JP2013110913A - Linear motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a linear motor which allows a structure that a movable part is not exposed, and allows setting of a short entire length by storing a guide means, such as a spline mechanism, in a sealed structure.SOLUTION: A linear motor includes a magnet rod and a housing that encases a coil loosedly fitted into the magnet rod. A guide means is attached to at least one shaft end part of the magnet rod. An end part of the housing that corresponds to the shaft end part includes a guide shaft protruding from the end part toward the shaft end part. The guide means is supported reciprocally movable along the guide shaft.

Description

  The present invention relates to a linear motor, and more specifically to a linear motor in which guide means for guiding a magnet rod is arranged at the shaft end of the magnet rod.

  2. Description of the Related Art Conventionally, linear motors are known in which a stator and a mover of a motor are linearly arranged to convert electric energy into thrust for linear motion. This linear motor is, for example, a housing that combines a magnet rod formed by laminating a plurality of permanent magnets and pole shoes on a stainless steel pipe or the like, and a cylindrical coil that is loosely fitted to the magnet rod. And.

  In such a linear motor, a magnetic field is generated by passing an electric current through the coil, and a thrust that linearly moves the magnet rod is generated by the interaction between the magnetic field of the coil and the magnetic field of the permanent magnet.

  Further, in order to prevent the rotation of the magnet rod, a spline mechanism as a guide means is formed by a spline groove formed in the magnet rod along the axial direction and a spline nut attached to the housing.

JP 2008-253117 A

  However, according to the conventional linear motor, since the magnet rod is guided by the spline nut attached to the end portion of the housing, the magnet rod moves out of the housing as the magnet rod moves. According to such a configuration, the magnet rod is exposed from the housing, and there has been a problem that it is necessary to take care in use, such as securing a space with the surroundings to prevent mechanical interference of the magnet rod. .

  Further, since the spline nut is attached to the end portion of the housing in the axial direction, there is a problem that it is difficult to design the length of the linear motor in the axial direction short.

  The present invention has been made in order to solve the above-described problems, and by placing guide means such as a spline mechanism in a hermetically sealed structure, a structure in which the movable part is not exposed can be obtained, and the overall length is designed to be short. An object of the present invention is to provide a linear motor that can be used.

  The linear motor according to the present invention includes a magnet rod and a housing containing a coil loosely fitted to the magnet rod, wherein the magnet rod has a guide means attached to at least one shaft end. An end portion of the housing corresponding to the at least one shaft end portion is provided with a guide shaft that protrudes from the end portion toward the at least one shaft end portion, and the guide means extends along the guide shaft. And is supported so as to be able to reciprocate.

  According to the present invention, since the guide means is attached to the shaft end portion of the magnet rod, and the guide shaft protruding toward the magnet rod is formed at the end portion of the housing, the guide means is accommodated in the housing. The total length of the linear motor can be designed shorter than before.

The partial cross section perspective view which shows the linear motor which concerns on embodiment of this invention. The partial cross section perspective view for demonstrating the structure of a guide means. Sectional drawing for demonstrating operation | movement of the linear motor which concerns on embodiment of this invention. Sectional drawing for demonstrating operation | movement of the linear motor which concerns on embodiment of this invention.

  DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments of a linear motor according to the present invention will be described with reference to the drawings. The following embodiments do not limit the invention according to each claim, and all combinations of features described in the embodiments are not necessarily essential to the solution means of the invention. .

  FIG. 1 is a partially sectional perspective view showing a linear motor according to an embodiment of the present invention, FIG. 2 is a partially sectional perspective view for explaining the structure of a guiding means, and FIGS. It is sectional drawing for demonstrating operation | movement of the linear motor which concerns on embodiment of this invention.

  As shown in FIG. 1, the linear motor 1 according to this embodiment includes a magnet rod 10 and a housing 20 that includes a coil 21 that is loosely fitted to the magnet rod 10.

  The magnet rod 10 has a magnet in which an N pole 11 and an S pole 12 are arranged mutually, and a pole shoe 13 is interposed between the N pole 11 and the S pole 12 and stacked. The magnets 11 and 12 and the pole shoe 13 are inserted and laminated on a nonmagnetic stainless steel pipe 14. Furthermore, a spline nut 30 as a guide means is attached to one end of the stainless steel pipe 14 in the axial direction via an attachment means 32.

  The attachment means 32 is formed in a hollow shape so that a guide shaft 31 to be described later can be inserted, and has a diameter-expanded portion 32a for assembling the spline nut 30 and a contraction formed to have substantially the same diameter as the outer diameter of the magnet rod 10. It is comprised from the diameter part 32b. The attachment means 32 is attached and fixed to the shaft end of the magnet rod 10 by caulking or the like.

  The housing 20 includes a drive unit 24 that includes the coil 21 and a cover unit 23 that houses the magnet rod 10. The coil 21 included in the drive unit 24 constitutes a set of three-phase coils composed of U, V, and W phases into which the magnet rod 10 is loosely fitted. As described above, when a three-phase current having a phase difference of 120 ° is applied to the three-phase coil 21, a moving magnetic field that moves in the axial direction of the coil 21 is generated. Thus, the linear motion of the magnet rod 10 synchronized with the speed of the moving magnetic field is realized. The coil 21 is supplied with power through the power supply unit 25.

  The cover portion 23 is formed in a hollow shape extending from the drive portion 24 along the axial direction of the magnet rod 10, and a guide shaft 31 is attached to the end portion thereof via the side lid 22. . The guide shaft 31 protrudes from the side cover 22 toward the inside of the cover portion 23, and is combined with a spline nut 30 attached to the shaft end of the magnet rod 10.

  Next, the configuration of the spline nut 30 and the guide shaft 31 will be described with reference to FIG. The guide shaft 31 is a shaft member in which a plurality of rolling element rolling grooves 31a are formed along the axial direction, and the spline nut 30 is formed in a substantially cylindrical shape having a hollow hole through which the guide shaft 31 passes. In addition, it is assembled to the guide shaft 31 via a large number of rolling elements 40.

  The guide shaft 31 is formed in a substantially circular shape in a cross section perpendicular to the axial direction, and, for example, six rolling element rolling grooves 31a along the longitudinal direction are formed on the outer peripheral surface thereof. These rolling element rolling grooves 31 a are formed as a pair of two adjacent rolling element rolling grooves 31 a, and a total of three sets are formed, and three sets of rolling element rolling grooves 31 a are outer peripheral surfaces of the guide shaft 31. Is divided into approximately three equal parts.

  The spline nut 30 includes an outer cylinder 33 having a hollow hole and formed in a cylindrical shape, and a pair of end plates 34 fitted to both ends of the hollow hole of the outer cylinder 33. On the inner periphery of the hollow hole of the outer cylinder 33, there are a load rolling element rolling groove 35 facing the rolling element rolling groove 31 a formed in the guide shaft 31, and an outer cylinder substantially parallel to the load rolling element rolling groove 35. A rolling element return path 36 penetrating 33 in the axial direction is formed.

  Further, both ends of the rolling element rolling path and the rolling element return path 36 constituted by the load rolling element rolling groove 35 and the rolling element rolling groove 31 a are connected to the surface of the end plate 34 facing the outer cylinder 33. Thus, the direction change path 34a is formed.

  The rolling elements 40 are arranged in an infinite circulation path that circulates through the rolling element rolling path, the direction changing path 34a, and the rolling element return path 36, and a spacer 41 is interposed between the adjacent rolling elements 40. Each spacer 41 is formed in a substantially disk shape smaller than the diameter of the rolling element 40, and is formed in a concave shape on the surface facing the rolling element 40 so as to correspond to the shape of the rolling element 40.

  As described above, since the spacers 41 are interposed between the plurality of rolling elements 40, the rolling elements 40 are prevented from coming into contact with each other when rolling in the endless circulation path, and generation of abnormal noise and rolling. Wear of the moving body 40 can be prevented.

  As described above, since the spline nut 30 is assembled to the guide shaft 31 via the plurality of rolling elements 40, the spline nut 30 is movable along the guide shaft 31 and is relative to the guide shaft 31. To prevent it from rotating.

  Next, the operation of the linear motor 1 according to this embodiment will be described with reference to FIGS. FIG. 3 shows a state where the magnet rod 10 has moved to one end and the linear motor 1 has extended as a whole, and FIG. 4 shows a state in which the magnet rod 10 has moved to the other end and the linear motor 1 has shrunk as a whole. Is shown.

  As shown in FIG. 3, when a magnetic field is generated by passing a current through the coil 21, the magnet rod 10 linearly moves in one direction due to the interaction between the magnetic field of the coil 21 and the magnetic field of the magnet rod 10. The spline nut 30 attached to is moved to one end of the guide shaft 31. Thus, in the state where the linear motor 1 is extended, the spline nut 30 attached to the end of the magnet rod 10 is the end of the guide shaft 31 (the end opposite to the end fixed by the side cover 22). The tip of the guide shaft 31 and the magnet rod 10 have a space S in the attachment means 32.

  Next, when a reverse-phase current is passed through the coil 21, the magnet rod 10 starts moving in the reverse direction. Then, the spline nut 30 moves along the guide shaft 31 to the root of the guide shaft (the end fixed by the side lid 22). In this state, as shown in FIG. 4, the guide shaft 31 is immersed in the space S formed in the reduced diameter portion 32 b of the attachment means 32, so that the magnet rod 10 and the guide shaft 31 do not interfere with each other. .

  Even when the linear motor 1 is contracted, the magnet rod 10 is not exposed because the magnet rod 10 is accommodated in the cover portion 23.

  Thus, in the linear motor 1 according to the present embodiment, the magnet rod 10 is not exposed because the end of the magnet rod 10 is accommodated in the cover part 23 as the magnet rod 10 moves. In order to prevent mechanical interference of the magnet rod 10, it is not necessary to pay attention to use such as securing a space with the surroundings.

  Moreover, since the linear motor 1 which concerns on this embodiment has attached the spline nut 30 to the magnet rod 10, the color used when attaching a guide shaft to a magnet rod becomes unnecessary, Therefore Only the length of a color The length of the magnet rod can be designed to be short, and a hollow mounting means with a space formed therein is used, so that the guide shaft 31 can be moved in and out of the space. Can be set short.

  In the linear motor 1 according to the present embodiment, the attachment means 32 is formed in a hollow shape, and the diameter-reduced portion 32a to which the spline nut 30 is attached and the space S in which the guide shaft 31 can go in and out is formed. Since the portion 32b is provided, the space S in which the guide shaft 31 can enter and exit can be configured with a simple configuration.

  Moreover, since the linear motor 1 which concerns on this embodiment can employ | adopt a spline shaft as the spline nut 30 and the guide shaft 31 as a guide means, it becomes possible to comprise a guide means with an easy structure, Since various types of spline devices can be employed, the degree of freedom in design is increased.

  In the linear motor 1 according to the present embodiment, the guide shaft 31 is included in the hollow cover portion 23 formed at one end of the housing 20, and the side cover 22 attached to the end portion of the cover portion 23. Since it is attached, the guide shaft 31 can be reliably disposed in the cover portion 23 with an easy configuration.

  Moreover, although the magnet rod 10 applied to the linear motor 1 according to the present embodiment has been described with respect to the case where the magnets 11 and 12 and the pole shoe 13 are stacked in the stainless steel pipe 14, the magnets 11 and 12 and the pole shoe 13 are described. As long as it can be laminated, the stainless steel pipe 14 may be omitted. Further, the magnet rod 10 may be formed by stacking the magnets 11 and 12 without using the pole shoe 13.

  Moreover, although the spline nut 30 applied to the linear motor 1 which concerns on this embodiment demonstrated the case where the spacer 41 was interposed between the some rolling elements 40, the number of the rolling elements 40 was increased and load capacity was increased. In order to ensure, the spacer 41 may be omitted.

  Moreover, although the guide shaft 31 applied to the linear motor 1 according to the present embodiment has been described for the case where six rolling element rolling grooves 31a are formed, the number of rolling element rolling grooves is not limited thereto, and is necessary. It is possible to increase or decrease appropriately according to. It is apparent from the scope of the claims that the embodiments added with such changes or improvements can be included in the technical scope of the present invention.

  1 linear motor, 10 magnet rod, 20 housing, 21 coil, 22 side lid, 30 spline nut (guide means), 31 guide shaft, 32 mounting means, 32a expanded diameter portion, 32b reduced diameter portion, S space.

Claims (6)

A magnet rod,
In a linear motor comprising a housing containing a coil loosely fitted to the magnet rod,
The magnet rod has a guide means attached to at least one shaft end,
An end portion corresponding to the at least one shaft end portion of the housing includes a guide shaft protruding from the end portion toward the at least one shaft end portion,
The linear motor is characterized in that the guide means is supported so as to reciprocate along the guide shaft. The linear motor according to claim 1,
The linear motor is characterized in that the guide means is attached to the at least one shaft end portion via attachment means. The linear motor according to claim 2,
The linear motor is characterized in that the attachment means is formed in a hollow shape so that the guide shaft can be inserted therethrough. The linear motor according to claim 3,
The linear motor is characterized in that the attachment means includes a diameter-expanded portion for assembling the guide means and a diameter-reduced portion for inserting the guide shaft. The linear motor according to any one of claims 1 to 4,
The guide shaft is a spline shaft in which a guide groove is formed in the axial direction,
The linear motor according to claim 1, wherein the guide means is a spline nut assembled to the spline shaft so as to be reciprocally movable. The linear motor according to any one of claims 1 to 5,
The housing is formed in a hollow shape capable of containing the magnet rod and the guide means,
The linear motor is characterized in that the guide shaft is attached to a side lid attached to the end of the housing.

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