JP2006182089A - Steering column - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a tilt lever for mainly reducing an operation force of the tilt lever while securing an axial force of a fastening bolt, and also realizing an anti-rust treatment. <P>SOLUTION: This steering column 2 comprises a tilt mechanism for connecting a vehicle body side upper bracket 25 fixed on a vehicle side with a column side upper bracket 26 fixed to a column jacket 22 by a fastening bolt 11, and switching a holding condition for fastening the vehicle side upper bracket 25 and the column side upper bracket 26 with the fastening bolt 11 to a release condition for loosening them by a rotary operation of the tilt lever 1 fitted to the fastening bolt 11. In this steering column, a manganese phosphate film is formed on the tilt lever 1 at least at a portion slide-contacting the vehicle side upper bracket 25. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a steering column provided with a tilt mechanism that is pivotally attached to a vehicle body by a lower tilt shaft and connected to the vehicle body by an upper tightening bolt.

  In recent years, many steering columns are provided with a tilt mechanism that is attached to the vehicle body by a lower tilt shaft and is connected to the vehicle body by an upper tightening bolt. Specifically, the column side lower bracket fixed to the vehicle body side lower bracket fixed to the vehicle body and the column side lower bracket fixed to the column jacket are fixedly attached to the vehicle body side upper bracket fixed to the vehicle body side. The side upper bracket is connected by a fastening bolt to which a tilt lever that is in sliding contact with the vehicle body side upper bracket is attached to constitute a tilt mechanism.

  In this tilt mechanism, when the tilt lever is rotated to one side, the axial force of the tightening bolt increases, thereby tightening the vehicle body side upper bracket and the column side upper bracket and fixing the position of the column jacket to which the column side upper bracket is fixed. . Further, when the tilt lever is rotated to the other side, the axial force of the tightening bolt decreases, so that the vehicle body side upper bracket and the column side upper bracket are loosened, and the column jacket to which the column side upper bracket is fixed is made swingable. .

  The tilt lever has a portion that directly or indirectly slidably contacts, and it is sufficient that the axial force of the tightening bolt can be increased or decreased by a turning operation. For example, in Patent Document 1, a cam member is provided on the tilt lever, and the pressing amount of the cam member against the tightening bolt is adjusted by turning. In Patent Document 1, at least the cam sliding contact surface of the tilt lever or the cam member is coated with a low friction material such as Teflon (registered trademark) or molybdenum, and the friction characteristic of sliding on the cam sliding contact surface of the tilt lever is provided. The operation force of the tilt lever (force required for rotation) is reduced. Thereby, the operation force of the tilt lever can be reduced while securing the axial force of the tightening bolt.

JP 2000-302048

  As seen in Patent Document 1, in order to reduce the operating force of the tilt lever while securing the axial force of the tightening bolt, the coating of the low friction member is preferable. However, Patent Document 1 only mentions Teflon (registered trademark) or molybdenum as a specific coating material, and does not specify a specific coating method. Here, the tilt lever is painted or plated for the purpose of rust prevention. However, in Patent Document 1 in which a specific coating method is not specified, can it be used together with such painting or plating for the purpose of rust prevention? Whether or not is unknown. Since the tilt lever is in the vehicle, the possibility of rusting is low, but rust prevention treatment is still indispensable.

  Painting or plating the tilt lever is another problem. For example, in the case of coating, the film thickness tends to be as thick as 20 μm or more, and the design of the tilt lever must take into account the film thickness. However, if the tilt lever is rotated repeatedly, the paint is peeled off, and as the paint peels off, the increase or decrease in the axial force of the tightening bolt due to the rotation of the tilt lever changes, and sufficient axial force is obtained. The possibility of disappearing comes out. Further, in the case of plating, plating with hexavalent chromium is usually performed, but from the viewpoint of environmental protection in recent years, it has become difficult to use hexavalent chromium. Therefore, we studied to develop a tilt lever that achieved anti-rust treatment while focusing on reducing the operating force of the tilt lever while securing the axial force of the tightening bolt.

  As a result of the study, the product developed was that the vehicle body side upper bracket fixed to the vehicle body side and the column side upper bracket fixed to the column jacket were connected by a tightening bolt, and the tilting lever attached to the tightening bolt was operated to rotate the vehicle body. In a steering column equipped with a tilt mechanism that switches between a holding state in which the side upper bracket and the column side upper bracket are tightened by tightening bolts and a release state in which the column side upper bracket is loosened, the tilt lever forms a manganese phosphate film at least in a portion that is in sliding contact with the vehicle body side upper bracket This is a steering column.

  More specifically, the column side lower bracket fixed to the column jacket is fixed to the vehicle body side lower bracket fixed to the vehicle body by the tilt shaft, and the vehicle side upper bracket fixed to the vehicle body side is fixed to the column jacket. The column side upper bracket is connected by a tightening bolt with a tilt lever attached in sliding contact with the vehicle body side upper bracket. When the tilt lever is rotated to one side, the axial force of the tightening bolt increases, thereby the vehicle body side upper bracket. And the column side upper bracket is tightened, and the column jacket to which the column side upper bracket is fixed is put into a holding state, and when the tilt lever is rotated to the other side, the axial force of the tightening bolt is reduced. Column side upper bracket In a steering column equipped with a tilt mechanism that releases the arm and releases the column jacket to which the column-side upper bracket is fixed, the tilt lever has a manganese phosphate coating on at least the portion that comes into sliding contact with the body-side upper bracket. It is the formed steering column.

  In the tilt lever according to the present invention, the manganese phosphate coating is formed at least on the part that comes into sliding contact with the vehicle body upper bracket, thereby reducing the frictional resistance of the part that comes into sliding contact and ensuring the axial force of the tightening bolt. Improve sex. Manganese phosphate coating is a very thin coating of about 2μm to 10μm that can be formed by simple surface treatment compared to normal plating, and it can be formed by chemical treatment that does not use electric current, so the treatment site has a complicated shape. However, there is an advantage that it is easy to obtain a uniform thickness and there is no need to worry about dimensional changes due to the film thickness before and after processing. In addition, since the processing temperature does not normally exceed 100 ° C., there is no risk of physical change in the material of the tilt lever. In addition, since the manganese phosphate coating is an electrical non-conductor, it is no different from having been subjected to rust prevention treatment. Accordingly, the manganese phosphate film is preferably formed on the entire tilt lever. By forming a manganese phosphate film on the entire tilt lever, it becomes possible to form a manganese phosphate film on a large number of tilt levers at once without performing a masking process or the like, thereby facilitating batch processing.

  According to the present invention, not only can the operating force of the tilt lever be reduced while securing the axial force of the tightening bolt, but also the rust prevention treatment can be performed at the same time. Further, the conventional tilt lever has been darkly colored so as to be inconspicuous, specifically black or a similar color, but the manganese phosphate film has a rich metallic color. A tilt lever colored in black or a similar color can be provided. In addition, the present invention is not limited to the improvement of the tilt lever alone, and by using a manganese phosphate film that can be formed thinly and uniformly, there is an advantage that the film thickness does not need to be considered in the design, and in particular, the phosphoric acid is applied to the entire tilt lever. If a manganese film is formed, there is also an advantage that productivity can be improved so that a large number of tilt levers can be processed at one time.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. 1 is a side view showing an example of a steering column 2 to which a tilt lever 1 of the present invention is applied, FIG. 2 is a cross-sectional view taken along the line AA in FIG. 1 (the steering shaft is not shown), and FIG. 4 is an end view taken along line BB in FIG. 3, FIG. 5 is a plan view of the tilt lever 1, and FIG. 6 is a front view of the tilt lever 1. The tilt lever 1 of this example is an example in which the axial force of the tightening bolt 11 is adjusted by changing the screwing position of the tightening nut 12 by rotating the tilt lever 1 with respect to the tightening bolt 11 that cannot rotate.

  First, the steering column 2 to which the tilt lever 1 is attached will be described. As shown in FIGS. 1 and 2, the steering column 2 of the present example has a column-side lower bracket 23 fixed to a column jacket 22 and a column-side lower bracket 23 fixed to a vehicle body side fixed to a vehicle body by a tilt shaft 24. The column side upper bracket (support bracket) 26 fixed to the column jacket 22 is connected to the vehicle body side upper bracket 25 fixed to the vehicle body side by the fastening bolts 11 to which the tilt lever 1 slidably contacting the vehicle body side upper bracket 25 is attached. ing. A steering (not shown) is attached to a steering shaft 27 extending in the left direction in FIG.

  The vehicle body side upper bracket 25 is provided with a hanging bracket 254 having a U-shaped cross section provided with a pair of right and left lifting grooves 253 and 253 for mounting the tightening bolt 11 so as not to rotate on a one-way bracket 252 having a pair of left and right mounting portions 251 and 251 to the vehicle body. It is fixed and configured. The tightening bolt 11 has a restriction block 111 that fits into the lifting groove 253 on the bolt head 112 (see the enlarged side surface portion in the chain line in FIG. 2), and can be displaced in the extending direction of the lifting groove 253. It is regulated so that it cannot rotate. The column-side upper bracket 26 is fixed to the lower surface side of the column jacket 22 and is fitted inside the suspension bracket 254 so that the tightening bolt 11 is passed therethrough.

  The tilt lever 1 is externally fitted to the screw portion 113 of the tightening bolt 11 protruding from the lifting groove 253 of the suspension bracket 254, and is screwed to the screw portion 113 of the tightening bolt 11 via the stopper plate 13 fixed to the tilt lever 1. It is integrated with the fastening nut 12 to be worn. The tightening nut 12 holds the tilt lever 1 together with the suspension bracket 254 to generate the axial force of the tightening bolt 11. The stopper plate 13 is fixed to the fastening nut 12 and has an arcuate groove 131 centered on the fastening bolt 11. The stopper plate 13 is fixed to the tilt lever 1 by a fixing nut 141 screwed into the fixing bolt 14 by passing a fixing bolt 14 protruding from the tilt lever 1 through the arc-shaped groove 131. Thus, the axial force generated by the depression of the tilt lever 1 can be adjusted depending on the position of the arc-shaped groove 131 where the stopper plate 13 is fixed.

  The tilt lever 1 of this example increases or decreases the axial force of the tightening bolt 11 by changing the screwing position of the tightening nut 12 that rotates together with the stopper plate 13 to the tightening bolt 11. For example, when the tilt lever 1 is pushed down to be held, the tightening nut 12 is tightened to the tightening bolt 11, the axial force of the tightening bolt 11 is increased, and the suspension bracket 254 and the column side upper bracket 26 are pressed against each other. Thus, the column jacket 22 is held by the suspension bracket 254. Further, when the tilt lever 1 is lifted and released, the tightening nut 12 is loosened from the tightening bolt 11, the axial force of the tightening bolt 11 is reduced, and the suspension bracket 254 and the column side upper bracket 26 are loosened. The column jacket 22 can be swung around the tilt shaft 24 within a range in which the tightening bolt 11 is restricted by the lifting groove 253 of the hanging bracket 254.

  As shown in FIGS. 3 to 6, the tilt lever 1 of this example includes a shaft attachment surface 15, a bending surface 16, and an operation surface 17 formed by bending a single original plate. Since only the contact surface 15 is in contact, the manganese phosphate coating 3 (see FIG. 4) may be formed on at least the inner surface of the contact surface 15. However, since the manganese phosphate film 3 also has a function of preventing rust and coloring, in this example, the manganese phosphate film 3 is formed on the entire tilt lever 1. Since this manganese phosphate film 3 can be made very thin, the film thickness t is set to 2 μm to 10 μm, preferably 4 μm to 7 μm so as not to be affected by the design value. Further, the surface roughness of the manganese phosphate coating 3 is set to 6 μm to 8 μm, preferably 3 μm to 4 μm, and the crystal grain size constituting the manganese phosphate coating 3 is set to 6 μm to 8 μm, preferably 3 μm to 4 μm. The frictional resistance inside the shaft attachment surface 15 is reduced, and only the operating force of the tilt lever 1 can be reduced without impairing the axial force of the tightening bolt 11.

  The tilt lever 1 of this example is provided with a resin grip 18 by insert molding on the operation surface 17. The manganese phosphate coating 3 of the present invention also has an advantage that it is easy to provide a resin grip 18 by such insert molding. For example, when coating is performed after resin grip molding, masking is required for the resin grip, which causes a problem of reducing production efficiency. Moreover, when painting before resin-made grip shaping | molding, when molding a resin-made grip, there exists a possibility that a coating surface may be damaged. In this regard, the plating treatment does not cause a problem associated with the coating, but the hexavalent chrome plating usually used for the tilt lever cannot be used from the viewpoint of environmental problems. On the other hand, the tilt lever 1 of the present invention has no fear that the manganese phosphate coating 3 may be damaged even if the resin grip 18 is provided by insert molding after the manganese phosphate coating 3 is formed. Do not invite. Thus, it can be seen that the manganese phosphate coating 3 of the present invention is excellent even when the tilt lever 1 is processed.

  Next, for the tilt lever according to the present invention, the relationship between the operation force of the tilt lever and the holding force of the column jacket was measured. Since the axial force of the tightening bolt appears as the holding force of the column jacket (the force that holds the posture without slipping), the holding force of the column jacket was measured as a characteristic closer to the actual machine.

  The tilt levers of the examples and comparative examples are both made of hot-rolled mild steel and have the same shape. However, in the examples, a manganese phosphate film is formed on the entire tilt lever, and in the comparative example, hexavalent chromium is formed on the entire tilt lever. It is plated.

  The holding power of the column jacket was measured as follows. First, the tilt lever of the example or the comparative example is attached to the fastening bolt of the steering column, and the vehicle body side upper bracket (one-way bracket in the above example) is fixed to the jig. Then, a rigid jig is connected to the steering shaft protruding from the column jacket, and a load is applied to the rigid jig from the upper side in the swing direction of the column jacket (side where the steering is pressed). If the column jacket moves due to this load, the load just before the movement becomes the holding force of the column jacket.

  The tilt levers of the examples and comparative examples are in a position where rotation is stopped at each load by applying a load in the range of 30N to 80N in 10N increments from the released state (the state in which the column jacket can freely swing). The above measurement is carried out. The load is an operation force, and the load on the column jacket measured at a position where the tilt lever is stopped by applying each load is a holding force corresponding to the operation force.

  The test results are shown in FIG. Since the horizontal axis is the tilt lever operating force and the vertical axis is the column jacket holding force, the higher the graph line is located, the higher the holding force can be obtained, that is, the better. . From this, the embodiment in which a holding force of about 25% is obtained with the same operating force is superior to the comparative example, and the holding force of the column jacket is usually given as a design requirement, so the design requirement is satisfied. It can be seen that the tilt lever that generates the holding force can be operated more easily than in the past.

It is a side view showing an example of the steering column to which the tilt lever of the present invention is applied. It is AA sectional drawing in FIG. It is a side view of a tilt lever. It is a BB end elevation in FIG. It is a top view of a tilt lever. It is a front view of a tilt lever. It is a graph showing the relationship between the operation force of each tilt lever and the holding force of a column jacket of an Example and a comparative example.

Explanation of symbols

1 Tilt lever
11 Tightening bolt
12 Tightening nut
13 Stopper plate
14 Fixing bolt
15 Axial surface
16 Bending surface
17 Operation surface
18 Resin grip 2 Steering column
21 Vehicle side lower bracket
22 Column jacket
23 Column side lower bracket
24 Tilt axis
25 Body side upper bracket
26 Column side upper bracket (support bracket)
3 Manganese phosphate coating

Claims (2)

The vehicle body side upper bracket and the column side upper bracket are connected to each other by connecting the vehicle body side upper bracket fixed to the vehicle body side and the column side upper bracket fixed to the column jacket with a tightening bolt, and rotating the tilt lever attached to the tightening bolt. A steering column having a tilt mechanism that switches between a holding state in which a bolt is tightened by a tightening bolt and a releasing state in which the bolt is tightened, wherein the tilt lever has a manganese phosphate film formed at least on a portion that is in sliding contact with the upper bracket on the vehicle body . The steering column according to claim 1, wherein the tilt lever has a manganese phosphate film formed on the whole.

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