JP4858284B2 - Electromagnetic actuator - Google Patents

Description

  The present invention relates to an electromagnetic actuator in which a plunger is coupled to a shaft that is slidably supported in the axial direction, and the plunger is slidably supported via the shaft.

An example of an electromagnetic actuator in which a plunger is slidably supported via a shaft will be described with reference to FIG.
The electromagnetic actuator J1 shown in FIG. 6 drives a spool valve (valve) J2 having a three-way valve structure, and includes a coil J3, a plunger (magnetic mover) J4, and a magnetic stator J5.
The magnetic stator J5 is a part that forms a closed magnetic circuit around the coil J3, and has a first core stator J7 including a magnetic attracting part J6 that attracts the plunger J4 in the axial direction by a magnetic force, and a cylindrical shape that covers the periphery of the plunger J4. It is comprised with the 2nd core stator J8 provided with the magnetic delivery part which exhibited.
The first core stator J7 includes a shaft sliding portion (bearing part) J10 that supports a shaft J9 coupled to the plunger J4 so as to be slidable in the axial direction. As a result, the plunger J4 is slidably supported via the shaft J9.

The main part (magnetic attraction force generating part) of the electromagnetic actuator J1 in the prior art will be described with reference to FIG.
(A) As shown in FIG. 7A, the basic structure of the magnetic attraction force generating unit is such that the opposing surfaces of the magnetic attraction unit J6 and the plunger J4 are parallel. This type has the advantage of simple structure and easy manufacture. However, when the plunger J4 approaches the magnetic attraction unit J6, the attractive force of the plunger J4 suddenly increases.
(B) Therefore, as shown in FIG. 7B, a suction recess J11 into which the end of the plunger J4 can enter is formed in a part of the magnetic suction portion J6, and the first suction portion by the bottom surface of the suction recess J11. And the 2nd attraction | suction part by the cylinder part of attraction | suction recessed part J11 is provided, and the technique which relieved the malfunction which magnetic attraction force changes rapidly with respect to the stroke amount of plunger J4 is known.

(C) Further, as shown in FIG. 7C, a tapered portion J12 having a smaller diameter toward the magnetic attracting portion J6 side (the left side in the drawing) is provided on the outer peripheral surface of the plunger J4 near the magnetic attracting portion J6. A technique is also known in which the magnetic attraction force does not change with respect to the stroke amount of the plunger J4.
(D) Or, as shown in FIG. 7 (d), a tapered portion J13 having a small diameter toward the plunger J4 side (the right side in the figure) is provided on the outer peripheral surface of the cylindrical portion of the suction recess J11 near the plunger J4. A technique is also known in which the magnetic attraction force does not change with respect to the stroke amount of the plunger J4.

However, the techniques shown in the above (b) to (d) are directed to the cylindrical portion (outer diameter direction) of the suction recess J11 in addition to the “axial magnetic flux flow α” from the plunger J4 toward the bottom of the magnetic suction portion J6. An “outer diameter direction magnetic flux flow β” is generated. Since the magnetic attraction force due to the “outer radial direction magnetic flux flow β” acts as a radially outward force on the plunger J4, a force perpendicular to the axial direction acts on the shaft J9.
As a result, the shaft J9 is strongly rubbed against the shaft sliding portion J10, and the sliding resistance of the shaft J9 is increased.

In particular, as shown in Reference Example 1 described later, in the case where the shaft J9 is a type that is slidably supported only on the magnetic attraction portion J6 side (cantilever support type that is supported only on one side of the plunger J4), A radially outward force acts on the plunger J4 away from the shaft sliding portion J10, so that the shaft J9 gives a tilting force to the shaft sliding portion J10 on the lever principle. As a result, the shaft J9 is The sliding portion J10 is strongly rubbed, and a large sliding resistance acts on the shaft J9.
As described above, the increase in the sliding resistance of the shaft J9 leads to deterioration in the response of the plunger J4 and an increase in hysteresis.
Alternatively, wear may occur between the shaft J9 and the shaft sliding portion J10 due to long-term use, which may cause a tilt of the plunger J4 and a decrease in performance.

On the other hand, in the technique shown in (a) above, the outer diameter of the magnetic attraction portion J6 is usually larger than the outer diameter of the plunger J4, as shown in FIG. 7 (a). Then, the “outer diameter direction magnetic flux flow β” toward the larger diameter side of the magnetic attracting part J6 occurs, and the same problems as in the above (b) to (d) occur.
In the technique shown in (a) above, if the outer diameter of the magnetic attraction portion J6 is the same as the outer diameter of the plunger J4, the “outer diameter direction magnetic flux flow β” does not occur. That is, only the “axial magnetic flux flow α” from the plunger J4 toward the magnetic attraction portion J6 is generated. Therefore, the centering action of the shaft J9 by the generated magnetic force does not occur, and the action of reducing the sliding resistance of the shaft J9 by the generated magnetic force does not occur.
JP-A-9-166238

The present invention has been made in view of the above problems, and an object of the present invention is to provide an electromagnetic actuator capable of reducing the sliding resistance of the shaft by causing the shaft to be aligned using the generated magnetic force. It is in.
Specifically, for example, even if the “outer radial direction magnetic flux flow β” is generated, the sliding resistance by the “outer radial direction magnetic flux flow β” is generated by using the generated magnetic force to cause the shaft to be aligned. It is in the provision of an electromagnetic actuator that can suppress the increase of

The electromagnetic actuator of the present invention is a magnetic flux lens that directs the flow direction of the magnetic flux generated between the plunger and the magnetic attraction portion to the axial center on the shaft sliding portion side at a position facing the magnetic attraction portion in the plunger in the axial direction. Means are provided. The magnetic flux lens means is a concave portion formed on the plunger and recessed to a side different from the magnetic attraction portion. The concave portion has an arcuate spherical curved surface, and the center of the arcuate spherical curved surface is at the axial center of the shaft sliding portion.
The magnetic attraction force due to the “inner-diameter direction magnetic flux flow γ (sign, see FIG. 1)” toward the shaft center of the shaft sliding portion is adjusted to align the shaft to the shaft center on the shaft sliding portion side on the magnetic attraction portion side. Acts as a core force.
By this alignment operation, the sliding resistance of the shaft can be reduced, the response of the plunger can be improved, and the hysteresis can be reduced. Moreover, even if it is used for a long time, since the wear between the shaft and the shaft sliding portion is suppressed, it is possible to suppress the occurrence of tilting and rattling of the plunger. That is, the performance of the electromagnetic actuator can be enhanced and the reliability can be enhanced.

The electromagnetic actuator of the present invention is widely applicable as an actuator such as an electromagnetic valve, for example, and includes a non-magnetic shaft having a rod shape, a magnetic plunger coupled to the shaft, and a shaft as a shaft. And a magnetic core stator having a magnetic attraction part for magnetically attracting the plunger in the axial direction by a magnetic force.
A magnetic flux lens means for directing the flow direction of the magnetic flux generated between the plunger and the magnetic attraction portion toward the shaft center on the shaft sliding portion side is provided at the axially opposite portion between the plunger and the magnetic attraction portion. ing.
The magnetic flux lens means is a concave portion formed on the plunger and recessed to a side different from the magnetic attraction portion. The recess has an arcuate spherical curved surface, and the central part of the arcuate spherical curved surface is at the axial center of the shaft sliding portion.

Reference example 1

With reference to FIG. 1, the reference example 1 which provided the magnetic flux lens means 14 in the plunger 4 is demonstrated.
The electromagnetic actuator 1 shown in the reference example 1 is a driving means of an electromagnetic valve used for, for example, “OCV (oil flow control valve) of a VVT (valve variable timing device)”, “hydraulic control valve of an automatic transmission”, and the like. The electromagnetic valve is provided by integrating the valve {discloses only the valve housing 2 (for example, a sleeve or the like in FIG. 1)} and the electromagnetic actuator 1.

  Here, the valve can employ various structures. That is, various types of valves such as a spool valve and a ball valve can be applied, and various types of valves such as a two-way valve (open / close valve), a three-way valve, and a four-way valve can be applied. Of course, any type such as N / L (normally low) type, N / H (normally high) type, N / C (normally closed) type, N / O (normally open) type is adopted. It may be a thing.

The electromagnetic actuator 1 includes a coil 3, a plunger 4, a magnetic stator 5, and a connector (not shown).
The coil 3 generates a magnetic force when energized to form a magnetic flux loop passing through the plunger 4 and the magnetic stator 5. The coil 3 is a conductive wire (enameled wire) having an insulating coating around a resin bobbin. Etc.) are wound many times.

The plunger 4 is a magnetic metal (for example, a ferromagnetic material such as iron) having a substantially cylindrical shape. The plunger 4 is coupled (integrated) by press-fitting or the like with a shaft 6 that is slidably supported in the axial direction, and is slidably supported via the shaft 6.
The shaft 6 is a non-magnetic metal having a cylindrical rod shape, and the left end in FIG. 1A of the shaft 6 abuts on a valve body (for example, a spool or the like: not shown). For this reason, the driving force in the axial direction of the plunger 4 (magnetic attractive force acting on the plunger 4) is transmitted to the valve body via the shaft 6.
On the other hand, a return spring (not shown) that pushes back the valve body to the right side in FIG. 1A is arranged inside the valve, and the plunger 4 together with the valve body by the urging force of the return spring transmitted to the valve body is also on the right side in FIG. The plunger 4 is biased in a direction in which the plunger 4 and a magnetic attraction unit 9 described later are separated.

The magnetic stator 5 is a combination of a core stator 7 that magnetically attracts the plunger 4 in the axial direction and a substantially cup-shaped yoke 8 that covers the outer periphery of the coil 3.
The core stator 7 is a magnetic metal (for example, a ferromagnetic material such as iron) magnetically coupled to the opening end of the yoke 8, and a magnetic attraction portion 9 is provided at a position facing the plunger 4 in the axial direction. A magnetic attractive force generating part (main magnetic gap) is formed between the magnetic attractive part 9 and the plunger 4.
A shaft insertion hole 11 penetrating in the axial direction is formed at the center of the core stator 7. A shaft sliding portion that supports the shaft 6 so as to be slidable in the axial direction is provided inside the shaft insertion hole 11. The shaft sliding portion may be a bearing component (a member that enhances slidability such as a metal bearing) fixed inside the shaft insertion hole 11, or may be an inner peripheral surface of the shaft insertion hole 11. good.

The yoke 8 is a magnetic metal (for example, a ferromagnetic material such as iron) having a double cylinder cup shape, and covers the circumference of the large diameter cylindrical cylinder yoke 12 covering the circumference of the coil 3 and the plunger 4. The small-diameter cylindrical magnetic delivery cylinder 13 has a shape coupled with the annular portion on the right side of FIG.
A thin claw portion is formed in the cup opening of the yoke 8, and after the components of the electromagnetic actuator 1 (parts in which the core stator 7 and the coil 3 are resin-molded) are incorporated in the yoke 8, the claw is formed. By crimping the part, the electromagnetic actuator 1 and the valve are firmly coupled.
The magnetic delivery cylinder 13 covers the periphery of the plunger 4 in a non-contact manner, and performs radial magnetic delivery with the plunger 4.

As shown in FIG. 1B, the magnetic attraction portion 9 in the reference example 1 has a flow direction of magnetic flux generated between the plunger 4 and the magnetic attraction portion 9 at a portion facing the plunger 4 in the axial direction. Is provided with magnetic flux lens means 14 for directing the shaft toward the axial center of the shaft sliding portion.
The magnetic flux lens means 14 is a convex portion in which the axial center portion of the magnetic attracting portion 9 bulges toward the plunger 4, and the surface of the convex portion facing the plunger 4 exhibits an arcuate spherical curved surface.

When the coil 3 is energized, a magnetic flux flows on the opposing surface of the magnetic attraction unit 9 and the plunger 4. The flow direction of the magnetic flux is directed to the axial center of the shaft sliding portion by the magnetic flux lens means 14. Specifically, as shown in FIG. 1B, the flow direction of the magnetic flux converges toward the center of the arc constituting the magnetic flux lens means 14.
As described above, in Reference Example 1 , when the coil 3 is energized, an “inner diameter direction magnetic flux flow γ” is generated from the plunger 4 toward the axial center of the shaft sliding portion.

Embodiment 1 will be described with reference to FIG. In addition, below, the same code | symbol as the said reference example 1 shows the same function thing.
In the reference example 1 described above, the example in which the magnetic flux lens means 14 is provided in the magnetic attraction portion 9 of the core stator 7 has been shown.
On the other hand, in the first embodiment , magnetic flux lens means 14 is provided on the plunger 4 side.
When the magnetic flux lens means 14 is provided on the plunger 4 side as shown in the first embodiment, the flow direction of the magnetic flux generated between the plunger 4 and the magnetic attraction unit 9 is determined based on the axial center of the shaft 6 on the magnetic attraction unit 9 side. The magnetic flux lens means 14 is provided as a concave portion that is recessed toward a different side from the magnetic attracting portion 9 (same as the shaft center of the shaft sliding portion). Specifically, the surface of the concave portion of the first embodiment facing the magnetic attraction portion 9 is provided on an arcuate spherical curved surface, and the central portion of the arcuate spherical curved surface is the axis center of the shaft sliding portion. Provided.

Even when the coil 3 is provided as in the first embodiment , when the coil 3 is energized, the flow direction of the magnetic flux is directed to the axial center of the shaft 6 on the magnetic attracting unit 9 side by the magnetic flux lens means 14. Specifically, the flow direction of the magnetic flux converges toward the central part of the arc constituting the magnetic flux lens means 14, and “the inner diameter direction magnetic flux flow γ” is generated as in the first reference example .

The magnetic attraction force generated by the “inner diameter direction magnetic flux flow γ” acts as an alignment force for aligning the shaft 6 to the center of the shaft sliding portion. For this reason, the sliding resistance of the shaft 6 can be reduced, and the smooth movement of the plunger 4 can be realized. Thereby, the response of the plunger 4 can be improved and the hysteresis can be reduced.
In addition, since the sliding resistance of the shaft 6 can be reduced, wear between the shaft 6 and the shaft sliding portion can be suppressed, and even if the operation is repeated over a long period of time, the backlash and inclination of the shaft 6 are generated. Can be suppressed.
That is, the performance and reliability of the electromagnetic actuator 1 can be improved, and the performance and reliability of the electromagnetic valve can be improved.
Furthermore, since the magnetic flux lens means 14 is provided by a part of the magnetic attraction unit 9, the number of parts is not increased, and an increase in cost can be suppressed.

[Modification]
In the first embodiment, the example in which the present invention is applied to the magnetic attraction force generation unit of the type (a) described in the section of “Background Art” has been described. However, the magnetism of the types (b) to (d) is shown. The present invention may be applied to the suction force generation unit.
Specifically, FIG. 3 shows an example in which the present invention is applied to the type (b), FIG. 4 shows an example in which the present invention is applied to the type (c), and the present invention is applied to the type (d). An example of this is shown in FIG. 3 to 5, as described above, the force in the direction perpendicular to the axial direction acts on the shaft 6 by the “outer-diameter direction magnetic flux flow β”, but the magnetic flux lens means 14 is provided. The centering action is applied to the shaft 6 by the “inner diameter direction magnetic flux flow γ”, and an increase in sliding resistance due to the “outer diameter direction magnetic flux flow β” can be suppressed.

Both magnetic attraction portion 9 and the plunger 4 may be provided a magnetic flux lens means 14. Thus, when providing the magnetic flux lens means 14 in both the magnetic attraction part 9 and the plunger 4, the convex part and the concave part can overlap with each other in the axial direction, and the reduction in the stroke width of the plunger 4 can be suppressed.
In the above embodiment, an example of forming a magnetic flux lens unit 14 to the flop plunger 4 may be provided with magnetic flux lens unit 14 separately. Thus, by providing the magnetic flux lens means 14 separately, the present invention can be applied to the existing electromagnetic actuator 1.

The configuration of the magnetic stator 5 shown in the above embodiment shows a specific example, and other configurations may be adopted.
In the above embodiment, the example in which the present invention is applied to the electromagnetic actuator 1 that drives the valve has been described. However, the present invention may be applied to the electromagnetic actuator 1 that drives the driven body other than the valve via the shaft 6. good.

It is a schematic sectional drawing in alignment with the axial direction of an electromagnetic actuator, and principal part sectional drawing of a magnetic attraction force generation part ( reference example 1 ). It is principal part sectional drawing of a magnetic attraction force generation | occurrence | production part ( Example 1 ). It is principal part sectional drawing of a magnetic attraction force generation | occurrence | production part (modification example). It is principal part sectional drawing of a magnetic attraction force generation | occurrence | production part (modification example). It is principal part sectional drawing of a magnetic attraction force generation | occurrence | production part (modification example). It is sectional drawing which follows the axial direction of a solenoid valve (conventional example). It is principal part sectional drawing of a magnetic attraction force generation | occurrence | production part (conventional example).

DESCRIPTION OF SYMBOLS 1 Electromagnetic actuator 4 Plunger 6 Shaft 7 Core stator 9 Magnetic attraction part 14 Magnetic flux lens means

Claims (1)

A shaft made of non-magnetic material presenting a rod shape;
A magnetic plunger coupled to the shaft;
A magnetic core stator having a shaft sliding portion that slidably supports the shaft in the axial direction, and a magnetic attraction portion that magnetically attracts the plunger in the axial direction by a magnetic force;
In an electromagnetic actuator comprising:
Magnetic flux lens means for directing the flow direction of magnetic flux generated between the plunger and the magnetic attraction portion toward the shaft center on the shaft sliding portion side at the axially opposing portion of the plunger and the magnetic attraction portion Is provided ,
The magnetic flux lens means is a concave portion formed on the plunger and recessed to a side different from the magnetic attraction portion.
The recess has an arcuate spherical curved surface, and the central part of the arcuate spherical curved surface is at the axial center of the shaft sliding part .

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