U.S. patent application number 10/911490 was filed with the patent office on 2005-01-20 for apparatus for controlling throttle valve and manufacturing method for the same and motor.
This patent application is currently assigned to DENSO CORPORATION. Invention is credited to Miura, Yuichiro.
Application Number | 20050011492 10/911490 |
Document ID | / |
Family ID | 27531804 |
Filed Date | 2005-01-20 |
United States Patent
Application |
20050011492 |
Kind Code |
A1 |
Miura, Yuichiro |
January 20, 2005 |
Apparatus for controlling throttle valve and manufacturing method
for the same and motor
Abstract
An apparatus for controlling a throttle valve has a body member
made of resin. The body member contains a motor for controlling a
throttle valve. The motor has a yoke as a one of components
thereof. The yoke is exposed to an intake passage at a slightly
upstream side of the throttle valve. According to the arrangement,
heat radiation from the motor is improved by intake airflow, and
the throttle valve can be prevented from an icing malfunction.
Inventors: |
Miura, Yuichiro; (Anjo-city,
JP) |
Correspondence
Address: |
NIXON & VANDERHYE, PC
1100 N GLEBE ROAD
8TH FLOOR
ARLINGTON
VA
22201-4714
US
|
Assignee: |
DENSO CORPORATION
|
Family ID: |
27531804 |
Appl. No.: |
10/911490 |
Filed: |
August 5, 2004 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10911490 |
Aug 5, 2004 |
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10062519 |
Feb 5, 2002 |
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6789526 |
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Current U.S.
Class: |
123/399 ; 310/24;
310/43 |
Current CPC
Class: |
F05C 2201/021 20130101;
F02D 9/104 20130101; F02M 15/02 20130101; F02D 9/1065 20130101;
Y02T 10/12 20130101; F02M 31/04 20130101; F02M 31/10 20130101; F02M
15/022 20130101; Y02T 10/126 20130101; F02D 11/10 20130101 |
Class at
Publication: |
123/399 ;
310/024; 310/043 |
International
Class: |
F02D 011/10 |
Foreign Application Data
Date |
Code |
Application Number |
Feb 8, 2001 |
JP |
2001-32911 |
Feb 9, 2001 |
JP |
2001-34481 |
Mar 27, 2001 |
JP |
2001-91002 |
Dec 20, 2001 |
JP |
2001-388056 |
Dec 20, 2001 |
JP |
2001-388220 |
Claims
1-13. (Canceled).
14. An apparatus for controlling a throttle valve for regulating an
amount of air flowing in an intake pipe of an internal combustion
engine, comprising: a body member made of a resin which has a
concavity for housing a motor component; and a bearing holder
member made of the same resin of the body member which is formed to
cover the concavity and supports a bearing member for supporting an
end of a rotation shaft of the motor component, wherein the bearing
holder member is fixed on the body member by a welding.
15. The apparatus for controlling the throttle valve according to
claim 14, wherein the motor component includes: a yoke fixed in the
concavity formed on the body member; a magnet attached on an inside
of the yoke; an armature having a rotation shaft which inserted
into an inside of the yoke where the magnet is attached; bearing
member which supports end of the rotation shaft, and is supported
on the body member; and bearing member which supports another end
of the rotation shaft, and is supported on the bearing holder
member.
16. The apparatus for controlling the throttle valve according to
claim 14, wherein a portion where the body member and the bearing
holder member are fixed by the welding is an inclined surface which
is arranged so that molten resin flows outside of the
concavity.
17. The apparatus for controlling the throttle valve according to
claim 14, wherein the body member provides a dam portion by an
extended part thereof, the dam portion being located on an inside
of a portion where the body member and the bearing holder member
are fixed by the welding, the dam portion damming molten resin.
18. The apparatus for controlling the throttle valve according
claim 14, wherein the body member and the bearing holder member
provides a positioning means by engaging portions thereof, the
positioning means being capable of aligning the rotation shaft and
the bearing member supported on the bearing holder member.
19. The apparatus for controlling the throttle valve according to
claim 14, wherein the bearing member supported on the bearing
holder member supports an output side or a counter-output side end
of the rotation shaft.
20. The motor apparatus, comprising: a body member made of a resin
having a concavity for housing a motor component; and a bearing
holder member fixed on the body member, which supports a bearing
member for supporting an end of a rotation shaft of the motor
component, wherein the body member and the bearing member are made
of the same resin, and the bearing holder member is fixed on the
body member by a welding.
21-24. (Canceled).
Description
CROSS REFERENCE TO RELATED APPLICATION
[0001] This application is based on Japanese Patent Applications
No. 2001-32911 filed on Feb. 8, 2001,No. 2001-34481 filed on Feb.
9, 2001, No. 2001-91002 filed on Mar. 27, 2001, No. 2001-388220
filed on Dec. 20, 2001, and No. 2001-388056 filed on Dec. 20, 2001,
the contents of which are incorporated herein by reference.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to an apparatus for
controlling a throttle valve, a method for manufacturing an
apparatus for controlling a throttle valve and a motor
apparatus.
[0004] 2. Description of Related Art
[0005] If the temperature is cold, the valve of the throttle valve
may get a malfunction by an icing. The icing is caused by moisture
in the air condensed within the intake pipe and froze on a contact
portion among a valve of the throttle valve and an inner wall of
the intake pipe.
[0006] JP-B-H07-49780 discloses an apparatus for controlling a
throttle valve for heating a vicinity of the valve by flowing an
engine coolant through a part of a throttle valve housing for
preventing it from getting cold. However, according to the
arrangement disclosed in the publication, a construction is complex
and also the cost may be expansive. Moreover, since the passage of
the engine coolant is only arranged on a very little part of a
portion of the throttle valve housing that is vicinity of the
valve, if the throttle valve housing is made of a low heat
conductive resin or the like, it may be difficult to prevent the
valve from the icing malfunction.
[0007] JP-A-H07-166897 discloses an apparatus for controlling a
throttle valve with a motor. The motor is directly provided in a
body member for the purpose of improving heat radiation and a
vibration resistance. A body member is formed of aluminum and the
like in order to reduce its weight and improve its heat radiation,
and a bearing holder member is attached to the body member by means
of such as screws or machine screws.
[0008] However, the above-described attachment of the motor housing
and the bearing holder member to the body member by means of the
screws or the machine screws undesirably causes the number of parts
and the number of assembly processes to be increased, which results
in a serious difficulty to decrease the manufacture cost of the
entire body of a throttle valve with a motor.
[0009] JP-A-H10-317998 discloses an apparatus for controlling a
throttle valve. The apparatus has a throttle body having a water
passage through which an engine coolant flows. However, the water
passage is only contact with a part of a circumference of an intake
air passage. Therefore it is difficult to heat the throttle valve
body sufficiently. Further, in case of the water passage being
formed in the throttle body, it is important to seal water in the
passage.
SUMMARY OF THE INVENTION
[0010] Therefore it is an object of the present invention to
provide an apparatus for controlling a throttle valve which is
capable of preventing the icing malfunction effectively.
[0011] It is another object of the present invention to provide a
motor apparatus which is capable of reducing number of parts and
manufacturing cost.
[0012] It is a further object of the present invention to improve
reliability of an apparatus for controlling a throttle valve made
of resin.
[0013] According to an aspect of the present invention, a yoke of a
motor for controlling a throttle valve is exposed to an intake air.
Therefore the motor is cooled and a valve is prevented from the
icing malfunction.
[0014] According to the other aspect of the present invention, a
passage through which a heat conductive medium flows is arranged to
pass through a vicinity of the motor. Therefore, the heat
conductive medium is heated by the motor and the valve is prevented
from the icing malfunction.
[0015] According to the other aspect of the present invention, a
bearing holder member and a body member are made of the same resin
and are welded. This arrangement makes it easy to manufacture and
reduces number of parts.
[0016] According to the other aspect of the present invention, the
body member is made of resin and has a passage in which a heat
conductive medium flows. In case of the above arrangement, bridge
portions are arranged in the passage to strengthen the body member.
In case of another arrangement, the body member is formed as a
seamless body to provide a reliable seal on the passage. In case of
still another arrangement, the body member provides pipes for an
intake and an outlet of the passages, which are formed by joining
separate parts. This arrangement provides reliable seal on the
passage.
BRIEF DESCRIPTION OF THE DRAWINGS
[0017] Features and advantages of embodiments will be appreciated,
as well as methods of operation and the function of the related
parts, from a study of the following detailed description, the
appended claims, and the drawings, all of which form a part of this
application. In the drawings:
[0018] FIG. 1 is a front view schematically showing an apparatus
for controlling a throttle valve with a motor according to a first
embodiment of the present invention;
[0019] FIG. 2 is a sectional view schematically showing the
apparatus taken along a section line II-II in FIG. 1;
[0020] FIG. 3 is a front view schematically showing an apparatus
for controlling a throttle valve with a motor according to a second
embodiment of the present invention;
[0021] FIG. 4 is a sectional view schematically showing the
apparatus taken along a section line IV-IV in FIG. 3;
[0022] FIG. 5 is a front view schematically showing an apparatus
for controlling a throttle valve with a motor according to a third
embodiment of the present invention;
[0023] FIG. 6 is a sectional view schematically showing the
apparatus taken along a section line VI-VI in FIG. 5;
[0024] FIG. 7 is a front view of an apparatus for controlling a
throttle valve with a motor according to a fourth embodiment of the
present invention;
[0025] FIG. 8 is a cross-sectional view schematically showing the
apparatus taken along a section line VIII-VIII in FIG. 7;
[0026] FIG. 9 is a sectional view schematically showing the entire
body of an apparatus for controlling a throttle valve with a motor
according to a fifth embodiment of the present invention;
[0027] FIG. 10 is an enlarged sectional view schematically showing
the motor shown in FIG. 9;
[0028] FIG. 11A shows the attached side surface of a bearing holder
member shown in FIG. 10;
[0029] FIG. 11B shows a side surface opposite to FIG. 11A, that is,
an outer side surface;
[0030] FIG. 12 is an enlarged sectional view schematically showing
a motor according to a sixth embodiment of the present
invention;
[0031] FIG. 13A shows the attached side surface of a bearing holder
member shown in FIG. 12;
[0032] FIG. 13B shows a side surface opposite to FIG. 13A, that is,
an outer side surface;
[0033] FIG. 14 is an enlarged sectional view schematically showing
a motor according to a seventh embodiment of the present
invention;
[0034] FIG. 15 is an enlarged sectional view schematically showing
a motor according to a eighth embodiment of the present
invention;
[0035] FIG. 16A shows the attached side surface of a bearing holder
member shown in FIG. 15;
[0036] FIG. 16B shows a side surface opposite to FIG. 16A, that is,
an outer side surface;
[0037] FIG. 17 is an enlarged sectional view schematically showing
a motor. according to a ninth embodiment of the present
invention;
[0038] FIG. 18 is a plane view of an apparatus for controlling a
throttle valve according to a tenth embodiment of the present
invention;
[0039] FIG. 19 is a sectional view on a sectional line XIX-XIX in
FIG. 18;
[0040] FIG. 20 is a sectional view of an apparatus for controlling
a throttle valve according to an eleventh embodiment of the present
invention;
[0041] FIG. 21 is a sectional view of an apparatus for controlling
a throttle valve according to a twelfth embodiment of the present
invention; and
[0042] FIG. 22 is a sectional view of an apparatus for controlling
a throttle valve according to a thirteenth embodiment of the
present invention.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
[0043] Herein after preferred embodiments of the present invention
will be described with reference to the drawings. In this
invention, an apparatus for controlling a throttle valve has a
motor for electrically control an opening degree of the throttle
valve or a mechanical link for manually control the opening degree
of the throttle valve.
[0044] In the drawings, the same or similar components are
designated by the same reference numerals, and the explanation will
not be repeated.
[0045] Referring to FIGS. 1 and 2, an apparatus for controlling a
throttle valve 1 has a throttle valve housing (body member) 10. The
throttle valve housing 10 has a part for forming a substantially
cylindrical intake pipe 11 in which a valve 12 of a throttle valve
is disposed, and a part for holding motor components such as a
substantially cylindrical yoke 14. The motor components supported
on the throttle valve housing 10 provide a motor 13. In this
embodiment, the throttle valve housing 10 has the above-described
two parts formed integrally and made of resin. In the intake pipe
11, a throttle valve shaft 15 for the valve 12 is provided to be
capable of rotating. The valve 12 opens and closes a passage in the
intake pipe 11 by its rotating movement. The motor 13 is disposed
in the throttle valve housing 10 with its rotation shaft parallel
to the throttle valve shaft 15. The output end of the motor 13 is
connected to power transmitting means 16 connected to the throttle
valve shaft 15. The output of the motor is transmitted to the valve
12 through the power transmitting means 16 to control the opening
degree. The opening degree of the throttle valve (opening degree of
the valve) is detected by a throttle position sensor 17 and used
for controlling the throttle valve.
[0046] In this embodiment, the motor 13 is arranged so that a part
of its yoke 14 is exposed to the intake pipe 11 in a slightly
upstream side of the valve 12 and the yoke 14 directly comes into
contact with a flow of air flowing in the intake pipe 11. The
exposed part is designed not to interfere with the rotating
operation of the valve 12 as shown by arrow marks in FIG. 2.
[0047] According to the above-described constitution, since the
flow of air in the intake pipe 11 directly comes into contact with
the yoke 14, the heat radiation of the motor 13 is accelerated and
the heat radiation of the motor is further improved without
requiring any additional member. Thus, the deterioration of the
torque of the motor due to the superheat of the motor is prevented.
Therefore, a compact motor whose torque is the smaller for a
conventionally expected deterioration of torque can be set and the
entire body of the apparatus is made compact.
[0048] Referring to FIGS. 3 and 4, in a second embodiment, an
apparatus 2 has a heat conductive member. Since the basic
constitution of the apparatus 2 is the same as that of the
apparatus 1 of the first embodiment, the same explanation will not
be repeated. In the apparatus 2, a heat conductive member 18 is
arranged to come into contact with a part of the yoke 14. The heat
conductive member 18 extends to an inside of the intake pipe 11 so
that the heat conductive member 18 comes into contact with the flow
of air flowing in the intake pipe 11. As shown in FIGS. 3 and 4,
the part of the heat conductive member 18 exposed to the intake
pipe 11 provides with protruding and concavities in order to
increase a heat radiation area and protrudes into the intake pipe
11. The part of the heat conductive member 18 protruding to the
intake pipe 11 is designed to be located in a slightly upstream
side of the valve 12 and not to interfere with the rotating
operation of the valve 12 as shown by arrow marks in FIG. 4.
Further, as apparent from FIG. 4, a part of the heat conductive
member 18 forms a part of the outer surface of the throttle valve
housing 10 and is also exposed to outside air. The heat conductive
member 18 is made of a member of high thermal conductivity such as
a metal.
[0049] According to such a constitution, heat generated in the
motor 13 is transferred to the heat conductive member 18. Since the
heat conductive member 18 is exposed to the intake pipe 11, a flow
of air in the intake pipe 11 comes into contact with the heat
conductive member 18 to promote the heat radiation of the motor.
13. According to this embodiment, since a part of the heat
conductive member 18 is also exposed to the outside air, the heat
of the motor is also radiated to the outside air. Therefore, a
better heat radiation is obtained.
[0050] In this embodiment, although the heat conductive member 18
is exposed to both of the intake pipe 11 and the outside air, the
heat conductive member 18 may be exposed to either of them.
Further, according to this embodiment, the protruding and
concavities for increasing the heat radiation area are formed only
on the part of the heat conductive member 18 exposed to the intake
pipe 11. However, similar protruding and concavities may be
provided on the part exposed to the outside air.
[0051] An apparatus 3 according to a third embodiment of the
present invention will be described below. Referring to FIGS. 5 and
6, a part of a yoke 14 is arranged so as to protrude and be exposed
to an intake pipe 11. Thus, the yoke 14 directly comes into contact
with the flow of air flowing in the inlet pipe. Further, in the
throttle valve with a motor 3, the heat conductive member 18 is
arranged to come into contact with a part of the yoke 14, and the
heat conductive member 18 extends to be exposed to the intake pipe
11 to come into contact with the flow of air flowing in the intake
pipe 11. According to this embodiment, although only the yoke 14
protrudes to the intake pipe 11, the part of the heat conductive
member 18 exposed to the intake pipe 11 may also protrude to the
intake pipe 11 similarly to the second embodiment. The part of the
yoke 14 protruding to the intake pipe 11 is designed to be located
in a slightly upstream side of a valve 12 and not to interfere with
the rotating operation of the valve 12. As apparent from FIG. 6, a
part of the heat conductive member 18 forms a part of the outer
surface of the throttle valve housing 10 and is also exposed to
outside air.
[0052] According to the above-described constitution, the same
effect is obtained as the first embodiment and the second
embodiment. Therefore, the heat radiation is improved compared with
those of other embodiments described above.
[0053] In the embodiment, although the heat conductive member 18 is
exposed to both the intake pipe 11 and the outside air, the heat
conductive member may be exposed to only one of them. Further, in
the embodiment, although protruding parts and concavities are not
especially formed on the parts of the heat conductive member 18
exposed to the intake pipe 11 and to the outside air, the
protruding parts and concavities for increasing the heat radiation
area as described in the second embodiment may be formed on both or
one of these parts.
[0054] Further, according to the above-described embodiments, one
or both of the portion of the yoke 14 exposed to the inside of the
intake pipe 11 and the portion of the heat conductive member 18
exposed to the inside of the intake pipe 11 is disposed to a
vicinity of the valve 12, as shown in the corresponding figures. By
arranging as described above, it is possible to prevent the valve
12 from the icing malfunction since the vicinity of the valve 12 is
heated by heat from the motor 13.
[0055] A fourth embodiment will be explained. Referring to FIGS. 7
and 8, the yoke 14 directly contacts with airflow in the intake
pipe since a part of the yoke 14 is disposed to protrude and expose
to the intake pipe 11. The portion of the yoke 14 protruding to the
intake pipe 11 is located on a slightly upstream side of the valve
12, and is constructed so as not to collide with a rotation of the
valve 12.
[0056] Especially for this embodiment, the ring-shaped hollow
portion, the ring passage 19, is arranged in the pipe wall that
construct the intake passage so as to surround the valve 12
disposed in the intake pipe 11 as shown in FIGS. 7 and 8. The ring
passage 19 is arranged so that a part thereof passes through a
vicinity of the motor 13 as shown in FIG. 8. A heat conductive
medium, e.g. an engine coolant, passes the ring passage 19
through.
[0057] By arranging as described above, in addition to the similar
advantage of helping heat dissipation by being directly contact the
yoke 14 with the air flow in the intake pipe 11, two advantages of
helping heat dissipation from the motor 13 and preventing the valve
12 from the icing malfunction are achieved by the heat conductive
medium flowing through the ring passage 19. That is, if the valve
may be frozen since the surroundings of the valve 12 is cold, e.g.
in case of low temperature, the surroundings of the valve is heated
by the heat conductive medium flowing in the ring passage 19.
Therefore the valve 12 is prevented from the icing malfunction. On
the other hand, if the temperature of the motor 13 rises, heat
dissipation from the motor is improved by transferring heat from
the motor 13 to the heat conductive medium, since the part of the
ring passage 19 is arranged to pass through the vicinity of the
motor 13. A temperature of the heat conductive medium flowing in
the ring passage 19 may be controlled so as to accomplish the
advantages.
[0058] Since the ring passage 19 is arranged to surround the valve
12 disposed within the intake pipe 11, it is possible to prevent
the valve from the icing malfunction reliably by heating an
entirety of surroundings of the valve 12 sufficiently, even if, for
example the throttle valve housing is made of a low heat conductive
resin or the like.
[0059] Although the engine coolant is utilized to pass through the
ring passage 19 in this embodiment, another heat conductive medium
such as another hot water or a heated air may be utilized.
[0060] Incidentally, although the throttle valve housing having the
above described ring shaped hollow portion (ring passage) 19 can be
manufactured by using the known several method. For example, it is
possible to obtain the above described ring passage 19 within the
throttle valve housing by composing the throttle valve housing by
two portions separated at a surface perpendicular to an axis of the
intake pipe 11 where the ring shaped hollow portion 19 is separated
into halves, and assembling them to match ring grooves formed on
respective portions. Further, a unitary and seamless throttle valve
housing may be provided by forming the hollow portion utilizing a
resin blow forming method or a lost-wax resin forming method using
a lost-wax type core or the like.
[0061] The arrangement of this embodiment may be combined with the
arrangement having the heat conductive member 18 described in the
description of the second and third embodiment, in case of that,
heat dissipation from the motor 13 is more improved.
[0062] As described above, the heat radiation of the motor is
improved by a simple and inexpensive means by a simple structural
change that does not need any additional members, and such as a
simple structural change and an additional heat conductive member.
Therefore, since it is possible to prevent the deterioration of
torque due to the superheat of the motor, the compact motor whose
torque is the smaller for the conventionally expected deterioration
of torque can be set. The entire body of the throttle valve with a
motor is made compact. Further, by using the similar means, on the
other hand, it is possible to prevent the valve from the icing
malfunction by using heat generated by the motor. Additionally, it
is possible to prevent the valve from the icing malfunction
reliably and to improve heat dissipation of the motor by arranging
the ring passage to surround the valve and flowing the heat
conductive medium therein.
[0063] In the above-described embodiments, although the motor is
disposed in the upstream side of the valve, it is to be understood
that similar effects may be obtained even when the motor is
disposed in a downstream side of the valve.
[0064] A fifth embodiment of an apparatus for controlling a
throttle valve will be described with reference to FIGS. 9, 10, 11A
and 11B. In an apparatus 113, a substantially cylindrical concavity
120 is provided in a part of a body member 110 for accommodating
the throttle valve 112 and forming a part of a motor housing. In
this embodiment, the body member 110 is made of resin. As shown in
FIG. 10, a cylindrical yoke 114 of which both ends are opened is
fixed to the inside surface of the concavity 120 provided in a part
of the body member 110. A magnet 121 is fixed to the inside surface
of the yoke 114.
[0065] In the concavity 120, a surface 110a inclined to be widened
outward is provided in the peripheral part of an opening part
thereof. In the outer peripheral side of the inclined surface 110a,
an attachment reference plane 110b substantially perpendicular to
the inside wall of the concavity 120 is further extended. Further,
in the outer peripheral side thereof, a positioning frame 122 as an
annular protruding part is provided. On the bottom part of the
concavity 120, a small concavity 123 is further formed and a
bearing 124 in a counter-output side is received in and attached to
the small concavity. An armature 126 having a rotation shaft 125 is
accommodated in the concavity 120 in which the yoke 114 and the
magnet 121 are installed. At this time, a part of the rotation
shaft 125 in the counter-output side is received and supported by
the bearing 124 in the counter-output side to be capable of
rotating.
[0066] On the other hand, a part of the rotation shaft 125 in an
output side is supported by a bearing 128 in the output side to be
capable of rotating. The bearing 128 in the output side is disposed
in a bearing holder member 127 attached so as to cover up the
concavity 120 in which the armature 126 is accommodated. The part
of the rotation shaft 125 in the output side passes through the
bearing holder member 127 as well as the bearing 128 in the output
side. The end part of the part of the rotation shaft 125 in the
output side provides with a motor gear 129 for connecting it to
power transmitting means in order to transmit the output of the
motor to the throttle valve 112.
[0067] FIGS. 11A and 11B respectively show the attached side
surface of the bearing holder member 127 (that is, a side surface
to be attached to the body member 12) and a side surface opposite
thereto (that is, an outer side surface). The bearing holder member
127 is substantially disk shaped and is made of the same resin as
that of the body member 110. As shown in FIG. 10, in this
embodiment, brushes 130 are attached to the bearing holder member
127. That is, the bearing holder member 127 serves as a brush
holder for holding the, brushes 130 at a proper position and
allowing the brushes 130 to assuredly come into contact with a
commutator 131. The bearing holder member 127 has a through hole
132 through which the rotation shaft 125 passes on its central
part.
[0068] In the periphery of the through hole 132 in the attached
side surface side, a concavity 133 is provided to receive the
bearing 128 in the output side. In the outermost peripheral part of
the attached side surface of the bearing holder member 127, an
annular positioning protrusion 134 is provided. The positioning
protrusion 134 has an outside surface 134a forming an alignment
reference surface of the bearing holder member 134, and a top
surface 134b forming an attachment height reference surface. In
other words, the outside surface 134a is engaged with the inside
surface 122a of the annular positioning frame 122. Further, the top
surface 134b abuts on the attachment reference plane 110b inwardly
adjacent to the positioning frame 122.
[0069] On the attached side surface of the bearing holder member
127, an annular welding protrusion 135 is provided so as to
correspond to the peripheral part of the opening of the concavity
120. More specifically, the outer side surface 135a of the welding
protrusion 135 is inclined so that its width becomes narrower as it
comes nearer to a top end of the protrusion 135. The inclined
surface 135a is located at a position corresponding to the inclined
surface 110a. Further, since a part of the welding protrusion 135
enters the concavity 120, the welding protrusion 135 is higher than
that of the positioning protrusion 134.
[0070] When the bearing holder member 127 is attached to the body
member 110, the inclined surface 135a of the welding protrusion 135
is welded to and stuck to the inclined surface 110a of the body
member 110 by a resin welding process. In the resin welding
process, both of the inclined surface 110a and 135a are melted and
then set continuously.
[0071] In the embodiment, since the body member 110 and the bearing
holder member 127 are made of the same resin material, they are
simply welded, stuck and fixed to each other by a resin welding
method. Further, the bearing holder member 127 is precisely
positioned in accordance with the above-described operations of the
positioning protrusion 134 and the positioning frame 122 and the
like.
[0072] The attachment of the bearing holder member 127 to the body
member 110 by the welding method can decrease the number of parts
and the number of assembly steps, compared with the attachment of a
bearing holder member to a body member by means of conventional
screws or bolts. The above-described constitution can contribute to
the decrease of the manufacture cost of the apparatus for
controlling the throttle valve with a built-in motor.
[0073] FIG. 12 shows a sixth embodiment of an apparatus 213. The
apparatus 213 is the same as the apparatus 113 shown in the first
embodiment except the constitution of a bearing holder member 227
and the constitution of a part of a body member 210.
[0074] An annular protrusion 240 is provided adjacently the
periphery of the opening of a concavity 220 provided in the body
member 210 in which an armature 126 is accommodated. A top surface
240a of the protrusion 240 forms an attachment reference plane. The
inside surface of the protrusion 240 forms a part of the inner side
surface of the concavity 220, and is substantially perpendicular to
the attachment reference plane.
[0075] As shown in FIG. 12, an outside surface 240b of the
protrusion 240 is inclined so that the lower part of the protrusion
240 is widened outward. In the outer part of the annular protrusion
240, an annular positioning frame 122 is further provided. An
annular groove 210a is formed between the protrusion 240 and the
positioning frame 122.
[0076] FIGS. 13A and 13B respectively show the attached side
surface of the bearing holder member 227 and a side surface
opposite thereto. The bearing holder member 227 is substantially
disk shaped, like the bearing holder member 127 of the first
embodiment. The bearing holder member 227 has the through hole 132
through which the rotation shaft 125 passes on its central part. In
the periphery of the through hole 132 in the attached side surface
side, the concavity 133 is provided to receive the bearing 128.
[0077] In the bearing holder member 227, an annular flat protrusion
244 is provided in the periphery adjacently the opening of the
concavity 133. The top surface 244a of the protrusion 244 forms the
attachment height reference surface of the bearing holder member
227. The inside surface of the protrusion 244 forms a part of the
inner side surface of the concavity 133. The protrusion 244 is
extended to a range that when the bearing holder member 227 is
attached to the body member 210, at least a part of the top surface
244a abuts on the top surface 240a of the protrusion 240 of the
body member 210. The top surface 240a abuts on the top surface 244a
so that a positioning operation in the direction of height (right
and left directions in FIG. 12) is carried out.
[0078] In the outermost peripheral part of the bearing holder
member 227, an annular positioning and welding protrusion 242 is
provided. The outside surface 242a of protrusion 242 is engaged
with the positioning frame 122 provided on the body member 210. The
engagement makes it possible to align the bearing holder member
227. On the other hand, the inside surface 242b of the protrusion
242 is inclined so as to correspond to the inclined surface 240b of
the body member 210. That is, while the bearing holder member 227
is attached to the body member 210, the protrusion 242 of the
bearing holder member 227 is fitted to the groove 210a.
[0079] When the bearing holder member 227 is attached to the body
member 210, the inclined surface 242b of the bearing holder member
227 is welded to and stuck to the inclined surface 240b of the body
member 210. In the embodiment, the body member 210 and the bearing
holder member 227 are made of the same resin material, and they are
simply welded, stuck and fixed to each other by a resin welding
method. Further, as mentioned above, the bearing holder member 227
is precisely positioned.
[0080] Further, in this embodiment, when the protrusion 240 abuts
on the protrusion 244 inward the welding part, and the output side
of the motor is disposed in an upper part (that is, when the
bearing holder member 227 side is disposed in the upper part), the
inclination of the welding part descends outward, so that molten
resin does not enter the concavity 220. In other words, there are
formed the welding part having the inclined surface 240a formed so
as to allow the molten resin to flow outward, and having molten
resin entry preventing means including the abutting part of a part
of the bearing holder member 227 and a part of the body member 210,
in which the part is located inward the welding part. In such a
manner, since the molten resin is prevented from entering the
motor, a manufacture is facilitated and the quality is improved due
to the deterioration of failure rate in a motor part.
[0081] FIG. 14 shows a seventh embodiment of an apparatus 313. The
apparatus 313 is substantially the same as the apparatus 213
disclosed in the sixth embodiment except for an arrangement of a
portion where a bearing holder member 327 and a body member 310 are
joined.
[0082] A ring like protrusion 340 and a ring like small protrusion
341 are located as shown in FIG. 14. The protrusion 340 is located
next to an opening of a concavity 320. The protrusion 340 surrounds
the opening. The small protrusion 341 is provided by extending a
portion of the body member 310 further from a top surface of the
protrusion 340. The small protrusion 341 provides a dam portion for
damming molten resin flow when the bearing holder member 327 is
welded on the body member 310. The protrusion 340 corresponds to
the protrusion 240 in the sixth embodiment.
[0083] The arrangement and the functions of the parts of the
bearing holder 327 in this embodiment are substantially the same as
those of the sixth embodiment. Therefore, the explanation will not
be repeated.
[0084] In this embodiment, a top surface of the ring shaped
protrusion 344 is arranged to be not contact with a top surface of
the protrusion 340 of the body member 310 as shown in FIG. 12.
[0085] Attaching the bearing holder member 327 to the body member
310 is performed by welding inclined surfaces on the protrusions
242 and 340. It is possible to fix them easily by the welding
process since the body member 310 and the bearing holder member 327
are made of the same resin in this embodiment too. Also, it is
possible to fix the bearing holder member 327 with an accurate
positioning.
[0086] A dam for damming molten resin that flows out from the
portions for fixing the body member 310 and the bearing holder
member 327 when the welding process is carried out is provided.
Thereby, it is possible to ease the manufacturing and to improve a
quality such as a reducing failure rate of the motor.
[0087] Although the embodiment employs both of the arrangements,
the inclined surfaces and the dam, it is possible to employ only
one of those arrangements as a means for preventing a leak of the
molten resin.
[0088] FIG. 15 shows an eighth embodiment of an apparatus. The
apparatus 413 has a bearing holder member 427 on a counter-output
side. The bearing 128 in the output side is directly attached to a
body member 410 and the bearing 124 in the counter-output side is
attached to a bearing holder member 427 which is welded, stuck and
fixed to the body member 410.
[0089] A substantially cylindrical concavity 420 is provided in the
body member 410. In this embodiment, the body member 410 and the
baring holder member 427 are made of the same resin.
[0090] A inclined surface 410a to be widened outward is provided in
the peripheral part of an opening of the concavity 420. An
attachment reference plane 410b substantially perpendicular to the
inside wall of the concavity 420 is further extended. Further, in
the outer peripheral side thereof, a positioning frame 422 as an
annular protruding part is provided.
[0091] On the bottom part of the concavity 420, a hole 432 through
which the output side of the rotation shaft 125 passes is provided
at its center, a small concavity 433 is formed in the periphery of
the through hole 432 and the bearing 128 is received in and
attached to the concavity 433. Further, the brushes 130 are
attached to the bottom part of the concavity 420. The brushes 130
are held at a suitable position to allow the brushes to assuredly
come into contact with a commutator 131. The armature 126 having
the rotation shaft 125 is accommodated in the concavity 420 in
which the yoke 114 and the magnet 121 are installed. At this time,
the output side part of the rotation shaft 125 passes through the
bearing 128 and is supported to be capable of rotating and passes
through the through hole 432. The motor gear 129 is attached on the
end of the rotation shaft 125.
[0092] On the other hand, the counter-output side part of the
rotation shaft is supported by the bearing 124 to be capable of
rotating. The bearing 124 is disposed in the bearing holder member
427 attached so as to cover up the concavity 420.
[0093] FIGS. 16A and 16B respectively show the attached side
surface of the bearing holder member 427 and a side surface
opposite thereto. The bearing holder member 427 is substantially
disk shaped and is made of the same resin as that of the body
member 410. In this embodiment, the bearing holder member 427 has a
concavity 423 provided at the central part of the attached side
surface to receive the bearing 124. In the outermost peripheral
part of the attached side surface of the bearing holder member 427,
an annular positioning protrusion 434 is provided. The positioning
protrusion 434 has outside surface 434a forming an alignment
reference surface of the bearing holder member 427 and top surface
434b forming an attachment height reference surface. The outside
surface 434a engages with the inside surface of the annular
positioning frame 422 provided around the opening part of the
concavity 420 to align the bearing holder member 427. Therefore, an
alignment between the rotation shaft 125 and the counter-output
side bearing 124 supported on the bearing holder member 427 is
carried out. Further, the top surface 434b (that is, a surface
facing the body member 410 to which the positioning protrusion is
attached) abuts on an attachment reference plane 410b inwardly
adjacent to the positioning frame 422 to position the bearing
holder member 427 in the direction of height.
[0094] An annular welding protrusion 435 is provided so as to
correspond to the peripheral part of the opening part of the
concavity 420. More specifically, the welding protrusion 435 has
its outside surface 435a inclined so that its width becomes
narrower as it comes nearer to the end of the protrusion 435. The
inclined surface 435a is located at a position corresponding to the
inclined surface 410a. Further, since a part of the welding
protrusion 435 enters the opening part of the concavity 420, the
height of the welding protrusion 435 is higher than that of the
positioning protrusion 434.
[0095] When the bearing holder member 427 is attached to the body
member 410, the inclined surfaces 410a and 435a are welded. The
means for preventing the concavity form entering the molten resin
may be also applied to the eighth embodiment.
[0096] A ninth embodiment of an apparatus 513 is shown in FIG. 17.
The apparatus 513 of the embodiment is the same in an aspect that
the motor components are housed in a concavity 520 that is
substantially cylindrical and is formed in a body member 510.
However, the embodiment employs an arrangement in which a motor
housing 550 houses the other motor components and is housed in the
concavity 520 as shown in FIG. 17.
[0097] In detail, the motor housing 550 is cup-shaped and performs
to assemble the motor components on predetermined positions therein
and to support the motor components integrally. The yoke 114 is
fixed on an inside surface of the motor housing 550, and the magnet
121 is fixed on an inside surface of the yoke 114. The
counter-output side bearing 124 is housed and fixed in a small
concavity 551 formed on a bottom of the motor housing 550. The
armature 126 having the rotation shaft 125 is housed in an inner
space 552 of the motor housing 550 where the yoke 114 and the
magnet 121 are disposed.
[0098] When the armature 126 is housed in the motor housing 550, a
counter-output side end of the rotation shaft 125 is received and
supported by the counter-output side bearing 124. The output side
bearing 128 disposed in the bearing holder member 527 rotatably
supports an output side end of the rotation shaft 125. The bearing
holder member 527 is attached on the cup-shaped motor housing 550
with the armature 126 so as to cover the motor housing 550. The
output side end of the rotation shaft 125 is disposed to pass
through the output side bearing 128 and the bearing holder member
527, and a motor gear 129 for linking with a power transmitting
means and transferring an output of the motor to the throttle valve
is attached on a distal end thereof.
[0099] A surface 510a inclined to enlarge toward radial outside is
formed on a radial outside of an opening of the concavity 520. An
assembling reference plane surface 510b which is substantially
perpendicular to an inside wall of the concavity 520 is formed and
extended on a radial outside of the inclined surface 510a. A
positioning frame 122, which is a ring shaped protrusion, is
disposed on a radial outside of the assembling reference plane
surface 510b. The body member 510 is also made of resin in this
embodiment.
[0100] The arrangement and the functions of the parts of the
bearing holder 527 in this embodiment are substantially the same as
those of the bearing holder member 127 of the first embodiment.
Therefore, the explanation will not be repeated. However, in this
embodiment, differently from the case of the first embodiment, the
motor housing 550 is attached on the end surface of the welding
protrusion 535 as shown in FIG. 17. During an assemble of the
apparatus 513, first the motor housing 550 housing the component of
the motor is attached on the bearing holder member 527, then the
bearing holder member 527 is attached on the body member 510 so
that the motor housing 550 is housed in the concavity 520.
[0101] Attaching the bearing holder member 527 to the body member
510 is performed by a resin welding process as well as the first
embodiment.
[0102] As described above, according to the embodiments, the
apparatus for controlling the throttle valve, especially a motor
apparatus, is assembled by welding the bearing holder member to the
body member. Therefore, the number of parts and the number of
assembling steps are decreased compared with the conventional case
in which the small machine screws or bolts are used, which can
contribute to the decrease of the manufacture cost.
[0103] The bearing holder member and the body member may be made of
material such as PBT (Polybutylene terephthalate) and PPS
(Polyphenylene sulfide) which are categorized in a thermoplastic
engineering resin.
[0104] The welding between the bearing holder member and the body
member may be carried out by methods such as a laser welding, an
ultrasonic welding and a vibrating welding.
[0105] Although the embodiments are the throttle valve, that is the
apparatus for controlling the throttle valve, the present invention
may be implemented on a motor apparatus for other purposes.
Although the examples of a DC motor are given, equivalent effects
may be obtained by other motors such as a step motor.
[0106] A tenth embodiment of an apparatus for controlling a
throttle valve will be explained. In this embodiment, the apparatus
for controlling the throttle valve provides manual operations and
controls of the throttle valve. FIGS. 18 and 19 shows an apparatus
for controlling a throttle valve of a tenth embodiment.
[0107] An apparatus 600 has a valve housing 610 forming an intake
passage 602, a valve shaft 615 supported in the valve housing 610
to be capable of freely rotating, a valve 612 fixed to the valve
shaft 615 to vary the opening area of the intake passage 602, a
transmitting member 616 for transmitting a turning force to the
valve shaft 615 and a turning angle sensor 617 for detecting the
turning angle of the valve shaft 615. As shown in FIG. 19, the
apparatus 600 is arranged, when it is mounted on a vehicle, so that
its intake upstream side communicates with an intake air duct
having an air filter 604 in an airtight manner, and so that its
intake downstream side communicates with an internal combustion
engine 608 having an intake manifold in an airtight manner.
[0108] The valve housing 610 is made of a resin material and forms
a substantially cylindrical intake pipe as shown in FIGS, 18 and
19. The valve housing 610 has the intake passage 602 in the air
intake pipe.
[0109] As shown in FIG. 19, the valve housing 610 includes an outer
peripheral wall part 611 forming the intake passage 602 therein,
and bearing parts 663 and 664 for supporting both end portions 661
and 662 of the valve shaft 615 to be capable of freely rotating.
The outer peripheral wall part 611 has a predetermined thickness so
as to form a circular section of the air intake passage as shown in
FIG. 19. The bearing parts 663 and 664 are formed in substantially
cylindrical forms (see FIG. 19), and their inner parts directly
bear both end portions 661 and 662 so that the valve shaft 615 is
capable of freely rotating. The bearing parts 663 and 664 provide
bridge portions to connect an inner wall and an outer wall of the
wall 611.
[0110] The detail of the structures and functions of the valve
housing 610, specially, the outer peripheral wall part 611 and the
bearing parts 663 and 664 which are the main parts will be
described below.
[0111] The valve shaft 615 is formed in a substantially cylindrical
shape and is supported by both of the bearing parts 663 and 664 to
be capable of freely rotating. One end portion 661 of the valve
shaft 615 is accommodated in the bearing part 663. The other end
portion 662 passes through the bearing part 664 and an external
force for externally rotating the valve shaft 615 is exerted
thereon. The lever 616 is engaged with an accelerator pedal (not
shown) on vehicle through an accelerator wire (not shown).
[0112] The external force exerted on the valve shaft 615 is not
limited to a mechanical external force interlocking with the
movement of the accelerator pedal through the lever 616. An
electrical external force by a driving motor for driving the valve
shaft 615 so as to freely rotate may be employed.
[0113] The valve 612 is fixed to the valve shaft 615 so as to make
the opening area of the intake passage 602 variable and disposed in
the intake passage 602 to be capable of rotating together with the
valve shaft 615.
[0114] As shown in FIG. 19, when the turning angle of the valve
shaft 615 is located at a completely closed position, that is, when
the valve 612 is located at its completely closing position, the
valve 612 is held at a position shown by a solid line. The valve
612 makes the opening area of the air intake passage 10a none, that
is, the valve body makes the intake passage 602 (specifically, a
cross-section) close. Further, when the valve 612 is located at its
completely opening position, the valve 612 is held at a position
shown by a two-dot chain line so as to completely open the opening
area of the intake passage 602, that is, held substantially
perpendicularly to the cross-section of the intake passage 602.
[0115] Therefore, since the valve 612 is ordinarily freely or
movably fitted to the intake passage 602 within a range in the
vicinity of a position where the turning angle of the valve shaft
615 is located at its completed closed position. Especially at the
completely closing position, the valve 612 is fitted to the intake
passage 602 so as to close the intake passage 602. Therefore,
so-called icing is susceptible to occurring, since the valve 612 or
the valve shaft 615 is apt to be frozen with the valve hosing 610
due to vapor condensation caused by leaving the device in a low
temperature environment. The structural features of the present
invention for preventing the icing state will be described
hereinafter.
[0116] The turning angle sensor 617 detects the turning angle of
the valve shaft 615, and is a known sliding resistor for varying a
resistance value in accordance with the turning angle of the valve
shaft 615.
[0117] There will be described below the structural feature for
heating the valve housing 610, particularly the outer peripheral
wall part 611 forming the intake passage 602 and the bearing parts
663 and 664 for rotatably supporting the valve shaft 615 which are
the main parts.
[0118] As shown in FIGS. 18 and 19, in the outer peripheral wall
part 611, a hollow part 665 having an annular space formed between
the inner peripheral wall 666, outer peripheral wall 667 and both
axial end walls. The bearing parts 663 and 664 bridges both of the
peripheral walls.
[0119] More specifically, the inner peripheral wall 666 defines the
intake passage 602. The bearing parts 663 and 664 are fixed in an
airtight manner between the peripheral walls so as to bridge over
them. Therefore, the hollow part 665 is formed in a substantially
annular form to surround the intake passage 602 at a radial outside
of the valve 612.
[0120] The outer peripheral wall 667 has connecting pipes 668 and
669 for introducing and discharging a heat conductive medium, such
as hot water. As shown in FIGS. 18 and 19, the connecting pipes 668
and 669 are respectively connected to pipe 670 made of rubber in an
airtight manner. The pipes 670 provide with clamps 671 as
dislocation preventing means.
[0121] The heat conductive medium may be fluid capable of
circulating and being introduced to and discharged from the space R
and may be either liquid or gas. In the embodiments of the present
invention, the heat conductive medium will be described as the hot
water, hereinafter.
[0122] The hot water enters the annular hollow part 665 from the
connecting pipe 668 in the direction shown by an arrow mark in FIG.
18, flows along the inner peripheral wall 666. The hot water
especially flows on the outer periphery of the wall 666 and the
outer peripheries of the bearing portions 663 and 664, and then
flows out from the connecting pipe 669.
[0123] Thus, the hot water passes through the annular hollow part
665, so that the hollow part 665 can form a heat conductive medium
passage (refer it to as a hot water passage, hereinafter). Since
the airtight hollow part 665 is formed in the valve housing 610
made of a resin material, the capacity of the hot water passage 665
is increased depending on the size. Therefore, since the apparatus
can increase the capacity of the hot water passage, a heating
capability for preventing frost is improved.
[0124] In addition, since the hot water introduced to the hollow
part 665 can directly heat the wall 666 defining the intake passage
602 and the bearing portions 663 and 664, the wall 666, the valve
612 and the valve shaft 615 are assuredly prevented from being
frozen.
[0125] As a method for producing the valve housing 610 made of the
resin material, the hollow part 665 may be formed by employing a
resin blow molding method, a resin molding method by using a
lost-wax type core and the like. In case of using the resin blow
molding method or the resin molding method by the lost-wax core, it
is possible to provide a seamless type valve housing 610 can be
integrally formed. In this case, at least one of the pipes 668 and
669 may be used as an opening to introduce a pressurized air in the
resin blow molding method or to support the core in a molding
cavity.
[0126] Thus, reliability of the air-tightness such as an anti-air
leakage is improved in comparison with a conventional arrangement
which uses airtight members such as seal gaskets.
[0127] FIG. 20 shows a eleventh embodiment of an apparatus for
controlling a throttle valve. In this embodiment, an insert core
673 is added to the inner peripheral wall 666.
[0128] As shown in FIG. 20, the insert core 673 made of annular
metal is provided in the vicinity of the completely closing
position of the valve 612. Accordingly, the insert core 673 made of
a metal material having a thermal conductivity higher than that of
the resin material can be disposed so that a heating capability is
improved.
[0129] Since the insert core 673 is arranged within a range in the
vicinity of a position where the valve 612 is completely closed,
that is, within a range in which the valve 612 is freely or movably
fitted to an intake passage 602 or fitted to the intake passage, a
frost prevention is assuredly implemented.
[0130] A method for providing the insert core 673 in a valve
housing 610 is not limited to a method for casting the insert core
673 when the valve housing 610 is subjected to a resin molding
method. A method may be employed for dividing the valve housing
610, performing the resin molding method for the valve housing, and
then holding the insert core 673 between the divided valve housing
parts as in an embodiment described below.
[0131] FIG. 21 shows a twelfth embodiment of an apparatus for
controlling a throttle valve. In this embodiment, the valve housing
610 is made of two parts. The hollow part 665 is formed by grooves
formed on the parts respectively.
[0132] As shown in FIG. 21, the valve housing 610 is axially
divided into a first housing 680 and a second housing 690 along an
axis of the intake passage, and made of a resin material upon resin
molding. The first housing 680 has a wall part 681 and bearing
parts 682 and 683. The second housing 690 has a wall part 691 and
bearing parts 692 and 693. The wall parts 681 and 691 form the wall
portion 611 that defines the intake passage 602 and the annular
hollow part 665 therein. The first housing 680 is joined to the
second housing 690 by employing a vibration weld sticking method
and the like.
[0133] As shown in FIG. 21, connecting parts 684 and 685 are
provided on the first housing 680 for introducing hot water to or
discharging it from the hollow part 665. The connecting parts 684
and 685 may be provided in either the first housing 680 or the
second housing 690.
[0134] Accordingly, the capacity of the hot water circulating
passage of the hollow part 15 is increased in accordance with the
size of an interior space of the hollow part 665. A heating
capability for frost prevention is improved. The hot water
introduced to the hollow part 665 can directly heat the wall 666
defining the intake passage 602, and the bearing parts 682, 683,
692 and 693. The intake passage 602, the valve 612 and the valve
shaft 615 are assuredly prevented from being frozen.
[0135] Further, the valve housing 610 is divided, and the divided
valve housings are formed of a resin material. The valve housing
610 subjected to a resin molding method, that is, the die designs
of the first housing 680 and the second housing 690 is designed
more easily, compared with an integral resin molding work by using
a blow molding method and the like. Therefore, a manufacture cost
for the resin molding such as the cost of the dies is reduced.
Consequently, the inexpensive apparatus for controlling the
throttle valve can be provided.
[0136] As shown in FIG. 21, the insert core 673 may be sandwiched
between the first housing 680 and the second housing 690. Thus, the
insert core 673 made of metal having a thermal conductivity higher
than that of the resin material can be provided as in the above
embodiments. In addition, since the insert core 673 is arranged
within a range in the vicinity of a position where the valve 612 is
completely closed, that is, within a range in which the valve 612
is freely or movably fitted or fitted to the intake passage 602,
frost prevention is assuredly attained.
[0137] FIG. 22 shows a thirteenth embodiment of an apparatus for
controlling a throttle valve. In this embodiment, one of the
connecting pipes is formed by a part 686 integrally formed on the
first housing 680 and a part 696 integrally formed on the second
housing 690. In the same manner, another one of the connecting
pipes is formed by a part 687 integrally formed on the first
housing 680 and a part 697 integrally formed on the second housing
690.
[0138] Accordingly, the connecting pipes may provide with bulges
676 and 677 for preventing the dislocation of pipes 670 by taking
the designs of dies into consideration.
[0139] The dislocation of the pipes 670 is assuredly prevented, so
that the lowering of reliability in the air-tightness such as an
air leakage is surely prevented.
[0140] Although the present invention has been described in
connection with the preferred embodiments thereof with reference to
the accompanying drawings, it is to be noted that various changes
and modifications will be apparent to those skilled in the art.
Such changes and modifications are to be understood as being
included within the scope of the present invention as defined in
the appended claims.
* * * * *