JPS597266A - Speed detector - Google Patents

Abstract

PURPOSE:To measure the rotating speed of a low-speed rotating body to be measured with high precision, by rotating either of a signal modulator and a receiving part at a known speed and the other at the same speed with the body to be measured, CONSTITUTION:The rotating speed of a motor 11 is known previously and plural slip rings 16-19 are provided to its rotating shaft 12 at specific intervals. A rotating frame 13 is equipped with a light source 7 as a signal source and a photodetecting element 8 as the receiving part which face each other with the the circumferential edge part of a pulse disk 4 inbetween, and they rotate together with the rotating shaft 12 in one body. Then, t=1/(n¦N1+N2¦), where N1 and N2 are the rotating speeds of the body 1 to be measured and motor 11, (n) is the number of pulse cuts of the pulse disk 4, and (t) is the photodetection pulse period of the photodetecting element. In this case, N1 and N2 are different in sign when the body 1 to be measured and motor 11 rotate in the same direction.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a speed detection device, which is also generally called an "encoder," and which detects the speed of an object to be measured, such as a rotating machine. The present invention aims to provide a speed detection device with improved detection accuracy.

FIG. 1 is a perspective view showing a conventional speed detection device of this type.
1) is the object to be measured, such as a rotating machine, housed in the case (2), and (6) is the rotating shaft (3) of the object to be measured (1).
) and the rotating shaft (5) of the pulse disk (4), and the peripheral edge of the pulse disk (4) is provided with transparent portions (4a) of a predetermined width and at regular intervals. and opaque portions (4b) are alternately formed in a striped pattern. (7)
(8) are arranged opposite to each other across the peripheral edge of the pulse disk (4), and are attached to a predetermined position of the support frame (9) adjacent to and fixed to the case (2). A light source consisting of a light emitting diode or the like serves as a signal source, and a light receiving element consists of a phototransistor or the like serving as a receiver.

Since the conventional speed detection device is configured as described above, the pulse disc (4) rotates at the same rotational speed as the object to be measured (1), and the pulse disc (4) is rotated from the light source (7) to the pulse disc (4). The light emitted towards the transparent part (4α) of this pulse disk (4)
Among the opaque parts (4b), the light passes only through the transparent part (4a) and is cut off at the opaque part (4b).
As the pulse disk (4) rotates, the amount of light received by the light receiving element (8) changes in a pulsed manner. Since the transparent parts (4a) and the opaque parts (4b) are formed alternately at regular intervals, the light receiving element (8)
1i: The rotational speed of the rotating measuring object (1) is determined by measuring the light receiving period of this light receiving element (8). Alternatively, it can be determined by counting the number of pulses of light received by the light receiving element (8) in a certain period of time.

However, according to the conventional speed detection device described above,
As the rotational speed of the object to be measured (1) gradually decreases, there is a drawback that the accuracy of measuring the rotational speed gradually deteriorates unless the sampling period for measuring the rotational speed is lengthened.

This invention was made with the aim of eliminating such drawbacks, and it is possible to use either a signal modulator such as the above-mentioned pulse disk (4) or a receiving section such as the above-mentioned light receiving element (8). The device is moved at a speed that can be known in advance, and the other is moved at the same speed as the object to be measured.Even if the speed of the object to be measured is slow, high accuracy can be achieved with a short sampling period. The present invention provides a speed detection device capable of detecting the speed of the vehicle.

That is, although FIG. 2 shows one embodiment of the present invention, the same reference numerals as those in the above-mentioned conventional device (FIG. 1) refer to the same constituent members, and the explanation thereof will be omitted.

QlJ+? - The rotational speed is known in advance, and multiple slig rings a are arranged at predetermined intervals around the rotational axis Q2.
A motor provided with a Q~α field (141 supports this motor 0υ and is attached to a predetermined position on the upper surface of a support frame Q5 which is fixed adjacent to the case (2), 01 is a pulse A light source (7), which is a signal source, and a light receiving element (8), which is a receiving part, are placed facing each other across the peripheral edge of the disc (4), and the motor αp is The rotating frame (231) is a plurality of brushes that are in sliding contact with each of the slip rings aQ to α, respectively, and the input signal to the light source (7) is sent to the brush frame (231). The output signal of the light receiving element (3) is outputted from the slip ring 0Qαη via the brush (221c23).

Since the speed detection device of the present invention is configured as described above, the rotational speed of the object to be measured (1) is now N+ (r,p
, s, ), and the rotational speed of the motor Ql) is N2(r
, p, m, -,), and furthermore, when the rotation direction of the -F liquid distribution measuring body (1) and the rotation direction of the motor α are the same direction, the above N1 and N2 have different signs, and further,
When the number of pulses of the pulse disk (4) is n and the light receiving pulse period of the light receiving element (8) is l (seconds), it is expressed by the above light receiving pulse period l and the object to be measured (1).
The relationship between the rotational speed N1 and the rotational speed N1 is as shown in the characteristic diagram shown in FIG.

Therefore, according to the speed detection device of the present invention, even when the object to be measured (1) rotates at a low speed as described above,
The light receiving pulse period l is long<1. (The effective minimum sampling period ET for rotational speed measurement only needs to be at least 1 light receiving pulse period, so there is no need to make the effective minimum sampling period T'&longer than that, and high accuracy is achieved even at low speed rotation. This has the excellent effect of making it possible to detect the speed of

In the above-mentioned embodiment (Figure 2), the signal source is light, but the signal source may be a signal that can be transmitted and received between each other, such as magnetism, electromagnetic waves, or sound waves. Needless to say, a similar effect can be obtained. Further, this signal source does not necessarily need to be rotated together with the rotating frame α1 as in the above-mentioned embodiment, but as long as the signal source is placed at a position where the receiving section can effectively receive the signal, the signal source may be rotated as shown in FIG. 4. As in the embodiment shown in FIG. It is not necessary to provide this, and the transmitter (25) may be constructed by distributing a signal source made of a permanent magnet or the like on a signal modulator in a pulsed manner as in yet another embodiment shown in FIG. In this figure, (26) is the Hall element corresponding to the transmitting section (2
Alternatively, it is a receiving section such as an electromagnetic transducer consisting of a coil or the like. In addition, the above explanation deals with the case where the receiver is rotated at a rotation speed that can be known in advance, but as in still another embodiment shown in FIG. 6, a permanent magnet or the like is used on the signal modulation. The transmitting unit (25), which has a signal source distributed in a pulsed manner, is rotated at a rotation speed that can be known in advance, and the rotating frame (27) is rotated integrally with the rotation axis (3) of the object to be measured (1). It goes without saying that the same effect as in the above-mentioned embodiment can be obtained even if the receiver (26) attached to the receiver (26) is rotated at the same rotational speed as the object (1) to be measured. Furthermore, the object to be measured (1) is not necessarily limited to a rotating body, and as shown in FIG. In this case, a belt-shaped transmitting section 02 is formed by distributing a signal source made of a permanent magnet or the like in a pulsed manner, which is sent by a roller 01) at a speed that can be known in advance.
The same effect can be obtained even if the signal output from the device 1 is received by the receiver Ce such as an electromagnetic transducer mounted on the object to be measured (2). Although the case where magnetism is used as the source has been described, any signal source may be used as long as it can transmit and receive signals.

As described above, according to the present invention, either the signal modulator such as a pulse disk or the receiving section such as a light receiving element is moved at a speed that can be known in advance, and the other is connected to the object to be measured. Since they are moved at the same speed, even if the speed of the object to be measured is slow, it has the excellent effect of being able to perform high-precision speed detection with a short sampling period.
Not only that, but also the moving direction of the object to be measured can be detected with a single receiving section.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing a conventional speed detection device, FIGS. 2 and 6 each show an embodiment of the present invention, FIG. 2 is a perspective view, and FIG. , is a characteristic diagram showing the relationship between rotational speed of the object to be measured. 4 to 7 are perspective views showing other embodiments of the present invention. In the drawing, (1) is the object to be measured, (3) (5) α is the rotation axis, (4) is the pulse disk, (6) is the coupling, and (7)
) is the light source, (8) is the light receiving element, α is the motor, and α is the light source (
(to) is a slip ring, and (23) is a brush. In addition, the same reference numerals in the figures indicate the same or corresponding parts. Agent Shin Kuzuno - No. IF! 1 412 Fig. 3 Fig. 3 Fig. 4 Fig. 51 Fig. 61171 No. 7 171 Mr. Commissioner of the Japan Patent Office ■, Small Case display Patent application No. 57-117243 2
, name of the invention speed detection device 3, person making the amendment 5, subject of the amendment (li) Column 6 for detailed explanation of the invention in the specification, contents of the amendment (1) in the description, page 6, line 16 and On page 7, line 14, the words ``electromagnetic conversion'' are corrected to ``magnetoelectric conversion.''

Claims (1)

[Claims] moving either a signal modulator that modulates a signal from a signal source or a receiving section that receives a signal modulated by this signal modulator at a speed that can be known in advance;
A speed detection device characterized in that the speed of the object to be measured is detected by moving the other at the same speed as the object to be measured.