JPH0126482B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a displacement detector that detects the amount of displacement of various measuring instruments, sliding parts of machine tools, and other members that move linearly.

In general, many displacement detectors are used to detect physical quantities such as length from the relative movement of two objects, from non-contact types such as photoelectric, electromagnetic, and capacitance types to contact types such as contact types. has been put into practical use. For example, in a photoelectric detector, the main scale and the small index scale facing it must maintain accurate parallelism, clearance, etc. in any of the displacement detectors mentioned above. Also, positional regulation of the members that make up the detector is very important.

Conventionally, when assembling such a displacement detector,
First, objects that move relatively, such as the guide rail and support on the base, the X-axis crossbeam and the X-axis slider, or even the X-axis slider body and the Z-axis spindle, move relative to each other. After adjusting each part so that the two objects move smoothly, the scale and detection part that constitute the displacement detector are attached to this.

In this way, conventionally, when installing a displacement detector on each device, the positioning was adjusted in two stages.
It required a sophisticated part for mounting the displacement detector, and it took time and effort to adjust the clearance between the scale and the detection part, parallelism, etc., and required a high level of skill. In addition, the clearance must be adjusted every time the sliding parts of the moving mechanism for two relatively moving objects wear out, and the curvature of the moving mechanism and the curvature of the scale may change, and furthermore, the curvature of the scale may change. There is also the drawback that readjustment must be made each time the situation arises.

SUMMARY OF THE INVENTION An object of the present invention is to provide a displacement detector that is easy to adjust when incorporated into each device and is easy to maintain thereafter.

In the present invention, a shaft member and an engaging member are provided to be movable relative to each other, and the shaft member is formed such that its axis-perpendicular cross section has a straight line portion and a circular arc portion, and a portion that contacts at the straight line portion. The sliding movement between the shaft member and the engagement member is ensured by the two rollers that contact each other at the arc portion, and further,
A scale is attached to the linear portion of the shaft member along the longitudinal direction of the shaft member, and a detection section is attached to the engagement member facing the scale, whereby the shaft member and the scale can be assembled as parts in advance. In this way, the number of adjustment points is reduced and the above object is achieved.

An embodiment in which the present invention is applied to a coordinate measuring machine will be described below with reference to the drawings.

In the overall structural diagram of FIG. 1, a base 21 consisting of a stone surface plate formed into a substantially rectangular parallelepiped has a plurality of screw holes 22 for attaching the object to be measured on its upper surface, and front and rear end surfaces perpendicular to the longitudinal direction. Each has a handle 23 having an L-shaped cross section. This base 21
Two guide rails 31 and 32, which serve as shaft members constituting a guide section in the Y-axis direction, are attached to both the left and right side surfaces of. These guide rails 31, 3
2 is formed to be longer than the length in the longitudinal direction (Y-axis direction) of the base 21, and is provided below the upper surface of the base 21, parallel to this upper surface, and protruding from the side surface of the base 21. In this case, the fact that the guide rails 31 and 32 are below the top surface of the base 21 means that the top surfaces of the guide rails 31 and 32 are at the same or lower position than the top surface of the base 21. In addition, both guide rails 31 and 32 have both sides of the cylinder cut down in parallel so that the cross-sectional shape perpendicular to the longitudinal direction has a substantially oval shape consisting of an arc portion and a straight portion (see Fig. 2). On the other hand, on the outer surface of the guide rail 31 at the front in FIG. 1, a long scale 33 is attached as will be described in detail later.

On the guide rails 31 and 32 on both sides, prismatic supports 41 and 42 are attached to the guide rails 31 and 32, respectively.
It is supported so as to be movable along the longitudinal direction (Y-axis direction). A horizontal member 43 made of one round bar is installed between the columns 41 and 42 on both sides in order to set the distance between the columns 41 and 42 in the X-axis direction to a predetermined dimension. 41, 42
A slider guide rail 46 consisting of two round bars is connected between the upper ends via connecting parts 44 and 45, respectively.
47 and a slider fine movement rail 48 consisting of one round bar is spanned in a direction perpendicular to the guide rails 31 and 32 and parallel to the upper surface of the base 21, that is, in the X-axis direction. At this time, a flat part is formed along the longitudinal direction on the back surface of the upper slider guide rail 46, and a scale (not shown) is provided on this flat part with the same structure as the scale 33 of the guide rail 31, which will be described later. ing.

A box-shaped slider 49 is attached to the two slider guide rails 46 and 47.
A box-shaped spindle support 51 is supported on the slider 49 so as to be movable in the X-axis direction along the Y-axis, and a box-shaped spindle support 51 is supported on the slider 49 so as to be tiltable about the Y-axis. A spindle 52 as a shaft member is supported by the spindle support 51 so as to be slidable in the direction of its central axis, and a measuring element 53 is attached to the lower end of the spindle 52. At this time, the spindle 52 is set so that it can move exactly in the Z-axis direction (vertical direction) when the inclination of the spindle support 51 is zero, and this allows the slider 49 to move in the X-axis direction and the supports 41 and 42 to move. In conjunction with the movement in the Y-axis direction, the measuring head 53 can be moved arbitrarily in the X-, Y-, and Z-axis directions perpendicular to each other with respect to the base 21 and the object to be measured 54 placed on the base 21. has been done. In addition, these pillars 41, 42, horizontal member 43, connecting parts 44, 45, slider guide rails 46, 47, slider 49, angle measuring means 50,
The spindle support 51 and the spindle 52 constitute a probe support member 40 .

The slider fine movement rail 48 and the slider 49, which are spanned between the upper parts of both the connecting parts 44 and 45, are normally slidable, and the tightening screw 144
The slider 49 is fixed so as not to be slidable by tightening it, and in this fixed state, by turning the adjustment nut 141 screwed onto the fine movement rail 48, the slider 49 is finely moved in the axial direction of the guide rails 46, 47 via the fine movement rail 48. It is made possible.

Note that the reference numeral 84 in FIG. 1 indicates the probe support member 40.
The fine movement feed knob, reference numeral 87, is a knob for operating and releasing the fine movement feed, and the reference numeral 9
0 is a shock absorber provided at both ends of the guide rail 31, and reference numeral 95 is a stopper provided at both ends of the guide rail 32. Further, reference numeral 161 is a reflective scale attached to the spindle 52.

In FIG. 2, an enlarged cross-sectional view of the main part of this embodiment, a plurality of holes 24 as recesses are formed in series in the Y-axis direction on both the left and right side surfaces of the base 21, and inside these holes 24. The small diameter portions 25A of the base end of the support shaft 25 constituting the rail support portion are fixed with an adhesive 26, respectively. At this time, the outer periphery of the small diameter portion 25A is processed with unevenness such as twill knurling to increase adhesive strength. Also,
A small diameter convex portion 25C is integrally formed on the tip side of the support shaft 25 via a step portion 25B, and this convex portion 25C
A V-groove 25D is formed in the middle over the entire circumference.

At positions corresponding to each of the plurality of support shafts 25 protruding from one side of the base 21, the inner surfaces of both guide rails 31 and 32 have recesses 31A that are engaged with the convex portions 25C of the support shafts 25. , 32A are formed, respectively, and two screw holes 31B, 32B penetrating into these recesses 31A, 32A are formed from the arcuate surfaces of the guide rails 31, 32, each having an oval cross section. A fixing screw 34 having a tapered tip is screwed into each of the fixing screws 32B. At this time, the center line of the V-groove 25D and the center axis of the fixing screw 34 are formed to be misaligned, and the direction of this misalignment is the same as that of the fixing screw 34.
The center line of 4 is closer to the protrusion 25C than the center line of the V groove 25D.
As a result, when the tapered end surface of the fixing screw 34 comes into contact with the wall surface of the V-groove 25D, the end surface of the stepped portion 25B of the support shaft 25 aligns with the straight line inside each guide rail 31, 32. crimped to the part,
The mounting position of each rail 31, 32 relative to the support shaft 25 can be regulated. Further, both guide rails 31 and 32 are connected to the base 2 via the support shaft 25.
1, each guide rail 3 is bonded using a positioning jig (not shown).
1 and 32 are fixed parallel to the upper surface of the base 21 with high precision, and in particular, the guide rail 31 has sufficient precision to serve as a positional reference for the measuring machine.

A groove 31C is formed over the entire length on the outer surface of one of the guide rails 31 and 32, and the groove 31C is parallel to the center axis of the rail 31, and its bottom surface is parallel to the center axis of the rail 31. It is finished with high precision by simultaneous polishing so that it is parallel to the outer surface. The scale 33 is pasted in the groove 31C, and the scale 33 is, for example, a reflective scale having vertical graduations on the μm order formed on the surface of a stainless steel plate.

An engagement block 61 as an engagement member is fixed to the lower part of the one pillar 41, and this block 6
One set of roller groups each consisting of three rollers 62, 63, and 64 are provided at both ends of the roller 1 in the longitudinal direction (Y-axis direction). These rollers 62, 63, and 64 are arranged so that the normal direction of their circumferential surfaces is 120 degrees, and a bush 62B that is fitted onto the spindle 62A of the roll 62
The fitting portions of the rollers 63, 64 on the support shafts 63A, 64A of the rollers 63, 64 are respectively eccentric by a predetermined amount with respect to the center line.
The normal position of the guide rail 31 can be adjusted to ensure contact with the guide rail 31. Further, among the rollers 62, 63, 64, the roller 62 is formed relatively wide because it comes into contact with a straight section in the cross section of the rail 31, and the other rollers 63, 6
4 is formed narrow because it comes into contact with the arcuate portion of the rail 31. Furthermore, guide rails 31 and 3
The rollers 62, 63, 64 are 3 in the 120 degree direction.
Since the blocks 61 and 41 are abutted at certain points, the blocks 61, that is, the support columns 41, cannot be moved in the X-axis and Z-axis directions.

As shown in the schematic diagram of FIG. 3, the engagement block 61 is provided with a detection section which together with the scale 33 constitutes Y-direction measuring means for measuring the amount of movement of the probe support member 40 in the Y-axis direction. A measurement unit 70 is provided. This measurement unit 70 has the scale 3 mounted on a transparent plate such as glass.
3, a light emitting element 72 as a light source that emits light onto the surface of the scale 33 through the index scale 71; It is composed of a light receiving element 73 as a light emitter that receives reflected light, and a sine wave-like signal generated in the light receiving element 73 due to a change in the amount of light received due to the brightness and darkness of both scales based on the relative movement of both scales 33 and 71. The amount of movement of the support member 40 in the Y direction can be measured using electric current. At this time, the optical axes of the light emitting element 72 and the light receiving element 73 are arranged in a V-shape, and the light from the light emitting element 72 is directed to the scale 3.
3 to ensure that the light reaches the light receiving element 73.

An engagement block 6 is provided at the bottom of the other support 42.
5 is fixed, and the longitudinal direction (Y
There are two rollers 6 at each end of the axial direction).
One set of roller groups each consisting of 6 and 67 rollers are provided. These rollers 66 and 67 are arranged so that the normal direction of their circumferential surfaces is 180 degrees, and
The fitting portions of the rollers 66, 67 on the spindles 66A, 67A of the rollers 66, 67 are respectively eccentric by a predetermined amount with respect to the spindle center line, so that the normal position of each roller 66, 67 can be adjusted, and the guide rail 32
This ensures reliable contact with the At this time, both rollers 66 and 67 are placed on the rail 3 at the 180 degree position.
2, both rollers 66 and 67, that is, the support column 42, are movable in the axial direction of the support shaft 25 (X-axis direction).

Next, a method of assembling the guide rail and rollers in this embodiment will be explained.

The protrusions 25C of the support shaft 25 serving as rail supports are inserted into the plurality of hole-shaped recesses 31A and 32A provided in the guide rails 31 and 32, respectively, and the screw holes 31B and 32A of the guide rails 31 and 32 are respectively inserted.
32B, and the tip of each screw 34 is engaged with the V groove 25D of each support shaft 25.
As a result, the center axis of the fixing screw 34 and the V groove 25D
The stepped portion 25 of each support shaft 25 due to the deviation from the center of
The end face of B is moved so as to come into contact with the straight parts of the guide rails 31 and 32, and this contact causes the guide rail 3
1, 32 and each support shaft 25 are positioned. At this time, the concave groove 31C of one guide rail 31
The scale 33 is accurately positioned and pasted in advance.

Then, with the adhesive 26 interposed,
Insert the base end small diameter portion 25A of each support shaft 25 into each hole 24 of the base 21, and use a jig (not shown) to make the axis of each guide rail 31, 32 parallel to the upper surface of the base 21. position and wait for the adhesive 26 to harden. At this time, the parallelism between the reference guide rail 31 and the other guide rail 32 is not very important.

After the adhesive 26 hardens, both guide rails 31 and 32
The measuring head support member 40 is assembled to the guide rail 31 side, so first, each roller 62, 63, 64 on the support column 41 side with respect to the guide rail 31 is assembled. each roller 62, 63, 6 so that the contact condition is appropriate.
4 eccentric bush 62B, eccentric shafts 63A, 64A
Adjust using. As a result, the probe support member 40 has been assembled with the guide rail 31 as a reference, and then the other guide rail 32 is assembled.
The contact between the support column 42 and each roller 66, 67 is adjusted in the same manner, and the entire temporary assembly is completed. At this time, since the rollers 66 and 67 of the support column 42 are brought into contact with the guide rail 32 from above and below, they are movable in the axial direction of the rail support shaft 25, and therefore the dimensions are determined in advance by the horizontal member 43. The supporting columns 41 and 42 are supported by both guide rails 31 and 32 while maintaining the sized spacing.

Next, the measurement unit 70 as a detection unit attached to the engagement block 61 as an engagement member is adjusted to be parallel to the scale 33 and to have a predetermined clearance, but the entire unit 70 is not shown in the figure for this adjustment. Normal adjustment means, e.g.
This is done using one or more eccentric shafts or adjustment screws. At this time, the adjustment of the unit 70 may be performed using the straight portion (flat portion) of the guide rail 31 as a reference, and in this way, the flat portion of the guide rail 31 and the index scale 71 of the measuring unit 70 can be adjusted. Adjustment can be easily made by inserting a gauge of a predetermined size between the two.

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

That is, the engagement block 61 and the guide rail 31
1 that comes into contact with the straight part of the guide rail 31
Three rollers 62, 63, including three rollers 62,
64, so it can be installed without shifting the position.
If the scale 33 is attached to the guide rail 31 and the measurement unit 70 is attached to the engagement block 61, there is no need to use complicated mounting hardware, rotation prevention means, etc.
The clearance between the scale 33 and the index scale 71 of the measurement unit 70 can always be kept constant. Moreover, once each support shaft 25 is fixed to the base 21, even if the screws 34 are loosened and the guide scales 31, 32 are replaced, the guide rail 31,
32 can be set at the same position with respect to the base 21, and therefore, if the scale 33 or the like is damaged, it can be easily replaced, and subsequent adjustment is not necessary.
Furthermore, since the engaging surface of the roller 62 to the guide rail 31 and the mounting groove 31C of the scale 33 are precisely machined by precision machining, the scale 3
3 into the concave groove 31C, it is possible to maintain parallelism between the engagement surface of the roller 62 and the index scale 71 and the scale 33, and to prevent the scale 33 from bending in the direction of movement of the engagement block 61.
There is no twisting, and no adjustment is required, which can significantly reduce assembly man-hours. Further, as long as the relationship between the guide rail 31 and the roller 62 is not changed, the engagement block 61 and the guide rail 31 can be maintained parallel to each other.
The clearance between the index scale 71 and the index scale 71 can be changed and adjusted. Furthermore, since the guide rail 31 also serves as a fixing block for the scale 33, it does not require special metal fittings and can be manufactured at low cost.

Furthermore, since the guide rails 31 and 32 are adhesively fixed to the base 21 via the support shaft 25, accurate parallelism of the guide rails 31 and 32 to the upper surface of the base 21 can be easily obtained. , and to prevent deflection of the guide rails 31 and 32,
Even if the number of support points, that is, the support shafts 25 is increased, any errors in mounting each support shaft 25 to the guide rails 31, 32 are absorbed by the adhesive 26, so stress is generated on the guide rails 31, 32. There's nothing to do. Further, in the guide rail 31, the rollers 63 and 64 arranged on the base 21 side are
1, the space required between the guide rail 31 and the base 21 can be reduced due to the interposition of the rollers 63 and 64, and the support shaft 25 can be installed at an angle. The amount of protrusion from the side surface of the base 21 can be reduced, which is advantageous in terms of the cantilever-like support form. Furthermore, since the position of the gauge head support member 40 can be regulated by one guide rail 31, the engagement structure between the other guide rail 32 and the gauge head support member 40 can be made simple, and the precision can be reduced. Since there is no need to do this, product costs can be reduced from this point of view as well.

Further, two slider guide rails 46 and 47 are provided, and the positions of the slider guide rails 46 and 47 are shifted from each other in the front-rear direction (Y-axis direction).
The scale is supported on the back side of the slider 4 with a structure similar to that of the scale 33 of the guide rail 31.
It is desirable to mount the scale at least vertically or downwards in order to easily prevent the rotation of the 9 and to protect the scale.In this embodiment, the upper rail 46 focuses on holding the scale, and the lower rail 46 focuses on holding the scale. The rail 47 can receive vertical loads. Furthermore, by shifting both rails 46 and 47 in the front-rear direction, the height dimension can be reduced.

FIG. 4 shows a main part of another embodiment of the present invention, and in this embodiment, a shaft member 731 for configuring a guide rail etc. has only one straight portion in a cross section perpendicular to its axis. A concave groove 731A is formed in this straight portion along the axial direction (longitudinal direction) of the shaft member 731 so as to be parallel to the straight portion.

The shaft member 731 configured in this manner is supported by an appropriate support shaft 725 as shown by the two-dot chain line in FIG.
1, or supported at both ends like the slider guide rail 46 in the upper part of FIG. 1, or even like the spindle 52 in FIG. 1. It is used with the shaft member 731 side sliding.

In this embodiment, the same functions and effects as those of the previous embodiment can be achieved.

In the above embodiments, the present invention has been described as an example in which the present invention is applied to a three-dimensional measuring machine, but the present invention is not limited to this, and can be applied only to large measuring machines such as two-dimensional measuring machines and shape measuring machines. Small measuring instruments such as calipers, height gauges, dial gauges, or independent length measuring instruments that measure linear movement.
For example, it can be applied to linear scales (trademark), and even sliding parts of machine tools, etc. In short, it can be applied to measuring the amount of displacement of two objects that can move relative to each other in a linear direction. Furthermore, the application mode may be such that the shaft member side is fixed or movable, as long as it can be moved relative to the engagement member. Furthermore, scale 33,1
61 is not limited to optical reflective scales, but also includes light transmitting scales, electromagnetic scales, magnetic scales,
A capacitance type scale or even a contact scale may be used, and it goes without saying that the measurement unit 70 is also of this type. Also,
In the embodiment, the guide rail 31 as a shaft member,
32 has been explained, but the slider guide rails 46 and 4 in FIG.
7, two or more are provided on one side, and one of these
The book is used as a positional reference, and the rest is used as the measuring head support member 4.
A load of 0 may be applied. In this way, accuracy can be maintained over a long period of time. Further, the cross-sectional shape of the shaft member is not limited to one or two straight portions as in each of the above embodiments, but in short, it is sufficient if there is one or more straight portions, and at least one roller is in contact with the straight portions.

As described above, according to the present invention, adjustment is simple;
A displacement detector that is easy to maintain thereafter can be provided.

[Brief explanation of drawings]

Fig. 1 is a perspective view showing an embodiment in which the present invention is applied to a coordinate measuring machine, Fig. 2 is an enlarged front view of the main part with a part thereof cut away, and Fig. 3 is an engagement block of this embodiment. FIG. 4 is a cross-sectional view of main parts showing another embodiment of the present invention. 21...Base, 25,725...Support shaft, 31,4
6,52,731...Guide rail constituting shaft member, slider guide rail, spindle and guide rail, 31C,731C...Concave groove, 33,161,
733... Scale, 40... Gauge head support member, 53
... Measuring element, 54... Object to be measured, 61, 65... Engagement block as an engagement member, 62, 63, 64, 6
6, 67...Roller, 62A, 63A, 64A, 6
6A, 67A...support shaft, 62B...button, 70...
Measuring unit, 71... Index scale, 7
2... Light emitting element as a light emitting source, 73... Light receiving element as a light receiver.

Claims (1)

[Scope of Claims] 1. A roller group consisting of a shaft member whose cross section perpendicular to the axis has a straight portion and a circular arc portion, one roller in contact with the straight portion of the shaft member, and two rollers in contact with the circular arc portion of the shaft member. an engaging member having at least one set and capable of relative movement in the longitudinal direction of the shaft member; a scale attached to extend in the longitudinal direction on a straight portion of the shaft member; A displacement detector comprising: a detection section attached to the engagement member. 2. In claim 1, there is one roller in contact with the straight line portion and two rollers in contact with the circular arc portion.
A displacement detector characterized in that the rollers are attached to the engagement member so as to be in contact with the shaft member at 120 degree intervals. 3. The displacement detector according to claim 1 or 2, wherein the scale is of a reflective type, and the detection section includes a light emitting source, a translucent scale, and a light receiver. .