Intelligent control system of hydraulic suspension device

Abstract

The present invention discloses an intelligent control system for a hydraulic suspension device, comprising: two adjacent valve stem sections of a valve stem of a hydraulic distributor are respectively provided with a rising speed control cone surface and a falling speed control cone surface; when the hydraulic distributor is in an ascending or descending working position, the valve stem forms an ascending speed throttling gap or a falling speed throttling gap with the valve body at the ascending speed control cone surface or the falling speed control cone surface, and the throttling area of ​​the ascending speed throttling gap or the falling speed control cone surface can be changed by controlling the axial displacement of the valve stem by an electronic control unit, thereby controlling the ascending speed throttling gap or the falling speed control cone surface, and thus controlling the ascending or descending speed of the agricultural implement. Since the first working oil circuit is provided with a stop valve, in a neutral state, the stop valve is closed under the action of a return spring, cutting off the connection between the rodless chamber of the lifting oil cylinder and the hydraulic distributor, avoiding the settlement of the agricultural implement caused by leakage of the hydraulic distributor, and meeting the static settlement requirements of the agricultural implement.

Description

Technical Field

[0001] The invention relates to a hydraulic suspension device for agricultural equipment, and in particular to an intelligent control system for the hydraulic suspension device. Background Art

[0002] The hydraulic suspension device of agricultural equipment (such as tractors) is used to hang suspended or semi-suspended agricultural implements, lift and lower agricultural implements, adjust tillage depth, realize loading and hydraulic power output, etc. The hydraulic suspension device consists of a hydraulic system and a suspension mechanism. The hydraulic system includes an oil pump, a distributor, a lifting cylinder, an oil cylinder operating mechanism, etc. The suspension mechanism includes an upper pull rod, a lower pull rod, a lifting arm, etc. On the one hand, by manipulating the distributor, the agricultural implement can be raised, lowered, neutralized, and floated, so that the tractor has position control, force control, and force-position integrated control functions. On the other hand, in the field transfer operation, the hydraulic suspension device can realize active shock absorption of the agricultural implement.

[0003] In view of the first aspect, Chinese utility model patent CN202385466U discloses an electric-controlled distributor, which uses a lead screw nut mechanism driven by an electromagnet or a motor as a linear actuator, and controls the valve stem of the distributor to move to the set positions such as rising, falling, neutral, and floating through sensors and electronic control units, thereby realizing intelligent control of the hydraulic lifter. However, driving the valve stem of large and medium-sized hydraulic distributors to move requires a lot of energy, and the linear actuator in the above patent technology consumes a lot of electrical power, and the cost and service life are also subject to certain restrictions.

[0004] To this end, Chinese invention patent CN103047210A discloses an electro-hydraulic operating device for a hydraulic distributor, which controls the movement of the distributor and uses the power of the host hydraulic system as the energy for the valve stem movement operation, saving the consumption of electrical power. However, the device still has the following technical defects:

[0005] 1) When the agricultural equipment is in the tillage state, frequent use of the pressure of the main oil circuit will cause system energy waste;

[0006] 2) Four solenoid valves are used to control the movement of the valve core, and the structure is complex.

[0007] In order to reduce the consumption of system energy and solve the problem of excessive use of main oil circuit pressure when the agricultural implement is in operation, Chinese utility model patent application CN202020989612.9 discloses an intelligent control system for a hydraulic suspension device, including: a lifting cylinder and a hydraulic distributor, the hydraulic distributor including four working positions corresponding to the rising working mode, the descending working mode, the neutral working mode and the floating working mode of the agricultural implement, respectively, the first working oil port of the hydraulic distributor is connected to the rodless chamber of the lifting cylinder through the first working oil circuit, the second working oil port of the hydraulic distributor is connected to the rod chamber of the lifting cylinder through the second working oil circuit, the pressure oil port of the hydraulic distributor is connected to the main oil circuit, and the main oil circuit is provided with a switch valve; a force sensor, the force sensor is used to detect the load on the lower pull rod or the upper pull rod the tension information received; a lifter position sensor, the lifter position sensor is used to detect the position information of the lifter; a valve stem displacement sensor is used to detect the displacement information of the valve stem of the hydraulic distributor; the force sensor, the lifter position sensor and the valve stem displacement sensor are electrically connected to the electronic control unit respectively; an energy storage oil circuit, the energy storage oil circuit includes an accumulator, the accumulator is connected to the main oil circuit through a second one-way valve; the accumulator is connected to the first working oil circuit and the second working oil circuit respectively through a pressure reversing valve; one end of the valve stem of the hydraulic distributor is connected to a hydraulic push rod, and the other end is provided with a return spring; the hydraulic push rod is connected to the energy storage oil circuit through an oil filling solenoid valve, the hydraulic push rod returns oil and releases pressure through an oil discharge solenoid valve, and the oil filling solenoid valve and the oil discharge solenoid valve are electrically connected to the electronic control unit respectively.

[0008] When the implement is in the ascending working mode or the neutral working mode, the hydraulic oil in the first working oil circuit is in a high-pressure state, and the second working oil circuit returns oil to release pressure. Under the action of the high-pressure oil, the high-pressure oil in the first working oil circuit charges the accumulator; when the implement is in the descending working mode, the hydraulic oil in the second working oil circuit is in a high-pressure state, and the first working oil circuit returns oil to release pressure, and the high-pressure oil in the second working oil circuit charges the accumulator; only when the implement is in the floating working mode, because the hydraulic oils in the first and second working oil circuits are unloaded at this time, the accumulator cannot be charged, the switch valve is closed, and the main oil circuit charges the accumulator. Therefore, when the implement is in operation, the main oil circuit pressure is used less, reducing the consumption of system energy.

[0009] Moreover, only when the oil filling solenoid valve is powered on and opened, the high-pressure oil in the accumulator pushes the hydraulic push rod, and the hydraulic distributor valve stem moves to the left. Only when the oil discharge solenoid valve is powered on and opened, the hydraulic oil of the hydraulic push rod is depressurized, and the hydraulic distributor valve stem moves to the right under the action of the return spring. The electronic control unit detects the force information of the lower pull rod or the upper pull rod through the force sensor, detects the position information of the lifter through the lifter position sensor, controls the movement of the hydraulic distributor valve stem by controlling the switch of the oil filling solenoid valve and the oil discharge solenoid valve, and feeds back the valve stem position information through the valve stem displacement sensor to realize the rising, falling, neutral and floating functions of the agricultural implement. Compared with the solution of controlling the valve stem with four solenoid valves, only two solenoid valves and one return spring are needed to control the movement of the hydraulic distributor valve stem, and the structure is simpler and more reliable.

[0010] However, during use, it was found that the hydraulic system could not adjust the rising and falling speeds of the agricultural implements, which restricted the performance of the tractor's electronic control system.

[0011] Another function of the hydraulic suspension device is to actively reduce the vibration of the agricultural implement.

[0012] The basic principle of active shock absorption is to use the up and down movement of the lifting cylinder to compensate for the up and down vibration of the attached agricultural implement. When the tractor starts to vibrate due to the road surface, the electronic control unit collects information from the force sensor and position sensor, determines the vibration amplitude and direction of the agricultural implement, and fills or drains the rod chamber and rodless chamber of the lifting cylinder through the electronically controlled hydraulic valve, so that the lifting cylinder produces a displacement opposite to the vibration direction, thereby reducing the vibration of the attached agricultural implement. This places high demands on the responsiveness of the electronic control unit and the electronically controlled hydraulic valve. In application, the lifting cylinder has a lag problem, which seriously affects the shock absorption effect.

[0013] In order to reduce the responsiveness requirements for the electronic control unit and the electronically controlled hydraulic valve and improve the active shock absorption effect of the attached agricultural implements, Chinese invention patent CN111520367A discloses an electronically controlled hydraulic system of a hydraulic suspension device, a tractor and an active shock absorption control method, wherein a first overflow pressure-maintaining branch oil circuit for overflowing and maintaining pressure in the rodless chamber of the lifting cylinder and a second overflow pressure-maintaining branch oil circuit for overflowing and maintaining pressure in the rod chamber of the lifting cylinder are arranged between the first working oil circuit and the second working oil circuit, and the first overflow pressure-maintaining branch oil circuit and the second overflow pressure-maintaining branch oil circuit are provided with electronically controlled switch valves.

[0014] When a towing farm implement (tractor) with farm implements suspended thereon begins to move to another field, the vibration generated by the bumpy road surface will cause the cylinder body and the piston rod of the lifting cylinder to instantly move relative to each other, thereby generating high-pressure oil in the rodless chamber or the rod chamber. Since a first overflow pressure-maintaining branch oil passage and a second overflow pressure-maintaining branch oil passage are provided between the first working oil passage and the second working oil passage, the high-pressure oil can automatically flow to the other chamber of the lifting cylinder through the first overflow pressure-maintaining branch oil passage or the second overflow pressure-maintaining branch oil passage, so that the vibration amplitude of the attached farm implement is smaller than the vibration amplitude of the towing farm implement, thereby achieving Active shock absorption; in the above-mentioned automatic oil filling step, the participation of the electronically controlled hydraulic valve is not required, so there is no response lag phenomenon; before the above-mentioned automatic oil filling step is completed, the electronically controlled hydraulic valve can be opened in advance, and at the end of the automatic oil filling step, the electronically controlled hydraulic valve can immediately start to replenish hydraulic oil from the main oil circuit to the cavity from which the high-pressure oil flows out. Since the above-mentioned electronically controlled oil filling step can be intervened in advance, the adverse effects caused by the response lag of the system are compensated, so the responsiveness requirements of the electronic control unit and the electronically controlled hydraulic valve are greatly reduced, thereby improving the active shock absorption effect of the attached agricultural implements.

[0015] During the transfer operation, due to the different effective cross-sectional areas of the rod chamber and the rodless chamber of the lifting cylinder, when the cylinder body of the lifting cylinder instantly moves upward relative to the piston rod, the volume of the hydraulic oil flowing out of the rodless chamber is greater than the volume of the hydraulic oil required for the rod chamber, affecting the shock absorbing effect; similarly, when the cylinder body of the lifting cylinder instantly moves downward relative to the piston rod of the lifting cylinder, the volume of the hydraulic oil flowing out of the rod chamber is less than the volume of the hydraulic oil required for the rodless chamber, and a vacuum will be formed in the rodless chamber, causing cavitation.

[0016] In addition, when the hydraulic distributor is in the neutral working mode, the force of the agricultural implement acting on the lifting cylinder forms high pressure on the hydraulic oil, which is transmitted to the hydraulic distributor and leaks through the gap between the valve body and the valve stem in the hydraulic distributor, causing the agricultural implement to sink. Summary of the invention

[0017] In view of the above-mentioned deficiencies in the prior art, the present invention provides an intelligent control system for a hydraulic suspension device, which not only reduces the driving force required for the axial movement of the valve stem of the hydraulic distributor and increases the response speed, but also enables adjustable rising and lowering speeds of agricultural implements.

[0018] In order to solve the above technical problems, the technical solution adopted by the present invention is:

[0019] 14. The hydraulic suspension device of claim 13, wherein the hydraulic distributor comprises a valve body and a valve stem arranged in the valve body, the valve body being provided with a first working oil chamber communicating with a first working oil port, a second working oil chamber communicating with a second working oil port, a pressure oil chamber communicating with a pressure oil port, and a return oil chamber communicating with an oil return port, the first working oil port being communicated with a rodless chamber of the lifting cylinder through a first working oil circuit, the second working oil port being communicated with a rod chamber of the lifting cylinder through a second working oil circuit, the pressure oil port being communicated with a main oil circuit, and the return oil port being communicated with an oil tank; the hydraulic distributor being provided with a neutral working position, a rising working position, a falling working position, and a floating working position position; the valve stem is provided with a plurality of valve stem sections for controlling the connection or disconnection of the corresponding oil chambers, one end of the valve stem is connected to a hydraulic push rod, and the other end is provided with a return spring; an energy storage oil circuit, the energy storage oil circuit includes an accumulator, the accumulator is connected to the first working oil circuit through a first one-way valve, the accumulator is connected to the second working oil circuit through a second one-way valve, and the accumulator is connected to the main oil circuit through a third one-way valve; the hydraulic push rod is connected to the energy storage oil circuit through an oil charging solenoid valve, the hydraulic push rod returns oil and releases pressure through an oil discharge solenoid valve, and the oil charging solenoid valve and the oil discharge solenoid valve are electrically connected to the electronic control unit respectively; a force sensor, the force sensor is used to detect the position of the lower pull rod or the upper pull rod The pull force information borne; the lifter position sensor, the lifter position sensor is used to detect the position information of the lifter; the valve stem displacement sensor is used to detect the displacement information of the valve stem of the hydraulic distributor; the force sensor, the lifter position sensor and the valve stem displacement sensor are electrically connected to the electronic control unit respectively; the two adjacent valve stem sections of the valve stem are respectively provided with a rising speed control cone surface and a falling speed control cone surface; when the hydraulic distributor is in the neutral working position, the pressure oil chamber is connected to the return oil chamber, the first working oil chamber is closed, and the second working oil chamber is closed; when the hydraulic distributor is in the rising working position, the pressure oil chamber is disconnected from the return oil chamber, and the valve stem is in the upper A rising speed throttling gap is formed between the valve body and the rising speed control cone surface, the first working oil chamber is connected to the pressure oil chamber through the rising speed throttling gap, and the second working oil chamber is connected to the return oil chamber; when the hydraulic distributor is in the descending working position, the pressure oil chamber is disconnected from the return oil chamber, and the valve stem forms a descending speed throttling gap with the valve body at the descending speed control cone surface, the first working oil chamber is connected to the return oil chamber through the descending speed throttling gap, and the second working oil chamber is connected to the pressure oil chamber; when the hydraulic distributor is in the floating working position, the pressure oil chamber, the first working oil chamber and the second working oil chamber are respectively connected to the return oil chamber.

[0020] Wherein, the hydraulic distributor is provided with a neutral pressurizing working position. When the hydraulic distributor is in the neutral pressurizing working position, the pressure oil chamber is disconnected from the return oil chamber, the first working oil chamber is closed, and the second working oil chamber is closed.

[0021] Wherein, the hydraulic distributor is provided with a floating pressurizing working position. When the hydraulic distributor is in the floating pressurizing working position, the pressure oil chamber is disconnected from the return oil chamber, the first working oil chamber is connected to the return oil chamber, and the second working oil chamber is connected to the return oil chamber.

[0022] Among them, a first overflow pressure-maintaining branch oil circuit for overflowing and maintaining pressure in the rodless chamber of the lifting cylinder and a second overflow pressure-maintaining branch oil circuit for overflowing and maintaining pressure in the rod chamber of the lifting cylinder are arranged between the first working oil circuit and the second working oil circuit; the first overflow pressure-maintaining branch oil circuit includes a first overflow pressure-maintaining valve, and the opening pressure of the first overflow pressure-maintaining valve is not less than the pressure of the agricultural implement on the first working oil port when the electronically controlled hydraulic valve is in a neutral state; the second overflow pressure-maintaining branch oil circuit includes a second overflow pressure-maintaining valve.

[0023] Among them, a valve stem section of the valve stem is provided with a throttling step surface; the hydraulic distributor is provided with a shock-absorbing working position. When the hydraulic distributor is in the shock-absorbing working position, the throttling step surface and the corresponding inner hole of the valve body form a throttling gap that connects the second working oil chamber with the return oil chamber, the pressure oil chamber is connected with the return oil chamber, and the first working oil chamber is closed.

[0024] Wherein, the first working oil circuit is provided with a stop valve, the stop valve includes a valve sleeve, a valve core, a return spring and a pressure cover device, the valve sleeve includes a first valve sleeve and a second valve sleeve axially arranged and fixedly connected together, the return spring is located in the second valve sleeve and clamped between the pressure cover device and the valve core; the first valve sleeve is provided with a first cavity and a first oil port connected to the first cavity, the second valve sleeve is provided with a second cavity and a second oil port connected to the second cavity; the first oil port is connected to the first working oil port of the hydraulic distributor, and the second oil port is connected to the rodless cavity of the lifting cylinder; of course, it is also possible to set the first oil port to be connected to the rodless cavity of the lifting cylinder, and the second oil port to be connected to the second working oil port of the hydraulic distributor; the valve core includes a first valve core section and a second valve core section with the same outer diameter, and the first valve core section and the second valve core section are connected. An annular groove is provided, and the annular groove corresponds to the position of the first cavity. The first valve core section is slidably matched with the first valve sleeve, and the second valve core section is slidably matched with the second valve sleeve. The second valve core section is provided with a flange near the annular groove, and the flange is provided with a valve core sealing cone surface. The end of the first valve sleeve is provided with a valve sleeve sealing cone surface. The taper of the valve core sealing cone surface and the valve sleeve sealing cone surface are different. Under the action of the return spring, the valve core sealing cone surface abuts against the inner edge of the valve sleeve sealing cone surface to disconnect the first cavity from the second cavity; the valve core is connected to a linear actuator through a connecting device, and the linear actuator is electrically connected to the electronic control unit. When the linear actuator is energized, it drives the valve core to move, so that the valve core sealing cone surface is separated from the valve sleeve sealing cone surface, thereby connecting the first cavity with the second cavity.

[0025] Alternatively, the free end of the first valve sleeve is exposed as a hydraulic control port, the hydraulic control port is connected to the main oil circuit, and the preset elastic force of the return spring is greater than the thrust of the oil pressure on the valve core when the main oil circuit is in a pressure relief state but less than the thrust of the oil pressure on the valve core when the main oil circuit is in a high-pressure state.

[0026] Among them, the connecting device includes a pull rod and a pull rod sleeve, the pull rod extends from the clamping cover device into the second valve sleeve and is fixedly connected to the valve core, the pull rod sleeve is slidably connected to the pull rod, and the pull rod sleeve is connected to the moving shaft of the linear actuator, and the linear actuator drives the pull rod sleeve and then drives the pull rod to move axially.

[0027] Wherein, the oil filling solenoid valve and the oil draining solenoid valve are respectively normally closed two-position two-way solenoid valves.

[0028] After adopting the above technical solution, the technical effects achieved by the present invention are:

[0029] 1) Since the two adjacent valve stem sections of the valve stem are respectively provided with a rising speed control cone surface and a falling speed control cone surface, when the hydraulic distributor is in the rising working position, the pressure oil chamber of the hydraulic distributor is disconnected from the return oil chamber, and the valve stem forms a rising speed throttling gap with the valve body at the rising speed control cone surface, the first working oil chamber is connected to the pressure oil chamber through the rising speed throttling gap, and the second working oil chamber is connected to the return oil chamber. The axial displacement of the valve stem is controlled by the electronic control unit to change the throttling gap of the rising speed throttling gap. Similarly, when the hydraulic distributor is in the descending working position, the pressure oil chamber of the hydraulic distributor is disconnected from the oil return chamber, the valve stem forms a descending speed throttling gap with the valve body at the descending speed control cone surface, the first working oil chamber is connected to the oil return chamber through the descending speed throttling gap, and the second working oil chamber is connected to the pressure oil chamber. The axial displacement of the valve stem is controlled by the electronic control unit to change the throttling area of ​​the descending speed throttling gap, thereby controlling the descending speed of the agricultural implement.

[0030] At the same time, since the present invention adopts an energy storage oil circuit, the accumulator of the energy storage oil circuit is connected to the first working oil circuit through a first one-way valve, the accumulator is connected to the second working oil circuit through a second one-way valve, and the accumulator is connected to the main oil circuit through a third one-way valve; the hydraulic push rod is connected to the energy storage oil circuit through an oil charging solenoid valve, the hydraulic push rod returns oil and releases pressure through an oil discharge solenoid valve, and the oil charging solenoid valve and the oil discharge solenoid valve are electrically connected to the electronic control unit respectively. Therefore, when the hydraulic distributor is in the rising working position, the falling working position and the middle working position, that is, when the agricultural implement is in the rising state, the falling state and the middle state, the accumulator can be pressurized. Only when the oil charging solenoid valve is powered on and opened, the high-pressure oil in the accumulator pushes the hydraulic push rod, and the hydraulic distributor valve stem moves to the left (as shown in the attached figure). Only when the oil discharge solenoid valve is powered on and opened, the hydraulic oil of the hydraulic push rod is released, and under the action of the return spring, the hydraulic distributor valve stem moves to the right (as shown in the attached figure). The electronic control unit detects the force information of the lower pull rod or the upper pull rod through the force sensor, detects the position information of the lifter through the lifter position sensor, controls the movement of the hydraulic distributor valve stem by controlling the switch of the oil filling solenoid valve and the oil discharge solenoid valve, and feeds back the valve stem position information through the valve stem displacement sensor to realize the lifting, lowering, neutral and floating functions of the agricultural implement. Therefore, the driving force required for the axial movement of the hydraulic distributor valve stem is small and the response speed is fast.

[0031] 2) Since the first working oil circuit is provided with a shut-off valve, in the neutral state, the shut-off valve is closed under the elastic force of the return spring, cutting off the connection between the rodless chamber of the lifting cylinder and the hydraulic distributor, thereby avoiding the sinking of the farm implement due to leakage of the hydraulic distributor.

[0032] Since the valve core of the stop valve of the present invention comprises a first valve core section and a second valve core section with the same outer diameter, an annular groove is arranged between the first valve core section and the second valve core section, the annular groove corresponds to the first cavity position of the first valve sleeve, the first valve core section is slidably matched with the first valve sleeve, the second valve core section is slidably matched with the second valve sleeve, the second valve core sleeve is provided with a flange near the annular groove, the flange is provided with a valve core sealing conical surface, the end of the first valve sleeve is provided with a valve sleeve sealing conical surface, the valve core sealing conical surface and the valve sleeve sealing conical surface have different tapers, and when the return spring is in the state of Under the action of elastic force, when the valve core sealing cone surface presses against the inner edge of the valve sleeve sealing cone surface, the hydraulic oil can fill the inner edge of the valve sleeve sealing cone surface, so that the first chamber is disconnected from the second chamber. Since the outer diameters of the first valve core section and the second valve core section are the same, and the inner diameters of the first valve sleeve and the second valve sleeve are also the same, the force of the hydraulic oil on the valve core in the first chamber is zero, and the force of the hydraulic oil on the valve core in the second chamber is also zero. In this way, to open the valve, it is only necessary to overcome the elastic force of the return spring, and it is completely unaffected by the hydraulic oil flowing through the valve, so the operation is more sensitive and the use is more reliable.

[0033] 3) During the transfer operation, when the hydraulic distributor is in the shock absorbing working position, since a valve stem section of the valve stem of the hydraulic distributor is provided with a throttling step surface, the throttling step surface and the corresponding inner hole of the valve body form a throttling gap that connects the second working oil chamber with the return oil chamber, the pressure oil chamber is connected with the return oil chamber, the first working oil chamber is closed, and the effective cross-sectional areas of the rod chamber and the rodless chamber of the lifting cylinder are different. When the cylinder body of the lifting cylinder instantly moves upward relative to the piston rod, the volume of hydraulic oil flowing out of the rodless chamber is greater than the volume of hydraulic oil required by the rod chamber, and the excess hydraulic oil will flow from the rod chamber through the throttling gap to the return oil chamber; similarly, when the cylinder body of the lifting cylinder instantly moves downward relative to the piston rod of the lifting cylinder, the volume of hydraulic oil flowing out of the rod chamber is insufficient to fill the space vacated by the rodless chamber, so suction will be generated, and the rodless chamber can absorb oil from the return oil chamber through the throttling gap to avoid cavitation.

[0034] 4) In the floating state, neutral state, but the farm implement is grounded for a long time, or in the shutdown state, the accumulator cannot be charged, which may cause the pressure in the accumulator to be very low or even zero. At this time, the electronic control unit can only control the valve stem to move to the right (as shown in the figure), but cannot control the valve stem to move to the left. In order to achieve the purpose of controlling the bidirectional movement of the hydraulic distributor valve stem under these special working conditions, the present invention sets a neutral charging working position and a floating charging working position in the hydraulic distributor. The control unit issues a control instruction to open the oil filling solenoid valve to control the valve stem to move left for a certain period of time (for example, 0.5 seconds). The position sensor detects the displacement of the valve stem. If there is no leftward movement, it is determined that the accumulator is under-pressure, and then the oil discharge solenoid valve is controlled to open. Under the action of the return spring, the valve stem is first pushed to move right to the neutral charging working position or the floating charging working position. After the accumulator is charged, the valve stem is controlled to move left. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 It is a hydraulic principle diagram of an embodiment of an intelligent control system of a hydraulic suspension device of the present invention;

[0036] Figure 2 yes Figure 1 A longitudinal sectional view of the hydraulic distributor in the raised working position;

[0037] Figure 3 yes Figure 1 A longitudinal sectional view of the hydraulic distributor in the shock absorbing working position;

[0038] Figure 4 yes Figure 1 A longitudinal sectional view of the hydraulic distributor in the neutral working position;

[0039] Figure 5 yes Figure 1 A longitudinal sectional view of the middle hydraulic distributor in the neutral pressure-charging working position;

[0040] Figure 6 yes Figure 1 A longitudinal sectional view of the hydraulic distributor in the lowered working position;

[0041] Figure 7 yes Figure 1 A longitudinal sectional view of the hydraulic distributor in the floating working position;

[0042] Figure 8 yes Figure 1 A longitudinal sectional view of the hydraulic distributor in the floating pressurizing working position;

[0043] Fig. 9 yes Figure 2 to Figure 8 A longitudinal cross-sectional view of the middle valve stem;

[0044] Fig.10 yes Figure 1A longitudinal sectional view of the stop valve;

[0045] Fig.11 yes Fig.10 A partial enlarged view of point Ⅰ in the middle;

[0046] Fig.12 yes Fig.10 A longitudinal sectional view of the middle valve core;

[0047] In the figure:

[0048] 001-main oil circuit, 10-stop valve, 101-first valve sleeve, 1011-valve sleeve sealing cone, 101a-first chamber, 101A-first oil port, 102-second valve sleeve, 102b-second chamber, 102B-second oil port, 103-capping device, 104-return spring, 105-valve core, 1051-first valve core section, 1052-second valve core section, 1053-flange, 1053A-valve core sealing cone, 1054-annular groove, 106-pull rod, 107-pull rod sleeve, 108-linear actuator; d-outer diameter, α-angle difference between valve core sealing cone and valve core sealing cone;

[0049] 20-lifting cylinder, 21-first overflow pressure-maintaining valve, 22-second overflow pressure-maintaining valve, 30-hydraulic distributor, 301-valve body, 302-valve stem, 302A-rising speed control cone surface, 302B-descending speed control cone surface, 302C-throttling step surface, 31-reset spring, 32-hydraulic push rod, 41-valve stem displacement sensor, 42-force sensor, 43-lifter position sensor, 44-radar speed sensor, 45-speed sensor, 50-first one-way valve, 60-second one-way valve, 71-oil charging solenoid valve, 72-oil draining solenoid valve, 80-accumulator, 90-third one-way valve;

[0050] A-first working oil port, B-second working oil port, P-pressure oil port, T-return oil port;

[0051] a-first working oil chamber, b-second working oil chamber, p-pressure oil chamber, t-return oil chamber, m-throttling gap. DETAILED DESCRIPTION

[0052] The present invention is further described below in conjunction with the accompanying drawings and embodiments.

[0053] like Figure 1 As shown, an intelligent control system for a hydraulic suspension device can intelligently control the hydraulic suspension device of a tractor, and can also intelligently control the hydraulic suspension device of other agricultural equipment.

[0054] refer to Figure 2The hydraulic distributor 30 includes a valve body 301 and a valve stem 302 arranged in the valve body 301, and the valve body 301 is provided with a first working oil chamber a communicating with the first working oil port A, a second working oil chamber b communicating with the second working oil port B, a pressure oil chamber p communicating with the pressure oil port P and a return oil chamber t communicating with the return oil port T.

[0055] like Figure 1 As shown, the first working oil port A is connected to the rodless chamber of the lifting cylinder 20 through the first working oil circuit, the second working oil port B is connected to the rod chamber of the lifting cylinder 20 through the second working oil circuit, the pressure oil port P is connected to the main oil circuit 001, and the return oil port T is connected to the oil tank. A hydraulic push rod 32 is connected to one end of the valve stem 302, and a return spring 31 is provided at the other end.

[0056] like Fig. 9 As shown, the valve stem 302 is provided with a plurality of valve stem sections for controlling the connection or disconnection of the corresponding oil chambers, wherein two adjacent valve stem sections are respectively provided with a rising speed control cone surface 302A and a falling speed control cone surface 302B, and these two cone surfaces cooperate with the valve body 301 to realize the control of the rising speed and the falling speed of the agricultural implement. Another valve stem section of the valve stem is provided with a throttling step surface 302C, and the throttling step surface 302C and the corresponding inner hole of the valve body 301 form a throttling gap that connects the second working oil chamber b with the return oil chamber t, which is used to compensate for the difference in volume between the rod chamber and the rodless chamber of the lifting cylinder in the shock-absorbing working mode. These two structures are two key points of the present invention, which will be described in detail below.

[0057] like Figure 1 As shown, in order to drive the valve stem 302 of the hydraulic distributor 30 with hydraulic pressure, the intelligent control system of the present invention is provided with an energy storage oil circuit, which includes an accumulator 80, which is connected to the first working oil circuit through a first one-way valve 50, which is connected to the second working oil circuit through a second one-way valve 60, and which is connected to the main oil circuit 001 through a third one-way valve 90; the hydraulic push rod 32 is connected to the energy storage oil circuit through an oil charging solenoid valve 71, which returns oil and releases pressure through an oil discharge solenoid valve 72, the oil charging solenoid valve 71 and the oil discharge solenoid valve 72 are electrically connected to the electronic control unit, respectively, and the oil charging solenoid valve 71 and the oil discharge solenoid valve 72 are preferably normally closed two-position two-way solenoid valves.

[0058] like Figure 1As shown, the force sensor 42 is used to detect the tension information of the lower pull rod or the upper pull rod; the lifter position sensor 43 is used to detect the position information of the lifter; the valve stem displacement sensor 41 is used to detect the displacement information of the valve stem of the hydraulic distributor; the force sensor 42, the lifter position sensor 43 and the valve stem displacement sensor 41 are electrically connected to the electronic control unit respectively. This embodiment also provides a radar speed sensor 44 and a rotation speed sensor 45.

[0059] In order to adapt to the active shock absorption of the mounted agricultural equipment during the field transfer operation, the present invention also provides a shock absorption system. Figure 1 As shown, a first overflow pressure-maintaining branch oil circuit for overflowing and maintaining pressure in the rodless chamber of the lifting cylinder 20 and a second overflow pressure-maintaining branch oil circuit for overflowing and maintaining pressure in the rod chamber of the lifting cylinder 20 are provided between the first working oil circuit and the second working oil circuit; the first overflow pressure-maintaining branch oil circuit includes a first overflow pressure-maintaining valve 21, and the opening pressure of the first overflow pressure-maintaining valve 21 is not less than the pressure of the agricultural implement on the first working oil port A when the hydraulic distributor 30 is in a neutral state; the second overflow pressure-maintaining branch oil circuit includes a second overflow pressure-maintaining valve 22. The working principle of active shock absorption can be found in Chinese invention patent CN111520367A, which will not be described in detail here.

[0060] like Figure 3 As shown, during the transfer operation, the hydraulic distributor 30 is in the shock-absorbing working position, and a valve stem section of the valve stem 302 of the hydraulic distributor is provided with a throttling step surface 302C, and the throttling step surface 302C and the corresponding inner hole of the valve body 301 form a throttling gap m that connects the second working oil chamber b with the return oil chamber t, the pressure oil chamber p is connected with the return oil chamber t, and the first working oil chamber a is closed. Since the effective cross-sectional areas of the rod chamber and the rodless chamber of the lifting cylinder 20 are different, when the cylinder body of the lifting cylinder 20 instantly moves upward relative to the piston rod, the volume of hydraulic oil flowing out of the rodless chamber is greater than the volume of hydraulic oil required by the rod chamber, and the excess hydraulic oil will flow from the rod chamber through the throttling gap m to the oil return chamber t; similarly, when the cylinder body of the lifting cylinder 20 instantly moves downward relative to the piston rod of the lifting cylinder, the volume of hydraulic oil flowing out of the rod chamber is insufficient to fill the space vacated by the rodless chamber, and thus suction will be generated. The rodless chamber can absorb oil from the oil return chamber t through the throttling gap to avoid cavitation.

[0061] like Figure 1 and Fig.10 , 11 and Fig.12 As shown, in order to prevent the hydraulic distributor 30 from leaking oil in a neutral state, a shut-off valve 10 is provided in the first working oil circuit.

[0062] The stop valve 10 includes a valve sleeve, a valve core 105, a return spring 104 and a cover device 103. The valve sleeve includes a first valve sleeve 101 and a second valve sleeve 102 that are axially arranged and fixedly connected together. The return spring 104 is located in the second valve sleeve 102 and clamped between the cover device 103 and the valve core 105.

[0063] The first valve sleeve 101 is provided with a first chamber 101a and a first oil port 101A connected to the first chamber 101a, and the second valve sleeve 102 is provided with a second chamber 102b and a second oil port 102B connected to the second chamber 102b. The first oil port is connected to the first working oil port A of the hydraulic distributor, and the second oil port 102B is connected to the rodless chamber of the lifting cylinder 20. The two can also be swapped, that is, the first oil port 101A is connected to the rodless chamber of the lifting cylinder, and the second oil port 102B is connected to the first working oil port A of the hydraulic distributor. The valve core 105 includes a first valve core section 1051 and a second valve core section 1052 with the same outer diameter d. An annular groove 1054 is provided between the first valve core section 1051 and the second valve core section 1052. The annular groove 1054 corresponds to the position of the first cavity 101a. The first valve core section 1051 is slidably matched with the first valve sleeve 101, and the second valve core section 1052 is slidably matched with the second valve sleeve 102. The second valve core section 1052 is provided with a A flange 1053 is provided, and the flange 1053 is provided with a valve core sealing cone surface 1053A. The end of the first valve sleeve 101 is provided with a valve sleeve sealing cone surface 1011. The taper of the valve core sealing cone surface 1053A is different from that of the valve sleeve sealing cone surface 1011 and has an angle difference α. Under the action of the return spring 104, when the valve core sealing cone surface 1053A presses against the inner edge of the valve sleeve sealing cone surface 1011, the first cavity 101a and the second cavity 102b are disconnected.

[0064] The valve core 105 is connected to the linear actuator 108 through a connecting device. The linear actuator 108 is electrically connected to the electronic control unit. When the linear actuator 108 is energized, it drives the valve core 105 to move, so that the valve core sealing cone surface 1053A is separated from the valve sleeve sealing cone surface 1011, thereby connecting the first chamber 101a with the second chamber 102b. The connecting device includes a tie rod 106 and a tie rod sleeve 107. The tie rod 106 extends from the clamping cover device 104 into the second valve sleeve 102 and is fixedly connected to the valve core 105. The tie rod sleeve 107 is slidably connected to the tie rod 106. The tie rod sleeve 107 is connected to the moving shaft of the linear actuator 108. The linear actuator 108 drives the tie rod sleeve 107 and then drives the tie rod 106 to move axially. The linear actuator 108 can be a linear motor or an electromagnet.

[0065] The free end of the first valve sleeve 101 is exposed as a hydraulic control port, which is connected to the main oil circuit 001. The preset elastic force of the return spring 104 is greater than the thrust of the oil pressure on the valve core 105 when the main oil circuit 001 is in a pressure relief state, but less than the thrust of the oil pressure on the valve core 105 when the main oil circuit 001 is in a high pressure state, that is, when the main oil circuit 001 is in a high pressure state, the hydraulic oil will push open the valve core 105. When the hydraulic distribution valve is in the rising mode or the descending mode, the stop valve 10 will be opened and in a connected state.

[0066] The stop valve 10 is a normally closed stop valve. In the neutral state, the stop valve 10 is closed under the action of the return spring force, cutting off the connection between the rodless chamber of the lifting cylinder 20 and the hydraulic distributor 30, avoiding the settlement of the agricultural implement due to leakage of the hydraulic distributor, and meeting the static settlement requirements of the agricultural implement.

[0067] The taper of the valve core sealing cone 1053A and the valve sleeve sealing cone 1011 are different. Under the action of the return spring 104, when the valve core sealing cone 1053A abuts against the inner edge of the valve sleeve sealing cone 1011, the hydraulic oil can fill the inner edge of the valve sleeve sealing cone, so that the first cavity 101a is disconnected from the second cavity 102b. Since the outer diameters d of the first valve core section 1051 and the second valve core section 1052 are the same, the first valve core section 1051 and the first valve sleeve 101 are slidably matched, and the second valve The core segment 1052 interacts with the second valve sleeve 102, and the outer diameter d of the first valve core segment 1051 is the same as the inner diameter of the first valve sleeve 101, and the outer diameter d of the second valve core segment 1052 is also the same as the inner diameter of the second valve sleeve 102. Therefore, in the first chamber 101a, the force of the hydraulic oil on the valve core 105 is zero, and in the second chamber 102b, the force of the hydraulic oil on the valve core 105 is also zero. In this way, to open the valve, it is only necessary to overcome the elastic force of the return spring, and it is not affected by the hydraulic oil flowing through the valve. The operation is more sensitive and the use is more reliable.

[0068] This embodiment uses a combination of electric control and hydraulic control to control the stop valve 10. The hydraulic control provides a large opening force, is convenient and saves energy, but is affected by the oil pressure of the main oil circuit. The electric control method is not affected by the oil pressure of the main oil circuit and can be used at any time. It is especially irreplaceable when the hydraulic control method cannot be used in the floating state. Of course, if the problem of power consumption is not considered, only the electric control method can be used.

[0069] In this embodiment, the hydraulic distributor is provided with a neutral working position, a neutral pressurizing working position, an ascending working position, a descending working position, a floating working position, a floating pressurizing working position and a shock absorbing working position. Figure 2 to Figure 8 The matching relationship of each component in each working position is shown in sequence.

[0070] like Figure 2 As shown, when the hydraulic distributor 30 is in the rising working position, the pressure oil chamber p is disconnected from the return oil chamber t, the valve stem forms a rising speed throttling gap with the valve body at the rising speed control cone, the first working oil chamber a is connected to the pressure oil chamber p through the rising speed throttling gap, and the second working oil chamber b is connected to the return oil chamber t. The stop valve 10 is opened under the action of the high-pressure oil in the main oil circuit 001. The high-pressure oil in the rodless chamber of the lifting cylinder and the high-pressure oil in the main oil circuit 001 simultaneously charge the accumulator 80. The electronic control unit controls the axial displacement of the valve stem 302, which can control the rising speed of the agricultural implement.

[0071] like Figure 3As shown, when the hydraulic distributor is in the shock absorbing working position, the throttling step surface and the corresponding inner hole of the valve body form a throttling gap m that connects the second working oil chamber b with the return oil chamber t, the pressure oil chamber p is connected with the return oil chamber t, and the first working oil chamber a is closed.

[0072] like Figure 4 As shown, when the hydraulic distributor 30 is in the neutral working position, the pressure oil chamber p is connected to the return oil chamber t, the first working oil chamber a is closed, and the second working oil chamber b is closed. The stop valve 10 is closed, and the high-pressure oil in the rodless chamber of the lifting cylinder is used to charge the accumulator.

[0073] like Figure 5 As shown, when the hydraulic distributor 30 is in the neutral charging position, the pressure oil chamber p is disconnected from the return oil chamber t, the first working oil chamber a is closed, and the second working oil chamber b is closed. The main oil circuit 001 charges the accumulator 80 through the one-way valve 90.

[0074] like Figure 6 As shown, when the hydraulic distributor 30 is in the descending working position, the pressure oil chamber p is disconnected from the return oil chamber t, the valve stem forms a descending speed throttling gap with the valve body at the descending speed control cone, the first working oil chamber a is connected to the return oil chamber t through the descending speed throttling gap, and the second working oil chamber b is connected to the pressure oil chamber p. The stop valve 10 is opened under the action of the high-pressure oil in the main oil circuit 001. The high-pressure oil in the rod chamber of the lifting cylinder and the high-pressure oil in the main oil circuit 001 simultaneously charge the accumulator 80. The electronic control unit controls the axial displacement of the valve stem 302, which can control the descending speed of the agricultural implement.

[0075] like Figure 7 As shown, when the hydraulic distributor 30 is in the floating working position, the pressure oil chamber p, the first working oil chamber a and the second working oil chamber b are respectively connected to the return oil chamber t. The hydraulic oil in the main oil circuit 001 is under pressure, and the electronic control unit controls the linear actuator 108 to move upward (in the direction shown in the figure), overcoming the spring force of the return spring 104 to push the valve core 105 of the stop valve to open.

[0076] like Figure 8 As shown, when the hydraulic distributor is in the floating charging working position, the pressure oil chamber p is disconnected from the oil return chamber t, the first working oil chamber a is connected to the oil return chamber t, and the second working oil chamber b is connected to the oil return chamber t. The main oil circuit 001 charges the accumulator 80 through the one-way valve 90.

[0077] In the present invention, when the hydraulic distributor is in the rising working position, the pressure oil chamber p of the hydraulic distributor 30 is disconnected from the return oil chamber t, the valve stem 302 forms a rising speed throttling gap with the valve body 301 at the rising speed control cone surface 302A, the first working oil chamber a is connected to the pressure oil chamber p through the rising speed throttling gap, and the second working oil chamber b is connected to the return oil chamber t. By controlling the axial displacement of the valve stem 302 by the electronic control unit, the throttling area of ​​the rising speed throttling gap can be changed, thereby controlling the rising speed of the agricultural implement. Similarly, when the hydraulic distributor 30 is in the descending working position, the pressure oil chamber p of the hydraulic distributor is disconnected from the return oil chamber t, the valve stem 302 forms a descending speed throttling gap with the valve body at the descending speed control cone surface 302B, the first working oil chamber a is connected to the return oil chamber t through the descending speed throttling gap, and the second working oil chamber b is connected to the pressure oil chamber p. By controlling the axial displacement of the valve stem 302 by the electronic control unit, the throttling area of ​​the descending speed throttling gap can be changed, thereby controlling the descending speed of the agricultural implement.

[0078] In the present invention, the accumulator 80 can be charged when the hydraulic distributor 30 is in the ascending working position, the descending working position and the middle working position, that is, when the agricultural implement is in the ascending state, the descending state and the middle state. Only when the oil filling solenoid valve 71 is powered on and opened, the high-pressure oil in the accumulator 80 pushes the hydraulic push rod 32, and the hydraulic distributor valve stem 302 moves as shown in the left figure. Only when the oil discharge solenoid valve 72 is powered on and opened, the hydraulic oil of the hydraulic push rod 32 is depressurized, and under the action of the return spring 31, the hydraulic distributor valve stem 302 moves as shown in the right figure. The electronic control unit detects the force information of the lower pull rod or the upper pull rod through the force sensor, detects the position information of the lifter through the lifter position sensor, controls the movement of the hydraulic distributor valve stem by controlling the switch of the oil filling solenoid valve and the oil discharge solenoid valve, and feeds back the valve stem position information through the valve stem displacement sensor to realize the ascending, descending, neutral and floating functions of the agricultural implement. Therefore, the driving force required for the axial movement of the hydraulic distributor valve stem is small and the response speed is fast.

[0079] In the present invention, the accumulator 80 cannot be charged in the floating state, neutral state but the farm implement is grounded for a long time, or in the shutdown state, which may cause the pressure in the accumulator 80 to be very low or even zero. At this time, the electronic control unit can only control the valve stem to move to the right as shown in the figure, but cannot control the valve stem to move to the left. In order to achieve the purpose of controlling the bidirectional movement of the hydraulic distributor valve stem 302 under these special working conditions, the present invention sets a neutral charging working position and a floating charging working position in the hydraulic distributor 30. The control unit issues a control instruction to open the oil filling solenoid valve to control the valve stem 302 to move left for a certain period of time, such as 0.5 seconds, and detects the displacement of the valve stem through the position sensor 41. If there is no leftward movement, it is determined that the accumulator is under-pressure, and then the oil discharge solenoid valve is controlled to open. Under the action of the return spring 31, the valve stem is first pushed to move right to the neutral charging working position or the floating charging working position. After the accumulator is charged, the valve stem is controlled to move left.

[0080] The present invention is not limited to the above embodiments, and all improvements based on the concept, principle, structure and method of the present invention will fall within the protection scope of the present invention.

Claims

1. An intelligent control system for a hydraulic suspension device, comprising: A lifting cylinder and a hydraulic distributor, the hydraulic distributor comprising a valve body and a valve stem arranged in the valve body, the valve body being provided with a first working oil chamber (a) communicating with a first working oil port (A), a second working oil chamber (b) communicating with a second working oil port (B), a pressure oil chamber (p) communicating with a pressure oil port (P) and a return oil chamber (t) communicating with an oil return port (T), the first working oil port (A) being communicated with a rodless chamber of the lifting cylinder through a first working oil circuit, the second working oil port (B) being communicated with a rod chamber of the lifting cylinder through a second working oil circuit, the pressure oil port (P) being communicated with a main oil circuit, and the return oil port (T) being communicated with an oil tank; the hydraulic distributor being provided with a neutral working position, a rising working position, a falling working position and a floating working position; The valve stem is provided with a plurality of valve stem sections for controlling the connection or disconnection of the corresponding oil chambers, one end of the valve stem is connected to a hydraulic push rod, and the other end is provided with a return spring; An energy storage oil circuit, wherein the energy storage oil circuit includes an accumulator, the accumulator is connected to the first working oil circuit through a first one-way valve, the accumulator is connected to the second working oil circuit through a second one-way valve, and the accumulator is connected to the main oil circuit through a third one-way valve; the hydraulic push rod is connected to the energy storage oil circuit through an oil charging solenoid valve, the hydraulic push rod returns oil and releases pressure through an oil discharge solenoid valve, and the oil charging solenoid valve and the oil discharge solenoid valve are electrically connected to an electronic control unit respectively; A force sensor, the force sensor is used to detect the tension information borne by the lower pull rod or the upper pull rod; a lifter position sensor, the lifter position sensor is used to detect the position information of the lifter; The valve stem displacement sensor is used to detect the displacement information of the valve stem of the hydraulic distributor; the force sensor, the lifter position sensor and the valve stem displacement sensor are electrically connected to the electronic control unit respectively; it is characterized in that: Two adjacent valve stem sections of the valve stem are respectively provided with a rising speed control cone surface and a falling speed control cone surface; When the hydraulic distributor is in a neutral working position, the pressure oil chamber (p) is connected to the oil return chamber (t), the first working oil chamber (a) is closed, and the second working oil chamber (b) is closed; When the hydraulic distributor is in the ascending working position, the pressure oil chamber (p) is disconnected from the oil return chamber (t), the valve stem forms an ascending speed throttling gap with the valve body at the ascending speed control cone surface, the first working oil chamber (a) is connected to the pressure oil chamber (p) through the ascending speed throttling gap, and the second working oil chamber (b) is connected to the oil return chamber (t); When the hydraulic distributor is in the descending working position, the pressure oil chamber (p) is disconnected from the return oil chamber (t), the valve stem forms a descending speed throttling gap with the valve body at the descending speed control cone surface, the first working oil chamber (a) is connected to the return oil chamber (t) through the descending speed throttling gap, and the second working oil chamber (b) is connected to the pressure oil chamber (p); When the hydraulic distributor is in a floating working position, the pressure oil chamber (p), the first working oil chamber (a) and the second working oil chamber (b) are respectively connected to the oil return chamber (t); The hydraulic distributor is provided with a neutral pressure-charging working position. When the hydraulic distributor is in the neutral pressure-charging working position, the pressure oil chamber (p) is disconnected from the oil return chamber (t), the first working oil chamber (a) is closed, and the second working oil chamber (b) is closed; The first working oil circuit is provided with a stop valve; The stop valve comprises a valve sleeve, a valve core, a return spring and a gland device, wherein the valve sleeve comprises a first valve sleeve and a second valve sleeve which are axially arranged and fixedly connected together, and the return spring is located in the second valve sleeve and clamped between the gland device and the valve core; The first valve sleeve is provided with a first cavity and a first oil port communicating with the first cavity, and the second valve sleeve is provided with a second cavity and a second oil port communicating with the second cavity; The first oil port is communicated with the first working oil port (A) of the hydraulic distributor, and the second oil port is communicated with the rodless chamber of the lifting cylinder; or The first oil port is communicated with the rodless chamber of the lifting oil cylinder, and the second oil port is communicated with the first working oil port (A) of the hydraulic distributor; The valve core comprises a first valve core section and a second valve core section with the same outer diameter, an annular groove is arranged between the first valve core section and the second valve core section, the annular groove corresponds to the position of the first cavity, the first valve core section is slidably matched with the first valve sleeve, the second valve core section is slidably matched with the second valve sleeve, the second valve core section is provided with a flange near the annular groove, the flange is provided with a valve core sealing cone surface, the end of the first valve sleeve is provided with a valve sleeve sealing cone surface, the valve core sealing cone surface and the valve sleeve sealing cone surface have different tapers, and under the action of the return spring, the valve core sealing cone surface abuts against the inner edge of the valve sleeve sealing cone surface to disconnect the first cavity from the second cavity; The valve core is connected to a linear actuator through a connecting device, and the linear actuator is electrically connected to the electronic control unit. When the linear actuator is energized, it drives the valve core to move, so that the sealing cone surface of the valve core is separated from the sealing cone surface of the valve sleeve, thereby connecting the first cavity with the second cavity.

2. The intelligent control system of the hydraulic suspension device according to claim 1, characterized in that: The hydraulic distributor is provided with a floating pressurizing working position. When the hydraulic distributor is in the floating pressurizing working position, the pressure oil chamber (p) is disconnected from the oil return chamber (t), the first working oil chamber (a) is connected to the oil return chamber (t), and the second working oil chamber (b) is connected to the oil return chamber (t).

3. The intelligent control system of the hydraulic suspension device according to claim 1, characterized in that: A first overflow pressure-maintaining branch oil circuit for overflowing and maintaining pressure in the rodless chamber of the lifting cylinder and a second overflow pressure-maintaining branch oil circuit for overflowing and maintaining pressure in the rod chamber of the lifting cylinder are arranged between the first working oil circuit and the second working oil circuit; the first overflow pressure-maintaining branch oil circuit includes a first overflow pressure-maintaining valve, and the opening pressure of the first overflow pressure-maintaining valve is not less than the pressure of the agricultural implement attached to the first working oil port (A) when the hydraulic distributor is in a neutral state; the second overflow pressure-maintaining branch oil circuit includes a second overflow pressure-maintaining valve.

4. The intelligent control system of the hydraulic suspension device according to claim 3, characterized in that: A valve stem section of the valve stem is provided with a throttling step surface; the hydraulic distributor is provided with a shock absorbing working position. When the hydraulic distributor is in the shock absorbing working position, the throttling step surface and the corresponding inner hole of the valve body form a throttling gap that connects the second working oil chamber (b) with the return oil chamber (t), the pressure oil chamber (p) is connected with the return oil chamber (t), and the first working oil chamber (a) is closed.

5. The intelligent control system of the hydraulic suspension device according to claim 1, characterized in that: The free end of the first valve sleeve is exposed as a hydraulic control port, which is connected to the main oil circuit. The preset elastic force of the return spring is greater than the thrust of the oil pressure on the valve core when the main oil circuit is in a pressure relief state but less than the thrust of the oil pressure on the valve core when the main oil circuit is in a high-pressure state.

6. The intelligent control system of the hydraulic suspension device according to claim 1, characterized in that: The connecting device includes a pull rod and a pull rod sleeve. The pull rod extends from the pressure cover device into the second valve sleeve and is fixedly connected to the valve core. The pull rod sleeve is slidably connected to the pull rod. The pull rod sleeve is connected to the moving shaft of the linear actuator. The linear actuator drives the pull rod sleeve and then drives the pull rod to move axially.

7. The intelligent control system of the hydraulic suspension device according to claim 1, characterized in that: The oil filling solenoid valve and the oil draining solenoid valve are respectively normally closed two-position two-way solenoid valves.

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