JP2008107123A - Optical rotary encoder - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical rotary encoder having a light-weight and compact whole body, and easy maintenance, by integrating a metal rotary disk which is not broken, while securing the structural whole strength. <P>SOLUTION: In this optical rotary encoder 11 formed by arranging a fixed slit plate 32 equipped with a fixing side slit 34 and a rotary disk 42 equipped with a rotation side slit 44 between a light emitting element and a light receiving element in a housing 12, at least the rotary disk 42 is formed by using a metal foil as a base material, and by arraying each rotation side slit 32 in each phase as a row of a plurality of discontinuous circular rotation side short holes 45 bored so that continuous reception of light from the light emitting element by the light receiving element becomes possible in the circular plane direction. Hereby, the structural strength is given to the encoder 11. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a rotating disk in which rotation-side slits as code patterns extending over multiple phases are formed separately for each phase in the circumferential plane direction with the same rotation center axis, and a positional relationship facing each rotation-side slit individually. Of the fixed slit plate with fixed side slits formed for each phase, at least the rotating disk is not a heavy and fragile glass base material, but is based on a metal flake that is hard to break and lightweight and compact This is a technology related to an optical rotary encoder that is formed while maintaining structural strength among materials.

  An optical rotary encoder used to attach to a rotating shaft body including a motor shaft and detect its rotation angle, etc. is a light emitting element, a rotating disk formed with a rotating slit as a code pattern, and a fixed A fixed slit plate having side slits and a light receiving element that receives light from the light emitting element are generally formed as main constituent members.

  FIGS. 12 to 14 are explanatory views showing specific structural examples of conventional optical rotary encoders, in which FIG. 12 is an exploded perspective view of the whole, and FIG. FIG. 14 shows a plan view of the rotating disk portion and an enlarged view of a main part thereof, respectively.

  According to these drawings, the optical rotary encoder 101 as a whole is provided with a rotating cylinder 103 that is connected to a rotating shaft of a motor (not shown) and rotates in the center, and an index that includes a fixed slit plate 105 on the periphery thereof. A housing 102 in which the unit 104 is fixed, and a rotating disk 115 which is provided with a rotating side slit 116 as a polyphase code pattern in the circumferential direction and is integrally connected to the rotating cylinder portion 103 side via a fixed washer 113. The rotating disk 115 and the cover 122 that covers the housing 102 side are formed.

  Among these, the fixed slit plate 105 constituting the index unit 104 is a transparent window formed by removing the light shielding layer on the transparent glass substrate covered with the light shielding layer 106 by, for example, an etching technique (masking or the like). A predetermined fixed side slit 106 is provided.

  Further, the rotating disk 115 includes a rotation-side slit 117 as a translucent window formed by removing the light shielding layer 116 by an etching method (masking or the like) on the transparent glass substrate covered with the light shielding layer 116. For example, the position signal of the rotor magnetic pole of the brushless motor can be detected through the rotation-side slit 117 to control the rotation thereof. In this case, the rotating disk 115 needs to reduce the slit width of the rotation-side slit 117 as the number of divisions per circle (the number of divisions of the slit holes) increases, so that transmission through the rotation-side slit 117 is performed. The amount of light also tends to decrease.

  Further, the index unit 104 is positioned in the housing 102 after accurately aligning the position of the fixed side slit 106 of the fixed slit plate 105 with the position of the rotating side slit 117 in the corresponding positional relationship on the rotating disk 115. Must be fixed and stationary.

  Further, the Z-phase as a position signal output once per rotation removes the light-shielding layer on the outer peripheral edge side of the rotating disk 115 to form a light-transmitting surface, and leaves the light-shielding layer in a part of the light-shielding window. 118, which can be detected through the light shielding window 118.

  However, the optical rotary encoder 101 of the conventional type shown in FIGS. 12 to 14 is weak against vibration and dropping because both the fixed slit plate 105 and the rotating disk 115 are formed using a glass substrate. The kind of glass that can be used is also limited because it is easily broken. In addition, the rotating disk 115 itself is fragile and needs to be thickened. As a result, the overall weight of the rotating disk 115 increases and the size of the rotating disk 115 increases. Inconveniences such as reduction are generated, and management and maintenance are complicated.

  Further, the fact that the rotating disk 115 itself is heavy has a problem that the moment of inertia works and the response controllability deteriorates.

  Further, the index unit 104 accurately aligns the position of the fixed slit 107 of the fixed slit plate 105 with the position of the rotating slit 117 in the corresponding positional relationship on the rotating disk 115 side, and then moves the index unit 104 to the housing 102 side. The position must be fixed, and there is also a complicated work such as the need for a dedicated jig for that purpose.

On the other hand, Patent Document 1 below discloses a technique that can eliminate an assembling work by forming a disk of a code plate and an attachment portion as an integrally molded product made of plastic. In this case, when the fitting portion of the shaft member is press-fitted into the fitting hole, the centering holding portion is plastically deformed so that centering can be realized.
Japanese Patent Laid-Open No. 11-14404

  In addition, the above-mentioned Patent Document 1 discloses a conventional technique in which a rotating disk is formed using a thin metal plate having excellent mechanical strength instead of the glass substrate that is easily broken as shown in FIG. Yes. The rotating disk in this case is composed of three members as disclosed in FIG.

  That is, the rotating disk as a conventional example shown in FIG. 3B in the above-mentioned Patent Document 1 is made by a washer after a metal disk body is overlaid on a collar part provided in a metal hub part. It is formed by reinforcing locking. In this case, the metal disk body has a code element (lattice pattern of a transmission part and a light-shielding part) formed on the peripheral surface area near the outer periphery by metal etching or the like.

  However, there is a description that the rotating disk shown in FIG. 3B in Patent Document 1 has code elements (lattice patterns of a transmission part and a light shielding part) formed on a metal disk body. However, there is no specific disclosure regarding a specific configuration of the code element and a method of forming the code element.

  For this reason, when trying to form the metal disk body in the above-mentioned Patent Document 1 equivalent to, for example, the rotation side slit 117 as the light transmission window shown in FIG. It is not clear whether is adopted. If the rotation side slit is continuously formed in an arc shape like the rotation side slit 117 shown in FIG. 12 to generate a drive signal for the brushless motor, the disk body itself is an opaque metal. Therefore, it is necessary to form a long hole in an arc shape by removing the opaque portion by metal etching.

  However, when the rotation-side slit is continuously extracted from the metal disk body in Patent Document 1 in the same manner as the rotation-side slit 117 shown in FIG. 12, and is formed as a long hole as shown in FIG. Although a waveform signal (light intensity signal) as shown in FIG. 16A is obtained, there is a problem in that the overall strength is structurally lowered by the extracted amount, and bending and distortion are likely to occur.

On the other hand, when the rotation side slits are arranged at equal intervals in the metal disk body as shown in FIG. 15 (b) in order to avoid structural strength reduction, between the rotation side slits. The secured light receiving area is not constant. Therefore, there is a 16 inconvenience not be obtained only pulsed discontinuous waveform signal P ₂ are different discontinuous waveform signal (light intensity signal) as in (a) as shown in FIG. 16 (b) .

That is, when a rotation side slit is formed in a metal disk body as a row of extraction holes, and a continuous signal P ₁ having a waveform signal (light intensity) equivalent to that shown in FIG. FIG. 15 (c) shows a positional relationship as shown in FIG. 15 (c) with respect to the fixed slit side of the rotation side slit formed as a row of extraction holes, with a waveform signal (light intensity signal) as shown in FIG. 16 (c). there continuous waveform signal P ₁ has reached the face challenges of the need to sequence to devise so as to obtain.

  In view of the above-mentioned problems seen in conventional optical rotary encoders, the present invention is continuous that is equivalent to that obtained from a rotation-side slit using a conventional glass substrate while ensuring the overall structural strength. By making it possible to obtain a typical waveform signal from a metal rotating disk, not only does it break, but it is structurally strong and light and compact as a whole, and management and maintenance work is simplified. An object of the present invention is to provide an optical rotary encoder that can simultaneously realize the above.

  The present invention has been made in order to achieve the above object, and the rotation side slits as code patterns extending over multiple phases are concentric with different radii, and are formed for each phase in the circular plane direction of the light shielding surface. A rotating slit disk, and a stationary slit plate having stationary slits formed on each light-shielding surface for each phase under a positional relationship that individually faces the respective rotational side slits, and a light emitting element in the housing In an optical rotary encoder that is disposed between a light receiving element that receives light from the light emitting element, at least the rotating disk has a metal flake as a base material, and each of the rotating side slits in a circular plane direction. By arranging the light from the light emitting element by each phase as a row of a plurality of discontinuous arcuate rotation side short holes that are freely drilled for continuous light reception by the light receiving element. Degrees to retain the most important feature that formed.

  In this case, the fixed slit plate is formed by arranging a thin piece of metal as a base material and arranging the fixed side slit as one arcuate fixed side short hole drilled for each phase. The arc-shaped rotation side short holes and the arc-shaped fixed side short holes are arranged such that light from the light emitting element always reaches the light receiving element with a substantially constant light receiving area when the rotating disk rotates. It is preferable to arrange under the arrangement relationship.

  Further, the fixed side through hole formed in the light shielding surface of the fixed slit plate and the fixed side through hole projecting in the same plane direction from the outer peripheral edge of the rotating disk can freely face each other. The rotation direction and the number of rotations of the rotating disk may be freely formed between the rotation-side through hole formed in the light shielding surface.

  The rotating disk further includes an insertion hole for mounting on a rotating cylinder that is rotatably disposed in the housing, and a pressure contact with elasticity of the rotating cylinder is provided at a hole edge of the insertion hole. It is also possible to project a plurality of tongue pieces that are freely adjustable.

  According to the first aspect of the present invention, the rotation-side slit is formed by disposing a plurality of discontinuous arc-shaped rotation-side short holes drilled for each phase in the respective circumferential plane directions so that continuous light reception by the light-receiving element is possible. Unlike a case where a rotating disk is formed using a glass base material, the rotation is performed not only with light weight and not cracking but also with structural strength while using a metal flake as a base material. A disk can be formed.

  According to the second aspect of the present invention, the arc-shaped fixed side short holes and the arc-shaped rotation side short hole rows for each phase are such that the light from the light emitting element is always substantially constant with respect to the light receiving element when the rotating disk rotates. Waveform similar to the flicker-free waveform signal (light intensity signal) obtained from the rotation-side slit of a rotating disk made of a glass substrate. A signal (light intensity signal) can be obtained.

  According to the third aspect of the present invention, the fixed side through hole formed in the light shielding surface of the fixed slit plate and the fixed side through hole projecting from the outer peripheral edge of the rotating disk in the same plane direction. The direction of rotation and the number of rotations can be detected between the facing side and a rotation side through-hole formed in the light shielding surface. In addition, the surrounding blank area excluding the projecting piece on the rotating disk can be structurally used as a light-transmitting area equivalent to the slit pattern of the rotating disk made of a glass substrate.

  According to the fourth aspect of the present invention, since the plurality of tongue pieces that can be press-fitted with elasticity to the rotating cylinder body are projected from the hole edge of the insertion hole, the protruding piece is attached to the rotating cylinder. By making pressure contact with the body side, the rotating disk can be more reliably centered and disposed.

  1 is an exploded perspective view of an example of the present invention in which some of the components are omitted, FIG. 2 is a perspective view of a main part after assembly of the example shown in FIG. 1, and FIG. FIG. 4 is an enlarged explanatory view of the main part under the corresponding relationship with FIG. 3. Moreover, FIG. 5 shows the longitudinal cross-sectional view about the whole structure after an assembly.

  According to these figures, the optical rotary encoder 11 is provided with a rotating cylindrical body 14 connected to a rotating shaft of a motor (not shown) and rotated at the center, and a fixed slit plate 32 is disposed on the periphery thereof. A housing 12, a rotating disk 42 formed integrally with the rotating cylinder 14 by forming a rotating slit 44 as a multi-phase code pattern in the circumferential direction, and the rotating disk 42 can be detachably attached to the housing 12 side. And a cover 52 covering the surface.

  In this case, the housing 12 has a fixed slit plate 32 having fixed side slits 34 formed separately on the light shielding surface 33 in a positional relationship facing the rotation side slits 44 for each phase, and a radius. The rotating disk 42 having different concentric circles and having the rotation-side slits 44 formed in the circumferential direction of the light shielding surface 43 is positioned between the light emitting element 29 and the light receiving element 23. Originally arranged.

  Among these, the fixed slit plate 32 is, for example, a fixed side slit composed of a single arc-shaped fixed side short hole 35 drilled for each phase using a thin metal piece such as a stainless steel having a thickness of about 0.3 mm as a base material. 34 is provided. In this case, the fixed-side slit 34 including the arc-shaped fixed-side short hole 35 in FIG. 4 is formed as, for example, a three-phase (UVW phase) corresponding portion 36 for obtaining a drive signal of a brushless motor. The fixed slit plate 32 is also formed with a Z-phase (ABZ phase) corresponding portion 37 including a fixed-side through hole 38.

  The rotating disk 42 is formed in a circumferential direction for each phase in three phases (UVW phase) for obtaining a drive signal of, for example, a brushless motor using, for example, a thin metal piece such as a stainless steel having a thickness of about 0.3 mm as a base material. The rotation side slits 44 are arranged as a row of a plurality of discontinuous arcuate rotation side short holes 45 formed at equal intervals so as to maintain structural strength.

  That is, the rotating disk 42 has a row of arcuate rotation side short holes 45 arranged in pairs with the rotation angle shifted by 90 °, and the radius is different for each of the U-phase, V-phase, and W-phase which are three-phase AC currents. Different concentric circles are formed so that a rectangular wave output signal for one phase can be generated separately from each other.

  In addition, the rotation-side slit 44 for each phase, which is composed of a row of a plurality of discontinuous arc-shaped rotation-side short holes 45, is light from the light-emitting element 29 with respect to the fixed-side slit 34 that is formed of the arc-shaped fixed-side short holes 35. Can be formed based on an arrangement relationship in which the light receiving element 23 can continuously receive light.

  FIG. 6 is an explanatory diagram illustrating an example of an arrangement relationship between the arc-shaped fixed short holes 35 and the respective arc-shaped rotation-side short holes 45. According to the figure, the arcuate fixed side short hole 35 and each arcuate rotation side short hole 45 are formed with the same surface size that is confronted with each other. Further, the adjacent arcuate rotation side short holes 45, 45 completely overlap with the arcuate fixed side short hole 35 as shown in FIG. In the case where the face-matching region 55 is formed, one arcuate rotation side short hole 45 and two adjacent arcuate rotation side short holes 45 are shown in arcuate fixed side short holes 35 and (c) to (f). Are arranged with an interval at which two overlapping patterns can be generated in the case where the face-matching region 55 that partially overlaps is formed.

  FIG. 8 is an explanatory view showing a most preferable arrangement example between the arc-shaped fixed side short holes 35 and the respective arc-shaped rotation side short holes 45. According to the figure, each row of arc-shaped fixed short holes 35 and arc-shaped rotation-side short holes 45 for each phase forms a face-matching region 55 when the rotating disk 42 rotates, and the light from the light emitting element 29 is formed. Are arranged in such a manner that they always reach the light receiving element 23 under a substantially constant light receiving area.

  This will be described in more detail with reference to FIG. 10. The arrangement relationship between the arcuate fixed side short holes 35 and the respective arcuate rotation side short holes 45 is defined such that the length of the arcuate fixed side short holes 35 is p. If the length of the arcuate rotation side short hole 45 is p1 and the interval between two adjacent arcuate rotation side short holes 45, 45 is p2, the relation of p = p1 + p2 is established. Good. For example, the arc-shaped fixed side short holes 35 and the respective arc-shaped rotation side short holes 45 are arranged so that p1 = 9p / 10 and p2 = 1p / 20, whereby the light emitting element 29 is rotated when the rotating disk 42 is rotated. The light from the light can always reach the light receiving element 23 under a substantially constant light receiving area.

  The rotary disk 42 is formed with an insertion hole 46 for mounting on the rotary cylinder 14. A plurality of tongue pieces 47 are provided on the hole edge 46a side of the insertion hole 46 so as to be able to press contact with elasticity on the rotating cylinder 14 side. In this case, the application of the elastic force to each tongue piece 47 side is realized by individually forming through holes 48 having an arc shape inside each tongue piece 47.

  Further, a single projecting piece 49 is formed on the outer peripheral edge 42 a of the rotating disk 42 so as to protrude in the same plane direction. The light shielding surface 33 of the fixed slit plate 32 is formed on the light shielding surface 50 of the projecting piece 49. The rotation side through hole 51 is formed in correspondence with the fixed side through hole 38 formed as the ABZ phase corresponding part 37 formed in the inner side.

  That is, the fixed side through-hole 38 (37a) in the ABZ phase corresponding portion 37 transmits an original signal called a Z-signal between the rotation side through-hole 51 (51a) and the fixed side through-hole 38 (37c) An original signal called Z + is generated between the through hole 51 (51c) and a rectangular wave Z signal for detecting the rotational speed is obtained from these two original signals.

  Further, the fixed side through hole 38 (37b) in the ABZ phase corresponding portion 37 is composed of four slit groups arranged so that the phase difference 4 is different every 90 °, and the rotation side through hole 51 ( 51 b), a rectangular wave A signal and a rectangular wave B signal indicating the rotation direction can be obtained.

  The housing 12 in which the fixed slit plate 32 and the rotating disk 42 formed in this manner are arranged is formed of a metal material such as a stainless steel material having a substantially circular shape having a through hollow portion 13 at the center position thereof. .

  In addition, a rotating cylindrical body 14 having a flange portion 14 a is rotatably disposed through the through hollow portion 13 of the housing 12 via a bearing 25, and a rotating disk 42 is inserted into the rotating cylindrical body 14 through its insertion hole 46. It can come into contact with and support the flange portion 14a by being fed through.

  In addition, since the rotating disk 42 has a plurality of tongue pieces 47 projecting from the hole edge 46 a of the insertion hole 46 with elasticity, the rotating cylinder 14 is interposed through the tongue pieces 47. There is no backlash on the side, and it can be securely pressed.

  Further, the rotating disk 42 abutted and supported by the flange portion 14a can be driven by the rotation of the rotating cylinder 14 by being fixed to the flange portion 14a side by the screw member 16 with the fixed washer 15 interposed. So that the position is fixed.

  Further, the housing 12 includes a peripheral wall portion 17 standing smaller than the outer peripheral diameter thereof, and the peripheral end surface 53 is brought into contact with a stepped portion 17 a formed between the peripheral wall portion 17 and the housing 12. The cover 52 can be covered.

  In addition, a notch 18 is formed in the peripheral wall 17 of the housing 12, and a required circuit board 28 including a light emitting element 29 can be disposed through the notch 18 as shown in FIG. 5. It has become.

  A pair of positioning pins 21, 21 that can accurately place the fixed slit plate 32 at a position determined by the relationship with the rotating disk 42 are provided on the exposed surface 19 of the housing 12 surrounded by the peripheral wall portion 17. It is planted in the seating surface part 20 and can be arranged with the fixed slit plate 32 supported by the seating surface part 20 by inserting the guide holes 39 corresponding to the positioning pins 21 and 21 separately. .

  In addition, a recessed portion 22 is formed at an appropriate position of the seating surface portion 20 in the seating surface portion 20 of the exposed surface 19 of the housing 11 that is in a positional relationship facing the fixed slit plate 32 that is disposed. A light receiving element 23 is installed inside. In this case, the light receiving element 23 is installed in a positional relationship facing the light emitting element 26 provided in the circuit board 25.

  Further, the seat surface portion 20 is formed with a pair of groove portions 24 and 24 each having a substantially L shape so as to face the fixed slit plate 32 in each of the two sides, and is supplied into these groove portions 24. The fixed slit plate 32 can be firmly fixed to the seat surface portion 20 side as shown in FIG.

  Next, the operation and effect of the present invention having the above-described configuration will be described. The fixed slit plate 32 is inserted into the positioning pin 21 through the guide hole 39, so that it is immediately and accurately placed on the exposed surface 19 of the housing 12. It can be positioned and fixed. In addition, the fixed slit plate 32 is stably fixed in position over a long period of time by supplying an adhesive into the groove portion 24 formed on the exposed surface 19 of the housing 12 and bonding and fixing it to the housing 12 side. I can keep it.

  Further, the rotating disk 42 is fed to the rotating cylinder 14 side through the insertion hole 46 and is fixed to the flange portion 14a so that the rotating cylinder 14 can be driven by the rotation of the rotating cylinder 14. Can be fixed in position. In this case, since a plurality of tongue pieces 47 that can be pressed against the rotating cylinder 14 with elasticity are projected from the hole edge 46 a of the insertion hole 46, the protruding pieces 47 are connected to the rotating cylinder 14. The rotary disk 42 can be more stably disposed by press-contacting to the side.

  In this way, the fixed slit plate 32 fixed in position in the housing 12 and the rotating disk 42 rotatably arranged are fixed to each other as a separate fixed side slit 34 on the fixed slit plate 32 side. In contrast to the three-phase (UVW phase) corresponding portion 36 formed for each phase by the side short holes 35, the rotating disk 42 side is not provided in the circumferential direction for each phase in the three phases (UVW phase) provided as the rotation-side slit 44. The row | line | column of the some circular arc-shaped rotation side short hole 45 pierced continuously can be made to face at the time of the rotation.

  Further, the rotation-side slit 44 is formed as a row of a plurality of discontinuous arc-shaped rotation-side long holes 45 formed at equal intervals in the circumferential plane direction for each phase using a metal thin piece as a base material. In addition, it is possible to maintain necessary structural strength while realizing the weight reduction of the rotating disk 42 itself.

  Further, when the arc-shaped fixed side short holes 35 and the respective arc-shaped rotating side short holes 45 are formed based on the arrangement relationship shown in FIG. 6, the rotating side slit 44 side is fixed when the rotating disk 42 rotates. As long as it is in a positional relationship facing the side slit 34 side, the light emitted from the light emitting element 29 can be continuously received by the light receiving element 23 under the light intensity pattern shown in FIG. In addition, (b)-(g) in the graph of FIG. 6 shows the light intensity corresponding to (b)-(g) in FIG. 6, respectively.

  This will be described in more detail with reference to FIG. 6. Assume that the arc-shaped fixed side short hole 35 is fixed in position as shown in FIG. At this time, the effective light transmission area of the arc-shaped fixed side short hole 35 itself is the actual surface size.

  Further, it is assumed that each arcuate rotation side short hole 45 has moved to the position shown in FIG. At this time, the arcuate rotation-side short hole 45 located in the middle of the three in FIG. 6B forms a face-matching region 55 that perfectly faces the arc-shaped fixed-side short hole 35. Thus, the light intensity received by the light receiving element 23 is maximized as shown in the position (b) in FIG.

  As the rotating disk 42 further rotates, the arcuate rotation side short hole 45 located in the middle in FIG. 6B has an arcuate fixed side short hole at its left end as shown in FIG. As a result of moving to a position that protrudes from 35, the face-to-face matching region 55 is also reduced, and the light intensity received by the light receiving element 23 is narrowed accordingly, as shown at the position (c) in FIG.

  As the rotating disk 42 further rotates, the arcuate rotation side short hole 45 located in the middle in FIG. 6B has an arcuate fixed side short hole in the left half as shown in FIG. As a result of the left end portion of the arcuate rotation side short hole 45 that protrudes from the arc 35 moving into the arcuate fixed side short hole 35, the facing area 55 becomes smaller accordingly in FIG. As shown in the position, the light intensity received by the light receiving element 23 is still narrowed down.

  As the rotating disk 42 further rotates, the arcuate rotation side short hole 45 located in the middle in FIG. 6B is arcuate as shown in FIG. As a result of moving to a position protruding from the fixed side short hole 35 and moving the left half of the next arcuate rotation side short hole 45 into the arcuate fixed side short hole 35, the face-matching region 55 is also correspondingly increased. The light intensity received by the light receiving element 23 is still reduced as shown in the position (e) in FIG.

  As the rotating disk 42 further rotates, all of the arcuate rotation side short holes 45 located in the middle in FIG. 6B are arcuate fixed side short holes 35 as shown in FIG. 6F. As a result, the arcuate rotation side short hole 45 positioned next moves into the arcuate fixed side short hole 35 leaving the right end portion thereof, so that the face-to-face matching region 55 is also reduced accordingly. Therefore, as shown in the position (f) in FIG. 7, the light intensity received by the light receiving element 23 is still narrowed down.

  As the rotating disk 42 further rotates, the arcuate rotation side short holes 45 located on the right side of the three in FIG. 6B are arcuate fixed side short holes as shown in FIG. Thus, a face-matching region 55 that completely faces face-to-face 35 is formed, and the light intensity received by the light-receiving element 23 is maximized as shown at position (g) in FIG.

  That is, the light intensity received by the light receiving element 23 is the light reception intensity shown in FIG. 7 in which a noise component is placed on the waveform signal (light intensity signal) as long as the discontinuous arc-shaped rotation side short holes 45 continue. The pattern will be repeated.

  In addition, the received light intensity pattern shown in FIG. 7 is obtained by performing a necessary correction process, for example, in FIG. 16A obtained through the rotation-side slit 117 of the rotary disk 115 shown in FIG. 12 using a glass substrate. As shown, it can be outputted as a smooth continuous waveform signal (light intensity signal).

  On the other hand, when the arc-shaped fixed short holes 35 and the respective arc-shaped rotating short holes 45 are formed based on the arrangement relationship shown in FIG. 8, the rotating slit 44 side is fixed when the rotating disk 42 rotates. As long as it is in a positional relationship facing the side slit 34 side, the light emitted from the light emitting element 29 can always be received by the light receiving element 23 under a substantially constant light intensity as shown in FIG. In addition, (b)-(g) in the graph figure of FIG. 9 shows the light intensity corresponding to (b)-(g) in FIG. 8, respectively.

  This will be described in more detail with reference to FIG. 8. Assume that the arc-shaped fixed side short hole 35 is fixed in position as shown in FIG. At this time, the effective light transmission area of the arc-shaped fixed side short hole 35 itself is the actual surface size.

  Each arcuate rotation side short hole 45 moves to the position shown in FIG. 8B as the rotating disk 42 rotates. At this time, the arcuate rotation side short hole 45 located in the middle of the three in FIG. 8B coincides with the central region of the arcuate fixed side short hole 35, while the remainder located on the left and right sides. This area is shielded. That is, the light receiving element 23 passes the light emitted from the light emitting element 29 through the arc-shaped rotation-side short hole 45, thereby the surface of the arc-shaped rotation-side short hole 45 that is a confronting region 55 with the arc-shaped fixed-side short hole 35. As a result of narrowing down to a light receiving area equivalent to the size, the light intensity received by the light receiving element 23 also shows the level shown at the position (a) in FIG.

  Thereafter, the arcuate rotation-side short hole 45 located in the middle in FIG. 8B further moves to the left to the left of the arcuate fixed-side short hole 35 as shown in FIG. 8C. Covering the offset area, the remaining area is shielded. As a result, the light receiving element 23 is narrowed down to a light receiving area equivalent to the surface size of the arcuate rotation side short hole 45 that is a face-to-face matching region 55 with the arcuate fixed side short hole 35 as in FIG. Accordingly, light is received under the light intensity at the level shown in the position (b) in FIG.

  As the arcuate rotation side short hole 45 located in the middle in FIG. 8B further moves leftward, a part of the arcuate rotation side short hole 45 is arcuate as shown in FIGS. 8D and 8E. It gradually protrudes from the fixed side short hole 35. However, at this time, a part of the arcuate rotation side short hole 45 located on the right side in FIG. 8B gradually enters the arcuate fixed side short hole 35. That is, the arc-shaped fixed side short hole 35 is covered with the surface matching area 55 of the adjacent arc-shaped rotation side short holes 45, 45 as the surface size of one arc-shaped rotation side short hole 45. . As a result, the light receiving element 23 is narrowed down to a light receiving area equivalent to the surface size of one arcuate rotation side short hole 45 as in (b), and in FIGS. 9 (d) and (e). The light is received under the light intensity of the level shown in the position.

  The arcuate rotation side short hole 45 located in the middle in FIG. 8B completely moves out of the arcuate fixed side short hole 35 as shown in FIG. 8F by moving further leftward. It will be. However, the arc-shaped rotation-side short hole 45 located on the right side of the arc-shaped rotation-side short hole 35 has already completely entered the arc-shaped fixed-side short hole 35, and a face-matching region 55 is formed between the arc-shaped fixed-side short hole 35. Form and overlap. As a result, the light receiving element 23 is narrowed down to a light receiving area equivalent to the surface size of one arcuate rotation side short hole 45 as in FIG. 8B, and the position of FIG. The light is received under the light intensity at the level shown in FIG.

  Thus, the newly entered arcuate rotation side short hole 45 reaches the position shown in FIG. 8 (a) as shown in FIG. 8 (g). As a result, the light receiving element 23 is narrowed down to a light receiving area equivalent to the surface size of the arcuate rotation side short hole 45 that is a face-to-face matching region 55 with the arcuate fixed side short hole 35 as in FIG. Accordingly, light is received under the light intensity at the level shown in the position (g) in FIG. 9, and thereafter, under the same positional relationship as shown in (c) to (f). Will move.

As a result, when the arc-shaped fixed side short holes 35 and the respective arc-shaped rotation side short holes 45 are formed based on the arrangement relationship shown in FIG. The light that has passed through the rotation side short hole 45 also appears in the waveform shown in FIG. In other words, as long as the rotary slit 42 rotates, the light receiving element 23 always receives the same light intensity under a substantially constant light receiving area as long as the rotation side slit 44 side faces the fixed side slit 34 side. For example, a smooth continuous waveform signal (light intensity signal) as shown in FIG. 16A obtained through the rotation side slit 117 of the rotary disk 115 shown in FIG. 12 using a glass substrate is shown in FIG. so that it can be outputted as a signal P _1.

Since the arrangement relationship between the arc-shaped fixed side short hole 35 and the arc-shaped rotation side short hole 45 is as described above, the rotation-side slit is usually discontinuous as shown in FIG. if it is formed as a series of arc-shaped rotating side short hole should be detected as a pulse-shaped discrete waveform signal P ₂ as shown FIG. 16 (b).

However, when the arc-shaped fixed side long hole 35 and the arc-shaped rotation side short hole 45 are formed in an arrangement relationship that can always ensure a substantially constant light receiving area as shown in FIGS. As shown in FIG. 9, it can be detected as a continuous waveform signal P ₁ without flicker.

  Further, the fixed side through hole 38 formed in the light shielding surface of the fixed slit plate 34 and the protruding piece portion 49 projecting in the same plane direction from the outer peripheral edge 42a of the rotary disk 42 are opposed to the fixed side through hole 38. The rotation direction and the number of rotations, which are the ABZ phase, can be detected freely between the rotation side through hole 51 formed in the light shielding surface.

  Moreover, the surrounding blank area excluding the projecting piece 49 in the rotating disk 42 can be used structurally by making it a light-transmitting area equivalent to the slit pattern of the rotating disk made of a glass substrate.

  The above is the description of the present invention based on the illustrated examples, and various modifications can be made to the specific contents without departing from the gist of the present invention. For example, the fixed-side slit 34 and the rotation-side slit 44 can be increased or decreased according to the desired number of phases. In addition, the light receiving element 23 and the light emitting element 29 can be arranged with a positional relationship opposite to that in the illustrated example. In this case, the entire optical rotary encoder 11 can accommodate the thick light emitting element 29 side in the housing 12, so that the thickness can be reduced accordingly.

The disassembled perspective view about an example of this invention which abbreviate | omits and shows a part of structural member. The principal part perspective view which shows the state after the assembly about the example shown in FIG. Explanatory drawing which shows the planar shape of the rotating disk and fixed slit board which comprise this invention. The principal part expansion explanatory drawing shown on the basis of correspondence with FIG. The longitudinal cross-sectional view which shows the example of the whole structure after assembling. Explanation schematically showing an example of both coincident surfaces (translucent areas) secured when two arc-shaped rotating side short holes adjacent in the same phase rotate on the corresponding arc-shaped fixed side short holes. Figure. Explanatory drawing which shows the waveform signal (light intensity signal) obtained on the basis of the correspondence with FIG. The suitable example of both matching surfaces (light transmission area) ensured when two arc-shaped rotation side short holes adjacent within the same phase rotate on the corresponding arc-shaped fixed side short hole is shown typically. Illustration. Explanatory drawing which shows the waveform signal (light intensity signal) obtained on the basis of the correspondence with FIG. Explanatory drawing which shows the arrangement | positioning relationship between the arc-shaped fixed side short hole and the arc-shaped rotation side short hole in the suitable example shown in FIG. 8 as a relational expression. The top view shown in the state which installed the fixed slit board and the rotation disc in the housing. The disassembled perspective view about the prior art example which abbreviate | omits and shows a part of structural member. The top view about the prior art example shown in the state which installed the fixed slit board and the rotation disc in the housing. The top view which expands and shows the prior art example of a rotating disk, and the principal part. Explanatory drawing which shows the shape example of the rotation side slit assumed when forming a rotation disc with a thin metal plate according to a pattern as (a)-(c). Explanatory drawing which shows the waveform signal (light intensity signal) obtained on the basis of a correspondence with FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 Optical rotary encoder 12 Housing 13 Passing hollow part 14 Rotating cylinder 14a Flange part 15 Fixed washer 16 Screw material 17 Peripheral wall part 17a Step part 18 Notch part 19 Exposed surface 20 Seating surface part 21 Positioning pin 22 Recessed part 23 Light receiving element 24 Groove part 25 Bearing 28 Circuit board 29 Light emitting element 32 Fixed slit plate 33 Light blocking surface 34 Fixed side slit 35 Arc-shaped fixed side short hole 36 Three phase (UVW phase) corresponding part 37 Z phase (ABZ phase) corresponding part 38 (37a, 37b, 37c) Fixed side through hole 39 Guide hole 42 Rotating disk 42a Outer peripheral edge 43 Light blocking surface 44 Rotating side slit 45 Arc-shaped rotation side short hole 46 Insertion hole 46a Hole edge 47 Tongue piece 48 Through hole 49 Projection piece 50 Light blocking surface 51 ( 51a, 51b, 51c) Rotating side through hole 52 Cover 53 Peripheral end surface 55 Meeting area P ₁ Continuous waveform signal P ₂ Discontinuous waveform signal

Claims (4)

The rotating slits as concentric circles with different radii as the code pattern over multiple phases are concentrically formed on each phase in the circular plane direction of the light shielding surface, and the rotating slits for each phase face each other individually. A fixed slit plate having a fixed slit formed on each light shielding surface for each phase under the positional relationship between the light emitting element in the housing and the light receiving element that receives light from the light emitting element. In the optical rotary encoder
At least the rotating disk has a discontinuous plurality of metal bases, and each of the slits on the rotating side is formed in a circular plane direction so that continuous light reception by the light receiving element of the light from the light emitting element is freely perforated. An optical rotary encoder characterized in that the structural strength is maintained by arranging each of the arc-shaped rotation side short holes as a row. The fixed slit plate is formed by arranging a thin piece of metal as a base material, and arranging each of the fixed side slits as one arcuate fixed side short hole formed by each phase,
The row of the arc-shaped rotation side short holes and the arc-shaped fixed side short holes for each phase is such that the light from the light emitting element always has a substantially constant light receiving area with respect to the light receiving element when the rotating disk rotates. The optical rotary encoder according to claim 1, wherein the optical rotary encoder is arranged under an arrangement relationship that reaches The fixed-side through hole formed in the light-shielding surface of the fixed slit plate and the protruding piece projecting in the same plane direction from the outer peripheral edge of the rotating disk can freely shield the opposite side of the fixed-side through-hole. 3. The optical rotary encoder according to claim 1, wherein the rotation direction and the number of rotations of the rotating disk can be freely detected between the rotation side through-hole formed in the surface. The rotating disk includes an insertion hole for mounting on a rotating cylinder that is rotatably arranged in the housing, and the hole edge of the insertion hole is freely press-contacted with elasticity of the rotating cylinder. The optical rotary encoder according to any one of claims 1 to 3, wherein a plurality of tongue pieces are protruded.

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