U.S. patent application number 14/335186 was filed with the patent office on 2014-11-06 for method of manufacturing ground connection structure.
This patent application is currently assigned to YAZAKI CORPORATION. The applicant listed for this patent is Yazaki Corporation. Invention is credited to Akira BABA, Hirohito HABARA, Akihiro KOYAMA, Yukinari NAGANISHI, Atsushi NAKATA, Takashi ODAJIMA, Takao OTA, Hideaki SAITOH.
Application Number | 20140325837 14/335186 |
Document ID | / |
Family ID | 48799229 |
Filed Date | 2014-11-06 |
United States Patent
Application |
20140325837 |
Kind Code |
A1 |
NAGANISHI; Yukinari ; et
al. |
November 6, 2014 |
METHOD OF MANUFACTURING GROUND CONNECTION STRUCTURE
Abstract
A ground connection structure is a structure for collectively
connecting, to a body of a vehicle, a plurality of grounding wires
which are connected to respective electrical components installed
in the vehicle. The ground connection structure includes: a
connection box to which the plurality of grounding wires are
connected; a grounding terminal part connected to the vehicle in an
electrically conducting state; and an electrically conducting
connection part having one end connected to the connection box and
the other end connected to the grounding terminal part, the
electrically conducting connection part connecting the connection
box and the grounding terminal part in an electrically conducting
manner. The electrically conducting connection part is made of a
low-inductance material having low inductance.
Inventors: |
NAGANISHI; Yukinari;
(Kosai-shi, JP) ; BABA; Akira; (Kosai-shi, JP)
; ODAJIMA; Takashi; (Kosai-shi, JP) ; HABARA;
Hirohito; (Kosai-shi, JP) ; SAITOH; Hideaki;
(Kosai-shi, JP) ; OTA; Takao; (Kosai-shi, JP)
; KOYAMA; Akihiro; (Kosai-shi, JP) ; NAKATA;
Atsushi; (Makinohara-shi, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Yazaki Corporation |
Tokyo |
|
JP |
|
|
Assignee: |
YAZAKI CORPORATION
Tokyo
JP
|
Family ID: |
48799229 |
Appl. No.: |
14/335186 |
Filed: |
July 18, 2014 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
PCT/JP2013/050718 |
Jan 17, 2013 |
|
|
|
14335186 |
|
|
|
|
Current U.S.
Class: |
29/874 |
Current CPC
Class: |
Y10T 29/49204 20150115;
H01R 43/00 20130101; H01R 4/304 20130101; H01B 5/12 20130101; H01R
11/12 20130101; H01R 2201/26 20130101; Y02T 10/70 20130101; H01R
4/64 20130101; H01R 4/029 20130101; H01R 11/32 20130101 |
Class at
Publication: |
29/874 |
International
Class: |
H01R 43/00 20060101
H01R043/00 |
Foreign Application Data
Date |
Code |
Application Number |
Jan 20, 2012 |
JP |
2012-009739 |
Claims
1. A method of manufacturing a ground connection structure, the
ground connection structure comprising: a connected part to which a
plurality of grounding wires are connected, the grounding wires
being respectively connected to a plurality of electrical
components installed in a vehicle; a grounding terminal part
connected to a body of the vehicle in an electrically conducting
state; and an electrically conducting connection part having one
end connected to the connected part and the other end connected to
the grounding terminal part to connect the connected part and the
grounding terminal part in an electrically conducting manner, the
method comprising: using, as a member constituting the electrically
conducting connection part, a low-inductance material whose
inductance is lower than inductance of a single-core circular wire
whose diameter is established by current capacity based on the
plurality of grounding wires.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application is a Continuation of PCT Application No.
PCT/JP2013/050718, filed on Jan. 17, 2013, and claims the priority
of Japanese Patent Application No. 2012-009739, filed on Jan. 20,
2012, the content of both of which is incorporated herein by
reference.
BACKGROUND
[0002] 1. Technical Field
[0003] The present invention relates to a method of manufacturing a
ground connection structure which connects a plurality of grounding
wires connected to respective electrical components installed in a
vehicle to a body of the vehicle in an electrically conducting
state.
[0004] 2. Related Art
[0005] In electrical components installed in a vehicle, such as an
automobile, hitherto, there are a variety of proposals related to a
ground connection structure by which a plurality of grounding wires
connected to respective electrical components requiring ground
connection are connected to a body of the vehicle in an
electrically conducting state.
[0006] For instance, a ground connection structure is known as a
first conventional example, which connects a plurality of grounding
wires consisting of single-core circular wires to a plurality of
connection points of a body of a vehicle directly. In the ground
connection structure of the first conventional example, the
plurality of connection points have to be formed in the body of the
vehicle in order to connect the plurality of grounding wires to the
body of the vehicle directly.
[0007] Therefore, a ground connection structure is known as the
second conventional example, which connects a plurality of
grounding wires consisting of single-core circular wires to a
busbar in a connection box, so that a single ground terminal
attached to the busbar is connected to a body of a vehicle (refer
to JP H07-249464 A). In the ground connection structure of the
second conventional example, it is possible to reduce the number of
connecting points to be formed in the body of the vehicle since one
ground terminal is connected to the body of the vehicle.
[0008] In the ground connection structure of the second
conventional example, however, it is necessary to wire the
plurality of grounding wires to the connecting box. Thus, the
plurality of grounding wires have to be routed to the vicinity of
the body of the vehicle, so that there is room for improvement with
respect to the routing capability of the grounding wires.
[0009] Therefore, a ground connection structure is known as the
third conventional example, which connects a plurality of grounding
wires, each of which includes a single-core circular wire connected
to respective electrical components, to a connection box (connected
part), and which connects a grounding terminal part, which is
connected to an electrically conducting connection part including a
single-core circular wire for connection drawn out from the
connection box, to a body of a vehicle. In the ground connection
structure of the third conventional example, when the grounding
wires are routed up to the connection box, the conductivity from
the connection box to the body would be accomplished by routing of
the electrically conducting connection part. Thus, it is possible
to improve the routing capability of the electrically conducting
connection part.
SUMMARY
[0010] In the ground connection structure of the third conventional
example, however, the impedance of the electrically conducting
connection part has not been taken account although the routing
capability of the electrically conducting connection part can be
improved. In the ground connection structure of the third
conventional example, that is, the single-core circular wire as the
electrically conducting connection part has a diameter established
by a current capacity based on the number of grounding wires
connected to the connection box, the line thickness of the
grounding wire, etc. Consequently, the noise voltage is elevated
due to the action of a potential drop produced at the electrically
conducting connection part, so that the resulting potential rise
would cause noise.
[0011] Under such a situation, an object of the present invention
is to provide a ground connection structure capable of suppressing
noise derived from a potential rise while ensuring the routing
capability of an electrically conducting connection part, and also
a method of manufacturing the ground connection structure.
[0012] In order to solve the above-mentioned problem, in an aspect
of the present invention, there is provided a method of
manufacturing a ground connection structure, the ground connection
structure including: a connected part to which a plurality of
grounding wires are connected, the grounding wires being
respectively connected to a plurality of electrical components
installed in a vehicle; a grounding terminal part connected to a
body of the vehicle in an electrically conducting state; and an
electrically conducting connection part having one end connected to
the connected part and the other end connected to the grounding
terminal part to connect the connected part and the grounding
terminal part in an electrically conducting manner, the method
including using, as a member constituting the electrically
conducting connection part, a low-inductance material whose
inductance is lower than inductance of a single-core circular wire
whose diameter is established by current capacity based on the
plurality of grounding wires.
[0013] In accordance with the aspect of the present invention, it
is possible to provide the method of manufacturing the ground
connection structure capable of suppressing noise derived from a
potential rise while ensuring the routing capability of the
electrically conducting connection part.
BRIEF DESCRIPTION OF DRAWINGS
[0014] FIG. 1 is a constitutive diagram illustrating electrical
components etc. installed in a vehicle, according to a first
embodiment.
[0015] FIG. 2 is a perspective view illustrating a ground
connection structure according to the first embodiment.
[0016] FIG. 3 is a plan view of the ground connection structure
according to the first embodiment.
[0017] FIG. 4 is a perspective view illustrating a ground
connection structure according to a modification of the first
embodiment.
[0018] FIG. 5 is a plan view illustrating a ground connection
structure according to a second embodiment.
[0019] FIG. 6 is a side view illustrating the ground connection
structure according to the second embodiment.
[0020] FIG. 7(a) is a perspective view illustrating a washer
according to the second embodiment, FIG. 7(b) is a side view
illustrating the washer according to the second embodiment, and
FIG. 7(c) is a plan view illustrating the washer according to the
second embodiment.
[0021] FIG. 8(a) is a perspective view illustrating a connection
fitting according to the second embodiment, and FIG. 8(b) is a
development view illustrating the connection fitting according to
the second embodiment.
[0022] FIG. 9(a) is a plan view illustrating the connection fitting
according to the second embodiment, and FIG. 9(b) is a sectional
view illustrating the connection fitting according to the second
embodiment.
[0023] FIG. 10 is a side view illustrating a ground connection
structure according to a modification of the second embodiment.
[0024] FIG. 11 is a plan view illustrating a ground connection
structure according to a third embodiment.
[0025] FIG. 12 is a side view illustrating the ground connection
structure according to the third embodiment.
[0026] FIG. 13(a) is a perspective view illustrating a washer
according to the third embodiment, FIG. 13(b) is a side view
illustrating the washer according to the third embodiment, and FIG.
13(c) is a plan view illustrating the washer according to the third
embodiment.
[0027] FIG. 14(a) is a plan view illustrating a connection fitting
according to the third embodiment, and FIG. 14(b) is a sectional
view illustrating the connection fitting according to the third
embodiment.
[0028] FIG. 15 is a plan view illustrating a ground connection
structure according to a fourth embodiment.
[0029] FIG. 16 is a side view illustrating the ground connection
structure according to the fourth embodiment.
DETAILED DESCRIPTION
[0030] Ground connection structures according to embodiments of the
present invention will be described with reference to drawings.
[0031] Note, in descriptions of the drawings, identical or similar
elements are indicated with the same or similar reference numerals.
However, it should be noted that the drawings are only exemplary,
and ratios etc. among respective dimensions are different from
actual ratios respectively.
[0032] Accordingly, detailed dimensions etc. should be judged in
consideration of the descriptions. Additionally, different
dimensional relationships or ratios between elements may be
included throughout the drawings.
(1) First Embodiment
[0033] A ground connection structure according to a first
embodiment will be described with reference to the drawings.
(1.1) Schematic Constitution of Vehicle
[0034] The schematic constitution of a vehicle 1 using the ground
connection structure 100 according to the first embodiment will be
described with reference to FIG. 1. It is supposed that the vehicle
1 is an automobile (including an electric car, a hybrid electric
car, or the like).
[0035] A plurality of electrical components 10A-10H are installed
in the vehicle 1. A plurality of grounding wires 20A-20H each
including a single core circular wire formed by a core and a
covering material are connected to the electrical components
10A-10H, respectively. The plurality of grounding wires 20A-20H are
grounded to a body BD of the vehicle 1 by the ground connection
structure 100 according to the first embodiment.
[0036] Concretely, the plurality of grounding wires 20A-20D
connected to the electrical components 10A-10D respectively are
collected up into a connection box 110A, while the plurality of
grounding wires 20E-20H connected to the electrical components
10E-10H respectively are collected up into a connection box 110B.
Then, grounding terminal parts 120 connected to electrically
conducting connection parts 130 drawn out from the respective
connection boxes 110A, 110B are connected to the body BD of the
vehicle 1. In this way, the plurality of electrical components
10A-10H are grounded to the body BD of the vehicle 1.
[0037] As the electrical components 10A-10H, the grounding wires
20A-20H, and the connection boxes 110A, 110B are respectively
constructed similarly to each other, the electrical components
10A-10H will be simply referred to as "electrical component 10",
the grounding wires 20A-20H will be simply referred to as
"grounding wire 20", and the connection boxes 110A, 110B will be
referred to as "connection box 110" hereinafter.
(1.2) Constitution of Ground Connection Structure
[0038] The constitution of the ground connection structure 100
according to the first embodiment will be described with reference
to FIGS. 2(a), 2(b), and 3.
[0039] The ground connection structure 100 is directed to connect
the plurality of grounding wires 20, which are respectively
connected to the plurality of electrical components 10 installed in
the vehicle 1, to the body BD of the vehicle 1. The ground
connection structure 100 includes the connection box 110 (connected
part) to which the plurality of grounding wires 20 are connected
respectively, the grounding terminal part 120 connected to the body
BD of the vehicle 1 in an electrically conducting state and the
electrically conducting connection part 130 connecting the
connection box 110, and the grounding terminal part 120 in an
electrically conducting manner.
[0040] The connection box 110 connects the grounding wires 20 and
the electrically conducting connection part 130 in an electrically
conducting state. One ends 21 of the respective grounding wires 20
and one end 131 of the electrically conducting connection part 130
arc fixed to the connection box 110 by pressure bonding, welding,
or the like.
[0041] The one ends 21 of the respective grounding wires 20 and the
one end 131 of the electrically conducting connection part 130 need
not necessarily be fixed to the connection box 110 by means of
pressure bonding or welding, the grounding wires 20 have only to be
connected to the electrically conducting connection part 130 in an
electrically conducting state.
[0042] The grounding terminal part 120 is connected to the other
end 132 of the electrically conducting connection part 130. The
grounding terminal part 120 is formed with a circular
bolt-insertion hole 121 into which a bolt B (fixing member) used
for fixture with the body BD is inserted. The grounding terminal
part 120 has only to be connected to the body BD in an electrically
conducting state and may be appropriately modified in terms of its
size, configuration, and so on.
[0043] The bolt B has electrical conductivity and fixes the
grounding terminal part 120 to the body BD together with a nut N
welded securely to the body BD. As illustrated in FIG. 2(b), the
bolt B includes a bolt part BB threadedly engaged with the nut N,
and a disc-shaped flange BF for pressing the grounding terminal
part 120 onto the side of the body BD. The bolt part BB is formed
with a recess part B1 for shaving off a coating (cation coating) of
the body BD, an external facing in the nut N, such as
anticorrosive.
[0044] The electrically conducting connection part 130 is provided
between the connection box 110 and the grounding terminal part 120.
One end 131 of the electrically conducting connection part 130 is
connected to the connection box 110 in an electrically conducting
state. The other end 132 of the electrically conducting connection
part 130 is connected to the grounding terminal part 120 in an
electrically conducting state.
[0045] The electrically conducting connection part 130 is formed by
a low-inductance material 130A having low inductance. In the first
embodiment, there is used, as a member constituting the
electrically conducting connection part 130, a low-inductance
material 130A whose inductance is lower than inductance of a
single-core circular wire whose diameter is established by current
capacity based on the plurality of grounding wires 20. That is, the
low-inductance material 130A has inductance lower than that of the
electrically conducting connection part (single-core circular wire
whose diameter is established by current capacity) described in
Background Art.
[0046] In detail, the low-inductance material 130A is formed by a
flat braided wire having flexibility. In the low-inductance
material 130A, its cross section perpendicular to an extending
direction of the low-inductance material 130A is flat-shaped
(including elliptical and rectangular shapes). The low-inductance
material 130A may be formed by a flat-shaped conductor in cross
section perpendicular to its extending direction, such as
flat-shaped wire and busbar, without being limited to the flat
braided wire.
(1.3) Comparative Evaluation
[0047] The comparative evaluation in case of using the
low-inductance material 130A and a known single-core circular wire
for the electrically conducting connection part 130 will be
described with reference to Table 1.
[0048] The low-inductance material 130A according to the first
embodiment is formed by a flat braided wire. The low-inductance
material 130A is flat-shaped in cross section perpendicular to the
extending direction of the low-inductance material 130A. While, the
single-core circular wire is formed by a core line and a covering
material. The single-core circular wire is circular in cross
section perpendicular to its extending direction.
TABLE-US-00001 TABLE 1 inductance L [nH] impedance Z [.OMEGA.] line
length (measured value (measured value) [mm] @ 0.1 MHz) @ 0.1 MHz @
1 MHz @ 10 MHz single-core circular wire 235 145 0.09 0.91 9.11
(5.5 sq.) flat braided wire 235 97 0.06 0.61 6.09 (1.1(t) .times.
12(w) mm)
[0049] When representing the frequency of alternating current by f
and the inductance of the electrically conducting connection part
130 by L, then the impedance Z of the electrically conducting
connection part 130 is represented by an equation Z=2.pi.f L. As
illustrated in Table 1, when comparing the low-inductance material
130 A (flat braided wire) with the single-core circular wire, it is
appreciated that the inductance L gets smaller from 145 nH to 9 7
nH. Consequently, the impedance Z falls from 0.09.OMEGA. to
0.06.OMEGA. at frequency of 0.1 MHz, from 0.91.OMEGA. to
0.61.OMEGA. at frequency of 1 MHz, and from 9.11.OMEGA. to
6.09.OMEGA. at frequency of 10 MHz. That is, the low-inductance
material 130A can reduce its impedance by approximately 2/3 in
comparison with the single-core circular wire.
(1.4) Operation and Effects
[0050] In the first embodiment, the electrically conducting
connection part 130 is formed by the low-inductance material 130A
having low inductance, namely, the low-inductance material 130A
whose inductance is lower than that of the electrically conducting
connection part (single-core circular wire whose diameter is
established by current capacity) described in Background Art. Thus,
as the impedance can be reduced by the low-inductance material
130A, it is especially possible to realize low impedance against
high-frequency AC component. As the low-impedance electrically
conducting connection part 130 reduces significantly possibility of
potential drop, it is possible to suppress a rising of noise
voltage caused by such potential drop, allowing a prevention of
noise resulting from such potential rise. As a result, it is
possible to prevent noise from having adverse impacts on electrical
components installed in a vehicle (i.e. causing the components to
be operated unstably or non-functionally).
[0051] In the first embodiment, the electrically conducting
connection part 130 is provided to connect the connection box 110
and the electrically conducting connection part 130 in an
electrically conducting manner. Consequently, when only the
grounding wires 20 are routed up to the connection box 110, the
electrical conductivity from the connection box 110 to the body BD
would be accomplished by routing of the electrically conducting
connection part 130 only. Thus, it is possible to ensure the
routing capability of the electrically conducting connection part
130.
[0052] In the first embodiment, the low-inductance material 130A is
flat-shaped in cross section. In the low-inductance material 130A,
accordingly, it is possible to make its impedance small in
comparison with a single-core circular wire which is
circular-shaped in cross section. For this reason, it is
particularly possible to realize the low-impedance electrically
conducting connection part 130 for high-frequency AC component.
[0053] In the first embodiment, the low-inductance material 130A is
formed by a flat braided wire. Consequently, due to its superior
flexibility, it is possible to improve the routing capability of
the electrically conducting connection part 130.
(1.5) Modification
[0054] A modification of the ground connection structure 100
according to the first embodiment will be described with reference
to FIG. 4. Note, elements identical to those of the ground
connection structure 100 according to the first embodiment are
respectively indicated with the same reference numerals, and the
following description is mainly directed against different
parts.
[0055] In the ground connection structure 100 according to the
first embodiment, the electrically conducting connection part 130
consists of only the low-inductance material 130A. In contrast, in
a ground connection structure 100A according to the modification,
the electrically conducting connection part 130 consists of a
low-inductance material 130A and a covering member 130B covering
the low-inductance material 130A. For the covering member 130B,
there may be used, for example, heat shrinkable tube, light cure
resin or the like. Alternatively, the covering member 130B may be
provided by die molding of resin, such as vinyl-chloride,
elastomer, ethylene-propylene rubber (EPDM), or the like.
[0056] Thus, in the electrically conducting connection part 130 of
the ground connection structure 100A according to the modification,
the low-inductance material 130A is covered with the covering
member 130B. Consequently, the low-inductance material 130A can be
protected from its deterioration and it is possible to prevent the
deterioration of the low-inductance material 130A. For this reason,
it is possible to improve the durability the low-inductance
material 130A. Also, the covering member 130E has the function of
holding the configuration of the low-inductance material 130A in a
flat shape.
(2) Second Embodiment
[0057] A ground connection structure according to a second
embodiment will be described with reference to drawings. Note,
elements identical to those of the ground connection structure 100
according to the first embodiment are respectively indicated with
the same reference numerals, and the following description is
mainly directed against different parts.
(2.1) Constitution of Ground Connection Structure
[0058] The constitution of the ground connection structure 100A
according to the second embodiment will be described with reference
to FIGS. 5 to 9.
[0059] As illustrated in FIGS. 5 and 6, the ground connection
structure 100A further includes a disc-shaped washer 140 (first
fastened member) arranged between the grounding terminal part 120
and the body BD of the vehicle 1. Although the second embodiment
will be described on the assumption that the washer 140 is made of
iron material, it may be made of other metallic materials, such as
copper and aluminum, without being limited to iron material.
[0060] As illustrated in FIGS. 7(a) to 7(c), the washer 140 is
formed with a circular bolt-insertion hole 141 into which the bolt
B is inserted. The washer 140 has a plurality of (six in the
figure) projections 142 projecting toward the side of the body BD.
That is, the projections 142 are formed on a washer's surface where
the washer 140 butts against the body BD.
[0061] The projections 142 are provided independently of the washer
140. In detail, each of the projections 131 includes a base 142A
fixed to a groove part 143 of the washer 140 and a tip part 142B
formed in succession to the base 142A so as to face toward a tip
sharply (conically). A clearance 144 is defined between the tip
part 142B and the groove part 143 of the washer 140.
[0062] When the washer 140 is tightened by the bolt B and the nut
N, the projections 142 come into contact with the body BD while
shaving off an external facing E of the body BD (shown with thick
line of FIG. 6) such as coating (cation coating) and anticorrosive.
The so-shaved external facing E of the body BD enters the
clearances 144. For this reason, the conductivity between the
washer 140 and the body BD can be ensured. Preferably, the washer
140 is subjected to quenching after forming the projections 142 in
order to increase its hardness.
[0063] The ground connection structure 100A includes, in place of
the connection box 110 described in the first embodiment, a
connection fitting 150 (connected part) allowing the plurality of
grounding wires 20 to be connected to the electrically conducting
connection part 130 in an electrically conducting state.
[0064] As illustrated in FIGS. 8 and 9, the connection fitting 150
connects the plurality of grounding wires 20 and the electrically
conducting connection part 130 in an electrically conducting state.
The connection fitting 150 is formed by folding a long plate
(metallic material) along a folding center line WL.
[0065] The connection fitting 150 is formed with wire connection
grooves 151 for connection with the plurality of grounding wires 20
and a connection-part connection groove 152 for connection with the
electrically conducting connection part 130.
[0066] The grounding wires 20 are positioned since respective one
ends 21 of the grounding wires 20 are inserted into the respective
wire connection grooves 151. The electrically conducting connection
part 130 is positioned since one end 131 of the electrically
conducting connection part 130 is inserted into the connection-part
connection groove 152. Then, as illustrated in FIGS. 9(a) and 9(b),
the one ends 21 of the grounding wire 20 are fixed to the wire
connection grooves 151 by resistance welding S. Similarly, the one
end 131 of the electrically conducting connection part 130 is fixed
to the connection-part connection groove 152 by resistance welding
S.
[0067] Note, resistance welding S means a technique of connecting
an object to be welded (the grounding wires 20 and the electrically
conducting connection part 130) to another element by pressurizing
the object at the same time of melting the object with use of Joule
heat generated by applying electrical current to the object.
[0068] In the second embodiment, the other end 132 of the
electrically conducting connection part 130 is also fixed to the
grounding terminal part 120 by resistance welding S (see FIG. 5).
Also, the nut N is fixed to the body BD by resistance welding S
(see FIG. 6). That is, respective connection parts in the ground
connection structure 100A are all secured with use of resistance
welding S.
(2.2) Operation and Effects
[0069] In the second embodiment, the washer 140 includes the
projections 142 projecting toward the side of the body BD. As the
projections 142 shave off the external facing E of the body BD such
as coating (cation coating) and anticorrosive, the conductivity
between the washer 140 and the body BD is improved. Comparing with
a case that the external facing E of the body BD is not shaved off,
therefore, the electrical resistance between the washer 140 and a
base metal of the body BD (around the bolt B) becomes reduced and
particularly, the electrical resistance against alternating current
component becomes lower. Thus, it is possible to prevent noise
voltage from being elevated by the action of a potential drop
caused around the bolt B and also possible to suppress noise
derived from a potential rise.
[0070] For instance, in case of using the low-inductance material
130A having 20 mm in width, 200 mm in length and 14 mm.sup.2 in
cross-section area, the result was that the electrical resistance
of the low-inductance material 130A was 0.33 m.OMEGA., while the
electrical resistance between the washer 140 and the body BD was
approximately 0.4-0.6 m.OMEGA.. That is, as the electrical
resistance around the bolt B is reduced to about 0.5 m.OMEGA., the
potential of the bolt B can be approximated to the potential of the
body BD. Therefore, it is possible to suppress noise derived from a
potential rise.
[0071] In the second embodiment, each connection part in the ground
connection structure 100A allowing the passage of current is
secured by resistance welding S. Consequently, the potential
difference among respective connection parts in the ground
connection structure 100A allowing the passage of current is
reduced to enable current interference from the grounding wires 20
up to the electrically conducting connection part 130 to be
reduced. For this reason, it is possible to establish a potential
equalization between the connection fitting 150 and the body BD,
effecting similar grounding performance as the case of directly
connecting the plurality of grounding wires to the body BD like the
ground connection structure in the first conventional example
described in Background Art.
(2.3) Modification
[0072] A modification of the ground connection structure 100A
according to the second embodiment will be described with reference
to FIG. 10. Note, elements identical to those of the ground
connection structure 100A according to the second embodiment are
respectively indicated with the same reference numerals, and the
following description is mainly directed against different
parts.
[0073] In the second embodiment, the washer 140 is arranged between
the grounding terminal part 120 and the body BD of the vehicle 1.
In contrast, the ground connection structure 100A according to the
modification further includes a disc-shaped washer 160 arranged
between the bolt B (fixing member) and the grounding terminal part
120, in addition to the washer 140 described in the second
embodiment. The constitution of the washer 160 is similar to that
of the washer 140.
[0074] In addition to the operation and effect of the second
embodiment, the conductivity between the washer 160 and the
grounding terminal part 120 can be ensured in the modification to
enable the grounding terminal part 120 to be grounded to the body
certainly.
(3) Third Embodiment
[0075] A ground connection structure according to a third
embodiment will be described with reference to drawings. Note,
elements identical to those of the ground connection structures 100
and 100A according to the first and second embodiments mentioned
above are respectively indicated with the same reference numerals,
and the following description is mainly directed against different
parts.
(3.1) Constitution of Ground Connection Structure
[0076] The constitution of a ground connection structure 100B
according to the third embodiment will be described with reference
to FIGS. 11 to 14.
[0077] As illustrated in FIGS. 11 and 12, the ground connection
structure 100B includes the washers 140, 160 described in the
second embodiment.
[0078] As illustrated in FIG. 13, the washer 140 is provided, on
its outer periphery, with a waterproof packing 140A (first
waterproof member) for preventing an invasion of liquid pointing
toward the inner circumferential side of the washer 140 (i.e. side
of the bolt insertion hole 141 or the projections 142). The
waterproof packing 140A is made of silicone rubber or the like.
[0079] The constitution of the washer 160 is also similar to that
of the washer 140. That is, as illustrated in FIG. 12, the washer
160 is also provided, on its outer periphery, with a waterproof
packing 160A (second waterproof member) for preventing an invasion
of liquid pointing toward the inner circumferential side of the
washer 160.
[0080] In the ground connection structure 100B, the connection
fitting 150 is covered with a sealant 170 made of resin. In detail,
as illustrated in FIGS. 11, 12 and 14, the vicinity of the
connection fitting 150 is covered with the sealant 170 under
condition that the grounding wires 20 are fixed to the wire
connection grooves 151 by the resistance welding S and the
electrically conducting connection part 130 is fixed to the
connection-part connection groove 152 by the resistance welding
S.
(3.2) Operation and Effects
[0081] In the third embodiment, the washer 140 is provided with the
waterproof packing 140A. Consequently, there is no possibility that
liquid, such as water, invades the inner circumferential side of
the washer 140, and it is possible to prevent liquid from adhering
to the washer's parts where the external facing E of the body BD
such as coating (cation coating) and anticorrosive have been shaved
off by the projections 142. For this reason, it is possible to
improve the durability of the external facing E of the body BD.
[0082] In the third embodiment, the washer 160 is provided with the
waterproof packing 160A. Consequently, there is no possibility that
liquid, such as water, invades the inner circumferential side of
the washer 160, and it is possible to prevent liquid from adhering
to its portions in contact with the bolt B and the grounding
terminal part 120. Therefore, it is possible to suppress the
occurrence of electric corrosion (ion-oxidation) despite the
occurrence of a potential difference at the bolt B or the grounding
terminal part 120. As a result, there is less possibility of a
loose bolt B or a lifted pole due to corrosion, so that the bolt B
can be prevented from dropping out. Additionally, there is no
possibility of aged deterioration about the bolt B since it is not
corroded and therefore, it is possible to realize the potential
equalization between the electrically conducting connection part
130 and the body BD.
[0083] In the third embodiment, the connection fitting 150 is
covered with the sealant 170. Thus, it is possible to prevent
liquid from invading not only the inside of the connection fitting
150 but also the inside of the grounding wires 20 (i.e. core lines
inside the covering material), allowing a suppression of the
occurrence of electric corrosion (ion-oxidation) inside the
connection fitting 150 and the grounding wires 20.
[0084] The third embodiment has been described on the assumption
that the ground connection structure 100B includes the washers 140,
160. It is not limited to this but the same structure may include
only the washer 140. Additionally, the connection fitting 150 does
not always have to be covered with the sealant 170.
(4) Fourth Embodiment
[0085] A ground connection structure according to a fourth
embodiment will be described with reference to drawings. Note,
elements identical to those of the ground connection structures
100, 100A, 100B according to the first, second and third
embodiments mentioned above are respectively indicated with the
same reference numerals, and the following description is mainly
directed against different parts.
(4.1) Constitution of Ground Connection Structure
[0086] The constitution of the ground connection structure 100C
according to the fourth embodiment will be described with reference
to FIGS. 15 and 16.
[0087] The ground connection structure 100C includes at least one
ferrite 180 (magnetic material) attached to at least one of the
plurality of grounding wires 20 (e.g. an uppermost grounding wire
20 in FIG. 15).
[0088] The ferrite 180 can absorb high-frequency noise. The ferrite
180 is attached to the side of one end 21 of one of the grounding
wires 20 to be regarded as a noise generation source in the
grounding wires 20. Note, the wire 20 to be regarded as the noise
generation source corresponds to a wire generating the largest
high-frequency noise, a wire that is the most frequent in the
occurrence of noise, a wire connected to an electrical component 10
operated at the highest voltage, and so on.
The fourth embodiment has been described on the assumption that the
ferrite 180 is attached to only the grounding wire 20 regarded as
the noise generation source. It is not limited to this but the
ferrite 180 may be attached to all of the grounding wires 20.
[0089] The ground connection structure 100C further includes a
casing 190 made of resin and enclosing the plurality of grounding
wires 20, the connection fitting 150, and the ferrite 180. Note,
the ground connection structure 100C does not always have to
include the casing 190 and therefore, the former may be provided
with no casing.
(4.2) Operation and Effects
[0090] In the fourth embodiment, the ground connection structure
100C includes the ferrite 180 as magnetic material attached to the
grounding wire 20 regarded as the noise generation source in the
plurality of grounding wires 20. Consequently, it is possible to
prevent high-frequency current from entering the connection fitting
150 and also possible to suppress a potential difference in the
connection fitting 150. For this reason, it is possible to suppress
a potential rise in the connection fitting 150 and make its
potential closer to the potential of the body BD (that is, an
establishment of the potential equalization between the connection
fitting 150 and the body BD). Thus, the noise derived from a
potential rise can be suppressed.
[0091] In the fourth embodiment, the casing 190 encloses the
plurality of grounding wires 20, the connecting fitting 150, and
the ferrite 180. Consequently, it becomes easy to prevent liquid
from invading not only the insides of the connection fitting 150
and the ferrite 180 but also the inside of the grounding wires 20
(i.e. core lines inside the covering material), allowing a
suppression of the occurrence of electric corrosion (ion-oxidation)
inside the connection fitting 150, the ferrite 180 and the
grounding wires 20.
(5) Other Embodiments
[0092] Although the content of the invention has been disclosed
through the embodiments as mentioned above, it should not be
understood that the invention is limited by the descriptions and
the drawing forming the invention in part. From this disclosure,
various alternatives, embodiments and operation techniques will be
obvious to those skilled in the art.
[0093] For instance, the connected part has been described in the
form of the connection box 110 or the connection fitting 150. It is
not limited to these representatives but the connected part has
only to be constructed so as to hold the plurality of grounding
wires 20 collectively.
[0094] Further, as the grounding terminal part 120, it has only to
be connected to the body BD in an electrically conducting state
and, of course, it may be formed with any constitution and profile
besides the constitutions and profiles described in the respective
embodiments. Additionally, the embodiments have been described on
the assumption that means for fixing the grounding terminal part
120 to the body BD includes the bolt B and the nut N. It is not
limited to this combination but it may be replaced with another
element capable of fixing the grounding terminal part 120 to the
body BD in an electrically conducting state.
[0095] Still, the electrically conducting connection part 130 (the
low-inductance material 130A) according to the respective
embodiments can be advantageously used as, for example, a
battery-ground wire for connecting a negative terminal of a battery
installed in a vehicle to the body of the vehicle. If adopting the
electrically conducting connection part 130 for a battery-ground
wire, it is preferable that the low-inductance material 130A is
covered with the covering member 130B and also preferable that a
terminal like the grounding terminal part 120 is connected to the
one end 131 of the electrically conducting connection part 130.
[0096] Note, it is a matter of course that different constitutions
described in the first to fourth embodiments may be combined to
provide the ground connection structure of the present
invention.
[0097] Thus, it is a matter of course that the present invention
may encompass various embodiments which are not described herein.
Accordingly, the technical scope of the present invention is
defined by only all matters specifying the invention, which are
related to reasonable claims from the above explanations.
* * * * *