JPS6032138B2 - Angular displacement/angular velocity detection device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an angular displacement/angular velocity detection device, which detects the angular displacement or angular velocity of a rotating body using the pulse period of light that is repeatedly reflected between a rotating body and a stationary body and made to go around once. The object of the present invention is to provide an angular displacement/angular velocity detection device in which the detection accuracy is not affected even if there are variations in manufacturing precision between the individual light reflecting surfaces of a rotating body and a stationary body. .

For example, various types of rotation detection devices that use magnetism or light are known as rotation detection devices that detect the angular displacement and angular velocity of a rotating body such as a rotating shaft or a rotating plate.

For example, in a rotation detection device using light, as shown in FIG. 1, a slit disk 2 with a slit division angle Δa is attached to a rotating shaft 1 whose rotation is to be detected, and a slit disk 2 is attached as shown in FIG. The light emitting part 3a and the light receiving part 3b of the photocoupler 3 are arranged facing each other across the part where the slit 2a is formed,
The rotational speed of the rotating shaft 1 is detected from a pulse signal having a pulse interval Δ8 as shown in FIG. 3, which is generated in the light receiving part 3b by the slit plate 2 cutting the light beam from the light emitting part 3a. However, the detection accuracy of this kind of conventional angular displacement/angular velocity detection device is largely dependent on manufacturing accuracy such as the shape or dimensions of each slit 2a or the spacing between the slits 2a, and for example, there are variations in the shape and dimensions of the slits 2a. Even if the slit disk 2 rotates at a constant rotational speed, the pulse interval of the pulsed light received by the light receiving section 3b varies, resulting in drawbacks such as the inability to accurately detect angular displacement and angular velocity. there were.

The present invention eliminates the above-mentioned drawbacks, and an embodiment thereof will be described below with reference to the drawings.

FIG. 4 is a schematic vertical sectional view of an embodiment of the angular displacement/angular velocity detection device of the present invention, FIGS. 5 and 6 are perspective views of an embodiment of the rotating ring and stationary ring, respectively, and FIGS. A longitudinal sectional development view of main parts is shown for explaining the optical path between both rings. In FIG. 4, an angular displacement/angular velocity detecting device 11 is used in this embodiment for detecting the rotation of a motor 3 that rotationally drives a capstan shaft 12 of a record player or the like.

The capstan shaft 12 is rotatably supported by a bearing 15 fixed to a substantially central portion of the stator 14, and a disc-shaped rotor holder 16a is fixed in the middle thereof. A ring-shaped magnet 16b is fixed to the rotor holder 16a with a predetermined magnetization on the surface facing the stator, and by applying a predetermined current to a coil 17 fixed to the stator 14, the rotor 16 is rotated at a constant speed. Rotate at speed. Here, the outermost periphery of the lower surface of the rotor holder 16a and the stator 1
A rotating ring 18 and a stationary ring 19 shown in FIGS. 5 and 6 are fixed to the outermost periphery of the upper surface of 4, respectively.
The end faces of 19 face each other. In the case of this embodiment, the rings 18 and 19 have the same shape, and each has a trapezoidal cross-section recess 18n (
18, to 184) and 19n (19, to 194) are drilled in a predetermined number (four in the embodiment) at equal intervals. Recess 18
Two inclined surface portions 18M, 18nb and 19 of n and 19n
Na and 19 ground are both considered to be reflective surfaces that reflect light well. Furthermore, in the case of this embodiment, both rings 18, 1
In order to reflect the light between the end surfaces of 9 and make the reflected light go around without escaping, each reflective surface portion 18na, 18nb (
19na, 19nb) are inclined at a predetermined angle toward the center of the ring 18 (19). Also, the recesses 18n, 19n
The portion other than the inclined surface is a non-reflective surface that does not reflect light. Also, as shown in FIGS. 7 and 8, the recess 19. of the stationary ring 19. A light emitting path 20 and a light receiving path 21 are perforated on both sides of the stay 14, and a light emitting section 22 passing through the two light emitting sections and a light receiving section 23 corresponding to the light receiving section 21 are buried at predetermined positions on the upper surface of the stay 14, respectively. be.

The light beam emitted from the light emitting section 22 is reflected by the reflective surface 20a in the light emitting path 20, becomes a light beam substantially parallel to the bottom surface of the recess 194, and is emitted from the light emitting path 20. Furthermore, the light beam that enters the light receiving path 21 substantially parallel to the bottom surface of the recess 192 is reflected by the reflective surface 21 a in the light receiving path 21 and enters the light receiving section 23 . Here, when the rotating ring 18 and the stationary ring 19 are completely overlapped with each other as shown in FIG.
It then enters the rotating ring 18 perpendicularly, is reflected by one reflective surface 183a of the recess 183, and is reflected by the recess 183.
The ray is parallel to the base of

Then, it is further reflected by the other reflecting surface 183b and enters the recess 193 adjacent to the recess 194. In this way, the light that is bottle-reflected on each of the reflecting surfaces of the recesses 194, 183, 193, 182, etc. travels around the annular space between the rotating ring 18 and the stationary ring 19, and finally passes through the light receiving path. 21
The light passes through the light receiving section 23 and enters the light receiving section 23. In this way, when both rings 18 and 19 are in the positional relationship shown in FIG. , light receiving section 23
The reflective surfaces 19 of both rings 18 and 19 receive light from the light emitting section 22 while the i8nb or the 19 rails 18M are facing each other even slightly.

Next, when the positional relationship between both rings 18 and 19 shifts from the state shown in FIG. 7 to the state shown in FIG. The light beam is reflected by the reflective surface 194b and then reflected by the reflective surface 184b of the rotating ring 18 in a direction opposite to the direction in which the light circulates.

Therefore, the light beam emitted from the light emitting section 22 is transmitted to the concave section 194.
and the concave portion 184, and does not reach the light receiving portion 23. In this way, the light beam received by the light receiving section 23 is interrupted depending on the rotational position of the rotating ring 18, and in the case of a configuration in which four recesses 18n and 19n are provided as in this embodiment, the rotor 16 is 4 while rotating as shown in Figure 9.
The light receiving section 23 receives the pulsed light.

In this way, the light received by the light receiving section 23 is a ray that has gone around the space between the rings 18 and 19, so even if there are variations in the pitch or reflection angle of the individual reflecting surfaces, each pulse is They will be affected by variations uniformly, with no difference in degree. Therefore, information regarding the rotational speed of the rotor 16 obtained from the pulse width or pulse interval of the received light pulses is not greatly distorted by slight manufacturing errors such as the shape or dimensions of the reflecting surface, and therefore, for example, the conventional detection device described above As shown in the figure, the detection accuracy does not deteriorate due to variations in the slit width of each slit 2a of the slit disk 2, and highly accurate rotation detection is always possible.

Further, the rotating ring 18 and the stationary ring 19 can be manufactured accurately and inexpensively by die-casting, for example, and since they have the same shape, a common mold can be used.

In the above embodiment, one ring 18, 19 was provided on the lower surface of the rotor holder 16a and one on the upper surface of the stator 14, but as shown in FIGS.
Rings 18' and 19' having similar shapes to those of rings 18 and 19 and joined to the inner periphery of each ring 18 and 19 are provided, and an optical system constituted by the rings 18 and 19 and the rings 18' and 19 are provided.
The rotor 16 is
It is also possible to adopt a configuration in which the rotation of the sensor is detected in two phases. In the case of this embodiment, rings 18 and 18' (19
, 19') are the recesses 18n and 18'n (19n and 19'n).
) are shifted by about half a pitch, so the pulses obtained from both light receiving sections (not shown) are out of phase by this pitch difference. Therefore, the rotation direction of the rotor 16 can be easily determined from the magnitude of the phase shift between the two pulses. In the case of this embodiment, it is desirable to prevent the two optical systems from interfering with each other, and if it is necessary to reliably prevent interference, between the rings 18 and 18' and between the rings 19 and 19 It is preferable to provide a light-shielding plate (not shown) between '. Furthermore, in each of the embodiments described above, the end surfaces of the rings 18 and 19 or the rings 18' and 19' are arranged to face each other, but for example, the angular displacement/angular velocity detection device 3 shown in FIG.
1, a rotating ring 38 is fixed to the outer periphery of the rotor 16, and a large stationary ring 39 is installed outside the rotating ring 38.
The stationary ring 39 may be held by the stator 14 while the stationary ring 39 is played.

In the case of this embodiment, as shown in FIGS. 13 and 14, a predetermined number (eight) of trapezoidal cross-section recesses 38n and 39n are formed on the inner circumferential surface of the rotating ring 38 and the outer circumferential surface of the stationary ring 39, respectively. . These rings 38, 39 can be easily manufactured by die cutting, taricast molding, etc., and the rings 38, 39 can be obtained with extremely high precision in shape, size, etc.

Also, as in this embodiment, the rings 38, 3 that play each other
9 is also used, for example, as shown in FIGS. 15 and 16,
By constructing rings 38' and 39' having the same shape as the rings 38 and 39, and integrally roughening them by shifting them by a half pitch from each other, the rotor 1
6 rotational speeds can be detected in two phases.

Incidentally, in both of the above embodiments, the rotating rings 38, 38' were made smaller in diameter than the stationary rings 39, 39';
, 38' have a larger diameter than the stationary rings 39, 39',
The rotating rings 38, 38' may be arranged outside the stationary rings 39, 39'.

Further, in each of the above embodiments, each ring 18, 18',
38, 38' and 19, 19', 39, 39' are configured to be inclined, but instead of slanting the reflecting surfaces, for example, as shown in FIG. 17, the light emitting path 20'
By making the light receiving path 21' and the light receiving path 21' oblique by 45 degrees, it is not necessary to form a recessed portion as in each of the embodiments described above.

That is, in the embodiment shown below, the opposing surfaces of the rotating ring 48 and the stationary ring 49 are partially coated with silver, for example, to alternately form reflective surfaces 48n, 49n and non-reflective surfaces 48n, 49n. There is a structure. In this way, the light emitting path 20
Regarding the embodiment of the configuration that changes the shape of the light receiving path 21,
As shown in FIG. 18 and below, a rotating ring 48 and a stationary ring 4
9, various shapes are possible.

Therefore, for those having similar optical path configurations, the reference numeral described in each of the above embodiments is given as a subscript, and the explanation is omitted. These rings 48, 8, 48, 8'
, 48 spots, 48 spots', 49, 9, 49, 9', 4939
, 4939' do not require machining of the recessed portions, and it is only necessary to form the reflective surfaces 48n, 49n and the non-reflective surfaces 48n, 49n separately, so manufacturing is extremely simple. In each of the embodiments described above, the rotating body is not limited to the rotor 16 of the motor, but may be a rotating body such as a rotating shaft.

Furthermore, the number of reflective surfaces formed on the ring is not limited to the embodiment, and may be any other suitable number. As described above, in the angular displacement/angular velocity detection device of the present invention, a stationary body is arranged opposite to a rotating body at a predetermined distance, and a plurality of optical fibers are provided on opposing surfaces of the rotating body and the stationary body, respectively. reflective surfaces are arranged at approximately equal intervals with a predetermined width, and light is incident on the other reflective surface from one of the rotating body or the stationary body, and the light reflected by the other reflective surface is reflected on the other reflective surface. The angular displacement of the rotating body or the period of the pulse obtained by receiving the light that has gone around the rotating body and the stationary body is determined by reflecting the light on the reflecting surface of the rotating body and the stationary body. Since it is configured to detect angular velocity, it is possible to detect variations in the width of each reflective surface, the distance between reflective surfaces, or the reflection angle, and due to variations in each received light pulse.
Since each received light pulse is uniformly affected by the above-mentioned variations in light as it goes around the light, rather than having different effects on each individual pulse, information regarding the rotational speed of the rotating body obtained from the received light pulses is not distorted by manufacturing precision such as the shape or dimensions of the reflecting surface, and therefore the detection accuracy does not deteriorate due to variations in the width of each slit of the slit plate, unlike in conventional detection devices that combine a slit plate and a photocoupler. It has features such as being able to always detect rotation with high precision and being particularly suitable for detecting the rotational speed of the rotor plate without being affected by magnetism in motors that use a rotor plate and a stator plate. .

[Brief explanation of drawings]

Figures 1 and 2 are a perspective view and a side view of essential parts, respectively, of an example of a conventional angular displacement/angular velocity detection device, Figure 3 is a waveform diagram of a light reception pulse of the light receiving part, and Figure 4 is a diagram of the angular displacement of the present invention.・A schematic vertical cross-sectional view of an embodiment of the angular velocity detection device, Figures 5 and 6 are perspective views of an embodiment of the rotating ring and stationary ring, respectively, and Figures 7 and 8 respectively explain the optical path between the two rings. FIG. 9 is a longitudinal development view of the main parts of the present invention, and FIG.
Figures 3 and 14, Figures 15 and 16, Figures 18 and 19, Figure 20
, 21, 22, 23, 24, and 25 are perspective views of modified examples of the rotating ring and fixed ring, respectively, and FIG. 12 is a schematic vertical cross-section of another embodiment of the angular displacement/angular velocity detection device of the present invention. The plan view and FIG. 17 are longitudinal developed views of essential parts for explaining the optical path between both rings of the modified example shown in FIGS. 18 and 19. 11, 31... Angular displacement/angular velocity detection device, 18, 1 8
', 38, 38' 48, 48, 8, 48, 8', 48 spots, 4838'... Rotating ring, 19, 19', 39, 3
9'49,,49,9,49,9',4939,493
9'... Stationary ring, 18M, 18nb, 19na, 1
9nb, 48n... Reflective surface, 22... Light emitting part, 23
······Light receiving section. Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8 Figure 9 Figure 10 Figure 11 Figure 12 Figure 13 Figure 14 Figure 15 Figure 16 Figure 17 Figure 18 Figure 19 Figure 20 Figure 21 Figure 22 Figure 23 Figure 24 Figure 25

Claims (1)

[Claims] 1. A stationary body is arranged to face the rotating body at a predetermined distance, and a plurality of optical reflective surfaces are respectively arranged on opposing surfaces of the rotating body and the stationary body, each having a predetermined width and approximately equal to each other. By arranging the rotary body and the stationary body at intervals, allowing light to enter the other reflective surface from either the rotating body or the stationary body, and causing the light reflected by the other reflective surface to be reflected by the one reflective surface, An angular sensor in which light is repeatedly reflected between the rotating body and the stationary body and made to go around once, and the angular displacement or angular velocity of the rotating body is detected from the period of the pulse obtained by receiving the light that has gone around once. Displacement/angular velocity detection device.