Electric counterbalanced forklift and its electric power steering system

Abstract

The invention discloses an electric counterbalanced forklift and its electric power steering system. The steering system includes a steering wheel assembly, a steering booster connected to the steering wheel assembly, and a steering axle assembly connected to the steering booster through a steering transmission mechanism; the steering booster includes a power-boosting motor, an input shaft, an output shaft, and a torsion bar connected between the input shaft and the output shaft, and the output shaft is connected to the power-boosting motor through a transmission mechanism; the torsion bar is connected to a torque sensor, and the steering booster is connected to a steering angle sensor for detecting the rotation angle of the input shaft. The power-boosting motor, the steering angle sensor, and the torque sensor are all communicatively connected to a steering controller, and the steering controller is used to control the power-boosting motor to cut off power when the steering angle sensor detects that the input shaft rotates to a set limit angle. The steering axle assembly is driven to steer by the power-boosting motor, and electric control steering is used instead of hydraulic control, so that oil leakage can be avoided, environmental protection is achieved, and the operating noise is small.

Description

Technical Field

[0001] The present invention relates to the technical field of forklifts, and in particular to an electric counterbalanced forklift and an electric power steering system thereof. Background Art

[0002] The most widely used steering system in forklifts is the hydraulic power steering system. Due to the characteristics of the hydraulic system, as long as there is a direction signal after the forklift is turned on, the motor will continue to drive the gear pump, which will produce a certain amount of noise, reduce the comfort of operation, and consume a lot of energy; at the same time, due to the change of oil temperature, there will often be oil leakage problems, which will cause pollution to the vehicle and the environment.

[0003] Therefore, how to reduce steering noise and improve environmental protection effect is a technical problem that technicians in this field currently need to solve. Summary of the invention

[0004] In view of this, an object of the present invention is to provide an electric counterbalanced forklift electric power steering system, which can reduce steering noise and improve environmental protection effects. Another object of the present invention is to provide an electric counterbalanced forklift including the above-mentioned electric counterbalanced forklift electric power steering system, which can reduce steering noise and improve environmental protection effects.

[0005] To achieve the above object, the present invention provides the following technical solutions:

[0006] An electric power steering system for an electric counterbalanced forklift, comprising a steering wheel assembly, a steering booster connected to the steering wheel assembly, and a steering axle assembly connected to the steering booster via a steering transmission mechanism; the steering booster comprises a power-boosting motor, an input shaft, an output shaft, and a torsion bar connected between the input shaft and the output shaft, the output shaft being transmission-connected to the power-boosting motor; the torsion bar is connected to a torque sensor, the steering booster is connected to a steering angle sensor for detecting the rotation angle of the input shaft, the power-boosting motor, the steering angle sensor, and the torque sensor are all communicatively connected to a steering controller, the steering controller being used to control the power-boosting motor to be powered off when the steering angle sensor detects that the input shaft has rotated to a set limit angle.

[0007] Preferably, the steering angle sensor is communicatively connected to the travel controller to control the forward speed of the forklift according to the detection result of the steering angle sensor.

[0008] Preferably, the steering booster further includes a housing, the torsion bar is disposed in the housing, the input shaft and the output shaft extend from the housing, and the steering angle sensor is connected to the housing.

[0009] Preferably, the steering transmission mechanism comprises a steering gear transmission assembly connected between the output shaft and the transmission shaft, and a steering chain assembly connected between the transmission shaft and the steering axle assembly.

[0010] Preferably, the steering chain assembly includes a driving sprocket fixed on the transmission shaft, a driven sprocket provided on the steering axle assembly, and a chain drivingly connected to the driving sprocket and the driven sprocket.

[0011] Preferably, the steering gear transmission assembly comprises a driving shaft fixed to the output shaft, a driving gear fixed to the driving shaft, and a driven gear fixed to the transmission shaft, and the driving gear and the driven gear are meshed and matched to transmit power.

[0012] Preferably, the driving shaft and the output shaft are both inserted into a locking sleeve; the locking sleeve comprises a C-shaped sleeve and a locking nut, the C-shaped sleeve is buckled on the output shaft and the driving shaft at the same time, and the locking nut locks the opening of the C-shaped sleeve.

[0013] Preferably, the output end of the steering wheel assembly is connected to a steering column assembly, and the steering column assembly is connected to the steering booster via a universal joint.

[0014] Preferably, a shaft angle sensor is provided on the steering shaft of the steering axle assembly, and the shaft angle sensor is communicatively connected to the steering controller.

[0015] An electric counterbalanced forklift comprises the electric power steering system for the electric counterbalanced forklift as described above.

[0016] The electric power steering system of an electric counterbalanced forklift provided by the present invention comprises a steering wheel assembly, a steering booster connected to the steering wheel assembly, and a steering axle assembly connected to the steering booster through a steering transmission mechanism; the steering booster comprises a power-boosting motor, an input shaft, an output shaft, and a torsion bar connected between the input shaft and the output shaft, and the output shaft is transmission-connected to the power-boosting motor; the torsion bar is connected to a torque sensor, the steering booster is connected to a steering angle sensor for detecting the rotation angle of the input shaft, the power-boosting motor, the steering angle sensor, and the torque sensor are all communicatively connected to a steering controller, and the steering controller is used to control the power-boosting motor to cut off power when the steering angle sensor detects that the input shaft has rotated to a set limit angle.

[0017] The steering of the forklift is realized by the steering booster. When the steering wheel assembly is rotated under force, the torsion bar is driven to twist. The torque sensor detects the twisting of the torsion bar and sends a signal to the steering controller to drive the steering axle assembly to steer through the power-assisted motor. The use of electric control steering instead of hydraulic control can avoid the occurrence of oil leakage problems and has environmental protection effects. The steering control has good followability and sensitivity, and the operating noise is small, which can improve the comfort of the operation. At the same time, the setting of the steering angle sensor can cut off the power supply of the power-assisted motor in time to avoid excessive output force affecting the service life of the steering transmission mechanism.

[0018] The electric counterbalanced forklift provided by the present invention and including the electric power steering system for the electric counterbalanced forklift can reduce steering noise and improve environmental protection effects. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying creative work.

[0020] Figure 1 A structural diagram of the steering system provided by the present invention;

[0021] Figure 2 for Figure 1 A partial enlarged view of the structure.

[0022] Reference numerals:

[0023] Steering wheel assembly 1

[0024] Steering column assembly 2, steering tube 21;

[0025] Universal joint 3;

[0026] Steering booster 4, booster motor 41, input shaft 42, torsion bar 43, output shaft 44, housing 45;

[0027] Locking sleeve 5;

[0028] Steering angle sensor 6;

[0029] Steering gear transmission assembly 7, driven gear 71, transmission shaft 72, driving shaft 73, driving gear 74;

[0030] Steering chain assembly 8, driving sprocket 81, driven sprocket 82, chain 83;

[0031] Steering axle assembly 9, steering axle body 91, wheel hub 92, steering tire assembly 93. DETAILED DESCRIPTION

[0032] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. 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 creative work are within the scope of protection of the present invention.

[0033] The core of the present invention is to provide an electric counterbalanced forklift electric power steering system, which can reduce steering noise and improve environmental protection effects. Another core of the present invention is to provide an electric counterbalanced forklift including the above-mentioned electric counterbalanced forklift electric power steering system, which can reduce steering noise and improve environmental protection effects.

[0034] In a specific embodiment of the electric power steering system for electric counterbalanced forklift provided by the present invention, please refer to Figure 1 and Figure 2 , including a steering wheel assembly 1, a steering booster 4 connected to the steering wheel assembly 1, and a steering axle assembly 9 connected to the steering booster 4 through a steering transmission mechanism.

[0035] The steering booster 4 includes a boost motor 41, an input shaft 42, a torsion bar 43, an output shaft 44, a torque sensor, a steering angle sensor 6, a housing 45 and other parts. The torsion bar 43 is connected between the input shaft 42 and the output shaft 44, and the output shaft 44 is connected to the boost motor 41. The torsion bar 43 is connected to the torque sensor. A worm is connected to the output shaft 44 of the boost motor 41, which meshes with the turbine on the output shaft 44 to drive the output shaft 44. The torque sensor detects the torsion of the torsion bar 43 under the action of the steering wheel assembly, and sends a signal to the steering controller, which controls the boost motor 41 to start, so as to drive the steering axle assembly 9 to steer through the boost motor 41.

[0036] The steering booster 4 is connected to a steering angle sensor 6 for detecting the rotation angle of the input shaft 42. The power-boosting motor 41, the steering angle sensor 6, and the torque sensor are all communicatively connected to the steering controller, and the steering controller is used to control the power-boosting motor 41 to cut off the power when the steering angle sensor 6 detects that the input shaft 42 rotates to a set limit angle. Specifically, the torsion bar 43 is arranged in the housing 45, the input shaft 42 and the output shaft 44 extend from the housing 45, and the steering angle sensor 6 is connected to the housing 45 to detect the rotation of the input shaft 42. More specifically, the steering angle sensor 6 is a photosensitive element. Of course, in other embodiments, the steering angle sensor 6 can also be an encoder fixed on the input shaft 42.

[0037] Among them, two setting limit angles can be specifically set, which can correspond to the clockwise rotation limit position and the counterclockwise rotation limit position of the steering wheel assembly 1 respectively. When the steering angle sensor 6 detects that the input shaft 42 rotates to the corresponding setting limit angle along with the steering wheel assembly 1, the power-assisting motor 41 is controlled to be powered off to prevent the steering axle assembly 9 from over-rotating. When the input shaft 42 is at an angle other than the setting limit angle, the steering controller can start the power-assisting motor 41 according to the signal of the torque sensor. In addition, the setting limit angle is not limited to being set to two, and in other embodiments, it can also be various angle values ​​within a continuous rotation angle range.

[0038] In this embodiment, a steering booster 4 is used to achieve the steering of the forklift. When the steering wheel assembly 1 is rotated under force, the torsion bar 43 is driven to twist. The torsion sensor detects the twisting of the torsion bar 43 and sends a signal to the steering controller to drive the steering axle assembly 9 to steer through the power-assisted motor 41. The use of electric control steering instead of hydraulic control can avoid the occurrence of oil leakage problems, has an environmental protection effect, and has good followability and sensitivity of the steering control, and has low operating noise, which can improve the comfort of the operation. At the same time, the setting of the steering angle sensor 6 can cut off the power supply of the power-assisted motor 41 in time to avoid excessive output force affecting the service life of the steering transmission mechanism.

[0039] Furthermore, the steering angle sensor 6 is communicatively connected to the travel controller to control the forward speed of the forklift according to the detection result of the steering angle sensor. The steering angle sensor 6 feeds back the position of the steering axle assembly 9, and the travel controller controls the speed of the travel motor, thereby controlling the relationship between the turning angle and the speed, so that the forklift can be controlled to reduce the speed when turning based on its signal, thereby improving the turning stability.

[0040] Furthermore, the steering transmission mechanism includes a steering gear transmission assembly 7 connected between the output shaft 44 and the transmission shaft 72 and a steering chain assembly 8 connected between the transmission shaft 72 and the steering axle assembly 9. Since the steering axle assembly 9 of the electric counterbalanced forklift is on the rear axle and the steering wheel assembly 1 is in the front, as shown in FIG. Figure 1 As shown, a long distance mechanical connection is required from the steering booster 4 to the steering axle assembly 9, and the mechanical connection is realized by a set of gear transmission and a set of chain transmission, which is convenient for assembly.

[0041] Furthermore, the steering chain assembly 8 includes a driving sprocket 81 fixed on the transmission shaft 72, a driven sprocket 82 arranged on the steering axle assembly 9, and a chain 83 that is transmission-connected to the driving sprocket 81 and the driven sprocket 82. Specifically, the driving sprocket 81 is a small sprocket, and the driven sprocket 82 is a large sprocket. In addition, a locking nut can be provided on the chain 83 to adjust the tightness of the chain 83. Among them, the steering axle assembly 9 includes a steering shaft, a steering axle body 91, a wheel hub 92, a steering tire assembly 93, bearings, end caps and other parts, and the steering shaft of the steering axle assembly 9 is connected to the internal spline in the driven sprocket 82. The transmission shaft 72 on the front side of the forklift and the steering axle assembly 9 on the rear side of the forklift are connected by the chain 83. During the maintenance process, the front and rear structures can be separated by loosening the chain 83, which is convenient for disassembly.

[0042] Furthermore, the steering gear transmission assembly 7 includes a driving shaft 73 fixed to the output shaft 44, a driving gear 74 fixed to the driving shaft 73, and a driven gear 71 fixed to the transmission shaft 72, and the driving gear 74 and the driven gear 71 are meshed and matched to transmit. Specifically, the driving shaft 73 and the transmission shaft 72 are fixed to the bracket, the driving gear 74 is a small gear, and the driven gear 71 is a large gear. The shaft and the gears thereon can be connected by a key to rotate synchronously. The gear transmission has high transmission accuracy and occupies less space.

[0043] Furthermore, the driving shaft 73 and the output shaft 44 are both inserted into the locking sleeve 5. Specifically, the locking sleeve 5 includes a C-shaped sleeve and a locking nut, the C-shaped sleeve is buckled on the output shaft 44 and the driving shaft 73 at the same time, and the locking nut locks the opening of the C-shaped sleeve, the connection flexibility is high, the driving shaft 73 and the output shaft 44 can be adaptively locked in combination with the size of the shaft, and it is easy to disassemble.

[0044] Further, the output end of the steering wheel assembly 1 is connected to the steering column assembly 2, and the steering column assembly 2 is connected to the steering booster 4 through the universal joint 3. Optionally, the steering column assembly 2 includes a steering tube 21, a steering shaft 22, a bearing, a retaining ring and other components, and the universal joint 3 includes three parts: an upper end component, a middle end component and a lower end component. Among them, the steering tube 21 is fixed on the frame, the upper end of the steering shaft 22 of the steering column assembly 2 is connected to the steering wheel assembly 1, the lower end of the steering shaft 22 of the steering column assembly 2 is connected to the upper end component of the universal joint 3, and the lower end component of the universal joint 3 is connected to the input shaft 42 of the steering booster 4.

[0045] Furthermore, an axle angle sensor is provided on the steering shaft of the steering axle assembly 9, and the axle angle sensor is communicatively connected to the steering controller, and the steering controller can compare the detection values ​​of the axle angle sensor and the steering angle sensor 6 to detect the steering effect. In addition, when the steering angle sensor 6 is damaged, the steering controller can also control the power-off of the power-assist motor 41 according to the angle detection of the axle angle sensor.

[0046] The working principle of the electric power steering system of the electric counterbalanced forklift provided in this embodiment is as follows: the steering wheel assembly 1 is turned, and the power is transmitted to the steering booster 4 through the steering column and the universal joint 3. The torsion bar 43 in the steering booster 4 is forced to move and send a signal to the torque sensor. The torque sensor sends a signal to the steering controller, and the steering controller sends a command to let the power motor 41 output the speed, direction and torque. At the same time, the steering angle sensor 6 sends a signal to the travel controller, and the travel controller sends a command to let the travel motor output the speed to realize the turning speed reduction function. The steering booster 4 drives the steering axle assembly 9 to rotate through gear transmission and chain transmission to realize the turning of the steering axle and realize the electric power steering.

[0047] The steering system can reduce energy consumption, extend single operation time and improve work efficiency; the steering is easy to use, which reduces the workload of operators; it is connected through mechanical components, has good followability, precise control and direct road feel; the whole vehicle has low noise, is energy-saving and environmentally friendly, and provides a comfortable working environment for operators.

[0048] In addition to the above-mentioned electric counterbalanced forklift electric power steering system, the present invention also provides an electric counterbalanced forklift, which includes an electric counterbalanced forklift electric power steering system, which can be the electric counterbalanced forklift electric power steering system provided in any of the above embodiments, and the beneficial effects can be referred to the above embodiments accordingly. The structures of other parts of the electric counterbalanced forklift can refer to the prior art, which will not be described in detail herein.

[0049] It should be noted that when an element is referred to as "fixing" another element, it can be directly on the other element or there can also be a centered element. When an element is considered to be "connected" to another element, it can be directly connected to the other element or there can be a centered element at the same time. The orientation or position relationship indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inside", "outside", etc. is based on the orientation or position relationship shown in the accompanying drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance.

[0050] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used in the specification of the present invention herein are only for the purpose of describing specific embodiments and are not intended to limit the present invention.

[0051] The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other.

[0052] The above is a detailed introduction to the electric counterbalanced forklift and the electric power steering system for the electric counterbalanced forklift provided by the present invention. This article uses specific examples to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only used to help understand the method of the present invention and its core idea. It should be pointed out that for ordinary technicians in this technical field, without departing from the principle of the present invention, the present invention can also be improved and modified in a number of ways, and these improvements and modifications also fall within the scope of protection of the claims of the present invention.

Claims

1. An electric power steering system for an electric counterbalanced forklift. It is characterized in that The invention comprises a steering wheel assembly (1), a steering booster (4) connected to the steering wheel assembly (1), and a steering axle assembly (9) connected to the steering booster (4) via a steering transmission mechanism; the steering booster (4) comprises a booster motor (41), an input shaft (42), an output shaft (44), and a torsion bar (43) connected between the input shaft (42) and the output shaft (44); the output shaft (44) is transmission-connected to the booster motor (41); the torsion bar (43) is connected to a torque sensor; the steering booster (41) is connected to a steering wheel assembly (1), and a steering axle assembly (9) connected to the steering booster (41) via a steering transmission mechanism; the steering booster (41) comprises a booster motor (41), an input shaft (42), an output shaft (44), and a torsion bar (43) connected between the input shaft (42) and the output shaft (44); the output shaft (44) is transmission-connected to the booster motor (41); the torsion bar (43) is connected to a torque sensor; ) is connected to a steering angle sensor (6) for detecting the rotation angle of the input shaft (42); the power-assisting motor (41), the steering angle sensor (6), and the torque sensor are all communicatively connected to a steering controller; the steering controller is used to control the power-assisting motor (41) to cut off power when the steering angle sensor (6) detects that the input shaft (42) has rotated to a set limit angle; the steering angle sensor (6) is communicatively connected to a travel controller to control the forward speed of the forklift according to the detection result of the steering angle sensor (6); The steering transmission mechanism comprises a steering gear transmission assembly (7) connected between the output shaft (44) and the transmission shaft (72) and a steering chain assembly (8) connected between the transmission shaft (72) and the steering axle assembly (9); the steering gear transmission assembly (7) comprises a driving shaft (73) fixed to the output shaft (44), a driving gear (74) fixed to the driving shaft (73) and a driven gear (71) fixed to the transmission shaft (72); the driving gear (74) and the driven gear (71) are meshed and matched to transmit; the driving shaft (73) and the output shaft (44) are both inserted into a locking sleeve (5); the locking sleeve (5) comprises a C-shaped sleeve and a locking nut; the C-shaped sleeve is buckled to the output shaft (44) and the driving shaft (73) at the same time; the locking nut locks the opening of the C-shaped sleeve; When the steering wheel assembly (1) is rotated, power is transmitted to the steering booster (4), the torsion bar (43) in the steering booster (4) is forced to move and sends a signal to the torque sensor, the torque sensor sends a signal to the steering controller, and the steering controller sends a command to the power-assisted motor (41) to output a rotation speed, direction and torque; at the same time, the steering angle sensor (6) sends a signal to the travel controller, and the travel controller sends a command to the travel motor to output a rotation speed to achieve a turning speed reduction function; the steering booster (4) drives the steering axle assembly (9) to rotate through gear transmission and chain transmission, so as to achieve turning of the steering axle and realize electric power steering.

2. The electric power steering system for electric counterbalanced forklift according to claim 1, It is characterized in that The steering booster (4) further comprises a housing (45), the torsion bar (43) is arranged in the housing (45), the input shaft (42) and the output shaft (44) extend from the housing (45), and the steering angle sensor (6) is connected to the housing (45).

3. The electric power steering system for an electric counterbalanced forklift according to claim 1, It is characterized in that The steering chain assembly (8) comprises a driving sprocket (81) fixed on the transmission shaft (72), a driven sprocket (82) provided on the steering axle assembly (9), and a chain (83) drivingly connected to the driving sprocket (81) and the driven sprocket (82).

4. The electric power steering system for an electric counterbalanced forklift according to claim 1, It is characterized in that The output end of the steering wheel assembly (1) is connected to the steering column assembly (2), and the steering column assembly (2) is connected to the steering booster (4) via a universal joint (3).

5. The electric power steering system for an electric counterbalanced forklift according to claim 1, It is characterized in that A shaft angle sensor is provided on the steering shaft of the steering axle assembly (9), and the shaft angle sensor is communicatively connected to the steering controller.

6. An electric counterbalanced forklift, It is characterized in that The invention comprises an electric power steering system for an electric counterbalanced forklift according to any one of claims 1 to 5.

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