JP3286208B2 - Design method of insulation displacement terminal - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for designing a press contact terminal designed to obtain predetermined characteristics.

[0002]

2. Description of the Related Art Generally, a press contact terminal 1 has a press contact blade 3 having a slot 2 formed between a pair of beams as shown in FIG. 1, and an electric wire 5 having a core wire 6 and an insulating coating 7 is connected to the slot 2 as shown in FIG. Is inserted from the tip side (top in the figure)
The core wire 6 is pressed against the press-contact blade 3 while the insulating coating 7 is pierced, so that the connection between the electric wire 5 and the terminal 1 is achieved. It is required to set the pressure contact characteristics of the pressure contact blade 3 according to the electric wire 5 to be pressed. Conventionally, a simple method as shown in FIG. 5 has been known as a method of designing the press contact terminal 1 to satisfy such a demand.

[0003] In describing this technique, when designing the insulation displacement terminal 1, first, the insulating coating 7 of the electric wire 5 is removed by a predetermined range to expose the core wire 6. And the insulating coating 7
The core wire 6 from which the wire is removed is sandwiched between the probes 11 and 12, and a load (arrow) is applied to the wire 5 by the probe 12 to compress the wire 5 and measure the compression load and the height of the core wire. In this case, when the core wire 6 is a stranded wire composed of a plurality of element wires, for example, a seven-stranded wire, the relationship between the compression load and the core wire height is as shown by the lines 21a and 21b in FIG. That is, when the core wire 6 made of the stranded wire receives a compressive load, the arrangement of the strands changes as shown in FIG. 7, and during the compression of the core wire 6 (reduction of the core wire height), up to the point P in FIG. The compression load changes irregularly due to such a change in the arrangement of the wires (line 21a). However, when the compression load is further compressed, the stranded wires are integrated and start to behave like a single wire.
The load rises sharply (line 21b).

[0004] Therefore, the slot width A1 of the press-connecting terminal and the terminal in the press-contact state at the predetermined press-contact position are set so that the press-contact is performed in the region where the load rises rapidly (for example, point Q in the figure). A reaction force corresponding to the displacement amount B1, the press-contact state slot width C1, and the terminal displacement amount B1 is obtained. In other words, the curve 22 indicating the relationship between the displacement due to the elastic deformation of the terminal from the slot width A1 before the pressure contact and the reaction force is the point Q.
The beam width, plate thickness, slot length, and the like of the press contact terminal 1 are designed to pass through.

[0005]

However, according to the above-mentioned design method, even if the characteristics are satisfied at the initial stage in the actual press-connecting, the stress of the press-connecting blade is relaxed after a long time in the press-connecting state. The present inventors have investigated and found that due to thermal gradients due to changes in ambient temperature, etc., minute mutual movement between the wire strands or between the wire strands and the terminals occurs, which is the Deterioration occurs in conjunction with oxidation. For this reason, it is difficult to sufficiently predict the connection characteristics that satisfy the requirements even after the durability from the design stage.

[0006] Therefore, in the case of the conventional method as described above, after the pressure contact terminal is actually produced, the electric wire is pressure-contacted, and the quality is determined by durability evaluation to produce a product.

Further, in the above-mentioned design method, as shown in FIG. 5, the characteristics are measured by simply compressing the electric wire from which the insulating coating 7 has been partially removed from above and below. Since the electric wire 5 is inserted from the upper part of the slot 2 of the U-shaped press contact terminal 1 as shown in the drawing, the electric wire 5 is also subjected to a force from the insertion direction, and the behavior different from the case of the above-described design method with respect to the change in the wire arrangement and the like. Is shown. Further, in the actual pressure welding, the insulating coating 7 of the electric wire 5 is broken by the operation of inserting the electric wire into the slot 2 at the initial stage of the pressure welding, and the insulating coating 7 is previously removed only in a predetermined range as shown in FIG. The conditions are very different from the ones.

[0008] In particular, as the diameter of the electric wire and the size of the press-contact portion have been reduced in response to the recent miniaturization of equipment, the results obtained by the above-described simple design method and the actual press-contact characteristics And the difference tends to be noticeable, and since such a difference from the actual one leads to an increase in the number of trial productions, etc.,
Improvement is desired.

The present invention has been made in view of the above circumstances, and allows a design to be made based on data obtained by measurement under conditions approximate to actual pressure connection, and predicts connection characteristics after endurance at the design stage. Based on the prediction, the design method of insulation displacement terminal that can satisfy the required connection characteristics even after durability
The purpose is to provide the law .

[0010]

The invention according to claim 1 is
A method for designing a pressure contact terminal having a pressure contact blade having a slot in accordance with an object wire, by pressing the object wire against a sample having a pressure contact blade having a slot, and a predetermined endurance time under a predetermined atmosphere condition. A contact pressure evaluation test for measuring the contact resistance and contact load between the wire after the passage and the sample and determining whether the target wire is broken is repeatedly performed by changing the slot width, and based on the data, In the variation range of the slot width and the contact load, the contact resistance is stable, and the range in which the wire break does not occur is set as an allowable range, and the contact load after the lapse of the predetermined endurance time is within the allowable range. In order to generate an initial contact load, specifications relating to the slot width of the press contact blade and the displacement-reaction characteristic are set.

According to this design method and the above-mentioned press contact terminal designed by this method, the slot width and the like are set based on data from a press contact state evaluation test using a sample having a press contact blade similar to an actual press contact terminal. Therefore, there is no difference between the result and the actual pressure contact characteristics.

Furthermore, since the pressure is set based on the data obtained by the pressure contact state evaluation test after the lapse of a predetermined durability time under a predetermined atmosphere condition, when the designed pressure contact terminal is actually used, the electric wire is pressed. After a long period of time, stress relaxation of the press-contact blade occurs, or changes in the state of the electric wires (such as slight mutual movement between the electric wires or between the electric wires and the terminal) occur. In addition, a good wire pressure contact state in which the contact resistance is stable and the wire is not broken can be maintained.

In the above design method, a slot width allowable range corresponding to an allowable range of a contact load after a lapse of a predetermined durability time under a predetermined atmosphere condition is determined based on data obtained by repeatedly performing a pressure contact state evaluation test, and the slot width is designed. It is preferable that the range considering the value tolerance is set to be included in the slot width allowable range.

In this way, even if the various values at the time of manufacture deviate from the design values within the range of the tolerance, the characteristics of the press contact terminal are maintained within an appropriate range.

In the above-mentioned design method, a plurality of samples having press-contact blades having different slot widths are prepared, and the press-contact state evaluation test is performed on each of the samples. Based on the data, the plurality of samples are selected from the plurality of samples. It is preferable to select a material that satisfies the condition that the contact load after a lapse of a predetermined durability time under a predetermined atmosphere condition falls within the above-mentioned allowable range, and form a press-contact blade with the selected sample.

In this way, the sample used in the pressure-contact state evaluation test for design is effectively used, and the design and manufacture of the pressure-contact terminal are facilitated.

[0017]

Embodiments of the present invention will be described with reference to the drawings. In designing the insulation displacement terminal of the present invention,
As shown in FIG. 2, a plurality of types of press contact blades 3A, 3B... 3S... That is,
Each sample 1A, 1B... 1S has pressure contact blades 3A, 3B... 3S... Formed by a pair of beams connected at one base end, and slots 2A, 2B. Are the slot widths W1, of the pressing blades 3A, 3B... 3S.
W2 ... WS ... are different from each other, and W1> W2 >>...> WS
> ... In the following description, the term “slot width” simply refers to the slot width in a state before wire pressure welding (a state in which the wire is not pushed open). The slot width at a predetermined press-contact position in a state where the electric wire is pressed and the press-contact blade is pushed open is referred to as a press-contact state slot width.

As a press-contact state evaluation test, each of the above-mentioned samples is pressed against a specific target electric wire, a contact resistance and a contact load are obtained immediately after the press-contact, and the core state of the electric wire after the press-contact is observed. Check for cuts.

Here, the contact load is determined by a displacement-reaction characteristic and a displacement-reaction force characteristic of a sample obtained by removing an electric wire from a sample after pressure contact so as not to affect a terminal by a conventionally known method. , And the displacement amount in the wire pressure contact state. In other words, displacement-reaction characteristics can be obtained by measuring the force F and the displacement while applying the force F in the direction in which the press-contact blade 3 is pushed open as shown in FIG. For example, if the sample is provided with the press-contact blade 3A having a slot width of W1, FIG.
The characteristics are as shown by the line To1 in the middle. Then, a contact load Fo1 corresponding to the reaction force of the point Po1 is obtained by plotting the displacement measured beforehand when the electric wire is pressed against the line To1. Similarly, a sample provided with a press-contact blade 3B having a slot width of W2 or a press-contact blade 3 having a slot width of Ws
The line T representing the displacement-reaction characteristic also applies to a sample provided with S
Points Po2 and Pos on o2 and Tos according to the displacement during wire welding
Are obtained as contact loads Fo2 and Fos.

In this way, the initial contact resistance (displacement-reaction characteristic) and the contact load of each sample are determined, and the initial contact showing the relationship between the initial slot width and the contact resistance is obtained from these data. Resistance behavior (line R
o) and the initial contact load behavior (line Co) indicating the relationship between the pressed state slot width and the contact load in the initial stage. Further, based on the observation of the presence / absence of a wire break, a wire break occurrence region (a region where the slot width is equal to or less than a predetermined value) is examined.

Furthermore, the contact resistance is measured by performing the above-described pressure-contact state evaluation test even after a predetermined endurance time has elapsed under a predetermined atmosphere condition after pressing the electric wire of each sample. Displacement-reaction force characteristics after endurance (after a predetermined endurance time has elapsed) (lines Te1, Te2,
Tes) and the points Pe1,
The contact loads Fe1, Fe2, and Fe of Pe2 and Pes were examined, and the contact resistance behavior after endurance (line R
e) and the contact load behavior after endurance (line Ce) are determined, and the wire breakage occurrence region is examined. As the predetermined atmosphere condition, various test conditions conventionally used, such as high-temperature storage and cooling / heating cycle, can be used assuming actual durability.

As shown in this figure, the contact resistance increases as the slot width increases, but is kept constant in a range where the slot width is smaller than a certain value. And
In order to suppress the variation in the contact resistance due to the manufacturing error of the press contact terminal and the aging, it is required that the pressure contact terminal be in a region where the contact resistance is stable. Further, wire breakage occurs in a region where the slot width is small. When the slot width becomes larger than a certain value, the wire breakage becomes zero.

Therefore, the range in which the contact resistance is stable after the endurance and the wire break does not occur is defined as the allowable range RAe. In this case, when the post-durability contact load Fe2 at the boundary point R2 (slot width W2) is obtained, this is calculated as the required minimum contact load F2.
N. In addition, each point Po1, Po2, Po of the lines Co, Ce
s, Pe1, Pe2, and Pes are shifted sideways to obtain slot widths W1,
When plotted on W2 and Ws and connected to each other, lines Co ′ and Ce ′ indicating the relationship between the contact load and the slot width before pressure welding are obtained, and a straight line passing through the line Ce ′ and the point R2 and perpendicular to the horizontal axis is obtained. , The required minimum contact load FN can also be obtained. In addition, the slot width W2 corresponding to the required minimum contact load FN is the upper limit of the allowable range of the slot width.

Based on such data, in order to generate an initial contact load such that the contact load falls within an allowable range,
The specifications (beam width, thickness, etc.) related to the slot width and displacement-reaction characteristics of the press contact blade are set.

For example, when the specifications other than the slot width, such as the beam width and the thickness, are the same as those of the sample, the slot width is set to the allowable range RAe. It is particularly desirable that the range taking into account the tolerance α of the design value of the slot width is the above-mentioned allowable range R.
It is desirable to set it so as to be included in Ae. In this way, even if the slot width of the product varies within the design tolerance, it does not deviate from the above-mentioned allowable range.

In this case, for example, among the samples shown in FIG. 2, those having a slot width of Ws have a range (Ws ±
Since α) satisfies the condition of being included in the allowable range RAe, this sample 1S may be selected, and a press-contact blade of a press-contact terminal as a product may be formed. FIG.
In the meantime, RAo indicates a range in which the contact resistance is stable in the initial stage and the wire break does not occur. Initially, it is necessary to be within this range, and a slot width of Ws satisfies this condition.

In this design method, in the above-described example, the press-contact blade of the press-contact terminal as a product is selected from the samples used for measurement and evaluation. Even when a different press contact terminal is manufactured, it can be designed using the data of FIG. In this case, a post-durability compression load within an allowable range is determined, an initial contact load corresponding to the compression load is determined from the above data, and a slot width or the like may be set so as to obtain the initial load. More specifically, for example, in order to obtain a post-durable compressive load Fes equivalent to that of a slot having a width of Ws in the sample, an initial contact load Fos corresponding thereto is obtained, that is, an initial displacement. It is sufficient to examine the reaction force characteristic and set specifications so that the characteristic (broken line) passes through the point Pos.

According to such a design method, since the crimping state evaluation test for the design is performed using a sample having a crimping blade similar to the actual crimping terminal, the result and the actual crimping characteristics are compared. There is no difference.

The crimp terminal designed and manufactured by such a method has good characteristics even when a long time (durable time) has passed since the wire was crimped when actually used. maintain. In other words, when a long time has passed since the wire was pressed, stress relaxation of the press-contact blades occurred, or the state of the wire changed (small reciprocal movement between wires and between wires and terminals). Etc.), but the contact resistance is stable even after such durability, and a good wire pressure contact state in which the wires are not cut off is maintained.

[0030]

As described above, according to the present invention, a contact state evaluation test for measuring a contact resistance and a contact load after a predetermined endurance time has elapsed by pressing a target electric wire against a sample having a pressure contact blade and discriminating breakage of a wire. Based on the data obtained by repeatedly changing the slot width, the slot width of the pressure welding blade is set so as to satisfy the conditions that the contact resistance is stable after a predetermined endurance time has elapsed and the wires do not break. Therefore, it is possible to easily and accurately design a press contact terminal capable of satisfying required connection characteristics even after durability.

[Brief description of the drawings]

FIG. 1 is a schematic diagram illustrating an example of a press contact terminal and an electric wire pressed against the press contact terminal.

FIG. 2 is a schematic view showing a sample used in a pressure contact state evaluation test for designing a pressure contact terminal.

FIG. 3 is an explanatory view showing deformation of the press contact terminal according to a force in a direction of pushing and opening the press contact terminal.

FIG. 4 is a graph showing a relationship between a slot width of a sample, a contact load, and a contact resistance.

FIG. 5 is an explanatory view showing a conventional press contact terminal designing method.

FIG. 6 is a graph showing a relationship between a core wire height and a compressive load when designing is performed by the method shown in FIG. 5;

FIG. 7 is an explanatory diagram showing a change in strand arrangement due to compression when the core of the electric wire is a stranded wire.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Pressure contact terminal 1A, 1B, 1S Sample 2, 2A, 2B, 2S Slot 3, 3A, 3B, 3S Pressure contact blade 5 Electric wire W1, W2, Ws Slot width

Continuation of the front page (56) References JP-A-6-52961 (JP, A) JP-A-7-220771 (JP, A) JP-A-7-22467 (JP, U) (58) Fields investigated (Int) .Cl. ⁷ , DB name) H01R 4/24

Claims (3)

(57) [Claims] 1. A method of designing a press contact terminal having a press contact blade having a slot in accordance with a target electric wire, comprising pressing a target electric wire against a sample having a press contact blade having a slot, and applying a predetermined atmosphere condition. A pressure contact state evaluation test for measuring the contact resistance and the contact load between the wire and the sample after the elapse of the predetermined durability time and determining whether or not the wire of the target wire is broken is repeatedly performed by changing the slot width. Based on the data, the range in which the contact resistance is stable and the range in which the wires do not break out of the variation range of the slot width and the contact load is regarded as an allowable range, and the contact load after the lapse of the predetermined endurance time is the allowable range. A method for designing a press contact terminal, comprising setting specifications relating to a slot width of a press contact blade and displacement-reaction characteristics so as to generate an initial contact load within a range. 2. A slot width allowable range corresponding to a contact load allowable range after a lapse of a predetermined durability time under a predetermined atmosphere condition is determined based on data obtained by repeatedly performing a pressure contact state evaluation test, and a tolerance of a design value of the slot width is determined. design method of insulation displacement terminal of claim 1, wherein a range in consideration, characterized in that the set to be included within the slot width allowable range. 3. A plurality of samples having press-contact blades having different slot widths are prepared, and the press-contact state evaluation test is performed on each of the samples. Based on the data, a predetermined atmosphere condition is selected from the plurality of samples. in contact load after a predetermined endurance time elapses to select the one that satisfies the condition that falls within the allowable range, the press-connecting terminal according to claim 1, wherein forming a press-contact blade by the selected samples Design method.