JP2011097750A - Linear motor actuator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a downsized linear motor actuator wherein the magnetic flux of the linear motor acting on a rolling element is reduced. <P>SOLUTION: A moving block 2 is attached movably to a track rail 1. The movement block has a rolling body circulation route including a loaded rolling body rolling section facing the rolling body rolling section 10 of the rail track 1. Many rolling bodies are interposed to perform rolling motion between the rolling body rolling section 10 of the rail track 1 and the loaded rolling body rolling section of the moving block 2. The stator 5 of the linear motor is fixed to the track rail 1, and the mover 4 of the linear motor which faces the stator 5 through a clearance is fixed to the moving block 2. The rolling body train and the linear motor interposed between the rolling body rolling section 10 of the rail track 1 and the loaded rolling body rolling section of the moving block 2 are separated in the vertical direction in the state where the track rail 1 is fixed to a horizontal fixing plane. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a linear motor actuator that linearly moves a conveyed product along a track rail.

  Actuators that linearly move conveyed objects along track rails are incorporated in loading systems that load and unload workpieces on machine tools such as lathes, and automatic warehouses that automatically store and retrieve stored items at storage locations. It is. In the case of the loading system, a long track rail extending from one end of the room to the other is stretched, and the work is conveyed along the track rail and passed to the machine tool through the loader. In the case of an automatic warehouse, track rails are stretched horizontally and vertically on the ceiling and walls of the warehouse, and the contents are automatically transported from the entrance to the storage location along the track rails.

  An actuator that conveys a workpiece and a storage object includes a track rail and a table that moves along the track rail and on which the workpiece and the storage object are placed. A cam follower that rolls on the track rail like a wheel is attached to the table. The linear motion of the table is guided by track rails and cam followers. In addition, in order to generate a driving force for moving the table, a rack is laid along the track rail, and a pinion that meshes with the rack is attached to the table. A driving force for moving the table is generated by rotating the pinion using the rotary motor.

  However, this type of loading system or automatic warehouse has a problem that the roller of the cam follower moves on the track rail while swaying, making it impossible to move the conveyed object quietly and with high accuracy. In addition, since the rack and pinion mechanism is used as the drive mechanism, there is a problem that the actuator becomes large and the backlash increases due to wear.

  As a linear motor actuator that solves this problem, positions a conveyed object with high accuracy, and achieves a compact size, Patent Document 1 discloses a linear slide in which a guide portion and a linear motor portion are integrated. In this linear slide, a linear guide is used as a guide portion, and a large number of rolling elements are interposed between the guide rail and the movable member so as to allow rolling motion. Further, in order to integrate the guide portion and the linear motor portion, a permanent magnet of the linear motor is attached to the track rail, and a coil of the linear motor is attached to the movable member.

JP 2000-102237 A

  However, the linear slide described in Patent Document 1 adopts a structure in which the linear motor is sandwiched between a pair of rolling element rows in order to keep the clearance between the permanent magnet and the coil of the linear motor constant. is doing. Since the space of the guide portion is taken up by the linear motor, there is a problem that the guide portion has to be enlarged once to give the guide portion the necessary rigidity. Furthermore, since the magnetic field of the permanent magnet also acts on the rolling elements made of steel, the rolling elements stick together like a magnet, and the rolling elements move poorly, or the rolling elements that roll and move are made of iron powder, etc. There is also a problem that the smooth rolling motion of the rolling element is obstructed.

  Therefore, an object of the present invention is to provide a linear motor actuator capable of reducing the size of the linear motor actuator and reducing the magnetic flux of the linear motor from acting on the rolling elements.

The present invention will be described below.
One aspect of the present invention is a rolling element circuit including a track rail in which rolling element rolling portions are formed along a longitudinal direction, and a loaded rolling element rolling portion facing the rolling element rolling portion of the track rail. And a movable block that is movably assembled to the track rail, and is interposed between the rolling element rolling part of the track rail and the load rolling element rolling part of the movable block so as to allow rolling motion. And a large number of rolling elements capable of circulating in the rolling element circulation path, a stator attached to the track rail, and a mover attached to the moving block in a state of facing the stator via a gap. A linear motor actuator that generates power to cause the moving block to linearly move along the track rail, wherein the rolling element rolling portion of the track rail and the moving block are provided. The row of rolling elements and the linear motor interposed between the load rolling element rolling portions of the rack are separated in the vertical direction in a state where the track rail is mounted on a horizontal mounting surface. Features.

  According to one aspect of the present invention, since the moving block and the linear motor are separated in the vertical direction of the track rail, the linear motor can be attached using the moving block and the lower portion of the track rail effectively in space. For this reason, while being able to achieve size reduction of a linear motor actuator, it can reduce that the magnetic flux of a linear motor acts on a rolling element.

The perspective view of the linear motor actuator of one Embodiment of this invention Side view of the linear motor actuator Front view of the linear motor actuator Front view showing the track rail mounted on the mounting surface Perspective view of moving block (including partial cross-sectional view) Cross section of moving block Sectional drawing which shows a synchronous linear motor ((a) shows the example which attached the coil to the track rail, (b) shows the example which attached the coil to the moving block) Sectional drawing which shows an induction type linear motor ((a) shows the example which attached the coil to the track rail, (b) shows the example which attached the coil to the moving block) Plan view showing another example of metal plate of induction type linear motor

  Hereinafter, a linear motor actuator according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings. FIG. 1 shows a perspective view of the linear motor actuator, and FIG. 2 shows a side view of the linear motor actuator. The linear motor actuator includes a track rail 1, a moving block 2 assembled to the upper flange 1c of the track rail 1 so as to be movable in the longitudinal direction, a linear motor 6 that generates a driving force for linearly moving the moving block 2, Is provided. The track rail 1 is attached to an attachment surface such as a floor, wall, or ceiling of a room, and the moving block 2 is attached to a table that supports a conveyed product, for example.

  FIG. 3 shows a front view of the linear motor actuator. The track rail 1 is formed in an I-shaped cross section having an upper flange 1c to which the moving block 2 is assembled, a lower flange 1a attached to the attachment surface, and a web 1b connecting the upper flange 1c and the lower flange 1a.

  The lower flange 1a is formed in a plate shape whose center in the width direction is slightly thicker than both ends. The lower flange 1a is fixed to the mounting surface. Bolts are not drilled through the lower flange 1a. As shown in FIG. 4, the lower flange 1 a is fixed to the mounting surface 8 by a clamp 7. The clamp 7 is formed in a substantially L shape, and its end engages with the lower flange 1a. When the clamp is tightened with the tightening bolt 9, the lower flange 1 a is fixed to the mounting surface 8. Instead of using the clamp 7, a bolt through hole may be formed in the lower flange 1 a and the lower flange 1 a may be fixed to the mounting surface 8 with the bolt.

  As shown in FIG. 3, the web 1b is erected in the vertical direction from the center portion in the width direction of the lower flange 1a. The thickness of the web 1b is constant in the vertical direction and the depth direction. The web 1b has no through holes such as bolts and screws for fixing the track rail 1 to the mounting surface. The left and right side surfaces of the web 1b are parallel to each other, and the stator 5 of the linear motor 6 is attached to the left and right side surfaces of the web 1b symmetrically. The mover 4 of the linear motor 6 faces the stator 5 of the linear motor 6 through a magnetic clearance. The mover 4 of the linear motor 6 is also attached to the moving block 2 symmetrically with respect to the web 1b. The direction in which the stator 5 and the mover 4 face each other (the direction indicated by the arrow (1) in the figure connecting the center of the stator 5 and the center of the mover 4) is relative to the vertical plane on which the web 1b is disposed. Orthogonal.

  An upper flange 1c having a substantially rectangular cross section is provided at the upper end of the web 1b. The thickness of the upper flange 1c in the vertical direction is thicker than the thickness of the lower flange 1a in the vertical direction, and the width in the horizontal direction of the upper flange 1c is smaller than the width in the horizontal direction of the lower flange 1a. At four corners of the upper flange 1c having a substantially rectangular cross section, four-row ball rolling portions 10 on which balls as rolling elements roll are formed. As shown in FIG. 1, the ball rolling part 10 is formed along the longitudinal direction of the upper flange 1c. The cross-sectional shape of the ball rolling part 10 is formed in a circular arc groove shape having a radius slightly larger than the radius of the ball 14 (see FIG. 5), and the ball 14 and the ball rolling part 10 are in contact at one point.

  The track rail 1 is manufactured, for example, by drawing a steel material and then grinding the ball rolling part 10.

  A hook-shaped moving block 2 is movably assembled to the upper flange 1c of the track rail 1 so as to surround the upper flange 1c. As shown in FIGS. 5 and 6, the moving block 2 is formed with a load ball rolling portion 12 that faces the ball rolling portion 10 of the upper flange 1 c, and penetrates parallel to the load ball rolling portion 12. A no-load return path 13 made of holes is formed. Between the ball rolling part 10 of the upper flange 1c and the loaded ball rolling part 12 of the moving block 2, a large number of rows of balls 14 are interposed so as to be able to roll. The cross-sectional shape of the loaded ball rolling portion 12 is also formed in a circular arc groove shape having a radius slightly larger than the radius of the ball 14, and the ball 14 and the loaded ball rolling portion 12 are in contact at one point. As shown in FIG. 6, the contact angle lines of the upper and lower two-row 14-row rows form, for example, 45 degrees upward and 45 degrees downward with respect to the horizontal direction. Thereby, substantially the same load can be applied to the four directions (radial direction, reverse radial direction, left and right direction) acting on the moving block 2.

  As shown in FIG. 5, a pair of end plates 2b are provided at both ends of the moving block 2 in the moving direction. Each of the pair of end plates 2b is formed with a U-shaped direction change path that connects the ends of the load ball rolling part 12 and the no-load return path 13 that are parallel to each other. A circuit-shaped ball circulation path is constituted by the loaded ball rolling section 12, the no-load return path 13, and the U-shaped direction changing path. When the moving block 2 is linearly moved relative to the track rail 1, a large number of balls 14 roll between the ball rolling portion 10 of the upper flange 1c and the loaded ball rolling portion 12 of the moving block 2. . The ball 14 that has moved to one end of the loaded ball rolling part 12 is scooped up into the U-shaped direction change path, passes through the no-load return path 13 and the opposite direction change path, and then again the load ball rolling path. 12 is returned to the other end.

  As shown in FIG. 5, the moving block 2 is made of a steel moving block body 2a in which the above-described loaded ball rolling part 12 and unloaded return path 13 are formed, and a resin in which the above-described direction changing path is formed. And the end plate 2b. The moving block body 2a is processed with a tap hole or a through hole 15 for attaching the moving block 2 to a table or the like. The moving block 2 includes a nipple 16 for supplying a lubricant to a large number of balls 14, and a ball holding plate that prevents the balls 14 from falling off the moving block 2 when the moving block 2 is removed from the track rail 1. 17 is provided.

  As shown in FIG. 1, a substantially rectangular bracket 18 is attached to the lower surface of the moving block 2. As shown in FIG. 3, the pair of left and right brackets 18 are attached to both ends in the width direction of the moving block 2 through coupling means such as bolts and screws. Tap holes for attaching the brackets 18 are processed on the lower surfaces of both ends of the moving block 2.

  The mover 4 of the linear motor 6 is attached to the inner surfaces of the pair of left and right brackets 18 facing each other. The linear motor 6 including the stator 5 and the movable element 4 is separated from the moving block 2 in the vertical direction, and the linear motor 6 is not disposed between the rows of balls 14 of the moving block 2.

  As the linear motor 6, a synchronous or induction type linear motor is used. FIG. 7 shows an example in which a synchronous linear motor 6 is used. In the case of the synchronous linear motor 6, a permanent magnet / coil is used for the combination of the stator 5 and the mover 4.

  As shown to Fig.7 (a), the three-phase coil 5a is attached to the web 1b of the track rail 1 as the stator 5, for example. A plurality of permanent magnets 4 a that alternately form N poles and S poles in the longitudinal direction of the track rail 1 are attached to the moving block 2 as the mover 4. When a three-phase alternating current is passed through the three-phase coil 5a, a moving magnetic field is generated in the longitudinal direction of the track rail 1. The permanent magnet 4 a attached to the moving block 2 is attracted to the moving magnetic field and moves in the longitudinal direction of the track rail 1. If the three-phase coil 5a is arranged on the track rail 1 side as in this example, there is a merit that cable routing is not necessary.

  FIG.7 (b) shows the example which reversed arrangement | positioning of a three-phase coil and a permanent magnet. In this example, a plurality of permanent magnets 5 b are arranged on the track rail 1, and a three-phase coil 4 b is attached to the moving block 2. In the case of this example, it is possible to correspond to a multi-slide in which a plurality of moving blocks 2 are attached to one track rail 1, and the plurality of moving blocks 2 can be moved for each moving block 2.

  FIG. 8 shows an induction type linear motor 6. In the case of the induction type linear motor 6, an aluminum plate / coil is used for the combination of the stator 5 and the mover 4.

  As shown in FIG. 8A, for example, a three-phase coil 5 c is attached to the web 1 b of the track rail 1 as the stator 5. An aluminum plate 4 c as a mover 4 is attached to the moving block 2. When a three-phase alternating current is passed through the three-phase coil 5c, an induced current is generated in the aluminum plate 4c, and a thrust force that moves the moving block 2 is generated. If the three-phase coil 5c is arranged on the track rail 1 side, there is an advantage that it is not necessary to route the cable.

  FIG. 8B shows an example in which the arrangement of the coil and the aluminum plate is reversed. In this example, an aluminum plate 5 d is disposed on the track rail 1, and a three-phase coil 4 d is disposed on the moving block 2. In the case of this example, it is possible to correspond to a multi-slide in which a plurality of moving blocks 2 are attached to one track rail 1, and the plurality of moving blocks 2 can be moved for each moving block 2.

  FIG. 9 shows another example of the metal plate 21 of the induction type linear motor. The metal plate 21 in this example is formed by joining a copper plate 22 and an aluminum plate 23. The copper plate 22 is formed in a ladder shape, and an aluminum plate 23 is embedded inside the ladder-shaped copper plate 22. That is, the copper plate 22 is composed of two parallel side members and a plurality of crosspieces connecting the side members. The alum plate is accommodated in a rectangular space composed of side members and crosspieces. By combining the copper plate 22 and the aluminum plate 23 as in this example, the induced current flowing through the metal plate 21 can be increased, and the thrust of the linear motor 6 can be improved.

  In order to position the moving block 2, a linear encoder that detects the position of the moving block 2 is attached to the track rail 1, and the current flowing in the three-phase coil is controlled by a driver. When high-precision positioning is not required, a certain amount of current is supplied to the three-phase coil, and when the moving block 2 moves to a predetermined position, the current supplied to the three-phase coil is stopped with a limit switch or the like. Also good.

  As shown in FIG. 3, according to this embodiment, even if there is an error in the mounting surface to which the track rail 1 is mounted, the web 1b of the track rail 1 bends in the left-right direction around the root (arrow ( (Refer to 2)) so that the error of the mounting surface can be absorbed. Since the moving block 2 is assembled to the upper flange 1c of the track rail 1, even if the web 1b is bent, the ball train is not overloaded. At first glance, it seems that the clearance between the stator 5 and the movable element 4 of the linear motor 6 varies as the web 1b bends, but the moving block 2 assembled to the upper flange 1c as the web 1b bends. Since the web 1b is displaced in the bending direction, the relative positions of the stator 5 and the mover 4 do not change so much and the gap between the stator 5 and the mover 4 can be prevented from changing. .

  Since the moving block 2 and the linear motor 6 are separated in the vertical direction of the track rail 1 and the linear motor 6 is attached by effectively using the web 1b of the track rail 1 in space, the linear motor actuator can be reduced in size. . In particular, the linear motor actuator can be miniaturized by making the direction in which the stator 5 and the mover 4 of the linear motor 6 face each other (the direction indicated by the arrow (1) in the figure) perpendicular to the vertical plane on which the web 1b is disposed. In addition, the volume of the linear motor 6 can be maximized below the moving block 2. The linear slide described in Patent Document 1 has the advantage of being able to move the transported object with high accuracy, but is not long enough to absorb the error of the mounting surface to which the track rail is attached. Not suitable for transporting transported objects by stroke. In order to attach a long track rail to the mounting surface, the rail must be able to absorb the error of the mounting surface even if there is an error in the mounting surface.

  Furthermore, by attaching the mover 4 to the moving block 2 via the bracket 18, the mover 4 can be attached to the moving block 2 after the moving block 2 is assembled. Since the moving block 2 can be assembled before being affected by the magnetic flux of the linear motor 6, the moving block 2 can be easily assembled. Here, since the position of the moving block 2 with respect to the track rail 1 is accurately positioned by the row of balls 14, the position of the clearance between the stator 5 and the mover 4 of the linear motor 6 is easy.

  Furthermore, by arranging the linear motor 6 symmetrically with respect to the web 1b of the track rail 1, the attractive force acting between the stator 5 and the movable element 4 of the linear motor 6 can be offset.

  Further, as shown in FIG. 7B, when the permanent magnet 5b as the stator 5 is attached to the web 1b of the track rail 1, the track rail 1 can function as a yoke forming a magnetic circuit.

  In addition, this invention is not limited to the said embodiment, It can change into various embodiment in the range which does not change the summary of this invention.

  For example, the linear motor actuator of the present invention may be used as a single-axis actuator in which one track rail is arranged alone, or used as a two-axis actuator in which two track rails are arranged in parallel. Sometimes it is done. When used as a single-axis actuator, it may be used as a multi-slide in which a plurality of moving blocks are arranged on one track rail. If multiple moving blocks can be moved separately with a single track rail, a single-axis actuator is equivalent to a 2-axis or 3-axis actuator, even if multiple track rails are not stretched around two or three axes. The work to do becomes possible.

  The track rail may not be straight and may be curved. The track rail may be connected in an endless ring shape so that the moving block moves along a circular track. In this case, it becomes possible to deliver a transported object between a plurality of stations arranged along a circular track.

  The track rail is not limited to an I-shaped cross section, and may have a T-shaped cross section. In the case of a T-shaped cross section, the lateral width of the web and the lateral width of the lower flange may be substantially the same.

  The track rail may be mounted not only on a horizontal mounting surface but also on a vertical mounting surface or an inclined mounting surface. In this case, it is only necessary that the ball train and the linear motor are separated in the vertical direction in a state where it is assumed that the track rail attached to the vertical surface or the inclined surface is arranged on the horizontal plane.

  Rollers can be used instead of balls for the rolling elements incorporated in the moving block.

  Since the linear motor actuator of the present invention is suitable for moving a conveyed object with a long stroke, a loading system for loading / unloading a workpiece to / from a machine tool, or automatically storing / removing a stored item in / from a storage location. It can be used as an actuator for automatic warehouses.

DESCRIPTION OF SYMBOLS 1 ... Track rail, 1a ... Lower flange, 1b ... Web, 1c ... Upper flange, 2 ... Moving block, 4 ... Movable element, 5 ... Stator, 6 ... Linear motor, 8 ... Mounting surface, 10 ... Ball rolling part (Rolling element rolling part), 12 ... Loaded ball rolling part (Loaded rolling element rolling part), 14 ... Ball (rolling element), 18 ... Bracket

Claims (6)

A track rail in which rolling element rolling parts are formed along the longitudinal direction;
A rolling block including a rolling element circulation path including a loaded rolling element rolling part facing the rolling element rolling part of the track rail, and a movable block assembled to be movable to the track rail;
A plurality of rolling elements capable of rolling motion between the rolling element rolling part of the track rail and the load rolling element rolling part of the moving block, and capable of circulating in the rolling element circulation path;
A stator attached to the track rail, and a mover attached to the moving block in a state of being opposed to the stator via a gap, and generating power for causing the moving block to linearly move along the track rail. In a linear motor actuator comprising a linear motor,
The row of rolling elements and the linear motor interposed between the rolling element rolling part of the track rail and the load rolling element rolling part of the moving block make the track rail a horizontal mounting surface. A linear motor actuator, wherein the linear motor actuator is separated in a vertical direction in an attached state. The track rail has an upper flange on which the rolling element rolling part is formed, a lower flange attached to a mounting surface, and a web connecting the upper flange and the lower flange,
The moving block is movably assembled to the upper flange of the track rail;
The linear motor actuator according to claim 1, wherein a stator of the linear motor is attached to the web of the track rail. A bracket is attached to the lower surface of the moving block via a coupling means,
The linear motor actuator according to claim 1, wherein the mover of the linear motor is attached to the bracket. The stator is attached to the left and right sides of the web of the track rail symmetrically with respect to the web,
The linear motor actuator according to claim 2, wherein the movable element facing the stator is attached to the moving block symmetrically with respect to the web of the track rail. The linear motor is a synchronous linear motor,
One of the stator or the mover is composed of a plurality of permanent magnets alternately forming N poles and S poles in the longitudinal direction of the track rail,
5. The linear motor actuator according to claim 1, wherein the other of the stator and the mover includes a plurality of coils arranged in a longitudinal direction of the track rail. The linear motor is an induction type linear motor,
One of the stator or the mover comprises a metal plate extending in the longitudinal direction of the track rail,
The other of the stator or the mover is composed of a plurality of coils arranged in the longitudinal direction of the track rail and generating an induced current of the metal plate. Linear motor actuator.

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