JPH0351513A - Rectilinear guide - Google Patents

Abstract

PURPOSE:To reduce the frictional force, to simplify the mechanism and to reduce the size by finishing the opposite surfaces of a vibration member and a movable member to be smooth, and providing a linear groove on one member and a linear projecting portion on other member. CONSTITUTION:A vibration member 1 fixed to a fixed member 3 and a movable member 2 are disposed opposite to each other in the direction of Z. The opposite surfaces of the vibration member 1 and the movable member 2 are finished to be smooth. A groove 4 and a projecting portion 5 are provided in such a manner that the longitudinal directions are aligned with the moving direction (X-direction) of the movable member 2 and both are opposite to each other. The projecting portion 5 is engaged with the groove 4, and a very small gap is formed between the side surfaces thereof so as to form a squeeze air film. Thus, a small-sized linear guide which has small frictional force and is simple in mechanism can be attained.

Description

[Detailed description of the invention] [Industrial application fields] The present invention relates to a linear guide for a positioning mechanism and the like.

[Prior Art] In guide mechanisms that perform mechanical relative linear motion, various means, such as non-contact mechanisms such as hydrostatic gas bearings and magnetic bearings, are used to reduce or eliminate frictional forces between parts. It is used.

[Problem to be solved by the invention] With the recent trend of miniaturization of mechanical parts,
When trying to construct a guide mechanism with a size of 710 mm,
Since the above-described non-contact mechanism requires a plurality of nozzles and electromagnets as essential components, it is almost impossible to manufacture a small one, or it may be expensive. Repulsive levitation using permanent magnets is also considered, but this requires support in either direction with control force or gas pressure, and has similar drawbacks.

At present, the superconducting repulsion type non-contact mechanism that utilizes the Meissner effect requires preparation to keep the cooling equipment and mechanism at a low temperature, and it will take many years before it is widely put into practical use.

An object of the present invention is to provide a compact linear guide.

[Means for Solving the Problems] A first linear guide of the present invention includes a vibrating member whose part is fixed, and a movable member provided facing one vibrating surface of the vibrating member. The facing surfaces of the vibrating member and the movable member are finished smooth, and the linear grooves on one side and the linear protrusions on the other side are arranged so that their longitudinal directions coincide with the moving direction of the movable member and face each other. The protrusion fits into the groove.

The second linear guide of the present invention includes two vibrating members that are partially fixed to each other and whose vibrating surfaces face each other, and is arranged with a small gap between the two vibrating members and the vibrating member. Both vibrating surfaces and the surface of the movable member facing each other are finished smooth, and either one of the vibrating members and the surface of the movable member facing each other, or both of the vibrating member and the movable member have a smooth finish. The opposing surfaces are provided with a linear groove on one side and a linear protrusion on the other side so that the longitudinal direction coincides with the direction of movement of the movable member and are opposed to each other, and the protrusion fits into the groove. It matches.

[Function] The invention utilizes the squeeze effect in which when a smooth surface is vibrated at high frequency, a pressure higher than the ambient pressure is generated in a minute gas film between the same smooth surface and the opposing smooth surface. A vibrating member is installed on the fixed side, and grooves and convex portions are provided on both opposing surfaces of the vibrating member and the movable member so that their longitudinal directions coincide with the moving direction of the movable member so that they face each other, thereby restraining the movable member in a direction perpendicular to the moving direction. The movable member is supported by the squeeze gas film without contacting the vibrating member.

The vibrating member is formed of a plate of piezoelectric material or the like, or a silicon film facing an electrode for generating electrostatic force.

Therefore, the present linear guide can be made into a microscopic shape, and a low-friction linear guide based on so-called micromechanics and micromechatronics can be realized.

Here, the principle of a squeeze bearing using the squeeze effect will be explained with reference to FIG.

The movable member 3 and the vibrating member 32 are arranged with a small gap (squeezed gas film) 33 maintained therebetween, and the mutually opposing surfaces of both members 31 and 32 are finished smooth. Vibration member 3
When 2 is vibrated at high frequency, the movable member 31 and the vibrating member 32
Since the facing surface of the squeeze gas film 33 has a smooth finish, the gas has viscosity in the vicinity of the squeeze gas film 33 with a small gap, so its inflow and outflow is restricted, and the movable member 31 cannot follow the movement due to inertia, causing almost no vibration. Instead, it is the same as if a high-frequency volume change were caused in a sealed compressible fluid.

In this case, the pressure generation with respect to displacement becomes non-linear, and a squeezed gas film 33 having a pressure higher than the ambient pressure on a time average forms. As a result, the movable member 31 is supported on the vibrating member 32 without contact. This phenomenon is known as the compressible squeeze gas film effect.

[Example] Next, an example of the present invention will be described with reference to the drawings.

FIG. 1 is a perspective view of a linear guide according to a first embodiment of the present invention, and FIG. 2 is a side view in the X direction of FIG.

A vibrating member 1 fixed to a fixed member 3, consisting of a vibrating piece 1a made of a piezoelectric material, an electrode 1b for vibrating the vibrating piece 1a, and a vibration transmitting piece 1c to which the vibration of the vibrating piece 1a is transmitted; Movable members 2 are arranged facing each other in two directions. The opposing surfaces of the vibrating member 1 and the movable member 2 are finished smooth, and the grooves 4 and the convex portions are arranged so that the longitudinal direction coincides with the moving direction (X direction) of the movable member 2 and are opposed to each other. 5 are respectively provided, and the convex portions 5 fit into the grooves 4, and as shown in FIG. 2, a minute gap is formed between the side surfaces 4a and 5a, which is large enough to form a squeeze gas film. Here, the material constituting the vibration transmission piece 1c and the movable member 2 is not particularly limited to a piezoelectric material, as long as it is capable of forming grooves 4 or convex portions 5 on its surface. Furthermore, even if piezoelectric materials are used for the vibration transmission piece 1c and the movable member 2, the grooves 4 and the convex portions 5 can be formed by forming a silicon film on the surface using lithographic techniques common in the semiconductor industry. , Since minute objects can be realized, the guide mechanism can be made compact. in this case,
Although the mechanism for driving the movable member 2 in the moving direction (X direction) is not shown, electrostatic force, electromagnetic force, etc. can be used. Furthermore, a positioning mechanism can be constructed by incorporating a displacement sensor. Note that the groove 4 is connected to the movable member 2,
Of course, the convex portion 5 may be formed on the vibrating member 1.

Next, the operation of the first embodiment will be explained using FIGS. 2 and 3. A high frequency voltage is applied between the electrodes lb and the vibrating piece 1a
When vibrated, the vibration is transmitted to the vibration transmission piece 1c, and the vibrating member 1 vibrates as a whole, and as a result, a squeeze gas film 6 is formed between it and the movable member 2. Its thickness is determined by the vibration amplitude of the vibrating piece 1a, the weight of the movable member 2, and the smoothness of the surfaces of the movable member 2 and the vibration transmitting piece IC, and μ
It is of the order of m. For movement in the Y direction, groove 4, protrusion 5
are combined as shown in Figure 2, so they are constrained. The contact force between the side surface 4a of the groove 4 and the side surface 5a of the convex portion 5 is small because it is in the horizontal direction, and there is also the effect of the vibration of the vibrating member 1, so even if they are in contact with each other, there is no movement in the X direction. The frictional force against is small. The vibration direction of the vibrating member 1 is 2
However, when the frequency is high, as is well known, there is also a component perpendicular to this direction, so it is thought that a positive pressure film is also generated between the side surfaces 4a and 5a due to the squeeze effect. As a result, it can be expected that the resistance force in the moving direction X will become smaller.

FIG. 3 is a diagram for explaining straight-ahead guidance according to the second embodiment of the present invention.

In this embodiment, a vibrating member 11 made of a silicon film is arranged facing an electrode 12 for generating electrostatic force, and is fixed to a fixed member 13 (movable members, grooves, and convex portions are not shown). Direction perpendicular to the moving direction of the member (Y direction in Figure 1)
FIG. The operation and effects are similar to those of the first embodiment.

FIG. 4 is a diagram for explaining straight-ahead guidance according to the third embodiment of the present invention.

In this embodiment, a vibrating piece 21a, an electrode 21b, a vibration transmitting piece 2
1c, a vibrating member 21 partially fixed to a fixed member 23, a vibrating piece 22a, an electrode 22b, and a vibration transmitting piece 22.
An example (groove,
FIG. 4 is a side view of the movable member 25 (a convex portion is not shown) as seen from a direction perpendicular to the moving direction of the movable member 25. With this configuration, in addition to the effects of the first and second embodiments, the installation direction of the mechanism relative to the direction of gravity can be made freely.

In this case, the grooves or convex portions are the opposing vibration transmission pieces 21c, 2.
It may be formed on one or both surfaces of the movable member 2c, or a convex portion or a groove may be formed on one or both surfaces of the movable member 25 accordingly.

Note that in the first to third embodiments, the vibration members 1, 11
, 21, and 22 are configured to be supported and fixed from one side, but it goes without saying that they may be configured to be supported and fixed from both sides.

[Effects of the Invention] As explained above, the present invention makes it possible to realize a compact linear guide with low frictional force and a simple mechanism by utilizing the squeeze gas film, the groove, and the convex part. The energy source for this is an electric circuit, which has superior reliability and maintainability compared to compressors or gas cylinders that use hydrostatic air bearings.

[Brief explanation of drawings]

FIG. 1 is a perspective view of the straight guide according to the first embodiment of the present invention, FIG. 2 is a side view in the X direction of FIG. 1, and FIGS. A diagram showing a straight line guide in an embodiment of
FIG. 5 is a diagram showing the principle of a squeeze bearing. 1,1 1,21.22-... Vibration member la, 21a,
22a=vibration piece lb, 21b, 22b--electrode lc, 21c, 22c...vibration transmission piece 2.25--
Movable members 3, 13, 23, 24--Fixed member 4...Groove 4 a-Side surface 5 of groove 4...Convex portion 5a...Side surface 6 of convex portion 5...Squeeze gas film

Claims (1)

[Claims] 1. A vibrating member whose part is fixed, and a movable member provided opposite to one vibrating surface of the vibrating member, and an opposing surface between the vibrating member and the movable member. are finished smoothly, and have a linear groove on one side and a linear protrusion on the other side so that the longitudinal direction coincides with the moving direction of the movable member and are opposed to each other, and the protrusion is A linear guide that fits into the groove and has a minute gap formed between the groove and the convex portion. 2. It has two vibrating members that are partially fixed to each other and whose vibrating surfaces face each other, and a movable member that is arranged between the two vibrating members with a small gap from the vibrating member, Both of the vibrating surfaces and the movable member facing thereto are finished smoothly, and one of the vibrating members and the movable member face each other, or both the vibrating member and the movable member face each other. A linear groove is provided on one side of the surface, and a linear convex portion is provided on the other side so that the longitudinal direction coincides with the moving direction of the movable member and faces each other, and the convex portion is provided in the groove. A linear guide that fits together and has a minute gap formed between the groove and the convex portion.