Rotary control system and method and arm type aerial work platform

Abstract

The invention discloses a rotation control system and method and an arm type aerial work platform, and relates to the technical field of engineering machinery. In the rotation control system, an oil outlet of a main pump communicates with an oil inlet P of a proportional flow valve, an oil port A1 and an oil port B1 of the proportional flow valve communicate with an oil port V1 and an oil port V2 correspondingly, and an oil return port T of the proportional flow valve communicates with an oil tank; the oil port C1 is communicated with an oil port A2 of the motor, and the oil port C2 is communicated with an oil port B2 of the motor; the oil port V1 is communicated with the oil port C1 and a first inlet of the first shuttle valve through the first balance valve; the oil port V2 is communicated with the oil port C2 and a second inlet of the first shuttle valve through a second balance valve; an outlet of the first shuttle valve is communicated with an inlet of the proportional overflow valve, and an outlet of the proportional overflow valve is communicated with the oil port V1 and the oil port V2. The rotation control system solves the problems of pressure impact and vibration in the starting and braking process of the system.

Description

Technical Field

[0001] This application relates to the field of engineering machinery technology, and in particular to a slewing control system, method and boom-type aerial work platform. Background Technology

[0002] The slewing control system of a boom-type aerial work platform is the core actuator for adjusting the platform's orientation, and its control performance directly affects the overall operating efficiency and safety.

[0003] Currently, the common practice in this field is to use flow control strategies to regulate slewing speed, that is, to control the speed of the slewing motor by controlling the flow of hydraulic oil in the control system. However, the slewing control system of boom lifts has a significant large inertia characteristic. When the boom is fully extended horizontally, the system's moment of inertia reaches its maximum. At this time, during the start-up of slewing, the hydraulic system pressure is prone to overshoot; while during the braking of slewing, due to inertia, the slewing motor is prone to swaying. Both of these pressure overshoots and motor swaying will generate severe pressure shocks, causing vibrations in the boom structure, which not only reduces work efficiency but may also threaten the personal safety of personnel working at height.

[0004] Therefore, how to effectively suppress pressure shocks and vibrations during the start-up and braking processes of the slewing control system has become a key technical problem that urgently needs to be solved in the field of boom aerial work platform control technology. Summary of the Invention

[0005] The purpose of this application is to provide a slewing control system, method, and boom-type aerial work platform that solves the problems of pressure shock and vibration during system start-up and braking.

[0006] To achieve the above objectives, this application provides a slewing control system for boom-type aerial work platforms, including a main pump, a proportional flow valve, a balance valve assembly, and a motor.

[0007] The balancing valve assembly includes a first balancing valve, a second balancing valve, a first shuttle valve, and a proportional relief valve. The balancing valve assembly has oil ports V1, V2, C1, and C2.

[0008] The main pump's outlet is connected to the proportional flow valve's inlet P. The proportional flow valve's ports A1 and B1 are connected to ports V1 and V2, respectively. The proportional flow valve's return port T is connected to the oil tank.

[0009] Oil port C1 is connected to oil port A2 of the motor, and oil port C2 is connected to oil port B2 of the motor.

[0010] Oil port V1 is connected to oil port C1 and the first inlet of the first shuttle valve through the first balance valve;

[0011] Oil port V2 is connected to oil port C2 and the second inlet of the first shuttle valve through the second balance valve;

[0012] The outlet of the first shuttle valve is connected to the inlet of the proportional relief valve, and the outlet of the proportional relief valve is connected to oil port V1 and oil port V2.

[0013] In some embodiments, the system further includes a controller and an operating handle. The controller is signal-connected to the proportional flow valve and the proportional relief valve, and the operating handle is signal-connected to the controller. The operating handle is used to feed back control commands to the controller so that the controller controls the proportional flow valve and the proportional relief valve to operate.

[0014] In some embodiments, the balance valve assembly further includes a first throttling element and a second throttling element, wherein the inlet of the first throttling element is connected to the oil port V1 and the outlet of the first throttling element is connected to the pilot port of the second balance valve; the inlet of the second throttling element is connected to the oil port V2 and the outlet of the second throttling element is connected to the pilot port of the first balance valve.

[0015] In some embodiments, the balance valve assembly further includes a second shuttle valve, and the balance valve assembly also has an oil port C3. The first inlet and the second inlet of the second shuttle valve are respectively connected to oil ports V1 and V2, and the outlet of the second shuttle valve is connected to the braking oil port C of the motor's reduction mechanism through oil port C3.

[0016] In some embodiments, the proportional flow valve is a three-position four-way proportional flow valve.

[0017] In some embodiments, the balancing valve assembly further includes a first check valve and a second check valve, the outlet of the proportional relief valve is connected to the inlet of the first check valve and the inlet of the second check valve, and the outlet of the first check valve and the outlet of the second check valve are connected to oil port V1 and oil port V2, respectively.

[0018] This application provides a slewing control method, applied to the slewing control system described in the above embodiments, including:

[0019] In the initial stage of starting the slewing control system, the control current of the proportional flow valve and the proportional relief valve is controlled so that the pressure of oil port V1 and the pressure of oil port B2 reach the slewing conditions of the motor, and the motor enters the uniform acceleration stage after it starts to slew.

[0020] In the initial braking phase of the slewing control system, the control current of the proportional flow valve and the proportional relief valve is controlled so that the pressure of oil port V1 and the pressure of oil port B2 reach the locking condition of the second balance valve, and the pressure of oil port B2 is reduced after the second balance valve is locked.

[0021] In some embodiments, during the initial startup phase of the slewing control system, the step of controlling the control current of the proportional flow valve and the proportional relief valve to ensure that the pressure at port V1 and the pressure at port B2 meet the slewing conditions of the motor, and then entering the uniform acceleration phase after the motor begins to slew, includes:

[0022] In the initial first stage of starting the slewing control system, the control current of the proportional flow valve and the proportional relief valve is increased so that the proportional flow valve operates at a preset minimum operating current and the motor begins to rotate.

[0023] In the initial second stage of the slewing control system startup, the control current of the proportional flow valve and the proportional relief valve is continuously increased to enable the motor to enter the uniform acceleration slewing stage.

[0024] In some embodiments, during the initial braking phase of the slewing control system, the step of controlling the control current of the proportional flow valve and the proportional relief valve to make the pressures at port V1 and port B2 reach the locking condition of the second balance valve, and then reducing the pressure at port B2 after the second balance valve locks out, includes:

[0025] In the initial first stage of braking of the slewing control system, the control current of the proportional flow valve and the proportional relief valve is reduced so that the pressure of oil port V1 and the pressure of oil port B2 reach the locking condition of the second balance valve.

[0026] In the initial second stage of braking of the slewing control system, the pressure at port B2 is reduced by continuing to decrease the control current of the proportional relief valve.

[0027] This application also provides a boom-type aerial work platform, including the slewing control system of any of the above.

[0028] Compared to the aforementioned background technology, the slewing control system provided in this application embodiment is applied to a boom-type aerial work platform, including a main pump, a proportional flow valve, a balance valve assembly, and a motor. The balance valve assembly includes a first balance valve, a second balance valve, a first shuttle valve, and a proportional relief valve. The balance valve assembly has ports V1, V2, C1, and C2. The outlet of the main pump is connected to the inlet P of the proportional flow valve. Ports A1 and B1 of the proportional flow valve are connected to ports V1 and V2, respectively. The return port T of the proportional flow valve is connected to the oil tank. Port C1 is connected to port A2 of the motor, and port C2 is connected to port B2 of the motor. Port V1 is connected to port C1 and the first inlet of the first shuttle valve via the first balance valve. Port V2 is connected to port C2 and the second inlet of the first shuttle valve via the second balance valve. The outlet of the first shuttle valve is connected to the inlet of the proportional relief valve, and the outlet of the proportional relief valve is connected to ports V1 and V2.

[0029] This application also provides a slewing control method applied to the aforementioned slewing control system. The control method includes: in the initial startup phase of the slewing control system, controlling the control current of the proportional flow valve and the proportional relief valve to make the pressure of oil port V1 and the pressure of oil port B2 reach the slewing conditions of the motor, and entering a uniform acceleration phase after the motor starts to slew; in the initial braking phase of the slewing control system, controlling the control current of the proportional flow valve and the proportional relief valve to make the pressure of oil port V1 and the pressure of oil port B2 reach the locking conditions of the second balance valve, and reducing the pressure of oil port B2 after the second balance valve is locked.

[0030] The main benefits of this slewing control system configuration include:

[0031] Firstly, in the initial startup phase of the slewing control system, the control current of the proportional flow valve and proportional relief valve is coordinated to gradually bring the pressure at port V1 and port B2 up to the motor's slewing condition. After the motor begins to slew, it enters a uniform acceleration phase, thus achieving a smooth motor start-up. Compared to traditional pure flow regulation, this gradual flow and pressure coordination decouples the system pressure and flow during the slewing startup process, effectively avoiding the pressure overshoot phenomenon caused by instantaneous pressure build-up in traditional startup methods. This significantly reduces the mechanical shock and vibration of the boom at startup, improving the operational comfort and safety of the boom-type aerial work platform, while also reducing wear on hydraulic components and extending the system's service life.

[0032] Secondly, during the initial braking phase of the slewing control system, the control current of the proportional flow valve and the proportional relief valve are coordinated to ensure that the pressures at port V1 and port B2 first reach the locking condition of the second balance valve. Once the second balance valve is reliably locked, the pressure at port B2 is reduced through the first shuttle valve and the proportional relief valve. This braking control strategy effectively prevents boom vibration caused by pressure surges at motor port B2 during braking, ensuring the smoothness and reliability of the braking process, avoiding impact damage to the boom structure caused by sudden pressure changes, and improving the stability and safety of the aerial work platform under braking conditions. Attached Figure Description

[0033] To more clearly illustrate the technical solutions in the embodiments of this application or related technologies, the drawings used in the description of the embodiments or related technologies will be briefly introduced below. Obviously, the drawings described below are only embodiments of this application. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0034] Figure 1 This is a schematic diagram of a rotary control system in the prior art.

[0035] Figure 2 for Figure 1 The diagram shows the control logic during the system startup phase.

[0036] Figure 3 for Figure 1 The diagram shows the control logic for the braking phase of the system.

[0037] Figure 4 This is a schematic diagram of the slewing control system in an embodiment of this application.

[0038] Figure 5 This is a flowchart of the slewing control method in the embodiments of this application.

[0039] Figure 6 for Figure 4 The diagram shows the control logic during the system startup phase.

[0040] Figure 7 for Figure 4 The diagram shows the control logic for the braking phase of the system.

[0041] in:

[0042] 1-Main pump;

[0043] 2-Proportional flow valve;

[0044] 3-Balance valve assembly; 31-First balance valve; 32-Second balance valve; 33-First shuttle valve; 34-Proportional relief valve; 35-First throttling element; 36-Second throttling element; 37-Second shuttle valve; 38-First check valve; 39-Second check valve;

[0045] 4-Motor;

[0046] 5- Gear reducer;

[0047] 6-Controller;

[0048] 7-Operating handle. Detailed Implementation

[0049] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0050] To enable those skilled in the art to better understand the present application, the present application will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0051] like Figure 4 As shown in the embodiment of this application, the slewing control system is applied to a boom-type aerial work platform and includes a main pump 1, a proportional flow valve 2, a balance valve group 3, and a motor 4.

[0052] The balance valve assembly 3 includes a first balance valve 31, a second balance valve 32, a first shuttle valve 33, and a proportional relief valve 34. The balance valve assembly 3 has oil ports V1, V2, C1, and C2.

[0053] The proportional flow valve 2 is a three-position four-way proportional flow valve. The oil outlet of the main pump 1 is connected to the oil inlet P of the proportional flow valve 2. The oil ports A1 and B1 of the proportional flow valve 2 are connected to the oil ports V1 and V2 respectively. The oil return port T of the proportional flow valve 2 is connected to the oil tank.

[0054] Oil port C1 is connected to oil port A2 of motor 4, and oil port C2 is connected to oil port B2 of motor 4.

[0055] Oil port V1 is connected to oil port C1 and the first inlet of the first shuttle valve 33 through the first balance valve 31; oil port V2 is connected to oil port C2 and the second inlet of the first shuttle valve 33 through the second balance valve 32.

[0056] The outlet of the first shuttle valve 33 is connected to the inlet of the proportional relief valve 34, and the outlet of the proportional relief valve 34 is connected to oil port V1 and oil port V2.

[0057] Set it up like this:

[0058] In the initial stage of the slewing control system startup, the control current of proportional flow valve 2 and proportional relief valve 34 is coordinated to gradually bring the pressure at port V1 and port B2 up to the slewing conditions of motor 4. After motor 4 begins to slew, it enters a uniform acceleration stage, thus achieving a smooth start-up of motor 4. Compared to the traditional pure flow regulation method, this gradual flow and pressure coordinated regulation method decouples the system pressure and flow during the slewing startup process, effectively avoiding the pressure overshoot phenomenon caused by instantaneous pressure build-up in the traditional startup method. This significantly reduces the mechanical shock and vibration of the boom at the moment of startup, improves the operating comfort and safety of the boom aerial work platform, and reduces the wear of hydraulic components, extending the service life of the system.

[0059] In the initial braking phase of the slewing control system, the control current of the proportional flow valve 2 and the proportional relief valve 34 is coordinated to ensure that the pressures at port V1 and port B2 first reach the locking condition of the second balance valve 32. After the second balance valve 32 is reliably locked, the pressure at port B2 is reduced through the first shuttle valve 33 and the proportional relief valve 34. This braking control strategy effectively prevents boom vibration caused by pressure surges at port B2 of the motor 4 during braking, ensuring the smoothness and reliability of the braking process, avoiding impact damage to the boom structure caused by sudden pressure changes, and improving the stability and safety of the aerial work platform under braking conditions.

[0060] Furthermore, the balance valve assembly 3 also includes a first check valve 38 and a second check valve 39. The outlet of the proportional relief valve 34 is connected to the inlet of the first check valve 38 and the inlet of the second check valve 39. The outlet of the first check valve 38 and the outlet of the second check valve 39 are respectively connected to oil port V1 and oil port V2.

[0061] In this way, by setting a first check valve 38 and a second check valve 39 between the outlet (also called the return port) of the proportional relief valve 34 and ports V1 and V2 respectively, directional flow control of the pressurized oil is achieved. Depending on the operating conditions, the outlet of the proportional relief valve 34 can freely return oil to ports V1 and V2 through the first check valve 38 and the second check valve 39 respectively.

[0062] Specifically, during the initial stage of system startup, the control current of the proportional relief valve 34 is increased to increase the pressure at port V1 or port V2. The first check valve 38 and the second check valve 39 effectively prevent reverse flow of pressurized oil, ensuring the accuracy and unidirectionality of pressure establishment during the initial startup stage. This further improves the response speed and stability of pressure regulation, avoids pressure fluctuations caused by oil backflow, and thus more effectively suppresses boom vibration. In addition, the configuration of the first check valve 38 and the second check valve 39 allows the control current of the proportional relief valve 34 to be reduced during the initial braking stage, thereby reducing the pressure at port C2 or port B2. The output control pressure can be transmitted unidirectionally and quickly to the corresponding port (V1 or V2), preventing reverse flow of oil or pressure crosstalk during the pressure reduction process at port B2. This ensures a smooth transition during the braking process and further eliminates the risk of boom vibration caused by pressure coupling.

[0063] In some embodiments, the balance valve assembly 3 further includes a first throttling element 35 and a second throttling element 36. The inlet of the first throttling element 35 is connected to the oil port V1, and the outlet of the first throttling element 35 is connected to the pilot port of the second balance valve 32. The inlet of the second throttling element 36 is connected to the oil port V2, and the outlet of the second throttling element 36 is connected to the pilot port of the first balance valve 31.

[0064] Taking the proportional flow valve 2 operating in the left position as an example, during rotary start-up, the pressure oil output from the main pump 1 flows from the inlet P of the proportional flow valve 2 to port A1, then through port V1 of the balance valve assembly 3 and from the bypass check valve side of the first balance valve 31 into port A2 of the motor 4. Simultaneously, port V1 of the balance valve assembly 3 flows through the first throttling element 35 to the pilot port of the second balance valve 32, thereby opening the main valve core side of the second balance valve 32. This allows the pressure oil at port B2 of the motor 4 to flow through the main valve core side of the second balance valve 32 to port V2, and finally from port B1 of the proportional flow valve 2 to the return port T, returning to the oil tank, thus realizing the hydraulic circuit for forward rotation of the system. Conversely, if the proportional flow valve 2 is switched to the right position, the flow direction of the hydraulic circuit is reversed, realizing the hydraulic circuit for reverse rotation of the system.

[0065] In some embodiments, the balance valve assembly 3 further includes a second shuttle valve 37, and the balance valve assembly 3 also has an oil port C3. The first inlet and the second inlet of the second shuttle valve 37 are respectively connected to oil ports V1 and V2, and the outlet of the second shuttle valve 37 is connected to the brake oil port C of the reducer 5 of the motor 4 through oil port C3.

[0066] After both the proportional flow valve 2 and the proportional relief valve 34 are opened, the high-pressure oil from port V1 or port V2 is selected by the second shuttle valve 37 and flows through port C3 to the brake port C of the reducer 5 of the motor 4, thereby releasing the brake of the reducer 5 of the motor 4 so that the motor 4 can rotate.

[0067] In some embodiments, the system further includes a controller 6 and an operating handle 7. The controller 6 is signal-connected to the proportional flow valve 2 and the proportional relief valve 34, and the operating handle 7 is signal-connected to the controller 6. The operating handle 7 is used to feed back control commands to the controller 6 so that the controller 6 controls the proportional flow valve 2 and the proportional relief valve 34 to work.

[0068] Specifically, controller 6 is configured as follows:

[0069] In the initial stage of starting the slewing control system, the control current of the proportional flow valve 2 and the proportional relief valve 34 is controlled so that the pressure of oil port V1 and the pressure of oil port B2 reach the slewing conditions of motor 4, and after motor 4 starts to slew, it enters the uniform acceleration stage.

[0070] In the initial braking phase of the slewing control system, the control current of the proportional flow valve 2 and the proportional relief valve 34 is controlled so that the pressure of oil port V1 and the pressure of oil port B2 reach the locking condition of the second balance valve 32, and the pressure of oil port B2 is reduced after the second balance valve 32 is locked.

[0071] Specifically, in the initial first stage of the slewing control system startup, the control current of proportional flow valve 2 and proportional relief valve 34 is increased to make proportional flow valve 2 operate at a preset minimum operating current, and motor 4 begins to rotate. In the initial second stage of the slewing control system startup, the control current of proportional flow valve 2 and proportional relief valve 34 is further increased to make motor 4 enter a uniform acceleration slewing stage. In the initial first stage of the slewing control system braking, the control current of proportional flow valve 2 and proportional relief valve 34 is decreased to make the pressure at port V1 and port B2 reach the locking condition of the second balance valve 32. In the initial second stage of the slewing control system braking, the control current of proportional relief valve 34 is further decreased to reduce the pressure at port B2.

[0072] like Figure 5 As shown, this application provides a slewing control method applied to the slewing control system described in the above embodiments. The control method includes:

[0073] In the initial stage of starting the slewing control system, the control current of the proportional flow valve 2 and the proportional relief valve 34 is controlled (increased) so that the pressure of oil port V1 and the pressure of oil port B2 reach the slewing conditions of motor 4, and the motor 4 enters the uniform acceleration stage after it starts to slew.

[0074] In the initial braking phase of the slewing control system, the control current of the proportional flow valve 2 and the proportional relief valve 34 is controlled (reduced) so that the pressure of oil port V1 and the pressure of oil port B2 reach the locking condition of the second balance valve 32, and the pressure of oil port B2 is reduced after the second balance valve 32 is locked.

[0075] In some embodiments, during the initial startup phase of the slewing control system, the steps of controlling the control current of the proportional flow valve 2 and the proportional relief valve 34 to ensure that the pressures at oil port V1 and oil port B2 meet the slewing conditions of the motor 4, and then entering the uniform acceleration phase after the motor 4 begins to rotate, include:

[0076] In the initial first stage of the slewing control system startup, the control current of the proportional flow valve 2 and the proportional relief valve 34 is increased so that the proportional flow valve 2 operates at a preset minimum operating current and the motor 4 starts to rotate.

[0077] In the initial second stage of the slewing control system startup, the control current of the proportional flow valve 2 and the proportional relief valve 34 is continuously increased to enable the motor 4 to enter the uniform acceleration slewing stage.

[0078] During the slewing start-up phase:

[0079] In such Figure 1 and Figure 2In the existing control scheme shown in the industry, when current is detected on the operating handle 7, the proportional flow valve 2 increases the control current. Taking the proportional flow valve 2 in the left position as an example, during the rotary start, the pressure oil output by the main pump 1 flows from the inlet P of the proportional flow valve 2 to the outlet A1, and then through the outlet V1 of the balance valve group 3 to the outlet A2 of the motor 4 via the bypass check valve side of the first balance valve 31. At this time, due to the low system pressure, the system pressure has not reached the brake release pressure of the reducer 5 and the opening pressure of the second balance valve 32. Under the dual action of the brake of the reducer 5 and the load holding function of the second balance valve 32, the motor 4 cannot rotate, and the system pressure begins to rise. Ignoring the system return oil back pressure, the motor 4 starts to rotate if and only if the system pressure is greater than the brake release pressure of the reducer 5 and the system pressure is greater than the opening pressure of the second balance valve 32. Specifically, the following two conditions are met simultaneously:

[0080]

[0081] in, V1 Pz is the pressure at port V1 of the balance valve assembly 3, and Pz is the brake release pressure of the reducer 5 of the motor 4. mb The pressure at port B2 of motor 4, i is the pilot ratio of the second balance valve 32, and P is the pressure at port B2 of motor 4. 1-2 The set pressure for the second balancing valve 32.

[0082] When motor 4 starts rotating, at the instant the second balance valve 32 opens, the system pressure overshoots due to the large rotational inertia of the boom, causing the boom to vibrate.

[0083] Therefore, such as Figure 4 As shown, this application addresses the shortcomings of traditional designs during the slewing start-up phase by adding a first shuttle valve 33, a proportional relief valve 34, a first check valve 38, and a second check valve 39 to the balance valve assembly 3. The two inlets of the first shuttle valve 33 are connected to oil ports C1 and C2, respectively. The outlet of the first shuttle valve 33 is connected to the inlet of the proportional relief valve 34, and the outlet of the proportional relief valve 34 is connected to the first check valve 38 and the second check valve 39. Depending on the operating conditions, the outlet of the proportional relief valve 34 can freely return oil to oil ports V1 and V2 via the first check valve 38 and the second check valve 39, respectively, thus solving the problem of traditional designs during the slewing start-up phase. Specifically:

[0084] During the slewing start-up phase:

[0085] like Figure 6 As shown, during the initial startup phase, after detecting an output from the operating handle 7, the proportional flow valve 2 begins to operate with the minimum working current. Simultaneously, the proportional relief valve 34 increases the control current (its opening decreases) to ensure the system pressure meets the condition for the rotary motor 4 to begin rotating.

[0086]

[0087] After that, the proportional flow valve 2 begins to increase the current, while the proportional relief valve 34 rapidly increases the control current, and the rotation enters the uniform acceleration stage.

[0088] In this way, during the initial stage of system startup, the system flow rate is reduced (the proportional flow valve 2 operates at the minimum operating current) while ensuring that the system reaches the startup pressure. After the startup conditions are met, the current of the proportional flow valve 2 and the proportional relief valve 34 is further increased, so that the motor 4 enters the uniform acceleration stage.

[0089] Compared to the traditional pure flow regulation method, this gradual flow and pressure coordinated regulation method decouples the system pressure and flow during the slewing start-up process, effectively avoiding the pressure overshoot phenomenon caused by the instantaneous pressure build-up in the traditional start-up method. This significantly reduces the mechanical shock and vibration of the boom at the moment of start-up, improves the operating comfort and safety of the boom aerial work platform, and at the same time reduces the wear of hydraulic components and extends the service life of the system.

[0090] In some embodiments, during the initial braking phase of the slewing control system, the step of controlling the control current of the proportional flow valve 2 and the proportional relief valve 34 to make the pressures at port V1 and port B2 reach the locking condition of the second balance valve 32, and then reducing the pressure at port B2 after the second balance valve 32 is locked, includes:

[0091] In the initial first stage of braking of the slewing control system, the control current of the proportional flow valve 2 and the proportional relief valve 34 is reduced so that the pressure of oil port V1 and the pressure of oil port B2 reach the locking condition of the second balance valve 32.

[0092] In the initial second stage of braking of the slewing control system, the pressure at port B2 is reduced by continuing to decrease the control current of the proportional relief valve 34.

[0093] During the slewing braking phase:

[0094] like Figure 3 As shown, in the existing scheme, during rotary braking, after detecting that the output of the operating handle 7 is zero, the current of the proportional flow valve 2 drops to the minimum operating current and then drops to zero. At this time, the proportional flow valve 2 switches to the neutral position. V1 The descent is triggered, and the second balancing valve 32 locks out when the following conditions are met:

[0095]

[0096] At this time, due to the large moment of inertia of the boom, the boom drives the motor 4 to continue to rotate due to inertia. The motor 4 switches to pump mode, and the pressure at the oil port B2 of the motor 4 rises, causing the boom to vibrate.

[0097] Even with the addition of a slewing buffer valve, since its opening pressure is a fixed value, there will still be some boom vibration during the slewing start-stop phase.

[0098] Therefore, such as Figure 4 As shown, this application addresses the shortcomings of traditional designs during the slewing braking phase by adding a first shuttle valve 33, a proportional relief valve 34, a first check valve 38, and a second check valve 39 to the balance valve assembly 3. The two inlets of the first shuttle valve 33 are connected to oil ports C1 and C2, respectively, and its outlet is connected to the inlet of the proportional relief valve 34. The outlet of the proportional relief valve 34 is connected to the first check valve 38 and the second check valve 39. Depending on the operating conditions, the outlet of the proportional relief valve 34 can freely return oil to oil ports V1 and V2 via the first check valve 38 and the second check valve 39, respectively, thus solving the problem of traditional designs during the slewing braking phase. Specifically:

[0099] During the slewing braking phase:

[0100] like Figure 7 As shown, in the initial braking phase, after the operating handle 7 is detected to have returned to its original position, the current of the proportional flow valve 2 begins to decrease, and the opening of the proportional flow valve 2 decreases until the proportional flow valve 2 reaches its minimum operating current. At this point, the current of the proportional relief valve 34 decreases, causing the second balance valve 32 to lock. When the second balance valve 32 is locked, that is:

[0101]

[0102] Due to inertia, the turntable continues to rotate, driving the rotary motor 4 to switch to pump mode. The pressure at oil port B2 of motor 4 begins to increase, and the rotation speed gradually decreases.

[0103] Afterwards, the current of the proportional relief valve 34 decreases at a constant speed (its opening increases), which relieves the high pressure at port B2 caused by the boom's inertia.

[0104] In this way, during the initial braking phase of the slewing control system, the control current of the proportional flow valve 2 and the proportional relief valve 34 is coordinated to ensure that the pressures at port V1 and port B2 first reach the locking condition of the second balance valve 32. After the second balance valve 32 is reliably locked, the pressure at port B2 is reduced through the first shuttle valve 33 and the proportional relief valve 34. This braking control strategy effectively prevents boom vibration caused by pressure surges at port B2 of the motor 4 during braking, ensuring the smoothness and reliability of the braking process, avoiding impact damage to the boom structure caused by sudden pressure changes, and improving the stability and safety of the aerial work platform under braking conditions.

[0105] The aforementioned proportional relief valve 34 is a direct proportional relief valve, meaning that its control current is directly proportional to the system pressure. Of course, it can also be configured as an inverse proportional relief valve 34.

[0106] The boom-type aerial work platform provided in this application includes the slewing control system described in the above specific embodiments; other parts of the boom-type aerial work platform can be referred to in related technologies, and will not be elaborated here.

[0107] It should be noted that in this specification, relational terms such as first and second are used only to distinguish one entity from several other entities, and do not necessarily require or imply any such actual relationship or order between these entities.

[0108] The slewing control system, method, and boom-type aerial work platform provided in this application have been described in detail above. Specific examples have been used to illustrate the principles and implementation methods of this application. The descriptions of the embodiments above are only for the purpose of helping to understand the solution and core ideas of this application. It should be noted that those skilled in the art can make several improvements and modifications to this application without departing from the principles of this application, and these improvements and modifications also fall within the protection scope of this application.

Claims

1. A slewing control system, applied to a boom-type aerial work platform, characterized in that, Includes a main pump (1), a proportional flow valve (2), a balance valve assembly (3), and a motor (4); The balance valve group (3) includes a first balance valve (31), a second balance valve (32), a first shuttle valve (33) and a proportional relief valve (34), and the balance valve group (3) has oil port V1, oil port V2, oil port C1 and oil port C2; The oil outlet of the main pump (1) is connected to the oil inlet P of the proportional flow valve (2), the oil inlet A1 and oil inlet B1 of the proportional flow valve (2) are connected to the oil inlet V1 and the oil inlet V2 respectively, and the oil return port T of the proportional flow valve (2) is connected to the oil tank. The oil port C1 is connected to the oil port A2 of the motor (4), and the oil port C2 is connected to the oil port B2 of the motor (4). The oil port V1 is connected to the oil port C1 and the first inlet of the first shuttle valve (33) through the first balance valve (31); The oil port V2 is connected to the oil port C2 and the second inlet of the first shuttle valve (33) through the second balance valve (32); The outlet of the first shuttle valve (33) is connected to the inlet of the proportional relief valve (34), and the outlet of the proportional relief valve (34) is connected to the oil port V1 and the oil port V2.

2. The slewing control system as described in claim 1, characterized in that, It also includes a controller (6) and an operating handle (7). The controller (6) is signal-connected to the proportional flow valve (2) and the proportional relief valve (34). The operating handle (7) is signal-connected to the controller (6). The operating handle (7) is used to feed back control commands to the controller (6) so that the controller (6) controls the proportional flow valve (2) and the proportional relief valve (34) to work.

3. The slewing control system as described in claim 1, characterized in that, The balance valve assembly (3) further includes a first throttling element (35) and a second throttling element (36). The inlet of the first throttling element (35) is connected to the oil port V1, and the outlet of the first throttling element (35) is connected to the pilot port of the second balance valve (32). The inlet of the second throttling element (36) is connected to the oil port V2, and the outlet of the second throttling element (36) is connected to the pilot port of the first balance valve (31).

4. The slewing control system as described in claim 1, characterized in that, The balance valve group (3) also includes a second shuttle valve (37), and the balance valve group (3) also has an oil port C3. The first inlet and the second inlet of the second shuttle valve (37) are respectively connected to the oil port V1 and the oil port V2. The outlet of the second shuttle valve (37) is connected to the brake oil port C of the reducer (5) of the motor (4) through the oil port C3.

5. The slewing control system as described in claim 1, characterized in that, The proportional flow valve (2) is a three-position four-way proportional flow valve.

6. The slewing control system according to any one of claims 1-5, characterized in that, The balance valve group (3) further includes a first check valve (38) and a second check valve (39). The outlet of the proportional relief valve (34) is connected to the inlet of the first check valve (38) and the inlet of the second check valve (39). The outlet of the first check valve (38) and the outlet of the second check valve (39) are respectively connected to the oil port V1 and the oil port V2.

7. A slewing control method, applied to the slewing control system as described in any one of claims 1-6, characterized in that, include: In the initial stage of the start-up of the rotary control system, the control current of the proportional flow valve (2) and the proportional relief valve (34) is controlled so that the pressure of the oil port V1 and the pressure of the oil port B2 reach the rotary conditions of the motor (4), and the motor (4) enters the uniform acceleration stage after it starts to rotate. In the initial braking phase of the slewing control system, the control current of the proportional flow valve (2) and the proportional relief valve (34) is controlled so that the pressure of the oil port V1 and the pressure of the oil port B2 reach the locking condition of the second balance valve (32), and the pressure of the oil port B2 is reduced after the second balance valve (32) is locked.

8. The slewing control method as described in claim 7, characterized in that, In the initial startup phase of the rotary control system, the steps of controlling the control current of the proportional flow valve (2) and the proportional relief valve (34) to make the pressure of the oil port V1 and the pressure of the oil port B2 reach the rotary conditions of the motor (4), and entering the uniform acceleration phase after the motor (4) starts to rotate, include: In the initial first stage of the start-up of the rotary control system, the control current of the proportional flow valve (2) and the proportional relief valve (34) is increased so that the proportional flow valve (2) operates at a preset minimum operating current and the motor (4) starts to rotate. In the initial second stage of the start-up of the slewing control system, the motor (4) enters the uniform acceleration slewing stage by continuing to increase the control current of the proportional flow valve (2) and the proportional relief valve (34).

9. The slewing control method as described in claim 7, characterized in that, In the initial braking phase of the slewing control system, the steps of controlling the control current of the proportional flow valve (2) and the proportional relief valve (34) to make the pressure of port V1 and the pressure of port B2 reach the locking condition of the second balance valve (32), and reducing the pressure of port B2 after the second balance valve (32) is locked include: In the initial first stage of braking of the slewing control system, the control current of the proportional flow valve (2) and the proportional relief valve (34) is reduced so that the pressure of the oil port V1 and the pressure of the oil port B2 reach the locking condition of the second balance valve (32). In the initial second stage of braking of the slewing control system, the pressure of the oil port B2 is reduced by continuing to decrease the control current of the proportional relief valve (34).

10. A boom-type aerial work platform, characterized in that, Including the slewing control system as described in any one of claims 1-6.

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