JP2018087822A - Three-dimensional coordinates measuring device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a three-dimensional coordinates measuring device for increasing stiffness and reducing vibration generated in movement of a measurement probe.SOLUTION: A three-dimensional coordinates measuring device 1 includes: a surface plate 10 for placing an object to be measured on an upper surface 10T; a portal Y carriage 14 supported by two posts 16, 18 so as to straddle the surface plate; support means for supporting the Y carriage so as to be freely movable in a Y-axis direction; and a measurement probe 26 extended from the Y carriage to the surface plate side. The three-dimensional coordinates measuring device 1 includes drive means that is located at one side of the two posts and moves the Y carriage in a Y-axis direction relative to the surface plate. The support means includes upper-surface-side support means disposed opposite to an upper surface of the surface plate at one side of the two posts and lower-surface-side support means disposed opposite to a lower surface of the surface plate. The drive means is disposed so as to be positioned between the upper-surface-side support means and the lower-surface-side support means in a direction vertical to the upper and lower surfaces of the surface plate.SELECTED DRAWING: Figure 1

Description

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

  In a general three-dimensional coordinate measuring apparatus, a Y carriage that is movable in the front-rear direction (Y-axis direction) is disposed on an upper surface of a surface plate on which a measurement object is placed. The Y carriage has a columnar X guide that extends across the left-right direction (X-axis direction), and the X carriage supports the X carriage so as to be movable in the X-axis direction. A columnar Z carriage along the vertical direction (Z-axis direction) is supported on the X carriage so as to be movable in the Z-axis direction, and a measurement probe is attached to the lower end of the Z carriage. As a result, the probe (stylus) of the measurement probe is supported so as to be movable in the three axial directions of the X, Y, and Z axes (see Patent Document 1, etc.).

JP 2007-33052 A

  By the way, a three-dimensional coordinate measuring apparatus reads the coordinate of the contact point (measurement point) which contacted the measurement probe by making a measurement probe (measurement probe) contact a measurement object. At this time, since the speed at the moment when the measurement probe contacts the contact point is required to be always the same, control is performed so that the movement speed of the measurement probe is constant from slightly before the contact point.

  Therefore, it is important that there is no unevenness in the speed of the measurement probe when the measurement probe is brought into contact with the measurement object at a constant speed.

  Adjustment of the motor control system alone is not sufficient to eliminate such measurement probe speed variations, and vibrations that occur when the measurement probe moves at a speed other than a constant speed become residual vibrations when the probe moves at a constant speed. It is also an important issue to eliminate the influence of remaining. In order to eliminate the residual vibration, the rigidity of the apparatus is increased, that is, the balance of the force applied to the support points during the movement of the Y carriage, the X carriage, and the Z carriage is not lost, or the original is not lost. A quick return to the state is required.

  However, with the increase in measurement speed, the conventional three-dimensional coordinate measuring apparatus has insufficient rigidity, and there is a problem that unevenness occurs in the speed of the measurement probe when the measurement probe is brought into contact with the measurement object at a constant speed. .

  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 measurement apparatus that achieves high rigidity and reduces vibrations that occur when the measurement probe moves.

  In order to achieve the above object, a three-dimensional coordinate measurement apparatus according to one aspect of the present invention is a three-dimensional coordinate measurement apparatus that measures the three-dimensional coordinates of a measurement object by bringing a measurement probe into contact with the measurement object. A movable body that moves while supporting the measurement probe, a guide that guides the movable body in the movement direction of the measurement probe, and one of the movable body and the guide that is formed along the movement direction, and is provided opposite to each other. The first and second guide surfaces, and the first and second support members provided at two locations along the moving direction on the other of the moving body and the guide, and on the first guide surface A drive unit that is provided on the other of the first and second support members that slide and the movable body and the guide, and that abuts the second guide surface and applies a driving force to the movable body in the moving direction; , The first support member and the second with respect to the moving direction And a driving portion abutting the position of the second guide surface is between the supporting member.

  According to this aspect, the vibration generated by the driving force applied from the driving unit to the moving body when the measurement probe moves can be reduced by the first and second support members provided at two locations along the moving direction. it can.

  In the three-dimensional coordinate measuring apparatus according to another aspect of the present invention, the distance in the moving direction between the first support member and the second support member is greater than the distance between the first guide surface and the second guide surface. It can be a large aspect.

  In the three-dimensional coordinate measuring apparatus according to still another aspect of the present invention, a surface plate having an upper surface perpendicular to the Z-axis and a side surface along the Y-axis direction, and a measurement object placed on the upper surface, A groove formed on the upper surface of the board along the Y-axis direction, and a Y guide as a guide formed on the surface plate, the inner side surface of the groove serving as the first guide surface, and the side surface of the surface plate A Y guide having a first guide surface as a second guide surface, and a Y carriage as a moving body guided by the Y guide with the Y-axis direction as a movement direction, and includes first and second support members and a drive unit. And a Y carriage.

  In the three-dimensional coordinate measuring apparatus according to still another aspect of the present invention, a surface plate having an upper surface perpendicular to the Z-axis and a side surface along the Y-axis direction, and a measurement object placed on the upper surface, A Y carriage that moves in the Y axis direction with respect to the board, and an X guide that is provided on the Y carriage and that extends along the X axis direction, and has first and second guide surfaces And an X carriage as a moving body guided by the X guide with the X-axis direction as the moving direction, and an X carriage including first and second support members and a drive unit. Can do.

  In the three-dimensional coordinate measuring apparatus according to still another aspect of the present invention, a surface plate having an upper surface perpendicular to the Z axis and a side surface along the Y axis direction, and a measurement object placed on the upper surface, A Y carriage that moves in the Y-axis direction with respect to the board, and an X carriage that serves as a guide that moves in the X-axis direction with respect to the Y carriage. The X carriage includes first and second support members and a drive unit. A carriage, and a Z carriage as a moving body guided by the X carriage with the Z-axis direction as a movement direction, the Z carriage having first and second guide surfaces extending along the Z-axis direction, It can be set as the aspect provided.

  In the three-dimensional coordinate measuring apparatus according to still another aspect of the present invention, a surface plate having an upper surface perpendicular to the Z-axis and a side surface along the Y-axis direction, and a measurement object placed on the upper surface, A groove formed on the upper surface of the board along the Y-axis direction, and a Y guide as a guide formed on the surface plate, the inner side surface of the groove serving as the first guide surface, and the side surface of the surface plate A Y guide having a first guide surface as a second guide surface, and a Y carriage as a moving body guided by the Y guide with the Y-axis direction as a movement direction, and includes first and second support members and a drive unit. An X guide as a guide provided on the Y carriage and extending along the X-axis direction, the X guide having first and second guide surfaces, and an X-axis direction as a movement direction. An X carriage as a moving body guided by the guide, An X carriage having a second support member and a drive unit, and a Z carriage as a moving body guided by the X carriage with the Z-axis direction as a movement direction, the first carriage extending along the Z-axis direction And a Z carriage having a second guide surface.

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

  According to the present invention, it is possible to achieve high rigidity and to reduce vibration generated when the measurement probe is moved.

The perspective view which showed the external appearance of the three-dimensional coordinate measuring apparatus with which this invention is applied The front view which showed the external appearance of the three-dimensional coordinate measuring apparatus with which this invention is applied Front view with enlarged right side of the surface plate A right side view showing the enlarged right side of the surface plate The perspective view which showed the Y carriage of the state which removed the cover It is the top view which showed the upper surface of the surface plate, and the figure which showed arrangement | positioning with respect to the surface plate of the air pad provided in Y carriage It is the right view which showed the right side of the surface plate, and the figure which showed arrangement | positioning with respect to the surface plate of the air pad provided in 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 The perspective view which showed the support part of Z column removed from X guide The perspective view which showed the support part of Z column removed from 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 at which the X guide supports the X carriage (support portion) from the upper surface side of the surface plate. Schematic diagram showing the positional relationship of the support points at which the X carriage (support section) supports the Z carriage from the right side of the surface plate. Front view showing the appearance of the three-dimensional coordinate measuring apparatus of Comparative Example 1 (front schematic diagram) Sectional drawing along XVIII-XVIII line in FIG. 17 (cross-sectional schematic diagram) Front view showing the appearance of the three-dimensional coordinate measuring apparatus of Comparative Example 2 (front schematic diagram) Front view showing the appearance of the three-dimensional coordinate measuring apparatus 1 of the present embodiment (front schematic diagram) Sectional drawing along XXI-XXI line in FIG. 20 (cross-sectional schematic diagram) It is the top view which showed the upper surface of the surface plate, and the figure which showed arrangement | positioning of each air pad and drive part which were provided in Y carriage Front view showing an external appearance of a three-dimensional coordinate measuring apparatus according to another embodiment (front 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 an appearance of a three-dimensional coordinate measuring apparatus 1 to which the present invention is applied.

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

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

  A lower end portion 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. In addition, a drive unit that contacts 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 drive force of the drive unit. The lower end of the left Y carriage 18 is slidably supported on 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 driven by the drive unit at the lower end of the right Y carriage 16, and the left Y carriage 18 is moved in the Y-axis direction with the driven side.

  A Z column 22 is supported by the X guide 20 so as to be movable along the X guide 20. The Z column 22 has a built-in drive unit that contacts the X guide 20, and moves in the X-axis direction along the X guide 20 by the driving force of the drive unit.

  In addition, a columnar Z carriage 24 extending along the Z axis is supported inside the Z column 22 so as to be movable in the Z axis direction (see FIG. 2). It protrudes from the lower end side of the column 22. The Z column 22 has a built-in drive unit that contacts the Z carriage 24, and the Z carriage 24 moves in the Z-axis direction by the drive 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 measurement probe 26 has, for example, a rod-like stylus 28 having a tip sphere, and the measurement probe 26 is in contact with the measurement target at the tip (tip sphere) of the stylus 28 and the measurement target at the tip of the stylus 28. The amount of displacement of the stylus 28 caused by contact with is detected.

  The three-dimensional coordinate measuring apparatus 1 configured as described above is measured 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 measurement object placed on the upper surface 10T of the surface plate 10. At that time, the position (movement amount) of the Y carriage 14 in the Y axis direction, the position (movement amount) of the Z column 22 in the X axis direction, the position (movement amount) of the Z carriage 24 in the Z axis direction, and the stylus 28. By measuring the position (displacement amount), the three-dimensional coordinates of each position on the surface of the measurement object are measured. Since the processing related to the measurement of the three-dimensional coordinates is well known, detailed description thereof is omitted.

  Next, a Y drive mechanism that supports the Y carriage 14 so as to be movable in the Y-axis direction and moves it in the Y-axis direction will be described.

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

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

  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 along the Y-axis direction is formed near the right side surface 10R of the surface plate 10 and on the upper surface 10T side 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-like covering member such as a metal cover is attached to the front and rear side surfaces of the surface plate 10. FIG. 3 and FIG. 4 show a state in which those 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.

  Accordingly, 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 therebetween, and the lower surface 10B of the surface plate 10 extend along the Y-axis direction. A 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 are not necessarily surfaces perpendicular to the X axis as long as they are surfaces formed along the Y axis direction. The bottom surface 10B of the board 10 and the bottom surface 40B of the groove 40 do not necessarily have to be surfaces perpendicular to the Z axis.

  In the following description, the right side 40R of the groove 40 is the left side 42L of the Y guide 42, the right side 10R of the surface plate 10 is the right side 42R of the Y guide 42, and the top 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 a 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 cover of each part removed. As shown in FIGS. 4 and 5, the lower end of the right Y carriage 16 has a Y-axis direction. A wide support 50 is provided.

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

  3 and 4 show a state where the covering member covering the support portion 50 is removed.

  As shown mainly in FIG. 3, the support portion 50 is opposed to the upper surface 42 </ b> T of the Y guide 42 and is disposed along a direction (horizontal direction) orthogonal to the Z axis, and a base end portion 52. A right side portion 54 extending in the Z-axis direction and disposed on the side facing the right side surface 42R of the Y guide 42, and a left side surface 42L of the Y guide 42 extending in the Z-axis direction from the base end portion 52. And a left side portion 56 disposed on the opposite side.

  In addition, 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 a front end portion 58 of the support portion 50 at the lower end portion of the right side portion 54.

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

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

  In these drawings, two air pads 62F and 62E arranged along the upper surface 42T of the Y guide 42 are arranged at two locations along the Y-axis direction (on a straight line parallel to the Y-axis) at the base end portion 52 of the support portion 50. Are disposed at a position facing the upper surface 42T of the Y guide 42 and facing downward.

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

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

  Two air pads 68F and 68E (see FIGS. 3 and 7) arranged along the lower surface 42B of the Y guide 42 are arranged at two locations along the Y-axis direction (parallel to the Y-axis) at the distal end portion 58 of the support portion 50. 2 positions on the straight line), and is arranged facing the lower surface of the Y guide 42 and facing upward.

  The air pad 70 disposed 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 disposed downward facing the upper surface 10T of the surface plate 10.

  Here, in each of the base end portion 52, the right side portion 54, the left side portion 56, and the distal end portion 58 of the support portion 50, the air pads 62F, 64F, 66F, and 68F installed on the front side (front side) are in the Y-axis direction. The air pads 62E, 64E, 66E, and 68E that are disposed at substantially the same position with respect to (that is, disposed at positions along the same XZ plane) and disposed on the rear side (rear side) are substantially at the same position with respect to the Y-axis direction. 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 distal 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 a Y-axis position that is the center of gravity of all members (Y carriage 14 and Z column 22) that move in the Y-axis direction together with the Y carriage 14. It is arranged at a position substantially coincident with the direction position.

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

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

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

  Further, each air pad 62F, 62E, 64F, 64E, 66F, 66E, 68F, 68E, 70 is ejected from the air pad 62F, so that each air pad 62F, 62E, 64F, 64E, 66F of the support unit 50 in the right Y carriage 16 is ejected. 66E, 68F, 68E are slidable in the Y-axis direction with respect to the Y guide 42, and the air pad 70 in the left Y carriage 18 is slidable with respect to the upper surface 10T of the surface plate 10.

  Accordingly, the Y carriage 14 is movable in the Y axis direction with respect to the surface plate 10.

  Next, the drive means for the Y carriage 14 in the Y drive mechanism will be described.

  As shown in FIG. 4, the 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 disposed at a position that is substantially in the middle between the two air pads 64 </ b> F and 64 </ b> E provided on the right side portion 54 of the support unit 50.

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

  The drive unit 80 is configured integrally with a motor 82, a rotatable roller 84, and a speed reduction mechanism that couples them so as to be able to transmit power. The drive unit 80 is integrally configured. Rotate.

  As shown in FIG. 6, the drive unit 80 includes 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 approximately in the middle between the two air pads 64F and 64E. The right side surface 42 </ b> R (the right side surface 10 </ b> R of the surface plate 10) is placed on the right side portion 54 of the support portion 50.

  Therefore, by driving the motor 82 of the drive unit 80 and rotating 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 a driving unit for the Y carriage 14, in addition to the driving unit 80, a driving unit that abuts on the left side surface 42 </ b> L of the Y guide 42 may be provided, for example, facing the driving unit 80. Only the drive unit that contacts the left side surface 42L of the guide 42 may be provided.

  Next, the position detection unit of the Y carriage 14 in the Y drive mechanism will be described.

  FIG. 8 is an enlarged front view 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-like scale 112 constituting an optical linear encoder 110, which is provided with a grid scale, is installed along the Y-axis direction. Is 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 provided with a support member and is disposed at a position facing the scale 112. Then, a detection signal resulting from the lattice scale of the scale 112 formed at a position facing the optical sensor 114 is output from the optical sensor 114.

  According to this 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 supports the Z column 22 so as to be movable in the X-axis direction and moves it in the X-axis direction will be described.

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

  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 drawings, the Z column 22 is a support portion 200 to which various components are assembled, and includes a support portion 200 corresponding to an X carriage. The support portion 200 includes 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 obtained by jetting air 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 defines the X guide insertion hole 202. A disk-shaped air pad that can slide with respect to 20 is provided.

  On the front surface 202F of the X guide insertion hole 202, as shown in FIG. 10, a total of four air pads 210, 210, 210, 210 are arranged, one at each of four locations that are symmetrical vertically and horizontally. 20 is disposed rearwardly facing the front surface 20F (see FIG. 5).

  On the rear surface 202E of the X guide insertion hole 202, as shown in FIG. 11, a total of three air pads 212, 212, 212 are arranged, one at each of the upper two places and the lower one place. The rear surface 20E (see FIG. 5) is disposed facing forward.

  On the upper surface 202T of the X guide insertion hole 202, as shown in FIG. 9, a total of two air pads 214, 214, one at each of the two left and right sides, are arranged, and the upper surface 20T of the X guide 20 (see FIG. 5). It is arrange | positioned facing down.

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

  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 is interposed via the air pads 210, 212, 214, and 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, and 216, the air pads 210, 212, 214, and 216 of the support unit 200 can slide in the X-axis direction with respect to the X guide 20. .

  Therefore, the Z column 22 is movable in the X-axis direction.

  Next, the drive means for the Z column 22 in the X drive 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 above the rear surface 202E of the X guide insertion hole 202. It is installed so as to come into contact with the rear surface 20E (see FIG. 5) of the X guide 20 at a position approximately in the middle between the two installed air pads 212, 212.

  Therefore, by driving the motor 222 of the drive unit 220 and rotating 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 unit 200 are provided with optical linear encoders similar to the linear encoder 110 described above in the Y drive mechanism as position detection means for the Z column 22 in the X drive mechanism. The long plate-like scale is installed along the X-axis direction, and the optical sensor is disposed on the support portion 200 at a position facing the scale.

  Next, a Z drive mechanism that supports the Z carriage 24 so as to be movable in the Z-axis direction and moves it in the Z-axis direction will be described.

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

  FIGS. 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. As shown in these drawings, the support portion 200 is shown. A rectangular Z-carriage insertion hole 250 is provided on the front side of the X guide insertion hole 202 along the Z-axis direction through which the quadrangular prism-shaped Z carriage 24 is inserted.

  In the support portion 200, 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) that defines the Z carriage insertion hole 250 has air (see FIG. 13). Is provided with an air pad that is slidable with respect to the Z carriage 24.

  In the vicinity of the lower opening of the Z carriage insertion hole 250, a total of four air pads, one on each of the front surface 250F, the rear surface 250E, the right side surface 250R, and the left side surface 250L of the Z carriage insertion hole 250, as shown in FIG. 260, 262, 264, and 266 are arranged, and each of the air pads 260, 262, 264, and 266 is disposed on 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. Opposite to the rear, forward, left, right.

  In the vicinity of 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 surface 250F, the rear surface 250E, and the right side surface 10R of the Z carriage insertion hole 250. The air pads 260, 262, and 264 are disposed rearward, forward, and leftward to face the front surface 24F, the rear surface 24E, and the right side surface 24R of the Z carriage 24, respectively.

  On the other hand, two air pads 266 and 266 are disposed 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 are opposed to the left side surface 24L of the Z carriage 24. And placed rightward.

  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 is interposed via the air pads 260, 262, 264, and 266. The Z carriage 24 is supported.

  Further, by ejecting air from the air pads 260, 262, 264, 266, the air pads 260, 262, 264, 266 of the support unit 200 can slide with respect to the Z carriage 24, and the Z carriage 24 can be The state is movable in the Z-axis direction.

  Next, the drive means for the Z carriage 24 in the Z drive mechanism will be described.

  As shown in FIGS. 12 and 13, the front surface 250 </ b> F 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. Further, it is installed so as to come into contact with the front surface 24F of the Z carriage 24 at a position approximately in the middle between the two air pads 260, 260.

  Therefore, by driving the motor 272 of the drive unit 270 and rotating 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 unit 200 are provided with optical linear encoders similar to the linear encoder 110 described above in the Y drive mechanism as position detection means for the Z carriage 24 in the Z drive mechanism. The long plate-like scale is installed along the Z-axis direction, and the optical sensor is disposed on the support portion 200 at a position facing the scale.

  9 to 13 is a bendable guide member that guides the cable through the cable. The cable of the measurement probe 26 attached to the lower end of the Z carriage 24 is inserted into the Z carriage 24 and the cable protection tube 278 inside the Z column 22 to prevent interference with other members. .

  The vibration reduction effect (high rigidity) in the three-dimensional coordinate measuring apparatus 1 configured as described above will be described.

  First, the vibration reduction effect of the Y carriage 14 in the Y drive mechanism will be described.

  FIG. 14 is a schematic diagram showing the positional relationship between the support points at which 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. As shown in FIG.

  In the figure, 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 positions where the air pads 66F and 66E of the Y carriage 14 (support portion 50) abut. The two front and rear support points P3 and P4 existing on the right side 42R of the Y guide 42 indicate positions where the air pads 64F and 64E of the Y carriage 14 (support 50) come into contact, and exist on the right side 42R of the Y guide 42. The support point P0 to indicate the position where the roller 84 of the drive unit 80 of the Y carriage 14 (support unit 50) contacts (see FIG. 6). The support point (P0) to which the driving force is applied is referred to as the driving point (P0) (the same applies hereinafter).

  Support points P1 and P2 indicate fixed support points, and support points P3 and P4 indicate auxiliary support points. That is, the air pads 66F and 66E serving as 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, in the support portion 50 of the Y carriage 14. Supported by On the other hand, the air pads 64F and 64E serving as the auxiliary support points P3 and P4 are 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 a guide surface on which they slide. It is supported so as to be able to move forward and backward, and is urged in a direction to contact the right side surface 42R.

  As shown in the figure, the support point P1 and the support point P3, and the support point P2 and the support point P4 are arranged at positions facing each other with the Y guide 42 therebetween. That is, the positions of the support point P1 and the support point P3 in the Y-axis direction and the Z-axis direction substantially coincide, and the positions of the support point P2 and the support point P4 in the Y-axis direction and the Z-axis direction substantially coincide.

  The drive point P0 is disposed between the support point P3 and the support point P4 with respect to the Y-axis direction, which is the moving direction of the Y carriage 14, that is, at a substantially intermediate position between the support point P1 and the support point P2. The driving point P0 may be arranged at a position other than the intermediate position as long as it is in a range between the supporting point P1 and the supporting point P2.

  According to such an arrangement of the support points, the support points P3 and P4 are used as auxiliary support points, and three driving points P0 on the right side 42R and two support points P1 and P2 on the left side 42L are provided. In this state, the Y carriage 14 is supported, and the rotation of the Y carriage 14 around the Z axis around the drive point P0 is restricted.

  In particular, the distance (interval) in the Y-axis direction between the support point P1 and the support point P2 is sufficiently larger than the distance (interval) in the X-axis direction between the drive point P0 and the support points P1 and P2, and the Y carriage 14 Even during acceleration / deceleration, the balance of the force applied to each support point is not easily lost.

  That is, when the distance between the support point P1 and the support point P2 in the Y-axis direction is narrow, an external force (force perpendicular to the drive direction) generated when driven at the drive point P0 is formed in the air pads 66F and 66E. It becomes easy to crush a thin air layer. When the air layer is crushed, its springy reaction force is generated and vibration is generated. In the present embodiment, the distance between the support point P1 and the support point P2 in the Y-axis direction is sufficiently wider than the distance between the opposing drive points P0, and thus the external force applied to the support points P1 and P2 is small. The structure is less prone to vibration.

  Therefore, the Y carriage 14 is less likely to vibrate (sway) in the direction around the Z axis due to the driving force applied to the Y guide 42 from the driving point P0 when the Y carriage 14 moves in the Y axis direction. That is, when the Y carriage 14 moves, the yawing error that causes the left and right directions to swing with respect to the traveling direction is small, and the vibration is also small.

  The distance (interval) in the Y-axis direction between the support point P1 and the support point P2 is the distance (interval) in the X-axis direction between the drive point P0 and the support points P1 and P2, that is, the right side surface 42R of the Y guide 42. Although it is desirable that the distance is greater than the distance between the left side surface 42L and the left side surface 42L, the distance is not necessarily limited thereto.

  Further, the groove 40 is formed in the surface plate 10 and a part of the area along the right side surface 10R of the surface plate 10 is used as the Y guide 42, and the left and right side surfaces of the surface plate 10 are used as the Y guide. In comparison, the distance (interval) between the drive point P0 and the support points P1 and P2 is small. When the distance between the drive point P0 and the support points P1 and P2 is large, the natural frequency is low and a swing with a large amplitude occurs in the Y carriage 14. However, as in the present embodiment, the drive point P0 and the support point P1. Since the distance (interval) with P2 is small, the natural frequency becomes high, and the amplitude can be reduced even when the Y carriage 14 is shaken accordingly.

  From the above, the vibration of the Y carriage 14 when the Y carriage 14 moves in the Y-axis direction is reduced, and the vibration of the measurement probe 26 (stylus 28) when the measurement probe 26 moves in the Y-axis direction is reduced. The

  Note that the side surface (guide surface) of the Y guide 42 on which the drive point P0, the support points P1, P2, and the support points P3, P4 are arranged is not limited to the present embodiment, and the Y guide 42 has an arbitrary direction opposite to each other. The support points P1 and P2 are disposed on one guide surface of the two side surfaces (guide surfaces), and the drive point P0 and the support points P3 and P4 are disposed on the other guide surface.

  Next, the vibration reduction effect of the support unit 200 (X carriage) in the X drive mechanism will be described.

  FIG. 15 is a schematic diagram showing the positional relationship between the support points at which the X guide 20 supports the support portion 200 corresponding to the X carriage from the upper surface 10T side of the surface plate 10 (the upper surface 20T side of the X guide 20).

  In the drawing, two left and right support points P1, P2 existing on the front surface 20F of the X guide 20 are two air pads 210, 210 installed on the upper portion of the support portion 200 (above the front surface 202F of the X guide insertion hole 202). The left and right support points P3 and P4 existing on the rear surface 20E of the X guide 20 are installed on the upper portion of the support portion 200 (above the rear surface 202E of the X guide insertion hole 202). The driving point P0 present on the rear surface 20E of the X guide 20 is indicated by the roller 224 (see FIG. 11) of the driving unit 220 of the support unit 200. The abutting position is shown.

  Support points P1 and P2 indicate fixed support points, and support points P3 and P4 indicate auxiliary support points. The structural differences between the fixed support point and the auxiliary support point are as described above.

  As shown in the figure, the support point P1 and the support point P3, and the support point P2 and the support point P4 are arranged at positions facing each other with the X guide 20 therebetween. That is, the positions of the support point P1 and the support point P3 in the X-axis direction and the Z-axis direction substantially coincide, and the positions of the support point P2 and the support point P4 in the X-axis direction and the Z-axis direction substantially coincide.

  The drive point P0 is disposed between the support point P3 and the support point P4, that is, at a substantially intermediate position between the support point P1 and the support point P2, with respect to the X-axis direction that is the moving direction of the support unit 200. The driving point P0 may be arranged at a position other than the intermediate position as long as it is in a range between the supporting point P1 and the supporting point P2.

  According to such an arrangement of the support points, similarly to the arrangement of the support points in the Y drive mechanism described with reference to FIG. 14, the support points P3 and P4 are used as auxiliary support points, and one drive point P0 on the rear surface 20E is obtained. The support portion 200 is supported at the three support points P1 and P2 on the front surface 20F, and the rotation of the support portion 200 around the Z axis around the drive point P0 is restricted.

  In particular, the distance (interval) in the X-axis direction between the support point P1 and the support point P2 is sufficiently larger than the distance (interval) in the Y-axis direction between the drive point P0 and the support points P1 and P2, and the support unit 200 Even during acceleration / deceleration, the balance of the force applied to each support point is not easily lost.

  Therefore, it is possible to reduce the vibration (swaying) of the support portion 200 in the direction around the Z axis due to the driving force applied to the X guide 20 from the drive point P0 when the support portion 200 moves in the X axis direction. That is, when the support unit 200 moves, the yawing error that causes the left and right directions to swing with respect to the traveling direction is small, and the vibration is also small.

  The distance (interval) in the X-axis direction between the support point P1 and the support point P2 is the distance (interval) in the Y-axis direction between the drive point P0 and the support points P1 and P2, that is, the front surface 20F of the X guide 20. Although it is desirable that the distance is larger than the distance to the rear surface 20E, the distance is not necessarily limited thereto. In the present embodiment, the distance (interval) in the X-axis direction between the support point P1 and the support point P2 is at least larger than the width of the Z carriage 24 (the distance between the right side surface 24R and the left side surface 24L of the Z carriage 24). Thus, the distance (interval) in the X-axis direction between the support point P1 and the support point P2 is increased.

  From the above, the vibration of the support portion 200 when the support portion 200 corresponding to the X carriage moves in the X-axis direction is reduced, and the measurement probe 26 (stylus 28) when the measurement probe 26 moves in the X-axis direction. Vibration is reduced.

  Note that the side surface (guide surface) of the X guide 20 on which the drive point P0, the support points P1, P2, and the support points P3, P4 are arranged is not limited to the present embodiment, and the X guide 20 may be in any direction opposite to each other. The support points P1 and P2 are disposed on one guide surface of the two side surfaces (guide surfaces), and the drive point P0 and the support points P3 and P4 are disposed on the other guide surface.

  Next, the vibration reduction effect of the Z carriage 24 in the Z drive mechanism will be described.

  16 shows the positional relationship between the support points at which the support unit 200 supports the Z carriage 24 (support points at which the Z carriage 24 is supported by the support unit 200) on the right side surface 10R side of the surface plate 10 (the right side surface of the Z carriage 24). It is the schematic diagram shown from the 24R side.

  In the drawing, two upper and lower support points P1 and P2 existing on the front surface 24F of the Z carriage 24 are two air pads 260 and 260 (FIG. 12, FIG. 12) installed on the support portion 200 (the front surface 250F of the Z carriage insertion hole 250). The upper and lower two support points P3 and P4 existing on the rear surface 24E of the Z carriage 24 are two air pads installed on the support portion 200 (the rear surface 250E of the Z carriage insertion hole 250). 262 and 262 (see FIGS. 12 and 13) indicate positions where the roller 274 (see FIG. 13) of the driving unit 270 of the support unit 200 contacts the driving point P0 existing on the front surface 24F of the Z carriage 24. Indicates the position.

  Support points P1 and P2 indicate fixed support points, and support points P3 and P4 indicate auxiliary support points. The structural differences between the fixed support point and the auxiliary support point are as described above.

  As shown in the figure, the support point P1 and the support point P3, and the support point P2 and the support point P4 are arranged at positions facing each other with the Z carriage 24 therebetween. That is, the positions of the support point P1 and the support point P3 in the X-axis direction and the Z-axis direction substantially coincide, and the positions of the support point P2 and the support point P4 in the X-axis direction and the Z-axis direction substantially coincide.

  The drive point P0 is disposed between the support point P3 and the support point P4 with respect to the Z-axis direction, which is the moving direction of the Z carriage 24, that is, at a substantially intermediate position between the support point P1 and the support point P2. The driving point P0 may be arranged at a position other than the intermediate position as long as it is in a range between the supporting point P1 and the supporting point P2.

  According to such an arrangement of the support points, similarly to the arrangement of the support points in the Y drive mechanism described with reference to FIG. 14, the support points P3 and P4 are used as auxiliary support points, and one drive point P0 on the front surface 24F The Z carriage 24 is supported at the three support points P1 and P2 on the rear surface 24E, and the rotation of the Z carriage 24 around the X axis around the drive point P0 is restricted.

  In particular, the distance (interval) between the support point P1 and the support point P2 in the Z-axis direction is sufficiently larger than the distance (interval) between the drive point P0 and the support points P1 and P2 in the Y-axis direction. Even during acceleration / deceleration, the balance of the force applied to each support point is not easily lost.

  Therefore, the Z carriage 24 is less likely to vibrate (sway) in the direction around the X axis due to the driving force applied to the Z carriage 24 from the driving point P0 when the Z carriage 24 moves in the Z axis direction. That is, when the Z carriage 24 moves, the yawing error that causes the left and right directions to swing with respect to the traveling direction is small, and the vibration is also small.

  The distance (interval) in the Z-axis direction between the support point P1 and the support point P2 is the distance (interval) in the Y-axis direction between the drive point P0 and the support points P1 and P2, that is, the front surface 24F of the Z carriage 24. Although it is desirable that the distance is larger than the distance to the rear surface 24E, the distance is not necessarily limited thereto.

  Conventionally, the belt tip is fixed at a position shifted in the Y-axis direction from the axial center position of the Z carriage 24, and the Z carriage 24 is moved in the Z-axis direction by moving the belt up and down. In this case, a moment is applied in the direction around the X axis when the Z carriage 24 moves in the Z axis direction. On the other hand, in the present embodiment, since the drive point P0 is disposed facing the fixed support points P1 and P2, such a moment is generated in the movement of the Z carriage 24 in the Z-axis direction. This structure is not applied, and the vibration of the Z carriage 24 in the direction around the X axis is reduced.

  From the above, vibration of the Z carriage 24 when the Z carriage 24 moves in the Z-axis direction is reduced, and vibration of the measurement probe 26 (stylus 28) when the measurement probe 26 moves in the Z-axis direction is reduced. The

  The side surface (guide surface) of the Z carriage 24 on which the drive point P0, the support points P1 and P2, and the support points P3 and P4 are arranged is not limited to the present embodiment, and the Z carriage 24 may be in any direction opposite to each other. The support points P1 and P2 are disposed on one guide surface of the two side surfaces (guide surfaces), and the drive point P0 and the support points P3 and P4 are disposed on the other guide surface.

  As described above, the vibration reduction effect of the Y drive mechanism, the X drive mechanism, and the Z drive mechanism reduces the vibration when the measurement probe 26 (stylus 28) moves in the three-axis directions of the X, Y, and Z axes. Therefore, when the stylus 28 is brought into contact with the measurement object at a constant speed, it is possible to appropriately reduce a situation in which unevenness occurs in the speed of the stylus 28 due to vibration (residual vibration) generated by the previous movement.

  As described above, the three-dimensional coordinate measuring apparatus 1 according to the above embodiment may have a configuration in which left and right are reversed, and the groove 40 and the Y guide 42 are not positioned along the right side surface 10R of the surface plate 10, but the surface plate. You may form in the position along 10 left side surfaces.

  Moreover, although the case where an air pad (air bearing) was used as a supporting member that slidably contacts each surface of the Y guide 42 and the like has been described in the above embodiment, a type of supporting member other than an air pad may be used. Good.

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

  In the three-dimensional coordinate measuring apparatus 1 of the above embodiment, the axis of the roller 84 of the driving unit 80 is arranged in the direction perpendicular to the upper surface 10T of the surface plate 10. Therefore, since the roller 84 comes into contact with 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.

  The roller 84 is driven along the side surface (the 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 reference to the surface plate 10. If the roller 84 moves along another rail different from the surface plate 10, it does not synchronize with the deformation of the surface plate 10 due to other factors such as thermal expansion of the other rail.

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

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

  Further, in the Y carriage 14, the support unit 200, or the Z carriage 24 that is a moving body, the distance (interval) between the support point P1 and the support point P2 is the distance between the support points P1 and P2 and the drive point P0 ( Large enough for (interval). Therefore, it is possible to reduce the vibrations of these moving bodies, and it is possible to reduce yawing errors in which the moving direction swings left and right with respect to the moving direction.

  Further, the air pads 66F and 66E are arranged in a manner 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, P2 by the air pads 66F, 66E as the side surfaces of the groove 40 of the surface plate 10, it follows the deformation of the surface plate 10 such as thermal expansion, Measurements can be made with reference to the surface plate 10.

  Further, air pads 66F and 66E facing the support points P3 and P4 by the air pads 64F and 64E are present 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 by them. Therefore, the side surface of the surface plate 10 is used as a reference, and the Y carriage 14 is supported only on the driving side (the right Y carriage 16 side where the driving unit 80 is disposed) with respect to the driven side (the left Y carriage 18 side). . Therefore, the sliding resistance on the driven side is negligible, and the yawing error is greatly reduced.

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

  Further, the position of the air pad 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 is the air pads 66F and 66E (support points P1 and P2) on the driving side of the Y carriage 18 or the air pads 64F and 64E. Exists between (support points P3, P4). Therefore, even in sudden acceleration / deceleration, there is almost no sliding resistance just by receiving the moments of the X guide 20 and the measuring section within the width of the support points P1, P2 (or support points P3, P4). As a result, vibration and yawing errors are extremely small.

  Next, the three-dimensional coordinate measuring apparatus 1 of the present embodiment and the three-dimensional coordinate measuring apparatuses of Comparative Examples 1 and 2 will be compared to describe the effects of the three-dimensional coordinate measuring apparatus 1 of the present embodiment in more detail. In addition, this invention is not limited to description of the following effects.

  FIG. 17 is a front view (front schematic view) showing the appearance of the three-dimensional coordinate measuring apparatus 300 of Comparative Example 1 disclosed in Japanese Patent Laid-Open No. 5-31556. 18 is a cross-sectional view (schematic cross-sectional view) taken along line XVIII-XVIII in FIG. Note that in the three-dimensional coordinate measuring apparatus 300 of the comparative example 1, the same reference numerals are given to the same functions or configurations as those of the three-dimensional coordinate measuring apparatus 1 of the present embodiment, and the description thereof is omitted.

  As shown in FIGS. 17 and 18, in the three-dimensional coordinate measuring apparatus 300 of Comparative Example 1, the support unit 50 that supports the right Y carriage 16 on the side directly driven by the drive unit 301 (hereinafter referred to as drive side). Is supported by the surface plate 10 via the air pad 302R and the air pad 302T. The air pad 302R is disposed on the right side surface of the surface plate 10, and the air pad 302T is disposed on the right end side of the upper surface 10T of the surface plate 10. Air pads 302T are provided at two positions along the Y direction (see FIG. 18).

  On the other hand, in the three-dimensional coordinate measuring apparatus 300 of the first comparative example, the left Y carriage 18 on the driven side (hereinafter referred to as the driven side) that moves in the Y direction following the right Y carriage 16 on the driving side 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 disposed on the upper surface 10T of the surface plate 10. The left Y carriage 18 has a support portion 18a facing the left side surface of the surface plate 10 at the lower end thereof, and the air pad 303T is arranged on the left side surface of the surface plate 10 by the support portion 18a.

  The drive unit 301 has basically the same configuration as the drive unit 80 of this embodiment, for example, and is provided in the vicinity of the air pad 302R. A rectangular frame represented by a two-dot chain line in FIG. 18 indicates the position of the drive unit 301.

  In the three-dimensional coordinate measuring apparatus 300 of Comparative Example 1, air pads 302R and air pads 303L are arranged on both side surfaces (vertical surfaces on both sides) in FIG. In this case, it seems that the Y carriage 14 is seemingly stable when moving back and forth in the Y direction, but the yawing error increases when the Y carriage 14 moves back and forth in the Y direction.

  That is, when the air pad 302R and the air pad 303L are arranged on both side surfaces of the surface plate 10, the driving side right Y carriage 16 and the driven side left Y carriage 18 control the main driving operation and the operation thereof. The distinction from the following side is not clear, and both have the same sliding resistance. As a result, when the Y carriage 14 is moved in the Y direction, the positional relationship in the Y direction between the right Y carriage 16 and the left Y carriage 18 is not constant. For example, the yawing is performed by swinging around the Z axis. The error increases. Therefore, as in the present embodiment, it is preferable that the right Y carriage 16 on the driving side is moved along the Y guide 42 (see FIG. 3) and the sliding resistance of the driven left Y carriage 18 is as small as possible. Since the left Y carriage 18 moves following the right Y carriage 16 on the driving side, the above-described oscillation around the Z axis does not occur.

  In the three-dimensional coordinate measuring apparatus 300 of Comparative Example 1, the drive unit 301 is not disposed in the vicinity of the driven air pad 303L. Further, the driven air pad 303L is located with respect to the driving air pad 302R. 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 driven air pad 303L is located on the opposite side of the surface plate 10 and away from the drive unit 301, the drive unit 301 is supported by the sliding of 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 a direction perpendicular to the pressing direction of the surface plate 10 (Y direction) in a state where the air pad 302R and the air pad 303L are pressed from both sides so as to sandwich both side surfaces of the surface plate 10. In this case, the yawing error is remarkably deteriorated as the balance of the sliding resistance during the moving operation is slightly lost.

  As a method for reducing such a yawing error, for example, Japanese Patent Laid-Open No. 7-218247 discloses that the Y carriage 14 is prevented from being twisted and bent even when the Y carriage 14 is moved in the Y direction with a large acceleration. It is disclosed to provide a drive with a special structure possible. However, when such a specially structured drive unit is employed, there is a problem that the three-dimensional coordinate measuring apparatus 300 is enlarged and the structure of the drive unit is complicated. Therefore, the three-dimensional coordinate measuring apparatus 300 of Comparative Example 1 has a problem that a yawing error occurs when the Y carriage 14 moves.

  Further, in the three-dimensional coordinate measuring apparatus 300 of the comparative example 1, although 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, the present embodiment shown in FIG. Unlike the three-dimensional coordinate measuring apparatus 1, no air pad is arranged on the lower surface side of the surface plate 10. That is, since the three-dimensional coordinate measuring apparatus 300 of Comparative Example 1 is not provided with an air pad that faces the lower surface of the surface plate 10 or a Y guide (not shown) provided on the surface plate 10, Only the upper surface of the surface plate 10 determines the position of the right Y carriage 16 in the vertical direction (Z-axis direction). For this reason, in the three-dimensional coordinate measuring apparatus 300 of the comparative example 1, a pitching error becomes a problem in addition to a yawing error.

  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 becomes important. For example, in the three-dimensional coordinate measuring apparatus 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 instantaneously moves with the upper surface 10T of the surface plate 10 as a fulcrum. It tilts (oscillates) around the X axis. For this reason, when the right Y carriage 16 on the driving side is supported only on the surface plate 10 as in the three-dimensional coordinate measuring apparatus 300 of the comparative example 1, the supporting point is only one point in the vertical direction, When driven by the drive unit 301, a rotational moment works with a 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 significant.

  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 this time, the right Y carriage 16 and the left Y carriage 18 have an asymmetric structure, and the sliding resistance of the driving side right Y carriage 16 is preferably larger than that of the driven side left Y carriage 18. Therefore, the sliding resistance cannot be balanced on the left and right due to the change due to the pitching error. For this reason, the Y carriage 14 is further deformed so as to be largely twisted. As a result, the yawing error may be deteriorated.

  Further, when the air pad 302T is disposed on the upper surface side of the surface plate 10 as in the three-dimensional coordinate measuring apparatus 300 of the comparative example 1, but the air pad is not disposed on the lower surface side, the load on the Y carriage 14 is The Y carriage 16 and the driven left Y carriage 18 are equally divided equally. 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, yawing error increases.

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

  In the three-dimensional coordinate measuring apparatus 300 of Comparative Example 1, no air pad is provided on the lower surface of the surface plate 10 and only one point is supported on the right Y carriage 16 in the vertical direction. There is a possibility that not only the pitching error but also the swing of the right Y carriage 16 around the Y axis, that is, the rolling error may occur. Even when such a rolling error occurs, the balance of sliding resistance cannot be achieved on the left and right in the same way as when a pitching error occurs, which may lead to a deterioration in yawing error.

  On the other hand, in the right Y carriage 16 of the three-dimensional coordinate measuring apparatus 1 of the present embodiment, the air pads 62E, 62F, 68E, and 68F (see FIG. 7) are pressed not only from the upper surface side but also from the lower surface side. Thus, the right Y carriage 16 is restrained and supported in the vertical direction. For this reason, although the sliding resistance of the right Y carriage 16 on the driving side increases, the sliding resistance of the left Y carriage 18 on the driven side can be kept relatively small. At this time, by sandwiching the surface plate 10 in the vertical direction on the right Y carriage 16 on the driving side, the Y carriage 14 can be corrected for forward / backward tilting (swing) in the Y direction and the weight applied to the Y carriage 14 on the driving side. It becomes possible to support almost at the part.

  Further, the driven left Y carriage 18 of the three-dimensional coordinate measuring apparatus 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 around the right Y carriage 16 on the driving side. Become a supporting role. For this reason, the right Y carriage 16 on the driving 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 has an upper surface of the surface plate 10 to such an extent that the rolling error is reduced. It only needs to be lightly supported by 10T alone. As a result, no sliding resistance is generated in the driven left Y carriage 18, and as a result, the speed is controlled by the sliding resistance of the right Y carriage 16 on the driving side, and the yawing error can be suppressed small.

  FIG. 19 is a front view (front schematic view) showing the appearance of the three-dimensional coordinate measuring apparatus 500 of Comparative Example 2. Note that in the three-dimensional coordinate measuring apparatus 500 of the comparative example 2, the same reference numerals are given to the same functions and configurations as those of the three-dimensional coordinate measuring apparatus 1 of the present embodiment, and the description thereof is omitted.

  As shown in FIG. 19, the support unit 50 that supports the drive-side right Y carriage 16 driven in the Y direction by the drive unit 501 includes a Y guide 42 (surface plate) via an air pad 502R, an air pad 502T, and an air pad 502L. 10). The air pad 502R is disposed on the right side surface of the Y guide 42 of the surface plate 10, the air pad 502T is disposed on the upper surface side of the Y guide 42, and the air pad 502L is disposed 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 apparatus 500 of Comparative Example 2, the driven left Y carriage 18 that moves in the Y direction following the driving right Y carriage 16 slides on the upper surface 10T of the surface plate 10 via the air pad 503T. It is supported movably.

  The drive unit 501 is a shaft-type linear motor provided on the right side surface of the Y guide 42 (the 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 in parallel to the Y direction, and both ends of the stator 501C on the right side of the Y guide 42. And a fixing portion 501A to be fixed to.

  In the three-dimensional coordinate measuring apparatus 500 of Comparative Example 2, the 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 apparatus 500 of the comparative example 2, 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 the comparative example 1. Pitching errors may occur significantly. As described in the first comparative example, the sliding resistance balance between 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 is increased by the right Y carriage. 16 and the left Y carriage 18 are equally divided equally. As a result, the yawing error may be deteriorated. Therefore, in order to reduce the pitching error and yawing error, the upper and lower surfaces of the surface plate 10 are sandwiched between the air pads 62E, 62F, 68E, and 68F as in the three-dimensional coordinate measuring apparatus 1 of the present embodiment, and It is preferable to provide the drive part 80 between them.

  Further, in the three-dimensional coordinate measuring apparatus 500 of Comparative Example 2, the fixed portion 501A and the stator 501C constituting the drive unit 501 of the shaft type linear motor are provided on the right side surface of the Y guide 42 (the surface plate 10). When the fixing portion 501A and the stator 501C are provided on the right side surface of the Y guide 42 (the surface plate 10) in this way, installation errors of the fixing portion 501A and the stator 501C with respect to the surface plate 10 occur, and the respective thermal expansion coefficients. There is a risk that the fixed portion 501A and the stator 501C are distorted due to the bimetal effect resulting from the difference. In this case, it is difficult to obtain measurement accuracy based on the surface plate 10. For this reason, it is preferable to provide the drive part 80 which has the roller 84 contact | abutted to the right side surface of the Y guide 42 (surface plate 10) like the three-dimensional coordinate measuring apparatus 1 of this embodiment.

  Furthermore, in the three-dimensional coordinate measuring apparatus 500 of Comparative Example 2, the scale 112 is provided on each of the right side surface of the Y guide 42 and the left side surface of the surface plate 10, and the measurement object is disposed on the upper surface 10T of the surface plate 10. The distance from the measurement area to the scale 112 becomes longer. As a result, the difference between the Y coordinate value of the position where the stylus 28 measuring element is actually arranged and the Y coordinate value of the measuring element obtained from the Y coordinate value of the Y carriage 14 actually measured by the scale 112 becomes large. . In addition, the measurement accuracy of the Y coordinate value of the Y carriage 14 is likely to be lowered due to the shake of the Y carriage 14 in the yawing direction. Furthermore, when the scale 112 is installed on the peripheral portion of the surface plate 10, the scale 112 is close to the outside air, so that it is easily affected by the ambient temperature, and an error due to the expansion and contraction of the scale 112 itself is likely to occur.

  Therefore, as in the three-dimensional coordinate measuring apparatus 1 of the present embodiment, the measurement area in which 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 is provided. It is preferable to shorten the distance from the scale 112 to the scale 112. That is, it is preferable that the driven left Y carriage 18, the measurement region, the scale 112, and the driving right Y carriage 16 (drive unit 80) are arranged in this order. As described above, by providing the scale 112 on the driving side (right Y carriage 16 side) and close to the measurement region, 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 dust falls from the upper part (upper side) of the surface plate 10, it does not get on the scale 112, and the And malfunction of reading of the scale 112 due to dust.

  FIG. 20 is a front view (front schematic diagram) showing an appearance of the three-dimensional coordinate measuring apparatus 1 of the present embodiment. 21 is a cross-sectional view (schematic cross-sectional view) taken along line XXI-XXI in FIG. FIG. 22 is a top view showing the top surface 10T of the surface plate 10, and shows the arrangement of the air pads provided on the Y carriage 14 and the drive unit 80. As shown in FIG. Further, a rectangular frame indicated by a two-dot chain line in FIG. 21 indicates the position of the drive unit 80.

  As shown in FIGS. 20 to 22, the three-dimensional coordinate measuring apparatus 1 of the present embodiment has the following differences 1 to 4 with respect to the comparative example 1 and the comparative example 2.

  As a difference 1, in the three-dimensional coordinate measuring apparatus 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 portions of the portion driven by the driving unit 80 so as to sandwich the driving unit 80 are interposed. Air pads are arranged on the left and right and front and rear. As a result, it is possible to reduce pitching errors and rolling errors that lead to worsening of yawing errors.

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

  Further, as shown in FIG. 22, the driven-side air pad 70 is positioned substantially on the opposite side of the surface plate 10 with respect to the drive unit 80, and the line LX connecting the driven-side air pad 70 and the drive unit 80 is driven. What is necessary is just to make it perpendicular | vertical to the line LY which ties 2 pairs of air pads which exist before and after the part 80. From another viewpoint, it is preferable that the driving unit 80 is provided at an intermediate point between the two pairs of air pads on the driving side, and the air pad 70 on the driven side is also provided at an intermediate point between the two pairs of air pads on the driving side.

  As a difference 2, the three-dimensional coordinate measuring apparatus 1 of the present embodiment is provided with a drive unit 80 having a roller 84 that contacts the right side surface of the Y guide 42 (the surface plate 10). Thus, unlike Comparative Example 2, it is possible to prevent the installation error of the drive unit 80 and the distortion due to the bimetal effect from occurring in the drive unit 80, so that the measurement accuracy with respect to the surface plate 10 is improved. can get.

  As a difference 3, in the three-dimensional coordinate measuring apparatus 1 of the present embodiment, the right side Y carriage 16 on the driving side and the left side Y carriage 18 on the driven side that follows (follows and moves) the operation of the right Y carriage 16 are classified. The sliding resistance of the left Y carriage 18 on the driven side is minimized as much as possible (asymmetrical structure). Thereby, 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.

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

  FIG. 23 is a schematic front view of a three-dimensional coordinate measuring apparatus 1A of another embodiment including a 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. The convex portion forms a Y guide 42Z that supports the right Y carriage 16 so as to be movable in the Y-axis direction. The three-dimensional coordinate measuring apparatus 1A has basically the same configuration as the three-dimensional coordinate measuring apparatus 1 of the above embodiment except that the Y guide 42Z is provided.

  In this way, the Y guide 42Z can be formed by the convex portion. Here, when the Y guide 42Z is formed of a material different from the surface plate 10, for example, the heat conductivity of the surface plate 10 and the Y guide 42Z is different, and therefore the Y guide 42Z is deformed. There is. Further, when the surface plate 10 is slightly warped, there is a possibility that measurement based on the surface plate cannot be performed. For this reason, it is preferable to form the Y guide 42 by the groove 40 as described in the above embodiment.

  DESCRIPTION OF SYMBOLS 1 ... Three-dimensional coordinate measuring apparatus, 10 ... Surface plate, 10B, 20B, 42B, 202B ... Lower surface, 10R, 24R, 40R, 42R, 250R ... Right side surface, 10T, 20T, 42T, 202T ... Upper surface, 12 ... Mounting stand, 14 ... Y carriage, 16 ... right Y carriage, 18 ... left Y carriage, 20 ... X guide, 20E, 24E, 202E, 250E ... rear surface, 20F, 24F, 202F, 250F ... front surface, 22 ... Z column, 24 ... Z Carriage, 24L, 40L, 42L, 250L ... left side, 26 ... measurement probe, 28 ... stylus, 40 ... groove, 40B ... bottom surface, 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, 21 , 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 for placing an object to be measured on an upper surface; a gate-shaped Y carriage supported by two columns so as to straddle the surface plate; and support means for supporting the Y carriage movably in the Y-axis direction; A three-dimensional coordinate measuring apparatus comprising a measurement probe extending from the Y carriage to the surface plate side,
Drive means for moving the Y carriage along the Y-axis direction relative to the surface plate on one side of the two columns;
The support means has upper surface side support means disposed opposite to the upper surface of the surface plate on one side of the two support columns and lower surface side support means disposed opposite to the lower surface of the surface plate. And
The three-dimensional coordinate measuring apparatus is arranged such that the driving means is positioned between the upper surface side support means and the lower surface side support means in a direction perpendicular to the upper and lower surfaces of the surface plate.

Images