U.S. patent application number 16/128811 was filed with the patent office on 2019-01-17 for tube pump.
This patent application is currently assigned to WELCO CO., LTD.. The applicant listed for this patent is WELCO CO., LTD.. Invention is credited to Yoji MINATODANI.
Application Number | 20190017500 16/128811 |
Document ID | / |
Family ID | 59850971 |
Filed Date | 2019-01-17 |
View All Diagrams
United States Patent
Application |
20190017500 |
Kind Code |
A1 |
MINATODANI; Yoji |
January 17, 2019 |
TUBE PUMP
Abstract
A tube pump includes a base, a columnar inner peripheral
surface, a tube disposed along the inner peripheral surface, a
rotor disposed concentrically with the inner peripheral surface and
supported by the base while squeezing the tube between the rotor
and the inner peripheral surface, and a drive unit having a drive
shaft passing through the base and configured to couple with the
rotor, the base having a cylindrical supporting part configured to
support the rotor and the drive shaft being inserted in a hollow
portion of the supporting part, the tube pump including a bearing
configured to rotatably support the rotor, the rotor having a body
on which a coupling hole configured to accommodate the supporting
part and the bearing is formed and an annular groove extending in a
circumferential direction being formed on an inner peripheral
surface of the body, the bearing fitting in the annular groove.
Inventors: |
MINATODANI; Yoji;
(Fujisawa-shi, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
WELCO CO., LTD. |
Tokyo |
|
JP |
|
|
Assignee: |
WELCO CO., LTD.
Tokyo
JP
|
Family ID: |
59850971 |
Appl. No.: |
16/128811 |
Filed: |
September 12, 2018 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
PCT/JP2017/010859 |
Mar 17, 2017 |
|
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16128811 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
F04C 5/00 20130101; F04B
43/12 20130101; F16D 1/06 20130101; F04B 43/1253 20130101; H02K
7/116 20130101 |
International
Class: |
F04B 43/12 20060101
F04B043/12 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 18, 2016 |
JP |
2016-055549 |
Claims
1. A tube pump, comprising: a base; a columnar inner peripheral
surface disposed at one face side of the base; a tube of which at
least a portion is disposed along the inner peripheral surface; a
rotor disposed concentrically with the inner peripheral surface and
rotatably supported by the base while squeezing the tube between
the rotor and the inner peripheral surface; and a drive unit
attached on an other face side of the base and having a drive shaft
passing through the base and configured to couple with the rotor,
wherein the base has a cylindrical supporting part protruding to
the one face side and configured to support the rotor, wherein the
drive shaft is inserted in a hollow portion of the supporting part,
wherein the tube pump further comprises a bearing put on an outer
periphery of the supporting part and configured to rotatably
support the rotor, wherein the rotor has a substantially
cylindrical body on which a coupling hole configured to accommodate
the supporting part and the bearing is formed, wherein an annular
groove extending in a circumferential direction is formed on an
inner peripheral surface of the body, and wherein the bearing fits
in the annular groove.
2. The tube pump according to claim 1, wherein the bearing is a
sliding bearing rotatably fitted in the annular groove.
3. The tube pump according to claim 1, comprising: a pair of the
bearings; and a cylindrical spacer tucked between the pair of
bearings and placed on the outer periphery of the supporting part,
wherein the pair of bearings and the spacer fit in the annular
groove.
4. The tube pump according to claim 3, wherein the spacer is fixed
to the body of the rotor.
5. The tube pump according to claim 1, comprising a coupling member
configured to couple the drive shaft of the drive unit and the
rotor, wherein a coupling hole in which one end of the coupling
shaft fits is formed at a center of the rotor, and wherein a
fitting hole in which a distal end of the drive shaft fits is
formed on one end of the coupling member.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This is a Continuation-in-Part of International Application
No. PCT/JP2017/010859 filed on Mar. 17, 2017, which claims priority
from Japanese Patent Application No. 2016-055549 filed on Mar. 18,
2016. The entire disclosures of the prior applications are
incorporated herein by reference.
TECHNICAL FIELD
[0002] The present disclosure relates to tube pumps, rotation
restricting parts, shafts and shaft connection structures.
BACKGROUND
[0003] Tube pumps which transport liquid inside an elastic tube
arranged in a circular arc along an inner peripheral surface of a
casing formed in a substantially columnar surface by making a
roller roll along the inner peripheral surface while squeezing the
elastic tube between the inner peripheral surface and the roller
have been conventionally known.
[0004] A conventionally known tube pump includes a rotor and a
drive unit configured to rotationally drive the rotor. Furthermore,
the rotor rotatably supports a plurality of rollers. The tube pump
is configured such that, when the rotor is rotationally driven by
the drive unit, each roller rolls along the inner peripheral
surface.
SUMMARY
[0005] In the above-mentioned tube pump, a restoring force of the
tube squeezed by the rollers acts on the rotor in a radial
direction of the rotary shaft. Furthermore, the rotor is supported
by being coupled to a drive shaft of the drive unit. Therefore, the
restoring force (radial load) of the tube acting on the rotor is
transmitted to the drive shaft of the drive unit. There has been a
problem that the drive unit fails or a service life of the drive
unit shortens due to this radial load.
[0006] Aspects of the present disclosure are advantageous to
provide one or more improved techniques, for a tube pump, which are
capable of suppressing failure of a drive unit and elongating
service life of the drive unit.
[0007] According to aspects of the present disclosure, there is
provided a tube pump including a base, a columnar inner peripheral
surface disposed at one face side of the base, a tube of which at
least a portion is disposed along the inner peripheral surface, a
rotor disposed concentrically with the inner peripheral surface and
rotatably supported by the base while squeezing the tube between
the rotor and the inner peripheral surface, and a drive unit
attached on an other face side of the base and having a drive shaft
passing through the base and configured to couple with the rotor.
The base has a cylindrical supporting part protruding to the one
face side and configured to support the rotor, and the drive shaft
is inserted in a hollow portion of the supporting part. The tube
pump further includes a bearing put on an outer periphery of the
supporting part and configured to rotatably support the rotor. The
rotor has a substantially cylindrical body on which a coupling hole
configured to accommodate the supporting part and the bearing is
formed, and an annular groove extending in a circumferential
direction is formed on an inner peripheral surface of the body. The
bearing fits in the annular groove.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] FIG. 1 is an appearance diagram of a tube pump according to
an embodiment of the present disclosure.
[0009] FIG. 2 is an appearance diagram of the tube pump according
to the embodiment of the present disclosure.
[0010] FIG. 3 is an exploded view of the tube pump according to the
embodiment of the present disclosure.
[0011] FIG. 4 is a perspective side view of a pump unit according
to the embodiment of the present disclosure.
[0012] FIG. 5 is an appearance diagram of a cover according to the
embodiment of the present disclosure.
[0013] FIG. 6 is an exploded view of a rotor according to the
embodiment of the present disclosure.
[0014] FIG. 7 is a side sectional view of a pump unit according to
a variation of the embodiment of the present disclosure.
[0015] FIG. 8 is an appearance diagram of a drive unit according to
the variation of the embodiment of the present disclosure.
[0016] FIG. 9 is an exploded oblique view of the drive unit
according to the variation of the embodiment of the present
disclosure.
[0017] FIG. 10 is an appearance diagram of a rotation restricting
part according to the variation of the embodiment of the present
disclosure.
[0018] FIG. 11 is an appearance diagram of a gear according to the
variation of the embodiment of the present disclosure.
[0019] FIG. 12 is an appearance diagram of a drive unit of a
comparative example.
[0020] FIG. 13 is an exploded oblique view of the drive unit of the
comparative example.
[0021] FIG. 14 is an appearance diagram of a gear of the
comparative example.
DETAILED DESCRIPTION OF EMBODIMENTS
[0022] Hereinafter, embodiment of the present disclosure will be
described with reference to the drawings. Tube pumps according to
the embodiments of the present disclosure which will be described
below are a generic transfusion pumps, and are used for
transporting liquids in cleaning devices, food processing devices,
various types of analyzing instruments, medical instruments and
chemical devices. Also, the tube pumps according to the embodiment
of the present disclosure can be used not only for transporting
liquids but also for transporting gases and other fluids. In the
following description, the same or corresponding numerals are
assigned to the same or corresponding components, and redundant
descriptions will be herein omitted.
[0023] FIG. 1 and FIG. 2 are appearance diagrams of a tube pump 100
according to an embodiment of the present disclosure. FIG. 1 is an
oblique view viewed from a front side of the tube pump 100, and
FIG. 2 is an oblique view viewed from a back side of the tube pump
100. FIG. 3 is an exploded oblique view of the tube pump 100. FIG.
4 is a side sectional view of a pump unit 120 included in the tube
pump 100.
[0024] It is noted that, in the following description, a depth
direction/front rear direction of the tube pump 100 (in FIG. 1, a
direction from the upper right toward the lower left) will be
referred to as an X-axis direction, a width direction/right-left
direction (in FIG. 1, a direction from the bottom toward the top)
will be referred to as a Y-axis direction, and a height
direction/up-down direction (in FIG. 1, a direction from the lower
right toward the upper left) will be referred to as a Z-axis
direction. It is noted that, although FIGS. 1-2 show the tube pump
100 in a horizontally disposed state (a position in which the width
direction of the tube pump 100 is oriented in the vertical
direction), the tube pump 100 can also be installed in a normal
attitude (an attitude in which the height direction of the tube
pump 100 is oriented in the vertical direction) by altering an
orientation of a stay 180 which will be described later.
[0025] As shown in FIG. 1 and FIG. 2, the tube pump 100 includes a
pump unit 120 being a main unit of a pump mechanism, a drive unit
110 configured to drive the pump unit 120, and a stay 180 for
attaching the tube pump 100. The drive unit 110 and the stay 180
are detachably attached to the pump unit 120 with four bolts
112a.
[0026] The pump unit 120 includes a base 130 and a cover 140. A
chassis of the pump unit 120 is configured by the base 130 and the
cover 140. As shown in FIG. 3, a rotor 150 and a tube 160 are
accommodated inside the chassis of the pump unit 120. The tube 160
is formed of an elastomer such as a synthetic rubber and has a
rubber elasticity.
[0027] The drive unit 110 includes a motor 111, a driver 118
configured to supply driving power to the motor 111, and a
reduction gear 112 configured to amplify torque of the motor 111.
By the reduction gear 112, a rotary motion of the motor 111 is
decelerated and the torque of the motor 111 is amplified. A drive
shaft 113 being an output shaft of the reduction gear 112 is
connected the rotor 150, and the torque amplified by the reduction
gear 112 is transmitted to the rotor 150 via the drive shaft
113.
[0028] The stay 180 is a member formed by, for example, processing
a metal sheet such as a stainless steel sheet. The stay 180 has a
substantially rectangular flat plate like main portion 181, a pair
of leg portions 182 formed by perpendicularly bending the metal
sheet backward at both ends of the main portion 181 in a width
direction, and a pair of fixing portions 183 formed by bending the
metal sheet outward in the width direction at a distal end of each
leg portion 182. At a substantially central portion of the main
portion 181, an opening 181a through which the drive shaft 113 of
the drive unit 110 passes and four through holes 181b disposed at
regular intervals around the opening 181a are formed. Through the
through holes 181b, bolts 112a for attaching the drive unit 110 to
the pump unit 120 are inserted. Hereinafter, the opening 181a and
the four through holes 181b will be collectively referred to as a
clearance shape.
[0029] The clearance shape of the stay 180 has four times rotation
symmetry about a center of the opening 181a. Therefore, the stay
180 can be attached to the pump unit 120 even if the stay 180 is
rotated about the center of the opening 181a by 90 degrees each
time. The tube pump 100 can be installed in various attitudes by
changing an attaching orientation of the stay 180 to the pump unit
120.
[0030] The base 130 has a substantially flat plate like main
portion 131, and a substantially flat plate like bottom plate
portion 132 protruding perpendicularly from a lower end portion of
the main portion 131 in the X-axis positive direction. On a back
surface of the main portion 131, the drive unit 110 and the stay
180 are fixed. Also, a circular through hole is formed at the
center of the main portion 131, and a cylindrical portion 131a
protruding perpendicularly from a rim of the through hole is
formed. In the cylindrical portion 131a, the drive shaft 113 of the
drive unit 110 is inserted from the back side. Furthermore, to the
bottom plate portion 132, a pair of U-shaped cutout portions 132a
in which tube joints 161, which will be described later, are to be
inserted is formed.
[0031] On a front surface of the main portion 131, a rib (guide
portion 131b) protruding perpendicularly from the main portion 131
and extending along a U-shaped outer rim is formed. The guide
portion 131b is disposed along an inner side face of a side wall
142 of the cover 140, which will be described later, when the cover
140 is mounted on the base 130.
[0032] FIG. 5 is a diagram of the cover 140 viewed from the back
side. The cover 140 has a substantially flat plate like main
portion 141, and a side wall 142 protruding substantially
perpendicularly from a rim of the main portion 141. The main
portion 141 of the cover 140 is disposed in parallel with the main
portion 131 of the base 130 with the rotor 150 therebetween. The
side wall 142 has a semi-cylindrical upper portion 142a, and a pair
of lower portions 142b extending downwardly from both ends of the
upper portion 142a. The pair of lower portions 142b are
substantially flat plate shaped portions formed in parallel with
each other. The side wall 142 is not provided at a lower end of the
cover 140 (between the pair of lower portions 142b). In other
words, to the side wall 142, a cutout portion 142n is formed at a
lower end portion opposing the upper portion 142a formed in the
semi-cylindrical shape.
[0033] At an end portion of the side wall 142 at the back side, a
flange portion 142c protruding outwardly from the outer periphery
of the side wall 142 (i.e., expanding in diameter) is formed. On an
inner periphery of the flange portion 142c, a pair of guiding
grooves 142d1 (FIG. 5) and one guiding groove 142d2 (FIG. 4) are
formed. The pair of guiding grooves 142d1 are formed at respective
left and right lower end portions of the flange portion 142c. Also,
the guiding groove 142d2 is formed at an upper end portion of the
flange portion 142c. Furthermore, as shown in FIG. 3, at a rim
portion of the main portion 131 of the base 130, a pair of
projections 131c1 and one projection 131c2, protruding
circumferentially, are formed. The pair of projections 131c1 are
formed at both end portions of the main portion 131 in the
left-right direction in forms that extend in the up-down direction.
Also, the projection 131c2 is formed at an upper end portion of the
main portion 131. When the cover 140 is mounted on the base 130,
the pair of projections 131c1 are fitted in the pair of guiding
grooves 142d1, respectively. Furthermore, as shown in FIG. 4, the
projection 131c2 is fitted in the guiding groove 142c2. An inner
diameter of the flange portion 142c at positions where the guiding
grooves 142d1, 142d2 are not formed is designed to be substantially
the same as an outer diameter of the main portion 131 of the base
130 at positions where the projections 131c1, 131c2 are not formed.
Therefore, when the projections 131c1, 131c2 are fitted in
respective guiding grooves 142d1, 142d2, an inner side face of the
flange portion 142c and an end face of the main portion 131 contact
with each other.
[0034] Furthermore, the tube pump 100 of the present embodiment
includes a fixing structure 170 for fixing the cover 140 to the
base 130. The fixing structure 170 of the present embodiment is
configured with screw holes (female screws) 171 formed on the cover
140, through holes 172 formed on the base 130, and bolts 173 for
tightening the cover 140 and the base 130 together. As shown in
FIG. 5 with dotted lines, the screw holes 171 are formed at lower
end portions of a pair of lower portions 142b of the cover 140.
Furthermore, the through holes 172 are formed at positions that
communicate with the screw holes 171 when the cover 140 is mounted
on the base 130, and penetrate through the base 130 in the up-down
direction. The cover 140 is mounted on the base 130 from above such
that the projections 131c1 are inserted in corresponding guide
grooves 142d1. As the bolts 173 inserted in the through holes 172
from below are screwed in the screw holes 171, the cover 140 gets
fixed to the base 130. The rotor 150 and the tube 160 are
accommodated in a special area surrounded by the cover 140 and the
base 130.
[0035] FIG. 6 is an exploded oblique view of the rotor 150. The
rotor 150 includes two disk like frames 151 and 152 forming flange
portions. On a back surface of the frame 151 disposed on the front
side, four bosses 151a and one cylindrical portion 151b, protruding
perpendicularly, are formed. The four bosses 151a are disposed
around a rotary shaft of the rotor 150 at regular intervals (i.e.,
disposed on a columnar surface concentric with the drive shaft
113). On a front surface of the frame 152 disposed on the back
side, four bosses 152a and one cylindrical portion 152b, protruding
perpendicularly, are formed. The four bosses 152a are disposed to
oppose to the four bosses 151a in the X-axis direction. The
cylindrical portion 151b protrudes perpendicularly from a rim of a
through hole provided at the center of the frame 151. Similarly,
the cylindrical portion 152b protrudes perpendicularly from a rim
of a through hole provided at the center of the frame 152. Outer
diameters of the cylindrical portion 151b and the cylindrical
portion 152b are substantially the same, and opposing end faces are
made to abut against each other to form one continuous cylindrical
body 153.
[0036] An inner diameter of the body 153 of the rotor 150 is larger
than an outer diameter of the cylindrical portion 131a of the base
130, and a hollow portion of the body 153 accommodates the
cylindrical portion 131a of the base 130. Also, a pair of annular
bearings 154a, 154b and a cylindrical spacer 155 are disposed
between the body 153 and the cylindrical portion 131a. The bearings
154a, 154b and the spacer 155 are fitted in annular grooves formed
on an inner periphery of the body 153. Furthermore, the spacer 155
are disposed between the bearing 154a and the bearing 154b. The
spacer 155 is used to hold the bearing 154a and the bearing 154b
with a predetermined gap therebetween in the X-axis direction. To
the spacer 155, a screw hole 155a penetrating in a radial direction
of the spacer 155 is formed. A locking screw 155b is screwed in the
screw hole 155a, and one end portion of the locking screw 155b
protrudes from an outer peripheral surface of the spacer 155. On
the body 153, a through hole 153a is formed. The one end portion of
the locking screw protruding from the outer peripheral surface of
the spacer 155 is inserted in the through hole 153a. By this
configuration, displacements of the spacer 155 with respect to the
body 153 of the rotor 150 in an axial direction (X-axis direction,
second direction) and in a circumferential direction are
restricted, and thereby the spacer 155 is fixed to the body
153.
[0037] The bearings 154a and 154b are sliding bearings. The
bearings 154a and 154b are not fixed to the body 153 but are held
to be freely rotatable with respect to the body 153. Furthermore,
the bearing 154a is tucked between a level difference 151d provided
to an inner periphery of the cylindrical portion 151b and the
spacer 155. By this configuration, a displacement of the bearing
154a in an axial direction of the bearing 154a (X-axis direction)
is restricted. Similarly, the bearing 154b is tucked between a
level difference 152d provided to an inner periphery of the
cylindrical portion 152b and the spacer 155. By this configuration,
a displacement of the bearing 154b in an axial direction of the
bearing 154b is restricted. In other words, an annular groove 153g
extending in a circumferential direction and having the level
difference 151d and the level difference 152d are formed on an
inner peripheral surface of the body 153, and the pair of bearings
154a and 154b and the spacer 155 are fitted in this annular groove.
Therefore, the bearing 154a and 154b are held such that only their
rotating movements are permitted. As the bearings 154a and 154b, a
ball bearing in which an inner ring is configured to be freely
rotatable with respect to an outer ring may be used. In this case,
the outer rings of the bearings 154a and 154b are fixed by, for
example, firmly fitting to the inner peripheral surfaces of the
cylindrical portions 151b and 152b.
[0038] The rotor 150 includes a pair of rollers 156a and a pair of
guide rollers 156b. The rollers 156a and the guide rollers 156b are
rotatably supported by corresponding pairs of boss 151a and boss
152a. The pair of rollers 156a are disposed while being arranged in
a radial direction of the rotor 150 with the body 153 therebetween.
The pair of guide rollers 156b are also disposed while being
arranged in a radial direction of the rotor 150 with the body 153
therebetween. The radial direction the pair of rollers 156a are
arranged and the radial direction the pair of guide rollers 156b
are arranged are orthogonal to each other. That is, the rollers
156a and the guide rollers 156b are alternately disposed in a
rotating direction of the rotor 150 with 90 degrees intervals.
[0039] A portion of the roller 156a protrudes to an outer
peripheral side with respect to the frames 151, 152. The roller
156a has a substantially cylindrical shape, and the tube 160 is
squeezed between an outer peripheral surface of the roller 156a and
an inner peripheral surface 142e of the cover 140. The guide roller
156b (FIG. 6) has an outer peripheral surface having a shape of a
hyperboloid of one sheet which a central portion in an axial
direction of the guide roller 156b is constricted such that the
guide roller 156b conforms to a cylindrical outer peripheral
surface of the tube 160 in a non-squeezed state. A position of the
tube 160 in the X-axis direction is kept at a central portion of
the guide roller 156b in the X-axis direction by the tube 160
contacting the outer peripheral surface of the guide roller 156b.
By this configuration, the tube 160 can be prevented from being
damaged by being scratched by the main portion 131 of the base 130,
the main portion 141 of the cover 140, the frame 151 or the frame
152. Furthermore, vibrations of the tube 160 with respect to the
rotary shaft of the rotor 150 in an axial direction and a radial
direction of the rotary shaft of the rotor 150 that occurs during
operation can also be suppressed. It is noted that the rotor 150
may include four cylindrical rollers 156a in place of the pair of
rollers 156a and the pair of guide rollers 156b.
[0040] As shown in FIG. 4, the tube 160 is nipped between the
roller 156a and the inner peripheral surface 142e of the side wall
142 of the cover 140, and is squeezed so that an inner peripheral
surface of the tube 160 is crushed. At a squeezed position
(collapsed part) of the tube 160, a hollow portion of the tube 160
is closed. As the roller 156a rolls along the inner peripheral
surface 142e of the side wall 142, the collapsed part of the tube
160 moves along with the roller 156a, and thereby liquid inside the
tube 160 moves in a rotating direction of the rotor 150 (a turning
direction of the roller 156a).
[0041] As shown in FIG. 4 and FIG. 6, a coupling hole 151e is
formed inside the cylindrical portion 151b of the frame 151. The
rotor 150 and a coupling shaft 157 are coupled by fitting one end
of the coupling shaft 157 on the front side in the coupling hole
151e. On an inner peripheral surface of the coupling hole 151e, a
plurality of protruding portions 151f extending in the X-axis
direction are formed at constant intervals in a circumferential
direction. Also, the one end of the coupling shaft 157 on the front
side is a spline shaft which a plurality of grooves 157a extending
in the X-axis direction are formed on an outer peripheral surface
at constant intervals in a circumferential direction. The coupling
shaft 157 and the coupling hole 151e are coupled by a spline joint
by fitting the protruding portions 151f of the coupling hole 151e
in respective grooves 157a of the coupling shaft 157. The coupling
shaft 157 is a substantially cylindrical member. In a hollow
portion (fitting hole) of the coupling shaft 157, the drive shaft
113 is inserted. On an inner peripheral surface of the coupling
shaft 157, a groove 157b extending in the X-axis direction is
formed.
[0042] Next, methods for attaching the rotor 150 and the tube 160
to the tube pump 100 will be described. Attachments of the rotor
150 and the tube 160 are performed in a state where the cover 140
is detached from the base 130 and the drive unit 110 is attached to
the base 130. In this state, the drive shaft 113 is inserted in a
hollow portion of the cylindrical portion 131a of the base 130. As
the rotor 150 is attached to the front side (X-axis positive
direction side) of the base 130, the cylindrical portion 131a of
the base 130 gets inserted in the bearings 154a and 154b of the
rotor 150, and the cylindrical portion 131a and the bearings 154a
and 154b slidably fit. By this configuration, the rotor 150 is
supported rotatably with respect to the base 130.
[0043] Also, as the rotor 150 is attached to the base 130, the
coupling shaft 157 of the rotor 150 couples with the drive shaft
113. Specifically, on an outer peripheral surface of the drive
shaft 113 (FIG. 3), a key 114P extending in the X-axis direction is
provided. The drive shaft 113 couples with the coupling shaft 157
as the drive shaft 113 is inserted in the coupling shaft 157 and
the key 114P of the drive shaft 113 is accommodated in the groove
157b of the coupling shaft 157. Furthermore, since the coupling
shaft 157 is coupled to the frame 151 of the rotor 150, a rotary
motion of the drive shaft 113 is transmitted to the rotor 150 via
the coupling shaft 157.
[0044] After the rotor 150 is coupled to the drive shaft 113, the
tube 160 is put on an outer periphery of the rotor 150 to form a U
shape. As shown in FIG. 3, a pair of tube connectors 161 are
attached at both ends of the tube 160. On a back surface of each
tube connector 161, a guiding groove 161a is formed. Each tube
connector 161 is inserted to the cutout portion 132a of the bottom
plate portion 132 of the base 130. Each tube connector 161 is held
on the base 130 by a rim portion of the cutout portion 132a of the
bottom plate portion 132 of the base 130 being inserted in the
guiding groove 161a. By this configuration, displacements of the
tube 160 in the up-down direction and the left-right direction are
prevented and thereby the tube 160 is prevented from falling off
the rotor 150.
[0045] After the tube 160 is attached, the cover 140 is attached to
the base 130. As indicated in FIG. 3 with an arrow A, the cover 140
is attached to the base 130 from above.
[0046] The pump unit 120 has a guiding structure configured to
guide the cover 140 to a predetermined position with respect to the
base 130. The guiding structure includes a second direction
displacement restricting structure for restricting displacement of
the cover 140 with respect to the base 130 in the front-rear
direction (X-axis direction, second direction), and a third
direction displacement restricting structure for restricting
displacement of the cover 140 with respect to the base 130 in the
right-left direction (Y-axis direction, third direction).
[0047] In attaching the cover 140 to the base 130, the cover 140 is
positioned with respect to the base 130 in the X-axis direction by
making an end face 142f (FIG. 5) on a back side of the side wall
142 of the cover 140 to abut the rim portion (a portion outside the
guide portion 131b) of the main portion 131 of the base 130 from
the front side. Also, as the projection 131c1 of the base 130 is
inserted in the guiding groove 142d1 of the cover 140, the
projection 131c1 gets nipped between a pair of opposing side walls
of the guiding groove 142d1 from both sides in the second direction
(X-axis direction), and therefore displacement of the cover 140
with respect to the base 130 in the second direction is restricted.
That is, a set of the projection 131c1 of the base 130 and the
guiding groove 142d1 of the cover 140 functions as the second
direction displacement restricting structure.
[0048] Also, rattling of the cover 140 within a plane perpendicular
to the X-axis direction can be prevented by the inner side face of
the flange portion 142c of the cover 140 and an end face of the rim
portion of the main portion 131 of the base 130 contacting with
each other. Specifically, displacement of the cover 140 with
respect to the base 130 in the third direction (Y-axis direction)
is restricted when the main portion 131 of the U-shaped base 130 is
inserted to the flange portion 142c of the U-shaped cover 140.
Also, displacement of the cover 140 with respect to the base 130
further downward (Z-axis direction, first direction) is restricted
when the main portion 131 is inserted up to a deepest part of the
flange portion 142c and an upper end face of the base 130 contacts
an upper end portion of an inner peripheral surface of the flange
portion 142c. That is, a set of the flange portion 142c of the
cover 140 and the main portion 131 of the base 130 functions as the
third direction displacement restricting structure and the first
direction displacement restricting structure.
[0049] Also, in attaching the cover 140 to the base 130, the cover
140 is guided and positioned to be mounted at a predetermined
position in two directions perpendicular to the rotary shaft of the
rotor 150 (Y-axis direction and Z-axis direction) by the inner side
face of the side wall 142 of the cover 140 and an outer side face
of the guide portion 131b of the base 130 contacting with each
other. That is, a set of the side wall 142 of the cover 140 and the
guide portion 131b of the base 130 functions as the third direction
displacement restricting structure and the first direction
displacement restricting structure too.
[0050] Also, while attaching the cover 140 to the base 130, the
rotor 150 and the tube 160 enters in the cover 140 from below. A
width in the right-left direction of the cutout portion 142n formed
at the lower end portion of the cover 140 is set larger than an
outer diameter of the rotor 150. Also, the width of the cutout
portion 142n is set to a size which the rotor 150 and the tube 160
put on the outer periphery of the rotor 150 can pass through.
Therefore, the cover 140 can be attached to the base 130 from above
while accommodating the rotor 150 inside the cover 140 through the
cutout portion 142n. Furthermore, when mounting the cover 140 to
the base 130, the tube 160 gets nipped between the rollers 156a of
the rotor 150 and the inner peripheral surface 142e of the cover
140. After being nipped between the rollers 156a and the inner
peripheral surface 142e, the tube 160 enters in the cover 140 while
being squeezed.
[0051] After the cover 140 is disposed at the predetermined
position with respect to the base 130 while accommodating the rotor
150 and the tube 160 therein, the cover 140 and the base 130 are
fixed to each other by two bolts 173. It is noted that, since the
screw holes 171 extend in the up-down direction (cover mounting
direction; first direction), the cover 140 and the base 130 are
tightened together in the up-down direction by the bolts 173.
Therefore, even if an upward force is acting on the cover 140 due
to the restoring force of the squeezed tube 160, the cover 140 can
be displaced to the predetermined position while resisting to the
restoring force of the tube 160 by tightening forces of the bolts
173 acting downward and can be firmly fixed to the base 130. On the
other hand, the only actions needed to remove the cover 140 from
the base 130 is removing the two bolts 173 and pulling the cover
upward.
[0052] As described above, in the present embodiment, the rotor 150
and the tube 160 are accommodated inside the cover 140 by mounting
the cover 140 to the base 130 from above in the state where the
rotor 150 and the tube 160 are mounted on the base 130.
Furthermore, while mounting the cover 140, the tube 160 receives a
downward force from the cover 140 but does not receive forces in
the front-rear directions. Therefore, the tube 160 is prevented
from displacing in an axial direction of the rotor 150 and falling
off the rotor 150 while mounting the cover 140.
[0053] Also, after the cover 140 is mounted on the base 130, the
position of the cover 140 is fixed by the fixing structure 170
(screw holes 171, through holes 172 and bolts 173). Therefore, the
cover 140 will not displace from the predetermined position with
respect to the base 130 by external forces or the force from the
tube 160.
[0054] Also, in the present embodiment, the tube 160 is held on the
base 130 by attaching the tube connector 161 of the tube 160 to the
cutout portion 132a of the base 130. In this state, displacements
of the tube 160 in the up-down direction and the right-left
direction are restricted by the guiding groove 161a of the holder
161 fitting to the rim portion of the cutout portion 132a of the
bottom plate portion 132, and thereby the tube 160 is prevented
from falling off the rotor 150. Furthermore, since the tube 160 is
held on the base 130 even in a state where the cover 140 is not
attached to the base 130, there is no need to hold the tube 160 to
place the tube 160 at an appropriate position while attaching the
cover 140 to the base 130. Additionally, since the tube 160 gets
nipped between the rollers 156a of the rotor 150 and the inner
peripheral surface 142e of the cover 140 and then enters in the
cover 140 while being squeezed, there is no need to keep the tube
160 in a squeezed state while attaching the cover 140 to the base
130. Therefore, the tube pump 100 is easy to assemble.
[0055] it is noted that a conventionally known tube pump has a base
and a cover, and a tube and a rotor are accommodated inside the
cover. The rotor has a plurality of rollers, and gaps between the
rollers and an inner peripheral surface of the cover are set to be
narrow such that the tube can be squeezed. Also, a drive unit is
mounted on a side of the base opposite to the cover, and a drive
shaft of the drive unit is coupled to the rotor. The cover is
detachable from and attachable to the base, thereby making it
possible to easily perform maintenances of the tube and the
rotor.
[0056] However, in such known tube pump, the cover covers the rotor
around which the tube is wound from a direction of the rotary shaft
and is mounted on the base. Therefore, there has been a problem
that, while mounting the cover on the base, the tube gets pressed
by the cover in the direction of the rotary shaft and drops off the
rotor, thereby making it difficult to properly place the tube
between the rotor and the inner peripheral surface of the
cover.
[0057] Therefore, aspects of the present disclosure are
advantageous to provide one or more improved techniques, for a tube
pump, which provide a tube pump which can be assembled easily.
[0058] Also, in the present embodiment, the rotor 150 is rotatably
supported on the base 130 by the bearings 154a and 154b fitting in
the cylindrical portion 131a of the base 130. Furthermore, the
drive unit 110 transmits the rotary motion to the rotor 150
supported on the base 130 via the drive shaft 113. By providing the
structure for supporting the rotor 150 and the structure for
transmitting the rotary motion to the rotor 150 separately as
described above, loads acting on the drive unit 110 can be
suppressed.
[0059] Specifically, as the rollers 156a that the rotor 150 has
squeeze the tube 160 between the inner peripheral surface 142e of
the cover 140, the rotor 150 receives forces acting in radially
inward directions (radial loads) due to the restoring forces of the
tube 160 for recovering from the squeezed state to the original
cylindrical state. Furthermore, since the rollers 156a turn around
the rotary shaft of the rotor 150, the radial loads also rotate.
For example, if the pair of rollers 156a are symmetrically disposed
in the right-left direction with respect to the rotary shaft of the
rotor 150 (i.e., the pair of rollers 156a are arranged in the
Y-axis direction), since every rollers 156a squeezes the tube 160
to about the same degree, two radial loads the rotor 150 receives
from the tube 160 will be cancelled. On the other hand, if one of
the pair of rollers 156a is positioned above the rotary shaft and
the other is positioned below the rotary shaft, since the pump unit
120 has a vertically asymmetrical shape (specifically, no side wall
142 is formed on the lower half), the radial loads acting on the
rotor 150 will not be cancelled and thus remain. Furthermore, the
radial loads that are not cancelled and remained vary in magnitudes
and directions in accordance with a rotating position (phase) of
the rotor 150. Assuming that the varying radial loads act on the
drive shaft 113, the drive unit 110 may fail or a service life of
the drive unit 110 may be shortened.
[0060] However, in the present embodiment, the radial loads acting
on the rotor 150 act on the base 130 via the bearings 154a, 154b
and the cylindrical portion 131a on which the bearings 154a and
154b are put. Accordingly, the radial loads do not act on the drive
shaft 113 and therefore occurrence of problems such as the failure
of the drive unit 110 can be suppressed.
[0061] (Variation)
[0062] Next, a variation of the above-described embodiment will be
described. This variation is a tube pump in which the drive shaft
113 of a drive unit 110A and a rotor 150A are coupled via a
rotation restricting part 114 and a gear 115, which will be
described later, in place of the coupling shaft 157 of the
above-described embodiment.
[0063] FIG. 7 is a side sectional view of a pump unit 120A of the
present variation. FIG. 8 and FIG. 9 are an appearance diagram and
an exploded oblique view of the drive unit 110A of the present
variation, respectively.
[0064] As shown in FIG. 8 and FIG. 9, at a distal end of the drive
shaft 113 of the drive unit 110A, the rotation restricting part 114
and the gear 115 are attached by a bolt 116.
[0065] FIG. 10 is an appearance diagram of the rotation restricting
part 114 (an oblique view viewed from the front). The rotation
restricting part 114 is a member formed by, for example, processing
a metal sheet such as a stainless steel sheet. The rotation
restricting part 114 has a substantially disk-shaped base portion
114b to which a through hole 114c is formed at a central portion,
and a substantially strip-shaped (rectangular plate-shaped) leg
portion 114a extending from one end of the base portion 114b.
[0066] The substantially disk-shaped base portion 114b has a
substantially D shape formed by cutting the disk shape with a plane
perpendicular to a plate face of the disk shape (D-cut) at a
position away from the through hole 114c.
[0067] The leg portion 114a protrudes from a central portion of the
D-cut end face of the base portion 114b, is bent at right angles
and then extends in a direction perpendicular to the plate surface
of the base portion 114b. As shown in FIG. 8, the leg portion 114a
fits in a key groove 113a (FIG. 9) formed on the drive shaft 113
and restricts rotation of the rotation restricting part 114 with
respect to the drive shaft 113 about a rotation center axis of the
drive shaft 113.
[0068] Also, to the base portion 114b, a columnar protruding
portion 114d protruding in a direction opposite to the direction
the leg portion 114a extends is formed. The protruding portion 114d
is formed, for example, by a half punch press (or a half piercing)
process.
[0069] FIG. 11 is an appearance diagram of the gear 115 (an oblique
view viewed from the back). To the gear 115, a through hole 115c is
formed concentrically with a rotation center axis of the gear 115.
Also, on a back surface of the gear 115, a columnar depressed
portion 115d is formed. The protruding portion 114d formed to the
base portion 114b of the rotation restricting part 114 fits in the
depressed portion 115d and restricts rotation of the gear 115 about
the rotation center axis with respect to the rotation restricting
part 114. That is, by the fitting of the leg portion 114a of the
rotation restricting part 114 in the key groove 113a of the drive
shaft 113 and the fitting of the protruding portion 114d of the
rotation restricting part 114 in the depressed portion 115d of the
gear 115, the rotation of the gear 115 about the rotation center
axis with respect to the drive shaft 113 is restricted, and thereby
the gear 115 always rotates integrally with the drive shaft
113.
[0070] The gear 115 and the rotation restricting part 114 are fixed
to the drive shaft 113 by inserting an axis of the bolt 116 in the
through hole 115c of the gear 115 and the through hole 114c of the
rotation restricting part 114 and then screwing the axis of the
bolt 116 in a screw hole (female screw) 113c formed at a distal end
portion of the drive shaft 113.
Comparative Example
[0071] Hereinafter, a comparative example will be used to explain
effects that can be obtained from the configuration of the
above-described variation. FIG. 12 and FIG. 13 are an appearance
diagram and an exploded oblique view of a drive unit 110P being a
comparative example, respectively. FIG. 14 is an appearance diagram
(oblique view viewed from the back) of a gear 115P of the
comparative example. This comparative example is a general
configuration example which connects a gear to a drive shaft by
using a key.
[0072] The gear 115P has a tubular portion 115Pf on which no tooth
115Pe (FIG. 14) is formed. To this tubular portion 115Pf, a hole
115Ph to which the drive shaft 113 is to be inserted is formed. On
a peripheral surface of the hole 115Ph, a key groove 115Pd, having
the same groove width as the key groove 113a of the drive shaft
113, is formed. Rotation of the gear 115P with respect to the drive
shaft 113 is restricted by fitting a key 114P (FIG. 13) both in the
key groove 113a of the drive shaft 113 and the key groove 115Pd of
the gear 115P, and thereby the gear 115P always rotates integrally
with the drive shaft 113. Also, to the tubular portion 115Pf, a
screw hole (female screw) 115Pg extending in a radial direction is
formed. The drive shaft 113, the key 114P and the gear 115P are
integrated by screwing a locking screw 117P (FIG. 13) into the
screw hole 115Pg in a state where the key 114P and the drive shaft
113 are inserted in the hole 115Ph and firmly tightening the key
114P and the drive shaft 113 together. Further, the gear 115P is
securely fixed to the drive shaft 113 by screwing the bolt 116 in
the screw hole 113c formed at the distal end portion of the drive
shaft 113 via the through hole 115Pc of the gear 115P.
[0073] (Comparison Between Variation and Comparative Example)
[0074] When the above-described variation and comparative example
are compared, since the comparative example has the configuration
in which the drive shaft 113 (and the key 114P) fits in the hole
115Ph (and the key groove 115Pd) of the gear 115P, an outer
diameter of the gear 115P is larger than an outer diameter of the
drive shaft 113. In contrast, in the variation, since there is no
need to insert the drive shaft 113 and the key 114P into the gear
115, it is possible to make a diameter of the gear 115 smaller than
that in the comparative example (e.g., up to a diameter
substantially equal to or smaller than that of the drive shaft
113).
[0075] Also, in the variation, since there is no need to insert the
drive shaft 113 and the key 114P into the gear 115, there is no
need to provide the tubular portion 115Pf. As a result, it becomes
possible to make an overall length of the gear 115 shorter than
that of the comparative example.
[0076] Also, in the comparative example, it is necessary to provide
the key groove 115Pd that engages with the key 114P, but since
processing of the key groove 115Pd being an inner groove is
complicated, processing cost is relatively high. In contrast, in
the variation, the rotation restriction of the gear 115 is realized
by the engagement of the depressed portion 115d and the protruding
portion 114d which are easy to process. Furthermore, the rotation
restricting part 114 can be manufactured inexpensively by sheet
metal processing.
[0077] As described above, according to the configuration of the
above-described variation, it becomes possible to downsize the gear
and to attach the gear to the drive shaft with lower cost as
compared to the comparative example. That is, aspects of the
present disclosure provides a shaft connection structure which does
not need to provide an inner groove having relatively high
processing cost and which is easy to reduce its diameter.
[0078] It is noted that the coupling shaft 157 of the
above-described embodiment is a member that corresponds to the gear
115P of the comparative example. That is, in the variation, by the
adoption of the gear 115 and the rotation restricting part 114 in
place of the coupling shaft 157, it is made possible to downsize
the gear 115, while at the same time eliminate the need of the
coupling shaft 157 which has a relatively high processing cost, and
thereby cost reduction is realized. It is noted that, in the
variation, the gear 115 is downsized but the drive shaft 113 is
thickened to strengthen torsional rigidity of the drive shaft
113.
[0079] The above description is directed to the embodiment of the
present disclosure. However, the present disclosure is not limited
to the configurations of the above-described embodiment, but are
capable of various modifications within the scope of the technical
concept. For example, appropriate combinations of at least a part
of one or more technical configurations of the embodiment
explicitly illustrated in this specification and well-known
technical configurations may be also included in the embodiment of
this disclosure.
[0080] For example, in the above-described embodiment, the coupling
hole 151e of the rotor 150 and the drive shaft 113 of the drive
unit 110 are coupled by the coupling shaft 157, but the present
disclosure is not limited to this configuration. For example, in
place of using the coupling shaft 157, the drive shaft 113 may be
directly coupled to the coupling hole 151e. In this case, for
example, spline grooves that fit to the protruding portions 151f of
the coupling hole 151e are formed on the distal end portion of the
drive shaft 113. Alternatively, the frame 152 and the coupling
shaft 157 may be integrally formed.
[0081] In the above-described embodiment, a portion of the roller
156a protrudes to an outer peripheral side with respect to the
frames 151, 152, but the present disclosure is not limited to this
configuration. The entire roller 156a may be disposed slightly to
an inner peripheral side with respect to outer peripheral edges of
the frames 151, 152.
[0082] In the above-described embodiment, the rotor 150 configured
to rotatably support a plurality of rollers, but the present
disclosure is not limited to this configuration. For example, a
configuration in which a roller having an eccentric rotary shaft is
used in place of the rotor 150 is also within the scope of the
present disclosure.
[0083] In the above-described embodiment, the screw holes 171, the
through holes 172 and the bolts 173 are used as the fixing
structure 170 for fixing the cover 140 to the base 130 and the
cover 140 is screwed to the base 130, but the present disclosure is
not limited to this configuration. It is sufficient that the fixing
structure 170 can be switched between a fixed state in which the
displacement of the cover 140 with respect to the base 130 in the
up-down direction is restricted and a state where the fixing is
released, and the method therefor is not limited to screwing.
[0084] In the above-described embodiment, resins are used as
materials for the main structural members of the tube pump 100
(e.g., the base 130, the cover 140 and the rotor 150), but other
types of structure materials such as aluminum alloys or magnesium
alloys may be used.
[0085] In the above-described variation, the through hole 114c for
inserting the bolt 116 is formed to the rotation restricting part
114, but a cutout or a groove hole having an open end may be
provided in place of the through hole 114c.
[0086] In the above-described variation, the leg portion 114a is
formed in the rectangular plate shape, but the leg portion 114a
having other shape may be provided. For example, a wedge-shaped leg
portion that gradually gets thinner as it approaches a distal end,
like a sloping key, may be provided.
[0087] In the above-described variation, the protruding portion
114d is provided to the rotation restricting part 114 and the
depressed portion 115d is provided to the gear 115. However,
conversely, the depressed portion may be provided to the rotation
restricting part and the protruding portion may be provided to the
gear.
[0088] In the above-described variation, one protruding portion
114d and one depressed portion 115d are provided, but a plurality
of depressed portions and protruding portions may be provided. In
this case, the depressed portions (protruding portions) may be
formed around a rotation center axis of the rotation restricting
part (or the gear) at constant intervals.
[0089] Both the depressed portion and the protruding portion may be
provided to the rotation restricting part and the gear,
respectively. Also, in the above-described embodiment, the
protruding portion 114d and the depressed portion 115d are formed
in columnar shapes, but they may have other shapes provided that
they are shapes that mutually fit. For example, the depressed
portion may be a linearly extending key groove (e.g., a rectangular
groove, a V-shaped groove or a U-shaped groove), and may be formed
in a shape that fits to the protruding portion.
[0090] Hereinabove, the illustrative embodiment according to
aspects of the present disclosure has been described. The present
disclosure can be practiced by employing conventional materials,
methodology and equipment. Accordingly, the details of such
materials, equipment and methodology are not set forth herein in
detail. In the previous descriptions, numerous specific details are
set forth, such as specific materials, structures, chemicals,
processes, etc., in order to provide a thorough understanding of
the present disclosure. However, it should be recognized that the
present disclosure can be practiced without reapportioning to the
details specifically set forth. In other instances, well known
processing structures have not been described in detail, in order
not to unnecessarily obscure the present disclosure.
* * * * *