JPH0259928B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a measuring instrument. Specifically, the present invention relates to a measuring machine that moves a spindle in the axial direction without rotating it, and measures the dimensions, position, etc. of a measured object from the amount of displacement at that time.

2. Description of the Related Art Measuring machines are known in which a spindle is brought into contact with an object to be measured, and the dimensions, position, etc. of the object to be measured are measured from the amount of displacement of the spindle at that time. Such measuring instruments often employ a linear spindle drive structure using a screw feed method that allows the spindle to be moved in the axial direction without rotating it.

The reason for this is that the spindle can be easily moved straight by rotating a thimble or the like, and the self-locking action of the screw can be utilized, resulting in excellent operability. In addition, since the spindle does not rotate, it does not cause wrinkles on the object to be measured when the spindle comes into contact with it, and it also has various advantages such as less wear on the spindle tip. By having.

However, none of the linear spindle drive structures using this type of screw feeding system completely prevents incorrect displacement (runout) in the rotational direction of the spindle when moving the spindle, and even if it is slight, the spindle This causes vibration in the direction of rotation. Therefore, even if the detection means for detecting the amount of displacement of the spindle is constructed with extremely high accuracy, highly accurate measurement cannot necessarily be achieved in many cases.

In particular, in a displacement detector in which a main scale is attached directly or indirectly to the spindle, and an index scale is placed and fixed on the body side at a certain distance from the main scale, no matter how high the accuracy of the main scale or index scale is, Even during machining, if there is runout in the spindle, the distance between the main scale and index scale will change, so highly accurate measurements cannot be expected.

Moreover, in the above-mentioned displacement detector, it is troublesome to arrange the main scale and index scale parallel to each other with a certain distance between them, so a lot of time and effort is required for adjustment. There are drawbacks.

SUMMARY OF THE INVENTION An object of the present invention is to provide a measuring device that can achieve high precision measurement by preventing vibration of the spindle that occurs when moving the spindle, and at the same time can easily adjust a displacement detector that detects the amount of displacement of the spindle. Our goal is to provide the following.

Therefore, in the present invention, the spindle is supported so as to be movable in the axial direction with respect to the main body frame, and a first detection body provided on the spindle and a second detection body disposed opposite thereto with a certain distance apart are provided.
In a measuring machine configured as a displacement detector that includes a sensing body and detects a displacement amount of the spindle from a displacement amount of a first sensing body with respect to a second sensing body, the spindle is moved in the axial direction of the main body frame. A first cylindrical body having a circular cross section and a first slit of a predetermined width is attached to the outer periphery of the first cylindrical body. A second cylindrical body having a circular cross section having two slits is fitted and fixed thereto, and an engaging member that freely engages with the first slit and slidably engages with the second slit is provided. A coil spring is provided that protrudes from the spindle and biases the spindle to rotate so that the engaging member is always in contact with an inner surface of one side of the second slit, and also engages with the engaging member and moves the spindle. The above-mentioned object is attempted to be achieved by adopting a structure in which an outer cylinder having a spiral groove for causing rotation is rotatably provided with respect to the main body frame.

Embodiments of the present invention will be described below based on the drawings.

An embodiment of the present invention is shown in FIG. 1, in which a main body frame 11 has a cavity 16;
6 is closed by a cover 17. Further, the main body frame 11 includes a first cylindrical body 22.
The spindle 23 is supported so as to be movable along its axial direction, and an anvil (not shown) is fixed at a position on the axis of the spindle 23 at a predetermined distance from the tip of the spindle 23.

As shown in FIG. 2, the first cylindrical body 22 is
It is formed into a substantially stepped round shaft shape, and the large diameter portion 22
A threaded portion 22 is attached to the end (step) on the small diameter portion 22B side of A.
C, and a threaded ring 24 is attached to this threaded portion 22C.
(See Figure 1) is screwed into the screw ring 2.
The first cylindrical body 22 is fixed to the main body frame 11 by being pressed into contact with one end surface of the main body frame 11 .

The spindle 2 is attached to the central shaft portion of the first cylindrical body 22.
A holding hole 25 with a perfectly circular cross section that slidably holds the
is passed through the spindle 23 in the axial direction. That is, the first cylindrical body 22 is formed to have a circular cross section. Further, one side surface of the large diameter portion 22A is cut out over a predetermined length along the axial direction to form a window portion 26, and the window portion 26 and the holding hole 25 are communicated with each other. Further, planar mounting portions 27 are formed on both upper and lower sides of the window portion 26 in FIG. 2, respectively.

The small diameter portion 22B is formed to have a relatively thick wall, and holds the spindle 23 in the holding hole 25 sufficiently firmly and stably so as to be able to freely slide.
A loose insertion groove 31 constituting a first slit with a predetermined width is formed on one side of 2B along the axial direction of the first cylindrical body 22 and therefore the axial direction of the spindle 23,
The loose insertion groove 31 is opened at one end of the small diameter portion 22B.

One side surface of the spindle 23, which is slidably held in the holding hole 25 of the first cylindrical body 22, is cut out over a predetermined length along the axial direction, and a flat part 32 is provided as a cutout part. It is being In other words, the flat portion 32 is formed by cutting off one side of the spindle 23 to a predetermined width over a predetermined length. A main scale 33 serving as a first detection body is pasted and fixed on this flat portion 32, and this main scale 33 is configured to be completely housed within the holding hole 25 and move within the holding hole 25 together with the spindle 23. , and this main scale 33
is configured so that it can be exposed to the outer peripheral side of the first cylindrical body 22 from the window portion 26 .

As shown in FIG. 3, on the main scale 33 exposed through the window 26, index scales 41 as a second detection body are arranged facing each other so as to be parallel to each other with a predetermined interval apart. ing. The index scale 41 is attached to one side of a holder 42 having a substantially rectangular frame shape, and this holder 42 is screwed to the flat mounting portion 27 via a mounting screw 43 on the lower side in FIG. 3. .
Further, a protrusion 44 that can come into contact with the flat mounting part 27 is formed on one edge of the upper side of the holder 42 in the drawing, and a mounting piece 4 is formed on the upper end of the protrusion 44.
An adjustment screw 46 is attached to the holder via 5. A compression coil spring 47 is interposed between the adjustment screw 46 and the mounting piece 45, and the biasing force of the compression coil spring 47 presses the protrusion portion 44 against the flat mounting portion 27. By adjusting the adjustment screw 46, the mounting angle of the holder 42 with respect to the flat mounting portion 27, in other words, the index scale 41 with respect to the main scale 33 can be adjusted.
The configuration is such that the relative arrangement of the two can be adjusted.

Inside the holder 42, as shown in FIG.
a light emitting element 48 that irradiates light onto the index scale 41 and the main scale 33 at a predetermined angle;
A light receiving element 49 is attached to receive the light emitted from the light emitting element 48, transmitted through the index scale 41, reflected by the main scale 33, and transmitted again through the index scale 41.
Here, the amount of axial movement of the spindle 23 is converted into an electric signal from the light receiving element 48, the light receiving element 49, the main scale 33 as the first detecting body, and the index scale 41 as the second detecting body, and the displacement is detected. Displacement amount detector 51 that detects the amount
is configured.

A second cylindrical body 52 is fitted into the small diameter portion 22B of the first cylindrical body 22. This second cylindrical body 52 is a thin-walled cylindrical body formed to have approximately the same length as the small diameter portion 22B and made extremely hard by hardening or the like. 23) is formed with a long groove 53 constituting a second slit. This long groove 53
is formed by high-precision grinding to a predetermined width narrower than the loose insertion groove 31, and both ends in the longitudinal direction are closed. In other words, both ends of the second cylindrical body 52 are continuous along the circumferential direction, so that even if a force to widen the long groove 53 acts, the diameter of the second cylindrical body 52 is easily expanded. It is configured in such a way that there is no problem.

On the other hand, the spindle 2 located within the small diameter portion 22B
An engaging member 55 is provided at a predetermined position of 3 in a radial direction, and this engaging member 55 is inserted into the loose insertion groove 31.
After being loosely inserted into the inner part, it is inserted into the long groove 53 with both sides guided by the long groove 53.

As shown in FIG. 4, the engaging member 55 is
It is composed of a pin-shaped insertion part 56 and a head 57,
The insertion portion 56 is adapted to be inserted into a mounting hole 58 formed in the diametrical direction of the spindle 23. Further, the head 57 is formed into a substantially stepped cylindrical shape including a large diameter portion 57A and a small diameter portion 57B formed on the large diameter portion 57A. Both side surfaces of the large diameter portion 57A are cut off into a flat shape along the axial direction of the spindle 23, and a contact flat portion 57C is provided on both side surfaces.
are formed, and the distance between these two contact plane portions 57C formed on both side surfaces (that is, the width of the large diameter portion 57A) is formed to be equal to the diameter of the small diameter portion 57B. Further, a holding recess 5 having a predetermined depth and the same shape as the large diameter portion 57A is provided at the upper end of the mounting hole 58.
9 is formed, and the lower end portion of the large diameter portion 57A is fitted into this holding recess 59 to fit the contact plane portion 5.
7C is in a state exactly parallel to the axial direction of the spindle 23, so that the engaging member 55 can be provided to protrude from the spindle 23. Further, the engagement member 55 can be slidably brought into surface contact with the inner circumferential surface of the long groove 53 at the contact plane portion 57C.

A small stepped portion 23A is provided at the end of the spindle 23 so as to protrude along the axial direction.
1 is formed, and the deepest part of the screw hole portion 61 communicates with the mounting hole 58. A fixing screw shaft 62 of a predetermined length is screwed into the screw hole portion 61, and the insertion portion 56 of the engaging member 55 inserted into the mounting hole 58 is fixed to the spindle 23 by the fixing screw shaft 62. (See Figure 6).

Further, a spring fixing screw 63 is screwed into the screw hole 61. A spring fixing slit 64 having a predetermined depth is formed along the diameter direction on one end side of the spring fixing screw 63. When the spring fixing slit 64 protrudes from the small step portion 23A, the spring fixing screw 63 is closed. The screw hole portion 6
1 and is designed to be screwed into the hole.

Further, on the outer periphery of the small step portion 23A, the first
A torsion coil spring 65 is supported as a rotational biasing means for biasing the spindle 23 against the cylinder 22 to rotate in a fixed direction. One end of the torsion coil spring 65 is bent radially inward of the small step portion 23A, and the other end is bent radially outward of the small step portion 23A, and the inwardly bent end is bent into the spring fixing slit 64. The end portion bent outward is inserted into the long groove 53. In addition, the coil spring 6 is attached to the spring fixing slit 64.
After one end of 5 is inserted, the spring fixing nut 66 is inserted.
is screwed into the spring fixing screw 63 (see Figures 5 and 6), so that one end of the coil spring 65 is held between one side of the spring fixing nut 66 and the end face of the small stepped portion 23A. While being fixed to the spindle 23, the other end is inserted into the long groove 53, so that the spindle 23 is urged to rotate with respect to the second cylindrical body 52 in a direction according to the rotational urging force of the coil spring 65. The engagement member 55 is configured to come into contact with one of the inner circumferential surfaces of the long groove 53 only at one contact plane portion 57C. Here, the long groove 53 and the engaging member 55 constitute a spindle rotation prevention means 71. Note that the biasing force (spring pressure) of the torsion coil spring 65 can be adjusted depending on the rotational position of the spring fixing screw 63 (the inclination state of the slit 64), but the biasing force (spring pressure) of the torsion coil spring 65 can be adjusted by changing the rotational position of the spring fixing screw 63 (the inclination state of the slit 64). A washer may be interposed between the end face and the spring fixing nut 66 to further ensure the fixation of the spring 65 by the nut 66.

An outer cylinder 72 is rotatably supported on the outer periphery of the second cylinder 52, and a relatively small diameter portion 57B of the engagement member 55 is slidably fitted into the inner peripheral surface of the outer cylinder 72. A spiral groove 73 with a large pitch is formed. The helix angle of the spiral groove 73 is preferably 10 to 15 degrees, particularly 13 to 14 degrees, in order to allow the spindle 23 to be fed at high speed and to obtain a self-locking effect.

The inner end of a lid member 75 is screwed into one end of the first cylindrical body 22 (see FIGS. 5 and 6).
5 prevents the outer cylinder 72 from coming off. Further, a cylindrical thimble 76 is rotatably fitted in a part of the outer periphery of the outer cylinder 72. A spring retaining groove 77 is provided at a predetermined position on the outer periphery of the outer cylinder 72 located on the inner periphery side of the thimble 76 over the entire circumferential direction.
A right-handed constant pressure coil spring 78 is wound along the spring holding groove 77 . One end of this constant pressure coil spring 78 is connected to the spring holding groove 7.
7 (6th
(see figure), the other end is not fixed and is free,
Further, the outer periphery of this constant pressure coil spring 78 is arranged so as to be in pressure contact with the inner periphery of the thimble 76 . Due to this pressure contact, a frictional force is generated between the inner circumference of the thimble 76 and the outer circumference of the constant pressure coil spring 78.
When the thimble 76 is rotated, rotation is transmitted to the outer cylinder 72 by this frictional force, and the outer cylinder 72 is rotated. These thimble 76 and the constant pressure coil spring 78 constitute a constant pressure means 79.

Here, the engaging member 55, the outer cylinder 72 having the spiral groove 73, and the constant pressure means 79 constitute a spindle drive mechanism 81.

Next, the assembly method of this embodiment will be briefly explained.

The spindle 23 to which the main scale 33 is attached is inserted into the first cylindrical body 22, and the first cylindrical body 22
is tightened and fixed to the main body frame 11 using a screw ring 24. Next, the holder 42 is attached to the flat attachment portion 27 of the first cylindrical body 22. The mounting direction of this holder 42 is adjusted by adjusting the adjustment screw 46. On the other hand, the spindle 23 is rotated and the rotational direction of the spindle 23 is adjusted so that the main scale is exposed from the window 26 and the mounting hole 58 is arranged in the loose insertion groove 31.

Next, the second cylindrical body 52 is fitted into the small diameter portion 22B of the first cylindrical body 22, the loose insertion groove 31 and the long groove 53 are overlapped, and the engaging member 55 is attached to the spindle 23 in the overlapping state. . Next, spindle 23
When the torsion coil spring 65 is attached to one end, the contact plane portion 57C of the engagement member 55 comes into contact only with one side of the long groove 53.

After that, the second cylinder 52 is rotated around the outer circumference of the first cylinder 22 to adjust the distance between the main scale 33 attached to the spindle 23 and the index scale 41 attached to the first cylinder 22. The second cylinder 52 is adjusted to be in an accurate parallel state, and after the adjustment is completed, the second cylinder 52 is attached to the first cylinder with adhesive or the like.
It is adhesively fixed to the outer periphery of the cylindrical body 22.

After adjusting the arrangement of both scales 33 and 41 in this manner, the small diameter portion 57 of the engagement member 55
While fitting the spiral groove 73 into the outer cylinder 72
is supported on the outer periphery of the second cylindrical body 52, and then the constant pressure means 79 and the lid member 75 are attached to complete the assembly. Note that after bonding the second cylindrical body 52 to the first cylindrical body 22, both scales 33,
When it becomes necessary to finely adjust the arrangement of the index scale 41, the adjustment screw 46 may be adjusted to finely adjust the index scale 41 side relative to the main scale 33 side.

Next, the operation of this embodiment will be explained.

When the thimble is rotated, this rotational force is transmitted to the outer cylinder 72 via the constant pressure coil spring 78, but even after the tip of the spindle 23 comes into contact with an object to be measured (not shown), the spindle 23 is still connected to the object to be measured. When attempting to advance to the side, the constant pressure means 79
Due to this action, the thimble 76 rotates idly with respect to the outer cylinder 72, so that a measurement pressure higher than a certain pressure is not applied to the object to be measured.

When the outer cylinder 72 is rotated by the rotation of the thimble 76, the engaging member 55 engaged with the spiral groove 73 tries to move along the spiral groove 73, but the engaging member 55 is moved toward the main body frame 11 side. Since it is also fitted in the long groove 53 of the second cylinder 52 fixed to the outer cylinder 72, the engagement member 55
will move sequentially in a straight line to the right in FIG. As the engaging member 55 moves, the spindle 23 also moves by the same amount in the same direction, and the displacement amount of the spindle 23 is detected by the displacement detector 51.
The amount of displacement is detected electrically. The linear movement of the spindle 23 accompanying the rotation of the spiral groove 73 is performed quickly (at high speed) because the spiral groove 73 is formed with a large pitch. Further, the dimensions, position, etc. of the object to be measured are measured based on the amount of movement and displacement of the spindle 23.

When moving the spindle 23, the engaging member 5
5 will be guided by the long groove 53, and the engaging member 55 protruding from the spindle 23 will be guided by the long groove 53.
Only one side of the long groove 53 is always in contact with the torsion coil spring 65 as a rotation urging means, and this state of being in contact with only one side continues regardless of the direction in which the spindle 23 moves.
Further, the long groove 53 receives a force in the direction of widening due to the engaging member 55 in contact with the long groove 53, but the long groove 53
In other words, both ends of the second cylindrical body 52 are continuous along the circumferential direction, so even if the second cylindrical body 52 is formed extremely thin, the long groove Due to the force acting on 53, the long groove 53
is not expanded in width, and the diameter of the second cylindrical body 52 is not expanded.

This embodiment has the following effects.

The second cylindrical body 52 is provided on the outer periphery of the first cylindrical body 22, and the long groove 53 provided in the second cylindrical body 52 is configured to linearly guide the spindle 23 via the engagement member 55. After fixing the spindle 23 to the main body frame 11 via the first cylinder 22, the rotation direction of the spindle 23 relative to the main body frame 11 can be adjusted by adjusting the rotation of the second cylinder 52. Therefore, it has become extremely easy to properly orient the main scale 33 with respect to the main body frame 11 (and therefore with respect to the index scale 41) during assembly.

Further, although the second cylinder 52 linearly guides the spindle 23, the spindle 23 is
Since it is not directly held on the first side, the second cylinder 52 can be formed thin. Therefore, even if the long groove 53 formed by high-precision grinding is formed with both ends thereof closed, the length of the long groove 53 can be made sufficiently long. In other words, since the second cylindrical body 52 can be made thin, a sufficient length of the forward and backward stroke of the spindle 23 can be ensured, and the entire device can be made smaller when compared with the same stroke.

Further, since both ends of the long groove 53 can be closed, the engaging member 55 is attached to the long groove 53.
Even if a force acts in the direction of widening the long groove 53 from
For example, unlike the case where one end of the long groove 53 is opened at one end of the second cylindrical body 52, the width of the long groove 53 is not widened. Therefore, spindle 2
3, the spindle 23 does not run out (improper displacement in the rotational direction), and the distance between both scales 33 and 41 is always appropriate.
This has the effect that the amount of displacement of the spindle 23 detected by the displacement amount detector 51 is extremely reliable and highly accurate.

In addition, it is easy to harden only the second cylinder 52 by hardening, etc., and it is possible to achieve both high precision and improvement in wear resistance. 52 as the first cylindrical body 22
By fitting it onto the outer periphery of the first cylinder body 22, even if the first cylinder body 22 itself is formed thick and one end side of the loose insertion groove 31 is opened at one end side of the first cylinder body 22, no problem occurs. do not have. In addition, since the loose insertion groove 31 is formed wider than the long groove 53, the second
Fine adjustment of both scales 33 and 41 by adjusting the rotation of the cylindrical body 52 is easy.

Further, since the head 57 of the engaging member 55 is composed of the large diameter portion 57A and the small diameter portion 57B as described above, the contact plane portion 57C of the large diameter portion 57A is in surface contact with the long groove 53. Therefore, unlike the case of point contact, wear is also prevented from this point. On the other hand, since the small diameter portion 57B having a round cross section is in line contact with the spiral groove 73, the spiral groove 73
The movement of the spindle 23 as the spindle 23 rotates becomes smooth.

Furthermore, the engaging member 55 is configured to be brought into surface contact with only one side of the long groove 53 by a torsion coil spring 65 serving as a rotation urging means.In other words, the clearance between the engaging member 55 and the long groove 53 is reduced. has been resolved. Therefore, the engagement member 55 and the long groove 5
spindle 23 based on the clearance between
There is no risk of incorrect rotation (shaking or rattling) of the scales, and from this point of view as well, the arrangement of both scales 33 and 41 is always appropriate, ensuring high precision measurement. effective. Moreover, the torsion coil spring 65 also serves as a backlash prevention means between the engaging member 55 and the spiral groove 73, and from this point as well, there is an effect that high precision measurement is ensured.

Further, the spindle 23 is provided with a flat part 32, and the main scale 33 is directly attached to the flat part 32, and the spindle 23 and the main scale 33 are directly attached to the flat part 32.
3 and 3, the main scale 3
The structure is extremely simple, as there is no need for a special escape space etc. for the spindle 23 and the main scale 33, and there is no need for any special holding means etc. to keep the spindle 23 and the main scale 33 parallel at all times. Miniaturization becomes possible. Moreover, by integrating the spindle 23 and the main scale 33 as described above, when the spindle 23 moves, the spindle 23 and the main scale 33 are integrated.
No vibration is applied to the main scale 33, and no wobbling occurs in the main scale 33, resulting in an extremely preferable structure in terms of improving measurement accuracy.

In the above description, the displacement detector 51 is an optical detector, the first sensing object is the main scale 33, and the second sensing object is the index scale 4.
1, but the present invention is not limited to this. For example, the displacement detector may be an electrostatic type and the first and second sensing bodies may be electrode bodies, or the displacement detector may be a magnetic type. The first sensing object is a magnetic scale, and the second sensing object is a magnetic scale.
The sensing body may be a magnetic head, etc.

Further, the index scale 41 is connected to the first cylinder 2.
It is not limited to what is attached to the main body frame 11, and may be attached directly to the main body frame 11. However, the first cylindrical body 2
2, assembly and adjustment become easy.

As described above, according to the present invention, it is possible to achieve high precision measurement by preventing vibration in the rotational direction of the spindle (incorrect displacement in the rotational direction) that occurs when moving the spindle, and at the same time, it is possible to achieve high precision measurement. A measuring device that can be easily adjusted can be provided.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view showing one embodiment of the present invention, and FIG.
The figure is an enlarged exploded perspective view showing the structure of the spindle and the first and second cylindrical bodies of the embodiment, FIG. 3 is an enlarged sectional view taken along the - line in FIG. 1, and FIG. 4 is one end of the spindle. FIG. 5 is an enlarged sectional view showing a part of FIG. 1, and FIG. 6 is a sectional view taken along the line -- in FIG. 5. 11... Body frame, 22... First cylindrical body, 2
3...Spindle, 25...Holding hole, 26...Window part, 27...Flat mounting part, 31...Free insertion groove, 3
2...Flat portion as a notch, 33...Main scale as a first detection body, 41...Index scale as a second detection body, 42...Holder, 48...Light emitting element, 49...Light receiving Motoko, 51
... Displacement amount detector, 52 ... Second cylindrical body, 53 ...
Long groove, 55... Engaging member, 57... Head, 57A
...Large diameter portion, 57B...Small diameter portion, 57C...Contact plane portion, 65...Torsion coil spring as rotation urging means, 71...Spindle rotation prevention means, 7
2... Outer cylinder, 73... Spiral groove, 75... Lid member, 76... Thimble, 78... Constant pressure coil spring, 79... Constant pressure means, 81... Spindle drive mechanism.

Claims (1)

[Claims] 1. A spindle is supported so as to be movable in the axial direction with respect to the main body frame, and a first detection body provided on the spindle and a second detection body disposed opposite thereto at a certain distance. In a measuring device comprising a displacement detector that detects the amount of displacement of the spindle based on the amount of displacement of a first sensing object with respect to a second sensing object including a body, the spindle is movable in the axial direction of the main body frame. A first cylindrical body having a circular cross section and a first slit of a predetermined width is attached to the outer periphery of the first cylindrical body. A second cylindrical body having a circular cross section having a slit is fitted and fixed, and
freely engaged with the slit and said second
An engaging member that slidably engages with the slit is protruded from the spindle, and a coil spring biases the spindle to rotate so that the engaging member is always in contact with an inner surface of one side of the second slit. A measuring instrument, further comprising: an outer cylinder rotatably provided with respect to the main body frame and having a spiral groove for engaging with the engaging member and moving the spindle.