JP2016055831A - Grommet for vehicular steering device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a grommet for a vehicular steering device capable of assuring fitting of a fitting base and improving sealing performance of a sealing part to achieve watertightness, acoustic insulation or the like during assembling while reducing the weight of the grommet.SOLUTION: A portion of a third shaft element 3a penetrating a dashpanel 4, which approaches the dashpanel 4 on an engine room R1 side is covered with a grommet 6, and the grommet 6 is pressed into contact with the dashpanel. The grommet includes a cylindrical fitting base made of a hard thermoplastic resin and fixed to the cylindrical part 2b of a steering gear box 2 via male screw parts 2c and 12a, a cylindrical part 13 provided integrally with the fitting base and fitted around a steering shaft, and a sealing part 20 provided at the upper end of the cylindrical part to be pressed into contact with the dashpanel, and the sealing part is made of rubber or thermoplastic elastomer softer than the thermoplastic resin.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a grommet for a vehicle steering system that covers a portion of a steering shaft that is disposed so as to penetrate a dash panel that separates a vehicle compartment from an engine room, and that is close to the dash panel on the engine room side. Is.

  As this type of grommet for a conventional vehicle steering device, for example, a grommet described in Patent Document 1 below is provided.

  The grommet is integrally formed of a rubber-based flexible material, is formed in a substantially drum shape along the axial direction of the steering shaft, and is a large-diameter cylindrical shape that is attached to the steering gear box in a fitted state. Mounting base, an end portion of the mounting base, a flexible cylindrical portion, and a distal end side of the cylindrical portion, the inner peripheral contact portion being a seal surface of the dash panel A large-diameter cylindrical seal portion that comes into contact with the main body.

  The seal portion has an outer stopper portion that protrudes outward on the outer peripheral side and does not contact the dash panel when assembled, and a part of the inner peripheral contact portion of the seal portion is assembled during assembly. When the outer stopper portion comes into contact with the dash panel when it is pulled in the direction and is about to be caught inside due to a twisting phenomenon, the seal portion is prevented from being caught.

JP 2011-79473 A

  However, the conventional grommet described in Patent Document 1 is integrally formed of a rubber-based flexible material, so that the steering gear box and the dash panel are inserted while being externally attached to the steering shaft. When assembled in the middle, unnecessary bending deformation may occur, and the mounting base portion may be misaligned with respect to the steering gear box, and irregular sealing of the seal portion may cause a sealing failure with respect to the sealing surface of the dash panel. .

  Therefore, in order to ensure the rigidity of the grommet and suppress unnecessary bending deformation, it has been considered to increase the overall thickness, but in this case, the overall size and weight of the grommet are increased. It is not preferable.

  The present invention has been devised by paying attention to the above-mentioned conventional technical problems, and is capable of reducing the size and weight of the grommet while suppressing the displacement of the mounting base during assembly, and ensuring the mounting. It is an object of the present invention to provide a grommet for a vehicle steering apparatus that can improve sealing performance such as water tightness and sound insulation.

  According to the first aspect of the present invention, the grommet covers a portion of the steering shaft that is disposed so as to penetrate the dash panel that separates the vehicle compartment and the engine room from the grommet on the engine room side and is close to the dash panel. In the grommet for a vehicle steering device that is sealed by being pressed against the dash panel, the grommet is provided integrally with a cylindrical mounting base that is fixed to a related part of the steering shaft, and the mounting base. A cylindrical portion that is externally attached to the steering shaft, and a seal portion that is provided at one end of the cylindrical portion and press-contacts the dash panel, and at least the mounting base is formed of a thermoplastic resin. And an internal thread that is screwed onto an external thread formed on the inner peripheral surface of the related part. While are formed over a substrate wherein the sealing portion is characterized in that than the thermoplastic resin is formed by rubber or thermoplastic elastomer soft.

  Therefore, in the present invention, when the grommet is attached to the related part of the steering shaft, the hard mounting base is fixed to the related part by screwing through the female and male screw parts, so that the bending deformation of the mounting base as in the prior art is prevented. Not only does it disappear, but there is no effect on the seal due to external forces. Therefore, unnecessary deformation of the mounting base and the seal portion is sufficiently suppressed, stable holding performance of the mounting base is obtained, and uniform pressure contact of the seal portion with the dash panel is obtained, so that the sealing performance can be improved. .

  According to a second aspect of the present invention, a seal member that seals between the related parts is provided inside the attachment base portion, and the seal member is a sponge rubber softer than the thermoplastic resin or It is characterized by being formed of a thermoplastic elastomer.

  The invention according to claim 3 is characterized in that a positioning projection is provided on the outer periphery of the mounting base portion so as to contact a positioning stopper provided in the related part from the circumferential direction.

  According to the first aspect of the present invention, since the attachment base of the grommet is formed of a highly rigid thermoplastic resin, the seal portion is formed of a soft material such as a rubber material, so that the grommet can be reduced in size and weight. In addition, it is possible to suppress the positional deviation of the mounting base at the time of assembly and improve the sealing performance such as the reliable mounting and the water-tightness and sound insulation by the sealing portion.

  According to the second aspect of the present invention, the seal bead provided between the attachment base and the related part can improve the sealing performance between the two, and can suppress the backlash of the grommet and the generation of abnormal noise.

  According to the third aspect of the present invention, when the grommet is attached, the grommet is securely placed in a proper position by screwing the attachment base until the positioning projection of the attachment base comes into contact with the positioning stopper of the related part. Can be attached.

It is the schematic which shows embodiment of the steering device for vehicles to which this invention is applied. It is an expanded sectional view around the grommet in FIG. It is the sectional view on the AA line of FIG. It is a perspective view of the grommet provided for this embodiment. It is an expanded sectional view around the grommet which shows the assembly | attachment state of the grommet in this embodiment.

  1 to 5 show a more specific form for carrying out a grommet for a vehicle steering apparatus according to the present invention, and in particular, FIG. 1 shows a schematic structure of the vehicle steering apparatus, and FIG. Each structure is shown.

  The steering apparatus shown in FIG. 1 includes 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.

  The third shaft element 3c is inserted through a hole 5 formed in the dash panel 4 that separates the engine room R1 and the vehicle compartment R2 from each other. Between the gear box 2, a cylindrical grommet 6 is mounted so as to cover the third shaft element 3c.

  The steering gear box 2 corresponds to a steering shaft related part to be described later, and includes a box main body 2a and a cylindrical portion 2b integrally provided at an end of the box main body 2a on the dash panel 4 side. I have. As shown in FIG. 2, the cylindrical portion 2b has a male screw portion 2c with a relatively large pitch interval formed on the entire outer peripheral surface, and a positioning stopper serving as a positioning stopper on the outer peripheral surface of the connecting portion with the box body 2a. The convex part 7 is provided integrally.

  The positioning convex portion 7 is integrally formed on the upper surface of the box body 2a, is formed in an arc shape along the outer peripheral surface of the cylindrical portion 2b, and the arc length is approximately 1/4 of the circumferential direction. Is set to the length of Further, one end 7a in the longitudinal direction (circumferential direction) of the positioning convex portion 7 is such that a positioning projection 21 (to be described later) of the grommet 6 is circumferential when the grommet 6 is screwed into the male screw portion 2c to the maximum. It is abutted to prevent further screwing rotation.

  The first to third shaft elements 3 a to 3 c are connected to each other through universal joints 8 and 9. The front end of the third steering shaft 3 c is connected to the pinion 10 in the steering gear box 2. The pinion 10 meshes with a rack shaft 11 provided so as to be capable of reciprocating in the vehicle width direction, and both ends of the rack shaft 11 are connected to the knuckle arms of the left and right front wheels via tie rods. The left and right front wheels are steered according to the rotation operation.

  As shown in FIGS. 2, 4, and 5, the grommet 6 is extrapolated to the third shaft element 3c and formed in a substantially trumpet shape as a whole, and is provided at one end in the longitudinal direction. A cylindrical mounting base 12 that is fixedly attached to the cylindrical portion 2 b of the steering gear box 2, a cylindrical portion 13 that is integrally provided on the upper end side of the mounting base 12, and an upper end side of the cylindrical portion 13 And a large-diameter annular seal portion 14 provided integrally.

  The mounting base portion 12 and the cylindrical portion 13 are formed integrally with a hard thermoplastic resin and are relatively thin with a thickness of about 3 to 4 mm. The mounting base portion 12 is formed in a cylindrical shape having a uniform outer diameter, and a female screw portion 12a that can be screwed to a male screw portion 2c formed on the outer periphery of the cylindrical portion 2b of the steering gear box 2 on the inner peripheral surface. Is formed.

  The cylindrical portion 13 includes a small-diameter cylindrical portion 15 that is integrally coupled to the upper end of the mounting base portion 12 from the axial direction, and a large-diameter cylindrical portion 16 that is integrally provided at the upper end portion of the small-diameter cylindrical portion 15. ing. The small diameter cylindrical portion 15 has an axial center X arranged coaxially with the mounting base 12 and an outer diameter smaller than the mounting base 12, and a lower end and an upper end 12 b of the mounting base 12. An annular step surface 17aa is formed on the inner surface of the step portion 17 therebetween.

  The large-diameter cylindrical portion 16 is integrally connected to the small-diameter cylindrical portion 15 so as to be continuously connected to the small-diameter cylindrical portion 15 so as to expand upward (in a trumpet shape). It is comprised from the large diameter annular part 16b. The diameter-enlarged portion 16a is formed in an inclined shape with an angle of about 30 ° with respect to the axis X of the small-diameter cylindrical portion 15. Therefore, the annular portion 16b is inclined at an angle of about 30 °. . As shown in FIGS. 1 and 5, the inclination angle is set so that the contact portion 20 described later of the seal portion 14 of the grommet 6 is equal to the angle of the inclined contact surface 4 b of the attachment portion 4 a of the dash panel 4. The angle is adjusted to the close contact state.

  In addition, a seal ring 18, which is an annular seal member, is disposed on the step surface 17 a of the step portion 17 formed between the mounting base portion 12 and the small diameter cylindrical portion 15. The seal ring 18 is formed in an annular shape by sponge rubber or thermoplastic elastomer softer than the thermoplastic resin forming the mounting base 12 and the cylindrical portion 13, and the mounting base 12 is a cylinder of the steering gear box 2. When screwed into the part 2b via the male and female threaded parts 2c and 12b, it is compressed and deformed by the clamping force between the stepped surface 17a and the upper end surface of the cylindrical part 2b, and a sealing function is provided between the two parts 2b and 17a. Has come to demonstrate. The seal ring 18 may be formed integrally with the step surface 17a.

  The seal portion 14 is integrally coupled to the upper edge of the peripheral wall of the annular portion 16b of the large-diameter cylindrical portion 16, and is integrally formed by rubber or thermoplastic elastomer softer than the thermoplastic resin of the large-diameter cylindrical portion 16. An elastic base 19 integrally formed with the annular portion 16b of the large-diameter cylindrical portion 16 and an abutting portion 20 provided integrally with the upper end of the elastic base 19 and abutting against the dash panel 4 And is composed of.

  The seal portion 14 may be formed separately and fixed to the upper edge of the peripheral wall of the annular portion 16b with an adhesive.

  The elastic base portion 19 is thin and has a substantially arcuate cross section so that it can be flexed and deformed relatively freely. On the other hand, the contact portion 20 is formed in a relatively thick annular shape, and a large number of fine seal beads 20a in contact with the contact surface 4b of the dash panel 4 on the outer peripheral side of the upper surface. Is formed.

  Further, the mounting base 12 has a positioning projection 21 that abuts the positioning convex portion 7 of the steering gear box 2 on the outer peripheral surface of the lower end portion from the circumferential direction and regulates the circumferential position of the entire grommet 6. It is provided integrally.

As shown in FIG. 4, the positioning projection 21 is formed in a substantially rectangular block shape, and the formation position of the positioning projection 21 is set to the cylindrical portion 2 b of the steering gear box 2 via the male and female screw portions 2 c and 12 a. The entire upper surface (seal bead 20a) of the contact portion 20 of the seal portion 14 is brought into contact with the contact surface 4b of the dash panel 4 in a state where the seal ring 18 of the stepped surface 17a is finally slightly pressed into contact with each other. It is set to come to the position where it abuts. That is, the entire upper end inclined surface of the contact portion 20 of the seal portion 14 is in a position where it is elastically contacted with the contact surface 4b of the dash panel 4 with substantially uniform pressure in a position-controlled state.
[Operation and effect of this embodiment]
Therefore, according to this embodiment, the grommet 6 is extrapolated in advance to the third shaft element 3c of the steering shaft 3 on the engine room R1 side, and then the third shaft element 3c is attached to the gear box 2. After that, the grommet 6 is attached and fixed to the cylindrical portion 2b of the steering gear box 2 via the attachment base 12.

  That is, the lower end portion of the mounting base portion 12 of the grommet 6 is fitted to the tip portion of the cylindrical portion 2b and is screwed in via the female and male screw portions 2c and 12a.

  Thereafter, as shown in FIGS. 2 to 4, the mounting base 12 is further screwed, and the positioning projection 21 is brought into contact with the positioning projection 7 of the cylindrical portion 2 b from the circumferential direction, and further screwing rotation is restricted. Then, the grommet 6 is held at a normal position.

  And in the regular assembly | attachment state shown in FIG. 5, since the contact part 20 contact | abuts the contact surface 4b of the dash panel 4 and the force is applied to the seal part 14 of the grommet 6 in the compression direction, The contact portion 20 moves in the direction of the large-diameter cylindrical portion 16 (annular portion 16b) by flexibly bending and deforming in the direction of the large-diameter cylindrical portion 16.

  At this time, the elastic base portion 19 is in a state where the upper end inclined surface (seal bead 20a) of the contact portion 20 is pressed in the direction of the contact surface 4b by the elastic force in a state of being bent and deformed.

  As described above, according to this embodiment, the rigid mounting base portion 12 made of a thermoplastic resin material is fixed to the cylindrical portion 2b of the steering gear box 2 by screwing via the male and female screw portions 2c and 12a. The bending deformation of the mounting base 12 as in the technique is completely eliminated, and the influence on the seal portion 14 due to external force is also eliminated. Therefore, useless deformation of the mounting base 12 and the seal portion 14 is sufficiently suppressed, and the mounting base 12 can be stably and firmly attached to the cylindrical portion 2b without being detached from the cylindrical portion 2b. As a result, the holding force of the mounting base 12 with respect to the steering gear box 2 can be improved.

  Further, since the seal portion 14 is not affected by an external force, the entire seal bead 20a of the contact portion 20 can be brought into pressure contact with the contact surface 4b of the dash panel 4 with a uniform force. As a result, the sealing performance such as water tightness and sound insulation by the seal portion 14 can be improved.

  Moreover, since the elastic reaction force is generated in the seal ring 18 by screwing the mounting base portion 12, the elastic reaction force can suppress the play between the mounting base portion 12 and the cylindrical portion 2b. Occurrence can be prevented. Moreover, the sealing performance between the two 12 and 2b is improved by the elastic reaction force of the seal ring 18.

  Furthermore, the attachment base 12 and the cylindrical portion 13 are continuously formed integrally with a hard thermoplastic resin, and the thickness can be reduced to about 3 to 4 mm. For this reason, sufficient rigidity can be achieved and significant weight reduction can be achieved without increasing the thickness of the entire mounting base 12 or the cylindrical portion 13 or providing a reinforcing rib or the like to increase the rigidity.

  Further, the positioning projection 21 provided on the box body 2a of the steering gear box 2 can be brought into contact with the positioning projection 21 of the mounting base 12 so that the entire grommet 6 can be mounted at a proper position. Insufficient screwing of the base 12 can be prevented. As a result, the grommet 6 can be stably and reliably held at the normal position.

  In this embodiment, the steering gear box 2 is used as a steering shaft-related component, and the mounting base 12 of the grommet 6 is fixed to the cylindrical portion 2b of the steering gear box 2, but the seating / fitting portion of the mounting base 12 Is not necessarily limited to the cylindrical portion 2b of the steering gear box 2. For example, depending on the specifications of the steering device, the mounting base 12 may be fixed to a portion other than the steering gear box 2.

  In the present embodiment, the enlarged diameter portion 16a and the annular portion 16b of the grommet 6 are formed to be inclined with respect to the axis X of the small diameter cylindrical portion 15, but are not necessarily formed to be inclined. For example, the enlarged diameter portion 16 a and the annular portion 16 b may be formed concentrically with the axis X of the small diameter cylindrical portion 15.

2. Steering gear box (steering shaft related parts)
2a ... Box body 2b ... Cylindrical part 2c ... Male thread part 3 ... Steering shaft 3c ... Third shaft element 4 ... Dash panel 4a ... Mounting part 4b ... Abutting surface 6 ... Grommet 7 ... Positioning convex part 7a ... One end surface 12 ... Mounting base 12a ... Female thread portion 13 ... Cylindrical portion 14 ... Sealing portion 15 ... Small diameter cylindrical portion 16 ... Large diameter cylindrical portion 17 ... Stepped portion 17a ... Stepped surface 18 ... Seal ring (seal member)
DESCRIPTION OF SYMBOLS 19 ... Elastic base 20 ... Contact part 20a ... Seal bead 21 ... Protrusion for positioning R1 ... Engine room R2 ... Car compartment

Claims (3)

Of the steering shaft that is arranged to penetrate the dash panel that separates the passenger compartment from the engine room, the part close to the dash panel on the engine room side is covered with grommet, and this grommet is pressed against the dash panel. In the grommet for a vehicle steering device designed to be sealed,
The grommet includes a cylindrical mounting base that is fixed to a related part of the steering shaft, a cylindrical portion that is provided integrally with the mounting base, and is externally inserted into the steering shaft, and one end of the cylindrical portion. A seal portion that is in pressure contact with the dash panel,
While at least the mounting base is formed of a thermoplastic resin, an internal thread portion is formed on the inner peripheral surface of the external thread portion to be screwed to the external thread portion formed on the related part.
The grommet for a vehicle steering apparatus, wherein the seal portion is made of a softer rubber or thermoplastic elastomer than the thermoplastic resin.   A seal member that seals between the related parts is provided inside the mounting base, and the seal member is made of sponge rubber or thermoplastic elastomer that is softer than the thermoplastic resin. The grommet for a vehicle steering device according to claim 1.   The grommet for a vehicle steering apparatus according to claim 2, wherein a positioning projection is provided on the outer periphery of the mounting base so as to contact a positioning stopper provided in the related part from the circumferential direction.

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