Tractor hydraulic system and tractor

Abstract

The present invention provides a tractor hydraulic system and a tractor, and relates to the technical field of agricultural machinery. The tractor hydraulic system provided by the present invention comprises: a working pump, a steering pump, a working system and a steering system; in a first working state, the working pump is connected to the working system and the steering system respectively, and the steering pump is connected to the steering system; in a second working state and a third working state, the working pump is connected to the working system, and the steering pump is connected to the working system and the steering system respectively. The tractor hydraulic system provided by the present invention solves the technical problems in the related art that the steering wheel is heavy when the tractor is idling and that certain working conditions cannot meet the lifting requirements.

Description

Technical Field

[0001] The present invention relates to the technical field of agricultural machinery, and in particular to a tractor hydraulic system and a tractor. Background Art

[0002] Tractors are essential mechanical equipment in agricultural production. They can be used for tilling land, sowing, fertilizing, transportation and other operations. They are mainly composed of a driving system, a working system, a steering system, a power shift system, etc. The tractor hydraulic system consists of two parts: the working system and the steering system.

[0003] like Figure 1 As shown, in the related technology, the tractor hydraulic system adopts a dual-pump independent hydraulic system, and the working system includes a lifting cylinder 1, a slow-descent valve 2, a relief valve 3, a distributor 4, a multi-way valve 5 and a working pump 8, etc. The multi-way valve 5 is connected in series with the distributor 4, and the oil output of the working pump 8 first passes through the multi-way valve 5 and then to the lifter. The oil output of the lifter is connected to the lifting cylinder 1, thereby realizing the lifting action.

[0004] The steering system includes components such as a steering oil cylinder 6, a steering gear 7, a steering pump 9, a steering oil pot 10, a booster control valve 11, a clutch booster 12 and a clutch oil cylinder 13. The hydraulic oil output by the steering pump of the steering system enters the steering gear 7. The steering pump 9 must meet the need for steering from low speed to high speed of the engine. Since the speeds are different at high speed and low speed, the flow of the steering pump 9 is also different. In order to avoid the driver from turning the steering wheel too fast (heavy steering) when the engine is at low speed, the displacement of the steering pump is generally determined according to the maximum speed of the steering wheel when the engine is idling. However, when the engine is running at high speed, the flow of the steering pump is large, and the steering speed is too fast at this time, which makes the car feel floating. In order to make the steering speed constant, a constant flow pump is used. This steering system is stable and reliable, but the overflow loss is large when the engine is at high speed. When applied to large-displacement steering, the volume is large and the overflow loss is greater. Therefore, the displacement of the steering pump cannot be too large.

[0005] The tractor hydraulic system in the related art has the following problems:

[0006] The steering is heavy at idle speed. When the tractor reaches the end of the field, the engine is usually running at idle speed. At this time, the volumetric efficiency and speed of the pump are relatively low, resulting in a low maximum steering wheel speed. This phenomenon is more obvious especially when the volumetric efficiency of the pump decreases as the use time increases.

[0007] The engine high-speed steering pump generates a lot of heat. The engine speed is usually high during field operations. At this time, the volumetric efficiency and speed of the pump are relatively high, resulting in overflow and heat of excess steering hydraulic oil, which causes the system oil temperature to rise, resulting in a decrease in oil viscosity, severe wear and tear of parts, a short lifespan, rapid oil deterioration, and frequent system failures.

[0008] The lifting speed is slow; because it is an independent system, the working pump cannot be too large due to factors such as torque limitation of the power take-off port, limited oil tank volume space, large system pressure loss and high heat generation. This results in slow lifting speed and the inability to meet the needs of certain working conditions.

[0009] Lifting and steering are independent systems. The steering system has an independent oil tank with a small size and small space for piping layout. It is impossible to add an oil return filter, which leads to poor cleanliness of the steering system and accelerated wear of components. Summary of the invention

[0010] A first aspect of the present invention provides a tractor hydraulic system to solve the technical problems in the related art that the steering wheel is heavy when the tractor is idling and certain working conditions cannot meet the lifting requirements.

[0011] The tractor hydraulic system provided by the present invention comprises: a working pump, a steering pump, a working system and a steering system;

[0012] In the first working state, the working pump is communicated with the working system and the steering system respectively, and the steering pump is communicated with the steering system;

[0013] In the second working state and the third working state, the working pump is communicated with the working system, and the steering pump is communicated with the working system and the steering system respectively.

[0014] Furthermore, the tractor hydraulic system also includes a combining and diverting control valve, which is connected to the working pump, the steering pump, the working system and the steering system respectively, and is used to control the connection and disconnection between the working pump, the steering pump, the working system and the steering system.

[0015] Furthermore, the displacement of the steering pump is B=0.7A, wherein A is the displacement of the steering pump in the same hydraulic system in the related art.

[0016] Furthermore, the tractor hydraulic system also includes an oil return filter and an oil return tank, and the return oil of the working system and the return oil of the steering system both pass through the oil return filter and enter the oil return tank.

[0017] Furthermore, the steering system includes a steering gear and a steering cylinder, and the steering gear is connected to the combining and diverting control valve and the steering cylinder respectively.

[0018] Furthermore, the steering gear is a load sensing steering gear.

[0019] Furthermore, the steering system also includes a booster control valve, a clutch booster and a clutch cylinder. The booster control valve is connected to the steering gear and the clutch booster respectively, and the clutch booster is connected to the clutch cylinder.

[0020] Furthermore, the working system includes a multi-way valve, a distributor, a slow-descent valve, an overflow valve and a lifting cylinder. The multi-way valve is connected to the combining and diverting control valve and the distributor respectively, the distributor is connected to the slow-descent valve and the overflow valve respectively, and the slow-descent valve is connected to the lifting cylinder.

[0021] Furthermore, the tractor hydraulic system also includes an oil inlet filter, which is arranged on the oil inlet lines of the working pump and the steering pump.

[0022] The second aspect of the present invention provides a tractor to solve the technical problems in the related art that when the tractor is idling, the steering wheel speed is low and certain working conditions cannot meet the lifting requirements.

[0023] The tractor provided by the present invention comprises the above-mentioned tractor hydraulic system.

[0024] The tractor hydraulic system and tractor provided by the present invention include: a working pump, a steering pump, a working system and a steering system; in the first working state, the working pump is connected to the working system and the steering system respectively, and the steering pump is connected to the steering system; in the second working state and the third working state, the working pump is connected to the working system, and the steering pump is connected to the working system and the steering system respectively. When the tractor reaches the end of the field, the engine is usually running at idle speed. At this time, the volumetric efficiency and rotation speed of the steering pump are both low, and the flow of the steering system is insufficient, so that the tractor hydraulic system is in the first working state, and part of the flow of the working pump is preferentially merged into the steering system, solving the problem of heavy idling steering; when the throttle is turned at medium and high speed, the tractor hydraulic system is in the second state, and the steering pump, in addition to the flow diverted to the steering gear, the excess flow of the steering pump is merged into the working system; when lifting at full speed, the tractor hydraulic system is in the third working state, because the excess flow of the steering pump is merged into the working pump, the flow of the working system is higher than that of the original system, so the maximum lifting speed is improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the related technologies, the drawings required for use in the specific embodiments or the related technical descriptions will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0026] Figure 1 It is a schematic diagram of a tractor hydraulic system in the related art;

[0027] Figure 2 A schematic diagram of a tractor hydraulic system provided by an embodiment of the present invention;

[0028] Figure 3 A schematic structural diagram of a flow combining and dividing control valve of a tractor hydraulic system provided by an embodiment of the present invention;

[0029] Figure 4 for Figure 3 A cross-sectional view;

[0030] Figure 5 for Figure 3 Cross-sectional view along the B axis;

[0031] Figure 6 A schematic diagram of a combined flow control valve in a first working state of a tractor hydraulic system provided by an embodiment of the present invention;

[0032] Figure 7 A schematic diagram of a combined flow control valve in a second working state of a tractor hydraulic system provided by an embodiment of the present invention;

[0033] Figure 8 A schematic diagram of a combined flow control valve in a third working state of a tractor hydraulic system provided by an embodiment of the present invention;

[0034] Fig. 9 A schematic diagram of a flow divider control valve when a clutch booster pedal is depressed in a tractor hydraulic system provided by an embodiment of the present invention.

[0035] Icons: 1-lifting cylinder; 2-slow-down valve; 3-overflow valve; 4-distributor; 5-multi-way valve; 6-steering cylinder; 7-steering gear; 8-working pump; 9-steering pump; 10-steering oil pot; 11-booster control valve; 12-clutch booster; 13-clutch cylinder; 14-combination and diversion control valve; 141-steering gear L interface; 142-steering gear interface; 143-multi-way valve interface; 144-oil return port; 145-steering pump interface; 146-working pump interface; 147-steering gear T interface; 15-return oil tank. DETAILED DESCRIPTION

[0036] The technical solution of the present invention will be described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described embodiments are only 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 ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0037] In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance.

[0038] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0039] Embodiment 1

[0040] The tractor hydraulic system provided by the embodiment of the present invention comprises: a working pump 8, a steering pump 9, a working system and a steering system; in a first working state, the working pump 8 is connected to the working system and the steering system respectively, and the steering pump 9 is connected to the steering system; in a second working state and a third working state, the working pump 8 is connected to the working system, and the steering pump 9 is connected to the working system and the steering system respectively.

[0041] Furthermore, the tractor hydraulic system also includes a combining and diverting control valve 14, which is connected to the working pump 8, the steering pump 9, the working system and the steering system respectively. The combining and diverting control valve 14 is used to control the connection and disconnection between the working pump 8, the steering pump 9, the working system and the steering system.

[0042] like Figures 3 to 5 As shown, the combining and diverting control valve 14 has a steering gear L interface 141, a steering gear interface 142, a multi-way valve interface 143, an oil return port 144, a steering pump interface 145, a working pump interface 146 and a steering gear T interface 147; the steering gear L interface 141 is connected to the L port of the steering gear 7, the steering gear interface 142 is connected to the P port of the steering gear 7, the multi-way valve interface 143 is connected to the oil inlet of the multi-way valve 5, the oil return port 144 is connected to the oil return tank 15, the steering pump interface 145 is connected to the steering pump 9, the working pump interface 146 is connected to the working pump 8, and the steering gear T interface 147 is connected to the T port of the steering gear 7.

[0043] When steering at idle speed, the steering flow is insufficient and the valve core is in a Figure 6 Position, the flow of steering pump 9 is fully supplied to steering gear 7, part of the flow of working pump 8 is combined to steering, and part is supplied to the working system. When the throttle is turned at medium and high speed, the valve core is in the position under the action of spring force and load sensing pressure. Figure 7 Position, the excess flow of the steering pump 9 merges into the working system through the oil channel inside the valve body. When the valve core is in the position under the action of the spring force and the load sensing pressure, the valve core is in the position under the action of the spring force and the load sensing pressure. Figure 8 Position, the steering pump 9 only has a very small amount of oil to supply the steering gear 7, and all the excess flow is combined into the working system through the oil channel inside the valve body.

[0044] Furthermore, the displacement of the steering pump 9 is B=0.7A, where A is the displacement of the steering pump in the same hydraulic system in the related art.

[0045] Compared with the related technology, the displacement of the steering pump 9 is reduced. When the engine is running at medium and high speed, the steering pump 9 has a high-pressure overflow except for the flow diverted to the steering gear 7. Since the displacement of the steering pump 9 is reduced, the overflow heat is reduced, the system temperature is lowered, and the wear of the steering system components is reduced.

[0046] Furthermore, the tractor hydraulic system further includes an oil return filter and an oil return tank 15 , and the oil return of the working system and the oil return of the steering system both pass through the oil return filter and enter the oil return tank 15 .

[0047] like Figure 2 As shown, the return oil circuit of the steering system is connected to the combined diverter control valve 14, and the combined diverter control valve 14 has a return oil port 144. The return oil port 144 of the combined diverter control valve 14 is connected to the return oil tank 15. The return oil filter is arranged on the return oil circuit of the working system. Along the flow direction of the return oil, the return oil filter is located downstream of the return oil port 144.

[0048] Compared with the related art, the tractor hydraulic system provided in the embodiment of the present invention eliminates the steering oil pot 10, and the return oil of the steering pump 9 and the return oil of the working pump 8 share the return oil filter, thereby improving the problems of high oil temperature and difficult cleanliness control of the original steering system.

[0049] Furthermore, the steering system includes a steering gear 7 and a steering cylinder 6, and the steering gear 7 is connected to the combining and splitting control valve 14 and the steering cylinder 6 respectively.

[0050] like Figure 2 As shown, the P port of the steering gear 7 is connected to the steering gear interface 142 of the combined diverter control valve 14, the T port of the steering gear 7 is connected to the steering gear T interface 147 of the combined diverter control valve 14, the L port of the steering gear 7 is connected to the steering gear L interface 141 of the combined classification control valve, the R port of the steering gear 7 is connected to the first chamber of the steering cylinder 6, and the L port of the steering gear 7 is connected to the second chamber of the steering cylinder 6.

[0051] The hydraulic oil flowing out of the steering gear interface 142 of the combined flow-dividing control valve 14 enters the steering gear 7 through the P port, and then enters the steering cylinder 6. The steering cylinder 6 drives the corresponding actuator to perform the steering operation.

[0052] Furthermore, the steering gear 7 is a load sensing steering gear 7 .

[0053] The load sensing steering gear controls the amount of hydraulic oil entering the steering gear 7 according to the load size, preventing excessive hydraulic oil from overflowing and reducing losses.

[0054] Furthermore, the steering system also includes a booster control valve 11 , a clutch booster 12 and a clutch cylinder 13 . The booster control valve 11 is connected to the steering gear 7 and the clutch booster 12 respectively, and the clutch booster 12 is connected to the clutch cylinder 13 .

[0055] like Figure 2 As shown, the booster control valve 11 is respectively connected to the T port of the steering gear 7, the clutch booster 12 and the oil return tank 15, and the clutch booster 12 is respectively connected to the clutch cylinder 13 and the oil return tank 15.

[0056] When the steering wheel is turned and the clutch pedal is pressed, pressure is generated at the T port of the steering gear 7, and the oil enters the T port 147 of the steering gear to push the valve stem downward, closing the flow control valve 14 in the closed position. Fig. 9 In the state shown, the merging channel from the steering pump 9 to the working oil circuit is closed, and the oil enters the clutch booster 12 to push the clutch cylinder 13 to work; when the steering wheel does not move and the clutch pedal is pressed, the flow of the steering pump 9 is controlled by the clutch pressure signal to enter the clutch booster 12 to meet the clutch assist demand.

[0057] Furthermore, the working system includes a multi-way valve 5, a distributor 4, a slow-descent valve 2, a relief valve 3 and a lifting cylinder 1. The multi-way valve 5 is respectively connected to the combining and diverting control valve 14 and the distributor 4, the distributor 4 is respectively connected to the slow-descent valve 2 and the relief valve 3, and the slow-descent valve 2 is connected to the lifting cylinder 1.

[0058] like Figure 2 As shown, the oil inlet of the multi-way valve 5 is connected to the multi-way valve interface 143 of the combining and diverting control valve 14, the distributor 4 is connected in series with the multi-way valve 5, the oil output of the working pump 8 first passes through the multi-way valve 5, and then to the lifter, and the oil output of the lifter is connected to the lifting cylinder 1, thereby realizing the lifting action.

[0059] Furthermore, the tractor hydraulic system also includes an oil inlet filter, which is arranged on the oil inlet lines of the working pump 8 and the steering pump 9.

[0060] like Figure 2As shown, the oil inlet filter is arranged on the oil inlet line of the working pump 8, and the oil inlet line of the steering pump 9 is connected with the oil inlet line of the working pump 8. The connection point is located downstream of the oil inlet filter. The filtered hydraulic oil enters the working pump 8 and the steering pump 9 to prevent impurities from entering the system and causing damage.

[0061] Embodiment 2

[0062] The second embodiment of the present invention provides a tractor to solve the technical problems in the related art that when the tractor is idling, the steering wheel speed is low and certain working conditions cannot meet the lifting requirements.

[0063] A tractor provided by an embodiment of the present invention includes the above-mentioned tractor hydraulic system.

[0064] The tractor hydraulic system and tractor provided by the embodiment of the present invention include: a working pump 8, a steering pump 9, a working system and a steering system; in the first working state, the working pump 8 is connected to the working system and the steering system respectively, and the steering pump 9 is connected to the steering system; in the second working state and the third working state, the working pump 8 is connected to the working system, and the steering pump 9 is connected to the working system and the steering system respectively. When the tractor reaches the end of the field, the engine is usually running at idle speed. At this time, the volumetric efficiency and speed of the steering pump 9 are both low, and the flow of the steering system is insufficient, so that the tractor hydraulic system is in the first working state, and part of the flow of the working pump 8 is preferentially merged into the steering system, solving the problem of heavy idling steering; when the throttle is turned at medium and high speed, the tractor hydraulic system is in the second state, and the steering pump 9, in addition to the flow diverted to the steering gear 7, the excess flow of the steering pump 9 is merged into the working system; when lifting at full speed, the tractor hydraulic system is in the third working state, because the excess flow of the steering pump 9 is merged into the working pump 8, the flow of the working system is higher than that of the original system, so the maximum lifting speed is improved.

[0065] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A tractor hydraulic system, characterized in that: include: Working pump, steering pump, working system and steering system; In the first working state, the working pump is communicated with the working system and the steering system respectively, and the steering pump is communicated with the steering system; In the second working state and the third working state, the working pump is connected to the working system, and the steering pump is connected to the working system and the steering system respectively; The tractor hydraulic system further comprises a flow combining and dividing control valve, wherein the flow combining and dividing control valve is respectively connected to the working pump, the steering pump, the working system and the steering system, and the flow combining and dividing control valve is used to control the connection and disconnection between the working pump, the steering pump, the working system and the steering system; The steering system comprises a steering gear and a steering cylinder, wherein the steering gear is communicated with the combining and splitting control valve and the steering cylinder respectively; The steering system further comprises a booster control valve, a clutch booster and a clutch oil cylinder, wherein the booster control valve is communicated with the steering gear and the clutch booster respectively, and the clutch booster is communicated with the clutch oil cylinder; The working system comprises a multi-way valve, a distributor, a slow-down valve, a relief valve and a lifting cylinder, wherein the multi-way valve is respectively connected to the flow combining and diverting control valve and the distributor, the distributor is respectively connected to the slow-down valve and the relief valve, and the slow-down valve is connected to the lifting cylinder; The displacement of the steering pump is B=0.7A, where A is the displacement of the steering pump in the same hydraulic system of the related art; The tractor hydraulic system further comprises an oil return filter and an oil return tank, and the return oil of the working system and the return oil of the steering system both pass through the oil return filter and enter the oil return tank; The tractor hydraulic system further comprises an oil inlet filter, which is arranged on the oil inlet lines of the working pump and the steering pump; The combining and diverting control valve has a steering gear L interface, a steering gear interface, a multi-way valve interface, an oil return port, a steering pump interface, a working pump interface and a steering gear T interface; the steering gear L interface is connected to the L port of the steering gear, the steering gear interface is connected to the P port of the steering gear, the multi-way valve interface is connected to the oil inlet of the multi-way valve, the oil return port is connected to the oil return tank, the steering pump interface is connected to the steering pump, the working pump interface is connected to the working pump, and the steering gear T interface is connected to the T port of the steering gear.

2. The tractor hydraulic system according to claim 1, characterized in that: The steering gear is a load sensing steering gear.

3. A tractor, characterized in that: A tractor hydraulic system comprising the tractor hydraulic system according to any one of claims 1 to 2.

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