Electromagnetic actuator

Abstract

To provide an electromagnetic actuator capable of simplifying a structure, reducing frictional resistance or the like without increasing the number of components, and ensuring a desired operation by surely interlocking a shaft with a movable element.SOLUTION: The electromagnetic actuator includes a solenoid unit (U) including a movable member (70) configured to reciprocate along an axis (S), a stationary member (30405060) forming a magnetic path, and an exciting coil (80), a cylindrical shaft (90) configured to move integrally with the movable member (70), and a guide member (100) configured to reciprocatably guide the shaft (90), wherein the shaft (90) is made of a non-magnetic material and is connected to the movable member (70) with predetermined play margins (C1, C2, C3).SELECTED DRAWING: Figure 6

Description

[Technical Field]

[0001] The present invention relates to an electromagnetic actuator that uses the electromagnetic force of a solenoid as a driving force, and more particularly to an electromagnetic actuator that has a shaft that moves integrally with a mover to exert a driving force on the outside. [Background technology]

[0002] A known conventional electromagnetic actuator is an electromagnetic drive device that includes an excitation coil, a core unit that forms a magnetic path as a stator, an armature unit that incorporates an armature tappet portion and permanent magnet as a mover that reciprocates relative to the stator in a predetermined axial direction when current is applied to the coil, and a tappet unit that is a shaft that includes a magnetic portion that is attracted to the permanent magnet of the armature unit (see, for example, Patent Document 1).

[0003] In this electromagnetic drive device, the tappet unit is attracted by magnetic force to the permanent magnet of the armature unit, and moves integrally with the mover. Therefore, since the tappet unit must be magnetic at least in the area that engages with the armature unit, it must be formed, for example, using soft iron and undergo a material change treatment to make the tip area hard, or it must be formed by joining a magnetic material and a wear-resistant material by welding or the like.

[0004] Another known electromagnetic actuator is an electromagnetic drive device that includes an excitation coil, a yoke that forms a magnetic path as a stator, an armature tappet section as a mover that reciprocates relative to the stator in a predetermined axial direction when current is passed through the coil, an armature section that incorporates a permanent magnet, a tappet unit as a shaft that includes a magnetic section that is attracted to the permanent magnet in the armature section, and a housing section that guides the tappet unit so that it can reciprocate freely (see, for example, Patent Document 2).

[0005] In this electromagnetic drive device, as in the above, the tappet unit is attracted by magnetic force to the permanent magnet of the armature portion, and moves integrally with the mover. Therefore, at least the area of ​​the tappet unit that engages with the armature portion needs to be made of a magnetic material, and if the housing portion is made of a magnetic material, a magnetic path will be formed between the tappet unit and the housing portion, generating a magnetic force that attracts the tappet unit to the housing portion, which may result in an increase in frictional resistance and resistance load when the tappet unit moves. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Laid-Open No. 2011-530028 [Patent Document 2] Japanese Patent Application Laid-Open No. 2010-530621 Summary of the Invention [Problem to be solved by the invention]

[0007] The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an electromagnetic actuator that can simplify the structure, reduce frictional resistance and resistance load, and ensure the desired operation by reliably linking the shaft with the mover without increasing the number of parts. [Means for solving the problem]

[0008] The electromagnetic actuator of the present invention comprises a solenoid unit including a mover that reciprocates along a predetermined axis, a stator that forms a magnetic path, and an excitation coil; a cylindrical shaft that moves integrally with the mover; and a guide member that guides the shaft so that it can reciprocate freely, the shaft being made of a non-magnetic material and connected to the mover with a predetermined play.

[0009] In the above electromagnetic actuator, the mover may include a cylindrical plunger extending in the axial direction and a disk member fixed to the end of the plunger, the disk member including a slit extending in a direction perpendicular to the axis, and the shaft including a neck portion inserted into the slit and a head portion having an outer diameter larger than that of the neck portion.

[0010] In the electromagnetic actuator, the shaft may be coupled to the disk member on an offset axis that is offset parallel to the axis.

[0011] In the above electromagnetic actuator, the disk member may include a first disk, a second disk, a cylindrical ring interposed between the first disk and the second disk, and a permanent magnet sandwiched between the first disk and the second disk inside the ring, and the second disk may include a slit that is cut out radially outward on an orthogonal line perpendicular to the axis.

[0012] In the above electromagnetic actuator, the guide member may be formed from a magnetic material, and the mover may be configured to selectively stop at a retracted position where the disk member is attracted to a part of the stator and at an advanced position where the disk member is attracted to the guide member due to the magnetic force exerted by the permanent magnet when the coil is not energized.

[0013] In the above electromagnetic actuator, the disk member may include an abutment plate that abuts against a part of the stator in the retracted position, the first disk and the second disk being formed of a magnetic material, and the abutment plate being formed of a non-magnetic material.

[0014] In the electromagnetic actuator, the ring may be configured such that, when the neck portion of the shaft is inserted into the slit and assembled, the inner wall surface of the ring faces the head portion to prevent the shaft from falling off.

[0015] In the electromagnetic actuator, the neck portion may be inserted into the slit with a first play in the width direction of the slit.

[0016] In the electromagnetic actuator, a configuration may be adopted in which the neck portion is inserted into the slit with a second play in the direction of the offset axis.

[0017] In the electromagnetic actuator, the permanent magnet may have a hollowed-out portion for receiving the head in a non-contact manner.

[0018] In the above electromagnetic actuator, the stator may be configured to include a cylindrical inner yoke that accommodates the plunger of the movable element so that it can move back and forth, an outer yoke that surrounds a coil arranged around the inner yoke, a rear yoke that joins the inner yoke and the outer yoke, and a front yoke that joins the guide member and the outer yoke.

[0019] The electromagnetic actuator may include a resin housing that surrounds the solenoid unit, and the housing may be joined to the front yoke.

[0020] In the above electromagnetic actuator, the solenoid unit may include a first solenoid unit and a second solenoid unit arranged adjacent to each other and parallel to each other, the shaft may include a first shaft connected to the movable element of the first solenoid unit and a second shaft connected to the movable element of the second solenoid unit, and the guide member may include a first guide passage that guides the first shaft so that it can move back and forth, and a second guide passage that guides the second shaft so that it can move back and forth.

[0021] In the above electromagnetic actuator, the first shaft and the second shaft may be arranged biased toward each other in the direction of an orthogonal line perpendicular to the axis of the first solenoid unit and the axis of the second solenoid unit.

[0022] In the above electromagnetic actuator, the stator may include a cylindrical inner yoke that accommodates the plunger of the movable element so that it can move back and forth, an outer yoke that surrounds a coil arranged around the inner yoke, a rear yoke that joins the inner yoke and the outer yoke, and a front yoke that joins the guide member, and the outer yoke of the first solenoid unit and the outer yoke of the second solenoid unit may be curved plates that include cutout portions cut out so that their cross sections perpendicular to the axis are C-shaped, and the respective cutout portions may be arranged adjacent to each other and facing each other.

[0023] In the above electromagnetic actuator, a configuration may be adopted in which the rear yoke of the first solenoid unit and the rear yoke of the second solenoid unit are a common rear yoke integrally formed as a single member, and the front yoke of the first solenoid unit and the front yoke of the second solenoid unit are a common front yoke integrally formed as a single member.

[0024] The electromagnetic actuator may include a resin housing that surrounds the first solenoid unit and the second solenoid unit, and the housing may be joined to a common front yoke. [Effects of the Invention]

[0025] According to the electromagnetic actuator having the above configuration, it is possible to simplify the structure, reduce frictional resistance and resistance load, and the like, without increasing the number of parts, and it is possible to reliably link the shaft with the movable element, ensuring the desired operation. [Brief explanation of the drawings]

[0026] [Figure 1] 1 is a perspective view showing an external appearance of an electromagnetic actuator according to an embodiment of the present invention, viewed obliquely from one direction. [Figure 2] 10 is a perspective view showing an electromagnetic actuator according to an embodiment, as viewed from another direction (the side to be attached to an application object). FIG. [Figure 3] FIG. 1 is an exploded perspective view of an electromagnetic actuator according to an embodiment. [Figure 4] FIG. 1 is an exploded perspective view of an electromagnetic actuator according to an embodiment. [Figure 5] 1 is a cross-sectional view of an electromagnetic actuator according to one embodiment, taken along a center plane that bisects a first solenoid unit and a second solenoid unit. [Figure 6] 2 is a cross-sectional view of an electromagnetic actuator according to one embodiment, taken along a plane including the axis of a mover included in a first solenoid unit and the axis of a mover included in a second solenoid unit. FIG. [Figure 7] 3 is a cross-sectional view of an electromagnetic actuator according to one embodiment, taken along a plane perpendicular to the axis of a mover included in a first solenoid unit and the axis of a mover included in a second solenoid unit. FIG. [Figure 8] 1 is an exploded perspective view of a solenoid unit (excluding a mover, a coil, and a part of a stator) included in an electromagnetic actuator according to one embodiment. FIG. [Figure 9] 1 is an external perspective view showing a mover and a shaft included in an electromagnetic actuator according to an embodiment; [Figure 10] FIG. 10 is an exploded perspective view of the mover and the shaft shown in FIG. 9. [Figure 11] 10 is a partial cross-sectional view of the mover and shaft shown in FIG. 9, taken along a plane including the axis of the plunger of the mover and the offset axis of the shaft. [Figure 12] 10 is a cross-sectional view of the mover and shaft shown in FIG. 9, in which a disk member forming a part of the mover is cut along a plane perpendicular to the axis. [Figure 13] FIG. 12 is an enlarged cross-sectional view showing a part of the cross-sectional view shown in FIG. 11 . [Figure 14] 10 is an enlarged cross-sectional view of the mover and shaft shown in FIG. 9, taken along a plane including the offset axis of the shaft. FIG. [Figure 15] 10A and 10B are schematic diagrams illustrating the operation of a shaft when an electromagnetic actuator according to an embodiment is applied to an application object. [Figure 16] 10A and 10B are schematic diagrams illustrating the operation of a shaft when an electromagnetic actuator according to an embodiment is applied to an application object. [Figure 17] 10A and 10B are schematic diagrams illustrating the operation of a shaft when an electromagnetic actuator according to an embodiment is applied to an application object. [Figure 18] 10 is a graph showing a resistive load applied to a shaft in an electromagnetic actuator according to an embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0027] Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings. The electromagnetic actuator according to the present invention is applied to an object that exerts a driving force on the outside, such as a camshaft switching mechanism that switches cams by displacing the camshaft of an internal combustion engine in the axial direction.

[0028] As shown in Figures 1 to 4, an electromagnetic actuator according to one embodiment includes a housing H, a first solenoid unit U1 and a second solenoid unit U2 as solenoid units U, a shaft 90 as a first shaft V1 connected to the first solenoid unit U1 and a second shaft V2 connected to the second solenoid unit U2, and a guide member 100 that guides the shaft 90 so that it can move back and forth.

[0029] Here, the housing H is composed of a housing body 10 made of resin and a housing cover 20 made of resin. The solenoid unit U also includes an inner yoke 30, an outer yoke 40, a rear yoke 50, and a front yoke 60 as stators that form a magnetic path, a movable element 70 that moves along the axis S (S1, S2) direction, and an excitation coil 80. Furthermore, the first solenoid unit U1 is centered on the axis S1, and the second solenoid unit U2 is centered on the axis S2, and the first solenoid unit U1 and the second solenoid unit U2 are arranged adjacent to each other and parallel to each other, i.e., the axis S1 and the axis S2 are arranged parallel to each other.

[0030] The housing body 10 is molded using a resin material in a mold, and as shown in Figures 3 to 6, it has a flange portion 11, a wall portion 12, an opening 13, and a connector 14 connected to the wall portion 12. The flange portion 11 includes a joining surface 11a to which the front yoke 60 is joined, an annular groove 11b into which the seal member Sr1 is fitted, and two boss portions 11c on which metal collars (not shown) are insert-molded. The wall portion 12 defines a space for accommodating the first solenoid unit U1 and the second solenoid unit U2, and has a plurality of reinforcing ribs 12a protruding from the outer wall surface. When the housing main body 10 is molded using a mold, the rear yoke 50 is insert-molded into the wall portion 12 so that the peripheral region of the rear yoke 50 is embedded in the inner region of the wall portion 12. The connector 14 is formed so as to expose and surround the terminals (not shown) that electrically connect the ends of the coils 80 included in the first solenoid unit U1 and the second solenoid unit U2, and to bury the base areas thereof.

[0031] The housing cover 20 is molded using a resin material in a mold, and the inner yoke 30 and outer yoke 40 holding the coil 80 are connected to the rear yoke 50, which is insert-molded integrally with the housing main body 10, and fixed by crimping or the like.The housing cover 20 is then joined to the housing main body 10 and fixed by vibration welding or the like so as to close the opening 13.

[0032] The inner yoke 30 is formed into a cylindrical shape by machining or forging using a magnetic material such as soft iron, and functions as a magnetic path through which magnetic lines of force pass. As shown in Figures 6 and 8, the inner yoke 30 comprises a cylindrical portion 31, a fitting portion 32, and an annular flange portion 33. The cylindrical portion 31 has an inner peripheral surface 31a and an outer peripheral surface 31b centered on the axis S (S1, S2). The inner peripheral surface 31a accommodates the plunger 70a of the mover 70 so that it can reciprocate in the direction of the axis S (S1, S2). The outer peripheral surface 31b is formed so that the cylindrical portion 81a of the bobbin 81 around which the coil 80 is wound is fitted. The fitting portion 32 is fitted into a fitting hole 51 of the rear yoke 50 and fixed thereto. The annular flange 33 functions as part of the stator that is attracted to the disk member 70b of the mover 70 by magnetic force, and has an annular end surface 33a perpendicular to the axis S (S1, S2) and a conical surface 33b that receives the bobbin 81. The annular end surface 33a abuts against an abutment plate 75 that forms part of the disk member 70b of the mover 70, and also functions as a stopper that positions the disk member 70b at the retracted position.

[0033] The outer yoke 40 is formed into a cylindrical shape by machining or forging using a magnetic material such as soft iron, and functions as a magnetic path through which magnetic lines of force pass.As shown in Figures 5 to 8, the outer yoke 40 is formed into a cylindrical shape centered on the axis S (S1, S2) with a portion cut out so as to surround the coil 80 arranged around the inner yoke 30. Specifically, the outer yoke 40 is formed to be a curved plate including a cutout portion 41 cut out so that the cross section perpendicular to the axis S (S1, S2) is C-shaped, a mating piece 42 that fits into a mating hole 52 of the rear yoke 50, an end face 43 arranged close to the front yoke 60, and a cutout portion 44 that opens toward the end face 43 on the side opposite the cutout portion 41.

[0034] The outer yoke 40 is fitted onto the flange 81b of the bobbin 81 so as to surround the coil 80, and the fitting piece 42 is fitted into the fitting hole 52 of the rear yoke 50 and fixed. In addition, as shown in Figure 7, the outer yoke 40 of the first solenoid unit U1 and the outer yoke 40 of the second solenoid unit U2 are arranged so that their respective cutout portions 41, 41 are adjacent and face each other in the direction of an orthogonal line L1 that is perpendicular to the axes S1, S2. In this way, by providing the cutout portion 41, the first solenoid unit U1 and the second solenoid unit U2 can be arranged close to each other in the direction of the orthogonal line L1, and the overall size can be reduced by consolidating the parts.

[0035] The rear yoke 50 is formed into a long, flat plate by machining or forging using a magnetic material such as soft iron, and functions as a magnetic path for passing magnetic lines of force, as well as positioning the first solenoid unit U1 and the second solenoid unit U2 relative to each other; in other words, it functions as a common rear yoke in which each rear yoke is integrally formed as a single member. 3, 6, and 8, the rear yoke 50 has two fitting holes 51 centered on the axes S1 and S2, respectively, and a plurality of fitting holes 52 around the fitting holes 51. The fitting portions 32 of the inner yoke 30 are fitted into the fitting holes 51, and the fitting pieces 42 of the outer yoke 40 are fitted into the fitting holes 52. The rear yoke 50 serving as a common rear yoke is insert-molded together with the housing body 10 when the housing body 10 is molded using a mold, so that the peripheral region of the rear yoke 50 is embedded in the housing body 10 .

[0036] The front yoke 60 is formed into a flat plate shape by machining or forging using a magnetic material such as soft iron, and functions as a magnetic path through which magnetic lines of force pass, as well as a common front yoke in which the front yokes of the first solenoid unit U1 and the second solenoid unit U2 are integrally formed as a single member. As shown in FIGS. 3, 4, and 6, the front yoke 60 has a circular fitting hole 61 into which the guide member 100 is fitted, and two circular holes 62. The fitting portion 101 of the guide member 100 is fitted into the fitting hole 61 and is fixed integrally by appropriate welding or the like.

[0037] After the first solenoid unit U1 and the second solenoid unit U2 are assembled into the housing main body 10, the front yoke 60 is joined to the joining surface 11a of the flange portion 11 and the end of the collar (not shown) of the boss portion 11c is fitted into the circular hole 62 and crimped, thereby being fixed integrally with the housing main body 10.

[0038] As shown in FIGS. 9 to 11, the mover 70 is made up of a cylindrical plunger 70a extending in the direction of the axis S (S1, S2), and a disk member 70b fixed to the end of the plunger 70a. The plunger 70a functions as a magnetic path for passing magnetic lines of force and also functions as a movable iron core that moves in the direction of the axis S (S1, S2) when current is applied to the coil 80. It is formed into a cylindrical shape by machining or forging using a magnetic material, such as free-cutting steel (SUM).

[0039] The disk member 70b has a circular outer contour centered on the axis S (S1, S2), and includes a first disk 71, a second disk 72, a ring 73, a permanent magnet 74, and a contact plate 75. The first circular plate 71 is made of a magnetic material and has a circular fitting hole 71a centered on the axis S (S1, S2) and an outer circumferential stepped portion 71b. The second circular plate 72 is made of a magnetic material and has a circular fitting hole 72a centered on the axis S (S1, S2), an outer circumferential stepped portion 72b, and a slit 72c. The slit 72c is an area that connects the shaft 90 and extends in a direction perpendicular to the axis S (S1, S2). Here, as shown in FIG. 12, the slit 72c extends on an orthogonal line L2 that is perpendicular to the axis S (S1, S2) and is cut out radially outward.

[0040] The ring 73 is formed in a cylindrical shape and is disposed between the first disk 71 and the second disk 72 so that both ends thereof fit into the outer circumferential stepped portions 71b, 72b. The permanent magnet 74 is magnetized to generate magnetic lines of force in the direction of the axis S (S1, S2), and has a through hole 74a centered on the axis S (S1, S2) and a hollowed-out portion 74b that receives the head 92 of the shaft 90 without contact. The contact plate 75 is made of a non-magnetic material and has a circular fitting hole 75a centered on the axis S (S1, S2).

[0041] In the disk member 70b having the above configuration, the neck portion 91 of the shaft 90 is inserted into the slit 72c of the second disk 72, a ring 73 is stacked on the second disk 72, a permanent magnet 74 is placed inside the ring 73, the first disk 71 is stacked as the ring 73 so as to cover the permanent magnet 74, and an abutment plate 75 is stacked on the upper surface of the first disk 71. Then, as shown in FIG. 11, the ends of the shaft 90 are fitted into the fitting holes 75a and 71a, passed through the through hole 74a, fitted into the fitting hole 72a, and fixed to the abutment plate 75, the first circular plate 71, and the second circular plate 72 by welding or the like.

[0042] The coil 80 is a solenoid that generates a magnetic field when energized, and is wound around a bobbin 81 as shown in FIGS. The bobbin 81 is molded using a resin material and includes a cylindrical portion 81a and two opposing flange portions 81b as shown in Fig. 6. The bobbin 81, with the coil 80 wound around the cylindrical portion 81a, has the cylindrical portion 31 of the inner yoke 30 fitted inside the cylindrical portion 81a, and the flange portions 81b fitted inside the outer yoke 40, so that the bobbin 81 is held immovably by the inner yoke 30, the outer yoke 40, and the rear yoke 50.

[0043] The shaft 90 is formed in a cylindrical shape from a non-magnetic material, for example, stainless steel such as SUS305, and as shown in FIGS. 10 to 14, has a neck portion 91 and a head portion 92 in the end region. The neck portion 91 is formed to have a smaller diameter than the outer circumferential surface 90a. The head 92 has an outer diameter that is larger than the outer diameter of the neck 91 and slightly smaller than the outer diameter of the outer circumferential surface 90a, and is formed so that the outer circumferential edge region forms a convex curved surface. As described above, the neck portion 91 of the shaft 90 is inserted into the slit 72c of the disk member 70b, and the shaft 90 is connected to the disk member 70b of the movable member 70 on the offset axis D (D1, D2) that is offset parallel to the axis S (S1, S2).

[0044] Here, the shaft 90 is connected to the mover 70 with a predetermined play. Specifically, as shown in Figure 12, the neck portion 91 of the shaft 90 is inserted into the slit 72c with a gap C1 (C1 / 2 + C1 / 2) as a first play in the width direction of the slit 72c, and also with a gap C3 in the length direction of the slit 72c (direction of the perpendicular line L2). As shown in FIG. 13, the neck portion 91 of the shaft 90 is inserted into the slit 72c with a gap C2 as a second play in the direction of the offset axis D (D1, D2). As shown in FIG. 13, when the neck portion 91 of the shaft 90 is inserted into the slit 72c and assembled, the inner wall surface of the ring 73 faces the head portion 92 to prevent the shaft 90 from falling out. Furthermore, as shown in Figure 14, when the shaft 90 is inserted into the slit 72c and connected to the mover 70 with a predetermined amount of play, even if the shaft 90 moves within the play area, the head 92 does not come into contact with the hollowed-out portion 74b of the permanent magnet 74.

[0045] In this way, by connecting the shaft 90 to the movable member 70 with a predetermined play (gaps C1, C3), when the axis S (S1, S2) along which the plunger 70a of the movable member 70 moves is different from the axis along which the shaft 90 moves, i.e., when the shaft 90 moves on an offset axis D (D1, D2) that is offset parallel to the axis S (S1, S2), for example, when the shaft 90 is assembled based on the plunger 70a, it can be smoothly assembled into the first guide passage 102 and the second guide passage 103 of the guide member 100 that guides the shaft 90. Furthermore, since the shaft 90 is connected to the movable member 70 with a predetermined play (gap C2), the shaft 90 can be smoothly engaged with the engagement grooves G1, G2, for example, when there is variation in depth in the engagement grooves G1, G2 (see Figures 15 to 17) of the camshaft CS, which is the object of application.

[0046] The guide member 100 is formed into a cylindrical shape by machining or forging using a magnetic material, such as free-cutting steel (SUM), and as shown in Figures 2 to 5, it has a fitting portion 101, a first guide passage 102, a second guide passage 103, two recessed portions 104, an end face 105, and an annular groove 106. The fitting portion 101 is a region that is fitted into the fitting hole 61 of the front yoke 60 and fixed by welding or the like, and has an annular flange portion 101a. The first guide passage 102 is formed as a cylindrical passage extending about the offset axis D1, and guides the shaft 90 serving as the first shaft V1 so that it slides and reciprocates. The second guide passage 103 is formed as a cylindrical passage extending about the offset axis D2, and guides the shaft 90 serving as the second shaft V2 so that it slides and reciprocates. The two hollowed-out portions 104 are arranged in a direction perpendicular to the direction in which the first guide passage 102 and the second guide passage 103 are arranged, and are formed as through holes that extend parallel to the offset axes D1 and D2. The end face 105 is formed as a plane perpendicular to the axis S (S1, S2) and functions as a stopper that abuts the end face 70a1 of the plunger 70a of the movable member 70, positioning the disc member 70b at an advanced position where the disc member 70b is attracted to the guide member 100. The annular groove 106 is adapted to receive a seal member Sr2 that seals the gap with the fitting surface of the housing of the application object when the guide member 100 is fitted into the housing of the application object or the like.

[0047] Next, the operation of the electromagnetic actuator having the above-described structure when it is applied to a camshaft switching mechanism of an internal combustion engine will be described with reference to FIGS. First, in a non-energized state where the coil 80 is not energized, the first shaft V1 and the second shaft V2 are located in the retracted position as shown in Fig. 15. In this retracted position, the disk member 70b of the mover 70 is attracted to and held by the annular flange 33 of the inner yoke 30, which is part of the stator, with the abutment plate 75 abutting against the annular end face 33a.

[0048] When the camshaft CS is moved in the direction of arrow A1 along the axis A, the coil 80 of the first solenoid unit U1 is energized, as shown in Fig. 16. This causes the mover 70 to move by electromagnetic force, and the first shaft V1 protrudes to the forward position and engages with the engagement groove G1. The camshaft CS then moves in the direction of arrow A1 while rotating around the axis A, switching the cam.

[0049] During this switching operation, the coil 80 is de-energized, and the disk member 70b of the mover 70 is attracted to the guide member 100 and maintained in the forward position. When this switching operation is completed, the depth of the engagement groove G1 gradually becomes shallower, the first shaft V1 is pushed back by the groove bottom of the engagement groove G1 and moves toward the retracted position, and the disc member 70b of the movable member 70 is maintained in the retracted position as the abutment plate 75 abuts against the annular end face 33a and is adsorbed to the annular flange portion 33 of the inner yoke 30.

[0050] On the other hand, when the camshaft CS is moved in the direction of the arrow A2 along the axis A, the coil 80 of the second solenoid unit U2 is energized, as shown in Figure 17. This causes the mover 70 to move due to electromagnetic force, and the second shaft V2 protrudes to the forward position and engages with the engagement groove G2. Then, the camshaft CS moves in the direction of the arrow A2 while rotating around the axis A, switching the cam.

[0051] During this switching operation, the coil 80 is de-energized, and the disk member 70b of the mover 70 is attracted to the guide member 100 and maintained in the forward position. When this switching operation is completed, the depth of the engagement groove G2 gradually becomes shallower, the second shaft V2 is pushed back by the groove bottom of the engagement groove G2 and moves toward the retracted position, and the disc member 70b of the movable member 70 is maintained in the retracted position as the abutment plate 75 abuts against the annular end face 33a and is adsorbed to the annular flange portion 33 of the inner yoke 30. The operation of the electromagnetic actuator is not limited to the above method, and other operation methods may be applied.

[0052] As described above, the electromagnetic actuator according to the above embodiment comprises a solenoid unit U including a mover 70 that reciprocates along the axis S, a stator (inner yoke 30, outer yoke 40, rear yoke 50, front yoke 60) that forms a magnetic path, and an excitation coil 80, a cylindrical shaft 90 that moves integrally with the mover 70, and a guide member 100 that guides the shaft 90 so that it can reciprocate freely, and the shaft 90 is made of a non-magnetic material and is connected to the mover 70 with a predetermined play (gaps C1, C2, C3). According to this, when linking the shaft 90 to the mover 70 formed as a separate part, there is no need to link the shaft to the mover using magnetic force as in the past. By connecting the shaft 90 to the mover 70 with a predetermined amount of play, when the shaft 90 is guided in a guide passage (for example, the first guide passage 102, the second guide passage 103), it is possible to prevent galling and enable smooth operation, and the shaft 90 can be reliably linked to the mover 70 to ensure the desired function.

[0053] In addition, in the above embodiment, the movable member 70 includes a cylindrical plunger 70a extending in the direction of the axis S and a disk member 70b fixed to the end of the plunger 70a, the disk member 70b including a slit 72c extending in a direction perpendicular to the axis S, and the shaft 90 including a neck portion 91 inserted into the slit 72c and a head portion 92 having an outer diameter larger than that of the neck portion 91. According to this, the shaft 90 can be connected to the mover 70 simply by inserting the neck portion 91 into the slit 72c, and the structure can be simplified without increasing the number of parts.

[0054] In the above embodiment, the shaft 90 is connected to the disk member 70b on an offset axis D that is offset parallel to the axis S. This allows for easy adaptation to usage situations in which the axis S along which the movable element 70 moves and the axis along which the shaft 90 moves (offset axis D) are different, and the shaft 90 can be linked to the movable element 70 to ensure the desired functionality.

[0055] In addition, in the above embodiment, the disk member 70b of the movable member 70 includes a first disk 71, a second disk 72, a cylindrical ring 73 interposed between the first disk 71 and the second disk 72, and a permanent magnet 74 sandwiched between the first disk 71 and the second disk 72 inside the ring 73, and the second disk 72 includes a slit 72c, which is cut out radially outward on an orthogonal line L2 perpendicular to the axis S. This allows the disk member 70b to function as a magnetic path through which magnetic lines of force pass, and also allows the disk member 70b to be made smaller in diameter, more compact, and have a simpler structure, while also allowing the shaft 90 to be easily connected to the disk member 70b with a predetermined play (gaps C1, C2, C3).

[0056] Furthermore, in the above embodiment, the guide member 100 is formed of a magnetic material, and the movable member 70 is selectively stopped at a retracted position where the disc member 70b is attracted to a part of the stator (the annular flange portion 33 of the inner yoke 30) and an advanced position where the disc member 70b is attracted to the guide member 100 (in the region of the end face 105) due to the magnetic force exerted by the permanent magnet 74 when the coil 80 is not energized. According to this, the disk member 70b of the movable member 70 is selectively stopped at a retracted position or an advanced position by the magnetic force of the permanent magnet 74, so there is no need to use electromagnetic force generated by energizing the coil 80, thereby reducing power consumption. Furthermore, when the disk member 70b of the movable member 70 is stopped in the forward position, the magnetic field lines generated from the permanent magnet 74 flow directly to the guide member 100 without flowing through the shaft 90, so that if the shaft 90 is made of a magnetic material, no adhesive force is generated that would attract the shaft 90 to the guide member 100. Therefore, it is possible to prevent the generation of frictional resistance and resistance load due to magnetic force when the shaft 90 moves from the forward position to the backward position, and it is possible to move the shaft 90 and the mover 70 smoothly. 18 is a graph showing the resistance load (dotted line) when the shaft 90 is made of a magnetic material and the resistance load (solid line) when the shaft 90 is made of a non-magnetic material. The results show that the resistance load can be reduced over the entire stroke of the shaft 90.

[0057] In addition, in the above embodiment, the disk member 70b of the movable member 70 includes an abutment plate 75 that abuts against a part of the stator (the annular flange portion 33 of the inner yoke 30) in the retracted position, and the first disk 71 and the second disk 72 are formed of a magnetic material, and the abutment plate 75 is formed of a non-magnetic material. As a result, in the retracted position, the disk member 70b of the mover 70 contacts a part of the stator (the annular flange portion 33 of the inner yoke 30) via the abutment plate 75 made of a non-magnetic material, so that when current is passed through the coil 80 to start the mover 70, the magnetic force acting as resistance can be reduced, allowing the mover 70 to start quickly and smoothly.

[0058] In the above embodiment, when the neck portion 91 of the shaft 90 is inserted into the slit 72c and assembled, the inner wall surface of the ring 73 faces the head portion 92 to prevent the shaft 90 from falling off. With this, even if the shaft 90 is connected to the disk member 70b of the mover 70 with a predetermined play (gaps C1, C2, C3), the shaft 90 can be reliably prevented from falling off with a simple structure.

[0059] In the above embodiment, the neck portion 91 of the shaft 90 is inserted into the slit 72c with a first play (gap C1) in the width direction of the slit 72c. With this, when the plunger 70a of the movable member 70 is inserted into the cylindrical portion 31 of the inner yoke 30, the shaft 90 can be smoothly inserted into the first guide passage 102 and the second guide passage 103 of the guide member 100 without causing any galling or the like, and can also be smoothly reciprocated.

[0060] In the above embodiment, the neck portion 91 of the shaft 90 is inserted into the slit 72c with a second play (gap C2) in the direction of the offset axis D (D1, D2). According to this, when the shaft 90 is inserted into and engaged with the engagement grooves G1, G2 of the object to which it is applied, even if there is variation in the groove depth of the engagement grooves G1, G2 (areas shallower than the specified value), the shaft 90 can be smoothly adapted to the engagement grooves G1, G2 to achieve the desired function.

[0061] In the above embodiment, the permanent magnet 74 of the disk member 70b includes a hollowed-out portion 74b for receiving the head 92 of the shaft 90 in a non-contact manner. This allows the shaft 90 to move within the play range without restricting the movement of the head 92.

[0062] In addition, in the above embodiment, the stator includes a cylindrical inner yoke 30 that accommodates the plunger 70a of the movable member 70 so that it can move back and forth freely, an outer yoke 40 that surrounds the coil 80 arranged around the inner yoke 30, a rear yoke 50 that joins the inner yoke 30 and the outer yoke 40, and a front yoke 60 that joins the guide member 100 and the outer yoke 40. This allows the solenoid unit U to have a simplified structure and a smaller overall size, while efficiently forming a magnetic path through which magnetic lines of force pass.

[0063] In the above embodiment, the solenoid unit U is surrounded by a resin housing H, and the housing H is joined to the front yoke 60. This allows weight reduction to be achieved while ensuring mechanical strength and forming a magnetic path in a necessary area.

[0064] In addition, in the above embodiment, the solenoid unit U includes a first solenoid unit U1 and a second solenoid unit U2 arranged adjacent to each other and parallel to each other, the shaft 90 includes a first shaft V1 connected to the movable element 70 of the first solenoid unit U1 and a second shaft V2 connected to the movable element 70 of the second solenoid unit U2, and the guide member 100 includes a first guide passage 102 that guides the first shaft V1 so that it can move back and forth, and a second guide passage 103 that guides the second shaft V2 so that it can move back and forth. This makes it possible to selectively operate the first shaft V1 and the second shaft V2 to perform two desired switching operations.

[0065] In addition, in the above embodiment, the first shaft V1 and the second shaft V2 are arranged biased toward each other in the direction of the orthogonal line L1 that is perpendicular to the axis S1 of the first solenoid unit U1 and the axis S2 of the second solenoid unit U2. According to this, in the case of an object to which the engagement grooves G1, G2, etc., into which the first shaft V1 and the second shaft V2 engage, are formed in a nearby area, the first shaft V1 and the second shaft V2 can be adapted to the engagement grooves G1, G2 to ensure the intended function.

[0066] In addition, in the above embodiment, the stator includes a cylindrical inner yoke 30 that accommodates the plunger 70a of the movable element 70 so that it can move back and forth freely, an outer yoke 40 that surrounds the coil 80 arranged around the inner yoke 30, a rear yoke 50 that joins the inner yoke 30 and the outer yoke 40, and a front yoke 60 that joins the guide member 100 and the outer yoke 40, and the outer yoke 40 of the first solenoid unit U1 and the outer yoke 40 of the second solenoid unit U2 form curved plates that include cutout portions 41 that are cut out so that the cross section perpendicular to the axes S1 and S2 is C-shaped, and the respective cutout portions 41, 41 are arranged adjacent to each other and facing each other. This allows the first solenoid unit U1 and the second solenoid unit U2 to be disposed close to each other, thereby enabling the integration of parts and the overall miniaturization to be achieved.

[0067] Furthermore, in the above embodiment, the rear yoke 50 of the first solenoid unit U1 and the rear yoke 50 of the second solenoid unit U2 are a common rear yoke integrally formed as a single member, and the front yoke 60 of the first solenoid unit U1 and the front yoke 60 of the second solenoid unit U2 are a common front yoke integrally formed as a single member. This allows the inner yoke 30 of the first solenoid unit U1 and the inner yoke 30 of the second solenoid unit U2 to be positioned and fixed at predetermined positions relative to each other with high precision using the common rear yoke (rear yoke 50) and the common front yoke (front yoke 60).

[0068] In the above embodiment, the first solenoid unit U1 and the second solenoid unit U2 are surrounded by a resin housing H, and the housing H is joined to a common front yoke (front yoke 60). This makes it possible to achieve weight reduction and ensure mechanical strength while accommodating the first solenoid unit U1 and the second solenoid unit U2, and to form a magnetic path in a necessary area.

[0069] In the above embodiment, the mover 70 includes the plunger 70a and the disk member 70b, but this is not limited to this, and any other form of mover may be used as long as the shaft 90 is connected to the mover with a predetermined play.

[0070] In the above embodiment, the structure for connecting the shaft 90 to the movable member 70 is shown as a configuration in which a slit 72c is provided in the disc member 70b, and the shaft 90 includes a neck portion 91 that is inserted into the slit 72c and a head portion 92 that has an outer diameter larger than that of the neck portion 91, but this is not limited to this, and other types of connecting structures may also be adopted.

[0071] In the above embodiment, the disk member 70b includes a first disk 71 located on the mover 70 side and a second disk 72 located on the shaft 90 side, the second disk 72 including a slit 72c, and the shaft 90 is connected to the second disk 72, but this is not limiting. For example, a configuration may be adopted in which the disk member includes a second disk located on the mover 70 side and a first disk located on the shaft 90 side, the second disk including a slit, the first disk and the permanent magnet including a notch and a hollowed-out portion through which the shaft passes, and the shaft 90 is connected by passing a neck portion through the slit of the second disk.

[0072] In the above embodiment, the disk member 70b of the mover 70 includes the permanent magnet 74, and the magnetic force of the permanent magnet 74 stops and maintains the disk member 70b at the retracted position and the advanced position. However, the present invention is not limited to this. As long as the shaft is connected to the mover with a predetermined play, a configuration may be adopted in which the permanent magnet is eliminated and a spring is used to urge the mover to the retracted position, and the mover and shaft are moved to and maintained at the advanced position by energizing the coil 80.

[0073] In the above embodiment, a configuration is shown in which the shaft 90 is connected to the disc member 70b on an offset axis D (D1, D2) that is offset parallel to the axis S (S1, S2) of the plunger 70a of the movable member 70, but this is not limited to this, and a configuration in which the shaft is connected on the same axis as the plunger may also be adopted.

[0074] In the above embodiment, the solenoid unit U is configured to include a first solenoid unit U1 and a second solenoid unit U2, but this is not limited to this and a configuration including one solenoid unit or three or more solenoid units may also be adopted.

[0075] In the above embodiment, the rear yoke and front yoke of the first solenoid unit U1 and the rear yoke and front yoke of the second solenoid unit U2 are shown as a common rear yoke (rear yoke 50) and a common front yoke (front yoke 60) integrally formed as a single member, but this is not limited to this, and separately formed rear yokes and front yokes may also be used.

[0076] As described above, the electromagnetic actuator of the present invention can simplify the structure and reduce frictional resistance and resistance load without increasing the number of parts, and can reliably link the shaft with the mover to ensure the desired operation. Therefore, it is not only applicable to camshaft switching mechanisms for internal combustion engines, but is also useful as switching mechanisms, drive mechanisms, etc. in other fields. [Explanation of symbols]

[0077] S, S1, S2 axis D,D1,D2 deviation axis L1, L2 orthogonal lines H Housing 10 Housing body 20 Housing cover U Solenoid Unit U1 First solenoid unit U2 Second solenoid unit V1 1st shaft V2 2nd shaft 30 Inner yoke (stator) 33 Annular flange (part of the stator) 33a Annular end face 40 Outer yoke (stator) 41 Notch 50 Rear yoke (common rear yoke, stator) 60 Front yoke (common front yoke, stator) 70 Mover 70a plunger 70a1 end face 70b Disc member 71 First disc 72 Second Disc 72c slit 73 Ring 74 Permanent Magnets 74b Hollowed-out section 75 Contact plate 80 coils 81 Bobbin 90 shaft 91 Neck C1 Gap (first play, play) C2 Gap (second play, play) C3 Gap (play) 92 Head 100 Guide member 101 fitting part 102 First guide passage 103 Second guide passage 104 Cutout 105 End face 106 Annular groove

Claims

1. a solenoid unit including a mover that reciprocates along a predetermined axis, a stator that forms a magnetic path, and an exciting coil; a cylindrical shaft that moves integrally with the mover; a guide member that guides the shaft so that it can reciprocate freely, The shaft is made of a non-magnetic material and is connected to the mover with a predetermined play. Electromagnetic actuator.

2. The movable element includes a cylindrical plunger extending in the axial direction and a disk member fixed to an end of the plunger, the disk member includes a slit extending in a direction perpendicular to the axis; The shaft includes a neck portion that is inserted into the slit, and a head portion that has an outer diameter larger than that of the neck portion.

2. The electromagnetic actuator according to claim 1.

3. The shaft is connected to the disk member on an offset axis that is offset parallel to the axis.

3. The electromagnetic actuator according to claim 2.

4. the disk member includes a first disk, a second disk, a cylindrical ring interposed between the first disk and the second disk, and a permanent magnet sandwiched between the first disk and the second disk inside the ring, the second disk includes the slit, The slit is cut out radially outward on a line perpendicular to the axis.

4. The electromagnetic actuator according to claim 3.

5. the guide member is made of a magnetic material, When the coil is not energized, the movable member is selectively stopped at a retracted position where the disk member is attracted to a part of the stator and at an advanced position where the disk member is attracted to the guide member by a magnetic force exerted by the permanent magnet.

5. The electromagnetic actuator according to claim 4.

6. the disk member includes an abutment plate that abuts against a portion of the stator when in the retracted position, the first disk and the second disk are made of a magnetic material; The contact plate is made of a non-magnetic material.

6. The electromagnetic actuator according to claim 5.

7. When the neck portion of the shaft is inserted into the slit and assembled, the inner wall surface of the ring faces the head portion to prevent the shaft from slipping out.

5. The electromagnetic actuator according to claim 4.

8. The neck portion is inserted into the slit with a first play in the width direction of the slit.

4. The electromagnetic actuator according to claim 3.

9. The neck portion is inserted into the slit with a second play in the direction of the offset axis.

4. The electromagnetic actuator according to claim 3.

10. The permanent magnet includes a hollowed-out portion for receiving the head in a non-contact manner.

5. The electromagnetic actuator according to claim 4.

11. The stator includes a cylindrical inner yoke that accommodates the plunger of the mover so as to be capable of reciprocating motion, an outer yoke that surrounds the coil disposed around the inner yoke, a rear yoke that joins the inner yoke and the outer yoke, and a front yoke that joins the guide member and the outer yoke.

3. The electromagnetic actuator according to claim 2.

12. a resin housing surrounding the solenoid unit; The housing is joined to the front yoke.

12. The electromagnetic actuator according to claim 11.

13. The solenoid unit includes a first solenoid unit and a second solenoid unit arranged adjacent to each other in parallel, the shaft includes a first shaft connected to the movable element of the first solenoid unit and a second shaft connected to the movable element of the second solenoid unit; The guide member includes a first guide passage that guides the first shaft so that it can reciprocate, and a second guide passage that guides the second shaft so that it can reciprocate.

11. The electromagnetic actuator according to claim 3, wherein the electromagnetic actuator is a rotor.

14. the first shaft and the second shaft are biased toward each other in a direction of an orthogonal line perpendicular to the axis of the first solenoid unit and the axis of the second solenoid unit, 14. The electromagnetic actuator according to claim 13.

15. the stator includes a cylindrical inner yoke that accommodates the plunger of the mover so as to be capable of reciprocating motion, an outer yoke that surrounds the coil disposed around the inner yoke, a rear yoke that joins the inner yoke and the outer yoke, and a front yoke that joins the guide member; The outer yoke of the first solenoid unit and the outer yoke of the second solenoid unit are curved plates including notched portions cut out so that a cross section perpendicular to the axis is C-shaped, and the notched portions are arranged adjacent to each other and facing each other.

14. The electromagnetic actuator according to claim 13.

16. the rear yoke of the first solenoid unit and the rear yoke of the second solenoid unit are a common rear yoke integrally formed as a single member, the front yoke of the first solenoid unit and the front yoke of the second solenoid unit are a common front yoke integrally formed as a single member; 16. The electromagnetic actuator according to claim 15.

17. a resin housing that surrounds the first solenoid unit and the second solenoid unit; the housing is joined to the common front yoke; 17. The electromagnetic actuator according to claim 16.

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