JP2000208189A - Electric connector and contact used therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To effectively reduce the bending rigidity and torsional rigidity of a leg part to improve the solder crack resistance, bending workability and bending precision and reduce the side by forming the part extending from the bent part of the leg part to the tip so that the bending radius directional thickness of the bent part is smaller than the thickness of the leg part closer to a housing from the bent part. SOLUTION: Leg part 22 of a plurality of contacts 20 arranged vertically and longitudinally and drawn out from the side surface 12 of a box housing 10 with a bottom surface 11 facing a printed wiring board P for mounting are bent downward. Of the part extending from the bent part 22a of the leg part 22 to the tip, the bending radial directional thickness T1 of the bent part 22a is set smaller than the thickness (t) of the housing 10-side leg part 22. Accordingly, a stepped part 22b is formed on the housing 10 side of the bent part 22a, and the contact 20 at the tip of the leg part 22 integrated to a contact part 21 is soldered to the printed wiring board P in a portion (s). Thus, a bypass part can be eliminated to reduce the spring back quantity of the leg part 22, which allows the miniaturization.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention belongs to the technical field of an electrical connector mounted on a printed wiring board, and more particularly to a measure for improving solder crack resistance.

[0002]

2. Description of the Related Art In general, as an electrical connector, for example, as shown in FIG. 8, a housing 93 is disposed such that a bottom surface 91 faces a printed wiring board 92 to be mounted, and a contact 93 disposed inside the housing 93 is provided. A contact 96 having a portion 94 and a contact 95 having a leg 95 disposed outside, and a contact 96 pulled out from a side surface 97 of the housing 93.
Are bent toward the printed wiring board 92. This electrical connector is
5 is mounted by being inserted into a through hole 98 of the printed wiring board 92 or abutting on the printed wiring board 92 and soldering. In such an electrical connector, as shown in FIG.
Are drawn out of the housing side surface 97 side by side in the vertical direction and are bent downward toward the printed wiring board 92 while being parallel to each other, or a plurality of contact legs 95 are aligned in the front-rear direction. Housing side 9
7 are bent downward toward the printed wiring board 92, for example, due to the difference in the coefficient of thermal expansion between the housing 93 and the printed wiring board 92. When the gap on the wiring board side shifts, and this is repeated, the leg portions 95...
Cracks occur in the soldered joint 100 between the printed circuit board 92 and the printed wiring board 92, the conduction state becomes unstable, and a connection failure occurs.
Therefore, conventionally, as shown in FIG. 8, the leg portion 95 that has come out of the housing 93 is once detoured in a direction away from the printed wiring board 92, and then bent toward the printed wiring board 92. By reducing the bending rigidity by substantially extending the length of the legs 95, the amount of deflection that the legs 95 can absorb within the range of elastic deformation is increased, and the legs 95
The difference between the space on the housing side and the space on the printed wiring board side is absorbed by this increased amount of bending, and the solder joint 10
A technique has been proposed in which the stress applied to zero is reduced to prevent the occurrence of cracks (for example, JP-A-9-69).
371).

[0003]

However, in the proposed technique, a space for the detour portion 99 is required near the leg portion 95, so that the printed wiring board 92 of the electrical connector is required.
Occupied area of the printed wiring board 92 increases.
As a result, an electronic device incorporating this becomes bulky. Further, forming the bypass portion 99 complicates the processing, resulting in deterioration of workability and deterioration of processing accuracy. By the way, in recent years, electronic control systems for automobiles have improved reliability,
Some electronic control units have been moved from the room to the engine room in response to requests for reduction of harnesses, expansion of indoor space, etc., so that printed wiring boards, electrical connectors, etc. The heat load applied to the components has increased, and the solder crack resistance has become a problem. Further, due to space restrictions, it has been desired to further reduce these components.

The present invention has been made in view of such a point, and an object of the present invention is to reduce the bending portion and the torsional rigidity of the contact leg by thinning the bent portion of the contact leg. In addition to improving the solder crack resistance of the electrical connector, increasing the ratio of the width to the thickness of the bent portion to improve the bending workability and bending accuracy of the legs, eliminating the detour portion, etc., An object of the present invention is to reduce the size of an electrical connector by reducing the amount of springback of a leg.

[0005]

In order to achieve the above object, an electric connector according to claim 1 is provided with a plurality of contacts extending from a side surface of a housing arranged such that a bottom surface faces a printed wiring board on which the electric connector is mounted. In the electrical connector having legs bent downward toward the printed wiring board, at least the thickness of the bent portion in the direction of bending R from the bent portion to the tip of the leg is set to be smaller than that of the bent portion by the housing. It is characterized in that it is formed thinner than the thickness of the leg on the side.

This electrical connector is mounted by inserting the tip of a contact leg into a through hole of a printed wiring board or by abutting the printed wiring board and soldering. In this case, since the thickness of the bent portion in the bending R direction is smaller than the thickness of the leg portion on the housing side than the bent portion, the bending rigidity and torsional rigidity are effectively reduced, and the leg portion falls within the elastic deformation range. The displacement that can be absorbed is increased, and the difference between the spacing between the legs on the housing side and the spacing on the printed wiring board side is absorbed by the increased displacement, so that the stress applied to the solder joint is reduced, and the solder crack resistance is improved. . Also, since the ratio of the width to the thickness of the bent portion becomes large, if the tip end side of the leg is pressed in the thickness direction, the leg will bend at the bent portion having low bending rigidity, and the bending processability and bending of the leg will be improved. The accuracy is improved. In addition, since there are no detours or the like, the area occupied by the electrical connector on the printed wiring board is reduced, and the electrical connector is downsized. Further, by reducing the thickness of the bent portion in the bending R direction, it is possible to reduce the bending R value of the bent portion that is set so that cracks do not occur outside the bent portion. , The distance between the leg and the housing can be reduced, which also contributes to the miniaturization of the electrical connector.

According to a second aspect of the present invention, in the configuration of the first aspect, the leg portions of the plurality of contacts are pulled out from the side surface of the housing side by side in the vertical direction, and each of the leg portions is folded downward toward the printed wiring board in parallel. Bent.

In such an electrical connector, the displacement that can be absorbed by the legs within the range of elastic deformation increases due to the decrease in the bending rigidity of the bent portion, and the difference between the distance between the legs on the housing side and the distance on the printed wiring board side. Is absorbed by the increased displacement, the stress applied to the solder joint is reduced, and the solder crack resistance is improved. In addition, when the amount of springback is reduced, it is possible to reduce the distance between the adjacent legs, so that the area occupied by the electrical connector on the printed wiring board is reduced, and the electrical connector is further downsized.

According to a third aspect of the present invention, in the configuration of the first or second aspect, the leg portions of the plurality of contacts are pulled out from the side surface of the housing side by side in the front-rear direction and bent downward toward the printed wiring board. Have been.

In such an electrical connector, the housing is elongated in the front-rear direction, and the difference between the distance between the legs on the housing side and the distance on the printed wiring board side due to the difference in the coefficient of thermal expansion increases. Due to the decrease in rigidity, the displacement that the leg can absorb within the elastic deformation range increases, and the difference between the spacing between the housing and the printed wiring board side of the leg is absorbed by the increased displacement and applied to the solder joint. Stress is reduced,
The solder crack resistance is improved.

According to a fourth aspect of the present invention, there is provided a contact used in the electrical connector according to any one of the first to third aspects, wherein the contact portion is disposed inside the housing and the leg is disposed outside the housing. The thickness of at least the middle part from the middle part to the tip of the leg part is formed smaller than the thickness of the contact part side from the middle part.

If the contact is fixed to the housing by integral molding or the like and the distal end of the leg is pressed in the thickness direction, the electrical connector according to any one of claims 1 to 3 is manufactured. In this case, since the ratio of the width to the thickness of the intermediate portion becomes large, if the distal end side of the leg is pressed, the intermediate portion is bent at the intermediate portion having low bending rigidity, and the bending workability and the bending accuracy are improved. A bent part is formed by this halfway part.

[0013]

Embodiments of the present invention will be described below with reference to the drawings. 1 to 3 show an electric connector according to a first embodiment.

In these figures, reference numeral 10 denotes a box-shaped housing, which is arranged such that the bottom surface 11 faces the printed wiring board P on which the package is mounted. Reference numeral 20 denotes a substantially round bar-shaped contact, which is a contact portion 21 disposed inside the housing 10.
And a leg 22 disposed outside, and a portion between the contact portion 21 and the leg 22 is a side surface 1 of the housing 10.
2 and is fixed. And the housing 10
The legs 22 of the contacts 20 drawn out from the side surfaces 12 are bent downward toward the printed wiring board P, respectively.

As shown in FIG. 2, in this embodiment, the legs 22 of the plurality of contacts 20 (three rows in the figure) are pulled out from the housing side surface 12 along the vertical direction, that is, the height direction from the printed wiring board P. And are bent downward toward the printed wiring board P while being parallel to each other, whereby the legs 22 of the plurality of contacts 20 are
The legs are provided so as to overlap when viewed from the direction in which the distal ends of the legs are displaced during bending. As shown in FIG. 3, the legs 22 of the plurality of contacts 20 (seven steps in the figure) are pulled out from the housing side surface 12 side by side in the front-rear direction, and are bent downward toward the printed wiring board P, respectively. ing.

Then, as shown in FIGS. 2 and 4 (a), the thickness t ₁ of the bent portion 22a in the bending R direction from the bent portion 22a to the tip of the leg portion 22 is changed to the bent portion 22a. It is formed thinner than the thickness t of the leg 22 on the housing side, and a step 22b is formed on the housing side of the bent portion 22a. In this case, in order to avoid stress concentration, it is desirable to chamfer the step 22b whose thickness varies and the end of the bent portion 22a on the tip side. Also, as shown in FIG.
R processing is also desirable.

As a method of manufacturing the electrical connector of the above embodiment, for example, the contacts 20 ′ before being bent are temporarily fixed in a molding die of the housing 10, and a housing material is filled in the molding die to form the contacts 20 ′. An example is a method in which the contact 20 'is integrally molded with the housing 10, and then the tip end side of the contact 20' is pressed in the thickness direction. In that case, the contact 20 ′ before being bent is, as shown in FIG. 5, a contact portion 21 ′ arranged inside the housing 10.
And a leg 22 ′ disposed outside the housing 10, and the thickness t ₁ of at least the middle portion 22 ′ a from the middle portion 22 ′ a to the tip of the leg 22 ′ is set to the middle portion 22 ′.
a and the intermediate portion 2
A step 22'b is formed on the contact portion side of 2'a. The intermediate portion 22′a is formed by, for example, a so-called step crushing stamping process, that is, a process of flattening the contact 20 ′ by applying a force so as to sandwich the middle portion in the longitudinal direction of the contact 20 ′.

Therefore, the electrical connector of the first embodiment is mounted by inserting the tip of the contact leg 22 into the through hole h of the printed wiring board P or by abutting the printed wiring board P and soldering. , Housing 10
When a mating connector (not shown) is connected to the opening of
The contact portion 21 of the contact 20 comes into contact with the contact of the mating connector. In this case, since the thickness t _{1 of} the bent portion 22a in the bending R direction is smaller than the thickness t of the leg portion 22 on the housing side from the bent portion 22a, the bending rigidity inversely proportional to the cube of the thickness is effective. And the torsional rigidity drops effectively, the displacement that the leg can absorb within the elastic deformation range increases, and the difference between the spacing of the leg on the housing side and the spacing on the printed wiring board side increases the displacement. This reduces the stress applied to the solder joints and improves the solder crack resistance.

The width-to-thickness ratio of the bent portion 22a is large.
If you press the tip of the leg in the thickness direction,
The bent portion 22a is bent at the lower bending portion 22a, and the leg portion 2 is bent.
2 and the bending accuracy of the leg 22 is improved.
The degree of coplanarity (leg tip
Are aligned on one plane). Moreover, the detour part etc.
So that the electrical connector
Occupied area becomes smaller, and electrical connectors become smaller.
You. Further, the present invention makes the bending R value of the bent portion 22a different from that of the conventional product.
Including the embodiment set to be equal, but bending the bent portion 22a
R direction thickness t ₁The outside of the bent part is made thinner
Bending set so that cracks do not occur on the outer circumference
The bending R value of the portion 22a can be reduced. This
When the bending R value is set small as in
Elastic deformation region sometimes distributed near the neutral axis of bent portion 22a
And the amount of springback of the leg 22 decreases.
From this, it is possible to reduce the distance between the leg 22 and the housing 10.
This also contributes to miniaturization of electrical connectors.
You. Therefore, for example, electronic systems installed in the engine room
Electrical connector mounted on the printed wiring board of the control unit
It is suitable as.

In the above embodiment, the legs 22 of the plurality of contacts 20 are arranged in the vertical direction and the front-back direction of the housing side surface 12. However, the present invention is not limited to this embodiment, and the present invention is not limited thereto. This includes all embodiments in which at least two or more contacts are pulled out from the position and bent downward toward the printed wiring board. However, as in the above embodiment, when the leg portions 22 of the plurality of contacts 20 are pulled out from the housing side surface 12 side by side in the up and down direction and are bent toward the printed wiring board P while being parallel to each other, the bending is performed. Due to the lowering of the bending rigidity of the portion 22a, the amount of deflection, which is a displacement that the leg 22 can absorb within the elastic deformation range, increases, and the leg 22
The difference between the distance between the housing side and the distance between the printed wiring board side is absorbed by the increased amount of bending, the stress applied to the solder joint s is reduced, and the solder crack resistance is improved. Further, when the amount of springback is reduced, the space between the adjacent leg portions 22 can be reduced, the area occupied by the electric connector on the printed wiring board P and the like are reduced, and the electric connector is further downsized. Furthermore, when the leg portions 22 of the plurality of contacts 20 are pulled out from the housing side surface 12 side by side in the front-rear direction as in the above embodiment, the housing 10 becomes longer in the front-rear direction, and the leg portions due to the difference in the coefficient of thermal expansion. Although the difference between the spacing on the housing side and the spacing on the printed wiring board side of 22 increases, the amount of torsion, which is the displacement that can be absorbed by the leg portion 22 within the elastic deformation range, increases due to the decrease in the torsional rigidity of the bent portion 22a, The difference between the spacing between the legs 22 on the housing side and the spacing on the printed wiring board side is absorbed by the increased amount of torsion, so that the stress applied to the solder joint s is reduced.
The solder crack resistance is improved.

Further, if an electrical connector is manufactured using the contact 20 ', the width-to-thickness ratio of the intermediate portion 22'a is increased. It is bent at 22'a, and the bending workability and bending accuracy are improved. The bent part 22a is formed by the halfway part 22'a.

FIGS. 6 and 7 show a second embodiment of the present invention. The difference between the first embodiment and the first embodiment is the shape of the contact leg 22 on the tip side from the bent portion 22a. The other configurations are exactly the same as the first embodiment. Therefore, the same members and the same portions are denoted by the same reference numerals, and the description is referred to as they are.

In the second embodiment, the thickness t ₁ in the bending R direction over the entire length from the bent portion 22a to the tip of the leg portion 22 is set to be greater than the thickness t of the leg portion 22 on the housing side of the bent portion 22a. Is formed thin, and a step 22b is formed on the housing side of the bent portion 22a. Then, the contact 20 before bending 'In, as shown in FIG. 7, the legs 22' thickness over the entire length from the middle portion 22'a to the tip of t ₁
Is formed to be thinner than the thickness t on the contact portion side with respect to the halfway portion 22′a, and a step 22′b is formed on the contact portion side of the halfway portion 22′a. The intermediate portion 22'a can be formed by the step crushing stamping process described in the first embodiment. However, if a stepped kashiwa material is used, such additional processing is not required, so that it is simple. It is.

According to the electrical connector of the second embodiment, the same operation and effect as those of the first embodiment can be obtained.

The above embodiment is merely an example. For example, in the present invention, at least the thickness of the bent portion in the direction of bending R from the bent portion to the tip of the leg portion is determined by adjusting the thickness of the leg portion closer to the housing than the bent portion. The embodiment includes all the embodiments of the electrical connector formed thinner than the thickness of the contact, the implementation of the contact formed at least the thickness of the middle part from the middle part to the tip of the leg part, is smaller than the thickness of the contact part side than the middle part Including all forms. Further, the present invention includes all embodiments in which the features of these embodiments are appropriately combined.

[0026]

As described above, according to the electrical connector of the first aspect, the bending stiffness and the torsional stiffness of the contact leg can be effectively reduced to greatly improve the solder crack resistance of the electrical connector. By increasing the width-to-thickness ratio of the bent part, it is possible to improve bending workability and bending accuracy, and it is also possible to eliminate detours and reduce the amount of leg springback. The electric connector can be downsized. Therefore, it is suitable as an electrical connector mounted on a printed wiring board of an electronic control unit disposed in, for example, an engine room.

According to the electric connector of the present invention, the displacement which can be absorbed by the leg within the elastic deformation range is increased due to the decrease in the bending rigidity of the bent portion, and the distance between the leg on the housing side and the distance on the printed wiring board side is increased. The difference is absorbed by the increased displacement, the stress applied to the solder joint is reduced, and the solder crack resistance is improved. In addition, when the springback amount of the leg is reduced, it is possible to reduce the interval between the adjacent legs, and the occupied area of the electrical connector on the printed wiring board is reduced,
The electrical connector is further downsized.

In the electrical connector according to the third aspect, the displacement that the legs can absorb within the elastic deformation range increases due to the decrease in the torsional rigidity of the bent portion, and the distance between the legs on the housing side and the distance on the printed wiring board side increases. The difference is absorbed by the increased displacement, the stress applied to the solder joint is reduced, and the solder crack resistance is improved.

If the contact according to the fourth aspect is fixed to the housing by integral molding or the like and the tip end of the leg is pressed in the thickness direction, good bending workability and high bending accuracy are realized while maintaining the good bending workability. Can be manufactured.

[Brief description of the drawings]

FIG. 1 is a perspective view of an electric connector according to a first embodiment of the present invention.

FIG. 2 is a cross-sectional view of the electrical connector according to the first embodiment.

FIG. 3 is a longitudinal sectional view of the electrical connector according to the first embodiment.

FIG. 4A is an enlarged view of a bent portion of the electrical connector according to the first embodiment, and FIG. 4B is an enlarged view of a bent portion of the electrical connector in a modified example.

FIG. 5 shows contacts used in the electrical connector according to the first embodiment.

FIG. 6 is a longitudinal sectional view of an electrical connector according to a second embodiment of the present invention.

FIG. 7 shows contacts used in the electrical connector according to the second embodiment.

FIG. 8 is a longitudinal sectional view of a conventional electrical connector.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Housing 11 Bottom surface 12 Side surface 20 Contact 21 Contact part 22 Leg 22a Bent part 22b Step 20 'Contact 21' Contact part 22 'Leg 22'a Midway 22'b Step P Printed wiring board s Solder joint

Claims (4)

[Claims] An electrical connector wherein a plurality of contact legs drawn out from a side surface of a housing arranged such that a bottom surface faces a printed wiring board to be mounted is bent downward toward the printed wiring board. In the above, at least the bending R of the bent portion from the bent portion to the tip of the leg portion
An electrical connector characterized in that the thickness in the direction is formed to be smaller than the thickness of the leg on the housing side from the bent portion. 2. The electrical connector according to claim 1, wherein the leg portions of the plurality of contacts are pulled out from the side surface of the housing side by side in the vertical direction, and each of the leg portions is bent downward toward the printed wiring board in parallel. 3. The electrical connector according to claim 1, wherein the leg portions of the plurality of contacts are pulled out from the side surface of the housing side by side in the front-rear direction and bent downward toward the printed wiring board. 4. A contact used in the electrical connector according to claim 1, wherein the contact portion is disposed inside the housing and the leg portion is disposed outside the housing. A contact, characterized in that the thickness of at least the middle part from the middle part to the tip of the leg part is formed smaller than the thickness on the contact part side from the middle part.