JP2004129441A - Single-shaft driver - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a single-shaft driver using a linear motor where drive thrust is not fluctuated by the effect of structural components. <P>SOLUTION: The single-shaft driver has a linear motor 12 which has a bar-shaped magnet stator 14 where N poles and S poles are arranged alternately, and a shifter 16 set on the stator and having a coil member and being a circular member capable of shifting along the stator, a fixed table 30; and a mobile table 32 which is supported slidably uniaxially to the fixed table, here either the stator 14 or the shifter 16 is fixed to the fixed table, and the other is fixed to the mobile table. Out of the fixed table and the mobile table, at least the section of the margin of the linear motor 12 is constituted of nonmagnetic material. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a one-axis driving device (also referred to as a linear motion device) using a linear motor, and more particularly to a one-axis driving device that easily suppresses fluctuation in driving thrust due to magnetic force.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, a one-axis driving device (also referred to as a linear motion device) including a fixed table and a movable table that is slidably supported in one axis direction with respect to the fixed table and driven in this direction. Are known. The one-axis driving device is often configured to be driven by various motors (for example, a stepping motor, a linear motor, and the like).
[0003]
FIG. 6 is a perspective view showing an example of the one-axis driving device. In FIG. 1, a one-axis driving device 1 includes a fixed table 2, and a moving table 4 slidably supported on sliding surfaces 3, 3 with respect to the fixed table 2 in the one-axis direction (the direction of the arrow in the drawing). , A motor drive mechanism 5.
[0004]
In the single-axis driving device 1, the screw member 6 of the motor driving mechanism 5 is rotatably fixed to the fixed table 2 via bearings 7, 7, and a nut member (not shown) meshed with the screw member 6 is a moving table. 4 is fixed.
[0005]
By driving the motor 8 fixed to the fixed table 2 in the motor drive mechanism 5, the moving table 4 integrated with the nut member moves back and forth in the direction of the arrow in the figure.
[0006]
As a motor used in such a one-axis driving device, a linear motor having a non-rotating configuration can be applied, unlike the one shown in the figure. Among these linear motors, a linear motor having a stator which is a bar-shaped magnet and a movable member which is a ring-shaped member fitted to the stator and having a coil member and capable of linearly moving along the stator. The motor has features such as low cogging and low speed unevenness, and is on the market (for example, GMC HILLSTONE, trade name: shaft motor).
[0007]
FIG. 7 schematically shows a cross section of such a linear motor 101. A mover 104, which is an annular member having a coil member, is fitted on a stator 102, which is a bar-shaped magnet in which N poles and S poles are alternately arranged in a linear manner. Then, due to the interaction between the magnetic flux of the stator 102 and the current flowing through the coil member of the mover 104, the mover 104 linearly moves along the stator 102 according to Fleming's left-hand rule. A current is supplied to the coil member of the moving element 104 from a drive circuit (not shown).
[0008]
As a technology for improving such a linear motor, a configuration that enables stable and accurate operation has been proposed (Patent Document 1, Patent Document 2, etc.).
[0009]
[Patent Document 1]
JP-A-8-331834
[Patent Document 2]
JP-A-11-150973
[Problems to be solved by the invention]
However, when the above-described conventional linear motor is applied to the one-axis driving device, there is a problem that the driving thrust of the linear motor tends to fluctuate. That is, in the one-axis driving device, the fixed table and the moving table are usually made of a metal material. This is due to reasons such as easiness of processing, high rigidity and high durability. However, when the periphery of the linear motor of the fixed table and the moving table is made of a metal material that is a magnetic material, the magnetic force of the linear motor is affected by the magnetic material of the periphery, and as a result, the driving thrust of the linear motor is reduced. Easy to fluctuate.
[0012]
The present invention has been made in view of such circumstances, and an object of the present invention is to provide a one-axis drive device using a linear motor in which a driving thrust does not fluctuate due to the influence of the components of the one-axis drive device. Aim.
[0013]
[Means for Solving the Problems]
In order to achieve the above object, the present invention has a stator which is a bar-shaped magnet in which N poles and S poles are alternately arranged, and has a coil member fitted to the stator, A linear motor having a movable member that is an annular member movable along the stator, a fixed table, and a movable table slidably supported in one axial direction with respect to the fixed table. A one-axis driving device in which one of the stator and the moving element is fixed to the fixed table, and the other of the stator and the moving element is fixed to the moving table; A single-axis driving device is provided, wherein at least a portion of the periphery of the linear motor is made of a non-magnetic material.
[0014]
According to the present invention, since the peripheral portion of the linear motor is made of a non-magnetic material, the magnetic force of the linear motor is not affected by the magnetic material (metal material or the like) of the peripheral portion. Driving thrust does not fluctuate easily.
[0015]
Further, the present invention has a stator that is a bar-shaped magnet in which N poles and S poles are alternately arranged, and has a coil member that is fitted to the stator and moves along the stator. A linear motor having a movable member which is an annular member capable of moving, a fixed table, and a movable table slidably supported in one axis direction with respect to the fixed table; A single-axis driving device in which one of the children is fixed to the fixed table, and the other of the stator or the moving element is fixed to the moving table, and a sliding surface between the fixed table and the moving table; An axial center of a stator of the linear motor is disposed in substantially the same plane, and a sliding surface of the fixed table and the moving table and the linear motor are separated by a predetermined distance. A shaft drive is provided.
[0016]
According to the present invention, the sliding surfaces of the fixed table and the movable table and the linear motor are separated by a predetermined distance. Therefore, the magnetic force of the linear motor is not affected by the peripheral magnetic material (metal material or the like), and as a result, the driving thrust of the linear motor is less likely to fluctuate. The sliding surface between the fixed table and the moving table and the axis of the stator of the linear motor are arranged in substantially the same plane. Therefore, it is hardly affected by rolling and pitching. In addition, even if there is some influence from yawing, this can be reduced by setting the sliding surface length between the fixed table and the movable table to a predetermined length.
[0017]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, preferred embodiments of a one-axis drive device according to the present invention will be described in detail with reference to the accompanying drawings. FIG. 1 is a sectional view of a first embodiment of a one-axis drive device according to the present invention, FIG. 2 is a perspective view showing an outline of a linear motor 12 used in the one-axis drive device, and FIG. 3 is an enlarged sectional view of a main part of the linear motor 12. FIG.
[0018]
The single-axis driving device 10 includes a fixed table 30, a movable table 32, and linear motion guides 34, 34 for connecting the fixed table 30 and the movable table 32 so as to be slidable in one axial direction (the above members). 2 is not shown in FIG. 2), the linear motor 12 mainly including the stator 14 and the movable member 16, fixing hardware 20 for fixing both ends of the stator 14 to the fixed table 30, and the movable member 16. A cable carrier 22 for supplying power, an encoder 24 and an encoder scale 26 for detecting the position of the moving member 16 in one axial direction, and a limit sensor 28 provided near both ends of the stator 14 for detecting an end limit of the moving member 16. , 28.
[0019]
The moving element 16 of the linear motor 12 is fixed to the moving table 32, the encoder 24 is fixed to the moving table 32, and the encoder scale 26 is fixed to the fixed table 30.
[0020]
The linear motion guide 34 has a long rail-shaped fixed portion 34A and a moving portion 34B, and the moving portion 34B is slidably supported in one axial direction with respect to the fixed portion 34A. For such a sliding mechanism, a mechanism such as a rolling guide (by a ball or a roller), a sliding guide, or the like can be employed. As such a linear motion guide 34, for example, a product name: LM guide manufactured by THK can be used. Note that a configuration in which the moving table 32 is directly supported on the fixed table 30 so as to be slidable in one axial direction without using the linear motion guide 34 may be adopted.
[0021]
Here, of the fixed table 30 and the moving table 32, at least the peripheral portion of the linear motor 12 needs to be made of a non-magnetic material. In the present embodiment, all parts of the fixed table 30 and the movable table 32 are made of a non-magnetic material. Various ceramics can be preferably used as such a non-magnetic material. In addition, various resin materials, particularly, engineering plastics and the like can be preferably used as long as the modulus of longitudinal elasticity is a predetermined value or more. In addition, other non-magnetic materials can also be used.
[0022]
Next, details of the linear motor 12 will be described with reference to FIG. The linear motor 12 is a so-called shaft type linear motor. The linear motor 12 has a stator 14 which is a straight rod-shaped shaft member on which a field magnet is formed as described above, and a movable member 16 which is an annular member having a coil member as a main part. It is constituted by being done.
[0023]
The stator 14 can be machined and is made of a magnetizable material, for example, an Fe—Cr—Co-based metal, and has a circular cross section. Further, the stator 14 is magnetized so as to have a magnetic flux distribution of a uniform pitch, preferably a substantially rectangular shape, along the longitudinal direction. As a result, the stator 14 is formed with a driving magnetized portion in which N poles and S poles are alternately arranged with the same magnetic pole width P along the longitudinal direction, and this serves as a field magnet. . This magnetic pole width P can be, for example, 30 mm.
[0024]
The coil member 40 of the mover 16 is composed of two coil groups (a first coil group and a second coil group), each of which includes three coils of the U-phase, the V-phase, and the W-phase. The first group of coil groups includes coils U1, V1, and W1, and is arranged in this order in the longitudinal direction of the stator 14. The second set of coil groups includes coils U2, V2, and W2, and is arranged in this order in the longitudinal direction of the stator 14. Each of these coils is formed to have a width of 1/3 of the magnetic pole width P.
[0025]
These coils constituting the coil member 40 of the moving element 16 are fixed and integrated so that the outer peripheral surface thereof is coated with an adhesive. The coil member 40 is incorporated in the hollow portion of the hollow rectangular parallelepiped movable element frame 42 and is integrally supported on the inner peripheral surface of the movable element frame 42.
[0026]
Bearing portions 44, 44 that are fitted to the stator 14 and slidable on the stator 14 are provided at both left and right end portions of the slider frame 42 of the slider 16. By the action of the bearings 44, 44, the moving element 16 can move smoothly along the stator 14.
[0027]
Then, due to the interaction between the magnetic flux of the stator 14 and the current flowing through the coil member 40 of the mover 16, the mover 16 linearly moves along the stator 14 according to Fleming's left-hand rule. A current is supplied to the coil member 40 of the movable element 16 from a drive circuit (not shown) via the cable bear 22.
[0028]
In addition, other configurations of the single-axis driving device 10 (the fixing bracket 20, the cable carrier 22, the encoder 24, the encoder scale 26, and the limit sensor 28) are all publicly known, and thus the description thereof is omitted.
[0029]
Although the outline of the one-axis driving device 10 is not shown, the overall configuration is substantially the same as that of the conventional one-axis driving device 1 shown in FIG. Only the points that have been replaced by
[0030]
According to the single-axis driving device 10 having the above-described configuration, the peripheral portion (the fixed table 30 and the movable table 32) of the linear motor 12 is made of a non-magnetic material. As a result, the driving thrust of the linear motor 12 hardly fluctuates.
[0031]
The application of the one-axis driving device 10 having the above-described configuration includes, for example, a use in a driving unit such as a surface roughness measuring device, a contour shape measuring device, a roundness measuring device, and a three-dimensional coordinate measuring device. When used in such an application, the linear motor 12 is characterized in that maintenance is unnecessary, there is no wear portion, low vibration driving is possible, a speed range can be widened, high rigidity, and the structure is simple. And advantageous effects such as no backlash are obtained.
[0032]
Next, another preferred embodiment of the one-axis drive device according to the present invention will be described in detail with reference to the accompanying drawings. FIG. 4 is a sectional view of a second embodiment of the one-axis driving device according to the present invention, and FIG. 5 is a perspective view of the same. Note that the same or similar members as those of the first embodiment (FIGS. 1 to 3) are denoted by the same reference numerals and description thereof will be omitted.
[0033]
The difference of the present embodiment from the first embodiment lies in the arrangement position of the linear motor 12. That is, in the first embodiment, the linear motor 12 is disposed between the linear motion guides 34, 34 in parallel with the linear motion guides 34, 34, but in the second embodiment, the linear motor 12 is The linear motion guides 34, 34 are disposed at a predetermined distance from the linear motion guides 34, 34 in parallel with the linear motion guides 34, 34.
[0034]
In the first embodiment, the moving element 16 is fixed to the moving table 32. In the present embodiment, the moving element 16 is fixed to a connecting plate 36 extending horizontally from the moving table 32. I have. It is preferable that the length (uniaxial driving direction) of the connecting plate 36 be as short as possible to fix the moving member 16.
[0035]
Further, a portion of the fixed table 30 facing the linear motor 12 is cut out in a U-shape except for a portion to which the fixing brackets 20 are fixed.
[0036]
According to the single-axis driving device 11 having the above-described configuration, even when the fixed table 30 and the movable table 32 are formed of a magnetic material (such as a metal material), the magnetic material hardly exists at the peripheral portion of the linear motor 12. In addition, the magnetic force of the linear motor is not affected by the peripheral material, and as a result, the driving thrust of the linear motor 12 is less likely to fluctuate. Even if the connecting plate 36 is made of a magnetic material (such as a metal material), the magnetic force of the linear motor is less likely to be affected by this if the area is minimized.
[0037]
Further, as described above, the sliding surface between the fixed table 30 and the moving table 32 and the axis of the stator 14 of the linear motor 12 are disposed in substantially the same plane. Therefore, it is hardly affected by rolling and pitching. In addition, even when the fixed table 30 and the movable table 32 have a predetermined sliding surface length, this can be reduced even if there is some influence of yawing.
[0038]
As described above, the example of the embodiment of the one-axis driving device according to the present invention has been described. However, the present invention is not limited to the example of the above-described embodiment, and various modes can be adopted. For example, in the embodiment (first and second), a configuration in which two linear motion guides 34 are provided is employed, but a configuration in which only one linear motion guide 34 is provided may be employed.
[0039]
Further, as described above, a configuration in which the movable table 32 is directly supported on the fixed table 30 so as to be slidable in one axial direction without providing the linear motion guide 34 may be adopted.
[0040]
Further, when such a linear motor 12 is applied to the one-axis driving device 10 and used while being inclined with respect to the horizontal, the driving thrust varies due to the weight of the moving member 16. Further, if the energized state of the movable element 16 is maintained in order to prevent the movable element 16 from dropping in such a state, heat is generated in the movable element 16, and the generated heat easily causes a dimensional error of the entire apparatus. The following configuration can be adopted to suppress these problems.
[0041]
That is, the stator 14 is a bar-shaped magnet in which N poles and S poles are alternately arranged in a straight line, and is fitted to the stator 14 and has a coil member 40. A single-axis drive device using a linear motor 12 having a movable member 16 which is an annular member capable of linear movement, wherein a balance weight is disposed so as to be balanced with the movable member 16. It is a driving device.
[0042]
Here, the "balance weight" is "a weight added to remove unbalance of a rotating body in a grinding process or the like. It is used to balance with the own weight of a cross rail of a portal type machine tool or a spindle head of a boring machine. (Writing Dictionary of Cutting, Grinding and Polishing, edited by the Japan Society for Abrasive Processing, 1995, published by the Industrial Research Council), but in this specification, the latter is used in the latter sense. I do.
[0043]
According to such a configuration, when the moving member 16 has its own weight or another constituent member (the moving table 32 in this example) is attached to the moving member 16, the balance can be achieved by the balance weight having substantially the same weight as these. . Therefore, there is no influence of the weight of the movable member 16 or the like, the driving thrust is not changed, and no dimensional accuracy error due to heat generation or the like occurs.
[0044]
In such a configuration, it is preferable that the weight of the balance weight is substantially equal to the total value of the weight of the moving element 16 and the weight of the moving table 32. As described above, the balance can be achieved by the balance weight having substantially the same weight as the own weight of the movable element or the like. Therefore, the driving thrust due to the weight of the moving element or the like is not changed, and no dimensional accuracy error occurs.
[0045]
Further, in such a configuration, it is preferable that the weight of the balance weight is within 20% of the total value of the weight of the moving element and the weight of the moving table 32. If the weight of the balance weight is within such a range, the variation of the driving thrust due to the weight of the moving element or the like often becomes an allowable range, and a dimensional accuracy error hardly occurs.
[0046]
In such a configuration, the balance weight is connected to the moving element 16 by the winding motion transmitting member via a winding motion transmitting supporting member provided near one end or both ends of the linear motor 12. Is preferred. In this way, if the balance weight is connected to the movable element 16 by the wrapping motion transmitting member via the wrapping motion transmitting support member, the balance can be easily obtained.
[0047]
The “wrapping motion transmitting member” is a mechanical element in the wrapping transmission in mechanics, and generally corresponds to a belt, a chain, a wire, or the like. The “winding motion transmission support member” is also a mechanical element in the wrapping transmission, and generally corresponds to a pulley, a belt wheel, a sprocket, or the like.
[0048]
【The invention's effect】
As described above, according to the present invention, since the periphery of the linear motor is made of a non-magnetic material, the magnetic force of the linear motor is not affected by the magnetic material (metal material or the like) of the periphery. As a result, the driving thrust of the linear motor hardly fluctuates.
[0049]
Further, according to the present invention, the fixed table and the movable table are separated from the linear motor by a predetermined distance. Therefore, the magnetic force of the linear motor is not affected by the peripheral magnetic material (metal material or the like), and as a result, the driving thrust of the linear motor is less likely to fluctuate. Further, the sliding surface between the fixed table and the moving table and the axis of the stator of the linear motor are arranged in substantially the same plane. Therefore, it is hardly affected by rolling and pitching. In addition, even if there is some influence from yawing, this can be reduced by setting the sliding surface length between the fixed table and the movable table to a predetermined length.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of an embodiment of a single-axis drive device according to the present invention. FIG. 2 is a perspective view showing an outline of a linear motor used in the single-axis drive device. FIG. FIG. 4 is a cross-sectional view of another embodiment of the single-axis driving device according to the present invention; FIG. 5 is a perspective view of another embodiment of the single-axis driving device according to the present invention; FIG. FIG. 7 is a cross-sectional view showing an outline of a linear motor.
10, 11: single-axis drive device, 12: linear motor, 14: stator, 16: mover, 20: fixing bracket, 22: cable carrier, 24: encoder, 26: encoder scale, 28: limit sensor, 30 ... Fixed table, 32: moving table, 34: linear guide, 36: connecting plate

Claims (2)

A stator that is a bar-shaped magnet in which N poles and S poles are alternately arranged; and an annular member that is fitted to the stator and has a coil member and that can move along the stator. A linear motor having a mover,
A fixed table,
A movable table supported slidably in one axis direction with respect to the fixed table,
A one-axis drive device in which one of the stator or the mover is fixed to the fixed table, and the other of the stator or the mover is fixed to the movable table,
A one-axis drive device, wherein at least a portion of the fixed table and the movable table at the periphery of the linear motor is made of a non-magnetic material. A stator that is a bar-shaped magnet in which N poles and S poles are alternately arranged; and an annular member that is fitted to the stator and has a coil member and that can move along the stator. A linear motor having a mover,
A fixed table,
A movable table supported slidably in one axis direction with respect to the fixed table,
A one-axis drive device in which one of the stator or the mover is fixed to the fixed table, and the other of the stator or the mover is fixed to the movable table,
The sliding surface between the fixed table and the moving table and the axis of the stator of the linear motor are disposed in substantially the same plane, and the sliding surface of the fixed table and the moving table and the linear motor Are arranged at a predetermined distance from each other.

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