JP5113436B2 - Linear motor drive shaft feeder - Google Patents

Description

  The present invention relates to a linear motor-driven shaft feeding device used for table feeding in a machine tool, a semiconductor manufacturing apparatus, or the like.

  2. Description of the Related Art Conventionally, there is an axial feed device that uses a linear motor used for table feed as a drive source, such as a machine tool or a semiconductor manufacturing apparatus. The field portion of the linear motor includes a permanent magnet so that adjacent magnetic poles are alternately different along a magnetic field yoke made of a magnetic material, and the armature portion of the linear motor has a core made of a magnetic material and a conductor. And a wound coil. In the shaft feeding device, the field portion and the armature portion of the linear motor are arranged with a mechanical gap slidable by linear motion guide means such as a linear guide component.

  In the linear motor, particularly in recent years, a high-performance magnet having a high residual magnetic flux density and a high coercive force, such as a rare earth magnet, has been actively used as a means for forming the magnetic pole of the field portion. In order to obtain high thrust, the armature part and the field part of the linear motor have a magnetic gap as small as possible and are arranged, for example, around 1 mm (such as a stainless steel cover or mold on the armature part or field part). If the protective member is provided, the mechanical gap is about 0.5 mm). Since the armature part and the field part are arranged with such a fine magnetic gap, it is known that a magnetic attractive force stronger than the thrust obtained acts between them.

  The force acting between the guide block and the guide rail of the linear guide that linearly guides the armature part and the field part includes the magnetic attraction force in addition to the gravity of the load carried by the linear motor and the external force. And the frictional resistance increases. Since this frictional resistance force is applied in the direction opposite to the moving direction when the linear motor is accelerated, there is a problem in that the acceleration thrust is reduced.

  There is also a problem that the life of the linear guide is reduced due to the sliding friction between the guide block and the guide rail.

  As a solution to these problems, direct measures have been taken to improve the internal structure of the linear guide and reduce the frictional resistance against the load. More effective improvements have been studied.

  For example, in Patent Document 1, a magnetic repulsion member including a permanent magnet configured so that the same magnetic poles are opposed to each other is opposed to the upper surface of the fixed body and the lower surface of the movable body along the moving direction of the linear motor. An example in which the magnetic attraction force of the linear motor is offset and reduced by mounting is disclosed.

  Further, for example, in Patent Document 2, it is possible to reduce the magnetic attraction force of the linear motor in an offset manner, and to reduce the load component acting in the direction intersecting with the thrust as required. An example in which magnetic force generating means for reducing the frictional resistance generated in the linear guide means such as the above is disclosed.

  For example, Patent Document 3 discloses an example of a double-sided linear motor in which field portions are arranged on both sides of an armature portion of a linear motor so that magnetic attraction force cancels out.

JP 2001-298951 A (page 3-4, FIGS. 1 to 4) JP-A-9-140118 (page 3-5, FIGS. 1-7) Patent No. 3786150 (page 3-4, FIG. 1 to FIG. 5)

  However, since Patent Document 1 requires a magnetic repulsion member, there is a problem that the configuration of the mechanical device itself increases in size and weight.

  Similarly, since Patent Document 2 requires a magnetic force generating means, there is a problem that the configuration of the mechanical device itself is increased in size and weight.

  Moreover, in the said patent document 3, although the magnetic attraction force was canceled, the problem that the frictional resistance force by the load which the load of a linear motor exerts on a linear guide component was not reduced remained.

  The present invention has been made to solve the above-described problems, and can reduce the frictional resistance generated by the linear guide, increase the acceleration thrust, and extend the life of the linear guide. It is an object of the present invention to provide a linear motor driven shaft feeding device.

A linear motor-driven shaft feeding device according to the present invention includes a pair of field magnet portions having permanent magnets so that adjacent magnetic poles are alternately different along a magnetic field yoke made of a magnetic material, and the field magnet Between the pair of field portions arranged in parallel along the yoke, an armature portion having a coil on a core made of a magnetic material is mechanically fastened to the armature portion or the field portion. A linear motor-driven shaft feeding device in which the armature part and the field part are slidably arranged so as to be linearly guided in a direction along the field yoke by the linear guide formed;
The linear guide is composed of a guide rail and a guide block installed so as to press each other,
A direction parallel to the gap facing surface between the armature portion and the field magnet portion and perpendicular to the linear motion guiding direction is the A direction,
Of the permanent magnet and the core, the one disposed on the guide rail side is the first magnetic body, the one disposed on the guide block side is the second magnetic body,
The first magnetic body so that the center of the A direction length of the first magnetic body is shifted in the direction from the guide rail toward the guide block with respect to the center of the A direction length of the second magnetic body. It was placed,
The distance between the center of the length of the second magnetic body in the A direction and the center of the length of the first magnetic body in the A direction is defined as a shift amount x [mm], and the length of the second magnetic body in the A direction is Lm [ mm]
0 <x / Lm ≦ 0.78
Within the range that satisfies the above.

  According to the linear motor drive shaft feed device of the present invention, the load on the linear guide is reduced, so that the frictional resistance generated by the linear guide can be reduced and the acceleration thrust output by the linear motor can be increased. At the same time, the life of the linear guide can be extended.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
Embodiment 1 FIG.
1, 2 and 3 are sectional views showing Embodiment 1 of the linear motor drive shaft feeding device according to the present invention, as seen from the moving direction of the linear motor. FIG. 4 is a plan view taken in the direction of arrow B in FIGS. 1, 2, and 3. 1, 2, and 4, the field portion 30 of the linear motor 100 is made of a magnetic material so that magnetic poles adjacent to each other in the moving direction along the field yoke 3 made of a magnetic material are alternately different from each other. Magnets 4a and 4b are provided, and an armature portion 20 of the linear motor 100 is housed in a casing 10 with a coil 7 on a core 2 made of a magnetic material. Although the core 2 is shown as a split core, the present invention does not depend on this. The base 6 is substantially U-shaped and includes a guide rail 8b. The field portion 30 including the permanent magnet 4 of the linear motor 100 in the field yoke 3 is provided on the guide rail 8b side of the linear guide 8 (base 6). Side) with bolts (not shown). The top plate 9 is attached to the guide block 8a supported and guided by the guide rail 8b, and is supported and guided by the guide rail 8b of the linear guide 8. The armature portion 20 having the core 2 in the casing 10 is attached to the top plate 9 on the guide block 8a side by bolts or the like, and the armature portion 20 is slidable with a field gap portion 30 and a mechanical gap 5. Is arranged. Moreover, in this Embodiment 1, the guide rail 8b and the guide block 8a are arrange | positioned so that it may mutually press.

In FIG. 1, the permanent magnet 4 of the field part 30 is arranged as the first magnetic body on the guide rail 8b side (base 6 side), and the core 2 of the armature part 20 is arranged on the guide block 8a side (top plate 9 side). It arrange | positions as a 2nd magnetic body.
In FIG. 3, the first magnetic body disposed on the guide rail 8b side (base 6 side) is the core 2 of the armature portion 20, and the second magnetic body disposed on the guide block 8a side (top plate 9 side) is the field. This is an example in which the permanent magnet 4 of the portion 30 is used, and in the present invention, either the configuration of FIG. 1 or FIG. 3 may be used.

  1, 2 and 3, the two member bases 1 (6a, 6b) are combined. However, an integrally machined base may be used, and the U-shape is an example and is designed in another shape. Sometimes it is done.

  Furthermore, when the direction A is parallel to the opposing surfaces of the armature part 20 and the field part 30 and is perpendicular to the moving direction, the permanent magnet 4 and the core 2 have a length Lm in the A direction of the permanent magnet 4. The center M and the core 2 constituting the armature portion 20 are arranged so as to be shifted by a shift amount x so as not to coincide with the center P of the length Lp in the A direction of the core 2.

FIG. 5 is a diagram for explaining the relationship between the shift position between the center M of the length Lm in the A direction of the permanent magnet 4 and the center P of the length Lp in the A direction of the core 2 constituting the armature portion 20. In FIG. 5, the gravity of the load 11, the top plate 9, and the guide block 8a is shown as an example of the magnetic attractive forces 200a and 200b applied to the core, the vector sum 200 thereof, and the external force 300. As shown in FIG. 5, the center P of the length A in the core 2 constituting the armature portion 20 is mechanically connected to the armature portion 20 with respect to the center M of the length A in the permanent magnet 4. The external force applied to the fastened guide block 8a is shifted in the direction of the A-direction component vector sum 300. That is, the center of the length in the A direction of the permanent magnet 4 of the field magnet portion 30 as the first magnetic body is set to the guide rail with respect to the center of the length in the A direction of the core 2 of the armature portion 20 as the second magnetic body. The permanent magnet 4 is arranged so as to be displaced in the direction from 8b toward the guide block 8a (the direction of the vector sum 200).

  FIG. 6 is a diagram showing the relationship between the deviation amount and the sum of the A direction component vectors of the magnetic attractive force. In FIG. 6, the horizontal axis is expressed by normalizing by dividing the deviation amount x by the length Lm in the A direction of the permanent magnet 4. As shown in FIG. 6, if the magnetic attraction forces 200 a and 200 b are arranged in a shifted manner, the vector sum 200 of the magnetic attraction forces in the A direction changes depending on the center shift amount x, When the displacement amount x is increased, the sum 200 of the magnetic attractive force in the A direction is increased.

  According to this configuration, since the external force 300 and the vector sum 200 of the magnetic attraction force in the A direction are opposite to each other, the guide rail 8b and the guide block 8a are not pressed against each other. Since the load is offset or reduced, the frictional resistance generated by the linear guide 8 can be reduced, the acceleration thrust during conveyance can be increased, and the life of the linear guide 8 can be extended.

  Moreover, since the said effect is acquired by adjusting the positional relationship of the armature part 20 and the field part 30 of the linear motor 100, the effect of a space saving can also be acquired and size reduction of a mechanical apparatus is realizable. Become. The direction component perpendicular to the A direction of the magnetic attractive forces 200a and 200b is offset and reduced by the fact that the armature part 20 is at the approximate center of the field part 30 disposed on both sides.

  7 and 8 are cross-sectional views for explaining the relationship between the deviation amount x and the thrust generated by the linear motor. As shown in FIG. 7, when the deviation amount x increases, the area N that is not opposed to the permanent magnet 4 even on the gap facing surface of the core 2 increases, and as shown in FIG. The amount of magnetic flux linked to the coil 7 of the armature portion 20 is lower than that in the case where the center M of the A direction length Lm of 4 and the center P of the A direction length Lp of the core 2 coincide with each other. The thrust generated is reduced. For this reason, from the viewpoint of the thrust generated by the linear motor, it can be said that the deviation x is desirably as small as possible. On the other hand, in FIG. 6, the A-direction component vector sum of the magnetic attractive force becomes a maximum in the vicinity of x / Lm = 0.78. That is, the vector sum of the magnetic attractive force in the A direction in the range of 0.78 <x / Lm can be realized even when 0 <x / Lm ≦ 0.78. From the above, it is desirable that the deviation amount x is in the range of 0 <x / Lm <0.78.

  More preferably, the base 6 is designed by adjusting the shift amount x so that the sum 200 of the magnetic attraction force in the A direction and the external force 300 are balanced, the linear guide 8 is selected, and the shape of the top plate 9 is designed. It is desirable to do.

  In FIG. 1, the top plate 9 and the guide block 8a are fastened. However, as shown in FIG. 2, the above effect can be obtained even when the top plate 9 and the guide rail 8b are fastened. Is self-explanatory. Further, as shown in FIG. 3, it is obvious that the above effect can be obtained even when the armature portion 20 is fastened to the base 6 and the field portion 30 is fastened to the top plate 9.

  In the first embodiment, the case where the guide rail 8b and the guide block 8a are installed so as to press each other has been described. However, when the apparatus is used with the top 9 suspended from the ceiling, etc. The guide rail 8b and the guide block 8a are installed so as not to push each other. In such a case, the center of the length in the A direction of the permanent magnet 4 as the first magnetic body is shifted from the guide block 8a to the guide rail with respect to the center of the length in the A direction of the yoke 2 as the second magnetic body. By arranging the permanent magnet 4 so as to be displaced in the direction toward 8b, the above effect can be obtained.

Embodiment 2. FIG.
9 and 10 are sectional views showing a second embodiment of the linear motor drive shaft feeding device according to the present invention, as seen from the moving direction of the linear motor. In FIG. 9, the basic configuration is the same as in FIGS. 1, 2 and 3, and different parts will be described. In FIG. 9, the length Lm in the A direction of the permanent magnet 4 is configured to be longer than the length Lp in the A direction of the core 2. In FIG. 10, the length Lp in the A direction of the core 2 is configured to be longer than the length Lm in the A direction of the permanent magnet 4.

  In the first embodiment, there is a region N that is not opposed to the permanent magnet 4 even on the gap facing surface of the core 2 (see FIG. 7). Under such circumstances, the center M of the A direction length Lm of the permanent magnet 4 and the center P of the A direction length Lp of the core 2 coincide with each other in the amount of magnetic flux interlinking with the coil 7 of the armature unit 20. It will be lower than the case (see FIG. 8). In other words, in FIG. 8, the magnetic flux F based on the permanent magnet 4 is almost linked to the core 2, but in the state of FIG. 7, more leakage magnetic flux that is not linked to the core 2 is generated than in FIG. Due to this leakage flux, the thrust generated by the linear motor 100 is reduced. In the second embodiment, in order to compensate for this leakage magnetic flux, the length Lm in the A direction of the permanent magnet 4 is made larger than the length Lp in the A direction of the core 2, or the length Lp in the A direction of the core 2 is made permanent. The magnet 4 is made larger than the length Lm in the A direction.

  11 and 12 are cross-sectional views for explaining the operation in the second embodiment. As shown in FIGS. 11 and 12, the leakage magnetic flux FL is generated, but the leakage magnetic flux due to the region N as shown in FIG. 7 can be prevented and the acceleration thrust of the linear motor 100 is increased. Can do.

  In addition, when the length Lp in the A direction of the core 2 is longer than the length Lm in the A direction of the permanent magnet 4 as shown in FIG. 10, the acceleration thrust of the linear motor 100 can be increased in the same manner. .

  Even in the above configuration, the external force applied to the guide block 8a mechanically fastened to the armature portion 20 with the center P of the length Lp in the A direction of the core 2 relative to the center M of the length Lm in the A direction of the permanent magnet 4 is also achieved. By shifting in the direction of the A-direction component vector, the same effect as in the first embodiment can be obtained.

  Preferably, it is desirable that the opposing surface of the core 2 and the permanent magnet 4 having a short length in the A direction is opposed to the other across the entire surface. This is because the amount of magnetic flux interlinking with the coil 7 of the armature portion 20 is equal to the amount of magnetic flux when the center M of the A direction length Lm of the permanent magnet 4 coincides with the center P of the A direction length Lp of the core 2. This is because the same amount can be obtained and the same thrust can be obtained.

  More preferably, it is desirable that the length Lp in the A direction of the core 2 is shorter than the length Lm in the A direction of the permanent magnet.

  The reason will be described below. Even if either Lp or Lm is configured to be short, the amount of magnetic flux interlinked with the coil 7 can be designed to be equal. At this time, the current value for obtaining a constant thrust is also equivalent. However, the electrical resistance of the coil 7 depends on the length Lp of the core 2 in the A direction, and the electrical resistance is smaller when Lm> Lp. Therefore, the loss in the electric resistance of the linear motor 100 (square of the square current × electric resistance) is also smaller when Lm> Lp. In other words, the reason why Lm> Lp is preferable is that the loss in the electric resistance of the linear motor 100 is smaller when Lm> Lp than when Lm <Lp. This is because the temperature rise can be reduced.

  More preferably, as indicated by line E in FIG. 12, the end surfaces of the core 2 and the permanent magnet 4 in the A direction, which are on the direction side of the sum of the A direction component vectors of the external force 300, substantially coincide with each other. It is desirable to do. This is because the amount of magnetic flux interlinking with the coil 7 of the armature portion 20 is the same as when the center M of the A direction length Lm of the permanent magnet 4 coincides with the center P of the core 2 in the A direction length Lp. This is because the amount of use of the permanent magnet 4 can be suppressed and the increase in the weight of the linear motor driven shaft feeder can be suppressed while the same thrust force can be obtained.

  More preferably, the range is 1 <Lm / Lp ≦ 1.34. The reason why this range is preferable will be described below. FIG. 13 is a vector in the A direction of the magnetic attractive force in a configuration in which Lm> Lp and the end surfaces in the direction of the A direction component vector of the external force 300 substantially coincide with each other in the A direction end surfaces of the core 2 and the permanent magnet 4. It is a figure which shows the relationship between the sum, Lm, and Lp, a horizontal axis is the value which took Lp by using the ratio of Lm and Lp as a denominator, and the vertical axis shows the vector sum of the magnetic attraction force in the A direction. ing. As shown in FIG. 13, the vector sum in the A direction of the magnetic attractive force is a maximum when Lm / Lp = 1.34. For this reason, it can be said that it is desirable to design in the range of 1 <Lm / Lp ≦ 1.34 in order to minimize the increase in the weight of the linear motor-driven shaft feeding device as described above.

  INDUSTRIAL APPLICABILITY The present invention can be effectively used for a linear motor-driven shaft feeding device used for table feeding such as a machine tool and a semiconductor manufacturing apparatus.

1 is a cross-sectional view showing a first embodiment of a linear motor-driven shaft feeding device according to the present invention. 1 is a cross-sectional view showing a first embodiment of a linear motor-driven shaft feeding device according to the present invention. 1 is a cross-sectional view showing a first embodiment of a linear motor-driven shaft feeding device according to the present invention. It is a top view of the arrow B of FIG.1, FIG2 and FIG.3. It is a figure explaining the relationship of the shift position of the center M of A direction length Lm of the permanent magnet 4, and the center P of A direction length Lp of the core which comprises an armature part. It is a figure which shows the relationship between deviation | shift amount and the A direction component vector sum of magnetic attraction force. It is sectional drawing explaining the relationship between deviation | shift amount x and the generated thrust of a linear motor. It is sectional drawing explaining the relationship between deviation | shift amount x and the generated thrust of a linear motor. It is sectional drawing which shows Embodiment 2 of the axial feed apparatus of the linear motor drive which concerns on this invention. It is sectional drawing which shows Embodiment 2 of the axial feed apparatus of the linear motor drive which concerns on this invention. It is sectional drawing explaining the effect | action in this Embodiment 2. FIG. It is sectional drawing explaining the effect | action in this Embodiment 2. FIG. Lm> Lp, the vector sum in the A direction of the magnetic attraction force in the A direction end surfaces of the core 2 and the permanent magnet 4 and the end surfaces in the direction of the A direction component vector sum of the external force 300 substantially coincide with each other. It is a figure which shows the relationship with Lp.

2 cores, 3 field yokes, 20 armature parts, 30 field parts, 4, 4a permanent magnets,
5 Mechanical gap, 6 base, 6a base 1, 6b base 2, 7 coil,
8 Linear guide, 8a Guide block, 8b Guide rail, 9 Top plate,
10 casing, 11 transport load, 20 armature part, 30 field part,
100 linear motor, 200 sum of magnetic attraction vector,
200a, 200b Magnetic attraction force, 300 external force, center of length of P core in A direction,
M Center of length of magnet in A direction, F Magnetic flux flow based on permanent magnet, FL leakage magnetic flux.

Claims (6)

A pair of field portions provided with permanent magnets so that adjacent magnetic poles are alternately different poles along the field yoke made of a magnetic material, and the pair of fields arranged in parallel along the field yoke A direction along the field yoke by a linear guide mechanically fastened to the armature part or the field part. A linear motor driven shaft feeding device in which the armature portion and the field portion are slidably arranged so as to be guided in a linear motion,
The linear guide is composed of a guide rail and a guide block installed so as to press each other,
A direction parallel to the gap facing surface between the armature portion and the field magnet portion and perpendicular to the linear motion guiding direction is the A direction,
Of the permanent magnet and the core, the one disposed on the guide rail side is the first magnetic body, the one disposed on the guide block side is the second magnetic body,
The first magnetic body so that the center of the A direction length of the first magnetic body is shifted in the direction from the guide rail toward the guide block with respect to the center of the A direction length of the second magnetic body. It was placed,
The distance between the center of the length of the second magnetic body in the A direction and the center of the length of the first magnetic body in the A direction is defined as a shift amount x [mm], and the length of the second magnetic body in the A direction is Lm [ mm]
0 <x / Lm ≦ 0.78
A linear motor-driven shaft feed device characterized by being within a range that satisfies the above . 2. The linear motor drive shaft feeding device according to claim 1, wherein the length of the permanent magnet in the A direction is different from the length of the core in the A direction . One of the first magnetic body and the second magnetic body having a short length in the A direction is opposed to the other of the first magnetic body and the second magnetic body having a long length in the A direction. The linear motor drive shaft feeding device according to claim 2, wherein the linear motor driving shaft feeding device is arranged . One of the first magnetic body and the second magnetic body having a short length in the A direction is the core, and the other of the first magnetic body and the second magnetic body having a long length in the A direction is the permanent. The linear motor drive shaft feed device according to claim 2 , wherein the shaft feed device is a magnet . The first magnetic body and the second magnetic body are arranged so that one end face in the A direction of the first magnetic body and one end face in the A direction of the second magnetic body substantially coincide with each other. A linear motor drive shaft feed device according to claim 4 . When the length of the first magnetic body in the A direction is Lp [mm],
1 <Lm / Lp ≦ 1.34
6. The linear motor drive shaft feed device according to claim 5, wherein the shaft feed device is within a range satisfying the above.

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