Variable frequency control valve group and control method thereof, hydraulic system and tamping device
By introducing a variable frequency control valve group into the tamping device, integrating an electromagnetic reversing valve and a priority flow valve, the automatic switching of the oil supply mode is realized, which solves the problems of high noise and high energy consumption caused by the fixed vibration frequency of the tamping device, and improves the energy efficiency and response speed of the system.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- CRCC HIGH TECH EQUIP CORP LTD
- Filing Date
- 2026-06-30
- Publication Date
- 2026-07-28
AI Technical Summary
The existing tamping device has a fixed vibration frequency, which results in high noise and cannot be automatically adjusted according to working conditions. This leads to high energy consumption when starting and stopping frequently, and the system is not compact or reliable enough.
The system adopts a variable frequency control valve group, which integrates a solenoid directional valve and a priority flow valve. By controlling the on/off state of the solenoid directional valve and the priority flow valve, the oil supply mode can be automatically switched to provide the hydraulic motor with matched controlled oil and meet the flow requirements under different working conditions.
It achieves efficient flow matching of hydraulic motors under different working conditions, reduces energy consumption during frequent start-stop operations, and improves the system's energy efficiency, response speed, and structural compactness, making it suitable for mobile hydraulic equipment that requires frequent start-stop operations.
Smart Images
Figure CN122467437A_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of hydraulic control valve assembly technology, specifically to a frequency conversion control valve assembly and its control method, a hydraulic system, and a tamping device. Background Technology
[0002] The tamping device, as the main working device of the tamping series of large track maintenance machinery, is used to tamp the ballast at the bottom of the sleepers on both sides of the rail, thereby improving the compaction of the ballast at the bottom of the sleepers.
[0003] The most widely used tamping device currently operates on the principle that a quantitative hydraulic pump drives a quantitative motor to rotate the eccentric shaft. The clamping cylinder mounted on the eccentric shaft journal then reciprocates under the action of the eccentric shaft, pushing the tamping arm to swing left and right with its central pin as the fulcrum. This causes the tamping pick head mounted at the lower end of the tamping arm to generate a swinging forced vibration, which is then transmitted to the ballast, causing the ballast to vibrate and move in a more stable direction, thus increasing the compaction of the track bed.
[0004] The vibration frequency of the tamping device is usually set to 35Hz. It is directly driven by a quantitative hydraulic pump to drive a quantitative motor. The operating conditions generate a lot of noise. The tamping device maintains this vibration frequency throughout the entire operation process and has no frequency conversion function.
[0005] The information disclosed in the background section is only intended to enhance the understanding of the background of this application, and therefore may contain information that is not part of the prior art known to those skilled in the art. Summary of the Invention
[0006] This application provides a new type of variable frequency control valve group, its control method, hydraulic system, and tamping device.
[0007] A first aspect of this application provides a variable frequency control valve assembly for supplying controlled hydraulic fluid to a hydraulic motor; the variable frequency control valve assembly includes: Valve body; The branch assembly installed in the valve body includes a branch oil inlet, a branch oil outlet, a branch oil return port, and a parallel solenoid directional valve and a priority flow valve. The branch oil inlet is connected to the inlet of the solenoid directional valve and the inlet of the priority flow valve, the branch oil outlet is connected to the outlet of the solenoid directional valve and the outlet of the priority flow valve, and the branch oil return port is connected to the return oil of the priority flow valve.
[0008] A second aspect of this application provides a hydraulic system, including: The aforementioned frequency converter control valve assembly; The hydraulic pump's output port is connected to the branch inlet of the frequency converter control valve group; The hydraulic motor's input port is connected to the branch outlet port of the frequency converter control valve group.
[0009] A third aspect of this application provides a tamping device, including the aforementioned hydraulic system.
[0010] A fourth aspect of this application provides a control method for the above-mentioned variable frequency control valve group, comprising the following: When the normal operation command is triggered, the solenoid directional valve is in the open position, the priority flow valve T port has no bypass flow, the inlet and outlet flow of the frequency converter control valve group are consistent, and the flow corresponding to the normal operation condition of the hydraulic motor is maintained. When the low-frequency standby command is triggered, the solenoid directional valve is in the open circuit, the T port of the priority flow valve has bypass flow, and the outlet flow of the frequency converter control valve group is the set flow of the priority flow valve, which corresponds to the flow of the hydraulic motor in the low-frequency standby condition.
[0011] The embodiments of this application, by adopting the above technical solutions, have the following technical effects: The variable frequency control valve assembly integrates a parallel solenoid directional valve and a priority flow valve within the valve body, enabling it to automatically switch the oil supply mode according to operating conditions and provide matched controlled oil to the hydraulic motor. When the solenoid directional valve is turned on and there is no bypass flow at port T of the priority flow valve, the frequency converter control valve group outputs a large flow to meet the normal operation requirements of the hydraulic motor. When the solenoid directional valve is closed and there is bypass flow at port T of the priority flow valve, the frequency converter control valve group outputs a small flow to maintain the motor in a low-frequency standby state and avoid frequent start-stop.
[0012] This structure can achieve dual-mode flow switching between operation and standby without the need for an additional hydraulic pump or complex circuit. It has the advantages of energy saving, fast response, compact structure and high reliability, and is especially suitable for mobile hydraulic equipment that needs to be frequently started, stopped or in standby mode. Attached Figure Description
[0013] The accompanying drawings, which are included to provide a further understanding of this application and form part of this application, illustrate exemplary embodiments and are used to explain this application, but do not constitute an undue limitation of this application. In the drawings: Figure 1 This is a schematic diagram of the variable frequency control valve assembly of this application; Figure 2 This is a perspective view of the variable frequency control valve assembly of this application; Figure 3 This is a top view of the variable frequency control valve assembly of this application; Figure 4 This is a left view of the variable frequency control valve assembly of this application; Figure 5 This is a right view of the variable frequency control valve assembly of this application; Figure 6 This is a schematic diagram of the tamping device of this application.
[0014] Figure label: Oil inlet P11 for branch A, oil outlet P12 for branch A, solenoid directional valve A1 for branch A, priority flow valve A2 for branch A, oil inlet pressure test port M11 for branch A, oil outlet pressure test port M12 for branch A. Oil inlet P21 for branch B, oil outlet P22 for branch B, solenoid directional valve B3 for branch B, priority flow valve B4 for branch B, oil inlet pressure test port M21 for branch B, oil outlet pressure test port M22 for branch B. Branch return port T, valve body 5, Hydraulic pump A21, hydraulic motor A25, check valve A27 Hydraulic pump B22, hydraulic motor B26, check valve B28 Shuttle valve 23, relief valve 29, solenoid directional valve 210. Detailed Implementation
[0015] To make the technical solutions and advantages of the embodiments of this application clearer, the exemplary embodiments of this application will be described in further detail below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not an exhaustive list of all embodiments. It should be noted that, unless otherwise specified, the embodiments and features in the embodiments of this application can be combined with each other.
[0016] Example 1 like Figure 1 , Figure 2 , Figure 3 , Figure 4 and Figure 5 As shown in the embodiment of this application, the variable frequency control valve assembly is used to provide controlled hydraulic fluid to a hydraulic motor; the variable frequency control valve assembly includes: Valve body 5; The branch assembly installed in the valve body 5 includes a branch oil inlet, a branch oil outlet, a branch oil return port, and a parallel solenoid directional valve and a priority flow valve. The branch oil inlet is connected to the inlet of the solenoid directional valve and the inlet of the priority flow valve, the branch oil outlet is connected to the outlet of the solenoid directional valve and the outlet of the priority flow valve, and the branch oil return port is connected to the return oil of the priority flow valve.
[0017] When the electromagnetic directional valve is in the passage, there is no bypass flow at the T port of the priority flow valve, the flow rates at the inlet and outlet ports of the frequency conversion control valve group are consistent, and the priority flow valve does not play a flow regulation role, that is, the flow rate corresponding to the normal working condition of the hydraulic motor. When the electromagnetic reversing valve is in the open circuit state, the T port of the priority flow valve has bypass flow, and the outlet flow of the frequency conversion control valve group is the set flow of the priority flow valve, that is, the flow corresponding to the low-frequency standby condition of the hydraulic motor.
[0018] The variable frequency control valve assembly of this application, by integrating a branch assembly consisting of a parallel electromagnetic directional valve and a priority flow valve into the valve body, and in conjunction with a specific oil circuit connection relationship, achieves intelligent switching and precise matching of the oil supply flow of the hydraulic motor under different operating conditions, and has the following significant technical effects: By controlling the on / off states of the solenoid directional valve and the priority flow valve, efficient switching between two typical operating conditions can be achieved: When the solenoid directional valve is turned on and there is no bypass flow at port T of the priority flow valve, the flow rates at the inlet and outlet of the frequency converter control valve group remain consistent, providing the flow required for normal operation with high flow and high power, and meeting the high-speed operation requirements of the motor. When the solenoid directional valve is closed and there is bypass flow at port T of the priority flow valve, the outlet flow of the frequency converter control valve group is the set flow of the priority flow valve, providing low-flow, low-power low-frequency standby flow to maintain the low-speed operation of the hydraulic motor and avoid frequent start-stop.
[0019] This design effectively matches the actual needs of the motor in "operation" and "standby" states, significantly reducing energy consumption under no-load or light-load conditions.
[0020] Simplify the system structure and avoid redundant configurations of multiple hydraulic pumps or valves: Traditional solutions often require a separate low-flow pressure-maintaining hydraulic pump or an additional throttling circuit to achieve oil supply in standby conditions. This application, through a clever layout of two parallel valves within a single valve body, utilizes the inherent constant flow characteristics of the priority flow valve and the on / off characteristics of the solenoid directional valve to achieve dual-mode flow output with a single valve group, reducing the number of components, piping complexity, and system size, while improving reliability.
[0021] Ensuring system stability and rapid response capability under standby conditions: In low-frequency standby mode, the priority flow valve continuously provides a stable small flow rate, which can maintain the micro-motion of the hydraulic motor, system pressure, or lubrication circulation, avoiding cold start delay or lubrication interruption caused by complete shutdown; once a normal operation command is received, the solenoid directional valve quickly opens and immediately switches to the high flow rate mode, realizing a seamless and rapid transition from standby to operation, and improving the overall machine operation responsiveness.
[0022] Optimize oil circuit connections to ensure logical consistency and sealing reliability: The branch inlet connects to the inlets of both the solenoid directional valve and the priority flow valve, the branch outlet connects to the outlets of both, and the branch return port is directly connected to the return port of the priority flow valve, forming a clear and low-disturbance oil supply-return path. This layout not only conforms to hydraulic logic but also facilitates the integration of internal flow channels within the valve body, reduces leakage points, and improves manufacturing and maintenance convenience.
[0023] In summary, this variable frequency control valve group, through the parallel coordination of electromagnetic directional valves and priority flow valves and the adaptive switching mechanism of operating conditions, significantly improves the system's energy efficiency, response speed, and structural compactness while ensuring the high-performance operation of the hydraulic motor. It is particularly suitable for application scenarios in construction machinery that require frequent switching between working and standby states.
[0024] In practice, the priority flow valve is a priority flow valve with adjustable flow rate; The solenoid directional valve is a normally open type.
[0025] The priority flow valve is adjustable in flow rate, and the minimum flow rate value in standby mode can be flexibly set according to different working conditions. This allows the low-frequency operating speed of the hydraulic motor or the system pressure holding level to be optimized as needed, improving control accuracy and adaptability.
[0026] The electromagnetic reversing valve adopts a normally open structure, which automatically remains conductive in the event of power failure or failure, ensuring that the system is in normal operating oil supply mode by default, thus improving operational reliability. At the same time, in low-frequency standby conditions, only power is needed to cut off the main oil circuit and switch to the priority flow valve for oil supply, resulting in simple control logic and low energy consumption.
[0027] The combination of these two factors further enhances the overall performance of the valve assembly in terms of safety, energy efficiency, and adaptability to different operating conditions.
[0028] During implementation, such as Figure 1 , Figure 2 , Figure 3 , Figure 4 and Figure 5 As shown, when there are two hydraulic motors, the branch assembly includes branch assembly A and branch assembly B to provide controlled hydraulic fluid to the two hydraulic motors respectively; correspondingly: The A-branch assembly includes the A-branch oil inlet P11, the A-branch oil outlet P12, and the A-branch solenoid directional valve A1 and the A-branch priority flow valve A2 connected in parallel. The B branch assembly includes the B branch oil inlet P21, the B branch oil outlet P22, and the B branch solenoid directional valve B3 and the B branch priority flow valve B4 connected in parallel. Among them, the A branch component and the B branch component share the same branch return port T.
[0029] When two hydraulic motors are configured, the frequency converter control valve group has independent A branch components and B branch components, which can independently switch the flow mode and control the oil supply of the two hydraulic motors: Branch A, through the parallel connection of Branch A solenoid directional valve A1 and Branch A priority flow valve A2, enables the switching of the first hydraulic motor between normal operation (high flow) and low-frequency standby (low flow) conditions. Branch B controls the working state of the second hydraulic motor synchronously or asynchronously through the parallel B-branch solenoid directional valve B3 and B-branch priority flow valve B4. The two branches share the same branch return port T, which simplifies the internal flow channel design of the valve body, reduces external pipeline connections, and lowers the risk of leakage and installation space.
[0030] During implementation, such as Figure 1 , Figure 2 , Figure 3 , Figure 4 and Figure 5 As shown, the A branch component also includes: Connect the A-branch oil inlet P11 to the A-branch oil inlet pressure test port M11; Connect the oil outlet P12 of branch A to the oil outlet pressure test port M12 of branch A; Branch B components also include: Connect the oil inlet P21 of branch B to the oil inlet pressure test port M21 of branch B; Connect the oil outlet P22 of branch B to the oil outlet pressure test port M22 of branch B.
[0031] Two sets of inlet and outlet ports (A branch inlet P11, A branch outlet P12, B branch inlet P21, B branch outlet P22) can control two hydraulic motors simultaneously, or only one set of inlet and outlet ports P11, P12 or P21, P22 can be used to control one hydraulic motor. The specific selection can be made according to the actual number required.
[0032] Branch A assembly is equipped with branch A inlet pressure test port M11 and branch A outlet pressure test port M12, and branch B assembly is equipped with branch B inlet pressure test port M21 and branch B outlet pressure test port M22. This allows for real-time monitoring of the inlet and outlet pressures of each branch, facilitating: Accurately diagnose the hydraulic motor's oil supply status and load conditions; Quickly identify abnormalities such as blockages, leaks, or valve malfunctions; Pressure calibration and performance verification can be performed without disassembling the pipeline during the commissioning or maintenance phase.
[0033] This design significantly improves the system's observability, maintainability, and operational reliability, making it particularly suitable for applications requiring high synchronization or operational stability of the dual hydraulic motors.
[0034] Example 2 like Figure 6 As shown, the hydraulic system of this application embodiment includes: Variable frequency control valve assembly of Example 1; The hydraulic pump's output port is connected to the branch inlet of the frequency converter control valve group; The hydraulic motor's input port is connected to the branch outlet port of the frequency converter control valve group.
[0035] The hydraulic system of this application embodiment integrates a variable frequency control valve group, a hydraulic pump, and a hydraulic motor, forming a high-efficiency, intelligent, and condition-adaptive hydraulic drive system, which has the following technical effects: The hydraulic pump outputs oil through a variable frequency control valve group for precise distribution. It can automatically switch between high flow (normal tamping) or low flow (standby / low frequency operation) modes according to the operation requirements, thus avoiding ineffective energy consumption. The variable frequency control valve group enables the hydraulic motor to start and stop quickly, adjust speed smoothly and maintain pressure reliably, thereby improving the responsiveness and stability of the tamping action; The system has a compact structure, high oil circuit integration, and a pressure testing port design, which facilitates on-site debugging and fault diagnosis. In railway line maintenance operations, it can meet the power requirements of high-intensity tamping and reduce power consumption and noise during intervals, significantly improving energy efficiency and equipment reliability.
[0036] This hydraulic system is particularly suitable for large road maintenance machinery that requires frequent start-stop, long-term standby, or high operational precision.
[0037] By adding a hydraulic control valve group between the hydraulic pump and the hydraulic motor, the hydraulic motor is controlled to operate at the normal operating frequency during the tamping process; and to switch to low-frequency standby mode during non-tamping processes. This achieves energy saving and noise reduction, ensures the response speed when switching to normal operating power, and reduces hydraulic shock compared to the scheme of directly controlling the start and stop of the tamping device's vibration motor, thus extending the service life of the device.
[0038] During implementation, such as Figure 6 As shown, the hydraulic pumps are two, namely hydraulic pump A21 and hydraulic pump B22, and correspondingly, the hydraulic motors are two, namely hydraulic motor A25 and hydraulic motor B26; Correspondingly: The output port of hydraulic pump A21 is connected to the oil inlet port P11 of branch A, and the input port of hydraulic motor A is connected to the oil outlet port P12 of branch A. The output port of hydraulic pump B22 is connected to the oil inlet port P21 of branch B, and the input port of hydraulic motor B is connected to the oil outlet port P22 of branch B.
[0039] The hydraulic system adopts a structure in which two hydraulic pumps (Hydraulic pump A21, Hydraulic pump B22) and two hydraulic motors (Hydraulic motor A25, Hydraulic motor B26) are connected respectively. With the help of the A and B branch components in the frequency converter control valve group, the two hydraulic drive circuits can be completely independently controlled and powered, which has the following technical effects: Power decoupling, no interference between them: The A and B hydraulic systems each have independent pump sources and control branches, avoiding mutual influence of flow / pressure due to load differences or different working conditions, and ensuring stable operation of the two hydraulic motors; On-demand energy supply and high efficiency: Each pump can independently switch between high flow rate and low flow rate modes according to the actual working conditions (such as tamping on one side and standing by on the other), avoiding the energy waste of "one pump running and all pumps running" in a single pump system; Enhance system redundancy and reliability: If any pump or motor fails, the other circuit can still maintain basic functions, enhancing the equipment's fault tolerance in field operation environments; It facilitates synchronous or asynchronous operation control: it can achieve synchronous tamping with dual motors, or independently adjust the movement of both sides to adapt to uneven tracks or different operation requirements.
[0040] This dual-pump, dual-motor independent drive structure significantly improves the control flexibility, energy efficiency, and operational adaptability of the tamping device, making it particularly suitable for high-precision, high-reliability railway line maintenance scenarios.
[0041] The working principle of the hydraulic system of this invention is as follows: Normal operating conditions: Solenoid directional valve A1 in branch A and solenoid directional valve B3 in branch B are de-energized and connected; priority flow valves A2 in branch A and B4 in branch B are not working; hydraulic pumps A21 and B22 output all their flow to drive hydraulic motors A25 and B26 of the tamping device respectively; hydraulic motors A25 and B26 operate at the frequency of normal operating conditions.
[0042] Low-frequency standby mode: When the solenoid directional valves A1 and B3 of branch A are energized and cut off, the priority flow valves A2 and B4 of branch A and B start working. The hydraulic pumps A21 and B22 drive the hydraulic motors A25 and B26 of the tamping device respectively through the priority flow valves A2 and B4 of branch A and branch B, thus entering the low-frequency standby mode.
[0043] During implementation, such as Figure 6 As shown, the hydraulic system also includes: A one-way valve A27 is connected in parallel with the hydraulic motor A25; A one-way valve B28 is connected in parallel with the hydraulic motor B26.
[0044] The hydraulic system has check valves A27 and B28 connected in parallel on the oil lines of hydraulic motors A25 and B26, respectively, which has the following technical effects: When the vibratory motor of the tamping device switches from normal driving mode to low-frequency standby mode or from running mode to stopped mode, the motor speed cannot be switched instantaneously due to inertia. Oil can be replenished from the motor outlet through a one-way valve.
[0045] During implementation, such as Figure 6 As shown, the hydraulic system also includes a shuttle valve 23, a relief valve 29, and a solenoid directional valve 210; The shuttle valve 23 has two inlets connected to the oil inlet P11 of branch A and the oil inlet P21 of branch B, respectively. The outlet of the shuttle valve 23 is connected to the inlet of the overflow valve 29. The oil control port of the overflow valve 29 is connected to the solenoid directional valve 210.
[0046] The safety pressure of the two circuits corresponding to hydraulic pumps A21 and B22 is adjusted by the relief valve 29. The control port of the relief valve 29 is connected to the solenoid directional valve 210. When the solenoid directional valve 210 is de-energized, the system is unloaded; when energized, pressure is built up.
[0047] During implementation, the tamping device also includes: Control unit, used for: When the normal operation command is triggered, the electromagnetic directional valve is in the passage, the priority flow valve T port has no bypass flow, and the flow rates of the inlet and outlet of the frequency conversion control valve group are consistent, which is the flow rate corresponding to the normal operation condition of the hydraulic motor. When the low-frequency standby command is triggered, the electromagnetic directional valve is in the open circuit, the T port of the priority flow valve has bypass flow, and the outlet flow of the frequency conversion control valve group is the set flow of the priority flow valve, that is, the flow corresponding to the low-frequency standby condition of the hydraulic motor.
[0048] The tamping device is equipped with a control unit, which can intelligently adjust the working status of the electromagnetic directional valve and the priority flow valve in the frequency conversion control valve group according to the operation instructions, so as to realize the automatic switching of the hydraulic motor oil supply mode. When a normal operation command is received, the control unit activates the solenoid directional valve and closes the priority flow valve, outputting a large flow of oil to meet the high-intensity, high-response operation requirements of the tamping device. When a low-frequency standby command is received, the control unit closes the solenoid directional valve and opens the priority flow valve, providing only a small flow to maintain the motor's micro-motion or the system's pressure, significantly reducing energy consumption and noise.
[0049] This control strategy enables on-demand oil supply, intelligent switching, and energy-saving operation, avoiding prolonged full-load idling of the hydraulic system while ensuring rapid response from standby to operation, thus improving the automation level, energy efficiency, and operational reliability of the tamping device.
[0050] Example 3 The control method for the variable frequency control valve group in this application is a control method for the variable frequency control valve group of Embodiment 1, including: When the normal operation command is triggered, the solenoid directional valve is in the open position, the priority flow valve T port has no bypass flow, the inlet and outlet flow of the frequency converter control valve group are consistent, and the flow corresponding to the normal operation condition of the hydraulic motor is maintained. When the low-frequency standby command is triggered, the solenoid directional valve is in the open circuit, the T port of the priority flow valve has bypass flow, and the outlet flow of the frequency converter control valve group is the set flow of the priority flow valve, which corresponds to the flow of the hydraulic motor in the low-frequency standby condition.
[0051] Although preferred embodiments of this application have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments as well as all changes and modifications falling within the scope of this application.
[0052] Obviously, those skilled in the art can make various modifications and variations to this application without departing from the spirit and scope of this application. Therefore, if such modifications and variations fall within the scope of the claims of this application and their equivalents, this application also intends to include such modifications and variations.
Claims
1. A variable frequency control valve bank characterized by, Used to supply controlled hydraulic fluid to a hydraulic motor; the frequency converter control valve assembly includes: Valve body (5); The branch assembly installed in the valve body (5) includes a branch oil inlet, a branch oil outlet, a branch oil return port, and a parallel solenoid directional valve and a priority flow valve. The branch oil inlet is connected to the inlet of the solenoid directional valve and the inlet of the priority flow valve, the branch oil outlet is connected to the outlet of the solenoid directional valve and the outlet of the priority flow valve, and the branch oil return port is connected to the return oil of the priority flow valve.
2. The variable frequency control valve assembly according to claim 1, characterized in that, When the electromagnetic directional valve is in the passage, there is no bypass flow at the T port of the priority flow valve, the flow rates at the inlet and outlet ports of the frequency conversion control valve group are consistent, the priority flow valve does not play a flow regulation role, and the flow rate corresponding to the normal working condition of the hydraulic motor is as follows. When the electromagnetic reversing valve is in the open circuit state, the T port of the priority flow valve has bypass flow, the outlet flow of the frequency conversion control valve group is the set flow of the priority flow valve, and the flow corresponding to the low-frequency standby condition of the hydraulic motor.
3. The variable frequency control valve assembly according to any one of claims 1 to 2, characterized in that, When there are two hydraulic motors, the branch assembly includes branch assembly A and branch assembly B to provide controlled hydraulic fluid to each of the two hydraulic motors; correspondingly: The A branch assembly includes the A branch inlet (P11), the A branch outlet (P12), and the A branch solenoid directional valve (A1) and the A branch priority flow valve (A2) connected in parallel. The B branch assembly includes the A branch inlet (P21), the B branch outlet (P22), and the B branch solenoid directional valve (B3) and the B branch priority flow valve (B4) connected in parallel. Among them, the A branch assembly and the B branch assembly share the same branch return port (T).
4. The variable frequency control valve assembly according to claim 3, characterized in that, Branch A component also includes: Connect the A-branch oil inlet (P11) to the A-branch oil inlet pressure test port (M11). Connect the oil outlet of branch A (P12) to the oil pressure test port (M12) of branch A. Branch B components also include: Connect the oil inlet of branch B (P21) to the oil inlet pressure test port (M21). Connect the oil outlet of branch B (P22) to the oil outlet pressure test port (M22) of branch B; The priority flow valve is a priority flow valve with adjustable flow rate; The solenoid directional valve is a normally open type.
5. A hydraulic system, characterized in that, include: The variable frequency control valve assembly according to any one of claims 1 to 4; The hydraulic pump's output port is connected to the branch inlet of the frequency converter control valve group; The hydraulic motor's input port is connected to the branch outlet port of the frequency converter control valve group.
6. The hydraulic system according to claim 5, characterized in that, The hydraulic pumps consist of two pumps, namely hydraulic pump A (A21) and hydraulic pump B (B22), and correspondingly, the hydraulic motors consist of two pumps, namely hydraulic motor A (A25) and hydraulic motor B (B26). The output port of hydraulic pump A (A21) is connected to the oil inlet port (P11) of branch A, and the input port of hydraulic motor A is connected to the oil outlet port (P12) of branch A. The output port of hydraulic pump B (B22) is connected to the oil inlet port (P21) of branch B, and the input port of hydraulic motor B is connected to the oil outlet port (P22) of branch B. Also includes: A one-way valve (A27) is connected in parallel with the hydraulic motor A (A25); A check valve (B28) connected in parallel with the hydraulic motor (B26).
7. The hydraulic system according to claim 6, characterized in that, It also includes a shuttle valve (23), an overflow valve (29), and a solenoid directional valve (210). The shuttle valve (23) has its two inlets connected to the oil inlet of branch A (P11) and branch B (P21) respectively. The outlet of the shuttle valve (23) is connected to the inlet of the overflow valve (29). The oil control port of the overflow valve (29) is connected to the solenoid directional valve (210).
8. The hydraulic system according to claim 7, characterized in that, Also includes: Control unit, used for: When the normal operation command is triggered, the electromagnetic directional valve is in the passage, the priority flow valve T port has no bypass flow, and the flow rates of the inlet and outlet of the frequency conversion control valve group are consistent, which is the flow rate corresponding to the normal operation condition of the hydraulic motor. When the low-frequency standby command is triggered, the electromagnetic directional valve is in the open circuit, the T port of the priority flow valve has bypass flow, and the outlet flow of the frequency conversion control valve group is the set flow of the priority flow valve, that is, the flow corresponding to the low-frequency standby condition of the hydraulic motor.
9. A tamping device, characterized in that, include: The tamping device frame and the hydraulic system according to any one of claims 5-8 mounted on the frame.
10. A control method for a variable frequency control valve group according to any one of claims 1 to 4, characterized in that, include: When the normal operation command is triggered, the solenoid directional valve is in the open position, the priority flow valve T port has no bypass flow, the inlet and outlet flow of the frequency converter control valve group are consistent, and the flow corresponding to the normal operation condition of the hydraulic motor is maintained. When the low-frequency standby command is triggered, the solenoid directional valve is in the open circuit, the T port of the priority flow valve has bypass flow, and the outlet flow of the frequency converter control valve group is the set flow of the priority flow valve, which corresponds to the flow of the hydraulic motor in the low-frequency standby condition.