Analysis of CYTC89Y2 Drilling Rig Control system and typical fault handling

The CYTC89Y2 fully hydraulic top hammer medium-long hole drilling rig produced by Hongyuan Hydraulic Machinery Co., Ltd. adopts EDS electrical direct control system, and the rock drilling propulsion system adopts 12VDC proportional amplifier and potentiometer-controlled electromagnetic proportional control valve. At the same time, it connects and unloads drill rods for propulsion, and fast push and fast retreat are controlled by throttle valve. This article mainly describes the system composition and technical parameters of the CYTC89Y2 deep hole drilling rig, and analyzes the faults that are more likely to occur during the operation of the rig. At the end of the article, corresponding solutions are proposed for the faults that occur. This article only discusses the propulsion system of the equipment during rock drilling.

0 Introduction

CYTC89Y2 fully hydraulic long hole drilling rig is suitable for medium and large-sized tunnel operations. The rig is equipped with a top hammer hydraulic rock drill, which can drill medium-deep holes with a diameter of 51 to 89 mm. The universal positioning configuration is suitable for production drilling in different mining methods. This type of rig integrates mechanical, electrical, gas, hydraulic, and internal combustion, with superior performance and complex structure. In the harsh working environment underground, the rig's faults are highly hidden, difficult to analyze, difficult to judge, and difficult to handle. Only by comprehensively and systematically mastering the structure and principle of the medium-deep hole drilling rig and constantly summarizing the fault laws in practice can we accurately analyze the faults and then handle them.

(1) The double shock-absorbing and buffering system of the HYG550 series rock drill can effectively absorb the recoil energy, maintain continuous and effective contact between the drill bit and the rock at the bottom of the hole, and increase the drilling rate. The pressure oil film protection and lubrication of the contact interface extend the maintenance interval and adapt to the drill tail of a given hole diameter.

(2) The drilling unit has an automatic rod handling system, a two-stage hydraulic cylinder propulsion beam, and front and rear tips installed on the propulsion beam. They can be used for guiding when drilling holes and for clamping when connecting and removing rods.

(3) Control system: EDS electrical direct control system, anti-drilling system.

1. Key components of hydraulic rig

(1) Rock drill is the heart of hydraulic rock drilling rig. The high-frequency reciprocating motion of the impact piston converts hydraulic energy into kinetic energy and transmits it to the drill bit. Due to the close contact between the drill bit and the rock, the impact kinetic energy is finally transmitted to the rock and breaks it. At the same time, in order to make the alloy column teeth repeatedly impact the same position to cause excessive rock crushing and reduce efficiency, the rock drill also needs to have a certain rotation speed. Its rotation speed is 200 r/min, that is, the rock drill must realize both impact and rotation.

(2) The impact and rotation of the thruster and rock drill are completed inside the rock drill. However, in addition to the impact and rotation, the rock drill needs to continuously push forward to complete the complete rock drilling action. This vertical movement along the push beam is completed by the thruster. The thruster is a component that guides the rock drill and the drill rod and keeps the drill bit in good contact during the rock drilling process. In order to ensure good contact between the drill bit and the rock during the rock drilling process, the thruster must have a certain pressure. The thrust pressure is provided by the A10V pump in the CYTC89 Y2 rig. The thrust force and the thrust speed are proportional under certain conditions. When the thrust force reaches a certain level, the thrust speed will not increase but decrease. If the thrust force is too small, the drill bit and the rock will have empty strikes, which will cause impact load fatigue to the components of the drill and rock drill and shorten their service life. If the thrust force is too high, the rod will deform and the drill will be damaged prematurely. This propulsion force also needs to control the rotational force during the propulsion process. When the drill rod passes through the cracks in the rock or other reasons cause the rotational pressure of the rock drill to suddenly increase, which may cause the caliper to jam, the propulsion force should be reduced immediately and the drill rod should be moved back. When the resistance drops to a certain level, normal drilling can be resumed. This function can reduce the consumption of drilling tools.

(3) The function of the hydraulic system of the rig is to optimize various drilling parameters according to the rock conditions to obtain the best rock drilling efficiency. It mainly controls various functions of the rock drill, such as rapid impact, rotation, propulsion and positioning. Some automatic functions are also completed by the hydraulic system, such as automatic anti-stuck function, automatic drilling stop, and drilling retraction function.

2 Analysis of propulsion system principle

This article only selects the propulsion system of the CYTC89 Y2 rock drilling rig to discuss how to combine hydraulics and electricity to deal with faults in the hydraulic system. The schematic diagram is shown in Figure 1:

The power source is driven by a 55kW motor to drive the A10V pump, and the system pressure is 210 bar. When the motor starts, in order to reduce the load at the start, an automatic unloading circuit is designed. When the motor starts, the solenoid valve Y156 loses power, and the high-pressure oil pumped by the A10V pump returns directly to the oil tank through the solenoid valve Y156, thereby reducing the load of the motor. When the motor starts, the solenoid valve Y156 is energized, and its valve core closes the oil circuit, and the high-pressure oil enters the load circuit. There are three control modes for the propulsion control circuit, namely, the fast propulsion mode, the loading and unloading needle rod working mode, and the rock drilling working mode. Fast energy feeding mode: the solenoid valve Y151A or Y151B is activated, and the hydraulic oil after the pressure adjustment enters the reversing valve directly without throttling, and enters the propulsion cylinder after passing through the reversing valve. Working mode of loading and unloading rod: Solenoid valve 149A or Y149B is actuated, and the high-pressure oil circuit passes through the pressure regulating valve and enters the pressure regulating valve after passing through a 20L/min throttle valve, and then enters the oil cylinder after passing through the pressure regulating valve. Working mode of rock drilling: Solenoid valve Y104A or Y1048 is actuated, and the high-pressure oil enters the reversing valve after passing through a 201/min throttle valve, and then enters the oil cylinder after passing through the reversing valve. Pressure control of propulsion system: During drilling, the propulsion pressure is adjusted using potentiometer R100 located on the control panel. The basic setting of propulsion pressure is only required when the propulsion adjustment function is abnormal or when the amplifier A1 changes. Before basic setting, verify that the voltage regulator U1 outputs a +10.0v voltage and check that there is a 24VDC voltage between terminals 1 and 2 of amplifier A1.

Before maintenance, make basic settings: connect the voltmeter to the test outlet of amplifier A1, turn the voltage knob counterclockwise to reach the minimum thrust pressure, and adjust l-b to 0 millivolts. Turn the voltage knob clockwise to reach the maximum thrust pressure, adjust l-s and l-m to 100 mA, start the pump and move the drilling control rod forward, adjust l-s, and the thrust pressure on the pressure gauge is about 15 bar. Screw the regulating valve C5 in several turns, keep the drilling control rod in the forward position, adjust l-m, and the thrust pressure on the pressure gauge GF is about 75 bar. Adjust the pressure regulating valve C5 to the required maximum thrust pressure of 60-70 bar, move the drilling control rod forward, adjust l-s and the thrust pressure on the pressure gauge GF is about 15 bar, screw the regulating valve in several turns, and keep the drilling control rod in the forward position. Adjust l-m, and the thrust pressure on the pressure gauge GF is about 75 bar. Adjust the pressure regulating valve C5 to the required maximum thrust pressure of about 60-70 bar. This is accomplished by three relief valves C1, C2, C3 and a solenoid proportional valve Y103 (Figure 4). Rapid push pressure control: When the joystick is turned to the rapid push position, the solenoid valve Y150B is energized, and the pressure passes through the reversing valve Y150 to the relief valve C4. The pressure of this relief valve is set to 50 bar. When the push pressure reaches 50 bar, the relief valve will operate to limit the pressure to 50 bar. Loading and unloading rod pressure control: When the joystick is turned to the loading and unloading rod position, the solenoid valve Y150C is energized, and the pressure oil passes through the solenoid valve Y150 to the relief valve C3. The pressure of this relief valve is set to 30 bar. When the pressure reaches 30 bar, the relief valve will operate to limit the pressure to 30 bar. Rock drilling pressure control: When the joystick is in rock drilling mode, solenoid valves Y150B and Y150C will not be energized, and the pressure oil will pass through the center hole of solenoid valve Y150 to the overflow valve C5 and solenoid valve Y103. Y103 is a proportional solenoid overflow valve, that is, the position of its valve core is controlled by the voltage, and its voltage is adjustable between 0 and 50VDC.

In Figure 4, U1 is a voltage regulator, A1 is a proportional amplifier, R100 is an adjustable resistor (0-1000 ohms), and Y103 is a proportional solenoid valve. When drilling upward, the normally open contact of relay K100 is closed. At this time, adjusting R100 can adjust the working pressure of solenoid valve Y103, thereby controlling the propulsion pressure when drilling upward.

3. Typical faults of propulsion system and their repair

Before inspecting the equipment, you should observe the working condition of the system, record the necessary data, ask the operator about the phenomena before and after the failure, make a list of the causes of the failure, conduct theoretical analysis, and then search for the fault. When searching, you should start with the easy ones and then move on to the difficult ones. Hydraulic components should be cleaned first and then replaced.

(1) Fault 1: No change in propulsion pressure when adjusting R100

① Fault analysis: This fault may be caused by the electrical part and the hydraulic part. Check the easy part first and then the difficult part. The electrical part may be caused by the failure of U1, A1 or R1, or the failure of the normally open contact of K100 to close.

② Fault inspection: First, the output voltage of U1 is measured to be 10.3V, which is normal. The output voltage across A1 is measured to be unchanged during the rotation of R100, and then R100 is measured, and it is found that the circuit between 1 and 3 of R100 is open.

③ Troubleshooting: The fault was eliminated after replacing R100. During long-term use, it was found that the original component was often damaged. The potentiometer was a winding type. After replacing it with a carbon film type, the fault rarely occurred.

(2) Fault 2: The propulsion pressure is 30 bar and does not change with the working status.

① Fault analysis: The electrical reason for this fault can only be that the solenoid valve Y150B is always energized, causing the overflow valve C3 to work all the time, limiting the pressure to 30 bar. The main reasons for this fault in the hydraulic aspect are the failure of the pressure regulating valve and the failure of the reversing valve Y150.

② Fault inspection: In accordance with the principle of starting with the easy and then the difficult, check the electrical aspects first. When the joystick is in the rock drilling state and the loading and unloading state, the solenoid valves Y150B and Y150C are energized respectively, indicating that the electrical control circuit of the solenoid valve Y150 is normal. Then check the hydraulic circuit. The most likely cause of the fault is the solenoid valve Y150. Open the solenoid valve Y150 and find that its oil channel is blocked by hydraulic oil crystals. From a theoretical analysis, the T port and the B port are blocked, and the pressure is limited to 30 bar by C3.

③Troubleshooting: Clean the solenoid valve Y150 and then install it to eliminate the fault.

(3) Fault 3: When the joystick is moved to the loading and unloading lever position, the rock drill only rotates without advancing.

① Fault analysis: Electrically, solenoid valves 149A and 149B are not energized. Hydraulically, overflow network C1 is stuck, and solenoid valve Y149 is stuck.

② Fault inspection: First check the electrical fault and find that the solenoid valves Y149A and Y149B are not powered. After inspection, it is found that the plug in the junction box was bent during the installation process because the socket was not aligned properly and the pin was not inserted into the hole, causing Y149 to lose power.

(4) Fault 4: A1 indicator light is off

① Fault analysis: At this time, it should be preliminarily determined that amplifier A1 is damaged, or power supply U1 is faulty. Power supply U1 cannot provide power to amplifier A1, causing the amplifier to fail to work.

② Fault inspection: Use a multimeter to measure the voltage of terminals 1~2 of power supply U1, which is 24VDC, and the voltage of terminals 3~4 is 10.3VDC. Power supply U1 works normally. The voltage between terminals 1~2 of amplifier A1 is 24VDC, which is normal. Adjust potentiometer R100 to measure amplifier A1, and the voltage between terminals 7~8 varies from 0~24VDC, which is normal. Then adjust potentiometer R100 clockwise to the maximum, and measure amplifier A1, and there is no voltage between terminals 3~4, which confirms that amplifier A1 is damaged.

③ Fault handling: After replacing amplifier A1, the voltage between terminals 3 and 4 was measured to be 0~13VDC. After starting the equipment, the function was normal. In this fault handling, there is another very interesting discovery. The solenoid valve plug has a power indicator light (light emitting diode), which will have a slight change in brightness with the adjustment of potentiometer R100. This small discovery provides valuable experience for future maintenance work and improves maintenance efficiency. The next time you encounter such a fault, adjust potentiometer R100, observe whether the power indicator light on the solenoid valve plug changes, and directly replace A1.

4 Conclusion

Through years of electrical maintenance experience, in modern engineering machinery equipment, the combination of hydraulics and electricity is becoming closer and closer, such as electromagnetic proportional control, PLC control, frequency converter, special module control, computer control, etc. Only by combining hydraulic and electrical control can the equipment be better maintained and repaired. The development speed of electrical control is very fast, and new products and new technologies emerge in an endless stream. Only by learning more and understanding more can we provide a theoretical basis for maintenance and repair work, so as to serve modern production. The new generation of rock drilling rigs newly produced by Hongyuan Hydraulic Machinery Co., Ltd. has added a control system for parameter setting, adjustment and maintenance of electrical and hydraulic systems, and added a large number of pressure sensors, temperature sensors, encoders, etc. for system control and positioning of equipment. Moreover, the control system is specially developed for the research and development of new rigs. A program module costs up to RMB 40,000, and there is no other product on the market that can replace it. For an electrical maintenance personnel, it is necessary to make accurate judgments and inspections. If you are not careful enough, the loss caused is very large. For this equipment, it is not just as simple as line maintenance. Therefore, as an electrical maintenance personnel, you must improve your knowledge and cannot be limited to the study of electrical systems. At the same time, you must master hydraulic and mechanical knowledge. The combination of hydraulics and electricity can better handle equipment failures and maintain the original working performance of the equipment.