electromagnet

Abstract

To provide an electromagnet having a configuration capable of suppressing rattling of a coil bobbin without increasing the number of components.SOLUTION: Since a locking portion 52 provided in a case 50 restricts the movement of a coil bobbin 25, it is possible to suppress rattling of a coil bobbin 25 without providing another component such as a spacer. Further, in a solenoid 49, the area of the bottom surface 53 of the locking portion 52 is made smaller than the area of the cross section perpendicular to the central axis of an intermediate region 57, such that rattling of the coil bobbin 25 can be suppressed without reducing the attractive force (thrust force).SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to an electromagnet, and more particularly to an electromagnet having a configuration that suppresses rattle of a coil bobbin. [Background technology]

[0002] Electromagnets such as linear solenoids and rotary solenoids are provided with an excitation coil to generate a magnetic flux flow in the magnetic material that constitutes the magnetic circuit. In most cases, this coil is formed by winding a coil wire around a coil bobbin. FIG. 14 is a cross-sectional view of an electromagnet according to the prior art. In FIG. 14, reference numeral 100 denotes a solenoid, 101 denotes a frame, 102a and 102b denote legs, 102c denotes a bottom, 102d denotes a protrusion, 103 denotes a coil bobbin, 103a denotes a flange, 104 denotes a subframe, 104a denotes a through hole, 105 denotes an excitation coil, 106 denotes a cylindrical body, 106a denotes a flange, 107 denotes a seal, 108 denotes a movable core, and 109 denotes an air damper chamber.

[0003] FIG. 14 shows an electromagnet disclosed in Japanese Patent Application Laid-Open Publication No. 2011-071241. The solenoid 100 is an open-frame solenoid and includes a frame 101, which serves as both a yoke and an outer shell, and a subframe 104. The frame 101 includes a pair of legs 102a and 102b and a bottom 102c. A protrusion 102d is formed in the center of the bottom 102c by half-punching. Furthermore, one open end of a cylindrical body 106 is pressed against the bottom 102c via a sealing material 107 so that the protrusion 102d can be inserted, thereby making the one open end of the cylindrical body 106 airtight. Furthermore, a movable iron core 108 is inserted from the other open end of the cylindrical body 106, and the space formed by one end of the movable iron core 108, the inner surface of the cylindrical body 106, and the inner surface of the protrusion 102d serves as an air damper chamber 109. When the exciting coil 105 wound around the coil bobbin 103 is energized, the movable iron core 108 slides inside the cylindrical body 106 toward the bottom 102c. At this time, the air in the air damper chamber 109 is compressed, passes through the small gap between the inner surface of the cylindrical body 106 and the movable iron core 108, and gradually leaks out through the through hole 104a in the subframe 104.

[0004] Incidentally, as in the solenoid 100, for structural reasons such as providing an air damper or providing a device such as a sensor near the coil bobbin, it is sometimes necessary to provide a gap between the yoke, which forms the outer shell, and the coil bobbin. A gap between the yoke and the coil bobbin can cause the coil bobbin to rattle, so some means must be used to hold the coil bobbin in a predetermined position. In the solenoid 100 of JP 2011-071241 A, the flange 106a on the air damper chamber 109 side of the cylindrical body 106 and the seal member 107 are brought into contact with the flange 103a on the air damper chamber 109 side of the coil bobbin 103 to hold the coil bobbin 103.

[0005] If the gap is relatively narrow, it can be addressed by a means such as the solenoid 100 disclosed in JP 2011-071241 A. If the gap becomes wider than this, other means, such as providing a spacer made of a non-magnetic material, become necessary. However, providing a spacer increases the number of parts and does not contribute to improving the performance of the electromagnet, so it is not a desirable solution. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Laid-Open No. 2011-071241 Summary of the Invention [Problem to be solved by the invention]

[0007] In order to solve the above-mentioned problems, an object of the present invention is to provide an electromagnet having a configuration that can suppress rattle of the coil bobbin without increasing the number of parts. [Means for solving the problem]

[0008] The invention described in claim 1 is a winding drum formed in a substantially cylindrical shape, On one side of the central axis A first flange portion provided at the first end portion and a second flange portion provided at the first end portion of the winding drum On the other side of the central axis An electromagnet having a coil bobbin having a second flange portion provided at a second end, a coil formed by winding a coil wire around the winding drum portion of the coil bobbin, and a case made of a magnetic material, formed into a substantially cylindrical shape, and having the coil bobbin and the coil disposed therein, wherein the case The aforementioned the first end, or The aforementioned The first end portion is formed so as to protrude toward the inner peripheral surface of the first end portion. The aforementioneda locking portion having a flat surface facing the second end portion, the flat surface abutting against the first flange portion of the coil bobbin to restrict movement of the coil bobbin inside the case; The coil bobbin further includes an end cap made of a magnetic material and provided to abut against a first end surface of the case from one side of the central axis, the case abuts against the end cap only at the first end surface, and the area of ​​the first end surface is smaller than the cross-sectional area of ​​a middle region closer to the middle portion, which is on the other side of the central axis than the locking portion, in a direction perpendicular to the central axis. It is an electromagnet characterized by the following.

[0009] The invention described in claim 2 is an electromagnet comprising: a winding drum formed in a substantially cylindrical shape; a coil bobbin having a first flange provided at a first end on one side of a central axis of the winding drum; and a second flange provided at a second end on the other side of the central axis of the winding drum; a coil formed by winding a coil wire around the winding drum of the coil bobbin; and a case made of a magnetic material, formed in a substantially cylindrical shape, and having the coil bobbin and the coil disposed therein; wherein the case is formed to protrude toward an inner peripheral surface of the first end or a portion near the first end, and the second flange is provided at a a locking portion that has a flat surface facing the end side and that abuts against the first flange portion of the coil bobbin to restrict movement of the coil bobbin inside the case, and further has a member made of a magnetic material that generates a magnetic flux path together with the case when current is passed through the coil, and the area of ​​the surface of the case that contacts the member made of magnetic material on one side of the central axis with respect to the coil bobbin is smaller than the cross-sectional area in a direction perpendicular to the central axis of an intermediate region closer to the intermediate portion that is on the other side of the central axis than the locking portion It is an electromagnet characterized by the following.

[0010] The invention described in claim 3 is 2 In the invention described in The member made of magnetic material has a guide member and a movable magnetic pole guided in the direction of the central axis by the guide member, the guide member and the movable magnetic pole contact a bottom surface of the case from one side of the central axis with respect to the coil bobbin, the case contacts the member made of magnetic material only at the bottom surface, and the area of ​​the bottom surface is smaller than the cross-sectional area in a direction perpendicular to the central axis of an intermediate region closer to the intermediate portion which is on the other side of the central axis than the locking portion. It is an electromagnet characterized by the following. The invention described in claim 4 provides an electromagnet including a winding drum formed in a substantially cylindrical shape, a coil bobbin including a first flange portion provided at a first end portion on one side of the central axis of the winding drum, and a second flange portion provided at a second end portion on the other side of the central axis of the winding drum, a coil formed by winding a coil wire around the winding drum of the coil bobbin, and a case made of a magnetic material, formed in a substantially cylindrical shape, and having the coil bobbin and the coil disposed therein, wherein the case is formed to protrude toward the inner peripheral surface of the first end or a portion near the first end, and has a flat surface facing the second end. the electromagnet further comprises an end cap made of a magnetic material and provided to abut against a first end face of the case from one side of the central axis relative to the coil bobbin, and the flat surface of the end cap has a locking portion that abuts against the first flange portion of the coil bobbin to restrict movement of the coil bobbin inside the case, the case forms a gap with the end cap inside the first end face, and the area of ​​the first end face is smaller than the cross-sectional area in a direction perpendicular to the central axis of an intermediate region closer to the intermediate portion, which is on the other side of the central axis than the locking portion. . The invention described in claim 5 is an electromagnet characterized in that, in the invention described in claim 4, it further has a structural member arranged inside the case, and the case forms the gap between the end cap and the structural member inside the first end face. The invention described in claim 6 is an electromagnet including a winding drum formed in a substantially cylindrical shape, a coil bobbin having a first flange portion provided at a first end portion on one side of the central axis of the winding drum, and a second flange portion provided at a second end portion on the other side of the central axis of the winding drum, a coil formed by winding a coil wire around the winding drum of the coil bobbin, and a case made of a magnetic material, formed in a substantially cylindrical shape, and having the coil bobbin and the coil disposed therein, wherein the case is formed so as to protrude toward the inner peripheral surface of the first end or a portion near the first end, and has a flat surface facing the second end, and the flat surface is formed so as to protrude toward the inner peripheral surface of the coil bobbin. the electromagnet further comprises an end cap made of a magnetic material and provided to abut against a first end face of the case from one side of the central axis relative to the coil bobbin, the locking portion forming an inclined surface that is continuous with the first end face and cuts out an inner or outer peripheral surface of the case obliquely with respect to the central axis, the area of ​​the first end face being smaller than the cross-sectional area of ​​an intermediate region closer to the intermediate portion, which is on the other side of the central axis than the locking portion, in a direction perpendicular to the central axis. The invention described in claim 7 is an electromagnet characterized in that, in the invention described in any one of claims 1 to 6, it further has a fixed magnetic pole inserted into the coil bobbin, the case is formed so as to protrude toward the inner surface of the second end or the portion near the second end, and has a second flat surface facing the first end, and the second flat surface abuts against the second flange portion of the coil bobbin to restrict movement of the coil bobbin inside the case, and the second locking portion and the locking portion are formed integrally with the case. The invention described in claim 8 provides an electromagnet including a winding drum formed in a substantially cylindrical shape, a coil bobbin having a first flange provided at a first end of the winding drum and a second flange provided at a second end of the winding drum, a coil formed by winding a coil wire around the winding drum of the coil bobbin, a case made of a magnetic material and formed in a substantially cylindrical shape, in which the coil bobbin and the coil are disposed, and a fixed magnetic pole inserted into the coil bobbin, wherein the case is formed to protrude toward the inner peripheral surface of the first end or a portion near the first end, and has a flat surface facing the second end. a locking portion having a flat surface that abuts against the first flange portion of the coil bobbin to restrict movement of the coil bobbin inside the case; and a second locking portion that is formed to protrude toward the inner surface of the second end or a portion near the second end and has a second flat surface facing the first end, the second flat surface abutting against the second flange portion of the coil bobbin to restrict movement of the coil bobbin inside the case, wherein the second locking portion and the locking portion are formed integrally with the case. [Effects of the Invention]

[0011] Claim 1 From 6 According to the invention described in the above, the locking portion provided on the case restricts the movement of the coil bobbin, so that rattle of the coil bobbin can be suppressed without providing any other components such as a spacer.

[0012] Also Claim 1 to 6 According to the invention described in the above, rattle of the coil bobbin can be suppressed without reducing the attractive force when the electromagnet is energized.

[0013] Claim 7、8 According to the invention described above, by providing a locking portion and another locking portion at the first end or its vicinity and the second end or its vicinity of the case, respectively, the electromagnet can be assembled regardless of the orientation of the case, i.e., it is no longer necessary to identify the first end and the second end of the case before assembling the electromagnet. [Brief explanation of the drawings]

[0014] [Figure 1] 1 is a cross-sectional view of a direct acting solenoid according to a first embodiment of the present invention. [Figure 2] 3 is an enlarged cross-sectional view of a locking portion of a case and its surroundings in the direct-acting solenoid according to the first embodiment of the present invention. FIG. [Figure 3] FIG. 4 is a cross-sectional view of a direct acting solenoid according to a second embodiment of the present invention. [Figure 4] 10 is an enlarged cross-sectional view of a locking portion of a case and its surroundings in a direct-acting solenoid according to a second embodiment of the present invention. FIG. [Figure 5] FIG. 3 is an enlarged cross-sectional end view showing the detailed shape of the locking portion of the case in the direct-acting solenoid according to the first and second embodiments of the present invention. [Figure 6] FIG. 10 is an enlarged cross-sectional end view showing the detailed shape of a locking portion of a case in a direct-acting solenoid according to a third embodiment of the present invention. [Figure 7] FIG. 10 is an enlarged cross-sectional end view showing the detailed shape of a locking portion of a case in a direct-acting solenoid according to a fourth embodiment of the present invention. [Figure 8] 10 is a graph showing the relationship between thrust and the area ratio of the cross section in a direction perpendicular to the central axis of the end face of the first end of the case of a direct-acting solenoid according to a second embodiment of the present invention and the intermediate region closer to the intermediate portion than the engaging portion. [Figure 9] FIG. 2 is a schematic diagram showing an analytical model of the direct-acting solenoid according to the first embodiment of the present invention. [Figure 10] FIG. 10 is a schematic diagram showing an analytical model of a direct-acting solenoid according to a third embodiment of the present invention. [Figure 11] FIG. 10 is a schematic diagram showing an analytical model of a direct-acting solenoid according to a fifth embodiment of the present invention. [Figure 12] 4 is a table showing analysis results of the direct acting solenoids according to the first and second embodiments of the present invention and a comparative example. [Figure 13] FIG. 11 is an enlarged cross-sectional end view showing the detailed shape of a locking portion of a case in a direct-acting solenoid according to a fifth embodiment of the present invention. [Figure 14] FIG. 1 is a cross-sectional view of an electromagnet according to the prior art. DETAILED DESCRIPTION OF THE INVENTION

[0015] First, the electromagnet according to the present invention is not limited to direct-acting solenoids, but can also be applied to rotary solenoids, etc., as long as it has a case that functions as a coil bobbin and a yoke. Furthermore, it is even more preferably applicable if the movable magnetic pole and the first (one) end of the case are in contact. Furthermore, the first to fifth embodiments of the present invention described below are direct-acting solenoids that do not have a shaft, and in which the movable magnetic pole and spool are integrated, but the present invention can be applied regardless of the presence or absence of a spool, shaft, spring, etc.

[0016] Fig. 1 is a cross-sectional view of a direct-acting solenoid according to a first embodiment of the present invention. In Fig. 1, 10 denotes a case, 11 denotes a first end vicinity region, 12 denotes a locking portion, 17 denotes an intermediate region, 18 denotes a second end vicinity region, 19 denotes a thin-walled portion, 20 denotes a coil bobbin, 21 denotes a winding drum portion, 22a denotes a first flange portion, 22b denotes a third flange portion, 23 denotes a second flange portion, 23 denotes a coil, 30 denotes a fixed magnetic pole, 31 denotes a structural member, 32 denotes a protruding portion, 33 denotes an end cap / fixing member, 34 denotes a guide member, 35 denotes a spool-integrated movable magnetic pole, 36 denotes a movable magnetic pole portion, 37 denotes a protruding portion, 38 denotes a cylindrical portion, 39 denotes a flange portion, 40 denotes a spring receiver, 41 denotes a receiving seat portion, 41a denotes a protruding portion, 41b denotes a separation prevention portion, 42 denotes a filler ring, 43 denotes a spring, and 50 denotes a solenoid.

[0017] A solenoid 44 according to a first embodiment of the present invention will be described below. As shown in FIG. 1 , the solenoid 44 has a generally cylindrical appearance, with its outer shell formed by a case 10, an end cap / fixed member 33, and a guide member 34. The solenoid 44 is a direct-acting electromagnet in which a spool-integrated movable magnetic pole 35 moves linearly. Although not shown, the solenoid 44 is integral with a spool valve provided in a hydraulic circuit. In the solenoid 44, the spool-integrated movable magnetic pole 35, the fixed magnetic pole 30, the case 10, the coil 24, the coil bobbin 20, the protruding portion 32 of the structural member 31, and the cylindrical portion 38 of the guide member 34 all share the same central axis. Therefore, in the following description of the solenoid 44 according to the first embodiment, the term "center axis" refers to the central axis common to all of these elements. Furthermore, in the claims, the term "center axis" refers to the central axis common to the movable magnetic pole, the fixed magnetic pole, and the like. The spool-integrated movable magnetic pole 35 is configured to slide along the central axis and operate the flow path of a spool valve (not shown). In addition, the fixed magnetic pole 30, the spool-integrated movable magnetic pole 35, the guide member 34, the case 10, the end cap / fixing member 33, and the structural member 31 are all made of magnetic material and serve as a path for magnetic flux generated when current is passed through the coil 24.

[0018] As will be described in detail later, the solenoid 44 is characterized in that a locking portion 12 is provided in the first end vicinity region 11 to prevent the coil bobbin 20, around which the coil 24 is wound, from rattling inside the outer shell consisting of the case 10, the end cap / fixing member 33, and the guide member 34. In other words, to prevent the coil 24 from rattling due to vibrations or the like applied from outside the solenoid 44. In this specification, the "end vicinity region" in the first end vicinity region 11 refers to the range from the first end (the lower end of the case 10 in FIG. 1) to the point where the coil bobbin 20 makes contact with the first flange portion 22a. In addition, the "end vicinity region" in the second end vicinity region 18 refers to the range from the second end (the upper end of the case 10 in FIG. 1) to the point where the coil bobbin 20 makes contact with the second flange portion 23. In addition, the intermediate region 17 refers to the region between the first end vicinity region 11 and the second end vicinity region 18.

[0019] Furthermore, the coil bobbin 20 has a first flange 22a formed at a first end of the winding drum 21 and a second flange 23 formed at a second end of the winding drum 21. Additionally, the coil bobbin 20 has a third flange 22b formed at a position a predetermined distance inward from the first flange 22a of the winding drum 21. The first flange 22a, the second flange 23, and the third flange 22b are formed in a substantially circular plate shape and are arranged perpendicular to the central axis. The coil 24 is formed by winding a coil wire between the second flange 23 and the third flange 22b of the winding drum 21. The fixed magnetic pole 30 is formed in a substantially cylindrical shape, and a protrusion 32 of a structural member 31 is press-fitted into an opening on the end cap / fixing member 33 side. The spring 43 is provided with both ends abutting the protrusion 32 and the receiving seat 41 of the spring receiver 40, and constantly presses the spring receiver 40 toward the spool-integrated movable magnetic pole 35 side by its resilient force.

[0020] The spring receiver 40 is provided so that its protrusion 41a is slidably supported by the fixed magnetic pole 30 and faces the protrusion 37 of the spool-integrated movable magnetic pole 35, and its separation prevention portion 41b faces the protrusion 32 when inserted into the spring 43. The spool-integrated movable magnetic pole 35 has its movable magnetic pole portion 36 slidably supported by the cylindrical portion 38 of the guide member 34, and is attracted to and slides against the fixed magnetic pole 30 when current is applied to the coil 24. When the spool-integrated movable magnetic pole 35 is attracted to and slides against the fixed magnetic pole 30, the protrusion 37 formed on the movable magnetic pole portion 36 on the spring receiver 40 side abuts against and presses against the protrusion 41a of the spring receiver 40. Meanwhile, the spring 43 presses the spring receiver 40 toward the movable magnetic pole portion 36. Therefore, the spool-integrated movable magnetic pole 35 stops when the attractive force caused by the excitation of the coil 24 balances with the elastic force of the spring 43. The filler ring 42 connects the fixed magnetic pole 30 and the cylindrical portion 38 of the guide member 34, and prevents the hydraulic oil flowing in the hydraulic circuit from entering the coil 24 side.

[0021] Next, the case 10 of the solenoid 44 according to the first embodiment of the present invention will be described in detail. FIG. 2 is an enlarged cross-sectional view of the locking portion of the case and its surroundings in the direct-acting solenoid according to the first embodiment of the present invention. All reference numerals used in FIG. 2 are the same as those in FIG. 1. Furthermore, FIG. 5 is an enlarged cross-sectional end view showing the detailed shape of the locking portion of the case in the direct-acting solenoid according to the first and second embodiments of the present invention. In FIG. 5, 13 is the bottom surface, 14 is the inner inclined surface, 15 is the inner vertical surface, and 16 is the flat surface, and the other reference numerals are the same as those in FIG. 1. Note that the portion of the case 10 shown in FIG. 5 has exactly the same shape as the case in the direct-acting solenoid according to the second embodiment of the present invention, but the reference numerals of the case 50 will be described later.

[0022] 2 and 3, the case 10 of the solenoid 44 forms a locking portion 12 that protrudes toward the inner circumferential surface of the first end vicinity region 11. The locking portion 12 protrudes in an annular shape from the inner circumferential surface of the first end vicinity region 11, and a flat surface 16 abuts against the first flange portion 22a of the coil bobbin 20. The locking portion 12 is also formed so that the diameter at the inner vertical surface 15 is smaller than the outer diameter of the first flange portion 22a of the coil bobbin 20. Therefore, even if an external impact or vibration is applied to the solenoid 44, causing a force that would move the coil bobbin 20 toward the end cap / fixing member 33, the locking portion 12 restricts the movement of the coil bobbin 20, so the coil bobbin 20 is held in place.

[0023] Although the solenoid 44 according to this embodiment has the locking portion 12 formed in a circular ring shape, other configurations are also possible. For example, the locking portion 12 may not be completely circular, but may have a notch, and the first flange may have a protrusion that is inserted into the notch. This configuration facilitates assembling the solenoid with the coil bobbin facing a predetermined direction. Furthermore, the case may have two locking portions that are fan-shaped and arranged facing each other within an angle of less than 90° relative to the central axis, and the coil bobbin may have protrusions formed in two opposing regions of the edge of the first flange within an angle of less than 90° relative to the central axis. This configuration allows the coil bobbin to be removed from the case by rotating it 90°, but conversely, it is possible to prevent the coil bobbin from being removed from the case by rotating it 90° after inserting it into the case.

[0024] Next, a solenoid according to a second embodiment of the present invention will be described. FIG. 3 is a cross-sectional view of a direct-acting solenoid according to the second embodiment of the present invention. In FIG. 3, 24 denotes a coil, 25 denotes a coil bobbin, 26 denotes a winding drum, 27 denotes a first flange, 28 denotes a second flange, 29 denotes a coil, 45 denotes a movable magnetic pole, 45a denotes a through hole, 46 denotes a fixed magnetic pole, 46a denotes a small-diameter portion, 46b denotes a large-diameter portion, 47 denotes a guide member, 47a denotes a thin-walled portion, 47b denotes a thick-walled portion, 48 denotes an inclined surface, 49 denotes a solenoid, 50 denotes a case, 51 denotes a region near the first end, and 52 denotes a locking portion. FIG. 4 is an enlarged cross-sectional view of the locking portion of the case and its surroundings in a direct-acting solenoid according to the second embodiment of the present invention. All reference numerals used in FIG. 4 are the same as those in FIG. 3. Furthermore, Fig. 5 is an enlarged cross-sectional end view showing the detailed shape of the locking portion of the case in the direct-acting solenoid according to the first and second embodiments of the present invention. In Fig. 5, 53 is the bottom surface, 54 is the inner inclined surface, 55 is the inner vertical surface, 56 is the flat surface, 57 is the intermediate region, 58 is the region near the second end, and the other symbols are the same as those in Fig. 3.

[0025] As shown in FIG. 3 , a solenoid 49 according to a second embodiment of the present invention has a generally cylindrical appearance, with an outer shell formed by a case 50, a fixed magnetic pole 46, and a guide member 47. In the solenoid 49, the central axes of the case 50, the fixed magnetic pole 46, the guide member 47, the coil 24, and the coil bobbin 20 all coincide. Therefore, in the following description of the solenoid 49 according to the second embodiment, the term “central axis” refers to the central axis common to all of these. The guide member 47 has a thin portion 47a on the base end side and a thick portion 47b on the tip end side. The thin portion 47a accommodates and slidably supports the movable magnetic pole 45. A through-hole 45a is formed in the movable magnetic pole 45 along the central axis. The movable magnetic pole 45 is guided by the thin portion 47a of the guide member 47, allowing the movable magnetic pole 45 to slide up to an inclined surface 48, which is the boundary surface between the thin portion 47b and the guide member 47.

[0026] The fixed magnetic pole 46 has a small-diameter portion 46a that is inserted into the coil 24 and a large-diameter portion 46b that is press-fitted into the case 50. The coil bobbin 25 has a first flange portion 27 formed at a first end of the winding drum portion 26 and a second flange portion 28 formed at a second end of the winding drum portion 26. The first flange portion 27 and the second flange portion 28 are formed in a generally circular plate shape and are oriented perpendicular to the central axis. The coil 29 is formed by winding a coil wire around the winding drum portion 26 of the coil bobbin 25. As shown in FIGS. 4 and 5 , the case 50 of the solenoid 49 has an inner inclined surface 54 that is obliquely cut out from the lower portion of the inner circumferential surface of the locking portion 52. The case 50 is configured such that a width Tb of a bottom surface 53 that contacts the movable magnetic pole 45 and the thin-walled portion 47a of the guide member 47 is narrower than a width Ta of a cross section of the intermediate region 57 that is perpendicular to the central axis. This is because, as will be described later, the inventors have found through experiments and analysis that if the area of ​​bottom surface 53 is smaller than the area of ​​the cross section perpendicular to the central axis of intermediate region 57, the force attracting movable magnetic pole 45 toward fixed magnetic pole 46 increases when current is applied to coil 29.

[0027] Next, solenoids according to third and fourth embodiments of the present invention will be described. Fig. 6 is an enlarged cross-sectional end view showing the detailed shape of the locking portion of the case in a direct-acting solenoid according to the third embodiment of the present invention. In Fig. 6, 60 denotes the case, 61 denotes a first end vicinity region, 62 denotes the locking portion, 63 denotes an outer inclined surface, 64 denotes a bottom surface, 65 denotes an inner vertical surface, 66 denotes a flat surface, and 67 denotes an intermediate region. Fig. 7 is an enlarged cross-sectional end view showing the detailed shape of the locking portion of the case in a direct-acting solenoid according to a fourth embodiment of the present invention. In Fig. 7, 70 denotes the case, 71 denotes a first end vicinity region, 72 denotes the locking portion, 73 denotes a bottom surface, 74 denotes an inner lower vertical surface, 75 denotes an inner upper vertical surface, 76 denotes an upward flat surface, 77 denotes a downward flat surface, and 78 denotes an intermediate region. In the solenoids of the second and third embodiments, all components other than the case 60 and the case 70 are the same as those of the solenoid 44 of the first embodiment, so a description of the components other than the case 60 and the case 70 will be omitted.

[0028] As shown in FIG. 6 , a case 60 of a solenoid according to a third embodiment of the present invention has a locking portion 62 formed in a first end vicinity region 61, similar to the locking portion 52. The bottom surface 64 of the locking portion 62 has a width Tc that is smaller than the area of ​​a cross section perpendicular to the central axis of the intermediate region 67. Unlike the locking portion 52, which has an inner inclined surface 54 obliquely cut out from the lower portion of the inner circumferential surface, the locking portion 62 has an outer inclined surface 63 obliquely cut out from the lower portion of the outer circumferential surface, and an inner vertical surface 65 on the inner circumferential surface side. As will be described later, the obliquely cut-out portion on the lower side of the locking portion can achieve substantially the same effect whether it is on the inner circumferential surface side or the outer circumferential surface side. The flat surface 66 of the locking portion 62 is provided to abut against the first flange portion 27 of the coil bobbin 25, similar to the flat surface 56 of the locking portion 52. The parts of the case 60 that are not shown in the figure have the same configuration as the case 50, and therefore the description thereof will be omitted.

[0029] As shown in FIG. 7 , a case 70 of a solenoid according to a fourth embodiment of the present invention has a locking portion 72 formed in a first end vicinity region 71, similar to the locking portion 52. The bottom surface 73 of the locking portion 72 has a width Td that is smaller than the area of ​​a cross section perpendicular to the central axis of the intermediate region 78. Unlike the locking portions 52 and 62, which have obliquely cutouts in the lower portions of the inner or outer circumferential surface, the locking portion 72 has an inner lower vertical surface 74 that rises vertically from the lower end of the inner circumferential surface and protrudes from the upper end of the inner lower vertical surface 74 toward the central axis of the case 70. The locking portion 72 is also formed so as to be surrounded by two flat surfaces, an upward flat surface 76 and a downward flat surface 77, and an inner upper vertical surface 75. Thus, substantially the same effect can be achieved even when the locking portion does not have an inclined surface cut out obliquely. The upward flat surface 76 is provided so as to abut against the first flange portion 22a of the coil bobbin 20, similar to the flat surface 56 of the locking portion 52. Note that portions of the case 70 not shown have the same configuration as the case 50, and therefore description thereof will be omitted.

[0030] Next, we will explain the results of magnetic field analysis and the like of solenoids according to second to fourth embodiments of the present invention. FIG. 8 is a graph showing the relationship between thrust and the area ratio of the end face of the first end of the case of a direct-acting solenoid according to the second embodiment of the present invention to the central axis of an intermediate region closer to the intermediate region than the locking portion, as viewed in a direction perpendicular to the central axis. FIG. 9 is a schematic diagram showing an analytical model of a direct-acting solenoid according to the first embodiment of the present invention. In FIG. 9, 80 denotes a case member, 81 denotes a locking portion, 82 denotes a bottom surface, 83 denotes an end cap member, 84 denotes a magnetic pole member, and 85 denotes a coil. FIG. 10 is a schematic diagram showing an analytical model of a direct-acting solenoid according to a third embodiment of the present invention. In FIG. 10, 86 denotes a locking portion, 87 denotes a bottom surface, and other reference numerals are the same as those in FIG. 9. FIG. 11 is a schematic diagram showing an analytical model of a direct-acting solenoid according to a fourth embodiment of the present invention. In Fig. 11, 88 denotes a locking portion, 89 denotes a bottom surface, and other reference numerals denote the same as those in Fig. 9. In addition, Fig. 12 is a table showing the analysis results of the direct-acting solenoids according to the first and second embodiments of the present invention, as well as a comparative example. Fig. 13 is an enlarged cross-sectional end view showing the detailed shape of the locking portion of the case in the direct-acting solenoid according to the fourth embodiment of the present invention. In Fig. 13, 90 denotes the case, 91 denotes the first end vicinity region, 92 denotes the locking portion, 93 denotes the bottom surface, 94 denotes the inner vertical surface, 95 denotes the flat surface, and 96 denotes the intermediate region.

[0031] As mentioned in the description of the solenoid according to the second embodiment of the present invention, in order to improve thrust (attraction force), for example, the area of ​​the bottom surface 53 of the case 50 is formed smaller than the area of ​​the cross section perpendicular to the central axis of the intermediate region 57. However, in applications requiring only a relatively small attractive force compared to the size of the solenoid, it is also possible to configure the case 90 of the direct-acting solenoid according to the fifth embodiment. That is, the case 90 has a locking portion 92 formed in a first end vicinity region 91. The locking portion 92 is formed so as to be surrounded by two flat surfaces, a flat surface 95 and a bottom surface 93, and an inner vertical surface 94. The flat surface 95 is provided so as to abut against the first flange portion 27 of the coil bobbin 25, similar to the flat surface 56 of the locking portion 52. Note that portions of the case 90 not shown in the drawings have the same configuration as the case 50, and therefore will not be described here.

[0032] The case 90 of the solenoid according to the fifth embodiment does not have a notch cut out at the bottom, as in the solenoids according to the second and third embodiments, nor does it have a step formed to reduce the area of ​​the bottom, as in the solenoid according to the third embodiment. Therefore, the width Te of the bottom surface 93 of the locking portion 92 is significantly larger than the width Ta of a cross section perpendicular to the central axis of the intermediate region 96, and the area of ​​the bottom surface 93 is significantly larger than the area of ​​the cross section perpendicular to the central axis of the intermediate region 96. As described above, the case 90 of the solenoid according to the fifth embodiment has a lower thrust than the case of the solenoid according to the second embodiment, but the number of times the base material of the case is cut is reduced, so the manufacturing cost of the solenoid can be somewhat lower than in the other embodiments.

[0033] Next, the results of magnetic field analysis performed by the inventors on solenoids according to the second, third, and fifth embodiments will be described. FIG. 9 corresponds to the solenoid according to the first embodiment, in which case member 80, end cap member 83, and magnetic pole member 84 are arranged to surround coil 85, and locking portion 81 and bottom surface 82 correspond to locking portion 12 and bottom surface 13 of case 10. FIG. 10 corresponds to the solenoid according to the second embodiment, in which case member 80, end cap member 83, and magnetic pole member 84 are arranged to surround coil 85, and locking portion 86 and bottom surface 87 correspond to locking portion 62 and bottom surface 64 of case 60. FIG. 11 corresponds to the solenoid according to the fourth embodiment, in which case member 80, end cap member 83, and magnetic pole member 84 are arranged to surround coil 85, and locking portion 88 and bottom surface 89 correspond to locking portion 92 and bottom surface 93 of case 90. In the models of FIGS. 9 to 11, the configurations of parts that are not relevant to the present invention or are small are simplified.

[0034] FIG. 8 is a graph showing the relationship between the area of ​​the bottom surface 87 and the area of ​​the cross section perpendicular to the central axis of the case member 80. The graph analyzes the magnetic attraction force in the unsaturated state, saturated state, and intermediate states of the magnetic circuit. The analysis results show that the highest magnetic attraction force is obtained when the area of ​​the bottom surface 87 is 0.6 to 0.7 times the area of ​​the cross section perpendicular to the central axis of the case member 80 in the unsaturated state of the magnetic circuit, and when the area is 0.7 to 0.9 times the area of ​​the cross section perpendicular to the central axis of the case member 80 in the saturated and intermediate states. Furthermore, it was found that the magnetic attraction force gradually decreases as the area of ​​the bottom surface 87 is increased relative to the area of ​​the cross section perpendicular to the central axis of the case member 80. Considering the above, it can be said that it is most advantageous to set the area of ​​the bottom surface 87 to 0.7 to 0.8 times the area of ​​the cross section perpendicular to the central axis of the case member 80 in order to obtain a high magnetic attraction force regardless of the saturated state. That is, in the direct acting solenoid 49 according to the second embodiment of the present invention, the locking portion 52 of the case 50 restricts the movement of the coil bobbin 25, and also has the effect of improving the attractive force to the movable magnetic pole 45. Furthermore, according to the inventor's knowledge, it has been found that the same effect can be obtained even if the configuration is different from that of the solenoid 49, as long as the movable magnetic pole is configured to directly approach and move away from the case.

[0035] Furthermore, when comparing the cases of the direct-acting solenoids according to the second, third, and fifth embodiments of the present invention, it was found that the solenoid according to the first embodiment, which has an inclined surface formed on the inner circumferential surface (inner chamfering), is slightly more advantageous than the solenoid according to the third embodiment, which has an inclined surface formed on the outer circumferential surface (outer chamfering), and that the attractive force of the solenoid according to the fifth embodiment, which has no inclined surface (no chamfering), is clearly lower. Furthermore, from the results of other prototypes and experiments by the inventors, it was found that narrowing the area of ​​the bottom of the case by means other than forming an inclined surface, as in the solenoid according to the fourth embodiment of the present invention, is also effective in improving attractive force.

[0036] As described above, in the electromagnets according to the first to fifth embodiments of the present invention, the locking portions 12 to 92 provided on the cases 10 to 60 restrict movement of the coil bobbin 20 or 25, thereby suppressing rattle of the coil bobbin 20 or 25 without providing any additional components such as spacers. Also, in the electromagnets according to the second to fourth embodiments of the present invention, the area of ​​the bottom surfaces 53 to 73 of the locking portions 52 to 72 is smaller than the area of ​​the cross section perpendicular to the central axis of the intermediate regions 57 to 78, thereby suppressing rattle of the coil bobbin 25 without reducing the attractive force (thrust). Furthermore, in the electromagnets according to the first to fifth embodiments of the present invention, by providing a locking portion and another locking portion at the first end or its vicinity and the second end or its vicinity of the case, respectively, the electromagnet can be assembled regardless of the orientation of the case. In other words, it is not necessary to distinguish between the first end and the second end of the case before assembling the electromagnet.

[0037] The present invention is not limited to the above-described contents, and various configurations are possible as long as they do not deviate from the scope of the claims, such as applying the solenoid according to each embodiment of the present invention to a rotary solenoid. [Explanation of symbols]

[0038] 10 cases 11 first end vicinity region 12 Locking part 13 Bottom 14 Inner slope 15 Inner vertical plane 16 flat surface 17 Intermediate area 18 Second end vicinity region 19 Thin section 20 Coil bobbin 21 Winding body 22a first flange portion 22b Third flange portion 23 Second flange 24 coils 25 Coil bobbin 26 Winding body 27 First flange portion 28 Second flange 29 Coil 30 fixed magnetic pole 31 Structural members 32 Protrusion 33 End cap and fixing member 34 Guide member 35 Spool-integrated moving pole 36 Movable magnetic pole part 37 Protrusion 38 Cylindrical section 39 Flange 40 Spring holder 41 Receiving seat 41a Protrusion 41b Anti-detachment part 42 Filler Ring 43 Spring 44 Solenoid 45 Moving magnetic pole 45a through hole 46 fixed magnetic pole 46a Small Diameter 46b Large diameter part 47 Guide member 47a Thin section 47b Thick part 48 Slope 49 Solenoid 50 cases 51 first end vicinity region 52 Locking part 53 bottom 54 Inner slope 55 Inner vertical plane 56 Flat surface 57 Intermediate area 58 Second edge vicinity region 60 cases 61 first end vicinity region 62 Locking part 63 Outer slope 64 bottom 65 Inner vertical plane 66 Flat surface 67 Intermediate area 70 cases 71 first end vicinity region 72 Locking part 73 Outer slope 74 Inner lower vertical plane 75 Medial upper vertical plane 76 Upward flat surface 77 Downward-facing flat surface 78 Intermediate area 80 Case material 81 Locking part 82 bottom 83 End cap member 84 Magnetic pole members 85 coils 86 Locking part 87 bottom 88 Locking part 89 bottom 90 cases 91 first end vicinity region 92 Locking part 93 bottom 94 Inner vertical plane 95 Flat surface 96 Intermediate area 100 solenoid 101 frames 102a Legs 102a Legs 102c bottom 102d Protrusion 103 Coil bobbin 103a Flange 104 Subframe 104a Through hole 105 Excitation coil 106 Cylinder 106a Flange part 107 Sealing material 108 moving core 109 Air Damper Room

Claims

1. a coil bobbin including a winding drum formed in a substantially cylindrical shape, a first flange provided at a first end portion on one side of a central axis of the winding drum, and a second flange provided at a second end portion on the other side of the central axis of the winding drum; a coil formed by winding a coil wire around the winding drum of the coil bobbin; An electromagnet made of a magnetic material, formed into a substantially cylindrical shape, and having a case in which the coil bobbin and the coil are disposed, the case has a locking portion formed so as to protrude toward the inner peripheral surface of the first end or a portion near the first end, and has a flat surface facing the second end, the flat surface abutting against the first flange portion of the coil bobbin to restrict movement of the coil bobbin inside the case; an end cap made of a magnetic material and provided on the coil bobbin so as to abut against a first end surface of the case from one side of the central axis, The electromagnet is characterized in that the case abuts against the end cap only at the first end surface, and the area of ​​the first end surface is smaller than the cross-sectional area of ​​an intermediate region closer to the intermediate portion, which is on the other side of the central axis than the engaging portion, in a direction perpendicular to the central axis.

2. a coil bobbin including a winding drum formed in a substantially cylindrical shape, a first flange provided at a first end portion on one side of a central axis of the winding drum, and a second flange provided at a second end portion on the other side of the central axis of the winding drum; a coil formed by winding a coil wire around the winding drum of the coil bobbin; An electromagnet made of a magnetic material, formed into a substantially cylindrical shape, and having a case in which the coil bobbin and the coil are disposed, the case has a locking portion formed so as to protrude toward the inner peripheral surface of the first end or a portion near the first end, and has a flat surface facing the second end, the flat surface abutting against the first flange portion of the coil bobbin to restrict movement of the coil bobbin inside the case; a member made of a magnetic material for generating a magnetic flux path together with the case when current is applied to the coil; The electromagnet is characterized in that the area of ​​the surface of the case that contacts the member made of magnetic material on one side of the central axis relative to the coil bobbin is smaller than the cross-sectional area in a direction perpendicular to the central axis of an intermediate region closer to the intermediate portion, which is on the other side of the central axis than the engaging portion.

3. The member made of the magnetic material is A guide member; a movable magnetic pole guided in the direction of the central axis by the guide member; and the guide member and the movable magnetic pole contact a bottom surface of the case from one side of the central axis with respect to the coil bobbin, the case is in contact with the member made of magnetic material only at the bottom surface, 3. The electromagnet according to claim 2, wherein the area of ​​the bottom surface is smaller than the cross-sectional area of ​​an intermediate region closer to the intermediate portion on the other side of the central axis than the locking portion, in a direction perpendicular to the central axis.

4. a coil bobbin including a winding drum formed in a substantially cylindrical shape, a first flange provided at a first end portion on one side of a central axis of the winding drum, and a second flange provided at a second end portion on the other side of the central axis of the winding drum; a coil formed by winding a coil wire around the winding drum of the coil bobbin; An electromagnet made of a magnetic material, formed into a substantially cylindrical shape, and having a case in which the coil bobbin and the coil are disposed, the case has a locking portion formed so as to protrude toward the inner peripheral surface of the first end or a portion near the first end, and has a flat surface facing the second end, the flat surface abutting against the first flange portion of the coil bobbin to restrict movement of the coil bobbin inside the case; an end cap made of a magnetic material and provided on the coil bobbin so as to abut against a first end surface of the case from one side of the central axis, The electromagnet is characterized in that a gap is formed between the case and the end cap inside the first end face, and the area of ​​the first end face is smaller than the cross-sectional area in a direction perpendicular to the central axis of an intermediate region closer to the intermediate portion, which is on the other side of the central axis than the engaging portion.

5. A structural member made of a magnetic material and disposed inside the case, The electromagnet according to claim 4 , wherein the case defines the gap between the end cap and the structural member on the inside of the first end face.

6. a coil bobbin including a winding drum formed in a substantially cylindrical shape, a first flange provided at a first end portion on one side of a central axis of the winding drum, and a second flange provided at a second end portion on the other side of the central axis of the winding drum; a coil formed by winding a coil wire around the winding drum of the coil bobbin; An electromagnet made of a magnetic material, formed into a substantially cylindrical shape, and having a case in which the coil bobbin and the coil are disposed, the case has a locking portion formed so as to protrude toward the inner peripheral surface of the first end or a portion near the first end, and has a flat surface facing the second end, the flat surface abutting against the first flange portion of the coil bobbin to restrict movement of the coil bobbin inside the case; an end cap made of a magnetic material and provided on the coil bobbin so as to abut against a first end surface of the case from one side of the central axis, the locking portion forms the first end surface and an inclined surface that is continuous with the first end surface and that cuts out an inner circumferential surface or an outer circumferential surface of the case obliquely with respect to the central axis, An electromagnet, characterized in that the area of ​​the first end face is smaller than the cross-sectional area in a direction perpendicular to the central axis of an intermediate region closer to the intermediate portion, which is on the other side of the central axis than the engaging portion.

7. Further comprising a fixed magnetic pole inserted into the coil bobbin, the case further comprises a second locking portion that is formed so as to protrude toward the inner peripheral surface of the second end or a portion near the second end and that has a second flat surface facing the first end, the second flat surface abutting against the second flange portion of the coil bobbin to restrict movement of the coil bobbin inside the case, 7. The electromagnet according to claim 1, wherein the second locking portion and the locking portion are formed integrally with the case.

8. A coil bobbin having a winding body formed in an approximately cylindrical shape, a first flange portion provided at a first end of the winding body, and a second flange portion provided at a second end of the winding body; a coil formed by winding a coil wire around the winding drum of the coil bobbin; a case made of a magnetic material and formed into a substantially cylindrical shape, the case having the coil bobbin and the coil disposed therein; An electromagnet having a fixed magnetic pole inserted into the coil bobbin, The case is a locking portion formed so as to protrude toward the inner peripheral surface of the first end or a portion near the first end, and having a flat surface facing the second end, the flat surface abutting against the first flange portion of the coil bobbin to restrict movement of the coil bobbin inside the case; a second locking portion formed so as to protrude toward the inner peripheral surface of the second end or a portion near the second end, and having a second flat surface facing the first end, the second flat surface abutting against the second flange portion of the coil bobbin to restrict movement of the coil bobbin inside the case; The electromagnet, wherein the second locking portion and the locking portion are integrally formed with the case.

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