WO2018030053A1

WO2018030053A1 - Solenoid actuator

Info

Publication number: WO2018030053A1
Application number: PCT/JP2017/025135
Authority: WO
Inventors: 剛史弘中; 喜也永溝
Original assignee: Ｋｙｂ株式会社
Priority date: 2016-08-10
Filing date: 2017-07-10
Publication date: 2018-02-15
Also published as: JP6379142B2; JP2018026474A

Abstract

A solenoid actuator (20) is provided with a coil (41) for generating magnetic force in accordance with a supplied current, a fixed core (50) that is excited by the magnetic force of the coil (41), and a plunger (60) that is attracted by the excited fixed core (50) and moved in the axial direction. The fixed core (50) has a body part (50a) facing the axial direction in relation to the plunger (60), and an extension part (51) that extends from the outer edge side of the body part (50a) toward the plunger (60) and surrounds the end of the plunger (60), the saturation magnetic flux density of the extension part (51) being set to be lower than that of the body part (50a).

Description

Solenoid actuator

The present invention relates to a solenoid actuator.

JP 2004-218816A includes a coil that generates a magnetic force according to a supplied current, a fixed iron core that is excited by the magnetic force of the coil, and a movable iron core that moves in the axial direction by the attractive force of the excited fixed iron core. A provided solenoid actuator is disclosed.

The fixed core of this solenoid actuator has an extending part surrounding the end of the movable core, and the end of the movable core is accommodated in a recess formed by the extending part.

However, in the solenoid actuator described in JP2004-218816A, hysteresis may occur when the moving direction of the movable core changes due to the frictional force generated between the extension portion of the fixed core and the movable core. Such a phenomenon is caused in particular by the fact that the magnetic flux passing between the movable iron core and the extension portion increases, and the force that the extension portion attracts the movable iron core, that is, the force acting in the radial direction on the movable iron core. It becomes remarkable by becoming large.

An object of the present invention is to suppress hysteresis and improve the controllability of a solenoid actuator.

According to an aspect of the present invention, the solenoid actuator includes a coil that generates a magnetic force according to a supplied current, a fixed iron core that is excited by the magnetic force of the coil, and an axial direction that is attracted to the excited fixed iron core. A movable iron core that moves to the movable iron core, and the fixed iron core extends from the outer edge side of the main body portion toward the movable iron core. An extension part surrounding the periphery of the end part, and a saturation magnetic flux density in the extension part is set lower than that of the main body part.

FIG. 1 is a longitudinal sectional view of an actuator device including a solenoid actuator according to an embodiment of the present invention. FIG. 2 is a graph (BH curve) showing the change in magnetic flux density with respect to the magnetic field strength of the members constituting the magnetic circuit. FIG. 3 is a diagram showing a distribution state of magnetic flux passing between the movable iron core and the fixed iron core. FIG. 4 is a diagram illustrating a distribution state of magnetic flux passing between the movable iron core and the fixed iron core. FIG. 5 is a longitudinal sectional view of an actuator device including a modification of the solenoid actuator according to the embodiment of the present invention.

Hereinafter, an actuator device 1 including a solenoid actuator 20 according to an embodiment of the present invention will be described with reference to FIG.

As shown in FIG. 1, the actuator device 1 includes a solenoid actuator 20 and a valve device 10 driven by the solenoid actuator 20.

The valve device 10 is a spool valve installed in a flow path through which a working fluid such as hydraulic oil flows, and includes a cylindrical valve sleeve 11 and a spool 12 slidably provided in the valve sleeve 11. A flow path (not shown) is connected to each side opening of the valve sleeve 11.

In the valve device 10, the flow rate of the working fluid flowing through the valve device 10 is changed by changing the communication opening degree that communicates each flow path according to the position of the spool 12. The position of the spool 12 is controlled by the solenoid actuator 20.

The solenoid actuator 20 includes a coil 41 wound around the bobbin 40, a fixed core 50 as a fixed iron core fitted on the inner peripheral side of the bobbin 40, and a yoke 52 connected to the fixed core 50 via a nonmagnetic material 53. A plunger 60 as a movable iron core slidably supported by the fixed core 50 and the yoke 52, a spring 62 interposed between the fixed core 50 and the plunger 60 in a compressed state, and A case 30 to be accommodated.

The plunger 60 is a cylindrical member having a through hole 60a through which the shaft 61 is inserted in the shaft center, and is formed of a magnetic material. The plunger 60 has one end surface 60 b disposed on the fixed core 50 side, the other end surface 60 c provided on the opposite side of the one end surface 60 b, and an outer peripheral surface 60 d slidably contacting the fixed core 50 and the yoke 52.

The shaft 61 inserted through the through-hole 60a is a rod-shaped member formed of a nonmagnetic material such as stainless steel, and the plunger 60 is caulked and fixed to the outer peripheral surface of the shaft 61. The shaft 61 penetrates the plunger 60 in the axial direction, and both end portions of the shaft 61 protrude from both

end surfaces

60 b and 60 c of the plunger 60. A hook-shaped spring receiving portion 61a having an outer diameter larger than that of the through hole 60a is formed at the end portion of the shaft 61 protruding from the one end surface 60b side of the plunger 60. The end portion of the shaft 61 protruding from the other end surface 60c side of the plunger 60 is coupled to the spool 12 of the valve device 10 by a coupling means (not shown).

The fixed core 50 is a columnar member made of a magnetic material, and has a main body portion 50a that is opposed to the plunger 60 in the axial direction, and extends from the outer edge side of the main body portion 50a toward the plunger 60. It has an annular extending part 51 that surrounds the periphery of the end part on the end face 60b side, and an accommodation hole 50b that is formed in the main body part 50a and accommodates the spring 62. A concavity is formed at the end of the fixed core 50 by the facing surface 50c of the main body 50a facing the one end surface 60b of the plunger 60 and the inner peripheral surface 51a of the extending portion 51. The end portion on the one end surface 60b side of 60 is slidably accommodated.

Further, the fixed core 50 is formed so that the magnetic characteristics of the extending part 51 and the magnetic characteristics of the main body part 50a are different by magnetic annealing of the part other than the extending part 51.

Here, with reference to FIG. 2, the difference in magnetic characteristics between the extension part 51 and the main body part 50a will be described. In the graph shown in FIG. 2, the solid line indicates the magnetic saturation curve (BH curve) of the main body 50a, and the broken line indicates the magnetic saturation curve (BH curve) of the extension 51.

Generally, the magnetic flux density flowing through the magnetic material increases as the magnetic field becomes stronger. However, when the magnetic field becomes a certain strength, the rate of increase of the magnetic flux density decreases, and the magnetic flux density is in an overcrowded state in the magnetic material. Eventually, the magnetic flux density flowing through the magnetic material becomes a substantially constant magnetic flux density, so-called saturation magnetic flux density, regardless of the strength of the magnetic field.

As shown in FIG. 2, the saturation magnetic flux density in the extension part 51 that has not been magnetically annealed is lower than the saturation magnetic flux density of the magnetically annealed main body part 50a. Further, the magnetic permeability indicating the change rate of the magnetic flux density with respect to the strength of the magnetic field is always smaller in the extension part 51 that is not magnetically annealed than in the main body part 50a that is magnetically annealed. That is, the extending part 51 has a magnetic characteristic that is more easily magnetically saturated than the main body part 50a. Thus, the effect by making the magnetic characteristic of the extension part 51 different from the magnetic characteristic of the main body part 50a will be described later.

The yoke 52 is a member formed of a magnetic material, a cylindrical portion 52a inserted on the inner peripheral side of the bobbin 40, a flange portion 52b formed to protrude radially outward from an end portion of the cylindrical portion 52a, And a sliding hole 52c formed penetrating from the cylindrical portion 52a to the flange portion 52b. The end of the plunger 60 on the other end surface 60 c side is slidably supported by the sliding hole 52 c of the yoke 52.

The fixed core 50 and the yoke 52 are connected in the axial direction by a cylindrical nonmagnetic material 53 formed of a nonmagnetic material. For this reason, the yoke 52 and the fixed core 50 are in a state of being separated in the axial direction. The nonmagnetic material 53 may be formed of a material having a low magnetic permeability such as aluminum, or may be a space formed between the yoke 52 and the fixed core 50.

The space on the fixed core 50 side partitioned by the plunger 60 and the space on the yoke 52 side are always communicated by a plurality of communication grooves 60e formed in the outer peripheral surface 60d of the plunger 60 along the axial direction. For this reason, the working fluid in each space can move through the communication groove 60e according to the movement of the plunger 60. Therefore, the movement of the plunger 60 is not hindered by the working fluid.

The spring 62 is a coil spring that biases the plunger 60 in a direction opposite to the attractive force acting on the plunger 60 when the coil 41 is energized. One end of the spring 62 is locked to the spring receiving portion 61 a of the shaft 61, and the other end of the spring 62 is received and locked in the receiving hole 50 b of the fixed core 50.

The case 30 is a bottomed cylindrical member formed of a magnetic material and accommodates each member constituting the solenoid actuator 20. The open end of the case 30 is configured as a caulking portion for caulking and fixing one end of the valve sleeve 11 with the flange portion 52 b of the yoke 52 sandwiched between the bobbin 40 and the valve sleeve 11.

The bobbin 40 is a cylindrical member having flanges at both ends, and is formed of a resin having electrical insulation. A conductive wire wound around the outer peripheral surface of the bobbin body between the flanges constitutes the coil 41. A terminal 42 that is electrically connected to the coil 41 is provided on one flange of the bobbin 40.

One end of the terminal 42 protrudes to the outside through a notch portion of the case 30 with the bobbin 40 disposed in the case 30. When a current is supplied to the coil 41 via the terminal 42, a magnetic field is generated around the coil 41. The fixed core 50, the plunger 60, the yoke 52, and the case 30 disposed so as to surround the coil 41 serve as a path through which magnetic flux flows when a magnetic field is generated around the coil 41, a so-called magnetic circuit. In addition, as a magnetic material which forms these members which comprise a magnetic circuit, steel materials with comparatively high magnetic permeability, such as SUM23, MES3F, SUY, SS330, ELCH2, etc., are used, for example.

Next, the operation of the actuator device 1 configured as described above will be described.

In the actuator device 1, when no current is supplied to the coil 41 of the solenoid actuator 20, the plunger 60 is biased in the direction of arrow A in FIG. At this time, the spool 12 comes into contact with a stopper portion provided on the valve sleeve 11, and the plunger 60 and the spool 12 are stopped at the initial position shown in FIG.

When a current exceeding a predetermined value is supplied to the coil 41 of the solenoid actuator 20, the fixed core 50 is excited by the magnetic field generated around the coil 41, and the plunger 60 is drawn toward the fixed core 50 in the axial direction. That is, the plunger 60 moves in the direction of arrow B in FIG. As the plunger 60 moves, the spool 12 connected to the plunger 60 via the shaft 61 also moves. The spool 12 moves to a position where the magnetic attractive force acting on the plunger 60 and the urging force of the spring 62 acting on the plunger 60 are balanced. As the spool 12 moves, the flow rate of the hydraulic oil that flows into the flow path through the valve sleeve 11 is adjusted.

Since the magnetic attractive force acting on the plunger 60 changes according to the magnitude of the current supplied to the coil 41, the stroke amount of the spool 12, that is, the valve is changed by changing the current value supplied to the coil 41. The flow rate of the hydraulic oil flowing into the flow path through the sleeve 11 can be arbitrarily controlled. Thus, the solenoid actuator 20 operates as a proportional solenoid actuator.

Subsequently, with reference to FIGS. 3 and 4, the magnetic flux passing between the plunger 60 and the fixed core 50 when the current is supplied to the coil 41 and the influence of the magnetic flux will be described. FIG. 3 is a diagram schematically showing the distribution state of magnetic flux when the extending portion 51 of the fixed core 50 and the main body portion 50a have the same magnetic characteristics as in the prior art, and FIG. Thus, it is the figure which showed roughly the distribution state of the magnetic flux in case the saturation magnetic flux density in the extension part 51 is set lower than the saturation magnetic flux density of the main-body part 50a.

When the extending portion 51 and the main body portion 50a have the same magnetic characteristics, as shown in FIG. 3, the radial magnetic flux 65a flowing from the outer peripheral surface 60d of the plunger 60 toward the extending portion 51 and one of the plungers 60 are provided. The axial magnetic flux 65b flowing from the end surface 60b toward the main body 50a is distributed at substantially equal intervals.

On the other hand, when the saturation magnetic flux density in the extension part 51 is set lower than the saturation magnetic flux density of the main body part 50a, as shown in FIG. 4, it flows from the outer peripheral surface 60d of the plunger 60 toward the extension part 51. The radial magnetic flux 65a is less than the axial magnetic flux 65b flowing from the one end surface 60b of the plunger 60 toward the main body 50a. This is because the main body part 50 a has a magnetic property that is less likely to be magnetically saturated than the extension part 51, so that the magnetic flux passing between the plunger 60 and the fixed core 50 is less than the extension part 51. It is because it becomes easy to flow toward.

Here, as shown in FIG. 3, when the radial magnetic flux 65a flowing from the outer peripheral surface 60d of the plunger 60 toward the extending portion 51 is relatively large, the force that the extending portion 51 attracts the plunger 60, that is, The force acting in the radial direction on the plunger 60 is increased. When the radial force acting on the plunger 60 is large as described above, the plunger 60 is pressed against the extending portion 51, and the frictional force generated between the extending portion 51 and the plunger 60 increases. Therefore, hysteresis may occur when the moving direction of the plunger 60 changes.

On the other hand, in this embodiment, as shown in FIG. 4, the radial magnetic flux 65 a flowing from the outer peripheral surface 60 d of the plunger 60 toward the extending portion 51 is relatively small. For this reason, the force which acts on the plunger 60 in the radial direction is reduced, and the frictional force generated between the extending portion 51 and the plunger 60 is also reduced. Therefore, the occurrence of hysteresis when the moving direction of the plunger 60 changes is suppressed, and as a result, the controllability of the solenoid actuator 20 can be improved.

The solenoid actuator 20 of the actuator device 1 according to the above embodiment has the following effects.

In the solenoid actuator 20, the saturation magnetic flux density in the extending part 51 is set lower than that of the main body part 50a. For this reason, the magnetic flux passing between the plunger 60 and the fixed core 50 becomes easier to flow toward the main body 50 a than the extension 51. As a result, the force acting in the radial direction on the plunger 60 is reduced, and the frictional force generated between the extending portion 51 and the plunger 60 is also reduced. By reducing the frictional force, the occurrence of hysteresis when the moving direction of the plunger 60 changes is suppressed, and as a result, the controllability of the solenoid actuator 20 can be improved.

Next, a modification of the solenoid actuator 20 according to the above embodiment will be described.

In the solenoid actuator 20, the extending part 51 is formed integrally with the main body part 50a. Instead of this, as shown in FIG. 5, the extending portion 51 may be formed of a member different from the main body portion 50a.

In this modification, the extending part 51 is formed in an annular shape and is fitted and fixed to a step part 50d formed on the facing surface 50c of the main body part 50a. And the extension part 51 is formed with the steel material which is more easily magnetically saturated than the main-body part 50a, ie, the steel material with a low saturation magnetic flux density. Specifically, the main body 50a is formed of ELCH2, and the extension 51 is formed of SUM 23 that is more easily magnetically saturated than ELCH2. In addition, as a combination of the material of the main-body part 50a and the extension part 51, it is not limited to this, The extension part 51 should just be formed with the steel material which is more easily magnetically saturated than the main-body part 50a, for example, a main-body part 50a may be formed of ELCH2 that is magnetically annealed, and the extension 51 may be formed of ELCH2 that is not magnetically annealed.

Since the extending portion 51 is formed of a member different from the main body portion 50a as described above, steel materials having different saturation magnetic flux densities can be combined in various ways, so that desired solenoid characteristics can be realized. In addition, the fixed core 50 can be easily formed as compared with the case where the portion excluding the extended portion 51 of the fixed core 50 in which the extended portion 51 and the main body portion 50a are integrally formed is magnetically annealed.

In the solenoid actuator 20, the material of the plunger 60, the yoke 52, and the case 30 constituting the magnetic circuit is not specified, but these are formed of a material having a saturation magnetic flux density higher than that of the extending portion 51. Is preferred. For example, the fixed core 50, the plunger 60, the yoke 52, and the case 30 are formed of the same magnetic material, and the portion other than the extension portion 51 of the fixed core 50 is magnetically annealed so that the magnetic saturation is less likely than the extension portion 51. You may make it become a magnetic characteristic. As materials for the fixed core 50, the plunger 60, the yoke 52, and the case 30, steel materials other than SUM23, MES3F, SUY, SS330, and ELCH2 may be used as long as they have a relatively high magnetic permeability.

In the solenoid actuator 20, the shaft 61 is fixed to the plunger 60. Alternatively, the shaft 61 may be inserted into the through hole 60a of the plunger 60 with play. In this case, in order to prevent the plunger 60 from coming out of the yoke 52, a retaining member such as a C-shaped ring is provided in the sliding hole 52 c of the yoke 52.

Hereinafter, the configuration, operation, and effect of the embodiment of the present invention will be described together.

The solenoid actuator 20 includes a coil 41 that generates a magnetic force according to a supplied current, a fixed core 50 that is excited by the magnetic force of the coil 41, and a plunger 60 that is attracted to the excited fixed core 50 and moves in the axial direction. The fixed core 50 includes a main body portion 50a that faces the plunger 60 in the axial direction, and an extension portion that protrudes from the outer edge side of the main body portion 50a toward the plunger 60 and surrounds the periphery of the end portion of the plunger 60. 51, and the saturation magnetic flux density in the extending part 51 is set lower than that of the main body part 50a.

In this configuration, the saturation magnetic flux density in the extending part 51 is set lower than that of the main body part 50a. That is, the extending part 51 has a magnetic characteristic that is more easily magnetically saturated than the main body part 50a. For this reason, the magnetic flux passing between the plunger 60 and the fixed core 50 becomes easier to flow toward the main body 50 a than the extension 51. As a result, the force acting in the radial direction on the plunger 60 is reduced, and the frictional force generated between the extending portion 51 and the plunger 60 is also reduced. By reducing the frictional force, the occurrence of hysteresis when the moving direction of the plunger 60 changes is suppressed, and as a result, the controllability of the solenoid actuator 20 can be improved.

Further, the fixed core 50 is magnetically annealed except for the extending portion 51.

In this configuration, the magnetic properties of the main body 50a are less likely to be magnetically saturated than the extending portion 51 by magnetically annealing the portion other than the extending portion 51. For this reason, the magnetic flux passing between the plunger 60 and the fixed core 50 becomes easier to flow toward the main body 50 a than the extension 51. As a result, the force acting in the radial direction on the plunger 60 is reduced, and the frictional force generated between the extending portion 51 and the plunger 60 is also reduced. By reducing the frictional force, the occurrence of hysteresis when the moving direction of the plunger 60 changes is suppressed, and as a result, the controllability of the solenoid actuator 20 can be improved.

Further, the extending part 51 is a separate member from the main body part 50a, and is formed of a material having a saturation magnetic flux density lower than that of the main body part 50a.

In this configuration, the extending portion 51 and the main body portion 50a are formed of different members, and the extending portion 51 is formed of a material that is more easily magnetically saturated than the main body portion 50a. Therefore, since steel materials having different saturation magnetic flux densities can be combined in various ways, desired solenoid characteristics can be realized.

Moreover, the magnetic permeability in the extending part 51 is set lower than that of the main body part 50a.

In this configuration, the magnetic permeability in the extending part 51 is set lower than that of the main body part 50a. That is, the density of the magnetic flux flowing from the plunger 60 toward the extending part 51 is always lower than the density of the magnetic flux flowing from the plunger 60 toward the main body part 50a even if the strength of the magnetic field changes. As a result, the force acting in the radial direction on the plunger 60 is reduced, and the frictional force generated between the extending portion 51 and the plunger 60 is also reduced. By reducing the frictional force, the occurrence of hysteresis when the moving direction of the plunger 60 changes is suppressed, and as a result, the controllability of the solenoid actuator 20 can be improved.

The embodiment of the present invention has been described above. However, the above embodiment only shows a part of application examples of the present invention, and the technical scope of the present invention is limited to the specific configuration of the above embodiment. Absent.

For example, the solenoid actuator 20 is a so-called pull type that displaces the spool 12 toward the coil 41 by energizing the coil 41. Instead of this, the solenoid actuator may be a so-called push type that displaces the spool 12 to the opposite side to the coil 41 by energizing the coil 41.

Further, the solenoid actuator 20 drives the spool 12 connected to the plunger 60. Instead of this, the solenoid actuators 20 and 21 may drive the poppet valve by the plunger 60. The valve element driven by the plunger 60 may be any type of valve element as long as it adjusts the opening of the flow path.

This application claims priority based on Japanese Patent Application No. 2016-155792 filed with the Japan Patent Office on August 10, 2016, the entire contents of which are incorporated herein by reference.

Claims

A solenoid actuator,
A coil that generates a magnetic force according to the supplied current;
A fixed iron core excited by the magnetic force of the coil;
A movable iron core that is attracted to the magnetized fixed iron core and moves in the axial direction;
The fixed iron core includes a main body that faces the movable iron core in the axial direction, and an extending portion that extends from an outer edge side of the main body toward the movable iron core and surrounds the periphery of the end of the movable iron core. And having
A solenoid actuator in which a saturation magnetic flux density in the extension portion is set lower than that of the main body portion.
The solenoid actuator according to claim 1,
The fixed iron core is a solenoid actuator in which a portion excluding the extending portion is magnetically annealed.
The solenoid actuator according to claim 1,
The extension portion is a solenoid actuator formed of a material different from the main body portion and having a saturation magnetic flux density lower than that of the main body portion.
The solenoid actuator according to claim 1,
The solenoid actuator in which the magnetic permeability in the extension part is set lower than that of the main body part.