JP2008311219A - Bonding structure of electric connection terminal and electric motor provided with electric connection terminal - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a bonding structure of an electric connection terminal in which a positioning for welding is easy and an welding fixation can be surely made even by a low output welding machine. <P>SOLUTION: An external connection terminal 31 formed in a flat plate shape is jointed by welding with a bus bar terminal 36. The both of the terminals 31, 36 have a bifurcated top end and each of the top end portions has a cut-out groove 41. Two welding joint portions 42a, 42b are formed by the cut-out grooves 41 on the top end portions of both of the terminals 31, 36. After a positioning of both of the cut-out grooves 41 is made respectively and while they are positioned each other, the external connecting terminal 31 and the bus bar terminal 36 are welded at the welding joint portions 42a, 42b and electrically connected. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an electrical connection terminal used for an electric motor or the like, and more particularly, to a structure of a welded portion of a connection terminal joined by welding.

  Conventionally, various methods such as screwing, soldering, and welding have been used as connection forms between electrical connection terminals. For example, in an electric motor described in Patent Document 1 (hereinafter abbreviated as “motor”), a power supply terminal connected to an external power supply and a motor power supply terminal are fixed by welding. FIG. 7 is an explanatory view showing an example of a terminal connection structure employed in such a motor. In the terminal connection part 51 of FIG. 7, the flat plate-like external connection terminals 52a to 52c and the flat plate-like motor power supply terminals 53a to 53c are arranged facing each other, and both terminals are joined by welding.

The external connection terminals 52a to 52c are L-shaped with one end side rising upward, and a lead wire 54 is connected to the other end side. The motor power supply terminals 53a to 53c extend so as to face one end side of the external connection terminals 52a to 52c, and are electrically connected to the motor coil. When welding both terminals, the motor power supply terminals 53a to 53c and the external connection terminals 52a to 52c are brought into contact with each other as shown in FIG. Arc welding (tig welding) is generally used for welding between terminals, and a substantially spherical weld is formed at the tip of both terminals. Thereby, both terminals are fixed in a state where they are electrically connected.
JP 2004-304945 A

  However, in the case of such a terminal connection structure, when there are a plurality of lead wires as shown in FIG. 7, there is a problem that it is necessary to perform alignment for each line and it is difficult to perform the welding operation. In addition, as described above, arc welding is used for terminal welding. However, if the area of the terminal (welded part) is increased, the welded part may not be melted. It needs to be thick. When the output of the welding machine is increased, the apparatus cost and running cost increase, which causes a cost increase. In addition, when a thick electrode is used, it is necessary to provide a space for allowing the electrode to escape during welding work. For example, when the terminal to be fixed by welding is a motor terminal as described above, if a space for escaping the electrode is provided in the motor, the physique of the motor may be increased accordingly, and the motor can be reduced in size and cost. There was also a problem that it was against the trend of conversion.

  It is an object of the present invention to provide an electrical connection terminal joining structure that is easy to align during welding and that can be securely fixed even by a low-power welding machine.

  The joint structure of the electrical connection terminals of the present invention is a joint structure of electrical connection terminals in which the electrical connection terminals formed in a flat plate shape are joined together by welding and the connection terminals are electrically connected. Then, a notch groove is provided at the tip of the connection terminal, and the connection terminals are welded together at a plurality of weld joints separated by the notch groove.

  In the present invention, since the connection terminals are welded at the welded joints separated by the notch grooves, the welded structure has a plurality of welded parts. For this reason, the area of each welding part becomes small, it becomes possible to use a welding machine with small output, and it becomes unnecessary to use a thick electrode. In addition, since there are a plurality of welded portions, even if one welded portion is damaged, electrical connection is secured by the other welded portion, and the reliability of electrical connection is improved.

  In the joint structure of the electrical connection terminals, the connection terminals may be welded in a state of being positioned with each other by aligning the notch grooves, thereby facilitating the positioning and positioning accuracy of the weld joint. Will also improve.

  In the joint structure of the electrical connection terminals, the width of the notch groove and the plate thickness of the connection terminal may be set to different dimensions. In this case, the width of the notch groove may be set larger or smaller than the plate thickness of the connection terminal. This makes it difficult for the terminals to be entangled during the plating process or when parts are fed during insert molding, thereby facilitating process management and improving yield by reducing plating defects. In particular, when the width of the notch groove is set smaller than the plate thickness of the connection terminal, it is possible to more reliably prevent the terminals from being entangled.

  An electric motor having an electrical connection terminal of the present invention is disposed on one end side of a stator core, and includes a bus bar unit including a bus bar terminal electrically connected to a stator coil, and is disposed adjacent to the bus bar unit in the axial direction. A bracket holder unit having an external connection terminal electrically connected to an external power source, wherein the bus bar terminal and the external connection terminal are joined by welding, the bus bar terminal and the external It has a notch groove formed at the tip of the connection terminal, and a plurality of weld joints separately formed at the tip of the bus bar terminal and the external connection terminal by the notch groove.

  In the present invention, a notch groove is formed at the front end portion of the bus bar terminal and the external connection terminal, and a plurality of weld joints are separately formed at the front end portion of the bus bar terminal and the external connection terminal by the notch groove. The connection terminals are welded at the separated welded joints, and a plurality of welds are provided. For this reason, the area of each welding part becomes small, it becomes possible to use a welding machine with small output, and it becomes unnecessary to use a thick electrode. In addition, since there are a plurality of welds, even if one weld is damaged, electrical connection is ensured by the other weld and the reliability of the electrical joint is improved.

  In the electric motor, by aligning the notch grooves, the bus bar terminal and the external connection terminal may be welded in a state of being positioned with respect to each other. Will also improve.

  In the electric motor, the width of the notch groove and the thickness of the connection terminal may be set to different dimensions. In this case, the width of the notch groove may be set larger or smaller than the plate thickness of the connection terminal. This makes it difficult for the terminals to be entangled during the plating process or when parts are fed during insert molding, thereby facilitating process management and improving yield by reducing plating defects. In particular, when the width of the notch groove is set smaller than the plate thickness of the connection terminal, it is possible to more reliably prevent the terminals from being entangled.

  According to the electrical connection terminal joining structure of the present invention, the electrical connection terminal joining structure formed by welding the electrical connection terminals formed in a flat plate shape with a notch groove at the tip of the connection terminal Since the connection terminals are welded to each other at a plurality of welded joints separated by the cutout grooves, a plurality of welds are provided, and the area of each weld is reduced. For this reason, it becomes possible to use a welding machine with a small output, and welding work itself becomes easy. Therefore, it is possible to reduce the apparatus cost and the like, reduce the number of welding work steps, and reduce the product cost. In addition, since it is not necessary to use thick electrodes for welding, the degree of freedom of layout inside the motor is increased, and the motor itself is easily reduced in size. Furthermore, since there are a plurality of welds, even if one weld is damaged, electrical connection is ensured by the other weld and the reliability of the electrical joint can be improved. .

  According to the electric motor of the present invention, the electric motor includes a bus bar unit including a bus bar terminal and a bracket holder unit including an external connection terminal, and the bus bar terminal and the external connection terminal are joined by welding. A notch groove is formed at the distal end portion of the external connection terminal, and a plurality of weld joints are separately formed at the distal end portion of the bus bar terminal and the external connection terminal by the notch groove. By welding, both terminals can be welded at a plurality of locations. For this reason, the area of each welding part becomes small, it becomes possible to use a welding machine with small output, and welding work itself becomes easy. Therefore, it is possible to reduce the apparatus cost and the like, reduce the number of welding work steps, and reduce the product cost. In addition, since it is not necessary to use thick electrodes for welding, the degree of freedom of layout inside the motor is increased, and the motor itself is easily reduced in size. Furthermore, since there are a plurality of welded portions, even if one welded portion is damaged, electrical connection is ensured by the other welded portion, and the reliability of the electrical joint portion can be improved. .

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a cross-sectional view showing a configuration of a motor employing a joining structure according to the present invention. The motor 1 in FIG. 1 has a brushless structure and is used as a drive source for an electric power steering apparatus. As shown in FIG. 1, the motor 1 has an inner rotor type configuration in which a stator 2 is arranged on the outside and a rotor 3 is arranged on the inside.

  The stator 2 includes a bottomed cylindrical case 4, a stator core 5, a stator coil 6 (hereinafter abbreviated as a coil 6) wound around the stator core 5, and a bus bar unit 7 attached to the stator core 5. . The case 4 is formed in a bottomed cylindrical shape with iron or the like, and an aluminum die cast bracket 8 is attached to an opening of the case 4 with a fixing screw (not shown). A synthetic resin insulator 11 is attached around the stator core 5.

  A coil 6 is wound around the outside of the insulator 11, and an end portion 6 a of the coil 6 is drawn out in the radial direction on one end side of the stator core 5. A bus bar unit 7 in which a copper bus bar is insert-molded in a synthetic resin main body is attached to one end side of the stator core 5. Around the bus bar unit 7, a plurality of power feeding terminals 12 project in the radial direction, and when the bus bar unit 7 is attached, the coil end 6 a is welded to the power feeding terminal 12. In the bus bar unit 7, the number of bus bars corresponding to the number of phases of the motor 1 (here, three for the U phase, V phase, and W phase) is provided, and each coil 6 is a power supply terminal corresponding to that phase. 12 is electrically connected. After the bus bar unit 7 is attached, the stator core 5 is press-fitted into the case 4 and bonded and fixed to the inner peripheral surface of the case.

  A rotor 3 is inserted inside the stator 2. The rotor 3 has a rotor shaft 13, and the rotor shaft 13 is rotatably supported by bearings 14a and 14b. The bearing 14 a is fixed to the center of the bottom of the case 4, and the bearing 14 b is fixed to the center of the bracket 8. A cylindrical rotor core 15 is fixed to the rotor shaft 13, and a segment type magnet 16 is attached to the outer periphery thereof. A magnet holder 17 made of synthetic resin is inserted on the rotor shaft 13, and the magnet 16 is disposed on the outer periphery of the rotor core 15 so as to be held by the magnet holder 17. A bottomed cylindrical magnet cover 18 is attached to the outside of the magnet 16.

  A resolver (angle sensor) 21 that detects the rotational position of the rotor 3 is accommodated in the bracket 8. The resolver 21 includes a resolver stator 22 fixed to the bracket 8 side and a resolver rotor 23 fixed to the rotor 3 side. A coil 24 is wound around the resolver stator 22, and an excitation coil and a detection coil are provided. The resolver stator 22 is press-fitted into a metal resolver holder 25 and fixed to a bracket holder unit 26 disposed in the bracket 8 in that state. The bracket holder unit 26 is made of synthetic resin, and a metal female screw portion 27 is insert-molded. A mounting screw 28 is screwed into the female screw portion 27 from the outside of the bracket 8, whereby the resolver holder 25 is fixed to the inside of the bracket 8.

  A resolver rotor 23 fixed to the left end portion of the magnet holder 17 is disposed inside the resolver stator 22. The resolver rotor 23 has a structure in which metal plates are laminated, and has convex portions in three directions. When the rotor shaft 13 rotates, the resolver rotor 23 also rotates in the resolver stator 22. A high frequency signal is given to the exciting coil of the resolver stator 22, and the phase of the signal output from the detection coil changes due to the proximity of the convex portion. The rotational position of the rotor 3 is detected by comparing the detection signal with the reference signal. Then, based on the rotational position of the rotor 3, the current to the coil 6 is appropriately switched, and the rotor 3 is rotationally driven.

  The bracket 8 is provided with a power supply external connection terminal 31 electrically connected to an external power source (not shown). The external connection terminal 31 is provided for each phase of U, V, and W (31 U, 31 V, and 31 W), and is provided on the terminal unit 32 that is fixed to the outer peripheral portion of the bracket 8. FIG. 2 is a plan view showing the configuration of the terminal unit 32 that employs the joining structure according to the first embodiment of the present invention, and FIG. 3 is a cross-sectional view taken along the line AA of FIG.

  As shown in FIG. 2, the terminal unit 32 includes a metal terminal cover 33 and a terminal holder 34 accommodated in the terminal cover 33. The terminal holder 34 is formed of synthetic resin, and the external connection terminal 31 is insert-molded inside. A lead wire (harness) 35 connected to an external power source is inserted into the terminal holder 34, and the lead wire 35 is fixed to the external connection terminal 31 by welding. When such a terminal unit 32 is fixed to the outer periphery of the bracket 8, the external connection terminal 31 is arranged so as to extend radially from the side of the bracket 8 toward the inside as shown in FIG. 1.

  Each external connection terminal 31 is welded and fixed to a bus bar terminal (electrical connection terminal) 36 (36U, 36V, 36W) provided in the bus bar unit 7 inside the motor. The bus bar terminal 36 protrudes from the bus bar unit 7 in the axial direction. When the bracket 8 is assembled to the case 4, the bus bar terminal 36 and the external connection terminal 31 face each other in parallel as shown in FIG. In the motor 1, after the bracket 8 is attached to the case 4, the bus bar terminal 36 and the external connection terminal 31 are fixed by welding. A working hole 37 is formed in the bracket 8, and a bracket cap 38 is attached to the working hole 37 after the welding process.

  Here, in the motor 1, as shown in FIG. 4, a notch groove 41 is formed in the external connection terminal 31 and the bus bar terminal 36, and the terminal tip portion has a bifurcated shape. FIG. 5 is an explanatory view showing the tip shapes of the external connection terminal 31 and the bus bar terminal 36. As shown in FIG. 5, a cutout groove 41 having a width a and a length c is formed at the center of the tip of both terminals 31, 36, and the welded tip of the terminal is welded at two locations by the cutout groove 41. Joint portions 42a and 42b are formed. In this case, the width a is about 1/6 (a≈b / 6) with respect to the terminal width b, and the length c is about 1/2 (c≈b / 2) with respect to the terminal width b. . For example, when the terminals 31 and 36 having a width b = 8 mm (plate thickness: 1.2 mm) are used, the notch groove 41 is formed to have a width a = 1.3 mm and a length c = 4 mm.

  The external connection terminal 31 and the bus bar terminal 36 are welded and electrically connected by weld joints 42a and 42b separated by the notch groove 41, respectively. As described above, when the distal end portions of the external connection terminal 31 and the bus bar terminal 36 are bifurcated, the welded portions are dispersed in two locations, and the area of each welded portion is reduced. For this reason, it becomes possible to use a welding machine with a small output, and welding work itself becomes easy. Accordingly, it is possible to reduce the apparatus cost and running cost related to the welding machine, reduce the number of welding work steps, and reduce the product cost. Moreover, since it is not necessary to use a thick electrode for welding, the degree of freedom in the layout inside the motor is increased, and the motor itself is easily reduced in size.

  Furthermore, since there are two welded portions with the notch groove 41 in between, even if one welded portion is damaged, the other remains and functions as an electrical joint. That is, in the motor 1, a backup function is added to the electrical junction. For this reason, the reliability of the electrical joint is improved, and the reliability of the motor can be improved.

  In addition, in the motor 1, the terminals 31 and 36 can be easily positioned by aligning the notch grooves 41 with each other. That is, since the cutout groove 41 serving as a positioning index exists in both the terminals 31 and 36, both can be easily positioned and a welding process with high positional accuracy can be performed. In particular, since each external connection terminal 31 is molded integrally with the terminal holder 34, each external connection terminal 31 is accurately arranged at a predetermined position with respect to the terminal unit 32. For this reason, in the motor 1, when the terminal unit 32 is fixed to the bracket 8, the external connection terminals 31 are accurately arranged in the bracket 8, and the positioning of the terminals 31 and 36 is further facilitated.

  Next, a description will be given of a terminal unit that employs a joint structure that is Embodiment 2 of the present invention. FIG. 6 is an explanatory diagram illustrating a configuration of the external connection terminal 45 used in the terminal unit according to the second embodiment. The configuration other than the external connection terminals is the same as that of the motor 1 of the first embodiment. Moreover, in Example 2, the same code | symbol is attached | subjected about the member similar to Example 1, and the description is abbreviate | omitted.

  Here, the above-described external connection terminal 31 is a component in which tin (tin) plating is applied to a copper-based metal terminal because it is welded to the lead wire 35. When tin plating is performed on the external connection terminal 31, the terminal is a component whose product appearance is not a problem, and therefore, rotary plating using a barrel is generally performed in consideration of cost. However, as described above, since the external connection terminal 31 has the notch groove 41 formed at the tip thereof, the width a of the notch groove 41 is set to be equal to or slightly larger than the plate thickness t of the terminal. In this case, there is a problem that the terminals are entangled during the plating process or when the parts are fed at the time of insert molding, and the handling is difficult. In addition, there is a problem that a part which is tangled during the plating process and plated as it is becomes a defective product, which is disadvantageous in terms of product cost.

  Therefore, in the external connection terminal 45 of this embodiment, the width a is set to a dimension that prevents other terminals from being entangled in the notch groove 41 in order to prevent the entanglement between the terminals as described above. That is, if the dimension of the notch groove 41 is not particularly taken into consideration and a≈t, the terminals are easily entangled with each other. Therefore, in the external connection terminal 45, the width a of the notch groove 41 is substantially the same as the terminal plate thickness t. The width a is larger than the plate thickness t (a> t: FIG. 6A), or the width a is smaller than the plate thickness t (a <t: FIG. 6A). Has been.

  In this case, if a> t as shown in FIG. 6A, another terminal may enter the notch groove 41. However, by taking a large difference between them (preferably, a ≧ 1.2t ), Even if another terminal enters the groove, both are easily separated. Further, as shown in FIG. 6B, if a <t, there is no possibility that other terminals enter the notch groove 41 in the first place. Therefore, by setting the width a of the notch groove 41 to such a dimension, it is possible to prevent the terminals from being entangled with each other during the plating process, etc. Yield is improved and product costs are reduced. In particular, the setting shown in FIG. 6B can more reliably prevent the terminals from being entangled, is preferable in terms of dimension setting, and is also preferable in terms of process management.

  It goes without saying that the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the scope of the invention.

  For example, in the above-described embodiment, an example in which one notch groove 41 is provided at the distal ends of the external connection terminal 31 and the bus bar terminal 36 is shown, but the notch groove 41 may be increased according to the terminal width. For example, when the terminal width is about 12 mm, two notch grooves 41 can be provided to form a trifurcated shape. Needless to say, when the welding location is divided into a plurality of locations, including the previous embodiment, the weld joint strength between the terminals 31 and 36 should be more than the required value. Further, the above-described numerical values relating to the terminal width b and the like are merely examples, and the present invention is not limited to the above-described numerical values.

  Furthermore, in the above-described embodiment, an example in which the joint structure according to the present invention is applied to an electric motor has been shown. However, the present invention can be widely applied to a joint structure between electrical connection terminals.

It is sectional drawing which shows the structure of the motor which employ | adopted the joining structure by this invention. It is a top view which shows the structure of the terminal unit which employ | adopted the junction structure which is Example 1 of this invention. It is sectional drawing along the AA line of FIG. It is explanatory drawing which shows the state which the bus-bar terminal and the external connection terminal faced in parallel. It is explanatory drawing which shows the front-end | tip part shape of an external connection terminal and a bus-bar terminal. It is explanatory drawing which shows the structure of the external connection terminal used for the terminal unit of Example 2 of this invention. It is explanatory drawing which shows the structure of the conventional motor terminal connection part, (a) is the top view, (b) is a side view for 1 terminal. It is explanatory drawing which shows the state at the time of welding the motor electric power feeding terminal and external connection terminal in the conventional motor.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Electric motor 2 Stator 3 Rotor 4 Case 5 Stator core 6 Coil 6a Coil end part 7 Bus bar unit 8 Bracket 11 Insulator 12 Feed terminal 13 Rotor shaft 14a Bearing 14b Bearing 15 Rotor core 16 Magnet 17 Magnet holder 18 Magnet cover 21 Resolver 22 Resolver stator 23 Resolver rotor 24 Coil 25 Resolver holder 26 Bracket holder unit 27 Female thread portion 28 Mounting screw 31 External connection terminal (electrical connection terminal)
32 Terminal unit 33 Terminal cover 34 Terminal holder 35 Lead wire 36 Bus bar terminal (electrical connection terminal)
37 Working hole 38 Bracket cap 41 Notch grooves 42a and 42b Welded joint 45 External connection terminal 51 Terminal connection parts 52a to 52c External connection terminals 53a to 53c Motor power supply terminal 54 Lead wire a Notch groove width b Terminal width c Notch groove length

Claims (10)

Joining the electrical connection terminals formed in a flat plate shape by welding, a connection structure of electrical connection terminals to electrically connect between the connection terminals,
A connection structure for electrical connection terminals, characterized in that a notch groove is provided at the tip of the connection terminal, and the connection terminals are welded together at a plurality of weld joints separated by the notch groove.   2. The electrical connection terminal joining structure according to claim 1, wherein the connection terminals are welded in a state of being positioned to each other by aligning the notch grooves. 3. Joining structure.   3. The connection structure for electrical connection terminals according to claim 1, wherein a width of the notch groove and a plate thickness of the connection terminal are different.   4. The electrical connection terminal joining structure according to claim 3, wherein a width of the notch groove is larger than a plate thickness of the connection terminal.   4. The electrical connection terminal joining structure according to claim 3, wherein a width of the notch groove is smaller than a plate thickness of the connection terminal. A bus bar unit having a bus bar terminal attached to one end side of the stator core and electrically connected to the stator coil, and an external connection terminal arranged adjacent to the bus bar unit in the axial direction and electrically connected to an external power source A bracket holder unit comprising: an electric motor in which the bus bar terminal and the external connection terminal are joined by welding,
A notch groove formed in a front end portion of the bus bar terminal and the external connection terminal;
An electric motor having an electrical connection terminal, wherein the cutout groove has a plurality of weld joints separately formed at the front end of the bus bar terminal and the external connection terminal.   7. The electric motor according to claim 6, wherein the bus bar terminal and the external connection terminal are welded while being positioned with respect to each other by aligning the notch grooves. Electric motor.   9. The electric motor according to claim 7, wherein a width of the notch groove and a plate thickness of the connection terminal are different.   9. The electric motor according to claim 8, wherein a width of the notch groove is larger than a plate thickness of the connection terminal.   9. The electric motor according to claim 8, wherein a width of the notch groove is smaller than a plate thickness of the connection terminal.

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