JP2021043219A - Three-dimensional-coordinate-measuring device - Google Patents

Abstract

To provide a three-dimensional-coordinate-measuring device capable of improving accuracy of measurement.SOLUTION: The three-dimensional-coordinate-measuring device comprises: a stool 10 on which a measurement object is placed; a Y carriage 16 having a first support member having a drive mechanism for driving the Y carriage in a Y-axis direction and a second support member that moves following the first support member; a Y guide 42 integrally formed with the stool in parallel to the Y-axis direction; a first both side support unit 50 for sandwiching both side faces of the Y guide and guiding movement of the first support member in the Y-axis direction; and a scale for measuring a position of the Y carriage moving in the Y-axis direction. The Y guide is formed on the stool, with a groove 40 formed on a top face 10T of the stool as a border, and when an area on the top face of the stool where the measurement object is placed is defined as a measurement area, the scale is provided on a side face of the groove on the measurement area side of an inner face of the groove.SELECTED DRAWING: Figure 3

Description

The present invention relates to a three-dimensional coordinate measuring device, and more particularly to a three-dimensional coordinate measuring device that measures a three-dimensional shape of a measurement object by moving a measuring probe in the three-axis directions of the X, Y, and Z axes.

In a general three-dimensional coordinate measuring device, a Y carriage that is movable in the front-rear direction (Y-axis direction) is arranged on the upper part of a surface plate on which a measurement object is placed. The Y carriage has a columnar X guide spanned along the left-right direction (X-axis direction), and the X-carriage is movably supported by the X guide in the X-axis direction. A columnar Z-carriage along the vertical direction (Z-axis direction) is movably supported in the X-carriage in the Z-axis direction, and a measurement probe is attached to the lower end of the Z-carriage. As a result, the stylus of the measuring probe is movably supported in the three axial directions of the X, Y, and Z axes.

In such a three-dimensional coordinate measuring device, Patent Document 1 discloses a support structure in which a Y carriage is supported on both left and right side surfaces of a surface plate and an upper surface of the surface plate via an air pad (air bearing).

JP-A-2007-33052

By the way, in a three-dimensional coordinate measuring device whose speed and accuracy are increasing, it is indispensable to increase the rigidity of the Y carriage.

However, in Patent Document 1, since the air pad for suppressing the upward movement of the Y carriage is not provided, the Y carriage may fluctuate in the X-axis direction (pitching direction), which may lead to a decrease in measurement accuracy. There was sex.

The present invention has been made in view of such circumstances, and an object of the present invention is to provide a three-dimensional coordinate measuring device capable of suppressing runout of the Y carriage in the pitching direction and improving measurement accuracy. And.

In order to achieve the above object, the three-dimensional coordinate measuring device according to one aspect of the present invention has an upper surface perpendicular to the Z axis, a lower surface opposite to the upper surface, and a first side surface along the Y axis direction. A platen on which the object to be measured is placed on the upper surface, a Y carriage that supports the measurement probe on the upper surface side of the platen and is movably arranged in the Y-axis direction, and a Y carriage in the Y-axis direction. In a three-dimensional coordinate measuring device provided with a support means for movably supporting a carriage, a groove formed along a first side surface of a platen and having a second side surface along the Y-axis direction. The groove is provided, and the supporting means is a first and second supporting member provided at two positions along the Y-axis direction of the Y carriage, and is provided on the upper surface between the first side surface and the second side surface. The first and second support members slidably arranged, and the third and fourth support members provided at two locations along the Y-axis direction of the Y carriage, which slide on the lower surface of the platen. It includes third and fourth support members that are movably arranged.

According to this aspect, the surface plate supports the Y carriage at two locations on the upper surface side where the first and second support members abut and two locations on the lower surface side where the third and fourth support members abut. Therefore, the runout of the Y carriage in the pitching direction (direction around the X axis) is appropriately suppressed.

In the three-dimensional coordinate measuring device according to another aspect of the present invention, the first support member and the third support member, and the second support member and the fourth support member are arranged at positions facing each other. It is preferable to use the aspect.

In the three-dimensional coordinate measuring device according to still another aspect of the present invention, the supporting means are the fifth and sixth supporting members provided at two locations along the Y-axis direction of the Y carriage, and the first one. The fifth and sixth support members slidably arranged on the side surface, and the seventh and eighth support members provided at two locations along the Y-axis direction of the Y carriage, the second side surface. It can be an embodiment including a seventh and eighth support members slidably arranged on the carriage.

According to this aspect, the runout of the Y carriage in the yawing direction (direction around the Z axis) is also appropriately suppressed.

In the three-dimensional coordinate measuring device according to still another aspect of the present invention, the Y carriage extends along the Z-axis direction and is arranged closer to the first side surface, and the first, second, and second carriages are arranged. A second strut member provided with the third and fourth support members and a second strut member extending along the Z-axis direction and arranged on a side far from the first side surface. A ninth support member slidable on the upper surface of the surface plate may be provided on the support member of the above.

In the three-dimensional coordinate measuring device according to still another aspect of the present invention, the Y-carriage is provided with a driving means for moving the Y-carriage in the Y-axis direction with respect to the surface plate, and the driving means is a first support member. The embodiment may include a roller that abuts on the first side surface at a position between the and the second support member, and a motor that rotates the roller.

In the three-dimensional coordinate measuring device according to still another aspect of the present invention, the support member may be an air pad.

In the three-dimensional coordinate measuring device according to still another aspect of the present invention, the surface plate may be a stone surface plate.

According to the present invention, the runout of the Y carriage in the pitching direction can be suppressed, and the measurement accuracy can be improved.

Perspective view showing the appearance of the three-dimensional coordinate measuring device to which the present invention is applied. Front view showing the appearance of the three-dimensional coordinate measuring device to which the present invention is applied. Front view showing the right side of the surface plate enlarged Right side view showing the right side of the surface plate enlarged Perspective view showing the Y carriage with the cover removed It is the top view which showed the upper surface of the surface plate, and is the figure which showed the arrangement with respect to the surface plate of the air pad provided in the Y carriage. It is the right side view which showed the right side surface of the surface plate, and is the figure which showed the arrangement with respect to the surface plate of the air pad provided in the Y carriage. Front view showing the groove part of the surface plate enlarged Perspective view showing the Z column removed from the X guide Perspective view showing the Z column removed from the X guide Perspective view showing the Z column removed from the X guide Perspective view showing the support part of the Z column removed from the X guide. Perspective view showing the support part of the Z column removed from the X guide. Schematic diagram showing the positional relationship of the support points where the Y guide of the surface plate supports the Y carriage from the upper surface side of the surface plate. Schematic diagram showing the positional relationship of the support points where the Y guide of the surface plate supports the Y carriage from the right side of the surface plate. Front view showing the appearance of the three-dimensional coordinate measuring device of Comparative Example 1 (schematic front view) Sectional view along line XVII-XVII in FIG. 16 (schematic sectional view) Front view showing the appearance of the three-dimensional coordinate measuring device of Comparative Example 2 (schematic front view) Front view showing the appearance of the three-dimensional coordinate measuring device of Comparative Example 3 (schematic front view) Front view (frontal schematic view) showing the appearance of the three-dimensional coordinate measuring device 1 of the present embodiment. Sectional view along line XXI-XXI in FIG. 20 (schematic sectional view) It is the top view which showed the upper surface of the surface plate, and is the figure which showed the arrangement of each air pad provided in a Y carriage, and a drive part. Front view showing the appearance of the three-dimensional coordinate measuring device of another embodiment (frontal schematic view)

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 and 2 are a perspective view and a front view showing the appearance of the three-dimensional coordinate measuring device 1 to which the present invention is applied.

The three-dimensional coordinate measuring device 1 shown in these figures has a surface plate 10 supported on an installation surface (floor surface) via a gantry 12. The surface plate 10 is integrally formed of a stone material such as granite or marble in a rectangular shape, and has a flat upper surface 10T on which an object to be measured is placed. The upper surface 10T is arranged parallel to the X-axis and the Y-axis, that is, perpendicular to the Z-axis.

A gate-shaped Y carriage 14 is installed on the upper surface 10T side of the surface plate 10. The Y carriage 14 is a right Y carriage, which is a first strut member extending along the Z-axis direction on each of the right side and the left side of the surface plate 10 when the surface plate 10 is viewed from the front side. It has a left Y carriage 18 which is a 16 and a second support column member, and a columnar X guide 20 which is bridged over the upper ends of the right Y carriage 16 and the left Y carriage 18 and extends along the X axis direction.

The lower end of the right Y carriage 16 is movably supported by a Y guide 42 described later along the Y-axis direction formed on the surface plate 10. Further, a drive unit that comes into contact with the Y guide 42 is provided at the lower end of the right Y carriage 16, and the right Y carriage 16 moves along the Y guide 42 by the driving force of the drive unit. The lower end of the left Y carriage 18 is slidably supported by the upper surface 10T of the surface plate 10.

As a result, the Y carriage 14 is supported so as to be movable in the Y-axis direction with respect to the surface plate 10, and the right Y carriage 16 is set as the drive side by the drive unit at the lower end of the right Y carriage 16, and the left Y carriage 14 is used. It moves in the Y-axis direction with 18 as the driven side.

The Z column 22 is movably supported by the X guide 20 along the X guide 20. The Z column 22 has a built-in drive unit that comes into contact with the X guide 20, and moves in the X-axis direction along the X guide 20 by the driving force of the drive unit.

Further, inside the Z column 22, a columnar Z carriage 24 extending along the Z axis is supported so as to be movable in the Z axis direction (see FIG. 2), and the lower end side of the Z carriage 24 is Z. It protrudes from the lower end side of the column 22. The Z column 22 has a built-in drive unit that comes into contact with the Z carriage 24, and the Z carriage 24 moves in the Z-axis direction by the driving force of the drive unit.

A measurement probe 26 such as a touch probe is attached to the lower end of the Z carriage 24. The measuring probe 26 has, for example, a rod-shaped stylus 28 having a tip sphere, and the measuring probe 26 includes the presence or absence of contact of the tip (tip sphere) of the stylus 28 with the measurement object and the measurement object at the tip of the stylus 28. The amount of displacement of the stylus 28 caused by contact with the stylus 28 is detected.

The three-dimensional coordinate measuring device 1 configured as described above measures by moving the Y carriage 14 in the Y axis direction, moving the Z column 22 in the X axis direction, and moving the Z carriage 24 in the Z axis direction. The stylus 28 of the probe 26 is moved in the X, Y, and Z axis directions, and the tip (tip sphere) of the stylus 28 is moved along the surface of the object to be measured placed on the upper surface 10T of the surface plate 10. Then, the position of the Y carriage 14 in the Y-axis direction (movement amount), the position of the Z column 22 in the X-axis direction (movement amount), the position of the Z carriage 24 in the Z-axis direction (movement amount), and the stylus 28 at that time. By measuring the position (displacement amount) of, the three-dimensional coordinates of each position on the surface of the object to be measured are measured. Since the processing related to the measurement of the three-dimensional coordinates is well known, detailed description thereof will be omitted.

Next, a Y drive mechanism that movably supports the Y carriage 14 in the Y-axis direction and moves the Y-carriage 14 in the Y-axis direction will be described.

First, the support means (Y guide mechanism) for the Y carriage 14 in the Y drive mechanism will be described.

3 and 4 are an enlarged front view and a right side view of the right side portion of the surface plate 10.

As shown in FIG. 3, the surface plate 10 has an upper surface 10T and a lower surface 10B perpendicular to the Z axis, and a right side surface 10R perpendicular to the X axis. Further, a groove 40 is formed along the Y-axis direction on the upper surface 10T side of the surface plate 10 near the right side surface 10R of the surface plate 10.

In FIGS. 1 and 2, a stretchable covering member such as a bellows cover is installed in the upper opening of the groove 40, and a plate-shaped covering member such as a metal cover is attached to the front and rear side surfaces of the surface plate 10. Although the state is shown, FIGS. 3 and 4 show a state in which the covering members are removed.

The groove 40 has a right side surface 40R and a left side surface 40L perpendicular to the X axis and a bottom surface 40B perpendicular to the Z axis.

As a result, the right side surface 40R of the groove 40, the right side surface 10R of the surface plate 10, the upper surface 10T of the surface plate 10 between them, and the lower surface 10B of the surface plate 10 extend along the Y-axis direction. The Y guide 42 is formed.

The right side surface 10R of the surface plate 10 and the right side surface 40R and the left side surface 40L of the groove 40 do not necessarily have to be surfaces perpendicular to the X axis as long as they are formed along the Y-axis direction. The lower surface 10B of the board 10 and the bottom surface 40B of the groove 40 do not necessarily have to be planes perpendicular to the Z axis.

Further, in the following, the right side surface 40R of the groove 40 is the left side surface 42L of the Y guide 42, the right side surface 10R of the surface plate 10 is the right side surface 42R of the Y guide 42, and the upper surface 10T of the surface plate 10 between them is the Y guide 42. The upper surface 42T and the lower surface 10B of the surface plate 10 are referred to as the lower surface 42B of the Y guide 42.

On the other hand, FIG. 5 shows a perspective view of the Y carriage 14 with the covers of each part removed, and as shown in FIGS. 4 and 5, the lower end portion of the right Y carriage 16 is in the Y-axis direction. Is provided with a wide support portion 50.

Further, the support portion 50 is formed in a bifurcated shape when viewed from the front side as shown in FIG.

Note that FIGS. 3 and 4 show a state in which the covering member covering the support portion 50 is removed.

As shown mainly in FIG. 3, the support portion 50 has a base end portion 52 facing the upper surface 42T of the Y guide 42 and arranged along a direction (horizontal direction) orthogonal to the Z axis, and a base end portion 52. The right side portion 54 extending in the Z-axis direction and arranged on the side facing the right side surface 42R of the Y guide 42, and the base end portion 52 extending in the Z-axis direction to the left side surface 42L of the Y guide 42. It has a left side portion 56 arranged on the opposite side.

Further, at the lower end of the right side portion 54, support plates 58A and 58A extending in the X-axis direction to a position facing the lower surface 42B of the Y guide 42 are provided as the tip end portion 58 of the support portion 50.

As shown below, each of the base end portion 52, the right side portion 54, the left side portion 56, and the tip portion 58 of the support portion 50 can be slidable with respect to the Y guide 42 by ejecting air. A plurality of disc-shaped air pads are provided. Further, a disk-shaped air pad that can slide with respect to the upper surface 10T of the surface plate 10 by ejecting air to the lower end of the left Y carriage 18 is also provided.

6 and 7 are a top view and a right side view showing the upper surface 10T and the right side surface 10R of the surface plate 10, and show the arrangement of the air pad provided on the Y carriage 14 with respect to the surface plate 10.

In these figures, the two air pads 62F and 62E arranged along the upper surface 42T of the Y guide 42 are located at two locations (on a straight line parallel to the Y axis) along the Y axis direction at the base end portion 52 of the support portion 50. It is provided at two positions), and is arranged downward facing the upper surface 42T of the Y guide 42.

The two air pads 64F and 64E arranged along the right side surface 42R of the Y guide 42 are provided at two locations along the Y-axis direction (two locations on a straight line parallel to the Y-axis) on the right-side portion 54 of the support portion 50. It is provided at a position and is arranged to the left facing the right side surface 42R of the Y guide 42.

The two air pads 66F and 66E arranged along the left side surface 42L of the Y guide 42 (the right side surface 40R of the groove 40) are provided at two locations (parallel to the Y axis) along the Y axis direction on the left side portion 56 of the support portion 50. It is provided at two positions on a straight line) and is arranged to the right facing the left side surface 42L of the Y guide 42.

The two air pads 68F and 68E (see FIGS. 3 and 7) arranged along the lower surface 42B of the Y guide 42 are provided at two locations (parallel to the Y axis) along the Y axis direction at the tip portion 58 of the support portion 50. It is provided at two positions on a straight line) and is arranged upward facing the lower surface of the Y guide 42.

The air pad 70 arranged on the upper surface near the left side surface of the surface plate 10 is provided at the lower end portion of the left Y carriage 18, and is arranged downward facing the upper surface 10T of the surface plate 10.

Here, the air pads 62F, 64F, 66F, 68F installed on the front side (front side) of each of the base end portion 52, the right side portion 54, the left side portion 56, and the tip portion 58 of the support portion 50 are in the Y-axis direction. The air pads 62E, 64E, 66E, 68E arranged at substantially the same position (that is, arranged along the same XZ plane) and rearward (rear side) are substantially the same position with respect to the Y-axis direction. Is placed in.

The air pads 64F and 64E installed on the right side portion 54 of the support portion 50 and the air pads 66F and 66E installed on the left side portion 56 are arranged at positions facing each other (that is, substantially the same position in the Z-axis direction).

The air pads 62F and 62E installed at the base end portion 52 of the support portion 50 and the air pads 68F and 68E installed at the tip end portion 58 are arranged at positions facing each other (that is, substantially the same position in the X-axis direction). ..

The air pad 70 installed at the lower end of the left Y carriage 18 has the Y axis of the center of gravity of all the members (Y carriage 14 and Z column 22) whose position with respect to the Y axis direction moves in the Y axis direction together with the Y carriage 14. It is placed at a position that roughly matches the position in the direction.

Further, while the air pads 62F, 62E, 70 have a diameter of 110 mm, for example, the air pads 64F, 64E, 66F, 66E have a diameter smaller than that of the air pads 62F, 62E, 70, for example, 80 mm in diameter. .. Further, as the air pads 68F and 68E, those having a diameter smaller than that of the air pads 64F, 64E, 66F and 66E, for example, having a diameter of 60 mm are used.

As a reference, the surface plate 10 has a width (width) of about 800 mm to about 1000 mm in the X-axis direction and a width (depth) of about 1200 mm to about 2700 mm in the Y-axis direction. The width (height) in the Z-axis direction is about 600 mm to about 800 mm, and the support portion 50 has a width (depth) of about 650 mm in the Y-axis direction.

According to the support means of the Y carriage 14 configured as described above, the Y carriage 14 is Y via the air pads 62F, 62E, 64F, 64E, 66F, 66E, 68F, 68E of the support portion 50 in the right Y carriage 16. It is supported by the guide 42 (surface plate 10). That is, the Y carriage 14 is supported by the Y guide 42 by the engagement between the support portion 50 and the Y guide 42. Along with this, the Y carriage 14 is supported by the surface plate 10 (upper surface 10T) via the air pad 70 on the left Y carriage 18.

Further, by ejecting air from the air pads 62F, 62E, 64F, 64E, 66F, 66E, 68F, 68E, 70, the air pads 62F, 62E, 64F, 64E, 66F of the support portion 50 in the right Y carriage 16 The 66E, 68F, and 68E are slidable with respect to the Y guide 42 in the Y-axis direction, and the air pad 70 on the left Y carriage 18 is slidable with respect to the upper surface 10T of the surface plate 10.

Therefore, the Y carriage 14 is in a state where it can move in the Y-axis direction with respect to the surface plate 10.

Subsequently, the driving means of the Y carriage 14 in the Y driving mechanism will be described.

As shown in FIG. 4, a drive unit 80 is provided on the right side portion 54 of the support unit 50. As shown in FIGS. 6 and 7, the drive unit 80 is arranged at a position substantially intermediate between the two air pads 64F and 64E provided on the right side portion 54 of the support unit 50.

The drive unit 80 is integrally formed by assembling a motor 82, a rotatable roller 84, and a reduction mechanism for connecting them so as to be able to transmit power to a support member. When the motor 82 is driven, the roller 84 is integrally configured. Rotate.

As shown in FIG. 6, the drive unit 80 has a Y guide 42 at a position where the rotation axis of the roller 84 is parallel to the Z axis and the outer peripheral surface of the roller 84 is substantially intermediate between the two air pads 64F and 64E. It is installed on the right side portion 54 of the support portion 50 so as to abut on the right side surface 42R (right side surface 10R of the surface plate 10).

Therefore, by driving the motor 82 of the drive unit 80 to rotate the roller 84, the support unit 50 moves along the Y guide 42, and the Y carriage 14 moves in the Y-axis direction.

As the driving means of the Y carriage 14, in addition to the driving unit 80, a driving unit that contacts the left side surface 42L of the Y guide 42 may be provided, for example, facing the driving unit 80, or Y instead of the driving unit 80. Only the drive unit that comes into contact with the left side surface 42L of the guide 42 may be provided.

Subsequently, the position detecting means of the Y carriage 14 in the Y drive mechanism will be described.

FIG. 8 is an enlarged front view showing a portion of the groove 40 of the surface plate 10. As shown in the figure, on the left side surface 40L of the groove 40, for example, a long plate-shaped scale 112 constituting an optical linear encoder 110 and provided with a grid scale is installed along the Y-axis direction. Will be done.

On the other hand, on the left side portion 56 of the support portion 50, an optical sensor 114 constituting the linear encoder 110 is installed with a support member, and is arranged at a position facing the scale 112. Then, the detection signal caused by the grid scale of the scale 112 formed at the position facing the optical sensor 114 is output from the optical sensor 114.

According to the linear encoder 110, when the Y carriage 14 moves in the Y-axis direction, the optical sensor 114 moves in the Y-axis direction together with the Y carriage 14, and the position of the optical sensor 114 facing the scale 112 changes. At this time, the position of the Y carriage 14 in the Y-axis direction is detected based on the detection signal output from the optical sensor 114.

Next, an X drive mechanism that movably supports the Z column 22 in the X-axis direction and moves the Z column 22 in the X-axis direction will be described.

First, the supporting means (X guide mechanism) of the Z column 22 in the X drive mechanism will be described.

FIG. 5 shows the Y carriage 14 with the cover removed as described above, and FIGS. 9, 10, and 11 show the Z column 22 removed from the X guide 20. As shown in these figures, the Z column 22 includes a support portion 200 to which various parts are assembled and corresponds to an X carriage, and the support portion 200 is provided with a square columnar X guide 20. A rectangular X-guide insertion hole 202 is provided along the X-axis direction to be inserted.

In the support portion 200, the X guide is blown to each of the front surface 202F, the rear surface 202E, the upper surface 202T, and the lower surface 202B (referred to as the front surface 202F of the X guide insertion hole 202) that define the X guide insertion hole 202. A disk-shaped air pad that is slidable with respect to 20 is provided.

As shown in FIG. 10, a total of four air pads 210, 210, 210, 210 are arranged on the front surface 202F of the X guide insertion hole 202, one at each of four symmetrical locations vertically and horizontally, and the X guide is provided. It is arranged backward so as to face the front surface 20F (see FIG. 5) of the 20.

As shown in FIG. 11, a total of three air pads 212, 212, and 212 are arranged on the rear surface 202E of the X guide insertion hole 202, one at each of the upper two locations and the lower one, and the X guide 20 is provided. It is arranged forward facing the rear surface 20E (see FIG. 5).

As shown in FIG. 9, a total of two air pads 214 and 214 are arranged on the upper surface 202T of the X guide insertion hole 202, one at each of the two left and right locations, and the upper surface 20T of the X guide 20 (see FIG. 5). It is placed facing downwards.

As shown in FIG. 10, one air pad 216 is arranged on the lower surface 202B of the X guide insertion hole 202, and is arranged upward facing the lower surface 20B (see FIG. 5) of the X guide 20.

According to the support means of the Z column 22 configured as described above, when the X guide 20 is inserted into the X guide insertion hole 202 of the support portion 200, the support portion 200 passes through the air pads 210, 212, 214, 216. Supported by the X guide 20, the Z column 22 is supported by the X guide 20 via the support portion 200.

Further, by ejecting air from the air pads 210, 212, 214, 216, the air pads 210, 212, 214, 216 of the support portion 200 are in a state of being slidable in the X-axis direction with respect to the X guide 20. ..

Therefore, the Z column 22 is in a state of being movable in the X-axis direction.

Subsequently, the driving means of the Z column 22 in the X driving mechanism will be described.

As shown in FIGS. 9 to 11, the rear surface 202E of the X guide insertion hole 202 has the same configuration as the drive unit 80 in the Y drive mechanism described above, and includes a motor 222 and a roller 224 (see FIG. 11). A drive unit 220 is provided. The drive unit 220 is installed on the rear surface 202E of the X guide insertion hole 202 so that the rotation axis of the roller 224 is parallel to the Z axis, and the outer peripheral surface of the roller 224 is on the upper side of the rear surface 202E of the X guide insertion hole 202. It is installed so as to abut on the rear surface 20E (see FIG. 5) of the X guide 20 at a position substantially intermediate between the two installed air pads 212 and 212.

Therefore, by driving the motor 222 of the drive unit 220 to rotate the roller 224, the support unit 200 moves along the X guide 20, and the Z column 22 moves in the X-axis direction.

The X guide 20 and the support portion 200 are provided with an optical linear encoder similar to the above-mentioned linear encoder 110 in the Y drive mechanism as a position detecting means of the Z column 22 in the X drive mechanism. In, a long plate-shaped scale is installed along the X-axis direction, and an optical sensor is arranged at a position facing the scale on the support portion 200.

Next, a Z drive mechanism that movably supports the Z carriage 24 in the Z-axis direction and moves the Z-carriage 24 in the Z-axis direction will be described.

First, the supporting means (Z guide mechanism) of the Z carriage 24 in the Z drive mechanism will be described.

12 and 13 show a state in which the Z carriage 24 is removed from the support portion 200 of the Z column 22 shown in FIGS. 9 to 11, and as shown in these views, the support portion 200 Is provided with a rectangular Z-carriage insertion hole 250 along the Z-axis direction through which the square columnar Z-carriage 24 is inserted on the front side of the X-guide insertion hole 202.

In the support portion 200, air is provided in each of the front surface 250F, the rear surface 250E, the right side surface 250R, and the left side surface 250L (referred to as the front surface 250F of the Z carriage insertion hole 250) defining the Z carriage insertion hole 250 (see FIG. 13). An air pad that can slide with respect to the Z carriage 24 is provided by ejecting.

Near the lower opening of the Z carriage insertion hole 250, as shown in FIG. 12, a total of four air pads, one for each of the front 250F, the rear 250E, the right side 250R, and the left side 250L of the Z carriage insertion hole 250. 260, 262, 264, 266 are arranged, and each of the air pads 260, 262, 264, 266 is the front surface 24F, the rear surface 24E, the right side surface 24R, and the left side surface 24L (see FIG. 11) of the Z carriage 24, respectively. It is arranged facing backward, forward, left, and right facing the carriage.

Near the upper opening of the Z carriage insertion hole 250, as shown in FIG. 13, a total of three air pads 260, 262, 264, one for each of the front 250F, the rear 250E, and the right side 10R of the Z carriage insertion hole 250. Are arranged, and each of the air pads 260, 262, and 264 is arranged backward, forward, and left facing each of the front surface 24F, the rear surface 24E, and the right side surface 24R of the Z carriage 24.

On the other hand, two air pads 266 and 266 are arranged on the left side surface 250L of the Z carriage insertion hole 250 near the upper opening of the Z carriage insertion hole 250, and these air pads 266 and 266 face the left side surface 24L of the Z carriage 24. And it is placed facing right.

According to the support means of the Z carriage 24 configured as described above, when the Z carriage 24 is inserted into the Z carriage insertion hole 250 of the support portion 200, the support portion 200 passes through the air pads 260, 262, 264, and 266. Supports the Z carriage 24.

Further, by ejecting air from each of the air pads 260, 262, 264, and 266, each of the air pads 260, 262, 264, and 266 of the support portion 200 becomes slidable with respect to the Z carriage 24, and the Z carriage 24 becomes slidable. It is in a state where it can be moved in the Z-axis direction.

Subsequently, the driving means of the Z carriage 24 in the Z driving mechanism will be described.

As shown in FIGS. 12 and 13, the front surface 250F of the Z carriage insertion hole 250 has the same configuration as the drive unit 80 in the Y drive mechanism described above, and includes a motor 272 and a roller 274 (see FIG. 13). A drive unit 270 is provided. The drive unit 270 is installed on the front surface 250F of the Z carriage insertion hole 250 so that the rotation axis of the roller 274 is parallel to the X axis, and the outer peripheral surface of the roller 274 is installed on the front surface 250F of the Z carriage insertion hole 250. It is installed so as to abut on the front surface 24F of the Z carriage 24 at a position substantially intermediate between the two air pads 260 and 260.

Therefore, by driving the motor 272 of the drive unit 270 to rotate the roller 274, the Z carriage 24 moves in the Z-axis direction with respect to the support unit 200.

The Z carriage 24 and the support portion 200 are provided with an optical linear encoder similar to the above-mentioned linear encoder 110 in the Y drive mechanism as a position detecting means of the Z carriage 24 in the Z drive mechanism. In, a long plate-shaped scale is installed along the Z-axis direction, and an optical sensor is arranged on the support portion 200 at a position facing the scale.

Further, the cable protection tube 278 shown in FIGS. 9 to 13 is a bendable guide member that guides the cable by inserting it inside. The cable of the measurement probe 26 attached to the lower end of the Z carriage 24 is inserted and arranged inside the Z carriage 24 and inside the cable protection tube 278 inside the Z column 22, and interference with other members is prevented. ..

In the three-dimensional coordinate measuring device 1 configured as described above, the effect of suppressing the runout of the Y carriage 14 in the Z-axis direction (yawing direction) and the X-axis direction (pitching direction) will be mainly described.

FIG. 14 is a schematic view showing the positional relationship of the support points where the Y guide 42 of the surface plate 10 supports the Y carriage 14 from the upper surface 10T side of the surface plate 10.

In the figure, the two front and rear support points P1 and P2 existing on the left side surface 42L of the Y guide 42 formed on the surface plate 10 indicate the positions where the air pads 66F and 66E of the Y carriage 14 (support portion 50) come into contact with each other. The two front and rear support points P3 and P4 existing on the right side surface 42R of the Y guide 42 indicate the positions where the air pads 64F and 64E of the Y carriage 14 (support portion 50) abut, and are present on the right side surface 42R of the Y guide 42. The support point P0 is a position where the roller 84 of the drive unit 80 of the Y carriage 14 (support unit 50) comes into contact with the roller 84 (see FIG. 6).

Further, the support points P1 and P2 indicate fixed support points, and the support points P3 and P4 indicate auxiliary support points. That is, the air pads 66F and 66E, which are the fixed support points P1 and P2, cannot move forward and backward in the normal direction of the left side surface 42L of the Y guide 42, which is the guide surface on which they slide, on the support portion 50 of the Y carriage 14. Supported by. On the other hand, the air pads 64F and 64E serving as auxiliary support points P3 and P4 are located in the support portion 50 of the Y carriage 14 with respect to the normal direction of the right side surface 42R of the Y guide 42, which is the guide surface on which they slide. It is supported so that it can move forward and backward, and is urged in the direction of contacting the right side surface 42R.

According to this, when the roller 84 of the drive unit 80 is pressed against the right side surface 42R of the Y guide 42, the Y guide 42 supports one of the right side surfaces 42R with the support points P3 and P4 as auxiliary support points. It is stable in a state of being supported by the two support points P1 and P2 of the point P0 and the left side surface 42L.

Therefore, the angular position of the Y carriage 14 in the Z-axis direction (yaw direction) is uniquely determined by the positions of the support points P1 and P2, and the deflection in the yaw direction is suppressed. Then, by suppressing the deflection of the X guide 20 (X axis) in the yawing direction, the measurement object is measured in the measurement area (the area that does not interfere with the Y carriage 14) on the upper surface 10T of the surface plate 10. The X coordinate value and the Y coordinate value can be obtained with high accuracy with reference to the position of the Y guide 42 (left side surface 42L).

FIG. 15 is a schematic view showing the positional relationship of the support points where the Y guide 42 of the surface plate 10 supports the Y carriage 14 from the right side surface 10R side of the surface plate 10.

In the figure, the two front and rear support points P5 and P6 existing on the upper surface 42T of the Y guide 42 formed on the surface plate 10 indicate the positions where the air pads 62F and 62E of the Y carriage 14 (support portion 50) come into contact with each other. The two front and rear support points P7 and P8 existing on the lower surface 42B of the Y guide 42 indicate the positions where the air pads 68F and 68E of the Y carriage 14 (support portion 50) come into contact with each other (see FIG. 7).

According to this, the Y guide 42 supports the Y carriage 14 not only by the two front and rear support points P5 and P6 on the upper surface 42T but also by the two front and rear support points P7 and P8 on the lower surface 42B.

Therefore, the runout of the Y carriage 14 in the X-axis direction (pitching direction) is suppressed not only by the support points P5 and P6 but also by the support points P7 and P8, and when the Y carriage 14 is moved in the Y-axis direction at high speed. Even so, the runout of the Y carriage 14 in the pitching direction is suppressed.

In particular, since the drive unit 80 is arranged between the support points P5 and P6 and the support points P7 and P8 in the Z-axis direction (see FIG. 7 and the like), the driving force of the drive unit 80 causes the Y carriage 14 to be pitched in the pitching direction. Since the rotational force is less likely to be generated, the Y carriage 14 is prevented from swinging in the pitching direction.

The position of the drive unit 80 in the Y-axis direction is a position that substantially coincides with the position of the center of gravity of all the members (Y-carriage 14 and Z column 22) that move in the Y-axis direction together with the Y-carriage 14. Is desirable.

Then, by suppressing the runout of the Z carriage 24 (Z axis) in the pitching direction, the Y coordinate value and the Z coordinate value of the measurement target in the measurement region measured by the measurement probe 26 are set to the Y guide 42 (upper surface 42T). ) Is used as a reference to obtain high accuracy.

Further, by forming the groove 40 in the surface plate 10, a part of the area along the right side surface 10R of the surface plate 10 is made into the Y guide 42, so that the Y guide 42 is made of a separate member as compared with the case where the Y guide 42 is made of a separate member. Thermal deformation of the Y guide 42 is less likely to occur, and the straightness of the Y guide 42 can be easily maintained. Further, even when the left and right side surfaces of the surface plate 10 are used as Y guides, since the respective surfaces of the Y guide 42 are close to each other, the relative change amount of each surface is small and the straightness of the Y guide 42 is small. Is sustained.

Therefore, the deflection of the Y carriage 14 in the yawing direction and the pitching direction due to the change in the position of the Y carriage 14 in the Y axis direction is small, and the movement of the Y carriage 14 in the Y axis direction can be continuously stabilized and sustained. The measurement accuracy can be maintained. Further, the Y guide 42 (Y guide mechanism) can be made simpler and cheaper than the case where the Y guide 42 is made of a separate member.

Therefore, by making a part of the surface plate 10 a Y guide 42, the shape change of the Y guide 42 during measurement is small as compared with the case where the Y guide 42 is composed of a separate member from the surface plate 10, and the Y guide It becomes easy to reduce the measurement error due to the curvature of 42 or the like by the correction in the calculation. However, the surface plate 10 does not necessarily have to be a stone surface plate.

As described above, the three-dimensional coordinate measuring device 1 of the above-described embodiment may have a configuration in which the left and right sides are inverted, and the groove 40 and the Y guide 42 are not positioned along the right side surface 10R of the surface plate 10, but are on the surface plate. It may be formed at a position along the left side surface of 10.

Further, in the above embodiment, the case where an air pad (air bearing) is used as a support member that slidably contacts each surface of the Y guide 42 or the like is shown, but a support member of a type other than the air pad may also be used. Good.

The effects of the above three-dimensional coordinate measuring device 1 will be supplementarily described below.

In the three-dimensional coordinate measuring device 1 of the above embodiment, the axis of the roller 84 of the drive unit 80 is arranged in the direction perpendicular to the upper surface 10T of the surface plate 10. Therefore, since the rollers 84 come into contact with each other on the vertical surface of the surface plate 10, dust is not bitten, and accurate measurement can be performed with reference to the side surface of the surface plate 10.

Further, the roller 84 is driven along the side surface (right side surface 10R) of the surface plate 10. Therefore, even if the surface plate 10 is slightly deformed, the measurement can be performed with the surface plate 10 as a reference. If the roller 84 moves along another rail different from the surface plate 10, it will not be synchronized with the deformation of the surface plate 10 due to other factors such as thermal expansion of the other rail.

Further, the air pads 64F, 64E, 66F, and 66E are also arranged in the vertical direction along the side surface of the surface plate 10. Therefore, the position is set with reference to the surface plate 10 in the same manner as described above. In addition, it is possible to reduce the yawing error that swings left and right with respect to the traveling direction when the Y carriage 14 is moved.

Further, the rollers 84 of the drive unit 80 arranged in the vertical direction are arranged so as to be sandwiched between the air pads 66F and 66E similarly arranged in the vertical direction. Therefore, even in a sudden drive, yawing error and vibration can be reduced without losing the posture by sandwiching the front and rear with air pads.

Further, the distance (distance) between the support points P1 and the support point P2 in the Y carriage 14 is sufficiently large with respect to the distance (interval) between the support points P1 and P2 and the drive point P0. Therefore, the vibration of the Y carriage 14 can be reduced, and the yawing error in which the moving direction swings to the left or right with respect to the moving direction can be reduced.

Further, the air pads 66F and 66E are arranged so as to be perpendicular to the side surface of the groove 40 of the surface plate 10. Therefore, by forming the groove 40 in the surface plate 10 and using the support points P1 and P2 by the air pads 66F and 66E as the side surfaces of the groove 40 of the surface plate 10, it follows the deformation such as thermal expansion of the surface plate 10. It can be measured with reference to the surface plate 10.

Further, the air pads 66F and 66E facing the support points P3 and P4 by the air pads 64F and 64E exist as support points P1 and P2 on the side surface of the groove 40 of the surface plate 10, and are supported by the Y guide 42. Therefore, the side surface of the surface plate 10 is used as a reference, and the Y carriage 14 is supported only on the drive side (the right Y carriage 16 side on which the drive unit 80 is arranged) with respect to the driven side (left Y carriage 18 side). .. Therefore, the sliding resistance on the driven side becomes negligible, and the yawing error is significantly reduced.

Further, only the air pad 70 in the Z-axis direction is arranged on the driven side of the Y carriage 14, and there is no air pad that suppresses the Y-axis direction. Therefore, the movement in the Y-axis direction follows the drive side without creating an extra resistance on the driven side. As a result, vibration can be reduced and yawing can be reduced.

Further, the positions of the air pads 70 in the Z-axis direction on the driven side of the X guide 20 and the Y carriage 18 in the Y-axis direction are the air pads 66F, 66E (support points P1, P2) or the air pads 64F, 64E on the drive side of the Y carriage 18. It exists between (support points P3 and P4). Therefore, even in a sudden acceleration / deceleration, only the moments of the X guide 20 and the measuring unit are received within the width of the support points P1 and P2 (or the support points P3 and P4), and there is almost no sliding resistance. As a result, vibration and yawing errors are extremely small.

Next, the operation and effect of the three-dimensional coordinate measuring device 1 of the present embodiment will be described in more detail by comparing the three-dimensional coordinate measuring device 1 of the present embodiment with the three-dimensional coordinate measuring devices of Comparative Examples 1 to 3. The present invention is not limited to the following description of the effects.

FIG. 16 is a front view (frontal schematic view) showing the appearance of the three-dimensional coordinate measuring device 300 of Comparative Example 1 disclosed in JP-A-5-31556. Further, FIG. 17 is a cross-sectional view (schematic cross-sectional view) along the line XVII-XVII in FIG. In the three-dimensional coordinate measuring device 300 of Comparative Example 1, those having the same function or configuration as the three-dimensional coordinate measuring device 1 of the present embodiment are designated by the same reference numerals and the description thereof will be omitted.

As shown in FIGS. 16 and 17, in the three-dimensional coordinate measuring device 300 of Comparative Example 1, the support portion 50 that supports the right Y carriage 16 on the side directly driven by the drive unit 301 (hereinafter, abbreviated as the drive side). Is supported by the surface plate 10 via the air pad 302R and the air pad 302T. The air pad 302R is arranged on the right side surface of the surface plate 10, and the air pad 302T is arranged on the right end side of the upper surface 10T of the surface plate 10. Further, the air pads 302T are provided at two positions along the Y direction (see FIG. 17).

On the other hand, in the three-dimensional coordinate measuring device 300 of Comparative Example 1, the left Y carriage 18 on the driven side (hereinafter abbreviated as the driven side) that follows the right Y carriage 16 on the driving side and moves in the Y direction is the air pad 303T. It is slidably supported on the upper surface 10T of the surface plate 10 via the air pad 303L. The air pad 303T is arranged on the upper surface 10T of the surface plate 10. Further, the lower end of the left Y carriage 18 has a support portion 18a facing the left side surface of the surface plate 10, and the support portion 18 arranges the air pad 303T on the left side surface of the surface plate 10.

The drive unit 301 has basically the same configuration as the drive unit 80 of the present embodiment, and is provided in the vicinity of the air pad 302R. The rectangular frame represented by the alternate long and short dash line in FIG. 17 indicates the position of the drive unit 301.

In the three-dimensional coordinate measuring device 300 of Comparative Example 1, two air pads 302T are arranged along the Y direction on the right end side of the upper surface 10T of the surface plate 10, but the three-dimensional coordinate measuring device 1 of the present embodiment is different from the three-dimensional coordinate measuring device 1 of the present embodiment. Unlike this, the air pad is not arranged on the lower surface side of the surface plate 10. That is, since the three-dimensional coordinate measuring device 300 of Comparative Example 1 is not provided with the surface plate 10 or the air pad facing the lower surface of the Y guide (not shown) provided on the surface plate 10, the drive side The portion that determines the position of the right Y carriage 16 in the vertical direction (Z-axis direction) is only the upper surface of the surface plate 10. Therefore, in the three-dimensional coordinate measuring device 300 of Comparative Example 1, a pitching error becomes a problem.

In order to reduce the pitching error, the positional relationship between the drive unit 301 that drives the right Y carriage 16 in the Y direction and the air pad that supports the right Y carriage 16 is important. For example, in the three-dimensional coordinate measuring device 300 of Comparative Example 1, since the drive unit 301 is provided below the upper surface 10T of the surface plate 10, the right Y carriage 16 momentarily moves with the upper surface 10T of the surface plate 10 as a fulcrum. It will tilt (swing) around the X-axis. Therefore, when the right Y carriage 16 on the drive side is supported only on the surface plate 10 as in the three-dimensional coordinate measuring device 300 of Comparative Example 1, the support point is only one point in the vertical direction. When driven by the drive unit 301, a rotational moment acts with the support point on the surface plate 10 as a fulcrum. As a result, the right Y carriage 16 swings around the X axis, and the pitching error becomes remarkable.

Therefore, in order to reduce the pitching error, the upper and lower surfaces of the surface plate 10 are sandwiched between the air pads 62E, 62F, 68E, 68F (see FIG. 7) as in the three-dimensional coordinate measuring device 1 of the present embodiment. It is necessary to provide a drive unit 80 (see FIG. 7) between the lower surfaces. As a result, when the Y carriage 14 (right Y carriage 16) is moved in the Y direction, both the upper and lower surfaces of the surface plate 10 become the support points of the right Y carriage 16, and the positions sandwiched between these two support points. Since the drive unit 80 is located at the center, a pitching error is less likely to occur even when the Y carriage 14 is accelerated and decelerated. In order to suppress the pitching error during acceleration and deceleration, the drive unit 80 is located at the center of gravity of the Y carriage 14 (right Y carriage 16) in the Y direction, for example, at the center position of the air pad 62E and the air pad 62F. Is preferable.

Further, in the three-dimensional coordinate measuring device 300 of Comparative Example 1, the air pads 302R and the air pads 303L are arranged on both side surfaces (vertical surfaces on both sides) of the surface plate 10 in FIG. In this case, it seems to be stable in moving the Y carriage 14 back and forth in the Y direction, but the yawing error becomes large when the Y carriage 14 is moved back and forth in the Y direction.

That is, when the air pads 302R and the air pads 303L are arranged on both side surfaces of the surface plate 10, the right Y carriage 16 on the drive side and the left Y carriage 18 on the driven side are on the side that controls the main drive operation and the operation thereof. The distinction from the following side is not clear, and both have similar sliding resistance. As a result, when the Y carriage 14 is moved in the Y direction, the positional relationship between the right Y carriage 16 and the left Y carriage 18 in the Y direction is not constant, and the yawing occurs, for example, by swinging around the Z axis. The error becomes large. Therefore, as in the present embodiment, the right Y carriage 16 on the drive side should be moved along the Y guide 42 (see FIG. 3), and the left Y carriage 18 on the driven side should have the sliding resistance as small as possible. Since the left Y carriage 18 moves following the right Y carriage 16 on the drive side, the above-mentioned swing around the Z axis does not occur.

Further, in the three-dimensional coordinate measuring device 300 of Comparative Example 1, the drive unit 301 is not arranged in the vicinity of the air pad 303L on the driven side, and the air pad 303L on the driven side is relative to the air pad 302R on the drive side. It is located on the opposite side of the Y carriage 14, and presses both side surfaces of the surface plate 10 together with the air pad 302R. In this case, since the air pad 303L on the driven side is located on the opposite side of the surface plate 10 and away from the drive unit 301, the drive unit 301 is used as a fulcrum by sliding the air pad 303L and the left side surface of the surface plate 10. A large rotational moment is generated.

Further, the air pad 302R and the air pad 303L are moved in the direction perpendicular to the pressing direction of the surface plate 10 (Y direction) while being pushed from both sides so as to sandwich both side surfaces of the surface plate 10 by the air pad 302R and the air pad 303L. In this case, the yawing error is remarkably deteriorated as the balance of the sliding resistance during this moving operation is slightly lost.

As a method for reducing such yawing error, for example, Japanese Patent Application Laid-Open No. 7-218247 describes that the Y carriage 14 is prevented from twisting and bending even when the Y carriage 14 is moved in the Y direction at a large acceleration. It is disclosed to provide a drive unit having a special structure possible. However, when the drive unit having this special structure is adopted, there is a problem that the three-dimensional coordinate measuring device 300 becomes large and the structure of the drive unit becomes complicated. Therefore, the three-dimensional coordinate measuring device 300 of Comparative Example 1 has a problem that a yawing error occurs when the Y carriage 14 is moved.

Further, when the Y carriage 14 (right Y carriage 16) is supported only on the surface plate 10, the pitching error when driving the Y carriage 14 also affects the yawing error. That is, when a pitching error occurs, one of the front and rear air pads 302T in the Y direction is separated from the upper surface 10T of the surface plate 10, and the other is closer to the upper surface 10T. At that time, the right Y carriage 16 and the left Y carriage 18 should have an asymmetric structure and the sliding resistance of the right Y carriage 16 on the driving side should be larger than that of the left Y carriage 18 on the driven side. Therefore, the sliding resistance cannot be balanced on the left and right due to the change due to the pitching error. Therefore, the Y carriage 14 is further deformed so as to be greatly twisted. As a result, the yawing error may worsen.

Further, when the air pad 302T is arranged on the upper surface side of the surface plate 10 as in the three-dimensional coordinate measuring device 300 of Comparative Example 1, but the air pad is not arranged on the lower surface side, the load of the Y carriage 14 is on the right side of the drive side. It is divided into both the Y carriage 16 and the left Y carriage 18 on the driven side substantially evenly. If half the weight of the Y carriage 14 is applied to the driven side, the sliding resistance of the left Y carriage 18 on the driven side increases accordingly. As a result, the yawing error becomes large.

In the three-dimensional coordinate measuring device 300 of Comparative Example 1, no air pad is provided on the lower surface of the surface plate 10, and the right Y carriage 16 has only one support point in the vertical direction. In addition to the pitching error, swinging of the right Y carriage 16 around the Y axis, that is, a rolling error may occur. Even when such a rolling error occurs, the sliding resistance cannot be balanced on the left and right as in the case where the pitching error occurs, which may lead to deterioration of the yawing error.

On the other hand, in the right Y carriage 16 of the three-dimensional coordinate measuring device 1 of the present embodiment, the air pads 62E, 62F, 68E, 68F (see FIG. 7) are pressed not only from the upper surface side but also from the lower surface side of the surface plate 10. The right Y carriage 16 is restrained and supported up and down. Therefore, the sliding resistance of the right Y carriage 16 on the driving side becomes large, but the sliding resistance of the left Y carriage 18 on the driven side can be suppressed to be relatively small accordingly. At this time, by sandwiching the surface plate 10 in the vertical direction on the right Y-carriage 16 on the drive side, the Y-carriage 14 can be corrected in the front-rear direction (swing) in the Y direction, that is, the pitching error, and the Y-carriage 14 It is possible to support almost all of this weight on the drive side portion.

Further, the left Y carriage 18 on the driven side of the three-dimensional coordinate measuring device 1 of the present embodiment is simply based on the upper surface 10T of the surface plate 10 in order to eliminate a rolling error centered on the right Y carriage 16 on the driving side. It will be a supporting role. Therefore, the right Y carriage 16 on the drive side rolls with respect to the surface plate 10 to support the Y carriage 14, but the left Y carriage 18 on the driven side rolls on the upper surface of the surface plate 10 to the extent that the rolling error is alleviated. It is sufficient to lightly support it with only 10T. As a result, no sliding resistance is generated in the left Y carriage 18 on the driven side, and as a result, the rate is controlled by the sliding resistance of the right Y carriage 16 on the driving side, and the yawing error can be suppressed to a small value.

FIG. 18 is a front view (frontal schematic view) showing the appearance of the three-dimensional coordinate measuring device 400 of Comparative Example 2 disclosed in Japanese Patent Application Laid-Open No. 64-035310 or Japanese Patent Application Laid-Open No. 62-235502. .. In the three-dimensional coordinate measuring device 400 of Comparative Example 2, those having the same function or configuration as the three-dimensional coordinate measuring device 1 of the present embodiment are designated by the same reference numerals and the description thereof will be omitted.

As shown in FIG. 18, in the three-dimensional coordinate measuring device 400 of Comparative Example 2, the support portion 50 that supports the right Y carriage 16 on the drive side (the drive unit is not shown) includes an air pad 402R, an air pad 402T, and an air pad 402L. It is supported by the Y guide 42 (surface plate 10) via the air pad 402B and the air pad 402B. The air pad 402R is arranged on the right side surface of the Y guide 42 of the surface plate 10, the air pad 402T is arranged on the upper surface side of the Y guide 42, the air pad 402L is arranged on the left side surface of the Y guide 42, and the air pad 402B is arranged on the left side surface of the Y guide 42. It is arranged on the bottom surface side.

Further, the three-dimensional coordinate measuring device 400 of Comparative Example 2 has a driven-side left Y-carriage 18L and a support portion 50L thereof that follow the driving-side right Y-carriage 16 and move in the Y direction. Here, the left Y carriage 18L and the support portion 50L on the driven side and the right Y carriage 16 and the support portion 50 on the drive side have symmetrical shapes.

A groove 40A and a Y guide 42A are formed on the left end side of the upper surface 10T of the surface plate 10. The grooves 40A and the Y guide 42A and the grooves 40 and the Y guide 42 have symmetrical shapes. Then, the above-mentioned support portion 50L is movably supported by the Y guide 42A along the Y direction.

The driven side support portion 50L is supported by the Y guide 42A (surface plate 10) via the air pad 403T and the air pad 403B. The air pad 403T is arranged on the upper surface side of the Y guide 42A, and the air pad 403B is arranged on the lower surface side of the Y guide 42A. The three-dimensional coordinate measuring device 400 of Comparative Example 2 may have a configuration in which an air pad is arranged on the left side surface side of the Y guide 42A.

In the driven side left Y carriage 18L, when the air pad 403T and the air pad 403B are arranged on the upper and lower surfaces of the Y guide 42A as in the drive side right Y carriage 16, the drive side right Y carriage 16 and the driven side left The sliding resistance increases in both the Y carriage 18L. As a result, in the three-dimensional coordinate measuring device 400 of Comparative Example 2, similarly to the above-mentioned Comparative Example 1, when the Y carriage 14 is moved in the Y direction, the right Y carriage 16 and the left Y carriage 18L are in the Y direction. The yawing error may increase due to the fact that the positional relationship of the carriages is not constant and swings around the Z axis, for example.

Therefore, in order to suppress the yawing error, it is preferable to clearly distinguish between the side that controls the main drive operation and the side that follows the operation, as in the three-dimensional coordinate measuring device 1 of the present embodiment. That is, the right Y carriage 16 on the drive side increases the sliding resistance so as to move along the Y guide 42 as much as possible, while the left Y carriage 18 on the driven side follows the drive side and moves. On the other hand, it is preferable to support it with the minimum amount so that it does not become resistance.

FIG. 19 is a front view (schematic front view) showing the appearance of the three-dimensional coordinate measuring device 500 of Comparative Example 3. In the three-dimensional coordinate measuring device 500 of Comparative Example 3, those having the same function and configuration as the three-dimensional coordinate measuring device 1 of the present embodiment are designated by the same reference numerals and the description thereof will be omitted.

As shown in FIG. 19, the support portion 50 that supports the right Y carriage 16 on the drive side driven in the Y direction by the drive unit 501 is a Y guide 42 (surface plate) via an air pad 502R, an air pad 502T, and an air pad 502L. It is supported by 10). The air pad 502R is arranged on the right side surface of the Y guide 42 of the surface plate 10, the air pad 502T is arranged on the upper surface side of the Y guide 42, and the air pad 502L is arranged on the left side surface of the Y guide 42. The air pads 502R, 502T, and 502L are provided at two positions along the Y direction, respectively.

In the three-dimensional coordinate measuring device 500 of Comparative Example 3, the left Y carriage 18 on the driven side, which follows the right Y carriage 16 on the driving side and moves in the Y direction, slides on the upper surface 10T of the surface plate 10 via the air pad 503T. It is supported freely.

The drive unit 501 is a shaft type linear motor provided on the right side surface of the Y guide 42 (surface plate 10). The drive unit 501 includes a shaft type linear motor mover 501B fixed to the support unit 50, a stator (shaft) 501C arranged parallel to the Y direction, and both ends of the stator 501C on the right side surface of the Y guide 42. It is provided with a fixed portion 501A to be fixed to.

Further, in the three-dimensional coordinate measuring device 500 of Comparative Example 3, scales 112 are provided on the right side surface of the Y guide 42 and the left side surface of the surface plate 10, respectively.

In the three-dimensional coordinate measuring device 500 of Comparative Example 3, the right Y carriage 16 swings around the X axis because the air pad facing the lower surface of the surface plate 10 is not arranged as in Comparative Example 1 described above. Pitching error may occur significantly. Further, as described in Comparative Example 1 described above, the sliding resistances of the right Y carriage 16 and the left Y carriage 18 cannot be balanced on the left and right due to the change due to the pitching error, and the load of the Y carriage 14 becomes the right Y carriage. It is divided into both the 16 and the left Y carriage 18 substantially evenly. As a result, the yawing error may also worsen. Therefore, in order to reduce the pitching error and the yawing error, the upper and lower surfaces of the surface plate 10 are sandwiched between the air pads 62E, 62F, 68E, 68F as in the three-dimensional coordinate measuring device 1 of the present embodiment, and the upper and lower surfaces thereof are sandwiched. It is preferable to provide a drive unit 80 between them.

Further, in the three-dimensional coordinate measuring device 500 of Comparative Example 3, the fixing portion 501A and the stator 501C constituting the driving portion 501 of the shaft type linear motor are provided on the right side surface of the Y guide 42 (surface plate 10). When the fixing portion 501A and the stator 501C are provided on the right side surface of the Y guide 42 (surface plate 10) in this way, an installation error of the fixing portion 501A and the stator 501C with respect to the surface plate 10 may occur, or the respective thermal expansion coefficients may occur. There is a possibility that the fixing portion 501A and the stator 501C may be distorted due to the bimetal effect caused by the difference between the two. In this case, it is difficult to obtain the measurement accuracy based on the surface plate 10. Therefore, it is preferable to provide a drive unit 80 having a roller 84 that abuts on the right side surface of the Y guide 42 (surface plate 10) like the three-dimensional coordinate measuring device 1 of the present embodiment.

Further, in the three-dimensional coordinate measuring device 500 of Comparative Example 3, scales 112 are provided on the right side surface of the Y guide 42 and the left side surface of the surface plate 10, respectively, and the object to be measured is arranged on the upper surface 10T of the surface plate 10. The distance from the measurement area to the scale 112 becomes long. As a result, the difference between the Y coordinate value of the position where the stylus 28 stylus is actually placed and the Y coordinate value of the stylus obtained from the Y coordinate value of the Y carriage 14 actually measured by the scale 112 becomes large. .. Further, the measurement accuracy of the Y coordinate value of the Y carriage 14 is likely to be lowered due to the deflection of the Y carriage 14 in the yawing direction or the like. Further, when the scale 112 is installed on the peripheral edge of the surface plate 10, the scale 112 is easily affected by the ambient temperature because the scale 112 is close to the outside air, and an error due to expansion and contraction of the scale 112 itself is likely to occur.

Therefore, as in the three-dimensional coordinate measuring device 1 of the present embodiment, the scale 112 is provided on the left side surface 40L (see FIG. 3) of the groove 40, and the measurement object is arranged on the upper surface 10T of the surface plate 10. It is preferable to shorten the distance from the scale 112 to the scale 112. By providing the scale 112 on the drive side (right Y carriage 16 side) and near the measurement area, the error can be minimized even if there is a yawing error. When the scale is provided on the left side surface 40L perpendicular to the upper surface 10T, even if dust or dirt falls from above the surface plate 10, it does not get on the scale 112 and is caused by dust or dirt. The reading malfunction of the scale 112 does not occur.

FIG. 20 is a front view (schematic front view) showing the appearance of the three-dimensional coordinate measuring device 1 of the present embodiment. FIG. 21 is a cross-sectional view (cross-sectional schematic view) along the line XXI-XXI in FIG. FIG. 22 is a top view showing the upper surface 10T of the surface plate 10, and is a view showing the arrangement of each air pad provided on the Y carriage 14 and the drive unit 80. The rectangular frame shown by the alternate long and short dash line in FIG. 21 indicates the position of the drive unit 80.

As shown in FIGS. 20 to 22, the three-dimensional coordinate measuring device 1 of the present embodiment has the following differences 1 to 4 with respect to the comparative examples 1 to 3.

As a difference 1, in the three-dimensional coordinate measuring device 1 of the present embodiment, since the rotational moment due to the driving of the driving unit 80 is applied to the Y carriage 14, the upper and lower parts of the portion driven by the driving unit 80 so as to sandwich the driving unit 80. Air pads are placed on the left, right, front and back. As a result, pitching error and rolling error can be reduced.

As a difference 2, in the three-dimensional coordinate measuring device 1 of the present embodiment, the right Y carriage 16 on the driving side and the left Y carriage 18 on the driven side following (following movement) the operation of the right Y carriage 16 are classified. It is made clear (left-right asymmetric structure), and the sliding resistance of the left Y carriage 18 on the driven side is made as small as possible. As a result, when the Y carriage 14 is moved along the Y direction, the swing around the Z axis is suppressed, and the yawing error can be suppressed.

That is, in the three-dimensional coordinate measuring device 1 of the present embodiment, in order to reduce the yawing error, the right Y carriage 16 on the driving side sandwiches the surface plate 10 (Y guide 42) vertically and horizontally. Further, air pads 62E, 64E, 66E, 68E and air pads 62F, 64F, 66F, 68F are arranged before and after the drive unit 80 in the Y direction with the drive unit 80 as the center. Further, the driven side air pad 70 is arranged only on the upper surface side of the surface plate 10 and is arranged between the front and rear intervals of the drive side air pads in the Y direction. As a result, the sliding resistance is concentrated on the drive side, and the driven side is simply supported.

Further, as shown in FIG. 22, the driven air pad 70 is located substantially opposite to the surface plate 10 with respect to the drive unit 80, and is driven by the line LX connecting the driven air pad 70 and the drive unit 80. The line LY connecting the two pairs of air pads existing before and after the portion 80 may be perpendicular to the line LY. From another point of view, it is preferable that the drive unit 80 is provided at the intermediate point between the two pairs of air pads on the drive side, and the driven air pad 70 is also provided at the intermediate point between the two pairs of air pads on the drive side.

As a difference 3, the three-dimensional coordinate measuring device 1 of the present embodiment is provided with a drive unit 80 having a roller 84 that abuts on the right side surface of the Y guide 42 (surface plate 10). As a result, unlike Comparative Example 3, it is possible to prevent an installation error of the drive unit 80 and distortion due to the bimetal effect from occurring in the drive unit 80, so that the measurement accuracy based on the surface plate 10 can be improved. can get.

As a difference 4, in the three-dimensional coordinate measuring device 1 of the present embodiment, the scale 112 is provided on the left side surface 40L of the groove 40, and the measurement area to the scale 112 on the upper surface 10T of the surface plate 10 where the measurement object is arranged. The distance is shortened. Thereby, the measurement accuracy can be improved.

In the above embodiment, the Y guide 42 is formed by the groove 40 formed on the upper surface 10T of the surface plate 10, but the Y guide may be formed by another method.

FIG. 23 is a front schematic view of the three-dimensional coordinate measuring device 1A of another embodiment including the Y guide 42Z different from the above embodiment. As shown in FIG. 23, the right end portion (the end portion facing the right Y carriage 16) of the upper surface 10T of the surface plate 10 is a convex portion provided in a convex shape in the Z direction and has a Y axis. A convex portion extending in the direction is formed. Then, the convex portion forms a Y guide 42Z that movably supports the right Y carriage 16 in the Y-axis direction. The three-dimensional coordinate measuring device 1A has basically the same configuration as the three-dimensional coordinate measuring device 1 of the above embodiment except that the Y guide 42Z is provided.

It is also possible to form the Y guide 42Z by the convex portion in this way. Here, when the Y guide 42Z is made of a material different from that of the surface plate 10, for example, the thermal conductivity of both the surface plate 10 and the Y guide 42Z is different, so that the Y guide 42Z is deformed. There is. Further, if the surface plate 10 is slightly warped, there is a possibility that the measurement based on the surface plate cannot be performed. Therefore, as described in the above embodiment, it is preferable to form the Y guide 42 by the groove 40.

1 ... Three-dimensional coordinate measuring device, 10 ... Surface plate, 10B, 20B, 42B, 202B ... Bottom surface, 10R, 24R, 40R, 42R, 250R ... Right side surface, 10T, 20T, 42T, 202T ... Top surface, 12 ... Carriage, 14 ... Y carriage, 16 ... Right Y carriage, 18 ... Left Y carriage, 20 ... X guide, 20E, 24E, 202E, 250E ... Rear, 20F, 24F, 202F, 250F ... Front, 22 ... Z column, 24 ... Z Carriage, 24L, 40L, 42L, 250L ... Left side, 26 ... Measuring probe, 28 ... Stylus, 40 ... Groove, 40B ... Bottom, 42 ... Y guide, 50, 200 ... Support, 52 ... Base end, 54 ... Right side, 56 ... Left side, 58 ... Tip, 58A ... Support plate, 62E, 62F, 64E, 64F, 66E, 66F, 68E, 68F, 70, 210, 212, 214, 216, 260, 262, 264, 266 ... Air pad, 80, 220, 270 ... Drive unit, 82, 222, 272 ... Motor, 84, 224, 274 ... Roller, 110 ... Linear encoder, 112 ... Scale, 114 ... Optical sensor, 202 ... X guide insertion hole, 250 ... Z carriage insertion hole

Claims (1)

A surface plate on which the object to be measured is placed and
A first strut member having a Y carriage that straddles the surface plate and moves in the Y-axis direction of the surface plate and has a drive mechanism that drives the Y carriage in the Y-axis direction, and the first strut member. A Y carriage having a second support member that follows and moves
A Y guide provided on the side of the first strut member of the surface plate and integrally formed with the surface plate and parallel to the Y-axis direction.
A first both side surface support portion provided on the first strut member and sandwiching both side surfaces of the Y guide to guide the movement of the first strut member in the Y axis direction.
An X guide provided on the Y carriage, and an X guide extending in the X-axis direction across the first strut member and the upper end portion of the second strut member.
An X-axis direction moving mechanism that supports the measuring probe and moves in the X-axis direction along the X guide.
A scale provided on the side of the first strut member and measuring the position of the Y carriage moving in the Y-axis direction.
With
The X-axis direction moving mechanism has a second side surface support portion that sandwiches both side surfaces of the X guide and guides the movement of the X-axis direction moving mechanism in the X-axis direction.
The Y guide is formed on the surface plate with a groove formed on the upper surface of the surface plate as a boundary.
When the region on which the measurement object is placed is defined as the measurement region on the upper surface of the surface plate, the scale is provided on the side surface of the groove on the measurement region side in the inner surface of the groove. 3D coordinate measuring device.

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