CN217307521U - Electric actuator - Google Patents

Abstract

An electric actuator having: a movable member having an iron core body made of a magnetic body and moving in an axial direction along a central axis; a coil located radially outside the core body, surrounding the core body; a magnetic body case that houses the core body and the coil therein; and a magnet housed inside the case, the magnet being located radially inside or radially outside the coil. The housing has: a peripheral wall portion located radially outside the coil and surrounding the coil; a 1 st axial wall portion located on one axial side of the coil; and a 2 nd axial wall portion located on the other axial side of the coil. The 1 st axial wall portion has a 1 st core portion located on one axial side of the core body. The 2 nd axial wall portion has a 2 nd core portion located on the other axial side of the core body. The area of the portion of the 1 st core portion facing the other axial side that overlaps with the core body as viewed in the axial direction is larger than the area of the portion of the 2 nd core portion facing the one axial side that overlaps with the core body as viewed in the axial direction.

Description

Electric actuator

Technical Field

The utility model relates to an electric actuator.

Background

For example, patent document 1 describes a solenoid including two cylindrical bobbins to which excitation coils are attached, respectively, and a permanent magnet sandwiched between the two cylindrical bobbins.

Patent document 1: japanese examined patent publication (Kokoku) No. 8-2968

In the solenoid as described above, since the two cylindrical bobbins each having the excitation coil attached thereto are arranged in line in the axial direction, there is a problem in that the axial dimension of the solenoid is increased.

SUMMERY OF THE UTILITY MODEL

In view of the above, an object of the present invention is to provide an electric actuator having a structure that can be miniaturized in an axial direction.

One embodiment of the electric actuator of the present invention includes: a movable piece having an iron core body made of a magnetic body, the movable piece being movable in an axial direction along a center axis; a coil located radially outside the core body, surrounding the core body; a magnetic body case that houses the core body and the coil therein; and a magnet housed inside the case, the magnet being positioned radially inside the coil or radially outside the coil. The housing has: a peripheral wall portion located radially outward of the coil and surrounding the coil; a 1 st axial wall portion located on one axial side of the coil; and a 2 nd axial wall portion located on the other axial side of the coil. The 1 st axial wall portion has a 1 st core portion located on one axial side of the core body. The 2 nd axial wall portion has a 2 nd core portion located on the other axial side of the core body. An area of a portion of the 1 st core portion facing the other axial side that overlaps with the core body as viewed in the axial direction is larger than an area of a portion of the 2 nd core portion facing the one axial side that overlaps with the core body as viewed in the axial direction.

In the electric actuator according to the above aspect, the 1 st core portion includes a 1 st receiving portion capable of receiving therein an end portion of the core body on one side in the axial direction, the 2 nd core portion includes a 2 nd receiving portion capable of receiving therein an end portion of the core body on the other side in the axial direction, and an area of an inner surface of the 1 st receiving portion is larger than an area of an inner surface of the 2 nd receiving portion.

In the electric actuator of the above aspect, the 1 st housing portion includes: a 1 st bottom wall portion located on one axial side of the core body; and a 1 st cylindrical wall portion protruding from a radial outer peripheral edge portion of the 1 st bottom wall portion to the other axial side, the 2 nd accommodating portion including: a 2 nd bottom wall portion located on the other axial side of the core body; and a 2 nd cylindrical wall portion protruding from a radially outer peripheral edge portion of the 2 nd bottom wall portion toward one axial side.

In the electric actuator according to the above aspect, at least a part of the 1 st cylindrical wall portion and at least a part of the 2 nd cylindrical wall portion are located radially inward of the coil.

In the electric actuator of the above-described aspect, the 1 st core portion has a volume larger than that of the 2 nd core portion.

In the electric actuator of the above aspect, the dimension in the radial direction of the 1 st core portion is larger than the dimension in the radial direction of the 2 nd core portion.

In the electric actuator of the above aspect, the magnet is positioned between the 1 st axial wall portion and the 2 nd axial wall portion in the axial direction, and is arranged to be separated from both the 1 st axial wall portion and the 2 nd axial wall portion in the axial direction.

In the electric actuator of the above aspect, an axial position of the central portion in the axial direction of the magnet is the same as an axial position of the central portion in the axial direction between the portion of the housing on one side in the axial direction of the core body and the portion of the housing on the other side in the axial direction of the core body.

In the electric actuator according to the above aspect, the magnet is located radially inward of the coil.

According to an aspect of the present invention, the electric actuator can be axially miniaturized.

Drawings

Fig. 1 is a sectional view showing an electric actuator according to an embodiment.

Fig. 2 is a sectional view showing an electric actuator and an arm coupled to the electric actuator according to an embodiment.

Fig. 3 is a cross-sectional view showing a part of an electric actuator according to an embodiment, and is a view showing a state in which a movable element is positioned at the uppermost side.

Fig. 4 is a cross-sectional view showing a part of an electric actuator according to an embodiment, and is a view showing a state in which a movable element moves from an upper side to a lower side.

Fig. 5 is a sectional view showing a part of an electric actuator according to an embodiment, and is a view showing a state where a movable element is positioned at the lowermost side.

Fig. 6 is a cross-sectional view showing a part of an electric actuator according to an embodiment, and is a view showing a state in which a movable element moves from a lower side to an upper side.

Description of the reference symbols

10: a housing; 10 a: 1 st axial wall portion; 10 b: a 2 nd axial wall portion; 11 b: a peripheral wall portion; 21: 1 st iron core part; 21 b: a 1 st receiving part; 21 c: 1 st bottom wall part; 21 d: a 1 st cylindrical wall portion; 21p, 22 p: an inner surface; 22: a 2 nd iron core; 22 b: a 2 nd accommodating part; 22 c: the 2 nd bottom wall portion; 22 d: a 2 nd cylindrical wall portion; 40: a coil; 50: a magnet; 70: a movable member; 72: an iron core body; 100: an electric actuator; j: a central axis.

Detailed Description

The electric actuator 100 of the present embodiment shown in fig. 1 is an electric actuator mounted on a vehicle. More specifically, the electric actuator 100 is, for example, an electric actuator mounted in a parking-by-wire type actuator device that is driven based on a shift operation by a vehicle driver.

In each figure, a central axis J of the electric actuator 100 is shown. The central axis J is an imaginary axis. In the following description, the direction in which the central axis J extends, that is, the axial direction of the central axis J is simply referred to as the "axial direction", the radial direction about the central axis J is simply referred to as the "radial direction", and the circumferential direction about the central axis J is simply referred to as the "circumferential direction". In each figure, a Z-axis parallel to the axial direction is shown. In the following description, a side (+ Z side) of the axial direction, which is pointed by an arrow of the Z axis, is referred to as an "upper side", and a side (-Z side) of the axial direction, which is opposite to the side pointed by the arrow of the Z axis, is referred to as a "lower side". In the present embodiment, the upper side corresponds to the "one axial side", and the lower side corresponds to the "other axial side". The upper side and the lower side are names for explaining the arrangement of the respective parts, and the actual arrangement may be an arrangement other than the arrangement shown by these names.

As shown in fig. 1, an electric actuator 100 of the present embodiment includes a case 10, a bobbin 30, a coil 40, a cover 41, a magnet 50, a guide member 60, a spacer 61, a mover 70, and an elastic member 80. The electric actuator 100 can switch between a locked state in which the gear of the vehicle is parked and an unlocked state in which the gear of the vehicle is not parked by moving the movable element 70 in the axial direction. The case where the gear of the vehicle is not in the parking state includes, for example, the case where the gear of the vehicle is in the drive, neutral, reverse, or the like.

The movable member 70 is movable in the axial direction along the center axis J. The movable element 70 includes a shaft 71 disposed along a center axis J extending in the axial direction, and a core body 72 made of a magnetic material fixed to the shaft 71. The shaft 71 is cylindrical and extends in the axial direction around the center axis J. In the present embodiment, the outer diameter of the shaft 71 is the same as a whole in the axial direction. The shaft 71 is made of a non-magnetic material.

In the present specification, the "magnetic material" includes a ferromagnetic material. In the present specification, the term "nonmagnetic substance" refers to a substance other than a ferromagnetic substance and includes a diamagnetic substance and a paramagnetic substance. The non-magnetic body has a property of being harder for magnetic flux to pass through than the magnetic body.

As shown in fig. 2, one end of the arm a extending in one direction is rotatably coupled to an upper end of the shaft 71. The arm a is rotatable about a rotation axis R provided at a middle portion of the arm a. The rotation axis R is an imaginary axis extending in a direction perpendicular to the central axis J. The arm a is connected to, for example, a shift lever of a vehicle.

In the present embodiment, the core body 72 is a cylindrical shape extending in the axial direction and opened at both sides in the axial direction. More specifically, the core body 72 is a cylindrical shape centered on the central axis J. A shaft 71 axially penetrates the radially inner side of the core body 72. The inner peripheral surface of the core body 72 is fixed to the outer peripheral surface of the shaft 71. As shown in fig. 1, the core body 72 has a core center portion 72a, a core upper portion 72b, and a core lower portion 72 c. The core center portion 72a is a portion of the core body 72 that is located at the axial center. The outer diameter of the core center portion 72a is the same in the entire axial direction.

The core upper portion 72b is a portion of the core body 72 that is continuous with the upper side of the core central portion 72 a. The upper end of the core upper portion 72b is the upper end of the core body 72. The core upper portion 72b has an outer diameter smaller than that of the core central portion 72 a. The core upper portion 72b has an outer diameter that decreases as it goes upward away from the core central portion 72 a. The outer peripheral surface of the core upper portion 72b is a tapered surface whose outer diameter decreases from the lower side toward the upper side.

The core lower portion 72c is a portion of the core body 72 that is connected to the lower side of the core central portion 72 a. The end portion on the lower side of the core lower portion 72c is the end portion on the lower side of the core body 72. The core lower portion 72c has an outer diameter smaller than that of the core central portion 72 a. The core lower portion 72c has an outer diameter that decreases as it goes downward from the core central portion 72 a. The outer peripheral surface of the core lower portion 72c is a tapered surface whose outer diameter decreases from the upper side toward the lower side. The axial dimension of the core upper portion 72b and the axial dimension of the core lower portion 72c are smaller than the axial dimension of the core central portion 72 a. The axial dimension of the core upper portion 72b and the axial dimension of the core lower portion 72c are, for example, the same as each other.

The case 10 accommodates therein the bobbin 30, the coil 40, the magnet 50, the guide member 60, the spacer 61, a part of the shaft 71, and the core body 72. The housing 10 is made of a magnetic body. The housing 10 includes a cylindrical member 11, a cover member 12, a 1 st core portion 21, and a 2 nd core portion 22. In the present embodiment, the tubular member 11, the lid member 12, the 1 st core portion 21, and the 2 nd core portion 22 are separate members made of a magnetic material.

The tubular member 11 is tubular with an upward opening. In the present embodiment, the tubular member 11 is a cylindrical member having the center axis J as the center. The tubular member 11 has an annular portion 11a surrounding the central axis J and a peripheral wall portion 11b extending upward from a radially outer peripheral edge portion of the annular portion 11 a. That is, the housing 10 has an annular portion 11a and a peripheral wall portion 11 b. In the present embodiment, the annular portion 11a is annular with the center axis J as the center. The annular portion 11a is plate-shaped with its plate surface facing in the axial direction. In the present embodiment, the peripheral wall portion 11b is cylindrical with the center axis J as the center. The peripheral wall portion 11b is located radially outward of the coil 40. The peripheral wall portion 11b surrounds the coil 40.

The lid member 12 is annular surrounding the central axis J. In the present embodiment, the lid member 12 is annular with the center axis J as the center. The lid member 12 is a plate-like member having a plate surface facing in the axial direction. The lid member 12 is fixed to an upper end of the cylindrical member 11. The lid member 12 protrudes radially inward from an upper end of the tubular member 11. The lid member 12 closes a part of the upper opening of the cylindrical member 11. The lid member 12 is fixed to the tubular member 11 by a plurality of pressure-bonding portions 11c provided at an upper end of the tubular member 11, for example. The crimping portion 11c is a portion to be crimped.

The 1 st core portion 21 is fixed to the radially inner side of the annular cover member 12. The 1 st core portion 21 is located on the upper side of the core body 72. The 1 st core portion 21 is provided with a 1 st through hole 21e that penetrates the 1 st core portion 21 in the axial direction. In the present embodiment, the 1 st through hole 21e is a circular hole having the center axis J as the center. The shaft 71 axially passes through the 1 st through hole 21 e. The shaft 71 is fitted into the 1 st through hole 21e with a gap, for example. In the present embodiment, the 1 st through hole 21e supports the shaft 71 so as to be movable in the axial direction. The movable element 70 moves in the axial direction while a part of the outer peripheral surface of the shaft 71 is in contact with the inner peripheral surface of the 1 st through hole 21e, for example.

The 1 st iron core part 21 has a 1 st base part 21a, a 1 st receiving part 21b, and a pressure-bonding part 21 m. The 1 st base portion 21a is fitted to the inside in the radial direction of the lid member 12. The 1 st base 21a is annular with the center axis J as the center. The 1 st receiving portion 21b is connected to the lower side of the 1 st base portion 21 a. The 1 st accommodation portion 21b is located radially inward of the peripheral wall portion 11 b. The 1 st accommodation portion 21b is fitted radially inward of the upper end of the bobbin 30. The 1 st receiving portion 21b can receive an upper end portion of the core body 72 therein. The 1 st accommodation portion 21b is open downward. The 1 st housing portion 21b has a 1 st bottom wall portion 21c and a 1 st cylindrical wall portion 21 d.

The 1 st bottom wall portion 21c is a portion connected to the lower side of the 1 st base portion 21 a. The 1 st bottom wall portion 21c is located on the upper side of the core body 72. In the present embodiment, the 1 st bottom wall portion 21c is annular with the center axis J as the center. The outer diameter of the 1 st bottom wall portion 21c is larger than the outer diameter of the 1 st base portion 21 a. The 1 st bottom wall portion 21c protrudes radially outward from the 1 st base portion 21 a. The portion of the 1 st bottom wall portion 21c located radially outward of the 1 st base portion 21a contacts the lower surface of the lid member 12. The 1 st bottom wall portion 21c has a 1 st bottom surface 21k facing downward. The 1 st bottom surface 21k is annular and surrounds the opening on the lower side of the 1 st through hole 21e around the central axis J. The 1 st bottom surface 21k is a flat surface perpendicular to the axial direction.

The 1 st cylindrical wall portion 21d protrudes downward from the radially outer peripheral edge portion of the 1 st bottom wall portion 21 c. In the present embodiment, the 1 st cylindrical wall portion 21d is a cylindrical shape having a center axis J as a center and opening downward. At least a part of the 1 st cylindrical wall portion 21d is located radially inward of the coil 40. In the present embodiment, the entire 1 st cylindrical wall portion 21d is located radially inward of the upper end portion of the coil 40. An outer stepped portion 21r having a stepped surface 21f facing downward is provided on a lower portion of the outer peripheral surface of the 1 st cylindrical wall portion 21 d. The step surface 21f is annular with the center axis J as the center. The step surface 21f is a flat surface perpendicular to the axial direction. The portion of the outer peripheral surface of the 1 st cylindrical wall portion 21d located above the outer stepped portion 21r is cylindrical and has a uniform outer diameter in the entire axial direction.

An inner stepped portion 21s having a stepped surface 21g facing downward is provided at a lower portion of the inner peripheral surface of the 1 st cylindrical wall portion 21 d. The step surface 21g is annular with the center axis J as the center. The step surface 21g is a flat surface perpendicular to the axial direction. The inner step portion 21s is located above the outer step portion 21 r. The inner peripheral surface portion 21i of the inner peripheral surface of the 1 st cylindrical wall portion 21d, which is located below the inner stepped portion 21s, is cylindrical and has a uniform inner diameter in the entire axial direction. An inner peripheral surface portion 21j of the inner peripheral surface of the 1 st cylindrical wall portion 21d on the upper side of the inner stepped portion 21s is a tapered surface whose inner diameter becomes smaller from the lower side toward the upper side. The inner peripheral surface portion 21j has an inner diameter smaller than that of the inner peripheral surface portion 21 i. The inner peripheral surface portion 21j is positioned radially inward of the inner peripheral surface portion 21 i. The axial dimension of the inner peripheral surface portion 21j is larger than the axial dimension of the inner peripheral surface portion 21 i.

By providing the outer step portion 21r and the inner step portion 21s, the 1 st fitting portion 21h is provided at the end portion below the 1 st cylindrical wall portion 21 d. That is, the 1 st core portion 21 has the 1 st fitting portion 21 h. The inner peripheral surface of the 1 st fitting portion 21h is an inner peripheral surface portion 21 i. The outer peripheral surface of the 1 st fitting portion 21h is a portion of the outer peripheral surface of the 1 st cylindrical wall portion 21d that is located below the outer stepped portion 21 r. The upper portion of the outer peripheral surface of the 1 st fitting portion 21h is cylindrical and has a uniform outer diameter over the entire axial direction. The lower portion of the outer peripheral surface of the 1 st fitting portion 21h is a tapered surface whose outer diameter decreases from the upper side toward the lower side.

In the present embodiment, the inner surface 21p of the 1 st accommodation portion 21b is constituted by the inner peripheral surface portion 21i, the step surface 21g of the inner step portion 21s, the inner peripheral surface portion 21j, and the 1 st bottom surface 21 k. The upper end of the inner peripheral surface portion 21i and the lower end of the inner peripheral surface portion 21j are connected by a stepped surface 21 g. The upper end of the inner peripheral surface portion 21j is connected to the radially outer end of the 1 st bottom surface 21 k. In the present embodiment, the inner peripheral surface portion 21j and the 1 st bottom surface 21k are portions that overlap the core body 72 when viewed in the axial direction, of the surfaces facing downward of the 1 st core portion 21.

The crimping portion 21m is a portion to be crimped. The pressure-bonding section 21m protrudes radially outward from a radially outer peripheral edge of an upper end of the 1 st base 21 a. The pressure contact part 21m is in contact with the upper surface of the cover member 12. The radially inner peripheral portion of the lid member 12 is sandwiched by the crimping portion 21m and the 1 st bottom wall portion 21c in the axial direction. Thereby, the 1 st core portion 21 is fixed to the cover member 12.

The 2 nd core portion 22 is fixed radially inside the annular portion 11 a. The 2 nd core portion 22 is located on the lower side of the core body 72. The 2 nd core part 22 is provided with a 2 nd through hole 22e that penetrates the 2 nd core part 22 in the axial direction. In the present embodiment, the 2 nd through hole 22e is a circular hole centered on the central axis J. The shaft 71 axially passes through the 2 nd through hole 22 e. The outer peripheral surface of the portion of the shaft 71 that passes through the 2 nd through hole 22e is disposed away from the inner peripheral surface of the 2 nd through hole 22e toward the inside in the radial direction. In the present embodiment, the 2 nd through hole 22e does not support the shaft 71.

In the present embodiment, the inner diameter of the 2 nd through hole 22e is larger than the inner diameter of the 1 st through hole 21 e. Here, as described above, in the present embodiment, the outer diameter of the shaft 71 is the same in the entire axial direction. Therefore, in the present embodiment, the difference between the inner diameter of the 2 nd through hole 22e and the outer diameter of the portion of the shaft 71 that passes through the 2 nd through hole 22e is larger than the difference between the inner diameter of the 1 st through hole 21e and the outer diameter of the portion of the shaft 71 that passes through the 1 st through hole 21 e. The radial gap between the inner peripheral surface of the 2 nd through-hole 22e and the outer peripheral surface of the portion of the shaft 71 that passes through the 2 nd through-hole 22e is larger than the radial gap between the inner peripheral surface of the 1 st through-hole 21e and the outer peripheral surface of the portion of the shaft 71 that passes through the 1 st through-hole 21 e.

The 2 nd core part 22 has a 2 nd base part 22a, a 2 nd housing part 22b, and a crimping part 22 m. The 2 nd base portion 22a is fitted radially inside the annular portion 11 a. The 2 nd base 22a is annular with the center axis J as the center.

The 2 nd receiving portion 22b is connected to an upper side of the 2 nd base portion 22 a. The 2 nd accommodating portion 22b is located radially inward of the peripheral wall portion 11 b. The 2 nd accommodating portion 22b is inserted radially inward of the lower end of the bobbin 30. A gap is provided between the outer peripheral surface of the 2 nd accommodating portion 22b and the inner peripheral surface of the bobbin 30 in the radial direction. The 2 nd receiving portion 22b can receive the lower end portion of the core body 72 therein. The 2 nd accommodating portion 22b is open to the upper side. In the present embodiment, the outer diameter of the 2 nd housing portion 22b is smaller than the outer diameter of the 1 st housing portion 21 b. In the present embodiment, the axial dimension of the 2 nd housing portion 22b is smaller than the axial dimension of the 1 st housing portion 21 b. The 2 nd housing portion 22b has a 2 nd bottom wall portion 22c and a 2 nd cylindrical wall portion 22 d.

The 2 nd bottom wall portion 22c is a portion connected to the upper side of the 2 nd base portion 22 a. The 2 nd bottom wall portion 22c is located on the lower side of the core body 72. In the present embodiment, the 2 nd bottom wall portion 22c is annular with the center axis J as the center. The outer diameter of the 2 nd bottom wall portion 22c is larger than the outer diameter of the 2 nd base portion 22 a. The 2 nd bottom wall portion 22c protrudes radially outward from the 2 nd base portion 22 a. The portion of the 2 nd bottom wall portion 22c radially outward of the 2 nd base portion 22a contacts the upper surface of the annular portion 11 a. The 2 nd bottom wall portion 22c has a 2 nd bottom surface 22k facing upward. The 2 nd bottom surface 22k is annular surrounding the opening on the upper side of the 2 nd through hole 22e with the center axis J as the center. The 2 nd bottom surface 22k is a flat surface perpendicular to the axial direction.

The 2 nd cylindrical wall portion 22d protrudes upward from the radially outer peripheral edge portion of the 2 nd bottom wall portion 22 c. In the present embodiment, the 2 nd cylindrical wall portion 22d is a cylindrical shape having the center axis J as a center and opening to the upper side. At least a part of the 2 nd cylindrical wall portion 22d is located radially inward of the coil 40. In the present embodiment, the entire 2 nd cylindrical wall portion 22d is located radially inward of the lower end portion of the coil 40. An outer stepped portion 22r having a stepped surface 22f facing upward is provided at an upper portion of the outer peripheral surface of the 2 nd cylindrical wall portion 22 d. The step surface 22f is annular with the center axis J as the center. The step surface 22f is a flat surface perpendicular to the axial direction. The inner peripheral surface 22j of the 2 nd cylindrical wall portion 22d is a tapered surface whose inner diameter decreases from the upper side toward the lower side. The axial dimension of the inner peripheral surface 22j is smaller than the axial dimension of the inner peripheral surface portion 21 j.

By providing the outer stepped portion 22r, the 2 nd fitting portion 22h is provided at the upper end of the 2 nd cylindrical wall portion 22 d. That is, the 2 nd core part 22 has the 2 nd fitting part 22 h. The inner peripheral surface of the 2 nd fitting portion 22h is an upper portion of the inner peripheral surface 22 j. The outer peripheral surface of the 2 nd fitting portion 22h is a portion of the outer peripheral surface of the 2 nd cylindrical wall portion 22d which is located above the outer stepped portion 22 r. The outer peripheral surface of the 2 nd fitting portion 22h is cylindrical with a uniform outer diameter in the entire axial direction. The outer peripheral surface of the 2 nd fitting portion 22h is positioned radially inward of the inner peripheral surface 21i, which is the inner peripheral surface of the 1 st fitting portion 21 h. That is, the outer diameter of the 2 nd fitting part 22h is smaller than the inner diameter of the 1 st fitting part 21 h.

In the present embodiment, the inner surface 22p of the 2 nd accommodating portion 22b is constituted by the inner peripheral surface 22j and the 2 nd bottom surface 22 k. The lower end of the inner peripheral surface 22j is connected to the radially outer end of the 2 nd bottom surface 22 k. In the present embodiment, the inner surface 22p is a portion of the upper surface of the 2 nd core portion 22 that overlaps the core body 72 when viewed in the axial direction. The area of the inner peripheral surface 22j is smaller than the area of the inner peripheral surface portion 21 j. The area of the 2 nd bottom surface 22k is smaller than that of the 1 st bottom surface 21 k. Therefore, the total area of the inner surface 22p is smaller than the total area of the inner peripheral surface portion 21j of the 1 st core portion 21 and the area of the 1 st bottom surface 21 k. That is, the area of the portion overlapping with the core body 72 when viewed in the axial direction in the surface facing the lower side of the 1 st core portion 21 is larger than the area of the portion overlapping with the core body 72 when viewed in the axial direction in the surface facing the upper side of the 2 nd core portion 22. In the present embodiment, the area of the inner surface 21p of the 1 st housing part 21b is larger than the area of the inner surface 22p of the 2 nd housing part 22 b.

The crimp portion 22m is a portion to be crimped. The pressure contact portion 22m protrudes radially outward from a radially outer peripheral edge portion of a lower end of the 2 nd base portion 22 a. The pressure contact portion 22m contacts the lower surface of the annular portion 11 a. The radially inner peripheral portion of the annular portion 11a is sandwiched by the crimping portion 22m and the 2 nd bottom wall portion 22c in the axial direction. Thereby, the 2 nd core part 22 is fixed to the annular part 11 a.

In the present embodiment, the radial dimension of the 1 st iron core portion 21 is larger than the radial dimension of the 2 nd iron core portion 22. The radial dimension of the 1 st housing portion 21b is larger than the radial dimension of the 2 nd housing portion 22 b. The 1 st accommodation portion 21b has an axial dimension larger than that of the 2 nd accommodation portion 22 b. In the present embodiment, the volume of the 1 st iron core portion 21 is larger than the volume of the 2 nd iron core portion 22. The volume of the 1 st receiving portion 21b is larger than that of the 2 nd receiving portion 22 b.

In the present embodiment, the 1 st axial wall portion 10a located above the coil 40 is configured by the cover member 12 and the 1 st iron core portion 21. In the present embodiment, the annular portion 11a and the 2 nd core portion 22 form the 2 nd axial wall portion 10b located below the coil 40. That is, in the present embodiment, the housing 10 includes the 1 st axial wall portion 10a having the 1 st core portion 21 and the 2 nd axial wall portion 10b having the 2 nd core portion 22. The 1 st axial wall portion 10a has a 1 st through hole 21e axially penetrating the 1 st axial wall portion 10 a. The 2 nd axial wall portion 10b has a 2 nd through hole 22e axially penetrating the 2 nd axial wall portion 10 b.

The bobbin 30 is located radially outward of the core body 72. The bobbin 30 has a cylindrical shape surrounding the core body 72. In the present embodiment, the bobbin 30 is a cylindrical shape having a center axis J as a center and opened at both axial sides. The bobbin 30 is located radially inward of the peripheral wall portion 11 b. The bobbin 30 is positioned between the annular portion 11a and the cover member 12 in the axial direction. The bobbin 30 is made of a non-magnetic body. The bobbin 30 is made of, for example, resin. The bobbin 30 has a bobbin body portion 31, an upper flange portion 32, and a lower flange portion 33.

The bobbin trunk 31 is cylindrical and opens on both sides in the axial direction with the center axis J as the center. The outer diameter of the bobbin trunk 31 is the same as a whole in the axial direction. The bobbin main body 31 has a 1 st portion 31a and a 2 nd portion 31b connected to a lower side of the 1 st portion 31 a. The upper end of the 1 st portion 31a is the upper end of the bobbin trunk 31. The end portion on the lower side of the 2 nd portion 31b is the end portion on the lower side of the bobbin trunk 31. The 1 st section 31a has a larger inner diameter than the 2 nd section 31 b. The outer diameter of the 1 st portion 31a and the outer diameter of the 2 nd portion 31b are the same as each other. The 1 st portion 31a has an axial dimension greater than that of the 2 nd portion 31 b. A step 34 having a step surface 34a facing upward is provided between the inner peripheral surface of the 1 st portion 31a and the inner peripheral surface of the 2 nd portion 31 b. That is, a step portion 34 having a step surface 34a facing upward is provided on the inner peripheral surface of the bobbin 30. In the present embodiment, the step surface 34a is a flat surface perpendicular to the axial direction. The step surface 34a is annular centered on the central axis J. The inner peripheral surface of the 2 nd portion 31b protrudes radially inward more than the inner peripheral surface of the 1 st portion 31 a.

The upper flange portion 32 protrudes radially outward from the upper end of the bobbin body portion 31. The upper flange portion 32 has an annular shape centered on the central axis J. The lower flange portion 33 protrudes radially outward from the lower end of the bobbin body portion 31. The lower flange portion 33 is annular with the center axis J as the center.

The bobbin 30 has a recess 35 recessed from a lower side end surface of the bobbin 30 toward an upper side. The recess 35 is open radially inward. The concave portion 35 is annular with the center axis J as the center. The recess 35 is provided in the lower flange portion 33. At least a part of the elastic member 80 is accommodated in the recess 35.

The axial dimension of the bobbin 30 is smaller than the axial distance between the upper surface of the annular portion 11a and the lower surface of the cover member 12. The upper end of the bobbin 30 is disposed opposite to the lower side of the lower surface of the cover member 12 with a gap therebetween. In the present embodiment, the upper surface of the upper flange 32 is disposed to face the lower surface of the lid member 12 with a gap therebetween. The lower end of the bobbin 30 is disposed opposite to the upper side of the upper surface of the annular portion 11a with a gap therebetween. In the present embodiment, the lower surface of the lower flange portion 33 is disposed to face the upper surface of the annular portion 11a with a gap therebetween.

The coil 40 is, for example, a solenoid formed by spirally winding a metal wire around the central axis J. The coil 40 is wound around the outer circumferential surface of the bobbin 30. More specifically, the coil 40 is wound around the outer peripheral surface of the bobbin main body 31. The coil 40 is cylindrical and extends in the axial direction around the central axis J. The coil 40 is located radially outward of the core body 72. The coil 40 surrounds the core body 72. The coil 40 is electrically connected to an external power supply not shown through a wiring member not shown.

The covering portion 41 is located radially outward of the bobbin 30 and the coil 40. The covering portion 41 is a cylindrical shape centered on the central axis J. The covering portion 41 covers the entire outer peripheral surface of the coil 40, the entire outer peripheral surface of the upper flange portion 32, and the entire outer peripheral surface of the lower flange portion 33. The cover 41 is fixed to the bobbin 30 and the coil 40. The covering portion 41 is fitted radially inward of the peripheral wall portion 11 b. The covering portion 41 is made of, for example, resin.

In the present embodiment, the magnet 50 is a cylindrical shape extending in the axial direction. More specifically, magnet 50 is a cylindrical shape having a center axis J as a center and being open on both sides in the axial direction. Although not shown, the magnet 50 is formed by aligning two semi-cylindrical magnets in the radial direction, for example. The magnets 50 have different magnetic poles in the radial direction. The magnetic poles on the radially inner side of the magnet 50 are different from the magnetic poles on the radially outer side of the magnet 50. In the present embodiment, the magnet 50 has a magnetic pole portion 50N of N-pole on the radially inner side. The magnet 50 has a magnetic pole portion 50S of an S pole on the radial outer side. Further, the radially inner side of the magnet 50 may be an S pole, and the radially outer side of the magnet 50 may be an N pole. In the present embodiment, the magnet 50 is a permanent magnet.

The magnet 50 is housed inside the case 10. Magnet 50 is axially located between axial wall 1a and axial wall 2 b. More specifically, the radially inner peripheral edge portion of the magnet 50 is located between the 1 st cylindrical wall portion 21d and the 2 nd cylindrical wall portion 22d in the axial direction. The magnet 50 has a radially outer peripheral edge portion located axially between the 1 st cylindrical wall portion 21d and the annular portion 11 a. In the present embodiment, the magnet 50 is disposed apart from both the 1 st axial wall portion 10a and the 2 nd axial wall portion 10b in the axial direction. The axial distance between magnet 50 and lid member 12 is substantially the same as the axial distance between magnet 50 and annular portion 11 a. The axial distance between the magnet 50 and the 1 st core portion 21 is smaller than the axial distance between the magnet 50 and the 2 nd core portion 22.

The magnet 50 is located radially inward of the bobbin 30 and the coil 40. In the present embodiment, the magnet 50 is located between the guide member 60 and the bobbin 30 in the radial direction. The outer peripheral surface of the magnet 50 is in contact with the inner peripheral surface of the bobbin 30. More specifically, the outer peripheral surface of the magnet 50 contacts the inner peripheral surface of the 1 st portion 31a of the bobbin trunk 31. The radially outer portion of the lower end surface of the magnet 50 is in contact with the stepped surface 34 a. Thereby, the lower end of the magnet 50 is supported from below by the stepped surface 34 a. The inner peripheral surface of the magnet 50 is located radially inward of the inner peripheral surface of the 2 nd portion 31b of the bobbin body 31. In the present embodiment, the magnet 50 is press-fitted to the inside in the radial direction of the bobbin 30. The magnet 50 is, for example, slightly pressed into the radial inside of the 1 st part 31 a.

The axial dimension of the magnet 50 is smaller than the axial dimension of the core body 72, the axial dimension of the bobbin 30, and the axial dimension of the coil 40. That is, in the present embodiment, the axial dimension of the core body 72 is larger than the axial dimension of the magnet 50. The upper end of the magnet 50 is located below the upper end of the coil 40. The lower end of magnet 50 is located above the lower end of coil 40. That is, the coil 40 protrudes to both axial sides from the magnet 50.

In the present embodiment, the axial position of the central portion in the axial direction of the magnet 50 is the same as the axial position of the central portion in the axial direction between the portion of the housing 10 located on the upper side of the core body 72 and the portion of the housing 10 located on the lower side of the core body 72. In the present embodiment, the portion of the case 10 located on the upper side of the core body 72 is the 1 st bottom wall portion 21 c. In the present embodiment, the portion of the case 10 located on the lower side of the core body 72 is the 2 nd bottom wall portion 22 c. The axial position of the central portion in the axial direction of magnet 50 is substantially the same as the axial position of the central portion in the axial direction of coil 40.

The guide member 60 is a cylindrical member that is open on both axial sides and extends in the axial direction. In the present embodiment, the guide member 60 is cylindrical with the center axis J as the center. The guide member 60 is made of a non-magnetic body. The guide member 60 is made of metal such as stainless steel. The guide member 60 is located radially outward of the core body 72. The guide member 60 is located radially inward of the bobbin 30 and the magnet 50. That is, in the present embodiment, the guide member 60 is positioned between the magnet 50 and the core body 72 in the radial direction. The guide member 60 is fitted with a gap radially inside the magnet 50.

The guide member 60 surrounds the core body 72. The guide member 60 supports the core body 72 to be movable in the axial direction. A core body 72 is fitted in a radially inner space of the guide member 60. The movable element 70 moves in the axial direction while a part of the outer peripheral surface of the core body 72 is in contact with the inner peripheral surface of the guide member 60, for example. In the present embodiment, for example, the movable element 70 is moved in the axial direction in a state where a part of the outer peripheral surface of the core center portion 72a of the core body 72 is in contact with the inner peripheral surface of the guide member 60.

The guide member 60 is located between the 1 st core portion 21 and the 2 nd core portion 22 in the axial direction. The upper end of the guide member 60 is fitted to the 1 st fitting portion 21 h. More specifically, the upper end of the guide member 60 is fitted radially inward of the 1 st fitting portion 21 h. The upper end of the guide member 60 is slightly pressed into the radial inner side of the 1 st fitting portion 21h, for example. The lower end of the guide member 60 is fitted to the 2 nd fitting portion 22 h. More specifically, the lower end of the guide member 60 is fitted into the 2 nd fitting portion 22h from the radially outer side. In other words, the 2 nd fitting portion 22h is fitted radially inward of the lower end of the guide member 60. The 2 nd fitting portion 22h is slightly press-fitted into the radial inner side of the lower end of the guide member 60, for example.

The upper end of the guide member 60 is disposed to face the lower side of the stepped surface 21 g. The lower end of the guide member 60 is disposed opposite the upper side of the stepped surface 22 f. Although not shown, a gap is provided between the upper end of the guide member 60 and the step surface 21g in the axial direction and between the lower end of the guide member 60 and the step surface 22f in the axial direction.

In the present embodiment, the spacer 61 is cylindrical surrounding the central axis J. More specifically, the spacer 61 is a cylindrical shape that is open on both sides in the axial direction with the center axis J as the center. The spacer 61 is made of a non-magnetic body. The spacer 61 is made of metal such as stainless steel. The spacer 61 is housed inside the case 10. Spacer 61 is located between 1 st axial wall 10a and magnet 50 in the axial direction. In the present embodiment, the spacer 61 is located between the radially outer peripheral edge of the 1 st cylindrical wall portion 21d of the 1 st core portion 21 and the radially outer peripheral edge of the magnet 50 in the axial direction.

The upper end of the spacer 61 contacts the step surface 21 f. The upper end of the spacer 61 is fitted to the 1 st fitting portion 21h from the radially outer side. In other words, the 1 st fitting portion 21h is fitted radially inward of the upper end of the spacer 61. As described above, in the present embodiment, the 1 st core portion 21 has the 1 st fitting portion 21h as a portion into which the upper end portion of the spacer 61 is fitted. The 1 st fitting portion 21h is slightly press-fitted into the radial inner side of the upper end of the spacer 61, for example. The lower end of the spacer 61 contacts the radially outer peripheral edge of the upper end surface of the magnet 50. Thereby, the upper end of the magnet 50 is supported from above by the spacer 61.

The axial dimension of the spacer 61 is smaller than the axial dimension of the guide member 60 and the axial dimension of the magnet 50. The axial dimension of the spacer 61 is larger than the axial dimension of the 1 st fitting portion 21 h. The radial thickness between the inner circumferential surface and the outer circumferential surface of the spacer 61 is larger than the radial thickness between the inner circumferential surface and the outer circumferential surface of the guide member 60. The spacer 61 is located radially outward of the guide member 60. The spacer 61 surrounds a portion of the guide member 60 that is fitted to the inside in the radial direction of the 1 st fitting portion 21 h. The spacer 61 is fitted with a clearance in the radial direction inside the bobbin 30. More specifically, the spacer 61 is fitted with a clearance in the radial direction inside the 1 st portion 31a of the bobbin trunk 31.

In the present embodiment, the elastic member 80 is a wave washer. The elastic member 80 is located between the bobbin 30 and the 2 nd axial wall portion 10b in the axial direction. In the present embodiment, the elastic member 80 is located between the recess 35 and the annular portion 11a in the axial direction. The elastic member 80 is annular surrounding the center axis J. In the present embodiment, the elastic member 80 is located radially outward of the 2 nd receiving portion 22b of the 2 nd core portion 22. The elastic member 80 surrounds the 2 nd accommodating portion 22 b. The elastic member 80 is in contact with the bobbin 30 and the 2 nd axial wall portion 10 b. More specifically, the elastic member 80 contacts a bottom surface facing downward of the inner surface of the recess 35 and an upper surface of the annular portion 11 a. The elastic member 80 is elastically deformed in a compressed state in the axial direction. Thereby, the elastic member 80 applies a force toward the upper side to the bobbin 30.

In the electric actuator 100 of the present embodiment, the movable element 70 can be moved to both sides in the axial direction by switching the direction of the current flowing through the coil 40. In fig. 1 and 3, the movable member 70 is shown in the uppermost state. Fig. 4 shows a state in which the movable element 70 is moved from the uppermost position to the halfway position of the lowermost position. In fig. 2 and 5, the movable member 70 is shown in a state of being located at the lowermost side. Fig. 6 shows a state in which the movable element 70 has moved from the lowermost position to the halfway position of the uppermost position. In the following description, the state in which the movable element 70 is positioned uppermost is referred to as "1 st state S1", and the state in which the movable element 70 is positioned lowermost is referred to as "2 nd state S2".

As shown in fig. 1 and 3, in the 1 st state S1, the core upper portion 72b of the core body 72 is housed inside the 1 st housing portion 21 b. In the present embodiment, in the 1 st state S1, the upper end surface of the core upper portion 72b contacts the 1 st bottom surface 21k, and the outer peripheral surface of the core upper portion 72b contacts the inner peripheral surface portion 21 j. In state 1S 1, the lower end of the core body 72 is positioned above the lower end of the magnet 50. In state 1S 1, the axial center portion of the core body 72 is located radially inward of the upper portion of the magnet 50. In the 1 st state S1, the center portion of the magnet 50 in the axial direction is located radially outward of the lower portion of the core center portion 72 a.

As shown in fig. 3, in the 1 st state S1, the magnetic flux from the magnet 50 flows through the core body 72 and the magnetic circuit Mm1 of the case 10. As shown by the arrows in fig. 3, in the magnetic circuit Mm1, the magnetic flux emitted radially inward from the magnetic pole portion 50N of the magnet 50 flows upward in the core body 72 and flows into the 1 st core portion 21. The magnetic flux flowing into the 1 st core portion 21 flows radially outward, passes through the lid member 12, and flows into the peripheral wall portion 11 b. The magnetic flux flowing into the peripheral wall portion 11b flows downward, and flows into the magnetic pole portion 50S of the magnet 50 from the radially outer side. A magnetic force of mutual attraction is generated between the core body 72 and the 1 st core portion 21 by the magnetic circuit Mm 1. Thus, even in a state where no current flows through the coil 40, the 1 st state S1 in which the movable element 70 is positioned uppermost is maintained.

Although not shown in fig. 3, in the 1 st state S1, the magnetic circuit Mm2 shown in fig. 4 is also generated. As shown by the arrows in fig. 4, in the magnetic circuit Mm2, the magnetic flux emitted from the magnetic pole portion 50N of the magnet 50 radially inward flows downward in the core body 72 and flows into the 2 nd core portion 22. The magnetic flux flowing into the 2 nd core portion 22 flows radially outward, passes through the annular portion 11a, and flows into the peripheral wall portion 11 b. The magnetic flux flowing into the peripheral wall portion 11b flows upward, and flows from the radial outside into the magnetic pole portion 50S of the magnet 50. A magnetic force attracting each other is generated between the core body 72 and the 2 nd core portion 22 by the magnetic circuit Mm 2. However, in the 1 st state S1, since the axial distance between the core body 72 and the 2 nd core portion 22 is larger than the axial distance between the core body 72 and the 1 st core portion 21, the magnetic flux flowing through the magnetic path Mm2 is smaller than the magnetic flux flowing through the magnetic path Mm 1. Thus, the magnetic force generated between the core body 72 and the 2 nd core portion 22 is smaller than the magnetic force generated between the core body 72 and the 1 st core portion 21. Therefore, even if the magnetic circuit Mm2 is generated in the 1 st state S1, the movement of the movable element 70 downward can be suppressed.

In the 1 st state S1, the mover 70 can be moved downward by passing a current through the coil 40 in a predetermined direction. Specifically, the movable element 70 in the 1 st state S1 can be moved downward by passing a current through the coil 40 in a direction in which the magnetic circuit Ms1 shown in fig. 4 is generated. In the example of fig. 4, the current flows through the coil 40 in a direction in which the current flows clockwise when viewed from the upper side. As shown by the arrows in fig. 4, in the magnetic circuit Ms1, the downward magnetic flux generated radially inward of the coil 40 flows from the core body 72 into the 2 nd core portion 22. The magnetic flux flowing into the 2 nd core portion 22 flows radially outward, passes through the annular portion 11a, and flows into the peripheral wall portion 11 b. The magnetic flux flowing into the peripheral wall portion 11b flows upward through the peripheral wall portion 11b and into the lid member 12. The magnetic flux flowing into the cover member 12 flows radially inward and flows into the 1 st core portion 21. The magnetic flux flowing into the 1 st core portion 21 flows downward and returns to the core body 72 from the upper side.

The direction in which the magnetic flux flows through the core 72 and the case 10 in the magnetic circuit Ms1 is opposite to the direction in which the magnetic flux flows through the core 72 and the case 10 in the magnetic circuit Mm1 shown in fig. 3. Thus, by generating magnetic circuit Ms1, at least a portion of magnetic circuit Mm1 is cancelled. Thereby, the magnetic force generated between the core body 72 and the 1 st core portion 21 is weakened. On the other hand, in the magnetic circuit Ms1, the direction in which the magnetic flux flows through the core 72 and the case 10 is the same as the direction in which the magnetic flux flows through the core 72 and the case 10 in the magnetic circuit Mm2 shown in fig. 4. Therefore, the magnetic force between the core body 72 and the 2 nd core part 22 generated by the magnetic circuit Mm2 can be enhanced by the magnetic circuit Ms 1. Accordingly, the magnetic force generated between the core body 72 and the 2 nd core portion 22 is larger than the magnetic force generated between the core body 72 and the 1 st core portion 21, and the thrust force PF1 directed downward is generated in the movable element 70. Therefore, the mover 70 moves downward by the propulsive force PF1, and the mover 70 is positioned at the lowermost position in the 2 nd state S2. In this way, by causing a current to flow through the coil 40 in a direction to generate the magnetic circuit Ms1 shown in fig. 4, the movable element 70 can be changed from the 1 st state S1 to the 2 nd state S2.

Further, the magnetic force between the core body 72 and the 2 nd core portion 22 generated by the magnetic circuit Mm2 increases as the movable element 70 moves downward. On the other hand, the magnetic force between the core body 72 and the 1 st core portion 21 generated by the magnetic circuit Mm1 becomes smaller as the movable element 70 moves downward.

As shown in fig. 5, in the 2 nd state S2, the core lower portion 72c of the core body 72 is housed inside the 2 nd housing portion 22 b. In the present embodiment, in the 2 nd state S2, the lower end surface of the core lower portion 72c contacts the 2 nd bottom surface 22k, and the outer peripheral surface of the core lower portion 72c contacts the inner peripheral surface 22 j. In state 2S 2, the upper end of the core body 72 is located above the upper end of the magnet 50. In state 2S 2, the axial center portion of the core body 72 is located radially inward of the lower portion of the magnet 50. In the 2 nd state S2, the center portion in the axial direction of the magnet 50 is located radially outward of the upper portion of the core center portion 72 a.

In the 2 nd state S2, the magnetic circuit Mm2 is constructed. As described above, the magnetic circuit Mm2 generates a magnetic force attracting each other between the core body 72 and the 2 nd core portion 22. Thus, even in a state where no current flows through the coil 40, the 2 nd state S2 where the mover 70 is positioned at the lowermost side is maintained. Although not shown in fig. 5, in the 2 nd state S2, the magnetic circuit Mm1 shown in fig. 3 is also generated. However, in the 2 nd state S2, since the axial distance between the core body 72 and the 1 st core portion 21 is larger than the axial distance between the core body 72 and the 2 nd core portion 22, the magnetic flux flowing through the magnetic path Mm1 is smaller than the magnetic flux flowing through the magnetic path Mm 2. Thus, the magnetic force generated between the core body 72 and the 1 st core portion 21 is smaller than the magnetic force generated between the core body 72 and the 2 nd core portion 22. Therefore, even if the magnetic circuit Mm1 is generated in the 2 nd state S2, the upward movement of the movable element 70 can be suppressed.

In the 2 nd state S2, the movable element 70 can be moved upward by passing a current through the coil 40 in a predetermined direction. Specifically, the movable element 70 in the 2 nd state S2 can be moved upward by passing a current through the coil 40 in a direction in which the magnetic circuit Ms2 shown in fig. 6 is generated. In the example of fig. 6, the current flows through the coil 40 in a direction of flowing counterclockwise when viewed from the upper side. That is, the direction of the current flowing through the coil 40 when the mover 70 in the 2 nd state S2 is moved upward is opposite to the direction of the current flowing through the coil 40 when the mover 70 in the 1 st state S1 is moved downward. As shown by the arrows in fig. 6, in the magnetic circuit Ms2, the magnetic flux that is generated radially inward of the coil 40 and that is directed upward flows from the core body 72 into the 1 st core portion 21. The magnetic flux flowing into the 1 st core portion 21 flows radially outward, passes through the lid member 12, and flows into the peripheral wall portion 11 b. The magnetic flux flowing into the peripheral wall portion 11b flows downward in the peripheral wall portion 11b and flows into the annular portion 11 a. The magnetic flux flowing into the annular portion 11a flows radially inward and flows into the 2 nd core portion 22. The magnetic flux flowing into the 2 nd core portion 22 flows to the upper side and returns to the core body 72 from the lower side.

The direction in which the magnetic flux flows through the core 72 and the case 10 in the magnetic circuit Ms2 is opposite to the direction in which the magnetic flux flows through the core 72 and the case 10 in the magnetic circuit Mm2 shown in fig. 5. Thus, by generating magnetic circuit Ms2, at least a portion of magnetic circuit Mm2 is cancelled. This weakens the magnetic force generated between the core body 72 and the 2 nd core portion 22. On the other hand, in the magnetic circuit Ms2, the direction in which the magnetic flux flows through the core 72 and the case 10 is the same as the direction in which the magnetic flux flows through the core 72 and the case 10 in the magnetic circuit Mm1 shown in fig. 6. Therefore, the magnetic force between the core body 72 and the 1 st core portion 21 generated by the magnetic circuit Mm1 can be enhanced by the magnetic circuit Ms 2. Accordingly, the magnetic force generated between the core body 72 and the 1 st core portion 21 is larger than the magnetic force generated between the core body 72 and the 2 nd core portion 22, and the thrust force PF2 toward the upper side is generated in the mover 70. Therefore, the mover 70 is moved upward by the propulsive force PF2, and the mover 70 is positioned at the uppermost 1 st position S1. In this way, by causing a current to flow through the coil 40 in a direction to generate the magnetic circuit Ms2 shown in fig. 6, the movable element 70 can be changed from the 2 nd state S2 to the 1 st state S1.

Further, the magnetic force between the core body 72 and the 1 st core portion 21 generated by the magnetic circuit Mm1 becomes larger as the movable element 70 moves upward. On the other hand, the magnetic force between the core body 72 and the 2 nd core portion 22 generated by the magnetic circuit Mm2 becomes smaller as the movable element 70 moves upward.

As described above, the electric actuator 100 of the present embodiment is a self-holding type solenoid actuator capable of holding the 1 st state S1 in which the movable element 70 is positioned at the uppermost side and the 2 nd state S2 in which the movable element 70 is positioned at the lowermost side without causing a current to flow through the coil 40. In the electric actuator 100, the direction of the current flowing through the coil 40 is changed, whereby the movable element 70 can be moved to either one of the two sides in the axial direction.

According to the present embodiment, the magnet 50 is located radially inward of the coil 40. Therefore, as described above, by passing a current through the magnetic circuits Ms1 and Ms2 generated by one coil 40, one of the magnetic circuit Mm1 and the magnetic circuit Mm2 generated by the magnet 50 can be weakened and the other can be strengthened. Thereby, the balance between the magnetic force generated between the core body 72 and the upper portion of the case 10 and the magnetic force generated between the core body 72 and the lower portion of the case 10 can be changed according to the direction of the current flowing through the coil 40. Therefore, as described above, by switching the direction of the current flowing through one coil 40, the movable element 70 can be moved to both sides in the axial direction. Therefore, it is not necessary to provide two or more coils 40, and the electric actuator 100 can be downsized in the axial direction. Further, since the movable element 70 can be moved to both axial sides only by changing the direction of the current flowing through one coil 40, the current supplied to the coil 40 can be easily controlled as compared with the case where a plurality of coils 40 are provided.

In addition, by moving the movable element 70 in the axial direction, the magnetic path of the magnetic flux flowing through the portion of the case 10 on the side where the movable element 70 moves and the core body 72 can be strengthened, and the magnetic path of the magnetic flux flowing through the portion of the case 10 on the opposite side to the side where the movable element 70 moves and the core body 72 can be weakened. Therefore, in a state where the core body 72 is sufficiently close to one of the upper portion of the case 10 and the lower portion of the case 10, the magnetic flux flowing in the magnetic path of the magnet 50 generated in the core body 72 and the other of the upper portion of the case 10 and the lower portion of the case 10 can be made sufficiently small with respect to the magnetic flux flowing in the magnetic path of the magnet 50 generated in the core body 72 and one of the upper portion of the case 10 and the lower portion of the case 10. Accordingly, in the 1 st state S1 in which the mover 70 is positioned uppermost and the 2 nd state S2 in which the mover 70 is positioned lowermost, the axial position of the mover 70 can be held only by the magnetic force generated by the magnet 50 without causing a current to flow through the coil 40. Thus, the self-holding type electric actuator 100 having one coil 40 is obtained.

In addition, according to the present embodiment, the magnet 50 is located radially inward of the coil 40. Therefore, for example, the magnet 50 can be disposed closer to the iron core body 72 than in the case where the magnet 50 is located radially outward of the coil 40. This facilitates the magnetic flux of the magnet 50 to flow through the core body 72. Therefore, magnetic paths Mm1 and Mm2 passing through iron core 72 are easily generated by magnet 50. Therefore, the movable member 70 can be better moved in the axial direction, and the movable member 70 can be better held in the 1 st state S1 and the 2 nd state S2.

Further, according to the present embodiment, the magnet 50 is located between the 1 st axial wall portion 10a and the 2 nd axial wall portion 10b in the axial direction, and is disposed so as to be separated from both the 1 st axial wall portion 10a and the 2 nd axial wall portion 10b in the axial direction. Therefore, the magnetic flux of magnet 50 can be suppressed from flowing directly from magnet 50 to first axial wall 10a and second axial wall 10 b. This allows the magnetic flux of magnet 50 to flow through core body 72 more favorably. Therefore, the magnetic paths Mm1 and Mm2 passing through the iron core 72 are more easily and appropriately generated by the magnet 50. Therefore, the movable member 70 can be better moved in the axial direction, and the movable member 70 can be better held in the 1 st state S1 and the 2 nd state S2.

Further, according to the present embodiment, the 1 st axial wall portion 10a has the 1 st core portion 21 located above the core body 72, and the 2 nd axial wall portion 10b has the 2 nd core portion 22 located below the core body 72. Therefore, the magnetic flux easily flows between the core body 72 and the housing 10 via the 1 st core portion 21 and the 2 nd core portion 22. This makes it possible to easily generate the magnetic circuits Mm1, Mm2, Ms1, and Ms 2.

In addition, according to the present embodiment, the axial position of the center portion in the axial direction of the magnet 50 is the same as the axial position of the center portion in the axial direction between the portion of the housing 10 located above the core body 72, that is, the 1 st bottom wall portion 21c, and the portion of the housing 10 located below the core body 72, that is, the 2 nd bottom wall portion 22 c. Therefore, for example, when the core body 72 is positioned at the axial center of the 1 st bottom wall portion 21c and the 2 nd bottom wall portion 22c, the magnetic paths Mm1 and Mm2 generated by the magnet 50 are easily generated to a relatively equal degree. Accordingly, the movable element 70 can be easily moved to both sides in the axial direction, and the movable element 70 can be easily and appropriately held in both the 1 st state S1 and the 2 nd state S2.

In addition, according to the present embodiment, the coil 40 protrudes to both axial sides from the magnet 50. Therefore, the coil 40 can be made relatively large in the axial direction, and the magnetic flux flowing through the magnetic circuits Ms1 and Ms2 generated by the current flowing through the coil 40 can be made relatively large. Thus, the magnetic circuits Ms1 and Ms2 can easily weaken one of the magnetic circuit Mm1 and the magnetic circuit Mm2 generated by the magnet 50, and can easily strengthen the other of the magnetic circuit Mm1 and the magnetic circuit Mm 2.

In addition, according to the present embodiment, the axial dimension of the core body 72 is larger than the axial dimension of the magnet 50. Therefore, in each of the 1 st state S1 and the 2 nd state S2, the axial dimension of the portion of the core body 72 located radially inward of the magnet 50 can be increased. Accordingly, in each of the 1 st state S1 and the 2 nd state S2, the amount of magnetic flux flowing from the magnet 50 to the core body 72 can be increased as appropriate. Therefore, in the 1 st state S1, the amount of magnetic flux generated by the magnet 50 and flowing through the magnetic circuit Mm1 can be increased as appropriate, and in the 2 nd state S2, the amount of magnetic flux generated by the magnet 50 and flowing through the magnetic circuit Mm2 can be increased as appropriate. Therefore, in each of the 1 st state S1 and the 2 nd state S2, the axial position of the movable element 70 can be maintained more favorably.

In addition, according to the present embodiment, the spacer 61 is positioned between the 1 st axial wall portion 10a and the magnet 50 in the axial direction. A step portion 34 having a step surface 34a facing upward is provided on the inner peripheral surface of the bobbin 30. The upper end of magnet 50 is supported from above by spacer 61, and the lower end of magnet 50 is supported from below by step surface 34 a. Therefore, the magnet 50 can be positioned in the axial direction by the spacer 61 and the step surface 34a of the bobbin 30. This enables the magnet 50 to be appropriately positioned in the axial direction with respect to the coil 40 wound around the bobbin 30. Therefore, it is possible to suppress the balance between the magnetic circuits Mm1, Mm2 generated by the magnet 50 and the magnetic circuits Ms1, Ms2 generated by the coil 40 from being broken. Therefore, the occurrence of a failure in the axial movement of the movable element 70 can be suppressed. Further, an assembly method may be adopted in which the spacer 61 is disposed above the magnet 50 after the lower end of the magnet 50 is brought into contact with the stepped surface 34 a. Therefore, the magnet 50 can be positioned in the axial direction with respect to the coil 40, and the reduction in the assembling property of the electric actuator 100 can be suppressed.

In addition, according to the present embodiment, the spacer 61 is cylindrical surrounding the central axis J. Therefore, the magnet 50 can be supported more stably by the spacer 61.

In addition, according to the present embodiment, the 1 st core portion 21 has the 1 st fitting portion 21h, and the 1 st fitting portion 21h is a portion into which the upper end portion of the spacer 61 is fitted. Therefore, the upper end portion of the spacer 61 can be stably held by the 1 st core portion 21. This can suppress the radial position displacement of the spacer 61. Therefore, the spacer 61 can support the magnet 50 more stably.

In addition, according to the present embodiment, the magnet 50 is press-fitted to the inner side in the radial direction of the bobbin 30. Therefore, the magnet 50 can be appropriately held by the bobbin 30. This can suppress the radial position of the magnet 50 from being displaced with respect to the coil 40. Therefore, it is possible to further suppress the balance breakdown of the magnetic circuits Mm1, Mm2 by the magnet 50 and the magnetic circuits Ms1, Ms2 by the coil 40. Therefore, the occurrence of the failure in the axial movement of the movable element 70 can be further suppressed.

In addition, according to the present embodiment, the electric actuator 100 includes the elastic member 80 that is positioned between the bobbin 30 and the 2 nd axial wall portion 10b in the axial direction and applies a force toward the upper side to the bobbin 30. Therefore, the stepped surface 34a can be pressed against the lower end of the magnet 50 by the upward force applied to the bobbin 30 by the elastic member 80. This allows the magnet 50 to be pressed against the spacer 61, and the magnet 50 can be held between the step surface 34a and the spacer 61 in the axial direction. Even if a variation such as a dimensional tolerance occurs in the axial distance between the 1 st axial wall portion 10a and the 2 nd axial wall portion 10b, the variation can be absorbed by the elastic deformation of the elastic member 80. Therefore, the magnet 50 can be brought into contact with both the stepped surface 34a and the spacer 61 appropriately regardless of dimensional variations of the case 10. This enables the magnet 50 to be positioned more favorably with respect to the coil 40.

Further, according to the present embodiment, the electric actuator 100 includes the guide member 60 that supports the core body 72 so as to be movable in the axial direction. Therefore, the core body 72 can be prevented from being inclined in the radial direction by the guide member 60. This enables the core body 72 to be appropriately moved in the axial direction.

In addition, according to the present embodiment, the magnet 50 is located between the guide member 60 and the bobbin 30 in the radial direction. Therefore, the position of the magnet 50 can be further suppressed from being displaced in the radial direction by the guide member 60 and the bobbin 30. This can further suppress the balance between the magnetic circuits Mm1, Mm2 by the magnet 50 and the magnetic circuits Ms1, Ms2 by the coil 40 from being lost. Therefore, the occurrence of a failure in the axial movement of the movable element 70 can be further suppressed.

In addition, according to the present embodiment, the area of the portion overlapping with the core body 72 when viewed in the axial direction in the lower surface of the 1 st core portion 21 is larger than the area of the portion overlapping with the core body 72 when viewed in the axial direction in the upper surface of the 2 nd core portion 22. Therefore, the amount of magnetic flux flowing between the core body 72 and the 1 st core portion 21 can be made larger than the amount of magnetic flux flowing between the core body 72 and the 2 nd core portion 22. Accordingly, the amount of magnetic flux generated by magnet 50 and flowing through magnetic circuit Mm1 can be made larger than the amount of magnetic flux generated by magnet 50 and flowing through magnetic circuit Mm 2. Therefore, the magnitude of the thrust PF2 toward the upper side generated by the movable element 70 when the state changes from the 2 nd state S2 to the 1 st state S1 can be made larger than the magnitude of the thrust PF1 toward the lower side generated by the movable element 70 when the state changes from the 1 st state S1 to the 2 nd state S2. Therefore, the output of the electric actuator 100 transmitted to another device via the shaft 71 can be made different depending on the direction in which the movable element 70 moves. Thus, for example, when two drives different in required driving force are performed by the electric actuator 100, the output of the electric actuator 100 from the shaft 71 can be changed in accordance with the driving force required for each drive. Therefore, for example, two kinds of driving requiring different driving forces can be performed by the electric actuator 100 without increasing the output of the entire electric actuator 100 according to the larger driving force among the required driving forces. Therefore, the electric actuator 100 can be easily miniaturized.

Further, since the amount of magnetic flux generated by the magnet 50 and flowing through the magnetic circuit Mm1 can be made larger than the amount of magnetic flux generated by the magnet 50 and flowing through the magnetic circuit Mm2, the holding force for holding the movable element 70 in the 1 st state S1 can be made larger than the holding force for holding the movable element 70 in the 2 nd state S2. Thus, when one of the holding states of the mover 70 requires a larger holding force than the other, the state of the mover 70 can be appropriately held by setting the one holding state to the 1 st state S1.

In the present embodiment, the electric actuator 100 is in the locked state in which the gear of the vehicle is in the parked state in the 1 st state S1, and the electric actuator 100 is in the unlocked state in which the gear of the vehicle is not in the parked state in the 2 nd state S2. Therefore, since the holding force for holding the mover 70 in the 1 st state S1 can be increased, the locked state in which the gear of the vehicle is in the parked state can be appropriately maintained.

As shown in fig. 2, in the present embodiment, a force directed upward is applied to a portion of the arm a located on the opposite side of the end portion coupled to the shaft 71 with respect to the rotation axis R, so that a force directed downward can be applied to the shaft 71 via the arm a. Therefore, even when a current flows through the coil 40, the mover 70 in the 1 st state S1 does not move downward, and a downward force is applied to the shaft 71 via the arm a to move the mover 70 downward, so that the mover 70 can be brought into the 2 nd state S2. Therefore, even when the downward thrust force PF1 generated in the movable element 70 is insufficient, the movable element 70 can be switched from the 1 st state S1 to the 2 nd state S2. That is, even if the propulsive force PF1 is relatively small, the state can be switched from the 1 st state S1 to the 2 nd state S2. On the other hand, in the present embodiment, the movable element 70 is not urged upward via the arm a. Therefore, the thrust force PF2 generated in the movable element 70 toward the upper side is preferably sufficiently large. In contrast, in the present embodiment, as described above, the magnitude of the propulsive force PF2 can be made larger than the magnitude of the propulsive force PF 1. Therefore, it is possible to suppress the shortage of the propulsive force PF2 for switching the movable element 70 from the 2 nd state S2 to the 1 st state S1. As described above, according to the present embodiment, in the electric actuator 100 mounted on the parking-by-wire actuator device, the state of the mover 70 can be appropriately switched.

Further, according to the present embodiment, the 1 st core portion 21 includes the 1 st receiving portion 21b capable of receiving the upper end portion of the core body 72 therein. Therefore, the area of the 1 st core portion 21 facing the core body 72 in the 1 st state S1 can be increased. This can appropriately increase the amount of magnetic flux generated by magnet 50 in state 1S 1 and flowing through magnetic circuit Mm 1. Therefore, the movable element 70 can be better maintained in the 1 st state S1.

Further, according to the present embodiment, the 2 nd core portion 22 includes the 2 nd receiving portion 22b capable of receiving the lower end portion of the core body 72 therein. Therefore, the area of the 2 nd core portion 22 facing the core body 72 in the 2 nd state S2 can be increased. This can appropriately increase the amount of magnetic flux generated by magnet 50 in state 2S 2 and flowing through magnetic circuit Mm 2. Therefore, the movable element 70 can be better maintained in the 2 nd state S2.

In addition, according to the present embodiment, the area of the inner surface 21p of the 1 st housing part 21b is larger than the area of the inner surface 22p of the 2 nd housing part 22 b. Therefore, the holding force of the movable element 70 in the 1 st state S1 can be made appropriately larger than the holding force of the movable element 70 in the 2 nd state S2. Further, the magnitude of the propulsive force PF2 can be made appropriately larger than the magnitude of the propulsive force PF 1.

Further, according to the present embodiment, the 1 st housing portion 21b includes the 1 st bottom wall portion 21c located above the core body 72 and the 1 st cylindrical wall portion 21d protruding downward from the radially outer peripheral edge portion of the 1 st bottom wall portion 21 c. Therefore, the upper end portion of the core body 72 that has moved upward from the 2 nd state S2 can be easily housed in the 1 st cylindrical wall portion 21d, and the axial position of the core body 72 can be easily positioned at the position of the 1 st state S1 by the 1 st bottom wall portion 21 c.

In addition, according to the present embodiment, the 2 nd housing portion 22b includes the 2 nd bottom wall portion 22c located below the core body 72 and the 2 nd cylindrical wall portion 22d protruding upward from the radially outer peripheral edge portion of the 2 nd bottom wall portion 22 c. Therefore, the lower end portion of the core body 72 that has moved downward from the 1 st state S1 can be easily housed in the 2 nd cylindrical wall portion 22d, and the axial position of the core body 72 can be easily positioned at the position of the 2 nd state S2 by the 2 nd bottom wall portion 22 c.

In addition, according to the present embodiment, at least a part of the 1 st cylindrical wall portion 21d and at least a part of the 2 nd cylindrical wall portion 22d are located radially inward of the coil 40. Therefore, the area of the inner surfaces 21p, 22p of the respective housing portions can be increased by increasing the axial size of the 1 st cylindrical wall portion 21d and the 2 nd cylindrical wall portion 22d, and the entire electric actuator 100 can be prevented from being increased in the axial size.

In addition, according to the present embodiment, the volume of the 1 st iron core portion 21 is larger than the volume of the 2 nd iron core portion 22. Therefore, the amount of magnetic flux flowing between the core body 72 and the 1 st core portion 21 is likely to be larger than the amount of magnetic flux flowing between the core body 72 and the 2 nd core portion 22. Therefore, the magnitude of the thrust PF2 toward the upper side generated in the movable element 70 when the state is changed from the 2 nd state S2 to the 1 st state S1 is easily made larger than the magnitude of the thrust PF1 toward the lower side generated in the movable element 70 when the state is changed from the 1 st state S1 to the 2 nd state S2.

In addition, according to the present embodiment, the radial dimension of the 1 st iron core portion 21 is larger than the radial dimension of the 2 nd iron core portion 22. Therefore, the area of the portion overlapping with the core body 72 when viewed in the axial direction in the lower surface of the 1 st core portion 21 can be easily made larger than the area of the portion overlapping with the core body 72 when viewed in the axial direction in the upper surface of the 2 nd core portion 22.

For example, even when the area of the portion overlapping with the core body 72 in the axial view on the surface facing the lower side of the 1 st core portion 21 is the same as the area of the portion overlapping with the core body 72 in the axial view on the surface facing the upper side of the 2 nd core portion 22, the amount of magnetic flux generated by the magnet 50 and flowing through the magnetic path Mm1 can be made larger than the amount of magnetic flux generated by the magnet 50 and flowing through the magnetic path Mm2 by disposing the magnet 50 closer to the 1 st axial wall portion 10 a. However, in this case, the magnetic flux of the magnet 50 is less likely to flow to the 2 nd axial wall portion 10b, and even if the axial position of the magnet 50 is slightly shifted, the balance between the magnetic path Mm1 and the magnetic path Mm2 is likely to be lost. Therefore, a failure is likely to occur in the axial movement of the movable element 70.

In contrast, according to the present embodiment, as described above, the area of the portion of the 1 st core portion 21 facing downward that overlaps with the core body 72 as viewed in the axial direction is larger than the area of the portion of the 2 nd core portion 22 facing upward that overlaps with the core body 72 as viewed in the axial direction. Further, magnet 50 is positioned between 1 st axial wall portion 10a and 2 nd axial wall portion 10b in the axial direction, and is disposed so as to be axially separated from both of 1 st axial wall portion 10a and 2 nd axial wall portion 10 b. Therefore, the magnet 50 can be disposed at a certain distance from both the 1 st axial wall 10a and the 2 nd axial wall 10b in the axial direction. Accordingly, even if magnet 50 is slightly displaced in the axial direction, the balance between magnetic circuit Mm1 and magnetic circuit Mm2 is not easily broken, and the amount of magnetic flux generated by magnet 50 and flowing through magnetic circuit Mm1 can be made larger than the amount of magnetic flux generated by magnet 50 and flowing through magnetic circuit Mm 2.

In addition, in the present embodiment, as described above, the axial position of the central portion in the axial direction of the magnet 50 is the same as the axial position of the central portion in the axial direction between the portion of the housing 10 located on the upper side of the core body 72 and the portion of the housing 10 located on the lower side of the core body 72. Therefore, the magnet 50 can be disposed to be more separated from both the 1 st axial wall portion 10a and the 2 nd axial wall portion 10b in the axial direction. Accordingly, even when magnet 50 is slightly displaced in the axial direction, the balance between magnetic circuit Mm1 and magnetic circuit Mm2 can be further suppressed from being lost.

Further, according to the present embodiment, the guide member 60 supports the core body 72 so as to be movable in the axial direction. The 1 st through hole 21e supports the shaft 71 to be movable in the axial direction. Therefore, the movable element 70 can be supported by the guide member 60 and the 1 st through hole 21e so as to be movable in the axial direction. This can increase the area of the portion that supports the movable element 70 so as to be movable in the axial direction. Therefore, the movable element 70 can be stably supported. Further, by supporting the movable element 70 by two portions having different axial positions, the inclination of the movable element 70 in the radial direction can be appropriately suppressed.

In addition, according to the present embodiment, the difference between the inner diameter of the 2 nd through hole 22e and the outer diameter of the portion of the shaft 71 passing through the 2 nd through hole 22e is larger than the difference between the inner diameter of the 1 st through hole 21e and the outer diameter of the portion of the shaft 71 passing through the 1 st through hole 21 e. Therefore, the inner peripheral surface of the 2 nd through hole 22e can be spaced apart from the outer peripheral surface of the shaft 71, and the outer peripheral surface of the shaft 71 can be prevented from coming into contact with the inner peripheral surface of the 2 nd through hole 22 e. This allows only the 1 st through hole 21e to support the shaft 71, and reduces the frictional force generated between the shaft 71 and the housing 10. Therefore, even when a relatively large radial force is applied to the shaft 71, the shaft 71 can be prevented from being worn due to friction.

In addition, according to the present embodiment, the inner diameter of the 2 nd through hole 22e is larger than the inner diameter of the 1 st through hole 21 e. Therefore, even if the outer diameter of the portion of the shaft 71 that passes through the 1 st through hole 21e is the same as the outer diameter of the portion of the shaft 71 that passes through the 2 nd through hole 22e, the difference between the inner diameter of the 2 nd through hole 22e and the outer diameter of the portion of the shaft 71 that passes through the 2 nd through hole 22e can be made larger than the difference between the inner diameter of the 1 st through hole 21e and the outer diameter of the portion of the shaft 71 that passes through the 1 st through hole 21 e. This makes it easy to form the shaft 71 into a simple shape.

In addition, according to the present embodiment, the 1 st through hole 21e is provided in the 1 st core portion 21, and the 2 nd through hole 22e is provided in the 2 nd core portion 22. Therefore, when the core body 72 is moved to the 1 st core portion 21 by the relatively large thrust force PF2, the shaft 71 can be supported by the 1 st through hole 21e provided in the 1 st core portion 21. Accordingly, when the amount of movement of the core body 72 becomes relatively large due to the propulsive force PF2, the movable element 70 can be supported at a position relatively close to the core body 72. Therefore, even when the amount of movement of the core body 72 is relatively large, the core body 72 can be more favorably suppressed from being inclined in the radial direction.

In addition, according to the present embodiment, the guide member 60 is located between the 1 st core portion 21 and the 2 nd core portion 22 in the axial direction. Therefore, the guide member 60 can be sandwiched and supported in the axial direction by the 1 st core portion 21 and the 2 nd core portion 22. This can suppress the axial displacement of the guide member 60. Therefore, the core body 72 can be further suppressed from being inclined in the radial direction by the guide member 60. Therefore, the core body 72 can be moved more appropriately in the axial direction.

In addition, according to the present embodiment, the 1 st core portion 21 has the 1 st fitting portion 21h that fits to the upper end portion of the guide member 60. The 2 nd core part 22 has a 2 nd fitting part 22h fitted to the lower end of the guide member 60. Therefore, the radial position shift of the guide member 60 can be suppressed by the 1 st core portion 21 and the 2 nd core portion 22. This can further suppress the inclination of the core body 72 in the radial direction by the guide member 60. Therefore, the core body 72 can be moved in the axial direction better.

In addition, according to the present embodiment, the guide member 60 is located between the magnet 50 and the core body 72 in the radial direction. Therefore, the core body 72 can be supported by the guide member 60 so as to be movable in the axial direction, and the magnet 50 can be positioned in the radial direction by the guide member 60.

The present invention is not limited to the above embodiment, and other structures and other methods can be adopted within the scope of the technical idea of the present invention. The magnets may also be located radially outward of the coils. In this case as well, the movable element can be moved to both sides in the axial direction by one coil, and the movable element can be held at both positions in the axial direction without passing a current through the coil, as in the above-described embodiment.

The magnet may be disposed at any position as long as it is located radially inside or radially outside the coil. The magnet may be disposed in contact with either the 1 st axial wall portion or the 2 nd axial wall portion. The magnet may be fitted with a gap radially inside the bobbin. The magnet may be fixed to the bobbin by an adhesive. The relative size relationship between the magnet and the coil in the axial direction is not particularly limited. The axial dimension of the magnet may be greater than the axial dimension of the coil. The magnets may be formed of three or more individual magnets. The magnet may be a single component. The relative dimensional relationship between the magnet and the core body in the axial direction is not particularly limited. The axial dimension of the magnet may be greater than the axial dimension of the core body.

The shape of the 1 st iron core portion and the shape of the 2 nd iron core portion are not particularly limited. The shape of the 1 st iron core portion and the shape of the 2 nd iron core portion may also be identical to each other. The volume of the 1 st iron core portion may be the same as or smaller than that of the 2 nd iron core portion. The radial dimension of the 1 st iron core portion may be the same as or smaller than the radial dimension of the 2 nd iron core portion.

The 1 st core part may not have the 1 st housing part. The 2 nd core part may not have the 2 nd housing part. The 1 st core part may not have a portion fitted to the end portion on one axial side of the spacer. The 1 st core part may not have the 1 st fitting part. The 2 nd core part may not have the 2 nd fitting part.

The difference between the inner diameter of the 2 nd through hole and the outer diameter of the portion of the shaft passing through the 2 nd through hole may be the same as the difference between the inner diameter of the 1 st through hole and the outer diameter of the portion of the shaft passing through the 1 st through hole, or may be smaller than the difference between the inner diameter of the 1 st through hole and the outer diameter of the portion of the shaft passing through the 1 st through hole. The inner diameter of the 1 st through hole and the inner diameter of the 2 nd through hole may be the same as each other. The shaft may be supported so as to be movable in the axial direction by both the 1 st through hole and the 2 nd through hole. Both the 1 st through hole and the 2 nd through hole may not support the shaft. The 1 st through hole may be provided in the 2 nd core part, and the 2 nd through hole may be provided in the 1 st core part.

The spacer may be of any shape. The spacer may be provided in plurality in the circumferential direction. The spacer may be retained in any manner. The end of the spacer on one side in the axial direction may not be fitted to the 1 st core. The spacer may not be provided. The elastic member is located between the bobbin and the 2 nd axial wall portion in the axial direction, and any type of elastic member may be used as long as a force toward one axial side is applied to the bobbin. The elastic member may be a coil spring. The elastic member may not be provided. The guide member may be retained in any manner. The guide member may not be provided.

The use of the electric actuator to which the present invention is applied is not particularly limited. The electric actuator may be mounted on an actuator device of a shift-by-wire system that is driven based on a shift operation by a driver of the vehicle. The electric actuator may be mounted on a device other than the vehicle. In addition, the respective structures and the respective methods described in the present specification can be appropriately combined within a range not inconsistent with each other.

Claims (9)

1. An electric actuator, characterized in that,

the electric actuator includes:

a movable piece having an iron core body made of a magnetic body, the movable piece being movable in an axial direction along a center axis;

a coil located radially outside the core body, surrounding the core body;

a magnetic body case that houses the core body and the coil therein; and

a magnet housed inside the case, the magnet being positioned radially inside the coil or radially outside the coil,

the housing has:

a peripheral wall portion located radially outward of the coil and surrounding the coil;

a 1 st axial wall portion located on one axial side of the coil; and

a 2 nd axial wall portion located on the other axial side of the coil,

the 1 st axial wall portion has a 1 st core portion located on one axial side of the core body,

the 2 nd axial wall portion has a 2 nd core portion located on the other axial side of the core body,

an area of a portion of the 1 st core portion facing the other axial side that overlaps with the core body as viewed in the axial direction is larger than an area of a portion of the 2 nd core portion facing the one axial side that overlaps with the core body as viewed in the axial direction.

2. Electric actuator according to claim 1,

the 1 st core part has a 1 st receiving part capable of receiving an end part of the core body at one axial side therein,

the 2 nd core portion has a 2 nd receiving portion capable of receiving an end portion of the core body on the other side in the axial direction therein,

the area of the inner surface of the 1 st receiving part is larger than that of the inner surface of the 2 nd receiving part.

3. The electric actuator of claim 2,

the 1 st housing part includes:

a 1 st bottom wall portion located on one axial side of the core body; and

a 1 st cylindrical wall portion protruding from a radial outer peripheral edge portion of the 1 st bottom wall portion toward the other axial side,

the 2 nd housing part includes:

a 2 nd bottom wall portion located on the other axial side of the core body; and

and a 2 nd cylindrical wall portion protruding from a radially outer peripheral edge portion of the 2 nd bottom wall portion toward one axial side.

4. The electric actuator according to claim 3,

at least a portion of the 1 st cylindrical wall portion and at least a portion of the 2 nd cylindrical wall portion are located radially inward of the coil.

5. The electric actuator according to any one of claims 1 to 4,

the 1 st iron core has a volume larger than that of the 2 nd iron core.

6. The electric actuator according to any one of claims 1 to 4,

the 1 st core portion has a radial dimension larger than that of the 2 nd core portion.

7. The electric actuator according to any one of claims 1 to 4,

the magnet is located between the 1 st axial wall portion and the 2 nd axial wall portion in the axial direction and is disposed so as to be axially separated from both the 1 st axial wall portion and the 2 nd axial wall portion.

8. The electric actuator according to any one of claims 1 to 4,

an axial position of the central portion in the axial direction of the magnet is the same as an axial position of the central portion in the axial direction between a portion of the housing located on one side in the axial direction of the core body and a portion of the housing located on the other side in the axial direction of the core body.

9. The electric actuator according to any one of claims 1 to 4,

the magnet is located radially inward of the coil.

Images