JP2023131499A - Terminal, electric wire with terminal, and method for manufacturing electric wire with terminal - Google Patents

Abstract

To reduce costs and prevent damage to a terminal when ultrasonically bonding an electric wire to a terminal.SOLUTION: A terminal includes a joint in which a conductor of an electric wire is joined, and a connection portion that is connected to the joint, has a minimum moment of inertia of area larger than the minimum moment of inertia of the joint, and is connected to a connection partner. Since the minimum moment of inertia of the connection portion is larger than the minimum moment of inertia of the joint, deformation of the connection portion is suppressed when ultrasonically welding a wire to the joint, thereby making it less prone to fatigue and preventing damage.SELECTED DRAWING: Figure 1

Description

The present invention relates to a terminal, an electric wire with a terminal, and a method of manufacturing the electric wire with a terminal.

As an invention for suppressing the influence of vibration on a terminal when a core wire of an electric wire is ultrasonically bonded to a metal terminal, there is an invention disclosed in Patent Document 1, for example. In this invention, first, one end side and the other end side in the width direction of a conductive plate material are bent, and the bent and overlapping portions are laser welded to form a terminal having a box portion having a rectangular cross section. Next, the core wire of the electric wire is bonded to the opposite side of the box portion in the length direction using an ultrasonic bonding device. In the invention disclosed in Patent Document 1, by forming a closed box part by laser welding, relative movement of the side wall part with respect to the bottom part of the box part is suppressed. By suppressing the relative movement of the side wall with respect to the bottom of the box, the spring housed inside the box is prevented from shaking significantly, and fatigue is prevented from concentrating on the spring and causing damage. There is.

JP 2021-150109 Publication

According to the technique disclosed in Patent Document 1, it is possible to suppress damage to the terminal during ultrasonic bonding. However, in the technique disclosed in Patent Document 1, it is necessary to perform laser welding of the box portion, which increases the number of man-hours and costs.

The present invention has been made in view of the above, and an object of the present invention is to provide a technique for reducing costs and preventing damage to a terminal when ultrasonically bonding an electric wire to a terminal.

In order to solve the above-mentioned problems and achieve the objects, a terminal according to the present invention has a joint part to which a conductor of an electric wire is joined, and a terminal that is connected to the joint part, and has a minimum moment of inertia of the joint part. A connecting portion having a moment of inertia larger than the area and being connected to a connecting partner.

In the terminal according to one aspect of the present invention, the connection portion may be thicker than the joint portion.

The terminal according to one aspect of the present invention may have a configuration in which the cross-sectional shape of the connecting portion is different from the cross-sectional shape of the joint portion.

In the terminal according to one aspect of the present invention, the connecting portion may have a concave cross-sectional shape, and the joining portion may have a rectangular cross-sectional shape.

In the terminal according to one aspect of the present invention, the connecting portion may have a hollow rectangular cross-sectional shape, and the connecting portion may have a rectangular cross-sectional shape.

The terminal according to one aspect of the present invention may have a configuration in which the number of sides forming the cross section of the connection part is greater than the number of sides forming the joint part.

The terminal according to one aspect of the present invention may have a configuration in which the minimum moment of inertia of the connecting portion is 6.7×10 ⁻¹³ m ⁴ or more.

The terminal according to one aspect of the present invention may have a configuration in which the thickness of the connecting portion is 1.3 mm or more and 7 mm or less.

In the terminal according to one aspect of the present invention, the connecting portion has a minimum moment of inertia of 1.0×10 ⁻¹¹ m ⁴ or more and less than 1.0×10 ⁻¹⁰ m ⁴ , and the length of the connecting portion is The length may be 1.2 mm or more and less than 30 mm.

In the terminal according to one aspect of the present invention, the connecting portion has a minimum moment of inertia of 1.0×10 ⁻¹⁰ m ⁴ or more and less than 1.0×10 ⁻⁹ m ⁴ , and the length of the connecting portion is It is good also as a structure which is 1.2 mm or more and less than 40 mm.

In the terminal according to one aspect of the present invention, the connecting portion has a minimum moment of inertia of 1.0×10 ⁻⁹ m ⁴ or more and less than 1.0×10 ⁻⁷ m ⁴ , and the length of the connecting portion is It is good also as a structure which is 1.2 mm or more and less than 50 mm.

An electric wire with a terminal according to the present invention includes a terminal having one of the above configurations and an electric wire, and a conductor of the electric wire is ultrasonically bonded to the joint portion of the terminal.

The method for manufacturing an electric wire with a terminal according to the present invention includes a joint part to which a conductor of the electric wire is joined, and a connecting part connected to the joint part, the minimum moment of inertia of the joint being larger than the minimum moment of inertia of the joint part, and a connecting partner. ultrasonically bonding the conductor to the bonding portion of a terminal having a connection portion connected to the terminal.

In the method for manufacturing an electric wire with a terminal according to one aspect of the present invention, a driving frequency of a horn of an ultrasonic bonding machine for ultrasonically bonding the conductor to the bonding portion is 20 kHz, and a frequency of vibration of the horn is 20 kHz. It may be within the range of -10% to 5% of the frequency.

According to the present invention, it is possible to reduce costs and prevent damage to the terminal when ultrasonically bonding the electric wire to the terminal.

FIG. 1 is a diagram showing the shape of a terminal according to the first embodiment. FIG. 2 is a graph showing the natural frequency of the terminal according to the first embodiment. FIG. 3 is a diagram showing the shape of a terminal according to the second embodiment. FIG. 4 is a graph showing the natural frequency of the terminal according to the second embodiment. FIG. 5 is a diagram showing the shape of a terminal according to the third embodiment. FIG. 6 is a graph showing the natural frequency of the terminal according to the third embodiment. FIG. 7 is a diagram showing the shape of a terminal according to the fourth embodiment. FIG. 8 is a graph showing the natural frequency of the terminal according to the fourth embodiment. FIG. 9 is a diagram showing the shape of a terminal according to the fifth embodiment. FIG. 10 is a graph showing the natural frequency of the terminal according to the fifth embodiment.

Embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Note that the present invention is not limited to the embodiments described below. Furthermore, in the description of the drawings, the same or corresponding elements are given the same reference numerals as appropriate. Furthermore, it should be noted that the drawings are schematic and the relationship between dimensions of each element may differ from reality. Drawings may also include portions that differ in dimensional relationships and ratios. Further, in the drawings, XYZ coordinate axes are shown as appropriate, and directions will be explained using these. In the space indicated by the XYZ coordinate axes, the direction in which the X component increases is called the +X direction, and the direction in which the X component decreases is called the -X direction. Similarly, the Y and Z components are defined as +Y direction, -Y direction, +Z direction, and -Z direction. Note that the Z-axis direction is a vertical direction, the +Z direction is vertically upward, and the -Z direction is also vertically downward.

[First embodiment]
FIG. 1(a) is a plan view of an electric wire 10 with a terminal according to a first embodiment of the present invention. The electric wire 10 with a terminal includes a terminal 1A and a covered electric wire 3. FIG. 1(b) is a plan view of the terminal 1A, and FIG. 1(c) is a front view of the terminal 1A. Further, FIG. 1(d) is a sectional view taken along line AA in FIG. 1(b), and FIG. 1(e) is a sectional view taken along line BB in FIG. 1(b).

The covered wire 3 includes a conductor 31 and a covering portion 32 that covers the conductor 31. The conductor 31 is, for example, a stranded wire in which a plurality of wires made of aluminum, aluminum alloy, copper, or copper alloy are twisted together. Note that the conductor 31 may be made by bundling a plurality of wires instead of twisting a plurality of wires together. The nominal cross-sectional area of the conductor 31 is 60 sq in this embodiment. The nominal cross-sectional area of the conductor 31 can be 16 sq or more, preferably 20 sq to 60 sq. Note that the nominal cross-sectional area of the conductor 31 may exceed 60 sq, and may be, for example, 90 sq or 100 sq.

The covering portion 32 can be selected from materials commonly used in this technical field, such as polyvinyl chloride (PVC) having insulating properties and polyolefin resins such as polyethylene and polypropylene. The covering portion 32 covers the outer periphery of the conductor 31 . At the tip of the covered wire 3, the covering portion 32 is removed to expose the conductor 31, and the exposed conductor 31 is joined to the terminal 1A.

The terminal 1A is a terminal electrically and mechanically connected to the conductor 31. The terminal 1A is formed by pressing a plate material made of copper or a copper alloy. In this embodiment, the thickness of the plate material is 2 mm, and the length in the Y-axis direction is 49 mm. Examples of the copper alloy forming the terminal 1A include brass, phosphor bronze, and Corson copper alloy, but it is preferable that the copper alloy has a higher melting point than the conductor 31.

The terminal 1A is roughly divided into a connecting portion 11a and a joining portion 12a. Note that the terminal 1A may have a structure in which the surface is subjected to tin plating treatment. When the terminal 1A is tin-plated, only the connecting portion 11a may be tin-plated, and the joint portion 12a may not be tin-plated.

The connecting portion 11a is a portion for connecting the terminal 1A to which the conductor 31 is joined to a terminal of another electric wire with a terminal, a terminal of a power source, etc., or a bus bar. The connecting portion 11a is formed by bending a plate material, and has a concave cross section along the XZ plane, as shown in FIG. 1(d). The connecting portion 11a has a width of 17 mm in the X-axis direction and a length of 31 mm in the Y-axis direction. Furthermore, the distance between the upper side and the lower side of the connecting portion 11a is 4 mm.

The bonding portion 12a is a portion where the conductor 31 is ultrasonically bonded. The joint portion 12a is plate-shaped and has a length in the Y-axis direction of 18 mm. Furthermore, the width of the joint portion 12a in the X-axis direction is 13 mm at the portion where the conductor 31 is joined.

When joining the conductor 31 to the terminal 1A, the joint portion 12a is placed on the anvil, and the conductor 31 is placed on the joint portion 12a. Next, a horn that vibrates ultrasonically in the Z-axis direction is brought into contact with the conductor 31 while applying pressure in the -Z direction, thereby joining the conductor 31 and the joint portion 12a. Note that although the driving frequency of the horn is, for example, 20 kHz, the vibration frequency of the horn is within the range of 18 kHz to 21 kHz due to variations in output. If the natural frequency of the terminal 1A matches the frequency variation range of the vibration of the horn, the terminal 1A will resonate and there is a risk that the terminal 1A will be damaged due to metal fatigue.

In this embodiment, the connecting portion 11a, which has a concave cross section as shown in FIG. 1(d), has a minimum area moment of inertia of 6.5×10 ⁻¹⁰ m ⁴ , and has a concave cross-section as shown in FIG. 1(e). As shown, the joint portion 12a, which has a rectangular cross section, has a minimum moment of inertia of 8.7×10 ⁻¹² m ⁴ . In calculating the minimum moment of inertia of area, the material of the terminal 1A is tough pitch copper, the density is 8890 kg/m ³ , and the Young's modulus is 1.18×10 ¹¹ N/m ² .

In this manner, the terminal 1A is configured such that the minimum moment of inertia of the connecting portion 11a is larger than the minimum moment of inertia of the joint portion 12a. By making the minimum moment of inertia of the connecting portion 11a larger than the minimum moment of inertia of the connecting portion 12a, the deformation of the connecting portion 11a is suppressed, making it less prone to fatigue and preventing damage.

FIG. 2 is a graph showing the relationship between the minimum moment of inertia of the connecting portion 11a and the natural frequency of the connecting portion 11a. The lower point plotted in FIG. 2 is the natural frequency of the first mode of the connection portion 11a, and the upper point is the natural frequency of the second mode of the connection portion 11a. Moreover, the range between the two broken lines shown in FIG. 2 is the frequency range of the vibration of the horn mentioned above in ultrasonic bonding. By adjusting the minimum moment of inertia of the connecting portion 11a according to its dimensions and shape, the natural frequency of the connecting portion 11a can be moved out of the range of 18 kHz to 21 kHz, which is the frequency range of horn vibration, as shown in FIG. Therefore, it is possible to prevent the connecting portion 11a from being damaged due to resonance with the vibration frequency of ultrasonic bonding.

[Second embodiment]
Next, a second embodiment of the present invention will be described. In the second embodiment, the configuration of the terminal to which the conductor 31 is bonded differs from the first embodiment. FIG. 3(a) is a plan view of the terminal 1B to which the conductor 31 is bonded, and FIG. 3(b) is a front view of the terminal 1B. Further, FIG. 3(c) is a sectional view taken along line CC in FIG. 3(a), and FIG. 3(d) is a sectional view taken along line DD in FIG. 3(a).

The terminal 1B is a terminal electrically and mechanically connected to the conductor 31. The terminal 1B is formed by pressing a plate material made of copper or a copper alloy. The terminal 1B is roughly divided into a connecting portion 11b, a joint portion 12b, and a barrel portion 13b. The terminal 1B has a length of 60 mm in the Y-axis direction.

The connecting portion 11b is a portion for connecting the terminal 1B to which the conductor 31 is bonded to a terminal of another electric wire with a terminal, a terminal of a power source, etc., or a bus bar. The connecting portion 11b is plate-shaped and has a length in the Y-axis direction of 25 mm and a width in the X-axis direction of 18.4 mm. Further, the thickness of the connecting portion 11b in the Z-axis direction is 2.3 mm.

The bonding portion 12b is a portion where the conductor 31 is ultrasonically bonded. The joint portion 12a is plate-shaped and rectangular when viewed from above, and the portion where the conductor 31 is ultrasonically bonded has a length of 9.6 mm in the Y-axis direction and a width of 9.6 mm in the X-axis direction. . Further, the joint portion 12b has a thickness of 1.2 mm in the Z-axis direction.

The barrel portion 13b has a barrel piece 14b and a barrel piece 15b. The barrel portion 13b is formed by forming the plate-shaped barrel piece 14b and the barrel piece 15b into a hollow tube shape by press working. The inner diameter of the tubular barrel portion 13b is a diameter into which the covered electric wire 3 can be inserted.

In this embodiment, the connecting portion 11b having a rectangular cross section as shown in FIG. 3(c) has a minimum moment of inertia of 1.9×10 ⁻¹¹ m ⁴ . Further, as shown in FIG. 3(d), the portion of the joint 12b to which the conductor 31 is connected has a rectangular cross section and a minimum moment of inertia of 1.38×10 ⁻¹² m ⁴ . In the calculation of the minimum moment of inertia, the material of the terminal 1B is tough pitch copper, the density is 8890 kg/m ³ , and the Young's modulus is 1.18×10 ¹¹ N/m ² .

In this manner, the terminal 1B is configured such that the minimum moment of inertia of the connecting portion 11b is greater than the minimum moment of inertia of the joint portion 12b. By making the minimum moment of inertia of the connecting portion 11b larger than the minimum moment of inertia of the connecting portion 12b, the deformation of the connecting portion 11b is suppressed, making it less susceptible to fatigue and preventing damage.

FIG. 4 is a graph showing the relationship between the minimum moment of inertia of the connecting portion 11b and the natural frequency of the connecting portion 11b. The points plotted in FIG. 4 are the natural frequencies of the first mode, second mode, third mode, and four o'clock mode in order from the bottom. Moreover, the range between the two broken lines shown in FIG. 4 is the frequency range of the vibration of the horn mentioned above in ultrasonic bonding. By adjusting the minimum cross-sectional moment of inertia of the connecting portion 11b depending on the dimensions and shape, the natural frequency of the connecting portion 11a can be moved out of the range of 18 kHz to 21 kHz, which is the frequency range of horn vibration, as shown in FIG. Therefore, it is possible to prevent the connecting portion 11b from being damaged due to resonance with the vibration frequency of ultrasonic bonding.

[Third embodiment]
Next, a third embodiment of the present invention will be described. In the third embodiment, the structure of the terminal to which the conductor 31 is bonded differs from the first embodiment. FIG. 5(a) is a plan view of the terminal 1C to which the conductor 31 is bonded, and FIG. 5(b) is a front view of the terminal 1C. Further, FIG. 5(c) is a sectional view taken along line EE in FIG. 5(a), and FIG. 5(d) is a sectional view taken along line FF in FIG. 5(a).

The terminal 1C is a terminal electrically and mechanically connected to the conductor 31. The terminal 1C is formed by pressing a plate material made of copper or a copper alloy. The terminal 1C is roughly divided into a connecting portion 11c, a joint portion 12c, and a barrel portion 13c. The terminal 1C has a length of 60 mm in the Y-axis direction.

The connecting portion 11c is a portion for connecting the terminal 1C to which the conductor 31 is joined to a terminal of another electric wire with a terminal, a terminal of a power source, etc., or a bus bar. The connecting portion 11c is formed by bending a plate material, and has a concave cross section along the XZ plane, as shown in FIG. 5(c). The connecting portion 11c has a width of 18.4 mm in the X-axis direction and a length of 35 mm in the Y-axis direction. Moreover, the thickness of each side of the concave shape of the connecting portion 11c is 2.3 mm, and the height from the bottom surface to the top surface is 10 mm.

The bonding portion 12c is a portion where the conductor 31 is ultrasonically bonded. The joint portion 12c is plate-shaped, has a length in the Y-axis direction of 18 mm, and a thickness in the Z-axis direction of 2.3 mm. Further, the width of the joint portion 12c in the X-axis direction is 18.4 mm.

The barrel portion 13c has a barrel piece 14c and a barrel piece 15c. The barrel portion 13c is formed by forming the plate-shaped barrel piece 14c and the barrel piece 15c into a hollow tube shape by press working. The inner diameter of the barrel portion 13c formed into a tubular shape is a diameter into which the covered electric wire 3 can be inserted.

In this embodiment, the connecting portion 11c, which has a concave cross section as shown in FIG. 5(c), has a minimum area moment of inertia of 1.3×10 ⁻⁹ m ⁴ , and as shown in FIG. 5(d). As shown, the joint portion 12c, which has a rectangular cross section, has a minimum moment of inertia of 1.9×10 ⁻¹¹ m ⁴ . In the calculation of the minimum moment of inertia, the material of the terminal 1C is tough pitch copper, the density is 8890 kg/m ³ , and the Young's modulus is 1.18×10 ¹¹ N/m ² .

In this manner, the terminal 1C is configured such that the minimum moment of inertia of the connecting portion 11c is larger than the minimum moment of inertia of the joint portion 12c. By making the minimum moment of inertia of the connecting portion 11c larger than the minimum moment of inertia of the connecting portion 12c, the deformation of the connecting portion 11c is suppressed, making it less prone to fatigue and preventing damage.

FIG. 6 is a graph showing the relationship between the minimum moment of inertia of the connecting portion 11c and the natural frequency of the connecting portion 11c. The lower point plotted in FIG. 6 is the natural frequency of the first mode, and the upper point is the natural frequency of the second mode. Moreover, the range between the two broken lines shown in FIG. 6 is the frequency range of the vibration of the horn mentioned above in ultrasonic bonding. As shown in FIG. 6, the natural frequency of the connecting portion 11c is outside the range of 18 kHz to 21 kHz, which is the frequency range of horn vibration, so the connecting portion 11c resonates with the vibration frequency of ultrasonic bonding and is damaged. can be suppressed.

[Fourth embodiment]
Next, a fourth embodiment of the present invention will be described. In the fourth embodiment, the configuration of the terminal to which the conductor 31 is bonded differs from the first embodiment. FIG. 7(a) is a plan view of the terminal 1D to which the conductor 31 is bonded, and FIG. 7(b) is a front view of the terminal 1D. Further, FIG. 7(c) is a sectional view taken along line GG in FIG. 7(a), and FIG. 7(d) is a sectional view taken along line HH in FIG. 7(a).

The terminal 1D is a terminal electrically and mechanically connected to the conductor 31. The terminal 1D is formed by pressing a plate material made of copper or a copper alloy. The terminal 1D is roughly divided into a connecting portion 11d, a joint portion 12d, and a barrel portion 13d. The terminal 1D has a length of 80 mm in the Y-axis direction.

The connecting portion 11d is a portion for connecting the terminal 1D to which the conductor 31 is joined to a terminal of another electric wire with a terminal, a terminal of a power source, etc., or a bus bar. The connecting portion 11d is formed by bending a plate material, and has a hollow rectangular cross section along the XZ plane, as shown in FIG. 7(c). The connecting portion 11d has a width of 18.4 mm in the X-axis direction and a length of 48 mm in the Y-axis direction. Furthermore, the connection portion 11d has a rectangular shape with a thickness of 2.3 mm on each side and a height of 18.4 mm from the bottom surface to the top surface.

The bonding portion 12d is a portion where the conductor 31 is ultrasonically bonded. The joint portion 12d is plate-shaped, has a width in the X-axis direction of 18.4 mm, and a thickness in the Z-axis direction of 2.3 mm.

The barrel portion 13d has a barrel piece 14d and a barrel piece 15d. The barrel portion 13d is formed by forming the plate-shaped barrel pieces 14d and 15d into a hollow tube shape by press working. The inner diameter of the barrel portion 13d formed into a tubular shape is a diameter into which the covered electric wire 3 can be inserted.

In this embodiment, the connecting portion 11d, which has a hollow rectangular cross section as shown in FIG. 7(c), has a minimum area moment of inertia of 6.6×10 ⁻⁹ m ⁴ , and as shown in FIG. 7(d). As shown in , the joint portion 12c having a rectangular cross section has a minimum moment of inertia of 1.9×10 ⁻¹¹ m ⁴ . In the calculation of the minimum moment of inertia, the material of the terminal 1D is tough pitch copper, the density is 8890 kg/m ³ , and the Young's modulus is 1.18×10 ¹¹ N/m ² .

In this way, the terminal 1D is configured such that the minimum moment of inertia of the connecting portion 11d is larger than the minimum moment of inertia of the connecting portion 12d. By making the minimum moment of inertia of the connecting portion 11d larger than the minimum moment of inertia of the connecting portion 12d, deformation of the connecting portion 11d is suppressed, making it less prone to fatigue and preventing damage.

FIG. 8 is a graph showing the relationship between the minimum moment of inertia of the connecting portion 11d and the natural frequency of the connecting portion 11d. The lower point plotted in FIG. 8 is the natural frequency of the first mode, and the upper point is the natural frequency of the second mode. Moreover, the range between the two broken lines shown in FIG. 8 is the frequency range of the vibration of the horn mentioned above in ultrasonic bonding. As shown in FIG. 8, the natural frequency of the connecting portion 11d is outside the range of 18 kHz to 21 kHz, which is the frequency range of horn vibration, so the connecting portion 11d resonates with the vibration frequency of ultrasonic bonding and is damaged. can be suppressed.

[Fifth embodiment]
Next, a fifth embodiment of the present invention will be described. In the fifth embodiment, the configuration of the terminal to which the conductor 31 is bonded differs from the first embodiment. FIG. 9(a) is a plan view of the terminal 1E to which the conductor 31 is bonded, and FIG. 9(b) is a front view of the terminal 1E. Further, FIG. 9(c) is a sectional view taken along line JJ in FIG. 9(a), and FIG. 9(d) is a sectional view taken along line KK in FIG. 9(a).

The terminal 1E is a terminal electrically and mechanically connected to the conductor 31. The terminal 1E is formed by pressing a plate material made of copper or a copper alloy. The terminal 1E is roughly divided into a connecting portion 11e, a joint portion 12e, and a barrel portion 13e. The terminal 1E has a length of 40 mm in the Y-axis direction.

The connecting portion 11e is a portion for connecting the terminal 1E to which the conductor 31 is bonded to a terminal of another electric wire with a terminal, a terminal of a power source, etc., or a bus bar. The connecting portion 11e is formed along the XZ plane. As shown in FIG. 9(c), a bolt hole with a diameter of 10 mm is formed in the connecting portion 11e and extends in the Y-axis direction. The connecting portion 11e has a width of 18.4 mm in the X-axis direction and a thickness of 2.3 mm in the Y-axis direction. Further, the height of the connecting portion 11e in the Z-axis direction is 40 mm.

The bonding portion 12e is a portion where the conductor 31 is ultrasonically bonded. The joint portion 12e is plate-shaped and has a thickness of 2.3 mm in the Z-axis direction. Further, the width of the joint portion 12e in the X-axis direction is 18.4 mm.

The barrel portion 13e has a barrel piece 14e and a barrel piece 15e. The barrel portion 13e is formed by forming plate-shaped barrel pieces 14e and 15e into a hollow tube shape by press working. The inner diameter of the barrel portion 13e formed into a tubular shape is a diameter into which the covered electric wire 3 can be inserted.

In this embodiment, as shown in FIG. 9(b), the connecting portion 11e formed by bending from the connecting portion 12e in the −Z direction has a minimum moment of inertia of 9.8×10 ⁻⁸ m ^{4 .} The joint portion 12e, which has a rectangular cross section as shown in FIG. 9(d), has a minimum moment of inertia of 1.9×10 ⁻¹¹ m ⁴ . In the calculation of the minimum moment of inertia, the material of the terminal 1C is tough pitch copper, the density is 8890 kg/m ³ , and the Young's modulus is 1.18×10 ¹¹ N/m ² .

In this manner, the terminal 1E is configured such that the minimum moment of inertia of the connecting portion 11e is larger than the minimum moment of inertia of the joint portion 12e. By making the minimum moment of inertia of the connecting portion 11e larger than the minimum moment of inertia of the connecting portion 12e, the deformation of the connecting portion 11e is suppressed, making it less prone to fatigue and preventing damage.

FIG. 10 is a graph showing the relationship between the minimum moment of inertia of the connecting portion 11e and the natural frequency of the connecting portion 11e. The points plotted in FIG. 10 are the natural frequencies of the first mode. Moreover, the range between the two broken lines shown in FIG. 10 is the frequency range of the vibration of the horn mentioned above in ultrasonic bonding. As shown in FIG. 10, the natural frequency of the connecting portion 11e is outside the frequency range of 18 kHz to 21 kHz, which is the frequency range of horn vibration, so the connecting portion 11e resonates with the vibration frequency of ultrasonic bonding and is damaged. can be suppressed.

[Preferred configuration of connection part]
Next, the relationship between the length of the above-mentioned connection portion and the minimum moment of inertia of area will be explained. The inventor studied the strength of an electric wire with a terminal by changing the length in the Y-axis direction and the minimum moment of inertia of the connecting portion of the terminal according to the above-described embodiment. Table 1 shows the results of a tensile test of electric wires with terminals by changing the length in the Y-axis direction and the minimum moment of inertia of the terminal connection part. In addition, in the test, when creating an electric wire with a terminal, the cross-sectional area of the conductor to be joined to the terminal was set to 60 sq. Further, in the ultrasonic bonding of the conductor 31 to the terminal, the bonding conditions were energy in the range of 8000 J to 12000 J, pressurization pressure in the range of 2 kN to 4 kN, and amplitude of 80% to 100%. Regarding the evaluation of the tensile test, if the tensile strength is 3N or more, "○" indicates good strength, if the tensile strength is less than 3N, "△" indicates insufficient strength, and if the terminal has cracks or deformation during the tensile test. Rated "x".

As shown in Table 1, the minimum moment of inertia of the connecting part of the terminal is 1.0 × 10 ^-11 m ⁴ or more when the length of the connecting part in the Y-axis direction is less than 30 mm. Preferably, when the length of the connecting portion in the Y-axis direction is 30 mm or more and less than 40 mm, it is preferably 1.0×10 ⁻¹⁰ m ⁴ or more. Further, the minimum moment of inertia of the connecting portion of the terminal is preferably 1.0×10 ⁻⁹ m ⁴ or more when the length of the connecting portion in the Y-axis direction is 40 mm or more and less than 50 mm.

In addition, increasing the minimum moment of inertia of the joint will improve the tensile strength, but if the minimum moment of inertia of the joint is 1.0 × 10 ^-7 m ⁴ or more, the weight of the joint and Due to the increased volume, the minimum moment of inertia of the connection is preferably less than 1.0×10 ⁻⁷ m ⁴ . In addition, if the minimum moment of inertia of the connection part is less than 6.7 x 10 ^{-13 m4} , the thickness and width in the X-axis direction will become narrow, and if the covered wire 3 is a high-voltage wire, , the area required for electrical connection with the connection destination is insufficient, so it is preferably 6.7×10 ⁻¹³ m ⁴ or more.

Further, the thickness of the connecting portion of the terminal is preferably 1.3 mm or more and 7 mm or less, and from the viewpoint of weight reduction and cost, it is preferably 1.3 mm or more and 3.5 mm or less.

[Modified example]
Although the embodiments of the present invention have been described above, the present invention is not limited to the embodiments described above, and can be implemented in various other forms. For example, the above-described embodiment may be modified as follows to implement the present invention. Note that the above-described embodiment and the following modified examples may be combined. The present invention also includes configurations in which the constituent elements of each embodiment and each modification example described above are combined as appropriate. Moreover, further effects and modifications can be easily derived by those skilled in the art. Therefore, the broader aspects of the present invention are not limited to the above-described embodiments and modifications, and various changes are possible.

In the third embodiment described above, the cross-sectional shape of the connecting portion is concave, and in the fourth embodiment, the cross-sectional shape of the connecting portion is a hollow rectangle. However, when forming the connecting portion by bending the plate material, the connecting portion The cross-sectional shape is not limited to a concave shape or a hollow rectangle. In the case where the connecting portion of the terminal is formed by bending the plate material, the number of sides forming the cross section of the connecting portion may be greater than the number of sides forming the cross section of the joint portion.

The driving frequency of the horn of the ultrasonic bonding machine for bonding the conductor 31 to the joint portion is not limited to 20 kHz, and may be any other frequency. The driving frequency of the horn of the ultrasonic bonding machine for bonding the conductor 31 to the bonding portion may be, for example, within the range of 20 kHz to 120 kHz.

1A, 1B, 1C, 1D, 1E Terminal 3 Covered wire 10 Electric wire with terminal 11a, 11b, 11c, 11d, 11e Connection portion 12a, 12b, 12c, 12d, 12e Joint portion 13b, 13c, 13d, 13e Barrel portion 14b, 14c, 14d, 14e Barrel piece 15b, 15c, 15d, 15e Barrel piece 31 Conductor 32 Covering part

Claims (14)

a joint where a conductor of the electric wire is joined;
a connecting portion that is connected to the joint, has a minimum moment of inertia of area larger than a minimum moment of inertia of the joint, and is connected to a connection partner;
A terminal with a The terminal according to claim 1, wherein the thickness of the connection portion is thicker than the thickness of the joint portion. The terminal according to claim 1 or 2, wherein a cross-sectional shape of the connecting portion is different from a cross-sectional shape of the joint portion. The terminal according to claim 3, wherein the connecting portion has a concave cross-sectional shape, and the joining portion has a rectangular cross-sectional shape. The terminal according to claim 3, wherein the connecting portion has a hollow rectangular cross-section, and the joint portion has a rectangular cross-section. The terminal according to claim 3, wherein the number of sides forming the cross section of the connection part is greater than the number of sides forming the joint part. The terminal according to any one of claims 1 to 6, wherein the connecting portion has a minimum moment of inertia of 6.7×10 ⁻¹³ m ⁴ or more. The terminal according to any one of claims 1 to 7, wherein the thickness of the connecting portion is 1.3 mm or more and 7 mm or less. The minimum moment of inertia of the connecting portion is 1.0×10 ⁻¹¹ m ⁴ or more and less than 1.0×10 ⁻¹⁰ m ⁴ , and the length of the connecting portion is 1.2 mm or more and less than 30 mm. 9. A terminal according to any one of claims 1 to 8. The minimum moment of inertia of the connecting portion is 1.0×10 ⁻¹⁰ m ⁴ or more and less than 1.0×10 ⁻⁹ m ⁴ , and the length of the connecting portion is 1.2 mm or more and less than 40 mm. 9. A terminal according to any one of claims 1 to 8. The minimum moment of inertia of the connecting portion is 1.0×10 ⁻⁹ m ⁴ or more and less than 1.0×10 ⁻⁷ m ⁴ , and the length of the connecting portion is 1.2 mm or more and less than 50 mm. 9. A terminal according to any one of claims 1 to 8. The terminal according to any one of claims 1 to 11;
having an electric wire;
the conductor of the electric wire is ultrasonically bonded to the joint portion of the terminal;
Electric wire with terminal. The joining of a terminal having a joining part to which a conductor of an electric wire is joined, and a connecting part connected to the joining part, having a minimum moment of inertia of area larger than the minimum moment of inertia of the joining part, and connected to a connection partner. A method for manufacturing an electric wire with a terminal, comprising the step of ultrasonically bonding the conductor to the portion. 13. A driving frequency of a horn of an ultrasonic bonding machine for ultrasonically bonding the conductor to the bonding portion is 20 kHz, and a vibration frequency of the horn is within a range of -10% to 5% of the driving frequency. A method for manufacturing an electric wire with a terminal described in .

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