Dumper hydraulic control system and dumper comprising same

Abstract

The invention provides a dumper hydraulic control system and a dumper comprising the same, and the dumper hydraulic control system comprises an oil source comprising an oil port P and an oil port T; the supporting oil cylinder comprises an oil cavity J and an oil cavity K; the lifting oil cylinder comprises an oil cavity L and an oil cavity M; the support reversing valve is respectively connected with the oil port P, the oil port T, the oil cavity J and the oil cavity K; the lifting reversing valve is respectively connected with the oil port P, the oil port T and the oil cavity M; the pressure control assembly comprises a supporting overflow valve, the oil inlet end and the oil outlet end of the supporting overflow valve are connected with the oil port P and the oil port T respectively, and the overflow amount of the supporting overflow valve is P1; the pressure supplementing assembly comprises a pressure detection device used for detecting the pressure of the oil cavity K, a pressure supplementing oil way connected with the oil cavity K through a pressure supplementing one-way valve, and a pressure supplementing reversing valve connected with the oil cavity L, the lifting reversing valve, the pressure supplementing oil way and the pressure relief oil way. And the length of the supporting mechanism which is driven to extend downwards can be automatically adjusted along with the height change of the frame caused by the change of the load of the material box.

Description

Technical Field

[0001] The invention relates to the field of dump trucks, in particular to a dump truck hydraulic control system and a dump truck containing the same. Background Art

[0002] The purpose of the present invention is to design a hydraulic control system for a dump truck and a dump truck containing the same in view of the problems existing in the above-mentioned prior art. Summary of the invention

[0003] In order to speed up the garbage disposal efficiency, the existing dump trucks are designed to load and unload garbage from the rear and automatically. When unloading, the material box is flipped upward with the rear bottom hinged with the frame as the fulcrum. This makes the material box move with a large amplitude and high height during unloading, resulting in the risk of rollover due to the rearward shift of the center of gravity of the material box during unloading. Therefore, a supporting leg mechanism is also provided at the bottom of the rear end of the frame, which can be extended downward to support the ground and slightly lift the rear part of the frame to stabilize the body before unloading.

[0004] However, the extended length of the existing support legs cannot automatically adjust the frame lifting and lowering caused by the change in the load of the material box. When unloading, the support legs are prone to over-pressing the rear end of the frame, causing the frame to bend and deform significantly under the effect of the backward shift of the center of gravity of the material box load. Or the support legs fail to touch the ground and lose their lifting effect, causing the frame to be compressed and deformed and the vehicle to be at risk of overturning, seriously affecting the safety of the unloading operation and the life of the vehicle body.

[0005] The present invention provides a dump truck hydraulic control system and a dump truck containing the same, which can effectively solve the above problems.

[0006] The present invention is achieved in that:

[0007] A hydraulic control system for a dump truck, the dump truck comprising a vehicle chassis, a frame connected to the upper part of the vehicle chassis through a plurality of leaf springs, a material box arranged on the frame, and a support mechanism arranged at the rear of the frame, the hydraulic control system comprising:

[0008] Oil source, including oil port P and oil port T;

[0009] A supporting oil cylinder, comprising an oil chamber J and an oil chamber K, the supporting oil cylinder being arranged on the frame and used to drive the supporting mechanism to extend and retract upward and downward;

[0010] A lifting cylinder, comprising an oil chamber L and an oil chamber M, wherein the lifting cylinder is arranged on the frame and is used to lift the material box and flip it;

[0011] Support the reversing valve, connected to the oil port P, oil port T, oil chamber J, and oil chamber K respectively;

[0012] A lifting reversing valve is connected to the oil port P, the oil port T, and the oil chamber M respectively;

[0013] A pressure control component, comprising a support relief valve whose oil inlet and oil outlet are respectively connected to the oil port P and the oil port T, and the overflow amount of the support relief valve is P1;

[0014] A pressure compensation component, comprising a pressure detection device for detecting the pressure of the oil chamber K, a pressure compensation oil circuit connected to the oil chamber K through a pressure compensation check valve, and a pressure compensation reversing valve respectively connected to the oil chamber L, the lifting reversing valve, and the pressure compensation oil circuit;

[0015] The control system is used to perform the following steps when the dump truck is unloading:

[0016] S1, control the support reversing valve to conduct the oil port P and oil chamber K, oil port T and oil chamber J so that the support oil cylinder drives the support mechanism to extend downward, when the pressure of the oil port P and oil chamber K reaches P1 to open the support overflow valve to overflow, the support mechanism is set between the frame and the ground and stops extending downward, and the support reversing valve locks the oil chamber K;

[0017] S2, after the support mechanism is installed between the frame and the ground, the lifting reversing valve is controlled to conduct the oil port P and the oil chamber M, the oil port T and the oil chamber L so that the lifting cylinder lifts the material box to turn over and unload;

[0018] S3, during the process of the material box turning over and unloading, when the pressure detection device detects that the pressure of the oil chamber K is less than P3, the pressure compensation reversing valve conducts the oil chamber L and the pressure compensation oil circuit, and the return oil of the oil chamber L is replenished into the oil chamber K in real time so that the support oil cylinder drives the support mechanism to extend downward to the top between the frame and the ground again, and the excess oil in the oil chamber J is returned to the oil port T;

[0019] S4, after the lifting oil cylinder lifts the material box to the right position, the lifting reversing valve is controlled to lock the oil chamber L and the oil chamber M.

[0020] Furthermore, the pressure-compensating assembly further comprises a pressure-relief oil circuit having one end connected to the pressure-compensating oil circuit and the other end connected to the oil inlet end of the support relief valve via a pressure-relief one-way valve;

[0021] The step S3 in which the return oil of the oil chamber L is replenished into the oil chamber K in real time so that the support cylinder drives the support mechanism to extend downward again to be top-mounted between the frame and the ground specifically includes: the return oil of the oil chamber L is replenished into the oil chamber K in real time so that the support cylinder drives the support mechanism to extend downward again until the pressure of the pressure-compensating oil circuit and the oil chamber K reaches P1, and the excess oil overflows through the pressure relief oil circuit and the support overflow valve in sequence so that the support mechanism is top-mounted between the frame and the ground again and stops extending downward.

[0022] Further, the pressure control assembly also includes a pressure control reversing valve connected to the oil port P and the oil inlet end of the supporting relief valve through the oil port A1 and the oil port B1 respectively, the pressure control reversing valve includes a left position for conducting the oil port A1 and the oil port B1, and a right position for locking the oil port B1, and P3<P1 and P1-P3=0.5MPa~2MPa;

[0023] Step S1 specifically includes: the support reversing valve connects the oil port P and the oil chamber K, the oil port T and the oil chamber J so that the support oil cylinder drives the support mechanism to extend downward, and at the same time, the pressure control reversing valve is in the left position. When the pressure of the oil port P and the oil chamber K reaches P1, the support overflow valve opens and connects the oil port T, and the support mechanism is set between the frame and the ground and stops extending downward, the support reversing valve locks the oil chamber K, and the pressure control reversing valve moves to the right position to lock the oil port B1 so that the pressure at the oil inlet end of the support overflow valve remains between P3 and P1.

[0024] Further, the pressure control reversing valve further includes an oil port C1 and an oil port D1, the pressure control assembly further includes a lifting overflow valve whose oil inlet and oil outlet are respectively connected to the oil port D1 and the oil port T, the overflow amount of the lifting overflow valve is P2, the oil port C1 is connected to the oil port T, the right position of the pressure control reversing valve is also used to conduct the oil port A1 and the oil port D1, and lock the oil port C1, and the pressure control reversing valve also includes a middle position for locking the oil port B1 and the oil port D1 and conducting the oil port A1 and the oil port C1;

[0025] Step S4 specifically includes: when the pressure of the oil port P and the oil chamber M reaches P2 so that the lifting overflow valve opens to overflow, the lifting cylinder lifts the material box into place, the lifting reversing valve locks the oil chamber L and the oil chamber M, the lifting cylinder stops lifting, and the pressure control reversing valve moves to the middle position.

[0026] Furthermore, the pressure-compensating reversing valve includes oil ports E, F and G, which are respectively connected to the lifting reversing valve, the oil chamber L and the pressure-compensating oil circuit; the pressure-compensating reversing valve includes a left position for connecting the oil ports E and F and locking the oil port G, and a right position for connecting the oil ports F and G and locking the oil port E.

[0027] Further, the oil chamber J is a small chamber, the oil chamber K is a large chamber, the support reversing valve includes oil port A2, oil port C2, oil port B2, and oil port D2 respectively connected to the oil port P, oil port T, oil chamber K, and oil chamber J, the support reversing valve includes a left station for conducting the oil port A2 and oil port B2, oil port C2 and oil port D2, and a right station for conducting the oil port A2 and oil port D2, oil port C2 and oil port B2, and an intermediate station for locking the oil port A2 and oil port B2, and conducting the oil port C2 and D2, a one-way hydraulic lock is connected between the oil port D2 and the oil chamber J, and the oil inlet end of the one-way hydraulic lock is connected between the oil port B2 and the oil chamber K through a valve opening oil circuit;

[0028] The support reversing valve in step S3 is in the middle position, and the excess oil in the oil chamber J in step S3 is returned to the oil port T specifically including: after the oil pressure in the pressure-compensating oil circuit increases to open the one-way hydraulic lock through the valve-opening oil circuit, the excess oil in the oil chamber J is returned to the oil port T through the oil port D2 and the oil port C2 in turn.

[0029] Further, the oil chamber L is a small chamber, the oil chamber M is a large chamber, the lifting reversing valve includes oil port A3, oil port C3, oil port B3, and oil port D3 respectively connected to the oil port P, oil port T, oil chamber M, and oil port E, the lifting reversing valve includes a left workstation for conducting the oil port A3 and oil port B3, oil port C3 and oil port D3, and a right workstation for conducting the oil port A3 and oil port D3, oil port C3 and oil port B3, and an intermediate workstation for locking the oil port A3, oil port C3, oil port B3, and oil port D3.

[0030] A dump truck comprises the hydraulic control system as described above, as well as a vehicle chassis, a frame, a support mechanism, a material box, and a plurality of leaf springs;

[0031] The frame is located above the vehicle chassis and is connected to the vehicle chassis via a plurality of leaf springs;

[0032] The support mechanism and the support oil cylinder are arranged together at the rear of the frame, and the support oil cylinder is used to drive the support mechanism to extend downward or retract upward;

[0033] The material box is arranged on the frame and the rear part is hinged to the frame. The two ends of the lifting cylinder are respectively hinged to the rear part of the frame and the bottom of the material box and are used to lift the material box and turn it over.

[0034] The beneficial effects of the present invention are:

[0035] 1. By adding a support overflow valve, the overflow volume P1 of the support overflow valve is used to control the length of the support mechanism extending downward to stop when the driving pressure of the driving cylinder reaches P1, so that the length of the support mechanism driven to extend downward can be automatically adjusted with the change of the frame height caused by the change of the load size of the material box. Specifically, the greater the load, the lower the frame height and the support mechanism extends downward for a short length to touch the ground and lift the frame, and the driving pressure of the driving cylinder reaches P1; the smaller the load, the higher the frame height and the support mechanism extends downward for a long length to touch the ground and lift the frame, and the driving pressure of the driving cylinder reaches P1, thereby avoiding the support mechanism from over-lifting the frame after extending downward, resulting in a large-scale frame displacement due to the backward shift of the center of gravity of the material box load. Bending and deformation occur; at the same time, by adding a pressure-compensating component, the return oil of the oil chamber L can be pressurized into the oil chamber K through the pressure-compensating oil circuit, so that the supporting cylinder can drive the supporting mechanism downward to the top between the frame and the ground again, avoiding the load of the material box being reduced as the unloading proceeds, the frame driving the supporting mechanism to move upward, resulting in the bottom of the supporting mechanism not touching the ground and losing the upward function, which in turn causes the frame to be compressed and deformed and the vehicle to be at risk of overturning; therefore, through the arrangement of the pressure control component and the pressure-compensating component, the function of the supporting cylinder driving the supporting mechanism to automatically adjust its extension length with the frame height is added, reducing the frame deformation during unloading to about 20% of the prior art, and improving the unloading operation safety and body life of the dump truck as a whole.

[0036] 2. By adding a pressure relief oil circuit connected between the pressure-compensating oil circuit and the support overflow valve, the overflow volume P1 of the support overflow valve can be used again to further control the return oil of the oil chamber L to replenish the oil chamber K in real time until the pressure reaches P1, and the excess oil will overflow through the pressure relief oil circuit and the support overflow valve to accurately control the real-time oil replenishment volume of the pressure-compensating oil circuit to the oil chamber K, ensuring that the driving mechanism can drive the support mechanism to extend downward again and can be set between the frame and the ground again, and will not be over-promoted to cause the frame to be easily deformed. When unloading, the length of the support mechanism extending downward can be adjusted in real time as the frame height moves upward, so as to ensure the supporting effect of the support mechanism and improve the adaptability of the support mechanism to support the frame.

[0037] 3. By setting the pressure control reversing valve, the oil pressure at the oil inlet end of the support overflow valve is prevented from disappearing, so that the pressure relief oil circuit can generate a back pressure greater than P3 on the compensation oil circuit, to ensure that the return oil of the oil chamber L can be smoothly replenished to the oil chamber K in real time, so that the function of the support cylinder driving the support mechanism to automatically adjust the extension length with the frame height can be stably realized.

[0038] 4. By adding a one-way hydraulic lock and designing the middle position of the support reversing valve, the oil chamber K and the oil chamber L can be stably pressure-maintained through the locking of the oil port B2 and the one-way hydraulic lock. At the same time, after the oil chamber K is replenished to a certain extent through the pressure-replenishing oil circuit in the oil chamber L, the one-way hydraulic lock can be opened through the valve opening oil circuit to return the excess oil in the oil chamber K, further ensuring that the function of the support cylinder driving the support mechanism to automatically adjust the extension length with the frame height can be stably realized. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 This is a schematic diagram of the structure of a dump truck.

[0040] Figure 2 It is a structural schematic diagram of the hydraulic control system of the dump truck in step 1.

[0041] Figure 3 It is a structural diagram of the hydraulic control system of the dump truck in step 3. DETAILED DESCRIPTION

[0042] Reference Figure 1-3 As shown, a hydraulic control system for a dump truck, the dump truck 9 includes a vehicle chassis 91, a frame 92 connected to the vehicle chassis 91 through a plurality of leaf springs 95, a material box 94 provided on the frame 92, and a support mechanism 93 provided at the rear of the frame 92. The hydraulic control system includes:

[0043] Oil source 1, including oil port P and oil port T;

[0044] The supporting oil cylinder 2 includes an oil chamber J and an oil chamber K. The supporting oil cylinder 2 is arranged on the frame 92 and is used to drive the supporting mechanism 93 to extend and retract upward and downward;

[0045] A lifting cylinder 3, including an oil chamber L and an oil chamber M, is provided on the vehicle frame 92 and is used to lift the material box 94 for flipping; specifically, the number of the supporting cylinders 2 is set to two, and the number of the lifting cylinder 3 is set to one;

[0046] Support the reversing valve 4, respectively connected to the oil port P, the oil port T, the oil chamber J, and the oil chamber K;

[0047] The lifting reversing valve 5 is connected to the oil port P, the oil port T, and the oil chamber M respectively;

[0048] The pressure control component 66 includes a support overflow valve 61 whose oil inlet and oil outlet are respectively connected to the oil port P and the oil port T. The overflow amount of the support overflow valve 61 is P1. Specifically, P1 is set to the driving pressure value of the support cylinder 2 when the support mechanism 93 is placed between the frame 92 and the ground and just supports the frame 92 when the material box 94 is empty.

[0049] The pressure compensation component 7 includes a pressure detection device 71 for detecting the pressure of the oil chamber K, a pressure compensation oil circuit 72 connected to the oil chamber K through a pressure compensation check valve 73, and a pressure compensation reversing valve 74 respectively connected to the oil chamber L, the lifting reversing valve 5, and the pressure compensation oil circuit 72. The oil inlet end and the oil outlet end of the pressure compensation check valve 73 are respectively connected to the pressure compensation oil circuit 72 and the oil chamber K. The pressure detection device 71 is a pressure sensor;

[0050] The control system is used to perform the following steps when the dump truck 9 is unloading:

[0051] S1, control the support reversing valve 4 to conduct the oil port P and the oil chamber K, the oil port T and the oil chamber J so that the support oil cylinder 2 drives the support mechanism 93 to extend downward. When the pressure of the oil port P and the oil chamber K reaches P1 to open the support overflow valve 61 to overflow, the support mechanism 93 is placed between the frame 92 and the ground and stops extending downward, and the support reversing valve 4 locks the oil chamber K;

[0052] S2, after the support mechanism 93 is placed between the frame 92 and the ground, the lifting reversing valve 5 is controlled to connect the oil port P and the oil chamber M, the oil port T and the oil chamber L so that the lifting cylinder 3 lifts the material box 94 to turn over and unload;

[0053] S3, in the process of the material box 94 turning over and unloading, as the unloading proceeds, the load of the frame 92 gradually decreases, and the support mechanism 93 is driven to gradually move upward under the elastic force of the leaf spring 95, causing the lower end of the support mechanism 93 to separate from the ground and lose its supporting function. Therefore, when the pressure detection device 71 detects that the pressure of the oil chamber K is less than P3, the pressure compensation reversing valve 74 connects the oil chamber L and the pressure compensation oil circuit 72, and the return oil of the oil chamber L is replenished into the oil chamber K in real time, so that the support oil cylinder 2 drives the support mechanism 93 to extend downward to the top between the frame 92 and the ground again, and the excess oil in the oil chamber J is returned to the oil port T;

[0054] S4, after the lifting oil cylinder 3 lifts the material box 94 to the right position, the lifting reversing valve 5 is controlled to lock the oil chamber L and the oil chamber M.

[0055] The above-mentioned structure is set up, by adding a support overflow valve 61, and utilizing the overflow volume P1 of the support overflow valve 61 to control the length of the support mechanism 93 extending downward to stop when the driving pressure of the driving cylinder reaches P1, so that the length of the support mechanism 93 driven to extend downward can be automatically adjusted with the change in the height of the frame 92 caused by the change in the load size of the material box 94. Specifically, the greater the load, the lower the height of the frame 92 and the support mechanism 93 extends downward for a shorter length before touching the ground and lifting the frame 92, and the driving pressure of the driving cylinder reaches P1; the smaller the load, the higher the height of the frame 92 and the support mechanism 93 extends downward for a longer length before touching the ground and lifting the frame 92, and the driving pressure of the driving cylinder reaches P1, thereby avoiding that the support mechanism 93 pushes up the frame 92 too much after extending downward, resulting in a significant displacement of the frame 92 due to the backward shift of the center of gravity of the load of the material box 94. The situation of bending and deformation of a certain degree occurs; at the same time, by adding the pressure-compensating component 7, the return oil of the oil chamber L can be pressurized into the oil chamber K through the pressure-compensating oil circuit 72, so that the supporting cylinder 2 can drive the supporting mechanism 93 to extend downward to the top between the frame 92 and the ground again, thereby avoiding the load reduction of the material box 94 as the unloading progresses, and the frame 92 driving the supporting mechanism 93 to move upward, resulting in the bottom of the supporting mechanism 93 not touching the ground and losing the upward push function, which in turn causes the frame 92 to be compressed and deformed and the vehicle to have the risk of overturning; therefore, by setting the pressure control component 66 and the pressure-compensating component 7, the function of the supporting cylinder 2 driving the supporting mechanism 93 to extend automatically with the height of the frame 92 is added, and the deformation of the frame 92 during unloading is reduced to about 20% of the prior art, thereby improving the unloading operation safety and vehicle life of the dump truck 9 as a whole.

[0056] In order to accurately control the real-time oil replenishment amount of the pressure-compensating oil circuit 72 to the oil chamber K, the pressure-compensating assembly 7 further includes a pressure-relief oil circuit 75 having one end connected to the pressure-compensating oil circuit 72 and the other end connected to the oil inlet end of the support relief valve 61 through a pressure-relief one-way valve 76, and the oil inlet end and the oil outlet end of the pressure-relief one-way valve 76 are respectively connected to the pressure-relief oil circuit 75 and the oil inlet end of the support relief valve 61;

[0057] The step S3 in which the return oil of the oil chamber L is replenished into the oil chamber K in real time so that the support cylinder 2 can drive the support mechanism 93 to extend downward again to be top-mounted between the frame 92 and the ground specifically includes: the return oil of the oil chamber L is replenished into the oil chamber K in real time so that the support cylinder 2 can drive the support mechanism 93 to extend downward again until the pressure of the pressure-compensating oil circuit 72 and the oil chamber K reaches P1, and the excess oil overflows through the pressure relief oil circuit 75 and the support overflow valve 61 in turn, so that the support mechanism 93 is top-mounted between the frame 92 and the ground again and stops extending downward. Therefore, by adding the pressure relief oil circuit 75 connected between the pressure replenishing oil circuit 72 and the support overflow valve 61, the overflow volume P1 of the support overflow valve 61 can be used again to further control the return oil of the oil chamber L to replenish the oil chamber K in real time until the pressure reaches P1, and the excess oil will overflow through the pressure relief oil circuit 75 and the support overflow valve 61 to accurately control the real-time oil replenishment amount of the oil chamber K by the pressure replenishing oil circuit 72, to ensure that the driving mechanism drives the support mechanism 93 to extend downward again and can be set between the frame 92 and the ground again, and will not over-upward to cause the frame 92 to be easily deformed. When unloading, the length of the support mechanism 93 extending downward can be adjusted in real time with the increase in the height of the frame 92 to ensure the supporting effect of the support mechanism 93 and improve the adaptability of the support mechanism 93 to support the frame 92.

[0058] In order to ensure that the return oil of the oil chamber L can be smoothly replenished into the oil chamber K, the pressure control component 66 also includes a pressure control reversing valve 62 connected to the oil port P and the oil inlet end of the support relief valve 61 through the oil port A1 and the oil port B1 respectively, and the pressure control reversing valve 62 includes a left position for conducting the oil port A1 and the oil port B1, and a right position for locking the oil port B1, and P3<P1 and P1-P3=0.5MPa~2Mpa, preferably, P1-P3=1Mpa;

[0059] Step S1 specifically includes: the support reversing valve 4 connects the oil port P and the oil chamber K, the oil port T and the oil chamber J so that the support oil cylinder 2 drives the support mechanism 93 to extend downward, and at the same time, the pressure control reversing valve 62 is in the left position. When the pressure of the oil port P and the oil chamber K reaches P1, the support overflow valve 61 opens and connects the oil port T, and the support mechanism 93 is set between the frame 92 and the ground and stops extending downward, the support reversing valve 4 locks the oil chamber K, and the pressure control reversing valve 62 moves to the right position to lock the oil port B1 so that the pressure at the oil inlet end of the support overflow valve 61 remains between P3 and P1. Therefore, by setting the pressure control reversing valve 62, the oil pressure at the oil inlet end of the support overflow valve 61 is prevented from disappearing, so that the pressure relief oil circuit 75 can generate a back pressure greater than P3 on the compensation oil circuit, so as to ensure that the return oil of the oil chamber L can be smoothly and real-timely replenished to the oil chamber K, so that the function of the support cylinder 2 driving the support mechanism 93 to extend and automatically adjust the height of the frame 92 can be stably realized.

[0060] In order to accurately control the lifting stroke of the lifting cylinder 3, the pressure control reversing valve 62 also includes an oil port C1 and an oil port D1, and the pressure control component 66 also includes a lifting overflow valve 6363 whose oil inlet and oil outlet are respectively connected to the oil port D1 and the oil port T, and the overflow amount of the lifting overflow valve 6363 is P2, and the P2 is set to the driving pressure value of the lifting cylinder 3 after the material box 94 is flipped into place, the oil port C1 is connected to the oil port T, and the right position of the pressure control reversing valve 62 is also used to conduct the oil port A1 and the oil port D1 and lock the oil port C1. The pressure control reversing valve 62 also includes an intermediate position for locking the oil port B1 and the oil port D1 and conducting the oil port A1 and the oil port C1;

[0061] Step S4 specifically includes: when the pressure of the oil port P and the oil chamber M reaches P2, the lifting relief valve 6363 opens and overflows, the lifting oil cylinder 3 lifts the material box 94 to the position, the lifting reversing valve 5 locks the oil chamber L and the oil chamber M, the lifting oil cylinder 3 stops lifting, and the pressure control reversing valve 62 moves to the middle position. Thus, through the setting of the lifting relief valve 6363, after the driving pressure value of the lifting oil cylinder 3 reaches P2, the oil inlet of the oil port P overflows through the lifting relief valve 6363 and then returns to the oil port T, thereby ensuring that the lifting oil cylinder 3 stops after lifting the material box 94 to the position, and there is no need to use an external position sensor or other device to detect the flipping position of the material box 94, which saves costs and improves the accuracy and safety of the lifting positioning of the lifting mechanism compared to sensor positioning, and there will be no detection failure, which will cause the control system to make an erroneous judgment and issue an erroneous command.

[0062] Specifically, the pressure-compensating reversing valve 74 includes oil ports E, F and G, which are respectively connected to the lifting reversing valve 5, the oil chamber L and the pressure-compensating oil circuit 72. The pressure-compensating reversing valve 74 includes a left position for connecting the oil ports E and F and locking the oil port G, and a right position for connecting the oil ports F and G and locking the oil port E.

[0063] In this embodiment, the oil chamber J is a small chamber, and the oil chamber K is a large chamber. In other embodiments, the oil chamber J and the oil chamber K may also be large chambers. The support reversing valve 4 includes an oil port A2, an oil port C2, an oil port B2, and an oil port D2 respectively connected to the oil port P, the oil port T, the oil chamber K, and the oil chamber J. The support reversing valve 4 includes a left station for conducting the oil port A2 and the oil port B2, the oil port C2 and the oil port D2, and a right station for conducting the oil port A2 and the oil port D2, the oil port C2 and the oil port B2, and an intermediate station for locking the oil port A2 and the oil port B2, and conducting the oil ports C2 and D2. A one-way hydraulic lock 8 is connected between the oil port D2 and the oil chamber J, and the oil inlet end of the one-way hydraulic lock 8 is connected between the oil port B2 and the oil chamber K through a valve opening oil circuit 81;

[0064] In step S3, the support reversing valve 4 is in the middle position, and the excess oil in the oil chamber J is returned to the oil port T in step S3 specifically includes: after the oil pressure in the pressure-compensating oil circuit 72 increases to open the one-way hydraulic lock 8 through the valve opening oil circuit 81, the excess oil in the oil chamber J is returned to the oil port T through the oil port D2 and the oil port C2 in sequence. Thus, by adding the one-way hydraulic lock 8 and designing the middle position of the support reversing valve 4, the oil chamber K and the oil chamber L can be stably pressure-maintained by locking the oil port B2 and the one-way hydraulic lock 8. At the same time, after the oil chamber K is replenished to a certain extent in the oil chamber L through the pressure-compensating oil circuit 72, the one-way hydraulic lock 8 can be opened through the valve opening oil circuit 81 to return the excess oil in the oil chamber K, further ensuring that the function of the support oil cylinder 2 driving the support mechanism 93 to automatically adjust the extension length with the height of the frame 92 can be stably realized.

[0065] In this embodiment, the oil chamber L is a small chamber, and the oil chamber M is a large chamber. In other embodiments, the oil chamber L and the oil chamber M may also be large chambers, the oil chamber L is a small chamber, and the oil chamber M is a large chamber. The lifting reversing valve 5 includes oil port A3, oil port C3, oil port B3, and oil port D3 respectively connected to the oil port P, oil port T, oil chamber M, and oil port E. The lifting reversing valve 5 includes a left station for conducting the oil port A3 and the oil port B3, the oil port C3 and the oil port D3, and a right station for conducting the oil port A3 and the oil port D3, the oil port C3 and the oil port B3, and an intermediate station for locking the oil port A3, the oil port C3, the oil port B3, and the oil port D3.

[0066] In another embodiment, a dump truck 9 is also included, including the hydraulic control system as described above, as well as a vehicle chassis 91, a frame 92, a support mechanism 93, a material box 94, and a plurality of leaf springs 95;

[0067] The vehicle frame 92 is located above the vehicle chassis 91 and is connected to the vehicle chassis 91 through a plurality of leaf springs 95;

[0068] The support mechanism 93 and the support cylinder 2 are arranged together at the rear of the frame 92, and the support cylinder 2 is used to drive the support mechanism 93 to extend downward or retract upward;

[0069] The material box 94 is arranged on the frame 92 and the rear part is hinged to the frame 92. The two ends of the lifting cylinder 3 are respectively hinged to the rear part of the frame 92 and the bottom of the material box 94 and are used to lift the material box 94 to flip it.

[0070] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A hydraulic control system for a dump truck, the dump truck (9) comprising a vehicle chassis (91), a frame (92) connected to the upper part of the vehicle chassis (91) via a plurality of leaf springs (95), a material box (94) arranged on the frame (92), and a support mechanism (93) arranged at the rear of the frame (92), characterized in that: The hydraulic control system comprises: An oil source (1), including an oil port P and an oil port T; A supporting oil cylinder (2), comprising an oil chamber J and an oil chamber K, wherein the supporting oil cylinder (2) is arranged on the vehicle frame (92) and is used to drive the supporting mechanism (93) to extend and retract upward and downward; A lifting cylinder (3), comprising an oil chamber L and an oil chamber M, wherein the lifting cylinder (3) is arranged on the vehicle frame (92) and is used to lift the material box (94) and flip it; A supporting reversing valve (4) is connected to the oil port P, the oil port T, the oil chamber J, and the oil chamber K respectively; A lifting reversing valve (5) is connected to the oil port P, the oil port T, and the oil chamber M respectively; A pressure control component (6), comprising a support overflow valve (61) whose oil inlet and oil outlet are respectively connected to the oil port P and the oil port T, and the overflow amount of the support overflow valve (61) is P1; A pressure compensation component (7), comprising a pressure detection device (71) for detecting the pressure of the oil chamber K, a pressure compensation oil circuit (72) connected to the oil chamber K via a pressure compensation check valve (73), and a pressure compensation reversing valve (74) respectively connected to the oil chamber L, the lifting reversing valve (5), and the pressure compensation oil circuit (72); A control system is used to perform the following steps when the dump truck (9) is unloading: S1, controlling the support reversing valve (4) to conduct the oil port P and the oil chamber K, the oil port T and the oil chamber J so that the support oil cylinder (2) drives the support mechanism (93) to extend downward, and when the pressure of the oil port P and the oil chamber K reaches P1 so that the support overflow valve (61) opens to overflow, the support mechanism (93) is placed between the vehicle frame (92) and the ground and stops extending downward, and the support reversing valve (4) locks the oil chamber K; S2, after the support mechanism (93) is placed between the vehicle frame (92) and the ground, the lifting reversing valve (5) is controlled to conduct the oil port P and the oil chamber M, the oil port T and the oil chamber L so that the lifting cylinder (3) lifts the material box (94) to turn over and unload the material; S3, during the process of the material box (94) turning over and unloading, when the pressure detection device (71) detects that the pressure of the oil chamber K is less than P3, the pressure compensation reversing valve (74) conducts the oil chamber L and the pressure compensation oil circuit (72), and the return oil of the oil chamber L is replenished into the oil chamber K in real time so that the support cylinder (2) drives the support mechanism (93) to extend downward to the top between the frame (92) and the ground again, and the excess oil in the oil chamber J is returned to the oil port T; S4, after the lifting oil cylinder (3) lifts the material box (94) to the right position, the lifting reversing valve (5) is controlled to lock the oil chamber L and the oil chamber M.

2. A dump truck hydraulic control system as claimed in claim 1, characterized in that: The pressure-compensating assembly (7) further comprises a pressure-relief oil circuit (75) having one end connected to the pressure-compensating oil circuit (72) and the other end connected to the oil inlet end of the support relief valve (61) via a pressure-relief one-way valve (76); The step S3 in which the return oil of the oil chamber L is replenished into the oil chamber K in real time so that the support cylinder (2) drives the support mechanism (93) to extend downward to the top between the frame (92) and the ground comprises: the return oil of the oil chamber L is replenished into the oil chamber K in real time so that the support cylinder (2) drives the support mechanism (93) to extend downward again until the pressure of the pressure-compensating oil circuit (72) and the oil chamber K reaches P1, and the excess oil overflows through the pressure relief oil circuit (75) and the support overflow valve (61) in turn so that the support mechanism (93) is again topped between the frame (92) and the ground and stops extending downward.

3. A dump truck hydraulic control system as claimed in claim 1, characterized in that: The pressure control assembly (6) further comprises a pressure control reversing valve (62) connected to the oil port P and the oil inlet end of the support relief valve (61) through the oil port A1 and the oil port B1 respectively, the pressure control reversing valve (62) comprising a left position for conducting the oil port A1 and the oil port B1, and a right position for locking the oil port B1, wherein P3<P1 and P1-P3=0.5MPa-2MPa; Step S1 specifically includes: the support reversing valve (4) conducts the oil port P and the oil chamber K, the oil port T and the oil chamber J so that the support oil cylinder (2) drives the support mechanism (93) to extend downward, and at the same time, the pressure control reversing valve (62) is in the left position. When the pressure of the oil port P and the oil chamber K reaches P1, the support overflow valve (61) opens and conducts the oil port T, and the support mechanism (93) is placed between the frame (92) and the ground and stops extending downward, the support reversing valve (4) locks the oil chamber K, and the pressure control reversing valve (62) moves to the right position to lock the oil port B1 so that the pressure at the oil inlet end of the support overflow valve (61) remains between P3 and P1.

4. A dump truck hydraulic control system as claimed in claim 3, characterized in that: The pressure control reversing valve (62) further comprises an oil port C1 and an oil port D1, the pressure control assembly (6) further comprises a lifting overflow valve (63) whose oil inlet and oil outlet are respectively connected to the oil port D1 and the oil port T, the overflow amount of the lifting overflow valve (63) is P2, the oil port C1 is connected to the oil port T, the right position of the pressure control reversing valve (62) is also used to conduct the oil port A1 and the oil port D1 and lock the oil port C1, and the pressure control reversing valve (62) further comprises an intermediate position for locking the oil port B1 and the oil port D1 and conducting the oil port A1 and the oil port C1; Step S4 specifically includes: when the pressure of the oil port P and the oil chamber M reaches P2 so that the lifting overflow valve (63) opens to overflow, the lifting cylinder (3) lifts the material box (94) into place, the lifting reversing valve (5) locks the oil chamber L and the oil chamber M, the lifting cylinder (3) stops lifting, and the pressure control reversing valve (62) moves to the middle position.

5. A dump truck hydraulic control system as claimed in claim 1, characterized in that: The pressure-compensating reversing valve (74) includes an oil port E, an oil port F, and an oil port G respectively connected to the lifting reversing valve (5), the oil chamber L, and the pressure-compensating oil circuit (72); the pressure-compensating reversing valve (74) includes a left position for conducting the oil port E and the oil port F and locking the oil port G, and a right position for conducting the oil port F and the oil port G and locking the oil port E.

6. A dump truck hydraulic control system as claimed in claim 1, characterized in that: The oil chamber J is a small chamber, and the oil chamber K is a large chamber. The support reversing valve (4) includes an oil port A2, an oil port C2, an oil port B2, and an oil port D2 respectively connected to the oil port P, the oil port T, the oil chamber K, and the oil chamber J. The support reversing valve (4) includes a left position for conducting the oil port A2 and the oil port B2, the oil port C2 and the oil port D2, and a right position for conducting the oil port A2 and the oil port D2, the oil port C2 and the oil port B2, and an intermediate position for locking the oil port A2 and the oil port B2, and conducting the oil port C2 and the oil port D2. A one-way hydraulic lock (8) is connected between the oil port D2 and the oil chamber J, and the oil inlet end of the one-way hydraulic lock (8) is connected between the oil port B2 and the oil chamber K through a valve opening oil circuit (81); In step S3, the support reversing valve (4) is in the middle position, and the excess oil in the oil chamber J in step S3 is returned to the oil port T specifically including: after the oil pressure in the pressure-compensating oil circuit (72) increases to open the one-way hydraulic lock (8) through the valve opening oil circuit (81), the excess oil in the oil chamber J is returned to the oil port T through the oil port D2 and the oil port C2 in sequence.

7. A dump truck hydraulic control system as claimed in claim 5, characterized in that: The oil chamber L is a small chamber, the oil chamber M is a large chamber, the lifting reversing valve (5) comprises an oil port A3, an oil port C3, an oil port B3, and an oil port D3 respectively connected to the oil port P, the oil port T, the oil chamber M, and the oil port E, the lifting reversing valve (5) comprises a left position for conducting the oil port A3 and the oil port B3, the oil port C3 and the oil port D3, a right position for conducting the oil port A3 and the oil port D3, the oil port C3 and the oil port B3, and an intermediate position for locking the oil port A3, the oil port C3, the oil port B3, and the oil port D3.

8. A dump truck, characterized in that: It comprises a hydraulic control system as claimed in any one of claims 1 to 7, as well as a vehicle chassis (91), a frame (92), a support mechanism (93), a material box (94), and a plurality of leaf springs (95); The vehicle frame (92) is located above the vehicle chassis (91) and is connected to the vehicle chassis (91) via a plurality of leaf springs (95); The support mechanism (93) and the support oil cylinder (2) are arranged together at the rear part of the frame (92), and the support oil cylinder (2) is used to drive the support mechanism (93) to extend downward or retract upward; The material box (94) is arranged on the frame (92) and the rear part is hinged to the frame (92); the two ends of the lifting cylinder (3) are respectively hinged to the rear part of the frame (92) and the bottom of the material box (94) and are used to lift the material box (94) and turn it over.

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