JPH07181275A - Linear moving device - Google Patents

Abstract

PURPOSE:To provide a linear moving device with easy production and assembling which is capable of improving durability without enlarging the device size and of moving accurately. CONSTITUTION:A linear moving device is constituted of a housing 1, a first roller 2 supported rotation-free with the housing 1, a second roller 3 supported rotation-free with the housing 1, a motor 6 to rotate the second roller 3 and a moving body 9 movable in a specific direction by the rotation of the second roller 3 which is pinched with the rotating surface of the first roller and the rotating surface of the second roller. And the first roller 2 is supported with supporting means 10, 11 allowing the movement to the direction of the rotation shaft of the roller 2. Or longitudinal modulus of the maternal of the moving body 9 of the linear moving device is made smaller than longitudinal modulus of the first roller 2 and the second roller 3.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a linear moving device for driving a table device used in a semiconductor device manufacturing apparatus or inspection apparatus, or a microscope or various machine tools requiring fine positioning in a predetermined direction. Regarding

[0002]

2. Description of the Related Art Here, a conventional technique of a table device of a device used for manufacturing and inspecting a semiconductor device and a linear drive device used for driving the same will be mainly described. In recent years, the degree of integration of semiconductor devices such as LSI has been improved more and more, and the line width of the pattern of the semiconductor device has become extremely fine as 1 μm or less. Along with this, the table device used in such a highly integrated semiconductor device manufacturing apparatus or inspection apparatus is required to have extremely high accuracy.

As the accuracy of the table, the straightness during the table traveling, the amount of posture change, the positioning accuracy, etc. are emphasized, and various table structures, position detecting methods, driving methods, etc. have been developed.

For driving the table, it is general to use a linear drive device using ball screws and nuts. The features of this method are that the rigidity in the feed direction is high and it is easy to reduce the vibration during positioning, and it is relatively easy to increase the dimensional accuracy of the ball screw, so it is easy to improve the position accuracy. Therefore, it is possible to drive a large load with a small motor and at the same time obtain a high resolution relatively easily. For this reason, it has become possible to perform positioning in the nanometer range by adopting a position detecting means having a very high resolution and devising a control method.

On the other hand, as a problem, it is impossible to completely eliminate the bending of the screw shaft of the ball screw, and the whirling of the ball screw occurs every rotation of the screw shaft.
It may adversely affect the accuracy of the table, generate vibration due to whirling at high speed rotation, and cause noise and vibration due to collision between balls, ball and return tube or top during ball circulation, etc. Can be raised.

This problem is not so serious in the table of an exposure machine such as a stepper which performs step and repeat, but the table is moved at a constant speed for continuous exposure and data is collected for inspection. In the apparatus, it causes a great fluctuation in the speed of the table during movement and an increase in the vibration of the table, which is a very serious problem.

Therefore, in recent years, friction driving has been increasingly used for table driving of an apparatus for continuously performing exposure or inspection at a constant speed. Friction drive is a method of linearly displacing the rod by linearly displacing the rod by sandwiching a round or square rod connected to the table with multiple rollers and rotating one roller with a motor. Is.

This drive method is characterized in that no balls or the like are used, so that vibration and noise due to ball circulation are not generated at all, and the rod is displaced by the rotation of the roller by improving the roller manufacturing accuracy. It is possible to drastically reduce the amount, and even if the table speed is high, the rotation speed of the roller is low, so even if there is eccentricity of the roller, the cycle of speed fluctuation becomes longer and it is less likely to cause vibration. .

Due to such characteristics, the friction drive device is regarded as a drive method suitable for driving a table which requires extremely high speed stability. However, as a problem, since the driving force is obtained by using the frictional force, the wear of the roller and the rod is inevitable. To obtain the large driving force, it is necessary to press the roller and the rod with a very large force. Therefore, the contact stress between the roller and the rod becomes high, the life of the surface of the roller and the rod tends to be short, and slippage may occur.

Regarding the wear of the roller and the rod, measures such as improving the hardness of the contact portion or applying traction oil to the contact portion so as not to directly contact the roller and the rod are taken. The slip can be dealt with by directly measuring the displacement of the table and correcting the slip of the roller and the rod to perform positioning.

At present, the most important issue is to improve the durability of rollers and rods. Tables of semiconductor device manufacturing / inspection equipment are often operated overnight in order to improve their productivity, and the mechanical system of the table is required to be durable enough not to require maintenance other than regular inspection. . Especially the drive unit
Since replacement is difficult, it is desirable that it can be used for as long as possible without replacement.

The most effective means of improving the durability of the friction drive device is to reduce the contact stress between the roller and the rod. Specifically, the smaller the difference in curvature between the contact surface between the roller and the rod, the lower the contact stress at the contact surface and the longer the life. For this purpose, it is effective to increase the radius of the roller, but this increases not only the size of the roller but also the size of the motor due to an increase in the roller driving force, and the size of the entire apparatus increases.

The durability has been described above by paying attention to the contact stress between the roller and the rod. However, when considering the durability of the friction drive device, it is necessary to consider the supporting portion of the roller.

Although the pressing force between the roller and the rod is very large, it is the bearing that supports the roller that supports this load. Therefore, the structure and manufacturing accuracy of the roller supporting portion have a great influence on the life of the roller supporting portion. Especially when sandwiching a round bar rod with drum-shaped rollers, if the contact position of the two rollers deviates from the original position, the radius of rotation at the contact point changes and the feed amount of the rod changes,
The contact stress between the roller and the rod may increase and the durability may be impaired. Therefore, the roller supporting portion of the friction drive device is required to have very high manufacturing accuracy and assembly accuracy.

[0015]

As described above,
A linear movement device that drives a rod by rotating rollers by sandwiching a rod-shaped rod and linearly moves a table has the characteristic that it is easy to improve speed stability. In applications that require high-frequency operation over a long period of time, the durability of the roller and the rod is not sufficient, and there is a problem that the roller and the motor become large in size in order to improve the durability.

Further, in order to maintain the durability of the roller supporting portion and enable highly accurate driving, it is necessary to increase the manufacturing accuracy and the assembly accuracy of the roller supporting portion, which increases the manufacturing cost of the apparatus. Was there.

In view of the above, according to the present invention, it is possible to easily manufacture and assemble at low cost, it is possible to improve the durability without increasing the size of the apparatus, and it is possible to drive the table with high accuracy. An object is to provide a mobile device.

[0018]

In order to achieve the above object, the present invention provides the following linear movement device. In the invention according to claim 1, the housing, the first roller rotatably supported by the housing, the second roller rotatably supported by the housing, and the second roller are rotated. A straight line composed of a rotation driving means, and a moving body that is sandwiched between the rolling surface of the first roller and the rolling surface of the second roller and is movable in a predetermined direction by the rotation of the second roller. In the moving device, the first roller is a linear moving device characterized in that it is supported by a supporting means that allows the first roller to move in the rotation axis direction.

According to the second aspect of the invention, the housing, the first roller rotatably supported by the housing, and the second roller rotatably supported by the housing.
Roller, a rotation driving means for rotating the second roller, and a predetermined direction by rotation of the second roller sandwiched between the rolling surface of the first roller and the rolling surface of the second roller. In a linear movement device composed of a movable movable body, the longitudinal elastic modulus of the material of the movable body is smaller than the longitudinal elastic modulus of the material of the first roller and the second roller. Is a linear movement device.

According to the third aspect of the invention, the housing, the first roller rotatably supported by the housing, and the second roller rotatably supported by the housing.
Roller, a rotation driving means for rotating the second roller, and a predetermined direction by rotation of the second roller sandwiched between the rolling surface of the first roller and the rolling surface of the second roller. A linear moving device comprising a movable moving body, wherein the moving body is formed of a rod-shaped body at least a part of which is hollow.

In the invention according to claim 4, the housing, the first roller rotatably supported by the housing, and the second roller rotatably supported by the housing.
Roller, a motor case connected to the housing, a stator fixed to the motor case, and a rotation fixed to the rotation shaft of the second roller to generate a rotational force between the stator and the roller. And a moving body that is sandwiched between the rolling surface of the first roller and the rolling surface of the second roller and is movable in a predetermined direction by the rotation of the second roller. It is a linear moving device.

According to a fifth aspect of the present invention, the housing, the first roller rotatably supported by the housing, and the second roller rotatably supported by the housing.
Roller, a rotation driving means for rotating the second roller, and a predetermined direction by rotation of the second roller sandwiched between the rolling surface of the first roller and the rolling surface of the second roller. In a linear movement device composed of a movable moving body, the housing has a mounting portion for mounting a supporting means for supporting the first and second rollers and a penetrating portion through which the moving body penetrates. It is a linear movement device characterized by being formed from a single member formed.

According to a sixth aspect of the present invention, the housing, the first roller rotatably supported by the housing, and the second roller rotatably supported by the housing.
Roller, a rotation driving means for rotating the second roller, and a predetermined direction by rotation of the second roller sandwiched between the rolling surface of the first roller and the rolling surface of the second roller. A linear moving device comprising a movable moving body, wherein a pressure applying means for adjusting a contact pressure between the first and second rollers and the moving body is provided. Is.

In the invention described in claim 7, by forming a plurality of grooves in the housing, a plurality of thin portions and the first or second roller elastically supported by the thin portions by the grooves are provided. A movable part that is displaceable in the normal direction of the contact portion of the movable body is integrally formed with the housing,
7. The linear movement device according to claim 6, wherein the pressure applying means is connected to the movable portion.

According to an eighth aspect of the present invention, contact force detecting means for measuring the contact pressure between the first and second rollers and the moving body, and the contact detected by the contact force detecting means. The straight line according to claim 6, further comprising: a control unit that compares the force with a target contact force and controls the magnitude of the force generated from the pressure applying unit based on the comparison result. It is a mobile device.

According to a ninth aspect of the present invention, the pressure for adjusting the value of the target contact force input to the control means on the basis of the rotational state quantity of the rotary drive means is inputted. The linear moving device according to claim 6, further comprising setting means.

[0027]

According to the invention described in claim 1, since the support means for the first roller does not restrain the displacement of the first roller in the direction of the rotation axis, the shape error of the housing or the first and second housings. Even if there is a positional deviation from the roller or an assembly error, a load is applied to the first roller in the rotation axis direction,
Since the position of the first roller can be automatically displaced (moved) to the position where the load is minimized, the durability of the roller and the moving body can be improved.

According to the second aspect of the present invention, by making the longitudinal elastic coefficient of the moving body smaller than the longitudinal elastic coefficient of the two rollers, the moving body is elastically deformed by sandwiching the moving body with the two rollers. The contact area can be increased, the contact stress can be reduced, and the durability can be improved. further,
Since the roller deformation can be suppressed small, it is possible to reduce the error in the radius of gyration at the contact point between the roller and the moving body, and at the same time, to minimize the deflection of the roller shaft.

According to the third aspect of the invention, by providing the movable body with a hollow portion, the same action and effect as in the second aspect, that is, by sandwiching the movable body with two rollers, the movable body is more elastically deformed. The contact area can be increased, the contact stress can be reduced, and the durability can be improved. Further, since the roller deformation can be suppressed small, it is possible to reduce the error of the radius of gyration at the contact point between the roller and the moving body, and at the same time, to minimize the deflection of the roller shaft.

According to the fourth aspect of the present invention, the rotor of the motor is directly fixed to the second roller shaft serving as the drive roller, and the stator of the motor is fixed to the housing, thereby manufacturing and assembling the drive device. Further, since the rotation of the motor is directly transmitted to the driving roller, highly accurate driving becomes possible.

According to the fifth aspect of the present invention, the concentricity of the roller supporting means and the concentricity of the through hole of the moving body can be improved simply by making holes in the housing. High accuracy of movement can be easily achieved.

According to the invention described in claims 6 to 9, a groove is formed in the housing to form a movable portion which is elastically supported, and the movable portion supports the first roller to form a housing. By connecting the pressure applying means between the movable parts, the force for pressing the roller against the moving body can be adjusted, so that the contact stress between the roller and the moving body can be easily prevented from becoming excessive.

Further, the preload generated by the pressure applying means is electrically variable, a means for detecting the preload is provided, and a means for adjusting the preload is provided to maintain the proper preload. The durability of the roller and the moving body can be improved.

Further, by providing pressure setting means for setting an appropriate preload in accordance with the rotational state (rotational state amount) such as the torque of the rotational drive means for rotating the second roller,
The preload can be increased only when the driving force is needed, and can be reduced when the driving force is not required such as at constant speed driving or positioning, so that the time when a large contact stress occurs can be minimized. The durability of the rod-shaped body can be improved.

[0035]

Embodiments of the present invention will now be described in detail with reference to the drawings. FIG. 1 is a sectional view showing a first embodiment of a linear movement device according to the present invention. The linear movement device shown in FIG. 1 mainly includes a frame-shaped housing 1, a first roller 2 serving as a driven roller, a second roller 3 serving as a driving roller, and a second roller connected to the second roller. A rotation driving means 6 such as an electric motor for rotating the second roller, and a rod-shaped moving body (hereinafter referred to as a rod-shaped body) 9 which is sandwiched between the first roller and the second roller and can be directly moved in a direction perpendicular to the paper surface. It is composed of

The rotation driving means 6 rotates the second roller to displace the rod-shaped body 9 and drive a table or the like (not shown) connected to the rod-shaped body 9.

The second roller 3 has a concave rolling surface 5 at the center thereof, and a valley portion of the rolling surface 4 makes point contact with the rod 9 substantially. The second roller 3 is
It is rotatably supported by supporting means 12 and 13 such as ball bearings having a double-supported structure, and at the same time, axial displacement is also restrained. As the supporting means 12 and 13, a deep groove ball bearing, an angular ball bearing or the like that can support a load in the thrust direction is used. By supporting the second roller 3 in this way, when the second roller 3 rotates, the rod-shaped body 9 that is displaced in contact with the second roller 3 in the axial direction is the shaft of the second roller 3. This prevents the displacement accuracy of the rod-shaped body 9 from deteriorating and the rotation driving means 6 from being axially loaded.

The rotation driving means 6 is connected to the housing 1 by a connecting member 14. This rotation drive means 6
Generally, an electric motor such as a DC motor or an AC motor is used. The rotation shaft 7 of the rotation driving means 6 is connected to the second roller 3 via the coupling 8 and rotates the second roller 3.

The first roller 2 has a double-supported structure in the housing 1 and has supporting means 10, 11 such as needle roller bearings.
It is rotatably supported by. This first roller 2
Since it is supported by the supporting means 10 and 11 such as a needle roller that does not have a restraining force in the rotational axis direction, it can be displaced in the axial direction of the first roller 2.

The round bar 9 is sandwiched between the rolling surface 4 of the first roller 2 and the rolling surface 5 of the second roller 3, and its thickness is set so that a certain contact force is generated. Be adjusted and incorporated.

Here, the effect of the structure in which the first roller is displaceable in the axial direction will be described with reference to FIGS. FIG. 2 is a diagram showing a contact state between the roller and the rod-shaped body when the first roller is supported by the support means for restraining the axial displacement.

In this case, since the first roller 2 is supported by the supporting means 20, 21 such as a deep groove ball bearing for restraining axial displacement, the first roller 2 is assembled at the time of assembly as shown in FIG. When the support means 20 and 21 of the second roller 3 are assembled in a state where the positional relationship between the support means 12 and 13 of the second roller 3 is deviated, the contact point between the first roller 2 and the rod-shaped body 9 and the second support means.
The position of the contact point between the roller 3 and the rod-shaped body 9 changes. Originally, the rolling surface 4 of the first roller and the rolling surface of the second roller are designed to come into contact with each other at the smallest radius. Therefore, when the contact point changes, the rolling radius of the roller at the contact point changes. The displacement amount of the rod-shaped body 9 per rotation of the second roller 3 increases, and the positioning accuracy deteriorates.

Further, since the distance between the contact points of the two rollers 2 and 3 becomes smaller, but the radius of the rod-shaped body 9 does not change, the contact stress at the contact point increases and the durability of the roller or the rod-shaped body deteriorates. Will end up. Two more rollers 2, 3
Axial load is applied to the supporting means 20, 21, 1
An excessive axial load is applied to 2 and 13 to support means 20,
The durability of 21, 12, and 13 is also reduced. Therefore, in order to avoid such a situation, the assembling accuracy of the first roller 2 must be made extremely high.

The above problems become more remarkable as the diameters of the first roller 2 and the second roller 3 are made smaller to reduce the size of the apparatus, and the contact stress at the contact point is made smaller. The smaller the radius of curvature of the rolling surfaces 4 and 5 of the two rollers becomes, the more remarkable it becomes.

FIG. 3 is a view showing a contact state between the roller and the rod-shaped body of the linear movement device of the present invention shown in FIG. In the linear movement device of the present invention, the support portion 10 of the first roller 2 is
Since 11 does not restrain the axial displacement of the first roller 2,
Even if there is a shape error in the housing 1 as shown in FIG. 3, by inserting the rod-shaped body 9 between the rolling surface 4 of the first roller and the rolling surface 5 of the second roller, Even if the first roller 2 and the second roller 3 are misaligned with each other, an axial load is applied to the first roller 2 and the first roller 2 is axially displaced to a position where the load is minimized. .

Therefore, the support means 1 for the first roller 2
The housing 1 is processed with high precision for 0 and 11,
When assembling the first roller 2, it is not necessary to perform a complicated adjustment work for alignment, and at the same time, the two rollers 2, 3 and the rod-shaped body 9 and the supporting means 10, 11, 12,
The durability of No. 13 is not reduced. Further, the roller rotation radius at the contact point does not change, and the displacement amount of the rod-shaped body 9 per one rotation of the second roller does not change, so that highly accurate displacement can be maintained.

Although the linear moving device in which the first roller and the second roller are supported by the housing in a double-supported structure has been described above, as shown in FIG.
2. Even when the second roller 43 is supported by the housing 41 in a cantilever structure, the same effect can be obtained.

It has been described above that the durability of the roller and the rod-shaped body can be prevented from being lowered by the present invention. Further, in order to improve the durability of the roller and the rod-shaped member, in the present invention, the rod-shaped member and the roller are made of materials having different longitudinal elastic moduli (also called Young's modulus or elongation elastic modulus).

Specifically, the rod-shaped body 9 shown in FIG.
The roller 2 and the second roller 3 are made of a material having a smaller longitudinal elastic modulus. The effect of this will be described below with reference to FIGS. 5, 6 and 7.

FIG. 5 is a view showing a state in which the rod-shaped body is sandwiched by applying a pressing force with two rollers, and FIG. 6 is an enlarged view showing the state of the contact surface of the portion A in FIG. FIG. 7 is an enlarged view showing a contact state when the rod-shaped body is made of a material having a longitudinal elastic modulus smaller than that of the roller.

As shown in FIG. 5, the rod-shaped body 9 has a size P
It is sandwiched between the first roller 2 and the second roller 3 with the pressing force of 50 and 51. At this time, the second roller 3 and the rod-shaped body 9
Both surfaces undergo elastic deformation at the contact point 53 of FIG.
The elliptical contact surface 63 is formed on the rod-shaped body 69 as shown in FIG. The size of the contact surface 63 is determined by the longitudinal elastic coefficients of both materials unless the curvatures of the rolling surface of the second roller and the rolling surface of the rod-shaped body 9 change. If the pressing forces 51 and 52 shown in FIG. 5 are constant, the larger the area of the contact surface 63 in FIG. 6, the smaller the contact stress at the contact surface 63. Therefore, in order to improve the durability of the roller and the rod-shaped member, the contact surface is improved. 63 should be made as large as possible.

Therefore, if the longitudinal elastic modulus of the two rollers and the rod-shaped body is reduced, the contact stress can be reduced in principle, but if the longitudinal elastic modulus of the roller is reduced, the pressing forces 50 and 51 shown in FIG. As a result, the first roller 2 and the second roller 3 are flexibly deformed, and an excessive load is applied to the supporting means 10 and 11 of the first roller shown in FIG. Further, since the first roller 2 and the second roller 3 are repeatedly bent and deformed, the durability of the first roller 2 and the second roller 3 is reduced.

Therefore, the first roller 2 and the second roller 3 are manufactured by using a material having a longitudinal elastic coefficient such that the flexural deformation due to the applied pressure is subsided within an allowable value, and the rod-shaped body 9 is longitudinally formed from these materials. It is made of a material with a small elastic coefficient. As a result, due to the contact between the roller and the rod-shaped body, the rod-shaped body is elastically deformed more, a larger contact surface 73 is formed on the rod-shaped body 79 as shown in FIG. 7, and the contact stress of this contact surface 73 is reduced. , Durability is improved.

As a specific material, a cemented carbide using tungsten carbide or the like is used as the material of the roller, and the longitudinal elastic modulus is smaller than that of cemented carbide as the material of the rod-shaped body, but the required surface hardness is obtained. The iron-based tool steel used is used.

By devising the material of the rod-shaped body,
Although it has been described that the durability of the roller and the rod-shaped body can be improved, the same effect can be obtained by devising the shape of the rod-shaped body.

FIG. 8 is a diagram showing a linear moving device using a rod-shaped body 89 having a hollow portion as a rod-shaped body in the linear moving device shown in FIG. The linear moving device shown in FIG. 8 has exactly the same configuration and operation as the linear moving device shown in FIG. 1 except for the sectional shape of the rod-shaped body 89. In addition,
This rod-shaped body 89 has a hollow cross-sectional shape, but it is not necessary to have a hollow portion over the entire length of the rod-shaped body 89, and at least a portion that comes into contact with the first roller 2 and the second roller 3 is hollow. The structure is sufficient, and the effect of the present invention can be sufficiently obtained even if other portions are solid portions. Further, even when the material of the rod-shaped body 89 is the same as the material of the first roller 2 and the second roller 3, the effect of the present invention can be obtained.

FIG. 9 shows a first example of the linear moving device shown in FIG.
FIG. 9 is an exaggerated view of deformation of the roller 2, the second roller 3, and the rod-shaped body 89 in a contact state. The rod-shaped body 89 is
It is sandwiched between the first roller 2 and the second roller 3 by the pressing forces 90 and 91, and is deformed into an elliptical shape as shown in the figure. As a result, the contact area is increased as shown in FIGS. 6 and 7, the contact stress at the contact points 92 and 93 in FIG. 9 is reduced, and the first roller 2, the second roller 3 and the rod-shaped body are reduced. 89
Durability is improved.

In the above description, the rod-shaped body has a circular cross-section, but if the rolling surface has a convex cross-section, the same effect can be obtained with an arc or hyperbolic ellipse. Further, the same effect can be obtained even when the roller has a flat surface other than the rolling surface and the number of contact points with the roller is not one but two.

This also applies to the rolling surfaces of the first roller and the second roller, and if the rolling surface has a concave surface, the effect of the present invention is different whether it is an arcuate cross section or a V groove cross section. Absent.

The embodiments of the linear movement device according to the first invention of the present application have been described above. Hereinafter, an embodiment of the linear movement device according to the second invention of the present application will be described. Figure 10
FIG. 3 is a diagram showing an embodiment of a linear movement device according to the present invention.

This linear movement device has the same structure and operation as the linear movement device shown in FIG. This linear movement device housing 101
Are formed from a single member. Specifically, a single member is provided with holes surrounding the first roller 102, the second roller 103, and the rod-shaped body 107, and supporting means 114, 115, 1 for the first roller 102 and the second roller 103.
It is manufactured by making holes for holding 16, 117, or by forming these holes by casting.

By manufacturing the housing 101 in this manner, the number of parts of the linear movement device is reduced and the assembly is facilitated. Further, the hole portion for holding the supporting means 114, 115 for supporting the first roller 102, and the second roller 1
Since the holes for holding the supporting means 116 and 117 for supporting 03 can be processed at the same time, the concentricity of the holes for holding the supporting means 114 and the holes for holding the supporting means 115, and the supporting means 116 are held. Hole and supporting means 1
The concentricity of the holes holding 17 can be easily increased in accuracy.

Therefore, the first roller 102 and the second roller 10 do not require complicated processing and assembly.
3 can be assembled with high precision, and the cost required for manufacturing and assembling can be reduced.

A rotor 106 that generates a rotational force is directly fixed to the second roller 103, and a stator 105 that generates a rotational force on the rotor 106 is fixed to the housing 101. It is fixed inside 104. Further, the second roller 103 is connected with a rotational position detecting means 108, and a detector 107 for detecting this is fixed to the motor case.

The rotor 106 and the stator 105 are the same as the rotor and the stator of a commonly used electric motor, and the rotor 106 has a permanent magnet and the stator 105.
Various modifications are conceivable, such as one having a magnetic pole wound with an exciting winding, and one having a magnetic pole wound with an exciting winding on the rotor 106 and a permanent magnet on the stator 105.

With this structure, the rotational force generated in the rotor 106 can be directly transmitted to the second roller 103 without passing through a coupling or the like. There is no reduction in rotational rigidity, hysteresis, or fluctuations in rotational speed due to a transmission means such as a ring.

Therefore, it becomes possible to rotate the second roller 103 with high accuracy and linearly displace the rod-shaped member 109 with high accuracy for positioning. In the linear movement device shown in FIG. 10, the rotational position detecting means 108 is connected to the rotor 106 side of the second roller 103, but the rotational position is provided at the opposite end of the second roller 103. Detection means 108
Even if the detector 107 is connected to the housing 101 and the detector 107 is fixed to the housing 101, the same effect can be obtained.

FIG. 11 is a diagram showing a further embodiment of the linear movement device according to the present invention. With this linear movement device,
The housing 121 has two movable parts 126a and 126b.
The movable portion 126a holds the supporting means 127a of the first roller 102, the movable portion 126b holds another supporting means 127b, and the preload generating means 120a is provided between the movable portion 126a and the housing 121. The preload generating means 1 is connected between the movable portion 126b and the housing 121 by connecting them.
20b is connected. Other parts are similar to those of the linear movement device shown in FIG.

FIG. 12 is a side view of the linear moving device shown in FIG. 11 as seen from the direction C. The movable part 126a is formed in the housing 121 by wire-cut electric discharge machining or the like.
It is formed by processing 22a, 123a, 124a, and 125a. In addition, the movable portion 126a has a groove 122.
Since it is supported by the four thin portions 126a formed simultaneously by a, 123a, 124a, and 125a,
A slight displacement can be made in the 110 direction in the figure.

Since the movable portion 126b on the opposite surface to the side surface shown in FIG. 12 may have the same shape as the movable portion 126a, when the movable portions 126a and 126b are machined in the housing 121, the wire may be penetrated to the opposite surface. It can be formed at the same time by performing cut electric discharge machining.

A preload generating means 120a capable of generating a load in the 110 direction in the drawing is connected between the movable portion 126a and the housing 121. The preload generating means 120b is similarly connected to the movable portion 126b.
A spring, a piezoelectric element, a magnetostrictive element, or the like is used as the preload generating means.

With this structure, the rod-shaped member 109, the first roller 102, and the second roller 1 can be easily formed without increasing the number of parts other than the preload generating means.
The contact force of 03 can be adjusted to adjust the contact force required to drive the rod-shaped body 109. Therefore, it is possible to properly maintain the contact force between the roller and the rod-shaped body, and it is possible to prevent the contact force from becoming excessive and the durability of the roller and the rod-shaped body from being deteriorated.

However, this is a case where the manufacturing precision of the rod-shaped body 109 is ideal, and it is actually difficult to make the thickness of the rod-shaped body 109 constant. When the thickness of the rod-shaped body 109 is not constant, even if the generated preload of the preload generation means 120a and 120b is set to an appropriate value, the generated preload varies to some extent as the rod-shaped body 109 moves. When the generated preload fluctuates, the friction torque at the supporting portions of the first roller 102 and the second roller 103 fluctuates, and the rotational force required for the second roller 103 changes.

In particular, when positioning the rod-shaped body 109, the first
The difference in friction torque between the roller 102 and the second roller 103 adversely affects the positioning accuracy. This becomes remarkable when solid-state elements such as piezoelectric elements and magnetostrictive elements are used as the preload generating means 120a and 120b. This is because in these solid-state devices, the load generated by slight deformation of the device changes significantly.

In order to solve this problem, the present invention further provides a linear movement device shown in FIG. This linear moving device adopts a preload generating means of the linear moving device shown in FIG. 12 that can change the generated load by an electric signal such as a piezoelectric element or a magnetostrictive element, and further uses the preload generating means as the preload generating means. The preload detection means is connected.

Signal cables 133a and 133b are connected to the preload generating means 130a and 130b, respectively, and the generated load can be varied by an electric signal. Preload detecting means 131a and 131b are connected between the housing 121 and the preload generating means 130a and 130b, respectively. A load cell using a strain gauge or the like is used as the preload detection means 131a and 131b.
Although the preload detecting means 131a, 131b are installed between the preload generating means 130a, 130b and the housing 121 in FIG. 12, the preload generating means 130a, 1b are installed.
A configuration in which it is installed between 30b and the movable portions 136a and 136b is also conceivable.

With such a structure, the magnitude of the preload generated in the preload generating means 130a and 130b can be detected, so that the rod-shaped body 109 comes into contact with the first roller 102 and the second roller 103. The power can be revealed.

Therefore, the fluctuation of the contact force with the roller due to the manufacturing error of the rod-shaped body 109 is detected, and the pre-pressure generated by the pre-pressure generating means 130a and 130b is adjusted by the electric signal so that the contact force becomes constant. You can This realizes a linear movement device in which the positioning accuracy does not change depending on the position of the rod-shaped body 109 and the durability of the rod-shaped body 109 does not partly deteriorate. Further, since it is not necessary to excessively increase the manufacturing accuracy of the rod-shaped body 109, it is possible to reduce the manufacturing cost of the rod-shaped body 109.

The above is not limited to the linear moving device using the roller having the concave rolling surface and the rod-shaped body having the convex rolling surface as shown in FIG. It is also effective for a linear movement device using a roller having a cylindrical rolling surface and a rod-shaped body having a flat rolling surface as shown in FIG.

FIG. 14 is a diagram showing a further embodiment of the linear movement device according to the present invention. With this linear movement device,
The first roller 142 and the second roller 143 have cylindrical rolling surfaces 144 and 145. The rod-shaped body 149 sandwiched between these has flat rolling surfaces 154 and 155 extending in the direction perpendicular to the paper surface of the drawing, and makes linear contact with the first roller 142 and the second roller 143. It is driven in the direction perpendicular to the paper surface. Movable parts 146a and 146b formed in the housing 141, preload generation means 150a and 150b, preload detection means 151a and 151b.
Other parts are the same as those of the linear movement device shown in FIG. 13, and their operations are also the same.

Even in this linear moving device, it is inevitable that the distance between the rolling surfaces 154 and 155 is partially different due to the manufacturing error of the rod-shaped body 149. Therefore, the preload generating means 150a,
The preload amount generated by 150b is determined by the preload detection means 151a, 1
By detecting at 51b, the generated preload can be kept constant and the positioning accuracy can be maintained. Further, in this way, the first roller 142, the second roller 143 and the rod-shaped body 1
When 49 makes line contact, not only the distance between the two rolling surfaces 154 and 155 of the rod-shaped body 149, but also the parallelism error of the first roller 142 or the second roller 1
43 and the rod-shaped body 149 may be one-sided, or the contact stress in the vicinity of the corner of the rod-shaped body 149 may become excessive, which may impair the durability.

In the linear moving device shown in FIG. 14, the amount of preload applied to the first roller 142 by the two preload detecting means 151a and 151b is detected near both ends of the roller, and the two preload generating means 150a and 150b are used. Since the first roller 142 can be adjusted, it can be prevented that the first roller 142 hits the rod-shaped body 149 one-sided or the contact force is partially excessive.

The embodiments of the linear moving device of the present invention have been described above. Hereinafter, a control method (control device) for the linear movement device described above will be described. FIG. 15 is a diagram showing a schematic configuration of a linear movement device and its control device according to the present invention.

In the linear moving device 160 shown in FIG. 15, movable parts 166a and 166b are formed on the housing 161, and the first roller 1 is formed on the movable parts 166a and 166b.
62 is rotatably supported, the housing 161 is rotatably supported by the second roller 163, and the second roller 163 is connected to the rotation driving means 164, and the rod-shaped body 169 is provided.
Is sandwiched between the first roller 162 and the second roller 163.

The rod-shaped body 169 is driven in the direction perpendicular to the paper surface by the second roller 163 rotated by the rotation driving means 164 such as an electric motor controlled by the rotation control means 165 which receives the rotation command 172 as an input.

At this time, the first roller 162 and the second roller 162
The contact force between the roller 163 and the rod-shaped body 169 is detected by the preload detecting means 168a and 168b, and the output thereof is input to the preload adjusting means 170. In the preload adjusting means 170, the proper preload set value 171 required for driving the rod-shaped body 169 is set.
And the outputs of the preload detection means 168a, 168b are compared, and a drive signal is output to the preload generation means 167a, 167b so that the actual preload amount matches the preload set value. As a result, the contact force with the rollers 162 and 163 can be kept constant even if there is a slight error in the manufacturing accuracy of the rod-shaped body 169.

Details of the preload adjusting means 170 will be described. FIG. 16 is a block diagram showing the configuration of the preload adjusting means. The preload adjusting means 170 includes the preload detecting means 16
Preprocessing means 17 for amplifying the output of No. 8 and outputting preload amount information
3, the output of the pre-processing means 173 and the preload set value 171
And a deviation generating means 174 for outputting a deviation output proportional to the difference, and amplifying the output of the deviation generating means 174,
Further, it comprises an amplifying means 175 for compensating the control system such as an integral element or a differential element, and a driving means 176 for further amplifying the output of the amplifying means 175 and outputting a drive signal to the preload generating means 167 such as a piezoelectric element. There is.

A distortion amplifier or the like is used as the preprocessing means 173, and a high voltage power amplifier or the like is used as the driving means 176. Deviation generating means 174, amplifying means 1
An analog electric circuit using an operational amplifier or the like is generally used as 75, and the output of the preprocessing means 173 is A /
The D-converted digital information is taken into a computer, the deviation is calculated by a software program, the amplifying means 175 is further operated by software, the information is D / A-converted again, and output to the driving means 176. It is also possible.

The control device of the linear moving device that keeps the contact force with the roller constant when the rod-shaped body is driven and does not adversely affect the durability and positioning accuracy of the rod-shaped body has been described above.

In the following, a control device for a linear movement device that can further improve the durability of the rod-shaped body and the positioning accuracy will be described. Since the linear moving device according to the present invention drives the rod-shaped body that is the driven body by using the frictional force, the driving force that can be generated by the rod-shaped body is substantially proportional to the contact force between the roller and the rod-shaped body. Therefore, a large contact force is required to generate a large driving force on the rod-shaped body. A large driving force is required for the rod-shaped body when the rod-shaped body is accelerated or decelerated, and a large driving force is not required for driving the rod-shaped body at a constant speed or for positioning.

Considering that the larger the contact force, the lower the durability of the roller and the rod-shaped body, and the frictional torque of the roller increases, which lowers the positioning accuracy. Acceleration / deceleration when driving the rod-shaped body. If the contact force between the roller and the rod-shaped body is increased only when a large driving force is required, the durability of the roller and the rod-shaped body can be maximized and the positioning accuracy can be improved.

Therefore, the present invention provides a control device for a linear movement device as shown in FIG. The control device shown in FIG. 17 is the rotation control means 1 for controlling the rotation drive means 164 in the linear movement device and the control device shown in FIG.
A rotation state amount 178 such as a rotation angle, a rotation speed, and a torque is input from 65, an appropriate preload amount at that time is calculated by using these information, and a preload setting value is output to the preload adjusting means 170. It has means 177.

With this configuration, when the rotation command 172 is input to the rotation control means 165, the preload setting means 177 calculates an appropriate preload amount in accordance with the rotation state, and the preload setting value is also used. The preload adjusting means 170 can control the preload of the linear movement device 160, and the rod-shaped body 169 can be driven in a state where the durability of the roller and the rod-shaped body is constantly improved and the positioning accuracy is improved.

The processing of the rotation control means 165 and the preload setting means 177 for outputting the rotation state quantity 178 will be described below. FIG. 18 is a block diagram showing a method of outputting the rotation state quantity from the rotation control means to the preload setting means.

The rotation control means 180 inputs a speed command 181 as a rotation command. The speed control unit 182 uses the position / speed information 184 output from the rotation driving unit 164.
And a control signal 186 based on the speed command 181 and the power amplifier 1
Output to 83. The power amplification unit 183 outputs a predetermined exciting current 185 to the rotation driving unit 164 based on the signal. Since the magnitude of the exciting current 185 indicates the magnitude of the torque generated by the rotation driving means 164, the power amplifying section 183 detects the exciting current and outputs the torque information 187 to the preload setting means 177. The preload setting means 177 calculates an appropriate preload based on this torque information 187.

According to this method, the torque generated by the rotation driving means 164 can be easily detected and output to the preload setting means 177. Therefore, even if the simple rotation control means 180 as shown in FIG. 18 is used, the rotation driving means 164 rotates. Preload can be set according to the condition.

The position / speed information 184 input to the rotation control means 180 here is output from the rotation drive means 164 in this embodiment, but it does not necessarily have to be output from the rotation drive means 164. The same effect can be obtained by a configuration in which the displacement of the rod-shaped body 169 shown in FIG. 17 is detected by using another position / speed detecting means (not shown) and is output to the rotation control means 180. This also applies to the subsequent embodiments.

FIG. 19 is a block diagram showing a further method of outputting the rotational state quantity from the rotation control means to the preload setting means. The rotation control unit 190 shown in FIG. 19 inputs the speed command 191 to the speed control unit 192 and inputs the position / speed information 195.
The torque command 196 is output to the torque control unit 193 based on the above. The torque control unit 193 outputs a control signal 197 to the power amplification unit 194 so that a predetermined torque is generated, and the power amplification unit 194 outputs an exciting current 198 to the rotation driving unit 164. Torque command 19 output by the speed control unit 192
Since 6 already has the torque information of the rotation driving means 164, by outputting this to the preload setting means 177, the preload adjustment according to the rotation state of the rotation driving means 164 can be performed.

Since this configuration uses the output of the speed control unit 192 in the preceding stage to the power amplification unit 194, it has a characteristic that it is not easily affected by noise and the like due to power amplification. FIG. 20 is a block diagram showing a further method of outputting the rotation state quantity from the rotation control means to the preload setting means.

The rotation control means 200 shown in FIG. 20 drives the rotation drive means 164 with the position command 209 as an input. The trajectory generation unit 205 calculates the rotational trajectory based on the position command 209, and calculates the position, speed, and
The acceleration is determined, the position command 206 is sent to the position control unit 201, the speed feedforward amount 207 is sent to the speed control unit 202, and the torque feedforward amount 208 is sent to the torque control unit 203.
Are output respectively. This torque feedforward amount 208 has theoretical torque information when it operates in accordance with the calculated trajectory, and therefore, by outputting this torque feedforward amount 208 to the preload setting means 177, Preload adjustment can be performed according to the rotating state.

The feature of this configuration is that the preload setting means 1
Since the rotational state amount output to 77 is a theoretical value, a stable rotational state amount can be output to the preload setting means 177 as compared to the previous embodiments using the control amount, so that more stable and smooth preload adjustment can be performed. It is possible.

FIG. 21 is a block diagram showing a further method of outputting the rotation state quantity from the rotation control means to the preload setting means. The rotation control means 210 shown in FIG.
It has basically the same configuration as the rotation control means 200 shown in FIG. However, the position information 211 such as the position deviation is output from the position control unit 201 to the preload setting unit 177.

The preload setting means 177 includes the rotary drive means 1
Since the 64 pieces of torque information 208 and the position information 211 are input, it is possible to adjust the preload amount in accordance with the torque generated by the rotation driving means 164 and at the same time further adjust the preload amount in accordance with the position or position deviation. Become.

Specifically, when the positional deviation becomes a certain value or less during positioning, the preload amount is further reduced or fine positioning is performed, or the preload amount is increased after the positioning is completed to increase the friction torque. This makes it possible to increase the stability of positioning.

FIG. 22 is a block diagram showing a method of outputting the rotation state quantity from the rotation control means to the preload setting means.
In this embodiment, the position or speed information 225 output from the rotation driving means 164 is input to the state quantity calculation unit 224, acceleration information is generated by applying a process such as differentiation to this information, and the information is used as a torque. The information 226 is output to the preload setting means 177. The state quantity calculation unit 2
Of the information generated in 24, speed information 226 is output to the speed control unit 222 and used for speed control.

A characteristic of this structure is that the torque information of the rotary drive means 164 can be obtained only from the position or speed information, so that the rotation control means 220, which is difficult to obtain the torque information of the rotary drive means 164, such as a motor, can be easily used. It is possible to adjust the preload according to the rotational torque. As described above, the position / speed information 225
The same effect can be obtained not only with the output from the rotation driving means 164, but also with the one obtained by separately detecting the position and speed of the rod-shaped body.

The method of outputting the rotation state quantity from the rotation control means to the preload setting means has been described above. Next, the preload setting method in the preload setting means will be described.

FIG. 23 is a graph showing a preload setting method when the rotary drive means is driven by a trapezoidal velocity curve. The upper graph 231 shows the rotation speed of the rotary drive means, the middle graph 232 shows the torque at that time, and the lower graph 233 shows the preload set value in this case.

The processing of the preload setting means proceeds as follows. First, the minimum preload p that has been set up to t0 at the start of rotation
0 is set, and from the start t0 of rotation to the end t1 of acceleration, a preload amount p1 is set by adding a preload amount proportional to the acceleration torque T1 to p0. In the constant speed section from the acceleration end t1 to the deceleration start t2, a preload amount p2 is set by adding a preload amount proportional to the torque T2 for compensating the frictional force to p0. In the deceleration section from deceleration start t2 to stop t3, a preload amount obtained by adding a preload amount proportional to the absolute value of the deceleration torque T3 to p0 is set.

By setting the preload as described above, the preload amount can be increased and the driving force can be secured only when the torque is required. Therefore, the average contact force between the roller and the rod-shaped member is smaller than that in the case of driving with a constant preload. It is greatly reduced and durability is improved.

FIG. 23 shows the preload setting when the rotary drive means is driven by the trapezoidal speed curve. However, even when the rotary drive means is driven by other speed curves, the preload amount proportional to the absolute value of the torque is set to the minimum. The same effect can be obtained by setting the preload set value in addition to the preload amount.

[0112]

As described above, according to the present invention,
It is possible to provide a linear movement device that is easy to manufacture and assemble, can improve durability without increasing the size of the device, and can drive a table with high accuracy.

[Brief description of drawings]

FIG. 1 is a plan view showing an embodiment of a linear movement device of the present invention.

FIG. 2 is a diagram showing a contact state between a roller and a rod-shaped body of a linear movement device of a conventional example.

3 is a diagram showing a contact state between a roller and a rod-shaped body of the linear movement device shown in FIG.

FIG. 4 is a plan view showing an embodiment of a linear movement device of the present invention.

5 is a diagram showing a pressing force applied to a roller of the linear movement device shown in FIG. 1 and a contact state.

FIG. 6 is a view showing a state of contact points on a rod-shaped body when the rod-shaped body of the conventional example is used.

FIG. 7 is a view showing a state of contact points on the rod-shaped body when the rod-shaped body of the present invention is used.

FIG. 8 is a plan view showing an embodiment of a linear movement device of the present invention.

9 is a diagram showing a contact state between a roller and a rod-shaped body of the linear movement device shown in FIG.

FIG. 10 is a sectional view showing an embodiment of a linear movement device of the present invention.

FIG. 11 is a sectional view showing an embodiment of a linear movement device of the present invention.

FIG. 12 is a side view showing the linear movement device shown in FIG. 11 from the direction C.

FIG. 13 is a sectional view showing an embodiment of a linear movement device of the present invention.

FIG. 14 is a sectional view showing an embodiment of a linear movement device of the present invention.

FIG. 15 is a diagram showing an embodiment of a control device for a linear movement device of the present invention.

16 is a block diagram showing details of the preload adjusting means shown in FIG.

FIG. 17 is a diagram showing an embodiment of a control device for a linear movement device of the present invention.

FIG. 18 is a block diagram showing a configuration example of the rotation control means shown in FIG.

FIG. 19 is a block diagram showing a configuration example of the rotation control means shown in FIG.

20 is a block diagram showing a configuration example of the rotation control means shown in FIG.

21 is a block diagram showing a configuration example of the rotation control means shown in FIG.

22 is a block diagram showing a configuration example of the rotation control means shown in FIG.

23 is a graph showing a preload setting method of the preload setting means shown in FIG.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1, 101 Housing 2, 102 1st roller 3, 103 2nd roller 6 Rotation drive means 9, 109 Rod-shaped body (moving body) 10, 11 1st roller support means 104 Motor case 105 Stator 106 Rotor 126a, 126b Movable part 120a, 120b, 130a, 130b Preload generating means (pressure applying means) 131a, 131b Preload detecting means (contact force detecting means) 165 Rotation control means 170 Preload adjusting means (control means) 177 Preload setting means (pressure) Setting means) 178 Rotation state quantity

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI Technical display location H01L 21/66 Z 7630-4M 21/68 K // B23Q 5/38 C

Claims (9)

[Claims] 1. A housing, a first roller rotatably supported by the housing, a second roller rotatably supported by the housing, and a rotation driving means for rotating the second roller. A linear moving device including a moving body that is sandwiched between the rolling surface of the first roller and the rolling surface of the second roller and is movable in a predetermined direction by rotation of the second roller, The linear moving device, wherein the first roller is supported by a supporting means that allows the first roller to move in the rotation axis direction. 2. A housing, a first roller rotatably supported by the housing, a second roller rotatably supported by the housing, and a rotation driving means for rotating the second roller. A linear moving device including a moving body that is sandwiched between the rolling surface of the first roller and the rolling surface of the second roller and is movable in a predetermined direction by rotation of the second roller, A linear moving device characterized in that the longitudinal elastic modulus of the material of the moving body is smaller than the longitudinal elastic coefficients of the materials of the first roller and the second roller. 3. A housing, a first roller rotatably supported by the housing, a second roller rotatably supported by the housing, and a rotation driving means for rotating the second roller. A linear moving device including a moving body that is sandwiched between the rolling surface of the first roller and the rolling surface of the second roller and is movable in a predetermined direction by rotation of the second roller, A linear moving device, characterized in that the moving body is composed of a rod-shaped body at least a part of which is hollow. 4. A housing, a first roller rotatably supported by the housing, a second roller rotatably supported by the housing, a motor case connected to the housing, and a motor. A stator fixed in a case; a rotor fixed to a rotation shaft of the second roller to generate a rotational force between the stator;
A linear moving device which is comprised of a rolling surface of the roller and a moving body which is held between the rolling surface of the second roller and is movable in a predetermined direction by the rotation of the second roller. 5. A housing, a first roller rotatably supported by the housing, a second roller rotatably supported by the housing, and a rotation driving means for rotating the second roller. A linear moving device including a moving body that is sandwiched between the rolling surface of the first roller and the rolling surface of the second roller and is movable in a predetermined direction by rotation of the second roller, The housing is composed of a single member in which a mounting portion for mounting a supporting means for supporting the first and second rollers and a penetrating portion through which the moving body penetrates are formed. Linear movement device. 6. A housing, a first roller rotatably supported by the housing, a second roller rotatably supported by the housing, and a rotation driving means for rotating the second roller. A linear moving device including a moving body that is sandwiched between the rolling surface of the first roller and the rolling surface of the second roller and is movable in a predetermined direction by rotation of the second roller, A linear movement device comprising pressure applying means for adjusting the contact pressure between the first and second rollers and the moving body. 7. A method of forming a plurality of grooves in the housing to form a plurality of thin portions by the grooves and elastically supported by the thin portions and a contact portion between the first or second roller and the moving body. 7. The linear moving device according to claim 6, wherein a movable portion that is displaceable in a line direction is integrally formed with the housing, and the pressure applying means is connected to the movable portion. 8. A contact force detecting means for measuring a contact pressure between the first and second rollers and the moving body, and a contact force detected by the contact force detecting means and a target contact force. 7. The linear movement device according to claim 6, further comprising: a control unit that controls the magnitude of the force generated from the pressure applying unit based on the comparison result. 9. A pressure setting means for inputting a rotational state amount of the rotary drive means and adjusting a value of a target contact force input to the control means based on the rotational state quantity. The linear movement device according to claim 6.