Steering system

Abstract

To provide a steering device that can effectively reduce steering vibration. [Solution] The steering device comprises a steering shaft to which a steering wheel is fixed at the end of the shaft, a steering column that rotatably supports the steering shaft, and a support bracket fixed to the vehicle frame and supporting the steering wheel side of the steering column. The support bracket is equipped with a pair of opposing clamping plates that clamp both sides of the steering column. The clamping plates have a multilayer structure consisting of a plurality of steel plates stacked in the direction of clamping the steering column and a damping material interposed between each steel plate. The clamping plates are formed with beads that protrude outward and extend in the vertical direction.

Description

Technical Field

[0001] The present invention relates to a steering device.

Background Art

[0002] One of the vibrations and noises that a vehicle such as an automobile receives during driving is steering vibration. This steering vibration is a phenomenon in which, during driving, an input from an uneven road surface is transmitted through the tires, suspension, and body, exciting the vibration of the steering wheel. When the steering shaft resonates, a driver holding the steering wheel perceives this as the vibration of the steering wheel.

[0003] As a technique for reducing the vibration and noise caused by steering vibration, it is conceivable to set the resonance frequency of components constituting a steering device such as a steering wheel, a steering column, and a steering support beam to a band that deviates from the resonance frequency of the vibration transmission path (tires, suspension, vehicle body, etc.).

[0004] To set the resonance frequency of components constituting a steering device to a band that deviates from the resonance frequency of components that form the vibration transmission path, it is necessary to reconstruct the material, shape, layout, etc., which is not practical.

[0005] Also, for example, Patent Document 1 (Japanese Unexamined Patent Application Publication No. 2024-147,119) discloses a technique in which a support portion for supporting an airbag module inside a steering wheel is used as a dynamic damper to attenuate the vibration transmitted to the steering wheel.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0007] However, the technology disclosed in Patent Document 1 uses a dynamic damper as the support part for the airbag module, which has the disadvantage of increasing the mass of the airbag device itself.

[0008] If the mass of the airbag system itself increases, the rigidity of the steering axis that supports the steering wheel needs to be increased accordingly. Furthermore, the rigidity of the tilt bracket that supports this steering axis via the steering column also needs to be increased. However, increasing the rigidity of the tilt bracket would worsen its operability, causing inconvenience to the driver.

[0009] The present invention aims to provide a steering system that can effectively dampen steering vibrations without reconstructing each of the components constituting the steering system, and without increasing the rigidity of these components. [Means for solving the problem]

[0010] The present invention relates to a steering device comprising a steering shaft to which a steering wheel is fixed at the end of the shaft, a steering column that rotatably supports the steering shaft, and a support bracket fixed to the vehicle frame and supporting the steering wheel side of the steering column, wherein the support bracket comprises a pair of opposing clamping plates that clamp both sides of the steering column, the clamping plates having a multilayer structure consisting of a plurality of steel plates stacked in the direction of clamping the steering column and a damping material interposed between each steel plate, and the clamping plates are formed with outwardly protruding beads extending in the vertical direction. [Effects of the Invention]

[0011] According to the present invention, the opposing pair of clamping plates that clamp both sides of the steering column are made of a multilayer structure consisting of multiple steel plates stacked in the direction of clamping the steering column and a damping material interposed between each of these steel plates. Furthermore, outwardly protruding beads are formed on the clamping plates with extensions in the vertical direction. As a result, when natural vibration occurs, the damping material deforms, thereby damping the vibration. Consequently, steering vibration can be effectively reduced. [Brief explanation of the drawing]

[0012] [Figure 1] Schematic side view of the steering system [Figure 2] Section II-II in Figure 1 [Figure 3] Exploded perspective view of the tilt bracket [Figure 4] Figure 3, section IV-IV [Modes for carrying out the invention]

[0013] An embodiment of the present invention will be described below with reference to the drawings. Figure 1 shows a steering device 1. The steering device 1 has a steering column 2. The steering column 2 is formed with its rear end located on the driver's side and its front end extending diagonally downward from the front of the vehicle body. The steering column 2 is formed in a cylindrical shape. The steering column 2 has a front inner column 2a and a rear outer column 2b. The rear end of the inner column 2a is axially slidable through the front end of the outer column 2b.

[0014] A clevis receiving portion 3a, provided on the clevis 3, is fixed to the upper front end of the inner column 2a. The clevis support portion 3b of the clevis 3 is fixed to the vehicle frame 4. The clevis receiving portion 3a is connected to the clevis support portion 3b via a clevis pin 3c. The steering column 2 is supported by the vehicle frame 4 via the clevis 3 so as to be able to swing up and down.

[0015] On the other hand, the outer column 2b is fixed to the steering support beam 8 via a support bracket 7. The steering support beam 8 is located within the vehicle's instrument panel (not shown). The steering support beam 8 extends horizontally to both sides in the vehicle width direction, and both ends are fixed to the vehicle body frame 4.

[0016] A steering shaft 9 is inserted into the steering column 2. The steering shaft 9 has an inner shaft 9a and an outer shaft 9b. The inner shaft 9a is inserted into the inner column 2a and is rotatably supported via a bearing (not shown). The outer shaft 9b is inserted into the outer column 2b and is rotatably supported via a bearing (not shown). The rear end of the inner shaft 9a and the front end of the outer shaft 9b are engaged by a slidable torque transmission element such as a spline.

[0017] The rear end of the outer shaft 9b protrudes from the rear end of the steering column 2 toward the driver's seat. The steering wheel (handle) 10 is fixed to the rear end of this outer shaft 9b. On the other hand, the front end of the inner shaft 9a protrudes from the front end of the steering column 2 toward the front of the vehicle body. Although not shown in the diagram, the rear end of the intermediate shaft is connected to the front end of the inner shaft 9a via a universal joint. Furthermore, the front end of the intermediate shaft is connected to the pinion shaft of the steering gearbox via a universal joint.

[0018] As shown in Figure 2, the support bracket 7 of the outer column 2b is attached to a portion where clamped portions 2c are formed on both sides in the direction perpendicular to the axis. These clamped portions 2c are formed in a state that extends downward. The side surface of these clamped portions 2c is formed to be flat. The inner surface of the clamping plate 14, which will be described later, abuts against this flat side surface. A slit 2d is formed on the lower surface of these clamped portions 2c. This slit 2d is formed along the axial direction. This slit 2d allows the inner diameter of the portion of the outer column 2b where the clamped portions 2c are formed to be elastically expandable.

[0019] The rear end portion of the inner column 2a is formed to extend toward the rear end portion of the outer column 2b beyond the position where the support bracket 7 is disposed. The support bracket 7 clamps the outer column 2b to the inner column 2a. When the outer column 2b is clamped to the inner column 2a by the support bracket 7, the front-rear position of the outer column 2b is regulated. Note that the outer shaft 9b of the steering shaft 9 moves in the front-rear direction integrally with the outer column 2b via a slidable torque transmission element.

[0020] As shown in FIGS. 2 and 3, the support bracket 7 has a mounting plate 11 and a tilt bracket (also referred to as a "column bracket") 12. The tilt bracket 12 has a top plate member 13 and a pair of opposing clamping plates 14. The clamping plates 14 have a symmetric shape. At the upper end of the clamping plate 14, a flange portion 14a bent outward in an L shape is formed. This flange portion 14a is joined to the top plate member 13 by welding or the like.

[0021] As shown in FIG. 2, in a state where the flange portion 14a of the clamping plate 14 is joined to the top plate member 13, the clamping plates 14 face each other in a parallel state. The outer surface of the clamped portion 2c formed on the outer column 2b abuts against the inner surfaces of the opposing clamping plates 14.

[0022] The top plate member 13 of this tilt bracket 12 is joined and integrated with the mounting plate 11 by welding, caulking or the like. Notch portions 11a with openings at the front of the vehicle body are formed on both sides in the vehicle width direction of this mounting plate 11. An attachment for mounting a steering support beam (not shown) is attached to and screwed into this notch portion 1a. Then, this attachment for mounting a steering support beam is fixed to the steering support beam 8 via a fastening member such as a bolt.

[0023] A tilt guide hole 14b is drilled in the clamping plate 14 of the tilt bracket 12. This tilt guide hole 14b is formed as an arc-shaped elongated hole centered on the clevis pin 3c provided in the clevis 3. Alternatively, this tilt guide hole 14b may be a straight elongated hole extending in the tangential direction of the arc centered on the clevis pin 3c.

[0024] A bolt through-hole 2e is drilled in the clamped portion 2c formed in the outer column 2b. A tilt bolt 15 is inserted through this bolt through-hole 2e. Both ends of this tilt bolt 15 protrude outward from the tilt guide holes 14b drilled in the clamping plate 14. Threaded portions 15a and 15b are screwed into both ends of this tilt bolt 15.

[0025] One of the two threaded portions 15a and 15b is a reverse thread with the same pitch. Furthermore, a square flange 15c is formed in the middle of the tilt bolt 15. This square flange 15c is embedded in one of the opposing surfaces of the slit 2d. This restricts the rotation of the tilt bolt 15.

[0026] Nuts 16a and 16b are screwed onto the threaded portions 15a and 15b of the tilt bolt 15. A tilt adjustment lever 17 is fixed to one of these nuts 16a and 16b. An operating knob 17a is fixed to the tip of this tilt adjustment lever 17. One end of an interlocking lever 18 is fixed to the other end of these nuts 16a and 16b. The other end of this interlocking lever 18 is connected to the tilt adjustment lever 17.

[0027] The clamping plate 14 has a multilayer structure (a so-called mille-feuille structure). As shown in Figure 4, the clamping plate 14 according to this embodiment has a five-layer structure. It has three thin steel plates 19a to 19c from the inner side to the outer side, with high damping materials 20a and 20b interposed between each of the thin steel plates 19a to 19c. In addition, high damping materials 20a and 20b are also interposed between each of the thin steel plates 19a to 19c in the flange portion 14a.

[0028] To avoid increasing the rigidity of the tilt bracket, the total thickness of each thin steel plate 19a-19c and the high-damping material 20a,20b must be kept equal to or less than that of a conventional product made of steel plate only. However, this does not apply if the rigidity of the damping material is low.

[0029] The high-damping materials 20a and 20b are coatings applied between the first and second thin steel sheets 19a and 19b, and between the second and third thin steel sheets 19b and 19c. The high-damping materials 20a and 20b are structural materials, for example, adhesives to which organic components with excellent damping properties have been added, thus possessing two functions: adhesion and damping.

[0030] By reducing the thickness of the first to third thin steel plates 19a to 19c and using high-damping materials 20a and 20b as coatings, the total plate thickness can be made equivalent to or less than that of conventional clamping plates. Furthermore, the clamping plate 14 may have a three-layer structure or a seven-layer or more structure, as long as the high-damping material is sandwiched between the steel plates. The thickness of the thin steel plates and the material of the high-damping material are not limited.

[0031] Furthermore, a bead 14c is formed on the clamping plate 14. As shown in Figure 3, the bead 14c is formed in a state that extends vertically in front of the tilt guide hole 14b. The bead 14c penetrates vertically through the side surface of the clamping plate 14, excluding the flange portion 14a.

[0032] As shown in Figure 4, the bead 14c is formed by overlapping the second and third thin steel plates 19b, 19c and the high-damping materials 20a, 20b and projecting outwards. The first thin steel plate 19a remains flat. By allowing the bead 14c to penetrate the clamping plate 14 in the vertical direction, the coating area of ​​the high-damping materials 20a, 20b can be increased.

[0033] Next, the operation of this embodiment with this configuration will be described. When the driver grasps the operating knob 17a of the support bracket 7 that holds the steering column 2 and pushes down the tilt adjustment lever 17, the nuts 16a and 16b separate from the tilt bolt 15. Then, the clamping pressure between the clamped portions 2c formed on both sides of the outer column 2b by the pair of clamping plates 14 provided on the tilt bracket 12 is released, and axial movement of the outer column 2b and the inner column 2a is permitted.

[0034] In this state, when the driver pulls the steering wheel 10 or pushes it forward, the outer shaft 9b moves axially together with the outer column 2b. This adjusts the fore-aft position of the steering wheel 10 relative to the driver (telescopic mechanism).

[0035] Furthermore, when the driver presses the steering wheel 10 vertically, the steering column 2 moves in the same direction around the clevis pin 3c of the clevis 3. This movement is permitted by the tilt bolt 15 moving along the tilt guide hole 14b formed in the clamping plate 14. At this time, the steering shaft 9 moves up and down together with the steering column 2, and the vertical position of the steering wheel 10 relative to the driver is adjusted (tilt mechanism).

[0036] After the steering wheel 10 has been adjusted, the driver pushes up the tilt adjustment lever 17 via the operating knob 17a, causing the nuts 16a and 16b to narrow the distance between the axes of the tilt bolts 15. This causes the pair of clamping plates 14 to press against the clamped portions 2c formed on both sides of the outer column 2b, narrowing the space between the outer column 2b and the inner column 2a. This narrowing also tightens the nuts 16a and 16b around the tilt bolts 15, fixing the positions of the steering column 2 and the steering shaft 9.

[0037] With the steering column 2 fixed in position by the support bracket 7, when the driver drives the vehicle, input from the road surface is transmitted to the tires, suspension, and body, causing the steering shaft 9 to vibrate.

[0038] When these vibrations excite the natural vibration (resonance) of the steering shaft 9, the driver holding the steering wheel 10 perceives this vibration and experiences discomfort and anxiety. As described above, vibrations from the vehicle frame 4 are transmitted to the steering column 2 via the support bracket 7. Therefore, increasing the rigidity of the support bracket 7 can reduce vibrations of the steering shaft 9.

[0039] However, the tilt bracket 12 is structured to clamp and fix the inner column 2a and outer column 2b of the steering column 2 with a clamping plate 14. Therefore, if the rigidity of the support bracket 7 is increased, the driver will need to operate the tilt adjustment lever 17 with great force when trying to use the telescopic mechanism and tilt mechanism described above, which would be inconvenient for the driver.

[0040] Incidentally, it is known that the support bracket 7 is subjected to vertical shear due to natural vibration (resonance). In this embodiment, since a bead 14c is formed on the clamping plate 14, the application area of ​​the high-damping material 20a, 20b can be increased, and the vibration due to resonance experienced by the support bracket 7 can be damped. As a result, steering vibrations transmitted to the steering wheel 10 can be effectively reduced.

[0041] Furthermore, no beads are formed on the opposing first thin steel plates 19a of the clamping plate 14. Therefore, the first thin steel plates 19a can reliably narrow the space between the clamped portions 2c formed on both sides of the outer column 2b using the entire side surface of the first thin steel plates 19A.

[0042] Furthermore, the bead 14c penetrates in the same vertical direction as the shear direction caused by the natural vibrations occurring in the steering column 2. Therefore, the high-damping members 20a and 20b can be significantly deformed in response to shear in the vertical direction. As a result, the vibrations of the steering column 2 can be efficiently damped by the deformation of the high-damping members 20a and 20b.

[0043] Furthermore, because the support bracket 7 has a structure that dampens vibrations, there is no need to re-examine the natural frequencies of the individual components that make up the steering system or to reconstruct it by increasing its rigidity, resulting in high versatility and cost-effectiveness.

[0044] Furthermore, the present invention is not limited to the embodiments described above. For example, the beads 14c formed on the clamping plate 14 may be formed in two or more rows with a predetermined interval between them. [Explanation of symbols]

[0045] 1... Steering system, 1a...notch part, 2…Steering column, 2a...Inner column, 2b... Outer column, 2c...Pinched part, 2d... slit, 2e... Bolt through hole, 3...Clevis, 3a...Clevis receiving part, 3b... Clevis support section, 3c...Clevis pin, 4…Vehicle frame, 7…Support bracket, 8…Steering support beam, 9... Steering axis, 9a... Inner axis, 9b...Outer axis, 10…Steering wheel (handle), 11…Mounting plate, 11a...notch part, 12…Tilt bracket, 13…Top panel components, 14...Holding plate, 14...bead, 14a...Flange section, 14b...Tilt guide hole, 14c...bead, 15...Tilt bolt, 15a, 15b... threaded portion, 15c... Square flange, 16a, 16b... nuts, 17...Tilt adjustment lever, 17a... Operation knob, 18... Interlocking lever, 19a~19c...1st~3rd thin steel plate, 20a, 20b… High damping material

Claims

1. A steering shaft to which the steering wheel is fixed at the end of the shaft, A steering column that rotatably supports the aforementioned steering shaft, A support bracket fixed to the vehicle frame and supporting the steering wheel side of the steering column, It has, In a steering device, the support bracket comprises a pair of opposing clamping plates that clamp both sides of the steering column, The clamping plate is The steering column has a multilayer structure consisting of multiple steel plates stacked in a direction that clamps the steering column and a damping material interposed between each of the steel plates. The clamping plate is formed with outwardly projecting beads that extend in the vertical direction. A steering device characterized by the following features.

2. The bead penetrates the clamping plate in the vertical direction. The steering device according to claim 1, characterized in that it is a steering device.

3. The damping material is a coating agent. The steering device according to claim 1, characterized in that it is a steering device.

4. The clamping plate is formed of three steel plates and the damping material interposed between each of the steel plates. The steering device according to claim 1, characterized in that it is a steering device.

5. The steel plates on the opposing surfaces of the clamping plates are not connected to the bead. The steering device according to claim 1, characterized in that it is a steering device.

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