Connecting method of electric wire and terminal

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a connecting method of connecting an electric wire and a terminal by applying an ultrasonic vibration.

2. Description of the Related Arts

Japanese Patent Application Laid-Open No. 7-70345 discloses a connection structure in which a covering portion of a covered electric wire is melted (molten) and removed by applying an ultrasonic vibration so as to conductively connect a core wire of the covered electric wire and a terminal.

FIG.

1

A and

FIG. 1B

each show a connector having a conventional structure in which a first member

1

and a second member

2

made of a resin face each other.

An upper surface of the first member

1

is formed with a groove portion

3

along a longitudinal direction thereof, and a small concave portion

4

is formed along a longitudinal direction of the groove portion

3

with a given interval. A terminal

5

is inserted into the groove portion

3

of the first member

1

along a longitudinal direction of the groove, and then, a covered electric wire

6

is placed on the terminal

5

. The covered electric wire

6

is placed on the terminal

5

in a state that many core wires are covered with a covering portion made of a resin.

A lower surface of the second member

2

is formed with a protrusion

7

which is fitted into the groove portion

3

of the first member

1

and a small convex portion

8

which is fitted into the concave portion

4

of the groove

3

, along the longitudinal direction thereof.

These members having the aforesaid structure are assembled in the following manner. More specifically, the terminal

5

and the covered electric wire

6

are inserted into the groove portion

3

of the first member

1

, and then, in this state, the protrusion

7

of the second member

2

is fitted into the groove portion

3

of the first member

1

so that the terminal

5

and the covered electric wire

6

are pressed down by means of the second member

2

and the first member

1

. At this time, the terminal

5

and the covered electric wire

6

are partially bent at a place where the concave portion

4

and the convex portion

8

are mutually fitted, so that these terminal and covered electric wire can be prevented from coming off.

And then, in a state that these terminal

5

and covered electric wire

6

are held between the first member

1

and the second member

2

, an ultrasonic vibration is applied to these members from an ultrasonic horn (not shown) while pressing them. A covering portion of the covered electric wire

6

is melted and removed by a heat generated by the ultrasonic vibration, and therefore, an internal core wire is exposed, and thus, the exposed core wire and the terminal

5

conductively contact with each other. With this conductive contact, the first member

1

and the second member

2

are integrally connected, so that a connector housed the terminal

5

and the electric wire can be prepared.

FIG. 2

shows an example converse to FIG.

1

A and FIG.

1

B. More specifically, a small convex portion

8

is formed in the groove portion

3

of the first member

1

, and a small concave portion

4

fitted into the convex portion

8

is formed in the second member

2

. Likewise, in this case, in the state that the terminal

5

and the covered electric wire

6

are held between the first member

1

and the second member

2

, by applying the ultrasonic vibration thereto, it is possible to conductively contact the core wire with the terminal

5

.

FIG. 3

shows a structure for preparing a multi-polar connector, and the first member

1

is formed with a plurality of groove portions

3

; on the other hand, the second member

2

is formed with a plurality of protrusions

7

which face the groove portions

3

. After the terminal is housed in the respective groove portions

3

, the covered electric wire is placed on the terminal, and thereafter, in a state that these terminal and electric wire are held between the first member

1

and the second member

2

, the ultrasonic vibration is applied to them while pressing the same, thereby a connector being made.

FIG. 4

shows a state that the terminal

5

and the covered electric wire

6

are held between the first member

1

and the second member

2

having the structure as described above. And then, these terminal

5

and the covered electric wire

6

are pressed down by the protrusion of the second member

2

so as to be overlapped each other, and thus, bent portions

5

a

and

6

a

corresponding to the convex portion

8

and the concave portion

4

are formed to prevent these terminal and covered electric wire from coming off.

However, according to the conventional structure, the core wire of the covered electric wire does not sufficiently contact with the terminal; for this reason, the conventional structure has a problem that a contact resistance becomes large.

FIG. 5

shows an ideal state that a core wire

9

of the covered electric wire and the terminal

5

contact with each other by the ultrasonic vibration. More specifically, the covering portion of the covered electric wire is melted and removed, and then, the core wires

9

are exposed and contact with the terminal

5

in a state of coming into line. Further, the exposed core wires

9

are held down by the protrusion

7

of the second member

2

so as to keep this contact state.

In actual fact, the protrusion

7

is softened by a heat generated when the covering portion of the covered electric wire is melted; as a result, as shown in

FIG. 6

, a distal end portion

7

a

of the protrusion

7

is formed. By the deformation of the protrusion

7

, it is impossible to hold down the core wires

9

, and the core wires

9

come loose in a row; for this reason, these core wires

9

can not sufficiently contact with the terminal

5

. As a result, a contact area is reduced, and a contact resistance becomes large.

In such a case, there is made a proposal of forming the second member

2

including the protrusion

7

of a resin having high heat-resistance. However, the high heat-resistant resin is expensive, and it is difficult to mold the resin; for this reason, a precision is lowered. Further, the melted covering portion of the covered electric wire and the second member

2

are not effectively joined together; for this reason, there is a problem that these members are not firmly assembled.

SUMMARY OF THE INVENTION

The present invention has been achieved with such points in mind.

It therefore is an object of the present invention to provide a connecting method of connecting an electric wire and a terminal, which can arrange a plurality of core wires of a covered electric wire on a terminal so as to come into line, and can make a preferable contact between the core wires and the terminal, thereby reducing a contact resistance.

To achieve the object, according to a first aspect of the present invention, there is provided a connecting method of an electric wire and a terminal, comprising the steps of: placing a covered electric wire having a plurality of core wires covered with a covering portion made of a resin, on a terminal; applying an ultrasonic vibration or an ultrasonic wave oscillation to the covered electric wire in a state of pressing the covered electric wire against the terminal so as to melt and remove the covering portion so that the plurality of core wires are arranged on the terminal in parallel; and pressing the parallelly arranged core wires against the terminal so that the core wires and the terminal conductively contact with each other.

According to the connecting method of an electric wire and a terminal, the covered electric wire is placed on the terminal, and thereafter, the ultrasonic vibration or the ultrasonic wave oscillation is applied in a state of pressing the covered electric wire against the terminal. In this case, the pressing means includes, for example, an ultrasonic vibration applying horn, and other pressing members. When applying the ultrasonic vibration in a state of pressing the covered electric wire against the terminal, the covering portion of the covered electric wire is melted and removed, and then, by pressing, the core wires are arranged on the terminal in parallel. In this state, the core wires are pressed against the terminal so that the core wires and the terminal conductively contact with each other.

According to the connecting method of the present invention, the core wires are arranged on the terminal in parallel by pressing when melting and removing the covering portion of the covered electric wire by the ultrasonic vibration, and the core wires thus arranged are pressed against the terminal so that the core wires and the terminal conductively contact with each other. Therefore, a preferable connection between the core wires and the terminal can be obtained, and also, a contact resistance can be reduced.

According to a second aspect of the present invention, as it depends from the first aspect, wherein the terminal and the covered electric wire are housed in the groove portion of a first resin member in a state that they overlap each other; the ultrasonic vibration is applied in a state of pressing the covered electric wire against the terminal by means of an ultrasonic vibration applying horn; and the protrusion of a second resin member is inserted into the groove portion so as to press the core wires against the terminal.

According to the connecting method of the present invention, the covered electric wire is overlapped on the terminal in the groove portion of the first resin member, and in this state, when applying an ultrasonic vibration to these covered electric wire and terminal while pressing them by means of the ultrasonic vibration applying horn, the covering portion of the covered electric wire is melted and removed, and then, the core wires are arranged on the terminal in parallel by pressing from the horn. In this state, the protrusion of the second resin member is inserted into the groove portion so as to press the core wires against the terminal.

Accordingly, in the present invention, the core wires are arranged on the terminal in parallel by pressing when melting and removing the covering portion of the covered electric wire by the ultrasonic vibration, and the core wire thus arranged are pressed against the terminal by inserting the protrusion into the groove portion, and thereby the core wires and the terminal conductively contact with each other. Therefore, a preferable connection between the core wires and the terminal can be obtained, and also, a contact resistance can be reduced.

Further, the core wire and the terminal conductively contact with each other by applying the ultrasonic vibration and pressure to them from the ultrasonic horn, and thereafter, the protrusion of the second resin member presses the core wire against the terminal, so that the core wire can be prevented from coming loose without the protrusion being softened by the ultrasonic vibration. Therefore, it is possible to improve reliability in a connection between the core wire and the terminal.

According to a third aspect of the present invention, as it depends from the second aspect, wherein the first resin member and the second resin member are welded together in a state that the protrusion of the second resin member is inserted into the groove portion of the first resin member.

According to the connecting method of an electric wire and a terminal, the terminal and the covered electric wire are overlapped in the groove portion of the first resin member, and ultrasonic vibration is applied to them while pressing the same. By doing so, the covering portion of the covered electric wire is melted and removed, and the core wires and the terminal conductively contact with each other, and further, the core wires are arranged on the terminal in a parallel. In this state, the protrusion of the second resin member is inserted into the groove portion so that the core wires are arranged in parallel on the terminal. And then, the first resin member and the second resin member are coupled with each other by ultrasonic welding, and thereby, it is possible to easily meltedly join the first resin member and the second resin member together.

According to a fourth aspect of the present invention, as it depends from the second aspect, wherein the first resin member is mechanically or geometrically engaged with the second resin member in a state that the protrusion of the second resin member is inserted into the groove portion of the first resin member while being pressed; and the ultrasonic vibration is applied in the state.

According to the connecting method of an electric wire and a terminal, the terminal and the electric wire are housed in the groove portion of one resin member in a state of being overlapped each other, and the protrusion of another resin member is inserted into the groove portion. And then, an ultrasonic vibration is applied in a state of pressing these terminal and electric wire. At this time, the ultrasonic vibration is applied in a range such that the covering portion overlapped with the terminal is melted and removed without welding the first resin member and the second resin member together. In this case, the first resin member and the second resin member are mechanically formed, and thereby, the covered electric wire is pressed against the terminal.

Accordingly, the first resin member and the second resin member are mechanically or geometrically coupled with each other; therefore, it is possible to disengage the first resin member from the second resin member without causing breakage in maintenance. As a result, the first resin member and the second resin member can be repeatedly use.

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS

The above and further objects and novel features of the present invention will more fully appear from the following detailed description when the same is read in conjunction with the accompanying drawings, in which:

FIG. 1A

is a cross-sectional view showing a conventional connection structure;

FIG. 1B

is a front view of the conventional connection structure;

FIG. 2

is a cross-sectional view showing a conventionally another connection structure;

FIG. 3

is a perspective view showing a conventional multi-polar connector;

FIG. 4

is a cross-sectional view showing a conventional connection;

FIG. 5

is a cross-sectional view showing a conventionally ideal connective state;

FIG. 6

is a cross-sectional view showing a conventionally non-preferable connective state;

FIG. 7

is a perspective view showing a connector housing in which a covered electric wire and a terminal are connected according to a connecting method of an electric wire and a terminal of one embodiment of the present invention, and showing an ultrasonic applying horn;

FIG. 8

is an exploded perspective view showing a connector housing in which the covered electric wire and the terminal are connected according to the connecting method of an electric wire and a terminal of one embodiment;

FIGS. 9A

,

9

B,

9

C and

9

D show a procedure of the connecting method of the electric wire and the terminal of one embodiment of the present invention;

FIG. 9A

is a cross-sectional view showing a manner of inserting the ultrasonic applying horn into a groove portion in a state that the terminal and the covered electric wire overlap each other in the groove portion;

FIG. 9B

is a cross-sectional view showing a state of applying an ultrasonic vibration to the terminal and the covered electric wire overlapped in the groove portion;

FIG. 9C

is a cross-sectional view showing a state that a covering portion of the covered electric wire is melted and removed by applying the ultrasonic vibration, and the core wires are arranged on the terminal so as to come into line;

FIG. 9D

is a cross-sectional view showing a state that the core wires, which are arranged on the terminal so as to come into line, is pressed by a protrusion of the cover;

FIG. 10

is an exploded perspective view showing a connector in which the covered electric wire and the terminal are connected according to the connecting method of a electric wire and a terminal of one embodiment of the present invention;

FIG. 11

is a perspective view showing a back side of the cover according to one embodiment;

FIG.

12

A and

FIG. 12B

show a connective relationship between a wire leading portion and the cover in one embodiment;

FIG. 12A

is a cross-sectional view showing a state before a stopper protrusion is inserted into a hole;

FIG. 12B

being a cross-sectional view showing a state before a stopper protrusion is inserted into a hole; and

FIG. 13

is a cross-sectional view showing a modified example of the connector housing and the cover in one embodiment.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The contents of U.S. Pat. No. 5,584,122 are incorporated herein by reference.

There will be detailed below the preferred embodiments of the present invention with reference to the accompanying drawings. Like members are designated by like reference characters.

FIG.

7

and

FIG. 8

show a connector housing (a first resin member)

11

in which a covered electric wire

18

and a terminal

17

are connected according to the connecting method of an electric wire and a terminal, and an ultrasonic vibration applying horn (electrode)

24

.

FIG. 8

show the connector housing

11

and a cover (a second resin member)

19

covering an electric-wire leading portion

13

of the connector housing

11

.

The connector housing

11

comprises a hood portion

12

which is coupled with a mating connector (not shown) by being fitted thereto, and an electric-wire leading portion

13

which is integrally formed at one side of the hood portion

12

.

The electric-wire leading portion

13

has a bottom wall

14

extending from the hood portion

12

, a plurality of partition walls

15

which are formed on the upper surface of the bottom wall

14

and are projected in parallel, and a groove portion

16

defined between the partition walls

15

. The groove portion

16

has a rectangular shape whose upper portion is opened in its cross section, and the terminal

17

is housed in each groove portion

16

so as to make a connection with the covered electric wire

18

. Further, each partition wall

15

on opposite sides are formed with two stopper protrusions

30

and

30

at the outside thereof. These stopper protrusions

30

and

30

are inserted (fitted) into stopper holes

23

of the cover

19

covering the electric-wire leading portion

13

.

As shown in FIG.

8

and

FIG. 11

, the cover

19

includes a cover plate

20

covering the electric-wire leading portion

13

, a plurality of protrusions

21

which are formed so as to correspond to the electric-wire leading portion

13

in the cover plate

20

, and side wall portions

22

and

22

provided outside the protrusions

21

. These side wall portions

22

and

22

are each formed with the aforesaid stopper holes

23

and

23

. Further, the lower end portion of these side wall portion

22

and

22

are each formed with partial tapers

27

and

27

corresponding to the stopper holes

23

and

23

. The partial taper

27

slides in a state of contacting with an inclined surface

29

of the stopper protrusion

30

so as to relatively guide the stopper protrusion

30

into the stopper hole

23

.

The protrusion

21

is formed into the same rectangular shape in its cross section as the groove portion

16

of the electric-wire leading portion

13

, and is provided so as to correspond to the groove portion

16

. Further, the protrusion

21

is formed so as to have a dimension slightly smaller than the groove portion

16

, and is inserted (fitted) into the corresponding groove portion

16

when the cover

19

is put on the electric-wire leading portion

13

. When the protrusion

21

is inserted into the groove portion

16

, the protrusion

16

contacts with the covered electric wire

18

housed in the groove portion

16

so as to press the covered electric wire

18

against the terminal

17

.

One side of the terminal

17

is a contact portion (not shown) which is projected into the hood portion

12

of the connector housing

11

so as to be connected with a mating terminal; the other side thereof is a flat electric-wire contact portion which is housed in the groove portion

16

and is conductively connected with the covered electric wire

18

.

As shown in

FIG. 9A

, the covered electric wire

18

is formed in a manner that a plurality of core wires

25

are covered with a covering portion

26

made of an insulative resin such as vinyl chloride or the like.

The following is a description on assembly in this embodiment.

As shown in

FIG. 9A

, the electric-wire contact portion of the terminal

17

is housed in the groove portion

16

of the connector housing

11

, and the contact portion of the mating terminal is projected into the hood portion

12

. And then, the covered electric wire

18

is placed on each terminal

17

. In this state, the ultrasonic horn

24

is inserted into the groove portion

16

, and an ultrasonic vibration or an ultrasonic wave oscillation is applied thereto while pressing the covered electric wire

18

against the terminal

17

.

As shown in

FIG. 9B

, the covering portion

26

of the covered electric wire

18

is exothermic by the ultrasonic vibration, and is melted and removed. And then, by applying a pressure to the core wires

25

from the ultrasonic horn

24

, the plurality of core wires

25

are arranged on the terminal in line, that is, in parallel. However, under such circumstances, the core wires

25

is pressed and crushed on the terminal

17

by the pressure from the ultrasonic horn

24

, and then, are deformed into an ellipse shape.

Next, As shown in

FIG. 9C

, the ultrasonic horn

24

is drawn out from the groove portion

16

, and then, as shown in

FIG. 9D

, the electric-wire leading portion

13

is closed by the cover

19

shown in FIG.

10

.

In order to close the electric-wire leading portion

13

by the cover

19

, as shown in

FIG. 12A

, first, the cover

19

is placed on the electric-wire leading portion

13

. In this state, the stopper protrusion

30

is not still inserted into the stopper hole

23

. Next, as shown in

FIG. 12B

, both side portions of the cover

19

are pressed down by manually. When the cover

19

is pressed, the stopper protrusion

30

is inserted into the stopper hole

23

so that the cover

19

is fixed on the electric-wire leading portion

13

. In this state, the protrusion

21

of the cover

19

is inserted into the groove portion

16

, and is abutted against the core wires

25

arranged on the terminal

17

, and thus, the core wires

25

are pressed against on the terminal

17

.

According to this embodiment, as described above, by the horn

24

for the ultrasonic vibration, the ultrasonic vibration is applied to the terminal

17

and the covered electric wire

18

housed in the groove portion

16

while pressing them. Thus, the core wires

25

of the covered electric wire

18

are arranged in parallel, and in this state, are pressed against the terminal

17

by means of the protrusion

21

of the cover

19

. Therefore, the core wires

25

do not come loose, so that a contact area can be sufficiently secured. As a result, a contact resistance can be reduced, and a preferable connection state of the electric wire and the terminal can be obtained.

Further, every core wire

25

is deformed into an elliptic shape by applying a pressure from the horn

24

, so that a contact area of the core wires

25

and the terminal

17

, and between the core wires

25

can be increased. Whereby a contact resistance can be reduced, and a preferable connection state can be obtained.

In this embodiment, moreover, the partial taper

27

slides in a state of contacting with the inclined surface

29

of the stopper protrusion

30

so as to relatively guide the stopper protrusion

30

into the stopper hole

23

.

Next, the following is a description on a modification example shown in FIG.

13

. In this modification example, a stopper protrusion

31

and

31

extends upwardly from the intermediate partition wall

15

and

15

, and is formed integrally therewith. On the other hand, the cover

19

is formed with a stopper hole

32

and

32

at an intermediate portion of the cover plate

20

. The covering portion

26

is melted and removed by means of the ultrasonic horn

24

, and the core wires

25

are arranged laterally in line in the groove portion

16

. In this state, the cover

19

is placed on the electric-wire leading portion

13

, and when pressing the vicinity of the stopper hole

32

, the stopper protrusion

31

and

31

is inserted into the stopper hole

32

and

32

. In This state, the stopper hole

21

and

21

securely press the core wires

25

against the terminal

17

side.

It is desirable that the connector housing

11

and the cover

19

are meltedly jointed together, instead of the stopper protrusions

30

and the stopper holes

23

in the following manner. First of all, the terminal

17

and the covered electric wire

18

are overlapped in the groove portion

16

of the connector housing

11

, and the ultrasonic vibration is applied to them while pressing the same. By doing so, the covering portion

26

of the covered electric wire

18

is melted and removed, and the core wires

25

and the terminal

17

conductively contact with each other, and further, the core wires

25

are arranged on the terminal

17

in a parallel. In this state, the protrusion

21

of the cover

19

is inserted into the groove portion

16

so that the core wires

25

are arranged in parallel on the terminal

17

. And then, the connector housing

11

and the cover

19

are coupled with each other by ultrasonic welding, and thereby, it is possible to easily meltedly join the connector housing

11

and the cover

19

together, instead of the stopper protrusions

30

and the stopper holes

23

.

While preferred embodiments of the present invention have been described using specific terms, such description is for illustrative purposes, and it is to be understood that changes and variations may be made without departing from the spirit or scope of the following claims.

Number	Name	Date
3440118	Obeda	Apr 1969
4730764	Hawkins et al.	Mar 1988
4922072	Topel et al.	May 1990
5057661	Banner	Oct 1991
5114362	Olsson	May 1992
5134249	Adachi	Jul 1992
5372665	Chafin et al.	Dec 1994
5584122	Kato et al.	Dec 1996
5857259	Johnston	Jan 1999

Number	Date	Country
197 57 349	Jul 1998	DE
198 26 925	Jan 1999	DE
7-70345	Jul 1995	JP
WO 9425970	Nov 1994	WO

Connecting method of electric wire and terminal

Information

Patent Number

Date Filed

Date Issued

Inventors

Original Assignees

Examiners

Agents

CPC

US Classifications

Field of Search

US

International Classifications

Abstract

Description

Claims

Priority Claims (1)

US Referenced Citations (9)

Foreign Referenced Citations (4)