A steering input shaft in an automotive electric power assisted steering system

Abstract

The utility model relates to the field of automobile engineering discloses a kind of steering input shaft in automobile electric power steering system, including driving shaft, the driving shaft one end is fixedly connected on automobile steering wheel, the driving shaft other end inside slidingly connected with driven shaft, the driven shaft and passive retraction mechanism junction is provided with passive retraction mechanism, the driven shaft is fixedly connected with gear away from the one end of driving shaft, the driven shaft inside is provided with oiling mechanism, the passive retraction mechanism includes internal spline.The utility model in, passive retraction mechanism can take into account the transmission stability and collision safety of steering input shaft.When normal driving, internal spline and external spline engagement ensure that driving shaft is stably transmitted steering torque to driven shaft, when the axial force generated by collision reaches threshold value, shear pin will break unlock, make driving shaft and driven shaft relatively contract along spline direction, effectively avoid shaft body intrusion cockpit.

Description

Technical Field

[0001] This utility model relates to the field of automotive engineering, and in particular to a steering input shaft in an automotive electric power steering system. Background Technology

[0002] The steering input shaft in an electric power steering system is mainly used to connect the steering wheel operated by the driver and the steering gear. It is widely used in the automotive manufacturing industry. Its core function is to transmit the steering torque and steering angle signals applied by the driver to the controller and steering gear of the electric power steering system, providing precise input for the generation of power steering commands. Currently, the steering input shaft on the market is mainly composed of a shaft made of high-quality alloy steel, flanges at both ends for connection, a rectangular spline mating structure for transmitting power, bearings that provide support, and rubber dust covers that protect against dust. It mainly achieves the effect of zero play in steering operation, stable response of electric power steering system, and smooth driving control by using the torque transmission capacity of rigid shaft and the precise fit of spline, combined with the smooth support of bearing. In existing automotive electric power steering systems, the steering input shaft may intrude into the passenger compartment due to the impact force during a severe collision, endangering the driver's life. Therefore, a new steering input shaft for automotive electric power steering systems is proposed to solve the above problem. Utility Model Content

[0003] To overcome the above deficiencies, this utility model provides a steering input shaft in an automotive electric power steering system, aiming to improve the problem in the prior art where the shaft may intrude into the passenger compartment due to the impact force of a severe collision.

[0004] To achieve the above objectives, the present invention adopts the following technical solution: a steering input shaft in an automotive electric power steering system, comprising a drive shaft, one end of which is fixedly connected to the automotive steering wheel, and a driven shaft slidably connected inside the other end of the drive shaft. A passive retraction mechanism is provided at the connection between the driven shaft and the passive retraction mechanism. A gear is fixedly connected to the end of the driven shaft away from the drive shaft, and an oil injection mechanism is provided inside the driven shaft. The passive retraction mechanism includes an internal spline, which is formed on the bottom inner wall of the drive shaft. Four shear pins are fixedly connected to the inner wall of the drive shaft. Shear grooves are formed on the outside of the shear pins. An external spline is fixedly connected to the outer wall of the driven shaft. Four slots are formed at the top of the driven shaft. The shear pins and slots match. The internal spline and external spline engage. As a further description of the above technical solution: The oil injection mechanism includes an oil storage area, which is located inside the gear. An oil injection pipe is provided on the top wall of the oil storage area, and an oil outlet groove is provided on the side wall of the oil storage area. A limit ring is fixedly connected to the inner wall of the oil outlet groove, and an oil outlet pipe is slidably connected to the inner wall of the oil outlet groove. A spring is provided inside the oil outlet groove. As a further description of the above technical solution: A sealing ring is fixedly connected inside the oil injection pipe, and a threaded groove is opened on the inner wall of the oil injection pipe. A threaded cap is threadedly connected to the inner wall of the threaded groove. As a further description of the above technical solution: One end of the spring is fixedly connected to the outer wall of the limiting ring, and the other end of the spring is fixedly connected to the outer wall of the oil outlet pipe; As a further description of the above technical solution: The oil outlet pipe abuts against the inner wall of the oil outlet tank; As a further description of the above technical solution: The threaded cap abuts against the outer wall of the sealing ring; As a further description of the above technical solution: A dust cover is provided on the outside of the connection between the drive shaft and the driven shaft. Sealing sleeves are fixedly connected to the top and bottom inner walls of the dust cover, and the sealing sleeves abut against the outer walls of the drive shaft and the driven shaft respectively.

[0005] This utility model has the following beneficial effects: 1. In this utility model, the passive retraction mechanism can balance the transmission stability and collision safety of the steering input shaft. During normal driving, the engagement of the internal and external splines ensures stable transmission of steering torque from the driving shaft to the driven shaft, while the shear pin restricts relative sliding between the two to maintain the overall rigidity of the shaft. When the axial force generated by a collision reaches a threshold, the shear pin will break and release the lock, causing the driving shaft and the driven shaft to retract relative to each other along the spline direction, effectively preventing the shaft from intruding into the cockpit and providing safety protection for the driver.

[0006] 2. In this utility model, the oil injection mechanism can efficiently provide lubrication to the mating parts of the shaft, ensuring smooth transmission of the steering input shaft over a long period of time. The oil reservoir can store lubricating oil, and the oil injection pipe facilitates the replenishment of grease; when the gear rotates and presses against the oil outlet pipe, the grease pressure in the oil reservoir increases, and the grease can flow out along the oil outlet pipe to lubricate the key parts, maintaining the stable transmission performance of the shaft. Attached Figure Description

[0007] Figure 1 This is a three-dimensional schematic diagram of the steering input shaft in an electric power steering system for automobiles proposed in this utility model. Figure 2 This is a schematic diagram of the structure of a slot for the steering input shaft in an electric power steering system for automobiles, as proposed in this utility model. Figure 3 This is a schematic diagram of the structure of the shear pin of the steering input shaft in an electric power steering system for automobiles, as proposed in this utility model. Figure 4 This is a schematic diagram of the oil injection pipe of the steering input shaft in an electric power steering system for automobiles, as proposed in this utility model. Figure 5 for Figure 4 Enlarged view of point A in the middle; Figure 6 for Figure 4 Enlarged view of point B in the middle.

[0008] Legend: 1. Driven shaft; 2. Driven shaft; 3. Passive retraction mechanism; 4. Gear; 5. Oil injection mechanism; 6. Internal spline; 7. Shear pin; 8. Shear groove; 9. External spline; 10. Slot; 11. Dust cover; 12. Sealing sleeve; 13. Oil injection pipe; 14. Oil reservoir; 15. Sealing ring; 16. Threaded groove; 17. Threaded cap; 18. Limiting ring; 19. Oil outlet pipe; 20. Spring; 21. Oil outlet groove. Detailed Implementation

[0009] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0010] Reference Figure 1 An embodiment of this utility model provides a steering input shaft in an electric power steering system for automobiles, including a drive shaft 1. One end of the drive shaft 1 is fixedly connected to the automobile steering wheel, and the other end of the drive shaft 1 is internally slidably connected to a driven shaft 2. A passive retraction mechanism 3 is provided at the connection between the driven shaft 2 and the drive shaft 1. A gear 4 is fixedly connected to the end of the driven shaft 2 away from the drive shaft 1, and an oil injection mechanism 5 is provided inside the driven shaft 2.

[0011] The drive shaft 1 receives the steering force and steering angle applied by the driver through the steering wheel, and transmits them to the gear 4 through a sliding connection with the driven shaft 2. The gear 4 then transmits the power to the steering system. The passive retraction mechanism 3 is used to achieve relative retraction between the drive shaft 1 and the driven shaft 2 in the event of a collision. The lubrication mechanism 5 provides lubrication to the shaft mating parts to ensure smooth overall transmission.

[0012] Reference Figures 1-3The passive contraction mechanism 3 includes an internal spline 6, which is formed on the bottom inner wall of the drive shaft 1. Four shear pins 7 are fixedly connected to the inner wall of the drive shaft 1. Shear pins 7 have shear grooves 8 on their outer sides. An external spline 9 is fixedly connected to the outer wall of the driven shaft 2. Four slots 10 are formed at the top of the driven shaft 2. The shear pins 7 and slots 10 are matched, and the internal spline 6 and external spline 9 are engaged.

[0013] During normal driving, the inner spline 6 and the outer spline 9 mesh with each other to ensure that the steering torque of the drive shaft 1 is stably transmitted to the driven shaft 2; the shear pin 7 is inserted into the slot 10 to restrict the relative sliding between the drive shaft 1 and the driven shaft 2 and maintain the overall rigidity of the shaft; when the axial force generated by the collision reaches the threshold, the shear pin 7 will break at the shear groove 8, releasing the lock between the two, so that the drive shaft 1 and the driven shaft 2 can retract relative to each other along the spline direction.

[0014] Reference Figure 1 , Figure 4 and Figure 5 The oil injection mechanism 5 includes an oil storage area 14, which is located inside the gear 4. An oil injection pipe 13 is provided on the top wall of the oil storage area 14, and an oil outlet groove 21 is provided on the side wall of the oil storage area 14. A limit ring 18 is provided on the inner wall of the oil outlet groove 21, and an oil outlet pipe 19 is slidably connected to the inner wall of the oil outlet groove 21. A spring 20 is provided inside the oil outlet groove 21.

[0015] The oil reservoir 14 serves as a storage space for lubricating oil. Located inside the gear 4, it allows for close-range lubrication of parts requiring lubrication, such as the splined joint of the steering input shaft, reducing the grease transport distance. The oil filling pipe 13 replenishes lubricating oil to the oil reservoir 14; when the grease in the reservoir 14 is insufficient, new grease can be injected through this pipe. The oil outlet groove 21 is the channel for lubricating oil to flow from the oil reservoir 14 to the lubrication points. The limiting ring 18 restricts the sliding range of the oil outlet pipe 19 and the spring 20, preventing the oil outlet pipe 19 from detaching from the oil outlet groove 21 and the spring 20 from being excessively compressed or stretched. Under normal conditions, the spring 20 applies a pushing force to the oil outlet pipe 19, causing it to fit tightly against the inner wall of the oil outlet groove 21. When lubrication is needed, the grease in the oil reservoir 14 can be pushed by slight pressure, such as the slight vibration and squeezing action during shaft transmission, to slide the oil outlet pipe 19 and compress the spring 20. At this time, the grease flows out through the oil outlet pipe 19 and enters the parts requiring lubrication, achieving a lubrication effect. When in its uncompressed, natural state, a portion of the tube extends out from inside gear 4.

[0016] Reference Figure 1 , Figure 4 and Figure 6 The oil injection pipe 13 is fixedly connected to a sealing ring 15, and the inner wall of the oil injection pipe 13 is provided with a threaded groove 16, and the inner wall of the threaded groove 16 is threadedly connected with a threaded cap 17.

[0017] The sealing ring 15 of the oil injection pipe 13 enhances the pipe's sealing performance and prevents grease in the oil storage area 14 from leaking from the pipe opening; the threaded cap 17 seals the oil injection pipe 13 by threadedly engaging with the threaded groove 16, preventing dust and impurities from entering the oil storage area 14 and contaminating the grease.

[0018] Reference Figure 6 One end of the spring 20 is fixedly connected to the outer wall of the limiting ring 18, and the other end of the spring 20 is fixedly connected to the outer wall of the oil outlet pipe 19.

[0019] When the spring 20 is in its natural state, it will apply a thrust to the oil outlet pipe 19, causing the oil outlet pipe 19 to fit tightly against the inner wall of the oil outlet groove 21. When the grease pressure in the oil storage area 14 increases, the spring 20 is compressed, creating a gap between the oil outlet pipe 19 and the oil outlet groove 21, allowing the grease to flow out along the oil outlet pipe 19.

[0020] Reference Figure 5 The threaded cap 17 abuts against the outer wall of the sealing ring 15.

[0021] After the threaded cap 17 abuts against the sealing ring 15, it can further enhance the sealing effect of the oil injection pipe 13. Through the double seal of threaded fit and end face abutment, it prevents the grease in the oil storage area 14 from leaking out of the pipe opening, and at the same time blocks external debris from entering.

[0022] Reference Figures 1-3 A dust cover 11 is provided on the outside of the connection between the drive shaft 1 and the driven shaft 2. A sealing sleeve 12 is fixedly connected to the inner wall of the top and bottom of the dust cover 11. The sealing sleeve 12 abuts against the outer wall of the drive shaft 1 and the driven shaft 2 respectively.

[0023] The dust cover 11 wraps around the connection between the drive shaft 1 and the driven shaft 2 to prevent external dust, moisture, mud and sand from entering the spline mating surface or the passive shrinking mechanism 3. The sealing sleeve 12 further enhances the sealing performance of the dust cover 11 by abutting against the drive shaft 1 and the driven shaft 2, while also accommodating the slight relative movement of the shaft during shrinking or normal operation, thus preventing wear of the dust cover 11.

[0024] Reference Figures 1-3 When manufacturing the input shaft, the shear pin 7 can be installed inside the slot 10 and then inserted into the drive shaft 1 for welding, which facilitates production.

[0025] Working principle: The drive shaft 1 receives the steering force and steering angle applied by the driver through the steering wheel, and transmits power through a sliding connection with the driven shaft 2. In the passive retraction mechanism 3 at the connection point, the inner spline 6 and the outer spline 9 mesh to ensure stable torque transmission. The shear pin 7 is inserted into the slot 10 to restrict the relative sliding between the drive shaft 1 and the driven shaft 2, thereby maintaining the overall rigidity of the shaft. When the axial force generated by the collision reaches the threshold, the shear pin 7 breaks at the shear groove 8, allowing the drive shaft 1 and the driven shaft 2 to retract relative to each other along the spline. The gear 4 at the end of the driven shaft 2 away from the drive shaft 1 transmits power to the steering system. In the oil filling mechanism 5 inside, the oil reservoir 14 stores lubricating oil, and the oil filling pipe 13 is used to replenish the lubricating oil to the oil reservoir 14. The sealing ring 15 inside the oil filling pipe 13 enhances the sealing performance. The threaded cover 17 closes the oil filling pipe 13 through the threaded engagement with the threaded groove 16, and the threaded cover 17 abuts against... The sealing ring 15 further strengthens the seal to prevent grease leakage and impurities from entering the oil storage area 14; the oil outlet groove 21 on the side wall of the oil storage area 14 provides a flow channel for grease, and the limiting ring 18 restricts the sliding range of the oil outlet pipe 19 and the spring 20. One end of the spring 20 is connected to the limiting ring 18 and the other end is connected to the oil outlet pipe 19. Under normal conditions, the spring 20 pushes the oil outlet pipe 19 to fit against the inner wall of the oil outlet groove 21 to block the grease from flowing out. When lubrication is required, the grease pushes the oil outlet pipe 19 and compresses the spring 20 under slight pressure, and the grease flows out from the gap between the oil outlet pipe 19 and the oil outlet groove 21 to the part that needs lubrication; at the same time, the dust cover 11 outside the connection between the drive shaft 1 and the driven shaft 2 covers the connection part, and the sealing rubber sleeves 12 on the top and bottom inner walls of the dust cover 11 abut against the outer walls of the drive shaft 1 and the driven shaft 2, respectively, to prevent external dust, water vapor and other substances from entering the spline mating surface or the passive contraction mechanism 3, and ultimately ensure smooth overall transmission.

[0026] Finally, it should be noted that the above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Although the present utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A steering input shaft in an electric power steering system for automobiles, comprising a drive shaft (1), characterized in that: One end of the drive shaft (1) is fixedly connected to the car steering wheel, and the other end of the drive shaft (1) is internally slidably connected to the driven shaft (2). A passive retraction mechanism (3) is provided at the connection between the drive shaft (1) and the driven shaft (2). A gear (4) is fixedly connected to the end of the driven shaft (2) away from the drive shaft (1). An oil injection mechanism (5) is provided inside the driven shaft (2). The passive retraction mechanism (3) includes an internal spline (6), which is formed on the bottom inner wall of the drive shaft (1). Four shear pins (7) are fixedly connected to the inner wall of the drive shaft (1). Shear pins (7) have shear grooves (8) on their outer sides. An external spline (9) is fixedly connected to the outer wall of the driven shaft (2). Four slots (10) are formed at the top of the driven shaft (2). The shear pins (7) and slots (10) are matched. The internal spline (6) and external spline (9) are engaged.

2. The steering input shaft in an automotive electric power steering system according to claim 1, characterized in that: The oil injection mechanism (5) includes an oil storage area (14), which is located inside the gear (4). An oil injection pipe (13) is provided on the top wall of the oil storage area (14), and an oil outlet groove (21) is provided on the side wall of the oil storage area (14). A limit ring (18) is fixedly connected to the inner wall of the oil outlet groove (21), and an oil outlet pipe (19) is slidably connected to the inner wall of the oil outlet groove (21). A spring (20) is provided inside the oil outlet groove (21).

3. The steering input shaft in an automotive electric power steering system according to claim 2, characterized in that: The oil injection pipe (13) is fixedly connected to a sealing ring (15), and the inner wall of the oil injection pipe (13) is provided with a threaded groove (16), and the inner wall of the threaded groove (16) is threadedly connected with a threaded cap (17).

4. The steering input shaft in an automotive electric power steering system according to claim 2, characterized in that: One end of the spring (20) is fixedly connected to the outer wall of the limiting ring (18), and the other end of the spring (20) is fixedly connected to the outer wall of the oil outlet pipe (19).

5. The steering input shaft in an automotive electric power steering system according to claim 2, characterized in that: The oil outlet pipe (19) abuts against the inner wall of the oil outlet groove (21).

6. The steering input shaft in an automotive electric power steering system according to claim 3, characterized in that: The threaded cap (17) abuts against the outer wall of the sealing ring (15).

7. The steering input shaft in an automotive electric power steering system according to claim 1, characterized in that: A dust cover (11) is provided on the outside of the connection between the drive shaft (1) and the driven shaft (2). A sealing sleeve (12) is fixedly connected to the top and bottom inner walls of the dust cover (11). The sealing sleeve (12) abuts against the outer walls of the drive shaft (1) and the driven shaft (2) respectively.

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