Bracket for steering device and method for manufacturing the same, and steering device

Abstract

To provide a steering bracket that ensures good dimensional and shape accuracy and facilitates miniaturization of the steering device. [Solution] Each of the bracket members 35a and 35b has a mounting plate portion 36a and 36b supported by the vehicle body, a support plate portion 37a and 37b extending downward from the inner end in the width direction of the mounting plate portion 36a and 36b, and a welded surface 40a and 40b facing in a direction perpendicular to the plate thickness direction, and a bridge piece 38a and 38b extending inward in the width direction from the inner end in the width direction of the mounting plate portion 36a and 36b. A laser welded portion 41 is formed between the welded surfaces 40a and 40b of the pair of bracket members 35a and 35b, and is composed of weld metal that melts into each other or melts from one to the other.

Description

Technical Field

[0001] The present disclosure relates to a bracket for a steering device, a method for manufacturing the same, and a steering device.

Background Art

[0002] A steering device is incorporated in a vehicle such as an automobile, and transmits the movement of a steering wheel operated by a driver to a steering gear unit via a steering shaft, and imparts a steering angle to left and right steering wheels. The steering device includes a shock absorption device for mitigating an impact on a driver who collides with the steering wheel during a collision accident, and a position adjustment device that enables adjustment of the vertical position and / or the front-rear position of the steering wheel according to the physique and driving posture of the driver.

[0003] FIG. 13 shows a conventional structure of a steering device including a shock absorption device and a position adjustment device that enables adjustment of the vertical position of a steering wheel, described in Japanese Patent Application Laid-Open No. 2022-090202.

[0004] The steering device 100 includes a steering shaft 101 having a steering wheel 121 fixed to a rear end portion thereof, and a steering column 102 that rotatably supports the steering shaft 101 inside.

[0005] The steering shaft 101 is configured by combining a lower shaft (not shown) and an upper shaft 103 such that torque can be transmitted and relative displacement in the axial direction is possible. Thereby, during a collision accident, it is possible to shorten the overall length of the steering shaft 101 and mitigate an impact on a driver who collides with the steering wheel 121.

[0006] The steering column 102 is configured to be extendable and retractable in length by fitting the rear portion of the inner column 104, which is located at the front, and the front portion of the outer column 105, which is located at the rear, so that they can be displaced relative to each other in the axial direction. As a result, the steering column 102 is configured to be extendable and retractable in the axial direction together with the steering shaft 101.

[0007] The front portion of the inner column 104 is supported by a lower bracket 106, which is fixed to the vehicle body, allowing for oscillating displacement around the tilt axis 107. Furthermore, a column-side bracket 108, fixed to the front portion of the outer column 105, is supported by an upper bracket 109, which is supported by the vehicle body, allowing for vertical movement. This enables adjustment of the vertical position of the steering wheel 121.

[0008] The upper bracket 109 includes a pair of mounting plate portions 110 supported by the vehicle body, a pair of support plate portions 111 extending downward from the inner ends in the width direction of the pair of mounting plate portions 110 and positioned on both outer sides of the column-side bracket 108 in the width direction, and a bridge portion 112 connecting the inner ends in the width direction of the pair of mounting plate portions 110.

[0009] Each of the mounting plate sections 110 is supported by the detachment capsule 113, which is supported and fixed to the vehicle body, so as to be able to detach forward due to the forward impact load associated with a secondary collision.

[0010] Each of the support plate portions 111 has a bracket-side through hole 114 that extends in the vertical direction.

[0011] An adjustment rod 115 is inserted through the bracket-side through hole 114 and the column-side through hole provided in the column-side bracket 108. The steering device 100 operates an adjustment lever 116 fixed to the end of the adjustment rod 115, thereby expanding and contracting a cam device (not shown) to expand or contract the distance between the inner surfaces in the width direction of a pair of support plate portions 111. This makes it possible to adjust the clamping force on both outer surfaces in the width direction of the column-side bracket 108 by the inner surfaces in the width direction of the pair of support plate portions 111.

[0012] When the axial dimension of the cam device is reduced and the distance between the inner surfaces in the width direction of the pair of support plate portions 111 is increased during unclamping, the surface pressure between the inner surfaces in the width direction of the pair of support plate portions 111 and the outer surfaces in the width direction of the column-side bracket 108 decreases. In this state, the vertical position of the steering wheel 121 can be adjusted within the range in which the adjustment rod 115 can move inside the bracket-side through hole 114.

[0013] In contrast, when the axial dimension of the cam device is widened and the distance between the inner surfaces of the pair of support plate portions 111 in the width direction is reduced during clamping, the surface pressure between the inner surfaces of the pair of support plate portions 111 in the width direction and the outer surfaces of the column-side bracket 108 in the width direction increases, and the steering wheel 121 is held in the adjusted position.

[0014] In conventional structures, the upper bracket 109 is constructed by welding and fixing a pair of bracket members 117a and 117b by arc welding. Each bracket member 117a and 117b has a mounting plate portion 110, a support plate portion 111, and bridge pieces 118a and 118b extending inward in the width direction from the inner end of the mounting plate portion 110 in the width direction.

[0015] Of the pair of bracket members 117a and 117b, the bridge piece 118a of one bracket member 117a (the left side in Figure 13) has an inclined plate portion 119a that is inclined upward from the inner end in the width direction of the mounting plate portion 110 as it moves inward in the width direction, and a connecting piece 120a that protrudes inward in the width direction from the front side of the inner end of the inclined plate portion 119a.

[0016] Of the pair of bracket members 117a and 117b, the bridge piece 118b of the other bracket member 117b (the right side in Figure 13) has an inclined plate portion 119b that is inclined upward from the inner end in the width direction of the mounting plate portion 110 as it moves inward in the width direction, and a connecting piece 120b that protrudes inward in the width direction from the rear side of the inner end of the inclined plate portion 119b.

[0017] A pair of bracket members 117a and 117b are stretched between the rear side of the connecting piece 120a of one bracket member 117a and the front side of the connecting piece 120b of the other bracket member 117b, and are joined and fixed by a weld bead formed by arc welding, thereby constituting the upper bracket 109. The bridge portion 112 of the upper bracket 109 is composed of a pair of bridge pieces 118a and 118b joined by arc welding. [Prior art documents] [Patent Documents]

[0018] [Patent Document 1] Japanese Patent Publication No. 2022-090202 [Overview of the Initiative] [Problems that the invention aims to solve]

[0019] In conventional steering devices 100, a pair of bracket members 117a and 117b constituting the upper bracket 109 are welded and fixed together by arc welding. The weld bead formed by arc welding is formed on the lower surface of the bridge portion 112. Because the weld bead formed by arc welding is relatively tall (for example, about 1.0 mm to 5.0 mm), it is necessary to ensure a large gap between the lower surface of the bridge portion 112 and the upper surface of the steering column 102 (outer column 105), which tends to make the steering device 100 larger.

[0020] In addition, arc welding has a large penetration width, a large range affected by the heat of welding, and is likely to cause a large distortion in the peripheral part. Therefore, there is room for improvement in terms of ensuring the dimensional accuracy and shape accuracy of the bridge part 112.

[0021] An object of the present disclosure is to provide a bracket for a steering device that can ensure good dimensional accuracy and shape accuracy and is easy to miniaturize the steering device.

Means for Solving the Problems

[0022] The bracket for a steering device according to one aspect of the present disclosure includes a pair of bracket members each having a mounting plate portion, a support plate portion, and a plate-like bridge piece.

[0023] The mounting plate portion is supported by the vehicle body.

[0024] The support plate portion extends downward from an end portion inside the width direction of the mounting plate portion.

[0025] The bridge piece has a welding surface facing a direction orthogonal to the plate thickness direction, and extends inward in the width direction from an end portion inside the width direction of the mounting plate portion.

[0026] The pair of bracket members are welded and fixed to each other in a state where the respective welding surfaces are in contact with each other.

[0027] In particular, in the bracket for a steering device according to one aspect of the present disclosure, a laser welding portion formed of welding metal that melts into each other or melts from one side to the other is formed between the welding surfaces of the pair of bracket members.

[0028] In the bracket for a steering device according to one aspect of the present disclosure, the respective welding surfaces of the pair of bracket members can be configured by surfaces facing each other in the front-rear direction.

[0029] In a steering device bracket according to one aspect of the present disclosure, the widthwise end faces of the bridge pieces of the pair of bracket members can face each other with a gap in between.

[0030] In a steering device bracket according to one aspect of the present disclosure, the bead of the laser-welded portion may be composed of a wobbling bead.

[0031] A steering device according to one aspect of this disclosure is: The steering shaft and A steering column that rotatably supports the steering shaft, A bracket that supports the steering column relative to the vehicle body, It is equipped with.

[0032] In particular, in a steering device according to one aspect of the present disclosure, the bracket is a bracket for a steering device according to one aspect of the present disclosure.

[0033] A method for manufacturing a steering device bracket according to one aspect of this disclosure is a method for manufacturing a steering device bracket according to one aspect of this disclosure, The method includes a step of joining the pair of bracket members by bringing the respective welding surfaces of the pair of bracket members into contact with each other, irradiating the contact area between the welding surfaces with laser light, and forming the laser-welded area at the contact point.

[0034] In a method for manufacturing a steering device bracket according to one aspect of the present disclosure, the laser beam can be irradiated from below while the bracket is mounted on the vehicle body. [Effects of the Invention]

[0035] According to one aspect of the present disclosure, a bracket for a steering device can be used to ensure good dimensional accuracy and shape accuracy, and to facilitate miniaturization of the steering device. [Brief explanation of the drawing]

[0036] [Figure 1] Figure 1 is a perspective view showing a steering device according to one embodiment of the present disclosure. [Figure 2] Figure 2 is a side view showing the steering device. [Figure 3] Figure 3 is a cross-sectional view taken along line AA in Figure 2. [Figure 4] Figure 4 is a cross-sectional view along line BB in Figure 2. [Figure 5] Figure 5 is a cross-sectional view along the CC line in Figure 2. [Figure 6] Figure 6 is a plan view showing the upper bracket removed from the steering device. [Figure 7] Figure 7 is an end view of the upper bracket as seen from the front. [Figure 8] Figure 8(A) is a partially enlarged view showing the bridge section before the laser weld is formed, Figure 8(B) is a partially enlarged view showing the bridge section after the laser weld is formed, and Figure 8(C) is a cross-sectional view of Figure 8(B) along the DD line. [Figure 9] Figures 9(A) to 9(H) are schematic diagrams showing eight examples of bead shapes in laser-welded areas. [Figure 10] Figures 10(A) to 10(C) are schematic diagrams showing three other examples of the bead shape in a laser welded area. [Figure 11] Figure 11 is a schematic cross-sectional view showing an example of the manufacturing process of the upper bracket. [Figure 12] Figure 12 is a perspective view showing an example of a center jig used in the manufacturing process of the upper bracket. [Figure 13] Figure 13 is a perspective view showing an example of a conventional steering device. [Modes for carrying out the invention]

[0037] An example of an embodiment of the present disclosure will be described with reference to Figures 1 to 12.

[0038] This example shows an application of a steering device bracket according to one aspect of the present disclosure to an upper bracket for supporting the intermediate portion of the steering column to the vehicle body.

[0039] The following describes the overall structure of the steering device 1 and the structure of the lower column 21 supported by the upper bracket 4, followed by a description of the structure of the upper bracket 4 and the manufacturing method of the upper bracket 4.

[0040] In the following explanation, unless otherwise specified, the front-rear direction refers to the front-to-back direction of the vehicle, the up-and-down direction refers to the up-and-down direction of the vehicle, and the width direction (left-to-right direction) refers to the width direction of the vehicle. The front-to-rear direction of the vehicle generally coincides with the axial direction of the steering column 3.

[0041] [Overall structure of the steering system] The steering system 1 comprises a steering shaft 2, a steering column 3, and an upper bracket 4.

[0042] A steering wheel (not shown) is fixed to the rear end of the steering shaft 2. The steering column 3 has a roughly cylindrical shape and rotatably supports the steering shaft 2 via a plurality of rolling bearings 5a, 5b, and 5c inside it. The upper bracket 4 supports the intermediate portion of the steering column 3 in the front-rear direction to the vehicle body.

[0043] The steering device 1 in this example further includes a lower bracket 6.

[0044] The lower bracket 6 supports the front portion of the steering column 3 to the vehicle body. In this example, the lower bracket 6 supports the front portion of the steering column 3 to the vehicle body via a gear housing 8 which is integrally provided with the front portion of the steering column 3.

[0045] The steering device 1 of this disclosure may optionally include a column-assist type electric assist device 7. The electric assist device 7 provides auxiliary power from an electric motor 9 to the steering shaft 2 via a reduction mechanism 11. The steering device 1 of this example includes a column-assist type electric assist device 7.

[0046] In this example, the electric assist device 7 is located on the front side of the steering column 3. The electric assist device 7 comprises a gear housing 8 integrally provided on the front side of the steering column 3, an electric motor 9 supported by the gear housing 8, a torque sensor 10 for measuring the torque input to the steering shaft 2, and a control unit (not shown).

[0047] The control unit controls the power supply to the electric motor 9 based on the measurement signal from the torque sensor 10. The output torque of the electric motor 9 is applied to the steering shaft 2 via a reduction mechanism 11 housed in the gear housing 8. This reduces the force required to operate the steering wheel. In this example, the reduction mechanism 11 is composed of a worm gear reducer, which meshes a worm (not shown) rotated by the electric motor 9 with a worm wheel 27 fitted and fixed to the steering shaft 2.

[0048] The steering device 1 of this disclosure includes a tilt mechanism for adjusting the vertical position of the steering wheel according to the driver's physique and driving posture. For this purpose, the front part of the steering column 3 is supported so as to be able to swing about a tilt axis 12 arranged in the width direction of the vehicle. In this example, a gear housing 8 integrally provided with the front part of the steering column 3 is supported relative to the lower bracket 6 so as to be able to swing about the tilt axis 12.

[0049] Furthermore, the steering device 1 is equipped with an expansion / contraction device 13 to enable switching between a clamped state, in which the upper bracket 4 holds the axial middle portion of the steering column 3, and an unclamped state, in which the upper bracket 4 does not hold the axial middle portion of the steering column 3. The expansion / contraction device 13 expands or contracts the distance between the widthwise inner surfaces of a pair of support plate portions 37a and 37b that constitute the upper bracket 4. This makes it possible to adjust the clamping force on both widthwise outer surfaces of the column-side bracket 29 by the widthwise inner surfaces of the pair of support plate portions 37a and 37b. In this example, the expansion / contraction device 13 includes an adjustment rod 14, an adjustment lever 15, and a cam device 16.

[0050] The adjustment rod 14 is inserted in the width direction through a pair of support plate portions 37a and 37b that constitute the upper bracket 4 and the axial intermediate portion of the steering column 3 (the rear side of the lower column 21). A nut 17 is screwed onto the tip of the adjustment rod 14.

[0051] The adjustment lever 15 and the cam mechanism 16 are positioned around the portion of the adjustment rod 14 between the head of the adjustment rod 14 and one of the support plate portions 37a that constitute the upper bracket 4.

[0052] A thrust bearing 18 is positioned around the portion of the adjustment rod 14 between the nut 17 and the other support plate portion 37b that constitutes the upper bracket 4.

[0053] The magnitude of the force that the upper bracket 4 exerts to hold the axial middle portion of the steering column 3 can be adjusted by swinging the adjustment lever 15 up and down to expand and contract the cam device 16.

[0054] A steering device according to one aspect of this disclosure may optionally include a telescopic mechanism for adjusting the fore-aft position of the steering wheel. In this case, the steering column is configured to be extendable and retractable in length by combining a substantially cylindrical lower column located at the front (lower) and a substantially cylindrical upper column located at the rear (upper) and allowing relative axial displacement. The steering shaft is configured to be extendable and retractable in length by connecting an inner shaft and an outer shaft in a manner that allows torque transmission, such as by spline engagement. The steering device 1 in this example does not include a telescopic mechanism.

[0055] Furthermore, a steering device according to one aspect of this disclosure may optionally include an impact mitigation mechanism for reducing the impact load applied to the driver's body during a secondary collision.

[0056] Specifically, the steering column can be configured to be extendable and retractable in length by combining a lower column and an upper column, and the steering shaft can be configured by combining a lower shaft supported only rotatably inside the lower column and an upper shaft supported only rotatably inside the upper column, enabling torque transmission and relative axial displacement, and the upper column can be configured to be supported so as to be able to detach forward from the vehicle body due to the impact load associated with a secondary collision. Alternatively, the entire steering column can be configured to be supported so as to be able to detach forward from the vehicle body due to the impact load associated with a secondary collision. The steering device 1 in this example is equipped with an impact mitigation mechanism.

[0057] In this example, both the steering shaft 2 and the steering column 3 have a non-extendable structure, meaning their overall length does not extend or retract. Therefore, the entire steering column 3 is supported relative to the vehicle body in a way that allows it to detach forward due to the impact load associated with a secondary collision.

[0058] In this example, the upper bracket 4 and the lower bracket 6 are each locked to the detachment capsules 19a and 19b, which are supported and fixed to the vehicle body, so that they can detach forward due to the impact load associated with a secondary collision.

[0059] Specifically, the notches 56 opening at the rear edges of the mounting plate portions 36a and 36b that constitute the upper bracket 4 are locked to the detachment capsule 19a, which is supported and fixed to the vehicle body, so that it can detach forward due to the impact load associated with a secondary collision. In addition, the notches provided at two positions in the width direction of the upper plate portion 20 that constitute the lower bracket 6, and which open at the rear edge of the upper plate portion 20, are locked to the detachment capsule 19b, which is supported and fixed to the vehicle body, so that it can detach forward due to the impact load associated with a secondary collision.

[0060] In this example, the steering column 3 is constructed by connecting and fixing a lower column 21 and an upper column 22 in a way that prevents relative axial displacement. A gear housing 8 is integrally provided on the front part of the lower column 21. The front opening of the gear housing 8 is closed by a roughly hollow circular plate-shaped cover 23.

[0061] Furthermore, the steering shaft 2 is constructed by connecting a solid lower shaft 24 located at the front and a substantially cylindrical upper shaft 25 located at the rear via a torsion bar 26. A worm wheel 27, which constitutes the reduction mechanism 11, is externally fitted and fixed to the axial middle portion of the lower shaft 24.

[0062] In this example, the portion of the lower shaft 24 in front of the portion to which the worm wheel 27 is fitted is rotatably supported inside the cover 23 by a rolling bearing 5a, and the portion of the lower shaft 24 in rear of the portion to which the worm wheel 27 is fitted is rotatably supported inside the gear housing 8 by a rolling bearing 5b. In addition, the axial middle portion of the upper shaft 25 is rotatably supported inside the upper column 22 by a rolling bearing 5c.

[0063] [Roa Column] The lower column 21 includes a column body 28, a column-side bracket 29, and a column-side through hole (not shown).

[0064] The column body 28 has a roughly cylindrical shape and is positioned around the steering shaft 2.

[0065] The front portion of the column body 28 is supported to allow oscillation around a tilt axis 12, which is positioned in the width direction of the vehicle. In this example, a gear housing 8, integrally provided with the front portion of the column body 28, is supported relative to the lower bracket 6 to allow oscillation displacement around the tilt axis 12. The gear housing can also be configured separately from the column body and connected and fixed to the column body by welding, screwing, or the like. Furthermore, when applying the steering device of this disclosure to a steering device that does not have a column-assist type electric assist device, the front portion of the column body can also be directly supported relative to the lower bracket to allow oscillation around the tilt axis.

[0066] The rear portion of the column body 28 is coupled to the front portion of the upper column 22 in a way that prevents relative axial displacement. In this example, the column body 28 and the upper column 22 are joined and fixed together by screwing a bolt 31, which is inserted through a through hole in the upper flange 30 provided at the front end of the upper column 22, into a threaded hole in the lower flange 32 provided at the rear end of the column body 28.

[0067] Furthermore, the column body and the upper column can also be joined and fixed by inserting a bolt through a through hole in the upper flange provided at the front end of the upper column and a through hole in the lower flange provided at the rear end of the column body, and screwing a nut onto the tip of the bolt. Alternatively, the rear part of the column body and the front part of the upper column can be joined and fixed by welding. In cases such as this example, where the steering device of this disclosure is applied to a structure that does not have a telescopic mechanism and has an impact mitigation mechanism that causes the entire steering column to detach forward from the vehicle body in the event of a secondary collision, the entire steering column can be constructed as a single unit, i.e., the upper column can be omitted.

[0068] The column-side bracket 29 is fixed to the column body 28 and constitutes a portion that is sandwiched by a pair of support plate portions 37a and 37b of the upper bracket 4.

[0069] In this example, the column-side bracket 29 is integrally provided with the column body 28 such that it protrudes (bulges) in the width direction and downward from the lower half of the outer peripheral surface of the rear side of the column body 28. However, the column-side bracket can also be constructed separately from the column body and joined and fixed to the column body by welding or the like.

[0070] The column-side bracket 29 has overhangs 33 projecting outward in the width direction on the upper and lower portions on both outer sides in the width direction. Each of the overhangs 33 extends in the front-rear direction. The tip surface (outer surface in the width direction) of each overhang 33 is provided with a flat clamping surface 34 that receives clamping force from the inner surfaces in the width direction of the support plate portions 37a and 37b that constitute the upper bracket when clamped.

[0071] The adjustment rod 14 of the expansion / contraction device 13 is inserted in the width direction through the column-side through hole. In this example, the column-side through hole is made up of a circular hole that penetrates the column-side bracket 29 in the width direction.

[0072] [Upper Bracket] The upper bracket 4 supports the vehicle body at the intermediate portion of the steering column 3 in the front-rear direction. Specifically, the upper bracket 4 supports the vehicle body at the column-side bracket 29 of the lower column 21.

[0073] The upper bracket 4 comprises a pair of bracket members 35a and 35b. Each of the pair of bracket members 35a and 35b has a mounting plate portion 36a and 36b, a support plate portion 37a and 37b, and a plate-shaped bridge piece 38a and 38b.

[0074] Each of the bracket members 35a and 35b is made of a metal plate with sufficient rigidity, such as steel or an aluminum alloy. In this example, each of the bracket members 35a and 35b is integrally manufactured by bending a metal plate. However, each of the bracket members can also be constructed by joining and fixing multiple parts together by welding or other means. In this case, all parts can be made from the same type of metal, or some parts can be made from different types of metal.

[0075] Mounting plate section The mounting plates 36a and 36b are supported by the vehicle body. In this example, the mounting plates 36a and 36b are normally supported by the vehicle body, but in the event of a collision, they detach forward based on the impact of a secondary collision, allowing the steering column 3 to be displaced forward. For this purpose, the mounting plates 36a and 36b have notches 56 that open on their rear edges, and these notches 56 are locked to a detachment capsule 19a, which is fixed to the vehicle body by bolts (not shown), allowing them to detach forward due to the impact load associated with a secondary collision.

[0076] In this example, the mounting plates 36a and 36b are configured to be substantially flat and are spaced apart from each other in the width direction. Furthermore, the mounting plates 36a and 36b are positioned at the same height and substantially parallel to each other in the vertical direction.

[0077] 《Support plate part》 The support plate portions 37a and 37b extend downward from the inner ends in the width direction of the mounting plate portions 36a and 36b. In this example, each of the support plate portions 37a and 37b is bent downward at approximately a right angle from the rear portion of the inner end in the width direction of the mounting plate portions 36a and 36b.

[0078] The support plates 37a and 37b are positioned on both outer sides of the steering column 3 in the width direction. In this example, the support plates 37a and 37b are positioned on both outer sides of the column-side bracket 29 in the width direction. The support plates 37a and 37b are positioned opposite each other, spaced apart in the width direction.

[0079] Each of the support plate portions 37a and 37b has a bracket-side through hole 39 through which the adjustment rod 14 is inserted in the width direction. In this example, the bracket-side through hole 39 is made up of an elongated hole that extends in the vertical direction. More specifically, the bracket-side through hole 39 has a substantially partial annular shape centered on the tilt axis 12 when viewed from the width direction.

[0080] Bridge piece The bridge pieces 38a and 38b have welded surfaces 40a and 40b facing in a direction perpendicular to the plate thickness direction, and extend inward in the width direction from the inner ends in the width direction of the mounting plate portions 36a and 36b.

[0081] A pair of bracket members 35a and 35b are welded together with their respective welding surfaces 40a and 40b in contact. This constitutes the upper bracket 4. In addition, bridge pieces 38a and 38b form a bridge section 42 that connects the mounting plate sections 36a and 36b and the support plate sections 37a and 37b, which are located on both sides of the steering column 3 in the width direction.

[0082] Each of the welding surfaces 40a and 40b may be composed of surfaces that face each other in the front-to-back direction, or surfaces that face each other in the width direction. Alternatively, the welding surfaces 40a and 40b may be composed of surfaces that are inclined in the front-to-back direction with respect to the width direction.

[0083] Furthermore, in order to hold the steering wheel in the adjusted position, it is preferable that the distance between the inner surfaces in the width direction of the support plate portions 37a and 37b is reduced, and that the laser welded portion 41 extends in the width direction from the perspective of ensuring strength against the force that clamps the column-side bracket 29 from both sides in the width direction by the support plate portions 37a and 37b. That is, it is preferable that the welded surfaces 40a and 40b are each composed of surfaces that face each other in the front-rear direction.

[0084] When the welded surfaces 40a and 40b are each composed of surfaces that face each other in the front-rear direction, the widthwise end faces of the bridge pieces 38a and 38b of the pair of bracket members 35a and 35b can face each other with a gap in between. However, the widthwise end faces of the bridge pieces of the pair of bracket members can also be in contact with each other.

[0085] In this example, the welded surfaces 40a and 40b are each composed of surfaces that face each other in the front-to-back direction. Furthermore, the widthwise end faces of the bridge pieces 38a and 38b of the pair of bracket members 35a and 35b face each other with a gap in between. Specifically, each bridge piece 38a and 38b has opposing surfaces 43a to 43d that face each other with a gap in the widthwise direction.

[0086] In this example, each of the bridge pieces 38a and 38b has inclined plate portions 44a and 44b that extend upward from the inner ends in the width direction of the mounting plate portions 36a and 36b toward the inside in the width direction, and upper plate portions 45a and 45b that extend toward the inside in the width direction from the inner ends in the width direction of the inclined plate portions 44a and 44b. The upper plate portions 45a and 45b are arranged substantially parallel to the mounting plate portions 36a and 36b. That is, the thickness direction of the upper plate portions 45a and 45b is oriented in the vertical direction.

[0087] Of the pair of bracket members 35a and 35b, the upper plate portion 45a of the bridge piece 38a constituting the first bracket member 35a (the left side in Figures 6 and 7) has a substantially rectangular plate-shaped base portion 46a positioned outward in the width direction, and a substantially rectangular plate-shaped connecting piece 47a that protrudes inward in the width direction from the front side of the end of the base portion 46a inward in the width direction.

[0088] The bridge piece 38a has a first welding surface 40a on the rear side surface of the connecting piece 47a. The bridge piece 38a also has a first front opposing surface 43a on the tip surface of the connecting piece 47a, and a first rear opposing surface 43b on the widthwise inner surface of the rear side of the base 46a. The first welding surface 40a can be provided on the rear side surface of the connecting piece 47a along its entire width, or it can be provided in a portion of the width.

[0089] Of the pair of bracket members 35a and 35b, the upper plate portion 45b of the bridge piece 38b that constitutes the second bracket member 35b (the other one on the right in Figures 6 and 7) has a substantially rectangular plate-shaped base portion 46b positioned outward in the width direction, and a substantially rectangular plate-shaped connecting piece 47b that protrudes inward in the width direction from the rear side of the end of the base portion 46b inward in the width direction.

[0090] The bridge piece 38b has a second welding surface 40b on the front surface of the connecting piece 47b. The bridge piece 38b also has a second rear opposing surface 43c on the tip surface of the connecting piece 47b, and a second front opposing surface 43d on the widthwise inner surface of the front part of the base 46b. The second welding surface 40b may be provided on the front surface of the connecting piece 47b along its entire width, or it may be provided in a part of the width.

[0091] In this example, a pair of bracket members 35a and 35b are welded together with the first welding surface 40a and the second welding surface 40b in contact in the front-rear direction, the first front opposing surface 43a and the second front opposing surface 43d facing each other with a gap in the width direction, and the first rear opposing surface 43b and the second rear opposing surface 43c facing each other with a gap in the width direction.

[0092] In one aspect of the present disclosure, a laser-welded portion 41 is formed between the welded surfaces 40a, 40b of a pair of bracket members 35a, 35b, and is composed of weld metal that melts into each other or melts from one to the other (from the first welded surface 40a to the second welded surface 40b, or from the second welded surface 40b to the first welded surface 40a). The laser-welded portion 41 can be formed over the entire contact area between the first welded surface 40a and the second welded surface 40b, or it can be formed on a part of the contact area.

[0093] Furthermore, the term "melting together" includes cases where the weld metal contains both portions that melt from the first welding surface 40a toward the second welding surface 40b and portions that melt from the second welding surface 40b toward the first welding surface 40a.

[0094] In this example, a laser-welded area 41 is formed between the welded surfaces 40a and 40b of a pair of bracket members 35a and 35b, consisting of weld metal that melts into each other.

[0095] The laser-welded joint 41 is a butt weld formed by joining welding surfaces 40a and 40b that are perpendicular to the plate thickness direction together.

[0096] A bead (welding mark) is formed on the lower and / or upper surface of the bridge portion 42, which is constructed by joining bridge pieces 38a and 38b together by the laser welding portion 41.

[0097] The height of the bead of the laser-welded joint 41 is not limited to this value, but can be, for example, 0.1 mm or less, preferably 0.05 mm or less, and the width dimension of the bead is not limited to this value, but can be, for example, 2 mm or less, preferably 1 mm or less.

[0098] The planar shape of the laser-welded bead 41, as viewed from above and below, is not particularly limited, as long as it can weld and fix a pair of bracket members 35a and 35b together.

[0099] For example, the bead of the laser-welded joint 41 can be formed by a wobbling bead, as shown in Figure 9(A), which is created by moving the laser beam along the contact area between the welding surfaces 40a and 40b in a roughly circular motion during welding, or as shown in Figure 9(B), which is created by moving the laser beam along the contact area between the welding surfaces 40a and 40b in a roughly elliptical shape.

[0100] The bead of the laser-welded joint 41 can also be composed of a weaving bead that is approximately sinusoidal (see Figure 9(C)), approximately triangular (see Figure 9(D)), or approximately rectangular (see Figure 9(E)).

[0101] The bead of the laser-welded joint 41 can also be composed of multiple short straight lines that cross the contact area between the welding surfaces 40a and 40b and extend in the front-rear direction, as shown in Figure 9(F), or multiple short straight lines that cross the contact area between the welding surfaces 40a and 40b and extend in a direction inclined with respect to the front-rear direction, as shown in Figure 9(G).

[0102] Alternatively, the bead of the laser-welded joint 41 can be formed by a linear stringer bead along the contact area between the welding surfaces 40a and 40b, as shown in Figure 9(H).

[0103] Alternatively, the bead of the laser-welded joint 41 can be constructed by combining two or more shapes shown in Figures 9(A) to 9(H). For example, as shown in Figure 10(A), the linear shape shown in Figure 9(F) can be combined with the shape shown in Figure 9(H). Also, as shown in Figure 10(B), the shape shown in Figure 9(F) can be combined with the shape shown in Figure 9(G). Furthermore, as shown in Figure 10(C), two roughly triangular wave-shaped shapes shown in Figure 9(D) can be combined with a half-period phase shift. It is also possible to vary the type of weld bead depending on the widthwise position of the contact area.

[0104] In this example, the bead of the laser-welded joint 41 is composed of a wobbling bead, as shown in Figure 9(A), which is formed by moving the laser beam along the contact area between the welding surfaces 40a and 40b in a roughly circular motion during welding.

[0105] Plate Guide The upper bracket 4 in this example further comprises a pair of plate guides 49 that constitute an impact absorption mechanism 48. However, when implementing a steering device bracket according to one aspect of this disclosure, it is optional for the upper bracket to include plate guides.

[0106] The impact absorption mechanism 48 is a component that absorbs impact energy during a secondary collision, and comprises a pair of plate guides 49 and a pair of impact absorbing plates 50.

[0107] Each of the plate guides 49 is a pressed metal plate and comprises a side plate portion 51, a bottom plate portion 52, and a rear plate portion 53.

[0108] The side plate portion 51 extends downward from the lower surface of the mounting plate portions 36a and 36b. Specifically, the side plate portion 51 is welded and fixed to the mounting plate portions 36a and 36b with its upper end in contact with the lower surface of the mounting plate portions 36a and 36b.

[0109] The bottom plate portion 52 extends inward in the width direction from the lower end of the side plate portion 51 and is positioned below the mounting plate portions 36a and 36b, approximately parallel to the mounting plate portions 36a and 36b.

[0110] The rear plate portion 53 extends upward from the rear end of the bottom plate portion 52. The rear plate portion 53 has a protrusion 54 that projects inward in the width direction at its inner end in the width direction. The protrusion 54 is locked into locking holes 55 provided in the support plate portions 37a and 37b.

[0111] The impact-absorbing plate 50 is a strip-shaped metal plate that is bent into a horizontal J-shape when viewed in the width direction. The rear end of the impact-absorbing plate 50 is fixed to the vehicle body together with the release capsule 19a, and the front part is housed in the plate guide 49. The impact-absorbing plate 50 absorbs the impact of a secondary collision by being pressed forward by the rear plate portion 53 of the plate guide 49 and undergoing plastic deformation.

[0112] In the steering device 1 of this example, when holding the steering wheel in a desired vertical position, the steering wheel is moved to the desired vertical position, and then the adjustment lever 15 is rotated in a predetermined direction (for example, upward) around the adjustment rod 14. This expands the widthwise dimension of the cam device 16, and reduces the distance between the inner surfaces in the widthwise direction of the support plate portions 37a and 37b of the pair of bracket members 35a and 35b. At this time, the inner surfaces in the widthwise direction of the support plate portions 37a and 37b press against the respective clamping surfaces 34. As a result, the respective support plate portions 37a and 37b clamp both outer surfaces in the widthwise direction of the column-side bracket 29 from both sides in the widthwise direction. As a result, the steering wheel is held in the adjusted vertical position.

[0113] When adjusting the vertical position of the steering wheel, the adjustment lever 15 is swung in the opposite direction to the predetermined direction (for example, downward). This reduces the widthwise dimension of the cam device 16, and widens the gap between the inner surfaces in the widthwise direction of the support plate portions 37a and 37b of the pair of bracket members 35a and 35b. As a result, the pressing force between the support plate portions 37a and 37b decreases, reducing the force with which the support plate portions 37a and 37b hold both outer surfaces in the widthwise direction of the column-side bracket 29. In this state, the vertical position of the steering wheel can be adjusted within the range in which the adjustment rod 14 can move inside the bracket-side through-hole 39.

[0114] [Manufacturing method for upper brackets] The manufacturing method of the upper bracket 4 of the present disclosure includes a step of joining a pair of bracket members 35a and 35b by irradiating the contact portion between the respective welding surfaces 40a and 40b of a pair of bracket members 35a and 35b with laser light while the respective welding surfaces 40a and 40b of the bracket members 35a and 35b are in contact with each other, thereby forming a laser weld portion 41 at the contact portion.

[0115] In the manufacturing method of the upper bracket 4 in this example, the process of manufacturing each bracket member 35a and 35b is carried out before the process of joining the pair of bracket members 35a and 35b by laser welding.

[0116] The method for manufacturing each bracket member 35a and 35b is not particularly limited. In this example, each bracket member 35a and 35b is integrally manufactured by bending a metal plate. Specifically, a flat intermediate member is obtained by punching a metal plate, and then the bracket members 35a and 35b are obtained by bending the intermediate member.

[0117] However, when implementing a method for manufacturing a steering device bracket according to one aspect of this disclosure, each of a pair of bracket members can also be manufactured by joining and fixing multiple parts together by welding or other means.

[0118] Next, the process of joining a pair of bracket members 35a and 35b by laser welding will be explained with reference to Figures 11 and 12.

[0119] A pair of bracket members 35a and 35b are joined together by irradiating the contact area between their respective welding surfaces 40a and 40b with laser light from either the lower side (the side from which the support plates 37a and 37b extend from the inner ends in the width direction of the mounting plates 36a and 36b) or the upper side (the side opposite to the side from which the support plates 37a and 37b extend from the inner ends in the width direction of the mounting plates 36a and 36b) when the bracket members are mounted on the vehicle body, thereby forming a laser welded portion 41 at the contact area. In this example, in the process of joining the pair of bracket members 35a and 35b, laser light is irradiated from the lower side (the side from which the support plates 37a and 37b extend) when the bracket members are mounted on the vehicle body.

[0120] In this example, a process of joining a pair of bracket members 35a and 35b is performed using one center jig 57, two side jigs 58, one base jig 59, and a laser head 60 connected to a laser processing machine body (not shown).

[0121] The outer surface of the center jig 57 in the width direction is composed of a flat surface that can make surface contact with the inner surfaces of the support plate portions 37a and 37b in the width direction. The width dimension of the center jig 57 is the same as the distance between the inner surfaces of the support plate portions 37a and 37b in the width direction that constitute the upper bracket 4 in the completed state. In this example, the vertical dimension of the center jig 57 is larger than the vertical dimension of the support plate portions 37a and 37b, but it may be the same as the vertical dimension of the support plate portions 37a and 37b, or smaller than the vertical dimension of the support plate portions 37a and 37b.

[0122] In this example, the center jig 57 has a structure through which laser light can pass. Specifically, as shown in Figure 12, the center jig 57 has a hollow skeletal structure rather than a solid structure. When implementing a method for manufacturing a steering device bracket according to one aspect of this disclosure, the center jig is not limited to the structure shown in Figure 12, and other structures can be adopted, such as a structure that has through holes for allowing laser light to pass through.

[0123] The center jig 57 has a pair of vertical plates 61, a top plate 62, and a pair of beams 63.

[0124] A pair of vertical plates 61 are spaced apart in the width direction and arranged approximately parallel to each other. The outer surfaces of the vertical plates 61 constitute the outer surfaces in the width direction of the center jig 57. The upper ends of the pair of vertical plates 61 are connected to the outer ends of the top plate 62 in the width direction. The top plate 62 is constructed in a roughly rectangular shape. A pair of beams 63 are spaced apart in the front-to-back direction (front-to-back direction in Figure 12) and arranged approximately parallel to each other. In Figure 12, the front side of Figure 12 corresponds to the rear side, and the back side of Figure 12 corresponds to the front side. The ends of each beam 63 in the longitudinal direction are connected to the lower ends of the pair of vertical plates 61. The center jig can be constructed by omitting the pair of beams and consisting of a pair of vertical plates and a top plate, or by omitting the top plate and consisting of a pair of vertical plates and a pair of beams, provided that rigidity during clamping can be ensured.

[0125] The center jig 57 has a lower opening 64 in the area enclosed on all four sides by a pair of vertical plates 61 and a pair of beams 63. The lower opening 64 extends over almost the entire underside of the center jig 57. The center jig 57 also has a front opening 65 in the area enclosed on all four sides by a pair of vertical plates 61, a top plate 62, and one of the beams 63 positioned at the front. Furthermore, the center jig 57 has a rear opening 66 in the area enclosed on all four sides by a pair of vertical plates 61, a top plate 62, and the other beam 63 positioned at the rear.

[0126] The two side fixtures 58 are positioned on either side of the center fixture 57 in the width direction and are capable of relative movement in the width direction with respect to the center fixture 57.

[0127] The base jig 59 has a pair of mounting surfaces 67 on its upper end surface and a receiving recess 68 positioned between the pair of mounting surfaces 67 in the width direction. The receiving recess 68 has a depth dimension and a width dimension that can accommodate the bridge portion 42 that constitutes the upper bracket 4.

[0128] In order to join a pair of bracket members 35a and 35b by laser welding, first, the pair of bracket members 35a and 35b are joined so that the first welding surface 40a and the second welding surface 40b are in contact, and a gap in the width direction is interposed between the first front opposing surface 43a and the second front opposing surface 43d, and between the first rear opposing surface 43b and the second rear opposing surface 43c. Combine them while facing each other.

[0129] With the pair of bracket members 35a and 35b assembled, the support plate portions 37a and 37b of the pair of bracket members 35a and 35b are simultaneously clamped using the center jig 57 and the two side jigs 58. Specifically, the pair of bracket members 35a and 35b are positioned upside down compared to their mounting state to the vehicle body, and the bridge pieces 38a and 38b protrude downward from the center jig 57 and the side jigs 58, and the respective support plate portions 37a and 37b are clamped. This forms a clamp assembly 69 consisting of the center jig 57, the two side jigs 58, and the pair of bracket members 35a and 35b.

[0130] Before and after clamping the support plate portions 37a and 37b of the pair of bracket members 35a and 35b with the center jig 57 and the two side jigs 58, the respective mounting plate portions 36a and 36b are set on the base jig 59. Specifically, the respective mounting plate portions 36a and 36b are placed on a pair of mounting surfaces 67, and the respective bridge pieces 38a and 38b are housed inside the receiving recesses 68.

[0131] As described above, after setting the pair of bracket members 35a and 35b, laser light is irradiated from the laser head 60. Specifically, with the welding surfaces 40a and 40b of the pair of bracket members 35a and 35b in contact with each other, the tip of the laser head 60 is positioned opposite the contact point between the welding surfaces 40a and 40b, and laser light is irradiated from the laser head 60 to the contact point.

[0132] The laser head 60 is positioned either in front of or behind the center jig 57. When the laser head 60 is positioned in front of the center jig 57, the light from the laser head 60 is passed through the front opening 65 and the lower opening 64 in that order, irradiating the contact area between the welding surfaces 40a and 40b. Conversely, when the laser head 60 is positioned behind the center jig 57, the light from the laser head 60 is passed through the rear opening 66 and the lower opening 64 in that order, irradiating the contact area between the welding surfaces 40a and 40b. This irradiates the contact area between the welding surfaces 40a and 40b from below, in the state in which it is mounted on the vehicle body.

[0133] In this example, the laser head 60 is moved in the width direction while being wobbled in the back-and-forth direction to irradiate the contact area between the welding surfaces 40a and 40b with laser light. Specifically, the laser head 60 is moved in the width direction while being wobbled in the back-and-forth direction so that the welding pattern of the laser-welded area 41 formed between the welding surfaces 40a and 40b takes on a desired shape. In this example, the laser head 60 is moved in the width direction while being wobbled in a circular motion so that the bead of the laser-welded area 41 takes on the shape shown in Figure 9(A).

[0134] This forms a laser-welded area 41 between the welding surfaces 40a and 40b, which is composed of weld metal that melts into each other. After the laser-welded area 41 is formed, the clamps by the two side jigs 58 are released, and the center jig 57 is pulled out from between the support plate sections 37a and 37b.

[0135] According to this disclosure, good dimensional accuracy and shape accuracy can be ensured, and the steering device 1 can be easily miniaturized.

[0136] In other words, the upper bracket 4 in this example is constructed by welding and fixing a pair of bracket members 35a and 35b by a laser weld 41. The height of the bead of the laser weld 41 is sufficiently lower than the height of the bead of a weld formed by arc welding, which has a similar level of joint strength. Therefore, with the upper bracket 4 in this example, the gap between the lower surface of the bridge portion 42 and the outer surface of the lower column 21 can be kept smaller compared to the case where a pair of bracket members are welded and fixed by arc welding, making it easier to miniaturize the steering device 1.

[0137] Furthermore, compared to arc welding, laser welding allows for greater penetration depth, thus shortening processing time and minimizing the penetration width, thereby reducing the thermal effects of welding. In this example, the upper bracket 4 is constructed by welding and fixing a pair of bracket members 35a and 35b by the laser welding section 41, thus ensuring good dimensional and shape accuracy of the upper bracket 4.

[0138] Furthermore, in this example, a pair of bracket members 35a and 35b are welded together with a gap in the width direction between the first front opposing surface 43a and the second front opposing surface 43d, and between the first rear opposing surface 43b and the second rear opposing surface 43c. Therefore, without requiring excessively high dimensional accuracy in the width direction of the pair of bracket members 35a and 35b, the spacing between the inner surfaces in the width direction of the pair of support plate portions 37a and 37b can be precisely controlled, making it possible to set the force that holds the steering wheel in the adjusted position to an appropriate size. Consequently, the manufacturing cost of the upper bracket 4 and, furthermore, the steering device 1 can be reduced. [Explanation of Symbols]

[0139] 1. Steering system 2 Steering shaft 3. Steering column 4 Upper Bracket 5a, 5b, 5c Rolling efficient 6 Lower Bracket 7. Electric assist device 8 Gear Housing 9 Electric motor 10 Torque Sensor 11 Reduction mechanism 12 Tilt axes 13. Expanding / contracting device 14 Adjustment Rod 15 Adjustment lever 16 Cam mechanism 17 Nuts 18 Thrust bearings 19a, 19b Release capsule 20 Upper plate section 21 Roa Column 22 Upper Column 23 Lid 24 Lower Shaft 25 Upper Shaft 26 Torsion bar 27 Worm Wheel 28 Column body 29 Column-side bracket 30 Upper flange 31 volts 32 Lower flange 33 Overhang 34. Clamping surface 35a First bracket member 35b Second bracket member 36a, 36b Mounting plate section 37a, 37b Support plate part 38a, 38b Bridge piece 39 Bracket side through hole 40a First welding surface 40b Second welding surface 41 Laser Welded Section 42 Bridge section 43a First front opposing surface 43b First rear opposing surface 43c Second rear opposing surface 43d Second front opposing surface 44a, 44b Slanted plate part 45a, 45b Upper plate section 46a, 46b base 47a, 47b connecting piece 48 Shock absorption mechanism 49 Plate Guide 50 Shock-absorbing plates 51 Side plate part 52 Bottom plate part 53 Rear plate part 54 Convex part 55 Locking hole 56 Notches 57 Centering jig 58 Side jigs 59 Base jig 60 laser heads 61 vertical boards 62 Top plate 63 Beam 64 Lower opening 65 Front opening 66 Rear opening 67 Mounting surface 68 Receiving recess 69 Clamp Assembly 100 Steering System 101 Steering shaft 102 Steering column 103 Upper Shaft 104 Inner Column 105 Outer Column 106 Lower Bracket 107 Tilt axis 108 Column-side bracket 109 Upper Bracket 110 Mounting plate section 111 Support plate part 112 Bridge section 113 Withdrawal Capsule 114 Bracket side through hole 115 Adjustable Rod 116 Adjustment lever 117a, 117b Bracket members 118a, 118b Bridge piece 119a, 119b Slanted plate part 120a, 120b connecting piece 121 Steering Wheel

Claims

1. Each bracket member comprises a pair having a mounting plate portion supported by the vehicle body, a support plate portion extending downward from the inner end in the width direction of the mounting plate portion, and a plate-shaped bridge piece having a welded surface facing a direction perpendicular to the plate thickness direction, and extending inward in the width direction from the inner end in the width direction of the mounting plate portion. The pair of bracket members are welded together and fixed to each other with their respective welded surfaces in contact with each other. A laser-welded area is formed between the welded surfaces of the pair of bracket members, consisting of weld metal that melts into each other or melts from one to the other. Bracket for steering system.

2. The welded surfaces of each of the pair of bracket members are composed of surfaces that face each other in the front-rear direction. Bracket for steering device according to claim 1.

3. The widthwise end faces of the bridge pieces of the pair of bracket members face each other with a gap between them. Bracket for steering device according to claim 2.

4. The bead of the laser-welded section is composed of a wobbling bead. Bracket for steering device according to claim 1.

5. The steering shaft and A steering column that rotatably supports the steering shaft, The steering column is provided with a bracket that supports it relative to the vehicle body, A steering device wherein the bracket is a steering device bracket as described in any one of claims 1 to 4.

6. A method for manufacturing a steering device bracket according to any one of claims 1 to 4, The process includes joining the pair of bracket members by bringing the respective welding surfaces of the pair of bracket members into contact with each other, irradiating the contact area between the welding surfaces with laser light, and forming the laser-welded area at the contact point. A method for manufacturing a bracket for a steering system.

7. A method for manufacturing a steering device bracket according to claim 6, wherein the laser beam is irradiated from below while the bracket is mounted on the vehicle body.

Images