JP5516899B2 - Linear motor and method for manufacturing linear motor - Google Patents

Description

  The present invention relates to a rod-type linear motor that reciprocates a mover relative to a stator.

  Conventionally, it has a mover in which a plurality of magnetic poles are arranged at a predetermined pitch in the axial direction and a cylindrical stator in which a plurality of coils through which the mover is inserted are arranged, and the mover is attached to the stator. A rod-type linear motor that reciprocates is proposed (see, for example, Patent Document 1).

  This linear motor has a frame provided with a stator on the inner side, bearing holding members (flange portions) disposed on both sides in the axial direction of the frame, and a linear bush held by the bearing holding member. Yes. The linear bush supports a rod provided with a mover so as to be movable in the axial direction.

JP 2001-352747 A

  In general, in a linear motor, it is necessary to secure a minute gap between the mover and the stator. Moreover, when the axial center shift | offset | difference or inclination arises between the linear bushes of the axial direction both sides, when a rod slides, resistance may increase or a catch may generate | occur | produce. For this reason, it is indispensable to ensure concentricity between the axis of the linear bush (that is, the axis of the mover) and the axis of the stator.

  In the above-described conventional linear motor, a frame provided with a stator and a bearing holding member that holds a bearing are configured as separate members. In the linear motor having such a configuration, in order to ensure the above concentric accuracy, the bearing holding member and the frame are positioned by using, for example, an inlay coupling or a positioning pin, thereby aligning the linear bush and the stator. It is common to do it.

  However, when the bearing holding member and the frame are positioned by inlay connection, high processing accuracy is required for each member. Moreover, when positioning a bearing holding member and a flame | frame using a positioning pin, work, such as insertion and fixing of a pin, is needed in an assembly | attachment operation | work, and will require an effort.

The present invention has been made in view of such problems, and a linear motor and a linear motor that can easily ensure the concentric accuracy of the mover and the stator while eliminating the need for highly accurate processing of members. An object is to provide a method for manufacturing a motor .

In order to solve the above problems, the present invention is configured as follows.
The invention according to claim 1 includes a field and an armature, wherein either one of the field or the armature is a mover and the other is a stator, and the mover can be reciprocated relative to the stator. A rod provided with the field; a cylindrical yoke through which the rod is inserted; and the armature is provided on an inner peripheral surface; the rod disposed on both axial sides of the yoke; A pair of bearings that support the cylindrical yoke main body portion provided with the armature on the inner peripheral surface, and the yoke main body portion has a different diameter, and the yoke includes a pair of bearings. of a tubular bearing holding portion for holding at least one, and possess integrally, and the yoke body portion and the bearing holder is characterized in that formed in one member.

  According to a second aspect of the present invention, in the linear motor according to the first aspect, the yoke integrally includes a first bearing holding portion that holds a load-side bearing of the pair of bearings. .

Further, the invention of claim 3, in the linear motor according to claim 2 wherein, prior Symbol first bearing holder is characterized in that has a smaller diameter than the yoke main body.

  According to a fourth aspect of the present invention, in the linear motor according to the second or third aspect, the yoke integrally includes a second bearing holding portion that holds a bearing on the opposite side of the pair of bearings. It is a feature.

The invention of claim 5 is the linear motor according to claim 4, wherein, prior Symbol second bearing holder is characterized in that has a larger diameter than the yoke main body.

  According to a sixth aspect of the present invention, in the linear motor according to the third or fifth aspect, the yoke body includes a convex portion for securing a region for connecting a plurality of coils constituting the armature, and the electric machine. And an opening for inserting a cable connected to the child.

  According to a seventh aspect of the present invention, in the linear motor according to the sixth aspect, the frame is provided on the outer peripheral side of the yoke main body portion, and is disposed at the axial end portion of the frame to house the bearing holding portion. And at least one bearing cover.

  According to an eighth aspect of the present invention, in the linear motor according to the seventh aspect, the frame and the bearing cover are integrally formed.

The invention according to claim 9 is the linear motor according to any one of claims 1 to 8, wherein the bearing is a linear motion bearing that supports the rod so as to be movable in the axial direction. .
The invention of claim 10 is a method of manufacturing a linear motor comprising a rod provided with a field, and a cylindrical yoke through which the rod is inserted and provided with an armature on an inner peripheral surface thereof. A pipe is installed inside a mold in which a predetermined shape is formed in a concave shape, and the diameter of the pipe is partially expanded by setting the fluid flowing inside the pipe to a high pressure, and a large diameter portion and a small diameter portion are provided. Forming the yoke; and fixing a bearing supporting the rod to one of the large diameter portion and the small diameter portion and fixing the armature to the other.

According to the linear motor and the method of manufacturing the linear motor of the present invention, it is possible to easily ensure the concentric accuracy of the mover and the stator while eliminating the need for highly accurate processing of the member.

It is the longitudinal cross-sectional view and the cross-sectional view showing the whole linear motor structure of this embodiment. It is the longitudinal cross-sectional view and the cross-sectional view showing the whole linear motor structure in the comparative example of this embodiment. It is the longitudinal cross-sectional view showing the whole linear motor structure in the modification which integrates a frame and a bearing cover, and a cross-sectional view. It is the longitudinal cross-sectional view and the cross-sectional view showing the whole linear motor structure in the modification in which the yoke has the bearing holding part on both sides of the load side and the anti-load side.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

  Fig.1 (a) is a longitudinal cross-sectional view showing the whole linear motor structure of this embodiment, FIG.1 (b) is the IB-IB cross section in Fig.1 (a) of the linear motor of this embodiment. It is a cross-sectional view showing the whole structure.

  1 (a) and 1 (b), a linear motor 1 includes a field 2 and an armature 3, with the field 2 as a mover, the armature 3 as a stator, and the mover as a stator. It is a rod-type linear motor that can reciprocate. The linear motor 1 includes a rod 4 provided with a field 2, a cylindrical yoke 5 through which the rod 4 is inserted, and a pair of bearings 6 that are disposed on both sides of the yoke 5 in the axial direction and support the rod 4. 7.

  In the central portion of the rod 4 in the axial direction, the field 2 (movable element in the present embodiment; hereinafter also referred to as “movable element 2”) is provided. The field 2 is composed of a plurality of permanent magnets (not shown), and forms a plurality of magnetic poles along the axial direction. The armature 3 is provided on the inner peripheral surface of the yoke 5 so as to face the outer peripheral surface of the mover 2 provided on the rod 4 with a minute gap. This armature 3 (stator in the present embodiment; hereinafter also referred to as “stator 3” as appropriate) is configured by arranging a plurality of coils 8 formed in a cylindrical shape with copper wires or the like in the axial direction.

  The bearings 6 and 7 are linear motion bearings such as linear bushes and ball splines, for example, and support the rod 4 inserted through the yoke 5 so as to be linearly movable in the axial direction. The bearing 6 is disposed on the load side, and the bearing 7 is disposed on the anti-load side.

  The yoke 5 includes a yoke main body 51 provided with the armature 3 on the inner peripheral surface, and a bearing holding portion 52 for holding the bearing 6 disposed on the load side in at least one of the bearings 6 and 7. Are integrated. The bearing holding portion 52 is disposed on the load side of the yoke body 51 and is formed with a smaller diameter than the yoke body 51. The bearing holding portion 52 corresponds to the first bearing holding portion described in the claims. Further, the yoke body 51 is provided with a projection 53 for securing a region S for connecting a plurality of coils 8 constituting the armature 3 and a cable 9 connected to the armature 3. An opening 54 is formed. The convex portion 53 is formed along the axial direction over substantially the entire length of the yoke main body portion 51, and the opening portion 54 is formed at the non-load side end portion of the convex portion 53.

  Specifically, the yoke 5 having the above-described configuration is manufactured as follows. First, a pipe having a diameter of the bearing holding portion 52 is prepared, and a die in which the shapes of the yoke main body 51, the convex portion 53, and the like are formed in a concave shape is disposed around the pipe. Then, a fluid is poured into the inside of the pipe to seal both ends thereof, the fluid is made high pressure, and the diameter of the pipe is partially expanded by the pressure. Thereby, the yoke 5 which integrally has the yoke main-body part 51 and the bearing holding | maintenance part 52 is formed. Such processing is conventionally known as so-called bulge processing. In the yoke 5 formed in this way, the fluid pressure acts evenly in the circumferential direction of the pipe, so that the concentric accuracy between the yoke body 51 and the bearing holder 52 is easily ensured.

  A frame 10 having a quadrangular cross section made of a metal material such as aluminum is provided on the outer peripheral side of the yoke body 51. A bracket 11 that holds the bearing 7 is provided at the axial end of the frame 10 on the side opposite to the load. On the other hand, a bearing cover 12 that houses the bearing holding portion 52 of the yoke 5 is provided at the axial end of the frame 10 on the load side. Unlike the bracket 11 for supporting and fixing the bearing 7, the bearing cover 12 is merely for covering the bearing holding portion 52. For this reason, a gap is provided between the inner peripheral surface of the bearing cover 12 and the outer peripheral surface of the bearing holding portion 52. The frame 10, the bracket 11, and the bearing cover 12 are configured so that the outer diameters are uniform.

  Since the load-side bearing 6 is held by the bearing holding portion 52 of the yoke 5 as described above, the bearing cover 12 is not necessarily provided.

  Here, before describing the effects of the present embodiment described above, a comparative example for describing the effects of the present embodiment will be described with reference to FIG. FIG. 2A is a longitudinal sectional view showing the overall configuration of the linear motor in the comparative example, and FIG. 2B is the overall configuration of the linear motor of the comparative example, taken along the IIB-IIB cross section in FIG. FIG. 2 (a) and 2 (b) are diagrams corresponding to FIGS. 1 (a) and 1 (b). For convenience of comparison, the reference numerals of the respective parts in the comparative example are the same as those in the present embodiment. Used.

  The configuration of the linear motor 1 ′ of the comparative example is different from the configuration of the linear motor 1 of the present embodiment in that the yoke does not have a bearing holding portion. That is, as shown in FIGS. 2A and 2B, in the linear motor 1 ′ in the comparative example, the yoke 5 ′ is configured only by the yoke body 51 and does not have a bearing holding portion. For this reason, a bracket 12 ′ that holds the bearing 6 is provided at the axial end of the frame 10 on the load side, similarly to the anti-load side. The bracket 12 ′ is for supporting and fixing the bearing 6 in the same manner as the bracket 11 on the anti-load side. About another structure, it is the same as that of the linear motor 1 of this embodiment.

  The linear motor 1 ′ of the comparative example has the following problems. That is, in general, in a linear motor, it is necessary to secure a minute gap between the mover and the stator. Further, when the shaft core is displaced or inclined between the bearings on both sides in the axial direction, there is a possibility that the resistance increases or the hook is generated when the rod slides. For this reason, it is essential to ensure concentricity between the shaft axis of the bearing (that is, the axis of the mover) and the axis of the stator.

  At this time, in the linear motor 1 'of the comparative example, a bracket for holding the yoke 5' (or the frame 10) having the stator 3 on the inner peripheral surface and the bearings 6 and 7 on the load side and the anti-load side. 12 'and 11 are comprised by another member. In such a configuration, in order to ensure concentric accuracy of the movable element 2 and the stator 3, the brackets 12 'and 11 for holding the bearings 6 and 7 and the yoke 5' (or the frame 10) provided with the stator 3 are provided. ) Is positioned using, for example, an inlay coupling or a positioning pin, so that the bearings 6 and 7 and the stator 3 are generally centered. However, in this case, high processing accuracy is required for each member such as the brackets 12 'and 11 and the yoke 5' (or the frame 10), and work such as insertion and fixing of pins is required in assembling work. It will be.

  On the other hand, in the linear motor 1 of the present embodiment, the bearing holding portion 52 that holds the load-side bearing 6 and the yoke body portion 51 on which the stator 3 is provided are configured as one member. Such positioning work and assembly work are not required. Also, as described above, the bearing holding portion 52 can be integrally provided on the yoke 5 by so-called bulging that allows a fluid to flow inside the pipe and partially expand the inner diameter by the pressure. In such processing, the concentric accuracy of the yoke body 51 and the bearing holding portion 52 is easily ensured. If the yoke body 51 and the bearing holding part 52 have the same axis, the yoke body 51 and the bearing 6 (that is, the rod 4) have the same axis. As a result, the stator provided in the yoke body 51 3 and the mover 2 provided on the rod 4 have the same axis. Therefore, the concentric accuracy of the mover 2 and the stator 3 can be easily ensured while eliminating the need for highly accurate processing of the member.

  In the present embodiment, the following effects are obtained. In other words, in general, in a linear motor, when a shaft misalignment or inclination occurs in a pair of bearings provided on both sides in the axial direction, there is a possibility that resistance increases or a hook is generated when the rod slides. is there. In particular, since the load-side bearing receives a larger force than the anti-load-side bearing, the influence of the above-described problem is increased. Therefore, in the present embodiment, the yoke 5 integrally includes the bearing holding portion 52 that holds the load-side bearing 6 among the pair of bearings 6 and 7, so that at least the concentric accuracy of the load-side bearing 6 is achieved. And the occurrence of the above problems can be suppressed.

  In the present embodiment, in particular, the bearing holding portion 52 is formed to have a smaller diameter than the yoke main body portion 51 provided with the armature 3. As a result, the bearing 6 that is generally configured with an outer diameter smaller than that of the armature 3 can be reliably held by the bearing holding portion 52.

  In the present embodiment, in particular, the yoke body 51 is inserted through the convex portion 53 for securing the region S for connecting the plurality of coils 8 constituting the armature 3 and the cable 9 connected to the armature 3. And an opening 54 for this purpose. Thereby, the plurality of coils 8 provided on the inner peripheral surface of the yoke main body 51 can function as the armature 3 of the linear motor 1.

  In this embodiment, in particular, the linear motor 1 is arranged at the frame 10 provided on the outer peripheral side of the yoke main body 51 and the axial end of the load side of the frame 10 and accommodates the bearing holding portion 52. And a cover 12. By providing the frame 10 and the bearing cover 12 in this way, the entire yoke 5 can be covered and protected. Further, by forming the frame 10 and the bearing cover 12 to have appropriate thicknesses, the outer diameter of the linear motor 1 can be made uniform even when the diameters of the yoke body 51 and the bearing holding portion 52 are different as in the above embodiment. This also has the effect of improving the handleability.

  The present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit and technical idea of the present invention. Hereinafter, such modifications will be described in order.

(1) When integrating the frame and the bearing cover In the above-described embodiment, the frame 10 and the bearing cover 12 are configured as separate members, but they may be integrated.

  Fig.3 (a) is a longitudinal cross-sectional view showing the whole linear motor structure of this modification, FIG.3 (b) is a linear motor of this modification by the IIIB-IIIB cross section in Fig.3 (a). It is a cross-sectional view showing the whole structure. 3 (a) and 3 (b) correspond to FIGS. 1 (a) and 1 (b) described above, and the same parts are denoted by the same reference numerals and description thereof will be omitted as appropriate.

  As shown in FIGS. 3A and 3B, in the linear motor 1A of the present modification, a frame 100 having a rectangular cross section made of a metal material such as aluminum is provided on the outer peripheral side of the yoke body 51. ing. The frame 100 integrally includes a bearing cover portion 101 that houses the bearing holding portion 52 of the yoke 5 at the axial end portion on the load side. That is, the linear motor 1A of this modification has a configuration in which the frame 10 and the bearing cover 12 in the linear motor 1 shown in FIG. 1 are integrated. Other configurations are the same as those of the linear motor 1 of the above embodiment.

  According to the linear motor 1A of the present modification, the number of parts and the cost can be reduced by integrally configuring the frame 100 and the bearing cover portion 101 as compared with the case where they are configured by separate parts. Further, when separate parts are used, a connecting operation is required. However, by integrating them, these operations are not necessary, so that the number of man-hours required for the assembling operation can be reduced and the assembling operation can be performed efficiently.

(2) When the yoke has bearing holding portions on both the load side and the anti-load side In the above embodiment, the yoke 5 holds only the load-side bearing 6 by the bearing holding portion 52. However, the yoke 5 may also hold the bearing on the anti-load side.

  FIG. 4A is a longitudinal sectional view showing the entire configuration of the linear motor of this modification, and FIG. 4B is a cross-sectional view of the linear motor of this modification according to the IVB-IVB section in FIG. It is a cross-sectional view showing the whole structure. 4 (a) and 4 (b) correspond to FIGS. 1 (a) and 1 (b) described above, and the same parts are denoted by the same reference numerals and description thereof will be omitted as appropriate.

  As shown in FIGS. 4A and 4B, in the linear motor 1B of the present modification, the yoke 5 is integrally formed with a bearing holding portion 55 that holds the bearing 7B on the opposite side of the pair of bearings 6 and 7B. Have. The bearing holding portion 55 is disposed on the side opposite to the load of the yoke main body 51, and has a larger diameter than the yoke main body 51 in order to secure a space for inserting the armature 3 into the yoke main body 51. Has been. Accordingly, the bearing 7B on the anti-load side has a larger diameter than the bearing 6 on the load side. The bearing holding portion 55 corresponds to the second bearing holding portion described in the claims.

  A bearing cover 13 that houses the bearing holding portion 55 of the yoke 5B is provided at the axial end of the frame 10A on the side opposite to the load. The bearing cover 13 is simply for covering the bearing holding portion 55, similarly to the bearing cover 12 on the load side. For this reason, a gap is provided between the inner peripheral surface of the bearing cover 13 and the outer peripheral surface of the bearing holding portion 55. The bearing cover 13 is formed to have a larger diameter than the frame 10 </ b> A according to the diameter of the bearing holding portion 55 housed inside. Further, an enlarged diameter portion 102 having substantially the same diameter as that of the bearing cover 13 is formed at an end portion on the opposite side of the frame 10A. Other configurations are the same as those of the linear motor 1 of the above embodiment.

  In the linear motor 1B of the present modification, the yoke 5B has a bearing holding portion 55 for holding the anti-load side bearing 7B in addition to the bearing holding portion 52 for holding the load side bearing 6. Thereby, since both a pair of bearings 6 and 7B can be hold | maintained by the yoke 5B, the concentric accuracy of the needle | mover 2 and the stator 3 is more than the said embodiment of the structure which hold | maintains only the bearing 6 on the load side. Can be ensured more easily and reliably. In addition, by making the bearing holding portion 55 on the non-load side larger than the diameter of the yoke body 51, a space for inserting the armature 3 into the yoke body 51 can be secured.

(3) Others In the above, the case where the bearings 6 and 7 are linear motion bearings has been described as an example. However, the present invention is not limited to this. For example, when the rod 4 is linearly driven and rotationally driven, the bearing 6 , 7 etc. may be constituted by linear motion rotary bearings.

  In the above description, for example, when the bearing holding portion is provided only on one side in the axial direction of the yoke main body portion, the bearing holding portion is provided on the load side. Moreover, when providing only in one side of an axial direction, you may form a bearing holding part larger diameter than a yoke main-body part. Further, when the bearing holding portions are provided on both sides in the axial direction of the yoke main body as described in the modification (2), the bearing holding portion on one side has a smaller diameter than the yoke main body, and the bearing holding portion on the other side. However, the present invention is not limited to this, and the bearing holding portions on both sides may be formed to have a larger diameter (or the same diameter) than the yoke main body.

  In the above description, the case where the field 2 is a mover and the armature 3 is a stator has been described as an example. However, the present invention is not limited to this, and the field 2 is a stator and the armature 3 is a mover. The present invention may be applied to a linear motor. In this case as well, the same effects as those in the above embodiment are obtained.

In addition to those already described above, the methods according to the above-described embodiments and modifications may be used in appropriate combination.
In addition, although not illustrated one by one, the present invention is implemented with various modifications within a range not departing from the gist thereof.

1, 1A, 1B Linear motor 2 Field (mover)
3 Armature (stator)
4 Rod 5 Yoke 6, 7 Bearing 7B Bearing 8 Coil 9 Cable 10 Frame 12 Bearing cover 13 Bearing cover 51 Yoke body portion 52 Bearing holding portion (first bearing holding portion)
53 Convex part 54 Opening part 55 Bearing holding part (second bearing holding part)
100 frame 101 bearing cover S area

Claims (10)

A linear motor comprising a field and an armature, wherein one of the field and the armature is a mover, the other is a stator, and the mover is reciprocally movable with respect to the stator;
A rod provided with the field;
A cylindrical yoke in which the rod is inserted and the armature is provided on an inner peripheral surface;
A pair of bearings disposed on both sides in the axial direction of the yoke and supporting the rod;
The yoke is
A cylindrical yoke body provided with the armature on the inner peripheral surface;
The different yoke main body and the diameter, and a cylindrical bearing holding portion for holding at least one of said pair of bearings possess integrally,
The linear motor according to claim 1, wherein the yoke body and the bearing holding part are formed of a single member . The yoke is
The linear motor according to claim 1, wherein the linear motor integrally includes a first bearing holding portion that holds a load-side bearing among the pair of bearings. Prior Symbol first bearing holder,
The linear motor according to claim 2, wherein the linear motor is smaller in diameter than the yoke main body. The yoke is
4. The linear motor according to claim 2, wherein the linear motor integrally includes a second bearing holding portion that holds a bearing on the opposite side of the pair of bearings. Prior Symbol second bearing holding portion,
The linear motor according to claim 4, wherein the linear motor is formed to have a larger diameter than the yoke main body. The yoke body is
A convex portion for securing a region for connecting a plurality of coils constituting the armature;
The linear motor according to claim 3, further comprising an opening for inserting a cable connected to the armature. A frame provided on the outer peripheral side of the yoke body,
The linear motor according to claim 6, further comprising at least one bearing cover that is disposed at an axial end portion of the frame and accommodates the bearing holding portion. The linear motor according to claim 7, wherein the frame and the bearing cover are integrally formed. The bearing is
The linear motor according to claim 1, wherein the linear motor is a linear motion bearing that supports the rod so as to be movable in an axial direction. A method of manufacturing a linear motor, comprising: a rod provided with a field; and a cylindrical yoke provided with an armature on an inner peripheral surface through which the rod is inserted,
Installing a pipe inside a mold in which a predetermined shape is formed in a concave shape;
Forming the yoke having a large diameter portion and a small diameter portion by partially expanding the diameter of the pipe by setting the fluid flowing inside the pipe to a high pressure;
Fixing a bearing that supports the rod to one of the large diameter portion and the small diameter portion, and fixing the armature to the other;
A method for manufacturing a linear motor, comprising:

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