JP2005287290A - Linear motor actuator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a linear motor actuator of which the entire is miniaturized while the heat is hard to flow into the slider of a linear guiding device from a coil member, being manufactured at a low cost. <P>SOLUTION: The actuator comprises a track rail 3, a slider 4 reciprocable along the track rail 3, a magnet rod 6a that is supported by both ends to be parallel to the track rail 3, directly above the slider 4, a coil member 6b which is loosely fitted around the magnet rod 6a, and a guide table 5 which is positioned directly above the magnet rod 6a and reciprocates along with the coil member 6b and the slider 4. The guide table 5 is fixed to the slider 4 through support members 9a and 9b. The housing space for the coil member 6b is formed between the guide table 5 and the slider 4. The coil member 6b is held in the housing space without contacting the slider 4. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a linear motor actuator in which a coil member as a mover moves relative to a magnet rod as a stator in which N-pole magnetic poles and S-pole magnetic poles are alternately arranged.

JP 2002-136097 A JP-A-11-150973

  Linear motor actuators are frequently used for the purpose of linearly moving articles, members, and the like in FA devices such as an XY table and an article transport apparatus. This type of linear motor actuator normally provides a guide table on which a movable body such as an article to be transported is mounted, a linear guide device that allows the guide table to freely reciprocate linearly, and applies thrust to the guide table. It consists of a linear motor and a linear encoder that detects the position of the guide table. By controlling the linear motor according to the detected value of the linear encoder, an arbitrary amount of movement can be made to the guide table with high accuracy. (Japanese Patent Laid-Open No. 2002-136097, etc.).

  As the linear motor, a field magnet as a stator in which N-pole magnetic poles and S-pole magnetic poles are alternately arranged is arranged on a base plate, and on the lower surface side of a guide table supported by the linear guide device. 2. Description of the Related Art A coil member is provided as a mover, and these field magnets and coil members are opposed to each other with a slight gap.

  However, when the field magnet is arranged on the base plate as described above, in order to make the coil member and the field magnet face each other, it is necessary to provide the guide table so as to straddle the field magnet. It is necessary to provide a pair of linear guide devices on both sides of the field magnet to support the linear reciprocating motion of the guide table, and the structure of the actuator itself tends to increase in size.

  On the other hand, as another type of linear motor, a so-called shaft type is known (Japanese Patent Application Laid-Open No. 11-150973). This shaft type linear motor is formed in a rod shape, and N poles and S poles are repeatedly arranged at a predetermined pitch along the axial direction, and a magnet rod as a stator whose both ends are supported on a base plate, It is composed of a coil member that is loosely fitted around the magnet rod through a slight gap. By energizing the coil member, the coil member moves around the magnet rod along the axial direction. It is configured.

  In this shaft type linear motor, a coil member surrounds the magnet rod, so that a strong thrust can be exerted. When an actuator is configured using such a linear motor, the size is reduced. However, a large thrust can be applied to the guide table. A linear guide device that supports the reciprocating motion of the guide table is usually composed of a track rail disposed on the base plate and a slider that moves along the track rail. Then, it is possible to adopt a so-called built-up structure in which the coil member is fixed to a slider and a guide table is further fixed on the coil member, like the linear motor actuator disclosed in Japanese Patent Laid-Open No. 2002-136097. Compared to the type that uses a biaxial linear guide device, the actuator itself has a characteristic that it is easy to miniaturize.

  However, since the coil members constituting the linear motor generate significant heat when energized, if the coil members are directly fixed to the slider using a built-up structure, the heat generated by the coil members flows into the slider. There is a concern that the movement accuracy and life of the linear guide device may be adversely affected. In order to prevent heat conduction from the coil member to the slider, a method such as interposing a heat insulating member between them can be considered, but the thrust generated between the coil member and the magnet rod is transmitted to the slider. From this point of view, the coil member needs to be integrated with the slider with high rigidity, and the heat insulating member is also required to have high rigidity, so the structural and material restrictions of the heat insulating member are large, This leads to an increase in manufacturing costs.

  The present invention has been made in view of such problems, and the object of the present invention is to prevent heat from flowing from the coil member to the slider of the linear guide device while reducing the size of the entire actuator. In addition, an object is to provide a linear motor actuator that can be manufactured at low cost.

  That is, the linear motor actuator of the present invention includes a base plate, a track rail disposed on the base plate, a slider that can freely reciprocate along the track rail, and a parallel to the track rail immediately above the slider. A magnet rod as a stator that is supported at both ends and arranged with a large number of magnetic poles at a predetermined pitch along the axial direction, and a mover that is fixed to the slider and is loosely fitted around the magnet rod. And a guide table that is positioned immediately above the magnet rod and reciprocates with the coil member and the slider, the guide table being fixed to the slider via a support member, A space for accommodating the coil member is formed between the slider and the slider. The coil member is what is held in the housing space without contacting the slider.

  According to such a linear motor actuator of the present invention, the guide table is fixed to the slider via the support member, so that an accommodation space for the coil member constituting the linear motor is formed between the slider and the guide table. The While the coil member is held in the accommodation space, it is kept in non-contact with the slider. As a method of holding the coil member in the accommodation space, the coil member may be fixed to the guide table, or may be fixed to the support member, but at least between the slider and the coil member. A gap is formed between them, and both are kept in a non-contact state. As a result, the heat generated by energizing the coil member can be prevented from flowing directly into the slider, and the moving accuracy of the slider relative to the track rail and the life of the slider can be prevented from being adversely affected. Become.

  In addition, heat can be prevented from flowing from the coil member to the slider without using a heat insulating member, and this can be achieved with a simple structure. it can.

  Furthermore, since a gap is formed between the slider and the coil member, it is possible to install a cooler such as a water jacket in the gap, and since no load acts on the cooler, mechanical Various types can be adopted without worrying about strength.

  Since the heat generated in the coil member can be prevented from being transmitted to the slider in this way, the coil member can be energized without worrying about the heat generated by the coil member, and the energization current value can be increased. Thus, a large thrust can be generated in the linear motor.

  Hereinafter, the linear motor actuator of the present invention will be described in detail with reference to the accompanying drawings.

  FIG. 1 is a schematic side view showing an embodiment of the linear motor actuator of the present invention. The linear motor actuator 1 includes a long base plate 2, a single track rail 3 disposed on the base plate 2 along the longitudinal direction thereof, and a slider 4 capable of linear reciprocation along the track rail. And a guide table 5 that is fixed to the slider 4 and has a mounting surface for a movable body, and a linear motor 6 that applies thrust to the guide table 5, and is mounted on the guide table 5. The movable body can be reciprocated along the longitudinal direction of the base plate 2 and stopped at an arbitrary position.

  FIG. 2 is a perspective view showing the linear motor 6. The linear motor 6 includes a magnet rod 6a as a stator formed in a long cylindrical shape, and a coil member 6b as a mover loosely fitted around the magnet rod 6a with a slight gap. Has been. A plurality of permanent magnets 60 are arranged along the axial direction on the magnet rod 6a, and the outer peripheral surface is processed smoothly. As shown in FIG. 3, each permanent magnet 60 has an N pole and an S pole, and adjacent permanent magnets 60 are arranged with their directions alternately reversed so that the N poles or the S poles face each other. Has been. As a result, a magnetizing portion for driving in which N pole magnetic poles and S pole magnetic poles are alternately arranged along the longitudinal direction of the magnet rod 6a is formed, and this is a field magnet.

  As shown in FIG. 1, both ends of the magnet rod 6 a are fixed to a pair of end plates 20 and 21, and the pair of end plates 20 and 21 face each other at both ends in the longitudinal direction of the base plate 2. To be fixed. That is, the magnet rod 6a is fixed on the base plate 2 like a support beam at both ends.

  On the other hand, the coil member 6b is configured by housing a cylindrical excitation coil 62 in a housing 61 formed entirely in a quadrangular prism shape. The housing 61 is formed of aluminum having excellent thermal conductivity, and a plurality of heat radiating fins 63 are erected on the surface thereof in parallel with the longitudinal direction of the magnet rod. In addition, the heat generated by the exciting coil 62 can be efficiently transmitted to the housing 61, and can be radiated into the surrounding atmosphere, thereby effectively cooling the exciting coil 62 itself.

  3 and 4 show the operating principle of the linear motor 6. FIG. The exciting coil 62 has a coil group including three coils of U, V, and W phases. The excitation coil 62 of any phase is ring-shaped and faces the outer peripheral surface of the magnet rod 6a with a slight gap. In addition, the arrangement pitch of the excitation coils 62 of each phase is set shorter than the arrangement pitch of the permanent magnets 60. A magnetic flux 64 is formed on the macnet rod 6a from the magnetic pole of the S pole toward the magnetic pole of the N pole, and a magnetic pole sensor (not shown) for detecting the magnetic flux density is built in the coil member 6b. Therefore, the positional relationship of each magnetic pole (N pole and S pole) of the magnet rod with respect to the exciting coil is grasped from the detection signal output from the magnetic pole sensor. The controller that controls the energization of the exciting coil receives the detection signal of the magnetic pole sensor, calculates the optimum current according to the positional relationship between the exciting coil and each magnetic pole of the magnet rod, and applies it to each exciting coil. Energize. As a result, an attractive force and a repulsive force are generated between the exciting coil 62 and each magnetic pole of the permanent magnet 60 due to the interaction between the current flowing in each exciting coil 62 and the magnetic flux 64 formed by the permanent magnet 60. The member 6b is propelled in the axial direction of the magnet rod 6a.

  5 and 6 are a side view and a front sectional view showing the assembled state of the track rail 3, slider 4, guide table 5 and coil member 6b with respect to the base plate 2, and FIG. 6 is a sectional view taken along the line VI-VI in FIG. The figure is shown.

  The track rail 3 and the slider 4 constitute a linear guide device that freely reciprocates the guide table 5 on the base plate 2. The track rail 3 has a cross section perpendicular to the longitudinal direction formed in a substantially rectangular shape, is formed to have a length substantially the same as the entire length of the base plate 2, and is disposed in parallel to the longitudinal direction of the base plate 2. ing. The track rail 3 is formed with a plurality of ball rolling grooves along the longitudinal direction on both side surfaces and the upper surface thereof.

  On the other hand, the slider 4 moving along the track rail 3 is formed in a saddle shape with a guide groove in which the upper portion of the track rail 3 is loosely fitted through a slight gap, and a large number of balls circulate. A ball infinite circulation path is provided, and the ball can move continuously along the track rail 3 by rolling the ball rolling groove of the track rail 3. The slider 4 is loaded with a load that acts in a direction perpendicular to the longitudinal direction of the track rail 3, that is, a direction perpendicular to the moving direction of the slider 4, and the magnet rod 6 a is applied to the coil member 6 b of the linear motor 6. It prevents the load other than the axial direction from acting.

  In addition, as a combination of the track rail 3 and the slider 4, a commercially available linear guide device (for example, LM guide manufactured by THK Co., Ltd.) can be used, and is commercially available according to the magnitude and direction of the load acting on the guide table 5. Any linear guide device can be selected from the various types of linear guide devices.

  A fixed reference groove 22 for accommodating the bottom of the track rail 3 is formed in the base plate 2 along the longitudinal direction, and the side surface of the track rail 3 is in contact with the side surface of the fixed reference groove 22. These are fixed to the base plate 2 by fixing bolts 21. The fixed reference groove 22 is formed in parallel with the axial direction of the magnet rod 6a supported at both ends by the end plates 20 and 21, thereby ensuring the parallelism of the track rail 3 and the magnet rod 6a. Yes. As shown in FIG. 6, a side wall 24 is erected along the longitudinal direction at one end in the width direction of the base plate 2, and a magnet scale 40 constituting a linear encoder is provided on the outer surface of the side wall 24. 3 is fixed over the entire region in the moving direction.

  Further, a saddle plate 8 for supporting the guide table 5 is fixed to the slider 4. The saddle plate 8 is fixed to the upper mounting surface of the slider 4 by mounting bolts 80. As shown in FIG. 6, a flange portion 81 for fixing the read head 41 of the linear encoder protrudes from one end in the width direction of the saddle plate 8, and this flange portion 81 is provided on the side wall 24 of the base plate 2. It is provided to get over. The read head 41 of the linear encoder is fixed so as to be suspended from the flange portion 81, and faces the magnet scale 40 fixed to the side wall 24 of the base plate 2. Thereby, when the slider 4 moves along the track rail 3, the read head 41 of the linear encoder moves along the magnet scale 40, and the amount of movement of the slider 4 relative to the base plate 2 is grasped from the output signal of the read head 41. Be able to.

  As the linear encoder, it is possible to select and use a linear encoder having a resolution according to the application of the linear motor actuator, a type that detects a change in magnetism in a magnet scale, or a pattern formed on the scale surface. It is possible to select arbitrarily such as a type of optically reading.

As shown in FIG. 5, a pair of sagittal plates 9a and 9b are erected at the front and rear ends of the saddle plate 8 in the moving direction, and the guide table 5 is fixed to the two support plates 9a and 9b. ing. Each support plate 9a, 9b is fixed to the saddle plate 8 and the guide table 5 by a fixing bolt 90, and an open hole 91 through which the magnet rod 6a passes is formed at the center thereof as shown in FIG. .
There is a space between the saddle plate 8 and the guide table 5 sandwiched from the front and the back by the support plates 9 a and 9 b, and this space is a housing space 92 for the coil member 6 b of the linear motor 6.

  The saddle plate 8 can also be formed integrally with the slider 4, and if the support plate 8 can be erected directly before and after the slider 4, it is not necessary to provide it.

  The pair of support plates 9a and 9b corresponds to the support member of the present invention, and the support member forms an accommodation space 92 for the coil member 6b between the guide table 5 and the slider 4. For example, it is not necessarily required to be configured as two support plates. For example, a bracket having a substantially U-shaped cross section that couples the guide table 5 and the slider 4 in a non-contact manner may be used.

  The coil member 6b is not directly fixed to the saddle plate 8 and the support plates 9a and 9b, but is fixed to the lower surface of the guide table 5 by a suspension bolt 50 penetrating the guide table 5, and in this state, the magnet rod 6a. Are loosely fitted. Further, in order to prevent heat generated by energizing the coil member 6b from flowing into the guide table 5, a heat insulating member 52 is interposed between the guide table 5 and the coil member 6b, and further suspended. A heat insulating member 53 is also interposed between the bolt 50 and the guide table 5.

  Thus, the coil member 6b is located in the accommodation space 92 in a state of being suspended from the guide table 5, and the saddle plate 8 and the support plates 9a and 98b are kept in a non-contact state. That is, a space is formed between the coil member 6b and the saddle plate 8, and between the coil member 6b and the support plates 9a and 9b.

  In this linear motor actuator configured as described above, an energizing force and a repulsive force are generated between the exciting coil 62 and each magnetic pole 60 of the magnet rod 6a by energizing the exciting coil 62 of the coil member 6b. The guide table 5 fixed to the coil member 6b is propelled in the axial direction of the magnet rod 6a. The energization of the coil member 6b to the exciting coil 62 is controlled in accordance with the detection signal of the linear encoder, so that the guide table 5 can be stopped at a predetermined position on the base freight 2.

  In such a linear motor actuator 1, when the guide table 5 is continuously reciprocated, the exciting coil 62 generates heat when energized, and the heat energy flows into the peripheral member through the housing 61 of the coil member 6b. It will be. However, in the linear motor actuator 1 of this embodiment, the housing 61 of the coil member 6 b is suspended and fixed from the guide table 5, and the coil member 6 b is fixed to the saddle plate 8 and the sahor plate 9 a fixed to the slider 4. 9b, there is an air layer between the coil member 6b and the saddle plate 8 and support plates 9a, 9b. For this reason, it is possible to effectively prevent the heat energy generated in the coil member 6b from flowing into the slider 4 and to prevent the temperature of the slider 4 from rising during operation. Accordingly, it is possible to prevent the movement accuracy of the slider 4 with respect to the track rail 3 from being deteriorated and the lubricant such as grease held on the slider 4 from being oxidized at an early stage. It is also possible to prevent the life of the linear guide device composed of 4 from being shortened.

  The accommodation space 92 of the coil member 6b is sandwiched between the support plates 9a and 9b just before and after that, but the left and right in the moving direction of the coil member 6b are open to the outside atmosphere, and the housing 61 of the coil member 6b Since the radiating fins 62 that are erected face the open portion, the radiating fins are easily cooled by air. This also effectively prevents the heat energy generated in the coil member 6b from being transmitted to the slider 4.

  Furthermore, the area of the open hole 91 formed in the support plates 9a and 9b is significantly larger than the cross-sectional area of the magnet rod 6a penetrating the support plate 9a, 9b, and between the outer peripheral surface of the magnet rod and the inner peripheral surface of the open hole. A sufficiently large space is provided. For this reason, when the guide table 5, the support plates 9a and 9b, the saddle plate 8 and the coil member 6b are integrated with the slider 4 and moved along the track rail 3, the support plate 9a (or 9b) located on the front side in the moving direction is used. The air flows into the housing space 92 of the coil member 6b from the open hole 91 of the support member 9b (or 9a) located outside the housing space 92. Will be discharged. This also facilitates air cooling of the housing 61 of the coil member 6b. In particular, the housing 61 is provided with radiating fins 63 erected along the longitudinal direction of the magnet rod 6a, that is, the moving direction of the coil member 6b. This matches the standing direction of 63, and the flow of air around the radiating fin 63 is further promoted. Therefore, the open holes 91 of the support plates 9a and 9b further promote the cooling of the coil member 6b.

  Furthermore, in this embodiment, nothing is arranged between the coil member 6b and the saddle plate 8, and it is used as it is as a space for heat insulation. However, from the viewpoint of actively cooling the coil member 6b. A cooler such as a water jacket may be provided between the coil member 6b and the saddle plate 8. In that case, since the coil member 6b is suspended and fixed from the guide table 5, the cooler is not particularly required to have mechanical strength as long as it is in contact with the coil member 6b. Can be easily performed. Therefore, when used for an application in which a large thrust is required for the linear motor 6, that is, when used for an application in which the amount of heat generated by the coil member 6b is considered to be large, the degree of freedom in design can be increased. It becomes possible to manufacture at a cost.

It is a side view which shows the outline of the Example of the linear motor actuator of this invention. It is a perspective view which shows the linear motor which concerns on an Example. It is a side view which shows the operation principle of the linear motor which concerns on an Example. It is a front view which shows the operation principle of the linear motor which concerns on an Example. It is a side surface enlarged view which shows the waist | hip | lumbar part of the linear motor actuator which concerns on an Example. FIG. 6 is a sectional view taken along line VI-VI in FIG. 5.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Linear motor actuator, 2 ... Base plate, 3 ... Track rail, 4 ... Slider, 5 ... Guide table, 6 ... Linear motor, 6a ... Magnet rod, 6b ... Coil member, 9a, 9b ... Support plate, 92 ... Housing space

Claims (6)

A base plate, a track rail disposed on the base plate, a slider capable of reciprocating freely along the track rail, and supported at both ends in parallel with the track rail immediately above the slider, and in the axial direction A magnet rod as a stator in which a large number of magnetic poles are arranged at a predetermined pitch along the coil, a coil member as a mover fixed to the slider and loosely fitted around the magnet rod, and directly above the magnet rod A linear motor actuator that is located at the same time and is configured to reciprocate with the coil member and the slider,
The guide table is fixed to the slider via a support member, and an accommodation space for the coil member is formed between the guide table and the slider, and the coil member is not in contact with the slider. A linear motor actuator, wherein the linear motor actuator is held in a storage space. The linear motor actuator according to claim 1, wherein the coil member is held on a lower surface side of the guide table. The linear motor actuator according to claim 2, wherein the coil member is not in contact with the support member. 2. The linear motor actuator according to claim 1, wherein the support member includes a pair of support plates erected on the slider so as to sandwich an accommodation space for the coil member, and the accommodation space is open to an external atmosphere. . The pair of support plates are erected so as to sandwich the accommodation space at both front and rear ends in the moving direction of the slider, and the support plate is provided with an open hole through which the magnet rod passes. The linear motor actuator described. The linear motor actuator according to claim 5, wherein the coil member is formed with a radiation fin corresponding to an open portion of the accommodation space.