A method and an arrangement for controlling a rock drilling apparatus

(54) (56) (57)

PATENT OY Tampella AB, Tampere Fl

INVENTOR'S OFFICE

NAME

Rauno Rajala, Ylöjärvi Fl, Pauli Rajakallio, AWAPATENT AB

Siivikkala Fl

Method and apparatus for controlling a rock drill

PUBLICATIONS ADDED: - SUMMARY: The invention relates to a method and apparatus for regulating the type and feeding of a rock drill in relation to each other. According to the method, the volume flow in the pressurized liquid to be directed to the percussion device (7) and the supply motor (8) is regulated on the basis of the supply pressure in the feed motor (11) by controlling a volume flow regulated pump (1) so that the percussion device (7) the coming pressure is set in one of the control valves (10, 14) relative to the pressure of the supply motor (11). In the device, pressure fluid is supplied to the percussion device (7) and the supply motor (11) by means of a volume flow regulated pump (I) and to the device there are control valves (10, 14), by means of which the volume flow in the pressure liquid supplied by the pump (1) is kept such that the relationship between the pressures in the impact device (7) and the supply motor (II) is kept substantially constant.

<img file="SE506255C2_D0001.tif" />

<img file="SE506255C2_D0002.tif" />

The numbers in brackets indicate International Identification Code, INID code. Letter Within the pinch indicates international document code.

506 255

The invention relates to a method for controlling the impact power of a pressure fluid driven rock drill, in which method the pressure fluid is simultaneously fed to a impact device and via a pressure reducing means to a feeding device and in which the impact power is controlled by controlling the pressure of the pressure fluid arriving at the impact device.

The invention further relates to a device for controlling the impact power of a pressurized fluid-powered drill, which comprises a pressurized liquid pump, a percussion device and a feeding device, the inlet channel of which is connected to the pump's pressure channel, and at least one pressure reducing means coupled between the pump's pressure channel and the feeding device. pressure fluid to be fed to the supply device so that it is lower than the pressure in the pump's duct.

In known rock drilling machines and in their drive devices, the impact pressure of the rock drilling machine has been determined to a certain value and the drilling machine's feed is regulated by regulating the pressure in the feeding device according to the rock type to be drilled, which often causes difficulties.

Unless the feed pressure is too low in relation to the impact pressure, where the feed rate is lower than the required or permitted feed rate, the pulse is not conveyed properly along the drill rod to the rock to be drilled, but it causes vibration in the drill rod and also in the other equipment. The vibration is eventually converted to heat, with the largest temperature rise occurring in the drill rods or corresponding thread

255 and thus cause especially in these unnecessary loads. As a result, the drilling equipment can be damaged or correspondingly worn faster than usual and thus its operating time becomes shorter, which accordingly increases the operating costs of the equipment. At the same time, the drill penetration rate in stone decreases and the time used to drill a certain hole length is extended, thereby increasing the drilling costs. The vibration also causes extra load in all other mechanical and hydraulic components in the drilling device, and thus in the short term causes an unnecessary service and repair need.

This invention is intended to provide such a method and apparatus for controlling the drilling of the rock drill, with which the above-mentioned difficulties are avoided and the drilling can be performed as best as possible in accordance with the conditions. The method according to the invention is characterized in that the pressure fluid is supplied with a pressure controlled volume flow pump, that the pump volume flow is controlled by the pressure between the supply device and the pressure reducing means and that the relationship between the pressures in the pressure fluids to be fed to the percussion device and to the supply device is controlled so that it is substantially constant. , by means of a pressure regulating means coupled to the feeder device.

The essential idea of ​​the invention is that the relationship between the stroke pressure and the feed pressure is kept substantially constant by controlling the stroke pressure in proportion to the feed pressure, whereby the impact of the pulse pulse is controlled directly according to the pressure level the feed requires and by the use of a pressure controlled volume control pump for the flow of liquid whose volume flow is regulated. on the basis of the feed pressure, whereby the change of the rings in the feed pressure causes changes in the corresponding direction in the impact pressure, since the impact of the stroke is proportional to the volume flow going to the impact machine, thereby keeping the impact pressure and thus the impact effect proportional to the feeding pressure.

The device according to the invention is characterized in that the pump is a pressure controlled volume control pump, that the pressure fluid channel leading to the supply device is coupled to the pump control pressure channel between the pressure reducing means and the supply device, and to which there is at least one pressure control means which is connected to the supply device's inlet channel in series. holding the pressure in the pressure fluid to be passed to the impactor; substantially in a constant relation to the pressure acting in the inlet channel of the feeder.

The essential idea behind the device according to the invention is that the inlet duct of the feed motor is coupled to the control pressure channel of the pressure controlled volume pump, whereby the volume flow of the pump is controlled on the basis of the supply pressure in the supply motor and that it has a pressure control means which maintains the relationship between the feed pressure and the supply pressure.

The invention is described in more detail in the accompanying drawings, in which Fig. 1 schematically shows a coupling embodiment according to the invention and Fig. 2 schematically shows another coupling embodiment according to the invention.

In Fig. 1 there is a volume flow control pump 1 not shown and known per se with a current control cylinder 2 and a spring loaded countercyclist 506.

255

Below 3. Furthermore, a pressure controlled proportional control valve 4 is mounted in the pump. The pump 1 is coupled to suck pressurized fluid from a pressurized fluid container 5 and feed it to a pressure duct 6. The pressure duct 6 is coupled to a percussion device 7, the function and structure of which are generally known in themselves and are not explained in more detail in this connection. The pressurized fluid returning from the percussion device 7 is returned via a return channel 8 to the pressurized fluid container 5. The pressure channel 6 of the pump 1 is further connected via a throttle 9 to a proportional valve 10, from which the pressure fluid is passed on to a supply device 11, which is generally a supply motor, but may also be another supply device such as a pressure liquid cylinder or the like. The pressurized liquid coming from the feed motor 11 is redirected via the return channel 8 to the pressurized liquid container 5. The pressure that arises in the pressure fluid duct between the throttle 9 and the proportional valve 10 is passed along a control duct 12 via a second throttle 13 to a proportional pressure limiting valve 14 and thence to the pressure controlled proportional control valve 4. From the other side of the proportional pressure limiting valve 14, the pressure fluid 8 is guided through the return fluid 8 5th

As the non-shown motor drives the pump 1 in a manner known per se, a pressure exists in the pump's pressure channel, whereby the flowing pressure fluid causes the impact device 7 to function and the feed motor 11 to feed the drilling machine in a known manner. Unless the conditions are kept constant, the pressure in the control duct 12 is also kept constant and thus the function of the pump 1 is not controlled from the outside. The current control cylinder 2 and the spring-loaded counter-cylinder 3, which normally belong to the pump, hold

506 255

1, automatically the volume flow of the pump 1 such that the pressure in the pressure duct 6 is kept constant. The structure and function of the pump 1 and its components stationary to the pump are inherently well known per se and therefore they are not explained in more detail here.

Furthermore, when conditions are constant, pressure fluid flows from the pressure channel 6 through the first choke 9, whereby a loss of pressure occurs in the choke 9. Furthermore, the pressure fluid flows through the proportional valve 10 to the supply motor 11, where in the proportional valve 10 there is a pre-regulated pressure loss independent of the current and thus there is a pressure on the supply motor 11 which is the amount of the total pressure loss of the throttle 9 and the proportional valve 10. in the pressure duct 6 and on the impact device 7. The pressure in the impact device 7 is controlled by a proportional pressure limiting valve 14, which sets the highest pressure in the duct 12. By controlling the pressure limiting valve 14, the pressure prevailing in the duct 12 can be changed and correspondingly increase or decrease the volume flow of the pump 1 and thus the pressure in the pressure duct 6 and on the impact device 7. The control of the pressure limiting valve 14 and the control of the proportional valve 10 are coupled to each other such that as the control value of the pressure limiting valve increases, ie as the value of the maximum pressure of the control channel 12 increases, the control value of the proportional valve 10 decreases correspondingly, whereby a smaller pressure loss arises when the pressure fluid flows and to the feed motor 11 comes a larger feed pressure. The control of the valves is so dimensioned that the pressure of the supply motor 11 and the percussion device 7 is in a linear relationship to each other,

506

255 relationship is essentially constant.

During the drilling, when the drill bit hits, for example, a soft stone or a written, gorge or equivalent, whereby the force which opposes the supply and thus the pressure occurring on the supply motor 11 decreases, at the same time it follows that the pressure between the proportional valve 10 and the throttle 9 decreases. Since the throttle 9 prevents a fast flow of pressure fluid to the supply motor and thus a rush of the feed machine 11 fast forward, it is caused by the reduction of the pressure that the pressure in the control channel 12 accordingly decreases and thereby regulates the position of the control valve 4 and via that of the pump 1 to the volume flow. to quickly become smaller. As the volume flow decreases, simultaneously the pressure in the pressure channel 6 decreases, and thus the impact pressure of the impact device 7 decreases rapidly as the supply pressure drops and in relation to the feed no excessive impact effect and thus conversion thereof into heat occurs. When the drill bit hits a rock or the surface of a rock according to normal conditions, the pressure on the inlet side of the feed motor 11 increases again and correspondingly the pressure between the proportional valve 10 and the throttle 9 increases until it reaches the pressure value to which the pressure limiting valve 14 is adjusted. Similarly, the pressure in the control duct 12 also increases as the pressure between the valve 10 and the throttle 9 increases, thereby regulating by means of the control valve 4 the volume flow of the pump 1 so that it increases to the originally controlled level required by the impact pressure.

Figure 2 shows schematically another embodiment of the invention, in which the impact pressure is not limited to any particular upper limit, but stroke and

506 255 feeds are coupled to each other such that when the pre-regulated pressure ratio prevails, the pressure increase of the feeder motor raises the pressure of the impactor and correspondingly as the pressure drops a pressure drop is produced in the impactor. The figure likewise shows a drive valve 15 for the percussion device with which it can be operated and removed, and a drive valve 16 for the feeding motor, with which the feeding motor can be coupled to feed the drilling machine forward or backward or stop it completely. The function and structure of these valves are known per se and therefore they are not explained in more detail. In this embodiment, only a proportional pressure differential control valve 10 has been used which is coupled to maintain a pressure differential proportional to the feed pressure between the stroke pressure and the feed pressure. In this solution, when the drive valves 15 and 16 are in a normal operating position, the change in the supply pressure in a manner corresponding to the solution according to figure 1 causes a change in the volume flow in the pump 1 so that the pressure in the pressure channel 6 of the pump 1 and thus on the impact device 7 is maintained in the a certain relationship to the feed pressure of the feed engine. In the solution according to Figure 2, the relationship between the stroke pressure and the feed pressure can be controlled by changing the control value of the proportional pressure difference valve 10. If, on the other hand, it is desired to control the stroke pressure level used, it must be done by controlling the bias of the control valve spring 4 in the pump's volume flow control.

Above in the description, embodiments of the invention have been shown by way of example only and the invention is not in any way limited thereto. The essential idea of ​​the invention can be applied by using volume flow pumps which are regulated in different ways and different connections to identify the pressures and

506 255 to connect the control pressure to the volume-regulated pump. The figures and the description have also not shown in general use in different operating and control valves and pressure limiting valves or the like, with which the operation of the device can be controlled and protected in other ways, since these are not essential in the invention. The use of such control, control and protection couplings in no way limits the invention and does not limit its scope of protection. The solution of the invention can, of course, be applied to any other type of use such as controlling the boom of a drilling machine and its components to keep the operating conditions of certain movements proportional to each other.

506 255