Hydraulic walking system and wheel type harvester

Abstract

The utility model discloses a hydraulic walking system and a wheel type harvester. The hydraulic walking system comprises a front axle variable displacement motor and a front axle gearbox used for driving the wheel type harvester. The rear axle variable displacement motor is used for driving a rear axle gearbox of the wheel type harvester; the displacement control valve group comprises a first displacement control valve for controlling the displacement of the front axle variable displacement motor and a second displacement control valve for controlling the displacement of the rear axle variable displacement motor; the walking pump is used for pumping hydraulic oil to the front axle variable displacement motor and the rear axle variable displacement motor which are arranged in parallel. The hydraulic walking system of the wheel type harvester is small in generated pressure loss, smaller in heating, high in control precision, low in slipping rate, capable of adapting to different gears and better in working condition adaptability. The system can analyze and distinguish collected related data according to actual working conditions and then perform automatic regulation and control, so that a better automatic regulation effect can be achieved.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of agricultural machinery, and in particular, relates to a wheeled harvester and a hydraulic walking system thereof. BACKGROUND

[0002] Most of the current wheeled grain combines (referred to as wheeled harvesters) adopt a hydrostatic walking system, including a hydrostatic two-drive walking system and a hydrostatic four-drive walking system. Among them, for the hydrostatic four-drive walking system, since the driving force of the front axle is greater than that of the rear axle, in the case of small ground adhesion, the front axle will slip, thereby reducing the pressure of the entire hydraulic walking system and the driving force of the whole vehicle. SUMMARY

[0003] The purpose of the present application is to provide a hydraulic walking system and a wheeled harvester to improve the walking performance and control performance of the whole machine.

[0004] To achieve the above purpose, the present application provides a hydraulic walking system suitable for a wheeled harvester, the hydraulic walking system comprising:

[0005] a front axle variable motor for driving a front axle gearbox of the wheeled harvester;

[0006] a rear axle variable motor for driving a rear axle gearbox of the wheeled harvester;

[0007] a displacement control valve group comprising a first displacement control valve for controlling the displacement of the front axle variable motor and a second displacement control valve for controlling the displacement of the rear axle variable motor;

[0008] a walking pump for pumping hydraulic oil for the front axle variable motor and the rear axle variable motor arranged in parallel.

[0009] In some embodiments, the front axle variable motor comprises a front axle motor control plunger for controlling the flow rate of the motor, the first displacement control valve comprises a first connection oil port on one side and a second connection oil port and a return oil port on the other side, and is used for controlling the first connection oil port to selectively connect the second connection oil port or the return oil port; wherein the first connection oil port is hydraulically connected to the rodless cavity of the front axle motor control plunger, and the second connection oil port is hydraulically connected to the rod cavity of the front axle motor control plunger.

[0010] In some embodiments, the two end oil ports of the front axle variable motor are respectively hydraulically connected to the second connection oil port through a supplementary oil path provided with a supplementary oil one-way valve.

[0011] In some embodiments, the first displacement control valve is a proportional solenoid valve of a spool structure.

[0012] In some embodiments, the second displacement control valve is a two-position four-way solenoid valve.

[0013] In some embodiments, the rear axle variable motor includes a rear axle motor control spool for controlling motor flow, and the second displacement control valve includes:

[0014] a two-position four-way solenoid valve, one side port of the two-position four-way solenoid valve being an inlet port and a return port, and the other side port including a first outlet port connected to a rod chamber of the rear axle motor control spool and a second outlet port connected to a rodless chamber of the rear axle motor control spool, the inlet port being configured to selectively communicate with the first outlet port or the second outlet port.

[0015] In some embodiments, the first displacement control valve further includes:

[0016] a shuttle valve, two comparison ports of the shuttle valve being hydraulically connected to two end ports of the rear axle variable motor, and an outlet port of the shuttle valve being hydraulically connected to the inlet port of the two-position four-way solenoid valve.

[0017] In some embodiments, the two-position four-way solenoid valve is a proportional solenoid valve.

[0018] In some embodiments, the hydraulic travel system includes:

[0019] a rear axle speed sensor configured to detect a rotational speed of the rear axle variable motor;

[0020] a front axle speed sensor configured to detect a rotational speed of the front axle variable motor;

[0021] a pressure sensor disposed in a pump delivery path from an outlet port of the travel pump to the front axle variable motor and the rear axle variable motor.

[0022] In some embodiments, the hydraulic travel system includes a controller in communication with the rear axle speed sensor, the front axle speed sensor, and the pressure sensor, the controller being configured to:

[0023] determine that the second displacement control valve is in an all-wheel drive control mode in which the rear axle variable motor has a displacement greater than zero;

[0024] determine that a rotational speed difference between a front axle detected rotational speed of the front axle speed sensor and a rear axle detected rotational speed of the rear axle speed sensor is greater than a set rotational speed difference;

[0025] control the first displacement control valve to adjust a displacement of the front axle variable motor until the rotational speed difference is not greater than the set rotational speed difference.

[0026] In some embodiments, the controller is further configured to:

[0027] in response to the high-speed transition signal, control the second displacement control valve to switch to a two-drive control mode in which the displacement of the rear axle variable motor is zero.

[0028] In some embodiments, the hydraulic travel system comprises a controller in communication with the rear axle speed sensor, the front axle speed sensor, and the pressure sensor, the controller configured to:

[0029] determine that the second displacement control valve is in a two-drive control mode in which the displacement of the rear axle variable motor is zero;

[0030] determine that the system pressure value detected by the pressure sensor is below a set pressure value, and determine that the front axle detected rotational speed of the front axle speed sensor is below a set front axle rotational speed;

[0031] control the second displacement control valve to switch to a four-drive control mode in which the displacement of the rear axle variable motor is greater than zero.

[0032] Further, the present application also provides a wheel harvester comprising the above hydraulic travel system.

[0033] In the wheel harvester and the hydraulic travel system thereof of the present application, the driving sources of the front and rear axles are variable motors, and the variable motors control the displacement through displacement control valves, so as to accurately control the flow and rotational speed of the front and rear axles, to realize the accurate flow distribution of the pumped oil of the travel pump in the front and rear axles. Compared with the existing forced distribution mode, the pressure loss caused by the flow control mode of the variable motor is small, the heat generation is smaller, and the control precision is higher. By controlling the displacement control valve, the two-drive and four-drive control modes can be switched. In the two-drive control mode, it is helpful for high-speed transition and other operations, and in the four-drive control mode, it can adapt to the climbing working condition and improve the driving force of the whole vehicle, so as to improve the travel performance and working condition adaptability of the harvester.

[0034] Other advantages of the present application and technical effects of the preferred embodiments will be further described in the specific embodiments below. BRIEF DESCRIPTION OF DRAWINGS

[0035] The accompanying drawings are included to provide a further understanding of the embodiments of the present application, and constitute a part of the specification, and are used to explain the embodiments of the present application together with the specific embodiments below, but do not constitute a limitation on the embodiments of the present application. For those skilled in the art, other drawings can also be obtained from the structures shown in the drawings without creative labor. In the drawings:

[0036] Figure 1 a hydraulic schematic diagram of the hydraulic travel system of the harvester in the prior art;

[0037] Figure 2 Fig. 1 is a hydraulic schematic diagram of a hydraulic walking system of a harvester according to an embodiment of the present application;

[0038] Figure 3 Fig. 2 is a partial enlarged view of a front axle portion in Fig. 1 ; Figure 2

[0039] Figure 4 Fig. 3 is a partial enlarged view of a rear axle portion in Fig. 1 ; Figure 2

[0040] Figure 5 Fig. 4 is a hydraulic schematic diagram of a rear axle portion in a hydraulic walking system according to another embodiment of the present application.

[0041] BRIEF DESCRIPTION OF DRAWINGS

[0042] 1 walking pump 2 rear axle transmission

[0043] 3 rear axle speed sensor 4 rear axle variable motor

[0044] 5 two-position four-way solenoid valve 6 front axle variable motor

[0045] 7 front axle transmission 8 first displacement control valve

[0046] 9 front axle speed sensor 10 pressure sensor

[0047] 11 oil supplement check valve 12 shuttle valve

[0048] 13 electromagnetic reversing valve

[0049] 41 rear axle motor control plunger 61 front axle motor control plunger

[0050] A1 first connection oil port A2 second connection oil port

[0051] T oil return port B oil inlet port

[0052] C1 first oil outlet port C2 second oil outlet port DETAILED DESCRIPTION

[0053] The specific embodiments of the present application will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are merely intended to illustrate and explain the present application, and are not intended to limit the present application. It should be noted that the embodiments in the present application and the features in the embodiments can be combined with each other without conflict.

[0054] The hydraulic walking system and the wheeled harvester of the present application will be described in detail below with reference to the accompanying drawings and in conjunction with the embodiments.

[0055] The present application discloses a new type of hydraulic walking system suitable for a wheeled harvester. In the hydraulic walking system,​​Figure 2 In the specific embodiment shown, the hydraulic travel system comprises:

[0056] a front axle variable motor 6 for driving a front axle gearbox 7 of the wheel harvester;

[0057] a rear axle variable motor 4 for driving a rear axle gearbox 2 of the wheel harvester;

[0058] a displacement control valve group comprising a first displacement control valve 8 for controlling the displacement of the front axle variable motor 6 and a second displacement control valve for controlling the displacement of the rear axle variable motor 4;

[0059] a travel pump 1 for pumping hydraulic oil for the front axle variable motor 6 and the rear axle variable motor 4 arranged in parallel.

[0060] In the hydraulic travel system of the present embodiment, a variable motor is particularly adopted to drive the front and rear axles respectively, and the displacement of each motor is controlled by a respective displacement control valve, so that the rotational speed of the front and rear axles can be accurately adjusted to adapt to different working conditions such as slipping; moreover, by controlling the displacement of the rear axle variable motor 4 to be zero or a non-zero state, that is, by making the pumped hydraulic oil of the travel pump 1 be pumped to the front axle alone or be split to the front and rear axles, the system can also be easily switched between two-wheel drive or four-wheel drive control modes. Compared with the forced split mode, the flow control mode of the variable motor in the present system has smaller pressure loss, smaller heat generation, higher control precision, and can adapt to different working conditions such as slipping, climbing, high speed, etc., and has stronger adaptability, so that the travel performance of the whole machine is improved, which will be described in detail below.

[0061] Comparatively, the static hydraulic travel system in the prior art mostly adopts a forced split mode to solve the slipping problem. For example, Figure 1As shown, the hydrostatic drive anti-slip control system disclosed in Chinese patent application CN217064642U includes a hydraulic pump 01, a first hydraulically controlled three-way valve 02, a second hydraulically controlled three-way valve 03, a first hydraulic motor 04, and a second hydraulic motor 05. The output end of the hydraulic pump 01 is connected via pipelines to the left hydraulic inlet of the first hydraulically controlled three-way valve 02 and the right hydraulic inlet of the second hydraulically controlled three-way valve 03. The second left hydraulic outlet of the second hydraulically controlled three-way valve 03 is connected via pipelines to the first hydraulic motor 04 and the first right hydraulic outlet of the second hydraulically controlled three-way valve 03. The second right hydraulic outlet of the second hydraulically controlled three-way valve 03 is connected via pipelines to the second hydraulic motor 05 and the first left hydraulic outlet of the first hydraulically controlled three-way valve 02. The first hydraulic motor 04 and the second hydraulic motor 05 are also connected via pipelines to the input end of the hydraulic pump 01. By using the first hydraulically controlled three-way valve 02 and the second hydraulically controlled three-way valve 03 to regulate the hydraulic flow, the purpose of anti-slip is achieved. However, this method of forced flow diversion using a three-way valve results in significant pressure loss and severe heat generation; moreover, the three-way valve has low precision and poor slippage control; the three-way valve is generally a fixed flow diversion ratio and cannot adapt to different gearbox gears, and it is also difficult to automatically adjust.

[0062] This application aims to solve the problem of front axle slippage under low adhesion conditions, reduce pressure loss, and provide adaptive adjustment to further improve anti-slip efficiency. See also Figure 2 One oil port of the travel pump 1 ( Figure 1 The oil port on the right side is connected to port A of the front axle variable motor 6 and the rear axle variable motor 4 via two hydraulic lines. The other oil port of the travel pump 1 is connected to port B of the front axle variable motor 6 and the rear axle variable motor 4 via a hydraulic line. The first displacement control valve 8 can be integrated into the front axle variable motor 6, and the second displacement control valve can be integrated into the rear axle variable motor 4. The second displacement control valve can be used to switch between two-wheel drive and four-wheel drive control modes, and the first displacement control valve 8 can be used to control the displacement of the front axle variable motor 6. Thus, by controlling the current of the displacement control valve (which acts as a solenoid valve), the flow rate through the corresponding variable motor can be precisely controlled. This allows for precise control of the motor speed while simultaneously achieving precise flow control of the pumped hydraulic oil from the travel pump 1 to the front axle variable motor 6 and the rear axle variable motor 4. Large-flow pumped hydraulic oil flows entirely within the main hydraulic lines without passing through any diversion valves, resulting in minimal pressure loss and no heat generation.

[0063] As is known to those skilled in the art, similar to variable pumps, variable motors can also have different structural forms, especially their flow control components. In this embodiment, the variable motors are all plunger type, but this application is not limited to this. As an example, see [link to example]. Figure 3The front axle variable motor 6 of the embodiment includes a front axle motor control plunger 61 for controlling the flow rate of the motor, and the first displacement control valve 8 includes a first connection oil port A1 on one side (the left side of the valve in the figure) and a second connection oil port A2 and a return oil port T on the other side, and is used to control the first connection oil port A1 to selectively connect the second connection oil port A2 or the return oil port T; wherein the first connection oil port A1 is hydraulically connected to the rodless cavity of the front axle motor control plunger 61, and the second connection oil port A2 is hydraulically connected to the rod cavity of the front axle motor control plunger 61.

[0064] At the upper valve position of the first displacement control valve 8, the first connection oil port A1 is communicated with the return oil port T, and the second connection oil port A2 is cut off, at this time the rodless cavity of the front axle motor control plunger 61 returns oil, and the plunger rod of the front axle motor control plunger 61 retracts to the extreme value. When the electromagnet is powered, the first displacement control valve 8 switches to the lower valve position, the first connection oil port A1 is communicated with the second connection oil port A2, and the return oil port T is cut off, at this time the rodless cavity and the rod cavity of the front axle motor control plunger 61 are communicated, and because the plunger rod area of the rodless cavity is large, the plunger rod is driven to extend to the extreme value. The extension and retraction of the plunger rod will drive the flow distribution plate to move to control the flow rate. In this way, by controlling whether the first displacement control valve 8 is powered or not, the flow rate of the front axle variable motor 6 is switched between zero and maximum.

[0065] In particular, the two end ports of the front axle variable motor 6 are hydraulically connected to the second connection oil port A2 through the oil supplementing oil path provided with the oil supplementing one-way valve 11. Therefore, the high pressure oil in the two end ports of the front axle variable motor 6 will be drained to the rod cavity of the front axle motor control plunger 61 through the oil supplementing one-way valve 11, so that the rod cavity maintains a certain pressure, and there is no virtual displacement stroke in the extension and retraction of the plunger rod, and the flow rate control of the variable motor has continuity and smoothness. At the lower valve position of the first displacement control valve 8, a certain pressure exists in the rodless cavity and the rod cavity to drive the plunger rod to extend; at the upper valve position of the first displacement control valve 8, when the plunger rod retracts, hydraulic oil can be supplemented to the rod cavity.

[0066] In the embodiment, Figure 3 The first displacement control valve 8 shown is a two-position three-way electromagnetic valve. But obviously it is not limited to this, the first displacement control valve 8 can also adopt a proportional electromagnetic valve with a spool structure to realize more accurate control of the extension and retraction of the plunger rod.

[0067] The second displacement control valve is used to control the flow rate of the rear axle variable motor 4. In some working conditions, only the flow rate of the rear axle variable motor 4 needs to be controlled to be zero or rated, at this time the second displacement control valve can be a on-off electromagnetic valve for controlling the opening and closing of the rear axle variable motor 4. Of course, in some working conditions, it is also necessary to accurately adjust the flow rate of the rear axle variable motor 4, at this time the second displacement control valve can be a proportional electromagnetic valve.

[0068] Referring toFigure 4 In the present embodiment, the rear axle variable motor 4 includes a rear axle motor control spool 41 for controlling the flow rate of the motor. As an example, the second displacement control valve can include:

[0069] A two-position four-way solenoid valve 5, one side of the two-position four-way solenoid valve 5 is an inlet port B and a return port T, the other side includes a first outlet port C1 connected to the rod chamber of the rear axle motor control spool 41 and a second outlet port C2 connected to the rodless chamber of the rear axle motor control spool 41, the inlet port B is used to selectively communicate the first outlet port C1 or the second outlet port C2.

[0070] Here also uses a solenoid valve to selectively introduce pressure oil into the rod chamber or the rodless chamber of the rear axle motor control spool 41, thereby controlling the extension or retraction of the spool rod of the rear axle motor control spool 41. As shown in Figure 4 When the solenoid valve is energized, the two-position four-way solenoid valve 5 is in the lower valve position, the inlet port B is bypassed to the first outlet port C1, i.e. the pressure oil is introduced into the rod chamber, at the same time the second outlet port C2 is communicated with the return port T to return oil, pushing the spool rod to retract. Similarly, when the solenoid valve is de-energized, the two-position four-way solenoid valve 5 switches to the upper valve position, the inlet port B communicates with the second outlet port C2, i.e. the pressure oil is introduced into the rodless chamber, pushing the spool rod to extend, at the same time the first outlet port C1 communicates with the return port T to return oil. In this way, by controlling whether the two-position four-way solenoid valve 5 is energized or not, the flow rate of the rear axle variable motor 4 can be switched between zero and maximum.

[0071] The first displacement control valve 8 can also include a shuttle valve 12, the two comparison ports of the shuttle valve 12 are respectively hydraulically connected to the two end ports of the rear axle variable motor 4, and the outlet port of the shuttle valve 12 is hydraulically connected to the inlet port B of the two-position four-way solenoid valve 5. In other words, the inlet oil of the two-position four-way solenoid valve 5 comes from the pressure of the two end ports of the rear axle variable motor 4. Of course, alternatively, the pressure oil of the system pilot oil circuit or the working oil circuit can also be introduced to the inlet port B of the two-position four-way solenoid valve 5. Among them, the two-position four-way solenoid valve 5 can also be a proportional solenoid valve.

[0072] The second displacement control valve can also have other structural forms. As an example, referring to Figure 5 , the second displacement control valve adopts a structural form similar to the first displacement control valve 8 shown in Figure 3 , i.e. a two-position four-way solenoid reversing valve 13, which has the same effect as the two-position four-way solenoid valve 5 of Figure 4 , except that Figure 4 The pressure oil of the two-position four-way solenoid valve 5 of Figure 5 is taken from the working oil circuit of the variable motor through the shuttle valve 12, while the pressure oil of the solenoid reversing valve 13 of

[0073] It can be seen that in some embodiments, the second displacement control valve can be designed as an on-off valve to on-off control the rear axle variable motor 4, while the first displacement control valve is designed as a proportional valve, so that the flow of the front axle variable motor 6 can be continuously proportionally adjusted. Of course, as mentioned above, the present application is not limited thereto, and both the first and second displacement control valves can be proportional valves, etc.

[0074] In addition, the hydraulic traveling system of the present embodiment can further include:

[0075] a rear axle speed sensor 3 for detecting the rotational speed of the rear axle variable motor 4;

[0076] a front axle speed sensor 9 for detecting the rotational speed of the front axle variable motor 6;

[0077] a pressure sensor 10 arranged in the pumping oil path from the oil outlet of the traveling pump 1 to the front axle variable motor 6 and the rear axle variable motor 4.

[0078] Through the arrangement of the sensors, the rotational speeds of the front and rear axles and the pressure of the hydraulic system can be detected respectively, so that different working conditions can be determined, and the variable motors can be controlled and distributed in a targeted manner.

[0079] On this basis, the hydraulic traveling system can include a controller in communication with the rear axle speed sensor 3, the front axle speed sensor 9 and the pressure sensor 10, and the controller is configured to:

[0080] determine that the second displacement control valve is in a four-wheel drive control mode in which the displacement of the rear axle variable motor 4 is greater than zero;

[0081] determine that the rotational speed difference between the front axle detection speed of the front axle speed sensor 9 and the rear axle detection speed of the rear axle speed sensor 3 is greater than a set rotational speed difference;

[0082] control the first displacement control valve 8 to adjust the displacement of the front axle variable motor 6 until the rotational speed difference is not greater than the set rotational speed difference.

[0083] It can be seen that in the four-wheel drive control mode, the front and rear axle variable motors are operated under flow driving to adapt to the slipping working condition. The controller collects the values of the rear axle speed sensor 3 and the front axle speed sensor 9 in real time, and once the speed difference between the front axle detection speed and the rear axle detection speed is too large, for example, greater than a certain set value, it can be confirmed that the front axle slipping condition occurs. As a countermeasure, the displacement of the front axle variable motor 6 can be adjusted, i.e. the hydraulic flow to the front axle is limited, and at the same time the hydraulic flow to the rear axle is increased to improve the rear drive force and solve the slipping problem.

[0084] When the displacement of the front axle variable motor 6 is adjusted by the first displacement control valve 8, the speed difference between the front axle detected speed and the rear axle detected speed can be monitored so that the speed difference value approaches a preset value, and when the preset value is reached, the adjustment of the displacement of the front axle variable motor 6 is stopped. Of course, in order to protect the front axle variable motor 6, the adjustment of the displacement of the front axle variable motor 6 can also be limited.

[0085] In the high-speed turning field working condition, the controller can also be configured to:

[0086] In response to the high-speed turning signal, the second displacement control valve is controlled to switch to the two-drive control mode in which the displacement of the rear axle variable motor 4 is zero.

[0087] It can be seen that when high-speed turning is required, only the displacement of the rear axle variable motor 4 is changed to zero by the second displacement control valve, and the four-wheel drive control mode is switched to the two-wheel drive control mode, so that the walking speed is improved and high-speed turning is realized.

[0088] In addition, the controller can also be configured to:

[0089] determine that the second displacement control valve is in the two-drive control mode in which the displacement of the rear axle variable motor 4 is zero;

[0090] determine that the system pressure value detected by the pressure sensor 10 is lower than the set pressure value, and determine that the front axle detected speed of the front axle speed sensor 9 is lower than the set front axle speed;

[0091] control the second displacement control valve to switch to the four-wheel drive control mode in which the displacement of the rear axle variable motor 4 is greater than zero.

[0092] In the two-wheel drive control mode, the displacement of the front axle variable motor 6 is not controlled and is in a fixed displacement; in the working or climbing condition, when the displacement of the walking pump 1 is not zero, the system pressure is collected by the pressure sensor 10, and when the detected system pressure suddenly decreases to a certain set value and the speed value collected by the front axle speed sensor 9 is lower than a certain value, the four-wheel drive can be automatically turned on to improve the driving force of the whole vehicle. Therefore, in the two-wheel drive control mode, in order to adapt to the working or climbing condition, the second displacement control valve can be switched to the four-wheel drive control mode to improve the driving force of the whole vehicle. Through the above different control strategies, the walking performance and working condition adaptability of the harvester can be greatly improved.

[0093] The application also discloses a wheel type harvester comprising the hydraulic walking system.

[0094] In the description of the application, it should be understood that the terms "first", "second" are only for the purpose of description, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first", "second" can be explicitly or implicitly included at least one of the features. In the description of the application, the meaning of "a plurality of" is at least two, such as two, three, etc., unless otherwise specifically limited.

[0095] In the present application, unless otherwise expressly specified and limited, the terms "mounting", "connecting", "connecting", "fixing" and the like should be understood in a broad sense, for example, it can be fixedly connected, or it can be detachably connected, or it can be integrated; it can be mechanically connected, or it can be electrically connected or communicate with each other; it can be directly connected, or it can be indirectly connected through an intermediate medium, it can be the internal communication of two elements or the interaction relationship between two elements, unless otherwise expressly limited. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0096] In the description of the present application, the description of the terms "one embodiment", "some embodiments", "example", "specific example" or "some examples" 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 the present application, the illustrative description of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any appropriate manner in any one or more embodiments or examples. In addition, those skilled in the art can combine and combine the different embodiments or examples described in the present application and the features of different embodiments or examples without contradiction.

[0097] Although the embodiments of the present application have been shown and described above, it should be understood that the above embodiments are exemplary and cannot be understood as limiting the present application, and those skilled in the art can make changes, modifications, replacements and variations to the above embodiments within the scope of the present application.

Claims

1. A hydraulic walking system suitable for wheeled harvesters, characterized in that, The hydraulic walking system includes: A front axle variable motor (6) is used to drive the front axle gearbox (7) of a wheeled harvester; A rear axle variable motor (4) is used to drive the rear axle gearbox (2) of the wheeled harvester; The displacement control valve assembly includes a first displacement control valve (8) for controlling the displacement of the front axle variable motor (6) and a second displacement control valve for controlling the displacement of the rear axle variable motor (4). The travel pump (1) is used to pump hydraulic oil for the front axle variable motor (6) and the rear axle variable motor (4) that are connected in parallel.

2. The hydraulic walking system according to claim 1, characterized in that, The front axle variable displacement motor (6) includes a front axle motor control plunger (61) for controlling the flow rate of the motor. The first displacement control valve (8) includes a first connecting port (A1) on one side and a second connecting port (A2) and a return port (T) on the other side, and is used to control the first connecting port (A1) to selectively connect to the second connecting port (A2) or the return port (T). The first connecting port (A1) is hydraulically connected to the rodless chamber of the front axle motor control plunger (61), and the second connecting port (A2) is hydraulically connected to the rod chamber of the front axle motor control plunger (61).

3. The hydraulic walking system according to claim 2, characterized in that, The two ends of the front axle variable motor (6) are hydraulically connected to the second connection port (A2) through a replenishment oil circuit equipped with a replenishment oil check valve (11).

4. The hydraulic walking system according to claim 2, characterized in that, The first displacement control valve (8) is a proportional solenoid valve with a slide valve structure.

5. The hydraulic walking system according to claim 1, characterized in that, The second displacement control valve is a switching solenoid valve used to control the opening and closing of the rear axle variable motor (4).

6. The hydraulic walking system according to claim 1, characterized in that, The rear axle variable displacement motor (4) includes a rear axle motor control plunger (41) for controlling the flow rate through the motor, and the second displacement control valve includes: A two-position four-way solenoid valve (5) has an oil inlet (B) and an oil return (T) on one side, and an oil outlet (C2) on the other side, which includes a first oil outlet (C1) connected to the rod chamber of the rear axle motor control plunger (41) and a second oil outlet (C2) connected to the rodless chamber of the rear axle motor control plunger (41). The oil inlet (B) is used to selectively connect to the first oil outlet (C1) or the second oil outlet (C2).

7. The hydraulic walking system according to claim 6, characterized in that, The first displacement control valve (8) further includes: The shuttle valve (12) has two comparison ports hydraulically connected to the two ends of the rear axle variable motor (4), and the outlet of the shuttle valve (12) is hydraulically connected to the inlet (B) of the two-position four-way solenoid valve (5).

8. The hydraulic walking system according to claim 6, characterized in that, The two-position four-way solenoid valve (5) is a proportional solenoid valve.

9. The hydraulic walking system according to any one of claims 1 to 8, characterized in that, The hydraulic walking system includes: The rear axle speed sensor (3) is used to detect the rotational speed of the rear axle variable motor (4); A front axle speed sensor (9) is used to detect the rotational speed of the front axle variable motor (6); A pressure sensor (10) is installed in the pumping oil circuit from the oil outlet of the travel pump (1) to the front axle variable motor (6) and the rear axle variable motor (4).

10. The hydraulic walking system according to claim 9, characterized in that, The hydraulic walking system includes a controller that communicates with the rear axle speed sensor (3), the front axle speed sensor (9), and the pressure sensor (10), the controller being configured to: Determine that the second displacement control valve is in a four-wheel drive control mode that makes the displacement of the rear axle variable motor (4) greater than zero; The speed difference between the front axle detection speed of the front axle speed sensor (9) and the rear axle detection speed of the rear axle speed sensor (3) is determined to be greater than a set speed difference value; Control the first displacement control valve (8) to adjust the displacement of the front axle variable motor (6) until the speed difference is not greater than the set speed difference.

11. The hydraulic walking system according to claim 10, characterized in that, The controller is also configured to: In response to the high-speed transfer signal, the second displacement control valve is controlled to switch to the two-drive control mode that makes the displacement of the rear axle variable motor (4) zero.

12. The hydraulic walking system according to claim 9, characterized in that, The hydraulic walking system includes a controller that communicates with the rear axle speed sensor (3), the front axle speed sensor (9), and the pressure sensor (10), the controller being configured to: Determine that the second displacement control valve is in a two-drive control mode that makes the displacement of the rear axle variable motor (4) zero; It is determined that the system pressure value detected by the pressure sensor (10) is lower than the set pressure value, and that the front axle speed detected by the front axle speed sensor (9) is lower than the set front axle speed; Control the second displacement control valve to switch to a four-wheel drive control mode that makes the displacement of the rear axle variable motor (4) greater than zero.

13. A wheeled harvester, characterized in that, The wheeled harvester includes a hydraulic walking system according to any one of claims 1 to 12.

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