A limit shear mechanism of a steering column

Abstract

The utility model relates to a limiting shearing mechanism, concretely relates to a limiting shearing mechanism of steering column. The limiting shearing mechanism includes upper column pipe, lower column pipe and shearing pin, and the shearing pin on the lower column pipe is slidably connected with the guide sliding hole of the upper column pipe, the shearing pin is composed of pin body and aluminium mandrel. The shearing pin used in the limiting shearing mechanism can effectively reduce the production cost of the steering column. It can reduce the shearing force, thereby reducing the impact on the human body, protecting the human body, and it is not easy to be broken in the process of adjusting the steering column. At the same time, it can effectively improve the NVH of the steering column. The problem of large shearing force and high production cost of the existing steering column is solved.

Description

Technical Field

[0001] This utility model relates to a limiting shearing mechanism, specifically a limiting shearing mechanism for a steering column. Background Technology

[0002] The steering column is the intermediate component connecting the steering wheel to the lower part of the car's cab. It functions to collapse downwards when the car is impacted, thereby reducing the force exerted by the steering wheel on the driver and thus minimizing injury. Patent application CN214823572U discloses a mechanical steering column, which includes an upper column, a lower column, an upper steering tube, a steering shaft, a locking mechanism, and a support seat. The upper part of the upper column is connected to the lower column via a guide slider, and the lower part of the upper column is connected to the lower column via a locking mechanism. The locking mechanism includes a shear pin, a connecting rod, a connecting seat, a guide plate, a locking cam A, a locking cam B, and an adjusting handle.

[0003] The aforementioned steering column can achieve crumple zone energy absorption via shear pins. However, these shear pins are made entirely of metal (usually aluminum), which not only results in excessive shear force but also in high cost. Excessive shear force leads to a greater impact from the steering wheel to the driver during crumple zone energy absorption, causing more impact on the driver. Using plastic shear pins can effectively reduce cost and shear force, but plastic shear pins have insufficient shear force resistance. Furthermore, plastic is prone to aging and is susceptible to breakage under alternating loads during repeated steering column adjustments over long-term use. Therefore, it is necessary to design a limiting shear mechanism for the steering column to address these issues. Summary of the Invention

[0004] The purpose of this invention is to provide a limiting shearing mechanism for a steering column that can reduce shearing force and effectively lower costs.

[0005] The technical solution of this utility model is: A limiting shearing mechanism for a steering column includes an upper column tube, a lower column tube, and a shearing pin. The upper column tube has an elongated guide slide hole at its top. The lower column tube above the guide slide hole has an assembly hole, in which the shearing pin is inserted. The bottom end of the shearing pin is slidably connected to the guide slide hole. The shearing pin consists of a pin body made of plastic and an aluminum mandrel disposed in the pin body.

[0006] The shear pin has an outer flange at its top end and an inner flange at the bottom of the mounting hole, which abuts against the outer flange. A fixing screw is threaded into the mounting hole above the shear pin, and the fixing screw abuts against the shear pin.

[0007] The bottom cross-section of the shear pin below the outer flange is rectangular, and the long side of the bottom of the shear pin is slidably connected to the guide hole.

[0008] The aluminum mandrel has mounting holes at its bottom.

[0009] The beneficial effects of this utility model are as follows: The limiting shearing mechanism of this steering column combines the functions of the existing steering column shearing pin and guide slider with a shearing pin. This shearing pin can both shear and break, providing protection, and simultaneously guide and limit the relative sliding of the upper and lower column tubes. Because the shearing pin replaces the original shearing pin and guide slider, and uses a plastic-aluminum composite material, it reduces the amount of aluminum used, effectively lowering the production cost of the steering column. Since the shearing pin uses a plastic-aluminum composite material, it can withstand less shearing force than an all-aluminum shearing pin, but more than an all-plastic shearing pin. This reduces shearing force, thus minimizing impact on the driver and protecting them; it also makes it less prone to breakage during steering column adjustments. Furthermore, the plastic exterior of the shearing pin reduces noise during collisions with the upper column tube, effectively improving the NVH (noise, vibration, and harshness) of the steering column. This solves the problems of high shearing force and high production cost associated with existing steering columns. Attached Figure Description

[0010] Figure 1 This is a schematic diagram of the structure of this utility model; Figure 2 This is a schematic diagram of the upper column tube of this utility model; Figure 3 This is a schematic diagram of the lower column tube of this utility model; Figure 4 This is an isometric schematic diagram of the shear pin of this utility model; Figure 5 This is a cross-sectional schematic diagram of the shear pin of this utility model; Figure 6 This is a force curve diagram of the shearing test of the shearing pin of this utility model; Figure 7 It is a force curve diagram of the shearing test of the all-plastic shear pin.

[0011] In the diagram: 1. Upper column tube, 2. Lower column tube, 3. Guide slide hole, 4. Assembly hole, 5. Pin body, 6. Aluminum mandrel, 7. Outer flange, 8. Inner flange, 9. Fixing screw, 10. Mounting hole. Detailed Implementation

[0012] The limiting and shearing mechanism of this steering column includes an upper column tube 1, a lower column tube 2, and a shearing pin. The top of the upper column tube 1 has an elongated guide hole 3. Above the guide hole 3, the lower column tube 2 has an assembly hole 4, into which the shearing pin is inserted. The bottom end of the shearing pin is slidably connected to the guide hole 3. The shearing pin functions by limiting the relative sliding of the upper column tube 1 and the lower column tube 2 through the relative sliding between the shearing pin and the guide hole 3; simultaneously, the shearing action of the guide hole 3 on the shearing pin causes the upper column tube 1 to collapse relative to the lower column tube 2, thereby causing the steering wheel connected to the upper column tube 1 to collapse, thus protecting the occupant through the collapse of the steering wheel. Because this shearing pin has both guiding and shearing / collapse functions, it can replace the existing steering column's guide slider and shearing pin, effectively reducing the production cost of the steering column by simplifying the structure.

[0013] The shear pin consists of a plastic pin body 5 and an aluminum mandrel 6 housed within the pin body 5. The shear pin is manufactured by extrusion molding onto the aluminum mandrel 6. Its shear force resistance falls between that of an all-plastic shear pin of the same specifications and shape and an all-aluminum shear pin. This allows it to withstand the impact forces during steering column adjustment, preventing breakage, while also reducing shear force, thus minimizing crumple zone and potential injury. Furthermore, the reduced aluminum usage compared to an all-aluminum shear pin further lowers production costs. Additionally, the collision between the plastic pin body 5 and the aluminum upper column tube 1, compared to the metal-to-metal collision between the aluminum shear pin and the upper column tube 1, effectively reduces noise during the collision, thereby improving the NVH (noise, vibration, and harshness) of the steering column.

[0014] For safety reasons, a shearing test was conducted on the shear pin. The test results are shown in the table below and attached. Figure 6-7 :

[0015] In the table above, numbers 1-3 represent the experimental data for the shear pins of this application, and numbers 4-6 represent the experimental data for the all-plastic shear pins. From the above data and force curves, it can be seen that the maximum shear force borne by the shear pins of this application is significantly greater than that of the all-plastic shear pins.

[0016] The top end of the shear pin is provided with an outer flange 7, and the bottom of the mounting hole 4 is provided with an inner flange 8. The inner flange 8 and the outer flange 7 are connected to each other to restrict the position of the shear pin and maintain the connection between the shear pin and the lower column tube 2. A fixing screw 9 is threaded into the mounting hole 4 above the shear pin. The fixing screw 9 is connected to the shear pin to press and fix the shear pin in the lower column tube 2. At the same time, the fixing screw 9 can be used to replace the shear pin, thus facilitating maintenance.

[0017] The bottom cross-section of the shear pin below the outer flange 7 is rectangular, and the long side of the bottom of the shear pin is slidably connected to the guide hole 3. By shearing the guide hole 3 with the short side of the bottom of the shear pin, the guide hole 3 is sheared along the long side of the bottom of the shear pin. The increased length of the long side of the shear pin strengthens its ability to resist shearing force and improves the shearing force.

[0018] The aluminum mandrel 6 has a mounting hole 10 at its bottom, through which the aluminum mandrel 6 is fixed on the extruder, thereby forming the pin body 5 by extrusion on the aluminum mandrel 6, thus producing the shear pin.

[0019] The limiting shearing mechanism of this steering column combines the functions of the existing steering column shearing pin and guide slider with a shearing pin. This shearing pin not only provides protection by shearing and breaking, but also guides and limits the relative sliding of the upper and lower column tubes. Because the shearing pin replaces the original shearing pin and guide slider, and uses a plastic-aluminum composite material, it reduces the amount of aluminum used, effectively lowering the production cost of the steering column. Since the shearing pin uses a plastic-aluminum composite material, it can withstand less shearing force than an all-aluminum shearing pin, but more than an all-plastic shearing pin. This reduces shearing force, thus minimizing impact on the user and protecting them; it also makes it less prone to breakage during steering column adjustments. Furthermore, the plastic exterior of the shearing pin reduces noise during collisions with the upper column tube, effectively improving the NVH (noise, vibration, and harshness) of the steering column. This solves the problems of high shearing force and high production cost associated with existing steering columns.

Claims

1. A limiting shearing mechanism for a steering column, comprising an upper column tube (1), a lower column tube (2), and a shearing pin, wherein the top of the upper column tube (1) is provided with an elongated guide sliding hole (3), characterized in that: An assembly hole (4) is provided on the lower column tube (2) above the guide slide hole (3). A shear pin is inserted into the assembly hole (4). The bottom end of the shear pin is slidably connected to the guide slide hole (3). The shear pin is composed of a plastic pin body (5) and an aluminum mandrel (6) set in the pin body (5).

2. The limiting shearing mechanism for a steering column according to claim 1, characterized in that: The top end of the shear pin is provided with an outer flange (7), and the bottom of the assembly hole (4) is provided with an inner flange (8). The inner flange (8) and the outer flange (7) are abutted together. A fixing screw (9) is threaded in the assembly hole (4) above the shear pin. The fixing screw (9) is abutted together with the shear pin.

3. The limiting shearing mechanism for a steering column according to claim 2, characterized in that: The bottom cross-section of the shear pin below the outer flange (7) is rectangular, and the long side of the bottom of the shear pin is slidably connected to the guide slide hole (3).

4. The limiting shearing mechanism for a steering column according to claim 1, characterized in that: The aluminum mandrel (6) has a mounting hole (10) at its bottom.

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