Hydraulic travel system, control method of hydraulic travel system, and hydrostatic loader

Abstract

The present application relates to the field of engineering machinery, and discloses a hydraulic walking system, a control method of the hydraulic walking system and a hydrostatic loader, the system comprising: a plunger pump, a front axle motor, a rear axle motor and a shunt collector valve; the plunger pump is used for forward movement or reverse movement based on hydraulic oil; the shunt collector valve is connected with the plunger pump and is used for adjusting the flow direction of the hydraulic oil, so that the hydraulic oil flows into the front axle motor and the rear axle motor in parallel or in series; the front axle motor and the rear axle motor are connected with the shunt collector valve and are used for converting the hydraulic energy of the hydraulic oil into mechanical energy. The present application can realize the forward and reverse rotation of the hydraulic walking and the series and parallel connection of the motor, flexibly adjust the flow direction of the hydraulic oil, thereby providing different walking speeds and tractive forces, so that the small hydrostatic loader can normally operate under different working conditions.

Description

Technical Field

[0001] This invention relates to the field of engineering machinery technology, specifically to a hydraulic walking system, a control method for the hydraulic walking system, and a hydrostatic loader. Background Technology

[0002] Travel speed and traction are core performance characteristics of small hydrostatic loaders, directly affecting overall machine efficiency and the ability to extricate itself from stuck situations. Currently, small hydrostatic loaders typically feature a single-displacement piston pump and dual-cycloidal motor system for their travel hydraulic system, including a piston pump, front axle motor, and rear axle motor. Figure 1 As shown, hydraulic oil exits from port A of the plunger pump, passes through port B1 of the rear axle motor to port A1, then enters port B2 of the front axle motor to port A2. Oil exits from port A2 back to port B of the plunger pump, completing the circulation. The hydraulic oil passes through both the front and rear motors in series. At this point, the machine has only one travel speed and output torque. Therefore, to ensure normal operation, the machine can only operate with the front and rear motors connected in series to maintain a high speed. However, this restricts motor usage, resulting in lower output torque and consequently lower traction. When the machine gets stuck, the low traction makes it difficult to escape. Summary of the Invention

[0003] In view of this, the present invention provides a hydraulic walking system, a control method for the hydraulic walking system, and a hydrostatic loader to solve the problem of limitations in hydraulic walking systems.

[0004] In a first aspect, the present invention provides a hydraulic walking system, comprising: a piston pump, a front axle motor, a rear axle motor, and a flow divider / combiner valve; the piston pump is used for forward or reverse motion based on hydraulic oil; the flow divider / combiner valve is connected to the piston pump and is used to adjust the flow direction of the hydraulic oil so that the hydraulic oil flows into the front axle motor and the rear axle motor in parallel or series; the front axle motor and the rear axle motor are connected to the flow divider / combiner valve and are used to convert the hydraulic energy of the hydraulic oil into mechanical energy.

[0005] The hydraulic walking system provided by this invention, by setting a flow divider and combiner valve between the piston pump and the front and rear axle motors, adjusts the flow direction of the hydraulic oil flowing out of the piston pump in the forward or reverse motion, so that the hydraulic oil flows into the front and rear axle motors in parallel or series form. This enables forward and reverse hydraulic walking and series and parallel connection of the motors, and flexibly adjusts the flow direction of the hydraulic oil, thereby providing different walking speeds and traction forces, so that the small hydrostatic loader can operate normally under different working conditions.

[0006] In one optional embodiment, the flow divider / combiner valve includes: a shuttle valve, a balance valve, a two-position three-way solenoid valve, and a directional control valve; the shuttle valve has two ends connected to the two ends of a piston pump, respectively, for controlling the forward or reverse movement direction of the hydraulic oil; the balance valve has a first port connected to the first port of the piston pump, and a second and third port connected to the first and second ports of the directional control valve, respectively, for evenly distributing the hydraulic oil input from the first port into a first path and a second path, or combining the first and second paths input from the second and third ports into one path; the two-position three-way solenoid valve has a first end connected to the third port of the shuttle valve, and a second port connected to the valve control port of the directional control valve, for adjusting the conduction direction of the directional control valve; the directional control valve has a first port and a second port connected to the two ends of a front axle motor or a rear axle motor, respectively, for controlling the flow direction of the first and second paths of oil based on the conduction direction, allowing the first and second paths of oil to flow into the front axle motor and the rear axle motor in parallel or series.

[0007] This invention, by deploying shuttle valves, balance valves, two-position three-way solenoid valves, and directional control valves according to a specific connection method, can control the flow direction of hydraulic oil, evenly distribute it into two paths, realize the parallel and series connection of the front and rear motors, and thus realize the high and low speed control and reverse rotation control of the front and rear motors.

[0008] In one optional embodiment, the directional control valve includes: a first directional valve, a second directional valve, a third directional valve, and a fourth directional valve connected in sequence, wherein the first port of the first directional valve is connected to the second port of the balance valve and the first port of the front axle motor, and the second port is connected to the third port of the balance valve and the first port of the second directional valve; the second port of the second directional valve is connected to the second port of the rear axle motor and the first port of the third directional valve; the second port of the third directional valve is connected to the second port of the front axle motor and the first port of the fourth directional valve; the second port of the fourth directional valve is connected to the second port of the plunger pump and the first port of the rear axle motor; and the valve control ports of the first directional valve, the second directional valve, the third directional valve, and the second directional valve are all connected to the second port of the two-position three-way solenoid valve.

[0009] This invention, by deploying multiple steering valves, can input two hydraulic oil lines into the front and rear axle motors in series or parallel, providing different travel speeds and traction forces for small hydrostatic loaders, enabling them to operate normally under different working conditions.

[0010] In one optional implementation, the directional control valve is any one of a switching electromagnetic directional control valve, a proportional electromagnetic directional control valve, a hydraulic directional control valve, or a manual directional control valve.

[0011] This invention, by deploying a steering valve, enables the hydraulic oil to be opened or closed by controlling the valves inside the steering valve, thereby providing different flow directions and allowing the hydraulic oil to flow into the front and rear axle motors in parallel or series.

[0012] Secondly, the present invention provides a control method for a hydraulic travel system, the hydraulic travel system including a piston pump, a flow divider / combiner valve, a front axle motor, and a rear axle motor, wherein the piston pump is connected to the front axle motor and the rear axle motor through the flow divider / combiner valve, and the control method for the hydraulic travel system includes:

[0013] The piston pump is controlled to pressurize hydraulic oil into the flow divider and combiner valve according to the working status, either in a forward or reverse motion.

[0014] Control the valve direction of the flow divider and combiner valve to allow hydraulic oil to flow into the front axle motor and the rear axle motor in parallel or series configuration;

[0015] The hydraulic oil flowing from the front axle motor and the rear axle motor is drawn into the piston pump in either forward or reverse motion.

[0016] The control method of the hydraulic walking system provided by this invention controls the forward or reverse movement of the piston pump according to different working states. The flow direction of the hydraulic oil is adjusted by the flow divider and collector valve, so that the hydraulic oil flows into the front axle motor and the rear axle motor in parallel or series form, and is sucked into the piston pump after flowing out. This can realize the forward and reverse rotation of hydraulic walking and the series and parallel connection of motors. The flow direction of the hydraulic oil can be flexibly adjusted, thereby providing different walking speeds and traction forces, so that the small hydrostatic loader can operate normally under different working conditions.

[0017] In one optional embodiment, the flow divider / combiner valve includes: a shuttle valve, a balance valve, a two-position three-way solenoid valve, and a directional control valve. The directional control valve includes: a first directional control valve, a second directional control valve, a third directional control valve, and a fourth directional control valve. The shuttle valve's two ends are respectively connected to the two ends of a piston pump. The first port of the balance valve is connected to the first port of the piston pump, and its second and third ports are respectively connected to the first and second ports of the first directional control valve. The first end of the two-position three-way solenoid valve is connected to the third port of the shuttle valve, and its second port is connected to the valve control port of each directional control valve. The first port of the first directional control valve is connected to the first port of the front axle motor, and its second port is connected to the first port of the second directional control valve. The second port of the second directional control valve is connected to the second port of the rear axle motor and the first port of the third directional control valve. The second port of the third directional control valve is connected to the second port of the front axle motor and the first port of the fourth directional control valve. The second port of the fourth directional control valve is connected to the second end of the piston pump. The first port of the front axle motor is connected to the second port of the flow divider / combiner valve. The valve direction of the flow divider / combiner valve is controlled to allow hydraulic oil to flow into the front axle motor and rear axle motor in parallel. This includes: if the piston pump moves in the forward direction, the first port of the shuttle valve in the flow divider / combiner valve is opened, and the first port of the two-position three-way solenoid valve in the flow divider / combiner valve is controlled to be in the spring position. This disconnects both ends of the first directional valve in the flow divider / combiner valve, opens both ends of the second directional valve, disconnects both ends of the third directional valve, and opens both ends of the fourth directional valve. The hydraulic oil passes through the first port of the balance valve in the flow divider / combiner valve and is divided into a first oil path and a second oil path through the second and third ports. The first oil path flows into the first port of the front axle motor, flows out from the second port of the front axle motor to the first port of the fourth directional valve, and flows out from the second port of the fourth directional valve. The second oil path flows into the first port of the second directional valve, flows out from the second port of the second directional valve to the second port of the rear axle motor, and flows out from the first port of the rear axle motor.

[0018] This invention controls the hydraulic oil to flow out in a forward motion and simultaneously flow into the front and rear axle motors in parallel, which ensures that the motors rotate or move at low speeds while outputting high torque, thus enabling the entire machine to move forward with high traction.

[0019] In one optional implementation, controlling the valve direction of the flow divider / combiner valve to allow hydraulic oil to flow into the front axle motor and the rear axle motor in parallel further includes: if the piston pump moves in the reverse direction, then the second port of the shuttle valve in the flow divider / combiner valve is opened, and the first port of the two-position three-way solenoid valve in the flow divider / combiner valve is controlled to be in the spring position, thus disconnecting both ends of the first directional valve, opening both ends of the second directional valve, disconnecting both ends of the third directional valve, and opening both ends of the fourth directional valve in the flow divider / combiner valve; the hydraulic oil is divided into a first path and a second path, the first path flows into the second port of the fourth directional valve, flows out from the first port of the fourth directional valve to the second port of the front axle motor, and flows out from the first port of the front axle motor; the second path flows into the first port of the rear axle motor, flows out from the second port of the rear axle motor to the second port of the second directional valve, and flows out from the first port of the second directional valve; the second path flowing out from the first port of the second directional valve flows into the second port of the balance valve, flows out from the first port of the front axle motor, flows into the third port of the balance valve, and flows out through the first port of the balance valve to merge into one hydraulic oil path.

[0020] This invention controls the hydraulic oil to flow out in the opposite direction and simultaneously flow into the front and rear axle motors in parallel, which can ensure that the motors rotate or move at low speed in the opposite direction. At this time, the motor outputs a large torque, and the whole machine moves backward with a large traction force.

[0021] In one optional implementation, controlling the valve direction of the flow divider / combiner valve to allow hydraulic oil to flow into the front axle motor and the rear axle motor in series includes: if the piston pump is moving in the forward direction, then the first port of the shuttle valve in the flow divider / combiner valve is opened, and the first port of the two-position three-way solenoid valve in the flow divider / combiner valve is controlled to be in the solenoid valve position, opening both ends of the first directional valve, disconnecting both ends of the second directional valve, opening both ends of the third directional valve, and disconnecting both ends of the fourth directional valve in the flow divider / combiner valve; the hydraulic oil passes through the first port of the balance valve in the flow divider / combiner valve, and is divided into a first oil path and a second oil path through the second and third ports; the second oil path flows into the second port of the first directional valve, flows out from the first port of the second directional valve and flows together with the first oil path into the first port of the front axle motor, flows out from the second port of the front axle motor to the second port of the third directional valve, flows out from the first port of the third directional valve to the second port of the rear axle motor, and flows out from the first port of the rear axle motor.

[0022] This invention controls the hydraulic oil to flow out in a forward motion and flow into the front and rear axle motors in series, which can ensure that the motors rotate or move at high speed, and at this time the whole machine moves forward at high speed.

[0023] In one optional implementation, controlling the valve direction of the flow divider / combiner valve to allow hydraulic oil to flow into the front axle motor and the rear axle motor in series includes: if the piston pump moves in the reverse direction, then the second port of the shuttle valve in the flow divider / combiner valve is opened, and the first port of the two-position three-way solenoid valve in the flow divider / combiner valve is controlled to be in the solenoid valve position, opening both ends of the first directional valve, disconnecting both ends of the second directional valve, opening both ends of the third directional valve, and disconnecting both ends of the fourth directional valve in the flow divider / combiner valve; the hydraulic oil flows into the first port of the rear axle motor, flows out from the second port of the rear axle motor to the first port of the third directional valve, flows out from the second port of the third directional valve to the second port of the front axle motor, flows out from the first port of the front axle motor to the second port of the balance valve, or flows into the third port of the balance valve after passing through the first directional valve, and flows out from the first port of the balance valve.

[0024] This invention controls the hydraulic oil to flow out in a reverse motion and flow into the front and rear axle motors in series, which can ensure that the motors rotate or move at high speed in the opposite direction, and at this time the whole machine reverses at high speed.

[0025] Thirdly, the present invention provides a hydrostatic loader, including the hydraulic walking system of the first aspect above or any corresponding embodiment thereof. Attached Figure Description

[0026] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0027] Figure 1 This is a structural block diagram of the walking hydraulic system of a single fixed displacement piston pump and dual cycloidal motor system according to an embodiment of the present invention;

[0028] Figure 2 This is a structural block diagram of a hydraulic walking system according to an embodiment of the present invention;

[0029] Figure 3 This is a flowchart illustrating the control method of a hydraulic walking system according to an embodiment of the present invention;

[0030] Figure 4 This is a schematic diagram of the parallel connection of the control method of the hydraulic walking system according to an embodiment of the present invention.

[0031] Figure 5 This is a flowchart illustrating a control method for another hydraulic walking system according to an embodiment of the present invention;

[0032] Figure 6This is a schematic diagram of the series connection of a control method for another hydraulic walking system according to an embodiment of the present invention.

[0033] Figure diagram labels: 100-Plunger pump; 200-Flow divider / combiner valve; 201-Shuttle valve; 202-Balance valve; 203-Two-position three-way solenoid valve; 204-First directional valve; 205-Second directional valve; 206-Third directional valve; 207-Fourth directional valve; 301-Front axle motor; 302-Rear axle motor. Detailed Implementation

[0034] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0035] This invention is applicable to scenarios where the hydraulic travel system of a small hydrostatic loader is controlled according to working conditions. For example... Figure 1 As shown, in the current single-displacement piston pump and dual-cycloidal motor system of small hydrostatic presses, hydraulic oil exits from port A of the pump, passes through port B1 of the rear motor to port A1, then enters port B2 of the front motor to port A2, and exits from port A2 back to port B of the pump to complete the cycle. The hydraulic oil passes through both the front and rear motors in series. In this configuration, the entire machine has only one travel speed and traction force, which limits its use. Therefore, this invention provides a hydraulic travel system that, by deploying a flow divider and combiner valve, allows for flexible adjustment of the flow direction of the hydraulic oil within the system.

[0036] According to an embodiment of the present invention, a hydraulic walking system embodiment is provided. Figure 2 This is a structural block diagram of a hydraulic walking system according to an embodiment of the present invention, such as... Figure 2 As shown, the system includes: a piston pump 100, a flow divider / combiner valve 200, a front axle motor 301, and a rear axle motor 302; the piston pump 100 is used for forward or reverse motion based on hydraulic oil; the flow divider / combiner valve 200, connected to the piston pump 100, is used to adjust the flow direction of the hydraulic oil, so that the hydraulic oil flows into the front axle motor 301 and the rear axle motor 302 in parallel or series; the front axle motor 301 and the rear axle motor 302, connected to the flow divider / combiner valve 200, are used to convert the hydraulic energy of the hydraulic oil into mechanical energy.

[0037] Specifically, in embodiments of the present invention, such as Figure 2As shown, the flow divider / combiner valve 200 includes: a shuttle valve 201, a balance valve 202, a two-position three-way solenoid valve 203, and a directional control valve. The directional control valve includes: a first directional valve 204, a second directional valve 205, a third directional valve 206, and a fourth directional valve 207 connected in sequence. These directional control valves are interconnected to form four ports: A1, A2, B1, and B2. M1 and M2 are ports for the front axle motor 301, serving as inlet and outlet ports for each other; M3 and M4 are ports for the rear axle motor 302, also serving as inlet and outlet ports for each other. Ports A and B are ports for the plunger pump, serving as inlet and outlet ports for each other. If the flow enters from port A and returns from port B, it is a forward motion; if the flow enters from port B and returns from port A, it is a reverse motion.

[0038] In some alternative implementations, such as Figure 2 As shown, in the flow divider / combiner valve 200 of this embodiment, the two ends of the shuttle valve 201 are respectively connected to the two ends of the plunger pump 100: port A and port B, for controlling the forward or reverse movement direction of the hydraulic oil. The first port of the balance valve 202 is connected to the first port A of the plunger pump 100, and the second and third ports are respectively connected to the first port a1 and the second port a2 of the first directional valve 204, for distributing the hydraulic oil input from the first port evenly into the first oil path and the second oil path, or combining the first oil path and the second oil path input from the second and third ports into one path. The first end of the two-position three-way solenoid valve 203 is connected to the third port of the shuttle valve 201, and the second port is connected to the valve control ports of the first directional valve 204, the second directional valve 205, the third directional valve 206, and the fourth directional valve 207, for adjusting the conduction direction of the first directional valve 204, the second directional valve 205, the third directional valve 206, and the fourth directional valve 207. The directional control valve is used to control the flow direction of the first and second oil channels based on the conduction direction, allowing the first and second oil channels to flow into the front axle motor and the rear axle motor in parallel or series.

[0039] In some alternative implementations, such as Figure 2 As shown, the first port a1 of the first directional valve 204 is connected to the first port M1 of the front axle motor 301, the second port a2 is connected to the first port a3 of the second directional valve 205, the second port a4 of the second directional valve is connected to the second port M4 of the rear axle motor 302 and the first port a5 of the third directional valve 206, the second port a6 of the third directional valve 206 is connected to the second port M2 of the front axle motor 301 and the first port a7 of the fourth directional valve 207, and the second port a8 of the fourth directional valve 207 is connected to the second port B of the piston pump 100 and the first port M3 of the rear axle motor 302. Therefore, the normally open ports of the hydraulic travel system include: a1 connected to A1, a4, a5 connected to A2, a6, a7 connected to B1, and a8 connected to B2.

[0040] In some optional embodiments, the flow divider / combiner valve 200 switches different oil circuits by actuating a solenoid valve, allowing high-pressure hydraulic oil entering through port A or port B to flow out from different outlets as needed, thereby controlling the series and parallel connection of the front and rear axle motors and achieving torque switching. Specifically, in parallel connection, the front axle motor 301 and the rear axle motor 302 equally distribute the oil flow through ports A1 and A2 or B1 and B2, with the hydraulic oil entering the front and rear motors simultaneously without any order. In series connection, the hydraulic oil entering through port A1 or B2 passes through the front axle motor 301 and the rear axle motor 302 sequentially, the order determined by the specific inlet port.

[0041] In some optional embodiments, the shuttle valve 201 operates primarily by controlling the flow of the medium through the up-and-down movement of the valve core on the valve seat, thereby achieving fluid regulation and control. Specifically, when the actuator applies force to move the valve core up and down, the gap between the valve core and the valve seat changes, thus affecting the flow of the medium. When the valve core rises, the gap widens, allowing the medium to pass smoothly; when the valve core descends, the gap narrows, restricting the flow of the medium. In this embodiment of the invention, the shuttle valve 201 achieves forward and reverse rotation of the hydraulic travel system by connecting to port A or port B through the up-and-down movement of the valve core.

[0042] In some alternative implementations, the balancing valve 202 operates by changing the gap (opening) between the valve core and the valve seat, thereby altering the flow resistance through the valve and thus regulating the flow rate. This regulation targets the system's resistance, enabling the hydraulic oil to be distributed in a balanced manner according to the designed proportions, ensuring that each branch still meets the flow requirements under partial load, thus achieving a balancing effect. In this embodiment of the invention, the balancing valve 202 divides the hydraulic oil into two equally spaced paths.

[0043] In some optional implementations, the working principle of the two-position three-way solenoid valve 203 mainly includes two aspects: electromagnetic principle and mechanical principle. The electromagnetic principle controls the valve's opening and closing by the attraction and release of an electromagnet. When the electromagnet is energized, it generates a magnetic field, attracting the iron core and thus opening the valve; when the electromagnet is de-energized, the iron core loses its magnetism, and the valve closes. The mechanical principle controls the flow direction of the medium by the movement of the valve core. When the electromagnet is energized, the valve core is attracted, changing the flow direction of the medium; when the electromagnet is de-energized, the valve core returns to its original position under the action of a spring, and the flow direction of the medium is restored. This is merely an example and not a limitation. Figure 2 As shown, in this embodiment of the invention, the two-position three-way solenoid valve 203 has its valve position on the lower side and the solenoid valve position on the upper side, thereby realizing the conduction between the shuttle valve 201 and each steering valve. This allows control oil flowing from the shuttle valve 201 through the two-position three-way solenoid valve 203 into the steering valve to adjust the conduction state of the steering valve. The flow direction of the control oil is as follows: Figure 2 As shown by the dashed line.

[0044] In some alternative implementations, the directional control valve operates by changing the flow direction of hydraulic oil through the relative movement of the valve core within the valve body, thereby changing the direction of motion of the actuator. The directional control valve has two or more flow patterns and two or more ports, primarily achieving the communication, disconnection, and reversal of hydraulic oil flow, as well as pressure unloading and sequential action control, through the relative movement of the valve core and valve body. The directional control valve can be configured as a multi-operation type, such as a switch-type solenoid directional control valve, a proportional solenoid directional control valve, a hydraulically controlled directional control valve, and a manual directional control valve; these are merely examples and not limitations. Figure 2 As shown, the directional control valve in this embodiment of the invention includes a check valve and a steering valve. The one-way valve or the two-way valve is opened by control oil, and the specific opening condition is determined according to the working state of the hydraulic walking system.

[0045] The hydraulic walking system provided by this invention, by setting a flow divider and combiner valve between the piston pump and the front and rear axle motors, adjusts the flow direction of the hydraulic oil flowing out of the piston pump in the forward or reverse motion, so that the hydraulic oil flows into the front and rear axle motors in parallel or series. This enables forward and reverse hydraulic walking and series and parallel connection of the motors, and flexibly adjusts the flow direction of the hydraulic oil, thereby providing different walking speeds and traction forces. This allows the small hydrostatic loader to operate normally under different working conditions. Moreover, the various solenoid valves are integrated into the flow divider and combiner valve, making the system small in size, highly integrated, and easy to operate. The control methods include electric control, hydraulic control, and manual control.

[0046] According to an embodiment of the present invention, a control method embodiment for a hydraulic walking system is provided. It should be noted that the steps shown in the flowchart in the accompanying drawings can be executed in a computer system such as a set of computer-executable instructions. Furthermore, although a logical order is shown in the flowchart, in some cases, the steps shown or described may be executed in a different order than that shown here.

[0047] This embodiment provides a control method for a hydraulic walking system, which can be used in the above-mentioned... Figure 2 The hydraulic walking system shown, Figure 3 This is a flowchart of a control method for a hydraulic walking system according to an embodiment of the present invention, such as... Figure 3 As shown, the process includes the following steps:

[0048] Step S301: Control the plunger pump to pressurize hydraulic oil into the flow divider valve in a forward or reverse motion according to the working state.

[0049] Step S302: Control the valve direction of the flow divider and combiner valve to allow hydraulic oil to flow into the front axle motor and the rear axle motor in parallel.

[0050] Step S303: The hydraulic oil flowing out of the front axle motor and the rear axle motor is drawn into the piston pump in a forward or reverse motion manner.

[0051] Specifically, in this embodiment of the invention, when the hydrostatic loader is in working or getting out of trouble, if A is in working state, the plunger pump moves in the forward direction, that is, the hydraulic oil flows out from port A. After the hydraulic oil flows into the shuttle valve, it moves the valve core of the shuttle valve downward, so that the first port and the third port of the shuttle valve are connected. The control oil flowing through the shuttle valve flows to the first port of the two-position three-way solenoid valve. At this time, by controlling the power off via the switch, the first port of the two-position three-way solenoid valve is in the spring position, causing the two ends of the first directional valve to be disconnected, the two ends of the second directional valve to be connected, the two ends of the third directional valve to be disconnected, and the two ends of the fourth directional valve to be connected. At this time, port A1 of the first directional valve is connected to port A1, port A1 is not connected to port A2, port A3 of the second directional valve is connected to port A4, port A4 of the second directional valve and port A5 of the third directional valve are connected to port A2, port A5 of the third directional valve is not connected to port A6, port B1 is connected to ports A7 and A8 of the fourth directional valve, and port B2 is connected to port A8 of the fourth directional valve. The connection status of the hydraulic travel system is as follows. Figure 4 As shown. The hydraulic oil flowing out of port A passes through the first port of the balance valve in the flow divider valve, and is then divided into a first path and a second path through the second and third ports. The first path flows into the first port M1 of the front axle motor, flows out from the second port M2 of the front axle motor to the first port a7 of the fourth steering valve, and flows out from the second port a8 of the fourth steering valve. The second path flows into the first port a3 of the second steering valve, flows out from the second port a4 of the second steering valve to the second port M4 of the rear axle motor, and flows out from the first port M3 of the rear axle motor. The hydraulic oil flowing out of a8 and M3 simultaneously flows into port B of the piston pump. At this time, the front and rear axle motors are connected in parallel, and the motors rotate or move at low speed. At this time, the motors output high torque, and the whole machine moves forward with high traction.

[0052] In some alternative implementations, when the hydrostatic loader is in operation or in a tackling condition, if port B is in operation, the piston pump moves in the reverse direction, that is, the hydraulic oil flows out from port B and flows into the shuttle valve, which moves the valve core of the shuttle valve upward, thereby connecting the second port and the third port of the shuttle valve. The control oil flowing through the shuttle valve flows to the first port of the two-position three-way solenoid valve. At this time, by switching off the power, the first port of the two-position three-way solenoid valve is in the spring position, causing the two ends of the first directional valve to be disconnected, the two ends of the second directional valve to be connected, the two ends of the third directional valve to be disconnected, and the two ends of the fourth directional valve to be connected. At this time, port A1 of the first directional valve is connected to port A1, port A1 is not connected to port A2, port A3 of the second directional valve is connected to port A4, port A4 of the second directional valve and port A5 of the third directional valve are connected to port A2, port A5 of the third directional valve is not connected to port A6, port B1 is connected to ports A7 and A8 of the fourth directional valve, and port B2 is connected to port A8 of the fourth directional valve. The connection status of the hydraulic walking system is as follows. Figure 4 As shown. The hydraulic oil flowing out from port B is divided into a first path and a second path. The first path flows into the second port a8 of the fourth steering valve, flows out from the first port a7 of the fourth steering valve to the second port M2 of the front axle motor, and then flows out from the first port M1 of the front axle motor. The second path flows into the first port M3 of the rear axle motor, flows out from the second port M4 of the rear axle motor to the second port a4 of the second steering valve, and then flows out from the first port a3 of the second steering valve. The second path flowing out from the first port a3 of the second steering valve flows into the second port of the balance valve, flows out from the first port M1 of the front axle motor, flows into the third port of the balance valve, and then flows out from the first port of the balance valve, merging into one hydraulic oil path, which flows into port A of the plunger pump. At this time, the front and rear axle motors are connected in parallel, and the motors rotate or move in opposite directions at low speed. At this time, the motors output high torque, and the whole machine has a large traction force for backward movement.

[0053] The control method of the hydraulic walking system provided by this invention controls the forward or reverse movement of the piston pump according to different working states. The flow direction of the hydraulic oil is adjusted by the flow divider and collector valve, so that the hydraulic oil flows into the front axle motor and the rear axle motor in parallel or series form, and is sucked into the piston pump after flowing out. This can realize the forward and reverse rotation of hydraulic walking and the series and parallel connection of motors. The flow direction of the hydraulic oil can be flexibly adjusted, thereby providing different walking speeds and traction forces, so that the small hydrostatic loader can operate normally under different working conditions.

[0054] This embodiment provides a control method for a hydraulic walking system, which can be used in the above-mentioned... Figure 2 The hydraulic walking system shown, Figure 5 This is a flowchart of a control method for a hydraulic walking system according to an embodiment of the present invention, such as... Figure 5 As shown, the process includes the following steps:

[0055] Step S501: Control the plunger pump to pressurize hydraulic oil into the flow divider valve in a forward or reverse motion according to the working state.

[0056] Step S502: Control the valve direction of the flow divider and combiner valve to allow hydraulic oil to flow into the front axle motor and the rear axle motor in series.

[0057] Step S503: The hydraulic oil flowing out of the front axle motor and the rear axle motor is drawn into the piston pump in a forward or reverse motion manner.

[0058] Specifically, in this embodiment of the invention, when the hydrostatic loader is in the field transfer condition, if A is in the working state, the plunger pump moves in the forward direction, that is, the hydraulic oil flows out from port A. After the hydraulic oil flows into the shuttle valve, it moves the valve core of the shuttle valve downward, so that the first port and the third port of the shuttle valve are connected. The control oil flowing through the shuttle valve flows to the first port of the two-position three-way solenoid valve. At this time, the first port of the two-position three-way solenoid valve is in the solenoid valve position by controlling the switch, so that both ends of the first directional valve are connected, both ends of the second directional valve are disconnected, both ends of the third directional valve are connected, and both ends of the fourth directional valve are disconnected. At this time, the a1 port of the first directional valve is connected to the A1 oil port, the a1 port of the first directional valve is connected to the a2 port of the first directional valve, the a3 port of the second directional valve is not connected to the a4 port of the second directional valve, the A2 oil port is connected to the a5 and a6 ports of the third directional valve, the B1 oil port is connected to the a6 port of the third directional valve, the a7 port of the fourth directional valve is not connected to the a8 port of the fourth directional valve, and the B2 oil port is connected to the a8 port of the fourth directional valve. The connection status of the hydraulic walking system is as follows. Figure 6 As shown. The hydraulic oil flowing out from port A passes through the first port of the balance valve in the flow divider valve, and is then divided into a first path and a second path through the second and third ports. The second path flows into the second port a2 of the first steering valve, flows out from the first port a1 of the first steering valve, and then flows together with the first path into the first port M1 of the front axle motor. From the second port M2 of the front axle motor, it flows out to the second port a6 of the third steering valve, and from the first port a5 of the third steering valve, it flows to the second port M4 of the rear axle motor. From the first port M3 of the rear axle motor, it flows into port B of the piston pump. At this time, the front and rear motors are connected in series, and the motors rotate or move at high speed, causing the entire vehicle to move forward at a high speed.

[0059] In some alternative implementations, when the hydrostatic loader is in a transfer working condition, if B is in working state, the plunger pump moves in the reverse direction, that is, the hydraulic oil flows out from port B and flows into the shuttle valve, which moves the valve core of the shuttle valve upward, thereby connecting the second port and the third port of the shuttle valve. The control oil flowing through the shuttle valve flows to the first port of the two-position three-way solenoid valve. At this time, the first port of the two-position three-way solenoid valve is in the solenoid valve position by controlling the switch, so that both ends of the first directional valve are connected, both ends of the second directional valve are disconnected, both ends of the third directional valve are connected, and both ends of the fourth directional valve are disconnected. At this time, the a1 port of the first directional valve is connected to the A1 oil port, the a1 port of the first directional valve is connected to the a2 port of the first directional valve, the a3 port of the second directional valve is not connected to the a4 port of the second directional valve, the A2 oil port is connected to the a5 and a6 ports of the third directional valve, the B1 oil port is connected to the a6 port of the third directional valve, the a7 port of the fourth directional valve is not connected to the a8 port of the fourth directional valve, and the B2 oil port is connected to the a8 port of the fourth directional valve. The connection status of the hydraulic walking system is as follows. Figure 6 As shown. Hydraulic oil flowing from port B flows into the first port M3 of the rear axle motor, then flows out from the second port M4 of the rear axle motor to the first port a5 of the third steering valve, then from the second port a6 of the third steering valve to the second port M2 of the front axle motor, then from the first port M1 of the front axle motor to the second port of the balance valve, or flows through the first steering valve into the third port of the balance valve, and then from the first port of the balance valve to port A of the plunger pump. At this time, the front and rear motors are in series, and the motors rotate or move in opposite directions at high speed, causing the entire vehicle to reverse at high speed.

[0060] The control method of the hydraulic walking system provided by this invention controls the forward or reverse movement of the piston pump according to different working states. The flow direction of the hydraulic oil is adjusted by the flow divider and collector valve, so that the hydraulic oil flows into the front axle motor and the rear axle motor in parallel or series form, and is sucked into the piston pump after flowing out. This can realize the forward and reverse rotation of hydraulic walking and the series and parallel connection of motors. The flow direction of the hydraulic oil can be flexibly adjusted, thereby providing different walking speeds and traction forces, so that the small hydrostatic loader can operate normally under different working conditions.

[0061] The present invention also provides a hydrostatic loader, including as follows: Figure 2 The hydraulic walking system shown.

[0062] Although embodiments of the invention have been described in conjunction with the accompanying drawings, those skilled in the art can make various modifications and variations without departing from the spirit and scope of the invention, and such modifications and variations all fall within the scope defined by the appended claims.

Claims

1. A hydraulic travel system, comprising a piston pump, a front axle motor, and a rear axle motor, characterized in that, The system also includes: a flow divider / combiner valve; The plunger pump is used to perform forward or reverse motion based on hydraulic oil; The flow divider and combiner valve is connected to the plunger pump and is used to adjust the flow direction of the hydraulic oil so that the hydraulic oil flows into the front axle motor and the rear axle motor in parallel or series. The front axle motor and the rear axle motor are connected to the flow divider and combiner valve to convert the hydraulic energy of the hydraulic oil into mechanical energy. The flow divider and combiner valve includes: a shuttle valve, a balance valve, a two-position three-way solenoid valve, and a directional control valve; The shuttle valve is connected to both ends of the plunger pump and is used to control the forward or reverse movement of the hydraulic oil. The balance valve has a first port connected to the first port of the piston pump, and a second port and a third port connected to the first port and the second port of the directional control valve, respectively. It is used to evenly distribute the hydraulic oil input from the first port into a first oil path and a second oil path, or to combine the first oil path and the second oil path input from the second port and the third port into one path. The two-position three-way solenoid valve has its first end connected to the third port of the shuttle valve and its second port connected to the valve control port of the directional control valve, for adjusting the conduction direction of the directional control valve. The directional control valve has a first port and a second port connected to the two ends of the front axle motor or the rear axle motor, respectively, and is used to control the flow direction of the first oil and the second oil based on the conduction direction, so that the first oil and the second oil flow into the front axle motor and the rear axle motor in the parallel or series configuration. The directional control valve includes: a first directional valve, a second directional valve, a third directional valve, and a fourth directional valve connected in sequence, wherein, The first port of the first reversing valve is connected to the second port of the balance valve and the first port of the front axle motor, and the second port is connected to the third port of the balance valve and the first port of the second reversing valve. The second port of the second reversing valve is connected to the second port of the rear axle motor and the first port of the third reversing valve; The second port of the third reversing valve is connected to the second port of the front axle motor and the first port of the fourth reversing valve; The second port of the fourth reversing valve is connected to the second port of the plunger pump and the first port of the rear axle motor. The valve control ports of the first reversing valve, the second reversing valve, the third reversing valve, and the second reversing valve are all connected to the second port of the two-position three-way solenoid valve.

2. The system according to claim 1, characterized in that, The directional control valve is any one of a switching electromagnetic directional control valve, a proportional electromagnetic directional control valve, a hydraulic directional control valve, or a manual directional control valve.

3. A control method for a hydraulic walking system, characterized in that, The hydraulic travel system includes a piston pump, a flow divider / combiner valve, a front axle motor, and a rear axle motor, wherein the piston pump is connected to the front axle motor and the rear axle motor through the flow divider / combiner valve, and the control method of the hydraulic travel system includes: The plunger pump is controlled to pressurize hydraulic oil into the flow divider and combiner valve in a forward or reverse motion according to the working status; Control the valve direction of the flow divider and combiner valve to allow the hydraulic oil to flow into the front axle motor and the rear axle motor in parallel or series configuration; The hydraulic oil flowing out of the front axle motor and the rear axle motor is drawn into the plunger pump in the manner of the forward motion or the reverse operation; The flow divider / combiner valve includes: a shuttle valve, a balance valve, a two-position three-way solenoid valve, and a directional control valve. The directional control valve includes: a first directional control valve, a second directional control valve, a third directional control valve, and a fourth directional control valve. The shuttle valve is connected to both ends of the plunger pump; the first port of the balance valve is connected to the first port of the plunger pump, and the second and third ports are connected to the first and second ports of the first directional valve, respectively; the first end of the two-position three-way solenoid valve is connected to the third port of the shuttle valve, and the second port is connected to the valve control port of each of the directional control valves. The first port of the first reversing valve is connected to the first port of the front axle motor, and the second port is connected to the first port of the second reversing valve; the second port of the second reversing valve is connected to the second port of the rear axle motor and the first port of the third reversing valve; the second port of the third reversing valve is connected to the second port of the front axle motor and the first port of the fourth reversing valve; the second port of the fourth reversing valve is connected to the second port of the plunger pump and the first port of the rear axle motor. The control of the valve direction of the flow divider / combiner valve, directing the hydraulic oil to flow into the front axle motor and the rear axle motor in parallel, includes: If the plunger pump moves in the forward direction, the first port of the shuttle valve in the flow divider and combiner valve is opened, and the first port of the two-position three-way solenoid valve in the flow divider and combiner valve is controlled to be in the spring position, thereby disconnecting both ends of the first reversing valve, opening both ends of the second reversing valve, disconnecting both ends of the third reversing valve, and opening both ends of the fourth reversing valve in the flow divider and combiner valve. The hydraulic oil passes through the first port of the balance valve in the flow divider and combiner valve, and is then divided into a first oil path and a second oil path through the second and third ports. The first oil flows into the first port of the front axle motor, flows out from the second port of the front axle motor to the first port of the fourth directional valve, and flows out from the second port of the fourth directional valve; The second oil flows into the first port of the second reversing valve, flows out from the second port of the second reversing valve to the second port of the rear axle motor, and flows out from the first port of the rear axle motor.

4. The method according to claim 3, characterized in that, The method of controlling the valve direction of the flow divider and combiner valve to direct the hydraulic oil into the front axle motor and the rear axle motor in parallel also includes: If the plunger pump moves in the reverse direction, the second port of the shuttle valve in the flow divider and combiner valve is opened, and the first port of the two-position three-way solenoid valve in the flow divider and combiner valve is controlled to be in the spring position, thereby disconnecting both ends of the first reversing valve, opening both ends of the second reversing valve, disconnecting both ends of the third reversing valve, and opening both ends of the fourth reversing valve in the flow divider and combiner valve. The hydraulic oil is divided into a first oil path and a second oil path. The first oil path flows into the second port of the fourth directional valve, flows out from the first port of the fourth directional valve to the second port of the front axle motor, and flows out from the first port of the front axle motor. The second oil flows into the first port of the rear axle motor, flows out from the second port of the rear axle motor to the second port of the second reversing valve, and flows out from the first port of the second reversing valve; The second oil flowing out from the first port of the second directional valve flows into the second port of the balance valve, and the first oil flowing out from the first port of the front axle motor flows into the third port of the balance valve, and then flows out through the first port of the balance valve to merge into one hydraulic oil.

5. The method according to claim 3, characterized in that, The control of the valve direction of the flow divider / combiner valve, directing the hydraulic oil into the front axle motor and the rear axle motor in series, includes: If the plunger pump moves in the forward direction, the first port of the shuttle valve in the flow divider and combiner valve is opened, and the first port of the two-position three-way solenoid valve in the flow divider and combiner valve is controlled to be in the solenoid valve position, so that the two ends of the first reversing valve in the flow divider and combiner valve are opened, the two ends of the second reversing valve are closed, the two ends of the third reversing valve are opened, and the two ends of the fourth reversing valve are closed. The hydraulic oil passes through the first port of the balance valve in the flow divider and combiner valve, and is then divided into a first oil path and a second oil path through the second and third ports. The second oil flows into the second port of the first reversing valve, flows out from the first port of the first reversing valve, and flows together with the first oil into the first port of the front axle motor. It then flows out from the second port of the front axle motor to the second port of the third reversing valve, and from the first port of the third reversing valve to the second port of the rear axle motor, and finally flows out from the first port of the rear axle motor.

6. The method according to claim 3, characterized in that, The control of the valve direction of the flow divider / combiner valve, directing the hydraulic oil into the front axle motor and the rear axle motor in series, includes: If the plunger pump moves in the reverse direction, the second port of the shuttle valve in the flow divider and combiner valve is opened, and the first port of the two-position three-way solenoid valve in the flow divider and combiner valve is controlled to be in the solenoid valve position, so that the two ends of the first reversing valve in the flow divider and combiner valve are opened, the two ends of the second reversing valve are closed, the two ends of the third reversing valve are opened, and the two ends of the fourth reversing valve are closed. The hydraulic oil flows into the first port of the rear axle motor, flows out from the second port of the rear axle motor to the first port of the third directional valve, flows out from the second port of the third directional valve to the second port of the front axle motor, flows out from the first port of the front axle motor to the second port of the balance valve, or flows into the third port of the balance valve after passing through the first directional valve, and flows out from the first port of the balance valve.

7. A hydrostatic loader, characterized in that, The hydraulic walking system includes any one of claims 1 to 2.

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