A skid steer loader hydraulic system, method of controlling the same, and skid steer loader

Abstract

This invention discloses a hydraulic system for a skid steer loader, its control method, and the skid steer loader itself. In the hydraulic system, the outlet of the travel pump is connected to the inlets of the first and second travel motors. The control oil outlet of the travel pump is connected to the inlets of the left and right hydraulic pilot handles via a first solenoid directional valve. The four control oil circuits (front, rear, left, and right) of the left hydraulic pilot handle are connected to the travel pump and a multi-way valve via a left handle oil circuit switching valve. The two control oil circuits (left and right) of the right hydraulic pilot handle are connected to the multi-way valve, and the two control oil circuits (front and rear) of the right hydraulic pilot handle are connected to the travel pump and the multi-way valve via a right handle oil circuit switching valve. This invention retains the sensitive and convenient operation of the hydraulic pilot control while providing both ISO and H operating modes, allowing users to switch freely according to their needs. This enhances the adaptability of the machine to different working conditions, improves work efficiency, and offers cost advantages.

Description

Technical Field

[0001] This invention belongs to the field of hydraulic system technology, specifically relating to a skid steer loader hydraulic system, its control method, and the skid steer loader. Background Technology

[0002] A skid steer loader is a wheeled, specialized chassis-mounted machine that uses the difference in linear speed between its two wheels to achieve steering. It is primarily used in situations with limited space, uneven terrain, and frequently changing tasks. To meet diverse operating conditions, skid steer loaders are equipped with various implements, such as sweepers, milling machines, and snow blowers. Each implement places different demands on the overall machine's control.

[0003] There are generally three types of control methods for skid steer loaders: mechanical control, electronic control, and hydraulic pilot control. Specifically:

[0004] (1) Mechanical operation is divided into hand and foot operation and hand-only operation. Its characteristics are low cost, but large operating force and high labor intensity for drivers during long-term operation;

[0005] (2) The electric control is a dual-handle control, usually divided into two modes: H mode and ISO mode. The electric control is usually based on the controller to easily switch between H mode and ISO mode to cope with different working tools and working conditions. Its characteristics are sensitive operation and high degree of customization, but the system cost is high.

[0006] (3) Hydraulic pilot control is also a dual-handle control, and is usually in ISO mode. Its characteristics are small operating force, sensitive action, and cost between mechanical control and electric control. However, the control mode is single and cannot be switched independently. Summary of the Invention

[0007] The purpose of this invention is to overcome the shortcomings of the prior art and provide a hydraulic system for a skid steer loader, its control method, and a skid steer loader. This system retains the characteristics of sensitive and convenient hydraulic pilot control, while also providing two operating modes, ISO and H, which users can freely switch according to actual needs. This enhances the adaptability of the machine to different working conditions, improves work efficiency, and has cost advantages.

[0008] This invention provides the following technical solution:

[0009] In one aspect, a hydraulic system for a skid steer loader is provided, comprising a travel pump, a first travel motor, a second travel motor, a working pump, a multi-way valve, a left hydraulic pilot handle, a right hydraulic pilot handle, a left handle oil circuit switching valve, and a right handle oil circuit switching valve.

[0010] The oil outlet of the working pump is connected to the oil inlet of the multi-way valve, and the oil outlet of the multi-way valve is respectively connected to the first tool cylinder and the second tool cylinder.

[0011] The oil outlet of the travel pump is connected to the oil inlet of the first travel motor and the second travel motor, and the control oil outlet of the travel pump is connected to the oil inlet of the left hydraulic pilot handle and the right hydraulic pilot handle through the first electromagnetic reversing valve.

[0012] The four control oil circuits of the left hydraulic pilot handle (front, back, left, right) are connected to the control oil inlet of the travel pump and the first tool control oil port of the multi-way valve through the oil circuit switching valve of the left handle.

[0013] The left and right control oil circuits of the right hydraulic pilot handle are connected to the second tool control oil port of the multi-way valve. The front and rear control oil circuits of the right hydraulic pilot handle are connected to the control oil inlet of the travel pump and the first tool control oil port of the multi-way valve through the right handle oil circuit switching valve.

[0014] Furthermore, it also includes a second electromagnetic reversing valve, through which the control oil outlet of the travel pump is connected to the brake oil ports of the first travel motor and the second travel motor respectively.

[0015] Furthermore, it also includes a hydraulic oil tank, with the suction ports of the travel pump and the working pump connected to the hydraulic oil tank, and the return ports of the first solenoid directional valve, the second solenoid directional valve, the left hydraulic pilot handle, the right hydraulic pilot handle and the multi-way valve connected to the hydraulic oil tank, and the drain ports of the travel pump, the first travel motor and the second travel motor connected to the hydraulic oil tank.

[0016] Furthermore, the traveling pump is equipped with a filter, which is installed on the oil line connected to the oil inlet of the traveling pump.

[0017] Furthermore, the left handle oil circuit switching valve includes a third solenoid directional valve and four first check valves and four shuttle valves connected to the third solenoid directional valve.

[0018] Furthermore, the right-hand handle oil circuit switching valve includes a fourth solenoid directional valve and four first check valves connected to the fourth solenoid directional valve.

[0019] In a second aspect, a control method for the hydraulic system of a skid steer loader as described in any one of the first aspects is provided, comprising:

[0020] When the left and right hydraulic circuit switching valves are not energized, the left hydraulic pilot handle can be moved forward, backward, left, and right to control the travel pump to drive the first and second travel motors. The right hydraulic pilot handle can be moved forward and backward to control the multi-way valve to drive the first tool cylinder to retract and extend. The right hydraulic pilot handle can be moved left and right to control the multi-way valve to drive the second tool cylinder to retract and extend, thus achieving ISO control mode.

[0021] When the left and right hydraulic circuit switching valves are energized, manipulating the left hydraulic pilot handle's forward and backward two paths can control the travel pump to drive the first travel motor, and manipulating the right hydraulic pilot handle's forward and backward two paths can control the travel pump to drive the second travel motor. Manipulating the left and right two paths of the left hydraulic pilot handle can control the multi-way valve to drive the first tool cylinder to retract and extend, and manipulating the right hydraulic pilot handle's left and right two paths can control the multi-way valve to drive the second tool cylinder to retract and extend, thus achieving the H control mode.

[0022] Furthermore, the specific method for implementing the ISO control mode includes: when the left and right handle oil circuit switching valves are not energized, the four control oil channels of the left hydraulic pilot handle (front, back, left, and right) are connected to the four control oil inlets of the travel pump through the left handle oil circuit switching valve. By manipulating the left hydraulic pilot handle to move forward, backward, left, and right, the travel pump oil output is controlled, driving the first and second travel motors to achieve the functions of forward, backward, left turn, and right turn of the entire machine. Simultaneously, the two control oil channels of the right hydraulic pilot handle (front and back) are connected to the first tool control oil port of the multi-way valve through the right handle oil circuit switching valve. By manipulating the right hydraulic pilot handle to move forward, backward, and left, the first tool control oil output of the multi-way valve is controlled, driving the first tool cylinder to retract and extend, achieving the function of the first tool. The two control oil channels of the right hydraulic pilot handle (left and right) are connected to the second tool control oil port of the multi-way valve. By manipulating the right hydraulic pilot handle to move left and right, the second tool control oil output of the multi-way valve is controlled, driving the second tool cylinder to retract and extend, achieving the function of the second tool.

[0023] Furthermore, the specific method for implementing the H control mode includes: when the left and right hydraulic control switch valves are energized, the two control oil paths of the left hydraulic pilot handle are connected to the two control oil inlets of the travel pump through the left hydraulic control switch valve, controlling the first travel motor to operate; the two control oil paths of the right hydraulic control pilot handle are connected to the two control oil inlets of the travel pump through the right hydraulic control switch valve, controlling the second travel motor to operate. By combining the actions of the left and right hydraulic control pilot handles, the machine's forward, backward, left turn, and right turn functions are achieved. The left hydraulic pilot handle has two control oil channels, one for left and one for right, connected to the first tool control oil port of the multi-way valve via the left handle oil circuit switching valve. By manipulating the left and right movements of the left hydraulic pilot handle, the output of the first tool control oil of the multi-way valve is controlled, driving the first tool cylinder to extend and retract, thus realizing the function of the first tool. The right hydraulic pilot handle has two control oil channels, one for left and one for right, connected to the second tool control oil port of the multi-way valve. By manipulating the right hydraulic pilot handle, the output of the second tool control oil of the multi-way valve is controlled, driving the second tool cylinder to retract and extend, thus realizing the function of the second tool.

[0024] Furthermore, the control timing of the left and right handle oil circuit switching valves is consistent, meaning they are either energized or de-energized simultaneously.

[0025] Thirdly, a skid steer loader is provided, comprising the skid steer loader hydraulic system of any one of the first aspects or a control method for executing the skid steer loader hydraulic system of any one of the second aspects.

[0026] Compared with the prior art, the beneficial effects of the present invention are:

[0027] (1) In this invention, the working pump supplies oil to the multi-way valve, and the traveling pump supplies control oil to the left and right hydraulic pilot handles through the first electromagnetic reversing valve. When the electromagnet of the first electromagnetic reversing valve is energized, the actions of the left and right hydraulic pilot handles are activated. By controlling whether the left and right handle oil circuit switching valves are energized, the control handles of the multi-way valve can be switched. When the left and right handle oil circuit switching valves are not energized, the function of the multi-way valve driving the first tool cylinder is controlled by the right hydraulic pilot handle. When the left and right handle oil circuit switching valves are energized, the function of the multi-way valve driving the first tool cylinder is controlled by the left hydraulic pilot handle. At the same time, the control of the traveling pump can be switched to control by the left hydraulic pilot handle alone, or by the combined control of the left and right hydraulic pilot handles. That is, the whole machine operation mode can be autonomously switched between ISO mode and H mode.

[0028] (2) Compared with the skid steer loader with conventional ISO mode hydraulic pilot control system, the skid steer loader hydraulic system with switchable control mode proposed in this invention enriches the operation mode of hydraulic skid steer products. Moreover, when dealing with working conditions that require high straightness of the whole machine, such as sweeping, ditching, and plowing, the two-hand control mode of the whole machine in H mode is more conducive to adjusting the working posture and improving the overall working efficiency.

[0029] (3) Compared with the skid steer loader with a conventional H-mode mechanical control system, the skid steer loader hydraulic system with switchable control mode proposed in this invention can greatly reduce the operator's workload. In ISO mode, the single handle control of the first implement and the first implement's operation mode is more conducive to the flexible movement of implements such as combined buckets and garden grabs.

[0030] (4) Compared with skid steer loaders with electronic control operation mode, the skid steer loader hydraulic system with switchable operation mode proposed in this invention realizes the autonomous switching between ISO and H operation modes in a low-cost manner without changing the travel pump and multi-way valve control method, which has significant cost advantages.

[0031] (5) The skid steer loader hydraulic system provided by the present invention has a reasonable structure, does not change the travel pump and multi-way valve control mode, has cost advantages, retains the characteristics of sensitive and convenient hydraulic pilot control, and has two operating modes, ISO and H, which users can switch freely according to actual needs, enhancing the adaptability of the whole machine to working conditions and improving work efficiency. Attached Figure Description

[0032] Figure 1 This is a schematic diagram of the hydraulic system of the skid steer loader in an embodiment of the present invention;

[0033] Figure 2 yes Figure 1 A schematic diagram of the travel pump, the first travel motor, and the second travel motor.

[0034] Figure 3 yes Figure 1 A schematic diagram of the first and second electromagnetic directional valves.

[0035] Figure 4 yes Figure 1 A schematic diagram of the left hydraulic pilot handle, the right hydraulic pilot handle, the left handle oil circuit switching valve, and the right handle oil circuit switching valve.

[0036] Figure 5 yes Figure 1 Schematic diagram of the oil circuit switching valve on the left-hand lever;

[0037] Figure 6 yes Figure 1 A schematic diagram of the multi-way valve, the first tool cylinder, and the second tool cylinder.

[0038] Figure 7 This is a schematic diagram of the operation of the left and right hydraulic pilot handles in ISO control mode in an embodiment of the present invention;

[0039] Figure 8 This is a schematic diagram of the operation of the left and right hydraulic pilot handles in the H control mode of this invention embodiment;

[0040] The following are labeled in the diagram: 1. Travel pump; 2. First travel motor; 3. Second travel motor; 4. Working pump; 5. Hydraulic oil tank; 6. Multi-way valve; 7. Left hydraulic pilot handle; 8. Right hydraulic pilot handle; 9. Left handle oil circuit switching valve; 9-1. First shuttle valve; 9-2. Second shuttle valve; 9-3. Third shuttle valve; 9-4. Fourth shuttle valve; 9-S. Third electromagnet; 10. Right handle oil circuit switching valve; 10-S. Fourth electromagnet; 11. Filter; 12. Second tool cylinder; 13. First tool cylinder; 14. Second solenoid directional valve; 14-S. Second electromagnet; 15. First solenoid directional valve; 15-S. First electromagnet. Detailed Implementation

[0041] The present invention will be further described below with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and should not be used to limit the scope of protection of the present invention.

[0042] Example 1

[0043] like Figure 1 As shown, this embodiment provides a skid steer loader hydraulic system, including a travel pump 1, a first travel motor 2, a second travel motor 3, a working pump 4, a hydraulic oil tank 5, a first solenoid directional valve 15, a second solenoid directional valve 14, a multi-way valve 6, a left hydraulic pilot handle 7, a right hydraulic pilot handle 8, a left handle oil circuit switching valve 9, a right handle oil circuit switching valve 10, a first implement cylinder 13, and a second implement cylinder 12.

[0044] like Figure 1 and Figure 2 As shown, the oil inlet S4 of the working pump 4 is connected to the hydraulic oil tank 5, and the oil outlet P4 of the working pump 4 is connected to the oil inlet P6 of the multi-way valve 6. The oil outlet of the multi-way valve 6 is connected to the first tool cylinder 13 and the second tool cylinder 12 respectively.

[0045] like Figure 1 and Figure 2 As shown, the oil suction port S1 of the travel pump 1 is connected to the hydraulic oil tank 5. The travel pump 1 is equipped with a filter 11, which is installed on the oil line connected to the oil suction port S1 of the travel pump 1 to filter impurities in the oil.

[0046] like Figure 1 and Figure 2 As shown, the oil outlet of the travel pump 1 is connected to the oil inlet of the first travel motor 2 and the second travel motor 3. Specifically, oil port A of the travel pump 1 is connected to oil port B3 of the second travel motor 3, oil port B of the travel pump 1 is connected to oil port A3 of the second travel motor 3, oil port C of the travel pump 1 is connected to oil port B2 of the first travel motor 2, and oil port D of the travel pump 1 is connected to oil port A2 of the first travel motor 2.

[0047] like Figures 1-3 As shown, the control oil outlet G1 of the travel pump 1 is connected to the oil inlet P7 of the left hydraulic pilot handle 7 and the oil inlet P8 of the right hydraulic pilot handle 8 through the first solenoid directional valve 15; wherein, the first solenoid directional valve 15 is provided with a first electromagnet 15-S.

[0048] like Figures 1-3 As shown, the control oil outlet G1 of the travel pump 1 is connected to the brake oil port Z2 of the first travel motor 2 and the brake oil port Z3 of the second travel motor 3 through the second electromagnetic reversing valve 14; wherein, the second electromagnetic reversing valve 14 is provided with a second electromagnet 14-S.

[0049] like Figure 1 and Figures 4-6 As shown, the four control oil circuits (front, rear, left, and right) of the left hydraulic pilot handle 7 are connected to the control oil inlet of the travel pump 1 and the first tool control oil port of the multi-way valve 6 via the left handle oil circuit switching valve 9. Specifically, the left handle oil circuit switching valve 9 includes a third solenoid directional valve and four first check valves and four shuttle valves connected to the third solenoid directional valve. The third solenoid directional valve is equipped with a third solenoid 9-S, and the four shuttle valves are the first shuttle valve 9-1, the second shuttle valve 9-2, the third shuttle valve 9-3, and the fourth shuttle valve 9-4. The four shuttle valves are respectively connected to the control oil inlets X1, X2, X3, and X4 of the travel pump. Two of the first check valves are connected to the control oil inlets X3 and X4 of the travel pump, and the other two first check valves are connected to the first tool control oil ports a1 and b1 of the multi-way valve 6.

[0050] like Figure 1 , Figure 4 and Figure 6 As shown, the left and right control oil circuits of the right hydraulic pilot handle 8 are connected to the second tool control oil ports a2 and b2 of the multi-way valve 6. The front and rear control oil circuits of the right hydraulic pilot handle 8 are connected to the control oil inlet of the travel pump 1 and the first tool control oil port of the multi-way valve 6 through the right handle oil circuit switching valve 10. Specifically, the right handle oil circuit switching valve 10 includes a fourth solenoid directional valve and four second check valves connected to the fourth solenoid directional valve. The fourth solenoid directional valve is equipped with a fourth solenoid 10-S. Two of the second check valves are connected to the control oil inlets X1 and X2 of the travel pump 1, and the other two second check valves are connected to the first tool control oil ports a1 and b1 of the multi-way valve 6.

[0051] like Figures 1-4 and Figure 6 As shown, the return ports T14, T15, T7, T8, and T6 of the first solenoid directional valve 15, the second solenoid directional valve 14, the left hydraulic pilot handle 7, the right hydraulic pilot handle 8, and the multi-way valve 6 are connected to the hydraulic oil tank 5. The drain ports L1, L2, and L3 of the travel pump 1, the first travel motor 2, and the second travel motor 3 are connected to the hydraulic oil tank 5.

[0052] The control logic of the skid steer loader hydraulic system provided in this embodiment is as follows:

[0053] When the vehicle is started, the working pump 4 supplies oil to the multi-way valve 6, and the travel pump 1 supplies control oil to the left hydraulic pilot handle 7 and the right hydraulic pilot handle 8 through the first solenoid directional valve 15. When the first solenoid 15-S of the first solenoid directional valve 15 is energized, the action of the left hydraulic pilot handle 7 and the right hydraulic pilot handle 8 is activated, and the control timing of the third solenoid 9-S of the left handle oil circuit switching valve 9 and the fourth solenoid 10-S of the right handle oil circuit switching valve 10 is consistent, that is, they are energized or de-energized at the same time.

[0054] By controlling the energization of the third electromagnet 9-S and the fourth electromagnet 10-S, the control handle of the multi-way valve 6 can be switched. When the third electromagnet 9-S and the fourth electromagnet 10-S are not energized, the function of the multi-way valve 6 driving the first tool cylinder 13 is controlled by the right hydraulic pilot handle 8. When the third electromagnet 9-S and the fourth electromagnet 10-S are energized, the function of the multi-way valve 6 driving the first tool cylinder 13 is controlled by the left hydraulic pilot handle 7. At the same time, the control of the travel pump 1 can be switched to be controlled by the left hydraulic pilot handle 7 alone, or by a combination of the left hydraulic pilot handle 7 and the right hydraulic pilot handle 8, that is, the overall machine operation mode can be automatically switched between ISO mode and H mode.

[0055] Example 2

[0056] like Figures 1-6 As shown, this embodiment provides a control method for the hydraulic system of the skid steer loader described in Embodiment 1. The first implement cylinder 13 is a boom cylinder, and the second implement cylinder 12 is a bucket cylinder. The specific control method is as follows:

[0057] When the third electromagnet 9-S of the left handle oil circuit switching valve 9 and the fourth electromagnet 10-S of the right handle oil circuit switching valve 10 are not energized, the left handle oil circuit switching valve 9 operates in the right position under the action of spring force. The four control oils of the left hydraulic pilot handle 7 (forward, backward, left, and right) are connected to the four control oil inlets X1, X2, X3, and X4 of the travel pump 1 through the four shuttle valves 9-1, 9-2, 9-3, and 9-4 in the left handle oil circuit switching valve 9. By operating the left hydraulic pilot handle 7 to move forward, backward, left, and right, the oil output of the travel pump 1 is controlled, driving the first travel motor 2 and the second travel motor 3 to realize the functions of forward, backward, left turn, and right turn of the whole machine. Simultaneously, the right-hand hydraulic circuit switching valve 10 operates in the right position under the action of spring force. The front and rear control oil of the right hydraulic pilot handle 8 is connected to the first implement control oil ports a1 and b1 of the multi-way valve 6 through the right-hand hydraulic circuit switching valve 10. By moving the right hydraulic pilot handle 8 forward and backward, the output of the first implement control oil of the multi-way valve 6 is controlled, driving the first implement cylinder 13 to retract and extend, realizing the function of the first implement, namely, realizing the function of lowering and raising the entire boom. The left and right control oil of the right hydraulic pilot handle 8 is connected to the second implement control oil ports a2 and b2 of the multi-way valve 6. By manipulating the right hydraulic pilot handle 8 left and right, the output of the second implement control oil of the multi-way valve 6 is controlled, driving the second implement cylinder 12 to retract and extend, realizing the function of the second implement, namely, realizing the function of retracting and tilting the entire bucket. At this time, the left hydraulic pilot handle 7 and the right hydraulic pilot handle 8 are in ISO control mode, such as... Figure 7 As shown in Table 1.

[0058] Table 1 ISO Control Modes

[0059]

[0060] When the third electromagnet 9-S controlling the left handle oil circuit switching valve 9 and the fourth electromagnet 10-S controlling the right handle oil circuit switching valve 10 are energized, the left handle oil circuit switching valve 9 operates in the left position under the thrust of the third electromagnet 9-S. The front and rear control oil of the left hydraulic pilot handle 7 is connected to the two control oil inlets X3 and X4 of the travel pump 1 through the left handle oil circuit switching valve 9, controlling the rotation of the first travel motor 2. At the same time, the right handle oil circuit switching valve 10 operates in the left position under the thrust of the fourth electromagnet 10-S. The front and rear control oil of the right hydraulic pilot handle 8 is connected to the two control oil inlets X1 and X2 of the travel pump 1 through the right handle oil circuit switching valve 10, controlling the rotation of the second travel motor 3. By combining the actions of the left hydraulic pilot handle 7 and the right hydraulic pilot handle 8, the functions of forward, backward, left turn and right turn of the whole machine are realized. Additionally, the left and right control oil channels of the left hydraulic pilot handle 7 are connected to the first implement control oil ports a1 and b1 of the multi-way valve 6 via the left handle oil circuit switching valve 9. By manipulating the left and right movements of the left hydraulic pilot handle 7, the output of the first implement control oil of the multi-way valve 6 is controlled, driving the first implement cylinder 13 to extend and retract, thus realizing the function of the first implement, namely, the lifting and lowering of the entire boom. The left and right control oil channels of the right hydraulic pilot handle 8 are connected to the second implement control oil ports a2 and b2 of the multi-way valve 6. By manipulating the right hydraulic pilot handle 8, the output of the second implement control oil of the multi-way valve 6 is controlled, driving the second implement cylinder 12 to retract and extend, thus realizing the function of the second implement, namely, the retraction and tilting of the entire bucket. At this time, the left and right hydraulic pilot handles 7 and 8 are in H control mode, such as... Figure 8 As shown in Table 2.

[0061] Table 2 H Control Mode

[0062]

[0063] Example 3

[0064] This embodiment provides a skid steer loader equipped with the skid steer loader hydraulic system described in Embodiment 1 or a control method that executes the skid steer loader hydraulic system described in Embodiment 2.

[0065] Those skilled in the art will understand that embodiments of this application can be provided as methods, systems, or computer program products. Therefore, this application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this application can take the form of a computer program product embodied on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0066] This application is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of this application. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart... Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0067] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0068] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0069] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A hydraulic system for a skid steer loader, characterized in that, Includes a travel pump (1), a first travel motor (2), a second travel motor (3), a working pump (4), a multi-way valve (6), a left hydraulic pilot handle (7), a right hydraulic pilot handle (8), a left handle oil circuit switching valve (9), and a right handle oil circuit switching valve (10); The oil outlet of the working pump (4) is connected to the oil inlet of the multi-way valve (6), and the oil outlet of the multi-way valve (6) is connected to the first tool cylinder (13) and the second tool cylinder (12) respectively. The oil outlet of the walking pump (1) is connected to the oil inlet of the first walking motor (2) and the second walking motor (3). The control oil outlet of the walking pump (1) is connected to the oil inlet of the left hydraulic pilot handle (7) and the right hydraulic pilot handle (8) through the first electromagnetic reversing valve (15). The four control oil circuits of the left hydraulic pilot handle (7) are connected to the control oil inlet of the walking pump (1) and the first tool control oil port of the multi-way valve (6) through the left handle oil circuit switching valve (9). The left and right two control oil circuits of the right hydraulic pilot handle (8) are connected to the second tool control oil port of the multi-way valve (6). The front and rear two control oil circuits of the right hydraulic pilot handle (8) are connected to the control oil inlet of the travel pump (1) and the first tool control oil port of the multi-way valve (6) through the right handle oil circuit switching valve (10).

2. The skid steer loader hydraulic system according to claim 1, characterized in that, It also includes a second electromagnetic reversing valve (14), through which the control oil outlet of the travel pump (1) is connected to the brake oil ports of the first travel motor (2) and the second travel motor (3) respectively.

3. The skid steer loader hydraulic system according to claim 1, characterized in that, It also includes a hydraulic oil tank (5), the suction ports of the travel pump (1) and the working pump (4) are connected to the hydraulic oil tank (5), the return ports of the first solenoid directional valve (15), the second solenoid directional valve (14), the left hydraulic pilot handle (7), the right hydraulic pilot handle (8) and the multi-way valve (6) are connected to the hydraulic oil tank (5), and the drain ports of the travel pump (1), the first travel motor (2) and the second travel motor (3) are connected to the hydraulic oil tank (5).

4. The skid steer loader hydraulic system according to claim 1, characterized in that, The walking pump (1) is equipped with a filter (11), which is installed on the oil line connected to the oil suction port of the walking pump (1).

5. The skid steer loader hydraulic system according to claim 1, characterized in that, The left handle oil circuit switching valve (9) includes a third solenoid directional valve and four first check valves and four shuttle valves connected to the third solenoid directional valve.

6. The skid steer loader hydraulic system according to claim 1, characterized in that, The right handle oil circuit switching valve (10) includes a fourth solenoid directional valve and four first check valves connected to the fourth solenoid directional valve.

7. A control method for the hydraulic system of a skid steer loader according to any one of claims 1 to 6, characterized in that, include: When the left handle oil circuit switching valve (9) and the right handle oil circuit switching valve (10) are not energized, the left hydraulic pilot handle (7) can be operated to move forward, backward and left and right to control the travel pump (1) to drive the first travel motor (2) and the second travel motor (3) to work. The right hydraulic pilot handle (8) can be operated to move forward and backward to control the multi-way valve (6) to drive the first tool cylinder (13) to retract and extend. The right hydraulic pilot handle (8) can be operated to move left and right to control the multi-way valve (6) to drive the second tool cylinder (12) to retract and extend, thus realizing the ISO control mode. When the left and right hydraulic circuit switching valves (9 and 10) are energized, the left hydraulic pilot handle (7) can be operated in two directions to drive the first travel motor (2) by driving the travel pump (1). The right hydraulic pilot handle (8) can be operated in two directions to drive the second travel motor (3). The left and right hydraulic pilot handle (7) can be operated in two directions to drive the first tool cylinder (13) by driving the multi-way valve (6) to retract and extend. The right hydraulic pilot handle (8) can be operated in two directions to drive the second tool cylinder (12) to retract and extend, thus realizing the H control mode.

8. The control method for the hydraulic system of a skid steer loader according to claim 7, characterized in that, The specific method for implementing the ISO control mode includes: when the left handle oil circuit switching valve (9) and the right handle oil circuit switching valve (10) are not energized, the four control oil lines of the left hydraulic pilot handle (7) are connected to the four control oil inlets of the travel pump (1) through the left handle oil circuit switching valve (9). By manipulating the left hydraulic pilot handle (7) to move forward, backward, left, and right, the travel pump (1) is controlled to output oil, driving the first travel motor (2) and the second travel motor (3), thereby realizing the functions of forward, backward, left turn, and right turn of the whole machine; at the same time, the two control oil lines of the right hydraulic pilot handle (8) are connected to the right handle oil circuit switching valve (9) through the left handle oil circuit switching valve (9). The handle oil circuit switching valve (10) is connected to the first tool control oil port of the multi-way valve (6). By moving the right hydraulic pilot handle (8) back and forth, the first tool control oil output of the multi-way valve (6) is controlled, driving the first tool cylinder (13) to retract and extend, thus realizing the function of the first tool. The left and right control oils of the right hydraulic pilot handle (8) are connected to the second tool control oil port of the multi-way valve (6). By manipulating the right hydraulic pilot handle (8) to move left and right, the second tool control oil output of the multi-way valve (6) is controlled, driving the second tool cylinder (12) to retract and extend, thus realizing the function of the second tool.

9. The control method for the hydraulic system of a skid steer loader according to claim 7, characterized in that, The specific method for implementing the H control mode includes: when the left handle oil circuit switching valve (9) and the right handle oil circuit switching valve (10) are energized, the front and rear control oil of the left hydraulic pilot handle (7) is connected to the two control oil inlets of the travel pump (1) through the left handle oil circuit switching valve (9), controlling the first travel motor (2) to move; the front and rear control oil of the right hydraulic pilot handle (8) is connected to the two control oil inlets of the travel pump (1) through the right handle oil circuit switching valve (10), controlling the second travel motor (3) to move. By combining the actions of the left hydraulic pilot handle (7) and the right hydraulic pilot handle (8), the functions of forward, backward, left turn and right turn of the whole machine are realized. The left and right control oils of the left hydraulic pilot handle (7) are connected to the first tool control oil port of the multi-way valve (6) through the left handle oil circuit switching valve (9). By manipulating the left hydraulic pilot handle (7) to move left and right, the output of the first tool control oil of the multi-way valve (6) is controlled, and the first tool cylinder (13) is driven to extend and retract, so as to realize the function of the first tool. The left and right control oils of the right hydraulic pilot handle (8) are connected to the second tool control oil port of the multi-way valve (6). By manipulating the right hydraulic pilot handle (8) to move left and right, the output of the second tool control oil of the multi-way valve (6) is controlled, and the second tool cylinder (12) is driven to retract and extend, so as to realize the function of the second tool.

10. A skid steer loader, characterized in that, Includes the skid steer loader hydraulic system according to any one of claims 1 to 6, or the control method for performing the skid steer loader hydraulic system according to any one of claims 7 to 9.

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