Hydraulic system and working machine

Abstract

The utility model relates to the technical field of engineering machinery, and discloses a hydraulic system and an operation machine. The hydraulic system comprises a brake branch, an execution branch, a variable pump, an electromagnetic directional valve, an energy accumulator, a pressure detection component and a controller. A variable pump, a pressure detection part, an electromagnetic reversing valve and a first detection part are all electrically connected with a controller, and the controller controls the action of the electromagnetic reversing valve according to the pressure value, detected by the pressure detection part, in an energy accumulator and whether the first detection part on an execution branch detects an electric signal or not. Switching of the connection state between the variable pump and the brake branch or the execution branch is controlled, the variable pump can be selectively conducted with the brake branch and can also be selectively conducted with the execution branch, one pump is dual-purpose, the cost is low, the economical efficiency is good, meanwhile, the controller can adjust the displacement of the variable pump according to actual requirements, energy waste is avoided, and the service life of the variable pump is prolonged. And more energy is saved, and both energy conservation and economical efficiency are achieved.

Description

Technical Field

[0001] The utility model relates to the technical field of engineering machinery, in particular to a hydraulic system and an operating machinery. Background Art

[0002] The braking system of construction machinery is a critical component of the hydraulic system, crucial to the safety of the entire machine. A fully hydraulic braking system uses hydraulic oil to directly push the piston for braking, resulting in superior braking performance. Existing full hydraulic brake systems are categorized as fixed-displacement hydraulic systems and variable-displacement hydraulic systems. A full hydraulic brake system includes an accumulator connected to the brake assembly. However, since the pump displacement in a fixed-displacement hydraulic system is fixed, a large amount of oil will overflow through the relief valve when the brake accumulator is not filled, resulting in significant energy loss and poor energy-saving performance. A variable-displacement hydraulic system employs a load-sensing system, using a variable displacement pump that senses accumulator pressure via an LS (Load Senser) oil circuit to adjust the pump's displacement. This results in better energy-saving performance. However, due to the principle that accumulator pressure feedback is fed back to the variable displacement pump via the LS oil circuit, which then adjusts the pump's displacement, a variable-displacement hydraulic system can only be used for a single pump. That is, the variable displacement pump in a variable-displacement hydraulic system can only deliver hydraulic oil to the brake system. A separate pump is required to deliver hydraulic oil to the actuator system in addition to the brake system, preventing dual-use of the pump. This results in poor product economics.

[0003] Therefore, the hydraulic system in the prior art has the disadvantage of not being able to take into account both energy saving and economy. Utility Model Content

[0004] In view of this, the utility model provides a hydraulic system and an operating machine to solve the problem that the hydraulic system cannot take into account both energy saving and economy.

[0005] In the first aspect, the utility model provides a hydraulic system, comprising: a brake branch and an execution branch, wherein the brake branch is suitable for connecting a brake assembly, and the execution branch is suitable for connecting an execution element, and the execution element is provided with a first detection component; a variable pump, which delivers hydraulic oil to the brake branch or the execution branch; an electromagnetic reversing valve, which has an oil inlet, a first oil outlet and a second oil outlet, wherein the oil inlet is connected to the variable pump, the first oil outlet is connected to the brake branch, the second oil outlet is connected to the execution branch, and the first oil outlet can be selectively connected to the oil inlet The second oil outlet can be selectively connected to the oil inlet; the accumulator and the pressure detection component are connected to the brake branch, the accumulator is suitable for connecting to the brake assembly, and the pressure detection component is communicated with the accumulator to detect the pressure inside the accumulator; the controller is electrically connected to the variable pump, the pressure detection component, the electromagnetic reversing valve and the first detection component, and the controller is suitable for controlling the action of the electromagnetic reversing valve and adjusting the displacement of the variable pump according to the pressure detected by the pressure detection component and the electrical signal detected by the first detection component.

[0006] Beneficial effect: By setting the variable pump, pressure detection component, electromagnetic reversing valve and first detection component to be electrically connected with the controller, the pressure detection component is used to detect the pressure inside the accumulator in real time. The controller controls the action of the electromagnetic reversing valve according to the size of the pressure value detected by the pressure detection component and whether the first detection component on the execution branch detects the electrical signal. According to actual needs, the oil inlet of the electromagnetic reversing valve is switched to whether it is connected with the first oil outlet and the second oil outlet, thereby realizing the switching of the connection state between the variable pump and the brake branch or the execution branch. The variable pump can choose to be connected with the brake branch or the execution branch, realizing dual use of one pump with low cost and good economy. At the same time, the controller can also adjust the displacement of the variable pump according to actual needs, avoiding the problem of energy waste caused by the mismatch between the oil supply of the traditional quantitative pump and the actual demand, so it is more energy-saving, thereby achieving both energy saving and economy.

[0007] In an optional embodiment, the electromagnetic reversing valve is a three-position three-way valve, and the electromagnetic reversing valve includes a first working position, a second working position, and a closed position. When the electromagnetic reversing valve is in the first working position, the oil inlet is connected to the first oil outlet; when the electromagnetic reversing valve is in the second working position, the oil inlet is connected to the second oil outlet; when the electromagnetic reversing valve is in the closed position, the oil inlet is disconnected from both the first oil outlet and the second oil outlet.

[0008] The electromagnetic reversing valve is suitable for switching to the first working position when the pressure detected by the pressure detection component is less than a first preset pressure value, switching to the second working position when the first detection component detects an electrical signal and the pressure detected by the pressure detection component is greater than a second preset pressure value, and switching to the closed position when the pressure detected by the pressure detection component is greater than the second preset pressure value and the first detection component does not detect an electrical signal, wherein the first preset pressure value is less than the second preset pressure value.

[0009] Beneficial effect: by setting the electromagnetic reversing valve to have a first working position in which the oil inlet is connected to the first oil outlet, a second working position in which the oil inlet is connected to the second oil outlet, and a closed position in which the oil inlet is disconnected from the first oil outlet and the second oil outlet, the electromagnetic reversing valve is switched between different working positions and closed positions, so as to facilitate the connection or disconnection between the variable pump and different branches. On the one hand, the variable pump acts as a charging valve to ensure that the internal pressure of the accumulator is maintained at an appropriate level to ensure the reliability of the braking process. On the other hand, it acts as a working pump to provide the required hydraulic oil to the actuator. By setting the closed position of the middle position of the electromagnetic reversing valve to a fully closed position, when the displacement of the variable pump starts to increase from the minimum, the electromagnetic reversing valve in the closed position can play a role in holding back pressure, so that the variable pump can be pre-started.

[0010] In an optional embodiment, the hydraulic system further includes: an oil tank suitable for storing hydraulic oil, the variable pump being connected to the oil tank; a relief valve, the fluid inlet of the relief valve being connected to the pipeline between the variable pump and the electromagnetic reversing valve, and the fluid outlet of the relief valve being connected to the oil tank.

[0011] Beneficial effect: By setting a relief valve between the variable pump and the electromagnetic reversing valve, the relief valve opens when the system pressure exceeds the set value and discharges the excess oil back to the oil tank, thereby protecting the system from excessive pressure, protecting the variable pump from damage, and improving the safety of the system.

[0012] In an optional embodiment, the overflow valve is an electrically controlled overflow valve, which is electrically connected to the controller. The controller is suitable for adjusting the overflow pressure of the overflow valve to a first overflow pressure value when the electromagnetic reversing valve is in the first working position, and the controller is suitable for adjusting the overflow pressure of the overflow valve to a second overflow pressure value when the electromagnetic reversing valve is in the second working position, wherein the first overflow pressure value is greater than the second overflow pressure value.

[0013] Beneficial effect: By setting the overflow valve as an electrically controlled overflow valve and electrically connecting it to the controller, the controller can adjust the overflow pressure of the overflow valve according to the state of the electromagnetic reversing valve, so that the overflow pressure of the overflow valve can match the different overflow pressure requirements of the braking branch and the execution branch, thereby ensuring that the overflow valve acts as a safety valve to protect the variable pump from damage.

[0014] In an optional embodiment, the brake assembly includes a hydraulic brake caliper, and the brake branch also includes: a brake pedal valve, the fluid inlet of the brake pedal valve is connected to the accumulator, the fluid outlet of the brake pedal valve is connected to the hydraulic brake caliper, the brake pedal valve has a conduction state in which the fluid inlet and the fluid outlet of the brake pedal valve are connected, and a cut-off state in which the fluid inlet and the fluid outlet of the brake pedal valve are disconnected, and the brake pedal valve is suitable for switching between the conduction state and the cut-off state.

[0015] Beneficial effect: By setting the brake pedal valve's fluid inlet to be connected with the accumulator and its fluid outlet to be connected with the hydraulic brake caliper, and the brake pedal valve having a conducting state in which its fluid inlet and its fluid outlet are connected, and a cut-off state in which its fluid inlet and its fluid outlet are partially connected, the accumulator and the hydraulic brake caliper can be switched between the conducting state and the cut-off state by switching the brake pedal valve between the conducting state and the cut-off state. When the accumulator and the hydraulic brake caliper are connected through the brake pedal valve, the oil in the accumulator directly enters the hydraulic brake caliper to drive the hydraulic brake caliper to operate, thereby achieving braking, convenient operation and high reliability.

[0016] In an optional embodiment, the brake assembly also includes a parking brake cylinder, and the brake branch also includes: a switching valve, the fluid inlet of the switching valve is connected to the accumulator, the fluid outlet of the switching valve is connected to the parking brake cylinder, the switching valve also has an oil unloading port, the oil unloading port of the switching valve is connected to the oil tank, and the oil outlet of the switching valve can be selectively connected to the oil inlet of the switching valve or the oil unloading port of the switching valve.

[0017] Beneficial effect: By arranging a switch valve upstream of the parking brake cylinder, the switch valve controls whether the brake branch delivers hydraulic oil to the parking brake cylinder, thereby achieving control of the parking brake with a high degree of automation and high reliability.

[0018] In an optional embodiment, the electromagnetic reversing valve, the overflow valve and the switch valve are integrated into an integrated valve block.

[0019] Beneficial effect: By integrating the electromagnetic reversing valve, relief valve and switch valve into an integrated valve block, the number of pipelines in the hydraulic system can be reduced, the structure is simplified, the layout is convenient, and the overall occupied space is reduced.

[0020] In an optional embodiment, the hydraulic system further includes: a filter, the filter is connected to the pipeline between the variable pump and the electromagnetic reversing valve, and the liquid inlet of the overflow valve is connected to the pipeline between the filter and the electromagnetic reversing valve.

[0021] Beneficial effect: By setting a filter to filter the hydraulic oil output from the variable pump, impurities can be reduced, thereby reducing damage to various components in the hydraulic system, which is beneficial to extending the service life and improving safety.

[0022] In an optional embodiment, the pressure detection component is a pressure sensor.

[0023] Beneficial effects: The pressure sensor has a simple structure, high reliability, is easy to obtain and has low cost.

[0024] In a second aspect, the present invention further provides an operating machine comprising: the above-mentioned hydraulic system. Since the operating machine comprises a hydraulic system, it has the same effects as the hydraulic system and will not be described in detail here. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the specific implementation methods of the utility model or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0026] Figure 1 This is a structural diagram of a hydraulic system according to an embodiment of the present utility model;

[0027] Figure 2 for Figure 1 A partial enlarged schematic diagram of the integrated valve block portion of the hydraulic system shown in FIG;

[0028] Figure 3 It is a structural diagram of a traditional quantitative braking system;

[0029] Figure 4 Schematic diagram of the structure of a traditional load-sensing braking system.

[0030] Description of reference numerals:

[0031] 1. Variable pump; 101. Dosing pump; 102. Dual-way filling valve; 2. Filter; 3. Integrated valve block; 4. Parking brake cylinder; 5. Switch valve; 6. Accumulator; 7. Pressure detection component; 8. Brake pedal valve; 9. Hydraulic brake caliper; 10. Solenoid reversing valve; 110. First working position; 120. Second working position; 130. Closed position; 11. Overflow valve; 12. Action execution system; 13. Fuel tank; 21. Brake branch; 22. Execution branch. DETAILED DESCRIPTION

[0032] To make the purpose, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the embodiments described are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without making creative efforts shall fall within the scope of protection of the present invention.

[0033] The hydraulic systems of operating machinery in the existing market are mainly divided into quantitative systems, single-variable systems and dual-variable systems. Among them, the braking system is one of the most important systems in the hydraulic system, which is related to the safety of the entire machine. At present, hydraulic braking systems are generally divided into air-over-oil dry systems and full-hydraulic wet systems. The air-over-oil dry braking system is mainly used in operating machinery with relatively small tonnage. Its characteristics are good stability under general working conditions, but it is greatly affected by compressed air; the full-hydraulic braking system has better braking effect than the air-over-oil system because the hydraulic oil directly pushes the piston for braking, so it is widely used in large-scale operating machinery, but the disadvantage is that the structure is complex and the maintenance cost is high.

[0034] There are two ways to charge the accumulator in the full hydraulic braking system: one is the quantitative braking system, and the other is the load sensing system. Figure 3 As shown, this is a quantitative braking system. When working, the hydraulic oil enters the dual-way filling valve 102 from the quantitative pump 101, and the oil brakes the brake disc by pushing the hydraulic brake caliper 9. An accumulator 6 is installed on the pipeline between the dual-way filling valve 102 and the hydraulic brake caliper 9. When the accumulator 6 needs to be filled, the oil enters the accumulator 6 after passing through the dual-way filling valve 102. When it is not filled, the oil enters the pilot oil source block through the O port to provide oil for the pilot action. Figure 4As shown, this is a load-sensitive braking system. The oil in the variable pump 1 enters the dual-way charging valve 102 and then enters the accumulator 6. The difference between the load-sensitive braking system and the quantitative braking system is that the load-sensitive system senses the pressure inside the accumulator 6 through the LS oil circuit, thereby adjusting the displacement of the variable pump 1 to achieve energy saving. Specifically, when the pressure in the accumulator 6 reaches a predetermined low value, the LS is fed back to the variable pump 1, and the displacement of the variable pump 1 increases, filling the accumulator 6 until the predetermined high value of the accumulator 6 is reached.

[0035] Since the displacement of the pump of the quantitative braking system is fixed, it will cause a lot of energy loss in the non-liquid-filled state, and its energy-saving performance is poor; the variable braking system uses a variable pump, so it has better energy-saving performance, but the variable pump of the load-sensitive system can only be used alone, and as a product, it has poor economy.

[0036] The following combination Figures 1 to 2 , describing the embodiments of the present utility model.

[0037] According to an embodiment of the present invention, on the one hand, a hydraulic system is provided, including: a brake branch 21, an execution branch 22, a variable pump 1, an electromagnetic reversing valve 10, an accumulator 6, a pressure detection component 7 and a controller. The brake branch 21 is suitable for connecting the brake assembly, and the execution branch 22 is suitable for connecting the execution element, and the execution element is provided with a first detection component; the variable pump 1 delivers hydraulic oil to the brake branch 21 or the execution branch 22; the electromagnetic reversing valve 10 has an oil inlet, a first oil outlet and a second oil outlet, the oil inlet is connected to the variable pump 1, the first oil outlet is connected to the brake branch 21, and the second oil outlet is connected to the execution branch 22, the first oil outlet can be selectively connected to the oil inlet, and the second oil outlet can be selectively connected to the oil inlet; the accumulator 6 and the pressure detection component 7 are connected to the brake branch 21, the accumulator 6 is suitable for connecting the brake assembly, and the pressure detection component 7 is connected to the accumulator 6 to detect the pressure inside the accumulator 6; the controller is electrically connected to the variable pump 1, the pressure detection component 7, the electromagnetic reversing valve 10 and the first detection component, and the controller is suitable for controlling the action of the electromagnetic reversing valve 10 and adjusting the displacement of the variable pump 1 according to the pressure detected by the pressure detection component 7 and the electrical signal detected by the first detection component. Among them, the braking branch 21 is connected in parallel with the execution branch 22; the oil inlet of the electromagnetic reversing valve 10 can be connected to the first oil outlet or the second oil outlet, or neither the first oil outlet nor the second oil outlet is connected to the oil inlet.

[0038] The hydraulic system of the present embodiment is electrically connected to the controller by setting the variable pump 1, the pressure detection component 7, the electromagnetic reversing valve 10 and the first detection component. The pressure detection component 7 is used to detect the pressure inside the accumulator 6 in real time. The controller controls the action of the electromagnetic reversing valve 10 according to the size of the pressure value detected by the pressure detection component 7 and whether the first detection component on the execution branch 22 detects the electrical signal. According to actual needs, the oil inlet of the electromagnetic reversing valve 10 is switched to whether it is connected with the first oil outlet and the second oil outlet, thereby realizing the switching of the connection state between the variable pump 1 and the brake branch 21 or the execution branch 22. The variable pump 1 can choose to be connected with the brake branch 21 or the execution branch 22, realizing dual use of one pump with low cost and good economy. At the same time, the controller can also adjust the displacement of the variable pump 1 according to actual needs, avoiding the problem of energy waste caused by the mismatch between the oil supply of the traditional quantitative pump and the actual demand, thereby being more energy-saving, thereby achieving both energy saving and economy.

[0039] It should be noted that by using a variable pump, the hydraulic system is a variable hydraulic system, and the controller fully electronically controls the electromagnetic reversing valve 10 and the variable pump 1. Compared with the traditional variable hydraulic system, the hydraulic system of this embodiment removes the LS oil circuit feedback, simplifies the hydraulic system structure, further reduces the cost, and has a high degree of automation.

[0040] It should be noted that the electrical signals detected by the first detection component include but are not limited to temperature signals, pressure signals, angle signals, proximity switch limit signals, and oil level sensor signals.

[0041] In one embodiment, the electromagnetic reversing valve 10 is a three-position three-way valve, and the electromagnetic reversing valve 10 includes a first working position 110, a second working position 120 and a closed position 130. When the electromagnetic reversing valve 10 is in the first working position 110, the oil inlet is connected to the first oil outlet; when the electromagnetic reversing valve 10 is in the second working position 120, the oil inlet is connected to the second oil outlet; when the electromagnetic reversing valve 10 is in the closed position, the oil inlet is disconnected from both the first oil outlet and the second oil outlet; the electromagnetic reversing valve 10 is suitable for switching to the first working position 110 when the pressure detected by the pressure detection component 7 is less than the first preset pressure value, switching to the second working position 120 when the first detection component detects an electrical signal and the pressure detected by the pressure detection component 7 is greater than the second preset pressure value, and switching to the closed position 130 when the pressure detected by the pressure detection component 7 is greater than the second preset pressure value and the first detection component does not detect an electrical signal, wherein the first preset pressure value is less than the second preset pressure value.

[0042] It should be noted that the first preset pressure value and the second preset pressure value are pre-set fixed values, and the first preset pressure value is less than the second preset pressure value. When the pressure inside the accumulator 6 detected by the pressure detection component 7 is less than the first preset pressure value, the internal pressure of the accumulator 6 is too small, and the hydraulic oil in the accumulator 6 is insufficient. At this time, the accumulator 6 needs to be filled. By switching the electromagnetic reversing valve 10 to the first working position 110, the oil inlet of the electromagnetic reversing valve 10 is connected to the first oil outlet, and the conduction between the variable pump 1 and the brake branch 21 is realized. The electromagnetic reversing valve 10 serves as a charging valve to realize the variable pump 1 to deliver hydraulic oil to the accumulator 6; when the pressure inside the accumulator 6 detected by the pressure detection component 7 is greater than the second preset pressure value, the hydraulic oil in the accumulator 6 is sufficient, and the internal pressure of the accumulator 6 reaches the braking requirement. If the first detection component detects an electrical signal at the same time, it indicates that the actuator is working. By switching the electromagnetic reversing valve 10 to the second working position 120, the oil inlet and the second oil outlet are connected, and the variable pump 1 is connected to the execution branch 22, the variable pump 1 delivers hydraulic oil to the execution branch 22, driving the actuator on the execution branch 22 to work. If the pressure inside the accumulator 6 detected by the pressure detection component 7 is greater than the second preset pressure value, the first detection component does not detect an electrical signal, the actuator does not work, and there is no need to deliver hydraulic oil to the execution branch 22. The electromagnetic reversing valve 10 is switched to the closed position 130, the oil inlet is disconnected from both the first and second oil outlets, and the variable pump 1 is neither connected to the brake branch 21 nor to the execution branch 22. In this way, the electromagnetic reversing valve 10 can achieve priority braking control.

[0043] By setting the electromagnetic reversing valve 10 to have a first working position 110 in which the oil inlet is connected to the first oil outlet, a second working position 120 in which the oil inlet is connected to the second oil outlet, and a closed position 130 in which the oil inlet is disconnected from the first oil outlet and the second oil outlet, the electromagnetic reversing valve 10 is switched between different working positions and closed positions, so as to facilitate the connection or disconnection between the variable pump 1 and different branches. On the one hand, the variable pump 1 acts as a charging valve to ensure that the internal pressure of the accumulator 6 is maintained at an appropriate level to ensure the reliability of the braking process. On the other hand, it acts as a working pump to provide the required hydraulic oil to the actuator. By setting the closed position 130 of the middle position of the electromagnetic reversing valve 10 to a fully closed position, when the displacement of the variable pump 1 starts to increase from the minimum, the electromagnetic reversing valve 10 in the closed position 130 can play a pressure-holding role, so that the variable pump 1 can be pre-started.

[0044] In one embodiment, the hydraulic system further includes an oil tank 13 and a relief valve 11. The oil tank 13 is suitable for storing hydraulic oil, and the variable pump 1 is connected to the oil tank 13. The inlet of the relief valve 11 is connected to the pipeline between the variable pump 1 and the solenoid reversing valve 10, and the outlet of the relief valve 11 is connected to the oil tank 13. By providing the relief valve 11 between the variable pump 1 and the solenoid reversing valve 10, the relief valve 11 opens when the system pressure exceeds a set value, draining excess oil back to the oil tank 13. This protects the system from excessive pressure, protects the variable pump 1 from damage, and improves system safety.

[0045] In one embodiment, the relief valve 11 is an electrically controlled relief valve. The relief valve 11 is electrically connected to a controller. The controller is adapted to adjust the relief pressure of the relief valve 11 to a first relief pressure value when the electromagnetic reversing valve 10 is in the first working position 110, and to adjust the relief pressure of the relief valve 11 to a second relief pressure value when the electromagnetic reversing valve 10 is in the second working position 120. The first relief pressure value is greater than the second relief pressure value. It should be noted that when the electromagnetic reversing valve 10 is in the first working position 110, the variable pump 1 is charging the accumulator 6. At this time, the relief valve 11 needs to be set to a higher relief pressure to prevent the pressure setting of the relief valve 11 from being lower than the charging pressure during the charging process, thereby causing system overflow. When the electromagnetic reversing valve 10 is in the second working position 120, it indicates that the accumulator 6 has completed charging. At this time, the relief pressure of the relief valve 11 should be reduced to restore the relief pressure of the execution branch 22. By setting the overflow valve 11 as an electrically controlled overflow valve and electrically connecting it to the controller, the controller can adjust the overflow pressure of the overflow valve 11 according to the state of the electromagnetic reversing valve 10, so that the overflow pressure of the overflow valve 11 can match the different overflow pressure requirements of the braking branch 21 and the execution branch 22, thereby ensuring that the overflow valve 11 acts as a safety valve to protect the variable pump 1 from damage.

[0046] In addition, in other embodiments, the relief valve 11 may also be a pilot relief valve. The use of the pilot relief valve can also achieve the effect of serving as a safety valve to protect the variable pump 1 from damage.

[0047] In one embodiment, a brake assembly includes a hydraulic brake caliper 9, and a brake branch circuit 21 further includes a brake pedal valve 8. The inlet of the brake pedal valve 8 is connected to the accumulator 6, and the outlet of the brake pedal valve 8 is connected to the hydraulic brake caliper 9. The brake pedal valve 8 has an on state, in which the inlet and outlet of the brake pedal valve 8 are connected, and an off state, in which the inlet and outlet of the brake pedal valve 8 are disconnected. The brake pedal valve 8 is adapted to switch between the on state and the off state. It should be noted that the hydraulic brake caliper 9 is used for braking during driving. When the working machine is not braking, the brake pedal valve 8 is in the off state, and there is no communication between the accumulator 6 and the hydraulic brake caliper 9. When the working machine is braking, the brake pedal drives the brake pedal valve 8 to switch to the on state, connecting the accumulator 6 and the hydraulic brake caliper 9, thereby allowing hydraulic oil in the accumulator 6 to enter the hydraulic brake caliper 9.

[0048] By setting the liquid inlet of the brake pedal valve 8 to be connected with the accumulator 6 and the liquid outlet to be connected with the hydraulic brake caliper 9, and the brake pedal valve 8 has a conductive state in which its liquid inlet and its liquid outlet are connected, and a cut-off state in which its liquid inlet and its liquid outlet are partially connected, the accumulator 6 and the hydraulic brake caliper 9 can be switched between the conductive state and the cut-off state by switching the brake pedal valve 8 between the conductive state and the cut-off state. When the accumulator 6 and the hydraulic brake caliper 9 are connected through the brake pedal valve 8, the oil in the accumulator 6 directly enters the hydraulic brake caliper 9 to drive the hydraulic brake caliper 9 to operate, thereby achieving braking, convenient operation and high reliability.

[0049] In one embodiment, the brake assembly also includes a parking brake cylinder 4, and the brake branch 21 also includes: a switch valve 5, the liquid inlet of the switch valve 5 is connected to the accumulator 6, the liquid outlet of the switch valve 5 is connected to the parking brake cylinder 4, the switch valve 5 also has an oil unloading port, the oil unloading port of the switch valve 5 is connected to the oil tank 13, and the oil outlet of the switch valve 5 can be selectively connected to the liquid inlet of the switch valve 5 or the oil unloading port of the switch valve 5. It should be noted that the parking brake cylinder 4 is used for braking after parking. The parking brake cylinder 4 includes a rod chamber and a rodless chamber. The liquid outlet of the switch valve 5 is connected with the rodless chamber of the parking brake cylinder 4 through a pipeline. During the driving process of the operating machinery, the oil outlet of the switch valve 5 is connected with the oil unloading port of the switch valve 5, and the hydraulic oil in the parking brake cylinder 4 flows back to the oil tank 13 through the oil unloading port of the switch valve 5; when the operating machinery is parked, the switch valve 5 is switched to connect the oil outlet and the oil inlet, and the hydraulic oil in the brake branch flows to the parking brake cylinder 4 to realize parking braking.

[0050] By arranging a switch valve 5 upstream of the parking brake cylinder 4, the switch valve 5 controls whether the brake branch 21 delivers hydraulic oil to the parking brake cylinder 4, thereby achieving control of the parking brake with a high degree of automation and high reliability.

[0051] Specifically, when the switch valve 5 is switched to the state where the oil inlet and the oil outlet are connected, the accumulator 6 in the brake branch 21 is connected to the rodless chamber of the parking brake cylinder 4, and the parking brake is achieved by delivering hydraulic oil to the rodless chamber.

[0052] In one embodiment, the brake pedal valve 8 includes two valve bodies, each valve body corresponds to a hydraulic brake caliper 9, the number of parking brake cylinders 4 is two, the number of accumulators 6 is three, and the parking brake cylinder 4 and each brake pedal valve 8 are connected to one accumulator 6.

[0053] In one embodiment, the solenoid directional control valve 10, the relief valve 11, and the on-off valve 5 are integrated into an integrated valve block 3. This integration of the solenoid directional control valve 10, the relief valve 11, and the on-off valve 5 reduces the number of pipelines in the hydraulic system, simplifies the structure, facilitates layout, and reduces the overall space occupied. Specifically, a pressure detection component 7 is provided at port C of the integrated valve block 3 to detect the pressure within the accumulator 6.

[0054] In addition, in other embodiments, the hydraulic valves in the integrated valve block 3 can also be used separately without affecting the functions of the individual hydraulic valves.

[0055] In one embodiment, the hydraulic system further includes a filter 2 connected to the pipeline between the variable pump 1 and the electromagnetic reversing valve 10. The fluid inlet of the relief valve 11 is connected to the pipeline between the filter 2 and the electromagnetic reversing valve 10. Filter 2 is disposed downstream of the fluid outlet of the variable pump 1. By providing filter 2 to filter the hydraulic oil output from the variable pump 1, impurities can be reduced, thereby reducing damage to various components in the hydraulic system, extending their service life, and improving safety.

[0056] In one embodiment, the pressure detection component 7 is a pressure sensor, which has a simple structure, high reliability, is easy to obtain, and has a low cost.

[0057] The operating logic and process of the hydraulic system of this embodiment are listed as follows:

[0058] 1) When the pressure detected by the pressure detection component 7 is lower than the first preset value, the variable pump 1 needs to charge the accumulator 6. At this time, the electromagnetic pressure of the relief valve 11 is increased to the first relief pressure value to prevent the pressure setting of the relief valve 11 from being lower than the charging pressure during the charging process, thereby causing the system to overflow; when the accumulator 6 is being charged, the S1 electromagnet of the electromagnetic reversing valve 10 is energized, causing the valve core to move to the right, and the electromagnetic reversing valve 10 is switched to the first working position 110, so that the oil inlet and the first oil outlet are connected.

[0059] 2) When the pressure detected by the pressure detection component 7 is greater than the second preset value, it indicates that the accumulator 6 has completed filling. At this time, the S1 electromagnet of the electromagnetic reversing valve 10 is de-energized, the valve core moves to the left, and the electromagnetic reversing valve 10 switches to the closed position 130, cutting off the filling pipeline, reducing the overflow pressure of the overflow valve 11 to the second overflow pressure value, and restoring the overflow pressure of the action execution system 12.

[0060] 3) When in the non-liquid-filled state, when the actuator in the action execution system 12 needs to act, the S2 electromagnet of the electromagnetic reversing valve 10 is energized, the valve core moves to the left, and the electromagnetic reversing valve 10 switches to the second working position 120. The action execution system 12 directly feeds back the electrical signal detected by the first detection component to the controller, and the controller controls the variable pump 1 to change the displacement. Among them, the variable pump 1 is an inverse proportional variable pump, and the controller controls the current of the inverse proportional variable pump to decrease, thereby increasing the displacement of the variable pump 1, and the actuator acts.

[0061] 4) When the pressure of the accumulator 6 is lower than the first preset value and needs to be filled and the actuator in the action execution system 12 needs to be actuated, the electromagnetic reversing valve 10 will first execute S1 to be energized, so that the electromagnetic reversing valve 10 switches to the first working position 110 to carry out the accumulator 6 filling process; when the filling process is completed, that is, the pressure detected by the pressure detection component 7 is greater than the second preset value, S2 of the electromagnetic reversing valve 10 is energized, the electromagnetic reversing valve 10 switches to the second working position 120, and the execution process of the action execution system 12 is carried out.

[0062] In the hydraulic system of this embodiment, a variable pump 1 can be used to deliver hydraulic oil to the brake branch 21 or the execution branch 22, realizing dual use of one pump and effectively saving system costs; by adopting fully electronic control logic, the logic control of braking first and then other actions is met, which facilitates the control of the system, increases safety and greatly simplifies the system layout and piping arrangement.

[0063] According to an embodiment of the present invention, in another aspect, a working machine is provided, comprising: the above-mentioned hydraulic system, wherein the working machine includes a loader, an excavator, a crane, a bulldozer, etc.

[0064] Although the embodiments of the present invention have been described with reference to the accompanying drawings, those skilled in the art may make various modifications and variations without departing from the spirit and scope of the present invention, and such modifications and variations shall fall within the scope defined by the appended claims.

Claims

1. A hydraulic system, characterized in that: include: A braking branch (21) and an execution branch (22), wherein the braking branch (21) is suitable for connecting a braking assembly, and the execution branch (22) is suitable for connecting an execution element, and the execution element is provided with a first detection component; A variable displacement pump (1) delivers hydraulic oil to the brake branch (21) or the execution branch (22); The electromagnetic reversing valve (10) has an oil inlet, a first oil outlet, and a second oil outlet, wherein the oil inlet is connected to the variable pump (1), the first oil outlet is connected to the brake branch (21), and the second oil outlet is connected to the execution branch (22). The first oil outlet can be selectively connected to the oil inlet, and the second oil outlet can be selectively connected to the oil inlet. An accumulator (6) and a pressure detection component (7) are connected to the brake branch (21), the accumulator (6) is suitable for connecting to the brake assembly, and the pressure detection component (7) is connected to the accumulator (6) to detect the pressure inside the accumulator (6); A controller is electrically connected to the variable pump (1), the pressure detection component (7), the electromagnetic reversing valve (10) and the first detection component, and the controller is suitable for controlling the operation of the electromagnetic reversing valve (10) and adjusting the displacement of the variable pump (1) based on the pressure detected by the pressure detection component (7) and the electrical signal detected by the first detection component.

2. The hydraulic system according to claim 1, characterized in that The electromagnetic reversing valve (10) is a three-position, three-way valve. The electromagnetic reversing valve (10) includes a first working position (110), a second working position (120), and a closed position (130). When the electromagnetic reversing valve (10) is in the first working position (110), the oil inlet is connected to the first oil outlet; when the electromagnetic reversing valve (10) is in the second working position (120), the oil inlet is connected to the second oil outlet; when the electromagnetic reversing valve (10) is in the closed position (130), the oil inlet is disconnected from both the first oil outlet and the second oil outlet. The electromagnetic reversing valve (10) is adapted to switch to the first working position (110) when the pressure detected by the pressure detecting component (7) is less than a first preset pressure value, switch to the second working position (120) when the first detecting component detects an electrical signal and the pressure detected by the pressure detecting component (7) is greater than a second preset pressure value, and switch to the closed position (130) when the pressure detected by the pressure detecting component (7) is greater than the second preset pressure value and the first detecting component does not detect an electrical signal, wherein the first preset pressure value is less than the second preset pressure value.

3. The hydraulic system according to claim 2, characterized in that The hydraulic system further comprises: An oil tank (13) is suitable for storing hydraulic oil, and the variable displacement pump (1) is connected to the oil tank (13); A relief valve (11), wherein the liquid inlet of the relief valve (11) is connected to the pipeline between the variable pump (1) and the electromagnetic reversing valve (10), and the liquid outlet of the relief valve (11) is communicated with the oil tank (13).

4. The hydraulic system according to claim 3, characterized in that The overflow valve (11) is an electrically controlled overflow valve. The overflow valve (11) is electrically connected to the controller. The controller is suitable for adjusting the overflow pressure of the overflow valve (11) to a first overflow pressure value when the electromagnetic reversing valve (10) is in the first working position (110). The controller is suitable for adjusting the overflow pressure of the overflow valve (11) to a second overflow pressure value when the electromagnetic reversing valve (10) is in the second working position (120), wherein the first overflow pressure value is greater than the second overflow pressure value.

5. The hydraulic system according to claim 4, characterized in that The brake assembly includes a hydraulic brake caliper (9), and the brake branch (21) further includes: A brake pedal valve (8), wherein the fluid inlet of the brake pedal valve (8) is connected to the accumulator (6), and the fluid outlet of the brake pedal valve (8) is connected to the hydraulic brake caliper (9). The brake pedal valve (8) has an on-state in which the fluid inlet and the fluid outlet of the brake pedal valve (8) are connected, and a off-state in which the fluid inlet and the fluid outlet of the brake pedal valve (8) are disconnected. The brake pedal valve (8) is suitable for switching between the on-state and the off-state.

6. The hydraulic system according to claim 5, characterized in that The brake assembly further comprises a parking brake cylinder (4), and the brake branch (21) further comprises: A switch valve (5), wherein the liquid inlet of the switch valve (5) is communicated with the accumulator (6), the liquid outlet of the switch valve (5) is communicated with the parking brake cylinder (4), the switch valve (5) further comprises an oil discharge port, the oil discharge port of the switch valve (5) is communicated with the oil tank (13), and the oil outlet of the switch valve (5) can be selectively communicated with the oil inlet of the switch valve (5) or the oil discharge port of the switch valve (5).

7. The hydraulic system according to claim 6, characterized in that The electromagnetic reversing valve (10), the overflow valve (11) and the switch valve (5) are integrated into an integrated valve block (3).

8. The hydraulic system according to claim 3, characterized in that The hydraulic system further comprises: a filter (2), the filter (2) being connected to the pipeline between the variable pump (1) and the electromagnetic reversing valve (10), and the liquid inlet of the overflow valve (11) being connected to the pipeline between the filter (2) and the electromagnetic reversing valve (10).

9. The hydraulic system according to any one of claims 1 to 8, characterized in that: The pressure detection component (7) is a pressure sensor.

10. A working machine, characterized in that: include: The hydraulic system according to any one of claims 1 to 9.

Images