JP2018155624A - Estimation method of pressure contact part resistance value of electric wire with terminal and estimation device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To estimate an electric resistance value (compressed part resistance value)in a compressed part of an electric wire with a terminal by reducing a cost as much as possible.SOLUTION: This estimation method includes: a step S3 of performing a simulation of a compressing process for compressing a terminal 30 to a conductive core wire 21; steps S4, S5 of specifying an adhesive point B at which a base material of the conductive core wire 21 and the terminal 30 are adhered by breakage of an oxide film formed on a surface of the conductive core wire 21 within a contact point A at which the conductive core 21 is brought into contact with the terminal 30 after passing through the compressing process; and steps S6, S7 of estimating an electric resistance value as a compression part resistance value R when conduction is generated between the conductive core wire 21 and the terminal 30 via the adhesive point B.SELECTED DRAWING: Figure 4

Description

  The present invention relates to an estimation method for estimating a crimping portion resistance value, which is an electrical resistance value in a crimping portion of a terminal-attached electric wire with a terminal crimped to a conductor core wire of the electric wire, and an estimation device that performs such estimation.

  Conventionally, from the viewpoint of improving the electrical characteristics of electric wires with terminals, the magnitude of the voltage drop that occurs at the crimped part where the terminal is crimped to the conductor core wire of the electric wire (in other words, the electrical resistance value at the crimped part) has been evaluated. Various proposals have been made for techniques to do this. In addition, it is thought that the voltage drop in a crimping part arises mainly due to the contact resistance (electrical resistance which exists in the interface vicinity of two conductors) in the location where the conductor core wire and the terminal are contacting.

  For example, in one of the conventional evaluation methods (hereinafter referred to as “conventional method”), a sample of the electric wire with terminal (actual) is actually manufactured, and a four-terminal measurement method (for current measurement and current measurement) And a circuit for measuring the voltage drop in the measurement target are separated from each other, thereby measuring the electrical resistance value of the measurement target while eliminating the electrical resistance of the circuit itself). The electrical resistance value at the crimping portion between the conductor core wire and the terminal is measured (actually measured) (see, for example, Patent Document 1).

JP 2009-175062 A

  In the conventional method described above, the electrical resistance value of the crimped portion of the terminal-attached electric wire (actual) is actually measured. For this reason, for example, when evaluating a wide variety of samples at the development stage of a wire with terminal, using the conventional method, after actually producing a large number of prototypes, measuring the electrical resistance of the crimped part (actual measurement) ) Will be repeated. As a result, in the conventional method, the manufacturing cost of the mold for manufacturing the prototype and the evaluation man-hour for actual measurement become large, and the evaluation cost of the electric wire with terminal can be increased. Therefore, there is a demand for a method that can evaluate the electrical resistance value in the crimp portion of the terminal-attached electric wire while reducing the evaluation cost as much as possible.

  The present invention has been made in view of the above-described circumstances, and its purpose is to evaluate the electrical resistance value (hereinafter referred to as “crimped portion resistance value”) of the crimped portion of the electric wire with terminal as low as possible. An object of the present invention is to provide an estimation method and an estimation device for the crimping portion resistance value.

In order to achieve the above-described object, the “method for estimating the resistance value of the crimped portion of the electric wire with terminal” according to the present invention is characterized by the following (1) to (3).
(1)
An estimation method for estimating, by simulation, a crimped portion resistance value, which is an electrical resistance value in a crimped portion of a terminal-attached wire in which a terminal is crimped to a conductor core wire of an electric wire,
A first step of simulating a crimping process for crimping the terminal to the conductor core wire;
A second step of identifying a contact point where the conductor core wire and the terminal are in contact after the crimping process;
A third step of estimating the electrical resistance value when the current is generated between the conductor core wire and the terminal through the contact location as the crimping portion resistance value,
It is an estimation method of the crimping part resistance value of the electric wire with terminal.
(2)
In the estimation method according to (1) above,
The conductor core wire is
Consists of aluminum or aluminum alloy,
The second step includes
Among the contact points, the oxide film formed on the surface of the conductor core wire is broken through the crimping process, and an adhesion point where the base material of the conductor core wire and the terminal are adhered is specified. Process,
The third step is
It is a step of estimating the electrical resistance value when the energization occurs through the adhesion point as the crimping portion resistance value.
It is an estimation method of the crimping part resistance value of the electric wire with terminal.
(3)
In the estimation method according to (2) above,
The second step includes
In the crimping process, a location where the relative movement amount when the conductor core wire and the terminal are relatively moved in a state where the conductor core wire and the terminal are in contact with each other is the adhesion location. It is a process to identify as
It is an estimation method of the crimping part resistance value of the electric wire with terminal.

  According to the estimation method of the configuration of (1) above, instead of producing a sample (actual) of a terminal-attached electric wire as in the conventional method, based on a simulation of a process of crimping a terminal on a conductor core wire, Identify the contact point with the terminal. And the electrical resistance value (in other words, electrical resistance value resulting from the contact resistance in a contact location) when an electric current flows through this contact location is estimated as a crimping | compression-bonding part resistance value. Therefore, there is no need to prepare a mold for each prototype unlike the conventional method, and the evaluation can be completed under simulation, so that the number of evaluation steps can be reduced.

  Therefore, the estimation method of this structure can evaluate the electrical resistance value (crimped part resistance value) in the crimped part of the electric wire with terminal as low as possible.

According to the estimation method of the configuration of (2) above, even when the conductor core wire uses an electric wire made of aluminum or an aluminum alloy (hereinafter referred to as “aluminum-based electric wire” for convenience), the crimping portion resistance The value can be estimated with high accuracy. Specifically, an oxide film (aluminum oxide, Al ₂ O ₃ ) due to oxygen in the atmosphere is usually formed on the surface of the conductor core wire of the aluminum-based electric wire. Since this oxide film has high insulating properties, it prevents electric conduction between the conductor core wire (base material covered with the oxide film) and the terminal.

  Therefore, in order to accurately estimate the crimped portion resistance value when using an aluminum-based electric wire, in the estimation method of this configuration, the location that actually contributes to energization among the contact locations between the conductor core wire and the terminal is specified. It has become. Specifically, in the estimation method of this configuration, the oxide film of the conductor core wire is destroyed through the crimping process, and the location where the base material of the conductor core wire and the terminal are adhered (adhesion location) is specified. It has become. This adhesion location usually corresponds to a portion of the contact locations described above. In other words, the area of the adhesion point is usually smaller (narrower) than the area of the contact point. And the electrical resistance value (electrical resistance value resulting from contact resistance) when electricity flows through this adhesion location is estimated as a crimping | compression-bonding part resistance value. Therefore, according to the estimation method of the present configuration, the resistance value of the crimping portion is accurately estimated even when an aluminum-based electric wire is used.

  According to the estimation method of the configuration of (3) above, the conductor core wire and the terminal are in contact with each other as an example of a specific method for identifying the location (adhesion location) where the oxide film of the conductor core wire is broken in the crimping process. A location where the relative movement amount (relative slippage amount) when the conductor core wire and the terminal move relative to each other in the state is greater than or equal to a predetermined threshold value is regarded as an adhesion location. Thereby, the crimping | compression-bonding part resistance value in the case of using an aluminum-type electric wire is estimated with sufficient accuracy, without requiring an excessively complicated calculation process.

Furthermore, in order to achieve the above-described object, the “apparatus for estimating the resistance of the crimped portion of the electric wire with terminal” according to the present invention is characterized by the following (4).
(4)
An estimation device that estimates a crimped portion resistance value, which is an electrical resistance value in a crimped portion of a terminal-attached electric wire with a terminal crimped to a conductor core wire of the wire, by simulation,
A first calculation unit that performs a simulation of a process of crimping the terminal to the conductor core wire;
Of the locations where the conductor core wire and the terminal are in contact after the process, the oxide film formed on the surface of the conductor core wire is destroyed through the process, whereby the base material of the conductor core wire and the terminal A second calculation unit that identifies an adhesion point where the terminal is adhered;
A third calculation unit that estimates the electrical resistance value as the crimping portion resistance value when energization occurs between the conductor core wire and the terminal via the adhesion point,
It is a device for estimating the resistance of the crimped part of the electric wire with terminal.

  According to the estimation device having the configuration of (4) above, instead of manufacturing a sample (actual) of a terminal-attached electric wire as in the conventional method, a crimping process is performed based on a simulation of a process of crimping a terminal to a conductor core wire. After that, the oxide film of the conductor core wire is destroyed, and the location where the base material of the conductor core wire and the terminal are adhered (adhesion location) is specified. And the electrical resistance value (in other words, electrical resistance value resulting from the contact resistance in an adhesion location) when an electric current flows through this adhesion location is estimated as a crimping | compression-bonding part resistance value. Therefore, there is no need to prepare a mold for each prototype unlike the conventional method, and the evaluation can be completed under simulation, so that the number of evaluation steps can be reduced.

  Furthermore, for example, when an aluminum-based electric wire is used, in consideration of the insulation property of the oxide film (aluminum oxide) formed on the surface of the conductor core wire, a location that actually contributes to energization (adhesion location. The electrical resistance value when electricity flows through this adhesion location is estimated as the crimping portion resistance value. Therefore, even if it is a case where an aluminum-type electric wire is used, a crimping | compression-bonding part resistance value is estimated accurately.

  Therefore, the estimation apparatus of this structure can evaluate the electrical resistance value (crimped part resistance value) in the crimped part of the electric wire with terminal as low as possible. Furthermore, even when an aluminum-based electric wire is used, the crimping portion resistance value is estimated with high accuracy.

  ADVANTAGE OF THE INVENTION According to this invention, the estimation method and the estimation apparatus of the crimping | compression-bonding part resistance value which can evaluate the electrical resistance value (crimping part resistance value) in the crimping part of an electric wire with a terminal as low-cost as possible can be provided.

  The present invention has been briefly described above. Further, details of the present invention will be further clarified by reading a form for carrying out the invention described below (hereinafter referred to as “embodiment”) with reference to the accompanying drawings.

FIG. 1 is a block diagram showing a hardware configuration of an apparatus for estimating a crimped portion resistance value of a terminal-attached electric wire according to an embodiment of the present invention. FIG. 2 is a diagram for explaining an outline of a method for manufacturing a terminal-attached electric wire whose crimping portion resistance value is estimated by the estimation device shown in FIG. 1, and FIG. 2 (a) is an end of the electric wire before the terminal is crimped. FIG. 2B is a perspective view of the end portion of the electric wire after crimping the terminal. FIG. 3 is a schematic diagram (a view of the end portion of the electric wire as viewed from the side) for explaining a contact location and an adhesion location between the conductor core wire and the terminal after crimping the terminal. FIG. 4 is a flowchart showing a flow of processing of a program executed by the estimation apparatus shown in FIG. 1 to estimate the crimping portion resistance value. FIG. 5 is a schematic diagram showing an example of a contact location and an adhesion location estimated in the program shown in the flowchart of FIG. FIG. 6 is a diagram for explaining an application example of the method of estimating the crimped portion resistance value of the terminal-attached electric wire using the estimation device shown in FIG. 1, and FIG. 6 (a) shows the height of the crimp portion of the terminal-attached electric wire. It is a graph which shows an example of the relationship between (crimp height) and a crimping | compression-bonding part resistance value, FIG.6 (b) is sectional drawing of the crimping part of the electric wire with a terminal for demonstrating crimp height.

<Apparatus for estimating the resistance of the crimping part>
Hereinafter, an estimation apparatus 10 according to an embodiment of the present invention will be described with reference to the drawings. The estimation apparatus 10 has an electrical resistance value (a crimping portion resistance shown in FIG. 6A) in a crimping portion of a terminal-attached electric wire (terminal-attached electric wire WT shown in FIG. 2B) whose terminal is crimped to a conductor core wire of the electric wire. It is a device that estimates the value R) by simulation.

  First, an outline of a hardware configuration of the estimation apparatus 10 will be briefly described with reference to FIG. As illustrated in FIG. 1, the estimation device 10 includes a CPU 11, a memory 12, an input unit 13, a display unit 14, and an HDD 15.

  The CPU 11 is a so-called microcomputer, and controls the estimation device 10 by executing various programs including a program (details will be described later with reference to FIG. 4) executed to estimate the crimping portion resistance value. It is supposed to be. The memory 12 is a volatile storage area, and is used as a work area for various programs to be executed.

  The input unit 13 is an input device including a mouse and a keyboard, and receives an input from a user who uses the estimation device 10. The display unit 14 is an output device such as a display. The display unit 14 sequentially displays input information from the input unit 13, a program execution status, a crimping unit resistance value estimation result, and the like.

  The HDD 15 is a so-called non-volatile storage area, and includes various programs including a program (see FIG. 4) executed to estimate the crimping portion resistance value, and various data (tables, maps, etc.) used when the program is executed. ) Is stored and memorized.

<Structure of electric wire with terminal>
Hereinafter, the terminal-attached electric wire WT will be described as an example of a target whose crimping unit resistance value is estimated by the estimation device 10 with reference to FIG. As shown in FIG. 2, the terminal-attached electric wire WT includes an electric wire 20 and a terminal 30.

  As shown in FIG. 2A, the electric wire 20 is configured to cover an outer periphery of a core wire bundle 22 in which a plurality of conductor core wires 21 are bundled with an insulating coating 23. In this example, the conductor core wire 21 is a non-plated strand made of aluminum or an aluminum alloy. In other words, the electric wire 20 is a so-called aluminum-based electric wire (aluminum electric wire or aluminum alloy electric wire).

  The terminal 30 has an electrical connection portion 31 and a crimp connection portion 32. The terminal 30 is formed by, for example, pressing a metal plate made of a conductive metal material such as copper or a copper alloy. In this example, the thickness of the terminal 30 is substantially the same at any location.

  The electrical connection portion 31 includes a flat connection plate portion 33, and a connection hole 33 a is formed in the connection plate portion 33. The connection plate part 33 is electrically connected to the terminal block, for example, by inserting a fastening bolt into the connection hole 33a and fastening it to the terminal block of the connection device.

  The crimping connection part 32 has a conductor crimping part 34 and a jacket crimping part 35 in this order from the electrical connection part 31 side. The conductor crimping part 34 has a base part 36 and a pair of conductor crimping pieces 37 formed on both sides of the base part 36. The core wire bundle 22 is placed on the base portion 36. The conductor crimping piece 37 extends from the base portion 36 so as to sandwich the core wire bundle 22. Serrations (unevenness, not shown) are formed on the inner wall surface of the conductor crimping portion 34. The conductor crimping portion 34 crimps the core wire bundle 22 of the electric wire 20 by curving (clamping) the pair of conductor crimping pieces 37 inward. Thereby, the terminal 30 is conductively connected to the core wire bundle 22 of the electric wire 20.

  The jacket crimping part 35 includes a base part 38 and a pair of jacket crimping pieces 39 formed on both sides of the base part 38. A base portion 38 of the outer cover crimping portion 35 extends from the base portion 36 of the conductor crimping portion 34. The insulating coating 23 of the electric wire 20 is placed on the base portion 38. The outer cover crimping piece 39 extends from the base portion 38 so as to sandwich the insulating coating 23 portion of the electric wire 20. The outer jacket crimping portion 35 bends (clamps) the pair of outer jacket crimping pieces 39 inward, thereby crimping and fixing the portion of the insulating coating 23 of the electric wire 20.

  More specifically, the terminal-attached electric wire WT (actual) is manufactured according to the following procedure.

  First, as shown in FIG. 2A, the insulation coating 23 at the end of the electric wire 20 is peeled off, and the core wire bundle 22 in which the conductor core wires 21 are bundled is exposed for a predetermined length. The predetermined length of the core wire bundle 22 to be exposed may be a length sufficient to crimp the terminal 30.

  Next, the terminal 30 is crimped to the core wire bundle 22 as shown in FIG. 2B by using a terminal crimping machine (a general apparatus having a crimping mechanism using an anvil and a crimper, not shown). Specifically, the terminal 30 is placed on the support surface of the anvil (not shown) of the terminal crimping machine, and the crimper (illustrated) is disposed above the anvil in a state where the end of the electric wire 20 is disposed on the terminal 30. (Omitted) is lowered. Then, the conductor crimping pieces 37 are pressed toward each other by the arch grooves of the crimper and bent inward, and the conductor crimping part 34 is sandwiched between the anvil and the crimper and pressed against the core wire bundle 22 (clamping). With these processes, the terminal-attached electric wire WT as shown in FIG. 2B is manufactured.

  In the electric wire WT with a terminal, as shown in FIG. 6B described later, the base portion 36 and the conductor crimping piece 37 of the conductor crimping portion 34 are crimped to the core wire bundle 22, and the conductor crimping portion 34 (that is, the terminal 30) is formed. The core wire bundle 22 is electrically connected (conducted). Prior to the terminal crimping, the core wire bundle 22 may be subjected to an ultrasonic bonding process, and the terminal 30 may be crimped to the core wire bundle 22 that has been subjected to the ultrasonic bonding process.

  In the electric wire WT with a terminal, a portion (core wire bundle 22 (conductor core wire 21) of the electric wire 20) and a conductor crimping portion 34 (= base portion 36 + conductor crimping piece 37) of the terminal 30 are contributed to the crimping of the terminal 30. For convenience, the “including portion” is referred to as a “crimping portion 40”.

  Note that the outer cover crimping piece 39 of the terminal 30 is also crimped by a jacket anvil and a crimper (not shown) provided in the terminal crimping machine. As a result, the outer cover crimping portion 35 of the terminal 30 crimps and fixes the insulating coating 23 of the electric wire 20.

  By the way, from the viewpoint of improving the electrical characteristics of the terminal-attached electric wire WT, it is important to evaluate the magnitude of the voltage drop (electric resistance value in the crimping portion 40) generated in the crimping portion 40 after terminal crimping. Hereinafter, the electrical resistance value in the crimping part 40 is referred to as “crimping part resistance value”. Specifically, the resistance value of the crimping portion is determined by contact (or adhesion) between the core wire bundle 22 (conductor core wire 21) of the electric wire 20 and the conductor crimping portion 34 (= base portion 36 + conductor crimping piece 37) of the terminal 30. It can also be said to be a value of contact resistance (electric resistance existing in the vicinity of the interface between two conductors) at a certain location.

<Method for estimating the crimping portion resistance value>
Hereinafter, a method of estimating the crimped portion resistance value by the estimation device 10 will be described with reference to FIGS.

  In order to estimate the crimping portion resistance value, a place where energization can occur between the core wire bundle 22 of the electric wire 20 and the conductor crimping portion 34 of the terminal 30 (in other words, contact between the core wire bundle 22 and the conductor crimping portion 34). It is necessary to specify location A). In FIG. 3, this contact point A is schematically shown (refer to the area indicated by hatching).

Here, when the electric wire 20 is an aluminum-type electric wire, an oxide film (aluminum oxide, Al ₂ O ₃ ) is usually formed on the surface of the core wire bundle 22 (conductor core wire 21). Since this oxide film has high insulating properties, it prevents electric conduction between the core wire bundle 22 (the base material of the conductor core wire 21) and the terminal 30. Therefore, in the case of using an aluminum-based electric wire such as the electric wire WT with a terminal, in order to accurately estimate the crimping portion resistance value, the contact portion A between the core wire bundle 22 and the conductor crimping portion 34 actually contributes to energization. It is preferable to specify the location (adhesion location B). Specifically, at the adhesion location B, the oxide film formed on the surface of the core wire bundle 22 is destroyed through the process of pressure bonding, and the base material of the conductor core wire 21 and the conductor pressure bonding portion 34 are adhered. It is a place. In FIG. 3, this adhesion point B is also schematically shown (see the area indicated by the crossed diagonal lines).

  In addition to the contact location A (or in place of the contact location A if the specification of the contact location A can be omitted), the estimation apparatus 10 identifies the adhesion location B. And the estimation apparatus 10 estimates the electrical resistance value (electrical resistance value resulting from contact resistance) when electricity flows through this adhesion location B as a crimping | compression-bonding part resistance value R. FIG.

  Specifically, the CPU 11 of the estimation device 10 estimates the crimping portion resistance value R by executing a routine (program) shown in the flowchart of FIG. This program is stored in the HDD 15 (see FIG. 1). The processing of this program is started when the user inputs an instruction to start the crimping portion resistance value R estimation processing to the input unit 13.

  When the processing of this program is started, data relating to various specifications such as the shape and material of the core wire bundle 22 of the electric wire 20 is input to the CPU 11 in step S1 of FIG. The shape of the input core wire bundle 22 is divided into meshes. This input is performed via the input unit 13.

  Next, in step S <b> 2, data relating to various specifications such as the shape and material of the terminal 30 is input to the CPU 11. The shape of the input terminal 30 is divided into meshes. This input is also performed via the input unit 13.

  Next, in step S3, a simulation (crimping simulation) of a crimping process for crimping the terminal 30 to the conductor core wire 21 (core wire bundle 22) of the electric wire 20 is executed. In the crimping simulation, the core wire bundle is based on various data input by the execution of steps S1 and S2 and various data (including anvil and crimper shapes and materials) related to the terminal crimping machine stored in advance in the HDD 15. For example, the deformation behavior and the pressing state of the crimping part 40 in the process of the crimping process for crimping the conductor crimping part 34 to 22 are simulated in time series for each divided micro area.

  By executing this crimping simulation, in addition to estimating the shape and pressing state (contact state) of the crimping part 40 after the crimping process is completed, the core wire bundle 22 and the conductor crimping part 34 are in the process of the crimping process. A relative movement amount (relative slip amount) or the like in the case of relatively moving while maintaining the contact state can also be estimated. This crimping simulation can be realized by using, for example, a well-known finite element method (FEM).

  Next, in step S4, the contact location A (see FIG. 3) after the completion of the crimping process is specified based on the result of the crimping simulation. Specifically, the contact location A can be specified as a location where the conductor crimping portion 34 is pressed against the core wire bundle 22 after the crimping process is completed (contact pressure becomes a positive value).

  Next, in step S5, an adhesion point B (see FIG. 3) after the completion of the crimping process is specified based on the result of the crimping simulation. Specifically, the adhesion location B is a state in which the core wire bundle 22 and the conductor crimping portion 34 are in contact with each other in the process of crimping among the contact locations A identified in step S4 (a state where the contact pressure is positive). The relative movement amount (relative slip amount) moved relatively while maintaining the above can be specified as a location where the value is equal to or greater than a predetermined threshold.

  Here, the reason for specifying the location where the relative movement amount is equal to or greater than the threshold value as the adhesion location B is that the core wire bundle 22 and the conductor crimping portion 34 are kept in contact with each other in the process of the crimping process. The oxide film (aluminum oxide) formed on the surface of the core wire bundle 22 (conductor core wire 21) is destroyed by friction between the core wire bundle 22 and the conductor crimp portion 34, and the base material of the conductor core wire 21 and the conductor crimp portion 34 are This is because it is considered that adhesion occurs between them. Note that the threshold used in this case can be appropriately determined by conducting various experiments in advance.

  FIG. 5 is a schematic diagram illustrating an example of the contact location A and the adhesion location B identified by Step S4 and Step S5. In FIG. 5, the region surrounded by the alternate long and short dash line corresponds to the crimping portion 40 in FIG. 3 (the portion where the conductor crimping portion 34 is crimped to the core wire bundle 22). In FIG. 5, the contact location A is shown in light gray, and the adhesion location B is shown in dark gray. As shown in FIG. 5, in this example, the adhesion point B corresponds to a part of the contact point A, and the area of the adhesion point B is smaller (narrower) than the area of the contact point A. In addition, it is thought that the ring-shaped adhesion part B in the center area | region of the crimping | compression-bonding part 40 originates in the serration (unevenness | corrugation) formed in the inner wall face of the conductor crimping | compression-bonding part 34. FIG.

  Next, in step S6, the area S of the adhesion point B specified in step S5 is calculated. This area S can be calculated as the sum of the areas of the microregions identified as the adhesion points B.

  Next, in step S7, the crimping portion resistance value R is estimated based on the area S of the adhesion point B calculated in step S6. The crimping portion resistance value R is calculated by numerically calculating an energization current and a voltage drop according to the area S by the CPU 11. In this example, the crimping portion resistance value R is calculated so as to decrease in inverse proportion to the increase in the area S. When the process of step S7 is completed, the process of this program ends.

  By the above processing, the crimping portion resistance value R in the crimping portion 40 is estimated based on the simulation of the crimping process of the terminal-attached electric wire WT.

<Practical example>
Hereinafter, an example in which the estimation apparatus 10 and the estimation method described above are put into practical use will be described with reference to FIG.

  6A repeats the process (crimping simulation) shown in FIG. 4 while changing the height of the crimping portion 40 (crimp height CH shown in FIG. 6B) after the crimping process of the electric wire WT with terminal is completed. An example of “relation between crimp height CH and crimping portion resistance value R” obtained by execution is shown.

  The crimp height CH in the crimping simulation can be changed by changing the relative positions of the anvil and the crimper among various data related to the terminal crimping machine stored in advance in the HDD 15. In addition, as the crimp height CH is larger, the degree of crimping of the crimping part 40 after the crimping process is completed is smaller (low compression), and as the crimp height CH is smaller, the degree of crimping of the crimping part 40 after the crimping process is completed. It will be big (high compression).

  In the example shown in FIG. 6A, the estimated crimped portion resistance value R (vertical axis of the graph) is relatively less than the reference value Rth when the crimp height CH (horizontal axis of the graph) is less than or equal to the predetermined value CHth. It changes at a small, almost constant value and starts to rise when the crimp height CH approaches the predetermined value CHth, reaches the reference value Rth when the crimp height CH is the predetermined value CHth, and the crimp height CH exceeds the predetermined value CHth. And a relatively large value exceeding the reference value Rth.

  Therefore, for example, the reference value Rth is determined based on the electrical characteristics required for the terminal-attached electric wire WT, and the crimping portion resistance value R calculated (estimated) using the estimation method by the estimation device 10 is the reference value Rth. It is conceivable to set the specifications of the electric wire 20 and the terminal 30 and the specifications of the terminal crimping machine (not shown) so as not to exceed. If a terminal-attached electric wire WT (actual product) is actually manufactured according to the specifications set in this way, the required electrical characteristics can be obtained without manufacturing a large number of samples (prototypes) as in the conventional method described above. The terminal-attached electric wire WT that satisfies the characteristics can be manufactured. The estimation device 10 and the estimation method can be practically used in this way, for example.

  By the way, the transition of the crimped portion resistance value R shown in FIG. 6A can be explained by the fact that the area S of the adhesion point B is small (or large) when the crimp height CH is large (or small). In a normal terminal crimping machine, the thickness of the crimping portion 40 (crimp height CH) changes greatly before and after crimping, but the width of the crimping portion 40 does not substantially change. Therefore, in evaluating the crimping portion resistance value R, the importance of the thickness (crimp height CH) of the crimping portion 40 is high. Therefore, in the example shown in FIG. 6A, only the thickness of the crimping portion 40 (crimp height CH) is considered, and the width of the crimping portion 40 is not considered.

  In addition, according to the comparative test etc. which the inventor performed using the electric wire (real thing) with an actual terminal, the estimation result of the crimping | compression-bonding part resistance value R by the estimation apparatus 10 shown to Fig.6 (a), and an actual terminal It has been confirmed that the measurement results (relationship between the crimp height CH and the crimped portion resistance value R) using the electric wire (actual) coincide with a practically sufficient level.

<Action and effect>
As described above, according to the estimation device 10 and the estimation method (see the flowchart of FIG. 4) according to the embodiment of the present invention, instead of manufacturing a sample (actual) of a terminal-attached wire as in the conventional method, The conductor crimping portion 34 of the terminal 30 is crimped to the core wire bundle 22 and formed on the surface of the core wire bundle 22 in the contact portion A (see FIG. 3) between the core wire bundle 22 and the conductor crimping portion 34. The adhesion point B where the base material of the conductor core wire 21 and the conductor crimping part 34 adhere is specified by the oxide film being destroyed through the process of crimping. And the electrical resistance value (contact resistance value) at the time of energizing this adhesion location B is estimated as the crimping portion resistance value R.

As a result, there is no need to prepare a mold for each prototype as in the conventional method, and the evaluation can be completed under simulation, thereby reducing the number of evaluation steps. Further, even when an aluminum-based electric wire in which an oxide film (aluminum oxide, Al ₂ O ₃ ) is easily formed on the surface is used as the core wire bundle 22 (conductor core wire 21), the crimping portion resistance value R is accurately estimated. obtain.

  Therefore, according to the estimation apparatus 10 and the estimation method (FIG. 4) described above, the electrical resistance value (crimped portion resistance value R) in the crimped portion 40 of the terminal-attached electric wire WT can be evaluated as low as possible. Furthermore, even when an aluminum-based electric wire is used, the crimping portion resistance value R can be estimated with high accuracy.

<Other aspects>
In addition, this invention is not limited to said each embodiment, A various modification is employable within the scope of the present invention. For example, the present invention is not limited to the above-described embodiments, and modifications, improvements, and the like can be made as appropriate. In addition, the material, shape, dimensions, number, arrangement location, and the like of each component in the above-described embodiment are arbitrary and are not limited as long as the present invention can be achieved.

  For example, in the estimation apparatus 10 and the estimation method according to the above-described embodiment, in consideration of the insulating property of the oxide film (aluminum oxide) formed on the surface of the conductor core wire 21 (core wire bundle 22), it actually contributes to energization. The location (adhesion location B) is specified, and the electrical resistance value (contact resistance value) when energization occurs through the adhesion location B is estimated as the crimping portion resistance value R.

  However, an electric wire (for example, an electric wire having a conductor core wire 21 made of copper or a copper alloy, so-called a copper wire) that does not need to dare to consider the insulation of the oxide film formed on the surface of the conductor core wire 21 as the electric wire 20. When using, only the contact location A may be specified, and the electrical resistance value (contact resistance value) when energization occurs through the contact location A may be estimated as the crimping portion resistance value R. In this case, in the flowchart shown in FIG. 4, step S5 may be omitted, and the estimation method may be configured so that the area S of the contact location A is calculated instead of the adhesion location B in step S6.

  Furthermore, in the said embodiment, the adhesion location B is determined by the magnitude of the relative movement amount (relative slippage amount) between the conductor core wire 21 (core wire bundle 22) and the terminal 30 (conductor crimp portion 34) based on the crimping simulation. It is specified (estimated) (step S6 in FIG. 4). However, identification (estimation) of the adhesion site B can be performed by a method different from this method.

  Specifically, for example, the depth of the wear scar generated by the friction between the conductor core wire 21 and the terminal 30 is calculated based on the crimping simulation, and the adhesion point B is specified (estimated) based on the depth of the wear scar. ) Further, for example, the adhesion location B may be specified (estimated) based on the magnitude of deformation (distortion) occurring in the conductor core wire 21. In addition, we actually manufactured, disassembled and analyzed some samples of electric wires with terminals (various specifications), measured the area of adhesion for each specification and degree of compression, You may identify (estimate) the adhesion location B of the electric wire with a terminal which has specific specifications using measured value (graph etc.).

  In addition, in the said embodiment, the area S of the adhesion location B of the electric wire WT with a terminal is calculated internally. However, if necessary, the adhesion location B of the terminal-attached electric wire WT is visualized by mapping the adhesion location B on the image of the conductor core wire 21 (core wire bundle 22) after crimping and displaying it on the display unit 14. May be.

Here, the characteristics of the embodiments of the “method for estimating the crimping portion resistance value of the electric wire with terminal” and the “estimating device for the crimping portion resistance value of the electric wire with terminal” according to the present invention described above are respectively (1) to (4). ) Briefly listed.
(1)
A crimping portion resistance value (R) that is an electrical resistance value in the crimping portion (40) of the terminal-attached electric wire (WT) in which the terminal (30) is crimped to the conductor core wire (21) of the electric wire (20) is estimated by simulation. An estimation method (FIG. 4),
A first step (S3 in FIG. 4) for simulating a crimping process of crimping the terminal (30) to the conductor core wire (21);
A second step (S4, S5 in FIG. 4) for identifying a contact location (A) where the conductor core wire and the terminal are in contact after the crimping process;
A third step (S6 in FIG. 4) for estimating the electrical resistance value when the energization occurs between the conductor core wire and the terminal through the contact location (A) as the crimping portion resistance value (R). S7), and
A method of estimating the resistance value of the crimped portion of the electric wire with terminal.
(2)
In the estimation method according to (1) above,
The conductor core wire (21) is
Consists of aluminum or aluminum alloy,
The second step (S4, S5 in FIG. 4)
Among the contact locations (A), the oxide film formed on the surface of the conductor core wire (21) is destroyed through the crimping process, and the base material of the conductor core wire and the terminal (30) adhere to each other. It is a step (S5) for specifying the adhesion point (B),
The third step (S6, S7 in FIG. 4)
It is a step (S7) of estimating the electric resistance value when the energization occurs through the adhesion point (B) as the crimping portion resistance value (R).
A method of estimating the resistance value of the crimped portion of the electric wire with terminal.
(3)
In the estimation method according to (2) above,
The second step includes
In the crimping process, a location where a relative movement amount when the conductor core wire and the terminal are relatively moved in a state where the conductor core wire (21) and the terminal (30) are in contact is a predetermined threshold value or more Is a step (S5 in FIG. 4) that identifies the adhesion location (B).
A method of estimating the resistance value of the crimped portion of the electric wire with terminal.
(4)
A crimping portion resistance value (R) that is an electrical resistance value in the crimping portion (40) of the terminal-attached electric wire (WT) in which the terminal (30) is crimped to the conductor core wire (21) of the electric wire (20) is estimated by simulation. An estimation device (10) comprising:
A first calculation unit (11, S3 in FIG. 4) that performs a simulation of a crimping process of crimping the terminal (30) to the conductor core wire (21);
Of the locations where the conductor core wire (21) and the terminal (30) are in contact after the crimping process, the oxide film formed on the surface of the conductor core wire is destroyed through the crimping process and the A second calculation unit (11, S4, S5 in FIG. 4) for specifying an adhesion point (B) where the base material of the conductor core wire and the terminal are adhered;
A third arithmetic unit (11, FIG. 11) that estimates the electrical resistance value as the crimping portion resistance value (R) when energization occurs between the conductor core wire and the terminal via the adhesion location (B). 4 S6, S7),
A device for estimating the resistance of a crimped part of a terminal-attached electric wire.

WT electric wire with terminal 10 estimation device 20 electric wire 21 conductor core wire 22 core wire bundle 30 terminal 40 crimping part

Claims (4)

An estimation method for estimating, by simulation, a crimped portion resistance value, which is an electrical resistance value in a crimped portion of a terminal-attached wire in which a terminal is crimped to a conductor core wire of an electric wire,
A first step of simulating a crimping process for crimping the terminal to the conductor core wire;
A second step of identifying a contact point where the conductor core wire and the terminal are in contact after the crimping process;
A third step of estimating the electrical resistance value when the current is generated between the conductor core wire and the terminal through the contact location as the crimping portion resistance value,
A method of estimating the resistance value of the crimped portion of the electric wire with terminal. The estimation method according to claim 1,
The conductor core wire is
Consists of aluminum or aluminum alloy,
The second step includes
Among the contact points, the oxide film formed on the surface of the conductor core wire is broken through the crimping process, and an adhesion point where the base material of the conductor core wire and the terminal are adhered is specified. Process,
The third step is
It is a step of estimating the electrical resistance value when the energization occurs through the adhesion point as the crimping portion resistance value.
A method of estimating the resistance value of the crimped portion of the electric wire with terminal. The estimation method according to claim 2,
The second step includes
In the crimping process, a location where the relative movement amount when the conductor core wire and the terminal are relatively moved in a state where the conductor core wire and the terminal are in contact with each other is the adhesion location. It is a process to identify as
A method of estimating the resistance value of the crimped portion of the electric wire with terminal. An estimation device that estimates a crimped portion resistance value, which is an electrical resistance value in a crimped portion of a terminal-attached electric wire with a terminal crimped to a conductor core wire of the wire, by simulation,
A first calculation unit that performs a simulation of a crimping process for crimping the terminal to the conductor core wire;
Of the locations where the conductor core wire and the terminal are in contact with each other after the crimping process, the oxide film formed on the surface of the conductor core wire is destroyed through the crimping process and the base material of the conductor core wire A second calculation unit that identifies an adhesion point where the terminal is adhered;
A third computation unit that estimates the electrical resistance value as the crimping portion resistance value when energization occurs between the conductor core wire and the terminal through the adhesion point,
A device for estimating the resistance of a crimped part of a terminal-attached electric wire.