JPH0519428Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to a device for controlling the rotation of an earth drill bucket at the time of starting.

(Prior Art) A conventional rotation control device for an earth drill bucket is constructed as shown in FIG. That is,
A bucket rotation hydraulic motor 5 is installed in the Kelly bar drive device, and its rotational force is generated by the meshing of gears 6 and 7 and the fitting of the square hole 8 provided in the center of the gear 7 with the Kelly bar 4 having a rectangular cross section. The transmission is transmitted to the Kelly bar 4, and the bucket belt 3 attached to the lower end of the Kelly bar 4 is configured to rotate. A control valve 1 consisting of a hydraulically operated three-position switching valve is inserted into the hydraulic circuit of the hydraulic motor 5, and when the operator operates a bucket rotation control lever or the like, the pilot circuit 2a or Pilot pressure oil is supplied to the pressure receiving part 1a or 1b of the control valve 1 via 2b,
By switching the control valve 1 to the left or right position, the bucket 3 rotates forward or reverse.

In such a conventional rotation control device for an earth drill bucket, it is difficult for an operator to control the bucket 3 at will when switching the control valve 1 using an operating lever, etc. , the reversal occurred suddenly,
As a result, a loud collision sound between the Kerryba 4 and the square hole 8 is generated, which makes it difficult to carry out work in urban areas.
There were many complaints from residents.

(Problems to be Solved by the Invention) In view of the above-mentioned problems, the present invention provides an earth drill bucket with a structure capable of preventing the generation of impact noise caused by switching the control valve of the hydraulic motor for rotating the bucket. The purpose of this invention is to provide a rotation control device for

(Means for solving the problem) In order to achieve this object, the present invention is characterized in that a throttle valve is inserted into the pilot circuit of the control valve of the hydraulic motor for rotating the bucket.

(Example) An example of the present invention will be described below with reference to FIG. In the embodiment shown in FIG. 1, flow control valves 11a and 11b each including a variable throttle valve 9 and a check valve 10
are inserted into the pilot circuits 2a and 2b of the control valve 1, respectively. The reason why the check valve 10 is inserted in parallel to the variable throttle valve 9 is to ensure that the flow rate adjustment effect of each throttle valve 9 of each flow rate control valve 11a, 11b appears independently.

With such a configuration, by throttling the variable throttle valve 9, the pressure receiving parts 1a, 1 of the control valve 1 can be reduced.
Since the flow rate of the pilot pressure oil to b is reduced and the movement of the spool becomes slow when switching the control valve 1, the flow rate of hydraulic oil to the hydraulic motor 5 does not increase rapidly but gradually increases. The contact between the square hole 8 of the gear 7 and the Kelly bar 4 is carried out without generating a large impact sound.

Further, in order to increase the effect of preventing the generation of impact noise, fixed throttle valves may be provided in the pilot circuits 2a and 2b, but if a variable throttle valve 9 as shown in the embodiment is provided, the noise becomes less of a problem. In a work place where this is not possible, the throttle amount of the variable throttle valve 9 can be reduced, thereby increasing the flow rate of the pilot pressure oil to perform work, which has the advantage of increasing work efficiency.

(Effects of the invention) As described above, in the present invention, a throttle valve is inserted into the pilot circuit of the control valve of the hydraulic motor for rotating the bucket provided in the Kelly bar drive device, so that the sudden rotation of the hydraulic motor for rotating the bucket can be prevented. Start-up is suppressed, the generation of impact noise at the time of rotation start-up is alleviated, and the excavation work can proceed smoothly without causing trouble with neighboring residents.

[Brief explanation of the drawing]

Fig. 1 is a hydraulic circuit diagram showing an embodiment of the rotation control device for an earth drill bucket according to the present invention;
The figure is a hydraulic circuit diagram showing a rotation control device for a conventional earth drill bucket.

Claims (1)

[Scope of utility model registration request] A rotation control device for an earth drill bucket, characterized in that a throttle valve is inserted into the pilot circuit of a control valve of a hydraulic motor for rotating the bucket.