Hydraulic control system of sweeping mechanism of motor sweeper

Abstract

The invention relates to a hydraulic control system of a sweeping mechanism of a motor sweeper, and belongs to the technical field of fluid pressure executing mechanisms. The system comprises an oil tank, a hydraulic pump, a pair of sweeper hydraulic motors, a pair of sweeper expansion oil cylinders and a pair of sweeper lifting oil cylinders, wherein the sweeper hydraulic motors are respectively connected with the hydraulic pump and the oil tank to form a sweeper hydraulic motor control loop; the sweeping expansion oil cylinder is communicated with the hydraulic pump and the oil tank to form a sweeping expansion oil cylinder control loop, and a rodless cavity of the sweeping expansion oil cylinder is provided with a spring; the sweeper lifting oil cylinder is communicated with the hydraulic pump and the oil tank to form a sweeper lifting oil cylinder control loop; an electric proportional pressure reducing valve is arranged on the sweeping brush lifting oil cylinder control loop and is communicated with a rodless cavity of the sweeping brush lifting oil cylinder; and an outlet of the hydraulic pump is respectively connected with a first seat valve and a second seat valve which are connected in parallel. The system can generate extra ground contact pressure on the sweeper, the hydraulic system is prevented from being impacted and damaged when the sweeper touches a hard object, and the sweeper can rotate bidirectionally and can distribute the oil output of the pump.

Description

Technical Field

[0001] The invention relates to a hydraulic control system of a sweeping brush mechanism of a sweeper, and belongs to the technical field of fluid pressure actuators. Background Art

[0002] With the continuous advancement of domestic urbanization, people's requirements for the cleanliness of the urban environment and roads are getting higher and higher, which has led to an increasing market demand for road sweepers.

[0003] The sweeping brushes of existing sweepers still have the following problems: 1. When cleaning some heavily polluted roads or clearing snow in winter, the road surface cannot be cleaned completely only by the ground pressure generated by the weight of the sweeping mechanism.

[0004] 2. When the hydraulically controlled horizontally expanded sweeping brush hits a hard object, the sweeping brush hydraulic system is damaged due to the hard impact because the liquid is incompressible.

[0005] 3. The sweeping brush usually only rotates relatively inward and cannot rotate outward for sweeping.

[0006] 4. The flow distribution of the sweeping hydraulic system to the hydraulic cylinder and hydraulic motor cannot meet their respective required flow. Summary of the Invention

[0007] The technical problems to be solved by the present invention are: first, how to enable the hydraulic system of the sweeping brush mechanism to generate additional ground contact pressure on the sweeping brush; second, how to prevent the sweeping brush hydraulic system from being damaged due to hard impact when encountering hard objects; third, how to enable the sweeping brush to rotate in both directions; and fourth, how to evenly distribute the pumped oil to the needs of the hydraulic cylinder and hydraulic motor.

[0008] The present invention proposes a technical solution to solve the above-mentioned first technical problem: a hydraulic control system for a sweeping brush mechanism of a sweeper, comprising a fuel tank, a hydraulic pump, a pair of sweeping brush hydraulic motors, a pair of sweeping brush extension cylinders, and a pair of sweeping brush lifting cylinders; The liquid flow inlet and the liquid flow outlet of the sweeping hydraulic motor are respectively connected to the outlet of the hydraulic pump and the oil tank to form a sweeping hydraulic motor control circuit; The sweeping brush extension cylinder is connected to the hydraulic pump and the oil tank through a first reversing valve to form a sweeping brush extension cylinder control circuit. The first reversing valve is respectively connected to the rodless chamber and the rod chamber of the sweeping brush extension cylinder; The sweep brush lifting cylinder is connected to the hydraulic pump and the oil tank through a second reversing valve to form a sweep brush lifting cylinder control circuit, and the second reversing valve is connected to the rod chamber of the sweep brush lifting cylinder; An electric proportional pressure reducing valve is provided on the control circuit of the sweep brush lifting cylinder, and the electric proportional pressure reducing valve is connected to the rodless chamber of the sweep brush lifting cylinder; A second hydraulically controlled one-way valve is provided between the second reversing valve and the rod chamber of the sweeping and brushing lifting cylinder; A third seat valve is provided on the sweeping hydraulic motor control circuit, and the third seat valve is connected to the sweeping hydraulic motor and the hydraulic pump respectively. The normal state of the third seat valve is cut off, and it becomes connected when the coil is energized; The outlet of the hydraulic pump is connected to a first seat valve, and the outlet of the hydraulic pump is also connected to one port on the same side of the first reversing valve, the second reversing valve and the electric proportional pressure reducing valve respectively. The outlet of the first seat valve is connected to the other port on the same side of the first reversing valve, the second reversing valve and the electric proportional pressure reducing valve respectively; the other port on the same side of the first reversing valve, the second reversing valve and the electric proportional pressure reducing valve are all connected to the oil tank; the first seat valve is normally connected, and becomes cut off after the coil is energized.

[0009] In order to solve the above-mentioned second technical problem, the present invention improves the above-mentioned technical solution by: replacing the sweeping brush extension cylinder with a hydraulic single-acting cylinder, the rod chamber of the sweeping brush extension cylinder is connected to the first reversing valve and connected to the sweeping brush extension cylinder control circuit, and a spring is installed inside the rodless chamber of the sweeping brush extension cylinder; the first reversing valve is connected to the rod chamber of the sweeping brush extension cylinder; and a first hydraulically controlled one-way valve is added between the pair of sweeping brush extension cylinders and the first reversing valve.

[0010] In order to solve the third technical problem mentioned above, the second improvement to the above technical solution is: a third reversing valve is added to the liquid inlet and liquid outlet of the pair of hydraulic motors; one port on the same side of the third reversing valve is connected to the outlet of the third seat valve, and the other port on the same side of the third reversing valve is connected to the oil tank.

[0011] In order to solve the fourth technical problem mentioned above, the present invention provides the third improvement to the above technical solution: cancel the third seat valve, add a flow regulating distribution valve and a second seat valve; the outlet of the hydraulic pump is connected to the inlet of the flow regulating distribution valve; the flow regulating distribution valve has two outlets, one of which is connected to the sweeping brush hydraulic motor, and the other is connected to the sweeping brush extension cylinder and the sweeping brush lifting cylinder respectively; the outlet of the second seat valve is connected to the oil tank; the normal state of the second seat valve is connected, and it becomes the cut-off state after the coil is energized.

[0012] Furthermore, the first reversing valve, the second reversing valve and the third reversing valve are all electromagnetic reversing valves, the first seat valve and the second seat valve are electromagnetic valves, the middle positions of the first reversing valve and the second reversing valve are O type, and the middle position of the third reversing valve is M type.

[0013] Furthermore, outlet 1 of the flow regulating distribution valve is connected to the liquid inlet port of the third reversing valve; outlet 2 of the flow regulating distribution valve is respectively connected to a port on the same side of the first reversing valve, the second reversing valve and the electric proportional pressure reducing valve and is simultaneously connected to the liquid inlet port of the second seat valve.

[0014] Furthermore, the first seat valve is connected in parallel with a first overflow valve, the second seat valve is connected in parallel with a second overflow valve, and the first reversing valve and the first hydraulically controlled one-way valve are connected in parallel with a third overflow valve.

[0015] The beneficial effects of the present invention are as follows: 1) Since an electric proportional pressure reducing valve is provided in the control circuit of the sweep brush lifting cylinder, in addition to the existing reliance on the sweep brush mechanism to touch the ground by its own gravity, the downward pressure of the sweep brush mechanism is additionally increased by extending the rod of the sweep brush lifting cylinder, and the ground pressure of the sweep brush mechanism can be controlled by adjusting the current of the electric proportional pressure reducing valve; 2) Since a spring is provided in the rodless cavity of the sweep brush extension cylinder, the sweep brush extension cylinder only forms a hydraulic single action in the rod cavity. In this way, when the rod of the sweep brush extension cylinder is compressed due to the sweep brush hitting a hard object, the spring in the rodless cavity of the sweep brush extension cylinder is released. It will absorb the pressure of the compressed rod, thereby avoiding the impact on the sweeping brush extension cylinder control circuit and even the entire hydraulic system; 3) Since the sweeping brush hydraulic motor control circuit is provided with a third reversing valve, the rotation direction of a pair of sweeping brush hydraulic motors can be changed in both positive and negative directions through the third reversing valve, thereby adapting to the cleaning needs of different occasions; 4) Since the flow regulating distribution valve is connected to the outlet of the hydraulic pump, the flow of the hydraulic pump to the sweeping brush hydraulic motor control circuit and the sweeping brush extension cylinder control circuit and the sweeping brush lifting cylinder control circuit is adjusted and distributed, thereby adapting to the needs of hydraulic oil flow in different hydraulic control circuits. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The hydraulic control system of the sweeping brush mechanism of a sweeper of the present invention will be further described below with reference to the accompanying drawings.

[0017] Figure 1 This is a flow chart of a hydraulic control system of a sweeping brush mechanism of a sweeper according to Example 1; Figure 2 This is a flow chart of a hydraulic control system of a sweeping brush mechanism of a sweeper according to Example 2; Figure 3 This is a flow chart of a hydraulic control system of a sweeping brush mechanism of a sweeper according to Example 3; Figure 4 This is a flow chart of a hydraulic control system of a sweeping brush mechanism of a sweeper according to Example 4; Figure 5 yes Figure 4 Diagram of the middle sweeping brush extension cylinder and sweeping brush lifting cylinder with the rod extended.

[0018] Figure 6yes Figure 5 The middle sweeping brush hydraulic motor is in the first rotation state.

[0019] Figure 7 yes Figure 5 The middle sweeping brush hydraulic motor is in the second rotation state.

[0020] Figure 8 of Figure 5 Diagram of the middle sweep brush extension cylinder and sweep brush lift cylinder with the rod retracted. DETAILED DESCRIPTION Example 1

[0021] A hydraulic control system of a sweeping brush mechanism of a sweeper of this embodiment, such as Figure 1 As shown, it includes an oil tank 1, a hydraulic pump 2, a pair of sweeping brush hydraulic motors 3, 4, a pair of sweeping brush extension cylinders 5, 6 and a pair of sweeping brush lifting cylinders 7, 8.

[0022] like Figure 1 As shown, the fluid inlet and fluid outlet of the sweeping hydraulic motors 3 and 4 are respectively connected to the outlet of the hydraulic pump 2 and the oil tank 1 to form a sweeping hydraulic motor control circuit.

[0023] like Figure 1 As shown, the sweeping brush extension cylinders 5 and 6 are connected to the hydraulic pump 2 and the oil tank 1 through the first reversing valve 9 to form a sweeping brush extension cylinder control circuit. The first reversing valve 9 is respectively connected to the rodless cavity and the rod cavity of a pair of sweeping brush extension cylinders 5 and 6.

[0024] like Figure 1 As shown, the sweeping brush lifting cylinders 7 and 8 are connected to the hydraulic pump 2 and the oil tank 1 through the second reversing valve 10 to form a sweeping brush lifting cylinder control circuit. The second reversing valve 10 is connected to the rod chambers of the sweeping brush lifting cylinders 7 and 8.

[0025] like Figure 1 As shown, an electric proportional pressure reducing valve 11 is provided on the sweeping brush lifting cylinder control circuit, and the electric proportional pressure reducing valve 11 is connected to the rodless chambers of the sweeping brush lifting cylinders 7 and 8.

[0026] like Figure 1 As shown, a third seat valve 22 is provided on the sweeping hydraulic motor control circuit, and the third seat valve 22 is connected to the sweeping hydraulic motor 3 and the hydraulic pump 2 respectively.

[0027] like Figure 1As shown, the outlet of the hydraulic pump 2 is connected to a first seat valve 15 and a third seat valve 22. The outlet of the hydraulic pump 2 is also connected to one port P on the same side of the first reversing valve 9, the second reversing valve 10, and the electric proportional pressure-reducing valve 11. The outlet of the first seat valve 15 is connected to the other port T on the same side of the first reversing valve 9, the second reversing valve 10, and the electric proportional pressure-reducing valve 11. The outlet of the third seat valve 22 is connected to port A of the hydraulic motor 3. The other ports T on the same side of the first reversing valve 9, the second reversing valve 10, and the electric proportional pressure-reducing valve 11 are all connected to the oil tank 1. Port A of the hydraulic motor 4 is connected to the oil tank 1. In this embodiment, the first reversing valve 9 and the second reversing valve 10 are both solenoid reversing valves; the first seat valve 15 and the third seat valve 22 are also solenoid valves.

[0028] like Figure 1 As shown, the first seat valve 15 controls the on-off connection between the outlet of the hydraulic pump 2 and the hydraulic oil tank 1. When the coil of the first seat valve 15 is de-energized and normally open, the hydraulic oil at the outlet of the hydraulic pump 2 flows directly back to the hydraulic oil tank 1. When the coil of the first seat valve 15 is energized, it switches to a one-way throttle valve, preventing the hydraulic oil at the outlet of the hydraulic pump 2 from directly flowing back to the hydraulic oil tank 1. The hydraulic oil flows into the sweeping hydraulic motor control circuit, the sweeping extension cylinder control circuit, and the sweeping lifting cylinder control circuit, forming hydraulic pressure at the inlet of the third seat valve 22, as well as forming hydraulic pressure at the same-side port P of each of the first reversing valve 9, the second solenoid reversing valve 10, and the electric proportional pressure reducing valve 11.

[0029] The middle position of the first reversing valve 9 and the second reversing valve 10 is O-type, the normal state of the first seat valve 15 is connected, and the normal state of the third seat valve 22 is cut off.

[0030] like Figure 1 As shown, the first seat valve 15 is connected in parallel with a first overflow valve 18 .

[0031] The operating principle of the electro-proportional pressure reducing valve 11 is as follows: Under normal conditions, the coil of the electro-proportional pressure reducing valve 11 is de-energized. Under the action of its spring, the two ports A and T on opposite sides of the valve 11 are connected. At this point, the brush contact pressure is primarily generated by the weight of the brush mechanism (brush lift cylinder and brush). To increase the contact pressure, the coil of the electro-proportional pressure reducing valve 11 is energized, connecting the two ports A and P on opposite sides of the valve 11. The oil pump 2 drives hydraulic oil through the two ports A and P on opposite sides of the electro-proportional pressure reducing valve 11 into the rodless chambers of the brush lift cylinders 7 and 8, increasing the pressure within these chambers. Simultaneously, the left coil of the second solenoid reversing valve 10 is energized, causing the hydraulic oil in the rodless chambers of the brush lift cylinders 7 and 8 to leak into the oil tank 1. The rods of the brush lift cylinders 7 and 8 extend further, causing the brush mechanism to move downward further, thereby increasing the brush contact pressure. Because port A of the electro-proportional pressure-reducing valve 11 is connected to the right side of its spool, when the sum of the hydraulic pressure at port A and the spring force exceeds the thrust of the solenoid coil pushing the spool, the spool of the electro-proportional pressure-reducing valve 11 begins to move leftward, and ports A and T on the opposite side are connected again, causing overflow, with the overflowed hydraulic oil returning to tank 1. The greater the coil current of the electro-proportional pressure-reducing valve 11, the greater the hydraulic pressure required to move its spool leftward, that is, the greater the hydraulic pressure at port A. This, in turn, increases the pressure in the rodless chambers of the pair of sweep brush lift cylinders 7 and 8 connected to port A, and the brush contact pressure increases accordingly. Example 2

[0032] like Figure 2 As shown, this embodiment is a further improvement based on the embodiment 1. In addition to being the same as the embodiment 1, the difference is that: A pair of sweeping brush extension cylinders 5 and 6 are replaced with hydraulic single-acting cylinders. The rod chambers of the pair of sweeping brush extension cylinders 5 and 6 are connected to the first reversing valve and connected to the sweeping brush extension cylinder control circuit. A spring 21 is installed inside the rodless chambers of the pair of sweeping brush extension cylinders 5 and 6.

[0033] like Figure 2 As shown, a spring 21 is installed inside the rodless cavity of a pair of sweeping brush extension cylinders 5 and 6 of this embodiment. The advantage of this is that when cleaning garbage under harsh working conditions, the sweeping brush mechanism may collide with a hard obstacle, and the rod in the rod cavity is compressed to form pressure. At this time, the compression of the spring 21 can be used to buffer and absorb the pressure formed by the compression of the rod, thereby avoiding damage to the sweeping brush mechanism due to direct collision.

[0034] like Figure 1 、 2As shown, a first hydraulically controlled one-way valve 13 is installed between the first reversing valve 9 and the rod chambers of the sweep brush extension cylinders 5 and 6. A third relief valve 21 is connected in parallel to the first reversing valve 9 and the first hydraulically controlled one-way valve 13. A second hydraulically controlled one-way valve 14 is also installed between the second reversing valve 10 and the rod chambers of the sweep brush lift cylinders 7 and 8. The valve cores of the first and second hydraulically controlled one-way valves 13 and 14 are both cone valve structures, which effectively prevent hydraulic oil leakage in the rod chambers of the sweep brush extension cylinders 5 and 6 and the sweep brush lift cylinders 7 and 8, thereby preventing the sweep brush mechanism from falling to the ground while the sweeper is driving. Example 3

[0035] like Figure 3 As shown, this embodiment is a further improvement based on embodiment 2. In addition to being the same as embodiment 2, the difference is that: A third reversing valve 12 is added to the liquid inlet and liquid outlet of a pair of hydraulic motors 3 and 4. Port P of the third reversing valve 12 is connected to the outlet of the third seat valve 22, and port T of the third reversing valve 12 is connected to the oil tank 1.

[0036] like Figure 3 As shown, when the coil of the third seat valve 22 is energized, it changes from a cut-off state to a connected state. At the same time, the right coil of the third reversing valve 12 is energized (the valve core moves to the left), port P is connected to port A, and port B is connected to port T. At this time, the pair of hydraulic motors 3 and 4 both rotate inward.

[0037] Similarly, when the coil of the third seat valve 22 is energized, it changes from a cut-off state to a connected state. At the same time, the left coil of the third reversing valve 12 is energized (the valve core moves to the right), port P is connected with port B, and port A is connected with port T. At this time, the pair of hydraulic motors 3 and 4 rotate outward.

[0038] The third reversing valve 12 is an electromagnetic reversing valve, and its middle position is M-type. Example 4

[0039] like Figure 4 As shown, this embodiment is a further improvement on the basis of embodiment 3. In addition to being the same as embodiment 3, the differences are: the third seat valve 22 is eliminated, and a flow regulating distribution valve 17 and a second seat valve 16 are added; the outlet of the hydraulic pump 2 is connected to the inlet ① of the flow regulating distribution valve 17; the flow regulating distribution valve 17 has two outlets ② and ③, wherein the outlet 1 ② is connected to the sweeping brush hydraulic motors 3 and 4, and the outlet 2 ③ is connected to the sweeping brush extension cylinders 5 and 6 and the sweeping brush lifting cylinders 7 and 8 respectively.

[0040] like Figure 4 As shown, the second seat valve 16 is a solenoid valve, which is normally connected and becomes cut off when the coil is energized; the liquid inlet port of the second seat valve 16 is connected to the outlet 2 ③ of the flow regulating distribution valve; the liquid outlet port of the second seat valve 16 is connected to the oil tank 1.

[0041] like Figure 4 As shown, the second overflow valve 19 is connected in parallel with the second seat valve 16 .

[0042] The specific use process of the hydraulic control system of the sweeping brush mechanism of a sweeper of this embodiment is as follows.

[0043] like Figure 4 As shown, when the sweeper is not performing cleaning operations, the electromagnetic coils of the first reversing valve 9, the second solenoid reversing valve 10, the electric proportional pressure reducing valve 11 and the third reversing valve 12 are not energized, the valve cores of each valve group are in the initial state, the pair of sweeping brush motors 3 and 4 do not rotate, and the pair of sweeping brush extension cylinders 5 and 6 and the pair of sweeping brush lifting cylinders 7 and 8 are in the retracted state.

[0044] Generally, when the sweeper is in operation, it is necessary to first extend a pair of sweep brush extension cylinders 5, 6 and a pair of sweep brush lifting cylinders 7, 8, and then start a pair of sweep brush hydraulic motors 3, 4 to rotate a pair of sweep brushes.

[0045] like Figure 5As shown, after hydraulic pump 2 is started, the coil of first seat valve 15 is energized, switching the connected state to the blocked state. The hydraulic oil at the outlet of hydraulic pump 2 is diverted to ports 2 and 3 via port 1 of flow distribution control valve 17. The hydraulic oil at port 2 returns to hydraulic oil tank 1 via ports P and T of third solenoid reversing valve 12. The coil of second seat valve 16 is energized, switching the connected state to the blocked state. The high-pressure hydraulic oil at port 3 of flow distribution control valve 17 enters ports P on the same side of the first solenoid reversing valve 9, second solenoid reversing valve 10, and electric proportional pressure reducing valve 11. At this time, the left coil of the first solenoid reversing valve 9 is energized (the valve core moves to the right), and port ④ of the first hydraulically controlled one-way valve 13 is connected to the two ports B and P on the opposite sides of the first solenoid reversing valve 9. Under the action of high-pressure oil, the first hydraulically controlled one-way valve 13 changes from a cut-off state to a connected state, and port ⑥ of the first hydraulically controlled one-way valve 13 flows to port ⑤ and is connected to the two ports A and T on the opposite sides of the first solenoid reversing valve 9. The hydraulic oil in the rod chamber of a pair of sweeping brush extension cylinders 5 and 6 returns to the hydraulic oil tank 1 through the first hydraulically controlled one-way valve 13 and the first solenoid reversing valve 9 under the action of the compression spring 21 inside the rodless chamber. The rods of a pair of sweeping brush extension cylinders 5 and 6 are extended, and the cleaning width is increased. At the same time, the left coil of the second solenoid reversing valve 10 is energized (the valve core moves to the right). Port ⑦ of the second hydraulically controlled check valve 14 is connected to ports B and P on opposite sides of the second solenoid reversing valve 10. Acting upon the high-pressure oil, the second hydraulically controlled check valve 14 switches from a closed state to a connected state. Port ⑨ of the second hydraulically controlled check valve 14 flows to port ⑧ and connects to ports A and T on opposite sides of the second solenoid reversing valve 10. Simultaneously, the coil of the electric proportional pressure reducing valve 11 is energized, connecting ports P and A on opposite sides of the electric proportional pressure reducing valve 11. Oil flows into the rodless chambers of the pair of sweep and lift cylinders 7 and 8 through the electric proportional pressure reducing valve 11. The hydraulic oil in the rod chambers of the pair of sweep and lift cylinders 7 and 8 returns to the oil tank 1 through the second hydraulically controlled check valve 14 and the second solenoid reversing valve 10.

[0046] like Figure 6 As shown, after the rods of the sweep brush extension cylinders 5, 6 and the sweep brush lifting cylinders 7, 8 are fully extended, the right coil of the third electromagnetic reversing valve 12 is energized (the valve core moves to the left), and the port ② of the flow regulating distribution valve 17 is connected to the opposite side ports P and A of the third electromagnetic reversing valve 12. The hydraulic oil passes through the ports A and B of the left sweep brush motor 3, and then through the ports B and A of the right sweep brush motor 4, and returns to the oil tank 1. At this time, the left sweep brush rotates clockwise and the right sweep brush rotates counterclockwise. Sweep the garbage on the road to the middle of the vehicle, and use the suction nozzle and fan to suck the garbage into the garbage bin. According to the degree of pollution on the road, it can be divided into two working conditions: First, when the sweeper is cleaning garbage on conventional roads or low-pollution roads, it can directly use the gravity of the sweeping brush mechanism to generate ground contact pressure for cleaning operations, without increasing the sweeping brush ground contact pressure through the electric proportional pressure reducing valve 11.

[0047] Secondly, when the road sweeper is cleaning garbage or stubborn stains on heavily polluted roads, the electric proportional pressure reducing valve 11 can be used to increase the pressure of the sweeping brush touching the ground. The greater the coil current of the electric proportional pressure reducing valve 11, the greater the pressure of the sweeping brush touching the ground, and the cleaner the ground will be after cleaning.

[0048] When it is necessary to improve the cleanliness of road cleaning by increasing the pressure of the sweeping brush on the ground, it is recommended to replace the sweeping brush with a sweeping brush made of steel wire, which is more wear-resistant and the bristles are not easy to deform.

[0049] like Figure 7 As shown, the left coil of the third solenoid reversing valve 12 is energized (moving the valve core to the right), connecting port ② of the flow control distribution valve 17 to ports P and B on the opposite sides of the third solenoid reversing valve 12. Hydraulic oil then flows through ports A and B of the right sweeping brush motor 4, then through ports B and A of the left sweeping brush motor 3, returning to the fuel tank 1. At this point, the left sweeping brush rotates counterclockwise, while the right sweeping brush rotates clockwise, adapting to the snow-covered road conditions of the road sweeper, clearing the snow to both sides of the vehicle. When the road is heavily snowed, increasing the current in the coil of the electric proportional pressure reducing valve 11 increases the brush contact pressure, improving the cleanliness of the cleaned surface.

[0050] like Figure 8 As shown, in general, after stopping operation, the sweeper must first stop the brush rotation (stop the pair of brush hydraulic motors 3 and 4), then retract the pair of brush extension cylinders 5 and 6 and the pair of brush lifting cylinders 7 and 8. This de-energizes the coil of the third solenoid reversing valve 12, and the valve core of the third solenoid reversing valve 12 returns to the neutral position under the action of the spring. At this time, ports P and T of the third solenoid reversing valve 12 are connected, the pair of brush hydraulic motors 3 and 4 lose power, and the brush rotation stops.

[0051] like Figure 8 As shown, the coil of the electro-proportional pressure reducing valve 11 is de-energized. The spring forces the valve core of the electro-proportional pressure reducing valve 11 back to the right position, connecting ports A and T on the opposite side of the electro-proportional pressure reducing valve 11. Simultaneously, the right coil of the second solenoid reversing valve 10 is energized. At this point, ports P and A on the opposite side of the second solenoid reversing valve 10 connect to ports ⑧ and ⑨ of the second hydraulically controlled check valve 14. High-pressure hydraulic oil flows through the second solenoid reversing valve 10 and the second hydraulically controlled check valve 14 to the rod chambers of the pair of sweep and brush lift cylinders 7 and 8. The hydraulic oil in the rodless chambers of the pair of sweep and brush lift cylinders 7 and 8 then flows back through the electro-proportional pressure reducing valve 11 to the hydraulic oil tank 1. The rods of the sweep and brush lift cylinders 7 and 8 retract, and the sweep and brush mechanism reaches its highest position. At this point, due to the de-energization of the coil of the second solenoid reversing valve 10, pressure builds up in the rod chambers of the pair of sweep and brush lift cylinders 7 and 8, maintaining a stationary state.

[0052] Similarly, the right coil of the first solenoid valve 9 is energized. Ports P and A on the opposite side of the first solenoid valve 9 communicate with ports ⑤ and ⑥ of the first hydraulically controlled check valve 13. High-pressure oil flows through the first solenoid valve 9 and the first hydraulically controlled check valve 13 to the rod chambers of the pair of brush extension cylinders 5 and 6. The rods of the brush extension cylinders 5 and 6 retract, compressing the springs 21 in the rodless chambers of the brush extension cylinders 5 and 6. The brush mechanism is retracted to the innermost side of the vehicle. At this point, since the coil of the first solenoid valve 9 is de-energized, pressure builds up in the rod chambers of the brush extension cylinders 5 and 6, maintaining a stationary state.

[0053] After the sweeping brush stops rotating and the sweeping brush lifting cylinders 7, 8 and the sweeping brush extension cylinders 5, 6 are retracted into place, the coils of the first seat valve 15 and the second seat valve 16 are de-energized and the hydraulic pump 2 stops rotating, and the entire sweeping brush mechanism is in a non-working state.

[0054] The above description is only a preferred embodiment of the present invention, but the present invention is not limited thereto. All equivalent replacements or equivalent changes of the concepts and technical solutions according to the present invention should be included in the protection scope of the present invention.

Claims

1. A hydraulic control system for a sweeping brush mechanism of a sweeping vehicle, comprising an oil tank, a hydraulic pump, a pair of sweeping brush hydraulic motors, a pair of sweeping brush extension cylinders and a pair of sweeping brush lifting cylinders, wherein the fluid inlet and the fluid outlet of the sweeping brush hydraulic motor are respectively connected to the outlet of the hydraulic pump and the oil tank to form a sweeping brush hydraulic motor control circuit; characterized in that : The sweep brush extension cylinder is connected to the hydraulic pump and the oil tank through the first reversing valve to form a sweep brush extension cylinder control circuit. The rodless chamber of the sweep brush extension cylinder is provided with a spring. The first reversing valve is respectively connected to the rodless chamber and the rod chamber of the sweep brush extension cylinder. The sweep brush lifting cylinder is connected to the hydraulic pump and the oil tank through a second reversing valve to form a sweep brush lifting cylinder control circuit, and the second reversing valve is connected to the rod chamber of the sweep brush lifting cylinder; The sweep brush lifting cylinder control circuit is provided with an electric proportional pressure reducing valve, and the electric proportional pressure reducing valve is connected to the rodless chamber of the sweep brush lifting cylinder; A second hydraulically controlled one-way valve is provided between the second reversing valve and the rod chamber of the sweeping and brushing lifting cylinder; A third seat valve is provided on the sweeping hydraulic motor control circuit, and the third seat valve is connected to the sweeping hydraulic motor and the hydraulic pump respectively. The third seat valve is normally cut off, and becomes connected after the coil is energized; The outlet of the hydraulic pump is connected to a first seat valve, and the outlet of the hydraulic pump is also connected to one port on the same side of the first reversing valve, the second reversing valve, and the electric proportional pressure reducing valve, respectively. The outlet of the first seat valve is connected to the other port on the same side of the first reversing valve, the second reversing valve, and the electric proportional pressure reducing valve, respectively; the other ports on the same side of the first reversing valve, the second reversing valve, and the electric proportional pressure reducing valve are all connected to the oil tank; the first seat valve is normally connected, and becomes cut off after the coil is energized.

2. The hydraulic control system according to claim 1, characterized in that: The sweeping brush extension cylinder is replaced with a hydraulic single-acting cylinder, the rod chamber of the sweeping brush extension cylinder is connected to the first reversing valve and connected to the sweeping brush extension cylinder control circuit, and a spring is installed inside the rodless chamber; the first reversing valve is connected to the rod chamber of the sweeping brush extension cylinder; a first hydraulically controlled one-way valve is added between the pair of sweeping brush extension cylinders and the first reversing valve.

3. The hydraulic control system according to claim 2, characterized in that: A third reversing valve is added to the liquid flow inlet and the liquid flow outlet of the pair of hydraulic motors; one port on the same side of the third reversing valve is connected to the outlet of the third seat valve, and the other port on the same side of the third reversing valve is connected to the oil tank.

4. The hydraulic control system according to claim 3, characterized in that: The third seat valve is cancelled, and a flow regulating distribution valve and a second seat valve are added; the outlet of the hydraulic pump is connected to the inlet of the flow regulating distribution valve; the flow regulating distribution valve has two outlets, one of which is connected to the sweeping brush hydraulic motor, and the other is connected to the sweeping brush extension cylinder and the sweeping brush lifting cylinder respectively; the outlet of the second seat valve is connected to the oil tank; the normal state of the second seat valve is connected, and it becomes cut-off state after the coil is energized.

5. The hydraulic control system according to claim 4, characterized in that: The first reversing valve, the second reversing valve and the third reversing valve are all electromagnetic reversing valves, the first seat valve and the second seat valve are electromagnetic valves, the middle positions of the first reversing valve and the second reversing valve are O type, and the middle position of the third reversing valve is M type.

6. The hydraulic control system according to claim 4, characterized in that: Outlet 1 of the flow regulating distribution valve is connected to the liquid inlet port of the third reversing valve; outlet 2 of the flow regulating distribution valve is respectively connected to a same-side port of the first reversing valve, the second reversing valve, the electric proportional pressure reducing valve and the third reversing valve and is simultaneously connected to the liquid inlet port of the second seat valve.

7. The hydraulic control system according to claim 4, characterized in that: The first seat valve is connected in parallel with a first overflow valve, the second seat valve is connected in parallel with a second overflow valve, and the first reversing valve and the first hydraulically controlled one-way valve are connected in parallel with a third overflow valve.

Images