FI67603B - ROTATIONSSLAGBORRMASKIN - Google Patents

Description

I55r ^ l M (f1) KUU, LUTUSJULKAI * U sn, n-, jggHA lJ Vi utlAcgningsskrift o / oU0 HS *? C (45) r-.ior.ttl myZr-AA.y 11 M 1? C5 ^ ^ (51) K * Jt / tacCL3 E 21 C 3/20 ENGLISH —FINLAND (21) P »wnttlh« k «mii * —PM «nttn« & lmtnj 750785 (22) —Amöknktpd »* 18.03.75 (23) ΑΜαιρβΜ — Glttighatsdag 18.03.75 (41) Tellut JufldMkal— MM» offutMg ^ g gg y £

Pitant and register required · NlhttvttoifMnon μ kuL | uflc »iMn date. - .. 19 o /.

Patent- och reghterttyralaen AmMunuthgdod «utLikmtwi pubUcurut ΙΔ · 0Η (32) (33) (31) · * nrf« ttjr «uolkuM — Bufird prtorttut (71) L i nden-Ali mak AB, 931 03 Skelleftea, Sweden SE) (72) Sven Granholm, Skelleftea, Sweden-Sweden (SE) (71+) Oy Kolster Ab (54) Rotating machine - Rotationss1agborrmaskin

The present invention relates to a rotary impact drill for drilling stone, concrete or the like with a machine housing, a tool socket for receiving a drill rod, a hydraulic rotary motor, a hydraulic impact motor in a housing with an e-reciprocating impact piston limiting the a high-pressure and low-pressure side, a hydraulic circuit for a rotary motor, which circuit is separated from the hydraulic circuit of the shock engine and which also has a high-pressure and low-pressure side, and a distribution valve in the hydraulic circuit of the shock piston.

Such so-called separately rotatable rock drills have been previously known. They have a rotating motor for rotating the drill rod mounted on the side of the impact motor.

Depending on the characteristics and placement of the rotary motor, a gear transmission is required between it and the drill rod. This gives the rotor a speed and torque that depends on the characteristics of the rotary motor.

The percussion motor has a reciprocating piston which, when accelerated by a pressure fluid, strikes the end of a drill rod, and one or more valves for distributing the pressure fluid to the pressure spaces limited by the piston. When a liquid with a very low compressibility compared to gases is used as the pressure medium, pressure accumulators are required for the high pressure line and possibly also for the low pressure line. The purpose of pressure accumulators is to keep the pressure as constant as possible in the supply and discharge lines and in the ducts of the machine.

The impact and rotary motors of a rock drilling machine generally have separate hydraulic circuits, each comprising at least one pump, a pressure relief valve, a directional valve and the supply and discharge lines of the motors. The filter and the oil tank, on the other hand, may be common.

Rotary motors for rock drilling machines usually have a fixed volume. Adjusting the fluid flow changes the speed of the motors. Impact motors also generally have a fixed or constant volume, but impact motors are also known in which the relationship between the stroke frequency and the fluid flow can be changed by changing the stroke length.

The pressure in the high pressure line of the rotary motor is proportional to the torsional resistance of the drill rod. When drilling hard, homogeneous rock types, the required torque is relatively small and so is the working pressure. This is because when drilling hard rock types, the penetration of the drill rod is mainly due to the impact energy, while the rotation of the drill rod, on the other hand, only rotates the crown at a certain angle between each two successive strokes. In most rock types, the optimum angle of rotation of the port relative to the penetration of the drill can be found for each impact.

Since the optimum value of the rotation angle changes greatly with the properties of the rock types, it is advantageous to be able to adjust the rotation speed of the drill rod in relation to the impact frequency. This can be achieved with a flow control valve in the hydraulic circuit of the rotary motor or a control volume pump.

When drilling soft rock, the rotational movement of the drill or drill rod also directly contributes to the penetration of the drill rod. However, the frictional resistance between the stone and the drill bit is then higher due to the fact that the penetration of the blade, i.e. the drilling depth, increases by 3 67603 in each stroke. As a result, the required torque increases and therefore the working pressure of the rotary motor.

If the drill suddenly enters an area containing soft or cracked rock when drilling hard and uniform rock types, the risk of the drill getting stuck is high due to the rapidly increasing torsional resistance. The combination of shocks and the high torque that occurs can create such stresses that the drill rod will break.

The risk of entrapment can be greatly reduced by reducing the impact energy transferred by the piston to the drill rod during impact. The impact energy can be adjusted by adjusting the stroke length and / or working pressure of the piston. In previously known constructions, the stroke length can be changed by replacing some components of the machine with others or by adjusting the adjusting screw by hand with a special tool. It is clear that these measures cannot effectively prevent the drill rod from sticking.

It is further known that, in order to avoid entrapment, the drill can, with a muscle-controlled valve, restrict or completely shut off the supply of pressure medium to the impact motor or reduce the supply force.

Today, a drill often has three or four machines to handle at the same time, and the risk of drilling is therefore considerably greater than before, when the drill only handled one or possibly two machines.

In practice, however, manual measures have in most cases proved to be too slow to prevent entrapment. Pulling out a stuck drill rod is very cumbersome and labor and time consuming. Besides, it hurts the time for the u-wall to be forced to leave the drill in the hole because it could not be removed with the available tools.

In order to solve the problems associated with screw drilling, a method is known in which the hydraulic circuits of a rotary motor and an impact motor are connected in series. The fluid first flows through a rotary motor, where it releases part of its pressure energy to rotate the drill, and then further through an impact motor, where the rest of the pressure energy is used. Since the same current flows through both motors, this prevents the adjustment with respect to the impact and rotation described above, which is desirable when drilling rock types with different properties. If, on the other hand, an overflow valve is placed between the motors, which allows a certain adjustment of the ratio by allowing a certain part of the flow 4 67603 to flow over the low pressure side, the efficiency of the system deteriorates as the pressure energy of the overflow becomes heat.

Hydraulic circuits in series connection also makes it impossible for issuing the rotation of conventional engines, the use of a rotary motor outlet side of the large paineitten caused by tee-vistysvaikeuksien result.

Another problem when drilling rock occurs in the so-called in long hole drilling. In this form of drilling, you can see that the torsional resistance of the drill gradually increases as the hole is held, while more and more impact energy must be transferred to the drill bit via the long drill rod or rod.

The object of the invention is to provide a rotary impact drilling machine in which e.g. the disadvantages described above have been eliminated and which allows the impact energy to be adjusted automatically so that the risk of drilling is eliminated as much as possible.

Another object is to provide a rotary impact drill in which the impact energy is automatically increased as the torsional resistance increases in long hole drilling.

These and other objects are achieved by a rotary impact drill as defined in claim 1, the preferred embodiments having the features stated in the subclaims.

The invention will be described in more detail below with the aid of the accompanying drawing, in which Figures 1 and 2 show partly schematically two different embodiments of a rotary impact drill according to the invention, Figure 3 also partly schematically shows a modification of the machine of Figure 2 and Figures 4 to 8 schematically show other modifications.

In Figure 1, the machine housing of a rotary impact drill is drawn in solid line 2. A drill 4 is removably mounted in the housing 2. The drill 4 is arranged to be rotated only by a rotational motor 6 shown schematically via a gear 8, 10 and a multi-groove switch 12.

The percussion piston 14 in the cylinder space 16 of the machine housing 2 can move back and forth in the direction of the drill 4. The impact piston 14 is intended to strike the drill 4 as described in more detail below in order to transfer impact energy to it.

5 67603

The impact piston 14 defines a rear annular pressure chamber 18 and a front annular pressure chamber 20 in the cylinder space 16. The rear chamber pressure acts on the piston surface 22 to move the piston in the direction of the drill, working stroke, and the front chamber 20 pressure acts on the piston surface 24 to move the piston away from the drill.

The hydraulic circuit of the rotary motor has a high-pressure line 23 and a low-pressure line 25. In order to open the threaded connections of the drill rod, the rotary motor 6 must be given the opposite direction of rotation by means of a directional valve (not shown).

The rotary motor and the shock motor have separate hydraulic circuits. The hydraulic circuit of the shock motor is supplied with pressure fluid from a high pressure duct 26 to which a pressure accumulator 28 is connected. The hydraulic circuit of the shock motor further has a return duct 27 connected to the pressure accumulator 30. The pressure accumulators 28 and 30 may be of known construction. Ducts 26 and 27 generally lead to a spool valve-type distribution valve 32 with a slide 33. The function of the distribution valve is to connect both pressure chambers 18 and 20 via lines 29 and 31 alternately to high pressure passage 26 and exhaust passage 27, as described in more detail below. the chamber 18 is connected to the high pressure duct 26, at the same time the chamber 20 is connected to the low pressure or return duct 27. The pressure of the liquid in the chamber 18 gives the piston 14 an accelerating forward movement. When the piston collides with the drill rod 4, the chamber 20 is connected to the high pressure channel 26 and the chamber 18 to the low pressure channel 27, whereby the piston moves backwards. The valve slide 33 is hydraulically controlled in the other direction as the pressure fluid enters through the passage 36 at 34 with the impact piston 14 acting as a control valve as described in more detail below. The valve slide 33 is also controlled in the opposite direction hydraulically when the pressure fluid enters via the line 40, in which case the control valve, generally indicated at 42, then acts as a control valve.

The control valve 42 has a valve slide 44 which can move axially in the cylinder space 46 and is loaded in the other direction by a compression spring 48 acting on its end. The compression force of this spring can be adjusted by an adjusting screw 50. At one end of the slider 44 there are two separate pressure chambers 52 and 54. the pressures each act on their own slide surface with the force of the spring 48 with the opposite force. The chamber 54 communicates directly via the channel 55 6 67603 with the high pressure line 26 and the chamber 52 communicates via the channel 57 with the high pressure side of the hydraulic circuit of the rotary motor 6, i.e. to management 23.

The cylinder space 46 of the control valve 42 has a plurality, in the example shown, four annular grooves 60, 62, 64, 66, each connected in its own channel to respective openings 68, 70, 72, 74 formed axially in succession in the wall of the cylinder chamber 20. The slides 44 have grooves 60 , 62, 64, 66 a flattened conical constriction 76.

When the chamber 20 is connected by a distribution valve through the passage 31 to the high pressure line 26, the pressure fluid forces the piston 14 backwards as described above. Each opening 68, 70, 72, 74 is then sequentially exposed below the piston 14 at the piston surface 24 and enters the chamber 20. The high pressure fluid then enters the respective grooves 60, 62, 64 and 66 of the cylinder space 46 and from the cylinder space 46 through the passage 40 to the control pressure inlet 38 of the manifold 32. The manifold slider 33 then moves to another position so that chamber 18 is connected to line 29 and high pressure line 26 through manifold. At the same time, the line 31 is connected to the return line 27 and the piston 14 changes the direction of movement. The stroke length of the piston 14 is thus determined from the openings 68, 70, 73, 74 by the one which first connects the distribution valve of the chamber 20 to the cylinder space 46 via a corresponding groove 60, 62, 64 or 66.

This in turn depends on the difference between the force of the spring 48 on the slide 44 and the opposite force caused by the sum of the pressures in the chambers 52 and 54. The control valve is so dimensioned that the slide 44 cannot close the groove 66, so that this connection gives the piston 14 the maximum stroke length. The return movement of the piston originates from the fact that during the working stroke, the surface 22 of the piston exposes the line 36 in the mouth chamber 18, so that the high pressure in this chamber is applied to the control valve inlet 34 and thus the position of the slider 33 is changed. The piston 14 further has an annular recess 78. A passage 80 permanently connected to the low pressure passage 27 via the manifold ensures that the manifold is emptied by the annular recess 78 so that the passage 80 is connected alternately to the opening 74 and the passage 36.

It can be seen from the above that as the pressure increases in one or both of the high pressure channels of the rotary motor or the shock motor, the stroke length of the piston 14 shortens, while the stroke frequency increases. As the pressure decreases, the stroke length of the piston 14 increases and the stroke frequency decreases. When drilling homogeneous and uniformly hard rock types, the pressure in the high pressure channel 23 of the rotary motor is determined by the torsional resistance of the drill rod 4. During operation, a pressure prevails in the high pressure channel 26 of the shock motor, which gives the slide 44 a corresponding position and a stroke length assigned to the shock motor. If the torsional resistance of the drill rod increases, then the pressure in the high pressure channel 23 of the rotary motor increases. Through the passage 57 and the cylinder space 52, the pressure increase causes the slide 44 to move, as a result of which the stroke length of the piston 14 is shortened and thus the impact energy is reduced. The stroke length and with it the impact energy increase correspondingly as the torsional resistance decreases. The impact energy of the drilling machine is thus adjusted automatically and depends on the torsional resistance of the drill rod, which in turn depends on the type of rock. The stroke length can also be adjusted manually with screw 50.

The device described works regardless of changes in the viscosity of the oil and the degree of wear of the machine. Because the shock motor is operated by a constant volume pump, the fluid pressure corresponds to a certain stroke length and a certain stroke frequency. If the pressure decreases due to a decrease in viscosity or an increased leakage oil flow due to wear, the position of the slider 44 automatically changes, thereby increasing the stroke length of the piston and thus avoiding a decrease in the impact energy. Since the rotary motor and the shock motor are supplied by separate hydraulic circuits, their frequency can be individually adjusted by adjusting the fluid flow of each motor. The conical constriction portion 76 of the slider 44 successively provides a connection between the grooves and thus a stepless adjustment of the stroke length.

The slider of the control valve can also be arranged so that the pressure in the high pressure channel of the shock motor tends to prolong the stroke length of the piston. This embodiment is suitable when the hydraulic circuit of the shock motor is equipped with a separate pressure control valve (constant pressure control). The stroke length adjustment can also be made dependent on the pressure in the high pressure duct of the rotary motor as well as the manual setting. Of course, the number of annular grooves in the cylinder space 46 is not limited to the number shown, but can be both larger and smaller.

In the embodiment shown in Figure 2, the slide 44 of the control valve 42 has an annular recess 90 through which the two grooves 92 and 94 in the wall of the cylinder space 46 can be connected to each other. The groove 92 is connected to the control pressure inlet 38 of the manifold valve 32 by a line 40 of 67603 and the groove 94 is connected to the high pressure line 26 of the hydraulic circuit of the shock motor.

This embodiment differs from the embodiment of Figure 1, so that the current instead of the piston stroke of the working chamber 18 becomes the high pressure side of the rotary drive and the percussion pressure depending on the engine of the hydraulic circuit. The operation of the device also takes advantage of the fact that, despite the presence of pressure accumulators, there is a variable pressure in the hydraulic circuit of the shock motor. These pressure variations depend on the interrelationships between the capacity of the hydraulic pump used to supply the hydraulic circuit of the shock motor, the volume of the shock motor, and the flow losses in the valves and ducts. The device shown operates in a more specific manner as follows.

In the situation shown, the distribution valve 32 is in the position that the high pressure line 26 communicates with the pressure chamber 18, so that the shock piston 14 performs the working stroke. The hydraulic fluid in the chamber 20 then exits through the distribution valve 32 to the low pressure line 27. During the working stroke, the pressure in the high pressure line 26 decreases continuously due to the volume of the chamber 18, so that the pressure in the pressure chamber 54 of the control valve decreases and the slider 44 shifts between the grooves 92 and 94. the connection is lost. At the end of the stroke, the piston surface 22 exposes the mouth of the line 36 flowing into the chamber 18 and the pressure in the chamber 18 acts on the control pressure inlet 34 to the manifold valve, changing position by connecting the high pressure line 29 to the chamber 20 and the low pressure line 31 to the chamber 18. During the return stroke, the pressure in the high pressure line 26 increases and the piston 14 disconnects from the chamber 18 to the control pressure inlet 34. When the increasing pressure in the high pressure line 26 and control valve chamber 54 reaches a certain level, the slider 44 reopens the connection between the grooves 92 and 94. 40 and through the control pressure inlet 38 to the distribution valve so that its position is changed while the piston 14 has completed its return stroke. This will start a new work stroke.

The pressure in the high pressure ducts of both motors thus tends to move the slide 44 against the force of the spring 48 so that the connection between the high pressure duct 26 and the control duct 40 is opened. The impact energy delivered by the impact piston is determined by the working pressure of both engines. If the preload of the spring 40 is increased by the adjusting screw 50, a higher pressure is required in the high pressure passage 26 to move the slider 44 to a position where the passage 26 communicates with the passage 40 through the grooves 92 and 94, provided that the torque resistance remains unchanged. At the same time, this higher working pressure gives the piston 14 more impact energy. If the torsional resistance of the drill (tango) increases, the pressure increases in the high pressure channel of the rotary motor, which also means an increase in pressure in chamber 52. Then a correspondingly lower pressure is required in chamber 54 to move the slider 44 so that the grooves 92 and 94 communicate. A decrease in working pressure causes a decrease in impact energy. Correspondingly, the working pressure required for the shock motor increases as the torsional resistance decreases and thus also the impact energy delivered. That is, the pressure in the pressure chamber 52 determines where at the point of the pulsating pressure curve of the line 26 the connection to the control pressure inlet 38 is opened.

The impact energy of the drilling machine is thus adjusted automatically and depends on the torsional resistance of the drill rod, which in turn depends on the type of rock. Since the rotary motor and the shock motor are supplied via separate hydraulic circuits, their frequency can be separately adjusted by adjusting the fluid flow of each motor, as was also the case in the first embodiment.

The slider of the control valve can also be arranged so that as the pressure in the high pressure duct increases, this pressure increase tends to close the connection between the high pressure duct and the control duct to the control pressure inlet of the distribution valve. This connection can also be arranged to depend on the position of the percussion piston.

The modification of the embodiment of Fig. 2 shown in Fig. 3 has the same mode of operation as the previous one and differs only slightly from it in terms of the connection technical solution, in which the distribution valve and its connections are shown in a little more detail. The pressure in the high pressure line 26 controls the distribution valve in both directions, i.e. the control pressure inlet or duct 34 is permanently connected to the high pressure line 26 by line 100, while the control pressure inlet 38 is connected to it via control valve 42 as before. However, the distributor valve slide has end diameters of different diameters. In addition, the pressure fluid is discharged from the control pressure inlet 38 through a line 102, connections 104 and 106 of the cylinder space 16 and a ring recess 108 in the piston 14, and a line 110 to the low pressure line 27.

10 67603

As in the embodiment of Figure 2, in the modification of Figure 3, pressure fluctuations occur in the high pressure channel 26 due to the pulsating flow through the shock motor. Appropriate sizing of lines, pressure accumulators and ducts can, as in the embodiment of Figure 2, affect the curve of this pulsating flow.

The embodiments described above can also be applied to other types of rock drills, e.g. those in which the second pressure space is continuously connected to the high pressure channel or in which there are other auxiliary valves in addition to the control valve. Such an auxiliary valve can be, for example, a pressure relief valve for the shock motor, which can be integrated with the slider of the control valve or made completely separate. An automatic throttle can also be used in the high pressure duct of the shock motor.

Figures 4 to 8 schematically show examples of such and other modifications.

Figure 4 illustrates the embodiments disclosed in Figures 2 and 3 of a variant in which the impact motor of the hydraulic circuit chor-pressure side of the high pressure can be remote controlled. The control valve 42 has a pressure chamber 120 at the adjacent end of the compression spring 48. The pressure in the chamber 120 acts on the surface 122 of the slider to co-operate with the pressure of the spring to move the slide 44 to the right. Connected to the chamber 120 is a pressure line 124 through which the pressure in the chamber 120 can be adjusted to adjust the pressure in the high pressure passage 26 required to open the connection between the grooves 92 and 94. The combination formed by the pressure chamber 120 and the pressure line 124 can completely completely replace the spring 48 and the adjusting screw 50. Even in the embodiment of Figure 1, the combination of Figure 4 can be used.

Figure 5 shows an embodiment in which the pressures of the high pressure lines of both hydraulic circuits act in reverse on the slide 44. This modification, although shown as applied to the device of Figure 2 or 3, may also be considered in the embodiment of Figure 1. In the device of Figure 5, the increase in pressure in the high pressure channel of the rotary motor causes it to tend to close the connection between the grooves 92 and 94. This embodiment can be used in long hole drilling, where the length of the hole causes a gradually increasing torsional resistance and increased pressure in the high pressure channel of the rotary motor. However, this increased pressure also causes an increase in the pressure in the high pressure line 26 required to open the connection between the grooves 92 and 94, and with it an increase in the impact energy. This increase in impact energy is required in order to transfer sufficient impact energy to the drill bit through the long drilling equipment used. When applied to the embodiment of Figure 1, a corresponding structure would increase the stroke length of the piston and thus also its stroke energy.

The embodiment shown in Fig. 6 differs in principle from the embodiments of Figures 2 and 3 in that the percussion piston in its rear position acts as a valve which bypasses the control valve connecting the control pressure inlet 38 to the high pressure line 26. For this purpose there are two annular grooves 130, 132 to the high pressure line 26. In addition, the piston has an annular recess 134. With the shock piston in its rearmost position, the recess 134 connects the two grooves 130 and 132 to each other so as to open a connection to the control pressure inlet 38 regardless of the system pressure. The chamber 20 is in continuous communication with the high pressure line 26, but the piston surface 24 in the chamber 20 is smaller than the piston surface 22 in the chamber 18. If the control valve 42 opens the connection between the grooves 92 and 94 before the piston reaches its rearward position during the return stroke shortening.

Figure 7 shows an example of a pressure relief valve, in this case built in connection with a control valve 42. To this end, in addition to the grooves 92 and 94, the control valve has a groove 140 which communicates with the low pressure passage 27. In addition, the chamber 18 is in continuous communication with the high pressure passage 26, whereby the piston surface 24 is larger than its surface 22. If the pulsating pressure in the high pressure passage 26 during the return stroke of the piston were to rise too much, the connection between the grooves 92 and 94 would be opened, which would immediately cause a pressure drop in the high pressure passage 26 because it is connected to the low pressure passage 27.

In the schematic modification of the embodiment of Figure 6 shown in Figure 8, the control valve 42 acts as a high pressure dependent throttle valve for line 26 for the pressure fluid supplied to the chamber 18 through the manifold. For this purpose, a groove 92 is connected to the distribution valve as shown instead of the control pressure inlet 38. As the pressure increases in the high pressure line 26 and thus in the chamber 54, the flow cross-section of the groove 94 decreases due to the displacement of the slider 44 to the left.

Claims (10)

1. Rotary impact drill with a machine housing (2), a tool seat for receiving a drill rod (4), a hydraulic rotary motor (6) / a hydraulic impact motor with a reciprocating piston (14) in the housing, which limits the working chamber for its stroke and return stroke, a hydraulic circuit for the stroke motor, which has a high-pressure and a low-pressure side, a hydraulic circuit for the rotary motor (6), which is separated from the hydraulic circuit of the stroke motor, and which likewise has a high-pressure and a low-pressure side. , and with a distribution valve in the hydraulic circuit of the percussion piston (14), through which the working chambers (18, 20) of the percussion motor can alternately be connected to its hydraulic circuit, characterized in that there is a further one through a control input to the high pressure side (23). control valve (42) connected by the hydraulic circuit of the rotary motor (6), which is connected by a control input (54, 55) to the high pressure side (26) of the stroke motor hydraulic circuit and by an output (40) connected to the advantage The control valve (38) of the valve (32), whereby the connection between said output and the corresponding input can be opened and closed by a valve slide (44) in the control valve (42) depending on the pressure on the high pressure side (23) of the rotary motor and the pressure in the The control valve (38) of the distribution valve (32) and thus the working pressure of the percussion engine determining the supply of pressure fluid to the percussion piston (14) via the distribution valve (32) is controllable in a manner known per se, depending on the pressure on the high pressure side of the rotary motor. Rotary impact drill according to claim 1, characterized in that there is further a control valve (42) connected to a high pressure side (57) of the hydraulic circuit by the rotary motor (6), which can be coupled for continuous control of the stroke of the piston (14). between the radial openings (68, 70, 72, 74) arranged in the wall of the working piston (20) for the return stroke (14) and a control thread (38) of the distribution valve (32), the radial openings (68, 70, 72, 74) can be covered from the output of the control valve (42) and individually connected to each of the radial openings control channels by a valve element (44) of the control valve (42), depending on the pressure on the high pressure side of the rotary motor (6). 67603 Drilling machine according to claim 1, characterized in that the control valve (42) is a pressure limiting valve (92, 140) for the impact motor. 4. Drilling machine according to claim 1 or 3, characterized in that the valve element (44) of the control valve (42) in the form of a slide limits two valve chambers (52, 54), one of which (52) is connected to the high pressure side. (23) of the rotary motor (6) and the second chamber (54) is connected to the high-pressure side (26) of the impact motor, and that the slide (44) is loadable to actuate the volume of the chambers (52, 54) through an adjustable pressure device (48). , 50; 124, 120). 5. Drilling machine according to claim 4, characterized in that both chambers are for increasing or decreasing the volume of one valve chamber (52) and for simultaneously decreasing or increasing the volume of the other valve chamber (54) respectively. one end of the slide (44). 6. Drilling machine according to claims 1 and 3 ... 5, characterized in that, for connecting the control valve (38) of the distribution valve (32) to the high pressure side (26), independently of the control valve (42), the baffle (14) of the stroke motor for forming a valve (130, 132, 134) present in its rear region provided with a thread (134) and the inner wall of the motor housing is provided with a pivot lock (130, 132). Drilling machine according to claim 2, characterized in that the radial openings (68, 70, 72, 74) in the wall of the working chamber (20) for the return stroke of the impact piston (14) are connected to annular rafters (42) arranged in the control valve (42). 60, 62, 64, 66), which can be covered by the sliding-shaped valve member (44) of the control valve (42) under the high pressure side (23, 57) of the rotary motor. 8. Drilling machine according to claim 7, characterized in that the valve slide (44) has a conical part (76) tapered in the direction of actuation between the cylindrical end portions in the region of the latch (60, 62, 64, 66). the slide-loading pressure device (48, 50? 124, 120). 9. A drilling machine according to claims 4 and 5, characterized in that the thrust (44) of the control valve (42) acting on the pressure device consists of a compressible spring (48) which can be pre-tensioned by a nut (50).