Variable amplitude control system

Abstract

The utility model discloses a variable amplitude control system. The problems that an existing amplitude variation system is prone to leakage and poor in safety are solved. The variable-amplitude oil cylinder comprises a variable-amplitude oil cylinder and further comprises an oil tank used for containing oil; the power source is used for conveying oil in the oil tank to the variable-amplitude oil cylinder; the variable-amplitude control valve is arranged between the power source and the variable-amplitude oil cylinder and used for controlling the variable-amplitude oil cylinder to act; the variable-amplitude control valve comprises a first reversing valve, a proportional control valve, a first one-way valve, a second one-way valve, a third one-way valve and a fourth one-way valve. The first reversing valve is provided with a first position and a second position, wherein the first position is opened to facilitate stretching of the variable-amplitude oil cylinder, and the second position is closed to keep the variable-amplitude oil cylinder. The variable-amplitude oil cylinder has the advantages that the first reversing valve, the first one-way valve, the second one-way valve, the third one-way valve and the fourth one-way valve are arranged, so that after the variable-amplitude oil cylinder stretches out, the position can be reliably kept through switching of the first reversing valve, leakage is avoided, and product safety is higher.

Description

Technical Field

[0001] The utility model relates to an engineering machinery luffing system, in particular to a luffing control system. Background Art

[0002] Lifting aerial vehicles, small-tonnage truck cranes and other construction machinery are usually equipped with a luffing system, which is achieved by the extension and retraction of the luffing cylinder. The existing product luffing lowering systems have two luffing lowering modes: gravity lowering and power lowering. These two luffing lowering modes each have their own advantages and disadvantages.

[0003] In the gravity lowering system, the hydraulic pump supplies pressure oil, the solenoid valve is switched, the solenoid valve is in the right position, and after the pressure oil passes through the reversing valve, the one-way valve is opened to enter the rodless chamber of the oil cylinder, so that the oil cylinder moves upward to achieve the lifting of the variable amplitude action; when the solenoid valve is cut off, the oil cylinder can stop at a specified position; when the amplitude is below, the load exerts a force on the oil cylinder due to gravity, and the hydraulic oil in the rodless chamber of the oil cylinder flows back to the oil tank through the solenoid valve to achieve the drop of the variable amplitude cylinder. The advantage of the gravity lowering system is that the drop of the variable amplitude cylinder can be achieved even when the vehicle engine is not started, which effectively reduces energy consumption; at the same time, the gravity lowering of the variable amplitude cylinder is affected by the load. When the load is large, the force exerted by gravity on the variable amplitude cylinder is large, and the drop speed is relatively fast, which poses a safety hazard. When the load is small, the force exerted by gravity on the variable amplitude cylinder is small, and the drop speed will be very slow, resulting in reduced work efficiency. The existing luffing system needs to maintain the luffing extension state after the luffing is extended. The existing hydraulic system often leaks due to the load and the structure of the valve stem after the luffing, which makes the system have great safety hazards. Utility Model Content

[0004] In order to solve the problem that the existing luffing system in the background technology is prone to leakage and has poor safety, the utility model provides a luffing control system.

[0005] The technical solution of the utility model is: a luffing control system, including a luffing oil cylinder, and also including:

[0006] An oil tank, used for containing oil;

[0007] A power source, used to transport the oil in the oil tank to the luffing cylinder;

[0008] The boom control valve is arranged between the power source and the boom cylinder and is used to control the action of the boom cylinder. The boom control valve includes a first reversing valve, a first oil port, a second oil port, a third oil port, and a fourth oil port. A proportional control valve is arranged between the first oil port and the second oil port. A first one-way valve is arranged between the fourth oil port and the first oil port, a second one-way valve is arranged between the second oil port and the fourth oil port, a third one-way valve is arranged between the second oil port and the third oil port, and a fourth one-way valve is arranged between the third oil port and the first oil port. The oil outlet of the power source is connected to the fourth oil port. The third oil port is connected to the rodless cavity of the boom cylinder through the first reversing valve. The first reversing valve has a first position for opening to facilitate the telescoping of the boom cylinder and a second position for closing to hold the boom cylinder.

[0009] As a further improvement of the present utility model, it further includes a one-way throttle valve, and the one-way throttle valve is arranged between the first reversing valve and the rodless cavity of the boom cylinder.

[0010] As a further improvement of the present utility model, the one-way throttle valve includes:

[0011] A fifth one-way valve for supplying oil to the rodless cavity of the boom cylinder when the boom cylinder extends;

[0012] A throttle orifice for the oil in the rodless cavity of the boom cylinder to return when the boom cylinder retracts.

[0013] As a further improvement of the present utility model, the throttle orifice is a fixed damping hole, a variable damping hole, or a cone valve with an adjustable opening size.

[0014] As a further improvement of the present utility model, the proportional control valve includes a proportional spool and a compensating spool. The pressure oil at the first oil port acts on both ends of the proportional spool and causes the proportional spool to slide by electro-hydraulic proportional control.

[0015] As a further improvement of the present utility model, the pressure oil at the first oil port acts on the control cavity of the compensating spool, and the pressure oil at the oil outlet of the proportional spool acts on the spring cavity of the compensating spool and jointly acts with the elastic force in the spring cavity to control the opening of the compensating spool.

[0016] As a further improvement of the present utility model, the proportional control valve is an electro-hydraulic proportional valve with a compensation function.

[0017] As a further improvement of the present utility model, it further includes a second reversing valve. The second reversing valve is arranged between the power source and the third oil port. The second reversing valve has a first position for connecting the power source and the third oil port to communicate for oil supply and a second position for connecting the third oil port and the oil tank to communicate for oil return.

[0018] As a further improvement of the utility model, it also includes an overflow valve, which is arranged between the rodless chamber of the boom cylinder and the oil tank and is used for draining oil from the rodless chamber of the boom cylinder when the load exceeds a safety value.

[0019] As a further improvement of the utility model, the luffing oil cylinder has a rod chamber connected to the oil tank, and the first reversing valve is an electromagnetic reversing valve.

[0020] The beneficial effect of the utility model is that the first reversing valve, the first non-return valve, the second non-return valve, the third non-return valve and the fourth non-return valve are provided, so that after the luffing oil cylinder is extended, the position can be reliably maintained through the switching of the first reversing valve to avoid leakage, making the product safer. The utility model also has the advantages of simple structure, convenient assembly, reliable action and long service life. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Attached Figure 1 It is a schematic diagram of the hydraulic principle of an embodiment of the utility model.

[0022] Attached Figure 2 It is a schematic diagram of the hydraulic principle of the variable amplitude control valve according to an embodiment of the utility model.

[0023] In the figure, 1. luffing cylinder; 11. rodless chamber of luffing cylinder; 12. rod chamber of luffing cylinder; 2. oil tank; 3. power source; 4. luffing control valve; 5. first reversing valve; 6. proportional control valve; 61. proportional valve core; 62. compensation valve core; 7. one-way throttle valve; 71. fifth one-way valve; 72. throttle port; 8. second reversing valve; 9. overflow valve; A1. first oil port; A2. second oil port; A3. third oil port; A4. fourth oil port; D1. first one-way valve; D2. second one-way valve; D3. third one-way valve; D4. fourth one-way valve. DETAILED DESCRIPTION

[0024] The following is a further description of the embodiments of the present invention in conjunction with the accompanying drawings:

[0025] Depend on Figure 1 Combination Figure 2 As shown, a luffing control system includes a luffing cylinder 1, and further includes:

[0026] Oil tank 2, used for containing oil;

[0027] The power source 3 is used to transport the oil in the oil tank 2 to the luffing cylinder 1;

[0028] The boom control valve 4 is arranged between the power source 3 and the boom cylinder 1 and is used to control the operation of the boom cylinder 1. The boom control valve 4 includes a first reversing valve 5, a first oil port A1, a second oil port A2, a third oil port A3, and a fourth oil port A4. A proportional control valve 6 is arranged between the first oil port A1 and the second oil port A2. A first one-way valve D1 is arranged between the fourth oil port A4 and the first oil port A1, a second one-way valve D2 is arranged between the second oil port A2 and the fourth oil port A4, a third one-way valve D3 is arranged between the second oil port A2 and the third oil port A3, and a fourth one-way valve D4 is arranged between the third oil port A3 and the first oil port A1. The oil outlet of the power source 3 is connected to the fourth oil port A4. The third oil port A3 is connected to the rodless cavity 11 of the boom cylinder through the first reversing valve 5. The first reversing valve 5 has a first position that is opened to facilitate the telescopic movement of the boom cylinder 1 and a second position that is closed to hold the boom cylinder 1. The beneficial effect of the present utility model is that the first reversing valve, the first one-way valve, the second one-way valve, the third one-way valve, and the fourth one-way valve are provided, so that after the boom cylinder extends, it can be reliably held in position by switching the first reversing valve, avoiding leakage, and making the product safer. The present utility model also has the advantages of simple structure, convenient assembly, reliable operation, and long service life.

[0029] The present utility model further includes a one-way throttle valve 7, and the one-way throttle valve 7 is arranged between the first reversing valve 5 and the rodless cavity 11 of the boom cylinder. The one-way throttle valve 7 includes:

[0030] A fifth one-way valve 71 for supplying oil to the rodless cavity 11 of the boom cylinder when the boom cylinder 1 extends;

[0031] A throttle orifice 72 for the rodless cavity 11 of the boom cylinder to return oil when the boom cylinder 1 retracts. Specifically, the throttle orifice 72 is a fixed damping hole, a variable damping hole, or a cone valve with an adjustable opening size. In this way, rapid oil supply can be realized, the extension and retraction of the boom cylinder can be achieved with slower speeds, and the safety is higher.

[0032] The proportional control valve 6 includes a proportional valve core 61 and a compensating valve core 62. The pressure oil at the first oil port A1 acts on both ends of the proportional valve core 61 and causes the proportional valve core 61 to slide by electro-proportional control. Specifically, the pressure oil at the first oil port A1 acts on the control chamber of the compensating valve core 62, and the pressure oil at the oil outlet of the proportional valve core 61 acts on the spring chamber of the compensating valve core 62 and jointly acts with the elastic force in the spring chamber to control the opening of the compensating valve core 62. More specifically, the proportional control valve 6 is an electro-proportional valve with a compensation function. Such a structure enables the compensating valve core to achieve dynamic balance. When the load changes, the opening of this compensating valve core changes accordingly, ensuring that the output flow rate only relates to the opening of the proportional valve core.

[0033] The utility model further includes a second reversing valve 8, which is arranged between a power source 3 and a third oil port A3. The second reversing valve 8 has a first position where the power source 3 and the third oil port A3 are connected for oil supply and a second position where the third oil port A3 and the oil tank 2 are connected for oil return. Such a structure can quickly drain oil and has a simple structure.

[0034] The utility model further includes an overflow valve 9, which is arranged between the rodless cavity 11 of the luffing cylinder and the oil tank 2 and is used for draining oil from the rodless cavity 11 of the luffing cylinder when the load exceeds the safety value. The setting of the overflow valve makes the product safer.

[0035] The rod end cavity 12 of the luffing cylinder is connected to the oil tank 2, and the first reversing valve 5 is an electromagnetic reversing valve. When the luffing cylinder of the utility model extends, the rodless cavity faces downward, and the situation of too fast speed will not occur. There can be no oil in the rod end cavity of the luffing cylinder, and the luffing cylinder can be retracted by gravity.

[0036] The following is a further description in combination with the hydraulic schematic diagram:

[0037] 1. Luffing cylinder extension action: The hydraulic oil from the power source (pump) passes through the second reversing valve to port A4, the first check valve D1 to port A1. Due to the action of the check valve, the hydraulic oil can only flow to the proportional reversing valve. By adjusting the proportional reversing current, the opening of the proportional reversing valve (proportional control valve 6) is controlled. The hydraulic oil passes through port A2 and enters the third check valve D3 (at this time, the inlet and outlet pressures of the second check valve D2 are almost the same, and D2 cannot be opened) to A3 (similarly, D4 cannot be opened at this time); the first reversing valve is energized, and the hydraulic oil passes through the first reversing valve and the one-way throttle valve and enters the large cavity of the cylinder, realizing the extension of the cylinder.

[0038] 2. The cylinder maintains the extended state: The first reversing valve is a solenoid valve, and the non-leaking two-way cut-off check valve can ensure that almost no hydraulic oil can pass through the solenoid valve;

[0039] Even if a small amount of hydraulic oil leaks through the first reversing valve to port A3, the third check valve D3 will prevent the hydraulic oil from flowing to the second check valve D2;

[0040] Even if a small amount of hydraulic oil leaks through the first reversing valve to port A1, passes through the fourth check valve D4 to A4, and there is still the protection of the first check valve D1, multiple protections are adopted to keep the cylinder in a certain position without retracting.

[0041] 3. Cylinder retraction: The first reversing valve and the second reversing valve are energized, and the opening of the proportional control valve is adjusted by controlling the current of the proportional control valve; due to the gravity of the cylinder, the hydraulic oil can flow from the one-way throttle valve - the first reversing valve - the fourth check valve - the proportional control valve - the second check valve - the second reversing valve to the oil tank, thereby realizing the retraction of the luffing cylinder.

[0042] 4. The above proportional control valve has a pressure compensation function, which can ensure that the telescopic speed of the oil cylinder is not affected by the load and is only determined by its control current.

[0043] 5. The relief valve has a very small diameter. When the load exceeds the safety value, the hydraulic oil in the large chamber of the oil cylinder slowly drains to the fuel tank through the relief valve, thereby realizing the retraction of the oil cylinder and preventing the luffing oil cylinder from bursting.

[0044] 6. The one-way throttle valve is a one-way valve with a small opening pressure and a large diameter in the extending direction of the luffing oil cylinder; in the retracting direction, it is a damping orifice (throttle orifice) for allowing the hydraulic oil in the large chamber of the oil cylinder to pass through the damping to generate a certain pressure loss, preventing the hydraulic retraction speed of the large chamber of the oil cylinder from being too fast and causing impact on the oil cylinder. It can be a fixed damping orifice or an adjustable cone valve according to different system matches.

[0045] In the description of the present invention, it should be noted that the orientation or positional relationship indicated by the terms "center", "longitudinal", "transverse", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings. It is 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 should not be construed as a limitation to the present invention. In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance.

[0046] In the description of the present invention, it should be noted that unless otherwise clearly specified and defined, the terms "installed", "connected", and "connected" 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 directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations. In addition, in the description of the present invention, unless otherwise stated, the meaning of "a plurality of" is two or more.

[0047] All technicians should note that although the present invention has been described according to the above specific embodiments, the inventive concept of the present invention is not limited to this invention alone. Any modification using the inventive concept of the present invention will be included in the scope of protection of the patent right of the present invention.

Claims

1. A luffing control system, comprising a luffing cylinder (1), characterized in that Also included: An oil tank (2) for containing oil; A power source (3) is used to transport oil in the oil tank (2) to the luffing cylinder (1); The variable amplitude control valve (4) is arranged between the power source (3) and the variable amplitude cylinder (1) and is used to control the movement of the variable amplitude cylinder (1); the variable amplitude control valve (4) comprises a first reversing valve (5), a first oil port (A1), a second oil port (A2), a third oil port (A3) and a fourth oil port (A4); a proportional control valve (6) is arranged between the first oil port (A1) and the second oil port (A2); a first non-return valve (D1) is arranged between the fourth oil port (A4) and the first oil port (A1); a first non-return valve (D1) is arranged between the second oil port (A2) and the fourth oil port (A4); A second one-way valve (D2) is provided between the second oil port (A2) and the third oil port (A3), a third one-way valve (D3) is provided between the second oil port (A2) and the third oil port (A3), a fourth one-way valve (D4) is provided between the third oil port (A3) and the first oil port (A1), the oil outlet of the power source (3) is connected to the fourth oil port (A4), the third oil port (A3) is connected to the rodless chamber (11) of the boom cylinder through a first reversing valve (5), and the first reversing valve (5) has a first position of opening to facilitate the extension and retraction of the boom cylinder (1) and a second position of closing to maintain the boom cylinder (1).

2. A variable amplitude control system according to claim 1, characterized in that It also includes a one-way throttle valve (7), which is arranged between the first reversing valve (5) and the rodless chamber (11) of the variable amplitude oil cylinder.

3. A variable amplitude control system according to claim 2, characterized in that The one-way throttle valve (7) comprises: A fifth one-way valve (71) is used to supply oil to the rodless chamber (11) of the luffing oil cylinder when the luffing oil cylinder (1) is extended; The throttle port (72) is used to return oil from the rodless chamber (11) of the luffing cylinder when the luffing cylinder (1) is retracted.

4. A variable amplitude control system according to claim 3, characterized in that The throttle opening (72) is a fixed damping hole, a variable damping hole, or a cone valve with an adjustable opening size.

5. A variable amplitude control system according to claim 1, characterized in that The proportional control valve (6) comprises a proportional valve core (61) and a compensation valve core (62), and the pressure oil of the first oil port (A1) acts on both ends of the proportional valve core (61) to cause the proportional valve core (61) to slide under electric proportional control.

6. A variable amplitude control system according to claim 1, characterized in that The pressure oil of the first oil port (A1) acts on the control chamber of the compensation valve core (62), and the pressure oil of the oil outlet of the proportional valve core (61) acts on the spring chamber of the compensation valve core (62) and acts together with the elastic force in the spring chamber to control the opening of the compensation valve core (62).

7. A variable amplitude control system according to claim 1, characterized in that The proportional control valve (6) is an electric proportional valve with a compensation function.

8. A variable amplitude control system according to claim 1, characterized in that The invention also comprises a second reversing valve (8), the second reversing valve (8) being arranged between the power source (3) and the third oil port (A3), the second reversing valve (8) having a first position in which the power source (3) and the third oil port (A3) are connected for oil supply, and a second position in which the third oil port (A3) and the oil tank (2) are connected for oil return.

9. A variable amplitude control system according to claim 1, characterized in that It also includes a relief valve (9), which is arranged between the rodless chamber (11) of the luffing oil cylinder and the oil tank (2) and is used to drain oil from the rodless chamber (11) of the luffing oil cylinder when the load exceeds a safety value.

10. A variable amplitude control system according to claim 1, characterized in that The variable amplitude oil cylinder has a rod chamber (12) which is connected to the oil tank (2), and the first reversing valve (5) is an electromagnetic reversing valve.

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