Electric proportional pump pressure cut-off control device and concrete pump truck

Abstract

The present invention discloses an electric proportional pump pressure cut-off control device and a concrete pump truck, and belongs to the field of concrete pump truck pumping hydraulic system. A one-way valve, a pressure cut-off module connected to the two one-way valves, and a shuttle valve connected to the pressure cut-off module are respectively installed at the two-chamber oil ports of the main oil pump variable cylinder. The shuttle valve is used to select the high pressure of the pressure oil at the oil port of the main oil pump, and the pressure is used to act on the pressure cut-off module. When the pressure reaches the set value of the pressure cut-off module, the pressure oil in the main oil pump variable cylinder is unloaded through the pressure cut-off module, and the pressure in the variable cylinder drops, thereby reducing the oil pump displacement and achieving overpressure protection. A one-way valve is respectively set at the two-chamber oil ports of the main oil pump variable cylinder, and a pressure cut-off module is set at the same time. The system pressure is selected by the shuttle valve, and the pressure of the main system is taken to control the unloading valve to open. After the unloading valve is opened, the oil in the main oil pump variable cylinder returns to the oil tank through the unloading valve, so that the main oil pump displacement is reduced.

Description

Technical Field

[0001] The invention relates to the technical field of a concrete pump truck pumping hydraulic system, and in particular to an electric proportional pump pressure cut-off control device and a concrete pump truck. Background Art

[0002] The pumping hydraulic system is the main component of the concrete pump truck, and its reliability directly determines the performance of the entire vehicle. Overpressure protection is a function required by general pumping hydraulic systems and is used to protect the hydraulic system when the system fails.

[0003] However, the existing technology adopts two solutions: one is to set a safety valve, and the system can only be protected by overflowing the safety overflow valve after overpressure. In this case, the system will generate a lot of heat; the other is to use electrical program control to actively control the oil pump to return the swash plate to the center position. For the first solution, the main oil pump always works at the maximum displacement, the hydraulic system will produce a lot of energy loss, and cause the hydraulic oil temperature to rise. For the second solution, a pressure sensor is set, and the main pump is actively controlled by the electrical program to return the main pump swash plate to the center position. The control system is complex, the pressure cannot be maintained, the pressure adjustment and observation are inconvenient, the fault judgment is difficult, the maintenance and replacement of components are complicated, and the maintenance personnel are required to have high capabilities. Summary of the invention

[0004] The purpose of the present invention is to solve the deficiencies in the prior art, and therefore an electric proportional pump pressure cut-off control device and a concrete pump truck are proposed.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions:

[0006] An electric proportional pump pressure cut-off control device comprises a main oil pump variable cylinder, a hydraulic motor, a bidirectional variable pump, a hydraulic oil tank, a main oil cylinder 1, a main oil cylinder 2, an auxiliary oil circuit 1, an auxiliary oil circuit 2 and an auxiliary oil circuit 3, and also comprises a pressure control module, a shuttle valve, a check valve, a proportional valve and a reversing valve;

[0007] The two oil ports of the variable cylinder of the main oil pump are each installed with a one-way valve, the two one-way valves are connected to the pressure cut-off module through the main oil circuit 1, the pressure cut-off module is connected to the shuttle valve through the main oil circuit 2, and is connected to the hydraulic oil tank through the main oil circuit 3, and the two oil outlets of the shuttle valve are respectively connected to the two oil ports of the bidirectional variable pump;

[0008] The two oil ports of the variable cylinder of the main oil pump are connected to the same proportional valve, one oil outlet of the proportional valve is connected to the hydraulic oil tank, and the other oil outlet is connected to two parallel safety oil replenishing valves through the auxiliary oil line 3, and the auxiliary oil line 3 is equipped with a relief valve 1, which is connected to the hydraulic oil tank;

[0009] The oil outlets of the two safety oil replenishing valves are correspondingly connected to the two oil outlets of the bidirectional variable pump, and the oil outlets of the two safety oil replenishing valves are respectively connected to the main oil cylinder one and the main oil cylinder two through the auxiliary oil circuit one and the auxiliary oil circuit two, the auxiliary oil circuit one and the auxiliary oil circuit two are connected to the same reversing valve, the oil outlet of the reversing valve is connected to the overflow valve two, the overflow valve two is connected to the hydraulic motor, and the hydraulic motor is connected to the hydraulic oil tank.

[0010] According to a further preferred embodiment, the pressure cut-off module includes a unloading valve, a relief valve three and a damping hole, the unloading valve is connected to a damping hole and a relief valve three, the damping hole and the relief valve three are arranged in parallel, the relief valve three is connected to the shuttle valve through the main oil circuit two, and the damping hole is connected to the hydraulic oil tank through the main oil circuit three.

[0011] In a further preferred embodiment, the proportional valve is a three-position four-way electromagnetic proportional valve.

[0012] In a further preferred embodiment, the reversing valve is a three-position one-way reversing valve.

[0013] In a further preferred embodiment, the shuttle valve is an AND type shuttle valve.

[0014] A control method for an electric proportional pump pressure cut-off control device comprises the following steps:

[0015] First, the shuttle valve selects the pressure of the pressure oil at port A and port B of the system. When the pressure of the pressure oil reaches the set opening pressure of the relief valve three in the pressure cut-off module, the relief valve three opens, the oil flows through the damping hole, and generates pressure at point C in front of the damping hole. This pressure is used as the control pressure oil of the unloading valve. When the generated pressure reaches the set pressure of the unloading valve, the unloading valve opens, and the excess pressure oil flows to the hydraulic oil tank through the main oil line three. The pressure at its oil inlet D is reduced, causing the pressure oil in the variable cylinder of the main oil pump to leak out, and the displacement of the main oil pump is reduced, thereby achieving the overpressure protection effect.

[0016] A concrete pump truck comprises the above-mentioned electric proportional pump pressure cut-off control device.

[0017] Compared with the prior art, the present invention has the following beneficial effects:

[0018] The present invention installs a one-way valve, a pressure cut-off module connected to the two one-way valves, and a shuttle valve connected to the pressure cut-off module at the two chamber oil ports of the main oil pump variable cylinder respectively. The shuttle valve is used to select the high pressure of the pressure oil at the oil port of the main oil pump, and the pressure is used to act on the pressure cut-off valve. When the pressure reaches the set value of the pressure cut-off valve, the pressure oil in the variable cylinder of the main pump variable mechanism is unloaded through the pressure cut-off valve, and the pressure in the variable cylinder drops, thereby reducing the displacement of the oil pump and achieving overpressure protection. A one-way valve is respectively set at the two chamber oil ports of the main oil pump variable cylinder, and a pressure cut-off valve is set at the same time. The system pressure is selected through the shuttle valve. The one-way valve and the pressure cut-off valve group are externally connected to the main oil pump variable cylinder. The pressure of the main system is used to control the opening of the unloading valve. After the unloading valve is opened, the oil in the variable cylinder of the main oil pump returns to the oil tank through the unloading valve, so that the displacement of the main oil pump is reduced. Specifically, when the pressure of the hydraulic system rises to the set pressure of the relief valve three, the relief valve three is opened. Due to the flow of oil, pressure is generated in front of the damping hole. The pressure is used to open the unloading valve, and the oil in the variable cylinder of the main oil pump flows back to the oil tank through the one-way valve and the unloading valve, so that the oil in the variable cylinder of the main oil pump leaks out, the displacement of the main oil pump is reduced, and the energy loss of overflow is avoided, thereby protecting the main oil pump and the hydraulic system. It is an energy-saving control method. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a schematic diagram of the overall structure of the present invention.

[0020] In the figure: 1. Main oil pump variable cylinder; 2. Hydraulic motor; 3. Two-way variable cylinder; 4. Hydraulic cylinder; 5. Main oil cylinder one; 6. Main oil cylinder two; 7. Shuttle valve; 8. One-way valve; 9. Proportional valve; 10. Hot oil shuttle valve; 11. Main oil circuit two; 12. Main oil circuit three; 13. Auxiliary oil circuit three; 14. Safety oil replenishing valve; 15. Overflow valve one; 16. Auxiliary oil circuit one; 17. Auxiliary oil circuit two; 18. Overflow valve two; 19. Unloading valve; 20. Overflow valve three; 21. Damping hole; 22. Main oil circuit one. DETAILED DESCRIPTION

[0021] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments.

[0022] In the description of the present invention, it is necessary to understand that the terms "upper", "lower", "front", "back", "left", "right", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship are based on the orientation or position relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0023] Example:

[0024] like Figure 1 As shown, an electric proportional pump pressure cut-off control device includes a main oil pump variable cylinder 1, a hydraulic motor 2, a two-way variable pump 3, a hydraulic oil tank 4, a main oil cylinder 1 5, a main oil cylinder 2 6, an auxiliary oil circuit 1 16, an auxiliary oil circuit 2 17 and an auxiliary oil circuit 3 13, and also includes a pressure control module, a shuttle valve 7 (or an AND-type shuttle valve), a one-way valve 8, a proportional valve 9 (a three-position four-way electromagnetic proportional valve) and a hot oil shuttle valve 10 (a three-position one-way reversing valve);

[0025] The two chamber oil ports of the main oil pump variable cylinder 1 are both installed with a one-way valve 8, and the two one-way valves 8 are connected to the pressure cut-off module through the main oil circuit 1 22, and the pressure cut-off module is connected to the shuttle valve 7 through the main oil circuit 2 11 and connected to the hydraulic oil tank 4 through the main oil circuit 3 12, and the two oil outlets of the shuttle valve 7 are respectively connected to the two oil ports of the two-way variable pump 3;

[0026] The pressure cut-off module includes a relief valve 19, a relief valve 3 20 and a damping hole 21. The relief valve 19 is connected with a damping hole 21 and a relief valve 3 20. The damping hole 21 and the relief valve 3 20 are arranged in parallel. The relief valve 3 20 is connected to the shuttle valve 7 through the main oil circuit 2 11, and the damping hole 21 is connected to the hydraulic oil tank 4 through the main oil circuit 3 12. When the pressure of the hydraulic system rises to the set pressure of the relief valve 3 20, the relief valve 3 20 is opened. Due to the flow of oil, pressure is generated in front of the damping hole 21. The pressure is used to open the relief valve 19, and the oil in the variable cylinder 1 of the main oil pump flows back to the hydraulic oil tank 4 through the one-way valve 8 and the relief valve 19, so that the oil in the variable cylinder 1 of the main oil pump is discharged, and the overall displacement of the main oil pump is reduced, thereby avoiding the energy loss of overflow, protecting the main oil pump and the hydraulic system, and is an energy-saving control method.

[0027] The two-chamber oil ports of the main oil pump variable cylinder 1 are connected to the same proportional valve 9, one oil outlet of the proportional valve 9 is connected to the hydraulic oil tank 4, and the other oil outlet is connected to two parallel-arranged safety oil replenishing valves 14 through the auxiliary oil circuit 3 13, and an overflow valve 15 is installed on the auxiliary oil circuit 3 13, and the overflow valve 15 is connected to the hydraulic oil tank 4; the overflow valve 15 is used to protect the auxiliary oil circuit 3 13 to prevent the safety oil replenishing valve 14 from having excessive pressure once, which makes it impossible to accurately control the sequential action of multiple components, and at the same time, the proportional valve 9 is used to realize throttling control of the pressure oil flow of the two-chamber oil ports of the main oil pump variable cylinder 1 through electronic control, thereby realizing an energy-saving control system.

[0028] The oil outlets of the two safety oil replenishing valves 14 are correspondingly connected to the two oil outlets of the bidirectional variable pump 3, and the oil outlets of the two safety oil replenishing valves 14 are respectively connected to the main oil cylinder 1 5 and the main oil cylinder 2 6 through the auxiliary oil circuit 1 16 and the auxiliary oil circuit 2 17, and the auxiliary oil circuit 1 16 and the auxiliary oil circuit 2 17 are connected to the same hot oil shuttle valve 10, and the oil outlet of the hot oil shuttle valve 10 is connected to the overflow valve 2 18, and the overflow valve 2 18 is connected to the hydraulic motor 2, and the hydraulic motor 2 is connected to the hydraulic oil tank 4.

[0029] First, the shuttle valve 7 selects the pressure of the pressure oil at ports A and B in the figure. When the pressure of the pressure oil reaches the set opening pressure of the relief valve three 20 in the pressure cut-off module, the relief valve three 20 opens, and the oil flows through the damping hole 21 and generates pressure at C in front of the damping hole 21. The pressure is used as the control pressure oil of the unloading valve 19. When the generated pressure reaches the set pressure of the unloading valve 19, the unloading valve 19 opens, and the excess pressure oil flows to the hydraulic oil tank 4 through the main oil circuit 12. The pressure at its oil inlet D is reduced, so that the pressure oil in the variable cylinder 1 of the main oil pump is leaked, and the displacement of the main oil pump is reduced, thereby achieving the overpressure protection effect.

[0030] The system's action process is as follows:

[0031] When the two-way variable pump 3 supplies oil to the top (high pressure at port B and low pressure at port A), the pressure oil output by the two-way variable pump 3 enters the left chamber of the main oil cylinder 5 through the auxiliary oil circuit 16, and pushes the piston of the main oil cylinder 5 to squeeze toward the right chamber, the pressure oil in the right chamber of the main oil cylinder 5 flows to the pressure oil in the right chamber of the main oil cylinder 2 6, and causes the piston of the main oil cylinder 2 6 to squeeze toward the left chamber, and the pressure oil in the left chamber returns to the inside of the two-way variable pump 3 through the auxiliary oil circuit 2 17; after the two-way variable pump 3 is reversed, when the two-way variable pump 3 is supplied to the bottom, The oil is supplied from the main part (high pressure at port A and low pressure at port B), and the pressure oil output by the two-way variable pump 3 enters the left chamber of the main cylinder 26 through the auxiliary oil circuit 17, and pushes the piston of the main cylinder 26 to be squeezed toward the right chamber, and the pressure oil in the right chamber of the main cylinder 26 flows to the pressure oil in the right chamber of the main cylinder 15, and causes the piston of the main cylinder 15 to be squeezed toward the left chamber, and the pressure oil in the left chamber returns to the inside of the two-way variable pump 3 through the auxiliary oil circuit 16; the reversing action is achieved by changing the angle of the swash plate inside the variable pump from a positive angle to a negative angle. The safety oil replenishing valve 14 has two functions. When the pressure at port A (high pressure side) exceeds the set value of the safety oil replenishing valve 14, the safety oil replenishing valve 14 opens, and the oil returns to port B (low pressure side) through the one-way valve in the other safety oil replenishing valve 14; since the oil in the hot oil shuttle valve 10 only circulates between the two-way variable pump 3 and the cylinder, the hydraulic system is prone to heat up, so a hot oil shuttle valve 8 is set to replace the oil on the low-pressure side of the system for cooling. The specific action process is: when the B port is high pressure, the valve core of the hot oil shuttle valve 8 is switched to the upper state. At this time, the low-pressure side (low pressure at port A) flows back to the oil tank through the hot oil shuttle valve 8 and the overflow valve 2 18 for heat dissipation and cooling. Due to the leakage inside the two-way variable pump 3 and the hot oil shuttle valve 8 replacing the hot oil in the system, the volume of the oil in the system is reduced, so the system needs to be replenished with oil. The oil replenishment is achieved through the one-way valve in the safety oil replenishing valve 10, and the replenished oil comes from the pressure oil of the oil replenishing pump (oil circuit three III). The oil inlet of the manual reversing valve 11 is taken from the oil circuit III (at Ps) of the replenishing pump outlet. When the proportional valve solenoid is working, the proportional valve is in the left position, and the pressure oil enters the left chamber of the main oil pump variable cylinder 1, pushing the piston of the main oil pump variable cylinder 1 to move to the right, causing the pressure oil in the right chamber to enter the hydraulic oil tank 4. After the piston of the main oil pump variable cylinder 1 moves, the two-way variable pump 3 has displacement, realizing the emergency working condition; when the proportional valve solenoid is working, the proportional valve switches to the right position, and the pressure oil enters the right chamber of the main oil pump variable cylinder 1, pushing the piston of the main oil pump variable cylinder 1 to move to the left, causing the pressure oil in the left chamber to enter the hydraulic oil tank 1. After the piston of the main oil pump variable cylinder 1 moves, the two-way variable pump 4 has displacement, realizing the above-mentioned emergency working condition.

[0032] Embodiment 2:

[0033] During the operation of the above system, first, the shuttle valve 7 selects the pressure of the pressure oil at ports A and B in the figure. When the pressure of the pressure oil reaches the set opening pressure of the relief valve three 20 in the pressure cut-off module, the relief valve three 20 opens, and the oil flows through the damping hole 21 and generates pressure at the front C of the damping hole 21. The pressure is used as the control pressure oil of the unloading valve 19. When the generated pressure reaches the set pressure of the unloading valve 19, the unloading valve 19 opens, and the excess pressure oil flows to the hydraulic oil tank 4 through the main oil circuit three 12. The pressure at its oil inlet D is reduced, so that the pressure oil in the variable cylinder 1 of the main oil pump is leaked, and the displacement of the main oil pump is reduced, thereby achieving the overpressure protection effect.

[0034] The electric proportional pump pressure cut-off control device has been used in the concrete pump truck products produced by our company. The use effect has achieved the purpose of the invention. The hydraulic system works stably and reliably, and customers have good feedback. At the same time, it also significantly improves the life of the overpressure system.

[0035] The above is only a preferred specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. The replacement may be a replacement of a part of the structure, device, method step, or a complete technical solution. Any equivalent replacement or change according to the technical solution and the inventive concept of the present invention shall be covered within the protection scope of the present invention.

Claims

1. An electric proportional pump pressure cut-off control device, comprising a main oil pump variable cylinder (1), a hydraulic motor (2), a bidirectional variable pump (3), a hydraulic oil tank (4), a main oil cylinder 1 (5), a main oil cylinder 2 (6), an auxiliary oil circuit 1 (16), an auxiliary oil circuit 2 (17) and an auxiliary oil circuit 3 (13), characterized in that: It also includes a pressure control module, a shuttle valve (7), a one-way valve (8), a proportional valve (9) and a hot oil shuttle valve (10); The two oil ports of the main oil pump variable cylinder (1) are each equipped with a one-way valve (8), the two one-way valves (8) are connected to the pressure cut-off module through the main oil circuit 1 (22), the pressure cut-off module is connected to the shuttle valve (7) through the main oil circuit 2 (11), and is connected to the hydraulic oil tank (4) through the main oil circuit 3 (12), and the two oil outlets of the shuttle valve (7) are respectively connected to the two oil ports of the bidirectional variable pump (3); The two oil ports of the main oil pump variable cylinder (1) are connected to the same proportional valve (9), one oil outlet of the proportional valve (9) is connected to the hydraulic oil tank (4), and the other oil outlet is connected to two parallel-connected safety oil replenishing valves (14) via a secondary oil line three (13), and a relief valve one (15) is installed on the secondary oil line three (13), and the relief valve one (15) is connected to the hydraulic oil tank (4); The oil outlets of the two safety oil replenishing valves (14) are connected to the two oil outlets of the bidirectional variable pump (3) respectively, and the oil outlets of the two safety oil replenishing valves (14) are connected to the main oil cylinder 1 (5) and the main oil cylinder 2 (6) through the auxiliary oil circuit 1 (16) and the auxiliary oil circuit 2 (17) respectively, and the auxiliary oil circuit 1 (16) and the auxiliary oil circuit 2 (17) are connected to the same hot oil shuttle valve (10), and the oil outlet of the hot oil shuttle valve (10) is connected to the overflow valve 2 (18), and the overflow valve 2 (18) is connected to the hydraulic motor (2), and the hydraulic motor (2) is connected to the hydraulic oil tank (4); The pressure cut-off module comprises a relief valve (19), a relief valve (20) and a damping hole (21); the relief valve (19) is connected to a damping hole (21) and a relief valve (20); the damping hole (21) and the relief valve (20) are arranged in parallel; the relief valve (20) is connected to the shuttle valve (7) through the main oil circuit (11); and the damping hole (21) is connected to the hydraulic oil tank (4) through the main oil circuit (12); The proportional valve (9) is a three-position four-way electromagnetic proportional valve; The hot oil shuttle valve (10) is a three-position one-way reversing valve; The shuttle valve (7) is a shuttle valve of the or type; The control method comprises the following steps: First, the shuttle valve (7) selects the pressure of the pressure oil of the main oil cylinder 1 (5) and the main oil cylinder 2 (6) of the system. When the pressure of the pressure oil reaches the set opening pressure of the relief valve 3 (20) in the pressure cut-off module, the relief valve 3 (20) opens, the oil flows through the damping hole (21), and generates pressure in front of the damping hole (21). The pressure is used as the control pressure oil of the unloading valve (19). When the generated pressure reaches the set pressure of the unloading valve (19), the unloading valve (19) opens, and the excess pressure oil flows to the hydraulic oil tank (4) through the main oil line 3 (12). The oil inlet pressure is reduced, so that the pressure oil in the main oil pump variable cylinder (1) is leaked, and the displacement of the main oil pump is reduced, thereby achieving an overpressure protection effect.

2. A concrete pump truck, characterized in that: It comprises an electric proportional pump pressure cut-off control device as described in claim 1.

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