Electrical distribution center

An electrical distribution center includes an upper housing, a circuit board disposed in the upper housing, and a lower housing having a plurality of lower terminal receiving cavities and a plurality of alignment cavities. A plurality of terminals is mounted on the circuit board such that each terminal is in electrical communication with a respective electrically conductive member. The terminals have contact portions below the circuit board and disposed in the lower terminal receiving cavities such that each of the terminals extends from the circuit board no more than a first predetermined distance. A plurality of alignment posts are fixed to the circuit board and received within the alignment cavities such that each of the alignment posts extends from the circuit board at least a second predetermined distance which is greater than the first predetermined distance.

TECHNICAL FIELD OF INVENTION

The present invention relates to an electrical distribution center; more particularly to an electrical distribution center having a circuit board disposed between an upper housing and a lower housing; and even more particularly to such an electrical distribution center where the circuit board includes features fixed thereto which interface with corresponding features of the lower housing to align the circuit board to the lower housing during assembly.

BACKGROUND OF INVENTION

Electrical distribution centers are being widely used in automobiles. The electrical distribution center is a central junction box or block system designed as a standalone assembly which can package various fuses, relays, and other electrical devices in a central location. The electrical distribution centers not only reduce costs by consolidating these various functions into one block, but the electrical distribution centers also reduce the number of cut and spliced leads which help to ensure reliability. Such electrical distribution centers include provisions for electrically connecting a power source and electrical devices housed in the junction block to electrical wiring harness connectors for supplying power and control signals to various electrical systems of the automobile such as an air conditioning system, a fuel system, lighting circuits, instrument panels and to provide signals to engine and auxiliary systems such as anti-lock brake wiring assemblies.

Polehonki et al. entitled “On Harness PCB Electrical Center” and assigned U.S. Pat. No. 7,727,022; the disclosure of which is incorporated herein by reference in its entirety; discloses an electrical distribution center assembly having an upper housing, a circuit board, and a lower housing. The upper housing includes a plurality of upper terminal receiving cavities and the lower housing includes a plurality of lower terminal receiving cavities. The circuit board is disposed in the upper housing below the upper terminal receiving cavities and includes a plurality of terminals mounted thereto which have contact portions above the circuit board that are disposed in the upper terminal receiving cavities for engaging mating terminals plugged into the upper terminal receiving cavities. The plurality of terminals also have contact portions below the circuit board that are disposed in the lower terminal receiving cavities for engaging mating terminals that are attached to the lower terminal receiving cavities. It is imperative that the contact portions below the circuit board be aligned with the center of their intended mating lower terminal receiving cavity. Alignment of the contact portions below the circuit board with the center of their intended mating lower terminal receiving cavity has typically been accomplished using the interface between the upper housing and the lower housing. However; prior to the upper housing, with the circuit board mounted therein, being attached to the lower housing, the circuit board may have some freedom to move laterally within the upper housing. This lateral movement of the circuit board within the upper housing may allow the contact portion of the terminals below the circuit board to be misaligned with respect to their intended mating lower terminal receiving cavity to a degree that does not allow the upper housing to be properly assembled to the lower housing. This misalignment may result in increased assembly time due to the need to manipulate the upper housing, lower housing, and/or circuit board to achieve proper alignment of the contact portions below the circuit board with the center of their intended mating lower terminal receiving cavity. This misalignment may also result in damage to one or more of the terminals if one or more of the contact portions of the terminals contact the lower housing, known as terminal stubbing, rather than each of the contact portions of the terminals below the circuit board being received within their intended mating lower terminal receiving cavity.

What is needed is an electrical distribution center and a method for assembling the electrical distribution center which minimizes or eliminates one or more of the shortcomings as set forth above.

SUMMARY OF THE INVENTION

Briefly described, an electrical distribution center is provided. The electrical distribution center includes an upper housing, a circuit board disposed in the upper housing, and a lower housing having a plurality of lower terminal receiving cavities and a plurality of alignment cavities. A plurality of terminals is mounted on the circuit board such that each terminal is in electrical communication with a respective electrically conductive member. The terminals have contact portions below the circuit board and disposed in the lower terminal receiving cavities such that each of the terminals extends from the circuit board no more than a first predetermined distance. A plurality of alignment posts are fixed to the circuit board and received within the alignment cavities such that each of the alignment posts extends from the circuit board at least a second predetermined distance which is greater than the first predetermined distance.

DETAILED DESCRIPTION OF INVENTION

Referring now toFIGS. 1-6wherein like reference numerals are used to identify identical components in the various views, an electrical distribution center10in accordance with the invention is shown which may be used, for example only, in a motor vehicle. Electrical distribution center10generally includes an upper housing12, a lower housing14, a circuit board assembly16disposed within upper housing12between upper housing12and lower housing14, and positive lock reinforcement members18,19,20,21. Electrical distribution center10may be disposed within a splash shield22and enclosed therein by a top cover24in order to protect electrical distribution center10from environmental hazards that may be encountered during the use of electrical distribution center10.

With continued reference toFIGS. 1-6, circuit board assembly16includes an electrically insulative circuit board26defining a plane onto which a plurality of two-way pass-through terminals28, a plurality of one-way terminals30, bus bar32, and one or more electronic devices34, for example only, relays and resistors, are mounted. A plurality of electrical traces35may be provided on circuit board26to connect two-way pass-through terminals28, one-way terminals30, bus bar32, and electronic devices34into various desired circuit patterns. Two-way pass-through terminals28have upper contact portions36above circuit board26and lower contact portions38below circuit board26. Some one-way terminals30include only upper contact portions36while other one-way terminals30include only lower contact portions38. Lower contact portions38extend from circuit board26no more than a first predetermined distance40. It should be noted that, for clarity, only one of each of two-way pass-through terminals28, one-way and one-way terminals, electrical devices, electrical traces35, upper contact portions36and lower contact portions38are labeled in the drawings.

Circuit board assembly16also includes a plurality of alignment posts42,44,46,48that extend from circuit board26in the same direction as lower contact portions38. Alignment posts42extend from circuit board26a second predetermined distance50such that second predetermined distance50is greater than first predetermined distance40. For example only, second predetermined distance50is about 5 mm greater than first predetermined distance40.

Alignment posts42,44, and46may be elongated in one direction, represented by arrow52, in the plane defined by circuit board26. Alignment post48may be elongated in another direction, represented by arrow54, in the plane defined by circuit board26such that direction54is substantially perpendicular to direction52. While alignment posts42,44,46are shown to all be elongated in the same direction, it should be understood that one or two of alignment posts42,44,46could be elongated in the same direction as alignment post48or in a third direction that is different from both direction52and direction54.

Alignment posts42,44,46,48are preferably made of a metallic material, and include one or more tabs56. Tabs56are closely received within alignment post receiving holes58in circuit board26in order to precisely locate alignment posts42,44,46,48on circuit board26. Alignment posts42,44,46,48are secured to circuit board26with a solder connection. Alignment posts42,44,46,48; together with the solder connection; rigidly retain alignment posts42,44,46,48to circuit board26. Alignment posts42,44,46,48are preferably located near the perimeter of circuit board26and are substantially perpendicular to the plane defined by circuit board26. While four alignment posts42,44,46,48are shown, it should be understood that a greater or lesser number may be provided.

Upper housing12may be made of an electrically insulative material, for example, plastic. Upper housing12may be made, for example, by a plastic injection molding process where plastic in liquid form is injected into a mold and allowed to solidify before being removed from the mold. Upper housing12includes a plurality of upper terminal receiving cavities60that extend through upper housing12. Upper contact portions36are disposed in upper terminal receiving cavities60for engaging mating terminals, shown as mating blades62of fuses64, plugged into upper terminal receiving cavities60. For instance, upper contact portions36may be a “tuning fork” design that receives mating blades62. However, other electrical devices such as relays (not shown) are commonly plugged into electrical centers and consequently, one or more of upper contact portions36may be of various designs to mate with other types of terminals associated with relays or other electrical or electronic devices that may be plugged into electrical distribution center10. It should be noted that, for clarity, only two upper terminal receiving cavities60are labeled in the drawings.

Upper housing12includes a circuit board compartment66extending along axis A which is substantially perpendicular to the plane defined by circuit board26. Circuit board assembly16is disposed within circuit board compartment66and is retained therein by circuit board retaining clips68which may be integrally formed as part of upper housing12. When circuit board assembly16is disposed within circuit board compartment66, but before upper housing12is attached to lower housing14, circuit board retaining clips68retain circuit board assembly16, but allow circuit board assembly16to move laterally, i.e. in the plane defined by circuit board26.

Lower housing14may be made of an electrically insulative material, for example, plastic. Lower housing14may be made, for example, by a plastic injection molding process where plastic in liquid form is injected into a mold and allowed to solidify before being removed from the mold. Lower housing14includes a plurality of lower terminal receiving cavities70that extend through lower housing14. Lower contact portions38are disposed in lower terminal receiving cavities70for engaging mating terminals72that are attached to wires74. Lower contact portions38are illustrated as blades and mating terminals72are illustrated as female terminals in the drawings; however, it should be understood that other types of lower contact portions and mating terminals may be used so long as the lower contact portions mate with the terminals attached to wires74when the terminals are plugged into lower terminal receiving cavities70. It should be noted that, for clarity, only two lower terminal receiving cavities70are labeled in the drawings.

Lower housing14also includes alignment cavities76,78,80,82for receiving alignment posts42,44,46,48respectively. Alignment cavities76,78,80,82are sized relative to alignment posts42,44,46,48to substantially prevent lateral movement, i.e. movement within the plane defined by circuit board26, of alignment posts42,44,46,48within respective alignment cavities76,78,80,82. Unlike lower terminal receiving cavities70, alignment cavities76,78,80,82do not receive a mating terminal because alignment posts42,44,46,48are used only for alignment purposes and are not involved with providing electrical communication.

Positive lock reinforcement members18,19,20,21are disposed between lower housing14and circuit board assembly16. Positive lock reinforcement members18,19,20,21have features which assist in retaining mating terminals72with lower terminal receiving cavities70.

Lower housing14may have features for receiving positive battery nut84and positive battery stud86which are each connected to bus bar32. Positive battery nut84may be used for connection to a battery (not shown) of a motor vehicle while positive battery stud86may be used for connection to an alternator (not shown) of the motor vehicle. Positive battery nut84may be in electrical communication with positive battery stud86, for example, by a portion of bus bar32.

Upper housing12may be positively retained to lower housing14with bolt88. The head of bolt88reacts against upper housing12while the threaded portion of bolt88is engaged with a mating threaded portion of lower housing14.

In assembling electrical distribution center10, circuit board assembly16is disposed within circuit board compartment66of upper housing12and retained therein by circuit board retaining clips68. Circuit board retaining clips68prevent circuit board assembly16from coming out of circuit board compartment66but allow lateral movement of circuit board assembly16within circuit board compartment66. Positive lock reinforcement members18,19,20,21are assembled to lower housing14. Next, upper housing12/circuit board assembly16and lower housing14/positive lock reinforcement members18,19,20,21are brought together in a direction that is substantially perpendicular to the plane defined by circuit board26. As upper housing12/circuit board assembly16and lower housing14/positive lock reinforcement members18,19,20,21are brought closer together, alignment posts42,44,46,48are aligned with their respectively alignment cavities76,78,80,82by allowing circuit board assembly16to move laterally within circuit bard compartment. After alignment posts42,44,46,48have been inserted part way into their respectively alignment cavities76,78,80,82; lower contact portions38are automatically aligned with their respective lower terminal receiving cavities70and lower contact portions38are inserted into their respective lower terminal receiving cavities70. Finally bolt88may be used to apply a force perpendicular to the plane defined by circuit board26in order to fully seat alignment posts42,44,46,48within their respectively alignment cavities76,78,80,82and lower contact portions38within their respective lower terminal receiving cavities70. In this way, alignment posts42,44,46,48together with alignment cavities76,78,80,82allow for easy alignment of lower contact portions38with their respective lower terminal receiving cavities70, thereby easing assembly of electrical distribution center10.

While this invention has been described in terms of preferred embodiments thereof, it is not intended to be so limited, but rather only to the extent set forth in the claims that follow.