Steering column assembly and steering shaft anti-rotation separation device thereof

Abstract

A steering column assembly has a tubular jacket assembly defining a bore extending along a central axis between a jacket lower end and a jacket upper end; and a steering shaft assembly extending through the bore along the central axis between a steering shaft lower end and a steering shaft upper end. A separation device extends between the tubular sheath assembly and the steering shaft assembly. The disengagement device has a first state in which the steering shaft assembly is prevented from rotating relative to the tubular sheath assembly and a second state in which the steering shaft assembly is free to rotate relative to the tubular sheath assembly. The separation device is provided with at least one fragile piece, the fragile piece has an unbroken state and a broken state, in the unbroken state, the separation device is in the first state, and in the broken state, the separation device is in the second state.

Description

Technical Field

[0001] The following description generally relates to the steering column assembly, and more specifically to an anti-rotation device for preventing rotation between the steering shaft and the outer sheath during assembly. Background Technology

[0002] Vehicles typically have a steering column assembly that includes a central steering shaft positioned through the outer casing. To facilitate steering column assembly, the outer casing (sometimes referred to as a housing, sleeve, or tube) and the steering shaft are typically positioned relative to each other in a predetermined rotational orientation (hereinafter referred to as the neutral orientation) and prevented from moving therefrom during assembly, such that the steering shaft can be attached to its corresponding component (such as a steering gear), and the outer sleeve can be attached to its corresponding component (such as a fixed frame member of the vehicle body). Thus, upon completion of assembly, the outer sleeve and the steering shaft are properly oriented in the neutral position relative to each other.

[0003] A known mechanism for holding the steering shaft and outer sleeve in a neutral position involves inserting a metal pin through a pair of radially opposing through-holes in the outer sleeve (called sleeve openings) and a pair of radially opposing through-holes in the steering shaft (called shaft openings), thereby locking the steering shaft and outer sleeve in a neutral position to prevent rotation relative to each other. Then, during the final assembly of the steering column assembly, the steel pin is pulled outward from the shaft openings and sleeve openings. While this generally effectively prevents movement of the steering shaft and outer sleeve relative to each other during assembly, some problems can arise.

[0004] For example, the shaft opening and sleeve opening have tolerances, as do the steel pins. Therefore, various fits can occur within the shaft and sleeve openings, including tight fits, line-to-line fits, and loose fits. In the case of a tight fit, removing the steel pin after assembly can be difficult, causing inconvenience to operators and potentially delaying the assembly line. In the case of a loose fit, the desired rotational orientation of the steering shaft relative to the outer sleeve may be affected, resulting in unsatisfactory final assembly. Furthermore, from a machining perspective, forming the shaft and sleeve openings is costly.

[0005] Therefore, it is desirable to provide a device that enables the steering shaft and the outer sheath to be maintained in a neutral position relative to each other during assembly, while at least solving the problems discussed above. Summary of the Invention

[0006] According to an exemplary embodiment of the present disclosure, a steering column assembly is provided. The steering shaft assembly includes: a tubular sheath assembly defining a hole extending along a central axis between a lower end and an upper end of the sheath; and a steering shaft assembly extending along the central axis through the hole between the lower and upper ends of the steering shaft. A separation device extends between the tubular sheath assembly and the steering shaft assembly. The separation device has a first state and a second state, in which rotation of the steering shaft assembly relative to the tubular sheath assembly is prevented, and in the second state, free rotation of the steering shaft assembly relative to the tubular sheath assembly is achieved. The separation device has at least one fragile fragment having an unbroken state and a broken state, in which the separation device is in the first state and in the broken state, the separation device is in the second state.

[0007] In another exemplary embodiment of the invention, a steering shaft anti-rotation separation device for a steering column assembly is provided, the steering column assembly having a tubular sheath assembly and a steering shaft assembly extending therethrough. The steering shaft anti-rotation separation device has an outer member configured to be fixed to prevent rotation with the tubular sheath assembly and an inner member configured to be fixed to prevent rotation with the steering shaft assembly. At least one fragile component, in an unbroken state, engages the outer member with the inner member to maintain the anti-rotation separation device as a single integral material piece, wherein the outer member and the inner member are fixed to prevent movement relative to each other. In a broken state, the at least one fragile component disengages the outer member from the inner member, in which the single integral material piece is converted into a separable material piece, wherein the outer member and the inner member are capable of movement relative to each other.

[0008] In another exemplary embodiment of the invention, a method for assembling a steering column assembly is provided. The method includes: providing a tubular sheath assembly defining a hole extending along a central axis between a lower end and an upper end of the sheath; and distributing a steering shaft assembly through the hole along the central axis. Furthermore, in a first state, a disconnect device is coupled to the tubular sheath assembly and the steering shaft assembly to prevent the steering shaft from rotating relative to the tubular sheath assembly. The steering column assembly is then attached to the body of the motor vehicle, and further, a torque is applied to the steering shaft assembly to transition the disconnect device to a second state in which the steering shaft assembly can rotate freely relative to the tubular sheath assembly.

[0009] These and other advantages and features will become apparent to those skilled in the art from the following description taken in conjunction with the accompanying drawings. Attached Figure Description

[0010] The subject matter considered to be the invention is specifically pointed out and explicitly claimed in the claims at the end of this specification. The foregoing and other features and advantages of the invention will become apparent from the following detailed description taken in conjunction with the accompanying drawings, in which:

[0011] Figure 1 This is a perspective view of a steering column assembly for a motor vehicle having a steering shaft anti-rotation separation device according to an embodiment of the present disclosure;

[0012] Figure 2A It is observed roughly along arrow 2A. Figure 1 End view of the steering column assembly;

[0013] Figure 2B yes Figure 2A An enlarged partial view of the steering column assembly, which better shows the steering shaft anti-rotation separator, wherein the fragile parts of the steering shaft anti-rotation separator are shown as being in an unbroken state;

[0014] Figure 2C It is similar to Figure 2B The view shows the fragility of the steering shaft anti-rotation separation device, which is shown to be in a broken state;

[0015] Figure 3A It is roughly along Figure 1 A cross-sectional view taken from line 3A-3A;

[0016] Figure 3B yes Figure 3A A magnified partial view of the surrounding region 3B;

[0017] Figure 4 This is a perspective rear view of a steering shaft anti-rotation separator, which is shown with the steering shaft configured to pass through an opening in the steering shaft anti-rotation separator.

[0018] Figure 5 yes Figure 4 A partial front view;

[0019] Figure 6 yes Figure 4 The side view shows the vertical plane mounting surface of the steering sleeve assembly and the arc-shaped deflection curve of the steering shaft anti-rotation separator when the steering shaft anti-rotation separator is fixed to the mounting surface;

[0020] Figure 7 It is similar to Figure 6 The view shows a steering shaft anti-rotation separator fixedly mounted to a mounting surface, with the brittle fragments shown in their unbroken state;

[0021] Figure 8It is similar to Figure 7 The view shows the fragility of the steering shaft being rotated relative to the steering column assembly as it is in its broken state.

[0022] Figure 9A It is similar to Figure 4 The view shows a steering shaft anti-rotation separation device according to another embodiment of the present disclosure, wherein the fragile parts of the steering shaft anti-rotation separation device are shown to be in an unbroken state.

[0023] Figure 9B It is similar to Figure 9A The view shows the fragility of the steering shaft anti-rotation separation device in a broken state;

[0024] Figure 10A It is similar to Figure 9A The view shows a steering shaft anti-rotation separation device according to another embodiment of the present disclosure, wherein the fragile parts of the steering shaft anti-rotation separation device are shown in an unbroken state;

[0025] Figure 10B It is similar to Figure 10A The view shows the fragility of the steering shaft anti-rotation separation device in a broken state;

[0026] Figure 11A This is a perspective view of a steering sleeve assembly, wherein a steering shaft is configured to pass through the steering sleeve assembly, the steering sleeve assembly having a steering shaft anti-rotation separation device according to another embodiment of the present disclosure, wherein the fragile parts of the steering shaft anti-rotation separation device are shown in an unbroken state; and

[0027] Figure 11B It is similar to Figure 11A The view shows the easily broken pieces of the anti-rotation separation device of the steering shaft in a broken state. Detailed Implementation

[0028] Referring now to the accompanying drawings, the invention will be described with reference to specific embodiments, but is not intended to limit the invention. Figure 1 , Figure 2A and Figure 3AAn exemplary steering column assembly 10 for a motor vehicle (such as any modern platform passenger vehicle (not shown)) is illustrated. The steering column assembly 10 includes a tubular sheath assembly 12 defining a bore 14 extending along a longitudinal central axis 16 between a lower end 12a and an upper end 12b of the sheath. The steering column assembly 10 also includes a steering shaft assembly 18 extending through the bore 14 along the longitudinal central axis 16 between a lower end 18a and an upper end 18b of the steering shaft. The steering column assembly 10 also includes a steering shaft anti-rotation separator (hereinafter referred to as separator 20) extending between the tubular sheath assembly 12 and the steering shaft assembly 18. The separation device 20 has a first state and a second state. In the first state, the steering shaft assembly 18 is prevented from rotating relative to the tubular sheath assembly 12 about the longitudinal central axis 16, such that the steering shaft assembly 18 and the tubular sheath assembly 12 remain fixed to prevent rotational movement relative to each other. In the second state, the steering shaft assembly 18 can rotate freely relative to the tubular sheath assembly 12 about the longitudinal central axis 16. The separation device 20 has at least one brittle member (also referred to as a fragment 22), wherein the at least one fragment 22 has an unbroken state and a broken state. In the unbroken state, the separation device 20 is in a single-piece integral first state, and in the broken state, the separation device 20 is in a separated component second state. When in a first state, the release device 20 is used to maintain the desired rotational position of the steering shaft assembly 18 relative to the tubular sheath assembly 12 during the assembly of the steering column assembly 10 into the motor vehicle, thereby facilitating the rotational centering of the steering wheel (also referred to as the steering wheel (not shown)). After assembly, as discussed further below, the release device 20 can be switched to a second state to allow the steering shaft assembly 18 to rotate freely and unrestricted relative to the tubular sheath assembly 12 during the use and steering of the motor vehicle.

[0029] The steering shaft assembly 18 is supported by a plurality of bearings for rotation about a longitudinal central axis 16 within bore 14. These bearings are shown as a lower bearing (by way of example and not limitation, such as a lower roller bearing 24a) and an upper bearing (by way of example and not limitation, such as an upper roller bearing 24b). The lower bearing 24a is shown fixed adjacent to the lower end 12a of the tubular sheath, while the upper bearing 24b is shown fixed adjacent to the upper end 12b of the tubular sheath. The steering shaft assembly 18 can be configured as a single integral piece, or, as shown, have a plurality of pieces fixed to each other. Figure 3AThe steering shafts 18 and 10 are shown as lower steering shaft 26a and upper steering shaft 26b. As discussed further below, the separation device 20 can be fixed adjacent to the lower end 12a of the tubular sheath assembly to serve both as a steering shaft anti-rotation separation device to prevent the steering shaft assembly 18 from rotating during the assembly of the steering column assembly 10 into the motor vehicle, and as a bearing retainer cover to hold the lower bearing 24a in a desired axial position relative to the longitudinal central axis 16 within the bore 14 of the tubular sheath assembly 12, and further to shield the lower bearing 24a to prevent the entry of contaminants. Thus, the separation device 20 is multifunctional, and after the assembly of the steering column assembly 10 into the motor vehicle is completed, the separation device 20 can be switched to its second state, in which the steering shaft assembly 18 rotates freely about the longitudinal central axis 16 when the motor vehicle is steered in use, while the tubular sheath assembly 12 remains attached to the main frame member of the vehicle (not shown) to prevent relative movement thereto.

[0030] According to one embodiment of this disclosure, such as Figure 2B , Figure 2C , Figure 3B and Figures 4 to 8As shown, the separation device 20 has an outer portion (also referred to as outer member 28a) and an inner portion (also referred to as inner member 28b). The outer portion is fixed to prevent rotation with the tubular sheath assembly 12, and the inner portion is fixed to prevent rotation with the steering shaft assembly 18. When at least one frag 22 is in an unbroken state, the outer member 28a and the inner member 28b are connected together by at least one frag 22 to prevent relative rotation, thereby maintaining the separation device 20 in a single-piece first state. When at least one frag 22 is transformed into a broken state, the outer member 28a and the inner member 28b disengage from each other, forming a separate component, thereby allowing relative rotation between the outer member 28a and the inner member 28b, thereby placing the separation device 20 in a second state. The outer member 28a has an inner periphery 40, and the inner member 28b has an outer periphery 42, wherein at least one frag 22, in the unbroken state, extends from the inner periphery 40 to the outer periphery 42, thereby connecting the outer member 28a to the inner member 28b in a fixed relationship. At least one frag 22 is shown as a plurality of frag 22 spaced apart from each other around a central axis 16, and in a non-limiting embodiment, as three frag 22 equidistantly spaced from each other around an inner periphery 40 and an outer periphery 42. The frag 22 can be sized and shaped as needed to provide the desired strength and torque required to break the frag 22 after the steering column assembly 10 has been assembled into the motor vehicle. Upon completion of assembly, torque can be applied to the release device 20 by rotating the steering shaft assembly 18 with a torque exceeding the breaking strength of the frag 22, thereby enabling the tab 22 to transition from a first unbroken state to a second broken state. In a non-limiting embodiment, a torque in the range of 50 Nm to 200 Nm, more preferably between 75 Nm and 150 Nm, is contemplated to transition the tab 22 from the first unbroken state to the second broken state.

[0031] like Figure 7As shown, the outer member 28a can be directly secured to the tubular sheath assembly 12 via at least one fastener 30, and is shown as a pair of fasteners 30 in a non-limiting embodiment. To facilitate securing the outer member 28a to the tubular sheath assembly 12, the outer member 28a can be formed having at least one flange, and is formed, by way of example and not limitation, as a pair of radially opposing flanges 31, wherein a fastener opening 33 in each flange 31 is configured to receive a corresponding fastener 30 passing through it. The inner member 28b is secured by an anti-rotation feature 32 to prevent rotation with the steering shaft assembly 18. In a non-limiting embodiment, the anti-rotation feature 32 includes a non-circular through-opening 34 in the inner member 28b and a non-circular outer surface 36 on the steering shaft assembly 18. The non-circular outer surface 36 extends through the non-circular through-opening 34, wherein the shape and size of the corresponding non-circular through-opening 34 and the non-circular outer surface 36 are designed to prevent relative rotation between them. In the non-limiting embodiment shown, the non-circular outer surface 36 and the non-circular through opening 34 mate with each other such that the non-circular outer surface 36 and the non-circular through opening 34 have the same non-circular geometry, wherein the non-circular outer surface 36 has a line-to-line fit, a slight interference fit, or a slight loose fit with the non-circular through opening 34. If a slight loose fit is provided, it should be understood that negligible relative movement is provided between the release device 20 and the steering shaft assembly 18. The non-circular outer surface 36 of the steering shaft assembly 18 is shown extending from the lower end 18a to the shoulder 38, such that during assembly, the inner member 28b of the release device 20 faces the shoulder 38 with which it engages, such that the shoulder 38 serves as a limiting stop surface when the fastener 30 secures the outer member 28a to the mounting surface 44 of the tubular sheath assembly 12. If desired, the shoulder 38 can be configured as an annular, circumferentially continuous shoulder. Shoulder 38 and mounting surface 44 are axially offset relative to each other along central axis 16, such that during assembly of separation device 20, separation device 20 can be biased and elastically flexed, as... Figure 7 As shown.

[0032] like Figure 8 As shown, when the separator 20 is fixed to the steering column assembly 10, and especially when the separator 20 is switched to the second state (where the fragile fragment 22 breaks), Figure 8When the separation device 20 is in the second state, the outer member 28a extends along the first plane P1 and the inner member 28b extends along the second plane P2, wherein the first plane P1 and the second plane P2 extend along the central axis 16 in a relationship of axial spacing from each other and in a relationship of substantially parallel to each other. Therefore, any material on the outer member 28a and / or the inner member 28b that holds the fractured fragility 22 is sufficiently spaced apart from each other, preventing interference between them during rotation of the steering shaft assembly 18, thereby preventing interference and noise generation. When the separation device 20 is in the first state, during initial assembly ( Figure 7 The elastic deflection of the initial bias applied between the outer member 28a and the inner member 28b promotes the elastic deflection after fracture. Figure 8 The material of the fractured fragile fragment 22 is spaced apart. The elastic flexural force with an initial bias applied between the outer member 28a and the inner member 28b allows the material of the fragile fragment 22 to be axially separated from each other upon fracture, achieving a non-biased state, thereby being spaced apart and unable to contact during the use of the steering column assembly 10.

[0033] According to another aspect of this disclosure, Figure 9A A separation device 120 constructed according to another embodiment of the present disclosure is shown. The separation device 120 is used to perform the same function as discussed above for the separation device 20 during the assembly of the steering column assembly into the motor vehicle, namely, maintaining the desired rotational orientation of the steering shaft assembly 118 relative to the tubular sheath assembly (the same as shown for the tubular sheath assembly 12), and then, after the assembly of the steering column assembly is completed, the separation device 120 can be easily transitioned from the first state to the second state.

[0034] The separation device 120 has at least one brittle component (also referred to as a fragment 122), wherein at least one fragment 122 is in an unbroken state. Figure 9A ) and fracture state ( Figure 9B In the unbroken state, the release device 120 is in a first state; in the broken state, the release device 120 is in a second state. In the first state, the release device 120 is used to maintain the desired rotational position of the steering shaft assembly 118 relative to the tubular sheath assembly 12 during the assembly of the steering column assembly 10 into the motor vehicle. After assembly, the release device 120 can be switched to the second state to allow the steering shaft assembly 118 to rotate freely and unrestricted relative to the tubular sheath assembly 12 during the use and steering of the motor vehicle.

[0035] The steering column assembly 118 has an outer surface 136 having at least one groove (shown by way of example and not limitation, as a single groove 46 extending into the outer surface 136), and at least one frag (shown by way of example and not limitation, as a single frag 122) is disposed in the groove 46 in an unbroken state, in which the release device 120 is in a first state. The frag 122 may be configured to have a weak region 48 (e.g., such as by reducing thickness and / or perforation) to facilitate the transition of the frag 122 from an unbroken state to a broken state, in which the release device 120 is in a second state. The release device 120 has a flange 131 as discussed above with respect to flange 31 to facilitate securing the release device 120 to the tubular sheath assembly 12. When completing the assembly of the steering column assembly into the motor vehicle, as Figure 9B As shown, torque can be applied to the separation device 120 by rotating the steering shaft assembly 118 with a torque higher than the fracture strength of the frag 122, thereby enabling the tab 122 to transition from a first unfractured state to a second fractured state. In a non-limiting embodiment, a torque in the range of 50 Nm to 200 Nm, and more preferably between 75 Nm and 150 Nm, is envisioned to transition the tab 122 from the first unfractured state to the second fractured state.

[0036] According to another aspect of this disclosure, Figure 10A A separation device 220 constructed according to another embodiment of this disclosure is shown. Separation device 220 is constructed similarly to separation device 110 and is used to perform the same function discussed above for separation device 20 during the assembly of the steering column assembly into a motor vehicle, namely, maintaining the desired rotational orientation of the steering shaft assembly 218 relative to the tubular sheath assembly (the same as shown for tubular sheath assembly 12), and then, after the assembly of the steering column assembly is completed, separation device 220 can be easily transitioned from a first state to a second state. The separation device is similar to separation device 120; however, the fragile fragment 222 may be configured to have reduced dimensions, including a circumferentially extending width, and may include a weak region 248 (e.g., such as by having notches or opposing notches formed in opposite sides of the fragile fragment 222) to facilitate the fragile fragment 222 remaining in a never-fractured state. Figure 10A ) transforms into a fracture state ( Figure 10B In this fractured state, the separation device 220 is in the second state.

[0037] According to another aspect of this disclosure, Figure 11AA separation device 320 constructed according to another embodiment of the present disclosure is shown. The separation device 320 is used to perform the same function as discussed above for the separation device 20 during the assembly of the steering column assembly into a motor vehicle, namely, maintaining the desired rotational orientation of the steering shaft assembly 318 relative to the tubular sheath assembly 312, and then, after the assembly of the steering column assembly is completed, the separation device 320 can be easily transitioned from a first state corresponding to the unbroken state to a second state corresponding to the broken state.

[0038] The steering shaft assembly 318 has an outer shaft surface 336 with a shaft opening 50 extending therein, and the tubular sleeve assembly 312 has a tubular wall with a sleeve opening 52 extending through it. The separation device 320 has an outer member 328a disposed within the sleeve opening 52 and an inner member 328b disposed within the shaft opening 50, wherein the fragile piece 322, in an unbroken state, connects the outer member 328a to the inner member 328b. With the separator 320 fixed in place, the tubular sheath assembly 312 and the steering shaft assembly 318 are locked to prevent relative rotation, such that the steering shaft assembly 318 is maintained in a desired rotational orientation, such as a neutral orientation where the corresponding wheel of a motor vehicle is in a straight forward orientation and the steering wheel is in a neutral straight steering orientation, wherein the wheel rolls along a straight path (by way of example and not limitation) throughout the assembly of the steering column assembly to the motor vehicle, as in the previously discussed embodiments of separators 18, 118, 218. The internal member 328a can be configured to have a cylindrical or conical shape having a plurality of annular ridges 54, the dimensions of which are set to snap into the shaft opening 50 when pressed into it. When assembling the steering column assembly into the motor vehicle, torque can be applied to the release device 320 by rotating the steering shaft assembly 318 with a torque exceeding the fracture strength of the fragility 322, thereby causing the fragility 322 to transition from a first unfractured state to a second fractured state facilitated by the weak region 348, such as... Figure 11B As shown. In a non-limiting embodiment, a torque in the range of 50 Nm to 200 Nm, and more preferably between 75 Nm and 150 Nm, is contemplated to transition the tab 322 from a first unbroken state to a second broken state. It should be understood that the separation device 320 can be located at any desired position along the axial extension length of the tubular sheath assembly 312 and the steering shaft assembly 318 as needed.

[0039] According to another aspect of this disclosure, a method for assembling a steering column assembly 10 to the body of a motor vehicle is provided. The method includes providing tubular sheath assemblies 12, 112, 212, 312, which define a hole 14 extending along a longitudinal axis 16 between a lower end 12a and an upper end 12b of the sheath. Furthermore, steering shaft assemblies 18, 118, 218, 318 are disposed along the central axis 16 through the hole 14, and in a first state, separation devices 20, 120, 220, 320 are connected to the tubular sheath assemblies 12, 112, 212, 312 and the steering shaft assemblies 18, 118, 218, 318 to prevent the steering shaft from rotating relative to the tubular sheath assembly. Then, the steering column assembly 10 is attached to the body of the motor vehicle, and torque is applied to the steering shaft assemblies 18, 118, 218, 318 to switch the separation devices 20, 120, 220, 320 to a second state in which the steering shaft assemblies 18, 118, 218, 318 can rotate freely relative to the tubular sheath assemblies 12, 112, 212, 312.

[0040] The method may further include providing a separation device 20, 120, 220, 320 having at least one fragile fragment 22, 122, 222, 322, the at least one fragile fragment having an unbroken state and a broken state, wherein the separation device 20, 120, 220, 320 is in a first state in the unbroken state and in a second state in the broken state, and wherein when torque is applied to the steering shaft assembly 18, 118, 218, 318, the at least one fragile fragment 22, 122, 222, 322 is able to transition from the unbroken state to the broken state.

[0041] The method may further include providing separation devices 20, 120, 220, 320 having outer components 28a, 128a, 228a, 328a and inner components 28b, 128b, 228b, 328b, and fixing the outer components 28a, 128a, 228a, 328a to prevent rotation with the tubular sheath assemblies 12, 112, 212, 312, and fixing the inner components 28b, 128b, 228b, 328b to prevent rotation with the steering shaft assemblies 18, 118, 218, 318, wherein at least one of the components 28a, 128a, 228a, 328a is a fragile component 22, 128a, 228a, 328a. When 22 and 322 are in an unbroken state, they connect the external components 28a, 128a, 228a, and 328a to the internal components 28b, 128b, 228b, and 328b to maintain the separation devices 20, 120, 220, and 320 in a first state, and when at least one of the fragile fragments 22, 122, 222, and 322 is in a broken state, it disengages the external components 28a, 128a, 228a, and 328a from the internal components 28b, 128b, 228b, and 328b to place the separation devices 20, 120, 220, and 320 in a second state.

[0042] Although the invention has been described in detail with reference to only a limited number of embodiments, it should be readily understood that the invention is not limited to these disclosed embodiments. Rather, the invention can be modified to include any number of variations, alterations, substitutions, or equivalent arrangements not previously described but commensurate with the spirit and scope of the invention. Furthermore, while various embodiments of the invention have been described, it should be understood that aspects of the invention may include only some of the embodiments described. Various elements or features of a particular embodiment are generally not limited to that particular embodiment, but are interchangeable where applicable and can be used in selected embodiments, even if not explicitly shown or described. Therefore, the invention should not be considered as limited by the foregoing description.

Claims

1. A steering column assembly, comprising: A tubular sheath assembly, defined by a hole extending along a central axis between the lower end and the upper end of the sheath; A steering shaft assembly extends along the central axis through the hole between the lower end and the upper end of the steering shaft; as well as A separation device extends between the tubular sheath assembly and the steering shaft assembly. The separation device has a first state and a second state. In the first state, it prevents the steering shaft assembly from rotating relative to the tubular sheath assembly. In the second state, the steering shaft assembly rotates freely relative to the tubular sheath assembly. The separation device has at least one fragile fragment having an unbroken state and a broken state. In the unbroken state, the separation device is in the first state. In the broken state, the separation device is in the second state.

2. The steering column assembly according to claim 1, wherein, The separation device has an outer member fixed to prevent rotation with the tubular sheath assembly and an inner member fixed to prevent rotation with the steering shaft assembly. The at least one fragile component, when in the unbroken state, engages the outer member with the inner member to maintain the separation device in the first state, and when in the broken state, the at least one fragile component disengages the outer member from the inner member to place the separation device in the second state.

3. The steering column assembly according to claim 2, wherein, The outer component is secured to the tubular sheath assembly via at least one fastener, and the inner component is secured by an anti-rotation feature to prevent rotation with the steering shaft assembly.

4. The steering column assembly according to claim 3, wherein, The anti-rotation feature includes a non-circular through-hole in the internal component and a non-circular outer surface on the steering shaft assembly, the non-circular outer surface extending through the non-circular through-hole.

5. The steering column assembly according to claim 4, wherein, The non-circular outer surface and the non-circular through opening fit together.

6. The steering column assembly according to claim 2, wherein, The outer component extends along a first plane, and the inner component extends along a second plane. When the separation device is in the second state, the first plane and the second plane extend along the central axis in a relationship that is axially spaced apart from each other and in a relationship that is substantially parallel to each other.

7. The steering column assembly according to claim 2, wherein, The at least one fragile piece comprises a plurality of fragile pieces spaced apart from each other around the central axis.

8. The steering column assembly according to claim 2, wherein, The outer component has an inner periphery, and the inner component has an outer periphery, wherein the at least one fragile component extends from the inner periphery to the outer periphery when in the unbroken state.

9. The steering column assembly according to claim 1, wherein, The steering shaft assembly has an outer surface with a groove extending into it, and the at least one fragile piece is disposed in the groove when in the unbroken state.

10. The steering column assembly according to claim 9, wherein, The at least one fragile fragment has a weak region to facilitate the transition of the at least one fragile fragment from the unbroken state to the broken state.

11. The steering column assembly according to claim 2, wherein, The steering shaft assembly has an outer shaft surface having a shaft opening extending therein, and the tubular sheath assembly has a wall having a sheath opening extending through it, the outer member being disposed within the sheath opening, and the inner member being disposed within the shaft opening, wherein the at least one fragile component, in the unbroken state, connects the outer member to the inner member.

12. The steering column assembly of claim 11, wherein, The internal component snaps into the shaft opening.

13. A steering shaft anti-rotation separation device for a steering column assembly, the steering column assembly having a tubular sheath assembly and a steering shaft assembly extending through the tubular sheath assembly, the steering shaft anti-rotation separation device comprising: An external component, an internal component, and at least one fragile component are provided. The external component is configured to be fixed to prevent rotation with the tubular sheath assembly, and the internal component is configured to be fixed to prevent rotation with the steering shaft assembly. The at least one fragile component, in an unbroken state, connects the external component to the internal component to maintain the anti-rotation separation device as a single integral material piece, wherein the external component and the internal component are fixed to prevent movement relative to each other. In a broken state, the at least one fragile component disengages the external component from the internal component, and in the broken state, the single integral material piece is converted into a separate material piece, wherein the external component and the internal component are movable relative to each other.

14. The steering shaft anti-rotation separation device according to claim 13, wherein, The outer component has an inner periphery, and the inner component has an outer periphery, wherein the at least one fragile fragment extends from the inner periphery to the outer periphery when in the unbroken state.

15. The steering shaft anti-rotation separation device according to claim 14, wherein, The outer component extends along a first plane, and the inner component extends along a second plane, the first plane and the second plane extending in a generally parallel and spaced-apart relationship.

16. The steering shaft anti-rotation separation device according to claim 14, wherein, The internal component has a non-circular through-hole configured to receive the non-circular outer surface of the steering shaft assembly passing through it.

17. The steering shaft anti-rotation separation device according to claim 16, wherein, The outer member has at least one flange with a fastener opening configured to receive a fastener passing through it to facilitate securing the outer member to the tubular sheath assembly.

18. A method of assembling a steering column assembly to the body of a motor vehicle, comprising: A tubular sheath assembly is provided, the tubular sheath assembly defining a hole extending along a central axis between a lower end and an upper end of the sheath; A steering shaft assembly is positioned to pass through the hole along the central axis; as well as In the first state, the separation device is connected to the tubular sheath assembly and the steering shaft assembly to prevent the steering shaft from rotating relative to the tubular sheath assembly; The steering column assembly is attached to the body of the motor vehicle; as well as A torque is applied to the steering shaft assembly to switch the separation device to a second state, in which the steering shaft assembly rotates freely relative to the tubular sheath assembly.

19. The method of claim 18, further comprising providing the separation device having at least one fragile fragment having an unbroken state and a broken state, wherein the separation device is in the first state in the unbroken state and in the second state in the broken state, and causing the at least one fragile fragment to transition from the unbroken state to the broken state when the torque is applied to the steering shaft assembly.

20. The method of claim 19, further comprising providing the separation device having an outer member and an inner member, and fixing the outer member to prevent rotation with the tubular sheath assembly, and fixing the inner member to prevent rotation with the steering shaft assembly, wherein, When the at least one fragile component is in the unbroken state, it connects the external component to the internal component to maintain the separation device in the first state, and wherein, when the at least one fragile component is in the broken state, it disconnects the external component from the internal component to place the separation device in the second state.

Images