JPH0529529Y2 - - Google Patents

Description

[Detailed explanation of the idea] [Purpose of invention]

(Industrial Application Field) This invention relates to an automobile wheel nut used when attaching an automobile disc wheel to the vehicle body, and is particularly applicable to an aluminum alloy wheel nut used for attaching a light alloy disc wheel such as an aluminum alloy. It's about Natsuto. (Prior Art) Conventionally, as described above, aluminum alloy wheel nuts have been produced by, for example, aluminum alloy bag nuts formed by cutting and machining JIS A7075-T6 material, and then anodized by anodizing. Some are coated with an oxide film (15μ to 20μ thick). (Problems to be solved by the invention) However, although the above-mentioned conventional aluminum alloy wheel nuts have good wear resistance and corrosion resistance, when used for a long period of time,
There is a problem in that the anodic oxide film, which has been colored in an appropriate tone, may change color due to heat or sunlight, resulting in a decrease in the appearance and design. In addition, with conventional aluminum alloy wheel nuts, when attaching a light alloy disc wheel to a vehicle body, when the aluminum alloy wheel nut is tightened to a preset torque to a hub bolt on the vehicle body side, an axial force is generated between the two. However, it changes significantly each time tightening is repeated, so over- or under-tightening of the aluminum alloy wheel nut will not cause problems with the mounting condition of the light alloy disc wheel. The problem is that there is no. Furthermore, when conventional aluminum alloy wheel nuts are used, for example, on aluminum alloy disc wheels, they are designed to prevent galling (so-called "togane") between aluminum alloy disc wheels. It was necessary to press fit a steel nut seat into the wheel side. (Purpose of the invention) This invention was made by focusing on the problems mentioned above, and it not only prevents wear and corrosion but also prevents discoloration, and does not maintain any appearance or design even after long-term use. In addition, since the predetermined axial force is obtained by the set tightening torque, there will be no problem with the mounting condition of the light alloy disc wheel. The purpose of the present invention is to provide an aluminum alloy wheel nut that does not require press-fitting a nut seat made of aluminum alloy.

[Structure of the idea]

(Means for solving the problem) The structure of the aluminum alloy wheel nut according to this invention is that an anodized film and a wax film are laminated on the entire surface of an aluminum alloy bag nut finished in a predetermined wheel nut shape. It is characterized by the fact that In this case, the aluminum alloy used for the aluminum alloy bag nut used in the aluminum alloy wheel nut of this invention is JIS A7075-T62 material or JIS A7075-T62 material.
T73 material is available, but it is less prone to stress corrosion cracking.
It is more desirable to use JIS A7075-T73 material. In addition, the wax used in the wax coating of the aluminum alloy wheel nut of this invention is
A material with good spreadability is desirable, and a silica/polyvinyl acetal composite consisting of a polyvinyl acetal and an alkyl (or allyl) silicate is particularly desirable. (Example) This invention will be explained below based on the drawings. 1 to 3 show an aluminum alloy wheel nut according to an embodiment of this invention. That is, as shown in FIGS. 1 and 2,
The aluminum alloy wheel nut 1 includes a spherical part 2 that comes into contact with a nut seat formed on a disc wheel made of a light alloy such as an aluminum alloy, a large diameter part 3 formed continuously with the spherical part 2, and a hexagonal head. 4, and a small diameter part 6 is formed between the collar part 5 formed on the spherical part 2 side of the head 4 and the large diameter part 3, into which the washer W shown in phantom line is fitted. There is. Further, as shown in FIG. 3, the aluminum alloy wheel nut 1 is colored in an appropriate color on the entire surface including the internal threaded portion 7 formed inside from the spherical portion 2 to the vicinity of the tip of the head 4. By providing an anodic oxide film 8 (film thickness 15μ to 20μ),
It is designed to prevent corrosion and wear. moreover,
The aluminum alloy wheel nut 1 is provided with a wax film 9 laminated on the entire surface of the anodic oxide film 8, so that the anodic oxide film 8, which is colored in an appropriate tone, will discolor or fade due to heat or sunlight. It is designed so that it can be prevented. The wax used for the wax film 9 is a mixture of 15% ethanol solution of polyvinyl butyral, ethyl polysilicate, and 40% phosphoric acid aqueous solution in 5 parts.
A silica composite obtained by reacting at a ratio of 1:0.2 was adjusted to a viscosity of 50 cP (centipoise) with ethanol. Aluminum alloy wheel nut 1 mentioned above
When manufacturing a cylindrical aluminum alloy (JIS A7075-O material in this example), it is cold forged into the specified external shape of a wheel nut, subjected to T73 heat treatment, and then rolled. A female threaded portion is formed using the aluminum alloy bag nut. Next, this aluminum alloy bag nut is anodized to form an anodized film 8 on its entire surface and colored in an appropriate color tone, and the wax is further laminated on the entire surface of this anodized film 8 to form a wax film. form 9. Therefore, when manufacturing this aluminum alloy wheel nut 1, an aluminum alloy wheel nut 1 without a wax coating 9 laminated thereon and an aluminum alloy wheel nut 1 laminated with a predetermined wax coating 9 were exposed to sunlight for a long period of time. When exposed to water, discoloration was observed in the anodic oxide film 8 of the aluminum alloy wheel nut that was not laminated with the wax film 9;
Aluminum alloy wheel nut 1
No discoloration was observed in the anodic oxide film 8 at all. Therefore, it was verified that the aluminum alloy wheel nut 1 according to this invention has excellent discoloration resistance. Further, the aluminum alloy wheel nut 1 according to this invention is connected to a bolt connected to a load cell via a washer and a disc wheel (made of steel), and the operations of tightening and returning the aluminum alloy wheel nut 1 are repeated. When a test was conducted and the relationship between the torque and the axial force generated at that time was investigated, the results shown by the solid line in FIG. 4 were obtained. For comparison, the above test was conducted on a wheel nut made of steel (S25C material), which is currently widely used, and the results shown by the dotted line in FIG. 4 were obtained. From the above test results, in the aluminum alloy wheel nut 1 according to the present invention, even if the tightening and returning operations are repeated, there is little variation in the axial force generated against the set torque (for example, when the torque is 12Kgf-m). On the other hand, the variation in axial force is
400Kgf) and the variation in the case of steel wheel nuts (the variation in axial force was 1200Kgf for a torque of 12Kgf-m), it was proved that the reproducibility was good. Furthermore, the aluminum alloy wheel nut 1 according to this invention is an aluminum alloy (AC4C material; for casting) that does not have a steel nut seat.
When used on a disc wheel made of (Al-Si-Mg alloy), galling occurred between the two.
did not occur. At this time, apply vibration (amplitude 1.5 mm, frequency 20 Hz) to the above disc wheel,
When a change in axial force, that is, a loosening test of the aluminum alloy wheel nut 1, was conducted, the results shown by the solid line in FIG. 5 were obtained. In this case as well, when the above test was conducted using a steel wheel nut for comparison, the results shown by the dotted line in FIG. 5 were obtained. The upper part of Figure 5 shows the loosening when tightened with an axial force of about 1800 kgf, and the lower part shows the loosening when tightening with an axial force of about 900 kgf. Therefore, the aluminum alloy wheel nut 1 according to this invention can be directly tightened onto an aluminum alloy disc wheel without requiring a steel nut seat. As shown, it was found that even when the disc wheel was subjected to vibration, there was very little slack. Note that the shape of the aluminum alloy wheel nut in this invention is not limited to the shape of the aluminum alloy wheel nut 1 according to the above-described embodiment.

[Effect of the idea]

As explained above, the aluminum alloy wheel nut according to this invention has a structure in which an anodized film and a wax film are laminated on the entire surface of an aluminum alloy bag nut finished into a predetermined wheel nut shape. As a result, it is possible to prevent not only wear and corrosion but also discoloration and fading, and even after repeated use for a long period of time, there is no loss of appearance and design. Since the power can be obtained, it is possible to prevent problems with the installation of the light alloy disc wheel, and in addition, there is no need to interpose a steel nut seat between the light alloy disc wheel and the light alloy disc wheel. This has the excellent effect of making it possible to

[Brief explanation of drawings]

Fig. 1 and Fig. 2 are a side view and a plan view, respectively, showing an aluminum alloy nut according to one embodiment of the present invention, Fig. 3 is a cross-sectional view taken along line A-A in Fig. 1, Fig. 4 is a graph showing the relationship between axial force and torque when the aluminum alloy wheel nut shown in Fig. 1 and a steel wheel nut for comparison are fastened to a steel disk wheel, and Fig. 5 is a graph showing the change in axial force when vibration is applied to an aluminum alloy disk wheel fastened to the aluminum alloy wheel nut shown in Fig. 1 and a steel wheel nut for comparison.
...Anodized coating, 9...Wax coating.

Claims (1)

[Scope of utility model registration request] Anodized coating is applied to the entire surface of the aluminum alloy bag nut finished in the specified wheel nut shape.
An aluminum alloy wheel nut characterized by being made by laminating a wax film.