JP6646454B2 - 3D coordinate measuring device - Google Patents

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 measurement probe in three 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 disposed above a surface plate on which a measurement target is placed. The Y carriage has a column-shaped X guide that extends in the left-right direction (X-axis direction), and the X guide supports the X carriage movably 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 stylus of the measurement probe is supported movably in three X, Y, and Z axes (see Patent Documents 1 to 3 and the like).

  In such a three-dimensional coordinate measuring apparatus, Patent Literature 1 discloses a support structure that supports a Y carriage via air pads (air bearings) between left and right side surfaces of a surface plate and an upper surface of the surface plate.

JP 2007-33052 A JP-A-7-139936 JP-A-7-167641

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

  However, in Patent Literature 1, since the Y carriage is supported by a structure in which the entire width of the surface plate is sandwiched by three air pads of the Y carriage, it is strong against vibration in the left-right direction but weak against vibration in the front-rear direction. There has been a problem that the vibration around the Z axis (the yawing direction) tends to occur.

  Further, in Patent Document 1, since there is no air pad for suppressing the upward movement of the Y carriage, the Y carriage may swing in the direction around the X axis (pitching direction), leading to a decrease in measurement accuracy. There was sex. In addition, when the deflection in the pitching direction occurs on the Y carriage, the deflection in the yawing direction may be deteriorated.

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

  In the three-dimensional measuring apparatus as described above, the measurement of the position (Y coordinate value) of each point on the measurement object in the Y axis direction, that is, the measurement of the Y coordinate value of the stylus of the measurement probe is performed by using the Y carriage. This is performed by measuring the position (Y coordinate value) in the axial direction. A linear encoder is used as position detection means for measuring the Y-axis coordinate value of the Y carriage. A scale (a member on which a scale is formed) in the linear encoder is often provided on a portion of a surface plate near a driving unit provided on a Y carriage, as described in Patent Document 2. Further, as described in Patent Literature 3, when a Y guide that supports the Y carriage so as to be movable in the Y axis direction and a Y guide that is a member separate from the surface plate is provided, the Y guide is attached to the Y guide. Some are equipped with scales.

  However, when the scale is installed on the Y guide, which is a member separate from the surface plate, it is necessary to consider the difference in thermal deformation between the surface plate and the Y guide and the stability of the fastening portion between the surface plate and the Y guide. It is difficult to maintain high measurement accuracy.

  In addition, even when the scale is installed on the surface plate, conventionally, since the scale is installed on the periphery of the surface plate such as a side surface along the Y-axis direction of the surface plate, the scale and the object to be measured are arranged. The distance from the scale to the measurement area becomes longer due to the interposition of a column standing upright along the Z-axis direction of the Y carriage between the measurement areas.

  On the other hand, the Y-carriage (the X guide that extends over the left and right) is arranged along the X-axis direction, but the direction of the X-guide is shifted from the X-axis direction due to the yaw direction of the Y carriage (direction around the Z-axis). As the distance from the measurement area to the scale is longer, the measurement obtained from the Y coordinate value of the position where the tracing stylus of the measurement probe is actually arranged in the measurement area and the Y coordinate value of the Y carriage actually measured by the scale The difference from the Y coordinate value of the child increases.

  Therefore, if the distance from the measurement area to the scale is long as in the prior art, the measurement accuracy of the Y coordinate value of the Y carriage, that is, the measurement accuracy of the Y coordinate value of the object to be measured, due to the deflection of the Y carriage in the yawing direction, etc. It is easy to cause decrease.

  Further, when a scale is installed on the periphery of the surface plate, the scale is close to the outside air, so that the scale is easily affected by the ambient temperature, and errors due to expansion and contraction of the scale itself are likely to occur.

  The present invention has been made in view of such circumstances, and a three-dimensional coordinate measuring apparatus that improves the measurement accuracy of the position of the Y carriage in the Y-axis direction, that is, the measurement accuracy of the Y coordinate value of the measurement object. The second purpose is to provide.

  Further, in the three-dimensional coordinate measuring apparatus as described above, Patent Document 1 discloses a support for supporting a Y carriage via an air pad (air bearing) between left and right side surfaces of a surface plate and an upper surface of the surface plate along the left and right side surfaces. The structure is disclosed.

  Further, as described in Patent Document 1, in order to avoid a decrease in measurement accuracy due to a decrease in straightness or vibration of the surface of the surface plate due to deformation of the surface plate, a granite having high hardness and large specific gravity is used as the surface plate. Stone and marble are used.

  On the other hand, a stone surface plate has a low thermal conductivity, making it difficult for heat to be transmitted to the inside. When the temperature of the outside air around the surface plate (ambient temperature) changes, the inside of the surface plate becomes a uniform temperature. Until a temperature gradient occurs over a long period of time. When such a temperature gradient occurs, there is a problem in that the surface plate is deformed, and the straightness of the surface of the surface plate (upper surface, side surface, etc.) is reduced, thereby lowering measurement accuracy. In particular, since the left and right side surfaces of the surface plate are used as guides for the Y carriage, a decrease in straightness of the left and right side surfaces causes an error in the support angle of the Y carriage, and greatly affects the measurement result.

  Therefore, Patent Document 1 discloses that a surface of a surface plate not used as a guide of the Y carriage, that is, front and rear side surfaces is covered with a heat insulating member. According to this, since the amount of heat entering and exiting from the front and rear side surfaces of the surface plate is reduced, even if the ambient temperature changes and a temperature gradient is generated inside the surface plate, the generation of the temperature gradient in the Y-axis direction is suppressed. . Therefore, regardless of a change in the ambient temperature, a decrease in straightness on the left and right side surfaces of the surface plate is suppressed, and a decrease in measurement accuracy is suppressed.

  By the way, as in Patent Literature 1, a measurement area in which an object to be measured is placed and measurement is performed, and a guide area for guiding the Y carriage in the Y-axis direction are integrally formed. In this case, heat generated by a motor of a Y drive mechanism for moving the Y carriage in the Y-axis direction flows into the measurement area via the guide area.

  Since the measurement region has a large volume and a large heat capacity (low heat conductivity), it takes a long time for the surface plate to reach a uniform temperature when heat flows into the measurement region.

  Therefore, even if the front and rear side surfaces of the surface plate are covered with a heat insulating member as in Patent Literature 1, the occurrence of a temperature gradient in the Y-axis direction of the surface plate due to the influence of the surrounding air temperature is suppressed, but the temperature is generated by the Y drive mechanism. Heat may cause a temperature gradient in the Y-axis direction. In this case, the straightness of the surface of the guide portion is reduced, and the measurement accuracy is reduced.

  It is a third object of the present invention to provide a three-dimensional coordinate measuring apparatus capable of performing highly accurate measurement while suppressing deformation of a surface plate due to heat. I do.

  A three-dimensional coordinate measuring apparatus for achieving the object of the present invention has an upper surface, a lower surface, and side surfaces, a surface plate on which an object to be measured is placed, and a measurement probe. A Y-carriage of a gate type movable in the axial direction, the Y-carriage supported on a surface plate by two support members, wherein the two support members drive the Y carriage in the Y-axis direction. A first support member having a first support member and a second support member that moves following the first support member, and the surface plate has a pair of pairs perpendicular to the upper and lower surfaces of the surface plate on the first support member side. The first support member has two side surfaces, and the first support member is supported by the base plate at least one of an upper and lower support member that sandwiches the vertical direction of the base plate and a side support member that sandwiches the two side surfaces of the pair, and the second support member Is supported by an upper surface support member on the upper surface of the surface plate.

  According to the three-dimensional coordinate measuring device, when the Y carriage is moved along the Y direction, the swing around the Z axis is suppressed, and the yawing error can be suppressed. Further, it is possible to reduce a pitching error and a rolling error that lead to a worsening of the yawing error. As a result, the deflection of the Y carriage can be suppressed.

  In the three-dimensional coordinate measuring apparatus according to another aspect of the present invention, when the side surface of the surface plate on the side of the first support member is the first side surface, the first side surface on the upper surface of the surface plate is in the Y-axis direction. And the first support member is slidably disposed on the first side surface and the inner surface of the groove, and the inner surface of the groove has a second surface along the Y-axis direction opposed to each other. And a third side, and the second side is formed closer to the first side than the third side, and the two sides are a first side and a second side. It is composed of By forming the two side surfaces by the grooves formed in the surface plate, measurement accuracy based on the surface plate can be obtained.

  In the three-dimensional coordinate measuring apparatus according to another aspect of the present invention, when the first support member is supported on the surface plate by at least the side support member, the side support member is slidably disposed on one of the two side surfaces. A first support member and a second support member provided at two locations along the Y-axis direction, and slidably disposed on the other of the two side surfaces, A third support member and a fourth support member provided at the location, wherein the first support member and the third support member, and the second support member and the fourth support member They are arranged at opposing positions. As a result, the swing (yawing error) of the Y carriage around the Z axis is particularly suppressed.

  In the three-dimensional coordinate measuring device according to another aspect of the present invention, when the first support member is supported on the surface plate by at least the upper and lower support members, the upper and lower support members are slidably disposed on the upper surface of the surface plate. And a fifth support member and a sixth support member provided at two locations along the Y-axis direction, and slidably disposed on the lower surface of the surface plate. A seventh support member and an eighth support member provided at the location, wherein the fifth support member and the seventh support member, and the sixth support member and the eighth support member They are arranged at opposing positions. Thereby, the swing (pitching error) around the X axis of the Y carriage is particularly suppressed.

  In the three-dimensional coordinate measuring device according to another aspect of the present invention, when the first support member is supported on the surface plate by the side support member, the drive mechanism is provided at a position between the two side support members. When the first support member is in contact with one of the two side surfaces and the first support member is supported on the surface plate by the upper and lower support members, it contacts one of the two side surfaces at a position between the two upper and lower support members. Thus, the vibration applied to the Y carriage can be absorbed by the side support members and the upper and lower support members provided at two locations along the Y axis direction. Thereby, it is possible to reduce the yawing error, and the pitching error and the rolling error that lead to the deterioration of the yawing error.

  In the three-dimensional coordinate measuring device according to another aspect of the present invention, the distance in the Y-axis direction at two locations is larger than the distance between the two side surfaces. Thereby, the vibration applied to the Y carriage can be reduced.

  In the three-dimensional coordinate measuring device according to another aspect of the present invention, the driving mechanism includes a roller that contacts one of the two side surfaces and a motor that rotates the roller.

  In the three-dimensional coordinate measuring apparatus according to another aspect of the present invention, the scale disposed on the surface plate along the Y-axis direction at a position between the first support member and the second support member allows the Y carriage to move. A position detecting unit for detecting a position in the Y-axis direction is provided. Thereby, the distance from the measurement area where the measurement target is arranged on the upper surface of the surface plate to the scale can be shortened, so that the measurement accuracy can be improved.

  Further, even if there is a yawing error caused by the movement of the Y carriage in the Y-axis direction, since the scale exists between the measurement region and the first support member, the scale is closer to the measurement region (that is, closer to the work). Scale) can be read. That is, the scale can be read at a position where the yawing error is smaller than that on the drive side (first support member, drive mechanism), so that the measurement accuracy can be further improved.

  In the three-dimensional coordinate measuring apparatus according to another aspect of the present invention, when the side surface on the side of the first support member of the surface plate is the first side surface, the side of the first side surface on the upper surface of the surface plate is A groove is formed along the Y-axis direction, and the first support member is slidably disposed on the first side surface and the inner surface of the groove, and the inner surface of the groove extends along the Y-axis direction facing each other. A second side surface and a third side surface, and the second side surface is formed closer to the first side surface than the third side surface, and the scale is installed on the third side surface. You. Thereby, the distance from the measurement area where the measurement target is arranged on the upper surface of the surface plate to the scale can be shortened. Further, since the scale is installed inside the groove inside the surface plate, the influence of the temperature change of the outside air is small, and the decrease in accuracy due to expansion and contraction of the scale is suppressed. As a result, measurement accuracy can be improved.

  In addition, the scale is mounted on a third side of the platen, a vertical plane perpendicular to the top surface of the platen. For this reason, even if dust or dust falls from the upper part (upper part) of the surface plate, the dust does not ride on the scale and malfunction of scale reading due to dust or dust does not occur.

  A three-dimensional coordinate measuring device according to another aspect of the present invention includes a covering member that covers the opening of the groove. Thereby, since the inside of the groove can be shielded from the outside air, the outside air can be prevented from directly hitting the scale, and the temperature change inside the groove can be suppressed. Therefore, the expansion and contraction of the scale due to the temperature change of the outside air is more reliably suppressed.

  A three-dimensional coordinate measuring apparatus according to another aspect of the present invention includes a heat insulating member that covers a side surface of the surface plate along the X-axis direction. As a result, heat that enters and exits from the side surface of the surface plate to the inside or outside of the surface plate is reduced by the heat insulating member, so that even if the ambient temperature of the surface plate changes, the temperature change hardly occurs inside the surface plate. Thus, deformation of the surface plate is suppressed. Further, even if a temperature change occurs inside the surface plate, the occurrence of a temperature gradient in the Y-axis direction is suppressed, so that a decrease in the straightness of at least the first side surface is suppressed, and the Y-carriage in the Y-axis direction is suppressed. The movement is performed with high accuracy.

  In the three-dimensional coordinate measuring device according to another aspect of the present invention, the upper and lower support members, the side support members, and the upper support members are air pads.

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

  According to the three-dimensional coordinate measuring apparatus of the present invention, it is possible to improve the measurement accuracy by suppressing the deflection of the Y carriage.

  Further, according to the three-dimensional coordinate measuring device of the present invention, it is possible to improve the measurement accuracy of the position of the Y carriage in the Y-axis direction, that is, the measurement accuracy of the Y coordinate value of the measurement object.

  ADVANTAGE OF THE INVENTION According to the three-dimensional coordinate measuring apparatus of this invention, deformation | transformation of the surface plate by heat can be suppressed and highly accurate measurement can be performed.

Perspective view showing the appearance of a three-dimensional coordinate measuring apparatus to which the present invention is applied (first embodiment) Front view showing the appearance of a 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 A perspective view showing the Y carriage with the cover removed. FIG. 2 is a top view showing the upper surface of the surface plate, showing an arrangement of an air pad provided on a Y carriage with respect to the surface plate (first embodiment). FIG. 2 is a right side view showing a right side surface of the surface plate, showing an arrangement of an air pad provided on a Y carriage with respect to the surface plate (first embodiment). Front view showing the groove of the surface plate enlarged A perspective view showing the Z column removed from the X guide. A perspective view showing the Z column removed from the X guide. A perspective view showing the Z column removed from the X guide. A perspective view showing a support portion of the Z column removed from the X guide. A perspective view showing a support portion of the Z column removed from the X guide. Schematic diagram showing the positional relationship between the support points at which the Y guide of the surface plate supports the Y carriage from the upper surface side of the surface plate Schematic view showing the positional relationship between the support points at which the Y guide of the surface plate supports the Y carriage from the right side of the surface plate (first embodiment) FIG. 7 is an enlarged perspective view showing a groove portion of a surface plate, showing a bellows cover (second embodiment). Schematic diagram showing the positional relationship between the support point where the Y guide of the surface plate supports the Y carriage, the scale in the linear encoder, and the measurement area where the object to be measured is arranged, from the upper surface side of the surface plate (second embodiment) Form) Perspective view showing the appearance of a three-dimensional coordinate measuring apparatus to which the present invention is applied (third embodiment) FIG. 11 is a top view showing the upper surface of the surface plate, showing an arrangement of an air pad provided on a Y carriage with respect to the surface plate (third embodiment). FIG. 9 is a right side view showing the right side of the surface plate, and shows an arrangement of an air pad provided on a Y carriage with respect to the surface plate (third embodiment). Diagram showing shrinkage of platen when ambient temperature decreases Diagram showing shrinkage of platen when ambient temperature rises Front view (schematic front view) showing the appearance of the three-dimensional coordinate measuring device of Comparative Example 1. Sectional view (cross-sectional schematic view) along line XXIV-XXIV in FIG. Front view (schematic front view) showing the appearance of the three-dimensional coordinate measuring device of Comparative Example 2. Front view (schematic front view) showing the appearance of the three-dimensional coordinate measuring device of Comparative Example 3. Front view (schematic front view) showing the appearance of the three-dimensional coordinate measuring apparatus 1 of the present embodiment. Sectional view (cross-sectional schematic view) along the line XXVIII-XXVIII in FIG. FIG. 4 is a top view showing the top surface of the surface plate, showing an arrangement of each air pad provided on the Y carriage and a driving unit. Front view showing the appearance of the three-dimensional coordinate measuring apparatus of another embodiment (schematic front 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 (first embodiment) showing the 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 figures has a surface plate 10 supported on a mounting surface (floor surface) via a gantry 12. The surface plate 10 is integrally formed in a rectangular shape from a stone material such as granite (granite, granite) or marble (marble, limestone, crystalline limestone), 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. In addition, the surface plate 10 is not limited to a stone surface plate.

  On the upper surface 10T side of the surface plate 10, a gate-shaped Y carriage 14 is installed across the surface plate 10. The Y carriage 14 is a first support member that extends along the Z-axis direction on each of the right side and the left side (one side) of the base 10 when the base 10 is viewed from the front side. A right Y-carriage 16 and a left Y-carriage 18 as a second support member, and a column-shaped 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. Having.

  The lower end of the right Y carriage 16 is movably supported by a later-described Y guide 42 formed on the surface plate 10 along the Y-axis direction. 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 driving 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.

  Thus, 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 driving unit at the lower end of the right Y carriage 16 makes the right Y carriage 16 a driving side, and the left Y carriage It moves in the Y-axis direction with 18 as the driven side.

  On the X guide 20, a Z column 22 is movably supported 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.

  A columnar Z-carriage 24 extending along the Z-axis is movably supported in the Z-axis direction inside the Z-column 22 (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 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 measurement probe 26 has, for example, a rod-shaped stylus 28 having a tip sphere. The measurement probe 26 determines whether or not the tip (tip sphere) of the stylus 28 is in contact with the measurement target and the measurement target at the tip of the stylus 28. The displacement of the stylus 28 caused by the contact with the stylus 28 is detected.

  The three-dimensional coordinate measuring apparatus 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 ball) of the stylus 28 is moved along the surface of the measurement object placed on the upper surface 10T of the surface plate 10. Then, 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 at that time. By measuring the position (displacement amount), the three-dimensional coordinates of each position on the surface of the measurement object are measured. It should be noted that the processing relating to the measurement of the three-dimensional coordinates is well known, and therefore detailed description is omitted.

  Next, a Y drive mechanism that supports the Y carriage 14 movably 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, two support members) 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, respectively, 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 (corresponding to a first side surface of the present invention). A groove 40 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 along the Y-axis direction.

  In FIGS. 1 and 2, a telescopic covering member such as a bellows cover is installed at 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 platen 10. FIG. 3 and FIG. 4 show a state in which the covering members are removed.

  The groove 40 includes a right side surface 40R (corresponding to a second side surface of the present invention) and a left side surface 40L (corresponding to a third side surface of the present invention) perpendicular to the X axis and a bottom surface 40B perpendicular to the Z axis. And

  Thereby, 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.

  Note that 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 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 perpendicular to the Z axis.

  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 therebetween is the Y guide 42. The upper surface 42T of the base plate 10 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 is a perspective view of the Y carriage 14 in a state where the covers of the respective parts are removed. As shown in FIGS. 4 and 5, the lower end of the right Y carriage 16 has a Y-axis direction. Is provided with a wide supporting portion 50.

  The support portion 50 is formed in a forked shape as viewed from the front side as shown in FIG.

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

  As shown mainly in FIG. 3, the support portion 50 faces the upper surface 42T of the Y guide 42 and is disposed along a direction (horizontal direction) orthogonal to the Z axis (horizontal direction). And 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 from the base end portion 52 in the Z-axis direction. And a left side portion 56 disposed on the opposite side.

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

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

  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, respectively, and show the arrangement of the air pads provided on the Y carriage 14 with respect to the surface plate 10.

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

  The two air pads 64F and 64E (corresponding to the side support members of the present invention) arranged along the right side surface 42R of the Y guide 42 are provided at two places along the Y axis direction (Y axis direction) on the right side portion 54 of the support portion 50. (Two points on a straight line parallel to the Y guide 42), and is disposed facing left side 42R of the Y guide 42 and facing left.

  Two air pads 66F and 66E (corresponding to side support members of the present invention) arranged along the left side surface 42L of the Y guide 42 (the right side surface 40R of the groove 40) are arranged in the Y-axis direction on the left side portion 56 of the support portion 50. Are provided at two positions (two positions on a straight line parallel to the Y axis) along the right side, and are arranged rightward facing the left side surface 42L of the Y guide 42. The air pads 64F, 64E, 66F, and 66E correspond to the first support member, the second support member, the third support member, and the fourth support member of the present invention.

  Two air pads 68F and 68E (see FIGS. 3 and 7 and corresponding to the upper and lower support members of the present invention) arranged along the lower surface 42B of the Y guide 42 extend along the Y-axis direction at the distal end portion 58 of the support portion 50. At two locations (two locations on a straight line parallel to the Y axis), and is arranged upward facing the lower surface of the Y guide 42. The air pads 62F, 62E, 68F, 68E correspond to the fifth support member, the sixth support member, the seventh support member, and the eighth support member of the present invention.

  An air pad 70 (corresponding to an upper surface support member of the present invention) disposed on the upper surface near the left side surface of the surface plate 10 is provided at a lower end portion of the left Y carriage 18 and faces downward on the upper surface 10T of the surface plate 10. Placed in

  Here, in each of the base end portion 52, the right side portion 54, the left side portion 56, and the front end portion 58 of the support portion 50, the air pads 62F, 64F, 66F, 68F installed on the front side (front side) are in the Y-axis direction. , The air pads 62E, 64E, 66E, and 68E arranged on the rear side (back side) are substantially at the same position in the Y-axis direction. Placed in

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

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

  The position of the air pad 70 provided at the lower end of the left Y carriage 18 is such that the position in the Y axis direction is the Y axis of the center of gravity of all the members (the Y carriage 14 and the 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 position in the direction.

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

  For reference, the surface plate 10 has a width (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 is about 600 mm to about 800 mm, and the support 50 has a width (depth) in the Y-axis direction of about 650 mm.

  According to the support means for 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 (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 by the surface plate 10 (upper surface 10T) via the air pad 70 of the left Y carriage 18.

  In addition, 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 are formed. 66E, 68F and 68E are slidable with respect to the Y guide 42 in the Y-axis direction, and the air pad 70 of the left Y carriage 18 is slidable with respect to the upper surface 10T of the surface plate 10.

  Therefore, the Y carriage 14 can move in the Y-axis direction with respect to the surface plate 10.

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

  As shown in FIG. 4, a driving unit 80 is provided on the right side 54 of the support unit 50. As shown in FIGS. 6 and 7, the drive unit 80 is disposed 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. Note that the drive unit 80 may be disposed on the left side portion 56 of the support unit 50 and at a position substantially intermediate between the two air pads 66F and 66E.

  The drive unit 80 is configured integrally with a motor 82, a rotatable roller 84, and a reduction mechanism that connects the two so that power can be transmitted to a support member. When the motor 82 is driven, the roller 84 is driven. Rotate.

  As shown in FIG. 6, the drive unit 80 moves the 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. The right side surface 42R (the right side surface 10R of the surface plate 10) is installed on the right side portion 54 of the support portion 50.

  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.

  In addition, as a driving unit of the Y carriage 14, in addition to the driving unit 80, a driving unit that contacts the left side surface 42 </ b> L of the Y guide 42 may be provided to face the driving unit 80, for example. Only the drive unit that contacts the left side surface 42L of the guide 42 may be provided.

  Next, the position detecting means of the Y carriage 14 in the Y driving mechanism will be described.

  FIG. 8 is an enlarged front view showing 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 and a scale 112 provided with a grid scale is installed along the Y-axis direction. (See FIG. 6).

  On the other hand, an optical sensor 114 constituting the linear encoder 110 is provided with a support member on the left side portion 56 of the support section 50, and is disposed at a position facing the scale 112 (see FIG. 6). Then, the optical sensor 114 outputs a detection signal corresponding to the grid graduation of the scale 112 formed at a position facing 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 supports the Z column 22 movably in the X-axis direction and moves the Z column 22 in the X-axis direction will be described.

  First, support means (X guide mechanism) for 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 is a support section 200 on which various components are assembled, and includes a support section 200 corresponding to an X carriage. The support section 200 has a rectangular column-shaped 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, air is blown out 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 by blowing air. A disc-shaped air pad slidable with respect to 20 is provided.

  On the front surface 202F of the X guide insertion hole 202, as shown in FIG. 10, four air pads 210, 210, 210, 210 are arranged, one at each of four locations that are vertically and horizontally symmetrical. 20 and 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 two upper positions and one lower position. Is arranged facing forward facing the rear surface 20E (see FIG. 5).

  On the upper surface 202T of the X guide insertion hole 202, as shown in FIG. 9, two air pads 214, 214, one for each of two places on the left and right, are arranged, and the upper surface 20T of the X guide 20 (see FIG. 5). Are arranged facing downward.

  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 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 section 200, the support section 200 is moved through the air pads 210, 212, 214, and 216. The Z column 22 is supported by the X guide 20 via the support portion 200 while being supported by the X guide 20.

  In addition, by ejecting air from each of the air pads 210, 212, 214, and 216, each of 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 becomes movable in the X-axis direction.

  Next, 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 202 </ b> E of the X guide insertion hole 202 has the same configuration as the drive unit 80 in the above-described Y drive mechanism, and includes a motor 222 and rollers 224 (see FIG. 11). A drive unit 220 is provided. The driving 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 located above the rear surface 202E of the X guide insertion hole 202. The X guide 20 is installed so as to come into contact with the rear surface 20E (see FIG. 5) at a position substantially intermediate between the two air pads 212, 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 unit 200 are provided with an optical linear encoder similar to the above-described linear encoder 110 of the Y drive mechanism as a position detection unit of the Z column 22 in the X drive mechanism. In the figure, a long plate-shaped scale is installed along the X-axis direction, and the optical sensor is arranged on the support section 200 at a position facing the scale.

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

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

  FIGS. 12 and 13 show a state where 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 drawings, the support portion 200 is removed. A rectangular Z-carriage insertion hole 250 extending in the Z-axis direction through which the quadrangular prism-shaped Z carriage 24 is inserted is provided in front of the X-guide insertion hole 202.

  In the support portion 200, air is applied to 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 which is slidable with respect to the Z carriage 24 is provided.

  In the vicinity of 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 surface 250F, the rear surface 250E, the right side surface 250R, and the left side surface 250L of the Z carriage insertion hole 250 260, 262, 264, and 266 are arranged, and each of the air pads 260, 262, 264, and 266 is a front surface 24F, a rear surface 24E, a right side surface 24R, and a left side surface 24L (see FIG. 11) of the Z carriage 24. , Facing backward, forward, left, and right.

  As shown in FIG. 13, near the upper opening of the Z carriage insertion hole 250, a total of three air pads 260, 262, 264 are provided, 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. Are arranged, and each of the air pads 260, 262, 264 is arranged to face the front surface 24F, the rear surface 24E, and the right side surface 24R of the Z carriage 24, facing rearward, frontward, and leftward.

  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 the air pads 266 and 266 face the left side surface 24L of the Z carriage 24. Then placed 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 section 200, the support section 200 is moved through the air pads 260, 262, 264, 266. The Z carriage 24 is supported.

  In addition, 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 unit 200 becomes slidable with respect to the Z carriage 24. It is possible to move in the Z-axis direction.

  Next, 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 above-described Y drive mechanism, and includes a motor 272 and rollers 274 (see FIG. 13). A driving unit 270 is provided. The driving 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. The air pad 260 is installed so as to abut on the front surface 24F of the Z carriage 24 at a position substantially in the middle between the two air pads 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 unit 200 are provided with an optical linear encoder similar to the above-described linear encoder 110 of the Y drive mechanism as a position detection unit of the Z carriage 24 in the Z drive mechanism. In the figure, a long plate-shaped scale is installed along the Z-axis direction, and the optical sensor is disposed on the support section 200 at a position facing the scale.

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

  In the three-dimensional coordinate measuring apparatus 1 configured as described above, the effect of mainly suppressing the shake of the Y carriage 14 around the Z axis (yawing direction) and around the X axis (pitching direction) 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.

  In the figure, two front and rear support points P1 and P2 present 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 present 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 exist on the right side surface 42R of the Y guide 42. The supporting point P0 indicates a position where the roller 84 of the driving section 80 of the Y carriage 14 (supporting section 50) comes into contact (see FIG. 6).

  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 serving as the fixed support points P1 and P2 cannot move in the support portion 50 of the Y carriage 14 in the normal direction of the left side surface 42L of the Y guide 42, which is the guide surface on which they slide. Supported by On the other hand, the air pads 64F and 64E serving as the auxiliary support points P3 and P4 are provided on 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 as to be able to move forward and backward, and is urged in a direction to contact the right side surface 42R.

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

  Therefore, the angular position of the Y carriage 14 in the direction around the Z axis (the yawing direction) is uniquely determined by the positions of the support points P1 and P2, and the swing in the yawing direction is suppressed. Then, the deflection of the X guide 20 (X axis) in the yawing direction is suppressed, so that the measurement is performed on the measurement target placed 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 are obtained with high accuracy based on the position of the Y guide 42 (left side surface 42L).

  FIG. 15 is a schematic diagram showing the positional relationship between the support points at which the Y guides 42 of the surface plate 10 support the Y carriage 14 from the right side 10R side of the surface plate 10.

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

  According to this, the Y guide 42 supports the Y carriage 14 by the two front and rear support points P7 and P8 of the lower surface 42B as well as the two front and rear support points P5 and P6 of the upper surface 42T.

  Therefore, the deflection 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. However, the deflection of the Y carriage 14 in the pitching direction is suppressed.

  In particular, since the driving unit 80 is disposed between the supporting points P5 and P6 and the supporting points P7 and P8 in the Z-axis direction (see FIG. 7 and the like), the driving force of the driving unit 80 causes the Y carriage 14 to move in the pitching direction. Since the rotational force is hardly generated, the swing of the Y carriage 14 in the pitching direction is suppressed.

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

  The deflection of the Z carriage 24 (Z axis) in the pitching direction is suppressed, so that the Y coordinate value and the Z coordinate value of the measurement target in the measurement area measured by the measurement probe 26 can be adjusted by the Y guide 42 (upper surface 42T). ) Can be obtained with high accuracy based on the position.

  In addition, by forming the groove 40 in the surface plate 10 to make a part of the area along the right side surface 10R of the surface plate 10 a Y guide 42, compared with a case where the Y guide 42 is formed by a separate member, Thermal deformation of the Y guide 42 is less likely to occur, and the straightness of the Y guide 42 is easily maintained continuously. In addition, since the left and right sides 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 continuously maintained.

  Therefore, the fluctuation 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. Measurement accuracy can be maintained. Further, the Y guide 42 (Y guide mechanism) can have a simple and inexpensive configuration as compared with the case where the Y guide 42 is configured by a separate member.

  Therefore, by using a part of the surface plate 10 as the Y guide 42, the shape change of the Y guide 42 during the measurement is small compared to the case where the Y guide 42 is formed of a separate member from the surface plate 10, and the Y guide 42 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 need not necessarily be a stone surface plate.

  Next, in the three-dimensional coordinate measuring apparatus 1 according to the second embodiment of the present invention, mainly the measurement accuracy of the position (Y coordinate value) of the Y carriage 14 in the Y axis direction, that is, the Y coordinate of the measurement target A configuration for improving the measurement accuracy of the value will be described. In the description of the second embodiment, the same components as those of the first embodiment are denoted by the same reference numerals, and description thereof will be omitted.

  First, the covering member that covers the upper opening of the groove 40 will be described.

  FIG. 16 is an enlarged perspective view showing the groove 40 of the surface plate 10.

  As shown in the figure, a right rail 130R and a left rail 130L are fixedly arranged on the surface plate 10 at the right edge and the left edge of the upper opening of the groove 40.

  Both the right rail 130R and the left rail 130L extend from the front end (front end) to the rear end (rear end) of the groove 40, and the right rail 130R is connected to the right side 40R of the groove 40 (Y guide 42). The left rail 130L is provided along the left side surface 40L of the groove 40 (see FIG. 6).

  The right rail 130R and the left rail 130L have a left-right symmetrical shape, and are provided with guide grooves 132R and 132L, each having a lateral opening and an opening in a direction facing each other.

  At the upper opening of the groove 40, an extendable bellows cover 134 is provided in which the left and right edges are fitted and supported in the guide groove 132R of the right rail 130R and the guide groove 132L of the left rail 130L.

  The bellows cover 134 is installed separately on the front bellows cover 134F and the rear bellows cover 134E (see FIG. 1) with the left side portion 56 of the support portion 50 in the right Y carriage 16 therebetween. The bellows cover 134 </ b> F has a front end fixed to a front side surface of the platen 10 via a fixing member (not shown) (such as a covering member that covers the front side surface of the platen 10), and a rear end portion of the left side of the support portion 50. 56 is fixed to the front surface. The bellows cover 134E installed on the rear side has a front end fixed to the rear surface of the left side portion 56 of the support portion 50, and a rear end formed on a rear side surface of the platen 10 with a fixing member (not shown) covering the rear side surface of the platen 10. Fixed to the surface plate 10 via a covering member or the like that performs the coating.

  According to this, the upper opening of the groove 40 is covered with the bellows cover 134. Then, the bellows cover 134 expands and contracts in the Y-axis direction along with the movement of the Y carriage 14 (support portion 50) in the Y-axis direction, and when the Y carriage 14 moves forward, the bellows cover 134F on the front side contracts, The rear bellows cover 134E extends. When the Y carriage 14 moves rearward, the bellows cover 134F on the front side expands, and the bellows cover 134E on the rear side contracts. Therefore, the upper opening of the groove 40 is always covered with the bellows cover 134 regardless of the position of the Y carriage 14 in the Y-axis direction.

  This prevents the outside air from directly hitting the scale 112 installed inside the groove 40, and also suppresses the temperature change inside the groove 40, and the scale 112 expands and contracts due to the temperature change of the outside air. Is prevented.

  Further, it is possible to prevent dust and dirt from entering the inside of the groove 40, and to cause dust and the like to adhere to the scale 112 and cause a measurement error due to a reading error of the grid scale. This prevents a situation where dust or the like adheres to the air pads 66F and 66E and the movement of the Y carriage 14 in the Y-axis direction becomes unstable.

  Next, in the three-dimensional coordinate measuring apparatus 1 configured as described above, mainly the measurement accuracy of the position (Y coordinate value) of the Y carriage 14 in the Y-axis direction, that is, the measurement accuracy of the Y coordinate value of the measurement target. The effect of the improvement will be described.

  FIG. 17 shows the positional relationship between the support point where the Y guide 42 of the surface plate 10 supports the Y carriage 14, the scale 112 in the linear encoder 110, and the measurement area where the object to be measured is arranged. It is the schematic diagram shown from the side.

  In the figure, two front and rear support points P1 and P2 present 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 present 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 exist on the right side surface 42R of the Y guide 42. The supporting point P0 (drive point) indicates a position where the roller 84 of the drive unit 80 of the Y carriage 14 (support unit 50) comes into contact (see FIG. 6).

  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 serving as the fixed support points P1 and P2 cannot move in the support portion 50 of the Y carriage 14 in the normal direction of the left side surface 42L of the Y guide 42, which is the guide surface on which they slide. Supported by On the other hand, the air pads 64F and 64E serving as the auxiliary support points P3 and P4 are provided on 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 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 scale 112 installed on the left side surface 40L of the groove 40 is arranged between the measurement area and the Y guide 42 provided with the support points P0 to P4. That is, the scale 112 is arranged on the measurement area side of the air pads 64F, 64E, 66F, 66E of the Y carriage 14 (the right Y carriage 16) and the driving unit 80.

  Therefore, the right Y carriage 16 which is a support member along the Z-axis direction of the Y carriage 14 does not intervene between the measurement region and the scale 112, and the distance from the measurement region to the scale 112 is short.

  Therefore, even if the direction of the X guide 20 of the Y carriage 14 is deviated from the X axis direction due to the yaw direction of the Y carriage 14 (direction around the Z axis), the stylus 28 of the measurement probe 26 in the measurement area is not moved. The difference between the Y coordinate value of the actually arranged position and the Y coordinate value of the stylus 28 obtained from the Y coordinate value of the Y carriage 14 measured by the scale 112 (linear encoder 110) becomes smaller.

  Therefore, even when the Y carriage 14 fluctuates in the yawing direction, the measurement accuracy of the Y coordinate value of the Y carriage 14, that is, the measurement accuracy of the Y coordinate value of the measurement object is improved.

  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 uses one of the support points P3 and P4 as auxiliary support points and one support point P0 of the right side surface 42R. , And is stabilized at the two support points P1 and P2 on the left side surface 42L. Thus, the configuration is such that the Y carriage 14 does not easily swing in the yawing direction.

  In addition, since the scale 112 is installed on the surface plate 10, the influence of thermal deformation of the Y guide and the influence of the Y-guide on the surface plate are lower than when the scale 112 is installed on a Y guide or the like separate from the surface plate 10. Measurement accuracy does not decrease due to instability of the fastening portion with the guide. Therefore, high measurement accuracy can be maintained continuously.

  Further, since the scale 112 is not provided on the peripheral portion (the right side surface 10R, the left side surface 10L, etc.) of the surface plate 10 but is disposed inside the surface plate 10, the influence of the temperature change of the outside air is small, and the scale 112 A decrease in accuracy due to expansion and contraction of the slab is suppressed. In particular, since the bellows cover 134 is installed at the upper opening of the groove 40 to shield the inside of the groove 40 from the outside air as described above, it is possible to prevent the outside air from directly hitting the scale 112. Internal temperature changes are also suppressed. Therefore, the expansion and contraction of the scale 112 due to the temperature change of the outside air is surely suppressed, and it is not necessary to use an expensive material that does not expand and contract even if a temperature change occurs, and it is possible to use an inexpensive scale.

  Further, in the above-described embodiment, the scale 112 is provided on the left side surface 40L of the groove 40, but the inner surface of the groove 40 other than the left side surface 40L (the right side surface 40R of the groove 40, the bottom surface 40B, etc.) along the Y-axis direction. By installing the same, the same effect as described above can be obtained.

  Further, in the above embodiment, the bellows cover 134 is used as the covering member for covering the upper opening of the groove 40, but a type of covering member other than the bellows cover may be used. For example, a covering member made of an elastic material may cover the upper openings of the grooves 40 on the front side and the rear side of the lower end portion (the left side portion 56 of the support portion 50) of the Y carriage 14 that fits into the groove 40. . In addition, the entire upper opening of the groove 40 is covered with an integrally formed covering member, and the lower end portion of the Y carriage 14 (the left side portion 56 of the support portion 50) is inserted into the covering member from the outside to the inside of the groove 40. The insertion passage may be formed along the groove 40 (Y-axis direction) such that the insertion passage is closed when the lower end of the Y carriage 14 is not inserted. Further, a configuration in which a covering member for covering the upper opening of the groove 40 is not provided may be adopted.

  In the above embodiment, an optical linear encoder and a position detecting means of the Y carriage 14 for measuring the Y coordinate value of the Y carriage 14, a position detecting means of the Z column 22, and a Z carriage 24 are used. Although a form using a scale has been described, other types of linear encoders and scales, such as a magnetic type, may be used instead of the optical type.

  Next, in the three-dimensional coordinate measuring apparatus 1 according to the third embodiment of the present invention, a configuration for mainly suppressing deformation of the surface plate due to heat will be described. In the description of the third embodiment, the same components as those in the first or second embodiment are denoted by the same reference numerals, and description thereof will be omitted.

  In the three-dimensional coordinate measuring apparatus 1 according to the present embodiment, in addition to the configuration of the second embodiment, a covering member is provided on the front side surface 10F and the rear side surface 10E of the surface plate 10. As shown in FIGS. 18, 19, and 20, each of the front side surface 10F and the rear side surface 10E of the surface plate 10 has a plate-shaped heat insulating member 150 as a covering member that covers substantially the entire surface. , 152 are fixed.

  This reduces the amount of heat flowing into and out of the surface plate 10 or the outside air from the front side surface 10F and the rear side surface 10E of the surface plate 10, so that even if the temperature of the outside air around the surface plate 10 (ambient temperature) changes. In addition, the temperature inside the surface plate 10 is hardly changed, and the deformation of the surface plate 10 is suppressed. Further, even if a temperature change occurs inside the surface plate 10 as described later, generation of a temperature gradient in the Y-axis direction is suppressed. Therefore, a decrease in the straightness of the Y carriage 14 is suppressed.

  In the present embodiment, since the front side surface 10F and the rear side surface 10E of the surface plate 10 are covered with the heat insulating members 150 and 152, the front side surface 10F and the rear side surface 10E of the surface plate 10 are thermally isolated from the outside air. Accordingly, the amount of heat flowing into and out of the surface plate 10 from the front side surface 10F and the rear side surface 10E of the surface plate 10 is reduced.

  Here, assuming that the surface plate 10 does not have the groove 40 and is not provided with the heat insulating members 150 and 152, the state of deformation of the surface plate 10 with respect to a change in ambient temperature will be described. .

  FIG. 21 shows how the platen 10 shrinks when the ambient temperature of the platen 10 decreases. When the ambient temperature decreases, the temperature of the surface plate 10 decreases from the peripheral portion prior to its inside. For this reason, the temperature distribution in the center of the surface plate 10 is higher than that in the peripheral region until the inside of the surface plate 10 stabilizes at a uniform temperature after the ambient temperature is lowered. During this time, the right side surface 10R and the left side surface 10L along the Y-axis direction of the surface plate 10 and the front side surface 10F and the rear side surface 10E along the X-axis direction are in a state in which an intermediate portion is bulged more outward than an end portion.

  Conversely, FIG. 22 shows how the platen 10 expands when the ambient temperature of the platen 10 increases. When the ambient temperature rises, the temperature of the surface plate 10 rises from the peripheral portion prior to its inside. Therefore, the temperature distribution in the central part of the surface plate 10 is lower than that in the peripheral part until the inside of the surface plate 10 is stabilized at a uniform temperature after the ambient temperature rises. During this time, the right side surface 10R and the left side surface 10L along the Y-axis direction of the surface plate 10 and the front side surface 10F and the rear side surface 10E along the X-axis direction are in a state in which the middle part is depressed inward from the end.

  Such deformation of the surface plate 10 causes a decrease in straightness of the right side surface 10R and the left side surface 10L along the Y-axis direction. Then, when the Y carriage 14 is moved in the Y axis direction with reference to the right side surface 10R, the Y carriage 14 swings in the yawing direction (direction around the Z axis), and the direction of the X guide 20 of the Y carriage 14 is changed to the X axis direction. Deviates from direction. For this reason, the measurement accuracy of the Y coordinate value of the Y carriage 14 is reduced.

  On the other hand, in the surface plate 10 of the present embodiment, the front side surface 10F and the rear side surface 10E are covered with the heat insulating members 150 and 152, so that the front side surface 10F and the rear side surface 10E flow into the inside of the surface plate 10 or outside air. The amount of heat entering and exiting is reduced. Therefore, a temperature change is hardly generated inside the surface plate 10 due to a decrease or increase in the ambient temperature, and even if a temperature change occurs, a temperature gradient in the Y-axis direction is suppressed.

  Therefore, the straightness of the Y guide 42 of the surface plate 10, that is, the straightness of the left side surface 42L, the right side surface 42R, the upper surface 42T, and the lower surface 42B of the Y guide 42 is suppressed regardless of the change in the ambient temperature.

  In the surface plate 10 of the present embodiment, the measurement area where the measurement target is placed and measurement is performed, and the area (guide area) of the Y guide 42 that guides the Y carriage 14 in the Y-axis direction are formed by grooves. Due to 40, it is discontinuous in the X-axis direction. Therefore, heat conduction between the measurement region and the guide region is suppressed, and heat generated near the guide region (Y guide 42), that is, heat generated by the Y drive mechanism, for example, Y The heat generated by the motor of the drive unit 80 of the drive mechanism or the frictional heat between the Y guide 42 and the air pads 62F, 62E, 64F, 64E, 66F, 66E68F, 68E, etc., flows into the measurement area via the guide area. Is suppressed.

  Therefore, a change in temperature in the measurement area of the surface plate 10 due to heat generated in the vicinity of the guide area is suppressed, and deformation of the measurement area of the surface plate 10 is suppressed. Then, the heat causes a temperature change in the guide area of the surface plate 10, and even if a temperature gradient occurs, the volume of the guide area is small, so that the deformation amount of the guide area is small and the straightness of the Y guide 42 is affected. Hardly occurs.

  From the above, the deformation of the surface plate 10 due to heat is suppressed, and the decrease in straightness of the Y guide 42 is suppressed, so that the Y carriage 14 is accurately moved in the Y-axis direction. Therefore, highly accurate measurement not affected by heat can be performed.

  A cover that covers the entire area of the Y guide 42 or the entire area of the Y guide 42 and the groove 40 is provided along the right side surface 10R of the surface plate 10 so that the guide region of the surface plate 10 is affected by changes in ambient temperature. The straightness of the Y guide 42 may be maintained so as not to be received. Further, when the temperature inside the cover rises due to the heat generated from the Y drive mechanism or the like, an exhaust unit may be provided to discharge the air inside the cover to the outside and keep the temperature inside the cover constant.

  Further, in the above embodiment, the heat insulating members 150 and 152 are provided on the front side surface 10F and the rear side surface 10E of the surface plate 10, but a heat insulating member may be provided on the left side surface 10L of the surface plate 10.

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

  Further, in the above-described embodiment, the case where the air pad (air bearing) is used as the support member that slidably contacts each surface of the Y guide 42 and the like has been described, but a type of support member other than the air pad may be used. Good. In addition, the arrangement of the support member slidably in contact with each surface of the Y guide 42 and the like and the arrangement of the driving unit 80 can be appropriately changed. The support members (air pads 66F and 66E) arranged inside the groove 40 may be slidably arranged on the inner surface of the groove 40 other than the right side surface 40R of the groove 40.

  The operation and effect of the three-dimensional coordinate measuring device 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 drive unit 80 is arranged in a 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, it does not bite dust, 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 (right side surface 10R) of the surface plate 10. Therefore, even if the surface plate 10 is slightly deformed, measurement can be performed with the surface plate 10 as a reference. If the roller 84 moves along another rail different from the platen 10, the roller 84 does not synchronize with the deformation of the platen 10 due to other factors such as thermal expansion of another rail.

  The air pads 64F, 64E, 66F, 66E are also arranged vertically along the side surface of the surface plate 10. Therefore, 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 right and left with respect to the traveling direction when the Y carriage 14 moves.

  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 also arranged in the vertical direction. Therefore, the yawing error and the vibration can be reduced without breaking the posture by sandwiching the front and rear with the air pad even in the case of a sudden drive.

  The distance (interval) between the support points P1 and P2 on the Y carriage 14 is sufficiently larger than 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 right and left with respect to the moving direction can be reduced.

  The air pads 66F and 66E are arranged perpendicular to the groove 40 side surface of the surface plate 10. Therefore, the groove 40 is formed in the surface plate 10, and the supporting points P1 and P2 by the air pads 66F and 66E are set as the side surfaces of the groove 40 of the surface plate 10, thereby following deformation such as thermal expansion of the surface plate 10, It can be measured with reference to the surface plate 10.

  Further, air pads 66F, 66E opposed to the support points P3, P4 by the air pads 64F, 64E are present as support points P1, 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 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) while using the side surface of the surface plate 10 as a reference. . Therefore, the sliding resistance on the driven side becomes negligible, and the yawing error is greatly reduced.

  On the driven side of the Y carriage 14, only the air pad 70 in the Z-axis direction is arranged, 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 any extra resistance on the driven side. As a result, vibration can be reduced and yawing can be reduced.

  The positions of the X guide 20 and the air pad 70 in the Z axis direction on the driven side of the left Y carriage 18 in the Y axis direction are determined by the air pads 66F, 66E (support points P1, P2) or the air pads 64F on the driving side of the left Y carriage 18. , 64E (support points P3, P4). Therefore, even in the case of rapid acceleration / deceleration, only the moment of the X guide 20 and the measuring unit is 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 effects 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 operation and effect.

  FIG. 23 is a front view (schematic front view) showing the appearance of the three-dimensional coordinate measuring apparatus 300 of Comparative Example 1 disclosed in Japanese Patent Application Laid-Open No. 5-322556. FIG. 24 is a sectional view (schematic sectional view) taken along line XXIV-XXIV in FIG. In the three-dimensional coordinate measuring apparatus 300 of Comparative Example 1, those having the same function or configuration as those of the three-dimensional coordinate measuring apparatus 1 of the present embodiment are denoted by the same reference numerals, and description thereof is omitted.

  As shown in FIGS. 23 and 24, 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, 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 disposed on the right side 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. The air pads 302T are provided at two positions along the Y direction (see FIG. 24).

  On the other hand, in the three-dimensional coordinate measuring apparatus 300 of Comparative Example 1, the left Y carriage 18 on the driven side (hereinafter, abbreviated as the driven side) that moves in the Y direction following the right Y carriage 16 on the driving side is connected to 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 platen 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 driving unit 301 has basically the same configuration as the driving unit 80 of the present embodiment, for example, and is provided near the air pad 302R. Note that a rectangular frame represented by a two-dot chain line in FIG. 24 indicates the position of the driving unit 301.

  In the three-dimensional coordinate measuring apparatus 300 of Comparative Example 1, an air pad 302R and an air pad 303L are arranged on both side surfaces (vertical surfaces on both sides) in FIG. In this case, although it seems that the Y carriage 14 is moved forward and backward in the Y direction at first glance, the yaw error is increased when the Y carriage 14 is moved 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 base 10, the right Y carriage 16 on the driving side and the left Y carriage 18 on the driven side control the main driving operation, and 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 between the right Y carriage 16 and the left Y carriage 18 in the Y direction is not constant. The error increases. For this reason, as in the present embodiment, it is preferable to move the right Y carriage 16 on the driving side along the Y guide 42 (see FIG. 3) and minimize the sliding resistance of the left Y carriage 18 on the driven side as much as possible. Since the left Y carriage 18 moves following the right Y carriage 16 on the driving side, the swing around the Z axis does not occur.

  Further, in the three-dimensional coordinate measuring apparatus 300 of Comparative Example 1, the driving unit 301 is not disposed near the driven-side air pad 303L, and further, the driven-side air pad 303L is moved with respect to the driving-side 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, the driven side air pad 303L is located on the opposite side of the platen 10 and away from the drive unit 301, so that the drive unit 301 is supported by sliding between the air pad 303L and the left side surface of the platen 10. , A large rotational moment is generated.

  Further, the air pad 302R and the air pad 303L are moved in a direction (Y direction) perpendicular to the pressing direction of the surface plate 10 while being pressed 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 yaw error remarkably worsens as the balance of the sliding resistance during the moving operation is slightly broken.

  As a method for reducing such yawing error, for example, Japanese Patent Application Laid-Open No. 7-218247 discloses a method of preventing the Y carriage 14 from twisting and bending even when the Y carriage 14 is moved at a large acceleration in the Y direction. It is disclosed to provide a possible specially configured drive. However, when the driving unit having this special structure is employed, there is a problem that the three-dimensional coordinate measuring device 300 becomes large and the structure of the driving unit becomes 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.

  Furthermore, in the three-dimensional coordinate measuring apparatus 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 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, the three-dimensional coordinate measuring apparatus 300 of Comparative Example 1 is not provided with an air pad facing the lower surface of the surface plate 10 or a Y guide (not shown) provided on the surface plate 10, so that the drive side The only part that determines the position of the right Y carriage 16 in the vertical direction (Z-axis direction) is the upper surface of the surface plate 10. For this reason, in the three-dimensional coordinate measuring apparatus 300 of Comparative Example 1, a pitching error other than the yawing error is also a problem.

  In order to reduce the pitching error, the positional relationship between the driving 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 driving 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 will tilt (swing) around the X axis. Therefore, 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 Comparative Example 1, the supporting point is only one point in the vertical direction. When driven by the drive unit 301, a rotational moment acts on 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 significant.

  When the Y carriage 14 (the right Y carriage 16) is simply supported 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 it is preferable that the sliding resistance of the right Y carriage 16 on the driving side is larger than that of the left Y carriage 18 on the driven side. Therefore, the sliding resistance cannot be balanced between 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 be deteriorated.

  Further, as in the three-dimensional coordinate measuring apparatus 300 of Comparative Example 1, the air pad 302T is disposed on the upper surface of the surface plate 10, but when the air pad is not disposed on the lower surface, the load of the Y carriage 14 is shifted to the right on the driving side. Both 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, the yawing error increases.

  In order to reduce the pitching error, the upper and lower surfaces of the surface plate 10 are sandwiched between air pads 62E, 62F, 68E, 68F (see FIG. 7) as in the three-dimensional coordinate measuring apparatus 1 of the present embodiment, and the upper and lower surfaces It is necessary to provide a driving unit 80 (see FIG. 7) between them. 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 become support points of the right Y carriage 16, and the position sandwiched between these two support points. Since the drive unit 80 is located at the position shown in FIG. 2, a pitching error hardly occurs even when the Y carriage 14 is accelerated and decelerated. In order to suppress pitching errors during acceleration and deceleration, the drive unit 80 must be located at the center of gravity of the Y carriage 14 (right Y carriage 16) in the Y direction, for example, at the center 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 the right Y carriage 16 has only one support point in the vertical direction. In addition to the pitching error, the right Y carriage 16 may swing around the Y axis, that is, a rolling error may occur. Even when such a rolling error occurs, the sliding resistance cannot be balanced between the left and right similarly to 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 apparatus 1 of the present embodiment, the air pads 62E, 62F, 68E, 68F (see FIG. 7) hold down not only the upper surface side but also the lower surface side of the surface plate 10. To support the right Y-carriage 16 vertically. For this reason, the sliding resistance of the right Y carriage 16 on the driving side increases, but the sliding resistance of the left Y carriage 18 on the driven side can be suppressed to a relatively small amount. At this time, by sandwiching the surface plate 10 in the vertical direction with the right Y carriage 16 on the driving side, it is possible to correct the forward and backward tilt (swing) of the Y carriage 14 in the Y direction and to reduce the weight applied to the Y carriage 14 by the driving side. It becomes possible to support almost in part.

  Further, the left Y carriage 18 on the driven side 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 centered on 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 moves the upper surface of the surface plate 10 to such an extent that the rolling error is reduced. Only 10T is enough to support lightly. As a result, no sliding resistance occurs on the driven left Y carriage 18, and as a result, the speed is determined by the sliding resistance of the driving right Y carriage 16, and a yawing error can be reduced.

  FIG. 25 is a front view (schematic front view) showing the appearance of a three-dimensional coordinate measuring apparatus 400 of Comparative Example 2 disclosed in JP-A-64-0353510 or JP-A-62-235502. . In the three-dimensional coordinate measuring apparatus 400 of Comparative Example 2, those having the same function or configuration as those of the three-dimensional coordinate measuring apparatus 1 of the present embodiment are denoted by the same reference numerals and description thereof is omitted.

  As shown in FIG. 25, in the three-dimensional coordinate measuring apparatus 400 of Comparative Example 2, the support portion 50 that supports the right Y carriage 16 on the drive side (the drive portion 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. The air pad 402R is disposed on the right side of the Y guide 42 of the surface plate 10, the air pad 402T is disposed on the upper side of the Y guide 42, the air pad 402L is disposed on the left side of the Y guide 42, and the air pad 402B is disposed on the Y guide 42. It is arranged on the lower surface side.

  Further, the three-dimensional coordinate measuring apparatus 400 of Comparative Example 2 has a driven left Y carriage 18L that moves in the Y direction following the driving right Y carriage 16 and a supporting portion 50L thereof. Here, the driven left Y-carriage 18L and support 50L and the drive-side right Y-carriage 16 and support 50 have a symmetrical shape.

  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 groove 40A and the Y guide 42A and the groove 40 and the Y guide 42 have left-right symmetric shapes. The above-described 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 (the base 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. Note that the three-dimensional coordinate measuring apparatus 400 of Comparative Example 2 may have a configuration in which an air pad is further disposed on the left side of the Y guide 42A.

  When the air pad 403T and the air pad 403B are disposed on the upper and lower surfaces of the Y guide 42A on the driven left Y carriage 18L, similarly to the drive right Y carriage 16, when the driven right Y carriage 16 and the driven left The sliding resistance increases with both the Y carriage 18L. As a result, also in the three-dimensional coordinate measuring apparatus 400 of the comparative example 2, when the Y carriage 14 is moved in the Y direction, the Y direction of the right Y carriage 16 and the left Y Is not constant, and swings, for example, about the Z axis, which may increase the yawing error.

  Therefore, in order to suppress the yawing error, it is preferable that the side that controls the main driving operation and the side that follows the operation be clearly divided, as in the three-dimensional coordinate measuring apparatus 1 of the present embodiment. That is, while the right Y carriage 16 on the driving side increases the sliding resistance and moves at least along the Y guide 42, the left Y carriage 18 on the driven side follows the driving side and follows the movement. It is preferable that the shape is supported by the minimum so as not to cause resistance.

  FIG. 26 is a front view (schematic front view) showing the appearance of the three-dimensional coordinate measuring apparatus 500 of Comparative Example 3. In the three-dimensional coordinate measuring apparatus 500 of Comparative Example 3, the same components and functions as those of the three-dimensional coordinate measuring apparatus 1 of the present embodiment are denoted by the same reference numerals, and description thereof is omitted.

  As shown in FIG. 26, the supporting portion 50 supporting the right Y carriage 16 on the driving side driven in the Y direction by the driving portion 501 is connected to the Y guide 42 (surface plate) via the air pads 502R, 502T, and 502L. Supported by 10). The air pad 502R is disposed on the right side of the Y guide 42 of the surface plate 10, the air pad 502T is disposed on the upper side of the Y guide 42, and the air pad 502L is disposed on the left side of the Y guide 42. The air pads 502R, 502T, and 502L are provided at two positions along the Y direction.

  In the three-dimensional coordinate measuring apparatus 500 of Comparative Example 3, 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 movably supported.

  The drive section 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 movable element 501B of a shaft-type linear motor fixed to the support unit 50, a stator (shaft) 501C arranged in parallel with the Y direction, and both ends of the stator 501C on the right side of the Y guide 42. And a fixing portion 501A for fixing the fixing portion 501A.

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

  In the three-dimensional coordinate measuring apparatus 500 of Comparative Example 3, since the air pad facing the lower surface of the surface plate 10 is not disposed as in Comparative Example 1, the right Y carriage 16 swings around the X axis. Pitching errors may occur significantly. Further, as described in Comparative Example 1, the sliding resistance of the right Y carriage 16 and the left Y carriage 18 cannot be balanced between the left and right due to the change due to the pitching error, and the load of the Y carriage 14 is reduced. 16 and the left Y carriage 18 are substantially equally divided. As a result, the yawing error may be deteriorated. 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 apparatus 1 of the present embodiment, and the upper and lower surfaces thereof are It is preferable to provide the driving unit 80 between them.

  In the three-dimensional coordinate measuring apparatus 500 of Comparative Example 3, the fixed part 501A and the stator 501C that constitute the drive part 501 of the shaft-type linear motor are provided on the right side of the Y guide 42 (platen 10). When the fixing portion 501A and the stator 501C are provided on the right side surface of the Y guide 42 (the platen 10) in this way, there is an error in the installation of the fixing portion 501A and the stator 501C with respect to the platen 10, and the respective thermal expansion coefficients. There is a possibility that the fixed portion 501A and the stator 501C may be distorted due to the bimetal effect resulting from the difference between the two. In this case, it is difficult to obtain measurement accuracy based on the surface plate 10. For this reason, as in the three-dimensional coordinate measuring apparatus 1 of the present embodiment, it is preferable to provide a drive unit 80 having a roller 84 that comes into contact with the right side surface of the Y guide 42 (surface plate 10).

  Furthermore, in the three-dimensional coordinate measuring apparatus 500 of Comparative Example 3, 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 target is disposed on the upper surface 10 T 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 of the stylus 28 is actually arranged 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 increases. . Further, the measurement accuracy of the Y coordinate value of the Y carriage 14 is apt to decrease due to the deflection of the Y carriage 14 in the yawing direction. Furthermore, when the scale 112 is installed on the periphery 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 errors due to expansion and contraction of the scale 112 itself are likely to occur.

  Therefore, as in the three-dimensional coordinate measuring apparatus 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 area where the measurement target is arranged on the upper surface 10T of the surface plate 10. It is preferable to shorten the distance from to the scale 112. That is, it is preferable to arrange the left Y carriage 18 on the driven side, the measurement area, the scale 112, and the right Y carriage 16 on the driving side (the driving unit 80) in this order. In this manner, by providing the scale 112 on the driving side (the right Y carriage 16 side) and at a location close to the measurement area, even if there is a yawing error, the error can be minimized. When a 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 part) of the surface plate 10, the dust does not ride on the scale 112, and An erroneous reading of the scale 112 due to dust or dust does not occur.

  FIG. 27 is a front view (schematic front view) showing the appearance of the three-dimensional coordinate measuring apparatus 1 of the present embodiment. FIG. 28 is a cross-sectional view (cross-sectional schematic view) along the line XXVIII-XXVIII in FIG. FIG. 29 is a top view showing the top surface 10T of the surface plate 10, and is a diagram showing the arrangement of each air pad provided on the Y carriage 14 and the drive unit 80. A rectangular frame indicated by a two-dot chain line in FIG. 28 indicates the position of the drive unit 80.

  As shown in FIGS. 27 to 29, the three-dimensional coordinate measuring apparatus 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 apparatus 1 of the present embodiment, the division of the right Y carriage 16 on the driving side and the left Y carriage 18 on the driven side that follows (moves) the operation of the right Y carriage 16 is performed. The sliding resistance of the left Y-carriage 18 on the driven side is made as small as possible (a left-right asymmetric 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.

  The second difference is that, 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 sandwich the driving unit 80. Air pads are arranged on the left, right, front and back. As a result, a pitching error and a rolling error that lead to a worsening of the yawing error can be reduced.

  That is, in the three-dimensional coordinate measuring apparatus 1 of the present embodiment, in order to reduce the yawing error, the right Y carriage 16 on the driving side sandwiches the upper, lower, left, and right sides of the surface plate 10 (Y guide 42). Further, air pads 62E, 64E, 66E, 68E and air pads 62F, 64F, 66F, 68F are arranged before and after the driving section 80 in the Y direction with the driving section 80 as the center. In addition, the driven-side air pad 70 is disposed only on the upper surface side of the surface plate 10, and is disposed between the front and rear spaces of each driving-side air pad in the Y direction. As a result, the sliding resistance concentrates on the driving side, and the driven side merely supports.

  Further, as shown in FIG. 29, the driven side air pad 70 is positioned substantially opposite to the surface plate 10 with respect to the driving unit 80, and is connected to a line LX connecting the driven side air pad 70 and the driving unit 80, What is necessary is just to make it perpendicular to the line LY connecting the two pairs of air pads existing before and after the portion 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 driven-side air pad 70 is also provided at an intermediate point between the two pairs of air pads on the driving side.

  As a third different point, in the three-dimensional coordinate measuring apparatus 1 of the present embodiment, a driving unit 80 having a roller 84 which is in contact with the right side surface of the Y guide 42 (the base 10) is provided. Thus, unlike Comparative Example 3, it is possible to prevent the installation error of the driving unit 80 and to prevent the driving unit 80 from being distorted due to the bimetal effect, so that the measurement accuracy based on the surface plate 10 is improved. can get.

  As a difference 4, in the three-dimensional coordinate measuring apparatus 1 of the present embodiment, the scale 112 is provided on the left side surface 40L of the groove 40, and the scale 112 is provided on the upper surface 10T of the surface plate 10 from the measurement area where the measurement target is arranged. 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 another method.

  FIG. 30 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-described embodiment. As shown in FIG. 30, the right end (the end facing the right Y carriage 16) of the upper surface 10 </ b> T of the surface plate 10 is a convex provided 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. It should be noted that 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 three-dimensional coordinate measuring apparatus 1A includes a Y guide 42Z.

  Thus, it is also possible to form the Y guide 42Z by the convex portion. Here, for example, when the Y guide 42Z is formed of a different material from the surface plate 10, 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, when the surface plate 10 is slightly warped, there is a possibility that the measurement based on the surface plate cannot be performed. For this reason, as described in the above embodiment, it is preferable that the Y guide 42 be formed by the groove 40.

  DESCRIPTION OF SYMBOLS 1 ... Three-dimensional coordinate measuring device, 10 ... Surface plate, 10B, 20B, 42B, 202B ... Lower surface, 10R, 24R, 40R, 42R, 250R ... Right side surface, 10T, 20T, 42T, 202T ... Upper surface, 12 ... Stand, 14 ... Y carriage, 16 ... Right Y carriage, 18 ... Left Y carriage, 20 ... X guide, 20E, 24E, 202E, 250E ... Back surface, 20F, 24F, 202F, 250F ... Front surface, 22 ... Z column, 24 ... Z Carriage, 24L, 40L, 42L, 250L ... left side surface, 26 ... measuring probe, 28 ... stylus, 40 ... groove, 40B ... bottom surface, 42 ... Y guide, 50, 200 ... support portion, 52 ... base end portion, 54 ... Right part, 56 ... Left part, 58 ... Tip part, 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, 130L, left rail, 130R, right rail, 132L, 132R, guide groove, 134, 134E, 134F, bellows cover, 150, 152, heat insulating member, 202, X guide insertion hole, 250, Z carriage Insertion hole

Claims (2)

A surface plate having upper and lower surfaces and side surfaces, on which a measurement object is placed,
A gate-shaped Y carriage that supports the measurement probe and is movable in the Y-axis direction of the surface plate across the surface plate, and a Y carriage supported on the surface plate by two support members,
The two support members include a first support member having a drive mechanism for driving the Y carriage in the Y-axis direction, and a second support member that moves following the first support member.
The surface plate is a guide having two side surfaces perpendicular to the upper surface of the surface plate on the first support member side, and has a guide extending in the Y-axis direction,
The first support member is slidably supported on the upper surface of the guide, and the first support member sandwiches the two side surfaces of the guide from right and left at two places along the Y-axis direction . Having side support members of
The three-dimensional coordinate measuring device wherein the position in the Y-axis direction of the drive mechanism and the Y carriage that abuts one of the two side surfaces is between the two pairs of side surface support portions.   The three-dimensional coordinate measuring device according to claim 1, wherein the guide is a part of the surface plate.

Images