Hydraulic System with Safety Mode, Rock Drilling Equipment and Method

Abstract

Hydraulic system, rock drilling equipment and method for temporarily restricting the output performance of a hydraulic drilling actuator (Ha) during the execution of a safety functional feature of a hydraulic system (HS). The output performance is restricted by restricting the hydraulic fluid flow generated in the hydraulic circuit (CL, OL) of the hydraulic drilling actuator, thereby generating a fluid flow of a restricted magnitude at the hydraulic pump. In this way, a restricted operating mode (ROM) is enabled and controlled by a control unit (CU).

Description

Technical Field

[0001] The present invention relates to a hydraulic system for a rock drilling device. The hydraulic system is provided with a safety mode for enhancing safety.

[0002] The present invention further relates to a rock drilling device and a method for ensuring the safe operation of a hydraulic drilling actuator.

[0003] The field of the present invention is more specifically defined as follows. The hydraulic system includes: at least one hydraulic circuit provided with a hydraulic power unit, the hydraulic power unit including a hydraulic pump driven by a motor; at least one hydraulic drilling actuator powered by the hydraulic pressure and flow rate generated by the hydraulic power unit; wherein the hydraulic system is provided with safety functional features for restricting the characteristics of the hydraulic fluid inputted to the at least one hydraulic drilling actuator to temporarily restrict the output performance of the hydraulic drilling actuator; and the hydraulic system is provided with at least one control unit, the at least one control unit including at least one restricted operation mode, the at least one restricted operation mode serving as the safety functional feature and being configured to restrict the magnitude of the output flow rate of the hydraulic power unit, whereby the movement speed of the hydraulic drilling actuator is restricted due to the limited magnitude of the input flow rate received. Background Art

[0004] At mines and other work sites, different types of rock drilling devices are used to drill blast holes, reinforcement holes, and other types of holes by means of a rock drill mounted on the boom of the rock drilling device. The rock drill can be hydraulically operated and can be surrounded by a safety cage or a noise damper, or there can be other safety devices to prevent entry into the interior of the safety area of the rotating machine elements. However, sometimes it is necessary to open the safety device and manually assist the operation of the rock drilling work. For such a situation, the hydraulic system that powers the hydraulic actuators of the hydraulic rock drill needs to be provided with safety functional features for restricting the output performance of these hydraulic actuators to a safe level. Known safety features and solutions for enhancing the safety of hydraulic drilling actuators have shown some disadvantages. Summary of the Invention

[0005] The object of the present invention is to provide a novel and improved hydraulic system and a rock drilling device equipped with such a hydraulic system, and also to provide a novel and improved method for enhancing operation safety by temporarily restricting the output performance.

[0006] The hydraulic system according to the invention is characterized by the following features: the hydraulic pump is a fixed-displacement hydraulic pump driven by an electric motor; the electric motor is controlled by means of at least one electric motor control device; and the control unit is configured to control the electric motor control device for controlling the rotational speed of the electric motor and the hydraulic pump; wherein in response to the selected restricted operating mode, a restricted output flow rate of the hydraulic fluid is achieved under the control of the control unit; the motor is a speed-controlled electric motor controlled by means of a variable frequency drive serving as the electric motor control device; and the variable frequency drive includes an integrated safety function based on a hard-wired safety circuit.

[0007] The rock drilling equipment according to the invention is characterized by the following features: the hydraulic system is the above-mentioned hydraulic system, whereby the hydraulic drilling actuator of the rock drilling unit can be controlled in a restricted operating mode with limited performance.

[0008] The method according to the invention is characterized by the following features: the method includes driving the hydraulic pump by means of an electric motor (M); and controlling the rotational speed of the electric motor and the hydraulic pump to produce a restricted magnitude of the hydraulic fluid flow rate; wherein the motor is a speed-controlled electric motor controlled by means of a variable frequency drive serving as the electric motor control device; and the variable frequency drive includes an integrated safety function based on a hard-wired safety circuit.

[0009] The concept of the disclosed solution is that the hydraulic system of the rock drilling equipment includes at least one hydraulic circuit, the at least one hydraulic circuit being provided with a hydraulic power unit, the hydraulic power unit including a hydraulic pump driven by a motor. At least one hydraulic drilling actuator is powered by the hydraulic pressure and flow rate generated by the hydraulic power unit. In addition, the hydraulic system is provided with safety function features for restricting the characteristics of the input hydraulic fluid directed to the at least one hydraulic drilling actuator to temporarily limit the output performance of the hydraulic drilling actuator. And wherein the hydraulic system is provided with at least one control unit, the at least one control unit including at least one restricted operating mode (ROM), the at least one restricted operating mode serving as the safety function feature and being configured to limit the magnitude of the output flow rate of the pumping unit, whereby the movement speed of the drilling actuator is restricted due to the limited magnitude of the input flow rate received. The hydraulic pump is a fixed-displacement hydraulic pump driven by an electric motor. The electric motor is controlled by means of at least one electric motor control device, and the control unit is configured to control the electric motor control device for controlling the rotational speed of the electric motor and the hydraulic pump. In addition, in response to the selected restricted operating mode (ROM), a restricted output flow rate of the hydraulic fluid is achieved under the control of the control unit.

[0010] In other words, the output performance of the drilling actuator has been limited at the pumping unit, whereby a restriction valve or other control element connected to the hydraulic passage or at the drilling actuator is not required.

[0011] The advantage of the disclosed solution is that, since no external valves or valve assemblies are required in the system, pressure and power losses can be avoided. This applies to both the restricted operating mode and the normal drilling mode. In addition, the hydraulic circuit can be simple and can include fewer components.

[0012] Another advantage is that the present solution provides precise speed control for the controlled hydraulic drilling actuator during the ROM mode, which is beneficial not only for safety issues but also for operating measures.

[0013] According to one embodiment, the motor for driving the fixed displacement hydraulic pump is a speed-controlled electric motor controlled by a variable frequency drive, and the variable frequency drive serves as an electric motor control device for controlling the rotational speed of the electric motor.

[0014] According to one embodiment, the variable frequency drive includes an integrated safety function based on a hard-wired safety circuit.

[0015] According to one embodiment, the control unit is provided with at least one input limit value for the restricted operating mode (ROM). The input limit value is configured to define the maximum rotational speed of the rotary device of the rock drill and the drill tool that can be connected to the rock drill.

[0016] According to one embodiment, the input limit value defines the maximum amplitude of the output flow rate of the hydraulic fluid generated by the hydraulic pump and directed to at least one hydraulic actuator of the rock drill. The maximum flow rate is defined such that the maximum rotational speed cannot be exceeded.

[0017] According to one embodiment, the control unit is provided with at least one input limit value for the restricted operating mode (ROM). The input limit value is configured to define the maximum feed speed of the feed device of the rock drill and the drill tool that can be connected to the rock drill. The feed device can be a hydraulic motor or a hydraulic cylinder.

[0018] According to one embodiment, the input limit value defines the maximum amplitude of the output flow rate of the hydraulic fluid generated by the hydraulic pump and directed to at least one hydraulic actuator of the rock drill. The maximum flow rate is defined such that the maximum feed speed cannot be exceeded.

[0019] According to one embodiment, the control unit is configured to execute a restricted operation mode (ROM) in response to a received safety signal indicating the opening or activation of a safety device surrounding or connected to a rock drill.

[0020] According to one embodiment, the safety device is, for example, a safety door, a safety cage or a door of a noise damper. The safety device may be provided with one or more sensors for monitoring the state of the safety device. In addition, the safety device may include a safety wire and a safety switch connected to the safety wire.

[0021] According to one embodiment, the disclosed solution relates to a rock drilling equipment, which includes: a movable vehicle; at least one boom connected to the vehicle; at least one rock drilling unit mounted to the distal end of the boom, wherein the rock drilling unit includes a feed beam and a rock drill movably mounted on the feed beam. The rock drilling equipment further includes a hydraulic system, whereby the rock drill includes at least one hydraulic actuator powered by the hydraulic system. The hydraulic system is a hydraulic system according to the features and embodiments disclosed in this document, whereby the hydraulic actuator of the rock drill can be controlled in a restricted operation mode with limited performance.

[0022] According to one embodiment, the disclosed solution relates to a method for temporarily restricting the output performance of a hydraulic drilling actuator under the execution of a safety function feature in a hydraulic system. The method includes restricting the hydraulic characteristics of the hydraulic fluid inputted to the hydraulic drilling actuator connected to the hydraulic circuit of the hydraulic system. The output performance of the drilling actuator is restricted by restricting the hydraulic fluid flow generated in the hydraulic circuit of the hydraulic drilling actuator, whereby a restricted size of fluid flow is generated at the hydraulic pump of the hydraulic circuit during the duration of the restricted operation mode of the safety feature.

[0023] According to one embodiment, the disclosed restricted operation mode, i.e., the ROM mode, can be based on the requirements of standard EN16228 and may include the following measures:

[0024] Connection ROM mode

[0025] 1. The safety device is activated.

[0026] 2. The ROM mode is activated by means of a separate switch. The switch may be a physical switch device.

[0027] 3. When the ROM mode is in effect, the feed and / or rotation of the rock drill is actively controlled under the control of the control unit.

[0028] 4. The feed can be actively controlled at a maximum limit of 15 m / min, and the rotation can be actively controlled at a maximum limit of 30 rpm. Then, the movement of the rock drill is carried out at a sufficiently slow speed. This enables safe operation when the guard door or guard cage is open.

[0029] Stop the ROM mode and start the normal mode

[0030] 1. End the active control in the ROM mode.

[0031] 2. Deactivate the safety condition of the safety device. Reconnect the safety device to its protected state. For example, close the guard door or guard cage.

[0032] 3. Select the normal mode by means of the switching device.

[0033] 4. Continue operation in the normal mode without performance limitations.

[0034] The above disclosed embodiments can be combined in order to form a suitable solution having those features required among the above features. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Some embodiments are described in more detail in the drawings, in which

[0036] Figure 1 is a schematic view of a rock drilling equipment,

[0037] Figure 2 is a schematic hydraulic diagram of a hydraulic system provided with safety features as disclosed,

[0038] Figure 3 is another schematic hydraulic diagram of a hydraulic system provided with safety features, and

[0039] Figure 4 is a schematic diagram showing some features and principles of the disclosed solution.

[0040] For clarity, the drawings show some embodiments of the disclosed solution in a simplified manner. In the drawings, the same reference numerals identify the same elements. DETAILED DESCRIPTION

[0041] Figure 1There is shown a rock drilling equipment 1, which comprises a movable vehicle 2 and one or more booms 3 connected to the vehicle 2. The boom 3 may be provided with a rock drilling unit 4 including a feed beam 5, on which a rock drilling machine 6 is movably arranged. The rock drilling machine 6 may include an impact device 7 for providing a rock drilling tool 8 with impact pulses for breaking the rock material being drilled, and a rotation device 9 for rotating the drilling tool 8 about its longitudinal axis. By means of a feed device 10, the rock drilling machine 6 is moved in the drilling direction A and the reverse direction B. The rock drilling unit 4 may further include one or more safety devices Sd (such as a protective cage, cover, noise damper or safety line) to prevent the operator from approaching the rotating and moving machine elements.

[0042] Figure 1 There is further disclosed that the rock drilling equipment 1 includes a power unit Pu for generating a required pressurized hydraulic fluid flow to a hydraulically operable drilling actuator of the rock drilling unit 4. The rotation device 9 and the feed device 10 may be hydraulically operable drilling actuators driven by the power unit Pu and the impact device 7. There is also one or more control units CU, which may be provided with the safety features disclosed in this document.

[0043] Figure 1 There is disclosed a surface rock drilling equipment 1 for drilling blast holes, but the solution disclosed in this document can also be used in underground drilling and reinforcement devices, such as for rock bolting solutions.

[0044] Figure 2 There is disclosed a hydraulic system HS of the rock drilling equipment. The hydraulic system HS includes: a closed-loop hydraulic circuit CL having a first hydraulic power unit Pu1; and an open-loop hydraulic circuit OL having a second hydraulic power unit Pu2. The closed-loop hydraulic circuit CL includes a first hydraulic pump Hp1 driven by a first motor M1. A first hydraulic drilling actuator Ha1 is connected to the closed-loop hydraulic circuit CL. The first hydraulic drilling actuator Ha1 may be a rotation device. As Figure 1 shown, the pressurized hydraulic fluid is guided to circulate in the closed-loop hydraulic circuit CL from the outlet port of the first hydraulic pump Hp1 to the inlet port of the first hydraulic drilling actuator Ha1, and further from the outlet port of the first hydraulic actuator Ha1 to the inlet port of the first hydraulic pump Hp1. In Figure 1In it, the first hydraulic pump Hp1 and the first hydraulic drilling actuator Ha1 can rotate in two rotational directions. Therefore, for clarity reasons, the inlet port and the outlet port are not marked. The first motor M1 can be controlled by means of the electric motor controller Mc, and the control signal can be transmitted from the control unit CU to the electric motor controller Mc. The control unit CU can precisely and steplessly control, for example, the rotational speed of the first motor M1, and when the first hydraulic pump Hp1 is a fixed displacement pump, it can precisely control the hydraulic power output of the first hydraulic power unit Pu1. The control unit CU can include a ROM mode for interrupting the normal mode and allowing a limited duration of safe and slow movement of the first hydraulic actuator Ha1. This ROM mode can include a safety control program or algorithm, parameters, and limit values that can be input into the control unit CU. For example, the control unit CU can also receive safety signals from sensors and safety switches for detecting the status of different safety devices. The control unit can include a processor for executing the input control program and for generating the required control signals.

[0045] Figure 2 The open-loop hydraulic circuit OL of the hydraulic system includes a second hydraulic pump Hp2 driven by a second motor M2. The second hydraulic power unit Pu2 is configured to provide hydraulic power to the second hydraulic drilling actuator Ha2, which can be a hydraulic feed device. The feed device can be a hydraulic motor or a hydraulic cylinder. The open-loop hydraulic circuit OL can be a so-called common rail circuit, which can also provide hydraulic power to the auxiliary actuators of the rock drilling equipment. If a supplementary amount of hydraulic fluid is required therein, the hydraulic fluid can be selectively fed from the common rail circuit into the closed-loop circuit CL. This is shown in dashed lines in Figure 2 In it. Different from the closed-loop hydraulic circuit CL, the open-loop hydraulic circuit OL circulates the hydraulic fluid via the tank T or reservoir.

[0046] Figure 3 An alternative hydraulic system HS for providing hydraulic power to two hydraulic drilling actuators Ha1 and Ha2 is disclosed. The hydraulic circuits CL and OL are very similar to the hydraulic circuits shown in the previous Figure 2 In it. However, in Figure 3 In it, the second hydraulic power unit Pu2 of the open-loop hydraulic circuit OL is provided with safety feature control. Then, the second motor M2 can be controlled under the control of the control unit CU and the electric motor control unit Mc, or alternatively, the second hydraulic pump Hp2 can be a variable displacement pump, which can be controlled by means of the control unit CU for regulating the generated fluid flow rate.

[0047] Figure 4It is a summary diagram showing some basic features and alternatives of the disclosed solution. These problems have been disclosed above in this document.

[0048] The accompanying drawings and the related description are only intended to illustrate the concept of the present invention. In the detailed aspects of the present invention, the present invention can vary within the scope of the claims.

Claims

1. A hydraulic system (HS) of a rock drilling equipment (1), the rock drilling equipment comprising a rock drilling machine (6), the hydraulic system comprising: At least one hydraulic circuit (CL, OL) provided with a hydraulic power unit (Pu), the hydraulic power unit (Pu) comprising a hydraulic pump (Hp) driven by means of a motor (M); At least one hydraulic drilling actuator (Ha) powered by the hydraulic pressure and flow rate generated by the hydraulic power unit (Pu); Wherein the hydraulic system (HS) is provided with a safety function feature for restricting the characteristics of the input hydraulic fluid directed to the at least one hydraulic drilling actuator (Ha) to temporarily restrict the output performance of the hydraulic drilling actuator (Ha); and The hydraulic system (HS) is provided with at least one control unit (CU), the at least one control unit (CU) comprising at least one restricted operation mode (ROM), the at least one restricted operation mode (ROM) serving as the safety function feature and being configured to restrict the magnitude of the output flow rate of the hydraulic power unit (Pu), whereby the movement speed of the hydraulic drilling actuator (Ha) is restricted due to the limited magnitude of the input flow rate received, Characterized in that: The hydraulic pump (Hp) is a fixed displacement hydraulic pump driven by means of an electric motor (M); The electric motor (M) is controlled by means of at least one electric motor control device (Mc); and The control unit (CU) is configured to control the electric motor control device (Mc) for controlling the rotational speed of the electric motor (M) and the hydraulic pump (Hp); Wherein In response to the selected restricted operation mode (ROM), the restricted output flow rate of the hydraulic fluid is achieved under the control of the control unit (CU); The motor (M) is a speed control electric motor controlled by means of a variable frequency drive serving as the electric motor control device (Mc); and The variable frequency drive includes an integrated safety function based on a hardwired safety circuit.

2. The hydraulic system according to claim 1, characterized in that: The control unit (CU) is provided with at least one input limit value for the restricted operation mode (ROM); and The input limit value is configured to define the maximum rotational speed of the rotating device (9) of the rock drilling machine (6) and the drilling tool (8) that can be connected to the rock drilling machine (6).

3. The hydraulic system according to claim 1 or 2, characterized in that: The control unit (CU) is provided with at least one input limit value for the restricted operation mode (ROM); and The input limit value is configured to define the maximum feed speed of the feed device (10) of the rock drilling machine (6) and the drilling tool (8) that can be connected to the rock drilling machine (6).

4. A rock drilling equipment (1), comprising: A movable vehicle (2); At least one boom (3), the at least one boom (3) being connected to the vehicle (2); At least one rock drilling unit (4), said at least one rock drilling unit (4) being mounted to the distal end of the boom (3), wherein said rock drilling unit (4) comprises a feed beam (5) and a rock drilling machine (6) movably mounted on said feed beam (5); A hydraulic system (HS); And wherein said rock drilling machine (6) comprises at least one hydraulic drilling actuator (Ha) powered by said hydraulic system (HS); Characterized in that Said hydraulic system (HS) is the hydraulic system according to any one of the preceding claims 1 - 3, whereby the hydraulic drilling actuator (Ha) of said rock drilling unit (4) can be controlled in a restricted operating mode (ROM) with limited performance.

5. A method for temporarily restricting the output performance of a hydraulic drilling actuator (Ha) under the execution of a safety function feature of a hydraulic system (HS); Wherein the method comprises restricting a hydraulic characteristic of hydraulic fluid input to the hydraulic drilling actuator (Ha) that is directed to a hydraulic circuit (CL, OL) connected to the hydraulic system (HS); And Restricting the output performance of said hydraulic drilling actuator (Ha) by restricting the hydraulic fluid flow generated in the hydraulic circuit (CL, OL) of said hydraulic drilling actuator (Ha), whereby a restricted magnitude of said fluid flow is generated at the hydraulic pump (Hp) of said hydraulic circuit during the duration of the restricted operating mode of said safety feature, Characterized by comprising: Driving said hydraulic pump (Hp) by means of an electric motor (M); and Controlling the rotational speed of said electric motor (M) and said hydraulic pump (Hp) to generate a restricted magnitude of hydraulic fluid flow; Wherein Said motor (M) is a speed - controlled electric motor controlled by means of a variable - frequency drive serving as said electric motor control device (Mc); and Said variable - frequency drive comprises an integrated safety function based on a hard - wired safety circuit.

Images