Information
-
Patent Grant
-
6369682
-
Patent Number
6,369,682
-
Date Filed
Wednesday, September 27, 200023 years ago
-
Date Issued
Tuesday, April 9, 200222 years ago
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Inventors
-
Original Assignees
-
Examiners
Agents
-
CPC
-
US Classifications
Field of Search
US
- 335 282
- 336 192
- 336 198
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International Classifications
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Abstract
A bobbin has a simple and precise means for locating and securing terminals onto the bobbin for use in a fuel injector. The bobbin has open terminal posts and flange holding notches for locating the terminals on the bobbin, and a flange locking notch for securing the terminals within the framework of the bobbin after connecting a wire and rotating.
Description
TECHNICAL FIELD
The present invention relates generally to a fuel injector. More specifically, the present invention relates to the coil assembly for a fuel injector of an internal combustion engine.
BACKGROUND OF THE INVENTION
Fuel injectors are generally defined as an electromagnetic valve mechanism that sprays fuel into the intake system of an internal combustion engine.
Proper control of the moving portion of a fuel injector improves fuel spray quality while limiting flow rate variation. This moving portion, or guiding valve, opens and closes to allow fuel to pass uniformly through an opening of the injector valve seat. In a fuel injector, the controlling of the guiding valve is based on the generation of energy via a coil assembly.
The coil assembly is a multi-functional device that provides structure to wind wires, structure to support electrical interface elements, structure to capture interface terminals during insertion and termination, and is the energy source that is utilized to generate a magnetic field to open the injector valve.
The coil assembly is comprised of five major pieces. These pieces are a bobbin, two terminals, wire, and a bobbin clip. The terminals are attached to the bobbin through the two terminal posts located on a portion of the bobbin. The wire is wrapped around the winding bay of the bobbin and each end of the wire is wrapped around a portion of a different terminal and secured to the terminal typically by soldering. The portion of the terminals containing the wire is then secured within the framework of the bobbin by attaching a bobbin clip to the bobbin. The other end of the terminals is then available to be connected to a power source. The coil assembly is then placed within a fuel injector. When a current is introduced to the terminals through the power source, the wire creates a magnetic field which causes the coil assembly to energize, which in turn causes the guiding valve to open and allow fuel to pass through an opening in the injector valve seat.
A shortcoming of presently available coil assemblies is the inaccuracies of the method of mechanically pressing the terminals through the bobbin terminal posts because the terminals may bend or may be positioned incorrectly, causing the assembly to be non-useable. Another drawback to known processes is that a clip is added to the assembly to insure that the portion of the terminals containing the wire are fully rotated and secured into the framework of the bobbin. This clip may cause interference in the future assembly if the clip is not attached correctly. Also, this clip has a tendency to become unattached or lost if the clip is not attached correctly. The additional costs associated with re-application of the clip, lost time in failed assemblies due to the loss of the clip, or bent or inaccurately located terminals increase the cost of the injector on a per-vehicle basis.
SUMMARY OF THE INVENTION
It is, therefore, one object of the present invention to provide a fuel injector, for use in an internal combustion engine, having a simple and precise means of centering and securing the terminals in the coil assembly of a fuel injector. A feature of the present invention is to provide the coil assembly with open terminal posts that provide an entrance for the terminals via a translational push. The open terminal posts are configured such that the terminals are held in place securely yet allowed to rotate. To allow the terminals to be positioned properly, a pair of flange holding notches have been added to the bobbin as well. The open terminal posts and the flange holding notches allow the terminals to be more accurately positioned for height and depth, and thus the secured terminals are more readily available to receive a length of wire that is soldered to the terminals.
An additional feature of the present invention is to provide flange-locking notches that capture the terminals when rotated. This locking feature removes the need for bobbin clips that are used to make sure the terminals are correctly rotated and secured. Part quantity reduction and scrap reduction due to bobbin clip breakage are an advantageous by-product of the elimination of the bobbin clip. Further, there is no longer a need to have an operator to install the bobbin clip, thus further improving the throughput for assembling the bobbin.
Other features and advantages of the present invention will become apparent from the following detailed description that should be read in conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1
is a side view of a fuel injector having terminals attached to a power source;
FIG. 2
is a sectional view of the fuel injector of
FIG. 1
taken along line
2
—
2
without the power source attached;
FIG. 3
is an enlarged cross section of a portion of
FIG. 2
;
FIG. 4
is a side view of the bobbin according to a preferred embodiment of the invention;
FIG. 5
is a side view of the bobbin where the terminals have been installed in the non-rotated position and where the wire has been attached according to a preferred embodiment of the invention;
FIG. 6
is a top view of the bobbin with the terminals and wire attached in the rotated position according to a preferred embodiment of the invention; and;
FIG. 7
is a side view of FIG.
6
.
DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT
Referring to
FIGS. 1-3
where an electromagnetic fuel injector
10
generally has a body
12
, a nozzle assembly
14
, a valve member
16
and a multi-functional coil assembly
18
used to control the movement of the valve member
16
.
As illustrated, the body
12
is of cylindrical, hollow tubular configuration and has an external shape permitting direct insertion of injector
10
into a socket of an engine intake manifold (not shown).
The body
12
includes an enlarged upper solenoid case portion
20
and a lower end nozzle portion
22
of reduced internal and external diameter relative to the solenoid portion
20
. An external cylindrical cavity
24
is formed in the body
12
by a stepped bore therethrough that is substantially coaxial with the axis
26
of the body. In the illustration shown, the cavity
24
includes a cylindrical upper wall
28
, a cylindrical intermediate wall
30
and a cylindrical lower wall
32
. Wall
30
is of a reduced diameter relative to upper and lower wall portions
28
and
32
, respectively.
Multi-functional coil assembly
18
is disposed within the enlarged upper solenoid case portion
20
and includes a spool-like bobbin
34
supporting a wire
36
(shown as
222
on the preferred embodiments). A preferred embodiment of the bobbin
34
is detailed in
FIGS. 4 through 7
below. A resilient sealing member such as O-ring
40
is disposed between the bobbin
34
and a seal shoulder
44
in the cylindrical intermediate wall
30
. The bobbin
34
is provided with a central bore
46
therethrough configured to encircle the lower reduced diameter portion
48
of pole piece
50
. The bobbin
34
, in conventional designs, contains two hollow terminal posts (a preferred embodiment of the terminal posts
200
is shown in FIGS.
4
through
7
), each of sufficient diameter (0.56+/−0.02 mm in conventional designs) to receive and hold a terminal
52
of sufficient diameter (0.64+/−0.1 mm in conventional designs) therethrough, wherein each of the pair of terminals
52
is also operatively connected to an end of the wire
36
and each such terminal
52
extends from the terminal posts through the outer, overmolding casing
54
, to terminate in a connector
56
for connection of the fuel injector to a suitable source of electrical power in a manner well known in art.
Pole piece
50
includes an upper cylindrical portion
58
, a centrally located circular, radial flange portion
60
and the lower reduced diameter cylindrical pole
48
. The circular, radial flange portion
60
is slidably received at its outer peripheral edge within the cylindrical upper wall
28
of the body
12
to thereby close the enlarged upper solenoid case portion
20
of the body
12
and retain the multi-functional coil assembly
18
therein. The pole piece
50
is axially retained within the upper cylindrical portion of the body
12
by welding or otherwise suitable bonding its flange portion
60
to the shoulder
62
along the upper, opened end of the wall
28
.
Referring to
FIG. 4
, a preferred embodiment of the bobbin
34
is shown. The bobbin
34
has a first flange
214
, a second flange
212
, and a third flange
210
. The bobbin
34
has open terminal posts
200
each having a bottom portion
201
that are located on the third flange
210
. Terminal post diameters
202
are sized to allow terminals (shown as
209
in
FIGS. 5
,
6
and
7
) to be locked therein during installation. In a preferred embodiment, the terminal post diameters
202
are 0.63+/−0.05 mm to lock terminals
52
of conventional design and size (0.64+/−0.1 mm diameter). The bobbin
34
contains two flange holding notches
207
located on the third flange
210
for securing the terminals
209
during installation prior to rotation. At least one flange locking notch
204
is used to capture the terminals after rotation and is located on the second flange
212
. The strain relief
206
feature disposed between the second flange
212
and third flange
210
provides an engagement area to guide the wire
222
(shown in
FIGS. 5
,
6
and
7
) during installation on a terminal
209
and provides strain relief in the wire after the terminal is fully rotated. A winding bay portion
220
that is located between the second flange
212
and the first flange
214
will eventually be wrapped with the wire
222
prior to installing the bobbin
34
in a fuel injector.
Referring to
FIG. 4
, a preferred embodiment of the bobbin
34
is shown. The bobbin
34
has a first flange
214
, a second flange
212
, and a third flange
210
. The bobbin
34
has open terminal posts
200
having a bottom portion
201
that are located on the third flange
210
. Terminal post diameters
202
are sized to allow terminals (shown as
209
in
FIGS. 5
,
6
and
7
) to be locked therein during installation. In a preferred embodiment, the terminal post diameters
202
are 0.63+/−0.05 mm to lock terminals
52
of conventional design and size (0.64+/−0.1 mm diameter). The bobbin
34
contains two flange holding notches
207
located on the third flange
210
for securing the terminals
209
during installation prior to rotation. At least one flange locking notch
204
is used to capture the terminals after rotation and is located on the second flange
212
. The strain relief
206
feature disposed between the second flange
212
and third flange
210
provides an engagement area to guide the wire
222
(shown in
FIGS. 5
,
6
and
7
) during installation on a terminal
209
and provides strain relief in the wire after the terminal is fully rotated. A winding bay portion
220
that is located between the second flange
212
and the first flange
214
will eventually be wrapped with the wire
222
prior to installing the bobbin
34
in a fuel injector.
FIGS. 5 through 7
below show a preferred embodiment of the present invention at various stages of terminal assembly prior to placing the bobbin in a fuel injector.
FIG. 5
shows a preferred embodiment of the bobbin
34
during the initial installation phase of the terminals
209
and wire
222
prior to rotation. Each terminal
209
is engaged within the terminal post diameter
202
of one of the open terminal posts
200
such that a portion of the terminal
209
is engaged to the flange holding notch
207
. The wire
222
is wrapped around the winding bay portion
220
of the bobbin
34
and each end of the wire
222
is fluxed and soldered to a terminal
209
.
In
FIGS. 6 and 7
, the terminal
209
is shown in the rotated position. The terminal
209
has a wire
222
wrapped around a portion of the terminal
209
that is soldered or otherwise attached to the terminal
209
. The terminal
209
has been rotated into the bobbin
34
such that the end of the terminal
209
is engaged between the flange locking notch
204
and the bobbin
34
. The flange locking notch
204
eliminates the need for a locking clip (not shown) to be placed on the bobbin
34
to cover the end of the terminals
209
.
In a preferred embodiment of the present invention, the bobbin
34
is manufactured from injection molded nylon 6/6 or a similar plastic that incorporates the open terminal posts
200
, the flange locking notch
204
, and the flange holding notches
207
.
In operation, the assembly of the bobbin
34
with the terminals
209
and the wire
222
occurs in one operation with one operator, whereas at least one additional operation (and possibly one additional operator) is needed to attach the clip in previous embodiments. The improved method comprises pressing each terminal
209
through one of the open terminal posts
202
via a translational push such that a portion of each terminal
209
is disposed within one or the other flange holding notch
207
; wrapping a wire
222
around a winding bay portion
220
of the bobbin
34
; securing the wire
222
to each terminal
209
; and rotating the two terminals
209
such that each terminal
209
is disposed within the flange locking notch
204
. The bobbin
34
is then available to be placed in a fuel injector and connected to a power source as described above.
While one particular embodiment of the invention has been shown, it will be understood, of course, that the invention is not limited thereto since modifications may be made by those skilled in the art, particularly in light of the following teachings. It is therefore contemplated by the appended claims to cover any such modifications as incorporate those features that constitute the essential features of these improvements within the true spirit and scope of the invention.
Claims
- 1. A bobbin for use in a fuel injector comprising:a first flange; a winding bay portion adjacent to said first flange; a second flange having a flange locking notch adjacent to said winding bay portion; and a third flange adjacent to said second flange, said third flange having a first terminal post with a first hollow portion having a first diameter to accept a first terminal, said third flange having a second terminal post with a second hollow portion having a second diameter to accept a second terminal, wherein the diameter of said first diameter and said second diameter are substantially equal.
- 2. A bobbin according to claim 1, further comprising said first terminal having a first terminal diameter and said second terminal having a second terminal diameter terminal, wherein the diameter of said first terminal diameter and said second terminal diameter are substantially equal.
- 3. A bobbin according to claim 2, wherein said first terminal is disposed within said first terminal post and said second terminal is disposed within said second terminal post.
- 4. A bobbin according to claim 3, further comprising a wire having a first end and a second end, said wire being wrapped around said winding bay portion and secured to said first terminal and said second terminal.
- 5. A bobbin according to claim 4, wherein said wire is coupled to said first terminal by soldering and wherein said second end is coupled to said second terminal by soldering.
- 6. A bobbin according to claim 5, wherein said first terminal and said second terminal are disposed within said flange locking notch.
- 7. A bobbin according to claim 6, wherein said first terminal post comprises a first open terminal post and said second terminal post comprises a second open terminal post.
- 8. A bobbin according to claim 7, wherein said third flange further comprises a first holding notch and a second holding notch, wherein said first terminal is further disposed within said first holding notch and wherein said second terminal is further disposed within said second holding notch.
- 9. A bobbin according to claim 1, wherein said first flange, said second flange, said winding bay portion and said third flange are integrally molded from a plastic.
- 10. A bobbin for use in a fuel injector comprising:a first flange; a winding bay portion adjacent to said first flange; a second flange adjacent to said winding bay portion; and a third flange adjacent to said second flange, said third flange having a first open terminal post and a second open terminal post and a first flange holding notch and a second flange holding notch.
- 11. A bobbin according to claim 10, wherein a first terminal and a second terminal are coupled to the bobbin.
- 12. A bobbin according to claim 11, wherein said first terminal is disposed within said first open terminal post and said first flange holding notch and wherein said second terminal is disposed within said second open terminal post and said second flange holding notch.
- 13. A bobbin according to claim 12, wherein a wire having a first end and a second end is wrapped around said winding bay portion and coupled to said first terminal and said second terminal.
- 14. A bobbin according to claim 13, wherein said first end is coupled to said first terminal by soldering and wherein said second end is coupled to said second terminal by soldering.
- 15. A bobbin according to claim 14, wherein said second flange further comprises a flange locking notch, wherein said first terminal and said second terminal are disposed within said flange locking notch.
- 16. A bobbin according to claim 10, wherein said first flange, said second flange, said winding bay portion and said third flange are integrally molded from a plastic.
US Referenced Citations (5)