JP2007155636A - Rotary encoder - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a rotary encoder capable of simply adjusting locations between a light receiving element and a magnetic detection element and easily being assembled by fixing the light receiving element and the magnetic detection element to a sub substrate and bonding the sub substrate to a main substrate. <P>SOLUTION: This encoder consists of a rotational disk plate, a light source and the light receiving element which performs photoelectric conversion of light from the light source, a magnetic pattern forming means arranged on the rotational disk plate, and at least one magnetic detection element arranged at a location opposing to the magnetic pattern forming means. The light source is fixed/arranged on a spindle substrate which rotatably supports the rotational disk plate, and a substrate having an output signal processing circuit is arranged on an opposing side with the rotational disk plate therebetween. The sub substrate carrying the light receiving element is mounted on the substrate, and the magnetic detection element is integrally fixed to the sub substrate. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a rotary encoder for detecting the rotation angle of various rotating shafts of industrial equipment, consumer equipment, and the like. Specifically, an optical pattern and a magnetic pattern are formed on a rotating disk plate connected to a detected shaft, and this pattern is received. The present invention relates to a rotary encoder that detects a rotational speed and an angular position of a detected shaft by detecting with an element and a magnetic detection element.

  Generally, this type of rotary encoder has a rotating disk plate connected to a detected shaft, detects an optical pattern or a magnetic pattern such as a translucent slit on the disk plate, and is a light receiving element or a magnetic detecting element arranged opposite to the disk plate. It is widely known as a detection device. Then, an optical or magnetic pattern is output as a pulse signal of a predetermined period by the detection element, and this pulse signal is integrated on various external devices to detect the angular position, and a different pattern is formed for each angular position. Thus, an absolute method for detecting the absolute position of the rotating disk plate is known. As described above, a pattern formed on the rotating disk plate is known to be an optical type and a magnetic type or a combined type including both. The present invention relates to a combined type that forms an optical pattern and a magnetic pattern on the rotating disk plate.

  Conventionally, as such a composite rotary encoder, for example, in JP-A-01-305314, an optical pattern and a magnetic pattern are formed on a rotating disk plate connected to a detected shaft, and the absolute angle is set by the optical pattern. A method for detecting one rotation of a rotating disk plate with a magnetic pattern is disclosed. In the same document, the optical pattern is composed of a pattern that outputs an absolute signal and a pattern that outputs an incremental signal, and the rotation angle is roughly detected by the absolute signal, and the finer rotation angle is detected by the incremental signal. I have to.

Therefore, in such a rotary encoder, it is necessary to detect the reference position of the rotating disk plate. In this document, an N-S facing magnet (magnet film) is attached to the rotating disk plate in an annular shape. Thus, when detecting the reference position of the rotating disk plate and detecting the amount of rotation at the time of a power failure or the like, or detecting the origin position of the rotating disk plate, a magnetic pattern is applied to the rotating disk plate and this is used as a magnetic detecting element. The feature is that the power consumption of the device can be reduced by detecting with.
Japanese Patent Laid-Open No. 01-305314

  As described above, when an optical pattern and a magnetic pattern are formed on a rotating disk plate, and this is detected by a photoelectric conversion element and a magnetic detection element, conventionally, the rotating disk plate is sandwiched between the rotating disk plate as described in Patent Document 1 above. A substrate on which the light receiving element is mounted is disposed on the other side, and a substrate on which the magnetic detection element is mounted on the other side. For this reason, the substrate of the light receiving element and the substrate of the magnetic detection element must be aligned with respect to the pattern of the rotating disk plate and mounted at accurate positions. It must be constructed robustly so that it does not deviate.

  In addition, the substrate on which the light receiving element is mounted is divided into a main substrate and a sub substrate, and a processing circuit for converting a detected value into a predetermined output format or waveform shaping is mounted on the main substrate. It is also known to employ a configuration in which the separated sub-board is fixed by soldering or the like, and to mount the light receiving element of this sub-board. However, in either case, the light receiving element and the magnetic detection element are positioned while being vertically separated from each other about the axis of the rotating disk plate, while aligning the light receiving element on one side and the magnetic detection element on the other side with a jig or the like, respectively. It is arranged at a predetermined position above. In particular, the adjustment of the positions of the light receiving element and the magnetic detection element with respect to the pattern on the rotating disk plate in the assembly work requires experience and complicated work.

  Therefore, in the present invention, in the substrate configuration in which the main substrate arranged at an accurate position with respect to the rotating disk plate and the sub substrate bonded to the main substrate are separated, the light receiving element and the magnetic detection element are fixed to the sub substrate, The main problem is to provide a rotary encoder in which the position adjustment of the light receiving element and the magnetic detection element can be easily performed and easily assembled by joining the sub board to the main board.

  In order to achieve the above-described problems, the present invention employs the following configuration. A rotating disk plate connected to the detected shaft and rotating integrally, a light transmitting slit formed in the rotating disk plate, a light source opposed to the light transmitting slit, and a light receiving element for photoelectrically converting light from the light source A rotary encoder is composed of a magnetic body (magnetic pattern forming means; hereinafter the same) disposed on the rotating disk plate and at least one magnetic detection element disposed at a position facing the magnetic body.

  The light source is fixedly disposed on a spindle base that rotatably supports the rotating disk plate, and a substrate having an output signal processing circuit is disposed on the opposite side of the rotating disk plate. Then, a sub-board on which the light receiving element is mounted is provided on the board, and the magnetic detection element is integrally attached to the sub-board. With this configuration, the light receiving element and the magnetic detection element are attached to the sub-board, and if the sub-board is adjusted with a positioning marker, for example, and joined to the main board, both elements can be incorporated at the correct positions. I can do it.

  The translucent slit comprises a plurality of slits that form different patterns for each angular position, and the output signal processing circuit comprises a position signal generation circuit that outputs an absolute signal in binary form to constitute an absolute encoder. I can do it. Further, the rotation direction of the rotating disk plate can be detected by disposing the second magnetic detection element on the magnetic pattern forming means opposite to the substrate at a position having a predetermined angle phase different from that of the sensor. In addition, it is possible to appropriately combine Hall elements or magnetoresistive elements, such as the first magnetic detecting element being a Hall element and the second magnetic detecting element being a magnetoresistive element.

  The present invention is a substrate configuration in which a main substrate arranged at an accurate position with respect to a rotating disk plate and a sub substrate bonded to the main substrate are separated, and a light receiving element and a magnetic detection element are fixed to the sub substrate, By joining this sub-board to the main board, it is easy to adjust the position of the light-receiving element and the magnetic detection element. In the past, the light-receiving element and the magnetic detection element were individually positioned and fixed on the rotating disk plate. In comparison, since both the elements are positioned at the same time and fixed at a predetermined position on the rotating disk plate, assembly is easy and inexpensive.

  Hereinafter, the present invention will be described in detail based on the preferred embodiments shown in the drawings. FIG. 1 is a conceptual diagram showing the principle configuration of a rotary encoder, and FIG. 2 is a cross-sectional view showing the relationship between the components. In general, a rotary encoder is provided with a rotating disk plate 13 as shown in FIG. 1, and a plurality of optical patterns 131 are provided in the rotating direction of the rotating disk plate 13. The light source (light emitting element) 17 and the light receiving element 14 are arranged to face each other with the optical pattern 131 interposed therebetween, and the output value from the light receiving element 14 is shaped and output to the outside.

  The optical pattern 131 includes a plurality of light-transmitting slits arranged at predetermined intervals on a track in the rotation direction, the light passing through each light-transmitting slit is detected by the light receiving element 14, and the output signal is cumulatively added to the angular position. Incremental type for detecting the light, or an absolute type for forming a light-transmitting slit having a different shape pattern on the track, outputting a signal corresponding to the rotation angle from the light receiving element 14, and detecting the absolute angular position by this detection signal Configure. Further, a composite type having both of these is known.

  In addition, it is necessary to detect the starting point of rotation simultaneously with the angular position of the rotary disk plate 13 and output it as an origin signal. This origin signal resets the cumulative counter in the case of the incremental type, and in the case of the absolute type Used for control such as correcting the angular position. As the position pattern for detecting the origin position, an optical translucent slit or a magnetic magnetic pattern is used. In the illustrated example, a magnetic pattern 132 is formed on the rotating disk plate 13, and this magnetic pattern 132 is detected by the magnetic detection element 15 to output an origin signal.

  By detecting the pattern magnetically in this way, it becomes possible to detect the rotational speed of the rotating disk plate 13 with a weak power source such as a battery power source when an abnormality occurs in the power supply such as a power failure. The origin signal shown in the figure forms a magnetic pattern 132 by adhering and integrating a magnetic body (magnetic pattern forming means) such as a magnet sheet to the rotating disk plate 13.

  Then, the magnetic position is detected by the magnetic detection element 15 disposed opposite to the magnetic pattern 132 with a small gap. As the magnetic detection element 15, a Hall element, a magnetoresistive element (MR element), and the like are known, and these magnetic detection elements can be used in the present invention.

  On the other hand, a light source (light emitting element) 17 is disposed on one side and a light receiving element 14 is disposed on the other side of the optical pattern 131 with the light transmitting slit interposed therebetween. The light source (light emitting element) 17 is, for example, an LED light emitting element. Consists of photodiodes. The output of the light receiving element 14 such as a photodiode is output to the outside as, for example, a binary code from a code signal conversion circuit.

  Next, the relationship between the above-described configurations will be described with reference to FIGS. A spindle base 110 constituting the apparatus frame, a rotating shaft 12, a rotating disk plate 13, a circuit board 140, and a casing 150 are included. The spindle base 110 is made of an aluminum alloy or other metal that has an appropriate shape such as a columnar shape or a polygonal cylindrical shape, and is firmly formed of an aluminum alloy or other metal. The shaft 12 is rotatably supported. The rotating shaft 12 is connected to a detected end shaft (not shown) and a coupling joint at the base end, and a hub 121 is provided at the shaft end. The hub 121 has a flat surface orthogonal to the rotating shaft 12. The rotating disk plate 13 is joined to this surface.

  Further, the rotary shaft 12 is provided with a step for engaging with the inner racer of the bearing, and the shaft end is provided with a D-cut for fitting a joint connected to a detected shaft (not shown). Based on this D-cut, the detection start position (angular position) of the detected shaft is aligned with the origin position of the rotary disk plate 13 attached to the rotary shaft 12. Therefore, the rotary disk plate 13 described above is fixed to the hub 121 of the rotary shaft 12 and is adjusted and attached with an adhesive or the like so that the center of the rotary shaft and the rotation center of the optical pattern 131 coincide with each other by a method described later.

  The light receiving element 14 and the light source (light emitting element) 17 are attached to the spindle base 110 through the rotating disk plate 13 as follows. First, the light receiving element 14 is constituted by a photoelectric conversion element, and is assembled in a sub-board 142, and this sub-board 142 is attached to a circuit board 140 as a main board by soldering or the like. Therefore, in the present invention, the magnetic detection element 15 is integrally attached to the sub-substrate 142 via the spacer 21. The circuit board 140 incorporates an amplification circuit that amplifies the detection value of the light receiving element 14 and a waveform generation circuit that converts the detection value into an output waveform. The circuit board 140 is fixed to a stem 113 provided on the spindle base 110 with screws. The illustrated stem 113 is provided at about three places around the rotary shaft 12 and fixes the circuit board 140 so that the position thereof can be adjusted by a method described later.

  On the other hand, the light source (light emitting element) 17 has a light source lamp such as an LED attached to the spindle base 110 as follows. First, the spindle base 110 is divided into an upper base 110a and a lower base 110b in the vertical direction of the rotary shaft 12. The upper base 110a is made of a strong material such as an aluminum alloy, and the lower base 110b is rich in workability such as a synthetic resin. It is made up of materials. The above-described shaft hole is formed in the upper base 110a, and the above-described rotating shaft 12 is supported by bearing in this shaft hole. The upper base 110 a is provided with an axial through hole 114, and the light emitting element 17 is attached to the through hole 114. Further, a fixed slit plate 16 is attached to the upper base 110a so as to cover the through hole 114.

  The lower base 110b has a shaft hole 115 for fitting the rotating shaft 12 at the center and a seal mounting groove 118 on the outer periphery. The lower base 110b is formed by synthetic resin molding, and a sealing member 116 is integrally formed in the shaft hole 115 by insert molding. That is, the lower base 110b closes the through hole 114 of the upper base 110a and simultaneously seals the gap with the rotary shaft 12 by the sealing member 116. Thus, when the lower base 110b and the sealing member 116 are integrally formed, the assemblability is improved as compared with the case where the two are individually formed, and at the same time, the hermeticity is improved and dust does not enter from the outside.

  The lower base 110b configured as described above is fixed to the upper base 110a with screws (not shown), and both are integrated. An O-ring 119 is attached to the seal attachment groove 118 provided in the lower base 110b, and the casing 150 is fitted therein. The casing 150 is formed in a cap shape that covers the circuit board 140, the rotating disk plate 13, the fixed slit plate 16, and the light source (light emitting element) 17, and is fixed to the spindle base 110. FIG. 3 shows an external configuration of the rotary encoder according to the present invention, and FIG. 22 shows a bias magnet.

  In the rotary encoder having the above configuration, the present invention separates the circuit board 140 (main board) incorporating the output signal processing circuit and the sub board 142 on which the above-described light receiving element 14 is mounted. The light receiving element 14 is attached to the sub-substrate 142 so as to coincide with the center line (XX line in FIG. 4) directed to the rotation center of the rotary disk plate 13. That is, in the light receiving element 14, a plurality of light receiving elements are arranged in a predetermined direction (YY line in FIG. 5), and the sub-substrate 142 is circuitized so that the YY line and the XX line of the rotary disk plate 13 coincide. It is attached (bonded) to the substrate 140.

  Therefore, the illustrated magnetic detection element 15 is composed of an MR element, and is arranged to be tilted 45 degrees to the left and right around the magnetic pattern of the MR element. FIG. 4 shows an example in which a magnetic pattern A of plus 45 degrees and a magnetic pattern B of minus 45 degrees with respect to the center line XX of the rotating disk plate are formed. Thus, if the sub-substrate 142 is aligned and attached to the circuit board 140 by matching the magnetic pattern of the MR element with the arrangement reference line (Y-Y line) of the light-receiving element 14, the light-receiving element 14 and the magnetic detection element 15 are attached. Can be simultaneously aligned with the specified position.

The conceptual diagram which shows the principle structure of a rotary encoder (absolute type). It is sectional drawing which shows the structure of the rotary encoder concerning this invention, (a) shows the whole figure, (b) shows the principal part enlarged view of (a). The whole perspective view of a rotary encoder. Explanatory drawing which shows the structure of the light-receiving surface concerning this invention. The block diagram when a magnetic pattern is customized and a magnetic detection element (MR element) is arranged on a chip. When a conventional magnetic detection element (MR element) is arranged. The block diagram of the conventional light-receiving surface.

Explanation of symbols

13 Rotating disk plate 14 Light receiving element 15 Magnetic detecting element 16 Fixed slit plate 17 Light source (light emitting element)
110 Spindle base 131 Optical pattern 132 Magnetic body (magnetic pattern forming means)
140 Circuit board (main board)
142 Sub-board

Claims (5)

A rotating disk plate connected to the detected shaft and rotating integrally;
A translucent slit formed in the rotating disk;
A light source facing the light-transmitting slit and a light-receiving element that photoelectrically converts light from the light source;
Magnetic pattern forming means disposed on the rotating disk plate;
A rotary encoder in which at least one magnetic detection element is disposed at a position facing the magnetic pattern forming means,
The light source is fixedly disposed on a spindle base that rotatably supports the rotating disk plate, and a substrate having an output signal processing circuit is disposed on the opposite side of the rotating disk plate,
A rotary encoder comprising a sub-board on which the light receiving element is mounted on the board, and the magnetic detection element is integrally attached to the sub-board. The translucent slit includes a plurality of slits that form different patterns for each angular position, and the output signal processing circuit includes a position signal generation circuit that outputs an absolute signal in a binary format. The rotary encoder according to 1. A second magnetic detecting element is disposed opposite to the magnetic pattern forming means, and the magnetic detecting element is disposed and fixed on the substrate at a position different from the first magnetic detecting element by a predetermined phase. The rotary encoder according to claim 1 or 2. 4. The rotary encoder according to claim 3, wherein the first magnetic detection element is a Hall element, and the second magnetic detection element is a magnetoresistive element. 5. The rotary encoder according to claim 1, wherein the magnetic detection element is bonded and fixed to the sub-board through a spacer.

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