A tractor and a lift for a tractor

Abstract

The present invention belongs to the field of agricultural machinery and relates to a tractor lift and a tractor equipped with the same. By specifically setting the distributor in the lift, especially the automatic actuator of the lift distributor, the lift arm component of the tractor lift is driven to move the implement to the position required for operation by changing the flow rate and direction of the hydraulic oil. On the basis of ensuring stability and high efficiency, the manufacturing and use costs are reasonably controlled.

Description

Technical Field

[0001] The present invention belongs to the field of agricultural machinery, and particularly relates to a tractor and a lift for a tractor. Background Art

[0002] In order to lift, lower or maintain the position of the implements suspended behind the tractor, the intelligence, stability, high efficiency and low cost of the lift, which is part of the tractor components, are relatively important requirements. The existing electronically controlled lift generally controls the reciprocating motion of the hydraulic cylinder through an electronically controlled valve by an electronic controller, so as to control the lifting, lowering and maintaining the position of the lifting arm of the farm implement. However, the existing electronically controlled lifts are either too costly or their stability and efficiency do not meet the requirements of tractor use, and they are prone to become the short board of the tractor operation efficiency. Therefore, on the basis of ensuring high stability and high efficiency, a lift with relatively low cost has become an urgent problem to be solved in this field.

[0003] The Chinese invention patent application publication text CN112352490A discloses a double-cylinder hydraulic lift for a tractor. By setting the double-cylinder hydraulic pressure, the reliability is improved, and the problems of valve jamming and oil circuit blockage are improved. However, its stability and efficiency need to be improved. The Chinese invention patent application publication text CN113446281A discloses a lift distributor for a tractor. By specifically setting the inside of the distributor, a stable connection between the oil supply pipeline and the oil port is achieved without increasing the space of the distributor. However, the functionality and stability of this distributor for use behind the tractor need to be improved. Summary of the Invention

[0004] Aiming at the above technical problems, the object of the present invention is to provide a tractor lift that is electronically controlled, low-cost, highly reliable, less sensitive to the cleanliness of hydraulic oil, and can realize the controlled speed lifting and lowering of implements with different weights.

[0005] It is achieved by the following technical means:

[0006] A lift for a tractor, the tractor includes a drive motor, and the drive motor transmits power to the lift to drive the implement hung on the lift to different working positions.

[0007] The lifter includes a hydraulic pump, a distributor, two or more lifting cylinders, a lifting arm component, two or more lifting rods, an upper pull rod, two or more lower pull rods, a lifting motor, a rotary reduction mechanism for reducing the output speed of the lifting motor, a linear reciprocating mechanism for converting the rotary motion output by the rotary reduction mechanism into a linear motion, a controller group, and a sensor group; the lifting motor is connected to the rotary reduction mechanism in a direct or indirect connection manner, the rotary reduction mechanism and the linear reciprocating mechanism are arranged in series, and the linear reciprocating mechanism is connected to the distributor in a direct or indirect connection manner; the hydraulic pump receives the power of the drive motor, the hydraulic pump is provided with a hydraulic pump inlet and a hydraulic pump outlet, the inlet of the hydraulic pump is connected to the hydraulic oil tank through a pipeline, and the outlet is connected to the distributor through a pipeline, and the distributor is connected to two or more lifting cylinders through pipelines respectively.

[0008] The distributor includes a distributor valve seat, a distributor spool, and a hydraulic lock. A long through hole is provided in the distributor valve seat. The distributor valve seat is provided with an oil inlet, an oil return port, a lifter rising oil port, a lifter falling oil port, and an oil return cavity connected to the oil return port. The oil inlet, the oil return port, and the oil return cavity are respectively communicated with the long through hole. The oil inlet is connected to the outlet of the hydraulic pump, and the oil return port is connected to an external oil tank through a pipeline. The lifting cylinder includes a first cavity and a second cavity. The lifter rising oil port is connected to the first cavities of two or more lifting cylinders through pipelines respectively, and the lifter falling oil port is connected to the second cavities of two or more lifting cylinders through pipelines respectively; the distributor spool is of a rotary body structure and includes three or more large-diameter sealed large cylindrical surfaces and small-diameter oil-passing small cylindrical surfaces for oil passing arranged between the large-diameter sealed large cylindrical surfaces; the outer diameter of the sealed large cylindrical surface is D, where D > P / 65, the unit of D is millimeter, and P is the rated maximum total power of the drive motor, the unit of P is kilowatt (kW); the diameter of the oil-passing small cylindrical surface is d, where d < D / 1.1. The distributor spool is sleeved in the long through hole of the distributor valve seat, and one end of the distributor spool is connected to the linear reciprocating mechanism in a direct or indirect manner (such as a pin shaft or a ball pin).

[0009] The displacement or maximum displacement of the hydraulic pump is S, where S > P / 8, where P is the rated maximum total power of the drive motor, the unit of P is kilowatt (kW); the unit of S is ml / r.

[0010] As an implementation manner, one end of each of the lifting cylinders is fixed to the tractor body directly or indirectly, and the other end is connected to the lifting arm component in a manner that only allows relative rotation (such as a pin shaft). The lifting arm component includes a lifting arm shaft and more than two lifting arms. The lifting arm shaft is connected to the tractor body in a manner that only allows relative rotation. Each lifting arm includes two lifting arm ends. The first lifting arm end is connected to the lifting cylinder, and the second lifting arm end is connected to the lifting rod in a manner that only allows relative rotation (such as a pin shaft). Each of the lifting rods is connected to the lower link in a manner that only allows relative rotation (such as a pin shaft). Each of the lower links is provided with hinge points A, B, and C. The hinge point A is arranged between the hinge points B and C. Each of the lifting rods is hinged to the corresponding lower link at the hinge point A. The lower link is hinged to the tractor body directly or indirectly at the hinge point B, and the lower link is connected to the implement at the hinge point C. The sensor includes at least one position sensor.

[0011] Preferably, the distributor spool is provided with a spool conical surface with the axis of the distributor spool as the axis of rotation. The angle between the generatrix of the spool conical surface and the axis of the distributor spool is less than 60° or greater than 120°.

[0012] The hydraulic lock is of a mechanical-hydraulic lock structure, including a push rod, a sealing body, an elastic reset element, a one-way valve spool, and a one-way valve seat. One end of the spool conical surface is a small cylindrical surface of the conical surface, and the other end is a large cylindrical surface of the conical surface. The spool conical surface can abut against one end of the push rod. The push rod is arranged in the distributor valve seat, and the axis of the push rod is perpendicular or nearly perpendicular to the axis of the distributor spool. The end of the push rod that does not abut against the spool conical surface is a small-diameter push rod end, and the diameter of the small-diameter push rod end is smaller than the diameter of the end of the push rod that abuts against the spool conical surface. An axial through hole is provided in the one-way valve spool, and the axial through hole is a large-diameter through hole and a small-diameter through hole that are interconnected. The connection between the large-diameter through hole and the small-diameter through hole is a through-hole step or a through-hole transition conical surface. The length of the small-diameter through-hole end of the one-way valve spool is L1, and the length of the small-diameter push rod end is L2, satisfying L1 - L2 ≤ 2 mm. The end of the small-diameter push rod end abuts against the sealing body arranged in the axial through hole. A sealing surface is provided between the end of the one-way valve spool far from the push rod and the one-way valve seat. The one-way valve seat is sleeved in the lift cylinder up oil port of the distributor valve seat. The large-end diameter of the sealing surface between the one-way valve spool and the one-way valve seat is D1, and the diameter of the small-diameter through hole is D2, satisfying One end of the elastic reset element abuts against the sealing body in the axial through hole, and the other end of the elastic reset element is directly or indirectly fixed to the distributor valve seat.

[0013] When the contact position between the ejector rod and the distributor valve core is on the small cylindrical surface, the elastic reset element presses the seal body against the through-hole step, and the seal body presses the ejector rod against the distributor valve core, and the hydraulic oil cannot flow through the axial through-hole of the one-way valve core; when the distributor valve core moves axially and the contact position between the ejector rod and the distributor valve core is on the conical surface, the ejector rod is driven by the conical surface of the valve core to move axially, pushing the seal body to separate from the through-hole step, and the hydraulic oil can flow through the axial through-hole of the one-way valve core; when the distributor valve core continues to move axially and the contact position between the ejector rod and the distributor valve core is on the first large cylindrical surface, while the end of the small-diameter end of the ejector rod abuts against the seal body, the shaft step of the ejector rod also abuts against the one-way valve core, pushing the seal body to separate from the through-hole step and at the same time pushing the sealing surface between the one-way valve core and the one-way valve seat to separate, and the hydraulic oil can flow through the axial through-hole of the one-way valve core and can also flow through the one-way valve seat.

[0014] Preferably, the oil inlet, the lift cylinder lowering oil port, and the oil return port are sequentially communicated with the long through-hole, and the distributor valve core is further provided with a second large cylindrical surface, and the oil inlet on the valve seat communicates with the long through-hole at a position between the first large cylindrical surface and the second large cylindrical surface; when the distributor valve core moves axially and the contact position between the ejector rod and the distributor valve core is on the first large cylindrical surface, the second large cylindrical surface is located between the oil inlet and the lowering oil port, so that the oil inlet communicates with the rising oil port; when the distributor valve core moves axially and the contact position between the ejector rod and the distributor valve core is on the valve core conical surface, the second large cylindrical surface is at the lowering oil port and closes the lowering oil port; when the distributor valve core moves axially and the contact position between the ejector rod and the distributor valve core is on the small cylindrical surface, the second large cylindrical surface is located between the lowering oil port and the oil return port, so that the oil inlet communicates with the lowering oil port.

[0015] Preferably, the hydraulic pump drives the hydraulic oil to flow into the distributor through the oil inlet, and the distributor valve core distributes the hydraulic oil to different oil outlets by axially moving, driving the lift cylinder to perform actions of extending, retracting or maintaining the position; then the lift cylinder performs actions of lifting, lowering or maintaining the first lift arm end of the lift arm component, the second lift arm end drives the lift rod, the lift rod drives the lower pull rod, one end is connected to the implement, and the other end is connected to the box body by a way of only mutual rotation (such as a pin shaft), so as to drive the implement suspended on the lower pull rod to perform actions of lifting, lowering or maintaining the position.

[0016] As a replacement, the hydraulic lock is an electronically controlled hydraulic lock structure, including a linear motor and a pushable one-way valve; the pushable one-way valve includes a sealing surface, a sealing body and an elastic reset element; the elastic reset element presses the sealing body against the sealing surface; when the linear motor is not actuated, the elastic reset element presses the sealing body against the sealing surface, and hydraulic oil cannot flow through the hydraulic lock structure, realizing the locked state of the hydraulic lock; when the linear motor is actuated, the sealing body is separated from the sealing surface, and hydraulic oil can flow through the hydraulic lock structure, realizing the open state of the hydraulic lock.

[0017] Preferably, the sensor group includes a lifting position sensor; the lifting position sensor is an angle sensor, the angle sensor includes at least one rotatable measuring rotating shaft, and the angle sensor is connected to the lifting arm component through at least one angle sensor swing arm mounted on the measuring rotating shaft. The effective length of the angle sensor swing arm is greater than 10 mm, and the effective length is the distance from the rotation center of the measuring rotating shaft of the angle sensor to the end of the angle sensor swing arm; the measuring rotating shaft of the angle sensor is connected to the angle sensor swing arm and rotates together, the angle sensor swing arm is connected to the lifting arm component and rotates together, and the measuring range of the angle sensor is at least 10°.

[0018] Preferably, the controller group includes at least one controller. The controller group receives the signal of the angle sensor to obtain the current position of the lifter, compares it with the gap from the target position of the lifter, drives the lifting motor, and directly or indirectly moves the distributor spool to the required position through the reduction mechanism and the linear reciprocating mechanism, and then pushes the lifting oil cylinder to act, pushing the lifting arm component to drive the tool to the target position.

[0019] Preferably, the sealing surface between the one-way valve spool and the one-way valve seat is a conical surface, and the small end surface of the conical surface of the one-way valve spool faces the direction of the distributor spool; the sealing body is a sphere, and the elastic reset element is a helical spring; the distance between the through-hole step and the small cylindrical surface of the distributor spool is greater than or equal to the length of the ejector rod (preferably equal).

[0020] Preferably, 1 or more pressure buffer ports are arranged at the edge of at least one large sealing cylindrical surface of the distributor spool; the pressure buffer ports form 1 or more notches at the edge of the large sealing cylindrical surface, and the total arc length of the projection of the 1 or more notches on the outer circle of the end surface of the large sealing cylindrical surface is L, where L > D × P / 8000, the unit of L is millimeter, where P is the rated maximum total power of the drive, and the unit is kilowatt (kW); the length or height of the pressure buffer port in the axial direction of the distributor spool is greater than 2 mm; the change trend of the cross-sectional area of the pressure buffer port is monotonically changing along the axial direction, and the cross-sectional area of the pressure buffer port is the area of the projection of the pressure buffer port on the surfaces at different positions perpendicular to the axis of the distributor spool.

[0021] As an implementation manner, the surface hardness of the sealed large cylindrical surface is greater than HRC55.

[0022] Preferably, the rated power of the lifting motor is Pd, with the unit of kilowatt (kW), where Pd > P / 6000; where P is the rated maximum power of the drive.

[0023] Preferably, the drive is an engine, a motor, or a combination of an engine and a motor.

[0024] Preferably, the drive is one or a combination of an internal combustion engine, an external combustion engine, a jet engine, a generator, or a motor.

[0025] Preferably, the drive is an engine or more than 1 motor (for example, when the tractor is an extended-range tractor, 2 motors can be specifically set, the 2 motors are connected to the same power source, and the hydraulic pump receives the power of one of the motors).

[0026] Preferably, when there are 2 or more drives, P is the rated maximum power of the one with the smaller rated power among them, with the unit of kilowatt (kW).

[0027] Preferably, the total reduction ratio of the rotary reduction mechanism is i1, and the total reduction ratio of the rotary reduction mechanism is the output speed of the lifting motor / the output speed of the reduction mechanism; the linear reciprocating mechanism is one or a combination of a lead screw mechanism, a ball screw mechanism, a sliding screw mechanism, a rack and pinion mechanism, or a connecting rod mechanism; the conversion ratio of the linear reciprocating mechanism is i2, and the conversion ratio of the linear reciprocating mechanism is the ratio between linear motion and rotation, with the unit of mm / r, and the i1 and i2 satisfy:

[0028] 0.006mm / r < < 42mm / r.

[0029] Preferably, a distributor arm is connected to one end of the distributor spool, the linear reciprocating mechanism is connected to the distributor through a push-pull flexible shaft, the distributor arm, and the diameter of the push-pull flexible shaft is Dsa, where Dsa > P / 100, the unit of Dsa is mm, and P is the rated maximum total power of the drive, with the unit of kilowatt (kW).

[0030] Preferably, the motor is connected to the lead screw through a reduction gear set, the lead screw is sleeved on the nut in a manner that can axially move relative to each other, the nut abuts against one end of the push-pull flexible shaft, the distributor arm is a sheet-like structure, one end of the distributor arm is hinged to the push-pull flexible shaft (for example, connected by a pin shaft), and the other end is hinged to the distributor spool (for example, connected by a pin shaft).

[0031] Preferably, the sensor group further includes at least one stroke measurement mechanism, which is connected to the lifting motor and / or the rotary reduction mechanism or the linear reciprocating mechanism. The stroke measurement mechanism is used to measure the number of revolutions of the motor, the number of revolutions of the gear or other rotating bodies, or the number of revolutions or linear stroke of the linear reciprocating mechanism.

[0032] Preferably, the stroke measurement mechanism is connected to the linear reciprocating mechanism by a grating or a linear potentiometer.

[0033] Preferably, the angle sensor is arranged between the linear reciprocating mechanism and the distributor through an angle sensor swing arm. The effective length of the angle sensor swing arm is greater than 20 mm. The effective length is the distance between the rotation center of the angle sensor and the end of the angle sensor swing arm.

[0034] Preferably, 2 limit position detection mechanisms (preferably touch switches) are also arranged on the linear reciprocating mechanism.

[0035] Preferably, the controller cooperates with the stroke measurement mechanism to calibrate the lifting speed of the distributor. Specifically, the lifting motor is driven. The controller makes the spool of the distributor move axially to the required position. The oil fluid with a specific flow rate flows into or out of the two lifting oil cylinders, thereby pushing the lifting arm component of the lifter to the target position. The controller group receives the signals of the position sensors, obtains the distance between the current position of the lifter and the target position of the lifter, sets the moving speed of the lifter oil cylinder, and obtains the relationship between the lifting speed and the position of the spool of the distributor according to the input signal of the stroke measurement mechanism.

[0036] Preferably, the lifting rod is of a nut and screw structure. The nut is threadedly connected to the screw. The screw end of the lifting rod is hinged to the distributor arm (for example, connected by a pin shaft). The nut end of the lifting rod is hinged to the lower pull rod (for example, connected by a pin shaft).

[0037] A tractor is provided with the above-mentioned tractor lifter.

[0038] The technical effects of the present invention are as follows:

[0039] 1. By specifically setting the distributor and pulling the spool of the distributor by the motor, the movement speed of the lifter under different loads can be controlled at a lower cost, different weight implements can be adapted, different lifting and lowering speeds can be achieved, and it has a high level of intelligence. The lifter also has a floating function, that is, when the spool of the distributor moves to the floating position, the hydraulic oil can freely flow in and out of the oil cylinder, and the position of the oil cylinder follows the external load. At the same time, by defining the size of the one-way spool, a higher tolerance for the cleanliness of the hydraulic oil is ensured.

[0040] 2. By specifically setting the structure of the hydraulic lock, especially the specific cooperation setting of the ejector rod with the seal body, check valve seat, and check valve core, the present invention can effectively maintain the lifter and the implement in the current position. At the same time, it reduces the force required to open the check valve, indirectly reducing the power requirement for the lifting motor. Based on the fact that the traditional check valve can only allow oil to flow in one direction, the switching between one-way oil flow and two-way oil flow can be achieved at a relatively low cost.

[0041] 3. The present invention is provided with a distributor spool composed of a plurality of large cylindrical surfaces and a plurality of small cylindrical surfaces. Combining the cooperation of the lifter rising oil port, oil inlet, lifter descending oil port, and oil return port with the position of the long through hole, the working state is switched through mechanical settings, and the flow control is achieved through the adjustment of the sealing surface ratio. It is not sensitive to the cleanliness of the hydraulic oil, greatly improving the reliability of the electric control lifter.

[0042] 4. By reasonably setting a pressure buffer port at a specific position on the distributor spool and specifically setting its dimensional ratio, the pressure change is relatively gentle, reducing the impact of pressure and flow changes on the device. It also makes the operation of the implement more stable, thereby not only improving the overall system life but also reducing the waste of seeds, fertilizers, pesticides, etc. caused by the jitter of the implement. At the same time, it reduces the probability of mis-sowing and mis-spreading, improves the operation quality, and makes the lifter of the present invention more suitable for the use of tractors.

[0043] 5. By setting a push-pull flexible shaft, the protection of components with high environmental requirements can be achieved, and different system layouts can also be adapted, reducing costs. More importantly, by setting the size of the push-pull flexible shaft (the proportional relationship between the flexible shaft size and the driving power), the stiffness and strength of the overall device are ensured, improving the performance and reliability of the system.

[0044] 6. By setting the structure of the sensor, the requirement for the machining accuracy of the lifting arm is reduced, and the robustness and reliability of the system are improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Figure 1 It is a schematic connection layout diagram of an embodiment of the lifter for a tractor according to the present invention.

[0046] Figure 2 It is a schematic diagram of the rear connection components of an embodiment of the lifter for a tractor according to the present invention.

[0047] Figure 3 It is a two-dimensional schematic diagram of the sectional structure when the distributor is in the rising position.

[0048] Figure 4 It is a two-dimensional schematic diagram of the sectional structure when the distributor is in the locked position.

[0049] Figure 5A two-dimensional schematic diagram of the sectional structure when the dispenser is in the lowered position.

[0050] Figure 6 A two-dimensional schematic diagram of the sectional structure when the dispenser is in the floating position.

[0051] Figure 7 A three-dimensional structural schematic diagram of the dispenser spool.

[0052] Figure 8 A two-dimensional unfolded schematic diagram of the mechanical hydraulic lock structure.

[0053] Wherein: 1. fuel tank, 2. hydraulic pump, 3. reduction mechanism, 4. lead screw, 5. lifting motor, 6. touch switch, 7. nut, 8. push-pull flexible shaft, 9. stroke measuring mechanism, 10. swing arm of the stroke measuring mechanism, 11. dispenser arm, 12. dispenser, 12-1. sealing ring, 12-2. check valve seat, 12-3. check valve core, 12-4. upward oil port, 12-5. elastic reset element, 12-6. sealing body, 12-7. downward oil port, 12-8. oil return port, 12-9. dispenser spool, 129-1. first large sealing cylindrical surface, 129-2. second large sealing cylindrical surface, 129-3 third large sealing cylindrical surface, 129-4. small conical cylindrical surface, 129-5. spool conical surface, 129-6. large conical cylindrical surface, 129-7. pressure buffer port, 12-10. dispenser valve seat, 12-11. oil inlet, 12-12. ejector rod, 12-13. oil return cavity, 13. lifting position sensor, 14. swing arm, 15. lifting arm component, 16. upper pull rod, 17. lifting rod, 18. lifting cylinder, 19. lower pull rod, 19-1. hinge point B, 19-2. hinge point A, 19-3. hinge point C. Detailed implementation manners

[0054] The following further illustrates the technical solution of the present invention by combining embodiments and drawings. Unless otherwise stated, each feature is only an example among a series of equivalent or similar features. It is only for helping to understand the present invention. Those skilled in the art should understand that the described embodiments are only for helping to understand the present invention and should not be regarded as a specific limitation to the present invention.

[0055] A lift for a tractor, the tractor includes a drive motor, and the output end of the drive motor transmits power to the lift in a direct connection or indirect connection manner, so that the lift can suspend the implement on the lift and drive the implement to the working position of the implement by the lift to complete the operation of the implement.

[0056] Such as Figure 1 And Figure 2As shown in the figure, the lifter includes a hydraulic pump, a distributor, two lifting cylinders, a lifting arm component, two lifting rods, an upper pull rod, two lower pull rods, a lifting motor, a rotary reduction mechanism, a linear reciprocating mechanism that converts rotary motion into linear motion, a controller group, and a sensor; the lifting motor is connected to the rotary reduction mechanism in a direct or indirect connection manner, the rotary reduction mechanism and the linear reciprocating mechanism are arranged in series, and the linear reciprocating mechanism is connected to the distributor in a direct or indirect connection manner; the hydraulic pump receives the power of the driving machine in a direct connection or fixed speed ratio manner, the hydraulic pump is provided with an oil inlet and an oil outlet, the oil inlet of the hydraulic pump is connected to the hydraulic oil tank through a pipeline, the oil outlet is connected to the distributor through a pipeline, the distributor is connected to the two lifting cylinders through pipelines respectively, one end of each lifting cylinder is fixed to the tractor body in a direct or indirect manner, and the other end is connected to the lifting arm component in a manner that only allows relative rotation (such as a pin shaft), the lifting arm component includes a lifting arm shaft and two lifting arms, the lifting arm shaft is connected to the tractor body in a manner that only allows relative rotation, each lifting arm includes two lifting arm ends, wherein the first lifting arm end is connected to the lifting cylinder, and the second lifting arm end is connected to the lifting rod in a manner that only allows relative rotation (such as a pin shaft), each lifting rod is connected to the lower pull rod in a manner that only allows relative rotation (such as a pin shaft), each lower pull rod is provided with hinge points A, B, and C, the hinge point A is arranged between the hinge points B and C, each lifting rod is hinged to the corresponding lower pull rod at the hinge point A, the lower pull rod is hinged to the tractor body at the hinge point B in a direct or indirect manner, and the lower pull rod is connected to the implement at the hinge point C; one end of the upper pull rod is connected to the implement, and the other end is connected to the box body in a manner that only allows relative rotation (such as a pin shaft); the sensor includes 1 position sensor.

[0057] As Figure 3 shown in the figure, the distributor includes a distributor valve seat, a distributor spool, and a hydraulic lock. A long through hole is provided in the distributor valve seat, and an oil inlet, an oil return port, a lifter rising oil port, a lifter falling oil port, and an oil return cavity connected to the oil return port are provided on the valve seat. Each of the oil ports and the oil return cavity is communicated with the long through hole. The oil inlet is connected to the oil outlet of the hydraulic pump through a pipeline, the oil return port is connected to an external oil tank through a pipeline, the lifting cylinder includes a first cavity and a second cavity, the rising oil port is connected to the first cavity of the lifting cylinder through a pipeline, and the falling oil port is connected to the second cavity of the lifting cylinder through a pipeline. As Figure 7As shown in the figure, the dispenser spool is of a rotary body structure, including five large-diameter large cylindrical surfaces for sealing and small-diameter small cylindrical surfaces for oil passage arranged between the large-diameter large cylindrical surfaces; the outer diameter D of the sealing large cylindrical surface is 18 mm, and the rated maximum total power P of the driving machine is 117.6 KW, meeting the requirement of D > P / 65; the diameter d of the oil-passing small cylindrical surface is 8.7 mm, meeting the requirement of d < D / 1.1; the dispenser spool is sleeved in the long through-hole of the valve seat, and one end of the dispenser spool is connected to the linear reciprocating mechanism directly or indirectly (such as a pin shaft or a ball head).

[0058] As Figure 8 shown in the figure, the hydraulic lock is of a mechanical-hydraulic lock structure, including a push rod, a sealing body, an elastic reset element, a one-way spool, a one-way valve seat and a sealing ring; a spool conical surface with the axis of the dispenser spool as the rotation axis is arranged on the dispenser spool, the angle between the conical surface generatrix of the spool conical surface and the axis of the dispenser spool is 38°, one end of the spool conical surface is the dispenser spool of the first small cylindrical surface, and the other end of the spool conical surface is the dispenser spool of the first large cylindrical surface. The circumferential position of the spool conical surface abuts against one end of the push rod. The push rod is arranged in the valve seat, and the axis of the push rod is perpendicular to the axis of the dispenser spool. The other end of the push rod forms a small-diameter push rod end through a shaft step. An axial through-hole is arranged in the one-way spool, and the axial through-hole is a large-diameter through-hole at one end and a small-diameter through-hole at the other end connected, and the connection part is a through-hole step. The length L1 of the small-diameter through-hole end of the one-way spool is 2.6 mm, and the length L2 of the small-diameter push rod end is 2.5 mm, meeting the requirement of L1 - L2 ≤ 2. The end of the small-diameter push rod end abuts against the sealing body arranged in the axial through-hole; a sealing surface is arranged between the other end of the one-way spool and the one-way valve seat. The one-way valve seat is sleeved in the rising oil port of the valve seat, and a sealing ring is arranged between the one-way valve seat and the valve seat. The large-end diameter D1 of the sealing surface of the one-way spool and the one-way valve seat is 14.5 mm, and the small-end diameter D2 of the axial through-hole of the one-way spool is 1 mm, meeting the requirement of ; one end of the elastic reset element (such as a spring) abuts against the sealing body (such as a sphere) in the axial through-hole, and the other end of the elastic reset element is fixed to the dispenser valve seat directly or indirectly (such as Figure 3The present embodiment shown is connected to the distributor valve seat through a threaded baffle. The end of the threaded baffle abuts against and is fixed to the elastic reset element. The outer circumference of the threaded baffle is spirally connected to the rising oil port in the distributor valve seat. When the contact position between the ejector rod and the distributor valve core is on the small cylindrical surface, the elastic reset element presses the seal body against the through-hole step, and the seal body presses the ejector rod against the distributor valve core, and hydraulic oil cannot flow through the axial through-hole of the one-way valve core. When the distributor valve core moves axially and the contact position between the ejector rod and the distributor valve core is on the conical surface, the ejector rod is driven by the conical surface of the valve core to move axially, pushing the seal body to separate from the through-hole step, and hydraulic oil can flow through the axial through-hole of the one-way valve core. When the distributor valve core continues to move axially and the contact position between the ejector rod and the distributor valve core is on the first large cylindrical surface, while the end of the small-diameter ejector rod end abuts against the seal body, the shaft step of the ejector rod also abuts against the one-way valve core, pushing the seal body to separate from the through-hole step and at the same time pushing the sealing surface between the one-way valve core and the one-way valve seat to separate, and hydraulic oil can flow through the axial through-hole in the one-way valve core and can also flow through the one-way valve seat.

[0059] As Figure 3-6 shown, the rising oil port, the oil inlet port, the falling oil port, and the oil return port in the distributor valve seat are sequentially communicated with the long through-hole. Among them, a oil return cavity connected to the oil return port is arranged in the valve seat in the opposite direction of the oil return port relative to the rising oil port; As Figure 7 shown, the distributor valve core includes 5 sealed large cylindrical surfaces. Among them, the first sealed large cylindrical surface moves between the oil return cavity and the rising oil port, the second sealed large cylindrical surface moves between the oil inlet port and the falling oil port, and the third sealed large cylindrical surface moves between the falling oil port and the oil return port; As Figure 3 shown, when the contact position between the ejector rod and the distributor valve core is at the upper end of the conical small cylindrical surface, the first large cylindrical surface abuts against the oil return cavity, the second large cylindrical surface disconnects the oil passage between the oil inlet port and the falling oil port, the oil inlet port is communicated with the rising oil port, and the falling oil port is communicated with the oil return port; As Figure 4 shown, when the distributor valve core moves axially so that the contact position between the ejector rod and the distributor valve core is at the lower end of the conical small cylindrical surface, the first large cylindrical surface abuts against the oil return cavity, the second large cylindrical surface abuts against the oil inlet port, the oil inlet port does not admit oil, the rising oil port is independent, and the falling oil port is independent; As Figure 5 shown, when the distributor valve core moves axially so that the contact position between the ejector rod and the distributor valve core is at the upper end of the conical large cylindrical surface, the first large cylindrical surface does not abut against the oil return cavity, the second large cylindrical surface is located between the oil inlet port and the rising oil port and disconnects the oil passage between the oil inlet port and the rising oil port, so that the oil inlet port is communicated with the falling oil port, and the oil return port is communicated with the rising oil port; As Figure 6As shown, when the axial movement of the dispenser spool causes the contact position between the ejector rod and the dispenser spool to be at the lower end of the large cylindrical surface of the conical surface, the first large cylindrical surface does not abut against the oil return cavity, the second large cylindrical surface is located between the oil inlet and the rising oil port to disconnect the oil passage between the oil inlet and the rising oil port, and the third large cylindrical surface is located between the oil inlet and the lowering oil port to disconnect the oil passage between the oil inlet and the lowering oil port, so that the rising oil port is communicated with the lowering oil port through the oil return cavity and the oil return port.

[0060] The hydraulic pump drives hydraulic oil to flow into the dispenser through the oil inlet. The dispenser spool axially moves to distribute the hydraulic oil to the rising oil port and / or the lowering oil port, driving the lifting cylinder to perform actions of extending, retracting, floating or maintaining position; then the lifting cylinder performs actions of lifting, lowering, being controlled by the implement or maintaining the first lifting arm end of the lifting arm component. The second lifting arm end drives the lifting rod, the lifting rod drives the lower pull rod, and the upper pull rod is also connected to the implement, thereby driving the implement suspended on the lower pull rod to perform actions of lifting, lowering, floating or maintaining position.

[0061] The position sensor is an angle sensor, and the angle sensor is arranged on the lifting arm component and the lower pull rod, and the measurement range of the angle sensor is at least 10°.

[0062] The controller group includes 1 controller. The controller group receives the signal of the angle sensor to obtain the current position of the lift and compares it with the difference from the target position of the lift, drives the lift motor, and directly or indirectly moves the dispenser spool to the required position through the reduction mechanism and the linear reciprocating mechanism, and then pushes the lifting cylinder to act, pushing the lifting arm component to drive the implement to the target position.

[0063] The sealing surface between the one-way spool and the one-way valve seat is a conical surface, and the small end surface of the conical surface of the one-way spool faces the direction of the dispenser spool; the sealing body is a sphere, and the elastic reset element is a helical spring; the distance between the through-hole step and the small cylindrical surface of the dispenser spool is equal to the length of the ejector rod.

[0064] As Figure 7 shown, 4 pressure buffer ports symmetrically distributed with the axis of rotation of the large cylindrical surface as the axis of symmetry are arranged at the edges of the 5 large cylindrical surfaces; the pressure buffer ports form notches at the edges of the large cylindrical surfaces, and the projected arc length L of the notches on the circle formed at the edge of the small cylindrical surface is 6.77 mm, satisfying L > D × P / 8000, where P is the rated maximum total power of the drive, which is 117.6 KW; the surface hardness of the large cylindrical surface is greater than HRC55.

[0065] The rated power Pd of the lift motor is 60 W, satisfying Pd > P / 6000, where the rated maximum total power P of the drive is 117.6 KW.

[0066] The driving machine in this embodiment is an internal combustion engine.

[0067] The speed reduction mechanism is more than one set of gear speed reduction mechanisms, the total speed reduction ratio i1 of the speed reduction mechanism is 10, the linear reciprocating mechanism is a lead screw mechanism, the conversion rate i2 of the linear reciprocating mechanism is 2 mm / r, and the conversion rate of the linear reciprocating mechanism is the ratio between linear motion and rotation. The i1 and i2 satisfy 0.006 mm / r < < 42 mm / r; A distributor arm is connected to one end of the distributor spool. The linear reciprocating mechanism is connected to the distributor through a push-pull flexible shaft and the distributor arm. The diameter Dsa of the flexible shaft is 3.2 mm, satisfying Dsa > P / 100.

[0068] The motor in this embodiment is connected to the lead screw through a speed reduction gear set. The lead screw is sleeved on the nut in a manner that can axially move relative to each other. The nut abuts against one end of the push-pull flexible shaft. The distributor arm is a sheet-like structure. One end of the distributor arm is connected to the push-pull flexible shaft through a pin shaft, and the other end is connected to the distributor spool through a pin shaft.

[0069] The sensor further includes a stroke measurement mechanism. The stroke measurement mechanism is an angle sensor and a linear displacement sensor. The angle sensor is a resistive angle sensor; the linear displacement sensor is a linear potentiometer.

[0070] The stroke measurement mechanism can be directly implemented on the lifting motor, that is, a stepper motor or a servo motor is used as the lifting motor, and the number of rotation turns is calculated in the controller group to obtain the axial movement stroke of the distributor.

[0071] The stroke measurement mechanism either integrates a resolver, or a rotary encoder, or a Hall sensor, or an optical sensor, or a magnetoelectric sensor on the lifting motor to measure the number of revolutions or rotational speed of the motor. After integrating with the working time, the number of revolutions of the motor is obtained, and then the axial movement stroke of the distributor is obtained.

[0072] The stroke measurement mechanism can also be connected to the rotary speed reduction mechanism. A Hall sensor or a magnetoelectric sensor is used to measure the number of teeth of the gear or signal ring passing through the sensor, so as to calculate the number of revolutions of the rotary speed reduction device, and then the axial movement stroke of the distributor is obtained.

[0073] The stroke measurement mechanism can also be connected to the linear reciprocating mechanism, using a grating or a linear potentiometer.

[0074] The stroke measurement mechanism can also use an angle sensor. An angle sensor swing arm is arranged between the linear reciprocating mechanism and the distributor. The effective length of the angle sensor swing arm is greater than 5 mm. The effective length is the distance between the rotation center of the angle sensor and the end of the angle sensor swing arm.

[0075] The angle sensor is arranged between the linear reciprocating mechanism and the distributor through an angle sensor swing arm. The effective length of the angle sensor swing arm is 52 mm, and the effective length is the distance between the rotation center of the angle sensor and the end of the angle sensor swing arm.

[0076] There are also 2 limit position detection mechanisms arranged on the linear reciprocating mechanism, and the limit position detection mechanism is a touch switch.

[0077] The controller cooperates with the stroke measurement mechanism to calibrate the lifting speed of the distributor. Specifically in this embodiment, the lifting motor is driven, and the controller makes the distributor valve core move axially to the required position, and the oil fluid with a specific flow rate flows into or out of the two lifting oil cylinders, so as to push the lifting arm component of the lifter to the target position. The controller group receives the signals of the position sensors, obtains the distance between the current position of the lifter and the target position of the lifter, sets the moving speed of the lifter oil cylinder, and obtains the relationship between the lifting speed and the position of the distributor valve core according to the input signal of the stroke measurement mechanism.

[0078] The lifting rod in this embodiment has a nut and screw structure. The nut is threadedly connected to the screw. The screw end of the lifting rod is connected to the distributor arm through a pin shaft, and the nut end of the lifting rod is connected to the lower pull rod through a pin shaft.

[0079] The maximum displacement S of the hydraulic pump in this embodiment is 45 ml / r, satisfying S > P / 8, where P is the rated maximum total power of the driving machine, and the unit is KW.

Claims

1. A lift for a tractor, the tractor comprising a drive motor that transmits power to the lift to drive implements attached to the lift to different working positions; characterized in that: The lift comprises a hydraulic pump, a distributor, two or more lift cylinders, a lift arm component, two or more lift rods, an upper pull rod, two or more lower pull rods, as well as a lift motor, a rotary reduction mechanism for reducing the output speed of the lift motor, a linear reciprocating mechanism for converting the rotary motion output by the rotary reduction mechanism into a linear motion, a controller group, and a sensor group; the lift motor is connected to the rotary reduction mechanism in a direct or indirect connection manner, the rotary reduction mechanism and the linear reciprocating mechanism are arranged in series, and the linear reciprocating mechanism is connected to the distributor in a direct or indirect connection manner; the hydraulic pump receives the power of the drive motor, the hydraulic pump is provided with a hydraulic pump inlet and a hydraulic pump outlet, the inlet of the hydraulic pump is connected to a hydraulic oil tank through a pipeline, and the outlet is connected to the distributor through a pipeline, and the distributor is connected to two or more lift cylinders through pipelines; The distributor comprises a distributor valve seat, a distributor valve core, and a hydraulic lock. A long through hole is provided in the distributor valve seat. An oil inlet, an oil return port, a lift riser oil port, a lift lowerer oil port, and an oil return cavity connected to the oil return port are provided on the distributor valve seat. The oil inlet, the oil return port, and the oil return cavity are respectively communicated with the long through hole. The oil inlet is connected to the outlet of the hydraulic pump, and the oil return port is connected to an external oil tank through a pipeline. The lift cylinder comprises a first cavity and a second cavity. The lift riser oil port is connected to the first cavities of two or more lift cylinders through pipelines, and the lift lowerer oil port is connected to the second cavities of two or more lift cylinders through pipelines; the distributor valve core is of a rotary body structure, comprising three or more large-diameter sealed large cylindrical surfaces, and small-diameter oil-passing small cylindrical surfaces for oil passage arranged between the large-diameter sealed large cylindrical surfaces; the outer diameter of the sealed large cylindrical surface is D, where D > P / 65, the unit of D is millimeters, and P is the rated maximum total power of the drive motor, with the unit of kilowatts; the diameter of the oil-passing small cylindrical surface is d, where d < D / 1.

1. The distributor valve core is sleeved in the long through hole of the distributor valve seat, and one end of the distributor valve core is connected to the linear reciprocating mechanism in a direct or indirect manner; The displacement or maximum displacement of the hydraulic pump is S, where S > P / 8; the unit of S is ml / r; The total reduction ratio of the rotary reduction mechanism is i1, and the total reduction ratio of the rotary reduction mechanism is the output speed of the lift motor / the output speed of the reduction mechanism; the linear reciprocating mechanism is one or a combination of a screw mechanism, a ball screw mechanism, a sliding screw mechanism, a rack and pinion mechanism, or a link mechanism; the conversion rate of the linear reciprocating mechanism is i2, and the conversion rate of the linear reciprocating mechanism is the ratio between linear motion and rotation, with the unit of mm / r. i1 and i2 satisfy: 0.006 mm / r < < 42 mm / r; A distributor arm is connected to one end of the distributor spool. The linear reciprocating mechanism is connected to the distributor through a push-pull flexible shaft, the distributor arm and the distributor. The diameter of the push-pull flexible shaft is Dsa, where Dsa > P / 100, and the unit of Dsa is mm.

2. The lift for tractor according to claim 1, characterized in that: A spool conical surface with the axis of the distributor spool as the axis of rotation is provided on the distributor spool. The angle between the generatrix of the spool conical surface and the axis of the distributor spool is less than 60° or greater than 120°; The hydraulic lock is of a mechanical hydraulic lock structure, including a push rod, a sealing body, an elastic reset element, a one-way valve core and a one-way valve seat; one end of the valve core conical surface is a conical small cylindrical surface, and the other end of the valve core conical surface is a conical large cylindrical surface. The valve core conical surface can abut against one end of the push rod. The push rod is arranged in the distributor valve seat, and the axis of the push rod is perpendicular to the axis of the distributor valve core; the end of the push rod that does not abut against the valve core conical surface is a small-diameter push rod end, and the diameter of the small-diameter push rod end is smaller than the diameter of the end of the push rod that abuts against the valve core conical surface; an axial through hole is arranged in the one-way valve core, and the axial through hole is a large-diameter through hole and a small-diameter through hole that are interconnected. The connection between the large-diameter through hole and the small-diameter through hole is a through hole step or a through hole transition conical surface. The length of the small-diameter through hole end of the one-way valve core is L1, and the length of the small-diameter push rod end is L2, satisfying L1 - L2 ≤ 2 mm. The end of the small-diameter push rod end abuts against the sealing body arranged in the axial through hole; a sealing surface is arranged between the end of the one-way valve core far from the push rod and the one-way valve seat. The one-way valve seat is sleeved in the lift oil port of the distributor valve seat. The large-end diameter of the sealing surface between the one-way valve core and the one-way valve seat is D1, and the diameter of the small-diameter through hole is D2, satisfying ; one end of the elastic reset element abuts against the sealing body in the axial through hole, and the other end of the elastic reset element is directly or indirectly fixed on the distributor valve seat.

3. The lift for tractor according to claim 1, wherein: The sensor group includes a lift position sensor; the lift position sensor is an angle sensor, the angle sensor includes at least one rotatable measurement rotating shaft, the angle sensor is connected to the lift arm component through at least one angle sensor swing arm mounted on the measurement rotating shaft, the effective length of the angle sensor swing arm is greater than 10 mm, and the effective length is the distance from the rotation center of the measurement rotating shaft of the angle sensor to the end of the angle sensor swing arm; the measurement rotating shaft of the angle sensor is connected to the angle sensor swing arm and rotates together, the angle sensor swing arm is connected to the lift arm component and rotates together, and the measurement range of the angle sensor is at least 10°.

4. The lift for a tractor according to claim 1, characterized in that, One or more pressure buffer ports are arranged at the edge of at least one sealed large cylindrical surface of the distributor spool; the pressure buffer ports form one or more notches at the edge of the sealed large cylindrical surface, and the total arc length of the projection of the one or more notches on the outer circle of the end face of the sealed large cylindrical surface is L, where L > D×P / 8000, and the unit of L is millimeters; the length or height of the pressure buffer port in the axial direction of the distributor spool is greater than 2 mm; the change trend of the cross-sectional area of the pressure buffer port is monotonically changing along the axial direction, and the cross-sectional area of the pressure buffer port is the area of the projection of the pressure buffer port on the planes at different positions perpendicular to the axis of the distributor spool.

5. The lift for a tractor according to claim 1, characterized in that, The sensor group further includes at least one stroke measurement mechanism, the stroke measurement mechanism is connected to the lift motor or the rotary reduction mechanism or the linear reciprocating mechanism, and the stroke measurement mechanism is used to measure the number of revolutions of the motor or the number of revolutions of the gear, or the number of revolutions or the linear stroke of the linear reciprocating mechanism.

6. The lift for a tractor according to claim 5, characterized in that, The stroke measurement mechanism is connected to the linear reciprocating mechanism by a grating or a linear potentiometer.

7. A tractor, characterized in that, The tractor is provided with the lift for tractor according to any one of claims 1 to 6.

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