High-low pressure switching valve, pumping control valve group, and pumping hydraulic system

Abstract

The application belongs to the field of pumping control, and discloses a high-low pressure switching valve, a pumping control valve group and a pumping hydraulic system. The high-low pressure switching valve comprises a switching valve body and a switching valve rod, an axial switching valve rod cavity is arranged in the switching valve body, a plurality of first side oil ports, a plurality of second side oil ports and a compensation oil cavity are arranged on the valve wall of the switching valve body and extend to the switching valve rod cavity respectively, and the plurality of second side oil ports comprise a rod cavity connecting oil port group and a non-rod cavity oil port group; the switching valve rod is slidably arranged in the switching valve rod cavity and is used for controlling the plurality of first side oil ports to selectively communicate with the rod cavity connecting oil port group or the non-rod cavity oil port group according to the valve rod moving stroke, and a valve rod compensation oil flow channel for communicating the compensation oil cavity with the second side oil ports is arranged in the switching valve rod. The high-low pressure switching valve of the application can realize the high-low pressure pumping mode with simple structure and low cost, improve the working condition adaptability, and can integrate the compensation oil function without external pipeline.

Description

Technical Field

[0001] This application belongs to the field of pumping control, specifically, it relates to a high-low pressure switching valve, a pumping control valve group, and a pumping hydraulic system. Background Technology

[0002] When hydraulically driving a pump cylinder assembly, if high-pressure oil is connected to the rod chamber, it is in low-pressure drive mode, and the rodless chambers are interconnected as passive chambers. Conversely, if high-pressure oil is connected to the rodless chamber, it is in high-pressure drive mode, and the rod chambers are interconnected as passive chambers. Therefore, the pump control valve assembly should generally include a high-low pressure switching valve to improve adaptability to operating conditions.

[0003] In existing technologies, separate valve group structures are designed to achieve high and low pressure switching. For example, Chinese patent application CN210461217U uses a combination of a two-position six-way spool valve and a cartridge valve to achieve high and low pressure switching. The two-position six-way spool valve is responsible for the oil chamber connection function in one state. When it is necessary to operate in a high-pressure or low-pressure state, the oil chambers (rod chamber or rodless chamber) of the two cylinders can be directly connected through the two-position six-way spool valve. However, the two-position six-way valve and two logic valves to achieve two pumping modes of high and low pressure are structurally complex, difficult to manufacture, and costly.

[0004] In addition, oil leakage is unavoidable during long-term operation or rest, resulting in a shorter cylinder stroke. Therefore, it is necessary to control oil replenishment or drainage. In this case, oil replenishment and drainage require external pipelines, valves are scattered, and the system pipeline connection cost is increased. Summary of the Invention

[0005] To address the aforementioned deficiencies or shortcomings, this application discloses a high-low pressure switching valve, a pumping control valve assembly, and a pumping hydraulic system, which achieve high-low pressure pumping and oil replenishment / unloading functions with a simple structure and low cost, thereby improving adaptability to operating conditions.

[0006] To achieve the above objectives, according to a first aspect of this application, a high-low pressure switching valve is disclosed for high-low pressure switching control of a pumping cylinder assembly, the high-low pressure switching valve comprising:

[0007] The switching valve body has an axially oriented switching valve stem cavity inside. The valve wall of the switching valve body is provided with a plurality of first side oil ports and a plurality of second side oil ports extending to the switching valve stem cavity. The plurality of second side oil ports include a rod cavity connection oil port group for connecting to the rod cavity of the pumping cylinder group and a rodless cavity oil port group for connecting to the rodless cavity of the cylinder.

[0008] A switching valve stem is slidably disposed in the switching valve stem cavity and is used to control multiple first-side oil ports to selectively connect to the rod-side cavity connection port group or to the rodless cavity oil port group according to the valve stem travel.

[0009] The valve wall of the switching valve body is also provided with a replenishment and drainage oil chamber extending to the switching valve stem cavity, and the switching valve stem is also provided with a valve stem replenishment and drainage oil passage, which is used to connect the replenishment and drainage oil chamber with the second side oil port.

[0010] In some embodiments, in the switching valve stem chamber, a plurality of first-side oil ports are arranged axially and centrally at intervals, one of the rod-side connecting oil port group and the rodless-side oil port group is arranged at intervals between the plurality of first-side oil ports, and the other is symmetrically arranged on the axially outer side of the plurality of first-side oil ports.

[0011] Wherein, at the axial end of the switching valve stem cavity, the valve wall of the switching valve body is further provided with an end communication cavity extending to the switching valve stem cavity. The end communication cavity is used to connect each oil port in the axial outer oil port group when multiple first side oil ports are connected to the axial inner oil port group of the first side oil ports.

[0012] In some embodiments, the first side port includes a first port and a second port, the rod cavity connection port group includes a first rod cavity connection port and a second rod cavity connection port, and the rodless cavity connection port group includes a first rodless cavity connection port and a second rodless cavity connection port.

[0013] The rod cavity connecting port group is the axial outer port group. The end communication cavity is arranged at the same axial end of the switching valve stem cavity as the first rod cavity connecting port and the second rod cavity connecting port, and is in communication with the other one of the first rod cavity connecting port and the second rod cavity connecting port.

[0014] In some embodiments, the switching valve stem includes:

[0015] An inner oil port connecting groove is arranged in the center and an outer oil port connecting groove is arranged at intervals on the axial outer side of the inner oil port connecting groove.

[0016] An end-connecting groove is used to control the connection between the end-connecting cavity and the oil port in the adjacent axially outer oil port group.

[0017] In some embodiments, one end of the valve stem refill / drain oil passage extends to connect with the inner oil port connecting groove, and the other end extends axially outward to the outside of the outer oil port connecting groove and is used to connect with the refill / drain oil chamber.

[0018] In some embodiments, the refill / drainage chamber and the end communication groove are distributed at both axial ends of the switching valve stem chamber.

[0019] In some embodiments, the high-low pressure switching valve also integrates a replenishment / relief oil valve, the replenishment oil outlet of which is connected to the replenishment / relief oil chamber.

[0020] In some embodiments, the refill / release valve is integrally cast onto the switching valve body.

[0021] According to a second aspect of this application, a pumping control valve assembly is disclosed, the pumping control valve assembly including a reversing valve assembly for controlling the pumping cylinder assembly and the aforementioned high-low pressure switching valve, wherein a plurality of first side oil ports are connected to the working oil ports of the reversing valve assembly.

[0022] According to a third aspect of this application, a pumping hydraulic system is also disclosed, the pumping hydraulic system including the pumping control valve assembly described above.

[0023] In the high / low pressure switching valve, pumping control valve assembly, and pumping hydraulic system of this application, both high and low pressure pumping modes are achieved through a single valve structure. Specifically, by switching the valve stem, multiple first-side ports selectively connect to the rod-side connection port group to achieve a low-pressure pumping mode; or by switching the valve stem, multiple first-side ports selectively connect to the rodless connection port group to achieve a high-pressure pumping mode. Compared to the prior art that uses multiple valves to achieve high / low pressure pumping switching modes, this significantly simplifies the product structure, increases integration, and reduces processing difficulty and cost. Furthermore, it can integrate a replenishment / relief oil chamber, and the switching valve stem also has a valve stem replenishment / relief oil passage to connect the replenishment / relief oil chamber to the second-side port. The replenishment / relief oil chamber can be connected to the low-pressure side of the rod-side or rodless side of the cylinder through the second-side port to supply oil to the pumping cylinder as needed or for oil return from the cylinder. By integrating the replenishment / relief oil function, the product integration level can be improved, and the system piping connection cost can be reduced.

[0024] Other features and advantages of this application will be described in detail in the following detailed description section. Attached Figure Description

[0025] 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:

[0026] Figure 1 This is a schematic diagram of the reversing valve assembly according to a specific embodiment of this application;

[0027] Figure 2 for Figure 1 A schematic diagram of the reversing valve body in the reversing valve assembly is shown.

[0028] Figure 3 for Figure 1 A schematic diagram of the reversing valve stem in the reversing valve assembly is shown.

[0029] Figure 4 This is a schematic diagram of the high-low pressure switching valve according to a specific embodiment of this application;

[0030] Figure 5 for Figure 4 The diagram shows the structure of the switching valve body in the high-low pressure switching valve.

[0031] Figure 6 for Figure 4 The diagram shows the structure of the switching valve stem in the high-low pressure switching valve.

[0032] Figure 7 This is a hydraulic schematic diagram of a pumping hydraulic system according to a specific embodiment of this application.

[0033] Explanation of reference numerals in the attached figures

[0034] Detailed Implementation

[0035] 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 the scope of this application.

[0036] The following description, with reference to the accompanying drawings, describes the directional valve assembly and pumping hydraulic system according to this application.

[0037] This application discloses a novel high-low pressure switching valve for high-low pressure switching control of a pumping cylinder assembly. For example... Figures 4 to 6 As shown, a high-low pressure switching valve 400 in one specific embodiment includes:

[0038] The switching valve body 4 has an axially oriented switching valve stem cavity 5 inside. The valve wall of the switching valve body 4 is provided with a plurality of first side oil ports and a plurality of second side oil ports extending to the switching valve stem cavity 5. The plurality of second side oil ports include a rod cavity connection oil port group for connecting to the rod cavity of the pumping cylinder group and a rodless cavity oil port group for connecting to the rodless cavity of the cylinder.

[0039] The switching valve stem 6 is slidably disposed in the switching valve stem cavity 5 and is used to control multiple first-side oil ports to selectively connect to the rod-side cavity connection port group or to the rodless cavity connection port group according to the valve stem travel.

[0040] During operation or at rest, oil leakage may occur in the pumping cylinder assembly, leading to a shortened cylinder stroke. To address this, the high / low pressure switching valve 400 in this embodiment may further integrate a replenishment / relief oil chamber 7 to supply oil to the pumping cylinder as needed or for oil return from the cylinder. See also... Figure 5 The valve wall of the switching valve body 4 is also provided with a refill / relief oil chamber 7 extending to the switching valve stem chamber 5; see also Figure 6 The switching valve stem 6 also includes a valve stem refill / relief oil passage 64, which connects the refill / relief oil chamber 7 to the second side oil port. The refill / relief oil chamber 7 can be connected to the low-pressure side of either the rod-side or rodless-side chamber of the cylinder via the second side oil port. Integrating the refill / relief oil function improves product integration and reduces system piping connection costs.

[0041] Since the replenishment / relief oil chamber 7 needs to be connected to the low-pressure side of the cylinder oil chamber for convenient oil replenishment or pressure relief, as mentioned above, when the switching valve stem 6 moves to the left valve position, the rod chambers of the two cylinders in the pumping cylinder assembly are connected, and the pumping mode is in progress. At this time, the replenishment / relief oil chamber 7 should be connected to the first rodless chamber connection port A2 and the second rodless chamber connection port B2. Similarly, when the switching valve stem 6 moves to the right valve position, the replenishment / relief oil chamber 7 should be connected to the first rod chamber connection port A1 and the second rod chamber connection port B1.

[0042] Therefore, in Figure 6 The switching valve stem 6 is provided with a valve stem refill / drainage oil passage 64. One end of the valve stem refill / drainage oil passage 64 is connected to the inner oil port connecting groove 61, and the other end is located outside the outer oil port connecting groove 62 to connect to the refill / drainage oil chamber 7. In other words, one end of the valve stem refill / drainage oil passage 64 extends to connect to the inner oil port connecting groove 61, and the other end extends axially outward to the outer side of the outer oil port connecting groove 62 and is used to connect to the refill / drainage oil chamber 7.

[0043] In this embodiment, the oil filling and draining chamber 7 and the end connecting groove C can be distributed at both ends of the switching valve stem chamber 5 along the axial direction, so that the valve body structure can be designed to be smaller and more compact.

[0044] This application discloses a novel high-low pressure switching valve that achieves both high and low pressure pumping modes through a single valve body structure. Specifically, by switching the valve stem 6, multiple first-side oil ports selectively connect to the rod-side connection port group, achieving a low-pressure pumping mode; similarly, by switching the valve stem 6, multiple first-side oil ports selectively connect to the rodless connection port group, achieving a high-pressure pumping mode. This significantly simplifies the product structure compared to existing technologies that use multiple valve components to achieve high-low pressure pumping switching, resulting in higher integration and reduced processing difficulty and cost. Furthermore, it integrates a replenishment / drainage oil chamber, and the switching valve stem also features a valve stem replenishment / drainage oil channel connecting the replenishment / drainage oil chamber to the second-side oil port. The replenishment / drainage oil chamber can be connected to the low-pressure side of the rod-side or rodless side of the cylinder via the second-side oil port, to supply oil to the pumping cylinder as needed or for oil return from the cylinder. Integrating the replenishment / drainage oil function improves product integration and reduces system piping connection costs.

[0045] To enable switching between high and low pressure pumping modes on a single valve body, see [link / reference]. Figure 5In the switching valve stem chamber 5 shown, multiple first-side oil ports are arranged axially at intervals in the center. One of the rod chamber connecting oil port group and the rodless chamber oil port group is arranged at intervals between the multiple first-side oil ports, and the other is symmetrically arranged on the axial outer side of the multiple first-side oil ports.

[0046] Among them, at the axial end of the switching valve stem cavity 5, the valve wall of the switching valve body 4 is also provided with an end communication cavity C extending to the switching valve stem cavity 5. The end communication cavity C is used to connect each oil port in the axial outer oil port group when multiple first side oil ports are connected to the axial inner oil port group of the first side oil ports.

[0047] It should be noted that the directional terms "inner" and "outer" here refer to... Figure 5 The center of the switching valve stem chamber 5 shown is used as a reference. In this embodiment, multiple first-side oil ports (including...) are first connected... Figure 5 The first oil port A' and the second oil port B' shown in the diagram are arranged at an interval in the middle. Based on this, the rodless cavity oil port group (including the first rodless cavity connecting oil port A2 and the second rodless cavity connecting oil port B2) is arranged at intervals between multiple first side oil ports, located inside the first side oil ports. The rod cavity connecting oil port group (including the first rod cavity connecting oil port A1 and the second rod cavity connecting oil port B1) is arranged at intervals outside the first side oil ports. Thus, by switching the valve stem 6 to connect the first side oil port to the rodless cavity oil port group, the oil ports of the rod cavity connecting oil port group are interconnected, thereby connecting the rod cavities of the two cylinders in the pumping cylinder group. Similarly, by switching the valve stem 6 to connect the first side oil port to the rod cavity oil port group, the oil ports of the rodless cavity connecting oil port group are interconnected, thereby connecting the rodless cavities of the two cylinders in the pumping cylinder group. Of course, the distribution of the oil ports in this application is not limited to... Figure 5 As shown, for example, the rodless cavity connecting port group can be located outside the first side port, while the rod cavity connecting port group can be located inside the first side port.

[0048] As described above, when the valve position is switched by moving the switching valve stem 6, so that the first side oil port is connected to the rod-side cavity connecting oil port group or the rodless cavity oil port group located inside the first side oil port, the oil ports in the rodless cavity connecting oil port group or the rod-side cavity oil port group located outside the first side oil port need to be connected, but... Figure 5 The port distribution shown is clearly difficult to achieve using either a connecting groove design on the switching valve stem 6 or a hollow connecting cavity design, resulting in a complex structure. Therefore, an end connecting cavity C is added. End connecting cavity C is used to connect each port in the axially outer port group when multiple first-side ports are connected to the axially inner port group of the first-side ports. In other words, end connecting cavity C is used to connect each port outside the first-side ports. For example, Figure 5The end connecting cavity C shown is an extension connecting cavity of the second rod chamber connecting port B1. It is located close to the first rod chamber connecting port A1 so that the second rod chamber connecting port B1 can communicate with the first rod chamber connecting port A1 through the end connecting cavity C when the movement position of the switching valve stem 6 is small.

[0049] In this embodiment, as an example, the high-low pressure switching valve has 6 oil ports, namely, the first side oil port includes the first oil port A' and the second oil port B', the rod chamber connection oil port group includes the first rod chamber connection oil port A1 and the second rod chamber connection oil port B1, and the rodless chamber connection oil port group includes the first rodless chamber connection oil port A2 and the second rodless chamber connection oil port B2; wherein, the rod chamber connection oil port group is an axially outer oil port group, and the end connecting cavity C is arranged at the same axial end of the switching valve rod cavity 5 with one of the first rod chamber connection oil ports A1 and the second rod chamber connection oil port B1 at intervals, and is in communication with the other of the first rod chamber connection oil ports A1 and the second rod chamber connection oil port B1.

[0050] Based on the above distribution of oil ports, see the corresponding information. Figure 6 The switching valve stem 6 may also include:

[0051] The inner oil port connecting groove 61 is arranged in the center and the outer oil port connecting groove 62 is arranged at intervals on the outer side of the inner oil port connecting groove 61.

[0052] The end connecting groove 63 is used to control the connection between the end connecting cavity C and the oil port in the adjacent axial outer oil port group.

[0053] See Figure 4 , Figure 7 When the switching valve stem 6 moves to the left valve position, the first oil port A' connects to the first rod chamber connection port A1 through the outer oil port connecting groove 62 at the left end, and the second oil port B' connects to the second rod chamber connection port B1 through the outer oil port connecting groove 62 at the right end; simultaneously, the first rodless chamber connection port A2 and the second rodless chamber connection port B2 connect through the inner oil port connecting groove 61. See [reference needed] Figure 7 At this time, the rod chambers of the two cylinders in the pumping cylinder assembly are connected, and the pumping mode is in low-pressure pumping mode.

[0054] When the switching valve stem 6 moves to the right valve position, at this time, through the outer oil port connecting groove 62 on the left end, the first oil port A' connects to the first rodless chamber connecting oil port A2, and through the inner oil port connecting groove 61, the second oil port B' connects to the second rodless chamber connecting oil port B2. The first rod chamber connecting oil port A1 and the second rod chamber connecting oil port B1 are also connected. (See also...) Figure 7 At this time, the rodless chambers of the two cylinders of the pumping cylinder group are connected, and it is in high-pressure pumping mode.

[0055] After the oil filling and draining chamber 7 is provided, an external oil filling and draining control valve can be connected. In this embodiment, the high-low pressure switching valve 400 also integrates an oil filling and draining valve 500, and the oil filling outlet of the oil filling and draining valve 500 is connected to the oil filling and draining chamber 7. In this way, the high-low pressure switching valve can not only realize the high-low pressure pumping switching function, but also has the function of oil filling and draining. Compared with the method of external oil filling control valve, which requires external pipeline and has low integration, the high-low pressure switching valve of this application does not require external pipeline and does not increase the system pipeline connection cost. In actual manufacturing, the high-low pressure switching valve can be integrally cast, that is, the oil filling and draining valve 500 can be integrally cast onto the switching valve body 4.

[0056] Those skilled in the art will understand that the oil replenishment / drainage function primarily controls the stroke of the pumping cylinder. A piston stroke detection element can be installed in the pumping cylinder assembly. When insufficient cylinder stroke is detected in the pumping cylinder assembly, see [link to relevant documentation]. Figure 7 The end electromagnet DT4 of the control valve 500 is energized to inject oil into the oil filling chamber 7 and its cylinder connecting chamber, thereby increasing the stroke of the pumping cylinder. When the cylinder stroke is detected to be too long, the end electromagnet DT3 is energized to depressurize the cylinder connecting chamber of the oil filling chamber 7, causing the oil in the cylinder chamber to return, and shortening the stroke of the pumping cylinder.

[0057] This application also discloses a pumping control valve assembly, including a reversing valve assembly (see below) for controlling a pumping cylinder assembly and a high-low pressure switching valve, wherein multiple first-side oil ports of the high-low pressure switching valve are connected to the working oil ports of the reversing valve assembly. See Figure 7 That is, the first oil port A' is connected to the second working oil chamber A, and the second oil port B' is connected to the first working oil chamber B. This pumping control valve group has a high degree of integration, a simple valve body structure, and small hydraulic shock during reversing control. It can realize both high and low pressure pumping modes, and integrates a replenishing and draining oil valve. By controlling the connection between the working oil port and the replenishing and draining oil chamber, it can control the switching between high and low pressure modes, while also performing the function of replenishing and draining oil.

[0058] Accordingly, this application also discloses a pumping hydraulic system, including a pumping control valve assembly according to this application. With this highly integrated pumping control valve assembly, only two basic valve assemblies are needed between the pumping cylinder assembly and the oil pump or the main oil circuit of the system. Moreover, the control function is comprehensive, the control operation is smooth, and the cost is low.

[0059] In addition, this application also discloses a novel directional valve assembly. See [link to application]. Figures 1 to 3 In one specific embodiment, the reversing valve group includes an integrated reversing valve 100 and an unloading valve 200. The reversing valve 100 is a spool valve and the reversing valve stem 1 is used to control the unloading valve 200 to switch to the unloading closed state at the end of the stem stroke position and to switch to the unloading open state at the midpoint of the stem stroke position.

[0060] This application aims to integrate the unloading valve 200 into the directional valve 100, using the stroke of the directional valve stem 1 to control the opening or closing of the unloading valve 200, thereby avoiding pressure surges. When the directional valve stem 1 is at the midpoint of its stroke, the unloading valve 200 is controlled to be in the unloading open state, i.e., the hydraulic control chamber of the unloading valve 200 returns oil. At this time, the high-pressure oil at port P will be unloaded at a large flow rate through the unloading valve 200. Before the directional valve stem 1 moves to the working position (e.g., the end stroke position of the valve stem in this embodiment), the high-pressure oil at port P can be at least partially unloaded through the unloading valve 200, preventing oil blockage and pressure surges at port P. Alternatively, when the directional valve stem 1 moves to a position near the midpoint of its stroke, the unloading valve 200 switches from the unloading closed state to the unloading open state. The high-pressure oil at port P will be unloaded through the unloading valve 200, rather than being suddenly released to port T or the return oil passage. Furthermore, because the pressure release in the hydraulic control chamber of the unloading valve 200 is gradual, it will not cause a sudden release of high-pressure oil from port P to port T or the return oil passage. Therefore, during pump reversal, limiting the opening speed of the unloading valve by the directional valve stem 1 can significantly reduce the instantaneous pressure impact of the main pump's high-pressure oil on port T, preventing radiator damage and other malfunctions.

[0061] Comparatively, in Chinese patent application CN210461217U, the high-flow spool valve uses an M-type function. In the neutral position, port P is connected to port T via the valve stem, achieving neutral unloading. In the reversing position, the valve stem disconnects port P from port T, allowing normal pumping operation. However, using the valve stem's neutral M-type unloading function results in a sudden release of high-pressure oil into the return oil channel, causing a large pressure surge that can easily damage components such as the radiator. In Chinese patent application CN112096683A, for example, the valve stem uses an O-type function, which cannot unload, so a solenoid unloading valve is added. However, in low temperatures during winter, the reversing of the high-flow spool valve slows down. Often, after the solenoid unloading valve closes, the high-flow spool valve has not yet reversed to its correct position and remains in the O-type function position. At this time, port P is a closed cavity, generating a pressure surge. This pressure surge at port P can cause the engine to slow down or stall. To address this, the energization and closure delay time of the electromagnetic unloading valve can be increased to avoid pressure surges at the pumping port of the main pump. However, this also reduces pumping efficiency and lowers product reliability due to the addition of the electromagnetic unloading valve.

[0062] To achieve the integration of the directional control valve and the unloading valve and to avoid oil shock, as an example, the directional control valve 100 of this embodiment may include:

[0063] The directional valve body 2 includes an axially oriented directional valve stem cavity 3, and an inlet cavity P, a return cavity T, and a working cavity extending to the directional valve stem cavity 3; and

[0064] The reversing valve stem 1 is slidably disposed in the reversing valve stem cavity 3, and an internal flow channel is provided inside the reversing valve stem 1;

[0065] The unloading valve 200 is installed on the valve wall of the reversing valve body 2. The hydraulic control chamber of the unloading valve 200 (i.e. the spring chamber of the unloading valve 200 shown in the figure) extends to the reversing valve stem chamber 3 through the flow channel inside the valve wall. At the end of the valve stem, the flow channel inside the valve wall is aligned and connected to the inlet chamber P. At the midpoint of the valve stem, the flow channel inside the valve wall can connect to the return chamber T.

[0066] As can be seen, by configuring the flow channels within the valve wall of the hydraulic control chamber of the unloading valve 200, the flow channels within the valve stem of the reversing valve stem 1, and their positions within the reversing valve body 2, the stroke of the reversing valve stem 1 can be used to control the opening or closing of the unloading valve 200. Specifically, the unloading valve 200 can switch to an unloading closed state at the end of the valve stem's stroke and to an unloading open state at the midpoint of the valve stem's stroke. Therefore, compared to using a separate unloading solenoid valve, the unloading solenoid valve can be eliminated, and the unloading valve can be opened or closed simply by controlling it through the reversing valve stem.

[0067] Specifically, at the midpoint of the valve stem's stroke position, to ensure that the flow channel within the valve wall can connect to the return oil chamber T, Figure 3 The directional valve stem 1 shown may include a stop groove 12, which is used to connect the flow channel inside the valve wall to the return oil chamber T when the valve stem is in the midpoint stroke position. Figure 1 As shown. In addition, the reversing valve stem 1 may also include a guide groove 11, which is used to control the selective connection of the working oil chamber to the inlet oil chamber P or the return oil chamber T, as will be described in detail below.

[0068] See Figure 1 At this point, the directional valve stem 1 is in the midpoint of its stroke. The oil in the hydraulic control chamber of the unloading valve 200 connects to the return oil flow channel L and the return oil chamber T through the internal flow channel of the valve wall and the stop groove 12. As the pressure in the hydraulic control chamber gradually decreases, the pressure oil at port P gradually opens the valve port of the unloading valve 200, connecting the inlet chamber P and the return oil chamber T, thus directly unloading and returning the oil. This avoids the problem of pressure shock caused by the abrupt direct connection between the inlet chamber P and the return oil chamber T at the midpoint of the valve stem stroke. In other words, at the midpoint of the valve stem stroke, because the unloading of the unloading valve spring chamber requires time, there is also a delay between ports P and T before unloading can begin, meaning that there will be no pressure shock at port T.

[0069] Since the pressure oil at port P will be unloaded and returned by opening the unloading valve 200 at the midpoint of the valve stem stroke position, the directional valve 100 itself can be a three-position four-way valve with O-type neutral position function. The three-position four-way valve with O-type neutral position function is more conventional, with simple structure and low cost.

[0070] In this embodiment, to achieve high-flow unloading and avoid pressure shock, both the inlet chamber P and the return chamber T employ relatively large cross-sectional channels. Meanwhile, the valve stem inner flow channel and the valve wall inner flow channel are used for establishing or releasing oil pressure in the hydraulic control chamber of the unloading valve 200; therefore, they employ relatively small cross-sectional channels to provide delay or damping effects. As an example, the flow cross-sectional area of ​​both the valve stem inner flow channel and the valve wall inner flow channel should not exceed 1 / 5 of the minimum flow cross-sectional area of ​​the inlet chamber P or the return chamber T.

[0071] Based on achieving the aforementioned reversing and unloading functions, and to achieve a simplified layout of the oil passages and chambers, see [reference needed]. Figure 2 On the reversing valve body 2, the unloading valve 200 is centrally located and radially distributed. The inlet chamber P extends to the valve port end of the reversing valve body 2. The working oil chambers include a first working oil chamber B and a second working oil chamber A located on both axial sides of the inlet chamber P. The return oil chamber T is located on the first axial side of the inlet chamber P and is spaced apart on the axial outer side of the first working oil chamber B. The return oil chamber T is connected to the valve port end of the reversing valve body 2 through a return oil internal flow channel L, which extends to the second axial side of the inlet chamber P and is spaced apart on the axial outer side of the second working oil chamber A. Therefore, in this reversing valve 100, when the reversing valve stem 1 moves to the neutral position, it is the aforementioned valve stem midpoint stroke position; when the reversing valve stem 1 moves to the left or right end, it is the working valve position or the valve stem end stroke position. Of course, this is only an example. Figures 1 to 3 The directional control valve 100 shown is a three-position four-way electro-hydraulic directional control valve. See [link / reference]. Figure 7 The schematic diagram is shown, but obviously the directional valve 100 can have more valve positions and oil ports.

[0072] Specifically Figure 7 The three-position four-way electro-hydraulic directional valve shown is used to realize the directional switching function of the directional valve 100 and its unloading function in conjunction with the unloading valve 200. (See [reference needed]). Figure 3 The aforementioned valve stem internal flow channel may include a first valve stem internal flow channel 13 and a second valve stem internal flow channel 14 disposed at both axial ends of the reversing valve stem 1; see also Figure 2 The valve wall internal flow channel may include a first valve wall internal flow channel 21 and a second valve wall internal flow channel 22 extending from the hydraulic control chamber toward both axial sides; wherein, the outer axial end of the first valve stem internal flow channel 13 is used to align with the first valve wall internal flow channel 21 and the inner axial end is used to connect to the first working oil chamber B, and the outer axial end of the second valve stem internal flow channel 14 is used to align with the second valve wall internal flow channel 22 and the inner axial end is used to connect to the second working oil chamber A.

[0073] The symmetrical design of the valve stem inner flow channel and the valve wall inner flow channel facilitates the connection between the hydraulic control chamber of the unloading valve 200 and the relatively high-pressure oil chambers in the first working oil chamber B and the second working oil chamber A through the valve wall inner flow channel and the valve stem inner flow channel when the reversing valve stem 1 moves to the left end of the valve stem stroke position or the right end of the valve stem stroke position, thereby closing the unloading valve 200.

[0074] For ease of manufacturing, each of the following flow channels—the first valve stem inner flow channel 13, the second valve stem inner flow channel 14, the first valve wall inner flow channel 21, and the second valve wall inner flow channel 22—includes both axial and radial flow channels. It should be noted that... Figure 3 In the first valve stem inner flow channel 13 and the second valve stem inner flow channel 14 shown, due to the sectional view angle, their respective radial flow channels are only shown in the form of circles.

[0075] In this embodiment, such as Figure 1 The directional valve assembly shown may also include a relief valve 300, which is integrated into the valve wall of the directional valve body 2 and has its valve port located between the return oil inner flow channel L and the inlet oil chamber P. With the relief valve 300 integrated, the directional valve assembly has a higher degree of integration, a more compact structure, and more comprehensive functions. The return oil inner flow channel L extends to the second axial side of the inlet oil chamber P and is spaced apart on the axial outer side of the second working oil chamber A. This not only facilitates the connection of the hydraulic control chamber of the unloading valve 200 to the return oil chamber T via the gear slot 12, but also facilitates the installation of the relief valve 300.

[0076] In addition, to facilitate high-flow-rate oil return, the unloading valve 200 adopts a cartridge valve form. See also Figure 7 With the adoption of cartridge valves, even when the O-type neutral position directional valve is in the neutral position, the high-pressure oil at port P can open the cartridge valve in the forward direction, thereby achieving large-flow unloading without causing pressure accumulation or pressure shock to the oil inlet chamber P of the directional valve.

[0077] Based on the above, this application also discloses a pumping hydraulic system, including a pumping cylinder assembly and the aforementioned directional valve assembly, wherein the directional valve 100 is used to control the pumping cylinder assembly. Through the integrated and optimized design of the aforementioned directional valve assembly, not only is the integration high and the cost low, but it also operates smoothly, and the unloading during the directional switching process is timely, without causing pressure shock.

[0078] Specifically, during the pumping reversing process, the reversing valve stem 1 controls the opening or closing of the unloading valve 200, which avoids the pressure surge at port P and significantly reduces the instantaneous pressure surge of high-pressure oil at port P on the return oil chamber T. See also Figure 7 When the reversing valve 100 is in the neutral position, the spring chamber of the unloading valve 200 can be connected to the return oil chamber T from both ends through the flow channel inside the valve wall and the stop groove 12, so that the unloading valve 200 opens under the action of the pressure oil in the oil inlet chamber P, and the pumping port of the main pump is unloaded.

[0079] As the reversing valve stem 1 moves from the middle position to the left until it reaches the bottom, the reversing stroke of the valve stem increases, which sequentially achieves the following: the left end of the shift groove 12 disconnects the connection between the second valve wall inner flow channel 22 and the return oil chamber T; the inlet oil chamber P connects to the first working oil chamber B; the second working oil chamber A connects to the return oil chamber T; the right end of the shift groove 12 disconnects the connection between the first valve wall inner flow channel 21 and the return oil chamber T; the first valve stem inner flow channel 13 connects the first working oil chamber B and the first valve wall inner flow channel 21; the unloading valve 200 closes; and the main pump pressure oil enters the first working oil chamber B through the inlet oil chamber P, driving the pumping cylinder assembly to operate.

[0080] As the reversing valve stem 1 moves from the center position to the right until it reaches the bottom, the reversing stroke of the valve stem increases, and the right end of the shift groove 12 disconnects the first valve wall inner flow channel 21 from the return oil chamber T, the inlet oil chamber P connects to the second working oil chamber A, and the first working oil chamber B connects to the T chamber. The left end of the shift groove 12 disconnects the second valve wall inner flow channel 22 from the return oil chamber T, the second valve stem inner flow channel 14 connects the second working oil chamber A with the second valve wall inner flow channel 22, the unloading valve 200 closes, and the main pump pressure oil enters the second working oil chamber A through the inlet oil chamber P, driving the pumping cylinder group to operate.

[0081] As can be seen, the unloading solenoid valve is eliminated in the pumping hydraulic system of this application. The opening and closing of the unloading valve 200 is controlled by the reversing valve stem 1, avoiding pressure shocks at the pumping port of the main pump during pumping reversal. Furthermore, damping can be installed in the flow channel within the valve stem of the reversing valve stem 1 to limit the opening speed of the unloading valve 200, preventing pressure oil from the pumping port of the main pump from impacting the return oil chamber T, which could cause excessively high instantaneous pressure in the return oil chamber T and damage components such as the radiator. In summary, this application uses the reversing valve stem 1 to control the opening and closing of the unloading valve 200, avoiding pressure shocks from the pumping port of the main pump during reversal, preventing engine speed drops or stalling. During pumping reversal, limiting the opening speed of the unloading valve 200 by the reversing valve stem 1 significantly reduces the instantaneous pressure shock of the high-pressure oil from the main pump on the return oil chamber T, preventing radiator damage and other malfunctions.

[0082] 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.

[0083] 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.

[0084] 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.

[0085] 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 high-low pressure switching valve, used for high-low pressure switching control of a pumping cylinder assembly, characterized in that, The high / low pressure switching valve (400) includes: The switching valve body (4) has an axially oriented switching valve stem cavity (5) inside. The valve wall of the switching valve body (4) is provided with a plurality of first side oil ports and a plurality of second side oil ports extending to the switching valve stem cavity (5). The plurality of second side oil ports include a rod cavity connection oil port group for connecting to the rod cavity of the pumping cylinder group and a rodless cavity oil port group for connecting to the rodless cavity of the cylinder. The switching valve stem (6) is slidably disposed in the switching valve stem cavity (5) and is used to control multiple first side oil ports to selectively connect to the rod chamber connection oil port group or to the rodless chamber oil port group according to the valve stem movement stroke; The valve wall of the switching valve body (4) is also provided with a filling and draining oil chamber (7) extending to the switching valve stem chamber (5), and the switching valve stem (6) is also provided with a valve stem filling and draining oil passage (64), which is used to connect the filling and draining oil chamber (7) with the second side oil port. In the switching valve stem cavity (5), a plurality of first side oil ports are arranged axially at intervals. One of the rod chamber connecting oil port group and the rodless chamber oil port group is arranged at intervals between the plurality of first side oil ports, and the other is arranged symmetrically on the axial outer side of the plurality of first side oil ports. Wherein, at the axial end of the switching valve stem cavity (5), the valve wall of the switching valve body (4) is also provided with an end communication cavity (C) extending to the switching valve stem cavity (5). The end communication cavity (C) is used to connect each oil port in the axial outer oil port group when multiple first side oil ports are connected to the axial inner oil port group of the first side oil ports.

2. The high-low pressure switching valve according to claim 1, characterized in that, The first side port includes a first port (A') and a second port (B'), the rod cavity connection port group includes a first rod cavity connection port (A1) and a second rod cavity connection port (B1), and the rodless cavity connection port group includes a first rodless cavity connection port (A2) and a second rodless cavity connection port (B2). The rod cavity connection port group is the axial outer port group. The end communication cavity (C) is arranged at the same axial end of the switching valve stem cavity (5) with one of the first rod cavity connection port (A1) and the second rod cavity connection port (B1) at intervals, and is in communication with the other of the first rod cavity connection port (A1) and the second rod cavity connection port (B1).

3. The high-low pressure switching valve according to claim 1, characterized in that, The switching valve stem (6) includes: An inner oil port connecting groove (61) is arranged in the center and an outer oil port connecting groove (62) is arranged at intervals on the outer side of the inner oil port connecting groove (61) along the axial direction. End communication groove (63) is used to control the connection between the end communication cavity (C) and the oil port in the adjacent axially outer oil port group.

4. The high-low pressure switching valve according to claim 3, characterized in that, One end of the valve stem refill oil passage (64) extends to connect the inner oil port connecting groove (61), and the other end extends axially outward to the outside of the outer oil port connecting groove (62) and is used to connect the refill oil chamber (7).

5. The high-low pressure switching valve according to claim 3, characterized in that, The oil filling and draining chamber (7) and the end connecting groove (63) are located at both ends of the switching valve stem chamber (5) along the axial direction.

6. The high-low pressure switching valve according to any one of claims 1 to 5, characterized in that, The high-low pressure switching valve (400) also integrates a replenishment and drain valve (500), and the replenishment outlet of the replenishment and drain valve (500) is connected to the replenishment and drain chamber (7).

7. The high-low pressure switching valve according to claim 6, characterized in that, The oil filling and draining valve (500) is integrally cast onto the switching valve body (4).

8. A pumping control valve assembly, characterized in that, The pumping control valve group includes a reversing valve group for controlling the pumping cylinder group and a high-low pressure switching valve according to any one of claims 1 to 7, wherein a plurality of first side oil ports are connected to the working oil ports of the reversing valve group.

9. A pumping hydraulic system, characterized in that, The pumping hydraulic system includes the pumping control valve assembly according to claim 8.

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