JPH0363513A - Measuring instrument - Google Patents

Abstract

PURPOSE:To measure the straightness, etc., of a body to be measured with high accuracy by absorbing the oscillatory rotation of a ball screw shaft by displacing a joint piece and a displaced member relatively. CONSTITUTION:When the straightness of the body to be measured is measured by providing, for example, a joint piece 76, the displaced member 80, i.e. a displacement plate 66, and a lid body 79 as an eccentric motion absorbing means 60, the oscillatory rotation of the ball screw shaft 27 which exerts adverse influence can be absorbed by the relative displacement between the joint piece 76 and displaced member 80. Therefore, the majority of the oscillatory rotation is absorbed by the eccentric motion absorbing means 60, so only the linear motion of the ball screw shaft 27 is securely transmitted to a detector and the probe of the detector is displaced almost linearly. Consequently, the straightness of the body W to be measured is accurately measured.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a measuring machine such as a straightness measuring machine, a three-dimensional measuring machine, a surface profile measuring machine, etc. The present invention relates to an improvement in a straight guide mechanism for straightly guiding a slider supported by a slider.

[Background technology]

2. Description of the Related Art Various surface profile measuring machines are widely used as devices for measuring roundness, straightness, parallelism, etc. of objects to be measured. This type of surface profile measuring machine includes, for example, a base on which the object to be measured is placed, a column that is erected at one end of this base, and a column that surrounds this column and extends above and below it. Some devices include a slider that can be slid in any direction, and a detector that is attached to the slider and can move forward and backward with respect to the object to be measured.

For example, when using such a surface profile measuring machine to measure straightness, that is, the degree to which the surface profile of a straight part of the workpiece approximates to a straight line, first, a lever-type dial gauge is used. (test indicator) or the like is brought into contact with a straight line part of the object to be measured. When the slider attached to the support column is displaced in the direction along the straight line, for example, in the vertical direction while in this contact state, the detector is also displaced accordingly. At this time, the probe of the detector is displaced while remaining in contact with the straight part of the object to be measured, so it swings following the unevenness of the straight part.
By detecting the degree of this oscillation, the straightness of the object to be measured is measured.

By the way, in boat fishing, a ball screw shaft is often used as a means for vertically displacing the slider, and the slider is screwed onto this ball screw shaft. Therefore, the slider is configured to be displaced in the vertical direction by rotating the ball screw shaft.

[Problem to be solved by the invention]

However, the ball screw shaft, although slightly
It has eccentricity and bending. Therefore, when the ball screw shaft is rotated, the slider screwed onto the ball screw shaft will
Eccentric movement and vibration occur in the outward radial direction, causing a so-called whirling phenomenon. For this reason, the detector, which is integrally supported with the slider screwed onto the ball screw shaft, also moves eccentrically, making it difficult to accurately measure the straightness of the object to be measured. This exposes the shortcomings.

Therefore, by making the part that is screwed onto the ball screw shaft independent of the slider by using a ball nut, and by stretching a wire parallel to the ball screw shaft between the ball nut and the slider, this whirling can be absorbed by the wire. However, a device has been proposed that can measure straightness with high accuracy.

However, in this case, as the diameter of the wire increases, the amount of displacement of the wire itself decreases, and whirling cannot be effectively absorbed. For this reason, the diameter of the wire is reduced to absorb whirling.

Therefore, a surface profile measuring machine that adopts this type of mechanism can only be used when the weight of the slider is relatively light.If this i-structure is adopted for a surface profile measuring machine that has a heavy slider, the strength of the wire will increase. There are concerns about a shortage.

In addition, the feed screw shaft is held between a pair of wires from both sides, and the tips of these wires are pulled by a spring to engage the thread grooves of both wires on the feed screw shaft, thereby absorbing eccentric movement (actually used in practical applications). (Japanese Publication No. 58-32411), and one in which a pair of rollers are supported on swingable arms instead of wires, and these arms are pulled by a cylinder to engage each roller with the thread groove of the feed screw shaft ( Furthermore, a screwless drive shaft is used instead of the feed screw shaft, and a roller inclined in the feeding direction is engaged with this drive shaft (Utility Model Application No. 62-18).
6011, Japanese Utility Model Application Laid-open No. 62-189608), etc.

However, although these pose no problem in horizontal direction feeding, wires or rollers may lack strength for vertical feeding, as in the prior art example.

An object of the present invention is to provide a measuring instrument that does not affect a slider due to whirling (eccentric motion) due to bending of a ball screw shaft, etc., and that is equipped with an eccentric motion absorbing means that can be applied to a heavy slider. is to provide.

[Means for Solving the Problems] The present invention provides a ball nut screwed onto a ball screw shaft;
An eccentric motion absorbing means is interposed between the slider and the slider that is slidably supported by the column, and the eccentric motion absorbing means is connected to a shaft that surrounds the ball screw shaft and has one end fixed to the slider side or the ball nand side. 1. The second joint piece is interposed between the other ends of the first and second joint pieces, and the first and second joint pieces are arranged in the radial direction perpendicular to each other of the ball screw shaft. This measuring instrument is characterized in that it is configured to include a displacement member that is slidable and supported in an axially immovable manner.

Further, in the measuring device according to the present invention, each of the joint pieces has a bottle protruding from each other in a direction orthogonal to each other, and the bottle of these joint pieces is slidable in the axial direction of the bottle. In addition, the displacement member may be supported by a displacement plate defined with an orthogonal groove that guides the displacement plate in a direction perpendicular to the axis so as not to be movable, and a lid placed on the displacement plate.

[Function] In the present invention, the whirling of the ball screw shaft caused by rotating the ball screw shaft can be controlled by, for example,
By providing an eccentric motion absorbing means that absorbs the eccentric motion by relatively displacing the plurality of bins of the pair of joint pieces and the displacement member, it can be adopted even in a heavy slider. The whirling is absorbed by a displacement member that connects the pair of first and second joint pieces so as to be slidable in radial directions perpendicular to each other and not displaceable in the axial direction of the ball screw shaft, There is nothing to tell the slider. Therefore, the slider can be displaced substantially linearly, and the detector attached to the slider can also be displaced substantially linearly, making it possible to measure the straightness, etc. of the object to be measured with high precision. becomes.

〔Example〕

Next, a preferred embodiment in which the measuring device according to the present invention is applied to a surface shape measuring device capable of measuring straightness, roundness, parallelism, etc. will be listed and explained in detail with reference to the attached drawings. do.

In FIG. 1, reference numeral 10 indicates a surface profile measuring machine according to this embodiment, and this surface profile measuring machine 10 is placed on a support stand 11 placed on the floor.

The surface profile measuring machine 10 includes measuring means 2 for performing various measurements.
0, and an output means 50 for displaying the measurement results of the measuring means 20 on paper or electrically.

The measuring means 20 includes a base 21, on which is a rotary table 22 on which a cylindrical object to be measured W is placed.
is rotatably provided in the direction of the arrow via an air bearing (not shown). The rotary table 22 has a centripetal device (not shown) in order to support the object W to be measured at the center of the rotary table 22. Further, a counter section 23 is provided near the rotary table 22 to display the rotation angle, rotation speed, etc. of the rotary table 22.

A support plate 24 is fixed to the base 21 on the side of the rotary table 22, and a column 25 having a substantially inverted letter shape is erected at one end of the support plate 24 on the back side. A motor 26 rotatable in the direction of arrow A is attached to the upper surface 25A of this column 25, and an output shaft (not shown) of this motor 26 is connected between the column 25 and the support Fi, 24. A ball screw shaft 27, which is rotatably supported by the column 25 and arranged substantially parallel to the column 25, is connected thereto.

A rectangular frame-shaped slider 2B surrounding the column 25 is mounted on the column 25 so as to be slidable in the two directions of the arrows, that is, in the up and down directions. Eccentric motion absorbing means 60, which will be described in detail later, is interposed between the slider 28 and the ball nut 29 screwed onto the ball screw shaft 27.

An X-axis drive device 31 is attached to the front surface of the slider 28, and this X-axis drive device 31 is provided with a support shaft 32 that can be freely displaced in the direction of arrow X, that is, in one horizontal direction. . This support shaft 32 is extended in the X direction and Xll1! An arm 33 that is driven in the axial direction by the I drive device 31, a connecting arm 34 that extends perpendicularly to this arm 33, and a connecting arm 34 that is connected to the tip of this connecting arm 34 and that extends in the direction of extension of the arm 33 (X direction). ) and a distal end arm 35 extending to

A lever type dial gauge (test indicator) type detector 41 is detachably attached to the tip arm 35, and this detector 41 is provided with a measuring point 42 that can swing in the direction of arrow B. .

At the other end of the support plate 24, on the near side, there are provided an operation section 45 in which a plurality of switches are arranged, and a joystick 48. When the joystick 48 is displaced in the direction of the arrow X, the support shaft 32 is moved. The support shaft 32 is configured to move in the direction of arrow X when the joystick 48 is displaced in the direction of arrow X and in the direction of arrow Y, respectively.

On the other hand, the output means 50 includes an operation section 51 in which a plurality of switches are arranged, a display section 55 indicating the amount of displacement of the probe 42 provided on the detector 41, and a perfect circle of the object W to be measured. The output unit 58 records the degree, straightness, etc. on paper.

Here, the eccentric motion absorbing means 60 provided between the slider 28 and the ball nut 29 will be explained with reference to FIGS. 2 to 4.

The eccentric motion absorbing means 60 includes an abbreviated mounting plate 62 fixed to the slider 28 by four screws 61, and a ball screw shaft 27 is attached to the bottom 63 of the mounting plate 62.
A hole 64 having a sufficiently larger diameter is bored. Further, two screw holes 65A and 65B are provided in the bottom portion 63 so as to penetrate into the hole portion 64 from the outside.

On the bottom 63 of the mounting plate 62, there is a displacement plate 66 that can be moved in any direction! ! It is placed. A hole 67 having approximately the same diameter as the hole 64 is bored in the center of the displacement plate 66, and grooves 68A to 68D are formed in a cross shape from the outer periphery of the hole 67 to the outer surface of the displacement plate 66. Furthermore, a total of four screw holes 69 are screwed into each corner of the displacement plate 66.

The hole 64 and the hole 67 are provided with the ball screw shaft 27.
The hole 7 is sufficient to pass through, i.e., surround, the hole 7.
A cylindrical first joint piece 71 having a diameter of 1A is loosely fitted into the hole 6 of this joint piece 71.
The lower end portion which is the engaging portion to the screw hole 6 of the bottom portion 63
Set screws 72A, 7 screwed into 5A, 65B, respectively
2B to the mounting plate 62. Furthermore, protrusions 73A and 73B are integrally provided on the upper surface of the first joint piece 71, and these text parts 73A and 73B
Cylindrical bins 74A and 74B are provided on the same straight line to protrude outward in the single shape direction.

These cylindrical bottles 74A, 74B are engaged with grooves 68A, 68B of the displacement plate 66, respectively.

On the other hand, cylindrical bottles 75A and 75B are engaged with the grooves 68C and 68D of the displacement plate 66. A protrusion 77 of the second serrated piece 76 that can be turned and has a hole 76A.
A and 77B are provided respectively. And each of the bins 74A.

To prevent removal of 74B, 75A, and 75B, the displacement plate 66 is covered with a lid 79 in which a hole 7B having a diameter larger than the diameter A of the second joint piece 76 is bored. . This lid body 79 has four screws 82 (only one is shown in FIG. 4) inserted into holes 81 formed at its four corners.
is screwed into the screw hole 69 of the displacement Fi66,
It is fixed to the displacement plate 66.

At this time, the depth of the grooves 68A to 68D is exactly the same as that of the cylindrical bottle 7.
4A, 74B and 75A, 75B diameters,
Each of the cylindrical bottles 74A, 74B and 75A, 75B is held between a displacement plate 66 and seven lids so as to be movable in the axial direction of the bottle without play. put it here,
A displacement member 80 is constituted by the displacement Fj, 66 and the lid body 79.

Therefore, the first and second pair of ditint pieces 71.7
6 surrounds the ball screw shaft 27 with the holes 71A and 76A, and are perpendicular to each other by the action of the cylindrical pins 74A, 74B and 75A, 75B held between the grooves 68A to 68D of the displacement plate 66 and the lid 79. The ball screw shaft 27 is slidable in the radial direction, and the ball screw shaft 2
7 are connected so as not to be displaceable in the axial direction. Note that the first and second joint pieces 71.7 are connected by the displacement member 80 so as not to be displaceable in the axial direction of the ball screw shaft 27, respectively.
6 is both joint pieces 71, 76 and displacement member 80
Of course, the entire eccentric movement absorbing means 60 is movable in the axial direction of the ball screw shaft 27.

A support plate 83 is placed R on the lid 79, and the support plate 83 has a hole having approximately the same diameter as the hole 78 and slightly larger than the outer diameter of the second joint piece 76. hole 84;
Four screw holes 85 are provided at the four corners, and screw holes 86A are provided on the side surfaces thereof to communicate with the holes 84 from the outside.
86B is screwed. These screw holes 86A, 86
The upper end of the second joint piece 76 is fixed to the support plate 83 by screwing the setscrews 87A and 87B into the joint pieces B, respectively.

Furthermore, on this support plate 83, a mounting base 88 is installed. The mounting base 88 is fixed to the support plate 83 by penetrating the holes 89 provided at the four corners of the mounting base 88 and screwing the four screws 91 into the screw holes 85 of the support plate 83. There is. Approximately in the center of this mounting base 88, the ball nut 29
The lower end of the ball nut 29 is fixed, and a screw thread 29A is screwed into the inner periphery of the ball nut 29.
A ball screw shaft 27 is screwed through B (see FIG. 3).

The surface profile measuring device 10 according to this embodiment is basically configured as described above, and its operation will be explained next.

The surface profile measuring machine IO can measure straightness, roundness, parallelism, etc., but here, the case of measuring straightness will be explained.

First, the object W to be measured is placed on the rotary table 22, and then the joystick 48 is displaced in the directions of the arrows X and Y to bring the probe 42 of the detector 41 into contact with the upper surface of the object W ( (as shown by the two-dot chain line in the figure), the joystick 48 is returned to the neutral position (the position in the figure).

Next, when the joystick 48 is displaced in the direction of arrow Y, the ball screw shaft 27 rotates in the forward direction of arrow A under the rotational action of the motor 26, so that the ball nut 29 screwed onto the ball screw shaft 27 is lowered in the Z1 direction, and the slider 2 is further displaced downward in the Z direction via the eccentric movement absorbing means 60. Therefore, the probe 42 of the detector 41 supported by the slider 28 via the X-axis drive device 31 and the support shaft 32 is displaced downward in the direction of arrow Z1 while coming into contact with the side surface of the object W to be measured. In this way, when the measuring element 42 reaches the lower surface of the object W to be measured, the displacement of the measuring element 42 is stopped by returning the measuring element 42 to the neutral position.

At this time, the measuring stylus 42 is displaced along the unevenness of the outer circumferential surface of the object W to be measured, so the amount of displacement is detected as the straightness of the circumferential surface of the object W to be measured and is inputted to the output means 50. The data is displayed on the display unit 55 and printed out on the output unit 58.

By the way, when the ball screw shaft 27 drives the slider 28 in the direction of the arrow Z, if the ball screw shaft 27 is curved or eccentric with respect to the rotation axis (not shown) of the motor 26, The eccentric movement that occurs in the outward radial direction during rotation, that is, the whirling, is indicated by the arrow X,
This will occur in the Y and composite directions.

In this case, when the ball screw shaft 27 is displaced in the direction of the arrow χ, the ball nut 29 screwed thereon is also displaced, and the second joint piece 76 fixed to the support plate 83 is also displaced in the direction of the arrow X. become. However, this displacement occurs when the cylindrical bins 75A, 75B move to the grooves 68C, 68 of the displacement plate 66.
It is absorbed by sliding D (see the two-dot chain line in FIG. 2).

Furthermore, when the ball screw shaft 27 is displaced in the direction of the arrow Y, the ball nut 29 and the second joint piece 76 are also displaced in the direction of the arrow Y, as described above, but this displacement is caused by the cylindrical pins 75A and 75B. It is absorbed by displacing the displacement plate 66 in the direction of arrow Y (see the two-dot chain line in the figure). In other words, the grooves 68A, 68B are fixed to the mounting plate 62.
.

It is absorbed by sliding 74B in the direction of arrow Y.

Furthermore, the whirling that occurs in the combined direction of the arrows X and Y is absorbed by the relative displacement of the second joint piece 76, displacement plate 66, and lid body 79 in accordance with each component in the χ and Y directions. . Therefore, whirling that occurs in any direction from arrow X to Y direction is instantly absorbed. As a result, the detector 41 is displaced linearly almost accurately regardless of the bending or eccentricity of the ball screw shaft 27, and the straightness of the object W to be measured can be precisely measured by the probe 42 of the detector 41.

According to this embodiment as described above, there are the following effects.

That is, as the eccentric motion absorbing means 60, in particular, the second joint piece 76 and the displacement member 80, that is, the displacement plate 6
6 and a lid body 79, the second joint piece 76 and the displacement member 8 prevent the whirling of the ball screw shaft 27, which has an adverse effect, when measuring the straightness of the object W to be measured.
It can be absorbed by the relative displacement with respect to 0. Therefore, since most of the whirling is absorbed by the eccentric motion absorbing means 60, only the linear motion of the ball screw shaft 27 is detected by the detector 41.
As a result, the probe 42 of the detector 41 can be displaced substantially linearly.

Incidentally, even if the detector 41 is displaced by 200 degrees in the direction of arrow Z, it is possible to perform highly accurate straightness measurement with a measurement error of 0.2 μm.

In addition, the eccentric motion absorbing means 60 includes a displacement plate 66 which is a flat plate with grooves, and first and second joint pieces 71.7.
6 is made up of a cylindrical body with pins protruding from it, and the other components are also made of members with simple structures such as flat plates, so they can be provided at low cost.

Although the present invention has been described above with reference to preferred embodiments, the present invention is not limited to these embodiments, and various improvements and changes in design can be made without departing from the gist of the present invention. Of course.

For example, although the grooves 68A to 68D are provided on one surface of the displacement plate 66, other grooves may be provided on the other surface, and further, grooves may be provided on both surfaces separately.

In addition, although the grooves 68A to 68D are square grooves, they may also be round grooves, triangular grooves, etc., and their shapes are not limited.

Furthermore, first and second joint pieces 71. There are two cylindrical bottles 74A and 74B in each case.

75A and 15B were provided, but these cylindrical bottles 74A,
74B, 75A, and 75B may be one or three or more protruding parallel to each other, and the number thereof is not limited.

Also, this cylindrical bottle 74A.

The shapes of 74B, 75A, and 75B can also be made into prismatic shapes. Furthermore, bins 74A, 74B, 75A.

75B, grooves are provided along the circumferential ring direction, and protrusions that engage with these grooves are provided on the displacement plate 66, and the grooves and the protrusions are combined so as to be slidable in the axial direction. good.

In addition, the cylindrical bottles 74A, 74B and 75A, 75B are
The displacement member 8 is not necessarily limited to the one provided on the first and second joint pieces 7176, as shown in FIG.
It may be provided on the 0 side. That is, in FIG. 5, the displacement member 80 is composed of one disc-shaped member 95, and this disc-shaped member 95 has two protrusions 95A on each of its upper and lower surfaces;
95B, 95C, and 95D are provided protrudingly, and these two protrusions 95A, 95B and 95C, 95D are 90 degrees apart from each other.
They are set at different degrees. These protrusions 95A, 95
B, 95C, and 95D have cylindrical bottles 74A and 7, respectively.
4B, 75A, 75B protrude inward, and these cylindrical bottles 74A, 74B and 75A, 75B are connected to first and second joint bead shafts which are formed into a thicker cylindrical shape than in the previous embodiment. 1. Each 2 formed in the frame 6
The ball screw shaft 27 is supported in the respective holes 96A, 96B, 96G, and 96D so as to be slidable in the radial direction of the ball screw shaft 27 and not displaceable in the axial direction. At this time, the opposing inner end surfaces of the first and second joint pieces 71 and 76 are exactly in contact with the upper and lower end surfaces of the disc-shaped member 95. Also, the first
The outer ends of the second joint pieces 71, 76 are fixed to a mounting plate (not shown) on the slider side and a support Fi (not shown) on the ball nut side, as in the previous embodiment.

In summary, in the eccentric motion absorbing means according to the present invention, a displacement member is interposed between a first shield piece attached to the slider side and a second shield piece attached to the ball napft side. It is sufficient that the first and second joint pieces are supported by the member so as to be able to slide in the radial direction of the ball screw shaft and in directions orthogonal to each other, and to be immovable in the axial direction of the ball screw shaft, First,
The shape, structure, number of component parts, etc. of the second shield piece and the displacement member are not limited.

It goes without saying that the eccentric motion absorbing means 60 can be used not only in the surface profile measuring machine 10 but also in other types of measuring machines that use a ball screw shaft as a feeding means, such as a three-dimensional measuring machine.

Furthermore, the detector 41 is not limited to one having a contact type probe 42 that comes into contact with the object W to be measured. It may also be a measuring device that performs measurements.

〔Effect of the invention〕

According to the present invention as described above, it is possible to provide a measuring device that does not affect the detector even if the ball screw shaft used as the slider feeding means is bent or the like.

[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 perspective view of eccentric motion absorbing means, which is a main part thereof,
The figure is a cross-sectional view of FIG. 2, FIG. 4 is an exploded perspective view of FIG. 2, and FIG. 5 is a perspective view showing essential parts of another embodiment of the present invention. 10... Surface profile measuring machine, 20... Measuring means, 22
...Rotary table, 25...Column, 27...Ball screw shaft, 2nd...Slider, 29...Ball nut, 41...Detector, 42...Measure head, 50...
- Output means, 60... Eccentric motion absorption means, 62...
Mounting plate, 66... Displacement plate, 71... First shield piece, 71A... Hole, 74A, 74B, 75A
, 75B... Cylindrical pin, 76... Second joint piece, 76A... Hole, 79... Lid, 80...
- Displacement member, 95...disc-shaped member.

Claims (2)

[Claims] (1) A slider is slidably supported in a column, and a detector indirectly supported by the column is brought into contact with the object to be measured through the slider, and the object to be measured and the detector are moved by relative displacement. In the measuring machine for measuring the dimensions, shape, etc. of the object to be measured, a ball screw shaft is provided approximately parallel to the column, a ball nut is screwed onto the ball screw shaft, and the ball nut and the slider are screwed together. The eccentric motion absorbing means includes a first joint piece that surrounds the ball screw shaft and has one end fixed to the slider side, and a first joint piece that surrounds the ball screw shaft and has one end fixed to the slider side. is interposed between the second joint piece fixed to the ball nut side, and the other ends of the first and second joint pieces, and one side of the ball screw shaft in the radial direction with respect to the first joint piece. a second joint piece that is slidable in a direction and connected to the ball screw shaft so as not to be displaced in the axial direction of the ball screw shaft; 1. A measuring instrument comprising: a displacement member connected in a manner that cannot be displaced in any direction. (2) In the measuring device according to claim 1, the first
, the second joint pieces each have pins protruding in directions orthogonal to each other, and the pins of these joint pieces are capable of sliding in the axial direction of each pin, and in the direction orthogonal to each axis. A measuring instrument characterized in that it is supported by a displacement member having a displacement plate defined with orthogonal grooves for immovably guiding the respective displacement plates, and a lid body placed on the displacement plate.