U.S. patent application number 16/123647 was filed with the patent office on 2019-03-21 for mounting structure, rotational machinery, air conditioning apparatus, and adjustment method.
This patent application is currently assigned to Kabushiki Kaisha Toshiba. The applicant listed for this patent is Kabushiki Kaisha Toshiba. Invention is credited to Takayuki MASUNAGA, Shanying PAN, Misuzu SAKAI.
Application Number | 20190085860 16/123647 |
Document ID | / |
Family ID | 65720054 |
Filed Date | 2019-03-21 |
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United States Patent
Application |
20190085860 |
Kind Code |
A1 |
SAKAI; Misuzu ; et
al. |
March 21, 2019 |
MOUNTING STRUCTURE, ROTATIONAL MACHINERY, AIR CONDITIONING
APPARATUS, AND ADJUSTMENT METHOD
Abstract
According to one embodiment, a mounting structure includes: a
first member including a first outer surface provided with first
dents arranged around a second axis at an interval of a first
angular distance; a second member including a second inner surface
provided with second dents arranged around the second axis at an
interval of a second angular distance, and a second outer surface
provided with third dents arranged around a third axis at an
interval of a third angular distance; a third member includes a
third inner surface provided with fourth dents arranged around the
third axis at an interval of a fourth angular distance; a first
limiting member housed in one of the first dents and one of the
second dents opposing each other; and a second limiting member
housed in one of the third dents and one of the fourth dents
opposing each other.
Inventors: |
SAKAI; Misuzu; (Yokohama,
JP) ; MASUNAGA; Takayuki; (Yokohama, JP) ;
PAN; Shanying; (Chigasaki, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Kabushiki Kaisha Toshiba |
Minato-ku |
|
JP |
|
|
Assignee: |
Kabushiki Kaisha Toshiba
Minato-ku
JP
|
Family ID: |
65720054 |
Appl. No.: |
16/123647 |
Filed: |
September 6, 2018 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
F04D 29/662 20130101;
F04D 29/281 20130101; F04D 29/263 20130101; F04D 29/668 20130101;
F04D 25/08 20130101 |
International
Class: |
F04D 29/26 20060101
F04D029/26; F04D 29/28 20060101 F04D029/28; F04D 29/66 20060101
F04D029/66 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 15, 2017 |
JP |
2017-178343 |
Claims
1. A mounting structure, comprising: a first member including: a
first inner surface that extends along and around a first axis, at
least a part of the first inner surface which forms a first hole;
and a first outer surface that is opposite the first inner surface,
extends along and around a second axis different from the first
axis, and is provided with one or more first dents arranged around
the second axis at an interval of a first angular distance; a
second member including: a second inner surface that extends along
and around the second axis and is provided with one or more second
dents arranged around the second axis at an interval of a second
angular distance different from the first angular distance, at
least a part of the second inner surface which forms a second hole
that allows the first member to be housed, in contact with the
first outer surface of the first member; and a second outer surface
that is opposite the second inner surface, extends along and around
a third axis different from the second axis, and is provided with
one or more third dents arranged around the third axis at an
interval of a third angular distance; a third member including: a
third inner surface that extends along and around the third axis
and is provided with one or more fourth dents arranged around the
third axis at an interval of a fourth angular distance different
from the third angular distance, at least a part of the third inner
surface which forms a third hole that allows the second member to
be housed, in contact with the second outer surface of the second
member; a first limiting member that is housed in one of the one or
more first dents and one of the one or more second dents opposing
each other, and limits rotation of the first member and the second
member around the second axis; and a second limiting member that is
housed in one of the one or more third dents and one of the one or
more fourth dents opposing each other, and limits rotation of the
second member and the third member around the third axis.
2. The mounting structure according to claim 1, wherein the first
axis, the second axis, and the third axis are in parallel with one
another, and a distance between the first axis and the second axis
is equal to a distance between the second axis and the third
axis.
3. The mounting structure according to claim 2, wherein a first
difference between the third angular distance and the fourth
angular distance is a divisor of at least one of the third angular
distance and the fourth angular distance.
4. The mounting structure according to claim 3, wherein at least
one of the third angular distance and the fourth angular distance
is set to a divisor of 360-degree angle.
5. The mounting structure according to claim 4, wherein a first
angle .theta..sub.1 being one of the third angular distance and the
fourth angular distance is equally divided into n.sub.1 parts by a
difference .DELTA..theta..sub.12 between the first angle
.theta..sub.1 and a second angle .theta..sub.2 being the other of
the third angular distance and the fourth angular distance, a
360-degree angle is equally divided into n.sub.2 parts by the first
angle .theta..sub.1, when the difference .DELTA..theta..sub.12 is a
divisor of 360-degree angle, a combination of the first angle
.theta..sub.1 and the second angle .theta..sub.2 satisfies the
following first expression: ( n 1 - 1 ) 2 n 1 - n 2 < 0 ( if
.theta. 1 > .theta. 2 ) n 1 2 - 1 n 1 - n 2 < 0 ( if .theta.
1 < .theta. 2 ) First expression ##EQU00004## and the
combination results in a value closest to zero from the first
expression among multiple combinations of the first angle
.theta..sub.1 and the second angle .theta..sub.2, and when the
difference .DELTA..theta..sub.12 differs from a divisor of
360-degree angle, the combination of the first angle .theta..sub.1
and the second angle .theta..sub.2 satisfies the following second
expression:
(.theta..sub.1-.DELTA..theta..sub.12).sup.2-180.degree..DELTA..theta..sub-
.12<0 (if .theta..sub.1>.theta..sub.2)
.theta..sub.1.sup.2-.DELTA..theta..sub.12.sup.2-180.degree..DELTA..theta.-
.sub.12<0 (if .theta..sub.1<.theta..sub.2) Second expression
and the combination results in a value closest to zero from the
second expression among multiple combinations of the first angle
.theta..sub.1 and the second angle .theta..sub.2.
6. The mounting structure according to claim 2, wherein a second
difference between the first angular distance and the second
angular distance is a divisor of at least one of the first angular
distance and the second angular distance.
7. The mounting structure according to claim 6, wherein at least
one of the first angular distance and the second angular distance
is set to a divisor of 360-degree angle.
8. The mounting structure according to claim 7, wherein a third
angle .theta..sub.3 being one of the first angular distance and the
second angular distance is equally divided into n.sub.3 parts by a
difference .DELTA..theta..sub.34 between the third angle
.theta..sub.3 and a fourth angle .theta..sub.4 being the other of
the first angular distance and the second angular distance, a
360-degree angle is equally divided into 1/2n.sub.4 parts by the
third angle .theta..sub.3, when the difference
.DELTA..theta..sub.34 is a divisor of 360-degree angle and the
number of the one or more first dents or the one or more second
dents arranged around the second axis at an interval of the fourth
angle .theta..sub.4 is N, a combination of the third angle
.theta..sub.3 and the fourth angle .theta..sub.4 satisfies the
following third and fourth expressions: ( n 3 - 1 ) 2 n 3 - 2 n 4
< 0 ( if .theta. 3 > .theta. 4 ) n 3 2 - 1 n 3 - 2 n 4 < 0
( if .theta. 3 < .theta. 4 ) Third expression 180 .degree.
.DELTA. .theta. 34 .ltoreq. n 4 ( N - 1 ) ( if .theta. 4 is not a
divisor of 720 ) 180 .degree. .DELTA. .theta. 34 .ltoreq. n 4 N (
if .theta. 4 is a divisor of 720 ) Fourth expression ##EQU00005##
and the combination results in a value closest to zero from the
third expression among multiple combinations of the third angle
.theta..sub.3 and the fourth angle .theta..sub.4, and when the
difference .DELTA..theta..sub.34 differs from a divisor of
360-degree angle, the combination of the third angle .theta..sub.3
and the fourth angle .theta..sub.4 satisfies the following fifth
expression:
(.theta..sub.3-.DELTA..theta..sub.34).sup.2-180.degree..DELTA..theta..sub-
.34<0 (if .theta..sub.3>.theta..sub.4)
.theta..sub.3.sup.2-.DELTA..theta..sub.34.sup.2-180.degree..DELTA..theta.-
.sub.34<0 (if .theta..sub.3<.theta..sub.4) Fifth expression
and the combination results in a value closest to zero from the
fifth expression among multiple combinations of the third angle
.theta..sub.3 and the fourth angle .theta..sub.4.
9. The mounting structure according to claim 7, wherein a
difference .DELTA..theta..sub.34 between the third angle
.theta..sub.3 being one of the first angular distance and the
second angular distance and the fourth angle .theta..sub.4 being
the other of the first angular distance and the second angular
distance is a divisor of the third angle .theta..sub.3, the third
angle .theta..sub.3 is a divisor of 360-degree angle, the
difference .DELTA..theta..sub.4 is a divisor of 360-degree angle,
and when a value obtained by dividing a 360-degree angle by the
difference .DELTA..theta..sub.34 is an odd number, the third angle
.theta..sub.3 and the difference .DELTA..theta..sub.34 satisfy the
following sixth expression: .theta..sub.3=2.DELTA..theta..sub.34
Sixth expression and the number of the one or more first dents or
the one or more second dents arranged at an interval of the fourth
angle .theta..sub.4 is one.
10. Rotational machinery, comprising: the mounting structure
according to claim 1; and a power source that includes a shaft to
be inserted into the first hole, to rotate the shaft.
11. An air conditioning apparatus, comprising: the mounting
structure according to claim 1; a power source that includes a
shaft to be inserted into the first hole, to rotate the shaft; and
a fan connected to the third member.
12. An adjustment method of a mounting structure that comprises: a
first member including: a first inner surface that extends along
and around a first axis, at least a part of the first inner surface
which forms a first hole; and a first outer surface that is
opposite the first inner surface, extends along and around a second
axis different from and in parallel with the first axis, and is
provided with one or more first dents arranged around the second
axis at an interval of a first angular distance; a second member
including: a second inner surface that extends along and around the
second axis and is provided with one or more second dents arranged
around the second axis at an interval of a second angular distance
different from the first angular distance, at least a part of the
second inner surface which forms a second hole that allows the
first member to be housed, in contact with the first outer surface
of the first member housed in the second hole; and a second outer
surface that is opposite the second inner surface, extends along
and around a third axis different from and in parallel with the
second axis, and is provided with one or more third dents arranged
around the third axis at an interval of a third angular distance;
and a third member including a third inner surface that extends
along and around the third axis and is provided with one or more
fourth dents arranged around the third axis at an interval of a
fourth angular distance different from the third angular distance,
at least a part of the third inner surface which forms a third hole
that allows the second member to be housed, in contact with the
second outer surface of the second member housed in the third hole,
a first distance between the first axis and the second axis being
equal to a second distance r between the second axis and the third
axis, the adjustment method comprising: rotating the first member
around the second axis with respect to the second member by an
angle .theta..sub.r1 from a position where the first axis and the
third axis coincide with each other, in accordance with an
eccentric distance R.sub.f between the third axis and a gravity
center of the mounting structure, the gravity center being
represented by polar coordinates (R.sub.f,.theta..sub.f) with
reference to the third axis, the angle .theta..sub.r1 satisfying
the following seventh expression: R.sub.f=r {square root over
(2(1-cos .theta..sub.r1))} Seventh expression rotating the second
member around the third axis with respect to the third member by an
angle .theta..sub.r2 in accordance with an eccentric angle
.theta..sub.f between the third axis and the gravity center, the
angle .theta..sub.r2 satisfying the following eighth expression:
.theta. f = .theta. r 2 - tan - 1 sin .theta. r 1 1 - cos .theta. r
1 + .pi. Eighth expression ##EQU00006## housing a first limiting
member in one of the one or more first dents and one of one or more
the second dents opposing each other, to limit rotation of the
first member and the second member around the second axis; and
housing a second limiting member in one of the one or more third
dents and one of the one or more fourth dents opposing each other,
to limit rotation of the second member and the third member around
the third axis.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is based upon and claims the benefit of
priority from Japanese Patent Application No. 2017-178343, filed on
Sep. 15, 2017, the entire contents of which are incorporated herein
by reference.
FIELD
[0002] Embodiments described herein relate to a mounting structure,
rotational machinery, an air conditioning apparatus, and an
adjustment method.
BACKGROUND
[0003] Rotational machines include a mounting structure for
connecting the shaft of a power source such as a motor and an
object such as a fan, to rotate the object. As an example, the
object is connected to the outer circumference of the mounting
structure with the shaft inserted into a hole of the mounting
structure.
[0004] The gravity center of a rotational object may become
eccentric with respect to the shaft. In such a case, while rotated,
the object may generate vibration.
BRIEF DESCRIPTION OF THE DRAWINGS
[0005] FIG. 1 is a perspective view illustrating an air
conditioning apparatus in a first embodiment;
[0006] FIG. 2 is a perspective view illustrating a main body of an
indoor unit in the first embodiment;
[0007] FIG. 3 is a cross-sectional view illustrating the main body
of the indoor unit in the first embodiment;
[0008] FIG. 4 is an exploded perspective view schematically
illustrating a shaft of a motor and a bushing in the first
embodiment;
[0009] FIG. 5 is a plan view illustrating the bushing in the first
embodiment;
[0010] FIG. 6 is a plan view illustrating a part of the bushing in
the first embodiment;
[0011] FIG. 7 is a plan view illustrating the bushing in which a
first member is rotated in the first embodiment;
[0012] FIG. 8 is a plan view illustrating the bushing in which a
second member is rotated in the first embodiment;
[0013] FIG. 9 is a plan view illustrating another example of the
bushing in the first embodiment;
[0014] FIG. 10 is a plan view illustrating a part of the bushing
according to a second embodiment;
[0015] FIG. 11 is a plan view illustrating a part of the bushing
according to a third embodiment; and
[0016] FIG. 12 is a plan view illustrating a part of the bushing
according to a fourth embodiment.
DETAILED DESCRIPTION
[0017] According to one embodiment, a mounting structure includes a
first member, a second member, a third member, a first limiting
member and a second limiting member. The first member includes a
first inner surface and a first outer surface. The first inner
surface extends along and around a first axis, at least a part of
the first inner surface which forms a first hole. The first outer
surface is opposite the first inner surface, extends along and
around a second axis different from the first axis, and is provided
with one or more first dents arranged around the second axis at an
interval of a first angular distance. The second member includes a
second inner surface and a second outer surface. The second inner
surface extends along and around the second axis and is provided
with one or more second dents arranged around the second axis at an
interval of a second angular distance different from the first
angular distance, at least a part of the second inner surface which
forms a second hole that allows the first member to be housed, in
contact with the first outer surface of the first member. The
second outer surface is opposite the second inner surface, extends
along and around a third axis different from the second axis, and
is provided with one or more third dents arranged around the third
axis at an interval of a third angular distance. The third member
includes a third inner surface that extends along and around the
third axis and is provided with one or more fourth dents arranged
around the third axis at an interval of a fourth angular distance
different from the third angular distance, at least a part of the
third inner surface which forms a third hole that allows the second
member to be housed, in contact with the second outer surface of
the second member. The first limiting member is housed in one of
the one or more first dents and one of the one or more second dents
opposing each other, and limits rotation of the first member and
the second member around the second axis. The second limiting
member is housed in one of the one or more third dents and one of
the one or more fourth dents opposing each other, and limits
rotation of the second member and the third member around the third
axis.
First Embodiment
[0018] The following describes a first embodiment with reference to
FIGS. 1 to 9. In the present specification, constituting elements
according to the embodiments and descriptions thereof are described
with multiple expressions in some cases. The constituting elements
and descriptions thereof described with multiple expressions may be
described with other expressions other than those described herein.
In addition, constituting elements and descriptions thereof that
are not described with multiple expressions may also be described
with other expressions other than those described herein.
[0019] FIG. 1 is a perspective view illustrating an air
conditioning apparatus (hereinafter, referred to as an air
conditioner) 10 in the first embodiment. The air conditioner 10 is
an example of an air conditioning apparatus and rotational
machinery. The air conditioner 10 can also be referred to as an air
handling unit, for example. The rotational machinery is not limited
to the air conditioner 10. Examples of the rotational machinery may
include a mechanism having an industrial motor, a home electrical
appliance such as an electric fan or a washing machine, and other
machines having a power source and a rotational object.
[0020] As illustrated in each drawing, an X-axis, a Y-axis, and a
Z-axis are defined in the specification. The X-axis, the Y-axis,
and the Z-axis are orthogonal to one another. The X-axis is along
the width of the air conditioner 10. The Y-axis is along the length
(the depth) of the air conditioner 10. The Z-axis is along the
height of the air conditioner 10.
[0021] As illustrated in FIG. 1, the air conditioner 10 includes an
indoor unit 11. The indoor unit 11 is connected to an outdoor
condensing unit and a controller that controls the indoor unit 11
and the outdoor condensing unit, for example. The air conditioner
10 may be constructed as an air conditioning system including two
or more indoor units 11 connected to a single controller.
[0022] The indoor unit 11 includes a cover 21 and a main body 22.
The cover 21 is provided on the ceiling of a room in which the
indoor unit 11 is installed, for example. The cover 21 is provided
with a plurality of air inlets 25 and a plurality of air outlets
26. The air outlets 26 can be opened or closed by a louver, for
example.
[0023] FIG. 2 is a perspective view illustrating the main body 22
of the indoor unit 11 in the first embodiment. FIG. 3 is a
cross-sectional view illustrating the main body 22 of the indoor
unit 11 in the first embodiment. As illustrated in FIGS. 2 and 3,
the main body 22 includes a housing 31, a heat exchanger 32, a
motor 33, a turbofan 34, a cap 35, and a bushing 36. The motor 33
is an example of the power source. The turbofan 34 is an example of
a rotational object and a fan. The turbofan 34 can also be referred
to as a centrifugal fan, for example. The rotational object is not
limited to the turbofan 34. The rotational object may be another
fan such as a propeller fan or another rotational object such as a
gear or a pulley, for example. The bushing 36 is an example of a
mounting structure. The bushing 36 can also be referred to as a
connecting component, a bearing, or a member, for example.
[0024] As illustrated in FIG. 3, the housing 31 is formed of a
metal, for example, and includes a top wall 41 and a peripheral
wall 42. The top wall 41 is plate-like lying in the X-Y plane. The
top wall 41 may be provided with ribs to increase the stiffness of
the top wall 41, for example. The peripheral wall 42 is tubular in
shape, extending from the edges of the top wall 41 in a negative
Z-axis direction (oppositely to the arrow of the Z-axis or
downward).
[0025] The housing 31 includes an air passage 45 inside. The air
passage 45 may be formed by the housing 31 or a member mounted
inside the housing 31, for example. The top wall 41 has an inner
surface 41a that faces the air passage 45. The inner surface 41a
faces in the negative Z-axis direction.
[0026] The heat exchanger 32 is disposed in the air passage 45. The
heat exchanger 32 is attached to the inner surface 41a of the top
wall 41 and has a tubular shape extending in the negative Z-axis
direction, for example. The heat exchanger 32 includes piping
through which refrigerant flows, and fins, for example. The heat
exchanger 32 exchanges heat between air passing through the heat
exchanger 32 and the refrigerant to warm or cool the air. The heat
exchanger 32 is not limited to this example.
[0027] The motor 33 is a direct current (DC) motor the rotation
speed of which can be changed by inverter control, for example. The
motor 33 is mounted on the inner surface 41a of the top wall 41
with bolts extending from the inner surface 41a and nuts, for
example.
[0028] The motor 33 has a shaft 33a. The shaft 33a can also be
referred to as a drive shaft or a rotation shaft, for example. The
shaft 33a extends in the negative Z-axis direction. The motor 33 is
driven to rotate the shaft 33a around the central axis of the shaft
33a.
[0029] The turbofan 34 is surrounded by the heat exchanger 32 in
the air passage 45. The turbofan 34 is made of a synthetic resin,
for example. The turbofan 34 may be made of another material. The
turbofan 34 includes a hub 51, a support 52, a connection 53, a
plurality of blades 54, and a shroud 55.
[0030] The hub 51 has a tubular shape extending in the Z-axis
direction. The hub 51 is mounted on the shaft 33a of the motor 33
through the bushing 36. The support 52 has an annular shape lying
in the X-Y plane. The support 52 is disposed closer to the top wall
41 than the hub 51 and surrounds the motor 33.
[0031] The connection 53 has a tubular, substantially circular
truncated cone shape, for example. The connection 53 connects the
end of the hub 51 and the inner circumference of the support 52.
The blades 54 are arranged in annular form and extend in the
negative Z-axis direction from the support 52. The shroud 55 has an
annular shape lying in the X-Y plane and is connected to the edges
of the blades 54.
[0032] The motor 33 rotates the shaft 33a to rotate the turbofan
34. As illustrated with the arrows in FIG. 3, the turbofan 34,
while rotating, sucks air in the room from the air inlets 25
illustrated in FIG. 1 and supplies the air to the heat exchanger
32. The air is warmed or cooled through the heat exchanger 32 and
supplied to the room from the air outlets 26 illustrated in FIG.
1.
[0033] The cap 35 fixes the turbofan 34 and the bushing 36 to the
shaft 33a of the motor 33. The cap 35 is threadably attached to a
male screw in the distal end of the shaft 33a to support the
turbofan 34 and the bushing 36, for example.
[0034] FIG. 4 is an exploded perspective view schematically
illustrating the shaft 33a of the motor 33 and the bushing 36 in
the first embodiment. FIG. 4 illustrates a cross section of the
bushing 36. As illustrated in FIG. 4, the bushing 36 includes a
first member 61, a second member 62, a third member 63, a first pin
64, and a second pin 65. The first pin 64 is an example of a first
limiting member. The second pin 65 is an example of a second
limiting member.
[0035] The first member 61, the second member 62, and the third
member 63 are made of a relatively lightweight metal such as an
aluminum alloy, for example. The first member 61, the second member
62, and the third member 63 are made of the same material.
[0036] The first member 61, the second member 62, and the third
member 63 may be made of another material such as a synthetic
resin. The first member 61, the second member 62, and the third
member 63 may be made of materials different from one another.
[0037] The first member 61 has a tube 71 and a flange 72. The tube
71 has a substantially cylindrical shape extending in the Z-axis
direction. The tube 71 is, thus, provided with a first hole 75 that
extends through the tube 71 in the Z-axis direction. The first hole
75 is not limited to a through hole in the tube 71. The first hole
75 may have a bottom.
[0038] FIG. 5 is a plan view illustrating the bushing 36 in the
first embodiment. As illustrated in FIG. 5, the first hole 75 has a
substantially circular cross section having the center matching the
first central axis C1. The first central axis C1 is an example of
first axis. The first central axis C1 is a virtual central axis of
the first hole 75 extending along the Z-axis. The first hole 75 has
a substantially circular hole extending about the first central
axis C1. In other words, the first hole 75 extends along and around
the first central axis C1. In the first embodiment, the first
central axis C1 substantially coincides with the central axis of
the shaft 33a of the motor 33. The first central axis C1 can also
be referred to as a rotation center.
[0039] As illustrated in FIG. 4, the tube 71 includes a first inner
circumferential surface 71a, a first outer circumferential surface
71b, and two first end faces 71c. The first inner circumferential
surface 71a is an example of a first inner surface. The first outer
circumferential surface is an example of a first outer surface. The
first inner circumferential surface 71a sections (defines) the
first hole 75 and has a substantially cylindrical shape extending
about the center matching the first central axis C1. In other
words, the first inner circumferential surface 71a forms the first
hole 75. A part of the first inner circumferential surface 71a may
form the first hole 75. The first inner circumferential surface 71a
has a substantially cylindrical face extending along and around the
first central axis C1. The first inner circumferential surface 71a
faces the inside of the first hole 75. The first hole 75 is
provided inside the first inner circumferential surface 71a.
[0040] The first outer circumferential surface 71b is opposite the
first inner circumferential surface 71a. As illustrated in FIG. 5,
the first outer circumferential surface 71b has a substantially
cylindrical shape extending about the center matching a second
central axis C2. In other words, the first outer circumferential
surface 71b is a substantially cylindrical face extending along and
around the second central axis C2. The second central axis is an
example of a second axis.
[0041] The second central axis C2 is a virtual central axis of the
first outer circumferential surface 71b extending along the Z-axis.
The second central axis C2 is in parallel with the first central
axis C1 and located at a different position from the first central
axis C1. In other words, the second central axis C2 differs from
the first central axis C1. The first inner circumferential surface
71a and the first hole 75 are eccentric from the first outer
circumferential surface 71b. The second central axis C2 may be
tilted with respect to the first central axis C1.
[0042] The substantially cylindrical first outer circumferential
surface 71b about the second central axis C2 is thus in rotational
symmetry with respect to the second central axis C2. The second
central axis C2 is also a symmetrical axis of the first outer
circumferential surface 71b.
[0043] As illustrated in FIG. 4, the two first end faces 71c face
in the positive (as indicated by the arrow of the Z-axis or upward)
and negative Z-axis directions. The first hole 75 opens to the two
first end faces 71c.
[0044] The tube 71 is provided with a fitting 76. The fitting 76
projects from the first inner circumferential surface 71a toward
the inside of the first hole 75. The length of the fitting 76 is
shorter than that of the first hole 75 in the Z-axis direction. In
other words, the fitting 76 is provided on a part of the first
inner circumferential surface 71a in the Z-axis direction. The
fitting 76 is not limited to this example.
[0045] A part of the first inner circumferential surface 71a may be
provided with a depression or a projection such as the fitting 76
as described in the first embodiment. In this case, the first
central axis C1 passes the center of a circular cross section part
with no depression or projection, of the first hole 75.
Alternatively, the first inner circumferential surface 71a may be
provided with a depression or a projection on the entire first
inner circumferential surface 71a in the Z-axis direction. In this
case, the first central axis C1 passes the center of an arc-shaped
part in the cross section of the first hole 75. When the cross
section of the first hole 75 includes two or more arc-shaped parts,
the first central axis C1 passes the center of an arc-shaped part
of the cross section having the center closest to the geometric
center (centroid) of the cross section of the first hole 75.
[0046] In the above, the cross section of the first hole 75 is the
circular or includes arc-shaped part. However, the cross section of
the first hole 75 may have no arc-shaped part. In this case, the
first central axis C1 passes the symmetrical axis of a rotationally
symmetric cross section with no depression or projection, of the
first hole 75. Depressions or projections may be provided on the
entirety of the first inner circumferential surface 71a in the
Z-axis direction. In this case, the first central axis C1 passes
the symmetrical axis of a largest rotationally symmetric part in
the cross section of the first hole 75. When the shape of the first
hole 75 is not any of the examples above, the first central axis C1
passes the geometric center of the cross section of the first hole
75.
[0047] The shaft 33a of the motor 33 is inserted into the first
hole 75. The shaft 33a is what is called a D-cut shaft with a
cutout 33b. The fitting 76 is fitted into the cutout 33b while the
shaft 33a is inserted into the first hole 75. As a result, the
rotation of the shaft 33a is transmitted to the first member
61.
[0048] The flange 72 projects from the first outer circumferential
surface 71b of the tube 71. The flange 72 is substantially circular
plate-like lying in the X-Y plane. The flange 72 may have another
shape.
[0049] The flange 72 projects from the end of the first outer
circumferential surface 71b in the positive Z-axis direction. The
flange 72 has a first surface 72a and a second surface 72b. The
first surface 72a is substantially flat, facing in the positive
Z-axis direction. The first surface 72a are continuous with one of
the first end faces 71c. The second surface 72b is opposite the
first surface 72a and substantially flat, facing in the negative
the Z-axis direction.
[0050] The second member 62 has a substantially cylindrical shape
extending in the Z-axis direction. The second member 62 is thus
provided with a second hole 81 that extends through the second
member 62 in the Z-axis direction. The second hole 81 is not
limited to a through hole in the second member 62. The second hole
81 may have a bottom.
[0051] As illustrated in FIG. 5, the second hole 81 has a
substantially circular cross section with the center matching the
second central axis C2. The second central axis C2 is a virtual
central axis of the second hole 81 extending along the Z-axis. The
second hole 81 is a substantially circular hole, extending around
the center matching the second central axis C2. In other words, the
second hole 81 extends along and around the second central axis
C2.
[0052] As illustrated in FIG. 4, the second member 62 includes a
second inner circumferential surface 62a, a second outer
circumferential surface 62b, and two second end faces 62c. The
second inner circumferential surface 62a is an example of a second
inner surface. The second outer circumferential surface 62b is an
example of a second outer surface. The second inner circumferential
surface 62a sections (defines) the second hole 81 and has a
substantially cylindrical shape about the center coinciding with
the second central axis C2. In other words, the second inner
circumferential surface 62a forms the second hole 81. A part of the
second inner circumferential surface 62a may form the second hole
81. That is, the second inner circumferential surface 62a is a
substantially cylindrical face, extending along and around the
second central axis C2. The second inner circumferential surface
62a faces the inside of the second hole 81. The second hole 81 is
provided inside the second inner circumferential surface 62a.
[0053] The substantially cylindrical second inner circumferential
surface 62a about the second central axis C2 is thus in rotational
symmetry with respect to the second central axis C2. The second
central axis C2 is also a symmetrical axis of the second inner
circumferential surface 62a.
[0054] As described above, the center (the second central axis C2)
of the second hole 81 and the second inner circumferential surface
62a and the center (the second central axis C2) of the first outer
circumferential surface 71b of the tube 71 of the first member 61
substantially coincide with each other. Because of this, the second
member 62 can rotate around the second central axis C2 with respect
to the first member 61 while the first member 61 and the second
member 62 are not fixed to each other and thus are movable.
[0055] The tube 71 of the first member 61 is housed in the second
hole 81. A radius of the second hole 81 and a radius of the first
outer circumferential surface 71b of the tube 71 of the first
member 61 are practically equal to each other. The second inner
circumferential surface 62a thus contact with the first outer
circumferential surface 71b of the tube 71 housed in the second
hole 81 and thereby limits the movement of the second member 62
with respect to the first member 61 in a direction intersecting the
Z-axis. A part of the second inner circumferential surface 62a may
be slightly apart from the first outer circumferential surface
71b.
[0056] The second outer circumferential surface 62b is opposite the
second inner circumferential surface 62a. As illustrated in FIG. 5,
the second outer circumferential surface 62b is a cylindrical face
extending about a third central axis C3. The cylindrical second
outer circumferential surface 62b extends along and around the
third central axis C3. The third central axis C3 is an example of a
third axis.
[0057] A third central axis C3 is a virtual central line of the
second outer circumferential surface 62b extending along the
Z-axis. The third central axis C3 is in parallel with the first
central axis C1 and the second central axis C2, and located at a
different position from the second central axis C2. In other words,
the third central axis C3 differs from the second central axis C2.
The second inner circumferential surface 62a and the second hole 81
are eccentric from the second outer circumferential surface 62b.
The third central axis C3 may be tilted with respect to the first
central axis C1. The third central axis C3 may be tilted with
respect to the second central axis C2.
[0058] A distance r.sub.12 between the first central axis C1 and
the second central axis C2 is substantially equal to a distance
r.sub.23 between the second central axis C2 and the third central
axis C3. As a result, as illustrated in FIG. 5, the first central
axis C1 and the third central axis C3 can match each other.
[0059] The cylindrical second outer circumferential surface 62b
extending about the third central axis C3 is then in rotational
symmetry with respect to the third central axis C3. The third
central axis C3 is also a symmetrical axis of the second outer
circumferential surface 62b.
[0060] As illustrated in FIG. 4, the two second end faces 62c face
in the positive and negative Z-axis directions, respectively. The
second hole 81 opens to the two second end faces 62c. While the
tube 71 is housed in the second hole 81, the second end face 62c
facing in the positive Z-axis direction is in contact with the
second surface 72b of the flange 72. The flange 72 supports the
second member 62 to limit the movement of the second member 62 with
respect to the first member 61 in the positive Z-axis
direction.
[0061] The third member 63 has a substantially cylindrical shape
extending in the Z-axis direction. The third member 63 is thus
provided with a third hole 85 that extends through the third member
63 in the Z-axis direction. The third hole 85 is not limited to a
through hole in the third member 63. The third hole 85 may have a
bottom.
[0062] As illustrated in FIG. 5, the third hole 85 has a
substantially circular cross section with the center matching the
third central axis C3. The third central axis C3 is a virtual
central axis of the third hole 85 extending along the Z-axis. The
third hole 85 is a substantially circular hole, extending about the
third central axis C3. The third hole 85 extends along and around
the third central axis C3.
[0063] As illustrated in FIG. 4, the third member 63 includes a
third inner circumferential surface 63a, a third outer
circumferential surface 63b, and two third end faces 63c. The third
inner circumferential surface 63a is an example of a third inner
surface. The third inner circumferential surface 63a sections
(defines) the third hole 85 and has a substantially cylindrical
shape extending about the center matching the third central axis
C3. In other words, the third inner circumferential surface 63a
forms the third hole 85. A part of the third inner circumferential
surface 63a may form the third hole 85. The third inner
circumferential surface 63a is a substantially cylindrical face,
extending along and around the third central axis C3. The third
inner circumferential surface 63a faces the inside of the third
hole 85. The third hole 85 is provided inside the third inner
circumferential surface 63a. The second inner circumferential
surface 62a and the second hole 81 are eccentric from the third
inner circumferential surface 63a.
[0064] The substantially cylindrical third inner circumferential
surface 63a extending about the third central axis C3 is in
rotational symmetry with respect to the third central axis C3. The
third central axis C3 is also a symmetrical axis of the third inner
circumferential surface 63a.
[0065] As described above, the center (the third central axis C3)
of the third hole 85 and the third inner circumferential surface
63a and the center (the third central axis C3) of the second outer
circumferential surface 62b of the second member 62 practically
coincide with each other. The third member 63 can thus rotate
around the third central axis C3 with respect to the second member
62 when the second member 62 and the third member 63 are not fixed
to each other and thus are movable.
[0066] The second member 62 is housed in the third hole 85. A
radius of the third hole 85 and a radius of the second outer
circumferential surface 62b of the second member 62 are practically
equal to each other. The third inner circumferential surface 63a is
thus in contact with the second outer circumferential surface 62b
of the second member 62 housed in the third hole 85, and thereby
limits the movement of the third member 63 with respect to the
second member 62 in a direction intersecting the Z-axis. A part of
the third inner circumferential surface 63a may be slightly apart
from the second outer circumferential surface 62b.
[0067] The third outer circumferential surface 63b is opposite the
third inner circumferential surface 63a. As illustrated in FIG. 5,
the third outer circumferential surface 63b has a cylindrical shape
extending about the center matching the third central axis C3. The
center (the third central axis C3) of the third outer
circumferential surface 63b and the center (the third central axis
C3) of the third inner circumferential surface 63a practically
coincide with each other. In other words, the third inner
circumferential surface 63a and the third outer circumferential
surface 63b are concentric.
[0068] The third outer circumferential surface 63b is a
substantially cylindrical face extending along and around the third
central axis C3. The third outer circumferential surface 63b is in
rotational symmetry with the third central axis C3. The third
central axis C3 is also a symmetrical axis of the third outer
circumferential surface 63b.
[0069] As illustrated in FIG. 3, the third member 63 is formed
integrally with the hub 51 of the turbofan 34 by insert molding,
for example. In the first embodiment, the third outer
circumferential surface 63b of the third member 63 is connected to
the hub 51 of the turbofan 34. Alternatively, for example, the
third member 63 and the turbofan 34 may be formed of the same
material into a single component.
[0070] As illustrated in FIG. 4, the two third end faces 63c face
in the positive and negative Z-axis directions, respectively. The
third hole 85 opens to the two third end faces 63c. The tube 71 is
housed in the second hole 81 while the second member 62 is housed
in the third hole 85. As a result, the third end face 63c facing in
the positive Z-axis direction is in contact with the second surface
72b of the flange 72. The flange 72 supports the third member 63 to
limit the movement of the third member 63 with respect to the first
member 61 in the positive Z-axis direction.
[0071] While the tube 71 is housed in the second hole 81 and the
second member 62 is housed in the third hole 85, the first end face
71c, the second end face 62c, and the third end face 63c, facing in
the Z-axis negative direction, form substantially the same plane.
The cap 35 attached to the shaft 33a supports the first end face
71c, the second end face 62c, and the third end face 63c, facing in
the Z-axis negative direction, and limits the movement of the
second member 62 and the third member 63 with respect to the first
member 61 in the negative Z-axis direction.
[0072] A sheet 78 may be interposed between the cap 35, and the
first member 61, the second member 62, and the third member 63. The
sheet 78 is a substantially annular sheet, formed of an elastic
material such as a synthetic rubber, for example. Owing to the
sheet 78, the cap 35 can stably support the first end face 71c, the
second end face 62c, and the third end face 63c, facing in the
negative Z-axis direction, even when having a difference in
level.
[0073] FIG. 6 is a plan view illustrating a part of the bushing 36
in the first embodiment. As illustrated in FIG. 6, the first member
61 is provided with a plurality of first dents 91 on the first
outer circumferential surface 71b. The first dents 91 can be
referred to as grooves, depressions, or cutouts, for example.
[0074] The first dents 91 are grooves with a substantially
semi-circle cross section, extending in the Z-axis direction. The
first dents 91 may have another shape. The first dents 91 open to
the first outer circumferential surface 71b and the first end face
71c of the tube 71 facing in the negative Z-axis direction.
[0075] The first dents 91 are arranged around the second central
axis C2 at a first pitch P.sub.1. In other words, the first dents
91 are aligned around the second central axis C2 at intervals of a
constant angle (the first pitch P.sub.1). The first pitch P.sub.1
is an example of a first angular distance and a fourth angle
.theta..sub.4. The first pitch P.sub.1 corresponds to a difference
in angles between the adjacent first dents 91 around the second
central axis C2. In the first embodiment, the first pitch P.sub.1
is set to 25 degrees.
[0076] The difference in angles between the adjacent first dents 91
may differ from the first pitch P.sub.1. For example, when the
first pitch P.sub.1 differs from a divisor of 360-degree angle, and
the first dents 91 are arranged around the second central axis C2
at the first pitch P.sub.1 in order, the difference in angles
between the initially arranged first dent 91 and the last-arranged
first dent 91 differs from the first pitch P.sub.1.
[0077] The second member 62 is provided with a plurality of second
dents 92 on the second inner circumferential surface 62a. The
second member 62 is also provided with a plurality of third dents
93 on the second outer circumferential surface 62b. The second
dents 92 and the third dents 93 can also be referred to as grooves,
depressions, or cutouts, for example.
[0078] The second dents 92 are grooves with a substantially
semi-circle cross section, extending in the Z-axis direction. The
second dents 92 may have another shape. A radius of the second
dents 92 is substantially equal to that of the first dents 91. The
second dent 92 opens to the second inner circumferential surface
62a and to both the second end faces 62c of the second member
62.
[0079] The second dents 92 are arranged around the second central
axis C2 at a second pitch P.sub.2. The second pitch P.sub.2 is an
example of a second angular distance and a third angle
.theta..sub.3. The second pitch P.sub.2 corresponds to a difference
in angles between the adjacent second dents 92 around the second
central axis C2. In the first embodiment, the second pitch P.sub.2
is set to 24 degrees. That is, the second pitch P.sub.2 differs
from the first pitch P.sub.1. As with the first dents 91, a
difference in angles between the adjacent second dents 92 may
differ from the second pitch P.sub.2.
[0080] The third dents 93 are grooves with a substantially
semi-circle cross section, extending in the Z-axis direction. The
third dent 93 may have another shape. The third dent 93 opens to
the second outer circumferential surface 62b and to both the second
end faces 62c of the second member 62.
[0081] The third dents 93 are arranged around the third central
axis C3 at a third pitch P.sub.3. The third pitch P.sub.3 is an
example of a third angular distance and a first angle
.theta..sub.1. The third pitch P.sub.3 corresponds to a difference
in angles between the adjacent third dents 93 around the third
central axis C3. In the first embodiment, the third pitch P.sub.3
is set to 18 degrees. As with the first dents 91, the difference in
angles between the adjacent third dents 93 may differ from the
third pitch P.sub.3.
[0082] The third member 63 is provided with a plurality of fourth
dents 94 on the third inner circumferential surface 63a. The fourth
dents 94 can also be referred to as grooves, depressions, or
cutouts, for example. The fourth dents 94 are grooves with a
substantially semi-circle cross section, extending in the Z-axis
direction. The fourth dents 94 may have another shape. A radius of
the fourth dents 94 is substantially equal to that of the third
dents 93. The fourth dent 94 opens to the third inner
circumferential surface 63a and to both the third end faces 63c of
the third member 63.
[0083] The fourth dents 94 are arranged around the third central
axis C3 at a fourth pitch P.sub.4. The fourth pitch P.sub.4 is an
example of a fourth angular distance and a second angle
.theta..sub.2. The fourth pitch P.sub.4 corresponds to a difference
in angles between the adjacent fourth dents 94 around the third
central axis C3. In the first embodiment, the fourth pitch P.sub.4
is set to 19 degrees. The fourth pitch P.sub.4 differs from the
third pitch P.sub.3. The first pitch P.sub.1, the second pitch
P.sub.2, the third pitch P.sub.3, and the fourth pitch P.sub.4 are
all larger than zero degree and smaller than 360 degrees. As with
the first dents 91, the difference in angles between the adjacent
fourth dents 94 may differ from the fourth pitch P.sub.4.
[0084] As illustrated in FIG. 4, the first pin 64 and the second
pin 65 both have a substantially columnar shape. The first pin 64
and the second pin 65 may have another shape. A radius of the first
pin 64 is substantially equal to that of the first dents 91 and
that of the second dents 92. A radius of the second pin 65 is
substantially equal to that of the third dents 93 and that of the
fourth dents 94.
[0085] As illustrated in FIG. 5, the first pin 64 is housed in one
of the first dents 91 and one of the second dents 92 opposing each
other. The first pin 64 limits a relative rotation between the
first member 61 and the second member 62 around the second central
axis C2. The first member 61 and the second member 62 thus mutually
transmit torque, and are integrally rotatable around the second
central axis C2.
[0086] The second pin 65 is housed in one of the third dents 93 and
one of the fourth dents 94 opposing each other. The second pin 65
limits a relative rotation between the second member 62 and the
third member 63 around the third central axis C3. The second member
62 and the third member 63 thus mutually transmit torque and are
integrally rotatable around the third central axis C3.
[0087] The first member 61, the second member 62, and the third
member 63 described above are assembled in accordance with the
position of the gravity center of the turbofan 34 integrated with
the third member 63. Specifically, the first member 61, the second
member 62, and the third member 63 are arranged to rotate around
their respective centers (the second central axis C2 or the third
central axis C3) with the central axis of the shaft 33a of the
motor 33 matching the gravity center of the turbofan 34. In other
words, the first central axis C1 and the gravity center of the
turbofan 34 are made coincident with each other.
[0088] To measure the position of the gravity center of the
turbofan 34, the turbofan 34 is placed on three
triangularly-arranged pressure sensors. Alternatively, the position
of the gravity center of the turbofan 34 may be measured by
rotating the turbofan 34.
[0089] With the first central axis C1 and the gravity center of the
turbofan 34 coinciding with each other, the first pin 64 is housed
in the opposing first dent 91 and second dent 92 while the second
pin 65 is housed in the opposing third dent 93 and fourth dent 94.
Thereby, the shaft 33a of the motor 33 can transmit the rotation
(torque) to the turbofan 34 via the first member 61, the second
member 62, and the third member 63.
[0090] The gravity center of the turbofan 34 may be located at any
position on the first central axis C1 along the Z-axis. The
position of the gravity center of the turbofan 34 can coincide with
the first central axis C1 in a plan view in the extending direction
of the first central axis C1 (the positive or negative Z-axis
direction).
[0091] Due to the first central axis C1 and the gravity center of
the turbofan 34 coinciding with each other, it is possible to
prevent the rotating turbofan 34 from causing vibration. If the
first central axis C1 differs from the gravity center of the
turbofan 34, the vibration from the rotating turbofan 34 can be
reduced by setting the first central axis C1 closer to the gravity
center of the turbofan 34.
[0092] For example, with the gravity center of the turbofan 34
coinciding with the third central axis C3 being the center of the
turbofan 34 and the third member 63, the first member 61, the
second member 62, and the third member 63 are placed as illustrated
in FIG. 5. The first central axis C1 and the third central axis C3
match each other. In this case, the position of the second central
axis C2 may differ from the position in FIG. 5.
[0093] By the arrangement of the first member 61, the second member
62, and the third member 63 as illustrated in FIG. 5, the central
axis (the first central axis C1) of the shaft 33a of the motor 33
substantially coincides with the position of the gravity center of
the turbofan 34 (the third central axis C3). This can prevent the
occurrence of vibration from the turbofan 34 in rotation.
[0094] Misalignment of the third member 63 by insert molding may,
for example, lead to the deviation of the gravity center of the
turbofan 34 from the third central axis C3. In this case, the first
member 61, the second member 62, and the third member 63 are
rotated around their respective centers (the second central axis C2
or the third central axis C3) from their positions illustrated in
FIG. 5. The following describes position alignment between the
first central axis C1 and a gravity center CG which is differently
positioned from the third central axis C3. For the purpose of
explanation, the first central axis C1 and the third central axis
C3 initially coincide with each other as illustrated in FIG. 5. The
position alignment between the gravity center CG and the first
central axis C1 is not limited to this example.
[0095] The position of the gravity center CG is represented by
polar coordinates (R.sub.f,.theta..sub.f) with reference to the
third central axis C3 as the origin. The gravity center CG is
separated from the third central axis C3 with a distance R.sub.f
and at an angle .theta..sub.f around the third central axis C3 from
the position illustrated in FIG. 5.
[0096] FIG. 7 is a plan view illustrating the bushing 36 in which
the first member 61 is rotated in the first embodiment. As
illustrated in FIG. 7, the first member 61 is rotated around the
second central axis C2 by an angle GO with respect to the second
member 62. The rotation results in changing a distance between the
first central axis C1 and the third central axis C3 and placing the
first central axis C1 apart from the third central axis C3 by a
distance R.sub.f. That is, the first member 61 is rotated around
the second central axis C2 with respect to the second member 62 to
adjust an amount of eccentricity of the first central axis C1 with
respect to the third central axis C3.
[0097] FIG. 8 is a plan view illustrating the bushing 36 in which
the second member 62 is rotated in the first embodiment. Next, the
second member 62 is rotated around the third central axis C3 by an
angle .theta..sub.r2 with respect to the third member 63. The
rotation results in changing the angle of the first central axis C1
with respect to the third central axis C3 and placing the first
central axis C1 at the polar coordinates (R.sub.f,.theta..sub.f),
which matches the gravity center CG. That is, the second member 62
is rotated around the third central axis C3 with respect to the
third member 63 to adjust an angle of eccentricity of the first
central axis C1 with respect to the third central axis C3.
[0098] The rotation angle .theta..sub.r1 of the first member 61 for
placing the first central axis C1 at the polar coordinates
(R.sub.f,.theta..sub.f) is found by the following expression 1:
R.sub.f=r {square root over (2(1-cos .theta..sub.r1))} Expression
1
That is, the first member 61 is rotated around the second central
axis C2 with respect to the second member 62 in accordance with an
eccentric distance R.sub.f between the gravity center CG and the
third central axis C3.
[0099] The rotation angle 682 of the second member 62 for placing
the first central axis C1 at the polar coordinates
R.sub.f,.theta..sub.f) is found by the following expression 2:
.theta. f = .theta. r 2 - tan - 1 sin .theta. r 1 1 - cos .theta. r
1 + .pi. Expression 2 ##EQU00001##
The second member 62 is rotated around the third central axis C3
with respect to the third member 63 in accordance with an eccentric
angle .theta..sub.f between the gravity center CG and the third
central axis C3.
[0100] The rotation of the first member 61 and the second member 62
as described above allows the central axis of the shaft 33a of the
motor 33 and the gravity center CG of the turbofan 34 to
substantially coincide with each other. In this case, the turbofan
34 and the shaft 33a of the motor 33 appear to be eccentric from
each other, however, vibration from the rotating turbofan 34 is
reduced.
[0101] FIG. 9 is a plan view illustrating another example of the
bushing 36 in the first embodiment. In the example illustrated in
FIG. 9, the eccentric distance R.sub.f between the gravity center
CG and the third central axis C3 is set to a maximum value that
allows the bushing 36 to place the first central axis C1 and the
gravity center CG at the same position. The first member 61 is
rotated with respect to the second member 62 by 180 degrees, which
places the first central axis C1 at the same position as the
gravity center CG illustrated in FIG. 9.
[0102] In the example in FIG. 9, the eccentric distance R.sub.f is
represented by the following expression 3:
R.sub.f=r.sub.12+r.sub.23=2r.sub.12=2r.sub.23 Expression 3
[0103] From the expression 3, it can be understood that the bushing
36 can place the first central axis C1 and the gravity center CG at
the same position, when the eccentric distance R.sub.f is equal to
or smaller than a sum of the distance r.sub.12 and the distance
r.sub.23.
[0104] As described above, the second member 62 is rotated around
the second central axis C2 with respect to the first member 61 in
accordance with the gravity center CG of the turbofan 34. The first
pin 64 is then housed in the opposing first dent 91 and second dent
92, thereby limiting a relative rotation between the first member
61 and the second member 62. Thereby, the second member 62 can be
attached to the first member 61 at different angles around the
second central axis C2 relative to the first member 61.
[0105] In addition, the third member 63 is rotated around the third
central axis C3 with respect to the second member 62 in accordance
with the gravity center CG of the turbofan 34. The second pin 65 is
then housed in the opposing third dent 93 and fourth dent 94,
thereby limiting a relative rotation between the second member 62
and the third member 63. Thereby, the third member 63 can be
attached to the second member 62 at different angles around the
third central axis C3 relative to the second member 62. As a
result, the central axis (the first central axis C1) of the shaft
33a of the motor 33 and the gravity center CG of the turbofan 34
can be made coincident with each other.
[0106] In the first embodiment, the angle of the second member 62
with respect to the first member 61 can be adjusted around the
second central axis C2 in unit of 1 degree. The angle of the third
member 63 with respect to the second member 62 can be adjusted
around the third central axis C3 in unit of 1 degree.
[0107] The first pitch P.sub.1, the second pitch P.sub.2, the third
pitch P.sub.3, and the fourth pitch P.sub.4 are set to be able to
adjust the relative angle among the first member 61, the second
member 62, and the third member 63 in unit of 1 degree. The
following describes an example of setting the first pitch P.sub.1,
the second pitch P.sub.2, the third pitch P.sub.3, and the fourth
pitch P.sub.4 in detail. The third pitch P.sub.3 and the fourth
pitch P.sub.4 are set in the following manner.
[0108] A difference .DELTA.P.sub.34 between the third pitch P.sub.3
and the fourth pitch P.sub.4 is set to a divisor of at least one of
the third pitch P.sub.3 and the fourth pitch P.sub.4. The
difference .DELTA.P.sub.34 is an example of a first difference and
a difference .DELTA..theta..sub.12.
[0109] The difference .DELTA.P.sub.34 represents the absolute value
of a value obtained by subtracting the fourth pitch P.sub.4 from
the third pitch P.sub.3. In the first embodiment, the difference
.DELTA.P.sub.34 between 18 degrees of the third pitch P.sub.3 and
19 degrees of the fourth pitch P.sub.4 is 1 degree. The difference
.DELTA.P.sub.34 is thus both a divisor of the third pitch P.sub.3
and a divisor of the fourth pitch P.sub.4. The third pitch P.sub.3
is equally divided into n.sub.a parts by the difference
.DELTA.P.sub.34.
[0110] In addition, at least one of the third pitch P.sub.3 and the
fourth pitch P.sub.4 is set to a divisor of 360 degrees. In the
first embodiment, the third pitch P.sub.3 is set to 18 degrees
being a divisor of 360 degrees. 360 degrees are equally divided
into n.sub.b parts by the third pitch P.sub.3. The third pitch
P.sub.3 may differ from a divisor of 360 degrees.
[0111] In the first embodiment, the difference .DELTA.P.sub.34
represents a divisor of 360 degrees. In this case, the third pitch
P.sub.3 and the fourth pitch P.sub.4 are set so as to satisfy the
following expression 4:
( n a - 1 ) 2 n a - n b < 0 ( if P 3 > P 4 ) ( n a 2 - 1 ) 2
n a - n b < 0 ( if P 3 < P 4 ) Expression 4 ##EQU00002##
[0112] In the first embodiment, a value resulting from the
expression 4 is approximately -2.056 below zero. The third pitch
P.sub.3 and the fourth pitch P.sub.4 in the first embodiment thus
satisfy the expression 4.
[0113] When the difference .DELTA.P.sub.34 differs from a divisor
of 360 degrees, the third pitch P.sub.3 and the fourth pitch
P.sub.4 are set so as to satisfy the following expression 5:
(P.sub.3-.DELTA.P.sub.34).sup.2-180.degree..DELTA.P.sub.34<0 (if
P.sub.3>P.sub.4)
P.sub.3.sup.2-.DELTA.P.sub.34.sup.2-180.degree..DELTA.P.sub.34<0
(if P.sub.3>P.sub.4) Expression 5
[0114] By setting the third pitch P.sub.3 and the fourth pitch
P.sub.4 to satisfy the expression 4 or expression 5, the position
(angle) of the third member 63 with respect to the second member 62
can be properly adjusted over the whole circumference around the
third central axis C3 in unit of the difference .DELTA.P.sub.34. In
other words, the angle of the third member 63 with respect to the
second member 62 is adjustable in unit of 1 degree in the range of
360-degree angle.
[0115] There are multiple combinations of the angles of the third
pitch P.sub.3 and the fourth pitch P.sub.4 that satisfy the
expression 4 or expression 5. Among the multiple combinations, the
closer to zero the value obtained by expression 4 or expression 5
is, the less the numbers of the third dents 93 and fourth dents 94
are.
[0116] In the first embodiment, when the difference .DELTA.P.sub.34
is 1 degree, i.e., the third pitch P.sub.3 of 18 degrees and the
fourth pitch P.sub.4 of 19 degrees, among the multiple
combinations, this combination results in the value closest to zero
from the expression 4. The combination of the third pitch P.sub.3
and the fourth pitch P.sub.4 in the first embodiment is thus the
one to set the smallest numbers of the third dents 93 and the
fourth dents 94.
[0117] Likewise, when the difference .DELTA.P.sub.34 differs from a
divisor of 360 degrees, the combination of the third pitch P.sub.3
and the fourth pitch P.sub.4 is set to the one resulting in the
value closest to zero from the expression 5 among the multiple
combinations. In this case, the combination of the third pitch
P.sub.3 and the fourth pitch P.sub.4 is the one to set the smallest
numbers of the third dents 93 and the fourth dents 94.
[0118] After the third pitch P.sub.3 and the fourth pitch P.sub.4
are set, the first pitch P.sub.1 and the second pitch P.sub.2 are
set in the following manner.
[0119] A difference .DELTA.P.sub.12 between the first pitch P.sub.1
and the second pitch P.sub.2 is set to a divisor of at least one of
the first pitch P.sub.1 and the second pitch P.sub.2. The
difference .DELTA.P.sub.12 is an example of a second difference and
a difference .DELTA..theta..sub.34.
[0120] The difference .DELTA.P.sub.12 is the absolute value of a
value obtained by subtracting the second pitch P.sub.2 from the
first pitch P.sub.1. In the first embodiment, the difference
.DELTA.P.sub.12 between 25 degrees of the first pitch P.sub.1 and
24 degrees of the second pitch P.sub.2 is 1 degree. The difference
.DELTA.P.sub.12 is thus both a divisor of the first pitch P.sub.1
and a divisor of the second pitch P.sub.2. The second pitch P.sub.2
is equally divided into n.sub.c parts by the difference
.DELTA.P.sub.12.
[0121] In addition, at least one of the first pitch P.sub.1 and the
second pitch P.sub.2 is set to a divisor of 360 degrees. In the
first embodiment, 24 degrees of the second pitch P.sub.2 is a
divisor of 360 degrees. 360 degrees is equally divided into
1/2n.sub.d by the second pitch P.sub.2. The second pitch P.sub.2
may differ from a divisor of 360 degrees.
[0122] In the first embodiment, the difference .DELTA.P.sub.12 is a
divisor of 360 degrees and the number of the first dents 91 is N.
In this case, the first pitch P.sub.1 and the second pitch P.sub.2
are set so as to satisfy the following expressions 6 and 7.
( n c - 1 ) 2 n c - 2 n d < 0 ( if P 2 > P 1 ) n c 2 - 1 n c
- 2 n d < 0 ( if P 2 < P 1 ) Expression 6 180 .DELTA. P 12
.ltoreq. n d ( N - 1 ) ( if P 1 is not a divisor of 720 ) 180
.DELTA. P 12 .ltoreq. n d N ( if P 1 is a divisor of 720 )
Expression 7 ##EQU00003##
[0123] As described above, by the rotation of the first member 61
with respect to the second member 62 around the second central axis
C2 by the angle .theta..sub.r1, the eccentric distance of the first
central axis C1 with respect to the third central axis C3 can be
equal to the eccentric distance R.sub.f of the gravity center CG.
As represented in the expression 1, the eccentric distance R.sub.f
is the function of cosine of the angle .theta..sub.r1. The cosine
function has 180-degree symmetry. Because of the 180-degree
symmetry, by equally dividing 360 degrees into 1/2n.sub.d parts by
the second pitch P.sub.2 and setting the first pitch P and the
second pitch P.sub.2 to satisfy the expression 6, the angles made
by the combinations of the first dents 91 and the second dents 92
can be prevented from overlapping. This can reduce the numbers of
the first dents 91 and the second dents 92.
[0124] In the first embodiment, a value resulting from the
expression 6 is approximately -6.042 below zero. That is, the first
pitch P.sub.1 and the second pitch P.sub.2 in the first embodiment
both satisfy the expression 6. The first pitch P.sub.1 and the
second pitch P.sub.2 in the first embodiment also satisfy the
expression 7.
[0125] When a value obtained by dividing 360 degrees by
.DELTA.P.sub.12 is an odd number, the first pitch P.sub.1 and the
second pitch P.sub.2 may be set so as to satisfy the following
expression 8 and only one first dent 91 may be provided on the
first outer circumferential surface 71b. For example, when
.DELTA.P.sub.12 is 8, 24, 40, 72, or 120 degrees, the value
obtained by dividing 360 degrees by .DELTA.P.sub.12 is an odd
number.
P.sub.2=2.DELTA.P.sub.12 Expression 8
[0126] When the difference .DELTA.P.sub.12 differs from a divisor
of 360 degrees, the first pitch P.sub.1 and the second pitch
P.sub.2 are set so as to satisfy the following expression 9:
(P.sub.2-.DELTA.P.sub.12).sup.2-180.degree..DELTA.P.sub.12<0 (if
P.sub.2>P.sub.1)
P.sub.2.sup.2-.DELTA.P.sub.12.sup.2-.DELTA.P.sub.12<0 (if
P.sub.2<P.sub.1) Expression 9
[0127] By setting the first pitch P.sub.1 and the second pitch
P.sub.2 to satisfy the expressions 6 and 7, the expression 8, or
the expression 9, it is made possible to properly adjust the
position (angle) of the second member 62 with respect to the first
member 61 over the whole circumference around the second central
axis C2 in unit of the difference .DELTA.P.sub.12.
[0128] There may be multiple combinations of the angles of the
first pitch P.sub.1 and the second pitch P.sub.2 that satisfy the
expressions 6 and 7 or the expression 9. Among the multiple
combinations, the closer to zero the value resulting from the
expression 6 or the expression 9 is, the less the numbers of the
first dents 91 and the second dents 92 are.
[0129] In the first embodiment, when the difference .DELTA.P.sub.12
is 1 degree, i.e., 25 degrees of the first pitch P.sub.1 and 24
degrees of the second pitch P.sub.2, among the multiple
combinations, this combination results in the value closest to zero
from the expression 6. That is, the combination of the first pitch
P.sub.1 and the second pitch P.sub.2 in the first embodiment is the
one to set the smallest numbers of the first dents 91 and the
second dents 92.
[0130] When a value obtained by dividing 360 degrees by
.DELTA.P.sub.12 is an odd number, the combination of the first
pitch P.sub.1 and the second pitch P.sub.2 satisfying the
expression 8 can be the one to set the smallest numbers of the
first dents 91 and the second dents 92. In this case, from between
the combination of the first pitch P.sub.1 and the second pitch
P.sub.2 satisfying the expressions 6 and 7 and the combination
thereof satisfying the expression 8, the one to set the smaller
number of the dents 91 and 92 is selected, for example. When
.DELTA.P.sub.12 is 72 degrees, for example, the combination of the
first pitch P.sub.1 and the second pitch P.sub.2 satisfying the
expression 8 is the one to set the smallest numbers of the first
dents 91 and the second dents 92.
[0131] When the difference .DELTA.P.sub.12 differs from a divisor
of 360 degrees, the combination of the first pitch P.sub.1 and the
second pitch P.sub.2 is set to the one resulting in the value
closest to zero from the expression 9 among the multiple
combinations. In this case, the combination of the first pitch
P.sub.1 and the second pitch P.sub.2 results in the smallest
numbers of the first dents 91 and the second dents 92.
[0132] In the air conditioner 10 including the bushing 36 in the
first embodiment, the first central axis C1 of the first inner
circumferential surface 71a of the first member 61 is eccentric
from the second central axis C2 of the first outer circumferential
surface 71b of the first member 61. In addition, the second central
axis C2 of the second inner circumferential surface 62a of the
second member 62 is eccentric from the third central axis C3 of the
second outer circumferential surface 62b of the second member 62.
The first member 61 is housed in the second hole 81 of the second
member 62 while the second member 62 is housed in the third hole 85
of the third member 63. The second member 62 is disposed at a
desired angle around the second central axis C2 relative to the
first member 61. The first pin 64 limits the rotation of the second
member 62 around the second central axis C2 with respect to the
first member 61. The third member 63 is disposed at a desired angle
around the third central axis C3 relative to the second member 62.
The second pin 65 limits the rotation of the third member 63 around
the third central axis C3 with respect to the second member 62.
Thereby, the third central axis C3 can be made coincident with the
first central axis C1 or placed at a desired position different
from the first central axis C1. The first central axis C1 can
coincide with the gravity center CG of the bushing 36, for example,
thereby preventing the turbofan 34 to which the bushing 36 is
attached from being vibrated and generating noise due to the
vibration.
[0133] The first dents 91 are arranged at the first pitch P.sub.1
around the second central axis C2. The second dents 92 are arranged
at the second pitch P.sub.2 around the second central axis C2
different from the first pitch P.sub.1. The first pin 64 is housed
in one of the first dents 91 and one of the second dents 92,
thereby limiting the relative rotation between the first member 61
and the second member 62. This makes it possible to more finely
adjust the position (angle) of the second member 62 around the
second central axis C2 relative to the first member 61, in unit of
the difference .DELTA.P.sub.12 between the first pitch P.sub.1 and
the second pitch P.sub.2.
[0134] The third dents 93 are arranged at the third pitch P.sub.3
around the third central axis C3. The fourth dents 94 are arranged
at the fourth pitch P.sub.4 around the third central axis C3
different from the third pitch P.sub.3. The second pin 65 is housed
in one of the third dents 93 and one of the fourth dents 94,
thereby limiting the relative rotation between the second member 62
and the third member 63. This makes it possible to finely adjust
the position (angle) of the third member 63 relative to the second
member 62 around the third central axis C3 in unit of the
difference .DELTA.P.sub.34 between the third pitch P.sub.3 and the
fourth pitch P.sub.4.
[0135] The distance r.sub.12 between the first central axis C1 and
the second central axis C2 is equal to the distance r.sub.23
between the second central axis C2 and the third central axis C3.
Thus, the third central axis C3 can coincide with the first central
axis C1.
[0136] The difference .DELTA.P.sub.34 between the third pitch
P.sub.3 and the fourth pitch P.sub.4 is a divisor of at least one
of the third pitch P.sub.3 and the fourth pitch P.sub.4. The third
pitch P.sub.3 or the fourth pitch P.sub.4 can be equally divided by
the difference P.sub.34. This makes it possible to adjust the
position (angle) of the third member 63 relative to the second
member 62 over the whole circumference around the third central
axis C3 in unit of the difference .DELTA.P.sub.34.
[0137] At least one of the third pitch P.sub.3 and the fourth pitch
P.sub.4 is set to a divisor of 360 degrees. This setting can
further reduce the numbers of the third dents 93 and the fourth
dents 94 which are arranged to be able to adjust the position
(angle) of the third member 63 relative to the second member 62
over the whole circumference around the third central axis C3 in
unit of the difference .DELTA.P.sub.34. As a result, the third
dents 93 and the fourth dents 94 are easily formed, facilitating
the assembly of the bushing 36.
[0138] The third pitch P.sub.3 is equally divided into n.sub.a
parts by the difference .DELTA.P.sub.34 between the third pitch
P.sub.3 and the fourth pitch P.sub.4, and 360 degrees is equally
divided into n.sub.b parts by the third pitch P.sub.3. When the
difference .DELTA.P.sub.34 is a divisor of 360 degrees, the
combination of the third pitch P.sub.3 and the fourth pitch P.sub.4
satisfies the expression 4. When the difference .DELTA.P.sub.34
differs from a divisor of 360 degrees, the combination of the third
pitch P.sub.3 and the fourth pitch P.sub.4 satisfies the expression
5. The combination of the third pitch P.sub.3 and the fourth pitch
P.sub.4 is the one resulting in a value closest to zero from the
expression 4 or expression 5 among the multiple combinations of the
angles of the third pitch P.sub.3 and the fourth pitch P.sub.4.
Thereby, the position (angle) of the third member 63 relative to
the second member 62 can be properly adjusted over the whole
circumference around the third central axis C3 in unit of the
difference .DELTA.P.sub.34, and the numbers of the third dent 93
and the fourth dents 94 can be reduced. As a result, the third
dents 93 and the fourth dents 94 can be easily formed, facilitating
the assembly of the bushing 36.
[0139] The difference .DELTA.P.sub.12 between the first pitch
P.sub.1 and the second pitch P.sub.2 is a divisor of at least one
of the first pitch P.sub.1 and the second pitch P.sub.2. The first
pitch P.sub.1 or the second pitch P.sub.2 can be equally divided by
the difference .DELTA.P.sub.12. The position (angle) of the second
member 62 relative to the first member 61 around the second central
axis C2 can be adjusted over the whole circumference around the
second central axis C2 in unit of the difference
.DELTA.P.sub.12.
[0140] At least one of the first pitch P.sub.1 and the second pitch
P.sub.2 is set to a divisor of 360 degrees. This setting can reduce
the numbers of the first dents 91 and the second dents 92 which are
arranged to be able to adjust the position (angle) of the second
member 62 relative to the first member 61 around the second central
axis C2 in unit of the difference .DELTA.P.sub.12. As a result, the
first dents 91 and the second dents 92 can be easily formed,
facilitating the assembly of the bushing 36.
[0141] The second pitch P.sub.2 is equally divided into n.sub.c
parts by the difference .DELTA.P.sub.12 between the second pitch
P.sub.2 and the first pitch P.sub.1. 360 degrees is equally divided
into 1/2n.sub.d parts by the second pitch P.sub.2. When the
difference .DELTA.P.sub.12 is a divisor of 360 degrees and the
number of the first dents 91 arranged at the first pitch P.sub.1
around the second central axis C2 is N, the combination of the
first pitch P.sub.1 and the second pitch P.sub.2 satisfies the
expressions 6 and 7. When the difference .DELTA.P.sub.12 differs
from a divisor of 360 degrees, the combination of the first pitch
P.sub.1 and the second pitch P.sub.2 satisfies the expression 9.
This combination of the first pitch P.sub.1 and the second pitch
P.sub.2 is the one resulting in a value closest to zero from the
expression 6 or expression 9 among the multiple combinations.
Thereby, it is made possible to adjust the position (angle) of the
second member 62 relative to the first member 61 around the second
central axis C2 in unit of the difference .DELTA.P.sub.12, and to
reduce the numbers of the first dent 91 and the second dents 92. As
a result, the first dents 91 and the second dents 92 can be easily
formed, facilitating the assembly of the bushing 36.
[0142] The difference .DELTA.P.sub.12 between the first pitch
P.sub.1 and the second pitch P.sub.2 is a divisor of the second
pitch P.sub.2, the second pitch P.sub.2 is a divisor of 360
degrees, and the difference .DELTA.P.sub.12 is a divisor of 360
degrees. When a value obtained by dividing 360 degrees by the
difference .DELTA.P.sub.12 is an odd number, the combination of the
first pitch P.sub.1 and the second pitch P.sub.2 satisfies the
expression 8 and the number of the first dent 91 is one. Thereby,
it is made possible to adjust the position (angle) of the second
member 62 relative to the first member 61 around the second central
axis C2 in unit of the difference .DELTA.P.sub.12, and to reduce
the numbers of the first dent 91 and the second dents 92. As a
result, the first dents 91 and the second dents 92 can be easily
formed, facilitating the assembly of the bushing 36.
Second Embodiment
[0143] The following describes a second embodiment with reference
to FIG. 10. Throughout the following second to fourth embodiments,
the constituting elements having the same functions as the
above-described constituting elements are denoted by the same
reference numerals, and further descriptions thereof may be
omitted. The constituting elements denoted by the same reference
numerals do not necessarily include the same functions and
characteristics, and may include different functions and
characteristics according to the respective embodiments.
[0144] FIG. 10 is a plan view illustrating a part of the bushing 36
according to the second embodiment. As illustrated in FIG. 10, in
the second embodiment, the first pitch P.sub.1 is set to 21
degrees, the second pitch P.sub.2 is set to 20 degrees, the third
pitch P.sub.3 is set to 15 degrees, and the fourth pitch P.sub.4 is
set to 16 degrees.
[0145] The first pitch P.sub.1 and the second pitch P.sub.2 in the
second embodiment satisfy the expressions 6 and 7. In the second
embodiment, however, the numbers of the first dents 91 and the
second dents 92 are larger than those in the first embodiment.
[0146] The third pitch P.sub.3 and the fourth pitch P.sub.4 in the
second embodiment satisfy the expression 4. In the second
embodiment, however, the numbers of the third dents 93 and the
fourth dents 94 are larger than those in the first embodiment.
[0147] In the second embodiment as described above, the combination
of the first pitch P.sub.1 and the second pitch P.sub.2 satisfying
the expressions 6 and 7 may differ from the one resulting in a
value closest to zero from the expressions 6 and 7. The combination
of the third pitch P.sub.3 and the fourth pitch P.sub.4 satisfying
the expression 4 may differ from the one resulting in a value
closest to zero from the expression 4.
[0148] In the air conditioner 10 including the bushing 36 in the
second embodiment, multiple first dents 91 and multiple second
dents 92 oppose each other. This makes it possible to accommodate
two or more first pins 64 in the first dents 91 and the second
dents 92, and to certainly limit the relative rotation between the
first member 61 and the second member 62. Also, multiple third
dents 93 and multiple fourth dents 94 oppose each other. This makes
it possible to accommodate two or more second pins 65 in the third
dents 93 and the fourth dents 94, and to certainly limit the
relative rotation between the second member 62 and the third member
63.
Third Embodiment
[0149] The following describes a third embodiment with reference to
FIG. 11. FIG. 11 is a plan view illustrating a part of the bushing
36 according to the third embodiment. As illustrated in FIG. 11, in
the third embodiment, the first pitch P.sub.1 is set to 38 degrees,
the second pitch P.sub.2 is set to 36 degrees, the third pitch
P.sub.3 is set to 24 degrees, and the fourth pitch P.sub.4 is set
to 26 degrees.
[0150] In the third embodiment, the difference .DELTA.P.sub.34
between the third pitch P.sub.3 and the fourth pitch P.sub.4 is 2
degrees. The third pitch P.sub.3 and the fourth pitch P.sub.4
satisfy the expression 4. As a result, the angle of the third
member 63 with respect to the second member 62 is adjustable in
unit of 2 degrees in the range of 360 degrees.
[0151] In the third embodiment, the difference .DELTA.P.sub.12
between the first pitch P.sub.1 and the second pitch P.sub.2 is 2
degrees. The first pitch P.sub.1 and the second pitch P.sub.2
satisfy the expressions 6 and 7. As a result, the angle of the
second member 62 with respect to the first member 61 is adjustable
in unit of 2 degrees in the range of 360 degrees.
[0152] In the air conditioner 10 including the bushing 36 in the
third embodiment, the difference .DELTA.P.sub.12 between the first
pitch P.sub.1 and the second pitch P.sub.2 is set to 2 degrees, and
the difference .DELTA.P.sub.34 between the third pitch P.sub.3 and
the fourth pitch P.sub.4 is also set to 2 degrees. Thereby, the
relative angles among the first member 61, the second member 62,
and the third member 63 can be adjusted in unit of two degrees.
Fourth Embodiment
[0153] The following describes a fourth embodiment with reference
to FIG. 12. FIG. 12 is a plan view illustrating the bushing 36
according to the fourth embodiment. As illustrated in FIG. 12, in
the fourth embodiment, the first pitch P.sub.1 is set to 48
degrees, the second pitch P.sub.2 is set to 45 degrees, the third
pitch P.sub.3 is set to 30 degrees, and the fourth pitch P.sub.4 is
set to 33 degrees.
[0154] In the fourth embodiment, the difference .DELTA.P.sub.34
between the third pitch P.sub.3 and the fourth pitch P.sub.4 is 3
degrees. The third pitch P.sub.3 and the fourth pitch P.sub.4
satisfy the expression 4. As a result, the angle of the third
member 63 with respect to the second member 62 is adjustable in
unit of 3 degrees in the range of 360 degrees.
[0155] In the fourth embodiment, the difference .DELTA.P.sub.12
between the first pitch P.sub.1 and the second pitch P.sub.2 is 3
degrees. The first pitch P.sub.1 and the second pitch P.sub.2
satisfy the expressions 6 and 7. As a result, the angle of the
second member 62 with respect to the first member 61 is adjustable
in unit of 3 degrees in the range of 360-degree angle.
[0156] In the air conditioner 10 including the bushing 36 in the
fourth embodiment, the difference .DELTA.P.sub.12 between the first
pitch P.sub.1 and the second pitch P.sub.2 is set to 3 degrees and
the difference .DELTA.P.sub.34 between the third pitch P.sub.3 and
the fourth pitch P.sub.4 is set to 3 degrees. Thereby, the relative
angles among the first member 61, the second member 62, and the
third member 63 can be adjusted in unit of 3 degrees.
[0157] According to at least one of the embodiments described
above, a first limiting member is housed in one of first dents
arranged at an interval of a first angular distance and one of
second dents arranged at an interval of a second angular distance
different from the first angular distance around the second central
axis, thereby limiting the relative rotation between the first
member and the second member. This makes it possible to more finely
adjust the position (angle) of the second member relative to the
first member around the second central axis in unit of the
difference between the first angular distance and the second
angular distance.
[0158] While certain embodiments have been described, these
embodiments have been presented by way of example only, and are not
intended to limit the scope of the inventions. Indeed, the novel
embodiments described herein may be embodied in a variety of other
forms; furthermore, various omissions, substitutions and changes in
the form of the embodiments described herein may be made without
departing from the spirit of the inventions. The accompanying
claims and their equivalents are intended to cover such forms or
modifications as would fall within the scope and spirit of the
inventions.
* * * * *