JP2001219707A - Fretting resistant multi-piece rim - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a multi-piece rim enabling it to enhance fretting resistant performance. SOLUTION: The multi-piece rim has a hardened layer K made of a martensite structure formed independently of in the whole by induction hardening in a lock ring groove 6; an O-ring groove 7; a contact part 4b of a side ring 4 with a bead sheet band 3; and a contact part 4f of the other side ring 4 with a back flange 1b.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multi-piece rim with improved fretting resistance, which is used for off-road wheels, for example, large and ultra-large wheels such as construction vehicles.

[0002]

2. Description of the Related Art FIG. 4 shows the structure of a general (conventional) multi-piece rim, where 1 is a rim base. Normally, the rim base 1 includes a gutter band 1a on one side in the axial direction, a back flange 1b on the other side in the axial direction, a center band 1c located at the center, and the like. The multi-piece rim includes a gutter band 1a having a lock ring groove 6 and an O-ring groove 7,
A lock ring 2 mounted in the lock ring groove and having one circumferential cut, a bead seat band 3 receiving an axial force by the lock ring 2, and a bead seat fitted on the outer peripheral side of the bead seat band to apply an axial force. The side ring 4 received by the band 3 and the axial force fitted on the outer peripheral side of the back flange 1b apply the axial force to the back flange 1b.
b and another side ring 4 received by b
The O-ring 5 is provided in the ring groove 7.

[0003]

When the multi-piece rim is actually mounted on a construction vehicle and driven, a constant surface pressure and a relative slip are repeatedly generated on the contact surfaces between the components, resulting in a rough contact surface. Damage occurs. This phenomenon is usually caused by the contact surface of the side ring 4 with the bead seat band 3, the contact surface of the side ring 4 with the back flange 1b,
And at the contact surface between the lock ring 2 and the lock ring groove 6 of the gutter band 1. This is generally called fretting. Fig. 5
As shown in (1), a fine crack d was generated from this, and FIG.
As shown in (2), it further develops into a large crack e,
It often progresses to destruction of members. Especially, gutter band 1
a of the lock ring groove 6 provided on the outer side in the axial direction.
The portion between the portion 6c and the side wall portion 6b is deformed outward by the repetitive load of the lock ring 2 in the direction A, so that the contact surface portion with the lock ring 2 becomes rough, and a fine crack due to fretting is generated. d is most likely to occur. In addition, a small crack d due to fretting is generated in the contact portion of the side ring 4 with the bead seat / sheet band 3 and the contact portion of the other side ring 4 with the back flange, and the gutter band 1a and the side ring 4 are broken. And the solution was sought. The easiest way to cope with these problems is to increase the thickness of the gutter band 1a and the side ring 4, but this method inevitably increases the weight of the multi-piece rim. Therefore, other countermeasures have been strongly desired to be developed in order to improve fuel efficiency and affect the load capacity.
SUMMARY OF THE INVENTION An object of the present invention is to provide an anti-fretting multi-piece rim that can increase the wear resistance and fatigue strength of a load receiving surface of a multi-piece rim, for example, a lock ring groove, a side ring load receiving surface, and prevent or suppress fretting. Is to do.

[0004]

The present invention to achieve the above object is as follows. (1) A gutter band that has a lock ring groove and an O-ring groove and constitutes one side in the axial direction of the rim base, a lock ring that is attached to the lock ring groove and has one cut in the circumferential direction, and an outer peripheral side of the gutter band. A bead seat band fitted to receive the axial force by the lock ring, a side ring fitted to the outer peripheral side of the bead seat band to receive the axial force by the bead seat band, and the other axial side of the rim base. A back flange, another side ring receiving an axial force by the back flange, and an O-ring disposed in the O-ring groove to seal between the gutter band and the bead seat band. In one rim, the surface layer of the lock ring groove is hardened by induction hardening, A fretting-resistant multi-piece rim, wherein a hardened layer having a site structure is formed. (2) A gutter band having a lock ring groove and an O-ring groove and constituting one side in the axial direction of the rim base, a lock ring mounted on the lock ring groove and having one circumferential cut, and an outer peripheral side of the gutter band. A bead seat band fitted to receive the axial force by the lock ring, a side ring fitted to the outer peripheral side of the bead seat band to receive the axial force by the bead seat band, and the other axial side of the rim base. A back flange, another side ring receiving an axial force by the back flange, and an O-ring disposed in the O-ring groove to seal between the gutter band and the bead seat band. In one rim, a hardened layer having a martensite structure by induction hardening, A fretting-resistant multi-piece rim formed on a surface portion of a contact portion of a side ring with the bead seat band and a surface portion of a contact portion of another side ring with the back flange. (3) The anti-fretting multi-piece rim according to (1), wherein a hardened layer having a martensite structure formed by induction hardening is formed on a surface portion of the O-ring groove.

In the multi-piece rim of the above (1), hardening having a martensitic structure by induction hardening is applied to the surface of the lock ring groove where the bottom end of the lock ring repeatedly contacts and the load is concentrated in the lock ring groove. Since the layer is formed, the fretting resistance is enhanced, the occurrence of microcracks is prevented, and the gutter band is prevented from being damaged without increasing the thickness of the gutter band, so that the durability of the multi-piece rim can be improved. In the multi-piece rim of the above (2), damage to the side ring is prevented, and the durability of the multi-piece rim can be improved. In the multi-piece rim of the above (3), in addition to the above (1), the damage of the O-ring groove is prevented, and the durability of the multi-piece rim can be improved.

[0006]

1 to 3 show an embodiment of the present invention. 1 to 3, the same parts as those in the conventional configuration shown in FIGS. 4 and 5 are denoted by the same reference numerals as in FIGS. As shown in FIGS. 1, 2 and 3, the multi-piece rim according to the embodiment of the present invention has a lock ring groove 6 and an O-ring groove 7 and constitutes one side of the rim base 1 in the axial direction.
a lock ring 2 which is fitted in the lock ring groove 6 and has one cut in the circumferential direction; a bead seat band 3 which is fitted on the outer peripheral side of the gutter band 1a and receives the axial force by the lock ring 2; A side ring 4 fitted on the outer peripheral side of the rim 3 and receiving the circumferential force by the bead seat band 3, a back flange 1b constituting the other axial side of the rim base 1, and another receiving the axial force by the back flange 1b. It has two side rings 4 and an O-ring 5 disposed in the O-ring groove 7 to seal between the gutter band 1a and the bead seat band 3. There are differences depending on the size of the multi-piece rim,
Usually, the gutter band 1a and the back flange 1b are welded and joined via at least one or more center bands 1c. However, they may be formed integrally. Gutter band 1a, bead seat band 3, side ring 4,
The O-rings 5 are respectively continuous in the circumferential direction, but the lock ring 2 has one cut in the circumferential direction, and both end portions of the ring are opposed to each other in the circumferential direction. Up to this point, the structure is the same as the conventional structure shown in FIGS.

FIG. 1 shows a contact portion between the surface layer portion 6f of the lock ring groove 6 and the bead seat band 3 of the side ring 4 which are subject to repeated loads and relative slips and are apt to cause fretting. As shown in FIG. 3, a hardened layer k having a martensitic structure is formed by induction hardening at 4a, a contact portion 4f of the side ring 4 with the back flange 1b. The hardened layer k having a martensite structure by induction hardening may be formed only in the lock ring groove 6 depending on the type of the multi-piece rim, or may be formed with the back flange 1b of the side ring 4 and the bead seat band 3. May be formed at each of the contact portions, or may be formed at all of the contact portions between the lock ring groove 6 and the back flange 1 b of the side ring 4 and the bead seat band 3. In addition, it is possible to perform heat treatment together with the formation of the hardened layer k in the lock ring groove 6 on the surface layer portion 7a of the O-ring groove 7 where a crack is rarely generated, but this is selected from the viewpoint of economy. You.

Next, a heat treatment method by induction hardening will be described. The objects subjected to induction hardening according to the present invention are the gutter band 1a and the side ring 4 having the lock ring groove 6 and the O-ring groove 7, each of which is heat-treated in a single piece, and later assembled as a multi-piece rim. The heat treatment method determines the coil shape that generates high frequency according to the shape of the target part to be heat treated, and the high frequency of the coil locally raises the surface layer temperature of the target part to the quenching temperature at which a martensitic structure can be obtained. Let
After that, water or the like is sprayed using a jacket or the like, and quenched by quenching.

Next, the advantage of using the high frequency heat treatment for the heat treatment of the anti-fretting multi-piece rim of the embodiment of the present invention will be described. (1) By devising a high-frequency coil, necessary local heating is possible. (2) Since only the surface layer can be heated, distortion of the component can be suppressed to a small value. (3) Heating can be performed in a short time. (4) Since the hardened layer on the surface can have a martensite structure and a compressive residual stress is generated, the fatigue strength of the multi-piece rim is improved. (5) A low carbon steel (C: 0.13% by weight or less) material is used for the multi-piece rim.
Hardness of about 300 or more is obtained, and wear resistance is improved. From the above, it was also confirmed by Examples that the surface of a necessary portion such as a multi-piece rim was hard and the inside was optimal for heat treatment of a product requiring toughness.

As a result of confirming the effect of this embodiment, according to an actual vehicle test, it is possible to obtain a hardened layer by forming a hardened layer having a martensite structure by induction hardening at a necessary portion, Because it can generate stress, compared to the conventional multi-piece rim without heat treatment,
It was confirmed that the strength for fretting resistance was improved twice or more. Further, since the hardened layer k was formed only in the surface layer portion, no adverse effect on the internal toughness occurred. In addition, it is possible to prevent the occurrence of micro-cracks due to fretting, and to prevent the progress of the micro-cracks from starting from the micro-cracks. Further, it was also confirmed that an effect was obtained and effective against corrosion fatigue of the lock ring groove, the O-ring groove, and the like.

[0011]

According to the multi-piece rim of the first aspect, the surface portion of the lock ring groove in the lock ring groove where the bottom end of the lock ring repeatedly contacts and the load is concentrated has a martensite structure by induction hardening. The formation of a hardened layer improves fretting resistance, prevents micro-cracks, and is effective against corrosion fatigue, preventing gutter band damage without increasing the gutter band thickness. The durability of the multi-piece rim can be improved. In the multi-piece rim according to the second aspect, damage to the side ring is prevented, and the durability of the multi-piece rim can be improved. In the multi-piece rim according to the third aspect, damage to the O-ring groove is prevented in addition to the first aspect, and it is also effective against corrosion fatigue, so that the durability of the multi-piece rim can be improved.

[Brief description of the drawings]

FIG. 1 is a partial cross-sectional view of a gutter band side of a multi-piece rim according to an embodiment of the present invention.

FIG. 2 is a partial cross-sectional view on the back flange side of the multi-piece rim according to the embodiment of the present invention.

FIG. 3 is a cross-sectional view showing a state in which a hardened layer is formed by induction hardening of a lock ring groove of a multi-piece rim according to an embodiment of the present invention.

FIG. 4 is a cross-sectional view showing a conventional multi-piece rim and the entire configuration of the present invention.

FIG. 5 is a cross-sectional view showing a structure near a lock ring groove of a conventional multi-piece rim.

[Explanation of symbols]

 1a Gutter band 1b Back flange 1c Center band 2 Lock ring 3 Bead seat band 4 Side ring 4a Contact portion of side ring with bead seat band 4f Contact portion of side ring with back flange 5 O-ring 6 Lock ring groove 7 O-ring groove k hardened layer

Claims (3)

[Claims] 1. A gutter band having a lock ring groove and an O-ring groove and constituting one side in the axial direction of a rim base; a lock ring attached to the lock ring groove and having one circumferential cut; and an outer periphery of the gutter band A bead seat band which is fitted to the side and receives an axial force by the lock ring; a side ring which is fitted on the outer peripheral side of the bead seat band and which receives the axial force by the bead seat band; and the other axial side of the rim base. A back flange that constitutes the following, another side ring that receives an axial force by the back flange, and an O ring that is disposed in the O ring groove and seals between the gutter band and the bead seat band. In the multi-piece rim, at least the surface of the lock ring groove is induction-fired. The Le, fretting Ohen rim, characterized in that to form a cured layer having a martensitic structure. 2. A gutter band having a lock ring groove and an O-ring groove and constituting one axial side of a rim base; a lock ring attached to the lock ring groove and having one circumferential cut; and an outer periphery of the gutter band A bead seat band which is fitted to the side and receives an axial force by the lock ring; a side ring which is fitted on the outer peripheral side of the bead seat band and which receives the axial force by the bead seat band; and the other axial side of the rim base. A back flange that constitutes the following, another side ring that receives an axial force by the back flange, and an O ring that is disposed in the O ring groove and seals between the gutter band and the bead seat band. In a multi-piece rim, hardening with a martensitic structure is performed by induction hardening. Characterized in that a layer is formed on a surface portion of a contact portion of the side ring with the bead seat band, and on a surface portion of a contact portion of the other side ring with the back flange, wherein the anti-fretting piece is formed. rim. 3. The anti-fretting multi-piece rim according to claim 1, wherein a hardened layer having a martensitic structure is formed on the surface of the O-ring groove by induction hardening.