阅读说明：本技术 一种电比例泵压力切断控制装置及混凝土泵车 (Pressure cut-off control device for electric proportional pump and concrete pump truck ) 是由 陆远望 宋明见 于 2020-12-23 设计创作，主要内容包括：本发明公开一种电比例泵压力切断控制装置及混凝土泵车,属混凝土泵车泵送液压系统领域。在主油泵变量缸的两腔油口处分别安装一单向阀、与两个单向阀连接的压力切断模块、与压力切断模块连接的梭阀,利用梭阀选择出主油泵油口处压力油的高压力,用该压力作用于压力切断模块,当压力达到压力切断模块设定值后,主油泵变量缸内压力油通过压力切断模块卸荷,变量缸内的压力下降,从而实现油泵排量减小,实现超压保护。在主油泵变量缸两腔油口分别设置一只单向阀,同时设置压力切断模块,通过梭阀选择到系统压力,取主系统的压力控制卸荷阀打开,卸荷阀打开后,主油泵变量缸中油液经卸荷阀回油箱,使得主油泵排量减小。(The invention discloses an electric proportional pump pressure cut-off control device and a concrete pump truck, and belongs to the field of pumping hydraulic systems of concrete pump trucks. The pressure of the pressure oil at the oil port of the main oil pump variable cylinder is selected by the shuttle valve, the pressure acts 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 by the pressure cut-off module, the pressure in the variable cylinder is reduced, thereby realizing the reduction of the discharge capacity of the oil pump and realizing overpressure protection. The oil ports of two cavities of the variable cylinder of the main oil pump are respectively provided with a one-way valve, and simultaneously a pressure cut-off module is arranged, the system pressure is selected through a shuttle valve, the pressure of a main system is taken to control an unloading valve to be opened, and after the unloading valve is opened, oil in the variable cylinder of the main oil pump returns to an oil tank through the unloading valve, so that the discharge capacity of the main oil pump is reduced.)

1. A pressure cut-off control device of an electric proportional pump comprises a variable cylinder (1) of a main oil pump, a hydraulic motor (2), a bidirectional variable pump (3), a hydraulic oil tank (4), a first main oil cylinder (5), a second main oil cylinder (6), a first auxiliary oil way (16), a second auxiliary oil way (17) and a third auxiliary oil way (13),

the device also comprises a pressure control module, a shuttle valve (7), a one-way valve (8), a proportional valve (9) and a hot oil shuttle valve (10);

two oil ports of the main oil pump variable cylinder (1) are respectively provided with a one-way valve (8), the two one-way valves (8) are connected with a pressure cut-off module through a main oil way I (22), the pressure cut-off module is connected with a shuttle valve (7) through a main oil way II (11) and is connected with a hydraulic oil tank (4) through a main oil way III (12), and two oil outlets of the shuttle valve (7) are respectively connected with two oil ports of the bidirectional variable pump (3);

two oil ports of the main oil pump variable cylinder (1) are connected with the same proportional valve (9), one oil outlet of the proportional valve (9) is connected with the hydraulic oil tank (4), the other oil outlet of the proportional valve is connected with two safety oil replenishing valves (14) which are arranged in parallel through an auxiliary oil way III (13), an overflow valve I (15) is installed on the auxiliary oil way III (13), and the overflow valve I (15) is connected with the hydraulic oil tank (4);

the oil outlets of the two safe oil replenishing valves (14) are correspondingly connected with two oil ports of the bidirectional variable pump (3), the oil outlets of the two safe oil replenishing valves (14) are respectively connected with the first main oil cylinder (5) and the second main oil cylinder (6) through a first auxiliary oil way (16) and a second auxiliary oil way (17), the first auxiliary oil way (16) and the second auxiliary oil way (17) are connected with the same hot oil shuttle valve (10), the oil outlet of the hot oil shuttle valve (10) is connected with a second overflow valve (18), the second overflow valve (18) is connected with the hydraulic motor (2), and the hydraulic motor (2) is connected with the hydraulic oil tank (4).

2. The pressure cut-off control device for the electric proportional pump according to claim 1, wherein the pressure cut-off module comprises an unloading valve (19), a third overflow valve (20) and a damping hole (21), the unloading valve (19) is connected with the damping hole (21) and the third overflow valve (20), the damping hole (21) and the third overflow valve (20) are arranged in parallel, the third overflow valve (20) is connected with the shuttle valve (7) through a second main oil way (11), and the damping hole (21) is connected with the hydraulic oil tank (4) through a third main oil way (12).

3. An electric proportional pump pressure cut-off control device according to claim 1, characterized in that said proportional valve (9) is a three-position four-way electromagnetic proportional valve.

4. The electric proportional pump pressure cutoff control device according to claim 1, wherein the hot oil shuttle valve (10) is a three-position one-way reversing valve.

5. An electro-proportional pump pressure cutoff control device according to claim 1, characterized in that the shuttle valve (7) is an and type shuttle valve.

6. The control method of an electric proportional pump pressure cutoff control device according to any one of claims 1 to 5, characterized by comprising the steps of:

the pressure of pressure oil of an A port and a B port of a system is selected by a shuttle valve (7), when the pressure of the pressure oil reaches the set opening pressure of a relief valve III (20) in a pressure cutoff module, the relief valve III (20) is opened, the oil flows through a damping hole (21), pressure is generated in front of the damping hole (21) and is used as control pressure oil of an unloading valve (19), when the generated pressure reaches the set pressure of the unloading valve (19), the unloading valve (19) is opened, redundant pressure oil flows to a hydraulic oil tank (4) through a main oil way III (12), the pressure at an oil inlet D of the hydraulic oil tank is reduced, the pressure oil in a main oil pump variable cylinder (1) is discharged, the discharge capacity of a main oil pump is reduced, and the overpressure protection effect is further realized.

7. A concrete pump truck comprising an electric proportional pump pressure cutoff control device according to any one of claims 1 to 5.

Technical Field

The invention relates to the technical field of pumping hydraulic systems of concrete pump trucks, in particular to an electric proportional pump pressure cut-off control device and a concrete pump truck.

Background

The pumping hydraulic system is a main component of a concrete pump truck, and the reliability of the pumping hydraulic system also directly determines the performance of the whole truck. Overpressure protection is a function required by a common pumping hydraulic system and is used for protecting the hydraulic system in case of system failure.

However, the prior art adopts two schemes: one solution is to provide a safety valve, and the system can be protected only by overflowing the safety overflow valve after overpressure, and in this case, the system will generate a large amount of heat; the other scheme is that the oil pump is controlled by an electric program, and the oil pump is controlled actively to return the swash plate to the middle position. In the first solution, the main oil pump always operates at the maximum displacement, and the hydraulic system generates a great deal of energy loss and causes the temperature of the hydraulic oil to rise. For the second scheme, a pressure sensor is arranged, the main pump is actively controlled through an electric program to enable the main pump swash plate to return to the middle position, the control system is complex, the pressure cannot be kept, the pressure adjustment and observation are inconvenient, the fault judgment difficulty is large, the maintenance and replacement of elements are complex, and the requirement on the capability of maintenance personnel is high.

Disclosure of Invention

The invention aims to solve the defects in the prior art, and provides an electric proportional pump pressure cut-off control device and a concrete pump truck.

In order to achieve the purpose, the invention adopts the following technical scheme:

a pressure cut-off control device of an electric proportional pump comprises a variable cylinder of a main oil pump, a hydraulic motor, a bidirectional variable pump, a hydraulic oil tank, a first main oil cylinder, a second main oil cylinder, a first auxiliary oil way, a second auxiliary oil way and a third auxiliary oil way, and further comprises a pressure control module, a shuttle valve, a one-way valve, a proportional valve and a reversing valve;

two oil ports of the variable cylinder of the main oil pump are respectively provided with a one-way valve, the two one-way valves are connected with a pressure cutting module through a first main oil way, the pressure cutting module is connected with a shuttle valve through a second main oil way and is connected with a hydraulic oil tank through a third main oil way, and two oil outlets of the shuttle valve are respectively connected with the two oil ports of the bidirectional variable pump;

two oil ports of the variable cylinder of the main oil pump are connected with the same proportional valve, one oil outlet of the proportional valve is connected with a hydraulic oil tank, the other oil outlet of the proportional valve is connected with two safety oil replenishing valves which are arranged in parallel through an auxiliary oil way III, an overflow valve I is installed on the auxiliary oil way III, and the overflow valve I is connected with the hydraulic oil tank;

the oil outlets of the two safe oil replenishing valves are correspondingly connected with the two oil ports of the bidirectional variable pump, the oil outlets of the two safe oil replenishing valves are respectively connected with the first main oil cylinder and the second main oil cylinder through a first auxiliary oil way and a second auxiliary oil way, the first auxiliary oil way and the second auxiliary oil way are connected with the same reversing valve, the oil outlet of the reversing valve is connected with a second overflow valve, the second overflow valve is connected with a hydraulic motor, and the hydraulic motor is connected with a hydraulic oil tank.

In a further preferred scheme, the pressure cutoff module comprises an unloading valve, a third overflow valve and a damping hole, the unloading valve is connected with the first damping hole and the third overflow valve, the damping hole and the third overflow valve are connected in parallel, the third overflow valve is connected with the shuttle valve through a second main oil way, and the damping hole is connected with the hydraulic oil tank through a third main oil way.

Further preferably, the proportional valve is a three-position four-way electromagnetic proportional valve.

Further preferably, the reversing valve is a three-position one-way reversing valve.

Further preferably, the shuttle valve is an AND type shuttle valve.

A control method of an electric proportional pump pressure cut-off control device comprises the following steps:

the pressure of pressure oil of an A port and a B port of the system is selected by the shuttle valve, when the pressure of the pressure oil reaches the set opening pressure of a third overflow valve in the pressure cut-off module, the third overflow valve is opened, the oil flows through the damping hole, pressure is generated at the front C of the damping hole and is used as control pressure oil of the unloading valve, when the generated pressure reaches the set pressure of the unloading valve, the unloading valve is opened, the pressure of redundant pressure oil or the pressure of the redundant pressure oil flowing to the hydraulic oil tank through a main oil path is reduced, the pressure oil in a variable cylinder of the main oil pump is discharged, the discharge capacity of the main oil pump is reduced, and the overpressure protection effect is further realized.

A concrete pump truck comprises the electric proportional pump pressure cut-off control device.

Compared with the prior art, the invention has the following beneficial effects:

the invention respectively installs a one-way valve, a pressure cut-off module connected with the two one-way valves and a shuttle valve connected with the pressure cut-off module at the oil ports of the two cavities of the variable cylinder of the main oil pump, the shuttle valve is used for selecting the high pressure of the pressure oil at the oil ports of the main oil pump, the pressure is used for acting 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 variable mechanism of the main oil pump is unloaded through the pressure cut-off valve, the pressure in the variable cylinder is reduced, thereby realizing the reduction of the. The oil ports of two cavities of the variable cylinder of the main oil pump are respectively provided with a one-way valve and a pressure cut-off valve, the system pressure is selected through a shuttle valve, the variable cylinder of the main oil pump is externally connected with the one-way valve and a pressure cut-off valve group, the pressure of a main system is used for controlling the opening of an unloading valve, and after the unloading valve is opened, oil in the variable cylinder of the main oil pump returns to an oil tank through the unloading valve, so that the discharge capacity of the main oil pump is reduced. When the pressure of the hydraulic system rises to the set pressure of the overflow valve III, the overflow valve III is opened, the pressure is generated in front of the damping hole due to the flow of the oil, the unloading valve is opened by utilizing the pressure, the oil in the variable cylinder of the main oil pump flows back to the oil tank through the unloading valve through the one-way valve, so that the oil in the variable cylinder of the main oil pump is discharged, the discharge capacity of the main oil pump is reduced, the energy loss of overflow is avoided, and the main oil pump and the hydraulic system are protected.

Drawings

Fig. 1 is a schematic view of the overall structure of the present invention.

In the figure: 1. a main oil pump variable cylinder; 2. a hydraulic motor; 3. a bidirectional variable cylinder; 4. a hydraulic cylinder; 5. a first main oil cylinder; 6. a second main oil cylinder; 7. a shuttle valve; 8. a one-way valve; 9. a proportional valve; 10. a hot oil shuttle valve; 11. a main oil way II; 12. a main oil way III; 13. a secondary oil way III; 14. a safety oil supply valve; 15. a first overflow valve; 16. a first auxiliary oil way; 17. a secondary oil way II; 18. an overflow valve II; 19. an unloading valve; 20. an overflow valve III; 21. a damping hole; 22. the first main oil way.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments.

In the description of the present invention, it is to be understood that the terms "upper", "lower", "front", "rear", "left", "right", "top", "bottom", "inner", "outer", and the like, indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, are merely for convenience in describing the present invention and simplifying the description, and do not indicate or imply that the device or element being referred to must have a particular orientation, be constructed and operated in a particular orientation, and thus, should not be construed as limiting the present invention.

Example (b):

as shown in fig. 1, an electric proportional pump pressure cutoff control device includes 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 one 5, a main oil cylinder two 6, an auxiliary oil circuit one 16, an auxiliary oil circuit two 17, an auxiliary oil circuit three 13, a pressure control module, a shuttle valve 7 (or an and-type shuttle valve), a check 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);

two oil ports of the main oil pump variable cylinder 1 are respectively provided with a one-way valve 8, the two one-way valves 8 are connected with a pressure cut-off module through a main oil way I22, the pressure cut-off module is connected with a shuttle valve 7 through a main oil way II 11 and is connected with a hydraulic oil tank 4 through a main oil way III 12, and two oil outlets of the shuttle valve 7 are respectively connected with two oil ports of the bidirectional variable pump 3;

the pressure cut-off module comprises an unloading valve 19, a third overflow valve 20 and a damping hole 21, the unloading valve 19 is connected with the damping hole 21 and the third overflow valve 20, the damping hole 21 and the third overflow valve 20 are arranged in parallel, the third overflow valve 20 is connected with the shuttle valve 7 through a second main oil way 11, and the damping hole 21 is connected with the hydraulic oil tank 4 through a third main oil way 12. When the pressure of the hydraulic system rises to the set pressure of the overflow valve III 20, the overflow valve III 20 is opened, the unloading valve 19 is opened by utilizing the pressure because the pressure is generated before the damping hole 21 by the flowing of the oil, the oil in the variable cylinder 1 of the main oil pump flows back to the hydraulic oil tank 4 through the unloading valve 19 through the one-way valve 8, so that the oil in the variable cylinder 1 of the main oil pump is discharged, the integral displacement of the main oil pump is reduced, the energy loss of overflow is avoided, and the main oil pump and the hydraulic system are protected.

Two cavities of oil ports of the main oil pump variable cylinder 1 are connected with the same proportional valve 9, one oil outlet of the proportional valve 9 is connected with the hydraulic oil tank 4, the other oil outlet of the proportional valve 9 is connected with two safety oil supplementing valves 14 which are arranged in parallel through an auxiliary oil way III 13, an overflow valve I15 is installed on the auxiliary oil way III 13, and the overflow valve I15 is connected with the hydraulic oil tank 4; the overflow valve I5 is used for preventing the safety oil supplementing valve 14 from being incapable of accurately controlling the sequential actions of a plurality of elements due to the fact that one-time pressure is too large, and meanwhile, the proportional valve 9 is used for achieving throttling control over the pressure oil flow of the oil ports of the two cavities of the main oil pump variable cylinder 1 in an electric control mode, and therefore the energy-saving control system is achieved.

The oil outlets of the two safety oil replenishing valves 14 are correspondingly connected with two oil ports of the bidirectional variable pump 3, the oil outlets of the two safety oil replenishing valves 14 are respectively connected with the first main oil cylinder 5 and the second main oil cylinder 6 through a first auxiliary oil way 16 and a second auxiliary oil way 17, the first auxiliary oil way 16 and the second auxiliary oil way 17 are connected with the same hot oil shuttle valve 10, the oil outlet of the hot oil shuttle valve 10 is connected with a second overflow valve 18, the second overflow valve 18 is connected with the hydraulic motor 2, and the hydraulic motor 2 is connected with the hydraulic oil tank 4.

The shuttle valve 7 selects the pressure of the pressure oil at the port A and the port B in the figure, when the pressure of the pressure oil reaches the set opening pressure of the overflow valve III 20 in the pressure cut-off module, the overflow valve III 20 is opened, the oil flows through the damping hole 21, pressure is generated at the front C of the damping hole 21 and is used as 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 is opened, redundant pressure oil flows to the hydraulic oil tank 4 through the main oil path 12, the pressure at the oil inlet D is reduced, the pressure oil in the variable cylinder 1 of the main oil pump is discharged, the discharge capacity of the main oil pump is reduced, and the overpressure protection effect is further realized.

The action process of the system is as follows:

when the bidirectional variable pump 3 supplies oil to the top (the port B is high in pressure and the port A is low in pressure), pressure oil output by the bidirectional variable pump 3 enters a left cavity of a main oil cylinder I5 through an auxiliary oil way I16 and pushes a piston of the main oil cylinder I5 to extrude towards a right cavity, pressure oil in the right cavity of the main oil cylinder I5 flows to pressure oil in the right cavity of a main oil cylinder II 6, the piston of the main oil cylinder II 6 is extruded towards the left cavity, and the pressure oil in the left cavity returns to the inside of the bidirectional variable pump 3 through an auxiliary oil way II 17; after the bidirectional variable pump 3 is reversed, when the bidirectional variable pump 3 supplies oil to the bottom (the port A is high in pressure and the port B is low in pressure), pressure oil output by the bidirectional variable pump 3 enters a left cavity of the main oil cylinder II 6 through the auxiliary oil way II 17 and pushes a piston of the main oil cylinder II 6 to extrude towards the right cavity, pressure oil in the right cavity of the main oil cylinder II 6 flows to pressure oil in the right cavity of the main oil cylinder I5, the piston of the main oil cylinder I5 is extruded towards the left cavity, and the pressure oil in the left cavity returns to the inside of the bidirectional variable pump 3 through the auxiliary oil way I16; the reversing action is realized by changing the angle of a swash plate inside the variable displacement pump from a positive angle to a negative angle. The safety oil supplementing valve 14 has two functions, when the pressure of the port A (high pressure side) exceeds the set value of the safety oil supplementing valve 14, the safety oil supplementing valve 14 is opened, and the oil returns to the port B (low pressure side) through a one-way valve in the other safety oil supplementing valve 14; the hot oil shuttle valve 10 is only circulated between the bidirectional variable pump 3 and the oil cylinder due to oil, a hydraulic system is easy to heat, and the hot oil shuttle valve 8 is arranged to replace oil on the low-pressure side in the system for cooling, and the specific action process is as follows: when the pressure of the port B is high, the valve core of the hot oil shuttle valve 8 is switched to an upper state, at the moment, the low-pressure side (the low pressure of the port A) flows back to the oil tank through the hot oil shuttle valve 8 through the overflow valve II 18 for heat dissipation and cooling, the oil volume in the system is reduced due to leakage in the bidirectional variable pump 3 and replacement of hot oil in the system by the hot oil shuttle valve 8, so that oil needs to be supplemented to the system, the oil supplement is realized through a one-way valve in the safe oil supplement valve 10, and the supplemented oil comes from pressure oil (an oil way III) of the oil supplement pump. The oil inlet of the manual reversing valve 11 is taken from the oil outlet circuit III (Ps) of the oil supplementing pump, when the proportional valve electromagnet works, the proportional valve is in a left position state, pressure oil enters a left cavity of the variable cylinder 1 of the main oil pump to push the piston of the variable cylinder 1 of the main oil pump to move rightwards, so that the pressure oil in a right cavity enters the hydraulic oil tank 4, and the bidirectional variable pump 3 has displacement after the piston of the variable cylinder 1 of the main oil pump moves, so that an emergency working condition is realized; when the proportional valve electromagnet works, the proportional valve is switched to a right position state, pressure oil enters a right cavity of the variable cylinder 1 of the main oil pump, a piston of the variable cylinder 1 of the main oil pump is pushed to move leftwards, so that the pressure oil in a left cavity enters the hydraulic oil tank 1, and the bidirectional variable pump 4 has displacement after the piston of the variable cylinder 1 of the main oil pump moves, so that the emergency working condition is realized.

Example 2:

in the working process of the system, firstly, the shuttle valve 7 selects the pressure of the pressure oil at the port A and the port B in the figure, when the pressure of the pressure oil reaches the set opening pressure of the overflow valve III 20 in the pressure cut-off module, the overflow valve III 20 is opened, the oil flows through the damping hole 21, pressure is generated in the front C of the damping hole 21 and is used as 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 is opened, redundant pressure oil flows to the hydraulic oil tank 4 through the main oil line III 12, the pressure at the oil inlet D is reduced, the pressure oil in the main oil pump variable cylinder 1 is discharged, the discharge capacity of the main oil pump is reduced, and the overpressure protection effect is further realized.

The pressure cut-off control device for the electric proportional pump is used for concrete pump truck products produced by the company, the using effect achieves the purpose of the invention, the hydraulic system works stably and reliably, the customer response is good, and meanwhile, the service life of an overpressure system is obviously prolonged.

The above description is only a preferred embodiment of the present invention, but the scope of the present invention is not limited thereto. The substitution may be of partial structures, devices, method steps, or may be a complete solution. The technical solution and the inventive concept thereof according to the present invention should be equally replaced or changed within the protection scope of the present invention.