Steering system for forklift and steering control method

Abstract

The steering system comprises a steering control mechanism and a connecting support, the steering control mechanism is connected with the upper end of the connecting support, and the lower end of the connecting support is connected with a steering sensor through a rotary supporting bearing. The outer side of the supporting pivotal bearing is connected with a mounting base used for supporting the supporting pivotal bearing, the steering sensor is a variable damping sensor, and the method comprises the following steps that 1, a forklift driving speed signal is obtained; step 2, calculating an input current signal of a steering sensor; step 3, generating rotation damping; 4, the driver rotates a steering control mechanism; and 5, the steering wheels are controlled to rotate through the rotating angle of the steering sensor, and forklift steering is completed. According to the forklift steering control method, the steering sensor with the variable damping is arranged, the forklift speed of the forklift is associated with the steering hand control force of a driver on a steering system, and the steering control force of the forklift is changed along with the change of the running speed of the forklift.

Description

Technical Field

[0001] The present invention relates to the technical field of forklift steering systems, and in particular to a forklift steering system and a steering control method. Background Art

[0002] The steering system is a critical component of forklifts. As industrial vehicles, forklifts currently rely on hydraulic steering, relying on a gear pump to drive hydraulic oil as the medium. When the steering wheel or joystick turns left or right, the mechanical structure activates the switching of the steering gear's left and right oil circuits, thereby achieving left and right steering of the forklift. While this steering control method can meet the forklift's steering control requirements, its constant steering force leads to operational discomfort caused by the high driver hand force required to steer the forklift in place. Furthermore, when the forklift is traveling at high speeds, the driver's hand force is insufficient, leading to the driver unconsciously turning the steering wheel or joystick quickly, potentially causing a rollover safety hazard. Summary of the Invention

[0003] An object of the present invention is to provide a steering system and a steering control method for a forklift to solve the problems raised in the above background technology.

[0004] To achieve the above object, the present invention provides the following technical solutions:

[0005] A steering system for a forklift includes a steering control mechanism and a connecting support. The steering control mechanism is connected to the upper end of the connecting support. The lower end of the connecting support is connected to a steering sensor via a slewing support bearing. The outer side of the supporting slewing bearing is connected to a mounting base for supporting the supporting slewing bearing. The steering sensor is a variable damping sensor.

[0006] As a further solution of the present invention: the steering control mechanism includes a steering support fixedly connected to the upper end of the connecting support, the steering support is rotatably connected to a connecting rod, the end of the connecting rod away from the steering support is fixedly connected to a steering tiller, and the rotation axis of the connecting rod on the steering support is arranged perpendicular to the axis of the connecting support.

[0007] As a further solution of the present invention: a gas spring for resetting the connecting rod is provided between the connecting rod and the steering support.

[0008] As a further solution of the present invention: the connecting support includes a support body, the support body is a cylindrical structure with an open upper end, the support body is provided with a first connecting hole fixedly connected to the steering support, and the lower end of the support body is provided with a second connecting hole fixedly connected to the slewing support bearing.

[0009] As a further solution of the present invention: the slewing support bearing includes a bearing inner ring and a bearing outer ring that are rotatably connected, and the bearing inner ring and the bearing outer ring are both provided with bearing connection holes. The mounting base includes a mounting plate, and the mounting plate is provided with a third connection hole and a fourth connection hole. The mounting base is fixedly connected to the bearing connection hole on the bearing outer ring through the fourth connection hole.

[0010] As a further solution of the present invention: the mounting base includes a mounting plate, a limit block mounting groove is provided on the mounting plate, a limit block is fixedly connected in the limit block mounting groove, the limit block is located on the outside of the connecting support, and the outer wall of the connecting support is provided with a limit block that cooperates with the limit block.

[0011] A forklift steering system control method comprises the following steps:

[0012] Step 1: Obtain the forklift driving speed signal;

[0013] Step 2: Calculate the steering sensor input current signal based on the forklift's speed signal. The faster the vehicle speed, the stronger the steering sensor input current signal.

[0014] Step 3: The steering sensor generates rotation damping according to the input current signal. The stronger the steering sensor input current signal, the greater the steering sensor rotation damping generated.

[0015] Step 4: The driver rotates the steering mechanism, and the steering mechanism overcomes the damping generated by the steering sensor in step 3, driving the steering sensor to rotate;

[0016] Step 5: Control the steering wheel rotation through the rotation angle of the steering sensor to complete the forklift steering.

[0017] As a further solution of the present invention: in step 1, the speed of the forklift is obtained by setting a speed sensor on the wheel side.

[0018] As a further solution of the present invention: the forklift speed V and the input current I of the steering sensor satisfy I=a*V+c.

[0019] As a further solution of the present invention: the input current I of the steering sensor and the output torque T of the steering sensor generating damping satisfy T=b*I+d.

[0020] Compared with the prior art, the beneficial effect of the present invention is as follows: the present application associates the vehicle speed of the forklift with the driver's steering hand control force on the steering system by setting a steering sensor with variable damping, so that the magnitude of the vehicle's steering control force changes with the vehicle's running speed. That is, the faster the vehicle speed, the greater the steering damping, and the greater the force required to overcome the damping of the steering sensor to achieve steering, thereby greatly avoiding the risk of the forklift overturning due to rapid steering at a high speed. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 This is a schematic diagram of the steering system structure of this embodiment;

[0022] Figure 2 This is a cross-sectional view of the steering system of this embodiment;

[0023] Figure 3 、 Figure 4 This is a schematic diagram of the connecting support structure of this embodiment;

[0024] Figure 5 This is a schematic diagram of the slewing support bearing structure of this embodiment;

[0025] Figure 6 This is a structural view of the limit block of this embodiment;

[0026] Figure 7 This is a schematic diagram of the mounting base structure of this embodiment;

[0027] Figure 8 、 Figure 9 This is a schematic diagram of the steering sensor structure of this embodiment;

[0028] Figure 10 This is a schematic diagram of the steering system flow in this embodiment;

[0029] Figure 11 This is a schematic diagram of the output current corresponding to the vehicle speed in this embodiment;

[0030] Figure 12 This is a schematic diagram of the output current corresponding to the output torque in this embodiment;

[0031] In the figure: 1-steering control mechanism, 11-steering tiller, 12-connecting rod, 13-gas spring, 14 steering support, 2-connecting support, 21-support body, 22-first connecting hole, 23-second connecting hole, 24-limit block, 3-slewing support bearing, 31-bearing outer ring, 32-bearing inner ring, 33-bearing connecting hole, 4-limit block, 5-mounting base, 51-mounting plate, 52-third connecting hole, 53-limit block mounting groove, 54-fourth connecting hole, 6-steering sensor, 61-housing, 62-coil, 63-rotor, 64-Hall sensor, 65-magnet, 66-magnetic fluid. DETAILED DESCRIPTION

[0032] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0033] See also Figure 1 In an embodiment of the present invention, a steering system for a forklift includes a steering control mechanism 1, a connecting support 2, a slewing support bearing 3, a limit block 4, a mounting base 5, and a steering sensor 6.

[0034] See also Figure 2 The steering mechanism 1 is connected to the upper end of the connecting support 2. The steering mechanism 1 includes a steering support 14 fixedly connected to the upper end of the connecting support 2. The steering support 14 is rotatably connected to a connecting rod 12. The end of the connecting rod 12 away from the steering support 14 is fixedly connected to a steering tiller 11. The rotation axis of the connecting rod 12 on the steering support 14 is arranged perpendicular to the axis of the connecting support 2. A gas spring 13 is provided between the connecting rod 12 and the steering support 14 for resetting the connecting rod 12.

[0035] See also Figure 3 、 Figure 4 The connecting support 2 includes a support body 21, which is a cylindrical structure with an open upper end. The support body 21 is provided with a first connecting hole 22 fixedly connected to the steering support 14, and the lower end of the support body 21 is provided with a second connecting hole 23 fixedly connected to the slewing support bearing. A limit stopper 24 is provided on the outer wall of the support body 21.

[0036] See also Figure 5 、 Figure 6 、 Figure 7The lower end of the connecting support 2 is connected to a steering sensor 6 through a slewing support bearing 3, and a mounting base 5 for supporting the slewing bearing 3 is connected to the outside of the supporting slewing bearing 3. The slewing support bearing 3 includes a bearing inner ring 31 and a bearing outer ring 32 that are rotatably connected. The bearing inner ring 31 and the bearing outer ring 32 are both provided with bearing connecting holes 33. The mounting base 5 includes a mounting plate 51, and a third connecting hole 52 and a fourth connecting hole 54 are provided on the mounting plate 51. The mounting plate 51 is fixedly connected to the vehicle frame through the third connecting hole 52, and the mounting base 5 is fixedly connected to the bearing connecting hole 33 on the bearing outer ring 32 through the fourth connecting hole 54. The mounting base 5 includes a mounting plate 51, and a limit block mounting groove 53 is provided on the mounting plate 51. The limit block 4 is fixedly connected to the limit block mounting groove 53. The limit block 4 is located on the outside of the connecting support 2 and cooperates with the limit stopper 24 on the outer wall of the connecting support 2, thereby limiting the rotation of the connecting support 2 on the outside to prevent excessive rotation.

[0037] See also Figure 8 、 Figure 9 The steering sensor 6 is a variable damping sensor. It includes a housing 61, a rotor 63, and a coil 62 disposed within the housing 1. A magnetic fluid 66 is disposed between the coil 62 and the rotor 63. A Hall sensor 64 and a magnet 65 are disposed at the end of the rotor 63. Rotating the steering sensor generates a rotation angle parameter, which is then used to calculate the steering angle of the steering wheel. This angle is then controlled to rotate the steering wheel accordingly. On the one hand, the built-in non-contact Hall sensor can detect and transmit the real-time position of the rotor, inputting a steering position signal to the steering electronic control, further controlling the steering motor and achieving steering control. On the other hand, a steering damping function is integrated, utilizing the corresponding relationship between the viscosity of the magnetorheological fluid material and the magnetic field to achieve steering damping control.

[0038] The strength of the electromagnetic field is controlled by controlling the input current, which is used to measure the steering angle input to the controller and provide steering torque feedback to the driver.

[0039] See also Figure 10-12 , a forklift steering system control method, comprising the following steps:

[0040] Step 1: Obtain the forklift's speed signal by setting a speed sensor on the wheel side to obtain the forklift's speed;

[0041] Step 2: Calculate the steering sensor input current signal based on the forklift speed signal. The forklift speed V and the steering sensor input current I satisfy I = a*V + c.

[0042] Step 3: The steering sensor generates rotational damping based on the input current signal. The input current I of the steering sensor and the output torque T of the steering sensor generate the damping satisfy T = b * I + d. According to the electromagnetic and magnetorheological fluid material properties, different current inputs correspond to different electromagnetic fields. Different electromagnetic fields are converted into different viscosities of the magnetorheological fluid material, thereby achieving different steering forces operated by the driver's hand.

[0043] Step 4: The driver rotates the steering mechanism, and the steering mechanism overcomes the damping generated by the steering sensor in step 3, driving the steering sensor to rotate;

[0044] Step 5: Control the steering wheel rotation through the rotation angle of the steering sensor to complete the forklift steering.

[0045] Example 1

[0046] This embodiment utilizes this steering control system on a folding platform stacker truck. By collecting the forklift's speed signal and converting it into an electric current, this current is fed into a steering sensor. The sensor's internal coil then converts the current into a corresponding magnetic field. This magnetic field causes the magnetorheological fluid to produce varying viscosities, resulting in different damping values ​​for the sensor's rotating shaft during rotation. This achieves varying steering forces for the driver. This vehicle achieves a steering force of 8N at a speed of 12km / h and 3N at a speed of 5km / h.

[0047] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above and that the invention can be embodied in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered in all respects as illustrative and non-restrictive, and the scope of the invention is defined by the appended claims, not the foregoing description, and all variations within the meaning and range of equivalents of the claims are intended to be included therein. Any reference sign in a claim should not be construed as limiting the claim to which it relates.

[0048] In addition, it should be understood that although this specification is described in terms of implementation methods, not every implementation method contains only one independent technical solution. This narrative method of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other implementation methods that can be understood by those skilled in the art.

Claims

1. A forklift steering system, characterized in that: The invention comprises a steering mechanism (1) and a connecting support (2), wherein the steering mechanism (1) is connected to the upper end of the connecting support (2), the lower end of the connecting support (2) is connected to a steering sensor (6) via a slewing support bearing (3), the outer side of the supporting slewing bearing (3) is connected to a mounting base (5) for supporting the supporting slewing bearing (3), and the steering sensor (6) is a variable damping sensor.

2. A forklift steering system according to claim 1, characterized in that: The steering control mechanism (1) comprises a steering support (14) fixedly connected to the upper end of the connecting support (2); the steering support (14) is rotatably connected to a connecting rod (12); one end of the connecting rod (12) away from the steering support (14) is fixedly connected to a steering tiller (11); and the rotation axis of the connecting rod (12) on the steering support (14) is arranged perpendicular to the axis of the connecting support (2).

3. A forklift steering system according to claim 2, characterized in that: A gas spring (13) for resetting the connecting rod (12) is provided between the connecting rod (12) and the steering support (14).

4. The forklift steering system according to claim 2, characterized in that: The connecting support (2) includes a support body (21), the support body (21) is a cylindrical structure with an upper end open, a first connecting hole (22) fixedly connected to the steering support (14) is provided on the support body (21), and a second connecting hole (23) fixedly connected to the slewing support bearing is provided at the lower end of the support body (21).

5. The forklift steering system according to claim 1, characterized in that: The slewing support bearing (3) includes a bearing inner ring (31) and a bearing outer ring (32) that are rotatably connected. The bearing inner ring (31) and the bearing outer ring (32) are both provided with a bearing connection hole (33). The mounting base (5) includes a mounting plate (51). The mounting plate (51) is provided with a third connection hole (52) and a fourth connection hole (54). The mounting base (5) is fixedly connected to the bearing connection hole (33) on the bearing outer ring (32) through the fourth connection hole (54).

6. The forklift steering system according to claim 1, characterized in that: The mounting base (5) comprises a mounting plate (51), a limit block mounting groove (53) is provided on the mounting plate (51), a limit block (4) is fixedly connected in the limit block mounting groove (53), the limit block (4) is located outside the connecting support (2), and a limit block (24) cooperating with the limit block (4) is provided on the outer wall of the connecting support (2).

7. A forklift steering system control method using the forklift steering system according to any one of claims 1 to 6, characterized in that: The following steps are involved: Step 1: Obtain the forklift driving speed signal; Step 2: Calculate the steering sensor input current signal based on the forklift's speed signal. The faster the vehicle speed, the stronger the steering sensor input current signal. Step 3: The steering sensor generates rotation damping according to the input current signal. The stronger the steering sensor input current signal, the greater the steering sensor rotation damping generated. Step 4: The driver rotates the steering mechanism, and the steering mechanism overcomes the damping generated by the steering sensor in step 3, driving the steering sensor to rotate; Step 5: Control the steering wheel rotation through the rotation angle of the steering sensor to complete the forklift steering.

8. The forklift steering system control method according to claim 7, characterized in that: In step 1, the speed of the forklift is obtained by setting a speed sensor on the wheel side.

9. The forklift steering system control method according to claim 7, characterized in that: The forklift speed V and the input current I of the steering sensor satisfy I=a*V+c.

10. The forklift steering system control method according to claim 7, characterized in that: The input current I of the steering sensor and the damped output torque T of the steering sensor satisfy T=b*I+d.

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