JP5370697B2 - Linear motor - Google Patents

Abstract

The invention provides a linear motor, which enables the stability and reliability to be improved and the machine body miniaturization to be realized. The linear motor comprises a first shaft, a second shaft parallelly arranged with the first shaft; two connecting parts for connecting the end parts of the first and second shafts; a first frame possessing a first penetrating hole penetrating the first shaft; a second frame possessing a second penetrating hole penetrating the second shaft; a linear coder possessing a scale and a sensor and configured such that the separation direction of the scale and the sensor is generally constant with the direction of a surface comprising the first shaft axis and the second shaft axis. By setting the first and second shafts and the connecting parts as rotors and setting the first and second frames as stators, the linear motor goes forward and back and moves relatively to the axis direction.

Description

  The disclosed embodiment relates to a linear motor.

  Conventionally, a stator in which a plurality of coils wound in a cylindrical shape on the inner diameter side of a metal pipe made of a cylindrical magnetic material are arranged in the axial direction, and a cylindrical shape that is disposed inside the stator via a magnetic gap There has been proposed a cylindrical linear motor provided with a mover in which a plurality of permanent magnets are inserted in the axial direction on the inner diameter side of the shaft (can) (see, for example, Patent Document 1). This linear motor has a linear encoder including a scale (linear scale) provided on a shaft and a sensor (detector) provided on a metal pipe.

International Publication No. 2007/046161 Pamphlet (Figure 8-9)

  In the above-described prior art linear motor, the scale of the linear encoder is provided on the shaft and the sensor is provided on the metal pipe, so that an external force or vibration acts on the shaft to cause a gap between the scale and the sensor. May fluctuate. That is, there is room for improvement in robustness. In addition, the electromagnetic part that generates the thrust of the mover by the coil and the permanent magnet and the encoder part provided with the linear encoder having the scale and the sensor each require a space twice as large as the stroke. In the prior art, since the electromagnetic part and the linear encoder are arranged in series, there has been a problem that the axial dimension of the motor increases and the physique increases.

  An object of the present invention is to provide a linear motor that can be reduced in size while improving robustness.

To solve the above problems, according to one aspect of the present invention includes a first shaft having a predetermined first axis, a second shaft with a predetermined second axis, the said first A linear motor in which the first shaft and the second shaft are arranged in parallel so that an axis and the second axis are different from each other and parallel to each other, and the first shaft is connected to the first axis. A plurality of magnetic poles arranged along, at least two connecting members connecting the end portions of the first shaft and the second shaft, a first through hole through which the first shaft passes, and the second shaft penetrating. A frame having a plurality of armature windings arranged on an inner peripheral surface of the first through hole, an outer peripheral surface of the second shaft, and an inner peripheral surface of the second through hole. Scale provided on either side and cell provided on the other Has a support, a gap direction between the scale and the sensor, the said first shaft of said first axis and said second shaft of the second axis substantially coincides vital the first axis and the plane direction including the A magnetic linear encoder disposed so as to be positioned between the first axis , the second shaft, the connecting member, and the frame. A linear motor that relatively moves forward and backward in the axial direction is used with the other as the stator.

  According to the linear motor of the present invention, the physique can be reduced in size while improving the robustness.

It is a sectional side view showing the whole linear motor composition of one embodiment. It is a cross-sectional view of the linear motor corresponding to the II-II cross section in FIG. It is a sectional side view showing the whole linear motor composition in the modification which arranges a linear encoder in the 1st direction other side of the 2nd shaft. FIG. 4 is a transverse sectional view of the linear motor corresponding to the IV-IV section in FIG. 3. It is a sectional side view showing the whole linear motor composition in the modification which makes the 2nd shaft a hollow structure. It is a cross-sectional view of the linear motor corresponding to the VI-VI cross section in FIG.

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

  1 and 2, a linear motor 1 according to this embodiment is a piston-type linear motor having a movable element having a two-axis structure. The linear motor 1 includes a first frame 2A, a second frame 2B, two connecting members 3, a first shaft SH1, and a second shaft SH2 arranged in parallel so as to be parallel to the first shaft SH1. The linear encoder 10 is provided.

  The first frame 2A is disposed at both ends of the first through-hole 4 through which the first shaft SH1 passes and the first through-hole 4, and the first shaft SH1 is arranged in the axial direction (left-right direction in FIG. 1, front side in FIG. 2). And two first linear motion bearings 5 supported so as to be linearly movable in the back direction). A plurality of armature windings 7 wound in a cylindrical shape with a copper wire or the like are arranged in the axial direction on the inner peripheral surface of the first through hole 4.

  The second frame 2B is configured as a separate body from the first frame 2A, and is connected to the first frame 2A via an appropriate fixing agent. The first frame 2A and the second frame 2B correspond to the frames described in the claims. The first frame 2A and the second frame 2B may be configured integrally, that is, configured as one frame. The second frame 2B is disposed at both ends of the second through hole 8 through which the second shaft SH2 passes and the second through hole 8, and supports the second second shaft SH2 so as to be linearly movable in the axial direction. And a linear motion bearing 9.

  The connecting member 3 is provided on the load side (right side in FIG. 1) and the anti-load side (left side in FIG. 1) of the first frame 2A and the second frame 2B. The end portions of the first shaft SH1 and the second shaft SH2 are fitted into recesses (not shown) provided on the inner sides (sides facing the first frame 2A and the second frame 2B) of the connecting members 3, respectively. Thus, the end portions of the first shaft SH1 and the second shaft SH2 are connected on the load side and the anti-load side of the first frame 2A and the second frame 2B.

  The first shaft SH1 passes through the first through hole 4 of the first frame 2A, and is supported by a first linear bearing 5 provided at both ends of the first through hole 4 so as to be linearly movable in the axial direction. ing. On the first shaft SH1, permanent magnets 6 constituting a plurality of magnetic poles are arranged at a predetermined pitch in the axial direction. The plurality of permanent magnets 6 are opposed to the plurality of armature windings 7 whose magnetic pole surfaces are arranged on the inner peripheral surface of the first through-hole 4 through magnetic gaps, and are arranged with N poles in the axial direction or They are arranged with their directions reversed alternately so that the S poles face each other. That is, in the portion where the permanent magnets 6 are arranged, the N-pole magnetic poles and the S-pole magnetic poles are alternately arranged in the axial direction. In addition, as a member which comprises a magnetic pole, it is not restricted to a permanent magnet, You may use other members (for example, electromagnet etc.).

  The second shaft SH2 passes through the second through hole 8 of the second frame 2B, and is supported by the second linear bearings 9 provided at both ends of the second through hole 8 so as to be linearly movable in the axial direction. ing. The second shaft SH2 has a flat surface on one side (lower side in FIGS. 1 and 2) of the first direction (vertical direction in FIGS. 1 and 2) orthogonal to the axial direction of the outer peripheral surface. It has become. And the linear encoder 10 is arrange | positioned at the 1st direction one side of this 2nd shaft SH2.

  In this example, the linear encoder 10 is a magnetic encoder, and includes a scale 101 provided with a magnetic pattern, a substrate 102, and a sensor 103 that detects a magnetic field generated by the magnetic pattern provided on the scale 101. The scale 101 is provided on the flat surface on the one side in the first direction among the outer peripheral surfaces of the second shaft SH2. The substrate 102 constitutes a part of the inner peripheral surface of the second through hole 8 of the second frame 2B, and is on the other side in the first direction (upper side in FIGS. 1 and 2) of the outer peripheral surface of the first frame 2A. It is provided on the surface. The sensor 103 is provided on the substrate 102 so as to face the scale 101 via the gap G in the first direction. Note that the sensor 103 is provided on the substrate 102 that the sensor 103 forms a part of the inner peripheral surface of the second through hole 8 of the second frame 2B in the first direction of the outer peripheral surface of the first frame 2A. It is equivalent to being provided on the other side surface. The linear encoder 10 has a second direction orthogonal to the axial direction of the sensor 103 among the directions related to the gap G in the first direction between the scale 101 and the sensor 103 (the front and back direction in FIG. 1, FIG. 2). The gap direction A passing through the substantially center of the center (left and right direction) is disposed so as to substantially coincide with the surface direction B including the axis AX1 of the first shaft SH1 and the axis AX2 of the second shaft SH2.

  In the linear motor 1 configured as described above, the first shaft SH1, the second shaft SH2, the connecting member 3 and the like constitute the mover 30, and the first frame 2A and the second frame 2B and the like are the stator 40. Is configured. And in this linear motor 1, the needle | mover 30 and the stator 40 move forward / backward relatively in an axial direction. That is, when the armature winding 7 is energized in the electromagnetic part 60 provided on the first frame 2A side (first shaft SH1 side), the current flowing in the armature winding 7 and the magnetic flux formed by the permanent magnet 6 Due to this interaction, an attractive force and a repulsive force are generated between the armature winding 7 and the magnetic poles of the permanent magnet 6, and this becomes a driving force, and the mover 30 moves forward and backward in the axial direction. Further, when the mover 30 moves, the encoder unit 70 provided on the second frame 2B side (second shaft SH2 side) detects the magnetic field generated by the magnetic pattern provided on the scale 101 by the sensor 103. The position (movement amount) of the mover 30 can be detected.

  As described above, in the linear motor 1 of the present embodiment, the first shaft SH1 and the second shaft SH2 that are arranged in parallel, the two connecting members 3 that connect these end portions, the first frame 2A, The second frame 2B is provided, and the mover 30 and the stator 40 are relatively moved forward and backward in the axial direction. Further, the linear motor 1 of the present embodiment includes a linear encoder 10. The linear encoder 10 includes a scale 101 provided on the outer peripheral surface of the second shaft SH2 and a sensor 103 provided on the inner peripheral surface of the second through hole 8 of the second frame 2B. The gap direction A with respect to the sensor 103 is disposed so as to substantially coincide with the surface direction B including the axis AX1 of the first shaft SH1 and the axis AX2 of the second shaft SH2.

  Thus, by connecting the end portions of the first shaft SH1 and the second shaft SH2 with the connecting member 3, these can be formed into a frame-type structure, and the rigidity of the second shaft SH2 with respect to the surface direction B can be increased. It can be improved. Thereby, since the rigidity of 2nd shaft SH with respect to the said gap direction A can be improved, the fluctuation | variation of the gap G of the scale 101 and the sensor 103 can be suppressed. Therefore, robustness can be improved.

  In the linear motor 1, the electromagnetic unit 60 that generates the thrust of the mover 30 by the armature winding 7 and the permanent magnet 8, and the encoder unit 70 provided with the linear encoder 10 having the scale 101 and the sensor 102 are: Because of its structure, a space twice as long as the stroke is required, but in this embodiment, the electromagnetic unit 60 and the encoder unit 70 are arranged in parallel, so that the linear motor is compared to the case where they are arranged in series. The axial dimension of 1 can be greatly reduced. Furthermore, when these are arranged in series, the encoder section can be configured to be smaller in the radial direction than the electromagnetic section, but these are generally housed in a frame of the same diameter. The physique is unnecessarily enlarged. On the other hand, in this embodiment, since the electromagnetic unit 60 and the encoder unit 70 are arranged in parallel, the first frame 2A and the second frame 2B are configured so that the arrangement space of the encoder unit 70 is minimized. Thus, the size of the linear motor 1 can be reduced.

  Therefore, according to this embodiment, the physique of the linear motor 1 can be reduced in size while improving the robustness.

  In the present embodiment, the following effects can be obtained. That is, in general, an optical type and a magnetic type are mainly used as an encoder of a linear motor. The magnetic encoder has a simple structure, a small number of parts, and a low cost compared to the optical encoder, but has a characteristic that it is weak against gap fluctuation and low in robustness. On the other hand, the optical encoder has excellent position resolution performance and high robustness compared with the magnetic encoder, but is expensive. In this embodiment, since the fluctuation of the gap G between the scale 101 and the sensor 103 can be suppressed, a magnetic encoder is used as the linear encoder 10. Thereby, cost reduction of the linear encoder 10 can be achieved.

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

(1) In the case where the linear encoder is disposed on the other side in the first direction of the second shaft In the above embodiment, the linear encoder 10 is disposed on the one side in the first direction of the second shaft SH2, but this is not restrictive. The linear encoder may be arranged on the other side in the first direction of the second shaft.

  3 and 4, the second shaft SH2 'of the linear motor 1' of the present modification is orthogonal to the axial direction (the left-right direction in FIG. 3, the front to back direction in FIG. 4) of the outer peripheral surface. The surface on the other side (upper side in FIGS. 3 and 4) in one direction (up and down direction in FIGS. 3 and 4) is a flat surface. A linear encoder 10 'is arranged on the other side in the first direction of the second shaft SH2'.

  The scale 101 ′ of the linear encoder 10 ′ is provided on the flat surface on the other side in the first direction of the outer peripheral surface of the second shaft SH2 ′. The substrate 102 'is provided on the surface on the other side in the first direction among the inner peripheral surfaces of the second through holes 8 of the second frame 2B. The sensor 103 'is provided on the substrate 102' so as to face the scale 101 'via the gap G' in the first direction. The provision of the sensor 103 'on the substrate 102' is equivalent to the provision of the sensor 103 'on the other surface in the first direction of the inner peripheral surface of the second through hole 8 of the second frame 2B. is there. The linear encoder 10 'is orthogonal to the axial direction of the sensor 103' in the direction related to the gap G 'in the first direction between the scale 101' and the sensor 103 ', like the linear encoder 10 in the above embodiment. The gap direction A ′ passing through the approximate center of the second direction (the front and back direction in FIG. 3 and the left and right direction in FIG. 4) includes the axis AX1 of the first shaft SH1 and the axis AX2 ′ of the second shaft SH2 ′. They are arranged so as to substantially coincide with the surface direction B ′.

  In the linear motor 1 'of the present modification, the first shaft SH1, the second shaft SH2', the connection member 3 and the like described above constitute a mover 30 ', and the first frame 2A and the second frame described above. 2B and the like constitute the stator 40. In this linear motor 1 ′, the mover 30 ′ and the stator 40 relatively move forward and backward in the axial direction.

  The other configuration of the linear motor 1 ′ is the same as that of the linear motor 1 of the above embodiment.

  According to this modified example described above, the physique of the linear motor 1 ′ can be reduced in size while improving the robustness as in the above embodiment.

(2) Case where the second shaft has a hollow structure In FIGS. 5 and 6, the second shaft SH <b> 2 ″ of the linear motor 1 ″ of this modification has a hollow structure and has a hollow portion 12. As with the second shaft SH2 in the above-described embodiment, the second shaft SH2 ″ has a first direction (right and left direction in FIG. 5 and the front and back direction in FIG. 6) perpendicular to the axial direction of the outer peripheral surface thereof. The surface on one side (the lower side in FIGS. 5 and 5) in FIG. 5 and FIG. 5 is a flat surface. The linear encoder 10 is arranged.

  The linear encoder 10 has a second direction orthogonal to the axial direction of the sensor 103 among the directions related to the gap G in the first direction between the scale 101 and the sensor 103 (see FIG. 5). A gap direction A ″ passing through the approximate center of the front side of the middle sheet surface (left and right direction in FIG. 5) is a plane direction B ″ including the axis AX1 of the first shaft SH1 and the axis AX2 ″ of the second shaft SH2 ″. It arrange | positions so that it may correspond substantially.

  Further, the two connecting members 3 ″ are the same as the two connecting members 3 in the above-described embodiment, on the load side (right side in FIG. 5) and the anti-load side (FIG. 6) of the first frame 2A and the second frame 2B. These connecting members 3 ″ are provided in the recesses (not shown) provided on the inner sides of the first shafts SH1 and the end portions of the first shaft SH1 are provided on the inner sides. By inserting the second shaft SH2 ″ through the through holes (not shown), the ends of the first shaft SH1 and the second shaft SH2 ″ on the load side and the non-load side of the first frame 2A and the second frame 2B. The parts are connected.

  In the linear motor 1 ″ of this modification, the first shaft SH1, the second shaft SH2 ″, the connecting member 3 ″ and the like constitute a mover 30 ″, and the first frame 2A and the second frame 2B and the like are stators. 40. In this linear motor 1 ″, the mover 30 ″ and the stator 40 move relatively back and forth in the axial direction.

  Further, on the axis AX2 ″ of the second shaft SH2 ″, more specifically, at the load side end portion of the second shaft SH2 ″ (hereinafter referred to as “load side tip portion of the second shaft SH2 ″” as appropriate) An electric gripper 14 is attached as a jig for handling equipment / parts. The electric gripper 14 has two claws 141, and is a jig that can grip devices, parts, and the like with the two claws 141. The electric gripper 14 is moved along with the movement of the movable element 30 ″. A wiring 13 for connecting one end side to the electric gripper 14 and supplying electric power to the electric gripper 14 is connected to the second shaft SH2. In this example, two are inserted and disposed in the hollow portion 12 inside. Therefore, electric power can be supplied to the electric gripper 14 via the wiring 13.

  The other configuration of the linear motor 1 ″ is the same as that of the linear motor 1 of the above-described embodiment.

  According to the present modification described above, the physique of the linear motor 1 ″ can be reduced in size while improving the robustness, as in the above-described embodiment. In the present modification, the second shaft SH2 is reduced. ″ Is a hollow structure, and the first shaft SH1, the second shaft SH2 ″, the connecting member 3 ″ and the like are the mover 30 ″. The load of the second shaft SH2 ″ for handling devices and parts, etc. A wiring 13 for supplying electric power to the electric gripper 14 provided at the side tip portion is disposed through the hollow portion 12 inside the second shaft SH2 ″. Since it is not necessary to connect to the tip of the two shafts SH2 ″ from the lateral direction, it is possible to reduce the driving resistance acting on the movable element 30 ″ due to the tension of the wiring 13. Also, the flow path direction is changed. Since the order of the members such as is also unnecessary, it is possible to reduce the weight of the mover 30 ". Therefore, the tact time can be improved. Further, since the member for changing the flow path direction is not necessary, a guide member for preventing the axial movement of the mover 30 ″ is not necessary, so that the weight of the entire linear motor 1 ″ is further reduced. In addition, the size can be reduced. Further, since the wiring 13 can be disposed in the second shaft SH2 ″, space can be saved as compared with the case where the wiring is routed outside the linear motor.

  The jig attached to the load side tip of the second shaft SH2 ″ is not limited to the electric gripper 14. For example, another jig may be attached to the load side tip of the second shaft SH2 ″. When a pick capable of vacuum-sucking equipment / components as a jig is attached, a fluid tube for sucking a fluid such as air is connected to the pick and the second shaft SH2 is connected to the pick at one end side. The hollow portion 12 "can be inserted and disposed. In this case, it is not necessary to connect the fluid tube to the tip of the second shaft SH2" from the lateral direction. The driving resistance acting on the mover 30 ″ can be reduced. Further, since the fluid tube can be disposed in the second shaft SH2 ″, the fluid tube is disposed outside the linear motor. It is possible to achieve a space saving compared to the case where routed Oite.

(3) Others In the above, the scale 101 or the like such as the linear encoder 10 is provided on the outer peripheral surface of the second shaft SH2 or the like, and the sensor 103 or the like is provided on the inner peripheral surface of the second through hole 8 of the second frame 2B. However, on the contrary, the scale may be provided on the inner peripheral surface of the second through hole 8 of the second frame 2B, and the sensor may be provided on the outer peripheral surface of the second shaft SH2.

  In the above description, the two connecting members 3 and the like for connecting the first shaft SH1 and the second shaft SH2 and the like are provided. However, the present invention is not limited to this, and a configuration in which three or more connecting members are provided may be used.

  Moreover, although the case where the linear encoder 10 etc. was a magnetic encoder was demonstrated as an example above, it is not restricted to this, It can apply also when the linear encoder is an optical encoder.

  Further, the case where the first shaft SH1, the second shaft SH2, etc. and the connecting member 3 etc. are movers and the first frame 2A, the second frame 2B etc. are stators has been described as an example. The present invention is also applicable to the case where the first shaft, the second shaft, and the connecting member are a stator and the frame is a mover.

  In addition to those already described above, the methods according to the above-described embodiments and modifications may be used in appropriate combination.

  In addition, although not illustrated one by one, the above-mentioned embodiment and each modification are implemented with various modifications within a range not departing from the gist thereof.

1, 1 ', 1 "linear motor 2A first frame 2B second frame 3, 3" connecting member 4 first through hole 6 permanent magnet 7 armature winding 8 second through hole 10, 10' linear encoder 30, 30 ', 30 "Movable element 40 Stator 101, 101' Scale 103, 103 'Sensor A, A', A" Gap direction AX1 axis (axis of first shaft)
AX2, AX2 ', AX2 "axis (axis of second shaft)
B, B ', B "surface direction SH1 first shaft SH2, SH2', SH2" second shaft

Claims (2)

A first shaft having a predetermined first axis ;
A second shaft having a predetermined second axis ;
Have
A linear motor in which the first shaft and the second shaft are arranged in parallel so that the first axis and the second axis are different from each other and parallel to each other;
A plurality of magnetic poles arranged along the first axis on the first shaft;
At least two connecting members that connect ends of the first shaft and the second shaft;
A frame having a first through-hole through which the first shaft passes and a second through-hole through which the second shaft passes, and a plurality of armature windings arranged on an inner peripheral surface of the first through-hole;
A scale provided on one of an outer peripheral surface of the second shaft and an inner peripheral surface of the second through-hole and a sensor provided on the other; and a gap direction between the scale and the sensor is 1 linear magnetic disposed so as to be positioned between the plane direction including the second axis of the first axis and the second shaft of the shaft substantially coincides vital said first axis and said second axis An encoder, and
One of the first shaft, the second shaft, the connecting member, and the frame is used as a mover and the other as a stator, and the linear motor moves relatively back and forth in the axial direction. . The linear motor according to claim 1, wherein the second shaft has a hollow structure .

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