WO2004070886A1

WO2004070886A1 - Connector

Info

Publication number: WO2004070886A1
Application number: PCT/US2004/002839
Authority: WO
Inventors: Naoya Matsuura; Kotaro Kobayashi; Hiroshi Ikesugi
Original assignee: Molex Incorporated
Priority date: 2003-01-31
Filing date: 2004-01-30
Publication date: 2004-08-19
Also published as: JP4116456B2; GB2413714B; JP2004235081A; GB2413714A; GB0516535D0

Abstract

A connector (1) is mounted onto electrical equipment (10) to supply/transmit electrical signals to the electrical equipment (10) and it includes an insulated housing (11), signal terminals for connecting to an opposing connector, a ground terminal (12) for connecting to a grounding terminal of the opposing connector, and a conductive pedestal portion (21) that is fastened together with the insulated housing (11) by conductive fasteners that also mount the connector to the apparatus. The ground terminal (12) and the pedestal portion (21) are electrically connected to each other by being formed integrally or separately with respect to each other.

Description

CONNECTOR

Background of the Invention

The present invention relates generally to grounding com ectors, and more particularly to connectors used to ground the frame of an electrical apparatus such as motors or the like.

Making an electric apparatus and other parts of it be equal in an electric potential is often extremely important for precise operation of the apparatus. For example, in servo motors or encoder-related equipment, in addition to grounding the control apparatus (servo amplifier) such as a PLC, it is also necessary to provide grounding separately for the main body of the motor. Failure to provide sufficient grounding for those may result in a motor rotation error or a malfunction. Some motors produce high-frequency noise during operation, depending on their internal structures, and it is known that grounding serves as an effective counter-measure therefor.

FIG. 12 of the drawings is an exploded view that illustrates a conventional connector 301 that provides such a grounding function. The comiector 301 has an insulated housing 311 which supports a ground terminal 312, and a housing cover 320 is fit over the exterior of the housing 311. The housing cover 320 is formed of a conductive material, such as a metal and may be typically die cast. The housing 311 is fixed in the housing cover 320 with screws 314, and the ground terminal 312 that is assembled onto the housing 311 is electrically connected to the housing cover 320. In the connector 301, the housing cover 320 is fixed with screws 322 to an exterior frame 313 of the electrical apparatus, such as a servo motor so that ground terminal 312 is electrically connected to the frame 313 through the cover 320.

If noise is induced on a signal line system from the servo amplifier, or if noise is generated in the motor itself, the noise is first transmitted from the frame 313 of the motor to the housing cover 320 and then to a mating connector through the ground terminal 312, and finally discharged to ground by way of a ground wire.

Other than connectors of the type described above, there are also connectors in which the ground terminal is dispensed with by forming the housing from a conductive material. In such connectors, as well as in the above-mentioned connector 301, the housing is fixed to the frame of electrical equipment or the like through the housing cover.

Another known connector apparatus 401 is shown in FIG. 13, in which a metallic coating film 420 is formed by vacuum evaporation of aluminum or by way of metal plating or the like on the outer surface of an insulated housing 411 in which an electrical connector 412 is held inside thereof as is described in Japanese Utility Model Application Laid-open No. Hei 4-8375. In the connector apparatus 401 shown in FIG 13, the connector housing 411 is fixed to a printed circuit board 413 using conductive fasteners, such as bolts 414 and nuts 415. Thus, the metallic coating film 420 on the exterior of the housing 411 is electrically connected to a grounding portion of the printed circuit board 413 by way of the fasteners 414, 415.

However, there is a problem with the conventional connector 301 of FIG. 12 in that it requires the housing cover 320, the ground terminal 312 and the insulated housing 311 to be formed as separate parts. The number of parts and the number of assembly steps in this type of connector are increased, resulting in increases in cost and size of the connector.

In the case of the conventional connector 401 of FIG. 13, the use of the metallic film 420 formed on the outer surface of the connector housing 411 allows sufficient conduction to be established between the connector apparatus 401 and the circuit board 413. However, grounding cannot be achieved unless a similar exterior coating is applied to the mating connector that fits with the connector apparatus 401. Accordingly, with respect to the mating connector, the metallic film needs to be applied onto the inner surfaces of the mating connector and brought into contact with the outer surfaces of the connector apparatus 401, and also short-circuiting between terminals arranged inside the mating connector must be prevented. This adds difficulty to the assembly and the number of steps associated with the assembly of such connectors are further increased as compared with those required for the outer peripheral surface, with a result that the processings to be performed on both of the connectors lead to an increase in cost.

The present invention has been made in view of the above-mentioned problems, and therefore an object of the invention is to provide a connector which is capable of reliably removing noise that is generated in a mating connector and in which the number of parts, processing steps, and assembly steps can be reduced to achieve reductions in cost and size of the connector. Summary of the Invention

Accordingly, it is a general object of the presnet invention to provide an improved grounding comiector for providing a grounded signal connection for a plurality of signal terminals while providing a connection to an external ground connection for an electrical apparatus.

This is accomplished by way of the structure of the present invention in which the connectors of the invention include an insulated housing; a plurality of signal terminals supported by the connector housing for connecting to a corresponding plurality of signal terminals of an opposing mating connector; and a ground terminal that is supported by the connector housing for connecting to a ground terminal of the mating connector.

The connector has a conductive pedestal portion which is fastened together with the insulated housing by screws or the like at a mounting part of the connector housing. The ground terminal and the pedestal portion are electrically connected to each other by either formed integrally together or separately and connected together. A ground wire from a frame ground of an electrical apparatus may be reliably secured through the connector, so that various failures due to electrical noise may be reliably suppressed.

There is no need to supply the connectors of the invention with a housing cover, thereby allowing a reduction in the number of parts needed as well as in the number of assembly steps. There is no need to form a metallic coating on the outer surfaces of the connector housing, and therefore the number of processing steps to assemble such connectors may be reduced. Thus, it is possible to achieve reductions in cost and size.

The ground terminal may be locked at the mounting part of the connector housing by the pedestal portion sandwiching an upper surface and a lower surface of the mounting part to effectively prevent the ground terminal from becoming dislodged from the connector housing. The connection between the ground terminal and the pedestal portion may includes a bent connecting part. As a result, the mounting can be located closer in the interior of the connector housing than the ground terminal which allows a further reduction in the size of the connector housing. This is because although it is necessary to locate the ground terminal at a predetermined position in relation to the opposing mating connector, the position of the mounting part may be located freely, so that the position of a hole that mates with the mounting part may also be set freely.

However, due to considerations related to the processing and the mechanical strength of the connector components, it is necessary to provide a predetermined spacing between the end face of the connector housing, which extends along the bent connecting and the mounting part part, and the portion where the bent connecting part is located, as well as between the end face and the hole where the mounting fixing part is located. In this case, when the center of the hole is located on the inner side than the bent connecting part, the spacing between the end face of the connector housing and the bent connecting part may be set to a minimum distance, with little consideration on the spacing between the connector housing and the hole. Therefore, it is possible to further reduce the size of the connector housing.

These and other objects, features and advantages of the present invention will be clearly understood through a consideration of the following detailed description.

Brief Description Of The Drawings

In the course of this detailed description, the reference will be frequently made to the attached drawings in which:

FIG. 1 is a general perspective view of a connector, showing an embodiment mode of the present invention;

FIG. 2 is a cross-sectional view taken along the line A- A of FIG. 1;

FIG. 3 is a cross-sectional view taken along the line B-B of FIG. 1, which is an exploded view showing an insulated housing of the present invention and an inner housing received therein;

FIG. 4 is a front view showing a state before mounting of a ground terminal of the present invention;

FIG. 5 is a view as seen from the direction of arrow C in FIG. 4.

FIG. 6 is a cross-sectional view corresponding to FIG. 2, showing a state where the ground terminal is inserted from the bottom portion of the insulated housing; FIG. 7 is an enlarged cross-sectional view taken along the line D-D of FIG.6, showing how the inserted ground terminal is fixed to the insulated housing;

FIG. 8 is a plan view of the connector of the present invention, showing a fitting surface;

FIG. 9 is an enlarged view of a cross section taken along the line of F-F of FIG. 2, showing an offset position of the ground terminal;

FIG.10 is a view showing a grounding path of the present invention;

FIG. 11 A is a top view showing a case in which the center of a hole according to the present invention is located closer to the inner side of the insulated housing than a first contact portion;

FIG. 1 IB is a top view showing a case in which a spacing between the center of the hole and an end face and a spacing between the first contact portion and the end face are set to be the same;

FIG. 12 is a cross-sectional view showing a conventional example; and,

FIG. 13 is a perspective view showing another conventional example. Detailed Description Of The Preferred Embodiments

One embodiment of the present invention is shown in FIGS. 1 to 11 and includes a connector 1 for transmitting signals to a servo motor 10 to which the connector is mounted. The connector 1 is seen to include an insulated housing 11, signal terminal ground terminals 12 incorporated into the insulated housing 11, and one or more screws 14 (FIG. 2) that serve to mount the housing 11 to a frame 13 of the apparatus to which the connector 1 is to be mounted.

The screw 14 is conductive and the apparatus frame 13 functions as a grounding portion. The screw 14 contacts one of the ground terminals 12 and the frame 13 of the servo motor, so that the ground terminal 12 and the frame 13 are electrically connected to each other through the screw 14 to define a grounding path through the connector. The screw 14 is brought into direct contact with the ground terminal 12 as explained in detail below.

As shown in FIGS. 1 & 3, the housing 11 includes a housing main body portion 15 and an inner housing 16 that is inserted into the main body portion 15. The housing 11 has a seat portion 17 through which the screw 14 extends and against which, the screw 14 is seated. The seat portion 17 includes a mounting hole 18 that serves as a mounting part through which the screw 14 is inserted. Two grooves 18a and 18a are formed on an inner peripheral surface of the mounting hole 18 (FIG. 9) and these grooves 18a and 18a are formed so as to be positioned substantially 180 degrees apart from each other. A screw hole 19 that receives the screw 14 is formed in the frame 13 of the servo motor 10. The screw 14 and the frame 13 are electrically connected together when the screw 14 is threaded into the screw hole 19.

As shown best in FIGS. 4 & 5, the ground terminal 12 includes a first contact portion 20 that extends into a cavity of the connector housing to make contact with a mating connector (not shown); a second contact portion 21 that serves as a pedestal portion that located around at least a portion of the edge of the mounting hole 18 formed in the seat portion 17 (FIG. 2), as well as within the grooves 18a and 18a; and, a bent connecting part 22 that connects the first contact portion 20 to the second contact portion 21.

The first contact portion 20, the second contact portion 21, and the bent connecting part 22 are preferably integrally foraied from a conductive material in order to facilitate the assembly thereof onto the housing 11. In the ground terminal 12, the first contact portion 20 is formed in the form of a thin, elongate plate which extends upward from one end of the bent connecting part 22. Formed in a substantially central portion of the first contact portion 20 is a notch 20a that extends in the longitudinal direction. Prior to bending, the second contact portion 21 is formed in the form of a substantially oblong ring and extends vertically from the other end of the bent connecting part 22 substantially in parallel to the first contact portion 20. Once bent (FIGS. 4 &5) the second contact portion 21 has a lower arcuate portion 21a extending in a direction (downward) opposite to the first contact portion 20, an upper arcuate portion 21b projecting in the same direction (upward) as the first contact portion 20, and intermediate portions 21c formed between the lower arcuate portion 21a and the upper arcuate portion 21b. The lower arcuate portion 21a extends in a direction opposite to the first contact portion 20 and is bent at a substantially right angle with respect to the intermediate portions 21c.

The second contact portion 21 and the bent connecting part 22 are formed so as to cross each other at a predetermined angle α. In the present example, the angle a is set to be approximately 45 degrees. Note that, as will be described later, after the ground terminal 12 is assembled onto the insulated housing 11, the above-described upper arcuate portion 21b is bent about its radius portion in the same direction as the lower arcuate portion 21a (FIG. 7)

When assembling the ground terminal 12 into the housing 11, the ground terminal 12 is inserted from the bottom surface side of the housing into the mounting hole 18 (and grooves 18a & 11 a in FIG. 9) provided in the housing 11. Accordingly, as shown in FIG. 6, the first contact portion 20 of the ground terminal 12 is located in the internal space of the insulated housing 11. Further, the intermediate portions 21c of the second contact portion 21 are inserted into the grooves 18a and 18a formed in the inner peripheral surface of the mounting hole 18 provided in the seat portion 17 of the insulated housing 11.

Then, the lower arcuate portion 21a of the second contact portion 21 is located around the opening edge of the mounting hole 18 such that the entirety thereof abuts against the bottom surface of the seat portion 17. Further, the upper arcuate portion 21b of the second contact ^• portion 21 is located so as to project outward from the mounting hole 18. Next, as shown in FIG. 7, the lower portion 21a is held with a punch or a jig 26, and the upper arcuate portion 21b on the side opposite therefrom is bent about its radius portion at a substantially right angle and in the same direction as the lower arcuate portion 21a. Then, the entirety of the upper arcuate portion 21b is brought to abut against the surface of the seat portion 17.

In the present example, a counterbore 27 of a substantially semicircular shape is formed in the top surface of the seat portion 17 (FIG. 7) so as to have a depth equal to the board thickness of the ground terminal 12, and the upper arcuate portion 21b of the ground terminal 12 is inserted into the counter bore 27. As shown in FIG. 8, the lower arcuate portion 21a and the upper arcuate portion 21b are provided on both ends of the second contact portion 21 and are located substantially halfway along the opening edge of the mounting hole 18 while abutting the upper and lower surfaces of the seat portion 17, respectively.

When mounting the connector 1 to the apparatus, the upper arcuate portion 21b of the second contact portion 21 is fastened and fixed between a head portion 14a of the screw 14 and the seat portion 17 of the insulated housing 11 , as shown best in FIG.1. The intermediate portions 21c and 21c of the second contact portion 21 are held in place while inserted into the grooves 18a and 18a formed in the inner peripheral surface of the mounting hole 18. Note that, the bent connecting part 22 is also located within the groove 11a (FIG. 9) formed inside the insulated housing 11. As shown in FIG. 9, a center 18b of the mounting hole 18 through which the screw 14 extends is located at a position more distant than that of the first contact portion 20, as seen from an end face 30 of the insulated housing 11, which serves as a reference plane.

In the connector 1, as shown best in FIG.10, the ground terminal 12 and the frame 13 that serves as the apparatus ground are electrically connected to each other through the screw 14 that mounts the housing 11 to the servo motor frame 13. The ground terminal 12, the screw 14, and the frame 13 all cooperatively together form a grounding path 31. As a result, noise or the like generated in electrical equipment that will be connected to the connector 1 or in the wires of the mating connector will be reliably removed via the grounding path 31. Since the housing cover 320 that used in the conventional connector 301, shown in FIG. 12, can be eliminated, the number of parts and the number of assembly steps are reduced, thereby allowing reductions in both cost and size of the connector.

The ground terminal 12 and the frame 13 are electrically connected to each other through the screw 14, a common item, so there is no need to form a metallic coating on the housing as is the case with the conventional connector 401 of FIG. 13. The ground terminal 12 maybe foπned now extremely small in size. Accordingly, the number of processing steps and the materials cost are reduced to allow a reduction in cost.

The upper arcuate portion 21b of the second contact portion 21 of the ground terminal 12 is located around the opening edge of the mounting hole 18, and the upper arcuate portion 21b is sandwiched between the head portion 14a of the screw 14 and the seat portion 17 of the insulated housing 11, so that a secure electrical connection is provided between the screw 14 and the ground terminal 12. Further, as shown in FIG. 9, in relation to the end face 30 of the insulated housing 11 , the center 18b of the mounting hole 18 where the second contact portion 21 of the ground terminal 12 is to be located is located on the inner side than the portion where the first contact portion 20 is to be located, thereby making it possible to further reduce the size of the insulated housing 11 as described below.

As shown in FIG. 11 A, while it is difficult to change the position of the first contact portion 20 as that position is determined by the fitting arrangement with respect to the mating connector, the position of the mounting hole 18 may be set relatively freely within the connector housing. It is desirable to provide a spacing of a predetermined value or larger between the end face 30 and the portion where the first contact portion 20 is located, as well as between the end face 30 and the mounting hole 18. In this case, when the center 18b of the mounting hole 18 is located closer to the inner side of the insulated housing 11 than the portion where the first contact portion 20 is located, the spacing between the portion where the first contact portion 20 is located and the end face 30 may be set to a minimum necessary dimension without regard to the spacing between the mounting hole 18 and the end face 30. Therefore, it is possible to further reduce the size of the insulated housing 11.

In contrast, when as shown in FIG. 1 IB, the spacing between the center 18b of the mounting hole 18 and the end face 30 and the spacing between the first contact portion 20 and the end face 30 are of the same dimension, and because the diameter size of the mounting hole 18 is relatively large, it is necessary to set the position of the end face 30 such that the spacing between the end face 30 and the mounting hole 18 becomes larger than a predetermined value. In this case, even if the spacing between the end face 30 and the mounting hole 18 is set to be a minimum necessary dimension, the spacing between the first contact portion 20 and the end face 30 becomes large as compared with the case where the center 18b of the mounting hole 18 is located on the imier side than the first contact portion 20 as described above.

That is, when a comparison is made between the case where the center 18b of the mounting hole 18 is located closer to the inner side of the insulated housing 11 than the first contact portion 20 (FIG. 11A) and the case where the center 18b of the mounting hole 18 and the first contact portion 20 are located at substantially the same distance from the end face 30 (FIG. 1 IB), the dimension LI of the connector 1 in the former case becomes smaller than the dimension L2 of the connector 1 in the latter case.

It is also possible to locate the center 18b of the mounting hole 18 and the first contact portion 20 at the same distance from the end face 30, or to locate the mounting hole center 18b closer to the outer side of the housing than the first contact portion 20. Furthermore, although the screw 14 is used as fixing means in the above-described embodiment mode, a variety of things may be used as the fixing means other than the screw 14. In that case, the second contact portion 21 of the ground terminal 12 must be of a configuration that allows it to contact the fixing means.

Further, although the foregoing description of the embodiment mode is directed to the case where the connector 1 is mounted to the frame 13 of the servo motor 10, the connector 1 of the present invention can be mounted to a variety of electrical equipment. The ground terminal is assembled onto the housing and the grounding portion of the apparatus to which the connector is mounted are electrically connected together through the conductive mounting screws. As a result, the cover used in conventional connectors may be eliminated, and also there is no need to form a metallic coating on the outer surface of the housing. Consequently, noise induced in electrical equipment and the connection part thereof can be reliably removed, and also the number of parts, processing steps, and assembly steps can be reduced, whereby it is possible to achieve reductions in cost and size.

Claims

CLAIMS:

1. A connector for mounting onto an electrical apparatus and for conveying electrical signals to the apparatus, the connector comprising: an insulated connector housing; a plurality of signal temiinals disposed in the connector for connecting to corresponding signal terminals of a mating connector; a ground terminal disposed in said connector housing for connecting to a corresponding ground terminal of the mating connector; and, the ground terminal including a conductive pedestal portion that is fastened to said connector housing by a conductive fastener at a mounting part of said comiector housing, to define a conductive grounding path between said ground terminal and said pedestal portion.

2. A connector according to claim 1, wherein said ground terminal is locked in place on the mounting part of said connector housing by the pedestal portion, a portion of said pedestal portion being sandwiched between said fastener and said housing mounting part.

3. A connector according to claim 1, wherein said ground terminal and said pedestal portion are integrally formed together as a single piece.

4. A connector according to claim 1, wherein said ground terminal and said pedestal portion are bent at an angle to each other.

5. A connector according to claim 1, wherein said pedestal portion includes a semi-circular flange member that is sandwiched between a head of a mounting screw and said connector mounting part.