Joints and connections – Molded joint – Fusion bond – e.g. – weld – etc.
Reexamination Certificate
1999-09-01
2001-12-04
Kim, Harry C. (Department: 3629)
Joints and connections
Molded joint
Fusion bond, e.g., weld, etc.
C403S335000, C228S112100
Reexamination Certificate
active
06325567
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an arm member for use as, for example, an automobile suspension arm or an engine mount, and more particularly, to an arm member which is to be coupled with the other members and includes a coupling member with a bushing mounting portion, a yoke portion, a ball joint mounting portion, or the like.
The term “aluminum” used in this specification denotes aluminum and its alloys.
2. Description of the Related Art
FIGS. 8A and 8B
illustrates an arm member
51
for use as an automobile suspension arm such as an upper arm, a lower arm, a trailing arm and a torsion arm.
The arm member
51
comprises a main body
52
and a pair of metallic coupling members
55
each connected to the respective end portion
53
of the main body
52
. The main body
52
is made of a metallic cylindrical pipe having a predetermined length in order to lighten the arm member
51
.
The coupling member
55
comprises a cylindrical bushing mounting portion
57
for mounting a columnar vibroisolating bushing
61
with a rubber elastic member, a columnar connecting portion
58
integrally outwardly protruded from an outer surface of the bushing mounting portion
57
, and a columnar fitting protrusion
59
integrally outwardly protruded from the central portion of the end surface of the connecting portion
58
. The fitting protrusion
59
has a diameter smaller than that of the connecting portion
58
. The bushing mounting portion
57
has a circular bushing mounting opening
56
. The vibroisolating bushing
61
is forcibly fitted in the bushing mounting opening
56
and secured therein.
In this arm member
51
, as shown in
FIG. 8B
, the stepped end of the connecting portion
58
of the coupling member
55
is abutted to the end of the peripheral wall at the end portion
53
of the main body
52
to form an abutted portion
60
. The coupling member
55
is connected to the main body
52
at the abutted portion
60
. In this state, the fitting protrusion
59
of the coupling member
55
is tightly fitted in or forcibly fitted in the opening
52
a
of the end portion
53
of the main body
52
. In
FIG. 8B
, the portion W′ is a welded portion formed along the entire circumference of the abutted portion
60
.
For joining the abutted portion
60
, various joining methods can be adapted, such as a fusion welding method including a MIG welding, a TIG welding or a laser welding, or a friction agitation joining or welding method (hereinafter referred to as “friction agitation joining method) which is one type of solid-phase joining (welding) methods. In the arm member
51
shown in
FIGS. 8A and 8B
, the abutted portion
60
is joined, or welded, by a friction agitation joining method.
The friction agitation joining method will be explained as follows. In
FIG. 8B
, the reference numeral
70
denotes a joining tool for a friction agitation joining method. The joining tool
70
includes a columnar rotor
71
having a larger diameter and a pin-like probe
72
having a smaller diameter protruded from an end surface
71
a
of the rotor
71
along the axis of the rotor
71
. The probe
72
rotates as the rotor
71
rotates. The rotor
71
and the probe
72
are harder than the main body
52
and the coupling member
55
, and made of heat-resistant materials which can stand friction heat generated during the joining process. Convex portions (not shown) for agitating or stirring the softened materials are formed on the surface of the probe
72
.
In the arm member
51
, the main body
52
and the coupling member
55
are joined according to the following steps. First, while rotating the probe
72
on the rotor
71
of the joining tool
70
, the rotating probe
72
is inserted into the abutted portion
60
. Then, the rotating probe
72
is moved in the circumferential direction of the abutted portion
60
while softening and agitating the portion where the rotating prove
72
contacts by the friction heat. Thus, the abutted portion
60
is joined, or welded, along the entire circumference thereof. As a result, the coupling members
55
are coupled to the main body
52
.
The arm member
51
is to be connected to the other member of an automobile (not shown) via the vibroisolating bushing
61
mounted in the bushing mounting opening
56
of the coupling member
55
. Therefore, the main body
52
and the coupling members
55
must be joined firmly.
However, a conventional arm member, in which the main body and the coupling member are joined by a joining method such as a fusion welding (a MIG welding, a TIG welding, a laser welding, or the like) or a solid-phase welding method (a friction agitation joining method), may cause cracks at or approximate to the joined portion W′ when a tensile load is imparted thereto.
Furthermore, in the arm member
51
, since the main body
52
is made of a pipe member in order to lighten the weight of the arm member
51
, thermal fatigue tends to occur at or approximate to the joined portion W′. The thermal fatigue may cause cracks at or approximate to the joined portion W′, resulting in an easy-broken arm member
51
.
SUMMARY OF THE INVENTION
The present invention is made to solve the aforementioned disadvantages of the related art.
An object of the present invention is to provide an arm member which is light in weight and can prevent cracks from causing at or approximate to the joined portion, even though the main body of the arm member used for a suspension arm or an engine mount is made of a pipe member.
Other objects and advantages of the present invention will be apparent from the following preferred embodiments.
In order to attain the aforementioned object, according to the present invention, an arm member includes a main body made of a pipe member having a peripheral wall and a coupling member having a connecting portion. The peripheral wall of the end portion of the main body is formed to have a thickness thicker than that of the other portion of the main body. The connecting portion is abutted to the peripheral wall of the end portion to form an abutted portion, and joined thereto at the abutted portion, whereby the coupling member is coupled to the main body.
In this arm member, since the main body is made of a pipe member, the result is the arm member which is light in weight. Also, since the peripheral wall of the end portion of the main body is formed to have a thickness thicker than that of the other portion of the main body, the mechanical strength of the end portion of the main body is enhanced. Therefore, fracture or breakage at or approximate to the joined portion due to a tensile load or the like imparted thereto can be prevented from occurring. Furthermore, since the peripheral wall of the end portion of the main body is formed to have a thickness thicker than that of the other portion of the main body, thermal fatigue hardly occurs by the joining heat. This also can prevent the end portion of the main body from causing cracks at or approximate to the joined portion. As a result, even though the main body is made of a pipe member, the coupling member is firmly coupled to the main body. In other words, the arm member light in weight and high in joint strength can be provided.
In the aforementioned arm member, it is preferable that the peripheral wall of the end portion of the main body is radially outwardly increased in thickness. This structure simplifies the process of making the thick peripheral wall at the end portion of the main body.
Alternatively, the peripheral wall of the end portion of the main body may be radially inwardly increased in thickness.
It is preferable that a protruded portion integrally formed on the connecting portion is fitted in an opening of the end portion of the main body. This further enhances the mechanical strength of the peripheral wall of the end portion of the main body since the protruded portion fitted in the opening of the end portion of the main body reinforces the peripheral wall of the end portion of the main body from inside of th
Hashimoto Takenori
Kato Rentaro
Kawata Naoyuki
Ogawa Yuichi
Tochigi Masaharu
Kim Harry C.
Tokai Rubber Industries Ltd.
LandOfFree
Arm member does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Arm member, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Arm member will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2577834