JP4580847B2 - Linear motor unit and its combination method - Google Patents

Description

  The present invention relates to a linear motor that obtains a thrust for linear motion by means of a magnetic field of a magnet and a current that flows through a coil, and more particularly to a rod type linear motor that linearly moves a rod.

  The linear motor is obtained by linearly extending a stator side and a rotor side of a rotary motor, and converts electric energy into thrust for linear motion. A linear motor capable of obtaining a linear thrust is used as a uniaxial actuator that linearly moves a moving body.

  If the linear motor is divided into shapes, it can be divided into a rod type and a flat type. A rod type linear motor has a configuration in which a plurality of cylindrical coils are stacked, and a rod having a magnet is inserted into a hole of the stacked coil. For example, when a three-phase current having a phase difference of 120 ° is applied to a plurality of coils divided into three phases of U, V, and W phases, a moving magnetic field that moves in the axial direction of the coil is generated, and the rod is moved by the moving magnetic field. Thrust is obtained and linear motion is performed in synchronization with the speed of the moving magnetic field. On the other hand, the flat type linear motor has a configuration in which a plurality of coils are opposed to a track rail in which a plurality of flat magnets are arranged. The principle that the coil linearly moves relative to the magnet is the same as that of the rod type linear motor. The applicant has proposed, for example, a linear motor described in Patent Document 1 as the rod-type linear motor described above.

JP 2004-248490 A

  If a single-axis actuator can be arranged vertically and horizontally to obtain a multi-axis actuator, a large number of moving bodies can be conveyed at one time, so that the processing speed is increased by the number of axes. For example, a chip mounter (electronic component mounting machine) has multi-axis actuators such as 8-axis and 10-axis in a head axis unit, and conveys and mounts a large number of electronic components at a time. Conventionally, a ball screw mechanism has been used as a driving mechanism for such a multi-axis actuator. However, due to the size of the ball screw and the size of the motor, the distance between the actuators cannot be reduced. On the other hand, the rod type linear motor described above has an advantage that not only can the moving body be conveyed at high speed, but also the size can be reduced. Therefore, the applicant has developed a multi-axis linear motor in which single-axis rod type linear motors are arranged vertically and horizontally. Such a multi-axis linear motor is called a linear motor unit.

  However, when the rod type linear motors were actually arranged, when the rod of one rod type linear motor was moved, the phenomenon that the rod of the next rod type linear motor was caught and moved occurred. This is because when the distance between the adjacent rods is short, the magnetic force attracting the magnets also increases. In order not to cause this phenomenon, the distance between the rods must be increased. If the distance between the rods is increased, the actuator cannot be made compact, as with an actuator using a ball screw mechanism, and the linear motor unit cannot be established.

  Accordingly, an object of the present invention is to provide a combination method of a linear motor unit and a rod type linear motor that can reduce the influence of magnetic force between adjacent rods even if rod type linear motors are arranged close to each other.

In order to solve the above problem, the invention according to claim 1 is a rod having a plurality of magnets laminated so that the same poles face each other, and a pole shoe made of a magnetic material interposed between the plurality of magnets. A plurality of coils surrounding the rod and stacked in the axial direction of the rod, a spacer interposed between the plurality of coils, and covering the plurality of coils and the spacer to form an outer shape of the linear motor A linear motor in which a plurality of rod- type linear motors that linearly move the rod in the axial direction by a magnetic field of the magnet and a current flowing through the coil are combined so that the rod axes are kept parallel to each other. A unit, wherein the housing is formed by insert molding the plurality of coils and the spacer. I made is, moving the one rod-type linear motor of the rod, in a state of being close to rod-type linear motor adjacent to an extent that would moving hung the next rod type linear motor of the rod, the adjacent rod type A magnetic shield plate made of a magnetic material is interposed between the housings of the linear motor, and the magnetic shield plate passes between the housings covering the coil in the axial direction of the rod and from the housing to the axial direction of the rod. The magnetic shield plate is a linear motor unit that makes adjacent rods less susceptible to each other's magnetic field and improves the thrust of the linear motor.

  According to a second aspect of the present invention, in the linear motor unit according to the first aspect, the length of the magnetic shield plate in the axial direction of the rod is one of a pair of adjacent rod type linear motors. In one rod type linear motor, the total length of the rod and the stroke length of the rod is equal to or greater than the total length.

The invention according to claim 3 is the linear motor unit according to claim 1 or 2, wherein the plurality of rod type linear motors are combined in a plurality of stages and a plurality of rows so as to keep the axes of the rods in parallel. The length of the housing in the row direction is shorter than the length in the step direction, and the magnetic shield plate is interposed between the housings adjacent in the row direction .

According to a fourth aspect of the present invention, there is provided a rod having a plurality of magnets laminated so that the same poles face each other, and a pole shoe made of a magnetic material interposed between the plurality of magnets, and surrounding the rod, A plurality of coils stacked in the axial direction of the rod, a spacer interposed between the plurality of coils, and a housing that covers the plurality of coils and the spacer and forms an outer shape of a linear motor, and the magnet A rod type linear motor that combines a plurality of rod type linear motors that linearly move the rod in the axial direction thereof by a magnetic field and a current that flows in the coil so that the axes of the rods are kept parallel to each other , The housing is formed by insert molding the plurality of coils and the spacer. , Moving the one rod-type linear motor of the rod, in a state of being close to rod-type linear motor adjacent to the extent that next to the rod type linear motor of the rod will move to hung, the adjacent rod type linear motor A magnetic shield plate made of a magnetic material is interposed between the housings, and the magnetic shield plate passes between the housings covering the coil in the axial direction of the rod and is exposed from the housing in the axial direction of the rod. And the said magnetic shield board is a combination method of the rod type linear motor which makes the adjacent rods hardly receive the influence of a mutual magnetic field, and improves the thrust of a linear motor.

  According to the first aspect of the present invention, since the magnetic lines of force of the magnet pass through the magnetic shield plate made of a magnetic material, the magnetic lines of force hardly leak to the outside of the magnetic shield plate. Therefore, adjacent rods are not easily affected by each other's magnetic field. In addition, since the magnetic shield plate also serves as a core that strengthens the magnetic field of the coil and magnet inside the magnetic shield plate, the thrust of the rod can be improved in the same manner as a linear motor with a core.

  According to the second aspect of the present invention, since the magnetic shield plate extends over the entire length of the range in which the rod strokes, the influence of the magnetic field on the adjacent rod can be reduced regardless of the position of the rod.

  According to the invention described in claim 3, a multi-axis linear motor unit is obtained.

  According to the fourth aspect of the present invention, since the magnetic lines of force of the magnet of the rod pass through the magnetic shield plate made of a magnetic material, it is difficult to leak out of the magnetic shield plate. Therefore, adjacent rods are not easily affected by each other's magnetic field. In addition, since the magnetic shield plate also serves as a core for strengthening the magnetic field of the coil, the thrust of the rod can be improved.

  Embodiments of the present invention will be described in detail with reference to the accompanying drawings. FIG. 1 is a perspective view of a linear motor unit according to an embodiment of the present invention. This linear motor unit is configured by combining a number of rod type linear motors 1 such that the axis of the rod 2 is parallel to the step direction (vertical direction in the figure) and the column direction (left and right direction in the figure). For example, in this example, two rows and six rows are combined. Each rod type linear motor 1 includes a rod 2 having a magnet 7 and a coil 3 (see FIG. 2) surrounding the rod 2. The combined rod type linear motor 1 is surrounded by a frame member 4 and integrated. The frame member 4 is formed with a coupling protrusion 4a for attaching the linear motor unit to the counterpart component. This linear motor unit is attached to the head shaft of a chip mounter, for example.

  A magnetic shield plate 5 is sandwiched between a pair of adjacent rod type linear motors 1. The magnetic shield plate 5 is also disposed at the end of the rod type linear motor. The magnetic shield plate 5 is made of a magnetic material that is easily magnetized when placed in a magnetic field, such as iron, nickel, chromium, permalloy (nickel (35 to 80%)-iron alloy magnetic material). As in this embodiment, the magnetic shield plate 5 may be sandwiched and fixed between a pair of adjacent rod type linear motors 1 by the frame member 4, or the rod type linear motor 1 may be bonded by means of bonding, bolts or the like. It may be fixed to the side surface.

  In this embodiment, the front shape of the outer shape of each rod type linear motor 1 is formed in a square shape that is short in the column direction and long in the step direction (see FIG. 2), so that the distance between the rods 2 in the column direction is relatively long. While the distance is short, the distance between the rods 2 in the step direction is relatively long. That is, the rods 2 adjacent to each other in the column direction have an effect of magnetic force, whereas the rods 2 adjacent to each other in the step direction hardly influence the magnetic force. Therefore, the magnetic shield plate 5 is interposed only between the rods 2 adjacent in the column direction.

  When the magnetic shield plate 5 is sandwiched between the rod type linear motors 1, the magnetic lines of force of the magnet 7 of the rod 2 pass through the magnetic shield plate 5 of magnetic material. Become. That is, the magnetic field of the magnet 7 of the adjacent rod 2 is shielded for the rod 2 on the opposite side across the magnetic shield plate 5. Therefore, the adjacent rods 2 are hardly affected by each other's magnetic field. Moreover, the magnetic shield plate 5 not only does not adversely affect the magnetic field of the magnet 7 of the rod 2 inside the magnetic shield plate 5 but also has a role of a core that strengthens the magnetic field of the coil 3 and the magnet 7. Therefore, the thrust of the rod 2 can be improved similarly to the linear motor with the core.

  The magnetic shield plate 5 is formed in a flat plate shape elongated in the axial direction of the rod 2. The length of the magnetic shield plate 5 in the axial direction of the rod 2 is equal to or greater than the sum of the total length of the rod 2 and the stroke length of the rod 2 and faces the rod 2 over the entire range in which the rod 2 strokes.

  In FIG. 1, only the portion where the magnetic shield plate 5 is exposed from the rod type linear motor 1 is shown, but actually, the magnet is also applied to the housing 6 (see FIG. 2) portion that covers the coil 3 of the rod type linear motor 1. The shield plate 5 passes. The coil 3 in the housing 6 is a spirally wound copper wire and is not a magnetic material. Since the magnetic field from the magnet 7 of the rod 2 does not change between inside and outside the housing 6, it is necessary to pass the magnetic shield plate 5 through the housing 6 portion. If the magnetic shield plate 5 has only the role of a core, the length corresponding to the portion of the coil 3 may be sufficient. However, the magnetic shield plate 5 is provided not for the role of the core but for the role of making the adjacent rods 2 less susceptible to each other's magnetic field. Therefore, the length of the magnetic shield plate 5 in the axial direction of the rod 2 is set to be equal to or greater than the total length of the rod 2 and the stroke length of the rod 2. The length of the magnetic shield plate 5 in the vertical direction is substantially equal to the height of the housing 6.

  The thicker the magnetic shield plate 5 is, the more effective the magnetic shield is and the adjacent rods 2 are not affected by each other's magnetic field. On the other hand, the thinner the magnetic shield plate 5 is, the more desirable from the demand for miniaturization of the linear motor unit. When the magnetic field analysis of the magnet 7 is performed, the thickness of the magnetic shield plate 5 is set to the minimum thickness within a range in which the adjacent rods 2 are not easily affected by each other's magnetic field.

  The configuration of each rod type linear motor 1 will be described below. FIG. 2 is a perspective view of the rod type linear motor 1. The rod type linear motor 1 obtains a force for movement by the magnetic field of the magnet 7 and the current flowing through the coil 3 as in the case of the rotary motor. Unlike the rotary motor, the rod 2 into which the magnet 7 is inserted penetrates a plurality of linearly arranged coils. When a current is passed through the coil 3, the rod 2 linearly moves in the axial direction according to a law in which the current in the magnetic field receives a force.

  The operating principle of the rod type linear motor 1 will be described. FIG. 3 shows the positional relationship between the magnet 7 and the coil 3 of the rod type linear motor 1. In the hollow space in the rod 2, a plurality of disk-shaped magnets 7 (segment magnets) are laminated so that the same poles face each other, that is, the N pole and the N pole face each other and the S pole and the S pole face each other. Is done. On the other hand, a plurality of coils 3 surrounding the rod 2 are arranged around the rod 2. The three coils 3 form a set of three-phase coils composed of U, V, and W phases. A coil unit is configured by combining a plurality of sets of three-phase coils. When a three-phase current having a phase difference of 120 ° is applied to the plurality of coils 3 divided into the U, V, and W phases, a moving magnetic field that moves in the axial direction of the coil 3 is generated. The magnet 7 of the rod 2 obtains a thrust by this moving magnetic field and performs a linear motion relative to the coil 3 in synchronization with the speed of the moving magnetic field.

  Next, the configuration of each part of the rod type linear motor will be described. As shown in FIG. 2, a coil unit in which a plurality of coils 3 are stacked is covered with a housing 6. The rod 2 is supported by the housing 6 so as to be movable in the axial direction of the rod 2.

  The rod 2 is made of a nonmagnetic material such as stainless steel and has a hollow space inside like a pipe. In this hollow space of the rod 2, as described above, a plurality of disk-shaped magnets 7 (segment magnets) are laminated so that the same poles face each other. A pole shoe 9 (magnetic pole block) made of a magnetic material such as iron is interposed between the magnets 7.

  The coil 3 is a copper wire wound spirally. In this embodiment, in order to suppress the dimension of the housing 6, the coil 3 is set in an injection mold, and the housing 6 is formed by insert molding in which a molten resin or special ceramics flows. When taken out from the mold, the periphery of the coil 3 is covered with the housing. This is because in the linear motor unit using the rod type linear motors 1 side by side, if the dimensions of the rod type linear motors 1 can be reduced, the size can be reduced.

  A material having high mechanical rigidity is used for the housing 6. And since it is necessary to maintain the insulation with the coil 3, a highly insulating material is used. Further, a plurality of fins 6a are formed in the housing in order to improve the heat dissipation of the coil 3.

  The rod 2 is in a floating state in the coil 3 during operation of the rod type linear motor 1. In order to guide the linear movement of the rod 2, a bush 11 is provided. The bush 11 is fixed to end members 12 provided at both ends of the housing 6.

  FIG. 4 shows a coil unit. The coil unit is formed by laminating a plurality of, for example, several tens, one coil 3 in which copper wire is spirally wound. As described above, the coil unit includes the U, V, and W phase coils 3. The lead wires 3a of the coil 3 are connected to each other by a U-phase coil, a V-phase coil, and a W-phase coil. Since adjacent coils 3 need to be insulated from each other, a resin spacer 8 is interposed between the coils 3 as an insulating material. The spacer 8 is formed in an annular shape like the front shape of the coil 3. The principle that the rod 2 moves linearly when a current is passed through the coil 3 is as described above.

  The present invention is not limited to the above embodiment, and can be embodied in various other embodiments without departing from the scope of the present invention. For example, in this embodiment, the rod type linear motors are arranged in the vertical direction and the horizontal direction, but may be arranged in any one of the vertical direction and the horizontal direction, and the axis of the rod is kept parallel. It does not have to be. Further, the magnetic shield plate may be formed in a cylindrical shape surrounding the rod instead of a flat plate shape. In this case, a slit parallel to the axis of the rod is inserted to suppress the eddy current generated in the magnetic shield plate. Furthermore, during the rod stroke, if there is no state where adjacent rods have come out of the housing at the same time (ie, when one rod is out of the housing, the other rod is not out of the housing), Since the magnets of the adjacent rods in the protruding portion do not interfere with each other, the magnetic shield plate may be shortened accordingly. Furthermore, if the rod having a magnet with respect to the coil is a linear motor that linearly moves, the configuration of each part of the rod type linear motor is not limited to the above-described embodiment, and can be variously changed.

The perspective view of the linear motor unit in one Embodiment of this invention. FIG. 2 is a perspective view (including a partial cross-sectional view) of a rod type linear motor incorporated in the linear motor unit. Sectional drawing which shows the coil and magnet of the said rod type linear motor. The perspective view which shows a coil unit.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Rod type linear motor 2 ... Rod 3 ... Coil 5 ... Magnetic shield board 7 ... Magnet

Claims (4)

A plurality of magnets stacked so that the same poles face each other, a rod having a pole shoe made of a magnetic material interposed between the plurality of magnets, and a plurality of layers surrounding the rod and stacked in the axial direction of the rod Coil, a spacer interposed between the plurality of coils, and a housing that covers the plurality of coils and the spacer to form an outer shape of the linear motor, and is configured by a magnetic field of the magnet and a current flowing through the coil. A linear motor unit in which a plurality of rod-type linear motors that linearly move the rod in the axial direction thereof are combined so that the axes of the rods are parallel to each other ;
The housing is formed by insert molding the plurality of coils and the spacer,
When the rod of one rod type linear motor is moved, the rods of the adjacent rod type linear motor are moved close to each other so that the rod of the adjacent rod type linear motor is moved and moved . A magnetic shield plate made of a magnetic material is interposed between the housings ,
The magnetic shield plate passes between the housings covering the coil in the axial direction of the rod, and is exposed from the housing in the axial direction of the rod,
And the said magnetic shield board is a linear motor unit which improves the thrust of a linear motor while making adjacent rods difficult to receive the influence of a mutual magnetic field .   The length of the magnetic shield plate in the axial direction of the rod is the sum of the total length of the rod and the stroke length of the rod in any one of the rod type linear motors of a pair of adjacent rod type linear motors. It is the above, The linear motor unit of Claim 1 characterized by the above-mentioned. The plurality of rod type linear motors are combined in a plurality of stages and a plurality of rows so as to keep the axes of the rods parallel to each other.
The length in the row direction of the housing is shorter than the length in the step direction,
The linear motor unit according to claim 1, wherein the magnetic shield plate is interposed between the housings adjacent in the column direction. A plurality of magnets stacked so that the same poles face each other, a rod having a pole shoe made of a magnetic material interposed between the plurality of magnets, and a plurality of layers surrounding the rod and stacked in the axial direction of the rod Coil, a spacer interposed between the plurality of coils, and a housing that covers the plurality of coils and the spacer to form an outer shape of the linear motor, and is configured by a magnetic field of the magnet and a current flowing through the coil. A rod-type linear motor that combines a plurality of rod-type linear motors that linearly move the rod in its axial direction so that the rod axes are kept parallel to each other ;
The housing is formed by insert molding the plurality of coils and the spacer,
When the rod of one rod type linear motor is moved, the rods of the adjacent rod type linear motor are moved close to each other so that the rod of the adjacent rod type linear motor is moved and moved . A magnetic shield plate made of a magnetic material is interposed between the housings,
The magnetic shield plate passes between the housings covering the coil in the axial direction of the rod, and is exposed from the housing in the axial direction of the rod,
The magnetic shield plate is a method of combining rod-type linear motors that makes adjacent rods less susceptible to mutual magnetic fields and improves the thrust of the linear motor.

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