JPH0127041Y2 - - Google Patents

Description

[Detailed description of the invention] The present invention is a scanning device for a length measurement scale in a digital length measurement device that measures the length of an object to be measured;
In particular, the present invention relates to an improvement in a scale scanning device that is supported by a guide surface along the scale and scans the scale surface.

A digital length measuring device that measures the length of an object by scanning the scale with a scanning device supported by a plurality of radial bearings that roll in contact with a guide surface along the length measuring scale is known, for example, from Japanese Patent Application Laid-Open No.
It is already known from the published patent application No. 53-125056. As shown in FIG. 1, the scale scanning device of this conventionally known length measuring device is provided with a plurality of sets of at least two radial bearings 2, 2' installed front and rear in the scanning direction. It is characterized in that the axial spacing of each pair of radial bearings 2, 2' is larger than the joint gap 3 of the guide rail. In this device, the radial bearings 2 and 2' do not fall into the joint gap 3, so
It is particularly suitable for scanning the length measurement scale surface 1 along the guide surfaces 4, 4a, and 4b that have seams. However, the radial bearings 2, 2' that support the scale scanner body 5 and are in contact with the guide surfaces 4, 4a, 4b are directly attached to the scale scanner body 5, and their positions cannot be adjusted. Because it is necessary to ensure that the outer circumferential surfaces of multiple radial bearings that are in contact with the guide surface are in contact with one plane at the same time, extremely high accuracy is required for the shaft hole machining of the scale scanning device body that is machined to install the radial bearings. It is also necessary to have extremely small differences between the bearings and the shafts that support them, but it is difficult to achieve such high precision.

The purpose of the present invention is to solve the above-mentioned conventional drawbacks and to obtain a scale scanning device that does not require high processing precision and can extremely easily and reliably make the radial bearing always contact the same plane. .

Hereinafter, the present invention will be described in detail according to embodiments shown in the accompanying drawings.

FIG. 2 is a plan view showing an embodiment of the present invention in which the surface and side surfaces of the scale member are used as guide surfaces, and FIG. 2A is a sectional view taken along the line AA in FIG. A glass scale 1 is installed along the longitudinal direction inside a hollow groove-shaped member 11 that is fixed to a fixed part such as a bed or a movable table of a measuring machine or a machine tool.
2 is permanently installed. A guide surface is formed on the front surface 12a and side surface 12b of this glass scale 12, and a plurality of radial bearings 14, 14' that support a scale scanning device main body 13, which will be described in detail later, are formed.
are configured to roll into contact. The scale scanning device main body 13 is connected to a relative displacement member 16 via a connecting member 15, such as a piano wire, which is flexible and acts as a rigid body under compression and tension. As is clear from FIG. 2, the direction in which the connecting member 15 acts as a rigid body is the longitudinal direction of the hollow groove-shaped member 11 (glass scale 1
2), and as a result,
In the direction in which the main graduations of the glass scale 12 are marked, the scale scanning device main body 13 and the relative moving member 1
6 does not move relative to the relative moving member 1.
6 is directly transmitted to the scale scanning device main body 13. Furthermore, due to the flexibility of the connecting member 15, the radial bearing 1 of the scale scanning device main body 13
4 is urged to come into pressure contact with the glass scale 12. The structure of such a connecting member is described in, for example, Japanese Patent Application Laid-Open No. 1974-74554. When the hollow groove-shaped member 11 is installed in a fixed part, this relative movement member 16 moves the hollow groove-shaped member 11
When the hollow groove member 11 is provided on the moving table side, the relative moving member 16 is provided on the fixed part side.

Therefore, the scale scanning device main body 13 connected to the relative moving member 16 can move integrally with the relative moving member 16 relative to the glass scale 12 in the longitudinal direction in which the length is to be measured. Also,
A compression spring 17 inserted between the side surface 13a of the scale scanning device main body 13 and the relative movement member 16 allows the radial bearing 14' to move against the glass scale 12.
is biased so as to come into pressure contact with a guide surface formed on the side surface 12b. A detection scale window 19 is provided at approximately the center of the scale scanner body 13, facing the incremental main scale 18 provided on the glass scale 12; Four detection scales 20 are provided, and a detection light receiving element 2 is provided on the opposite side of the glass scale 12 from the detection scales 20.
1 is provided. Detection scale 20 and main scale 1
8 is illuminated by an illumination device (not shown), the light passing through both scales 18 and 20 is detected by the light receiving element 21, and the length to be measured is measured using the detection signal. When a particularly long glass scale is required, a small interval
Another glass scale 12' with S ₁ is provided facing each other in the length measurement direction. In this case, the hollow groove-shaped member 11 may also be butted and joined to another hollow groove-shaped member 11'.

The bearing device 22 that supports the scale scanning device main body 13 includes a set of two radial bearings 14 or one
4' to form one unit, and one set of bearing devices and two sets of bearing devices are arranged on one side and on the other side of the detection scale window 19 of the scale scanning device main body 13.
Two sets of bearing devices 22 are also provided on the side surface 13a of the scale scanning device main body 13. This bearing device 22 includes a bearing support frame 23 and a radial bearing 14 attached by a shaft 24, as shown in FIG.
and a pin 25 provided on the side surface of the bearing support frame 23.
It is composed of.

4 is a plan view of a portion to which the bearing device 22 is attached, FIG. 4A is a sectional view taken along the line AA in FIG. 4, and FIG. 4B is a side view taken in the direction of arrow B in FIG. The bearing device 22 is inserted into a rectangular hole 13b provided in the scale scanning device main body 13 and is slightly larger than the bearing support frame 23, and is supported by the scale scanning device main body 13 so as to be rotatable about the pin shaft 25. ing. A set screw 26 is screwed into this rectangular hole 13b so as to be able to rotate from the outside, and the position of the radial bearing is adjusted by rotating the bearing device 22 around the pin shaft 25. In FIG. 2, three sets of six radial bearings 14 can be assembled so as to contact the surface of the glass scale 12, and two sets of four radial bearings 14' can be assembled so as to simultaneously contact the glass scale side surface 12b. After the adjustment is completed, it is fixed with two set screws 26.
In addition, if it is necessary to change the interval between the main scale 18 and the detection scale 20 on the glass scale 12, remove the pin 25 from the bearing support frame 23, slide the bearing support frame 23, and place it on the glass scale surface. After adjusting the position by displacing it up and down, set screw 2
It is sufficient to fix it at 6.

FIG. 5 shows another embodiment of the bearing device 22, and FIGS. 5A and 5B are sectional views taken along the lines AA and BB in FIG. 5, respectively. In this embodiment, the bearing support frame 23' has a rib 23'a at its center.
A leaf spring is attached to the rib 23'a, and both ends of the plate spring engage with the edges of the rectangular hole 13b of the scale scanning device main body 13 to always bias the bearing support frame 23' in a direction away from the glass scale 12. 27 are provided. In addition, the rectangular hole 1 of the scale scanning device main body 13
3b is formed with a protruding step 13b', and an adjustment screw 28 provided through this protruding step 13b' adjusts the distance between the glass scale 12 and the scale scanning device main body 13 and each radial direction. Bearing 1
4 relative to the scale scanning device main body 13 is adjusted. After completing the adjustment, the bearing support frame 23'
is fixed to the inner wall surface of the rectangular hole 13b of the scale scanner main body 13 by a set screw 26'.

FIG. 6 is a plan view showing still another embodiment of the bearing device 22, and FIG. 6A is a sectional view taken along the line AA in FIG. The rectangular hole 13b of the scale scanner main body 13 has a ceiling portion 13b'' as shown in FIG. In addition, the rib 23a'' formed at the center of the bearing support frame 23'' and the ceiling portion 13 of the rectangular hole 13b are connected to each other.
By rotating the adjusting screw 29 against the biasing force of the compression spring 30 inserted between the The position relative to the scale scanning device main body 13 can be adjusted. After completing the adjustment, tighten the set screw 26''
As a result, the bearing support frame 23'' is fixed to the inner wall surface of the rectangular hole 13b.

FIG. 7 is a perspective view of an embodiment in which the pin 25 in FIG. 3 is also used as one side of the shaft 24, and FIG. 8 is a plan view of a portion where the bearing device of FIG. 7 is attached.
FIG. 8A is a side view of FIG. 8 in the direction of arrow A.
As shown in FIG. 7, the bearing device 22 in this embodiment has two radial bearings 14a and 14b, a bearing support frame 23, a short shaft 24 that supports one radial bearing 14a, and a shaft that passes through the bearing support frame 23. The long shaft 24' supports the other radial bearing 14b and rotatably supports the bearing support frame 23. In this case, the long shaft 24' is inserted through the rectangular hole 13b of the scale scanner main body 13 as shown in FIG. 8, so that the radial bearing 14b is supported by the scale scanner main body 1
Although the relative position with respect to 3 remains unchanged, one radial bearing 14a can rotate together with the bearing support frame 23 around the long axis 24'. Therefore, radial bearing 1
The rotation can be adjusted so that one radial bearing 14a contacts the surface that contacts 4b. After the adjustment is completed, the bearing support frame is fixed to the inner wall surface of the rectangular hole 13b using the set screw 26.

In all of the bearing devices 22 of the embodiments shown so far, two radial bearings are provided within a bearing support frame, and these are treated as one unit within a plurality of rectangular holes 13b formed in the scale scanning device main body 13. It is of the type that is directly fixed. In this way, instead of directly fixing the bearing frame, it may be fixed to a swingable arm and the arm may be displaced to adjust and fix the position of the radial bearing.

FIG. 9 is a side view of an embodiment in which a bearing device 122 using an arm is attached to the scale scanner body, FIG. 9A is a plan view of FIG. 9, and FIG.
FIG. 10A is a plan view showing another embodiment of the scale scanning device equipped with the bearing device shown in FIG.
-A sectional view.

In FIG. 9, a bearing support plate 31 supporting two radial bearings 14 is rotatably supported by an arm 33 by a pin 32, and fixed through a hole (not shown) provided at the tip of the arm 33. It is fixed to the arm 33 by a screw 34. Further, the arm 33 is supported so as to be swingable around a pin shaft 35 grafted onto the side wall of a rectangular hole 113b provided in the scale scanning device main body 113 (see FIG. 10).
It is fixed to the side wall of the rectangular hole 113b by a fixing screw 37 passing through a hole 36 provided in the side wall of the rectangular hole 113b. Since this bearing device 122 has the above structure, first loosen both the bearing support plate fixing screw 34 and the arm fixing screw 37, and then
The two radial bearings 14 are brought into contact with the guide surface 12a on the surface of the glass scale 12, and in this state, the distance between the scale scanning device main body 113 and the glass scale 12 is adjusted to a predetermined height. At this time, the bearing support plate 31 rotates around the pin 32, and the arm 3
3 rotates around a pin shaft 35. When the height adjustment is completed, first tighten the arm fixing screw 37 to fix the arm 33, then adjust so that the two radial bearings 14 are in contact with the glass scale 12 at the same time, and after completing the adjustment, The bearing support plate 31 is fixed to the arm 33 by tightening the bearing support plate fixing screw 34.

This bearing device 122 has a bearing mounting plate fixing screw 3.
Glass scale 1 because 4 is to be tightened from the outside.
2 and the scale scanning device main body 113 is wider than the embodiment shown in FIG. Therefore, in order to maintain a predetermined distance between the detection scale 20 and the glass scale 12, the detection scale window 119 is provided to protrude toward the glass scale as shown in FIG. 10A. Further, the widths of the hollow groove-shaped member 111 and the relative movement member 116 are made wider than those in FIG. 2A by a length corresponding to the protrusion amount of the detection scale window 119. Other figures 10 and 10A
In the figure, the same reference numerals as those in FIG. 2 and FIG. 2A are used in common, so the explanation will be omitted.

Now, as is clear from the plan views of FIGS. 2 and 10, there are two sets of bearing devices 22, 122 in contact with the guide surface 12a on the surface of the glass scale 12, one set on one side and one set on the other side with the main scale 18 as a boundary. A substantially triangular shape is formed by these bearing devices. Among them, the total of four radial bearings in one of the two sets of bearing devices can be reduced to a minimum of three.

FIG. 11 is an explanatory diagram of the embodiment, where A is a conventionally known radial bearing fixed to the main body of the scale scanning device, and B and C and D and E are two radial bearings each used in the adjustable bearing device of the present invention. A set of radial bearings. In addition, five radial bearings A,
The bearing spacing in the length measurement direction of B, C, D, and E is determined to be larger than the spacing S ₁ shown in FIG. 2 or FIG. 10. Also, the center of pressure G applied to the scale scanner body in the direction of the glass scale (the center of gravity of the scale scanner body in FIGS. 2 and 10) is different from the bearings AE, C-D, and B in FIG. -D and B-E (within the shaded area in the figure), any one of these five radial bearings will pass over the seam spacing S ₁ . However, the scale scanner body will not tilt with respect to the glass scale surface. In the embodiment shown in Fig. 11, one bearing A among the three radial bearings arranged in the length measurement direction is an independent single bearing, but three radial bearings A, B, and C are The bearing device may be configured as a set. At this time, the radial bearings A, B, and C are attached in advance to a bearing support frame or the like so that the three points simultaneously contact the glass scale. This has the advantage that the work of adjusting and fixing the bearing device becomes easier.

Furthermore, the radial bearing used in the present invention is not limited to a rolling bearing such as a ball bearing, but may also be a simple roller that is supported by a shaft and rotates.

As described above, according to the present invention, a bearing device is configured as a set of a plurality of radial bearings, and this bearing device is attached and fixed to the scale scanning device in an adjustable manner. , there is no need to strictly define machining accuracy. Moreover, a scale scanning device with a simple structure and high performance can be obtained.

[Brief explanation of the drawing]

Figure 1 is a plan view of a conventional length measuring device, and Figure 2 is a
A plan view of the embodiment of the present invention, FIG. 2A is A of FIG.
-A sectional view, FIG. 3 is a perspective view of the bearing device used in the embodiment of the present invention, and FIG. 4 is a partial plan view of the embodiment of the present invention equipped with the bearing device of FIG.
Figure A is a sectional view taken along the line A-A in Figure 4, Figure 4B is a side view of Figure 4 seen from direction B, and Figures 5 and 6 each show a bearing device with different adjustable fixing means. FIG. 5 is a partial plan view of the embodiment of the present invention used.
Figures A and 6A are sectional views taken along line AA, Figure 5B is a sectional view taken along line BB in Figure 5, Figure 7 is a perspective view showing a modified example of the bearing device, and Figure 8 is a sectional view taken along line BB in Figure 4. FIG. 8 is a perspective view of an embodiment with a different shaft than the bearing device;
The figure is a partial plan view of an embodiment equipped with the bearing device shown in Fig. 7, and Fig. 8A is a side view seen from direction A in Fig. 8.
Fig. 9 is a side view of a bearing device using an arm as a fixing means, Fig. 9A is a plan view of Fig. 9, and Fig. 10 is different from Fig. 2 of the present invention equipped with the bearing device of Fig. 9. FIG. 10A is a plan view of the embodiment of FIG.
A sectional view and FIG. 11 are explanatory diagrams showing one embodiment of the mutual positions of radial bearings used in the present invention. 12... Scale member, 12a, 12b... Guide surface, 13, 113... Scale scanner body, 14, 14a, 14b, 14'... Radial bearing, 16, 116... Relative movement means, 23, 2
3', 23'', 31, 33...bearing support means, 2
6, 26', 26'', 34, 37...fixing means.

Claims (1)

[Claims for Utility Model Registration] It has a scale member formed by adding scale plates formed with scales so that the scales are continuous, a scale scanning device for reading the scale, and a scale member configured by adding scale plates formed with scales so that the scales are continuous; In a length measuring device having a plurality of sets of at least two radial bearings arranged at larger intervals in the scanning device and rolling with the scale plate surface as a guide surface, each set of the radial bearings a plurality of supporting bearing devices; a position adjusting means for adjusting the position of each of the bearing devices so that all of the supported radial bearings are in contact with the scale plate surface; A length measuring device characterized by comprising: a fixing means for fixing the device to the device;