Single-cylinder bolt retraction system and control method

Abstract

The application provides a single-cylinder bolt telescopic system and a control method. The system comprises a telescopic oil cylinder. The driving end comprises a first accumulator, the first accumulator is connected to a P port of a cylinder arm bolt switching valve and a first oil port of a sequence valve through a first connecting oil path, an A port of the cylinder arm bolt switching valve is connected to a second oil port of the sequence valve, a first control end of the sequence valve is connected to a third accumulator, a second control end of the sequence valve is connected to an oil path between the second oil port and the A port of the cylinder arm bolt switching valve, a third oil port of the sequence valve is connected to a rodless cavity of an arm bolt oil cylinder, the first accumulator is connected to a T port of the cylinder arm bolt switching valve through a second connecting oil path, a B port of the cylinder arm bolt switching valve is connected to a rodless cavity of a cylinder bolt oil cylinder, and a liquid storage oil cylinder is connected to a second accumulator and a rod cavity of the telescopic oil cylinder. The hydraulic oil path for driving the cylinder arm bolt mechanism to act is independent of the action of the telescopic oil cylinder, and the movable core pipe in the telescopic oil cylinder is cancelled.

Description

Technical Field

[0001] This invention relates to the field of heavy machinery technology, specifically to a single-cylinder pin telescopic system and its control method. Background Technology

[0002] Currently, in the field of construction machinery, the basic form of a single-cylinder pin telescopic system is to use an independent oil supply system to supply oil to the cylinder head through a movable core tube set inside the telescopic cylinder. The cylinder head is then used to remove the cylinder pin and arm pin, the spring returns to its original position, and the pressure in the small chamber of the telescopic cylinder opens the balance valve to achieve the retraction of the telescopic cylinder.

[0003] The cylinder head, located at a specific position within the telescopic cylinder barrel, is a device used to control the connection and separation between the telescopic cylinder and the boom, as well as between different boom sections. It mainly includes a dovetail groove, cylinder pin, and drive cylinder. Boom pins are used for connecting boom sections. Boom pin holes are holes on the boom used to connect boom pins to specific boom sections. Cylinder pins are used to connect the telescopic cylinder to the tail sections of all boom sections except the base boom.

[0004] The automatic telescopic system of a single-cylinder pin-type crane achieves the telescopic boom function through the combined action of the telescopic cylinder, boom pin, and cylinder pin. Specifically, when inserting the boom pin, the boom pin is inserted into the boom pin hole by means of a return spring, locking two adjacent boom sections together; when removing the cylinder pin, the cylinder pin disengages from the cylinder pin hole on the boom, and the telescopic cylinder and boom disengage, enabling telescopic boom extension without a cylinder; when inserting the cylinder pin, the cylinder pin is inserted into the cylinder pin hole on the boom, locking the telescopic cylinder and boom together, enabling telescopic boom extension.

[0005] boom extension process:

[0006] Forward to find the boom position: Pull out the cylinder pin → Locate the boom position → Find the boom position and insert the cylinder pin → Pull out the boom pin → The cylinder extends the boom → (Decelerate and release the boom pin in advance) Insert the boom pin

[0007] Find the boom position backward: Pull out the cylinder pin → retract the cylinder to find the boom position → find the boom position and insert the cylinder pin → pull out the boom pin → extend the boom with the cylinder → (decelerate and release the boom pin in advance) insert the boom pin

[0008] Crane boom retraction process:

[0009] Retracting the non-current arm: Pull out the cylinder pin → Locate the arm position → Insert the cylinder pin → Pull out the arm pin → Retract the arm → Insert the arm pin. Retracting the current arm: Pull out the arm pin → Retract the arm → Insert the arm pin.

[0010] like Figure 1The diagram shows the hydraulic principle of a single-cylinder pin-type telescopic system for cranes in related technologies. The extension and retraction of the telescopic hydraulic cylinder 14 are controlled by a first variable hydraulic pump 11 in conjunction with a three-position four-way directional valve 12. Specifically, the high-pressure hydraulic fluid output from the first variable hydraulic pump 11 is fed into the rod-side or rodless-side chamber of the telescopic hydraulic cylinder 14 through the control of the three-position four-way electro-proportional directional valve 12 and the first balance valve 13, thereby controlling the extension and retraction of the cylinder. During operation, the current output from the controller to the first variable hydraulic pump 11 is adjusted to control the pump's displacement, which in turn controls the movement speed of the telescopic hydraulic cylinder 14. The direction of the hydraulic fluid is changed by switching the three-position four-way solenoid valve 12, thus switching between the extension and retraction actions of the telescopic hydraulic cylinder 14. The actions of removing the cylinder pin and arm pin are completed by another hydraulic system. The oil output from the second fixed-displacement hydraulic pump 112 passes through the two-position four-way solenoid directional valve 113, the core tube 15 inside the telescopic hydraulic cylinder 14, and the first cylinder arm pin switching valve 16, and enters the first cylinder pin cylinder 17 or the first arm pin cylinder 18 to complete the actions of removing the cylinder pin and arm pin. That is, the oil output to the first cylinder pin cylinder 17 or the first arm pin cylinder 18 overcomes the resistance of the first return spring 19 and pushes the cylinder pin removal mechanism 110 or the arm pin removal mechanism 11 to realize the removal of the cylinder pin and arm pin. The first cylinder arm pin switching valve 16 controls the switching between the two actions of removing the cylinder pin and arm pin. The accumulator 115 at the outlet of the second fixed-displacement hydraulic pump 112 is used to reduce the pressure impact when removing the cylinder pin and arm pin. An overflow valve 114 and an overflow valve 116 are provided between the second fixed-displacement hydraulic pump 112 and the telescopic hydraulic cylinder 14.

[0011] The above-mentioned solutions in the related technologies have at least the following disadvantages: (1) The single-cylinder pin telescopic system adopts the industry's common technical route, resulting in large power loss and high fuel consumption. That is, the cylinder arm pin mechanism requires a separate oil supply system, which is driven by the movable core tube inside the telescopic cylinder; when the cylinder telescopics, it is necessary to ensure the flow rate of the movable core tube while ensuring the system pressure, and the continuous high pressure of the system leads to energy loss. (2) The telescopic cylinder has a movable core tube, which has a complex structure and requires high processing precision, resulting in a high price for the telescopic cylinder and making it difficult to further improve its lightweight design. Due to the poor compactness of the telescopic cylinder, the single-cylinder pin telescopic system is difficult to promote and apply in small-tonnage products; small-tonnage products are limited by the width of the arm tail, and the cylinder head cannot be expanded, which also makes it difficult to expand the piston rod, so the movable core tube is difficult to arrange. Summary of the Invention

[0012] This invention provides a single-cylinder pin telescopic system and method to solve the above-mentioned technical problems. The technical solution adopted is as follows:

[0013] A single-cylinder pin telescopic system, comprising:

[0014] Telescopic hydraulic cylinder;

[0015] The driver side includes:

[0016] The first accumulator, after being filled with fluid by the telescopic cylinder, serves as the oil source for the cylinder arm pin unit; the cylinder arm pin unit includes a cylinder arm pin switching valve and a sequence valve.

[0017] The first accumulator is connected to the P port of the cylinder arm pin switching valve and the first port of the sequence valve via a first connecting oil circuit; the A port of the cylinder arm pin switching valve is connected to the second port of the sequence valve; the first control terminal of the sequence valve is connected to the third accumulator, and a third check valve is provided between the third accumulator and the first port; the third check valve is open from the first port to the third accumulator; the second control terminal of the sequence valve is connected to the oil circuit between the second port and the A port of the cylinder arm pin switching valve; the third port of the sequence valve is connected to the rodless chamber of the cylinder arm pin cylinder.

[0018] The first accumulator is connected to the T port of the cylinder arm pin switching valve through the second connecting oil circuit, and a fifth check valve is provided on the second connecting oil circuit; the fifth check valve is open from the T port of the cylinder arm pin switching valve toward the first accumulator; the B port of the cylinder arm pin switching valve is connected to the rodless chamber of the cylinder pin cylinder.

[0019] A reservoir cylinder has its rodless chamber connected to a second accumulator and the rod chamber of a telescopic cylinder. A first check valve is installed on a third connecting oil line between the rodless chamber of the reservoir cylinder and the rod chamber of the telescopic cylinder. The third connecting oil line is connected to a second connecting oil line, with its connection point located between a second overflow valve and a fifth check valve. A fourth check valve is installed between the third connecting oil line and the first connecting oil line. The first check valve opens from the connection point toward the telescopic cylinder, and the fourth check valve opens from the telescopic cylinder toward the third connecting oil line.

[0020] Preferably, it further includes: a two-position four-way valve, whose P port is connected to the first connecting oil circuit, its T port is connected to the second connecting oil circuit, and its B port is connected to the rodless chamber of the liquid storage cylinder; when energized, the P port is connected to the B port, and when de-energized, the P port is connected to the A port.

[0021] Preferably, it further includes an oil supply end, which includes an oil tank, a hydraulically controlled proportional directional valve, and a first relief valve. The rod-side chamber of the telescopic cylinder is connected to the oil tank through the first relief valve, and the rodless chamber of the telescopic cylinder is connected to the oil tank through one passage of the hydraulically controlled proportional directional valve. The other passage of the hydraulically controlled proportional directional valve is connected in parallel with the first relief valve. The two control ends of the hydraulically controlled proportional directional valve are respectively connected to an electro-proportional pressure reducing valve, which is respectively connected to the pilot oil and the oil tank.

[0022] Preferably, the oil supply end further includes a balance valve, the rodless chamber of the telescopic cylinder is connected to the hydraulic proportional directional valve through the balance valve, and the control end of the balance valve is connected to the rod chamber of the telescopic cylinder.

[0023] Preferably, the arm pin cylinder and the cylinder pin cylinder are respectively connected to the arm pin mechanism and the cylinder pin mechanism, and the arm pin and cylinder pin are pulled out by the oil inlet and outlet of the rod-side chamber and the rodless chamber of the arm pin cylinder and the cylinder pin cylinder.

[0024] Preferably, when the hydraulically controlled proportional directional valve is in the first interval, the oil circuit between port P and port B, and between port A and port T is cut off; when the hydraulically controlled proportional directional valve is in the second interval, the proportional valve core is connected to port P and port B, and between port A and port T.

[0025] Preferably, a second relief valve is also provided on the second connecting oil line, and the second relief valve is connected in parallel with a second check valve; the fifth check valve is located near the cylinder arm pin switching valve; the flow direction of the second check valve is from the T port of the cylinder arm pin switching valve to the first accumulator.

[0026] A control method for a single-cylinder pin telescopic system includes:

[0027] Normal operation of the pull arm pin:

[0028] Control the telescopic cylinder to perform the retraction action, and charge the high-pressure oil in the rod chamber of the telescopic cylinder into the first accumulator through the fourth check valve and the first connecting oil circuit;

[0029] When the cylinder arm pin switching valve Y1 is energized, the P port and A port of the cylinder arm pin switching valve are connected. The high-pressure oil from the first accumulator passes through the cylinder arm pin switching valve and the sequence valve to reach the rodless chamber of the arm pin cylinder, driving the arm pin cylinder to move and realize the arm pin pulling operation.

[0030] Normal cylinder pin removal procedure:

[0031] Control the telescopic cylinder to perform the retraction action, and charge the high-pressure oil in the rod chamber of the telescopic cylinder into the first accumulator through the fourth check valve and the first connecting oil circuit;

[0032] When cylinder arm pin switching valve Y2 is energized, the P port and B port of the cylinder arm pin switching valve are connected. The high-pressure oil from the first accumulator reaches the rodless chamber of the cylinder pin cylinder through the cylinder arm pin switching valve, driving the cylinder pin cylinder to perform the cylinder pin pulling operation.

[0033] Emergency pull-out pin operation:

[0034] Adjust the overflow pressure of the first relief valve so that the oil pressure in both the first and third accumulators is greater than the reversing set pressure of the sequence valve.

[0035] Control the telescopic cylinder to perform the retraction action, and charge the high-pressure oil in the rod chamber of the telescopic cylinder into the first accumulator, so that the oil pressure in both the first and third accumulators is greater than the reversing set pressure of the sequence valve.

[0036] High-pressure oil in the first accumulator reaches the rodless chamber of the arm pin cylinder through a sequence valve, driving the arm pin cylinder to perform an emergency arm pin release operation.

[0037] Preferably, controlling the telescopic cylinder to perform the retraction action includes: controlling the hydraulic proportional directional valve by adjusting the input current of the electro-proportional pressure reducing valve, and controlling the telescopic cylinder to perform the retraction action by the action of the hydraulic proportional directional valve.

[0038] Compared with the prior art, the advantages of the present invention are:

[0039] (1) When the drive cylinder arm pin moves, the oil is no longer supplied through the movable core tube inside the telescopic cylinder, but an independent hydraulic pipeline is used; the hydraulic oil circuit that drives the cylinder arm pin mechanism is independent of the movement of the telescopic cylinder.

[0040] (2) The hydraulic proportional directional valve of the main system is designed with an integrated approach. Different telescoping states (accumulator filling, reverse and plugging / unplugging cylinder arm pins, acceleration / deceleration, maximum speed, etc.) have different principles.

[0041] (3) This system eliminates the movable core tube inside the telescopic cylinder, simplifies the structure of the telescopic cylinder, reduces the processing difficulty and weight, and reduces the system cost; it also reduces the system maintenance difficulty and cost, reduces the processing difficulty and weight of the cylinder, and overcomes the difficulty of "the movable core tube restricting the inner diameter of the telescopic cylinder piston rod", so that the single-cylinder pin system can be promoted to small and medium tonnage products.

[0042] (4) Eliminate the separate cylinder arm pin oil supply system and use a high-pressure accumulator to remove the cylinder arm pin.

[0043] (5) A liquid storage cylinder and / or a low-pressure accumulator are used to quickly absorb the oil released from the high-pressure chamber of the cylinder arm pin cylinder, thereby improving the release responsiveness and reliability of the cylinder arm pin.

[0044] (6) Using a separate accumulator to supply oil to the sequence valve switching can better maintain the emergency pull arm pin. Attached Figure Description

[0045] Figure 1 This is a hydraulic schematic diagram of a telescopic system in the prior art;

[0046] Figure 2 This is a schematic diagram of the single-cylinder pin telescopic system of the present invention;

[0047] Figure 3 Schematic diagrams of hydraulically controlled proportional directional valves in different current ranges;

[0048] Figure 4 Flowchart of the liquid filling control for the first accumulator;

[0049] Figure 5This is a curve showing the change in the flow area of ​​the valve orifice as a function of the valve core displacement.

[0050] Among them, 11-first variable hydraulic pump; 12-three-position four-way directional valve; 13-first balance valve; 14-telescopic hydraulic cylinder; 15-core tube; 16-first cylinder arm pin switching valve; 17-first arm pin cylinder; 18-first cylinder pin cylinder; 19-first return spring; 110-cylinder pin release mechanism; 111-arm pin release mechanism; 112-second quantitative hydraulic pump; 113-two-position four-way solenoid directional valve; 114-relief valve one; 115-accumulator; 116-relief valve two; 21-first relief valve; 22-variable hydraulic pump ; 23-Electro-proportional pressure reducing valve; 24-Hydraulic proportional directional valve; 25-Balance valve; 26-Telescopic cylinder; 27-First accumulator; 28-First check valve; 29-Second relief valve; 210-Second check valve; 211-Second accumulator; 212-Cylinder pin cylinder; 213-Arm pin cylinder; 214-Sequence valve; 215-Third accumulator; 216-Third check valve; 217-Cylinder arm pin switching valve; 218-Fourth check valve; 219-Fifth check valve; 220-Two-position four-way valve; 221-Reservoir cylinder. Implementation

[0051] The present invention will now be described in more detail with reference to the accompanying drawings, which illustrate preferred embodiments of the invention. It should be understood that those skilled in the art can modify the invention described herein while still achieving its advantageous effects. Therefore, the following description should be understood as being of general knowledge to those skilled in the art and is not intended to limit the invention.

[0052] like Figures 2-5 As shown, a single-cylinder pin telescopic system includes: a telescopic cylinder 26, a drive end, and a power supply end.

[0053] Telescopic cylinder 26 is used to drive the telescopic boom of the crane to extend or retract. There is no movable core tube inside the telescopic cylinder 26.

[0054] The driver side includes:

[0055] The first accumulator 27, after being filled with liquid by the telescopic cylinder 26, serves as the oil source for the cylinder arm pin unit; the cylinder arm pin unit includes a cylinder arm pin switching valve 217 and a sequence valve 214.

[0056] The first accumulator 27 is connected to the P port of the cylinder arm pin switching valve 217 and the first oil port of the sequence valve 214 via the first connecting oil circuit; the A port of the cylinder arm pin switching valve 217 is connected to the second oil port of the sequence valve 214; the first control end of the sequence valve 214 is connected to the third accumulator 215, and a third check valve 216 is provided between the third accumulator 215 and the first oil port; the third check valve 216 is open from the first oil port to the third accumulator 215; the second control end of the sequence valve 214 is connected to the oil circuit between the second oil port and the A port of the cylinder arm pin switching valve 217; the third oil port of the sequence valve 214 is connected to the rodless chamber of the cylinder arm pin cylinder 213.

[0057] The first accumulator 27 is connected to the T port of the cylinder arm pin switching valve 217 via a second connecting oil circuit. A fifth check valve 219 is installed on the second connecting oil circuit. The fifth check valve 219 is open from the T port of the cylinder arm pin switching valve 217 toward the first accumulator 27. The B port of the cylinder arm pin switching valve 217 is connected to the rodless chamber of the cylinder pin cylinder 212. A second relief valve 29 is also installed on the second connecting oil circuit. The second relief valve 29 is connected in parallel with the second check valve 210. The fifth check valve 219 is located close to the cylinder arm pin switching valve 217. The flow direction of the second check valve 210 is from the T port of the cylinder arm pin switching valve 217 toward the first accumulator 27.

[0058] As can be seen from the prior art, the arm pin cylinder 213 and the cylinder pin cylinder 212 are respectively connected to the arm pin mechanism and the cylinder pin mechanism. The arm pin and the cylinder pin are pulled out by the oil inlet and outlet of the rod chamber and the rodless chamber of the arm pin cylinder 213 and the cylinder pin cylinder 212.

[0059] The reservoir cylinder 221 has its rodless chamber connected to the rod chamber of the second accumulator 211 and the telescopic cylinder 26. A first check valve 28 is installed on the third connecting oil line between the rodless chamber of the reservoir cylinder 221 and the rod chamber of the telescopic cylinder 26. The third connecting oil line is connected to the second connecting oil line, and its connection point is located between the second overflow valve 29 and the fifth check valve 219. A fourth check valve 218 is installed between the third connecting oil line and the first connecting oil line. The first check valve 28 is open from the connection point toward the telescopic cylinder 26, and the fourth check valve 218 is open from the telescopic cylinder 26 toward the third connecting oil line.

[0060] The two-position four-way valve 220 has its P port connected to the first connecting oil circuit, its T port connected to the second connecting oil circuit, and its B port connected to the rodless chamber of the reservoir cylinder 221. When energized, the P port is connected to the B port; when de-energized, the P port is connected to the A port. During the extension of the telescopic cylinder 26, the Y3 valve of the two-position four-way valve 220 is energized, and the high-pressure oil in the first accumulator 27 flows into the first connecting oil circuit, enters the B port of the two-position four-way valve 220 through the P port, and then enters the rod chamber of the reservoir cylinder 221 through the B port, causing the piston rod to retract. When the pressure in the first accumulator 27 exceeds a certain value, it overflows through the second relief valve 29.

[0061] After running for a period of time, as the return oil is continuously discharged into the rod chamber of the telescopic cylinder 26, the pressure in the rod chamber of the telescopic cylinder 26 continuously increases. When it increases to a certain set value, the return oil in the second accumulator 211 or / and the storage cylinder 221 can no longer be discharged to the telescopic cylinder 26. At this time, the two-position four-way valve 220 is energized, and the P port is connected to the B port. The return oil in the rod chamber of the storage cylinder 221 continuously increases, and the return oil in its rodless chamber can be discharged to the rod chamber of the telescopic cylinder 26.

[0062] The oil supply end includes an oil tank, a variable displacement hydraulic pump 22, a hydraulically controlled proportional directional valve 24, and a first relief valve 21. The rod chamber of the telescopic cylinder 26 is connected to the oil tank through the first relief valve 21, and the rodless chamber of the telescopic cylinder 26 is connected to the oil tank through one passage of the hydraulically controlled proportional directional valve 24. The other passage of the hydraulically controlled proportional directional valve 24 is connected in parallel with the first relief valve 21. The two control terminals of the hydraulically controlled proportional directional valve 24 are respectively connected to an electro-proportional pressure reducing valve 23, which is connected to the pilot oil and the oil tank respectively. The oil supply end also includes a balance valve 25. The rodless chamber of the telescopic cylinder 26 is connected to the hydraulically controlled proportional directional valve 24 through the balance valve 25, and the control terminal of the balance valve 25 is connected to the rod chamber of the telescopic cylinder 26. Controlling the telescopic cylinder 26 to perform the retraction action includes: controlling the hydraulically controlled proportional directional valve 24 by adjusting the input current of the electro-proportional pressure reducing valve 23, and controlling the telescopic cylinder 26 to perform the retraction action by the action of the hydraulically controlled proportional directional valve 24.

[0063] The hydraulic schematic diagram of the single-cylinder pin telescopic system is as follows: Figure 2 As shown, the extension and retraction of the telescopic cylinder 26 are controlled by a hydraulically controlled proportional directional valve 24. Two electro-proportional pressure reducing valves 23 respectively control the pressure of the control oil at both ends of the valve stem of the hydraulically controlled proportional directional valve 24. Therefore, the movement of the valve stem of the hydraulically controlled proportional directional valve 24 can be controlled by adjusting the input current of the electro-proportional pressure reducing valve 24; that is, the valve stem displacement of the hydraulically controlled proportional directional valve is related to the magnitude of the input current of the electro-proportional pressure reducing valve. Therefore, the requirements of the telescopic hydraulic system characteristics under different working conditions and sub-states of the telescopic system can be met by adjusting the current output of the controller to the electro-proportional pressure reducing valve.

[0064] The hydraulic proportional directional valve 24 of the main system is designed using an integrated approach. The boom extension and retraction utilize the same valve stem. The displacement of the proportional directional valve stem is approximately proportional to the input current of the electro-proportional pressure reducing valve. The flow area of ​​the directional valve stem varies piecewise with the valve core displacement (current), rather than linearly. For example... Figure 3 As shown, the corresponding telescopic main system principle is different in different telescopic states. Typical telescopic states such as accumulator filling, inverted and plugged cylinder arm pins, and maximum speed correspond to the first, second, and third sections of the electro-proportional valve (from left to right: first section, second section, and third section).

[0065] The first section is used when the first accumulator is filled with liquid. The inlet flow area of ​​the hydraulically controlled proportional directional valve 24 is a constant value, and the return flow area is zero. The second section of the proportional directional valve is used for sub-states such as backing and inserting / removing cylinder arm pins. Both the inlet and return flow areas are constant values. When the crane is in the above states of extension and retraction, the displacement of the proportional directional valve only needs to be within a certain range to meet the requirements. When the crane's performance drifts during factory testing or after a period of use, there is no need to repeatedly adjust the controller output current, reducing control difficulty. The latter half of the second section of the proportional directional valve is used for acceleration and deceleration sub-states, where the inlet and return flow areas change proportionally with the displacement of the proportional directional valve. The third section of the proportional directional valve is used for the maximum extension / retraction speed state.

[0066] (1) The first section of the hydraulic proportional directional valve 24 is mainly used to enable the hydraulic pump to quickly charge the first accumulator when the crane is stationary for a long time or when the boom is extended outward and the accumulator pressure is too low to complete the removal of the cylinder boom pin. In the first section of the proportional valve, the proportional directional valve core connects port P and port B, and the oil circuit between port A and port T is cut off. The flow area of ​​the throttling port between port P and port B is a constant value.

[0067] The pump output oil flows through the proportional directional valve throttle orifice to the small chamber of the telescopic cylinder, blocking the oil return path in the large chamber of the telescopic cylinder, and the pump charges the first accumulator. To improve the accumulator charging efficiency, the flow area of ​​the throttle orifice corresponding to this section is generally larger than the flow area in the reverse-locked, cylinder pin-pulling, and arm-retracted starting states. Its basic control flowchart is as follows: Figure 4 As shown.

[0068] (2) When the hydraulic proportional directional valve is in the second zone, the proportional valve core connects port P and port B, port A and port T. The hydraulic pump output oil flows into the small chamber of the telescopic cylinder through the proportional valve, and the oil in the telescopic cylinder returns through the proportional valve.

[0069] When the crane is in the inverted position of the telescopic cylinder, when the cylinder pin is being pulled out, and when the boom is retracted and started, the telescopic cylinder needs to move slowly and smoothly. At this time, the throttling area of ​​the proportional valve inlet and outlet throttling groove is also fixed. At this time, the flow area of ​​the proportional valve return port throttling groove is small, and the telescopic cylinder is almost in constant speed.

[0070] When the crane's telescopic system is in the acceleration or deceleration motion state, the proportional valve's P port is connected to the B port, and its A port is connected to the T port. The flow area of ​​the proportional valve's oil outlet and return throttling ports increases with the increase of the input current.

[0071] (3) When the proportional directional valve is in the third zone, the controller output current reaches its maximum value, and the oil outlet and return ports of the proportional valve are also at their maximum. At this time, the flow rate of the telescopic system is at its maximum, and the telescopic cylinder moves at its maximum speed.

[0072] For example: The stem displacement of a hydraulic proportional valve is approximately proportional to the input current of an electro-proportional pressure reducing valve. Taking a certain telescopic system as an example, the flow area of ​​the directional valve stem changes in segments with the valve core displacement (current), and the flow area of ​​the valve port changes with the magnitude of the valve core displacement (current) as follows: Figure 5 As shown. The first interval is when the displacement of the proportional directional valve is within the range of ab; the second interval is when the displacement of the proportional directional valve is within the range of bd, where the bc interval is used for sub-states such as reverse turning, cylinder pin insertion / removal, and starting with arm retraction, and the cd interval is used for motion sub-states such as acceleration and deceleration; the third interval is when the displacement of the proportional directional valve is greater than d.

[0073] A control method for a single-cylinder pin telescopic system includes:

[0074] When the telescopic cylinder 26 retracts, the high-pressure oil in the small chamber (rod chamber) of the cylinder fills the first accumulator 27. The accumulator, once filled, serves as the oil source for the cylinder arm pin system.

[0075] The cylinder pin switching valve 217 can extend and retract the cylinder pin cylinder 212 and the arm pin cylinder 213, thereby realizing the switching of cylinder pin pulling and arm pin pulling actions.

[0076] (1) Normal operation of the pull arm pin.

[0077] The telescopic cylinder 26 is controlled to perform a retraction action, and the high-pressure oil in the rod chamber of the telescopic cylinder 26 is charged into the first accumulator 27 through the fourth one-way valve 218 and the first connecting oil circuit.

[0078] When the cylinder arm pin switching valve 217Y1 is energized and operates in the left position, the P port and A port of the cylinder arm pin switching valve 217 are connected. The high-pressure oil from the first accumulator 27 passes through the cylinder arm pin switching valve 217 and the sequence valve 214 to reach the rodless chamber of the arm pin cylinder 213, driving the arm pin cylinder 213 to actuate and realize the arm pin release operation. That is, the cylinder barrel of the arm pin cylinder 213 is fixed, and the piston rod of the cylinder drives the arm pin release mechanism to actuate under the action of oil pressure, thereby realizing the release of the arm pin.

[0079] When Y1 loses power, the oil in the rodless chamber of the arm pin cylinder 213 flows back to the second accumulator 211 and / or the reservoir cylinder 221 under the action of the spring (existing technology). Specifically, the oil flows through the third port and the second port of the sequence valve, the A port and the T port of the arm pin switching valve 217, into the fifth check valve 219 of the second connecting oil circuit, and then flows back to the second accumulator 211 and / or the reservoir cylinder 221 through the connection point on the third connecting oil circuit. The return oil from the second accumulator 211 and the reservoir cylinder 221 finally flows back to the rod chamber of the telescopic cylinder 26 through the first check valve 28.

[0080] (2) Normal cylinder pin removal operation.

[0081] The telescopic cylinder 26 is controlled to perform a retraction action, and the high-pressure oil in the rod chamber of the telescopic cylinder 26 is charged into the first accumulator 27 through the fourth one-way valve 218 and the first connecting oil circuit.

[0082] When the cylinder arm pin switching valve 217Y2 is energized and operates in the right position, the P and B ports of the cylinder arm pin switching valve 217 are connected. The high-pressure oil from the first accumulator 27 passes through the cylinder arm pin switching valve 217 to the rodless chamber of the cylinder pin cylinder 212, driving the cylinder pin cylinder 212 to perform the cylinder pin removal operation. That is, the cylinder barrel of the cylinder pin cylinder 212 is fixed, and the piston rod of the cylinder, under the action of oil pressure, drives the cylinder pin removal mechanism to perform the cylinder pin removal action. The oil in the rodless chamber of the cylinder pin cylinder 212 returns to the low-pressure chamber (rod chamber) of the telescopic cylinder through the one-way valve assembly.

[0083] When Y2 loses power, the oil in the rodless chamber of the cylinder pin cylinder 212 flows back to the second accumulator 211 and / or the reservoir cylinder 221 under the action of the spring (existing technology). Specifically, the oil flows through the B port and T port of the cylinder arm pin switching valve 217 into the fifth check valve 219 of the second connecting oil circuit, and then flows back to the second accumulator 211 and / or the reservoir cylinder 221 through the connection point on the third connecting oil circuit. The return oil from the second accumulator 211 and the reservoir cylinder 221 finally flows back to the rod chamber of the telescopic cylinder 26 through the first check valve 28.

[0084] (3) Emergency pull-out pin operation.

[0085] Figure 2 In the middle, the sequence valve 214 is in the forward switching state, and the sequence valve 214 is only required to switch when an emergency arm needs to be pulled out.

[0086] Adjust the overflow pressure of the first relief valve 21 to make it greater than a certain pressure value. First, control the hydraulic proportional directional valve to be in the first micro-motion zone, so that the oil pressure of the first accumulator 27 and the third accumulator 215 are both greater than the directional setting pressure of the sequence valve 214.

[0087] The telescopic cylinder 26 is controlled to retract, and the high-pressure oil in the rod chamber of the telescopic cylinder 26 is charged into the first accumulator 27, so that the oil pressure in both the first accumulator 27 and the third accumulator 215 is greater than the reversing set pressure of the sequence valve 214. Therefore, the sequence valve 214 reverses, that is, the first oil port of the sequence valve 214 is connected to the third oil port.

[0088] High-pressure oil in the first accumulator 27 reaches the rodless chamber of the boom pin cylinder 213 through the first and third ports of the sequence valve 214, driving the boom pin cylinder 213 to perform an emergency boom pin retraction operation. Since the boom pin cylinder 213 has a certain volume during emergency boom pin retraction, the pressure in the first accumulator 27 will decrease. To prevent the sequence valve 24 from quickly resetting, the pressure in the third accumulator 215 (containing a large amount of high-pressure oil) is used to maintain the reversal, allowing the boom to retract smoothly.

[0089] In summary, this system improves the stability, energy efficiency, and compactness of telescopic systems while reducing weight, noise, and cost. Specifically:

[0090] (1) A new principle of telescopic main system is provided. By integrating the system, the principle is different in different telescopic sub-states. This form will not lead to an increase in the cost of the main valve. In states such as reverse, plugging and unplugging cylinder arm pin, and starting with arm retraction, the stability of the telescopic system is improved and the noise is reduced. When the crane is factory-tested or when performance drift occurs during long-term use, there is no need to repeatedly adjust the control current, thereby reducing the control difficulty.

[0091] (2) A new cylinder arm pin system principle is provided, which improves energy efficiency. A high-pressure accumulator is used to pull the cylinder arm pin, and a liquid storage cylinder or / and a low-pressure accumulator are used to quickly absorb the oil released from the high-pressure chamber of the cylinder arm pin cylinder, thereby improving the release responsiveness and reliability of the cylinder arm pin.

[0092] (3) The movable core inside the telescopic cylinder is eliminated, which simplifies the structure of the telescopic cylinder, reduces the processing difficulty, and reduces the cost.

[0093] (4) A separate accumulator (third accumulator 215) is used to supply oil to the sequence valve 214 for switching. After the emergency pull-out pin is released, the oil pressure in the main accumulator (first accumulator 27) will drop rapidly, but the pressure in the auxiliary accumulator (third accumulator 215) will drop more slowly, which can better maintain the emergency pull-out pin.

[0094] (5) When the pressure of the first accumulator exceeds the set value, it overflows through the overflow valve; when the pressure of the first accumulator is low, the oil in the return oil circuit can be discharged to the high-pressure accumulator to reduce its charging time.

[0095] The above are merely preferred embodiments of the present invention and do not constitute any limitation on the present invention. Any equivalent substitutions or modifications made by those skilled in the art to the technical solutions and content disclosed in the present invention without departing from the scope of the present invention shall be deemed to have remained within the protection scope of the present invention.

Claims

1. A single cylinder bolt retraction system, characterized by, The utility model relates to a kind of hydraulic cylinder, including: Telescopic oil cylinder, movable core pipe is not arranged in telescopic oil cylinder; Drive end, including: First accumulator, is filled with liquid by telescopic oil cylinder to be used as the oil source of cylinder arm pin unit after completion;The cylinder arm pin unit includes cylinder arm pin switching valve and sequence valve; The first accumulator is connected to the P port of cylinder arm pin switching valve, the first oil port of sequence valve by first connecting oil circuit;The A port of cylinder arm pin switching valve is connected to the second oil port of sequence valve;The first control end of sequence valve is connected to third accumulator, and third one-way valve is arranged between third accumulator and first oil port;The third one-way valve is conducted by first oil port to third accumulator direction;The second control end of sequence valve is connected to the oil circuit between second oil port and the A port of cylinder arm pin switching valve;The third oil port of sequence valve is connected to the rodless chamber of arm pin cylinder; The first accumulator is connected to the T port of cylinder arm pin switching valve by second connecting oil circuit, and fifth one-way valve is arranged on the second connecting oil circuit;The fifth one-way valve is conducted by the T port of cylinder arm pin switching valve to the first accumulator direction;The B port of cylinder arm pin switching valve is connected to the rodless chamber of cylinder pin oil cylinder; Liquid storage oil cylinder, its rodless chamber is connected to the rod chamber of telescopic oil cylinder and second accumulator;First one-way valve is arranged on the third connecting oil circuit between the rodless chamber of liquid storage oil cylinder and the rod chamber of telescopic oil cylinder;Third connecting oil circuit is communicated with second connecting oil circuit, and the communication point is located between second overflow valve and fifth one-way valve;Fourth one-way valve is arranged between third connecting oil circuit and first connecting oil circuit;The first one-way valve is conducted by communication point to telescopic oil cylinder direction, and fourth one-way valve is conducted by telescopic oil cylinder to third connecting oil circuit direction; Further including: two-position four-way valve, its P port is connected to first connecting oil circuit, its T port is connected to second connecting oil circuit, and its B port is connected to the rodless chamber of liquid storage oil cylinder;When being powered, P port is communicated with B port, and when being unpowered, P port is communicated with A port; Further including oil supply end, the oil supply end includes oil tank, hydraulic control proportional reversing valve and first overflow valve, the rod chamber of telescopic oil cylinder is connected to oil tank by first overflow valve, and the rodless chamber of telescopic oil cylinder is connected to oil tank by one passage of hydraulic control proportional reversing valve;The other passage of hydraulic control proportional reversing valve is connected to first overflow valve in parallel, and the control end of hydraulic control proportional reversing valve on both sides is connected to electric proportional pressure reducing valve respectively, and the electric proportional pressure reducing valve is connected to pilot oil and oil tank respectively; When the hydraulic control proportional reversing valve is in the first interval, the hydraulic control proportional reversing valve spool is communicated with P port and B port, and the oil circuit between A port and T port is cut off;When the hydraulic control proportional reversing valve is in the second interval, the hydraulic control proportional reversing valve spool is communicated with P port and B port, and A port and T port, and the hydraulic pump output oil flows into the small chamber of telescopic oil cylinder through the hydraulic control proportional reversing valve, and the telescopic oil cylinder oil flows back through the hydraulic control proportional reversing valve throttle;When the hydraulic control proportional reversing valve is in the third interval, the current output by controller reaches the maximum, and the oil outlet and oil return port of hydraulic control proportional reversing valve are also at the maximum.

2. The single cylinder bolt retraction system of claim 1, wherein, The oil supply end further includes balance valve, and the rodless chamber of telescopic oil cylinder is connected to hydraulic control proportional reversing valve through balance valve, and the control end of balance valve is connected to the rod chamber of telescopic oil cylinder.

3. The single-cylinder bolt retraction system of claim 1, wherein, The arm pin oil cylinder and the cylinder pin oil cylinder are connected with the arm pin mechanism and the cylinder pin mechanism respectively, and the arm pin and the cylinder pin are pulled by the oil inlet and outlet of the rod cavity and the rodless cavity of the arm pin oil cylinder and the cylinder pin oil cylinder.

4. The single-cylinder bolt retraction system of claim 1, wherein, The second overflow valve is arranged on the second connecting oil path, and the second overflow valve is connected with the second check valve in parallel; the fifth check valve is arranged close to the cylinder arm pin switching valve; the flow direction of the second check valve is from the T port of the cylinder arm pin switching valve to the first accumulator.

5. A control method of a single-cylinder bolt retraction system, characterized by, The method comprises the following steps: Normal arm pin pulling operation: Control the telescopic oil cylinder to perform a shrinking action, and fill the high-pressure oil in the rod cavity of the telescopic oil cylinder into the first accumulator through the fourth check valve and the first connecting oil path; The cylinder arm pin switching valve Y1 is electrified, and the left position works, the P port and the A port of the cylinder arm pin switching valve are connected, and the high-pressure oil of the first accumulator reaches the rodless cavity of the arm pin oil cylinder through the cylinder arm pin switching valve and the sequence valve, drives the arm pin oil cylinder to work, and the arm pin pulling operation is realized; When Y1 is de-energized, the oil in the rodless cavity of the arm pin oil cylinder flows back to the second accumulator or / and the liquid storage oil cylinder under the action of the spring; the oil flows into the fifth check valve of the second connecting oil path through the third oil port, the second oil port of the sequence valve, the A port of the cylinder arm pin switching valve and the T port of the cylinder arm pin switching valve, flows back to the second accumulator or / and the liquid storage oil cylinder through the communication point on the third connecting oil path, and the oil back of the second accumulator and the liquid storage oil cylinder finally flows back to the rod cavity of the telescopic oil cylinder through the first check valve; Normal cylinder pin pulling operation: Control the telescopic oil cylinder to perform a shrinking action, and fill the high-pressure oil in the rod cavity of the telescopic oil cylinder into the first accumulator through the fourth check valve and the first connecting oil path; The cylinder arm pin switching valve Y2 is electrified, and the right position works, the P port and the B port of the cylinder arm pin switching valve are connected, and the high-pressure oil of the first accumulator reaches the rodless cavity of the cylinder pin oil cylinder through the cylinder arm pin switching valve, drives the cylinder pin oil cylinder to work, and the cylinder pin pulling operation is realized; When Y2 is de-energized, the oil in the rodless cavity of the cylinder pin oil cylinder flows back to the second accumulator or / and the liquid storage oil cylinder under the action of the spring; the oil flows into the fifth check valve of the second connecting oil path through the B port of the cylinder arm pin switching valve and the T port of the cylinder arm pin switching valve, flows back to the second accumulator or / and the liquid storage oil cylinder through the communication point on the third connecting oil path, and the oil back of the second accumulator and the liquid storage oil cylinder finally flows back to the rod cavity of the telescopic oil cylinder through the first check valve; Emergency arm pin pulling operation: Adjust the overflow pressure of the first overflow valve, so that the oil pressures of the first accumulator and the third accumulator are greater than the switching setting pressure of the sequence valve, Control the telescopic oil cylinder to perform a shrinking action, and fill the high-pressure oil in the rod cavity of the telescopic oil cylinder into the first accumulator, so that the oil pressures of the first accumulator and the third accumulator are greater than the switching setting pressure of the sequence valve, the sequence valve switches, and the first oil port of the sequence valve is connected with the third oil port; The high-pressure oil in the first accumulator reaches the rodless cavity of the arm pin oil cylinder through the first oil port and the third oil port of the sequence valve, drives the arm pin oil cylinder to work, and the emergency arm pin pulling operation is realized; The control of the telescopic oil cylinder to perform a shrinking action comprises: controlling the hydraulic control proportional switching valve by adjusting the input current of the electric proportional pressure reducing valve, and controlling the telescopic oil cylinder to perform a shrinking action by the action of the hydraulic control proportional switching valve.

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