Hydraulic feeding device and control method thereof

Abstract

The invention discloses a hydraulic feeding device and a control method thereof.The hydraulic feeding device comprises a variable-diameter hydraulic cylinder, a working system, a rapid propelling system, a slow propelling system and an auxiliary system, the variable-diameter hydraulic cylinder comprises a large-diameter hydraulic cylinder, a variable-diameter piston and a small-diameter hydraulic cylinder, the large-diameter hydraulic cylinder and the small-diameter hydraulic cylinder are coaxially and oppositely arranged, and the working system is connected with the working system; the variable-diameter piston comprises a piston rod in the middle and piston heads, the two ends of each piston head are matched with the large-diameter hydraulic cylinder and the small-diameter hydraulic cylinder respectively, the piston heads are arranged in the large-diameter hydraulic cylinder and the small-diameter hydraulic cylinder respectively, liquid is supplied to the large-diameter hydraulic cylinder to push the variable-diameter piston, and then the variable-diameter piston pushes the small-diameter hydraulic cylinder, so that the displacement is reduced, and meanwhile the feeding pressure is improved. The structure is simple, an indirect driving mode is adopted, the low-speed hydraulic pump pushes the piston in the large-diameter hydraulic cylinder, then the small-diameter hydraulic cylinder is pushed to supply liquid, and due to the fact that the areas of the two ends of the variable-diameter piston section are changed, the purpose of higher propelling pressure under small displacement is achieved.

Description

Technical Field

[0001] The invention belongs to the field of hydraulic control, and relates to a device for hydraulic propulsion in various industries such as engineering, automobiles, mining, and petroleum, and specifically to a hydraulic feeding device and a control method thereof. Background Art

[0002] The technology of pressure operation has irreplaceable technical advantages and has become the main engineering and technical means to improve and stabilize the production of a single well. However, since the production pipe is in a complex environment in the well for a long time, the connecting threads of the pipe are often rusted, and the buckle cannot be normally unfastened, making it impossible to achieve a complete set of pressure lifting pipe operation. In order to carry out the pressure operation normally, the oil pipe must be sealed and cut. When cutting the pipe, the pressure cutting tool must meet the requirements of smooth incision to facilitate the lifting of the pipe again, so the feed speed must be low and stable and the thrust must be sufficient.

[0003] The utility model patent with patent publication number CN203018823U discloses a pressure-operated cutting tool. The pressure-operated cutting tool works in conjunction with a pressure-operated machine to perform pressure-operated cutting on complex pipes and pull them out in sections, ensuring the smooth implementation of pressure-operated operations. The cutter of the device is installed on a feed hydraulic cylinder from the inside of the cutting chamber, and the feed hydraulic cylinder is installed on a rotating seat. The rotating seat is connected to the driving shaft through a gear. When in use, the cutter rotates with the rotating seat driven by the driving shaft. At the same time, by controlling the pressure difference between the oil filling port and the cutting chamber interface, the cutter head moves radially to achieve feed, thereby completing the cutting operation.

[0004] However, this patent uses a variable frequency motor to drive the electric cylinder to push the hydraulic cylinder to achieve the feeding needs, but due to the characteristics of the variable frequency motor itself, its torque is reduced under low frequency conditions, making it difficult to achieve the purpose of low-speed and smooth cutting.

[0005] The utility model patent with patent publication number CN216589413U discloses a high-low pressure feed hydraulic control system, which relates to the field of hydraulic control technology, including a low-pressure flow pump and a high-pressure flow pump, the liquid inlet port of the low-pressure flow pump is fixedly connected to the first liquid inlet pipe, the liquid outlet port of the low-pressure flow pump is fixedly connected to the first circulation pipe, the end of the first circulation pipe away from the low-pressure flow pump is fixedly connected to the inside of the first oil hydraulic cylinder, and the liquid inlet port of the high-pressure flow pump is fixedly connected to the second liquid inlet pipe.

[0006] This patent uses a high-pressure flow pump to provide high pressure for the hydraulic system. However, the high-pressure flow pump has problems such as unstable flow, being larger than a centrifugal pump at the same flow, having a complex structure, requiring large amounts of capital, and being difficult to maintain.

[0007] Therefore, there is an urgent need for a hydraulic propulsion device with adjustable feed speed, which is required to have high propulsion pressure under micro-feed state and can also be applied to other similar working conditions requiring small-displacement and high-pressure propulsion. Summary of the invention

[0008] The purpose of the present invention is to solve the problem that the propulsion pressure is insufficient due to the small torque of the variable frequency motor in the low-frequency state, and it is difficult to achieve micro-feeding under high pressure, resulting in the inability of the pressure-carrying cutting tool to complete low-speed and smooth cutting. A hydraulic feeding device and a control method thereof are provided, which have the characteristics of high pressure under small displacement conditions, large displacement adjustment range, and easy use.

[0009] In order to achieve the above-mentioned object of the invention, the technical solution of the present invention is as follows: A hydraulic feeding device, comprising A variable diameter cylinder, the variable diameter cylinder comprises a large diameter cylinder, a variable diameter piston and a small diameter cylinder, the large diameter cylinder and the small diameter cylinder are coaxially arranged opposite to each other, the variable diameter piston comprises a piston rod in the middle and piston heads respectively matched with the large diameter cylinder and the small diameter cylinder at both ends, the piston heads are respectively arranged in the large diameter cylinder and the small diameter cylinder, the variable diameter piston is pushed by supplying liquid to the large diameter cylinder, and the variable diameter piston pushes the small diameter cylinder to reduce the displacement and increase the feed pressure at the same time; The working system includes an oil inlet on-off valve, a working fluid cylinder and an oil return on-off valve. The oil inlet on-off valve is connected to the oil outlet of the small-diameter fluid cylinder through one end of a hydraulic pipeline, and the other end of the oil inlet on-off valve is connected to the oil inlet of the working fluid cylinder. The oil outlet of the working fluid cylinder is connected to the oil return on-off valve. The working fluid cylinder includes a push cylinder position and a retract cylinder position. The working system is suitable for various working conditions requiring hydraulic propulsion, especially for working conditions requiring small displacement and high pressure. For example, when the above-mentioned pressure-operated cutting tool cuts the pipe column, it is necessary to meet the requirements of a smooth incision and easy lifting of the pipe column again, so the feed is required to be slow and stable and have sufficient thrust. The working fluid cylinder is the final execution device of the system, which can be flexibly arranged according to actual working conditions, and is connected to a slow propulsion system and a fast propulsion system through a hydraulic pipeline to achieve different propulsion speeds.

[0010] A fast-forwarding system, the fast-forwarding system comprising a fast-forwarding stop valve, a fast-forwarding hydraulic pump and a fast-forwarding pump on-off valve, the oil outlet of the fast-forwarding hydraulic pump, the on-off valve of the fast-forwarding pump, the fast-forwarding stop valve and the oil outlet of the small-diameter hydraulic cylinder are connected in sequence through hydraulic pipelines, a tee is installed on the hydraulic pipeline between the on-off valve of the fast-forwarding pump and the fast-forwarding stop valve, and is connected to the oil outlet of the large-diameter hydraulic cylinder through a hydraulic pipeline, the fast-forwarding system can realize the rapid advancement of the working hydraulic cylinder or the rapid retreat of the variable-diameter piston; A slow propulsion system, the slow propulsion system comprises a slow hydraulic pump and a slow reversing valve, the oil outlet of the slow hydraulic pump and the slow reversing valve are connected through a hydraulic pipeline, the outlet pipeline of the slow reversing valve is respectively connected to the oil inlet and the oil outlet of the large-diameter hydraulic cylinder, the slow hydraulic pump uses a hydraulic pump with a smaller displacement than the fast hydraulic pump, and the power source uses a variable frequency motor, and the hydraulic pump displacement can be further adjusted by frequency modulation; The auxiliary system comprises a hydraulic oil tank, which is respectively connected to a slow-forward reversing valve, a slow-forward hydraulic pump, a fast-forward hydraulic pump, a fast-forward stop valve and an oil return on-off valve through hydraulic pipelines.

[0011] Furthermore, the variable diameter cylinder is also provided with a displacement scale, which is arranged at the end position of the large diameter cylinder near the variable diameter piston side, and is used to monitor the position of the variable diameter piston in real time to prevent the piston from hitting the cylinder end.

[0012] Furthermore, a one-way valve is provided on the pipeline between the oil inlet on-off valve and the working fluid cylinder of the working system to prevent the oil inlet on-off valve from being unable to be completely closed, resulting in hydraulic oil reflux and making it difficult to maintain the propulsion pressure of the working fluid cylinder.

[0013] Furthermore, a visual exhaust device is provided between the return oil on-off valve and the hydraulic oil tank of the working system, and bubbles in the return oil can be observed through its glass window to determine whether air has entered and exhaust the gas in the working fluid cylinder.

[0014] Furthermore, a return oil pressure sensor is provided in the pipeline between the oil outlet of the working cylinder of the working system and the return oil on-off valve, and a return oil speed regulating valve is provided in the pipeline between the return oil on-off valve and the hydraulic oil tank. The return oil flow rate can be controlled by operating the return oil speed regulating valve to prevent the return oil containing high-pressure gas from being quickly ejected from the exhaust port of the visible exhaust device.

[0015] Furthermore, a fast-forward pressure gauge and a fast-forward overflow valve are installed in the pipeline between the oil outlet of the fast-forward hydraulic pump of the rapid propulsion system and the hydraulic oil tank. The fast-forward overflow valve can ensure that the pump outlet hydraulic pipeline is safe and not over-pressurized when the fast-forward hydraulic pump is accidentally opened when the fast-forward pump on-off valve is not opened.

[0016] Furthermore, an oil inlet pressure sensor and a safety relief valve are provided in the pipeline between the fast-forward stop valve and the oil outlet of the small-diameter hydraulic cylinder of the rapid propulsion system. By adjusting the overflow value of the safety relief valve, the working system and the hydraulic pipeline can be ensured to be safe from overpressure.

[0017] Furthermore, the slow-feed hydraulic pump oil outlet is installed with a slow-feed pressure gauge and a slow-feed overflow valve, and the slow-feed overflow valve can ensure that the pump outlet hydraulic pipeline is safe from overpressure when the fast-feed hydraulic pump is opened by mistake without opening the fast-feed pump on-off valve.

[0018] Furthermore, the visual exhaust device, safety relief valve, fast-forward relief valve, slow-forward reversing valve, and slow-forward relief valve are installed on the upper cover of the hydraulic oil tank to facilitate oil return while reducing the space occupied by the device.

[0019] The frequency of the variable frequency motor (BM) of the slow-feed hydraulic pump is used to further fine-tune the propulsion speed in the slow-feed state.

[0020] A control method for a hydraulic feed device includes the following five working states: a slow advancing state, a fast advancing state, a fast retracting variable-diameter piston state, a slow retracting variable-diameter piston state, and a circulating exhaust state.

[0021] The slow propulsion state control steps are as follows: 1) Turn on the power of the device; 2) Adjust the slow-forward reversing valve to the push cylinder position; 3) Open the oil inlet on-off valve; 4) Close the fast-feed pump on-off valve, fast-feed stop valve, and oil return on-off valve respectively; 5) After checking that the valve position is correct, turn on the slow-feed hydraulic pump to slowly advance the working cylinder; 6) Further fine-tune the propulsion speed in the slow propulsion state by adjusting the frequency of the variable frequency motor supporting the slow-feed hydraulic pump.

[0022] The control steps in the fast advancement state are as follows: 1) Turn on the power of the device; 2) Adjust the slow-moving reversing valve to the middle position; 3) Open the fast-feed pump on-off valve, fast-feed stop valve, and oil inlet on-off valve respectively; 4) Close the oil return on-off valve; 5) After checking that the valve position is correct, turn on the fast-forward hydraulic pump to start rapidly advancing the working hydraulic cylinder.

[0023] The control steps for the rapid return of the variable diameter piston state are as follows: 1) When the reducing piston in the reducing cylinder moves to the right end, its stroke has been completed, and the reducing piston 1.2 needs to be returned to the left end to advance again; 2) Turn on the power of the device and adjust the slow-advance reversing valve to the middle position; 3) Open the fast-feed pump on-off valve and fast-feed stop valve respectively; 4) Close the oil inlet on-off valve and the oil return on-off valve respectively; 5) After checking that the valve position is correct, turn on the fast-forward hydraulic pump and begin to quickly retract the reducing piston until it is pushed to the left end and stops.

[0024] The control steps for the slow return of the variable diameter piston are as follows: 1) When the variable diameter piston in the variable diameter cylinder moves to the right end, it starts to retract; 2) Turn on the power of the device and adjust the slow-forward reversing valve to the cylinder retraction position; 3) Open the fast-forward stop valve; 4) Close the oil inlet on-off valve, oil return on-off valve, and fast feed pump on-off valve respectively; 5) After checking that the valve position is correct, start the slow-forward hydraulic pump and slowly retract the reducer piston until it is pushed to the left end and stops. The control steps in the cycle exhaust state are as follows: 1) When the working fluid cylinder is used for the first time, has not been used for a long time, or is otherwise judged to have bubbles inside, it should be circulated and exhausted; 2) Turn on the power of the device and adjust the slow-advance reversing valve to the middle position; 3) Open the fast-feed pump on-off valve, fast-feed stop valve, oil inlet on-off valve, and oil return on-off valve respectively; 4) After checking that the valve position is correct, start the fast-forward hydraulic pump to start circulating exhaust; 5) During the cycle, pay attention to the oil return status displayed on the glass window of the visual exhaust device; 6) Stop exhausting after observing that there are no bubbles in the glass window of the visual exhaust device; 7) After standing for 30 minutes, circulate the exhaust again according to the above steps until there are no bubbles in the return oil.

[0025] Beneficial effects of the present invention: 1. The present invention has a simple structure and adopts an indirect drive form. The slow hydraulic pump pushes the piston in the large-diameter cylinder, which in turn pushes the small-diameter cylinder to supply liquid. Due to the change in the cross-sectional area at both ends of the variable-diameter piston, the purpose of higher propulsion pressure under small displacement is achieved. The problem of insufficient propulsion pressure and difficulty in achieving high-pressure micro-feeding caused by the reduction of torque under low-frequency state due to direct drive of the variable-frequency motor is avoided.

[0026] 2. In the present invention, fast and slow propulsion speeds can be achieved by changing different propulsion systems in the system. Further fine-tuning of the propulsion speed can also be achieved by adjusting the speed of the variable frequency motor in the slow propulsion system. It can be used in a variety of working conditions.

[0027] 3. In the present invention, the working hydraulic cylinder is connected to other parts of the system through hydraulic pipelines. In practical applications, the various devices in the system can be set to different positions according to specific working conditions, and hydraulic pipelines of different lengths can be selected for connection, which has the characteristics of flexible layout and strong applicability.

[0028] 4. In the present invention, a relief valve is provided at the outlet of each hydraulic pump, and a safety relief valve is provided at the outlet high-pressure end of the variable diameter hydraulic cylinder, which can protect the pipelines, joints, etc. in the system, and is safe and reliable to use.

[0029] 5. In the present invention, by changing different propulsion systems in the system, fast and slow cylinder withdrawal can be achieved. When fast cylinder withdrawal fails and cannot be achieved, slow cylinder withdrawal can be used to withdraw the piston of the variable diameter hydraulic cylinder. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 It is a structural schematic diagram of the hydraulic feeding device of the present invention; Figure 2 It is a structural schematic diagram of the hydraulic feeding device of the present invention in a slow-speed advancing state; Figure 3 It is a structural schematic diagram of the hydraulic feeding device of the present invention in a rapid advancing state; Figure 4 It is a structural schematic diagram of the hydraulic feeding device of the present invention in a rapid retraction state; Figure 5 It is a structural schematic diagram of the hydraulic feeding device of the present invention in a slow retracting state; Figure 6 It is a schematic diagram of the slow structure of the circulating exhaust state of the hydraulic feeding device of the present invention.

[0031] Among them, 1. variable diameter cylinder; 2. working system; 3. fast propulsion system; 4. slow propulsion system; 5. auxiliary system; 1.1. large diameter cylinder; 1.2. variable diameter piston; 1.3. displacement scale; 1.4. small diameter cylinder; 2.1. oil inlet on-off valve; 2.2. one-way valve; 2.3. working cylinder; 2.4. return oil pressure sensor; 2.5. return oil on-off valve; 2.6. return oil speed regulating valve; 2. 7. Visual exhaust device; 3.1. Oil inlet pressure sensor; 3.2. Safety relief valve; 3.3. Fast-forward stop valve; 3.4. Fast-forward pressure gauge; 3.5. Fast-forward relief valve; 3.6. Fast-forward hydraulic pump; 3.7. Fast-forward pump on-off valve; 4.1. Slow-forward hydraulic pump; 4.2. Slow-forward reversing valve; 4.3. Slow-forward relief valve; 4.4. Slow-forward pressure gauge; 5.1. Hydraulic oil tank; 5.2. Hydraulic pipeline. DETAILED DESCRIPTION

[0032] In order to further understand the present invention, the specific implementation method of the present invention is described below in conjunction with embodiments.

[0033] It should be noted that the structures, proportions, sizes, etc. shown in this specification are only used to match the contents disclosed in the specification so that people familiar with this technology can understand and read them, and are not used to limit the conditions under which the present invention can be implemented. Any structural modification, change in proportional relationship or adjustment of size should fall within the scope of the technical content disclosed in the present invention without affecting the effects and purposes that can be achieved by the present invention.

[0034] At the same time, the terms such as "upper", "lower", "left", "right", "middle" and "one" cited in this specification are only for the convenience of description and are not used to limit the scope of implementation of the present invention. Changes or adjustments to their relative relationships should be regarded as the scope of implementation of the present invention without substantially changing the technical content.

[0035] Example 1 like Figure 1 , 2 As shown in Figure 5, a hydraulic feeding device comprises a variable diameter cylinder 1, a working system 2, a fast propulsion system 3, a slow propulsion system 4 and an auxiliary system 5. The variable diameter cylinder 1 comprises a large diameter cylinder 1.1, a variable diameter piston 1.2 and a small diameter cylinder 1.4. The large diameter cylinder 1.1 and the small diameter cylinder 1.4 are coaxially arranged opposite to each other. The variable diameter piston 1.2 comprises a piston rod in the middle and piston heads at both ends respectively matched with the large diameter cylinder 1.1 and the small diameter cylinder 1.4. The piston heads are respectively arranged in the large diameter cylinder 1.1 and the small diameter cylinder 1.4. The variable diameter piston 1.2 is pushed by supplying liquid to the large diameter cylinder 1.1, and the variable diameter piston 1.2 pushes the small diameter cylinder 1.4. 4, thereby achieving the purpose of reducing displacement and increasing feed pressure at the same time; the working system 2 includes an oil inlet on-off valve 2.1, a working fluid cylinder 2.3 and an oil return on-off valve 2.5, the oil inlet on-off valve 2.1 is connected to the oil outlet of the small-diameter fluid cylinder 1.4 through a hydraulic pipeline 5.2 at one end, and is connected to the oil inlet of the working fluid cylinder 2.3 at the other end, the oil outlet of the working fluid cylinder 2.3 is connected to the oil return on-off valve 2.5, the working fluid cylinder 2.3 includes a push cylinder position and a retract cylinder position; the fast advancing system 3 includes a fast forward stop valve 3.3, a fast forward fluid The oil outlet of the fast-forward hydraulic pump 3.6, the fast-forward pump on-off valve 3.7, the fast-forward stop valve 3.3 and the oil outlet of the small-diameter hydraulic cylinder 1.4 are connected in sequence through a hydraulic pipeline 5.2. A three-way is installed on the hydraulic pipeline 5.2 between the fast-forward pump on-off valve 3.7 and the fast-forward stop valve 3.3, and is connected to the oil outlet of the large-diameter hydraulic cylinder 1.1 through the hydraulic pipeline 5.2; the slow propulsion system 4 includes a slow-forward hydraulic pump 4.1 and a slow-forward reversing valve 4.2, the slow-forward hydraulic pump 3.6 oil outlet, the fast-forward pump on-off valve 3.7, the fast-forward stop valve 3.3 and the small-diameter hydraulic cylinder 1.4 oil outlet. The oil outlet of the hydraulic pump 4.1 and the slow-advance reversing valve 4.2 are connected through a hydraulic pipeline 5.2. The outlet pipeline of the slow-advance reversing valve 4.2 is respectively connected to the oil inlet and oil outlet of the large-diameter hydraulic cylinder 1.1. The power source of the slow-advance hydraulic pump 4.1 is a variable-frequency motor. The auxiliary system 5 includes a hydraulic oil tank 5.1. The hydraulic oil tank 5.1 is connected to the slow-advance reversing valve 4.2, the slow-advance hydraulic pump 4.1, the fast-advance hydraulic pump 3.6, the fast-advance stop valve 3.3 and the return oil on-off valve 2.5 through a hydraulic pipeline 5.2.

[0036] In this embodiment, slow propulsion is used under working conditions that require small displacement and high pressure. For example, when the above-mentioned pressure-operated cutting tool cuts the pipe string, it is necessary to meet the requirements of a smooth incision and easy lifting of the pipe string again. The use of slow propulsion can achieve a slow and stable feed speed and high thrust during cutting; when the variable diameter piston of the variable diameter hydraulic cylinder moves to the right end, the piston of the variable diameter hydraulic cylinder can be retracted by slow cylinder retraction.

[0037] The slow advancing state and slow retracting state of the hydraulic feed device are controlled by the following steps: 1) Turn on the power of the device; 2) Adjust the slow-forward reversing valve 4.2 to the push cylinder position; 3) Open the oil inlet on-off valve 2.1; 4) Close the fast-feed pump on-off valve 3.7, the fast-feed stop valve 3.3, and the return oil on-off valve 2.5 respectively; 5) After checking that the valve position is correct, start the slow-feed hydraulic pump 4.1 to slowly advance the working hydraulic cylinder 2.3; 6) Further fine-tune the propulsion speed in the slow propulsion state by adjusting the frequency of the variable frequency motor of the slow-feed hydraulic pump 4.1; 7) When the variable diameter piston 1.2 in the variable diameter cylinder 1 moves to the right end, the cylinder starts to be withdrawn; 8) Turn on the power supply of the device and adjust the slow-forward reversing valve 4.2 to the cylinder retraction position; 9) Open the fast-forward stop valve 3.3; 10) Close the oil inlet on-off valve 2.1, the oil return on-off valve 2.5, and the fast feed pump on-off valve 3.7 respectively; 11) After checking that the valve position is correct, start the slow-feed hydraulic pump 4.1 and start to slowly retract the reducing piston 1.2 until it is pushed to the left end and stops.

[0038] Example 2 like Figure 1 , 3 As shown in Figure 4, the difference between this embodiment and embodiment 1 is that the variable diameter cylinder 1 is further provided with a displacement scale 1.3, and the displacement scale 1.3 is arranged at the end position of the large diameter cylinder 1.1 near the variable diameter piston 1.2 side, a one-way valve 2.2 is arranged on the pipeline between the oil inlet on-off valve 2.1 of the working system 2 and the working cylinder 2.3, a fast-forward pressure gauge 3.4 and a fast-forward overflow valve 3.5 are installed on the pipeline between the oil outlet of the fast-forward hydraulic pump 3.6 of the fast-forward system 3 and the hydraulic oil tank 5.1, an oil inlet pressure sensor 3.1 and a safety overflow valve 3.2 are arranged on the pipeline between the fast-forward stop valve 3.3 of the fast-forward system 3 and the oil outlet of the small diameter cylinder 1.4, and the remaining structure is the same as that of embodiment 1.

[0039] In this embodiment, the displacement scale 1.3 is used to monitor the position of the variable diameter piston 1.2 in real time to prevent the piston from hitting the end of the cylinder; the one-way valve 2.2 prevents the oil inlet on-off valve 2.1 from being unable to be completely closed, and the hydraulic oil refluxes, which makes it difficult to maintain the propulsion pressure of the working cylinder 2.3; the fast-forward relief valve 3.5 can ensure that the pump outlet hydraulic pipeline 5.2 is safe from overpressure when the fast-forward hydraulic pump 3.6 is opened by mistake when the fast-forward pump on-off valve 3.7 is not opened; by adjusting the overflow value of the safety relief valve 3.2, the working system 2 and the hydraulic pipeline 5.2 can be ensured to be safe from overpressure; In this embodiment, rapid advancement is used under conditions where the working fluid cylinder needs to advance at a faster speed. For example, when the above-mentioned pressure-operated cutting tool cuts the pipe string, rapid advancement can be performed before the cutting tool contacts the pipe string to be cut to save time. When the variable diameter piston of the variable diameter fluid cylinder moves to the right end, the piston of the variable diameter fluid cylinder can be retracted by rapid cylinder withdrawal. Rapid cylinder withdrawal can save operation time and improve efficiency.

[0040] The rapid advance and rapid retraction states of the hydraulic feed device are controlled by the following steps: 1) Turn on the power of the device; 2) Adjust the slow-advance reversing valve 4.2 to the middle position; 3) Open the fast-feed pump on-off valve 3.7, the fast-feed stop valve 3.3, and the oil inlet on-off valve 2.1 respectively; 4) Close the oil return on-off valve 2.5; 5) After checking that the valve position is correct, turn on the fast-forward hydraulic pump 3.6 to start rapidly advancing the working hydraulic cylinder 2.3; 6) When the variable diameter piston 1.2 in the variable diameter cylinder 1 moves to the right end, its travel has been completed, and the variable diameter piston 1.2 needs to be returned to the left end to advance again; 7) Turn on the power supply of the device and adjust the slow-advance reversing valve 4.2 to the middle position; 8) Open the fast-feed pump on-off valve 3.7 and the fast-feed stop valve 3.3 respectively; 9) Close the oil inlet on-off valve 2.1 and the oil return on-off valve 2.5 respectively; 10) After checking that the valve position is correct, start the fast-forward hydraulic pump 3.6 to quickly retract the reducing piston 1.2 until it is pushed to the left end and stops.

[0041] Example 3 like Figure 1 , 2 As shown in FIG. 4 , the difference between this embodiment and embodiment 1 is that a slow-advance pressure gauge 4.4 and a slow-advance overflow valve 4.3 are installed at the oil outlet of the slow-advance hydraulic pump 4.1, and the remaining structures are the same as those of embodiment 1.

[0042] In this embodiment, the slow-feed relief valve 4.3 can ensure that the pump outlet hydraulic pipeline 5.2 is safe from overpressure when the fast-feed hydraulic pump 3.6 is opened by mistake without opening the fast-feed pump on-off valve 3.7.

[0043] In this embodiment, slow advancement is used under working conditions that require small displacement and high pressure. For example, when the above-mentioned pressure-operated cutting tool cuts the pipe column, it is necessary to meet the requirements of smooth incision and easy lifting of the pipe column again. The use of slow advancement can achieve a slow and stable feed speed and high thrust during cutting; when the variable diameter piston of the variable diameter hydraulic cylinder moves to the right end, the piston of the variable diameter hydraulic cylinder can be retracted by rapid cylinder withdrawal. Rapid cylinder withdrawal can save operation time and improve efficiency.

[0044] The slow advancing state and fast retracting state of the hydraulic feed device are controlled by the following steps: 1) Turn on the power of the device; 2) Adjust the slow-forward reversing valve 4.2 to the push cylinder position; 3) Open the oil inlet on-off valve 2.1; 4) Close the fast-feed pump on-off valve 3.7, the fast-feed stop valve 3.3, and the return oil on-off valve 2.5 respectively; 5) After checking that the valve position is correct, start the slow-feed hydraulic pump 4.1 to slowly advance the working hydraulic cylinder 2.3; 6) The propulsion speed in the slow propulsion state can be further fine-tuned by adjusting the frequency of the variable frequency motor supporting the slow-feed hydraulic pump 4.1; 7) When the variable diameter piston 1.2 in the variable diameter cylinder 1 moves to the right end, its travel has been completed, and the variable diameter piston 1.2 needs to be returned to the left end to advance again; 8) Turn on the power supply of the device and adjust the slow-advance reversing valve 4.2 to the middle position; 9) Open the fast-feed pump on-off valve 3.7 and the fast-feed stop valve 3.3 respectively; 10) Close the oil inlet on-off valve 2.1 and the oil return on-off valve 2.5 respectively; 11) After checking that the valve position is correct, start the fast-forward hydraulic pump 3.6 to quickly retract the reducing piston 1.2 until it is pushed to the left end and stops.

[0045] Example 4 like Figure 1 and 6As shown, the difference between this embodiment and embodiment 1 lies in that an oil inlet pressure sensor 3.1 and a safety overflow valve 3.2 are provided in the pipeline between the fast-forward stop valve 3.3 of the fast propulsion system 3 and the oil outlet of the small-diameter cylinder 1.4, a visible exhaust device 2.7 is provided between the return oil on-off valve 2.5 of the working system 2 and the hydraulic oil tank 5.1, a return oil pressure sensor 2.4 is provided in the pipeline between the oil outlet of the working cylinder 2.3 of the working system 2 and the return oil on-off valve 2.5, a return oil speed regulating valve 2.6 is provided in the pipeline between the return oil on-off valve 2.5 and the hydraulic oil tank 5.1, and the remaining structures are the same as those in embodiment 1.

[0046] In this embodiment, the working system 2 and the hydraulic pipeline 5.2 can be ensured to be safe from overpressure by adjusting the overflow value of the safety overflow valve 3.2; the visual exhaust device 2.7 can observe the bubbles in the return oil through its glass window to determine whether air has entered and discharge the gas in the working fluid cylinder 2.3, and the return oil flow rate can be controlled by operating the return oil speed regulating valve 2.6 to prevent the return oil containing high-pressure gas from being quickly ejected from the exhaust port of the visual exhaust device 2.7.

[0047] In this embodiment, when the working fluid cylinder is used for the first time, has not been used for a long time, or when there is other oil return through the visual exhaust device, the system should be circulated and exhausted by observing the exhaust device window to determine if there are bubbles in the oil return.

[0048] The circulating exhaust state of the hydraulic feed device is controlled by the following steps: 1) When the working fluid cylinder 2.3 is used for the first time, has not been used for a long time, or is otherwise judged to contain bubbles, it should be circulated and exhausted; 2) Turn on the power supply of the device and adjust the slow-advance reversing valve 4.2 to the middle position; 3) Open the fast-feed pump on-off valve 3.7, the fast-feed stop valve 3.3, the oil inlet on-off valve 2.1, and the oil return on-off valve 2.5 respectively; 4) After checking that the valve position is correct, start the fast-forward hydraulic pump 3.6 to start circulating exhaust; 5) During the cycle, pay attention to the oil return status displayed on the glass window 2.7 of the visual exhaust device; 6) Stop exhausting after observing that there are no bubbles in the glass window 2.7 of the visual exhaust device; 7) After standing for 30 minutes, circulate the exhaust again according to the above steps until there are no bubbles in the return oil.

[0049] It is to be understood that the present invention is described by some embodiments, and it is known to those skilled in the art that various changes or equivalent substitutions may be made to these features and embodiments without departing from the spirit and scope of the present invention. In addition, under the teachings of the present invention, these features and embodiments may be modified to adapt to specific circumstances and materials without departing from the spirit and scope of the present invention. Therefore, the present invention is not limited by the specific embodiments disclosed herein, and all embodiments falling within the scope of the claims of this application are within the scope of protection of the present invention.

Claims

1. A hydraulic feeding device, characterized in that: include, A variable diameter hydraulic cylinder (1), the variable diameter hydraulic cylinder (1) comprising a large diameter hydraulic cylinder (1.1), a variable diameter piston (1.2) and a small diameter hydraulic cylinder (1.4); the large diameter hydraulic cylinder (1.1) and the small diameter hydraulic cylinder (1.4) are coaxially arranged opposite to each other; the variable diameter piston (1.2) comprises a piston rod in the middle and piston heads at two ends respectively matched with the large diameter hydraulic cylinder (1.1) and the small diameter hydraulic cylinder (1.4); the piston heads are respectively arranged in the large diameter hydraulic cylinder (1.1) and the small diameter hydraulic cylinder (1.4); the variable diameter piston (1.2) is pushed by supplying liquid to the large diameter hydraulic cylinder (1.1); and the variable diameter piston (1.2) then pushes the small diameter hydraulic cylinder (1.4); A working system (2), the working system (2) comprising an oil inlet on-off valve (2.1), a working fluid cylinder (2.3) and an oil return on-off valve (2.5), the oil inlet on-off valve (2.1) being connected to an oil outlet of a small-diameter fluid cylinder (1.4) via one end of a hydraulic pipeline (5.2), the other end of the oil on-off valve (2.1) being connected to an oil inlet of the working fluid cylinder (2.3), and the oil outlet of the working fluid cylinder (2.3) being connected to the oil return on-off valve (2.5); A fast-forwarding system (3), the fast-forwarding system (3) comprising a fast-forwarding stop valve (3.3), a fast-forwarding hydraulic pump (3.6) and a fast-forwarding pump on-off valve (3.7), the oil outlet of the fast-forwarding hydraulic pump (3.6), the fast-forwarding pump on-off valve (3.7), the fast-forwarding stop valve (3.3) and the oil outlet of the small-diameter hydraulic cylinder (1.4) are connected in sequence via a hydraulic pipeline (5.2), a tee is installed on the hydraulic pipeline (5.2) between the fast-forwarding pump on-off valve (3.7) and the fast-forwarding stop valve (3.3), and the tee is connected to the oil outlet of the large-diameter hydraulic cylinder (1.1) via the hydraulic pipeline (5.2); A slow propulsion system (4), the slow propulsion system (4) comprising a slow hydraulic pump (4.1) and a slow reversing valve (4.2), the oil outlet of the slow hydraulic pump (4.1) and the slow reversing valve (4.2) being connected via a hydraulic pipeline (5.2), the outlet pipeline of the slow reversing valve (4.2) being respectively connected to the oil inlet and the oil outlet of the large-diameter hydraulic cylinder (1.1), and the power source of the slow hydraulic pump (4.1) being a variable frequency motor; An auxiliary system (5), the auxiliary system (5) comprising a hydraulic oil tank (5.1), the hydraulic oil tank (5.1) being connected to a slow-advance reversing valve (4.2), a slow-advance hydraulic pump (4.1), a fast-advance hydraulic pump (3.6), a fast-advance stop valve (3.3) and an oil return on-off valve (2.5) through hydraulic pipelines (5.2).

2. The hydraulic feeding device according to claim 1, characterized in that: The variable diameter hydraulic cylinder (1) is further provided with a displacement scale (1.3) for real-time monitoring of the position of the variable diameter piston (1.2); the displacement scale (1.3) is arranged at an end position of the large diameter hydraulic cylinder (1.1) near the variable diameter piston (1.2).

3. The hydraulic feeding device according to claim 1, characterized in that: A one-way valve (2.2) is provided on the pipeline between the oil inlet on-off valve (2.1) and the working fluid cylinder (2.3) of the working system (2).

4. The hydraulic feeding device according to claim 1, characterized in that: A visible exhaust device (2.7) is provided between the oil return on-off valve (2.5) of the working system (2) and the hydraulic oil tank (5.1).

5. The hydraulic feeding device according to claim 1, characterized in that: An oil return pressure sensor (2.4) is provided in the pipeline between the oil outlet of the working cylinder (2.3) of the working system (2) and the oil return on-off valve (2.5), and an oil return speed regulating valve (2.6) is provided in the pipeline between the oil return on-off valve (2.5) and the hydraulic oil tank (5.1).

6. The hydraulic feeding device according to claim 1, characterized in that: A fast-forward pressure gauge (3.4) and a fast-forward overflow valve (3.5) are installed in the pipeline between the oil outlet of the fast-forward hydraulic pump (3.6) of the fast-forward system (3) and the hydraulic oil tank (5.1).

7. The hydraulic feeding device according to claim 1, characterized in that: An oil inlet pressure sensor (3.1) and a safety overflow valve (3.2) are provided in the pipeline between the fast-forward stop valve (3.3) of the fast-forward system (3) and the oil outlet of the small-diameter hydraulic cylinder (1.4).

8. The hydraulic feeding device according to claim 1, characterized in that: The oil outlet of the slow-advance hydraulic pump (4.1) is equipped with a slow-advance pressure gauge (4.4) and a slow-advance overflow valve (4.3).

9. A control method for a hydraulic feed device according to any one of claims 1 to 8, comprising the following four working states, namely a slow advancing state, a fast advancing state, a fast retracting state of the variable diameter piston (1.2) and a slow retracting state of the variable diameter piston (1.2); The slow propulsion state control steps are as follows: 1) Turn on the power of the device; 2) Adjust the slow-advance reversing valve (4.2) to the push cylinder position; 3) Open the oil inlet on-off valve (2.1); 4) Close the fast-feed pump on-off valve (3.7), fast-feed stop valve (3.3), and return oil on-off valve (2.5) respectively; 5) After checking that the valve position is correct, start the slow-feed hydraulic pump (4.1) to slowly advance the working hydraulic cylinder (2.3); 6) Further fine-tune the propulsion speed in the slow propulsion state by adjusting the frequency of the variable frequency motor supporting the slow-feed hydraulic pump (4.1); The control steps in the fast advancement state are as follows: 1) Turn on the power of the device; 2) Adjust the slow-advance reversing valve (4.2) to the middle position; 3) Open the fast-feed pump on-off valve (3.7), the fast-feed stop valve (3.3), and the oil inlet on-off valve (2.1) respectively; 4) Close the oil return on-off valve (2.5); 5) After checking that the valve position is correct, turn on the fast-forward hydraulic pump (3.6) to start rapidly advancing the working hydraulic cylinder (2.3); The control steps for the rapid return of the variable diameter piston (1.2) are as follows: 1) When the reducing piston (1.2) in the reducing cylinder (1) moves to the right end, its travel is complete and the reducing piston (1.2) needs to be returned to the left end to advance again; 2) Turn on the power supply of the device and adjust the slow-advance reversing valve (4.2) to the middle position; 3) Open the fast-feed pump on-off valve (3.7) and the fast-feed stop valve (3.3) respectively; 4) Close the oil inlet on-off valve (2.1) and the oil return on-off valve (2.5) respectively; 5) After checking that the valve position is correct, start the fast-forward hydraulic pump (3.6) to quickly retract the reducing piston (1.2) until it is pushed to the left and stops; The control steps when the variable-diameter piston (1.2) is slowly retracted are as follows: 1) When the reducing piston (1.2) in the reducing cylinder (1) moves to the right end, the cylinder begins to be withdrawn; 2) Turn on the power supply of the device and adjust the slow-advance reversing valve (4.2) to the retracted position; 3) Open the fast-forward stop valve (3.3); 4) Close the oil inlet on-off valve (2.1), the oil return on-off valve (2.5), and the fast feed pump on-off valve (3.7) respectively; 5) After checking that the valve position is correct, start the slow-feed hydraulic pump (4.1) and slowly retract the reducing piston (1.2) until it is pushed to the left and stops.

10. The control method according to claim 9, characterized in that: The control method also includes circulating the exhaust state, The control steps in the cycle exhaust state are as follows: 1) When the working fluid cylinder (2.3) is used for the first time, has not been used for a long time, or is otherwise judged to contain bubbles, it should be circulated and exhausted; 2) Turn on the power supply of the device and adjust the slow-advance reversing valve (4.2) to the middle position; 3) Open the fast-feed pump on-off valve (3.7), the fast-feed stop valve (3.3), the oil inlet on-off valve (2.1), and the oil return on-off valve (2.5) respectively; 4) After checking that the valve position is correct, start the fast-forward hydraulic pump (3.6) to start circulating exhaust; 5) During the cycle, pay attention to the oil return status displayed on the glass window of the visual exhaust device (2.7); 6) Stop exhausting after observing that there are no bubbles in the glass window of the visual exhaust device (2.7); 7) After standing for 30 minutes, circulate the exhaust again according to the above steps until there are no bubbles in the return oil.

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