JP2015174508A - Seal structure of vehicle steering device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a structure capable of preventing a seal part from being wound when fitted to a dash panel, and improving sealability without any increase in the size or weight of a grommet.SOLUTION: In a third shaft component 3a penetrating a dash panel 4, a part of which is adjacent to the dash panel at the side of an engine room R1 is covered by a grommet 6, and the grommet 6 is pressed into contact with the dash panel 4. A seal part 12 is formed at one end of a trunk 11 of the grommet 6, and an attachment stem 13 fixed to a third shaft component 3c is formed at the other end thereof. A neck part 14 having a constricted shape formed in an axially intermediate part of the trunk 11 is also formed concentrically with a neck part center line C2 inclined at a predetermined angle with respect to an axis C of the trunk 11.

Description

  TECHNICAL FIELD The present invention relates to a seal structure for a steering device for a vehicle, and in particular, a portion of a steering shaft arranged so as to penetrate a dash panel that separates a vehicle compartment from an engine room, close to the dash panel on the engine room side. The present invention relates to a seal structure for a vehicle steering apparatus that is covered with a “hole cover” or the like.

  As a seal structure of this type of vehicle steering device, one described in Patent Document 1 has been proposed. In the seal structure described in Patent Document 1, in a grommet having a flexible part in the middle part in the longitudinal direction (axial direction), the grommet projects outwardly on the outer peripheral side of the seal part that contacts the dash panel and is assembled. When the outer stopper part that does not contact the dash panel in the state is formed and a part of the inner peripheral side of the seal part is dragged in the assembling direction when it is assembled, The portion is brought into contact with the dash panel so that the entrainment of the seal portion is suppressed.

JP 2011-79473 A

  However, in the technique described in Patent Document 1, it is necessary to provide the outer stopper portion with a certain degree of rigidity in order to suppress the entrapment of the seal portion by the outer stopper portion coming into contact with the dash panel during assembly. . For this reason, an increase in volume and weight required for the outer stopper portion causes undesirably increasing the size and weight of the entire grommet.

  Moreover, in the technique described in Patent Document 1, the degree of freedom of flexure deformation of the flexible portion set in the middle portion in the longitudinal direction of the grommet is set based on the axial direction of the grommet itself, and the grommet is displayed on the dash panel. In assembling, the assembling direction which must be a direction inclined by a predetermined angle with respect to the axis of the grommet is not sufficiently considered. Therefore, depending on the setting of the outer stopper portion, there is still a possibility that the seal portion will be caught.

  The present invention has been made paying attention to such a problem, and without entailing enlarging the grommet and increasing the weight, prevents the seal portion from being caught when assembled to the dash panel, thereby preventing watertightness. The present invention is intended to provide a seal structure for a vehicle steering device that improves the sealing performance such as the performance and sound insulation.

  As described above, the present invention covers a portion of the steering shaft that is disposed so as to penetrate the dash panel that separates the passenger compartment and the engine room from the grommet on the engine room side and close to the dash panel. This is a seal structure for a vehicle steering device in which the grommet is sealed by being brought into pressure contact with the dash panel. In addition, the grommet has a mounting base in which a seal portion that presses against the dash panel is fixed to a steering shaft-related component at the other end of the cylindrical body portion at one end of the cylindrical body portion that is externally attached to the steering shaft. Are formed, and a neck portion having a constricted shape that can be easily deformed is formed at an intermediate portion in the axial direction of the trunk portion, and the neck portion is inclined at a predetermined angle with respect to the axial center of the trunk portion. It is characterized by being formed concentrically with the neck center line with respect to the center line.

  In this case, when the steering shaft is assembled at a predetermined position after the grommet is attached to the steering shaft on the engine room side in the same manner as the technique described in Patent Document 1, for example, interference with the vehicle body or other parts In some cases, for example, the steering shaft assembly direction from the engine room side is restricted, and the grommet seal portion has to be assembled from an oblique direction rather than a direction perpendicular to the dash panel. For this reason, the neck portion center line inclined at a predetermined angle with respect to the axis of the trunk portion is assumed to be the assembly direction from the oblique direction of the grommet with respect to the dash panel. The grommet itself is made of, for example, a rubber-based flexible material.

  And since the said neck part functions as what is called a deformation | transformation easy part in the axial center direction intermediate part of the trunk | drum in a grommet, both the inner and outer peripheral surfaces of a neck part are as described in Claim 2. It is desirable to have a constricted shape and a thin-walled shape compared to other parts.

  Further, according to the function of the seal portion, as described in claim 3, the seal portion is formed to have a diameter larger than that of the body portion, and a seal bead is provided at a portion in pressure contact with the dash panel. It shall be formed.

  Therefore, in at least the invention according to claim 1, if the neck portion center line is an assembly direction from the oblique direction of the grommet with respect to the dash panel, the neck portion is formed concentrically with the neck portion center line. Therefore, when the grommet is attached to the dash panel from an oblique direction, if the grommet seal part comes into contact with or sits on the dash panel, the grommet body part is easily deformable from the neck part to the neck part center line. It will compress or bend in the direction, that is, the assembly direction. Due to the compressive deformation or bending deformation of the body in the neck centerline direction (assembly direction), the whole seal part is pressed almost uniformly against the dash panel, and a part of the seal part is dragged and wound inside. It won't be lost.

  According to the present invention, since the neck portion of the middle portion in the longitudinal direction of the trunk portion of the grommet is formed concentrically with the neck portion center line inclined by a predetermined angle with respect to the axial center of the trunk portion, Without enlarging the size and weight, it is possible to prevent the seal portion from being caught when assembling to the dash panel, and to improve the sealing performance such as water tightness and sound insulation. In addition, if the center line of the neck part matches the assembling direction when assembling to the dash panel, the bending deformation of the grommet when the grommet contacts the dash panel becomes extremely stable, and the seal part This is further advantageous in preventing entrainment.

  In particular, according to the second aspect of the present invention, the inner and outer peripheral surfaces of the neck portion are constricted together, and the neck portion is formed to have a thinner shape than other portions. This is further advantageous in suppressing the increase in the weight.

BRIEF DESCRIPTION OF THE DRAWINGS Explanatory drawing which shows schematic structure of the steering apparatus for vehicles to which this invention is applied. Expansive sectional explanatory drawing around the grommet in FIG. Plane explanatory drawing by the grommet single shown in FIG. Front explanatory drawing by the grommet single shown in FIG. Cross-sectional explanatory drawing along the AA line of FIG. It is a figure which shows the assembly | attachment procedure of the structure shown in FIG. 2, and sectional explanatory drawing which shows the state before a grommet contact | abuts a dash panel. It is a figure which shows the assembly | attachment procedure of the structure shown in FIG. 2, and is sectional explanatory drawing which shows the state immediately after a grommet contact | abutted to the dash panel. Explanatory drawing at the time of the malfunction generation | occurrence | production in the part corresponded to the a part of FIG.

  1 to 7 show a more specific form for carrying out the sealing structure of the vehicle steering device according to the present invention, and in particular, FIG. 1 shows the schematic structure of the vehicle steering device, and FIG. Each drawing shows the detailed structure of the grommet.

  The steering device shown in FIG. 1 is roughly divided into a steering wheel 1, a rack and pinion type steering gear box 2, and a steering shaft 3 including first to third shaft elements 3a to 3b. Yes. Then, the third shaft element 3c is inserted through the hole 5 formed in the dash panel 4 that separates the engine room R1 and the vehicle compartment R2, and the dash panel 4 and the steering gear box 2 Between these, a cylindrical grommet 6 is mounted so as to cover the third shaft element 3c. In the present embodiment, the steering gear box 2 corresponds to a steering shaft-related component described later.

  The first to third shaft elements 3 a to 3 c are connected to each other through universal joints 7 and 8. The front end of the third steering shaft 3 c is connected to a pinion 9 in the steering gear box 2. The pinion 9 meshes with a rack shaft 10 provided so as to be able to reciprocate in the vehicle width direction, and both ends of the rack shaft 10 are connected to the knuckle arms of the left and right front wheels via tie rods to rotate the steering wheel 1. The left and right front wheels are steered according to the operation.

  As described above, the grommet 6 is formed into a stepped cylindrical shape with a rubber-based flexible material so that it can be externally inserted into the third shaft element 3c and cover the third shaft element 3c. FIG. 2 shows an enlarged sectional view around the grommet 6 in FIG. As shown in FIG. 2, the grommet 6 has a substantially shallow dish-like shape that functions as a seal portion having a larger diameter than the body portion 11 at one end of the body portion 11 having a shape in which an intermediate portion in the axial center direction is constricted. The flange portion 12 is integrally formed and the third shaft element 3c protrudes from the other end. The thick and irregular shape is seated and fitted to a part of the steering gear box 2 as a steering shaft-related component. A mounting base 13 is formed.

  And in the regular assembly | attachment state like FIG. 2, since the 3rd shaft element 3c which protrudes from the steering gear box 2 faces in the compartment R2 from the hole part 5 formed in the dash panel 4, engine The grommet 6 that covers the portion adjacent to the dash panel 4 on the room R1 side is bent or compressed in the axial direction between the steering gear box 2 and the dash panel 4, and the mounting base 13 is steered. The flange portion 12 is pressed around the hole portion 5 of the dash panel 4 while being seated and fitted to a part of the gear box 2. Thereby, the space between the hole 5 formed in the dash panel 4 and the steering gear box 2 is sealed, and airtightness, watertightness, and sound insulation are ensured. As a matter of course, the third shaft element 3 c does not contact the inner peripheral surface of the grommet 6.

  3 to 5 show details of the grommet 6 shown in FIG. 2 alone, FIGS. 3 and 4 are a plan view and a front view of the grommet 6 alone, and FIG. 5 is taken along line AA in FIG. Each cross-sectional view is shown.

  As shown in FIGS. 3 to 5 in addition to FIG. 2, the grommet 6 is a neck portion having a shape in which the inner and outer peripheral surfaces are constricted in such a manner that the diameter thereof is locally reduced to an intermediate portion in the axial center direction of the hollow cylindrical body portion 11. 14 is formed, thereby ensuring the ease of deformation in the axial direction of the body 11 itself. The neck portion 14 is formed to be relatively thin compared to other portions, and has a V-shaped cross section and gradually protrudes toward the inner peripheral side while gradually changing so as to reduce the thickness. If attention is paid to the change in the inner diameter, the portion corresponding to the neck portion 14 is a constricted portion 14a having the smallest inner diameter.

  Further, the outer peripheral surface of each of the portions on both sides in the axial center direction across the neck portion 14 of the body portion 11, that is, the portion closer to the flange portion 12 and the portion closer to the mounting base portion 13 across the neck portion 14. They are eccentric to each other, and the inner peripheral surfaces of both sides in the axial direction across the neck portion 14 are also eccentric to each other.

  A large number of fine seal beads 12a are formed in an annular shape on the front end surface of the flange portion 12 having a diameter larger than that of the body portion 11 and which is in contact with the dash panel 4, and are relatively thick. A stepped portion 13a for receiving the steering gear box 2 described above is formed on the inner periphery of the mounting base 13, and a plurality of seal beads 13b are formed in an annular shape on the inner peripheral surface. .

  In addition, when the axial center of the trunk portion 11 including the flange portion 12 and the mounting base portion 13 is C1, and the center line inclined by a predetermined angle with respect to the axial center C1 is the neck portion center line C2, the neck portion 14 Is formed concentrically with the neck portion center line C2 with respect to the neck portion center line C2. That is, when attention is paid to the narrowed portion 14a having the smallest inner diameter among the inner peripheral surfaces of the neck portion 14, the narrowed portion 14a is formed concentrically with the neck portion center line C2 in a plane orthogonal to the neck portion center line C2. Will be. This is the same at any position of the neck portion 14. Therefore, in the cross section of the grommet 6 shown in FIG. 5, the angles β1 and β2 formed by the inner peripheral surfaces of the neck portions 14 on both sides of the neck portion center line C2 are substantially equal to each other (β1 ≒ β2).

  Here, when the grommet 6 is previously attached to the third shaft element 3c on the engine room R1 side and the third shaft element 3c is assembled at a predetermined position, for example, interference with the vehicle body or other parts is avoided. For this reason, the assembly direction of the third shaft element 3c from the engine room R1 side is limited, and the flange portion 12 of the grommet 6 must be assembled to the dash panel 4 from an oblique direction rather than a direction perpendicular to the plane. I mentioned earlier that there may not be. This is not an exception in the present embodiment, and as shown in FIG. 6, the third shaft element 3 c on which the grommet 6 is extrapolated in advance is inclined with respect to the dash panel 4 in the direction of the arrow Q. Is assembled from

  For this reason, in the sealing structure with the grommet 6 according to the present embodiment, as shown in FIG. 6, the neck portion center line C2 is preliminarily aligned with the assembly direction Q, and the third structure including the steering gear box 2 is included. The shaft element 3c is assembled to the dash panel 4 side by pushing it up along the neck portion center line C2.

  In FIG. 6, when the third shaft element 3c is pushed up in the assembling direction Q along the neck portion center line C2 with respect to the dash panel 4, first, as shown in FIG. The front end surface comes into contact with the dash panel 4. If a pressing force is applied to the dash panel 4, the flange portion 12 already in contact with the dash panel 4 is bent and deformed from the broken line state to the solid line state in FIG. The neck portion 14 is bent and deformed so as to be compressed along the neck portion center line C2.

  In this case, the neck portion 14 is not only formed to be relatively thin and easily deformable, but the neck portion 14 is concentric with the neck portion center line C2 that coincides with the assembly direction Q in FIG. Further, as shown in FIG. 5, the angles β1 and β2 formed by the inner peripheral surfaces of the neck portions 14 on both sides of the neck portion center line C2 are substantially equal to each other. Yes. Therefore, even if the neck portion center line C2 is not perpendicular to the dash panel 4, as long as the flange portion 12 is seated on the dash panel 4, the trunk portion 11 starts from the neck portion 14 as the center of the neck portion. It will bend and deform smoothly and stably so as to be compressed in the direction of the line C2.

  2 and 7, the grommet 6 is held in a predetermined compressed state between the dash panel 4 and the steering gear box 2 in the regular assembled state shown in FIGS. A predetermined sealing function is exhibited by press-contacting to 4. 2 and 7, the pressure contact force of the flange portion 12 with respect to the dash panel 4 depends on the self-elastic force of the grommet 6 itself. The flange portion 12 is pressed from the direction perpendicular to the surface, and the uniform sealing function is exhibited on the entire circumference.

  In addition, when the trunk | drum 11 does not have the neck part 14, or when the deformation | transformation deformation | transformation in the said part is not enough even if the thing equivalent to the neck part 14 is formed, the flange part 12 is a dash panel. 4, as shown in FIG. 8 corresponding to part a of FIG. 7, a part of the front end surface of the flange portion 12 is dragged along with the bending deformation of the body portion 11 or the flange portion 12. The part may be caught inside. In such a case, a part of the front end surface of the flange portion 12 is lifted off from the dash panel 4 and causes a sealing failure and the intended purpose cannot be achieved. On the other hand, in the present embodiment described above, such a problem can be prevented without fail.

  As described above, according to the present embodiment, the neck portion 14 in the middle portion in the longitudinal direction of the trunk portion 11 of the grommet 6 is concentric with the neck portion center line C2 inclined at a predetermined angle with respect to the axis C1 of the trunk portion 11. Therefore, without causing an increase in the size and weight of the grommet 6 as in the prior art, it is possible to prevent the flange portion 12 from being caught when assembled to the dash panel 4, Sealing properties such as water tightness and sound insulation are improved.

  Moreover, the inner and outer peripheral surfaces of the neck portion 14 are constricted together, and the neck portion 14 is formed as a relatively thin-walled shape compared to other parts, so that the weight of the grommet 6 is increased. It can be further suppressed.

  In this embodiment, the steering gear box 2 is used as a steering shaft-related component, and the mounting base 13 of the grommet 2 is seated and fitted to a part of the steering gear box 2, but the mounting base 13 The seating / fitting part is not necessarily limited to a part of the steering gear box 2. For example, depending on the specifications of the steering device, the mounting base 13 may be seated / fitted to a part other than the steering gear box 2. Anyway.

2. Steering gear box (steering shaft related parts)
3a ... 3rd shaft element 4 ... Dash panel 5 ... Hole 6 ... Grommet 11 ... Body 12 ... Flange (seal)
DESCRIPTION OF SYMBOLS 13 ... Mounting base 14 ... Neck part C1 ... Axis center of trunk | drum C2 ... Neck part centerline Q ... Assembling direction R1 ... Engine room R2 ... Car compartment

Claims (3)

The steering shaft that is arranged so as to penetrate the dash panel that separates the passenger compartment from the engine room is covered with a grommet on the engine room side and close to the dash panel, and the grommet is pressed against the dash panel for sealing. In the vehicle steering device seal structure,
In the grommet, a seal portion that presses against the dash panel is formed at one end of a cylindrical body portion that is externally attached to the steering shaft, and a mounting base portion that is fixed to a steering shaft related component is formed at the other end of the cylindrical body portion. And
A neck portion having a constricted shape that is easily deformable is formed in an intermediate portion in the axial direction of the trunk portion,
The neck structure is formed concentrically with the center line of the neck part with respect to the center line of the neck part inclined at a predetermined angle with respect to the axial center of the body part.   2. The vehicle steering apparatus according to claim 1, wherein the neck portion has a shape in which the inner and outer peripheral surfaces thereof are constricted together, and is formed to have a thinner shape than other portions. Seal structure.   3. The vehicle steering apparatus according to claim 2, wherein the seal portion is formed to have a diameter larger than that of the body portion, and a seal bead is formed at a portion in pressure contact with the dash panel. Seal structure.

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