An electrically powered steering axle assembly for a fork truck

Abstract

The utility model belongs to the technical field of fork truck, especially point to a kind of electric steering axle assembly suitable for fork truck, including steering axle assembly, the both ends of steering axle assembly are rotatable knuckle arm, the inner side end of knuckle arm is hinged with the outer end of steering drag link, the middle part of steering axle assembly is provided with steering motor, the motor rotor of this steering motor is synchronously rotatable connection with lead screw shell, lead screw shell is screwed in the middle part of lead screw shaft, the both ends of lead screw shaft are respectively linked with corresponding side steering drag link, motor rotor synchronously rotatable connection speed input gear, speed output gear is rotatably connected on steering motor, and speed sensor is used to detect the rotating speed of speed output gear.The utility model adopts the lead screw nut pair that lead screw shell and lead screw shaft constitute, the rotary motion of steering motor is converted into the linear motion of lead screw shaft, greatly simplifies the transmission chain structure, and the rotating speed signal of steering motor is detected in real time and fed back by means of speed sensor, realizes accurate closed-loop control.

Description

Technical Field

[0001] This utility model belongs to the field of forklift technology, and specifically refers to an electric steering axle assembly suitable for forklifts. Background Technology

[0002] Currently, forklifts generally use hydraulic steering systems (HPS) or electro-hydraulic power steering systems (EHPS). Hydraulic steering systems have disadvantages such as high energy consumption, easy hydraulic oil leakage, high maintenance costs, and complex structure. On the other hand, existing electric power steering technology has problems such as insufficient steering force, low control precision, and insufficient compact structure in forklift applications, making it difficult to meet the steering requirements of forklifts under heavy load conditions. Summary of the Invention

[0003] The purpose of this invention is to provide an electric steering axle assembly suitable for forklifts. It adopts a screw and nut pair consisting of a screw housing and a screw shaft, which converts the rotational motion of the steering motor into the linear motion of the screw shaft, greatly simplifying the transmission chain structure. It also uses a speed sensor to detect and feedback the speed signal of the steering motor in real time, thereby achieving precise closed-loop control.

[0004] This utility model is implemented as follows: An electric steering axle assembly suitable for forklifts includes a steering axle assembly with steering knuckle arms rotatably mounted at both ends. The outer ends of the steering knuckle arms are connected to steering hubs, and the inner ends of the steering knuckle arms are hinged to the outer ends of steering tie rods. A steering motor is laterally mounted in the middle of the steering axle assembly. The rotor of the steering motor is synchronously connected to a lead screw housing, which has a sleeve structure and is threaded onto the middle of the lead screw shaft. The left and right ends of the lead screw shaft extend outwards from the steering motor and are linked to the inner ends of the corresponding steering tie rods. The rotor of the steering motor is synchronously connected to a speed input gear, and a speed output gear meshing with the speed input gear is rotatably connected to the steering motor. A speed sensor mounted on the steering motor is used to detect the rotational speed of the speed output gear. Both the speed sensor and the steering motor are electrically connected to a control assembly, which controls the operating state of the steering motor based on the signal from the speed sensor.

[0005] In the above-mentioned electric steering axle assembly suitable for forklifts, the housing of the steering motor includes a motor inner housing, and a motor left end cover and a motor right end cover respectively covering the motor inner housing. The motor rotor and the motor stator that cooperates with the motor rotor are disposed in the motor inner housing. The left and right ends of the motor rotor and the lead screw housing are respectively synchronously rotatably connected to the lead screw housing left pressure plate and the lead screw housing right pressure plate. Lead screw angular contact bearings are provided between the lead screw housing left pressure plate and the motor left end cover, and between the lead screw housing right pressure plate and the motor right end cover. The left and right ends of the lead screw shaft are through-fitted on the motor left end cover and the motor right end cover.

[0006] In the aforementioned electric steering axle assembly suitable for forklifts, the speed input gear is mounted on the left or right pressure plate of the lead screw housing, and the speed output gear is rotatably connected to the left or right end cover of the motor via a shaft pin.

[0007] In the above-mentioned electric steering axle assembly suitable for forklifts, the number of teeth of the speed input gear is greater than the number of teeth of the speed output gear, and the transmission ratio between the speed input gear and the speed output gear is greater than or equal to 3:1.

[0008] In the aforementioned electric steering axle assembly suitable for forklifts, bearing bushes are provided between the left and right end covers of the motor and the lead screw shaft.

[0009] In the above-mentioned electric steering axle assembly suitable for forklifts, both the left and right end covers of the motor located outside the bearing bush are covered with O-ring end covers fitted on the lead screw shaft, and an O-ring is provided between the inner wall of the O-ring end cover and the lead screw shaft.

[0010] In the above-mentioned electric steering axle assembly suitable for forklifts, the left and right ends of the lead screw shaft are connected to pressure sensors via couplings, and the outer end of the pressure sensor is connected to a steering end seat, which is hinged to the inner end of the corresponding side steering tie rod.

[0011] In the aforementioned electric steering axle assembly suitable for forklifts, a telescopic accordion-style protective cover is provided between the steering end seat and the corresponding side wall of the steering motor.

[0012] In the above-mentioned electric steering axle assembly suitable for forklifts, the control assembly is electrically connected to the steering wheel torque sensor and the vehicle speed sensor. The steering wheel torque sensor can transmit the driver's steering torque signal to the control assembly, and the vehicle speed sensor can transmit the current vehicle speed signal to the control assembly. The control assembly controls the working state of the steering motor according to the signals from the steering wheel torque sensor and the vehicle speed sensor.

[0013] The outstanding advantages of this utility model compared to the prior art are: 1. This utility model adopts a lead screw and nut pair composed of a lead screw housing and a lead screw shaft, that is, the output shaft of the motor and the lead screw and nut pair are integrated into one design, so that the rotational motion of the steering motor is converted into the linear motion of the lead screw shaft, which greatly simplifies the transmission chain structure. Compared with the existing technology, the transmission structure of this design is more compact and the transmission efficiency is higher. At the same time, it can also completely eliminate the leakage risk and energy consumption problem of the existing hydraulic system, achieving energy saving of more than 40%. 2. The speed of the steering motor is amplified by the speed input gear and speed output gear. The speed sensor detects the speed signal of the steering motor in real time and feeds it back to the control assembly. This not only effectively improves the speed detection resolution, but also realizes precise closed-loop control, which is especially suitable for low-speed heavy-load forklift operation. Attached Figure Description

[0014] Figure 1 This is a three-dimensional view of the overall structure of this utility model; Figure 2 This is a cross-sectional view of the overall structure of this utility model.

[0015] In the diagram: 1. Steering axle assembly; 2. Steering knuckle arm; 3. Steering hub; 4. Steering tie rod; 5. Steering motor; 6. Motor rotor; 7. Leadscrew housing; 8. Leadscrew shaft; 9. Speed ​​input gear; 10. Speed ​​output gear; 11. Motor housing; 12. Motor left end cover; 13. Motor right end cover; 14. Motor stator; 15. Leadscrew housing left pressure plate; 16. Leadscrew housing right pressure plate; 17. Leadscrew angular contact bearing; 18. Bearing bush; 19. O-ring end cover; 20. O-ring; 21. Pressure sensor; 22. Steering end seat; 23. Bellows-style protective cover. Detailed Implementation

[0016] The present invention will be further described below with reference to specific embodiments. See also: Figure 1 —2: An electric steering axle assembly suitable for forklifts includes a steering axle assembly 1, with steering knuckle arms 2 rotatably mounted at both ends of the steering axle assembly 1. A steering hub 3 is connected to the outer end of each steering knuckle arm 2, and the inner end of each steering knuckle arm 2 is hinged to the outer end of a steering tie rod 4. A steering motor 5 is laterally mounted in the middle of the steering axle assembly 1. The motor rotor 6 of the steering motor 5 is synchronously connected to a lead screw housing 7, which has a sleeve structure and is threaded onto the middle of a lead screw shaft 8. The left and right ends of the lead screw shaft 8 extend outwards from the steering motor 5 and are linked to the inner ends of the corresponding steering tie rods 4. The motor rotor 6 of the steering motor 5 is synchronously connected to a speed input gear 9. A speed output gear 10, meshing with the speed input gear 9, is rotatably connected to the steering motor 5. A speed sensor mounted on the steering motor 5 is used to detect the rotational speed of the speed output gear 10. The speed sensor and the steering motor 5 are electrically connected to a control assembly, which controls the operating state of the steering motor 5 based on the signal from the speed sensor. That is, the steering motor 5 drives the lead screw housing 7 to rotate in the forward or reverse direction through the motor rotor 6, and the lead screw shaft 8, which is threaded with the lead screw housing 7, moves laterally to the left or right, thereby driving the two steering knuckle arms 2 and the steering wheel hub 3 to rotate through the steering tie rod 4.

[0017] This invention employs a lead screw and nut assembly consisting of a lead screw housing 7 and a lead screw shaft 8, integrating the motor's output shaft with the lead screw and nut assembly into a single design. This transforms the rotational motion of the steering motor 5 into the linear motion of the lead screw shaft 8, significantly simplifying the transmission chain structure. Compared to existing technologies, this design features a more compact transmission structure and higher transmission efficiency. Furthermore, it completely eliminates the leakage risks and energy consumption problems of existing hydraulic systems, achieving energy savings of over 40%. In addition, the speed input gear 9 and speed output gear 10 amplify the rotational speed of the steering motor 5. A speed sensor detects this speed in real time and feeds back the rotational speed signal of the steering motor 5 to the control assembly. This not only effectively improves the speed detection resolution but also achieves precise closed-loop control, making it particularly suitable for low-speed, heavy-load forklift operations.

[0018] Furthermore, the housing of the steering motor 5 includes a motor inner housing 11, and a left end cover 12 and a right end cover 13 on the motor inner housing 11. The motor rotor 6 and the motor stator 14 that cooperate with the motor rotor 6 are disposed inside the motor inner housing 11. The left and right ends of the motor rotor 6 and the lead screw housing 7 are synchronously rotatably connected to the left pressure plate 15 and the right pressure plate 16 of the lead screw housing, respectively. Angular contact bearings 17 are provided between the left pressure plate 15 and the left end cover 12, and between the right pressure plate 16 and the right end cover 13 of the motor. The left and right ends of the lead screw shaft 8 are threaded through and fitted onto the left end cover 12 and the right end cover 13 of the motor. The angular contact bearings 17 provide reliable and effective support for the left pressure plate 15, the motor rotor 6, the lead screw housing 7, the right pressure plate 16, and the lead screw shaft 8, ensuring the overall structural rigidity and reliability of the steering motor 5, thus achieving a longer service life.

[0019] In this embodiment, the speed input gear 9 and the speed output gear 10 are specifically configured as follows: the speed input gear 9 is mounted on the right pressure plate 16 of the lead screw housing, and the speed output gear 10 is rotatably connected to the right end cover 13 of the motor via a shaft pin. Correspondingly, the speed sensor is fixed on the motor stator 14 or the motor housing 11 located inside the right end cover 13 of the motor.

[0020] In order to enable the acceleration gear set composed of speed input gear 9 and speed output gear 10 to effectively amplify the rotational speed so that the speed sensor can perform accurate detection, the number of teeth of speed input gear 9 is greater than the number of teeth of speed output gear 10, and the transmission ratio between speed input gear 9 and speed output gear 10 is greater than or equal to 3:1.

[0021] Meanwhile, in order to enable the lead screw shaft 8 to move stably in the left and right directions on the left end cover 12 and the right end cover 13 of the motor, a bearing bush 18 is provided between the left end cover 12 and the right end cover 13 of the motor and the lead screw shaft 8.

[0022] Furthermore, to prevent external water from entering the gap between the lead screw shaft 8 and the left end cover 12 or the right end cover 13 of the motor and interfering with the normal operation of the steering motor 5, the left end cover 12 and the right end cover 13 of the motor located outside the bearing 18 are both covered with O-ring end caps 19 that are fitted onto the lead screw shaft 8, and an O-ring 20 is provided between the inner wall of the O-ring end cap 19 and the lead screw shaft 8.

[0023] Furthermore, considering that forcibly steering the steering motor 5 could damage it if the steering wheel is restricted from rotating normally, the left and right ends of the lead screw shaft 8 are connected to pressure sensors 21 via couplings. The outer end of the pressure sensor 21 is connected to a steering end seat 22, which is hinged to the inner end of the corresponding side steering tie rod 4. That is, when the pressure sensor 21 detects that the pressure exceeds a threshold, the control assembly receives the signal from the pressure sensor 21 and controls the steering motor 5 to stop working, thus effectively protecting the steering motor 5. In addition, the pressure sensor 21 can also be used to detect the driving force during steering wheel calibration.

[0024] Furthermore, in order to prevent external objects from interfering with the lead screw shaft 8, a telescopic accordion-style protective cover 23 is provided between the steering end seat 22 and the corresponding side wall of the steering motor 5.

[0025] Furthermore, in practical applications in forklifts, the control assembly is electrically connected to the steering wheel torque sensor and the vehicle speed sensor. The steering wheel torque sensor can transmit the driver's steering torque signal to the control assembly, and the vehicle speed sensor can transmit the current vehicle speed signal to the control assembly. The control assembly controls the working state of the steering motor 5 based on the signals from the steering wheel torque sensor and the vehicle speed sensor.

[0026] The steering wheel torque sensor transmits the driver's steering torque signal to the control assembly. The control assembly sends a motor drive signal to the steering motor 5 based on the current vehicle speed signal transmitted by the vehicle speed sensor. This signal can be a PWM wave. The steering motor 5 converts the rotational motion into linear motion through the lead screw housing 7 and the lead screw shaft 8 to drive the steering tie rod 4 and the steering wheel hub 3 to rotate. At the same time, the acceleration gear set of the speed input gear 9 and the speed output gear 10 amplifies the speed of the steering motor 5. The speed sensor accurately detects the speed of the speed output gear 10 in real time and feeds the speed signal back to the control assembly. The control assembly controls the working state of the steering motor 5 based on the speed signal. The working state includes increasing the output speed, decreasing the output speed, idling, and stopping operation.

[0027] The above embodiments are only one of the preferred embodiments of this utility model and are not intended to limit the scope of implementation of this utility model. Therefore, all equivalent changes made to the shape, structure and principle of this utility model should be covered within the protection scope of this utility model.

Claims

1. An electric steering axle assembly suitable for forklifts, comprising a steering axle assembly (1), with steering knuckle arms (2) rotatably mounted at both ends of the steering axle assembly (1), a steering hub (3) connected to the outer end of the steering knuckle arm (2), and the inner end of the steering knuckle arm (2) hinged to the outer end of a steering tie rod (4), characterized in that: A steering motor (5) is laterally arranged in the middle of the steering axle assembly (1). The motor rotor (6) of the steering motor (5) is synchronously connected to the lead screw housing (7). The lead screw housing (7) is a sleeve structure and is threaded onto the middle of the lead screw shaft (8). The left and right ends of the lead screw shaft (8) extend outward from the steering motor (5) and are linked to the inner end of the corresponding side steering tie rod (4). The motor rotor (6) of the steering motor (5) is synchronously connected to the speed input gear (9). A speed output gear (10) that meshes with the speed input gear (9) is rotatably connected to the steering motor (5). A speed sensor installed on the steering motor (5) is used to detect the rotational speed of the speed output gear (10). The speed sensor and the steering motor (5) are electrically connected to the control assembly. The control assembly controls the working state of the steering motor (5) according to the signal from the speed sensor.

2. The electric steering axle assembly for forklifts according to claim 1, characterized in that: The housing of the steering motor (5) includes a motor housing (11), and a motor left end cover (12) and a motor right end cover (13) covering the motor housing (11). The motor rotor (6) and the motor stator (14) cooperating with the motor rotor (6) are arranged inside the motor housing (11). The left and right ends of the motor rotor (6) and the lead screw housing (7) are synchronously connected to the lead screw housing left pressure plate (15) and the lead screw housing right pressure plate (16). Lead screw angular contact bearings (17) are provided between the lead screw housing left pressure plate (15) and the motor left end cover (12), and between the lead screw housing right pressure plate (16) and the motor right end cover (13). The left and right ends of the lead screw shaft (8) are connected through the motor left end cover (12) and the motor right end cover (13).

3. The electric steering axle assembly for forklifts according to claim 2, characterized in that: The speed input gear (9) is mounted on the left pressure plate (15) or the right pressure plate (16) of the screw housing, and the speed output gear (10) is rotatably connected to the left end cover (12) or the right end cover (13) of the motor via a shaft pin.

4. An electric steering axle assembly suitable for forklifts according to claim 1 or 3, characterized in that: The number of teeth of the speed input gear (9) is greater than the number of teeth of the speed output gear (10), and the transmission ratio between the speed input gear (9) and the speed output gear (10) is greater than or equal to 3:

1.

5. An electric steering axle assembly suitable for forklifts according to claim 2, characterized in that: A bearing bush (18) is provided between the left end cover (12) and the right end cover (13) of the motor and the lead screw shaft (8).

6. An electric steering axle assembly suitable for forklifts according to claim 5, characterized in that: The left end cover (12) and the right end cover (13) of the motor located outside the bearing (18) are both covered with O-ring end caps (19) fitted on the lead screw shaft (8), and an O-ring (20) is provided between the inner wall of the O-ring end cap (19) and the lead screw shaft (8).

7. An electric steering axle assembly suitable for forklifts according to claim 1, characterized in that: The left and right ends of the lead screw shaft (8) are connected to pressure sensors (21) via couplings. The outer end of the pressure sensor (21) is connected to a steering end seat (22), which is hinged to the inner end of the corresponding side steering tie rod (4).

8. An electric steering axle assembly suitable for forklifts according to claim 7, characterized in that: A telescopic bellows-style protective cover (23) is provided between the steering end seat (22) and the corresponding side wall of the steering motor (5).

9. An electric steering axle assembly suitable for forklifts according to claim 1, characterized in that: The control assembly is electrically connected to the steering wheel torque sensor and the vehicle speed sensor. The steering wheel torque sensor can transmit the driver's steering torque signal to the control assembly, and the vehicle speed sensor can transmit the current vehicle speed signal to the control assembly. The control assembly controls the working state of the steering motor (5) according to the signals from the steering wheel torque sensor and the vehicle speed sensor.

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