JP2007032596A - Linear actuator, and linear actuator device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a linear actuator, and a linear actuator device capable of improving dust proofing performance and waterproofing performance, and improving rigidity, and assembly accuracy. <P>SOLUTION: The linear actuator 10 is provided with a motor part 12 having a hollow rotary shaft 13, an output screw shaft 20 inserted on an axis of the hollow rotary shaft, and a screw nut 18 arranged in the hollow rotary shaft and screwed on the output screw shaft. Rotary motion of the hollow rotary shaft is converted into linear motion of the output screw shaft via the screw nut, the hollow rotary shaft is formed as a step structure having a small diameter part 13a and a large diameter part 13b, a rotor 14 of the motor part is attached to the small diameter part, and the screw nut is arranged in the large diameter part. A stator 15 of the motor, and bearings 16, 17 rotatably supporting the hollow rotary shaft are built in along with the motor part having the hollow rotary shaft in the same case 11. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a linear actuator and a linear actuator device that convert a rotational motion of a motor unit into a linear motion and output the linear motion.

FIG. 13 is a longitudinal sectional view showing an example of a conventional linear actuator.
In this linear actuator 100, the motor unit 101 includes a hollow rotary shaft 103, a rotor 105 attached to the outer periphery of the hollow rotary shaft 103, and a stator 107 provided around the rotor 105. The hollow rotating shaft 103 rotates with energization. The case portion that houses the motor portion 101 is formed in a rectangular tube shape by the bracket 102 and the bearing housing 104 assembled with the front and rear of the stator 107 interposed therebetween, and the opening end is closed by the flange 106. The bearing housing 104 includes a first bearing housing 104A and a second bearing housing 104B.

  The hollow rotating shaft 103 has a small diameter portion 103a and a large diameter portion 103b, and the left small diameter portion in FIG. 13 is supported by a ball bearing 108 as a normal bearing supported by the bracket 102, and the right large diameter portion 103b. The diameter portion is supported by a thrust radial bearing 109 supported by the bearing housing 104. The inner side of the thrust radial bearing 109 is locked to the rotary shaft 103 by a lock nut member 111 that is screwed onto the outer periphery of the hollow rotary shaft 103.

  The output screw shaft 113 passes coaxially through the hollow portion of the hollow rotary shaft 103 and is screwed into a screw nut 115 positioned in the right side end portion of the hollow rotary shaft 103. The screw nut 115 has a flange portion 115 a that protrudes radially outward from the right-side open end of the hollow rotary shaft 103, and the flange portion 115 a is fixed to the lock nut member 111 via a screw 117.

According to this linear actuator, since the screw nut 115 rotates integrally with the hollow rotary shaft 103, the output screw shaft 113 screwed into the screw nut 115 linearly moves in the left-right direction in the figure. That is, the rotary motion of the hollow rotary shaft 103 is converted into the linear motion of the output screw shaft 113. Note that the output screw shaft 113 is prevented from rotating about its axis by an appropriate detent means.
JP 2002-372118 A

  In such a conventional linear actuator, the body is composed of the four components of the stator 107, the bracket 102, the bearing housing 104A, and the bearing housing 104B. Can be done. For this reason, it is difficult to have an additional function using the body. As an example of the additional function, as shown in FIG. 14, a guide holder 120 is provided in the bearing housing 104 </ b> B, and a moving element 122 that slides along the guide 121 mounted on the guide holder 120 is connected to the output screw shaft 113. It may be used with reciprocating operation. In such a case, since the guide holder 120 is attached to the bearing housing 104B by being screwed or welded to the bearing housing 104B, the rigidity becomes insufficient and the operation of the moving element 122 becomes unstable. Also, when the linear actuator is attached to an attachment part, the attachment rigidity may not be maintained unless all four parts of the stator 107, the bracket 102, the bearing housing 104A, and the bearing housing 104B are fixed to the attachment part. Assembling accuracy or work accuracy was required. Furthermore, accuracy is required for assembling the stator 107, the bracket 102, the bearing housing 104A, and the bearing housing 104B, and the dustproof and waterproof accuracy is insufficient.

  The present invention solves the above-mentioned problem, forms a body in a case, and has a motor part having a hollow rotating shaft in a single case together with a stator of the motor and a bearing that rotatably supports the hollow rotating shaft. It is an object of the present invention to provide a linear actuator and a linear actuator device that are built in and formed into a sealed structure, and that can improve dust resistance and waterproof performance, and can improve rigidity and assembly accuracy.

In order to solve the above problems, the present invention is provided with a motor portion having a hollow rotary shaft, an output screw shaft inserted through the axis of the hollow rotary shaft, and the hollow rotary shaft. A screw nut that is screwed to the output screw shaft, and converts the rotary motion of the hollow rotary shaft into linear motion of the output screw shaft through the screw nut, and the hollow rotary shaft is converted into a small-diameter portion. A linear actuator having a stepped structure having a large-diameter portion, a rotor of the motor portion attached to the small-diameter portion, and a screw nut disposed in the large-diameter portion; and the stator of the motor and the hollow A bearing that rotatably supports the rotating shaft is housed in the same case together with the motor portion having the hollow rotating shaft.
Further, the present invention provides a guide portion on the outer surface of the case along the direction of linear motion of the output screw shaft, a moving element that slides along the guide portion, and the moving element for the output. It is connected to the screw shaft.
Furthermore, the present invention provides a guide hole in the case along the direction of linear motion of the output screw shaft, a guide shaft inserted into the guide hole, and the guide shaft as the output shaft. It is connected to the output end of the screw shaft.
Still further, the present invention provides a linear actuator according to claim 1 disposed in a frame that slidably supports, a table is provided in a case of the linear actuator, and an output screw of the linear actuator is provided in the frame. The shaft is connected.

  Since the stator of the motor and the bearing that rotatably supports the hollow rotary shaft are incorporated in the same case together with the motor portion having the hollow rotary shaft, the rigidity of the body is improved and the mounting part is improved. The mounting surface can be made freely. In addition, since the body is made into a case and a motor part having a hollow rotating shaft is built in the same case together with a stator of the motor and a bearing that rotatably supports the hollow rotating shaft, the body is sealed. It is possible to improve the dustproof and waterproof performance. Since the body is made into the same case, it is not partially fixed compared to an actuator with a conventional guide holder, so it is possible to improve rigidity, reduce the number of parts, and reduce part accuracy it can. Further, by changing the case shape without changing the motor structure, the degree of freedom of the additional function is widened and it can be used as an actuator having a different purpose and application.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to the embodiments shown in the drawings.
1 and 2, reference numeral 10 denotes a linear actuator. The linear actuator 10 has a motor unit 12 built in an integral rectangular tube case 11 constituting a body.
The motor unit 12 includes a hollow rotary shaft 13, a rotor 14 attached to the outer peripheral surface of the rotary shaft 13, and a stator 15 provided around the rotor 14. The stator 15 is provided on the inner peripheral surface of the case 11 and is connected to a driving device (not shown). The stator 15 is energized by the operation of the driving device and generates a rotating magnetic field.

  The hollow rotating shaft 13 includes a small-diameter portion 13a supported by a ball bearing 16 as a normal bearing, and a large-diameter portion 13b supported by a thrust radial bearing 17 as a bearing that receives both thrust load and radial load. It has a stepped structure. The hollow rotary shaft 13 has the rotor 14 attached to the outer peripheral surface of the small diameter portion 13a and a screw nut 18 to be described later disposed in the large diameter portion 13b. The inner side of the bearing 17 is fixed to the large-diameter portion 13b by a lock nut 19 that is screwed onto the outer peripheral surface of the end portion of the large-diameter portion 13b. Since the motor unit 12 has the above-described configuration, the hollow rotary shaft 13 rotates together with the rotor 14 as a stator winding (not shown) is energized.

An output screw shaft 20 is inserted through the hollow portion of the hollow rotary shaft 13 on the axis, and the large diameter portion 13b of the rotary shaft 13 is screwed into the output screw shaft 20. A screw nut 18 is arranged. The screw nut 18 has a flange portion 18 a that protrudes radially outward from the opening end of the rotary shaft 13 on the large diameter portion 13 b side, and the flange portion 18 a is fixed to the lock nut 19 via a bolt 21. Therefore, the screw nut 18 can rotate together with the hollow rotating shaft 13.
The output screw shaft 20 is prevented from rotating by being screwed to the screw nut 18 and linearly moves in the left-right direction as the screw nut 15 rotates. That is, according to this actuator, the rotary motion of the hollow rotary shaft 13 is converted into the linear motion of the output screw shaft 20.

  The case 11 is closed at both end openings by end plates 22 and 23, and the output end 20 a of the output screw shaft 20 is drawn from an opening hole 22 a provided in the end plate 22. A bellows or bellows-like cover member 24 having one end attached to the end plate 22 and the other end fixed to the output end 20a is attached to the output end portion 20a of the output screw shaft 20, and the inside of the case 11 is attached. It is formed in a sealed structure.

  A bracket 25 is provided in the case 11 on the end plate 23 side to support the bearing 16. The bracket 25 divides the inside of the case 11 into a motor unit 12 and a rotation detection unit 26, and the rotation detection unit 26 detects a rotation from the tip of the small diameter portion 13 a of the hollow rotation shaft 13. For example, an encoder, a resolver, or the like is attached.

The operation of the linear actuator 10 of the above embodiment will be described.
When the hollow rotating shaft 13 is rotated by the operation of the motor unit 12, the screw nut 18 is also rotated with the rotation of the hollow rotating shaft 13. As the screw nut 18 rotates, the output screw shaft 20 starts moving in the axial direction. When the hollow rotary shaft 13 is rotated in the reverse direction, the output screw shaft 20 starts moving in the reverse direction. In this way, the output screw shaft 20 starts to reciprocate by switching the rotation direction of the hollow rotary shaft 13 while detecting the rotational speed and the like by the rotation detector 26.
Therefore, since the linear actuator 10 incorporates the motor portion 12 and the like in the integral case 11, the rigidity can be improved. In addition, since the case 11 can be attached in close contact with the attachment portion when assembled to a device or the like, the assembly can be easily and firmly attached. Since the gap between the opening hole 22a of the end plate 22 and the output end portion 20a of the output screw shaft 20 is closed by the cover member 24, dustproof and waterproof performance can be improved.

  Next, FIGS. 3 to 5 show another embodiment of the present invention. The same parts as those in FIGS. 1 and 2 are denoted by the same reference numerals, and the description of the same parts is omitted. In this case, the case 31 of the linear actuator 30 has a guide portion 31a formed on the outer surface thereof in parallel with the hollow rotary shaft 13, and a mover 32 that is slidably engaged with the guide portion 31a. . The mover 32 is a quadrangle of the case 31 and is provided with a connecting portion 32a bent at a right angle to the tip. The output end 20a of the output screw shaft 20 is fixed to the connecting portion 32a by nuts 33a and 33b. Yes. In the linear actuator 30, a plurality of mounting holes 32b and 32c are provided in the plate surface of the moving element 32 and the connecting portion 32a, and are connected to the operating portion via the mounting holes 32b and 32c. As shown in FIG. 4, the linear actuator 30 has guide rails 33 formed on both sides of the case 31 in addition to the guide portion 31 a, and another moving element can be attached using these guide rails 33. The body can also be attached. A plurality of mounting holes 34 and 35 are formed in the side surface of the case 31 or the end plate 22.

  In this linear actuator 30, the case 31 is assembled to a device (not shown), and is connected to the operation unit via the mounting holes 32b and 32c. Thus, as in the above embodiment, when the hollow rotary shaft 13 is rotated by the operation of the motor unit 12 of the linear actuator 30, the screw nut 18 is also rotated with the rotation of the hollow rotary shaft 13. As the screw nut 18 rotates, the output screw shaft 20 starts moving in the axial direction. When the hollow rotary shaft 13 is rotated in the reverse direction, the output screw shaft 20 starts moving in the reverse direction. In this way, the output screw shaft 20 starts to reciprocate by switching the rotation direction of the hollow rotary shaft 13 while detecting the rotation speed and the like by the rotation detector 26. And the connection part 32a connected with the output end part 20a of the screw shaft 20 for output moves, and the moving element 32 is reciprocated. In this way, the operation unit assembled to the movable element 32 can be reciprocated.

  6 and 7 show another embodiment of the present invention. Like the above embodiment, the same parts as those in FIGS. 1 and 2 are denoted by the same reference numerals, and the description of the same parts is omitted. . The linear actuator 40 is suitable for vertical installation or horizontal installation.

  In the case 41 of the linear actuator 40, two through holes 42 are formed on both sides of the hollow rotary shaft 13 in parallel with the hollow rotary shaft 13. The through holes 42 are slidably inserted into the through holes 42. A guide shaft 43 is provided. A connecting tool 44 connected to the output end 20 a of the output screw shaft 20 is connected to the tips of these guide shafts 43 via screws 45. A bushing 46 is built in the inner surface of the through hole 42 to hold the guide shaft 43 movably. The case 41 is provided with a mounting hole 41a to the device, and can be fixed to a vertical wall or a flat surface of the device through the mounting hole 41a.

  In the linear actuator 40, when the hollow rotary shaft 13 is rotated by the operation of the motor unit 12, the screw nut 18 is rotated along with the rotation of the hollow rotary shaft 13. As the screw nut 18 rotates, the output screw shaft 20 starts moving in the axial direction. When the hollow rotary shaft 13 is rotated in the reverse direction, the output screw shaft 20 starts moving in the reverse direction. In this way, the output screw shaft 20 starts to reciprocate by switching the rotation direction of the hollow rotary shaft 13 while detecting the rotation speed and the like by the rotation detector 26. The connecting tool 44 connected to the output end 20 a of the output screw shaft 20 is reciprocated while being guided by the guide shaft 43. The operation unit is operated by the reciprocating motion of the connector 44. A load generated at the operation portion of the linear actuator 40 can be received by the bush 46. The linear actuator 40 can be mainly used for a lifter or the like. A mounting hole 47 for mounting to a device (not shown) is formed on the wall surface of the case 41, and when a separate moving element is attached instead of the guiding shaft 43, or another moving element other than the guiding shaft 43 is provided. A pair of guide grooves 48 used when attaching is formed. The 48 grooves can also be attached to the main body.

8 to 10 show still another embodiment of the present invention. Like the above embodiment, the same parts as those in FIGS. 1 and 2 are denoted by the same reference numerals, and the description of the same parts is omitted. To do.
A linear guide block 52 is mounted on both sides of the case 51 of the linear actuator 50. The linear guide block 52 is formed along the longitudinal direction on both inner side surfaces 53a of a linear guide / frame 53 formed in a box shape. The guide groove 54 is supported via a ball screw 55. On the upper surface of the case 51, an opening 51a is formed at the middle position in the width direction along the longitudinal direction of the case 51, and the table 56 is integrally attached to the upper surface of the case 51 through the opening 51a. .
The linear guide and frame 53 includes a U-shaped lower frame 57 having an upper opening, an upper cover 58 that blocks the opening of the frame 57, and an end block that blocks the front and rear opening ends of the frame 57. 59, 60. The opening 58a is formed in the cover 58, and the table 56 is reciprocated together with the linear actuator 50 through the opening 51a.

  The operation of the linear actuator 50 will be described. When the hollow rotary shaft 13 is rotated by the operation of the motor unit 12, the screw nut 18 is rotated with the rotation of the hollow rotary shaft 13. As the screw nut 18 rotates, the output screw shaft 20 starts moving in the axial direction. When the hollow rotary shaft 13 is rotated in the reverse direction, the output screw shaft 20 starts moving in the reverse direction. In this way, the output screw shaft 20 starts to reciprocate by switching the rotation direction of the hollow rotary shaft 13 while detecting the rotation speed and the like by the rotation detector 26. Since the output end 20 a of the output screw shaft 20 is connected to the end block 59, the linear guide block 52 moves along the guide groove 54 in the linear actuator 50 by the reciprocation of the output end 20 a. Thus, the linear actuator 50 moves relative to the linear guide / frame 53, and the table 56 is reciprocated together with the case 51. Then, the operation unit assembled to the table 56 is operated along with the movement of the linear actuator 50.

11 and 12 show how the linear actuator 30 shown in FIGS. 3 to 5 is attached to a device.
In the embodiment shown in FIG. 11, the end plate 22 of the case 31 is attached to the mounting portion 70 of the equipment via the screw 71, and the end plate of the linear actuator 30 is passed through the screw 71 to the screw hole 70a of the mounting portion 70 of the equipment. 22 is fixed. The output screw shaft 20 of the linear actuator 30 projects the output end 20a from the assembly hole 70b formed in the device mounting portion 70 to the opposite side of the device mounting portion 70. The connecting portion 32a of the mover 32 is fixed to 20a.
Thus, the linear actuator 30 can be attached to the attachment portion 70 of the device via the end plate 22.

  In the embodiment shown in FIG. 12, the side surface of the case 31 is attached to a device mounting portion 80 via a screw 81, and the linear actuator 30 is arranged on the device mounting portion 80 and fixed via a screw 81. It is.

    According to each of the above embodiments, the stator 15 of the motor and the bearings 16 and 17 that rotatably support the hollow rotary shaft 13 together with the motor unit 12 having the hollow rotary shaft 13 are in the same case. Since it is built in 11, 31, 41, 51, the rigidity of the body can be improved, and the mounting surface to mounting parts such as equipment can be made free. Further, the body is formed into a case, and the motor unit 12 having the hollow rotary shaft 13 is supported in the same case 11, 31, 41, 51, and the motor stator 15 and the hollow rotary shaft 13 are rotatably supported. Since the bearings 16 and 17 are built in, the body can be formed in a sealed structure to improve the dustproof and waterproof performance. Since the case is made into the same case 11, 31, 41, 51, it is not partially fixed compared to an actuator provided with a conventional guide holder, so that rigidity is improved, the number of parts is reduced, and parts The accuracy can be reduced. Further, by changing the case shape without changing the motor structure, the degree of freedom of the additional function is widened and it can be used as an actuator having a different purpose and application.

  The present invention is not limited to the above-described embodiment. For example, the shapes of the actuator cases 11, 31, 41, 51 are not limited to the shapes used in the above-described embodiments, but may have various shapes. Can be applied to. Moreover, the attachment to an apparatus is not restricted to the said embodiment, A various attachment structure is employable. Needless to say, the present invention can be implemented with appropriate modifications within a range not changing the gist of the present invention.

It is a perspective view which shows the linear actuator by embodiment of this invention. It is a longitudinal cross-sectional view of FIG. It is a perspective view which shows the linear actuator by other embodiment of this invention. It is a perspective view from the bottom face side of the linear actuator of FIG. It is a longitudinal cross-sectional view of FIG. It is a perspective view which shows the linear actuator by other embodiment of this invention. It is a longitudinal cross-sectional view of FIG. It is a perspective view which shows the linear actuator by other embodiment of this invention. It is a longitudinal cross-sectional view of FIG. FIG. 10 is a sectional view taken along line AA in FIG. 9. It is a perspective view which shows the attachment aspect of the linear actuator of this invention. It is a perspective view which shows the attachment aspect of the linear actuator of this invention. It is a perspective view which shows the conventional linear actuator. It is a longitudinal cross-sectional view which shows the conventional linear actuator.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Linear actuator 11 Case 12 Motor part 13 Hollow rotary shaft 13a Small diameter part 13b Large diameter part 14 Rotor 15 Stator 16 Bearing 17 Thrustal bearing 18 Screw nut 19 Lock nut 20 Output screw shaft 22, 23 End plate 24 Cover member 25 Bracket 26 Rotation detector

Claims (4)

  A motor unit having a hollow rotary shaft; an output screw shaft inserted through an axis of the hollow rotary shaft; and a screw nut disposed in the hollow rotary shaft and screwed into the output screw shaft. The hollow rotary shaft is converted into a linear motion of the output screw shaft through the screw nut, and the hollow rotary shaft is formed in a stepped structure having a small diameter portion and a large diameter portion. In the linear actuator in which the rotor of the motor portion is attached to the small diameter portion and the screw nut is disposed in the large diameter portion, a bearing that rotatably supports the stator of the motor and the hollow rotary shaft is provided. A linear actuator characterized in that it is housed in the same case together with the motor part having the hollow rotating shaft.   A guide portion is provided on the outer surface of the case along the direction of linear movement of the output screw shaft, a mover that slides along the guide portion is provided, and the mover is connected to the output screw shaft. The linear actuator according to claim 1.   A guide hole is provided in the case along the direction of linear movement of the output screw shaft, a guide shaft inserted into the guide hole is provided, and the guide shaft is connected to an output end of the output screw shaft. The linear actuator according to claim 1, wherein the linear actuator is connected to the linear actuator.   The linear actuator according to claim 1 is arranged in a frame that slidably supports, a table is provided in the case of the linear actuator, and an output screw shaft of the linear actuator is connected to the frame. A linear actuator device.

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