Oil replenishment system for hydrostatically engineered machine closed walking system

Abstract

The application discloses a supplement oil system for a closed walking system of a hydrostatic engineering machine, comprising an oil tank, a supplement oil pump, a one-way valve, a closed walking system pipeline, an overflow valve, an oil return valve block and an oil cooler which are sequentially connected through pipelines, wherein the oil cooler is connected to the oil tank through an oil return pipeline, wherein an external constant-pressure oil source is further connected through a first pipeline between the one-way valve and the closed walking system pipeline, wherein the closed walking system pipeline is provided with a variable pump and a variable motor which are connected to the oil return valve block, and the position of the oil return valve block is higher than those of the variable pump and the variable motor. The supplement oil system for the closed walking system of the hydrostatic engineering machine can solve the problem of air bubbles generated during oil supplement, complete oil supplement and air discharge at the same time, and improve work efficiency.

Description

Technical Field

[0001] This utility model relates to the field of oil replenishment system technology, and in particular to an oil replenishment system for closed-loop travel systems of hydrostatic engineering machinery. Background Technology

[0002] Hydrostatic engineering machinery (such as bulldozers) typically employs a closed-loop hydraulic system for its travel system. Its main core components include a variable displacement pump, a variable displacement motor, and connecting pipes between the oil inlets. When starting the engine for the first time after the entire hydrostatic bulldozer is assembled, hydraulic fluid needs to be added to the hydraulic tank. After adding fluid, the engine needs to be started and stopped several times (running briefly and then shut off) to bleed the hydraulic system piping. Simultaneously, before adding oil to the tank, the variable displacement pump and motor housings need to be lubricated to prevent mechanical friction damage to these components due to insufficient lubrication during the initial start, which could lead to malfunctions of the variable displacement pump and motor.

[0003] In existing technologies, pneumatic fuel dispensers are commonly used to fill hydraulic oil tanks, with the fuel nozzle placed at the filler neck. Because the oil falls freely from the nozzle into the tank, it is prone to splashing, generating numerous air bubbles that enter the oil. These air bubbles may not dissipate for extended periods or may even enter the system with the oil, leading to cavitation and cavitation phenomena that damage components and shorten their lifespan. Utility Model Content

[0004] This application provides an oil replenishment system for a closed-loop walking system of hydrostatic engineering machinery, which can solve the problem of air bubbles generated during the refueling process, and simultaneously complete oil filling and air venting, thereby improving work efficiency.

[0005] This application provides an oil replenishment system for a closed-loop travel system of hydrostatic engineering machinery, comprising an oil tank, an oil replenishment pump, a check valve, a closed-loop travel system pipeline, an overflow valve, a return valve block, and an oil cooler connected in sequence via pipelines. The oil cooler is connected to the oil tank via a return pipeline. An external constant pressure oil source is connected between the check valve and the closed-loop travel system pipeline via a first pipeline. The closed-loop travel system pipeline is equipped with a variable pump and a variable motor that are simultaneously connected to the return valve block, and the position of the return valve block is higher than the positions of the variable pump and the variable motor.

[0006] In one possible implementation, the end of the first pipeline is provided with a first quick-connect fitting, and the external constant pressure oil source is connected to a second quick-connect fitting suitable for inserting the first quick-connect fitting.

[0007] In one possible implementation, an oil replenishment filter is also connected between the replenishment pump and the closed-loop travel system pipeline.

[0008] In one possible implementation, the replenishing filter is located upstream or downstream of the one-way valve.

[0009] In one possible implementation, the overflow valves are integrated on the variable pump and the variable motor, respectively, wherein the overflow valve integrated on the variable pump is a variable pump overflow valve, and the overflow valve integrated on the variable motor is a variable motor overflow valve.

[0010] In one possible implementation, the closed-loop travel system pipeline includes a left-side travel system pipeline and a right-side travel system pipeline, and the variable pump and the variable motor are symmetrically arranged in the left-side travel system pipeline and the right-side travel system pipeline, wherein the variable pump and the variable motor in the left-side travel system pipeline are respectively a first variable pump and a first variable motor, and wherein the variable pump and the variable motor in the right-side travel system pipeline are respectively a second variable pump and a second variable motor. The first pipeline is connected to the first variable pump and the second variable pump through a first branch and a second branch, respectively. The first variable pump and the second variable pump are connected to the return oil valve block through a second pipeline, respectively. The return oil valve block is connected to the first variable motor and the second variable motor, respectively.

[0011] In one possible implementation, the variable pump relief valve is a replenishing relief valve, and the variable motor relief valve is a flushing relief valve.

[0012] Beneficial effects: Compared with the prior art, the oil replenishment system for the closed-loop travel system of hydrostatic engineering machinery provided in this application, by setting up an oil tank, oil replenishment pump, check valve, closed-loop travel system pipeline, relief valve, return valve block and oil cooler connected in sequence, the added hydraulic oil will fill the closed-loop travel system pipeline and the internal oil passages of the variable pump and variable motor. Under the action of the relief valve, the oil and air will be carried out into the housing of the variable pump and variable motor, and then flow back to the oil tank together with the oil through the return valve block and oil cooler. The oil filling process and the air venting process are completed at the same time, thereby saving the process of inching air venting and the process of pre-filling the housing of the variable pump and variable motor, which can significantly improve the work efficiency.

[0013] These and other objects, features and advantages of this utility model will be fully realized through the following detailed description. Attached Figure Description

[0014] Figure 1 A schematic diagram of the oil replenishment system for the closed-loop travel system of hydrostatic engineering machinery is shown. Detailed Implementation

[0015] The following description is intended to disclose the present invention so that those skilled in the art can implement it. The preferred embodiments described below are merely examples, and other obvious variations will occur to those skilled in the art. The basic principles of the present invention defined in the following description can be applied to other embodiments, modifications, improvements, equivalents, and other technical solutions that do not depart from the spirit and scope of the present invention.

[0016] Those skilled in the art should understand that, in the disclosure of this specification, the terms "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, the above terms should not be construed as limitations on this utility model.

[0017] It is understood that the term "a" should be understood as "at least one" or "one or more", that is, in one embodiment, the number of an element can be one, while in another embodiment, the number of the element can be multiple, and the term "a" should not be understood as a limitation on the number.

[0018] refer to Figure 1 This application provides an oil replenishment system for a closed-loop travel system of hydrostatic engineering machinery, including an oil tank 10, an oil replenishment pump 20, a check valve 30, a closed-loop travel system pipeline, an overflow valve 40, a return valve block 50, and an oil cooler 60 connected in sequence by pipelines. The oil cooler 60 is connected to the oil tank 10 through a return pipeline. An external constant pressure oil source 70 is connected between the check valve 30 and the closed-loop travel system pipeline through a first pipeline 31 to provide hydraulic oil. The closed-loop travel system pipeline is equipped with a variable pump 80 and a variable motor 90 connected to the return valve block 50, and the position of the return valve block 50 is higher than the positions of the variable pump 80 and the variable motor 90.

[0019] The working principle is as follows: After the vehicle assembly is completed, the external constant pressure oil source 70 (whose pressure is greater than the relief valve's set pressure) is connected to the oil replenishment system via pipeline for pressure oil injection. Because the oil replenishment system is equipped with a check valve 30, the injected hydraulic oil enters the closed-loop travel system pipeline through the replenishment pipeline. When the oil fills the closed-loop travel system pipeline, as well as the internal oil passages and piston chambers of the variable pump 80 and variable motor 90, the pressure of the injected oil will build up due to the presence of the check valve 30, reaching the pressure of the external constant pressure oil source 70. Since the pressure of the external constant pressure oil source 70 is greater than the set pressure of the relief valve 40... When the overflow valve 40 opens, it carries the oil and internal air into the housings of the variable pump 80 and variable motor 90. At the same time, the position of the return valve block 50 is higher than that of the variable pump 80 and variable motor 90. The internal air rises into the return valve block 50 and flows back into the oil tank 10 along with the oil through the return pipeline via the return valve block 50 and the oil cooler 60. This completes the oil filling process and the air venting process, thereby saving the process of inching air venting and the process of pre-filling the variable pump housing and variable motor housing with oil, thus greatly improving work efficiency.

[0020] In one embodiment, the end of the first pipeline 31 is provided with a first quick-connect connector 311, and the external constant pressure oil source 70 is connected to a second quick-connect connector 71 suitable for plugging into the first quick-connect connector 311. After the hydraulic oil is added and the machine is started, the second quick-connect connector 71 needs to be disconnected to disconnect the external constant pressure oil source 70. The oil replenishment pump 20 pumps hydraulic oil into the closed-loop travel system for replenishment. Therefore, the use of quick-connect connectors facilitates plugging and unplugging operations, allowing for immediate plugging and unplugging and saving time.

[0021] The one-way valve 30 plays a role in preventing pressure surges in the oil replenishment system from damaging the oil replenishment pump 20 during the oil replenishment process.

[0022] In one embodiment, an oil replenishment filter 21 is also connected between the replenishment pump 20 and the closed-loop travel system pipeline, so that the hydraulic oil is filtered before entering the closed-loop travel system pipeline, thereby filtering the hydraulic oil, improving the cleanliness of the oil, and reducing component failures that may be caused by unqualified external oil cleanliness.

[0023] In one embodiment, the replenishing filter 21 is located upstream or downstream of the one-way valve 30, wherein the replenishing filter 21 is preferably located downstream of the one-way valve 30. The one-way valve 30 prevents oil from leaking from the replenishing pump 20 into the oil tank 10, thus preventing pressure from building up during external refueling and ensuring that the overflow valve 40 does not reach the overflow state.

[0024] In one embodiment, the overflow valve 40 is integrated on the variable pump 80 and the variable motor 90 respectively. The overflow valve 40 integrated on the variable pump 80 is a variable pump overflow valve, and the overflow valve 40 integrated on the variable motor 90 is a variable motor overflow valve, which makes the system more integrated, simpler and more compact in structure, and easier to maintain.

[0025] In one embodiment, the closed-loop travel system pipeline includes a left-side travel system pipeline and a right-side travel system pipeline. The variable pump 80 and the variable motor 90 are symmetrically arranged in the left-side travel system pipeline and the right-side travel system pipeline, wherein the variable pump 80 and the variable motor 90 in the left-side travel system pipeline are respectively a first variable pump 81 and a first variable motor 91, and the variable pump 80 and the variable motor 90 in the right-side travel system pipeline are respectively a second variable pump 82 and a second variable motor 92. The first pipeline 31 is connected to the first variable pump 81 and the second variable pump 82 through the first branch 311 and the second branch 312 respectively. At the same time, the first variable pump 81 and the second variable pump 82 are connected to the return oil valve block 50 through the second pipeline respectively. The return oil valve block 50 is connected to the first variable motor 91 and the second variable motor 92 respectively. Thus, the oil filling and air venting of the closed travel system on both sides of the construction machinery can be completed simultaneously.

[0026] Specifically, an external constant-pressure oil source 70 provides constant-pressure hydraulic oil with a pressure greater than that of the relief valve 40. Under the action of the check valve 30, the oil enters the closed-loop travel system pipeline through the first pipeline 31 and the replenishing oil filter 21. Subsequently, it enters the first variable pump 81 and the second variable pump 82 through the first branch 311 and the second branch 312, respectively. Through the internal oil passage of the variable pump 80, it enters the high-pressure pipeline (including the plunger orifice pipeline) of the variable pump via the replenishing oil check valve 83. When the pipeline is filled with oil, the oil pressure gradually builds up. After the oil pressure exceeds the pressure of the variable pump relief valve, it enters the pump housing 84 of the first variable pump 81 and the second variable pump 82, respectively. At the same time, the air in the high-pressure pipeline will be carried by the oil. The hydraulic fluid enters the pump housing 84 and then flows through pipelines to the return valve block 50. Since both the variable pump 80 and the variable motor 90 are connected to the return valve block 50, and the return valve block 50 is positioned higher than the variable pump 80 and variable motor 90, the hydraulic fluid in the return valve block 50 flows back to the high-pressure pipelines of the first variable motor 91 and the second variable motor 92. After pressure is established, the fluid flows through the variable motor relief valves to the motor housings 93 of the first and second variable motors, respectively. Air inside the pump housing 84 and the motor housing 93 is driven to the return valve block 50 by the hydraulic fluid, then flows back to the oil tank 10 via the oil cooler 60, and finally is discharged to the outside through the breather. The refueling process stops when the hydraulic fluid reaches the middle position of the oil tank level gauge, completing the refueling process. The entire machine can then be started directly, eliminating the need for inching for venting and pre-filling the housings of the variable pump 80 and variable motor 90, thus significantly improving work efficiency.

[0027] In one embodiment, the variable pump relief valve is a replenishing relief valve, which integrates both a replenishing valve and a relief valve. It allows oil to flow unidirectionally from the replenishing pipeline (or oil tank) into the low-pressure side of the system to replenish the oil, while simultaneously draining excess oil from the low-pressure side of the system back into the oil tank to limit the maximum pressure on the low-pressure side.

[0028] The variable displacement motor relief valve is a flushing relief valve. The flushing relief valve is a key component and specific manifestation of the function of the replenishing relief valve. It not only functions as a relief valve, but also achieves system cooling and purification by continuously replacing hot oil with cold oil in a closed hydraulic system.

[0029] It should be noted that the terms "first" and "second" used in this application are for descriptive purposes only and do not indicate any order. They should not be construed as indicating or implying relative importance, and can be interpreted as names.

[0030] Those skilled in the art should understand that the embodiments of the present invention described above and shown in the accompanying drawings are merely examples and do not limit the present invention. The advantages of the present invention have been fully and effectively realized. The functions and structural principles of the present invention have been shown and explained in the embodiments, and any modifications or variations may be made to the implementation of the present invention without departing from the stated principles.

Claims

1. A replenishing system for a hydrostatically powered engineering vehicle closed walking system, characterized in that The system includes an oil tank, a replenishing pump, a check valve, a closed-loop travel system pipeline, an overflow valve, a return valve block, and an oil cooler, all connected sequentially via pipelines. The oil cooler is connected to the oil tank via a return pipeline. An external constant-pressure oil source is connected between the check valve and the closed-loop travel system pipeline via a first pipeline. The closed-loop travel system pipeline is equipped with a variable pump and a variable motor, both connected to the return valve block, and the return valve block is positioned higher than both the variable pump and the variable motor.

2. The oil replenishment system for a closed-loop travel system of hydrostatic engineering machinery as described in claim 1, characterized in that, The first pipeline is provided with a first quick-connect fitting at its end, and the external constant pressure oil source is connected to a second quick-connect fitting suitable for inserting the first quick-connect fitting.

3. The oil replenishment system for a closed-loop travel system of hydrostatic engineering machinery as described in claim 1, characterized in that, An oil replenishment filter is connected between the oil replenishment pump and the closed-loop travel system pipeline.

4. The oil replenishment system for a closed-loop travel system of hydrostatic engineering machinery as described in claim 3, characterized in that, The oil replenishment filter is located upstream or downstream of the one-way valve.

5. The oil replenishment system for a closed-loop travel system of hydrostatic engineering machinery as described in claim 3, characterized in that, The overflow valves are respectively integrated on the variable pump and the variable motor, wherein the overflow valve integrated on the variable pump is a variable pump overflow valve, and the overflow valve integrated on the variable motor is a variable motor overflow valve.

6. The oil replenishment system for a closed-loop travel system of hydrostatic engineering machinery as described in claim 5, characterized in that, The closed-loop travel system pipeline includes a left-side travel system pipeline and a right-side travel system pipeline. The variable pump and the variable motor are symmetrically arranged in the left-side travel system pipeline and the right-side travel system pipeline. The variable pump and the variable motor in the left-side travel system pipeline are respectively a first variable pump and a first variable motor. The variable pump and the variable motor in the right-side travel system pipeline are respectively a second variable pump and a second variable motor. The first pipeline is connected to the first variable pump and the second variable pump through a first branch and a second branch, respectively. The first variable pump and the second variable pump are connected to the return oil valve block through a second pipeline, respectively. The return oil valve block is connected to the first variable motor and the second variable motor, respectively.

7. The oil replenishment system for a closed-loop travel system of hydrostatic engineering machinery as described in claim 5, characterized in that, The variable pump relief valve is a replenishing relief valve, and the variable motor relief valve is a flushing relief valve.

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