Hydraulic system and tractor

Abstract

The invention belongs to the field of engineering machinery, and discloses a hydraulic system and a tractor, the hydraulic system comprises a hydraulic oil tank and a main valve, and an oil return port of the main valve is connected with a main valve oil return path; the hydraulic pump set comprises a booster pump and a main pump which are connected in series, and the main pump is arranged on the oil outlet side of the booster pump and used for supplying oil to an oil inlet of the main valve; the integrated filter comprises an oil suction filter and an oil return filter arranged in an oil return path of the main valve, and an oil filter oil inlet of the oil suction filter is connected to the hydraulic oil tank through an oil suction path; a booster pump oil suction oil way is connected between an oil filter oil outlet of the oil suction filter and an oil suction port of the booster pump, and an oil filter oil outlet of the oil return filter is hydraulically connected to the booster pump oil suction oil way. According to the tractor and the hydraulic system thereof, hydraulic return oil does not directly enter the hydraulic oil tank, and correspondingly, the situation that oil with poor cleanliness in the hydraulic oil tank enters an oil suction opening of the hydraulic pump is reduced as much as possible; oil suction of the main pump can be maintained in a certain positive pressure oil suction state, and the cleanliness of oil liquid is ensured.

Description

Technical Field

[0001] The present application belongs to the field of working machinery, and in particular, relates to a hydraulic system and a tractor. Background Art

[0002] In the tractor hydraulic system, the chassis housing of the transmission is generally used as a hydraulic oil container. However, the transmission chassis housing as a hydraulic oil tank has defects such as low oil suction point, poor general cleanliness, many oil suction bubbles, and high negative pressure of plunger pump suction oil, which often lead to poor stability of the hydraulic system, high failure rate, and high maintenance cost. In particular, this pump suction environment cannot meet the operating requirements under harsh working conditions such as low temperature and high speed operation. Summary of the invention

[0003] The purpose of the present application is to provide a hydraulic system and a tractor, which are conducive to pumping oil and can maintain a high level of cleanliness of the hydraulic system.

[0004] To achieve the above objectives, the present application provides a hydraulic system, the hydraulic system comprising:

[0005] A hydraulic oil tank and a main valve, wherein the oil return port of the main valve is connected to the main valve oil return circuit;

[0006] A hydraulic pump group, comprising a booster pump and a main pump arranged in series, wherein the main pump is arranged at the oil outlet side of the booster pump and is used to supply oil to the oil inlet of the main valve;

[0007] An integrated filter, comprising an oil suction filter and an oil return filter arranged in the oil return oil circuit of the main valve, wherein the oil filter inlet of the oil suction filter is connected to the hydraulic oil tank through the oil suction oil circuit;

[0008] Wherein, a boost pump suction oil circuit is connected between the oil filter outlet of the oil suction filter and the oil suction port of the boost pump, and the oil filter outlet of the return oil filter is hydraulically connected to the boost pump suction oil circuit.

[0009] In some embodiments, the integrated filter further comprises:

[0010] An oil suction filter bypass valve is connected in parallel with the oil suction filter and bypasses the oil suction oil circuit and the boost pump oil suction oil circuit.

[0011] In some embodiments, the integrated filter further comprises:

[0012] The return oil filter bypass valve bypasses the oil filter inlet connecting the oil suction circuit and the return oil filter.

[0013] In some embodiments, the hydraulic system comprises:

[0014] An oil suction bypass valve, which is a back pressure valve and is bypass-connected between the oil suction oil circuit of the booster pump and the oil suction port of the main pump;

[0015] The hydraulic oil can flow from the oil suction port of the main pump through the oil suction bypass valve to the oil suction oil path of the booster pump and be blocked in the reverse direction.

[0016] In some embodiments, the hydraulic oil tank is a chassis housing oil tank.

[0017] In some embodiments, the oil suction filter is a coarse filter, and the oil return filter is a fine filter.

[0018] In some embodiments, the hydraulic oil tank is a chassis housing oil tank.

[0019] In some embodiments, the set pumping flow rate of the boosting pump is greater than the set pumping flow rate of the main pump.

[0020] In some embodiments, the hydraulic system comprises:

[0021] The radiator is arranged in the main valve oil return path between the oil return filter and the oil return port of the main valve.

[0022] In addition, the present application also provides a tractor, which includes the hydraulic system described in the present application.

[0023] In the tractor and its hydraulic system of the present application, the return oil of each actuator passes through the return oil port of the main valve, the return oil circuit of the main valve, and the return oil filter in the integrated filter. After fine filtration, it enters the boost pump suction oil circuit and flows to the suction port of the boost pump. It can be pumped again and supply oil to each actuator, so that the hydraulic return oil does not directly enter the hydraulic oil tank, and correspondingly reduces the oil with poor cleanliness in the hydraulic oil tank to enter the hydraulic pump suction port as much as possible. The boost pump can also suck the hydraulic oil in the hydraulic oil tank through the oil suction filter pump to meet the flow demand of the main pump, and can also maintain the oil suction of the main pump at a certain positive pressure suction state. The integrated filter for suction return oil greatly reduces the use of oil in the oil tank, ensures the cleanliness of the oil, can maintain the cleanliness of the system at a relatively stable level, and the maintenance time of the filter element is long, and replacement is more convenient and quick.

[0024] Other advantages of the present application and the technical effects of the preferred embodiments will be further described in the following specific embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The accompanying drawings are used to provide an understanding of the present application and constitute a part of the specification. Together with the following specific embodiments, they are used to explain the present application but do not constitute a limitation to the present application. In the accompanying drawings:

[0026] Figure 1A hydraulic principle diagram of a hydraulic system according to an embodiment of the present application;

[0027] Figure 2 for Figure 1 Schematic diagram of the integrated filter in; and

[0028] Figure 3 The hydraulic principle diagram of a hydraulic system according to another embodiment of the present application.

[0029] Description of Reference Numerals

[0030] 1 Hydraulic oil tank 2 Integrated filter

[0031] 3 Suction bypass valve 4 Booster pump

[0032] 5 Radiator 6 Main valve

[0033] 7 Main pump H oil suction circuit

[0034] a. Suction filter b. Return filter

[0035] e Suction filter bypass valve f Return filter bypass valve

[0036] T Oil return port P Oil inlet port

[0037] T1 Main valve oil return line P1 Booster pump oil suction line DETAILED DESCRIPTION

[0038] The specific implementation of the present application is described in detail below in conjunction with the accompanying drawings. It should be understood that the specific implementation described herein is only used to illustrate and explain the present application and is not intended to limit the present application. It should be noted that, in the absence of conflict, the implementations in the present application and the features in the implementations can be combined with each other.

[0039] The hydraulic system and tractor of the present application will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0040] This application discloses a novel hydraulic system. Figure 1 As shown, the hydraulic system of this embodiment includes:

[0041] The hydraulic oil tank 1 and the main valve 6, the return oil port T of the main valve 6 is connected to the main valve return oil circuit T1;

[0042] A hydraulic pump group, comprising a booster pump 4 and a main pump 7 arranged in series, wherein the main pump 7 is arranged at the oil outlet side of the booster pump 4 and is used to supply oil to the oil inlet P of the main valve 6;

[0043] The integrated filter 2 includes an oil suction filter a and an oil return filter b arranged in the oil return oil circuit T1 of the main valve, and the oil filter inlet of the oil suction filter a is connected to the hydraulic oil tank 1 through the oil suction oil circuit H;

[0044] Among them, a booster pump suction oil circuit P1 is connected between the oil filter outlet of the oil suction filter a and the oil suction port of the booster pump 4, and the oil filter outlet of the return oil filter b is hydraulically connected to the booster pump suction oil circuit P1.

[0045] from Figure 1 It can be seen that the hydraulic return oil from the return port T of the main valve 6 passes through the main valve return oil circuit T1 and the return oil filter b of the integrated filter 2, enters the boost pump suction oil circuit P1 and flows to the suction port of the boost pump 4, so that the hydraulic return oil does not directly enter the hydraulic oil tank 1, and minimizes the oil with poor cleanliness in the hydraulic oil tank 1 from entering the hydraulic pump suction port.

[0046] Among them, the booster pump 4 of the hydraulic pump group can also suck the hydraulic oil in the hydraulic oil tank 1 through the oil suction filter a to meet the flow demand of the main pump 7. In this embodiment, the booster pump 4 can be a gear pump, and the main pump 7 can be a load-sensitive plunger pump. By adding the booster pump 4, the oil suction of the load-sensitive plunger pump can be maintained at a certain positive pressure oil suction state, and by Figure 2 The new integrated filter 2 shown can maintain the cleanliness of the system and achieve high speed, low cost and easy maintenance of the hydraulic system.

[0047] Comparatively, existing hydraulic systems generally do not have oil suction filters, and there is no oil suction cleanliness control technology, which cannot solve the problem of system oil suction cleanliness. If an oil suction filter is added, the system filtration layout will be relatively complex and the cost will be high. In addition, existing systems generally do not pay attention to the cleanliness of the return oil. For multiple hydraulic circuits with multiple actuators, there is also a lack of control over the oil suction cleanliness of the shared oil system, resulting in a high risk of oil contamination between circuits and a short maintenance life. Figure 1 The integrated oil return filter shown greatly reduces the use of oil in the oil tank and the closed-loop oil inlet and return filtration ensures the cleanliness of the oil. It can also reduce the oil pressure of the hydraulic oil tank 1. At the same time, the system cleanliness is maintained at a relatively stable level, the maintenance time of the filter element is long, and the replacement is more convenient and quick.

[0048] In the present embodiment, the hydraulic oil tank 1 is a chassis housing oil tank. It is well known to those skilled in the art that the chassis housing of the transmission of a tractor can generally be used as a hydraulic oil container, but this has many defects such as a low oil suction point, generally poor cleanliness, many oil suction bubbles, and a high negative pressure of the plunger pump. The hydraulic system has poor stability, a high failure rate, and high maintenance costs. Once under harsh working conditions such as low temperature and high speed operation, it is difficult for the main pump to pump hydraulic oil from the chassis housing oil tank at a flow rate that meets the operating requirements. In this case, the hydraulic system of the present application greatly reduces the use of oil with poor cleanliness in the chassis housing oil tank through the return oil filtration and closed-loop use of the main valve 6, thereby reducing the requirements for the use of the chassis housing oil tank as a hydraulic oil container.

[0049] See also Figure 1 , Figure 2 The integrated filter 2 may also include an oil suction filter bypass valve e, which is connected in parallel with the oil suction filter a and bypasses the oil suction oil circuit H and the booster pump oil suction oil circuit P1. The oil suction filter bypass valve e plays a role in preventing the oil suction filter from being blocked, that is, once the oil suction filter a is blocked, the hydraulic oil in the hydraulic oil tank 1 can also flow to the booster pump oil suction oil circuit P1 and the oil suction port of the booster pump 4 through the oil suction filter bypass valve e, so as to meet the pump suction flow demand in time.

[0050] Similarly, in this embodiment, a return oil filter bypass valve f is also provided, and the return oil filter bypass valve f bypasses the oil filter inlet connecting the oil suction oil circuit H and the return oil filter b. The return oil filter bypass valve f plays a role in preventing the return oil filter from being blocked, that is, once the return oil filter b is blocked, the return oil in the return oil circuit T1 of the main valve can flow back to the oil inlet of the suction filter a through the return oil filter bypass valve f, and can be pumped by the booster pump 4 through the suction filter a, or directly flow back to the hydraulic oil tank 1, so as to avoid the blockage of the return oil filter b causing the main valve return oil circuit T1 and the return oil port T of the main valve 6 to generate pressure build-up.

[0051] See also Figure 3 In another embodiment, the novel hydraulic system may further include an oil suction bypass valve 3, which is a back pressure valve and is bypass-connected between the booster pump oil suction circuit P1 and the oil suction port of the main pump 7. The hydraulic oil can flow from the oil suction port of the main pump 7 through the oil suction bypass valve 3 to the booster pump oil suction circuit P1 and is blocked in the reverse direction. Figure 3 In the figure, the oil suction bypass valve 3 adopts a one-way valve, and its back pressure is set to 1.5 bar, thereby limiting the positive oil suction pressure of the main pump 7, that is, the maximum oil pressure of the oil suction port of the main pump 7 does not exceed the set back pressure of the oil suction bypass valve 3, such as 1.5 bar as shown in the figure, otherwise the hydraulic oil with excessive pressure will flow back to the booster pump suction oil circuit P1 through the oil suction bypass valve 3, thus avoiding the problem of pressure imbalance and damage of the plunger pump caused by high oil suction pressure.

[0052] In this embodiment, the oil suction filter a is used as a coarse filter, and the return oil filter b is used as a fine filter. Since the cleanliness of the chassis housing oil tank is generally poor and the pump suction pressure is large, a coarse filter is used to quickly filter out large particles of impurities and meet the pump suction flow requirements. The return oil of the main valve return oil circuit T1 is the oil that participates in the work of actuators such as hydraulic cylinders and motors. After long-term use of the oil, some relatively fine impurities will inevitably exist, and the oil pressure of the main valve return oil circuit T1 is low. Therefore, the use of a fine filter can meet the fine filtration of the return oil and improve the cleanliness of the system oil. It should be noted that the coarse filtration and fine filtration here are relative, and are a comparison of filtration accuracy, that is, the minimum particle size of the coarse filtration is larger than the minimum particle size of the fine filtration, but the size of the minimum particle size is not specifically limited here.

[0053] In this embodiment, the set pumping flow rate of the booster pump 4 should be greater than the set pumping flow rate of the main pump 7, that is, the flow rate provided by the booster pump 4 should be greater than the required oil suction volume of the main pump 7. In this way, the pumped oil flow rate of the booster pump 4 will be able to meet the pumping demand of the main pump 7, and will not cause the hydraulic pump to suck empty, etc.

[0054] In addition, the hydraulic system of the present application may also include a radiator 5, which is arranged in the main valve return oil circuit T1 between the return oil filter b and the return oil port T of the main valve 6. The radiator 5 is used to dissipate heat for the system hydraulic oil to ensure the thermal balance of the system is stable. The radiator 5 is arranged in the main return oil circuit of the system (i.e., the main valve return oil circuit T1) with low oil pressure and sufficient flow, which can better play the role of heat dissipation of oil.

[0055] It can be seen that the hydraulic system of the present application can solve the problem of negative pressure in oil suction, so that the main pump maintains positive pressure oil suction; the new hydraulic system is more comprehensive and simple in function, and the oil suction and return oil filters are integrated into an integrated filtering device, which ensures the cleanliness of the suction oil and the return oil at the same time. The present application has a higher quality of control over the cleanliness of the system. The system has both an oil suction filter and an oil return filter, and the integrated design can minimize the amount of housing oil with poor cleanliness entering the system. The present application has a simple and efficient structure, low cost, a long filter element maintenance cycle, and simple and low cost replacement.

[0056] The hydraulic system of the present application can be applied to a tractor.

[0057] The hydraulic oil sucked from the hydraulic oil tank 1 by the booster pump 4 is provided to the main pump 7 as the oil suction source through the integrated filter 2. The hydraulic oil of the main pump 7 is provided to the main valve 6 of the tractor to be further distributed to various actuators to realize the linkage of various operations. The main valve 6 of the tractor is generally a multi-way valve. The LS port of the main valve 6 feeds back the load to the main pump 7 as a variable pump to adjust the pumping oil volume of the main pump and the flow distribution of the main valve 6. The return oil of each actuator passes through the main valve 6 and passes through the radiator 5 to provide heat dissipation for the entire system, and then passes through the integrated filter 2 to realize the oil circulation from the return oil to the suction oil.

[0058] Among them, the oil suction filter a in the integrated filter 2 is a coarse filter, the return oil filter is a fine filter b, the oil suction filter bypass valve e is for preventing the oil suction filter from clogging, and the return oil filter bypass valve f is for preventing the return oil filter from clogging. At the same time, it ensures that the oil distribution of the integrated filter 2 is balanced when the system return oil and oil suction are inconsistent. The return oil filter bypass oil is connected to the oil filter inlet of the oil suction filter to ensure that the bypassed oil enters the system after passing through the oil suction filter. The oil suction bypass valve 3 is used to limit the positive pressure of the plunger pump to avoid the high oil suction pressure causing the plunger pump to be damaged by pressure imbalance. The radiator 5 is for system heat dissipation to ensure the stability of the system thermal balance. Its return oil enters the oil suction port of the boost pump 4 through the return oil integrated filter 2. The return oil does not directly enter the chassis housing oil tank, which can minimize the transmission chassis housing oil with poor cleanliness from entering the system. The return oil integrated filter greatly reduces the use of the chassis housing oil tank, which can reduce the pressure of the housing oil volume. At the same time, the system cleanliness is maintained relatively stable, the maintenance time of the filter element is long, and the replacement is more convenient and quick.

[0059] In addition, in view of the poor cleanliness of the oil in the chassis housing oil tank of the tractor, in the process of using the chassis housing as an oil tank, considering the special needs such as oil replenishment and oil cleaning, an oil buffer chamber can be particularly provided in the chassis housing oil tank. At the same time, the oil filling port and the oil return port are both connected to the oil buffer chamber, that is, the oil suction oil circuit H is connected to the oil buffer chamber. Furthermore, a primary filter can be provided at the bottom of the oil buffer chamber, and the installation part and oil inlet part of the primary filter are both exposed in the oil buffer chamber, and the oil outlet part of the primary filter extends into the chassis housing oil tank. In this way, by providing the oil buffer chamber and the primary filter therein, the oil sucked into the hydraulic system and the oil returned to the oil tank can be prevented from being primarily filtered, and the oil impurities in the chassis housing oil tank can be prevented from directly entering the oil suction oil circuit H.

[0060] In particular, the oil injection port and the oil return port can be aligned with the primary filter, so that the installation position of the primary filter can disperse and buffer the oil injection and oil return to a certain extent, improve the efficiency of oil injection, oil absorption and filtration, and avoid local blockage.

[0061] This application adopts an integrated oil suction and return filter, in which the oil suction and oil return are integrated into a filtering device; it also adopts a new design of a positive pressure oil suction system, that is, an independent booster pump is added, and an oil suction bypass valve maintains the oil suction positive pressure range of the main pump; it also adopts a common oil system cleanliness control technology, with a simple system structure and high control cleanliness quality; finally, it also improves the adaptability to working conditions, has strong resistance to oil pollution, strong applicability to low temperature conditions, and strong adaptability to high speed and large flow conditions.

[0062] In the description of the present application, it should be understood that the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of the features. In the description of the present application, "plurality" means at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0063] In this application, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like 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, an electrical connection, or communication with each other; it can be a direct connection, or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0064] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0065] Although the embodiments of the present application have been shown and described above, it can be understood that the above embodiments are exemplary and cannot be understood as limitations on the present application. Ordinary technicians in this field can change, modify, replace and modify the above embodiments within the scope of the present application.

Claims

1. A hydraulic system, characterized in that: The hydraulic system comprises: A hydraulic oil tank (1) and a main valve (6), wherein the oil return port (T) of the main valve (6) is connected to a main valve oil return circuit (T1); A hydraulic pump group, comprising a booster pump (4) and a main pump (7) arranged in series, wherein the main pump (7) is arranged on the oil outlet side of the booster pump (4) and is used to supply oil to the oil inlet (P) of the main valve (6); An integrated filter (2) comprises an oil suction filter (a) and an oil return filter (b) arranged in an oil return oil circuit (T1) of a main valve, wherein an oil filter inlet of the oil suction filter (a) is connected to the hydraulic oil tank (1) via an oil suction oil circuit (H); A booster pump oil suction circuit (P1) is connected between the oil filter outlet of the oil suction filter (a) and the oil suction port of the booster pump (4), and the oil filter outlet of the return oil filter (b) is hydraulically connected to the booster pump oil suction circuit (P1).

2. The hydraulic system according to claim 1, characterized in that: The integrated filter (2) further comprises: An oil suction filter bypass valve (e) is connected in parallel with the oil suction filter (a) and bypasses the oil suction oil circuit (H) and the booster pump oil suction oil circuit (P1).

3. The hydraulic system according to claim 2, characterized in that: The integrated filter (2) further comprises: The return oil filter bypass valve (f) bypasses the oil filter inlet connecting the oil suction circuit (H) and the return oil filter (b).

4. The hydraulic system according to any one of claims 1 to 3, characterized in that: The hydraulic system comprises: An oil suction bypass valve (3), the oil suction bypass valve (3) being a back pressure valve and being bypass-connected between the oil suction oil circuit (P1) of the booster pump and the oil suction port of the main pump (7); The hydraulic oil can flow from the oil suction port of the main pump (7) through the oil suction bypass valve (3) to the booster pump oil suction oil circuit (P1) and is blocked in the reverse direction.

5. The hydraulic system according to claim 1, characterized in that: The hydraulic oil tank (1) is a chassis housing oil tank.

6. The hydraulic system according to claim 1, characterized in that: The oil suction filter (a) is a coarse filter, and the oil return filter (b) is a fine filter.

7. The hydraulic system according to claim 1, characterized in that: The hydraulic oil tank (1) is a chassis housing oil tank.

8. The hydraulic system according to claim 1, characterized in that: The set pumping flow rate of the booster pump (4) is greater than the set pumping flow rate of the main pump (7).

9. The hydraulic system according to claim 1, characterized in that: The hydraulic system comprises: The radiator (5) is arranged in the main valve oil return path (T1) between the oil return filter (b) and the oil return port (T) of the main valve (6).

10. A tractor, characterized in that: The tractor comprises a hydraulic system according to any one of claims 1 to 9.

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