JP5123000B2 - Crimping performance coefficient calculation device and crimping performance coefficient calculation method - Google Patents

Description

  The present invention relates to a crimping coefficient calculation device and a crimping performance coefficient calculation method, and in particular, calculates a crimping performance coefficient according to contact resistance between a crimping piece provided on a terminal fitting and a core wire crimped to the crimping piece. The present invention relates to a crimping performance coefficient calculation device and a crimping 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 described above are sandwiched between the crimper 4 (upper mold) and the anvil 5 (lower mold), as shown in FIGS. 8B and 8C, 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. 8 (D).

  By the way, the relationship between the crimp height C / H after crimping (see FIG. 8D) 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 a non-linear characteristic 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 (“optimum crimp height shown in FIG. 9”). ") 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 crimping performance coefficient calculation device and a crimping performance coefficient calculation method for calculating a crimping performance coefficient according to 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 crimping performance coefficient calculation apparatus and a crimping performance coefficient calculation method for calculating the crimping performance coefficient according to the contact resistance by simulation without depending on the experience of the designer, The pressure-bonding performance coefficient R _CL shown in the formulas (1) and (2) was found to be a value corresponding to the contact resistance R, and the present invention was completed.

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

Note that ρ1 is the volume resistivity of the core wire, and ρ2 is the volume resistivity of the core wire. Further, as shown in FIG. 4 (B), L _{k + 1} is the caulking piece model 2m among the nodes on the contour of the core wire model 3m after crimping (after caulking) obtained by executing the finite element method. Of the nodes on the contour of the node N _SK that touches the node N _SK and the node N _{k + 1} adjacent to the node N _SK among the nodes on the contour of the core wire model 3m, L _k-1 is on the contour of the node 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 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 crimping performance coefficient calculation device for calculating a crimping performance coefficient according to contact resistance between a crimping piece provided on a terminal fitting and a core wire crimped on the crimping 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; The core wire model after the core wire is caulked with the caulking piece sandwiched between lower molds, deformation calculating means for calculating displacement of each node constituting the caulking piece model by a finite element method, and the deformation calculating means A node extracting means for extracting a node in contact with the caulking piece model among nodes on the contour of the core model after the caulking from the calculated displacement of each node; and the node extracting means A first distance between one of a pair of nodes adjacent to the node extracted by the node extraction unit among the extracted nodes and the nodes on the outline of the core model after the caulking is obtained. The other of the pair of nodes adjacent to the node extracted by the node extracting unit among the nodes extracted by the node extracting unit, the nodes extracted by the node extracting unit, and the nodes on the outline of the core model after the caulking The contact length of the node extracted by the node extracting unit is ½ of the sum of the second distance calculating unit for calculating the second distance between the first distance and the second distance. Contact length calculation means to be obtained as a sum, total calculation means to obtain the sum of the contact lengths obtained for all nodes extracted by the node extraction means, volume resistivity of the core wire and volume resistance of the caulking piece Sum obtained by the sum calculation means And crimping performance coefficient calculating means for calculating a value obtained by dividing eight times as the crimping merit resides in compression 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 provides a crimping performance coefficient corresponding to the contact resistance between the crimped piece provided on the terminal fitting and the core wire crimped on the crimped piece. A method for calculating a crimp 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. And the computer calculates the displacement of each core constituting the core wire model and the caulking piece model after the caulking piece is caulked between the upper die and the lower die by the finite element method. clause a step, the computer is in contact with the crimping piece model of 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 computer, the extracted section and one of a pair of nodes adjacent to the extracted section of the sections on the contour of the core wire model after the caulking, the first between a step of determining the distance, the computer, the extracted section and the other of the pair of nodes adjacent to the extracted section of the sections on the contour of the core wire model after the caulking, between a step of determining a second distance, a step wherein the computer, the first distance, and, for determining the second distance, the half of the sum as the contact length of the extracted section, the computer but a step of determining the contact length of the sum obtained for all clauses of the extracted, the computer, the sum of the volume resistivity of the crimping piece and the volume resistivity of the core by the total sum calculation step 8 times the total sum Resides value obtained by dividing the crimp performance coefficient calculating method characterized by sequentially performing the steps of calculating as the crimping performance factor.

  As described above, according to the first and second aspects of the invention, since the crimping 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, the crimping performance coefficient calculation device and the crimping performance coefficient calculation method of the present invention will be described with reference to the drawings. The crimping 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 crimped and connected, the terminal fitting 1-core wire 3 prior to the actual crimping connection. This is a device for calculating a crimping performance coefficient R _CL corresponding to the contact resistance R between the two.

  As shown in the figure, the crimping 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 crimping performance coefficient _RCL . The μCOM 9 is a ROM 11 which is a read-only memory storing a central processing unit (hereinafter referred to as CPU) 10 that controls the entire crimping performance coefficient calculation device 6 and performs various processes according to a processing program, and a processing program executed by the CPU 10. 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, operation | movement of the crimping | compression-bonding performance coefficient calculation apparatus 6 of the structure mentioned above is demonstrated 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. And the displacement of each node N which comprises the core wire model 3m and the caulking piece model 2m after releasing the anvil 5 and unloading the load applied to the caulking piece 2 and the core wire 3 is calculated. 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 displacement calculation process can calculate the displacement of 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 to obtain a later-described crimping performance coefficient R _CL corresponding to the contact resistance R between the crimping piece 2 and the core wire 3 from the displacement of each node N obtained by the deformation calculation process. . The contact resistance R is the sum of the concentrated resistance Rc and the film resistance Rf as shown in the following formula (3).
R = Rc + Rf (3)

なお、ρ１は芯線３の体積抵抗率であり、ρ２はかしめ片２の体積抵抗率である。

なお、ρｆは金属皮膜１３（図５）の体積抵抗率であり、ｄは金属皮膜１３の厚さ（一定と仮定）である。 As shown in FIG. 5, if the crimping piece 2 and the core wire 3 are in contact at a plurality of contact surfaces S ₁ , S ₂ ... Having radii a ₁ , a ₂ . Can be obtained by the following equations (4) and (5), respectively.

In addition, ρ1 is the volume resistivity of the core wire 3, and ρ2 is the volume resistivity of the caulking piece 2.

Here, ρf is the volume resistivity of the metal film 13 (FIG. 5), and d is the thickness of the metal film 13 (assuming constant).

  The thickness d of the metal film 13 is very thin. Therefore, the film resistance Rf is considered to be close to zero. Therefore, as is apparent from the equations (4) and (5), the contact resistance R increases as the sum of the volume resistivity ρ1 of the core wire 3 and the volume resistivity ρ2 of the caulking piece 2 increases. Further, the contact resistance R decreases as the contact area between the caulking piece 2 and the core wire 3 increases. 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, P _S in FIG. 5 (A) force acting on the node N _S on the core wire model 3m extracted in step S4, i.e., the crimping pieces model 2m 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. 5 (B), the caulking piece model 2m and the core wire model 3m are in contact with each other at a point (node), but 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 crimping performance coefficient calculation unit, 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. Crimping performance obtained by dividing the sum of the volume resistivity ρ1 of the core wire 3 and the volume resistivity ρ2 of the caulking piece 2 by 8 times the sum of the contact lengths L _k as the crimping performance coefficient R _CL After performing the coefficient calculation process (step S6), the calculated crimping performance coefficient R _CL is displayed on the display device 8 (step 7), and the analysis simulation process is terminated.

As is apparent from the equation (1), the crimping performance coefficient R _CL is a coefficient that increases as (ρ1 + ρ2) increases as in the case of the contact resistance R. The crimping performance coefficient R _CL is a coefficient that decreases as the contact length (area) L _k between the crimping piece 2 and the core wire 3 increases. That is, the present inventor assumed that the crimping performance coefficient R _CL shown in the above formula (1) would be a value corresponding to the contact resistance R.

Next, the inventor of the present invention uses the crimping performance coefficient R _CL calculated using the products of the present invention described above for the sample products (1) to (5) shown in FIG. 6, and the sample product (1) shown in FIG. The contact resistance R measured after actually producing prototype (5) and executing the thermal collision test was compared. 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. 7, the contact resistance R according 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 crimping performance coefficient R _CL 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 ( Increase in the order of 5). Therefore, similarly to the actual measurement product, the sample product (4) is the best from the crimping performance coefficient R _CL which is a simulation value, and the sample product (3), sample product (2), sample product (1), sample product ( It turns out that it gets worse in the order of 5). That is, it was found that the crimping performance coefficient R _CL shown in the equation (1) is a value corresponding to the contact resistance R.

According to the crimping performance coefficient calculation device 6 described above, a plurality of samples can be obtained by calculating the crimping performance coefficient R _CL 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 of the product 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 crimping performance coefficient calculation apparatus which implemented the crimping 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. It is explanatory drawing for demonstrating contact resistance. (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 terminal metal fitting and the crimping | compression-bonding type | mold, the order of contact resistance, and a crimping | crimping performance coefficient. It is a graph which shows the contact resistance and the crimping | compression-bonding performance coefficient of the 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 Crimping 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, crimping 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 crimping performance coefficient calculating device for calculating a crimping 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;
Deformation calculation means for calculating displacement of each node constituting the core wire model and the caulking piece model after caulking the core wire with the caulking piece sandwiched between an upper die and a lower die; and
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;
A sum total calculating means for calculating a sum of the contact lengths obtained for all the nodes extracted by the node extracting means;
A crimping performance coefficient calculating unit that calculates a value obtained by dividing the sum of the volume resistivity of the core wire and the volume resistivity of the caulking piece by 8 times the total obtained by the total calculating unit, as the crimping performance coefficient;
A crimping performance coefficient calculation device comprising: Using a computer that performs various processes according to a processing program, a crimping performance coefficient calculation method that calculates a crimping 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. 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;
Calculating the displacement of each node constituting the core wire model and the caulking piece model after the caulking piece is caulked with the caulking piece sandwiched between the upper die and the lower die by a finite element method;
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;
Calculating the sum of the contact lengths determined for all the extracted nodes by the computer ;
A step of calculating a value obtained by dividing the sum of the volume resistivity of the core wire and the volume resistivity of the caulking piece by 8 times the sum obtained by the sum calculation step as the crimping performance coefficient;
Are sequentially performed.

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