JP2010271174A - Encoder - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an encoder for keeping the number of components reduced. <P>SOLUTION: The encoder includes: a rotary section formed by a rotating member, where at least one of magnetic and optical patterns is formed, and a single member; and a detection section for detecting at least one of a magnetic field by the magnetic pattern, and the optical pattern. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an encoder.

  An encoder is known as a device that detects the number of rotations and rotation angle of a rotating body such as a rotating shaft of a motor (Patent Document 1). For example, the encoder is used by being attached to a rotating shaft of a motor. As a specific configuration of the encoder, for example, a rotating portion on which a predetermined light reflection pattern and a magnetic pattern are formed is rotated integrally with a rotation shaft, and for example, the light reflection pattern is irradiated with light to read reflected light. By detecting the change in the magnetic pattern, the number of rotations of the rotating shaft of the motor can be detected.

  Such an encoder is formed by assembling parts of a mounting member (hub) attached to a rotating shaft of a motor, a disk member formed with a light reflection pattern, and a magnet member formed with a magnetic pattern.

JP 2004-20548 A

  However, the above configuration has a problem that the number of parts increases, and the process of assembling these parts becomes complicated.

  In view of the circumstances as described above, an object of the present invention is to provide an encoder capable of reducing the number of parts.

  An encoder according to the present invention includes a rotating member formed of at least one of a magnetic pattern and an optical pattern, a rotating unit formed of a single member, and a detection unit that detects a magnetic field and the optical pattern by the magnetic pattern. It is characterized by providing.

  According to the present invention, the number of parts can be reduced.

1 is a cross-sectional view showing a configuration of an encoder according to a first embodiment of the present invention. The top view which shows the structure of the encoder which concerns on this embodiment. FIG. 3 is a cross-sectional view showing a partial configuration of an encoder according to the present embodiment. Sectional drawing which shows the structure of the encoder which concerns on 2nd Embodiment of this invention.

[First Embodiment]
Hereinafter, a first embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a cross-sectional view showing the configuration of the encoder EC.
As shown in FIG. 1, the encoder EC is a device that detects the number of rotations of a rotating body such as a motor. The encoder EC has a rotating part R and a detection mechanism (detection part) D. The encoder EC is used in a state in which the rotating part R is disposed to face the detection mechanism D. FIG. 2 is a plan view showing the configuration of the rotating part R of the encoder EC. Hereinafter, the configuration of the encoder EC will be described with reference to FIGS. 1 and 2.

  The rotating portion R is fixed to a rotating shaft 40 of a motor MTR that is a rotating body and rotates integrally with the rotating shaft 40. The rotating portion R has a configuration in which almost the entire surface of the rotating member 10 formed into a disk shape using, for example, SUS, which is a magnetic material, is covered with a non-reflective layer 11 such as black nickel or black alumite. The surface of the rotating member 10 is formed in a mirror shape so as to reflect light having a predetermined wavelength.

The rotating part R has a mounting part 20 and a pattern forming part 21.
The attachment portion 20 is formed such that the lower surface 10b side of the rotating member 10 protrudes in an annular shape. An insertion hole 20 a is formed in the attachment portion 20. The insertion hole 20a is a portion into which the rotating shaft 40 of the motor MTR is inserted. The mounting portion 20 has a fixing mechanism (not shown) that fixes the rotating shaft 40 and the mounting portion 20.

  The pattern forming unit 21 is provided on the upper surface 10 a of the rotating member 10. A light reflection pattern 24 and a magnetic pattern 25 are formed on the pattern forming unit 21. The light reflection pattern 24 is formed in an annular shape along the outer periphery of the rotating portion R, for example. The light reflection pattern 24 has a light transmission layer 24a. The light transmission layer 24a is formed using, for example, SU-8 resist or the like, and is a portion that transmits light of a predetermined wavelength. The light transmission layer 24a is formed on the surface of the rotating member 10 formed in a mirror shape.

FIG. 3 is a cross-sectional view showing the configuration of the upper surface 10a of the rotating member 10.
As shown in FIG. 3, the non-reflective layer 11 is not formed in the region where the light transmission layer 24a is formed, and the surface of the rotating member 10 is exposed on the rotating portion R through the light transmission layer 24a. It is in a state. For this reason, out of the light L directed to the upper surface of the rotating part R, the light L applied to the non-reflective layer 11 is absorbed by the non-reflective layer 11. Further, the light L applied to the light transmission layer 24 a is transmitted through the light transmission layer 24 a and reflected by the surface of the rotating member 10.

  Returning to FIGS. 1 and 2, the magnetic pattern 25 is formed in an annular shape on the inner peripheral side of the light reflecting pattern 24 in the rotating portion R, for example. For example, as shown in FIG. 2, the magnetic pattern 25 is partitioned into an inner peripheral portion and an outer peripheral portion of the ring. In the inner periphery of the ring, the N pole is magnetized in the half region (the region on the right side in the drawing) of the ring as viewed in the axial direction of the rotating shaft 40, and the other half region (in the drawing). The left region is magnetized to the south pole. At the outer periphery of the ring, the S pole is magnetized in a half region (the right region in the drawing) of the ring as viewed in the axial direction of the rotating shaft 40, and the other half region (the left side in the drawing). Are magnetized in the N pole.

  Thus, the rotation part R has a configuration in which both the light reflection pattern 24 and the magnetic pattern 25 are formed on the rotation member 10 as one member. The light reflection pattern 24 and the magnetic pattern 25 are formed on the same surface of the rotating member 10.

The detection mechanism D is a part that detects the magnetic field generated by the light reflection pattern 24 and the magnet member M. The detection mechanism D includes a housing 30, an optical sensor 31, and a magnetic sensor 32.
The housing | casing 30 is formed in the cup shape of planar view circular shape, for example. The housing 30 is fixed to the motor MTR and is not fixed to the rotating shaft 40. Therefore, even if the rotating shaft 40 rotates, the relative position between the housing 30 and the motor MR does not change.

  The optical sensor 31 is a sensor that detects the light reflection pattern 24 by emitting light toward the light reflection pattern 24 and reading the reflected light via the light reflection pattern 24. The optical sensor 31 is attached to the inner surface of the housing 30. The optical sensor 31 is disposed, for example, at a position overlapping the light reflection pattern 24 of the rotating portion R when viewed in the axial direction of the rotating shaft 40.

  The optical sensor 31 includes a light emitting unit that emits light and a light receiving unit that receives reflected light. For example, an LED or the like is used as the light emitting unit. As the light receiving unit, for example, a photoelectric element or the like is used. The light read by the light receiving unit is transmitted as an electric signal to a control device (not shown). Each part constituting the optical sensor 31 is held by the housing 30.

  For example, a pair of magnetic sensors 32 are arranged at positions overlapping the magnet member M when viewed in the axial direction of the rotary shaft 40 (magnetic sensors 32A and 32B). Each magnetic sensor 32A and 32B has a bias magnet (not shown) and a magnetoresistive element (not shown). The magnetic sensors 32A and 32B are respectively held on the inner surface of the housing 30.

  The bias magnet is a magnet that forms a combined magnetic field with the magnetic field of the magnet member M. As a material constituting the bias magnet, for example, a rare earth magnet having a large magnetic force such as samarium / cobalt can be cited. The bias magnet is disposed at a position where it does not contact or adjoin the magnetoresistive element.

  The magnetoresistive element has two orthogonal repeating patterns formed by, for example, metal wiring. In the magnetoresistive element, the electric resistance decreases when the direction of the magnetic field is close to the direction perpendicular to the direction of the current flowing in the repetitive pattern. The magnetoresistive element converts the direction of the magnetic field into an electric signal by utilizing the decrease in electric resistance. The magnetoresistive element is adapted to detect a combined magnetic field generated by the magnetic field of the magnet member M and the magnetic field of the bias magnet. The detection result is transmitted as an electric signal to the control device (not shown).

  The encoder EC is provided with a control device (not shown). The control device controls the operation of the light emitting unit of the optical sensor 31 and obtains the rotation angle of the rotary shaft 40 based on the output from the light receiving unit of the optical sensor 31. Moreover, this control apparatus performs the process which calculates | requires the rotation speed of the rotating shaft 40 based on the output from magnetic sensor 32A and 32B.

Next, the formation process of the rotating part R of the encoder EC configured as described above will be described.
When forming the rotating portion R, first, the rotating member 10 is molded into a predetermined shape, and the upper surface 10a of the molded rotating member 10 is polished into a mirror shape. After polishing the upper surface 10a, a pattern of the light transmission layer 24a is formed in an annular region along the peripheral edge of the upper surface 10a by using a film forming method such as a photolithography method.

  After the pattern of the light transmission layer 24a is formed, the rotating member 10 is immersed in a plating tank, and the non-reflective layer 11 is formed on the surface of the rotating member 10 by a plating method. At this time, since no current flows in the region of the upper surface 10a where the light transmission layer 24a is formed in the rotating member 10, the non-reflective layer 11 is not formed. Thus, the light reflection pattern 24 is formed on the upper surface 10a of the rotating member 10.

After the non-reflective layer 11 is formed, a region surrounded by the light reflection pattern 24 on the upper surface 10a of the rotating member 10 is magnetized into a predetermined pattern. Since the non-reflective layer 11 is formed on the upper surface 10a, the magnetized portion is magnetized to form the magnetic pattern 25. Thus, the magnetic pattern 25 is formed without using a magnet member.
As described above, the rotating portion R is formed.

Next, the operation of the encoder EC configured as described above will be described.
When the rotating shaft 40 of the motor MTR rotates, the rotating portion R attached to the rotating shaft 40 rotates integrally with the rotating shaft 40. Since the detection mechanism D fixed to the motor MTR is not connected to the rotating shaft 40, it is in a stationary state without rotating.

  When the rotating part R rotates, the light reflection pattern 24 formed on the rotating part R moves in the rotating direction. The control device detects the movement angle of the light reflection pattern 24 by emitting light to the light reflection pattern 24 using the optical sensor 31 and reading the reflected light.

  As the rotating part R rotates, the magnetic pattern 25 formed on the rotating part R also moves in the rotating direction. As the magnetic pattern 25 moves, the combined magnetic field of the first magnetic field formed by the magnetic pattern 25 and the second magnetic field of the bias magnet changes periodically. The control device detects the number of rotations of the magnet member M (rotating shaft) by using the magnetic sensors 32A and 32B to detect the period of change of the combined magnetic field.

  As described above, according to the present embodiment, the rotating part R is formed of the rotating member 10 on which the magnetic pattern 25 and the optical pattern 24 are formed and a single member. Can be reduced. Thereby, the number of parts of the encoder EC can be reduced.

[Second Embodiment]
Next, a second embodiment of the present invention will be described. In the present embodiment, the same or equivalent components as those in the first embodiment are denoted by the same reference numerals, and description thereof is omitted or simplified. In this embodiment, since the structure of the rotation part R differs from 1st Embodiment, it demonstrates centering on the said difference.

FIG. 4 is a cross-sectional view showing the configuration of the encoder EC2 according to this embodiment.
As shown in FIG. 4, the rotating part R2 of the encoder EC2 includes a rotating member 50 formed using a magnetic material (eg, SUS, iron, magnet). In the rotation part R2, the non-reflective layer is not formed on the surface of the rotation member 50. The lower surface 50b side of the rotating member 50 protrudes in an annular shape. The rotating shaft 40 is attached to the protruding portion. The rotating member 50 is molded in such a shape that the lower surface 50b side protrudes in this way.

  The rotating member 50 has a light reflection pattern 54 and a magnetic pattern 55 on the upper surface 50a. The light reflection pattern 54 has a light reflection layer 54a. The light reflecting layer 54a is formed using a material such as metal that reflects light of a predetermined wavelength. The light applied to the light reflecting layer 54a is reflected on the surface of the light reflecting layer 54a. In order to ensure high light reflectivity, for example, the upper surface of the light reflection layer 54a is preferably formed in a mirror shape.

  The magnetic pattern 55 is formed in an annular shape on the inner peripheral side of the light reflecting pattern 54. The magnetic pattern 55 is formed by magnetizing a part of the rotating member 50 including a magnetic material. The magnetic pattern 55 can be formed in the same pattern as the magnetic pattern 25 of the first embodiment, for example.

  By forming the rotating member 50 as a single member using a magnetic material as in this embodiment, the rotating member 50 can be easily formed at low cost.

The technical scope of the present invention is not limited to the above-described embodiment, and appropriate modifications can be made without departing from the spirit of the present invention.
For example, in the above embodiment, the configuration in which both the light reflection pattern and the magnetic pattern are formed on the rotating member as a single member has been described, but the present invention is not limited to this. For example, only one of the light reflection pattern and the magnetic pattern may be formed.

  Moreover, although the said embodiment demonstrated the structure which uses SUS (1st Embodiment) and a magnetic body (2nd Embodiment), for example as a constituent material of the rotating member which comprises the rotation part R, it is restricted to this. There is no. For example, a magnet may be used as the rotating member. Compared with the case where a magnetized pattern is formed on a magnetic material, when a magnet is used as a rotating member, a strong magnetic pattern is formed over the entire rotating member. Thereby, it is possible to easily detect magnetism by the magnetic sensor 32 (32A, 32B). Further, since the step of magnetizing can be omitted, the number of steps can be reduced.

  In the first embodiment, the configuration of the rotating portion R has been described as a configuration in which the region outside the light transmitting layer 24a on the surface of the rotating member 10 is covered with the non-reflective layer 11, but is not limited thereto. For example, the entire surface of the rotating member 10 may be covered with the non-reflective layer 11, and the light reflecting pattern 24 may be formed by forming the light reflecting layer on the non-reflective layer 11. . When a light reflecting layer is formed on the non-reflective layer 11, a light transmitting layer may be further formed on the light reflecting layer. Thereby, the light reflection layer is protected.

  In the above embodiment, the configuration in which the upper surface 10a of the rotating member 10 and the upper surface 50a of the rotating member 50 are formed flat has been described as an example, but the present invention is not limited thereto. For example, a configuration in which a step or unevenness is formed on the upper surface 10a or the upper surface 50a may be used. Specifically, a step may be formed between the formation region of the light reflection pattern 24 and the formation region of the magnetic pattern 25. Moreover, in the said embodiment, not only the light reflection pattern 24 but a light transmissive pattern may be sufficient.

  EC, EC2 ... Encoder R, R2 ... Rotating part D ... Detection mechanism (detecting part) 10, 50 ... Rotating member 11 ... Non-reflective layer 20 ... Mounting part 24, 54 ... Light reflecting pattern (optical pattern) 24a ... Light transmitting layer 25, 55 ... Magnetic pattern 31 ... Optical sensor 32 (32A, 32B) ... Magnetic sensor

Claims (11)

A rotating member formed of at least one of a magnetic pattern and an optical pattern, and a rotating part formed of a single member;
An encoder comprising: a detection unit configured to detect at least one of a magnetic field generated by the magnetic pattern and the optical pattern. The encoder according to claim 1, wherein the rotating member has an attachment portion that is attached to a rotating shaft of an object. The encoder according to claim 1, wherein the rotating member is formed using a magnetic material. The encoder according to any one of claims 1 to 3, wherein the magnetic pattern is a pattern magnetized on the rotating member. The encoder according to any one of claims 1 to 4, wherein the optical pattern is a pattern of a light reflecting portion. The rotating member has a surface covered with a non-reflective layer,
The encoder according to claim 5, wherein the light reflecting portion is formed on the non-reflecting layer. The rotating member has a light reflection layer whose surface is mirror-finished and a non-reflection layer that covers the light reflection layer,
The encoder according to claim 5, wherein the light reflecting portion includes a light transmitting portion that penetrates the non-reflecting layer. The encoder according to claim 6 or 7, wherein the non-reflective layer is provided on the entire surface of the rotating member. The encoder according to any one of claims 6 to 8, wherein the non-reflective layer includes black nickel or black alumite. The encoder according to any one of claims 1 to 9, wherein the magnetic pattern and the optical pattern are provided on the same surface of the rotating member. The encoder according to claim 1, wherein a magnet is used as the rotating member.

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