JP5123001B2 - Contact performance coefficient calculation device and contact performance coefficient calculation method - Google Patents

Description

  The present invention relates to a contact performance coefficient calculation device and a contact performance coefficient calculation method, and in particular, calculates a contact performance coefficient corresponding to a contact resistance between a caulking piece provided on a terminal fitting and a core wire caulked on the caulking piece. The present invention relates to a contact performance coefficient calculation device and a contact performance coefficient calculation method.

  Conventionally, as a method of electrically connecting a core wire of a conducting wire and a terminal fitting, for example, there is a method of crimping and crimping a core wire with a caulking piece provided on the terminal fitting (for example, Patent Documents 1 to 3). ). The terminal fitting used for this crimp connection is generally configured as shown in FIG. As shown in the figure, the terminal fitting 1 includes a caulking piece 2. Then, the crimping piece 2 and the core wire 3 of the terminal fitting 1 are sandwiched between the crimper 4 (upper mold) and the anvil 5 (lower mold) as shown in FIGS. 7B and 7C, and then the pressure is applied. By adding, the core wire 3 is crimped and crimped by the caulking piece 2, and the terminal fitting 1 and the core wire 3 are electrically and mechanically connected as shown in FIG.

  By the way, the relationship between the crimp height C / H after crimping (see FIG. 7D) and the fixing force F or contact resistance R between the terminal fitting 1 and the core wire 3 after crimping is shown in FIG. It becomes like this. As shown in the figure, since the fixing force F has a non-linear characteristic that is convex upward with respect to the crimp height C / H, the crimp height C / H can be used for a certain range. Will exist. Similarly, there is a contact resistance R that can be used with respect to the crimp height C / H. From the relationship between the fixing force F having such non-linear characteristics and the contact resistance R, the range of the crimp height C / H that can be used for both the fixing force F and the contact resistance R (the “optimal crimp height shown in FIG. 8”). ") Will be limited.

  Therefore, conventionally, for example, when designing a new connection, the terminal fitting 1, the core wire 3, the crimper 4 or the anvil 5 are designed. Then, after actually performing the crimping connection using the designed terminal fitting 1, core wire 3, crimper 4 or anvil 5, etc., the fixing force F, the contact resistance R, etc. are measured to obtain the optimum fixing force. F and evaluation of whether or not the contact resistance R is obtained are executed. If not obtained, the terminal fitting 1, the core wire 3, the crimper 4 or the anvil 5 is newly designed, and then the above is repeated.

By the way, it is known that the contact resistance R described above increases when left in a low temperature environment or a high temperature environment. Therefore, the measurement of the contact resistance R has been performed after, for example, a cold collision test in which a low temperature environment of −40 ° C. and a high temperature environment of + 120 ° C. are alternately repeated 1000 times. If one cycle of the low temperature environment and the high temperature environment requires 2 hours, 2000 hours are required until the contact resistance R is measured. That is, in the conventional connection design of the terminal fitting 1 to the core wire 3, it is necessary to obtain an appropriate one by repeating the cut-and-try process as described above: design → actual connection → cooling collision test → evaluation (measurement). For this reason, if the person who has little design experience performs the connection design described above, there is a problem that a lot of time is wasted until the desired product is obtained, and the design period becomes longer and the design cost increases. there were.
JP 2007-173215 A JP 2006-351451 A Japanese Patent Laid-Open No. 10-50449

  Therefore, the present invention pays attention to the problems as described above so that anyone can easily and quickly perform the connection design between the terminal fitting and the core wire without being influenced by the experience of the designer. It is an object of the present invention to provide a contact performance coefficient calculation device and a contact performance coefficient calculation method for calculating a contact performance coefficient corresponding to a contact resistance by simulation so that they can be supported.

Ｌ_k＝（Ｌ_k+1＋Ｌ_k-1）／２ …（２） As a result of repeated investigations to obtain a contact performance coefficient calculation device and a contact performance coefficient calculation method for calculating the contact performance coefficient according to the contact resistance by simulation without being influenced by the experience of the designer, The contact performance coefficient CC shown in the formulas (1) and (2) is found to be a value corresponding to the contact resistance R, and the present invention has been completed.

L _k = (L _{k + 1} + L _k-1 ) / 2 (2)

As shown in FIG. 4B, _PSK is a node that contacts the crimped piece model 2m among the nodes on the contour of the core wire model 3m after crimping (after crimping) obtained by executing the finite element method. N _SK is the force acting on the caulking piece model 2m. L k _{+ 1} sections N _SK, and a distance between the node N _{k + 1} adjacent to the inner section N _SK sections on the contour of the core wire model 3m, L _k-1 sections N _SK and the core wire model 3m This is the distance from the node N _k-1 adjacent to the node N _SK among the nodes on the contour of the. n is the total number of nodes N _SK contacting the crimping pieces model 2m of sections on the contour of the core wire model 3m.

That is, the invention according to claim 1 is a contact performance coefficient calculation device that calculates a contact performance coefficient according to the contact resistance between the crimped piece provided on the terminal fitting and the core wire crimped on the crimped piece, A core wire model acquisition means for acquiring a core wire model obtained by dividing a cross section of the core wire into a plurality of elements; a crimping piece model acquisition means for acquiring a caulking piece model obtained by dividing the cross section of the caulking piece into a plurality of elements; Deformation calculating means for calculating, by a finite element method, the displacement of each node constituting the core wire model after the core wire is caulked by the caulking piece and the force acting on each node and the force acting on each node after being sandwiched between lower molds And a node extracting means for extracting a node that contacts the caulking piece model from the nodes on the contour of the core model after the caulking from the displacement of each node calculated by the deformation calculating means; A first node between one of a pair of nodes adjacent to the node extracted by the node extraction unit among the nodes extracted by the node extraction unit and the nodes on the contour of the core model after the caulking The first distance calculating means for obtaining the distance, the node extracted by the node extracting means, and the node extracted by the node extracting means among the nodes on the outline of the core model after the caulking Half of the sum of the second distance calculating means for obtaining the second distance between the other of the pair of nodes, the first distance, and the second distance is extracted by the node extracting means. The contact length calculation means obtained as the contact length of the nodes, the contact lengths obtained for all the nodes extracted by the node extraction means, and the nodes extracted by the node extraction means act on the caulking piece model. Find the sum of the values multiplied by the force The contact performance coefficient calculating means for calculating the reciprocal of the sum as the contact of merit, lies in contact performance coefficient calculation apparatus characterized by comprising a.

The invention according to claim 2 uses a computer that performs various processes in accordance with a processing program , and calculates a contact performance coefficient according to the contact resistance between a crimped piece provided on the terminal fitting and a core wire crimped on the crimped piece. A calculation method for a contact performance coefficient to be calculated, wherein the computer acquires a core wire model in which a cross section of the core wire is divided into a plurality of elements, and a caulking piece model in which a cross section of the caulking piece is divided into a plurality of elements. Steps, displacement of each node constituting the caulking piece model after the caulking piece is caulked with the caulking piece sandwiched between the upper die and the lower die, and force acting on each node a step of calculating by the finite element method, the computer, the crimping of the sections on the contour of the core wire model after the caulking from the displacement of each node of the calculated A step of extracting the section in contact with the model, the computer, the extracted section and a pair of nodes adjacent to the extracted section of the sections on the contour of the core wire model after the caulking On the other hand, a step of obtaining a first distance between the pair of the computer and the computer adjacent to the extracted node among the extracted nodes and the nodes on the outline of the core model after the caulking A step of obtaining a second distance between the other of the nodes, and the computer uses 1/2 of the sum of the first distance and the second distance as the contact length of the extracted node a step of determining, the computer, the contact length and the extracted sections obtained for all clauses of the extracted is the total sum of values obtained by multiplying the force acting on the crimping pieces model, of the total Let the reciprocal be the contact performance coefficient. Be carried out a step of determining, successively resides in contact performance coefficient calculation method according to claim.

  As described above, according to the first and second aspects of the invention, since the contact performance coefficient corresponding to the contact resistance can be calculated by simulation, the terminal fitting and the core wire are not affected by the experience of the designer. Can be designed so that anyone can easily and quickly design connections.

  Hereinafter, a contact performance coefficient calculation apparatus and a contact performance coefficient calculation method according to the present invention will be described with reference to the drawings. The contact performance coefficient calculation device 6 shown in FIG. 1 is constituted by a personal computer, for example, and when the terminal fitting 1 and the core wire 3 are connected by crimping, the terminal fitting 1-core wire 3 prior to the actual crimping connection. This is a device for calculating a contact performance coefficient CC according to the contact resistance R between the two.

  As shown in the figure, the contact performance coefficient calculation device 6 includes an input device 7, a display device 8, and a microcomputer (hereinafter referred to as μCOM 9). The input device 7 is composed of operation means such as a keyboard and a mouse, for example, and includes information on the shape of the crimping piece 2, the core wire 3, the crimper 4 and the anvil 5 of the terminal fitting 1 described in the prior art, and the crimping piece 2 and This is a device for inputting material property information which is a stress-strain property of the material of the core wire 3. As the shape information, for example, CAD data of the caulking piece 2, the core wire 3, the crimper 4, and the anvil 5 created by CAD can be considered.

  The display device 8 is a device for displaying, for example, the calculated contact performance coefficient. The μCOM 9 controls the entire contact performance coefficient calculation device 6 and performs a central processing unit (hereinafter referred to as CPU) 10 that performs various processes according to a processing program, and a ROM 11 that is a read-only memory that stores a program for processing performed by the CPU 10 and the like. And a RAM 12 which is a readable / writable memory having a work area used in various processing steps in the CPU 10 and a data storage area for storing various data.

  Next, the operation of the contact performance coefficient calculation device 6 having the above-described configuration will be described below with reference to FIGS. First, when an analysis simulation process start operation is performed by the input device 7, the CPU 10 starts the analysis simulation process. First, the CPU 10 displays on the display device 8 an input screen for inputting the shape information of the crimping piece 2, the core wire 3, the crimper 4 and the anvil 5 of the terminal fitting 1 and the material characteristic information of the crimping piece 2 and the core wire 3. An input process for display is performed (step S1 in FIG. 2).

  The user operates the operation means such as the keyboard and mouse of the input device 7 in accordance with the display on the display device 8 to input the shape information and material property information. The shape information and material characteristics according to the types A, B, C,... Of the terminal fitting 1, the types A, B, C,... Of the core wire 3, and the types A, B, C,. Information may be recorded in the ROM 11 in advance, and the user may be allowed to input the shape information and material information by selecting the types of the terminal fitting 1, the core wire 3, the crimper type crimper 4 and the anvil 5. .

  Thereafter, the CPU 10 performs a finite element model conversion process (step S2). In the finite element model conversion processing, as shown in FIG. 3A, the CPU 10 converts the crimped piece 2 and the core wire 3 input by the input processing into a crimped piece model 2m and a core wire model 3m, each of which is divided into a plurality of elements. To do. In this finite element model conversion process, the CPU 10 functions as a core wire model acquisition unit and a caulking piece model acquisition unit in the claims.

  Next, the CPU 10 performs a deformation calculation process (step S3). In the deformation calculation process, as shown in FIGS. 3B to 3D, the CPU 10 crimps the core wire 3 with the caulking piece 2 after being crimped between the crimper 4 and the anvil 5 using the finite element method. The displacement of each node N constituting the core wire model 3m and the caulking piece model 2m after the load applied to the caulking piece 2 and the core wire 3 is released by separating the anvil 5 and the force P acting on each node N are calculated. To do. In this deformation calculation process, the CPU 10 functions as deformation calculation means in the claims.

  When the crimper 4 and the anvil 5 are brought close to each other and the crimping piece 2 is caulked and then the crimper 4 and the anvil 5 are separated and the load applied to the caulking piece 2 and the core wire 3 is unloaded, the caulking piece 2 and the core wire 3 are spring-backed. This causes an elastic recovery phenomenon called. Therefore, the deformation calculation process can calculate the displacement of each node N and the force P acting on each node N constituting the core model 3m and the caulking piece model 2m after the spring back.

  Thereafter, the CPU 10 executes steps S4 to S6, and responds to the contact resistance R between the caulking piece 2 and the core wire 3 from the displacement of each node N obtained by the deformation calculation process and the force P acting on each node N. A contact performance coefficient CC described later is obtained. The contact resistance R decreases as the contact area and contact pressure between the caulking piece 2 and the core wire 3 increase. Therefore, the CPU 10 executes the following steps S4 and S5 to obtain the contact length between the caulking piece 2 and the core wire 3 on the cross section as shown in FIG. 3 as a value corresponding to the contact area.

That is, the CPU 10 functions as a node extracting means, and the node N that contacts the caulking piece model 2m among the nodes N on the contour of the core model 3m after the spring back from the displacement of each node N calculated by the deformation calculation process described above. A node extraction process for extracting _S is performed (step S4). The results are shown in FIG. As shown in the figure, as a result of the clause extraction process, for example, Total n-number of nodes N _S are extracted. Incidentally, FIG. 4 P _S in (A) the force acting on the node N _S on the core wire model 3m extracted in step S4, i.e., the crimping pieces 2 model from node N _S on the core wire model 3m extracted in step S4 The contact pressure acting on is shown. Then, CPU 10 has the first distance calculating unit, the second distance calculating means, serves as a contact length calculating unit, a crimping piece 2 and the core wire 3 after the spring-back at each node N _S extracted by clause extraction process The contact length calculation process for obtaining the contact length is performed (step S5). As shown in FIG. 4B, the caulking piece model 2m and the core wire model 3m are in contact with each other at a point (node). However, the present inventor actually made an arbitrary node N _Sk extracted in step S4. Therefore, it is assumed that the contact is made with the contact length L _k shown by the following formula (2).
L _k = (L _{k + 1} + L _k-1 ) / 2 (2)

Note that L _{k + 1} is the distance (first distance) between any extracted node N _Sk and node N _{k + 1} . The node N _{k + 1} is _one of a pair of nodes N _{k + 1} and N _k−1 adjacent to the node N _Sk among the nodes N on the outline of the core wire model 3m. L _k-1 is a distance (second distance) between the extracted arbitrary nodes N _Sk and N _k-1 . The node N _k-1 is the other of the pair of nodes N _{k + 1} and N _k-1 adjacent to the node N _Sk among the nodes N on the outline of the core wire model 3m.

Next, the CPU 10 functions as a contact performance coefficient calculation means, and as shown in the following equation (1), the contact length L _k obtained for all the nodes N _S extracted in step S4, that is, the total number of nodes _NS. a node N _S extracted in step S4 is the total sum of values obtained by multiplying the contact pressure P _SK acting on crimping pieces model 2m, contact performance coefficient calculation process for obtaining the reciprocal of the sum as the contact performance coefficient CC After that (step S6), the calculated contact performance coefficient CC is displayed on the display device 8 (step 7), and the analysis simulation process is terminated.

As apparent from the equation (1), the contact performance coefficient CC decreases as the contact length (area) L _k between the caulking piece 2 and the core wire 3 and the contact pressure P _Sk increase as in the case of the contact resistance R. Is a coefficient. That is, the present inventor assumed that the contact performance coefficient CC shown in the above formula (1) would be a value corresponding to the contact resistance R.

  Next, the inventor of the present invention calculates the contact performance coefficient CC calculated using the product of the present invention described above for the sample products (1) to (5) shown in FIG. 5 and the sample products (1) to (5) shown in FIG. Comparison was made with the contact resistance R measured after actually making a prototype of (5) and executing the thermal collision test. The results are shown in FIG. Sample product (1) is a product in which core wire 3 is crimped with crimping piece 2 of terminal metal fitting 1 using type A core wire 3, type A terminal metal fitting 1, type A crimping type (crimper 4, anvil 5). It is. Similarly, the sample product (2) is of type A core wire 3, type B terminal fitting 1, type A crimping type, and the sample product (3) is type A core wire 3, type A terminal fitting 1, type B Crimp type, sample product (4) is type A core wire 3, type C terminal fitting 1, type A crimp type, sample product (5) is type A core wire 3, type A terminal fitting 1, type C Each of the crimping molds is used to crimp the core wire 3 with the crimping piece 2 of the terminal fitting 1.

  As shown in FIG. 6, the contact resistance R corresponding to the measured conductor compression ratio% (= crimp height) is the sample product (4), sample product (3), sample product (2), sample product ( 1) The sample product (5) increases in this order. Therefore, as the performance of the actually measured product, the sample product (4) is the best, and the sample product (3), the sample product (2), the sample product (1), and the sample product (5) become worse in this order.

  In contrast, the contact performance coefficient CC corresponding to the conductor compression ratio%, which is a simulation value, is also the sample product (4), sample product (3), sample product (2), sample product (1), sample product (5). ) In order. Therefore, similarly to the actual measurement product, the sample product (4) is the best from the contact performance coefficient CC that is a simulation value, and the sample product (3), the sample product (2), the sample product (1), and the sample product (5) It turns out that it gets worse in the order of). That is, it was found that the contact performance coefficient CC shown in the equation (1) is a value corresponding to the contact resistance R.

  According to the contact performance coefficient calculation device 6 described above, a plurality of sample products can be obtained by calculating the contact performance coefficient CC which is a simulation value without actually making a plurality of sample products and actually measuring the contact resistance R. The magnitude of the contact resistance R can be compared. For this reason, it can support that anyone can perform the connection design of the terminal metal fitting 1 and the core wire 3 easily and in a short time without being influenced by a designer's experience.

  According to the above-described embodiment, the finite element model conversion process for converting the caulking piece 2 and the core wire 3 input by the input process into the caulking piece model 2m and the core wire model 3m, respectively, is provided. It is not limited to. For example, the caulking piece model 2m corresponding to the types A, B, C... Of the terminal fitting 1 and the core wire model 3m corresponding to the types A, B, C. By selecting the type of 1 and the core wire 3, the caulking piece model 2m and the core wire model 3m may be input by input processing. In this case, it is not necessary to perform a finite element model conversion process.

  Further, the above-described embodiments are merely representative forms of the present invention, and the present invention is not limited to the embodiments. That is, various modifications can be made without departing from the scope of the present invention.

It is a block diagram which shows one Embodiment of the contact performance coefficient calculation apparatus which implemented the contact performance coefficient calculation method of this invention. It is a flowchart which shows the analysis simulation process procedure of CPU shown in FIG. It is explanatory drawing for demonstrating the deformation | transformation calculation process shown in FIG. (A) is explanatory drawing for demonstrating the deformation | transformation calculation process result shown in FIG. 2, (B) is an enlarged view of the X section of (A). It is a table | surface which shows the order of the core wire corresponding to sample goods (1)-(5), the type of a terminal metal fitting and a crimping | compression-bonding type | mold, contact resistance, and a contact performance coefficient. It is a graph which shows the contact resistance and contact performance coefficient of sample goods (1)-(5) corresponding to a conductor compressibility. (A) is a side view which shows the shape of the terminal metal fitting used for crimping connection, (B) is a figure which shows the shape of the anvil and crimper used for crimping work, (C) is a terminal metal fitting and a core wire. It is a figure which shows the state in the time of a crimping | compression-bonding operation | work, (D) is a figure which shows the state after crimping | bonding of a terminal metal fitting and a core wire. It is a graph which shows the relationship between crimp height at the time of crimping | bonding connection, sticking force, and contact resistance.

Explanation of symbols

1 Terminal fitting 2 Caulking piece 3 Core wire 4 Crimper (upper mold)
5 Anvil (bottom)
6 Contact performance coefficient calculation device 10 CPU (core wire model acquisition means, caulking piece model acquisition means, deformation calculation means, node extraction means, first distance calculation means, second distance calculation means, contact length calculation means, contact performance Coefficient calculation means)
L _{k + 1} distance (first distance)
L _k-1 distance (second distance)
N nodes N _S node N _Sk clause

Claims (2)

A contact performance coefficient calculation device for calculating a contact performance coefficient according to a contact resistance between a crimped piece provided on a terminal fitting and a core wire crimped on the crimped piece,
A core wire model acquisition means for acquiring a core wire model obtained by dividing the cross section of the core wire into a plurality of elements;
A caulking piece model obtaining means for obtaining a caulking piece model obtained by dividing a cross section of the caulking piece into a plurality of elements;
The core wire model after the core wire is caulked by the caulking piece sandwiched between the upper die and the lower die, the displacement of each node constituting the caulking piece model and the force acting on each node are calculated by the finite element method. Deformation calculation means;
A node extracting unit that extracts a node that contacts the caulking piece model from the nodes on the outline of the core model after the caulking from the displacement of each node calculated by the deformation calculating unit;
A node extracted by the node extracting unit and a first node between one of a pair of nodes adjacent to the node extracted by the node extracting unit among the nodes on the contour of the core model after the caulking First distance calculating means for obtaining a distance;
A second node between the node extracted by the node extracting unit and the other of the pair of nodes adjacent to the node extracted by the node extracting unit among the nodes on the contour of the core model after the caulking A second distance calculating means for obtaining a distance;
Contact length calculation means for obtaining 1/2 of the sum of the first distance and the second distance as the contact length of the node extracted by the node extraction means;
Finding the sum of the values obtained by multiplying the contact length determined for all the nodes extracted by the node extracting means and the force that the nodes extracted by the node extracting means act on the caulking piece model,
Contact performance coefficient calculating means for obtaining the reciprocal of the sum as the contact performance coefficient;
A contact performance coefficient calculation device comprising: A contact performance coefficient calculation method for calculating a contact performance coefficient according to the contact resistance between the crimped piece provided on the terminal fitting and the core wire crimped to the crimped piece using a computer that performs various processes according to the processing program. There,
The computer obtains a core wire model obtained by dividing the cross section of the core wire into a plurality of elements, and a caulking piece model obtained by dividing the cross section of the caulking piece into a plurality of elements;
The finite element is a displacement of each core constituting the core wire model and the caulking piece model after the core wire is caulked by the caulking piece with the computer sandwiched between the upper die and the lower die, and the force acting on each node. A step of calculating by law,
A step of extracting the section of the computer, contacts the crimping pieces model of sections on the contour of the core wire model after the caulking from the displacement of each node of the calculated,
The computer obtains a first distance between one of a pair of nodes adjacent to the extracted node among the extracted nodes and the nodes on the contour of the core model after the caulking. When,
The computer obtains a second distance between the extracted node and the other of the pair of nodes adjacent to the extracted node among the nodes on the outline of the core model after the caulking. When,
The computer determining 1/2 of the sum of the first distance and the second distance as a contact length of the extracted node;
The computer obtains a sum of values obtained by multiplying the contact length obtained for all the extracted nodes by a force acting on the caulking piece model by the extracted nodes, and calculates the reciprocal of the sum as the contact. A process to obtain as a performance factor;
The contact performance coefficient calculation method characterized by performing sequentially.

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