JP2003148581A - Frictional driving device and measuring machine using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a frictional driving device capable of securing upright in moving of a lifting member and to provide a measuring machine capable of improving the accuracy in measuring. SOLUTION: This frictional driving device for vertically driving a Z-axis spindle 12 guided by a guide cylinder 22, comprises a supporting shaft 28 mounted approximately in parallel to the guide direction by the guide cylinder 22 near a position of a center of gravity of the Z-axis spindle, a pair of driving roller 15 and driven roller 16 mounted on the Z-axis spindle 12 for holding the supporting shaft 28 therebetween, and a motor 17 for rotating the driving roller 15.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a friction drive device and a measuring machine using the same. Specifically, the present invention relates to a friction drive device for vertically moving an elevating member and a measuring machine using the friction drive device.

[0002]

2. Description of the Related Art A Z-direction drive mechanism for vertically moving an elevating member is known. Such a Z-direction drive mechanism for the elevating member is used in, for example, a coordinate measuring machine that measures the position and / or coordinates of a measurement target.
Conventionally, as shown in FIG. 5, a Z-direction drive mechanism has a Z-axis spindle 1 having a probe 13 at a lower end and vertically supported.
2, a guide member 22 for guiding the Z-axis spindle 12 in the vertical direction, a ball screw shaft 221 provided in parallel with the moving axis of the Z-axis spindle 12, and the Z-axis spindle 1
2 is provided with a ball screw nut 222 that is screwed onto the ball screw shaft 221 and a drive motor 223 that rotationally drives the ball screw shaft 221.

The guide member 22 has a guide tube portion 22A, through which the Z-axis spindle 12 is vertically movable. An air bearing 23 is provided on the inner circumference of the guide cylinder portion 22A, and an air bearing is formed between the guide member 22 and the Z-axis spindle 12 by an air film between the air bearing 23 and the Z-axis spindle 12. Has been reduced. The guide member 22 includes
A column 25 is provided upright vertically. A horizontal beam 26 perpendicular to the moving axis of the Z-axis spindle 12 is formed on the upper end of the column 25 so as to cover the upper side of the Z-axis spindle 12. Ball screw shaft 221
Are provided on the guide member 22 in parallel with the movement axis of the Z-axis spindle 12 and at regular intervals. The upper end of the ball screw shaft 221 is supported by the lateral beam 26 of the support column 25, and the lower end of the ball screw shaft 221 is supported by the belt 224 by the drive motor 2.
It is linked with 23.

A support shaft 28 is inserted through the Z-axis spindle 12 so as to pass near the center of gravity thereof.
The horizontal beam 26 of the support column 8 is swingably supported at its upper end. An air balance mechanism for generating a pushing force commensurate with the weight of the Z-axis spindle 12 is provided between the support shaft 28 and the Z-axis spindle 12, but a detailed description thereof will be omitted. The ball screw nut 222 is fixed to the Z-axis spindle 12 via a coupling member 121 provided on the outer surface of the Z-axis spindle 12, and is screwed to the ball screw shaft 221.

In such a structure, the drive motor 22
When 3 is rotationally driven, the ball screw shaft 221 is rotated. Then, the ball screw shaft 221 and the ball screw nut 2
The ball screw nut 222 is moved along the ball screw shaft 221 by screwing with the ball screw 22. Since the driving force of the ball screw nut 222 is transmitted to the Z-axis spindle 12 via the coupling member 121, the Z-axis spindle 12 is driven vertically. Guide member 22 and Z-axis spindle 1
The frictional resistance between the two is reduced by the air bearing 23, and the air balance mechanism is balanced by a force commensurate with the weight of the Z-axis spindle 12, so that the Z-axis spindle 12 can move smoothly. Is possible.

[0006]

However, the conventional Z-direction drive mechanism has the following problems. The ball screw shaft 221 and the ball screw nut 222 that apply a driving force to the Z-axis spindle 12 are arranged at a distance from the moving axis of the Z-axis spindle 12. The driving force of the ball screw nut 222 is transmitted to the outer surface of the Z-axis spindle 12 via the coupling member 121. As a result, a torque is generated with respect to the center of gravity of the Z-axis spindle 12 in a direction intersecting with the movement axis of the Z-axis spindle 12, which affects the verticality of the movement of the Z-axis spindle 12. This influence leads to a measurement error when the Z-direction drive mechanism is used in a measuring machine or the like. Further, in order to ensure the verticality of the movement of the Z-axis spindle 12, it is necessary to take special measures such as increasing the rigidity of the guide member 22. Further, since a step of adjusting the ball screw shaft 221 to be provided in parallel with the guide direction of the guide member 22 is required, there is a problem that the number of assembling steps is increased. Another problem was the high noise level of the ball screw.

An object of the present invention is to solve the problems of the prior art, to provide a friction drive device capable of ensuring the verticality of the movement of the lifting member, and to provide a measuring machine with improved measurement accuracy. is there.

[0008]

A friction drive device according to claim 1 is a friction drive device for vertically moving an elevating member guided by guide means up and down, in the vicinity of the center of gravity of the elevating member. And a support shaft arranged substantially parallel to the guide direction of the guide means, at least a pair of rollers provided on the elevating member and sandwiching the support shaft, and a rotation driving means for rotating at least one of the rollers. And is provided.

In such a structure, when at least one of the rollers is rotated by the rotation driving means, the roller is rotated while sandwiching the support shaft. Then, a force that moves upward or downward is generated in the roller due to the frictional force with the support shaft. Since the roller is provided in the elevating member, a force that moves upward or downward is generated in the elevating member together with the roller. Therefore, the elevating member is moved upward or downward while being guided by the guide means. According to the present invention, the force for moving the lifting member is generated between the roller and the support shaft. Since the support shaft is arranged in the vicinity of the center of gravity of the elevating member and substantially parallel to the guide direction of the guide means, the force for moving the elevating member is also the same.
It works in the vicinity of the center of gravity of the elevating member and substantially parallel to the guide direction of the guide means. Conventionally, since the force acting on the elevating member acts on the outer surface of the elevating member, it has not acted on the center of gravity of the elevating member substantially parallel to the guide direction of the guide means. Therefore, a force that intersects the guide direction acts on the elevating member, which may affect the verticality of movement of the elevating member. However, according to the present invention, the force acting on the elevating member acts along the moving axis passing through the center of gravity of the elevating member, so that the elevating member is vertically moved vertically along the guide means to ensure the verticality of the movement. To be done. Further, compared to the drive by the ball screw, the configuration in which the support shaft is sandwiched by the rollers does not require a ball screw nut, so that the friction drive device can be downsized, and the ball screw shaft of the ball screw can be used as a lifting member. The friction drive device of the present invention can be manufactured at low cost, since it is not necessary to adjust the friction drive device so as to be parallel to the movement axis.

A friction drive device according to a second aspect is the friction drive device according to the first aspect, in which one of the support shaft and the elevating member is provided with a piston, and the support shaft and the elevating member are provided. Either of the other is provided with a cylinder chamber that accommodates the piston therein and is capable of relative reciprocal movement in the up-and-down direction with respect to the piston, and by sending air to a chamber defined by the piston in the cylinder chamber, An air balance mechanism for generating a pushing force commensurate with the weight of the elevating member is provided.

According to this structure, a difference in internal pressure occurs between the chamber in which air is fed and the chamber in which air is not fed in the cylinder chamber, and the inner wall of the piston and the inner wall of the cylinder chamber is generated from this difference in internal pressure. A pressing force is generated. The piston and the cylinder are slidable with respect to each other, but the support shaft is not moved in the vertical direction, so that the force pressing the inner wall of the piston and the cylinder chamber substantially acts on the elevating member. By appropriately selecting a chamber into which air is fed among the cylinder chambers defined by the piston, a force can be applied in a direction in which the elevating member is pushed up against gravity. As described above, when the lifting force is applied to the lifting member and the lifting force corresponding to the weight thereof is used to lift the lifting member, the weight of the lifting member is not applied to the roller. Therefore, when the support shaft is sandwiched by the rollers and the lifting member is moved up and down by the frictional force between the roller and the support shaft, the weight of the lifting member does not apply a load to the roller, so the driving force of the roller moves the lifting member. Can be precisely controlled. Further, since it is not necessary to support the weight of the elevating member by the driving force of the roller, the driving force of the roller may be small, and the rotation driving means with small power can be used, which leads to cost reduction.

A friction drive device according to a third aspect of the present invention is the friction drive device according to the first or second aspect, wherein the guide means surrounds the elevating member and guides vertically, and the guide cylinder. And an air bearing mechanism provided between the lifting member and the lifting member.

According to this structure, since the elevating member is guided in the vertical direction by the guide tube of the guide means, the verticality of the movement of the elevating member is ensured. Since the air bearing mechanism is provided between the guide cylinder and the elevating member, friction between the guide cylinder and the elevating member can be reduced, and the elevating member is moved smoothly and with a light force. be able to.

A friction drive device according to a fourth aspect is the friction drive device according to any one of the first to third aspects, wherein the support shaft is swingably provided with an upper end side being a swing fulcrum. It is characterized by

With such a structure, the support shaft can prevent the verticality of the movement of the lifting member from being affected. Since the elevating member is guided by the guide means when the support shaft is fixed, bending stress is applied to the elevating member when the guide direction of the guide means and the direction of the support shaft are deviated. However, according to the present invention, since the support shaft is swingable, the elevating member is moved along the guide direction of the guide means, and the supporting shaft can change its direction flexibly according to the movement of the elevating member. The verticality of movement of the elevating member along the guide direction of the guide means is ensured.

The measuring machine according to claim 5 is the measuring machine according to claims 1 to 4.
The friction drive device described in any one of 1 to 3 is used to configure a moving mechanism that moves a tracing stylus for measuring the position and / or coordinates of a measurement target.

According to this structure, since the measuring machine utilizing the effects of the invention described in claims 1 to 4 can be constructed, the measuring machine can ensure the verticality of the movement of the probe. You can As a result, the measurement accuracy of the measurement using this measuring machine can be improved.

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of a friction drive device and a measuring machine using the same according to the present invention will be described below with reference to the drawings. FIG. 1 is an embodiment in which a friction drive device according to the present invention is used in a coordinate measuring machine 1 as a measuring machine. The coordinate measuring machine 1 is configured to include a base 2 on which an object to be measured is placed and a moving mechanism for moving the tracing stylus 13. As the moving mechanism, a Y for moving the tracing stylus 13 in the Y direction. Direction driving mechanism 3, X-direction driving mechanism 7 for moving the tracing stylus 13 in the X direction, and Z-direction driving mechanism 11 as a friction driving device for moving the tracing stylus 13 in the Z direction.
Is equipped with.

The base 2 is a quadrangular prism having an upper surface that is precision-flattened for mounting an object to be measured. For the sake of explanation, two directions orthogonal to each other on the upper surface of the base 2 are referred to as an X direction and a Y direction, respectively, and a direction perpendicular to the upper surface of the base 2 is referred to as a Z direction. The Y-direction drive mechanism 3 moves on the base 2 in the Y direction.
Direction Y guide rail 4 and a Y slider 5L movably provided along the Y guide rail 4.
And a Y slider 6R that moves in the Y direction on the base 2 in pairs with the Y slider 5L. In addition, the Y guide rail 4 and the Y slider 5L, the base 2 and the Y
An air bearing is provided between the slider 6R and the slider 6R, but the description thereof is omitted.

The X-direction drive mechanism 7 includes a Y slider 5L and a Y slider 5L.
The X-beam 8 which is a longitudinal guide member whose both ends are supported by the slider 6R, the X-slider 9 which is a movable member movably provided along the longitudinal direction of the X-beam 8, and the X-slider 9 are moved. The X slider driving means 10 is provided. The X beam 8 has a long columnar shape, both ends of which are supported on the Y slider 5L and the Y slider 6R.
When the direction slide mechanism 3 is slid in the Y direction, the X beam 8 is also moved in the Y direction. The X slider 9 is slidably provided along the X beam 8. An air bearing is provided between the X slider 9 and the X beam 8, but details thereof will be omitted.

As shown in FIG. 2, the Z-direction drive mechanism 11 includes a Z-axis spindle 12 and the Z-axis spindle 12 as shown in FIG.
Tube 2 as a guide means for vertically guiding the
2 and the upper end is swingably supported and has a piston 29 at the lower end.
The support shaft 28 inserted into the Z-axis spindle 12 so as to pass near the center of gravity of the shaft spindle 12, and the friction drive means 14 provided between the Z-axis spindle 12 and the support shaft 28.
And a housing part 32 for housing them.

The Z-axis spindle 12 is formed in the shape of a long prism, and is vertically guided by a guide cylinder 22. The lower end of the Z-axis spindle 12 is provided with a tracing stylus 13 that comes into contact with the measurement target and measures the position and / or coordinates of the measurement target. Z-axis spindle 12
Friction drive means 14 for driving the Z-axis spindle 12 in the vertical direction is provided at the upper end of the.

As shown in FIG. 3, the friction driving means 14 includes a driving roller 15 and a driven roller 16 which are a pair of rollers sandwiching a support shaft 28, and a driving roller 15.
And a motor 17 for driving the motor. The drive roller 15 and the driven roller 16 sandwich the support shaft 28 with a predetermined pressing force, and the frictional force generated between the rollers 15 and 16 does not cause the rollers 15 and 16 to idle with respect to the support shaft 28. It is composed. The drive roller 15 and the motor 17 are provided with pulleys 151 and 171, respectively, and the belt 1 wound around the pulleys 151 and 171.
The power of the motor 17 is transmitted to the drive roller 15 via 8.

An air balance mechanism 19 is provided inside the Z-axis spindle 12. This air balance mechanism 1
9 is a cylinder chamber 20 provided in the Z-axis spindle 12.
And a piston 29 of the support shaft 28, and air is supplied to one chamber 201 of the cylinder chamber 20. A cylinder chamber 20 is provided along the axis of the Z-axis spindle 12 so as to pass through the center of gravity of the Z-axis spindle 12. A piston 29 provided at the lower end of a support shaft 28 is slidably inserted into the cylinder chamber 20. In the chamber 201 on the support shaft side of the cylinder chamber 20 defined by the piston 29, the fumarole 2 for supplying air to the chamber 201 is provided.
1 is provided. The air is supplied with a pressure to generate a pushing force commensurate with the weight of the Z-axis spindle 12 by the internal pressure of the chamber 201 on the support shaft side of the cylinder chamber 20.

The guide cylinder 22 is provided on the X slider 9 with its cylinder hole oriented vertically, and the Z-axis spindle 12 is inserted through the guide cylinder 22 so as to be vertically movable. An air bearing 23 is provided between the guide cylinder 22 and the Z-axis spindle 12. Air bearing 23
Is provided with the air pad 24 in the tube hole of the guide tube 22,
It is formed by ejecting air from the air pad 24 to the sliding surface of the Z-axis spindle 12.

The support shaft 28 is supported at its upper end by a column 25 standing on the guide cylinder 22. The column 25 has a horizontal beam 26 at a position having a height equal to or greater than the amount of movement of the Z-axis spindle 12 from the guide cylinder 22, and a hole is provided at the intersection of the horizontal beam 26 and the movement axis of the Z-axis spindle 12. . A flange portion 30 having a surface orthogonal to the support shaft 28 is provided at the upper end of the support shaft 28, and a ball 31 is provided above the flange portion 30. The support shaft 28 is inserted through the hole of the lateral beam 26, and the ball 31 of the support shaft 28 is rotatably supported by being supported by the bearing piece 27 provided on the support column. The piston 29 is provided at the lower end of the support shaft 28 as described above, and is inserted into the cylinder chamber 20 of the Z-axis spindle 12.

The housing portion 32 is provided on the X slider 9 so as to cover the support column 25 from the guide cylinder 22.

In the coordinate measuring machine 1 having such a structure, when measuring the position and / or coordinates of the measurement object, the measurement object is placed on the base 2 and the Y-direction drive mechanism 3, The X-direction drive mechanism 7 is driven to move the tracing stylus 13 to bring the tracing stylus 13 into contact with the object to be measured. By recording the position of the tracing stylus 13 at this time, the position and / or coordinates of the measuring object can be measured.

When the Z-direction drive mechanism 11 is driven,
The motor 17 is rotationally driven to rotate the drive roller 15. Then, since the support shaft 28 is sandwiched between the driving roller 15 and the driven roller 16, both the rollers 15, 1
The drive roller 15 and the driven roller 16 are moved along the support shaft 28 by the frictional force between the support shaft 28 and the support shaft 28. When the drive roller 15 and the driven roller 16 are moved, the Z-axis spindle 12 is moved by the guide cylinder 22 together with the rollers 15 and 16.
The stylus 13 is moved up and down while being guided by.

Therefore, the present embodiment has the following effects. The force that moves the Z-axis spindle 12 is the force applied to both rollers 1.
It occurs between 5, 16 and the support shaft 28. Support shaft 28 is Z
Since it is inserted into the cylinder chamber 20 passing through the position of the center of gravity of the shaft spindle 12, the action of the force for moving the Z axis spindle 12 also acts along the axis passing near the position of the center of gravity of the Z axis spindle 12. Conventionally, Z-axis spindle 12
Since the force that acts on the Z-axis spindle 12 acts on the outer surface of the Z-axis spindle 12, it does not act on the center of gravity of the Z-axis spindle 12 substantially parallel to the guide direction of the guide cylinder 22. Therefore, a force that intersects the guide direction acts on the Z-axis spindle 12, and the verticality of the movement of the Z-axis spindle 12 may be affected. However, according to the present embodiment, since the force acting on the Z-axis spindle 12 acts along the moving axis passing through the center of gravity of the Z-axis spindle 12,
The Z-axis spindle 12 is vertically moved vertically along the guide tube 22 to ensure the verticality of the movement. As a result, the verticality of the movement of the tracing stylus 13 is also ensured, and the measurement accuracy of the coordinate measuring machine 1 is improved.

A support shaft side chamber 201 defined by a piston 29 of a cylinder chamber 20 provided in the Z-axis spindle 12.
Is supplied to the Z-axis spindle 12.
Since a push-up force commensurate with the weight of
The Z-axis spindle 12 bears little weight on 16. Therefore, the Z-axis spindle 12 is attached to both rollers 15 and 16.
Since the weight of the Z-axis spindle 12 is not applied, the movement of the Z-axis spindle 12 can be precisely controlled. In addition, both rollers 15, 16
Since it is not necessary to support the weight of the Z-axis spindle 12 with the driving force of 1, the driving force of both rollers 15, 16 may be small.
That is, the drive roller 15 and the driven roller 16 are connected to the support shaft 28.
It is sufficient that the force for pinching is a frictional force between the support shaft 28 and the rollers 15 and 16, and the motor 17 having a small driving force can be used, which leads to cost reduction.

Since the air bearing 23 is provided between the guide cylinder 22 and the Z-axis spindle 12, the friction between the guide cylinder 22 and the Z-axis spindle 12 can be reduced, and the Z-axis spindle 12 can be prevented. It can be moved smoothly and with a light force. Therefore, the movement of the Z-axis spindle 12 can be precisely controlled, and the measurement accuracy of the coordinate measuring machine 1 can be improved.

Since the support shaft 28 is swingably supported at its upper end, the Z-axis spindle 1 guided by the guide cylinder 22 is supported.
According to the movement of 2, the support shaft 28 can change its direction flexibly. Therefore, the support shaft 28 does not affect the verticality of movement of the Z-axis spindle 12, and the Z-axis spindle 1
The verticality of the movement of 2 is secured. As a result, the probe 13
Since the verticality of the movement is ensured, the measurement accuracy of the coordinate measuring machine 1 is improved.

Further, conventionally, it was necessary to provide a ball screw shaft of a ball screw or the like in order to drive the Z-axis spindle 12, so a space for that was required, but in the present embodiment, a support is provided. Shaft 28 with both rollers 1
Since it is only sandwiched between 5 and 16, the Z-direction drive mechanism 11 can be downsized, and the coordinate measuring machine 1 can be downsized. Furthermore, since the Z-direction drive mechanism 11 is downsized, the required strength of the X-direction drive mechanism 7 and the Y-direction drive mechanism 3 can be reduced, so the coordinate measuring machine 1
Can be downsized and the cost can be reduced.

The friction drive device of the present invention is not limited to the above-mentioned embodiment, and it goes without saying that various modifications can be made without departing from the scope of the present invention. For example, as shown in FIG. 4, the air balance mechanism 19 may not be provided. That is, without providing the cylinder chamber 20 in the Z-axis spindle 12 and the piston 29 in the support shaft 28, the support shaft 28 is provided along the vertical axis passing near the center of gravity of the Z-axis spindle 12 in the Z-axis spindle 12. It may be inserted. Even with this configuration, Z
The force to move the axis spindle 12 is the Z axis spindle 1
Since it acts along the guide direction passing near the position of the center of gravity of 2, the verticality of the movement of the Z-axis spindle 12 is secured.

Conventionally, since the driving force generated by a ball screw or the like acts on the outer surface of the Z-axis spindle, unless the weight of the Z-axis spindle is supported by the air balance mechanism 19, a large bending stress is applied to the Z-axis spindle. It was structured. However, in the present embodiment in which the support shaft that passes near the center of gravity of the Z-axis spindle is sandwiched by the rollers, the weight of the Z-axis spindle can be supported by the support shaft.
Therefore, even if the air balance mechanism is removed, bending stress is not applied to the Z-axis spindle, and the verticality of movement of the Z-axis spindle is ensured. As a result, the manufacturing cost can be reduced as much as the air balance mechanism is eliminated.

In the present embodiment, the two rollers sandwiching the support shaft 28 are the driving roller 15 and the driven roller 16, but it goes without saying that three or more rollers may be provided. Further, the number of rollers driven by the motor 17 may be two or more instead of one. In the air balance mechanism 19 of the present embodiment, the cylinder chamber 20 is provided in the Z-axis spindle 12 and the piston 29 is provided in the support shaft 28. However, the piston 29 is provided in the Z-axis spindle 12 and the support shaft 28 is provided in the support shaft 28. The cylinder chamber 20 may be provided. In the present embodiment, an example in which the friction drive device is applied to the coordinate measuring machine 1 has been shown, but the friction drive device of the present invention is not limited to the coordinate measuring machine 1 and various applications are conceivable. For example, it can be applied not only to one-dimensional measuring machines (height gauges) and two-dimensional measuring machines (surface roughness measuring machines) but also to various machine tools for precision machining.

[0038]

As described above, according to the friction drive device of the present invention, the friction drive device for ensuring the verticality of the movement of the elevating member is provided, and at the same time, the measuring machine with improved measurement accuracy is provided. It is possible to exert an excellent effect of being able to.

[Brief description of drawings]

FIG. 1 is a diagram showing a coordinate measuring machine using a friction drive device according to an embodiment of the present invention.

FIG. 2 is a sectional view of a Z-direction drive mechanism in the embodiment.

FIG. 3 is an enlarged view of the friction drive means seen from above in the embodiment.

FIG. 4 is a sectional view of a Z-direction drive mechanism that does not use an air balance mechanism in the embodiment.

FIG. 5 is a diagram showing a conventional Z-direction drive mechanism.

[Explanation of symbols]

1 three-dimensional measuring machine (measuring machine) 11 Z-direction drive mechanism (friction drive device) 12 Z-axis spindle (elevating member) 13 probe 15 Drive roller 16 Driven roller 17 motor 19 Air balance mechanism 20 cylinder chamber 22 Guide tube (guide means) 28 Support shaft 29 pistons 201 Support shaft side chamber

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Ayako Kimatsu             2200 Shimoguricho, Utsunomiya City, Tochigi Prefecture             Within Mitutoyo (72) Inventor Seiichi Otsubo             2200 Shimoguricho, Utsunomiya City, Tochigi Prefecture             Within Mitutoyo F term (reference) 2F069 AA04 DD27 GG01 GG62 HH01                       JJ08 MM33                 3J062 AA60 AB21 AC07 BA11 BA14                       CC12 CC21 CC31

Claims (5)

[Claims] 1. A friction drive device for vertically moving an elevating member guided by guide means in a vertical direction, the friction drive device being disposed in the vicinity of the center of gravity of the elevating member and substantially parallel to the guide direction of the guide means. A friction drive device, comprising: a support shaft; at least a pair of rollers provided on the elevating member and sandwiching the support shaft; and a rotation drive unit that rotates at least one of the rollers. 2. The friction drive device according to claim 1, wherein a piston is provided on one of the support shaft and the elevating member, and the other of the support shaft and the elevating member is internally provided with the piston. A cylinder chamber for accommodating the piston and capable of reciprocating vertically relative to the piston is provided, and by pushing air into the chamber of the cylinder chamber defined by the piston, a pushing force commensurate with the weight of the lifting member. A friction drive device characterized by being provided with an air balance mechanism for generating. 3. The friction drive device according to claim 1, wherein the guide means is provided between a guide cylinder that surrounds the elevating member and guides in a vertical direction, and between the guide cylinder and the elevating member. And a friction drive device including the air bearing mechanism. 4. The friction drive device according to claim 1, wherein the support shaft is swingably provided with an upper end side as a swing fulcrum. 5. A moving mechanism for moving a tracing stylus for measuring the position and / or coordinates of an object to be measured by using the friction drive device according to any one of claims 1 to 4. Measuring machine characterized by.