U.S. patent application number 10/627521 was filed with the patent office on 2004-10-14 for tire pressure holding system, tired wheel and valve unit for use with vehicle and tire.
This patent application is currently assigned to Pacific Industrial Co., Ltd.. Invention is credited to Kayukawa, Hisashi, Yamada, Koji.
Application Number | 20040202546 10/627521 |
Document ID | / |
Family ID | 33127866 |
Filed Date | 2004-10-14 |
United States Patent
Application |
20040202546 |
Kind Code |
A1 |
Kayukawa, Hisashi ; et
al. |
October 14, 2004 |
Tire pressure holding system, tired wheel and valve unit for use
with vehicle and tire
Abstract
A tire pressure holding system for a vehicle includes a pump
mounted in the center of a wheel for discharging compressed air in
synchronization with revolution of the wheel, the pump including a
discharge section from which the compressed air is discharged, a
conduit connected to the interior of the tire and the discharge
section of the pump, a check valve mounted in the conduit for
preventing the air in the interior of the tire from flowing to the
pump side, and a release valve mounted in the conduit for releasing
the compressed air from the pump outside when an internal pressure
is at or above a predetermined value in a section of the interior
of the conduit between the check valve and the pump.
Inventors: |
Kayukawa, Hisashi;
(Gifu-ken, JP) ; Yamada, Koji; (Gifu-ken,
JP) |
Correspondence
Address: |
AKIN GUMP STRAUSS HAUER & FELD L.L.P.
ONE COMMERCE SQUARE
2005 MARKET STREET, SUITE 2200
PHILADELPHIA
PA
19103-7013
US
|
Assignee: |
Pacific Industrial Co.,
Ltd.
INOUE Rubber Co., Ltd.
|
Family ID: |
33127866 |
Appl. No.: |
10/627521 |
Filed: |
July 25, 2003 |
Current U.S.
Class: |
417/36 |
Current CPC
Class: |
F04B 33/005 20130101;
B60C 23/127 20200501; F04B 49/035 20130101 |
Class at
Publication: |
417/036 |
International
Class: |
F04B 049/00 |
Foreign Application Data
Date |
Code |
Application Number |
Apr 9, 2003 |
JP |
2003-105536 |
Claims
We claim:
1. A tire pressure holding system for a vehicle having at least a
wheel and a tire mounted around the wheel, the tire having an
interior, the system comprising: a pump provided in a center of the
wheel for discharging compressed air in synchronization with
revolution of the wheel, the pump including a discharge section
from which the compressed air is discharged; a conduit connected to
the interior of the tire and the discharge section of the pump; a
check valve provided in the conduit for preventing the air in the
interior of the tire from flowing to the pump side; and a release
valve provided in the conduit for releasing the compressed air from
the pump outside when an internal pressure is at or above a
predetermined value in a section of the interior of the conduit
between the check valve and the pump.
2. A system according to claim 1, wherein the vehicle comprises a
body and an axle fixed to the body, and the pump includes a rotary
block fixed to the wheel and a driving mechanism connected between
the axle of the vehicle and the rotary block, and the driving
mechanism is actuated by relative rotation between the axle and the
rotary block, thereby producing compressed air.
3. A system according to claim 1, wherein the vehicle comprises a
body and an axle fixed to the body, and the pump includes a rotary
block fixed to the wheel and a coherent mechanism which is actuated
by relative rotation between the axle and the rotary block thereby
to produce compressed air.
4. A system according to claim 1, wherein the vehicle comprises a
body and an axle fixed to the body, and the pump includes a rotary
block fixed to the wheel and a slider crank mechanism which
includes a slider and is actuated by relative rotation between the
axle and the rotary block, and the rotary block includes a cylinder
in which the slider of the slider crank mechanism is direct moved
thereby to serve as a piston so that compressed air is
produced.
5. A system according to claim 1, wherein the check valve and the
release valve are linked with each other so that when either one of
the check valve and the release valve is opened, the other is
closed.
6. A system according to claim 2, wherein the check valve and the
release valve are linked with each other so that when either one of
the check valve and the release valve is opened, the other is
closed.
7. A system according to claim 3, wherein the check valve and the
release valve are linked with each other so that when either one of
the check valve and the release valve is opened, the other is
closed.
8. A system according to claim 4, wherein the check valve and the
release valve are linked with each other so that when either one of
the check valve and the release valve is opened, the other is
closed.
9. A system according to claim 1, wherein the conduit includes an
outlet of the compressed air formed in the pump, a stem fixed to an
outer circumferential edge of the wheel and having a space capable
of communicating with the interior of the tire, and a pipe
connecting each of the outlet and the stem to the other, and the
check valve is fixed to the stem thereby to serve as a tire valve
unit.
10. A system according to claim 2, wherein the conduit includes an
outlet of the compressed air formed in the pump, a stem fixed to an
outer circumferential edge of the wheel and having a space capable
of communicating with the interior of the tire, and a pipe
connecting each of the outlet and the stem to the other, and the
check valve is fixed to the stem thereby to serve as a tire valve
unit.
11. A system according to claim 3, wherein the conduit includes an
outlet of the compressed air formed in the pump, a stem fixed to an
outer circumferential edge of the wheel and having a space capable
of communicating with the interior of the tire, and a pipe
connecting each of the outlet and the stem to the other, and the
check valve is fixed to the stem thereby to serve as a tire valve
unit.
12. A system according to claim 4, wherein the conduit includes an
outlet of the compressed air formed in the pump, a stem fixed to an
outer circumferential edge of the wheel and having a space capable
of communicating with the interior of the tire, and a pipe
connecting each of the outlet and the stem to the other, and the
check valve is fixed to the stem thereby to serve as a tire valve
unit.
13. A system according to claim 5, wherein the conduit includes an
outlet of the compressed air formed in the pump, a stem fixed to an
outer circumferential edge of the wheel and having a space capable
of communicating with the interior of the tire, and a pipe
connecting each of the outlet and the stem to the other, and the
check valve is fixed to the stem thereby to serve as a tire valve
unit.
14. A system according to claim 6, wherein the conduit includes an
outlet of the compressed air formed in the pump, a stem fixed to an
outer circumferential edge of the wheel and having a space capable
of communicating with the interior of the tire, and a pipe
connecting each of the outlet and the stem to the other, and the
check valve is fixed to the stem thereby to serve as a tire valve
unit.
15. A system according to claim 7, wherein the conduit includes an
outlet of the compressed air formed in the pump, a stem fixed to an
outer circumferential edge of the wheel and having a space capable
of communicating with the interior of the tire, and a pipe
connecting each of the outlet and the stem to the other, and the
check valve is fixed to the stem thereby to serve as a tire valve
unit.
16. A system according to claim 8, wherein the conduit includes an
outlet of the compressed air formed in the pump, a stem fixed to an
outer circumferential edge of the wheel and having a space capable
of communicating with the interior of the tire, and a pipe
connecting each of the outlet and the stem to the other, and the
check valve is fixed to the stem thereby to serve as a tire valve
unit.
17. A system according to claim 1, wherein the release valve is
fixed to the pump.
18. A system according to claim 9, wherein the release valve is
fixed to the tire valve unit.
19. A system according to claim 18, wherein the check valve
includes a valve core further including a cylindrical member having
an open end, a shaft extending through the cylindrical member and
having an end, a check valve lid fixed to the end of the shaft and
a check valve urger which urges the lid so that the end of the
cylindrical member is closed, the valve core being accommodated in
the stem with the check valve lid being disposed at the tire side,
and the release valve includes a communicating passage providing
communication between the interior of the conduit and the outside,
a release valve lid direct moved between a first position where the
communicating passage is closed by the lid and a second position
where the communicating passage is opened by the lid, and a release
valve urger which urges the release valve lid toward the first
position, and the check valve and the release valve are associated
with each other so that when either one of the check valve and the
release valve is opened, the other is closed.
20. A system according to claim 18, further comprising an
intermediate valve provided between the release valve and the check
valve in the conduit, wherein the intermediate valve includes a
shaft direct moved in the conduit, a generally disc-shaped sealing
member fitted with an outer circumferential face of the shaft and
having an outer edge curved so as to be pushed out toward the check
valve, the sealing member being adhered closely to a
circumferential face of the conduit, and a limiting plate placed on
the sealing member and limiting elastic deformation of the sealing
member in the direction opposite to the check valve and allowing
the sealing member to elastically deform toward the check
valve.
21. A system according to claim 20, wherein the intermediate valve
is moved toward the check valve when the sealing member is
subjected to the compressed air from the pump, thereby pressing the
check valve so as to open the check valve.
22. A system according to claim 20, wherein the conduit includes an
external pump mount communicating with a space between the release
valve and the check valve, the system further comprising an
external pump discrete from the vehicle and detachably attached to
the external pump mount.
23. A tired wheel comprising a tire pressure holding system for a
vehicle having at least a wheel and a tire mounted around the
wheel, the tire having an interior, the system comprising: a pump
provided in a center of the wheel for discharging compressed air in
synchronization with rotation of the wheel, the pump including a
discharge section from which the compressed air is discharged; a
conduit connecting between the interior of the tire and the
discharge section of the pump; a check valve provided in the
conduit for preventing the air in the interior of the tire from
flowing to the pump side; and a release valve provided in the
conduit for releasing the compressed air from the pump into an
outside when an internal pressure is at or above a predetermined
value in a section of the interior of the conduit between the check
valve and the pump.
24. A vehicle comprising a tire pressure holding system for a
vehicle having at least a wheel and a tire mounted around the
wheel, the tire having an interior, the system comprising: a pump
provided in a center of the wheel for discharging compressed air in
synchronization with revolution of the wheel, the pump including a
discharge section from which the compressed air is discharged; a
conduit connecting between the interior of the tire and the
discharge section of the pump; a check valve provided in the
conduit for preventing the air in the interior of the tire from
flowing to the pump side; and a release valve provided in the
conduit for releasing the compressed air from the pump into an
outside when an internal pressure is at or above a predetermined
value in a section of the interior of the conduit between the check
valve and the pump.
25. A tire valve unit fixed to an outer edge of a wheel having a
tire fitted around the wheel, the unit comprising; a stem having a
space capable of communicating with the interior of the tire; a
check valve fixed in the stem and being capable of supplying air
into the tire, the check valve further preventing the air in the
tire from leaking outside; a pump connector provided in a central
portion of the wheel and connected via a pipe to the pump
discharging compressed air in synchronization with revolution of
the wheel, so that the compressed air is introduced into the stem;
and a release valve releasing the compressed air from the pump into
an outside when an internal pressure is at or above a predetermined
value in a section of the interior of the stem nearer to the pump
than the check valve.
26. A tire valve unit according to claim 25, wherein the check
valve and the release valve are linked with each other so that when
either one of the check valve and the release valve is opened, the
other is closed.
27. A tire valve unit according to claim 26, wherein the check
valve includes a valve core further including a cylindrical member
having an open end, a shaft extending through the cylindrical
member and having an end, a check valve lid fixed to the end of the
shaft and a check valve urger which urges the lid so that the end
of the cylindrical member is closed, the valve core being
accommodated in the stem with the check valve lid being disposed at
the tire side, and the release valve includes a communicating
passage providing communication between the interior of the conduit
and the outside, a release valve lid direct moved between a first
position where the communicating passage is closed by the lid and a
second position where the communicating passage is opened by the
lid, and a release valve urger which urges the release valve lid
toward the first position, and the check valve and the release
valve are associated with each other so that when either one of the
check valve and the release valve is opened, the other is
closed.
28. A tire valve unit according to claim 25, further comprising an
intermediate valve provided between the release valve and the check
valve in the conduit, wherein the intermediate valve includes a
shaft direct moved in the conduit, a generally disc-shaped sealing
member fitted with an outer circumferential face of the shaft and
having an outer edge curved so as to be pushed out toward the check
valve, the sealing member being adhered closely to a
circumferential face of the conduit, and a limiting plate placed on
the sealing member and limiting elastic deformation of the sealing
member in the direction opposite to the check valve and allowing
the sealing member to elastically deform toward the check
valve.
29. A tire valve unit according to claim 28, wherein the
intermediate valve is moved toward the check valve when the sealing
member is subjected to the compressed air from the pump, thereby
pressing the check valve so as to open the check valve.
30. A tire valve unit according to claim 25, wherein the conduit
includes an external pump mount communicating with a space between
the release valve and the check valve, the system further
comprising an external pump discrete from the vehicle and
detachably attached to the external pump mount.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] This invention relates to a vehicle provided with pneumatic
tires, such as bicycles, motorbikes, motorcycles, automobiles and
air-planes, a tire pressure holding system which can be provided in
the vehicle, a tired wheel and a valve unit suitable for use with a
tire.
[0003] 2. Description of the Related Art
[0004] There has conventionally been provided a bicycle with an
integral bicycle pump. For example, JP-A-2000-335471 discloses such
a bicycle. The disclosed bicycle is illustrated in FIG. 16 of the
present application. As shown in FIG. 16, a packing 3 is attached
to a lower end of a support 2 of a saddle 1. The support 2 is
inserted in a pipe 4 of a bicycle frame so that the packing 3 is
slidable in the pipe. A hose 5 connected to a lower end of the pipe
4 is further connected to a tire valve (not shown). Compressed air
is supplied into a tire when the support 2 is moved up and down
with the saddle 1.
[0005] However, the above-described construction cannot eliminate a
work of supplying air into the tire. Accordingly, a frequent work
of supplying air into the tire is required so that an internal
pressure of the tire is maintained at a suitable value.
Furthermore, the tire can be excessively deformed when a user or
rider is unaware of a reduction in the internal pressure of the
tire.
SUMMARY OF THE INVENTION
[0006] Therefore, an object of the present invention is to provide
a tire pressure holding system which can automatically supply
compressed air into the tire, a tired wheel provided with such a
system and a valve unit suitable for use in such a system.
[0007] The present invention provides a tire pressure holding
system for a vehicle having at least a wheel and a tire mounted
around the wheel, the tire having an interior. The system comprises
a pump provided in a center of the wheel for discharging compressed
air in synchronization with revolution of the wheel, the pump
including a discharge section from which the compressed air is
discharged, a conduit connected to the tire and the discharge
section of the pump, a check valve provided in the conduit for
preventing the air in the interior of the tire from flowing to the
pump side, and a release valve provided in the conduit for
releasing the compressed air from the pump outside when an internal
pressure is at or above a predetermined value in a section of the
interior of the conduit between the check valve and the pump.
[0008] When the vehicle is run, the pump is driven in
synchronization with revolution of the wheel to supply the
compressed air into the conduit. In this case, when an internal
pressure of the tire is lower than a normal pressure, the check
valve is opened due to the difference between an internal pressure
of the conduit and the internal pressure of the tire, whereby the
compressed air is supplied into the tire. The check valve is closed
when the difference between the internal pressures of the conduit
and the tire is rendered smaller upon completion of compressed air
supply into the tire. Furthermore, when the internal pressure of
the conduit is increased to a value equal to or larger than a
predetermined value, the release valve is opened to release the
compressed air from the pump to the outside. Thus, the compressed
air can automatically be supplied into the tire. Moreover,
compressed air, when excessively supplied, is released outside,
whereupon the internal pressure of the tire can be stabilized.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] Other objects, features and advantages of the invention will
become clear upon reviewing the following description of
embodiments, made with reference to the accompanying drawings, in
which:
[0010] FIG. 1 is a side view of a bicycle in accordance with one
embodiment of the present invention;
[0011] FIG. 2 is a sectional side view of a tire pressure holding
system provided on the bicycle;
[0012] FIG. 3 is a sectional side view of a valve unit with a
release valve thereof being closed;
[0013] FIG. 4 is a sectional side view of the valve unit with the
release valve being opened;
[0014] FIG. 5 is a sectional side view of a valve core in the open
state;
[0015] FIG. 6 is a sectional side view of the valve core in the
closed state;
[0016] FIG. 7 is a sectional side view of the valve unit in
accordance with a second embodiment of the invention with the
release valve being closed;
[0017] FIG. 8 is a sectional side view of the valve unit with the
release valve being opened;
[0018] FIG. 9 is a sectional side view of the valve unit in
accordance with a third embodiment of the invention;
[0019] FIG. 10 is a sectional sideview of the valve unit in
accordance with a fourth embodiment of the invention;
[0020] FIG. 11 is a sectional side view of the valve unit in
accordance with a fifth embodiment of the invention;
[0021] FIG. 12 is a sectional side view of the tire pressure
holding system in accordance with a sixth embodiment of the
invention;
[0022] FIG. 13 is a sectional side view of a pump in accordance
with a seventh embodiment of the invention;
[0023] FIG. 14 is a sectional side view of the pump in another
operating state;
[0024] FIG. 15 is a sectional front view of the pump; and
[0025] FIG. 16 is a sectional view of a pump provided on a
conventional bicycle.
DETAILED DESCRIPTION OF THE INVENTION
[0026] A first embodiment of the present invention will be
described with reference to FIGS. 1 to 6. Referring to FIG. 1, a
bicycle 10 is shown as a vehicle in accordance with the present
invention. The bicycle 10 includes front and rear wheels 11 each of
which includes a centrally disposed pump 12 in accordance with the
invention. Each wheel 11 further includes a plurality of hub spokes
15 secured to an outer periphery of the pump 12 and a reel 14 with
which a tire 13 is fitted.
[0027] Referring to FIG. 2, an inner structure of the pump 12 is
shown. The pump 12 produces compressed air by a coherent mechanism
20. More specifically, the pump 12 includes a rotary block 21
formed into a generally cylindrical shape and having opposite ends
including a bottom. A cylindrical inner housing 24 is enclosed in
the rotary block 2l. The inner housing 24 is rotatably mounted on a
shaft further mounted on both end walls 21T of the rotary block 21
so as to be in contact with a part of the inner circumferential
face of the rotary block 21. The rotary block 21 has an axial
center located inside the inner housing 24. An axle 22 of the
bicycle 10 extends along the axial center of the rotary block 21
through the latter. The axle 22 has both ends secured to a body of
the bicycle 10 so as to be unrotatable. When the bicycle 10 is run,
the rotary block 21 is rotated about the axle 22.
[0028] A partition projection 23 is fixed to the axle 22. The
projection 23 extends through a slit 24S formed in the
circumferential face of the inner housing 24, abutting the inner
circumferential face of the rotary block 21. Upon revolution of the
wheel 11, the projection 23 is turned in the rotary block 21. The
inner housing 24 is rotated in the rotary block 21 with turn of the
projection 23. As a result, a space defined between the rotary
block 21 and the inner housing 24 is divided by the projection 23
into two chambers 12K. The capacity of each chamber 12K is
increased or decreased in synchronization with revolution of the
wheel 11.
[0029] The rotary block 21 has a circumferential wall 21E formed
with an inlet 25 and an outlet section 26 between which the contact
portion of the rotary block 21 with the inner housing 24 is
disposed. When the wheel 11 is revolved counterclockwise as viewed
in FIG. 2, air introduced through the inlet 25 into the chamber 12K
is converted into compressed air, which is discharged through the
outlet section 26. The outlet section 26 is provided with a
cylindrical wall 27 projecting from the circumferential wall 21E. A
pipe joint 28 is screwed into a distal end of the cylindrical wall
27. A pipe 29 has one of two ends which is fixed to the pipe joint
28 as shown in FIG. 2. The other end of the pipe 29 extends to the
reel 14 side of the wheel 11 to be fixed to a tire valve unit 30.
The outlet section 26 of the pump 12, the valve unit 30 and the
pipe 29 constitute a tire pressure holding system in accordance
with the present invention.
[0030] Referring to FIG. 3, the valve unit 30 is shown in more
detail. The valve unit 30 includes a shaft-like stem 32 extending
through a through hole 14A formed in the reel 14. A tire tube 13C
provided inside the tire 13 is fixed to a proximal end of the stem
32, whereupon a space 32A axially defined inside the stem 32
communicates with an inner space 13A of the tire 13 or more
specifically, with an inner space of the tire tube 13C. More
specifically, the stem 32 includes a base stem 33 fixed to the tire
tube 13C and an extended stem 34 engaged with an outer face of the
base stem 33. An annular disc 35 is also engaged with the outer
face of the base stem 33. An edge of the through hole 14A is held
between the extended stem 34 and the disc 35, whereupon the stem 32
is fixed so as to stand from the reel 14 toward the pump 12.
[0031] The stem 32 further includes a valve core 40 and a release
valve 65 disposed in turn in this order from the tire 13 side. The
valve core 40 includes a flange-like rubber plug 62 fixed to one
end of a shaft 61 extending through a cylindrical member 60 as
shown in FIG. 5. The rubber plug 62 serves as a check valve lid in
the present invention. When the shaft 61 is urged to one side by a
coil spring 63 provided in the cylindrical member 60 so that the
rubber plug 62 is normally pressed against one open end of the
cylindrical member to close the valve core 40, as shown in FIG. 5.
The coil spring 63 thus serves as check valve urging means in the
invention. When the shaft 61 is moved against the coil spring 63,
the rubber plug 62 is separated from the cylindrical member 60,
whereby the valve core 40 is opened so that air is allowed to flow
therethrough, as shown in FIG. 6.
[0032] The release valve 66 has such an elongated shape as to be
direct moved in the extended stem 34 and includes a flange 67 on an
end at the side thereof spaced away from the valve core 40, as
shown in FIG. 3. A surrounding wall 68 projects from an outer edge
of the flange 67 toward the valve core 40. A disc-shaped sealing
member 69 is provided inside the surrounding wall 68. On the other
hand, the extended stem 34 has a stepped portion 34D formed on an
inner face thereof. A circular projecting member 70 projects from
an inner edge of the stepped portion 34D toward a direction in
which the projecting member is departed from the valve core 40.
Furthermore, a coil spring 71 is disposed, in a
compression-deformed state, between the flange 67 of the release
valve 66 and a distal end wall 34S of the extended stem 34. The
sealing member 69 of the release valve 66 is pressed against the
circular projecting member 70 by the spring force of the coil
spring 71.
[0033] The space 32A in the stem 32 includes a release chamber 32C
separated from the valve core 40 as the result of close adherence
of the sealing member 69 of the release valve 65 and the circular
projecting member 70. The release chamber 32C includes a release
hole 73 formed through a side wall of the extended stem 34 near the
projecting member 70. The space 32A further includes a charge
chamber 32B defined by the valve core 40 and a closely adhered
portion between the sealing member 69 of the release valve 65 and
the circular projecting member 70. The charge chamber 32B includes
an air supply hole 72 formed through a side wall of the extended
stem 34. A pipe 29 extending from the pump 12 has an end connected
to the air supply hole 72. The outlet section 26 of the pump 12,
the stem 32 and the pipe 29 constitute a conduit 74 in the
invention, as shown in FIG. 2.
[0034] The release valve 65 has an end against which the shaft 61
of the valve core 60 is pressed. The release valve 65 and the shaft
61 are urged by the aforesaid coil springs 63 and 71 so that the
valve and the shaft are pressed in opposite directions
respectively. Accordingly, the release valve 65 and the shaft 61
are substantially connected to each other, whereupon the valve core
40 is operated in synchronization with release valve 65.
[0035] The operation of the bicycle 10 will now be described. The
pump 12 is inoperative when the bicycle 10 is stopped. In this
case, the valve core 40 is closed and the release valve 65 is open
in the valve unit 30. When the bicycle 10 is run, the pump 12 is
driven in synchronization with revolution of the wheel 11.
Consequently, compressed air is supplied into the charge chamber
32B of the valve unit 30. Part of the compressed air flows through
the release valve 65, leaking from the release hole 73. However,
when the bicycle 10 is run at or above a predetermined speed, an
amount of compressed air supplied from the pump 12 becomes larger
than an amount of compressed air leaking from the release hole 73,
whereupon the internal pressure of the charge chamber 32B is
increased. In this case, when the internal pressure of the tire 13
or the tire tube 13C is lower than that in the normal state of the
tire, the valve core 40 is opened on the basis of a difference
between the internal pressures of the charge chamber 32B and the
tire 13. The release valve 65 is then closed in synchronization
with the opening of the valve core 40, whereby the compressed air
from the pump 12 is supplied into the tire 13. When the internal
pressure of the tire 13 is increased as the result of supply of the
compressed air, the valve core 40 is closed and the release valve
65 is opened in synchronization with the closure of the valve core,
whereupon the compressed air from the pump 12 is released outside
the valve unit 30.
[0036] According to the bicycle 10 of the embodiment, compressed
air can automatically be supplied into the tire 13 and accordingly,
the internal pressure of the tire can be stabilized. Furthermore,
the valve core 40 and the release valve 65 are linked with each
other so that the release valve is held open while the valve core
is closed. Accordingly, since an excessive amount of compressed air
from the pump 12 is smoothly released outside, a revolution
resistance of the wheel 11 can be reduced. Additionally, the tire
pressure holding system 31 of the embodiment is divided into the
pump 12, the valve unit 30 and the pipe 29 connecting the pump and
the valve unit. Consequently, the length of the pipe 29 can be
changed so as to correspond to various sizes of wheels 11, and the
pump 12 and the valve unit 30 can be used as common components for
the various sizes of wheels 11.
[0037] Other embodiments of the invention will be described
hereinafter. In the following description, only the difference from
one or more previous embodiments will be described. Identical or
similar parts in each of the following embodiments are labeled by
the same reference symbols, as those in the previous embodiments,
and accordingly, the description of these parts will be
eliminated.
[0038] FIGS. 7 and 8 illustrate a second embodiment of the
invention. The valve unit 30V of the second embodiment differs from
the valve unit of the first embodiment in the construction of the
release valve 65V. The release valve 65 provided in the valve unit
30V of the second embodiment has a smaller axial length than the
release valve 65 in the first embodiment, so as not to be brought
into contact with the shaft 61 of the valve core 40. Furthermore,
the sealing member 69V is made of a rubber tube with a circular
section into such an annular shape that the sealing member is
fitted in the inside of the surrounding wall 68. The other
construction of the valve unit 30V is the same as that of the valve
unit 30 in the first embodiment.
[0039] In operation of the valve unit 30, both of the valve core 40
and the release valve 65 are closed when the pump 12 is inoperative
due to stop of the bicycle 10, as shown in FIG. 7. Upon run of the
bicycle 10, the pump 12 is driven so that the charge chamber 32B is
charged with compressed air. In this case, when the internal
pressure of the tire 13 is lower than the normal internal pressure,
the valve core 40 is opened due to the difference between the
internal pressures of the charge chamber 32B and the tire 13 to
supply compressed air into the tire 13. The valve core 40 is closed
when the internal pressure of the tire 13 is increased to the
normal internal pressure. In this state, when the compressed air
from the pump 12 increases the internal pressure of the charge
chamber 32B, the release valve 65 is opened to release an excessive
amount of compressed air outside the valve unit 30V. See FIG.
8.
[0040] FIG. 9 illustrates a valve unit 30W in a third embodiment of
the invention. The third embodiment is a modified form of the
second embodiment. An intermediate valve 80 is provided between the
release valve 65 of the stem 32 and the valve core 40. The
intermediate valve 80 includes a shaft 81 direct moved in the
passage 74, a disc-like sealing member 82 and a limiting plate 83.
The sealing member 82 and the limiting plate 83 are fitted onto the
shaft 81 so as to be placed one upon the other.
[0041] The sealing member 82 is made of, for example, a rubber
plate and curved so as to be upwardly convex as viewed in FIG. 9.
The sealing member 82 has an outer circumferential edge closely
adhered to the inner circumferential face of the conduit 74. The
limiting plate 83 is made of, for example, a metal plate and curved
according to the sealing member 82. The limiting plate 83 limits an
elastic deformation of the sealing member 82 in the direction
opposed to the valve core 40, while allowing an elastic deformation
of the sealing member 82 toward the valve core 40 side.
Furthermore, the intermediate valve 80 is adapted to be direct
moved in the passage 74 as described above and urged by a coil
spring 84 toward the valve core 40 side.
[0042] The extended stem 34 has a release hole 73 formed in a
distal end wall 34S thereof. When the release valve 65V is departed
from the circular projection 70, compressed air passes through a
gap defined between the release valve 65V and the inner
circumferential face of the extended stem 34, released outside from
the release hole 73.
[0043] In the valve unit 30W of the third embodiment, when air
leaks at the valve core 40 side, pressure is increased at the valve
core 40 side of the sealing member 82 of the intermediate valve 80.
As a result, the intermediate valve 80 is moved to the side away
from the valve core 40 against a spring force of the coil spring
84, and the sealing member 82 is deformed in the direction opposite
the direction of its curvature thereby to be spread outward.
Consequently, the outer edge of the sealing member 82 is closely
adhered to the inner circumferential face of the stem 32, thereby
preventing air in the tire 13 from leaking outside through the
intermediate valve 80.
[0044] Furthermore, pressure is increased at the side opposite the
valve core 40 in the sealing member 82 when the charge chamber 32B
is charged with compressed air from the pump 12. In this case, the
sealing member 82 is deformed such that the curvature thereof is
increased, whereupon a gap is defined between the inner
circumferential face of the stem 32 and the sealing member 82.
Consequently, air can be supplied through the gap into the tire 13.
Furthermore, the intermediate valve 80 is moved to the valve core
40 side, so that the valve core 40 is pressed by the valve 80 to be
opened. In other words, the intermediate valve 80 and the valve
core 40 are linked with each other so as to be opened together, and
accordingly, compressed air can readily be supplied into the tire
13.
[0045] In the valve unit 30W of the third embodiment, the valve
core 40 and the intermediate valve 80 limit leakage of air from the
tire 13 in association. When the internal pressure of the tire 13
is reduced, air can be supplied through the valve core 40 and the
intermediate valve 80 into the tire 13.
[0046] FIG. 10 illustrates a valve unit 30X in a fourth embodiment
of the invention. The fourth embodiment is a modified form of the
third embodiment. In the stem 32X used in the valve unit 30X, a
first space 86 encloses co-axially aligned valve core 40 and
intermediate valve 80. The first space 86 serves as an air supply
hole 72. The pipe 29 extending from the pump 12 is connected to a
pipe joint 85 communicating with the air supply hole 72. The stem
32 has a second space 87 disposed in parallel with the first space
86. The release valve 65V is provided in the second space 87.
Furthermore, the first space 86 has a chamber located nearer to the
air supply hole 72 than the intermediate valve 80. The chamber
communicates via a cave hole 88 with a chamber of the second space
87 which is located opposite the release hole 73 and defined by the
release valve 65V. The same effect can be achieved from the fourth
embodiment as from the previous embodiments.
[0047] FIG. 11 illustrates a fifth embodiment of the invention. The
fifth embodiment is a modified form of the fourth embodiment. The
stem 32Y of the valve unit 30Y includes a second valve core 89
provided at the distal end side of the first space 86 extending
coaxially with the valve core 40. The distal end of the stem 32Y
serves as an external pump mount 100 in the invention. A cap 102 is
attached to the pump mount 100 by thread engagement. The second
valve core 89 has substantially the same basic construction as the
valve core 40.
[0048] The air supply hole 72 is located between the second valve
core 89 and the intermediate valve 80 and communicates with the
first space 86. A pipe joint 101 is attached to the air supply hole
72 by thread engagement. The pipe 29 extending from the pump 12 is
connected to the pipe joint 101.
[0049] According to the above-described valve unit 30Y, the same
effect can be achieved from the fifth embodiment as from the first
to third embodiments. Furthermore, when an external pump is
connected to the pump mount 100, air can be supplied into the tire
13 by the external pump as occasion demands.
[0050] FIG. 12 illustrates a sixth embodiment of the invention. The
sixth embodiment is also a modified form of the fourth embodiment.
In the valve unit 30Z of the sixth embodiment, the release valve
65V of the valve unit 30X of the fourth embodiment is provided
integrally with the outlet section 26 of the pump 12. More
specifically, the cylindrical wall 27 of the outlet section 26 has
an outlet 27A and a cave hole 27B in which the release valve 65V is
disposed.
[0051] When the release valve 65V is fixed to the pump 12 as
described above, the release valve 65V can be disposed at the
revolution center side of the wheel. Consequently, inertia (moment
of inertia) due to the release valve 65V can be reduced as compared
with a case where the release valve is provided on an outer edge of
the wheel.
[0052] FIGS. 13 to 15 illustrate a seventh embodiment of the
invention. The seventh embodiment differs from the first embodiment
in the construction of the pump. The pump 12V used in the seventh
embodiment employs a slider crank mechanism 20V to produce
compressed air. More specifically, the rotary block 21V of the pump
12V includes a cylindrical member 90 and a cylinder 91 extending
from a side wall of the cylindrical member. The cylindrical member
90 is disposed at the center of the wheel (see FIG. 1), and a
plurality of hub spokes (see FIG. 1) fixed to the circumference of
the cylindrical member 90.
[0053] A crank shaft 92 is provided in the cylindrical member 90.
The crank shaft 92 has both ends unrotatably fixed to the bicycle
body. A piston 93 is provided in the cylinder 91 so as to be direct
moved. A link 94 is provided between the cylinder 91 and the crank
shaft 92. The cylinder 91 has a distal end closed by a bottom wall
95. The outlet section 26V is provided in the bottom wall 95. The
inlet section 25V is provided in a proximal end of the cylinder 91.
A check valve 96 is provided on the side of the outlet section 26V
opposed to the piston 93. The check valve 96 is pushed by
compressed air from the cylinder 91 to be opened, whereas the check
valve is closed when the pressure is negative in the cylinder 91.
The same effect can be achieved from the seventh embodiment as from
the first to sixth embodiments.
[0054] The invention is applied to the bicycle 10 serving as the
vehicle in the foregoing embodiments. However, the vehicle should
not be limited to the bicycle. The invention may be applied to
motorbikes, motorcycles, automobiles, air planes, carriages, etc.
all of which are provided with pneumatic tires.
[0055] The valve core 40 is disposed at the outer edge side of the
wheel 11 in the foregoing embodiments. However, the valve core 40
may be provided integrally on the pump 12, instead. Furthermore,
the hub spokes 15 are fixed to the pump 12 in the foregoing
embodiments. However, a fixing member for the hub spokes and the
pump 12 may be adjacent to each other in the axial direction of the
axle 22, instead. Additionally, the hub spokes 15 extend between
the reel 14 and the central portion of the wheel 11 in the
foregoing embodiments. However, a generally flat disc may be
provided between the reel 14 and the central portion of the wheel
11, instead.
[0056] The foregoing description and drawings are merely
illustrative of the principles of the present invention and are not
to be construed in a limiting sense. Various changes and
modifications will become apparent to those of ordinary skill in
the art. All such changes and modifications are seen to fall within
the scope of the invention as defined by the appended claims.
* * * * *