JPH0694476A - Encoder - Google Patents

Abstract

PURPOSE:To provide an encoder difficult to cause chattering or characteristic deterioration even in its long-term use by providing a position information pattern without patterning a conductor electrode on a code plate, and forming the sliding surface of a sliding element sliding on the code plate into nearly a flat surface consisting of the same material. CONSTITUTION:At least a part of a rotatably code plate 1 is formed with a resistor 3 having nearly a flat surface and irregular patterns (A-phase pattern 4 and B-phase pattern 5) on the reverse surface. Each siding element 7, 8, 9 is brought into contact with the surface of the resistor 3, and the sliding elements 7, 8 are slid along the A-phase pattern 4 and the B-phase pattern 5.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION In the present invention, when the relative position of a cord plate and a slider is changed, a signal of the amount of change (for example, rotation angle) and a signal of changing direction (for example, rotation direction) are generated. Regarding the encoder.

[0002]

2. Description of the Related Art A code plate for an encoder is usually constructed by providing a position information pattern on a surface of an insulative substrate by plating a conductor electrode of a predetermined shape with gold. By sliding the slider to change the relative position of the two, that is, by sliding the slider relative to the code plate, the slider is brought into contact with and separated from the position information pattern, A pulse signal is output each time the both contact.

For example, a code plate of a rotary encoder which has been generally used in the past is of two types which are composed of an annular conductor electrode having comb teeth of a predetermined pitch on a surface of a rotatable synthetic resin insulating substrate. A position information pattern (hereinafter, referred to as an A-phase pattern and a B-phase pattern) and a common pattern composed of ring-shaped conductor electrodes are concentrically provided, and the A-phase pattern and the B-phase pattern are in phase with each other. Are shifted by a quarter pitch. In addition, chattering is prevented by reducing the step between the surface of the insulating substrate on which the slider slides and the surface of each pattern as much as possible, that is, by forming the surface of the code plate that is the sliding surface to be substantially flat. To prevent. The terminal derived from the common pattern and the first phase contacting and separating from the A-phase pattern as the code plate rotates.
The terminal derived from the slider can output a pulse signal generated each time the slider comes into contact with the A-phase pattern. Similarly, the terminal derived from the common pattern and the rotation of the code plate can be output. 2nd contact and separation with the B-phase pattern
With the terminal derived from the slider, it is possible to output a pulse signal generated each time the slider comes into contact with the B-phase pattern, so that two pulse signals with a phase difference of 90 degrees can be extracted. it can. As a result, the rotation angle signal is obtained by counting the number of pulse signals, and the rotation direction signal is obtained from the difference signal between the two pulse signals.

An encoder of the type in which the code plate is fixed and the slider is rotated, and an encoder of the type in which the slider or the code plate is slid to change the relative position between the two are also known.

[0005]

As described above, in the conventional encoder, the slider slides on the code plate while alternately contacting the position information pattern and the insulating substrate to obtain the pulse signal. However, the insulating substrate made of synthetic resin is more likely to wear than the position information pattern made of metal.Therefore, if it is used for a long period of time, a step will occur between the surface of the insulating substrate and the surface of the position information pattern. It was difficult to avoid chattering that occurs when the pendulum collides. Further, if the abrasion dust of the insulating substrate or the position information pattern adheres to an undesired place, the waveform of the output signal changes, so that there is a possibility that the characteristics of the conventional encoder deteriorate significantly when used for a long period of time. Furthermore, in the conventional encoder, since the conductor electrode must be patterned and plated on the surface of the insulating substrate, the production cost of the code plate increases.

The present invention has been made in view of the above problems of the prior art, and an object thereof is to provide an encoder which is less likely to cause chattering and characteristic deterioration even when used for a long time at low cost.

[0007]

In order to achieve the above object, the present invention comprises at least a part of a code plate with a resistor having a substantially flat surface and an uneven pattern as a position information pattern on the back surface. Then, the slider was brought into contact with the surface of the resistor to slide the slider along the uneven pattern.

[0008]

According to the above means, since the thin portion and the thick portion are formed on the resistor in correspondence with the concave and convex pattern on the back surface, while the slider is in contact with the thin portion and the thick portion alternately. By sliding on the resistor, it is possible to output an electric resistance that changes according to the contact position of the slider. Further, since it is sufficient that the slider slides on the substantially flat surface of the resistor, even if it is used for a long period of time, there is no unevenness in the way of wear, so that the characteristic deterioration due to chattering or abrasion powder can be prevented.

[0009]

Embodiments of the present invention will be described below with reference to the drawings.

1 and 2 relate to an embodiment of the present invention. FIG. 1 is a plan view showing a code plate and a slider of a rotary encoder. Two kinds of position information patterns (A phase) provided on the code plate are shown. The pattern and the B-phase pattern) are partially omitted in the drawing. 2 is a sectional view taken along the line II-II in FIG.

The code plate 1 of the rotary encoder shown in FIGS. 1 and 2 is a disk-shaped metal substrate 2 formed by pressing a metal plate to form a large number of projections 2a and recesses 2b, and this metal. It is composed of a resistor film 3 formed by printing carbon ink on the surface of the substrate 2 and heating and curing it, and is rotatable. The surface of the resistor film 3 is formed to be substantially flat, but the concavo-convex pattern in which the convex portions 2a and the concave portions 2b of the metal substrate 2 are inverted is formed on the rear surface. Thus, the resistor film 3 is thin, and the resistor film 3 is thick on the recess 2b. Further, such a concavo-convex pattern of the resistor film 3 includes a ring-shaped A-phase pattern 4 in which thin-walled portions 4a and thick-walled portions 4b are alternately formed in the circumferential direction, and an A-phase pattern 4 among them. It is distinguished from an annular B-phase pattern 5 in which thin portions 5a and thick portions 5b are alternately formed along the circumferential direction on the circumferential side, and the phases of both patterns 4 and 5 are shifted by a quarter pitch. These A and B phase patterns 4 and 5 (concave and convex patterns) function as the position information pattern of the code plate 1. However, of the resistor film 3, the B-phase pattern 5
No unevenness is formed on the innermost ring portion 6 on the inner peripheral side of
The innermost annular portion 6 having a uniform film thickness functions as a common pattern of the code plate 1. The thin portion 4
The film thicknesses of a and 5a are set to about 5 μm, and the film thickness of the thick portions 4b and 5b are set to about 10 μm.

Then, on the surface of the resistor film 3, a first slider 7 is formed on the A-phase pattern 4, a second slider 8 is formed on the B-phase pattern 5, and an innermost ring is further formed. Since the common sliders 9 are elastically contacted on the portion 6, respectively, when the code plate 1 is rotated, the first slider 7 slides along the A-phase pattern 4 and The slider 8 is slid along the B-phase pattern 5, and the common slider 9 is slid along the innermost ring portion 6.

The rotary encoder configured as described above has an electric resistance between the first slider 7 and the common slider 9,
The rotation angle and the rotation direction of the code plate 1 are detected by respectively outputting the electric resistances between the second slider 8 and the common slider 9. That is, when the code plate 1 rotates, the first slider 7 moves to the A-phase pattern 4
When in contact with the upper thin portion 4a, the electric resistance is small,
Since the electric resistance increases when it is in contact with the thick portion 4b, the change in the electric resistance is output by the terminal 10 derived from the first slider 7 and the terminal 12 derived from the common slider 9. To be done. Similarly, when the code plate 1 rotates, the electrical resistance is small when the second slider 8 is in contact with the thin portion 5a on the B-phase pattern 5, and the electrical resistance is in contact with the thick portion 5b. Is larger, the change in the electric resistance is output by the terminal 11 derived from the second slider 8 and the terminal 12 derived from the common slider 9. Therefore, it is possible to extract two output signals that show a change in resistance value that reflects the rotation angle of the code plate 1 and have a phase shift of 90 degrees, and shape the output waveform by A / D conversion or the like to obtain the rotation angle. A signal and a rotation direction signal can be obtained.

As described above, in the above-described embodiment, the thin-walled portions 4a, 5a and the thick-walled portions 4b, 5b are formed on the resistor film 3 in correspondence with the concave-convex pattern (A-phase pattern 4 and B-phase pattern 5) on the back surface.
Is formed, and when each of the sliders 7 to 9 is slid on the substantially flat surface of the resistor film 3, the first and second sliders 7 and 8 on the resistor film 3 are formed. Since it is possible to output an electric resistance that changes according to the contact position and obtain a rotation angle signal and a rotation direction signal, the sliding surfaces of the sliders 7 to 9 are substantially flat surfaces made of the same material. A rotary encoder has been realized. As a result, even if the sliding surface is used for a long period of time, the sliding surface is worn in a uniform manner, and there is no possibility of causing a step,
Therefore, chattering can be avoided, and the characteristic deterioration due to abrasion powder can be prevented, and the product life is significantly improved.

Further, in the above embodiment, since the code plate 1 can be manufactured by a simple process such as pressing of a metal plate and solid printing of carbon ink, the productivity is high, the manufacturing cost is low, and the position of the uneven pattern is high. Since the precision can be controlled by the precision of the die of the press machine, it is easy to improve the resolution.

The inner bottom surface of the recess 2b of the metal substrate 2,
If an insulating material is interposed between the thick portions 4b and 5b of the resistor film 3 and the bottom surface of the thick portion 4b, 5b, the variation of the electric resistance output with the rotation of the code plate 1 becomes large. Waveform shaping becomes easy.

On the surface (flat surface) of the metal substrate having no unevenness, an insulating ink is printed in a desired pattern shape by a silk screen method or the like to form unevenness, and then a carbon ink is solidly printed to form a resistor. In addition to the advantage that if the coating is a film, the variation in the electrical resistance that is output with the rotation of the code plate will be large, and because the film thickness of the insulating ink is about 1 μm, the surface of the resistor film will be flatter. It has the advantage that it can be formed. However, since the insulating ink has to be printed in a pattern shape, the positional accuracy of the concavo-convex pattern on the back surface of the resistor film is slightly inferior to that in the above embodiment.

FIG. 3 is a plan view showing a code plate and a slider of a rotary encoder according to another embodiment of the present invention, and FIG.
4 is a sectional view taken along the line IV-IV in FIG. 3, and parts corresponding to those in FIGS.

The rotary encoder shown in FIGS. 3 and 4 uses, as the substrate of the code plate 1, a disk-shaped insulating substrate 13 having a large number of convex portions 13a and concave portions 13b formed on the surface by molding of synthetic resin. The surface of the insulating substrate 13 is provided with a resistor film 3 formed by printing carbon ink and heating and curing it. As in the above-mentioned embodiment, the surface of the resistor film 3 is formed to be substantially flat, but a concave-convex pattern in which the convex portions 13a and the concave portions 13b of the insulating substrate 13 are reversed is formed on the rear surface thereof. This uneven pattern has an annular A-phase pattern 4 in which thin portions 4a and thick portions 4b are alternately formed along the circumferential direction, and thin portions 5a and thick portions 5b in the circumferential direction. The phases of the patterns 4 and 5 are shifted by a quarter pitch. Further, the resistor film 3 is provided with an innermost annular portion 6 having a uniform film thickness on the inner peripheral side of the B-phase pattern 5, and the code plate 1
Is rotated, the first slider 7 slides along the A-phase pattern 4, the second slider 8 slides along the B-phase pattern 5, and the common slider 9 slides along the innermost annular portion 6.

That is, since the current flowing through the resistor film 3 along the rotating surface of the cord plate 1 does not easily flow in the thin portions 4a and 5a and tends to flow in the thick portions 4b and 5b, this rotary switch is used in the cord plate. When 1 is rotated, the electrical resistance between the first slider 7 and the common slider 9 and the electrical resistance between the second slider 8 and the common slider 9 are changed, respectively. Similar to the above-described embodiment, the rotation angle signal and the rotation direction signal are obtained by outputting the electric resistance that changes according to the contact position of the first and second sliders 7 and 8 on the resistor film 3.

Since the substrate of the code plate 1 is the molded insulating substrate 13, this embodiment can further reduce the cost as compared with the above-mentioned embodiment, and the code plate 1 can be lightened and rotated. There is an advantage that it becomes easier.

In each of the code plates of the above-mentioned embodiments, a resistor film is provided on the surface of a substrate having irregularities, but the surface is made of conductive plastic containing carbon powder or the like. If a plate-shaped resistor having a substantially flat surface and a concave-convex pattern on the back surface is molded, the resistor can be used as it is as a code plate.

Further, a single-phase rotary encoder for detecting only a rotation angle signal, a rotary encoder of a type in which a code plate is fixed and a slider is rotated, and a slider or a code plate is slid to make the relative between them. It goes without saying that the present invention is also applicable to a slide type encoder that changes the position.

[0024]

As described above, the slider is slid on the substantially flat surface of the resistor having the concavo-convex pattern as the position information pattern on the back surface, and the slider is formed into the thin portion of the resistor. According to the present invention configured to output an electric resistance that changes according to the contact position while alternately contacting the thick portion,
Since the sliding surface of the slider is a substantially flat surface of the resistor, even if the sliding surface is used for a long period of time, the sliding surface is worn evenly and there is no risk of causing a step, and therefore chattering can be avoided. It has the remarkable effect of preventing the characteristic deterioration due to abrasion powder, and the code plate can be easily manufactured by solid printing the resistor on the substrate or molding the resistor using conductive plastic. In addition, the productivity can be improved, and as a result, an excellent encoder having a long product life can be provided at low cost.

[Brief description of drawings]

FIG. 1 is a plan view showing a code plate and a slider of a rotary encoder according to an embodiment of the present invention.

FIG. 2 is a sectional view taken along line II-II in FIG.

FIG. 3 is a plan view showing a code plate and a slider of a rotary encoder according to another embodiment of the present invention.

FIG. 4 is a sectional view taken along line IV-IV in FIG.

[Explanation of symbols]

 1 Code Plate 2 Metal Substrate 2a Convex 2b Recess 3 Resistor Film (Resistor) 4 A-Phase Pattern (Roughness Pattern) 5 B-Phase Pattern (Roughness Pattern) 4a, 5a Thin Wall 4b, 5b Thick Wall 6 Innermost Circle Ring portion (common pattern) 7, 8, 9 Slider 13 Insulating substrate (resin molded product) 13a Convex portion 13b Recessed portion

Claims (3)

[Claims] 1. A code plate provided with a position information pattern, and a slider that slides relative to the code plate, the position of which depends on the positional relationship between the slider and the position information pattern. In the encoder for changing the output signal by means of the above, at least a part of the code plate is composed of a resistor having a substantially flat surface and a concave-convex pattern as a position information pattern on the back surface, and the above-mentioned sliding on the surface of the resistor. An encoder characterized in that a child is brought into contact with the slider to slide along the uneven pattern. 2. The encoder according to claim 1, wherein a metal plate having a large number of irregularities formed on a surface thereof is used as the substrate of the code plate, and the resistor is provided on the metal plate. 3. The resin molding according to claim 1, wherein a resin molded product having a large number of irregularities formed on the surface is used as the substrate of the code plate, and the resistor is provided on the resin molded product. Encoder.