Electric control rotary cushion valve for crane

Abstract

An electric control rotary cushion valve for a crane comprises a main reversing valve, one side of the main reversing valve is connected with an oil inlet P and an oil return port R, the oil inlet P is connected with a main overflow valve, the other side of the main reversing valve is connected with a working port AM, a working port BM and a secondary overflow valve, and two control ends of the main reversing valve are connected with electric proportional pressure reducing valves. A control cavity of the secondary overflow valve is connected with a free rotation electromagnetic valve, and the free rotation electromagnetic valve is connected with an oil return opening R through an electric proportional overflow valve. The main reversing valve is provided with the bypass throttle valve, and the control end of the main valve adopts electric proportional control, so that pressure impact in a control oil path can be eliminated, and stable input is realized; the oil return port is connected with the one-way throttle valve in series, so that the impact of oil liquid is effectively reduced while certain back pressure is provided for the system; in addition, the electric proportional overflow valve is adopted in the free rotation oil way, the overflow pressure value can be set at any time according to needs, free rotation action can be controlled at any time, system back pressure is adjusted, and pressure impact is reduced.

Description

Technical Field

[0001] The utility model relates to the technical field of construction machinery, in particular to an electric control swing buffer valve for a crane. Background Art

[0002] A truck crane is a construction machinery for hoisting operations. Since the objects to be hoisted are large in volume, heavy in weight and some require precise positioning, the requirements for the micro-mobility and stability of the truck crane are very high. Among the four major mechanisms in the hoisting operation, the problems of micro-mobility and stability have been solved for the hoisting, luffing and telescoping mechanisms. However, due to the large moment of inertia of the slewing mechanism, the impact problem during starting and stopping has not been effectively solved, which seriously affects the overall performance of the whole machine. Unstable slewing and large impact are often due to the large weight of the slewing structure of the crane, resulting in a large moment of inertia. When starting and stopping the slewing, the moment of inertia cannot be released, resulting in the shaking of the superstructure components. The swing buffer valve is a directional control valve used to control the slewing mechanism of a truck crane, and most of them adopt an open-core six-way structure to achieve smooth control of slewing by distributing the sizes of the inlet oil and bypass flow.

[0003] In the prior art, the commutation methods of the oil circuit directional control valve are hydraulic control commutation or electromagnetic commutation. Hydraulic control commutation cannot achieve linear control, the pilot pressure is prone to fluctuations, impact is easily generated during commutation, and there is also a problem of slow response at the same time; for electromagnetic commutation, since the electromagnetic valve generally has limited thrust, the design of the valve stem structure and spring stiffness is restricted, it is not suitable for large-flow systems, resulting in limited application range, and there is also a problem of easy impact during commutation. In addition, the oil circuit directional control valve has no redundant flow bypass function in the left and right working positions, and the redundant flow at the P port will cause system pressure build-up. At the same time, pressure and flow are prone to fluctuations during commutation, causing jitter problems of the actuator. Moreover, in the prior art, the bypass relief valve is an adjustable relief valve. Although the pressure is adjustable, the preset pressure value is generally calibrated by the supplier at the time of factory shipment, and the pressure value cannot be changed during use, and it is not convenient to change the pressure value when stopping the system, and the calibration is inaccurate.

[0004] Therefore, there is an urgent need in the industry to solve the problem of swing micro-mobility. Summary of the Invention

[0005] The technical problem to be solved by the utility model is to overcome the above-mentioned deficiencies of the prior art and provide an electric control swing buffer valve for a crane with a simple structure and good effect.

[0006] The utility model is realized by the following technical solutions: An electro-hydraulic slewing buffer valve for a crane, including a main reversing valve. One side of the main reversing valve is connected to an oil inlet P and an oil return port R. The oil inlet P is connected with a main relief valve. The other side of the main reversing valve is connected to a working port AM and a working port BM. Secondary relief valves are provided between the working port AM and the working port BM and the oil return port R respectively. Both control ends of the main reversing valve are connected with electro-hydraulic proportional pressure reducing valves. The control chamber of the secondary relief valve is connected with a free slewing solenoid valve. The free slewing solenoid valve is connected with the oil return port R through an electro-hydraulic proportional relief valve.

[0007] Furthermore, the main reversing valve is a three-position six-way hydraulically controlled reversing valve.

[0008] Sealing steel balls, return springs and plug screws are symmetrically arranged on the main reversing valve rod of the main reversing valve. A bypass throttle groove is arranged on the main reversing valve rod.

[0009] An oil return one-way throttle valve is provided between the main reversing valve and the oil return port R.

[0010] The electro-hydraulic proportional relief valve is connected with the oil return port R through the main reversing valve and the oil return one-way throttle valve.

[0011] An oil replenishing one-way valve is provided between the working port AM and the working port BM and the oil return port R. The oil replenishing one-way valve is connected with the oil return port R through the oil return one-way throttle valve.

[0012] A control port damper is provided between the electro-hydraulic proportional pressure reducing valve and the control end of the main reversing valve.

[0013] A one-way valve is provided between the control chamber of the secondary relief valve and the free slewing solenoid valve.

[0014] The free slewing solenoid valve is a two-position two-way hydraulically controlled reversing valve.

[0015] The utility model has the following advantages: For the electro-hydraulic slewing buffer valve of the crane of the utility model, a bypass throttle valve is arranged on the valve rod of the main reversing valve, and the control end of the main valve adopts electro-hydraulic proportional control with increased damping at the control end, which can eliminate the pressure impact in the control oil circuit, realize smooth input and gentle operation; at the same time, a one-way throttle valve is connected in series at the oil return port, which can effectively reduce the impact of the oil fluid while providing a certain back pressure for the system; in addition, the free slewing oil circuit adopts an electro-hydraulic proportional relief valve, and the relief pressure value can be set at any time as needed to control the free slewing action at any time, adjust the system back pressure, reduce the pressure impact and reduce the swaying of the upper structure. Description of the Drawings

[0016] The accompanying drawings, as part of the present utility model, are used to provide a further understanding of the present utility model. The schematic embodiments and descriptions thereof of the present utility model are used to explain the present utility model, but do not constitute an improper limitation to the present utility model. Obviously, the accompanying drawings in the following description are only some embodiments. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0017] In the accompanying drawings:

[0018] Figure 1 is the hydraulic schematic diagram of the present utility model;

[0019] Figure 2 is the structural schematic diagram of the main control valve of the present utility model;

[0020] Figure 3 is the structural schematic diagram of the valve stem of the main control valve of the present utility model.

[0021] In the figure: 1. Main control valve, 2. Main relief valve, 3. Return oil one-way throttle valve, 4. Make-up oil one-way valve, 5. Secondary relief valve, 6. Electro-hydraulic proportional reducing valve, 7. Control port damper, 8. Free rotation solenoid valve, 9. Electro-hydraulic proportional relief valve, 1-1. Main control valve stem, 1-2. Sealing steel ball, 1-3. Return spring, 1-4. Plug.

[0022] It should be noted that these accompanying drawings and text descriptions are not intended to limit the concept scope of the present utility model in any way, but to illustrate the concept of the present utility model for those skilled in the art by referring to specific embodiments. Detailed implementation manners

[0023] To make the objectives, technical solutions and advantages of the embodiments of the present utility model clearer, the following will clearly and completely describe the technical solutions in the embodiments of the present utility model in conjunction with the accompanying drawings in the embodiments of the present utility model. The following embodiments are used to illustrate the present utility model, but are not used to limit the scope of the present utility model.

[0024] In the description of the present utility model, it should be noted that the orientation or positional relationship indicated by the terms "upper", "lower", "front", "rear", "left", "right", "vertical", "inner", "outer", etc. is based on the orientation or positional relationship shown in the accompanying drawings. It is only for the convenience of describing the present utility model 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 should not be construed as a limitation to the present utility model.

[0025] In the description of the present utility model, it should be noted that unless otherwise clearly specified and defined, the terms "installation", "connection", and "coupling" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium. For those of ordinary skill in the art, the specific meanings of the above terms in the present utility model can be understood according to specific circumstances.

[0026] As Figures 1 to 3 shown, an electro-hydraulic rotary buffer valve for a crane includes a main reversing valve 1. One side of the main reversing valve 1 is connected to an oil inlet P and an oil return port R. The oil inlet P is connected to a main relief valve 2. The other side of the main reversing valve 1 is connected to a working port AM and a working port BM. Secondary relief valves 5 are provided between the working port AM and the working port BM and the oil return port R. Both control ends of the main reversing valve 1 are connected to electro-hydraulic proportional reducing valves 6. The control chamber of the secondary relief valve 5 is connected to a free rotation solenoid valve 8. The free rotation solenoid valve 8 is connected to the oil return port R through an electro-hydraulic proportional relief valve 9. The electro-hydraulic rotary buffer valve for a crane of the present utility model is provided with a main reversing valve. A main relief valve and a secondary relief valve are respectively provided on both sides of the main reversing valve. The main relief valve is arranged at the oil inlet P. When the pressure at the oil inlet P of the valve is too high, the oil can be overflowed to the valve oil return port R through the main relief valve, avoiding the danger problem caused by too high pressure at the oil inlet P. The secondary relief valve is arranged at the working ports AM and BM, which can prevent the sudden increase of the hydraulic oil at the working ports from affecting the hydraulic components. The pilot control port of the main reversing valve adopts the form of electro-hydraulic proportional control. When the main reversing valve needs to reverse left or right, the electro-hydraulic proportional reducing valve is used to control the magnitude of the control pressure input to the main reversing valve, thereby controlling the displacement of the valve stem of the main reversing valve, and finally realizing linear control. This structure has the characteristics of sensitive response, high repeatability accuracy, and small hysteresis. In addition, the control chamber of the secondary relief valve is connected to the free rotation solenoid valve and the electro-hydraulic proportional relief valve. The free rotation solenoid valve and the electro-hydraulic proportional relief valve participate in the free rotation oil circuit. When free rotation is required, the main reversing valve is in the middle working position. The free rotation solenoid valve is energized and reversed. The electro-hydraulic proportional relief valve can set the overflow pressure value at any time according to needs. The high-pressure oil at the working port AM or BM passes through the control chamber of the secondary relief valve and the free rotation solenoid valve and reaches the electro-hydraulic proportional relief valve. After the pressure at the working port exceeds the pressure setting value of the electro-hydraulic proportional relief valve, it overflows to the valve oil return port, realizing the free rotation function. The pressure setting value of the electro-hydraulic proportional relief valve can be adjusted during the free rotation working condition to control the free rotation action at any time, adjust the system back pressure, reduce the pressure shock, and reduce the swaying of the superstructure components.

[0027] As Figures 1 to 3An electro-hydraulic slewing buffer valve for a crane as shown. The main reversing valve 1 is a three-position six-way hydraulically controlled reversing valve. Sealing steel balls 1-2, return springs 1-3 and plug 1-4 are symmetrically arranged on the main reversing valve stem 1-1 of the main reversing valve 1. A bypass throttle groove is provided on the main reversing valve stem 1-1. The main reversing valve of the present utility model is a three-position six-way hydraulically controlled reversing valve. When the main reversing valve is in the left position, the working port AM is supplied with oil, and the working port BM returns oil. When the main reversing valve is in the right position, the working port AM returns oil, and the working port BM is supplied with oil. When the main reversing valve is in the middle position, the working ports AM and BM are closed, and the oil inlet P and the oil return port R are connected for oil return. Among them, bypass throttle grooves are opened on both sides of the middle working position on the valve stem of the main reversing valve. When switching from the middle working position to the left working position or to the right working position, in the form of full-stroke bypass, the hydraulic oil gradually decreases, which can reduce the pressure shock at the moment of reversing opening, realize a gentle moment of reversing opening, and make the full-stroke control more stable.

[0028] As Figure 1 An electro-hydraulic slewing buffer valve for a crane as shown. A return oil one-way throttle valve 3 is provided between the main reversing valve 1 and the oil return port R. The electro-hydraulic proportional relief valve 9 is connected to the oil return port R through the main reversing valve 1 and the return oil one-way throttle valve 3. The return oil port of the present utility model is in series with a one-way throttle valve, which can effectively reduce the impact of oil while providing a certain back pressure for the system. At the same time, it does not affect the system's oil suction from the valve oil return port R when the system needs to replenish oil.

[0029] As Figure 1 An electro-hydraulic slewing buffer valve for a crane as shown. A make-up oil one-way valve 4 is provided between the working ports AM and BM and the oil return port R. The make-up oil one-way valve 4 is connected to the oil return port R through the return oil one-way throttle valve 3.

[0030] As Figure 1 An electro-hydraulic slewing buffer valve for a crane as shown. A control port damper 7 is provided between the electro-hydraulic proportional pressure reducing valve 6 and the control end of the main reversing valve 1. The present utility model is provided with a control port damper between the electro-hydraulic proportional pressure reducing valve and the main reversing valve, which can eliminate the pressure shock in the control oil circuit, realize smooth input and gentle control.

[0031] As Figure 1 An electro-hydraulic slewing buffer valve for a crane as shown. A one-way valve is provided between the control chamber of the secondary relief valve 5 and the free slewing solenoid valve 8. The free slewing solenoid valve 8 is a two-position two-way hydraulically controlled reversing valve.

[0032] For the electric control rotary buffer valve of the crane of the present utility model, the pilot control port of the main reversing valve adopts the form of electro-hydraulic proportional control. At the same time, damping is added to the control end, so that linear control can be achieved, which has the characteristics of sensitive response, high repeatability accuracy, and small hysteresis. It can also eliminate pressure shock at the control end, achieve smooth input and gentle operation. In addition, the valve rod of the main reversing valve adopts the form of full-stroke bypass, so that the opening at the moment of commutation is gentle and the operation is smooth throughout the stroke. The oil return port is connected in series with a one-way throttle valve, which can effectively reduce the oil impact. The free rotation oil circuit adopts an electro-hydraulic proportional relief valve, and the relief pressure value can be set at any time according to needs. When in the free rotation working condition, the system back pressure can be adjusted to reduce the pressure shock and reduce the swaying of the superstructure components.

[0033] In the specification provided here, a large number of specific details are described. However, it can be understood that the embodiments of the present utility model can be practiced without these specific details. In some instances, well-known methods, structures, and technologies are not shown in detail so as not to obscure the understanding of this specification.

[0034] In addition, those skilled in the art can understand that although some of the embodiments described herein include certain features contained in other embodiments rather than other features, the combination of the features of different embodiments also means that it is within the protection scope of the present utility model and forms different embodiments. For example, in the above embodiments, those skilled in the art can use them in combination according to the known technical solutions and the technical problems to be solved by this application.

[0035] The above are only the preferred embodiments of the present utility model, and do not impose any form of limitation on the present utility model. Although the present utility model has been disclosed above with the preferred embodiments, it is not intended to limit the present utility model. Any person skilled in the art of this patent, without departing from the scope of the technical solution of the present utility model, can make some changes or modifications to the above-mentioned technical content by using the above-mentioned hints to form equivalent embodiments of equivalent changes. However, as long as it does not depart from the content of the technical solution of the present utility model, any simple modification, equivalent change, and modification made to the above embodiments according to the technical essence of the present utility model still fall within the scope of the technical solution of the present utility model.

Claims

1. An electric-controlled rotary buffer valve for a crane, characterized in that: The invention comprises a main reversing valve (1), one side of the main reversing valve (1) is connected to an oil inlet P and an oil return port R, the oil inlet P is connected to a main overflow valve (2), the other side of the main reversing valve (1) is connected to a working port AM and a working port BM, a secondary overflow valve (5) is arranged between the working port AM and the working port BM and the oil return port R, two control ends of the main reversing valve (1) are connected to an electric proportional pressure reducing valve (6), the control chamber of the secondary overflow valve (5) is connected to a free-swinging solenoid valve (8), and the free-swinging solenoid valve (8) is connected to the oil return port R via an electric proportional overflow valve (9).

2. The electrically controlled rotary buffer valve for a crane according to claim 1, characterized in that: The main reversing valve (1) is a three-position six-way hydraulically controlled reversing valve.

3. The electrically controlled rotary buffer valve for a crane as claimed in claim 2, characterized in that: A sealing steel ball (1-2), a return spring (1-3) and a screw plug (1-4) are symmetrically arranged on the main reversing valve stem (1-1) of the main reversing valve (1), and bypass throttling grooves are arranged adjacent to the middle working position and the left and right working positions of the main reversing valve (1).

4. The electrically controlled rotary buffer valve for a crane according to claim 1, characterized in that: An oil return one-way throttle valve (3) is provided between the main reversing valve (1) and the oil return port R.

5. The electrically controlled rotary buffer valve for a crane as claimed in claim 4, characterized in that: The electric proportional relief valve (9) is connected to an oil return port R via a main reversing valve (1) and an oil return one-way throttle valve (3).

6. The electrically controlled rotary buffer valve for a crane as claimed in claim 4, characterized in that: An oil replenishment check valve (4) is provided between the working port AM and the working port BM and the oil return port R. The oil replenishment check valve (4) is connected to the oil return port R via an oil return check throttle valve (3).

7. The electrically controlled rotary buffer valve for a crane as claimed in claim 1, characterized in that: A control port damper (7) is provided between the electric proportional pressure reducing valve (6) and the control end of the main reversing valve (1).

8. The electrically controlled rotary buffer valve for a crane as claimed in claim 1, characterized in that: A one-way valve is provided between the control chamber of the secondary relief valve (5) and the free-swinging solenoid valve (8).

9. The electrically controlled rotary buffer valve for a crane according to claim 1, characterized in that: The free-swinging solenoid valve (8) is a two-position two-way hydraulically controlled directional valve.

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