Casing for receiving electrical connection box

A casing for receiving a plurality of electrical connection boxes, comprising: a casing body for accommodating at least one of the electrical connection boxes in it; a cover for closing an opening of the casing body; and an outer fixing member for fixing the remaining one of the electrical connection boxes to an outside of the casing body, which is provided on the outside of the casing body.

BACKGROUND OF THE INVENTION 
The present invention generally relates to a casing for receiving 
electrical connection boxes such as a junction box, a relay box, a fusible 
link box, etc., which is mounted on a body of a motor vehicle and more 
particularly, to reduction of rise of temperature in the casing due to 
heat produced by the electrical connection boxes accommodated in the 
casing. 
Conventionally, casings for accommodating electrical connection boxes are 
known. FIG. 1 shows one example of the known casings. In FIG. 1, a 
resinous casing body 1 is bolted to a vehicle body (not shown) and an 
upper opening 1a of the casing body 1 is closed by an upper cover 2. A 
bolt 3 is projected into the casing body 1. After the bolt 3 has been 
inserted through a through-hole 4a of a junction box 4, the junction box 4 
is secured to the casing body 1 upon threaded engagement of a nut (not 
shown) with the bolt 3. A relay box 5 and a fusible link box 6 are fixed 
to the junction box 4 by known locking mechanisms (not shown), 
respectively. 
A recess 1c is formed at a portion of a side wall 1b of the casing body 1 
so as to extend up to an upper end of the side wall 1b, while a side 
opening 1d is formed at a lower end portion of the side wall 1b so as to 
open to a bottom of the side wall 1b. Connectors 9A and 9B for connecting 
the relay box 5 to the junction box 4 and connectors 9C and 9D for 
connecting the fusible link box 6 to the junction box 4 are each provided 
at a distal end of a plurality of wires 10 and are inserted into the 
casing body 1 from the recess 1c or the side opening 1d by bundling a 
plurality of the wires 10. 
A packing member (not shown) for hermetically closing the upper opening 1a 
of the casing body 1 is attached to a lower end portion of the upper cover 
2 so as to prevent entry of water into the casing body 1. A grommet 12 is 
fitted around the wires 10 drawn out of the recess 1c so as to prevent 
entry of water into the casing body 1 from the recess 1c. Meanwhile, a 
side cover 13 for closing the side opening 1d is mounted on the side wall 
1b so as to prevent entry of water into the casing body 1 from the side 
opening 1d. 
However, in the above mentioned known casing, such a problem arises that 
since the casing is sealed to some extent for waterproofing, temperature 
in the casing rises by heat produced by circuits of the electrical 
connection boxes upon energization of the circuits. In order to reduce 
rise of temperature in the casing, the number of the circuits of the 
electrical connection boxes accommodated in the casing should be lessened 
or some of the electrical connection boxes should be provided at other 
locations than the casing without being accommodated in the casing. 
Meanwhile, since a number of the electrical connection boxes are 
accommodated in the known casing referred to above, diameters of bundles 
of the wires 10 are large. Therefore, working efficiency for accommodating 
the junction box 4, the relay box 5 and the fusible link box 6 in the 
casing body 1 is not high. Especially, since the fusible relay box 6 is 
provided at the distal end of the wires 10 having large diameter in 
general, working efficiency for accommodating the fusible link box 5 in 
the casing body 1 is low. 
Furthermore, the present invention is also directed to a construction for 
fixing the electrical connection boxes to the casing. FIG. 2 shows one 
example of known constructions for fixing the electrical connection boxes 
to a resinous casing body 21 bolted to a vehicle body (not shown) 
preliminarily in an engine room or the like. Bolts 22A and 22B are 
projected into the casing body 21 and are, respectively, inserted through 
through-holes 23b formed at mounting portions 23a of a junction box 23. 
Then, the junction box 23 is mechanically fixed to the casing body 21 
securely upon threaded engagement of nuts 24A and 24B with the bolts 22A 
and 22B, respectively such that electrical failures of the junction box 23 
is prevented. A fusible link box 26 and relay boxes 27A, 27B and 27C are 
secured to the junction box 23 by known locking mechanisms, respectively. 
Art upper cover 28 and a side cover 29 close an upper opening 21a and a 
side opening 21b of the casing body 21, respectively so as to seal the 
casing body 21 such that waterproofing function is imparted to the casing 
body 21. 
Meanwhile, when the junction box is secured to the vehicle body as 
described above with the bolts and the nuts, tools such as impact wrenches 
for fastening the bolts and the nuts are required to be used and thus, 
operation of fastening the bolts and nuts is troublesome. Meanwhile, when 
the junction box is secured to the vehicle body, cost for the bolts and 
the nuts and cost for fastening the bolts to the casing are incurred, 
thereby resulting in rise of production cost of the motor vehicle. 
Furthermore, in case the above mentioned known construction for fixing the 
electrical connection boxes to the casing is employed, the mounting 
portions 23a having the through-holes 23b are required to be provided in 
the junction box 23 and thus, such an inconvenience is encountered that 
area for laying bus bars (not shown) in the junction box 3 and the number 
of components to be mounted on the junction box 3 are restricted. 
SUMMARY OF THE INVENTION 
Accordingly, a first object of the present invention is to provide, with a 
view to eliminating the above mentioned disadvantages of prior art 
casings, a casing for receiving electrical connection boxes, in which rise 
of temperature due to heat produced by the electrical connection boxes 
accommodated in the casing is reduced and working efficiency for 
accommodating the electrical connection boxes in the casing is raised. 
A second object of the present invention is to provide a construction for 
fixing the electrical connection boxes to the casing, in which the 
electrical connection boxes can be secured to a vehicle body without using 
tools and restrictions on degrees of freedom of configurations of circuits 
in the electrical connection boxes and the number of components to be 
mounted on the electrical connection boxes are lightened. 
In order to accomplish the first object of the present invention, a casing 
for receiving a plurality of electrical connection boxes, according to a 
first embodiment of the present invention comprises: a casing body for 
accommodating at least one of the electrical connection boxes therein; a 
cover for closing an opening of the casing body; and an outer fixing 
member for fixing the remaining one of the electrical connection boxes to 
an outside of the casing body which is provided on the outside of the 
casing body. 
Meanwhile, in order to accomplish the second object of the present 
invention, a construction for fixing an electrical connection box in a 
casing body of a casing, according to a second embodiment of the present 
invention comprises: a plurality of locking members which are provided on 
side faces of a housing of the electrical connection box, respectively and 
each of which includes a locking piece and a guide portion having a guide 
groove; and a plurality of protrusions which are, respectively, provided 
on inner faces of side walls of the casing body so as to be each inserted 
into the guide groove and each of which includes a locking groove 
engageable with the locking piece; wherein one of the locking members acts 
as a reference locking member such that the guide portion of the reference 
locking member is projected further towards the casing body than those of 
the remaining ones of the locking members.

DETAILED DESCRIPTION OF THE INVENTION 
Referring now to the drawings, there is shown in FIGS. 3 to 5, a 
rectangular casing K1 for receiving electrical connection boxes, according 
to a first embodiment of the present invention. As shown in FIG. 3, the 
casing K1 includes a casing body 31 having an upper opening 31a and a 
cover 32 for closing the upper opening 31a. In this embodiment, both the 
casing body 31 and the cover 32 are made of resin. The electrical 
connection boxes accommodated in the casing body 31 include a junction box 
33, relay boxes 37A and 37B and a fusible link box 38. Furthermore, 
connectors 40A, 40B, 40C and 40D are accommodated in the casing K1. The 
junction box 33, the relay boxes 37A and 37B, the fusible link box 38 and 
the connectors 40A to 40D which are accommodated in the casing body 31 are 
provided at distal ends of wires 41. 
The casing body 31 has four side walls 31b, 31c, 31d and 31e, while locking 
bosses 33a, 33b and 33c are provided on the junction box 33. Three 
projections 34 each having a locking groove 34a for its engagement with 
each of the locking bosses 33a to 33c are provided on inner faces of the 
side walls 31b, 31c and 31d, respectively. A support 35 for supporting the 
junction box 33 from below is provided in the vicinity of each of the 
projections 34. 
Likewise, two projections 33e each having a locking groove 33d for its 
engagement with a locking boss (not shown) formed on each of the relay 
boxes 37A and 37B are provided on side faces of the junction box 33. Holes 
42A and 42B for drawing the wires 41 out of the casing body 31 are formed 
on the side walls 31c and 31d. 
A substantially U-shaped frame 44 is provided on an outer face of the side 
wall 31d of the casing body 31 so as to act as an outer fixing member for 
fixing the fusible link box 38 thereto. The frame 44 includes opposite 
side plates 44a and 44b extending substantially perpendicularly to the 
outer face of the side wall 31d and an outer plate 44c for coupling distal 
ends of the side plates 44a and 44b. A mounting through-hole 45 is defined 
by the side wall 31d of the casing body 31, the side plates 44a and 44b 
and the outer plate 44c. A rectangular engageable plate 44d projecting 
into the mounting through-hole 45 is provided at an upper end portion of 
each of the side plates 44a and 44b. 
The cover 32 is formed by a downwardly opening rectangular box and includes 
a closing portion 32a for closing the upper opening 31a of the casing body 
31. A downwardly opening rectangular protective portion 32c for covering 
an upper portion of the fusible link box 38 mounted on the frame 44 of the 
casing body 1 is provided on a side wall 32b of the closing portion 32a. 
The closing portion 32a is further provided with a pair of housing 
portions 32d for receiving upper portions of grommets 47A and 47B, 
respectively. 
Furthermore, as shown in FIG. 4, a slot 32e is formed on a lower end of the 
side wall 32b of the closing portion 32a of the cover 32 so as to receive 
a packing member 48 made of elastic material. When the upper opening 31a 
of the casing body 31 has been closed by the cover 32, an upper end of the 
side walls 31b to 31e is fitted into the slot 32e so as to be brought into 
close contact with the packing member 48. Meanwhile, the cover 32 is 
secured to the upper opening 31a of the casing body 31 by a locking 
mechanism (not shown). 
When the junction box 33, the relay boxes 37A and 37B and the fusible link 
box 38 are accommodated in the casing K1 and are fixed to the casing K1, 
the junction box 33 is initially inserted into the casing body 31 from the 
upper opening 31a and the locking bosses 33a to 33c of the junction box 33 
are brought into engagement with the locking grooves 34a of the 
projections 34 of the casing body 31, respectively such that the junction 
box 33 is secured in the casing body 31. Subsequently, the relay boxes 37A 
and 37B, the fusible link box 38 and connectors 40A to 40D are 
accommodated in the casing body 31. Meanwhile, in this embodiment, the 
wires 41 having the relay box 37A and the connectors 40A and 40B at their 
distal ends are bundled so as to be inserted through the grommet 47A, 
while the wires 41 having the relay box 37B, the fusible relay box 38 and 
the connectors 40C and 40D at their distal ends are bundled so as to be 
inserted through the grommet 47B. 
After the grommet 47A has been attached to the hole 42A of the casing body 
31, the wires 41 for the relay box 37A and the connectors 40A and 40B are 
drawn into the casing body 31 so as to displace the relay box 37A and the 
connectors 40A and 40B into the casing body 31. Then, the relay box 37A is 
secured to the junction box 33 and the connectors 40A and 40B are coupled 
with the junction box 33. 
On the other hand, after the grommet 47B has been attached to the hole 42B 
of the casing body 31, the wires 41 for the relay box 37B and the 
connectors 40C and 40D are drawn into the casing body 31 so as to displace 
the relay box 37B and the connectors 40C and 40D into the casing body 31. 
Then, the relay box 37B is secured to the junction box 33 and the 
connectors 40C and 40D are coupled with the junction box 33. Meanwhile, 
the fusible link box 38 is inserted into the mounting through-hole 45 of 
the frame 44 of the casing body 31 from below in the direction of the 
arrow A in FIG. 3 and then, a locking boss 49a disposed at a distal end of 
each of a pair of locking arms 49 which are provided at opposite ends of 
the fusible link box 38, respectively is brought into engagement with each 
of the engageable plates 44d of the frame 44 of the casing body 31 such 
that the fusible link box 38 is secured to the frame 44. 
In this embodiment, since the fusible link box 38 is secured to outside of 
the casing body 31 as described above, the wires 41 having the fusible 
link box 38 at their distal ends are not required to be drawn into the 
casing body 31. Since the wires 41 having the fusible link box 38 at their 
distal ends are larger in diameter than the wires 41 having the relay 
boxes 37A and 37B or the connectors 40A to 40D at their distal ends and 
therefore, are difficult to handle, working efficiency for accommodating 
the fusible link box 38 in the casing body 31 is raised by eliminating the 
need for drawing the wires 41 for the fusible link box 38 into the casing 
body 31. Meanwhile, since the wires 41 for the fusible link box 38 are not 
required to be drawn into the casing body 31, the number of the wires 41 
to be drawn into the casing body 31 decreases accordingly, thereby 
resulting in rise of working efficiency for accommodating the electrical 
connection boxes in the casing body 31. 
Thereafter, the cover 32 is displaced towards the upper opening 31a of the 
casing body 31 and is mounted on the casing body 31 by the locking 
mechanism (not shown). In this state, the upper end of the side walls 31b 
to 31e of the casing body 31 is brought into close contact with the 
packing member 48, while the upper portions of the grommets 47A and 47B 
are received in the housing portions 32d of the cover 32, respectively. 
Furthermore, the holes 42A and 42B of the casing body 31 are, 
respectively, sealed by the grommets 47A and 47B. Thus, in this 
embodiment, the casing body 31 closed by the cover 32 is sealed to some 
extent by the packing member 48 and the grommets 47A and 47B. Meanwhile, 
when the cover 32 has been mounted on the casing body 31 as described 
above, the protective portion 32c of the cover 31 covers the upper portion 
of the fusible link box 38 mounted on the frame 44 of the casing body 31. 
Thus, in this embodiment, the fusible link box 38 which produces larger 
quantity of heat than the junction box 33 and the relay boxes 37A and 37B 
is attached to outside of the casing body 31. Therefore, although the 
casing body 31 is sealed to some extent by the packing member 48 and the 
grommets 47A and 47B, heat produced by circuits of the fusible link box 38 
upon energization of the circuits is not confined in the casing body 31, 
so that rise of temperature in the casing body 31 is prevented. 
In the casing K1, since the upper portion of the fusible link box 38 
mounted on outside of the casing body 31 is covered by the protective 
portion 32c of the cover 32, it is possible to prevent dust or water from 
penetrating into the fusible link box 38 from above. Meanwhile, the 
present invention is not restricted to the above mentioned first 
embodiment but can be modified variously. For example, in the same manner 
as a prior art casing shown in FIG. 1, the junction box and the relay 
boxes accommodated in the casing body may also be fixed to the casing body 
by bolts and nuts. Furthermore, in this embodiment, the single outer 
fixing member for fixing the fusible link box to the casing body is 
provided but two or more outer fixing members may also be provided. 
In the casing K1 of the present invention, the following effects can be 
gained. Since the outer fixing member for fixing the electrical connection 
box to the casing body is provided on outside of the casing body, rise of 
temperature in the casing body due to heat produced the circuits of the 
electrical connection boxes is reduced in comparison with an arrangement 
in which all the electrical connection boxes are accommodated in the 
casing body. Meanwhile, since the electrical connection box fixed to the 
outer fixing member is not required to be accommodated in the casing body, 
the wires having this electrical connection box at their distal ends are 
not required to be drawn into the casing body and thus, working efficiency 
for accommodating the electrical connection boxes in the casing body 31 is 
raised. 
Meanwhile, when the electrical connection box is inserted into the 
through-hole of the outer fixing member of the casing body, the locking 
arm means provided on the electrical connection box is brought into 
engagement with the engageable plate means of the outer fixing member. As 
a result, the electrical connection box can be fixed to the outer fixing 
member positively. 
Furthermore, since the cover is provided with the protective portion for 
covering the upper portion of the electrical connection box fixed to the 
outer fixing member, it is possible to prevent entry of dust or water into 
the electrical connection box fixed to the outer fixing member. 
The circuits of the fusible link box generally produce larger quantity of 
heat than those of other kinds of the electrical connection boxes such as 
the junction box and the relay box. Therefore, in case the electrical 
connection box fixed to the outer fixing member is the fusible link box, 
rise of temperature in the casing body can be reduced effectively. 
Moreover, since diameter of the wires for the fusible link box is larger 
than those of other kinds of the electrical connection boxes such as the 
junction box and the relay box, working efficiency for accommodating the 
electrical connection boxes in the casing body is improved greatly. 
FIGS. 6 to 15 show a casing K2 for receiving electrical connection boxes, 
according to a second embodiment of the present invention. The second 
embodiment is characterized by a construction for fixing the electrical 
connection boxes to the casing K2. The casing K2 includes a casing body 61 
which is of a rectangular boxlike shape having a bottom. The casing body 
61 is bolted to a vehicle body preliminarily. An upper opening 61a of the 
casing body 61 is closed by an upper cover (not shown) such that the 
casing body 61 is sealed. A junction box 62 and a relay box 63 are 
accommodated in the casing body 61. Wire lead-out portions 61b and 61c for 
drawing out of the casing body 61 wires (not shown) connected to the 
junction box 62 and the relay box 63, respectively are provided on the 
casing body 61. 
The junction box 62 includes a housing 64 having four side faces 64a, 64b, 
64c and 64d. Locking members 65A, 65B and 65C for fixing the junction box 
62 to the casing K2 are, respectively, provided on the side faces 64a, 64b 
and 64c. Among the locking members 65A to 65C in this embodiment, the 
locking member 65A acts as a reference locking member and the remaining 
locking members 65B and 65C act as ordinary locking members. As will be 
described later, the reference locking member 65A is used for positioning 
the junction box 62 in a longitudinal direction X and a lateral direction 
Y, which are orthogonal to a vertical direction Z for mounting the 
junction box 63 on the casing body 61 as shown in FIG. 6. 
The locking members 65A to 65C are of known construction and each include a 
locking piece 66 projecting upwardly like a cantilever. Guide grooves 67A 
and 67B are, respectively, formed on guide portions 69A and 69B which are 
provided at opposite sides of the locking piece 66. A locking projection 
68 is provided at a distal end of the locking piece 66. 
Meanwhile, as shown in FIG. 10, the guide portions 69A and 69B of the 
reference locking member 65A are made longer than those of the ordinary 
locking members 65B and 65C so as to extend further downwardly towards the 
casing body 61 than those of the ordinary locking members 65B and 65C. As 
described below, protrusions 70A, 70B and 70C are provided on the casing 
body 61 so as to be operatively associated with the locking members 65A, 
65B and 65C, respectively and each include a head portion 72. By setting 
length of the guide portions 69A and 69B of the locking members 65A to 65C 
as described above, the head portion 72 of the protrusion 70A is adapted 
to be inserted into the guide grooves 67A and 67B of the reference locking 
member 65A earlier than those of the ordinary locking members 65B and 65C. 
On the other hand, the casing body 61 has four side walls 69a, 69b, 69c and 
69d. The protrusions 70A, 70B and 70C are provided at locations 
corresponding to the locking members 65A, 65B and 65C of the junction box 
62 on an inner face of the side walls 69a, 69b and 69c, respectively so as 
to extend vertically. Each of the protrusions 70A to 70C has a 
substantially T-shaped sectional shape when observed from above and 
includes a neck portion 71 projecting from each of the side walls 69a, 69b 
and 69c and the head portion 72 extending upwardly and laterally outwardly 
in opposite directions from a front face of the neck portion 71. Locking 
grooves 73A, 73B and 73C which are closed at their upper ends 75 are 
formed on the head portions 72 of the protrusions 70A, 70B and 70C, 
respectively. 
The locking members 65A to 65C of the junction box 62 are, respectively, 
brought into engagement with the protrusions 70A to 70C of the casing body 
61 as shown in FIG. 11. Namely, when the head portion 72 of each of the 
protrusions 70A to 70C of the casing body 61 is inserted into the guide 
grooves 67A and 67B of each of the locking members 65A to 65C of the 
junction box 62, the locking piece 66 of each of the locking grooves 65A 
to 65C is elastically deflected rearwards by the head portion 72. Thus, 
the locking projection 68 of the locking piece 66 is rebounded into each 
of the locking grooves 73A to 73C such that an upper face 68a of the 
locking projection 68 and the upper end 75 of each of the locking grooves 
73A to 73C are brought into engagement with each other, while an upper end 
72a of the head portion 72 is brought into contact with an upper end 76 of 
each of the guide grooves 67A and 67B. As a result, since the locking 
members 65A to 65C of the junction box 62 are, respectively, brought into 
engagement with the protrusions 70A to 70C of the casing body 61, the 
junction box 62 is locked to the casing body 61. 
As shown in FIGS. 8 and 9, a distance A1 between the upper face 68a of the 
locking projection 68 and the upper end 76 of each of the guide grooves 
67A and 67B is set to be larger than a distance B1 between the upper end 
75 of each of the locking grooves 73A to 73C and the upper end 72a of the 
head portion 72 by a distance C1. 
Meanwhile, in the reference locking member 65A shown in FIG. 12, a width E1 
of the guide grooves 67A and 67B is set to be larger than a thickness D1 
of the head portion 72 of the protrusion 70A by a distance C2. Like-wise, 
in the ordinary locking members 65B and 65C shown in FIG. 13, a width E1' 
of the guide grooves 67A and 67B is set to be larger than a thickness D1' 
of the head portion 72 of each of the protrusions 70B and 70C by a 
distance C2'. In the reference locking member 65A, the distance C2 in the 
longitudinal direction X is minimized in view of dimensional errors of the 
reference locking member 65A and the protrusion 70A, etc. so as to be 
smaller than the distance C2' of the ordinary locking members 65B and 65C, 
namely, C2&lt;C2'. 
Furthermore, as shown in FIG. 12, a clearance C3 in the lateral direction Y 
is provided between each of opposite side faces of the head portion 72 of 
the protrusion 70A for the reference locking member 65A and an inner side 
face of each of the guide grooves 67A and 67B of the reference locking 
member 65A. Similarly, as shown in FIG. 13, a clearance C3' is provided 
between each of opposite side faces of the head portion 72 of each of the 
protrusions 70B and 70C for the ordinary locking members 65B and 65C and 
an inner side face of each of the guide grooves 67A and 67B of each of the 
ordinary locking members 65B and 65C. The clearance C3 of the reference 
locking member 65A is minimized in view of dimensional errors of the 
reference locking member 65A and the protrusion 70A so as to be smaller 
than the clearance C3 of the ordinary locking members 65B and 65C, namely, 
C3&lt;C3'. 
In the junction box 63, vertically extending base portions 78A, 78B and 78C 
are, respectively, provided adjacent to and below the protrusions 70A, 70B 
and 70C as shown in FIG. 11. An elastic member 80 is bonded to a flat 
upper face 79 of each of the base portions 78A to 78C such that a bottom 
face of the junction box 62 fixed in the casing body 61 is supported by 
the upper face 79 of each of the base portions 78A to 78C through the 
elastic member 80 upon engagement of the locking members 65A to 65C with 
the locking grooves 73A to 73C. 
The elastic member 80 is formed by a rubber sheet having a uniform 
thickness. As shown in FIG. 14, a thickness D of the elastic member 80 is 
set so as to absorb a vertical clearance C between each of the locking 
members 65A to 65C and each of the locking grooves 73A to 73C. Namely, the 
thickness D of the elastic member 80 is set not only to be larger than the 
vertical clearance C but such that compression set of the elastic member 
80 is not produced even if the elastic member 80 is vertically compressed 
through a distance of the vertical clearance C. 
Meanwhile, material of the elastic member 80 is not restricted to rubber 
but may also be sponge. As shown in FIG. 15, the elastic member 80 may be 
replaced by an upwardly convex elastic member 80' which is formed by a 
leaf spring made of metal or resin. Also in this case, a thickness S of 
the elastic member 80' may be set not only to be larger than a vertical 
clearance C between each of the locking members 65A to 65C and each of the 
locking grooves 73A to 73C but such that compression set of the elastic 
member 80' is not produced even if the elastic member 80' is vertically 
compressed through a distance of the vertical clearance C. In case the 
elastic member 80' formed by the leaf spring is employed, L-shaped 
engageable pieces 82A and 82B are, respectively, brought into engagement 
with opposite sides of the elastic member 80' so as to secure the elastic 
member 80' to each of the base portions 78A to 78C. 
The relay box 63 includes a housing 83. Locking members 84A and 84B for 
mounting the relay box 63 on the junction box 62 are provided on a side 
face 83 of the housing 83. Meanwhile, protrusions 86A and 86B having 
locking grooves 85A and 85B are provided at locations corresponding to the 
locking members 84A and 84B of the relay box 63 on the side face 64d of 
the housing 64 of the junction box 62, respectively. Constructions of the 
locking members 84A and 84B of the relay box 63 and the protrusions 86A 
and 86B of the junction box 62 are similar to those of the locking members 
65A to 65C of the junction box 62 and the protrusions 70A to 70C of the 
casing body 61, respectively. In FIG. 6, the junction box 62 and the relay 
box 63 are electrically connected to each other by connection members 87 
and 88 provided on the relay box 63 and the junction box 62, respectively. 
Meanwhile, a base portion 78D for supporting the relay box 63 is provided 
on an inner face of the side wall 69d of the casing body 61 and the 
elastic member 80 is bonded to the upper face 79 of the base portion 78D. 
In this embodiment, when the junction box 62 is fixed to the casing body 
61, the junction box 62 is pushed into the casing body 61 from the upper 
opening 61a. Since the guide portions 69A and 69B of the reference locking 
member 65A are projected further downwardly towards the casing body 61 
than those of the ordinary locking members 65B and 65C as described above, 
the head portion 72 of the protrusion 70A of the casing body 61 is 
initially inserted into the guide grooves 67A and 67B of the reference 
locking member 65A of the junction box 62 and thus, the junction box 62 is 
positioned in the longitudinal direction X and the lateral direction Y 
without play. 
When the junction box 62 is further pushed into the casing body 61, the 
head portions 72 of the protrusions 70B and 70C of the casing body 61 are 
inserted into the guide grooves 67A and 67B of the ordinary locking 
members 65B and 65C of the junction box 62, respectively. Since the 
clearances C2 and C3 of the guide grooves 67A and 67B of the reference 
locking member 65A relative to the protrusion 70A in the longitudinal 
direction X and the lateral direction Y are set to be smaller than the 
clearances C2' and C3' of the guide grooves 67A and 67B of the ordinary 
locking members 65B and 65C relative to the protrusions 70B and 70C as 
described above, the head portions 72 of the protrusions 70B and 70C of 
the casing body 61 can be inserted into the guide grooves 67A and 67B of 
the ordinary locking members 65B and 65C of the junction box 62, 
respectively more smoothly than that of the protrusion 70A. 
Namely, since the casing body 61 is a large resinous molded item, 
positioning of the protrusions 70A to 70C is limited by warpage of the 
casing body 61, contraction of the casing body 61 during its molding, etc. 
However, if the clearances C2 and C2' of the guide grooves 67A and 67B of 
the locking members 65A to 65C relative to the protrusions 70A to 70C in 
the longitudinal direction X and the clearances C3 and C3' of the guide 
grooves 67A and 67B of the locking members 65A to 65C relative to the 
protrusions 70A to 70C in the lateral direction Y are set as described 
above, positioning errors of the protrusions 70A to 70C can be absorbed to 
some extent by the clearances C2' and C3' of the guide grooves 67A and 67B 
of the ordinary locking members 65B and 65C relative to the protrusions 
70B and 70C, which are larger than the clearances C2 and C3 of the guide 
grooves 67A and 67B of the reference locking member 65A relative to the 
protrusion 70A, respectively. As a result, the junction box 62 can be 
smoothly mounted on the casing body 61. 
Subsequently, when the junction box 62 is further pushed into the casing 
body 61, the locking piece 66 of each of the locking members 65A to 65C of 
the junction box 62 is brought contact with the head portion 72 of each of 
the protrusions 70A to 70C of the casing body 61 in response to insertion 
of the head portion 72 of each of the protrusions 70A to 70C into the 
guide grooves 67A and 67B of each of the locking members 65A to 65C so as 
to be elastically deflected. Thus, the locking projection 68 is fitted 
into each of the locking grooves 73A to 73C of the protrusions 70A to 70C. 
As a result, since the locking members 65A to 65C of the junction box 62 
are brought into engagement with the locking grooves 73A to 73C of the 
casing body 61, respectively, the junction box 62 is fixed to the casing 
body 61. 
At this time, the elastic member 80 secured to the upper face 79 of each of 
the base portions 78A to 78C is depressed by a lower face 64e of the 
housing 64 of the junction box 62 so as to be compressed downwardly 
through a distance of the vertical clearance C. Accordingly, the housing 
64 of the junction box 62 is elastically urged upwardly by the compressed 
elastic member 80 such that the upper face 68a of the locking projection 
68 is pressed against the upper end 75 of each of the locking grooves 73A 
to 73C. Therefore, in this embodiment, the clearance C1 in the locking 
grooves 65A to 65C in FIGS. 8 and 9 is absorbed by the elastic member 80 
and thus, vertical play between each of the locking members 65A to 65C of 
the junction box 62 and each of the locking grooves 73A to 73C of the 
casing body 61 is eliminated. 
Thereafter, the locking members 84A and 84B of the relay box 63 are, 
respectively, brought into engagement with the locking grooves 85A and 85B 
of the junction box 62 fixed in the casing body 61. At this time, since a 
lower face 83b of the housing 83 of the relay box 63 is also elastically 
urged upwardly by the elastic member 80 secured to the base portion 78D in 
the same manner as the junction box 62, play between each of the locking 
members 84A and 84B and each of the locking grooves 85A and 85B is 
eliminated. 
In the casing K2 of the present invention, the junction box 62 can be 
easily fixed to the casing body 61 without the need for using tools such 
as an impact wrench by merely bringing the locking members 65A to 65C of 
the junction box 62 into engagement with the locking grooves 73A to 73C of 
the casing body 61, respectively. 
Meanwhile, since the guide portions 69A and 69B of the reference locking 
member 65A of the junction box 62 are projected further downwardly towards 
the casing body 61 than those of the ordinary locking members 65B and 65C, 
the head portion 72 of the protrusion 70A of the casing body 61 is 
initially inserted into the guide grooves 67A and 67B of the reference 
locking member 65A of the junction box 62 and then, the head portions 72 
of the protrusions 70B and 70C of the casing body 61 are inserted into the 
guide grooves 67A and 67B of the ordinary locking members 65B and 65C of 
the junction box 62, respectively. Furthermore, since the clearances C2 
and C3 of the guide grooves 67A and 67B of the reference locking member 
65A relative to the protrusion 70A in the longitudinal direction X and the 
lateral direction Y are set to be smaller than the clearances C2' and C3' 
of the guide grooves 67A and 67B of the ordinary locking members 65B and 
65C relative to the protrusions 70B and 70C, the junction box 62 can be 
smoothly fixed to the casing body 61 even when positioning errors of the 
protrusions 70A to 70C are produced by warpage of the casing body 61, 
contraction of the casing body 61 during its molding, etc. Moreover, since 
the elastic members 80 absorb the vertical clearance C1 of the locking 
members 65A to 65C of the junction box 62, vertical play of the junction 
box 62 in the casing body 61 is eliminated, so that such problems due to 
vibrations of the junction box 62 can be prevented that noises are 
produced, function of components, e.g., relays in the junction box 62 
deteriorates and heat is produced at contact portions between the junction 
box 62 and the casing body 61. 
In addition, the protrusions 70A to 70C provided on the casing body 61 can 
be molded integrally with the casing body 61 at the time of resinous 
molding of the casing body 61, while the locking members 65A to 65C 
provided on the housing 64 of the junction box 62 can be molded integrally 
with the housing 64 of the junction box 62 at the time of resinous molding 
of the housing 64 of the junction box 62. Therefore, since such components 
as bolts 22A and 22B and nuts 24A and 24B employed in a prior art casing 
shown in FIG. 2 are not required to be provided additionally, cost for 
these bolts and nuts and operational cost for fastening the bolts to the 
casing body become unnecessary, thereby resulting in reduction of 
production cost of the casing. 
Furthermore, since mounting portions 23a each having a through-hole 23b 
used in a junction box 23 for the prior art casing of FIG. 2 are not 
required to be provided on the junction box 62 but only the locking 
members 65A to 65C may be provided on the side faces 64a to 64c of the 
housing 64 of the junction box 62, degree of freedom for laying bus bars 
in the junction box 62 is raised and the number of components mounted on 
the junction box 62 can be increased. 
Meanwhile, the present invention is not restricted to the above described 
second embodiment but can be modified variously. For example, in the 
second embodiment, the locking members 65A to 65C are provided on the 
housing 64 of the junction box 62 and the locking grooves 73A to 73C are 
provided on the casing body 61. On the contrary, the locking members may 
also be provided on the casing body 61 by providing the locking grooves on 
the housing 64 of the junction box 62. Meanwhile, the locking mechanism 
for securing the junction box 62 to the casing body 61 is not restricted 
to the locking members 65A to 65C and the locking grooves 73A to 73C but 
may be of any construction. 
Furthermore, in the second embodiment, the junction box 62 is fixed to the 
casing body 61. However, the second embodiment is not restricted to fixing 
of the junction box 62 to the casing body 61 but may also be applicable to 
fixing of other electrical connection boxes such as a relay box and a 
fusible link box to the casing body 61. 
As will be seen from the foregoing description, the following effects can 
be achieved in the casing K2 of the present invention. Firstly, since the 
electrical connection box can be fixed to the casing through mere 
engagement of the locking members of the electrical connection box with 
the locking grooves of the casing body, the electrical connection box can 
be easily fixed to the casing without the need for using tools such as an 
impact wrench. 
Meanwhile, since the locking members and the protrusions can be formed 
integrally with the housing of the electrical connection box and the 
casing body, components such as bolts and nuts for fixing the electrical 
connection box to the casing body are not required to be provided 
additionally, so that cost for the bolts and the nuts and operational cost 
for fastening the bolts to the casing body are obviated, thereby resulting 
in reduction of production cost of the casing. 
Furthermore, since the mounting portions having the through-holes used in 
the electrical connection box for the prior art casing are not required to 
be provided in the electrical connection box, degree of freedom for laying 
bus bars in the electrical connection box is raised and the number of 
components mounted on the electrical connection box can be increased. 
Moreover, since the guide portions of the reference locking member are 
projected further downwardly towards the casing body than those of the 
ordinary locking members, the protrusion corresponding to the reference 
locking member is inserted into the guide grooves of the reference locking 
member earlier than those corresponding to the ordinary locking members 
are inserted into the guide grooves of the ordinary locking members, the 
electrical connection box can be rapidly positioned relative to the casing 
body. 
In addition, since the longitudinal and lateral clearances of the guide 
grooves of the reference locking member relative to the corresponding 
protrusion are set to such minimum values as to enable fitting of the 
corresponding protrusion into the guide grooves of the reference locking 
member to be smaller than those of the ordinary locking members, the 
electrical connection box is positioned relative to the casing body 
without play, while positional errors of the casing body due to warpage of 
the casing body, etc. can be absorbed by the ordinary locking members.