Control device for punching machine

Abstract

Provided is a control device for a drilling machine that prevents hole bending and excessive tightening of the threaded portion of a transmission member in long-hole drilling and large-diameter drilling using a top hammer type drilling machine. 【Solution means】When drilling a breakthrough hole for a long hole, the control device for the drilling machine according to the present invention subtracts the feed pressure of the feed mechanism according to the number of MF rods added. As the number of added MF rods increases, the axial load acting on the bit increases. When each mechanism of the drilling machine is operated in this state, excessive rotational torque may be generated between the bit and the rock mass, leading to excessive tightening of the threaded portion. However, by subtracting the feed pressure, it becomes possible to reduce the axial load acting on the bit, preventing excessive tightening of the threaded portion.

Description

Technical Field

[0001] The present invention relates to a control device for a drilling machine that strikes a tool at the tip of a rod to break rock formations or the like.

Background Art

[0002] As shown in FIG. 1, in a drilling machine 1, a guide shell 4 is provided at the tip of a boom 3 of a traveling carriage 2, and a rock drilling machine body 5 is provided on the guide shell 4 so as to be movable forward and backward by a feed mechanism 6. An MF rod 7 is attached to the rock drilling machine body 5, a threaded portion is provided at the end of the MF rod 7 and can be added, and a bit 8 is attached to the tip of the MF rod 7. A rod changer 9 and a rod magazine 10 are provided on the side of the guide shell 4.

[0003] As shown in FIG. 2, the rock drilling machine body 5 is provided with a known striking mechanism 50 including a striking piston 51 and a valve (not shown), and a known rotating mechanism 52. The rock drilling machine body 5 is provided with a shank rod 53, a dual damper mechanism 54 (Patent Document 1) including a pushing piston 55 and a damping piston 56, and a chuck driver bush 57.

[0004] The rock drilling machine body 5 transmits the striking force generated by the striking mechanism 50 and the rotational force generated by the rotating mechanism 52 to a shank rod 53, an MF rod 7, and a bit 8 (hereinafter collectively referred to as "transmission members") to break a rock formation R to be broken. Then, the rock drilling machine body 5 is constantly pushed toward the rock formation R by the feed mechanism 6 shown in FIG. 1, and the bit 8 penetrates into the inner part while breaking the rock formation R to drill a blast hole BH.

[0005] In the rod magazine 10 shown in Fig. 1, a plurality of MF rods 7 are accommodated, and a rod changer 9 conveys the MF rods 7 between the drilling axis of the rock drill body 5 and the rod magazine 10 to perform the operations of adding and disconnecting. Thereby, in the drilling machine 1, it is possible to drill the blasting hole BH of the long hole to the deep part of the rock mass R. The MF rod 7 has a male thread formed at the tip and a female thread formed at the rear end.

[0006] Generally, there are two types of drilling machines: the "down-the-hole type" in which the striking mechanism directly strikes the rear end of the bit, and the "top hammer type" in which the striking mechanism strikes the rear end side of the transmission member.

[0007] Although the down-the-hole type drilling machine is suitable for increasing the hole diameter and is less likely to cause hole deviation, since the striking mechanism operates in the hole, there are size limitations, and since the driving method of the striking mechanism is generally pneumatic drive, it is difficult to increase the output power. Therefore, there is a limit to improving the drilling speed and energy efficiency.

[0008] The top hammer type drilling machine has a hydraulic drive for the striking mechanism and is higher in output power and efficiency than the down-the-hole type drilling machine. However, for this reason, in the case of the top hammer type drilling machine, when drilling a large-diameter hole, excessive tightening of the threaded portion of the transmission member may occur. In such a case, since it is necessary to perform non-rotating strikes for loosening the screw for a long time, there is a problem of shortening the life of the transmission member.

[0009] In addition, in the case of the top hammer type drilling machine, when drilling a long hole, hole deviation may occur. Depending on the degree of hole deviation, additional drilling may be required because the planned blasting cannot be performed, resulting in a problem of reduced work efficiency. Furthermore, there is also a problem that partial contact of the threaded portion occurs due to the hole deviation, leading to further shortening of the life of the transmission member.

[0010] Thus, the top hammer type drilling machine and the down-the-hole type drilling machine each have their own advantages and disadvantages. For example, at a work site where large-diameter hole drilling work is required, the down-the-hole type drilling machine is selected, and at a work site where drilling speed is prioritized, the top hammer type drilling machine is selected. However, the emergence of a highly efficient drilling machine with less hole deviation that exceeds this boundary has been awaited.

Prior Art Documents

Patent Documents

[0011]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0012] The applicant of the present application is further promoting higher output and higher efficiency in top hammer type drilling machines, and is intensively researching to enhance the capabilities of the impact mechanism, rotation mechanism, and feed mechanism. In order to appropriately transmit the increased drilling energy resulting from the enhanced capabilities of the drilling machine to the rock mass that is the object to be crushed, it is necessary to optimize the contact property between the bit and the rock mass and the connection state of the threaded portion of the transmission member. However, when excessive thrust is applied by the feed mechanism or the dual damper mechanism, the frequency of occurrence of the above-mentioned hole deviation and excessive tightening of the threaded portion of the transmission member increases, and the resulting malfunction situation may become more serious.

[0013] Therefore, the present invention is made by paying attention to the above problems in a top hammer type drilling machine, and an object thereof is to provide a control device for a drilling machine that prevents hole deviation and excessive tightening of the threaded portion of the transmission member in long hole drilling and large diameter hole drilling.

Means for Solving the Problems

[0014] (First Invention) In order to solve the above problems, a control device for a drilling machine according to the present invention is a drilling machine that performs long hole drilling while adding rods in the direction of the drilling axis, and includes a striking mechanism disposed on the rear end side of the rod to strike the rear end of the rod, a rotating mechanism for rotating the rod around the drilling axis, and a damper mechanism having a pushing action for pressing a bit fixed to the tip of the rod against an object to be crushed. The control device is used for a top hammer type drilling machine including a rock drilling machine body and a feed mechanism for feeding the rock drilling machine body along the drilling axis, and in the control device for controlling the feed pressure of the feed mechanism, the feed pressure is subtracted according to the number of added rods.

[0015] Adding a rod can be regarded as adding a feed thrust corresponding to the mass of a single rod. However, in the present invention, since the feed pressure is subtracted according to the number of added rods, an appropriate feed thrust can be maintained, and excessive tightening of the threaded portion of the rod can be prevented.

[0016] (Second Invention) Further, in a control device for a drilling machine according to an aspect of the present invention, the amount of subtraction of the feed pressure is adjusted so that the rotation pressure is maintained within a predetermined range. According to the present invention, since the amount of subtraction of the feed pressure is adjusted so that the rotation pressure is maintained within a predetermined range, it is suitable for performing control appropriate to the drilling situation.

[0017] In the drilling operation performed while adding rods, the transmission member is exposed to a severe load state as described above. In the second invention, it is assumed that the rotation torque acting on the transmission member has the most influence on the fastening of the screw, and the feed pressure is appropriately controlled by replacing this rotation torque with the rotation pressure and referring to it.

[0018] (Third Invention) In addition, in the control device for a drilling machine according to one aspect of the present invention, the subtraction amount of the feed pressure is adjusted between the upper limit feed pressure at which the threaded portion at the rod connection portion is overly tightened and the lower limit feed pressure at which the pushing action of the damper mechanism stops functioning. According to the present invention, since the subtraction amount of the feed pressure is adjusted between the upper limit feed pressure at which the threaded portion at the rod connection portion is overly tightened and the lower limit feed pressure at which the pushing action of the damper mechanism stops functioning, it is suitable for performing control appropriate to the drilling situation.

[0019] The third invention newly defines parameters such as the upper limit feed pressure at which the threaded portion at the rod connection portion is overly tightened during drilling and the lower limit feed pressure at which the pushing action of the damper mechanism stops functioning, and adjusts the subtraction amount of the feed pressure between the upper limit feed pressure and the lower limit feed pressure. When the thrust of the pushing action is defined as the pushing thrust, usually the relationship is feed thrust > pushing thrust. However, as a result of subtracting the feed pressure according to the number of joined rods, there may be a situation where the feed thrust < pushing thrust and the pushing action stops functioning. The feed pressure at this time is defined as the lower limit feed pressure.

[0020] When the pushing action stops functioning, a so-called "idle drilling state" may occur where the drilling operation is performed in a state where the tip of the bit and the object to be crushed are not in sufficient contact. In the idle drilling state, since the impact energy is not consumed for crushing, an appropriate drilling operation cannot be performed, leading to a reduction in the lifespan of the rod and the rock drill body. Furthermore, since the rotational resistance of the tip portion of the bit decreases, it causes loosening of the threaded portion of the rod. That is, the third invention controls the feed pressure by parameters directly related to the over-tightening and loosening of the threaded portion of the rod.

[0021] (Fourth Invention) Further, in the control device for a drilling machine according to one aspect of the present invention, the subtraction amount of the feed pressure is adjusted such that the subtracted feed pressure exceeds the critical feed pressure at which the piston reaction force associated with the impact and the feed thrust balance out. According to the present invention, since the subtraction amount of the feed pressure is adjusted so as to exceed the critical feed pressure at which the piston reaction force associated with the impact and the feed thrust balance out, it is suitable for performing control appropriate to the drilling situation.

[0022] When the piston moves forward and backward by the impact mechanism, a reaction force acts on the rock drill. The reaction force acting on the rock drill as the piston moves forward is defined as the "piston reaction force associated with the impact". When the thrust of the feed mechanism is the feed thrust, the feed pressure at which the piston reaction force associated with the impact and the feed thrust balance out is defined as the critical feed pressure.

[0023] When the piston reaction force associated with the impact exceeds the feed thrust, the rock drill instantaneously moves backward in the situation where the piston moves forward, and the drilling operation becomes unstable. The fourth invention adjusts the subtraction amount of the feed pressure so that the subtracted feed pressure exceeds the critical feed pressure. Since the feed thrust exceeds the piston reaction force associated with the impact, the rock drill does not instantaneously move backward and the drilling operation does not become unstable.

[0024] (Fifth Invention) Further, in the control device for a drilling machine according to one aspect of the present invention, the damper mechanism receives the supply of damper pressure from the outside and moves forward to apply a pressing force to the rod. When the subtracted feed pressure is lower than the critical feed pressure at which the piston reaction force associated with the impact and the feed thrust balance out, the damper pressure is added. According to the present invention, the drilling machine is provided with a damper mechanism having at least a pushing action for pressing the bit against the object to be crushed. When the subtracted feed pressure is lower than the critical feed pressure at which the piston reaction force associated with the impact and the feed thrust balance out, the damper pressure is added. Therefore, it is suitable for performing control appropriate to the drilling situation.

[0025] As a result of subtracting the feed pressure according to the number of added rods, when the feed pressure falls below the critical feed pressure, in the situation where the piston reaction force associated with the impact exceeds the feed thrust and the piston advances, the jackhammer instantaneously retreats, resulting in unstable drilling operation.

[0026] The fifth invention aims to stabilize the drilling operation by adding the damper pressure when the piston reaction force associated with the impact exceeds the feed thrust. At this time, since the feed pressure is adjusted according to any one of the first to third inventions, the threaded part of the rod will neither be overly tightened nor loosened.

[0027] (Sixth Invention) Also, in the control device for a drilling machine according to an aspect of the present invention, the damper mechanism includes a pressing member that exerts a pushing action inside, and the added amount of the damper pressure is adjusted so that, during the impact cycle, the pressing member is in a position retracted from its forward stroke end. According to the present invention, the added amount of the damper pressure is adjusted so that, during the impact cycle, the member that exerts the pushing action of the damper mechanism is in a position retracted from its forward stroke end, which is suitable for performing control that appropriately responds to the drilling situation.

[0028] The damper mechanism of the drilling machine of the sixth invention includes, as a member that exerts a pushing action, for example, a pushing piston in the case of a dual damper mechanism described later, or a floating piston in the case of a single floating damper mechanism described later. If the added amount of the damper pressure increases and the member that exerts the pushing action reaches its forward stroke end, the pushing action cannot be exerted.

[0029] The sixth invention is to adjust the added amount of the damper pressure so that the member that exerts the pushing action is at a position retracted from the forward stroke end between the impact cycles, thereby keeping the stroke of the member that exerts the pushing action within an appropriate range and stably exerting the pushing action. At this time, since the feed pressure is adjusted according to any one of the first to third inventions, the threaded portion of the rod will neither be overtightened nor loosened. Also, since the damper pressure is adjusted according to the fifth invention, it is possible to properly press the bit against the rock mass and maintain proper drilling work.

[0030] (Seventh Invention) Further, in the control device for a drilling machine according to an aspect of the present invention, it is characterized by including mode selection means for selecting drilling conditions and being able to select a speed priority mode for adjusting the feed pressure based on the upper limit feed pressure. According to the present invention, since the control device includes mode selection means for selecting drilling conditions and can select a speed priority mode for adjusting the feed pressure based on the upper limit feed pressure, it is suitable for performing control that appropriately responds to the drilling situation.

[0031] For the drilling work, it is required that various drilling conditions can be selected according to the state of the object to be crushed. For example, when the object to be crushed is very stable rock mass, it is preferable to select drilling conditions with a high drilling speed. In order to increase the drilling speed, it is necessary to increase the feed thrust. However, if the feed pressure exceeds the upper limit feed pressure defined in the third invention, overtightening of the threaded portion will occur.

[0032] The seventh invention enables the selection of a speed priority mode from among the drilling conditions. The speed priority mode adjusts the feed pressure based on the upper limit feed pressure, enabling the selection of appropriate drilling conditions according to the state of the object to be crushed. Note that excessive tightening of the screw part also depends on the type of rod. For example, since the drill tube described later is very rigid, stress concentrates on the screw part and excessive tightening of the screw part is likely to occur. Conversely, in the MF rod of the bottom drive method described later, stress does not excessively concentrate on the screw part and excessive tightening of the screw part is unlikely to occur. Therefore, the operator will comprehensively judge the state of the object to be crushed and the type of rod and select the mode.

[0033] (Eighth Invention) Further, in the control device for a drilling machine according to an aspect of the present invention, the control device includes mode selection means for selecting drilling conditions, and the mode selection means can select a hole curvature prevention mode for adjusting the feed pressure based on the lower limit feed pressure during the drilling operation. According to the present invention, since the control device includes mode selection means for selecting drilling conditions and can select a hole curvature prevention mode for adjusting the feed pressure based on the lower limit feed pressure, it is suitable for performing control appropriate to the drilling situation.

[0034] It is required that various drilling conditions can be selected depending on the state of the object to be crushed in the drilling operation. For example, when the object to be crushed is unstable rock such as a crushed zone or a cavity, it is preferable that the drilling conditions are such that hole curvature does not occur. In order to avoid hole curvature, it is necessary to reduce the feed thrust. However, when the feed pressure is lower than the lower limit feed pressure defined in the third invention, proper drilling operation cannot be performed and loosening of the screw part of the rod occurs.

[0035] The eighth invention enables selection of a hole curvature prevention mode from among the drilling conditions, and the hole curvature prevention mode adjusts the feed pressure based on the lower limit feed pressure, enabling selection of appropriate drilling conditions according to the state of the object to be crushed. Note that the likelihood of hole deviation is greatly influenced by the type of rod. For example, drill tubes are least likely to deviate, while MF rods and MM rods using the bottom drive method described later are likely to deviate. Therefore, the operator will select the mode by comprehensively judging the state of the object to be crushed and the type of rod.

[0036] (Ninth Invention) Further, in the control device for a drilling machine according to an aspect of the present invention, the control device includes mode selection means for selecting drilling conditions, and in a region where the upper limit feed pressure is higher than the critical feed pressure, the feed pressure is adjusted based on the critical feed pressure, and in a region where the upper limit feed pressure is lower than the critical feed pressure, a hybrid mode in which the feed pressure is adjusted based on the upper limit feed pressure can be selected.

[0037] According to the present invention, the control device includes mode selection means for selecting drilling conditions, and in a region where the upper limit feed pressure is higher than the critical feed pressure, the feed pressure is adjusted based on the critical feed pressure, and in a region where the upper limit feed pressure is lower than the critical feed pressure, a hybrid mode in which the feed pressure is adjusted based on the upper limit feed pressure can be selected. Therefore, it is suitable for performing control appropriate to the drilling situation.

[0038] The ninth invention basically intends to adjust the feed pressure based on the critical feed pressure throughout the entire drilling length, and gives priority to preventing the piston reaction force from exceeding the feed thrust and the rock drill from retreating instantaneously, resulting in unstable drilling operations. Furthermore, in the final stage of drilling where the upper limit feed pressure becomes dominant over the critical feed pressure, the feed pressure is adjusted based on the upper limit feed pressure.

[0039] That is, the ninth invention is suitable for performing drilling operations with a rod that is likely to deviate, such as an MM rod using the bottom drive method, although the state of the object to be crushed is not as unstable as when selecting the hole deviation prevention mode. [Advantages of the Invention]

[0040] As described above, according to the present invention, in the drilling operation using a top hammer type drilling machine, it is possible to prevent hole bending in long hole drilling and large diameter hole drilling and excessive tightening of the threaded portion of the transmission member.

Brief Description of the Drawings

[0041]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

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Figure 14

Embodiments for Carrying Out the Invention

[0042] Hereinafter, an embodiment of the present invention will be described with appropriate reference to the drawings. Note that the drawings are schematic. Therefore, it should be noted that the relationship between the thickness and the planar dimensions, the ratio, etc. are different from the actual ones, and there are also portions where the dimensional relationships and ratios are different between the drawings.

[0043] Also, the embodiments shown below illustrate devices and methods for embodying the technical idea of the present invention, and the technical idea of the present invention does not specify the material, shape, structure, arrangement, etc. of the components in the following embodiments.

[0044] (Structure of the drilling machine) As shown in FIG. 1, in the drilling machine 1, a guide shell 4 is provided at the tip of the boom 3 of the traveling bogie 2, and a rock drill body 5 is provided on the guide shell 4 so as to be able to move forward and backward by a feed mechanism 6. An MF rod 7 is attached to the rock drill body 5, a threaded portion is provided at the end of the MF rod 7 and can be added, and a bit 8 for drilling is attached to the tip of the MF rod 7. In this way, the drilling machine 1 is a top hammer type drilling machine in which the rock drill body 5 is disposed on the rear end side of the MF rod 7 and can perform long hole drilling.

[0045] On the side of the guide shell 4, a rod changer 9 and a rod magazine 10 are provided. Also, at an appropriate position of the traveling bogie 2, a control device 20 including a computer and configured to be able to execute information processing necessary for the drilling operation is mounted. The control device 20 of the present embodiment is capable of executing a feed control process for controlling the feed pressure FP of the feed mechanism 6 described later.

[0046] As shown in FIG. 2, the rock drill body 5 is provided with a known striking mechanism 50 composed of a striking piston 51 and a valve (not shown), and a known rotating mechanism 52. The rock drill body 5 is provided with a shank rod 53, a dual damper mechanism 54 (Patent Document 1) composed of a pushing piston 55 and a damping piston 56, and a chuck driver bush 57.

[0047] As shown in FIG. 3, the rock drill body 5 is provided with a front stage portion 5a, a central stage portion 5b, and a rear stage portion 5c in order from the front in the axial direction to the rear. The dual damper mechanism 54 is connected to the pump P via a high-pressure circuit 5d connected to an external hydraulic pump, and the leaked oil from the sliding contact portion is discharged to the tank T via a drain circuit 5e.

[0048] The upper half of the center line in FIG. 3 shows a state where the dual damper mechanism 54 is stopped at its reference position, that is, a state where the front end of the damping piston 56 abuts on the central stage portion 5b and the rear end of the pushing piston 55 abuts on the front end of the damping piston 56.

[0049] The lower half of the center line in FIG. 3 shows a state where the pushing piston 55 moves forward away from the damping piston 56 and its front end abuts on the front stage portion 5a. With respect to the reference position of the dual damper mechanism 54, the forward stroke amount of the pushing piston 55 is ST1, and the backward stroke amount of the damping piston 56 is ST2. The operating mechanism of the dual damper mechanism 54 is described in detail in Patent Document 1, so the description is omitted here, but it exhibits a pushing action that applies a pressing force to the rod 7 via the shank rod 53.

[0050] Figure 4 shows a single floating damper mechanism 60 that realizes the same pushing action and damping action as the dual damper mechanism 54 with a single piston member (Patent Document 2). As shown in Figure 4, the rock drill body 5' is provided with a front step portion 5a' low-pressure port 63, a high-pressure port 64, and a rear step portion 5c' from the front in the axial direction to the rear, and a floating piston 61 is slidably fitted therein so as to be able to advance and retreat.

[0051] A damper oil chamber 62 is defined between the inner peripheral surface of the rock drill body 5' and the outer peripheral surface of the floating piston 61. The low-pressure port 63 and the damper oil chamber 62 are isolated by a low-pressure side seal length SL(L), and the damper oil chamber 62 and the high-pressure port 64 are isolated by a high-pressure side seal length SL(H).

[0052] In Figure 4, the floating piston 61 shows a state at the reference position in the single floating damper mechanism 60, that is, a state where the tip of the floating piston 61 is at the position of the reference position 5b'. The reference position 5b' is a position where the thrust generated by the feed mechanism 6 and the thrust of the floating piston 61 are balanced.

[0053] The floating piston 61 can advance by a stroke amount ST1' from its front end from the reference position 5b' to the front step portion 5a', and its rear end can retreat by a stroke amount ST2' from the reference position 5b' to the rear step portion 5c'. The thrust of the single floating damper mechanism 60 is determined by the pressure receiving area of the damper oil chamber 62, the low-pressure side seal length SL(L), the high-pressure side seal length SL(H), and the damper pressure. The operating mechanism of the single floating damper mechanism 60 is described in detail in Patent Document 2, so the description is omitted here, but it exhibits a pushing action similar to the dual damper mechanism 54.

[0054] (Type of percussion rod) FIG. 5 is a diagram comparing various rods that can be attached to the same class of drilling machines. (a) shows the MF rod 7, (b) shows the drill tube 107, (c) shows the MF rod 207, and (d) shows the MM rod 307. All of them can be attached to the drilling machine of the present invention.

[0055] The MF rod 7 shown in FIG. 5(a) is a solid MF (Male-Female) type rod in which a male thread 7m1 and a shoulder surface 7m2 are formed on the male thread portion 7m on the front end side, a female thread 7f1 and a rear end surface 7f2 are formed on the female thread portion 7f on the rear end side, and a water hole 7h is formed in the axial center.

[0056] The drill tube 107 shown in FIG. 5(b) is a hollow MF type rod in which a hollow pipe is provided in a central portion (not shown), a male thread 107m1 and a shoulder surface 107m2 are formed on the male thread portion 107m on the front end side, a female thread 107f1 and a rear end surface 107f2 are formed on the female thread portion 107f on the rear end side, and a water hole 107h is formed in the axial center.

[0057] The MF rod 207 shown in FIG. 5(c) is a solid MF type rod in which a male thread 207m1 and a tip surface 207m2 are formed on the male thread portion 207m on the front end side, a female thread 207f1 and a bottom wall surface 207f2 are formed on the female thread portion 207f on the rear end side, and a water hole 207h is formed in the axial center.

[0058] The MM rod 307 shown in FIG. 5(d) is a solid MM (Male-Male) type rod in which male threads 307m1 and both end surfaces 307m2 are formed on the male thread portions 307m at both ends, a water hole 307h is formed in the axial center, and it is fastened by the female thread 307SL1 of the sleeve 307SL.

[0059] The fastening force of the screw is generated between the contact portion of the end faces of the male screw portion and the female screw portion and the thread. The contact portion of the end faces of the MF rod 7 and the drill tube 107 is the shoulder surface 7m2 (107m2) and the rear end surface 7f2 (107f2), and this screw connection is called the shoulder drive method. On the other hand, the contact portion of the end face of the MF rod 207 is the front end face 207m2 and the bottom wall surface 207f2, and the contact portion of the end face of the MM rod 307 is both end faces 307m2, and this screw connection is called the bottom drive method.

[0060] In the shoulder drive method, since stress tends to concentrate on the screw portion, over-tightening of the screw portion is likely to occur due to seizure by heat or the like. In contrast, in the bottom drive method, since the bending is dispersed throughout the rod, stress is less likely to concentrate excessively on the screw portion, and over-tightening of the screw portion is less likely to occur than in the shoulder drive method.

[0061] The difficulty of occurrence of hole bending depends on the bending rigidity of the rod body and the screw connection method. That is, the higher the bending rigidity of the rod body, the less likely it is for hole bending to occur, and the shoulder drive method that receives the bending load on the shoulder surface is less likely to cause hole bending. Therefore, the difficulty of occurrence of hole bending of the rod shown in Fig. 5 is drill tube 107 (least likely to cause hole bending) > MF rod 7 > MF rod 207 = MM rod 307 (more likely to cause hole bending than other methods).

[0062] (Drilling operation) Next, the drilling operation by the drilling machine 1 will be described. The impact force generated by the impact mechanism 50 and the rotational force generated by the rotation mechanism 52 are transmitted to the transmission members, that is, the shank rod 53, the MF rod 7, and the bit 8 to crush the rock mass R that is the object to be crushed. Then, the rock drill body 5 is constantly pushed against the rock mass R by the feed mechanism 6, and the bit 8 penetrates into the inner part while crushing the rock mass R to drill a blast hole BH.

[0063] The rod changer 9 houses a plurality of MF rods 7, and the rod changer 9 conveys the MF rods 7 between the drilling axis of the rock drill body 5 and the rod magazine 10 to perform the operations of adding and disconnecting. As a result, the drilling machine 1 can drill the blast hole BH of the long hole to the deep part of the rock mass R.

[0064] In the drilling operation, it is well-known to execute while variously adjusting the operating conditions of the impact mechanism 50, the rotation mechanism 52, the feed mechanism 6 and other devices according to the drilling state. The applicant of the present application has also made proposals regarding various drilling controls. In the present embodiment, the operating conditions of the impact mechanism 50 and the rotation mechanism 52 are constant, and the operating conditions of the feed mechanism 6 and the dual damper mechanism 54 (single floating damper mechanism 60) will be described as control parameters.

[0065] (Term Definition) Next, the definition of the feed pressure FP related to the control device for a drilling machine of the present invention will be described with reference to FIGS. 6 and 7. FIG. 6 is a conceptual diagram showing the relationship between the drilling length and the feed pressure when using the MF rod 7. The horizontal axis represents the drilling length (m), the vertical axis represents the feed pressure (MPa), and various feed pressures according to the present invention are plotted. In the following description, the "feed pressure FP" means the hydraulic pressure for operating the feed mechanism 6, and the "feed thrust" means the thrust in the drilling direction generated by the operation of the feed mechanism 6. The feed thrust increases and decreases in proportion to the feed pressure FP.

[0066] 〇Upper Limit Feed Pressure (FPup; Feed Pressure Upper Limit) It is the feed pressure FP at which the screw part at the rod addition part is tightened too much. When performing the drilling operation with a feed pressure FP exceeding the upper limit feed pressure FPup, excessive tightening of the screw part at the rod addition part occurs, and it becomes necessary to perform non-rotating impact for loosening the screw for a long time when recovering the rod. As a result, the life of the transmission member is reduced and the working efficiency also deteriorates.

[0067] 〇Lower limit feed pressure (FPlo; Feed Pressure Lower Limit) The feed pressure FP at which the feed thrust becomes smaller than the pushing thrust of the dual damper mechanism 54 (single floating damper mechanism 60) and the pushing action stops functioning. That is, when the drilling operation is performed at a feed pressure FP below the lower limit feed pressure FPlo, as shown in the lower half of the center line in Fig. 3, the pushing piston 55 reaches the forward stroke end, so the pushing action stops functioning.

[0068] When the pushing action stops functioning, a so-called "idle hitting state" may occur where the drilling operation is performed in a state where the contact between the tip of the bit and the object to be crushed is insufficient. In the idle hitting state, since the impact energy is not consumed for crushing, an appropriate drilling operation cannot be performed, leading to a reduction in the lifespan of the rod and the rock drill body 5. Furthermore, since the rotational resistance at the tip of the bit decreases, it causes loosening of the screw part at the rod connection part. If the screw part at the rod connection part loosens during the drilling operation, the impact energy is not properly transmitted at the connection part, resulting in a decrease in drilling efficiency. Furthermore, there is a risk of damage to the screw part and dropout of the rod. Note that when the feed thrust becomes smaller than the pushing thrust, the pushing action does not immediately stop functioning. Actually, it fluctuates under the influence of the rebound from the rock mass R.

[0069] The lower limit feed pressure FPlo is uniquely determined by the specifications of the dual damper mechanism 54 (single floating damper mechanism 60). The lower limit feed pressure FPlo is a region where it is difficult for the feed mechanism 6 to exhibit its original function. In the drilling operation performed at the feed pressure FP adjusted based on the lower limit feed pressure FPlo, the dual damper mechanism 54 (single floating damper mechanism 60) functions to complement the feed mechanism 6.

[0070] 〇Critical feed pressure (FPcr; Feed Pressure Critical Limit) Although details are omitted because they are well-known techniques, the impact piston 51 included in the impact mechanism 50 moves forward and backward when pressure oil is supplied. At this time, a reaction force acts on the rock drill body due to the operation of the impact piston 51. The reaction force acting during the forward movement is defined as the "piston reaction force associated with impact".

[0071] The critical feed pressure FPcr is the feed pressure FP at which the piston reaction force associated with the impact described above and the feed thrust are balanced, and is uniquely determined by the specifications of the impact mechanism 50. When the drilling operation is performed with a feed pressure FP below the critical feed pressure FPcr, the rock drill body 5 instantaneously moves backward when the impact piston 51 moves forward, and the drilling operation becomes unstable. Note that when the feed thrust becomes smaller than the piston reaction force, the rock drill body 5 does not immediately move backward. In reality, it fluctuates under the influence of the sliding resistance of the components.

[0072] 〇 Feed pressure subtraction amount (ΔFP) This is the feed pressure subtracted each time one rod is added, and is uniquely determined by the mass of the rod and the type of the rod. As the number of added rods increases, the mass of the entire rod increases, and the substantial feed thrust also increases. Therefore, it is set to absorb the increase in feed thrust caused by such rod mass. In FIG. 6, the slope of the straight line of the upper limit feed pressure FPup corresponds to the feed pressure subtraction amount ΔFP.

[0073] FIG. 7 is a conceptual diagram showing the relationship between the drilling length and the feed pressure when the drill tube 107 is used. The horizontal axis represents the drilling length (m), the vertical axis represents the feed pressure (MPa), and various feed pressures according to the present invention are plotted. Even when the drill tube 107 is used, the relationship between the critical feed pressure FPcr and the lower limit feed pressure FPlo is the same as that of the MF rod 7.

[0074] On the other hand, the initial value (the intersection with the vertical axis) of the upper limit feed pressure FPup of the drill tube 107 has shifted downward compared to when the MF rod 7 is used, and the interval between the upper limit feed pressure FPup and the lower limit feed pressure FPlo has become narrower than when the MF rod 7 is used. Also, the slope of the straight line of the upper limit feed pressure FPup has increased. That is, it can be seen that the feed pressure subtraction amount ΔFP tends to be larger than that of the MF rod 7. Here, in FIG. 7, in the final stage of the drilling operation, a region where the upper limit feed pressure FPup and the lower limit feed pressure FPlo intersect and reverse appears, and this region is outside the technical scope of Invention 3. In the actual drilling machine 1 (top hammer drill), the drilling operation is performed within the range up to the corresponding drilling length without using this region.

[0075] Although not shown, the slope of the straight line of the upper limit feed pressure FPup when the MM rod 307, which is small in diameter and lightweight, is used is smaller than that of the MF rod 7 and the drill tube 107. Therefore, the intersection position of the upper limit feed pressure FPup straight line and the critical feed pressure FPcr straight line shifts to the right in FIG. 6.

[0076] (Aspects and effects corresponding to each invention) Hereinafter, the aspects of the present invention and their effects will be described. (First invention) When the control device for a drilling machine of the present invention drills the breakage hole BH of the long hole, the control device 20 subtracts the feed pressure FP of the feed mechanism 6 according to the number of MF rods 7 attached. As the number of attached MF rods 7 increases, the axial load acting on the bit 8 increases. When each mechanism of the drilling machine 1 is operated in this state, an excessive rotational torque may be generated between the bit 8 and the rock mass R, and there is a risk of excessive tightening of the threaded portion. By subtracting the feed pressure FP, it becomes possible to reduce the axial load acting on the bit 8 and prevent excessive tightening of the threaded portion.

[0077] (Second invention) The feed pressure subtraction amount ΔFP is adjusted so that the rotational pressure maintains within a predetermined range. As described above, excessive tightening of the threaded portion causes excessive rotational torque between the bit 8 and the rock mass R. Therefore, the second invention can optimally control the feed pressure subtraction amount ΔFP by referring to this rotational torque by replacing it with the rotational pressure of the rotation mechanism 52.

[0078] The "predetermined range" defined in the second invention will be described later.

[0079] (Third Invention) The feed pressure subtraction amount ΔFP is adjusted between the upper limit feed pressure FPup at which the threaded portion of the rod joint is overly tightened and the lower limit feed pressure FPlo at which the pushing action of the damper mechanism stops functioning. The third invention controls the feed pressure by a parameter directly related to excessive tightening and loosening of the threaded portion of the rod, and can control it more optimally than the feed pressure subtraction amount ΔFP.

[0080] (Fourth Invention) The feed pressure subtraction amount ΔFP is adjusted so that the feed pressure FP after subtraction exceeds the critical feed pressure FPcr at which the piston reaction force associated with the impact and the feed thrust balance out. In the fourth invention, since the feed thrust exceeds the piston reaction force, the behavior that the chisel drill instantly retreats does not occur, and the drilling operation does not become unstable.

[0081] (Fifth Invention) When the subtracted feed pressure FP is below the critical feed pressure FPcr at which the piston reaction force associated with the impact and the feed thrust balance out, the damper pressure is added. The fifth invention aims to stabilize the drilling operation by adding the damper pressure when the piston reaction force exceeds the feed thrust.

[0082] (Sixth Invention) The added amount of the damper pressure is adjusted such that, between the impact cycles, the pushing piston 55 (floating piston 61) of the dual damper mechanism 54 (or single floating damper mechanism 60) is in a position retracted from the front stage portion 5a (5a') which is the forward stroke end thereof. The sixth invention is to keep the position of the pushing piston 55 (floating piston 61) within the appropriate range of its stroke and stably exert the pushing action.

[0083] (The seventh invention) The control device 20 is provided with mode selection means for selecting the drilling conditions, and can select a speed priority mode (SP mode) for adjusting the feed pressure FP based on the upper limit feed pressure FPup. The seventh invention aims to improve the drilling speed while preventing excessive tightening of the threaded portion when the object to be crushed is a very stable rock mass R.

[0084] (The eighth invention) The control device 20 is provided with mode selection means for selecting the drilling conditions, and can select a hole deviation prevention mode (PD mode) for adjusting the feed pressure FP based on the lower limit feed pressure FPlo. The eighth invention is to prevent hole deviation and always exert the pushing action when the object to be crushed is an unstable rock mass R, thereby properly transmitting the impact force generated by the impact mechanism 50 to the rock mass R of the object to be crushed and improving the impact efficiency.

[0085] (The ninth invention) The control device 20 is provided with mode selection means for selecting the drilling conditions, and can select a hybrid mode (HB mode) for adjusting the feed pressure FP based on the critical feed pressure FPcr in a region where the upper limit feed pressure FPup is higher than the critical feed pressure FPcr, and adjusting the feed pressure FP based on the upper limit feed pressure FPup in a region where the upper limit feed pressure FPup is lower than the critical feed pressure FPcr.

[0086] The ninth invention basically intends to adjust the feed pressure FP based on the critical feed pressure FPcr throughout the entire drilling length, giving priority to preventing the piston reaction force associated with the impact from exceeding the feed thrust and causing the rock drilling machine body 5 to retreat instantaneously, which would make the drilling operation unstable. On top of that, in the final stage of drilling, the feed pressure is adjusted based on the upper limit feed pressure FPup. That is, although the state of the object to be crushed is not unstable enough to select the hole deviation prevention mode (PD mode), the ninth invention is suitable for drilling operations using rods that are prone to hole deviation.

[0087] Hereinafter, as a control example in the control device for a drilling machine of the present invention, the speed priority mode (SP mode) - hole deviation prevention mode (PD mode) - hybrid mode (HB mode) will be described. Figures 8 to 11 show the number of added MF rods 7 and the control and operating states of various mechanisms of the drilling machine. The horizontal axis represents the number of added rods, and the vertical axis represents the control states of the feed mechanism, rotation mechanism, impact mechanism, and damper mechanism from top to bottom, showing the displacement of the shank rod and the state of absorbed energy associated therewith. In these controls, the rotation pressure, damper displacement, and absorbed energy are not directly controlled. Figure 8 is a comparative example in which the present invention is not implemented.

[0088] (No Control Mode) Figure 8 shows the drilling conditions set when the no control mode (N mode; No Control Mode) is selected as the control mode, and it is attached for comparison with each control mode according to the present invention.

[0089] When the no control mode is selected, the control device 20 sets the drilling conditions as follows. · Feed pressure FP: Set to a value near the middle between the upper limit feed pressure FPup and the lower limit feed pressure FPlo, and maintain the set value. In this embodiment, the feed pressure FP exceeds the upper limit feed pressure FPup at the fifth added rod number. Therefore, excessive tightening of the threaded part occurs at the fifth added rod number. · Rotational pressure: It is adjusted so that the rotational pressure at the initial value (number of added rods: 0) is near the middle of the upper limit value and the lower limit value, and the rotational speed at that time is maintained. Therefore, as the rotational resistance increases, the rotational pressure increases step by step and reaches near the upper limit value at the fourth added rod. Here, the increase width (terrace height) of the rotational pressure is always constant, and furthermore, it is the same as the increase width of the rotational pressure in the hole curvature prevention mode and the hybrid mode described later. · Impact pressure: It is set to maintain a constant value. · Damper pressure: It is set to maintain a constant value. · Damper displacement: It becomes a constant value. · Absorbed energy: It becomes a constant value.

[0090] In this way, the non-control mode is simple to set, but if the number of added rods of the rod exceeds the allowable number, excessive tightening of the screw part will occur. Therefore, when performing long hole drilling, the initial value of the feed pressure FP must also be set low.

[0091] (Speed Priority Mode) FIG. 9 shows the drilling conditions set by the control device 20 when the speed priority mode (SP mode; Speed Priority Mode) is selected as the control mode, and specifically, it is as follows. · Feed pressure FP: It is subtracted by the feed pressure subtraction amount ΔFP based on the upper limit feed pressure FPup. Specifically, it is set to be a value of 85% or more and 95% or less of the upper limit feed pressure FPup. · Rotational pressure: It is adjusted to maintain the upper limit value. · Impact pressure: It is set to maintain a constant value. · Damper pressure: It is set to be added at the seventh added rod, which is the number of added rods when the upper limit feed pressure FPup is lower than the critical feed pressure FPcr. · Damper displacement: A constant value is maintained until the seventh added rod where the damper pressure is added, and it increases at the seventh added rod. That is, the pushing piston 55 moves forward. · Absorbed energy: It is the relationship between the damper displacement and the front and back. A constant value is maintained until the 7th addition, and it decreases at the 7th addition.

[0092] (Hole deviation prevention mode) Figure 10 shows the drilling conditions set by the control device 20 when the hole deviation prevention mode (PD mode; Prevented (hole) Deviation Mode) is selected as the control mode, and specifically, it is as follows. · Feed pressure FP: It is set based on the lower limit feed pressure FPlo. Specifically, it is set to a value of 105% or more and 115% or less of the lower limit feed pressure FPlo. · Rotation pressure: It starts from the lower limit value and is adjusted to increase step by step towards the upper limit value. · Impact pressure: It is set to maintain a constant value. · Damper pressure: It is set to maintain a constant value (a value higher than that in the no-control mode). · Damper displacement: A constant value (a value higher than that in the no-control mode) is maintained. · Absorbed energy: A constant value (a value lower than that in the no-control mode) is maintained.

[0093] (Hybrid mode) Figure 11 shows the drilling conditions set by the control device 20 when the hybrid mode (HB mode; Hybrid Mode) is selected as the control mode, and specifically, it is as follows. · Feed pressure FP: The initial value is set based on the critical feed pressure FPcr. From the 1st to the 6th addition, the critical feed pressure FPcr is maintained, and at the 7th addition, it is subtracted to the upper limit feed pressure FPup. Specifically, it starts from a value of 105% or more and 115% or less of the critical feed pressure FPcr, maintains a value of 105% or more and 115% or less of the critical feed pressure FPcr from the 1st to the 6th addition, and is subtracted to a value of 85% or more and 95% or less of the upper limit feed pressure FPup at the 7th addition. ·Rotational pressure: The initial value is adjusted to be lower than the value in the no-control mode, and it increases step by step towards the 7th added number with the increase of rotational resistance, forming a step at the 7th added number with a smaller rising width than before. ·Impact pressure: Set to maintain a constant value. ·Damper pressure: Add at the 7th added number, which is the added number when the upper limit feed pressure FPup is lower than the critical feed pressure FPcr. ·Damper displacement: Maintain a constant value until the 7th addition where the damper pressure is added, and it increases at the 7th added number. ·Absorbed energy: It has a relationship with the damper displacement, and a constant value is maintained until the 7th addition, and it decreases at the 7th added number.

[0094] (Regarding the upper / lower limit rotational pressure and the upper / lower limit feed pressure) From here, the relationship between the upper / lower limit rotational pressure and the upper / lower limit feed pressure shown in FIGS. 8 to 11 will be described with reference to FIGS. 12 to 14. The following relational expressions are given for the screw nominal diameter D (mm) of the rod and the torque T (Nm), that is, the minimum torque Tmin (Nm) and the maximum torque Tmax (Nm). Tmin = K × Fmin × AS × D ··· Equation (1) Tmax = K × Fmax × As × D ··· Equation (2) K: Coefficient Fmin: Required axial stress (N / mm2) Fmax: Maximum axial stress (N / mm2) As: Screw effective cross-sectional area (mm2) D: Screw nominal diameter (mm)

[0095] Here, the coefficient K is a constant determined by the specifications of the screw, such as the friction coefficient of the screw, the lead angle of the screw, and the size of the seating surface. In the case of a T-screw (trapezoidal screw) commonly used in rock drills, 0.15 < K < 0.25. Also, in the case where the screw portion loosens due to the impact during drilling, the required axial stress Fmin is the minimum axial stress required to maintain the screw connection at the fastening portion of the shank rod 53 - rod 7 - bit 8 (hereinafter referred to as the "transmission member"), and the maximum axial stress Fmax is the axial stress at which the screw connection at the fastening portion of the transmission member is over-tightened and it becomes difficult to loosen it during rod extension and recovery. FIG. 12 is a schematic diagram plotting the relationship with the screw nominal diameter D by calculating the minimum torque Tmin and the maximum torque Tmax from Expression (1) and Expression (2) when using a typical transmission member.

[0096] The following relational expression is given for the rotational pressure Pr (MPa) and torque T (Nm) measured by the rotational pressure gauge of the rotation mechanism 52 of the drilling machine 1 of the present invention. T = V / 2π × (Pr - Pr´) × β × η ··· Expression (3) V: Motor capacity (CC) β: Reduction ratio Pr´: Rotational pressure during idling η: Motor torque efficiency

[0097] The hydraulic motor mounted on the rotation mechanism 52 is a positive displacement hydraulic motor, and the motor capacity V is constant. The hydraulic motor is selected according to the drilling diameter. For example, the motor capacity V is 160 cc, 390 cc, etc. The reduction ratio β is the ratio between the output shaft of the hydraulic motor and the rotational speed of the transmission member. The rotational pressure Pr´ during idling is the rotational pressure measured by the rotational pressure gauge when idling in a non-drilling state, and can be regarded as the pressure loss of the hydraulic passage from the rotational pressure gauge to the tank via the rotation mechanism 52. FIG. 13 is a schematic diagram plotting the relationship between the rotational pressure Pr and the torque T at the motor capacity V.

[0098] The rotational pressure Pr (MPa) of the rotation mechanism 52 of the drilling machine 1 of the present invention and the feed pressure FP (MPa) of the feed mechanism 6 are given by the following relational expression. FP = α × Pr ··· Equation (4) α: Feed coefficient Here, α is a coefficient determined by the rock quality of the rock mass R to be crushed and the diameter of the bit 8.

[0099] Thus, by applying the specifications of the hydraulic motor of the rotation mechanism 52 of the drilling machine 1, the specifications of the transmission member, and the properties of the rock mass to be crushed to Equation (1), Equation (2), Equation (3), and Equation (4), it is possible to derive "the rotational pressure is within a predetermined range", which is the main configuration of the second invention of the present invention. And it is possible to derive the range of the feed pressure at the first rod from this range of the rotational pressure. Fig. 14 shows the relationship between the rotational pressure Pr and the feed pressure FP.

[0100] (Change in the feed pressure subtraction amount according to the drilling direction) As described above, the embodiments of the present invention have been described on the premise that the drilling direction is downward, but among the loads acting on the bit 8, the load due to the total mass of the transmission member, the rock drilling machine body 5, and the carriage (hereinafter, the bit load WB) varies depending on the drilling direction. WB = W0 × sin θ ··· Equation (5) W0: Total mass of the transmission member, rock drilling machine, and carriage θ: Angle formed by the drilling axis and the horizontal plane (i.e., the inclination angle)

[0101] The change amount ΔWB of the bit load due to adding one rod is as follows according to Equation (5). WB + ΔWB = (W0 + WR) × sin θ ∴ ΔWB = WR × sin θ ··· Equation (6) WR: Mass per rod And the change amount of the rotational torque generated between the bit 8 and the rock mass R is proportional to the change amount ΔWB of the bit load, and since the feed pressure FP is proportional to the rotational torque, the feed pressure subtraction amount ΔFP is proportional to the change amount ΔWB of the bit load. ΔFP = γ × ΔWB ··· Equation (7) γ: Coefficient, which is appropriately set according to the state of the rock mass R and the transmission member

[0102] Therefore, according to equations (6) and (7), the relationship between the drilling direction and the feed pressure reduction amount ΔFP can be expressed as equation (8). ΔFP = γ × WR × sinθ ··· Equation (8) According to equation (8), when focusing on the drilling direction of the drilling machine, the feed pressure reduction amount ΔFP is maximum when the drilling direction is directly downward (= plunge angle 90°) and minimum when it is horizontal (= plunge angle 0°), while when it is upward (= negative plunge angle), the feed pressure will be added.

[0103] (Comparison between the present invention and RF control) Finally, regarding the differences between the so-called RF control, which controls the feed pressure in real time with the rotary pressure as a parameter and is adopted for the purpose of optimizing the drilling state in this type of drilling machine, and the present invention will be mentioned.

[0104] The rotary pressure changes due to the rock penetration state between the bit 8 and the rock mass R and the rotary torque generated when the bit 8 and the MF rod 7 come into contact with the hole wall of the blast hole BH. That is, even if the rock penetration state is insufficient, if the contact resistance with the hole wall is large, the rotary torque may increase. When RF control is performed in such a state, the rock penetration state will further deteriorate, and a so-called "dry firing state" will occur where the bit 8 strikes without penetrating the rock mass R.

[0105] The dry firing state damages the transmission members such as the bit 8 and the MF rod 7 and the rock drilling machine main body 5, but in the high-power impact mechanism 50 targeted by the present invention, the damage will be severe. Therefore, RF control is not suitable for the drilling machine 1 equipped with the high-power impact mechanism 50.

[0106] And the problem of the present invention is to prevent the hole bending of the MF rod 7 and the excessive tightening of the threaded portion. The applicant of the present application has arrived at the present invention of adjusting the feed pressure according to the number of the attached MF rods 7. In addition, although the rotational pressure is referred to when subtracting the feed pressure in the "Second Invention" as well, the technical ideas of the present invention and RF control are fundamentally different from each other in terms of the purpose, configuration, and effects.

[0107] As described above, the embodiments of the present invention have been described with reference to the drawings. However, the control device for a drilling machine according to the present invention and the drilling machine equipped with the same are not limited to the above-described embodiments, and various other modifications and changes to each component are of course allowed without departing from the gist of the present invention. It is also possible to appropriately combine the configurations of the above-described embodiments.

Explanation of Reference Numerals

[0108] 1... Drilling machine, 2... Traveling bogie, 3... Boom, 4... Guide shell, 5, 5´... Rock drill, 5a, 5a´... Front stage portion, 5b... Central stage portion, 5b´... Reference position, 5c, 5c´... Rear stage portion, 5d, 5d´ High-pressure circuit, 5e, 5e´... Drain circuit, 6... Feed mechanism, 7... MF rod, 7m... Male screw portion, 7m1... Male screw, 7m2... Shoulder surface, 7f... Female screw portion, 7f1... Female screw, 7f2... Rear end surface, 7h... Water hole, 8... Bit, 9... Rod changer, 10... Rod magazine, 20... Control device, 50... Impact mechanism, 51... Impact piston, 52... Rotation mechanism, 53... Shank rod, 54... Dual damper mechanism, 55... Pushing piston, 56... Damping piston, 57... Chuck driver bush, 60... Single floating damper mechanism, 61... Floating piston, 62... Damper oil chamber, 63... Low-pressure port, 64... High-pressure port, FP... Feed pressure, FPup... Upper limit feed pressure, FPlo... Lower limit feed pressure, FPcr... Critical feed pressure, ΔFP... Feed pressure subtraction amount, ST1, ST1´... Forward stroke, ST2, ST2´... Reverse stroke, SL(H)... High-pressure side seal length, SL(L)... Low-pressure side seal length, P... Pump, T... Tank, R... Rock formation, BH... Blasting hole, WB... Bit load,

Claims

1. A drilling machine that performs long-hole drilling while attaching a rod in the direction of the drilling axis, comprising: a striking mechanism disposed on the rear end side of the rod to strike the rear end of the rod; a rotating mechanism that rotates the rod around the drilling axis; and a damper mechanism having a pushing action that presses a bit fixed to the tip of the rod against an object to be crushed, and a rock drilling machine main body provided with the damper mechanism, and a feed mechanism that feeds the rock drilling machine main body along the drilling axis. In the control device that controls the feed pressure of the feed mechanism, A control device for a drilling machine, characterized in that the feed pressure is subtracted according to the number of rods attached.

2. The control device for a drilling machine according to claim 1, wherein the subtraction amount of the feed pressure is adjusted so that the rotation pressure of the rotation mechanism is maintained within a predetermined range.

3. The control device for a drilling machine according to claim 1, wherein the subtraction amount of the feed pressure is adjusted between an upper limit feed pressure at which the threaded portion at the attachment location of the rod is overtightened and a lower limit feed pressure at which the pushing action of the damper mechanism stops functioning, with respect to the subtracted feed pressure.

4. The control device for a drilling machine according to any one of claims 1 to 3, wherein the subtraction amount of the feed pressure is adjusted so that the subtracted feed pressure exceeds a critical feed pressure at which the piston reaction force associated with the strike and the feed thrust balance each other.

5. The damper mechanism advances upon receiving supply of a damper pressure from the outside and applies a pressing force to the rod, The control device for a drilling machine according to any one of claims 1 to 3, characterized in that when the subtracted feed pressure is lower than a critical feed pressure at which the piston reaction force associated with the strike and the feed thrust balance each other, the damper pressure is added.

6. The control device for a drilling machine according to claim 5, wherein the addition amount of the damper pressure is adjusted so that the damper mechanism is in a position retracted from its forward stroke end throughout the strike cycles.

7. The control device includes mode selection means for selecting drilling conditions, The control device for a drilling machine according to claim 3, characterized in that the mode selection means can select a speed priority mode for adjusting the feed pressure based on the upper limit feed pressure.

8. The control device includes mode selection means for selecting drilling conditions, The mode selection means can select a hole bending prevention mode for adjusting the feed pressure based on the lower limit feed pressure. The control device for a drilling machine according to claim 3, characterized in that.

9. The control device includes mode selection means for selecting drilling conditions, The mode selection means, In a region where the upper limit feed pressure at which the screw portion at the joint of the rod is overtightened is higher than the critical feed pressure, the feed pressure is adjusted based on the critical feed pressure, The control device for a drilling machine according to claim 4, characterized in that a hybrid mode for adjusting the feed pressure based on the upper limit feed pressure can be selected in a region where the upper limit feed pressure is lower than the critical feed pressure.

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