JP2021092590A - Three-dimensional coordinate measurement device - Google Patents

Abstract

To provide a three-dimensional coordinate measurement device capable of suppressing oscillation of a Y-carriage and improving measurement accuracy.SOLUTION: A three-dimensional coordinate measurement device comprises: a surface plate; and a Y-carriage which is supported on the surface plate by two column members. The two column members include a first column member having a drive mechanism for driving the Y-carriage in a Y-axis direction, and a second column member that follows the first column member. The surface plate comprises a guide having two side surfaces vertical to a top surface of the surface plate on the first column member side, the two side surfaces being formed of a side surface of the surface plate and a side surface of a groove formed in the surface plate in the Y-axis direction, and the guide extending in the Y-axis direction. The first column member is slidably supported on the top surface of the guide, the first column member has two pairs of vertical side surface supporting members for holding the guide from above and below and from left and right. The drive mechanism has a roller and a motor for rotating the roller.SELECTED DRAWING: Figure 3

Description

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

In a general three-dimensional coordinate measuring device, a Y carriage that is movable in the front-rear direction (Y-axis direction) is arranged on the upper part of a surface plate on which a measurement object is placed. The Y carriage has a columnar X guide spanned along the left-right direction (X-axis direction), and the X-carriage is movably supported by the X guide in the X-axis direction. A columnar Z-carriage along the vertical direction (Z-axis direction) is movably supported in the X-carriage in the Z-axis direction, and a measurement probe is attached to the lower end of the Z-carriage. As a result, the stylus of the measuring probe is movably supported in the three axial directions of the X, Y, and Z axes (see Patent Documents 1 to 3 and the like).

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

JP-A-2007-33052 Japanese Unexamined Patent Publication No. 7-139936 Japanese Unexamined Patent Publication No. 7-167641

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

However, in Patent Document 1, since the Y carriage is supported by a structure in which the entire width of the surface plate is sandwiched between the three air pads of the Y carriage, it is strong in the left-right direction but weak in the front-back direction. There is a problem that runout in the direction around the Z axis (yawing direction) is likely to occur.

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

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 device capable of suppressing the runout of the Y carriage and improving the measurement accuracy. And.

Further, in the above-mentioned three-dimensional measuring device, the measurement of the position (Y coordinate value) of each point of 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 Y of the Y carriage. This is done by measuring the axial position (Y coordinate value). A linear encoder is used as a position detecting means for measuring the Y-axis coordinate value of the Y carriage. The scale (member on which the scale is formed) in the linear encoder is often provided on a surface plate portion near a drive unit provided on the Y carriage as described in Patent Document 2. Further, as described in Patent Document 3, if the Y guide is a Y guide that movably supports the Y carriage in the Y axis direction and is provided with a Y guide that is a member different from the surface plate, the Y guide is provided. Some scales are installed.

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

Further, even when the scale is installed on the surface plate, conventionally, since the scale is installed on the peripheral edge of the surface plate such as the 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 long with a support column portion erected along the Z-axis direction of the Y carriage interposed between the measurement area and the measurement area.

On the other hand, the Y carriage (X guide spanned to the left and right) is arranged along the X axis direction, but the direction of the X guide deviates from the X axis direction due to the deflection of the Y carriage in the yawing direction (direction around the Z axis). The longer the distance from the measurement area to the scale, the more the measurement obtained from the Y coordinate value of the position where the stylus of the measurement probe is actually placed in the measurement area and the Y coordinate value of the Y carriage measured by the scale. The difference from the Y coordinate value of the child becomes large.

Therefore, if the distance from the measurement area to the scale is long as in the conventional case, 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, is increased due to the yawing direction of the Y-carriage. It is easy to cause a decrease.

Further, when the scale is installed on the peripheral edge of the surface plate, the scale is easily affected by the ambient temperature because the scale is close to the outside air, and an error due to expansion and contraction of the scale itself is likely to occur.

The present invention has been made in view of such circumstances, and is a three-dimensional coordinate measuring device for improving 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 object to be measured. The second purpose is to provide.

Further, in the above-mentioned three-dimensional coordinate measuring device, Patent Document 1 states that the left and right side surfaces of the surface plate and the upper surface of the surface plate along the left and right side surfaces support the Y carriage via an air pad (air bearing). 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 the straightness of the surface plate surface due to deformation of the surface plate or vibration, the granite has a high hardness and a large specific gravity as a surface plate. And stone materials such as marble are used.

On the other hand, since the heat conductivity of a stone surface plate is low, it is difficult for heat to be transferred to the inside, and when the temperature of the outside air around the surface plate (ambient temperature) changes, the inside of the surface plate becomes a uniform temperature. A temperature gradient occurs over a long period of time. When such a temperature gradient occurs, there is a problem that the surface plate is deformed and the straightness of the surface plate surface (upper surface, side surface, etc.) is lowered, resulting in a decrease in 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 the straightness of the left and right side surfaces causes an error in the support angle of the Y carriage, which greatly affects the measurement result.

Therefore, Patent Document 1 discloses that the surface of a surface plate that is not used as a guide for the Y carriage, that is, the front and rear side surfaces are 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, the generation of the temperature gradient in the Y-axis direction is suppressed even if the ambient temperature changes and a temperature gradient is generated inside the surface plate. .. Therefore, the decrease in straightness on the left and right sides of the surface plate is suppressed regardless of the change in the ambient temperature, and the decrease in measurement accuracy is suppressed.

By the way, as in Patent Document 1, in the area of the surface plate, a measurement area on which a measurement object is placed and measurement is performed and a guide area for guiding the Y carriage in the Y-axis direction are integrally formed. If so, the heat generated by the motor of the Y drive mechanism that moves the Y carriage in the Y-axis direction flows into the measurement region through the guide region.

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

Therefore, even if the front and rear side surfaces of the platen are covered with a heat insulating member as in Patent Document 1 to suppress the generation of a temperature gradient in the Y-axis direction of the platen due to the influence of the ambient air temperature, it is generated by the Y drive mechanism. Heat can create a temperature gradient in the Y-axis direction. In this case, the straightness of the surface of the guide portion is lowered, and the measurement accuracy is lowered.

The present invention has been made in view of such circumstances, and a third object of the present invention is to provide a three-dimensional coordinate measuring device capable of suppressing deformation of a surface plate due to heat and performing highly accurate measurement. To do.

The three-dimensional coordinate measuring device for achieving the object of the present invention has upper and lower surfaces and side surfaces, and supports a surface plate on which a measurement object is placed and a measurement probe, and Y of the surface plate straddling the surface plate. It is a gate-shaped Y carriage that can move in the axial direction, and includes a Y carriage that is supported by a surface plate by two support members, and the two support members are drive mechanisms that drive the Y carriage in the Y-axis direction. The surface plate has a first strut member having a surface plate and a second strut member that moves following the first strut member, and the surface plate is a pair of pairs perpendicular to the upper and lower surfaces of the surface plate on the first strut member side. The first strut member having two side surfaces is supported by the surface plate at least one of a vertical support member that sandwiches the surface plate in the vertical direction and a side support member that sandwiches the pair of two side surfaces, and the second strut member. Is supported by a top surface support member on the top surface of the surface plate.

According to this 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. In addition, pitching error and rolling error, which lead to deterioration of yawing error, can be reduced. As a result, the runout of the Y carriage can be suppressed.

In the three-dimensional coordinate measuring device according to another aspect of the present invention, when the side surface of the surface plate on the first support column member side is the first side surface, the first side surface side of the upper surface of the surface plate is in the Y-axis direction. A groove is formed along the groove, and the first strut member is slidably arranged on the first side surface and the inner surface of the groove, and the inner surface of the groove is a second along the Y-axis direction facing each other. The second side surface is formed closer to the first side surface than the third side surface, and the second side surface is the first side surface and the second side surface. It is composed of. By forming two sides with grooves formed on the surface plate, measurement accuracy based on the surface plate can be obtained.

In the three-dimensional coordinate measuring device according to another aspect of the present invention, when the first support member is supported by the surface plate by at least the side support member, the side support member is slidably arranged 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 arranged on the other side of the two side surfaces, 2 along the Y-axis direction. It has a third support member and a fourth support member provided at a location, and the first support member and the third support member, and the second support member and the fourth support member have each other. It is located at the opposite position. As a result, the swing (yawing error) of the Y carriage around the Z axis can be suppressed.

In the three-dimensional coordinate measuring device according to another aspect of the present invention, when the first support member is supported by the surface plate by at least the upper and lower support members, the upper and lower support members are slidably arranged on the upper surface of the surface plate. The fifth support member and the sixth support member provided at two locations along the Y-axis direction are slidably arranged on the lower surface of the surface plate, and 2 along the Y-axis direction. It has a seventh support member and an eighth support member provided at a location, and the fifth support member and the seventh support member, and the sixth support member and the eighth support member have each other. It is located at the opposite position. As a result, the swing (pitching error) around the X-axis of the Y carriage is suppressed.

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

In the three-dimensional coordinate measuring device according to another aspect of the present invention, the distance between the two Y-axis directions is larger than the distance between the two side surfaces. As a result, 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 drive mechanism includes a roller that abuts on one of the two side surfaces and a motor that rotates the roller.

In the three-dimensional coordinate measuring device according to another aspect of the present invention, the Y carriage is provided with a scale arranged along the Y-axis direction on the surface plate at a position between the first strut member and the second strut member. A position detecting means for detecting a position in the Y-axis direction is provided. As a result, the distance from the measurement area where the object to be measured is placed 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 area and the first support column member, a portion closer to the measurement area (that is, closer to the work). The scale can be read by (part). That is, since the scale can be read at a position where the yawing error is smaller than that on the drive side (first strut member, drive mechanism), the measurement accuracy can be further improved.

In the three-dimensional coordinate measuring device according to another aspect of the present invention, when the side surface on the side of the first support column member of the surface plate is set as the first side surface, the side surface on the upper surface of the surface plate is on the side of the first side surface. A groove is formed along the Y-axis direction, and the first strut member is slidably arranged on the first side surface and the inner surface of the groove, and the inner surface of the groove is along the Y-axis direction facing each other. It has 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. To. As a result, the distance from the measurement area where the measurement object is placed 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 the expansion and contraction of the scale is suppressed. As a result, the measurement accuracy can be improved.

Further, the scale is attached to a third side surface of the surface plate, that is, a vertical surface perpendicular to the upper surface of the surface plate. Therefore, even if dust or dirt falls from the upper part (upper side) of the surface plate, it will not get on the scale and the scale reading will not malfunction due to the dust or dirt.

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

The three-dimensional coordinate measuring device according to another aspect of the present invention includes a heat insulating member that covers the side surface of the surface plate along the X-axis direction. As a result, the heat entering and exiting the inside of the surface plate or the outside air from the side surface 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 inside the surface plate is less likely to change. , Deformation of the surface plate is suppressed. Further, even if a temperature change occurs inside the surface plate, the generation of a temperature gradient in the Y-axis direction is suppressed, so that at least a decrease in the straightness of the first side surface is suppressed, and the Y-carriage is moved in the Y-axis direction. The movement is done 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 surface support members, and the upper surface 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 device of the present invention, the measurement accuracy can be improved by suppressing the runout 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 object to be measured.

According to the three-dimensional coordinate measuring device of the present invention, deformation of the surface plate due to heat can be suppressed and highly accurate measurement can be performed.

Perspective view showing the appearance of the three-dimensional coordinate measuring device to which the present invention is applied (first embodiment). Front view showing the appearance of the three-dimensional coordinate measuring device to which the present invention is applied. Front view showing the right side of the surface plate enlarged Right side view showing the right side of the surface plate enlarged Perspective view showing the Y carriage with the cover removed It is the top view which showed the upper surface of the surface plate, and is the figure which showed the arrangement with respect to the surface plate of the air pad provided in the Y carriage (first embodiment). It is the right side view which showed the right side surface of the surface plate, and is the figure which showed the arrangement with respect to the surface plate of the air pad provided in the Y carriage (first embodiment). Front view showing the groove part of the surface plate enlarged Perspective view showing the Z column removed from the X guide Perspective view showing the Z column removed from the X guide Perspective view showing the Z column removed from the X guide Perspective view showing the support part of the Z column removed from the X guide. Perspective view showing the support part of the Z column removed from the X guide. Schematic diagram showing the positional relationship of the support points where the Y guide of the surface plate supports the Y carriage from the upper surface side of the surface plate. Schematic diagram showing the positional relationship of the support points where the Y guide of the surface plate supports the Y carriage from the right side of the surface plate (first embodiment). It is the perspective view which showed the groove part of the surface plate enlarged, and showed the 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 measurement object is placed from the upper surface side of the surface plate (second embodiment). form) Perspective view showing the appearance of the three-dimensional coordinate measuring device to which the present invention is applied (third embodiment). It is the top view which showed the upper surface of the surface plate, and is the figure which showed the arrangement with respect to the surface plate of the air pad provided in the Y carriage (third embodiment). It is the right side view which showed the right side surface of the surface plate, and is the figure which showed the arrangement with respect to the surface plate of the air pad provided in the Y carriage (third embodiment). The figure which showed the state of the shrinkage of the surface plate when the ambient temperature drops. The figure which showed the state of the shrinkage of the surface plate when the ambient temperature rises Front view showing the appearance of the three-dimensional coordinate measuring device of Comparative Example 1 (schematic front view) Sectional view along line XXIV-XXIV in FIG. 23 (schematic sectional view) Front view showing the appearance of the three-dimensional coordinate measuring device of Comparative Example 2 (schematic front view) Front view showing the appearance of the three-dimensional coordinate measuring device of Comparative Example 3 (schematic front view) Front view (schematic front view) showing the appearance of the three-dimensional coordinate measuring device 1 of the present embodiment. Sectional view along line XXVIII-XXVIII in FIG. 27 (schematic sectional view) It is the top view which showed the upper surface of the surface plate, and is the figure which showed the arrangement of each air pad provided in a Y carriage, and a drive part. Front view showing the appearance of the three-dimensional coordinate measuring device of another embodiment (frontal schematic view)

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

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

The three-dimensional coordinate measuring device 1 shown in these figures has a surface plate 10 supported on an installation surface (floor surface) via a gantry 12. The surface plate 10 is integrally formed in a rectangular shape with a stone material such as 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. The surface plate 10 is not limited to the 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 strut member that extends along the Z-axis direction on each of the right side and the left side (one side) of the surface plate 10 when the surface plate 10 is viewed from the front side. A right Y carriage 16 and a left Y carriage 18 which is a second support column member, and a columnar X guide 20 which is bridged over the upper ends of the right Y carriage 16 and the left Y carriage 18 and extends along the X axis direction. Has.

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

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

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

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

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

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

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

First, the supporting means (Y guide mechanism, two strut members) of the Y carriage 14 in the Y drive mechanism will be described.

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

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

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

The grooves 40 include a right side surface 40R (corresponding to the second side surface of the present invention) and a left side surface 40L (corresponding to the third side surface of the present invention) perpendicular to the X axis facing each other, and a bottom surface 40B perpendicular to the Z axis. And have.

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

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

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

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

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

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

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

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

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

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

In these figures, the two air pads 62F and 62E (corresponding to the upper and lower support members of the present invention) arranged along the upper surface 42T of the Y guide 42 are along the Y-axis direction at the base end portion 52 of the support portion 50. It is provided at two positions (two points on a straight line parallel to the Y axis), and is arranged downward facing 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 locations (Y-axis) along the Y-axis direction on the right side portion 54 of the support portion 50. It is provided at two positions on a straight line parallel to the above, and is arranged to the left facing the right side surface 42R of the Y guide 42.

The two air pads 66F and 66E (corresponding to the 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 located in the left side portion 56 of the support portion 50 in the Y-axis direction. It is provided at two positions along the line (two points on a straight line parallel to the Y axis), and is arranged to face the left side surface 42L of the Y guide 42 and face the right side. 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.

The two air pads 68F and 68E (see FIGS. 3 and 7, corresponding to the upper and lower support members of the present invention) arranged along the lower surface 42B of the Y guide 42 are located along the Y-axis direction at the tip end 58 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 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.

The air pad 70 (corresponding to the upper surface support member of the present invention) arranged on the upper surface near the left side surface of the surface plate 10 is provided at the lower end portion of the left Y carriage 18 and faces downward toward the upper surface 10T of the surface plate 10. Is placed in.

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

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

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

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

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

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

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

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

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

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

As shown in FIG. 4, a drive unit 80 is provided on the right side portion 54 of the support unit 50. As shown in FIGS. 6 and 7, the drive unit 80 is arranged at a position substantially intermediate between the two air pads 64F and 64E provided on the right side portion 54 of the support unit 50. The drive unit 80 may be arranged on the left side portion 56 of the support portion 50 and at a position substantially intermediate between the two air pads 66F and 66E.

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

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

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

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

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

FIG. 8 is an enlarged front view showing a portion of the groove 40 of the surface plate 10. As shown in the figure, on the left side surface 40L of the groove 40, for example, a long plate-shaped scale 112 constituting an optical linear encoder 110 and provided with a grid scale is installed along the Y-axis direction. (See FIG. 6).

On the other hand, on the left side portion 56 of the support portion 50, an optical sensor 114 constituting the linear encoder 110 is installed with a support member and arranged at a position facing the scale 112 (see FIG. 6). Then, a detection signal corresponding to the grid scale of the scale 112 formed at a position facing the optical sensor 114 is output from the optical sensor 114.

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

Next, in the three-dimensional coordinate measuring device 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 object to be measured. A configuration for improving the measurement accuracy of the value will be described. In the description of the second embodiment, the same reference numerals are given to the configurations common to those of the first embodiment, and the description thereof will be omitted.

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

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

As shown in the figure, the right rail 130R and the left rail 130L are fixedly arranged on the surface plate 10 at the right edge portion and the left edge portion 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 back end (rear end) of the groove 40, and the right rail 130R extends from the right side surface 40R (Y guide 42) of the groove 40. The left rail 130L is provided along the left side surface 40L of the groove 40 (see FIG. 6).

Further, the right rail 130R and the left rail 130L have symmetrical shapes, and each of them is provided with guide grooves 132R and 132L having lateral openings and openings in the directions facing each other.

Then, in the upper opening of the groove 40, a telescopic bellows cover 134 supported by fitting the left and right edge portions into the guide groove 132R of the right rail 130R and the guide groove 132L of the left rail 130L is installed.

The bellows cover 134 is separately installed on the front bellows cover 134F and the rear bellows cover 134E (see FIG. 1) with the left side 56 of the support portion 50 of the right Y carriage 16 interposed therebetween, and is installed on the front side. The front end of the bellows cover 134F is fixed to the front side surface of the surface plate 10 via a fixing member (such as a covering member that covers the front side surface of the surface plate 10), and the rear end is the left side portion of the support portion 50. It is fixed to the front of 56. 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 covering the rear side surface of the surface plate 10 (covering the rear side surface of the surface plate 10). It is fixed to the surface plate 10 via a covering member or the like.

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

As a result, the outside air is prevented from directly hitting the scale 112 installed inside the groove 40, the temperature change inside the groove 40 can be suppressed, and the scale 112 expands and contracts due to the temperature change of the outside air. Is prevented.

Further, dust and dirt are prevented from entering the inside of the groove 40, and dust and the like adhere to the scale 112, which causes a measurement error due to a reading error of the grid scale, and is arranged inside the groove 40. It is possible to prevent a situation in which 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 device 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 object to be measured. The effect of improving the above will be explained.

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 and the scale 112 in the linear encoder 110 and the measurement area where the measurement object is arranged. It is a schematic diagram shown from the side.

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

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

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 closer to the measurement region than the air pads 64F, 64E, 66F, 66E, and the drive unit 80 of the Y carriage 14 (right Y carriage 16).

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 area and the scale 112, and the distance from the measurement area to the scale 112 is short.

Therefore, even if the direction of the X guide 20 of the Y carriage 14 deviates from the X axis direction due to the deflection of the Y carriage 14 in the yawing direction (direction around the Z axis), the stylus 28 of the measurement probe 26 in the measurement region remains. The difference between the Y coordinate value of the position actually arranged and the Y coordinate value of the stylus 28 obtained from the Y coordinate value of the Y carriage 14 actually measured by the scale 112 (linear encoder 110) becomes small.

Therefore, even when the Y carriage 14 is shaken 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 object to be measured can be 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 the support points P3 and P4 as auxiliary support points and becomes one support point P0 of the right side surface 42R. , It is stable in a state of being supported by two support points P1 and P2 on the left side surface 42L. As a result, the Y carriage 14 is less likely to swing in the yawing direction.

Further, since the scale 112 is installed on the surface plate 10, the influence of thermal deformation of the Y guide and the surface plate and Y are compared with the case where the scale 112 is installed on a Y guide or the like separate from the surface plate 10. The measurement accuracy does not decrease due to the instability of the joint with the guide. Therefore, high measurement accuracy can be continuously maintained.

Further, since the scale 112 is not provided on the peripheral edge of the surface plate 10 (right side surface 10R, left side surface 10L, etc.) but is arranged inside the surface plate 10, the influence of the temperature change of the outside air is small, and the scale 112 The decrease in accuracy due to expansion and contraction of the surface plate is suppressed. In particular, since the bellows cover 134 is installed in the upper opening of the groove 40 as described above to shield the inside of the groove 40 from the outside air, it is prevented that the outside air directly hits the scale 112, and the groove 40 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 the temperature changes, and an inexpensive one can be used.

Further, in the above embodiment, the scale 112 is installed on the left side surface 40L of the groove 40, but on 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 it, 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 covering member of a type other than the bellows cover may be used. For example, a covering member made of an elastic material can cover the upper openings of the front and rear grooves 40 of the lower end portion (left side portion 56 of the support portion 50) of the Y carriage 14 that fits into the groove 40. .. Further, 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. An insertion passage such as a notch in the above, which is closed except when the lower end portion of the Y carriage 14 is inserted, may be formed along the groove 40 (Y-axis direction). Further, a covering member for covering the upper opening of the groove 40 may not be provided.

Further, in the above embodiment, as the position detecting means of the Y carriage 14 for measuring the Y coordinate value of the Y carriage 14, the position detecting means of the Z column 22, and the position detecting means of the Z carriage 24, an optical linear encoder and Although the form using the scale is shown, not only the optical type but also other types of linear encoders and scales such as the magnetic type can be used.

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

In the three-dimensional coordinate measuring device 1 according to the present embodiment, in addition to the configuration of the second embodiment, covering members are 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 of the surface plate 10. , 152 are fixed.

As a result, the amount of heat that enters and exits the inside or outside air of the surface plate 10 from the front side surface 10F and the rear side surface 10E of the surface plate 10 is reduced, so that even if the temperature (ambient temperature) of the outside air around the surface plate 10 changes. , The temperature change inside the surface plate 10 is less likely to occur, 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, the generation of a temperature gradient in the Y-axis direction is suppressed. Therefore, the 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 shielded from the outside air. Therefore, the amount of heat entering and exiting the inside or outside air 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 a surface plate 10 in which the groove 40 is not formed and the heat insulating members 150 and 152 are not provided, 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 surface plate 10 contracts when the ambient temperature of the surface plate 10 decreases. When the ambient temperature drops, the temperature of the surface plate 10 drops from the peripheral portion prior to the inside of the surface plate 10. Therefore, the central portion of the surface plate 10 has a higher temperature distribution than the peripheral portion from the time when the ambient temperature drops until the inside of the surface plate 10 stabilizes at a uniform temperature. During this period, 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 intermediate portions thereof bulge outward from the end portions.

On the contrary, FIG. 22 shows how the surface plate 10 expands when the ambient temperature of the surface plate 10 rises. When the ambient temperature rises, the temperature of the surface plate 10 rises from the peripheral portion prior to the inside thereof. Therefore, the central portion of the surface plate 10 has a lower temperature distribution than the peripheral portion from the time when the ambient temperature rises until the inside of the surface plate 10 stabilizes at a uniform temperature. 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 where the intermediate portions thereof are dented inward from the end portions.

Such deformation of the surface plate 10 causes a decrease in the 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 the X axis. It deviates from the direction. Therefore, the measurement accuracy of the Y coordinate value of the Y carriage 14 is lowered.

On the other hand, in the surface plate 10 of the present embodiment, since the front side surface 10F and the rear side surface 10E are covered with the heat insulating members 150 and 152, the front side surface 10F and the rear side surface 10E are directed to the inside or the outside air of the surface plate 10. The amount of heat that goes in and out is reduced. Therefore, the temperature change is less likely to occur inside the surface plate 10 due to the decrease or increase in the ambient temperature, and even if the temperature change occurs, the generation of the temperature gradient in the Y-axis direction is suppressed.

Therefore, regardless of the change in the ambient temperature, the straightness of the Y guide 42 of the surface plate 10, that is, the decrease in 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.

Further, in the surface plate 10 of the present embodiment, the measurement area on which the object to be measured is placed and the 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 grooved. By 40, it is discontinuous in the X-axis direction. Therefore, heat conduction between the measurement region and the guide region is suppressed, and the heat generated in the vicinity of the guide region (Y guide 42), that is, the heat generated by the Y drive mechanism, for example, Y. Heat generated by the motor or the like of the drive unit 80 of the drive mechanism, frictional heat between the Y guide 42 and the air pads 62F, 62E, 64F, 64E, 66F, 66E68F, 68E, etc. flow into the measurement area through the guide area. Is deterred.

Therefore, the heat generated in the vicinity of the guide region suppresses the temperature change in the measurement region of the surface plate 10, and the deformation of the measurement region of the surface plate 10 is suppressed. Then, the heat causes a temperature change in the guide region of the surface plate 10, and even if a temperature gradient occurs, the volume of the guide region is small, so that the amount of deformation of the guide region is small, which affects the straightness of the Y guide 42. Is almost non-existent.

From the above, deformation of the surface plate 10 due to heat is suppressed, and deterioration of the straightness of the Y guide 42 is suppressed, so that the Y carriage 14 is moved in the Y-axis direction with high accuracy. Therefore, highly accurate measurement that is not affected by heat is possible.

A cover is provided along the right side surface 10R of the surface plate 10 to cover the entire area of the Y guide 42 or the entire area of the Y guide 42 and the groove 40, and the guide area of the surface plate 10 is affected by the change in ambient temperature. The straightness of the Y guide 42 may be maintained so as not to receive the temperature. Further, when the temperature inside the cover rises due to the heat generated from the Y drive mechanism or the like, an exhaust means may be provided to discharge the air inside the cover to the outside to 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 the heat insulating member may also be provided on the left side surface 10L of the surface plate 10.

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

Further, in the above embodiment, the case where an air pad (air bearing) is used as a support member that slidably contacts each surface of the Y guide 42 or the like is shown, but a support member of a type other than the air pad may also be used. Good. Further, the arrangement of the support member that slidably contacts each surface of the Y guide 42 and the like and the arrangement of the drive unit 80 can be appropriately changed. The support members (air pads 66F, 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 effects of the above three-dimensional coordinate measuring device 1 will be supplementarily described below.

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

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

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

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

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

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

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

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

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

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

FIG. 23 is a front view (frontal schematic view) showing the appearance of the three-dimensional coordinate measuring device 300 of Comparative Example 1 disclosed in JP-A-5-31256. Further, FIG. 24 is a cross-sectional view (cross-sectional schematic view) along the line XXIV-XXIV in FIG. 23. In the three-dimensional coordinate measuring device 300 of Comparative Example 1, those having the same function or configuration as the three-dimensional coordinate measuring device 1 of the present embodiment are designated by the same reference numerals and the description thereof will be omitted.

As shown in FIGS. 23 and 24, in the three-dimensional coordinate measuring device 300 of Comparative Example 1, the support portion 50 that supports the right Y carriage 16 on the side directly driven by the drive unit 301 (hereinafter, abbreviated as the drive side). Is supported by the surface plate 10 via the air pad 302R and the air pad 302T. The air pad 302R is arranged on the right side surface of the surface plate 10, and the air pad 302T is arranged on the right end side of the upper surface 10T of the surface plate 10. Further, the air pads 302T are provided at two positions along the Y direction (see FIG. 24).

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

The drive unit 301 has basically the same configuration as the drive unit 80 of the present embodiment, and is provided in the vicinity of the air pad 302R. The rectangular frame represented by the alternate long and short dash line in FIG. 24 indicates the position of the drive unit 301.

In the three-dimensional coordinate measuring device 300 of Comparative Example 1, the air pads 302R and the air pads 303L are arranged on both side surfaces (vertical surfaces on both sides) of the surface plate 10 in FIG. 23. In this case, it seems to be stable in moving the Y carriage 14 back and forth in the Y direction, but the yawing error becomes large when the Y carriage 14 is moved back and forth in the Y direction.

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

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

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

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

Further, in the three-dimensional coordinate measuring device 300 of Comparative Example 1, although two air pads 302T are arranged along the Y direction on the right end side of the upper surface 10T of the surface plate 10, the present embodiment shown in FIG. 7 described above. Unlike the three-dimensional coordinate measuring device 1 of the above, the air pad is not arranged on the lower surface side of the surface plate 10. That is, since the three-dimensional coordinate measuring device 300 of Comparative Example 1 is not provided with the surface plate 10 or the air pad facing the lower surface of the Y guide (not shown) provided on the surface plate 10, the drive side The portion that determines the position of the right Y carriage 16 in the vertical direction (Z-axis direction) is only the upper surface of the surface plate 10. Therefore, in the three-dimensional coordinate measuring device 300 of Comparative Example 1, a pitching error becomes a problem in addition to the yawing error.

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

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

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

In 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 device 1 of the present embodiment, and the upper and lower surfaces thereof are sandwiched. It is necessary to provide a drive unit 80 (see FIG. 7) between them. As a result, when the Y carriage 14 (right Y carriage 16) is moved in the Y direction, both the upper and lower surfaces of the surface plate 10 become the support points of the right Y carriage 16, and the positions sandwiched between these two support points. Since the drive unit 80 is located at the center, pitching errors are less likely to occur even when the Y carriage 14 is accelerating and decelerating. In order to suppress pitching errors during acceleration and deceleration, the drive unit 80 should 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 position of the air pad 62E and the air pad 62F. Is preferable.

In the three-dimensional coordinate measuring device 300 of Comparative Example 1, the air pad is not provided on the lower surface of the platen 10, and the right Y carriage 16 has only one support point in the vertical direction. In addition to the pitching error, swinging of the right Y carriage 16 around the Y axis, that is, a rolling error may occur. Even when such a rolling error occurs, the sliding resistance cannot be balanced on the left and right as in the case where the pitching error occurs, which may lead to deterioration of the yawing error.

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

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

FIG. 25 is a front view (frontal schematic view) showing the appearance of the three-dimensional coordinate measuring device 400 of Comparative Example 2 disclosed in Japanese Patent Application Laid-Open No. 64-035310 or Japanese Patent Application Laid-Open No. 62-235502. .. In the three-dimensional coordinate measuring device 400 of Comparative Example 2, those having the same function or configuration as the three-dimensional coordinate measuring device 1 of the present embodiment are designated by the same reference numerals and the description thereof will be omitted.

As shown in FIG. 25, in the three-dimensional coordinate measuring device 400 of Comparative Example 2, the support portion 50 supporting the right Y carriage 16 on the drive side (the drive unit is not shown) includes an air pad 402R, an air pad 402T, and an air pad 402L. It is supported by the Y guide 42 (surface plate 10) via the air pad 402B and the air pad 402B. The air pad 402R is arranged on the right side surface of the Y guide 42 of the surface plate 10, the air pad 402T is arranged on the upper surface side of the Y guide 42, the air pad 402L is arranged on the left side surface of the Y guide 42, and the air pad 402B is arranged on the left side surface of the Y guide 42. It is arranged on the bottom surface side.

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

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

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

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

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

FIG. 26 is a front view (schematic front view) showing the appearance of the three-dimensional coordinate measuring device 500 of Comparative Example 3. In the three-dimensional coordinate measuring device 500 of Comparative Example 3, those having the same function and configuration as the three-dimensional coordinate measuring device 1 of the present embodiment are designated by the same reference numerals and the description thereof will be omitted.

As shown in FIG. 26, the support portion 50 that supports the right Y carriage 16 on the drive side driven in the Y direction by the drive unit 501 is a Y guide 42 (surface plate) via an air pad 502R, an air pad 502T, and an air pad 502L. It is supported by 10). The air pad 502R is arranged on the right side surface of the Y guide 42 of the surface plate 10, the air pad 502T is arranged on the upper surface side of the Y guide 42, and the air pad 502L is arranged on the left side surface of the Y guide 42. The air pads 502R, 502T, and 502L are provided at two positions along the Y direction, respectively.

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

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

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

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

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

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

Therefore, as in the three-dimensional coordinate measuring device 1 of the present embodiment, the scale 112 is provided on the left side surface 40L (see FIG. 3) of the groove 40, and the measurement object is arranged on the upper surface 10T of the surface plate 10. It is preferable to shorten the distance from the scale 112 to the scale 112. That is, it is preferable that 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 (driving unit 80) are arranged in this order. In this way, by providing the scale 112 on the drive side (right Y carriage 16 side) and near the measurement area, the error can be minimized even if there is a yawing error. When the scale is provided on the left side surface 40L perpendicular to the upper surface 10T, even if dust or dirt falls from the upper part (upper side) of the surface plate 10, it does not get on the scale 112 and is dusty. The reading of the scale 112 does not malfunction due to dust or dust.

FIG. 27 is a front view (schematic front view) showing the appearance of the three-dimensional coordinate measuring device 1 of the present embodiment. FIG. 28 is a cross-sectional view (schematic cross-sectional view) along the line XXVIII-XXVIII in FIG. 27. FIG. 29 is a top view showing the upper surface 10T of the surface plate 10, and is a view showing the arrangement of each air pad provided on the Y carriage 14 and the drive unit 80. The rectangular frame shown by the alternate long and short dash line in FIG. 28 indicates the position of the drive unit 80.

As shown in FIGS. 27 to 29, the three-dimensional coordinate measuring device 1 of the present embodiment has the following differences 1 to 4 with respect to the comparative examples 1 to 3.

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

The difference 2 is that in the three-dimensional coordinate measuring device 1 of the present embodiment, since the rotational moment due to the driving of the driving unit 80 is applied to the Y carriage 14, the portion driven by the driving unit 80 is moved up and down so as to sandwich the driving unit 80. Air pads are placed on the left, right, front and back. This makes it possible to reduce pitching errors and rolling errors that lead to deterioration of yawing errors.

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

Further, as shown in FIG. 29, the driven air pad 70 is located substantially opposite to the surface plate 10 with respect to the drive unit 80, and is driven by the line LX connecting the driven air pad 70 and the drive unit 80. The line LY connecting the two pairs of air pads existing before and after the portion 80 may be perpendicular to the line LY. From another point of view, it is preferable that the drive unit 80 is provided at the intermediate point between the two pairs of air pads on the drive side, and the driven air pad 70 is also provided at the intermediate point between the two pairs of air pads on the drive side.

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

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

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

FIG. 30 is a front schematic view of the three-dimensional coordinate measuring device 1A of another embodiment including the Y guide 42Z different from the above embodiment. As shown in FIG. 30, the right end portion (the end portion facing the right Y carriage 16) in the figure of the upper surface 10T of the surface plate 10 is a convex portion provided in a convex shape in the Z direction and has a Y axis. A convex portion extending in the direction is formed. Then, the convex portion forms a Y guide 42Z that movably supports the right Y carriage 16 in the Y-axis direction. The three-dimensional coordinate measuring device 1A has basically the same configuration as the three-dimensional coordinate measuring device 1 of the above embodiment except that the Y guide 42Z is provided.

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

1 ... Three-dimensional coordinate measuring device, 10 ... Surface plate, 10B, 20B, 42B, 202B ... Bottom surface, 10R, 24R, 40R, 42R, 250R ... Right side surface, 10T, 20T, 42T, 202T ... Top surface, 12 ... Carriage, 14 ... Y carriage, 16 ... Right Y carriage, 18 ... Left Y carriage, 20 ... X guide, 20E, 24E, 202E, 250E ... Rear, 20F, 24F, 202F, 250F ... Front, 22 ... Z column, 24 ... Z Carriage, 24L, 40L, 42L, 250L ... Left side, 26 ... Measuring probe, 28 ... Stylus, 40 ... Groove, 40B ... Bottom, 42 ... Y guide, 50, 200 ... Support, 52 ... Base end, 54 ... Right side, 56 ... Left side, 58 ... Tip, 58A ... Support plate, 62E, 62F, 64E, 64F, 66E, 66F, 68E, 68F, 70, 210, 212, 214, 216, 260, 262, 264, 266 ... Air pad, 80, 220, 270 ... Drive unit, 82, 222, 272 ... Motor, 84, 224, 274 ... Roller, 110 ... Linear encoder, 112 ... Scale, 114 ... Optical sensor, 130L ... Left rail, 130R ... Right rail, 132L, 132R ... Guide groove, 134, 134E, 134F ... Bellows cover, 150, 152 ... Insulation member, 202 ... X guide insertion hole, 250 ... Z carriage insertion hole

Claims (1)

A surface plate that has upper and lower surfaces and side surfaces and on which an object to be measured 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 is supported by the surface plate by two support members.
The two strut members include a first strut member having a drive mechanism for driving the Y carriage in the Y-axis direction, and a second strut member that follows and moves the first strut member.
The surface plate has two side surfaces perpendicular to the upper surface of the surface plate on the first support column member side, and the side surface of the surface plate and the side surface of a groove formed on the surface plate along the Y-axis direction. A guide having two side surfaces and having a guide extending in the Y-axis direction.
The first strut member is slidably supported on the upper surface of the guide, and the first strut member has two pairs of upper and lower side surface support members that sandwich the guide from the top, bottom, left, and right.
A three-dimensional coordinate measuring device in which the drive mechanism includes a roller and a motor for rotating the roller.

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