Solenoid actuator and method for manufacturing a solenoid actuator

Abstract

To provide a solenoid actuator which is excellent in suction characteristics and can be manufactured at low costs, and to provide a method of manufacturing the solenoid actuator.SOLUTION: A solenoid actuator 1 (1A, 1B) includes: a coil 3; a first stator 10 and a second stator 20 which are arranged forming an air gap 11 therebetween in an axial direction so as to form a magnetic path 4 around the coil 3; and a movable element 50 configured to move in the axial direction toward the second stator 20 from an original position radially inward of the first stator 10 by a magnetic force generated by energizing the coil 3. The first stator 10 includes: a first yoke 14; and a first cylindrical member 30 which is fixed to the inner periphery side of the first yoke 14 and forms the air gap 11.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present disclosure relates to a solenoid actuator and a method for manufacturing the solenoid actuator.

Background Art

[0002] Conventionally, a solenoid actuator has been known in which a stator that forms a magnetic path around a coil is arranged, and a mover is attracted by a magnetic force generated by energizing the coil, so that the mover can be moved in the axial direction.

[0003] For example, Patent Document 1 describes an electromagnetic actuator including a first stator provided on the stroke start position (original position) side of a mover and a second stator provided on the stroke end position side of the mover. In the electromagnetic actuator described in Patent Document 1, in order to realize a flat attraction characteristic over the entire stroke length of the mover, the outer shapes of the mover and the first stator are devised. Specifically, as the mover moves toward the stroke end position side, a tapered portion that narrows the gap between the first stator and the mover is provided on the outer peripheral surface of the mover. On the other hand, a convex curved surface that widens the gap between the first stator and the mover is provided at the end of the first stator on the second stator side.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] Incidentally, the suction characteristics of a solenoid actuator are affected not only by the gap between the stator and the movable part, but also by the air gap between the first stator and the second stator. Therefore, in order to achieve the desired suction characteristics of the solenoid actuator, it is desirable to control the air gap between the first stator and the second stator with high precision.

[0006] However, if there are many related parts that determine the size of the air gap, then trying to control the air gap between the first and second stators with high precision will require stricter tolerances for each part, which will increase the manufacturing cost of the solenoid actuator. For example, in the electromagnetic actuator described in Patent Document 1, the first stator is fixed to the base, and the second stator (cover member) is fixed to the case. Therefore, the air gap between the first stator and the second stator is affected by the axial dimensions of the first and second stators themselves, and the axial dimensions of the base and the case. In the electromagnetic actuator described in Patent Document 1, the relevant parts that determine the size of the air gap are the first stator, the second stator, the base, and the case, and in order to control the air gap with high precision, it is necessary to reduce the dimensional tolerances of these parts.

[0007] In view of the above circumstances, at least some embodiments of the present invention aim to provide a solenoid actuator and a method for manufacturing the same that have excellent suction characteristics and can be manufactured at low cost. [Means for solving the problem]

[0008] [1] Solenoid actuators according to at least some embodiments of the present invention are Coil and, A first stator and a second stator are arranged axially separated by an air gap so as to form a magnetic path around the coil, A movable element configured to move axially toward the second stator from its original position radially inward of the first stator by the magnetic force generated by energizing the coil, Equipped with, The first stator is, York 1 and A first cylindrical member fixed to the inner circumference of the first yoke and forming an air gap, Includes.

[0009] [2] In some embodiments, in the configuration of [1] above, The first cylindrical member is A magnetic tube formed from a magnetic material, A non-magnetic layer formed on the inner surface of the magnetic cylinder, Includes, The first cylindrical member is configured to guide the movable element in the axial direction by bringing the movable element into sliding contact with a non-magnetic layer.

[0010] [3] In some embodiments, in the configuration of [1] or [2] above, The first yoke has a first through hole into which the first cylindrical member is press-fitted. The inner wall of the first through hole is The contact area with the outer surface of the first cylindrical member, In the axial direction, a non-contact region is located adjacent to the contact region on the opposite side of the second stator, and Includes, The diameter of the first through-hole is the same in the contact area and the non-contact area.

[0011] [4] In some embodiments, in any of the configurations described in [1] to [3] above, The second stator is, Second York and A second cylindrical member fixed to the inner circumference of the second yoke and forming an air gap, Includes.

[0012] [5] In some embodiments, in the configuration of [4] above, The second cylindrical member is provided so as to protrude from the second yoke toward the first stator.

[0013] [6] In some embodiments, in the configuration of [5] above, The second yoke decreases in thickness towards the air gap.

[0014] [7] The manufacturing method of a solenoid actuator according to at least some embodiments of the present invention includes a step of arranging at least a part of a first yoke and a second stator around a coil, a step of axially positioning a first cylindrical member with respect to a reference surface of at least a part of the second stator, a step of fixing the axially positioned first cylindrical member to the inner peripheral side of the first yoke so that a first stator formed by the first yoke and the first cylindrical member forms a magnetic path together with the second stator around the coil, a step of assembling a mover so as to be located at the original position radially inside the first stator, and comprises.

Advantages of the Invention

[0015] According to at least some embodiments of the present invention, when assembling the first cylindrical member to the first yoke, by axially positioning the first cylindrical member with respect to the second stator, it is possible to reduce related components that affect the air gap. As a result, it becomes possible to manage the air gap with high precision, and a solenoid actuator having excellent suction characteristics can be realized at a low cost.

Brief Description of the Drawings

[0016] [Figure 1] It is a cross-sectional view schematically showing the configuration of a solenoid actuator according to an embodiment. [Figure 2] It is an enlarged view of part A in FIG. 1. [Figure 3] It is a cross-sectional view schematically showing the configuration of a solenoid actuator according to another embodiment. [Figure 4A] It is a diagram showing an assembly procedure of a solenoid actuator according to an embodiment. [Figure 4B] It is a diagram showing an assembly procedure of a solenoid actuator according to an embodiment. [Figure 4C] It is a diagram showing an assembly procedure of a solenoid actuator according to an embodiment. [Figure 5A]This figure shows the assembly procedure for a solenoid actuator according to another embodiment. [Figure 5B] This figure shows the assembly procedure for a solenoid actuator according to another embodiment. [Figure 5C] This figure shows the assembly procedure for a solenoid actuator according to another embodiment. [Figure 5D] This figure shows the assembly procedure for a solenoid actuator according to another embodiment. [Figure 6] This figure shows a specific structural example of a solenoid actuator according to another embodiment. [Modes for carrying out the invention]

[0017] Hereinafter, several embodiments of the present invention will be described with reference to the attached drawings. However, the dimensions, materials, shapes, relative arrangements, etc., of the components described as embodiments or shown in the drawings are not intended to limit the scope of the present invention, but are merely illustrative examples.

[0018] Figure 1 is a schematic cross-sectional view showing the configuration of a solenoid actuator according to one embodiment. Figure 2 is an enlarged view of part A in Figure 1. Figure 3 is a schematic cross-sectional view showing the configuration of a solenoid actuator according to another embodiment. In Figures 1 and 3, the resin mold for the solenoid actuator is omitted from the illustration. Figures 1 to 3 show the state where coil 3 is de-energized and the movable element 50 is in its original position. The original position of the movable element 50 can be rephrased as the stroke start position where the stroke amount of the solenoid actuators 1A and 1B is zero. In addition, although Figures 1 and 3 show the magnetic path 4 only on one side of coil 3 (the left side in the figures), similar magnetic paths 4 are formed on both sides of the ring-shaped coil 3 (the right side in the figures). Hereinafter, solenoid actuators 1A and 1B may be collectively referred to as solenoid actuator 1.

[0019] In some embodiments, as shown in Figures 1 and 3, the solenoid actuator 1 (1A, 1B) includes a coil 3, stators 10, 20 for forming a magnetic path 4 around the coil 3, and a movable element 50 that is axially movable by the magnetic force generated by the coil 3.

[0020] Coil 3 is constructed by winding a wire made of a conductor such as copper or a copper alloy around the central axis O of the solenoid actuator 1. Coil 3 as a whole is roughly annular with respect to the central axis O. Terminals (not shown) are electrically connected to coil 3, and power is supplied to coil 3 through these terminals. When coil 3 is energized, a magnetic force is generated to attract the movable element 50. The coil 3 may be housed in a bobbin (not shown).

[0021] The stator (10,20) includes a first stator 10 and a second stator 20 located on either side of the coil 3 in the axial direction of the solenoid actuator 1. The stator (10,20) is made of a magnetic material, which may be iron, for example, and is arranged in an annular shape around a central axis O so as to surround the coil 3.

[0022] The first stator 10 and the second stator 20 are arranged so as to face each other in the axial direction, separated by an air gap 11, on the inner circumference side of the coil 3 and on the outer circumference side of the movable element 50, which will be described later. The air gap 11 is provided to restrict the magnetic flux flow from the first stator 10 directly to the second stator 20 without passing through the movable element 50, and to efficiently direct the magnetic flux into the magnetic path 4 that goes from the first stator 10 to the second stator 20 via the movable element 50.

[0023] In the examples shown in Figures 1 and 3, the first stator 10 and the second stator 20 come into contact at the contact portion 12 located on the outer circumference of the coil 3. In this case, the first stator 10 and the second stator 20 may be integrally molded by a resin mold (not shown) with the first stator 10 and the second stator 20 facing each other on the inner circumference side of the coil 3 via an air gap 11 and in contact with each other at the contact portion 12 on the outer circumference side of the coil 3. The position of the contact portion 12 between the first stator 10 and the second stator 20 is not particularly limited. The contact portion 12 may be located at the center of the coil 3 in the axial direction, as in the examples in Figures 1 and 3, or it may be located at a position different from the center of the coil 3.

[0024] In other embodiments, the solenoid actuator 1 does not have a contact point between the first stator 10 and the second stator 20. For example, if the solenoid actuator 1 includes one or more stators other than the first stator 10 and the second stator 20, the one or more other stators may be located between the first stator 10 and the second stator 20 and together with the first stator 10 and the second stator 20 to form a magnetic path 4. In this way, the presence of other stators between the first stator 10 and the second stator 20 may result in a configuration where the first stator 10 and the second stator 20 do not come into direct contact with each other. Furthermore, gaps may exist between the multiple stators, including the first stator 10 and the second stator 20.

[0025] In some embodiments, as shown in Figures 1 to 3, the first stator 10 includes a first yoke 14 and a first cylindrical member 30 fixed to the inner circumference of the first yoke 14.

[0026] In some embodiments, as shown in Figures 1 to 3, the first cylindrical member 30 faces the second stator 20 in the axial direction, separated by an air gap 11 between the first stator 10 and the second stator 20. Specifically, the tip 31 of the first cylindrical member 30 is not in contact with the tip 21 of the second stator 20, but is separated from the second stator 20 by the air gap 11. Here, the air gap 11 refers to the smallest gap between the first stator 10, which includes the first yoke 14 and the first cylindrical member 30, and the second stator 20 on the inner circumference side of the coil 3.

[0027] The first cylindrical member 30 may be positioned such that its tip 31 is located within a radial position range that overlaps with the tip 21 of the second stator 20. Furthermore, the first cylindrical member 30 may be positioned such that its tip 31 protrudes from the first yoke 14 toward the second stator 20.

[0028] Thus, when the first stator 10 includes the first yoke 14 and the first cylindrical member 30, it becomes easier to control the air gap 11 with high precision. In other words, when assembling the first cylindrical member 30 to the first yoke 14, the axial positioning of the first cylindrical member 30 with respect to the second stator 20 can be performed, thereby reducing the number of related parts that affect the air gap 11. This makes it possible to control the air gap 11 with high precision, and a solenoid actuator 1 with excellent suction characteristics can be realized at a low cost. For example, consider the case where, when assembling the first cylindrical member 30 to the first yoke 14, the axial position of the tip 31 of the first cylindrical member 30 is adjusted with reference to the axial end face 22 of the second stator 20 opposite to the first stator 10 (the reference surface 22 of the second stator 20). In this case, since only the dimensions of the second stator 20 (the axial dimension of the second stator 20 from the reference surface 22 to the tip 21) substantially affect the air gap 11, a highly accurate air gap 11 can be easily formed. Specific examples of the axial positioning of the first cylindrical member 30 relative to the first yoke 14 will be described in detail later with reference to Figures 4A to 4B and 5A to 5B.

[0029] The first yoke 14 of the first stator 10 is made of a magnetic material, which may be iron, for example, and is arranged together with the second stator 20 to surround the coil 3 (cover the annular coil 3). The first yoke 14 may contact the second stator 20 at a contact portion 12 on the outer circumference side of the coil 3. The first yoke 14 has a first through-hole 15 for receiving the first cylindrical member 30. The first through-hole 15 may be a circular hole concentric with the central axis O of the solenoid actuator 1.

[0030] As shown in Figure 2, the inner wall of the first through-hole 15 of the first yoke 14 includes a contact area 15a that contacts the outer circumferential surface of the first cylindrical member 30 and a non-contact area 15b that does not contact the outer circumferential surface of the first cylindrical member 30. The non-contact area 15b is adjacent to the contact area 15a in the axial direction. The non-contact area 15b is located on the opposite side of the contact area 15a from the second stator 20 in the axial direction.

[0031] In some embodiments, the inner diameter of the first through-hole 15 is the same in the contact region 15a and the non-contact region 15b. That is, the inner wall of the first through-hole 15 does not have a step that restricts the axial position of the first cylindrical member 30 relative to the first yoke 14. Therefore, the axial positioning of the first cylindrical member 30 relative to the second stator 20 is not hindered by a step in the inner wall of the first through-hole 15. Therefore, when assembling the first cylindrical member 30 to the first yoke 14, it becomes possible to appropriately adjust the axial position of the tip 31 of the first cylindrical member 30, making it easier to control the air gap 11 with high precision.

[0032] In the exemplary embodiment shown in Figure 2, the inner wall of the first through-hole 15 is composed only of a contact area 15a and a non-contact area 15b, and the inner diameter of the first through-hole 15 is constant regardless of the axial position. In other embodiments, the inner wall of the first through-hole 15 includes, in addition to the contact area 15a and the non-contact area 15b, other areas with different inner diameters from the contact area 15a and the non-contact area 15b.

[0033] The first cylindrical member 30 is provided within the first through hole 15 and fixed to the inner circumference of the first yoke 14. The means for fixing the first cylindrical member 30 to the first yoke 14 are not particularly limited. For example, the first cylindrical member 30 may be press-fitted into the first through hole 15, or the first cylindrical member 30 may be welded to the inner wall of the first through hole 15. Alternatively, the entire circumference or part of the overlapping portion between the first cylindrical member 30 and the inner wall of the first through hole 15 may be crimped by spot riveting.

[0034] In some embodiments, as shown in Figure 2, the first cylindrical member 30 includes a magnetic cylinder 32 having an outer peripheral surface that contacts the inner wall of the first through hole 15 of the first yoke 14, and a non-magnetic layer 34 formed on the inner peripheral surface of the magnetic cylinder 32.

[0035] The magnetic cylinder 32 is made of a magnetic material, which may be iron, for example, and faces the second stator 20 across the air gap 11. That is, of the magnetic material portions of the first stator 10, including the first yoke 14 and the first cylindrical member 30, the magnetic cylinder 32 is positioned closest to the tip 21 of the second stator 20. The radial position range of the magnetic cylinder 32 may overlap with the radial position range of the tip 21 of the second stator 20, which forms an air gap 11 with the magnetic cylinder 32.

[0036] The non-magnetic layer 34 of the first cylindrical member 30 is provided on the inner circumferential surface of the magnetic cylinder 32 so as to face the outer circumferential surface of the movable element 50. As a result, the first cylindrical member 30 can guide the movable element 50 in the axial direction by bringing the movable element 50 into sliding contact with the non-magnetic layer 34. The non-magnetic layer 34 may be made of a low-friction material such as copper or PTFE (polytetrafluoroethylene). The non-magnetic layer 34 may be formed on the inner surface of the first cylindrical member 30 by a construction method such as sintering or impregnation. In an exemplary embodiment, the non-magnetic layer 34 is formed by impregnating a porous layer of copper alloy formed by sintering with a resin material containing PTFE.

[0037] In this way, by providing a non-magnetic layer 34 on the inner circumferential surface of the magnetic cylinder 32 and having the first cylindrical member 30 for forming the air gap 11 also serve as a guide for the movable element 50, it is possible to achieve high precision of the air gap 11 while suppressing an increase in the number of parts.

[0038] Generally, the guide (bearing) that constrains the radial position of the movable element and guides it axially is located in a different place from the radial magnetic gap between the yoke and the movable element. In this case, if the axis of the yoke is eccentric with respect to the guide that restricts the radial position of the movable element, the magnetic gap between the movable element and the yoke on the outer circumference of the movable element will also be affected by the eccentricity. For this reason, it is necessary to ensure a relatively wide magnetic gap between the movable element and the yoke on the outer circumference of the movable element, taking into account the effect of axial misalignment of the yoke on the guide (bearing). In this regard, as shown in the exemplary embodiment in Figure 2, if the first cylindrical member 30, which has a guide function for guiding the movable element 50 in the axial direction, is fixed to the inner circumference side of the first yoke 14, the effect of axial misalignment of the first yoke 14 on the guide (first cylindrical member 30) can be substantially eliminated. For this reason, the radial gap tr that needs to be secured between the first cylindrical member 30 and the movable element 50 only needs to be large enough to allow the assembly of the movable element 50. As a result, by reducing the magnetic gap t_gap, the magnetic flux from the first yoke 14 toward the movable element 50 can be increased. In the example shown in Figure 2, the magnetic gap t_gap relating to the magnetic flux flow from the first stator 10 to the movable element 50 is the sum of the radial gap tr and the thickness t_guide of the non-magnetic layer 34.

[0039] In some embodiments, the second stator 20 includes a second yoke 24 and a second cylindrical member 40 fixed to the inner circumference of the second yoke 24, as shown in Figure 3.

[0040] The second yoke 24 is formed of a magnetic material, which may be iron, for example, and is arranged together with the first stator 10 to surround the coil 3. The second yoke 24 may contact the first stator 10 at the contact portion 12 on the outer circumference side of the coil 3. The second yoke 24 has a second through-hole 25 for receiving the second cylindrical member 40. The second through-hole 25 may be a circular hole concentric with the central axis O of the solenoid actuator 1.

[0041] In the exemplary embodiment shown in Figure 3, the second cylindrical member 40 has a tip 21 of the second stator 20 that forms an air gap 11 between it and the first stator 10.

[0042] In this way, by providing the second cylindrical member 40, which is directly related to the air gap 11, separately from the second yoke 24, the air gap 11 can be controlled with greater precision compared to when the entire second stator 20 is constructed as a single unit. For example, consider the case where, when assembling the first cylindrical member 30 to the first yoke 14, the position of the tip 31 of the first cylindrical member 30 is adjusted with reference to the reference surface 22 of the second stator 20 (i.e., the axial end face 22 of the second yoke 24 opposite to the first stator 10). In this case, after adjusting the axial position of the tip 31 of the first cylindrical member 30 with respect to the axial end face 22 of the second yoke 24, the second cylindrical member 40 may be axially aligned with respect to the axial end face 22 of the second yoke 24 when assembling the second cylindrical member 40 to the second yoke 24. As a result, the only dimension of the second cylindrical member 40 of the second stator 20 (the axial dimension of the second cylindrical member 40 from the reference surface 22 of the second yoke 24 to the air gap 11) substantially affects the air gap 11, and a highly accurate air gap 11 can be easily formed. The axial positioning of the second cylindrical member 40 relative to the second yoke 24 will be described in detail later with reference to Figure 5C.

[0043] In some embodiments, as shown in Figure 3, the second cylindrical member 40 is provided so as to protrude from the second yoke 24 toward the first stator 10. In other words, the tip 21 of the second stator 20 formed by the second cylindrical member 40 is located on the first stator 10 side, beyond the tip of the second yoke 24, in the axial direction.

[0044] Some solenoid actuators, such as linear solenoids, are desirable to have a linear characteristic in which the attractive force changes with respect to current. To achieve this linear characteristic, it is advantageous to make the tip of the second stator, which is located downstream in the direction of movement of the movable element from its original position when the coil is energized, tapered toward the air gap. In this regard, as described above, by making the second cylindrical member 40 that forms the air gap 11 protrude axially from the second yoke 24, the overall shape of the second stator 20 formed by the second yoke 24 and the second cylindrical member 40 can be made closer to the tapered shape described above.

[0045] In the exemplary embodiment shown in Figure 3, the second yoke 24 has a thickness t that decreases toward the air gap 11. That is, the second yoke 24 has a tip section 26 in the tip region facing the air gap 11, in which the thickness t decreases toward the air gap 11. Here, the thickness t of the second yoke 24 is the radial dimension of the second yoke 24.

[0046] Thus, the second yoke 24 has a thickness distribution that decreases as it approaches the air gap 11. Combined with the configuration in which the second cylindrical member 40 protrudes from the second yoke 24 toward the first stator 10, the overall shape of the second stator 20 can be made even closer to the aforementioned tapered shape.

[0047] When the coil 3 is energized, magnetic flux flows through the magnetic path 4 formed around the coil 3 by the first stator 10 and the second stator 20 of the above configuration. The magnetic path 4 includes not only the first stator 10 (first yoke 14 and first cylindrical member 30) and the second stator 20, but also the movable element 50. As a result, the movable element 50 is attracted by the magnetic flux flowing through the magnetic path 4 and moves axially from its original position radially inward of the first stator 10 towards the second stator 20.

[0048] The second stator 20 has a cavity 28 formed radially inward to receive the movable element 50 which approaches in the axial direction when the coil 3 is energized. In the embodiment shown in Figure 1, the cavity 28 is defined by a second stator 20 which is a single integrated unit. In the embodiment shown in Figure 3, the cavity 28 is defined by a second cylindrical member 40 of the second stator 20.

[0049] In some embodiments, the movable element 50 is a plunger 52 provided at the end of the shaft 54, which is the output shaft of the solenoid actuator 1, as shown in Figures 1 and 3. The plunger 52 has a through hole into which the shaft 54 ​​is press-fitted. The shaft 54 ​​is press-fitted into the through hole of the plunger 52 such that the axis of the shaft 54 ​​aligns with the axis of the plunger 52.

[0050] The plunger 52, which serves as the movable element 50, is made of a magnetic material, which may be iron, for example, and is attached to the outer circumference of the shaft 54. The diameter of the plunger 52 is larger than the diameter of the shaft 54, and smaller than the inner diameter of the first cylindrical member 30 of the first stator 10. Also, the diameter of the plunger 52 is smaller than the diameter of the cavity 28 formed by the second stator 20.

[0051] When coil 3 is de-energized, shaft 54 ​​is biased in the opposite direction to arrow B by a spring (not shown), and plunger 52, acting as the movable element 50, is positioned radially inward of the first stator 10 (first cylindrical member 30). At this time, plunger 52 only needs to be substantially positioned radially inward of the first cylindrical member 30, and the end of plunger 52 may protrude from the first stator 10 (first cylindrical member 30) toward the second stator 20. In contrast, when the coil 3 is energized, the plunger 52, acting as the movable element 50, enters the cavity 28 formed radially inward of the second stator 20. At this time, it is sufficient that at least a portion of the plunger 52 is located within the cavity 28, and the remaining portion of the plunger 52 may protrude from the cavity 28 toward the first stator 10.

[0052] The shaft 54 ​​to which the plunger 52 in the above configuration is fixed extends through the second stator 20 to the outside of the solenoid actuator 1. The shaft 54 ​​moves in the direction of arrow B when the solenoid actuator 1 is operated, transmitting the driving force of the solenoid actuator 1 to an external device (not shown). The external device driven by the solenoid actuator 1 is not particularly limited, but could be, for example, a spool that hydraulically controls the valve timing of the intake and exhaust valves of a vehicle's engine.

[0053] The shaft 54 ​​may be slidably supported toward the second stator 20 by a bearing. In the embodiment shown in Figure 1, the solenoid actuator 1 has a bearing 53A that slidably supports the shaft 54 ​​on the second stator 20. The bearing 53A may be attached to the second stator 20 via a bearing holder 56. In the embodiment shown in Figure 3, the radially inner portion of the second cylindrical member 40, which constitutes a part of the second stator 20, functions as a bearing portion 53B, and the shaft 54 ​​is slidably supported by the bearing portion 53B of the second cylindrical member 40.

[0054] Next, referring to Figures 4A to 5D, the manufacturing method of the solenoid actuator 1 (1A, 1B) will be described.

[0055] Figures 4A to 4C show the assembly procedure of a solenoid actuator 1A according to one embodiment. When assembling the solenoid actuator 1A, the first yoke 14 and the second stator 20 are positioned around the coil 3. Then, as shown in Figures 4A to 4B, the first cylindrical member 30 is positioned axially with respect to the reference plane 22 of the second stator 20.

[0056] When positioning the first cylindrical member 30, a jig 110 may be used to ensure that the tip 31 of the first cylindrical member 30 is in a desired axial position relative to the reference surface 22. In the embodiment shown in Figure 4A, prior to inserting the first cylindrical member 30 into the first through hole 15 of the first yoke 14, a substantially cylindrical jig 110 is placed on the inner circumference side of the second stator 20. At this time, the reference surface 22 of the second stator 20 and the lower end surface 112 of the jig 110 are in contact with the upper surface (flat surface 100) of the base. In this case, the upper end surface 114 of the jig 110 is located higher than the reference surface 22 of the second stator 20 by the dimension of the jig 110. Next, as shown in Figure 4A, the first cylindrical member 30 is inserted into the first through-hole 15 of the first yoke 14 from the opposite side of the second stator 20. When the tip 31 of the first cylindrical member 30 contacts the upper end surface 114 of the jig 110, the insertion of the first cylindrical member 30 is stopped, as shown in Figure 4B. In this way, the first cylindrical member 30 is positioned axially with respect to the reference plane 22 of the second stator 20.

[0057] The positioned first cylindrical member 30 is fixed to the inner circumference of the first yoke 14 so as to be immovable relative to the first yoke 14. As a result, the first stator 10 and the second stator 20, including the first yoke 14 and the first cylindrical member 30, form a magnetic path 4 (see Figure 1) around the coil 3. The first cylindrical member 30 can be fixed to the first yoke 14 by press-fitting or welding. When the first cylindrical member 30 is press-fitted into the first through-hole 15 of the first yoke 14, the positioning of the first cylindrical member 30 and the fixing of the first cylindrical member 30 to the first yoke 14 are performed simultaneously. In contrast, when the first cylindrical member 30 is fixed to the first yoke 14 by welding, the fixing of the first cylindrical member 30 to the first yoke 14 is performed after the positioning of the first cylindrical member 30.

[0058] After the positioning and fixing of the first cylindrical member 30 is complete, the jig 110 can be removed by any method. For example, if the jig 110 has a structure that can be disassembled, the jig 110 may be disassembled into multiple parts and then each part may be removed from the opening of the second stator 20. Alternatively, if the jig 110 has a structure that can be deformed, the jig 110 may be deformed so that its dimensions are reduced and then removed from the opening of the second stator 20.

[0059] Next, as shown in Figure 4C, the plunger 52, which serves as the movable element 50, is assembled to the first stator 10 and the second stator 20. The axial position of the movable element 50 (plunger 52) at this stage is not particularly limited. The movable element 50 (plunger 52) may be mounted to the original position radially inward of the first stator 10 (first cylindrical member 30) by assembling a spring (not shown). Furthermore, in the example shown in Figure 4C, the shaft 54 ​​is slidably supported by the bearing 53A by assembling the bearing 53A to the second stator 20 via the bearing holder 56.

[0060] Subsequently, the first stator 10 and the second stator 20 are integrally molded using a resin mold (not shown) to obtain the solenoid actuator 1A.

[0061] Figures 5A to 5D show the assembly procedure for a solenoid actuator 1B according to another embodiment.

[0062] In another embodiment, the first yoke 14 and the second yoke 24, which is part of the second stator 20, are initially arranged around the coil 3 (see Figure 5A). Then, the first cylindrical member 30 is positioned axially with respect to the reference plane 22 of the second yoke 24.

[0063] When positioning the first cylindrical member 30, a jig 120 may be used to ensure that the tip 31 of the first cylindrical member 30 is in a desired axial position relative to the reference plane 22. In the embodiment shown in Figure 5A, a positioning jig 120 for the first cylindrical member 30 is set up in advance prior to inserting the first cylindrical member 30 into the first through hole 15 of the first yoke 14. The jig 120 has a flat surface 100 and a substantially cylindrical protrusion 122. The protrusion 122 is located on the inner circumference side of the flat surface 100 and is provided projecting upward from the flat surface 100. The jig 120 is installed such that the flat surface 100 of the jig 120 is in contact with the reference surface 22 of the second yoke 24, and the protrusion 122 of the jig 120 is located on the inner circumference side of the second yoke 24. At this time, the upper end surface 124 of the protrusion 122 of the jig 120 is located higher than the reference surface 22 of the second yoke 24 by the amount of protrusion of the protrusion 122 from the flat surface 100. Next, as shown in Figure 5A, the first cylindrical member 30 is inserted into the first through hole 15 of the first yoke 14 from the opposite side of the second yoke 24. When the tip 31 of the first cylindrical member 30 contacts the upper end surface 124 of the protrusion 122 of the jig 120, the insertion of the first cylindrical member 30 is stopped, as shown in Figure 5B. In this way, the first cylindrical member 30 is positioned axially with respect to the reference plane 22 of the second yoke 24, which constitutes a part of the second stator 20.

[0064] Subsequently, the positioned first cylindrical member 30 is fixed to the inner circumference of the first yoke 14 so as to be immovable relative to the first yoke 14. The first cylindrical member 30 can be fixed to the first yoke 14 by press-fitting or welding. When the first cylindrical member 30 is press-fitted into the first through-hole 15 of the first yoke 14, the positioning of the first cylindrical member 30 and the fixing of the first cylindrical member 30 to the first yoke 14 are performed simultaneously.

[0065] Next, as shown in Figure 5C, the second cylindrical member 40, which constitutes a part of the second stator 20, is inserted into the second through-hole 25 of the second yoke 24, thereby positioning and fixing the second cylindrical member 40 with respect to the second yoke 24. In this case, when positioning the second cylindrical member 40, a jig 130 may be used to achieve a state in which the tip of the second cylindrical member 40 (i.e., the tip 21 of the second stator 20) is at a desired axial position relative to the reference plane 22 of the second yoke 24. The jig 130 has a flat surface 132 and a recess 134 surrounded by the flat surface 132. The depth of the recess 134 is set to a dimension that can accommodate the bearing portion 53B of the second cylindrical member 40. The jig 130 is positioned so that the flat surface 132 of the jig 130 is in contact with the reference surface 22 of the second yoke 24 and the shoulder portion 42 of the second cylindrical member 40. By bringing the reference surface 22 of the second yoke 24 and the shoulder portion 42 of the second cylindrical member 40 into contact with the flat surface 132 of the jig 130 in this manner, the tip of the second cylindrical member 40 (i.e., the tip 21 of the second stator 20) is positioned axially relative to the second yoke 24.

[0066] The second cylindrical member 40, thus positioned, is fixed to the inner circumference of the second yoke 24 so as to be immovable relative to the second yoke 24. As a result, the first stator 10 (first yoke 14 and first cylindrical member 30) and the second stator 20 (second yoke 24 and second cylindrical member 40) form a magnetic path 4 (see Figure 3) around the coil 3. The second cylindrical member 40 can be fixed to the second yoke 24 by press-fitting or welding. When the first cylindrical member 30 is press-fitted into the first through-hole 15 of the first yoke 14, the positioning of the first cylindrical member 30 and the fixing of the first cylindrical member 30 to the first yoke 14 are performed simultaneously.

[0067] Subsequently, as shown in Figure 5D, the plunger 52, which serves as the movable element 50, is assembled to the first stator 10 and the second stator 20. The axial position of the movable element 50 (plunger 52) at this stage is not particularly limited. The movable element 50 (plunger 52) may be mounted to the original position radially inward of the first stator 10 (first cylindrical member 30) by assembling a spring (not shown). Furthermore, in the example shown in Figure 5D, the shaft 54 ​​is slidably supported by the second cylindrical member 40 of the second stator 20.

[0068] Finally, the first stator 10 and the second stator 20 can be integrally molded using a resin mold (not shown) to obtain the solenoid actuator 1B.

[0069] As described above with reference to Figures 4A to 5D, when assembling the first cylindrical member 30 to the first yoke 14, the axial positioning of the first cylindrical member 30 with respect to the reference plane 22 of the second stator 20 reduces the number of related parts that affect the air gap 11. This makes it possible to control the air gap 11 with high precision, and a solenoid actuator 1 (1A, 1B) with excellent suction characteristics can be realized at low cost.

[0070] Next, a specific structural example of the solenoid actuator 1B shown in Figure 3 will be explained with reference to Figure 6. Note that in the following explanation, we will omit the description of the components that are common to the solenoid actuator 1B shown in Figure 3.

[0071] Figure 6 is a cross-sectional view showing a solenoid actuator according to one embodiment. As shown in the figure, the solenoid actuator 1 includes a coil 3, a first stator 10 and a second stator 20, and a movable element 50 (plunger 52). Coil 3 is formed by winding a wire made of a conductor such as copper or a copper alloy around a bobbin 60. The bobbin 60 is substantially surrounded by a first stator 10 and a second stator 20. However, the first stator 10 (first yoke 14) has a notch in a certain circumferential area, and the terminal holding portion 62 of the bobbin 60 is exposed at the notch of the first yoke 14. The base end of a terminal 64 is embedded in the terminal holding portion 62 of the bobbin 60. The terminal 64 is electrically connected to the wire making up coil 3 inside the bobbin 60. Furthermore, in the solenoid actuator 1B, the coil 3 and bobbin 60, and the first stator 10 and second stator 20 are integrally molded in a resin mold 70 and embedded in the resin mold 70. The terminal 64 penetrates the resin mold 70 from the terminal holding portion 62 of the bobbin 60 and protrudes into a recess 72 provided in the resin mold 70, and is electrically connectable to an external terminal that fits into the recess 72. The resin mold 70 may also have a protrusion (not shown) that contacts the rear end surface of the movable element 50 (plunger 52) in its original position.

[0072] In this specification, expressions describing relative or absolute arrangements such as "in a certain direction," "along a certain direction," "parallel," "orthogonal," "center," "concentric," or "coaxial" shall not only describe such arrangements strictly, but also describe states of relative displacement with tolerances or angles or distances that allow for the same function to be achieved. For example, expressions such as "identical," "equal," and "homogeneous" that describe things being in an equal state not only describe a state of being strictly equal, but also describe a state in which there is a tolerance or a difference that is sufficient to achieve the same function. Furthermore, in this specification, expressions describing shapes such as quadrilaterals and cylindrical shapes shall not only represent geometrically precise quadrilaterals and cylindrical shapes, but also shapes that include uneven surfaces, chamfered surfaces, etc., to the extent that the same effect can be achieved. Furthermore, in this specification, the expressions “equipment,” “includes,” or “possess” of a component are not exclusive expressions that exclude the existence of other components. [Explanation of Symbols]

[0073] 1,1A,1B Solenoid Actuator 3 coils 10 1st stator 11 Air gap 14. First York 15. First through hole 15a Contact area 15b Non-contact area 20 Second stator 22 Reference plane 24 Second York 30 First cylindrical member 32 Magnetic tube 34 Non-magnetic layer 40 Second cylindrical member 50 mover

Claims

1. Coil and, A first stator and a second stator are arranged axially separated by an air gap so as to form a magnetic path around the coil, A movable element configured to move in the axial direction toward the second stator from its original position radially inward of the first stator by the magnetic force generated by energizing the coil, Equipped with, The first stator is, York 1 and A first cylindrical member fixed to the inner circumference of the first yoke and forming the air gap, Includes, The second stator is, Second York and, A second cylindrical member fixed to the inner circumference of the second yoke and forming the air gap, including Solenoid actuator.

2. The first cylindrical member is A magnetic tube formed from a magnetic material, A non-magnetic layer formed on the inner circumferential surface of the magnetic cylinder, Includes, The first cylindrical member is configured to guide the movable element in the axial direction by causing the movable element to slide against the non-magnetic layer. The solenoid actuator according to claim 1.

3. The first yoke has a first through hole into which the first cylindrical member is press-fitted, The inner wall of the first through hole is The contact area with the outer circumferential surface of the first cylindrical member, In the axial direction, a non-contact region located adjacent to the contact region on the opposite side from the second stator, with the contact region in between, Includes, The diameter of the first through-hole is the same in the contact region and the non-contact region. The solenoid actuator according to claim 1 or 2.

4. The second cylindrical member is provided so as to protrude from the second yoke toward the first stator. The solenoid actuator according to claim 1 or 2.

5. The second yoke decreases in thickness toward the air gap. The solenoid actuator according to claim 4.

6. The steps include arranging the first yoke and the second yoke of the second stator around the coil, The steps include positioning the first cylindrical member axially with respect to the reference plane of the second yoke, The first cylindrical member, positioned in the axial direction, is fixed to the inner circumference of the first yoke such that the first stator formed by the first yoke and the first cylindrical member together with the second stator forms a magnetic path around the coil; The steps include: positioning a second cylindrical member in the axial direction relative to the second yoke, which forms an air gap between itself and the first cylindrical member; and fixing the positioned second cylindrical member to the inner circumference of the second yoke to form the second stator; The steps include assembling the movable element to the first stator and the second stator, Equipped with A method for manufacturing a solenoid actuator.

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