JPS5815273B2 - Separately excited hydraulic impact machine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a separately excited type hydraulic impact machine, and in particular to a separately excited type hydraulic impact machine equipped with a stroke end control device for a drilling tool striking piston when moving from a return stroke to a striking stroke. It is related to.

Hydraulic impact machines that have been put into practical use in the past are self-excited machines that use a spool valve operated by piston displacement to switch the hydraulic pressure applied to a double-acting cylinder and reciprocate the drilling tool impact piston, but they have the following drawbacks. has.

First, since the spool switching cycle is determined by the cycle of the piston reciprocating motion, the number of strikes and the striking energy cannot be changed independently.

That is, if the piston supply fluid pressure is reduced in order to reduce the impact energy, the piston speed will be reduced and the number of hits will also be reduced.

Therefore, it is difficult to perform highly efficient drilling in accordance with geological changes.

Particularly with rotary impact drills, in order to achieve high efficiency drilling by maintaining an optimal combination of drill rotation speed, number of blows, impact energy, and feed characteristics, it is necessary to adjust the rotation speed of the drill in accordance with changes in the number of blows. complex and expensive control schemes must be adopted.

Additionally, there are reports that when the piston hits the drilling tool, it is more efficient to transmit energy to the rock if there is a certain amount of time in which the piston contacts and presses against the drilling tool (hereinafter referred to as "pressing time"). However, there is almost no time for this push.

Furthermore, since it is a self-oscillation type, there is a dead center and it may not start depending on the relative position of the piston and spool when stopped.

In addition, with the aim of achieving high efficiency and incorporating a diaphragm-type accumulator into a bladder to recover the energy of the piston return stroke and use it for the impact stroke, problems arise with the response and durability of the accumulator. For this reason, the number of hits cannot be increased.

On the other hand, a separately excited type hydraulic impact machine uses a spool valve operated by a signal from an oscillator to switch the hydraulic pressure applied to a double-acting cylinder and reciprocates the piston. There were problems with the shock absorption method and it was not put into practical use.

An object of the present invention is to provide a hydraulic impact machine that is highly adaptable to mountains with severe geological changes, has high energy efficiency, and is durable by putting into practical use a hydraulic impact machine using a separate excitation method. .

The present invention provides a hydraulic impact machine of a separately excited type, in which a pressure chamber is installed in the middle of a main flow path connecting a spool valve and an end port on the non-drilling tool side of a pressure chamber on the non-drilling tool side of the cylinder (hereinafter referred to as the cylinder rear chamber). An accumulator and a check valve that prevents the backflow of liquid from the cylinder rear chamber to the spool valve are provided in order from the cylinder rear chamber side, and from the spool valve side of the main flow path and the non-drilling tool side end port of the cylinder rear chamber. A cylinder rear chamber port located closer to the center is in communication with the cylinder front chamber port located closer to the center than the punching tool side end port of a drilling tool side pressure chamber (hereinafter referred to as cylinder front chamber) of the cylinder, and a space between the cylinder front chamber port and the accumulator; By connecting the accumulator through a check valve that prevents liquid from flowing back into the port, the stroke end of the piston is controlled, and a separately excited liquid impact machine is put into practical use.

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

As shown in FIGS. 1 and 2, the hydraulic shock machine of the present invention includes a double acting cylinder 1, an accumulator 2, check valves 3 and 4, a spool valve 5, an oscillator 6, a pump 7, a tank 8, and these are connected. Consists of conduits.

The double-acting cylinder 1 houses a drilling tool striking piston 9 that slides therein, and one end of the piston is configured to strike a drilling tool 10 such as a shank rod.

The piston 9 has two stepped portions 11 and 12, which together with the cylinder wall form a cylinder front chamber 13 and a cylinder rear chamber 14, respectively.

The airtightness of this cylinder is maintained by a piston bearing 15 having an airtight function.

The cylinder 1 is also provided with ports 16 to 23 for liquid inflow and outflow.

Of these, port 16 is located at the end of the cylinder on the drilling tool side, port 23 is located at the end on the non-drilling tool side, and ports 17 and 18 are located at the end of the cylinder on the drilling tool side.
．． 19 is an appropriate position near the center of the cylinder front chamber, po) 2
0,21.22 are located at appropriate positions near the center of the rear chamber of the cylinder.

Open any port in the ports 17 to 22,
The other ports are provided with plugs 24 that can be closed.

FIG. 1 shows the ports 18 and 21 open.

The spool valve 5 is a 2-position, 4-port type, and has a spool 28 having three land portions 25, 26, and 27 inside.
is stored so that it can slide.

The oscillator 6 is for reciprocating the spool 28, and the oscillator and the pilot pressure chambers 29 and 30 of the spool valve are communicated through pipes 31 and 32, respectively.

This oscillator may be of any type, such as electric, hydraulic, mechanical, etc., as long as it can reciprocate the spool 28.

The main pipe connecting the component devices is arranged so that the pump 7 sucks up liquid from the tank 8 and alternately supplies high-pressure liquid to the cylinder front chamber 13 and cylinder rear chamber 14 via the spool valve 5. There is.

That is, a pipe 33 is connected between the tank 8 and the pump 7, a pipe 35 is connected between the pump 7 and the port 34 of the spool valve, a pipe 37 is connected between the port 36 of the spool valve and the port 16 of the cylinder, and the other port 38 of the spool valve is connected. and cylinder ports 20, 21 .
Between 22 and 39 is pipe 39 and pipes 40 and 4L branched from this.
, 42.

Furthermore, a branch pipe 43 is taken out from the pipe line 39, and the check valve 3
, a flow path is formed which reaches the port 23 of the cylinder via the conduit 44.

This check valve 3 is installed to prevent high pressure liquid from flowing back from the cylinder rear chamber to the spool valve.

The pipe 44 and the accumulator 2 are connected by a pipe 45, and the pipe 44 is connected to the cylinder port 17, 18° 19 via the check valve 4 on the other hand to the pipes 46, 4.
Connected by 7.4B and 49.50.

This check valve 4 allows high-pressure liquid to pass through the pipe line 50 (17).
, 18, 19 to prevent backflow.

On the other hand, the ports 5L and 52 of the spool valve are connected to the pipe lines 53 and 5.
4 is loaded with cyan.

Next, the operation will be explained.

FIG. 1 shows a state in which the piston 9 has struck the drilling tool 10 and is about to return.

When the signal pressure from the oscillator 6 is applied to the pilot pressure chamber 29 of the spool valve, the spool 28 starts moving to the right in the figure, and the high pressure liquid flows through the ports 34, 36, the pipe 37, and the port 1.
6 and is supplied to the cylinder front chamber 13.

At this time, the cylinder rear chamber 14 is connected to the port 21 and the pipe line 41.
, 39, ports 38, 52, and conduit 54, the liquid in the cylinder rear chamber 14 is discharged to the tank, and the piston 9 is returned to the right in the figure.

The piston 9 is pushed back to some extent, and its stepped portion 11 reaches the port 18 [, the cylinder front chamber 13 and the cylinder rear chamber 1
4, the liquid in the cylinder front chamber 13 will flow to the port 18.
, the pipes 48 and 46, the check valve 4, the pipes 50 and 44, and the port 23 before flowing into the cylinder rear chamber 14.

At this time, if the port 21 is not yet closed by the stepped portion 12 of the piston 90, this liquid is discharged from the port 21 through the spool valve and into the tank.

Then, when the port 21 is closed, high pressure is applied to both the cylinder front chamber 13 and the cylinder rear chamber 14 due to the action of the check valve 3, and the force that returns the piston disappears.

The piston then returns further to the right due to inertia, and the liquid discharged from the cylinder rear chamber 14 is pushed into the accumulator 2.

This accumulator absorbs the impact of the piston at the end of its stroke and stores the kinetic energy of the piston in the form of potential energy.

In addition, Po N17, 18, 19 and Po) 20, 21
．． The stopper 22 can be positioned at any desired position, and the point at which the force for returning the piston disappears and the operation of the accumulator can be adjusted depending on the operating conditions of the piston.

When the signal from the oscillator 6 changes and signal pressure is applied to the pilot pressure chamber 30 of the spool valve via the pipe 32, the spool 28
(as shown in FIG. 2), high-pressure liquid from the pump 7 is supplied to the cylinder rear chamber 14 via the spool valve.

Since the cylinder front chamber 13 is unloaded when
Piston 9 enters the striking stroke.

Immediately after the start of the impact stroke, the pressure inside the accumulator 2 is higher than the pressure supplied from the pump, so the liquid stored in the accumulator is released into the cylinder rear chamber 14 at once, rapidly accelerating the piston 9.

When the supply pressure and the pressure in the accumulator become equal, the piston moves forward by the force of the supply pressure alone and strikes the drilling tool 10.

By repeating the above steps, the piston continuously strikes the drilling tool.

The hydraulic impact machine according to the present invention can not only be used as a breaker, but also can be used as a rotary impact drill by adding a conventional drilling tool rotation device such as a hydraulic motor.

In this case, even if the impact energy is reduced due to the decrease in the crushing resistance of the rock, the impact can be kept constant independently of this, so as when using a conventional self-oscillating hydraulic impact machine,
There is no need to reduce the rotational speed of the drill using complicated and expensive control using a variable pump, etc., and the entire device can be made simple and inexpensive.

As described above, the hydraulic impact machine of the present invention uses a small number of components to control the stroke end of the piston and uses a separate excitation method, so it is small, lightweight, inexpensive, and highly reliable.

In addition, since the pressure in the front and rear chambers of the cylinder is equalized during the return stroke of the piston, the load on the accumulator is reduced, and shock absorption at the end of the piston's stroke is quickly and effectively carried out, allowing for a high number of blows. It has excellent effects such as

Furthermore, since it is a separately excited system, the number of strikes is determined by the frequency of the oscillator and is independent of the striking energy, making it possible to perform highly efficient drilling in response to changes in rock conditions.

Moreover, since the pressing takes time, the kinetic energy of the piston is efficiently transmitted to the rock.

Furthermore, since the spool is forcibly switched by a signal from the oscillator, there is no dead center and startup is reliable.

[Brief explanation of drawings]

Fig. 1 is a sectional view including a partial piping diagram of a hydraulic impact machine according to an embodiment of the present invention (state at the start of the piston return stroke), and Fig. 2 is similar to Fig. 1 showing the operation of the same embodiment. FIG. 3 is a similar cross-sectional view (state at the start of the piston impact stroke). 1...Double acting cylinder, 2...Accumulator, 3゜4...Check valve, 5...Spool valve, 6...Oscillator, 7...Pump, 8...Tank, 9 ...Drilling tool impact piston, 10...Drilling tool, 13...Cylinder front chamber, 14...Cylinder rear chamber, 16...Drilling tool side end port, 17.18.19... Port from the center of the front chamber of the cylinder, 20.2L, 22... Port from the center of the rear chamber of the cylinder, 23... Port at the end on the non-drilling tool side.

Claims (1)

[Claims] 1. In a separately excited type hydraulic impact machine that reciprocates a drilling tool impact piston by switching the hydraulic pressure applied to multiple cylinders using a spool valve operated by an alternating signal from an oscillator, the spool valve and In the middle of the main channel connecting the end port on the non-drilling tool side of the cylinder rear chamber, in order from the cylinder rear chamber side,
accumulator. A check valve for preventing backflow of liquid from the cylinder rear chamber to the spool valve is provided, and the cylinder rear chamber is located closer to the center from the spool valve side of the main flow path and the non-drilling tool side end port of the cylinder rear chamber. The ports are communicated, and the cylinder front chamber port and the accumulator, which are located closer to the center than the drilling tool side end port of the cylinder front chamber, are connected via a check valve that prevents backflow of liquid from the accumulator to the port. There are also separately excited hydraulic shocks characterized by 2. A cylinder rear chamber port located closer to the center of the cylinder rear chamber than the non-drilling tool side end port, and a cylinder located closer to the center than the cylinder front chamber end port on the drilling tool side. At least one of the front chamber ports is provided in a plurality in the piston traveling direction,
In addition to the excitation type hydraulic shock described in claim 1, which can be selected by a plug etc.