1. Field of the Invention
The invention relates to a connector for an electric or electronic device such as a circuit board, and to a terminal fitting therefor.
2. Description of the Related Art
Japanese Unexamined Patent Publication No. H06-203928 discloses a connector mountable on a printed circuit board. This connector has small and large terminal fittings bent in L-shape. The connector also has a housing with press-in holes arranged side by side at even intervals along a width direction at upper and lower stages. The upper press-in holes are aligned vertically with the lower press-in holes. One end of each small terminal fitting is inserted into the press-in hole at the lower stage to project forward. The other end of each small terminal fitting projects back from the housing and then is bent down. One end of each large terminal fitting is pressed into the press-in hole at the upper stage to project forward by the same distance as the corresponding side of the small terminal fitting. The other end of the large terminal fitting projects back from the housing by a longer distance than the corresponding end of the small terminal fitting and is then bent down. The rear ends of the large and small terminal fittings are fixed to conductor regions on the circuit board. This circuit board connector has an advantage of mounting the terminal fittings at a high density along the width direction of the housing, and thus achieves miniaturization of the housing along the width direction.
The rear ends of the terminal fittings at the upper and lower stages of the above-described connector are arrayed one after another along the depth direction at the rear end of the housing. Thus, a dimension of the entire connector along the depth direction tends to be large.
Another known a connector has press-in holes at an upper stage offset from the press-in holes at the lower stages by half the interval between the press-in holes. In this example, rear ends of terminal fittings at the upper and lower stages can be arrayed side by side at the same distance rearward of the housing. Thus, the connector can be made smaller along depth direction. However, this known connector is enlarged along width direction. Thus, there has been an earnest demand for improvements.
The present invention was developed in view of the above problems and an object thereof is to miniaturize a connector.
The invention relates to a connector for an electric or electronic device, such as a circuit board. The connector has a housing to be mounted on an electric or electronic device. Terminal fittings are mounted substantially side by side along width direction at each of a plurality of stages in the housing. Each terminal fitting has opposite front and rear ends. A terminal connecting portion is formed at the front end of each terminal fitting and projects forward of the housing for connection with a mating terminal. A device connecting portion is formed at the rear end of each terminal fitting and projects back from the housing. The device connecting portion is bent toward the electric or electronic device for connection with the electric or electronic device. The device connecting portions are narrower than the terminal connecting portions.
The terminal connecting portions of at least certain of the terminal fittings are aligned along the height direction through the respective stages. However, the device connecting portions of these terminal fittings are arranged in different areas defined by dividing the terminal fittings along width direction by the same number as the number of the stages. Thus, the device connecting portions are arrayed transversely in one row at positions spaced back by the same distance from the housing. Accordingly, the width of the housing can be shortened and, simultaneously, the backward projecting distance of the terminal fittings from the housing can be shortened. Therefore, a mounting space is smaller and the material cost and the production cost of the housing are reduced.
Two terminal fittings have their terminal connecting portions substantially vertically aligned, but have their board connecting portions offset to substantially opposite widthwise sides with respect to longitudinal axes of the terminal connecting portions. However, these laterally offset device connecting portions of the two stages are arrayed transversely in one row at positions distanced back by substantially the same distance from the housing.
The terminal fittings are mounted by pressing the terminal connecting portions into press-in holes in the housing. Steps preferably are defined between the terminal connecting portions and the device connecting portions for pressing the terminal connecting portions into the press-in holes. The steps preferably are substantially normal to the longitudinal axes of the terminal connecting portions.
The device connecting portion preferably is fixable to the electric or electronic device by the reflow soldering. Reflow soldering means that solder is applied to the circuit board beforehand and the mounting portions of the terminal fittings are placed on the solder. The solder then is melted in a high-temperature environment to connect the mounting portions with the circuit board. In other words, reflow soldering is a process that enables the soldering of components through a gradual and controlled heating of the components in a heated environment (such as in a furnace, typically a belt furnace). In particular, a paste formed of solder powder and flux suspended in an organic vehicle is melted by the application of heat so that the components are joined through the mass heating of the preplaced solder paste to solder fillets in the metallized surfaces thereof.
Bent portions at the rear ends of the terminal fittings preferably are wider and/or thicker than the device connecting portions to increase bending rigidity. The board connecting portions can be bent with high precision by increasing the bending rigidity of the bent portions of the terminal fittings, and the mounting portions at the ends thereof can be arranged in proper postures to face the circuit board. Thus, the lower surfaces of the mounting portions can be pressed against the solder applied to the circuit board in wide areas, and the mounting portions can be fixed securely and strongly. Precise reflow soldering can be expected due to the precise bending of the terminal fittings.
As noted above, the width of the housing can be shortened and, simultaneously, the backward projecting distance of the terminal fittings from the housing can be shortened. These desirable results are achieved partly because the board connecting portions are narrower than the terminal connecting portions. Additionally, the bent portions are widened to increase bending rigidity so that the narrower board connecting portions can be bent with high precision and the mounting portions at the leading ends of the board connecting portions can be arranged in proper postures to face the circuit board. As a result, precise reflow soldering can be achieved.
The housing preferably is mounted while being slightly lifted from the electric or electronic device and/or a recessed surface is formed in at least part of a surface of the housing substantially facing an arranging surface of the device to provide a flux escaping space between the recessed surface and the arranging surface of the device.
The invention also relates to the above-described bent terminal fitting.
FIGS. 7(A) and 7(B) are perspective views of first and second terminal fittings.
FIGS. 8(A) and 8(B) are plan views of the first and second terminal fittings.
A first embodiment of the invention is described with reference to FIGS. 1 to 10. As shown in
As shown in FIGS. 2 to 6, the housing 20 is a wide block-shaped structure made e.g. of a synthetic resin and having opposite front and rear ends. A fitting recess 21 is formed in the front end of the housing 20 and is configured for receiving a mating female housing (not shown). The housing 20 has a base wall 22 at the rear end of the fitting recess 21 and press-in holes 24 extend through the base wall 22. The press-in holes are formed substantially side by side substantially along a width direction WD at upper and lower stages in the base wall 22. As shown in
As shown in
Each terminal fitting 11 is formed by bending a narrow and long busbar into a substantially in L-shape. A terminal connecting portion 12 is formed at one end of the terminal fitting 11 and is configured for connection with a female terminal fitting (not shown) mounted in the mating housing. A board connecting portion 13 is formed at the end of the terminal fitting 11 opposite the terminal connecting portion 12 for connection with a conductor on the PCB 40 by soldering, press-fitting, clamping or the like. The first and second terminal fittings 11A, 11B are classified depending on the extension of the board connecting portions 13.
The terminal connecting portion 12 is a wide tab and is pressed into a press-in hole 24 of the housing 20 from behind. As shown in
As shown in
The board connecting portion 13 is narrow and is smaller than about half the width of the terminal connecting portion 12.
As shown in
The board connecting portion 13 of the second terminal fitting 11B is formed at the rear end of the terminal connecting portion 12, and is offset in a second direction along the widthwise direction WD opposite to the first direction from the longitudinal axis X of the terminal connecting portion 12, e.g. to left when viewed from behind. Furthermore, the board connecting portion 13 is bent down after projecting back from the rear of the terminal connecting portion 12.
The first and second terminal fittings 11A, 11B are arranged to substantially vertically align the terminal connecting portions 12, as shown in
An interval between the mounting portions 16 of the two terminal fittings 11 is set to be exactly half the interval between the mounting portions 16 of the adjacent second terminal fittings 11B.
A bent reinforcement 17 is defined on part of the board connecting portion 13 of each terminal fitting 11A, 11B adjacent the rear end of the terminal connecting portion 12. The reinforcement 17 is slightly wider than the lower part of the terminal connecting portion 12 to increase bending rigidity. An outer surface of the reinforcement 17 is substantially flush with the bulging surfaces of the stoppers 15 and an inner surface is slightly offset towards the outer side from the longitudinal axis X of the terminal connecting portion 12. A tapered step is defined at the bottom end of the reinforcement 17 to alleviate stress.
Each terminal fitting 11A, 11B has a rearwardly facing pressing surface 18 at the rear end of the terminal connecting portion 12 and the stoppers 15. The pressing surface 18 is substantially normal to the longitudinal axis X of the terminal connecting portion 12 in an area larger than about half the width of the stoppers 15. The pressing surface 18 can be engaged a jig for pressing the terminal connecting portion 12 into the press-in hole 24.
Fixing members 30 are mountable at the opposite left and right surfaces of the housing 20 for fixing the housing 20 on the PCB 40 by soldering. Each fixing member 30 is formed unitarily by press-working a metal plate and includes a main plate 31 and a mounting plate 32 to one another. Solder entering holes 33 are formed at specified intervals substantially along longitudinal direction LD in the mounting plate 32 in the shown example.
A mounting groove 27 for the fixing member 30 is formed in each of the left and right side walls 26 of the housing 20. Rear parts of the side walls 26 project from the rear surface of the housing 20 to protect soldered portions of the terminal fittings 11. The fixing member 30 is mounted preferably so as not to come out by pressing the main plate 31 down into the mounting groove 27 from a side opposite the PCB 40 and positioning the mounting plate 32 slightly below the bottom surface of the housing 20, as shown in
The bottom surface of the housing 20, excluding the side walls 26, has a recessed surface 28 to provide a flux escaping space 29 as shown in
A jig is urged against the pressing surface 18 at the right side area of the rear end of the terminal connecting portion 12 to insert the terminal connecting portion 12 of the second terminal fitting 11B into the press-in hole 24 at the lower stage. Thus, the press-in portions 14 are pressed into the press-in hole 24 and bite into the lateral walls of the press-in hole 24. The pushing operation is stopped when the stoppers 15 contact the back edges of the entrance 24A (see
Similarly, a jig is used to urge the first terminal fittings 11A into the press-in hole 24 at the upper stage after all of the second terminal fittings 11B have been inserted.
In this way, the terminal fittings 11A, 11B at the upper and lower stages project by substantially the same distance in the fitting recess 21 of the housing 20 as shown in
The fixing members 30 are positioned and mounted into the mounting grooves 27 of the opposite side walls 26 of the housing 20.
Solder preferably is applied beforehand at parts of the outer surface of the PCB 40 where soldering is planned. Thereafter, the connector 10 is placed on the surface of the PCB 40 so that the mounting portions 16 of the board connecting portions 13 of the terminal fittings 11A, 11B and the mounting plates 32 of the fixing members 30 are at the solder applied positions.
The PCB 40 having the connector 10 placed thereon is conveyed to a high-temperature environment, such as in a high-temperature oven (not shown), in this state. Thus, the solder applied to the PCB beforehand becomes molten to attach to the mounting portions 16 of the terminal fittings 11A, 11B. The molten solder also attaches to the peripheral edges of the mounting plates 32 of the fixing members 30 and enters the solder entering holes 33 to attach to the inner surfaces of the holes 33.
The solder cools and solidifies so that the board connecting portions 13 of the terminal fittings 11A, 11B are secured and electrically connected to the corresponding conductor paths, and the mounting plates 32 are secured to the PCB 40. Accordingly, the housing 20 is mounted while being slightly lifted from the PCB 40.
The bent reinforcing portion 17 of the board connecting portion 13 of each terminal fitting 11 is formed wider to increase the bending rigidity. Thus, the board connecting portion 13 can be bent with high precision and the mounting portion 16 at the leading end is arranged in a proper posture to face the PCB 40. Thus, a wide area of the lower surface of the mounting portion 16 can be pressed against the solder applied to the PCB 40 beforehand, and the mounting portion 16 can be secured securely and strongly.
Flux preferably is applied over the solder to improve the wettability of the solder and/or to prevent oxidation in the reflow soldering. This flux similarly becomes molten when the solder is melted. The melted flux can flow down under the bottom surface of the housing 20, and could lift the housing 20 when being solidified. Thus, the flux may peel off the soldered portions of the terminal fittings 11 and may enter the fitting recess 21 between the male and female terminal fittings at the time of connection with the mating housing to cause an erroneous connection. Particularly, in the applied reflow soldering solder is applied to the electric/electronic device such as the circuit board 40 beforehand, the mounting portions 16 of the terminal fittings 11 are placed on the solder, and the solder is melted in a high-temperature environment to connect the mounting portions 16 with the circuit board 40. In other words, reflow soldering is a process that enables the soldering of components through a gradual and controlled heating of the components in a heated environment (such as in a furnace, typically a belt furnace or infrared, convection and/or vapor phase heating systems). A pasted form of solder powder and flux suspended in an organic vehicle preferably is arranged on at least part of the components to be connected and melted by the application of heat so that the components are joined through the mass heating of the preplaced solder paste in order to solder fillets in the metallized surfaces thereof. The flux facilitates the production of the solder joint, and may be used to remove oxides from the respective conductive surfaces to be joined and to enable better wetting or wettability or reduce the surface-tension of the portions to be soldered. Flux is usually a liquid or solid material frequently based on natural/synthetic rosin as a main component.
However, in this embodiment, the housing 20 is mounted while being slightly lifted from the PCB 40 and the recessed surface 28 preferably is formed in at least part of the bottom surface of the housing 20 to provide a wide flux escaping space 29 between the recessed surface 28 and the outer surface of the PCB 40. Therefore, even if the flux should flow down, it is accommodated in the escaping space 29 and does not cause the aforementioned problems.
As described above, the board connecting portions 13 of the respective terminal fittings 11A, 11B are offset towards the opposite widthwise sides with respect to the longitudinal axes X of their terminal connecting portions 12. Thus, the board connecting portions 13 of the terminal fittings 11A, 11B at the upper and lower stages can be arrayed transversely in one row at positions spaced back from the housing 20 by substantially the same distance. Additionally, the mounted board connecting portions 13 are offset along the width direction WD of the terminal fittings 11 while the terminal connecting portions 12 of the fitting terminals 11A, 11B are aligned vertically.
As a result, the width of the housing 20 can be shortened and, simultaneously, the backward projecting distance of the terminal fittings 11 from the housing 20 can be shortened. Therefore, a mounting space can be made smaller and the material cost and the production cost of the housing 20 can be reduced.
Further, the pressing surface 18 is substantially normal to the pressing direction and takes advantage of the area of the rear end surface of each terminal connecting portion 12 not coupled to the board connecting portion 13. Thus, the operation of mounting the terminal fitting 11 by pressing it can be smoothly and efficiently performed.
The board connecting portions 13 are narrower than the terminal connecting portions 12. Thus, the bending precision of the board connecting portions 13 could be reduced. However, the board connecting portions 13 have wider and/or thicker reinforcements 17 to increase the bending rigidity and to achieve highly precise bends. Thus, the mounting portions 16 can be arranged in proper postures to face the PCB 40, and reflow soldering can be performed precisely to achieve strong attachments to the PCB 40.
The terminal fittings 51 may have a poor bending rigidity due to the narrow material. However, bent portions thereof are widened and/or thickened to form reinforcements 57. As a result, the board connecting portions 53 can be bent precisely and the mounting portions 54 can be arranged in proper postures to face the PCB 40. Thus, precise reflow soldering can be expected, and the board connecting portions 53 can be fixed securely and strongly.
The invention is not limited to the above described and illustrated embodiments. For example, the following embodiments are also embraced by the technical scope of the present invention as defined by the claims. Beside the following embodiments, various changes can be made without departing from the scope and spirit of the present invention as defined by the claims.
The board connecting portions of the terminal fittings at the upper and lower stages can be offset in opposite widthwise directions WD.
The invention is also applicable to connectors in which terminal fittings are mounted at one, three or more stages. In the case of connectors in which terminal fittings are mounted at three or more stages, board connecting portions of the terminal fittings at the respective terminal fittings are arranged in different areas defined by dividing the terminal fittings along width direction WD preferably by the same number as the number of the stages.
The terminal fittings are not limited to those mounted later by being pressed into the press-in holes as illustrated in the above embodiments, and may be integrally mounted by insert molding.
As a means for connecting the terminal fittings with the PCB, flow soldering may be employed according to which the leading ends of the board connecting portions are inserted into through holes formed in the PCB and let to float in a molten solder bath to be solder-connected.
Number | Date | Country | Kind |
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2004-313084 | Sep 2004 | JP | national |
2004-313085 | Sep 2004 | JP | national |