JP2023141546A - solenoid device - Google Patents

Abstract

To provide a solenoid device in which a plunger strengthens suction force in a direction toward the bottom of a core near the end position of the plunger's movement.SOLUTION: A solenoid device 1 includes a cylindrical bobbin 2 having a through hole extending along the axial direction, a coil 3 wound around the outer circumference of the bobbin 2, a cylindrical core 4 made of a magnetic material, disposed in the through hole of the bobbin 3, and having a bottom on one side in the axial direction, and a columnar or cylindrical plunger 8 that is placed inside the core 4 and moves toward the bottom of the core 4 by the magnetic force generated when the coil 3 is energized, and the inner circumferential surface of the core 4 has a tapered slope whose inner diameter gradually decreases from the bottom on one axial side toward the other axial side.SELECTED DRAWING: Figure 1

Description

The present invention relates to a solenoid device.

As an example of a solenoid device, a solenoid device described in Patent Document 1 is known. The solenoid device described in Patent Document 1 includes a cylindrical bobbin that passes through the bobbin in the axial direction, a coil wound around the outer circumference of the bobbin, and a magnetic material, and is arranged on one side of the through hole in the axial direction. A cylindrical core made of a magnetic material, and a cylindrical yoke that is arranged on the other axial side of the through hole and is not magnetically continuous with the core but adjacent to the core, and a cylindrical yoke that is magnetically discontinuous between the core and the yoke. and a cylindrical resin member that is held in a stable state.

Japanese Patent Application Publication No. 2020-126917

In the solenoid device described in Patent Document 1, the entire inner peripheral surface of the core is formed straight. In other words, the distance from the plunger housed in the core is kept constant on the mouth side and the bottom side of the inner circumference of the core. Therefore, the magnetic flow from the outer circumference of the plunger to the inner circumference of the core remains constant throughout the entire stroke of the plunger.

Requirements for a solenoid device vary depending on the use of the solenoid device. As an example, near the end of movement position where the plunger is closest to the bottom of the core, it may be required to increase the suction force in the direction where the plunger approaches the bottom of the core. However, it is difficult to satisfy the above requirements with a solenoid device in which the inner peripheral portion of the core is machined straight.

An object of the present invention is to provide a solenoid device that increases the suction force in the direction in which the plunger approaches the bottom of the core near the end position of the plunger.

A first exemplary invention of the present application includes a cylindrical bobbin having a through hole passing through the bobbin along the axial direction, a coil wound around the outer circumference of the bobbin, and a magnetic material. The core includes a cylindrical core that is arranged and has a bottom on one side in the axial direction, and a columnar or cylindrical plunger that is arranged inside the core and moves toward the bottom of the core by magnetic force accompanying energization of the coil. The inner circumferential surface of the solenoid device has a tapered inclined surface whose inner diameter gradually decreases from the bottom on one axial side toward the other axial side.

According to the first exemplary embodiment of the present application, it is possible to provide a solenoid device in which the suction force in the direction in which the plunger approaches the bottom of the core is strengthened near the end position of the plunger's movement.

FIG. 1 is a sectional view of a solenoid device according to an embodiment of the present invention. FIG. 2A is a partial cross-sectional view showing the state of the solenoid device shown in FIG. 1 before the plunger moves. FIG. 2B is a partial cross-sectional view showing the state of the solenoid device shown in FIG. 1 after the plunger has moved. FIG. 3A is a partial cross-sectional view showing the flow of magnetic flux when a non-tapered front core is used. FIG. 3B is a partial cross-sectional view showing the flow of magnetic flux when a tapered front core is used. FIG. 4 is a diagram showing the suction force characteristics when a non-tapered front core is used and the suction force characteristics when a tapered front core is used. FIG. 5 is a sectional view showing a modification of the solenoid device shown in FIG. 1. FIG. 6 is a sectional view showing another modification of the solenoid device shown in FIG.

DESCRIPTION OF THE PREFERRED EMBODIMENTS A solenoid device according to an embodiment of the present invention will be described below with reference to the drawings.
Note that in the following, for convenience of explanation, three mutually orthogonal axes are set as an X axis, a Y axis, and a Z axis. As an example, an XY plane including an X axis and a Y axis is horizontal, and a Z axis is vertical. In this specification, terms expressing positional relationships such as vertical direction, horizontal direction, upper side, and lower side are used simply to describe the relative positional relationship of each part. Therefore, the actual positional relationship of each part may be different from the positional relationship indicated by these terms. Furthermore, in this specification, the direction in which the plunger moves due to the magnetic force associated with the energization of the coil, that is, the bottom side of the core is referred to as "one axial side." Further, the opposite side to one axial side is referred to as "the other axial side."

The solenoid device 1 shown in FIG. 1 includes a bobbin 2, a coil 3, a core 4, a plunger 8, a pin 9, and a case 10.
Case 10 is a cylindrical member. The case 10 is made of a magnetic metal material such as iron, that is, a magnetic material.

A bobbin 2 is arranged inside the case 10. The bobbin 2 is a cylindrical member having a through hole extending parallel to the X axis. The inner diameter of the through hole is constant along the X-axis direction. The bobbin 2 is made of various resin materials such as polyester and polyimide.

A conductive coil 3 is wound around the outer periphery of the bobbin 2 . Further, a core 4 is arranged within the through hole of the bobbin 2. The core 4 is formed into a cylindrical shape as a whole. The core 4 has a front core 5 and a back core 6. The front core 5 is a first core member disposed on one side in the axial direction within the through hole of the bobbin 2 . The back core 6 is a second core member disposed on the other axial side within the through hole of the bobbin 2 . The front core 5 and the back core 6 are made of a magnetic metal material such as iron, that is, a magnetic material.

A magnetic gap portion 7 is provided between the front core 5 and the back core 6 to make it difficult for magnetism to flow in the X-axis direction. That is, the core 4 includes a front core 5 and a back core 6 adjacent to the front core 5 with the magnetic gap section 7 interposed therebetween. The magnetic gap portion 7 is made of, for example, a non-magnetic resin collar member. Therefore, the front core 5 and the back core 6 are magnetically separated in the X-axis direction due to the presence of the magnetic gap portion 7.

Note that the magnetic gap portion 7 is not limited to a configuration using a non-magnetic member. As an example, the front core 5 and the back core 6 may be formed of a single member, and an extremely thin constriction portion may be provided between the front core 5 and the back core 6 as the magnetic gap portion 7. As another example, the front core 5 and the back core 6 are formed from a single member, and a magnetic gap portion 7 formed by passing a large number of holes in the radial direction is provided between the front core 5 and the back core 6. You can. Alternatively, the front core 5 and the back core 6 may be simply separated spatially. Further, in the case where at least one surface of the front core 5 or the back core 6 is subjected to a non-magnetizing process, the front core 5 and the back core 6 may be arranged so as to be in contact with each other.

The front core 5 has a bottom portion 51 at one end in the axial direction. The bottom 51 of the front core 5 is provided with an opening 52 that passes through the bottom 51 of the front core 5 in the X-axis direction. The pin 9 is disposed such that it passes through an opening 52 provided in the bottom 51 of the front core 5, and one end in the axial direction protrudes from the case 10.

A plunger 8 is disposed inside the core 4, that is, inside the front core 5 and the back core 6, so as to be able to reciprocate along the X-axis direction. The plunger 8 may have a cylindrical shape with a cavity inside, or may have a cylindrical shape without a cavity inside. The plunger 8 is made of a magnetic metal material such as iron, that is, a magnetic material. The bobbin 2, core 4, and plunger 8 are arranged concentrically about a common axis O.

The plunger 8 as a whole has a straight shape whose outer diameter does not change along the X-axis direction. However, the plunger 8 is not required to have a completely straight shape, but only needs to have a constant outer diameter at least in a section facing a tapered inclined surface, which will be described later (see FIG. 2B). Further, the end portion of the plunger 8 on one side in the axial direction may be chamfered such as a C-face cut or an R-face cut. In other words, "the outer diameter of the section facing the tapered inclined surface is constant" does not exclude general processing performed on the end of the plunger.

The plunger 8 moves toward one side in the axial direction, that is, toward the bottom 51 of the front core 5, due to the magnetic force caused by the energization of the coil 3. When the coil 3 is de-energized, it moves toward the other side in the axial direction, that is, moves away from the bottom 51 of the front core 5 due to the action of a biasing member (not shown) such as a coil spring. This reciprocating motion of plunger 8 is transmitted to an external device (not shown) via pin 9.

Here, the inner circumferential surface of the core 4 has a tapered inclined surface whose inner diameter gradually decreases from the bottom on one axial side toward the other axial side. That is, the inner diameter of the inner circumferential surface of the core 4 is maximum at the bottom on one axial side, and gradually decreases toward the other axial side until it becomes approximately the same as the outer diameter of the plunger 8. In this embodiment, a tapered inclined surface 55 is provided on the inner peripheral surface of the front core 5. The tapered inclined surface 55 will be described below with reference to FIGS. 2A and 2B.

FIG. 2A shows the state of the plunger 8 before it is moved. Moreover, FIG. 2B shows the state after the plunger 8 has been moved. In FIGS. 2A and 2B, "P1" is the movement start position of the bottom surface 81 of the plunger 8 in the X-axis direction, and is also referred to as the stroke start point. Moreover, "P2" is the movement end position of the bottom surface 81 of the plunger 8 in the X-axis direction, and is also referred to as the stroke end point. In FIGS. 2A and 2B, the movement start position P1 is aligned with the upper end of the inner surface of the front core 5, and the movement end position P2 is aligned with the lower end of the inner surface of the front core 5.

The tapered inclined surface 55 is provided, for example, in a section of the inner peripheral surface of the front core 5 from the movement start position P1 to the movement end position P2. In this embodiment, since the upper and lower ends of the inner peripheral surface of the front core 5 coincide with the movement start position P1 and the movement end position P2, the entire inner peripheral surface of the front core 5 is formed into a tapered inclined surface 55. There is. On the other hand, the entire inner surface of the back core 6 is formed straight.

The tapered inclined surface 55 can be defined by a length L along the X-axis direction and a depth D along the direction perpendicular to the X-axis. The length L of the tapered inclined surface 55 is the distance between the upper end and the lower end of the tapered inclined surface 55. The depth D of the tapered inclined surface 55 is the difference between the inner diameter φ1 at the upper end of the tapered inclined surface 55 and the inner diameter φ2 at the lower end of the tapered inclined surface 55. Further, the inclination angle θ of the tapered inclined surface 55 is determined by the length L and the depth D. That is, θ=tan ⁻¹ (D/L). The ratio of length L to depth D (L:D) is preferably in the range of (2:3) to (2:4). That is, it is desirable that L/D=1.5 to 2. Further, the inclination angle θ is preferably in the range of 0.25° to 5°.

By providing the tapered inclined surface 55 as described above on the front core 5, the amount of magnetic flux flowing from the bottom surface 81 of the plunger 8 to the bottom portion 51 of the front core 5 is increased when the plunger 8 approaches the movement end position P2. be able to. FIG. 3A shows the flow of magnetic flux when a front core 5' without a taper is used as a comparative example. The entire inner surface of the non-tapered front core 5' is formed straight. FIG. 3B shows the flow of magnetic flux when a tapered front core 5 is used. The tapered front core 5 has the tapered inclined surface 55 as described above.

In FIGS. 3A and 3B, the flow of magnetic flux is represented by black arrows. Here, it is assumed that the amount of magnetic flux flowing through the plunger 8 as the coil 3 is energized is 6 g. When a front core 5' without a taper is used, as shown in FIG. A magnetic flux of 2 g flows toward the bottom of the core 5'. On the other hand, when a tapered front core 5 is used, as shown in FIG. 3B, a magnetic flux of 2 g flows from the outer peripheral surface of the plunger 8 toward the inner peripheral surface of the front core 5, and A magnetic flux of 4 g flows from the front core 5 toward the bottom.

That is, by using the tapered front core 5, the distance between the outer peripheral surface of the plunger 8 and the inner peripheral surface of the front core 5 gradually increases as the plunger 8 approaches the movement end position P2. Therefore, the amount of magnetic flux flowing from the outer peripheral surface of the plunger 8 toward the inner peripheral surface of the front core 5 decreases, and as a result, the amount of magnetic flux flowing from the bottom surface of the plunger 8 toward the bottom of the front core 5 decreases. This will result in an increase in

For comparison, FIG. 4 shows the suction force characteristic C1 when a non-tapered front core 5' is used and the suction force characteristic C2 when a tapered front core 5 is used. In the graph shown in FIG. 4, the horizontal axis is the stroke position (mm), and the vertical axis is the suction force (N).

According to FIG. 4, in the stroke position range of 0 to 2.6 (mm), the non-tapered front core 5' has a stronger suction force than the tapered front core 5. On the other hand, in the stroke position range of 2.6 to 3.0 (mm), the tapered front core 5 has a stronger suction force than the non-tapered front core 5'.

As described above, the solenoid device 1 shown in FIG. 1 is made of a cylindrical bobbin 2 having a through hole extending in the axial direction, a coil 3 wound around the outer circumference of the bobbin 2, and a magnetic material. , a cylindrical core 4 disposed in the through hole of the bobbin 3 and having a bottom on one side in the axial direction; The inner circumferential surface of the core 4 has a tapered slope whose inner diameter gradually decreases from the bottom on one axial side toward the other axial side.

In this way, by using a core with a tapered inclined surface on the inner peripheral surface, it is possible to relatively increase the amount of magnetic flux flowing from the bottom of the plunger toward the bottom of the core near the end position of the plunger. can. As a result, the suction force in the direction in which the plunger approaches the bottom of the core is strengthened. Therefore, it is possible to increase the resistance to a force in a direction opposite to the attraction force, which is transmitted via the pin from an external device due to disturbance or the like.

Further, the core 4 includes a front core 5 disposed on one side in the axial direction, and a back core 6 disposed on the other side in the axial direction adjacent to the front core 5 via a magnetic gap part 7. A tapered inclined surface 55 is provided on the inner circumferential surface of 5. That is, in the magnetic circuit formed by the cores including the front core and the back core, a tapered inclined surface is provided on the front core side into which the magnetic flux from the plunger flows. Therefore, the amount of magnetic flux flowing from the bottom of the plunger toward the bottom of the core can be efficiently increased.

Further, the entire inner peripheral surface of the front core 5 is a tapered inclined surface 55. Therefore, while gradually reducing the amount of magnetic flux flowing from the outer circumferential surface of the plunger toward the inner circumferential surface of the front core, the amount of magnetic flux flowing from the bottom surface of the plunger toward the bottom of the core is relatively increased throughout the entire area of the front core. can be done.

Here, in the above description, the entire inner circumferential surface of the front core 5 is made into the tapered inclined surface 55, but this is only an example. For example, as shown in a modified example in FIG. 5, the tapered inclined surface 56 may be provided only in a portion of the bottom surface side of the inner circumferential surface of the front core 5. Further, as shown in another modification example in FIG. 6, the entire inner circumferential surface of the front core 5 is made into a tapered inclined surface 57, and a part of the inner circumferential surface of the back core 6 on the bottom side is also tapered. A shaped inclined surface 65 may be provided. In other words, any tapered inclined surface that meets the requirements of the solenoid device can be provided on the inner peripheral surface of the core of the solenoid device.

Furthermore, in the above description, the bobbin 2, core 4, and plunger 8 have a cylindrical or columnar shape as a whole, but are not limited to this. For example, the bobbin 2, core 4, and plunger 8 may have a prismatic tube shape or a prismatic shape.

Although the solenoid device according to the present invention has been described above with reference to the drawings, the present invention is not limited thereto, and each part constituting the solenoid device may have any configuration that can perform the same function. can be replaced with Moreover, arbitrary components may be added to the solenoid device.

DESCRIPTION OF SYMBOLS 1... Solenoid device, 2... Bobbin, 3... Coil, 4... Core, 5... Front core, 6... Back core, 7... Magnetic gap part, 8... Plunger, 9... Pin 9, 10... Case, 51... Bottom, 52...Opening, 55, 56, 57, 65: Tapered inclined surface, O...Axis, P1...Movement start position, P2...Movement end position, L...Length, D...Depth, φ1, φ2...Inner diameter, θ…Inclination angle

Claims (4)

a cylindrical bobbin having a through hole extending along the axial direction;
a coil wound around the outer periphery of the bobbin;
a cylindrical core made of a magnetic material, disposed in the through hole of the bobbin, and having a bottom on one side in the axial direction;
a columnar or cylindrical plunger that is disposed inside the core and moves toward the bottom of the core by magnetic force accompanying energization of the coil;
In the solenoid device, the inner circumferential surface of the core has a tapered inclined surface whose inner diameter gradually decreases from the bottom portion on one axial side toward the other axial side. The core includes a first core member disposed on one axial side of the through hole, and a first core member disposed on the other axial side of the through hole adjacent to the first core member via a magnetic gap. a second core member;
The solenoid device according to claim 1, wherein the tapered inclined surface is provided on an inner circumferential surface of the first core member. The solenoid device according to claim 2, wherein the first core member has an entire inner circumferential surface formed as the tapered inclined surface. The solenoid device according to any one of claims 1 to 3, wherein the plunger has a constant outer diameter in a section facing the tapered inclined surface.