Steering column with controllable collapse force

Abstract

The application discloses a collapsible steering column with controllable collapsing force, which comprises a column tube mechanism, a rotating shaft mechanism, a support mechanism, a handle mechanism, an axial soft limit, a rivet, a long bolt and a rolling cam. The handle mechanism provides a preset tightening torque for the long bolt. When the steering column collapses, the tightening torque provides a collapsing friction force between the upper column tube and the lower column tube. The resultant force of the collapsing friction force and the shearing force of the rivet provides a collapsing peak force. The resultant force of the collapsing friction force and the friction force between the rolling cam and the upper column tube provides a collapsing sustained force. By adjusting the preset collapsing friction force, the collapsing peak force and the collapsing sustained force, the collapsing force of the steering column can be controlled. The collapsible steering column with controllable collapsing force can effectively reduce the cost of the collapsing mechanism of the steering column, shorten the development cycle of the steering column, and accurately control the collapsing force of the collapsing stroke of the column. The application provides great reference value for cost control and safety improvement of the steering column.

Description

Technical Field

[0001] This invention relates to the field of automotive steering system technology, and in particular to a steering column with controllable collapsibility force. Background Technology

[0002] Vehicle safety is one of the three major themes for the sustainable development of the automotive industry. Active and passive safety features are particularly important in the production and research and development of automobiles. According to the latest traffic accident statistics and automotive crash test results, in a frontal collision, the steering mechanism is the primary component causing driver injury, and the crumple zone of the steering column is the most critical component in preventing driver injury. Therefore, developing a steering column with good safety performance and controllable crumple force is of paramount importance, and finding a method to control the crumple force is the core of achieving controllable crumple force. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to provide a steering column with low cost, good safety performance and controllable collapsibility force.

[0004] To solve the above-mentioned technical problems, the present invention provides a steering column with controllable collapsibility force, including a column tube mechanism, a rotating shaft mechanism, a support mechanism, a handle mechanism, an axial soft limiter, rivets, long bolts, and a rolling cam;

[0005] The top of the rotating shaft mechanism is connected to the steering wheel and is connected to the column tube mechanism through a bearing; the upper part of the bracket mechanism is connected to the protective cover and is connected to the column tube mechanism and the handle mechanism through long bolts; the axial soft limit is connected to the column tube mechanism by rivets.

[0006] The column tube mechanism consists of an upper column tube and a lower column tube; the upper column tube is connected to the rotating shaft mechanism and can move axially in the lower column tube; the lower column tube is connected to the handle mechanism and the support mechanism, and its end is connected to the whole vehicle.

[0007] The handle mechanism provides a preset tightening torque to the long bolt. When the steering column collapses, the tightening torque provides a collapse friction force between the upper and lower column tubes. The resultant force of the collapse friction force and the shearing force of the rivet provides the peak collapse force. The resultant force of the collapse friction force and the friction force between the rolling cam and the upper column tube provides the sustained collapse force.

[0008] By adjusting the preset collapsible friction, peak collapsible force, and sustained collapsible force, the collapsible force of the steering column can be controlled.

[0009] Preferably, the axial soft stop is connected to the upper column tube by a rivet; when the steering column collapses, the upper column tube drives the axial soft stop to move axially until it collides with the lower column tube. When the accumulated stress is greater than the peak collapse force, the rivet is sheared off.

[0010] Preferably, the rolling cam is mounted on a long bolt, and the upper column tube has an open slot; when the steering column collapses, the rolling cam slides in the open slot of the upper column tube. After the rivet is sheared, the rolling cam slides onto the upper column tube. There is a preset interference fit between the rolling cam and the upper column tube. The resultant force of the collapse friction and the friction between the rolling cam and the upper column tube provides the collapse persistence force.

[0011] Preferably, the rolling cam is made of steel with a layer of rubber attached to its surface.

[0012] Preferably, the formula for calculating the adjustment of the collapsing friction force is: Where F1 is the collapsing friction force, μ is the friction coefficient between the upper and lower cylindrical tubes, K1 is the clamping efficiency, K0 is the tightening force coefficient, and T is the tightening torque of the handle mechanism.

[0013] Preferably, the formula for calculating the peak collapsing force is: F2=F1+0.85n×σ×A, where F2 is the peak collapsing force, n is the number of rivets, σ ​​is the tensile strength of the rivets, and A is the shear area.

[0014] Preferably, the formula for calculating the adjustment of the crumple persistence is: Where F3 is the collapse sustaining force, μ1 is the friction coefficient between the upper cylindrical tube and the rolling cam, E is the elastic modulus of the roller, D is the thickness of the upper cylindrical tube, l is the interference between the rolling cam and the upper cylindrical tube, R1 is the radius of the roller, and R2 is the radius of the upper cylindrical tube.

[0015] Compared with existing technologies, the controllable collapsible force steering column provided by this invention can effectively reduce the cost of the steering column collapsible mechanism, shorten the steering column development cycle, and accurately control the collapsible force during the collapsible stroke of the column, providing great reference value for cost control and safety improvement of the steering column. Attached Figure Description

[0016] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments:

[0017] Figure 1 A detailed exploded view of the collapsible force controllable steering column provided in an embodiment of the present invention;

[0018] Figure 2 A schematic diagram of the assembled steering column with controllable collapsibility force according to an embodiment of the present invention;

[0019] Figure 3 An exploded view of the controllable collapsibility steering column mechanism provided in an embodiment of the present invention.

[0020] Explanation of reference numerals in the attached figures

[0021] 1-Column tube mechanism, 2-Rotating shaft mechanism, 3-Bracket mechanism, 4-Handle mechanism, 5-Axial soft limit, 6-Rivet, 7-Long bolt, 8-Rolling cam. Detailed Implementation

[0022] The following specific embodiments illustrate the implementation of the present invention. Those skilled in the art can fully understand other advantages and technical effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through different specific embodiments, and the details in this specification can also be applied based on different viewpoints, with various modifications or changes made without departing from the overall design concept of the invention. It should be noted that, in the absence of conflict, the following embodiments and features in the embodiments can be combined with each other. The following exemplary embodiments of the present invention can be implemented in many different forms and should not be construed as being limited to the specific embodiments set forth herein. It should be understood that these embodiments are provided to make the disclosure of the present invention thorough and complete, and to fully convey the technical solutions of these exemplary embodiments to those skilled in the art.

[0023] like Figures 1 to 3 As shown, this specific embodiment provides a steering column with controllable collapsibility force, including a column tube mechanism 1, a rotating shaft mechanism 2, a bracket mechanism 3, a handle mechanism 4, an axial soft limit 5, a rivet 6, a long bolt 7, and a rolling cam 8.

[0024] The top of the rotating shaft mechanism 2 is connected to the steering wheel and is connected to the column tube mechanism 1 through a bearing; the upper part of the bracket mechanism 3 is connected to the protective cover and is connected to the column tube mechanism 1 and the handle mechanism 4 through a long bolt 7; the axial soft limit 5 is connected to the column tube mechanism 1 through a rivet 6.

[0025] The column tube mechanism 1 consists of an upper column tube and a lower column tube; the upper column tube is connected to the rotating shaft mechanism 2 and can move axially in the lower column tube; the lower column tube is connected to the handle mechanism 4 and the bracket mechanism 3, and its end is connected to the whole vehicle.

[0026] The handle mechanism 4 provides a preset tightening torque to the long bolt 4. When the steering column collapses, the tightening torque generates a clamping force on the upper and lower column tubes, providing a collapse friction force between the upper and lower column tubes. The resultant force of the collapse friction force and the shearing force of the rivet provides the peak collapse force, and the resultant force of the collapse friction force and the friction force between the rolling cam and the upper column tube provides the continuous collapse force.

[0027] By adjusting the preset collapsible friction, peak collapsible force, and sustained collapsible force, the collapsible force of the steering column can be controlled.

[0028] In this specific embodiment, the axial soft stop 5 is connected to the upper column tube by a rivet 6. When the steering column collapses, the upper column tube drives the axial soft stop 5 to move axially until it collides with the lower column tube. When the accumulated stress exceeds the peak collapse force, the rivet 6 is sheared off. Alternatively, the axial soft stop 5 can also be connected to the lower column tube by a rivet 6.

[0029] The rolling cam 8 is mounted on the long bolt 7, and the upper column tube has an open slot. When the steering column collapses, the rolling cam 8 slides within the open slot of the upper column tube. After the rivet 6 is sheared, the rolling cam 8 slides onto the upper column tube. There is a preset interference fit between the rolling cam 8 and the upper column tube. The combined force of the collapse friction and the friction between the rolling cam and the upper column tube provides the collapse sustaining force. The rolling cam 8 is made of steel with a thin layer of rubber attached to its surface, which effectively prevents damage and noise between the rolling cam 8 and the upper column tube.

[0030] When the steering column collapses, the collapse force is mainly controlled by the collapse friction force in the early stage of collapse. After the collapse begins, the axial soft limit collision with the lower column tube changes the collapse force to be mainly controlled by the peak collapse force. After the rivet is sheared, the rolling cam 8 moves onto the upper column tube, at which point the collapse force is controlled by the sustained collapse force.

[0031] The collapsing friction force can be controlled by the tightening torque of the handle mechanism: Where K0 is the tightening force coefficient, typically taken as 0.25; d is the nominal thread diameter; and F0 is the preload. The formula for calculating the collapsible friction force is: Where μ is the coefficient of friction between the cylindrical tubes, typically taken as 0.2, K1 is the clamping efficiency, typically taken as 0.7, and T is the tightening torque of the handle mechanism. Therefore, the collapsing friction force...

[0032] The peak collapse force can be controlled by the rivet type and quantity: the tensile strength σ of different rivet types is known, the shear strength τ of the rivet is 0.8 × σ, and the shear force F borne by the rivet under shear conditions is... q =τ×A, where A is the shear area of ​​the rivet. Therefore, the peak collapse force F2 = F1 + 0.85n×σ×A, where n is the number of rivets;

[0033] The collapse persistence force is controlled by the size of the rolling cam. Since the rubber coating is in a crushed state during rolling, its viscous energy dissipation and thickness are negligible. Therefore, the collapse persistence force F3 is equivalent to the rolling friction force f between the roller and the upper cylindrical tube. At this time, according to Hertz contact theory, when a cylinder with radius R1 and a cylinder with radius R2 are in elastic orthogonal contact, their contact area can be simplified to Ax. 2 +By 2 =C rectangle, Contact stress Simultaneously, the contact stress can be calculated using Hooke's Law: Where P is the normal force, E is the elastic modulus, D is the thickness of the upper cylindrical tube, and l is the interference fit between the rolling cam and the upper cylindrical tube. The normal force acting on the rolling cam... Therefore, the collapse persistence can be expressed as μ1 is the coefficient of friction between the upper cylindrical tube and the rolling cam.

[0034] In summary, the collapse force in the early stage of collapse is The mid-stage collapse force is The collapse force in the later stage of collapse is

[0035] The controllable collapsible force steering column provided by this invention can effectively reduce the cost of the steering column collapsible mechanism, shorten the steering column development cycle, and accurately control the collapsible force during the collapsible stroke of the column, providing great reference value for cost control and safety improvement of the steering column.

[0036] The present invention has been described in detail above through specific embodiments and examples, but these are not intended to limit the invention. Many modifications and improvements can be made by those skilled in the art without departing from the principles of the invention, and these should also be considered within the scope of protection of the present invention.

Claims

1. A steering column with controllable collapsibility force, characterized in that, It includes a column tube mechanism, a rotating shaft mechanism, a support mechanism, a handle mechanism, an axial soft limit, rivets, long bolts, and a rolling cam; The top of the rotating shaft mechanism is connected to the steering wheel and is connected to the column tube mechanism through a bearing; the upper part of the bracket mechanism is connected to the protective cover and is connected to the column tube mechanism and the handle mechanism through long bolts; the axial soft limit is connected to the column tube mechanism by rivets. The column tube mechanism consists of an upper column tube and a lower column tube; the upper column tube is connected to the rotating shaft mechanism and can move axially in the lower column tube; the lower column tube is connected to the handle mechanism and the support mechanism, and its end is connected to the whole vehicle. The handle mechanism provides a preset tightening torque to the long bolt. When the steering column collapses, the tightening torque provides a collapse friction force between the upper and lower column tubes. The resultant force of the collapse friction force and the shearing force of the rivet provides the peak collapse force. The resultant force of the collapse friction force and the friction force between the rolling cam and the upper column tube provides the sustained collapse force. By adjusting the preset collapsible friction force, collapsible peak force, and collapsible duration force, the collapsible force of the steering column can be controlled. The axial soft limiter is connected to the upper column tube by a rivet; when the steering column collapses, the upper column tube drives the axial soft limiter to move axially until it collides with the lower column tube. When the accumulated stress is greater than the peak collapse force, the rivet is sheared off. The rolling cam is mounted on a long bolt, and the upper column tube has an open slot. When the steering column collapses, the rolling cam slides in the open slot of the upper column tube. After the rivet is sheared, the rolling cam slides onto the upper column tube. There is a preset interference fit between the rolling cam and the upper column tube. The resultant force of the collapse friction and the friction between the rolling cam and the upper column tube provides the collapse continuous force.

2. The controllable collapsibility steering column according to claim 1, characterized in that, The rolling cam is made of steel with a layer of rubber attached to its surface.

3. The controllable collapsibility steering column according to claim 1, characterized in that, The formula for calculating the collapsible friction force is: ,in The friction force is the collapsing friction, and µ is the coefficient of friction between the upper and lower cylindrical tubes. For clamping efficiency, It is the tightening force coefficient. d is the tightening torque of the handle mechanism, and d is the nominal diameter of the thread.

4. The controllable collapsibility steering column according to claim 3, characterized in that, The friction coefficient µ between the upper and lower column tubes is taken as 0.

2.

5. The controllable collapsibility steering column according to claim 3, characterized in that, Clamping efficiency Take 0.

7.

6. The controllable collapsibility steering column according to claim 3, characterized in that, Tightening force coefficient Take 0.

25.

7. The controllable collapsibility steering column according to claim 3, characterized in that, The formula for calculating the peak collapse force is: ,in Where n is the peak collapsing force, and n is the number of rivets. The tensile strength of the rivet. This represents the area of ​​the shear surface.

8. The crumple zone controllable steering column according to claim 3, characterized in that, The formula for calculating the collapse sustaining force is: ,in For collapse persistence, R is the coefficient of friction between the upper cylindrical tube and the rolling cam, E is the elastic modulus of the roller, D is the thickness of the upper cylindrical tube, l is the interference between the rolling cam and the upper cylindrical tube, R1 is the radius of the roller, and R2 is the radius of the upper cylindrical tube.

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