JP6972483B2 - solenoid - Google Patents

Description

The present invention relates to a solenoid, and more particularly to a solenoid having a linear motion type configuration having both flat type and conical type characteristics.

The direct acting type solenoid can be roughly classified into a flat type and a conical type depending on the shape of the magnetic pole. In the flat type, the portions of the fixed magnetic poles and the movable magnetic poles facing each other are formed flat, and in the conical type, these portions are formed so as to form irregularities. The features of these two types of solenoids will be described below. FIG. 17 is a cross-sectional view showing a flat type solenoid according to the prior art. In FIG. 17, 200 is a solenoid, 201 is a fixed magnetic pole, 202 is a facing portion, 203 is a movable magnetic pole, 204 is a facing portion, 205 is a case, and 206 is a coil. Further, FIG. 18 is a cross-sectional view showing a conical type solenoid according to the prior art. In FIG. 18, 210 is a solenoid, 211 is a fixed magnetic pole, 212 is a facing portion, 213 is a movable magnetic pole, 214 is a facing portion, 215 is a case, and 216 is a coil.

First, a conventional example of a flat type solenoid will be described. FIG. 17 is a flat type solenoid disclosed in Japanese Patent Application Laid-Open No. 2008-4742. The solenoid 200 is provided with a movable magnetic pole 203 so as to slide in the hollow portion of the coil 206 provided inside the case 205, and further provided with a fixed magnetic pole 201 so as to close one end of the case 205 and the coil 206. There is. The facing portion 202 of the fixed magnetic pole 201 and the facing portion 204 of the movable magnetic pole 203 are formed as a central axis of the movable magnetic pole 203, that is, a flat surface orthogonal to the sliding direction of the movable magnetic pole 203. When the facing portions are flat surfaces in this way, the magnetic flux flowing between them flows substantially parallel to the central axis of the movable magnetic pole 203. Therefore, the magnetic force generated between the fixed magnetic pole 201 and the movable magnetic pole 203 is substantially parallel to the central axis of the movable magnetic pole 203. In other words, most of the magnetic force generated by energizing the coil 206 contributes to the thrust that attracts the movable magnetic pole 203 to the fixed magnetic pole 201.

Next, a conventional example of a conical solenoid will be described. FIG. 18 is a conical solenoid disclosed in Japanese Patent Application Laid-Open No. 2004-63825. The solenoid 210 is provided with a movable magnetic pole 213 so as to slide in the hollow portion of the coil 216 provided inside the case 215, and further provided with a fixed magnetic pole 211 so as to close one end of the case 215 and the coil 216. There is. The facing portion 212 of the fixed magnetic pole 211 is formed as a convex portion in the shape of a truncated cone, and protrudes toward the facing portion 214 of the movable magnetic pole 213. On the other hand, the facing portion 214 of the movable magnetic pole 213 is formed as a truncated cone-shaped concave portion and meshes with the facing portion 212 which is a convex portion, that is, has the same inclination angle with respect to the central axis of the movable magnetic pole 213. It is formed on a tapered surface. Therefore, the magnetic force generated between the fixed magnetic pole 211 and the movable magnetic pole 213 is a tapered surface in which the facing portions thereof are inclined with respect to the central axis of the movable magnetic pole 213, so that when the movable magnetic pole approaches the fixed magnetic pole. In addition, the ratio of the magnetic force that attracts the movable magnetic pole to the side instead of the front is higher than that of the flat type solenoid. Further, the ratio of the magnetic force components in the orthogonal directions increases as the facing portion 212 and the facing portion 214 approach each other. Further, since the facing portions are tapered surfaces, the magnetic gap between the facing portion 212 and the facing portion 214 when the coil 216 is not energized is smaller than that of the flat type.

Looking at the flat type and conical type solenoids described above from the thrust characteristics, the flat type provides a strong thrust, while the conical type has a relatively small thrust. On the other hand, in the flat type, if the magnetic gap between the fixed magnetic pole and the movable magnetic pole is longer than a certain length, the thrust at the start of energization of the coil becomes very small, but in the conical type, the thrust is large. It does not change. As described above, the thrust of the flat type solenoid is characterized in that it rapidly increases from the start to the end of the movable magnetic pole. On the contrary, in the conical solenoid, a thrust of a certain magnitude can be obtained even when the coil is energized, but the thrust does not increase sharply even if the movable magnetic pole approaches the fixed magnetic pole.

Therefore, the flat solenoid is suitable for applications where the required stroke length is relatively short, for example, 3 mm. Further, since the thrust is very large when the movable magnetic pole is very close to the fixed magnetic pole or when the movable magnetic pole is attracted to the fixed magnetic pole, the load is very large or the movable magnetic pole is the fixed magnetic pole. It can be said that it is suitable when it is required to strongly maintain the state of being adsorbed on the surface. On the other hand, the conical solenoid is suitable for applications in which the required stroke length is, for example, 6 mm or more, which is relatively long. It is also suitable for applications that require almost constant thrust and applications that require quietness.

By the way, depending on the device to which the solenoid is mounted, the advantages of the flat type and the advantages of the conical type may be required at the same time, such as a long stroke length and at the same time being able to strongly hold the state in which the movable magnetic pole is attracted to the fixed magnetic pole. be. In such a case, for example, a large conical solenoid is attached and a large current is passed through the coil so that a large thrust can be obtained. However, it cannot be said to be a preferable solution because it causes secondary problems such as a considerably larger power consumption than the case of using a flat solenoid and an increase in the area required for mounting the solenoid.

Japanese Unexamined Patent Publication No. 2008-4742 Japanese Unexamined Patent Publication No. 2004-63825

An object of the present invention is to provide a solenoid having the features of both a flat type solenoid and a conical type solenoid in order to solve the above problems.

The invention according to claim 1 is made of a magnetic material and has a case formed in a substantially cylindrical shape having openings at both ends, and a hollow portion provided inside the case and extending along a central axis. A coil bobbin having a formed winding body portion and flanges provided at both ends of the winding body portion, and a coil formed by winding a coil wire around the coil bobbin are formed in a substantially annular plate shape. A main body provided so as to close one of the openings of the case, an opening formed in the center of the main body, and the other opening side of the case from the peripheral region of the opening. It is formed into a fixed magnetic pole having a convex portion protruding toward the coil, a substantially cylindrical shape, a substantially bottomed cylindrical shape, or a substantially cylindrical shape, and is arranged so as to be inserted through the winding body portion of the coil bobbin. A movable magnetic pole provided so as to be attracted to and move by the fixed magnetic pole when energized is formed in a substantially annular plate shape, and between the coil bobbin and the fixed magnetic pole, the case and the case. Auxiliary magnetic poles arranged so that a magnetic gap is formed between the fixed magnetic pole and the magnetic gap between the case and the magnetic gap is smaller than the magnetic gap between the fixed magnetic pole and the fixed magnetic pole. It is a solenoid characterized by having.

The invention according to claim 2 is the invention according to claim 1, wherein the auxiliary magnetic pole is other than the entire region of the inner peripheral surface of the opening formed in the center near the fixed magnetic pole, or the vicinity of the lower end portion. The solenoid is characterized in that the portion is formed on a tapered surface or a stepped surface whose diameter gradually increases toward the fixed magnetic pole side.

The invention according to claim 3 is the invention according to claim 1 or 2, wherein the auxiliary magnetic pole gradually expands toward the coil bobbin side in a region of the inner peripheral surface of the opening near the coil bobbin. It is a solenoid characterized by being formed on a tapered surface or a stepped surface having a diameter.

The invention according to claim 4 is the invention according to any one of claims 1 to 3, wherein the auxiliary magnetic pole has an inner peripheral side edge region on the coil bobbin side protruding toward the coil bobbin side. It is a solenoid characterized by being formed in such a manner.

The invention according to claim 5 is the invention according to claim 4, wherein the auxiliary magnetic pole has an inner peripheral side edge region on the coil bobbin side entering the inside of the winding body portion of the coil bobbin and the coil bobbin side. The solenoid is characterized in that a region other than the inner peripheral side edge region of the coil bobbin is provided so as to be in contact with the flange of one of the coil bobbins.

The invention according to claim 6 is the invention according to any one of claims 1 to 5, further comprising a non-magnetic material and arranged between the auxiliary magnetic pole and the fixed magnetic pole. The solenoid is characterized by having a spacer, and a fixing pin that penetrates the auxiliary magnetic pole, the spacer, and the fixed magnetic pole, and fixes the auxiliary magnetic pole and the spacer to the fixed magnetic pole.

The invention according to claim 7 is the invention according to any one of claims 1 to 6, further fixed to the movable magnetic pole and extended along the central axis of the movable magnetic pole. A solenoid characterized by having a provided shaft and a bearing that is fitted to the opening of the fixed magnetic pole and supports the sliding of the shaft.

According to the first aspect of the invention, the auxiliary magnetic pole is more movable than the fixed magnetic pole when the auxiliary magnetic pole is located between the coil bobbin and the fixed magnetic pole, that is, when the movable magnetic pole is located far from the fixed magnetic pole. In addition to being placed closer to the magnetic poles, there is a magnetic gap between the auxiliary magnetic poles and the case and fixed magnetic poles, and the magnetic gap between the auxiliary magnetic poles and the case is the magnetic gap between the auxiliary magnetic poles and the fixed magnetic poles. Since it is smaller than, the reluctance between the auxiliary magnetic pole and the case is smaller than the reluctance between the movable magnetic pole and the fixed magnetic pole. Therefore, while the coil is energized, the magnetic flux flowing from the movable magnetic pole to the fixed magnetic pole via the auxiliary magnetic pole is very small. Further, when the coil is energized, that is, when the movable magnetic pole starts to slide, the magnetic gap between the movable magnetic pole and the auxiliary magnetic pole is relatively small, so that the magnetic flux mainly flows from the movable magnetic pole to the case via the auxiliary magnetic pole. .. When the movable magnetic pole approaches the fixed magnetic pole, the magnetic gap between the movable magnetic pole and the fixed magnetic pole becomes smaller, and the magnetoresistance between the movable magnetic pole and the fixed magnetic pole becomes smaller. It flows to the case and does not flow much to the auxiliary magnetic pole. That is, the auxiliary magnetic pole functions for a while from the start of sliding of the movable magnetic pole, and when the movable magnetic pole approaches the fixed magnetic pole, the auxiliary magnetic pole does not function very much. Therefore, the first half of the operation of the movable magnetic pole is a solenoid having the characteristics of the conical type, and the latter half of the operation of the movable magnetic pole is the solenoid having the characteristics of the flat type.

According to the second aspect of the present invention, the entire area of the inner peripheral surface of the opening formed in the center near the fixed magnetic flux, or a portion other than the vicinity of the lower end portion, gradually expands in diameter toward the fixed magnetic flux side. Since it is formed on a tapered or stepped surface, it does not adversely affect the region of the path of the magnetic flux flowing from the movable magnetic pole to the case via the auxiliary magnetic pole, and the magnetism between the auxiliary magnetic pole and the fixed magnetic pole is not adversely affected. The gap can be increased.

According to the third aspect of the present invention, since the region of the inner peripheral surface of the opening of the auxiliary magnetic pole near the coil bobbin is made into a tapered surface or a stepped surface whose diameter gradually increases toward the coil bobbin side, the coil bobbin on the inner peripheral surface is formed. The area closer to the movable magnetic pole is an inclined surface with respect to the central axis of the movable magnetic pole. Therefore, in the magnetic force generated by the magnetic flux flowing between this region and the movable magnetic pole, the proportion of the component parallel to the central axis of the movable magnetic pole becomes larger, and the thrust at the start of sliding of the movable magnetic pole can be further increased. can.

According to the fourth aspect of the present invention, since the inner peripheral side edge region of the auxiliary magnetic pole on the coil bobbin side is projected toward the coil bobbin side, the magnetic gap between the auxiliary magnetic pole and the movable magnetic pole can be reduced and the movable magnetic pole can be moved. The thrust at the start of sliding of the magnetic pole can be further increased.

According to the fifth aspect of the present invention, the inner peripheral side edge region on the coil bobbin side of the auxiliary magnetic pole enters the inside of the winding body portion of the coil bobbin, and the region other than the inner peripheral side margin region on the coil bobbin side is one of the coil bobbins. Since it is in contact with the flange, the auxiliary magnetic pole can be used as a holding member for the coil bobbin. Further, by eliminating the unnecessary space between the auxiliary magnetic pole and the coil bobbin, it is possible to contribute to the miniaturization of the solenoid.

According to the invention of claim 6, a spacer made of a non-magnetic material is provided between the fixed magnetic pole and the auxiliary magnetic pole, and the auxiliary magnetic pole and the spacer are fixed to the fixed magnetic pole by a fixing pin, so that the auxiliary magnetic pole and the fixed magnetic pole are fixed. And the magnetic gap between the case and the case can be set accurately.

According to the invention of claim 7, since the periphery of the opening of the fixed magnetic pole is a convex portion, the thickness (length) sufficient to fit the bearing supporting the shaft in the direction of the central axis of the movable magnetic pole. It can be secured.

It is sectional drawing in the energized state of the solenoid which concerns on 1st Embodiment of this invention. FIG. 5 is a sectional view taken along line AA in an energized state of the solenoid according to the first embodiment of the present invention. It is sectional drawing in the non-energized state of the solenoid which concerns on 1st Embodiment of this invention. A fixed magnetic pole of a solenoid according to the first aspect of the present invention is shown, (a) is a front view, (b) is a plan view, and (c) is a sectional view taken along line BB. A spacer of the solenoid according to the first aspect of the present invention is shown, (a) is a front view, (b) is a plan view, and (c) is a sectional view taken along the line CC. The auxiliary magnetic pole of the solenoid according to the first aspect of the present invention is shown, (a) is a front view, and (b) is a plan view. The auxiliary magnetic pole of the solenoid according to the first aspect of the present invention is shown, (c) is a DD diagram, and (b) is a sectional view taken along line EE. The components of the solenoid according to the first aspect of the present invention are shown, (a) is a plan view of a movable magnetic pole, (b) is a sectional view taken along line FF of the movable magnetic pole, and (c) is a plan view of a shaft. d) is a front view of the shaft, (e) is a front view of the fixing pin, and (f) is a bottom view of the fixing pin. A case of a solenoid according to the first aspect of the present invention is shown, (a) is a plan view, and (b) is a sectional view taken along the line GG. It is a perspective view (1) which shows the assembly procedure of the solenoid which concerns on 1st Embodiment of this invention. It is a perspective view (2) which shows the assembly procedure of the solenoid which concerns on 1st Embodiment of this invention. It is sectional drawing (1) which shows the flow of the magnetic flux in the solenoid which concerns on 1st Embodiment of this invention. It is sectional drawing (2) which shows the flow of the magnetic flux in the solenoid which concerns on 1st Embodiment of this invention. It is a partial cross-sectional view which shows the solenoid which concerns on 2nd to 4th Embodiment of this invention, (a) is the partial sectional view of the solenoid which concerns on 2nd Embodiment, (b) is the 3rd Embodiment. A partial cross-sectional view of the solenoid according to the embodiment, (c) is a partial cross-sectional view of the solenoid according to the fourth embodiment. It is a partial cross-sectional view which shows the solenoid which concerns on 5th and 6th Embodiment of this invention, (d) is the partial sectional view of the solenoid which concerns on 5th Embodiment, (e) is 6th Embodiment. It is a partial cross-sectional view of the solenoid which concerns on the form. It is a graph which shows the thrust characteristic in the solenoid which concerns on 1st and 2nd Embodiment of this invention. It is sectional drawing which shows the flat type solenoid which concerns on the prior art. It is sectional drawing which shows the conical type solenoid which concerns on the prior art.

The solenoid according to the first embodiment of the present invention will be described. First, in the following description, the "tip side" is defined as the side where the protruding portion 58 of the shaft 56 is provided, that is, the lower side of FIGS. 1 to 3 and 10 to 15, and the "base" of the solenoid is defined. The "end side" is defined as the side of the case 60 where the small diameter portion 62 is provided, that is, the upper side of FIGS. 1 to 3 and FIGS. 10 to 15. Further, the "central axis" is defined as the central axis of the movable magnetic pole 50. In the solenoid according to each embodiment described below, the central axis of the movable magnetic pole 50 and the central axis of the shaft 56 and the case 60 coincide with each other.

FIG. 1 is a cross-sectional view of the solenoid according to the first embodiment of the present invention in an energized state. In FIG. 1, 10 is a solenoid, 20 is an auxiliary magnetic pole, 22 is a convex portion, 24b is a tapered surface on the tip side, 30 is a fixed magnetic pole, 31 is a main body portion, 32 is a convex portion, 40 is a spacer, 41 is a main body portion, 42. Is a convex part, 50 is a movable magnetic pole, 51 is a main body part, 52 is a bottom part, 54 is a hollow part, 56 is a shaft, 57 is a fitting part, 58 is a protruding part, 60 is a case, 61 is a main body part, and 62 is a small diameter. Section, 63 is a stepped portion, 70 is a coil bobbin, 71 is a winding body portion, 72 is a first flange portion, 73 is a second flange portion, 74 is a third flange portion, 75 is a coil, and 76 and 77 are oil-free bearings. 78 is a spacer. Further, FIG. 2 is a sectional view taken along line AA in an energized state of the solenoid according to the first embodiment of the present invention. In FIG. 2, 79a and 79b are fixed pins, and the other reference numerals are the same as those in FIG. Further, FIG. 3 is a cross-sectional view of the solenoid according to the first embodiment of the present invention in a non-energized state. The reference numerals used in FIG. 3 are all the same as those used in FIG.

First, the outline of the overall configuration of the solenoid according to the first embodiment will be described. The present invention is suitable for a so-called long stroke solenoid having a long stroke length of, for example, 6 to 8 mm, and the solenoid 10 shown in FIGS. 1 to 3 is also a long stroke solenoid. As shown in FIG. 1, the movable magnetic pole 50 is formed in a bottomed cylindrical shape for weight reduction. The main body 51 of the movable magnetic pole 50 is arranged on the tip side inside the winding body 71 of the coil bobbin 70, and the base end side is supported by the oil-free bearing 76. The base end side of the shaft 56 is fitted to the bottom portion 52 of the movable magnetic pole 50. The tip end side of the shaft 56 is supported by an oil-free bearing 76 fixed to a fixed magnetic pole 30. Further, the convex portion 32 of the fixed magnetic pole 30 faces the tip end side of the movable magnetic pole 50, and when the coil 75 is energized, the movable magnetic pole 50 is attracted to the convex portion 32, and the state shown in FIG. 1 is obtained. The fixed magnetic pole 30 is fitted in the opening on the tip end side of the case 60, and forms a magnetic circuit together with the movable magnetic pole 50, the case 60, and the auxiliary magnetic pole 20 when the coil is energized. However, as will be described later, the present invention has a configuration in which magnetic flux hardly flows between the fixed magnetic pole 30 and the auxiliary magnetic pole 20, and a magnetic circuit having a path different from that of the fixed magnetic pole 30 and the auxiliary magnetic pole 20 is configured. It can be said that it is doing.

Further, each component of the solenoid 10 will be described. 4A and 4B show a fixed magnetic pole of a solenoid according to the first aspect of the present invention, where FIG. 4A is a front view, FIG. 4B is a plan view, and FIG. 4C is a sectional view taken along line BB. In FIG. 3, 33 is an opening, 34 and 35 are upper surfaces, 36a and 36b are pin holes, 37 and 38 are peripheral side surfaces, 39 is a lower surface, and other reference numerals are the same as those in FIG.

The fixed magnetic pole 30 is formed at the center of the main body portion 31 formed in a substantially disk shape, the convex portion 32 protruding toward the proximal end side from the region near the center of the main body portion 31, the main body portion 31, and the convex portion 32. It is provided with a circular opening 33. Since the main body portion 31 is press-fitted into the case 60, the peripheral side surface 37 is in a state of being strongly pressed against the inner peripheral surface of the case 60. Further, the main body portion 31 is formed with pin holes 36a and 36b at positions that are point-symmetrical with respect to the central axis. As shown in FIG. 2, the pin holes 36a and 36b are holes for driving the fixing pins 79a and 79b. Further, the convex portion 32 is formed in a substantially disk shape, projects toward the base end side opening side of the case 60, and is formed so as to face the movable magnetic pole 50. The peripheral side surface 38 of the convex portion 32 is a portion in contact with the spacer 40, and is used for positioning when fixing the spacer 40.

By the way, in the flat type solenoid according to the prior art, the peripheral region of the convex portion 32 has the same wall thickness as the convex portion 32, that is, the upper surface 34 of the convex portion 32 and the upper surface 35 of the peripheral region form the same plane. However, in the solenoid 10 according to this embodiment and the fictitious solenoid according to another embodiment, in order to secure a space for arranging the auxiliary magnetic pole 20 and the spacer 40, in order to secure a space for arranging the auxiliary magnetic pole 20 and the spacer 40, The wall thickness of the peripheral region of the convex portion 32 is reduced. The opening 33 is a through hole into which the oil-free bearing 77 is fitted. As described above, since the convex portion 32 is thicker than the peripheral region, the distance between the upper surface 34 and the lower surface 39 is also longer than the distance between the upper surface 35 and the lower surface 39. With this configuration, the oil-free bearing 77 can be selected to be relatively long in the central axis direction. The fact that the long oil-free bearing 77 can be adopted can prevent the movable magnetic pole 50 and the shaft 56 from sliding in a state of being slightly tilted with respect to the central axis, and can be said to be a very useful configuration for a long stroke solenoid.

5A and 5B show a spacer of a solenoid according to the first aspect of the present invention, where FIG. 5A is a front view, FIG. 5B is a plan view, and FIG. 5C is a sectional view taken along line CC. In FIG. 5, 43 is an opening, 44a is a base end side vertical surface, 44b is a tip end side tapered surface, 45 is an upper surface, 46a and 46b are pin holes, 47 and 48 are peripheral side surfaces, 49 is a lower surface, and the like. The reference numerals of are the same as those in FIG.

The spacer 40 is formed at the center of the main body portion 41 formed in a substantially disk shape, the convex portion 42 protruding from the region near the center of the main body portion 41 toward the proximal end side, the main body portion 41, and the convex portion 42. It is provided with a circular opening 43. The main body 41 is arranged so that the auxiliary magnetic pole 20 is located on the upper surface 45 side (base end side) and the fixed magnetic pole 30 is located on the lower surface 49 side (tip side), and a predetermined distance is provided between the auxiliary magnetic pole 20 and the fixed magnetic pole 30. It has a role to hold the magnetic gap of. Further, the main body 41 is formed with pin holes 46a and 46b at positions that are point-symmetrical with respect to the central axis. As shown in FIG. 2, the pin holes 46a and 46b are holes for inserting the fixing pins 79a and 79b. The spacer 40 is fixed to the fixed magnetic pole 30 by the fixing pins 79a and 79b with the auxiliary magnetic pole 20 arranged on the upper surface 45 side. Since the spacer 40 is provided with the main body 41 as a magnetic gap, a material having particularly high non-magnetic characteristics and sufficient strength, such as non-magnetic stainless steel SUS305, is desirable. If, for example, the pin holes 46a and 46b and their peripheral portions have a strength that is not deformed by a strong attractive force applied to the auxiliary magnetic pole 20, and are not easily magnetized, the material may be another material. May be good.

The convex portion 42 is formed so as to surround the opening 43 and in a shape like a substantially annular thin plate, and faces the base end portion side. Further, the peripheral side surface 48 of the convex portion 42 is used for positioning the auxiliary magnetic pole 20 as described later. The opening 43 is a through hole into which the convex portion 32 of the fixed magnetic pole 30 is inserted. The base end side vertical surface 44a of the opening 43 is a portion in contact with the peripheral side surface 38 of the convex portion 32 of the fixed magnetic pole 30, and is used for positioning when fixing the spacer 40 in the assembly process of the solenoid 10. The distal end side tapered surface 44b of the opening 43 prevents the spacer 40 from being assembled in a state of being lifted from the upper surface 35 of the fixed magnetic pole 30 due to the variation in the size of the parts, that is, the distal end side tapered surface 44b and the fixed magnetic pole. It is formed to accommodate variations in the size of parts due to the gap with 30. As described above, when the spacer 40 is fixed to the fixed magnetic pole 30 by the fixing pins 79a and 79b, the base end side vertical surface 44a is used for positioning, but the peripheral side surface 47 of the main body 41 is the case. It may be formed so as to be in contact with 60 and positioned with reference to the peripheral side surface 47. In order to return the movable magnetic pole 50 and the shaft 56 to their original positions after the energization of the coil 75 is stopped, a spring is provided in the solenoid 10, or a repulsive force is applied from a device equipped with the solenoid 10. Therefore, it is necessary to push back the movable magnetic pole 50 and the shaft 56, but since this is a matter that is not closely related to the present invention, the description thereof will be omitted.

6A and 6B show an auxiliary magnetic pole of a solenoid according to the first aspect of the present invention, where FIG. 6A is a front view and FIG. 6B is a plan view. In FIG. 6, 23 is an opening, 26a and 26b are pin holes, 27 is a peripheral side surface, 28 is an upper surface, 29 is a lower surface, and other reference numerals are the same as those in FIG. Further, FIG. 7 shows an auxiliary magnetic pole of the solenoid according to the first aspect of the present invention, (c) is a DD diagram, and (b) is a sectional view taken along line EE. In FIG. 7, 21 is a main body, 24 is a tapered surface toward the upper part, 25 is a vertical surface, and other reference numerals are the same as those in FIGS. 1 and 6.

The auxiliary magnetic pole 20 is one of the magnetic components constituting the magnetic circuit, but has a major feature in that it is not in contact with any other magnetic component. First, the auxiliary magnetic pole 20 has a main body portion 21 formed in a substantially disk shape, a convex portion 22 protruding toward the proximal end side from a region near the center of the main body portion 21, and a center of the main body portion 21 and the convex portion 22. It is provided with a circular opening 23 formed in. That is, the fixed magnetic pole 30, the spacer 40, and the auxiliary magnetic pole 20 have an approximate shape so as to be overlapped and fixed, as will be described later. The main body portion 21 serves as a path for flowing the magnetic flux flowing from the peripheral portions of the convex portion 22 and the opening portion 23 to the case 60. Further, the main body portion 21 is formed with pin holes 26a and 26b at positions that are point-symmetrical with respect to the central axis. The pin holes 26a and 26b are for inserting the fixing pins 79a and 79b from the upper surface 28 side (base end side) toward the lower surface 29 (tip end side) and driving the fixing pins 21 and the spacer 40 into the fixed magnetic pole 30. It is a hole.

The convex portion 22 is formed so as to project toward the proximal end side, shorten the magnetic gap with the movable magnetic pole 50, and facilitate the flow of magnetic flux from the movable magnetic pole 50. That is, even when the magnetic gap between the fixed magnetic pole 30 and the movable magnetic pole 50 is very large and almost no magnetic flux flows between them, the magnetic flux can flow from the movable magnetic pole 50 to the auxiliary magnetic pole 20. Therefore, it is possible to secure the thrust required in the situation shortly after the start of sliding of the movable magnetic pole 50. Further, as shown in FIGS. 1 to 3, the convex portion 22 is arranged so as to enter the inside of the winding body portion 71 of the coil bobbin 70. Further, the first flange portion 72 of the coil bobbin 70 is arranged in contact with the upper surface 28 of the main body portion 21. By arranging in this way, the space above the upper surface 28 can be effectively used without making it an empty space.

Further, the inner peripheral surface of the opening 23 is formed in a shape suitable for obtaining an intermediate characteristic between the flat type and the conical type. That is, as shown in FIG. 7 (d), the opening 23 has a tapered surface 24a on the proximal end side closer to the coil bobbin 70 whose diameter increases toward the proximal end side and is relative to the central axis of the tapered surface 24b on the distal end side. It is formed so that the inclination angle becomes small. Further, the opening 23 is formed so that the tapered surface 24b on the distal end side closer to the fixed magnetic pole 30 expands in diameter toward the distal end side and the inclination angle with respect to the central axis is larger than the tapered surface 24a on the proximal end side. There is. The configuration of the opening 23 is based on the knowledge obtained by the inventor through experiments and magnetic field analysis. First, the auxiliary magnetic pole 20 is arranged closer to the movable magnetic pole 50 than the fixed magnetic pole 30. Therefore, the inner peripheral surface of the opening 23 is different between the surface on the proximal end side and the surface on the distal end side. With this configuration, the magnetic flux flowing from the movable magnetic pole 50 to the auxiliary magnetic pole 20 does not flow to the fixed magnetic pole 30, and easily flows to the case 60. That is, two magnetic circuits are generated: a magnetic circuit that returns to the movable magnetic pole 50 via the movable magnetic pole 50, the fixed magnetic pole 30, and the case 60, and a magnetic circuit that returns to the movable magnetic pole 50 via the auxiliary magnetic pole 20 and the case 60. This is facilitated for the reasons described below.

Secondly, the surface on the distal end side is expanded toward the distal end side with respect to the central axis, and the tapered surface on the distal end side has a larger inclination angle with respect to the central axis than the tapered surface on the proximal end side 24a. By forming the surface on the tip side in this way, the durability of the solenoid 10 can be reduced by creating a magnetic gap between the auxiliary magnetic pole 20 and the main body 31 of the fixed magnetic pole 30 and the convex portion 32, particularly the peripheral side surface of the convex portion 32. If the magnetic resistance between the movable magnetic pole 50 and the fixed magnetic pole 30 is increased, the amount of magnetic flux flowing from the movable magnetic pole 50 to the fixed magnetic pole 30 via the auxiliary magnetic pole 20 is reduced as much as possible. It becomes possible. On the other hand, the effect that the amount of magnetic flux flowing from the movable magnetic pole 50 to the case 60 via the auxiliary magnetic pole 20 can be increased can be obtained.

Thirdly, the surface on the proximal end side is expanded toward the proximal end side with respect to the central axis, and the tapered surface on the proximal end side 24a has a smaller inclination angle with respect to the central axis than the tapered surface 24b on the distal end side. By forming the surface on the proximal end side in this way, the convex portion 32 of the convex portion 32 is located for a short time from the start of energization of the coil 75, that is, in a state where the movable magnetic pole 50 is located far from the fixed magnetic pole 30. The area facing the movable magnetic pole 50 on the peripheral side surface can be increased. Therefore, in a state where the movable magnetic pole 50 is located far from the fixed magnetic pole 30, it is possible to increase the amount of magnetic flux flowing from the movable magnetic pole 50 to the auxiliary magnetic pole 20 to increase the thrust of the movable magnetic pole 50.

Further, the auxiliary magnetic pole 20 is magnetically formed between the peripheral side surface 27 formed so as to be parallel to the central axis and the case 60, in addition to the characteristics of the proximal end side tapered surface 24a and the distal end side tapered surface 24b of the opening 23. There is a gap. With the configuration having a magnetic gap in this way, the magnetic resistance of the magnetic circuit from the movable magnetic pole 50 to the case 60 via the auxiliary magnetic pole 20 is reduced to the movable magnetic pole 50 in a state where the movable magnetic pole 50 is close to the fixed magnetic pole 30. It is made to be considerably larger than the magnetic resistance of the magnetic circuit from the magnetic circuit to the case 60 via the fixed magnetic pole 30. Therefore, when the movable magnetic pole 50 approaches the fixed magnetic pole 30, the amount of magnetic flux flowing from the movable magnetic pole 50 to the auxiliary magnetic pole 20 becomes very small, and the attractive force applied from the auxiliary magnetic pole 20 to the movable magnetic pole 50 also becomes small. This means that the ratio of the magnetic force components in the direction orthogonal to the central axis that does not contribute to the thrust is significantly reduced. Therefore, the auxiliary magnetic pole 20 has an effect similar to that of a conical type when the movable magnetic pole 50 is located far from the fixed magnetic pole 30, but is flat when the movable magnetic pole 50 is close to the fixed magnetic pole 30. An action effect close to that of a mold can be obtained.

8A and 8B show the components of the solenoid according to the first aspect of the present invention, where FIG. 8A is a plan view of a movable magnetic pole, FIG. 8B is a sectional view taken along line FF of the movable magnetic pole, and FIG. 8C is a shaft. A plan view, (d) is a front view of the shaft, (e) is a front view of the fixing pin, and (f) is a bottom view of the fixing pin. In FIG. 8, 53 is a tapered surface, 55 is an opening, and other reference numerals are the same as those in FIGS. 1 and 2. 9A and 9B show a case of a solenoid according to the first aspect of the present invention, where FIG. 9A is a plan view and FIG. 9B is a sectional view taken along line GG. In FIG. 9, 64 and 65 are inner peripheral surfaces, 66 is a stepped surface, and 67 is an opening.

As shown in FIGS. 8A and 8B, the movable magnetic pole 50 is formed in a substantially bottomed cylindrical shape in which the bottom portion 52 is located on the tip side, and magnetic flux flows too much in order to reduce the weight. The portion near the central axis is the hollow portion 54. Further, the tapered surface 53 is formed so that the diameter of the vicinity of the tip of the peripheral side surface of the main body 51 is reduced toward the tip side. The tapered surface 53 is formed so as to have a small inclination angle with respect to the central axis, whereby a thrust characteristic close to that of a conical type can be obtained. The opening 55 of the bottom 52 is a through hole into which the shaft 56 is fitted. As shown in FIGS. 8 (c) and 8 (d), the shaft 56 is formed in a substantially circular rod shape, and a fitting portion in which the vicinity of the end portion on the proximal end side is fitted to the opening 55 of the movable magnetic pole 50. It becomes 57. The protrusion 58 on the tip side and its vicinity slide while being supported by the oil-free bearing 77.

The case 60 is made of a magnetic material and includes a substantially cylindrical main body portion 61 having a large diameter and a substantially cylindrical small diameter portion 62 having a smaller diameter than the main body portion 61. A coil bobbin 70 or the like is housed in the main body 61. The main body 31 of the fixed magnetic pole 30 is fitted to the inner peripheral surface 64 side of the opening 67 on the distal end side of the main body 61. An oil-free bearing 76 is fitted to the inner peripheral surface 65 side of the small diameter portion 62 provided on the base end side of the main body portion 61. The step surface 66 of the step portion 63 between the main body portion 61 and the small diameter portion 62 sandwiches and holds the coil bobbin 70 together with the main body portion 21 of the auxiliary magnetic pole 20. The case 60 may have a longer substantially cylindrical shape, the base end side may be closed by a lid member, and an oil-free bearing may be fitted in the central opening of the lid member.

Further, returning to FIGS. 1 to 3, other components will be described. The coil bobbin 70 is provided with a first flange portion 72 at the distal end side end portion of the winding body portion 71, a second flange portion 73 at the proximal end side end portion, and a third flange portion near the inside of the second flange portion 73. A portion 74 is provided. A coil wire is wound between the first flange portion 72 and the third flange portion 74 to form a coil 75. A molded coil may be used instead of the normal coil. Further, as described above, the coil bobbin 70 is assembled with the convex portion 22 of the auxiliary magnetic pole 20 inserted into the opening on the tip end side of the winding body portion 71, and the coil bobbin 70 is positioned by the convex portion 22 at the time of assembly. .. Therefore, the convex portion 22 has not only a role as a member constituting the magnetic circuit but also a role as a positioning member at the time of assembling the solenoid 10. The non-lubricated bearing 76 and the non-lubricated bearing 77 support the movable magnetic pole 50 and the shaft 56, respectively. As the non-lubricated bearings 76 and 78, metal dry sch is suitable, but resin dry sch and bearings of a type that require lubrication may be used. The spacer 78 is formed in the shape of a thin disk having an opening in the center, and prevents the movable magnetic pole 50 sucked by the fixed magnetic pole 30 from sticking to the fixed magnetic pole 30 and getting stuck after the coil 75 is de-energized. do.

Subsequently, the outline of the assembly procedure of the solenoid 10 will be described. FIG. 10 is a perspective view (1) showing an assembly procedure of the solenoid according to the first embodiment of the present invention. Further, FIG. 11 is a perspective view (2) showing an assembly procedure of the solenoid according to the first embodiment of the present invention. The reference numerals used in FIGS. 10 and 11 are all the same as those used in FIG.

First, as shown in FIG. 10, the oil-free bearing 77 is press-fitted into the opening 33 of the fixed magnetic pole 30. Next, the spacer 40 is placed on the fixed magnetic pole 30 while the convex portion 32 of the fixed magnetic pole 30 is inserted into the opening 43 of the spacer 40. Further, the auxiliary magnetic pole 20 is inserted so that the peripheral side surface 48 of the convex portion 42 of the spacer 40 is in contact with the vertical surface 25 of the opening 23 of the auxiliary magnetic pole 20, that is, the convex portion 42 is inserted into the opening 23. Place it on the spacer 40. Next, after the fixing pin 79a and the fixing pin 79b are inserted into the pin holes 26a and 46a and the pin holes 26b and 46b, they are driven into the pin holes 36a and the pin holes 36b to drive the auxiliary magnetic pole 20 and the spacer. 40 is fixed to the fixed magnetic pole 30. Subsequently, as shown in FIG. 11, the oil-free bearing 76 is press-fitted into the small diameter portion 62 of the case 60, and the coil bobbin 70 and the coil 75 are further inserted into the case 60. Further, the shaft 56 is press-fitted into the opening 55 of the movable magnetic pole 50. Next, it is press-fitted into the opening 67 of the case 60. Finally, the spacer 78 is arranged on the convex portion 32 of the fixed magnetic pole 30, and the movable magnetic pole 50 and the shaft 56 are inserted into the oil-free bearing 76 and the oil-free bearing 77. According to the above steps, the spacer 40 and the auxiliary magnetic pole 20 can be accurately arranged with respect to the fixed magnetic pole 30, and the thrust characteristics assumed in the design can be obtained.

Subsequently, the characteristics of the flow of the magnetic flux during the operation of the solenoid 10 will be described. FIG. 12 is a cross-sectional view (1) showing the flow of magnetic flux in the solenoid according to the first embodiment of the present invention. In FIG. 12, 59 is a magnetic gap, and the other reference numerals are the same as those in FIG. Further, FIG. 13 is a cross-sectional view (2) showing the flow of magnetic flux in the solenoid according to the first embodiment of the present invention. The reference numerals used in FIG. 13 are all the same as those used in FIGS. 1 and 12. The curves and arrows showing the flow of magnetic flux in the figure, and their thicknesses are schematic and are not the same as the actual flow of magnetic flux. In addition, FIG. 16 is a graph showing the thrust characteristics of the solenoid according to the first and second embodiments of the present invention.

First, when the coil 75 is not energized, the movable magnetic pole 50 is located at the farthest point from the fixed magnetic pole 30 as shown in FIG. When the coil 75 is energized in this state, as shown in FIG. 12A, the magnetic gap between the movable magnetic pole 50 and the fixed magnetic pole 30 is large, so that the magnetic flux flows mainly from the movable magnetic pole 50 to the auxiliary magnetic pole 20. Flow, the flow from the movable magnetic pole 50 to the fixed magnetic pole 30 is small. Therefore, the thrust generated in the movable magnetic pole 50 is mainly due to the auxiliary magnetic pole 20. This state is maintained for a while after the start of sliding of the movable magnetic pole 50. Since the tip side tapered surface 24b is formed on the auxiliary magnetic pole 20 to greatly separate the auxiliary magnetic pole 20 from the convex portion 32 of the fixed magnetic pole 30, the amount of magnetic flux flowing from the auxiliary magnetic pole 20 to the fixed magnetic pole 30 is very small. Become a thing. Next, when the movable magnetic pole 50 approaches the fixed magnetic pole 30 slightly, as shown in FIG. 12B, the amount of magnetic flux flowing from the movable magnetic pole 50 to the fixed magnetic pole 30 is close to the amount of magnetic flux flowing from the movable magnetic pole 50 to the auxiliary magnetic pole 20. Become.

When the movable magnetic pole 50 approaches the fixed magnetic pole 30 and the magnetic gap between the movable magnetic pole 50 and the fixed magnetic pole 30 becomes smaller than the magnetic gap between the movable magnetic pole 50 and the auxiliary magnetic pole 20, as shown in FIG. 13 (c). The flow of the magnetic flux mainly flows from the movable magnetic pole 50 to the fixed magnetic pole 30, and the flow from the movable magnetic pole 50 to the auxiliary magnetic pole 20 is reduced. Therefore, the force that attracts the movable magnetic pole 50 toward the auxiliary magnetic pole 20, that is, the magnetic force that does not contribute to the thrust in the central axis direction, is considerably smaller than that of the conical solenoid according to the prior art. Further, since a magnetic gap 59 is provided between the auxiliary magnetic pole 20 and the case 60 to intentionally increase the magnetoresistance between the auxiliary magnetic pole 20 and the case 60, this configuration also has the auxiliary magnetic pole 50 to the auxiliary magnetic pole. It exerts the effect of reducing the flow to 20. Then, as shown in FIG. 13D, when the movable magnetic pole 50 abuts on the spacer 78 and the sliding of the movable magnetic pole 50 and the shaft 56 is stopped, most of the magnetic flux flows from the movable magnetic pole 50 to the fixed magnetic pole 30. become.

Further, an experiment was conducted on an example having the configuration of the above first embodiment and a comparative example of a flat type and a conical type having substantially the same configuration other than the magnetic parts. As a result, as shown in FIG. 16, the solenoid of the embodiment has characteristics similar to those of the conical type comparative example when the movable magnetic pole is located far from the fixed magnetic pole, and the movable magnetic pole approaches the fixed magnetic pole. At that time, it was found that it had characteristics similar to those of the flat type comparative example. That is, it can be said that the solenoid having the configuration of the present invention has realized a solenoid having the features of both a flat type solenoid and a conical type solenoid.

As described above, according to the solenoid 10 according to the first embodiment of the present invention, the auxiliary magnetic pole 20 is placed between the coil bobbin 70 and the fixed magnetic pole 30, that is, the movable magnetic pole 50 is far from the fixed magnetic pole 30. The auxiliary magnetic pole 20 is arranged closer to the movable magnetic pole 50 than the fixed magnetic pole 30, and there is a magnetic gap between the auxiliary magnetic pole 20 and the case 60 and the fixed magnetic pole 30. Since the magnetic gap between the auxiliary magnetic pole 20 and the case 60 is smaller than the magnetic gap between the auxiliary magnetic pole 20 and the fixed magnetic pole 30, the reluctance between the auxiliary magnetic pole 20 and the case is between the movable magnetic pole 50 and the fixed magnetic pole 30. It will be smaller than the magnetic resistance between and. Therefore, while the coil 75 is energized, the magnetic flux flowing from the movable magnetic pole 50 to the fixed magnetic pole 30 via the auxiliary magnetic pole 20 is very small. Further, since the magnetic gap between the movable magnetic pole 50 and the auxiliary magnetic pole 20 is relatively small when the coil 75 is energized, that is, when the movable magnetic pole 50 starts to slide, the magnetic flux mainly draws the auxiliary magnetic pole 20 from the movable magnetic pole 50. It flows to the case 60 via. When the movable magnetic pole 50 approaches the fixed magnetic pole 30, the magnetic gap between the movable magnetic pole 50 and the fixed magnetic pole 30 becomes smaller, and the magnetic resistance between the movable magnetic pole 50 and the fixed magnetic pole 30 becomes smaller. It flows from 50 to the case 60 via the fixed magnetic pole 30, and does not flow much to the auxiliary magnetic pole 20. That is, the auxiliary magnetic pole 20 functions for a while from the start of sliding of the movable magnetic pole 50, and when the movable magnetic pole 50 approaches the fixed magnetic pole 30, the auxiliary magnetic pole 20 does not function very much. Therefore, the first half of the operation of the movable magnetic pole 50 has the characteristics of the conical type, and the latter half of the operation of the movable magnetic pole has the characteristics of the flat type. Further, since the region near the fixed magnetic pole on the inner peripheral surface of the opening 23 formed in the center of the auxiliary magnetic pole 20 is a tapered surface 24b on the tip side that gradually expands in diameter toward the fixed magnetic pole 30, the movable magnetic pole 50 assists. The magnetic gap between the auxiliary magnetic pole 20 and the fixed magnetic pole 30 can be increased without adversely affecting the region that is the path of the magnetic flux flowing through the magnetic pole 20 to the case 60.

Further, in the opening 23 of the auxiliary magnetic pole 20, the region near the coil bobbin on the inner peripheral surface is set to the base end side tapered surface 24a whose diameter gradually increases toward the coil bobbin 70 side, so that the region near the coil bobbin on the inner peripheral surface is movable. The surface is inclined with respect to the central axis of the magnetic pole. Therefore, in the magnetic force generated by the magnetic flux flowing between the base end side tapered surface 24a and the movable magnetic pole 50, the ratio of the component parallel to the central axis of the movable magnetic pole 50 becomes larger, and the movable magnetic pole 50 starts sliding. The thrust can be further increased. In addition, since the inner peripheral side edge region of the auxiliary magnetic pole 20 on the coil bobbin 70 side is a convex portion 22 protruding toward the coil bobbin 70 side, the magnetic gap between the auxiliary magnetic pole 20 and the movable magnetic pole 50 can be shortened. , The thrust at the start of sliding of the movable magnetic pole 50 can be further increased. Further, the convex portion 22 in the inner peripheral side edge region on the coil bobbin 70 side of the auxiliary magnetic pole 20 enters the inside of the winding body portion 71 of the coil bobbin 70, and the region other than the inner peripheral side edge region on the coil bobbin 70 side is the coil bobbin 70. Since it is in contact with the first flange portion 72, the auxiliary magnetic pole 20 can be used as a holding member for the coil bobbin 70. Further, by eliminating the unnecessary space between the auxiliary magnetic pole 20 and the coil bobbin 70, it is possible to contribute to the miniaturization of the solenoid 10. In addition, a spacer 40 made of a non-magnetic material is provided between the fixed magnetic pole 30 and the auxiliary magnetic pole 20, and the auxiliary magnetic pole 20 and the spacer 40 are fixed to the fixed magnetic pole 30 by the fixing pins 79a and 79b. The magnetic gap between the fixed magnetic pole 30 and the case 60 can be set accurately. Further, since the convex portion 32 is formed around the opening 33 of the fixed magnetic pole 30, a sufficient thickness (length) for fitting the oil-free bearing 77 that supports the shaft 56 is secured in the central axis direction. be able to.

Further, a solenoid according to another embodiment of the present invention will be described. 14 is a partial cross-sectional view showing a solenoid according to the second to fourth embodiments of the present invention, FIG. 14A is a partial cross-sectional view of the solenoid according to the second embodiment, and FIG. 14B is a second embodiment. 3 is a partial cross-sectional view of the solenoid according to the third embodiment, and (c) is a partial cross-sectional view of the solenoid according to the fourth embodiment. 14; 86 is a convex part, 87a is a base end side vertical surface, 87b is a tip side tapered surface, 88 is a vertical surface, 89 is a movable magnetic pole, 90 is an auxiliary magnetic pole, 91 is a convex part, 92a is a base end side tapered surface, 92b is. The tapered surface on the tip side, 93 is a vertical surface, 94 is a spacer, and other reference numerals are the same as those in FIG. 1. 15 is a partial cross-sectional view showing the solenoid according to the fifth and sixth embodiments of the present invention, and FIG. 15D is a partial cross-sectional view of the solenoid according to the fifth embodiment, (e). Is a partial cross-sectional view of the solenoid according to the sixth embodiment. In FIG. 15, 14 and 15 are solenoids, 95 is an auxiliary magnetic pole, 96 is a convex portion, 97a is a base end side tapered surface, 97b is a tip side tapered surface, 98 is a spacer, 99 is an edge convex portion, and 100 is an auxiliary magnetic pole. 101, 102, 103, 104, 105, 106 and 107 are magnetic circular plates, 108 is a stepped surface on the distal end side, 109 is a stepped surface on the proximal end side, and other reference numerals are the same as those in FIG.

The present invention can provide a solenoid according to the following embodiment in addition to the solenoid 10 according to the first embodiment. First, as shown in FIG. 14A, in the solenoid 11 according to the second embodiment, the shapes of the proximal end side tapered surface 81a, the distal end side tapered surface 81b, and the vertical surface 82 of the auxiliary magnetic pole 80 are the auxiliary magnetic poles. The portion corresponding to the convex portion 22 of the auxiliary magnetic pole 20 is not formed, and the entire upper surface of the auxiliary magnetic pole 80 is formed so as to be at the same position as the convex portion 22 of the auxiliary magnetic pole 20 in the central axis direction. As a result, the coil bobbin 83 and the coil 84 are shorter than the coil bobbin 70 and the coil 75 in the central axis direction. Therefore, the processing of the auxiliary magnetic pole 80 is simpler than that of the auxiliary magnetic pole 20, but since the coil 84 is shorter than the coil 75, it can be said that the thrust when the coil 84 is energized is slightly weakened.

Next, in the solenoid 12 according to the third embodiment, as shown in FIG. 14B, the convex portion 86 of the auxiliary magnetic pole 85 in the central axis direction is the same as the convex portion 22 of the auxiliary magnetic pole 20. A base end-side vertical surface 87a parallel to the central axis is formed, and the movable magnetic pole 89 is not provided with a tapered surface, and the entire peripheral side surface is a surface parallel to the central axis. The tip side tapered surface 87b and the vertical surface 88 are the same as the tip side tapered surface 24b and the vertical surface 25 of the auxiliary magnetic pole 20. Therefore, the processing of the movable magnetic pole 89 is simpler than that of the movable magnetic pole 50, but since the region of the inner peripheral surface of the opening of the auxiliary magnetic pole 85 near the coil bobbin does not face the movable magnetic pole 89, the coil 75 can be processed. The thrust for a while after the start of energization is slightly weaker than that of the solenoid 10.

Subsequently, in the solenoid 13 according to the fourth embodiment, as shown in FIG. 14 (c), the spacer 94 is made thinner than the spacer 40 in the central axis direction. The shapes of the convex portion 91, the base end side tapered surface 92a, the end side tapered surface 92b, and the vertical surface 93 of the auxiliary magnetic pole 90 are the same as the corresponding portions of the auxiliary magnetic pole 20, but the auxiliary magnetic pole 90 is more oriented in the central axis direction. It is located on the tip side. However, the auxiliary magnetic pole 20 needs to be arranged closer to the movable magnetic pole 50 than the fixed magnetic pole 30. By doing so, the auxiliary magnetic pole 90 is arranged closer to the fixed magnetic pole 30 in the central axis direction, and the thrust characteristic is also closer to the solenoid on the flat side than the solenoid 10.

Further, as shown in FIG. 15D, in the solenoid 14 according to the fifth embodiment, the auxiliary magnetic pole 95 has a convex portion 96 and the shape of the tapered surface 97a on the proximal end side is the convex portion 22 of the auxiliary magnetic pole 20 and the base. It is the same as the end side tapered surface 24a, but the tip side tapered surface 97b is slightly longer in the central axis direction because it does not form a vertical surface. Further, the spacer 98 is provided with an edge convex portion 99 in the vicinity of the edge portion on the outer peripheral side. The edge convex portion 99 is used for positioning the auxiliary magnetic pole 95 when assembling the solenoid 14. Therefore, it can be said that the configuration is opposite to that of other embodiments in which the vicinity of the edge portion on the inner peripheral side is used for positioning the auxiliary magnetic pole.

Subsequently, the auxiliary magnetic pole 100 of the solenoid 15 according to the sixth embodiment is a magnetic circular plate 101, 102, 103, 104, 105, 106 in which the auxiliary magnetic pole 95 of the solenoid 14 is laminated as shown in FIG. 15 (e). It is configured to be composed of 107. Further, by setting the diameters of the openings of the magnetic circular plates 101, 102, 103, 104, 105, 106 and 107 to different predetermined diameters, a group corresponding to the proximal end side tapered surface 97a and the distal end side tapered surface 97b. It constitutes an end-side stepped surface 108 and a tip-side stepped surface 109. Therefore, there is an advantage that an auxiliary magnetic pole having a complicated shape in the central axis direction can be formed by laminating magnetic circular plates 101, 102, 103, 104, 105, 106 and 107 having a relatively simple outer shape.

According to the findings obtained by the inventor from experiments and magnetic field analysis, even in the solenoid according to each of the above embodiments, the auxiliary magnetic pole becomes a movable magnetic pole rather than the fixed magnetic pole when the energization to the coil is stopped. On the other hand, they are arranged so as to be close to each other (closest parts are close to each other), a magnetic gap must be provided between the auxiliary magnetic pole and the surrounding magnetic member, and the tapered surface on the distal end side is closer to the tapered surface on the proximal end side than the tapered surface 24 on the proximal end side. It is especially important to make a large tilt with respect to the central axis to provide a sufficient magnetic gap between the auxiliary and fixed magnetic poles.

The present invention is not limited to the contents described above. For example, in the solenoid 10 according to the first embodiment of the present invention, the configuration of the solenoid according to the second to sixth embodiments of the present invention. It is possible to make various configurations as long as it does not deviate from the scope described in each claim, such as incorporating a part of the above.

10 Solenoid 11 Solenoid 12 Solenoid 13 Solenoid 14 Solenoid 15 Auxiliary magnetic pole 21 Main body 22 Convex part 23 Opening 24a Base end side tapered surface 24b Tip side tapered surface 25 Vertical surface 26a Pin hole 26b Pin hole 27 Peripheral side surface 28 Top surface 29 Bottom surface 30 Fixed magnetic pole 31 Main body 32 Convex 33 Opening 34 Top surface 35 Top surface 36a Pin hole 36b Pin hole 37 Peripheral side 38 Peripheral side 39 Bottom surface 40 Spacer 41 Main body 42 Convex 43 Opening 44a Base end side Vertical surface 44b Tip side tapered surface 45 Top surface 46a Pin hole 46b Pin hole 47 Peripheral side surface 48 Peripheral side surface 49 Bottom surface 50 Movable magnetic pole 51 Main body 52 Bottom 53 Tapered surface 54 Hollow part 55 Opening 56 Shaft 57 Fitting part 58 Projection Part 59 Magnetic gap 60 Case 61 Main body part 62 Small diameter part 63 Step part 64 Inner peripheral surface 65 Inner peripheral surface 66 Step surface 67 Opening part 70 Coil bobbin 71 Winding body 72 First flange part 73 Second flange part 74 Third flange part 75 Coil 76 Oil-free bearing 77 Oil-free bearing 78 Spacer 79a Fixing pin 79b Fixing pin 80 Auxiliary magnetic pole 81a Base end side tapered surface 81b Tip side tapered surface 82 Vertical surface 83 Coil bobbin 84 Coil 85 Auxiliary magnetic pole 86 Convex part 87a Base end side vertical Surface 87b Tip side tapered surface 88 Vertical surface 89 Movable magnetic pole 90 Auxiliary magnetic pole 91 Convex part 92a Base end side tapered surface 92b Tip side tapered surface 93 Vertical surface 94 Spacer 95 Auxiliary magnetic pole 96 Convex part 97a Base end side tapered surface 97b Tip side taper Surface 98 Spacer 99 Edge convex part 100 Auxiliary magnetic pole 101 Magnetic circular plate 102 Magnetic circular plate 103 Magnetic circular plate 104 Magnetic circular plate 105 Magnetic circular plate 106 Magnetic circular plate 107 Magnetic circular plate 108 Base end side stepped surface 109 Tip side stepped surface Surface 200 Solenoid 201 Fixed magnetic pole 202 Opposing part 203 Movable magnetic pole 204 Opposing part 205 Case 206 Coil 210 Solenoid 211 Fixed magnetic pole 212 Opposing part 213 Movable magnetic pole 214 Opposing part 215 Case 216 Coil

Claims (7)

A case made of magnetic material and formed into a substantially cylindrical shape with openings at both ends,
A coil bobbin provided inside the case and having a winding body portion having a hollow portion extending along the central axis and flanges provided at both ends of the winding body portion, and a coil bobbin.
A coil formed by winding a coil wire around the coil bobbin,
From a main body formed in a substantially annular plate shape and provided to close one of the openings of the case, an opening formed in the center of the main body, and a peripheral region of the opening. A fixed magnetic pole with a convex portion protruding toward the opening side of the other side of the case, and a fixed magnetic pole.
It is formed in a substantially cylindrical shape, a substantially bottomed cylinder shape, or a substantially cylindrical shape, is arranged so as to be inserted through the winding body portion of the coil bobbin, and is attracted to the fixed magnetic pole to move when the coil is energized. With the movable magnetic pole provided in
It is formed in a substantially annular plate shape, and a magnetic gap is formed between the coil bobbin and the fixed magnetic pole between the case and the fixed magnetic pole, and the case is between the case and the case. A solenoid characterized by having an auxiliary magnetic pole arranged such that the magnetic gap is smaller than the magnetic gap between the fixed magnetic poles. The auxiliary magnetic pole is a tapered surface or a staircase in which the entire area of the inner peripheral surface of the opening formed in the center near the fixed magnetic pole, or a portion other than the vicinity of the lower end portion, gradually expands in diameter toward the fixed magnetic pole side. The solenoid according to claim 1, wherein the solenoid is formed on a surface. It said auxiliary magnetic pole to claim 2, wherein said coil bobbin side of the region of the inner peripheral surface of the opening portion is formed in a tapered surface or a stepped surface gradually diverging toward the coil bobbin side The solenoid described. The solenoid according to any one of claims 1 to 3, wherein the auxiliary magnetic pole is formed so that the inner peripheral side edge region on the coil bobbin side projects toward the coil bobbin side. .. In the auxiliary magnetic pole, the inner peripheral side edge region on the coil bobbin side enters the inside of the winding body portion of the coil bobbin, and the region other than the inner peripheral side edge region on the coil bobbin side is on one of the flanges of the coil bobbin. The solenoid according to claim 4, wherein the solenoid is provided so as to be in contact with each other. Further, a spacer made of a non-magnetic material and arranged between the auxiliary magnetic pole and the fixed magnetic pole, and
One of claims 1 to 5, wherein the auxiliary magnetic pole, the spacer, and the fixed magnetic pole are penetrated, and the auxiliary magnetic pole and the spacer are fixed to the fixed magnetic pole. Solenoids described in the section. Further, a shaft fixed to the movable magnetic pole and provided so as to extend along the central axis of the movable magnetic pole,
The solenoid according to any one of claims 1 to 6, wherein the solenoid is fitted in the opening of the fixed magnetic pole and has a bearing that supports the sliding of the shaft.

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