JP2003324888A - Linear motor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a linear motor having a structure in which thermal expansion is absorbed. <P>SOLUTION: A rail 5 is fixed at both ends of a mover 4 in the direction of the width thereof the mover 4 of which is linearly moved relative to a stator 3 fixed on an enclosure (frame 1 and cover 2). Blocks 6 which guide the rails 5 are supported on the frame 1. At least either of the blocks 6 is set movable in the direction of the width of the mover 4. The blocks 6 are supported on positioning pins 12 for positioning and protruded portions 13a and 13b formed in the vertical direction, and provided with preload by disc springs 14. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a linear motor.

[0002]

2. Description of the Related Art A linear motor is an electric motor that moves linearly, and moves a mover provided on a plate-shaped stator by a magnetic force in a direction along a coil in the stator. Some linear motors move due to magnetic levitation without the mover being restricted by guides, but generally, the mover is restricted by a guide such as a slide guide and moves along the guides. There are many.

The slide guide is composed of a rail having a plurality of grooves and a block in which a plurality of balls (rolling elements) are arranged at positions corresponding to the grooves of the rail, and the balls roll in the grooves of the rail. Therefore, the block moves linearly on the rail. In the linear motor, by supporting the mover using the slide guide, it can be easily applied to an apparatus or the like that requires linear motion.

Usually, the rail of the slide guide is firmly fixed to the frame on the fixed side with bolts, and the block of the slide guide is also firmly fixed to the pedestal on the movable side with bolts. It is necessary for the frame and the pedestal on the movable side to ensure rigidity that is commensurate with the weight and acceleration of the mover. Especially, since the load on the mover side is concentrated on the inner surface of the groove of the slide guide rail and on the ball holding surface of the ball and block, the radial load applied perpendicularly to the movement direction of the slide guide should be taken into consideration. Is selected and arranged.

FIG. 5 is a sectional view of a conventional fully closed linear motor. The side surface perpendicular to the traveling direction of the mover is shown so that the internal structure of the fully closed linear motor can be seen.

As shown in FIG. 5, the fully-closed linear motor has a flat plate-shaped frame 31, a cover 32 fixed to the frame 31 and having a U-shaped cross section for covering the entire linear motor, and a fixed side. A stator 33 disposed on the inner surfaces of the frame 31 and the cover 32 so as to face each other;
A mover 34 provided for the upper and lower stators 33 and moving between the stators 33, and two slide guides arranged between the lower surface of the side of the movable element 34 and the inner surface of the frame 31. And 37.

The stator 33 has a coil 3 for generating a magnetic field.
8 are arranged at regular intervals in the longitudinal direction, and a voltage is supplied to each coil 38 from a power supply unit 39. A plurality of permanent magnets 40 are arranged on the upper and lower surfaces of the mover 34 at regular intervals in the longitudinal direction.

The slide guide 37 is arranged on the lower surface side of the side of the mover 34 and supports the mover 34.
6 and the block 36 so that they can run, and the frame 31
The rail 35 is fixed on the inner surface of the.

In the fully closed linear motor, the mover 34 moves in the traveling direction of the slide guide 37 due to the interaction between the magnetic field formed on the stator 33 side by each coil 38 and the magnetic field of the permanent magnet 40 of the mover 34. Can be moved. In particular, since the stator 33 is arranged above and below the mover 34 in the fully-closed linear motor, the magnetic field on the side of the stator 33 acting on the mover 34 can be applied from both upper and lower sides.
It is possible to give a strong thrust to.

[0010]

Usually, inside a linear motor, heat is generated due to losses such as iron loss, copper loss, mechanical loss due to sliding, etc., and the temperature of each component rises. Particularly, in the fully closed linear motor, it is not easy to cool the inside, so that there is a possibility that a problem due to heat generation may occur.

Specifically, the frame 31 that contacts the outside air side
Also, the stator 33 provided in the cover 32 and the mover 34 provided therein have a difference in cooling capacity, and thus a difference in temperature rise. The difference in temperature rise is
The difference in the amount of thermal expansion, that is, the rail 35 of the slide guide 37
Is a difference between the thermal expansion on the side of the frame 31 to which is fixed and the thermal expansion 20 on the side of the mover 34 to which the block 36 of the slide guide 37 is fixed, and a strong force acts on the slide guide 37. In particular, when the arrangement of the slide guide 37 as shown in FIG. 5 is used, the thermal expansion 20 of the mover 34 exerts a force in the horizontal direction with respect to the movement direction of the slide guide 37. This causes an abnormal temperature rise of the slide guide 37, early peeling, and burnout.

The slide guides currently on the market have basically only one degree of freedom in the sliding traveling direction, and there is no type that can absorb the difference in thermal expansion. Therefore, it is difficult for the slide guide itself to absorb the difference in thermal expansion. It is possible to absorb the difference in thermal expansion in the gap (backlash) inside the slide guide, but since the gap inside the slide guide is an order of magnitude smaller than the difference in thermal expansion, the difference in thermal expansion is only within the gap inside. In order to absorb the heat, it is necessary to extremely suppress the temperature rise of the components of the linear motor, a cooling mechanism is required, and the overall size of the linear motor becomes large. It is also possible to absorb the difference in thermal expansion by increasing the gap inside the slide guide, but the gap inside the slide guide causes vibration and catching of the mover, and therefore cannot be increased unnecessarily. In particular, when the mover is moved at a high speed, the state in which the gap is slightly negative (preload state) is the best in terms of life and vibration.

The present invention has been made in view of the above problems,
An object is to provide a linear motor having a structure that absorbs thermal expansion.

[0014]

A linear motor according to the present invention for solving the above-mentioned problems fixes rails on both ends in the width direction of a mover which is linearly moved with respect to a stator fixed to a housing. A block that guides the rail is supported by the housing, and at least one of the blocks is movable in the width direction of the mover.

The linear motor according to the present invention for solving the above-mentioned problems is characterized in that the housing is provided with positioning means for positioning the block.

The linear motor according to the present invention for solving the above-mentioned problems is characterized in that the rails and the blocks are arranged so as to face each other.

The linear motor according to the present invention for solving the above-mentioned problems is characterized in that a preload applying means for applying a preload to the block is provided.

The linear motor according to the present invention for solving the above-mentioned problems is characterized in that the preload applying means is a spring or an elastic body.

The linear motor according to the present invention for solving the above-mentioned problems is characterized in that the housing is provided with a support means for supporting the block from the vertical direction.

[0020]

1 is a sectional view of a fully enclosed linear motor showing an example of an embodiment according to the present invention. The side surface perpendicular to the traveling direction of the mover is shown so that the internal structure of the fully closed linear motor can be seen.

As shown in FIG. 1, the fully-closed linear motor includes a frame 1 having a U-shaped cross section, a cover 2 fixed to the upper portion of the frame 1 and covering the entire linear motor from the upper surface, and a frame 1. And the stator 3 disposed on the inner surface of the cover 2 so as to face each other, and the upper and lower stators 3.
And a mover 4 that is provided for and moves between the stators 3,
Between the both ends of the mover 4 and the inner surface of the frame 1,
It has slide guides 7a and 7b arranged along the traveling direction of the mover 4. In the fully-closed linear motor, the frame 1 and the cover 2 form a housing, but the structure and shape of the housing are not necessarily limited to those described above.

The stator 3 has a coil 8 for generating a magnetic field.
Are arranged at regular intervals in the longitudinal direction, and a voltage is supplied to each coil 8 from a power supply unit 9. or,
A plurality of permanent magnets 10 are arranged on the upper and lower surfaces of the mover 4 at regular intervals in the longitudinal direction.

The slide guides 7a and 7b are provided at both ends of the mover 4 so as to face each other. One slide guide 7a includes a block 6 fixed to the inner surface of the frame 1 by a bolt 11 and a rail 5 fixed to a side end portion of the mover 4 in the width direction (direction orthogonal to the traveling direction). The block 6 fixed to the side of the frame 1 guides the rail 5 fixed to the side end of the mover 4 so that the rail 5 can travel.

The other slide guide 7b is the frame 1
A positioning pin 12 which is provided on the inner side surface of the frame and serves as a positioning means for positioning in the vertical direction; The block 6 movably supported in the width direction of the mover 4 and the rails 5 fixed to the side ends of the mover 4 in the width direction are supported by the block 6 supported on the frame 1 side. The rail 5 fixed to the side end of the mover 4 is guided so that it can travel. Although details will be described later with reference to FIGS. 2 to 4, preload application for applying preload between the inner surface of the frame 1 on the support side (fixed side) and the block 6 of the slide guide 7b on the movable side. An elastic material such as a spring is provided as a means.

In the present invention, since the linear motor is a fully closed type, it is not necessary to consider that the load in the radial direction of the slide guides 7a and 7b becomes particularly large. Therefore, the installation direction of the slide guides 7a and 7b can be changed. As shown in FIG. 1, the slide guides 7a and 7b can be disposed so as to lie on each other and face each other. Slide guide 7
When a and 7b are set in the above-mentioned installation direction, even if some load acts on the width of the mover 4 due to the thermal expansion 20 of the mover 4, a force acts from the rail 5 to the block 6,
The slide guides 7a and 7b can withstand the original load capacity.

Further, in the present invention, the support structure of the slide guide 7b is devised by the positioning pin 12 and the projecting portions 13a and 13b so that the slide guide 7b is not affected by the thermal expansion 20 of the mover 4. This is characterized in that at least one of the blocks 6 is movably supported in the width direction of the mover 4 so that it can be slightly moved in the thermal expansion direction. Considering the rigidity of the support structure, one slide guide 7a is set as the fixed side,
It is preferable to make the other slide guide 7b movable.

Further, since at least one of the blocks 6 is movably supported in the width direction of the mover 4, the inner side surface of the frame 1 serving as the supporting side and the block 6 side of the slide guide 7b serving as the moving side. An elastic material such as a spring, which serves as a preload applying means, can be sandwiched between them, so that an appropriate preload can be applied to the block 6 and the rail 5 for traveling.

Further, in order to reinforce the rigidity of the support structure of the movable slide guide 7b, projecting portions 13a and 13b serving as support means for vertically supporting the slide guide 7b are provided on the inner surface of the frame 1 and the cover 2 to slide. The guide 7b is sandwiched between the protruding portions 13a and 13b to support the slide guide 7b. The slide guide 7b is also supported by the positioning pin 12 provided on the inner side surface of the frame 1, and supports the positioning pin 12 that supports from the same direction as the thermal expansion 20 of the mover 4 and the moving pin 4 in the traveling direction. High rigidity can be ensured by the protruding portions 13a and 13b sandwiched by the flat surfaces. Since it has the high-rigidity structure, it can be applied to, for example, a linear motor in which the thrust of the mover 4 is 1 ton class or more.

In the present invention, the movable slide guide 7b is provided.
This is a part where the support structure of (1) in FIG. 1 is characteristic,
The detailed structure of the portion A is shown in FIGS. 2, 3 and 4 (a).
Shown in.

FIG. 2 is an enlarged view of the portion A in FIG. In order to show the internal structure in detail, a part of the structure is broken away.

As shown in FIG. 2, the block 6 of the slide guide 7b is vertically positioned by a plurality of positioning pins 12 which are positioning means protruding from the inner side surface of the frame 1, and the movable element 4 is moved. It is movably supported in the width direction. Further, the frame 1 and the cover 2 are supported so as to be sandwiched from above and below in the vertical direction by projecting portions 13a and 13b which are provided as projecting means on the inner surfaces of the frame 1 and the cover 2. In addition, the block 6 of the slide guide 7b and the frame 1
A flat spring 14 having a suitable biasing force is provided as a preload applying means so that the block 6 and the rail 5 are always in contact with each other with an appropriate preload. The positioning pin 12 is provided so as to insert the flat spring 14.

In the above structure, the slide guide 7b is not fixed to the frame 1 side. That is, the position of the slide guide 7b in the vertical direction of the block 6 is only determined by the positioning pin 12, and the width of the mover 4 is absorbed to absorb the thermal expansion 20 in the width direction of the mover 4. It is a structure that movably supports the direction.

Further, since the rail 5 of the slide guide 7b is fixed to the mover 4 side and the block 6 of the slide guide 7b is supported to the frame 1 side, the mounting structure of the flat spring 14 serving as preloading means is changed to the block. It is possible to have a simple structure in which only the portion 6 is provided. When the installation structure of the block 6 and the rail 5 is reversed and the block 6 of the slide guide 7b is fixed to the mover 4 side and the rail 5 of the slide guide 7b is supported on the frame 1 side, the longitudinal direction of the rail 5 It is necessary to provide the preload applying means along a plurality of lines or in all the longitudinal directions, and the structure for providing the preload applying means becomes complicated.

The positioning pin 12 provided on the inner surface of the frame 1 has not only the function of positioning the slide guide 7b but also the function of holding the rigidity of the support structure.
Further, in order to reinforce the rigidity of the support structure of the slide guide 7b, the slide guide 7b is provided in the vertical projection 1 above and below.
It is supported so as to be sandwiched between 3a and 13b. The protruding portion 13a, 13b and the block 6 of the slide guide 7b
2, that is, portions B and C in FIG. 2 support the slide guide 7b and are movable.

With the above structure, the slide guide 7b is movably supported by the positioning pin 14, so that the mover 4 is moved.
The influence of the thermal expansion 20 of the block 6 can be absorbed, and the block 6 and the rail 5 can be brought into contact with each other by the flat spring 14 with an appropriate preload, and the projecting portion provided to sandwich the block 6 The rigidity of the support structure can be reinforced by 13a and 13b.

FIG. 3 is a sectional view of a fully closed linear motor showing another example of the embodiment according to the present invention, and is an enlarged view of a portion corresponding to the portion A in FIG.

The basic support structure of the slide guide 7b in this embodiment may be the same as that shown in FIG. However, the block 6 of the slide guide 7b and the frame 1
It is characterized in that a flat plate-like elastic body 15 made of rubber or the like is provided in place of the flat spring 14 between the inner side surface and the inner side surface.

By using the plate-shaped elastic body 15,
Compared to the case where the flat spring 14 is used, the contact area between the frame 1, the elastic body 15 and the block 6 can be increased to disperse the concentration of the load load, the rigidity of the support structure can be increased, and the slide rail can be increased. The preload applied to 7b can be increased.

Also in the above structure, the slide guide 7b
Movably supported by the positioning pin 14 can absorb the influence of the thermal expansion 20 of the mover 4,
Further, the block 6 and the rail 5 can be brought into contact with each other with an appropriate preload by the elastic body 15, and the projecting portions 13a and 13b provided so as to sandwich the block 6 reinforce the rigidity of the support structure. be able to.

FIG. 4 is a diagram of a fully-closed linear motor showing still another example of the embodiment according to the present invention. FIG. 4A is a sectional view of a portion corresponding to the portion A of FIG. 1, and FIG. FIG. 4 is a cross-sectional view of the upper surface.

The support structure of the slide guide 7b in this embodiment is different from that shown in FIGS. 2 and 3 in that a protruding portion 13c is provided on the inner side surface of the frame 1 on the supporting side, and the protruding portion 13c is provided. A plate spring 16 is provided along the longitudinal direction of the rail 5 and is fixed with a bolt 18, and the block 6 of the slide guide 7b is fixed with a bolt 17 to the plate spring 16 itself. Figure 4
In (b), the supporting structure of the slide guide 7b at one end in the longitudinal direction of the leaf spring 16 is shown, but the slide guide 7b at the other end also has the same supporting structure.

In the above structure, the leaf spring 16 serves as a positioning means for movably supporting the block 6 of the slide guide 7b in the width direction of the mover 4 and performing vertical positioning.
It also serves as a preload applying means for applying an appropriate preload to the slide guide 7b by the urging force of the leaf spring 16, and further has a function of securing the rigidity of the support structure of the slide guide 7b together with the protruding portions 13a and 13b.

In the above structure, the slide guide 7b
By movably supporting the plate spring 16, the influence of the thermal expansion 20 of the mover 4 can be absorbed, and also the block 6 and the rail 5 are contacted by the plate spring 16 with an appropriate preload. Moreover, the rigidity of the support structure can be reinforced by the protruding portions 13a and 13b provided so as to sandwich the block 6.

In the present invention, the fully closed linear motor is used as an embodiment, but the present invention is not limited to the fully closed linear motor and can be applied to other linear motors. Further, the support structure of the slide guides 7a and 7b, the support direction, and the preload applying means can be appropriately changed within the scope of the present invention.

[0045]

According to the first aspect of the present invention, in the linear motor in which the mover is linearly moved with respect to the stator fixed to the housing, the rail is fixed to both ends in the width direction of the mover. A block for guiding the rail is supported by the housing, and at least one of the blocks is movable in the width direction of the mover, and at least one of the blocks is affected by thermal expansion in the width direction of the mover. Since it absorbs by moving, the slide guide can run without being affected by the thermal expansion of the mover, and the operating temperature of the linear motor can reach the allowable temperature of the slide guide and the allowable temperature of the coil winding. It can be expensive. Further, since it can be operated at a high temperature, the cooling structure can be simplified and the size of the linear motor can be reduced.

According to the second aspect of the present invention, since the housing is provided with the positioning means for positioning the block, the slide guide can be movably supported and positioned.

According to the invention of claim 3, the rails and the blocks are arranged so as to face each other, and the force due to the thermal expansion of the mover in the width direction is received from the rail in the block direction. Therefore, even if some load acts in the width direction of the mover due to thermal expansion of the mover,
The original load capacity of the slide guide allows it to withstand the load.

According to the inventions of claims 4 to 5, since the preload applying means for applying a preload to the block is provided and the slide guides are supported through the preload applying means, the slides arranged opposite to each other. The parallelism of the mounting surface of the guide can be corrected by the preload applying means, and the processing accuracy of the parallelism can be reduced. Therefore, the linear motor can be manufactured at low cost. Further, since the spring or the elastic body serving as the preload applying means can apply the preload to the slide guide, the mover can move smoothly and can move at high speed, that is, the allowable speed increases and the work amount increases. .

According to the invention of claim 6, since the supporting means for supporting the block from the vertical direction is provided in the housing, in the supporting structure of the slide guide which absorbs the influence of thermal expansion of the mover, The rigidity of the support structure can be reinforced.

[Brief description of drawings]

FIG. 1 is a sectional view of a fully enclosed linear motor showing an example of an embodiment according to the present invention.

FIG. 2 is an enlarged view of a portion A in FIG.

FIG. 3 is a cross-sectional view of a fully closed linear motor showing another example of the embodiment according to the present invention, and is an enlarged view of a portion corresponding to a portion A in FIG. 1.

4A and 4B are diagrams of a fully-closed linear motor showing still another example of the embodiment according to the present invention, in which FIG. 4A is a sectional view of a portion corresponding to portion A of FIG. 1, and FIG. It is sectional drawing of an upper surface.

FIG. 5 is a sectional view of a conventional fully-closed linear motor.

[Explanation of symbols]

1 frame 2 cover 3 stator 4 mover 5 rails 6 blocks 7a Slide guide (fixed side) 7b Slide guide (movable side) 8 coils 10 magnets 12 Positioning pin 13a protruding portion 13b protruding part 14 Sarabane 15 Elastic body 16 leaf spring 20 thermal expansion

Claims (6)

[Claims] 1. A linear motor in which a mover is linearly moved with respect to a stator fixed to a housing, wherein rails are fixed to both ends of the mover in the width direction, and blocks for guiding the rail are provided in the housing. A linear motor which is supported by a body and at least one of the blocks is movable in a width direction of the mover. 2. The linear motor according to claim 1, wherein the housing is provided with positioning means for positioning the block. 3. The linear motor according to claim 1 or 2, wherein the rails and the blocks are arranged so as to face each other. 4. The linear motor according to claim 1, further comprising preload applying means for applying a preload to the block. 5. The linear motor according to claim 4, wherein the preload applying means is a spring or an elastic body. 6. The linear motor according to claim 1, wherein the housing is provided with support means for supporting the block from a vertical direction.