Information
-
Patent Grant
-
6564443
-
Patent Number
6,564,443
-
Date Filed
Monday, July 9, 200123 years ago
-
Date Issued
Tuesday, May 20, 200321 years ago
-
Inventors
-
Original Assignees
-
Examiners
Agents
-
CPC
-
US Classifications
Field of Search
US
- 029 596
- 335 260
- 335 299
-
International Classifications
-
Abstract
An accommodating base material and an attracting base material are coaxially arranged, and are resin-insert-molded, thereby forming a bobbin base material. Next, inner peripheries of the accommodating base material, attracting base material and bobbin base material are cut, so that the accommodating base material, attracting base material and bobbin base material have same inner diameters. As a result of the cut-forming process, an accommodating member, an attracting member and a bobbin are formed. After insert-molding, the accommodating base material, attracting base material and bobbin base material are cut to have the same inner diameters. Thus, the accommodating member and the attracting member are accurately coaxially formed.
Description
CROSS REFERENCE TO RELATED APPLICATION
This application is based on and incorporates herein by reference Japanese Patent Application No. 2000-209778 filed on Jul. 11, 2000.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a method for manufacturing an electromagnetic operating apparatus.
2. Description of Related Art
JP-A-10-299932 discloses an electromagnetic operating apparatus in which a first yoke and a second yoke are formed independently from each other. In the electromagnetic operating apparatus, a bobbin around which a soil is wound supports a plunger as a moving core. Thus, even when axes of the first and second yokes are diverted from each other, the plunger is not prevented from reciprocating.
U.S. Pat. No. 5,769,391 discloses an electromagnetic valve in which an accommodating member and an attracting member are integrally formed to provided a stator core. In the electromagnetic valve, since there is no assembling error, the accommodating member and the attracting member are accurately coaxially arranged. However, when thickness of a connecting portion between the accommodating member and the attracting member is small, the stator core might be transformed by a force forming a resin bobbin at outer peripheries of the accommodating member and the attracting member, or by a force for winding a coil around the bobbin. If the thickness of the connecting portion is set to large for preventing the transformation of the stator core, an amount of magnetic flux flowing between the accommodating member and the attracting member via the connecting portion increases. Whereby, generated magnetic force becomes small relative to an electric current supplied into the coil.
SUMMARY OF THE INVENTION
An object of the present invention is to arrange an accommodating member and an attracting member accurately coaxially, and to increase an attracting force generated between the attracting member and a moving core.
According to a first aspect of the present invention, an accommodating base material and an attracting base material, which is independent from the accommodating base material, are resin-insert-molded. After that, the accommodating and attracting base materials are processed to form an accommodating member and an attracting member to accommodate a moving core such that the moving core reciprocates therein. Even if axes of the accommodating base material and attracting base material are diverted from each other when they are insert-molded, the accommodating member and attracting member are accurately coaxially arranged by processing the accommodating and attracting base materials after the insert-molding. Thus, a radial clearance between the accommodating member and the moving core, and between the attracting member and the moving core are made as small as possible, thereby increasing a force attracting the moving core.
According to a second aspect of the present invention, the accommodating and attracting base materials are processed after winding the coil around the bobbin. Thus, a force for winding the coil around the bobbin does not act on the accommodating member and the attracting member. As a result, axes of the accommodating member and the attracting member are prevented from being diverted from each other.
According to a third aspect of the present invention, a stator core base material, which includes base materials of the accommodating member and attracting member, and which includes a thin thick portion integrally formed to connect the base materials to each other, is resin-insert-molded. After that, the resin-insert-molded stator core base material is processed for forming a stator core to accommodate the moving core such that the moving core reciprocates therein. Even when axes of the accommodating base material and attracting base material are diverted from each other due to a pressure during the insert-molding, the accommodating member and attracting member are accurately coaxially arranged by processing the stator core base material after the insert-molding. Thus, a radial clearance between the accommodating member and the moving core, and between the attracting member and the moving core are made as small as possible, thereby increasing a force attracting the moving core.
BRIEF DESCRIPTION OF THE DRAWINGS
Additional objects and advantages of the present invention will be more readily apparent from the following detailed description of preferred embodiments thereof when taken together with the accompanying drawings in which:
FIG. 1
is a cross-sectional view showing an electromagnetic valve (first embodiment);
FIGS. 2A-2C
are cross-sectional views showing a manufacturing process of an accommodating member, an attracting member and a bobbin (first embodiment);
FIGS. 3A-3C
are cross-sectional views showing a manufacturing process of an accommodating member, an attracting member and a bobbin (second embodiment);
FIG. 4
is a cross-sectional view showing an electromagnetic valve (third embodiment);
FIGS. 5A-5C
are cross-sectional views showing a manufacturing process of an accommodating member, an attracting member and a bobbin (third embodiment);
FIGS. 6A-6C
are cross-sectional views showing a manufacturing process of an accommodating member, an attracting member and a bobbin (fourth embodiment), and
FIG. 7
is a cross-sectional view showing an electromagnetic valve (fifth embodiment).
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
(First Embodiment)
FIG. 1
shows an electromagnetic valve
1
including an electromagnetic operating apparatus in the first embodiment.
The electromagnetic valve
1
is a spool type oil pressure control valve to control an oil pressure of working oil. The working oil is supplied to an oil pressure control apparatus used for an automatic transmission of vehicle.
A linear solenoid
10
works as the electromagnetic operating apparatus, and includes a yoke
11
, an accommodating member
13
, an attracting member
14
, a plunger
17
, a shaft
18
, and a coil
20
. The yoke
11
is cylindrically formed and has a bottom. The plunger
17
works as a moving core. The yoke
11
, accommodating member
13
and attracting member
14
form a stator core. The yoke
11
, accommodating member
13
, attracting member
14
and plunger
17
are made of magnetic material, and form a magnetic circuit.
A housing
31
supports a spool
30
such that the spool
30
reciprocates therein. The yoke
11
is mechanically fixed to the housing
31
to fix the attracting member
14
between the yoke
11
and the housing
31
.
The accommodating member
13
supports the plunger
17
such that the plunger
17
reciprocates therein. Nickel-phosphorus plating is provided on the inner wall of the accommodating member
13
to reduce a sliding resistance between the plunger
17
and the inner wall of the accommodating member
13
.
The attracting member
14
generates an attracting force and includes a guide portion
14
a
for guiding the plunger
17
. When the coil
20
is energized, the attracting member
14
generates the attracting force to attract the plunger
17
. A stopper
15
made of nonmagnetic material is provided at a top face of the attracting member
14
axially facing the plunger
17
.
Top end of the shaft
18
is press-inserted into the plunger
17
. Bottom end of the shaft
18
contacts a top end of the spool
30
.
The coil
20
is wound around a bobbin
21
made of resin. When an electric current is supplied into the coil
20
through a terminal (not illustrated) electrically connected to the coil
20
, a magnetic flux flows in the magnetic circuit, thereby generating a magnetic attracting force between the attracting member
14
and the plunger
17
. Then, the plunger
17
and the shaft
18
move downwardly in FIG.
1
. Downward movement of the plunger
17
is restricted by the stopper
15
.
The spool
30
always contacts the shaft
18
of the linear solenoid
10
. The movement of the plunger
17
is transmitted to the spool
30
through the shaft
18
, and the spool
30
reciprocates in the housing
31
. The housing
31
includes an inlet port
32
, an outlet port
33
, a feedback port
34
, and a discharge port
35
. A pump feeds the working oil from a tank (not illustrated) to the inlet port
32
. The working oil is supplied from the outlet port
33
to an engaging device of the automatic transmission. The outlet port
33
communicates with the feedback port
34
at the outside of the electromagnetic valve
1
. The working oil discharged from the outlet port
33
is partially introduced into the feedback port
34
. A feedback chamber
36
communicates with the feedback port
34
. The working oil is discharged from the discharge port
35
into the tank.
The spool
30
includes a first large diameter land
37
, a second large diameter land
38
, and small diameter land
39
orderly from the bottom side (opposite liner solenoid side) thereof. An outer diameter of the small diameter land
39
is smaller than those of the large diameter lands
37
and
38
.
The feedback chamber
36
is formed between the second large diameter land
38
and the small diameter land
39
. Since the outer diameters of these lands
38
,
39
are different, surface areas on which pressure of the feed-backed working oil acts are different. Thus, the oil pressure in the feedback chamber
36
presses the spool
30
downwardly in FIG.
1
. In the electromagnetic valve
1
, the discharged oil pressure is partially feed-backed for preventing a discharged oil pressure fluctuation due to a supplied oil pressure fluctuation. The spool
30
is placed at a position where an urging force of the spring
40
, a force of the shaft
18
pressing the spool
30
when the attracting member
14
attracts the plunger
17
due to the electric current supplied into the coil
20
, and a force the spool
30
receives from the oil pressure in the feedback chamber
36
are balanced.
The spring
40
is provided at the bottom (opposite linear solenoid side) of the spool
30
, and urges the spool
30
upwardly, i.e., toward the linear solenoid
10
. An adjust screw
41
adjusts a load of the spring
40
in accordance with the screwed amount thereof.
An amount of the working oil flowing from the inlet port
32
to the outlet port
33
is determined based on a seal length between an inner wall
31
a
of the housing
31
and an outer wall of the second large diameter land
38
. The seal length means an overlapped length between the inner wall
31
a
of the housing
31
and an outer wall of the second large diameter land
38
. As the seal length decreases, the working oil amount flowing from the inlet port
32
to the outlet port
33
increases. As the seal length increases, the working oil amount flowing from the inlet port
32
to the outlet port
33
decreases. Similarly, working oil amount flowing from the outlet port
33
to the discharge port
35
is determined based on a seal length between the inner wall
31
b
of the housing
31
and an outer wall of the first large diameter land
37
.
When the coil
20
is energized, the spool
30
moves downwardly in
FIG. 1
, i.e., toward the spring
40
. Since the seal length between the inner wall
31
a
and the second large diameter land
38
increases and the seal length between the inner wall
31
b
and the first large diameter land
37
decreases, the working oil amount flowing from the inlet port
32
to the outlet port
33
decreases and the working oil amount flowing from the outlet port
33
to the discharge port
35
increases. As a result, the pressure of the working oil discharged from the outlet port
33
decreases.
When the spool
30
moves toward the linear solenoid
10
, since the seal length between the inner wall
31
a
and the second large diameter land
38
decreases and the seal length between the inner wall
31
b
and the first large diameter land
37
increases, the working oil amount flowing from the inlet port
32
to the outlet port
33
increases and the working oil amount flowing from the outlet port
33
to the discharge port
35
decreases. As a result, the pressure of the working oil discharged from the outlet port
33
increases.
In the electromagnetic valve
1
, electric current supplied into the coil
20
is controlled to adjust the force of the linear solenoid
10
pressing the spool
30
downwardly, and to adjust the pressure of the working oil discharge from the outlet port
33
. The pressure of the working oil discharged from the outlet port
33
decreases in proportion to the electric current supplied into the coil
20
. In this way, by controlling the electric current supplied into the coil
20
, position of the spool
30
is controlled to adjust the pressure of the working oil supplied into the automatic transmission.
A manufacturing process of the linear solenoid
10
will be explained with reference to FIG.
2
.
As shown in
FIG. 2A
, an accommodating base material
50
of the accommodating member
13
and an attracting base material
51
of the attracting member
14
are coaxially arranged, and are resin-insert-molded, thereby forming a bobbin base material
52
for the bobbin
52
.
Next, as shown in
FIG. 2B
, inner peripheries of the accommodating base material
50
, attracting base material
51
and bobbin base material
52
are cut from the opposite attracting base material
51
side to the attracting base material
51
side, so that the accommodating base material
50
, attracting base material
51
and bobbin base material
52
have same inner diameters.
As a result of the cut-forming process shown in
FIG. 2B
, the accommodating member
13
, the attracting member
14
and the bobbin
21
are formed as shown in FIG.
2
C.
Even when the accommodating base material
50
and the attracting base material
51
are coaxially insert-molded, axes thereof might be diverted from each other due to disposing errors of the accommodating base material
50
and the attracting base material
51
. However, in the present first embodiment, after insert-molding, the accommodating base material
50
, attracting base material
51
and bobbin base material
52
are cut to have the same inner diameters. Thus, the accommodating member
13
and the attracting member
14
are accurately coaxially formed. Since radial clearances between the plunger
17
and the accommodating member
13
, and between the plunger
17
and the attracting member
14
are made as small as possible, attracting force generated between the attracting member
14
and the plunger
17
becomes large relative to the electric current supplied into the coil
20
, thereby improving magnetic efficiency.
(Second Embodiment)
A manufacturing method of the linear solenoid in the second embodiment will be explained with reference to
FIGS. 3A-3C
.
As shown in
FIG. 3A
, an accommodating base material
50
and an attracting base material
51
are coaxially disposed, and are resin-insert-molded, thereby forming a bobbin base material
52
. The coil
20
is wound around the bobbin base material
52
.
Next, as shown in
FIG. 3B
, inner peripheries of the accommodating base material
50
, attracting base material
51
and bobbin base material
52
are cut from the opposite attracting base material
51
side to the attracting base material
51
side, so that the accommodating base material
50
, attracting base material
51
and bobbin base material
52
have same inner diameters.
As a result of the cut-forming process shown in
FIG. 3B
, the accommodating member
13
, the attracting member
14
and the bobbin
21
are formed as shown in FIG.
3
C.
In the second embodiment, the base material
50
, attracting base material
51
and bobbin base material
52
are cut after the coil
20
is wound around the bobbin base material
52
. Thus, in comparison with first embodiment in which the coil
20
is wound after the cut-forming process, force for winding the coil
20
does not act on the accommodating member
13
and the attracting member
14
. As a result, axes of the accommodating member
13
and the attracting member
14
are prevented from being diverted from each other.
(Third Embodiment)
FIG. 4
shows an electromagnetic valve in the third embodiment. A linear solenoid
60
works as an electromagnetic operating apparatus, and includes an accommodating member
62
, an attracting member
63
, and a thin thick portion
65
. The accommodating member
62
, the attracting member
63
, and the thin thick portion
65
are integrally formed to provide a stator core
61
. A cross-sectional area of the thin thick portion
65
is small, and the thin thick portion
65
works as a magnetic resistor for preventing magnetic flux from flowing between the accommodating member
62
and the attracting member
63
.
A manufacturing process of the linear solenoid
60
will be explained with reference to
FIGS. 5A-5C
.
As shown in
FIG. 5A
, a stator core base material
70
for the stator core
61
is resin-insert-molded, thereby forming a bobbin base material
71
for a bobbin
66
.
Next, as shown in
FIG. 5B
, inner periphery of the stator core base material
70
is cut from the accommodating member
62
side to the attracting member
63
side, so that the stator core base material
70
has a uniform inner diameter.
As a result of cut-forming process shown in
FIG. 5B
, the accommodating member
62
, attracting member
63
, thin thick portion
65
, and bobbin
66
are formed.
Since the accommodating member
62
is connected to the attracting member
63
through the thin thick portion
65
, surface for sliding with respect to the plunger
17
is formed of same material and with same roughness. Thus, the plunger
17
smoothly reciprocates in the accommodating member
62
and the attracting member
63
.
(Fourth Embodiment)
A manufacturing method of the linear solenoid in the fourth embodiment will be explained with reference to
FIGS. 6A-6C
.
As shown in
FIG. 6A
, the stator core base plate
70
is resin-insert-molded, thereby forming the bobbin base material
71
. The coil
20
is wound around the bobbin base material
71
.
Next, as shown in
FIG. 6B
, inner periphery of the stator core base material
70
is cut from the accommodating member
62
side to the attracting member
63
side, so that the stator core base material
70
has a uniform inner diameter.
As a result of cut-forming process shown in
FIG. 6B
, the accommodating member
62
, attracting member
63
, thin thick portion
65
, and bobbin
66
are formed.
In the fourth embodiment, the stator core base material
70
is cut after the coil
20
is wound around the bobbin base material
71
. Thus, in comparison with the third embodiment in which the coil
20
is wound after the cut-forming process, force for winding the coil
20
does not act on the stator core
61
. As a result, the stator core
61
is prevented from being transformed, thereby preventing axes of the accommodating member
62
and the attracting member
63
from being diverted from each other.
In the third and fourth embodiments, after the stator core base material
70
is cut to have the uniform inner diameter, the thin thick portion
65
is left for connecting the accommodating member
62
to the attracting member
63
. Alternatively, the stator core base material
70
may be cut to remove the thin thick portion for dividing the accommodating member
62
from the attracting member
63
.
(Fifth Embodiment)
FIG. 7
shows an electromagnetic valve
80
in the fifth embodiment. In the fifth embodiment, shapes of a yoke
81
and a stator core
82
are different from those in the third embodiment, and the stopper
15
is attached to the plunger
17
. The stator core
82
includes an accommodating member
83
, an attracting member
84
, and a thin thick portion
85
. The accommodating member
83
, attracting member
84
and thin thick portion
85
are integrally formed, and the thin thick portion
85
connects the accommodating member
83
to the attracting member
84
. Although shape of the stator core
82
is different from those in the third and fourth embodiments, the manufacturing processes of the stator core in the third and fourth embodiments may be used.
According to the above-described embodiments, since the accommodating member and the attracting member are accurately coaxially arranged, the radial clearances between the plunger
17
and the accommodating member, and between the plunger
17
and the attracting member are made as small as possible. Thus, the force attracting the plunger
17
is large relative to the electric current amount supplied into the coil
20
.
In the above-described embodiments, the electromagnetic operating apparatus in the present invention is used for an electromagnetic operating section of the spool type oil pressure control apparatus. Alternatively, the electromagnetic operating apparatus in the present invention may be used for other fluid control apparatuses.
Claims
- 1. A method for manufacturing an electromagnetic operating apparatus, said electromagnetic operating apparatus including:a moving core; an accommodating member for accommodating said moving core such that said moving core reciprocates therein; an attracting member disposed at one side of said accommodating member in a reciprocating direction of said moving core, said attracting member accommodating said moving core such that said moving core reciprocates therein, said attracting member forming a magnetic circuit with said moving core and said accommodating member; a coil provided outside said accommodating member and said attracting member, said coil generating a magnetic force attracting said moving core toward said attracting member when energized; and a bobbin made of resin and around which said coil is wound; the method for manufacturing said electromagnetic operating apparatus, comprising the steps of: resin-insert-molding an accommodating base material of said accommodating member and an attracting base material of said attracting member, which is independent from said accommodating member, for forming a bobbin base material of said bobbin; and processing the resin-insert-molded accommodating base material and attracting base material for forming said accommodating member and said attracting member to accommodate said moving core such that said moving core reciprocates therein, wherein said step of processing comprises changing a shape of said accommodating base material to define a shape of said accommodating member and changing a shape of said attracting base material to define a shape of said attracting member.
- 2. A method for manufacturing an electromagnetic operating apparatus according to claim 1, further comprising the steps of winding said coil around said bobbin base material after forming said bobbin base material and before processing the resin-insert-molded accommodating base material and attracting base material.
- 3. A method for manufacturing an electromagnetic operating apparatus, said electromagnetic operating apparatus including:a moving core; an accommodating member for accommodating said moving core such that said moving core reciprocates therein; an attracting member disposed at one side of said accommodating member in a reciprocating direction of said moving core, said attracting member accommodating said moving core such that said moving core reciprocates therein, said attracting member forming a magnetic circuit with said moving core and said accommodating member; a coil provided outside said accommodating member and said attracting member, said coil generating, a magnetic force attracting said moving core toward said attracting member when energized; and a bobbin made of resin and around which said coil is wound; the method for manufacturing said electromagnetic operating apparatus, comprising the steps of: resin-insert-molding a stator core base material, which includes base materials of said accommodating member and attracting member, and which includes a thin thick portion integrally formed to connect the base materials to each other, for forming a bobbin base material of said bobbin; and processing the resin-insert-molded stator core base material for forming a stator core to accommodate said moving core such that said moving core reciprocates therein, wherein said step of processing comprises changing a shape of said stator core base material to form a shape of said stator core.
- 4. A method for manufacturing an electromagnetic operating apparatus according to claim 3, wherein the processed thin thick portion connects said accommodating member to said attracting member.
- 5. A method for manufacturing an electromagnetic operating apparatus according to claim 3, further comprising the steps of winding said coil around said bobbin base material after forming said bobbin base material and before processing the resin-insert-molded stator core base material.
- 6. The method of manufacturing an electromagnetic operating apparatus according to claim 1, wherein the attracting member has a concavity which accommodates the moving core at least when the moving core is attracted toward the attracting member, the concavity being defined by a bottom surface axially facing the moving core and a cylindrical surface radially facing the moving core at least when the moving core is attracted, and wherein the processing step forms the concavity in the attracting base material.
- 7. The method for manufacturing an electromagnetic operating apparatus according to claim 6, wherein the attracting member further has a through hole coaxial with the concavity, the through hole being smaller in diameter than the concavity.
- 8. The method for manufacturing an electromagnetic operating apparatus according to claim 3, wherein the attracting member has a concavity which accommodates the moving core at least when the moving core is attracted toward the attracting member, the concavity being defined by a bottom surface axially facing the moving core and a cylindrical surface radially facing the moving core at least when the moving core is attracted, and wherein the processing step forms the concavity in the attracting base material.
- 9. The method for manufacturing an electromagnetic operating apparatus according to claim 8, wherein the attracting member further has a through hole coaxial with the concavity, the through hole being smaller in diameter than the concavity.
- 10. A method for manufacturing an electromagnetic operating apparatus according to claim 1, further comprising the step of winding said coil around said bobbin base material after forming said bobbin base material and after processing the resin-insert-molded accommodating base material and attracting base material.
- 11. A method for manufacturing an electromagnetic operating apparatus according to claim 1, wherein said step of processing comprises cuffing the resin-insert-molded accommodating base material and attracting base material to define a bore for accommodating the moving core.
- 12. A method for manufacturing an electromagnetic operating apparatus according to claim 3, further comprising the step of winding said coil around said bobbin base material after forming said bobbin base material and after processing the resin-insert-molded stator corn base material.
- 13. A method for manufacturing an electromagnetic operating apparatus according to claim 3, wherein said step of processing comprises cutting the resin-insert-molded stator core base material to define a bore for accommodating the moving core.
- 14. A method for manufacturing an electromagnetic operating apparatus according to claim 3, wherein said processing step includes removing the thin-thick portion to divide the accommodating member from the attracting member.
- 15. A method for manufacturing an electromagnetic operating apparatus according to claim 13, wherein said cutting step includes removing the thin-thick portion to divide the accommodating member from the attracting member.
Priority Claims (1)
Number |
Date |
Country |
Kind |
2000-209778 |
Jul 2000 |
JP |
|
US Referenced Citations (4)
Number |
Name |
Date |
Kind |
3331042 |
Erickson et al. |
Jul 1967 |
A |
3451021 |
Atherton |
Jun 1969 |
A |
3605054 |
Conrath |
Sep 1971 |
A |
5769391 |
Noller et al. |
Jun 1998 |
A |
Foreign Referenced Citations (1)
Number |
Date |
Country |
10-299932 |
Nov 1998 |
JP |