JP2012210030A - Linear actuator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a linear actuator which can avoid increase in a radial dimension.SOLUTION: A linear actuator 1 includes: an annular stator 20 including a coil 21 and fixed to an inner peripheral face of a housing 10 which has a cylindrical space 11 inside; a needle 30 which has a permanent magnet 31 mounted to a shaft member 33 arranged coaxially with an axial center O of the stator 20 and is movable in the axial center direction with respect to the stator 20; a terminal part 24 extending from part of an end part in the axial center direction of the stator 20 to the axial center direction and connecting the coil 21 to an external electric power supply source; and leaf spring members 40 which are disposed at both ends in the axial center direction of the needle 30 and in which at least portions of peripheral edge parts are fixed to the side of the stator 20 and central parts are fixed to the side of the needle 30. A notch part 40b preventing interference with the terminal part 24 is formed at the peripheral edge part of each of the leaf spring members 40.

Description

  An annular stator that is fixed with a coil, a mover that is arranged on the same axis as the axis of the stator with a permanent magnet, and that can move in the axial direction with respect to the stator; The present invention relates to a linear actuator provided with a leaf spring member disposed between and a child.

  For example, in Patent Document 1, a stator having a coil is disposed inside a cylindrical mover having a permanent magnet on the inner peripheral side, and one end of a leaf spring provided therebetween is the mover. A linear actuator is disclosed in which the other end is fixed to the stator. Such a leaf spring is deformed with the vibration of the mover, and depending on the shape of the leaf spring, there is a problem that the stress is locally concentrated and the spring characteristics are deteriorated or the spring breaks. In order to solve such a problem, the linear actuator described in Patent Document 1 is obtained by improving the shape of a leaf spring so that stress concentration generated in the leaf spring can be reduced.

  Further, in Patent Document 2, a stator having a coil is disposed outside a mover having a permanent magnet, and a central portion of a leaf spring provided therebetween is fixed to the mover side. A linear actuator having a peripheral edge fixed to the stator side is disclosed. In this linear actuator, the length of the permanent magnet in the axial direction is equal to or less than the length of the teeth that form the central magnetic pole of the stator, so that vibration with high efficiency and excellent response to high frequencies can be achieved. It is supposed to be possible.

JP 2004-328805 A JP 2009-240138 A

  Patent Documents 1 and 2 do not describe how to take out a coil winding and connect it to an external power supply source. However, considering that leaf springs are disposed at both ends in the axial direction, it is considered that the coil winding is taken out radially and connected to the power supply source. Therefore, in the linear actuators described in Patent Documents 1 and 2, the radial dimension becomes large, and it is impossible to cope with the case where the radial dimension has to be reduced due to the location of the linear actuator. was there.

  In view of the above problems, an object of the present invention is to provide a linear actuator that can avoid an increase in radial dimension.

  The characteristic configuration of the linear actuator according to the present invention includes an annular stator fixed with a coil on an inner peripheral surface of a housing having a cylindrical space inside, and a coaxial axis with the axis of the stator. A permanent magnet attached to the shaft member, movable relative to the stator in the axial direction, and extending from the end of the stator in the axial direction in the axial direction. A terminal portion that connects the coil to an external power supply source, and is disposed at both ends in the axial direction of the mover, and at least a part of a peripheral edge portion is fixed to the stator side; A leaf spring member that is fixed to the movable element side, and a notch portion that prevents interference with the terminal portion is formed at the peripheral edge portion of the leaf spring member.

  According to this characteristic configuration, the terminal portion is formed in the axial direction from the end portion in the axial direction of the stator, and the leaf spring members provided at both ends in the axial direction of the mover interfere with the terminal portion. In order to prevent this, since the notch portion is formed in the peripheral edge portion of the leaf spring member, the leaf spring member can be disposed so as not to interfere with the terminal portion. Therefore, in the linear actuator having this characteristic configuration, the coil winding can be taken out in the axial direction, and the increase in the radial dimension can be avoided.

  Here, an engaging portion is formed in the cutout portion, and an engaged portion that can be engaged with the engaging portion is formed in any one of the stator, the terminal portion, and the housing, and the engagement It is preferable that the portion and the engaged portion are configured to engage only when the leaf spring member is disposed in a predetermined direction.

  According to this characteristic configuration, the engaging portion formed in the notch portion of the leaf spring member and the engaged portion formed in any one of the stator, the terminal, and the housing can be engaged with each other, The leaf spring member cannot be disposed. Accordingly, the leaf spring member can be reliably disposed in a predetermined direction during assembly, and variations in characteristics among products caused by disposing the leaf spring member in different directions can be eliminated. . In particular, if such an engagement mechanism is provided on both of the leaf spring members provided at both ends of the mover, the variation between products can be eliminated for both leaf spring members, so the effect is greater. Become.

  In addition, it is preferable that one of the leaf spring members and the other notch are arranged at positions that are symmetrical in the circumferential direction.

  For example, when the cutout portion is formed unevenly in the circumferential direction, such as when the cutout portion is formed only at one location in the circumferential direction of the leaf spring member, the deformation characteristics and strength of the leaf spring member are There is a possibility that it is not necessarily uniform in the circumferential direction. For this reason, there is a possibility of inducing a problem that the moving direction of the mover is deviated from the axial direction or a problem that stress concentration is likely to occur due to the uneven distribution of strength in the circumferential direction of the leaf spring member.

  However, as in this feature configuration, one notch and the other notch of the two leaf spring members disposed at both ends in the axial direction of the mover are positioned symmetrically in the circumferential direction. When arranged, when the two leaf spring members are regarded as one spring mechanism, the characteristics of the spring mechanism are uniform in the circumferential direction. Therefore, it is possible to suppress the movement direction of the mover from the axial direction, and it is possible to reduce the stress concentration generated due to the uneven strength of the leaf spring member in the circumferential direction.

  The leaf spring member is formed with a plurality of connecting portions that connect the central portion and the peripheral portion in the same shape and in the circumferential direction, and the connecting portions are arranged in order from the central portion side. A first arc region; a second arc region having a larger curvature than the first arc region; and a third arc region having a smaller curvature than the second arc region; Preferably, the third arc region is formed.

  According to this characteristic configuration, the curvature of the first arc region connected to the central portion and the third arc region connected to the peripheral portion is smaller than the curvature of the second arc region located between these regions. Since the curvature of the first arc region is relatively small, stress concentration at the central portion of the leaf spring member where the base end portions of the connecting portions gather can be alleviated. In addition, since the third arc region having a relatively small curvature is formed at the position facing the notch, it is easy to form the connection portion while avoiding the notch. Furthermore, since the second arc region having a relatively large curvature exists between the first arc region and the third arc region, even if the curvatures of the first arc region and the third arc region are made as small as possible, the entire connecting portion Accordingly, the leaf spring member can be reduced in size.

  In addition, it is preferable that a plurality of the notch portions are formed uniformly in the circumferential direction so as to correspond to the plurality of connection portions.

  For example, when a plurality of connection portions are formed on the leaf spring member, but only one notch portion is formed, the deformation characteristics and strength of the connection portion existing in the vicinity of this one notch portion are reduced. There is a possibility that the deformation characteristics and strength of other connecting portions are different. Therefore, as in this feature configuration, if a plurality of notches are formed uniformly in the circumferential direction so as to correspond to a plurality of connecting portions, the deformation characteristics and strength of each connecting portion can be made equal. As a result, the characteristics of the leaf spring member can be made uniform in the circumferential direction, and it can be avoided that different loads act on only some of the connecting portions.

It is sectional drawing of the linear actuator which concerns on this invention. It is a disassembled perspective view of the linear actuator which concerns on this invention. It is a top view which shows the shape of a leaf | plate spring member. It is a top view which shows the shape of the leaf | plate spring member which concerns on another embodiment.

  Embodiments of a linear actuator according to the present invention will be described below with reference to the drawings. For example, this linear actuator is provided in the vicinity of a vibration source of an automobile and generates vibration that cancels out vibration transmitted from the vibration source, thereby reducing vibration and noise in the passenger compartment. It can be used as a container.

  FIG. 1 is a cross-sectional view showing the overall structure of the linear actuator 1, and FIG. 2 is an exploded perspective view of the linear actuator 1. The linear actuator 1 is covered with a housing 10 made of a magnetic metal such as iron or magnetic stainless steel. As shown in FIGS. 1 and 2, the housing 10 has a three-stage configuration including a first step portion 10a, a second step portion 10b, and a third step portion 10c in order from the top in the drawing. Each step portion has a cylindrical shape as a basic shape, and the first step portion 10a has the smallest diameter and the third step portion 10c has the largest diameter. However, in order to provide a space in which the terminal portion 24 described later is provided, a part of the first step portion 10a in the circumferential direction is configured to have a diameter equivalent to the diameter of the second step portion 10b. For this reason, the cross section of the 1st step part 10a does not become an exact circle. A shoulder portion 10d formed by a difference in diameter between the first step portion 10a and the second step portion 10b functions as a portion for locking a stator 20 described later. Further, an opening 10e for connecting a connector 50 described later is formed on the upper surface of the first step portion 10a.

  The cylindrical space 11 inside the second step portion 10b corresponds to the “tubular space” in the present invention. An annular stator 20 including a coil 21 is fixed to the outer peripheral surface of the cylindrical space 11, in other words, the inner peripheral surface of the second step portion 10 b that defines the cylindrical space 11. The stator 20 includes a resin bobbin 22 around which the coil 21 is wound and a tooth 23 made of a magnetic metal that fixes the bobbin 22. A first protrusion 23 a is formed on the peripheral edge of the tooth 23 so as to protrude on both sides in the direction along the axis O of the stator 20, and on the inner peripheral side of the first protrusion 23 a than the first protrusion 23 a. A second protrusion 23b with a small protrusion is formed. The upper first protrusion 23 a in the drawing contacts the shoulder 10 d of the housing 10, and the lower first protrusion 23 a in the drawing contacts a ring member 25, which will be described later, thereby the stator 20 of the housing 10. It is fixed to the inner peripheral surface of the second step portion 10b.

  The linear actuator 1 has a shaft member 33 coaxially with the axis O of the stator 20. A permanent magnet 31 and a pair of yokes 32 that sandwich the permanent magnet 31 in the axial direction are attached to the shaft member 33. The permanent magnet 31 and the pair of yokes 32 are collectively referred to as a mover 30. A pair of metal leaf spring members 40 are disposed at both ends in the axial direction of the mover 30. Thereafter, when the pair of leaf spring members 40 are shown separately, those disposed on the distal end side (the upper side in FIG. 1) of the shaft member 33 are the distal end side leaf spring member 40A and the proximal end side of the shaft member 33 ( A member disposed on the lower side of FIG. 1 is referred to as a proximal end leaf spring member 40B.

  Insertion holes 31a, 32a, and 40a having diameters equivalent to the shaft diameter of the shaft member 33 are formed in the central portions of the permanent magnet 31, the yoke 32, and the leaf spring member 40, and the insertion holes 31a, 32a, 40a are formed in the respective insertion holes 31a, 32a, 40a. The shaft member 33 is inserted. Further, the shaft member 33 has a large-diameter portion 33 a having a shaft diameter larger than the shaft diameter of the portion inserted through the permanent magnet 31, the yoke 32, and the leaf spring member 40. The proximal-side leaf spring member 40B is locked to the flange portion of the large-diameter portion 33a, and the nut 34 is screwed into the screw portion 33b formed at the distal end portion of the shaft member 33, so that the large diameter of the shaft member 33 is obtained. The permanent magnet 31, the yoke 32, and the leaf spring member 40 are fixed to a portion between the portion 33a and the screw portion 33b.

  In order to fix the stator 20 to the inner peripheral surface of the second step portion 10 b of the housing 10, an annular ring member 25 is used. The ring member 25 is made of metal, and is fixed by a method such as press fitting or caulking from the proximal end side (lower side in FIG. 1) of the shaft member 33 to the inner peripheral surface of the second stepped portion 10b. By providing such a ring member 25, the stator 20 is fixed between the shoulder 10 d of the housing 10 and the ring member 25. Further, the peripheral edge portion of the distal side leaf spring member 40A is locked between the shoulder portion 10d of the housing 10 and the second protruding portion 23b of the tooth 23, and the peripheral edge portion of the proximal side leaf spring member 40B is connected to the ring member 25 and the second portion. It is latched between the protrusion 23b.

  With the above configuration, the center portion of the leaf spring member 40 is fixed to the movable element 30 side, and the peripheral edge portion is fixed to the stator 20 side. A gap is provided between the stator 20 and the mover 30, and when the coil 21 is energized, the mover 30 vibrates in the axial direction while receiving the biasing force of the leaf spring member 40. The leaf spring member 40 has a role of efficiently vibrating the mover 30 in a specific frequency region using its resonance characteristics and holding the position of the mover 30 when not energized.

  A terminal portion 24 extending along the shaft core O from a part of the end portion is provided at an end portion (upper end portion in FIG. 1) in the axial direction of the stator 20. Here, the terminal portion 24 is integrally formed with the bobbin 22 of the stator 20 by resin molding. However, the stator 20 and the terminal portion 24 may be configured separately. The terminal portion 24 is electrically connected to the connector 50 disposed in the opening 10 e of the housing 10, so that power can be supplied to the coil 21 from a power supply source (not shown) via the connector 50 and the terminal portion 24. Become.

  In order to avoid interference with the terminal portion 24, as shown in FIG. 3, a cutout portion 40 b formed by cutting a circular portion with a straight string is formed on a part of the peripheral portion of the leaf spring member 40. Provided. The leaf spring member 40 is produced, for example, by press punching. In the present embodiment, since the distal end side leaf spring member 40A and the proximal end side leaf spring member 40B have the same shape, a plurality of press dies are not required, and the number of components can be reduced by sharing components. Is preferred. Since the notch 40b is formed in the tip side leaf spring member 40A, the terminal portion 24 can be connected to the connector 50 so as not to interfere with the tip side leaf spring member 40A. As a result, since the winding of the coil 21 can be connected to the terminal portion 24 extending in the axial direction, it is possible to avoid an increase in the radial dimension of the linear actuator 1. Further, when the notch 40b is in contact with the terminal portion 24, it is possible to prevent the tip side leaf spring member 40A from rotating darkly when the nut 34 is screwed, and quick assembly is possible.

  The front side leaf spring member 40A is formed with a concave engaging portion 40c at a position that is asymmetric with respect to the center line C of the notch 40b, and the terminal portion 24 is formed with a convex shape that can be engaged with the engaging portion 40c. An engaged portion 24a is formed. According to such an engagement mechanism, the tip side leaf spring member 40A can be arranged in the direction shown in FIG. 3, but when the front and back sides of FIG. 3 are reversed, the engagement portion 40c and the engaged portion 24a cannot be engaged and cannot be disposed. Therefore, the tip side leaf spring member 40A can be reliably arranged in a predetermined direction during assembly, and the variation in characteristics between products caused by arranging the tip side leaf spring member 40A in different directions depending on the product is eliminated. can do. The engaged portion 24a may be formed in the housing 10.

  Furthermore, if the above-mentioned engagement mechanism is provided also about the base end side leaf | plate spring member 40B, since the dispersion | variation between products about both the leaf | plate spring members 40 can be eliminated, the effect becomes larger. In the present embodiment, as shown in FIG. 2, a convex engaged portion 26a is formed on the protruding portion 26 of the bobbin 22 that partially protrudes in the axial direction from the tooth 23, and this is a proximal end leaf spring member 40B. The engaging portion 40c can be engaged. The engaged portion 26a may be provided on another member constituting the housing 10 or the stator 20.

  When the cutout portion 40b is formed non-uniformly in the circumferential direction, such as when the cutout portion 40b is formed only at one place on the circumference as in this embodiment, the deformation characteristics of the leaf spring member 40 There is a possibility that the strength and the strength are not necessarily uniform in the circumferential direction. For example, in the vicinity of the cutout portion 40b of the leaf spring member 40, there is a possibility that problems such as weakness compared to other portions, a large deformation amount, and a large stress concentration may occur. Therefore, as shown in FIG. 2, it is preferable to arrange the notch 40b of the distal end side leaf spring member 40A and the notch 40b of the proximal end side leaf spring member 40B at symmetrical positions in the circumferential direction. Then, when the two leaf spring members 40 are regarded as one spring mechanism, the characteristics of the spring mechanism are uniform in the circumferential direction. Therefore, it is possible to suppress the movement direction of the mover 30 from deviating from the axial direction, and it is possible to reduce the stress concentration generated due to the uneven strength of the leaf spring member 40 in the circumferential direction.

  As shown in FIG. 3, the leaf spring member 40 is formed to include three connection portions 41 that connect the central portion and the peripheral portion. Each connecting portion 41 has a shape that curves counterclockwise from the central portion to reach the peripheral portion, and each connecting portion 41 is arranged in the same shape and at equal intervals in the circumferential direction. The connecting portion 41 includes a first arc region 41a, a second arc region 41b, and a third arc region 41c from the central portion toward the peripheral portion. The curvature of the second arc region 41b is larger than the curvatures of the first arc region 41a and the third arc region 41c. Moreover, the connection part 41 is formed so that the 3rd circular arc area | region 41c may be located in the position facing the notch part 40b.

  When the curvature of the first arc region 41a is made relatively small, stress concentration at the central portion of the leaf spring member 40 where the base end portions of the connection portions 41 gather can be relaxed. Further, since the third arc region 41c having a relatively small curvature is formed at a position facing the notch 40b, it is easy to form the connecting portion 41 while avoiding the notch 40b. Further, since the second arc region 41b having a relatively large curvature exists between the first arc region 41a and the third arc region 41c, it is assumed that the curvatures of the first arc region 41a and the third arc region 41c are made as small as possible. In addition, the radius of curvature over the entire connecting portion 41 can be reduced, and the leaf spring member 40 can be downsized.

[Another embodiment]
Another embodiment according to the present invention will be described with reference to FIG. In FIG. 4A, the shape of the notch 40b of the leaf spring member 40 is different from that of the above embodiment. In the above embodiment, the cutout portion 40b is formed by cutting a part of a circle with a straight string. However, in this embodiment, a concave cutout portion 40b is formed on a part of the circular peripheral edge. Yes. By making the notch 40b concave, more of the base material portion of the leaf spring member 40 can be left, and the strength of the leaf spring member 40 can be improved. Further, if the center line C of the notch 40b is formed asymmetrically so as not to pass through the center of the leaf spring member 40, the orientation of the leaf spring member 40 can be uniquely determined without providing an engagement mechanism. Can be prescribed.

  In the embodiment shown in FIG. 4b, the cutouts 40b similar to the leaf spring member 40 shown in FIG. 3 are equally arranged one by one every 120 degrees in the circumferential direction. For example, when a plurality of connection portions 41 are formed on the leaf spring member 40 as shown in FIG. 3 but only one cutout portion 40b is formed, it exists in the vicinity of this single cutout portion 40b. There is a possibility that the deformation characteristics and strength of the connecting portion 41 to be performed are different from the deformation characteristics and strength of the other connecting portions 41. Therefore, as in this embodiment, if the plurality of notches 40b are formed uniformly in the circumferential direction so as to correspond to the plurality of connecting portions 41, the deformation characteristics and strength of each connecting portion 41 can be made equal. . As a result, the characteristics of the leaf spring member 40 can be made uniform in the circumferential direction, and it can be avoided that different loads act only on some of the connection portions 41.

  In addition, the shape of the leaf | plate spring member 40 is not restricted to what was shown above. For example, the number of connection portions 41 is not limited to three, and may be two, or four or more. Further, the basic shape of the leaf spring member 40 may be an ellipse or a polygon, and the tip side leaf spring member 40A and the base end side leaf spring member 40B may have different shapes. Furthermore, it is not an essential requirement of the present invention to provide the notch 40b in the base end side leaf spring member 40B.

  The present invention includes an annular stator that is fixed with a coil, a movable element that has a permanent magnet and is arranged coaxially with the axis of the stator and is movable in the axial direction with respect to the stator, The present invention can be applied to a linear actuator provided with a leaf spring member disposed between a stator and a mover.

1 Linear actuator 10 Housing 11 Cylindrical space (tubular space)
DESCRIPTION OF SYMBOLS 20 Stator 21 Coil 24 Terminal part 24a Engagement part 30 Movable element 31 Permanent magnet 33 Shaft member 40 Leaf spring member 40b Notch part 40c Engagement part 41 Connection part 41a 1st circular arc area 41b 2nd circular arc area 41c 3rd circular arc Area O Axle

Claims (5)

An annular stator fixed with a coil on the inner peripheral surface of the housing having a cylindrical space inside;
A permanent magnet attached to a shaft member arranged coaxially with the axis of the stator; and a mover movable in the axis direction relative to the stator;
A terminal portion extending in the axial direction from a part of an end of the stator in the axial direction, and connecting the coil to an external power supply source;
A leaf spring member disposed at both ends in the axial direction of the mover, at least a part of the peripheral edge portion being fixed to the stator side, and a center portion being fixed to the mover side; Prepared,
A linear actuator in which a notch for preventing interference with the terminal portion is formed in a peripheral portion of the leaf spring member.   An engaging portion is formed in the notch, and an engaged portion that can be engaged with the engaging portion is formed in any of the stator, the terminal portion, and the housing, and the engaging portion and the The linear actuator according to claim 1, wherein the engaged portion is configured to engage only when the leaf spring member is disposed in a predetermined direction.   3. The linear actuator according to claim 1, wherein one of the leaf spring members and the other notch are arranged at positions that are symmetrical in the circumferential direction. In the leaf spring member, a plurality of connection portions that connect the central portion and the peripheral portion are formed in the same shape and in the circumferential direction,
The connecting portion includes a first arc region, a second arc region having a larger curvature than the first arc region, and a third arc region having a smaller curvature than the second arc region in order from the central portion side. And
The linear actuator according to any one of claims 1 to 3, wherein the third arc region is formed at a position facing the notch.   The linear actuator according to claim 4, wherein a plurality of the cutout portions are formed uniformly in the circumferential direction so as to correspond to the plurality of connection portions.

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