Track hydraulic system and hydraulic excavator

Abstract

The utility model belongs to the field of engineering machinery, and discloses a crawler hydraulic system and a hydraulic excavator. The crawler hydraulic system comprises a walking hydraulic loop, the walking hydraulic loop comprises a walking motor, a main valve and a walking balance valve, and the walking balance valve is arranged in a motor working oil way between the walking motor and the main valve; the tensioning hydraulic loop comprises a tensioning oil cylinder used for tensioning the crawler belt and a tensioning valve group used for controlling the tensioning oil cylinder; and the tensioning hydraulic loop is in bypass connection to the motor working oil way between the walking balance valve and the main valve. The tensioning hydraulic loop is connected into the walking hydraulic loop in a bypass mode, tensioning of the tensioning oil cylinder is achieved by introducing oil liquid entering the walking motor, and therefore an independent hydraulic pump does not need to be arranged to supply oil to the whole tensioning hydraulic loop, a hydraulic system is simplified, and energy consumption is reduced.

Description

Technical Field

[0001] This application belongs to the field of construction machinery, specifically relating to a tracked hydraulic system and a hydraulic excavator. Background Technology

[0002] For hydraulic excavators, especially ultra-large tonnage excavators, track tension is crucial for the normal operation and safety of the excavator. For example... Figure 1 As shown, existing track hydraulic tensioning is generally achieved through accumulators and tensioning cylinders, but requires a separate hydraulic pump to supply oil to the entire tensioning hydraulic system, making the hydraulic system more complex, with more hydraulic components, not integrated, inconvenient to arrange, and posing certain risks during maintenance and disassembly. Summary of the Invention

[0003] The purpose of this application is to provide a tracked hydraulic system and a hydraulic excavator to simplify the hydraulic system configuration, improve system compactness, and reduce energy consumption.

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

[0005] The travel hydraulic circuit includes a travel motor, a main valve, and a travel balance valve, wherein the travel balance valve is disposed in the motor working oil circuit between the travel motor and the main valve;

[0006] The tensioning hydraulic circuit includes a tensioning cylinder for tensioning the track and a tensioning valve assembly for controlling the tensioning cylinder;

[0007] The tensioning hydraulic circuit is bypassed and connected to the motor working oil circuit between the walking balance valve and the main valve.

[0008] In some embodiments, the walking balance valve includes:

[0009] A hydraulically controlled directional valve, wherein the pilot control oil circuit of the hydraulically controlled directional valve is hydraulically connected to the motor working oil circuit connected to the tensioning valve assembly.

[0010] In some embodiments, the tensioning hydraulic circuit includes:

[0011] An accumulator is hydraulically connected to the pressure chamber of the tensioning cylinder.

[0012] In some embodiments, the tensioning valve assembly includes:

[0013] The pressure reducing valve allows the hydraulic oil in the motor's working oil circuit to flow into the pressure chamber of the tensioning cylinder after passing through the pressure reducing valve.

[0014] In some embodiments, the walking balance valve includes a pressure-holding relief valve, wherein the relief pressure setting of the pressure-holding relief valve is greater than the pressure setting of the pressure-reducing valve.

[0015] In some embodiments, the tensioning valve assembly includes:

[0016] A first check valve is disposed before the pressure reducing valve and is used to prevent oil in the tensioning hydraulic circuit from flowing back into the motor working oil circuit.

[0017] In some embodiments, the tensioning valve assembly includes:

[0018] The oil relief valve is hydraulically connected in the oil circuit between the pressure chamber of the tensioning cylinder and the pressure reducing valve.

[0019] In some embodiments, the track hydraulic system includes:

[0020] A pressure sensor is used to detect the oil pressure in the pressure chamber of the tensioning cylinder;

[0021] The controller is configured as follows:

[0022] It is determined that the walking motor is in a continuous working state, and the oil pressure detected by the pressure sensor is continuously less than the set value of the pressure reducing valve for a set time.

[0023] If the problem is determined to be a component failure or leak, an alarm will be triggered for repair.

[0024] Ensure that the oil pressure detected by the pressure sensor is not less than the set overflow value of the oil relief valve;

[0025] Identify abnormal operating conditions and trigger an alarm for repair.

[0026] In some embodiments, the tensioning valve assembly includes:

[0027] An adjustable throttle valve is connected in parallel with the drain relief valve and is used to throttle the return oil in the pressure chamber of the tensioning cylinder; and / or

[0028] The second check valve is located after the pressure reducing valve and is used to prevent the oil in the pressure chamber of the tensioning cylinder from flowing back.

[0029] In addition, this application also provides a hydraulic excavator, which includes the above-described track hydraulic system.

[0030] In the tracked hydraulic system and hydraulic excavator of this application, a separate hydraulic pump is no longer used to supply oil to the entire tensioning system. Instead, the tensioning hydraulic circuit with tensioning valve assembly is bypassed and connected to the travel hydraulic circuit, that is, hydraulically connected to the motor working oil circuit between the travel balance valve and the main valve. This saves on the number of hydraulic pumps, simplifies the hydraulic system, reduces energy consumption, and allows for high integration of various hydraulic components by reducing the number of hydraulic pumps and other hydraulic components, making the system layout more convenient and concise.

[0031] Other advantages of this application and the technical effects of preferred embodiments will be further described in the detailed embodiments below. Attached Figure Description

[0032] The accompanying drawings are provided to illustrate the present application and form part of the specification. They are used together with the following detailed description to explain the present application, but do not constitute a limitation thereof. In the drawings:

[0033] Figure 1 A hydraulic schematic diagram of a tensioning hydraulic system that exists independently in the prior art;

[0034] Figure 2 This is a structural schematic diagram of a tracked hydraulic system according to a specific embodiment of this application;

[0035] Figure 3 A hydraulic schematic diagram of a tracked hydraulic system according to a specific embodiment of this application;

[0036] Figure 4 , Figure 5 They are respectively Figure 3 The structural principle diagram of the walking balance valve and tension valve assembly.

[0037] Explanation of reference numerals in the attached figures

[0038] 1. Engine 2. Main Pump

[0039] 3 Return oil filter 4 Suction oil filter

[0040] 5. Oil drain filter 6. Pump oil check valve

[0041] 7 Main valve 8 Accumulator

[0042] 9. Tensioning valve assembly 10. Tensioning cylinder

[0043] 11 First check valve 12 Pressure reducing valve

[0044] 13 Second check valve 14 Oil relief valve

[0045] 15 Adjustable flow valve 16 Pressure test connector

[0046] 17 Pressure sensor 18 Walking motor

[0047] 19 Walking balance valve 20 Pressure holding relief valve

[0048] 21 Hydraulic directional valve 22 Idler wheel Detailed Implementation

[0049] The specific embodiments of this application will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are for illustration and explanation only and are not intended to limit this application. It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other.

[0050] The tracked hydraulic system and hydraulic excavator of this application will now be described in detail with reference to the accompanying drawings and embodiments.

[0051] This application discloses a novel track hydraulic system. For example... Figure 2 , Figure 3 As shown, in one specific embodiment, the novel track hydraulic system includes:

[0052] The travel hydraulic circuit includes a travel motor 18, a main valve 7, and a travel balance valve 19. The travel balance valve 19 is installed in the motor working oil circuit between the travel motor 18 and the main valve 7.

[0053] The tensioning hydraulic circuit includes a tensioning cylinder 10 for tensioning the track and a tensioning valve assembly 9 for controlling the tensioning cylinder 10.

[0054] The tensioning hydraulic circuit is bypassed and connected to the motor working oil circuit between the walking balance valve 19 and the main valve 7.

[0055] It is evident that, unlike Figure 1 In the prior art shown, a separate hydraulic pump is used to supply oil to the tensioning system. This application bypasses the tensioning hydraulic circuit and connects it to the travel hydraulic circuit. The tensioning cylinder 10 is tensioned by introducing oil into the travel motor 18, thus eliminating the need for a separate hydraulic pump to supply oil to the entire tensioning hydraulic circuit. This simplifies the hydraulic system and reduces energy consumption. The oil output from the main valve 7 enters the tensioning valve assembly 9 simultaneously with the travel balance valve 19. Based on this design, as will be explained below, an integrated valve assembly design can also be achieved, further increasing the integration while reducing hydraulic components such as the hydraulic pump, making the system layout more convenient and concise.

[0056] After the tensioning cylinder 10 is tensioned by introducing hydraulic oil to drive the travel motor 18, the tensioning action of the tensioning cylinder 10 should take precedence over the traveling action of the travel motor 18. In other words, the tracks can only be driven to travel after they are tensioned. To this end, the travel balance valve 19 in this embodiment also includes a hydraulically controlled directional valve 21, see [link to relevant documentation]. Figure 4 The pilot control oil circuit of the hydraulic directional valve 21 is hydraulically connected to the motor working oil circuit connected to the tension valve assembly 9. In other words, the oil pressure in the tension hydraulic circuit is hydraulically fed back to the hydraulic control end of the hydraulic directional valve 21. Thus, the hydraulic directional valve 21 can only switch when the oil pressure in the tension hydraulic circuit is large enough (e.g., to achieve the expected track tensioning effect) to drive the hydraulic directional valve 21 to switch. Only then can the hydraulic oil flowing through the main valve 7 drive the travel motor 18 to operate.

[0057] This hydraulically piloted directional control valve 21 is equivalent to a hydraulically controlled on / off valve, which only activates the travel hydraulic circuit when the oil pressure in the tensioning hydraulic circuit reaches the set value. However, since the travel motor 18 can be driven in both directions, the hydraulically piloted directional control valve 21 shown in the figure can be a three-position four-way valve, but it is obviously not limited to this. By adding the hydraulically piloted directional control valve 21 inside the travel balance valve 19, it is ensured that the tensioning action takes precedence over the travel action, avoiding travel failures when the tracks are slack. Specifically, after the oil enters the travel balance valve 19, the valve core of the hydraulically piloted directional control valve 21 will not immediately switch. The oil will first enter the tensioning valve assembly 9 and then, after passing through the first check valve 11, enter the pressure reducing valve 12 for pressure reduction before entering the tensioning cylinder 10 and the accumulator 8. The pressure will continue until it reaches the set pressure of the pressure reducing valve 12, at which point the balance valve core will start to switch, and the travel motor 18 will start to operate.

[0058] See Figure 3 The tensioning hydraulic circuit in this embodiment also includes an accumulator 8, which is hydraulically connected to the pressure chamber of the tensioning cylinder 10. When the track is subjected to an impact during its movement, pressure is transmitted between the tensioning cylinder 10 and the accumulator 8, causing the tensioning cylinder 10 to retract to a certain extent, thereby appropriately loosening the track.

[0059] Hydraulic oil flows through the main valve 7, the motor working oil circuit, and the tensioning hydraulic circuit to the pressure chamber of the tensioning cylinder 10, while simultaneously pressurizing the accumulator 8. The accumulator 8 can also replenish oil and pressure to the pressure chamber of the tensioning cylinder 10. After the tensioning system pressure is established, the tensioning cylinder 10 extends the drive guide wheel 22 to tension the track. When the road surface is uneven or the track is impacted, the tensioning cylinder 10 will retract due to the impact. At this time, the buffering function of the accumulator 8 is needed to achieve a dynamic balance between the two.

[0060] Specifically, regarding tension valve assembly 9, such as Figure 5In one specific structural form shown, the tensioning valve assembly 9 includes a pressure reducing valve 12. Hydraulic oil from the motor's working oil circuit flows into the pressure chamber of the tensioning cylinder 10 after passing through the pressure reducing valve 12. This allows the piston rod of the tensioning cylinder 10 to extend and push the guide wheel 22, thereby tensioning the tracks. It can be seen that the oil entering the travel motor 18 simultaneously enters the tensioning valve assembly 9, and after being reduced to a set pressure by the pressure reducing valve 12, it enters the accumulator 8 and the tensioning cylinder 10, causing the tensioning cylinder 10 to be in the extended state, thus realizing the function of automatic track tensioning during excavator operation.

[0061] As is well known to those skilled in the art, a balancing valve generally includes a relief valve and a check valve connected in parallel. Figure 4 The walking balance valve 19 shown also includes a pressure-holding relief valve 20 and a check valve integrated into the hydraulic directional valve 21. The relief pressure setting value of the pressure-holding relief valve 20 is greater than the pressure setting value of the pressure-reducing valve 12, so as to ensure that the internal pressure of the tensioning valve assembly 9 can be built up to the pressure setting value of the pressure-reducing valve 12 under any circumstances.

[0062] In addition, the tensioning valve assembly 9 may also include a first check valve 11, which is located before the pressure reducing valve 12 and is used to prevent the oil in the tensioning hydraulic circuit from flowing back into the motor working oil circuit, thereby avoiding interference between the oil circuits.

[0063] like Figure 5 The tensioning valve assembly 9 may include an oil relief valve 14, which is hydraulically connected to the oil circuit between the pressure chamber of the tensioning cylinder 10 and the pressure reducing valve 12. If the tensioning cylinder 10 is subjected to excessive impact, exceeding the absorption limit of the accumulator 8, the hydraulic oil will overflow through the oil relief valve 14 to protect the system.

[0064] Specifically, the tensioning valve assembly 9 may also include an adjustable throttle valve 15, which is connected in parallel with the oil relief valve 14 and is used to throttle and return the oil in the pressure chamber of the tensioning cylinder 10. When maintenance or component disassembly is required, the tensioning system needs to be depressurized. At this time, simply adjust the adjustable throttle valve 15 to depressurize, and the oil will return to the oil tank. This allows for pressure relief at any time, ensuring the safety of operators.

[0065] The tensioning valve assembly 9 may also include a second check valve 13, which is located downstream of the pressure reducing valve 12 to prevent backflow of oil in the pressure chamber of the tensioning cylinder 10. During the impact process of the tensioning cylinder 10, the second check valve 13 inside the tensioning valve assembly 9 can prevent oil from flowing back into the pressure reducing valve 12 and damaging the components.

[0066] In addition, the track hydraulic system may also include:

[0067] Pressure sensor 17 is used to detect the oil pressure in the pressure chamber of tension cylinder 10;

[0068] The controller is configured as follows:

[0069] It is confirmed that the walking motor 18 is in a continuous working state, and the oil pressure detected by the pressure sensor 17 is continuously less than the set value of the pressure reducing valve 12 within a set time.

[0070] If the problem is determined to be a component failure or leak, an alarm will be triggered for repair.

[0071] Ensure that the oil pressure detected by pressure sensor 17 is not less than the set overflow value of oil relief valve 14;

[0072] Identify abnormal operating conditions and trigger an alarm for repair.

[0073] See Figure 3 The tensioning cylinder 10 is equipped with a dedicated pressure test port connected to a pressure sensor 17, which is used to continuously monitor whether the tensioning pressure value is within the normal range and determine whether to sound an alarm. The main pressure values ​​of the entire tensioning system include the set value of the pressure reducing valve 12 and the set overflow value of the oil relief valve 14, and the pressure is easy to adjust. The tensioning cylinder 10 is also equipped with a dedicated pressure test port connected to the pressure sensor 17. The pressure test connectors 16 on the tensioning valve assembly 9 facilitate observation of the pressure values ​​during adjustment. One pressure test connector 16 measures the downstream pressure of the pressure reducing valve 12, and the other pressure test connector 16 measures the residual pressure of the system after pressure relief, preventing potential hazards.

[0074] exist Figure 2 , Figure 3 The tracked hydraulic system shown can have multiple main pumps 2 and multiple main valves that can perform the same function, working together to supply hydraulic oil to the actuators. Driven by the engine 1, the main pump 2 pumps oil from the oil tank through the suction filter 4, and then pumps it to the main valve 7 through the pump check valve 6, which prevents backflow. After entering the control main valve 7, the pumped oil then enters the travel balance valve 19. Figure 4 Simultaneously, the tension valve assembly 9 (with port B1 or B2 in the middle) enters the tension valve assembly 9. Figure 5 (C1 or C2 port in the tensioning valve assembly 9) After being reduced to the set pressure by the pressure reducing valve 12 inside the tensioning valve assembly 9, simultaneously (through...) Figure 5 The energy enters the accumulator 8 through port P1 and (via...) Figure 5 The track tensioning cylinder 10 is activated by the P0 port of the hydraulic valve assembly 9. The cylinder extends, causing the track to tension. When the internal pressure of the tensioning valve assembly 9 rises to the switching pressure of the hydraulically controlled directional valve 21 in the travel balance valve 19, the hydraulically controlled directional valve 21 switches, at which point the travel motor 18 begins its travel motion. The track tensioning action precedes the travel motion to prevent travel in a slack track state.

[0075] When the track and tension cylinder 10 are subjected to significant impact during movement, and the pressure of tension cylinder 10 exceeds the set pressure of the oil relief valve 14 inside the valve group, it will automatically overflow to prevent component damage. At the same time, tension cylinder 10 has an oil port for pressure measurement, which is connected to pressure sensor 17 to detect two abnormal conditions of the entire tensioning system. When the travel motor 18 moves and the internal pressure of tension cylinder 10 is continuously less than the set value of pressure reducing valve 12, it can be judged that the component is faulty or leaking. When the internal pressure of tension cylinder 10 is greater than or equal to the set pressure of oil relief valve 14, the working condition is abnormal. When either of these abnormal conditions occurs, the controller will judge and alarm by collecting data from pressure sensor 17, reminding the operator to stop immediately for inspection and maintenance, and protect the safety of the operator. The equipped travel balance valve 19 can ensure that the excavator travels more smoothly during travel and prevent speed loss due to loss of power during travel. In addition, the hydraulic control directional valve 21 in the travel balance valve 19 can ensure that the excavator will not travel if the internal pressure of the tension valve group 9 has not reached the set value, until the pressure of the tension valve group 9 is established.

[0076] In the oil return section, the oil return from the main valve 7 in the neutral position can be returned through the oil return filter 3, and the oil return from the travel motor 18 and the adjustable throttle valve 15 in the tension valve group 9 can be returned to the oil tank through the drain filter 5.

[0077] This application also discloses a hydraulic excavator including the aforementioned track hydraulic system. The aforementioned track hydraulic system is particularly suitable for ultra-large tonnage hydraulic excavators, such as excavators with a self-weight of over 100 tons, serving as their track hydraulic tensioning system. It allows for direct control of track tensioning entirely through the hydraulic system. Before the excavator begins its traveling motion, hydraulic oil from the main pump enters the traveling balance valve and simultaneously enters the tensioning valve assembly through the main valve. Before the traveling motor actuates, hydraulic oil first enters the tensioning valve assembly to charge the accumulator. After the tensioning cylinder extends and tensions the tracks, the traveling motor then begins its traveling motion. The entire tensioning function and process requires no additional manual operation.

[0078] Furthermore, there is no need for a separate hydraulic pump to supply oil to the entire tensioning system, simplifying the hydraulic system. Additionally, it achieves a high degree of integration of hydraulic valves; pressure reducing valves, relief valves, check valves, etc., in the entire tensioning system are integrated into a single valve assembly, making the layout convenient and simple. An adjustable throttle valve is used for system pressure relief, ensuring the safety of personnel during disassembly and maintenance; pressure testing points are set in the tensioning valve assembly, facilitating real-time monitoring of the system pressure during maintenance or disassembly, improving work efficiency and ensuring operational safety; check valves are installed between the multiple main oil inlets of the tensioning valve assembly to ensure that the oil circuits are not interfered with.

[0079] In the description of this application, it should be understood that the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0080] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a connection that allows communication between components; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise expressly limited. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0081] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0082] Although embodiments of this application have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting this application. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of this application.

Claims

1. A tracked hydraulic system, characterized in that, The track hydraulic system includes: The walking hydraulic circuit includes a walking motor (18), a main valve (7) and a walking balance valve (19), wherein the walking balance valve (19) is disposed in the motor working oil circuit between the walking motor (18) and the main valve (7); The tensioning hydraulic circuit includes a tensioning cylinder (10) for tensioning the track and a tensioning valve assembly (9) for controlling the tensioning cylinder (10); The tensioning hydraulic circuit is bypassed and connected to the motor working oil circuit between the walking balance valve (19) and the main valve (7).

2. The tracked hydraulic system according to claim 1, characterized in that, The walking balance valve (19) includes: The pilot control oil circuit of the hydraulic directional valve (21) is hydraulically connected to the motor working oil circuit connected to the tension valve assembly (9).

3. The tracked hydraulic system according to claim 1, characterized in that, The tensioning hydraulic circuit includes: The accumulator (8) is hydraulically connected to the pressure chamber of the tensioning cylinder (10).

4. The tracked hydraulic system according to any one of claims 1 to 3, characterized in that, The tensioning valve assembly (9) includes: Pressure reducing valve (12): Hydraulic oil from the motor working oil circuit flows into the pressure chamber of the tensioning cylinder (10) after passing through the pressure reducing valve (12).

5. The tracked hydraulic system according to claim 4, characterized in that, The walking balance valve (19) includes a pressure holding overflow valve (20), the overflow pressure setting value of the pressure holding overflow valve (20) is greater than the pressure setting value of the pressure reducing valve (12).

6. The tracked hydraulic system according to claim 4, characterized in that, The tensioning valve assembly (9) includes: A first check valve (11) is disposed before the pressure reducing valve (12) and is used to prevent the oil in the tensioning hydraulic circuit from flowing back into the motor working oil circuit.

7. The tracked hydraulic system according to claim 6, characterized in that, The tensioning valve assembly (9) includes: The oil relief valve (14) is hydraulically connected in the oil circuit between the pressure chamber of the tensioning cylinder (10) and the pressure reducing valve (12).

8. The tracked hydraulic system according to claim 7, characterized in that, The track hydraulic system includes: Pressure sensor (17) is used to detect the oil pressure in the pressure chamber of the tensioning cylinder (10); The controller is configured as follows: It is determined that the walking motor (18) is in a continuous working state, and the oil pressure detected by the pressure sensor (17) is continuously less than the set value of the pressure reducing valve (12) within a set time. If the problem is determined to be a component failure or leak, an alarm will be triggered for repair. The oil pressure detected by the pressure sensor (17) is not less than the set overflow value of the oil relief valve (14); Identify abnormal operating conditions and trigger an alarm for repair.

9. The tracked hydraulic system according to claim 7, characterized in that, The tensioning valve assembly (9) includes: An adjustable throttle valve (15) is connected in parallel with the drain relief valve (14) and is used to throttle the return oil in the pressure chamber of the tensioning cylinder (10); and / or A second check valve (13) is provided after the pressure reducing valve (12) to prevent the backflow of oil in the pressure chamber of the tensioning cylinder (10).

10. A hydraulic excavator, characterized in that, The hydraulic excavator includes a tracked hydraulic system according to any one of claims 1 to 9.

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