Reversing valve group and operation machine

Abstract

The invention belongs to the technical field of hydraulic pressure and provides a reversing valve group and an operation machine.The reversing valve group comprises a main reversing valve, a pilot oil way and a hydraulic control one-way valve, the main reversing valve is provided with an in-group working oil port and a hydraulic control reversing end, and the pilot oil way is connected with the hydraulic control reversing end; the hydraulic control one-way valve is connected with an in-group working oil port of the main reversing valve and is configured to be conducted and reversely cut off when the in-group working oil port outputs hydraulic oil outwards, a one-way valve pilot port used for controlling reverse conduction of the hydraulic control one-way valve is formed in the hydraulic control one-way valve, and the one-way valve pilot port is communicated with the pilot oil way. According to the valve bank, the hydraulic control one-way valve can be synchronously and stably opened along with reversing of the main reversing valve, and opening control of the hydraulic control one-way valve is not interfered by load fluctuation.

Description

Technical Field

[0001] The present invention belongs to the technical field of operating machinery, and in particular relates to a reversing valve group and an operating machinery. Background Art

[0002] When operating machinery, certain actuators must maintain a specific posture for extended periods. For example, in a crane's luffing mechanism, once the boom is in place, it must maintain that specific angle for extended periods. Existing technology typically switches the reversing valve to a neutral position (shutoff position) to shut off the oil flow and lock the cylinder. However, internal leakage in the reversing valve causes the pressure on the pressure-bearing side of the cylinder to slowly release, causing the boom's posture to drift.

[0003] To overcome this problem, the prior art has an anti-leakage reversing valve group that integrates a hydraulically controlled one-way valve at the working oil port of an ordinary reversing valve. When the reversing valve is in the middle position, the hydraulically controlled one-way valve relies on the spring force to lock the oil port, blocking the oil cylinder from leaking oil into the reversing valve. However, the pilot control oil circuit of the one-way valve is usually connected to the pressure oil circuit, and the pressure of the pressure oil circuit will fluctuate with the load, resulting in unstable pilot oil pressure of the one-way valve. When the reversing valve is cut out of the middle position, the uncertainty of the pilot pressure will cause the one-way valve to delay the opening timing, fluctuate the opening degree, or oscillate in opening and closing, which will eventually lead to nonlinearity, hysteresis and uncontrollable response between the spool displacement instruction of the reversing valve and the actual output flow. Summary of the Invention

[0004] In view of the above-mentioned defects or shortcomings, the present invention provides a reversing valve group and an operating machine, aiming to solve the technical problem of poor opening stability of the hydraulically controlled one-way valve in the existing anti-leakage reversing valve group.

[0005] To achieve the above-mentioned objectives, the present invention provides a reversing valve group, which includes a main reversing valve, a pilot oil circuit and a hydraulically controlled one-way valve. The main reversing valve is provided with an internal working oil port and a hydraulically controlled reversing end. The pilot oil circuit is connected to the hydraulically controlled reversing end. The hydraulically controlled one-way valve is connected to the internal working oil port of the main reversing valve and is configured to be conductive when the internal working oil port outputs hydraulic oil to the outside and to be cut off in the reverse direction. A one-way valve pilot port for controlling the reverse conduction of the hydraulically controlled one-way valve is provided in the hydraulically controlled one-way valve, and the one-way valve pilot port is connected to the pilot oil circuit.

[0006] In this embodiment, the reversing valve group includes a main valve body provided with a valve core channel and a main valve core movably arranged in the valve core channel. The main valve body is also provided with a pressure oil port, a return oil port and a working oil port within the group. The pressure oil port, the return oil port and the working oil port within the group are respectively connected to the valve core channel. The pilot oil circuit is opened on the main valve body. The main valve core is used to control the connection and disconnection of the working oil port within the group with the pressure oil port and the return oil port according to the moving position. At least one axial end of the main valve core is a hydraulically controlled reversing end, and the hydraulically controlled one-way valve is arranged on the working oil port within the group.

[0007] In this embodiment, the main valve core has a shut-off valve position and a first valve position. The main valve core is used to shut off the working oil port from the pressure oil port and the return oil port in the shut-off valve position control group respectively. The main valve core is used to connect the working oil port and the return oil port in the first valve position control group. One axial end of the main valve core is the first reversing end, which is a hydraulically controlled reversing end and forms a first reversing control chamber for controlling the movement of the main valve core toward the first valve position. The first reversing control chamber is connected to the pilot oil circuit.

[0008] In this embodiment, the main valve core also has a second valve position, and the main valve core is used to connect the working oil port and the pressure oil port in the second valve position control group. The main valve core is also provided with a second reversing end opposite to the first reversing end, and the second reversing end is provided with a driving structure for controlling the movement of the main valve core toward the second valve position.

[0009] In this embodiment, the drive structure includes a return spring acting on the second reversing end of the main valve core, and / or the second reversing end is a hydraulically controlled reversing end, and the drive structure includes a second reversing control chamber formed on the second reversing end.

[0010] In this embodiment, the main valve body is provided with an installation channel opposite to the working oil port in the group. The hydraulically controlled one-way valve is arranged in the installation channel and includes a one-way valve core and an elastic supporting member. The one-way valve core extends from the installation channel and seals the port of the working oil port in the group. The elastic supporting member elastically supports the end of the one-way valve core facing away from the working oil port in the group. The pilot port of the one-way valve is used to drive the one-way valve core to move in the opposite direction of the elastic force applied by the elastic supporting member when the pilot pressure oil is introduced into the pilot oil circuit.

[0011] In this embodiment, the hydraulically controlled one-way valve also includes a cylinder body and a piston respectively arranged coaxially with the one-way valve core. The cylinder body is arranged in the installation channel. The piston is movably arranged in the cylinder body and forms a one-way valve pilot port between the cylinder body and the one-way valve core. One end of the one-way valve core facing away from the working oil port in the group extends into the cylinder body and is linked with the piston.

[0012] In this embodiment, the hydraulically controlled one-way valve further includes a valve seat, which is arranged at one end of the one-way valve core facing away from the working oil port in the group, and the elastic supporting member elastically supports between the valve seat and the one-way valve core.

[0013] In this embodiment, a sharp edge is formed on the port of the working oil port in the group, and a wedge-shaped surface for sealing with the sharp edge is formed on the one-way valve core.

[0014] To achieve the above objectives, the present invention further provides an operating machine, wherein the operating machine includes the reversing valve group described above.

[0015] Through the above technical solution, the reversing valve group provided by the embodiment of the present invention has the following beneficial effects: When the pilot oil circuit drives the main reversing valve to change direction, the pilot pressure oil will simultaneously enter the one-way valve pilot port of the hydraulically controlled one-way valve and control the reverse conduction function of the hydraulically controlled one-way valve to open synchronously. Since the hydraulically controlled reversing end of the main reversing valve and the one-way valve pilot port of the hydraulically controlled one-way valve share the pilot oil circuit, and the oil pressure of the pilot oil circuit is almost unaffected by load changes, it can ensure that the hydraulically controlled one-way valve is not affected by load pressure fluctuations during the opening process, and ensure that the hydraulically controlled one-way valve can be opened synchronously and smoothly with the main reversing valve under a constant pilot pressure. In summary, the hydraulically controlled one-way valve in this embodiment can be opened synchronously and smoothly with the reversing of the main reversing valve, so that the valve core displacement instruction of the main reversing valve can be converted into flow output linearly and without delay, significantly improving the micro-control accuracy and dynamic response reliability of the actuator.

[0016] Other features and advantages of the present invention will be described in detail in the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The accompanying drawings are used to provide an understanding of the present invention and constitute a part of the specification. Together with the following detailed description, they are used to explain the present invention but do not constitute a limitation of the present invention. In the accompanying drawings: Figure 1 It is a hydraulic principle diagram of the prior art anti-leakage reversing valve group; Figure 2 is a hydraulic principle diagram of a reversing valve group according to an embodiment of the present invention; Figure 3 2 is a schematic structural diagram of the connection between the pilot oil circuit and the pilot port of the hydraulically controlled one-way valve according to an embodiment of the present invention; Figure 4 is an overall axial cross-sectional view of the reversing valve group in the shut-off valve position according to an embodiment of the present invention; Figure 5 According to an embodiment of the present invention Figure 4 An enlarged schematic diagram of S; Figure 6 is a schematic diagram of the flow direction of hydraulic oil in the main valve body when the main reversing valve is in the second valve position according to an embodiment of the present invention; Figure 7 3 is a schematic diagram of the flow direction of hydraulic oil in the main valve body when the main reversing valve is in the first valve position according to an embodiment of the present invention.

[0018] Description of Reference Numerals 1. Main reversing valve; 1a. Hydraulic-controlled reversing end; A. Internal working oil port; P. Pressure oil port; T. Oil return port; A1. External working oil port; 11. Main valve body; 12. Main valve core; 12a. First reversing control chamber; 12b. Second reversing control chamber; 12c. Return spring; 13. Sharp edge; 2. Pilot oil circuit; 3. Hydraulic-controlled check valve; 3a. Check valve pilot port; 31. Check valve core; 32. Elastic supporting member; 33. Cylinder body; 34. Piston; 35. Valve seat. DETAILED DESCRIPTION

[0019] The specific embodiments of the present invention are described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are only used to illustrate and explain the present invention and are not intended to limit the present invention.

[0020] The reversing valve assembly of the present invention will be described below with reference to the accompanying drawings.

[0021] like Figure 1 As shown, existing anti-leakage reversing valve assemblies (such as the second electro-hydraulic controlled directional valve-20 and hydraulically controlled check valve-21 in reference document CN205101318U) achieve zero leakage in the directional valve's neutral position by installing a hydraulically controlled check valve at the working oil port of the second electro-hydraulic controlled directional valve. However, its pilot oil port is directly connected to the working oil port of the directional valve. While this design allows for the synchronous opening of the hydraulically controlled check valve's reverse conduction function when the directional valve is switched to the corresponding valve position, the pilot pressure for opening the hydraulically controlled check valve in this scheme is significantly affected by load fluctuations. This is especially true for engineering machinery capable of performing complex movements, where the hydraulic pump simultaneously supplies oil to multiple actuators. Load fluctuations in these other actuators can easily cause the valve core of the hydraulically controlled check valve within the anti-leakage reversing valve assembly to vibrate and oscillate.

[0022] In order to overcome the above problems, the present invention provides a reversing valve group, such as Figure 2 、 Figure 3 and Figure 4 As shown, the reversing valve group includes a main reversing valve 1, a pilot oil circuit 2 and a hydraulically controlled one-way valve 3.

[0023] The main reversing valve 1 is a hydraulically controlled reversing valve and is provided with a hydraulically controlled reversing end 1 a . The main reversing valve 1 has at least one internal working oil port A for external connection to an actuator.

[0024] The pilot oil circuit 2 is connected to the hydraulic control reversing end 1 a of the main reversing valve 1 so as to control the main reversing valve 1 to switch to different valve positions.

[0025] The hydraulically controlled check valve 3 is connected to the internal working oil port A of the main reversing valve 1 and is configured to open when the internal working oil port A is outputting hydraulic oil, and to block the flow in the opposite direction. In other words, the hydraulically controlled check valve 3 has a first oil port, a second oil port, and a check valve pilot port 3a. The hydraulically controlled check valve is configured to open when hydraulic oil flows from the first oil port to the second oil port, and to block the flow in the opposite direction.

[0026] The first oil port is connected to the internal working oil port A of the group, and the second oil port is used to connect externally to the actuator. When hydraulic oil flows outward to the actuator through the internal working oil port A, the first oil port, and the second oil port, hydraulically controlled check valve 3 is in the conducting state. When hydraulic oil in the actuator flows to the internal working oil port A of the group through the second oil port, hydraulically controlled check valve 3 is in the blocked state. Hydraulically controlled check valve 3 is provided with a check valve pilot port 3a for controlling the synchronous opening of the reverse conduction function of hydraulically controlled check valve 3. Check valve pilot port 3a is connected to pilot oil circuit 2.

[0027] When the pilot oil circuit 2 drives the main reversing valve 1 to change direction, the pilot pressure oil will simultaneously enter the one-way valve pilot port 3a of the hydraulically controlled one-way valve 3 and control the reverse conduction function of the hydraulically controlled one-way valve 3 to open synchronously. Since the hydraulically controlled reversing end 1a of the main reversing valve 1 and the one-way valve pilot port 3a of the hydraulically controlled one-way valve 3 share the pilot oil circuit 2, and the oil pressure in the pilot oil circuit 2 is almost unaffected by load changes, it can ensure that the hydraulically controlled one-way valve 3 is not affected by load pressure fluctuations during or after opening, ensuring that the hydraulically controlled one-way valve 3 can be opened synchronously and smoothly with the main reversing valve 1 under a constant pilot pressure. In summary, the hydraulically controlled one-way valve 3 in this embodiment can be opened synchronously and smoothly with the reversing of the main reversing valve 1, so that the valve core displacement command of the main reversing valve 1 can be converted into flow output linearly and without delay, significantly improving the micro-control accuracy and dynamic response reliability of the actuator.

[0028] The reversing valve group in this embodiment is an integrated valve group, that is, the main reversing valve 1 and the hydraulically controlled one-way valve 3 share a common valve body.

[0029] Specifically, from a structural perspective, Figure 3 and Figure 4 As shown, the reversing valve group in this embodiment consists of a main valve body 11 and a main valve core 12. A valve core passage is provided on the main valve body 11, and a pressure oil port P, a return oil port T, and an internal working oil port A, each of which is connected to the valve core passage, are also provided on the main valve body 11. A pilot oil circuit 2 is provided on the main valve body 11. The main valve core 12 is movably disposed within the valve core passage and is used to control the connection and disconnection of the internal working oil port A with the pressure oil port P and the return oil port T, respectively, based on the movement position. At least one axial end of the main valve core 12 is a hydraulically controlled reversing end 1a. The pilot oil circuit 2 on the main valve body 11 extends to communicate with the hydraulically controlled reversing end 1a. A hydraulically controlled check valve 3 is disposed on the internal working oil port A. The pilot oil circuit 2 on the main valve body 11 also extends to communicate with the pilot port 3a of the check valve.

[0030] When the pilot pressure oil of the pilot oil circuit 2 flows to the hydraulically controlled reversing end 1a of the main valve core 12, the main valve core 12 will switch the valve position to connect one of the pressure oil port P and the return oil port T with the working oil port A in the group. Since the one-way valve pilot port 3a of the hydraulically controlled one-way valve 3 and the hydraulically controlled reversing end 1a of the main valve core 12 share the pilot oil circuit 2, the pilot pressure oil in the pilot oil circuit 2 will drive the reverse conduction function of the hydraulically controlled one-way valve 3 to open synchronously when driving the main valve core 12 to reverse. That is, the reverse conduction function of the hydraulically controlled one-way valve 3 will also be opened synchronously with the reversing of the main valve core 12. The mechanism of the hydraulically controlled one-way valve 3 opening synchronously with the reversing of the main valve core 12 can ensure the precise coordination between the hydraulically controlled one-way valve 3 and the main reversing valve 1, and the opening driving oil pressure of the hydraulically controlled one-way valve 3 and the reversing driving oil pressure of the main valve core 12 are stable oil pressures, thereby completely avoiding a series of problems such as hysteresis and large flow fluctuations caused by the asynchronous and unstable actions of the two valves.

[0031] Furthermore, the opening timing of the hydraulically controlled one-way valve 3 can be coordinated with the specific valve position of the main valve core 12 to ensure the normal oil inlet and outlet operation of the actuator.

[0032] Specifically, if Figure 4 and Figure 7 As shown, the main valve core 12 in this embodiment has a shut-off valve position and a first valve position relative to the main valve body 11. The main valve core 12 is used to shut off the working oil port A with the pressure oil port P and the return oil port T in the shut-off valve position control group respectively. The main valve core 12 is also used to connect the working oil port A with the return oil port T in the first valve position control group. One axial end of the main valve core 12 is the first reversing end, which is the hydraulically controlled reversing end 1a and forms a first reversing control chamber 12a for controlling the main valve core 12 to move toward the first valve position. The first reversing control chamber 12a is connected to the pilot port 3a of the one-way valve.

[0033] like Figure 6 As shown, the main valve core 12 also has a second valve position. The main valve core 12 is used to connect the working oil port A and the pressure oil port P in the second valve position control group. The main valve core 12 is also provided with a second reversing end opposite to the first reversing end. The second reversing end is provided with a driving structure for controlling the movement of the main valve core 12 toward the second valve position.

[0034] Taking the reversing valve group controlling the lifting cylinder of an aerial work platform as an example, the main valve body 11 can also be provided with an external working oil port A1. This external working oil port A1 is connected to the second oil port of the hydraulically controlled one-way valve and is used to connect to the rodless chamber of the lifting cylinder. When the lifting platform needs to be raised, the main valve core 12 can be controlled to switch to the second valve position. At this time, the pressure oil from the pressure oil port P will flow through the internal working oil port A of the group, the hydraulically controlled one-way valve 3, and the external working oil port A1 of the reversing valve group to the rodless chamber of the lifting cylinder, thereby driving the lifting cylinder to extend. Since the internal working oil port A of the group outputs hydraulic oil, the hydraulically controlled one-way valve 3 is in a forward-conducting state. Therefore, whether or not there is pilot pressure oil in the one-way valve pilot port 3a of the hydraulically controlled one-way valve 3 does not affect the extension of the lifting cylinder.

[0035] When the aerial work platform is lifted to a certain height and remains at that height, the pilot oil circuit 2 can be controlled to be disconnected from the pilot pressure oil source. At this time, the main valve core 12 will be reset from the second valve position to the shut-off valve position under the action of the drive structure. When the aerial work platform is stationary at a high altitude, the rodless chamber of the lifting cylinder bears the weight of the aerial work platform, resulting in a high hydraulic oil pressure in the rodless chamber of the lifting cylinder. Because the hydraulically controlled one-way valve 3 is integrated into the working oil port A within the group and the hydraulically controlled one-way valve 3 has a reverse shut-off function, it can prevent the hydraulic oil in the rodless chamber from flowing from the external working oil port A1 into the valve core channel and leaking from the gap between the main valve core 12 and the main valve body 11.

[0036] When the aerial work platform needs to be lowered, pilot oil circuit 2 injects pilot pressure oil into first reversing control chamber 12a, driving main valve spool 12 to its first position. Simultaneously, the reverse conduction function of hydraulically controlled check valve 3 is activated. The hydraulic oil in the rodless chamber is then returned through external working oil port A1, hydraulically controlled check valve 3, internal working oil port A, and return oil port T, causing the lift cylinder to retract. Because the pressure of the pilot hydraulic oil in hydraulically controlled check valve 3 is unaffected by the load, the check valve opens with zero oscillation and high precision, preventing fluctuations in the control valve group's flow stability caused by vibration of the hydraulically controlled check valve spool.

[0037] like Figure 4 As shown, in this embodiment, the driving structure may only include a return spring 12c acting on the main valve core 12. Through the return spring 12c, the main valve core 12 can be driven to automatically return to the middle stop valve position when the first reversing control chamber 12a is at low pressure. In order to facilitate the switching of the main valve core 12 between the first valve position and the second valve position, the pilot oil circuit 2 can be a variable pressure oil circuit with variable oil pressure. By changing the oil pressure of the pilot oil circuit 2, different driving forces can be formed to balance the return spring 12c, so that the main valve core 12 can stay in different positions.

[0038] Of course, in this embodiment, to facilitate the active switching of the main valve core 12 to the second valve position, the second reversing end can also be configured as a hydraulically controlled reversing end 1a, and a second reversing control chamber 12b similar to the first reversing control chamber 12a can be formed on the second reversing end. Alternatively, the second reversing end can be an electromagnetic reversing end, and an electromagnet for driving reversing can be provided on the second reversing end.

[0039] like Figure 2 As shown, in this embodiment, the main reversing valve 1 can be provided with a plurality of intra-group working oil ports A, and the plurality of intra-group working oil ports A can be optionally installed with hydraulically controlled one-way valves according to usage requirements.

[0040] like Figure 4 and Figure 5 As shown, in this embodiment, the main valve body 11 is provided with a mounting channel opposite to the working oil port A in the group. The hydraulically controlled one-way valve 3 is arranged in the mounting channel and includes a one-way valve core 31 and an elastic supporting member 32. The one-way valve core 31 extends from the mounting channel and seals the port of the working oil port A in the group. The elastic supporting member 32 elastically supports the end of the one-way valve core 31 facing away from the working oil port A in the group. The one-way valve pilot port 3a is used to drive the one-way valve core 31 to move in the opposite direction of the elastic force applied by the elastic supporting member when the pilot pressure oil is introduced into the pilot oil circuit.

[0041] like Figure 6 As shown, when the main valve core 12 is in the second valve position, when the working oil port A and the pressure oil port P in the group are connected, since the installation channel and the working oil port in the group are arranged relative to each other, the pressure oil entering from the pressure oil port P to the working oil port will move the one-way valve core 31 in the direction of retracting the installation channel, thereby realizing the positive passive opening of the hydraulically controlled one-way valve 3.

[0042] like Figure 4 As shown, in the stop valve position, there is no high-pressure oil in the working oil port of the group, and the one-way valve core 31 blocks the working oil port of the group under the action of the elastic supporting member 32, achieving zero leakage when the reversing valve group is in the middle position.

[0043] like Figure 5 and Figure 7 As shown, in the first valve position, the pilot oil circuit 2 acts on the pilot port 3a of the one-way valve to drive the one-way valve core 31 to move in the direction of retracting the installation channel, thereby realizing the reverse active opening of the hydraulically controlled one-way valve 3.

[0044] In this embodiment, there are many ways to realize the reverse active opening drive of the hydraulically controlled one-way valve 3, such as Figure 5In this embodiment, the hydraulically controlled check valve 3 includes a cylinder 33 and a piston 34, each coaxially arranged with a check valve core 31. The cylinder 33 is disposed within the mounting passage, and the piston 34 is movably disposed within the cylinder 33, forming a check valve pilot port 3a between the cylinder 33 and the piston 34. The end of the check valve core 31, facing away from the internal working oil port A, extends into the cylinder 33 and is in operative contact with the piston 34. When oil flows into the check valve pilot port 3a, it drives the piston 34 away from the internal working oil port, thereby causing the check valve core 31 to retract into the mounting passage.

[0045] Of course, in other embodiments, a cylinder 33 and a piston 34 can be installed on the side of the one-way valve core 31 facing the working oil port, and the one-way valve core 31 can be driven in the direction of retracting into the installation channel by the piston 34. Alternatively, a stepped groove can be provided on the one-way valve core, and the area difference of the stepped shaft can be used to drive the one-way valve core.

[0046] like Figure 5 As shown, in this embodiment, the hydraulically controlled one-way valve 3 further includes a valve seat 35, which is disposed at the end of the one-way valve core 31 facing away from the internal working oil port A. An elastic abutment 32 is elastically abutted between the valve seat 35 and the one-way valve core 31. The valve seat 35 allows the one-way valve core 31 and the elastic abutment 32 to be retained within the installation passage.

[0047] In this embodiment, the elastic resisting member 32 may be a spring.

[0048] like Figure 5 As shown, in this embodiment, the working oil port A within the group is formed with a sharp edge 13, and the one-way valve core 31 is formed with a wedge-shaped surface for sealing with the sharp edge 13. The contact between the sharp edge 13 and the wedge-shaped surface enhances the sealing performance of the one-way valve core 31 with respect to the working oil port when the main reversing valve 1 is in the shut-off position.

[0049] To achieve the above objectives, the present invention further provides a work machine, wherein the work machine includes a hydraulic system, wherein the hydraulic system includes the reversing valve assembly described above. Since the reversing valve assembly adopts all the technical solutions of the above embodiments, it has at least the beneficial effects brought about by the above embodiments, and no further details are given here.

[0050] In this embodiment, the operating machine may be a crane, an excavator, a tractor, an agricultural harvester or other operating machine, but is not limited thereto.

[0051] For example, a tractor can carry different attachments to achieve specific functions. Most tractors are equipped with an attachment lift cylinder. When the tractor is traveling on a normal road with an attachment, oil is injected into the rodless chamber of the attachment lift cylinder to lift the attachment.

[0052] The external working oil port in the reversing valve group in this embodiment can be connected to the rodless chamber of the attachment lifting cylinder. When the tractor lifts the attachment and drives normally on the road, the hydraulically controlled one-way valve can ensure that after the attachment lifting cylinder lifts the attachment, there will be no internal leakage in the rodless chamber and its working oil circuit, thereby ensuring that the lifting height of the attachment remains unchanged.

[0053] When a tractor carries attachments for field operations (such as plowing, harrowing, sowing, etc.), in order to adapt to the ups and downs, ditches and stones in the field, the attachment lifting cylinder needs to be in a floating state. Therefore, the main reversing valve 1 of the rodless chamber used to control the attachment lifting cylinder needs to be switched to the first valve position, and the reverse conduction function of the hydraulically controlled one-way valve needs to be turned on.

[0054] Since the hydraulically controlled reversing end 1a of the main reversing valve 1 and the one-way valve pilot port 3a of the hydraulically controlled one-way valve 3 share the pilot oil circuit 2, and the oil pressure in the pilot oil circuit 2 is almost unaffected by load changes, it can ensure that the hydraulically controlled one-way valve 3 is not affected by load pressure fluctuations during or after the opening process, and ensure that the hydraulically controlled one-way valve 3 can be opened synchronously and smoothly with the main reversing valve 1 under a constant pilot pressure, avoiding opening oscillation of the hydraulically controlled one-way valve 3 and affecting the floating performance of the attachment lifting cylinder.

[0055] In the description of the present invention, it should be understood that the terms "first" and "second" are used for descriptive purposes only and should not be understood to indicate or imply relative importance or implicitly specify the number of the technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of such features. In the description of the present invention, "plurality" means at least two, for example, two, three, etc., unless otherwise specifically defined.

[0056] In the present invention, unless otherwise specified or limited, the terms "installed," "connected," "connect," "fixed," etc. should be understood in a broad sense. For example, they can refer to fixed connection, detachable connection, or integration; mechanical connection, electrical connection, or communication; direct connection or indirect connection through an intermediate medium; internal communication between two elements or interaction between two elements, unless otherwise specified. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0057] In the description of this specification, the reference terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" mean that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art can combine and combine different embodiments or examples described in this specification and features of different embodiments or examples without contradiction.

[0058] Although the embodiments of the present invention have been described above, it is understood that the above embodiments are illustrative and are not to be construed as limitations on the present invention. A person skilled in the art may change, modify, replace and modify the above embodiments within the scope of the present invention.

Claims

1. A reversing valve group, characterized in that: The reversing valve group includes: The main reversing valve (1) is provided with an internal working oil port (A) and a hydraulically controlled reversing end (1a); A pilot oil circuit (2) connected to the hydraulically controlled reversing end (1a); A hydraulically controlled one-way valve (3) is connected to the working oil port (A) in the group and is configured to be conductive when the working oil port (A) in the group outputs hydraulic oil outward and to be cut off in the reverse direction. A one-way valve pilot port (3a) for controlling the reverse conduction of the hydraulically controlled one-way valve (3) is provided in the hydraulically controlled one-way valve (3), and the one-way valve pilot port (3a) is communicated with the pilot oil circuit (2).

2. The reversing valve assembly according to claim 1, characterized in that: The reversing valve group comprises a main valve body (11) provided with a valve core channel and a main valve core (12) movably arranged in the valve core channel. The main valve body (11) is also provided with a pressure oil port (P), a return oil port (T) and a working oil port (A) in the group. The pressure oil port (P), the return oil port (T) and the working oil port (A) in the group are respectively connected to the valve core channel. The pilot oil circuit (2) is opened on the main valve body (11). The main valve core (12) is used to control the connection and disconnection of the working oil port (A) in the group with the pressure oil port (P) and the return oil port (T) according to the moving position. At least one axial end of the main valve core (12) is a hydraulically controlled reversing end (1a). The hydraulically controlled one-way valve (3) is arranged on the working oil port (A) in the group.

3. The reversing valve assembly according to claim 2, characterized in that: The main valve core (12) has a stop valve position and a first valve position. The main valve core (12) is used to control the working oil port (A) in the group to be cut off from the pressure oil port (P) and the return oil port (T) respectively at the stop valve position. The main valve core (12) is used to control the working oil port (A) in the group to be connected to the return oil port (T) at the first valve position. One axial end of the main valve core (12) is a first reversing end. The first reversing end is a hydraulically controlled reversing end (1a) and forms a first reversing control chamber (12a) for controlling the main valve core (12) to move toward the first valve position. The first reversing control chamber (12a) is connected to the pilot oil circuit (2).

4. The reversing valve assembly according to claim 3, characterized in that: The main valve core (12) also has a second valve position, and the main valve core (12) is used to control the communication between the working oil port (A) and the pressure oil port (P) in the group at the second valve position. The main valve core (12) is also provided with a second reversing end opposite to the first reversing end, and the second reversing end is provided with a driving structure for controlling the main valve core (12) to move toward the second valve position.

5. The reversing valve assembly according to claim 4, characterized in that: The driving structure includes a return spring (12c) acting on the second reversing end of the main valve core (12), and / or the second reversing end is a hydraulically controlled reversing end (1a), and the driving structure includes a second reversing control chamber (12b) formed on the second reversing end.

6. The reversing valve assembly according to claim 2, characterized in that: The main valve body (11) is provided with a mounting channel opposite to the working oil port (A) in the group. The hydraulically controlled one-way valve (3) is arranged in the mounting channel and includes a one-way valve core (31) and an elastic supporting member (32). The one-way valve core (31) extends from the mounting channel and seals against the port of the working oil port (A) in the group. The elastic supporting member (32) elastically supports the end of the one-way valve core (31) facing away from the working oil port (A) in the group. The one-way valve pilot port (3a) is used to drive the one-way valve core (31) to move in the opposite direction to the elastic force applied by the elastic supporting member when the pilot pressure oil is introduced into the pilot oil circuit (2).

7. The reversing valve assembly according to claim 6, characterized in that: The hydraulically controlled one-way valve (3) further comprises a cylinder (33) and a piston (34) respectively arranged coaxially with the one-way valve core (31); the cylinder (33) is arranged in the installation channel; the piston (34) is movably arranged in the cylinder (33) and forms the one-way valve pilot port (3a) between the cylinder (33) and the one-way valve core (31); an end of the one-way valve core (31) facing away from the working oil port (A) in the group extends into the cylinder (33) and is linked to the piston (34).

8. The reversing valve assembly according to claim 6 or 7, characterized in that: The hydraulically controlled one-way valve (3) further comprises a valve seat (35), wherein the valve seat (35) is arranged at an end of the one-way valve core (31) facing away from the working oil port (A) in the group, and the elastic supporting member (32) elastically supports between the valve seat (35) and the one-way valve core (31).

9. The reversing valve assembly according to claim 6 or 7, characterized in that: The port of the working oil port (A) in the group is formed with a sharp edge (13), and the one-way valve core (31) is formed with a wedge surface for sealing with the sharp edge (13).

10. A working machine, characterized in that: The working machine includes the reversing valve assembly according to any one of claims 1 to 9.

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