Resilient tires and wheels – Tires – resilient – Cushion and pneumatic combined
Reexamination Certificate
2000-05-26
2002-08-27
Morano, S. Joseph (Department: 3617)
Resilient tires and wheels
Tires, resilient
Cushion and pneumatic combined
Reexamination Certificate
active
06439282
ABSTRACT:
The present application is based on and claims priority from Japanese Patent Application Nos. HEI 11-148289 filed on May 27, 1999, HEI 11-170186 filed on Jun. 16, 1999, and 2000-89084 filed on Mar. 28, 2000, the contents of which are incorporated herein by reference.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a wheel with a damper for an automobile and the manufacturing method therefor.
2. Description of Related Art
In recent years, improving automobile fuel economy is important from the standpoint of protecting the global environment, and decreasing tire rolling resistance is strongly demanded. Among various resistance decreasing means, means for suppressing energy loss due to deformation of the side wall portion of the tire is effective. Accordingly, adoption of a highly pressurized tire and a low-profile tire which is low in height and has a small differential between an inside diameter and an outside diameter is increasing.
However, there are the following problems associated with a tire which is suppressed in deformation at the side wall portion, because a role a normal tire plays in suppressing a vibration transmission from a road to an automobile body decreases:
{circle around (1)} Ride quality lowers to cause a so-called bumpy feeling. The reason is that vibration in a vertical direction in the range of 10 Hz or higher is damped only a little compared with the case of a normal tire.
With an automobile mounted with a normal tire, vibration in the range of 10-12 Hz or higher is absorbed or damped by the tire, and vibration lower than 10-12 Hz including a floating and tilting feeling of the range of 5 Hz or less and vibrating feeling of the range of 5-12 Hz is absorbed or damped by a suspension system. However, with the highly pressurized tire and the low-profile tire, since the stiffness of the tire in the vertical direction increases, vibration in the range 10-30 Hz is slightly damped.
Japanese Patent Publication HEI 5-338401 proposes a wheel where a vibration insulating rubber is disposed between a rim and a disk. In the proposed wheel, the rubber acts as a vibrational barrier for insulating vibration due to the viscosity or viscous elasticity of the rubber, and therefore, the rubber does not act as a spring damper. Further, the rubber acts in compression and has too high spring constant to effectively damp the above-described bumpy feeling. With almost all of the other proposed wheels having a vibration insulating rubber disposed between a rim and a disk, the rubber is intended to act in compression and is too hard to effectively damp the bumpy feeling.
{circle around (2)} For the same reason as above, road noise (a noise hearing as “zaa” when a automobile runs on the road) increases. A vibration generated due to the road surface is transmitted to the body and vibrates the body panel to generate the road noise. Though the frequency range where the road noise appears changes according to a respective automobile, the road noise tends to appear in the range of 50-500 Hz from the general structure of an automobile. The road noise becomes particularly large in the vicinity of 250 Hz where the tire generates a columnar resonance.
{circle around (3)} Problems of instability in controllability arise.
More particularly, with a tire having a high rigidity at its tread such as a wide tire, the camber thrust force is small and the wheel tends to be drawn into a slanted portion of the road such as a wheel track. With a normal tire, since the gravitational force for drawing the wheel into the wheel track is negated by the camber thrust force, falling of the wheel into the wheel track does not tend to occur. Contrarily, with the tire having a high rigidity at its tread, since the tire tread is not easily deformed to the slant of the wheel track, the camber thrust force is too small to cancel out the effect of the gravitational force, so that falling of the wheel into the wheel track of the road easily occurs.
Further, with the conventional wheel where the rim and the disk are rigidly connected to each other, the road gripping force of the tire during rolling of the automobile decreases. When the automobile rolls due to a rapid turn, the automobile transversely inclines and a camber angle is generated between the automobile and the road surface. At the same time, the rim inclines and the tire inclines, and as a result, the road contact pressure of the tire becomes non-uniform in the width direction of the tire, and the road gripping force decreases. Thus, the force counteracting the centrifugal force also decreases, and despite efforts to steer the automobile during turning, the automobile tends to slip straight ahead. Conventionally, this slippage is prevented by the suspension system. However, when the rolling is large, the slippage cannot be prevented by the suspension system only.
Further, with the high performance tire such as a wide tire, a sudden ability to steer the automobile is likely to occur. A rising angle of the yaw rate (the yaw speed versus steering angle) of the high performance tire is large compared with that of the normal tire. Thus, with the high performance tire, steering suddenly works after a predetermined ineffective steering angle. If the high performance tire is mounted to the automobile which has been tuned for mounting the normal tire, the gain of steering is too great for the automobile to be steered, and a steering problem arises.
{circle around (4)} For compensating the imbalance and uniformity of the wheel, mounting a balancing weight to the wheel and the balancing the wheel are necessary.
{circle around (5)} With the wheel mounted with a rubber member between the rim and the disk, safety when the rubber member breaks should be maintained. Therefore, even if the rubber member breaks, the rim and the disk should not separate from each other, and even if even if the rubber member breaks, the rim and the disk should be able to transmit a drive torque and a brake torque between them. With almost all of the proposed wheels having the rubber member disposed between the rim and the disk, when the rubber member breaks, the drive torque and the brake torque are not transmitted between the rim and the disk any more. Therefore, such proposed wheels cannot be practically used.
SUMMARY OF THE INVENTION
An object of the invention is to provide a wheel with a damper for an automobile which can improve a ride quality.
Another object of the invention is to provide a wheel with a damper for an automobile which can suppress road noise as well as improve a ride quality.
Another object of the invention is to provide a wheel with a damper for an automobile which can improve steering controllability as well as ride quality.
Another object of the invention is to provide a wheel with a damper for an automobile which can attain self-alignment of the tire mounted wheel as well as improve ride quality.
Another object of the invention is to provide a wheel with a damper for an automobile which enables the automobile to operate safely for some distance even when a rubber member disposed between a rim and a disk breaks, as well as improve ride quality.
Another object of the invention is to provide a method for manufacturing with high productivity a wheel with a damper for an automobile capable of improving a ride quality.
The above objects can be performed by a wheel with a damper for an automobile and a method for manufacturing the same according to the invention as follows:
(1) A wheel with a damper for an automobile according to the present invention includes: a rim, a disk radially spaced from the rim, and a damper disposed between the rim and the disk. The damper has a rubber member having a spring constant. The spring constant of the rubber member of the damper is determined such that a first natural frequency of a vibrational system with a spring of the rubber member and a mass of the automobile is in a range of 6-12 Hz.
Preferably, the above wheel with a damper is constructed as follows:
(2) In the wheel with a damper of (1), the
Imamura Tadashi
Kimura Yoshiaki
Morano S. Joseph
Nguyen Long Bao
Topy Kogyo Kabushiki Kaisha
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