A precision drive device for double-feed of the main slider of a numerically controlled cold ring rolling mill

Abstract

The present invention discloses a double-feed precision driving device for the main slider of a numerically controlled cold ring rolling mill, which relates to the field of cold ring rolling in metal pressure processing. The double-feed precision driving device for the main slider of the numerically controlled cold ring rolling mill includes a two-way main oil cylinder for driving the movement of the main slider, a main oil pump for supplying oil to the main oil cylinder, and a detection device for detecting the movement position of the main slider. The rodless cavity of the two-way main oil cylinder is connected to a servo booster oil pump, and when precision feeding is performed, the servo booster oil pump supplies oil to the rodless cavity of the main oil cylinder. In the double-feed precision driving device for the main slider of the numerically controlled cold ring rolling mill, the hydraulic oil pushes the piston of the main oil cylinder to perform leftward working feed, improving the stability of the machine tool and solving the problems of poor stability of the machine tool and low quality of the cold rolled and formed workpieces. When the solenoid valve electromagnet is in the state of 1YV+ (energized) and 2YV- (not energized), the system pressure oil enters the main oil cylinder at a low pressure, pushing the piston of the main oil cylinder to perform rapid feed during the idle stroke. The servo booster oil pump controls the slow working feed, solving the problem of sudden speed change during processing and the inadaptability of the motor.

Description

Technical Field

[0001] The present invention relates to the field of cold ring rolling in metal pressure processing, and particularly to a double-feed precision driving device for the main slider of a numerically controlled cold ring rolling machine. Background Art

[0002] Cold rolling is a cold working forming method in which a ring-shaped rotating part is continuously locally plastically deformed in a die cavity composed of a rolling wheel and a core roll at room temperature, so as to obtain a part close to the finished product. Its working principle is that an actively rotating rolling wheel forms the outer circle contour of the ring-shaped workpiece, and a driven core roll forms the shape of the inner surface of the ring-shaped workpiece.

[0003] The power for ring rolling is realized by a pair of supporting wheels installed on the slider being pushed by the piston rod of the oil cylinder to push the core roll. The rolling pressure required for cold rolling forming is usually above 20,000 kg, the idle stroke feed speed is 20 - 30 mm / s, and the working feed speed is 0.05 - 0.1 mm / s. Currently, it is mainly powered by hydraulic pressure, and the speed control relies on an electro-hydraulic proportional speed control valve. In actual production, due to the continuous working time, the temperature of the hydraulic oil will rise, and the feed speed varies greatly from 0.05 mm / s to 25 mm / s. There is often "non-linear" crawling at low speeds, the input current of the proportional valve is not proportional to the output flow, and the stability of the machine tool is poor.

[0004] A medium and large-sized numerically controlled ring rolling machine, with the research and design by Henan Chuangshi Technology Development Co., Ltd. and the application number CN201618824U, uses it throughout the entire cold rolling process to replace the proportional valve. Compared with the proportional valve, its stability is greatly improved. However, when the idle stroke feed speed is 20 - 30 mm / s and the working feed speed is 0.05 - 0.1 mm / s, the speed difference is hundreds of times. If the entire device is to meet both a large speed and a relatively small speed, there is a problem of mismatch. Therefore, in order to ensure that the device can adapt to both a large speed and a small speed, the present invention provides a double-feed precision driving device for the main slider of a numerically controlled cold ring rolling machine. Summary of the Invention

[0005] The technical problems to be solved by the present invention are that the working feed speed varies greatly, the stability of the machine tool is poor, the quality of the cold-rolled formed workpiece is low, the difference between the idle stroke feed speed and the working feed speed is too large, and the motor does not adapt to sudden speed changes. To solve the above problems, the present invention provides a double-feed precision driving device for the main slider of a numerically controlled cold ring rolling machine.

[0006] The purpose of the present invention is achieved in the following manner:

[0007] A double-feed precision driving device for the main slider of a numerically controlled cold ring rolling machine, comprising a two-way main oil cylinder for driving the movement of the main slider, a main oil pump for supplying oil to the main oil cylinder, and a detection device for detecting the moving position of the main slider. The rodless cavity of the two-way main oil cylinder is connected to a servo booster oil pump, and when precision feeding is required, the servo booster oil pump supplies oil to the rodless cavity of the main oil cylinder.

[0008] When precision feeding is required and the servo booster oil pump supplies oil to the rodless cavity of the main oil cylinder, it means that the rod cavity of the main oil cylinder is connected to an oil outlet of a two-position four-way electromagnetic directional control valve, and another oil outlet of the two-position four-way electromagnetic directional control valve is connected to the oil inlet of a two-position three-way electromagnetic directional control valve. The oil outlet of the two-position three-way electromagnetic directional control valve is respectively connected to the rodless cavity of the main oil cylinder and the servo booster oil pump through a three-way pipe. The two-position four-way electromagnetic directional control valve, the two-position three-way electromagnetic directional control valve, the main oil cylinder, the detection device, and the servo booster oil pump are respectively connected to a controller. When precision feeding is required, the oil outlet of the two-position three-way electromagnetic directional control valve is closed, and only the servo booster oil pump supplies oil to the rodless cavity of the main oil cylinder.

[0009] The servo booster oil pump is a servo booster oil pump body. One end of the servo booster oil pump body is provided with an oil inlet and outlet, and the other end of the servo booster oil pump body extends into a booster pump piston, and one end of a servo electric push rod is connected to the booster pump piston.

[0010] The diameter of the main oil cylinder piston is 2 - 6 times the diameter of the booster pump piston.

[0011] The diameter of the main oil cylinder piston is 2.5 times the diameter of the booster pump piston.

[0012] The detection device for detecting the moving position of the main slider is a proximity switch, and the proximity switch is connected to a controller.

[0013] A double-feed precision driving method for the main slider of a numerically controlled cold ring rolling machine, comprising the following steps:

[0014] (1) When the electromagnet of the two-position four-way electromagnetic directional control valve is in the 1YV+ state and the electromagnet of the two-position three-way electromagnetic directional control valve 2YV- is not energized, the system pressure oil enters the main oil cylinder through the rodless cavity at a low pressure of 20 kg / cm², pushing the main oil cylinder piston to move quickly. At the same time, the pressure oil enters the servo booster oil pump, pushing the booster pump piston back to the right extreme position, and the servo booster oil pump is filled with pressure oil.

[0015] (2) The main slider makes a quick idle feed. When the main slider reaches the working position, the proximity switch for detecting the position of the main slider sends a signal. The electromagnet of the two-position four-way electromagnetic directional control valve continues to be in the 1YV+ energized state, and at the same time, the electromagnet of the two-position three-way electromagnetic directional control valve 2YV+ is energized to cut off the main oil circuit. At this time, the booster pump piston is pushed to move by the servo electric push rod. In this case, the servo booster oil pump and the main oil cylinder form a closed oil cavity. Under the push of the booster pump piston, the hydraulic oil pushes the main oil cylinder piston to work and feed to the left for ring rolling.

[0016] (3) When the ring rolling ends, the electromagnet of the four-way two-position solenoid directional valve 1YV loses power, and the hydraulic oil enters through the rod chamber of the main oil cylinder, pushing the piston of the main oil cylinder to return quickly. The hydraulic oil in the rodless chamber of the main oil cylinder is pushed into the servo booster oil pump chamber, and the excess oil flows back to the oil tank through the solenoid valve. At the same time, it quickly retracts to complete one cycle.

[0017] Compared with the prior art, the double-feed precision drive device of the main slider of this CNC cold ring rolling machine can, when the main slider makes a rapid idle advance and reaches the working position, the proximity switch that detects the position of the main slider sends a signal, and the electromagnet of the four-way two-position solenoid directional valve remains in the 1YV+ energized state. At the same time, the electromagnet of the three-way two-position solenoid directional valve 2YV+ is energized to cut off the main oil circuit. At this time, the servo electric push rod is used to push the piston of the booster pump to move. Under the push of the piston of the booster pump, the hydraulic oil pushes the piston of the main oil cylinder to make a working feed to the left. The feed speed is stable, the stability of the machine tool is greatly improved, and the quality of the cold-rolled formed workpiece is high. It solves the problems of large variation in the working feed speed, poor stability of the machine tool, and low quality of the cold-rolled formed workpiece. At the same time, it is used in cooperation with the booster pump. When the electromagnet of the solenoid valve is in the state of 1YV+ (energized) and 2YV- (not energized), the system pressure oil enters the main oil cylinder through the rodless chamber of the oil cylinder at a low pressure (20 kg / cm²), pushing the piston of the main oil cylinder to move quickly for rapid feed during the idle stroke. The servo booster oil pump controls the slow forward movement during the working feed, solving the problem of sudden speed change during processing and the inadaptability of the motor. Description of the Drawings

[0018] Figure 1 It is a schematic diagram of the hydraulic control system of the double-feed precision drive device of the main slider of a CNC cold ring rolling machine.

[0019] Among them, 1 is the oil tank, 2 is the fixed-displacement hydraulic pump, 3 is the filter, 4 is the stop valve, 5 is the pressure gauge, 6 is the check valve, 7 is the check valve, 8 is the four-way two-position solenoid directional valve, 9 is the three-way two-position solenoid directional valve, 10 is the main oil cylinder, 11 is the piston of the main oil cylinder, 12 is the servo booster oil pump, 13 is the piston of the booster pump, 14 is the servo electric push rod, 15 is the piston rod, 16 is the guide sleeve, and 17 is the guide piston. Detailed Implementation Modes

[0020] Example 1:

[0021] As shown in the attached Figure 1 figures, a double-feed precision drive device for the main slider of a CNC cold ring rolling machine includes a two-way main oil cylinder 10 that drives the main slider to move, and a detection device that detects the position of the main slider. The rodless chamber of the two-way main oil cylinder 10 is connected to the servo booster oil pump 12, and when making a precision feed, the servo booster oil pump 12 supplies oil to the rodless chamber of the main oil cylinder 10.

[0022] When precisely feeding, the servo boost oil pump 12 supplies oil to the rodless cavity of the main cylinder 10, which means that the rod cavity of the main cylinder 10 is connected to an oil outlet of the two-position four-way electromagnetic directional valve 8, and the other oil outlet of the two-position four-way electromagnetic directional valve 8 is connected to the oil inlet of the two-position three-way electromagnetic directional valve 9. The oil outlet of the two-position three-way electromagnetic directional valve 9 is connected to the rodless cavity of the main cylinder 10 and the servo boost oil pump 12 respectively through a three-way pipe. The two-position four-way electromagnetic directional valve 8, the two-position three-way electromagnetic directional valve 9, the main cylinder 10, the detection device, and the servo boost oil pump 12 are respectively connected to the controller. When precisely feeding, the oil outlet of the two-position three-way electromagnetic directional valve 9 is closed, and only the servo boost oil pump 12 supplies oil to the rodless cavity of the main cylinder 10.

[0023] The servo boost oil pump 12 is a servo boost oil pump body. One end of the servo boost oil pump body is provided with an oil inlet and outlet, and the other end of the servo boost oil pump body extends into the boost pump piston 13. One end of the servo electric push rod 14 is connected to the boost pump piston 13. The servo electric push rod 14 is a combination of a transmission mechanism and a driving mechanism. The servo electric push rod 14 converts rotational motion into linear motion, and the servo electric push rod 14 can achieve precise speed control, precise revolution control, and precise torque control, which are transformed into precise speed control, precise position control, and precise thrust control. It is a new product of a high-precision linear motion series, with closed-loop servo control and a control accuracy of up to 0.01 mm. It can precisely control the thrust, add a pressure sensor, and the control accuracy can reach 1%. Moreover, the servo cylinder has low noise, energy-saving, cleanliness, high rigidity, impact resistance, and an extremely long service life. It is simple to operate and maintain. The servo electric push rod 14 can work without failure in a harsh environment, and the protection level can reach IP66 for long-term operation. It can achieve high strength, high speed, and high-precision positioning, with stable motion and low noise. Therefore, it can be widely applied in the automotive industry, electronics industry, mechanical automation industry, equipment assembly line industry, etc. The servo electric push rod 14 only needs to be regularly greased and lubricated when working in a complex environment, and there are no vulnerable parts that need to be maintained and replaced, which will reduce a large amount of after-sales service costs compared with hydraulic systems and pneumatic systems. The most important thing is that it is very easy to connect with control systems such as PLC to achieve high-precision motion control. The servo electric push rod 14 uses a servo motor inside instead of a stepper motor, mainly because it realizes closed-loop control of position, speed, and torque, overcomes the problem of stepper motor step loss, runs smoothly at low speeds, and does not produce the stepping operation phenomenon similar to stepper motors at low speeds. The dynamic response time of the motor during acceleration and deceleration is short, generally within dozens of milliseconds. Simply put, for the common motors often seen, after power-off, they will still rotate for a while due to their own inertia and then stop, while the servo motor and the stepper motor stop immediately when commanded to stop and start immediately when commanded to start, with extremely fast response. However, the stepper motor has the problem of step loss, so a servo motor is used.

[0024] The diameter of the main cylinder piston is 2 to 6 times that of the booster pump piston. The diameter of the main cylinder piston is 2.5 times that of the booster pump piston. The actual pressure increases by 2.5² = 6.25 times. The travel speed is easier to control by PLC. PLC is a programmable logic controller, a digital arithmetic controller with a microprocessor for automation control. It can load control instructions into memory for storage and execution at any time. The programmable controller consists of functional units such as CPU, instruction and data memory, input / output interface, power supply, digital-to-analog conversion, etc. Early programmable logic controllers only had the function of logic control, so they were named programmable logic controllers. Later, with continuous development, these originally simple computer modules already have various functions including logic control, timing control, analog control, multi-machine communication, etc., and the name has been changed to programmable controller. Since most PLCs use single-chip microcomputers, the integration degree is high. Coupled with the corresponding protection circuits and self-diagnosis functions, the reliability of the system is improved. One of the greatest advantages of PLC is that for different on-site signals (such as DC or AC, switch quantity, digital quantity or analog quantity, voltage or current, etc.), there are corresponding templates that can be directly connected to the devices in the industrial field (such as buttons, switches, sensor current transmitters, motor starters or control valves, etc.) and connected to the CPU main board through the bus. Compared with computer systems, PLC installation does not require a dedicated computer room or strict shielding measures. When in use, just correctly connect the detection devices, actuators and the I / O interface terminals of PLC, and it can work normally.

[0025] The driving method of the double-feed precision driving device of the main slider of the numerically controlled cold ring rolling machine includes the following steps:

[0026] (1) When the electromagnet of the two-position four-way electromagnetic directional valve 8 is in the state of 1YV+ and the electromagnet of the two-position three-way electromagnetic directional valve 9, 2YV-, is not energized, the system pressure oil enters the main cylinder 10 through the rodless cavity of the cylinder at a low pressure of 20 kg / cm², pushing the main cylinder piston 11 to move quickly. At the same time, the pressure oil enters the servo booster oil pump 12, pushing the booster pump piston 13 back to the right extreme position, and the servo booster oil pump 12 is filled with pressure oil;

[0027] (2) The main slider makes a fast empty stroke. When the main slider reaches the working position, the proximity switch for detecting the position of the main slider sends a signal. The electromagnet of the two-position four-way electromagnetic directional valve 8 continues to be in the energized state of 1YV+, and at the same time, the electromagnet of the two-position three-way electromagnetic directional valve 9, 2YV+, is energized to cut off the main oil circuit. At this time, the booster pump piston 13 is pushed to move by the servo electric push rod 14. In this case, the servo booster oil pump 12 and the main cylinder 10 form a closed oil cavity. Under the push of the booster pump piston 13, the hydraulic oil pushes the main cylinder piston 11 to work leftward for in-feed and perform ring rolling;

[0028] (3)When the ring rolling ends, the electromagnet 1YV of the four-way two-position electromagnetic directional valve 8 loses power. The hydraulic oil enters through the rod chamber of the main oil cylinder 10, pushing the piston 11 of the main oil cylinder to return quickly. The hydraulic oil in the rodless chamber of the main oil cylinder 10 is pushed into the chamber of the servo booster oil pump 12. The excess oil flows back to the oil tank 1 through the solenoid valve, and at the same time, it quickly retracts to complete one cycle.

[0029] The double-feed precision drive device of the main slider of this CNC cold ring rolling machine uses a fixed-displacement hydraulic pump. The oil absorption and discharge volumes at the same rotational speed are fixed. Compared with other hydraulic systems, it has the advantage of being easy to operate. Since its oil outlet is directly connected to the oil tank, there will be no pressure for a long time, which has the advantage of a high service life. This system uses a four-way two-position electromagnetic directional valve to control the main oil circuit of the hydraulic system. When the valve fails, there will be no situation where the rodless chamber is continuously pressurized, and the oil in the rod chamber of the oil cylinder cannot return to the oil tank, resulting in an extremely high pressure in the rod chamber under the boosting effect of the oil cylinder, improving the system safety. A two-way four-position directional valve is used to control the working feed process. There is no vibration and noise caused by the release of pressure when the valve opens due to the difference in the response speed of the directional valve, resulting in the two-way four-position directional valve opening first and the three-way four-position directional valve opening later, causing high pressure to be generated before the valve port is opened. Moreover, the control steps are reduced, the coherence of the working feed process and the change speed of the working feed process are increased, the complexity of the system pipeline is reduced, the pipeline length is reduced, thereby reducing the resistance of the system oil to return to the oil tank, improving the working speed. In addition, the two-way four-position directional valve has the advantage of low cost compared with the three-way four-position directional valve. Therefore, the main oil circuit is controlled by a two-way four-position electromagnetic directional valve, and an electromagnetic directional valve is installed at the same time for the directional output of the hydraulic oil. As Figure 1 shown in the structure, it is fixedly installed on the frame to prevent the components from shifting due to vibration during the processing, resulting in large deviations in dimensions.

[0030] The working process of the present invention is as follows: First, the electromagnet of the two-position four-way electromagnetic reversing valve 8 is in the energized state of 1YV+, and the electromagnet of the two-position three-way electromagnetic reversing valve 9, 2YV-, is not energized. The system pressure oil enters the main cylinder 10 through the rodless cavity of the cylinder at a low pressure of 20 kg / cm², pushing the piston 11 of the main cylinder to move quickly. At the same time, the pressure oil enters the servo booster oil pump 12, pushing the booster pump piston 13 back to the right extreme position, and the servo booster oil pump 12 is filled with pressure oil. Then the main slider moves forward quickly. When the main slider reaches the working position, the proximity switch detecting the position of the main slider sends a signal. The electromagnet of the two-position four-way electromagnetic reversing valve 8 continues to be in the energized state of 1YV+, and at the same time, the electromagnet of the two-position three-way electromagnetic reversing valve 9, 2YV+, is energized, cutting off the main oil circuit. At this time, the servo electric push rod 14 is used to push the booster pump piston 13 to move. In this case, the servo booster oil pump 12 and the main cylinder 10 form a closed oil cavity. Under the push of the booster pump piston 13, the hydraulic oil pushes the piston 11 of the main cylinder to do a working feed to the left for ring rolling. When the ring rolling is completed, the electromagnet 1YV- of the two-position four-way electromagnetic reversing valve 8 is de-energized, and the hydraulic oil enters through the rod cavity of the main cylinder 10, pushing the piston 11 of the main cylinder to return quickly. The hydraulic oil in the rodless cavity of the main cylinder 10 is pushed into the cavity of the servo booster oil pump 12, and the excess oil flows back to the oil tank 1 through the solenoid valve, and at the same time, it quickly retracts to complete one cycle.

[0031] The above is only the preferred embodiment of the present invention. It should be noted that for those skilled in the art, without departing from the overall concept of the present invention, several changes and improvements can still be made, and these should also be regarded as the protection scope of the present invention.

Claims

1. A double-feed precision driving device for the main slider of a numerically controlled cold ring rolling mill, comprising a two-way main oil cylinder for driving the movement of the main slider, a main oil pump for supplying oil to the two-way main oil cylinder, and a detection device for detecting the movement position of the main slider. It is characterized in that the rodless cavity of the two-way main oil cylinder is connected to a servo booster oil pump, and when precision feeding, the servo booster oil pump supplies oil to the rodless cavity of the two-way main oil cylinder; the statement that when precision feeding, the servo booster oil pump supplies oil to the rodless cavity of the two-way main oil cylinder means that the rod cavity of the two-way main oil cylinder is connected to an oil outlet of a two-position four-way electromagnetic reversing valve, and the other oil outlet of the two-position four-way electromagnetic reversing valve is connected to the oil inlet of a two-position three-way electromagnetic reversing valve. The oil outlet of the two-position three-way electromagnetic reversing valve is respectively connected to the rodless cavity of the two-way main oil cylinder and the servo booster oil pump through a three-way pipe; the two-position four-way electromagnetic reversing valve, the two-position three-way electromagnetic reversing valve, the two-way main oil cylinder, the detection device, and the servo booster oil pump are respectively connected to a controller. When precision feeding, the oil outlet of the two-position three-way electromagnetic reversing valve is closed, and only the servo booster oil pump supplies oil to the rodless cavity of the two-way main oil cylinder.

2. A double-feed precision driving device for the main slider of a numerically controlled cold ring rolling mill according to claim 1, It is characterized in that the servo booster oil pump is a servo booster oil pump body. One end of the servo booster oil pump body is provided with an oil inlet and outlet, and the other end of the servo booster oil pump body extends into a booster pump piston, and one end of a servo electric push rod is connected to the booster pump piston.

3. A double-feed precision driving device for the main slider of a numerically controlled cold ring rolling mill according to claim 2, It is characterized in that the diameter of the piston of the two-way main oil cylinder is 2-6 times the diameter of the piston of the booster pump.

4. A double-feed precision driving device for the main slider of a numerically controlled cold ring rolling mill according to claim 3, It is characterized in that the diameter of the piston of the two-way main oil cylinder is 2.5 times the diameter of the piston of the booster pump.

5. A double-feed precision driving device for the main slider of a numerically controlled cold ring rolling mill according to claim 1, It is characterized in that the detection device for detecting the movement position of the main slider is a proximity switch, and the proximity switch is connected to the controller.

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