JP2009096355A - Wheel cap - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a wheel cap capable of preventing formation of shrink marks on a plate 1 and also preventing a wavy deformation thereof after molding or heating while allowing formation of minute welds. <P>SOLUTION: A gap 30 is formed at least between portions where claws 3 protrude and the plate 1 on a peripheral wall 2, and a separation portion 4 formed from a gap 40 and a slip 41 which separates, in both circumferential directions, the peripheral wall 2 where adjacent claws 3 are coupled to each other. The separation portion 4 weakens the rigidity of the peripheral portion 2, thus reducing a difference in the strength between the peripheral wall 2 and the plate 1. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a wheel cap mounted on a tire wheel of an automobile.

  A wheel cap for improving appearance design is detachably attached to a tire wheel of an automobile. This wheel cap is composed of a disk-shaped plate portion and a plurality of claw portions that integrally project from the back side of the plate portion, and is generally manufactured by injection molding.

  This wheel cap has a metal ring engaged and held on the inner periphery of the claw, and can be attached to and removed from the tire wheel by urging the claw part radially outward by the elasticity of the metal ring and pressing it against the tire wheel. It is attached to. Therefore, it is necessary to increase the rigidity of the claw portion. For example, it is conceivable to design the claw portion to be thick. However, when the nail portion is thick, there is a problem that sink marks are generated on the surface of the plate portion and the design properties are impaired.

  Japanese Patent Application Laid-Open No. 07-149104 proposes a wheel cap in which a rib extending in the circumferential direction is formed on the back side of the plate portion, and a crimping piece corresponding to the claw portion is formed on the rib. In the technique described in the publication, a leg portion rising from the edge of the rib is formed, and a locking piece and a crimping piece are formed on the upper edge of the leg portion. And a metal ring is hold | maintained between a locking piece and a crimping piece, and a crimping piece is crimped | bonded to a tire wheel with the elasticity of a metal ring. Accordingly, the claw portion is formed on the upper edge of the leg portion, and the occurrence of sink marks can be suppressed as compared with the case where it is directly formed on the plate portion.

  Japanese Patent Application Laid-Open No. 07-096703 also discloses a wheel cap in which a rib extending in the circumferential direction is formed on the back side of the plate portion, and a claw portion is formed on the rib.

  However, as described in these publications, even if the claw portion is formed on the rib extending in the circumferential direction, it is inevitable that a certain amount of sink occurs in the plate portion at the position where the claw portion is formed.

  Further, from the viewpoint of design or from the viewpoint of heat dissipation, a decorative hole penetrating the front and back is often formed in the plate portion. In injection molding, a gate is generally provided at the center of the plate portion. In such a wheel cap, a weld portion where the resin flows merge is formed at the outer peripheral portion of the decorative hole at the peripheral portion of the plate portion.

  On the other hand, a wheel cap molded using a resin containing a reinforcing material such as glass fiber in order to increase rigidity is known. However, in a wheel cap formed using a resin containing a fibrous reinforcing material such as glass fiber, the orientation of the reinforcing material is disturbed, and thus a phenomenon occurs in which the strength of the weld portion is lower than that of other parts. On the other hand, the rib extending in the circumferential direction has high strength against deformation in the circumferential direction. Therefore, there has been a problem that the plate portion is wavy and deformed due to shrinkage during cooling after molding, or due to heat in the drying process after coating and heat history during use.

As a solution to this problem, Japanese Patent Application Laid-Open No. 2000-108167 discloses that a mold structure for molding a wheel cap having a decorative hole is devised to control the flow rate of the resin, thereby generating a weld portion. It has been described that the above has been suppressed. However, in the method in which the flow rate of the resin is controlled by the mold structure, a weld portion may be generated depending on fluctuations in the temperature or injection pressure of the molten resin, and it is difficult to eliminate the weld portion.
JP 07-149104 A Japanese Patent Laid-Open No. 07-096703 JP 2000-108167 A

  The present invention has been made in view of the above circumstances, and while suppressing the occurrence of sink marks in the plate portion, the plate portion after molding or after thermal history is allowed while allowing the formation of a minute weld portion. It is a problem to be solved to suppress wavy deformation.

  A feature of the wheel cap of the present invention that solves the above problem is a wheel cap formed by injection molding from a resin containing a fibrous reinforcing material, and is integrally formed from the disk-shaped plate portion and the back surface side of the plate portion. A plate having a ring-shaped peripheral wall portion that protrudes and a plurality of claw portions that are formed integrally with the peripheral wall portion and spaced apart from each other in the circumferential direction, and at least a portion of the peripheral wall portion from which the claw portion protrudes and a plate A gap is formed between the part, and a part of the peripheral wall part that connects adjacent claws is formed between the peripheral wall part and the plate part, and a slit that separates the peripheral wall part in the circumferential direction. That is, a separation portion formed of a gap is formed.

  It is desirable that the separation part is opposed to the weld part formed in the plate part at the time of molding.

  According to the wheel cap of the present invention, a gap is formed between at least a portion of the peripheral wall portion where the claw portion protrudes and the plate portion. Therefore, even if the claw portion is formed thick, it is possible to effectively suppress the occurrence of sink marks in the plate portion and to secure the rigidity of the claw portion.

  A part of the peripheral wall part that connects the adjacent claw parts is formed with a separation part including a gap formed between the slit for separating the peripheral wall part and the plate part. That is, the peripheral wall portion is separated in the circumferential direction by the separation portion. Therefore, since the rigidity of the peripheral wall portion is reduced due to the presence of the separation portion, the difference in strength between the peripheral wall portion and the plate portion is reduced, and the undulation deformation of the plate portion due to shrinkage or thermal history during molding can be suppressed.

  Further, if the separation portion faces the weld portion, the separation portion is disposed at the same position in the circumferential direction as the weld portion that is the starting point of the deformation, so that the wavy deformation of the plate portion can be more reliably prevented. .

  Furthermore, according to the wheel cap of the present invention, since the generation of a minute weld portion is allowed, it is not necessary to devise a mold structure, and an increase in man-hours can be prevented.

  The wheel cap of this invention has a plate part, a surrounding wall part, and a nail | claw part. The plate portion has a disk shape and has at least a valve hole for exposing the tire valve. From the viewpoint of the design surface or heat dissipation, it is preferable to form a decorative hole penetrating the front and back.

  The peripheral wall portion is a rib-like member that integrally protrudes from the back surface side of the plate portion, and is formed in a ring shape that goes around in the circumferential direction. A plurality of claw portions that are spaced apart from each other in the circumferential direction are formed on the peripheral wall portion. The plurality of claws are attached to the tire wheel by having a metal ring engaged and held on the inner peripheral side thereof and being pressed against the rim of the tire wheel by the elasticity of the metal ring.

  In the wheel cap of the present invention, a gap is formed between at least a portion of the peripheral wall portion where the claw portion protrudes and the plate portion. That is, at least at the portion where the claw portion protrudes, the peripheral wall portion and the back surface of the plate portion face each other with a gap therebetween, and the peripheral wall portion is in a state of floating from the plate portion. Therefore, even if the nail portion is formed thick, the occurrence of sink marks on the surface of the plate portion is prevented, and high designability is exhibited. In addition, there is no restriction | limiting in particular in the magnitude | size of a clearance gap, In view of the rigidity of a nail | claw part and a surrounding wall part, it can select in the range which does not produce a malfunction in the detachability of a wheel cap to the tire wheel.

  In the wheel cap of the present invention, a separation portion is formed in a part of the peripheral wall portion that connects adjacent claw portions. The separation portion includes a slit that separates the peripheral wall portion in the circumferential direction, and a gap formed between the peripheral wall portion and the plate portion. That is, the separation part is in a state of floating from the plate part, and the peripheral wall part is separated in the circumferential direction by the slit. Accordingly, the strength difference between the peripheral wall portion and the plate is reduced, and the wavy deformation of the plate portion due to shrinkage or thermal history during molding can be suppressed.

  The width of the slit is desirably 1 mm or less. When the slit is larger than 1 mm, the strength of the peripheral wall portion is greatly decreased and the rigidity of the claw portion is decreased. Further, the size of the gap in the separation portion can be selected within a range in which there is no problem in the detachability of the wheel cap to the tire wheel in consideration of the rigidity between the claw portion and the peripheral wall portion.

  The wheel cap of the present invention is formed by injection molding from a resin containing a fibrous reinforcing material. As the fibrous reinforcing material, glass fiber, ceramic fiber, cellulose fiber or the like can be used. The content may be the same as the conventional one. Further, the type of resin is not particularly limited, and those similar to conventional ones such as PP and polyamide can be used.

  Further, the inventors of the present invention provide a fiber cap with a wheel cap having a gap between at least a portion of the peripheral wall portion where the claw portion protrudes and the plate portion, and a weld portion on the plate portion facing the gap. When molding was performed using a resin containing a material, a problem was found that undulation deformation occurred in the plate portion after molding. The reason for this is that in the weld part formed in the plate part, the orientation of the reinforcing material is disturbed by the joining of the resins, so the rigidity in the circumferential direction is lower than other parts, the rigidity in the circumferential direction of the peripheral wall part is high, molding It is considered that the weld portion becomes the starting point of deformation due to the tensile stress during the subsequent cooling.

  However, according to the wheel cap of the present invention, the separation portion having the slit for separating the peripheral wall portion in the circumferential direction is provided, and the separation portion faces the weld portion. Accordingly, the stress difference between the peripheral wall portion and the plate portion during cooling after molding is reduced due to the decrease in rigidity of the peripheral wall portion, and the wavy deformation of the plate portion can be suppressed.

  In addition, it is preferable that the position of the slit is a position facing the weld portion formed in the plate portion. However, in some cases, the position does not have to be opposed to the weld portion.

  And according to the wheel cap of the present invention, it can be attached / detached even when the swinging dimension of the claw portion at the time of attachment / detachment fluctuates due to an error in manufacturing, compared to the wheel cap similar to the present invention except that it has no slit. It became clear that the fluctuation range of the load was small. That is, it has been clarified that the wheel cap of the present invention has a stable load when being attached to and detached from the tire wheel. This is an effect due to the formation of the slit, and it is considered that the rigidity due to the cooperation between the claw portion and the peripheral wall portion is stabilized by the slit.

  Hereinafter, the present invention will be specifically described with reference to Examples and Comparative Examples.

Example 1
The wheel cap of a present Example is shown in FIGS. This wheel cap is formed by injection molding from a polypropylene resin containing glass fibers.

  The wheel cap includes a disc-shaped plate portion 1, a ring-shaped peripheral wall portion 2 that protrudes integrally with the plate portion 1 from the back side of the plate portion 1, and a plurality of the peripheral cap portions 2 spaced apart from each other in the circumferential direction. And a formed claw portion 3.

  The plate part 1 has five first decorative holes 10 penetrating the front and back at an equal angle, and two spoke parts 11 extending radially from the center of the plate part 1 between the first decorative holes 10. Each is formed. A second decorative hole 12 extending radially is formed between the two spoke portions 11.

  At the time of injection molding, a gate is formed at the center of the plate portion 1 and the molten resin flows from the center of the plate portion 1 toward the outer peripheral direction. Accordingly, the molten resin flows around the first decorative hole 10 and the second decorative hole 12 and joins on the outer peripheral side of the first decorative hole 10 and the second decorative hole 12, so that the first decorative hole 10 and the second decorative hole 10 A weld portion is formed on the outer peripheral side of the decorative hole 12.

  The peripheral wall portion 2 is formed in a rib shape that makes one round in the circumferential direction along the peripheral edge of the plate portion 1, and a part thereof constitutes the outer peripheral wall of the first decorative hole 10. And the claw part 3 protrudes in the axle direction at the surrounding wall part 2 located in the back surface side of the two spoke parts 11, respectively.

  In the peripheral wall portion 2, ribs 13 between the claws are formed on both sides of each claw portion 3, and a metal ring (not shown) is held between the outer peripheral side surface of the interclaw rib 13 and the inner peripheral surface of the claw portion 10. Is done. The claw ribs 13 on one side of the claw 3 are connected to the peripheral wall 2 constituting the outer peripheral wall of the first decorative hole 10. The other inter-claw rib 14 is disposed adjacent to the outer peripheral side of the second decorative hole 12 together with the inter-claw rib 14 formed on one side of the adjacent claw portion 3. A gap 30 is formed between the portion of the peripheral wall portion 2 where the claw portion 3 protrudes and the back surface of the plate portion 1 as shown by the hatched portion in FIG. The claw ribs 13 and 14 protrude from the plate portion 1 and are integrated with the peripheral wall portion 2.

  Separating portions 4 are formed between the inter-rib ribs 14 arranged adjacent to the outer peripheral side of the second decorative hole 12. The separation portion 4 has a plate shape that constitutes a part of the circumferential wall portion 2 in the circumferential direction. A gap 40 similar to the gap 30 is formed between the separation part 4 and the back surface of the plate part 1 as shown by the hatched part in FIG. The separation portion 4 is formed with a slit 41 having a width of 1 mm extending in the axle direction, and the peripheral wall portion 2 is separated in the circumferential direction at the position of the slit 41. The slits 41 are opposed to the welds 15 formed on the outer periphery of the second decorative hole 12, respectively.

  The slits 41 are respectively formed between a plurality of pairs of inter-claw ribs 14 existing on the outer periphery of the plurality of second decorative holes 12.

(Comparative Example 1)
A wheel cap similar to that of Example 1 except that the slit 41 was not provided was used as Comparative Example 1.

<Test Example 1>
About the wheel cap of the said Example 1 and the comparative example 1, the dimensional accuracy in the new state after a shaping | molding was measured. As shown in FIG. 4, each wheel cap is attached to the same tire wheel 101 using the same metal ring 100, and the outer peripheral positions (a of the first decorative hole 10 and the second decorative hole 12 at that time are shown in FIG. The distance (mm) (distance L in FIG. 4) between the outer peripheral edge of the plate portion 1 and the tire wheel at the 10 points of .about.j is measured at three locations, and each deviation (maximum distance and minimum) is measured. The difference from the distance was calculated. The results are shown in Table 1.

  From Table 1, it is clear that the wheel cap of Example 1 has a smaller deviation than the wheel cap of Comparative Example 1. By forming the slit 41, the wavy deformation of the plate part 1 due to shrinkage after molding is suppressed. It is clear that

<Test Example 2>
Each of the wheel caps of Example 1 and Comparative Example 1 was coated and dried by heating at 80 to 120 ° C. for 10 to 30 minutes. Thereafter, in the same manner as in Test Example 1, the distance in the axle direction between the outer peripheral end of the plate portion 1 and the tire wheel was measured, and the respective deviations were calculated. The results are shown in Table 2.

  From Table 2, the wheel cap of Comparative Example 1 shows the same result as Test Example 1 even after the thermal history. On the other hand, in the wheel cap of Example 1, although the deformation has progressed from the case of Test Example 1 due to the thermal history, the deviation is slightly smaller than that of Test Example 1 compared to the wheel cap of Comparative Example 1, and It is even smaller than that.

  That is, in the wheel cap of Comparative Example 1, the deformation at the time of cooling after molding is maintained as it is, whereas the deformation of the wheel cap of Example 1 is slightly advanced by forming the slit 41, but the deviation is reduced. It turns out that it changed in the direction to do.

<Test Example 3>
A plurality of wheel caps of Example 1 and Comparative Example 1 were respectively formed, and an assembly load and a removal load when the same tire wheel was mounted using the same steel metal ring were measured. Assembly and removal were performed multiple times for each wheel cap, and the average value was used as the assembly load or removal load. Moreover, the difference (tightening allowance) between the outer diameter of the claw part 3 of each wheel cap and the inner diameter of the part where the outer peripheral surface of the claw part 3 contacts in the tire wheel was measured.

  The results are shown in FIG. 5 with the tightening margin on the horizontal axis and the load on the vertical axis.

  FIG. 5 shows that the relationship between the tightening allowance and the load is a linear relationship, and the inclination of the wheel cap of Example 1 is smaller than that of the wheel cap of Comparative Example 1. That is, even if the swinging dimension (tightening allowance) of the claw portion during attachment / detachment varies due to manufacturing errors, the wheel cap of Example 1 has a smaller fluctuation range of the attachment / detachment load than the wheel cap of Comparative Example 1, and the attachment / detachment The load is stable. This is an effect due to the formation of the slit 41, and it is considered that the rigidity due to the cooperation of the claw portion 3 and the peripheral wall portion 2 is stabilized by the slit 41.

(Other aspects of Examples)
In the above embodiment, the separation part 4 is formed at a position facing the weld 15, but a slit may be formed on the peripheral wall part 2 facing the gap 30 with the gap 30 as a part of the separation part 4. That is, as shown in FIG. 6, a slit 31 may be formed in the peripheral wall portion 2 facing the gap 30 between the inter-claw rib 14 and the claw portion 3, or as shown in FIG. You may form the slit 32 in the surrounding wall part 2 which opposes the clearance gap 30 between the nail | claw parts 3. FIG. It is also possible to form these in combination with the slit 41 shown in the first embodiment. However, in these cases, rigidity due to cooperation between the claw portion 3 and the peripheral wall portion 2 to which the claw portion 3 is connected may be insufficient. It is desirable to form the slits 41 only in the case.

It is a top view of the design surface side of the wheel cap which concerns on one Example of this invention. It is a top view of the back surface side of the wheel cap which concerns on one Example of this invention. It is a principal part side view of the wheel cap which concerns on one Example of this invention. It is principal part sectional drawing of the wheel cap which concerns on one Example of this invention. It is a graph which shows the relationship between a fastening allowance and a load. The other aspect of an Example is shown and it is a principal part side view of a wheel cap. The other aspect of an Example is shown and it is a principal part side view of a wheel cap.

Explanation of symbols

1: Plate part 2: Peripheral wall part 3: Claw part 4: Separation part 15: Weld part 30: Clearance
40: Clearance 41: Slit

Claims (3)

A wheel cap formed by injection molding from a resin containing a fibrous reinforcing material, a disk-shaped plate portion, a ring-shaped peripheral wall portion integrally projecting from the back side of the plate portion, and the peripheral wall portion A plurality of claw portions that are integrally formed and spaced apart from each other in the circumferential direction,
A gap is formed between at least the portion of the peripheral wall portion where the claw portion is formed and the plate portion,
A part of the peripheral wall part that connects the adjacent claws to each other includes a slit that separates the peripheral wall part in the circumferential direction and a gap formed between the peripheral wall part and the plate part. A wheel cap characterized in that a portion is formed.   The wheel cap according to claim 1, wherein the separation portion faces a weld portion formed in the plate portion during molding. The wheel cap according to claim 1 or 2, wherein the slit has a width of 1 mm or less.

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