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

Abstract

The invention relates to the technical field of engineering machinery, and discloses a hydraulic walking system, a control method of the hydraulic walking system and a hydrostatic loader, the hydraulic walking system comprises a plunger pump, a front axle motor, a rear axle motor and a flow distributing and collecting valve; the plunger pump is used for performing forward movement or reverse movement based on the hydraulic oil; the flow distributing and collecting valve is connected with the plunger pump and used for adjusting the flowing direction of the hydraulic oil, so that the hydraulic oil flows into the front axle motor and the rear axle motor in a parallel connection or series connection mode; the front axle motor and the rear axle motor are connected with the flow distributing and collecting valve and used for converting hydraulic energy of the hydraulic oil into mechanical energy. Forward and reverse rotation of hydraulic walking and series-parallel connection of motors can be achieved, the flowing direction of hydraulic oil is flexibly adjusted, and therefore different walking speeds and traction force are provided, and the small hydrostatic loading machine can normally operate under different working conditions.

Description

Technical Field

[0001] The present invention relates to the technical field of engineering machinery, and in particular to a hydraulic travel system, a control method of the hydraulic travel system and a static hydraulic loader. Background Art

[0002] Travel speed and traction are the core performance of small hydrostatic loaders, which are directly related to the working efficiency of the whole machine and the ability to get out of trouble after being stuck. At present, small hydrostatic models are usually equipped with a single-displacement piston pump and double-cycloid motor system travel hydraulic system, including a piston pump, a front axle motor and a rear axle motor, such as Figure 1 As shown, the hydraulic oil is discharged from port A of the plunger pump, passes through port B1 of the rear axle motor to port A1, and then enters port B2 of the front axle motor to port A2. Port A2 discharges oil to port B of the plunger pump to complete the cycle. The hydraulic oil passes through the front and rear motors in succession, and the two motors are connected in series. At this time, the whole machine has only one travel speed and output torque. Therefore, in order to ensure normal operation, the whole machine can only choose to connect the front and rear motors in series to keep the whole machine at a high speed. At this time, the use of the motor is limited, the output torque is small, and the traction is small. When the whole machine is in trouble, it is not easy to get out of trouble due to the small traction. Summary of the invention

[0003] In view of this, the present invention provides a hydraulic travel system, a control method of the hydraulic travel system and a static hydraulic loader to solve the problem that the hydraulic travel system is restricted.

[0004] In the first aspect, the present invention provides a hydraulic travel system, including: a plunger pump, a front axle motor, a rear axle motor and a diverter and collector valve; the plunger pump is used to perform forward or reverse movement based on hydraulic oil; the diverter and collector 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 in series; the front axle motor and the rear axle motor are connected to the diverter and collector valve to convert the hydraulic energy of the hydraulic oil into mechanical energy.

[0005] The hydraulic travel system provided by the present invention, by arranging a diverter and collector valve between the plunger pump and the front and rear axle motors, the diverter and collector valve adjusts the flow direction of the hydraulic oil flowing out of the plunger pump in the forward or reverse movement, so that the hydraulic oil flows into the front axle motor and the rear axle motor in parallel or in series, and can realize the forward and reverse rotation of hydraulic travel and the series and parallel connection of the motors, and flexibly adjust the flow direction of the hydraulic oil, thereby providing different travel speeds and traction forces, so that the small hydrostatic loader can operate normally under different working conditions.

[0006] In an optional embodiment, the flow diversion and collection valve includes: a shuttle valve, a balancing valve, a two-position three-way solenoid valve and a directional control valve; the shuttle valve, the two ends of which are respectively connected to the two ends of the plunger pump, for controlling the forward movement direction or the reverse movement direction of the hydraulic oil; the balancing valve, the first port of which is connected to the first port of the plunger pump, the second port and the third port of which are respectively connected to the first port and the second port of the directional control valve, for evenly distributing the hydraulic oil input from the first port into the first oil and the second oil, or combining the first oil and the second oil input from the second port and the third port into one; the two-position three-way solenoid valve, the first end of which is connected to the third port of the shuttle valve, the second port of which is 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, the first port and the second port of which are respectively connected to the two ends of the front axle motor or the rear axle motor, for controlling the flow direction of the first oil and the second oil based on the conduction direction, and flowing the first oil and the second oil into the front axle motor and the rear axle motor in parallel or in series.

[0007] The present invention deploys a shuttle valve, a balancing valve, a two-position three-way solenoid valve and a directional control valve in a specific connection mode, thereby being able to control the flow direction of the hydraulic oil and evenly distribute it into two paths, thereby realizing parallel and series connection of the front and rear motors, and further realizing high and low speed control and anti-rotation control of the front and rear motors.

[0008] In an optional embodiment, the directional control valve includes: a first reversing valve, a second reversing valve, a third reversing valve and a fourth reversing valve connected in sequence, wherein the first port of the first reversing valve is connected to the second port of the balancing valve and the first port of the front axle motor, and the second port is connected to the third port of the balancing 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.

[0009] The present invention deploys multiple steering valves to input two lines of hydraulic oil into the front and rear axle motors in series or parallel, providing different walking speeds and traction forces for the small hydrostatic loader, so that it can operate normally under different working conditions.

[0010] In an optional implementation, the directional control valve is any one of a switch quantity electromagnetic directional control valve, a proportional quantity electromagnetic directional control valve, a hydraulically controlled directional control valve or a manual directional control valve.

[0011] The present invention deploys a steering valve and can control the valve inside the steering valve to achieve the conduction or disconnection of the hydraulic oil, thereby providing different flow directions, so that the hydraulic oil flows into the front and rear axle motors in parallel or in series.

[0012] In a second aspect, the present invention provides a control method for a hydraulic travel system, the hydraulic travel system comprising a plunger pump, a flow divider and flow collector valve, a front axle motor and a rear axle motor, wherein the plunger pump is connected to the front axle motor and the rear axle motor through the flow divider and flow collector valve, and the control method for the hydraulic travel system comprises:

[0013] According to the working state, the plunger pump is controlled to press the hydraulic oil into the flow dividing and collecting valve in the forward or reverse motion mode;

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

[0015] The hydraulic oil from the front axle motor and the rear axle motor is sucked into the piston pump according to the forward or reverse operation.

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

[0017] In an optional embodiment, the flow diversion and collection valve includes: a shuttle valve, a balancing valve, a two-position three-way solenoid valve and a directional control valve, and the directional control valve includes: a first reversing valve, a second reversing valve, a third reversing valve and a fourth reversing valve, wherein the two ends of the shuttle valve are respectively connected to the two ends of the plunger pump; the first port of the balancing valve is connected to the first port of the plunger pump, and the second port and the third port are respectively connected to the first port and the second port of the first reversing valve; 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 directional control valve; 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 end of the plunger pump The valve direction of the diverter and collector valve is controlled to flow the hydraulic oil into the front axle motor and the rear axle motor in parallel, including: if the plunger pump moves in the forward direction, the first port of the shuttle valve in the diverter and collector valve is connected, and the first port of the two-position three-way solenoid valve in the diverter and collector valve is controlled to be in the spring position, the two ends of the first steering valve in the diverter and collector valve are disconnected, the two ends of the second steering valve are connected, the two ends of the third steering valve are disconnected, and the two ends of the fourth steering valve are connected; the hydraulic oil passes through the first port of the balancing valve in the diverter and collector valve, and is divided into the first oil and the second oil through the second port and the third port; 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 steering valve, and flows out from the second port of the fourth steering valve; the second oil flows into the first port of the second steering valve, flows out from the second port of the second steering valve to the second port of the rear axle motor, and flows out from the first port of the rear axle motor.

[0018] The present invention controls the hydraulic oil to flow out in a forward motion manner and simultaneously flow into the front and rear axle motors in parallel, thereby ensuring that the motors rotate or move at a low speed. At this time, the motors output a large torque and the entire machine moves forward with a large traction force.

[0019] In an optional embodiment, the valve direction of the flow-dividing and collecting valve is controlled to make the hydraulic oil flow into the front axle motor and the rear axle motor in parallel, and further includes: if the plunger pump moves in the reverse direction, the second port of the shuttle valve in the flow-dividing and collecting valve is connected, and the first port of the two-position three-way solenoid valve in the flow-dividing and collecting valve is controlled to be in the spring position, the two ends of the first steering valve in the flow-dividing and collecting valve are disconnected, the two ends of the second steering valve are connected, the two ends of the third steering valve are disconnected, and the two ends of the fourth steering valve are connected; 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 steering valve, flows out from the first port of the fourth steering 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 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 steering valve, and flows out from the first port of the second steering valve; the second oil path flowing out of the first port of the second steering valve flows into the second port of the balancing valve, the first oil path flows out from the first port of the front axle motor into the third port of the balancing valve, and flows out through the first port of the balancing valve to form a hydraulic oil path.

[0020] The present invention controls the hydraulic oil to flow out in a reverse motion manner and simultaneously flow into the front and rear axle motors in parallel, thereby ensuring that the motors rotate or move in the reverse direction at a low speed. At this time, the motors output a large torque and the whole machine moves backward with a large traction force.

[0021] In an optional embodiment, the valve direction of the diverter and collector valve is controlled to make the hydraulic oil flow into the front axle motor and the rear axle motor in series, including: if the plunger pump moves in the forward direction, the first port of the shuttle valve in the diverter and collector valve is connected, and the first port of the two-position three-way solenoid valve in the diverter and collector valve is controlled to be in the solenoid valve position, the two ends of the first steering valve in the diverter and collector valve are connected, the two ends of the second steering valve are disconnected, the two ends of the third steering valve are connected, and the two ends of the fourth steering valve are disconnected; the hydraulic oil passes through the first port of the balancing valve in the diverter and collector valve, and is divided into the first oil path and the second oil path through the second port and the third port; the second oil path flows into the second port of the first steering valve, flows out from the first port of the second steering valve and then flows into the first port of the front axle motor together with the first oil path, flows out from the second port of the front axle motor to the second port of the third steering valve, and flows out from the first port of the third steering valve to the second port of the rear axle motor, and flows out from the first port of the rear axle motor.

[0022] The present invention controls the hydraulic oil to flow out in a forward motion manner and successively flow into the front and rear axle motors in a series manner, thereby ensuring that the motors rotate or move at a high speed, and the entire vehicle moves forward at a high speed.

[0023] In an optional embodiment, the valve direction of the diverter and collector valve is controlled to make the hydraulic oil flow into the front axle motor and the rear axle motor in series, including: if the plunger pump moves in the reverse direction, the second port of the shuttle valve in the diverter and collector valve is connected, and the first port of the two-position three-way solenoid valve in the diverter and collector valve is controlled to be in the solenoid valve position, the two ends of the first steering valve in the diverter and collector valve are connected, the two ends of the second steering valve are disconnected, the two ends of the third steering valve are connected, and the two ends of the fourth steering valve are disconnected; 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 steering valve, flows out from the second port of the third steering 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 balancing valve, or flows into the third port of the balancing valve after passing through the first steering valve, and flows out from the first port of the balancing valve.

[0024] The present invention controls the hydraulic oil to flow out in a reverse motion manner and successively flow into the front and rear axle motors in a series manner, thereby ensuring that the motors rotate or move in the reverse direction at a high speed, and at this time the entire vehicle moves backward at a high speed.

[0025] In a third aspect, the present invention provides a static hydraulic loader, comprising the hydraulic travel system of the first aspect or any corresponding embodiment thereof. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0027] Figure 1 is a structural block diagram of a walking hydraulic system of a single-fixed displacement plunger pump and double-cycloid motor system according to an embodiment of the present invention;

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

[0029] Figure 3 is a flow chart of a control method of a hydraulic travel system according to an embodiment of the present invention;

[0030] Figure 4 2 is a schematic diagram of a parallel connection of a control method for a hydraulic travel system according to an embodiment of the present invention;

[0031] Figure 5 is a flow chart of another control method of a hydraulic travel system according to an embodiment of the present invention;

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

[0033] Description of the accompanying drawings: 100 - plunger pump; 200 - flow diversion and collection valve; 201 - shuttle valve; 202 - balancing valve; 203 - two-position three-way solenoid valve; 204 - first reversing valve; 205 - second reversing valve; 206 - third reversing valve; 207 - fourth reversing valve; 301 - front axle motor; 302 - rear axle motor. DETAILED DESCRIPTION

[0034] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present invention.

[0035] The embodiment of the present invention is applicable to the application scenario of controlling the hydraulic travel system of a small hydrostatic loader according to working conditions. Figure 1 As shown, in the single-quantity plunger pump double-cycloid motor system walking hydraulic system currently configured for small hydrostatic models, the hydraulic oil is discharged through the A port of the pump, passes through the B1 oil port of the rear motor to the A1 oil port, and then enters the B2 oil port of the front motor to the A2 oil port. The A2 oil port is discharged to the B port of the pump to complete the cycle. The hydraulic oil passes through the front and rear motors in turn, and the two motors are connected in series. At this time, the whole machine has only one walking speed and traction, and its use will be limited. Therefore, an embodiment of the present invention provides a hydraulic walking system, which achieves the effect of flexibly adjusting the flow direction of the hydraulic oil in the hydraulic walking system by deploying a diverter and collector valve.

[0036] According to an embodiment of the present invention, a hydraulic travel system embodiment is provided. Figure 2 is a structural block diagram of a hydraulic travel system according to an embodiment of the present invention. Figure 2 As shown, the system includes: a plunger pump 100, a diverter and collector valve 200, a front axle motor 301 and a rear axle motor 302; the plunger pump 100 is used to perform forward or reverse movement based on hydraulic oil; the diverter and collector valve 200 is connected to the plunger pump 100 and 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 in series; the front axle motor 301 and the rear axle motor 302 are connected to the diverter and collector valve 200 and are used to convert the hydraulic energy of the hydraulic oil into mechanical energy.

[0037] Specifically, in the embodiment of the present invention, Figure 2As shown, the flow dividing and collecting valve 200 includes: a shuttle valve 201, a balancing valve 202, a two-position three-way solenoid valve 203 and a directional control valve, and the directional control valve includes: a first reversing valve 204, a second reversing valve 205, a third reversing valve 206 and a fourth reversing valve 207 connected in sequence, and four oil ports are formed after being connected to each other through the directional control valves: A1, A2, B1 and B2. M1 and M2 are the oil ports of the front axle motor 301, and they are the oil inlet and return ports of each other; M3 and M4 are the oil ports of the rear axle motor 302, and they are the oil inlet and return ports of each other. Port A and port B are the oil ports of the plunger pump, and they are the oil inlet and return ports of each other. If the oil enters from port A and returns from port B, it is a forward movement, and if the oil enters from port B and returns from port A, it is a reverse movement.

[0038] In some optional embodiments, such as Figure 2 As shown, in the flow dividing and collecting valve 200 of the embodiment of the present invention, 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 movement direction or reverse movement direction of the hydraulic oil. The first port of the balancing valve 202 is connected to the first port A of the plunger pump 100, and the second port and the third port are respectively connected to the first port a1 and the second port a2 of the first reversing valve 204, for evenly distributing the hydraulic oil input from the first port into the first oil and the second oil, or combining the first oil and the second oil input from the second port and the third port into one oil. 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 reversing valve 204, the second reversing valve 205, the third reversing valve 206 and the fourth reversing valve 207, for adjusting the conduction direction of the first reversing valve 204, the second reversing valve 205, the third reversing valve 206 and the fourth reversing valve 207. The directional control valve 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 parallel or in series.

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

[0040] In some optional embodiments, the flow dividing and collecting valve 200 switches different oil circuits through the action of the solenoid valve, so that the high-pressure hydraulic oil entering the A port or the B port flows out from different outlets according to the demand, so as to achieve the purpose of controlling the series and parallel connection of the front and rear axle motors, and then realize the torque switching. Among them, in the parallel form, the two loads of the front axle motor 301 and the rear axle motor 302 evenly distribute the oil inlet flow of the oil ports A1, A2 or B1, B2, and the hydraulic oil of the oil ports A1, A2 or B1, B2 enters the front and rear motors at the same time without any order difference; in the series form, the hydraulic oil entering the element through A1 or B2 passes through the front axle motor 301 and the rear axle motor 302 in turn, and the order is confirmed according to the specific oil inlet.

[0041] In some optional embodiments, the working principle of the shuttle valve 201 mainly relies on the up and down movement of the valve core on the valve seat to control the flow of the medium, thereby achieving regulation and control of the fluid. Specifically, when the actuator applies force to move the valve core up and down, the size of the gap between the valve core and the valve seat will change, thereby affecting the flow of the medium. When the valve core rises, the gap becomes larger and the medium can pass smoothly; when the valve core falls, the gap becomes smaller and the flow of the medium is restricted. In an embodiment of the present invention, the shuttle valve 201 is connected to port A or port B through the up and down movement of the valve core, thereby achieving forward and reverse rotation of the hydraulic travel system.

[0042] In some optional embodiments, the working principle of the balancing valve 202 is to change the gap (opening) between the valve core and the valve seat, thereby changing the flow resistance flowing through the valve to achieve the purpose of regulating the flow. This regulation targets the resistance of the system, and can make the hydraulic oil distributed in a balanced manner according to the designed calculated ratio, ensuring that each branch can still meet the flow demand under partial load, thereby playing a balancing role. The embodiment of the present invention divides the hydraulic oil into two paths evenly through the balancing valve 202.

[0043] In some optional embodiments, the working principle of the two-position three-way solenoid valve 203 mainly includes two aspects: electromagnetic principle and mechanical principle. The electromagnetic principle is to control the opening and closing of the valve by the attraction and release of the electromagnet. When the electromagnet is energized, a magnetic field is generated to attract the iron core, thereby opening the valve; when the electromagnet is de-energized, the iron core loses its magnetism and the valve is closed. The mechanical principle is to control 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 the spring, and the flow direction of the medium is restored. This is just an example and is not limited to this. Figure 2 As shown in FIG. 1 , in the embodiment of the present invention, the first position of the two-position three-way solenoid valve 203 is located at the lower side, and the second position of the solenoid valve is located at the upper side, thereby realizing the conduction between the shuttle valve 201 and each steering valve, so that the control oil flowing from the shuttle valve 201 into the steering valve through the two-position three-way solenoid valve 203 is adjusted to adjust the conduction state of the steering valve, wherein the flow direction of the control oil is as shown in FIG. Figure 2 Shown by the dashed line.

[0044] In some optional embodiments, the working principle of the directional control valve is to change the flow direction of the hydraulic oil flow through the relative movement of the valve core in the valve body, thereby realizing the change of the movement direction of the actuator. The directional control valve has more than two flow forms and more than two oil ports, and mainly realizes the communication, cutting and reversing of the hydraulic oil flow, as well as pressure unloading and sequential action control through the relative movement of the valve core and the valve body. The directional control valve can be set as a directional control valve with various operating forms such as a switch electromagnetic directional control valve, a proportional electromagnetic directional control valve, a hydraulically controlled directional control valve and a manual directional control valve, as examples only, and not limited to this. Figure 2 As shown, the directional control valve of the embodiment of the present invention includes a one-way valve and a steering valve, and the conduction of the one-way valve or the two-way valve is achieved by controlling the oil. The specific conduction condition is determined according to the working state of the hydraulic travel system.

[0045] The hydraulic travel system provided by the present invention arranges a diverter and collector valve between the plunger pump and the front and rear axle motors, and the diverter and collector valve adjusts the flow direction of the hydraulic oil flowing out of the plunger pump during forward or reverse movement, so that the hydraulic oil flows into the front axle motor and the rear axle motor in parallel or in series, and can realize the forward and reverse rotation of hydraulic travel and the series and parallel connection of the motors, and flexibly adjust the flow direction of the hydraulic oil, thereby providing different travel speeds and traction forces, so that the small hydrostatic loader can operate normally under different working conditions, and various solenoid valves are integrated into a diverter and collector valve, so that the system has a small size, a high degree of integration, and is easy to operate, and the control methods include electronic control, hydraulic control, manual control, etc.

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

[0047] In this embodiment, a control method for a hydraulic travel system is provided, which can be used in the above Figure 2 The hydraulic travel system shown, Figure 3 : is a flow chart of a control method of a hydraulic travel system according to an embodiment of the present invention. Figure 3 As shown, the process includes the following steps:

[0048] Step S301, according to the working state, the plunger pump is controlled to pressurize hydraulic oil into the flow dividing and combining valve in a forward or reverse motion.

[0049] Step S302, controlling the valve direction of the flow dividing and collecting valve to allow the 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 sucked into the plunger pump in a forward motion or reverse motion manner.

[0051] Specifically, in an embodiment of the present invention, when the hydrostatic loader is in working or escape condition, if A is in working state, the plunger pump moves in the forward direction, that is, the hydraulic oil flows out from port A, and after the hydraulic oil flows into the shuttle valve, the valve core of the shuttle valve is moved downward, so that the first port and the third port of the shuttle valve are connected, and 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 controlled to be in the spring position by powering off the switch, so that the two ends of the first steering valve are disconnected, the two ends of the second steering valve are connected, the two ends of the third steering valve are disconnected, and the two ends of the fourth steering valve are connected. At this time, the a1 port of the first steering valve is connected to the A1 oil port, the a1 port of the first steering valve is not connected to the a2 port of the first steering valve, the a3 port of the second steering valve is connected to the a4 port of the second steering valve, the a4 port of the second steering valve and the a5 port of the third steering valve are connected to the A2 oil port, the a5 port of the third steering valve is not connected to the a6 port of the third steering valve, the B1 oil port is connected to the a7 port of the fourth steering valve and the a8 port of the fourth steering valve, the B2 oil port is connected to the a8 port of the fourth steering valve, and the conduction condition 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 balancing valve in the flow dividing and collecting valve, and is divided into the first oil and the second oil through the second port and the third port; the first oil 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 oil 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, and the hydraulic oil flowing out of a8 and M3 flows into port B of the plunger pump at the same time. At this time, the front and rear axle motors are in parallel, and the motors rotate or move at a low speed. At this time, the motors have a large torque output, and the whole machine moves forward with a large traction force.

[0052] In some optional embodiments, when the hydrostatic loader is in operation or in an escape condition, if B is in operation, the plunger pump moves in the reverse direction, that is, the hydraulic oil flows out from the B port, and after the hydraulic oil flows into the shuttle valve, the valve core of the shuttle valve is moved upward, so that the second port of the shuttle valve is connected to the third port, and 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 controlled to be in the spring position by powering off the switch, so that the two ends of the first steering valve are disconnected, the two ends of the second steering valve are connected, the two ends of the third steering valve are disconnected, and the two ends of the fourth steering valve are connected. At this time, the a1 port of the first steering valve is connected to the A1 oil port, the a1 port of the first steering valve is not connected to the a2 port of the first steering valve, the a3 port of the second steering valve is connected to the a4 port of the second steering valve, the a4 port of the second steering valve and the a5 port of the third steering valve are connected to the A2 oil port, the a5 port of the third steering valve is not connected to the a6 port of the third steering valve, the B1 oil port is connected to the a7 port of the fourth steering valve and the a8 port of the fourth steering valve, the B2 oil port is connected to the a8 port of the fourth steering valve, and the conduction condition of the hydraulic travel system is as follows: Figure 4 As shown. The hydraulic oil flowing out of port B is divided into the first oil and the second oil. The first oil 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 flows out from the first port M1 of the front axle motor; the second oil 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 flows out from the first port a3 of the second steering valve; the second oil flowing out of 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 flows out through the first port of the balance valve to merge into one hydraulic oil, and flows into port A of the plunger pump. At this time, the front and rear axle motors are in parallel, and the motors rotate or move in the reverse direction at a low speed. At this time, the motors have a large torque output, and the whole machine has a large traction force to move backward.

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

[0054] In this embodiment, a control method for a hydraulic travel system is provided, which can be used in the above Figure 2 The hydraulic travel system shown, Figure 5 : is a flow chart of a control method of a hydraulic travel system according to an embodiment of the present invention. Figure 5 As shown, the process includes the following steps:

[0055] Step S501, according to the working state, the plunger pump is controlled to pressurize hydraulic oil into the flow dividing and combining valve in a forward or reverse motion.

[0056] Step S502, controlling the valve direction of the flow dividing and collecting valve to allow the 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 sucked into the plunger pump in a forward motion or reverse motion mode.

[0058] Specifically, in an embodiment of the present invention, when the hydrostatic loader is in a transfer condition, if A is in a working state, the plunger pump moves in a forward direction, that is, the hydraulic oil flows out from port A, and after the hydraulic oil flows into the shuttle valve, the valve core of the shuttle valve is moved downward, so that the first port and the third port of the shuttle valve are connected, and 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 through the switch control, so that the two ends of the first steering valve are connected, the two ends of the second steering valve are disconnected, the two ends of the third steering valve are connected, and the two ends of the fourth steering valve are disconnected. At this time, the a1 port of the first steering valve is connected to the A1 oil port, the a1 port of the first steering valve is connected to the a2 port of the first steering valve, the a3 port of the second steering valve is not connected to the a4 port of the second steering valve, the A2 oil port is connected to the a5 port of the third steering valve and the a6 port of the third steering valve, the B1 oil port is connected to the a6 port of the third steering valve, the a7 port of the fourth steering valve is not connected to the a8 port of the fourth steering valve, and the B2 oil port is connected to the a8 port of the fourth steering valve. The conduction condition of the hydraulic travel system is as follows: Figure 6 As shown. The hydraulic oil flowing out from port A passes through the first port of the balancing valve in the flow dividing and collecting valve, and is divided into the first oil and the second oil through the second port and the third port; the second oil flows into the second port a2 of the first steering valve, flows out from the first port a1 of the first steering valve and flows into the first port M1 of the front axle motor together with the first oil, flows out from the second port M2 of the front axle motor to the second port a6 of the third steering valve, and flows out from the first port a5 of the third 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 and flows into the port B of the plunger pump. At this time, the front and rear motors are in series, the motors rotate or move at high speed, and the whole vehicle moves forward at high speed.

[0059] In some optional embodiments, when the hydrostatic loader is in a transfer condition, if B is in working condition, the plunger pump moves in the reverse direction, that is, the hydraulic oil flows out from the B port, and after the hydraulic oil flows into the shuttle valve, the valve core of the shuttle valve is moved upward, so that the second port and the third port of the shuttle valve are connected, and 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 through the switch control, so that the two ends of the first steering valve are connected, the two ends of the second steering valve are disconnected, the two ends of the third steering valve are connected, and the two ends of the fourth steering valve are disconnected. At this time, the a1 port of the first steering valve is connected to the A1 oil port, the a1 port of the first steering valve is connected to the a2 port of the first steering valve, the a3 port of the second steering valve is not connected to the a4 port of the second steering valve, the A2 oil port is connected to the a5 port of the third steering valve and the a6 port of the third steering valve, the B1 oil port is connected to the a6 port of the third steering valve, the a7 port of the fourth steering valve is not connected to the a8 port of the fourth steering valve, and the B2 oil port is connected to the a8 port of the fourth steering valve. The conduction condition of the hydraulic travel system is as follows: Figure 6 As shown. The hydraulic oil flowing out of port B 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 first port a5 of the third steering valve, flows out from the second port a6 of the third steering valve to the second port M2 of the front axle motor, flows out from the first port M1 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 steering valve, and flows out from the first port of the balance valve to the A port of the plunger pump. At this time, the front and rear motors are in series, and the motors rotate or move in the opposite direction at high speed. At this time, the whole vehicle is moving backward at a high speed.

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

[0061] The present invention also provides a static hydraulic loader, comprising: Figure 2 Hydraulic travel system shown.

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

Claims

1. A hydraulic travel system, comprising a plunger pump, a front axle motor and a rear axle motor, characterized in that: The system further comprises: a flow dividing and combining valve; The plunger pump is used to perform forward or reverse movement based on hydraulic oil; The flow dividing and combining 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 in series; The front axle motor and the rear axle motor are connected to the flow dividing and combining valve, and are used to convert the hydraulic energy of the hydraulic oil into mechanical energy.

2. The system according to claim 1, characterized in that The flow dividing and collecting valve comprises: a shuttle valve, a balancing 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 the plunger pump respectively, and is used to control the forward movement direction or the reverse movement direction of the hydraulic oil; The balancing valve has a first port connected to the first port of the plunger pump, and a second port and a third port connected to the first port and the second port of the directional control valve, respectively, for evenly distributing the hydraulic oil input from the first port 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 port and the third port 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, and is used to adjust the conduction direction of the directional control valve; The directional control valve, the first port and the second port are respectively connected to the two ends of the front axle motor or the rear axle motor, and are 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 form or the series form.

3. The system according to claim 2, characterized in that The directional control valve comprises: a first reversing valve, a second reversing valve, a third reversing valve and a fourth reversing valve connected in sequence, wherein: The first port of the first reversing valve is connected to the second port of the balancing valve and the first port of the front axle motor, and the second port is connected to the third port of the balancing 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.

4. The system according to claim 3, characterized in that The directional control valve is any one of a switch quantity electromagnetic directional control valve, a proportional quantity electromagnetic directional control valve, a hydraulically controlled directional control valve or a manual directional control valve.

5. A control method for a hydraulic travel system, characterized in that: The hydraulic travel system includes a plunger pump, a flow divider and flow collector valve, a front axle motor and a rear axle motor, wherein the plunger pump is connected to the front axle motor and the rear axle motor through the flow divider and flow collector valve, and the control method of the hydraulic travel system includes: Control the plunger pump to press hydraulic oil into the flow dividing and collecting valve in a forward or reverse motion according to the working state; Controlling the valve direction of the flow dividing and combining valve to allow the hydraulic oil to flow into the front axle motor and the rear axle motor in parallel or in series; The hydraulic oil flowing out of the front axle motor and the rear axle motor is sucked into the plunger pump in the forward motion or the reverse motion.

6. The method according to claim 5, characterized in that The flow dividing and collecting valve includes: a shuttle valve, a balancing valve, a two-position three-way solenoid valve and a directional control valve, and the directional control valve includes: a first reversing valve, a second reversing valve, a third reversing valve and a fourth reversing valve, wherein: The two ends of the shuttle valve are respectively connected to the two ends of the plunger pump; the first port of the balancing valve is connected to the first port of the plunger pump, and the second port and the third port are respectively connected to the first port and the second port of the first reversing valve; 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 method of controlling the valve direction of the flow dividing and collecting valve to flow the hydraulic oil 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-dividing and collecting valve is connected, and the first port of the two-position three-way solenoid valve in the flow-dividing and collecting valve is controlled to be in the spring position, so that the two ends of the first steering valve in the flow-dividing and collecting valve are disconnected, the two ends of the second steering valve are connected, the two ends of the third steering valve are disconnected, and the two ends of the fourth steering valve are connected; The hydraulic oil passes through the first port of the balancing valve in the flow dividing and collecting valve, and is divided into a first oil path and a second oil path through the second port and the third port; 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 steering valve, and flows out from the second port of the fourth steering valve; The second oil path flows into the first port of the second steering valve, flows out from the second port of the second steering valve to the second port of the rear axle motor, and flows out from the first port of the rear axle motor.

7. The method according to claim 6, characterized in that The control of the valve direction of the flow dividing and collecting valve to flow 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-dividing and collecting valve is connected, and the first port of the two-position three-way solenoid valve in the flow-dividing and collecting valve is controlled to be in the spring position, so that the two ends of the first steering valve in the flow-dividing and collecting valve are disconnected, the two ends of the second steering valve are connected, the two ends of the third steering valve are disconnected, and the two ends of the fourth steering valve are connected; The hydraulic oil is divided into the first oil path and the second oil path, the first oil path flows into the second port of the fourth steering valve, flows out from the first port of the fourth steering 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 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 steering valve, and flows out from the first port of the second steering valve; The second oil flowing out from the first port of the second steering valve flows into the second port of the balancing valve, the first oil flowing out from the first port of the front axle motor flows into the third port of the balancing valve, and flows out through the first port of the balancing valve to merge into one path of hydraulic oil.

8. The method according to claim 6, characterized in that The control of the valve direction of the flow dividing and collecting valve to flow 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-dividing and collecting valve is connected, and the first port of the two-position three-way solenoid valve in the flow-dividing and collecting valve is controlled to be in the solenoid valve position, so that the two ends of the first steering valve in the flow-dividing and collecting valve are connected, the two ends of the second steering valve are disconnected, the two ends of the third steering valve are connected, and the two ends of the fourth steering valve are disconnected; The hydraulic oil passes through the first port of the balancing valve in the flow dividing and collecting valve, and is divided into a first oil path and a second oil path through the second port and the third port; The second oil flows into the second port of the first steering valve, flows out from the first port of the first steering valve and then flows into the first port of the front axle motor together with the first oil, flows out from the second port of the front axle motor to the second port of the third steering valve, flows out from the first port of the third steering valve to the second port of the rear axle motor, and flows out from the first port of the rear axle motor.

9. The method according to claim 6, characterized in that The control of the valve direction of the flow dividing and collecting valve to flow 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-dividing and collecting valve is connected, and the first port of the two-position three-way solenoid valve in the flow-dividing and collecting valve is controlled to be in the solenoid valve position, so that the two ends of the first steering valve in the flow-dividing and collecting valve are connected, the two ends of the second steering valve are disconnected, the two ends of the third steering valve are connected, and the two ends of the fourth steering valve are disconnected; 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 steering valve, flows out from the second port of the third steering 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 balancing valve, or flows into the third port of the balancing valve after passing through the first steering valve, and flows out from the first port of the balancing valve.

10. A hydrostatic loader, characterized in that: A hydraulic travel system comprising any one of claims 1 to 4.

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