U.S. patent application number 12/095151 was filed with the patent office on 2009-06-25 for exhaust pipe structure.
This patent application is currently assigned to TOYOTA JIDOSHA KABUSHIKI KAISHA. Invention is credited to Yoshiki Horie, Junichi Yamaguchi.
Application Number | 20090159147 12/095151 |
Document ID | / |
Family ID | 38561988 |
Filed Date | 2009-06-25 |
United States Patent
Application |
20090159147 |
Kind Code |
A1 |
Yamaguchi; Junichi ; et
al. |
June 25, 2009 |
EXHAUST PIPE STRUCTURE
Abstract
A center of gravity (G1) of a second exhaust pipe (12) is
located on the side of an axis (J1) connecting two associated
support members (16, 17) that is distal to a ball joint (15). Thus,
creating a moment that applies a load (F1) to a ball joint (15 that
presses the ball joint (15) up toward the vehicle body. In turn, by
locating a center of gravity (G2) of a third exhaust pipe (13) on
the side of an axis (J2) connecting two associated support members
(19, 20) that is proximal to the ball joint (15) the weight of the
third exhaust pipe (13) creates a moment which that applies a load
(F2) to the ball joint (15) that presses the ball joint (15) down
away from the vehicle body. Consequently, the load (F1) and the
load (F2) of approximately the same magnitude act in opposite
directions.
Inventors: |
Yamaguchi; Junichi; (
Aichi-ken, JP) ; Horie; Yoshiki; (Aichi-ken,
JP) |
Correspondence
Address: |
SUGHRUE MION, PLLC
2100 PENNSYLVANIA AVENUE, N.W., SUITE 800
WASHINGTON
DC
20037
US
|
Assignee: |
TOYOTA JIDOSHA KABUSHIKI
KAISHA
Toyota-shi
JP
|
Family ID: |
38561988 |
Appl. No.: |
12/095151 |
Filed: |
July 4, 2007 |
PCT Filed: |
July 4, 2007 |
PCT NO: |
PCT/IB2007/001833 |
371 Date: |
May 28, 2008 |
Current U.S.
Class: |
138/155 ;
138/107 |
Current CPC
Class: |
F01N 13/1805 20130101;
F01N 13/0097 20140603; F01N 13/08 20130101; B60K 13/04
20130101 |
Class at
Publication: |
138/155 ;
138/107 |
International
Class: |
F16L 9/22 20060101
F16L009/22 |
Foreign Application Data
Date |
Code |
Application Number |
Jul 10, 2006 |
JP |
2006-189460 |
Claims
1-9. (canceled)
10. An exhaust pipe structure comprising: a plurality of separate
exhaust pipes connected in series as an exhaust pipe connected to
an internal combustion engine; and a universal joint for connecting
the separate exhaust pipes so that the plurality of separate
exhaust pipes bend flexibly at each universal joint, wherein: the
paired separate exhaust pipes are connected to each other through
the universal joint, and each of the paired separate exhaust pipes
is supported in a manner such that a first load applied from a side
of one of the paired separate exhaust pipes to the universal joint
and a second load applied from a side of the other separate exhaust
pipe of the paired separate exhaust pipes to the universal joint,
which are of approximately the same magnitude, act in opposite
directions to each other so that the first load and the second
loads from the weight of the paired separate exhaust pipes, which
act on the universal joint, combine to be almost zero.
11. An exhaust pipe structure comprising: a plurality of separate
exhaust pipes connected in series as an exhaust pipe connected to
an internal combustion engine; and universal joints that connect
the separate exhaust pipes so that the plurality of separate
exhaust pipes bend at the universal joints, wherein: the separate
exhaust pipes include a first exhaust pipe fixedly connected to the
internal combustion engine, a second exhaust pipe connected to the
first exhaust pipe via the first universal joint that is bendable,
and a third exhaust pipe connected to the second exhaust pipe via
the second universal joint that is bendable; each of the separate
exhaust pipes is supported in a manner such that a first load
applied to the second universal joint from the weight of the second
exhaust pipe and a second load applied to the second universal
joint from the weight of the third exhaust pipe, which are of
approximately the same magnitude, act in opposite directions to
each other so that loads from the weight of the separate exhaust
pipes, which act on each of the universal joints, combine to be
almost zero.
12. The exhaust pipe structure according to claim 11, further
comprising: two first support members that support the second
exhaust pipe; and two second support members that support the third
exhaust pipe, wherein the center of gravity of the second exhaust
pipe is located one side of an axis connecting the two first
support members that is proximal to the second universal joint, and
the center of gravity of the third exhaust pipe is located one side
of an axis connecting the two second support members that is distal
to the second universal joint.
13. The exhaust pipe structure according to claim 12, wherein the
third exhaust pipe is supported by one of the two second support
members at a first portion and is supported by the other second
support member at a second portion, the first portion is located at
a position on the third exhaust pipe that is farther from the
second universal joint than the second portion; and the second
portion is located at a position on the third exhaust pipe that is
farthest away from a phantom line connecting the one of the second
support members and the second universal joint.
14. The exhaust pipe structure according to claim 11, further
comprising: two first support members that support the second
exhaust pipe; and two second support members that support the third
exhaust pipe, wherein the center of gravity of the second exhaust
pipe is located one side of an axis connecting the two first
support members that is distal to the second universal joint, and
the center of gravity of the third exhaust pipe is located one side
of an axis connecting the two second support members that is
proximal to the second universal joint.
15. The exhaust pipe structure according to claim 14, wherein the
third exhaust pipe is supported by one of the two second support
members at a first portion and is supported by the other second
support member at a second portion, the first portion is located at
a position on the third exhaust pipe that is farther from the
second universal joint than the second portion; and the second
portion is located at a position on the third exhaust pipe that is
farthest away from a phantom line connecting the one of the second
support members and the second universal joint.
16. The exhaust pipe structure according to claim 11, wherein the
second exhaust pipe is supported at two first support portions; the
third exhaust pipe is supported at two second support portions, the
center of gravity of the second exhaust pipe is located one side of
an axis connecting the two first support portions that is proximal
to the second universal joint, and the center of gravity of the
third exhaust pipe is located one side of an axis connecting the
two second support portions that is distal to the second universal
joint.
17. The exhaust pipe structure according to claim 16, wherein one
of the two second support portions is located at a position on the
third exhaust pipe that is farther from the second universal joint
than the other second support portion, and the other second support
portions is located at a position on the third exhaust pipe that is
farthest away from a phantom line connecting the one of the second
support portions and the second universal joint.
18. The exhaust pipe structure according to claim 11, wherein the
second exhaust pipe is supported at two first support portions; the
third exhaust pipe is supported at two second support portions, the
center of gravity of the second exhaust pipe is located one side of
an axis connecting the two first support portions that is distal to
the second universal joint, and the center of gravity of the third
exhaust pipe is located one side of an axis connecting the two
second support portions that is proximal to the second universal
joint.
19. The exhaust pipe structure according to claim 18, wherein one
of the two second support portions is located at a position on the
third exhaust pipe that is farther from the second universal joint
than the other second support portion, and the other second support
portions is located at a position on the third exhaust pipe that is
farthest away from a phantom line connecting the one of the second
support portions and the second universal joint.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to a structure of an exhaust
pipe connected to an internal combustion engine.
[0003] 2. Description of the Related Art
[0004] Generally, vibrations generated by the internal combustion
engine in operation are transmitted to the exhaust pipe connected
to the internal combustion engine. A load caused by these
vibrations is thus imposed on the exhaust pipe, which
disadvantageously lowers durability and reliability of the exhaust
pipe. In addition, the vibrations are transmitted through a support
member for the exhaust pipe to a vehicle body, causing undesirable
noise and vibrations in the vehicle interior. Therefore, in order
to suppress transmission of exhaust pipe vibrations or absorb the
vibrations, a widely used exhaust pipe structure has: an exhaust
pipe including plural separate exhaust pipes connecting in series
to join an exhaust manifold of the internal combustion engine; and
a universal joint, such as spherical joint, used for connecting the
separate exhaust pipes to allow them to bend flexibly at the joint.
An example of this type of exhaust pipe structure is shown in
Japanese patent application publication JP-A-2002-160536. The
exhaust pipe includes a first exhaust pipe, a second exhaust pipe,
and a tail pipe, the first and second exhaust pipes being joined by
a spherical joint. The exhaust pipe thus formed inhibits
transmission of vibrations from the internal combustion engine to
the exhaust pipe. This improves durability and reliability of the
exhaust pipe, while suppressing undesirable noise or vibrations in
the vehicle interior.
[0005] The aforementioned exhaust pipe structure is designed such
that the exhaust pipe is provided with heavy components, such as a
muffler and a catalytic converter, imposing a load on the universal
joint connecting the separate exhaust pipes. This can cause the
exhaust pipe to be displaced from its normal position in the static
state. When the vehicle travels off-road or over an uneven road
surface, the exhaust pipe, supported at the position out of the
normal mounting position, can be excessively displaced beyond the
allowance range. Thus, the exhaust pipe tends to interfere with
peripheral components. Preferably, the exhaust pipe is supported at
a position adjacent to the universal joint, so that the exhaust
pipe is prevented from being displaced from the normal position.
Nonetheless, supporting the exhaust pipe in this preferred manner
is sometimes difficult mainly due to insufficient body strength at
the position adjacent to the universal joint. As described above,
which part of the exhaust pipe to be supported and where to locate
the universal joint depend on constraints of the vehicle body, such
as body structure. This could result in difficulty in supporting
the exhaust pipe at its normal position in the static state.
SUMMARY OF THE INVENTION
[0006] The present invention provides an exhaust pipe structure,
which ensures that an exhaust pipe is supported at its normal
mounting position.
[0007] A first aspect of the invention is directed to an exhaust
pipe structure having: an exhaust pipe that includes plural
separate exhaust pipes, connected in series to an internal
combustion engine; and a universal joint that connects the separate
exhaust pipes to allow these exhaust pipes to bend flexibly at the
joints. The exhaust pipe structure is designed such that loads from
the weight of the separate exhaust pipes, which act on the
universal joint, combine to be almost zero.
[0008] According to the first aspect, the loads from the weight of
the separate exhaust pipes that act on the universal joint, combine
to be almost zero. Therefore, the universal joint is prevented from
being displaced from its normal position in the static sate,
thereby supporting the exhaust pipe at the normal mounting
position. This prevents the exhaust pipe from being excessively
displaced beyond the allowable range despite vibrations when the
vehicle travels off-road or over an uneven road. Consequently, the
exhaust pipe is precluded from interfering with peripheral
components.
[0009] This also reduces the displacement of the exhaust pipe,
thereby preventing an excessive increase in load on a spring member
that applies a restoring force to the bending universal joint.
Exhaust gas is thus prevented from leaking due to overload on the
spring member.
[0010] The exhaust pipe is supported at its normal position by
controlling the resultant load on the universal joint. This
eliminates the necessity to provide an additional support member
adjacent to the universal joint, for the exhaust pipe. Hence, the
first aspect of the invention gives more flexibility in determining
where to locate the support member for the exhaust pipe and the
universal joint. This facilitates appropriate positioning of the
support member and the universal joint, even if there are some
constraints of a vehicle body structure, such as body strength for
the location of the support member.
[0011] The exhaust pipe may include: a first exhaust pipe connected
to the internal combustion engine in a fixed manner; a second
exhaust pipe connected to the first exhaust pipe via a first
flexible universal joint; and a third exhaust pipe connected to the
second exhaust pipe via a second flexible universal joint. A first
load from weight of the second exhaust pipe and a second load from
weight of the third exhaust pipe, which are of approximately the
same magnitude, may act on the second universal joint in opposite
directions.
[0012] The exhaust pipe thus constructed includes: the first
exhaust pipe connected to the internal combustion engine in a fixed
manner; the second exhaust pipe connected to the first exhaust pipe
via the first flexible universal joint; and the third exhaust pipe
connected to the second exhaust pipe via the second flexible
universal joint. The first load from the weight of the second
exhaust pipe and the second load from the weight of the third
exhaust pipe, which are of approximately the same magnitude, act on
the second universal joint in opposite directions. Thus, almost
zero-load results on the second universal joint. This prevents the
second universal joint from being displaced from its normal
position in the static state, thereby supporting the second exhaust
pipe and the third exhaust pipe connecting in a displaceable manner
at their respective normal mounting positions. The first load from
the weight of the second exhaust pipe and the second load from the
weight of the third exhaust pipe are cancelled out on the second
universal joint. This results in almost zero-load acting on the
first universal joint for connecting the first exhaust pipe and the
second exhaust pipe. A load is thus prevented from being applied to
the first exhaust pipe connected to the internal combustion engine
in a fixed manner, thereby minimizing the adverse effects of the
load on the internal combustion engine and other components.
[0013] The second exhaust pipe and the third exhaust pipe may be
individually supported by two associated support members. A center
of gravity of the second exhaust pipe may be located on the side of
the second universal joint with respect to an axis connecting the
two associated support members for the second exhaust pipe. A
center of gravity of the third exhaust pipe may be located on the
side opposite to the second universal joint with respect to an axis
connecting the two associated support members for the third exhaust
pipe.
[0014] The second exhaust pipe is supported by the two associated
support members, and the center of gravity of the second exhaust
pipe is located on the side of the second universal joint with
respect to the axis connecting the two associated support members.
This results in a load that presses down on the second universal
joint. In turn, the third exhaust pipe is supported by the two
associated support members, and the center of gravity of the third
exhaust pipe is located on the side opposite to the second
universal joint with respect to the axis connecting the two
associated support members. This results in a load that presses up
on the second universal joint. The thus-constructed support members
for the second exhaust pipe and the third exhaust pipe help the
resultant load, acting on the second universal joint, to be almost
zero.
[0015] The second exhaust pipe and the third exhaust pipe may be
individually supported by two associated support members. The
center of gravity of the second exhaust pipe may be located on the
side opposite to the second universal joint with respect to the
axis connecting the two associated support members for the second
exhaust pipe. The center of gravity of the third exhaust pipe may
be located on the side of the second universal joint with respect
to the axis connecting the two associated support members for the
third exhaust pipe.
[0016] The second exhaust pipe is supported by the two associated
support members, and the center of gravity of the second exhaust
pipe is located on the side opposite to the second universal joint
with respect to the axis connecting the two associated support
members. This results in a load that presses up on the second
universal joint. In turn, the third exhaust pipe is supported by
the two associated support members, and the center of gravity of
the third exhaust pipe is located on the side of the second
universal joint with respect to the axis connecting the two
associated support members. This results in a load acting on the
second universal joint to press it down. The thus constructed
support members for the second exhaust pipe and the third exhaust
pipe help the resultant load, acting on the second universal joint,
to be almost zero.
[0017] The third exhaust pipe may be constructed such that one of
the two associated support members supports a part of the third
exhaust pipe further from the second universal joint, while the
other support member supports another part of the third exhaust
pipe furthest from a phantom line connecting the one support member
and the second universal joint.
[0018] The third exhaust pipe is supported by the other support
member at the part furthest from the phantom line, which connects
the one support member and the second universal joint, the one
support member supporting the part of the third exhaust pipe
further from the second universal joint. This minimizes turning
motion of the third exhaust pipe about the phantom line, although
the third exhaust pipe tends to vibrate intensively due to its
location at a free end on the downstream side of exhaust gas flow.
This reduces vibrations of the exhaust pipe when the vehicle
travels off-road or over an uneven road surface, while suppressing
undesirable noise and vibrations in the vehicle interior.
BRIEF DESCRIPTION OF THE DRAWINGS
[0019] The foregoing and further objects, features and advantages
of the invention will become apparent from the following
description of example embodiments with reference to the
accompanying drawings, wherein like numerals are used to represent
like elements and wherein:
[0020] FIG. 1 is a perspective view of an exhaust pipe structure
according to the first embodiment of the invention;
[0021] FIG. 2 is a schematic sectional view of a ball joint;
[0022] FIG. 3 is a schematic perspective view of a support member
for an exhaust pipe;
[0023] FIG. 4 is a schematic diagram of the exhaust pipe structure
when viewed from above a vehicle body;
[0024] FIG. 5 is a schematic diagram of an exhaust pipe structure
according to the second embodiment of the invention;
[0025] FIGS. 6A and 6B are schematic diagrams, illustrating
variations of the exhaust pipe structure; and
[0026] FIGS. 7A, 7B, and 7C are schematic diagrams, illustrating
variations of the exhaust pipe structure.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
[0027] An exhaust pipe structure according to the first embodiment
of the present invention will be described below with reference to
FIGS. 1 to 4.
[0028] FIG. 1 is a perspective view of an exhaust pipe structure 1
according to the first embodiment of the invention. The exhaust
pipe structure 1 includes: a first exhaust pipe 11 connected to an
exhaust manifold 10 of the internal combustion engine; a second
exhaust pipe 12 connected to the first exhaust pipe 11; and a third
exhaust pipe 13 connected to the second exhaust pipe 12. The
exhaust pipes 11, 12, 13 are provided in the lower portion of the
vehicle body, where the internal combustion engine is mounted, in
order of the first exhaust pipe 11, the second exhaust pipe 12, and
the third exhaust pipe 13 from the front to the rear of the vehicle
body. Exhaust gas from the internal combustion engine is discharged
from the exhaust manifold 10 through the first exhaust pipe 11, the
second exhaust pipe 12, and the third exhaust pipe 13 to the
atmosphere.
[0029] The first exhaust pipe 11 is connected to the exhaust
manifold 10 in a fixed manner. The second exhaust pipe 12 is
connected to the first exhaust pipe 11 via a ball joint 14 (first
universal joint). The third exhaust pipe 13 is connected to the
second exhaust pipe 12 via another ball joint 15 (second universal
joint).
[0030] FIG. 2 is a schematic sectional view of the ball joint 14 or
15. The ball joints 14 and 15 are identical in construction. Each
ball joint has a flange 30 fixed to one exhaust pipe A; a flange 31
fixed to the other exhaust pipe B, the exhaust pipes A and B
connected to each other; and a seal member 32 in contact with a
spherical section 31a of the flange 31. The flanges 30 and 31 are
fixed to the associated exhaust pipes by fastening a bolt 33 to
these flanges with a nut 34. A compression coil spring 35 is
disposed between a head 33a of the bolt 33 and the flange 31 to
impel the flanges 30 and 31 toward each other. This allows the
flanges 30 and 31 to hold the seal member 32 with an axial
compression force, ensuring the airtightness of the ball joint. The
spherical section 31a of the flange 31 and the seal member 32 slide
with respect to each other, such that the connecting exhaust pipes
A and B may bend flexibly.
[0031] As described above, in the exhaust pipe structure 1, the
exhaust pipe includes the plural separate exhaust pipes 11, 12, 13,
connected in series, to join the exhaust manifold 10 of the
internal combustion engine. Also, the ball joints 14 and 15 are
used for connecting the separate exhaust pipes 11, 12, 13 to allow
them to bend flexibly at the joints. Thus, the second exhaust pipe
12 and the third exhaust pipe 13 are displaceable relative to the
internal combustion engine. Therefore, vibrations generated by the
internal combustion engine are less likely to be transmitted to the
second exhaust pipe 12 and the third exhaust pipe 13. This improves
durability and reliability of the respective exhaust pipes 11, 12,
13, while suppressing undesirable noise or vibrations in the
vehicle interior.
[0032] The second exhaust pipe 12 is supported by the vehicle body
by two support members 16 and 17. The two support members 16 and 17
are provided on a catalytic converter 18 formed in the second
exhaust pipe 12. In turn, the third exhaust pipe 13 is supported by
the vehicle body by two support members 19 and 20. One of the
support members, denoted as 19, which supports a part of the third
exhaust pipe 13 further from the ball joint 15, is provided on a
muffler 21 formed around the third exhaust pipe 13. The other
support member 20 is provided at a part Y of the third exhaust pipe
13 furthest from a phantom line X connecting the support member 19
and the ball joint 15.
[0033] FIG. 3 is a schematic perspective view of the support
members 16, 17, 19, 20. The support members 16, 17, 19, 20 are
identical in construction and each include a pipe hanger 40, a
vehicle body hanger 41, and a rubber support 42. The pipe hanger 40
extends from the exhaust pipe. The vehicle body hanger 41 extends
from the vehicle body. The rubber support 42 elastically connects
the pipe hanger 40 and the vehicle body hanger 41. The rubber
support 42 is an elastic member that has two through holes 42a and
42b. A distal end 40a of the pipe hanger 40 is inserted through the
through hole 42a. A distal end 41a of the vehicle body hanger 41 is
inserted through the through hole 42b. This allows the exhaust
pipes to be supported by the vehicle body, while reducing
vibrations to be transmitted from the exhaust pipes to the vehicle
body.
[0034] The exhaust pipe structure 1 in a static state will now be
described. FIG. 4 is a schematic diagram of the exhaust pipe
structure 1 when viewed from above a vehicle body 50. A load F1
(first load) and a load F2 (second load) are applied to the ball
joint 15, the load F1 being from the weight of the second exhaust
pipe 12, the load F2 being from the weight of the third exhaust
pipe 13. The center of gravity G1 of the second exhaust pipe 12 is
located on the forward side of the vehicle body 50, in other words,
on the side opposite to the ball joint 15, with respect to the axis
J1 connecting the support members 16 and 17. Thus, the weight of
the second exhaust pipe 12 creates a moment that turns the exhaust
pipe 12 about the axis J1 in the direction of the arrow L1.
Accordingly, the load F1 is applied to the ball joint 15 in a
direction that presses the ball joint 15 up (vertically upward from
the sheet surface of FIG. 4, namely towards the vehicle body).
[0035] In turn, the center of gravity G2 of the third exhaust pipe
13 is located on the forward side of the vehicle body 50 with
respect to an axis J2 connecting the support members 19 and 20, in
other words, on the side of the ball joint 15. Thus, the weight of
the third exhaust pipe 13 creates a moment that turns the exhaust
pipe 13 about the axis J2 in the direction of the arrow L2.
Accordingly, the load F2 is applied to the ball joint 15 in a
direction that presses the ball joint 15 down (vertically downward
from the sheet surface of FIG. 4, namely away from the vehicle
body).
[0036] In the exhaust pipe structure 1, the ball joint 15, the
support members 16 and 17, and the support members 19 and 20 are
positioned such that the load F1 and the load F2 of approximately
the same magnitude act in opposite directions. Therefore, the load
F1 and the load F2, both acting on the ball joint 15, are cancelled
out, so that the second exhaust pipe 12 and the third exhaust pipe
13 are supported at their respective normal mounting positions. As
described above, the load F1 from the weight of the second exhaust
pipe 12 and the load F2 from the weight of the third exhaust pipe
13 are cancelled out at the ball joint 15. This results in almost
zero-load F3 acting on the ball joint 14 that connects the first
exhaust pipe 11 and the second exhaust pipe 12.
[0037] The exhaust pipe structure according to the first embodiment
provides the following effects. (1) A combined load of F1 and F2,
which act on the ball joint 15, is almost zero. The ball joint 15
is thus prevented from being displaced from its normal position in
the exhaust pipe structure 1 in the static state. This allows the
second exhaust pipe 12 and the third exhaust pipe 13 to be
supported at their respective normal mounting positions. Therefore,
the second exhaust pipe 12 and the third exhaust pipe 13 are
prevented from being excessively displaced beyond the allowable
range despite vibrations when the vehicle travels off-road or over
an uneven road surface. This precludes the second exhaust pipe 12
and the third exhaust pipe 13 from interfering with peripheral
components.
[0038] (2) In the exhaust pipe structure 1 in the static state, the
second exhaust pipe 12 and the third exhaust pipe 13 are supported
at their respective normal mounting positions. This reduces the
displacement of the second exhaust pipe 12 and the third exhaust
pipe 13, and therefore, suppresses an excessive increase in force
applied to the compression coil spring 35 of the ball joint 15.
Hence, situations are avoided where an overload is applied to the
compression coil spring 35 beyond its elastic deformation limit,
causing exhaust gas leakage from the ball joint 15.
[0039] (3) The load F1 from the weight of the second exhaust pipe
12 and the load F2 from the weight of the third exhaust pipe 13,
which both act on the ball joint 15, are cancelled out. Thus,
eliminating the need for an additional support member, intended to
reduce the displacement of the ball joint 15, adjacent to the ball
joint 15. Thus, the first embodiment gives more flexibility in
determining where to locate the support members 16 and 17 for the
second exhaust pipe 12, the support members 19 and 20 for the third
exhaust pipe 13, and the ball joints 14 and 15. This facilitates
appropriate positioning of the support members 16, 17, 19, 20, and
the ball joints 14 and 15, even if there are some constraints of
the vehicle body structure, such as body strength for the locations
of the support members 16, 17, 19, 20.
[0040] (4) The load F1 from the weight of the second exhaust pipe
12 and the load F2 from the weight of the third exhaust pipe 13 are
cancelled out on the ball joint 15. This results in almost
zero-load acting on the ball joint 14 in the exhaust pipe structure
1 in the static state. A load is thus prevented from being applied
to the first exhaust pipe 11, which is connected to the internal
combustion engine in a fixed manner, thereby minimizing the adverse
effects of the load on the internal combustion engine and other
components.
[0041] (5) The center of gravity G1 of the second exhaust pipe 12
is located on the side opposite to the ball joint 15 with respect
to the axis J1 connecting the support members 16 and 17. The center
of gravity G2 of the third exhaust pipe 13 is located on the side
of the ball joint 15 with respect to the axis J2 connecting the
support members 19 and 20. The relationship thus established
between the center of gravity G1 and the axis J1 and between the
center of gravity G2 and the axis J2 helps the resultant load,
acting on the ball joint 15, be almost zero.
[0042] (6) The support member 20 for the third exhaust pipe 13 is
provided on the part Y of the third exhaust pipe 13 furthest from
the phantom line X connecting the support member 19 and the ball
joint 15. Therefore, the turning motion of the third exhaust pipe
13 about the phantom line X is minimized, although the third
exhaust pipe 13 tends to vibrate intensively due to its location at
a free end on the downstream side of exhaust gas flow. This reduces
vibrations of the exhaust pipe when the vehicle travels off-road or
over an uneven road surface, while suppressing undesirable noise
and vibrations in the vehicle interior.
[0043] An exhaust pipe structure according to the second embodiment
of the present invention will be described below with reference to
FIG. 5. The overall exhaust pipe structure is designed in the same
manner as in the first embodiment, except for the locations of the
center of gravity of the second exhaust pipe and the third exhaust
pipe. In the following description of the second embodiment,
components common to those described in the first embodiment are
denoted as the same reference numeral, and the descriptions of
these common components are omitted or simplified.
[0044] FIG. 5 is a schematic diagram of an exhaust pipe structure 2
according to the second embodiment, when viewed from above the
vehicle body 50. The center of gravity G3 of the second exhaust
pipe 12 is located towards the rear of the vehicle body 50 with
respect to the axis J1, which connects the support members 16 and
17, in other words, on the side of the ball joint 15. Thus, the
weight of the second exhaust pipe 12 creates a moment that turns
the exhaust pipe 12 about the axis J1 in the direction of the arrow
R1. Accordingly, the load F1 is applied to the ball joint 15 in a
direction that presses the ball joint 15 down (vertically downward
from the sheet surface of FIG. 5, namely away from the vehicle
body).
[0045] In turn, the center of gravity G4 of the third exhaust pipe
13 is located on the rearward side of the vehicle body 50, in other
words, on the side opposite to the ball joint 15, with respect to
the axis J2 connecting the support members 19 and 20. Thus, the
weight of the third exhaust pipe 13 creates a moment that turns the
exhaust pipe 13 about the axis J2 in the direction of the arrow R2.
Accordingly, the load F2 is applied to the ball joint 15 in a
direction that presses the ball joint 15 up (vertically upward from
the sheet surface of FIG. 5, namely towards the vehicle body).
[0046] The ball joint 15, the support members 16 and 17, and the
support members 19 and 20 are positioned such that the load F1 and
the load F2 of approximately the same magnitude act in opposite
directions. Therefore, the load F1 and the load F2, both acting on
the ball joint 15, are cancelled out, so that the second exhaust
pipe 12 and the third exhaust pipe 13 are supported at their
respective normal mounting positions. In addition, almost zero-load
P3 acts on the ball joint 14 connecting the first exhaust pipe 11
and the second exhaust pipe 12.
[0047] The second embodiment provides the following effects in
addition to the effects (1) to (4) achieved by the first
embodiments. (7) The center of gravity G3 of the second exhaust
pipe 12 is located on the side of the ball joint 15 with respect to
the axis J1. The center of gravity G4 of the third exhaust pipe 13
is located on the side opposite to the ball joint 15 with respect
to the axis J2. The relationship thus established between the
center of gravity G3 and the axis J1 and between the center of
gravity G4 and the axis J2 helps the resultant load, acting on the
ball joint 15, be almost zero.
[0048] These above-described embodiments may be modified in the
manner described below.
[0049] According to the first and the second embodiments, the load
F1 and the load F2, which act on the ball joint 15, are cancelled
out. This may apply to various types of exhaust pipe structures of
different forms and arrangements. FIGS. 6A and 6B illustrate an
exhaust pipe structure having a third exhaust pipe 13 of different
form and support members 19 and 20 situated on the rearward side of
the vehicle body 50. FIG. 6A is a schematic diagram of an exhaust
pipe structure 3, in which the center of gravity G5 of the second
exhaust pipe 12 and the center of gravity G6 of the third exhaust
pipe 13 are respectively located on the forward side of the vehicle
body 50 with respect to their associated axes J1 and J2. FIG. 6B is
a schematic diagram of an exhaust pipe structure 4, in which the
center of gravity G7 of the second exhaust pipe 12 and the center
of gravity G8 of the third exhaust pipe 13 are respectively located
on the rearward side of the vehicle body 50 with respect to their
associated axes J1 and J2. The arrangement also allows the load F1
to cancel out the load F2, both of which act on the ball joint
15.
[0050] FIGS. 7A to 7C illustrate variations of the exhaust pipe
structure. FIG. 7A is a schematic diagram of an exhaust pipe
structure 5, in which a center of gravity G9 of the second exhaust
pipe 12 and the ball joint 15 are located on the right side of the
vehicle body 50 with respect to the axis J3. Also, a center of
gravity G10 of the third exhaust pipe 13 is located towards the
rear of the vehicle body 50 with respect to the axis J2. This
arrangement results in a load F1 applied in a vertically downward
direction from the sheet surface of FIG. 7A, as well as a load F2
applied in a vertically upward direction from the sheet surface of
FIG. 7A. Thus, the load F1 cancels out the load F2. FIG. 7B is a
schematic diagram of an exhaust pipe structure 6, in which a center
of gravity G11 of the second exhaust pipe 12 is located on the left
side of the vehicle body 50 with respect to the axis J1. Also, the
ball joint 15 is located on the right side of the vehicle body 50
with respect to the axis J1. Further, a center of gravity G12 of
the third exhaust pipe 13 is located towards the front of the
vehicle body 50 with respect to the axis J2. This arrangement
results in a load F1 applied in a vertically upward direction from
the sheet surface of FIG. 7B, as well as a load F2 applied in a
vertically downward direction from the sheet surface of FIG. 7B.
Thus, the load F1 cancels out the load F2. FIG. 7C is a schematic
diagram of an exhaust pipe structure 7, in which a center of
gravity G13 of the second exhaust pipe 12 and the ball joint 15 are
located on the right side of the vehicle body 50 with respect to
the axis J1. Also, a center of gravity G14 of the third exhaust
pipe 13 is located towards the rear of the vehicle body 50 with
respect to the axis J2. This arrangement results in a load F1
applied in a vertically downward direction from the sheet surface
of FIG. 7C, as well as a load F2 applied in a vertically upward
direction from the sheet surface of FIG. 7C. Thus, the load F1
cancels out the load F2. Although not specifically shown in the
drawing, locating the ball joint 15 on the axis J1 or J2 results in
no load F1 or F2 acting on the ball joint 15. As discussed above,
the present invention may be applied to various types of exhaust
pipe structures of different forms and arrangements.
[0051] According to the first and the second embodiments, the
catalytic converter 18 is formed on the second exhaust pipe 12,
while the muffler 21 is formed on the third exhaust pipe 13.
However, the catalytic converter 18 and the muffler 21 may be
formed on any of the exhaust pipes 11, 12, 13. In addition, the
support members 16, 17, 19, 20 may be provided in any location, as
long as the load F1 and the load F2 cancel each other out.
[0052] According to the first and the second embodiments, the
second exhaust pipe 12 and the third exhaust pipe 13 are
individually supported by the two support members. However,
additional support members may be provided to support each exhaust
pipe.
[0053] According to the first and the second embodiments, the ball
joints 14 and 15 are used to allow the separate exhaust pipes 11,
12, 13 to connect in a bendable manner. However, any other type of
universal joint may be used, for example a flexible bellows
joint.
[0054] According to the first and the second embodiments, the two
ball joints 14 and 15 are used to connect the separate exhaust
pipes to each other. However, three or more ball joints may be used
for connecting the exhaust pipes. In the case of using three or
more ball joints, the loads acting on the respective ball joints,
combine to be almost zero, thereby supporting the exhaust pipe in
its normal position in the static state.
[0055] While the invention has been described with reference to
what are considered to be preferred embodiments thereof, it is to
be understood that the invention is not limited to the disclosed
embodiments or constructions. On the contrary, the invention is
intended to cover various modifications and equivalent
arrangements. In addition, while the various elements of the
disclosed invention are shown in various combinations and
configurations, which are exemplary, other combinations and
configurations, including more, less or only a single element, are
also within scope of the invention.
* * * * *