JP2020007727A - Hydraulic rock drill, damper hydraulic circuit and method for controlling pressure of damper - Google Patents

Abstract

To provide a dumper hydraulic circuit for making it possible to control a damper pressure with a simple configuration by using only a hydraulic device that is relatively easily available without performing electro-hydraulic conversion, and to facilitate adjustment and maintenance for efficiently driving a hydraulic rock drill.SOLUTION: A damper hydraulic circuit YK4 that is used in a hydraulic rock drill has: a damper input port DN1 connected to a hydraulic power source P4; a damper output port PD1 for outputting a hydraulic pressure to the damper mechanism PK; a flow control valve 54 provided between the damper input port and the damper output port; a direct acting relief valve 52 with an input port connected to an output port side of the flow control valve; a pilot operated relief valve 53 with an input port connected to an output port side of a direct acting relief valve and an output port connected to a return port connected to the tank; and a pilot line LP1 that connects the hydraulic pressure supplied to the feed mechanism FK to be supplied to the pilot port of the pilot operated relief valve.SELECTED DRAWING: Figure 5

Description

  The present invention relates to a hydraulic rock drill, a damper hydraulic circuit therefor, and a pressure control method for the damper.

  2. Description of the Related Art Conventionally, hydraulic rock drills are often used for crushing or drilling of rock or the like. Hydraulic rock drills of various structures and types have been proposed.

  Patent Literature 1 discloses a hydraulic rock drill provided with a hydraulic hitting device, a rotating device, and a feed device. The drill rod is connected to the shank rod attached to the tip of the main body, and the shank rod is hit with a piston provided in the cylinder cavity, and the hole is drilled with the lock bit attached to the tip of the drill rod. During drilling, a drilling rod is rotated by a rotating device provided on the main body, and a drill having a predetermined depth is drilled while the drilling machine is advanced by a feed device. Since the target rock is not homogeneous, the operator of the rock drill adjusts the magnitude, strength, thrust, and the like of the impact and rotation while observing the rock quality, the state of the rock, and the like.

  Patent Literature 2 discloses a hydraulic rock drill in which energy generated by striking a shank rod with a piston is transmitted to the bit via the rod, and the bit hits and breaks the rock.

  According to this hydraulic rock drill, the reflected energy from the rock when the rock is hit is transmitted from the bit to the rock rock body via the rod and the shank rod, and the rock rock body is once retreated by the reflected energy. The rock drill body advances by the crushing length of one impact by the thrust of the feeder, and performs the next impact there. By repeating this process, drilling work is performed.

  The hydraulic rock drill is provided with a hydraulic damper (buffer mechanism) in order to buffer the reflected energy and improve the impact transmission efficiency.

  In Patent Literature 2, a pressure control unit using an electromagnetic proportional control valve is provided for adjusting the pressure of the hydraulic pressure supplied to the damper (damper pressure). The pressure control means detects a feed pressure for sending the rock drill body forward, and performs arithmetic processing based on an electrical detection signal from the pressure sensor so that the damper pressure has a predetermined relationship with the feed pressure. An arithmetic processing unit, an electromagnetic proportional control valve that controls the oil pressure to the pressure reducing valve based on an electric signal from the arithmetic processing unit, a pressure reducing valve that reduces the pump pressure to a damper pressure based on the oil pressure from the electromagnetic proportional control valve, and the like. ing.

Japanese Patent Application Laid-Open No. 11-173063 JP 2001-341083 A

  In the above-described hydraulic rock drill, the rock drilling efficiency greatly changes depending on the degree of the damping action of the damper, and therefore it is necessary to adjust the damper pressure well.

  According to the pressure control means proposed in Patent Document 2, an electric detection signal of the feed pressure detected by the pressure sensor is sent to the arithmetic processing unit. The arithmetic processing device performs a pressure calculation based on the electrical detection signal so that the damper pressure has a predetermined relationship with the feed pressure, and sends an electrical signal as a result of the calculation to the electromagnetic proportional control valve. The electromagnetic proportional control valve controls the oil pressure to the pressure reducing valve based on the electric signal from the arithmetic processing device, and the pressure reducing valve changes the pump pressure to a damper pressure having a predetermined relationship based on the oil pressure from the electromagnetic proportional control valve. Reduce pressure. In this way, the damper pressure is controlled.

  However, in a conventional device such as cited document 2, the pressure sensor once converts the oil pressure into an electric signal to perform arithmetic processing, and based on the arithmetic result, performs electro-hydraulic conversion using an electromagnetic proportional control valve to perform damper pressure. , The configuration is complicated, adjustment and maintenance are not easy, and a technician who has both hydraulic technology and electric technology must be employed. In particular, the electromagnetic proportional control valve has a delicate operation, is vulnerable to impact, and has a relatively high probability of occurrence of a failure.

  The present invention provides a simple configuration using only hydraulic equipment that is relatively easily available without performing electro-hydraulic conversion, controls damper pressure, and performs adjustment and maintenance for efficiently operating a hydraulic rock drill. The purpose is to make it easier.

  An apparatus according to the present invention includes a propulsion mechanism that presses and propels a rotating tool toward a target by hydraulic pressure, a striking mechanism that strikes the tool toward the target, and a striking mechanism that strikes the tool from the target. In a hydraulic rock drill having a damper mechanism for buffering the shock due to reflection of the oil pressure and a damper hydraulic circuit for supplying oil pressure to the damper mechanism, the damper hydraulic circuit has a damper input port connected to a hydraulic source, A damper output port for outputting oil pressure to the damper mechanism, a flow control valve provided between the damper input port and the damper output port, and an input port connected to an output port of the flow control valve. An input port is connected to a direct-acting relief valve and an output port of the direct-acting relief valve, and an output port is connected to a return port connected to the tank. Been, it has a pilot-operated relief valve, and a pilot line for connecting to the hydraulic pressure is supplied to be supplied to the propulsion mechanism to the pilot port of the pilot-operated relief valve.

  A damper hydraulic circuit according to the present invention includes a propulsion mechanism that pushes and rotates a rotating tool toward an object by hydraulic pressure, a striking mechanism that strikes the tool toward the object, and a method that strikes the object by striking the tool. A damper hydraulic circuit for supplying hydraulic pressure to the damper mechanism, the damper hydraulic circuit being used in a hydraulic rock drill having a damper mechanism that buffers a shock due to reflection from an object, the damper input port being connected to a hydraulic pressure source A damper output port for outputting oil pressure to the damper mechanism, a flow regulating valve provided between the damper input port and the damper output port, and an input port connected to the output port side of the flow regulating valve. The input port is connected to the output port side of the direct acting relief valve, and the output port is connected to the return port side connected to the tank. A connection has been, a pilot-operated relief valve, and a pilot line for connecting to the hydraulic pressure is supplied to be supplied to the propulsion mechanism to the pilot port of the pilot-operated relief valve.

  Advantageous Effects of Invention According to the present invention, it is possible to control a damper pressure with a simple configuration using only hydraulic equipment that is relatively easily available without performing electro-hydraulic conversion, and to operate a hydraulic rock drill efficiently. Adjustment and maintenance are facilitated.

It is a figure showing the schematic structure of the hydraulic drilling machine concerning the present invention. It is sectional drawing which shows the rough structure of the drill head of the hydraulic rock drill of FIG. FIG. 3 is an enlarged sectional view showing a damper mechanism of the drill head of FIG. 2. FIG. 3 is an enlarged sectional view showing a damper mechanism of the drill head of FIG. 2. It is a figure which shows the hydraulic circuit of a hydraulic rock drill. It is a figure showing other examples of a feed hydraulic circuit. It is a figure showing an example of the relation between feed pressure Pp, differential pressure Pα, and damper pressure. It is sectional drawing which shows the example of a structure of the pilot operated relief valve used for a damper hydraulic circuit. It is sectional drawing which shows the example of a structure of the direct-acting relief valve used for a damper hydraulic circuit. FIG. 7 is a diagram illustrating an example of a device configuration of a feed hydraulic circuit illustrated in FIG. FIG. 7 is a diagram illustrating an example of a device configuration of a feed hydraulic circuit illustrated in FIG.

  The hydraulic rock drill 1 according to the present embodiment includes a propulsion mechanism that pushes a rotating tool toward an object by hydraulic pressure to propel the tool, a striking mechanism that strikes the tool toward the object, and an object that is struck by the tool. It has a damper mechanism that buffers the impact due to the reflection from the oil pressure, and a damper hydraulic circuit that supplies oil pressure to the damper mechanism. The details will be described below.

  FIG. 1 shows a schematic configuration of a hydraulic rock drill 1 according to the present invention, and FIG. 2 shows a schematic structure of a drill head 16 of the hydraulic rock drill 1 of FIG.

  In FIG. 1, a hydraulic rock drill 1 includes a frame 11, sprockets 12a and 12b rotatably attached to both ends of the frame 11, a chain 13 spanned over the sprockets 12a and 12b, and a feed for rotationally driving the sprocket 12a. A hydraulic motor 14, a carriage 15 connected to the chain 13 and linearly moving along the frame 11, a drill head 16 attached to the carriage 15, and the like. These are examples of the configuration of a feed mechanism (propulsion mechanism) FK that propels the drill head 16.

  A drill rod (shank rod) 18 extends from the tip of the drill head 16. The drill rod 18 is rotatably and slidably supported at its distal end by a centrizer 19 provided on the frame 11. The drill rod 18 is driven to rotate by a hydraulic motor provided in the drill head 16, and is hit by a hitting mechanism built in the drill head 16, moves with the movement of the drill head 16, and moves at the tip of the drill rod 18. The object, such as a bedrock, is crushed and pierced by a bit 20 as a tool provided in the apparatus.

  FIG. 2 shows a schematic structure of the drill head 16 of the hydraulic rock drill 1 of FIG. 1, and FIGS. 3 and 4 show an enlarged view of a damper mechanism PK of the drill head 16 of FIG. . In FIG. 3, the damper piston 33 is located at the forward end, and in FIG. 4, the damper piston 33 is at the intermediate position.

  In FIG. 2, the drill head 16 includes a striking mechanism DK including a housing 31, a striking piston 32, a damper mechanism PK including a damper piston 33, a bushing 34, a gear 35, a gear 36, a spline 37, a hydraulic motor 17, and the like. It has a rotation drive mechanism KK.

  A shank rod 18a protrudes from the front end side of the housing 31 so as to be slidable in the axial direction. The shank rod 18a is connected to the drill rod 18 and transmits a striking force and a rotating force. The shank rod 18a is rotated by the rotation driving hydraulic motor 17 via the gears 35 and 36 and the spline 37 in the rotation driving mechanism KK. Driven. The spline 37 and the shank rod 18a are connected in a rotational direction via a key, rotate integrally, and slide the shank rod 18a a predetermined distance (for example, about 25 mm) in the axial direction. Is possible.

  The striking piston 32 has a piston portion 321 at a central portion and rod portions 322 and 323 on both sides thereof, and can slide in a piston chamber 311 provided in the housing 31 in an axial direction. Although not shown, a known striking mechanism DK for striking the shank rod 18a around the striking piston 32 by periodically driving the striking piston 32 back and forth in the forward and backward directions, that is, the arrow M1 direction. Is provided. As an example of the impact mechanism DK, there is a hydraulic mechanism described in JP-A-11-173630. A damper mechanism PK configured around a damper piston 33 is provided at a boundary between the striking piston 32 and the shank rod 18a.

  In the hydraulic drilling machine 1, the drill head 16 reciprocates via the carriage 15 by running of the chain 13 by rotation of the hydraulic motor 14 of the feed mechanism FK. When the drill head 16 moves forward or is fed for drilling, the drill rod 18 advances while rotating, and at this time, a forward-facing impact is applied by the impact mechanism DK. Thereby, rocks and the like are crushed by the bit 20.

  3 and 4, the damper piston 33 has a large-diameter portion 331 sliding in the large-diameter chamber 42 provided in the housing 31, a land portion 332 sliding in the medium-diameter chamber 43, and a small-diameter chamber 44. It has a small diameter portion 333 that slides.

  The housing 31 has a hole 46 communicating with the medium diameter chamber 43, a hole 47 communicating with the large diameter chamber 42, and a hole 48 communicating with the large diameter chamber 42. The holes 46 and 47 are supplied with hydraulic pressure from a damper output port PD1 of a damper hydraulic circuit YK4 described later, and the hole 48 is connected to the tank T. That is, the hole 48 is a drain port.

  The chambers 42 and 44 are connected to the tank T via a drain passage.

  Note that a balance piston valve V11 may be inserted between the damper output port PD1 and the hole 46 as shown in the figure. The balance piston type valve V11 shown in the drawing has the same function as a check valve which is free flowing in the direction from the damper output port PD1 toward the hole 46, but has different effective areas at both ends of the spool for switching between open and closed. Therefore, when the pressure in the medium diameter chamber 43 communicating with the hole 46 decreases, the balance piston type valve V11 opens.

  When hydraulic pressure is supplied from the damper output port PD1, the damper piston 33 is pushed leftward in the figure by the pressure of the hydraulic pressure in the large diameter chamber 42 and the medium diameter chamber 43, and this pressing force is applied via the bushing 34 to the shank rod. 18a (that is, the drill rod 18) acts as a force for pushing forward.

  When the damper piston 33 is in a no-load state, that is, when the damper piston 33 is at the forward end as shown in FIG. 3, the hydraulic pressure acts only on the middle diameter chamber (first hydraulic chamber) 43. At this time, since the large-diameter chamber (second hydraulic chamber) 42 is connected to the tank T via the hole 48, the pressure is reduced and the pressure is almost zero, and the shank rod 18a is pushed forward. The force is a force proportional to the pressure acting on the medium diameter chamber (first hydraulic chamber) 43.

  When the drill head 16 is fed, the shank rod 18a retracts with respect to the housing 31 accordingly. Thus, the shank rod 18a pushes the damper piston 33 via the bushing 34, and the damper piston 33 retreats. When the damper piston 33 retreats, the hole 48 is closed and closed by the large-diameter portion 331, and the medium-diameter chamber 43 is closed and the pressure rises and the pressure increases. When the pressure in the middle diameter chamber 43 is increased, the balance piston type valve V11 is switched to the closed state. At this time, the force for pushing the shank rod 18a forward is the sum of the forces due to the pressures acting on the middle diameter chamber (first hydraulic chamber) 43 and the large diameter chamber (second hydraulic chamber) 42. .

  Note that when the medium diameter chamber 43 is closed, the pressure decreases due to leakage, but when the pressure decreases to a predetermined pressure, the balance piston type valve V11 switches to the open state, and hydraulic pressure is supplied to the medium diameter chamber 43. You.

  FIG. 5 shows a hydraulic circuit YK of the hydraulic rock drill 1.

  In FIG. 5, a hydraulic circuit YK includes a feed hydraulic circuit YK1 for a feed mechanism FK, a rotary hydraulic circuit YK2 for a rotary drive mechanism KK, a strike hydraulic circuit YK3 for a strike mechanism DK, and a damper mechanism PK. It has a damper hydraulic circuit YK4.

  Each of the hydraulic circuits YK1 to YK4 is supplied with a hydraulic pressure source having a predetermined pressure P1 to P4. These hydraulic pressure sources may be described as “hydraulic power source P1”, “hydraulic power source P2”, and the like. These hydraulic pressure sources P1 to P4 may be provided independently of each other, but may be shared as described later.

  The feed hydraulic circuit YK1 has a switching valve V1 and a relief valve 61. When the switching valve V1, which is a control valve, is switched by a control circuit (not shown), the feed hydraulic motor 14 rotates forward, reverse, or stops, and the drill head 16 moves forward, backward, or stops. When hydraulic pressure is supplied to the forward port (propulsion port) PF1, the vehicle moves forward, and when hydraulic pressure is supplied to the reverse port PF2, it reverses. The pressure Pp of the forward port PF1 is adjusted by the relief valve 61. The pressure Pp of the forward port PF1 may be described as “feed pressure Pp”.

  The adjustment of the pressure Pp by the relief valve 61 can be easily performed by a hydraulic engineer or a person in the field by manually turning a handle or an adjustment screw of the relief valve 61. To check the pressure, an appropriate pressure gauge may be attached.

  The feed hydraulic circuit YK1 is an example of the “pressure adjusting device” in the present invention. The forward port PF <b> 1 is an example of the “propulsion port” of the present invention, and is a port of the hydraulic motor 14 on the side where the action of pushing the tool toward the object by rotation of the hydraulic motor 14 occurs.

  The rotary hydraulic circuit YK2 has a switching valve V2 that is a control valve. The switching of the switching valve V2 causes the hydraulic motor 17 for rotational drive to rotate forward, reverse, or stop, and the shank rod 18a to rotate forward, reverse, or stop.

  The impact hydraulic circuit YK3 has a switching valve V3 that is a control valve. By switching the switching valve V3, the hydraulic pressure is supplied to the impact mechanism DK or stopped. When the hydraulic pressure is supplied, the striking mechanism DK operates to periodically apply a striking force to the shank rod 18a.

  The damper hydraulic circuit YK4 includes a damper input port DN1 connected to a hydraulic power source P4 via a switching valve V4 as a control valve, a damper output port PD1 for outputting oil pressure to a damper mechanism PK, a damper input port DN1, and a damper output. A flow control valve 51 provided between the port PD1; a direct acting relief valve 52 having an input port 52P1 connected to an output port 51P2 of the flow regulating valve 51; and an output port of the direct acting relief valve 52 The feed port 53P1 is connected to the side of 52P2, and the output port 53P2 is connected to the side of the return port connected to the tank T. The pilot operated relief valve 53 and the pilot port 53P3 of the pilot operated relief valve 53 are fed. Connected so that the hydraulic pressure supplied to the forward port PF1 of the hydraulic motor 14 is supplied. Has a Tsu door line LP1, the.

  Note that the pressure (Pr + Pα) of the damper output port PD1 may be described as “damper pressure”.

  The flow rate adjusting valve 51 adjusts the flow rate Q1 of the hydraulic pressure flowing therethrough. In the present embodiment, a flow rate compensating valve is used. In addition, a check valve 54 that allows free flow from the damper output port PD1 to the damper input port DN1 may be provided in parallel with the flow control valve 51.

  The direct acting relief valve 52 generates a differential pressure (set pressure) Pα between its input port 52P1 and output port 52P2. The magnitude of the differential pressure Pα is, for example, about 2 to 4 MPa, preferably about 2.5 to 3.5 MPa, and the center value is, for example, about 3 MPa, and can be adjusted manually.

  The pilot operated relief valve 53 generates a pressure Pr corresponding to the pressure Pp applied to the pilot port 53P3 at the input port 53P1. The pilot port 53P3 is connected to the forward port PF1 of the hydraulic motor 14 via the pilot line LP1, so that the pressure of the forward port PF1 is applied to the pilot port 53P3 as the pressure Pp.

  As a result, a pressure Pr that is substantially the same as the pressure Pp of the forward port PF1 is generated at the input port 53P1 of the pilot operated relief valve 53.

  At the input port 52P1 of the direct acting relief valve 52, a pressure (Pr + Pa) obtained by adding the differential pressure Pa to the pressure Pr of the input port 53P1 of the pilot operated relief valve 53 is output to the damper output port PD1. It is supplied to the damper mechanism PK.

  Note that the damper hydraulic circuit YK4 can be configured as one hydraulic circuit unit by attaching necessary hydraulic equipment to an appropriate housing or board and performing piping. Alternatively, these devices may be attached adjacent to the tank provided in the hydraulic pressure source P4. Alternatively, those devices may be arranged near the drill head 16.

  FIGS. 6A and 6B show another example of the feed hydraulic circuit YK1.

  In FIG. 6A, the feed hydraulic circuit YK1B has a pilot operated balancing valve 62 and a sequence valve 63 instead of the relief valve 61.

  The pilot-operated balancing valve 62 is inserted into a pipeline from the hydraulic pressure source P1 to a forward port (propulsion port) PF1. The sequence valve 63 has an input port connected to the pilot port of the pilot operated balancing valve 62, an output port connected to the tank side, and a pilot port connected to the forward port (propulsion port) of the hydraulic motor 14. It is connected to a backward port PF2 which is a port on the opposite side from PF1.

  When a pressure is generated in the forward port PF1 and the hydraulic motor 14 rotates forward and the drill head 16 advances, the pressure P1 is reduced by the pilot-operated balancing valve 62, and the pressure in the forward port PF1 is adjusted. Adjustment of the pressure by the pilot operated balancing valve 62 is performed by adjusting the set pressure of the sequence valve 63 connected to the pilot port.

  In this way, even when the pressure P1 is large, the pressure can be reduced to the pressure Pp required for driving the hydraulic motor 14 by the pilot-operated balancing valve 62.

  When pressure is generated in the retreat port PF2 and the hydraulic motor 14 rotates in the reverse direction and the drill head 16 retreats, the pressure of the input port of the sequence valve 63 decreases to near zero, thereby causing the pilot-operated balancing valve 62 to rotate. The pressure between the input and output ports drops to near zero (depressurized). Thereby, the return oil from the forward port PF1 flows into the tank T.

  In the feed hydraulic circuit YK1B, the pressure on the output side (output port) of the pilot operated balancing valve 62 (that is, the pressure of the forward port PF1) is provided without the sequence valve 63 provided. ) The pressure may be reduced by the pressure of the retreat port PF2, which is the port on the opposite side to PF1.

  For example, a pilot check valve is connected in place of the sequence valve 63, and the pilot check valve is opened by the pressure of the retreat port PF2, and the pressure between the input port and the output port of the pilot operated balancing valve 62 decreases to around zero. You may make it. Further, a pilot check valve may be connected between the forward port PF1 and the tank T, and the pilot check valve may be opened by the pressure of the backward port PF2 so that the pressure of the forward port PF1 decreases to around zero.

  In FIG. 6B, the feed hydraulic circuit YK1C has a pilot operated pressure reducing valve 64 and a check valve 65 instead of the relief valve 61.

  The pilot-operated pressure reducing valve 64 is inserted into a pipeline from the hydraulic pressure source P1 to a forward port (propulsion port) PF1. The check valve 65 is connected in parallel with the pilot-operated pressure reducing valve 64 so as to be free-flowing from the forward port PF1 toward the hydraulic power source P1.

  When pressure is generated in the forward port PF1 and the hydraulic motor 14 rotates forward and the drill head 16 moves forward, the pressure P1 is reduced by the pilot-operated pressure reducing valve 64, and the pressure in the forward port PF1 is adjusted. That is, even when the pressure P1 is large, the pressure can be reduced to the pressure Pp required for driving the hydraulic motor 14 by the pilot-operated pressure reducing valve 64.

  When pressure is generated in the retreat port PF2 and the hydraulic motor 14 rotates reversely and the drill head 16 retreats, the return oil from the forward port PF1 flows into the tank T via the check valve 65.

  In the case where the feed hydraulic circuits YK1B and C are used, the pressure Pp is adjusted by manually turning an adjusting screw or a handle of the sequence valve 63 or the pilot operated pressure reducing valve 64 by a hydraulic engineer or a person in the field. It can be done easily.

  When the feed hydraulic circuits YK1B and YK1C are used, the hydraulic source P1 of the feed mechanism FK and the hydraulic source P4 of the damper mechanism PK can be shared by a single common hydraulic source. That is, a single hydraulic pump is used to generate hydraulic pressure, which can be commonly used as the hydraulic pressure sources P1 and P4.

  Next, an example of setting a pressure in the hydraulic circuit YK shown in FIG. 5 will be described.

  The pressure (feed pressure) Pp of the forward port PF1 of the hydraulic motor 14 in the feed mechanism FK is set to, for example, 5 MPa. At this time, the pressure (differential pressure) Pα of the direct acting relief valve 52 in the damper mechanism PK is set at 2.2 to 3.0 MPa, and the pressure at the damper output port PD1, that is, the damper pressure (Pr + Pα) is 7.2 to 2.0. Set to 8.0 MPa.

  In this case, the flow rate Q1 in the flow control valve 51 is set to, for example, 10 to 13 L / min.

  Further, the pressure (feed pressure) Pp of the forward port PF1 is set to, for example, 8 MPa. At this time, the pressure (differential pressure) Pα of the direct acting relief valve 52 is set to 2.2 to 3.0 MPa, and the damper pressure (Pr + Pα) is set to 10.2 to 11.0 MPa.

  FIG. 7A shows the relationship between the change in the feed pressure Pp and the change in the differential pressure Pα and the flow rate Q1. FIG. 7B shows the relationship between the change in the feed pressure Pp and the damper pressure (Pr + Pα). Are shown, respectively.

  FIG. 7A shows changes in the differential pressure Pα and the flow rate Q1 when the feed pressure Pp is changed by setting the feed pressure Pp to 5 MPa, the differential pressure Pα to 3 MPa, and the flow rate Q1 to 12 L / min. Is observed.

  As shown in FIG. 7A, when the feed pressure Pp is in the range of 2 to 8 MPa, the differential pressure Pα is in the range of 3.4 to 2.8 MPa, and the flow rate Q1 is in the range of 15 to 7.5 L / min. is there. Therefore, the damper pressure (Pr + Pα) supplied to the damper mechanism PK is always higher than the feed pressure Pp by the differential pressure Pα of 3.4 to 2.8 MPa.

  FIG. 7B shows the basic relationship between the change in the feed pressure Pp and the damper pressure (Pr + Pα).

  As shown in FIG. 7B, when the feed pressure Pp is in a predetermined range, the damper pressure (Pr + Pα) increases almost in proportion to the increase in the feed pressure Pp. As shown in FIG. 7A, the differential pressure Pα is not strictly constant, but its fluctuation is within a small predetermined range, and it can be said that the damper pressure (Pr + Pα) is almost proportional to the feed pressure Pp.

  More specifically, the differential pressure Pα tends to decrease slightly as the feed pressure Pp increases. Therefore, as shown by the two-dot chain line in FIG. 7B and the solid line in the curve, the inclination of the increase in the damper pressure (Pr + Pα) tends to slightly decrease with the increase in the feed pressure Pp. is there.

  This is caused by the characteristic of the relief valve because the pressure difference between the damper pressure (Pr + Pα) and the hydraulic pressure source decreases as the feed pressure Pp increases, and the flow rate Q1 decreases. These problems can be prevented by making the flow regulating valve a pressure compensation type.

  In the hydraulic rock drill 1, the damper pressure (Pr + Pα) may not always be exactly proportional to the feed pressure Pp, and may be used depending on the actual structure of the hydraulic rock drill 1 and the drill head 16. It is possible to make adjustments so as to obtain an optimum operation by selecting a device to be operated.

  As described above, by using the damper hydraulic circuit YK4, the damper pressure can always be set to a value that is always larger than the feed pressure Pp by the differential pressure Pα. The damper hydraulic circuit YK4 is composed of a flow control valve 51, a direct acting relief valve 52, and a pilot operated relief valve 53, and uses only hydraulic equipment that is relatively easily available without performing electric-hydraulic conversion. The damper pressure can be controlled with a simple configuration, and adjustment and maintenance for efficiently operating the hydraulic rock drill 1 can be facilitated.

  By controlling the damper pressure, the movement of the shank rod 18a, that is, the drill rod 18, which tends to return by receiving a repulsive force from rock or the like at the time of impact can be effectively suppressed by the damper mechanism PK. Thereby, the rocking property of the bit 20 is ensured, and the energy of the shock wave can be reliably transmitted to the bedrock.

  Next, specific examples of devices used for the hydraulic circuit YK will be described.

  FIG. 8 is a sectional view showing an example of the structure of the pilot operated relief valve 53 used in the damper hydraulic circuit YK4.

  In FIG. 8, a pilot-operated relief valve 53 is provided with a piston 72 for adjusting a main flow rate and a pilot valve 75 for pressure adjustment inside a body 71.

  The pressure oil entering from the input port 53P1 acts on the lower surface of the piston 72, and at the same time, enters the spring chamber 74a through the orifice 73a, and further acts on the needle valve 75 through the passages 73b and 73c. When the pressure acting on the needle valve 75 exceeds the set value of the spring 76, the needle valve 75 opens and the pressure oil in the spring chamber 74a flows out to the needle chamber 74b. When the pressure in the spring chamber 74a decreases due to this operation, the piston 72 rises, and the flow path from the input port 53P1 to the output port 53P2 opens.

  In this case, the set value of the spring 76 can be arbitrarily adjusted by rotating the adjustment screw 77.

  The pressure oil that has flowed out to the needle chamber 74b can flow out to the output port 53P2 via the passage 73d.

  In the present embodiment, a pilot pipeline LP1 is connected to the pilot port (vent port) 53P3. Therefore, when pressure Pp is applied to pilot port 53P3 via pilot line LP1, the pressure in spring chamber 74a becomes substantially equal to pressure Pp, and the pressure in input port 53P1 is kept substantially equal to pressure Pp. . That is, the pressure at the input port 53P1 is remotely controlled by the pressure Pp at the pilot port 53P3 via the pilot line LP1.

  FIG. 9 is a sectional view showing an example of the structure of the direct acting relief valve 52 used in the damper hydraulic circuit YK4.

  9, a direct acting relief valve 52 is provided with a poppet valve 82, a spring 83, an adjusting screw 84, and the like inside a body 81.

  The pressure oil entered from the input port 52P1 flows into the poppet chamber 85a and acts on the poppet valve 82. When the pressure acting on the poppet valve 82 exceeds the set value of the spring 83, the poppet valve 82 opens, and the pressure oil in the poppet chamber 85a flows into the spring chamber 85b and reaches the output port 52P2. When the pressure in the poppet chamber 85a decreases due to this operation, the poppet valve 82 is closed by the force of the spring 83. Thereby, the pressure of the input port 52P1 is maintained at the set pressure. The set pressure can be arbitrarily adjusted by rotating the adjustment screw 84 with a driver or the like.

  FIG. 10 shows an example of a device configuration of the feed hydraulic circuit YK1B.

  10, a pilot-operated balancing valve 62 is provided with a valve body 92, a spring 93, a needle valve 94, a spring 95, an adjustment handle 96, and the like inside a body 91.

  The pressure oil entering from the input port 62P1 flows into the valve chamber 97a and acts on the valve body 92. When the pressure acting on the valve element 92 exceeds the set value of the spring 93, the valve element 92 opens, the valve chamber 97a communicates with the drain port 62PD, and the pressure oil flows out to the tank T. When the pressure in the valve chamber 97a decreases due to this operation, the valve element 92 is closed by the pressure of the spring 93 and the pilot port 62P3.

  As a result, the pressure of the input port 62P1 is maintained at the set pressure, and the pressure Pp is output to the hydraulic motor 14 as the feed pressure of the forward port PF1 and the pilot operated relief valve 53 is controlled via the pilot line LP1. Output to pilot port 53P3.

  The pressure Pp set by the pilot-operated balancing valve 62 can be easily unloaded by setting the pressure of the sequence valve 63.

  FIG. 11 shows an example of a device configuration of the feed hydraulic circuit YK1C.

  11, a pilot-operated pressure reducing valve 64 is provided with a valve body 102, a spring 103, a needle valve 104, a spring 105, an adjustment handle 106, a check valve body 107, and the like inside a body 101.

  The pressure oil entering from the input port 64P1 reaches the output port 64P2, enters the spring chamber 108b via the passage 109a and the orifice 109b, and reaches the needle chamber 108c to act on the needle valve 104. When the pressure acting on the needle valve 104 exceeds the set value of the spring 105, the needle valve 104 opens, and the pressure oil flows out to the tank T via the drain hole 109c. Thus, the pressure in the spring chamber 108b becomes the set pressure set by the spring 105. The pressure of the output port 64P2 is maintained at a pressure corresponding to the set pressure set by the spring 105.

  The pressure Pp of the output port 64P2 is output to the hydraulic motor 14 as the feed pressure of the forward port PF1, and is also output to the pilot port 53P3 of the pilot operated relief valve 53 via the pilot line LP1.

  The set pressure of the spring 105, that is, the pressure Pp set by the pilot-operated pressure reducing valve 64, can be easily adjusted by the adjusting handle 106.

  These devices are easily available on the market, and those skilled in the art can easily assemble and use them as the hydraulic circuit YK.

  In the embodiment described above, the feed mechanism FK, the rotation drive mechanism KK, the impact mechanism DK, the damper mechanism PK, the feed hydraulic circuit YK1, the rotary hydraulic circuit YK2, the impact hydraulic circuit YK3, the damper hydraulic circuit YK4, the hydraulic circuit YK, and the drill The configuration, structure, arrangement, number, material, combination, dimensions, pressure value, and the like of the entire head 16 and the hydraulic rock drill 1 can be various other than those described above.

1 hydraulic rock drill 14 hydraulic motor 16 drill head 17 hydraulic motor 18 drill rod (tool)
18a Shank rod (tool)
20 bits (tool)
32 Striking piston 33 Damper piston 51 Flow control valve 52 Direct acting relief valve 53 Pilot operated relief valve LP1 Pilot line DN1 Damper input port PD1 Damper output port P4 Hydraulic power source V4 Switching valve Pα Differential pressure (set pressure)
Pp Feed pressure Pr pressure (feed pressure)
(Pr + Pα) Damper pressure (pressure)
FK feed mechanism (propulsion mechanism)
KK Rotating drive mechanism DK Striking mechanism PK Damper mechanism YK Hydraulic circuit YK1 Feed hydraulic circuit YK2 Rotating hydraulic circuit YK3 Striking hydraulic circuit YK4 Damper hydraulic circuit

Claims (10)

A propulsion mechanism that presses and propels the rotating tool toward the object by hydraulic pressure, a striking mechanism that strikes the tool toward the object, and a hydraulically impacted impact from the object by hitting the tool. In a hydraulic rock drill having a damper mechanism for buffering and a damper hydraulic circuit for supplying hydraulic pressure to the damper mechanism,
The damper hydraulic circuit includes:
A damper input port connected to a hydraulic source,
A damper output port for outputting hydraulic pressure to the damper mechanism;
A flow regulating valve provided between the damper input port and the damper output port,
A direct acting relief valve having an input port connected to the output port side of the flow regulating valve,
An input port is connected to an output port side of the direct acting relief valve, and an output port is connected to a return port side connected to the tank; a pilot operated relief valve;
A pilot pipe connecting the pilot port of the pilot operated relief valve to be supplied with hydraulic pressure supplied to the propulsion mechanism,
A hydraulic rock drill having the following features. The pressure Pr at the input port of the pilot operated relief valve corresponds to the pressure Pp of the hydraulic pressure supplied to the pilot port,
A pressure (Pr + Pα) obtained by adding a set pressure Pα of the direct acting relief valve to the pressure Pr is output to the damper output port.
The hydraulic rock drill according to claim 1. The flow control valve is a pressure compensation type flow control valve,
The hydraulic rock drill according to claim 1 or 2. The propulsion mechanism includes:
A hydraulic motor for propulsion,
A pressure adjusting device connected to a propulsion port that is a port of the hydraulic motor on a side where the action of pushing the tool toward the object is generated by rotation of the hydraulic motor,
Is provided,
One end of the pilot line is connected to the propulsion port side,
The hydraulic rock drill according to any one of claims 1 to 3. The hydraulic source of the propulsion mechanism and the hydraulic source of the damper hydraulic circuit are shared by a single single hydraulic source,
As the pressure adjusting device,
Has a pilot operated balancing valve,
The pilot-operated balancing valve is inserted into a pipeline from the hydraulic pressure source to the propulsion port,
The pressure on the output side of the pilot-operated balancing valve is configured to be depressurized by the pressure on the port of the hydraulic motor opposite to the propulsion port.
The hydraulic rock drill according to claim 4. The hydraulic source of the propulsion mechanism and the hydraulic source of the damper hydraulic circuit are shared by a single common hydraulic source,
As the pressure adjusting device,
It has a pilot operated pressure reducing valve and a check valve,
The pilot-operated pressure reducing valve is inserted into a pipeline from the hydraulic pressure source to the propulsion port,
The check valve is connected in parallel with the pilot-operated pressure-reducing valve and in a free flow from the propulsion port toward the hydraulic power source side.
The hydraulic rock drill according to claim 4. A propulsion mechanism that presses and propels the rotating tool toward the object by hydraulic pressure, a striking mechanism that strikes the tool toward the object, and a hydraulic pressure-induced impact from the object due to the impact on the tool. Used in a hydraulic rock drill having a damper mechanism to buffer, a damper hydraulic circuit for supplying hydraulic pressure to the damper mechanism,
A damper input port connected to a hydraulic source,
A damper output port for outputting hydraulic pressure to the damper mechanism;
A flow regulating valve provided between the damper input port and the damper output port,
A direct acting relief valve having an input port connected to the output port side of the flow regulating valve,
An input port is connected to an output port side of the direct acting relief valve, and an output port is connected to a return port side connected to a tank, a pilot operated relief valve,
A pilot pipe connecting the pilot port of the pilot operated relief valve to be supplied with hydraulic pressure supplied to the propulsion mechanism,
And a damper hydraulic circuit for a hydraulic rock drill. The pressure Pr at the input port of the pilot operated relief valve corresponds to the pressure Pp of the hydraulic pressure supplied to the pilot port,
A pressure (Pr + Pα) obtained by adding a set pressure Pα of the direct acting relief valve to the pressure Pr is output to the damper output port.
A damper hydraulic circuit for a hydraulic rock drill as claimed in claim 7. The flow control valve is a pressure compensation type flow control valve,
A damper hydraulic circuit for a hydraulic rock drill according to claim 7 or 8. A propulsion mechanism that presses and propels the rotating tool toward the object by hydraulic pressure, a striking mechanism that strikes the tool toward the object, and a hydraulically impacted impact from the object by hitting the tool. In a hydraulic rock drill having a damper mechanism for buffering, a method for controlling a pressure of hydraulic pressure supplied to the damper mechanism,
A damper input port connected to a hydraulic source,
A damper output port for outputting hydraulic pressure to the damper mechanism;
A flow regulating valve provided between the damper input port and the damper output port,
A direct acting relief valve having an input port connected to the output port side of the flow regulating valve,
An input port is connected to an output port side of the direct acting relief valve, and an output port is connected to a return port side connected to the tank; a pilot operated relief valve;
A pilot pipe connecting the pilot port of the pilot operated relief valve to be supplied with hydraulic pressure supplied to the propulsion mechanism,
Using a damper hydraulic circuit having
Making the pressure Pr of the input port of the pilot operated relief valve correspond to the pressure Pp of the hydraulic pressure supplied to the propulsion mechanism;
Outputting to the damper mechanism a hydraulic pressure of a pressure (Pr + Pα) obtained by adding the set pressure Pα of the direct acting relief valve to the pressure Pr;
A pressure control method for a damper in a hydraulic rock drill.

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