Compound steering articulated tractor and steering method thereof

Abstract

The invention discloses a compound steering articulated tractor and a steering method thereof, comprising an electronic control system, a front wheel hub, a front axle, a front body, a rear body, a rear axle and a steering mechanism, wherein the front wheel hub is mounted on the front axle, the front axle is connected to the front body, the front body is connected to the rear body via a hinge point, and the steering mechanism connects the rear body, the front body, the front axle and the front wheel hub; the steering mechanism comprises a steering cylinder, a locking straight steering cylinder group and a front wheel steering assembly, a front wheel steering tie rod, a steering rocker arm, an articulated steering tie rod, a follow-up steering rocker arm and a follow-up steering cylinder group connected in sequence; the front wheel steering assembly is connected to the front axle and the front wheel hub, the steering rocker arm is connected to the front body and the steering cylinder, the follow-up steering rocker arm and the follow-up steering cylinder group are connected to the rear body, and the locking straight steering cylinder group is connected to the front body and the rear body; the locking and unlocking of the locking straight steering cylinder group and the follow-up steering cylinder group are controlled by the electronic control system to realize the steering function of locking or unlocking the hinge point.

Description

Technical Field

[0001] The present invention relates to the technical field of tractors, and in particular to a compound steering articulated tractor and a steering method thereof. Background Art

[0002] my country's hilly and mountainous regions are characterized by rugged roads, numerous slopes, and complex road conditions. These areas are primarily located in southern my country, where abundant rainfall makes them suitable for growing crops like rice and rapeseed. To maintain water storage and leveling, rice paddies are often organized into terraces or staggered, hilly plots. The complex geography and diverse rotational cultivation patterns of hilly and mountainous regions make traditional tractors difficult to adapt to. Existing articulated tractors steer by deflecting the hinge point, effectively bending the vehicle body from the center. This has a small turning radius and is widely used for road transportation in hilly and mountainous areas. However, articulated wheel tractors that only deflect the hinge point require large space for turning on the spot and are less suitable for operating in small fields. To address this issue, some existing articulated wheel tractors also deflect the front wheels while deflecting the hinge point, significantly reducing the turning radius and improving steering maneuverability. However, the small turning radius makes these tractors prone to misoperation when used on roads, leading to safety accidents. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to overcome the deficiencies of the prior art and provide a tractor capable of steering the front wheels individually or in combination with the hinge point and the front wheels, and a steering method thereof.

[0004] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0005] A compound steering articulated tractor, comprising an electronic control system, a front wheel hub, a front axle, a front body, a rear body, a rear axle, and a steering mechanism, wherein the front wheel hub is mounted on the front axle, the front axle is connected to the front body, the front body is connected to the rear body via a hinge point, and the steering mechanism connects the rear body, the front body, the front axle, and the front wheel hub;

[0006] The steering mechanism includes a steering cylinder, a locking straight steering cylinder group, a follow-up steering cylinder group, a front wheel steering assembly, and a linkage assembly; the front wheel steering assembly is connected to the front axle and the front wheel hub, the linkage assembly is sequentially connected to the front wheel steering assembly, the front vehicle body, the rear vehicle body, and the follow-up steering cylinder group, the steering cylinder is connected to the linkage assembly, the follow-up steering cylinder group is connected to the rear vehicle body, and the two ends of the locking straight steering cylinder group are respectively connected to the front vehicle body and the rear vehicle body; the locking and unlocking of the locking straight steering cylinder group and the follow-up steering cylinder group are controlled by the electronic control system, and when the steering wheel is turned, the steering cylinder drives the linkage assembly to move forward and backward, and the linkage assembly drives the front wheel steering assembly to complete the left or right turn of the front wheel hub.

[0007] As a further improvement of the above technical solution:

[0008] The electronic control system includes a mechanical control circuit and an electronic control circuit; the mechanical control circuit includes a contactor, a normally closed switch, and an electromagnet A; the electronic control circuit includes a normally open switch, a resistor, a relay, a central control unit, an electromagnet B, an electromagnet C, an electromagnet D, a median value sensor E, and a median value sensor F; and is electrically connected to the lock straight steering cylinder group and the follow-up steering cylinder group through the mechanical control circuit and the electronic control circuit.

[0009] When the mechanical control circuit and the electronic control circuit are opened in sequence within a certain period of time, the locking straight steering cylinder group is unlocked and the follow-up steering cylinder group is locked.

[0010] The lock-straight steering cylinder group includes two two-position two-way solenoid valves, a fuel tank, an oil pipe, and a hydraulic cylinder; the rod chamber and the rodless chamber of the hydraulic cylinder are respectively connected to one end of the two two-position two-way solenoid valves, and the other ends of the two two-position two-way solenoid valves are respectively connected to the fuel tank;

[0011] The electromagnet A is the control electromagnet of the two-position two-way solenoid valve connected to the rod cavity of the hydraulic cylinder in the straight-steering lock cylinder group, the electromagnet B is the control electromagnet of the two-position two-way solenoid valve connected to the rodless cavity of the hydraulic cylinder in the straight-steering lock cylinder group, and the median value sensor E is the median value sensor of the hydraulic cylinder of the straight-steering lock cylinder group.

[0012] The servo steering cylinder group includes two two-position two-way solenoid valves, a replenishing oil tank, an oil pipe, and a hydraulic cylinder; the rod chamber and the rodless chamber of the hydraulic cylinder are respectively connected to one end of the two two-position two-way solenoid valves, and the other ends of the two two-position two-way solenoid valves are respectively connected to the replenishing oil tank;

[0013] The electromagnet C is the control electromagnet of the two-position two-way solenoid valve connected to the rod cavity of the hydraulic cylinder in the servo steering cylinder group, the electromagnet D is the control electromagnet of the two-position two-way solenoid valve connected to the rodless cavity of the hydraulic cylinder in the servo steering cylinder group, and the median value sensor F is the median value sensor of the hydraulic cylinder of the servo steering cylinder group.

[0014] The servo steering cylinder group includes a two-position two-way solenoid valve, a three-way valve, an oil replenishment tank, and a hydraulic cylinder. The rod chamber and the rodless chamber of the hydraulic cylinder are respectively connected to the three-way valve and the oil replenishment tank. The two-position two-way solenoid valve is located between the three-way valve and the oil replenishment tank.

[0015] The front wheel steering assembly includes a right steering knuckle arm, a left steering knuckle arm and a steering tie rod. The right steering knuckle arm and the left steering knuckle arm are connected through the steering tie rod. The right steering knuckle arm and the left steering knuckle arm are respectively connected to the front wheel hub through steering knuckles.

[0016] The linkage assembly includes a front wheel steering rod, a steering rocker arm, an articulated steering rod, and a follow-up steering rocker arm. The steering rocker arm is connected to the front vehicle body, and the follow-up steering rocker arm is connected to the rear vehicle body. The two ends of the front wheel steering rod are respectively connected to the front wheel steering assembly and the steering rocker arm. The two ends of the articulated steering rod are respectively connected to the steering rocker arm and the follow-up steering rocker arm. The follow-up steering cylinder group is connected to the follow-up steering rocker arm.

[0017] When the steering wheel is turned, the steering cylinder drives the front wheel steering rod or steering rocker arm or articulated steering rod or follower steering rocker arm to move forward or backward, thereby driving the front wheel steering assembly to move left or right.

[0018] A steering method for a compound steering articulated tractor, comprising the compound steering articulated tractor described above, including individual front wheel steering and compound steering of the hinge point and the front wheels;

[0019] Individual front wheel steering: Lock the steering cylinder group, operate the steering wheel to turn left or right, the steering cylinder retracts or extends, driving the linkage assembly to rotate forward or backward, the follow-up steering cylinder group extends forward or retracts backward, and the linkage assembly drives the front wheel steering assembly to rotate left or right, realizing the left or right turn of the front wheel hub;

[0020] Compound steering of the hinge point and front wheels: the electronic control system unlocks the lock straight steering cylinder group and locks the follow-up steering cylinder group. When the steering wheel is turned left or right, the steering cylinder retracts or extends, driving the linkage assembly to rotate forward or backward. Since the follow-up steering cylinder group is locked, the lock straight steering cylinder group extends forward or retracts backward, driving the front vehicle body to turn left or right around the hinge point. At the same time, the linkage assembly drives the front wheel steering assembly to move left or right, realizing the front wheel hub and the front vehicle body to turn left or right.

[0021] Includes methods for entering a combined hinge point and front wheel steering mode;

[0022] Turn on the contactor switch to energize electromagnet A and input a lock-on signal to the central control unit. At this time, the oil path between the rod chamber of the lock straight steering oil cylinder group and the oil supply tank is opened, while the oil path between the rodless chamber of the lock straight steering oil cylinder group and the oil supply tank is not opened. The hydraulic cylinder of the lock straight steering oil cylinder group continues to be locked.

[0023] After the central control unit receives the unlocking information, it starts to detect the median value sensor F signal and the start confirmation signal. At the same time, the driver turns on the normally open switch within the specified time. The central control unit determines that the articulated steering is unlocked. At this time, the electromagnet B, electromagnet C, and electromagnet D are all energized, and the oil circuit between the rodless chamber of the lock straight steering cylinder group and the oil tank is also opened. At this time, the hydraulic cylinder of the lock straight steering cylinder group can move freely, and the hydraulic cylinder of the follow-up steering cylinder group is locked in the middle position.

[0024] When the locking steering cylinder group is locked and the articulated steering rod is removed, the steering wheel is turned, and the steering cylinder drives the front wheel steering rod or the steering rocker arm or the follower steering rocker arm to move forward or backward, driving the front wheel steering assembly to move left or right, thereby realizing independent front wheel steering;

[0025] When the locking straight steering cylinder group is unlocked, the articulated steering rod is installed, the follow-up steering cylinder group is locked or the follow-up steering cylinder group is removed to connect the articulated steering rod to the rear vehicle body, the steering wheel is turned, the steering cylinder front wheel steering rod or steering rocker arm or follow-up steering rocker arm moves forward or backward, and at the same time, the locking straight steering cylinder group extends forward or retracts backward, driving the front vehicle body to turn left or right, realizing the compound steering of the hinge point and the front wheels.

[0026] Compared with the prior art, the advantages of the present invention are:

[0027] The present invention relates to a compound steering articulated tractor and a steering method thereof. By locking and unlocking the straight-steering oil cylinder group and the follow-up steering oil cylinder group, the tractor can realize switching between two steering modes: independent front wheel steering and hinge point and front wheel compound steering. In normal road transportation, the independent front wheel steering mode can be applied. At this time, the straight-steering oil cylinder group is locked and the follow-up steering oil cylinder group is unlocked. When the steering wheel is turned, the steering oil cylinder drives the linkage assembly to move forward or backward, drives the follow-up steering oil cylinder group to extend or retract, drives the front wheel steering assembly to move left or right, realizes the front wheel hub to turn left or right, and has a large steering radius to ensure safe driving. When working in small fields, the vehicle can be switched to a combined steering mode of the hinge point and the front wheels. At this time, the lock-straight steering cylinder group is turned on and the follow-up steering cylinder group is locked. When the steering wheel is turned, the steering cylinder drives the linkage assembly forward or backward. Since the follow-up steering cylinder group is locked, the lock-straight steering cylinder group is driven to extend or retract, driving the front vehicle body to turn left or right around the hinge point, and at the same time driving the front wheel steering assembly to move left or right, so that the front wheel hub and the hinge points of the front and rear vehicles can be turned at the same time, resulting in a smaller turning radius and a smaller footprint for turning around in place. It is suitable for working along the edge of small fields with complex borders or turning around, and has better applicability in hilly and mountainous areas, good safety, and convenient operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 The diagram is a schematic diagram of the overall structure of the compound steering articulated tractor of the present invention.

[0029] Figure 2 The invention discloses a schematic diagram showing the principle structure of the steering mechanism of the compound steering articulated tractor.

[0030] Figure 3 The invention discloses a schematic structural diagram of the working principle of the steering cylinder of the compound steering articulated tractor.

[0031] Figure 4 The utility model is a schematic diagram showing the principle structure of the electric control system of the compound steering articulated tractor of the present invention.

[0032] Figure 5 The invention discloses a schematic structural diagram of the individually deflected front wheel steering principle of the compound steering articulated tractor.

[0033] Figure 6 The invention discloses a schematic structural diagram of the compound steering principle of the compound steering articulated tractor.

[0034] The numbers in the figure represent:

[0035] 1. Front wheel hub; 2. Front axle; 3. Front body; 4. Hinge point; 5. Rear body; 6. Rear axle; 7. Steering mechanism; 8. Right steering knuckle arm; 9. Steering tie rod; 10. Left steering knuckle arm; 11. Steering knuckle; 12. Steering cylinder; 13. Front wheel steering rod; 14. Steering rocker arm; 15. Articulated steering rod; 16. Follow-up steering cylinder group; 17. Follow-up steering rocker arm; 18. Straight-lock steering cylinder group; 19. Two-position two-way solenoid valve; 20. Fuel tank; 21. Fuel pipe; 22. Hydraulic cylinder; 23. Median value sensor; 24. Power supply; 25. Normally open switch; 26. Resistor; 27. Relay; 28. Contactor; 29. ​​Normally closed switch; 30. Central control unit; 31. Electronic control system. DETAILED DESCRIPTION

[0036] To facilitate understanding of the present invention, the present invention will be described in more comprehensive and detailed form below in conjunction with the accompanying drawings and preferred embodiments. However, the protection scope of the present invention is not limited to the following specific embodiments.

[0037] Unless otherwise defined, all technical terms used hereinafter have the same meanings as those generally understood by those skilled in the art. The technical terms used herein are only for the purpose of describing specific embodiments and are not intended to limit the scope of protection of the present invention.

[0038] Unless otherwise specified, various raw materials, reagents, instruments and equipment used in the present invention can be purchased from the market or prepared by existing methods.

[0039] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0040] Figures 1 to 5 An embodiment of the compound steering articulated tractor and the steering method thereof of the present invention is shown, which includes an electronic control system 31, a front wheel hub 1, a front axle 2, a front body 3, a rear body 5, a rear axle 6 and a steering mechanism 7. The front wheel hub 1 is mounted on the front axle 2, the front axle 2 is connected to the front body 3, the front body 3 is connected to the rear body 5 via a hinge point 4, and the steering mechanism 7 connects the rear body 5, the front body 3, the front axle 2 and the front wheel hub 1.

[0041] The steering mechanism 7 includes a steering cylinder 12, a locking straight steering cylinder group 18, a follow-up steering cylinder group 16, a front wheel steering assembly and a linkage assembly. The linkage assembly includes a front wheel steering rod 13, a steering rocker arm 14, an articulated steering rod 15, and a follow-up steering rocker arm 17 connected in sequence; the front wheel steering assembly is connected to the front axle 2 and the front wheel hub 1, the steering rocker arm 14 is connected to the front body 3, the follow-up steering rocker arm 17 and the follow-up steering cylinder group 16 are connected to the rear body 5, and the locking straight steering cylinder group 18 is connected to the front body 3 and the rear body 5. When the user turns the steering wheel, the rotating cylinder 12 is extended and retracted to drive the front wheel steering rod 13 or the steering rocker arm 14 or the articulated steering rod 15 or the follow-up steering rocker arm 17 to rotate; the locking straight steering cylinder group 18 and the follow-up steering cylinder group 16 are locked and unlocked through the electronic control system 31 to realize the locking or unlocking of the hinge point steering function, thereby improving the adaptability of the articulated tractor to hilly and mountainous areas.

[0042] In this embodiment, two front wheel hubs 1 are provided, and the front wheel steering assembly includes a right steering knuckle arm 8, a left steering knuckle arm 10 and a steering tie rod 9. The right steering knuckle arm 8 and the left steering knuckle arm 10 are connected by the steering tie rod 9, and the right steering knuckle arm 8 and the left steering knuckle arm 10 are respectively connected to the two front wheel hubs 1 through steering knuckles 11.

[0043] Steering method: including independent front wheel steering and hinge point and front wheel compound steering.

[0044] When the front wheels are turned independently, the lock-straight steering cylinder group 18 is in a locked state. Specifically, the lock-straight steering cylinder group 18 and the follow-up steering cylinder group 16 are respectively arranged on both sides of the rear vehicle body 5. Taking the left turn, the steering cylinder 12 is connected to the steering rocker arm 14 as an example. When the driver turns the steering wheel to turn left, the steering cylinder 12 retracts. Figure 5 As shown, the retraction movement direction is V1, which drives the steering rocker arm 14 to rotate forward. Specifically, at this time, the steering rocker arm 14 is driven to swing clockwise around the installation point of the front body 3, and then the front wheel steering rod 13 is driven to move in the V2 direction, the articulated steering rod 15 is driven to move in the V3 direction, and the hydraulic cylinder 22 in the follow-up steering cylinder group 16 is driven to move in the V4 direction. The front wheel steering rod 13 drives the left steering knuckle arm 10 to rotate, so that the left front wheel hub 1 turns left. At the same time, the left steering knuckle arm 10 drives the steering tie rod 9 to move in the V5 direction, and then drives the right steering knuckle arm 8 to rotate, so that the right front wheel turns left. Since the above-mentioned rod mechanism moves simultaneously, the left and right wheels turn synchronously. At this time, the front wheel hub 1 deflects a degree.

[0045] Since the lock straight steering cylinder group 18 is in a locked state, although the articulated steering rod 15 moves in the V3 direction and the hydraulic cylinder 22 in the follow-up steering cylinder group 16 moves in the V4 direction, the hydraulic cylinder 22 in the follow-up steering cylinder group 16 can freely extend and retract, and the follow-up steering rocker arm 17 can freely rotate around its installation point with the rear body 5, and cannot drive the hinge point 4 to steer. At this time, the tractor can only achieve single front wheel steering. The steering law at this time is the same as the steering law of a car, which is suitable for road transportation and has good safety.

[0046] When turning right, the principle is the same as that of turning left, and the steering is opposite. Specifically: when the driver operates the steering wheel to turn right, the steering cylinder 12 extends, and the retraction direction is the opposite direction of V1, driving the steering rocker arm 14 to rotate backward. Specifically, at this time, the steering rocker arm 14 is driven to swing counterclockwise around the installation point of the front body 3, and then the front wheel steering rod 13 is driven to move in the opposite direction of V2, the articulated steering rod 15 is driven in the opposite direction of V3, and the hydraulic cylinder 22 in the follow-up steering cylinder group 16 is driven in the opposite direction of V4. The front wheel steering rod 13 drives the left steering knuckle arm 10 to rotate, realizing the right turn of the left front wheel hub 1. At the same time, the left steering knuckle arm 10 drives the steering tie rod 9 to move in the opposite direction of V5, and then drives the right steering knuckle arm 8 to rotate, realizing the right turn of the right front wheel. Since the above-mentioned rod mechanism moves simultaneously, the left and right wheels steer synchronously. At this time, the front wheel hub 1 deflects a degree.

[0047] When the tractor is working at a low speed in the field, in order to obtain a smaller turning radius and improve the maneuverability of the tractor, the articulation point and front wheel compound steering mode can be turned on. At this time, the lock straight steering cylinder group 18 is turned on through the electronic control system 31, and the follow-up steering cylinder group 16 is locked. Taking left turn as an example, when the driver turns the steering wheel to turn left, the steering cylinder 12 retracts from the middle position, such as Figure 6 As shown, the retraction direction is V1, which drives the steering rocker arm 14 to swing clockwise around its mounting point on the front body 3. This in turn drives the front wheel steering tie rod 13 in the V2 direction and the articulated steering tie rod 15 in the V3 direction. Because the hydraulic cylinder 22 in the follower steering cylinder group 16 is immobilized, it forms a stable triangle with the rear body 5 and the follower steering rocker arm 17. The front wheel steering tie rod 13 drives the left steering knuckle arm 10 to rotate, causing the front wheel to deflect by a degree. This movement simultaneously drives the articulated steering tie rod 15 in the V3 direction, resulting in a corresponding deflection of β degrees at the hinge point 4. At this point, the front wheel is deflected by γ degrees relative to the centerline of the rear body 5, where γ is equal to the sum of a and β. A and β can be equal or unequal, with the optimal solution being when β is greater than a. The compound steering of the hinge point and the front wheels increases the steering angle, can reduce the turning radius of the tractor, and improve the adaptability to small fields. It is especially suitable for use in hilly and mountainous areas.

[0048] When the tractor turns right in a combined hinge-and-front-wheel steering mode, the driver turns the steering wheel to the right. The steering cylinder 12 then extends from its neutral position in the direction opposite to V1, driving the steering rocker arm 14 to swing counterclockwise around the mounting point on the front body 3. This in turn drives the front-wheel steering tie rod 13 in the direction opposite to V2 and the articulated steering tie rod 15 in the direction opposite to V3. Simultaneously, because the hydraulic cylinder 22 in the slave steering cylinder group 16 is immobilized at its neutral position, it forms a stable triangle with the rear body 5 and the slave steering rocker arm 17. The front wheel steering rod 13 drives the left steering knuckle arm 10 to rotate to the right, so that the front wheel deflection angle is also a degree. The front wheel steering rod 13 drives the left steering knuckle arm 10 while driving the articulated steering rod 15 to move in the opposite direction of V3. The hinge point 4 deflects β degrees accordingly to achieve a right turn. At this time, the front wheel is deflected by γ degrees relative to the central axis of the rear vehicle body 5. γ is equal to the sum of a and β, where a and β can be equal or unequal. The optimal solution is that β is greater than a.

[0049] This compound steering articulated tractor and its steering method, by locking and opening the lock straight steering cylinder group 18 and the follow-up steering cylinder group 16, enables the tractor to realize switching between two steering modes: independent front wheel steering and hinge point and front wheel compound steering. In normal road transportation, the independent front wheel steering mode can be applied. At this time, the lock straight steering cylinder group 18 is locked and the follow-up steering cylinder group 16 is opened. When the steering wheel is turned, the steering cylinder 12 drives the linkage assembly forward or backward, drives the follow-up steering cylinder group 16 to extend or retract, and drives the front wheel steering assembly to move left or right, so that the front wheel hub 1 turns left or right, and the steering radius is large, which can ensure safe driving. During operation, the hinge point and front wheel compound steering mode can be switched. At this time, the lock straight steering cylinder group 18 is turned on and the follow-up steering cylinder group 16 is locked. When the steering wheel is turned, the steering cylinder 12 drives the linkage assembly forward or backward. Since the follow-up steering cylinder group 16 is locked, the lock straight steering cylinder group 18 is driven to extend or retract, driving the front body 3 to turn left or right around the hinge point 4, and at the same time driving the front wheel steering assembly to move left or right, so that the front wheel hub 1 and the hinge point 4 of the front body 3 and the rear body 5 are turned at the same time, the steering radius is smaller, and the U-turn occupies less space. It is suitable for small-scale operations or U-turns in small fields with complex borders, and has better applicability in hilly and mountainous areas, good safety, and convenient operation.

[0050] When the steering cylinder 12 is connected to the front wheel steering rod 13 or the articulated steering rod 15 or the follow-up steering rocker arm 17, the steering principle is similar to that when the steering cylinder 12 is connected to the steering rocker arm 14. The difference is that when the steering wheel is turned, the steering cylinder 12 directly acts on the front wheel steering rod 13 or the articulated steering rod 15 or the follow-up steering rocker arm 17, and then the front wheel steering rod 13 or the articulated steering rod 15 or the follow-up steering rocker arm 17 drives the various structures connected in front to move forward and backward, and finally drives the front wheel steering assembly to achieve steering.

[0051] In this embodiment, the compound steering articulated tractor includes an electronic control system 31, which includes a power supply 24, a mechanical control circuit, and an electronic control circuit. The mechanical control circuit includes a contactor 28, a normally closed switch 29, and an electromagnet A. The electronic control circuit includes a normally open switch 25, a resistor 26, a relay 27, a central control unit 30, electromagnets B, C, D, a median sensor E, and a median sensor F. The electronic control system 31 is electrically connected to the straight-steering cylinder group 18 and the follow-up steering cylinder group 16 via the mechanical and electronic control circuits. When compound steering mode is to be activated, the mechanical control circuit must first be activated, and then the electronic control system must be activated within a certain period of time. Compound steering mode can only be entered when both the mechanical and electronic control circuits are functioning simultaneously. This double insurance prevents the system from being accidentally activated, thereby improving safety.

[0052] The switching principle is as follows:

[0053] Mechanical control circuit: When the switch of contactor 28 is pressed, electromagnet A is energized and a lock-on signal is input to the central control unit 30. The oil circuit between the rod chamber of the straight-wheel steering cylinder group 18 and the oil supply tank 20 is opened. Since the oil circuit between the rodless chamber of the straight-wheel steering cylinder group 18 and the oil supply tank is not opened at this time, the hydraulic cylinder 22 continues to be locked. Therefore, the straight-wheel steering cylinder group 18 continues to play a locking role, and the tractor still mechanically operates in the front-wheel steering mode only.

[0054] Electronic Control Circuit: After receiving the unlock signal, the central control unit (30) begins detecting the signal from the median sensor F and the start confirmation signal. If the median sensor F signal is triggered and the driver presses the normally-open switch (25) within the specified time, the central control unit (30) determines that the articulated steering is unlocked. At this point, electromagnets B, C, and D are all energized, opening the oil circuits between the rodless chamber of the straight-steering cylinder group (18) and the oil supply tank (20). This allows the hydraulic cylinder (22) of the straight-steering cylinder group (18) to move freely, while the hydraulic cylinder (22) of the follow-up steering cylinder group (16) is locked in the neutral position. The system enters the combined steering mode of the hinge point and front wheels. To prevent system misoperation, if the central control unit (30) detects that the start confirmation signal from the electronic control system (31) exceeds a preset value, it will not activate electromagnets (B, C, and D) even if the normally-open switch (25) is pressed while the mechanical control circuit is open. This prevents misoperation and improves driving safety.

[0055] The mechanical control system is in a locked state when the tractor is parked, lacks power or the normally closed switch 29 is pressed, which can ensure that the tractor continues to work after a failure of the compound steering device, thereby improving safety.

[0056] In one embodiment of the present invention, the lock straight steering cylinder group 18 has the same structure as the follow-up steering cylinder group 16, and respectively includes a two-position two-way solenoid valve 19, a replenishing oil tank 20, an oil pipe 21, and a hydraulic cylinder 22; the rod chamber and the rodless chamber of the hydraulic cylinder 22 are respectively connected to one end of the two two-position two-way solenoid valves 19, and the other ends of the two two-position two-way solenoid valves 19 are respectively connected to the replenishing oil tank 20.

[0057] In another embodiment of the present invention, the follow-up steering cylinder assembly 16 includes a 2-position 2-way solenoid valve 19, a tee, a refueling tank 20, and a hydraulic cylinder 22. The rod chamber and rodless chamber of the hydraulic cylinder 22 are connected to the tee and the refueling tank 20, respectively, and the 2-position 2-way solenoid valve 19 is located between the tee and the refueling tank 20. The lock-straight steering cylinder assembly 18 includes a 2-position 2-way solenoid valve 19, a refueling tank 20, an oil pipe 21, and a hydraulic cylinder 22. The rod chamber and rodless chamber of the hydraulic cylinder 22 are connected to one end of the two 2-position 2-way solenoid valves 19, respectively, and the other ends of the two 2-position 2-way solenoid valves 19 are connected to the refueling tank 20.

[0058] Among them, electromagnet A is the control electromagnet of the two-position two-way solenoid valve with rod cavity of the lock straight steering cylinder group 18, electromagnet B is the control electromagnet of the two-position two-way solenoid valve with rodless cavity 19 of the lock straight steering cylinder group 18, and the median value sensor E is the median value sensor 23 of the hydraulic cylinder 22 of the lock straight steering cylinder group 18; electromagnet C is the control electromagnet of the two-position two-way solenoid valve with rod cavity 19 of the follow-up steering cylinder group 16, electromagnet D is the control electromagnet of the two-position two-way solenoid valve with rodless cavity 19 of the follow-up steering cylinder group 16, and the median value sensor F is the median value sensor 23 of the hydraulic cylinder 22 of the follow-up steering cylinder group 16. When the compound steering is turned on, the electronic control system will detect the status of the median value sensor F. The compound steering can only be turned on when the median value sensor F is triggered. At this time, the steering rules of the front and rear wheels maintain a linear relationship. When compound steering is turned off, the electronic control system will detect the status of the median value sensor E. Compound steering can only be turned off when the median value sensor E is triggered. At this time, the center line of the front body 3 and the center line of the rear body 5 pass through the hinge point 4 and coincide with each other.

[0059] When the steering mode is switched to the combined steering of the hinge point and the front wheels, the mechanical control circuit and the electronic control circuit control the electromagnets A, B, C, and D of the two-position two-way solenoid valve 19 to be energized. The hydraulic cylinder 22 of the follow-up steering cylinder group 16 is in the middle position. The two-position two-way solenoid valve 19 of the follow-up steering cylinder group 16 locks the oil in the rod chamber and the rodless chamber of the hydraulic cylinder 22, so that the hydraulic cylinder 22 can neither extend nor retract, and the follow-up steering rocker arm 17 is fixed in a certain position. At this time, the two-position two-way solenoid valve 19 of the locking straight steering cylinder group 18 conducts the oil in the rod chamber and the rodless chamber of the hydraulic cylinder 22. The hydraulic oil can move freely in the rod chamber and the rodless chamber of the hydraulic cylinder 22, the oil pipe 21, and the oil tank 20. The hydraulic cylinder 22 can be extended or retracted accordingly, and the hinge point 4 can be driven to deflect.

[0060] Another embodiment of the present invention: A simple steering solution can be obtained by eliminating the follow-up steering cylinder group 16 and the follow-up steering rocker arm 17. Specifically, when the hydraulic cylinder 22 in the lock-lock steering cylinder group 18 is in the middle position, the articulated steering rod 15 is removed to disconnect the steering rocker arm 14 from the follow-up steering cylinder group 16. The follow-up steering cylinder group 16 can be locked or the follow-up steering cylinder group 16 and the follow-up steering rocker arm 17 can be directly removed. The steering cylinder 12 is connected to the steering rocker arm 14. When the steering wheel is turned, the steering cylinder 12 is extended and retracted to drive the steering rocker arm 14 to rotate, driving the front wheel steering rod 13 to move forward or backward, and driving the front wheel steering assembly to move, thereby realizing independent front wheel steering.

[0061] When the hydraulic cylinder 22 in the straight steering cylinder group 18 is unlocked, the articulated steering rod 15 is installed, the follow-up steering cylinder group 16 is locked or the follow-up steering cylinder group 16 and the follow-up steering rocker arm 17 are directly removed, and the articulated steering rod 15 is connected to the rear body 5, the steering cylinder 12 is connected to the steering rocker arm 14, and the steering wheel is turned. The steering cylinder 12 extends and retracts to drive the steering rocker arm 14 to rotate, and drives the front wheel steering rod 13 to move forward or backward. At the same time, the hydraulic cylinder 22 in the straight steering cylinder group 18 extends and retracts, drives the hinge point 4 to rotate, and drives the front wheel steering assembly to move, realizing the compound steering of the hinge point and the front wheel, simplifying the structure, and achieving the same steering method.

[0062] Another embodiment of the present invention: the steering tie rod 9 is eliminated, and the front wheel steering rod 13 and the steering rocker arm 14 are installed on the right side, or the steering mechanism consisting of the steering rocker arm 14, the articulated steering rod 15 and the follower steering rocker arm 17 is arranged on the other side, or the steering mechanism consisting of the steering rocker arm 14, the articulated steering rod 15 and the follower steering rocker arm 17 is arranged on the same side as the locking steering cylinder group. These structural changes all fall within the scope of protection of this technology.

Claims

1. A compound steering articulated tractor, characterized by: The vehicle comprises an electronic control system (31), a front wheel hub (1), a front axle (2), a front vehicle body (3), a rear vehicle body (5), a rear axle (6), and a steering mechanism (7), wherein the front wheel hub (1) is mounted on the front axle (2), the front axle (2) is connected to the front vehicle body (3), the front vehicle body (3) is connected to the rear vehicle body (5) via a hinge point (4), and the steering mechanism (7) is connected to the rear vehicle body (5), the front vehicle body (3), the front axle (2), and the front wheel hub (1); The steering mechanism (7) comprises a steering cylinder (12), a locking straight steering cylinder group (18), a follow-up steering cylinder group (16), a front wheel steering assembly, and a linkage assembly; the front wheel steering assembly is connected to the front axle (2) and the front wheel hub (1); the linkage assembly is sequentially connected to the front wheel steering assembly, the front vehicle body (3), the rear vehicle body (5), and the follow-up steering cylinder group (16); the steering cylinder (12) is connected to the linkage assembly; the follow-up steering cylinder group (16) is connected to the rear vehicle body (5); and the two ends of the locking straight steering cylinder group (18) are respectively connected to the front vehicle body (3) and the rear vehicle body (5); the locking and unlocking of the locking straight steering cylinder group (18) and the follow-up steering cylinder group (16) are controlled by the electronic control system (31); when the steering wheel is turned, the steering cylinder (12) drives the linkage assembly to move forward and backward, and the linkage assembly drives the front wheel steering assembly to complete the left turn or right turn of the front wheel hub (1); The linkage assembly comprises a front wheel steering rod (13), a steering rocker arm (14), an articulated steering rod (15), and a follower steering rocker arm (17); the steering rocker arm (14) is connected to the front vehicle body (3); the follower steering rocker arm (17) is connected to the rear vehicle body (5); the two ends of the front wheel steering rod (13) are respectively connected to the front wheel steering assembly and the steering rocker arm (14); the two ends of the articulated steering rod (15) are respectively connected to the steering rocker arm (14) and the follower steering rocker arm (17); and the follower steering oil cylinder group (16) is connected to the follower steering rocker arm (17).

2. The compound steering articulated tractor according to claim 1, characterized in that: The electric control system (31) includes a mechanical control circuit and an electronic control circuit; the mechanical control circuit includes a contactor (28), a normally closed switch (29), and an electromagnet A; the electronic control circuit includes a normally open switch (25), a resistor (26), a relay (27), a central control unit (30), an electromagnet B, an electromagnet C, an electromagnet D, a median value sensor E, and a median value sensor F; and is electrically connected to the lock straight steering cylinder group (18) and the follow-up steering cylinder group (16) through the mechanical control circuit and the electronic control circuit.

3. The compound steering articulated tractor according to claim 2, characterized in that: When the mechanical control circuit and the electronic control circuit are opened in sequence within a certain period of time, the locking straight steering cylinder group (18) is unlocked and the follow-up steering cylinder group (16) is locked.

4. The compound steering articulated tractor according to claim 2, characterized in that: The lock straight steering oil cylinder group (18) comprises two two-position two-way solenoid valves (19), an oil supply tank (20), an oil pipe (21), and a hydraulic cylinder (22); the rod chamber and the rodless chamber of the hydraulic cylinder (22) are respectively connected to one end of the two two-position two-way solenoid valves (19), and the other ends of the two two-position two-way solenoid valves (19) are respectively connected to the oil supply tank (20); The electromagnet A is a control electromagnet of a two-position two-way solenoid valve connected to the rod cavity of the hydraulic cylinder (22) in the locking straight steering oil cylinder group (18), the electromagnet B is a control electromagnet of a two-position two-way solenoid valve (19) connected to the rodless cavity of the hydraulic cylinder (22) in the locking straight steering oil cylinder group (18), and the median value sensor E is a median value sensor of the hydraulic cylinder (22) of the locking straight steering oil cylinder group (18).

5. The compound steering articulated tractor according to claim 2, characterized in that: The servo steering cylinder group (16) includes two two-position two-way solenoid valves (19), a replenishing oil tank (20), an oil pipe (21), and a hydraulic cylinder (22); the rod chamber and the rodless chamber of the hydraulic cylinder (22) are respectively connected to one end of the two two-position two-way solenoid valves (19), and the other ends of the two two-position two-way solenoid valves (19) are respectively connected to the replenishing oil tank (20); The electromagnet C is a control electromagnet of a two-position two-way solenoid valve (19) connected to the rod cavity of the hydraulic cylinder (22) in the follow-up steering cylinder group (16); the electromagnet D is a control electromagnet of a two-position two-way solenoid valve (19) connected to the rodless cavity of the hydraulic cylinder (22) in the follow-up steering cylinder group (16); and the median value sensor F is a median value sensor (23) of the hydraulic cylinder (22) of the follow-up steering cylinder group (16).

6. The compound steering articulated tractor according to claim 1, characterized in that: The servo steering cylinder group (16) includes a two-position two-way solenoid valve (19), a three-way connection, an oil replenishment tank (20), and a hydraulic cylinder (22). The rod chamber and the rodless chamber of the hydraulic cylinder (22) are respectively connected to the three-way connection and the oil replenishment tank (20). The two-position two-way solenoid valve (19) is located between the three-way connection and the oil replenishment tank (20).

7. The compound steering articulated tractor according to claim 1, characterized in that: The front wheel steering assembly comprises a right steering knuckle arm (31), a left steering knuckle arm (10) and a steering tie rod (9); the right steering knuckle arm (31) and the left steering knuckle arm (10) are connected via the steering tie rod (9); and the right steering knuckle arm (31) and the left steering knuckle arm (10) are respectively connected to the front wheel hub (1) via steering knuckles.

8. The compound steering articulated tractor according to claim 1, characterized in that: When the steering wheel is turned, the steering cylinder (12) drives the front wheel steering rod (13) or the steering rocker arm (14) or the articulated steering rod (15) or the follower steering rocker arm (17) to move forward or backward, thereby driving the front wheel steering assembly to move left or right.

9. A steering method for a compound steering articulated tractor, comprising the compound steering articulated tractor according to any one of claims 1 to 8, characterized in that: Including independent front wheel steering and combined steering of hinge point and front wheel; Individual front wheel steering: locking the straight steering cylinder group (18), operating the steering wheel to turn left or right, the steering cylinder (12) retracts or extends, driving the linkage assembly to rotate forward or backward, the follower steering cylinder group (16) extends forward or retracts backward, and the linkage assembly drives the front wheel steering assembly to rotate left or right, realizing the front wheel hub (1) to turn left or right; The hinge point and the front wheel are combined in steering: the lock-straight steering cylinder group (18) is unlocked by the electronic control system, and the follow-up steering cylinder group (16) is locked. When the steering wheel is turned left or right, the steering cylinder (12) retracts or extends, driving the linkage assembly to rotate forward or backward. Since the follow-up steering cylinder group (16) is locked, the lock-straight steering cylinder group (18) extends forward or retracts backward, driving the front vehicle body (3) to rotate left or right around the hinge point (4). At the same time, the linkage assembly drives the front wheel steering assembly to move left or right, realizing the front wheel hub (1) and the front vehicle body (3) to rotate left or right.

10. The steering method for a compound steering articulated tractor according to claim 9, characterized in that: Includes methods for entering a combined hinge point and front wheel steering mode; 1) Turn on the switch of the contactor (28) to energize the electromagnet A and input a lock-on signal to the central control unit (30). At this time, the oil circuit between the rod chamber of the lock straight steering oil cylinder group (18) and the oil supply tank (20) is opened, while the oil circuit between the rodless chamber of the lock straight steering oil cylinder group (18) and the oil supply tank (20) is not opened, and the hydraulic cylinder (22) of the lock straight steering oil cylinder group (18) continues to be locked; 2) After the central control unit (30) receives the unlocking information, it starts to detect the median value sensor F signal and the start confirmation signal. At the same time, the driver turns on the normally open switch (25) within the specified time. The central control unit (30) determines that the articulated steering is unlocked. At this time, the electromagnet B, the electromagnet C, and the electromagnet D are all energized, and the oil circuit between the rodless chamber of the lock straight steering cylinder group (18) and the oil tank (20) is also opened. At this time, the hydraulic cylinder (22) of the lock straight steering cylinder group (18) can move freely, and the hydraulic cylinder (22) of the follow-up steering cylinder group (16) is locked in the middle position.

11. The steering method for a compound steering articulated tractor according to claim 10, characterized in that: When the locking straight steering cylinder group (18) is locked and the articulated steering tie rod (15) is disassembled, the steering wheel is turned, and the steering cylinder (12) drives the front wheel steering tie rod (13) or the steering rocker arm (14) or the follower steering rocker arm (17) to move forward or backward, driving the front wheel steering assembly to move left or right, thereby realizing independent front wheel steering; When the locking straight steering cylinder group (18) is unlocked, the articulated steering tie rod (15) is installed, the follow-up steering cylinder group (16) is locked or the follow-up steering cylinder group (16) is removed to connect the articulated steering tie rod (15) to the rear vehicle body, the steering wheel is turned, the steering cylinder (12) front wheel steering tie rod (13) or the steering rocker arm (14) or the follow-up steering rocker arm (17) moves forward or backward, and at the same time, the locking straight steering cylinder group (18) extends forward or retracts backward, driving the front vehicle body (3) to turn left or right, thereby realizing the compound steering of the hinge point and the front wheels.

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