24 and the shape-changing portion 203.

[0027] In this embodiment, the shape-changing portion 203 is located on the opposite side of the mold resin injection portion 23 in the axial direction (vertical direction). In other words, the shape-changing portion 203 is provided at the position farthest from the injection portion 23 in the radial direction.

[0028] To manufacture the molded coil 2, a molding die is attached so as to cover the outer periphery of the bobbin 20 around which the coil 21 is wound, and molding resin (resin) is injected into the molding die from the injection portion 23 to overmold the bobbin 20. The molding die is then removed and the overmolded molded coil 2 is taken out. The molded coil 2 taken out of the molding die then looks like that shown in Figure 5.

[0029] The temperature of the molding resin injected into the molding die is highest near the injection portion 23 and tends to decrease with increasing distance from the injection portion 23. This is because the molding resin injected into the molding die loses temperature when it comes into contact with the molding die and the bobbin 20. This causes a problem in that the temperature of the molding resin decreases at positions away from the injection portion 23, leaving unmelted parts in the molding resin, which deteriorates the waterproof function with the bobbin 20. In order to improve the waterproof function at positions away from the injection portion 23, it is necessary to suppress the decrease in temperature of the molding resin at positions away from the injection portion 23 and suppress the unmelted parts of the molding resin.

[0030] The temperature of the molding resin injected into the molding die tends to be lower in the areas in contact with the molding die and the bobbin 20, and higher in the center, which is located away from the die and the bobbin 20. In other words, the temperature drop of the molding resin can be suppressed by increasing the cross-sectional area of ​​the flow path through which the molding resin flows. This embodiment focuses on this point.

[0031] In this embodiment, by setting the thickness at a predetermined radial position in the shape-changing portion 203 to be thicker than other portions as shown in Figure 6, the flow path of the outer casing 22 during overmolding becomes wider than the shape-changing portion 203, thereby improving the heat retention until the outer casing 22 reaches the shape-changing portion 203.

[0032] Furthermore, the temperature of the molded resin constituting exterior body 22 drops on the surface side due to contact between bobbin 20 and the molding die during overmolding, with the temperature near the center being the highest. Because shape-changing portion 203 is thicker than other portions, when exterior body 22 reaches shape-changing portion 203, the flow on the surface side of exterior body 22 is blocked, and the high-temperature portion of exterior body 22 away from the surface flows and comes into contact with the surface of large-diameter portion 202 in shape-changing portion 203. This causes the surface temperature of large-diameter portion 202 to increase at the position where shape-changing portion 203 is located.

[0033] According to this embodiment, by arranging shape-changing portion 203 in a portion including the position farthest from injection portion 23, the surface temperature of large-diameter portion 202 can be raised at a position where the temperature of the exterior body is lowest and where an unmelted portion is likely to remain on the surface of large-diameter portion 202, thereby more reliably melting the surface of large-diameter portion 202. As a result, the interface between the exterior body and large-diameter portion can be tightly sealed all around the circumference of large-diameter portion 202, enhancing the waterproof function of the solenoid. In particular, waterproof function can be sufficiently ensured even at seal portion 25 located on the end face or side of large-diameter portion 202.

[0034] [Modification 1] Next, Modification 1 of Example 1 will be described with reference to Figures 7 to 11. Figure 7 is a top view of the bobbin 20 according to Modification 1 as seen from above. Figure 8 is an external perspective view of the bobbin 20 according to Modification 1. Figure 9 is an external perspective view of the bobbin 20 of Figure 8 after overmolding. Figure 10 is a cross-sectional view taken along line X-X in Figure 9. Figure 11 is a cross-sectional view taken along line XI-XI in Figure 10. The same components as those in Example 1 are designated by the same reference numerals, and detailed description thereof will be omitted.

[0035] In the first modification, the position of the shape-changing portion 203 is on the opposite side of the connecting portion 24 , and a part of the injection portion 23 for the molding resin is provided at the position of the connecting portion 24 .

[0036] The bobbin 20 of the first modification has a groove 24a formed in the center of the connection portion 24, recessed from the upper surface (surface) of the connection portion 24. The groove 24a is a thin portion that is thin in the vertical direction (axial direction), and the dam portions 24b formed on both sides of the groove 24a are thick portions that are thicker in the vertical direction than the groove 24a. The wire terminal of the coil 21 is disposed in the thick dam portions 24b.

[0037] The large diameter portion 202 has an inner circumferential portion 202a and an outer circumferential portion 202b located radially outside the inner circumferential portion 202a, and the inner circumferential portion 202a is a thin-walled portion that is thin in the vertical direction (axial direction), while the outer circumferential portion 202b of the large diameter portion 202 is a thick-walled portion that is thicker in the vertical direction (axial direction) than the inner circumferential portion 202a.

[0038] The groove 24a of the connecting portion 24 is connected to the inner periphery 202a of the large diameter portion 202, and a shape-changing portion 203 is formed at the end of the inner periphery 202a located on the radially opposite side of the connecting portion 24. As shown in Figure 11, the shape-changing portion 203 has a stepped shape in the large diameter portion 202.

[0039] A portion of the molding resin injected from the molding die is injected toward groove 24a. The molding resin injected from groove 24a flows toward inner periphery 202a and reaches the opposite side of injection portion 23. Injection portion 23 is provided on the surface of exterior body 22 located on the radially outer extension of groove 24a. The molding resin flowing through groove 24a and inner periphery 202a flows at a faster rate than in the configuration of Example 1, so it is possible to allow the molding resin to reach the opposite side of injection portion 23 while suppressing a decrease in temperature. As a result, the interface between the exterior body and large diameter portion can be strongly sealed around the entire circumference of large diameter portion 202, enhancing the waterproof function of the solenoid.

[0040] [Modification 2] Next, Modification 2 of Example 1 will be described with reference to Figures 12 to 15. Figure 12 is a top view of the bobbin 20 according to Modification 2 as seen from above. Figure 13 is an external perspective view of the bobbin 20 according to Modification 2. Figure 14 is an external perspective view of the bobbin 20 of Figure 13 after overmolding. Figure 15 is a cross-sectional view taken along line XV-XV of Figure 14. The same components as those in Example 1 are designated by the same reference numerals, and detailed description thereof will be omitted.

[0041] In the second modification, the position of the shape-changing portion 203 is aligned with the connecting portion 24 .

[0042] In variant example 2, the large diameter portion 202 has an inner peripheral portion 202a and an outer peripheral portion 202b located radially outside the inner peripheral portion 202a, and the inner peripheral portion 202a is a thick-walled portion that is thicker in the vertical direction (axial direction), while the outer peripheral portion 202b of the large diameter portion 202 is a thin-walled portion that is thinner in the vertical direction (axial direction) than the inner peripheral portion 202a.

[0043] Outer periphery portion 202b is provided with shape-changing portion 203 that is set to be thicker in the axial direction than outer periphery portion 202b, and shape-changing portion 203 is connected to inner periphery portion 202a of large diameter portion 202 and connecting portion 24. The upper surface of shape-changing portion 203 is flush with the upper surface of connecting portion 24 and the upper surface of inner periphery portion 202a of large diameter portion 202.

[0044] The molding resin is injected from the radially opposite side of the connection portion 24. A portion of the molding resin injected from the groove 24a flows along the outer periphery 202b and reaches the connection portion 24 side, which is the opposite side of the injection portion 23. The molding resin flowing through the outer periphery 202b has a narrower flow path and a faster flow rate than in the configuration of Example 1, so it can reach the connection portion 24 side, which is the opposite side of the injection portion 23, while suppressing a decrease in the temperature of the molding resin. Furthermore, in Variation 2, the amount of molding resin injected into the exterior body 22 is reduced, shortening the molding time in the overmolding process and suppressing a decrease in the temperature of the molding resin. As a result, the interface between the exterior body 22 and the large diameter portion 202 can be strongly sealed around the entire circumference of the large diameter portion, thereby enhancing the waterproof function of the solenoid.

[0045] In Example 1 and Modifications 1 and 2, two injection portions 23 for the molding resin are provided in the height direction, and are arranged at the same height as the large diameter portion 202. The number of injection portions 23 does not necessarily have to be two; they may be arranged in three or more positions in the height direction, or in only one position. However, if too many injection portions 23 are arranged, weld lines formed by the union of the exterior body 22 during overmolding can cause a decrease in strength, so it is desirable to arrange the injection portions 23 in two or fewer positions. Furthermore, to ensure uniform flow of the exterior body 22 in the vertical direction of the bobbin 20 during overmolding, it is desirable to arrange the injection portions 23 symmetrically in the vertical direction.

[0046] <Effects of Example 1> For bobbins 20 having a cylindrical portion 201 with a height of 12.5 mm, the surface temperature of large diameter portion 202 when the mold resin constituting exterior body 22 reaches the opposite side of injection portion 23 was obtained by thermal fluid analysis for bobbins 20 having no shape-changing portion 203 in large diameter portion 202 and bobbins 20 having shape-changing portion 203 in large diameter portion 202. For bobbins 20 having shape-changing portion 203 in large diameter portion 202, the one in Modification 2 was used, and outer circumferential portion 202b of large diameter portion 202 was made 2 mm thinner than inner circumferential portion 202a and connection portion 24.

[0047] In the case where the outer periphery of the large diameter portion 202 is thinned except for the connection portion 24, the surface temperature of the large diameter portion 202 when the outer casing 22 reaches the opposite side of the injection portion 23 is 8°C higher than in the case where the shape-changing portion 203 is not present in the large diameter portion 202, and the large diameter portion 202 can be heated to a high temperature at the position farthest from the injection portion 23.

[0048] Note that, because the thickness of shape-changing section 203 at a predetermined radial position is smaller than that of other sections, the flow path of exterior body 22 becomes narrower. Therefore, the amount of temperature drop of exterior body 22 when flowing through shape-changing section 203 is larger than that of other sections, and the circumferential length of shape-changing section 203 needs to be set so that the temperature when exterior body 22 reaches the farthest position from injection section 23 is higher than in a configuration without shape-changing section 203.

[0049] The circumferential length of the shape-changing section 203 can be set, for example, by determining the amount of temperature drop when the outer casing 22 reaches the farthest position from the injection section 23 using thermal fluid analysis for a configuration without the shape-changing section 203 and a configuration in which the circumferential length of the shape-changing section 203 is changed in multiple patterns, and selecting the circumferential length that reduces the amount of temperature drop when the outer casing 22 reaches the farthest position from the injection section 23 compared to the configuration without the shape-changing section 203.

[0050] Alternatively, without performing analysis, for example, the integrated value Q of the amount of heat transferred from the exterior body 22 to the bobbin 20 and the molding die during overmolding may be calculated, and the circumferential length of the shape-changing portion 203 may be determined so that the integrated value Q of the amount of heat transferred exceeds that of a configuration without the shape-changing portion 203. The integrated value Q of the amount of heat transferred is calculated, for example, by performing a theoretical calculation based on the amount of heat transferred q. The integrated value Q of the amount of heat transferred is the amount of heat lost by the mold resin (resin). The theoretical calculation will be described below.

[0051] The amount of heat transfer q can be calculated according to the shape of the flow path in the exterior body 22 using the following equation 1.

[0052] q = (T mold -T ｄｉｅ ) / R ｄｉｅ + (T mold -T bobbin ) / R bobbin ...(Equation 1) where T mold is the temperature of the exterior body 22, T ｄｉｅ is the temperature of the molding die, T bobbin is the temperature of the bobbin 20. ｄｉｅ and R bobbin are the thermal resistances between the molding die and the bobbin 20, and the narrower the flow path of the exterior body 22, the smaller the thermal resistance R ｄｉｅ and the thermal resistance R of the bobbin 20 bobbin becomes smaller.

[0053] Thermal resistance R of the molding die ｄｉｅ and the thermal resistance R of the bobbin 20 bobbin is equal to and can be calculated by the following equation 2.

[0054] R ｄｉｅ =R bobbin = h / (S × λ ｍｏｌｄ) ... (Equation 2) where h is the thickness of the flow path, S is the contact area, λ ｍｏｌｄ is the thermal conductivity of the molding resin.

[0055] The integrated value Q of the heat transfer amount can be calculated by the following equation 3.

[0056] Q = ΣqΔt ≒ q ｎ t ｎ +q ｖ t ｖ ...(Equation 3) where q ｎ is the amount of heat transfer other than the shape-changing portion 203, q ｖ is the amount of heat transfer in the shape-changing portion 203, t ｎ is the time it takes to pass through the area other than the shape-changing area 203, and t ｖ is the time it takes for the shape-changing portion 203 to pass through.

[0057] The integrated value Q of the heat transfer amount can also be calculated using the following equation 4.

[0058] Q = ΣqΔt ≒ (q ｎ l ｎ +q ｖ l ｖ ) / V mold ...(Equation 4) where V mold is the flow rate of the molding compound (assumed to be constant), l ｎ is the length other than the shape change part, l ｖ is the length of the shape-changing portion 203.

[0059] Then, from the relationship between Equation 3 and Equation 4, the length l of the shape-changing portion 203 is ｖ can be obtained.

[0060] Next, a second embodiment of the present invention will be described with reference to Fig. 16. Fig. 16 is a top view of a bobbin 20 according to the second embodiment of the present invention, as viewed from above.

[0061] Large diameter portion 202 is provided with two shape-changing portions 203 that are set to have a thicker axial thickness than the other portions (large diameter portion 202) at positions on center line P that passes through the radial center of bobbin 20 and that are point-symmetric with respect to the central axis of bobbin 20. One shape-changing portion 203 is connected to connecting portion 24, and connecting portion 24 is set to have a thicker axial thickness than large diameter portion 202. In other words, connecting portion 24, together with one shape-changing portion 203, also serves as shape-changing portion 203.

[0062] The injection parts 23 are arranged on an orthogonal line P′ perpendicular to the center line P in the radial direction, and at positions that are point-symmetric with respect to the center axis of the bobbin 20 .

[0063] Each of the injection parts 23 arranged in point symmetry with respect to the central axis of the bobbin 20 is located at a position furthest from the shape-changing part 203 and the connection part 24 that also serves as the shape-changing part 203 .

[0064] In this embodiment, the injection portions 23 are disposed at two locations in the circumferential direction, but they may be disposed at three or more locations in the circumferential direction. In this case, too, the thickened portions of the large diameter portion 202 (the connection portion 24 and the shape-changing portion 203) are disposed at the positions farthest from the injection portions 23.

[0065] According to this embodiment, injection portion 23 is disposed symmetrically in a direction perpendicular (90 degrees) to center line P passing through the radial center of bobbin 20, which shortens the time it takes for molding resin injected from injection portion 23 to reach the thick portions of large diameter portion 202 (connection portion 24 and shape-changing portion 203), thereby suppressing a decrease in temperature of the molding resin. As a result, the interface between exterior body 22 and large diameter portion 202 can be tightly sealed all around the periphery, enhancing the waterproof function of the solenoid.

[0066] Next, a third embodiment of the present invention will be described with reference to FIGS. 17 to 21. FIG. 17 is a top view of a bobbin 20 according to the third embodiment of the present invention, as viewed from above. FIG. 18 is an external perspective view of the bobbin 20 according to the third embodiment of the present invention. FIG. 19 is an external perspective view of the bobbin 20 of FIG. 18 after overmolding. FIG. 20 is a cross-sectional view taken along line XX-XX in FIG. 19. FIG. 21 is an enlarged view of the shape-changing portion 203 and other portions. FIG. 21(a) shows the shape-changing portion 203, and FIG. 21(b) shows the portions other than the shape-changing portion 203. The same components as those in the first embodiment are designated by the same reference numerals, and detailed descriptions thereof will be omitted.

[0067] 17 and 18 , the large diameter portions 202 are not continuous with the connecting portions 24 and are thin-walled. The outer peripheries of the large diameter portions 202 are tapered. In this embodiment, a shape-changing portion 203 is provided in a part of the large diameter portion 202, where the taper angle θ is formed to be larger than the taper angle θ with the other large diameter portions 202.

[0068] In the shape-changing portion 203, the taper angle θ of the outer periphery is formed to be larger than that of the other portions, and the axial thickness AT at a predetermined radial position RL is set to be thicker than that of the other portions.

[0069] According to this embodiment, the tapered angle θ of the outer periphery is made different between the shape-changing portion 203 and the other portions, so that in addition to the effects of the first and second embodiments, the shape of the bobbin 20 can be simplified.

[0070] The present invention is not limited to the above-described embodiments, but includes various modifications. For example, the above-described embodiments have been described in detail to clearly explain the present invention, and the present invention is not necessarily limited to those including all of the described configurations. Furthermore, it is possible to replace part of the configuration of one embodiment with the configuration of another embodiment, or to add the configuration of another embodiment to the configuration of one embodiment. Furthermore, it is possible to add, delete, or replace part of the configuration of each embodiment with other configurations.

[0071] DESCRIPTION OF SYMBOLS 1... solenoid, 2... molded coil, 3... yoke, 4... housing, 5... cylinder, 6... armature, 7... anchor, 8... rod, 9... bushing, 10... plate, 20... bobbin, 21... coil, 22... outer casing, 23... injection portion, 24... connection portion, 24a... groove portion, 24b... dam portion, 25... seal portion, 201... cylindrical portion, 202... large diameter portion, 202a... inner peripheral portion, 202b... outer peripheral portion, 203... shape-changing portion

Claims

A solenoid used in a control valve, a bobbin including a cylindrical portion and a large diameter portion extending radially outward from an axial end of the cylindrical portion; a coil wound around the cylindrical portion of the bobbin; an exterior body that covers an outer periphery of the coil and an outer periphery of the large diameter portion and forms a seal between the exterior body and the large diameter portion; an injection portion formed on the surface of the exterior body, which serves as an injection mark for the molding resin that constitutes the exterior body; The solenoid is characterized in that the large diameter portion has a shape-changing portion whose thickness in the axial direction is set thicker in a part including the part farthest from the injection portion than in other parts.

2. The solenoid of claim 1, The solenoid is characterized in that the shape-changing portion has a stepped shape.

2. The solenoid of claim 1, a connection portion that connects the coil and an external terminal; The solenoid is characterized in that the connecting portion is connected to the shape-changing portion.

4. The solenoid of claim 3, The solenoid is characterized in that the connection portion is located radially outward of the shape-changing portion and is formed flush with the surface of the shape-changing portion.

2. The solenoid of claim 1, The solenoid is characterized in that the injection section is provided in a plurality in the axial direction of the exterior body.

2. The solenoid of claim 1, the large diameter portion includes an inner circumferential portion and an outer circumferential portion located radially outward of the inner circumferential portion and having a thickness in the axial direction greater than that of the inner circumferential portion, The solenoid is characterized in that the inner peripheral portion is provided with the shape-changing portion that is set to have a thickness in the axial direction greater than that of the inner peripheral portion.

7. The solenoid of claim 6, a connecting portion for connecting the coil and an external terminal to the radially outer side of the large diameter portion; the connection portion includes a groove portion formed in a central portion and recessed from a surface of the connection portion, and dam portions formed to sandwich the groove portion and having a thickness in the axial direction greater than that of the groove portion, The groove portion communicates with the inner circumferential portion of the large diameter portion, and the injection portion is provided on the surface of the outer casing located on an extension of the groove portion radially outward.

2. The solenoid of claim 1, the large diameter portion includes an inner circumferential portion and an outer circumferential portion located radially outward of the inner circumferential portion and having a thickness in the axial direction thinner than that of the inner circumferential portion, The solenoid is characterized in that the outer circumferential portion is provided with the shape-changing portion that is set to have a thickness in the axial direction greater than that of the outer circumferential portion.

9. The solenoid of claim 8, a connection portion that connects the coil and an external terminal; The solenoid is characterized in that the connecting portion is connected to the shape-changing portion.

2. The solenoid of claim 1, the large diameter portion includes two shape change portions at positions on a center line passing through a radial center of the bobbin and point-symmetric with respect to a central axis of the bobbin, The solenoid is characterized in that the injection portions are arranged on an orthogonal line perpendicular to the center line in a radial direction and at positions that are point-symmetric with respect to the central axis of the bobbin.

11. The solenoid of claim 10, a connection portion that connects the coil and an external terminal; The connecting portion has an axial thickness set to be thicker than that of the large diameter portion, and is connected to one of the two shape-changing portions.

2. The solenoid of claim 1, The outer periphery of the large diameter portion is formed in a tapered shape, The shape-changing portion is formed so that a taper angle in a part of the large diameter portion is larger than a taper angle with the other large diameter portion, The solenoid is characterized in that the axial thickness of the shape-changing portion at a predetermined radial position is set to be thicker than that of other portions.

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