JPS61195301A - Linear scale reading device with moving object itself as scale - Google Patents

Abstract

PURPOSE:To drastically elevate reading accuracy by forming a sensor from dots or very fine lines in the measuring direction to provided a sensitive surface of very narrow width and by outputting signals corresponding to the distance from the sensor to a linear scale. CONSTITUTION:An object 10 to be inspected includes a high dielectric constant material 1 such as an iron alloy and a low dielectric constant material 2 such as a chromium plating layer having an approximately flat surface in the measuring direction. The linear scale 3 is formed on the upper surface of the high dielectric constant material 1 as a square U-shaped slot on which the chromium plating layer 2 with a thickness equal to D is formed. The depth (d) of the slot forming the linear scale 3 is 20-150mum with the pitch being about 1mm. Two sensors 4 are provided with a phase shift in the measuring direction so as to be in abutment with and relatively movable to the object 10 to be inspected in the measuring directions 8, 8'. Each sensor 4 is of the inductance type H sensor and has the sensitive surface 11 complementary to a linear surface 9 of about 0.5mm width in the measuring direction at the end contacting with the surface 9.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention can be used for adjusting roller gaps in machine tools, XY tables, minute feed cylinders, rolling mills, etc.
The present invention relates to a linear scale reading device that can use a moving object itself such as a sliding surface as a scale.

(Prior art) It is known that micro-position reading devices used in the above-mentioned fields place scratches or colors on the surface of an object to be inspected and read them using electric, magnetic, or optical means. Needs to be blemished or colored. When the lubricated surface is not scratched or colored, such as in the case of an XY table, a scale linked to the lubricated surface is provided for reading. In this case, there were drawbacks such as a complicated structure and additional link errors. In addition, electromagnetic steel plate thickness gauges (for example, see page 60 of ``Senna's Function and Optimum Utilization'' by the Japan Regulator and Sensor Study Group, published by Gijutsu Hyoronsha on March 10, 1980) can distinguish between magnetic and non-magnetic materials. Although there are devices that measure the distance between the boundary of the border and the sensor,
Conventional inductor sensors are so-called E-type (see FIG. 5) type sensors, as will be explained in detail later, and cannot respond to small differences in inductance. That is, the tip of the E-type sensor has a sensing surface with a width of at least 3u or more, and cannot read fine pitches. This required the use of a coarse pitch scale and sophisticated electrical processing of the output signal from the sensor.

(Problems to be Solved by the Invention) An object of the present invention is to provide a method for reading the minute position of an object to be inspected, in which a moving object itself such as a sliding surface having a flat and rough surface can be used as a scale. The object of the present invention is to provide a near-scale A reading device that uses a moving object itself as a scale and can read minute positions with a high resolution of about 0.1 u, although it is relatively inexpensive.

(Means for solving the problem) For this reason, the present invention is designed to prevent the formation of a boundary between a high-permittivity material and a low-permittivity material inside or on the surface, even if the surface is almost flat in the measurement direction. an object to be inspected having a linear scale, and a sensor disposed so as to be movable relative to the surface in the measurement direction, the sensor having a very narrow sensitive surface forming a point or a very thin line in the measurement direction. The moving object itself can be used as a scale or can be used as a near scale reading device, which is characterized in that it can have a surface and can output a signal corresponding to the distance from the sensor to the flaw.

(Function) According to such a configuration, the low dielectric constant material surface is almost flat, such as a flat chrome plated surface, and the inside has a thickness of about 1 mm.
By using the linear scale of the object to be inspected, which is a high permittivity material with linear scale grooves as shown below and can be used as a sliding surface, and using a sensor with a sensing surface that is extremely narrow in the measurement direction, the phase can be determined. The present invention provides an IJ near-scale reading device that can directly read minute positions with a high resolution of, for example, 0.1 mm without any control or other processing. Since the device does not require a scale linked to the surface, it has a simple structure and is inexpensive, and since no link errors are added, the device has a direct and higher reading accuracy.

It has an order of magnitude higher resolution than conventional electromagnetic steel sheet thickness gauges, and is also smaller and cheaper.

(Example) Next, an example of the present invention will be described with reference to the drawings.
Figure 1 shows a schematic cross-sectional view of a contact type linear scale reader. The first inspection object αO is made of a high dielectric constant material (1) such as an iron alloy, and is approximately half flat in the measurement direction (818'). a low dielectric constant material (2), such as a chrome plated layer, having a surface (9). On the upper surface of the high dielectric constant material (1), a linear scale (3) is formed as an angular U-shaped scale in the case of the embodiment, and a linear scale (3) with a medium thickness, for example 20. A chrome plating layer having a normal thickness is formed as a low dielectric constant material (2).The depth (d) of the entire formed surface of the linear scale (3) is 20 μm to 150 μm in the example, and the pitch (P) is is approximately 1 bird. In the embodiment, two sensors (4) are arranged so as to be in contact with the object to be inspected αO in the measurement direction (818') and to be movable relative to each other, with their phases shifted in the measurement direction. Each sensor (4) is an inductor H-type sensor, which will be described later, and the tip in contact with the surface (9) has a diameter of approximately 0.5 mm in the measurement direction.
A linear sensitive surface α having a width of u and complementary to the surface (9)
has η. Each sensor (4) is supported by a support (5) and a spring (7) is inserted between the inner member (5) and the outer member (51) fixed to the sensor holder (6).
The sensor (4) is brought into contact with the surface (9) under a constant load. The sensor (4) is a so-called inductor H-type sensor, which was invented by Yukio Ogawa, a co-inventor of the present invention. ') It is an inductance H-type sensor that has a very narrow sensitive surface that forms a K point or an extremely thin line, and can output a signal corresponding to the distance from the sensor (4) to the flaw (3). be. That is, in the example, as shown in FIG. 3, the distance (G) between the sensor sensing surface αp and the surface (91) of the high dielectric constant material (1) and the output of the sensor (4) are expressed as (1)). It is used within a roughly proportional range. and sensor (4
) can be machined, so it can have various shapes as shown in FIG. By doing so, it is possible to have an extremely narrow sensing surface αη in the measurement direction (8), either as a point or as a very thin line. For example, by setting @(R) of the sensitive surface αη to 0.51111 or less, a resolution of 0.1+1 Jl can be obtained. This principle is schematically shown in FIG. Figure 5 shows the conventional so-called E for electromagnetic thickness measurement as described above.
The α4 type sensor has a figure-8 cross section, requires a wide sensing surface (11') in the measurement direction, and therefore has a resolution of several millimeters.In contrast, the inductor sensor described above The H-type sensor (4'+, Fig. 4(b)) transmits the magnetic flux to a narrow (R") sensitive surface (11').
can be collected to have . Then, by further sharpening the tip, the sensing surface (1) is extremely narrow.
1, Fig. 4 (9)]. Fig. 7 is a block diagram of a dynamic signal reading circuit when only one inductor H-type sensor (4) is used, and the signal of the sensor (4) is processed by a processing circuit αJ1, that is, an oscillation circuit α4, a rectifier circuit αe1, a zero adjustment circuit αQ and analog/digital output circuit αη,
The output is output to a predetermined output device. These processing circuits←
3 can use a well-known circuit and does not form part of the present invention, so it will not be described in detail. The inductor H-type sensor (4) and the oscillation circuit α4 in FIG. 7 are parallel oscillator circuits, and their Q decreases as they approach the high dielectric constant material (1). Therefore, the amplitude of the oscillator attenuates depending on the distance to the high dielectric constant body (1), so this signal is rectified by a rectifier circuit α$ and guided to a zero adjustment circuit μG including a threshold switch to control the output. .

Further, since analog output is proportional to distance (G) within a certain range, minute displacements (flaws) can be detected by filtering the output.

For example, if the sensor (4) and the object to be inspected αq are kept at a constant distance and the object to be inspected αO is moved in parallel, the sensor (4) can detect the flaw (3) in the moved part as a change in inductance. In this case, since it is a dynamic signal, only the alternating current signal is output and filtered to accurately amplify the amount of change by 10 to several hundred times, making it reliable and increasing accuracy by 70 times. It is possible to increase the resolution. FIG. 1θ shows a processing circuit (13') when two inductor H-type sensors (4) as shown in FIG. 1 are used. Such a processing circuit (as many as 13 well-known circuits may be used and will not be described in detail since they do not form part of the invention. In FIG. 10, the two inductor H-type sensors (4) forming the differential sensor are When two inductor H-type sensors (4) with the same characteristics are connected in series and AC signals with a phase difference of 180' are input to each end through a phase discriminator (c), the sensor (4)
From the midpoint of (4), the difference in the inductors Q1 of the two sensors can be taken as the difference in amplitude. The difference signal of Q' with this phase characteristic is converted into a 10 to several hundred times difference amplifier (2
), the phase discrimination circuit (a) discriminates between the fundamental phase of the Colpitts oscillator and the phase of the difference signal, and the signal is output via a rectifier circuit (c) and an output circuit (a). The processing circuit in Figure 10 (13 is a so-called differential sensor signal processing circuit, which, as is well known, can firstly capture the signal statically. As shown in Figure 7, it can dynamically capture the signal. However, by using a differential system as shown in Figure 10, it is possible to prevent undetected errors from a stationary state and at both points n1.Secondly, By using a differential system, the initial characteristics of each sensor are canceled out.Thirdly, since two sensors are used, a phase difference can be given, and processing resolution can be increased. Figure 2 shows the surface (91
An example will be shown in which a contact type sensor (Fig. 1) cannot be used, such as when the contact sensor (see Fig. 1) is easily covered with dust or the like. Structural action is the first
Although similar to that shown, the accuracy can be reduced by a factor of 10-100.

(α) As shown in Figure 81, by making the groove that is the linear kale (3) into an angular U-shape,
) As shown in 1 groove (3), it is possible to raise 2 signal take-out points. The surface formed by the high dielectric constant material (1) (9 areas is baked with a laser etc., and the low dielectric constant band scale (31) at a predetermined depth is formed.
It is possible to take a pitch of 10 gm. 11) shows the surface (9'') on which a coating (c) of a high hardness, low dielectric constant material such as chrome plating is applied.

In the above embodiments, the low dielectric constant material (2) forming the surface (9) is described.
) is plated with chrome, but it may be plated with Teflon or the like, and the surface (9) may have dust, oil, etc., or small irregularities. Furthermore, the high or low dielectric constant material here refers to a material that has a dielectric constant different from that of the other material and that demarcates the boundary between the two, so it may be a steel plate and air, or it may be a sensor (4
) is shown using an inductance distance sensor in the example, but if the sensing surface (b) is extremely narrow, other types of sensors such as conductive type, capacitance type, thermal conductivity measurement type or ultra high frequency type sensor may be used. It may be.

(Effects of the present invention) As described above, the present invention provides a linear scale reading device that can read minute positional displacements with an extremely high resolution of approximately 0.19, and the surface of which forms a lubricated surface. A flat surface can be used, so for example, create a micro groove directly on the sliding surface of an XY table, NO machine table, etc., and then apply regular chrome plating such as 2Q/Zm on it, and attach the sensor to the other party's table''! or bet. By embedding the scale in a supporting part such as the like, it is now possible to directly read the scale, that is, the boundary between the high and low dielectric bodies, providing a linear scale reading device with a simple structure and extremely high reading accuracy. Therefore, the present invention can be used in other devices that require minute position reading, such as roller gap adjustment in rolling mills and paper-making machines, minute feed cylinders, and the like.

[Brief explanation of drawings]

1 and 2 are schematic cross-sectional views showing different embodiments of the present invention, FIG. 3 is an explanatory diagram of the operation of the sensor shown in FIG. 2, and FIG. 4 is an illustration of the operation of the sensor shown in FIG. 6 is a side view showing the different patterns of the sensor according to the embodiment of the present invention and their effects; FIG. 5 is a side view showing an example of a conventional E-type sensor; and FIG. Or use the sensor shown in Figure 2 as 1
FIGS. 8 and 9 are cross-sectional views and corresponding signal output graphs illustrating different embodiments of the present invention. FIG. 10 is a block diagram showing a static processing circuit when the two inductor H-type sensors shown in FIG. 1 are used, and FIG. 11 is a top view showing a test object different from that shown in FIG. 1. 1...High dielectric constant material 2...Low dielectric constant material 3...
・Linear scale (square U-shaped groove) 3'...
Linear scale (square groove) 31...Low dielectric constant scale

Claims (9)

[Claims] (1) An object to be inspected that has a surface that can be made almost flat in the measurement direction and has a linear scale formed by a boundary between a high dielectric constant material and a low dielectric constant material inside or on the surface; a sensor disposed so as to be relatively movable abutting or adjacent to the sensor, said sensor having a very narrow sensitive surface forming a point or a very thin line in said measurement direction and extending from said sensor to said sensor. A linear scale reading device using a moving object itself as a scale, characterized in that it is capable of outputting a signal corresponding to the distance to the linear scale. (2) In the device according to claim 1, the linear scale includes a linear scale groove provided on the outer surface of the high dielectric constant material and a low dielectric constant material coated on the outer surface and forming the surface. A linear scale reading device that uses the moving object itself, which is the boundary portion of the structure, as a scale. (3) In the device according to claim 1, the linear scale is the surface formed by the high dielectric constant material, or the surface formed by coating the high dielectric constant material with a low dielectric constant material; In contrast, a linear scale reading device in which a moving object itself, which is the boundary portion defined by a low dielectric constant scale of a certain depth on the outer surface of the high dielectric constant body, is used as a scale. (4) In the device according to claim 2, the linear scale groove is a groove formed in the iron-containing metal surface and has a pitch of about 1 mm or less when viewed in the measurement direction, and A linear scale reading device that uses a moving object itself as a scale, and has a surface made of chrome plating with a thickness of about 20μ. (5) In the device according to claim 3, the linear scale is formed as a partial low dielectric constant band on the surface formed by the iron-containing metal surface by partial surface hardening such as laser baking. A linear scale reading device that uses the moving object itself as a scale. (6) In the apparatus according to claim 5, the linear scale uses a moving object itself as a scale, the surface of which the linear scale of the low dielectric constant band is formed with a coating of a high hardness low dielectric constant material. reading device. (7) In the device according to claim 4, the cross section of the linear scale groove in the measurement direction has an angular U shape.
A linear scale reading device that uses a moving object itself as a scale. (8) In the device according to any one of claims 1 to 7, the sensor is an inductor H having a region capable of outputting a sensor signal substantially proportional to distance.
A linear scale reading device that uses a moving object itself as a scale, and the sensing surface at the tip of the sensor can read with a resolution of about 0.11. (9) The device according to claim 8, wherein the linear scale reading device uses a moving object itself as a scale, in which a plurality of sensors are arranged with a phase shift in the measurement direction.