JP5408176B2 - Manufacturing method of steering column - Google Patents

Description

  The present invention relates to an improvement in a manufacturing method of a steering column that constitutes a steering apparatus for an automobile and supports a steering shaft rotatably inside thereof.

  The steering apparatus for an automobile is configured as shown in FIG. 7, and transmits the rotation of the steering wheel 1 to the input shaft 3 of the steering gear unit 2. 4 is pushed and pulled to give a steering angle to the front wheels. The steering wheel 1 is supported and fixed at the rear end portion of the steering shaft 5, and the steering shaft 5 is rotatably supported by the steering column 6 with the cylindrical steering column 6 inserted in the axial direction. Has been. Further, the front end portion of the steering shaft 5 is connected to the rear end portion of the intermediate shaft 8 via a universal joint 7, and the front end portion of the intermediate shaft 8 is connected to the input shaft 3 via another universal joint 9. Connected to.

  With such a steering device, a tilt mechanism for adjusting the vertical position of the steering wheel 1 and a telescopic mechanism for adjusting the front-rear position according to the physique and driving posture of the driver have been widely known. ing. In order to constitute the tilt mechanism, the steering column 6 is in the width direction with respect to the vehicle body 10 (the width direction is the width direction of the vehicle body and coincides with the left-right direction. Description and claims) The same is applied to the entire range.) The rocking displacement centering on the pivot 11 installed is supported. Further, the movable bracket fixed to the rear end portion of the steering column 6 with respect to the fixed bracket 12 supported by the vehicle body 10 is vertically and longitudinally (the longitudinal direction is the longitudinal direction of the vehicle body). This is the same throughout the present specification and claims). Among these, in order to constitute a telescopic mechanism that enables displacement in the front-rear direction, the steering column 6 has a structure in which an outer column 13 and an inner column 14 are telescopically combined to expand and contract, and the steering shaft 5 The outer tube 15 and the inner shaft 16 are combined with each other so as to be able to transmit torque and expand and contract by spline engagement or the like. The illustrated example also incorporates an electric power steering device that reduces the force required to operate the steering wheel 1 using the electric motor 17 as an auxiliary power source.

  In the case of a tilt mechanism or a telescopic mechanism, the position of the steering wheel 1 can be adjusted or fixed at the adjusted position based on the operation of the adjustment lever, except for the electric mechanism. For example, in Patent Document 1, as shown in Figs. The structure to be made is described. In the case of this conventional structure, the movable bracket 22 fixed to the outer column 13a is engaged with and disengaged from the fixed bracket 12a based on the expansion / contraction of the cam device 20. Further, based on the rocking displacement of the cam member 21, whether the inner column 14a is slidable with respect to the outer column 13a is switched.

  The outer columns 13 and 13a and the inner columns 14 and 14a constituting the steering column as described above are an inner peripheral surface near the front end of the outer columns 13 and 13a, and a rear end of the inner columns 14 and 14a. The outer peripheral surface is fitted in a state where relative displacement in the axial direction is possible. When manufacturing the outer columns 13, 13a, first, the outer column main body is formed by an aluminum die casting method. Thereafter, the outer circumferential surface of the outer column main body is cut and finished. Further, the movable bracket 22 is provided separately from the outer columns 13 and 13a, and is integrally fixed by welding to a part of the outer columns 13 and 13a.

  In the case of such a steering device, the movable side bracket 22, which is a separate member, is integrally fixed to the outer columns 13 and 13 a by welding. For this reason, the strength and rigidity of the welded portion may be reduced. Also, welding is cumbersome and increases processing costs.

Therefore, Patent Document 2 describes a structure of an outer column including a column main body portion and a bulging portion corresponding to a movable side bracket, and a manufacturing method. In the case of such a structure, the column main body portion and the bulging portion are integrally formed by a hydroforming method. For this reason, strength and rigidity can be increased. In addition, because troublesome processing such as welding is not necessary, it is possible to reduce the processing cost. However, when such an outer column is manufactured by the hydroform method, a mold having a cavity having a shape along the shape of the outer peripheral surface of the outer column is used. Therefore, there is one outer column manufactured by one hydroforming process, and there is room for improvement from the viewpoint of improving production efficiency and further cost reduction.
Incidentally, there is Patent Document 3 as a publication describing a technique related to the present invention.

JP 2001-322552 A JP 2003-118595 A JP 2006-255785 A

  In view of the circumstances as described above, the present invention devised a method for manufacturing a steering column, thereby realizing a manufacturing method that can efficiently and inexpensively manufacture a steering column having a structure having excellent strength and rigidity. Invented as much as possible.

A steering column that is an object of the manufacturing method of the present invention includes a column main body portion and a bulging portion.
Column body portion of this, Ri collapsible der at least axial portion of the inner diameter, circumferential 3 or more locations of the inner peripheral surface protrudes from the inner peripheral surface radially inwardly, the outer peripheral surface A position aligned with the protruding portion in the circumferential direction is a cylindrical shape that is recessed radially inward from the outer peripheral surface.
Further, the bulging portion is formed integrally with the column main body portion, and has a pair of sandwiched portions that can be expanded and contracted in the width direction, and a pair of inclined portions.
Both of the inclined portions are continuous with the ends of the both sandwiched portions on the opposite side of the column main body, away from the column main body, and with respect to each other. It extends in the direction approaching with respect to the width direction, and the other ends of the width direction are continued through the continuous portion.

In order to produce a steering column as described above, in the manufacturing method of the present invention, an intermediate column element having a shape in which at least one end of a pair of steering columns is continuous is formed, and a hollow tube is formed radially outward by a hydroforming method. Inflate to form.
Then, by dividing the intermediate column element, a plurality of the steering column.

According to the steering column manufacturing method of the present invention configured as described above, the production efficiency of a steering column having high strength and rigidity can be improved, and the manufacturing cost can be reduced . That is, in the case of the present invention, the column main body portion and the bulging portion corresponding to the movable side bracket are integrally formed. For this reason, the strength and rigidity of the steering column can be increased. Further, an intermediate column element in which one end of at least one pair of steering columns is continuous is formed by one hydroforming process. Then, divide the intermediate column element, the steering column of the plurality (at least two). For this reason, it is possible to improve the production efficiency of the steering column and reduce the manufacturing cost .

The side view of the outer column which comprises one example of the reference example relevant to this invention which comprises the steering column used as the object of this invention. FIG. 3 is a cross-sectional view of a tilt / telescopic steering apparatus incorporating an outer column that constitutes a steering column that is the subject of the present invention. Similarly, a side view (A) of the intermediate column element and a side view (B) showing a state in which the intermediate column element is divided. The figure similar to FIG. 1 which shows an example of embodiment of this invention . Similarly, the same figure as FIG. Similarly, the same figure as FIG. The partial cutaway side view which shows an example of the steering device for motor vehicles incorporating the tilt and telescopic steering device. Vertical side view showing a first example of a conventionally known telescopic steering device In Figure 8, X-X sectional view.

[ One Reference Example Related to the Present Invention ]
1 to 3 show an example of a reference example related to the present invention . Part of the features of the present invention, including this reference example , is that the method for manufacturing the steering column has been devised. In addition to the telescopic mechanism for adjusting the front / rear position of the steering wheel 1 (see FIG. 7), the steering column that is the object of the manufacturing method of the present invention is similar to the structure shown in FIGS. It can also be applied to a structure having a tilt mechanism for adjusting the vertical position. Further, a manufacturing method of a steering column incorporated in a steering apparatus that is not provided with either a telescopic mechanism or a tilt mechanism is also an object of the present invention.

Moreover, the structure of the telescopic mechanism incorporating the steering column and the tilt mechanism, which is the object of the manufacturing method of the present invention, includes the structures shown in FIGS. Since the structure is substantially the same as that of the first embodiment, the illustration and description of the portions that are configured in the same manner as in the prior art will be omitted or simplified, and the characteristic portions of this reference example will be mainly described below.

The steering apparatus incorporating the steering column that is the object of the manufacturing method of the present reference example is similar to the steering apparatus having the conventional structure described above, the steering shaft 5, the steering column 6a, the fixed side bracket 12b, the hook-shaped member 19, and the like. The adjusting lever 18 and the pivot 11 (see FIGS. 7 and 8) are provided.
Among these, the steering shaft 5 is mounted with the steering wheel 1 at a rear end portion, and is rotatably supported in the steering column 6a.

  The steering column 6a includes an outer column 13b and an inner column 14b. The steering column 6a has an outer column 13b as an upper column on the steering wheel 1 (see FIG. 7) side and an inner column 14b on the side far from the steering wheel 1 in the same manner as the structure shown in FIGS. The lower column.

The outer column 13 b includes a column main body portion 26 and a bulging portion 27.
Of these, the column main body 26 has a cylindrical shape in which at least a part of the inner diameter in the axial direction can be expanded and contracted by elastic deformation.
Further, the bulging portion 27 is integrally formed with the column main body portion 26 and is hung from one axial end portion (left end portion in FIG. 1) of the outer peripheral surface of the column main body portion 26 to the radially outer side (see FIG. 1). 1 (under 1). The bulging portion 27 corresponds to the movable bracket 22 (see FIGS. 8 to 9) constituting the telescopic steering device having the conventional structure described above.

Such a bulging portion 27 has a pair of sandwiched portions 25, 25 and a bottom portion 28.
Of these, both of the sandwiched portions 25, 25 are connected to a pair of ends of the upper semi-cylindrical portion of the outer column 13b (the left-right direction in FIG. 2), and constitute a pair of fixed side brackets 12b described later. The support plate portions 30 and 30 are formed substantially in parallel. Moreover, it is clamped by these both support plate parts 30 and 30, and the expansion / contraction about the width direction is possible. Furthermore, a pair of column-side through holes 31 and 31 that are long in the axial direction are formed in both of the sandwiched portions 25 and 25.
The bottom portion 28 is continuous with the other ends (lower end portions in FIG. 2) of the sandwiched portions 25, 25.

  The outer column 13b is a hydroforming method in which a hydraulic pressure (for example, a water pressure) is applied to the inner peripheral surface of a metal tube that is a hollow member made of a steel plate or an aluminum alloy, and the metal tube is plastically deformed radially outward. It is formed by.

In particular, in the case of this reference example , in a mold having a cavity having an inner surface shape corresponding to the outer surface shape of the intermediate column element 29 having a shape in which one end portions of a pair of outer columns as shown in FIG. The metal tube which is a material is set. Then, both ends of the metal tube are closed with a shaft pushing tool or the like, and a high hydraulic pressure is applied to the metal tube. By applying this hydraulic pressure, the intermediate column element 29 is formed by expanding the diameter of the metal tube radially outward until it is in close contact with the inner surface of the cavity of the mold. In addition, the column side through-holes 31 of the bulging part 27 can also be formed by a hydroforming method (see Patent Document 3).
Next, as shown in FIG. 3B, the intermediate column element 29 is cut at an axial intermediate portion α {see FIG. 3A} to form two outer columns 13b and 13b. In the case of this reference example , the intermediate column element 29 has a shape in which two outer columns are continuous. However, in consideration of the balance between the cost of the mold and the like, and the processing cost, three or more outer columns are used. It is also possible to form an intermediate column element having a shape such that the columns are continuous and to divide the intermediate column element into three or more outer columns .
Further, the structure of the inner column 14b is the same as a conventionally known structure, and thus the description thereof is omitted.

  The fixed side bracket 12b is provided at a fixed part of a vehicle body or the like (see FIG. 7), and sandwiches a part of the outer column 13b where the inner diameter can be expanded and contracted from both sides in the width direction. A pair of support plate portions 30 and 30 are provided. Also, vertically long holes 39, 39 each having a partial arc shape centering on the central axis of the pivot 11 are formed at positions where the support plate portions 30, 30 are aligned with each other.

  In addition, the bowl-shaped member 19 is inserted through the vertical elongated holes 39, 39 of the both support plate portions 30, 30, and the column side through holes 31, 31 of the sandwiched portions 25, 25, It is arranged in the width direction. Moreover, the head 32 which is a press part is provided in the end (left end of FIG. 2) of this bowl-shaped member 19. As shown in FIG. And the holding nut which is a pressing member in the part which protruded from the outer side surface (right side surface of FIG. 2) of the support plate part 30 of the said fixed side bracket 12b in the other end (right side of FIG. 2) of this bowl-shaped member 19 33 is screwed together. Further, the base end portion of the adjusting lever 18 is coupled and fixed to the holding nut 33. Therefore, if the holding nut 33 is rotated based on the operation of the adjusting lever 18 and the interval in the width direction between the holding nut 33 and the head portion 32 is changed (expanded / reduced), the two support plate portions 30, The interval between 30 can be enlarged or reduced. In addition, the structure shown in FIGS. 7-9 mentioned above can also be employ | adopted for the structure for adjusting the space | interval of such both said support plate parts 30 and 30. FIG.

  When adjusting the position of the steering wheel 1 in the front-rear direction, the adjustment lever 18 is rotated in a predetermined direction to widen the interval in the width direction between the holding nut 33 and the head 32. Then, the distance between the inner surfaces of the pair of support plate portions 30, 30 of the fixed side bracket 12 b is elastically expanded, and both the inner surfaces of both the support plate portions 30, 30 and both the covering portions of the bulging portion 27 are covered. The surface pressure of the contact part with the outer surface of the clamping parts 25, 25 is reduced or lost. Along with this, the surface pressure of the fitting portion between the inner peripheral surface of the outer column 13b and the outer peripheral surface of the inner column 14b is reduced or lost, and the outer column 13b and the inner column 14b are moved in the axial direction ( It becomes a state in which relative displacement is possible in the front-rear direction). As a result, the position of the steering wheel 1 in the front-rear direction can be adjusted.

On the other hand, when the position of the steering wheel 1 in the vertical direction is adjusted, the saddle member 19 is moved in the vertical direction with the adjusting lever 18 rotated in a predetermined direction as described above. by displacing the inside 39 allows vertical swinging displacement centered on the pivot axis 11.

  Further, after the position adjustment, if the adjusting lever 18 is rotated in the direction opposite to the predetermined direction, the interval in the width direction between the holding nut 33 and the head 32 is reduced. Then, the space | interval of the inner surface of both said support plate parts 30 and 30 shrinks, and the surface pressure of the contact part of the inner surface of these both support plate parts 30 and 30 and the outer surface of both said clamping parts 25 and 25 is carried out. Becomes larger. Accordingly, the surface pressure of the fitting portion between the inner side surface of the outer column 13b and the outer peripheral surface of the inner column 14b increases. As a result, the steering wheel 1 is supported at the adjusted position.

In the telescopic mechanism of this reference example , as described above, the outer column 13b is an upper column on the steering wheel 1 (see FIG. 7) side, and the inner column 14b is a lower column on the side far from the steering wheel 1. However, the present invention is not limited to such a configuration, and the outer column can be a lower column and the inner column can be an upper column. In this case, the shape of the column side through-hole of the bulging portion constituting the outer column is not a long hole that is long in the axial direction, but a round hole through which the bowl-shaped member can be inserted.

  Further, the steering column that is the subject of the present invention can also be applied to a steering device having a structure that does not constitute a telescopic mechanism. Also in this case, the shape of the column side through hole of the bulging portion constituting the outer column is not a long hole that is long in the axial direction, but a round hole through which the bowl-shaped member can be inserted.

In the case of this reference example as described above, first, the intermediate column element 29 {see FIG. 3 (A)} having a shape in which one end portions of the pair of outer columns 13b are continuous is formed by a hydroforming method. The intermediate column element 29 is divided into two outer columns 13b and 13b {see FIG. 3B}. For this reason, an outer column with high rigidity can be manufactured efficiently and at low cost . That is, the column main body portion 26 and the bulging portion 27 corresponding to the movable bracket are integrally formed by a hydroforming method. For this reason, rigidity can be made high compared with the structure which couple | bonded the outer column and the movable side bracket integrally by welding. In addition, since two outer columns can be formed in one hydroforming process, production efficiency can be improved. Furthermore, since a troublesome process such as welding is unnecessary , the manufacturing cost can be reduced.

[ Example of Embodiment ]
4 to 6 show an example of an embodiment of the present invention. The outer column 13c that constitutes the steering column that is the subject of this example includes a column main body portion 26a and a bulging portion 27a, as in the above-described example of the reference example .
Of these, the column main body 26a has a cylindrical shape in which at least a part of the inner diameter in the axial direction can be elastically expanded / contracted. Further, the inner peripheral surface of the column main body portion 26a has a support portion 34 for fitting and supporting the inner column 14b on the inner diameter side of the column main body portion 26a so as to be capable of axial displacement.

The support portions 34 are radially inward from the inner peripheral surface of the inner peripheral surface of the outer column 13c at three positions at equal intervals in the circumferential direction of the portion overlapping the inner column 14b in the axial direction. It consists of ridges 35, 35 formed in a protruding state. Further, in the outer peripheral surface of the outer column 13c, concave portions 36, 36 that are recessed radially inward from the outer peripheral surface are formed at positions that align with the raised portions 35, 35 in the circumferential direction. And the front-end edge (radial direction inner side edge) of these each protruding parts 35 and 35 is contact | abutting with the outer peripheral surface of the said inner column 14b. In addition, from the viewpoint of reliably abutting the tips of the raised portions 35, 35 to the outer peripheral surface of the inner column 14b without increasing the processing accuracy of the raised portions 35, 35 constituting the support portion 34. The number of the raised portions 35 is preferably 3 in this example. However, the number of the raised portions 35 can be more than three in consideration of the balance of processing cost and the like.
The positions where these raised portions 35 are formed are not limited to the circumferentially equidistant positions on the inner peripheral surface of the outer column 13c. However, it is not biased toward the semicircular side, but is distributed in a range exceeding the semicircular circumference.

Further, the bulging portion 27a is integrally formed with the column main body portion 26a so as to be hung from one axial end portion (left end portion in FIG. 4) of the outer peripheral surface of the column main body portion 26a to the radially outer side (see FIG. 4). 4 is formed in a state of projecting downward (below 4).
Such a bulging portion 27 a includes a pair of sandwiched portions 25 a and 25 a that can be expanded and contracted in the width direction, and a pair of inclined portions 37 and 37.

  Of these, both sandwiched portions 25a, 25a are connected at one end to the lower ends of the raised portions 35, 35 formed in the lower part of FIG. 5 among the raised portions 35, 35 of the outer column 26a, The pair of support plate portions 30 and 30 constituting the fixed side bracket 12b are formed substantially parallel to each other. Further, column-side through holes 31 and 31 that are long in the axial direction are formed at positions where the both sandwiched portions 25a and 25a are aligned with each other.

Further, both the inclined portions 37, 37 are connected at one end to the other ends of the sandwiched portions 25a, 25a so as to approach each other in the width direction (left-right direction in FIG. 5) (inclined in FIG. 5). downward) extending, respective other ends are continuous through the continuous section 38.

In the case of the outer column 13c of this example, compared to the outer column 13b of the example of the reference example described above , both inclined portions 25a, 25a of the bulging portion 27a and both support plate portions 30, 30 of the fixed side bracket 12b. However, the angle formed by the direction (left-right direction in FIG. 5) of pressing (clamping) the clamped portions 25a, 25a is increased. For this reason, the outer column 13c of this example has low rigidity in the width direction of both of the sandwiched portions 25a and 25a as compared to the outer column 13b of the example of the reference example described above . As a result, the operability of the adjustment lever 18 can be stabilized, and a stable support rigidity (clamping force) can be imparted to the inner column 14b.

Such outer column 13c (including the supporting portion 34), the above-described similar to the example of the reference example, the shape which is continuous with one end portions of the outer column 13c of a pair, such as shown in FIG. 6 (A) A metal tube as a material is set in a mold having a cavity having an inner surface shape that matches the outer surface shape of the intermediate column element 29a. Then, both ends of the metal tube are closed with a shaft pushing tool or the like, and a high hydraulic pressure is applied to the metal tube. By applying the hydraulic pressure, the diameter of the metal tube is expanded outward in the radial direction until it is in close contact with the inner surface of the cavity of the mold, thereby forming the intermediate column element 29a.
Then, the intermediate column element 29a as shown in FIG. 6 (B), cut in the middle portion axially alpha {FIG 6 (A) see}, two outer column 13c, and 13c.
In addition, after the intermediate column element 29a is divided and the outer column 13c is formed, cutting or pressing may be performed on the tip portions of the raised portions 35 and 35 constituting the support portion 34. Other structures, functions, and effects are the same as those of the reference example described above .

One example of the reference example and one example of the embodiment described above have been described with respect to a steering device having a tilt mechanism for adjusting the vertical position of the steering wheel and a telescopic mechanism for adjusting the front-back position. . However, the present invention can also be applied to a structure of a steering device provided with either one of a tilt mechanism or a telescopic mechanism, or a structure of a steering device not provided with any mechanism.
Further, the front-rear direction of the outer column and the inner column constituting the steering column is not limited. The inner column may be on the rear side, and the outer column may be on the rear side.

DESCRIPTION OF SYMBOLS 1 Steering wheel 2 Steering gear unit 3 Input shaft 4 Tie rod 5 Steering shaft 6, 6a Steering column 7 Universal joint 8 Intermediate shaft 9 Universal joint 10 Car body 11 Axis 12, 12a, 12b Fixed side bracket 13, 13a, 13b, 13c Outer column 14, 14a, 14b Inner column 15 Outer tube 16 Inner shaft 17 Electric motor 18 Adjustment lever 19 Hook-shaped member 20 Cam device 21 Cam member 22 Movable bracket 23, 23a Raised portion 24 Support claw portion 25, 25a Clamped portion 26, 26a Column body 27, 27a Bump 28 Bottom 29, 29a Intermediate column element
Reference Signs List 30 Support plate portion 31 Column side through hole 32 Head 33 Holding nut 34 Support portion 35 Raised portion 36 Recessed portion 37 Inclined portion 38 Continuous portion 39 Vertically long hole

Claims (1)

At least a part of the inner diameter in the axial direction can be enlarged / reduced , and three or more circumferential directions of the inner peripheral surface protrude radially inward from the inner peripheral surface. A cylindrical column main body portion whose position aligned in the direction is recessed radially inward from the outer peripheral surface, and a pair of sandwiched portions formed integrally with the column main body portion and capable of expanding and contracting in the width direction And a bulging portion having a pair of inclined portions, of which both inclined portions are connected to the ends of the both sandwiched portions opposite to the column main body portion, and A method of manufacturing a steering column that extends in a direction away from the column main body and in a direction approaching each other with respect to the width direction of the column main body, and the other ends of the column are continuous via a continuous portion,
After forming an intermediate column element having a shape in which at least one pair of steering columns is continuous with each other, a hollow tube is expanded radially outward by a hydroforming method,
A method for manufacturing a steering column, wherein the intermediate column element is divided into a plurality of the steering columns.

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