Linear Motor Actuator

Abstract

To provide a linear motor actuator that has a lighter movable element and improved output acceleration and response, while extending the durability of a guide mechanism.SOLUTION: A linear motor actuator with a movable yoke facing a stator includes magnets placed directly on both sides of the yoke in the thickness direction, a widthwise roller guide mechanism that supports both widthwise ends of the yoke, and a thickness direction roller guide mechanism supporting both ends of the yoke in the thickness direction, and the width direction roller guide mechanism fixes at least one width direction position of the yoke in the width direction, and the other side of the yoke in the width direction is supported such that its position in the width direction is variable.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a linear motor actuator that applies linear vibration to a test part in the direction of extension and contraction in various tests of vehicles and vehicle parts. [Background technology]

[0002] Conventionally, there has been a need for durability and performance evaluation in various tests of various vehicles and vehicle components. Such durability and performance evaluation tests are performed by linearly vibrating a test part using a vibrator, for example, a linear motor actuator. Heat generation can cause a temperature rise inside the linear motor actuator, potentially causing the yoke containing the mover to expand in the width direction. In response to this issue, Patent Document 1 describes a linear motor equipped with a structure that absorbs the thermal expansion of the yoke due to heat generation. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2003-324888 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in Patent Document 1, the thickness and space required for attaching the slide guide to the side of the mover increase the mass of the moving part, which reduces the output acceleration and responsiveness of the linear motor actuator.On the other hand, if the thickness of the mover is reduced to reduce weight, the size of the attached slide guide becomes smaller, which reduces the durability of the guide mechanism due to fretting during small vibrations, and increases the generation of vibrations and noise when the guide moves.

[0005] SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a linear motor actuator in which the movable element is made lighter, output acceleration and responsiveness are improved, and the durability of the guide mechanism is increased to extend its life. [Means for solving the problem]

[0006] In order to achieve the above object, the present invention provides a linear motor actuator having a yoke that can move while facing a stator, comprising: magnets directly arranged on both sides of the yoke in the thickness direction; width direction roller guide mechanisms that support both width direction ends of the yoke; and thickness direction roller guide mechanisms that support both thickness direction ends of the yoke, wherein the width direction roller guide mechanisms fix the position of at least one width direction of the yoke in the width direction, and support the other width direction of the yoke so that the position in the width direction is variable. [Effects of the Invention]

[0007] According to the above configuration, it is possible to improve the output acceleration and responsiveness of the linear motor actuator while extending the durability and life of the guide mechanism. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a schematic, partially cutaway cross-sectional view of a linear motor actuator according to one embodiment of the present invention. [Figure 2] 2(a) is an enlarged view of the area enclosed by the frame IIa in FIG. 1, and FIG. 2(b) is an enlarged view of the area enclosed by the frame IIb in FIG. 2(a). [Figure 3] FIG. 3 is a schematic cross-sectional view taken along line III-III in FIG. [Figure 4] Fig. 4(a) is a partial cross-sectional view of Fig. 3 before the yoke expands in the width direction due to thermal expansion, and Fig. 4(b) is a partial cross-sectional view of Fig. 3 after the yoke expands in the width direction due to thermal expansion. Note that blocks 33 and 39 are positioned so that they do not come into contact with each other. [Figure 5] FIG. 5 is a schematic cross-sectional view of a linear motor actuator according to another embodiment of the present invention. [Figure 6] FIG. 6 is an enlarged view of the area enclosed by the box VI in FIG. [Figure 7] FIG. 7 is a schematic cross-sectional view of a conventional linear motor actuator. DETAILED DESCRIPTION OF THE INVENTION

[0009] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, the present invention is not limited to these preferred embodiments.

[0010] (Example of linear motor actuator configuration) Fig. 1 is a schematic cross-sectional view of a linear motor actuator according to one embodiment of the present invention. Fig. 2(a) is an enlarged view of the area enclosed by a frame IIa in Fig. 1, and Fig. 2(b) is an enlarged view of the area enclosed by a frame IIb in Fig. 2(a). Fig. 3 is a schematic cross-sectional view taken along line III-III in Fig. 1. The linear motor actuator 1 includes a pair of frames 10, legs 12 (see Fig. 3) disposed at both ends of the pair of frames 10 so as to form a square cross-section, stators 11 disposed on the inner surfaces of the pair of frames 10 so as to face each other, a mover 20 having a yoke 21 that is movable while facing the stator 11, width direction roller guide mechanisms 31a, 31b that fix the position of at least one side of the yoke 21 in the width direction and change the position of the other side of the yoke 21 in the width direction, and a thickness direction roller guide mechanism 37 disposed on the inner surfaces of the pair of frames 10 and supporting both thickness direction ends of the yoke 21.

[0011] (stator) The stators 11 include coils for generating a magnetic field, are arranged in the longitudinal direction, and are fixed to the frame 10 with a plurality of bolts. The stators 11 are arranged so that one stator 11 faces the other stator 11, and the mover 20 moves between the stators 11. In this embodiment, the stators 11 are fixed with bolts, but they may also be fixed with a heat-resistant adhesive or the like as long as the frame 10 and the stator 11 are fixed. A linearly moving moving field is generated by passing a driving current through the coil from a power supply unit (not shown), and the mover 20 moves linearly relative to the stator 11.

[0012] (mover) The mover 20 includes a yoke 21, a magnet 22, and backing plates 23 disposed at both widthwise and thicknesswise ends of the yoke 21. As shown in FIG. 2(b), the magnets 22 are arranged alternately along the length of the yoke 21 with different magnetic poles, and are arranged on both thicknesswise sides of the yoke 21 with their magnetic poles reversed. In this embodiment, the magnet 22a has a north pole facing the stator 11 and a south pole facing the yoke 21, while the magnet 22b has a south pole facing the stator 11 and a north pole facing the yoke 21. The backing plate 23 is made of a high-hardness material and serves as a backing plate for the roller 38 of the thicknesswise roller guide mechanism 37 (described later). This allows the contact area between the backing plate 23 and the roller 38 to withstand repeated contact over a long period of time. The backing plate 23 is sized to fit only the area in contact with the roller 38, minimizing the mass of the mover 20. While the backing plate 23 is disposed on the yoke 21 in this embodiment, this is not limiting and only the yoke 21 may be used. In this case, the yoke 21 itself must have enough hardness to withstand contact with the roller 38, so the yoke may be made of ferromagnetic carbon steel or the like.

[0013] In this way, the magnet 22 can be arranged in the mover 20 of this embodiment without considering magnetic pole saturation caused by the magnet 22, and the thickness of the yoke 21 can be minimized. Furthermore, the mass of the mover 20 can be reduced, and the output acceleration and responsiveness of the vibration operation can be improved.

[0014] (Characteristics of the cross-sectional shape of the linear motor actuator) In the present invention, the thickness direction roller guide mechanism 37 has two or three rollers 38 and blocks 39 supporting the rollers 38, and multiple rollers 38 are arranged in the longitudinal direction. The thickness direction roller guide mechanisms 37 are fixed to the frame 10 with bolts, located on the inner surface of the frame 10, and positioned in the thickness direction of the mover 20, i.e., in the vertical direction on the paper surface of FIG. 3, and abut against the backing plate 23 of the mover 20. The thickness direction roller guide mechanism 37 abuts against the mover 20 to support its position in the thickness direction, and the rollers 38 movably support the mover 20. This allows the position of the mover 20 to be supported even during vibration excitation in various tests of vehicles and vehicle components. Because the rollers 38 are not included in the mass of the mover 20, a size with a large load capacity can be used without increasing the mass of the moving part, thereby extending the life of the guide mechanism. The blocks 39 of the thickness direction roller guide mechanism 37 are located in positions where they do not come into contact with the blocks 33 of the width direction roller guide mechanisms 31a and 31b (described later).

[0015] The width-direction roller guide mechanisms 31a and 31b are provided between the leg 12 of one frame 10 and the leg 12 of the other frame 10 so as to face each other in the width direction of the mover 20. As shown in FIG. 3 , one width-direction roller guide mechanism 31a has a roller 32 that supports the mover 20, a block 33 that supports the roller 32, and a block 34 that is fixed to the inner surface of the block 33 with a bolt 33a and is fixed to the side surface of the leg 12 of the frame 10 with a bolt 34a. The roller 32 of the width-direction roller guide mechanism 31a supports the side end of the mover 20 while fixing its position in the width direction. As with the thickness-direction roller guide mechanism 37, the roller 32 is not included in the mass of the mover 20, so a size with a large load capacity can be used without increasing the mass of the mover, thereby extending the life of the guide mechanism.

[0016] The other width-direction roller guide mechanism 31b includes a roller 32 supporting the mover 20, a block 33 supporting the roller 32, a block 35 having the block 33 fixed to its inner surface with a bolt 33a and variably fixed to a side surface of the leg 12 of the frame 10 with a bolt 35a via a spring 35b, which is an elastic body, and a roller guide support 36 supporting the block 35 so as to fix the thickness and longitudinal directions of the yoke 21 and fixed to the side surface of the leg 12 of the frame 10 with a bolt 36a. As will be described in detail later, the roller 32 of the width-direction roller guide mechanism 31b supports the side end of the mover 20 while variably supporting its widthwise position. In this embodiment, a spring 35b, which is an elastic member, is provided between the block 35 and the bolt 35a to accommodate thermal expansion of the yoke 21. As a result, even if the yoke 21 expands in the width direction of the yoke 21 due to heat, a force acts from the roller 32 of the width-direction roller guide mechanism 31b toward the block 35, thereby being able to accommodate the force caused by the expansion.

[0017] Fig. 4(a) is a schematic cross-sectional view of the linear motor actuator 1 of Fig. 3 before the yoke 21 expands. In this embodiment, vibration is generated by moving the mover 20 in the longitudinal direction. At that time, the rollers 32 of the width direction roller guide mechanism 31b support the position of the mover 20 in the width direction, and the rollers 38 of the pair of thickness direction roller guide mechanisms 37 support the position of the mover 20 in the thickness direction. In this way, the mover 20 can be moved in the longitudinal direction by the width direction roller guide mechanism 31b and the pair of thickness direction roller guide mechanisms 37.

[0018] On the other hand, when the yoke 21 expands in the width direction due to thermal expansion of the movable member 20, as shown in Figure 4(b), the pair of thickness direction roller guide mechanisms 37 support the yoke 21 in the thickness direction, and the spring 35b is urged outward in the width direction via the roller 32 of the width direction roller guide mechanism 31b to absorb the thermal expansion of the blocks 33 and 35.

[0019] Furthermore, the width-direction backing plate 23 of the movable element 20 is in contact with the rollers 32 of the width-direction roller guide mechanism 31b, and the movable element 20 is supported by the thickness-direction backing plate 23 and the rollers 38 of a pair of thickness-direction roller guide mechanisms 37, so that the position of the movable element 20 can be supported.

[0020] The blocks 35 provided on the outer surfaces of the legs 12 of the frame 10 have the function of supporting the rollers 32 via the blocks 33, and are further supported in the longitudinal and thickness directions by roller guide supports 36 to reinforce the rigidity of the blocks 35. The roller guide supports 36 support the block 35 so that the position of the block 35 can be changed. In this embodiment, the roller guide supports 36 are in contact with the entire contact surface of the block 35, but as long as they can support the block 35, the roller guide supports 36 may be in contact with only a portion of the block 35.

[0021] In this way, with a structure such as width-direction roller guide mechanism 31b, even if yoke 21 thermally expands in the width direction, the spring of width-direction roller guide mechanism 31b presses it against the side surface of yoke 21 in the width direction with an appropriate pressure, and it can move mover 20 while supporting the position of mover 20 in the width direction by following the expansion and contraction of yoke 21 without letting go. Furthermore, by using an elastic member to release displacement due to thermal expansion, it is possible to prevent a large load from being applied to the rollers of the roller guide mechanism, thereby enabling a longer lifespan.

[0022] Furthermore, by moving the movable element 20 while supporting its side end portions with the rollers 32 of the width-direction roller guide mechanisms 31a, 31b, it is possible to reduce the movement noise that may be generated by the slide guide of Patent Document 1, thereby reducing the influence on the sound evaluation of the test part when testing the test part.

[0023] In this embodiment, the elastic member is a spring, but is not limited to this. For example, an elastic body such as an elastomer may be interposed between the bolt 35a and the block 35.

[0024] (Features of the load suppression roller guide mechanism of the linear motor actuator) FIG. 5 is a schematic cross-sectional view of a linear motor actuator according to another embodiment of the present invention, which is a linear motor actuator equipped with a lateral load guide mechanism. FIG. 6 is an enlarged view of the area enclosed by the box VI in FIG. 5. During various tests of vehicles and vehicle components, a lateral load may be applied in a direction perpendicular to the extension / contraction direction as a test condition for the test component, or a load may occur in the perpendicular direction due to the characteristics of the test component. The linear motor actuator 1 of the present invention receives a force in the lateral direction perpendicular to the longitudinal direction (hereinafter also referred to as a lateral load). Therefore, the linear motor actuator 1 is equipped with a detachable load suppression guide mechanism 40 (hereinafter also referred to as a lateral load suppression guide mechanism) that suppresses the lateral load. The lateral load suppression guide mechanism 40 is detachably fixed to the linear motor actuator 1 with bolts (not shown). Although the lateral load suppression guide mechanism 40 is detachable in this embodiment, it may also be configured integrally with the linear motor actuator 1.

[0025] The lateral load suppression guide mechanism 40 includes a table 41, a pair of guide shafts 42 arranged at both ends of the table 41, and a lateral load roller guide 43 fixed to the testing device frame 2.

[0026] The table 41 is connected to the tip of the mover 20 of the linear motor actuator 1, and moves in the longitudinal direction together with a pair of guide shafts 42. The table 41 is connected to a test part on the surface opposite to the surface connected to the tip of the mover 20, and transmits vibration motion to the test part.

[0027] The lateral load roller guide 43 includes two pairs of rollers 44 that sandwich the guide shaft 42 in a lateral direction perpendicular to the longitudinal direction and in a vertical direction perpendicular to the longitudinal and lateral directions. The lateral load roller guide 43 has two pairs of rollers 44 arranged at both ends in the longitudinal direction.

[0028] As shown in Figure 6, when a lateral load F1 is applied, lateral loads F2 and F3 are transmitted to each of the rollers 44 of the lateral load suppression guide mechanism 40 through the rigid guide shaft 42 of the lateral load suppression guide mechanism 40. The lateral load roller guide 43 of the lateral load suppression guide mechanism 40 then absorbs the reaction force F4 of the fixed test equipment frame 2. Because the rollers 44 of the lateral load suppression guide mechanism 40 are able to rotate even when subjected to the lateral loads F2 and F3, they do not affect the movement of the vibration excitation operation on the test part.

[0029] In this way, by absorbing F4 with the lateral load roller guide 43 of the lateral load suppression guide mechanism 40, the yoke 21 of the mover 20 of the linear motor actuator 1 is not affected by the lateral load, and therefore does not require strength to withstand the lateral load, and can be made as thin as possible. This also makes it possible for the mover 20 to be used in the form of a lightweight linear motor actuator 1 even under conditions where a lateral load is input.

[0030] (Comparison with a conventional linear motor actuator) 7 is a schematic cross-sectional view of a conventional linear motor actuator. The conventional linear motor actuator 100 is provided with a mover 104 equipped with multiple magnet plates, each of which has a magnet 103 arranged on a yoke 102, which is a common type of actuator available on the market, mounted on the side of a structure 101, and a stator 105 equipped with a coil facing the mover 104.

[0031] A conventional linear motor actuator 100 has a structure 101 for mounting a magnet plate. However, in conventional linear motor actuators, the mass of the mover 104 increases, which causes problems such as a decrease in output acceleration and responsiveness.

[0032] However, in the present invention, as a means for solving the above problem, as shown in Fig. 1 etc., magnets 22 are arranged alternately in the longitudinal direction of yoke 21 of mover 20 so that their magnetic poles are different, and by arranging them so that the magnetic poles are reversed on both sides in the thickness direction of yoke 21, it is possible to minimize the thickness in the thickness direction of yoke 21 without considering magnetic pole saturation. This makes it possible to reduce the weight of the mover without requiring a structure like in conventional linear motor actuators. [Explanation of symbols]

[0033] 1. Linear motor actuator 11 Stator 21 York 22 Magnet 31a, 31b Width direction roller guide mechanism 37 Thickness direction roller guide mechanism

Claims

1. A linear motor actuator including a yoke that is movable while facing a stator, Magnets directly disposed on both sides of the yoke in the thickness direction; a width direction guide mechanism for supporting the yoke in the width direction; a thickness direction guide mechanism for supporting the yoke in the thickness direction; a load suppression roller guide mechanism that suppresses a load generated by the movement of the yoke; Equipped with the width direction guide mechanism fixes the position of at least one of the width directions of the yoke in the width direction, and supports the other width direction of the yoke so that the position in the width direction is variable; The width direction guide mechanism has one roller guide fixed to the main body of the linear motor actuator, and the other roller guide pressed and moved by an elastic body, The load suppression roller guide mechanism comprises a block that fixes the yoke, at least one guide shaft that is fixed to the block, and at least two pairs of roller guides that support the at least one guide shaft.

2. 2. The linear motor actuator according to claim 1, wherein the magnets are arranged so that their magnetic poles are reversed on both sides of the thickness direction of the yoke.

3. 2. The linear motor actuator according to claim 1, wherein the thickness direction guide mechanism has two pairs of roller guides, each supporting both ends of the yoke in the width direction.

4. A linear motor actuator described in any one of claims 1 to 3, characterized in that it further comprises a load suppression roller guide mechanism that is detachable.

5. A linear motor actuator including a yoke that is movable while facing a stator, Magnets directly disposed on both sides of the yoke in the thickness direction; a width direction roller guide mechanism for supporting both width direction ends of the yoke; a thickness direction roller guide mechanism for supporting both ends of the yoke in the thickness direction; a load suppression roller guide mechanism that suppresses a load generated by the movement of the yoke; Equipped with the width direction roller guide mechanism fixes the position of at least one of the width directions of the yoke in the width direction, and supports the other width direction of the yoke so that the position in the width direction is variable; The load suppression roller guide mechanism comprises a block that fixes the yoke, at least one guide shaft that is fixed to the block, and at least two pairs of roller guides that support the at least one guide shaft.

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