JPS62100028A - Two-stage absolute type rotary encoder - Google Patents

Abstract

PURPOSE:To eliminate the need for positioning the home position by using a transmission means to couple the 1st and 2nd rotary encoder representing the absolute position of an encoder shaft or the absolute value of number of revolutions with a code signal. CONSTITUTION:The 1st absolute type rotary encoder (1st encoder) A outputting the absolute position of the encoder shaft 1 within one revolution as a code signal and the 2nd absolute type rotary encoder (2nd encoder) B outputting the absolute value of the number of revolutions of the shaft 1 as a code signal are provided. Then, the 1st and 2nd encoders A, B are coupled by gears 2, 3 whose gear ratio is 1:N. The code signal outputted from the encoders A, B is a BCD code, which are received by D FFs 6-8 through signal lines 4, 5 of the encoders A, B and the signal code of the absolute position and the number of revolution is read.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field of the Invention The present invention relates to an absolute rotary encoder that can detect the positioning of NC machine tools, industrial robots, etc. using absolute positions.

<Summary of the Invention> The present invention provides for one rotation (0 to 360
By combining a first absolute type rotary encoder that indicates the absolute position within the range of This allows absolute position beyond rotation to be detected at all times using a signal code.

<Background of the Invention> Conventionally, absolute rotary encoders have been used to detect the absolute position of NC machine tools and industrial robots. However, even with this absolute encoder, when the shaft rotates more than one revolution,
Without a counter to count the number of rotations and a battery bank-amplified memory to store the number of rotations, it would not be possible to constantly detect the absolute position.

<Purpose of the Invention> The present invention is a two-stage absolute type that can constantly detect the absolute position of the encoder shaft over one revolution using a code signal without the need for a counter or backup memory even after a power outage (at the time of starting work or restarting operation). The purpose is to provide a rotary encoder.

<Configuration and Effects of the Invention> In order to achieve the above object, the present invention provides a first absolute rotary encoder that indicates the absolute position within one rotation (0 to 360°) of an encoder shaft using a code signal; a second absolute rotary encoder that indicates the absolute value of the rotation speed of the encoder using a code signal;
A two-stage absolute type rotary encoder was constructed by connecting through a transmission means with an appropriate transmission ratio.

For example, FIG. 1 shows a first absolute rotary encoder A that outputs the absolute position within one rotation of the shaft 1.
and a second absolute type rotary encoder B that outputs the rotation speed are connected by a gag 3 with a transmission ratio (gear ratio) of N (however, N is an integer of 1 or more), and The number of rotations of the shaft 1 up to N rotations and the absolute position within one rotation thereof can be detected at all times by code signals output from encoders A and B. Note that the resolution at this time is the resolution of the rotation number×1 rotation.

According to the present invention, it is possible to constantly detect the absolute position of the encoder shaft over one revolution even after power is cut off without a counter for counting the number of revolutions or a pantry back amplifier memory for storing it. Therefore, in NC machine tools, industrial robots, and the like, there is no need for calibration (origin position alignment) at the time of starting work or restarting operation, and the present invention has a remarkable effect of achieving the purpose of the invention.

<Description of Embodiments> FIG. 2 shows a two-stage absolute type rotary encoder which is an embodiment of the present invention.

The illustrated example shows one rotation of the encoder shaft 1 (0 to 1 rotation).
The first one outputs the absolute position within 360° as a code signal.
absolute type rotary encoder (hereinafter referred to as “first
A second absolute type rotary encoder (hereinafter referred to as a "second encoder") B that outputs the absolute value of the rotation speed of the shaft 1 as a code signal, and a first encoder A The second encoder B is coupled to the second encoder B by a gear 2.3 with a gear ratio of N. The code signals output by each of the encoders A and B are BCD codes as shown in FIG.
The signal line 4.5 of each encoder A, B is received by a D-type flip-flop 6.7.8, and the signal code of absolute position and the signal code of rotation speed are read.

FIG. 4 shows a second embodiment of a two-stage absolute rotary encoder in which a first encoder A and a second encoder B are integrated into one case 9.

In the illustrated example, each of the first and second encoders A, B
consists of a shaft 1.10, a disk 11.12 on which a pattern is written, and a signal detection section 13.14 for reading signal codes from these disks. A meshing gear 2.3 is installed. Each of the signal detection sections 13.
14 is arranged on a printed circuit board 16, and a signal line 17 for outputting a code signal is drawn out from this printed circuit board 16.

The shaft 1 of the first encoder A is externally connected to, for example, a joint drive unit of an industrial robot, and as the shaft 1 rotates, the first encoder A, the gear 2,
a second encoder B coupled via 3 is activated;
Outputs an absolute position code signal and a rotation speed code signal.

Now - as an example, the resolution of the first encoder A is 360°
, when the resolution of the second encoder B is 7 and the gear ratio of gear 2.3 is 1, in the initial state, the signal code for the rotation speed is "0" and the signal code for the absolute position is ro O.
This is O.J. For example, if the shaft 1 rotates by 1 degree from this state, the signal code for the number of rotations will be "0" and the signal code for the absolute position will be ro OIJ. Furthermore, shaft 1
When rotates 365 degrees, the signal code for the rotation speed is "1",
The signal code for the absolute position is ro05J. When the shaft 1 rotates by 2520° or more, an overflow state occurs.

In the above embodiment, the first encoder A and the second encoder B are coupled by the gear 2.3 to transmit rotation, but this transmission means is not limited to gears, and belts or other devices may be used. is also possible.

[Brief explanation of drawings]

Fig. 1 is a diagram showing the basic configuration of a two-stage absolute rotary encoder of the present invention, Fig. 2 is a diagram showing the configuration of an embodiment of the invention, and Fig. 3 is a diagram showing the signal output waveform of the absolute rotary encoder. The figure shown in FIG. 4 is a diagram showing the structure of another embodiment of the present invention. A...First encoder B...Second encoder ■...Shaft 2.3...Gear Patent applicant Tateishi Electric Co., Ltd./) Prisoner Lm/1aAn4 Untitled 8 Figure attached 2 ＞'Z3 → 廂Ita餉燉织A 应 3) Lu Arrest Explanation 12

Claims (1)

[Claims] A first absolute type rotary encoder that indicates the absolute position within one revolution of the encoder shaft using a code signal, and a second absolute type rotary encoder that indicates the absolute value of the rotation speed of the encoder shaft using a code signal; A two-stage absolute type rotary encoder that combines rotary encoders via a transmission means with an appropriate transmission ratio.