Electric steering axle structure of forklift
By employing a permanent magnet synchronous motor and high-precision sensors in the forklift steering axle, combined with the CAN communication protocol, the problems of insufficient precision, slow response speed, and high maintenance cost of traditional forklift steering axles are solved, achieving high-precision, fast-response, and low-maintenance steering performance.
Patent Information
- Application Number
- CN202610024193.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-01-09
- Publication Date
- 2026-03-06
AI Technical Summary
Traditional forklift steering axles suffer from insufficient steering precision, slow response speed, high maintenance costs, and poor installation compatibility, failing to meet the high precision, fast response, and maintenance-free requirements of intelligent warehousing.
It adopts a permanent magnet synchronous motor and high-precision sensor design, combined with CAN communication protocol, to achieve high-precision control and fast response. The rotary motion is converted into linear motion by a three-phase permanent magnet motor driving a lead screw. The internal angle sensor of the motor accurately controls the position, and the IP67 sealing design is adopted to protect against harsh environments.
It achieves high-precision control of forklift steering, with a response time of less than 2.4 seconds, a rated speed of 30 mm/sec, a peak speed of 60 mm/sec, and a maximum continuous thrust of 38 Kn, reducing maintenance costs and improving system stability and installation compatibility.
Smart Images
Figure CN121609267A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of forklift technology, specifically to an electric steering axle structure for forklifts. Background Technology
[0002] In the logistics and warehousing sector, 3-3.5t forklifts are the mainstream material handling equipment, and the performance of their steering axle systems directly affects operational efficiency and safety. Traditional forklift steering axles mostly employ a mechanical-hydraulic drive structure, which suffers from the following technical bottlenecks:
[0003] Insufficient steering precision: The hydraulic system is affected by the viscosity and pressure fluctuations of the oil, and the position control precision is usually above ±0.5mm, which is difficult to meet the high-precision warehousing requirements when the shelf spacing is reduced to 1.2m.
[0004] Lagging response speed: The hydraulic servo system takes more than 4 seconds to complete a ±70mm stroke from receiving a steering command, which cannot meet the requirements of high-frequency, short-distance steering operations in e-commerce warehousing.
[0005] High maintenance costs: The hydraulic system requires regular hydraulic oil replacement (replacement cycle is about 500 hours) and there is a risk of oil leakage. According to statistics, the annual maintenance cost of traditional steering axles accounts for more than 35% of the total maintenance cost of forklifts.
[0006] Poor installation compatibility: Traditional electric push rod retrofits require adjustments to the forklift counterweight and rear axle mounting point, resulting in 30% of forklifts being unable to be upgraded due to structural incompatibility, and increasing retrofit labor costs by 2,000-3,000 yuan per unit.
[0007] With the development of intelligent warehousing technology, AGV forklifts have placed new demands on steering systems, requiring "high precision, fast response, and maintenance-free operation." In existing technologies, some electric steering axles use asynchronous motors, but these suffer from low efficiency (rated efficiency <75%) and high heat generation (continuous operating temperature >80℃). Structures using split sensors suffer from accuracy degradation due to installation errors, failing to meet the control requirement of ±0.01mm.1 Furthermore, traditional communication protocols mostly use analog signal transmission, which is susceptible to interference in the complex electromagnetic environment of forklifts, resulting in data transmission delays exceeding 50ms, thus failing to meet real-time control requirements. Therefore, it is necessary to design a new electric steering axle structure for forklifts. Summary of the Invention
[0008] The purpose of this invention is to provide an electric steering axle structure for forklifts to solve the problems mentioned in the background art.
[0009] To achieve the above objectives, the present invention provides the following technical solution: a forklift electric steering axle structure, comprising a steering axle body and an electric push rod;
[0010] The electric push rod is horizontally mounted on the steering axle body;
[0011] The electric push rod is fastened to the steering axle body by bolts.
[0012] Preferably, it also includes a permanent magnet synchronous motor, which is fixed to the electric push rod housing by a bracket, and the output shaft of the permanent magnet synchronous motor is connected to the lead screw transmission system inside the electric push rod by a coupling.
[0013] Preferably, it also includes a high-precision sensor, which is integrated inside the permanent magnet synchronous motor and fixed by a positioning groove and screws on the motor end cover.
[0014] Preferably, it also includes a motor controller, wherein the electric push rod is connected to the motor controller via a three-phase line, and the motor controller is connected to the low-voltage circuit of the vehicle via a low-voltage connector.
[0015] Preferably, the three-phase wires are anti-interference cables, and the low-voltage connectors are waterproof.
[0016] Preferably, the motor controller is connected to the vehicle control system via the CAN communication protocol, and a twisted-pair shielded cable is used as the communication cable.
[0017] Preferably, the sensing element of the high-precision sensor is embedded inside the rotor of the permanent magnet synchronous motor and arranged coaxially with the rotor magnetic poles. The signal processing circuit of the high-precision sensor is integrated inside the motor end cover. The high-precision sensor and the motor are formed into an integrated module by die casting of aluminum alloy.
[0018] Preferably, a method of using an electric steering axle structure for a forklift includes the following steps:
[0019] A. When the forklift needs to turn, the vehicle control system sends a steering command to the motor controller via the CAN communication protocol; B. After receiving the command, the motor controller controls the three-phase permanent magnet motor to rotate, converting the rotational motion into the linear motion of the electric push rod through the lead screw transmission, pushing the steering axle body to turn. The left and right travel of the electric push rod is ±80mm, and the response time from +70mm to -70mm is less than 2.4 seconds; C. High-precision sensors inside the motor monitor the position and movement status of the electric push rod in real time and feed the data back to the motor controller. The motor controller adjusts the motor rotation according to the feedback data to achieve a precision control of ±0.01mm; D. During the steering process, the electric push rod operates at a rated speed of 30mm / sec or a peak speed of 60mm / sec, and its maximum continuous thrust of 38Kn ensures steering power.
[0020] Beneficial effects:
[0021] (1) The present invention has a novel structural design and adopts a permanent magnet synchronous motor and a high-precision sensor design to achieve high-precision control, making the forklift steering more accurate and meeting the requirements of high-precision operation.
[0022] (2) The present invention has a maximum continuous thrust of 38Kn, a left and right stroke of ±80mm, a reaction time of less than 2.4 seconds from +70mm to -70mm, a rated speed of 30mm / sec, and a peak speed of 60mm / sec, which can provide sufficient power for forklift steering and ensure fast steering response and smooth operation.
[0023] (3) The present invention uses a three-phase permanent magnet motor to drive the lead screw, which converts the rotational motion into linear motion. The internal angle sensor of the motor precisely controls the position, ensuring the accuracy and stability of the transmission.
[0024] The above description is merely an overview of the technical solutions of the embodiments of this application. In order to better understand the technical means of the embodiments of this application and to implement them in accordance with the contents of the specification, and to make the above and other objects, features and advantages of the embodiments of this application more apparent and understandable, specific implementation methods of this application are described below. Attached Figure Description
[0025] Figure 1 This is a schematic diagram of the structure of the present invention;
[0026] Figure 2 This is the front view of the present invention;
[0027] Figure 3 This is a side view of the present invention;
[0028] In the diagram: 1. Steering axle body; 2. Electric push rod; 3. Permanent magnet synchronous motor; 4. High-precision sensor; 5. Motor controller; 6. Three-phase wire; 7. Low-voltage connector. Detailed Implementation
[0029] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.
[0030] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used herein in the specification of the application is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms “comprising” and “having”, and any variations thereof, in the specification, claims and drawings of this application are intended to cover non-exclusive inclusion.
[0031] The term "embodiment" as used herein means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of the phrase "embodiment" in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.
[0032] The directional terms appearing in the following description refer to the directions shown in the figures and are not intended to limit the specific structure of this application. For example, in the description of this application, terms such as "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the figures. They are used only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.
[0033] Furthermore, the descriptions of directions such as the X direction, Y direction, and Z direction used to explain the operation and construction of the components in this embodiment are not absolute but relative. Although these directions are appropriate when the components are in the positions shown in the figure, they should be interpreted differently when these positions change.
[0034] Furthermore, the terms "first," "second," etc., in the specification and claims of this application or in the aforementioned drawings are used to distinguish different objects rather than to describe a specific order, and may explicitly or implicitly include one or more of the features.
[0035] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, "connection" or "joining" in mechanical structures can refer to a physical connection, such as a fixed connection, for example, a connection fixed by fasteners, such as a connection fixed by screws, bolts, or other fasteners; a physical connection can also be a detachable connection, such as a snap-fit or interlocking connection; a physical connection can also be an integral connection, such as a connection formed by welding, bonding, or integral molding. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.
[0036] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings.
[0037] Please see Figures 1-3 The present invention discloses a forklift electric steering axle structure, including a steering axle body 1 and an electric push rod 2;
[0038] The electric push rod 2 is horizontally mounted on the steering axle body 1. The connecting parts of the electric push rod housing are sealed with O-rings, and the sealing level reaches IP67, which can effectively prevent dust, water and other impurities from entering the interior and protect the mechanical transmission parts and electrical components.
[0039] The electric push rod 2 is fastened to the steering axle body 1 by bolts.
[0040] The steering axle body supports the weight of the forklift and enables steering. An electric actuator, mounted on the steering axle body, provides a maximum continuous thrust of 38 kN, sufficient for steering. A permanent magnet synchronous motor connects to the electric actuator; employing a permanent magnet synchronous motor and high-precision sensor design, it achieves control accuracy of ±0.01 mm.
[0041] This invention also includes a permanent magnet synchronous motor 3, which is fixed to the electric push rod housing by a bracket. The output shaft of the permanent magnet synchronous motor 3 is connected to the lead screw transmission system inside the electric push rod 2 via a coupling. It also includes a motor controller 5, which is connected to the electric push rod 2 via a three-phase cable 6. The motor controller 5 is connected to the vehicle's low-voltage circuit via a low-voltage connector 7. The three-phase cable 6 is an anti-interference cable, and the low-voltage connector 7 is waterproof. The motor controller 5 is connected to the vehicle control system via the CAN communication protocol, using twisted-pair shielded cable as the communication cable. Using the CAN communication protocol ensures consistent communication with the vehicle, guaranteeing the stability and timeliness of information transmission. The electric push rod has a left and right travel of ±80mm, a response time of less than 2.4 seconds from +70mm to -70mm, a rated speed of 30mm / sec, and a peak speed of 60mm / sec, meeting the steering requirements of the forklift under different working conditions. This invention uses a three-phase permanent magnet motor to drive a lead screw, converting rotational motion into linear motion. An internal angle sensor in the motor precisely controls the position, ensuring the accuracy and stability of the transmission.
[0042] This invention also includes a high-precision sensor 4, which is integrated inside the permanent magnet synchronous motor 3 and fixed with screws via a positioning groove in the motor end cover. The sensing element of the high-precision sensor 4 is embedded inside the rotor of the permanent magnet synchronous motor and arranged coaxially with the rotor magnetic poles. The signal processing circuit of the high-precision sensor is integrated inside the motor end cover. The high-precision sensor and the motor are integrally formed into a single module by die-casting aluminum alloy. The flatness error is less than 0.01mm, and a double-layer sealing ring is provided at the mating surface to achieve an IP67 sealing rating while preventing external vibration from interfering with the sensor signal. When the permanent magnet synchronous motor rotor rotates, the sensing element of the sensor embedded inside the rotor rotates synchronously with the rotor, detecting the rotor position angle in real time through magnetoelectric induction or photoelectric induction principles. After the sensor converts the angle signal into an electrical signal, it is filtered, amplified, and converted from analog to digital by the signal processing circuit integrated in the end cover, and finally transmitted to the motor controller via the CAN communication protocol. The controller adjusts the motor speed and direction in real time according to the position signal, forming a closed-loop control to achieve high-precision position control of the electric actuator within ±0.01mm.
[0043] Working principle: A method for using an electric steering axle structure for forklifts includes the following steps:
[0044] A. When the forklift needs to turn, the vehicle control system sends a steering command to the motor controller via the CAN communication protocol; B. After receiving the command, the motor controller controls the three-phase permanent magnet motor to rotate, converting the rotational motion into the linear motion of the electric push rod through the lead screw transmission, pushing the steering axle body to turn. The left and right travel of the electric push rod is ±80mm, and the response time from +70mm to -70mm is less than 2.4 seconds; C. High-precision sensors inside the motor monitor the position and movement status of the electric push rod in real time and feed the data back to the motor controller. The motor controller adjusts the motor rotation according to the feedback data to achieve a precision control of ±0.01mm; D. During the steering process, the electric push rod operates at a rated speed of 30mm / sec or a peak speed of 60mm / sec, and its maximum continuous thrust of 38Kn ensures steering power.
[0045] This forklift electric steering axle structure offers significant advantages in practical applications. The use of a permanent magnet synchronous motor and high-precision sensors greatly improves steering accuracy, meeting the demands of high-precision operations. The use of the CAN communication protocol further enhances the coordination between this structure and the vehicle's overall communication, improving system response speed and stability.
[0046] The design, which does not modify the forklift's counterweight and rear axle mounting points, not only simplifies installation and maintenance but also reduces costs. Its IP67 sealing rating allows it to operate in harsh environments, reducing the probability of malfunctions.
[0047] In terms of lifespan, a lifespan of 5.4 million cycles ensures the reliability of the structure during long-term use, reducing maintenance costs and replacement frequency. Air cooling effectively lowers the motor temperature, ensuring normal motor operation.
[0048] In summary, the present invention features a novel structural design, employing a permanent magnet synchronous motor and high-precision sensors to achieve high-precision control, making forklift steering more accurate and meeting the requirements of high-precision operations.
[0049] The above-described embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application.
Claims
1. A structure of an electrically steered axle for a fork lift truck, characterized by: Including the steering bridge body (1), electric push rod (2); The electric push rod (2) is horizontally installed on the steering bridge body (1); The electric push rod (2) is connected with the steering bridge body (1) through bolt fastening.
2. The electrically steered axle structure for a fork truck of claim 1, wherein: Also includes permanent magnet synchronous motor (3), the permanent magnet synchronous motor (3) is fixed on the electric push rod shell through the support, the output shaft of the permanent magnet synchronous motor (3) is connected with the lead screw transmission system in the electric push rod (2) through the shaft coupling.
3. The electrically steered axle structure for a fork truck of claim 1, wherein: Also includes high-precision sensor (4), the high-precision sensor (4) is integrated in the permanent magnet synchronous motor (3), fixed through the positioning groove of the motor end cover and screw.
4. The electrically steered axle structure for a fork truck of claim 1, wherein: Also includes motor controller (5), the electric push rod (2) is connected with the motor controller (5) through three-phase line (6), the motor controller (5) is connected with the whole vehicle low-voltage circuit through low-voltage connector (7).
5. The electrically steered axle structure for a fork truck as set forth in claim 4, wherein: The three-phase line (6) adopts anti-interference cable, and the low-voltage connector (7) is waterproof type.
6. The electrically steered axle structure for a fork truck as set forth in claim 4, wherein: The motor controller (5) is connected with the whole vehicle control system through CAN communication protocol, and double-twisted shielded wire is used as communication cable.
7. The electrically steered axle structure for a fork truck as set forth in claim 3, wherein: The sensing element of the high-precision sensor (4) is embedded in the rotor of the permanent magnet synchronous motor and arranged coaxially with the rotor magnetic pole, the signal processing circuit of the high-precision sensor is integrated on the inner side of the motor end cover, and the high-precision sensor and the motor are integrated into a module by aluminum alloy pressure casting.
8. A method of using the electrically steered axle structure of claim 1, characterized in that: The method comprises the following steps: A. When the forklift needs to turn, the whole vehicle control system sends a steering instruction to the motor controller through CAN communication protocol; B. After receiving the instruction, the motor controller controls the three-phase permanent magnet motor to rotate, converts the rotary motion into linear motion of the electric push rod through the lead screw transmission, and pushes the steering bridge body to turn, wherein the left and right stroke of the electric push rod is ±80mm, and the reaction time from +70mm to-70mm is less than 2.4 seconds;C. The high-precision sensor in the motor monitors the position and motion state of the electric push rod in real time, and feeds back the data to the motor controller, and the motor controller adjusts the rotation of the motor according to the feedback data to realize the accuracy control of ±0.01mm; D. During the steering process, the electric push rod runs at a rated speed of 30mm / sec or a peak speed of 60mm / sec, and its maximum continuous thrust of 38Kn ensures the steering power.