U.S. patent application number 10/417425 was filed with the patent office on 2004-05-13 for connector for automotive bridge rectifier assembly.
Invention is credited to De Petris, Peter S..
Application Number | 20040092147 10/417425 |
Document ID | / |
Family ID | 46203703 |
Filed Date | 2004-05-13 |
United States Patent
Application |
20040092147 |
Kind Code |
A1 |
De Petris, Peter S. |
May 13, 2004 |
Connector for automotive bridge rectifier assembly
Abstract
A connector for a re-manufactured automotive alternator includes
a first terminal blade and a second terminal blade within a
connector housing. The connector housing receives a mating housing.
The first terminal blade and the second terminal blade are flexibly
coupled to a common base by at least one respective bend. The first
and second terminal blades are adapted to mate to mating connectors
within the mating housing. The bend that couples the two blades to
the common base flexes to allow the first and second terminal
blades to move to adapt to varying positions of the mating
connectors within the mating housing.
Inventors: |
De Petris, Peter S.;
(Youngstown, NY) |
Correspondence
Address: |
KNOBBE MARTENS OLSON & BEAR LLP
2040 MAIN STREET
FOURTEENTH FLOOR
IRVINE
CA
92614
US
|
Family ID: |
46203703 |
Appl. No.: |
10/417425 |
Filed: |
April 15, 2003 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10417425 |
Apr 15, 2003 |
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10008303 |
Nov 6, 2001 |
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10008303 |
Nov 6, 2001 |
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09412931 |
Oct 5, 1999 |
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6327128 |
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60103682 |
Oct 8, 1998 |
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60103412 |
Oct 7, 1998 |
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60129738 |
Apr 16, 1999 |
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60139998 |
Jun 18, 1999 |
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Current U.S.
Class: |
439/246 ;
257/E23.08; 257/E25.015 |
Current CPC
Class: |
H01L 2924/12043
20130101; H01L 2924/01013 20130101; H01L 2924/01014 20130101; H01L
23/4334 20130101; H01L 2924/0105 20130101; H02K 11/25 20160101;
H01L 2924/01082 20130101; H01L 2924/01075 20130101; H01H 37/761
20130101; H01L 2924/014 20130101; H01L 2924/01029 20130101; H01L
24/02 20130101; H01L 2924/01004 20130101; H01L 2924/01039 20130101;
H01L 2924/13034 20130101; H01L 2924/01005 20130101; H01L 2924/01033
20130101; H01L 24/01 20130101; H01L 2924/01006 20130101; H01L
2224/13 20130101; H02K 11/046 20130101; H01L 24/13 20130101; H01L
2224/0401 20130101; H01L 23/3114 20130101; H01L 23/34 20130101;
H01L 2224/13099 20130101; H01L 2924/19041 20130101; H01L 24/10
20130101; H01L 25/071 20130101; H01L 2924/13034 20130101; H01L
2924/00014 20130101; H01L 2224/13 20130101; H01L 2924/00 20130101;
H01L 2924/12043 20130101; H01L 2924/00 20130101 |
Class at
Publication: |
439/246 |
International
Class: |
H01R 013/64 |
Claims
What is claimed is:
1. A connector for a re-manufactured automotive alternator,
comprising: a connector housing to receive a mating housing; and a
first terminal blade and a second terminal blade within the
connector housing, each of the terminal blades flexibly coupled to
a common base by at least one respective bend, the terminal blades
adapted to mate to mating connectors within the mating housing, the
bend flexing to allow the first and second terminal blades to move
to adapt to varying positions of the mating connectors within the
mating housing.
2. The connector of claim 1, wherein the bend has a semicircular
shape.
3. A connector for a re-manufactured automotive alternator,
comprising: a connector housing to receive a mating housing; and a
first terminal blade and a second terminal blade adapted to mate to
mating connectors within the mating housing, the terminal blades
corrugated to increase an effective thickness of the blades to
adapt the blades to varying widths or positions of the mating
connectors within the mating housing.
4. The connector of claim 3, wherein the corrugated terminal blades
comprise at least one crest and one trough.
Description
RELATED APPLICATIONS
[0001] This application is continuation of U.S. patent application
Ser. No. 10/008,303, filed on Nov. 6, 2001, which is a divisional
application of U.S. patent application Ser. No. 09/412,931, filed
on Oct. 5, 1999, which claims the benefit of priority under 35
U.S.C. .sctn. 119(e) to U.S. Provisional Patent Application No.
60/103,682, filed on Oct. 8, 1998, U.S. Provisional Patent
Application No. 60/103,412, filed on Oct. 7, 1998, U.S. Provisional
Patent Application No. 60/129,738, filed on Apr. 16, 1999, and U.S.
Provisional Patent Application No. 60/139,998, filed on Jun. 18,
1999.
[0002] BACKGROUND OF THE INVENTION
[0003] 1. Field of the Invention
[0004] The present invention relates to the field of automotive
rectifier assemblies. Particularly, the present invention relates
to a method and apparatus for preventing rectifier assemblies from
overheating.
[0005] 2. Description of the Related Art
[0006] Advances in technology have allowed for a reduction in the
size of automotive alternators (herein "alternators"). Although
alternators have become smaller, the electrical energy output
requirements have increased. Generally, recharging an automobile's
battery requires a current between 40 and 50 amperes. Combined with
the energy requirements of the air conditioning system, the
computer module, the car radio, the fans, and the lighting systems,
the overall current consumption can exceed 150 amperes.
[0007] The high current alternator is generally not able to
dissipate heat out of the rectifier module fast enough to prevent
semiconductor failure. The problem is particularly severe during
the summer months, when the ambient temperature is quite high, thus
reducing the rate of heat transfer between the rectifier module and
the surrounding environment.
[0008] Polyphase alternating current can be converted to direct
current suitable for use in an automotive electrical system by
conducting current through semiconductor diodes in a rectifier
circuit. The semiconductors may be affixed directly onto a heat
sink, as is illustrated by U.S. Pat. No. 5,005,069, or press-fit
into pre-punched holes in the heat sinks, as is illustrated by U.S.
Pat. No. 5,043,614. In other methods, such as that illustrated in
U.S. Pat. No. 4,799,309, the semiconductors are affixed onto
integrated heat sinks. The heat control methods identified above
are usually difficult to implement because the semiconductors are
extremely sensitive to heat, stress, and mechanical force applied
to the semiconductors during the manufacturing and installation.
The stress can cause premature semiconductor failure during vehicle
operation.
[0009] The likelihood of failure is especially great when the
semiconductors of the rectifier assembly are affixed onto a single,
integrated, aluminum heat sink. The semiconductors are usually
encapsulated with heat conductive epoxy, which prevents the
semiconductors from expanding or from dissipating heat efficiently.
The semiconductor overheating and failure conditions has been
historically demonstrated by the FORD IAR alternator catastrophic
failure scenario. Therefore, there is a need for a method of
ensuring that the rectifier assembly does not overheat when
semiconductors fail while not overstressing the semiconductors
during assembly.
[0010] Automotive power requirements utilizing a rectifier can
exceed 70 amperes. With the present day high under-hood
temperatures, along with the heat generated by the alternator and
the rectifier, this high current cannot safely pass through the
rectifier male terminal blades and into the female connector
terminals when the terminals are not properly mated.
[0011] Most rectifier assemblies use three male terminal blades
molded into a connector housing. The B+ blades that supply the
battery power are formed out of tin plated brass or steel and are
bent into a "U" configuration (usually a square bend molded into a
housing, and having no flexibility) to carry the high current. The
third independent blade is used to transfer low amperage stator
alternating current to the electric choke circuit.
[0012] In the prior art, when the original alternator, rectifier
and connector are manufactured, assembled and installed by the
manufacturer, the system operates quite well for several years.
However, after operating for several years, under the stress of
high current and high under-hood temperatures, the materials take
on a preset form, or memory.
[0013] Replacing a failed alternator presents a major problem for
the re-manufacturer and the installer because the installer must
force and pry off the tightly fit female mating connector. After
installing a remanufactured alternator, the mating connector is
mechanically distorted, thermally aged, or has a preset memory.
Thus, the connector terminal blades most likely will not align with
the female receptacle terminals, creating a high resistance loose
connection, causing arcing, over-heating, and introducing a fire
hazard.
[0014] In an attempt to solve the problem, many large volume
alternator re-manufacturers enclose a new connector plug with every
alternator sold. This practice is extremely expensive, and cannot
guarantee the rectifier contact blades will be properly aligned to
provide a low resistance tightly fit connection after the installer
forces the new connector into the re-manufactured alternator
rectifier.
[0015] Other alternator re-manufacturers recommend that their
customers perform a 6 pound pull test on the connector plug prior
to plugging it into the newly installed alternator. A 6 pound
weight is attached to a single male terminal blade. The blade is
then plugged into each of the three female receptacles. If the
weight causes the male blade to pull out of any one of the three
female receptacles, the existing automobile's connector must be cut
out and a new connector is spliced into the circuit. The installer
must then force the new female connector from side to side, while
pushing it downward into the male housing, allowing the male blades
to enter into the female receptacles. This action causes the male
blades to bend.
[0016] Because the male terminal blades cannot self-align, they
lose their required contact surface area, and create a high
resistance connection. This connection becomes a hot spot within
the connector housing because of the high operating current
conducted through it. The extra heat generated within the
re-manufactured alternator will not allow it to dissipate out of
the rectifier. As heat continues to build up within the rectifier
it either fails or becomes a fire hazard.
SUMMARY OF THE INVENTION
[0017] In accordance with the present invention, a rectifier
assembly employs semiconductor circuits that automatically open
whenever the semiconductors fail and dissipate a predetermined
level of heat.
[0018] In one embodiment, the present invention utilizes
spring-loaded terminals to connect the semiconductor circuits such
that, when a failure occurs, the high temperature causes a
preselected soldered joint to melt. Once melted, a compressed
spring, under the joint, holds the terminals away from one another
to open the failed circuit and stop the current flow.
[0019] In one embodiment, the rectifier assembly includes six
spring-loaded diodes affixed onto two copper heat sinks. The heat
sinks provide cooler and more efficient operation as described in
U.S. Pat. No. 5,659,212, incorporated herein by reference.
[0020] The present invention is concerned with the high power and
under-hood temperatures required by modern day automotive
electronics and the catastrophic fire and melt down hazards caused
by overheated semiconductors. The method of the present invention
avoids overstressing the semiconductors by preventing the circuits
from operating in a range of operation that is beyond the
semiconductor's handling specifications. The thermal protection of
the present invention virtually eliminates the automobile's
catastrophic fire hazard, the dead battery nuisance conditions, and
other conditions that are associated with semiconductor
failures.
[0021] The present invention also offers a method for assembling
rectifiers without overstressing the diodes in the process of
securing the diodes to the rectifier assembly. The method includes
providing a protective cup that is used to hold the semiconductor
diode and absorb stress that may otherwise be absorbed by the
semiconductor body.
[0022] The rectifier of the present invention employs a terminal
connector that utilizes dimpled or detented (e.g., corrugated),
spring-loaded, self-aligning male terminal blades to compensate for
tolerances between all manufactured connectors. The terminal blades
also compensate for the existing automobile connector which may be
out of tolerance, because of thermal aging, mechanical abuse, or
preset memory.
BRIEF DESCRIPTION OF THE DRAWINGS
[0023] FIG. 1 illustrates a rectifier bridge alternator
circuit;
[0024] FIG. 2 illustrates a rectifier bridge alternator circuit
with the thermal safety disconnects of the present invention;
[0025] FIG. 3A illustrates a Ford 3G rectifier bridge;
[0026] FIG. 3B illustrates a Ford 3G rectifier bridge with thermal
safety disconnects;
[0027] FIG. 4A illustrates a rectifier assembly with safety
washers;
[0028] FIG. 4B illustrates a side view of a diode pair assembly
with a thermal safety washer in place;
[0029] FIG. 5A illustrates a side view detail of the rectifier
assembly of FIG. 4A;
[0030] FIG. 5B illustrates a rectifier assembly and the stator
field coil circuits;
[0031] FIG. 5C illustrates the capacitor assembly of the rectifier
circuit;
[0032] FIG. 6 illustrates details of a button-type semiconductor
with a spring pull-off, contact safety release;
[0033] FIG. 7A illustrates a cross section of a pan type
semiconductor assembly with safety washers;
[0034] FIG. 7B illustrates a cross section of the pan type
semiconductor assembly of FIG. 7A after a thermal failure
condition;
[0035] FIG. 7C illustrates an alternative embodiment of a diode
pair assembly;
[0036] FIG. 8A illustrates a semiconductor prior to being pressed
into a heat sink;
[0037] FIG. 8B illustrates the semiconductor of FIG. 8A after being
pressed into the heat sink;
[0038] FIG. 8C illustrates the semiconductor assembly of FIG. 8B
after a thermal failure condition;
[0039] FIG. 9 illustrates a rectifier press-fit semiconductor diode
assembly;
[0040] FIG. 10 illustrates the diode assembly of FIG. 9 after a
thermal failure condition;
[0041] FIG. 11 illustrates a spring loaded semiconductor diode
assembly;
[0042] FIG. 12 illustrates the diode assembly of FIG. 11 after a
thermal failure condition;
[0043] FIG. 13A illustrates an exploded view of an alternative
embodiment of a diode pair safety connector assembly;
[0044] FIG. 13B is a side view illustration of the completed
assembly of FIG. 13A;
[0045] FIG. 14 illustrates an expanded view of an alternate
embodiment of a diode pair safety connector assembly;
[0046] FIG. 15 illustrates a connection of diode pairs by a safety
bracket;
[0047] FIG. 16 illustrates the positive heat sink of FIGS. 4A and
5A;
[0048] FIG. 17 illustrates the negative heat sink of FIGS. 4A and
5A;
[0049] FIG. 18 illustrates an alignment rail that ensures proper
mating with the female connector from the automobile wiring
harness; and
[0050] FIG. 19 illustrates the insulating gasket of FIGS. 4A and
5A.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0051] The structure and operation of the semiconductor safety
assembly of the present invention will be discussed with reference
to embodiments of automotive rectifier assemblies. First, a problem
associated with semiconductor diodes of automotive rectifier
assemblies will be discussed. Second, several modification to
existing rectifier assemblies will be illustrated. Next, the
structure of semiconductor diode safety disconnects will be
discussed with reference to illustrations of rectifier assemblies
and diode pair assemblies.
[0052] Although the safety assemblies of the present invention are
disclosed with reference to an automotive rectifier assembly, the
disclosure is equally applicable to other circuits that employ
semiconductor components that are susceptible to overheating as a
result of a failure condition.
[0053] One problem solved by the safety assemblies of the present
invention relates to alternator rectifier circuit semiconductor
diode failures. Once an alternator is installed in a vehicle, all
semiconductor diodes are electrically connected to the battery,
completing a number of potential short circuit paths to the ground.
The charging system's wiring harness usually incorporates a 12 AWG
fuse link safety circuit, for fire and meltdown protection. The
fuse, however, only provides an illusion of safety, as is discussed
below.
[0054] Heat and voltage transients degenerate semiconductor
switches and cause undesired reverse current leakage through the
semiconductor junction. The leakage can lead to excessive junction
heating. Once overheated, the semiconductor switch may be damaged
beyond recovery. The semiconductor switch may also lose its
blocking characteristics and allow current to flow in both
directions. The excessive heat can then cascade into and damage
other semiconductor switches of the same circuit.
[0055] Generally, there are no cut out relays or switches that open
the semiconductor circuits of the rectifier system when a vehicle
is shut down. Thus, the circuits usually remain electrically "HOT"
when the vehicle is shut down. Further, the alternator's cooling
system is also shut down when a vehicle is not operating, thus
leaving the circuits thermally vulnerable. Latent heat remains in
the thick rectifier housing and conducts back into the
semiconductors. Thus, the alternator of the unattended shut-down
vehicle is slowly heating up, as heat cascades from one
semiconductor to another, causing semiconductor failures, and
generating enough heat so as to potentially ignite an under-hood
fire.
[0056] When the semiconductors fail, the current level is generally
not high enough to melt the 12 AWG fuse. The semiconductors usually
fail with a combined resistance of approximately 0.3 ohm. Thus, a
40 ampere current flows through the failed circuit. The level of
current translates to 480 watts generated within the rectifier
case. The 480-watt power output is 13 times greater than an average
37-watt soldering iron used in the electronics industry.
[0057] The failed semiconductors become high wattage heaters that
are controlled by the hot silicon's resistance, overheating the
path through the copper components, melting the plastic affixing
the terminals, melting the epoxy fillers, and igniting any grease
or oil on the wiring harness insulation. Furthermore, the leakage
path does not conduct enough current to melt the 12 AWG fuse link.
Therefore, there is only an appearance of safety when employing the
fuse link. Once started, the meltdown continues until the battery
is discharged or manually disconnected. Further, rectifiers that
fail without a catastrophic failure are still a nuisance to the
general public because of the required service calls, the towing,
and the repair costs.
[0058] FIG. 1 illustrates a typical rectifier bridge configuration
of an alternator circuit. The rectifier bridge circuit 100 is
connected to the stator windings 101, 102, 103. The rectifier
bridge circuit 100 is also connected to the negative terminal 112
of the battery 114. The rectifier bridge circuit 100 includes six
diodes 104-109. A first set of diodes 104-106 is thermally and
electrically coupled to a first heat-sink (FIG. 4A). A second set
of diodes 107-109 is thermally and electrically coupled to a second
heat-sink. The anodes of the first set of diodes 104-106 are
connected to the cathodes of the second set of diodes 107-109,
thereby forming three diode pairs 104/107, 105/108, 106/109 that
are connected in series between the first heat-sink and the second
heat-sink. Leads that extend from the alternator's stator windings
101, 102, 103 are electrically connected to the cathode/anode
connections of the diode pairs 104/107, 105/108, 106/109. A lead
116 to the voltage regulator is connected between a diode pair
106/109. The lead 116 is also optionally connected to an electric
choke (not shown) if an electric choke is used. Output terminals
115 from the first heat sink are coupled to the positive post 111
of the battery 114 by a fusible link 113. An output terminal 118 in
FIG. 1 represents the connection from the second heat sink to the
common ground when the alternator with the rectifier bridge circuit
100 is installed on an engine. The common ground is also connected
to the negative post 112 of the battery 114 to complete the circuit
from the rectifier bridge circuit 100 to the battery 114.
[0059] FIG. 2 illustrates a rectifier bridge circuit 200 that
includes thermal safety disconnect elements 201-206 (herein after
"disconnect elements") in accordance with the present invention.
The disconnect elements 201-206 are coupled along the potential
circuit paths from the positive terminal 111 to the negative
terminal 112 of the battery 114. The disconnect elements 201-206
are coupled in series with the circuit paths of the diodes 104-109,
adjacent to each diode. The arrows along the circuit lines in FIG.
2 illustrate the direction of voltage drop when current flows
through the failed diodes. For example, a first disconnect element
201 is in the circuit path associated with a first diode 104. The
first disconnect element 201 is responsive to the heat dissipated
from the first diode 104 such that the first disconnect opens the
circuit path when the first diode overheats. Generally, the
disconnect elements 201-206 are located in positions where the heat
dissipated from the failed diodes 104-109 can best be sensed. A
special disconnect element 208 is used to open the circuit
associated with the lead 116 to the voltage regulator and to the
electric choke.
[0060] A first diode 104 and a second diode 108 are highlighted to
illustrate the current path from the positive terminal 111 through
the two failed diodes, and the stator coils 101, 102, to the
negative terminal 112. As may be appreciated, current from the
stator assembly can flow in the reverse direction to the ground
when a pair of diodes fail. During a failure of the two highlighted
diodes 104, 108, the heat generated by the diodes, as a result of
the excess current, melts the adjacent disconnect elements 201, 205
to open the circuit path of the diodes. The stator coils 101, 102,
103 along with the six diodes 104-109, and the "S" lead 116,
provide twelve possible paths to ground.
[0061] FIG. 3A illustrates the circuit arrangement of a Ford 3G
alternator. The rectifier circuit includes eight diodes 304-311
that form four diode pairs 304/307, 305/306, 308/309, and 310/311.
The diode pairs 304/307, 305/306, 308/309, 310/311 are coupled to
the stator coils 301-303 and to the battery terminals (not shown)
in a similar manner as the diode pairs and stator coils of FIG. 1.
The fourth diode pair 305/306 provides a connection from the center
of the dual "Y" stator.
[0062] FIG. 3B illustrates the Ford 3G alternator circuit of FIG.
3A after undergoing modifications to include disconnect elements
336. The disconnect elements 336 are provided adjacent to each
diode so as to control the flow of current through the associated
diode. The disconnect elements 336 cut the flow of current in the
associated circuit when the corresponding diode overheats.
[0063] As discussed below in connection with FIGS. 4A, 4B, and 5A,
the disconnect elements used in the circuit of FIG. 2 and in the
circuit of FIG. 3B are preferably safety spacer washers that have
an inside diameter of approximately 0.06 inch, an outside diameter
of approximately 0.22 inch, and a thickness of approximately 0.1
inch. Alternatively, the thickness is approximately 0.06 inch. The
safety washers are advantageously made out of tin that has a
negligible electrical resistance and that has a melting temperature
of approximately 232 degrees centigrade. The dimensions of the
safety washer may also vary with the location within the rectifier
assembly.
[0064] FIG. 4A illustrates a rectifier assembly 425 with the
disconnect elements of the present invention. The rectifier
assembly 425 is preferably made of brass, or beryllium, that is
bent, or is formed, to shape. The rectifier assembly 425 includes a
connector assembly 429 which has two corrugated B+terminals 431A,
431B that are guided into a phenolic type housing 426. An alignment
rail 427 aligns and polarizes the female connector (not shown) from
the automobile wiring harness. When fully engaged, the locking
ramps 428 secure the corrugated terminals 431A, 431B to the female
connector. The corrugated terminals 431A, 431B are discussed in
further detail below with reference to FIG. 18.
[0065] A third terminal 430, generally referred to as the "S"
sensing terminal, is fitted with a safety washer 437. The "S"
terminal 430 fits into a third slot in the rectifier assembly 425.
The "S" terminal 430 is coupled to a first set of semiconductors,
106, 109, via a pair of terminal brackets, 434/435. The "S"
terminal 430 is formed in a corrugated configuration so as to
increase its width and ensure proper connection with potentially
worn out connectors. The safety washer 437 melts when overheated to
disconnect the "S" sensing terminal. The safety washer 437
corresponds to the special disconnect 208 in FIG. 2.
[0066] The pair of terminal brackets 434/435, 443/444, 445/446 are
coupled together by safety washers 436A, 436B, 436C. A first set of
terminal brackets 434/435 is pressed against the diode contacts of
a first pair of diodes 106/109 by an insulated compression spring
438A. The first set of terminal brackets 434/435 is held together
by a safety washer 436A that is soldered to the terminal brackets.
A second diode pair 105/108 is coupled to a second set of terminal
brackets, 443/444 by a spring 438B and by a safety washer 136B. A
third diode pair 104/107 is coupled to a third set of terminal
brackets 445/446 by a spring 438C and by a safety washer 136C. Four
hold-down screws 454, inserted through four nylon bushings 450,
secure the rectifier assembly 425, the terminal plate 429, the
positive heat sink 451, a gasket 452, and the negative heat sink
453 to the alternator body.
[0067] FIG. 4B is a side view of an arrangement of a diode pair
assembly that is used in the rectifier assembly of FIG. 4A. The
diode pair assembly includes the safety washer 436A, the insulated
compression spring 438A, the pair of terminal brackets 434/435, and
the pair of diodes 106/109. The spring is preferably a Teflon.RTM.
coated compression spring. As discussed above, the safety washer
436A is soldered between the terminal brackets 434/435. The safety
washer 436A provides a conductive path between the terminal
brackets 434/435. The two other diode pair assemblies of the
rectifier assembly of FIG. 4A are similarly arranged.
[0068] FIG. 5A illustrates a side view of the rectifier assembly
425 of FIG. 4A. The rectifier assembly 425 includes the rectifier
assembly components of FIG. 4A when assembled together.
[0069] In operation, the corresponding safety washer melts when a
failed diode dissipates excessive heat. The melted safety washer
opens the circuit path between the terminal brackets to disconnect
the failed diode from its circuit paths. The terminal brackets are
held apart by the compressed spring positioned between the terminal
brackets.
[0070] Although tin safety washers are used in the illustrated
apparatus, various types of melting materials can be used. Further,
the melting material may be configured as washers, tabs, or other
shapes that suit the particular apparatus. Although the illustrated
embodiment uses insulated compression springs and melting material,
which force the failed circuit to disconnect by disconnecting both
the positive semiconductor and the negative semiconductor, a
similar effect can be achieved by only disconnecting one
semiconductor of a conducting pair to open the circuit to ground,
for example.
[0071] FIG. 5B is a second perspective view of an assembled
rectifier that includes the components of FIG. 4A. The two
B+parallel terminals 429 are formed to receive the female connector
from the automobile wiring harness. The stator coils 101, 102, 103
(shown pictorially) are coupled to the rectifier assembly 425 by a
connector 563 that mates with the terminal brackets 446, 444, 435.
Thus, the stator coils 101, 102, 103 are coupled to the bracket
terminals 446, 444, 435 that provide the common connection points
between the diodes in the diode pairs.
[0072] FIG. 5C illustrates the capacitor module of the rectifier
assembly of FIG. 4A. A capacitor 510 is coupled to the positive
heat sink 451 by a screw 454 and a nylon bushing 450. The capacitor
510 includes a first connector ring 561 and a second connector ring
562 to couple the capacitor between the positive terminal 111 and
the negative terminal 112 of the battery, as is illustrated in FIG.
1.
[0073] FIG. 6 illustrates a diode 106 with a spring pull-off
thermal safety release. The apparatus utilizes terminals that
include spring-loaded contacts, which disconnect when a diode
overheats. A lead 602 has a first end that defines a nail head
contact 686. The lead 602 extends through an opening in a circuit
terminal 634. The circuit terminal 634 is adapted to rest on the
diode 106 without touching the diode's electrical contact 696. As
may be appreciated from FIG. 6, the terminal body 695 is thus
insulated from the diode's electrical contact 696.
[0074] The nail head contact 686 is soldered to the diode's
electrical contact 696 by a low melting point solder 681. The lead
602 is soldered to the terminal body 695 by using a higher melting
point solder 685 than that which was used to couple the nail head
contact 686 to the diode's electrical contact 696. A clearance 699
within the circuit terminal 634 allows for the release of the nail
head contact 686 from the diode's electrical contact 696 when the
solder 681 melts.
[0075] A second end 680 of the lead 602 is shaped into an arrow
head. The second end 680 of the lead 602 extends from a small
opening in a conical spring 672 such that the spring is compressed
by the second end 680 of the lead 602.
[0076] In operation, the terminal assembly is used to open the
circuit associated with a diode when the diode generates heat in
excess of a threshold. The heat radiated by a failed diode 106
increases the temperature of the low melting point solder 681
between the nail head contact 686 and the diode's electrical
contact 696. The increase in temperature causes the low melting
point solder 681 to melt. Although, the higher melting point solder
685 remains solid, it only has sufficient mechanic strength to hold
the lead 602 in place adjacent to the face of the spring 672 when
the low melting point solder 681 is also solid. Thus, when the low
melting point solder 681 melts in response to the high temperature,
the pressure applied to the second end of the lead 602 by the
spring 672 forces the nail head contact 686 away from the diode's
electrical contact 696. The electrical connection between the lead
602 and the diode 106 is thereby opened. Further, the electrical
connection between the diode 106 and the terminal 634 is also
opened because the terminal is electrically connected to the diode
only by the lead 602.
[0077] FIG. 7A illustrates a pan-type semiconductor terminal
assembly. The semiconductor diode 783 is nested in a cavity 779 of
a heat sink 751. A safety washer 736 is pressed against a stator
terminal 734 by a spring 738. A lead 780 extends from the diode's
contact through the safety washer 736. Solder 781 is used to couple
the lead 780 to the stator terminal 734 and to the safety washer
736.
[0078] FIG. 7B illustrates the terminal assembly of FIG. 7A after
an overheated condition that causes a failure. When the
semiconductor diode 783 overheats, the solder 781 and the safety
washer 736 melt. The removal of the solder 781 opens the diode's
electrical circuit because the diode 783 is electrically coupled to
the stator terminal 734 by the solder and the spring 738 is
electrically insulated.
[0079] FIG. 7C illustrates a diode pair assembly which employs low
melting point solder to open the overheated diode circuit. The
diode pair assembly includes a first diode 106, a second diode 109,
a terminal bracket 702, a first insulated compression spring 706,
and a second insulated compression spring 710. The first diode 106
is located within a cavity in the base of the diode pair assembly.
The first diode 106 is mechanically held against the base of the
diode pair assembly by a first portion 703 of a terminal bracket
702. The first portion 703 of the terminal bracket 702 is
positioned over the first diode 106. The first portion 703 of the
terminal bracket 702 is forced downward towards the first diode 106
by the first compression spring 706. The first compression spring
706 is positioned between the terminal bracket 702 and the bottom
portion of the connector locking ramp 428 (FIG. 4). The second
diode 109 is positioned below a second portion 705 of the terminal
bracket 702. The second portion 705 of the terminal bracket 702 is
held in place on top of the second diode 109 by a low melting point
solder 708. The low melting point solder 708 mechanically and
electrically connects the second portion 705 of the terminal
bracket 702 to a stator terminal 709. A second compression spring
710 is positioned below the center portion of the terminal bracket
702. The second compression spring 710 is secured by a pin 707. The
pin 707 extends through an opening in the terminal bracket 702 and
an opening in the heat sink.
[0080] In operation, when a diode fails and overheats, the low
melting point solder 708 melts to disconnect the second portion 705
of the terminal bracket 702 from the stator terminal 709. The
second compression spring 710 forces the second portion 705 of the
terminal bracket 702 away from the stator terminal 709. Thus, the
electrical circuit between the first diode 106, the second diode
109, and the stator terminal 709 is opened.
[0081] FIG. 8A illustrates a semiconductor diode 892 prior to being
pressed into a heat sink 891. A lead 880 from the diode 892 extends
through a safety washer 836. The lead 880 is coupled to the safety
washer 836 by a low melting point solder 881. The solder 881 and
the washer 836, provide an electrical connection between the diode
892 and the stator terminal 834, which is opened when the rectifier
assembly overheats.
[0082] FIG. 8B illustrates the semiconductor diode 892 as installed
in the heat sink 891. As may be appreciated from FIG. 8B, when
installed the lead 880 is soldered in place, and is under
compression.
[0083] FIG. 8C illustrates the semiconductor diode 892 after an
overheat condition. When the diode 892 overheats, the solder 881
and the safety washer 836 melt. The cleared solder 881 creates a
gap between the lead 880 and the stator terminal 834 to open the
circuit connection from the diode to the stator terminal 834. Thus,
the arrangement of FIGS. 8A, 8B, and 8C eliminates the use of the
spring underneath the washer in the arrangement of FIGS. 7A, and
7B.
[0084] As discussed below in connection with FIG. 9 and FIG. 10, in
another embodiment, a copper cup press fit semiconductor diode is
coupled to a protective cup by a tin/copper type low resistance,
low melting temperature, metal spacer disc that is soldered to the
semiconductor contact surface. When the semiconductor fails and
becomes an electrical heater instead of a switching and blocking
device, the spacer disc melts and opens the circuit. A collection
area within the copper cup provides room for the melted metal to
clear the diode contact surface.
[0085] FIG. 9 illustrates a rectifier press fit semiconductor diode
assembly with thermal disconnect. A silicon semiconductor chip 902
is coupled to a platform 912 in the bottom of the cup 900. A
thermal safety disc 913 is coupled to the electrical contact of the
chip 902. The lower end 906 of an axial lead 905 is coupled to the
thermal safety disc 913 via solder 914. The upper end of the axial
lead 905 extends up through an insulator 907, which is then sealed
with epoxy 904. The upper end of the axial lead 905 is affixed to
the rectifier bridge circuit terminal 909 by solder 910.
[0086] FIG. 10 illustrates the diode assembly of FIG. 9 after the
thermal safety disc 936 has melted away from the semiconductor,
leaving an open circuit between the semiconductor 902 and the lower
end of the axial lead 906. A collection area 903 allows the melted
disc 913 and solder 914 to flow away from the semiconductor contact
area.
[0087] In another embodiment, shown in FIG. 11 and in FIG. 12, a
conical compressed spring is affixed to an axial lead. The opposite
end of the spring is compressed against the insulating material of
the pan cup. The spring is preloaded so as to pull the
semiconductor contact away when the solder melts. This action stops
the current flow through the semiconductor circuit. Prior to
opening the circuit, the generated heat conducts up along the axial
lead from the semiconductor to melt the soldered lead of the
rectifier bridge terminal. This allows the lead to be forced
upwards, to open the semiconductor circuit.
[0088] FIG. 11 illustrates a pan-type diode assembly, which
includes a semiconductor 1102 affixed to the inside of a copper pan
1100 by solder 1112. The nail head 1120 of the axial lead 1105 is
affixed to the semiconductor 1102 by solder 1112. The axial lead
1105 terminates at the rectifier bridge terminal 1109 and is
soldered using a lower melting temperature solder 1110. A locking
clip 1118 is used to lock a compression spring 1117 to a bend 1115
in the axial lead 1105.
[0089] FIG. 12 illustrates the pan type rectifier diode assembly of
FIG. 11 in a failed, overheated condition. Excessive heat from the
reverse current flow causes the solder 1112 to melt at the
connection point between the nail head 1120 and the semiconductor
1102. The heat also melts the solder 1110 at the opposite end of
the lead 1105 to allow the compression spring 1117 to push the
axial lead 1105 up through the terminal 1109. The nail head 1120 is
thus allowed to lift off the semiconductor 1102 and open the
circuit between the semiconductor and the axial lead 1105. Once the
circuit is opened, the current flow is stopped. The compression
spring 1117 pushes the clip 1118 upward at the stress relief bend
1115 of the axial lead 1105 and pushes the potting material 1116
upward to open the internal circuit of the cup assembly.
[0090] FIG. 13A illustrates an alternate embodiment of a diode pair
assembly 1301 employing safety washers. The diode pair assembly
1301 includes a first diode 1302, a second diode 1304, a terminal
connector 1306, a spring 1308, and a safety washer 1312. The first
diode 1302 is coupled to the positive terminal of the diode pair
assembly 1301 and to a first portion 1318 of the terminal connector
1306. A second portion 1314 of the terminal connector 1306 is
coupled to the second diode 1304. The terminal connector 1306 rests
on the second diode 1304 by using a plurality of standoffs 1317
that maintain the diode's electrical contact spaced apart from the
second portion 1314 of the terminal connector. A safety washer 1312
is positioned below the spaced apart terminal connector 1306. The
spring 1308 is placed between the portions 1314, 1318 of the
terminal connector 1306 to maintain the portions of the terminal
connector spaced apart from one another. A circuit terminal 1316 is
formed at an end of the terminal connector 1306. Solder 1310 is
used to connect the diodes 1302, 1304 to the safety washer 1312 and
to the terminal connector 1306. FIG. 13B illustrates the components
of the diode pair assembly 1301 when assembled together between a
positive heat sink 1320 and a negative heat sink 1322. An
insulating gasket 1324 separates the positive heat sink 1320 and
the negative heat sink 1322.
[0091] In operation, the diode pair assembly disconnects the
electrical connection between the diodes 1302, 1304 when the level
of heat absorbed by the safety washer 1312 melts the safety washer.
The safety washer 1312 facilitates the electrical connection
between the second diode 1304 and the terminal connector 1306.
Thus, when the washer 1312 melts, the electrical connection between
the diode 1304 and the terminal connector is eliminated. The
electrical connection between the diode 1304 and any other
component of the diode pair is also eliminated. Therefore, the
diode pair assembly 1302 provides a thermally safe connection
between two diodes.
[0092] FIG. 14 illustrates a diode pair assembly 1401 that employs
a meltable terminal connector. The embodiment of FIG. 14 eliminates
the safety washer from the assembly of FIGS. 13A and 13B. The diode
assembly includes a first diode 1402, a second diode 1404, a
circuit terminal 1406, a connector terminal 1415, and an optional
insulated spring 1410. The first diode 1402 is coupled to the
circuit terminal 1406 and to a first end 1414 of the terminal
connector 1415 by solder 1416. The second end 1412 of the terminal
connector 1415 is coupled to the second diode 1404 by solder 1416.
An optional spring 1410 may be provided between the ends 1412, 1414
of the terminal connector 1415 to separate the diodes 1402, 1404
from one another when the terminal connector melts away. In
operation, when the diodes 1402, 1404 overheat, the terminal
connector 1415 melts so as to disconnect the circuit path between
the diodes.
[0093] FIG. 15 illustrates another embodiment of the safety
disconnects of the present invention. The diodes 1501,1502 are
coupled together by an L-shaped bracket 1504 and a low melting
point connection plate 1505. The L-shaped bracket 1504 is soldered
to the connection plate 1505 to secure a compressed spring 1503
between the diode pair 1501/1502. The circuit path of the diode
pair 1501/1502 flows through the connection plate 1505. When a
diode overheats, the connection plate 1505 melts to open the
connection. The spring pushes the diodes 1501, 1502 away from one
another. The use of a melting connection plate 1505 advantageously
eliminates the safety washers from the rectifier assembly.
[0094] FIG. 16 illustrates the positive heat-sink 451 of FIGS. 4A
and 5A. The positive heat sink 451 includes a vertical bent portion
and a horizontal base portion. The vertical bent portion includes
cavities 455 for securing the diodes of the rectifier assembly 425
in position.
[0095] FIG. 17 illustrates the negative heat sink 453 of FIGS. 4A
and 5A. The negative heat sink 453 includes a vertical bent portion
and a horizontal base portion. The horizontal base portion in
intended to serve as the bottom element in the rectifier assembly
configuration that is illustrated in FIG. 4A. As may be
appreciated, the elements that are stacked on the negative heat
sink 453 to form the rectifier assembly body include, in order, the
gasket 452, the positive heat sink 451, and the terminal connector
assembly 429. The vertical bent portion of the negative heat sink
453 includes cavities 457 for securing the diodes of the rectifier
assembly 425 in position.
[0096] FIG. 18 illustrates the terminal connector 429 of FIGS. 4A
and 5A. The terminal connector 429 is used to couple the female
wiring harness to the rectifier assembly as illustrated in FIG. 4A.
The terminal connector incorporates self-aligning corrugated
terminal blades 431A, 431B that are formed with a plurality of
bends to allow for a variation in the lateral spacing in a female
connector. An additional large bend 460 at the base of each blade
431A, 431B provides additional flexibility with respect to the
positions of the two blades. For example, a worn-out female harness
may be spaced wider than a new female harness. The terminal
connector 429 can mate with such a worn-out connector because of
the effective thicknesses of the blades provided by the corrugation
and because the bends 460 at the base of the blades allow the
blades to adapt to different positions of the mating
connectors.
[0097] The connector material is a tempered half-hard beryllium,
approximately 0.031 inches thick. The connector 429 conducts the
required current without overheating. The connector's temper allows
it to spring back into any usable position to accommodate all
connectors used in the alternator application. The corrugated
terminal blades 431A, 431B include a plurality of detents or
alternating dimples, approximately 0.125 inch from centerline to
centerline, which expands the connector's contact gripping
thickness from 0.031 inches to approximately 0.037 inches.
[0098] In use, the female connector is pushed into the terminal
connector 429 to secure the corrugated blades 431A, 431B to grooves
in the female connector. The corrugated blades 431A, 431B are thick
enough so as to securely reside within the grooves of the female
connector. The female connector is further held in place by a pair
of detents on the terminal cover as discussed with reference to
FIG. 4A. Thus, the irregularly shaped male blades allow for the
terminal 429 to properly couple to a female connector after the
connector has been removed from an original rectifier and may have
become distorted or worn-out. The terminal connector 429 of the
present invention does not increase the likelihood that the
connector will fail.
[0099] FIG. 19 illustrates an insulating gasket 452 that is used in
the rectifier of the present invention. The insulator gasket 452 is
stamped out of a fiberglass reinforced, phenolic-type material,
which is approximately 0.012 inches thick and has a compression
strength of 65,000 psi (pounds per square inch). The gasket 452
separates the two copper heat sinks 451, 453, from one another. The
inside area of the gasket 452 is stamped out to form two openings
458. During assembly of the rectifier, the openings 458 in the
gasket 452 are filled with a thermally conductive (i.e., heat
transferring), electrically non-conductive grease to enhance the
transfer of a portion of the generated heat to the alternator
housing.
[0100] Although the invention has been described in terms of
certain preferred embodiments, other embodiments that are apparent
to those of ordinary skill in the art, including embodiments which
do not provide all of the features and advantages set forth herein,
are also within the scope of this invention. Accordingly, the scope
of the invention is defined by the claims that follow.
* * * * *