JPH0347441B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to a three-dimensional measuring machine, and particularly to an improvement in an automatic feeding device thereof.

[Background Art] In general, an automatic feed device for a measuring machine is composed of a feed screw shaft and a nut member that is screwed onto the feed screw shaft. is provided on the movable member side having the measuring element, and this movable member is moved along a guide member provided on the main body side. In this case, when the movable member and the nut member are integrally connected so that they cannot be relatively displaced, there may be an error in parallelism between the feed screw shaft and the guide member, or the feed screw shaft may have poor pitch, bending, etc. If so, when the feed screw shaft is rotated, fluctuations such as yawing, rolling, and pitting may occur in the moving member or the feed screw shaft, which not only reduces measurement accuracy but also causes weak mechanical strength of each component. There is a risk of damage due to unfavorable force being applied to the product.

For this reason, it is possible to connect the nut member and the movable member via an elastic member, or to connect the nut member and the movable member so that they can move in the radial direction but cannot be displaced in the axial direction, thereby preventing problems caused by rotation of the feed screw shaft. Structures that absorb vibrations are known. In such a structure, it is necessary to prevent the nut member from rotating, but in conventional structures of this kind, the rotation of the nut member is prevented by a moving member.

However, when a moving member is used to prevent the nut member from rotating in this way, the force of rotating the nut member is applied directly to the moving member, and the moving member is displaced by this rotational force, which requires particularly high precision. For three-dimensional measuring machines, the negative effect of this displacement on measurement accuracy is a major problem.

[Object of the Invention] An object of the present invention is to provide an automatic feed device for a three-dimensional measuring machine that does not adversely affect measurement accuracy due to the rotational force of a nut member screwed onto a feed screw shaft.

[Structure of the Invention] In the present invention, when connecting a moving member having a touch signal probe and a nut member screwed onto a feed screw shaft, the feed screw shaft is formed such that the feed screw shaft cannot be relatively displaced in the axial direction and can be easily displaced in the radial direction. A roller is connected to the nut member through a connecting means and is arranged parallel to the feed screw axis and comes into contact with a guide rail attached to the non-moving member side structure, and the nut member is connected to the roller. The structure is configured such that the guide rail, that is, the structure on the non-moving member side directly guides the feed screw shaft in the axial direction through the guide rail, that is, the structure on the non-moving member side, without transmitting the rotational force of the nut member to the moving member. This object is achieved by transmitting only axial feed to the receiving and moving member.

[Example] Hereinafter, an example of the present invention will be described based on the drawings.

In Figures 1 and 2 showing the overall configuration,
A base 10 made of a stone-like member such as natural stone or ceramics is horizontally installed on the installation floor 1 via a plurality of leveling jigs 30. This base 10 is formed into a substantially convex shape, and the base 10 having a convex shape
A first guide member 11 made of a stone-like member similar to the base 10 and forming a guide surface in the Y-axis direction is fixed to the center of the upper surface of 0 with screws. A pair of flat second guide members 12 also made of stone-like members partially connect to the base 10.
It is symmetrically fixed with screws while protruding from the upper surface of the convex part. In this case, the structure for fixing the guide member 11 and the second guide member 12 to the base 10 is such that the first guide This is done by screwing the bolt 16 through the member 11 or the second guide member 12. Furthermore, in this specification, the X-axis direction means the left-right direction in FIG. 2, the Y-axis direction means the direction perpendicular to the plane of the paper in the same figure, and the Z-axis direction means the up-down direction in the same figure, that is, the vertical direction. Then,
These X, Y, and Z axes are three axes that are orthogonal to each other, with the X and Y axes being horizontal axes and the Z axis being a vertical direction.

The leveling jig 30 includes a base 31 having a substantially concave side surface, and a sliding piece 3 that is slidably housed in the base 31 and has an inclined surface on its upper surface.
3, a bolt 34 that is screwed into the upright portion of the base 31 so as to be movable in the vertical direction and allows the sliding piece 33 to advance and retreat along the bottom surface of the base 31; and a contact piece 36 which has an inclined surface that engages with the inclined surface of the sliding piece 33 and is in contact with the lower surface of the base 10, and by turning the bolt 34, both inclined surfaces can be moved. By this action, the height position of the base 10 with respect to the installation floor 1 can be adjusted, and the horizontal position of the base 10 can be determined.

On both sides of the first guide member 11, a plurality of pairs of bend correction means 40, for example, 3 or more pairs, in fact about 16 to 32 pairs, are disposed using inclined surfaces similarly to the leveling jig 30. , the straightness of the parallel guide surfaces 18 for restricting movement in the X-axis direction formed on both sides of the first guide member 11 can be maintained.

A metal table 50 is placed on the base 10.
It is provided so as to be movable in the axial direction. An air bearing 51 facing the parallel guide surface 18 of the first guide member 11 is attached to the lower surface of the table 50 via a bracket 52.
A relatively large air bearing 53 is provided to face the upper guide surface 20 of the parallel guide surfaces 20 for regulating the vertical movement of the second guide member 12 in the Z-axis direction, and a relatively large air bearing 53 is provided below the parallel guide surface 20. Side guide surface 20
The air bearing 54 facing the bracket 5
5, and these air bearings 51, 53, 54 allow the table 50 to be attached to the base 1.
0 with a slight force, movement in the X-axis direction is regulated by the action of the first guide member 11 and the air bearing 51, and the second guide member 12 and the air bearing 53,
54, the movement in the Z-axis direction is adjusted and restricted for each axis, and straight movement can only be made in the Y-axis direction.

Furthermore, a Y-axis direction drive mechanism 60 is provided between the base 10 and the table 50 to drive the table 50 in the Y-axis direction. As shown in FIG. 3, this Y-axis direction drive mechanism 60 includes a motor 62 fixed to the base 10 via a bracket 61,
A feed screw shaft 64 consisting of a ball screw shaft connected to the output shaft of this motor 62;
4 is movably screwed into the bracket 6.
5 and a nut member 66 fixed to the table 50 via a nut member 66, and the table 50 can be driven in the Y-axis direction by driving the motor 62. At this time, the feed screw shaft 64 is disposed within the groove 21 of the first guide member 11, so that the feed screw shaft 64 is located at the middle of the table 50 in the width direction, that is, in the X-axis direction, approximately at the center. There is.

The amount of feed of the table 50 by the motor 62 is determined by a scale 76 provided on the first guide member 11 side and a detection unit 7 provided on the bracket 52 side of the table 50, as shown in FIG.
7, and the zero point position for measuring the origin position of the table 50, that is, the absolute position, is determined by the zero mark 81 provided on the first guide member 11 side and the table 50. It is set by a zero set means 80 consisting of a detection switch 82 provided on the 50 side. Furthermore, the movement range of the table 50 is controlled by a dot 85 provided on the base 10 and a limit switch (not shown) provided on the table 50 side.

In FIG. 2, pillars 90 are fixed to both sides of the base 10, respectively. The structure of fixing the support column 90 to the base 10 is such that a substantially pestle-shaped fastener is inserted into a plurality of holes provided along both sides of the base 10 in the Y-axis direction, and the through-holes are inserted into the holes. This is done with a bolt that is screwed in. These pillars 90 are each made of metal such as iron, and the base 1 is provided between the upper ends of these pillars 90.
A beam 100 as a non-movable body side structure made of a stone-like member similar to 0 is horizontally fixed. This beam 1
Similarly to the fixing structure between the column 90 and the base 10, the fixing structure between the column 90 and the column 90 is made of a hole provided on the beam 100 side made of natural stone or the like, and a metal material inserted into this hole. The bolt is inserted into a screw hole of the tightening fitting and inserted through a through-hole provided on the beam 100 side.

A slider 110 is supported on the beam 100 so as to be movable in the X-axis direction, and a guide rail 105 for guiding the slider 110 in the X-axis direction and a guide rail 105 for detecting the amount of movement of the slider 110 are provided on the back surface of the beam 100. scales 106 are provided respectively.

At the rear of the beam 100, as shown in FIGS. 4 and 5, an X-axis direction drive mechanism 120 for driving the slider 110 in the X-axis direction is provided. This X-axis direction drive mechanism 120 includes a motor 122 supported on one support 90 via a bracket 121, and a feed screw shaft 124 consisting of a ball screw shaft that is rotationally driven by the motor 122 via a timing belt 123. One end of the feed screw shaft 124 is rotatably supported, and the upper bracket 1 is attached to the bracket 121.
25, a bearing 128 that rotatably supports the other end of the feed screw shaft 124 and is attached to the other support column 90 via a bracket 127, and the feed screw shaft 124. A nut member 129 is screwed together so as to be movable in the axial direction, a connecting plate 130 is fixed to the nut member 129, and a thrust bearing 131 is formed on both sides of the protrusion of the connecting plate 130, and a spherical part is formed at the tip. a bracket 133 having a planar inverted concave shape that supports the feed screw shaft 124 through a push screw 132 so as to be immovable in the axial direction but movable in the radial direction and is further fixed to the slider 110; and the connecting plate 1.
A connecting tool 134 having one end fixed to 30 and having a planar crank shape, and this connecting tool 13
a guide rail 1 rotatably attached to the other end of the beam 100 and provided on the back side of the beam 100;
Nut member 129 is abutted to sandwich 05.
A pair of rollers 13 that allow axial movement of the feed screw shaft 124 with low friction and prevent rotation.
5, a rotating disk 136 attached to the other end of the feed screw shaft 124, and the bracket 1.
27 via a bracket 137 and stops the rotating disk 136 by electromagnetic force.
By rotating the motor 122, the slider 110 can be driven in the X-axis direction. It is designed to be measured by an optical detector 118 (see FIG. 6) provided in the. Furthermore, by supporting the rotation prevention of the nut member 129 not by the slider 110 but by the beam 100 which is a non-moving member side structure, the force in the rotational direction applied to the slider 110 is eliminated, and the This is designed to eliminate the effect on measurement accuracy. Furthermore, the thrust bearing 131 and the push screw 13
2 and the bracket 133 constitute a connecting means.

As shown in FIG. 6, the slider 110 includes a bearing box 11 for guiding in the X-axis direction, which is provided so as to surround the beam 100 and has air bearings 111 facing each square surface of the beam 100.
2, a pair of upper and lower bearing boxes 114 for Z-axis direction guidance, each having an air bearing 113 mounted on the front surface of this X-axis direction guidance bearing box 112 and arranged inside in a rectangular planar shape; A Z-axis structure 180 inserted into the guiding bearing box 114 so as to be movable in the Z-axis direction, and a support frame 11 erected on the X-axis guiding bearing box 112.
5, and a lock provided at the upper end of the support frame 115 to prevent free rotation of the Z-axis drive mechanism 140 and prevent the Z-axis structure 180 from falling. A device 160 is provided.

The Z-axis direction drive mechanism 140 includes a motor 141 supported by the support frame 115, and is rotationally driven by the motor 141 via a timing belt 142, and rotates its upper and lower ends to the upper and lower parts of the support frame 115, respectively. A freely supported feed screw shaft 145 having a relatively large screw pitch of, for example, 4 mm or more;
a nut member 146 axially movably supported by the nut member 146;
The guide rail 147 is rotatably supported by the nut member 146 and is attached to the wall surface (not shown) on the front side in FIG. 6 of the support frame 115. Z the nut member 146 along the guide rail 147
A pair of rollers 148 that are guided in an axially movable manner but not rotatable, a connecting plate 149 fixed to the nut member 146, and a feed screw shaft 145 that is attached to the upper and lower surfaces of the protruding end of this connecting plate 149 so that it cannot be axially moved. A bracket 1 is connected to the Z-axis structure 180 for easy movement in the radial direction and is fixed to the upper end of the Z-axis structure 180.
52, and the Z-axis structure 180 can be driven in the Z-axis direction via the bracket 152 by driving the motor 141. At this time, the influence of bending, eccentricity, etc. of the feed screw shaft 145 is such that the feed screw shaft 145
45 which is immovable in the axial direction but movable in the radial direction, and only the movement of the nut member 146 in the Z-axis direction is transmitted to the Z-axis structure 180.

The Z-axis structure 180 is made of a square tube and includes a hollow housing 181 as a Z-axis member, and has an air balance mechanism 190 inside the housing 181.
and a probe attachment/detachment mechanism 200. This air balance mechanism 190 includes a cylinder 191 that is fixed to a housing 181 and has an open bottom end.
A piston rod 194 is housed in the cylinder 191 and is attached to the support frame 115.
By supplying compressed air between the piston 192 and the upper part of the cylinder 191, the weight of the Z-axis structure 180 is supported by the action of this compressed air. This is intended to reduce the load on the feed screw shaft 145 due to the weight of the Z-axis structure 180. Also,
A Z-axis direction movement detection means consisting of a scale and a detector (not shown) is provided between the housing 181 and the support frame 115 so that the axial movement amount of the Z-axis structure 180 can be detected. It's summery.

The probe attachment/detachment mechanism 200 includes a rotatable Z spindle 220 therein, and a probe holder 250 (see FIGS. 1 and 2) is inserted into the probe attachment hole provided at the lower end of the Z spindle 220 for measurement. A touch signal probe 280 having a probe 281 is attached.

On the table 50, one end side, that is, the first
A probe stocker 290 is provided on the back right side in the figure. This probe stocker 290 includes a holding plate 293 (see FIG. 2) attached to the table 50 at a predetermined distance via a holding stand 291. In FIG. 1, a large number of U-shaped notches 292 are provided that open toward the front left side, and predetermined touch signal probes 280 are inserted into these notches 292.
A probe holder 250 having a probe holder 250 is mounted and supported in a predetermined mounting posture.

Although the reference numeral 310 in FIG. 1 is shown in a simplified manner, it has a display section 311 and peripheral devices such as a printer and a CRT (not shown), and further includes:
Reference numeral 320 represents a table 50, which is a control device that includes a computer system having arithmetic functions, storage functions, etc., and controls the movement of each part according to a predetermined program.
The objects to be measured placed thereon include a bellows cover 26 for dustproofing the Y-axis direction drive mechanism 60, and a side cover 27.

Next, the operation of this embodiment will be explained.

According to a command from the control device 310, the table 5
0 is driven by the Y-axis direction drive mechanism 60, the probe stocker 290 is positioned below the Z spindle 220, and in this state, the slider 110 and the Z-axis structure 180 are moved in the X and Z-axis directions to move the Z
A probe stocker 29 is attached to the lower end of the spindle 220.
A predetermined probe holder 250 on 0 is inserted and fixed. Z spindle 2 of this probe holder 250
Attachment to the probe 20 is performed by a probe attachment/detachment mechanism 200 provided within the Z-axis structure 180. At this time, during the feeding operation of the slider 110 in the X-axis direction, the nut member 129 is guided by the guide rail 105 via the roller 135, and the nut member 129
The rotational force is not transmitted to the slider 110, and a decrease in measurement accuracy is prevented.

Next, when the table 50 is moved backward, the probe holder 250 is removed from the probe stocker 290, and measurement by the touch signal probe 280 becomes possible. In this state, the Z-axis structure 180,
The slider 110 and the table 50 are controlled by the control device 3
The probe 28 of the touch signal probe 280 is moved in the Z, X, and Y axis directions according to commands from the
The shape of the object to be measured 320 is measured by sequentially bringing the control device 3 into contact with the measurement points of the object to be measured 320.
10 on the display section 311 and printed out.

According to this embodiment as described above, the slider 11
X-axis direction drive mechanism 12 that moves 0 in the X-axis direction
0, the nut member 129 screwed onto the feed screw shaft 124 is prevented from rotating by a guide rail 105 provided on the beam 100, which is a fixing part, and a connecting tool 134;
Since the measurement is performed via the roller 135, the measurement accuracy can be improved without deforming the slider 110 in the twisting direction and deteriorating the accuracy, compared to the conventional structure in which the slider 110 itself prevents rotation. . In addition, the nut member 129
The structure for transmitting the movement to the slider 110 includes a connecting plate 130 fixed to a nut member 129, a thrust bearing 131 that is movable in the radial direction of the feed screw shaft 124, and a push screw 132 on this connecting plate 130.
Since the measurement is performed via the connecting plate 130 and the bracket 133, the adverse effects on measurement accuracy due to radial deflection, eccentricity, etc. of the feed screw shaft 124 are avoided.
All of this can be absorbed by the radial movement of the thrust bearing 131 and the thrust bearing 131, and there is no adverse effect on the slider 110. Furthermore, since the air balance mechanism 190 is provided inside the Z-axis structure 180, the drive operation force for the Z-axis structure 180 can be extremely small, and the motor 141 that drives this Z-axis structure 180 can be downsized. Therefore, the slider 110 can be made smaller and lighter. Also,
The influence of the eccentricity of the feed screw shaft 145 of the Z-axis direction drive mechanism 140 also affects the X-axis direction drive mechanism 120.
Similarly, the connecting plate 149 and the thrust bearing 15
This can be absorbed by the interaction with 0, and can prevent adverse effects on measurement accuracy. In addition, by making the table 50 movable, the measuring head 2
By making the movable part having 81 a lightweight part after the slider 110, the deflection due to the weight of the movable part on the measuring element 281 side can be extremely reduced, thereby improving measurement accuracy. In the movable table 50, the feed screw shaft 64 for driving the table 50 is arranged in the middle of the table 50, especially in the center thereof, so compared to a case where the feed screw shaft 64 is arranged on one side, the table 50 is less likely to be bent due to bending of the feed screw shaft 64. Errors at the side edges can be reduced.

The motors 62, 122, 141 as drive sources in the above embodiments are not limited to AC, DC, or pulse motors, but may also be air motors, hydraulic motors, or the like. Further, the nut member 129 in the X-axis direction drive mechanism 120 in the above embodiment is connected to the connecting plate 13.
0, the structure in which the guide rail 105 is supported by the connector 134 and the roller 135 can also be applied to the Y and Z axis direction drive mechanisms 60 and 140.

As described above, according to the present invention, it is possible to provide an automatic feed device for a coordinate measuring machine that is free from adverse effects on measurement accuracy based on the rotational force of the nut member screwed onto the feed screw shaft. .

[Brief explanation of drawings]

FIG. 1 is a perspective view showing the overall configuration of an embodiment of the present invention, FIG. 2 is a front view thereof, FIG. 3 is an enlarged side view of the Y-axis direction drive mechanism, and FIGS. 4 and 5 are X-axis FIG. 6 is an enlarged plan view and partially cut away enlarged front view of the directional drive mechanism, and FIG. 6 is a partially cut away enlarged side view of the slider. 10...base, 50...table, 60...Y
Axial drive mechanism, 62...Motor, 64...Feed screw shaft, 66...Nut member, 105...Guide rail, 120...X-axis direction drive mechanism, 122...
... Motor, 124 ... Feed screw shaft, 129 ... Nut member, 130 ... Connection plate, 131 ... Thrust bearing, 132 ... Push screw, 133 ...
Bracket, 134... Connector, 135... Roller, 140... Z-axis direction drive mechanism, 141... Motor, 145... Feed screw shaft, 146... Nut member, 180... Z-axis structure, 220... ...Z spindle, 280...Tatsuchi signal probe, 281
... Measuring head, 310 ... Control device, 320 ... Measured object.

Claims (1)

[Claims] 1 An automatic feeding device for a three-dimensional measuring machine that automatically feeds a moving member having a touch signal probe to a base, which has a feed screw shaft pivotally supported on a non-moving member side structure and is parallel to the feed screw axis. A guide rail is disposed on the feed screw shaft, and the nut member screwed onto the feed screw shaft and the movable member side structure are connected via a connecting means formed such that the feed screw shaft cannot be relatively displaced in the axial direction and can be easily displaced in the radial direction. Further, the nut member includes a roller that comes into contact with the guide rail to allow movement of the nut member in the axial direction of the feed screw shaft with low friction, and prevents rotation of the nut member with respect to the feed screw shaft. An automatic feeding device for a three-dimensional measuring machine characterized by being integrally provided with.