Solenoid device

Abstract

Provided is a solenoid device which is easy to control.　A solenoid device 10 attracts and moves a movable iron core 70 to a fixed iron core 50 by energizing a coil 21. One of the movable iron core 70 and the fixed iron core 50 has an annular recess 71, and the other of the movable iron core 70 and the fixed iron core 50 has an annular projection 52 that can be nested with the annular recess 71, and a second annular projection 53 that is arranged parallel to the annular projection 52 at a different height from the annular projection 52.

Description

Solenoid Device

[0001] The present invention relates to a solenoid device, for example, a solenoid device that operates various devices using a movable iron core.

[0002] Solenoid devices are used in a variety of industrial fields as a means for operating various devices such as valves and machines. A solenoid device operates various devices by electromagnetically moving a movable iron core that is arranged so as to be able to reciprocate when current is passed through a coil.

[0003] The solenoid device disclosed in Patent Document 1 includes a coil, a moving core, and a stator. The moving core has a ring groove formed on its end face facing the stator. The ring groove is defined by an annular wall portion on the outer diameter side, an annular wall portion on the inner diameter side, and a bottom wall portion. The stator has a cylindrical protrusion formed on its end face facing the moving core. This cylindrical protrusion can be inserted into the ring groove in the moving core. In other words, the walls of the moving core and the cylindrical protrusion in the stator can be nested together by bringing the moving core and the stator into close proximity.

[0004] In the solenoid device of Patent Document 1, when current is applied to the coil, magnetic flux is transmitted between the outer annular wall portion of the moving core and the outer diameter side of the cylindrical protrusion of the stator, and magnetic flux is transmitted between the inner diameter side annular wall portion of the moving core and the inner diameter side of the cylindrical protrusion of the stator. In other words, the outer diameter side annular wall portion and the inner diameter side annular wall portion of the moving core are each attracted to the cylindrical protrusion of the stator, thereby increasing the force with which the stator attracts the moving core.

[0005] Japanese Patent Application Laid-Open No. 2004-301165 (page 9, Figure 2)

[0006] In a solenoid device such as that described in Patent Document 1, the annular wall portion on the outer diameter side and the annular wall portion on the inner diameter side of the moving core have a tapered shape that narrows toward the stator side, so that the magnetic flux transmitted in accordance with the stroke at the beginning of the movement of the moving core gradually increases, preventing the moving core from suddenly approaching the stator.

[0007] The cross section of the ring groove in the moving core is generally rectangular, and the cross section of the cylindrical protrusion in the stator is also generally rectangular. As a result, the magnetic flux transmitted between the moving core and the stator becomes larger in the radial direction as the moving core and the stator approach each other and the area where each annular wall and the cylindrical protrusion overlap in the radial direction becomes wider, and therefore the attractive force that attracts the moving core in the axial direction decreases.

[0008] Furthermore, the heights of the outer diameter side annular wall portion and the inner diameter side annular wall portion of the moving core are approximately the same. As a result, the attractive force generated between the outer diameter side annular wall portion and the cylindrical protrusion of the stator and the attractive force generated between the inner diameter side annular wall portion and the cylindrical protrusion change at approximately the same time in accordance with the stroke of the moving core. Because the thrust acting on the moving core changes significantly in accordance with the stroke of the moving core, there was a problem in that control became complicated.

[0009] The present invention has been made in view of these problems, and has as its object to provide a solenoid device that is easy to control.

[0010] To solve the above problem, the solenoid device of the present invention is a solenoid device (10) that attracts and moves a movable iron core (70) toward a fixed iron core (50) by passing current through a coil (21), wherein one of the movable iron core (70) and the fixed iron core (50) has an annular recess (71), and the other of the movable iron core (70) and the fixed iron core (50) has an annular protrusion (52) that can be nested within the annular recess (71) and a second annular protrusion (53) that is juxtaposed to the annular protrusion (52) and has a different height. This allows the attractive force generated between the mating iron core (70) and the annular protrusion (52) and the attractive force generated between the mating iron core (70) and the second annular protrusion (53) to be generated and changed in stages. This allows the thrust acting on the movable iron core (70) toward the fixed iron core (50) to transition smoothly with respect to the stroke, simplifying control.

[0011] At least one of the annular protrusion (52) and the second annular protrusion (53) may overlap the mating iron core (70) in the radial direction at the maximum stroke, thereby generating a high thrust from the beginning of the stroke.

[0012] The tip of the annular protrusion (52) may be tapered, thereby enabling the suction force generated between the annular protrusion (52) and one of the inner and outer annular wall portions (73) forming the annular recess (71) and the suction force generated between the annular protrusion (52) and the other annular wall portion (72) to be generated and changed in a stepwise manner.

[0013] The tip of the annular protrusion (52) may have a tapered shape that narrows in the radial direction on the side away from the second annular protrusion (53). This allows the suction force generated between the annular protrusion (52) and one of the inner and outer annular wall portions (73) forming the annular recess (71) and the suction force generated between the second annular protrusion (53) and one of the annular wall portions (73) to be generated and changed in a stepwise manner.

[0014] The annular convex portion (52) may be higher than the second annular convex portion (53). This allows the suction force generated between the annular convex portion (52) and one of the inner and outer annular wall portions (73) forming the annular recess (71), the suction force generated between the annular convex portion (52) and the other annular wall portion (72), and the suction force generated between the second annular convex portion (53) and one of the annular wall portions (73) to be generated and changed in a stepwise manner.

[0015] The second annular protrusion (53) may face only one of the inner and outer annular wall portions (73) forming the annular recess (71) and may be axially separated from the one annular wall portion (73) at the maximum stroke. This allows for an attractive force to be generated between the second annular protrusion (53) and one of the inner and outer annular wall portions (73) forming the annular recess (71) at the beginning of the stroke, while making it difficult for a lateral force to be generated. Furthermore, it is possible to make it difficult for an excessive thrust to be generated by a lateral force generated between the other annular wall portion (72) and the annular protrusion (52).

[0016] The tip of the second annular protrusion (53) may be tapered in the radial direction toward the mating iron core (70), thereby reducing the generation of lateral force.

[0017] FIG. 1 is a cross-sectional view of a solenoid valve to which a solenoid device of Example 1 according to the present invention is applied. FIG. 2 is a cross-sectional view showing an enlarged view of a main portion of the solenoid device of Example 1 at maximum stroke. FIG. 3 is a view showing a state in which the movable iron core has moved toward the second fixed iron core from FIG. 2. FIG. 4 is a view showing a state in which the movable iron core has moved toward the second fixed iron core from FIG. 3. FIG. 5 is a cross-sectional view showing an enlarged view of a main portion of the solenoid device of Example 1 at minimum stroke. FIG. 6 is a graph showing actual measurement results for the solenoid device of Example 1. FIG. 7 is a cross-sectional view of a solenoid valve to which a solenoid device of Example 2 according to the present invention is applied. FIG. 8 is a cross-sectional view showing an enlarged view of a main portion of the solenoid device of Example 2 at maximum stroke. FIG. 9 is a cross-sectional view showing an enlarged view of a main portion of the solenoid device of Example 2 at minimum stroke. FIG. 10 is a graph showing actual measurement results for the solenoid device of Example 2.

[0018] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A solenoid device according to the present invention will be described below with reference to an embodiment.

[0019] In this specification, of the forces acting on the movable iron core 70 by the magnetic flux, the force that attracts the movable iron core 70 axially toward the second fixed iron core 50 is called the attraction force, and the force that attracts the movable iron core 70 radially toward the second fixed iron core 50 is called the lateral force.

[0020] Furthermore, the force acting on the movable core 70 toward the second fixed core 50 is defined as positive, and the attractive force acting on the movable core 70 during one stroke (F Ｂ ) and the biasing force of the spring 5 (-F Ｓｐ ) is called thrust (N) (N = F Ｂ + (-F Ｓｐ )).

[0021] A solenoid device according to a first embodiment will be described with reference to Figures 1 to 6. In the following description, the left and right sides of Figure 1 will be taken as the left and right sides of the solenoid device.

[0022] 1, the solenoid device 10 is applied to a spool-type solenoid valve 1. The solenoid valve 1 is used in hydraulically controlled devices such as an automatic transmission of a vehicle. However, the solenoid device 10 may also be applied to devices other than the solenoid valve 1.

[0023] The solenoid valve 1 comprises a cylindrical sleeve 2, a spool 3 inserted into the sleeve 2, a retainer 4 fixed to the right axial end of the sleeve 2, a spring 5 arranged in a compressed state between the spool 3 and the retainer 4, and a solenoid device 10.

[0024] A plurality of ports (not shown) through which the working fluid can flow are formed in the sleeve 2. The spool 3 is capable of reciprocating in the axial direction.

[0025] The solenoid valve 1 can control the pressure and flow rate of hydraulic oil by switching the communication state of various ports according to the position of the spool 3. The sleeve 2, spool 3, and retainer 4 are made of materials such as aluminum, iron, stainless steel, and resin.

[0026] The solenoid device 10 includes a solenoid case 11, a plate 12, a solenoid molding 20, a first fixed core 30, a spacer 40, a second fixed core 50, an annular plate 60, a movable core 70, and a rod 80.

[0027] The solenoid case 11 is formed of a magnetic material such as iron and has a cylindrical shape with a bottom. The solenoid case 11 accommodates a coil 21, a first stationary core 30, a spacer 40, a second stationary core 50, an annular plate 60, a movable core 70, and a rod 80.

[0028] A plate 12 is fixed by crimping to the left end of the solenoid case 11. The plate 12 is made of a magnetic material and has a disk shape. However, the plate 12 may be made of a non-magnetic material. The left end of the sleeve 2 is fixed by crimping to the right end of the solenoid case 11.

[0029] The plate 12 and the sleeve 2 hold the first stationary core 30, the spacer 40, the second stationary core 50, and the annular plate 60 by sandwiching them in the axial direction.

[0030] The solenoid body 20 is formed by molding a coil 21 and a connector 22 electrically connected to the coil 21 with resin.

[0031] The cylindrical portion 31 of the first stationary core 30, the spacer 40, and the second stationary core 50 are inserted inside the coil 21 in the solenoid molded body 20. The coil 21 is also disposed axially between the flange portion 32 of the first stationary core 30 and the annular plate 60. The coil 21 generates magnetic flux when power is supplied from a power source (not shown) through a connector 22.

[0032] The first stator core 30 is made of a magnetic material and is formed in a cylindrical shape with a flange, having a tubular portion 31 and a flange 32 portion.

[0033] The spacer 40 is formed into a cylindrical shape from a non-magnetic material such as an aluminum alloy or resin.

[0034] The cylindrical portion 31 of the first stationary core 30 is fitted and fixed to the left side of the spacer 40 in the axial direction. Furthermore, the second annular protrusion 53 of the second stationary core 50 is fitted and fixed to the right side of the spacer 40 in the axial direction.

[0035] The second stator core 50 is made of a magnetic material and has a cylindrical shape. The second stator core 50 will be described in detail later.

[0036] The annular plate 60 is made of a magnetic material and has an annular disk shape. The annular plate 60 is molded together with the coil 21 and the like, and is integrated with the solenoid body 20.

[0037] The movable core 70 is made of a magnetic material and has a cylindrical shape. The movable core 70 is inserted axially movably into a through-hole that passes through the first fixed core 30 in the axial direction. The movable core 70 will be described in detail later.

[0038] The rod 80 is made of a non-magnetic material and has a cylindrical shape. The rod 80 is inserted into a through-hole that passes through the second fixed core 50 in the axial direction so as to be movable in the axial direction. The rod 80 receives the biasing force of the spring 5 via the spool 3 and is pressed against the first annular wall portion 72 of the movable core 70 in the axial direction.

[0039] Next, the second fixed core 50 and the movable core 70 will be described with reference to Fig. 2. The second fixed core 50 has a base 51, a first annular convex portion 52 on the inner diameter side as an annular convex portion, and a second annular convex portion 53 on the outer diameter side as a second annular convex portion.

[0040] The base 51 has a cylindrical shape extending in the axial direction, and its outer diameter is approximately the same as the maximum outer diameter of the tubular portion 31 in the first stator core 30. The base 51 also has an inner diameter smaller than the inner diameter of the tubular portion 31.

[0041] The first annular protrusion 52 is formed in a cylindrical shape that protrudes axially leftward from the left end face of the base 51. The first annular protrusion 52, together with the base 51, defines a through hole of the second stator core 50.

[0042] The first annular protrusion 52 extends axially leftward from the left end face of the base 51 with substantially the same thickness, i.e., substantially the same radial dimension, and then tapers from the outer diameter side toward the inner diameter side, extending axially leftward. The first annular protrusion 52 has an inner diameter side surface 52a, a first top surface 52b, a second top surface 52c that is an inclined surface, and an outer diameter side surface 52d.

[0043] The inner diameter side surface 52a is part of the inner circumferential surface of the second fixed core 50 and extends linearly in the axial direction.

[0044] The first top surface 52b extends linearly toward the outer diameter side, substantially perpendicular to the left axial end of the inner diameter side surface 52a.

[0045] The second top surface 52c extends linearly from the outer diameter end of the first top surface 52b to the outer diameter side, inclining to the right in the axial direction.

[0046] The outer diameter side surface 52d extends linearly from the outer diameter end of the second top surface 52c to the right in the axial direction and is substantially parallel to the inner diameter side surface 52a.

[0047] The second annular protrusion 53 is formed on the outer diameter side of the first annular protrusion 52 , and its outer diameter is smaller than the outer diameter of the base portion 51 .

[0048] The second annular protrusion 53 extends axially leftward with approximately the same thickness from the left end face of the base 51, and then tapers from the outer diameter side toward the inner diameter side, extending axially leftward. The second annular protrusion 53 has an inner diameter side surface 53a, a top surface 53b, an outer diameter side top surface that forms a slope, and an outer diameter side surface.

[0049] The inner diameter side surface 53a extends linearly in the axial direction.

[0050] The top surface 53b extends linearly toward the outer diameter side, generally perpendicular to the left axial end of the inner diameter side surface 53a. The top surface 53b is formed axially to the right of the first top surface 52b of the first annular protrusion 52. In other words, the tip of the first annular protrusion 52, i.e., the left axial end, protrudes axially to the left of the tip of the second annular protrusion 53. In other words, the first annular protrusion 52 and the second annular protrusion 53 have different axial lengths, i.e., heights.

[0051] The first annular protrusion 52 and the second annular protrusion 53 define an annular groove 54. More specifically, the annular groove 54 is defined by a second top surface 52c and a side surface 52d on the outer diameter side of the first annular protrusion 52, and a side surface 53a and a bottom surface 54a on the inner diameter side of the second annular protrusion 53, and is open toward the left in the axial direction.

[0052] The bottom surface 54a extends radially and is substantially perpendicular to the axis of the second fixed core 50. The bottom surface 54a is continuous with the axial right end of the outer diameter side surface 52d of the first annular protrusion 52 and the axial right end of the inner diameter side surface 53a of the second annular protrusion 53.

[0053] A non-magnetic annular stopper 55 is disposed in the recessed portion 56 of the annular groove 54. The recessed portion 56 is defined by a bottom surface 54a, a side surface 52d, and a side surface 53a.

[0054] The movable core 70 is formed in a cylindrical shape with a through hole passing through its radial center in the axial direction. The movable core 70 extends in the axial direction with its outer diameter being approximately the same. The outer diameter of the movable core 70 is slightly smaller than the inner diameter of the first stator core 30 and the inner diameter of the second annular protrusion 53 of the second stator core 50.

[0055] The movable core 70 has, at its right end, a first annular wall portion 72 on the inner diameter side as the other annular wall portion, and a second annular wall portion 73 on the outer diameter side as one annular wall portion, with an annular recess 71 formed radially between them. The annular recess 71 is recessed from the radial center of the right end face of the movable core 70 to the left in the axial direction and is open toward the right in the axial direction. In other words, the annular recess 71 is defined by the first annular wall portion 72 on the inner diameter side and the second annular wall portion 73 on the outer diameter side.

[0056] The first annular wall portion 72 has a substantially uniform thickness and extends axially to the right. The first annular wall portion 72 has an inner diameter side surface 72a, a top surface 72b, and an outer diameter side surface 72c.

[0057] The inner diameter side surface 72a is a part of the inner peripheral surface of the movable core 70 and extends linearly in the axial direction.

[0058] The top surface 72b is located on the right end surface of the movable core 70 closer to the inner diameter side than the annular recess 71, and extends linearly toward the outer diameter side, generally perpendicular to the right axial end of the inner diameter side surface 72a.

[0059] The outer diameter side surface 72c extends linearly to the left in the axial direction, generally perpendicular to the outer diameter end of the top surface 72b. The side surface 72c extends generally parallel to the inner diameter side surface 52a of the first annular protrusion 52 of the second fixed core 50, and can be disposed opposite to and slightly spaced apart in the radial direction (see FIG. 5).

[0060] The second annular wall portion 73 has a tapered shape that tapers from the inner diameter side to the outer diameter side, extends axially to the right, and then extends axially to the right with approximately the same thickness. The second annular wall portion 73 has a second bottom surface 71 b, an inner diameter side surface 73 a, a top surface 73 b, and an outer diameter side surface 73 c, which will be described later.

[0061] The inner diameter side surface 73a extends linearly in the axial direction and is generally parallel to the outer diameter side surface 52d of the first annular protrusion 52, and can be disposed opposite to and slightly spaced apart in the radial direction (see FIG. 5).

[0062] The top surface 73b is located on the right end face of the movable core 70 closer to the outer diameter than the annular recess 71, and extends linearly toward the outer diameter, generally perpendicular to the right axial end of the inner diameter side surface 73a. The top surface 73b is disposed substantially parallel to and opposite the bottom surface 54a of the second fixed core 50.

[0063] The top surface 73b and the top surface 72b of the first annular wall portion 72 are disposed on approximately the same plane.

[0064] The outer diameter side surface 73c is a part of the outer peripheral surface of the movable core 70 and extends linearly in the axial direction. The outer diameter side surface 73c extends linearly to the left in the axial direction, generally perpendicular to the outer diameter end of the top surface 73b. The side surface 73c extends generally parallel to the inner diameter side surface 53a of the second annular protrusion 53, and can be disposed opposite to and slightly spaced apart in the radial direction (see FIG. 5).

[0065] The second annular wall portion 73 is formed so as to be insertable into the annular groove portion 54 of the second stationary core 50. That is, the second annular wall portion 73 and the annular groove portion 54 can be arranged in a nested state (see FIG. 5).

[0066] The annular recess 71 is defined by an outer diameter side surface 72 c of the first annular wall portion 72 , a first bottom surface 71 a , a second bottom surface 71 b which is an inclined surface, and an inner diameter side surface 73 a of the second annular wall portion 73 .

[0067] The first bottom surface 71 a extends linearly toward the outer diameter side, generally perpendicular to the left axial end of the outer diameter side surface 72 c of the first annular wall portion 72. The first bottom surface 71 a is disposed substantially parallel to and opposite to the first top surface 52 b of the first annular protrusion 52.

[0068] The second bottom surface 71b extends linearly from the outer diameter end of the first bottom surface 71a to the right in the axial direction and is continuous with the left axial end of the inner diameter side surface 73a of the second annular wall portion 73. The second bottom surface 71b is disposed substantially parallel to and opposite to the second top surface 52c of the first annular protrusion 52.

[0069] Furthermore, the first annular protrusion 52 of the second stationary core 50 can be inserted into the annular recess 71. That is, the annular recess 71 and the first annular protrusion 52 can be arranged in a nested state (see FIG. 5).

[0070] In the second fixed core 50 and the movable core 70, the first annular convex portion 52 and the first annular wall portion 72, and the second annular convex portion 53 and the second annular wall portion 73, respectively, function as so-called cylindrical suction portions from the beginning of the stroke (see Figure 2).

[0071] The portion of the first annular protrusion 52 rearward from the corner 52e, i.e., the outer diameter side surface 52d and the second annular wall 73, function as a cylindrical suction portion from the middle of the stroke (see FIG. 3). The corner 52e is continuous with the second top surface 52c and the outer diameter side surface 52d.

[0072] In addition, the first top surface 52b of the first annular convex portion 52 and the first bottom surface 71a of the movable core 70, and the second top surface 52c of the first annular convex portion 52 and the second bottom surface 71b of the movable core 70 each function as a so-called opposing magnetic pole type attraction portion at the end of the stroke (see Figures 4 and 5).

[0073] The bottom surface 54a of the second fixed core 50 and the top surface 73b of the second annular wall portion 73 are separated by a long distance even at the end of the stroke, and do not function as an opposing magnetic pole type attracting portion.

[0074] Next, the operation of the solenoid device 10 will be described. Note that overlapping descriptions will be simplified or omitted. Also, in Figures 2 to 5, black arrows schematically show the magnetic flux transmitted between the second fixed core 50 and the movable core 70. Furthermore, in this embodiment, for the sake of convenience, the magnetic flux will be described as flowing from the second fixed core 50 toward the movable core 70.

[0075] 1 and 2, the state when the coil 21 is not energized will be described. In this state, the movable core 70 is stationary at a position farthest axially from the second fixed core 50 due to the biasing force of the spring 5 received through the rod 80 and the spool 3. In the present invention, the axial distance at which the movable core 70 is farthest from the second fixed core 50 is defined as the maximum stroke.

[0076] 2 , the first annular protrusion 52 of the second stator core 50 is nested within the annular recess 71 of the movable core 70. That is, the tip of the first annular protrusion 52 and the tip of the first annular wall 72 overlap in the radial direction. Furthermore, the second annular protrusion 53 of the second stator core 50 is spaced apart from the second annular wall 73 of the movable core 70 in the axial direction.

[0077] 1 , when current begins to be applied to the coil 21, magnetic flux flows through the magnetic path of the solenoid device 10. The magnetic path is mainly composed of the solenoid case 11, the annular plate 60, the second stator core 50, the movable core 70, and the first stator core 30.

[0078] As a result, an attractive force is generated between the first annular protrusion 52 and the first annular wall 72, and between the second annular protrusion 53 and the second annular wall 73. The sum of these attractive forces exceeds the biasing force of the spring 5, causing the movable core 70 to move toward the second fixed core 50.

[0079] More specifically, immediately after the start of energization, the second annular protrusion 53 and the second annular wall 73 are spaced apart in the axial direction, and the axial component of magnetic flux is more likely to be larger than the radial component, i.e., the component toward the inner diameter side in Figure 2. As a result, almost no lateral force is generated.

[0080] Furthermore, since the first annular protrusion 52 and the first annular wall 72 overlap in the radial direction, a high thrust can be generated from the beginning of the stroke.

[0081] [Mid-Stage Stroke] Referring to FIG. 3, when the movable core 70 moves toward the second fixed core 50, the area where the first annular protrusion 52 and the first annular wall 72 overlap in the radial direction expands.

[0082] As a result, the amount of magnetic flux transmitted from the first annular protrusion 52 to the first annular wall 72 increases with stroke. The rate of increase of the component toward the inner diameter side is relatively greater than the rate of increase of the component toward the axial direction. This results in a relatively greater ratio of the lateral force to the attractive force generated between the first annular protrusion 52 and the first annular wall 72 (hereinafter simply referred to as "the lateral force increases").

[0083] Furthermore, the annular groove 54 and the second annular wall 73 are nested within each other. That is, the second annular protrusion 54 and the second annular wall 73 overlap in the radial direction, increasing the lateral force generated therebetween.

[0084] In addition, in the state shown in Figure 3, the corner 52e of the first annular protrusion 52 and the second annular wall portion 73 are close to each other, and magnetic flux is transmitted between the first annular protrusion 52 and the second annular wall portion 73, generating an attractive force.

[0085] Because magnetic flux is transmitted from the first annular protrusion 52 to both the first annular wall 72 and the second annular wall 73, the amount of magnetic flux induced from the base 51 to the first annular protrusion 52 is greater than the amount of magnetic flux induced from the base 51 to the second annular protrusion 53. This reduces the lateral force generated between the second annular protrusion 53 and the second annular wall 73.

[0086] 2 , the rate of increase of the magnetic flux induced from the base 51 to the first annular protrusion 52 and transmitted to the second annular wall 73 is relatively greater than the rate of increase of the magnetic flux transmitted to the first annular wall 72. This makes it possible to reduce the lateral force generated between the first annular protrusion 52 and the first annular wall 72.

[0087] The magnetic flux transmitted between the first annular protrusion 52 and the second annular wall 73 has a component directed toward the outer diameter side. The lateral force generated between them attracts the second annular wall 73 toward the inner diameter side. The magnetic flux transmitted between the second annular protrusion 53 and the second annular wall 73 has a component directed toward the inner diameter side. The lateral force generated between them attracts the second annular wall 73 toward the outer diameter side.

[0088] In other words, the lateral force generated between the first annular protrusion 52 and the second annular wall 73 and the lateral force generated between the second annular protrusion 53 and the second annular wall 73 are directed in opposite directions, so the overall lateral force can be reduced, and hysteresis is also reduced.

[0089] Furthermore, the magnetic flux transmitted between the first annular protrusion 52 and the first annular wall 72 has a component directed toward the inner diameter side. In other words, the lateral force generated between the first annular protrusion 52 and the first annular wall 72 and the lateral force generated between the first annular protrusion 52 and the second annular wall 73 are directed in opposite directions, thereby reducing the overall lateral force. Hysteresis is also reduced.

[0090] [Regarding the end of stroke 1] Referring to Figure 4, when the movable core 70 moves further toward the second fixed core 50, the second top surface 52c of the second fixed core 50 and the second bottom surface 71b of the movable core 70 come close to each other, and magnetic flux is transmitted from the second top surface 52c to the second bottom surface 71b, generating an attractive force.

[0091] As a result, the amount of magnetic flux induced from the base 51 to the first annular convex portion 52 is even greater than the amount of magnetic flux induced from the base 51 to the second annular convex portion 53, thereby reducing the lateral force generated between the second annular convex portion 53 and the second annular wall portion 73.

[0092] 3 , the rate of increase of the magnetic flux induced from the base 51 to the first annular protrusion 52 and transmitted to the second annular wall 73 is relatively greater than the rate of increase of the magnetic flux transmitted to the first annular wall 72. This reduces the lateral force generated between the first annular protrusion 52 and the first annular wall 72.

[0093] The second top surface 52c and the second bottom surface 71b are inclined. Therefore, the transmitted magnetic flux has a component directed to the left in the axial direction and a component directed to the outer diameter side, which are approximately equal. The lateral force generated between these components attracts the second annular wall portion 73 toward the inner diameter side.

[0094] In other words, the lateral force generated between the first annular protrusion 52 and the second annular wall 73 and the lateral force generated between the second annular protrusion 53 and the second annular wall 73 are directed in opposite directions, so the overall lateral force can be reduced. Hysteresis is also reduced. The same applies to the lateral force generated between the first annular protrusion 52 and the first annular wall 73 and the lateral force generated between the first annular protrusion 52 and the second annular wall 73.

[0095] Furthermore, the second top surface 52c and the second bottom surface 71b are substantially parallel to each other. Therefore, the components of the transmitted magnetic flux are less likely to change depending on the stroke. As a result, the second top surface 52c and the second bottom surface 71b continue to contribute to increasing the attractive force and reducing the relative lateral force while the magnetic flux is being transmitted.

[0096] 5, when the movable core 70 moves further toward the second fixed core 50, the first top surface 52b of the first annular convex portion 52 and the first bottom surface 71a of the movable core 70 approach each other, and magnetic flux is transmitted from the first top surface 52b to the first bottom surface 71a. Also, the amount of magnetic flux transmitted from the second top surface 52c to the second bottom surface 71b increases.

[0097] As a result, the amount of magnetic flux induced from the base 51 to the first annular convex portion 52 is even greater than the amount of magnetic flux induced from the base 51 to the second annular convex portion 53, thereby reducing the lateral force generated between the second annular convex portion 53 and the second annular wall portion 73.

[0098] 4 , the rate of increase of the magnetic flux induced from the base 51 to the first annular protrusion 52 and transmitted to the second annular wall 73 is relatively greater than the rate of increase of the magnetic flux transmitted to the first annular wall 72. This makes it possible to reduce the lateral force generated between the first annular protrusion 52 and the first annular wall 72.

[0099] Furthermore, because the first top surface 52b and the first bottom surface 71a each extend in the radial direction, the proportion of the axial component is greater than that of the magnetic flux generated in the other attraction portions. In other words, a stronger attraction force is likely to be generated between the first top surface 52b and the first bottom surface 71a than in the other attraction portions.

[0100] Furthermore, because the first top surface 52b and the first bottom surface 71a are substantially parallel, the components of the transmitted magnetic flux are less likely to change depending on the stroke, and therefore the second top surface 52c and the second bottom surface 71b continue to contribute to an increase in the attractive force while the magnetic flux is being transmitted.

[0101] Furthermore, when the movable core 70 moves further toward the second fixed core 50 , the tip of the second annular wall portion 73 begins to enter the recessed portion 56 of the annular groove portion 54 .

[0102] As a result, the outer diameter side surface 52d of the first annular protrusion 52 and the inner diameter side surface 73a of the second annular wall portion 73 overlap in the radial direction, and magnetic flux is transmitted from the outer diameter side surface 52d to the inner diameter side surface 73a. The magnetic flux transmitted between them has a large radial component.

[0103] 4 , in this state, the rate of increase of the magnetic flux that is guided from the base 51 to the first annular protrusion 52 and transmitted from its outer diameter side surface 52d to the inner diameter side surface 73a of the second annular wall portion 73 is relatively greater than the rate of increase of the magnetic flux transmitted between the second top surface 52c and the second bottom surface 71b, the rate of increase of the magnetic flux transmitted between the first top surface 52b and the first bottom surface 71a, and the rate of increase of the magnetic flux transmitted to the first annular wall portion 72. This makes it less likely that an excessive attractive force will be generated at the end of the stroke.

[0104] 5, when the tip of the second annular wall portion 73 enters the recessed portion 56 in the annular groove portion 54 and abuts against the stopper 55, the movement of the movable core 70 is restricted and the movable core 70 is brought into a state of being closest to the second fixed core 50. In the present invention, the axial distance at which the movable core 70 is closest to the second fixed core 50 is defined as the minimum stroke.

[0105] The shortest distance between the inner diameter side surface 52a and the outer diameter side surface 72c at the minimum stroke is defined as distance L1. The shortest distance between the second top surface 52c and the second bottom surface 71b is defined as distance L2. The shortest distance between the outer diameter side surface 52d and the inner diameter side surface 73a is defined as distance L3. The shortest distance between the inner diameter side surface 53a and the outer diameter side surface 73c is defined as distance L4. These distances L1 to L4 are all substantially the same (L1 = L2 = L3 = L4).

[0106] The shortest distance between the first top surface 52b and the first bottom surface 71a is defined as distance L5, which is slightly longer than the above-described distances L1 to L4 (L1=L2=L3=L4<L5).

[0107] This prevents excessive magnetic flux from being transmitted between the first top surface 52b and the first bottom surface 71a at the end of the stroke of the movable core 70, thereby preventing a sudden increase in thrust. Note that the second top surface 52c and the second bottom surface 71b, and the first top surface 52b and the first bottom surface 71a may be configured to abut, but from the viewpoint of preventing a sudden increase in thrust, it is preferable to leave a gap between the first top surface 52b and the first bottom surface 71a. The same applies to the other opposing surfaces.

[0108] Furthermore, distance L6 is the shortest distance between the bottom surface 54a of the second fixed core 50 and the top surface 73b of the second annular wall portion 73. Distance L6 is approximately five times the above-mentioned distance L5 (L1 = L2 = L3 = L4 < L5 << L6).

[0109] As a result, magnetic flux is less likely to be transmitted from the bottom surface 54a to the top surface 73b at the end of the stroke of the movable core 70, preventing a sudden increase in thrust. In other words, the bottom surface 54a and the top surface 73b are configured so as not to function as opposed-magnetic-pole-type attracting portions. Note that the bottom surface 54a and the top surface 73b only need to be spaced apart enough so as not to function as opposed-magnetic-pole-type attracting portions, and the distance L6 may be changed as appropriate.

[0110] Furthermore, the bottom surface 54 a and the top surface 73 b are both surfaces perpendicular to the stroke direction. With this simple configuration, the bottom surface 54 a and the top surface 73 b can be disposed at a distance that makes it difficult for magnetic flux to be transmitted in both the radial and circumferential directions.

[0111] Here, the measurement results of the change in thrust force [N] relative to the stroke [mm] for each current value [A] will be described with reference to FIG.

[0112] In the case of 0.2 A, the thrust tends to increase towards the end of the stroke 2 (see FIG. 5), but the change is smooth.

[0113] Furthermore, in the cases of 0.4 A and 0.6 A, the thrust tends to increase more easily in the early stage (see FIG. 2) than in the case of 0.2 A, but the change is smooth.

[0114] Furthermore, in the cases of 0.8 A and 1.0 A, the thrust force gradually decreased and changed smoothly. In particular, at the end of the stroke (see Figures 4 and 5), the thrust force changed more smoothly than in the cases of 0.2 A to 0.6 A.

[0115] Furthermore, compared to the results of the solenoid device 110 described below, at all current values, a high thrust force [N] was obtained from immediately after the start of current flow (see Figure 2) until just before the movable iron core 70 came closest to the second fixed iron core 50 (see Figure 5).

[0116] Furthermore, in the case of high current values ​​such as 0.6 A, 0.8 A, and 1.0 A, the increase in thrust [N] was suppressed more than in the case of the solenoid device 110 at the end of the stroke (see between FIGS. 4 and 5).

[0117] As described above, in the solenoid device 10 of this embodiment, the second fixed core 50 has the second annular protrusion 53 that is arranged in parallel with the first annular protrusion 52 and has a different height.

[0118] This allows the attractive force generated between the movable iron core 70 as the mating iron core and the first annular convex portion 52, and the attractive force generated between the movable iron core 70 and the second annular convex portion 53 to be generated and changed in stages. This allows the thrust to transition smoothly with respect to the stroke, thereby simplifying control.

[0119] Furthermore, the first annular protrusion 52 overlaps the movable core 70 in the radial direction at the maximum stroke, thereby enabling a high thrust to be generated from the beginning of the stroke.

[0120] The tip of the first annular protrusion 52 has a tapered shape that narrows toward the inner diameter side, which allows the suction force generated between the first annular protrusion 52 and the second annular wall 73 and the suction force generated between the first annular protrusion 52 and the first annular wall 72 to be generated and changed in stages.

[0121] The tip of the first annular protrusion 52 has a tapered shape that narrows radially away from the second annular protrusion 53. This allows the suction force generated between the first annular protrusion 52 and the second annular wall 73 and the suction force generated between the second annular protrusion 53 and the second annular wall 73 to be generated and changed in stages.

[0122] Furthermore, the first annular protrusion 52 is higher than the second annular protrusion 53. This allows the suction force generated between the first annular protrusion 52 and the second annular wall 73, the suction force generated between the first annular protrusion 52 and the first annular wall 72, and the suction force generated between the second annular protrusion 53 and the second annular wall 73 to be generated and changed in stages.

[0123] Furthermore, the tip of the second annular protrusion 53 has a tapered shape that narrows radially toward the movable core 70. In other words, the second annular protrusion 53 has a tapered shape in which the outer diameter of its top surface 53b is smaller than the outer diameter of the top surface 153b of the second annular protrusion 153 of Example 2, which will be described later. This makes it easier for the second annular protrusion 53 to guide magnetic flux toward the inner diameter side more smoothly than the second annular protrusion 153, and therefore makes it less likely for magnetic flux with a large radial component to be generated than with the second annular protrusion 153. In other words, it is easier to reduce the generation of lateral forces.

[0124] A solenoid device according to a second embodiment will be described with reference to Figures 7 to 10. Note that a description of the same configuration as in the first embodiment will be omitted.

[0125] 7, in the solenoid device 110 of the present embodiment, the shapes of the first fixed core 130, the spacer 140, the second fixed core 150, and the movable core 170 are different from those of the first embodiment. Hereinafter, the second fixed core 150 and the movable core 170, which are factors that cause the magnetic flux transmission mode to differ from that of the first embodiment, will be described.

[0126] As shown in FIG. 8 , the second stator core 150 has a first annular convex portion 152 and a second annular convex portion 153 .

[0127] The first annular protrusion 152 has a second top surface 152c that extends axially to the left with a substantially uniform thickness and then tapers from the inner diameter side to the outer diameter side.

[0128] The second annular protrusion 153 extends axially to the left with approximately the same thickness. The second annular protrusion 153 has a top surface 153b extending radially. The second annular protrusion 153 also protrudes axially to the left beyond the first annular protrusion 152. In other words, the second annular protrusion 153 is taller than the first annular protrusion 152.

[0129] The movable core 170 has a first annular wall portion 172 and a second annular wall portion 173 .

[0130] The first annular wall portion 172 has a tapered shape that tapers from the outer diameter side to the inner diameter side and extends toward the right in the axial direction. The first annular wall portion 172 has a second bottom surface 171b that slopes from the outer diameter side to the inner diameter side and extends toward the right in the axial direction. The second bottom surface 171b faces the second annular wall portion 173.

[0131] The second annular wall portion 173 extends axially to the right with a substantially uniform thickness.

[0132] Immediately after the solenoid device 110 is energized, an attractive force is generated between the first annular protrusion 152 and the second annular wall portion 173. In addition, an attractive force and a lateral force are generated between the second annular protrusion 153 and the second annular wall portion 173.

[0133] 9, when the movable core 170 moves toward the second fixed core 150 from the state shown in FIG. 8, a lateral force is also generated between the first annular protrusion 152 and the second annular wall portion 173. The magnetic flux transmitted between the first annular protrusion 152 and the second annular wall portion 173 and the magnetic flux transmitted between the second annular protrusion 153 and the second annular wall portion 173 have opposing radial components, which reduces the lateral force.

[0134] Furthermore, when the movable iron core 170 moves toward the second fixed iron core 150 , an attractive force is also generated between the first annular protrusion 152 and the first annular wall portion 172 .

[0135] 9, the second annular wall portion 173 abuts against the stopper 55, restricting axial movement. In this state, the second annular wall portion 173 and the annular groove portion 154 are spaced apart from each other in the axial direction, and transmission of magnetic flux from the bottom surface 154 a to the top surface 173 b is inhibited.

[0136] Here, the measurement results of the change in thrust force [N] relative to the stroke [mm] for each current value [A] will be described with reference to FIG.

[0137] In the case of 0.2 A, the thrust force increased gradually and smoothly from immediately after the start of energization until immediately before the movable iron core 170 came closest to the second fixed iron core 150 .

[0138] In addition, in the cases of 0.4 A and 0.6 A, the thrust tends to increase more easily than in the case of 0.2 A, but the change is smooth.

[0139] Furthermore, in the cases of 0.8 A and 1.0 A, the thrust tends to increase more easily in the early and late stages than in the cases of 0.2 A to 0.6 A, but the transition was smooth in the middle stages.

[0140] On the other hand, the solenoid device 110 has a lower thrust [N] at any current value compared to the solenoid device 10 of Example 1. This makes it easier for the solenoid device 110 to perform more precise control than the solenoid device 10 of Example 1.

[0141] As described above, if the annular recess 171 of the movable core 170 and the first annular protrusion 152 of the second fixed core 150 can be arranged in a nested state, and the heights of the first annular protrusion 152 and the second annular protrusion 153 are different, the thrust can be smoothly transitioned with respect to the stroke. This simplifies control. In other words, as long as the annular recess and the annular protrusion can be arranged in a nested state, and the heights of the annular protrusion and the second annular protrusion are different, other structural changes may be made as appropriate.

[0142] Although the embodiments of the present invention have been described above with reference to the drawings, the specific configuration is not limited to these embodiments, and the present invention also includes modifications and additions that do not deviate from the gist of the present invention.

[0143] For example, in the above-described Examples 1 and 2, a configuration in which an annular recess is formed on the movable iron core and an annular protrusion is formed on the fixed iron core is described, but this is not limited to this, and an annular protrusion may be formed on the movable iron core and an annular recess may be formed on the fixed iron core.

[0144] In the first embodiment, the first annular protrusion 52 and the first annular wall 72 overlap in the radial direction, and the second annular protrusion 53 and the second annular wall 73 are spaced apart in the axial direction at the maximum stroke. However, this is not limiting, and not only the second annular protrusion 53 and the second annular wall 73 but also the first annular protrusion 52 and the first annular wall 72 may be spaced apart in the axial direction. Similarly, not only the first annular protrusion 52 and the first annular wall 72 but also the second annular protrusion 53 and the second annular wall 73 may overlap in the radial direction.

[0145] Furthermore, in the above-described first embodiment, the first annular convex portion 52 has been described as having a linear tapered shape with a slope extending in a straight line, but this is not limited to this, and it may have a curved tapered shape with a slope extending in a curved line, or a stepped tapered shape with a slope extending in a stepped manner, and the details may be changed as appropriate as long as it tapers toward the inner diameter side or the outer diameter side.

[0146] Furthermore, in Examples 1 and 2, the fixed core is described as being divided into a first fixed core and a second fixed core, but this is not limited to this. For example, the cylindrical portion of the first fixed core and the second annular convex portion of the second fixed core may be connected by a thin-walled portion.

[0147] In addition, in the first and second embodiments, the second fixed core is described as being an integrally molded product having the first annular convex portion and the second annular convex portion, but this is not limited thereto, and for example, the first annular convex portion may be a single cylindrical member that is fitted into a cylindrical member having a separate second annular convex portion.

[0148] 10 Solenoid device 21 Coil 30 First stationary iron core (stationary iron core) 50 Second stationary iron core (stationary iron core) 52 First annular convex portion (annular convex portion) 52a Side surface 52b First top surface (top surface) 52c Second top surface (top surface, inclined surface) 52d Side surface 53 Second annular convex portion 53a Side surface 54 Annular groove portion 54a Bottom surface 70 Movable iron core 71 Annular recess 71b Second bottom surface (bottom surface) 72 First annular wall portion (other annular wall portion) 72c Side surface 73 Second annular wall portion (one annular wall portion) 73a Side surface 73b Top surface 73c Side surface 110 Solenoid device 130 First stationary iron core (stationary iron core) 150 Second stationary iron core (stationary iron core) 152 First annular protrusion (annular protrusion) 152c Second top surface (top surface) 153 Second annular protrusion 170 Movable iron core 171 Annular recess 171b Second bottom surface (bottom surface) 172 First annular wall (other annular wall) 173 Second annular wall (one annular wall)

Claims

1. A solenoid device in which a movable iron core is attracted to and moves towards a fixed iron core when current is passed through a coil, wherein one of the movable iron core and the fixed iron core has an annular recess, and the other of the movable iron core and the fixed iron core has an annular protrusion that can be nested within the annular recess, and a second annular protrusion of a different height that is arranged alongside the annular protrusion.

2. The solenoid device according to claim 1, wherein at least one of the annular protrusion and the second annular protrusion overlaps radially with the mating iron core at maximum stroke.

3. A solenoid device according to claim 1 or 2, wherein the tip of said annular projection is tapered.

4. A solenoid device according to claim 3, wherein the tip of said annular protrusion is tapered in the radial direction away from said second annular protrusion.

5. The solenoid device according to claim 4, wherein the annular protrusion is higher than the second annular protrusion.

6. A solenoid device as described in claim 5, wherein the second annular protrusion faces only one of the inner and outer annular wall portions that form the annular recess, and is axially separated from the one annular wall portion at maximum stroke.

7. A solenoid device according to claim 1, wherein the tip of said second annular projection is tapered radially toward the opposing iron core.

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