JPH0413501B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a rotary encoder that transmits two types of pulse signals having mutually different phases as the swivel base rotates, and determines the direction of rotation of the swivel base based on both of the pulse signals. The present invention also relates to a swivel work vehicle which is provided with a circuit for detecting a rotation angle, and is provided with a device that automatically stops the swivel base at a set position based on information from the circuit, thereby improving the operability and efficiency of swing work.

Conventionally, in the above-mentioned swivel type work vehicle, when the detection circuit incorrectly detects the rotation direction and rotation angle due to an electrical problem such as a disconnection in the rotary encoder, the swivel base does not automatically stop at the installation position and the operator's intention is not met. However, there was a risk of causing an accident by turning too far or suddenly stopping even though the set position had not yet been reached.

An object of the present invention is to prevent unexpected situations caused by electrical troubles in the rotary encoder by improving a pulse signal processing circuit from the rotary encoder.

A characteristic configuration of the present invention is that, in the above-mentioned swing type work vehicle, a counter is provided to detect the number of generated pulses at each set time for each of the two types of pulse signals from the rotary encoder, and information from the counter is provided. Based on this, a comparison circuit is provided to detect whether the difference in the number of detected pulses between two types of pulse signals is larger than a set value, and based on the information from the comparison circuit, the difference in the number of detected pulses is determined. The reason is that an alarm device is provided to automatically notify when the value is higher than a set value, and its functions and effects are as follows.

In other words, the comparison circuit detects when the difference in the number of pulse signals transmitted per set time between the two types of pulse signals, which are transmitted in approximately the same number during normal times, has become larger than the set value, which is the maximum allowable number of errors during normal times. As a result, it is possible to detect the occurrence of an electrical trouble such as a disconnection in the rotary encoder, and based on the detection result, an alarm system automatically notifies the operator of the occurrence of an electrical trouble. Promptly take appropriate action against misdetected rotation angles, and
By being able to reliably prompt the operator, we were able to avoid unexpected situations caused by problems with the rotary encoder, and the safety of the automatic turning stop operation was greatly improved.

Next, embodiments will be described based on the drawings.

As shown in FIG.
A boarding operation unit 4 and a driving unit 5 are provided on the swivel base 2, and an excavation bucket 7 is attached to the tip of a work arm 6 that can be freely rotated and rotated. The excavating work device 8 constructed as shown in FIG.

As shown in FIG. 2, a gear supported on the swivel base side that interlocks the hydraulic motor 3 with a swivel drive gear 10 that engages with an internal gear 9A formed on a swivel race 9 fixed on the machine base side. In the speed reduction mechanism 11, a rotary encoder 12 that continuously transmits two types of pulse signals having different phases as shown in FIG. 4 as the speed reduction mechanism 11 rotates is connected to the intermediate shaft 11A. A rotation state detection circuit 13 is provided which detects the rotation angle θ of the swivel base 2 with respect to the machine base and the rotation directions R and L by comparing both pulse signals from the swivel operation lever 14. Potentiometer 1 for detecting operation direction and operation amount
5 is attached.

When the manual automatic changeover switch 16 is switched to the manual side, the swivel base 2 is moved at a speed and in a direction commensurate with the operating state of the lever 14 based only on the information from the potentiometer 15. When the operation valve 17 for the hydraulic motor 3 is automatically operated so as to rotate the hydraulic motor 3, and the changeover switch 16 is switched to the automatic side,
Based on the information from the potentiometer 15 and the rotation state detection 13, the swivel base 2 is moved at a predetermined speed with the lever 14 operation being the activation command.
Further, an automatic swing control device 19 is provided which automatically operates the operation valve 17 so as to rotate it in a direction commensurate with the direction in which the lever is operated, and to automatically stop the operation valve 17 at a position θf set artificially by the setting device 18. In addition to the artificial turning operation performed only by lever operation, automatic turning stop is also possible, thereby improving the operability and efficiency of the turning operation.

As shown in Figures 2, 3, and 4,
The counters 21A and 21B each detect the number of generated pulses of the two types of A-phase and B-phase pulse signals transmitted from the rotary encoder 12 at intervals of time T set by the timer 20. The circuit 13 is connected in parallel to the rotary encoder 12, and the counters 2
Number of both detection pulses input from 1A and 21B n _A ,
Detects whether the difference between n _B (Δn = |n _A −n _B |) is larger than the set value Δn _MAX , which is the maximum allowable number of errors during normal operation, and detects the number of detected pulses n _A , n Comparison circuit 2 that gives a signal to the buzzer alarm device 22 to activate it when the difference Δn of _B is larger than the set value Δn _MAX
3 to notify the operator of electrical troubles such as disconnection of the rotary encoder 12 at an early stage.
This is designed to prevent unexpected accidents during automatic turning stop control due to erroneous detection of the rotation angle θ and rotation directions R and L caused by this trouble.

It should be noted that various improvements can be made to the specific circuit configuration of the comparison circuit 23 that compares the magnitude of the difference Δn between the number of generated pulses n _A and n _B of both pulse signals and the set value Δn _MAX , and the specific comparison calculation flow. Further, the specific value of the set value Δn _MAX can also be changed as appropriate depending on the time T set by the timer 20 and the like.

Further, the alarm device 22 that automatically operates based on the information from the comparison circuit 23 can be of various types such as a buzzer or a flashing lamp. A device for stopping the swivel base 2 in an emergency manner may be provided.

[Brief explanation of drawings]

The drawings show an embodiment of the swivel type work vehicle according to the present invention, FIG. 1 is an overall side view of the excavation work vehicle, FIG. 2 is a schematic system diagram showing the operation structure of the swivel table, and FIG. 3 is a diagram showing the number of generated pulses. FIG. 4 is a flow sheet for determining whether the difference is appropriate or not, and is a diagram showing two types of pulse signals transmitted from the rotary encoder. 2...Swivel base, 12...Rotary encoder,
13...Detection circuit, 19...Automatic stop device, 21
A, 21B...Counter, 22...Alarm device,
23... Comparison circuit, n _A , n _B ... Number of detected pulses,
Δn...difference, Δn _MAX ...setting value, T...setting time.

Claims (1)

[Claims] 1 A rotary encoder 12 that transmits two types of pulse signals with mutually different phases as the rotating base 2 rotates.
is provided, and based on the both pulse signals, the swivel base 2
Circuit 1 for detecting rotation directions R, L and rotation angle θ of
3, and a device 19 for automatically stopping the swivel base 2 at a set position θf based on information from the circuit 13, wherein two types of pulse signals from the rotary encoder 12 are provided. , counters 21A and 21B are provided to detect the number of generated pulses at each set time T, and the counter 2
A comparison circuit 23 is provided to detect whether the difference Δn between the number of detected pulses n _A and n _B between the two types of pulse signals is larger than the set value Δn _MAX based on the information from 1A and 21B, The rotating work vehicle is equipped with an alarm device 22 that automatically notifies based on information from the comparison circuit 23 that the difference Δn in the number of detected pulses is larger than the set value Δn _MAX .