A loader lifting and anti-spreading control system and method

Abstract

A loader lifting anti-spill control system and method includes a bucket, a boom, and a bucket cylinder connected to the bucket, wherein the bucket cylinder is connected to a variable pump via a main valve, the main valve is connected to a pilot control device, the main valve is connected to an oil tank via a second relief valve and a third relief valve, the variable pump is connected to a pump displacement control device, and the variable pump is also connected to a valve group control system of the boom; further comprising a controller, wherein the input end of the controller is connected to a handle, a boom angle sensor, and a bucket angle sensor, and the output end of the controller is connected to a pilot control device and a pump displacement control device. The loader lifting anti-spill control system and method of the present invention allows the bucket side blade to gradually become parallel to the ground angle during the lifting process, that is, the bucket side blade is in a horizontal position in the second half of the lifting period, eliminating the angle difference, thereby solving the problem of a large amount of material spilling; during the lifting process, no material is spilled, more material can be loaded and unloaded, and the productivity of a single cycle operation is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of engineering machinery, and in particular to a loader lifting and anti-scattering control system and method. Background Art

[0002] In the prior art, after the bucket is retracted, a lot of material is spilled during the lifting process. When the bucket side blade is lifted to a high position, the angle difference with the ground is about 6-10 degrees. This difference causes the bucket side blade to be not flat when the bucket is at the highest position. That is, from a distance, the bucket is generally tilted forward. After the lifting is suddenly stopped, the angle difference will cause a lot of material to spill instantaneously.

[0003] The comparative document "CN112523286A, A Method and System for Automatic Adjustment and Control of Horizontal Lifting of a Loader," offers the beneficial effect of maintaining the bucket's horizontal position throughout its movement from the ground to its highest raised position. This addresses the technical issue of the bucket's inability to remain horizontal during lifting. However, this technical solution does not prevent material spillage.

[0004] The present invention provides a loader lifting anti-scattering control system, which allows the bucket side blades to gradually become parallel to the ground during the lifting process, that is, the bucket side blades are in a horizontal position in the second half of the lifting, eliminating the angle difference, thereby solving the problem of more material spilling. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to overcome the deficiencies of the above-mentioned prior art and provide a loader lifting and anti-spreading control system and method.

[0006] The present invention is implemented by the following technical solution: a loader lifting and anti-spreading control system, comprising a bucket, a boom, and a bucket cylinder connected to the bucket, the bucket cylinder being connected to a variable pump via a main valve, the main valve being connected to a pilot control device, the large chamber and small chamber of the main valve being connected to a fuel tank via a second relief valve and a third relief valve, respectively, the variable pump being connected to a pump displacement control device, and the variable pump being further connected to a valve group control system of the boom;

[0007] It also includes a controller, wherein the input end of the controller is connected to the handle, the boom angle sensor and the bucket angle sensor, and the output end of the controller is connected to the pilot control device and the pump displacement control device;

[0008] The controller adjusts the angle of the bucket side blade in real time according to the boom lifting angle. When the boom angle is raised from the initial position to the extended position, the angle of the bucket side blade decreases from the initial position to the horizontal position. When the boom continues to be raised from the extended position to the highest position, the angle of the bucket side blade always remains horizontal.

[0009] It is further provided that: the main valve is a three-position four-way hydraulically controlled spring-reset proportional valve.

[0010] The pilot control device includes a second solenoid valve, a third solenoid valve and a sixth solenoid valve. The input end of the second solenoid valve is connected to the variable pump through a pressure reducing valve, and the output end of the second solenoid valve is connected to the input ends of the third solenoid valve and the sixth solenoid valve. The output ends of the third solenoid valve and the sixth solenoid valve are respectively connected to the two control ends of the main valve. The input end of the second solenoid valve is also connected to the oil tank through a pilot overflow valve.

[0011] The second solenoid valve, the third solenoid valve and the sixth solenoid valve are two-position three-way proportional solenoid valves, and the control ends of the second solenoid valve, the third solenoid valve and the sixth solenoid valve are connected to a controller.

[0012] The two output ends of the main valve are connected to the fifth solenoid valve and the fourth solenoid valve respectively. The small chamber of the bucket cylinder is connected to the main valve via the fifth solenoid valve, and the large chamber of the bucket cylinder is connected to the main valve via the fourth solenoid valve.

[0013] The fifth solenoid valve and the fourth solenoid valve are two-position, two-way solenoid valves with spring return, and the control ends of the fifth solenoid valve and the fourth solenoid valve are connected to a controller.

[0014] The pump displacement control device includes a control cylinder and a first solenoid valve. The control cylinder is connected to the control end of the variable pump, the input end of the first solenoid valve is connected to the output end of the variable pump, the output end of the first solenoid valve is connected to the large and small chambers of the control cylinder, a first overflow valve is provided between the input end of the first solenoid valve and the oil tank, and a throttle valve is provided between the oil outlet end of the first solenoid valve and the oil tank.

[0015] The first solenoid valve is a three-position four-way proportional solenoid valve with spring return, and two control ends of the first solenoid valve are connected to a controller.

[0016] A method for using a loader lifting and anti-spreading control system, wherein the steps for lifting the boom are as follows:

[0017] S1. The driver moves the handle toward the boom raising position;

[0018] S2, the controller inputs an electrical signal to the control terminals of the first solenoid valve, the second solenoid valve, the sixth solenoid valve, the fourth solenoid valve, and the fifth solenoid valve, so that oil flows into the small chambers of the control cylinder and the bucket cylinder;

[0019] S3. As the boom lifting angle increases, the bucket cylinder moves dynamically. The boom angle sensor and bucket angle sensor input angle signals to the controller. The controller controls the control cylinder and bucket cylinder according to the preset boom angle and bucket angle relationship, and then adjusts the bucket angle according to the boom angle.

[0020] S4. When the lifting is completed, the driver releases the handle, and the handle returns to the position where the boom is raised;

[0021] S5, the controller inputs a 0 electrical signal to the control terminals of the second, sixth, fourth, and fifth solenoid valves, locking the piston rod of the bucket cylinder in the current position, and inputs a control signal to the first solenoid valve to control the piston rod of the control cylinder to extend, thereby reducing the displacement of the variable displacement pump;

[0022] S6. When the displacement of the variable pump is 0, the controller inputs a 0 electrical signal to the control end of the first solenoid valve, the first solenoid valve, the boom valve group control system flow is 0, the boom lifting valve group is closed, and the boom stops lifting.

[0023] The relationship between the boom angle and the bucket angle is that when the boom is raised from the ground bucket retracted position, the angle of the bucket side blade decreases as the boom angle increases. When the boom angle increases from a negative angle to 0 degrees, the angle of the bucket side blade decreases to 0 degrees. When the boom angle continues to increase from 0 degrees to the highest position, the angle of the bucket side blade remains at 0 degrees.

[0024] The present invention has the following advantages: the loader lifting anti-scattering control system and method of the present invention allows the bucket side blade to gradually become parallel to the ground during the lifting process, that is, the bucket side blade is in a horizontal position in the second half of the lifting, eliminating the angle difference, thereby solving the problem of more material spilling; during the lifting process, no material is spilled, more material can be loaded and unloaded, and the productivity of a single cycle operation is improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The accompanying drawings, as part of this disclosure, are intended to provide a further understanding of the disclosure. The exemplary embodiments of the disclosure and their descriptions are intended to explain the disclosure and do not constitute undue limitations thereon. Obviously, the drawings described below are merely examples, and those skilled in the art can derive other drawings based on these drawings without inventive effort.

[0026] Figure 1 It is the hydraulic principle diagram of the present invention;

[0027] Figure 2 This is a hydraulic principle diagram of the bucket cylinder extension action of the present invention;

[0028] Figure 3 This is a schematic diagram of the loader of the present invention in a flat ground position;

[0029] Figure 4 This is a schematic diagram of the loader of the present invention in a bucket-folding state;

[0030] Figure 5It is a schematic diagram of the bucket being lifted from the retracted position to the extended position in the prior art;

[0031] Figure 6 This is a schematic diagram of the bucket being lifted from the retracted state to the highest position in the prior art;

[0032] Figure 7 It is a schematic diagram of the bucket of the present invention being lifted from a retracted state to an extended position;

[0033] Figure 8 It is a schematic diagram of the bucket of the present invention being lifted from the retracted state to the highest position;

[0034] Figure 9 It is a graph showing the relationship between the boom angle and the bucket angle during the process of lifting the bucket from the retracted position;

[0035] Figure 10 It is a schematic diagram of the change in the extension or retraction of the bucket cylinder as the boom lifting time changes.

[0036] Among them, 1. Handle, 2. Fuel tank, 3. Controller, 4. Boom angle sensor, 5. Bucket angle sensor, 6. Throttle valve, 7. Control cylinder, 8. First relief valve, 9. First solenoid valve, 10. Second solenoid valve, 11. Third solenoid valve, 12. Fourth solenoid valve, 13. Second relief valve, 14. Tipping cylinder, 15. Third relief valve, 16. Fifth solenoid valve, 17. Main valve, 18. Sixth solenoid valve, 19. Pressure reducing valve, 20. Pilot relief valve, 21. Variable pump.

[0037] It should be noted that these drawings and textual descriptions are not intended to limit the conceptual scope of the present invention in any way, but rather to illustrate the concept of the present invention for those skilled in the art by referring to specific embodiments. Implementation Method

[0038] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. The following embodiments are used to illustrate the present invention but are not used to limit the scope of the present invention.

[0039] In the description of the present invention, it should be noted that the terms "upper", "lower", "front", "back", "left", "right", "vertical", "inside", "outside", etc., indicating directions or positional relationships, are based on the directions or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction. Therefore, they cannot be understood as limiting the present invention.

[0040] In the description of the present invention, it should be noted that, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "connected" should be understood broadly. For example, they may refer to fixed, detachable, or integral connections; mechanical or electrical connections; and direct or indirect connections through an intermediary. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on the specific circumstances.

[0041] like Figures 1 to 3 The loader lifting and anti-spill control system shown in the figure includes a bucket, a boom, and a bucket cylinder 14 connected to the bucket. The bucket cylinder 14 is connected to a variable pump 21 through a main valve 17. The main valve 17 is connected to a pilot control device. The large chamber and small chamber of the main valve 17 are connected to the oil tank 2 through a second relief valve 13 and a third relief valve 15, respectively. The variable pump 21 is connected to a pump displacement control device. The variable pump 21 is also connected to the valve group control system of the boom; and also includes a controller 3. The input end of the controller 3 is connected to a handle 1, a boom angle sensor 4 and a bucket angle sensor 5. The output end of the controller 3 is connected to the pilot control device and the pump displacement control device. The controller adjusts the angle of the bucket side blade in real time according to the boom lifting angle. When the boom angle is raised from the initial position to the extended position, the angle of the bucket side blade decreases from the initial position to the horizontal position. When the boom continues to be raised from the extended position to the highest position, the angle of the bucket side blade always remains horizontal. The loader lifting and anti-spreading control system of the present invention includes a variable pump 21, a pump displacement control device, a main valve 17, a pilot control device, a bucket cylinder 14, a handle 1, a controller 3, a sensor 4 for detecting the boom angle, and a sensor 5 for detecting the bucket angle; wherein, the variable pump supplies oil to the bucket cylinder and the boom valve group control system, the pump displacement control device is used to control the displacement of the variable pump, the main valve is used to control the oil inlet direction and size of the bucket cylinder, the pilot control device is used to control the opening and closing of the main valve and the opening size, the pump displacement control device and the pilot control device can be either an electronic control device or a hydraulic control device, and their actions are controlled by the controller; the controller outputs corresponding electrical signals according to the handle signal to control the actions of the pump displacement control device and the pilot control device, the boom angle sensor 4 and the bucket angle sensor 5 input the angle information of the boom and bucket into the controller in real time, so as to facilitate real-time adjustment of the bucket angle.

[0042] like Figures 1 to 2The illustrated control system for lifting and preventing material spillage on a loader features a main valve 17, a three-position, four-way hydraulically controlled, spring-return proportional valve. In the main oil circuit of the present invention, hydraulic oil is connected to port P of the main valve 17 via a variable pump 21. Port A of the main valve 17 is connected to port C of the fifth solenoid valve 16, and port D of the fifth solenoid valve 16 is connected to port G1 of the bucket cylinder 14. Port G2 of the bucket cylinder 14 is connected to port F of the fourth solenoid valve 12, and port E of the fourth solenoid valve 12 is connected to port B of the main valve 17. Port T of the main valve 17 is connected to the fuel tank 2. Alternatively, port G1 of the bucket cylinder 14 returns to the fuel tank 2 via the third relief valve 15. Alternatively, port G2 of the bucket cylinder 14 returns to the fuel tank 2 via the second relief valve 13.

[0043] like Figures 1 to 2 The illustrated loader lifting and anti-spill control system comprises a pilot control device comprising a second solenoid valve 10, a third solenoid valve 11, and a sixth solenoid valve 18. The input of the second solenoid valve 10 is connected to a variable pump 21 via a pressure reducing valve 19, while the output of the second solenoid valve 10 is connected to the inputs of the third and sixth solenoid valves 11, 18. The outputs of the third and sixth solenoid valves 11, 18 are respectively connected to the two control terminals of a main valve 17. The input of the second solenoid valve 10 is also connected to a fuel tank 2 via a pilot relief valve 20. The second, third, and sixth solenoid valves 10, 11, 18 are two-position, three-way proportional solenoid valves, and their control terminals are connected to a controller 3. The pilot control device of the present invention adopts a hydraulic control device, which specifically includes a second solenoid valve 10, a third solenoid valve 11 and a sixth solenoid valve 18. In the pilot control oil circuit, the outlet of the variable pump 21 is connected to the pressure reducing valve 19, and the outlet of the pressure reducing valve 19 is simultaneously connected to the pilot relief valve 20 and the V1 port of the second solenoid valve 10, wherein the X1 port of the second solenoid valve 10 is simultaneously connected to the Q2 port of the third solenoid valve 11 and the Q1 port of the sixth solenoid valve 18, the S2 port of the third solenoid valve 11 is connected to the U2 port of the main valve 17, and the S1 port of the sixth solenoid valve 18 is connected to the U1 port of the main valve 17, and the outlet of the pilot relief valve 20, the W1 port of the second solenoid valve 10, the R2 port of the third solenoid valve 11 and the R1 port of the sixth solenoid valve 18 are simultaneously connected to the oil tank 2.

[0044] like Figures 1 to 2In the illustrated embodiment of a loader lifting and anti-spill control system, the two output ends of the main valve 17 are connected to the fifth solenoid valve 16 and the fourth solenoid valve 12, respectively. The small chamber of the bucket cylinder 14 is connected to the main valve 17 via the fifth solenoid valve 16, and the large chamber of the bucket cylinder 14 is connected to the main valve 17 via the fourth solenoid valve 12. The fifth solenoid valve 16 and the fourth solenoid valve 12 are two-position, two-way solenoid valves with spring return. The control ends of the fifth solenoid valve 16 and the fourth solenoid valve 12 are connected to the controller 3. The current outputted by the controller 3 to the fourth solenoid valve 12 and the fifth solenoid valve 16 is a constant value greater than 0 or 0, which is a switching signal; while the current outputted to the remaining solenoid valves is a variable linear value or 0, which is an analog signal.

[0045] like Figures 1 to 2 The illustrated embodiment of a loader lifting and anti-spill control system includes a pump displacement control device comprising a control cylinder 7 and a first solenoid valve 9. The control cylinder 7 is connected to the control end of a variable displacement pump 21. The input end of the first solenoid valve 9 is connected to the output end of the variable displacement pump 21, and the output end of the first solenoid valve 9 is connected to the large and small chambers of the control cylinder 7. A first relief valve 8 is provided between the input end of the first solenoid valve 9 and the fuel tank 2, and a throttle valve 6 is provided between the oil outlet end of the first solenoid valve 9 and the fuel tank 2. The first solenoid valve 9 is a three-position, four-way, spring-return proportional solenoid valve. Both control ends of the first solenoid valve 9 are connected to a controller 3. The pump displacement control device of the present invention utilizes a hydraulic control device. In the pump displacement control oil circuit, the outlet of the variable displacement pump 21 is connected to port H of the first solenoid valve 9 and the first relief valve 8. Port K of the first solenoid valve 9 is connected to port M of the control cylinder 7, port L of the first solenoid valve 9 is connected to port N of the control cylinder 7, port J of the first solenoid valve 9 is connected to the fuel tank 2 via the throttle valve 6, and the outlet of the first relief valve 8 is connected to the fuel tank 2.

[0046] A method for using a loader lifting and anti-spreading control system, such as Figure 3-4 、 Figure 7-Figure 8 As shown, the steps for lifting the boom are as follows:

[0047] S1, the driver moves handle 1 to the lifting position at an angle;

[0048] S2, the controller 3 inputs an electrical signal to the control ends of the first solenoid valve 9, the second solenoid valve 10, the sixth solenoid valve 18, the fourth solenoid valve 12 and the fifth solenoid valve 16, so that oil flows into the small chamber of the control cylinder 7 and the small chamber of the bucket cylinder 14;

[0049] S3. As the boom lifting angle increases, the bucket cylinder moves dynamically. The boom angle sensor 4 and the bucket angle sensor 5 input angle signals to the controller 3. The controller 3 controls the control cylinder 7 and the bucket cylinder 14 according to the preset boom angle and bucket angle relationship, and then adjusts the bucket angle according to the boom angle.

[0050] S4. When the lifting is completed, the driver releases the handle 1, and the handle 1 returns to the position where the boom is raised;

[0051] S5: The controller 3 inputs a 0 electrical signal to the control terminals of the second solenoid valve 10, the sixth solenoid valve 18, the fourth solenoid valve 12, and the fifth solenoid valve 16, so that the piston rod of the bucket cylinder 14 is locked in the current position. The controller 3 inputs a control signal to the first solenoid valve 9 to control the piston rod of the control cylinder 7 to extend, thereby reducing the displacement of the variable pump 21.

[0052] S6. When the displacement of the variable pump 21 is 0, the controller 3 inputs a 0 electrical signal to the control end of the first solenoid valve 9. The first solenoid valve 9 and the boom valve group control system flow are 0, the boom lifting valve group is closed, and the boom stops lifting.

[0053] Figure 9-10 As shown, the relationship between the boom angle and bucket angle is as follows: when the boom is raised from the ground-stowed position, the bucket blade angle decreases as the boom angle increases. When the boom angle increases from a negative angle to 0 degrees, the bucket blade angle decreases to 0 degrees. When the boom angle continues to increase from 0 degrees to the highest position, the bucket blade angle remains at 0 degrees. When the boom angle is at the ground-stowed position, the initial boom angle is (-37° to -39°); the initial bucket blade angle is (26° to 27°). Figure 9 Curve 1 in the figure is the angle change curve between the bucket side blade and the ground in the prior art. The lifting process is Figure 4-5 -6, a total of 8 seconds. During this process, the bucket cylinder remains stationary, so the angle of the bucket side blade cannot be dynamically adjusted; Curve 2 is the technical solution of the present invention, the angle change curve of the bucket side blade and the ground, the lifting process is Figure 4-7 -8, a total of 8 seconds. During this process, the bucket cylinder maintains dynamic adjustment action to maintain the curve effect; Curve 3 is the angle change curve of the boom, that is, the angle between the line connecting the front hinge point and the rear hinge point of the boom and the ground changes with the lifting time. When the boom angle is 0 (that is, at 4.5 seconds), the angle of the bucket side blade is also 0, that is, when the boom is extended, the bucket side blade remains horizontal. After 4.5 seconds, the boom angle continues to increase, while the angle of the bucket side blade remains at 0°, that is, the bucket side blade remains horizontal. Figure 10In the figure, time t0 refers to the time when the bucket begins to raise the boom from the ground, when the bucket side blade's initial angle (26.5°) decreases with the lifting time, reaching the inflection point of 0°. From t0 onward, the bucket cylinder begins to extend; before t0, the bucket cylinder is retracted. The controller dynamically adjusts the extension or retraction of the bucket cylinder based on the boom lift angle, ensuring that the bucket side blade angle follows Curve 2, thus preventing material from spilling when the bucket is raised to its highest position.

[0054] The anti-scattering control principle of the present invention is as follows:

[0055] like Figure 1 、 Figure 4 、 Figure 7 and Figure 8 As shown, in the ground bucket position ( Figure 4 ), the driver turns the handle 1 downwards to an angle, and the boom starts to lift. During the lifting process, if the controller 3 does not control the bucket cylinder, the angle of the bucket side blade changes according to Figure 9 The angle of the bucket side blade of the present invention changes according to the curve 1 in the prior art. Figure 9 Curve 2 in FIG is performed, and the angle of the bucket side blade responds one-to-one with the change of the boom angle. That is, curve 2 and curve 3 correspond to each other. Therefore, the controller 3 outputs current signals to terminal b7 of the first solenoid valve 9, terminal b2 of the second solenoid valve 10, and terminal b6 of the sixth solenoid valve 18, and outputs constant current signals to terminal b4 of the fourth solenoid valve 12 and terminal b5 of the fifth solenoid valve 16. At this time:

[0056] Pump displacement control oil circuit:

[0057] The H port and K port of the first solenoid valve 9 are connected, and the J port and L port are connected. The hydraulic oil enters the small chamber of the control cylinder 7 through the variable pump 21, the H port and K port of the first solenoid valve 9, and the M port of the control cylinder 7, pushing the piston rod to the right, changing the inclination angle of the pump swash plate. The hydraulic oil in the large chamber of the control cylinder 7 is returned through the N port, L port, J port and the throttle valve 6.

[0058] Pilot control oil circuit:

[0059] The V1 port and X1 port of the second solenoid valve 10 are connected, and the S1 port and Q1 port of the sixth solenoid valve 18 are connected; the pilot oil passes through the variable pump 21, the pressure reducing valve 19, the V1 port and X1 port of the second solenoid valve 10, the Q1 port and S1 port of the sixth solenoid valve 18, to the U1 port of the main valve 17, pushing the valve core of the main valve 17 to the right position, and then the P port and A port of the main valve 17 are connected, and the B port and T port are connected; the control oil at the other end of the main valve 17 returns to the oil tank 2 through the U2 port, the S2 port and R2 port of the third solenoid valve 11.

[0060] Main oil circuit:

[0061] The hydraulic oil is connected to the control circuit of the boom lifting valve group through the variable pump 21 and P2 port, and the boom starts to lift.

[0062] The F port and E port of the fourth solenoid valve 12 are fully connected, the D port and C port of the fifth solenoid valve 16 are fully connected, the P port and A port of the main valve 17 are connected, and the B port and T port are connected. The hydraulic oil passes through the variable pump 21, the P port and A port of the main valve 17, the C port and D port of the fifth solenoid valve 16, and the G1 port of the bucket cylinder 14 to the small chamber of the bucket cylinder 14, pushing the piston rod of the bucket cylinder 14 to retract to the right, and the large chamber of the bucket cylinder returns oil through the G2 port, the F port and E port of the fourth solenoid valve 12, and the B port and T port of the main valve 17, thereby realizing the bucket retraction and dynamically adjusting the angle of the bucket side blade.

[0063] The pressure reducing valve 19 is mainly used to ensure that the pilot pressure meets the requirements of the pilot oil circuit. It is a fixed-value pressure reducing valve, that is, the pressure of the pilot oil circuit is a constant value. Preferably, the pilot pressure is 2 MPa.

[0064] The pilot relief valve 20 is used to ensure that the maximum value of the pilot pressure does not exceed a set value; preferably, the maximum value of the pilot pressure is 2.5 MPa.

[0065] The first relief valve 8 is used to ensure that the maximum pressure of the variable pump 21 does not exceed a set value. Preferably, the set value is 35 MPa.

[0066] The second relief valve 13 and the third relief valve 15 are used to ensure that the pressure in the large chamber and the small chamber of the hoist cylinder does not exceed a set value, respectively; preferably, the set value is 30 MPa.

[0067] The second solenoid valve 10, the third solenoid valve 11 and the sixth solenoid valve 18 are all two-position three-way proportional solenoid valves; the fourth solenoid valve 12 and the fifth solenoid valve 16 are two-position two-way solenoid valves with spring return; the first solenoid valve 9 is a three-position four-way proportional solenoid valve with spring return; the main valve 17 is a three-position four-way hydraulically controlled spring-return proportional valve.

[0068] As the boom lifting angle increases, the bucket cylinder moves dynamically and the angle of the bucket side blade continues to decrease. When it is lifted to the horizontal position, Figure 5 , that is, when the line connecting the front hinge point and the rear hinge point of the boom is parallel to the ground, the angle of the bucket side blade is 0, parallel to the ground, corresponding to Figure 9The inflection point of curve 2 in the figure is at 4.5. The boom continues to rise, but the bucket blades remain at zero angle, parallel to the ground, until the lift is complete. Because the bucket blades remain horizontal, material is prevented from spilling at the highest position and during the lift, resulting in high loading and unloading efficiency and increased productivity per load and unload. This also prevents material (gravel, rock, coal, etc.) dropped from the bucket from impacting the cylinder and structural components, improving the reliability of the working device.

[0069] When the lifting is completed, the driver releases the handle, and the handle returns to the position where the boom is raised. The controller 3 outputs a 0 current signal to the b7 terminal of the first solenoid valve 9, the b2 terminal of the second solenoid valve 10, and the b6 terminal of the sixth solenoid valve 18, outputs a 0 current signal to the b4 terminal of the fourth solenoid valve 12 and the b5 terminal of the fifth solenoid valve 16, and outputs a current signal to the b1 terminal of the first solenoid valve 9. At this time:

[0070] Pump displacement control oil circuit: Ports H and L of the first solenoid valve 9 are connected, and ports J and K are connected; hydraulic oil enters the large chamber of the control cylinder through the variable pump 21, ports H and L of the first solenoid valve 9, and port N of the control cylinder 7, pushing the piston rod to the left, reducing the pump swash plate angle to zero, and thus controlling the pump output displacement to zero. The hydraulic oil in the small chamber of the control cylinder 7 returns through ports M, K, and J, as well as the throttle valve 6.

[0071] When the pump displacement is 0, the b1 terminal of the first solenoid valve 9 outputs a 0 current signal, and the solenoid valve is reset. The flow rate of the P2 port is 0, the boom lifting valve group is closed, and the boom stops lifting.

[0072] Pilot control oil circuit: Ports V1 and W1 of the second solenoid valve 10 are connected; ports S1 and R1 of the sixth solenoid valve 18 are connected; the pilot oil returns through the variable pump 21, the pressure reducing valve 19, and ports V1 and W1 of the second solenoid valve 10;

[0073] The pilot oil on the left side of the main valve 17 returns through the U1 port, the S1 port and the R1 port of the sixth solenoid valve 18, and the main valve spool automatically resets until the P port and the A port of the main valve 17 are cut off, and the B port and the T port are cut off;

[0074] Main oil circuit: Ports F and E of the fourth solenoid valve 12 are completely blocked, ports D and C of the fifth solenoid valve 16 are completely blocked, and the piston rod of the bucket cylinder 14 is locked in the current position.

[0075] It should be noted that:

[0076] 1. The handle 1 can move in four directions, controlling the bucket left and right, and controlling the boom lifting up and down; and the four actions are mutually exclusive. At any one time, the handle can only have one position, that is, the handle cannot control the bucket while it is being lifted. The technical solution of the present invention is that when the handle controls the boom lifting, the controller automatically controls the bucket movement, thereby adjusting the angle of the bucket side blade.

[0077] 2. In the prior art, the angle of the bucket refers to the angle between the main blade or bottom plate of the bucket and the ground (such as Figure 4 The angle of the bucket side blade of the present invention refers to the angle between the upper edge of the bucket side blade and the ground.

[0078] 3. Before the inflection point of Curve 2 appears, that is, before the angle of the bucket side blade drops to 0°, the controller controls the bucket cylinder to retract; after the inflection point of Curve 2 appears, that is, when the angle of the bucket side blade remains at 0°, the controller controls the bucket cylinder to extend; the extension of the bucket cylinder is opposite to the oil circuit control principle of the retraction action. That is, the controller controls the angle of the bucket side blade and performs real-time feedback adjustment to meet the requirements of Curve 2. The program set by the controller of the present invention can be set according to the correspondence between Curve 3 and Curve 2, that is, different boom angles correspond to the angle of the bucket side blade, to ensure that the response of the bucket cylinder meets the changing requirements of Curve 2.

[0079] 4. If, after the inflection point of Curve 2 appears, that is, when the bucket blades remain horizontal, the controller stops controlling the bucket cylinder and the bucket cylinder becomes locked, then as the boom continues to rise, the bucket blade angle will decrease below zero and continue to decrease, causing more material to be spread. Therefore, after the inflection point of Curve 2 appears, the controller will control the bucket cylinder to extend to maintain the bucket blade angle horizontal.

[0080] The loader lifting and anti-spill control system and method of the present invention, during the process of the bucket lifting the boom from the ground bucket-retracted state, the controller adjusts the inlet and return oil of the dump cylinder according to the change of the boom angle, and then controls the angle of the bucket side blade relative to the ground to respond according to a preset curve, that is, before the boom is in the horizontally extended position, the angle of the bucket side blade decreases as the boom lifting angle increases; in the boom horizontally extended position and after the horizontally extended position, the angle of the bucket side blade remains horizontal; when the boom is in the horizontally extended position, the angle of the bucket side blade remains parallel to the ground, and during the process of lifting from the horizontally extended position to the highest position, the bucket side blade always remains in the horizontal position. The controller dynamically adjusts the extension and retraction of the dump cylinder by controlling the variable pump and various solenoid valves, so as to achieve the effect of preventing the bucket material from spilling when in the high position, thereby achieving higher comprehensive productivity, and at the same time effectively preventing the spilled material from impacting the oil cylinder, structural parts, etc., thereby improving the reliability of the working device.

[0081] In the description provided herein, numerous specific details are described. However, it is understood that embodiments of the present invention may be practiced without these specific details. In some instances, well-known methods, structures, and techniques are not shown in detail so as not to obscure the understanding of this description.

[0082] Furthermore, those skilled in the art will appreciate that, although some embodiments described herein include certain features included in other embodiments but not other features, combinations of features from different embodiments are also intended to fall within the scope of protection of the present invention and form different embodiments. For example, in the above embodiments, those skilled in the art will be able to use them in combination based on the known technical solutions and the technical problems to be solved by this application.

[0083] The above description is merely a preferred embodiment of the present invention and does not constitute any form of limitation to the present invention. Although the present invention has been disclosed as above in terms of a preferred embodiment, it is not intended to limit the present invention. Any technician familiar with this patent can make slight changes or modifications to equivalent embodiments using the above-mentioned technical contents without departing from the scope of the technical solution of the present invention. However, any simple modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention are still within the scope of the solution of the present invention.

Claims

1. A loader lifting and anti-spreading control system, characterized by: The invention comprises a bucket, a boom, and a bucket cylinder (14) connected to the bucket, wherein the bucket cylinder (14) is connected to a variable pump (21) via a main valve (17), the main valve (17) is connected to a pilot control device, the large chamber and the small chamber of the bucket cylinder (14) are connected to an oil tank (2) via a second relief valve (13) and a third relief valve (15), respectively, the variable pump (21) is connected to a pump displacement control device, and the variable pump (21) is also connected to a valve group control system of the boom; It also includes a controller (3), the input end of the controller (3) is connected to the handle (1), the boom angle sensor (4) and the bucket angle sensor (5), and the output end of the controller (3) is connected to the pilot control device and the pump displacement control device; The controller adjusts the angle of the bucket side blade in real time according to the boom lifting angle. When the boom angle is raised from the initial position to the extended position, the angle of the bucket side blade decreases from the initial position to the horizontal position. When the boom continues to be raised from the extended position to the highest position, the angle of the bucket side blade always remains horizontal. The main valve (17) is a three-position four-way hydraulically controlled spring-return proportional valve; The pilot control device comprises a second solenoid valve (10), a third solenoid valve (11) and a sixth solenoid valve (18), wherein the input end of the second solenoid valve (10) is connected to the variable pump (21) via a pressure reducing valve (19), the output end of the second solenoid valve (10) is connected to the input ends of the third solenoid valve (11) and the sixth solenoid valve (18), the output ends of the third solenoid valve (11) and the sixth solenoid valve (18) are respectively connected to the two control ends of the main valve (17), and the input end of the second solenoid valve (10) is also connected to the oil tank (2) via a pilot overflow valve (20).

2. A loader lifting and anti-spreading control system according to claim 1, characterized in that: The second solenoid valve (10), the third solenoid valve (11) and the sixth solenoid valve (18) are two-position three-way proportional solenoid valves, and the control ends of the second solenoid valve (10), the third solenoid valve (11) and the sixth solenoid valve (18) are connected to the controller (3).

3. The loader lifting and anti-spreading control system according to claim 1, characterized in that: The two output ends of the main valve (17) are respectively connected to the fifth solenoid valve (16) and the fourth solenoid valve (12); the small cavity of the bucket cylinder (14) is connected to the main valve (17) via the fifth solenoid valve (16); and the large cavity of the bucket cylinder (14) is connected to the main valve (17) via the fourth solenoid valve (12).

4. A loader lifting and anti-spreading control system according to claim 3, characterized in that: The fifth solenoid valve (16) and the fourth solenoid valve (12) are two-position, two-way solenoid valves with spring reset, and the control ends of the fifth solenoid valve (16) and the fourth solenoid valve (12) are connected to the controller (3).

5. The loader lifting and anti-spreading control system according to claim 1, characterized in that: The pump displacement control device comprises a control cylinder (7) and a first solenoid valve (9), wherein the control cylinder (7) is connected to a control end of a variable pump (21), an input end of the first solenoid valve (9) is connected to an output end of the variable pump (21), an output end of the first solenoid valve (9) is connected to a large and small chamber of the control cylinder (7), a first overflow valve (8) is provided between the input end of the first solenoid valve (9) and an oil tank (2), and a throttle valve (6) is provided between an oil outlet end of the first solenoid valve (9) and the oil tank (2).

6. A loader lifting and anti-spreading control system according to claim 5, characterized in that: The first solenoid valve (9) is a three-position four-way proportional solenoid valve with spring return, and the two control ends of the first solenoid valve (9) are connected to the controller (3).

7. A method for using the loader lifting and anti-spreading control system according to claim 1, characterized in that: The two output ends of the main valve (17) are respectively connected to the fifth solenoid valve (16) and the fourth solenoid valve (12); the small cavity of the bucket cylinder (14) is connected to the main valve (17) via the fifth solenoid valve (16); and the large cavity of the bucket cylinder (14) is connected to the main valve (17) via the fourth solenoid valve (12); The pump displacement control device comprises a control cylinder (7) and a first solenoid valve (9), wherein the control cylinder (7) is connected to a control end of a variable displacement pump (21), an input end of the first solenoid valve (9) is connected to an output end of the variable displacement pump (21), an output end of the first solenoid valve (9) is connected to a large and small cavity of the control cylinder (7), a first overflow valve (8) is provided between the input end of the first solenoid valve (9) and the oil tank (2), and a throttle valve (6) is provided between an oil outlet end of the first solenoid valve (9) and the oil tank (2); The steps for boom lifting are as follows: S1. The driver moves the handle (1) toward the boom raising position; S2, the controller (3) inputs an electrical signal to the control ends of the first solenoid valve (9), the second solenoid valve (10), the sixth solenoid valve (18), the fourth solenoid valve (12) and the fifth solenoid valve (16), so that oil flows into the small chamber of the control cylinder (7) and the small chamber of the bucket cylinder (14); S3, as the boom lifting angle increases, the bucket cylinder moves dynamically, and the boom angle sensor (4) and the bucket angle sensor (5) input angle signals to the controller (3). The controller (3) controls the control cylinder (7) and the bucket cylinder (14) according to the preset boom angle and bucket angle relationship, and then adjusts the bucket angle according to the boom angle; S4. When the lifting is completed, the driver releases the handle (1), and the handle (1) returns to the position where the boom is lifted; S5, the controller (3) inputs a 0 electrical signal to the control ends of the second solenoid valve (10), the sixth solenoid valve (18), the fourth solenoid valve (12) and the fifth solenoid valve (16), so that the piston rod of the bucket cylinder (14) is locked at the current position, and the controller (3) inputs a control signal to the first solenoid valve (9) to control the piston rod of the control cylinder (7) to extend, thereby reducing the displacement of the variable pump (21); S6. When the displacement of the variable pump (21) is 0, the controller (3) inputs a 0 electrical signal to the control end of the first solenoid valve (9), the first solenoid valve (9), the valve group control system flow of the boom is 0, the boom lifting valve group is closed, and the boom stops lifting.

8. The method for using the loader lifting and anti-spreading control system according to claim 7, characterized in that: The relationship between the boom angle and the bucket angle is that when the boom is raised from the ground bucket retracted position, the angle of the bucket side blade decreases as the boom angle increases. When the boom angle increases from a negative angle to 0 degrees, the angle of the bucket side blade decreases to 0 degrees. When the boom angle continues to increase from 0 degrees to the highest position, the angle of the bucket side blade remains at 0 degrees.

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