U.S. patent application number 09/803909 was filed with the patent office on 2001-10-04 for terminal structure of a motor.
This patent application is currently assigned to MINEBEA CO., LTD.. Invention is credited to Fujitani, Sakae, Harada, Naoyuki, Matsushita, Kunitake, Nakamata, Hirohito, Ohyashiki, Taketoshi, Shibata, Hiroichi, Suzuki, Yuzuru.
Application Number | 20010026103 09/803909 |
Document ID | / |
Family ID | 18609106 |
Filed Date | 2001-10-04 |
United States Patent
Application |
20010026103 |
Kind Code |
A1 |
Suzuki, Yuzuru ; et
al. |
October 4, 2001 |
Terminal structure of a motor
Abstract
A terminal of a motor is provided, in which a connection between
a coil and an external circuit can be carried out securely and with
a good workability, while saving material resources and enhancing
safety relating to environmental pollution. A terminal (23)
consists integrally of a magnet wire binding section (20) to
connect to a magnet wire (4) of a coil (6), an external connection
section (21) to connect to an external circuit and a support base
section (22) to press-fit into a terminal block (19) of a bobbin
(5) and hold the terminal (23), and the magnet wire (4) is plasma
welded for connection through to the external connection section
(21) (terminal 23). The connection of the terminal is carried out
by welding (plasma welding), thus the end of the magnet wire of a
motor (1) is connected without using solder containing lead. As a
result, since lead is not used, material resources can be saved and
safety relating to the environmental pollution can be enhanced.
Since the support base section (22) press-fits into a hole of the
terminal block (19) of the bobbin (5), a direction and position of
the terminal (23) are settled to thereby increase the
stability.
Inventors: |
Suzuki, Yuzuru; (Iwata-gun,
JP) ; Matsushita, Kunitake; (Iwata-gun, JP) ;
Shibata, Hiroichi; (Iwata-gun, JP) ; Harada,
Naoyuki; (Iwata-gun, JP) ; Ohyashiki, Taketoshi;
(Iwata-gun, JP) ; Fujitani, Sakae; (Iwata-gun,
JP) ; Nakamata, Hirohito; (Iwata-gun, JP) |
Correspondence
Address: |
OLIFF & BERRIDGE, PLC
277 S. WASHINGTON STREET, SUITE 500
ALEXANDRIA
VA
22314
US
|
Assignee: |
MINEBEA CO., LTD.
|
Family ID: |
18609106 |
Appl. No.: |
09/803909 |
Filed: |
March 13, 2001 |
Current U.S.
Class: |
310/71 |
Current CPC
Class: |
H02K 15/0068 20130101;
H02K 3/525 20130101; H02K 5/225 20130101; H02K 15/0056
20130101 |
Class at
Publication: |
310/71 |
International
Class: |
H02K 011/00 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 30, 2000 |
JP |
2000-94002 |
Claims
What is claimed is:
1. A terminal structure of a motor, said motor comprising: a stator
in which a coil, which is formed by winding a magnet wire around a
bobbin made of an insulating material, is inserted in a stator yoke
made of a soft magnetic material; and a rotor which includes a
permanent magnet, which is rotatably arranged in an inner
circumference of said stator, said terminal structure characterized
in that: said bobbin includes a terminal for connecting said coil
and an external circuit; and said terminal consists integrally of:
a magnet wire binding section to connect to the magnet wire of said
coil; an external connection section to connect to said external
circuit; and a support base section to press-fit into a terminal
block of said bobbin and hold said terminal.
2. A terminal structure of a motor according to claim 1, wherein at
least one of a projection and a recess for preventing said terminal
from pulling out from said terminal block of said bobbin is formed
at said support base section.
3. A terminal structure of a motor according to claim 1 or 2,
wherein a length of said external connection section is larger than
a length of said magnet wire binding section.
4. A terminal structure of a motor according to any one of claims 1
to 3, wherein the connection of said magnet wire binding section
and the magnet wire of said coil is carried out by means of
fusing.
5. A terminal structure of a motor according to any one of claims 1
to 3, wherein the connection of said magnet wire binding section
and the magnet wire of said coil is carried out by means of
resistance welding.
6. A terminal structure of a motor according to any one of claims 1
to 5, wherein: said support base section and said external
connection section are both formed in a rectangular shape and join
with each other in series longitudinally; said magnet wire binding
section is formed in a substantially L-shape with a first wing
thereof joining with a junction of said support base section and
said external connection section in such a manner that said first
wing thereof is perpendicular to said support base section and that
a second wing thereof is parallel with said external connection
section with a prescribed distance therebetween; and a length of
said second wing of said magnet wire binding section is set
different from a length of said external connection section.
7. A terminal structure of a motor according to claim 6, wherein:
an end of the magnet wire of said coil is bound around said second
wing of said magnet wire binding section; and a length of said
second wing of said magnet wire binding section is set so that a
distance from an end of the binding of the magnet wire to a tip end
of said second wing of said magnet wire binding section falls
within a range of 0.5 to 3 mm.
8. A terminal structure of a motor according to any one of claims 1
to 5, wherein: said support base section and said external
connection section are both formed in a rectangular shape and join
with each other in series longitudinally; said magnet wire binding
section is formed in a substantially L-shape with a first wing
thereof joining with a junction of said support base section and
said external connection section in such a manner that said first
wing thereof is perpendicular to said support base section and that
a second wing thereof is parallel with said external connection
section with a prescribed distance therebetween; a length of said
external connection section is set larger than a length of said
second wing of said magnet wire binding section; and a junction of
said support base section, said external connection section and
said first wing of said magnet wire winding section, as well as
said support base section, press-fits into said terminal block of
said bobbin.
9. A terminal structure of a motor according to claim 8, wherein:
the end of the magnet wire of said coil is bound around said second
wing of said magnet wire binding section; and a length of said
second wing of said magnet wire binding section is set so that a
distance from an end of the binding of the magnet wire to a tip end
of said second wing of said magnet wire binding section falls
within a range of 0.5 to 3 mm.
10. A terminal structure of a motor according to any one of claims
1 to 9, wherein a lead terminal to connect said external connection
section and said external circuit is connected to said external
connection section by means of resistance welding.
11. A terminal structure of a motor according to claim 10, wherein
a groove into which said lead terminal fits is provided at a tip
end of said external connection section.
12. A terminal structure of a motor according to claim 10, wherein
said lead terminal widens at an end joining with said external
connection section, and a groove into which said external
connection section fits is provided at the center of the end.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to a terminal structure
employed in an inner rotor-type motor, and more particularly, to a
terminal structure of a motor suitable for connection by
welding.
[0003] 2. Description of the Related Art
[0004] In recent years, from demands for environmental
pollution-control measures, etc., solder for welding or attaching
various kinds of parts is desired to be lead-free. Accordingly,
research on lead-free solder (solder containing no lead) has been
actively carried out. Use of lead-free solder also for connecting
ends of a magnet wire of a motor coil is being considered.
[0005] For instance, in case of a PM-type stepping motor, after a
an end part of a magnet wire from a coil is bound several turns
around a terminal press-fitted into a terminal block (bobbin), the
terminal is dipped in a solder bath filled with molten solder to
detach an insulation coating from the magnet wire and at the same
time to connect a copper lead wire as a core wire and the terminal
by means of soldering, wherein the above mentioned lead-free solder
is expected to be used.
[0006] However, though the lead-free solder is expected to be used
in the connection of the end of magnet wire of the PM-type stepping
motor, the molten lead-free solder suffers an intense oxidization
and becomes brittle (so-called cold solder) unless placed in a
reduced atmosphere of nitrogen. Thus, its reliability cannot be
ensured and the lead-free solder has not been adopted.
[0007] The lead-free solder, from the viewpoint of its
characteristics, is subject to various restrictions such as a
method of use and its solderability with objects to be soldered,
and further, compared with a conventional eutectic-type solder, has
a higher melting point, is more liable to cause a problem like a
poor contact, requires a higher level of soldering technique, is
more difficult to use, and is more expensive as well. So, an
alternative to the lead-free solder has been under
consideration.
SUMMARY OF THE INVENTION
[0008] The present invention has been made in view of the
above-mentioned circumstances, and therefore has an object to
provide a motor terminal having a structure which enables a coil
and an external circuit to be connected securely and with a good
workability, while saving material resources and increasing safety
relating to environmental pollution.
[0009] According to a first aspect of the present invention, there
is provided a terminal structure for a motor which comprises a
stator in which a coil formed by winding a magnet wire around a
bobbin made of an insulating material is inserted in a stator yoke
made of a soft magnetic material and a rotor which includes a
permanent magnet rotatably arranged in an inner circumference of
the stator, the terminal structure characterized in that the bobbin
includes a terminal for connecting the coil and an external circuit
and that the terminal consists integrally of a magnet wire binding
section to connect to the magnet wire of the coil, an external
connection section to connect to the external circuit and a support
base section to press-fit into a terminal block (bobbin) and hold
the terminal onto the block.
[0010] That is, in the first aspect of the present invention, the
terminal is structured into three sections by function. The first
is the magnet wire binding section that does a function of a
terminal to connect to the magnet wire from the coil wound around
the bobbin, the second is the external connection section that has
a function of a terminal to connect to the external circuit, and
the third is the support base section that press-fits into the
terminal block and hold the terminal onto the block. While these
three sections are adapted to be handled independently of each
other, they are structured integrally so as to be handled as a
single terminal.
[0011] The reason for employing the structure of the terminal
composed of three sections is as follows. When connecting an end of
magnet wire, that is, connecting, by means of fusing (plasma
welding), the magnet wire bound around the magnet wire binding
section to the terminal, a discharge current resulting from plasma
welding must be allowed to flow, and therefore a ground electrode
of a plasma welding machine is connected to the external connection
section which is electrically continuous with a welded portion,
thereby enabling the welding operation and also enabling the
terminal to connect externally without getting melted or deformed
by the welding.
[0012] Note that the terminal may be so structured that a direction
and position of the terminal may be settled by press-fitting a
junction of the magnet wire binding section, the external
connection section and the support base section, together with the
support base section, into a guide hole and a groove provided in
the terminal block.
[0013] According to a second aspect of the present invention, in
the terminal structure according to the first aspect of the present
invention, at least one of a projection and a recess, for
preventing the terminal from pulling out from the terminal block,
is formed at the support base section.
[0014] According to a third aspect of the present invention, in the
terminal structure according to the first or second aspect of the
present invention, the length of the external connection section is
greater than the length of the magnet wire binding section.
[0015] The reason the length of the external connection section is
set greater than that of the magnet wire bending section is, to
make the connection of the ground electrode easier when connecting
the magnet wire from the coil onto the magnet wire binding section
by plasma welding, and make the external connection of the terminal
easier. The length of the external connection section may be set
equivalent to the length of the magnet wire binding section.
[0016] According to a fourth aspect of the present invention, in
the terminal structure according to any one of the first to third
aspects of the present invention, the connection of the magnet wire
binding section and the magnet wire of the coil is carried out by
means of fusing.
[0017] According to a fifth aspect of the present invention, in the
terminal structure according to any one of the first to third
aspects of the present invention, the connection of the magnet wire
binding section and the magnet wire of the coil is carried out by
resistance welding.
[0018] According to a sixth aspect of the present invention, in the
terminal structure according to any one of the first to fifth
aspects of the present invention, the support base section and the
external connection section are both formed in a rectangular shape
and connected to each other in series longitudinally, the magnet
wire binding section is formed in a substantially L-shape with a
first wing thereof joining with the junction of the support base
section and the external connection section in such a manner that
the first wing is perpendicular to the support base section and
that a second wing thereof is parallel with the external connection
section with a given distance therebetween, and the length of the
second wing is set different from that of the external connection
section.
[0019] According to a seventh aspect of the present invention, in
the terminal structure according to the sixth aspect of the present
invention, an end portion of magnet wire of the coil is bound
around the second wing of the magnet wire binding section and the
length of the second wing is set so that the distance from an end
of the binding of the magnet wire to a tip end of the second wing
falls within a range of 0.5 to 3 mm.
[0020] According to an eighth aspect of the present invention, in
the terminal structure according to any one of the first to fifth
aspects of the present invention, the support base section and the
external connection section are both formed in a rectangular shape
and connected to each other in series longitudinally, the magnet
wire binding section is formed in a substantially L-shape with a
first wing thereof joining with the conjunction of the support base
section and the external connection section in such a manner that
the first wing is perpendicular to the support base section and
that a second wing thereof is parallel with the external connection
section with a given distance therebetween, the length of the
external connection section is set larger than the length of the
second wing, and the junction of the support base section, the
external connection section and the first wing of the magnet wire
binding section, as well as the support base section, is adapted to
press-fit into the terminal block (bobbin).
[0021] According to a ninth aspect of the present invention, in the
terminal structure according to the eighth aspect of the present
invention, the tip end of magnet wire of the coil is bound around
the second wing of the magnet wire binding section, and the length
of the second wing is set so that the distance from an end of the
binding of the magnet wire to a tip end of the second wing falls
within a range of 0.5 to 3 mm.
[0022] According to a tenth aspect of the present invention, in the
terminal structure according to any one of the first to ninth
aspects of the present invention, a lead terminal for bridging the
external connection section and the external circuit is connected
to the external connection section by resistance welding.
[0023] According to an eleventh aspect of the present invention, in
the terminal structure according to the tenth aspect of the present
invention, a groove into which the lead terminal fits is provided
at the tip end of the external connection section.
[0024] According to a twelfth aspect of the present invention, in
the terminal structure according to the tenth aspect of the present
invention, the lead terminal is set wider at an end joining with
the external connection section, and a groove is provided at the
center of the wider portion for fixing the external connection
section.
BRIEF DESCRIPTION OF THE DRAWINGS
[0025] In the accompanying drawings:
[0026] FIG. 1 is a sectional view (taken along a line A-A of FIG.
2) of a motor with a terminal structure according to a first
embodiment of the present invention;
[0027] FIG. 2 is a bottom view of the motor of FIG. 1.
[0028] FIG. 3 is a partial view of the motor of FIG. 2 viewed from
an arrow B;
[0029] FIG. 4 is a plan view of a bobbin of FIG. 1;
[0030] FIG. 5 is a bottom view of the bobbin of FIG. 4;
[0031] FIG. 6 is a schematic view of a state haw an end of a magnet
wire of a coil is bound around a magnet wire binding section of
FIG. 1;
[0032] FIG. 7 is a front view of a lead terminal;
[0033] FIG. 8 is a plan view of a second embodiment of the present
invention;
[0034] FIG. 9 is a plan view of a third embodiment of the present
invention;
[0035] FIG. 10 is a plan view of a fourth embodiment of the present
invention;
[0036] FIG. 11 is a perspective view of a fifth embodiment of the
present invention; and
[0037] FIG. 12 is a perspective view of a sixth embodiment of the
present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0038] A first embodiment of the present invention will be
explained with reference to FIGS. 1 to 7.
[0039] In FIGS. 1 to 3, a PM-type stepping motor (inner rotor-type
stepping motor) 1 includes stator yokes 2, 3, which are made of
steel of a soft magnetic material and pressed to be formed in a
donut-shape. On an inner circumference of the stator yokes 2, 3,
pole teeth shaped like a comb (not shown) are provided. The stator
yokes 2, 3 encase a coil 6, which is formed by winding a magnet
wire 4 around a bobbin 5, and constitute a stator assembly 7 in
association with the coil 6.
[0040] Two stator assemblies 7, 7 are put together with one on
another as shown in FIG. 1. There are provided two bobbins 5, 5 to
mate the two stator assemblies 7, 7, respectively.
[0041] A front plate 8 and a rear plate 9 are fixed onto the stator
assemblies 7, 7 in such a manner as to cover a space defined by the
inner circumference of the stator yokes 2, 3.
[0042] A rotor 10 is provided inside the stator assemblies 7, 7.
The rotor 10 includes a shaft 11 as a rotation axis and a permanent
magnet 12 having a plurality of magnetic poles on the circumference
thereof opposite to the comb-like pole teeth formed on the inner
circumference of the stator yokes 2, 3.
[0043] The shaft 11 is press-fitted into a sleeve 13. The permanent
magnet 12 and the sleeve 13 (meaning also shaft 11) are fixedly
held together with a holder 14 made of a high polymer material.
[0044] The rear plate 9 is molded with PBT resin, a kind of high
polymer, integrally with the two stator assemblies 7, 7 put
together back to back. In this process, a hole 15 for bearing as an
axis of rotation and a diameter of the inner circumference of the
stator assemblies 7, 7, where the comb-like pole teeth are
provided, are simultaneously formed with a same mandrel.
Accordingly, its highly-precise coaxiality can be ensured.
[0045] The bobbin 5 is made of a high polymer material such as the
PBT resin. The bobbin 5 generally comprises, as shown in FIGS. 4
and 5, a cylinder 16 and approximately annular flanges 17, 17
provided at both ends of the cylinder 16 and projecting radially
outward. One flange 17 (lower side in FIG. 4) of the two flanges
17, 17 includes an approximately annular flange proper 18 and a
terminal block 19 formed on a portion (near a terminal 23 to be
described later) of the flange proper 18 and substantially
rectangular in a plan view (See FIG. 5).
[0046] The terminal block 19 projects outward in a radial direction
from the flange proper 18 and is set larger in thickness than the
flange proper 18. As described above, two bobbins 5 are provided,
and hence two terminal blocks 19 are provided. The two terminal
blocks 19 are put together, as shown in FIGS. 1 and 3.
[0047] Two terminals 23 made of phosphorous bronze and consisting
integrally of a magnet wire binding section 20, an external
connection section 21 and a support base section 22 are
press-fitted into the terminal block 19 of the bobbin 5. The motor
1 is adapted to include 4 terminals 23, as shown in FIG. 3, as the
motor has two bobbins 5 each including two terminals 23.
[0048] A lead terminal 24 connecting to an external circuit is
connected to each of the four terminals 23. Four lead terminals 24
go through a lead terminal holder 25 which projects from the front
plate 8. The rearward projection lengths of the four lead terminals
24 from the lead terminal holder 25 are determined to the positions
of the terminals 23 to be connected to.
[0049] The magnet wire binding section 20 of the terminal 23,
around which the magnet wire 4 of the coil 6 is bound several
turns, is plasma welded for connection with the magnet wire 4 and
for holding the same, to thereby improve the reliability of winding
and the workability of handling.
[0050] The external connection section 21 fits into a groove 26
(See FIG. 7) provided on a tip end of the lead terminal 24 to
connect externally with a tip end thereof projecting from the lead
terminal 24, is crimped with the lead terminal 24 and plasma-welded
for connection.
[0051] The support base section 22 is adapted to fit into a hole 27
and a groove 28 continuous therewith which are formed in the
terminal block 19 of the bobbin 5, thereby supporting the terminal
23 onto the terminal block of the bobbin 5 precisely.
[0052] The support base section 22 and the external connection
section 21 are both formed in a rectangle shape, and join with each
other in series (the portion is referred to as junction 29 "joining
portion") The magnet wire binding section 20 is formed in an
approximately L shape. One wing (first wing 20a) of the magnet wire
binding section 20 joins with the junction 29 in such a manner that
the first wing 20a is perpendicular to the support base section 22
and that other wing (second wing 20b) of the magnet wire binding
section 20 is parallel with the external connection section 21 with
a given distance therebetween.
[0053] The length of the external connection section 21 is set
larger than that of the second wing 20b of the magnet wire binding
section 20 as shown in FIGS. 5 and 6.
[0054] The magnet wire 4 of the coil 6 (end of the coil 6) is bound
(referred to as binding 30) several turns around the second wing
20b of the magnet wire binding section 20 upon winding. The length
of the magnet wire of the coil 6 is set so that the distance H from
the end of the binding 30 of the magnet wire 4 to the tip end of
the second wing 20b falls within a range of 0.5 to 3 mm.
[0055] This is required to enable connection by means of fusing
(connection by plasma welding). The fusing connection is carried
out as follows. First, the second wing 20b of the magnet wire
binding section 20 is melted, and an insulating coating on the
magnet wire 4 of the coil 6 is thermally peeled off with this
molten metal, whereby a copper wire as a core wire is connected to
the second wing 20b. If the distance between the tip end of the
second wing 20b and the end of the binding 30 is too short or zero,
the magnet wire 4 of the coil 6 is sublimed due to the energy of
plasma (arc) and the connection is prohibited. In order to avoid
this problem (failure of connection), the above-mentioned distance
H is set 0.5 mm or longer.
[0056] Further, if the distance H is set longer than 3 mm, the
molten metal does not reach the magnet wire 4 of the coil 6, and
thus the connection does not happen. To avoid this problem, the
distance H is set 3 mm maximum.
[0057] A widened portion 31 is formed at the end of the lead
terminal 24, as shown in FIG. 7, and at the center of the widened
portion 31 the groove 26 is provided for receiving the external
connection section 21. The external connection section 21 fits into
the groove 26 with its tip end projecting, is crimped with the
terminal 23 and connected to the lead terminal 24 by plasma
welding. In this embodiment, the lead terminal 24 is grounded at
the time of welding.
[0058] The magnet wire 4 of the coil 6 is connected to the external
circuit through the terminal 23 press-fitted into the terminal
block 19 and the lead terminal 24.
[0059] In this PM-type stepping motor 1, the two stator assemblies
7, 7 are joined to each other back to back, and the stator formed
by this joining is molded integrally with the rear plate 9 using a
PBT resin (a polymer material). At this point, the hole 15 for
bearing as a rotation axis and the comb-like pole teeth provided on
the inner circumference of the stator assemblies 7, 7 are formed
simultaneously using a unitary type of mandrel. As a result, this
PM-type stepping motor 1 guarantees a highly-precise
coaxiality.
[0060] In the PM stepping motor 1 constituted as mentioned above,
the terminal 23 consists integrally of the magnet wire binding
section 20 to connect to the magnet wire 4 of the coil 6, the
external connection section 21 to connect to the external circuit,
and the support base section 22 to press-fit into the terminal
block 19, wherein the magnet wire 4 is plasma welded for connection
through to the external connection section 21 (terminal 23),
thereby carrying out the connection of the terminal of the motor 1
by means of welding (plasma welding). Thus, since the terminal is
connected without using solder containing lead, safety in regards
to pollution is improved to that extent.
[0061] Since the external connection section 21 fits into the
groove 26 of the lead terminal 24, the lead terminal 24 and the
external connection section 21 (terminal 23) are brought into
secure and stable contact. As a result, plasma welding is carried
out stably. Further, since the external connection section 21 fits
into the groove 26 of the lead terminal 24 whereby the external
connection section 21 and the lead terminal 24 contact with each
other securely and stably, an electrical continuity is ensured. In
this case, after the end of the external connection section 21 fits
into the groove 26 of the lead terminal 24, the tip end is crimped
with the lead terminal 24. Thus the contact between the external
connection section 21 and the lead terminal 24 is further secured,
resulting in an improvement in its electrical continuity.
[0062] In connecting the terminal of a motor using lead-free
solder, there has been a concern that a high technique required for
soldering will lower the workability and increase the cost of
equipment. In the present embodiment, the terminal of the motor 1
is connected by welding (plasma welding), and therefore the
reduction in the workability of connecting the terminal of the
motor 1 and the cost increase for the apparatus due to lead-free
soldering can be avoided.
[0063] Further, in this embodiment, since the terminal of the motor
1 is connected by plasma welding, the insulation coating of the
magnet wire 4 can be peeled off effectively.
[0064] Further, since the terminal 23 consists integrally of the
magnet wire binding section 20, the external connection section 21
and the support base section 22 and since the support base section
22 press-fits into the hole 27 of the terminal block 19 (outer
surface of the bobbin 5), the direction and position of the
terminal 23 are settled securely, to thereby increase the
stability. For reference, in this embodiment, the support base
section 22 fits into the hole 27 and at the same time the first
wing 20a of the magnet wire binding section 20, as well as the
junction 29, fits into the groove 28 thereby press-fitting the
terminal 23 into the terminal block 19, so the direction and
position of the terminal 23 can be settled further securely and
stably.
[0065] Further, since the distance H from the end of the binding 30
to the tip end of the second wing 20b of the magnet wire binding
section 20 is set to fall within a range of 0.5 to 3 mm, it can be
prevented from happening that the magnet wire 4 of the coil 6 is
sublimed due to the energy of plasma (arc) and that the molten
metal does not reach the magnet wire 4, leading to a failure in
connection. Thus, good welding is ensured.
[0066] The length of the external connection section 21 is set
larger than that of the second wing 20b of the magnet wire binding
section 20. Therefore, the external connection section 21 can be
connected to the lead terminal 24 easier, and the interference
thereof can be reduced to a minimum allowing the external
connection section 21 to be bent at a right angle, for instance. To
that extent, usage is expanded for flexible application. When the
external connection section 21 is bent as mentioned above, it may
arise that the terminal 23 is too long, resulting in deterioration
in the workability. In such a case, the terminal 23 is connected to
the lead terminal 24 while holding the terminal 23, for instance,
on a flange provided separately for stabilization, whereby the
deterioration of the workability can be prevented.
[0067] The terminal 23 is not limited to the above embodiment, but
a terminal 23A (second embodiment) shown in FIG. 8, a terminal 23B
(third embodiment) shown in FIG. 9 and a terminal 23C (fourth
embodiment) shown in FIG. 10 may be used.
[0068] In a second embodiment, as shown in FIG. 8, the support base
section 22 of the terminal 23A is provided with a wedge-like
projection 40 that prevents the terminal 23A from pulling out from
the terminal block 19, and the hole 27 in the terminal block 19
(outer surface of the bobbin 5) is provided with an engaging
portion (not shown) to catch the projection 40.
[0069] According to the second embodiment, the pulling-out strength
of the terminal 23A is increased due to the projection 40 being
caught by the engaging portion (not shown). As a result, even when
the length of the support base section 22 is short, the terminal
23A is held securely.
[0070] Note that a recess (not shown) instead of the projection 40
may be formed at the support base section 22, and a projection as
an engaging portion for the engagement with the recess may be
provided on the wall of the hole 27 in the terminal block 19.
Further, both a projection and a recess (not shown) are formed on
the support base section 22, and an engaging portion to engage with
the projection and the recess may be provided on the wall of the
hole 27 in the terminal block 19.
[0071] In the terminal 23B of a third embodiment, as shown in FIG.
9, the width (area) of the external connection section 21 is set
larger than the width (area) of the support base section 22.
[0072] According to the third embodiment, the area of the external
connection section 21 contacting with the lead terminal 24 is
increased, whereby the lead terminal 24 and the external connection
section 21 can be welded securely and stably.
[0073] Ina fourth embodiment, as shown in FIG. 10, a cutout 41
(groove) is formed at the tip end of the external connection
section 21 and the tip end of the lead terminal 24 fits into the
cutout 41 and crimped to make the contact therebetween secure and
stable, resulting in a stable welding. Note that, the groove 26,
which is formed at the tip end of the lead terminal 24 in the first
embodiment as shown in FIG. 7, is not formed when the cutout 41 is
formed at the tip end of the external connection section 21 as in
the case of the fourth embodiment.
[0074] In each of the above embodiments the connection between the
lead terminal 24 and the external connection section 21 is carried
out by plasma welding, but resistance welding may be used. Note
that in the case of using the resistance welding, a face of the
external connection section 21 and a face of the lead terminal 24
are adapted to partly overlap each other, so the external
connection section 21 and the lead terminal 24 are set a little
longer for the area of overlapping. With such a setting, a stable
welding is enabled. Further, when using the resistance welding, the
terminal 23 is preferably formed of a ferrous material.
[0075] In FIG. 11, an example of the resistance welding (fifth
embodiment) is shown.
[0076] In a fifth embodiment, the external connection section 21
and the lead terminal 24 are positioned so as to partly overlap
each other, and the overlap portion is clamped and pressed with
electrodes 43, 43 of a resistance welding machine 42, then a
current is applied to complete the welding. Thus, the external
connection section 21 and the lead terminal 24 are connected.
[0077] Such a resistance welding as illustrated in the fifth
embodiment can be performed when the external connection section 21
and the lead terminal 24 are positioned so as to overlap as shown
in FIG. 11. However, in the case where the external connection
section 21 and the lead terminal 24 can not be positioned so as to
overlap each other due to a space constraint, a resistance welding
(sixth embodiment) shown in FIG. 12 can be employed to connect the
external connection section 21 and the lead terminal 24.
[0078] In a sixth embodiment, the lead terminal 24 is positioned
with an end face thereof in contact with a face (upper face in FIG.
12) of the external connection section 21 and welded. In this case,
when the area of the face of the external connection section 21 is
large, there is an easier contact with the end face of the lead
terminal 24. Accordingly, the workability is improved. Further, by
increasing the area of the face of the external connection section
21, the connection can be carried out stably even if the contact
position to the lead terminal 24 varies some or less.
[0079] Further, according to this sixth embodiment, even if it
cannot happen due to a space constraint that the external
connection section 21 and the lead terminal 24 are positioned to
overlap each other (for example, as shown in FIG. 11), the
connection between the external connection section 21 and the lead
terminal 24 can be successfully achieved.
[0080] Note that, in each of the above embodiments the material of
the terminal 23 is a phosphorous bronze, but the present invention
is not limited to this material, but other materials such as a
copper alloy may be used.
[0081] According to the first aspect of the present invention, a
terminal consists integrally of a magnet wire binding section to
connect to a magnet wire of a coil, an external connection section,
and a support base section to press-fit into a terminal block. As
the support base section press-fits into the terminal block, the
direction and position of the terminal are settled with the result
that the stability is increased.
[0082] Further, since the terminal is divided into the three
sections, a ground electrode of a plasma welding machine is
connected to the external connection section, which is electrically
continuous with the welding portion, whereby discharge current
caused by plasma welding is allowed to flow. So, a magnet wire
bound around the magnet wire binding section can be connected by
means of fusing (plasma welding), with the result that the
connection of the motor terminal can be carried out without using
solder containing lead thereby saving material resources. At the
same time, since lead is not used, the safety relating to the
environmental pollution can be enhanced.
[0083] According to the second aspect of the present invention,
since a projection and/or a recess for preventing the terminal from
pulling out are provided on the support base section, the force of
engaging with the terminal block is increased. As a result, the
terminal can be held more stably to the terminal block.
[0084] According to the third aspect of the present invention, the
length of the external connection section is set larger than that
of the magnet wire binding section. As a result, the connection of
the ground electrode can be made easier when the magnet wire of the
coil is plasma welded for connection to the magnet wire binding
section, and at the same time the terminal can be externally
connected easily.
[0085] According to the fourth aspect of the present invention, the
magnet wire binding section and the magnet wire of the coil are
connected by means of fusing (plasma welding), with the result that
the connection of the motor terminal is carried out without using
solder containing lead. As a result, material resources can be
saved and the safety relating to the environmental pollution can be
enhanced.
[0086] According to the fifth aspect of the present invention, the
magnet wire binding section and the magnet wire of the coil are
connected by resistance welding, with the result that the
connection of the motor terminal is carried out without using
solder containing lead. As a result, material resources can be
saved and the safety relating to the environmental pollution can be
enhanced.
[0087] According to the sixth aspect of the present invention, the
external connection section may be set longer than a second wing of
the magnet wire binding section. As a result, the lead terminal and
the external connection section can partly overlap and also the
resistance welding thereof is made easier.
[0088] According to the seventh or ninth aspect of the present
invention, the distance from the end of the binding of the magnet
wire of the coil to the tip end of the second wing of the magnet
wire binding section is set 0.5 mm or longer. As a result, the
magnet wire of the coil can be prevented from subliming due to the
energy of plasma (arc), enabling the magnet wire of the coil to be
connected to the magnet wire binding section by plasma welding. In
addition, since the distance is set 3 mm maximum, it does not
happen that molten metal fails to reach the magnet wire, ensuring
that the magnet wire of the coil is connected to the magnet wire
binding section by plasma welding.
[0089] According to the eighth aspect of the present invention, a
junction of the support base section, the external connection
section and a first wing of the magnet wire binding section, as
well as the support base section, press-fits into the terminal
block. As a result, the terminal is positioned duly and at the same
time held securely, improving the workability.
[0090] According to the tenth aspect of the present invention, the
connection of the lead terminal and the external connection section
is carried out by resistance welding. Therefore, material sources
can be saved and welding can be done with a relatively general
purpose equipment, resulting in reducing the cost of welding work
and the cost of appliance.
[0091] According to the eleventh aspect of the present invention,
the lead terminal press-fits into a groove provided at the tip end
of the external connection section. As a result, the welding
between the lead terminal and the external connection section can
be carried out securely and stably, and at the same time the
welding work can be done easily.
[0092] According to the twelfth aspect of the present invention,
the external connection section can be guided to a groove at the
widened portion of the lead terminal. As a result, the welding
between the lead terminal and the external connection section can
be carried out securely and stably.
* * * * *