JP7298143B2 - electromagnetic solenoid - Google Patents

Description

The present invention relates to an electromagnetic solenoid that linearly actuates a mover by an electromagnetic force acting from a stator when an excitation coil is energized.

As an electromagnetic solenoid having the above configuration, in Patent Documents 1 and 2, a stator is provided at a position surrounding a shaft and a mover that fixes the shaft, and as the stator, a first stator core is provided on the front side in the moving direction of the shaft. A technique is described in which the second stator core is provided on the rear side. In the techniques described in Patent Literatures 1 and 2, the first stator core and the second stator core are arranged apart from each other, and are axially sandwiched between the first stator core and the second stator core. A tubular collar (sleeve in patent document 2) is provided. The first stator core and the second stator core are configured not to move relative to each other in the axial direction and the radial direction due to the interposition of the collar.

JP 2014-27202 A U.S. Patent Application Publication No. 2011/0285484

As described above, an electromagnetic solenoid may use a cylindrical collar to maintain the coaxiality of two stator cores that apply electromagnetic force to the mover. However, since the stator configured in this manner has an increased number of parts, there is a possibility that the first stator core and the second stator core may be misaligned due to the influence of their respective tolerances. Therefore, it may be necessary to set the outer diameters of the mover and the shaft in consideration of such tolerances.

Therefore, it is conceivable to configure the stator as one member by integrating the first stator core and the second stator core. In this way, since the stator is a single member, the axis can be set with high accuracy. However, in that case, it is difficult to place a bush as a bearing in the middle of the inner circumference of the stator in the axial direction. It is assembled on the opposite rear end side. In the electromagnetic solenoid configured in this way, the movable element is supported by the entire bush in the axial direction at the initial position (non-operating position) where the movable element is at the rearmost end. However, when the mover protrudes together with the shaft, the engagement length of the bush with respect to the mover in the axial direction becomes short. Therefore, the mover tends to tilt obliquely with respect to the axial direction. In this case, the mover approaches the stator, and the lateral force of the electromagnetic force is likely to act on the mover. As a result, the operating efficiency of the electromagnetic solenoid is lowered and the hysteresis of the attraction force is deteriorated. In the worst case, the stator and the mover may come into contact with each other, causing a magnetic short circuit. In order to suppress such inclination of the mover, it is conceivable to reduce the clearance between the mover and the bush. However, in this case, lubricating oil may not spread between the outer peripheral surface of the mover and the bush, and the oil film may run out, resulting in deterioration of the wear resistance of the mover and the bush. Thus, the electromagnetic solenoid has room for improvement in constructing the stator with a single member.

In view of the above situation, there is a demand for an electromagnetic solenoid in which a mover can stably perform linear operation with respect to a stator having a simple structure.

An electromagnetic solenoid according to the present invention is characterized by: an exciting coil that generates magnetic flux when energized; a stator serving as a path; a cylindrical mover made of a magnetic material, which is housed in an inner space of the stator so as to be movable along the axis by electromagnetic force generated by the magnetic flux; a shaft that is provided on the mover coaxially with the axis and that projects integrally with the mover to one side in the axial direction of the stator and retracts to the other side in the axial direction of the stator; , fixed to the inner peripheral surface of the stator from the other end in the axial direction of the stator toward the middle portion in the axial direction of the stator, and the outer peripheral surface of the mover a supporting bush, wherein the end surface of the mover on the one side in the axial direction of the stator, of the inner peripheral surface of the stator, protrudes from the intermediate portion. In the range, a gap is formed between the inner peripheral surface of the stator and the outer peripheral surface of the mover by having an inner diameter larger than the inner diameter of the bush, and the gap is formed in the axial direction of the stator. The point is that the tapered portion is provided so that the inner diameter increases toward one side.

According to this configuration, the inner peripheral surface of the stator is provided with a tapered portion formed so that the inner diameter increases as the mover moves toward one side in the axial direction of the stator. Even if the mover is tilted with respect to the axis when it protrudes to the side, it is possible to secure a predetermined distance between the outer peripheral surface of the mover and the inner peripheral surface of the stator without bringing the outer peripheral surface of the mover too close to the inner peripheral surface of the stator. . As a result, it is possible to prevent the generation of lateral force due to the electromagnetic force on the mover, and to allow the electromagnetic force from the excitation coil to effectively act on the mover. Also, magnetic short-circuit due to contact between the mover and the stator can be prevented. As a result, it is possible to realize smooth operation of the mover, and to suppress a decrease in operating efficiency of the electromagnetic solenoid.

In addition, by providing a tapered portion on the inner peripheral surface of the stator, there is no need to reduce the clearance between the mover and the bush, so it is possible to reliably secure a clearance that allows oil lubrication between the two. can. As a result, it is possible to prevent the oil film from running out on the outer peripheral surface of the mover, thereby suppressing deterioration in wear resistance of the mover and the bush.

Another characteristic configuration is that when the mover is inclined with respect to the axis of the stator as the mover moves to the one side in the axial direction of the stator, the tapered portion It is formed with a predetermined inclination angle with respect to the axial center of the stator so that the distance from the outer peripheral surface of the mover is constant.

According to this configuration, the tapered portion is formed to have a predetermined inclination angle with respect to the axis of the stator so that the distance from the outer peripheral surface of the mover is constant. As a result, the distance between the outer surface of the mover and the inner peripheral surface of the stator is stably maintained even if the mover is tilted with respect to the axis. As a result, the electromagnetic force acting on the mover can be kept substantially constant regardless of the amount of protrusion of the mover when the mover protrudes.

FIG. 4B is a cross-sectional view of an electromagnetic solenoid with the plunger in a non-actuated position; FIG. 4 is a cross-sectional view of an electromagnetic solenoid with a plunger in an actuated state; 3 is an enlarged cross-sectional view of a main part of an electromagnetic solenoid; FIG.

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described below with reference to the drawings.

[Basic configuration]
As shown in FIGS. 1 and 2, the electromagnetic solenoid 100 includes an exciting coil A that generates magnetic flux when energized, a yoke portion B (an example of a stator) that serves as a magnetic path for the magnetic flux, and the exciting coil A and the yoke portion. and a housing C made of a resin material 8 integrated with B. The electromagnetic solenoid 100 includes a plunger 11 (an example of a mover) and a shaft 12 supported by the plunger 11 in an internal space inside the yoke portion B. As shown in FIG. The plunger 11 is accommodated in the inner space of the yoke portion B so as to be movable along the axis X of the yoke portion B by electromagnetic force generated by the magnetic flux.

In the electromagnetic solenoid 100, the plunger 11 is formed in a columnar shape and is accommodated in the inner space of the yoke portion B so that the axis of the plunger coincides with the axis X. As shown in FIG. A shaft-shaped shaft 12 is fitted and connected to the fitting hole 11a of the plunger 11 so as to be coaxial with the plunger axis. As a result, the plunger 11 and the shaft 12 are arranged coaxially with the axis X.

FIG. 1 shows an electromagnetic solenoid 100 that operates a spool S of a valve opening/closing timing control device (not shown) that hydraulically controls opening/closing timing (valve timing) of intake valves and exhaust valves of a vehicle engine. .

The spool S is biased by a spring (not shown) in the protruding direction (leftward in the figure). The spool S is arranged coaxially with the axis X, and the projecting end of the shaft 12 is brought into contact with the operated surface of the projecting end. As a result, when the electromagnetic solenoid 100 is not operating (the excitation coil A is not energized), the pressing force from the spool S moves the plunger 11 to the non-operating position shown in FIG. moving end).

On the other hand, when the electromagnetic solenoid 100 is actuated (energized to the exciting coil A), as shown in FIG. The shaft 12 protrudes by the amount determined. As a result, the spool S is operated to the target position, and the valve opening/closing timing control device controls the operating oil to set the opening/closing timing of the valve.

In the following description, among the electromagnetic solenoids 100, when the electromagnetic solenoid 100 is actuated, the downstream side (one example) surface (right side in FIGS. 1 and 2) of the plunger 11 in the operation direction (right side in FIGS. surface) is referred to as the front surface, and the surface on the opposite side and upstream in the operating direction (an example of the other side) is referred to as the rear surface.

[Details of the electromagnetic solenoid]
The excitation coil A is composed of a coil 2 in which a wire rod made of a good conductor such as a copper alloy is wound around a bobbin 1 made of non-magnetic and insulating resin. A wire constituting the coil 2 is electrically connected to a terminal 3 inside a connector portion Ca formed integrally with the housing C. As shown in FIG. The exciting coil A is covered on the front side and the outer peripheral side by a case 9 made of a magnetic material such as iron. A plate 10 made of a magnetic material such as iron and having an opening in the center is arranged on the outer peripheral side of the rear end of the plunger 11 . The exciting coil A is housed in an internal space surrounded by the yoke portion B, the case 9 and the plate 10 .

As shown in FIG. 1, the yoke portion B has a cylindrical shape made of a magnetic material such as iron, and is arranged coaxially with the axis X in the space on the inner peripheral side of the cylindrical cylinder of the bobbin 1. . The yoke portion B has a constricted portion 14, which is a depression facing radially inward, formed on the entire circumference of the outer peripheral surface at the central portion in the direction of the axial center X. As shown in FIG. A thin portion 15 (an example of a middle portion) is a portion of the constricted portion 14 that has the smallest outer diameter, that is, a portion of the yoke portion B that is the thinnest in the radial direction. The constricted portion 14 is provided to guide the magnetic flux generated by energizing the coil 2 to the plunger 11 .

Here, in the yoke portion B, with the thin portion 15 as a reference in the direction along the axis X, the front side of the thin portion 15 is defined as the first yoke 5, and the rear side of the thin portion 15 is defined as the second yoke. Define as 6.

As shown in FIG. 1, the first yoke 5 has a tubular first tubular portion 5a centered on the axis X and a side wall portion 5b arranged on the front side of the electromagnetic solenoid 100. An inner peripheral surface 5S centered on the axis X is formed on the first tubular portion 5a. The second yoke 6 has a cylindrical second cylindrical portion 6a centered on the axis X, and an inner peripheral surface 6S centered on the axis X is formed on the second cylindrical portion 6a. .

Inside the yoke portion B in the radial direction, an internal space having a circular cross-sectional shape centering on the axis X is formed. A ring-shaped non-magnetic bushing 7 is fitted in the inner peripheral surface 6S of the second tubular portion 6a. The bush 7 constitutes a second bearing E, which will be described later, and is arranged in a region on the rear surface side of the second tubular portion 6a.

The plunger 11 has a cylindrical shape as described above, and has a front end face 11f formed at the end on the side closer to the front face of the housing C in the direction along the axis X, and a rear end face 11r formed at the other end. ing.

A fitting hole 11a is formed in the plunger 11 coaxially with the plunger axis from the front end face 11f to the rear end face 11r. A shaft 12 is fixed to the fitting hole 11a by a method such as press-fitting or adhesion. As a result, the shaft 12 protrudes toward the front side in the axis X direction integrally with the plunger 11 and retracts toward the rear side in the axis X direction.

When the electromagnetic solenoid 100 is in a non-operating state (a state in which the excitation coil A is not energized), the front end face 11f of the plunger 11 is aligned with the thin portion 15 as shown in FIG. When the electromagnetic solenoid 100 is activated (exciting coil A is energized), the shaft 12 integrally with the plunger 11 protrudes toward the front side in the axis X direction. After that, when the electromagnetic solenoid 100 is deactivated, the shaft 12 is retracted to the rear surface side in the axis X direction integrally with the plunger 11 .

[Bearing structure]
As shown in FIGS. 1 and 2, the electromagnetic solenoid 100 includes a first bearing D that supports the protruding end of the shaft 12 so as to be slidable in the direction along the axis X. is slidably supported in the direction along the axis X. As a result, the plunger 11 and the shaft 12 are integrally guided along the axis X when the electromagnetic solenoid 100 is activated.

A side wall portion 5b on the front side of the first yoke 5 is provided with a through hole 5c through which the shaft 12 passes. The first bearing D is composed of a bearing body 16 that is press-fitted and held in the through hole 5c of the first yoke 5 on the front side of the housing C. As shown in FIG.

The bearing body 16 is arranged at a position to be fitted on the outer end side of the shaft 12, and is made of a ring-shaped material with high wear resistance.

A second bearing E is formed by a bush 7 . The bush 7 is coaxial with the axis X on the inner peripheral surface 6S of the second yoke 6 from the rear end 6b of the yoke part B in the axis X direction toward the thin part 15 of the yoke part B in the axis X direction. It is arranged to be fixed so as to form a core, and supports the outer peripheral surface 11s of the plunger 11 . A portion of the inner peripheral surface 6S of the second yoke 6 to which the bush 7 is fixed is enlarged in diameter. Specifically, as shown in FIGS. 1 and 2, the bush 7 is arranged in a region from the end 6b of the yoke portion B to the narrowed portion 14. As shown in FIGS. As a result, movement of the plunger 11 along the axial center X is allowed while the displacement of the plunger 11 in the direction away from the axial center X is restricted. The inner diameter of the bush 7 is slightly smaller than the inner diameter of the inner peripheral surface 6S of the constricted portion 14 (see FIG. 3). A gap is created between them.

Since the bush 7 of the second bearing E is arranged on the rear surface side of the second yoke 6 , as the plunger 11 moves in the projecting direction (front side), the axial center X of the bush 7 moves relative to the plunger 11 . Directional overhang is reduced. Therefore, the plunger 11 tends to tilt with respect to the axial center X direction. When the plunger 11 is tilted with respect to the axial center X direction, the corner 11c where the outer peripheral surface 11s of the plunger 11 and the front end surface 11f intersect approaches the inner peripheral surface 5S of the first yoke 5 of the yoke portion B. The lateral force of the electromagnetic force by the excitation coil A is likely to act on 11 . As a result, the operating efficiency of the electromagnetic solenoid 100 is lowered and the hysteresis of the attraction force is deteriorated. In the worst case, the yoke portion B and the plunger 11 may come into contact with each other, causing a magnetic short circuit.

Therefore, in the present embodiment, in the range where the front side end face 11f of the plunger 11 operates on the front side of the thin portion 15 of the inner peripheral surface 5S, the inner peripheral surface 5S moves toward the front side (the right side in FIGS. 1 and 2). A tapered portion 5Sa formed so as to increase the inner diameter of the peripheral surface 5S is provided.

The specific structure of the first yoke 5 of the yoke portion B is shown enlarged in FIG. In the figure, the inclination of the inner peripheral surface 5S and the inclination of the plunger 11 are exaggerated. The inner diameter of the bush 7 is smaller than the inner diameter of the inner peripheral surface 6S on the inner peripheral side of the yoke portion B, and this inner diameter is set slightly larger than the outer diameter of the plunger 11 (moving element). 1 to 3 show the outer peripheral surface 11s of the plunger 11 to be in contact with the inner periphery of the bush 7, but actually a slight gap is formed between them. Due to such a gap, the plunger 11 may be tilted with respect to the axial center X direction. becomes larger. Note that in FIG. 3, the axis X is not shown, and instead of the axis X, an imaginary line X' parallel to the axis X and along the inner peripheral surface 6S of the second yoke 6 is indicated by a dashed line. showing.

As shown in FIG. 3, the inner peripheral surface 5S is provided with a tapered portion 5Sa formed such that the inner diameter increases toward the front side of the plunger 11 in the direction of the imaginary line X' (axis X). Specifically, the inner diameter of the inner peripheral surface 6S of the second yoke 6 is used as a reference, and the inner diameter of the tapered portion 5Sa is gradually increased. As described above, as the plunger 11 moves toward the front side, the inclination with respect to the axial center X direction (virtual line X′) increases. The yoke portion B is formed at a predetermined inclination angle θ with respect to the imaginary line X′ (axis X) of the yoke portion B so that the distance L from the corner portion 11c intersecting with 11f is constant.

A hard layer such as nickel-phosphorus plating may be formed on the inner peripheral surface of the bush 7 and the inner peripheral surfaces 5S and 6S of the yoke portion B. A resin film having high toughness, chemical stability and low coefficient of friction may be formed.

[Action and effect of the embodiment]
Thus, in this embodiment, the inner peripheral surface 5S of the first yoke 5 is provided with the tapered portion 5Sa formed such that the inner diameter increases toward the front side in the axis X direction of the plunger 11 . Therefore, even if the plunger 11 is tilted with respect to the axis X when the plunger 11 protrudes, the outer peripheral surface 11s of the plunger 11 does not come too close to the inner peripheral surface 5S of the first yoke 5. A predetermined distance L can be secured between the inner peripheral surface 5S. As a result, it is possible to suppress the generation of lateral force due to the electromagnetic force on the plunger 11 . As a result, the electromagnetic force from the excitation coil A can effectively act on the movement of the plunger 11 in the direction of the axial center X, and the smooth operation of the plunger 11 can be realized.

Further, by providing the tapered portion 5Sa on the inner peripheral surface 5S, it is not necessary to reduce the clearance between the plunger 11 and the bush 7, so that a clearance that enables oil lubrication can be reliably secured between the two. can. As a result, it is possible to prevent the oil film from running out on the outer peripheral surface 11s of the plunger 11, and to prevent the wear resistance of the plunger 11 and the bush 7 from deteriorating.

Furthermore, in this embodiment, the tapered portion 5Sa is formed with a predetermined inclination angle θ with respect to the axis X of the yoke portion B. As shown in FIG. As a result, even if the plunger 11 is inclined with respect to the axis X, the corner portion 11c where the outer peripheral surface 11s of the plunger 11 intersects the front end surface 11f and the inner peripheral surface 5S (tapered portion 5Sa) of the yoke portion B are formed. is stably maintained. As a result, the electromagnetic force acting on the plunger 11 can be made substantially constant regardless of the amount of protrusion of the plunger 11 during the protrusion operation. As a result, the electromagnetic force can be applied more effectively to the movement of the plunger 11 in the direction of the axial center X, and the deterioration of the operating efficiency of the electromagnetic solenoid 100 can be suppressed. Moreover, since the tapered portion 5Sa can be formed as an inclined surface in which the inner peripheral surface 5S is smoothly inclined, the yoke portion B can be manufactured easily.

[Another embodiment]
The present invention may be configured as follows other than the above-described embodiments (components having the same functions as those of the embodiments are given the same numbers and symbols as those of the embodiments).

(1) The inner diameter of the inner peripheral surface 5S of the yoke portion B may have a shape that expands stepwise or non-linearly toward the downstream side in the operating direction of the plunger 11 . That is, as in the above-described embodiment, when the second cylindrical portion 6a of the second yoke 6 is located at the outer peripheral position of the plunger 11 when the electromagnetic solenoid 100 is not operated, the inner peripheral surface 5S moves toward the front side. A shape that changes so as to increase in diameter stepwise, or a shape in which the inner peripheral surface 5S curves so that the radially inner direction is convex toward the radially outer direction may be used.

Even with such a configuration, the outer surface of the plunger 11 does not come into close contact with the inner peripheral surface 5S, suppressing magnetic short-circuiting and directing the electromagnetic force from the excitation coil A in the axial center X direction of the plunger 11. It is possible to effectively act on the movement of

(2) The electromagnetic solenoid 100 may be used, for example, as an actuator for positioning equipment.

INDUSTRIAL APPLICABILITY The present invention can be used for an electromagnetic solenoid that linearly actuates a mover by an electromagnetic force acting from a yoke when an excitation coil is energized.

5: First yoke 5S: First inner peripheral surface 5Sa: Tapered portion 5a: First tubular portion 6: Second yoke 6S: Second inner peripheral surface 6a: Second tubular portion 7: Bushing 11: Plunger (movable Child)
11c: corner portion 11s: outer peripheral surface 11f: front end surface 11r: rear end surface 12: shaft 14: narrowed portion 15: thin portion (middle portion)
100: electromagnetic solenoid A: excitation coil B: yoke portion (stator)
C: Housing L: Distance S: Spool X: Axis X': Virtual line θ: Tilt angle

Claims (2)

an exciting coil that generates magnetic flux when energized;
a stator disposed on the inner peripheral side of the excitation coil, made of a cylindrical magnetic material centered on the axis, and serving as a magnetic path for the magnetic flux;
a cylindrical mover made of a magnetic material, which is accommodated in the inner space of the stator so as to be movable along the axis by the electromagnetic force generated by the magnetic flux;
Provided on the mover so as to be coaxial with the axis of the mover, projecting to one side in the axial direction of the stator integrally with the mover, and retreating to the other side in the axial direction of the stator. a working shaft;
It is fixed to the inner peripheral surface of the stator from the other end in the axial direction of the stator toward the middle portion in the axial direction of the stator, and supports the outer peripheral surface of the mover. and a bushing for
Within the inner peripheral surface of the stator, in the range where the end surface of the mover on the one side in the axial direction of the stator protrudes from the intermediate portion, the inner diameter of the bush is increased. By having a larger inner diameter, a gap is formed between the inner peripheral surface of the stator and the outer peripheral surface of the mover, and the inner diameter increases toward the one side in the axial direction of the stator. An electromagnetic solenoid provided with a tapered portion formed to When the mover inclines with respect to the axis of the stator as the mover moves to the one side in the axial direction of the stator, the tapered portion is aligned with the outer peripheral surface of the mover. 2. The electromagnetic solenoid according to claim 1, which is formed at a predetermined inclination angle with respect to the axial center of said stator so that the distance between is constant.

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