JP4087386B2 - Wheel nut and manufacturing method thereof - Google Patents

Description

  The present invention relates to a wheel nut (also referred to as a hub nut) used for fastening a hub on a vehicle body side and a disc wheel, and a manufacturing method thereof.

  Conventionally, in this kind of wheel nut, in order to improve aesthetics, a cap is put on and used. As a method for attaching the cap, for example, as shown in Patent Document 1, there is a proposal in which the cap edge is bent around the flange (caulked) to eliminate the need for attachment by welding.

JP-A-11-51031

  However, in Patent Document 1, a structure that requires caulking and that does not act so as to move the cap by separating the cap edge from the load receiving surface of the flange is essential, and the shape of the flange is restricted.

  The present invention has been made on the basis of the above-mentioned background. A wheel nut with improved liquid-tightness and manufacturing thereof, which does not require a chamfering process when mounting the cap, does not require mounting by welding, can have a somewhat free flange shape, and its manufacture. It is an object to provide a method.

Means for Solving the Problems and Effects of the Invention

This wheel nut is a wheel nut for fastening the disc wheel to the hub on the vehicle body side,
It is possible to apply torque with a tool such as a wrench connected to the flange portion, a female screw portion that is screwed with a male screw portion of a wheel bolt provided on the hub side, a flange portion that receives a fastening force due to screwing with the wheel bolt, and the like. A nut body having a possible tool engagement portion;
A cap main body that closes the opening on the side opposite to the screw engagement start side with the wheel bolt of the female screw portion, a cylindrical portion that is connected to the cap main body and covers the tool engaging portion, and a continuous connection to the cylindrical portion A cap having a skirt portion disposed in close contact with the inclined portion of the flange portion extending away from the tool engaging portion in the radially outward direction,
The inner surface dimension of the cylinder part when viewed from the axial direction of the cap is formed to be smaller than the outer surface dimension of the tool engagement part when viewed from the axial direction of the nut body, and the cylindrical part of the cap is tightened to the outer peripheral surface of the tool engagement part of the nut body. while being pressed by Me fly skirt is pressed from its front end portion to the inclined portion of the flange portion, it is assumed that they are in close contact with the inclined portion of the flange portion by an elastic force of the skirt portion.

In the wheel nut, the cylindrical portion of the cap is press-fitted into the outer peripheral surface of the tool engaging portion of the nut body with an interference fit, and is moved radially outward from the tool engaging portion (for example, a hexagonal portion) in the nut body. The skirt part is pressed from the tip of the inclined part of the flange part that extends in this way, and is closely attached to the inclined part of the flange part by the elastic force of the skirt part. No need to install by welding, and it is possible to easily attach the cap. As for the shape of the flange portion, the inclined portion is formed only at the portion connected to the tool engaging portion, and the shape can be made somewhat free without any other structural restrictions.

In order to solve the above problems, the wheel nut of the present invention is a wheel nut for fastening a disc wheel to a hub on the vehicle body side,
A female screw portion that is screwed with a male screw portion of a wheel bolt provided on the hub side, and a pressure receiving surface that receives a fastening force by screwing with the wheel bolt, and a height from the pressure receiving surface on the opposite side to the pressure receiving surface There have a inner circumferential side inclined surface is the outer circumferential side becomes lower than the flange portion stepped portion is circumferentially formed on its outer peripheral edge, the tool engagement portion provided continuously on the inclined surface side of the flange portion A nut body having
A cap main body portion that closes the opening on the side opposite to the screwing start side of the female screw portion with the wheel bolt, and a cross-sectional shape similar to the cross-sectional shape of the tool engaging portion of the nut main body that is connected to the cap main body portion. A cylindrical portion that is press-fitted into the tool engaging portion with an interference fit and covers a side surface portion of the tool engaging portion, and radially outward from the cylindrical portion so as to face the inclined surface of the flange portion. And a cap having a skirt portion formed in a slope shape so as to be away from,
An inclination angle formed by a direction perpendicular to the axis of the cylinder portion of the cap and the skirt portion is formed larger than an inclination angle formed by a direction perpendicular to the axis of the nut body and the inclined surface of the flange portion, and the cap When the cylindrical portion is pressed into the outer peripheral surface of the tool engaging portion of the nut body with an interference fit, the skirt portion is pressed against the inclined surface of the flange portion and elastically deformed, and at least the outer peripheral portion of the skirt portion is It is closely attached to the inclined surface of the flange portion by an elastic force due to the elastic deformation, and the tip end portion of the skirt portion is in contact with the stepped portion in a form along the stepped portion. To do.

In the wheel nut of the present invention, the skirt portion of the cap is formed in a slope shape so as to move radially outward from the tube portion, and the inclination angle formed between the direction perpendicular to the axis of the tube portion of the cap and the skirt portion is The inclination angle formed between the direction perpendicular to the axis of the nut body and the inclined surface of the flange portion is larger. For example, the inclination angle formed between the direction perpendicular to the axis of the cylinder portion and the skirt portion of the cap and the skirt portion may be set larger by 0.5 to 10 degrees than the angle formed between the direction perpendicular to the axis of the nut body and the inclined surface. it can. By forming the skirt portion in this way, when the cylinder portion of the cap is press-fitted into the outer peripheral surface of the tool engaging portion of the nut body with an interference fit, the skirt portion is pressed against the inclined surface of the flange portion to be elastic. Deformation, at least the outer periphery of the skirt portion is in close contact with the inclined surface of the flange portion by the elastic force due to the elastic deformation, exhibiting a tight contact state without gaps, maintaining the liquid tightness between the cap and the nut body, The function to prevent the intrusion of water inside can be enhanced. As described above, the cap is attached to the inclined surface of the flange portion of the nut body by the elastic force due to the deformation of the skirt portion, so that the caulking process is unnecessary and the attachment by welding is unnecessary and the cap can be easily attached. As for the shape of the flange portion, the inclined portion is formed only at the portion connected to the tool engaging portion, and the shape can be made somewhat free without any other structural restrictions. Furthermore, since the stepped portion is formed in a circumferential shape on the outer peripheral edge of the inclined surface of the nut body, the tip of the skirt portion of the cap engages and closely contacts the stepped portion in a form along the stepped portion. To do. Thereby, the adhesiveness to the inclined surface of the flange part in the front-end | tip part of a skirt part can be improved, the penetration | invasion to the inside of water can be prevented more, and it can become difficult to rust.

  At this time, the tool engaging portion of the nut body is formed in a hexagonal cross-sectional shape, while the cylinder portion of the cap is also formed in a hexagonal cross-sectional shape, and the corner radius of the cap is the same as or larger than the corner radius of the nut body. When the cylinder part of the cap is press-fitted into the outer peripheral surface of the tool engagement part of the nut body with an interference fit, the corner part of the cylinder part on the cap side extends and the corner part of the tool engagement part on the nut body side It can be in close contact with. Thereby, the adhesiveness of the cylinder part of a cap and the hexagonal-shaped part of a nut main body can be improved, and the liquid-tightness between a cap and a nut main body can further be improved.

  At that time, the tip of the skirt portion of the cap can be positioned closer to the inner peripheral side than the outer peripheral edge of the flange on the inclined surface side of the nut body. By forming the skirt portion in this way, the end portion of the skirt portion does not protrude and closely adheres along the flange portion (the inclined surface of the flange portion), and does not get caught, so the cap does not come off, And it can be in a stable and stable state.

By the way, it can express as follows about the manufacturing method of the wheel nut of this invention. And the internal thread portion to be screwed with the male screw portion of the wheel bolt provided on the hub side for securing the disc wheel, have a pressure receiving surface for receiving the fastening force by screwing between its wheel bolt, on the opposite side to the pressure receiving surface A flange portion having an inclined surface whose height from the pressure receiving surface is lower on the outer peripheral side than the inner peripheral side, and having a stepped portion formed circumferentially on the outer peripheral portion of the inclined surface, and the inclined surface of the flange portion Forming a nut body provided with a tool engaging portion continuously provided on the side;
A cap main body that closes the opening on the side opposite to the screwing start side of the female screw portion with the wheel bolt, and a cross-sectional shape similar to the cross-sectional shape of the tool engaging portion of the nut main body that is connected to the cap main body A cylindrical portion that covers the side surface portion of the tool engaging portion, and a skirt portion that is formed in a slope shape so as to be radially outward from the cylindrical portion so as to face the inclined surface of the flange portion. An inclination angle formed between a direction perpendicular to the axis of the cylinder part and the skirt part is larger than an inclination angle formed between a direction perpendicular to the axis of the nut body and the inclined surface of the flange part, Forming a cap;
The cylindrical portion of the cap is an interference fit with the outer peripheral surface of the tool engaging portion of the nut body, and at least the outer peripheral portion of the skirt portion is in close contact with the inclined surface of the flange portion, and the tip of the skirt portion of the cap A press-fitting step of press-fitting the cap into the nut main body so that the portion is in a form along the stepped portion and is in close contact with the stepped portion ;
It is characterized by including.

  At that time, in the press-fitting process, the outer peripheral edge of the skirt portion of the cap is pressed against the inclined surface of the flange portion and pressurized, and a crimp margin at the time of pressurization is formed on the outer peripheral edge of the skirt portion. The step of press-fitting the cap into the nut body can be included. By press-fitting the cap in this way, the adhesion to the inclined surface of the flange portion at the outer peripheral portion of the skirt portion becomes better.

In this case, the step of forming the nut body includes a step of forming a stepped portion circumferentially on the outer peripheral portion of the inclined surface, and in the press-fitting step, the tip of the skirt portion of the cap is in a form along the stepped portion. Since the cap includes a step of press-fitting the cap into the nut main body so as to engage and closely contact the stepped portion, it is possible to improve the adhesion to the flange portion at the tip of the skirt portion. Intrusion into the inside can be further prevented.

(Example)
Hereinafter, embodiments of the present invention will be described with reference to examples shown in the drawings. FIG. 1 is a front half sectional view and a plan view of a wheel nut 1 of the present invention. A wheel nut 1 shown in FIG. 1 is used to fasten a hub 2 and a disc wheel 3 on the side of a vehicle body such as an automobile arranged opposite to each other. A predetermined number of bolt insertion holes 3 a are formed in the disc wheel 3. Further, the hub 2 is formed with a through hole 2a having the bolt insertion hole 3a and the axis O in common. The wheel bolt 4 is fixed to the hub 2 so that the shaft portion 4a cannot be rotated by a method such as press fitting into the through hole 2a. The wheel nut 1 includes a nut body 10, a cap 20, and a washer 30.

  FIG. 2 is a front half sectional view and a plan view of the nut body 10. As shown in FIG. 2, the nut body 10 is screwed with a male screw portion 4 b (see FIG. 1) formed on the distal end side of the shaft-like portion 4 a of the wheel bolt 4 inserted from the hub 2 side into the bolt insertion hole 3 a. A female threaded portion 11 that engages with the wheel bolt 4, a flange portion 12 that receives a fastening force caused by screwing with the wheel bolt 4, a cylindrical portion 14 that projects from the flange portion 12 to the screwing start side 13, and the opposite side across the flange portion 12 And a hexagonal portion 15 (tool engaging portion) having a hexagonal cross-sectional shape.

  The hexagonal portion 15 can be engaged with a tool such as a wrench to apply torque to the wheel nut 1. Knurled eyes 16 are formed on the outer peripheral surface of the cylindrical portion 14 by knurling so that the washer 30 can be held. An opening 17 is formed on the opposite side of the nut body 10 from the screwing start side 13.

  The seat surface 12a (pressure receiving surface) of the flange portion 12 is formed in a direction perpendicular to the direction of the axis O of the bolt insertion hole 3a, and comes into contact with the end surface 30a of the washer 30 at the time of fastening. From the hexagonal portion 15 to the flange portion 12, an inclined portion 12b (inclined surface) is formed extending from the hexagonal portion 15 so as to move outward in the radial direction. That is, the inclined portion 12b is formed on the side opposite to the seating surface 12a of the flange portion 12 so that the height from the seating surface 12a is lower on the outer peripheral side than on the inner peripheral side.

  FIG. 3 is a front half sectional view and a plan view of the cap 20 and shows a state before the nut body 10 is assembled. As shown in FIG. 3, the cap 20 has a cylindrical shape whose upper part is closed as a whole, and a cap body 21 that closes the opening 17 of the nut body 10, and a hexagonal portion that is connected to the cap body 21. 15, a cylindrical portion 22 having a hexagonal cross-sectional shape similar to the cross-sectional shape of the hexagonal portion 15, and the cylindrical portion 22 connected to the cylindrical portion 22 so as to move outward from the cylindrical portion 22 in the radial direction. And a skirt portion 23 formed in a slope shape. The skirt portion 23 is disposed opposite to the inclined portion 12 b of the flange portion 12. The skirt portion 23 has a radial dimension such that the lower end (tip) thereof is positioned closer to the front (inner peripheral side) than the outer peripheral edge between the lower end of the hexagonal portion 15 of the nut body 10 and the outer peripheral edge of the flange portion 12. Is stipulated. That is, when the cap 20 is assembled, the lower end of the peripheral edge of the skirt 23 is positioned on the inner peripheral side of the outer peripheral edge of the flange 12 (see FIG. 1).

  The washer 30 is formed in a trapezoidal shape in a half section including the axis O (see FIG. 1) of the bolt insertion hole 3a, is located between the disc wheel 3 and the nut body 10, and is formed with a cylindrical portion 14 ( A cylindrical portion 14) having knurled eyes 16 is fitted and attached. That is, the washer 30 includes an end surface 30a that contacts the seating surface 12a of the flange portion 12 of the nut body 10 at the time of fastening, a tapered outer peripheral surface 30b that contacts a tapered enlarged surface of the bolt insertion hole 3a, and an inner peripheral edge. A tapered washer having an end face 30a and a counterbore 30c opened on the opposite side is formed in the part. The washer 30 is pushed over the knurled eye 16 of the nut body 10 by press-fitting, and after the press-fitting, the washer 30 is held by the knurled eye 16 so as not to fall off and is held rotatably when not fastened. The knurled eyes 16 are hidden by the counterbore 30c.

  4A is an enlarged view of a portion A in FIG. 3 (an enlarged view of the skirt portion 23 of the cap 20), and FIG. 4B is an enlarged view of a portion B in FIG. 2 (an enlarged view of the inclined portion 12b of the nut body 10). It is. In the inclined portion 12b of the flange portion 12 of the nut body 10, the inclination angle formed between the inclined portion 12b and the perpendicular direction to the axis O of the hexagonal portion 15 of the nut body 10 having the same axis as the axis O of the bolt insertion hole 3a is defined as θ2. In the skirt portion 23 of the cap 20, when the angle of inclination between the skirt portion 23 and the direction perpendicular to the axis O of the cylindrical portion 22 of the cap 20 having the same axis as the axis O of the bolt insertion hole 3a is θ1, The configuration is such that θ1> θ2. That is, the inclination angle of the skirt portion 23 of the cap 20 is larger than the inclination angle of the inclined portion 12 b of the nut body 10. The lower end surface 23a of the skirt portion 23 has a shape substantially parallel to the axis O of the cylindrical portion 22 of the cap 20, and is an end surface inclined by a certain amount from the plate thickness direction of the skirt portion 23. This is because if it is a right angle, it can be creased, so this is solved to make it an obtuse angle, so after pressing (drawing) into a shape with a skirt part 23, the plate material (blank) is punched out and such An end face is formed.

  In the present embodiment, the cap 20 can be made of a material having a high Young's modulus, for example, a stainless steel plate (for example, austenite) having a thickness of 0.4 to 0.8 mm, particularly 0.5 to 0.6 mm. It is preferable to do this. The difference in inclination angle (θ1−θ2) can be set to 0.5 to 10 degrees, and is preferably set to 1 to 6.5 degrees.

  The dimension of the hexagonal part 15 of the nut body 10 and the dimension of the cylindrical part 22 of the cap 20 will be described. As shown in FIGS. 2 and 3, in the state before assembly, the two-surface width (outer surface dimension) of the hexagonal portion 15 is L2 when viewed from the axial direction, and the two-surface width (inner surface size) of the cylindrical portion 22 when viewed from the axial direction When L1 is L1, the configuration is such that L1 <L2. That is, the two-surface width (inner surface dimension) of the cylindrical portion 22 of the cap 20 is made smaller than the two-surface width (outer surface dimension) of the hexagonal portion 15 of the nut body 10. In the present embodiment, the interference fit ratio in the cylindrical portion 22 of the cap 20 can be set to 0.2 to 5%, and is preferably set to 0.25 to 1%.

Next, a method for manufacturing the wheel nut 1 will be described.
(1) The cap 20 is manufactured by a method called a progressive mold shown in FIG. As shown in FIG. 5, after passing through the “guide pushing” step, the “double pushing” step, and the “partial cutting (slit formation)” step, one flat plate is formed into a container with a bottom using a guide. Molded step by step and partially cut in an intermediate step. Subsequently, through a plurality of “drawing” steps, redrawing is performed step by step, the depth is increased to form a predetermined shape, and the final “separation” step is cut into predetermined dimensions to produce a finished product.
(2) The nut body 10 and the washer 30 are separately manufactured. The nut body 10 is a cold forged product.

(3) FIG. 6 is an explanatory view showing a method for manufacturing the wheel nut 1. When the cap 20 is fixed to the nut body 10, as shown in FIG. 6, the cap 20 and the nut body 10 are disposed in a press-fit mold 40 (press-fit mold including a push mold 41 and a receiving mold 42). The receiving die 42 has a tapered surface 42 a corresponding to the inclined portion 12 b of the flange portion 12 of the nut body 10, and the skirt portion 23 of the cap 20 can be deformed. The pressing die 41 has a hole 41 a corresponding to the cylindrical portion 14 of the nut body 10.

(4) Before press-fitting, the skirt portion 23 of the cap 20 has a predetermined inclination angle θ1, while the flange portion 12 of the nut body 10 has a predetermined inclination angle θ2. In the present embodiment, for example, the inclination angle θ1 is set to “30 degrees + 2.5 degrees to +5 degrees”, and the inclination angle θ2 is set to “30 degrees ± 1.5 degrees”.

(5) Further, before being press-fitted, the cylindrical portion 22 of the cap 20 has a predetermined L2 width (inner diameter) dimension L1, while the hexagonal portion 15 of the nut body 10 has a predetermined L2 width L2. Have In this embodiment, for example, L1 is set to "20-0.3 to -0.35 (mm)", and L2 is set to "20-0.15 to -0.25 (mm)".

(6) By being pressed by the pressing die 41, the cylindrical portion 22 of the cap 20 is press-fitted into the outer peripheral surface of the hexagonal portion 15 of the nut body 10 with an interference fit and fixed.
(7) When press-fitted, the skirt portion 23 of the cap 20 is pressed from the tip portion to the inclined portion 12b of the flange portion 12, and is deformed beyond the elastic deformation region to the plastic deformation region. By this deformation, an elastic force is generated in the skirt portion 23, and the skirt portion 23 is fixed in a state of being in close contact along the inclined portion 12b of the flange portion 12 by this elastic force.

  FIG. 7 is a “stress-strain diagram” showing the relationship between the stress and strain of a stainless steel plate (for example, austenite) used as the material of the cap 20. When the elastic deformation region is exceeded and the plastic deformation region is deformed, for example, when the force is removed at the point P, the elastic strain is reduced to become the strain of P1. The amount of elastic strain P2 to return to the original acts as a springback. That is, since the skirt portion 23 tries to return to the original state but is in contact with the inclined portion 12b of the flange portion 12, the force to return to the original acts as a pressing force.

  The deformation region of the skirt portion 23 may be within the elastic deformation region (although an elastic force having the effect of the present invention can be obtained), but by deforming beyond the elastic deformation region to the plastic deformation region, the following The effect is added and it is more desirable. In manufacturing the cap 20, it is desired to increase the inclination angle tolerance of the skirt portion 23. By doing so, it becomes easy to manufacture and the uniformity of manufacturing can be maintained. Therefore, by setting the inclination angle (inclination angle difference) of the skirt portion 23 to be large and deforming it to the plastic deformation region, it becomes possible to increase the inclination angle tolerance of the skirt portion 23. Therefore, the configuration utilizing the elastic strain in the plastic deformation region (in other words, the configuration utilizing the springback effect) is effective for both the production of the cap 20 and the cap fixing to the wheel nut 1.

  Further, in the hexagonal cylindrical portion 22 of the cap 20, the radius R1 of the hexagonal corner portion 22a is the same as or slightly larger than the radius R2 of the corner portion 15a of the hexagonal portion 15 of the nut body 10 ( For example, the relationship is 0.1 to 0.3 mm larger). The corners of the cap 20 are formed so as to satisfy the above-described relationship. When the cap 20 formed in this manner is press-fitted using the above-described press-fitting mold, the corner portion 22a of the cylindrical portion 22 of the cap 20 extends and closely contacts the corner portion 15a of the hexagonal portion 15 of the nut body 10. Presents.

  In this way, the skirt portion 23 of the cap 20 is formed in a sloped shape so as to move away from the cylindrical portion 22 in the radial direction, and the inclination angle formed by the skirt portion 23 and the direction perpendicular to the axis O of the cylindrical portion 22 of the cap 20 is formed. θ1 is set to be larger than an inclination angle θ2 formed by a direction perpendicular to the axis O of the hexagonal portion 15 of the nut body 10 and the inclined portion 12b, and the cylindrical portion 22 of the cap 20 is formed on the outer peripheral surface of the hexagonal portion 15 of the nut body 10. When press-fitting with an interference fit, the skirt portion 23 of the cap 20 is pressed and deformed by the inclined portion 12b of the flange portion 12, and is closely attached to the inclined portion 12b of the flange portion 12 by the elastic force due to the deformation of the skirt portion 23. Intrusion of water inside can be prevented. As described above, the liquid tightness between the cap 20 and the nut main body 10 can be improved, and it can also serve as a seal member. Since the elastic force of the skirt portion 23 is in close contact with the inclined portion 12b of the flange portion 12, it is possible to attach the cap 20 easily without the need for caulking and without the need for welding. As for the shape of the flange portion 12, the shape of the flange portion 12 can be freely made to some extent without forming any other structural restrictions by simply forming the inclined portion 12 b at the portion connected to the hexagonal portion 15.

  In addition, the lower end (tip) of the skirt portion 23 is positioned in front of the outer peripheral edge between the lower end of the hexagonal portion 15 and the outer peripheral edge of the flange portion 12, so that the end of the skirt portion 23 is formed. Without sticking out, it adheres along the flange portion 12 (the inclined portion 12b of the flange portion 12), is not caught, and is safe. Further, the lower end surface 23a of the skirt portion 23 is formed in a shape parallel to the axis O of the nut main body 10 so that the corner portion 23b has an obtuse angle, and the catch is further suppressed.

  Further, the radius R1 of the corner portion 22a of the cylindrical portion 22 of the cap 20 is press-fitted by being formed to be the same as or slightly larger than the radius R2 of the corner portion of the hexagonal portion 15 of the nut body 10. The corner portion 22a of the cylindrical portion 22 extends to improve the adhesion with the corner portion 15a of the hexagonal portion 15 of the nut body 10, and further improve the liquid tightness between the cap 20 and the nut body 10. Can do.

(Modification 1)
FIG. 8 shows a modification. The method of applying a load when pressing with a press-fitting type is different from that of the embodiment. 8 is pressed at a portion near the tip (outer peripheral edge) of the skirt 23 of the cap 20 (a position spaced radially inward from the outer peripheral edge of the skirt 23 and close to the outer peripheral edge). The crimping margin at the time of pressurization is formed circumferentially on the outer peripheral edge of the skirt 23. That is, when the cap 20 is press-fitted, it is pressed from the outside (outer peripheral edge), not from the portion (base portion) close to the tube portion 22 of the skirt portion 23. At that time, as shown in FIG. 8, it is desirable that the die (receiving die) 142 is in a state where the tip 23c of the skirt portion 23 is free (the die does not contact). Two forms can be shown as forms after press-fitting. FIG. 8B shows a form in which the inner peripheral side is in close contact so that no gap is formed, but the outer peripheral side has higher contact (surface pressure). FIG. 8C shows a form in which the outer peripheral side is in close contact and the inner peripheral side has a gap (the outer peripheral side is always in close contact). In FIG. 8, parts having the same functions as those in FIG.

  As the cap 20 is press-fitted in this manner, the contact between the outer peripheral portion of the skirt portion 23 and the inclined portion 12b of the flange portion 12 is improved. The tip 23c of the skirt portion 23 is in a free state, and the taper (inclination angle θ1) of the skirt portion 23 is larger than the taper (inclination angle θ2) of the inclined portion 12b of the flange portion 12. When the pressure is applied, the distal end portion 23c is moderately pressed against the inclined portion 12b of the flange portion 12, and the adhesion of the outer peripheral portion is improved. This can be said that the skirt portion 23 is pressed against the inclined portion 12b of the flange portion 12 in an elastically deformed state, and the close contact state between both is maintained by this elastic force.

(Modification 2)
FIG. 9 shows a second modification. In the second modification, the shape of the inclined portion of the nut body is changed. As shown in FIG. 9, in the vicinity of the outer peripheral edge of the inclined portion 112b of the nut body 110 (a position spaced radially inward from the outer peripheral edge of the inclined portion 112b of the flange portion 112 and close to the outer peripheral edge), A step 112c is formed. And the G part shown to Fig.9 (a) is pressurized, and the front-end | tip part 23c of the skirt part 23 of the cap 20 is made to engage and closely_contact | adhere to the step part 112c in the form along the step part 112c. . That is, when the cap 20 is press-fitted, the tip 23c of the skirt 23 is pressed against the step 112c via a predetermined jig, and is deformed along the step 112c to form an engaging portion ( (See FIG. 9B).

  In the modified example, as shown in FIG. 9, corrosion prevention due to battery action is performed circumferentially on the flange 112 facing surface side (the surface facing the inclined portion 112 b of the flange 112) of the tip portion 23 c of the skirt portion 23 of the cap 20. An insulating adhesive 125 is previously applied as an insulating member for press-fitting. This is because the cap 20 and the flange portion 112 are made of different metals (for example, the cap is made of a stainless steel plate, the flange portion (bolt body) is made of carbon steel, and the surface is galvanized or otherwise. For example, in the case of a structure coated with a metal coating material), it is intended to prevent the promotion of corrosion due to the contact effect at the contact portion. As the insulating member, a material having both insulating properties and waterproof properties is desirable. For example, an epoxy resin can be used as an insulating adhesive. After the press-fitting, as shown in FIG. 9C, the insulating adhesive 125 is formed in a laminated state between the tip 23c of the skirt 23 and the inclined portion 112b of the flange 112, and the insulating adhesive 125 is flanged. It is desirable that the portion 112 protrudes slightly from the end. Further, it is desirable that the end face 23a of the skirt portion 23 protrudes slightly longer outward in the radial direction than the end portion of the flange portion 112, thereby suppressing the flow of the adhesive toward the cap 20 side. The risk of damaging the aesthetics when viewed from above can be reduced. Thus, by forming an insulating layer with the insulating adhesive 125, a corrosion prevention effect can be added.

  As shown in FIG. 10, an engagement portion 23 d that engages with the stepped portion 112 c of the flange portion 112 is formed in advance on the outer peripheral portion of the skirt portion 23, and this engagement portion 23 d is used in the press-fitting process of the skirt portion 23. It can also be configured to fit into the stepped portion 112c. 9 and 10, parts having the same functions as those in FIG. 1 are denoted by the same reference numerals and description thereof is omitted.

  In this way, the tip 23c of the skirt portion 23 of the cap 20 is engaged with and closely contacts the step portion 112c in a form along the step portion 112c, and the outer peripheral portion of the skirt portion 23 is the step portion. By being in close contact with the inclined portion 112b ′ outside 112c (preferably pressed in an elastically deformed state), a double close contact effect between the inclined portion 112b ′ and the stepped portion 112c, and thus a kind of such bent contact surface Due to the labyrinth effect, water intrusion between the cap 20 and the flange portion 112 can be suppressed and rusting can be prevented. In the case of the example shown in FIG. 10, an insulating adhesive is applied in advance in the same manner as described above to the surface of the outer peripheral portion of the skirt 23 facing the inclined portion 112b ′ of the flange portion 112, before press-fitting. Thereafter, an insulating layer can be formed between the tip portion 23c of the skirt portion 23 of the cap 20 and the inclined portion 112b ′ of the flange portion 112. This can add a corrosion prevention effect.

In addition, you may add the following deformation | transformation to a present Example.
(1) Although the stainless steel plate was used as a material for the cap 20 in the present embodiment, the material is not limited to this, and any material having a high Young's modulus can be used, such as aluminum or titanium.
(2) The washer 30 is a tapered washer in the present embodiment, but is not limited to this, and for example, a plain washer may be used according to the shape of the hub side.

(3) The shape of the hexagonal portion 15 of the nut body 10 is not limited to the hexagonal shape, and various shapes can be adopted as long as it can engage with a tool such as a wrench and apply torque to the wheel nut 1. . For example, as shown in FIG. 11 (a), the nut body 50 has a circular outer periphery and a hexagonal hole 50a on the inside, or a plurality of tooth portions 55a on the outer periphery as shown in FIG. 11 (b). It is good also as the nut main body 55 which has (formed by serration). Correspondingly, the shape of the cylindrical portion 22 of the cap 20 can be changed.

(4) The insulating member provided between the skirt portion 23 of the cap 20 and the inclined portion 112b of the flange portion 112 is not limited to the example in which the step portion of the first modification is provided, and can be applied to others. For example, in FIG. 8, an insulating adhesive can be applied to the surface of the skirt portion 23 facing the inclined portion 12b of the tip 23c before press-fitting, and then press-fitted to form an insulating layer.

The front half sectional view and top view of the wheel nut of the present invention. The front half sectional view and top view of a nut main part. The front half sectional view and top view of a cap. The A section enlarged view of FIG. 3, and the B section enlarged view of FIG. Explanatory drawing which shows the manufacturing method of a cap. Explanatory drawing which shows the manufacturing method of a wheel nut. The stress-strain diagram showing an example of the relationship between the stress and strain of the cap material. Explanatory drawing which shows the modification of a wheel nut. Explanatory drawing which shows the other modification of a wheel nut. Explanatory drawing which shows the modification of the skirt part of FIG. Explanatory drawing which shows the modification of a nut main body.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Wheel nut 2 Hub 3 Disc wheel 4 Wheel bolt 10 Nut main body 11 Female thread part 12 Flange part 12b Inclined part (inclined surface)
15 Hexagonal part (tool engaging part)
15a Corner portion 17 Opening portion 20 Cap 21 Cap body portion 22 Tube portion 22a Corner portion 23 Skirt portion 23c Tip portion 112c Stepped portion

Claims (2)

A wheel nut for fastening the disc wheel to the hub on the vehicle body side,
A female screw portion that is screwed with a male screw portion of a wheel bolt provided on the hub side, and a pressure receiving surface that receives a fastening force by screwing with the wheel bolt, and a height from the pressure receiving surface on the opposite side to the pressure receiving surface There have a inner circumferential side inclined surface is the outer circumferential side becomes lower than the flange portion stepped portion is circumferentially formed on its outer peripheral edge, the tool engagement portion provided continuously on the inclined surface side of the flange portion A nut body having
A cap main body portion that closes the opening on the side opposite to the screwing start side of the female screw portion with the wheel bolt, and a cross-sectional shape similar to the cross-sectional shape of the tool engaging portion of the nut main body that is connected to the cap main body portion. A cylindrical portion that is press-fitted into the tool engaging portion with an interference fit and covers a side surface portion of the tool engaging portion, and radially outward from the cylindrical portion so as to face the inclined surface of the flange portion. And a cap having a skirt portion formed in a slope shape so as to be away from,
An inclination angle formed by a direction perpendicular to the axis of the cylinder portion of the cap and the skirt portion is formed larger than an inclination angle formed by a direction perpendicular to the axis of the nut body and the inclined surface of the flange portion, and the cap When the cylindrical portion is pressed into the outer peripheral surface of the tool engaging portion of the nut body with an interference fit, the skirt portion is pressed against the inclined surface of the flange portion and elastically deformed, and at least the outer peripheral portion of the skirt portion is It is closely attached to the inclined surface of the flange portion by an elastic force due to the elastic deformation, and the tip end portion of the skirt portion is in contact with the stepped portion in a form along the stepped portion. Wheel nut to be used. And the internal thread portion to be screwed with the male screw portion of the wheel bolt provided on the hub side for securing the disc wheel, have a pressure receiving surface for receiving the fastening force by screwing between its wheel bolt, on the opposite side to the pressure receiving surface A flange portion having an inclined surface whose height from the pressure receiving surface is lower on the outer peripheral side than the inner peripheral side, and having a stepped portion formed circumferentially on the outer peripheral portion of the inclined surface, and the inclined surface of the flange portion Forming a nut body provided with a tool engaging portion continuously provided on the side;
A cap main body that closes the opening on the side opposite to the screwing start side of the female screw portion with the wheel bolt, and a cross-sectional shape similar to the cross-sectional shape of the tool engaging portion of the nut main body that is connected to the cap main body A cylindrical portion that covers the side surface portion of the tool engaging portion, and a skirt portion that is formed in a slope shape so as to be radially outward from the cylindrical portion so as to face the inclined surface of the flange portion. An inclination angle formed between a direction perpendicular to the axis of the cylinder part and the skirt part is larger than an inclination angle formed between a direction perpendicular to the axis of the nut body and the inclined surface of the flange part, Forming a cap;
The cylindrical portion of the cap is an interference fit with the outer peripheral surface of the tool engaging portion of the nut body, and at least the outer peripheral portion of the skirt portion is in close contact with the inclined surface of the flange portion, and the tip of the skirt portion of the cap A press-fitting step of press-fitting the cap into the nut main body so that the portion is in a form along the stepped portion and is in close contact with the stepped portion ;
The manufacturing method of the wheel nut characterized by including this.

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