JP5573002B2 - Linear actuator - Google Patents

Description

  The present invention relates to a linear actuator.

  Conventionally, a linear actuator is known in which a fixed portion and a movable portion are arranged on the same axis, and the movable portion is configured to reciprocate along the axial direction (thrust direction) with respect to the fixed portion. The type in which the movable part is arranged around (outside) the fixed part is called the outer movable linear actuator, and the present applicant has also proposed various outer movable linear actuators that can achieve high performance and miniaturization. (For example, see Japanese Patent Application No. 2009-071553, Patent Document 1).

JP 2007-135350 A

  By the way, this type of linear actuator may not perform its intended function or may fail to operate when a foreign substance such as water or a liquid such as beverage or a foreign substance enters inside. Therefore, a mode in which the outer movable linear actuator is housed in a dedicated case and the entire linear actuator is covered is conceivable.

  However, when such an aspect is adopted, while the drip-proof property and the dust-proof property can be obtained, there arises a problem that the size and the price are increased. Furthermore, the enlargement of the dedicated case also increases the weight, resulting in a linear actuator that is inferior in handleability during installation or maintenance.

  The present invention has been made paying attention to such problems, and its main purpose is to demonstrate appropriate waterproof function, drip-proof function and dust-proof function while avoiding enlargement and significant cost increase. It is an object of the present invention to provide a linear actuator capable of satisfying the requirements.

That is, the linear actuator of the present invention includes a fixed portion disposed on the same axis and a movable portion that can reciprocate in the axial direction with respect to the fixed portion, the movable portion is disposed outside the fixed portion, An outer movable linear actuator that can be attached to one of the surfaces to be attached. The outer movable linear actuator includes a cover that covers an end surface on the opposite side of both axial end surfaces, and the cover is attached to the movable part . The end face on the mounting side is the end face that is not covered with the cover, and the gap formed between the inward face of the movable part and the outward face of the fixed part that are opposite to each other is covered with the cover of the axial end faces. It is characterized in that it communicates with the external space at the end face on the mounting side that is not broken. Here, “covering the end face” means to completely cover the end face or substantially completely cover the end face (covering except for a part thereof).

  With such a linear actuator, it is possible to reduce the size and cost as compared with a mode in which the entire linear actuator is covered with a dedicated case, and liquid or foreign matter can enter the linear actuator from the direction opposite to the mounting side. Intrusion can be suitably prevented. Furthermore, since the linear actuator according to the present invention has the cover attached to the movable part, a problem that may occur when the cover is attached to the fixed part, that is, an increase in size and cost due to the cover covering the fixed part and the movable part. The trouble of doing can be avoided. Further, since the linear actuator according to the present invention is an outer movable linear actuator in which the above-described cover is attached to the movable part, the cover itself that follows the reciprocating motion of the movable part can be regarded as a part of the movable part. By adjusting the weight of the cover, the weight of the entire movable part can be easily adjusted.

  ADVANTAGE OF THE INVENTION According to this invention, the linear actuator which can exhibit an appropriate waterproof function, a drip-proof function, and a dust-proof function can be provided, avoiding enlargement and a significant cost increase.

1 is an overall perspective view of a linear actuator according to a first embodiment of the present invention. The disassembled perspective view of the linear actuator which concerns on the same embodiment. The principal part disassembled perspective view of the linear actuator which concerns on the same embodiment. The principal part front view of the linear actuator which concerns on the same embodiment. The schematic cross section of the linear actuator which concerns on the same embodiment. The whole perspective view of the modification of the linear actuator which concerns on the embodiment. The schematic cross section of the linear actuator which concerns on the modification.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings. The linear actuator 1 according to this embodiment is an outer movable linear actuator in which a movable portion 3 is disposed around (outside) the fixed portion 2 as shown in FIGS.

  The fixed portion 2 includes a stator (inner core) 21, a bobbin 22 that can cover the stator 21, a permanent magnet 23 disposed on the upper end surface and the lower end surface of the stator 21 that is not covered by the bobbin 22, and a bobbin 22 is provided with a coil 24 wound around the outer periphery of 22 and a shaft 25 disposed in the center. The axial direction of the shaft 25 and the direction in which the movable part 3 reciprocates, that is, the thrust direction, are the same direction, and the axial direction of the shaft 25 and the thrust direction used in the following description are synonymous. Further, in the following description, “front” means a direction seen from the axially opposite side of the shaft 25 (the cover 7 side described later).

  As shown in FIGS. 2 to 5, the stator 21 is made of, for example, a thin steel plate (for example, a silicon steel plate) laminated in the thrust direction, and the shaft 25 can be inserted into the center portion. A shaft insertion hole 211 is provided. In the present embodiment, a shaft insertion hole 211 whose opening shape is a square shape is applied (see FIGS. 2 to 4). In addition, the stator 21 forms a permanent magnet set portion 212 on which the permanent magnets 23 can be disposed on the upper end surface and the lower end surface facing each other across the shaft insertion hole 211. The permanent magnet set part 212 is formed by a flat flat surface.

  As shown in FIGS. 2 and 5, the bobbin 22 (insulator) is composed of a bobbin unit 22U divided into two in the thrust direction (the bobbin 22 is omitted in FIGS. 3 and 4), and the bobbin unit 22U The stator 21 and the permanent magnet 23 are sandwiched from both axial ends of the shaft 25 so that the entire stator 21 and a part of the permanent magnet 23 can be covered. The bobbin 22 has a shaft insertion hole 221 through which the shaft 25 can be inserted, and a pair of upper and lower coil winding recesses 222 around which the coil 24 can be wound. The shaft insertion hole 221 formed in the bobbin 22 is a round hole that communicates with the shaft insertion hole 211 formed in the stator 21 and is slightly larger than the shaft insertion hole 211, and the spacer S can be fitted into the round hole. It is set as follows.

  As shown in FIGS. 2 to 5, the permanent magnets 23 are respectively disposed in a pair of permanent magnet set portions 212 in the stator 21. A plurality (two in the illustrated example) of permanent magnets 23 are arranged side by side along the axial direction of the shaft 25 in each permanent magnet set portion 212. And in this embodiment, the permanent magnet 23 which makes flat form is applied. Accordingly, the surfaces of the plurality of permanent magnets 23 having a flat plate shape fixed to each permanent magnet set portion 212 which is a flat flat surface are flush or substantially flush.

  The shaft 25 is attached by being inserted into a shaft insertion hole 221 in the bobbin 22 and a shaft insertion hole 211 in the stator 21 as shown in FIGS. In the present embodiment, the shaft 25 having an outer shape corresponding to the opening shape of the shaft insertion hole 211 formed in the stator 21, that is, the shaft 25 whose outer edge shape in the cross section is a square shape or a substantially square shape is applied. . A concave portion 251 extending along the axial direction is formed at both ends of the shaft 25, and a female screw portion is formed on the inner peripheral surface of the concave portion 251. And it is comprised so that the volt | bolt B1 can be screwed to each internal thread part, respectively (refer FIG. 5).

  As shown in FIGS. 2 to 5, the coil 24 is wound around each coil winding recess 222 in the bobbin 22, and is connected so that current flows through the upper part and the lower part across the shaft 25. . And the movable part 3 demonstrated below can be reciprocated by switching the direction through which an electric current flows.

  As shown in FIGS. 2 and 5, the movable portion 3 has a substantially rectangular tube shape in which a movable element (outer core) 31 as a movable magnetic pole and a movable spacer 32 are overlapped in the thrust direction. In the present embodiment, the movable portion 3 having a substantially rectangular tube shape is applied by mutually assembling the movable portion unit 3U formed by dividing the movable element 31 and the movable spacer 32 into two parts in the vertical direction. You may apply the movable part which uses the needle | mover and the movable spacer which are not.

  As shown in FIGS. 2 to 5, the mover 31 is formed by laminating and bonding thin steel plates (for example, silicon steel plates) in the thrust direction. The surface of the mover 31 that swells toward the permanent magnet 23 relative to the movable spacer 32 and faces the permanent magnet 23 functions as the magnetic pole surface 311, and the magnetic pole surface 311 is parallel to the permanent magnet 23. It is set on a flat flat surface. As a result, a gap G having a predetermined dimension extending linearly is formed between the inward surface of the movable element 31 and the outward surface of the stator 21, that is, between the magnetic pole surface 311 and the permanent magnet 23. (See FIG. 4).

  The movable part 3 formed by integrally assembling the movable element 31 and the movable spacer 32 has a pair of upper and lower portions penetrating the movable element 31 and the movable spacer 32 in the thrust direction at the center in the width direction at the upper end and the lower end. Parallel pins 33 are provided, and both end portions of the parallel pins 33 protrude in the thrust direction from the movable spacers 32, respectively. In addition, bolt insertion holes 3a penetrating in the thickness direction are formed at four corners of the movable portion 3 having a rectangular shape in front view (see FIG. 2).

  The movable part 3 having such a configuration is coupled to the fixed part 2 via a bearing 4 in this embodiment. In the linear actuator 1, in a state where the movable portion 3 is connected to the fixed portion 2 via the bearing 4, the shaft 25 is moved by the magnetic force generated from the permanent magnet 23 when the coil 24 is not energized. Held in place with respect to the child 31). When the coil 24 is energized, the movable part 3 reciprocates in the thrust direction along the shaft 25 based on the magnetic field generated by the current flowing in the coil 24 and the direction of the magnetic field generated from the permanent magnet 23.

  The bearing 4 connects the fixed part 2 and the movable part 3 on the same axis, and supports the movable part 3 so as to reciprocate with respect to the fixed part 2 by elastically deforming itself. This is constituted by a single plate spring 41. As shown in FIGS. 2 to 5, the leaf spring 41 includes a frame portion 411 having a frame shape superimposed on the movable spacer 32 in the movable portion 3 and a flexible portion 412 provided inside the frame portion 411. It is a thin plate provided integrally. The leaf spring 41 is formed by punching, for example. Bolt insertion holes 411a penetrating in the thickness direction are formed at the four corners of the frame portion 411 having a substantially rectangular shape when viewed from the front, and the frame portion 411 of the leaf spring 41 is sandwiched between the flange member 5 and the movable portion 3. It is. Further, an upper opening 411b and a lower opening 411c that open upward or downward are formed at the center in the width direction at the upper and lower ends of the frame portion 411, and both end portions of the parallel pins 33 provided on the movable portion 3 are formed at these ends. It is set so that it can be fitted into the upper opening 411b and the lower opening 411c. The flexible portion 412 has a shape of approximately 8 in front view, and has a shaft insertion hole 412a through which the shaft 25 can be inserted at the center. The shaft insertion hole 412a can communicate with the shaft insertion hole 211 formed in the stator 21 and the shaft insertion hole 221 formed in the bobbin 22. In this embodiment, the opening shape of the shaft insertion hole 412a is changed to the stator 21. The shape is set to be the same or substantially the same as the opening shape of the shaft insertion hole 211 formed in the above, that is, a rectangular shape or a substantially rectangular shape (see FIGS. 2 to 4). Of the leaf spring 41, the central portion of the flexible portion 412 is sandwiched between the spacers S, and the frame portion 411 is sandwiched between the movable portion 3 (specifically, the movable spacer 32) and the flange member 5. .

  As shown in FIGS. 2 and 5, the flange member 5 has substantially the same frame shape as the frame portion 411 of the leaf spring 41, and has bolt insertion holes 51 formed in the four corners in the thickness direction, and upper and lower end portions. It has a recess 52 provided at the center in the width direction and capable of accommodating the end of the parallel pin 33 with some play in the thrust direction.

  And the linear actuator 1 which concerns on this embodiment is as shown in FIG.1, FIG.2 and FIG.5. The attaching part (base) which can be attached to an attachment object to one end surface side among the axial direction both end surfaces of the shaft 25. 6 and a cover 7 covering the other end surface is disposed on the other end surface (the end surface on the side opposite to the attachment).

  The cover 7 has a plate shape having the same or substantially the same outer shape as the flange member 5 and the movable portion 3 (movable element 31). The cover 7 has a bolt insertion hole 71 formed in the four corners and penetrating in the thickness direction, and a shaft insertion hole 72 penetrating in the thickness direction formed in the central portion. The shaft insertion hole 72 has an opening shape that is slightly larger than the outer shape of the portion corresponding to the head portion of the shaft 25 (the spacer S positioned in the vicinity of the end portion of the shaft 25 in this embodiment). In the present embodiment, the head of the shaft 25 (specifically, the spacer S positioned near the end of the shaft 25) is set slightly out of the shaft insertion hole 72. The range is regulated.

  The linear actuator 1 having such a configuration inserts the shaft 25 having a substantially quadrangular prism shape into the shaft insertion hole 412a in the plate spring 41 opened in a corresponding quadrangular shape, so that the shaft 25 is moved with respect to the plate spring 41. It is supported in a state in which it cannot rotate around the axis. Further, by inserting the shaft 25 into the shaft insertion hole 221 in the bobbin 22 and the shaft insertion hole 211 in the stator 21, the entire fixing portion 2 including the stator 21 does not tilt around the shaft 25. . And the relative position of the movable part 3 and the fixed part 2 can be positioned on the basis of a pair of leaf springs 41 arranged at positions that can be sandwiched in the axial direction of the shaft 25. Specifically, the movable unit 3U divided into two parts in the vertical direction is brought close together so as to sandwich the fixed part 2 from the vertical direction, and one parallel pin 33 of the pair of upper and lower parallel pins 33 provided in the movable part 3 is The other parallel pin 33 is inserted into the lower opening 411 c of the frame portion 411 while being inserted into the upper opening 411 b of the frame portion 411. Both ends of the parallel pins 33 are accommodated in the recesses 52 in the pair of flange members 5 arranged at positions where the fixed portion 2 and the pair of leaf springs 41 can be sandwiched in the axial direction of the shaft 25 (FIGS. 2 and 5). reference). Subsequently, the bolt B2 is inserted into the bolt insertion hole 71 of the cover 7 that communicates in the thrust direction, the bolt insertion hole 51 of the flange member 5, the bolt insertion hole 411a of the leaf spring 41, and the bolt insertion hole 3a of the movable portion 3. By fastening the distal end portion of B2 to a nut (not shown), the linear actuator 1 in which the cover 7, the flange member 5, and the leaf spring 41 are assembled together is obtained.

  The outer movable type linear actuator 1 assembled in this way is covered with a cover 7 on the end surface opposite to the end surface on which the mounting portion 6 is provided (the end surface on the opposite side) of the shaft 25 in the axial direction. Therefore, it is possible to prevent liquid, foreign matter and the like from entering the linear actuator 1 from the side where the cover 7 is disposed. As a result, it is possible to avoid the occurrence of malfunction due to the entry of liquid or foreign matter into the linear actuator 1, and the linear actuator 1 is excellent in reliability. Further, since the linear actuator 1 according to the present embodiment has the cover 7 attached to the movable part 2 (via the leaf spring 41), a problem that may occur when the cover 7 is attached to the fixed part 2, that is, the fixed part. 2 and a large cover that covers the movable part 3 can be solved. In addition, the linear actuator 1 according to the present embodiment is provided with a cover 7 that shields the inside of the linear actuator 1 and prevents access to the inside of the linear actuator 1, so that the fingers of workers and users can be placed inside the linear actuator 1. It is possible to prevent contact with the actuator, prevent injury to workers and users, and inadvertent access to the linear actuator 1 to prevent damage to internal components of the linear actuator 1. It is excellent in handleability. In addition, the linear actuator 1 according to the present embodiment can be reduced in size and cost as compared with an aspect in which the entire linear actuator is covered with a dedicated case.

  The linear actuator 1 having such effects is excellent in versatility and installation flexibility, and can be applied to, for example, a vehicle body damping mechanism. Recently, in the automobile industry, due to environmental problems, measures to reduce the weight of the vehicle body, reduce the idling speed, or improve the cylinder deactivation engine, etc., are being promoted. It can worsen the comfort. Therefore, an active mass damper (vibration control) that actively drives a weight (weight) arranged at an appropriate location of the vehicle body by the linear actuator 1 according to the present embodiment and uses the reaction force to suppress vehicle body vibration. By adopting the mechanism, the vibration of the vehicle body can be suitably suppressed. And since the linear actuator 1 which concerns on this embodiment has attached the cover 7 to the movable part 2, the cover 7 itself functions as a part of weight (weight), and a weight (by adjusting the weight of the cover 7 ( Weight) The total weight can be easily adjusted. Furthermore, the linear actuator 1 according to the present embodiment can shield the electromagnetic wave emitted from the coil 24 or the electromagnetic wave acting on the linear actuator 1 from the outside by the cover 7. That is, the cover 7 can improve EMC (Electro-Magnetic Compatibility).

  In addition, the linear actuator 1 according to the present embodiment positions the spacer S positioned in the shaft insertion hole 72 of the cover 7 by positioning the portion corresponding to the head of the shaft 25, specifically, the vicinity of the end of the shaft 25. The shaft insertion hole 7 can be made to function as a stopper for regulating the movement range of the shaft 25 (movement range in the radial direction of the shaft 25) in a front view.

  In addition, this invention is not limited to embodiment mentioned above. For example, in the above-described embodiment, the shaft insertion hole 72 formed in the cover 7 may be covered with a covering material (not shown) that covers the movement of the movable portion 2 without obstructing it. Examples of the covering material include a waterproof sheet and an elastically deformable sheet. When an elastically deformable sheet (for example, a rubber sheet) is applied as the covering material, even when the covering material is in contact with the movable portion 2 that reciprocates, the movement of the movable portion 2 is suitably performed by elastic deformation. It can absorb and does not hinder the reciprocating motion of the movable part 2.

  In the above-described embodiment, the mode in which the shaft insertion hole 72 into which the shaft 25 can be inserted is formed in the cover 7 is exemplified. However, a cover that does not have such a shaft insertion hole may be applied. As an example, as shown in FIG. 6 and FIG. 7, other parts of the cover 7 ′ that can interfere with the head portion of the shaft 25 or the portion corresponding to the head portion of the shaft 25 (the countersunk screw B 1 ′ in the illustrated example) A cover 7 ′ having a protruding portion 72 ′ that protrudes in a direction away from the head of the shaft 25 rather than the portion of the shaft 25 is mentioned. Further, a portion of the cover 7 ′ provided on the edge of the concave portion 721 ′ inevitably formed in the portion where the protruding portion 72 ′ is formed, corresponding to the head portion 25 of the shaft or the head portion of the shaft 25 (illustrated example). Then, if the spacer S ′) is set so as to be in contact or close, the movement range of the shaft 25 (movement range in the radial direction of the shaft 25) in the front view can be regulated. 6 and 7, members and parts corresponding to the embodiment described above are denoted by the same reference numerals.

  Moreover, when applying the cover which does not have a shaft insertion hole, you may arrange | position a shock absorbing material in the site | part which can interfere with the head or the part corresponded to a head. For example, in the case of applying the cover 7 ′ shown in FIGS. 6 and 7, if the cushioning material is disposed in the recess 721 ′, a good mounting state of the cushioning material can be maintained. The cushioning material is preferably elastically deformable (for example, made of rubber).

  In the above-described embodiment, a flat permanent magnet is applied and a parallel gap extending linearly is formed between the permanent magnet and the magnetic pole surface. And the magnetic pole surface may be set to a partial arc shape corresponding to the permanent magnet. Of course, a cylindrical or substantially cylindrical shape may be applied as the shaft. In this case, the opening shape of each shaft insertion hole may be a circular shape corresponding to the outer shape of the shaft.

  Further, in the above-described embodiment, a permanent magnet type iron core movable motor, that is, a so-called reciprocating motor is illustrated as an example of the linear actuator. However, the linear actuator according to the present invention is applied to a moving magnet type that is another small stroke linear actuator. However, the same effect can be obtained.

  In addition, the specific configuration of each part is not limited to the above embodiment, and various modifications can be made without departing from the spirit of the present invention.

DESCRIPTION OF SYMBOLS 1 ... Linear actuator 2 ... Fixed part 3 ... Movable part 7, 7 '... Cover

Claims (1)

A fixed portion disposed on the same axis and a movable portion capable of reciprocating in the axial direction with respect to the fixed portion, the movable portion being disposed outside the fixed portion, It is a linear actuator that can be attached to the mounting object on the end face side,
Provided with a cover that covers the end face on the opposite side of the axial end faces, the cover is attached to the movable part, the end face on the mounting side of the axial end faces is an end face that is not covered with the cover,
The gap formed between the outwardly facing surface of the inwardly facing surface of the movable portion facing each other and the fixed part, communicates with the outside space at the end face of the mounting side which is not covered by the cover of the axial end surfaces A linear actuator characterized by

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