U.S. patent application number 10/205547 was filed with the patent office on 2004-01-29 for electromagnetically activated on-wheel air pump.
Invention is credited to Moore, Thomas S..
Application Number | 20040016492 10/205547 |
Document ID | / |
Family ID | 30770093 |
Filed Date | 2004-01-29 |
United States Patent
Application |
20040016492 |
Kind Code |
A1 |
Moore, Thomas S. |
January 29, 2004 |
ELECTROMAGNETICALLY ACTIVATED ON-WHEEL AIR PUMP
Abstract
The present invention couples a tire pump with the wheel rim of
a vehicle. The pump is activated electromagnetically to inflate the
tire as desired, e.g. when tire pressure is below a required value.
The pump is arranged to draw air from the atmosphere and pump into
an interior portion of the tire. A magnetized plunger within the
pump is biased to an initial position by a biasing element.
Energizing an electromagnet generates a magnetic field. The pump is
arranged to rotate in and out of the magnetic field to cause the
plunger to reciprocate and inflate the tire.
Inventors: |
Moore, Thomas S.; (Oxford,
MI) |
Correspondence
Address: |
DAIMLERCHRYSLER INTELLECTUAL CAPITAL CORPORATION
CIMS 483-02-19
800 CHRYSLER DR EAST
AUBURN HILLS
MI
48326-2757
US
|
Family ID: |
30770093 |
Appl. No.: |
10/205547 |
Filed: |
July 24, 2002 |
Current U.S.
Class: |
152/418 |
Current CPC
Class: |
B60C 23/126
20200501 |
Class at
Publication: |
152/418 |
International
Class: |
B60C 023/10 |
Claims
What is claimed is:
1. An arrangement for filling a tire mounted on a wheel rim with
air comprising: an electromagnetically activated pump having a pump
body adapted to extend from an inner annular surface of a wheel rim
to an outer annular surface of a wheel rim and having an outlet
port adapted to be in fluid communication with an interior of the
tire; an air inlet disposed on the pump body and in communication
with atmosphere; a plunger comprising a magnetic element, the
plunger disposed within said pump body and having an open position
in which said plunger draws air from said atmosphere into said pump
body through said air inlet, and a closed position in which said
plunger forces air within said pump body through the outlet port; a
biasing element for biasing said plunger toward one of said open or
closed positions; and an electromagnet adapted to be fixedly
located on the vehicle within a defined perimeter proximate the
pump, the electromagnet being selectively energized to be in
magnetic communication with said plunger, said magnetic
communication overcoming the biasing of said plunger.
2. The arrangement of claim 1 wherein the outlet port comprises a
valve arranged to prevent airflow into said pump body and allow
airflow into said inflatable tire.
3. The arrangement of claim 1 wherein said air inlet is arranged to
prevent flow of air from the pump into the atmosphere and allow
flow of air into said pump body.
4. The arrangement of claim 1 wherein said biasing element is a
spring.
5. The arrangement of claim 1 wherein said biasing element is a
permanent magnet in magnetic communication with said plunger.
6. The arrangement of claim 1 wherein said biasing element is
disposed on said pump body.
7. The arrangement of claim 1 wherein said biasing element is
disposed on said wheel rim.
8. The arrangement of claim 1 wherein said electromagnet comprises
an electrically energized coil.
9. The arrangement of claim 8 wherein said coil can be
de-energized.
10. The arrangement of claim 1 wherein said electromagnet comprises
a permanent magnet and an electrically energized coil.
11. The arrangement of claim 1 wherein the electromagnet is mounted
to a brake caliper support.
12. The arrangement of claim 1 wherein said plunger is moved into
magnetic communication with said electromagnet by rotation of said
wheel rim, said magnetic communication forcing said plunger into
said closed position.
13. The arrangement of claim 12 wherein said plunger is moved out
of magnetic communication with said electromagnet by rotation of
said wheel rim, said biasing element forcing said plunger into said
open position.
14. A method for selectively activating a pump to inflate a tire
mounted on a wheel rim, wherein the pump is connected to the wheel
rim, the method comprising the steps of: providing a pump body
extending from an inner annular surface to an annular surface on
the rim and having an inlet communicating with atmosphere and an
outlet port in fluid communication with an interior of the tire;
providing a magnetized plunger within said pump body, the plunger
arranged to reciprocate between an open position in which said
plunger allows air from said atmosphere to enter said pump body
through said inlet, and a closed position in which said plunger
forces air within said pump body through said outlet port; biasing
said plunger toward an initial position selected from one of said
open and closed positions; locating an electromagnet on a fixed
structure within a defined perimeter proximate the pump;
selectively energizing said electromagnet; moving the pump to
position said plunger within a magnetic field generated by the
energized electromagnet to produce a force on the magnetized
plunger sufficient to overcome the bias; moving the pump to
position said plunger out of the magnetic field; and biasing said
plunger toward said initial position.
15. The method of claim 14 wherein said air inlet is arranged to
only allow airflow into said pump body.
16. The method of claim 14 wherein said biasing element is a
spring.
17. The method of claim 14 wherein said biasing element is disposed
on said pump body.
18. The method of claim 14 wherein said biasing element is disposed
on said wheel rim.
19. The method of claim 14 further comprising the step of
selectively energizing said electromagnet in response to a control
signal.
20. The method of claim 14 further comprising the step of
de-energizing said electromagnet in response to a control
signal.
21. The method of claim 17 wherein said electromagnet is disposed
on a vehicular component within close proximity to said wheel
rim.
22. A method for inflating a tire on a vehicle comprising:
positioning a pump to be in fluid communication with the tire and
rotatable therewith relative to the vehicle, said pump including a
magnetized plunger arranged to reciprocate therein to draw air from
the atmosphere and force into the tire; positioning an
electromagnet on a fixed structure of the vehicle and within a
defined range proximate the pump; and selectively energizing the
electromagnet to generate a magnetic field and cause the magnetized
plunger to reciprocate as the pump rotates in and out of the
magnetic field.
23. The method of claim 22 further comprising the step of
selectively energizing said electromagnet in response to a control
signal.
24. The method of claim 23 further comprising the step of
de-energizing said electromagnet in response to a control signal.
Description
FIELD OF THE INVENTION
[0001] The present invention relates to air-inflated tires of
automotive vehicles. More specifically, the invention relates to an
electromagnetically activated pump for inflating the tires on such
vehicles.
BACKGROUND OF THE INVENTION
[0002] Tire pressure is one of the most important elements of
drivability and safety on automotive vehicles. Insufficient tire
pressure may cause excessive or uneven tread wear, decreased fuel
efficiency, and poor traction. Although there are several common
causes of improper tire pressure, most tires will lose air pressure
on a day-to-day basis with normal use. Tires may lose up to and
beyond one pound per square inch (psi) of air pressure per
month.
[0003] It is proper practice, therefore, for an automotive vehicle
operator to check and maintain tire pressure periodically to ensure
adequate performance. Although it is recommended that a vehicle
operator check tire pressure on a regular basis, adequate
maintenance does not always occur. Furthermore, even when tire
pressure is properly monitored, problems may surface. It is
possible for a tire to acquire a slow leak, which an inexperienced
or inattentive operator may not notice. Additionally, changes in
ambient air temperature throughout the day can result in a
significant change in tire pressure.
[0004] It is therefore desirable to provide a means for
self-inflating a tire to counteract normal tire pressure loss. Some
current self-inflating tire pumps rely on the centrifugal force
created by tire rotation to initiate the action of the pump.
However, such an approach to self-inflation is not available at all
vehicle speeds, as such pumps are designed to be activated only
when the centrifugal force exceeds a specific value. Furthermore,
current self-inflation systems do not actually pump the needed air
into the tire until the vehicle speed is reduced. The centrifugal
force must return below the value needed for pump activation in
order to initiate inflation.
[0005] Additionally, some pumps utilize tire pressure monitoring
(TPM) systems. TPM systems communicate tire pressure status to the
vehicle operator through intra-vehicular means such as a dashboard
light or indicator. Vehicles equipped with a TPM system are often
further equipped with a device such as an on-board compressor to
correct air pressure deficiencies. When the TPM system detects a
low tire pressure signal, it relays the information to the on-board
compressor system, which then operates to inflate the corresponding
tire. Such compressor systems are large and bulky and can be
expensive to implement.
SUMMARY OF THE INVENTION
[0006] The present invention integrates a tire pump with the wheel
rim of a vehicle. The pump is activated electromagnetically to
automatically inflate the tire when tire pressure is below a
required value.
[0007] The pump extends from the atmosphere through the wheel rim
and into the interior portion of the tire. The portion of the pump
which is exposed to the atmosphere contains an air inlet for
allowing air into the pump. A plunger within the pump operates to
provide both opened and closed positions. In the open position, air
from the atmosphere is allowed into the pump through the air inlet.
When the plunger moves to the closed position, air is pushed
through a valve into the inflatable portion of the tire.
[0008] The plunger is forced into the open position by a biasing
element. The biasing element retains the plunger in the open
position until an electromagnet is activated. The electromagnet,
which is located on a vehicular component in close proximity with
the wheel rim, reacts against the plunger, which is a permanent
magnet, forcing the plunger into the closed position. The
electromagnet, which is activated upon receiving a low tire signal
from the vehicle's body controller, reacts with the plunger when
normal wheel rotation moves the pump within close proximity to the
electromagnet. The biasing element returns the plunger to the open
position when wheel rotation moves the pump out of the range of the
electromagnet.
[0009] Further areas of applicability of the present invention will
become apparent from the detailed description provided hereinafter.
It should be understood that the detailed description and specific
examples, while indicating the preferred embodiment of the
invention, are intended for purposes of illustration only and are
not intended to limit the scope of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] The present invention will become more fully understood from
the detailed description and the accompanying drawings,
wherein:
[0011] FIG. 1 is a side view of a vehicle wheel employing the
integrated air pump and mounted electromagnet of the present
invention.
[0012] FIG. 2 is a cross-section of the vehicle wheel of FIG. 1
employing the air pump and electromagnet of the present
invention.
[0013] FIG. 3 is a diagram showing the pump of the present
invention with the piston in the open position.
[0014] FIG. 4 is a diagram showing the pump in close proximity with
the electromagnet, causing the piston to be in the closed
position.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0015] Referring to FIG. 1 and FIG. 2, a vehicle wheel 10 as is
used for automotive vehicles includes an inflatable tire 12 which
is mounted on a wheel rim 14 having an inner annular surface 16 and
an outer annular surface 18. An inflatable region 20 is disposed
between the outer annular surface 18 of the wheel rim 14 and the
inner surface of the inflatable tire 12. The wheel 10 is mounted on
an automotive vehicle, bringing the wheel rim 14 in proximity with
vehicle components such as the brake rotor 22 and brake caliper
support 24.
[0016] An electromagnetically activated air pump 30 embodying the
present invention is integrated with the wheel rim 14. The pump 30
extends from the inner annular surface 16 to the outer annular
surface 18. As described more fully below, the pump 30 interacts
with an electromagnet 32 mounted on the brake caliper support 24 to
force air from the atmosphere through the wheel rim 14 and into the
inflatable tire 12.
[0017] Referring to FIG. 2, a cross-section of the vehicle wheel 10
mounted on a vehicle axle 40 is shown. The radially inner portion
42 of the pump 30 is exposed to atmosphere. The pump 30 passes
through the wheel rim 14 and terminates with the radially outer
portion 44 in fluid communication with the interior of inflatable
tire 12. An electromagnet 32 is mounted on a vehicular component
within the perimeter defined by the inner annular surface 16 of the
wheel rim 14. Although the electromagnet 32 as shown is mounted on
the brake caliper support 24, those skilled in the art will
anticipate that the electromagnet 32 may be mounted on other
proximate vehicular components. Likewise, the pump 30 may be
mounted elsewhere on the annular portion of the wheel rim 14. In
one possible alternative arrangement, the pump 30 is mounted
parallel to the axis of the wheel 10. In this arrangement, the
centrifugal force created by tire rotation has a minimized effect
on the performance of the pump 30.
[0018] As shown in FIG. 3, the pump 30 includes an air inlet 50.
The air inlet 50 is disposed on the radially inner portion 42 of
the pump body 52. A plunger 54 having a magnet integrated therewith
is disposed within the pump body 52. The plunger 54 may be
magnetic, or include a magnetic component fixedly attached thereto.
The plunger 54 is shown in the open position, which allows air from
the atmosphere to enter the pump body 52 through the air inlet 50.
A biasing element 56 retains the plunger 54 in the open position.
As shown, the biasing element 56 is illustrated as a spring. In one
possible alternative embodiment, the biasing element 56 may be a
permanent magnet disposed within the pump body 52 which retains the
magnetic plunger 54 in the open position. The air inlet 50 can be a
one-way valve which allows air from the atmosphere through the air
inlet 50 into the pump body 52, but prevents air from within the
pump body 52 from entering the atmosphere.
[0019] Referring to FIG. 3 and FIG. 4, the radially outer portion
44 communicates with the inflatable tire 12. Air within the pump
body 52 is forced through the radially outer portion 44 as the
magnetic plunger 54 moves into the closed position, as shown in
FIG. 4. In the exemplary embodiment shown, the radially outer
portion 44 includes a one-way valve 58 which allows air to enter
the inflatable tire 12 but prevents air from entering the pump body
52 from the inflatable tire 12. The shape of the plunger 54 is
substantially equivalent to that of the pump body 52 so as to allow
the plunger 54 to reciprocate within the pump body 52. In one
embodiment, the plunger 54 and the pump body 52 are
cylindrical.
[0020] The electromagnet 32 is fixedly located so that normal
rotation of the wheel rim 14 will move the pump 30, and therefore
the magnetic plunger 54, within proximity of the electromagnet 32.
When the magnetic plunger 54 is within a predetermined range of the
electromagnet 32, if the electromagnet 32 is energized a force is
exerted on the plunger 54 of sufficient strength to overcome the
biasing element 56, causing the plunger 54 to move to the closed
position as shown in FIG. 4. When normal rotation of the wheel rim
14 moves the plunger 54 out of proximity with the electromagnet 32,
the resulting absence of magnetic force upon the plunger 54 from
the electromagnet 32 allows the biasing element 56 to return the
plunger 54 to the open position as shown in FIG. 3.
[0021] The electromagnet 32 includes an electric coil 60. When the
electric coil 60 is selectively energized, it provides the magnetic
field of the electromagnet 32. When the electric coil 60 is not
energized, no magnetic field is produced, regardless of whether the
plunger 54 and electromagnet 32 are in proximity. In an alternative
embodiment, the electromagnet 32 is a permanent magnet which is
enhanced by the electric coil 60. When the electric coil 60 is
energized, the strength of the resulting magnetic field is added to
the strength of the permanent magnet. With this arrangement, the
relative size of the electromagnet 32 and the electric coil 60 may
be reduced while maintaining sufficient strength to overcome the
biasing element 56. Correspondingly, the power delivered to the
electric coil 60 may be reduced.
[0022] When pressure in the inflatable tire 12 is low due to
insufficient air such as detected by a tire pressure monitoring
arrangement, the electric coil 60 receives an activation command
from a vehicle controller (not shown). When the coil is activated,
the electromagnet 32 and biasing element 56 exert off-step opposing
forces upon the plunger 54 due to normal rotation of the wheel rim
14. The subsequent reciprocating motion of the plunger 54 causes
air to be drawn into the pump body 52 through the air inlet 50 and
then pumped into the inflatable tire 12. When pressure within the
inflatable tire 12 returns to a sufficient level, the electric coil
60 is deactivated, and the plunger 54 returns to the open
position.
[0023] It is to be understood that the configuration of the pump 30
may be implemented in ways other than those illustrated. In one
embodiment, the electromagnet 32 forces the plunger 54 into the
open position, and the biasing element 56 returns the plunger 54 to
the closed position. Alternatively, the radially outer portion 44
of the pump 30 further comprises a valve which allows air to enter
the pump body 52 from the inflatable tire 12 when pressure within
the inflatable tire 12 is excessive. Such a situation may arise due
to ambient temperature changes.
[0024] It is also to be understood that the activation of the
electric coil 60 may be achieved using different methods. In one
embodiment, the electric coil 60 is activated by a controller.
Alternatively, the electric coil 60 can be selectively activated by
a vehicle operator from within the vehicle. Additionally, the tire
pressure at which the electric coil 60 is activated may be varied
according to operator preference, tire specifications, and
environmental conditions. In the case of a leak in the inflatable
tire 12, the electric coil 60 will experience near-continuous
activation. In this circumstance, a feedback or other suitable
detection arrangement capable of detecting such constant, or near
constant, activation of the pump could be provided to notify the
operator that such a leak is present.
[0025] The description of the invention is merely exemplary in
nature and, thus, variations that do not depart from the gist of
the invention are intended to be within the scope of the invention.
Such variations are not to be regarded as a departure from the
spirit and scope of the invention.
* * * * *