Electromagnetic actuator

Abstract

To provide an electromagnetic actuator capable of simplifying a structure without increasing the number of components, reducing resistance force (resistance load) due to viscosity resistance of lubricating oil in an application object, and ensuring desired operation by surely interlocking a shaft with a movable element.SOLUTION: A solenoid device includes a solenoid unit U including a mover 70 that reciprocates along an axis S, a stator 30,40,50,60 that forms a magnetic path, and an excitation coil 80, a shaft 90 that moves integrally with the mover, and a guide member 100 including a guide passage 102,104 that guides the shaft so as to be able to reciprocate, and the guide member 100 includes an adjacent passage 103,105 that is adjacent to and communicates with the guide passage 102,104 and leads to the outside.SELECTED DRAWING: Figure 2

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 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 has a guide passage that guides the tappet unit so that it can reciprocate freely (see, for example, Patent Document 1).

[0003] In this electromagnetic drive device, the tappet unit is slidably inserted into a guide passage formed in the housing, with the entire outer circumferential surface of the tappet unit in close contact with the inner circumferential surface of the guide passage. If this electromagnetic drive device is applied to, for example, a camshaft switching mechanism that switches cams by displacing the camshaft of an engine in the axial direction, the tappet unit will operate in a space exposed to an atmosphere of lubricating oil.

[0004] When the tappet unit repeatedly moves forward and backward, if lubricating oil adheres to the area around the tappet unit, the operation of the tappet unit becomes smoother. However, when the viscosity of the lubricating oil is high, for example when the engine is cold, if the lubricating oil enters the sliding interface and remains in that area or inside the housing, the viscous resistance of the lubricating oil will act on the operation of the tappet unit, resulting in poor responsiveness and the risk of malfunction.

[0005] In the electromagnetic drive device, the tappet unit is attracted to the permanent magnet of the armature by magnetic force and moves integrally with the armature. Therefore, at least the area of ​​the tappet unit that engages with the armature must be made of a magnetic material. If the housing is made of a magnetic material, a magnetic path is formed between the tappet unit and the housing, generating a magnetic force that attracts the tappet unit to the housing. As a result, there is a risk of increased resistance due to frictional resistance when the tappet unit moves. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] 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 its object is to provide an electromagnetic actuator that can simplify the structure without increasing the number of parts, reduce resistance (resistance load) due to viscous resistance of lubricating oil in the object to which it is applied, and can reliably link the shaft with the mover to ensure the desired operation. [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 shaft that moves integrally with the mover; and a guide member that includes a guide passage that guides the shaft so that it can reciprocate freely, and the guide member includes an adjacent passage that is adjacent to and communicates with the guide passage and leads to the outside.

[0009] In the electromagnetic actuator, the shaft may be formed in a cylindrical shape, the guide passage may be a passage defined by an inner wall surface that is divided in the circumferential direction of a cylindrical surface with which the shaft slidably contacts, and the adjacent passage may be a groove-like passage that extends parallel to and communicates with the guide passage in the region where the cylindrical surface is divided.

[0010] In the electromagnetic actuator, the adjacent passages may include a plurality of groove-like passages arranged radially around a center line of the cylindrical surface, the cylindrical surface being divided into a plurality of sections in the circumferential direction.

[0011] In the electromagnetic actuator, the adjacent passage may be formed in a region that is apart from the guide passage by a predetermined central angle with a first straight line that is perpendicular to the center line of the cylindrical surface as the center.

[0012] In the electromagnetic actuator, the adjacent passage may be formed in a region outside a predetermined central angle with respect to the guide passage, with a first line perpendicular to the center line of the cylindrical surface as the center, and excluding a region facing in the direction of a second line perpendicular to the center line and the first line.

[0013] In the electromagnetic actuator, the adjacent passage may be formed to include an inner wall surface that is curved concavely in a region farthest from the guide passage.

[0014] In the electromagnetic actuator, the adjacent passage may be configured to include an inner wall surface that curves convexly as it approaches the guide passage, in addition to the inner wall surface that curves concavely.

[0015] In the electromagnetic actuator, the guide member may have a configuration including a lightening portion in an area away from the guide passage and the adjacent passage.

[0016] In the electromagnetic actuator, the hollowed portion may be formed as a through hole communicating with the outside.

[0017] In the electromagnetic actuator, the shaft may be made of a non-magnetic material and may be connected to the mover with a predetermined play therebetween.

[0018] In the above-described 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 and incorporating a permanent magnet, and the shaft may be connected to the disk member on an offset axis offset parallel to the axis.

[0019] 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.

[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, as guide passages, 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 electromagnetic actuator, the first shaft and the second shaft may be 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 a portion 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 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] The electromagnetic actuator having the above configuration can simplify the structure and reduce the resistance force (resistance load) due to the viscous resistance of the lubricating oil in the object to which it is applied, without increasing the number of parts, and can reliably link the shaft with the movable element to ensure 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] FIG. 2 is an end view of the electromagnetic actuator according to the embodiment, viewed from the guide member side. [Figure 6] 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 7] 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 8] 2 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 9] 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 10] 1 is an external perspective view showing a mover and a shaft included in an electromagnetic actuator according to an embodiment; [Figure 11] FIG. 11 is an exploded perspective view of the mover and the shaft shown in FIG. [Figure 12] 11 is an enlarged cross-sectional view of the mover and shaft shown in FIG. 10, taken along a plane including the offset axis of the shaft, and partially enlarged. FIG. [Figure 13] 11 is an enlarged cross-sectional view of the mover and shaft shown in FIG. 10, taken along a plane including the axis of the plunger of the mover and the offset axis of the shaft, and partially enlarged. FIG. [Figure 14] 1 is a cross-sectional view of an electromagnetic actuator according to one embodiment, taken along a plane perpendicular to an axis, of a space facing an inner end face of a guide member joined to a front yoke. FIG. [Figure 15]3 is a partial cross-sectional view of an electromagnetic actuator according to one embodiment, taken along a plane passing through an adjacent passage adjacent to a first guide passage. FIG. [Figure 16] FIG. 2 is an external perspective view showing a guide member included in the electromagnetic actuator according to the embodiment. [Figure 17] 17 is a perspective cross-sectional view of the guide member shown in FIG. 16, taken along a plane passing through the center line of a cylindrical surface that defines a first guide passage and the center line of a cylindrical surface that defines a second guide passage. [Figure 18] 17 is an end view of the guide member shown in FIG. 16 as viewed from the direction of the end face located inside the electromagnetic actuator. FIG. [Figure 19] 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 20] 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 21] 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. 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 freely.

[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, 4, 6, and 7, 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 7 and 9, 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 6 to 9, 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 8, 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 X 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 X, 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, 7, and 9, 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 7, 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. 10 to 13, 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, the slit 72c extends on an orthogonal line 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-described configuration, the neck portion 91 of the shaft 90 is inserted into the slit 72c of the second disk 72, the ring 73 is stacked on the second disk 72, a permanent magnet 74 is placed inside the ring 73, the first disk 71 is joined and stacked on 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 Figure 13, 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. 7. 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. 11 to 13, 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 FIG. 12, the neck portion 91 of the shaft 90 is inserted into the slit 72c with a gap C1 (C1 / 2+C1 / 2) as play in the width direction of the slit 72c, and as shown in FIG. 13, the neck portion 91 of the shaft 90 is inserted into the slit 72c with a gap C2 as play in the length direction of the slit 72c and a gap C3 as play in the direction of the offset axis D (D1, D2). 12, when the shaft 90 is inserted into the slit 72c and connected to the mover 70 with a predetermined 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. Furthermore, as shown in FIG. 13, when the neck 91 of the shaft 90 is inserted into the slit 72c and assembled, the inner wall surface of the ring 73 faces the head 92 to prevent the shaft 90 from falling out.

[0045] In this way, by connecting the shaft 90 to the movable member 70 with a predetermined play (gaps C1, C2), 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 104 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 C3), 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 19 to 21) 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 and 14 to 18, is provided with a fitting portion 101, a first guide passage 102, a first adjacent passage 103 as an adjacent passage adjacent to the first guide passage 102, a second guide passage 104, a second adjacent passage 105 as an adjacent passage adjacent to the second guide passage 104, two lightening portions 106, an end face 107, and an annular groove 108. 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.

[0047] 18, the first guide passage 102 extends in the direction of the center line CL1 of the cylindrical surface Cf1 with which the shaft 90 can slidably come into contact, and is formed as a passage defined by a plurality of inner wall surfaces 102a formed by dividing the cylindrical surface Cf1 into a plurality of parts in the circumferential direction, and guides the shaft 90 serving as the first shaft V1 so that it slides and reciprocates. Here, the center line CL1 coincides with the offset axis D1 when the shaft 90 serving as the first shaft V1 is inserted into the first guide passage 102. The first adjacent passage 103 is formed adjacent to and in communication with the first guide passage 102 and also in communication with the outside of the electromagnetic actuator. Specifically, the first adjacent passage 103 is formed as a plurality (four in this case) of groove-like passages that are arranged radially around the center line CL1 in a region where the cylindrical surface Cf1 is divided circumferentially on a plane perpendicular to the center line CL1 and that extend parallel to and communicate with the first guide passage 102.

[0048] That is, the first adjacent passage 103 is formed in an area outside a predetermined central angle α with a first straight line L1 perpendicular to the center line CL1 as the center and excluding an area facing the direction of a second straight line L2 perpendicular to the center line CL1 and the first straight line L1. The central angle α is, for example, about 80 degrees and can be appropriately selected in the range of 60 degrees to 90 degrees. In addition, the first adjacent passage 103 is formed to include an inner wall surface 103a that is concavely curved in the region farthest from the first guide passage 102 (cylindrical surface Cf1), and an inner wall surface 103b that is convexly curved as it approaches the first guide passage 102 (cylindrical surface Cf1).

[0049] 18, the second guide passage 104 extends in the direction of the center line CL2 of the cylindrical surface Cf2 with which the shaft 90 can slidably come into contact, and is formed as a passage defined by a plurality of inner wall surfaces 104a formed by dividing the cylindrical surface Cf2 into a plurality of parts in the circumferential direction, and guides the shaft 90 serving as the second shaft V2 so that it slides and reciprocates. Here, the center line CL2 coincides with the offset axis D2 when the shaft 90 serving as the second shaft V2 is inserted into the second guide passage 104. The second adjacent passage 105 is formed adjacent to and in communication with the second guide passage 104 and also in communication with the outside of the electromagnetic actuator. Specifically, the second adjacent passage 105 is formed as a plurality (four in this case) of groove-like passages that are arranged radially around the center line CL2 in a region where the cylindrical surface Cf2 is divided circumferentially in a plane perpendicular to the center line CL2 and that extend parallel to and communicate with the second guide passage 104.

[0050] That is, the second adjacent passage 105 is formed in an area outside a predetermined central angle α with a first straight line L1 perpendicular to the center line CL2 as the center and excluding an area facing the direction of a second straight line L2 perpendicular to the center line CL1 and the first straight line L1. The central angle α is, for example, about 80 degrees and can be appropriately selected in the range of 60 degrees to 90 degrees. In addition, the second adjacent passage 105 is formed to include an inner wall surface 105a that is concavely curved in the region farthest from the second guide passage 104 (cylindrical surface Cf2), and an inner wall surface 105b that is convexly curved as it approaches the second guide passage 104 (cylindrical surface Cf2).

[0051] In the above embodiment, since a common shaft 90 is used as the first shaft V1 and the second shaft V2, the first guide passage 102 and the second guide passage 104 are formed to have the same shape and dimensions as each other, and the first adjacent passage 103 and the second adjacent passage 105 are also formed to have the same shape and dimensions as each other. The first adjacent passage 103 and the second adjacent passage 105 function as passages for discharging lubricating oil from an object to which they are applied when the lubricating oil enters the inside of the electromagnetic actuator.

[0052] The two lightening portions 106 are formed as through-holes that extend parallel to the center lines CL1 and CL2 in a direction perpendicular to the direction in which the first guide passage 102 and the second guide passage 104 are arranged, in areas away from the first guide passage 102 and the first adjacent passage 103 and the second guide passage 104 and the second adjacent passage 105. The lightening portions 106 contribute to reducing the overall weight, and also function as passages for discharging lubricating oil from an object to which the electromagnetic actuator is applied when the lubricating oil enters the inside of the electromagnetic actuator. The end face 107 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, thereby positioning the disc member 70b at an advanced position where the disc member 70b is attracted to the guide member 100. The annular groove 108 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.

[0053] Next, the operation of the electromagnetic actuator having the above configuration when it is applied to a camshaft switching mechanism of an internal combustion engine will be described with reference to Figures 19 to 21. Here, the electromagnetic actuator according to the above embodiment is arranged so that the direction of the first straight line L1 is parallel to the direction of the axis A of the camshaft CS.

[0054] That is, since a driving load acts on the first shaft V1 and the second shaft V2 in the direction of the axis A, by orienting the first straight line L1 in the direction of the axis A, the inner wall surface 102a of the first guide passage 102 supports the first shaft V1 in the radial direction, and the inner wall surface 104a of the second guide passage 104 supports the second shaft V2 in the radial direction.

[0055] 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. 19. 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.

[0056] 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 Figure 20. 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.

[0057] 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.

[0058] 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 21. 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.

[0059] 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.

[0060] As described above, when the shaft 90 serving as the first shaft V1 and the second shaft V2 reciprocates, the shaft 90 is exposed to an atmosphere of lubricating oil that lubricates the camshaft CS. Even if the lubricating oil enters the sliding interface between the first guide passage 102 and the second guide passage 104 of the shaft 90 or into the inside of the electromagnetic actuator, it is efficiently discharged to the outside of the electromagnetic actuator (i.e., the inside of the internal combustion engine, which forms the lubricating oil atmosphere) via the first adjacent passage 103 and the second adjacent passage 105. The operation of the electromagnetic actuator is not limited to the above method, and other operation methods may be applied.

[0061] The electromagnetic actuator according to the above embodiment can simplify the structure and reduce the resistance force (resistance load) due to the viscous resistance of the lubricating oil in the object to which it is applied, without increasing the number of parts, and can reliably link the shaft 90 to the movable element to ensure the desired operation.

[0062] As described above, the electromagnetic actuator of the present invention comprises a solenoid unit U including a mover 70 that reciprocates along a predetermined 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 shaft 90 that moves integrally with the mover 70, and a guide member 100 that includes guide passages (first guide passage 102, second guide passage 104) that guide the shaft 90 so that it can reciprocate freely, and the guide member 100 includes adjacent passages (first adjacent passage 103, second adjacent passage 105) that are adjacent to and communicate with the guide passages (first guide passage 102, second guide passage 104) and lead to the outside. According to this, when the electromagnetic actuator is used as a camshaft switching mechanism in a space exposed to a lubricating oil atmosphere, even if the lubricating oil gets into the sliding interface of the guide passage of the shaft or into the inside of the electromagnetic actuator, it can be efficiently discharged to the outside of the electromagnetic actuator (i.e., the inside of the internal combustion engine which forms the lubricating oil atmosphere) through an adjacent passage. Therefore, even when the viscosity of the lubricating oil is high, particularly when the engine is cold, the resistance force (resistance load) due to the viscous resistance of the lubricating oil can be reduced, and the shaft can be reliably linked to the moving element to ensure the desired operation.

[0063] Furthermore, in the above embodiment, the shaft 90 is formed in a cylindrical shape, and the guide passages (first guide passage 102, second guide passage 104) are passages defined by inner wall surfaces 102a, 104a formed by dividing cylindrical surfaces Cf1, Cf2 in the circumferential direction, with which the shaft 90 can slide freely, and the adjacent passages 103, 105 are groove-like passages that extend parallel to and communicate with the guide passages in the regions where the cylindrical surfaces Cf1, Cf2 are divided. This allows the structure to be consolidated, while providing an adjacent passage adjacent to and communicating with the guide passage.

[0064] In addition, in the above embodiment, the adjacent passages (first adjacent passage 103, second adjacent passage 105) include a plurality of groove-like passages that are arranged radially around the center lines CL1, CL2 of the cylindrical surfaces Cf1, Cf2, with the cylindrical surfaces Cf1, Cf2 divided into a plurality of parts in the circumferential direction. This makes the conditions for exposure to lubricating oil uniform around the shaft 90, allowing the lubricating oil to be efficiently discharged and the shaft 90 to operate more smoothly.

[0065] In addition, in the above embodiment, the adjacent passages (first adjacent passage 103, second adjacent passage 105) are formed relative to the guide passages (first guide passage 102, second guide passage 104) in an area outside a predetermined central angle α with the first straight line L1, which is perpendicular to the center lines CL1, CL2 of the cylindrical surfaces Cf1, Cf2, as the center, and excluding an area facing the direction of the second straight line L2, which is perpendicular to the center lines CL1, CL2 and the first straight line L1. As a result, even if the object to which the drive load is applied is in the direction of the first straight line L1 (i.e., the radial direction of the shaft 90), the shaft 90 is reliably supported in the direction in which the drive load is applied and in a direction perpendicular to the direction in which the drive load is applied, allowing the shaft 90 to operate smoothly without any rattle.

[0066] In addition, in the above embodiment, the adjacent passages (first adjacent passage 103, second adjacent passage 105) are formed to include inner wall surfaces 103a, 105a that are concavely curved in the region farthest from the guide passages (first guide passage 102, second guide passage 104). This allows lubricating oil that has entered the interior to be smoothly discharged along the inner wall surfaces 103a and 105a.

[0067] In addition, in the above embodiment, the adjacent passages (first adjacent passage 103, second adjacent passage 105) are formed to include inner wall surfaces 103b, 105b that curve convexly as they approach the guide passages (first guide passage 102, second guide passage 104). This allows lubricating oil that has entered the guide passage to be smoothly discharged toward the adjacent passage, and if the viscosity of the lubricating oil is low, the lubricating oil can be actively guided into the guide passage to obtain a lubricating effect at the sliding interface.

[0068] Furthermore, in the above embodiment, the guide member 100 includes a lightening portion 106 in an area away from the guide passage and adjacent passages, thereby achieving a reduction in the weight of the guide member 100, and further, since the lightening portion 106 is formed as a through hole communicating with the outside, the through hole of the lightening portion 106 can also be used to smoothly discharge lubricating oil that has penetrated up to the internal end face 107.

[0069] In the above embodiment, 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, and since the shaft 90 is connected to the mover 70 with a predetermined amount of play, when the shaft 90 is guided in the guide passages (first guide passage 102, second guide passage 104), it is possible to prevent galling and the like and operate smoothly, and the shaft 90 can be reliably linked to the mover 70 to ensure the desired function.

[0070] In addition, in the above embodiment, the movable element 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 and incorporating a permanent magnet 74, and 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.

[0071] Furthermore, in the above embodiment, the guide member 100 is formed from a magnetic material, and when the coil 80 is not energized, 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 due to the magnetic force exerted by the permanent magnet 74. 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.

[0072] 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 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, as guide passages, a first guide passage 102 that guides the first shaft V1 so that it can move back and forth, and a second guide passage 104 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.

[0073] 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 X 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.

[0074] In addition, in the above embodiment, the stator includes a cylindrical inner yoke 30 that accommodates a portion of the movable element 70 (plunger 70a) so that it can move back and forth, 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 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.

[0075] 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).

[0076] 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.

[0077] In the above embodiment, the guide passages are shown as guide passages (first guide passage 102, second guide passage 104) in which the cylindrical surfaces Cf1, Cf2 are divided into multiple parts in the circumferential direction and include multiple groove-like passages arranged radially around the center lines CL1, CL2 of the cylindrical surfaces Cf1, Cf2, but this is not limited to this, and a configuration in which the cylindrical surfaces Cf1, Cf2 are divided into only one part in the circumferential direction and include one groove-like passage as an adjacent passage may also be adopted.

[0078] In the above embodiment, the adjacent passage that is adjacent to the guide passage and communicates with the outside is shown to be a groove-like passage that extends parallel to and communicates with the guide passages (first guide passage 102, second guide passage 104), but this is not limited to this, and adjacent passages of other shapes may be used as long as they are adjacent to the guide passage and communicate with the outside. For example, a cylindrical guide passage formed in a guide member may have a spiral groove formed on its inner peripheral surface to serve as an adjacent passage.

[0079] 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.

[0080] 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.

[0081] 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.

[0082] 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.

[0083] As described above, the electromagnetic actuator of the present invention can simplify the structure and reduce the resistance force (resistance load) due to the viscous resistance of the lubricating oil in the object to which it is applied, without increasing the number of parts, and can reliably link the shaft to the mover to ensure the desired operation. Therefore, it is not only applicable to the camshaft switching mechanism of an internal combustion engine, but is also useful as a switching mechanism or drive mechanism in other fields. [Explanation of symbols]

[0084] S, S1, S2 axis D,D1,D2 deviation axis L1,L2,X 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 92 Head C1, C2, C3 gap (play) 100 Guide member 101 fitting part 102 First guide passage Cf1 cylindrical surface CL1 center line α central angle 102a Inner wall 103 First adjacent passage 103a Concavely curved inner wall surface 103b Convexly curved inner wall surface 104 Second Guide Passage Cf2 cylindrical surface CL2 center line 104a Inner wall 105 Second adjacent passage 105a Concavely curved inner wall surface 105b Convexly curved inner wall surface 106 Cutout 107 End face 108 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 shaft that moves integrally with the mover; a guide member including a guide passage that guides the shaft so that it can reciprocate; The guide member includes an adjacent passage that is adjacent to and communicates with the guide passage and leads to the outside. Electromagnetic actuator.

2. The shaft is formed in a cylindrical shape, the guide passage is a passage defined by an inner wall surface that is a cylindrical surface with which the shaft can slidably contact and that is divided in the circumferential direction, the adjacent passage forms a groove-like passage extending parallel to and communicating with the guide passage in the region where the cylindrical surface is divided; 2. The electromagnetic actuator according to claim 1.

3. the adjacent passages include a plurality of groove-like passages that are radially arranged around a center line of the cylindrical surface by dividing the cylindrical surface into a plurality of sections in the circumferential direction, 3. The electromagnetic actuator according to claim 2.

4. the adjacent passage is formed in a region that is apart from the guide passage by a predetermined central angle with a first straight line that is perpendicular to the center line of the cylindrical surface as a center.

3. The electromagnetic actuator according to claim 2.

5. the adjacent passage is formed with respect to the guide passage in a region outside a predetermined central angle with a first straight line perpendicular to the center line of the cylindrical surface as a center and excluding a region facing in a direction of a second straight line perpendicular to the center line and the first straight line.

3. The electromagnetic actuator according to claim 2.

6. the adjacent passage is formed to include an inner wall surface that is concavely curved in a region farthest from the guide passage; 3. The electromagnetic actuator according to claim 2.

7. The adjacent passage is formed to include an inner wall surface that curves convexly as it approaches the guide passage.

7. The electromagnetic actuator according to claim 6, wherein:

8. The guide member includes a lightening portion in a region away from the guide passage and the adjacent passage.

2. The electromagnetic actuator according to claim 1.

9. The hollowed portion is formed as a through hole communicating with the outside.

9. The electromagnetic actuator according to claim 8.

10. The shaft is made of a non-magnetic material and is connected to the mover with a predetermined play.

2. The electromagnetic actuator according to claim 1.

11. The mover includes a cylindrical plunger extending in the direction of the axis, and a disk member fixed to an end of the plunger and incorporating a permanent magnet, The shaft is connected to the disk member on an offset axis that is offset parallel to the axis.

11. The electromagnetic actuator according to claim 10.

12. 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.

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, as the guide passage, a first guide passage that guides the first shaft so as to be reciprocatable, and a second guide passage that guides the second shaft so as to be reciprocatable.

13. The electromagnetic actuator according to claim 1, wherein the electromagnetic actuator comprises:

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 a portion 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.

15. The electromagnetic actuator according to claim 14.

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.

Images