Hydraulic drive system and material crushing vehicle

Abstract

The present invention relates to the field of hydraulic technology, and discloses a hydraulic drive system and a material crushing vehicle. The system includes: a variable pump assembly; a hydraulic motor for driving the cutting tool disc of the crushing device. The oil inlet of the hydraulic motor is connected to the oil outlet of the variable pump assembly through a first oil circuit, and the oil outlet of the hydraulic motor is connected to the oil inlet of the variable pump assembly through a second oil circuit; a pressure regulating device is connected to the second oil circuit and is used to dynamically control the pressure of the second oil circuit when the hydraulic motor is in a braking state. When the pressure of the hydraulic oil in the second oil circuit exceeds the set pressure, the hydraulic oil in the second oil circuit is shunted to avoid excessive braking torque, reduce the risk of cutter head shaft fracture, and reduce the pressure shock of the variable pump assembly and the hydraulic motor.

Description

Technical Field

[0001] The present invention relates to the technical field of hydraulics, and in particular, to a hydraulic drive system and a material shredding vehicle. Background Art

[0002] The material shredding vehicle has the functions of shredding, collecting, transporting, and discharging garden waste such as branches and tree trunks, and is suitable for the shredding and volume reduction, collection, and transportation operations of garden waste such as branches and tree trunks trimmed from roadside trees on urban roads, highway roadside trees, and park scenic trees. The shredding device is an important working component on the material shredding vehicle, and it is generally provided with a feed hopper, a feed roller, a cutting tool disc (tool roller), a discharge pipe, a hydraulic drive motor, etc. Its cutting tool disc is generally driven by a hydraulic system, and the hydraulic system includes a hydraulic pump, a hydraulic motor, etc.

[0003] There are certain risks when the shredding device of the existing material shredding vehicle is working. Since the cutting tool disc of the shredding device is a large-inertia device, accelerating from zero speed to the working speed requires a large amount of power and a certain amount of time; similarly, when reducing from the working speed to zero speed, if inertial rotation self-stop is adopted, it may take several minutes or more than ten minutes to completely stop; in some cases, it will cause potential safety hazards during shutdown; there is a high-frequency impact load during the cutting process of the tool disc. For example, when shredding branches, due to the large difference in the diameters of branches, when branches of different sizes are continuously fed, it will cause a sharp change in the cutting load; at the same time, the cutting frequency of the cutting blade is also relatively high, and the combined effect of the two will cause high-frequency pressure shocks in the hydraulic system. Summary of the Invention

[0004] Aiming at the above deficiencies in the prior art, the purpose of the embodiments of the present invention is to provide a hydraulic drive system and a material shredding vehicle to solve at least one technical problem in the prior art.

[0005] To achieve the above purpose, the first aspect of the present invention provides a hydraulic drive system, including:

[0006] A variable pump assembly;

[0007] A hydraulic motor for driving the cutting tool disc of the shredding device to work. The oil inlet of the hydraulic motor is connected to the oil outlet of the variable pump assembly through a first oil circuit, and the oil outlet of the hydraulic motor is connected to the oil inlet of the variable pump assembly through a second oil circuit;

[0008] A pressure regulating device is connected to the second oil circuit and is used to divert the hydraulic oil in the second oil circuit to reduce the pressure of the hydraulic oil when the pressure of the hydraulic oil in the second oil circuit exceeds the maximum set pressure when the hydraulic motor is in a braking state.

[0009] In the embodiments of the present invention, the pressure regulating device includes:

[0010] A first overflow valve;

[0011] Check valve

[0012] Wherein, the first relief valve and the check valve are connected in series between the first oil circuit and the second oil circuit, and the check valve only allows hydraulic oil to flow from the second oil circuit to the first oil circuit.

[0013] In an embodiment of the present invention, it further includes: a controller configured to:

[0014] Determine the braking mode of the hydraulic motor;

[0015] When the braking mode is the emergency stop mode, set the maximum allowable pressure of the first relief valve to the first pressure value;

[0016] When the braking mode is a non-emergency stop mode, set the maximum allowable pressure of the first relief valve to the second pressure value;

[0017] Wherein, the second pressure value is less than the first pressure value.

[0018] In an embodiment of the present invention, the pressure regulating device further includes:

[0019] A throttle valve connected in series between the first relief valve and the second oil circuit.

[0020] In an embodiment of the present invention, the pressure regulating device further includes:

[0021] A first accumulator connected to the second oil circuit.

[0022] In an embodiment of the present invention, the pressure regulating device includes:

[0023] A second accumulator; and

[0024] A first solenoid valve;

[0025] The second accumulator is connected to the second oil circuit through the first solenoid valve;

[0026] The hydraulic drive system further includes a controller configured to control the first solenoid valve to open when the hydraulic motor is in a braking state, so that the second accumulator is communicated with the second oil circuit.

[0027] In an embodiment of the present invention, the pressure regulating device further includes:

[0028] A second relief valve, the first end of the second relief valve is connected to the second accumulator, and is used to set the maximum working pressure of the second accumulator;

[0029] The controller is further configured to:

[0030] Determine the braking mode of the hydraulic motor;

[0031] When the braking mode is the emergency stop mode, set the maximum allowable pressure of the second overflow valve to the first pressure value to set the maximum working pressure of the second accumulator to the first maximum working pressure;

[0032] When the braking mode is not the emergency stop mode, set the maximum allowable pressure of the second overflow valve to the second pressure value to set the maximum working pressure of the second accumulator to the second maximum working pressure;

[0033] Wherein, the second pressure value is less than the first pressure value.

[0034] In the embodiment of the present invention, the variable pump assembly includes a make-up oil pump; the hydraulic drive system further includes a cooler, and the second end of the second overflow valve is connected to the make-up oil circuit of the make-up oil pump through the cooler.

[0035] In the embodiment of the present invention, the pressure regulating device further includes:

[0036] A third accumulator, connected to the first oil circuit.

[0037] In the embodiment of the present invention, the variable pump assembly includes:

[0038] A pressure detection device, configured to control the variable pump assembly to stop increasing the displacement when it detects that the oil pressure at the oil outlet of the variable pump assembly exceeds the maximum working pressure of the system.

[0039] In the embodiment of the present invention, the variable pump assembly further includes:

[0040] A variable control valve;

[0041] A make-up oil pump, the make-up oil pump is connected to the oil inlet of the variable control valve and is used to provide hydraulic oil for the variable control valve;

[0042] A main pump, the oil outlet of the main pump is connected to the first oil circuit, and the oil inlet of the main pump is connected to the second oil circuit;

[0043] A variable piston, connected to the oil outlet of the variable control valve, and is used to move under the drive of the hydraulic oil output by the variable control valve to adjust the displacement of the main pump;

[0044] The hydraulic drive system further includes a controller, configured to:

[0045] When the hydraulic motor is in the starting state, control the current of the variable control valve to gradually increase so that the displacement of the main pump increases;

[0046] When the pressure of the hydraulic oil in the first oil circuit exceeds the maximum working pressure of the system when the hydraulic motor is in the working state, control the current of the variable control valve to stop increasing so that the main pump stops increasing the displacement.

[0047] In an embodiment of the present invention, the pressure detection device is a pressure cut-off valve, and the hydraulic system further includes a hydraulic oil tank. The first end of the pressure cut-off valve is connected to the oil outlet of the main pump, the second end of the pressure cut-off valve is connected between the make-up oil pump and the variable control valve, and the third end of the pressure cut-off valve is connected to the hydraulic oil tank. The pressure cut-off valve is configured to connect the second end and the third end when the oil pressure at the oil outlet of the main pump exceeds the set pressure of the pressure cut-off valve, so as to divert the hydraulic oil in the oil circuit between the make-up oil pump and the variable control valve and reduce the pressure of the hydraulic oil input to the variable control valve; or

[0048] The pressure detection device is a pressure sensor, and the pressure sensor is arranged at the oil outlet of the main pump. The pressure sensor is configured to control the main pump to stop increasing the displacement when it detects that the oil pressure at the oil outlet of the main pump exceeds the maximum working pressure of the system.

[0049] In an embodiment of the present invention, the pressure regulating device further includes:

[0050] A second solenoid valve, and the second accumulator is connected to the first oil circuit through the second solenoid valve;

[0051] A third solenoid valve, and the second oil circuit is sequentially connected to the oil replenishing circuit of the make-up oil pump through the third solenoid valve and the cooler;

[0052] The controller is further configured to:

[0053] When the hydraulic motor is in the working state, control the second solenoid valve to open so that the second accumulator is connected to the first oil circuit; when the hydraulic motor is in the reworking state, control the third solenoid valve to open so that the second oil circuit is sequentially connected to the oil replenishing circuit of the make-up oil pump through the third solenoid valve and the cooler.

[0054] In an embodiment of the present invention, the pressure regulating device further includes:

[0055] A second pressure sensor, and the second pressure sensor is connected between the second accumulator and the second solenoid valve and is used to detect the working pressure between the second accumulator and the first oil circuit;

[0056] The controller is further configured to:

[0057] When the working pressure is less than the minimum working pressure, control the third solenoid valve to close so that the connection between the second oil circuit and the cooler is disconnected; and

[0058] Control the variable pump assembly to work. In an embodiment of the present invention, the pressure regulating device further includes:

[0059] A fourth solenoid valve;

[0060] The second accumulator is connected to the auxiliary working module of the crushing device through the fourth solenoid valve;

[0061] The controller is further configured to:

[0062] When the auxiliary working module is in the working state, control the fourth solenoid valve to open so that the second accumulator communicates with the auxiliary working module.

[0063] The second aspect of the present invention provides a material crushing vehicle, including the above hydraulic drive system.

[0064] By adopting the above hydraulic drive system, the system pressure is regulated by the pressure regulating device to effectively consume the excessive braking energy generated by the hydraulic motor when the hydraulic motor brakes, reduce the risk of shaft breakage of the output shaft of the hydraulic motor, avoid overheating damage of the variable pump assembly, and can also regulate the system pressure impact caused by the difference in the materials being crushed when the hydraulic motor is in the starting or operating state, absorb the pulse energy to smooth the acceleration or operation process of the hydraulic motor.

[0065] Other features and advantages of the present invention will be described in detail in the subsequent specific implementation section. BRIEF DESCRIPTION OF THE DRAWINGS

[0066] The drawings are used to provide a further understanding of the present invention and constitute a part of the specification, and are used to explain the present invention together with the following specific implementation, but do not constitute a limitation to the present invention. In the drawings:

[0067] Figure 1 Schematically shows the hydraulic drive system of the first embodiment of the present invention;

[0068] Figure 2 Schematically shows the hydraulic drive system of the second embodiment of the present invention.

[0069] DESCRIPTION OF THE REFERENCE NUMERALS

[0070] 220, variable pump assembly; 221, main pump; 222, variable piston; 223, variable control valve; 224, high-pressure relief valve; 225, low-pressure relief valve; 226, pressure cut-off valve; 277, make-up oil pump; 200, pressure regulating device; 209, pressure sensor; 201, first relief valve; 202, check valve; 203, throttle valve; 204, first accumulator; 205, third accumulator; 300, hydraulic motor; 601, speed sensor; 150, cutting tool disc; 271, filter; 262, cooler; 281, third solenoid valve; 282, first solenoid valve; 283, second solenoid valve; 284, fourth solenoid valve; 231, second accumulator; 242, second relief valve; 261, second pressure sensor. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0071] The specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are only for the purpose of illustrating and explaining the present invention, and are not intended to limit the present invention.

[0072] It should be noted that if there are directional indications (such as up, down, left, right, front, back...) involved in the embodiments of the present application, then such directional indications are only used to explain the relative positional relationship, movement conditions, etc. between components in a specific posture (as shown in the accompanying drawings). If this specific posture changes, then the directional indications will also change accordingly.

[0073] In addition, if there are descriptions involving "first", "second", etc. in the embodiments of the present application, then such descriptions of "first", "second", etc. are only for descriptive purposes, and cannot be understood as indicating or implying their relative importance or implicitly indicating the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include at least one such feature. In addition, the technical solutions between various embodiments can be combined with each other, but it must be based on the ability of those of ordinary skill in the art to implement. When the combination of technical solutions results in contradictions or cannot be implemented, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection required by the present application.

[0074] Figure 1 Schematically shows the hydraulic drive system of the first embodiment of the present invention; Figure 2 Schematically shows the hydraulic drive system of the second embodiment of the present invention. As Figure 1 and Figure 2 shown, in an embodiment of the present invention, a hydraulic drive system is provided. The hydraulic drive system can be applied to a crushing device. The hydraulic drive system includes:

[0075] A variable pump assembly 220;

[0076] A hydraulic motor 300 for driving the cutting tool disc 150 of the crushing device to work. The oil inlet of the hydraulic motor 300 is connected to the oil outlet of the variable pump assembly 220 through a first oil circuit, and the oil outlet of the hydraulic motor 300 is connected to the oil inlet of the variable pump assembly 220 through a second oil circuit;

[0077] A pressure regulating device 200, connected to the second oil circuit, for shunting the hydraulic oil in the second oil circuit to reduce the pressure of the hydraulic oil when the pressure of the hydraulic oil in the second oil circuit exceeds the maximum set pressure when the hydraulic motor 300 is in a braking state.

[0078] In this embodiment, it should be noted that the crushing device may include a feed hopper, a feed roller, a cutting cutter head 150 (cutter roller), a discharge pipe, a hydraulic drive system, etc. Blades are provided on the cutting cutter head 150, and it is driven to rotate by the hydraulic drive system to crush materials. The hydraulic drive system can provide power in ways such as taking power from the chassis gearbox, taking full power, or using a separate auxiliary engine. The oil inlet of the hydraulic motor 300 of the hydraulic drive system is connected to the oil outlet of the variable pump assembly 220 through the first oil circuit. After the variable pump assembly 220 obtains power, it can provide hydraulic oil for the hydraulic motor 300 according to actual working requirements to drive the hydraulic motor 300 to rotate. The hydraulic motor 300 is connected to the crushing device by means of a coupling, a transmission shaft, a flange, etc. When the hydraulic motor 300 rotates, it drives the cutting cutter head 150 to work. The oil outlet of the hydraulic motor 300 is connected to the oil inlet of the variable pump assembly 220 through the second oil circuit to return the hydraulic oil to the variable pump assembly 220 through this second oil circuit. The working hydraulic oil circulates in a closed loop in the pipeline of the hydraulic drive system to form a closed system.

[0079] The hydraulic motor 300 corresponds to different states under different working requirements. When the crushing device crushes materials, the hydraulic motor 300 is first in the starting state, the motor starts to rotate and the speed continuously increases to the working speed, and then enters the operating state to drive the cutting cutter head 150 to perform the crushing work. When the current material crushing is completed, the hydraulic motor 300 enters the braking state, and after the braking is completed, it enters the standby or shutdown state until the next material crushing when it enters the starting state again, the motor starts to rotate and the speed continuously increases to the working speed and enters the operating state again to drive the cutting cutter head 150 to perform the crushing work.

[0080] The pressure regulating device 200 can regulate the system pressure of the hydraulic drive system. When the hydraulic motor 300 is in the braking state, the displacement of the hydraulic oil output by the variable pump assembly 220 gradually decreases to 0 displacement to control the speed of the hydraulic motor 300 to gradually decrease. However, due to the large inertia characteristic of the hydraulic motor 300, its speed will not immediately decrease to 0. When the displacement of the hydraulic oil output by the variable pump assembly 220 decreases too fast and the slope is too large, the hydraulic oil output by the cutting cutter head 150 dragging the hydraulic motor 300 in reverse will exceed the requirement of the variable pump assembly 220. The pressure regulating device 200 is connected to the second oil circuit. When the pressure of the hydraulic oil in the second oil circuit exceeds the maximum set pressure when the hydraulic motor 300 is in the braking state, it shunts the hydraulic oil in the second oil circuit to reduce the pressure of the hydraulic oil, where the maximum set pressure is determined by the set pressure of the relief valve in the pressure regulating device. The pressure regulating device 200 can also be connected to the first oil circuit to regulate the system pressure shock caused by the difference in the materials being crushed when the hydraulic motor 300 is in the starting or operating state, and absorb the pulse energy to smooth the acceleration or operation process of the hydraulic motor 300.

[0081] By adopting the above hydraulic drive system, the system pressure is regulated by the pressure regulating device 200 to effectively consume the excessive braking energy generated by the hydraulic motor 300 when the hydraulic motor 300 brakes, reduce the risk of shaft breakage of the output shaft of the hydraulic motor 300, cool the hydraulic oil, avoid overheating damage of the variable pump assembly 220, and can also regulate the system pressure impact caused by the difference in the materials being crushed when the hydraulic motor 300 is in the starting or operating state, and absorb the pulse energy to smooth the acceleration or operation process of the hydraulic motor 300.

[0082] As Figure 1 shown, in the embodiment of the present invention, the pressure regulating device 200 includes:

[0083] A first overflow valve 201; a one-way valve 202; wherein, the first overflow valve 201 and the one-way valve 202 are connected in series between the first oil path and the second oil path, and the one-way valve 202 only allows the hydraulic oil to flow from the second oil path to the first oil path.

[0084] In the embodiment of the present invention, the hydraulic drive system further includes: a controller configured to: determine the braking mode of the hydraulic motor 300; in the case where the braking mode is an emergency stop mode, set the maximum allowable pressure of the first overflow valve 201 to a first pressure value; in the case where the braking mode is a non-emergency stop mode, set the maximum allowable pressure of the first overflow valve 201 to a second pressure value; wherein, the second pressure value is less than the first pressure value.

[0085] In this embodiment, it should be noted that the first overflow valve 201 can play a safety protection role in the system. When the system pressure exceeds the specified value, the safety valve in the first overflow valve 201 opens, discharging a part of the oil in the system into the first oil path, so that the system pressure does not exceed the allowable value, thereby ensuring that the system does not have an accident due to excessive pressure; the one-way valve 202 is used to prevent the oil flow from flowing reversely; in this embodiment, by connecting the first overflow valve 201 and the one-way valve 202 in series between the first oil path and the second oil path, the one-way valve 202 restricts the hydraulic oil from flowing from the second oil path connecting the oil outlet of the hydraulic motor 300 and the oil inlet of the variable pump assembly 220 to the first oil path, so that when the hydraulic motor 300 is in the braking state, the hydraulic oil in the second oil path can be shunted through the throttling and overflow functions of the first overflow valve 201 to reduce the pressure of the hydraulic oil input to the variable pump assembly 220.

[0086] The hydraulic motor 300 can set different braking modes according to different working conditions. In this embodiment, the braking modes of the hydraulic motor 300 include an emergency stop mode and a non-emergency stop mode. When the cutting head 150 needs to stop quickly, the hydraulic motor 300 enters the emergency stop mode. In the emergency stop mode, the controller sets the maximum allowable pressure value of the first relief valve 201 to a first pressure value, and this first pressure value is a relatively high pressure value, so that the pressure regulating device 200 can provide a larger braking torque to achieve rapid shutdown; when allowing the cutting head 150 to stop at medium or low speed, the hydraulic motor 300 enters the non-emergency stop mode. In the non-emergency stop mode, the controller sets the maximum allowable pressure value of the first relief valve 201 to a second pressure value, and this second pressure value is a relatively low pressure value to achieve pressure division of the hydraulic oil input to the variable pump assembly 220. The second pressure value is less than the first pressure value. In practical applications, the braking mode of the hydraulic motor 300 can be set to the emergency stop mode in case of emergency, and the braking mode of the hydraulic motor 300 can be set to the non-emergency stop mode in case of natural shutdown.

[0087] In the embodiment of the present invention, the pressure regulating device 200 further includes: a throttle valve 203 connected in series between the first relief valve 201 and the second oil circuit.

[0088] In this embodiment, it should be noted that the throttle valve 203 is a valve that can control the fluid flow rate. By connecting the throttle valve 203 in series between the first relief valve 201 and the second oil circuit, the throttling function of the throttle valve 203 is further used to consume the braking energy generated by the hydraulic motor 300.

[0089] In the embodiment of the present invention, the pressure regulating device 200 further includes: a first accumulator 204 connected to the second oil circuit.

[0090] In this embodiment, it should be noted that the accumulator is an energy storage device. It converts the energy in the system into compressed energy or potential energy and stores it at an appropriate time. When the system needs it, it converts the compressed energy or potential energy into hydraulic or pneumatic energy and releases it to replenish the system again. When the system pressure increases instantaneously, it can absorb this part of the energy to ensure the normal pressure of the entire system. In this embodiment, by connecting the first accumulator 204 to the second oil circuit, when the hydraulic motor 300 brakes, the first accumulator 204 absorbs the pulsating flow rate, reduces the braking pressure impact, and smooths the deceleration process.

[0091] In the embodiment of the present invention, the pressure regulating device 200 further includes:

[0092] A third accumulator 205 connected to the first oil circuit.

[0093] In this embodiment, it should be noted that the third accumulator 205 is connected to the first oil circuit and is used to adjust the system pressure shock caused by the difference in the materials being crushed when the hydraulic motor 300 is in the starting or operating state, and absorb the pulse energy to smooth the acceleration or operation process of the hydraulic motor 300.

[0094] As Figure 2 shown, in the embodiment of the present invention, the pressure regulating device 200 includes: a second accumulator 231; and a first solenoid valve 282; the second accumulator 231 is connected to the second oil circuit through the first solenoid valve 282; the hydraulic drive system further includes a controller configured to control the first solenoid valve 282 to open when the hydraulic motor 300 is in the braking state, so that the second accumulator 231 communicates with the second oil circuit.

[0095] In this embodiment, it should be noted that the solenoid valve controls the fluid, and the flow of hydraulic oil at both ends of the solenoid valve can be realized through the solenoid valve. Connecting the second accumulator 231 to the second oil circuit through the first solenoid valve 282 can store the energy of the second oil circuit by using the second accumulator 231 when the first solenoid valve 282 is opened. The controller controls the first solenoid valve 282 to open when the hydraulic motor 300 is in the braking state, so that a part of the hydraulic oil at the oil outlet of the hydraulic motor 300 flows into the accumulator, reducing the hydraulic oil pressure on the variable pump assembly 220 and also absorbing the pulsating flow based on the performance of the accumulator, reducing the braking pressure shock and smoothing the deceleration process of the cutter head.

[0096] In the embodiment of the present invention, the pressure regulating device 200 further includes: a second relief valve 242, the first end of the second relief valve 242 is connected to the second accumulator 231 and is used to set the maximum working pressure of the second accumulator 231;

[0097] The controller is further configured to: determine the braking mode of the hydraulic motor 300; in the case where the braking mode is the emergency stop mode, set the maximum allowable pressure of the second relief valve 242 to a first pressure value to set the maximum working pressure of the second accumulator 231 to a first maximum working pressure; in the case where the braking mode is a non-emergency stop mode, set the maximum allowable pressure of the second relief valve 242 to a second pressure value to set the maximum working pressure of the second accumulator 231 to a second maximum working pressure; wherein, the second pressure value is less than the first pressure value.

[0098] In the embodiment of the present invention, the variable pump assembly 220 includes a make-up oil pump 227; the hydraulic drive system further includes a cooler 262, and the second end of the second relief valve 242 is connected to the make-up oil circuit of the make-up oil pump 227 through the cooler 262.

[0099] In this embodiment, it should be noted that the second relief valve 242 can play a safety protection role in the system. When the system pressure exceeds the specified value, the safety valve in the second relief valve 242 is opened, and a part of the oil in the system is discharged into the oil replenishing circuit, so that the system pressure does not exceed the allowable value, thereby ensuring that the system does not have an accident due to excessive pressure. In this embodiment, by connecting the second relief valve 242 to the second accumulator 231, the maximum working pressure of the second accumulator 231 is set by using the limit of the second relief valve 242.

[0100] The hydraulic motor 300 can set different braking modes according to different working conditions. In this embodiment, the braking modes of the hydraulic motor 300 include an emergency stop mode and a non-emergency stop mode. When the cutting head 150 needs to stop quickly, the hydraulic motor 300 enters the emergency stop mode. In the emergency stop mode, the controller sets the maximum allowable pressure value of the second relief valve 242 to a first pressure value, and this first pressure value is a relatively high pressure value, so that the maximum working pressure of the second accumulator 231 is set to a first maximum working pressure, forming a relatively large oil return back pressure and absorbing more braking energy to achieve a quick stop. When allowing the cutting head 150 to stop at medium or low speed, the hydraulic motor 300 enters the non-emergency stop mode. In the non-emergency stop mode, the controller sets the maximum allowable pressure value of the second relief valve 242 to a second pressure value, and this second pressure value is a relatively low pressure value, so as to set the maximum working pressure of the second accumulator 231 to a second maximum working pressure to achieve pressure division of the hydraulic oil input to the variable pump assembly 220. The second pressure value is less than the first pressure value, and the second maximum working pressure is less than the first maximum working pressure. In practical applications, the braking mode of the hydraulic motor 300 can be set to the emergency stop mode in an emergency, and the braking mode of the hydraulic motor 300 can be set to the non-emergency stop mode in the case of natural shutdown.

[0101] When the hydraulic drive system forms a closed system, its structure is relatively compact. The speed change and direction change of the working mechanism are achieved by adjusting the variable mechanism of the pump or motor, avoiding the hydraulic shock and energy loss that occur during the direction change of the open system. However, since the hydraulic oil after the closed system finishes working does not return to the fuel tank, the heat dissipation and filtration conditions of the hydraulic oil are worse than those of the open system. To compensate for the leakage in the system, a small-capacity makeup oil pump is usually required for oil replenishment and heat dissipation. In this embodiment, a makeup oil pump 227 is provided in the variable pump assembly 220 to utilize the makeup oil pump 227 to form a makeup oil circuit to achieve oil replenishment and heat dissipation for the hydraulic drive system. The cooler 262 can be used to cool the fluid. By setting the cooler 262 at the second end of the second overflow valve 242, the second end of the second overflow valve 242 can be connected to the makeup oil circuit of the makeup oil pump 227 through the cooler 262, so that the hydraulic oil overflowing from the second overflow valve 242 when the second accumulator 231 reaches the maximum working pressure can enter the makeup oil circuit of the makeup oil pump 227 after being cooled, reducing the oil temperature of the hydraulic oil while reconnecting the hydraulic oil to the internal circulation of the hydraulic drive system.

[0102] In one embodiment, the variable pump assembly 220 may further include a low-pressure overflow valve 225, and the low-pressure overflow valve 225 is connected to the makeup oil pump 227, so that the hydraulic oil flowing out from the second end of the second overflow valve 242 and connected to the makeup oil circuit of the makeup oil pump 227 through the cooler 262 overflows into the hydraulic oil tank when the pressure reaches the set value of the low-pressure overflow valve 225.

[0103] As Figure 1 and Figure 2 shown, in the embodiment of the present invention, the variable pump assembly 220 includes: a pressure detection device for controlling the variable pump assembly 220 to stop increasing the displacement when it detects that the oil pressure at the oil outlet of the variable pump assembly 220 exceeds the maximum working pressure of the system.

[0104] In this embodiment, it should be noted that the maximum working pressure of the system refers to the maximum working pressure of the hydraulic drive system under normal working conditions. The rotation speed of the hydraulic motor 300 can be controlled by the hydraulic oil displacement of the variable pump assembly 220. When the displacement is large, the hydraulic oil flow output by the variable pump assembly 220 increases at a constant rotation speed, driving the rotation speed of the hydraulic motor 300 to increase. When the hydraulic motor 300 starts, the displacement of the variable pump assembly 220 will gradually increase until the hydraulic motor 300 enters the working rotation speed. The pressure detection device determines the working pressure of the current hydraulic drive system by detecting the oil pressure at the oil outlet of the variable pump assembly 220, and controls the variable pump assembly 220 to stop increasing the displacement when the oil pressure exceeds the maximum working pressure of the system until the working pressure of the hydraulic drive system drops below the normal maximum working pressure of the system, thereby avoiding power-stage overflow caused by system flow mismatch and reducing energy consumption.

[0105] In an embodiment of the present invention, the variable pump assembly 220 further includes: a variable control valve 223; a make-up oil pump 227 connected to an oil inlet of the variable control valve 223 for supplying hydraulic oil to the variable control valve 223; a main pump 221, an oil outlet of the main pump 221 is connected to a first oil circuit, and an oil inlet of the main pump 221 is connected to a second oil circuit; a variable piston 222 connected to an oil outlet of the variable control valve 223 for moving under the drive of the hydraulic oil output by the variable control valve 223 to adjust the displacement of the main pump 221;

[0106] The hydraulic drive system further includes a controller configured to: when the hydraulic motor 300 is in a starting state, gradually increase the current of the variable control valve 223 so that the displacement of the main pump 221 increases; when the pressure of the hydraulic oil in the first oil circuit exceeds the maximum working pressure of the system or the hydraulic motor 300 reaches the set working speed during the operation of the hydraulic motor 300, stop increasing the current of the variable control valve 223 to make the main pump 221 stop increasing the displacement.

[0107] In this embodiment, it should be noted that the oil outlet of the variable control valve 223 is connected to the variable piston 222, and the displacement of the main pump 221 can be adjusted by the movement of the variable piston 222. Among them, the linkage relationship between the variable piston 222 and the main pump 221 is known to those skilled in the art and will not be elaborated here. The make-up oil pump 227 is connected to the oil inlet of the variable control valve 223 for supplying hydraulic oil to the variable control valve 223. When the hydraulic motor 300 is in a starting state, the controller gradually increases the current of the variable control valve 223 so that the oil pressure at the oil outlet of the variable control valve 223 increases, pushing the variable piston 222 to move in the direction of large displacement, making the displacement of the main pump 221 increase; when the pressure of the hydraulic oil in the first oil circuit exceeds the maximum working pressure of the system during the operation of the hydraulic motor 300, stop increasing the current of the variable control valve 223, the oil pressure at the oil outlet of the variable control valve 223 is maintained, the oil pressure entering the cavity of the variable piston 222 is maintained, and the variable piston 222 stops moving to make the main pump 221 stop increasing the displacement. It can be understood that the hydraulic oil input by the make-up oil pump 227 to the variable control valve 223 is pilot hydraulic oil for controlling the variable pump assembly.

[0108] The make-up oil pump 227 is connected to the hydraulic oil tank, and a filter 271 is further provided between the oil suction port of the make-up oil pump 227 and the hydraulic oil tank to enable the make-up oil pump 227 to suck oil from the tank after filtration.

[0109] In an embodiment of the present invention, the pressure detection device is a pressure cut-off valve 226. The hydraulic drive system further includes a hydraulic oil tank. The first end of the pressure cut-off valve 226 is connected to the oil outlet of the main pump 221, and the second end of the pressure cut-off valve 226 is connected between the make-up oil pump 227 and the variable control valve 223. The pressure cut-off valve 226 is configured to connect the second end and the third end when the oil pressure at the oil outlet of the main pump 221 exceeds its set pressure, so as to divert the hydraulic oil in the oil circuit between the make-up oil pump 227 and the variable control valve 223, and reduce the pressure of the hydraulic oil input to the variable control valve 223; or the pressure detection device is a pressure sensor 209. The pressure sensor 209 is arranged at the oil outlet of the main pump 221 and is configured to control the main pump 221 to stop increasing the displacement when it detects that the oil pressure at the oil outlet of the main pump 221 exceeds the maximum working pressure of the system.

[0110] In this embodiment, it should be noted that the pressure cut-off valve 226 can be a combination of a relief valve and a shuttle valve. Among them, the port of the shuttle valve is the first end of the pressure cut-off valve 226, the end of the relief valve connected to the hydraulic oil circuit is the second end of the pressure cut-off valve 226, and the end of the relief valve connected to the hydraulic oil tank is the third end of the pressure cut-off valve 226; in this embodiment, the first end of the pressure cut-off valve 226 is connected to the oil outlet of the main pump 221, and the pressure of the current hydraulic drive system can be obtained through the pressure at the oil outlet of the main pump 221; the second end is connected between the make-up oil pump 227 and the variable control valve 223, so that when the oil pressure at the oil outlet of the main pump 221 exceeds the set pressure of the pressure cut-off valve 226, the second end and the third end of the pressure cut-off valve 226 are connected, so as to divert the hydraulic oil in the oil circuit between the make-up oil pump 227 and the variable control valve 223. Part of the hydraulic oil output by the make-up oil pump 227 is input to the hydraulic oil tank, reducing the pressure of the hydraulic oil input to the variable control valve 223 and reducing the control pressure on the variable piston 222 to reduce the displacement of the main pump 221. Specifically, the pressure cut-off valve 226 itself has a set pressure, which is greater than the maximum working pressure of the system. When the oil pressure at the oil outlet of the main pump 221 exceeds the maximum working pressure of the system and reaches this set pressure, the pressure cut-off valve 226 connects the make-up oil pump 227 through its second end and third end. The variable pump assembly 220 further includes two high-pressure relief valves 224. One high-pressure relief valve 224 is located between the make-up oil pump 227 and the oil outlet of the main pump 221, and the other high-pressure relief valve 224 is located between the make-up oil pump 227 and the oil inlet of the main pump 221, and can be used as a shock-proof valve. If the pressure of the hydraulic drive system rises to the set pressure of the high-pressure relief valve 224, the high-pressure relief valve 224 will overflow. If the hydraulic drive system overflows from here for a long time and the overflowing oil is overheated at this time, it will cause damage to the variable pump assembly 220. Therefore, the set pressure of the pressure cut-off valve 226 needs to be set to be less than the set pressure of the high-pressure relief valve 224.

[0111] In one embodiment, the pressure cut-off valve 226 may not be provided, and a pressure sensor 209 is provided at the oil outlet of the main pump 221. The pressure sensor 209 can detect the oil pressure at the oil outlet of the main pump 221 in real time and upload it to the controller. When the oil pressure at this oil outlet exceeds the maximum working pressure of the system, the controller controls the main pump 221 to stop increasing the displacement.

[0112] In one embodiment, the hydraulic drive system may further include a speed sensor 601 connected to the hydraulic motor 300. The speed sensor 601 detects the speed of the hydraulic motor 300 in real time and uploads it to the controller. When the controller monitors that the speed of the hydraulic motor 300 is 0 for several seconds after the working pressure of the hydraulic drive system has reached the maximum working pressure, it is determined that the cutting tool head 150 is jammed. At this time, the current of the variable control valve 223 is quickly returned to 0, or the pressure cut-off valve 226 acts automatically, so that the displacement of the main pump 221 returns to the 0 displacement position, avoiding power stage overflow loss and reducing energy consumption.

[0113] As Figure 2 shown, in the embodiment of the present invention, the pressure regulating device 200 further includes:

[0114] A second solenoid valve 283;

[0115] The second accumulator 231 is connected to the first oil circuit through the second solenoid valve 283;

[0116] A third solenoid valve 281;

[0117] The second oil circuit is sequentially connected to the oil replenishing circuit of the oil replenishing pump 227 through the third solenoid valve 281 and the cooler 262;

[0118] The controller is further configured to: when the hydraulic motor 300 is in the working state, control the second solenoid valve 283 to open so that the second accumulator 231 communicates with the first oil circuit; when the hydraulic motor 300 is in the reworking state, control the third solenoid valve 281 to open so that the second oil circuit sequentially passes through the third solenoid valve 281 and the cooler 262 and communicates with the oil replenishing circuit of the oil replenishing pump 227.

[0119] In the embodiment of the present invention, the pressure regulating device 200 further includes:

[0120] A second pressure sensor 261, which is connected between the second accumulator 231 and the second solenoid valve 283 and is used to detect the working pressure between the second accumulator 231 and the first oil circuit;

[0121] The controller is further configured to: when the working pressure is less than the minimum working pressure, control the third solenoid valve 281 to be turned off, so as to disconnect the connection between the second oil circuit and the cooler 262; and control the variable pump assembly 220 to operate.

[0122] In this embodiment, it should be noted that by setting the second accumulator 231 to be connected to the first oil circuit through the second solenoid valve 283, the controller can control the second solenoid valve 283 to open when the hydraulic motor 300 is in the working state, so that the second accumulator 231 is communicated with the first oil circuit, so that the second accumulator 231 adjusts the system pressure impact caused by the difference in the materials being crushed, absorbs the pulse energy to smooth the acceleration or working process of the hydraulic motor 300.

[0123] When the hydraulic motor 300 is in the re-operation state, in the previous operation state of the hydraulic motor 300, the second accumulator 231 has stored a part of the energy. At this time, the energy stored in the second accumulator 231 can be preferentially used as the hydraulic oil source for the re-operation state of the hydraulic motor 300. The second oil circuit is sequentially connected to the oil replenishing circuit of the oil replenishing pump 227 through the third solenoid valve 281 and the cooler 262. The controller can further control the third solenoid valve 281 to open when the hydraulic motor 300 is in the re-operation state. Since the second solenoid valve 283 is in the open state at this time, the second oil circuit is sequentially connected to the oil replenishing circuit of the oil replenishing pump 227 through the third solenoid valve 281 and the cooler 262, so that the hydraulic oil in the accumulator enters the oil inlet of the hydraulic motor 300 through the second solenoid valve 283, drives the hydraulic motor 300 to work, and makes the hydraulic oil output from the oil outlet of the hydraulic motor 300 enter the oil replenishing circuit of the oil replenishing pump 227 through the third solenoid valve 281 and the cooler 262. It should be noted that if the second accumulator 231 stores energy, when using the energy released by the second accumulator 231 to drive the hydraulic motor 300 to be in the working state, if the second solenoid valve 283 is in the closed state, the second solenoid valve 283 and the third solenoid valve 281 need to be opened simultaneously at this time.

[0124] Furthermore, the minimum working pressure refers to the minimum working pressure of the hydraulic drive system under normal working conditions. Since the energy stored in the second accumulator 231 is limited, when the energy of the second accumulator 231 is not enough to support the operation of the hydraulic motor 300, it is necessary to start the variable pump assembly 220 to operate. By setting the second pressure sensor 261 connected between the second accumulator 231 and the second solenoid valve 283 to detect the working pressure between the second accumulator 231 and the first oil circuit, the controller controls the third solenoid valve 281 to be turned off when the working pressure detected by the second pressure sensor 261 is less than the minimum working pressure, so as to disconnect the connection between the second oil circuit and the cooler 262, and control the variable pump assembly 220 to operate.

[0125] In an embodiment of the present invention, the pressure regulating device 200 further includes:

[0126] A fourth solenoid valve 284;

[0127] The second accumulator 231 is connected to the auxiliary working module of the crushing device through the fourth solenoid valve 284;

[0128] The controller is further configured to: control the fourth solenoid valve 284 to open when the auxiliary working module is in a working state, so that the second accumulator 231 communicates with the auxiliary working module.

[0129] In this embodiment, it should be noted that the auxiliary working module of the crushing device may include modules such as a feeding roller motor, a discharging oil cylinder, and a leg oil cylinder. The second accumulator 231 is connected to the auxiliary working module of the crushing device through the fourth solenoid valve 284. The controller controls the fourth solenoid valve 284 to open when the auxiliary working module is in a working state, so that the second accumulator 231 communicates with the auxiliary working module. By using the braking energy recovered by the second accumulator 231, the engine energy consumption can be reduced and the system energy efficiency can be improved.

[0130] Through the above hydraulic drive system, by setting a pressure cut-off valve 226 or based on a pressure sensor, the system pressure during the start-up or acceleration process of the hydraulic motor 300 is restricted, avoiding the situation where the high-pressure relief valve 224 overflows due to too high system pressure, resulting in overheating of the hydraulic oil temperature and too high temperature rise in the hydraulic circuit. By setting a throttle valve 203 and a relief valve or a second accumulator 231, the braking energy generated by the hydraulic motor 300 during braking is dynamically adjusted, reducing damage to the variable pump assembly 220, the hydraulic motor 300 and transmission parts. And by setting a first accumulator 204, a second accumulator 231, a second accumulator 231 and its solenoid valve group, the hydraulic circuit of the hydraulic drive system is leveled to suppress flow pulsation, reduce operation pressure shock and braking pressure shock, accelerate the braking process, recover and utilize braking energy, reduce energy consumption, and the braking energy can also be reused according to the storage capacity of the second accumulator 231, reducing engine energy consumption and improving system energy efficiency.

[0131] An embodiment of the present invention provides a material crushing vehicle, including the hydraulic drive system as described in the above embodiment.

[0132] In the description of the present invention, it should be noted that the orientation or positional relationship indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on the present invention. In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance. Among them, the terms "first position" and "second position" are two different positions, and the first feature being "above", "over" and "on" the second feature includes the first feature being directly above and obliquely above the second feature, or simply indicating that the first feature has a higher horizontal height than the second feature. The first feature being "under", "beneath" and "under" the second feature includes the first feature being directly below and obliquely below the second feature, or simply indicating that the first feature has a lower horizontal height than the second feature.

[0133] In the description of the present invention, it should be noted that unless otherwise clearly specified and limited, the terms "mounted", "connected" and "coupled" shall be construed broadly. For example, it may be a fixed connection, a detachable connection, or an integral connection; it may be a mechanical connection or an electrical connection; it may be directly connected or indirectly connected through an intermediate medium, and it may be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0134] It should also be noted that the term "comprising", "including" or any other variation thereof is intended to cover a non-exclusive inclusion, so that a process, method, commodity or device including a series of elements not only includes those elements but also includes other elements not expressly listed, or further includes elements inherent to such process, method, commodity or device. Without further limitation, the element defined by the phrase "comprising one..." does not exclude the existence of additional identical elements in the process, method, commodity or device including the element.

[0135] The above are only the embodiments of the present application and are not intended to limit the present application. For those skilled in the art, various changes and modifications can be made to the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included within the scope of the claims of the present application.

Claims

1. A hydraulic drive system, characterized in that, Applied to a crushing device, the hydraulic drive system includes: A variable pump assembly; A hydraulic motor for driving the cutting tool disc of the crushing device to work. The oil inlet of the hydraulic motor is connected to the oil outlet of the variable pump assembly through a first oil circuit, and the oil outlet of the hydraulic motor is connected to the oil inlet of the variable pump assembly through a second oil circuit; A pressure regulating device connected to the second oil circuit for diverting the hydraulic oil in the second oil circuit to reduce the pressure of the hydraulic oil when the pressure of the hydraulic oil in the second oil circuit exceeds the maximum set pressure when the hydraulic motor is in a braking state; The pressure regulating device includes a first overflow valve and a check valve. Among them, the first overflow valve and the check valve are connected in series between the first oil circuit and the second oil circuit, and the check valve only allows the hydraulic oil to flow from the second oil circuit to the first oil circuit; A controller configured to: Determine the braking mode of the hydraulic motor; When the braking mode is an emergency stop mode, set the maximum allowable pressure of the first overflow valve to a first pressure value; When the braking mode is a non-emergency stop mode, set the maximum allowable pressure of the first overflow valve to a second pressure value, where the second pressure value is less than the first pressure value.

2. The hydraulic drive system according to claim 1, characterized in that, The pressure regulating device further includes: A throttle valve connected in series between the first overflow valve and the second oil circuit.

3. The hydraulic drive system according to claim 1, wherein, The pressure regulating device further includes: A first accumulator connected to the second oil circuit.

4. The hydraulic drive system according to claim 1, wherein, The pressure regulating device includes: A second accumulator; and A first solenoid valve; The second accumulator is connected to the second oil circuit through the first solenoid valve; The hydraulic drive system further includes a controller configured to control the first solenoid valve to open when the hydraulic motor is in a braking state, so that the second accumulator is communicated with the second oil circuit.

5. The hydraulic drive system according to claim 4, characterized in that, The pressure regulating device further includes: A second overflow valve, the first end of the second overflow valve is connected to the second accumulator for setting the maximum working pressure of the second accumulator; The controller is further configured to: Determine the braking mode of the hydraulic motor; When the braking mode is an emergency stop mode, set the maximum allowable pressure of the second overflow valve to a first pressure value to set the maximum working pressure of the second accumulator to a first maximum working pressure; When the braking mode is a non-emergency stop mode, set the maximum allowable pressure of the second overflow valve to a second pressure value to set the maximum working pressure of the second accumulator to a second maximum working pressure; Wherein, the second pressure value is less than the first pressure value.

6. The hydraulic drive system according to claim 5, characterized in that, The variable pump assembly includes a make-up oil pump; The hydraulic drive system further includes a cooler, and the second end of the second overflow valve is connected to the make-up oil circuit of the make-up oil pump through the cooler.

7. The hydraulic drive system according to claim 1, characterized in that The pressure regulating device further includes: A third accumulator connected to the first oil circuit.

8. The hydraulic drive system according to claim 1, wherein The variable pump assembly includes: A pressure detection device for controlling the variable pump assembly to stop increasing the displacement when it detects that the oil pressure at the oil outlet of the variable pump assembly exceeds the maximum working pressure of the system.

9. The hydraulic drive system according to claim 8, wherein, The variable pump assembly further includes: A variable control valve; A make-up oil pump connected to the inlet port of the variable control valve for supplying hydraulic oil to the variable control valve; A main pump, the outlet port of the main pump is connected to the first oil circuit, and the inlet port of the main pump is connected to the second oil circuit; A variable piston connected to the outlet port of the variable control valve, configured to move under the drive of the hydraulic oil output by the variable control valve to adjust the displacement of the main pump; The hydraulic drive system further includes a controller configured to: When the hydraulic motor is in the starting state, control the current of the variable control valve to gradually increase so that the displacement of the main pump increases; When the hydraulic motor is in the working state and the pressure of the hydraulic oil in the first oil circuit exceeds the maximum working pressure of the system, control the current of the variable control valve to stop increasing so that the main pump stops increasing its displacement.

10. The hydraulic drive system according to claim 9, wherein The pressure detection device is a pressure cut-off valve, and the hydraulic drive system further includes a hydraulic oil tank, The first end of the pressure cut-off valve is connected to the outlet port of the main pump, the second end of the pressure cut-off valve is connected between the make-up oil pump and the variable control valve, the third end of the pressure cut-off valve is connected to the hydraulic oil tank, and the pressure cut-off valve is configured to connect the second end and the third end when the oil pressure at the outlet port of the main pump exceeds the set pressure of the pressure cut-off valve, so as to divert the hydraulic oil in the oil circuit between the make-up oil pump and the variable control valve and reduce the pressure of the hydraulic oil input to the variable control valve; or The pressure detection device is a pressure sensor provided at the outlet port of the main pump, and the pressure sensor is configured to control the main pump to stop increasing its displacement when it detects that the oil pressure at the outlet port of the main pump exceeds the maximum working pressure of the system.

11. The hydraulic drive system according to claim 6, characterized in that, The pressure regulating device further includes: A second solenoid valve, and the second accumulator is connected to the first oil circuit through the second solenoid valve; A third solenoid valve, and the second oil circuit is sequentially connected to the make-up oil circuit of the make-up oil pump through the third solenoid valve and the cooler; The controller is further configured to: When the hydraulic motor is in the working state, control the second solenoid valve to open so that the second accumulator is connected to the first oil circuit; when the hydraulic motor is in the re-working state, control the third solenoid valve to open so that the second oil circuit is sequentially connected to the make-up oil circuit of the make-up oil pump through the third solenoid valve and the cooler.

12. The hydraulic drive system according to claim 11, characterized in that, The pressure regulating device further includes: A second pressure sensor connected between the second accumulator and the second solenoid valve for detecting the working pressure between the second accumulator and the first oil circuit; The controller is further configured to: When the working pressure is less than the minimum working pressure, control the third solenoid valve to close so that the connection between the second oil circuit and the cooler is disconnected; and Control the variable pump assembly to work.

13. The hydraulic drive system according to claim 4, characterized in that, The pressure regulating device further includes: Fourth solenoid valve; The second accumulator is connected to an auxiliary working module of the crushing device through the fourth solenoid valve; The controller is further configured to: When the auxiliary working module is in a working state, control the fourth solenoid valve to open so that the second accumulator communicates with the auxiliary working module.

14. A material crushing vehicle, characterized in that, Comprising a hydraulic drive system according to any one of claims 1 to 13.

Images