JPS60238702A - Three-dimensional measuring machine - Google Patents

Abstract

PURPOSE:To execute a measurement with high accuracy even in case of a large- sized device, and to reduce the accuracy drop in the X direction by forming a lng part so that it is scarcely inclined and also scarcely displaced in the direction (X direction) for connecting both leg parts, with regard to an air bearing device provided on a lower end supporting part of one leg part. CONSTITUTION:A guide member 41 whose section is a square is formed by an upper end horizontal guide surface 41A and both sides vertical guide surfaces 41B having an angle relation of a right angle each other. Also, this machine has an air jet surface 43A and 43B opposed to each guide surface 41A and 41B, respectively, and it is provided with a lower end supporting part 43 guided by the guide member 41. Accordingly, one leg part 6 provided vertically on the lower end supporting part 43 is supported so that it is scarcely inclined and also scarcely displaced in the X direction. In this way, the accuracy drop in the X direction is reduced, and especially, even in case when the whole device is large in size and heavy in weight, a measurement is executed with high accuracy, and also the surface of an object placing plate can be used widely.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a three-dimensional measuring machine, and particularly relates to a three-dimensional measuring machine that generates a detection signal by relating to the object to be measured on a mounting table on which the object to be measured is placed. This invention relates to improvements in a moving mechanism for moving a detector in three dimensions.

[Background technology and problems thereof] A detector such as a touch signal probe is supported so as to be movable in three-dimensional directions by a moving mechanism, and the detector is moved while engaging the object to be measured on a stage. The amount of displacement is detected in each axis direction, and these detected values are processed to measure the object to be measured.
Coordinate measuring machines that perform inspections, etc. are known and used in a wide range of fields, but one of the moving mechanisms of such three-dimensional measuring machines is a so-called circular three-dimensional measuring machine equipped with a gate-shaped support. There is a chance.

FIG. 1 shows a conventional circular three-dimensional measuring machine. In the figure, the upper end surface of the stage l is finished extremely smooth, and the object to be measured (not shown) is placed on it. At the same time, the moving mechanism 2
A detector 3 such as a touch signal probe is supported so as to be movable in three dimensions. The moving mechanism 2 includes a circular support 4 arranged to straddle the object to be measured on the stage l, and this circular support 4 has legs 5.6 arranged on both sides of the stage l. An X-axis slider 8 is supported movably along the It is detected by an X-direction scale 7A attached along the section 7. In addition, the X-axis slider 8 has a Z
An axis slider 9 is supported movably along the Z direction, and the detector 3 is attached to the lower end of the Z axis slider 9. Furthermore, one of the legs 5.6 is freely movable on the stage l, and the other leg 6 is guided by a guide rail ii along the Y direction, thereby forming a circular shape. The support column 4 is placed on the stage l so as to be able to reciprocate along the Y direction.The lower end portions of each of the legs 5.6 are connected to a long lower end support portion 12.13 along the Y direction. It has been done, ゛・
Even while the circular support 4 is moving in the Y direction, its standing state is stably maintained. In addition, Y of the circular support 4
The amount of displacement in this direction and the amount of displacement of the Z-axis slider 9 in the Z-axis direction are also detected by Y-direction and Z-direction scales (not shown), respectively.

Air bearing devices 15 are provided at both longitudinal ends of the lower end support portion 12, and the air bearing devices 15 include an air pad 16 that is a separate member from the lower end support portion 12, as shown in FIGS. , a mounting member 17, and a connection nozzle 18 as an air supply connector. The air pad 16 has a mounting surface 1 attached to the lower end support portion 12.
A circular recess 21 is provided in the center of the support plate 9, and a plurality of air jet holes 23 with extremely small diameters (for example, about 0.2 m layer or less) are arranged in a pattern on the air jet surface 22 facing the stage l. Further, a connecting space 24 communicating with these air jetting holes 23 is provided inside, and air is introduced into each connecting space 24 from a connecting nozzle 18 to each air jetting hole 23 through the connecting space 24. Compressed air is supplied. Note that the distribution density of the air jet holes 23 is actually much denser than expressed in the drawing.

On the other hand, the mounting member 17 is mounted in the recess 21 of the air pad 16, and has a conical engagement groove 28 formed in the center of its upper surface to support a pole 27 interposed between the mounting member 17 and the lower end support 12. has been done.

Further, in the lower end support section 13, an air bearing device 15 having a similar structure is provided between the upper end horizontal guide surface 11A and both side vertical guide surfaces 11B of the guide rail 11, as shown in FIG. Furthermore, similar to the case of the lower end support section 12, such air bearing devices 15 are also provided at both ends of the lower end support section 13 in the longitudinal direction.

However, such a conventional structure has the following problems.

That is, conventionally, the air jetting surface 22 of the air pad 16 and the guide surface (loading table L, upper end horizontal guide surface 11A of the guide rail 11)
The air pad 16 is rotated and adjusted via the pole 27 because it would be difficult to manufacture and would be a heavy economic burden to maintain the parallelism with the vertical guide surfaces 11B). The aim was to absorb manufacturing errors by pivoting the parts as much as possible. Therefore, if bending occurs in the folding part 7 due to the overall load weight of the folding part 7 including the X-axis slider 8 or a change in load (W) due to the movement of the X-axis slider 8 on the folding part 7, the folding part 7 and both legs 5
．． 6 can be seen as a rigid frame structure, and as shown in FIG. 6, both legs 5 and 6 were slanted. As a result, the X-direction scale 7A was displaced in the detection direction (X-direction) by the value indicated by the text in the figure, resulting in a decrease in measurement accuracy in the X-direction.

This situation is becoming more and more noticeable as the entire device, including the folding section 7 and the X-axis slider 8, becomes larger and heavier as the object to be measured becomes larger and the automatic side and fixed functions are added. Therefore, this cannot be ignored in ensuring high precision measurement.

[Objective of the Invention 1 The object of the present invention is to reduce the decrease in accuracy in the X direction, and in particular, to
To provide a three-dimensional measuring machine capable of highly accurate measurement even when the entire device is large and heavy.

[Means and actions for solving the problem J Therefore,
The present invention provides an air bearing device provided at the lower end support portion of one leg of a portal support so as to allow the leg to move freely on the stage, and the air bearing device provided at the lower end support portion of the other leg. The air bearing device provided on the leg is formed to make it difficult to tilt the leg and to make it difficult to displace in the direction (width direction) connecting both legs, thereby making it difficult to tilt and displace the other leg in the width direction. This prevents the X-direction scale attached to the phase part of the circular column from shifting, and also allows the one leg to move freely to prevent excessive strain on the overall structure of the gate-shaped column. The aim is to achieve the above objective by avoiding

[Example] Hereinafter, an example of the present invention will be described based on the drawings, and the same parts as the above-mentioned conventional structure will be given the same reference numerals and the explanation will be omitted.

FIG. 7 shows an embodiment of the three-dimensional measuring machine according to the present invention. In this figure, the lower end support part 12 of one of the legs 5, 6 is constructed in the same manner as the conventional structure, but the guide member The lower end support member 43 guided at 41 has a configuration as shown in FIG. That is, the guide member 41
has a rectangular cross section, and has an upper horizontal guide surface 41A and both vertical guide surfaces 41B, and these guide surfaces 41A and 41B have an angular relationship that is perpendicular to each other. The lower end support portion 43 guided by the guide member 41 has air jet surfaces 43A and 43 facing each of the guide surfaces 41A and 41B, respectively.
B, so that the other leg 6 implanted in the lower end support part 43 is difficult to tilt and both legs 5 and 6 are
It is said that displacement in the direction connecting the two (in the width direction) is difficult. Each air jetting surface 43A, 43B has a plurality of air jetting holes 2, respectively.
3 are arranged in a matrix pattern, and these air ejection holes 23 are connected to an external air supply source through a connection space 24 and a connection nozzle 18, and the air pressure ejected from each air ejection hole 23 causes A lower end support portion 43 is slidably guided along the guide member 41. Here, an air bearing device 55 is constituted by each air ejection surface 41A, 41B having the air ejection hole 23, the external air supply source, and the like.

Note that the distribution density of the air jet holes 23 is actually much higher than that shown in the drawing.

According to this embodiment, the lower end support member 12 is freely movable on the stage l via the air bearing device 15'+, while the other lower end support member 43 is moved by the air bearing device 55. Since the leg part 6 is difficult to tilt and difficult to displace in the direction connecting both the leg parts 5 and 6 (X direction), the portal support 14
The displacement of the X-direction scale 7A in the X-direction, which occurs due to the heavy weight of the structure and changes in load due to the movement of the X-axis slider 8, is suppressed to the utmost. That is, by firmly maintaining the upright state of the leg portion 6 by the air bearing device 55 provided on the lower end support portion 43, the displacement of the X-direction scale 7A provided on the phase portion 4 is prevented as much as possible. .

Therefore, due to the recent increase in the size of objects to be measured, the circular support 4
When increasing the height of the X-axis slider 8, etc. or increasing the weight of the X-axis slider 8 due to automatic measurement, conventionally, the X-direction scale 7 was required to ensure high precision measurement.
In contrast to this, in this embodiment, even in such a case, the above-mentioned positional deviation of the X-direction scale 7A can be prevented as much as possible to ensure highly accurate measurement.

In the above embodiment, the air jet surfaces 43A and 43B were formed directly on the lower end support part 43, but as shown in FIG. is fixed to the lower end support part 43,
Regarding the portion facing the vertical guide surfaces 41B on both sides, air pads 16 of the conventional structure are attached to the lower end support portion 43 via poles 27, thereby making it difficult to displace and tilt the leg portion 6 in the X direction. It may be.

Further, as shown in FIG. 10, the upper horizontal guide surface 41
A total of two air pads 16 for the air pad 16 facing A and the air pad 16 facing one of the two vertical guide surfaces 41B may be fixedly provided on the lower end support portion 43. Furthermore, as shown in FIG. 11, the air butt fixedly provided on the lower end support portion 43 is not limited to the case where only one wide air butt is provided.
The legs 6 are made by arranging a plurality of narrow air pads 56, etc.
Alternatively, instead of forming the air ejection holes 23 individually, the portions constituting the air ejection surfaces 22.43A and 43B may be made of porous material. It is also possible to incorporate the body.

[Effects of the Invention] As described above, according to the present invention, it is possible to reduce the decrease in accuracy in the X direction, and in particular, to perform three-dimensional measurement that allows highly accurate measurement even when the entire device is large and heavy. We can provide equipment.

[Brief explanation of the drawing]

Figure 1 is a perspective view showing the overall configuration of a conventional coordinate measuring machine.
2, 3, and 4 are a partially cutaway plan view, front view, and bottom view of an air bearing device of a conventional coordinate measuring machine, respectively, and FIG. 5 is a guide member of the conventional example. FIG. 6 is a front view showing the positional deviation of the scale in the X direction in the conventional example, and FIG. 7 shows the overall configuration of an embodiment of the coordinate measuring machine according to the present invention. Fig. 8 is an enlarged side view of the main part, Fig. 9, Fig. 1θ,
and FIG. 11 are front views showing different embodiments other than the above. l... Load stage, 2... Moving mechanism, 3... Detector,
4...Portal support, 5, 6...Leg, 7...Surgery area,
12.43...Lower end support part, 2″2, 43A, 43B
...Air blowout surface, 23...Air blowout hole, 41...
Guide member, 41A... Upper end horizontal guide surface, 41B...
Vertical guide surfaces on both sides, 55...Air bearing device. Figure 1 Figure 5 Figure 6 Figure 7 Figure 8 □-11 Figure 10 Figure 11

Claims (1)

[Claims] (1) A moving mechanism that moves a detector that interacts with the object to be measured and generates a detection signal in a three-dimensional direction with respect to the workpiece on which the object to be measured is placed. It is configured to include a gate-shaped support arranged to straddle the support, and the circular support can reciprocate in a predetermined direction on the document table via an air bearing device provided at the lower end support of both legs. In the guided coordinate measuring machine, the air bearing device provided at the lower end support of the one leg is formed to allow the leg to move freely on the stage, and the air bearing device is configured to allow the leg to move freely on the stage. A three-dimensional measuring machine, characterized in that the air bearing device provided on the lower end support part is formed so as to make it difficult to tilt the leg part and to make it difficult to displace the leg part in a direction connecting both the leg parts. (2. In Claim 1, the air bearing device provided at the lower end support portion of the other leg is connected to the upper end horizontal guide surface of the guide member having a rectangular cross section provided on the IR stage. It has an air ejection surface provided opposite to each of the vertical guide surfaces on both sides, and at least one air ejection surface among these air ejection surfaces is fixedly provided on the lower end support part. Features・3D measuring machine.