JPS61280574A - Apparatus for detecting rotation - Google Patents

Abstract

PURPOSE:To attain the enhancement of accuracy and the miniaturization of constitution, by receiving and transmitting lights having different wavelengths from a plurality of light emitting elements provided in opposed relation to the disc integrally revolved along with a rotary shaft by an optical fiber to process the same. CONSTITUTION:Light emitting elements 3 generating lights having different wavelengths are provided on the disc 1 integrally revolving along with a rotary shaft at 120 deg. intervals so as to opposed to said disc 1. The lights emitted from said elements 3 through the slits 2 of the disc 1 are received by optical fibers 4 to be transmitted to a light distributor 9 as three-fold resolving power lights through a light synthesizer 5 and a main optical fiber 8. The light signal corresponding to the rotational speed of a phototransistor 7 is converted to an electric signal which is, in turn, supplied to each unit 6 to detect a rotational speed. By this method, because the effect of an external field such as a magnetic field or an electric field is not received, the enhancement of accuracy is achieved and the enlargement of harness is also prevented and constitution is miniaturized.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an improvement in a rotation detection device that detects the rotation speed of an engine or the like using an optical signal from a light emitting element.

(Prior Art) Conventionally, as shown in Japanese Patent Application Laid-Open No. 58-22959, one side of this birch rotation detection device is connected to a light source, and the other side detects the rotation speed of a rotating body using an optical signal. Bundle two optical fibers connected to an optical signal processing device, make them face a disk connected to a rotating shaft, and provide a reflector sandwiching the disk and facing these optical fibers, It is known that an optical path is formed in the disk so that the light beam projected from the one optical fiber is reflected by the reflecting mirror and introduced into the other optical fiber.

(Problems to be Solved by the Invention) However, the conventional rotation detection device described above is a single-phase type in which there is one light source for the rotating body, and the light source is a light emitting element that produces 20 pulses per rotation. In this case, the resolution is only about 7 cm per pulse, so it is not sufficient to meet the demands for higher precision that come with the application of various control devices such as four-wheel steering systems and anti-lock brakes to vehicles. The problem was that I couldn't do it.

Therefore, it is conceivable to increase the resolution to about three times (approximately 2CI11>) by increasing the conventional one light source to three, using a three-phase type that uses a plurality of signals.

However, in this case, there are problems in that three optical fibers are required to correspond to the three light sources, which complicates the structure and increases cost.

On the other hand, in order to reduce costs, it is possible to receive the optical signal from the light emitting element with a photodiode, convert it into an electrical signal, and send the signal via electric wire, but in the case of a three-phase type This method is not suitable for practical use because it requires three wires, which causes the harness to become bulky, and also because the signal is easily affected by electric fields, magnetic fields, etc. during transmission, and the accuracy of the sensor becomes a problem.

The present invention has been made in view of the above points, and its purpose is to combine a plurality of optical signals from light emitting elements, each of which emits light of a different wavelength, using a photosynthesizer to create a single optical fiber. By transmitting optical signals as they are through
The purpose of this invention is to improve accuracy without being affected by disturbances such as magnetic fields and electric fields, and to prevent enlargement of the harness and reduce costs.

(Means for Solving the Problems) In order to achieve the above object, the solving means of the present invention provides a plurality of discs arranged above a disc connected to a rotating shaft, each emitting light of a different wavelength as a velocity signal. a light emitting element, a plurality of optical fibers facing each of the plurality of light emitting elements with the disk in between, and connected to the plurality of optical fibers,
a photosynthesis device that combines optical signals from each of the light emitting elements;
It is constructed by a single optical fiber that transmits the combined signal from the optical combining device to the optical signal processing device.

(Function) With the above configuration, in the present invention, optical signals of different wavelengths are emitted from the light emitting elements arranged at intervals of the same phase on the disk, and the multiple optical signals are transmitted through the disk. The light emitting elements are guided to a photosynthesizing device through optical fibers corresponding to the light emitting elements, and are combined. This composite signal is then transmitted as an optical signal to an optical signal processing device through a single optical fiber.

(Example) Hereinafter, an example of the present invention will be described in detail based on the drawings.

FIG. 1 shows the overall configuration of a rotation detecting device according to an embodiment of the present invention, in which numeral 1 denotes a disc drive-coupled to a rotating shaft (not shown), and the disc 1 includes a plurality of discs along the circumferential direction. Drilling hole 2
, 2... are provided.

Reference numeral 3 designates light emitting elements disposed above the disk 1 along the circumferential direction with the same phase, that is, shifted by 120 degrees, and each light emitting element 3 emits light of a different wavelength as a speed signal. It is made to emit. Reference numeral 4 denotes three optical fibers arranged below the disk 1 so as to sandwich the disk and face each of the light emitting elements 3, and each of the six optical fibers 4 is connected to a photosynthesis device 5. The optical signals from each light emitting element 3 are combined in the photosynthesizing device 5.

The above-mentioned photosynthesis device is connected to each unit 6 of a four-wheel steering device, an anti-lock brake device, and an automatic adjustment suspension device by an electric wire 1o.
It is connected to a phototransistor 7 by an optical fiber 8. The optical fiber 8 includes a single main optical fiber 8a extending from the optical combiner 5 to the optical distributor 9, and a sub optical fiber branched into three at the optical distributor 9 and extending from the optical distributor 9 to each of the phototransistors 7. It is composed of a fiber 8b. Thereby, the composite signal synthesized by the photosynthesizing device 5 is transmitted to each phototransistor 6 as an optical signal via the single main optical fiber 8a.

Next, to explain the operation and effect of the above embodiment, as shown in FIG. , are sent to the photosynthesizing device 5 via the optical fibers 4 corresponding to the protruding holes 2 of the disk 1 and each of the light emitting elements 3 at a constant phase interval, and are combined at the photosynthesizing Vt station 5 to produce each of the above. This results in a composite optical signal having three times the resolution of optical signals A, B, and C. This combined optical signal is then distributed by an optical distributor 9 via a single main optical fiber 8a, transmitted as an optical signal to a phototransistor 7, converted into an electrical signal by the phototransistor 7, and then sent to an electric wire 10. It is transmitted to each unit 6 by.

In this way, the optical signals A, B, emitted from the light emitting element 3,
C is synthesized by the photosynthesis device M 5 F and transmitted as an optical signal to the phototransistor 6 via the optical fiber 8.
It is not affected by electromagnetic induction noise due to magnetic fields, electric fields, etc. during transmission, and accurate detection signals can be obtained, improving the accuracy of the sensor. Furthermore, the above-mentioned combined optical signal RI includes each optical signal A from the three light emitting elements 3, 3.3,
B.

Since it is a signal obtained by synthesizing C, its resolution can be increased by about three times, and the sensor accuracy can be further improved.

Furthermore, since the combined optical signal from the photosynthesizing device 5 is transmitted via a single main optical fiber 8a, the structure is simple and inexpensive, and there is no need to use many electric wires. The number of harnesses can be reduced and the enlargement of the harness can be prevented.

Further, FIG. 3 shows another modification of the present invention, in which the optical fibers 4 and the photosynthesizing device 5 disposed facing each of the light emitting elements 3 may be integrated into a unit. Not only can the same functions and effects as in the embodiment described above be achieved, but also the arrangement of the optical fiber 4 can be omitted, resulting in a simpler structure.

<Effects of the Invention> As described above, according to the present invention, a plurality of light emitting elements that emit light of different wavelengths as speed signals are disposed on a rotating body, and the optical signals from the respective light emitting elements are synthesized to generate a composite signal. Since the signal is transmitted as an optical signal through a single optical fiber, an accurate detection signal can be obtained without being affected by electromagnetic induction noise such as magnetic fields or electric fields during transmission.
In addition to improving the 4 degree angle, the number of harnesses can be reduced by eliminating the need for electric wires, preventing the harness from becoming bloated, and
The structure is simplified and costs can be reduced.

[Brief explanation of the drawing]

1 and 2 show a rotation detection device according to an embodiment of the present invention, FIG. 1 is a diagram showing the overall schematic configuration, FIG. 2 is a diagram showing an optical signal as a speed signal, and FIG. 3 is a diagram showing an optical signal as a speed signal. The figure shows the main parts of another modification. DESCRIPTION OF SYMBOLS 1...Disk, 3...Light emitting element, 4...Optical fiber, 5゛・Photosynthesizer, 7...Phototransistor, 8
...Optical fiber, 8a... Main optical fiber. ' 1

Claims (1)

[Claims] (1) A plurality of light-emitting elements arranged above a disc connected to a rotating shaft and each emitting light of a different wavelength as a speed signal, and a plurality of light-emitting elements each facing the plurality of light-emitting elements with the disc in between. an optical fiber, a photosynthesizing device that is connected to the plurality of optical fibers and combines optical signals from each of the light emitting elements, and a single optical fiber that transmits the combined signal from the photosynthesizing device to an optical signal processing device. A rotation detection device characterized by: