JP5657743B2 - Optical rotary encoder for easy positioning adjustment - Google Patents

Description

  The present invention relates to an optical rotary encoder that can be easily positioned and adjusted.

  In general, an optical rotary encoder has a light emitting element, a fixed slit plate having a slit through which light emitted from the light emitting element passes, and a slit that is disposed to face the fixed slit plate and rotates integrally with a rotating shaft. A rotating slit plate; and a light receiving element that receives light that has passed through the slits of the fixed slit plate and the rotating slit plate. In order to increase the rotation detection accuracy by this type of optical rotary encoder, it is necessary to accurately position the fixed slit plate with respect to the housing that rotatably supports the rotating shaft.

  In this regard, Patent Document 1 discloses a light emitting component mounting seat in which a housing portion and a mounting surface are formed, and a light emitting element housed in the housing portion and a fixed scale (fixed slit plate) attached to the mounting surface. An optical rotary encoder is described in which an annular light-emitting component mounting seat having the above is fitted to the boss portion of the housing by shrink fitting.

JP 2006-23226 A

  However, in the method described in Patent Document 1, a shrink fitting process is required to integrate the housing and the light emitting component mounting seat, and it is difficult to easily and quickly assemble the optical rotary encoder.

An optical rotary encoder according to an aspect of the present invention includes a housing, a rotary shaft supported on the housing so as to be rotatable about an axis, a rotary slit plate that is provided so as to be rotatable integrally with the rotary shaft, and has a slit. A fixed slit plate having a slit disposed opposite to the rotary slit plate, a light emitting unit for irradiating light toward the slit of the fixed slit plate, and a light emission that has passed through the slit of the rotary slit plate and the slit of the fixed slit plate A light receiving unit that receives light from the unit. The housing has an attachment portion to which the fixed slit plate is attached. The attachment portion protrudes in the direction of the axis , and is movable in the first direction perpendicular to the axis. A first protrusion that abuts one end surface of the first slit and restricts the position of the fixed slit plate in the first direction, and projects in the direction of the axis , along the second direction orthogonal to the axis and the first direction, respectively. And a second projection that abuts against one end surface of the fixed slit plate in the second direction and restricts the position of the fixed slit plate in the second direction .

  According to the present invention, the first protrusion and the second protrusion are provided on the housing so as to restrict the position of the fixed slit plate in the direction orthogonal to the axis, so that the optical rotary encoder can be easily and quickly operated. Can be assembled.

1 is a cross-sectional view showing a schematic configuration of an optical rotary encoder according to an embodiment of the present invention. FIG. 2 is a plan view of a bottom plate of the housing according to FIG. 1. FIG. 3 is an arrow III view of FIG. 2. The top view which shows the state which attached the fixed slit board to the attaching part of FIG. The figure which shows the modification of FIG.

  Hereinafter, an optical rotary encoder according to an embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a cross-sectional view showing a schematic configuration of an optical rotary encoder 100 according to an embodiment of the present invention. Below, for convenience, the vertical direction is defined as shown in the figure, and the configuration of each part will be described according to this definition. The optical rotary encoder 100 includes a housing 1, a shaft 2, a rotary slit plate 3, a fixed slit plate 4, a light emitting unit 5 and a light receiving unit 6, and detects the rotation (rotational speed and position) of the rotating body. As an example of the rotating body, the rotation of the servo motor is detected below.

  The housing 1 has a cylindrical portion 10 centering on an axis L0 extending in the vertical direction, an upper plate portion 11 that closes the upper surface of the cylindrical portion 10, and a bottom plate portion 12 that closes the bottom surface of the cylindrical portion 10. A housing space SP is formed inside the housing 1. The tube portion 10 and the upper plate portion 11 are integrally formed, and the tube portion 11 is fixed to the upper surface 120 of the bottom plate portion 12 with bolts. A through hole 13 is opened at the center of the bottom plate portion 12, and a bearing 14 is attached to the through hole 13.

  The shaft 2 extends in the vertical direction along the axis L0. The shaft 2 is attached to the inside of the bearing 14 and is supported via the bearing 14 so as to be rotatable about the axis L0 from the housing 1. A lower end portion of the shaft 2 protrudes from the housing 1, and a rotating shaft of a servo motor is connected to the lower end portion.

  The rotary slit plate 3 has a disk shape, and its central portion is attached to the other end portion of the shaft 2. Accordingly, the rotating slit plate 3 rotates integrally with the shaft 2 in the storage space SP in the housing 1. The rotary slit plate 3 is provided with slits 31 in a predetermined pattern. For example, a plurality of slits 31 are provided at equal intervals in the circumferential direction around the axis L0.

  The fixed slit plate 4 has a rectangular shape, for example (see FIG. 4), and is attached to the attachment portion 7 provided on the upper surface 120 of the bottom plate portion 12 of the housing 1. In this attached state, the fixed slit plate 4 is disposed below the rotary slit plate 3 at a predetermined distance from the rotary slit plate 3 in parallel and opposite to the rotary slit plate 3. The fixed slit plate 4 is provided with slits 41 having a predetermined pattern corresponding to the slits 31 of the rotary slit plate 3. The configuration of the attachment portion 7 will be described later.

  The light emitting unit 5 is constituted by a light emitting element diode, for example. The light emitting unit 5 is held by a holder 51. The holder 51 is provided on the upper surface 120 of the bottom plate 12 of the housing 1 and is accommodated in the recess 121. The light emitting unit 5 is disposed facing the slit 41 of the fixed slit plate 4 and irradiates light toward the slit 41.

  The light receiving unit 6 is configured by, for example, a light receiving element diode. Above the rotary slit plate 3, the printed circuit board 61 is supported by a plurality of pillars 122 erected from the upper surface 120 of the bottom plate part 12, and the light receiving unit 6 is mounted on the printed circuit board 61. That is, the light receiving unit 6 is disposed above the light emitting unit 5 with the fixed slit plate 4 and the rotating slit plate 3 interposed therebetween, and can receive light from the light emitting unit 5 through the slits 41 and 31.

  According to the optical rotary encoder 100 described above, the light from the light emitting unit 5 is converted into parallel light parallel to the axis L 0 via the slit 41 of the fixed slit plate 4 and is irradiated toward the rotary slit plate 3. The irradiated light passes through the slit 31 of the rotating slit plate 3 according to the rotation of the shaft 2 or is blocked without passing, and the light passing through the slit 31 is received by the light receiving unit 6 on and off. . Accordingly, the light receiving unit 6 can output a signal corresponding to the rotation of the shaft 2 and detect the rotation (rotation speed and position) of the servo motor connected to the shaft 2. In this case, in order to increase the rotation detection accuracy by the rotary encoder 100, it is necessary to increase the positional accuracy of the fixed slit plate 4 in the housing 1. Therefore, in the present embodiment, the attachment portion 7 of the fixed slit plate 4 is configured as follows.

  FIG. 2 is a plan view of the bottom plate 12 of the housing 1 showing the configuration of the attachment portion 7 (a view of the bottom plate 12 as viewed from above). In the following, as shown in FIG. 2, two directions orthogonal to each other in the plane orthogonal to the vertical axis L <b> 0 are defined as the front-rear direction and the left-right direction.

  As shown in FIG. 2, the bottom plate portion 120 has a rectangular square shape cut out into a rectangular shape, and bolts for mounting the cylindrical portion 10 of the housing 1 are inserted in the vicinity of the cutout portion 123. A through hole 124 and a through hole 125 into which a bolt for mounting the servo motor is inserted are opened. Around the through-hole 13, recesses 126 are provided at equal intervals in three circumferential directions, and pillars 122 for supporting the printed circuit board 61 are attached to the recesses 126, respectively.

  A substantially rectangular recess 121 extending in the front-rear and left-right directions is provided in front of the through-hole 13, and a holder 51 that holds the light emitting unit 5 is attached to the recess 121. Three protrusions 71 to 73 project from the left and lower sides of the recess 121 upward. The protrusions 71 to 73 each constitute the attachment portion 7.

  FIG. 3 is a side view of the protrusions 71 to 73 as viewed from the side, that is, an arrow III view of FIG. The protrusions 71 to 73 are different from each other only in the attachment position and the attachment direction, and these shapes are equal to each other. The protrusion 72 and the protrusion 73 have the same mounting direction.

  As shown in FIGS. 2 and 3, the protrusions 71 to 73 have a rectangular parallelepiped upper end corner cut into a rectangular shape, and the right side of the protrusion 71 and the front sides of the protrusions 72 and 73 are horizontal surfaces, respectively. 71a-73a and vertical surfaces 71b-73b are formed. The horizontal planes 71a to 73a are formed at the same height in the vertical direction and exist on the same plane orthogonal to the axis L0. The vertical surface 71b of the protrusion 71 extends in the up-down direction and the front-rear direction. The vertical surfaces 72b and 73b of the protrusions 72 and 73 extend in the vertical direction and the horizontal direction, respectively, and the vertical surfaces 72b and 73b are on the same plane.

  FIG. 4 is a plan view showing a state in which the fixed slit plate 4 is attached to the attachment portion 7 of FIG. As shown in FIG. 4, the fixed slit plate 4 is disposed on the horizontal surfaces 71 a to 73 a of the projecting portions 71 to 73 and is fixed to the bottom plate portion 12 (projecting portions 71 to 73) of the housing 1 with an adhesive. In this fixed state, the left end surface 42 of the fixed slit plate 4 is in contact with the vertical surface 71 b of the protrusion 71, and the rear end surface 43 is in contact with the vertical surfaces 72 b and 73 b of the protrusions 72 and 73. That is, the position of the fixed slit plate 4 in the left-right direction is regulated by the protrusion 71, the position in the front-rear direction is regulated by the protrusions 72 and 73, and the fixed slit plate 4 is positioned by the protrusions 71 to 73.

  The slit 41 of the fixed slit plate 4 has an arc shape centered on the axis L <b> 0, and the light emitting unit 5 exists below the slit 41. Since the light emitting unit 5 is positioned by the concave portion 121 of the housing 1, the positional accuracy of the slit 41 with respect to the light emitting unit 5 is increased by positioning the fixed slit plate 4 by the protrusions 71 to 73 of the housing 1 as described above. be able to. Further, since the rotary slit plate 3 is provided with the through hole 13 of the housing 1 as a reference via the shaft 2, the positional accuracy of the slit 31 of the rotary slit plate 3 with respect to the slit 41 of the fixed slit plate 4 is also high.

  The assembly of the optical rotary encoder 100 according to this embodiment is performed as follows, for example. First, the holder 51 holding the light emitting unit 5 is housed and fixed in the recess 121 of the bottom plate 12 of the housing 1. Next, on the horizontal planes 71a to 73a of the protrusions 71 to 73, the fixed slit plate 4 is moved to the left and rear, and the left end surface 42 and the rear end surface 43 of the fixed slit plate 4 are respectively perpendicular to the protrusions 71 to 73. It is made to contact | abut to 71b-73b. In this state, the fixed slit plate 4 is fixed to the bottom plate portion 12 with an adhesive.

  Further, the shaft 2 to which the rotary slit plate 3 is attached is inserted into the through hole 13 via the bearing 14, and the rotary slit plate 3 is disposed above the fixed slit plate 4. Further, the printed circuit board 61 provided with the light receiving unit 6 is disposed above the rotating slit plate 3 via a column part 122 erected from the upper surface 120 of the bottom plate part 12. Finally, the cylindrical portion 10 and the upper plate portion 11 of the housing 1 are fixed to the upper surface 120 of the bottom plate portion 12 with bolts, and the assembly of the optical rotary encoder 100 is completed.

  As described above, according to the present embodiment, as the mounting portion 7 of the fixed slit plate 4 on the upper surface 120 of the bottom plate portion 12 of the housing 1, the protrusion 71 that regulates the position of the fixed slit plate 4 in the left-right direction, and the front-rear direction The protrusions 72 and 73 for restricting the position of the fixed slit plate 4 are provided so as to protrude. Accordingly, the fixed slit plate 4 can be easily and quickly positioned by the protrusions 71 to 73, and the optical rotary encoder 100 can be assembled easily and quickly.

  Moreover, since the horizontal planes 71a to 73a are formed on the protrusions 71 to 73 and the fixed slit plate 4 is placed on the horizontal plane, the fixed slit plate 4 can be easily positioned in the vertical direction. Since the three protrusions 71 to 73 are positioned in the vicinity of the three corners (front left corner, rear left corner, and rear right corner) of the fixed slit plate 4, the fixed slit plate 4 can be positioned stably. . In this case, since the protrusions 71 to 73 are partially provided, the protrusions 71 to 73 can be formed in a small size.

  The structure of the attachment part 7 is not restricted to what was mentioned above. FIG. 5 is a plan view illustrating an example of another configuration of the attachment portion 7. In FIG. 5, an L-shaped protrusion 75 is formed on the upper surface 120 of the bottom plate 12 instead of the three protrusions 71 to 73. The projecting portion 75 includes a projecting portion 76 extending in the front-rear direction and a projecting portion 77 extending in the left-right direction, and a horizontal surface 761 and a vertical surface 762 on the right side of the projecting portion 76. A horizontal plane 771 and a vertical plane 772 are respectively formed on the front side of the. Further, in FIG. 5, a protruding portion 421 protruding leftward is formed on the left end surface 42 of the fixed slit plate 4, and protruding portions 431 and 432 protruding forward are formed on the rear end surface 43.

  The fixed slit plate 4 is placed on the horizontal planes 761 and 771 of the projecting portion 75, whereby the vertical position of the fixed slit plate 4 is regulated. Further, the protrusion 421 of the fixed slit plate 4 abuts on the vertical surface 762 of the protrusion 76, and the protrusions 431 and 432 abut on the vertical surface 772 of the protrusion 77, thereby causing the fixed slit plate 4 to move in the front-rear and left-right directions. The position is regulated. Thus, by forming the protrusion 75 in an L shape, the positioning range and the support range of the fixed slit plate 4 can be widened, and the fixed slit plate 4 can be positioned and supported stably. In addition, by providing the protrusions 421, 431, and 432 on the fixed slit plate 4, it is not necessary to finish the entire left end surface 42 and rear end surface 43 of the fixed slit plate 4 with high accuracy, and the processing cost can be reduced.

  A protrusion (first protrusion) that regulates the position of the fixed slit plate 4 in a first direction (left and right in FIGS. 4 and 5) orthogonal to the axis L0, and orthogonal to the axis L0 and the first direction, respectively. A protrusion (second protrusion) that restricts the position of the fixed slit plate 4 in the second direction (the front-rear direction in FIGS. 4 and 5) projects in the direction of the axis L0 (upward in FIGS. 4 and 5). For example, the configuration of the attachment portion 7 is not limited to that described above.

  In the above embodiment (FIG. 4), the three protrusions 71 to 73 are provided as the attachment portion 7. However, the fixed slit plate 4 is positioned if there are at least two vertical surfaces 71b and 72b or two vertical surfaces 71b and 73b. Since it is possible, the protrusion 72 or the protrusion 73 can be omitted. For example, a cylindrical surface is formed instead of the vertical surfaces 71b to 73b, and the protrusion 71 as the first protrusion and the protrusions 72 and 73 as the second protrusion and the fixed slit plate 4 are in point contact instead of surface contact. You may do it. In this case, in order to restrict the position of the fixed slit plate 4 in the front-rear and left-right directions, at least three protrusions 71 to 73 are required.

  In the above-described embodiment (FIG. 5), the protrusion 75 is formed in an L shape in plan view and the first protrusion 76 and the second protrusion 77 are connected to each other. You may form in U shape. Although the protruding portions 421, 431, and 432 are formed on the side end surfaces of the fixed slit plate 4, that is, the left end surface 42 and the lower end surface 43, respectively, the configurations of the first protruding portion and the second protruding portion are not limited thereto.

  The fixed slit plate 4 of FIG. 5 can also be applied to the configuration of FIG. 4, and conversely, the fixed slit plate 4 of FIG. 4 can also be applied to the configuration of FIG. The rotary slit plate 3 is fixed to the upper end portion of the shaft 2, but if the shaft 2 (rotary shaft) and the rotary slit plate 3 rotate integrally, the configuration of the shaft 2 and the rotary slit plate 3 is not limited. It may be a thing. Although the fixed slit plate 4 is disposed facing the light emitting unit 5, the rotating slit plate 3 may be disposed facing the light emitting unit 5, and the fixed slit plate 4 may be disposed facing the rotating slit plate 3. .

  Although the case where the rotation of the servo motor is detected by the optical rotary encoder 100 has been described above, the optical rotary encoder 100 can also be applied to the case where the rotation of another rotating body is detected.

  The above description is merely an example, and the present invention is not limited to the above-described embodiments and modifications unless the features of the present invention are impaired. The constituent elements of the embodiment and the modified examples include those that can be replaced while maintaining the identity of the invention and that are obvious for replacement. That is, other forms conceivable within the scope of the technical idea of the present invention are also included in the scope of the present invention. Moreover, it is also possible to arbitrarily combine one or more of the above-described embodiments and modified examples.

DESCRIPTION OF SYMBOLS 1 Housing 2 Shaft 3 Rotating slit board 4 Fixed slit board 5 Light emission part 6 Light receiving part 7 Mounting part 71-73, 75 Protrusion part 100 Optical rotary encoder 421,431,432 Projection part L0 Axis line

Claims (3)

A housing;
A rotating shaft supported by the housing so as to be rotatable about an axis;
A rotary slit plate provided so as to be rotatable integrally with the rotary shaft, and having a slit;
A fixed slit plate disposed opposite to the rotating slit plate and having a slit;
A light emitting unit that emits light toward the slit of the fixed slit plate;
In the optical rotary encoder comprising: a light receiving unit that receives light from the light emitting unit that has passed through the slit of the rotating slit plate and the slit of the fixed slit plate,
The housing has an attachment portion to which the fixed slit plate is attached,
The mounting portion is
The fixed slit plate in the first direction is in contact with one end surface of the fixed slit plate protruding in the direction of the axis and movable along a first direction orthogonal to the axis. A first protrusion that regulates the position of
Projecting in the direction of the axis, and abutting against one end surface in the second direction of the fixed slit plate movable along a second direction orthogonal to the axis and the first direction , the second direction An optical rotary encoder comprising: a second projecting portion that regulates a position of the fixed slit plate. The optical rotary encoder according to claim 1,
The optical rotary encoder, wherein the first protrusion and the second protrusion are connected to each other. The optical rotary encoder according to claim 1 or 2,
The fixed slit plate has a first projecting portion projecting in the first direction and a second projecting portion projecting in the second direction on a side end surface.

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