System for connecting motor drives

A system for connecting motor drives to each other is disclosed that does not require the use of wire or tools. The system includes an adapter plug and bus bar modules that connect to each other at a conductive receptacle of the adapter plug to define a splice joint at the point of connect of the bus bar modules. The bus bar modules may include insulating covers and insulating clips may overlie the splice joints so that the system is substantially devoid of exposed surfaces of its conductive materials.

BACKGROUND OF THE INVENTION

The subject matter disclosed herein relates to electrical conductors that connect electronic components to each other and, more particularly, to wiring systems for connecting servo motor drives to each other within servo motor drive systems.

Servomotors provide a motor coupled to a sensor, for example, a position sensor such as an encoder, so that feedback control of the motor may be provided, for example, precise positioning control. Typically, a servo motor drive system provides a servo motor, for example, a DC permanent magnet motor and position encoder, which is wired to a servo drive. The servo drive provides a controllable source of DC power as controlled by a feedback signal from the position encoder by, for example, using a PID (proportional-integral-derivative) motor control algorithm.

The servo drive may be installed in an equipment cabinet to receive the source of DC power. When multiple servo drives are required, this source of DC power is independently wired to each of the servo drives, for example, using terminal blocks and/or standard electrical connectors with pins or blades engaging corresponding sockets. Power has been delivered to printed circuit boards through bus bars that engage connectors that are soldered or screwed to the printed circuit boards.

BRIEF DESCRIPTION OF THE INVENTION

The inventors have recognized that wiring electronic components such as, for example, motor drives to each other can take substantial amounts of time. The inventors have also recognized that different end-use implementations of industrial controls may require highly skilled technicians to assemble motor drives because such end-use implementations tend to differ from each other and may require, for example, using numerous conductors that have to be cut to length to make numerous wire-based “daisy-chain”-type or other sequential connections to interconnect the motor drives. The inventors have further recognized that bus bar based connecting systems typically include bus bar receptacles that have to be soldered or screwed to printed circuit boards, which may take substantial amounts of time to install. The inventors have yet further recognized that the bus bars of such connecting systems present exposed conductive surfaces having relatively large surface areas and that are in locations of motor drive housings that may be subjected to airborne particulate matter which may dirty the electrical contacts and compromise conductivity, and that bus bars of such connecting systems may also be in locations of motor drives housings that may be accessed later by technicians with tools, which may inadvertently produce short circuit conditions by contacting the exposed bus bars. The present invention contemplates a bus bar connector system that addresses various ones of these and other inventor-identified problems and drawbacks of known systems.

In accordance with an aspect of the invention, a bus bar connector system is provided for removably connecting at least two electronic components to each other. The system may include a bus bar module having a bus bar with a first blade having a first exposed conductive surface(s) for connecting to a first electronic component and a second blade having a second exposed conductive surface(s) for connecting to a second electronic component. The bus bar may have a covered segment that extends between the first and second blades. An insulating cover may be connected to the bus bar and extend over the covered segment of the bus bar. A clip may engage the bus bar module and be movable between at least first and second positions. When the clip is in the first position, it may overlie at least one of the first and second blades or exposed conductive surfaces of the bus bar. When the clip is in the second position, it may be spaced from the first and/or second blades or exposed conductive surfaces of the bus bar. This may allow conductors within the bus bar connector system to be covered or non-exposed.

In accordance with another aspect of the invention, the insulating cover may include a pair of opposing side walls that extend over a pair of opposing side walls of the bus bar module. The clip side walls may slidingly engage the insulating cover side walls so that the clip can move longitudinally with respect to the bus bar module while being transversely guided upon the bus bar module. This may allow conductors within the bus bar connector system to be covered quickly during assembly.

In accordance with another aspect of the invention, the bus bar connector system includes first and second bus bar modules. The first and second bus bar modules may be connected to each other at a splice joint. The splice joint may include a conductive receptacle that holds respective ends of the first and second bus bar modules, so that their blades or exposed conductive surfaces contact the conductive receptacle so as to electrically connect the first and second bus bar modules to each other. The clip may cover the splice joint so that the covered surfaces of the bus bars of the first and second bus bar modules and the clip define a continuously covered length of the combination of the first and second bus bar modules and splice joint. This may allow bus bars to be quickly coupled to or uncoupled from each other which may facilitate connecting electronic components to each other while providing a connector system that has its conductive surfaces substantially covered with insulating materials.

In accordance with another aspect of the invention, the conductive receptacle may be provided in a plug housing of an adapter plug. The conductive receptacle may be provided at a first end of the adapter plug and a second end of the adapter plug may be operably coupled to a connector that is fixed to a printed circuit board of an electronic device. This may facilitate quickly connecting electronic devices to each other.

In accordance with another aspect of the invention, the clip may be slidably mounted to the first bus bar module and may be slidable over the plug housing and upon the second bus bar module, so that the clip covers the entire splice joint and overlaps portions of the first and second bus bar modules. A lock may be provided that prevents sliding movement of the clip with respect to the splice joint. The lock may include a lock projection and a cooperating lock receptacle on the clip and at least one of the adapter plug and first and second bus bar modules, which can engage each other to secure the clip in place when it covers the splice joint. This may allow the clip to remain in a position in which it covers the splice joint that connects bus bars to each other so that conductive materials of the splice joint remain unexposed or substantially covered with insulating materials.

In accordance with another aspect of the invention, each bus bar module may include a pair of bus bars that are transversely spaced and electrically insulated from each other. Each adapter plug may include a pair of connective receptacles that are transversely spaced from and insulated with respect to each other. This may facilitate simultaneously connecting positive and negative bus bars to electronic components which may simplify connecting such electronic components to each other by allowing multiple connections to be made in a single installation step.

In accordance with another aspect of the invention, the bus bar connector system may be implemented within an industrial control system and may connect multiple motor drives to each other. First, second, and third adapter plugs may be connected to first, second, and third motor drives of the industrial control system. A pair of bus bar modules may be longitudinally aligned with each other so that outer ends of the bus bar modules are connected to the first and third adapter plugs. Inner or inwardly positioned ends of the bus bar modules may be connected to each other at a spliced joint defined at the second adapter plug and a clip may extend over the splice joint. The bus bar connector system may include the same number of adapter plugs as the number of motor drives that are being connected and may include one fewer bus bar module than the number of motor drives and adapter plugs. This may facilitate connecting multiple motor drives to each other in a tool-less manner.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring now toFIGS. 1 and 2, a bus bar connector system30is a modular system that electronically connects at least two, while allowing for connecting an arbitrary number of, electronic components to each other in a tool-less manner. The bus bar connector system30is described as being used in a servo motor drive system10to simplify its explanation, while noting that the bus bar connector system30in other embodiments may be implemented to interconnect various other electronic components to each other.

Still referring toFIGS. 1 and 2, a servo motor drive system10may provide for multiple drive modules12a-12ceach having generally rectangular housings14that may be mounted in a control cabinet or the like to be in side-by-side adjacent relationship with respect to each other. Rear vertical walls16of the housings14may include openings through which connectors18are accessible and to which power conductors20and signal conductors22may be connected. Power conductors20may deliver electrical power to windings of a servomotor25for energizing the servomotor. Signal conductors22may convey control signals between an encoder of the servomotor25and the drive modules12a-12cso that the drive modules12a-12cmay control the servomotor22according to methods well known in the art.

Still referring toFIGS. 1 and 2, horizontal upper walls26of the drive modules housings14of this embodiment may present socket receptacles28of electrical connectors27that are flush mounted with the upper walls26of the drive modules12a-12c.The electrical connectors27are operably connected to printed circuit boards of the drive modules12a-12cfor delivering electrical power to the drive modules12a-12c.

Still referring toFIGS. 1 and 2, a bus bar connector system30is a modular system that interconnects the drive modules12a-12cby wire-free daisy chain connections that can provide main power and/or control power to the drive modules12a-12c. In one embodiment, the main power is 100 amp DC bus power and the control power is 16 amp, 24 volt control power, optionally, other values of main and control power, depending on the particular configurations of the drive modules12a-12c. The modular configuration of the bus bar connector system30allows for drive modules12a-12cto be added to or removed from the servo motor drive system10, while making or removing the electrical interconnections between the drive modules12a-12cin a tool-less manner.

Still referring toFIGS. 1 and 2, the bus bar connector system30includes adapter plugs40,41and bus bar modules70,71that cooperate with each other to make the tool-less electrical connections between the drive modules12a-12c. Multiple adapter plugs40,41and multiple bus bar modules70,71may be provided within the bus bar connector system30so that an arbitrary number of parallel electrical conductive paths through chains of the bus bar modules70,71in a manner that allows an arbitrary number of drive modules12a-12cto be electrically connected to each other.

Referring now toFIG. 3, adapter plug40has a plug leg42at a first end of the adapter plug40and that is made from a polymeric or other electrically insulating material. The plug leg42can be inserted, by hand, into the socket receptacle28of the electrical connector27of the printed circuit board of the drive module12a-12c. When the plug leg42is inserted into the socket receptacle28, a conductive pin43that extends longitudinally through the plug leg42couples to a cooperating conductor (not shown) within the socket receptacle28. In this way, the adapter plug40and the electrical connector27are mechanically and electrically connected to each other.

Still referring toFIG. 3, at a second end of the adapter plug40, a plug housing50that holds a conductive receptacle60is connected to an end of the plug leg42. The plug housing50is made from a polymeric or other electrically insulating material and includes a bottom wall51that extends transversely with respect to and outwardly beyond the plug leg42. A pair of side walls55extends upwardly from outer edges of the bottom wall51, providing the plug housing50with a U-shaped configuration with openings at the top, front, and back. The conductive receptacle60is nested within the adapter plug40and is operably connected to the conductive pin43so that an electrically conductive path is defined through the conductive receptacle and pin60,43. The conductive receptacle60has a pair of opposing leaves62that are interconnected through a base strap66. Each of the leaves62includes an intermediate segment63that extends between bent upper and lower ends64,65that extend angularly from the intermediate segment.

Still referring toFIG. 3, at surfaces of the leaves62that face outwardly or toward the plug housing side walls55, obtuse angles are defined at points of intersection between the bent upper and lower ends and the intermediate segment. Acute angles are defined at inwardly facing surfaces of the bent lower ends65of the leaves62and an upwardly facing surface of the base conductive receptacle base strap66. A generally rectangular slot68is defined between the leaves62and base strap66and is configured to receive the bus bar module(s)70so that it is resiliently held between the leaves62of the conductive receptacle60.

Referring now toFIG. 4, adapter plug41of this embodiment is largely analogous to adapter plug40ofFIG. 3, described above, only being configured as a unitized pair of adapter plugs. Accordingly, many of the parts of adapter plug40that are also in adapter plug41are not described here again with respect to adapter plug41because their descriptions above with respect to adapter plug40are also applicable here with respect to adapter plug41.

Still referring toFIG. 4, adapter plug41includes a pair of plug legs42that extend downwardly from a plug housing50that holds a pair of conductive receptacles60. The plug legs42are spaced from each other by a distance that corresponds to a distance between a pair of receptacles28of the electrical connectors27of the drive module12a-12c.The electrical connectors27of the drive module12a-12cmay be positive and negative polarity connectors of the DC bus power system for the drive module12a-12c.This may allow the adapter plug41to connect to both positive and negative polarity connectors of the DC bus power system and/or control power to the drive modules12a-12cin a single installation step.

Still referring toFIG. 4, in this embodiment, the bottom wall51of adapter plug41defines a first segment52between one plug leg42and conductive receptacle60and a second segment53between a second plug leg42and corresponding conductive receptacle60. An intermediate wall58extends from a point of intersection of the first and second bottom wall segments52,53of the bottom wall51. The intermediate wall58extends parallel to and is arranged between the side walls55and extends further away from the bottom wall51than the side walls55. In this configuration, the intermediate wall58can support a middle portion of a clip100from below when the clip100is mounted over the plug housing50, explained in greater detail elsewhere herein. The pair of conductive receptacles60is provided on opposing sides of the intermediate wall58so that intermediate wall58defines an insulating barrier between the pair of conductive receptacles60that receive and resiliently hold the bus bar module71, similar to how the adapter plug40resiliently holds the bus bar module70, as described in greater detail elsewhere herein.

Referring now toFIGS. 1 and 5, bus bar module70includes a bus bar72that is made from an electrically conductive metallic material and a cover80that is made from a polymeric or other insulating material. A clip100that is made from a polymeric or other insulating material is provided that engages the bus bar modules70and/or adapter plug40to selectively cover various surfaces of conductive materials, as described in greater detail elsewhere herein.

Still referring toFIGS. 1 and 5, bus bar72includes blades73,74at opposing ends and a covered segment75that extends between and connects the blades73,74to each other. In this embodiment, the blades73,74and covered segment75are integral with each other so that a single piece of conductive material defines the bus bar72. As shown inFIG. 1, in this embodiment, the covered segment75is covered on an upper wall76and on most of a pair of side walls78of the bus bar72. A lower wall77and lower portions of the covered segment75, for example, the lowermost 20 percent of a height of the covered segment75, is exposed and facing toward the drive modules12a-12c.

Referring now toFIG. 5, cover80includes a lower wall81and a pair of side walls82that extend downwardly from outer perimeter edges of the lower wall81. In this embodiment, the side walls82include alternating ribs83and grooves84that define gripping surfaces85on the cover80that can be grasped by fingers of a user and that may facilitate tool-less insertion and removal of the bus bar module70into and from the adapter plug40. A lower wall87extends between lower edges of the side walls and channel88extends upwardly through lower wall87toward the upper wall91.

The channel88extends longitudinally through the entire cover80and is configured to receive the bus bar72so that the cover engages and overlies the covered segment75of the bus bar72. In one embodiment, cover80is press or friction fit to the bus bar72. In one embodiment, the cover80is adhered or bonded to the bus bar72with suitable adhesive and/or bonding agents, well known to those skilled in the art. In another embodiment, the cover80extends around the entire perimeter of the bus bar72at the covered segment75, so that the blades73,74are the only exposed conductive surfaces of the bus bar72. This can be seen inFIG. 5as the cover80and phantom outline extension that continues around the lower wall77of the bus bar72. In such embodiment, the cover80can include upper and lower segments, or other cooperating segments, segments that snap-fit with each other to completely surround the covered segment75of the bus bar72. Or, the cover80and/or cover components can be implemented as a single unitary piece that is applied to the bus bar72in an overmolding procedure.

Referring now toFIG. 6, bus bar module71of this embodiment is largely analogous to bus bar module70ofFIG. 5, described above, only being configured as including a pair of bus bars72. Accordingly, many of the parts of bus bar module70that are also in bus bar module71are not described here again with respect to bus bar module71because their descriptions above with respect to bus bar module70are also applicable here with respect to adapter plug71.

Still referring toFIG. 6, bus bar module71includes a pair of bus bars72and a cover80. Cover80of this embodiment includes first and second segments90,92that hold the pair of bus bars72. The first and second segments90,92are defined on opposing sides of a longitudinally extending centerline of the cover80. A pair of intermediate walls94,96that are spaced from each other extends from the lower wall81and are parallel to and are positioned between the side walls82. An opening89extends through the upper wall91, between the intermediate walls94,96so that a pair of arms93are defined at opposing ends of the upper wall91that connect the first and second segments90,92to each other.

Still referring toFIG. 6, a pair of channels88is defined between (i) the intermediate wall94and an adjacent side wall82, and (ii) the intermediate wall96and the other side wall82. The pair of bus bars72is mounted in the pair of channels88by press or friction fit, adhesion, bonding, or overmolding so that each of the first and second segments90,92extends over a majority or an entirety of the covered segment75of the respective bus bar72.

Referring again toFIGS. 1 and 2, a chain(s) of bus bar modules70,71that interconnects the drive modules12a-12cis defined by multiple bus bar modules70,71that are longitudinally aligned and electrically connected to each other at a splice joint150. The splice joint150includes the adjacent blades73,74of an aligned pair of adjacent bus bars72that are both held between the leaves62of the conductive receptacle(s)60of the adapter plug40,41. In the splice joint150, each of the blades73,74extends about halfway along the length of the slot68. End surface of the covers80of the bus bar modules70,71that face each other can abut corresponding end surfaces at opposing sides of the plug housing50which may help secure the bus bar modules70,71in a longitudinal direction within the adapter plugs40,41.

Referring now toFIGS. 5 and 6, clip100is made from a polymeric or other electrically insulating material and includes an upper wall102and a pair of side walls104that extends downwardly from opposing side edges of the upper wall102. As shown inFIGS. 1 and 2, the clip100is long enough so that once the clip100is installed over the splice joint150, it extends entirely over the blades73,74and over parts of the covers80of the adjacent bus bar modules70,71that are connected to each other at the splice joint150. A distance between the clip side walls104corresponds to a width of the adapter plug housing50and bus bar cover80. This provides the clip100with an upside-down U-shape configuration that can fit over the adapter plug40,41and/or bus bar modules70,71for selectively covering the splice joint(s) (FIGS. 1 and 2) by either vertically inserting the clip100from above the splice joint150or by sliding the clip100horizontally across the splice joint150. When the clip100is slid over across the splice joint150, the plug housing50and bus bar covers80that nest inside and slide within the clip100guide the travel of the clip100as it travels across the splice joint150. In one embodiment, bottom portions of the clip side walls104include lips or rails (not shown) that extend inwardly toward each other, across the clip100and such lips or rails engage the lower walls87of the bus bar cover80and plug housing bottom wall51of the adapter plug40,41while the clip100slides thereupon.

Referring again toFIGS. 1 and 2, a lock200includes a lock receptacle210that extends into inwardly facing surfaces of the clip side walls104and lock projections220that extend outwardly from the bus bar cover side walls82. The lock projections220include ramped surfaces222that slant toward the side walls82and so that when the clip100is slid across to cover the splice joint150, the clip side walls104are deflected outwardly from each other until the lock receptacle210overlies the lock projection220, at which point the clip side walls104restore inwardly and the lock projection220is held within the lock receptacle210. In one embodiment, the lock receptacles210extend into the bus bar side walls82and the lock projections220extend into the clip side walls104. In another embodiment, one bus bar side wall82has a lock receptacle210and the second bus bar side wall82has a lock projection220, whereas the corresponding clip side walls104have the other ones of the lock receptacle and projections210,220.

In light of the above, using the bus bar connector system30allows a user to electrically interconnect multiple drive modules12a-12c, without using wires or tools. The adapter plugs40,41are pressed into the electrical connectors27that are attached to the printed circuit boards of the drive modules12a-12c. The bus bar modules70,71are then pressed into the adapter plugs40,41, so that the blades73,74of the bus bars72are squeezed between the leaves62of the conductive receptacles60. This connects the blades73,74that are being held within a common conductive receptacle60to each other, at a splice joint150. The splice joint150is encapsulated between the adapter plug housing50and a clip100by locking the clip100over the splice joint150. This may be done by, for example, pushing the clip100over the adapter plug housing50, vertically from above. Or the clip100may be pushed onto a first cover80of a first bus bar module70,71. The clip100is slid over the splice joint150so that the lock receptacles210of the clip side walls104engage lock projections220of bus bar cover side walls82of a second cover80of a second bus bar module70,71that is being joined to the first bus bar module70,71through the splice joint150. This is repeated as many times as necessary to connect the desired number of drive modules12a-12cor other electronic components to each other. Such procedures may be performed in a reverse order to disconnect the modules12a-12cor other electronic components from each other in a tool-less manner. This provides an easy to assemble and disassemble chain of spliced-together bus bars72with substantially no exposed electrically conductive materials or surfaces, for example, more than about 70 percent and preferably more that about 80 percent of the electrically conductive materials of the bus bar connector system30being covered by the insulating materials of the covers80, plug housing50, and clips100.