Excavator maximum excavating force control method, hydraulic system and excavator

Abstract

The invention discloses an excavator maximum excavating force control method, a hydraulic system and an excavator. The method comprises the steps that current posture information of the excavator is collected; calculating the maximum digging force of the excavator in the current attitude according to the current attitude information of the excavator; and the maximum working oil pressure of a movable arm oil cylinder, a bucket rod oil cylinder and a bucket oil cylinder is calculated according to the maximum excavating force of the excavator in the current posture and used for controlling the maximum excavating force of the excavator. The maximum excavating force of the excavator can be adjusted according to the posture of the excavator, and the excavator is prevented from overturning during construction on a slope.

Description

Technical Field

[0001] The present invention belongs to the technical field of excavators, and in particular relates to a maximum excavating force control method for an excavator, a hydraulic system and an excavator. Background Art

[0002] During slope operations, as the slope and working posture of the excavator change, the machine's ability to stay on the slope and climb becomes worse, which may lead to dangerous situations such as slipping. When performing slope-staying excavation operations on a slope of 25° to 35°, the posture of the entire vehicle is unstable and the entire vehicle is prone to overturning, causing safety accidents. In the existing technology, when faced with a slope with a large slope, the method of lowering the slope and repairing a zigzag road is generally adopted, which greatly increases the workload and reduces construction efficiency. In addition, the method of lowering the slope and repairing a zigzag road occupies a large area and brings about the hazards of changing the landscape and destroying vegetation. Moreover, the surface soil is deeply disturbed during its construction process, making the surface of the equipment channel loose and uneven in hardness. This brings great difficulties and safety risks to subsequent construction. Summary of the Invention

[0003] To address the deficiencies in the prior art, the present invention provides a method for controlling the maximum digging force of an excavator, a hydraulic system, and an excavator, which can adjust the maximum digging force of the excavator according to the posture of the excavator to prevent the excavator from overturning when constructing on a slope.

[0004] In order to achieve the above object, the technical solution adopted by the present invention is: In a first aspect, a method for controlling the maximum digging force of an excavator includes: collecting current posture information of the excavator; calculating the maximum digging force of the excavator under the current posture based on the current posture information of the excavator; and calculating the maximum working oil pressure of the boom cylinder, the dipper arm cylinder and the bucket cylinder based on the maximum digging force under the current posture of the excavator, for controlling the maximum digging force of the excavator.

[0005] Furthermore, the current posture information of the excavator is collected, including: collecting the inclination angle 1 of the excavator upper vehicle relative to the horizontal plane, the inclination angle 2 of the excavator lower vehicle relative to the horizontal plane, the deflection angle of the excavator upper vehicle relative to the excavator lower vehicle, the stroke of the boom cylinder, the stroke of the dipper cylinder and the stroke of the bucket cylinder.

[0006] In the second aspect, a hydraulic system for controlling the maximum digging force of an excavator is provided, comprising: a boom cylinder, wherein the large chamber of the boom cylinder is connected to the outlet 1 of the boom reversing valve, and the small chamber is connected to the outlet 2 of the boom reversing valve through the inverse proportional relief valve 1; a dipper cylinder, wherein the small chamber of the dipper cylinder is connected to the outlet 2 of the dipper valve, and the large chamber is connected to the outlet 1 of the dipper valve through the inverse proportional relief valve 2; a bucket cylinder, wherein the small chamber of the bucket cylinder is connected to the outlet 1 of the bucket reversing valve, and the large chamber is connected to the outlet 2 of the bucket reversing valve through the inverse proportional relief valve 3. Outlet 2; a controller, wherein the controller is electrically connected to the control ends of the inverse proportional relief valve 1, the inverse proportional relief valve 2 and the inverse proportional relief valve 3, respectively. The controller is configured to obtain the maximum working oil pressure of the boom cylinder, the dipper cylinder and the bucket cylinder through the maximum digging force control method of the excavator described in the first aspect, and set the pressure of the inverse proportional relief valve 1, the inverse proportional relief valve 2 and the inverse proportional relief valve 3 according to the maximum working oil pressure of the boom cylinder, the dipper cylinder and the bucket cylinder, thereby controlling the maximum digging force of the excavator.

[0007] Furthermore, it also includes working pump 1 and working pump 2, the inlet of the boom reversing valve and the inlet of the bucket reversing valve are respectively connected to the outlet of working pump 1; the inlet of the arm reversing valve is connected to the outlet of working pump 2.

[0008] Furthermore, it also includes: an upper vehicle inclination angle sensor for collecting the inclination angle 1 of the excavator upper vehicle relative to the horizontal plane; an lower vehicle inclination angle sensor for collecting the inclination angle 2 of the excavator lower vehicle relative to the horizontal plane; and a rotary encoder for collecting the deflection angle of the excavator upper vehicle relative to the excavator lower vehicle.

[0009] Furthermore, it also includes: a pressure sensor 1 for collecting the pressure of the small cavity of the boom cylinder; a pressure sensor 3 for collecting the pressure of the large cavity of the boom cylinder; and a pressure sensor 5 for collecting the pressure of the large cavity of the bucket cylinder.

[0010] Furthermore, the boom cylinder, the arm cylinder and the bucket cylinder are all provided with stroke sensors.

[0011] Furthermore, the pressures of the inverse proportional relief valve one, inverse proportional relief valve two and inverse proportional relief valve three are set according to the maximum working oil pressures of the boom cylinder, the arm cylinder and the bucket cylinder, including: when the maximum working oil pressure P1 of the small chamber of the boom cylinder ≤ the system pressure P0, the upper limit of the pressure of the inverse proportional relief valve one is adjusted to P1, otherwise it is adjusted to P0; when the maximum working oil pressure P3 of the large chamber of the arm cylinder ≤ the system pressure P0, the upper limit of the pressure of the inverse proportional relief valve two is adjusted to P3, otherwise it is adjusted to P0; when the maximum working oil pressure P5 of the large chamber of the bucket cylinder ≤ the system pressure P0, the upper limit of the pressure of the inverse proportional relief valve three is adjusted to P5, otherwise it is adjusted to P0.

[0012] According to a third aspect, an excavator is provided, wherein the excavator is equipped with the hydraulic system for controlling the maximum excavating force of the excavator according to the second aspect.

[0013] Compared with the prior art, the present invention has the following beneficial effects: the present invention collects the current posture information of the excavator; calculates the maximum digging force of the excavator under the current posture according to the current posture information of the excavator; calculates the maximum working oil pressure of the boom cylinder, the dipper cylinder and the bucket cylinder according to the maximum digging force under the current posture of the excavator, which is used to control the maximum digging force of the excavator, thereby adjusting the maximum digging force of the excavator according to the posture of the excavator and preventing the excavator from overturning when constructing on a slope. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 is a schematic top view of an excavator according to an embodiment of the present invention; Figure 2 is a side view schematic diagram of an excavator in an embodiment of the present invention; Figure 3 This is a schematic diagram of the principle of a hydraulic system for controlling the maximum digging force of an excavator provided by an embodiment of the present invention; Figure 4 The present invention provides a control logic block diagram of a method for controlling the maximum digging force of an excavator. DETAILED DESCRIPTION

[0015] The present invention will be further described below in conjunction with the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solutions of the present invention and are not intended to limit the scope of protection of the present invention.

[0016] Example 1 like Figures 1 to 4 As shown, a method for controlling the maximum digging force of an excavator includes: collecting the current posture information of the excavator; calculating the maximum digging force of the excavator under the current posture according to the current posture information of the excavator; calculating the maximum working oil pressure of the boom cylinder, the dipper cylinder and the bucket cylinder according to the maximum digging force under the current posture of the excavator, so as to control the maximum digging force of the excavator.

[0017] Collect the current posture information of the excavator, including: collecting the inclination angle 1 of the excavator upper vehicle relative to the horizontal plane, the inclination angle 2 of the excavator lower vehicle relative to the horizontal plane, the deflection angle of the excavator upper vehicle relative to the excavator lower vehicle, the stroke of the boom cylinder, the stroke of the dipper cylinder and the stroke of the bucket cylinder.

[0018] Example 2 Based on the method for controlling the maximum digging force of an excavator described in Example 1, this embodiment provides a hydraulic system for controlling the maximum digging force of an excavator. The system includes boom cylinders (including a left boom cylinder G3 and a right boom cylinder G4), an arm cylinder G1, a bucket cylinder G2, and a controller (not shown). The boom cylinders, arm cylinder G1, and bucket cylinder G2 are used to control the movement of the boom, arm, and bucket, respectively, and all are equipped with travel sensors.

[0019] The inlet of the boom reversing valve V5 and the inlet of the bucket reversing valve V6 are respectively connected to the outlet of working pump 1; the inlet of the arm reversing valve V4 is connected to the outlet of working pump 2. The large chamber of the boom cylinder is connected to outlet 1 of boom reversing valve V5, and the small chamber is connected to outlet 2 of boom reversing valve V5 via inverse proportional relief valve 1 V3. The small chamber of the arm cylinder G1 is connected to outlet 2 of arm reversing valve V4, and the large chamber is connected to outlet 1 of arm reversing valve V4 via inverse proportional relief valve 2 V1. The small chamber of the bucket cylinder G2 is connected to outlet 1 of bucket reversing valve V6, and the large chamber is connected to outlet 2 of bucket reversing valve V6 via inverse proportional relief valve 3 V2. Inverse proportional relief valve 1 V3, inverse proportional relief valve 2 V1, and inverse proportional relief valve 3 V2 can control the maximum operating pressure of their respective branches. The controller is electrically connected to the control terminals of inverse proportional relief valve 1 V3, inverse proportional relief valve 2 V1, and inverse proportional relief valve 3 V2, respectively. The controller is configured to obtain the maximum working oil pressure of the boom cylinder, the dipper cylinder G1 and the bucket cylinder G2 through the maximum digging force control method of the excavator described in Example 1, and set the pressure of the inverse proportional relief valve 1 V3, the inverse proportional relief valve 2 V1 and the inverse proportional relief valve 3 V2 according to the maximum working oil pressure of the boom cylinder, the dipper cylinder G1 and the bucket cylinder G2, thereby controlling the maximum digging force of the excavator.

[0020] The outlets of inverse proportional relief valve 1 V3, inverse proportional relief valve 2 V1, and inverse proportional relief valve 3 V2 are all connected to the fuel tank. The oil return ports of the boom cylinder, dipper cylinder G1, and bucket cylinder G2 are all connected to the fuel tank.

[0021] The present invention uses a superstructure inclination sensor, a substructure inclination sensor, a rotary encoder, a boom cylinder stroke sensor, an arm cylinder stroke sensor, and a bucket cylinder stroke sensor to sense the vehicle's posture. The superstructure inclination sensor measures the inclination angle 1 of the excavator superstructure relative to the horizontal plane; the substructure inclination sensor measures the inclination angle 2 of the excavator substructure relative to the horizontal plane; the rotary encoder measures the deflection angle of the excavator superstructure relative to the substructure; the boom cylinder stroke sensor measures the stroke of the boom cylinder; the arm cylinder stroke sensor measures the stroke of the arm cylinder; and the bucket cylinder stroke sensor measures the stroke of the bucket cylinder. (The strokes of the boom, arm, and bucket cylinders provide the angular relationship between the boom, arm, and bucket, which is then used to calculate the required digging force.)

[0022] The present invention also includes a pressure sensor F1 for collecting pressure in the boom cylinder's small chamber (P1), a pressure sensor F2 for collecting pressure in the boom cylinder's large chamber (P2), a pressure sensor F3 for collecting pressure in the arm cylinder's large chamber (P3), a pressure sensor F4 for collecting pressure in the arm cylinder's small chamber (P4), a pressure sensor F5 for collecting pressure in the bucket cylinder's large chamber (P5), and a pressure sensor F6 for collecting pressure in the bucket cylinder's small chamber (P6). In the present invention, the system pressure is P0, and the main valve boost function of conventional excavators is eliminated due to the requirements for steep slope excavation.

[0023] When the excavator is digging on a slope, the boom cylinder piston rod retracts, the arm cylinder piston rod extends, and the bucket cylinder extends. The sensors configured on the vehicle (including travel sensors and pressure sensors on the boom, arm, and bucket cylinders, inclination sensors installed on and off the vehicle, rotary encoders installed in the middle, etc.) can sense the posture of the vehicle and analyze the maximum digging force for safe operation at this time. At this time, the maximum digging force is disassembled and calculated to obtain the maximum pressure provided by the boom, arm, and bucket cylinders respectively (the specific calculation method varies depending on the excavator model and configuration). The upper limit of the pressure oil pressure is then limited by the inverse proportional relief valve installed in the small chamber of the boom, the large chamber of the bucket, and the large chamber of the arm, thereby controlling the maximum digging force of the vehicle and achieving safe operation of standing excavation on a slope with a slope of 25° to 35° to prevent the vehicle from tipping over. The maximum digging force control logic is as follows: Figure 4 As shown, when the maximum working oil pressure P1 of the small chamber of the boom cylinder ≤ the system pressure P0, adjust the pressure upper limit of the inverse proportional relief valve 1 V3 to P1, otherwise it is adjusted to P0; when the maximum working oil pressure P3 of the large chamber of the arm cylinder ≤ the system pressure P0, adjust the pressure upper limit of the inverse proportional relief valve 2 V1 to P3, otherwise it is adjusted to P0; when the maximum working oil pressure P5 of the large chamber of the bucket cylinder ≤ the system pressure P0, adjust the pressure upper limit of the inverse proportional relief valve 3 V2 to P5, otherwise it is adjusted to P0.

[0024] Example 3 Based on the hydraulic system for controlling the maximum digging force of an excavator described in the second embodiment, this embodiment provides an excavator, wherein the excavator is equipped with the hydraulic system for controlling the maximum digging force of an excavator described in the second embodiment.

[0025] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the technical principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for controlling the maximum digging force of an excavator, characterized in that: include: Collect the current posture information of the excavator; Calculating the maximum digging force of the excavator under the current posture according to the current posture information of the excavator; The maximum working oil pressure of the boom cylinder, arm cylinder and bucket cylinder is calculated according to the maximum digging force under the current posture of the excavator, which is used to control the maximum digging force of the excavator.

2. The method for controlling the maximum digging force of an excavator according to claim 1, wherein: Collect the current posture information of the excavator, including: collecting the inclination angle 1 of the excavator upper vehicle relative to the horizontal plane, the inclination angle 2 of the excavator lower vehicle relative to the horizontal plane, the deflection angle of the excavator upper vehicle relative to the excavator lower vehicle, the stroke of the boom cylinder, the stroke of the dipper cylinder and the stroke of the bucket cylinder.

3. A hydraulic system for controlling the maximum digging force of an excavator, characterized in that: include: A boom oil cylinder, wherein the large chamber of the boom oil cylinder is connected to the first outlet of the boom reversing valve, and the small chamber is connected to the second outlet of the boom reversing valve through the first inverse proportional relief valve; A boom cylinder, wherein the small chamber of the boom cylinder is connected to the second outlet of the boom reversing valve, and the large chamber is connected to the first outlet of the boom reversing valve through the second inverse proportional relief valve; A bucket cylinder, wherein the small chamber of the bucket cylinder is connected to the first outlet of the bucket reversing valve, and the large chamber is connected to the second outlet of the bucket reversing valve through the third inverse proportional relief valve; A controller is electrically connected to the control ends of inverse proportional relief valve 1, inverse proportional relief valve 2 and inverse proportional relief valve 3, respectively. The controller is configured to obtain the maximum working oil pressure of the boom cylinder, the dipper cylinder and the bucket cylinder through the maximum digging force control method of the excavator according to any one of claims 1 to 2, and set the pressure of inverse proportional relief valve 1, inverse proportional relief valve 2 and inverse proportional relief valve 3 according to the maximum working oil pressure of the boom cylinder, the dipper cylinder and the bucket cylinder, thereby controlling the maximum digging force of the excavator.

4. The hydraulic system for controlling the maximum digging force of an excavator according to claim 3, characterized in that: It also includes a working pump 1 and a working pump 2. The inlet of the boom reversing valve and the inlet of the bucket reversing valve are respectively connected to the outlet of the working pump 1; the inlet of the arm reversing valve is connected to the outlet of the working pump 2.

5. The hydraulic system for controlling the maximum digging force of an excavator according to claim 3, characterized in that: Also includes: A vehicle inclination sensor for collecting the inclination of the excavator vehicle relative to the horizontal plane; A dismount inclination sensor for collecting the inclination of the excavator dismount relative to the horizontal plane; A rotary encoder used to measure the deflection angle of the excavator upper vehicle relative to the excavator lower vehicle.

6. The hydraulic system for controlling the maximum digging force of an excavator according to claim 3, characterized in that: Also includes: A pressure sensor 1 for collecting the pressure of the small cavity of the boom cylinder; Pressure sensor 3 for collecting the pressure of the large cavity of the boom cylinder; Pressure sensor 5 for collecting the pressure of the bucket cylinder cavity.

7. The hydraulic system for controlling the maximum digging force of an excavator according to claim 3, characterized in that: The boom oil cylinder, the dipper rod oil cylinder and the bucket oil cylinder are all provided with stroke sensors.

8. The hydraulic system for controlling the maximum digging force of an excavator according to claim 3, characterized in that: According to the maximum working oil pressure of the boom cylinder, arm cylinder and bucket cylinder, the pressure of the inverse proportional relief valve 1, inverse proportional relief valve 2 and inverse proportional relief valve 3 is set, including: When the maximum working oil pressure P1 of the small chamber of the boom cylinder is less than or equal to the system pressure P0, adjust the upper limit of the pressure of the inverse proportional relief valve 1 to P1, otherwise adjust it to P0; When the maximum working oil pressure P3 of the large chamber of the boom cylinder is less than or equal to the system pressure P0, adjust the upper limit of the pressure of the inverse proportional relief valve 2 to P3, otherwise adjust it to P0; When the maximum working oil pressure P5 of the bucket cylinder's large chamber is less than or equal to the system pressure P0, adjust the upper pressure limit of the inverse proportional relief valve 3 to P5, otherwise adjust it to P0.

9. An excavator, characterized in that: The excavator is equipped with the excavator maximum digging force control hydraulic system according to any one of claims 3 to 8.

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