JPS6125018A - Optical type rotary encoder - Google Patents

Abstract

PURPOSE:To eliminate the deviation of the mutual positions of a light receiving element, a phase plate and a light guide, by constituting a light receiving block by forming a unitary body by the light receiving element, the phase plate and the light guide. CONSTITUTION:In a body 11, a light projecting block 2, in which a light emitting element is mounted, a rotary block, which is constituted by mounting a code wheel 31 on a rotary shaft 32, and a light receiving block 4 provided with a light receiving element. One end part of the rotary shaft 32 is protruded from the body 11 through a through hole formed in the body 11. The light receiving block 4 is constituted by forming a unitary body by the light receiving element, a phase plate and a light guide.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field 1] The present invention relates to an optical rotary encoder, and more particularly, to an optical rotary encoder that is often used to perform feedback control of a motor by detecting the rotation speed and rotation direction of a motor. It is something.

[Background Art] Generally, as an optical rotary encoder for detecting the rotation angle of a motor or the like, one having a structure as shown in FIG. 17 or 18 is provided. That is, this type of optical rotary encoder is basically formed in a disk shape and rotates together with the rotating shaft 32.
A code wheel 31 in which a large number of slits are periodically formed along the circumferential direction of the code wheel 2, a light emitting element 21 that emits light toward the code wheel 31, and a light emitting element 21 that receives light transmitted through the slits of the code wheel 31. has a plurality of light-receiving elements 41 for converting into electrical signals, and the plurality of light-receiving elements 41 are arranged at positions to detect mutually different phases with respect to the slit provided in the code wheel 31. There is. Therefore, when the code wheel 31 rotates, the direction of rotation can be determined from the phase difference between the signals detected by each light receiving element 41, and the number of rotations can be determined from the period of the signals.

By the way, between the code wheel 31 and the light receiving element 41, there is a light guide 45 for scattering prevention and a phaser for shaping the waveform of the transmitted light so that the light passing through the code wheel 31 is reliably guided to the light receiving element 41. Although the plate 44 is interposed, conventionally these members are individually arranged inside the casing 1, so the joints between the members may become loose during transportation or use. There is a problem in that the positions of the members are shifted, and as a result, the amount of light received by the light receiving element 41 changes, the output waveform becomes unstable, and measurement errors occur.

[Objective of the Invention 1 The present invention has been made in view of the above-mentioned points, and its main purpose is to form a light receiving element, a light guide, and a phase plate into an integral block,
It is an object of the present invention to provide an optical rotary enhancer which prevents measurement errors by preventing misalignment between these members and which has good working efficiency during assembly.

[Disclosure 1 of the Invention In the present invention, by integrating the light receiving element, the phase plate, and the light guide to form a light receiving block, it is possible to prevent the light receiving element, the phase plate, and the light guide from being misaligned with each other. An optical rotary encoder is disclosed.

(Example) Hereinafter, an example of the present invention will be described based on the drawings. Second
As shown in the figure, the casing 1 includes a bottomed cylindrical body 11 with an open rear surface, an end cap 12 that closes the opening of the body 11, and a bottomed cylindrical body with an open front surface that is fitted onto the body 11. It is composed of a cover 13 having a shape. As shown in FIG. 14, a holding step 14 is formed on the inner surface of the body 11 near the opening, and a thin piece 15 is formed between the holding step 14 and the opening edge around the entire circumference of the opening. There is.

The end cap 12 is connected to the body 11 from the opening of the body 11.
It is inserted into the inside and is locked by the holding step 14. A tapered portion 16 whose diameter gradually decreases toward the rear is formed on the outer peripheral edge of the end cap 12, and the thin portion 15 is conically bent along the tapered portion 16 by a conical bending punch 8, as shown in FIG. By processing, the end cap 12 is held between the holding step portion 14 and the thin wall portion 15, and the body 11 and the end cap 12 are fixed together. In this way, the body 11 and the end cap 12 are fixed by caulking the thin wall portion 15 of the body 11, so compared to the case of fixing with bolts, the effort of tightening the bolts can be omitted, and the bolt tightening can be omitted. The cover 13 is inserted into the body 11 in a state where the end cap 12 and the body 11 are integrated with each other. An insertion hole 18 into which a bushing 17 is inserted is opened at the bottom of the cover 13, and the electric wire 9 is inserted through the bushing 17.
is brought out.

As shown in FIG. 1, a body 11 includes a light emitting block 2 in which a light emitting element 21 is inserted, a rotating block 3 configured by inserting a code wheel 31 into a rotating shaft 32, and a light receiving element 41. A light receiving block 4 having a light receiving block 4 is housed therein. Further, one end portion of the rotating shaft 32 protrudes from the body 11 through a through hole 19 formed in the body 11.

As shown in FIG. 4, the light projection block 2 includes a base 22 formed in a ring shape from an insulating material such as synthetic resin, and a light emitting element 21 such as an infrared light emitting diode fixed on the base 22. The bearing 24 is inserted into a through hole 23 formed in the center of the base 22. As shown in FIG.
5 in a fixed position within the body 11.

As shown in FIG. 5, the rotating block 3 has a code wheel 31 attached to a rotating shaft 32, and the code wheel 31 has a holding bush 33 press-fitted into the rotating shaft 32, and a holding bush 33 facing the holding bush 33. It is held between the disposed end bush 34 and rotates together with the rotating shaft 32. The code wheel 31 is shaped like a thin disk, and has a large number of direction detection slits 35 formed at equal intervals along the circumferential direction on its outer periphery, and is closer to the center than the direction detection slits 35. One rotation speed detection slit 36 is formed in the rotation speed detection slit 36 . The direction detection slit 35 and the rotation speed detection slit 36 are provided at positions corresponding to the light emitting element 21, and the light emitted from the light emitting element 21 passes through the direction detection slit 3.
5 and the rotation speed detection slit 36. One end of the rotating shaft 32 is supported by a bearing 24 provided on the light projecting block 2, and the shaft end is supported by an end cap 12, which will be described later.
It is supported by a bearing 51 provided in the.

The light receiving block 4 is placed on the opposite side of the light emitting block 2 across the code wheel 31, and as shown in FIG.
A substrate 42 is attached with three light receiving elements 41 that receive the light transmitted through the rotation speed detection slit 36 and converts it into an electric signal, and a correction slit 43 is formed at a position corresponding to each light receiving element 41. , phase plate 4
4 is interposed between the phase plate 44 and the substrate 42, and each light receiving element 41 receives the light transmitted through the phase plate 44.
It is composed of a light guide 45 that guides the light.

A pair of correction slits 43 are provided on the left and right at positions corresponding to the direction detection slit 35 of the code wheel 31, and one correction slit 43 is provided at a position corresponding to the rotation speed detection slit 36.

Each correction slit 43 is formed by a group of small slits, and corrects the light that passes through the direction detection slit 35 and the rotation speed detection slit 36 and whose intensity changes in a rectangular wave pattern so that it changes in a sine wave pattern. Three guide holes 46 are formed in the light guide 45 to correspond to each correction slit 43, and the inner peripheral surface of each guide hole 46 is black with a matte finish. Therefore, the light transmitted through each correction slit 43 is not scattered and is guided to each light receiving element 41 without interfering with each other. Light receiving element 41
The light receiving element 41 converts light into an electrical signal.
A processing circuit section (not shown) is mounted on the substrate 42 to which the electric signal is fixed, which processes the electric signal appropriately and outputs the processed signal.

A pair of connecting legs 65 protrudes from the rear surface of the light guide 45, and the narrow diameter portion formed at the tip of the connecting legs 65 is inserted into the connecting hole 49 formed in the substrate 42, and in this state, the connecting legs 65 are connected to the substrate 42. The light guide 45 is fixed together with adhesive or heat caulking.

Further, a coupling protrusion 47 is protruded from the front surface of the light guide 45, and the coupling protrusion 47 is shaped like e,
The light guide 45 and the phase plate 44 are fixed together by inserting the light guide 45 into the engagement hole 48 and applying heat to the tip of the engagement protrusion 47 to lock the light guide 45 into the engagement hole 48 . As a result, the board 42 and the light guide 45
and the phase plate 44 are integrated to form the light receiving block 4. The phase plate 44 and the light guide 45 may be integrated by simultaneous molding, as shown in FIGS. 12 and 13.

By the way, as shown in FIG. 1, a through-hole 52 is formed in the center of the end cap 12, a bearing 51 is inserted into the front half of the through-hole 52, and a female thread is inserted into the rear half of the through-hole 52. The bearing 51 supports one end of the rotating shaft 32 as described above.
As shown in FIG. 11, a bearing 51 is attached to the rotating shaft 32.
A locking step portion 37 is formed which comes into contact with the front end surface of the inner ring 54 of the inner ring 54 .

Further, a position adjustment screw 55 is screwed into the female threaded portion 53, and the front end surface of the position adjustment screw 55 abuts on the outer ring 56 of the bearing 51. Therefore, by moving the position adjustment screw 55 back and forth, a preload of about 5% of the rated load is applied to the bearing 51, and it is possible to prevent the bearing 51 from wobbling back and forth. Furthermore, since the front end surface of the inner ring 54 of the bearing 51 is in contact with the locking step 37 formed on the rotating shaft 32, the axial movement of the rotating shaft 32 can be adjusted by moving the position adjustment screw 55 forward or backward. It can also prevent exposure. In this way, instead of conventionally preventing rattling by stacking thrust washers of different thicknesses on the bearing 51 depending on the degree of rattling in the axial direction of the rotating shaft 32, a thrust washer can be inserted and installed. It is possible to prevent rattling in the axial direction of the rotary shaft 32 by a simple operation of adjusting the screwing amount of the position adjustment screw 55.

As shown in FIGS. 8 and 9, a pair of fixing screws 61 with sharp tips are inserted through the periphery of the end cap 12. As shown in FIGS. The fixing screws 61 are provided at positions that are rotated approximately 90 degrees left and right in the circumferential direction of the end cap 12 from positions corresponding to the light receiving elements 41 in the light receiving block 4. When the fixing screw 61 is fully screwed in, its tip will bite into the substrate 42 on the rear side of the light receiving block 4, pressing the light receiving block 4 toward the support piece 62 protruding from the light projecting block 2, and supporting the light receiving block 4. It is held between the piece 62 and the fixing screw 61. As shown in FIG. 7, at positions corresponding to both fixing screws 61 on the side surface of the body 11, long position adjustment openings 63 are provided along the circumferential direction.
are formed so that a jig 64 can be inserted into the body 11 and removed through both position adjustment openings 63. The tip of the jig 64 is shaped to engage with the base of a connecting leg 65 that connects the substrate 42 of the light receiving block 4 and the light guide 45. A slight gap is formed between the body 11 and the light receiving block 4, and by using a jig 64, the light receiving block 4 can be opened with the fixing screw 61 loosened.
is movable in a direction substantially perpendicular to the rotating shaft 32.

After moving the light receiving block 4 in this way, if the fixing screw 61 is tightened, the light receiving block 4 is held between the fixing screw 61 and the support piece 62, so that the food wheel 3
1 and the phase plate 44 is the phase plate L.
A constant distance is maintained before and after the movement of the hood wheel 31 and the light receiving element 41, and only the phase relationship between the food wheel 31 and the light receiving element 41 changes.
The phase difference between the outputs of each light receiving element 41 can be adjusted to a predetermined value. Thereby, it is possible to correct an error in assembling the light receiving block 4 with respect to the code wheel 31 during assembly, and it is possible to obtain a desired phase difference output.

In assembling the optical rotary encoder constructed as described above, first, the light projecting block 2 is housed in the body 11, and this is attached to the body 1 with the bolt 25.
1, then insert the rotary block 3 through the bearing 24 held in the light emitting block 2 and the through hole 19 of the body 11, and then insert the light receiving block 4 into the body 11. End cap knob 12
is inserted into the opening of the body 411, and the thin part 15 formed in the opening of the body 11 is caulked along the tapered part 16 with the conical bending punch 8, thereby integrating the body 11 and the end cap 12. Thereafter, as shown in FIG. 15, a plurality of V-notches 7 are formed in the thin portion 15 to prevent the end cap 12 from rotating against the body 111. Furthermore, a cover 13 is fitted onto the body 11,
A plurality of T & shaped holes are formed around the opening of the cover 13.
The cover 13 is prevented from being removed by fitting the notch 6 into the groove 5 formed on the outer peripheral surface of the body 11.

[Effect of the Invention 1] As described above, the present invention has a light-receiving block that is constructed by integrating the light-receiving element, the phase plate, and the light guide. The advantage is that the relative position with the light guide does not shift, the amount of light received by the light receiving element does not change, the output waveform does not become unstable, and as a result, the rotation speed and rotation direction can be detected accurately. has. In addition, since the light receiving element, phase plate, and light guide are integrated, there is no need to adjust the positions of these components during assembly, and they can be easily inserted into the casing, resulting in high work efficiency. It is something.

[BRIEF DESCRIPTION OF THE DRAWINGS] FIG. 1 is an exploded perspective view showing an embodiment of the present invention, FIG. 2 is a vertical cross-sectional view of the same, FIG. 3 is a cross-sectional view of the steps taken along line X-X in FIG. FIG. 4 is an exploded perspective view of a fixed block used in the above, FIG. 5 is an exploded perspective view of a code wheel and rotating shaft used in the same, and FIG. 6 is an exploded perspective view of a light receiving block used in the same. Fig. 7 is an exploded perspective view of the body and cover of the same as above, Fig. 8 is a longitudinal cross-sectional view of the main parts of the same, Fig. 9 is a cutaway perspective view of the main parts of the same, and Fig. 10 is a longitudinal cross-sectional view of the main parts of the same as the above. , 1st
Fig. 1 is a longitudinal sectional view of the vicinity of the end cap same as above, Fig. 12 is a perspective view showing another embodiment of the light receiving block used in the above, Fig. 13 is a longitudinal sectional view taken along the line Y--Y in Fig. 12, 14
15 and 15 are cross-sectional views showing how to assemble the same end cap and body, FIG. 16 is a partial perspective view seen from the same end cap side, and FIG. 17 is a vertical cross-sectional view showing a conventional example. FIG. 18 is a longitudinal sectional view showing another conventional example. 1 is a casing, 4 is a light receiving block, 21 is a light emitting element,
31 is a hood wheel, 32 is a rotating shaft, 35.36 is a slit, 41 is a light receiving element, 43 is a correction slit, 44 is a phase plate, 45 is a light guide, 61 is a fixing screw, 62 is a support piece, 63 is a position This is an opening for adjustment. Agent Patent Attorney Ishi 1) Chief 7 Figure 10 Figure 11 Figure 12 Figure 13 Figure 17 Old Figure 31

Claims (2)

[Claims] (1) A casing, a rotating shaft with at least one end protruding from the casing, and a code wheel that is formed into a disc shape and rotates with the rotating shaft, and has a large number of slits periodically formed along the circumferential direction of the rotating shaft. A light-emitting element that emits light toward the code wheel, a plurality of light-receiving elements that receive the light transmitted through the slit of the code wheel, and convert it into electrical signals, and a light-emitting element that is interposed between the code wheel and the light-receiving element. A rotary encoder comprising a phase plate in which a correction slit corresponding to a light receiving element is formed, and a light guide interposed between the phase plate and the light receiving element to guide light transmitted through the correction slit of the phase plate to the light receiving element. , a light receiving block is constructed by integrating a light receiving element, a phase plate, and a light guide.
An optical rotary encoder characterized in that a light receiving block is fixed at a fixed position within a casing by a fixing means. (2) The fixing means consists of a fixing screw with a sharp tip that is screwed into one end of the casing, and a support piece that is provided at a fixed position in the casing and holds the light receiving block between the tip of the fixing screw. An optical rotary encoder according to claim 1, characterized in that the optical rotary encoder comprises: