JPH0653352B2 - Shock device shock absorber - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for shock-damping a recoil of a striking tool in a striking mechanism such as a rock drill or breaker.

[Conventional technology]

In an impact mechanism such as a rock drill or a breaker, a reciprocating piston impacts an impact tool such as a rod or a chisel to transfer energy and perform work. When a striking tool strikes a work object such as rock or concrete, the striking mechanism receives a shock due to the reaction. In order to buffer this shock, a shock absorber provided with a deceleration piston and a deceleration chamber after the housing of the chuck of the impact tool (JP-A-51-116101).
However, since the piston operating pressure oil is used as the pressure oil for the deceleration chamber cushion, its pulsation has a negative effect, and when the piston is operated at low pressure, it loses the feed force of the striking device and acts as a buffer force. It becomes an unstable device in which the buffering effect cannot be obtained because of the low value.

Therefore, in order to eliminate the fluctuation of the cushion pressure, the conventional third
As shown in the example of the rock drill in the figure, the impact tool (rod 7)
A shock absorber has been used in which a spring 12 is mounted between the support body (chuck bushing 6) that receives the recoil and the cylinder 1 to cushion the recoil.

[Problems to be Solved by the Invention]

However, this shock absorber has a drawback in that the shock absorbing force decreases due to the fatigue and wear of the spring 12 when used for a long period of time, and the shock absorbing force cannot be easily adjusted according to working conditions.

This invention solves the above-mentioned problems in the shock absorber of the striking mechanism, and there is no fluctuation in the shock absorbing force during the work.
An object of the present invention is to provide a shock absorber capable of easily adjusting the shock absorbing force with respect to changes in working conditions and spring characteristics.

[Means for Solving the Problems]

In order to solve the above problems, the shock absorber of the striking mechanism of the present invention includes a piston that reciprocates back and forth in a cylinder, a striking tool that is striking by the piston, and a support body that receives a reaction of the striking tool. In the striking mechanism, a spring, a spring seat, and a spring force adjusting liquid chamber that presses the spring seat toward the spring side with a predetermined pressure are provided between the support and the cylinder.

[Action]

When the piston strikes the striking tool during working and the striking tool strikes the work target, the support receives the impact from the striking tool due to the reaction. This shock is buffered by the spring and transmitted to the cylinder. At this time, since the spring force adjusting liquid chamber presses the spring seat toward the spring with a predetermined pressure, the buffer force of the spring does not fluctuate and a stable buffer operation is performed. When the working conditions change, an appropriate cushioning force can always be obtained by changing the pressure of the spring force adjusting liquid chamber.

〔Example〕

 Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a longitudinal sectional view of a striking mechanism of a rock drill which is an embodiment of the present invention. Here, a piston 2 is fitted and inserted in the cylinder 1, and the piston 2 is reciprocated back and forth (left and right in the drawing) by a hydraulic drive mechanism (not shown). A front head 3, a front cover 4 and a front cap 5 are connected in front of the cylinder 1.
The chuck 7 and the front cap 5 mounted in the front head 3 support the rod 7. A chuck driver 9 having a gear 8 on the outer circumference is fitted between the front head 3 and the chuck bushing 6, and the chuck driver 9 is rotated by a drive gear 10 rotated by a motor (not shown). . A chuck 11 is fitted inside the front of the chuck driver 9, and the chuck 11 spline-engages with the rod 7 to transmit rotation. A spring 12 and a spring seat 13 are mounted between the cylinder 1 and the rear side of the chuck bushing 6. The spring seat 13 has a rear portion having a small diameter to form a spring force adjusting liquid chamber 14 between the spring seat 13 and the front head 3. The spring force adjusting liquid chamber 14 is supplied with pressure oil of a predetermined pressure from an oil passage 15 so that the spring seat 13 13 is pressed toward the spring 12 side. 16 is a thrust washer, 17 is a swivel body,
18 and 19 are plain bearings that support the chuck driver 9, 20 and 21 are plain bearings that support the drive gear 10, and 22 is a thrust bearing.

FIG. 2 is a circuit diagram showing an example of an adjusting pressure oil supply circuit for supplying pressure oil to the spring force adjusting liquid chamber 14. In this regulated pressure oil supply circuit, from the discharge pipe line 24 of the hydraulic pump 23 to the oil line 15 via the switching valve 25, the pressure setting circuits 26, 27,
28 are connected in parallel. Each pressure setting circuit 26, 2
7 and 28 are relief valves 2 having different cracking pressures.
It is composed of 9, 30, 31 and check valves 32, 33, 34, and by switching the switching valve 25, pressure oil of an arbitrary pressure can be supplied to the spring force adjusting liquid chamber 14. Reference numeral 35 is a relief valve of the discharge conduit 24 of the hydraulic pump 23, and 36 is a tank.

During work, the piston 1 strikes the rod 7 and the rod 7
When the work object hits, the chuck bushing 6 receives a shock from the rod due to its reaction. This shock
It is buffered by the spring 12 and transmitted to the cylinder 1. At this time, the spring force adjusting liquid chamber 14 presses the spring seat 13 toward the spring 12 side by the predetermined pressure set by the pressure setting circuit,
The cushioning force of the spring 12 does not fluctuate and a stable cushioning action is performed.
When the working condition changes, the switching valve 25 is switched to change the pressure of the spring force adjusting liquid chamber 14 so that an appropriate buffering force can be always obtained.

〔The invention's effect〕

Since the shock absorber of the striking mechanism of the present invention is configured as described above, there is no fluctuation in the shock absorbing force during work, and the shock absorbing force can be easily adjusted according to changes in working conditions and spring characteristics.
Therefore, the impact that the striking mechanism receives can be reduced and the durability can be improved.

[Brief description of drawings]

FIG. 1 is a longitudinal sectional view of an impact mechanism of a rock drilling machine according to an embodiment of the present invention, and FIG. 2 is a circuit showing an example of an adjusted pressure oil supply circuit for supplying pressure oil to a spring force adjustment liquid chamber. Figures and 3
It is a longitudinal cross-sectional view showing a shock absorber of a conventional striking mechanism. In the figure, 1 is a cylinder, 2 is a piston, 3 is a front head, 4 is a front cover, 5 is a front cap, 6 is a chuck bushing, 7 is a rod, 12 is a spring, 13 is a spring seat, and 14 is a spring force adjusting liquid. It is a room.

Claims (1)

[Claims] 1. A piston that reciprocates back and forth in a cylinder,
In a striking mechanism including a striking tool that is striking by the piston and a support body that receives a reaction of the striking tool, a spring, a spring seat, and a spring seat are provided between the support body and the cylinder. A shock absorbing device shock absorber, comprising: a spring force adjusting liquid chamber that is pressed toward the spring side by pressure.