Hydrostatic walking system of loading machine and loading machine

Abstract

The invention discloses a loading machine static hydraulic walking system and a loading machine. The loading machine static hydraulic walking system comprises a walking pump assembly, an oil supplementing pump and a working pump which are coaxially driven. An outlet of the oil supplementing pump is connected with an inlet of the rotating speed sensing control valve, and a first outlet of the rotating speed sensing control valve is connected with an inlet of the reversing electromagnetic valve and a first inlet of the inching jogging control integrated valve. An inlet II of the inching jogging control integrated valve is connected with an outlet of the power-assisted control valve; a working port of the reversing electromagnetic valve is connected with a variable piston assembly for controlling the displacement of the walking pump assembly; the walking pump assembly is used for supplying oil to the walking motor; the working pump is used for supplying oil to the working device. The inching function and the inching crawling function are achieved in the hydraulic control pump and motor state, meanwhile, the speed separation control function of getting on and off is achieved, the requirements of the market for complex and changeable working conditions are met, and the system is more integrated and more compact.

Description

Technical Field

[0001] This invention belongs to the field of loader technology, specifically relating to a hydrostatic walking system for a loader and a loader. Background Technology

[0002] In existing technologies, some loaders use hydrostatic drives, and these loaders are characterized by varied operating conditions and are typically equipped with various implements. This necessitates more flexible and adaptable control of the entire machine. For example: 1. In some operating conditions, faster movement of the working device and slower travel speed are required, but existing loader hydraulic systems cannot achieve these functions, or achieving them would result in a complex and bulky hydraulic system, leading to a significant increase in manufacturing and maintenance costs. 2. For some small-tonnage, compact loaders, space constraints make it even more difficult to achieve these functions; therefore, how to integrate and design the hydrostatic system to fully utilize existing space has become an urgent problem to be solved. Summary of the Invention

[0003] To address the shortcomings of existing technologies, this invention provides a hydrostatic walking system and loader for a loader, which achieves inching and micro-creep functions under the control of a hydraulic pump and motor. At the same time, it enables speed separation for loading and unloading, adapting to the market's requirements for complex and variable working conditions. Furthermore, the system is more integrated and compact.

[0004] To achieve the above objectives, the technical solution adopted by the present invention is as follows: In a first aspect, a hydrostatic walking system for a loader is provided, comprising: a coaxially driven walking pump assembly, a replenishing pump, and a working pump; the outlet of the replenishing pump is connected to the inlet of a speed-sensing control valve, the outlet of the speed-sensing control valve is connected to the inlet of a reversing solenoid valve and the inlet of an inching micro-motion control integrated valve; the inlet of the inching micro-motion control integrated valve is connected to the outlet of a power assist control valve; the working port of the reversing solenoid valve is connected to a variable piston assembly for controlling the displacement of the walking pump assembly; the walking pump assembly is used to supply oil to the walking motor; the working pump is used to supply oil to the working device; the inching micro-motion control integrated valve includes: an inching pressure relief valve, the control end of which is connected to the inlet of the inching micro-motion control integrated valve, the inlet of which is connected to the inlet of the inching micro-motion control integrated valve, and the outlet of which is connected to an oil tank; an inching solenoid valve, the inlet of which is connected to the inlet of the inching micro-motion control integrated valve, the outlet of which is connected to an oil tank via an adjustable flow valve, and the control end of which is connected to a controller; the controller is connected to a high / low speed switching button.

[0005] Furthermore, the inlet of the travel pump assembly is connected to the outlet of the travel motor, and the outlet is connected to the inlet of the travel motor.

[0006] Furthermore, the working device includes a multi-way valve, with the outlet of the working pump connected to the inlet of the multi-way valve and the return port of the multi-way valve connected to the oil tank.

[0007] Furthermore, it also includes a suction oil filter, and the inlet of the replenishing pump and the return port of the multi-way valve are both connected to the oil tank through the suction oil filter.

[0008] Furthermore, when there is no action, the hydraulic oil output by the working pump flows back to the oil tank through the return port of the working device; the reversing solenoid valve must not be electrically in the neutral cut-off state, the hydraulic oil output by the replenishing pump cannot enter the variable piston assembly, the displacement of the travel pump assembly is zero, and there is no hydraulic oil output; the hydraulic oil output by the replenishing pump enters the replenishing overflow valve through the outlet of the speed sensing control valve, and overflows back to the oil tank through the replenishing overflow valve.

[0009] Furthermore, when the power assist control valve is activated, pressure is generated at the control end of the inching pressure relief valve. The inching pressure relief valve opens, and the hydraulic oil output by the replenishing pump flows into the oil tank through the speed sensing control valve and the inching pressure relief valve to relieve pressure. As a result, the hydraulic oil output by the replenishing pump enters the variable piston assembly through the speed sensing control valve and the reversing solenoid valve, reducing the oil pressure, decreasing the displacement of the travel pump assembly, and reducing the travel speed, thus realizing the inching function.

[0010] Furthermore, when in high speed, the inching solenoid valve is de-energized and in the cut-off position, so the micro-creep function is inactive. When in low speed, if the high / low speed switch button outputs a signal to the controller, the controller controls the inching solenoid valve to be energized and in the connected position. The hydraulic oil output by the replenishing pump flows into the oil tank through the speed sensing control valve, the inching solenoid valve, and the adjustable flow valve to form a pressure relief. As a result, the hydraulic oil output by the replenishing pump enters the variable piston assembly through the speed sensing control valve and the reversing solenoid valve, reducing the oil pressure, decreasing the displacement of the travel pump assembly, and reducing the travel speed, thus realizing the micro-creep function.

[0011] Furthermore, it also includes a differential lock control solenoid valve, the inlet of which is connected to the outlet of the speed sensing control valve, the working port of which is connected to the differential lock, and the control end of which is connected to the differential lock control button.

[0012] Furthermore, when the machine is started, the differential lock control solenoid valve is in a normally de-energized state, and the hydraulic oil circuit of the differential lock control solenoid valve is different, so the differential lock does not work; if the differential lock control button outputs a signal to the differential lock control solenoid valve, the control terminal of the differential lock control solenoid valve is energized, the differential lock control solenoid valve is in the connected position, and the hydraulic oil output by the replenishing pump flows into the differential lock through the speed sensing control valve and the differential lock control solenoid valve to realize the differential function.

[0013] In a second aspect, a loader is provided, the loader being equipped with the loader hydrostatic travel system described in the first aspect.

[0014] Compared with the prior art, the beneficial effects achieved by the present invention are as follows: (1) The present invention uses a coaxially driven walking pump assembly, a replenishing pump and a working pump; the outlet of the replenishing pump is connected to the inlet of the speed sensing control valve, the outlet of the speed sensing control valve is connected to the inlet of the reversing solenoid valve and the inlet of the inching micro-motion control integrated valve respectively; the inlet of the inching micro-motion control integrated valve is connected to the outlet of the power assist control valve; the working port of the reversing solenoid valve is connected to the variable piston assembly used to control the displacement of the walking pump assembly; the walking pump assembly is used to supply oil to the walking motor; the working pump is used to supply oil to the working device; the control end of the inching pressure relief valve is connected to the inlet of the inching micro-motion control integrated valve, the inlet is connected to the inlet of the inching micro-motion control integrated valve, and the outlet is connected to the oil tank; the inlet of the inching solenoid valve is connected to the inlet of the inching micro-motion control integrated valve, and the outlet is connected to the oil tank through an adjustable flow valve, and the control end is connected to the controller; the controller is connected to the high and low speed switching button; the present invention realizes the inching function and micro-motion crawling function in the state of hydraulic pump and motor, and at the same time realizes the speed separation control function of getting on and off the vehicle, adapting to the market requirements for complex and variable working conditions, and the system is more integrated and more compact; (2) This invention achieves the goal of changing the control pressure of the walking pump by using two methods: a manually controlled adjustable flow valve (micro-creep function) and a foot pedal controlled inch-advance micro-advance integrated valve (inch-advance control function). This separates the control of the machine's working device from the walking speed, making the control more flexible, more energy-efficient, and more adaptable to different working conditions. (3) The present invention adds inch advance control to the system, which reduces the use of the brakes for the deceleration of the whole machine and greatly extends the service life of the brake pads; (4) The present invention integrates the suction circuit pipelines of the working gear pump and the walking replenishment pump, and shares a suction return oil filter, making the entire hydrostatic system more compact and the cost lower. (5) The present invention achieves differential lock control by referencing the replenishment oil source without adding a new oil source, which makes the whole system have fewer components, occupies less space, and reduces costs. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the hydraulic principle of a loader hydrostatic walking system provided in an embodiment of the present invention; In the diagram: 1. Oil tank; 2. Travel pump assembly; 21. Speed ​​sensing control valve; 22. Replenishment overflow valve; 23. Replenishment pump; 24. Reversing solenoid valve; 25. Variable piston assembly; 3. Travel motor; 4. Inch-by-increase micro-motion control integrated valve; 41. Inch-by-increase pressure relief valve; 42. Inch-by-increase solenoid valve; 43. Adjustable flow valve; 5. Power steering control valve; 6. Working pump; 7. Multi-way valve; 8. Oil return filter; 9. Differential lock control solenoid valve; 10. High / low speed switching button; 11. Controller; 12. Differential lock control button. Detailed Implementation

[0016] 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.

[0017] Example 1 like Figure 1 As shown, a hydrostatic walking system for a loader includes: a coaxially driven walking pump assembly 2, a replenishing pump 23, and a working pump (gear pump) 6; the outlet (port C1) of the replenishing pump 23 is connected to the inlet (port D1) of a speed-sensing control valve 21, and the outlet one (port PS) of the speed-sensing control valve 21 is connected to the inlet (port M) of a reversing solenoid valve 24 and the inlet one (port Q1) of an inching micro-motion control integrated valve 4; the inlet two of the inching micro-motion control integrated valve 4 is connected to the outlet (port Z3) of a power assist control valve 5; the working port of the reversing solenoid valve 24 is connected to a variable piston assembly 25 for controlling the displacement of the walking pump assembly 2; the walking pump assembly 2 is used to supply oil to the walking motor 3; the working pump 6 is used to supply oil to the working device; the inching micro-motion control integrated valve 4 includes: an inching pressure relief valve 41, an inching solenoid valve 42 (two-position two-way solenoid valve), and an adjustable flow valve 43. The control end (oil port Z1) of the inch-in pressure relief valve 41 is connected to the inlet 2 of the inch-in micro-motion control integrated valve 4, the inlet (oil port Z4) is connected to the inlet 1 and outlet (oil port Z2) of the inch-in micro-motion control integrated valve 4, and is connected to the oil tank 1; the inlet of the inch-in solenoid valve 42 is connected to the inlet 1 and outlet (oil port E1) of the inch-in micro-motion control integrated valve 4, and is connected to the oil tank 1 through the adjustable flow valve 43 (the inlet of the adjustable flow valve 43 is oil port F1 and the outlet is oil port H1), and the control end is connected to the controller 11; the controller 11 is connected to the high and low speed switching button 10.

[0018] The inlet (oil port A1) of the walking pump assembly 2 is connected to the outlet (oil port A2) of the walking motor 3, and the outlet (oil port B1) is connected to the inlet (oil port B2) of the walking motor 3, forming a closed loop.

[0019] The working device includes a multi-way valve 7, the outlet (oil port C2) of the working pump 6 is connected to the inlet (oil port P1) of the multi-way valve 7, and the return port (oil port T1) of the multi-way valve 7 is connected to the oil tank 1.

[0020] The present invention also includes a suction oil filter 8, the inlet (oil port S) of the replenishing pump 23 is connected to the first inlet (oil port P3) of the suction oil filter 8; the return port of the multi-way valve 7 is connected to the second inlet (oil port R1) of the suction oil filter 8, and the outlet (oil port T3) of the suction oil filter 8 is connected to the oil tank 1.

[0021] The present invention also includes a differential lock control solenoid valve 9. The inlet (oil port P2) of the differential lock control solenoid valve 9 is connected to the outlet two (oil port G) of the speed sensing control valve 21, the working port (oil port A3) is connected to the differential lock, the control end is connected to the differential lock control button 12, and the return port T2 of the differential lock control solenoid valve 9 is connected to the oil tank 1.

[0022] In this invention, the high / low speed switching button 10 controls the energizing / disabling of the inching solenoid valve 42 via the controller 11. The differential lock control button 12 controls the energizing / disabling of the differential lock control solenoid valve 9.

[0023] After the engine is started, it has the following typical working states.

[0024] First working state: When the machine is started and there is no movement, the hydraulic oil output by the working pump 6 flows back to the oil tank 1 through the return port of the working device (multi-way valve 7); the reversing solenoid valve 24 is not energized and is in the neutral cut-off state, the hydraulic oil output by the replenishing pump 23 cannot enter the variable piston assembly 25, the displacement of the travel pump assembly 2 is zero, and there is no hydraulic oil output; the hydraulic oil output by the replenishing pump 23 enters the replenishing overflow valve 22 through the outlet of the speed sensing control valve 21, and overflows back to the oil tank 1 through the replenishing overflow valve 22.

[0025] During the operation of the whole machine, the hydraulic oil output by the replenishing pump 23 enters the replenishing overflow valve 22 through the outlet of the speed sensing control valve 21. The replenishing overflow valve 22 overflows and builds pressure to ensure that the control pressure of the walking system is maintained at a constant value, usually 2.5MPa, to ensure the replenishing pressure of the hydrostatic system. Excess oil overflows back to the oil tank 1 through the replenishing overflow valve 22.

[0026] At this time, the micro-motion control integrated valve 4 is in the off state; the hydraulic micro-motion function and the micro-motion crawling function are both inactive.

[0027] When the differential lock control solenoid valve 9 is de-energized, the working port of the differential lock control solenoid valve 9 is connected to the oil return port T2, and the differential function is not working.

[0028] Second operating mode (hydraulic control inching function): When the machine is started, by pressing the pedal of the power assist control valve 5, the control end of the inching pressure relief valve 41 generates pressure and opens the inching pressure relief valve 41. At this time, the inlet of the inching pressure relief valve 41 is connected to the inlet of the inching micro-motion control integrated valve 4, which releases the control pressure oil output from the outlet of the speed sensing control valve 21. The pressure of the variable piston assembly 25 is reduced by the control solenoid valve 24, the displacement of the travel pump assembly 2 is reduced, and the travel speed is reduced, thus achieving the control purpose of the inching function.

[0029] The third working state (micro-movement crawling function): When the machine is started, if the machine is in high speed, the inching solenoid valve 42 is de-energized, the oil circuit from the inching solenoid valve 42 to the adjustable flow valve 43 is blocked, and the micro-motion creep function does not work.

[0030] If the machine is in low speed, the high / low speed switch button 10 sends a signal to the controller 11. The controller 11 energizes the inching solenoid valve 42, connecting the oil circuit of the inching solenoid valve 42 to the adjustable flow valve 43. By manually adjusting the adjustable flow valve 43, the control oil output from the speed sensing control valve 21 in the travel pump assembly 2 will be depressurized and flow back to the oil tank 1 through the adjustable flow valve 43. At this time, the control pressure oil from the outlet of the speed sensing control valve 21 to the inlet of the reversing solenoid valve 24 decreases, the pressure of the control variable piston assembly 25 decreases, and the swashplate angle of the travel pump assembly 2 decreases, thereby reducing the overall machine speed and achieving the micro-motion crawling function.

[0031] In this invention, the main function of the speed-sensing control valve (DA speed-sensing control valve) 21 is that as the engine speed gradually increases, the flow rate output by the fuel pump 23 increases linearly, and the control pressure output by the speed-sensing control valve 21 to the reversing solenoid valve (ab reversing solenoid valve) 24 also increases linearly. Conversely, as the engine speed gradually decreases, the flow rate output by the fuel pump 23 decreases linearly, and the control pressure output by the speed-sensing control valve 21 to the reversing solenoid valve 24 also decreases linearly. The specific control principle of the speed-sensing control valve technology is prior art and will not be described in detail here.

[0032] This invention enables the control pressure output by the speed sensing control valve 21 to the reversing solenoid valve 24 to be linearly controlled by the engine speed, and can also be linearly changed to the control pressure output by the reversing solenoid valve 24 through manual control of the adjustable flow valve 43. However, the flow rate of the working pump 6 is always linearly controlled by the engine speed, thus achieving the purpose of separating the control of the working device speed and the travel speed.

[0033] In this invention, the inching solenoid valve 42 is energized only when the machine is in low-speed mode. The oil circuit between the inching solenoid valve 42 and the adjustable flow valve 43 is connected, allowing the adjustable flow valve 43 to release the control pressure of the variable piston assembly 25. In high-speed mode, the micro-creep function is inactive. This is a safety protection function because the speed ratio change rate is high in high-speed mode; if the adjustable flow valve 43 is accidentally rotated at this time, an accident may occur due to excessively rapid speed changes. Furthermore, the micro-creep function itself aims to reduce the walking speed while maintaining the working device speed, so its use in high-speed mode is meaningless.

[0034] In this invention, the most typical operating condition for the micro-motion crawling function is the sweeping operation. When the sweeper is mounted on the machine, the sweeper needs to rotate faster and walk slower; only by combining the two can the sweeping be more efficient. This invention fully achieves this.

[0035] The fourth operating state (differential function): When the machine is started, the differential lock control solenoid valve 9 is in a normally de-energized state, the oil circuit from the inlet to the working port of the differential lock control solenoid valve 9 is blocked, and the differential lock does not function.

[0036] When the differential lock function is required, the differential lock control button 12 controls the differential lock control solenoid valve 9 to be energized, and the oil replenishment pressure is introduced into the differential to realize the differential function.

[0037] Furthermore, when the entire machine is running, the outlet of the working pump 6 is connected to the inlet of the multi-way valve 7, the return port of the multi-way valve 7 is connected to the inlet of the suction oil filter 8, and the outlet of the suction oil filter 8 is connected to the oil tank 1, achieving the circulation of working hydraulic oil suction return oil. At the same time, the inlet of the replenishing pump 23 draws oil from the oil tank 1 through the suction oil filter 8, directly drawing the return oil from the multi-way valve 7 into the hydrostatic replenishing system, realizing the integrated design of the suction return pipeline of the working pump 6 and the replenishing pump 23, which saves more space.

[0038] This invention achieves inching and micro-creep functions in the state of hydraulic pump and motor, as well as speed separation function for loading and unloading. It also integrates a suction oil return scheme for the loading and unloading system. By referencing the replenishing oil source, differential lock control is achieved without adding a new oil source. This makes the hydraulic hydrostatic system more suitable for complex and variable working conditions in the market, and the system is more integrated and compact.

[0039] Example 2 Based on the loader hydrostatic walking system described in Embodiment 1, this embodiment provides a loader equipped with the loader hydrostatic walking system described in Embodiment 1.

[0040] 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 hydrostatic walking system for a loader, characterized in that, include: The coaxially driven travel pump assembly (2), the replenishing pump (23) and the working pump (6); The outlet of the replenishing pump (23) is connected to the inlet of the speed sensing control valve (21). The outlet of the speed sensing control valve (21) is connected to the inlet of the reversing solenoid valve (24) and the inlet of the micro-motion control integrated valve (4). The inlet of the micro-motion control integrated valve (4) is connected to the outlet of the power assist control valve (5). The working port of the reversing solenoid valve (24) is connected to the variable piston assembly (25) used to control the displacement of the travel pump assembly (2). The travel pump assembly (2) is used to supply oil to the travel motor (3); the working pump (6) is used to supply oil to the working device; The micro-motion control integrated valve (4) includes: The control end of the pressure relief valve (41) is connected to the inlet 2 of the pressure relief valve (4), the inlet is connected to the inlet 1 of the pressure relief valve (4), and the outlet is connected to the oil tank (1). The inlet of the inlet solenoid valve (42) is connected to the inlet of the inlet micro-motion control integrated valve (4), and the outlet is connected to the oil tank (1) through the adjustable flow valve (43). The control end is connected to the controller (11); the controller (11) is connected to the high and low speed switching button (10).

2. The loader hydrostatic travel system according to claim 1, characterized in that, The inlet of the walking pump assembly (2) is connected to the outlet of the walking motor (3), and the outlet is connected to the inlet of the walking motor (3).

3. The loader hydrostatic travel system according to claim 1, characterized in that, The working device includes a multi-way valve (7), the outlet of the working pump (6) is connected to the inlet of the multi-way valve (7), and the return port of the multi-way valve (7) is connected to the oil tank (1).

4. The loader hydrostatic travel system according to claim 3, characterized in that, It also includes a suction oil filter (8), and the inlet of the replenishing pump (23) and the return port of the multi-way valve (7) are connected to the oil tank through the suction oil filter (8).

5. The loader hydrostatic travel system according to claim 1, characterized in that, When there is no action, the hydraulic oil output by the working pump (6) flows back to the oil tank (1) through the return port of the working device; the reversing solenoid valve (24) must not be in the neutral cut-off state, the hydraulic oil output by the replenishing pump (23) cannot enter the variable piston assembly (25), the displacement of the travel pump assembly (2) is zero, and there is no hydraulic oil output; the hydraulic oil output by the replenishing pump (23) enters the replenishing overflow valve (22) through the outlet of the speed sensing control valve (21), and overflows back to the oil tank (1) through the replenishing overflow valve (22).

6. The loader hydrostatic travel system according to claim 1, characterized in that, When the power assist control valve (5) is activated, pressure is generated at the control end of the inching pressure relief valve (41). The inching pressure relief valve (41) opens, and the hydraulic oil output by the replenishing pump (23) flows into the oil tank (1) through the speed sensing control valve (21) and the inching pressure relief valve (41) to form pressure relief. As a result, the hydraulic oil output by the replenishing pump (23) enters the variable piston assembly (25) through the speed sensing control valve (21) and the reversing solenoid valve (24), and the oil pressure decreases. The displacement of the travel pump assembly (2) decreases, the travel speed decreases, and the inching function is realized.

7. The loader hydrostatic travel system according to claim 1, characterized in that, When in high speed, the inching solenoid valve (42) is de-energized and in the cut-off position, so the micro-motion crawling function does not work. When in low speed, if the high / low speed switching button (10) outputs a signal to the controller (11), the controller (11) controls the inch-advance solenoid valve (42) to be energized. The inch-advance solenoid valve (42) is in the connected position. The hydraulic oil output by the replenishing pump (23) flows into the oil tank (1) through the speed sensing control valve (21), the inch-advance solenoid valve (42), and the adjustable flow valve (43) to form a pressure relief. As a result, the hydraulic oil output by the replenishing pump (23) enters the variable piston assembly (25) through the speed sensing control valve (21) and the reversing solenoid valve (24), and the oil pressure decreases. The displacement of the travel pump assembly (2) decreases, the travel speed decreases, and the micro-motion crawling function is realized.

8. The loader hydrostatic travel system according to claim 1, characterized in that, It also includes a differential lock control solenoid valve (9), the inlet of which is connected to the outlet of the speed sensing control valve (21), the working port is connected to the differential lock, and the control end is connected to the differential lock control button (12).

9. The loader hydrostatic travel system according to claim 8, characterized in that, When the machine is started, the differential lock control solenoid valve (9) is in a normally de-energized state. The hydraulic oil circuit of the differential lock control solenoid valve (9) is different, and the differential lock does not work. If the differential lock control button (12) outputs a signal to the differential lock control solenoid valve (9), the control terminal of the differential lock control solenoid valve (9) is energized, the differential lock control solenoid valve (9) is in the connected position, and the hydraulic oil output by the replenishing pump (23) flows into the differential lock through the speed sensing control valve (21) and the differential lock control solenoid valve (9) to realize the differential function.

10. A loader, characterized in that, The loader is equipped with the loader hydrostatic travel system as described in any one of claims 1 to 9.

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