Movable arm control system and electric vehicle

Abstract

The utility model discloses a movable arm control system and an electric vehicle, and the movable arm control system comprises a hydraulic cylinder which can drive a movable arm to act and comprises a rod cavity and a rodless cavity; the pressurizing valve group is communicated between the rod cavity and the oil tank; the power pump is communicated between the pressurizing valve group and the oil tank; the double-quadrant pump is communicated between the rodless cavity and the oil tank; the motor is in transmission connection with the double-quadrant pump; in a descending mode, the double-quadrant pump is in a motor working mode and rotates under gravitational potential energy of oil return of the rodless cavity so as to drive the motor to generate electricity and rotate; in the pressurizing mode, the pressurizing valve set is located at the first working position, and the power pump is in the working state so as to pump high-pressure hydraulic oil to the rod cavity. As above, oil ways between the rod cavity and the rodless cavity are controlled independently, valve control over the rod cavity and pump control over the rodless cavity are achieved, recycling of gravitational potential energy of oil return of the rodless cavity can be achieved through the double-quadrant pump and the motor, and the pressurizing working condition of the movable arm can be met through the pressurizing valve set and the power pump.

Description

Technical Field

[0001] The present application relates to the technical field of hydraulic systems, and more particularly to a boom control system, and also relates to an electric vehicle including the above boom control system. Background Art

[0002] For construction machinery such as excavators and material handlers, the construction machinery includes a boom and an attachment. The attachment is installed on the boom and the boom is driven to move by a boom hydraulic cylinder, and then the boom drives the attachment to move. The gravitational potential energy of the hydraulic oil in the boom hydraulic cylinder can be recovered and used for energy conservation. In some working conditions, such as when an excavator shovel presses a coal pile or a material handler presses a bale, the rod chamber of the boom hydraulic cylinder needs to drive the telescopic rod to retract to provide a pressing force.

[0003] However, in the existing construction machinery, the oil circuit between the rod chamber and the rodless chamber of the boom hydraulic cylinder needs to be switched through a multi-way valve. While achieving efficient recovery of the gravitational potential energy of the hydraulic oil in the rodless chamber without passing through the multi-way valve switching, it cannot meet the requirement of the boom driving the attachment to press the target object in some scenarios. Utility Model Content

[0004] In view of this, the present application provides a boom control system, and also provides an electric vehicle including the above boom control system, which solves the problem that the requirement of the boom driving the attachment to press the target object in some scenarios cannot be met while achieving the recovery of gravitational potential energy.

[0005] In order to achieve the above object, the present application provides the following technical solutions:

[0006] A boom control system includes:

[0007] A hydraulic cylinder capable of driving the boom to move to control the boom to enter a rising mode, a falling mode, and a pressurizing mode; the hydraulic cylinder includes a rod chamber and a rodless chamber;

[0008] A pressurizing valve group including a first working position, an intermediate working position, and a second working position, the pressurizing valve group being connected between the rod chamber and the fuel tank;

[0009] A power pump connected between the pressurizing valve group and the fuel tank;

[0010] A bi-quadrant pump including a pumping mode and a motor working mode; the bi-quadrant pump is connected between the rodless chamber and the fuel tank;

[0011] An electric motor drivingly connected to the bi-quadrant pump; wherein:

[0012] When the boom enters the lowering mode, the dual-quadrant pump is in the motor operating mode, the hydraulic oil in the rodless chamber is returned to the fuel tank, and the dual-quadrant pump rotates under the gravitational potential energy of the hydraulic oil to drive the motor to generate electricity and rotate;

[0013] When the boom enters the pressurizing mode, the pressurizing valve group is in the first working position to connect the oil circuit between the rod chamber and the fuel tank, and the power pump is in the working state to pump high-pressure hydraulic oil into the rod chamber.

[0014] Optionally, in the above boom control system, the pumping mode includes a pumping working mode and a pumping standby mode; where:

[0015] When the boom enters the raising mode, the dual-quadrant pump is in the pumping working mode to pump the hydraulic oil in the fuel tank into the rodless chamber through the dual-quadrant pump;

[0016] When the boom enters the pressurizing mode, the dual-quadrant pump is in the pumping standby mode, and the hydraulic oil entering the dual-quadrant pump from the fuel tank then flows back to the fuel tank.

[0017] Optionally, in the above boom control system, the boom control system includes a first pressure sensor;

[0018] The first pressure sensor is used to detect the oil return pressure P1 of the rodless chamber. When P1 < P 阈值1 , the boom switches from the lowering mode to the pressurizing mode, and at this time, the dual-quadrant pump switches from the motor operating mode to the pumping standby mode.

[0019] Optionally, in the above boom control system, the boom control system includes a position sensor;

[0020] The position sensor is used to detect the motion state of the boom when it is lowering. When the boom enters the stationary state, the boom switches from the lowering mode to the pressurizing mode, and at this time, the dual-quadrant pump switches from the motor operating mode to the pumping standby mode.

[0021] Optionally, in the above boom control system, the boom control system includes a make-up check valve, and the make-up check valve is connected between the rod chamber and the external system oil return circuit of the external hydraulic system;

[0022] Wherein, when the boom enters the lowering mode, the pressurizing valve group switches to the intermediate working position, and the pressurizing valve group blocks the oil circuit between the rod chamber and the fuel tank, so that the hydraulic oil in the external system oil return circuit is unidirectionally transported to the rod chamber through the make-up check valve.

[0023] Optionally, in the above boom control system, the boom control system includes a second pressure sensor; when the boom enters the lowering mode, the second pressure sensor is used to detect the oil inlet pressure P2 of the rod chamber;

[0024] When P2 < P 阈值2 the pressure boosting valve group is switched from the intermediate working position to the first working position, and the power pump operates to pump the hydraulic oil in the fuel tank to the rod chamber.

[0025] Optionally, in the above boom control system, the boom control system includes a plurality of rod chamber oil return circuits, each rod chamber oil return circuit is connected with a check valve, and at least one rod chamber oil return circuit is connected with a radiator; wherein:

[0026] When the boom enters the raising mode, the pressure boosting valve group is switched to the second working position, and the pressure boosting valve group connects the oil circuit between the rod chamber and the fuel tank to unidirectionally return the hydraulic oil in the rod chamber to the fuel tank through the check valve.

[0027] Optionally, in the above boom control system, the boom control system includes a unloading valve group, and the unloading valve group is connected in the circulating oil circuit between the double quadrant pump and the fuel tank;

[0028] When the boom enters the pressure boosting mode, the double quadrant pump is switched from the motor working mode to the pumping standby mode, and the unloading valve group is opened to realize the unloading of the double quadrant pump.

[0029] Optionally, in the above boom control system, a load holding valve is arranged between the rodless chamber and the double quadrant pump to keep the position of the boom fixed under the idle operation condition.

[0030] An electric vehicle includes the boom control system as described above.

[0031] In the boom control system and the electric vehicle provided by the present application, the oil circuits between the rod chamber and the rodless chamber are independently controlled respectively, realizing valve control of the rod chamber and pump control of the rodless chamber. It can not only realize the recovery and utilization of the gravitational potential energy of the oil return of the rodless chamber through the "double quadrant pump + motor", but also meet the pressure boosting working condition of the boom through the "pressure boosting valve group + power pump". While realizing the recovery of the gravitational potential energy of the hydraulic oil, it meets the requirement of the boom driving the attachment to press the target object in some scenarios. Description of the Drawings

[0032] To more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the accompanying drawings required for the description of the embodiments or the prior art. Obviously, the accompanying drawings in the following description are only the embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other accompanying drawings can also be obtained based on the provided drawings.

[0033] Figure 1 This is the hydraulic schematic diagram of the boom control system of the present application.

[0034] Figure 1 In the figure:

[0035] 1. Hydraulic cylinder; 2. Oil tank; 3. Pressure boosting valve group; 4. Power pump; 5. Bi-quadrant pump; 6. Motor; 7. First pressure sensor; 8. Make-up check valve; 9. Second pressure sensor; 10. Return check valve; 11. Radiator; 12. Unloading valve group; 13. Load holding valve;

[0036] 101. Rod chamber; 102. Rodless chamber; 103. Telescopic rod;

[0037] 301. Three-position three-way directional control valve; 302. First relief valve

[0038] 1201. First two-position two-way directional control valve; 1202. Second relief valve;

[0039] DT1. First energized position; DT0. Middle position; DT2. Second energized position. Detailed implementation manners

[0040] The present application provides a boom control system and also provides an electric vehicle including the above boom control system.

[0041] The following will clearly and completely describe the technical solutions in the embodiments of the present application with reference to the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments of the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present application.

[0042] As Figure 1As shown in the figure, an embodiment of the present application discloses a boom control system. The boom control system includes a hydraulic cylinder 1, a fuel tank 2, a pressure boosting valve group 3, a power pump 4, a two-quadrant pump 5, and a motor 6. The hydraulic cylinder 1 can drive the boom to move, so that the boom enters the ascending mode, the descending mode, and the pressure boosting mode. The hydraulic cylinder 1 includes a rod chamber 101 and a rodless chamber 102. The pressure boosting valve group 3 includes a first working position, an intermediate working position, and a second working position; the pressure boosting valve group 3 is connected between the rod chamber 101 and the fuel tank 2. The power pump 4 is connected between the pressure boosting valve group 3 and the fuel tank 2. The two-quadrant pump 5 includes a pumping working mode, a pumping standby mode, and a motor working mode; the two-quadrant pump 5 is connected between the rodless chamber 102 and the fuel tank 2. The motor 6 is drivingly connected to the two-quadrant pump 5.

[0043] When the boom enters the descending mode, the two-quadrant pump 5 switches to the motor working mode, the hydraulic oil in the rodless chamber 102 is returned to the fuel tank 2, and the two-quadrant pump 5 rotates under the gravitational potential energy of the hydraulic oil to drive the motor 6 to generate electricity and rotate. When the boom enters the pressure boosting mode, the attachment connected to the boom abuts against the target object; the pressure boosting valve group 3 is in the first working position to connect the oil circuit between the rod chamber 101 and the fuel tank 2; the power pump 4 is in the working state to pump high-pressure oil to the rod chamber 101 through the power pump; the two-quadrant pump 5 is in the pumping mode.

[0044] It should be noted that when the boom control system of the present application is used in construction machinery, the construction machinery includes a boom and an attachment connected to the boom, and the attachment is installed on the boom through the stick. The hydraulic cylinder 1 drives the boom to move, the movement of the boom drives the attachment to move, and the movement of the attachment further completes the operation on the target object. When the boom enters the ascending mode, the boom drives the attachment to rise relative to the target object; when the boom enters the descending mode, the boom drives the attachment to descend relative to the target object; when the boom enters the pressure boosting mode, the attachment abuts against the target object, and the boom drives the attachment to apply a pressing force to the target object. The construction machinery can be an excavator, the attachment is an excavator bucket, and the target object can be a coal pile; in the scenario where the excavator bucket presses the coal pile, the hydraulic cylinder 1 drives the boom to enter the pressure boosting mode, so that the boom drives the excavator bucket to apply a pressing force to the coal pile. The construction machinery can be a grapple system, the attachment is a grapple, and the target object can be a bale; in the scenario where the grapple presses the bale, the hydraulic cylinder 1 drives the boom to enter the pressure boosting mode, so that the boom drives the grapple to apply a pressing force to the bale.

[0045] It should be further noted that the hydraulic cylinder 1 includes a telescopic rod 103 which is arranged in the rod chamber 101; the telescopic rod 103 is connected to the boom, and the telescopic rod 103 acts to drive the boom to move synchronously. Specifically, when the oil enters the rodless chamber 102 and the oil returns from the rod chamber 101, the telescopic rod 103 rises, thereby driving the boom to rise; when the oil enters the rod chamber 101 and the oil returns from the rodless chamber 102, the telescopic rod 103 descends, thereby driving the boom to descend. The boom rises in the rising mode; the boom descends in the descending mode; the boom descends in the pressurizing mode.

[0046] Furthermore, the construction machinery includes a slewing platform, and the boom is hinged to the slewing platform. The hydraulic cylinder 1 drives the boom to rotate in the vertical direction; in the rising mode of the boom, the telescopic rod 103 rises (extends) to drive the boom to rotate upward, thereby realizing the rise of the boom in the height direction; in the descending mode and the pressurizing mode of the boom, the telescopic rod 103 descends (retracts) to drive the boom to rotate downward, thereby realizing the descent of the boom in the height direction.

[0047] Furthermore, in the descending mode of the boom, low-pressure hydraulic oil is delivered into the rod chamber 101; "low pressure" means that the boom descends by its own weight and does not require the rod chamber 101 to provide additional load for descent. At this time, the rod chamber 101 is at the pressure to prevent the hydraulic oil in the chamber from being sucked empty.

[0048] In the pressurizing mode of the boom, high-pressure hydraulic oil is delivered into the rod chamber 101; "high pressure" means that the rod chamber 101 generates additional load force. On the basis of the boom descending by its own weight, the boom also accelerates its descent relying on the load of the rod chamber 101. The rod chamber 101 can exert a sufficient large pressing force on the target object to make the arrangement of the target object more compact and cause compressive deformation.

[0049] By shaking the handle, an upward movement command, a downward movement command, and a pressurizing command are respectively input into the boom control system to correspondingly complete the upward movement working condition, the downward movement working condition, and the pressurizing working condition. In the upward movement working condition, the boom only enters the rising mode; in the downward movement working condition, the boom only enters the descending mode; in the pressurizing working condition, the boom first enters the descending mode and then enters the pressurizing mode.

[0050] In the pressurized working condition: ① First, enter the descending mode. At this time, low-pressure hydraulic oil is supplied to the rod chamber 101, and the telescopic rod 103 drives the boom to descend until the attachment contacts the target object, and the descending speed of the boom decreases sharply or becomes zero; ② When the descending speed of the boom decreases sharply or becomes zero, trigger to enter the pressurized mode. At this time, high-pressure hydraulic oil is pumped into the rod chamber 101 so that the telescopic rod 103 drives the attachment connected to the boom to generate a large downward pressing force on the target object. In the pressurized mode, due to the target object undergoing compressive deformation under the action of a large pressing force, the boom will generate a small downward displacement, a small amount of high-pressure hydraulic oil will be pumped into the rod chamber 101, and a small amount of hydraulic oil in the rodless chamber 102 will be returned to the fuel tank 2.

[0051] In the descending mode of the boom, when the rodless chamber 102 returns oil, the gravitational potential energy of the returned hydraulic oil is converted into the kinetic potential energy for driving the double-quadrant pump to rotate. The double-quadrant pump 5 rotates to drive the motor 6 to generate electricity and rotate. The motor 6 generates electricity and stores the electric energy in the battery module. The battery module is used to supply power to the electrical modules of the electric vehicle. As above, through the "double-quadrant pump 5 + motor 6", the efficient recovery and utilization of gravitational potential energy are realized.

[0052] Furthermore, in the pressurized mode of the boom, the pressurizing valve group 3 switches to the first working position to connect the oil circuit between the fuel tank 2 and the rod chamber 101 through the pressurizing valve group 3; at the same time, the power pump 4 is in the working state to pump high-pressure hydraulic oil from the fuel tank 2 to the rod chamber 101 through the power pump 4; as above, the "pressurizing valve group 3 + power pump 4" realizes that the boom drives the attachment to provide a large enough downward pressing force on the target object.

[0053] In summary, the oil circuits between the rod chamber 101 and the rodless chamber 102 are independently controlled respectively, realizing valve control of the rod chamber 101 and pump control of the rodless chamber 102. It can not only realize the recovery and utilization of the gravitational potential energy of the oil return in the rodless chamber 102 through the "double-quadrant pump 5 + motor 6", but also meet the requirement of applying high pressure to the rod chamber 101 through the "pressurizing valve group 3 + power pump 4" to complete the pressurized working condition of the boom.

[0054] In some embodiments, one, or two, or three, or more hydraulic cylinders 1 are provided, and all the hydraulic cylinders 1 act synchronously to drive the boom to act.

[0055] In some embodiments of the present application, the pumping mode includes a pumping working mode and a pumping standby mode. When the boom enters the rising mode, the dual-quadrant pump 5 switches to the pumping working mode to pump the hydraulic oil in the fuel tank 2 to the rodless cavity 102 through the dual-quadrant pump 5. When the boom enters the falling mode, the dual-quadrant pump 5 is in the motor working mode, and the dual-quadrant pump 5 drives the motor 6 to generate electricity and rotate. When the boom enters the pressurizing mode, the dual-quadrant pump 5 is in the pumping standby mode, and the hydraulic oil entering the dual-quadrant pump 5 through the fuel tank 2 then flows back to the fuel tank 2.

[0056] When the boom enters the rising mode, the dual-quadrant pump 5 is in the pumping working mode, and it functions as a liquid pump to pump the hydraulic oil in the fuel tank 2 to the rodless cavity 102. In the falling mode of the boom, the dual-quadrant pump 5 is in the motor working mode, and it functions as a motor. The hydraulic oil in the rodless cavity 102 is returned to the fuel tank 2, and the dual-quadrant pump 5 rotates under the gravitational potential energy of the hydraulic oil to drive the motor 6 to generate electricity and rotate for reverse charging and energy storage. As above, through the combined structure of "dual-quadrant pump 5 + motor 6", the recovery and utilization of the gravitational potential energy of the hydraulic oil in the rodless cavity 102 of the hydraulic cylinder 1 during the descending action of the boom are realized; moreover, through the switching of the working mode of the dual-quadrant pump 5, the pump control of the oil inlet and return functions of the rodless cavity 102 is achieved, and the effect of adjustable lifting and lowering speeds of the boom is achieved.

[0057] Furthermore, when the boom enters the pressurizing mode, the dual-quadrant pump 5 is in the pumping standby mode, and the power consumption of the dual-quadrant pump 5 is the lowest when it is in a non-stop state.

[0058] When the boom enters the falling mode and the rodless cavity 102 returns oil, the gravitational potential energy of the returning hydraulic oil → high-pressure hydraulic oil (high-pressure hydraulic oil is obtained under the action of gravitational potential energy) → the dual-quadrant pump 5 rotates (the high-pressure hydraulic oil drives the dual-quadrant pump to rotate) → the motor 6 rotates (the dual-quadrant pump 5 drives the motor to generate electricity and rotate) → the battery stores; as above, the efficient recovery and utilization of gravitational potential energy are realized. The recoverable range of the returning gravitational potential energy is large during the energy conversion process, there is no overflow loss, and the control is simple, safe and reliable.

[0059] Assume the action process. The displacement of the hydraulic cylinder 1 is L, the pump port pressure of the dual-quadrant pump 5 is P, and the cross-sectional area of the rodless cavity of the hydraulic cylinder 1 is A. Then the energy in the lifting and lowering mode The ratio of the recovered potential energy in the falling mode to the energy consumption in the rising mode is the recovery efficiency. The recovery efficiency Among them, n1 is the transmission coefficient from the motor 6 to the bi-quadrant pump 5 in the pumping working mode, and n2 is the transmission coefficient from the bi-quadrant pump 5 in the motor working mode to the motor 6. The recovery efficiency is related to the pressure P in the descending mode. The traditional accumulator + energy-saving oil cylinder mode is affected by the cylinder displacement L and the cylinder pressure, and the overall recovery efficiency is not high. However, in this application, through the mode of the motor 6 + bi-quadrant pump 5, the recoverable interval is large during the conversion process, there is no overflow loss, and the control is simple, safe and reliable.

[0060] In some embodiments of this application, the boom control system includes a first pressure sensor 7. When a pressurization instruction is input, the first pressure sensor 7 is used to detect the oil return pressure P1 of the rodless cavity 102. When P1 < P 阈值1 the boom switches from the descending mode to the pressurization mode, and at this time, the bi-quadrant pump 5 switches from the motor working mode to the pumping standby mode.

[0061] It should be noted that when P1 < P 阈值1 it means that the oil return volume of the rodless cavity 102 becomes very small or reduces to zero. At this time, the attachment abuts against the target object and the descending speed of the boom decreases extremely or reduces to zero. The first pressure sensor 7 detects the oil return pressure P1 of the rodless cavity 102 in real time, that is, the pressure at the oil inlet of the bi-quadrant pump 5 when the bi-quadrant pump 5 is in the motor working mode.

[0062] The pressurization condition includes two stages: ① The boom first enters the descending mode. At this time, the bi-quadrant pump 5 is in the motor working mode, and the first pressure sensor 7 detects the oil return pressure P1 of the rodless cavity 102 in real time; ② When the pressure value P1 detected by the first pressure sensor 7 < P 阈值1 the first pressure sensor 7 transmits the detected pressure signal to the controller, and the controller processes the received pressure signal and controls the boom to automatically switch from the descending mode to the pressurization mode. At this time, the bi-quadrant pump 5 switches from the motor working mode to the pumping standby mode, the pressurization valve group 3 is in the first working position, and the power pump 4 is in the working state to pump high-pressure hydraulic oil into the rod cavity 101.

[0063] In the pressurization condition, the boom first enters the descending mode and then switches to the pressurization mode. During the above process, the boom performs a descending action. By setting the first pressure sensor 7, the oil return pressure P1 of the rodless cavity 102 can be detected in real time when the boom performs a descending action. When P1 < P 阈值1 the boom can be automatically switched from the descending mode to the pressurization mode without the need to input a control instruction manually. Its action response is accurate and the operation is reliable.

[0064] Further, the first pressure sensor 7 is communicated with the "oil circuit between the hydraulic cylinder 1 and the bi-quadrant pump 5" to detect the oil return pressure of the rodless cavity 102, so as to judge whether the boom descends to make the attachment contact the target object. The first pressure sensor 7 can be any one of a piezoresistive pressure sensor, a strain gauge pressure sensor, a capacitive pressure sensor, etc.

[0065] In some embodiments of the present application, the boom control system includes a position sensor, and the position sensor is used to detect the motion state when the boom descends. When the boom enters the stationary rotation state, the boom switches from the lowering mode to the pressurization mode, and at this time, the bi-quadrant pump 5 switches from the motor working mode to the pumping standby mode.

[0066] It should be noted that when the boom enters the stationary state, it means that the oil return amount of the rodless cavity 102 is zero. At this time, the attachment contacts the target object, and the lowering speed of the boom is reduced to zero. The pressurization working condition includes two stages: ① The boom first enters the lowering mode. At this time, the bi-quadrant pump 5 is in the motor working mode, and the position sensor is used to detect the motion state of the boom in real time; ② When the position sensor detects that the boom is in the stationary state, the position sensor transmits the detected position signal to the controller, and the controller processes the received position signal and controls the boom to automatically switch from the lowering mode to the pressurization mode. At this time, the bi-quadrant pump 5 switches from the motor working mode to the pumping standby mode, the pressurizing valve group 3 is in the first working position, and the power pump 4 is in the working state to pump high-pressure oil to the rod cavity 101.

[0067] As above, by setting the position sensor, the motion state of the boom during the lowering action can be detected in real time. And when the boom runs to the stationary state, the boom is automatically switched from the lowering mode to the pressurization mode without the need to input control instructions manually, with accurate action response and reliable operation.

[0068] Further, the position sensor can be an angle sensor. The angle sensor is installed on the boom to detect the rotation angle of the boom when the hydraulic cylinder 1 drives the boom to move, so as to judge whether the boom descends to make the attachment contact the target object. The angle sensor can be any one of an encoder, an inclination sensor, etc.

[0069] In some embodiments, in the boom control system, the first pressure sensor 7 and the position sensor can be set alternatively, or both can be set.

[0070] In some embodiments of the present application, the boom control system includes a make-up check valve 8, and the make-up check valve 8 is connected between the rod chamber 101 and the return oil circuit of the external hydraulic system. When the boom enters the lowering mode, the pressure regulating valve group 3 switches to the intermediate working position, and the pressure regulating valve group 3 blocks the oil circuit between the rod chamber 101 and the fuel tank 2, so that the hydraulic oil in the return oil circuit of the external system is unidirectionally conveyed to the rod chamber 101 through the make-up check valve 8.

[0071] It should be noted that the make-up check valve 8 can only achieve the unidirectional conveyance of hydraulic oil from the return oil circuit of the external system to the rod chamber 101. The external hydraulic system refers to other hydraulic systems except the boom control system, such as the stick hydraulic control system.

[0072] In the lowering mode of the boom, the pressure regulating valve group 3 switches to the intermediate working position, and the pressure regulating valve group 3 blocks the oil circuit between the fuel tank 2 and the rod chamber 101. At this time, the hydraulic oil in the return oil circuit of the external hydraulic system is unidirectionally conveyed to the rod chamber 101 through the make-up check valve 8. Since there is a certain return oil pressure in the return oil circuit of the external system, it is not necessary to rely on other pumping systems to supply oil to the rod chamber 101, which saves energy and meets the normal lowering requirements of the boom.

[0073] In some embodiments of the present application, the boom control system includes a second pressure sensor 9. When the boom enters the lowering mode, the second pressure sensor 9 is used to detect the inlet oil pressure P2 of the rod chamber 101. When P2 < P 阈值2 , the pressure regulating valve group 3 switches from the intermediate working position to the first working position, and the power pump 4 starts to work to pump the hydraulic oil in the fuel tank 2 to the rod chamber 101.

[0074] It should be noted that the lowering mode of the boom includes two states: ① normal lowering state; ② accelerated lowering state.

[0075] When the boom is in the accelerated lowering state, supplying oil to the rod chamber 101 only through the return oil circuit of the external system cannot meet the oil inlet volume of the rod chamber 101, which may lead to the phenomenon of cavitation in the rod chamber 101. When P2 < P 阈值2 , it indicates that the oil supply volume for supplying oil to the rod chamber 101 during the lowering of the boom is insufficient, and the boom is in the accelerated lowering state.

[0076] By setting the second pressure sensor 9, the inlet oil pressure P2 of the rod chamber 101 in the lowering mode of the boom can be detected in real time, and thus it can be detected in real time whether the boom is in the accelerated lowering state; when P2 detected by the second pressure sensor 9 < P 阈值2When this occurs, it indicates that the boom is in the state of accelerating downward. At this time, the second pressure sensor 9 transmits the detected pressure signal to the controller. The controller processes the received pressure signal and controls the pressurizing valve group 3 to switch from the intermediate working position to the first working position, and the power pump 4 starts to work. The pressurizing valve group 3 connects the oil circuit between the oil tank 2 and the rod chamber 101, and the power pump 4 pumps the hydraulic oil in the oil tank 2 to the rod chamber 101. As described above, the oil supply volume to the rod chamber 101 is increased, effectively avoiding the phenomenon of air suction in the rod chamber 101.

[0077] Further, the second pressure sensor 9 is connected to the "oil circuit where the hydraulic cylinder 1 is connected to the return oil circuit of the external system" to detect the oil inlet pressure of the rod chamber 101, so as to judge whether the boom enters the state of accelerating downward. The second pressure sensor 9 can be any one of a piezoresistive pressure sensor, a strain gauge pressure sensor, a capacitive pressure sensor, etc.

[0078] In some embodiments of the present application, the boom control system includes several rod chamber return oil circuits, and each rod chamber return oil circuit is connected with a check valve 10 for return oil. At least one rod chamber return oil circuit is connected with a radiator 11. When the boom enters the rising mode, the pressurizing valve group 3 switches to the second working position, and the pressurizing valve group 3 connects the oil circuit between the rod chamber 101 and the oil tank 2 to unidirectionally return the hydraulic oil in the rod chamber 101 to the oil tank 2 through the check valve 10 for return oil.

[0079] By setting the check valve 10 for return oil, the unidirectional return of the hydraulic oil from the rod chamber 101 to the oil tank 2 is realized, ensuring the stable and reliable operation of the hydraulic cylinder 1 driving the boom to rise. Further, by connecting the radiator 11 to the rod chamber return oil circuit, the effect of cooling the returned hydraulic oil is realized. This not only avoids the aging of the hydraulic oil caused by high temperature, extends the service life of the hydraulic oil, but also avoids the damage of hydraulic components and system failures caused by high temperature, reducing the maintenance cost and downtime.

[0080] Preferably, there are two rod chamber return oil circuits, and the opening pressure values of the check valves 10 for return oil on the two rod chamber return oil circuits are X and Y respectively, where: X < Y, 1 bar ≤ X ≤ 4 bar, 3.5 bar ≤ Y ≤ 6 bar. More preferably, X = 2.5 bar and Y = 4.5 bar.

[0081] Further, the opening pressure values of different check valves 10 for return oil are different, and at least the radiator 11 is connected to the rod chamber return oil circuit where the check valve 10 with the smallest opening pressure value is located.

[0082] As described above, regardless of whether the oil return amount of the rod chamber 101 is large or small, the oil can always be returned through the oil return circuit of the rod chamber where the oil return check valve 10 with the smallest opening pressure value is located. Therefore, at least part of the hydraulic oil can always be cooled. Moreover, according to the size of the oil return amount, different numbers of oil return check valves 10 can be opened, thereby connecting different numbers of oil return circuits of the rod chambers. Its flexible applicability is strong, ensuring the smooth reliability of the oil return effect of the rod chamber 101.

[0083] In some embodiments, the pressurizing valve group 3 includes a three-position three-way directional control valve 301. The three-position three-way directional control valve 301 includes the energized position of DT1, the non-energized position, and the energized position of DT2; the pressurizing valve group 3 includes an oil inlet P, an oil return port T1, and an oil outlet A. The oil inlet P and the oil return port T1 are respectively connected to the fuel tank 2, and the oil outlet A is connected to the rod chamber 101. When the three-position three-way directional control valve 301 is in the energized position of DT1, the pressurizing valve group 3 is in the first working position. At this time, the oil inlet P is connected to the oil outlet A to supply oil to the rod chamber 101; when the three-position three-way directional control valve 301 is in the non-energized position, the pressurizing valve group 3 is in the intermediate working position. At this time, neither the oil inlet P nor the oil return port T1 is connected to the oil outlet A, and oil is supplied to the rod chamber 101 through the external system oil return circuit; when the three-position three-way directional control valve 301 is in the energized position of DT2, the pressurizing valve group 3 is in the second working position. At this time, the oil outlet A is connected to the oil return port T1 to return the hydraulic oil in the rod chamber 101 to the fuel tank 2.

[0084] Furthermore, the pressurizing valve group 3 further includes a first relief valve 302, and the first relief valve 302 is connected in parallel with the three-position three-way directional control valve 301; the pressurizing valve group 3 includes an oil return port T2, and the first relief valve 302 is connected between the oil outlet A and the oil return port T2. When the three-position three-way directional control valve 301 is in the energized position of DT2 and the oil return pressure of the oil outlet A is relatively large, the first relief valve 302 is in the conducting state to increase the oil return amount of the pressurizing valve group 3. When the oil return pressure of the oil outlet A ≥ 25 MPa, the first relief valve 302 switches to the conducting state.

[0085] In some embodiments of the present application, the boom control system includes a unloading valve group 12, and the unloading valve group 12 is connected in the circulation oil circuit between the bi-quadrant pump 5 and the fuel tank 2. When the hydraulic cylinder 1 drives the boom into the pressurizing mode, the bi-quadrant pump 5 switches from the motor operating mode to the pumping standby mode, and the unloading valve group 12 connects the oil circuit between the rod chamber 101 and the fuel tank 2 to realize the unloading of the bi-quadrant pump 5.

[0086] It should be noted that the "pumping standby mode of the bi-quadrant pump 5" means that the bi-quadrant pump 5 functions as a liquid pump, and the displacement signal of the liquid pump is given to the minimum.

[0087] When the boom enters the pressurization mode, the oil return volume of the rodless chamber 102 is very small, and the bi-quadrant pump 5 no longer needs to function as a motor. At this time, the bi-quadrant pump 5 is switched from the motor operating mode to the pumping standby mode, so that while not shutting down the bi-quadrant pump 5, the energy loss of the bi-quadrant pump 5 is minimized. Further, when the bi-quadrant pump 5 is in the pumping standby mode, the unloading valve group 12 connects the circulating oil circuit between the bi-quadrant pump 5 and the fuel tank 2, thereby reliably avoiding the cavitation phenomenon of the bi-quadrant pump 5 and ensuring the service life of the bi-quadrant pump 5.

[0088] In some embodiments, the unloading valve group 12 includes a first two-position two-way directional control valve 1201, and the first two-position two-way directional control valve 1201 includes a first unidirectional conduction working position and a first bidirectional conduction working position. When the first two-position two-way directional control valve 1201 is energized, it is in the first unidirectional conduction working position to cut off the circulating oil circuit between the bi-quadrant pump 5 and the fuel tank 2; when the first two-position two-way directional control valve 1201 is not energized, it is in the first bidirectional conduction working position to connect the circulating oil circuit between the bi-quadrant pump 5 and the fuel tank.

[0089] In the pressurization mode of the boom, the first two-position two-way directional control valve 1201 is in the first bidirectional conduction working position to unload the bi-quadrant pump 5 when the bi-quadrant pump 5 is in the pumping standby mode. In the lowering mode of the boom, the first two-position two-way directional control valve 1201 is in the first unidirectional conduction working position, so that when the bi-quadrant pump 5 is in the motor operating mode, the hydraulic oil flowing back from the rodless chamber 102 is not directly returned to the fuel tank 2 through the unloading valve group 12, but is returned to the fuel tank 2 after the work of the bi-quadrant pump 5. In the raising mode of the boom, the first two-position two-way directional control valve 1201 is in the first unidirectional conduction working position, so that when the bi-quadrant pump 5 is in the pumping working mode, the hydraulic oil pumped by the bi-quadrant pump 5 is not directly returned to the fuel tank 2 through the unloading valve group 12, but all flows to the rodless chamber 102.

[0090] Further, the unloading valve group 12 further includes a second relief valve 1202 connected in parallel with the first two-position two-way directional control valve 1201. When the first two-position two-way directional control valve 1201 is in the first bidirectional conduction working position and the oil pressure of the hydraulic oil pumped out by the bi-quadrant pump 5 is relatively high, the second relief valve 1202 is in the conducting state to increase the oil return volume of the unloading valve group 12.

[0091] In some embodiments of the present application, a load holding valve 13 is provided between the rodless chamber 102 and the bi-quadrant pump 5 to keep the position of the boom fixed during the idle operation condition.

[0092] It should be noted that the "idle operation condition" refers to a low - energy - consumption and low - activity state that the boom control system enters when it does not need to perform main tasks such as the rising condition, the falling condition, and the pressurizing condition; on the premise of not affecting the boom control system's ability to resume work at any time, energy consumption and unnecessary wear are reduced as much as possible.

[0093] By setting the load - holding valve 13, in the idle condition, the boom is prevented from descending due to its own gravity, enabling the boom to safely and reliably maintain its position unchanged.

[0094] Furthermore, the load - holding valve 13 is a two - position two - way solenoid valve, which includes a second one - way conduction working position and a second two - way conduction working position. When the load - holding valve 13 is energized, it is in the second two - way conduction working position; when the load - holding valve 13 is de - energized, it is in the second one - way conduction working position.

[0095] In the idle operation condition, the load - holding valve 13 is in the second one - way conduction working position to prevent the hydraulic oil in the rodless cavity 102 from being returned to the oil tank 2, thereby preventing the boom from descending and keeping the position of the boom fixed. In the rising condition, the load - holding valve 13 is in the second one - way conduction working position to achieve the one - way delivery of hydraulic oil from the oil tank 2 to the rodless cavity 102. In the falling condition and the pressurizing condition, the load - holding valve 13 is in a two - way conduction state to achieve the return of hydraulic oil from the rodless cavity 102 to the oil tank 2.

[0096] Table 1 is a summary table of the working positions of the pressurizing valve group 3 connected to the rod - end chamber 101 and the working states of the power pump 4 in each working mode.

[0097] Table 1

[0098]

[0099] Table 2 is a summary table of the modes of the bi - quadrant pump 5 connected to the rodless cavity 102, the working states of the motor 6, the working positions of the unloading valve group 12, and the working positions of the load - holding valve 13 in each working mode.

[0100] Table 2

[0101]

[0102]

[0103] Table 3 is a summary table of the modes of the bi - quadrant pump 5, the energized states of the pressurizing valve group 3, the energized states of the unloading valve group 12, and the energized states of the load - holding valve 13 in each working mode.

[0104] Table 3

[0105]

[0106] In summary, the present application also provides an electric vehicle, which includes the boom control system as described above.

[0107] Since the electric vehicle of the present application includes the boom control system as described above, for the beneficial effects brought by the boom control system to the electric vehicle, please refer to the above, and will not be elaborated here.

[0108] The components and devices involved in the present application are only illustrative examples and do not intend to require or imply that they must be connected, arranged, and configured in the manner shown in the drawings. As those skilled in the art will recognize, these components and devices can be connected, arranged, and configured in any way. Words such as "comprising", "including", "having", etc. are open-ended terms, meaning "including but not limited to", and can be used interchangeably with each other. The word "or" and "and" used herein refer to the word "and / or", and can be used interchangeably with it, unless the context clearly indicates otherwise. The word "such as" used herein refers to the phrase "such as but not limited to", and can be used interchangeably with it.

[0109] It should also be noted that in the device of the present application, each component can be disassembled and / or recombined. These disassembly and / or recombination should be regarded as equivalent solutions of the present application.

[0110] The above description of the disclosed aspects is provided to enable any person skilled in the art to make or use the present application. Various modifications to these aspects are very obvious to those skilled in the art, and the general principles defined herein can be applied to other aspects without departing from the scope of the present application. Therefore, the present application is not intended to be limited to the aspects shown herein, but to the broadest scope consistent with the principles and novel features disclosed herein.

[0111] The above description has been given for purposes of illustration and description. In addition, this description is not intended to limit the embodiments of the present application to the forms disclosed herein. Although multiple example aspects and embodiments have been discussed above, those skilled in the art will recognize certain variations, modifications, changes, additions, and sub-combinations thereof.

[0112] The above are only the preferred embodiments of the present application and are not intended to limit the present application. Any modifications, equivalent replacements, etc. made within the spirit and principles of the present application shall be included within the protection scope of the present application.

Claims

1. An arm control system, characterized in that, Comprising: A hydraulic cylinder (1) capable of driving the boom to move to control the boom to enter the ascending mode, descending mode, and pressurizing mode; the hydraulic cylinder (1) includes a rod chamber (101) and a rodless chamber (102); A pressurizing valve group (3) including a first working position, an intermediate working position, and a second working position, the pressurizing valve group (3) being connected between the rod chamber (101) and the fuel tank (2); A power pump (4) connected between the pressurizing valve group (3) and the fuel tank (2); A bi-quadrant pump (5) including a pumping mode and a motor working mode; the bi-quadrant pump (5) is connected between the rodless chamber (102) and the fuel tank (2); An electric motor (6) drivingly connected to the bi-quadrant pump (5); wherein: When the boom enters the descending mode, the bi-quadrant pump (5) is in the motor working mode, the hydraulic oil in the rodless chamber (102) is returned to the fuel tank (2), and the bi-quadrant pump (5) rotates under the gravitational potential energy of the hydraulic oil to drive the electric motor (6) to generate electricity and rotate; When the boom enters the pressurizing mode, the pressurizing valve group (3) is in the first working position to connect the oil circuit between the rod chamber (101) and the fuel tank (2), and the power pump (4) is in a working state to pump high-pressure hydraulic oil into the rod chamber (101).

2. The boom control system according to claim 1, wherein The pumping mode includes a pumping working mode and a pumping standby mode; wherein: When the boom enters the ascending mode, the bi-quadrant pump (5) is in the pumping working mode to pump the hydraulic oil in the fuel tank (2) into the rodless chamber (102) through the bi-quadrant pump (5); When the boom enters the pressurizing mode, the bi-quadrant pump (5) is in the pumping standby mode, and the hydraulic oil entering the bi-quadrant pump (5) from the fuel tank (2) then flows back to the fuel tank (2).

3. The boom control system according to claim 2, characterized in that, The boom control system includes a first pressure sensor (7); The first pressure sensor (7) is used to detect the oil return pressure P1 of the rodless cavity (102). When P1 < P 阈值1 at this time, the boom is switched from the lowering mode to the pressurizing mode, and at this time, the double quadrant pump (5) is switched from the motor operating mode to the pumping standby mode.

4. The boom control system according to claim 2, wherein, The boom control system includes a position sensor; The position sensor is used to detect the movement state of the boom when it descends. When the boom enters a stationary state, the boom switches from the descending mode to the pressurizing mode. At this time, the bi-quadrant pump (5) switches from the motor working mode to the pumping standby mode.

5. The boom control system according to claim 1, wherein, The boom control system includes a make-up check valve (8), and the make-up check valve (8) is connected between the rod chamber (101) and the external system return oil circuit of the external hydraulic system; Wherein, when the boom enters the descending mode, the pressurizing valve group (3) switches to the intermediate working position, and the pressurizing valve group (3) blocks the oil circuit between the rod chamber (101) and the fuel tank (2), so that the hydraulic oil in the external system return oil circuit is unidirectionally conveyed to the rod chamber (101) through the make-up check valve (8).

6. The boom control system according to claim 5, characterized in that, The boom control system includes a second pressure sensor (9); when the boom enters the descending mode, the second pressure sensor (9) is used to detect the inlet oil pressure P2 of the rod chamber (101). When P2 < P 阈值2 the pressure regulating valve group (3) switches from the intermediate working position to the first working position, and the power pump (4) operates to pump the hydraulic oil in the oil tank (2) into the rod chamber (101).

7. The boom control system according to claim 1, wherein The boom control system includes a plurality of rod-end oil return circuits, and each rod-end oil return circuit is connected to an oil return check valve (10). At least one of the rod-end oil return circuits is connected to a radiator (11); wherein: When the boom enters the lifting mode, the pressurizing valve group (3) switches to the second working position, and the pressurizing valve group (3) connects the oil circuit between the rod-end chamber (101) and the fuel tank (2) to return the hydraulic oil in the rod-end chamber (101) to the fuel tank (2) unidirectionally through the oil return check valve (10).

8. The boom control system according to claim 2, wherein The boom control system includes a unloading valve group (12), and the unloading valve group (12) is connected in the circulation oil circuit between the bi-quadrant pump (5) and the fuel tank (2); When the boom enters the pressurizing mode, the bi-quadrant pump (5) switches from the motor working mode to the pumping standby mode, and the unloading valve group (12) is opened to unload the bi-quadrant pump (5).

9. The boom control system according to claim 2, wherein, A load holding valve (13) is arranged between the rodless chamber (102) and the bi-quadrant pump (5) to keep the position of the boom fixed under the idle operation condition.

10. An electric vehicle, characterized in that, It includes the boom control system according to any one of claims 1-9.

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