U.S. patent application number 14/486146 was filed with the patent office on 2015-03-19 for electric pump and cleaning device for on-vehicle optical sensor.
This patent application is currently assigned to ASMO CO., LTD.. The applicant listed for this patent is ASMO CO., LTD.. Invention is credited to Keita Kawai, Tomoyuki Kikuta.
Application Number | 20150078940 14/486146 |
Document ID | / |
Family ID | 52623748 |
Filed Date | 2015-03-19 |
United States Patent
Application |
20150078940 |
Kind Code |
A1 |
Kikuta; Tomoyuki ; et
al. |
March 19, 2015 |
ELECTRIC PUMP AND CLEANING DEVICE FOR ON-VEHICLE OPTICAL SENSOR
Abstract
An electric pump includes a cylinder, a piston, a motor, and a
discharge valve. The cylinder includes a valve port and a discharge
port, which is in communication with the valve port. The discharge
valve opens and closes the valve port. When the piston is moved
forth to narrow a void in the cylinder, air is compressed in the
cylinder. The discharge valve opens when operated by the piston
that moves forth. The discharge valve opens and discharges
compressed air from the valve port so that fluid including air is
discharged from the discharge port.
Inventors: |
Kikuta; Tomoyuki;
(Toyohashi-shi, JP) ; Kawai; Keita;
(Toyohashi-shi, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
ASMO CO., LTD. |
Shizuoka-ken |
|
JP |
|
|
Assignee: |
ASMO CO., LTD.
Shizuoka-ken
JP
|
Family ID: |
52623748 |
Appl. No.: |
14/486146 |
Filed: |
September 15, 2014 |
Current U.S.
Class: |
417/432 ;
417/443 |
Current CPC
Class: |
B60S 1/56 20130101; F04B
7/02 20130101; B60S 1/528 20130101; F04B 53/10 20130101; F04B 23/02
20130101; F04B 17/03 20130101; F04B 13/02 20130101; F04B 19/06
20130101 |
Class at
Publication: |
417/432 ;
417/443 |
International
Class: |
F04B 19/06 20060101
F04B019/06; F04B 7/02 20060101 F04B007/02; F04B 23/02 20060101
F04B023/02 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 19, 2013 |
JP |
2013194215 |
Jul 3, 2014 |
JP |
2014137676 |
Claims
1. An electric pump comprising: a tubular cylinder including a
valve port and a discharge port, which is in communication with the
valve port, wherein inner and outer sides of the cylinder are in
communication through the valve port; a piston that is movable back
and forth in the cylinder; a motor that drives and moves the piston
back and forth; and a discharge valve that functions to open and
close the valve port, wherein when the piston is moved forth to
narrow a void in the cylinder, air is compressed in the cylinder,
the discharge valve is configured to open when operated by the
piston that moves forth, and the discharge valve opens and
discharges compressed air from the valve port so that fluid
including air is discharged from the discharge port.
2. The electric pump according to claim 1, wherein the discharge
valve includes an operation projection that projects into the
cylinder, and the discharge valve is operated when the operation
projection is pushed by the piston.
3. The electric pump according to claim 1, wherein the cylinder
includes a liquid inlet, and washer liquid is drawn through the
liquid inlet into a void between the valve port and the discharge
port.
4. The electric pump according to claim 3, wherein a fluid check
valve is arranged in the liquid inlet to permit the washer liquid
to flow into a void between the valve port and the discharge port
and prevent reversed flow of the fluid.
5. The electric pump according to claim 3, wherein a liquid
reservoir that is capable of storing the washer liquid drawn
through the liquid inlet is located between the valve port and the
discharge port.
6. The electric pump according to claim 5, wherein a holding valve
is located in a portion of the liquid reservoir proximate to the
discharge port, and the holding valve prevents outflow of washer
liquid from the discharge port when the discharge valve is closed,
and the holding valve opens when the discharge valve opens.
7. The electric pump according to claim 5, wherein the valve port,
the liquid reservoir, and the discharge port are arranged along a
straight line.
8. The electric pump according to claim 1, further comprising a
biasing member that biases the discharge valve to close, wherein
the biasing member has characteristics set so as not to open the
discharge valve with the compressed air.
9. The electric pump according to claim 1, further comprising a
speed reduction mechanism that reduces the speed of rotation
produced by the motor and transmitted to the piston.
10. An on-board optical sensor cleaning device comprising: an
electric pump including a tubular cylinder including a valve port
and a discharge port, wherein inner and outer sides of the cylinder
are in communication through the valve port, a piston that is
movable back and forth in the cylinder, a motor that drives and
moves the piston back and forth, and a discharge valve that
functions to open and close the valve port, wherein when the piston
is moved forth to narrow a void in the cylinder, air is compressed
in the cylinder, the discharge valve is configured to open when
operated by the piston that moves forth, and the discharge valve
opens and discharges compressed air through the valve port and from
the discharge port; a nozzle connected to the discharge port,
wherein the nozzle includes an ejection port; and a mixing member
that connects the discharge port and the nozzle and includes a
liquid inlet, wherein washer liquid is drawn through the liquid
inlet, wherein the on-board optical sensor cleaning device ejects
fluid including air from the ejection port toward an external image
capturing surface of an on-board optical sensor mounted on a
vehicle to remove foreign material from the external image
capturing surface.
11. The on-board optical sensor cleaning device according to claim
10, wherein a liquid reservoir capable of storing the washer liquid
drawn through the liquid inlet is located between the discharge
port and the nozzle in the mixing member.
12. The on-board optical sensor cleaning device according to claim
11, further comprising a washer pump that delivers washer liquid to
the liquid reservoir through the liquid inlet, wherein the washer
pump is driven at the same time as when the motor is driven and
delivers washer liquid to the liquid reservoir before the discharge
valve opens.
13. The on-board optical sensor cleaning device according to claim
11, further comprising a washer pump that delivers washer liquid to
the liquid reservoir through the liquid inlet, wherein the washer
pump is driven for a preset time before the motor is driven.
14. The on-board optical sensor cleaning device according to claim
11, further comprising a washer pump that delivers washer liquid to
the liquid reservoir through the liquid inlet, wherein the washer
pump is driven for a preset time after the discharge valve
opens.
15. The on-board optical sensor cleaning device according to claim
10, wherein the nozzle is configured to be moved by delivering
pressure of fluid including air discharged from the electric pump,
the ejection port is movable to a cleaning position, where the
ejection port is located proximate to an image capturing range
center of the on-board optical sensor.
Description
RELATED APPLICATION
[0001] This application claims benefit of priority of Japanese
Application No. 2014-137676, filed Jul. 3, 2014, said application
being hereby fully incorporated herein by reference.
BACKGROUND OF THE INVENTION
[0002] The present invention relates to an electric pump and a
cleaning device for an on-board optical sensor.
[0003] On-board optical sensors are now often arranged on the front
or rear of vehicles to use the images captured by the on-board
optical sensors. Foreign material such as mud may collect on an
external image capturing surface (lens or protective glass) of such
an on-board optical sensor. Thus, an on-board optical sensor
cleaning device has been proposed to eject air toward an external
image capturing surface from an ejection port of a nozzle (refer
to, for example, Japanese Laid-Open Patent Publication No.
2012-35654).
[0004] An air pump (electric pump) connected to a nozzle that
ejects air has also been proposed (refer to, for example, Japanese
Laid-Open Patent Publication No. 2001-41159). The air pump includes
a tubular cylinder, a piston that is movable back and forth in the
cylinder, an electric drive device that drives and moves the piston
back and forth, a discharge port through which the inner and outer
sides of the cylinder are in communication, and a discharge valve
that functions to open and close the discharge port. The discharge
valve of the air pump is a ball that is biased to perform a closing
action. When the air in the cylinder is compressed, the pressure of
the compressed air results in the ball performing an opening
action. More specifically, in the air pump, when the driving force
of the electric drive device moves the piston to narrow the void in
the cylinder, the air in the cylinder is compressed. The pressure
of the compressed air opens the discharge valve and discharges
compressed air from the discharge port.
[0005] However, in an air pump such as that described above, the
pressure of the compressed air opens the discharge valve. Thus, air
may leak from the discharge valve when undergoing compression. This
may hinder the momentary discharge (ejection) of high-pressure air
having the set (expected) amount and pressure. Further, the
on-board optical sensor cleaning device may therefore fail to clean
the external image capturing surface.
SUMMARY OF THE INVENTION
[0006] It is an object of the present invention to provide an
electric pump and a cleaning device for an on-board optical sensor
that allows for momentary discharge of high-pressure air of a set
amount and a set pressure.
[0007] To achieve the above object, one aspect of the present
invention is an electric pump including a tubular cylinder, a
piston, a motor, and a discharge valve. The cylinder includes a
valve port and a discharge port, which is in communication with the
valve port. Inner and outer sides of the cylinder are in
communication through the valve port. The piston is movable back
and forth in the cylinder. The motor drives and moves the piston
back and forth. The discharge valve functions to open and close the
valve port. When the piston is moved forth to narrow a void in the
cylinder, air is compressed in the cylinder. The discharge valve is
configured to open when operated by the piston that moves forth.
The discharge valve opens and discharges compressed air from the
valve port so that fluid including air is discharged from the
discharge port.
[0008] A further aspect of the present invention is an on-board
optical sensor cleaning device including an electric pump, a
nozzle, and a mixing member. The electric pump includes a tubular
cylinder, a piston, a motor, and a discharge valve. The cylinder
includes a valve port and a discharge port. Inner and outer sides
of the cylinder are in communication through the valve port. The
piston is movable back and forth in the cylinder. The motor drives
and moves the piston back and forth. The discharge valve functions
to open and close the valve port. When the piston is moved forth to
narrow a void in the cylinder, air is compressed in the cylinder.
The discharge valve is configured to open when operated by the
piston that moves forth. The discharge valve opens and discharges
compressed air through the valve port and from the discharge port.
The nozzle is connected to the discharge port. The nozzle includes
an ejection port. The mixing member connects the discharge port and
the nozzle and includes a liquid inlet. Washer liquid is drawn to
the mixing member through the liquid inlet. The on-board optical
sensor cleaning device ejects fluid including air from the ejection
port toward an external image capturing surface of an on-board
optical sensor mounted on a vehicle to remove foreign material from
the external image capturing surface.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] The invention, together with objects and advantages thereof,
may best be understood by reference to the following description of
the presently preferred embodiments together with the accompanying
drawings in which:
[0010] FIG. 1A is a schematic diagram of a vehicle including an
on-board optical sensor cleaning device according to a first
embodiment of the present invention;
[0011] FIG. 1B is a schematic diagram of a display shown in FIG.
1A;
[0012] FIG. 2 is a partially schematic perspective view of the
vehicle including the on-board optical sensor cleaning device shown
in FIG. 1A;
[0013] FIG. 3A is a perspective view of a cleaning unit and an
on-board camera shown in FIG. 2 at a non-cleaning position;
[0014] FIG. 3B is a perspective view of the cleaning unit and the
on-board camera shown in FIG. 2 at a cleaning position;
[0015] FIG. 4 is an exploded perspective view of the on-board
camera and the cleaning unit shown in FIG. 3A;
[0016] FIG. 5 is a cross-sectional view of a nozzle unit shown in
FIG. 4;
[0017] FIG. 6 is a cross-sectional view of an air pump shown in
FIG. 1A;
[0018] FIGS. 7A to 7D are cross-sectional views each illustrating
the operation of the air pump in FIG. 6;
[0019] FIG. 8 is a time-pressure/velocity characteristic diagram
illustrating the results of an experiment conducted on the air pump
of FIG. 6;
[0020] FIG. 9 is a cross-sectional view of an air pump in a further
example;
[0021] FIGS. 10A to 10C are cross-sectional views each illustrating
the operation of an air pump in a further example;
[0022] FIG. 11 is a cross-sectional view of an electric pump in a
further example;
[0023] FIG. 12 is a partially enlarged cross-sectional view of the
electric pump in the further example;
[0024] FIG. 13 is a partially enlarged cross-sectional view
illustrating the operation of the electric pump in the further
example;
[0025] FIG. 14 is a partially enlarged cross-sectional view
illustrating the operation of the electric pump in the further
example;
[0026] FIG. 15 is a partially enlarged cross-sectional view of an
electric pump in a further example;
[0027] FIG. 16 is a schematic diagram of the on-board optical
sensor cleaning device in the further example;
[0028] FIG. 17 is a time chart showing the operation of a washer
pump and an air pump in the further example;
[0029] FIG. 18 is a time chart showing the operation of the washer
pump and the air pump in the further example;
[0030] FIG. 19 is a time chart showing the operation of the washer
pump and the air pump in the further example; and
[0031] FIG. 20 is a cross-sectional view of an air pump in a
further example.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0032] One embodiment of an on-board optical sensor cleaning device
mounted on a vehicle will now be described with reference to FIGS.
1A to 8.
[0033] As shown in FIG. 1A, the rear of a vehicle 1 includes a back
door 2.
[0034] As shown in FIG. 2, the back door 2 includes a metal vehicle
panel 3 and a plastic garnish 4 partially covering the vehicle
panel 3. The garnish 4 includes an opening 4a that opens toward the
lower side. The back door 2 includes an on-board camera 5, which
serves as an on-board optical sensor, and a cleaning unit 6. A
portion of the on-board camera 5 and a portion of the cleaning unit
6 are exposed from the opening 4a.
[0035] As shown in FIGS. 3A to 4, the on-board camera 5 includes a
generally box-shaped main body 5a, which accommodates an image
capturing element (not shown), a tube 5b, which extends from one
surface of the main body 5a, and a lens 5c, which covers the distal
end of the tube 5b and serves as an external image capturing
surface. The on-board camera 5 is fixed to the vehicle panel 3.
[0036] As shown in FIGS. 1A and 1B, for example, when a shift lever
81 of a transmission is moved to a reverse position, the on-board
camera 5 transmits captured images of the rear of the vehicle 1 to
a display 80, which shows the images.
[0037] As shown in FIGS. 3A to 4, the cleaning unit 6 includes a
fastening member 7, which is fastened to the on-board camera 5, and
a nozzle unit 8, which is fastened to the fastening member 7. The
fastening member 7 includes two holding claws 7a. The fastening
member 7 is fixed to the on-board camera 5 so that the holding
claws 7a hold the main body 5a of the on-board camera 5. The
fastening member 7 includes two fastened pieces 7b. Opposing
surfaces of the fastened pieces 7b each include a groove. The
nozzle unit 8 is fixed to the fastened pieces 7b.
[0038] As shown in FIGS. 3A to 5, the nozzle unit 8 includes a
generally tubular first case 9 and a second case 10 fitted and
fixed to the basal end of the first case 9. The circumference of
the first case 9 includes two fastening projections 9a (only one
shown in FIGS. 3A to 4). The fastening projections 9a are fitted to
the grooves of the fastened pieces 7b to fix the nozzle unit 8 to
the fastened pieces 7b. An inlet tube 10a is formed at the bottom
of the second case 10. The inlet tube 10a projects from the bottom
of the second case 10. An inlet 10b (refer to FIG. 5) is formed in
the inlet tube 10a in communication with the interior of the first
case 9. A seal ring 82 is held between the first case 9 and the
second case 10.
[0039] As shown in FIGS. 4 and 5, the nozzle unit 8 includes a
nozzle 11 and a compression coil spring 12. The nozzle 11 is able
to move forward and rearward relative to the first case 9 in order
to move out of and into the first case 9 through a distal opening.
The compression coil spring 12 biases the nozzle 11 in the rear
direction (direction toward basal end of first case 9).
[0040] In detail, as shown in FIG. 5, the nozzle 11 is tubular and
has a smaller diameter than the first case 9. Further, the distal
portion of the nozzle 11 includes an ejection port 11a that extends
sideward (direction orthogonal to longitudinal direction). A basal
member 13 is fitted and fixed to the basal portion of the nozzle
11. A seal ring 83 is held between the nozzle 11 and the basal
member 13. The basal member 13 includes a flange 13a extending
toward the outer side in the radial direction. One end of the
compression coil spring 12 is supported by the distal portion of
the first case 9. The compression coil spring 12 biases the flange
13a to bias the nozzle 11 in the rearward direction (right
direction as viewed in FIG. 5). An annular seal member 14, which
contacts and slides along the inner circumferential surface of the
first case 9, is fitted to the basal portion of the basal member
13.
[0041] Restriction rods 10c extend from the bottom of the second
case 10 in a direction opposite to the inlet tube 10a. In this
example, three restriction rods 10c (only two shown in FIG. 5) are
formed at equal angular intervals in the circumferential direction.
The restriction rods 10c contact the basal end surface of the basal
member 13, which is biased by the compression coil spring 12, and
restricts rearward movement of the basal member 13 (nozzle 11) from
the position of contact.
[0042] As shown in FIG. 1A, a hose 84 connects an air pump 85 to
the inlet tube 10a (inlet 10b). The air pump 85 is able to
momentarily discharge compressed high-pressure air. Further, the
air pump 85 is driven to supply the nozzle unit 8 with air from the
inlet 10b. The air pump 85 is driven, for example, when a switch
arranged in the passenger compartment is operated or immediately
before the on-board camera 5 starts capturing images.
[0043] When compressed air is supplied from the inlet 10b to the
interior of the nozzle 11, which is arranged as described above,
the delivering pressure of the air biases the basal end surface of
the basal member 13 and moves the nozzle 11 forward against the
biasing force of the compression coil spring 12.
[0044] Forward and rearward movement of the nozzle 11 allows for
movement of the ejection port 11a between a cleaning position,
where the ejection port 11a is located proximate to the image
capturing range center X (refer to FIG. 1B) of the on-board camera
5, and a non-cleaning position, where the ejection port 11a is
located farther from the image capturing range center X than the
cleaning position. The image capturing range of the present
embodiment is the range in which the on-board camera 5 (image
capturing element of on-board camera 5) captures images through the
lens 5c and is the range shown on the display 80.
[0045] Specifically, in the present embodiment, the non-cleaning
position is set where the ejection port 11a is located outside the
image capturing range of the on-board camera 5 (refer to
double-dashed lines in FIG. 1B). Further, the cleaning position is
set where the ejection port 11a is located in the image capturing
range of the on-board camera 5 (refer to solid lines in FIG. 1B).
That is, when the nozzle 11 is moved toward the rear to a rear
position (basal end surface of basal member 13 in contact with the
restriction rods 10c), the ejection port 11a is located at the
non-cleaning position outside the image capturing range of the
on-board camera 5. When the nozzle 11 is moved toward the front to
a front position, the ejection port 11a is located at the cleaning
position inside the image capturing range of the on-board camera 5.
In FIG. 1B, the solid lines indicate the background shown in the
display 80 and the ejection port 11a (distal portion of nozzle 11)
located in the image capturing range. Further, the double-dashed
lines schematically indicate the ejection port 11a (distal portion
of nozzle 11) located outside the image capturing range.
[0046] In the present embodiment, the direction in which the nozzle
11 is able to move forward and rearward is inclined relative to the
direction the lens 5c of the on-board camera 5 faces toward (center
axis of lens 5c). That is, when the nozzle 11 is moved forward to
the front position, the ejection port 11a is located proximate to
the image capturing axis (center axis of the lens 5c) and closer to
the center of the image capturing range of the on-board camera 5.
Further, the nozzle 11 is inclined so that cleaning liquid is
ejected from the ejection port 11a to the center position of the
lens 5c.
[0047] Referring to FIG. 6, the air pump 85 of the present
embodiment includes a cylinder 21, which is tubular and has a
closed end, a piston 22, which is movable back and forth in the
cylinder 21, and a motor 23, which serves as a drive device that
drives and moves the piston 22 back and forth. Further, the air
pump 85 includes a discharge port 24, which communicates the inner
and outer sides of the cylinder 21, a discharge valve 25, which
functions to open and close the discharge port 24, an intake port
26, which communicates the inner and outer sides of the cylinder
21, and an intake valve 27, which functions to open and close the
intake port 26. In detail, the discharge valve 25 functions to open
and close a tapered hole 28c, which serves as a valve port that
communicates the discharge port 24 and the interior of the cylinder
21.
[0048] In detail, the bottom portion (left end as viewed in FIG. 6)
of the cylinder 21 includes a discharge coupling hole 21a and an
intake coupling hole 21b. A discharge member 28, which includes the
discharge port 24, is fixed to the discharge coupling hole 21a, and
an intake member 29, which includes the intake port 26, is fixed to
the intake coupling hole 21b. The discharge member 28 and the
intake member 29 function as portions of the cylinder 21.
[0049] The discharge member 28 includes a basal tube 28a and a
discharge tube 28b. The basal tube 28a extends in the direction the
piston 22 moves back and forth. The discharge tube 28b is in
communication with the basal tube 28a, extends sideward from the
distal portion of the basal tube 28a, and is connected to the hose
84. The basal portion of the basal tube 28a includes the tapered
hole 28c serving as a valve port, the diameter of which decreases
toward the inner side of the cylinder 21.
[0050] The discharge valve 25 includes a main body 25a, which has a
trapezoidal cross-section and is able to be in planar contact with
the wall of the tapered hole 28c, and an operation projection 25b,
which projects from the main body 25a into the cylinder 21. The
discharge valve 25 is movable in the reciprocation direction of the
piston 22. Specifically, the discharge valve 25 is able to perform
a closing action, in the direction in which the main body 25a comes
into planar contact with the wall of the tapered hole 28c, and an
opening action, in the direction in which the main body 25a moves
away from the tapered hole 28c. The basal tube 28a accommodates and
holds a coil spring 30, which serves as a biasing member that
biases the discharge valve 25 to perform a closing action (toward
right side as viewed in FIG. 6). That is, the coil spring 30 biases
the discharge valve 25 in the direction in which the discharge
valve 25 closes the tapered hole 28c. The characteristics of the
coil spring 30 such as the spring constant is set so that
compressed air does not open the discharge valve 25.
[0051] The intake member 29 is tubular and extends in the
reciprocation direction of the piston 22. The basal end of the
intake member 29 includes a communication hole 29a that is in
communication with the interior of the cylinder 21.
[0052] A check valve, which closes the communication hole 29a from
the inner side of the cylinder 21 and opens only when the pressure
in the cylinder 21 becomes lower than that of the exterior, is
employed as the intake valve 27.
[0053] The piston 22 is movable back and forth in the cylinder 21.
The piston 22 slides in contact with the cylinder 21 with a seal
member (not shown) arranged in between. Further, the piston 22
includes a female screw 22a, which extends through the piston 22 in
the reciprocation direction.
[0054] The motor 23 is accommodated and held in a motor case 31.
The motor case 31 is fixed to the open end of the cylinder 21
(right end as viewed in FIG. 6). A rotation shaft 23a of the motor
23 is coupled to a male screw 32, which is rotatable integrally
with the rotation shaft 23a. The male screw 32 is engaged with the
female screw 22a of the piston 22. Thus, when the motor 23 rotates
and drives the rotation shaft 23a forward and backward, the screw
effect of the male screw 32 and the female screw 22a drives and
reciprocates the piston 22. As the piston 22 moves forth to narrow
the void (pump chamber) in the cylinder 21 and the inner end
surface of the piston 22 reaches the operation projection 25b of
the discharge valve 25, the inner end surface further pushes the
operation projection 25b. This opens the discharge valve 25.
[0055] The movement and operation of the on-board optical sensor
cleaning device in the present embodiment will now be
described.
[0056] When the air pump 85 is not driven, the nozzle 11 is moved
to the rear and located at the non-cleaning position due to the
biasing force of the compression coil spring 12 (FIG. 3A). Thus,
the ejection port 11a (distal portion of nozzle 11) is located
outside the image capturing range of the on-board camera 5. As a
result, if an image is captured when cleaning is not performed, the
ejection port 11a (distal portion of nozzle 11) does not obstruct
the image capturing.
[0057] The air pump 85 is driven when, for example, a switch
arranged in the vehicle is operated or immediately before the
on-board camera 5 starts capturing images.
[0058] Specifically, when the motor 23 is driven in a standby state
shown in FIG. 6, the male screw 32 rotates together with the
rotation shaft 23a. The piston 22 moves forth to narrow the void
(pump chamber) in the cylinder 21 shown in FIG. 7A. This compresses
the air in the void (pump chamber).
[0059] As shown in FIG. 7B, when the end surface of the piston 22
reaches the operation projection 25b, the compression of air is
completed. As shown in FIG. 7C, the end surface of the piston 22
further pushes the operation projection 25b. This opens the
discharge valve 25 and momentarily discharges (ejects)
high-pressure air.
[0060] As a result, when the inlet 10b of the nozzle unit 8 is
supplied with high-pressure air, the delivering pressure of the air
moves the nozzle 11 (ejection port 11a) forward to the cleaning
position (refer to FIG. 3B). This arranges the ejection port 11a in
the image capturing range of the on-board camera 5. Further, air is
ejected from the ejection port 11a to the lens 5c. This removes
foreign material or the like from the lens 5c and performs
cleaning.
[0061] Then, as shown in FIG. 7D, when the motor 23 is driven in
the opposite direction, the male screw 32 is rotated together with
the rotation shaft 23a. The piston 22 moves back to enlarge the
void (pump chamber) in the cylinder 21, and the pressure in the
cylinder 21 becomes lower than that of the exterior. When the
intake valve 27 opens and draws air into the cylinder 21, the air
pump 85 returns to the standby state.
[0062] The advantages of the embodiment will now be described.
[0063] (1) The discharge valve 25 opens when operated by the piston
22 that moves forth. Thus, the discharge valve 25 does not open
until operated by the piston 22. Specifically, the air pump 85 of
the present embodiment includes the coil spring 30 that biases the
discharge valve 25 to perform a closing action. The characteristics
of the coil spring 30 are set so that compressed air does not open
the discharge valve 25. Thus, the leakage of air can be prevented
when the air is compressed. Further, high-pressure air of the set
amount and pressure may be momentarily discharged (ejected) when
the piston 22 operates the discharge valve.
[0064] Specifically, the results of an experiment shown in FIG. 8
indicate that the pressure P1 of the void (pump chamber) in the
cylinder 21 of the present embodiment continuously rises until time
T1 when an opening action (valve opening) occurs. Then, the
pressure P1 suddenly decreases. In the present embodiment, the
velocity (speed) V1 of the air ejected from the discharge port 24
is null until time T1 (opening action), and momentarily increases
from time T1. In a comparison subject of the prior art, air leaks
during compression. Thus, the pressure P0 does not rise that much,
and the velocity V0 also does not momentarily increase.
[0065] (2) The discharge valve 25 includes the operation projection
25b, which projects into the cylinder 21. The discharge valve 25 is
operated when the operation projection 25b is pushed by the piston
22. Thus, the operation projection 25b of the discharge valve 25
may easily be operated with the wide surface of the piston 22. If
the discharge valve 25 does not include the operation projection
25b, a projection may be arranged on the piston 22 so that the
projection pushes the discharge valve. Such a structure would need
precision components and precision assembling to accurately
position the projection and the discharge valve. The present
embodiment allows such a situation to be avoided.
[0066] (3) The on-board optical sensor cleaning device includes the
nozzle 11. The nozzle 11 is movable (forward direction) and can be
moved to the cleaning position, where the ejection port 11a is
located proximate to the image capturing range center X of the
on-board optical sensor, by the delivering pressure of the air
discharged from the air pump 85. Since the nozzle 11 can be moved
to the cleaning position only when cleaning is performed, the lens
5c may be cleaned in a favorable manner without obstructing image
capturing. Further, since the nozzle 11 can be moved (forward) by
the delivering pressure of the air discharged from the air pump 85,
there is no need for an electric drive device or the like to enable
movement (forward direction) of the nozzle 11. This allows for the
structure to be simplified. Further, the air pump 85 allows for
momentary discharge (ejection) of high-pressure air of the set
amount and pressure. Thus, the nozzle 11 can be moved to a further
accurately set cleaning position, and the lens 5c may be cleaned in
a further favorable manner.
[0067] (4) The air pump 85 includes the motor 23, which is used to
drive and reciprocate the piston 22. This allows the air pump 85 to
be accurately driven by, for example, a control signal or the
like.
[0068] (5) The screw effect of the male screw 32 and the female
screw 22a, which is produced by driving the rotation shaft 23a to
rotate forward and backward, drives and reciprocates the piston 22.
Thus, the piston 22 and the motor 23 (rotation shaft 23a) may be
arranged in series in the reciprocation direction of the piston 22.
Further, enlargement of the air pump 85 in a direction orthogonal
to the reciprocation direction of the piston 22 may easily be
limited.
[0069] The above embodiment may be modified as described below.
[0070] In the above embodiment, the discharge valve 25 includes the
operation projection 25b, which projects into the cylinder 21. The
discharge valve 25 may be changed to another structure as long as
the structure opens when operated by a piston that moves forth.
[0071] For example, as shown in FIG. 9, the operation projection
25b may be omitted from the discharge valve 25, and a projection
22b may be located on the piston 22. The projection 22b projects
toward the discharge valve 25 to operate the discharge valve 25. In
detail, the projection 22b is sized to enter the tapered hole
28c.
[0072] In the above embodiment, the piston 22 is reciprocated by
the screw effect of the male screw 32 and the female screw 22a. The
piston 22 may be reciprocated by another structure.
[0073] For example, as shown in FIGS. 10A to 10C, a crank plate 42
is fixed to a rotation shaft 41a of a motor 41, which serves as an
electric drive device. A rod 44 connects a radially outer portion
of the crank plate 42 and a piston 43. Rotation of the crank plate
42 reciprocates the piston 43 in the order of FIGS. 10A to 10C.
This would also obtain the same advantages as the above
embodiment.
[0074] In the above embodiment, the nozzle 11 can be moved forward
and rearward. The nozzle 11 may also be movable in directions other
than the forward and rearward directions and be, for example,
pivoted by the delivering pressure of a fluid including air.
[0075] The on-board optical sensor cleaning device of the above
embodiment ejects only air, which is delivered from the air pump
85, to clean the lens 5c. Instead, for example, the air delivered
from the air pump 85 and ejected to the lens 5c may be mixed with a
cleaning liquid delivered from a washer pump. Further, the air pump
85 may be an electric pump including a liquid inlet. Washer liquid
from the washer pump may be drawn through the liquid inlet into a
void between a valve port and a discharge port. The fluid of the
mixture of the washer liquid and air is discharged (emitted) from
the discharge port.
[0076] FIGS. 11 to 14 show an example of such an electric pump. A
discharge member 51 is fixed to the discharge coupling hole 21a of
an electric pump 86 in lieu of the discharge member 28.
[0077] The basal end of the discharge member 51 is fixed to the
discharge coupling hole 21a. The discharge member 51 includes a
liquid reservoir tube 51a, which extends in the reciprocation
direction of the piston 22, and a discharge tube 51b, which further
extends from the distal end of the liquid reservoir tube 51a in the
reciprocation direction of the piston 22. The liquid reservoir tube
51a is in communication with the discharge tube 51b. The hose 84 is
connected to the discharge tube 51b. The discharge tube 51b has a
smaller diameter than that of the liquid reservoir tube 51a. The
interior of the liquid reservoir tube 51a defines a liquid
reservoir 52, and the discharge tube 51b includes an opening that
defines a discharge port 53.
[0078] The basal portion of the liquid reservoir tube 51a includes
a tapered hole 51c serving as a valve port in which the diameter
decreases toward the inner side of the cylinder 21. Further, the
liquid reservoir tube 51a (liquid reservoir 52) accommodates and
holds the discharge valve 25 and the coil spring 30 in the same
manner as the above embodiment.
[0079] A liquid inlet tube 51d is formed beside the liquid
reservoir tube 51a and extends sideward from the liquid reservoir
tube 51a. The liquid inlet tube 51d is in communication with the
liquid reservoir tube 51a and has an open end defining a liquid
inlet 51e leading to the liquid reservoir 52 in the liquid
reservoir tube 51a. The liquid inlet tube 51d (liquid inlet 51e) is
connected to a washer pump 88, which delivers washer liquid from a
washer tank 87 through the liquid inlet 51e into the liquid
reservoir 52. In this example, a washer hose 89 connects the washer
pump 88 to the liquid inlet tube 51d.
[0080] A fluid check valve 54 is arranged on the liquid inlet 51e
to permit the flow of washer liquid into the liquid reservoir 52,
which is the void between the tapered hole 51c and the discharge
port 53, and prevent a reversed flow of fluid from the liquid
reservoir 52. The fluid check valve 54 closes the liquid inlet 51e
from the inner side of the liquid reservoir 52 and opens when the
pressure of the washer liquid delivered from the washer pump 88
becomes higher than the internal pressure of the liquid reservoir
52.
[0081] A holding valve 55 is arranged in a portion of the liquid
reservoir 52 that is proximate to the discharge port 53. The
holding valve 55 prevents the outflow of the washer liquid from the
discharge port 53 when the discharge valve 25 is closed. Further,
the holding valve 55 opens when the discharge valve 25 opens. In
detail, an annular projection 52a projects from a portion of the
liquid reservoir 52 proximate to the discharge port 53 to reduce
the inner diameter. A coil spring 56 biases the holding valve 55
from the portion of the liquid reservoir 52 proximate to the
discharge port 53 toward the annular projection 52a. The holding
valve 55 prevents the outflow of washer liquid when the discharge
valve 25 is closed and opens when the discharge valve 25 opens and
suddenly increases the pressure of the liquid reservoir 52.
[0082] As shown in FIG. 11, the electric pump 86 of the example
does not include the intake coupling hole 21b and the intake member
29. The piston 22 includes an intake passage 22c, which
communicates the inner and outer sides of the cylinder 21 (pump
chamber), and the intake valve 27, which is arranged on the intake
passage 22c and functions in the same manner as the above
embodiment.
[0083] In the electric pump 86 having such a structure, if the
motor 23 (refer to FIG. 11) is driven when washer liquid is stored
beforehand in the liquid reservoir 52, the piston 22 is moved forth
to narrow the void (pump chamber) in the cylinder 21.
[0084] As shown in FIG. 13, the end surface of the piston 22 pushes
the operation projection 25b of the discharge valve 25 and opens
the discharge valve 25 to momentarily discharge (eject)
high-pressure air from the tapered hole 51c. This opens the holding
valve 55 and discharges (ejects) fluid, which is a mixture of the
washer liquid and air in the liquid reservoir 52, from the
discharge port 53. The fluid, which is a mixture of the washer
liquid and air, is ejected to the lens 5c from the ejection port
11a of the nozzle 11 to remove foreign material or the like from
the lens 5c and perform cleaning.
[0085] As shown in FIG. 14, when the motor 23 (refer to FIG. 11) is
driven in the opposite direction, the piston 22 moves back to
enlarge the void (pump chamber) in the cylinder 21. The intake
valve 27 opens when the pressure in the cylinder 21 becomes lower
than that of the exterior. Air is drawn into the cylinder 21
through the intake valve 27. This returns the electric pump 86 to
the standby state. Further, in this state, as shown in FIG. 14, the
washer pump 88 is driven when the piston 22 opens the discharge
valve 25. This delivers washer liquid from the washer tank 87 to
the liquid reservoir 52. The washer liquid is stored in the liquid
reservoir 52.
[0086] In the electric pump 86 (on-board optical sensor cleaning
device) configured in this manner, the liquid inlet 51e, which
allows for washer liquid to be drawn in, is formed between the
tapered hole 51c (valve port) and the discharge port 53. This
allows for the discharge (ejection) of fluid, which is a mixture of
the washer liquid and air, from the discharge port 53.
[0087] Further, the liquid inlet 51e includes the fluid check valve
54, which permits the flow of the washer liquid into between the
tapered hole 51c and the discharge port 53, and prevents a reversed
flow of fluid. Thus, reversed flow of fluid (washer liquid and air)
from the liquid inlet 51e is restricted. This limits decreases in
the amount of fluid that would be caused by, for example, a
reversed flow.
[0088] The liquid reservoir 52 that is capable of storing the
washer liquid drawn through the liquid inlet 51e is located between
the tapered hole 51c and the discharge port 53. Thus, by
accumulating washer liquid beforehand in the liquid reservoir
before the discharge valve 25 opens, the washer liquid may be mixed
with air in a favorable manner.
[0089] The holding valve 55 is located in a portion of the liquid
reservoir 52 proximate to the discharge port 53. The holding valve
55 prevents the outflow of washer liquid from the discharge port 53
when the discharge valve 25 is closed, and opens when the discharge
valve 25 opens. This prevents the outflow of washer liquid from the
discharge port 53 before the discharge valve 25 opens and ensures
that air is mixed with the washer liquid.
[0090] Further, the tapered hole 51c, the discharge port 53, and
the liquid reservoir 52 are arranged along a straight line. Thus,
less pressure is lost compared to when, for example, the tapered
hole 51c, the liquid reservoir 52, and the discharge port 53 are
arranged in a curved layout.
[0091] This example (refer to FIGS. 11 to 14) includes the fluid
check valve 54. However, the fluid check valve 54 is not necessary.
Further, this example includes the liquid reservoir 52. However,
the liquid reservoir 52 is not necessary. Moreover, this example
includes the holding valve 55. However, the holding valve 55 is not
necessary. For example, the washer pump 88 may be driven when
opening the discharge valve 25. Such a structure allows fluid,
which is a mixture of the washer liquid and air, to be discharged
(ejected) from the discharge port 53.
[0092] Further, in this example, the tapered hole 51c (valve port),
the liquid reservoir 52, and the discharge port 53 are arranged
along a straight line. However, the tapered hole 51c, the liquid
reservoir 52, and the discharge port 53 may be arranged in a curved
layout.
[0093] In this example, the holding valve 55 opens if the pressure
of the liquid reservoir 52 suddenly increases when the discharge
valve 25 opens. Instead, for example, as shown in FIG. 15, the
discharge valve 25 may include an operation rod 25c to operate
(push) the holding valve 55 when the discharge valve 25 opens. This
opens the holding valve 55.
[0094] In the above embodiment, the air pump 85 (discharge port 24)
and the nozzle unit 8 (nozzle 11) are simply connected by the hose
84. Instead, for example, the air pump 85 and the nozzle unit 8 may
be connected by a mixing member including a liquid inlet allowing
for washer liquid to be drawn in.
[0095] For example, a modification may be made as shown in FIG. 16.
The on-board optical sensor cleaning device of this example
includes the air pump 85, which serves as the electric pump in the
above embodiment, and the nozzle 11 (nozzle unit 8). A mixing
member 61 connects the discharge port 24 (air pump 85) and the
nozzle 11 (nozzle unit 8).
[0096] The mixing member 61 includes a line communicating the
discharge port 24 and the nozzle 11. The line includes a liquid
reservoir 61a that is able to store washer liquid with gravity. The
mixing member 61 includes a liquid inlet 61b through which washer
liquid can be drawn at a position corresponding to the liquid
reservoir 61a. A fluid check valve 62 connects the liquid inlet 61b
to the washer pump 88 to permit the entrance of washer liquid and
prevent a reversed flow of fluid.
[0097] This allows for the ejection of fluid, which is a mixture of
the washer liquid and air, from the ejection port 11a of the nozzle
11 (refer to FIG. 5) in the same manner as the above example (refer
to FIGS. 11 to 14). Thus, the lens 5c (refer to FIG. 1) may be
cleaned in a favorable manner.
[0098] In this example (refer to FIG. 16), the washer pump 88 is
driven at the same time as when the air pump 85 (motor 23) is
driven and controlled to deliver the washer liquid into the liquid
reservoir 61a before the discharge valve 25 opens.
[0099] Specifically, for example, as shown in FIG. 17, when a
switch in the vehicle is operated (ON), the washer pump 88 is
driven (ON) at the same time as when the air pump 85 (motor 23) is
driven (ON). The washer pump 88 delivers a preset amount of washer
liquid to the liquid reservoir 61a before when the discharge valve
25 opens at time Ta, that is, before the pressure and velocity in
the cylinder becomes maximal. In FIG. 17, when the air pump 85 goes
on, the motor 23 produces forward rotation to move forth the piston
22.
[0100] As a result, the air pump 85 (motor 23) is readily driven,
and the washer liquid is accumulated in the liquid reservoir 61a
before the discharge valve 25 opens. This mixes the washer liquid
with air in a favorable manner. Thus, the delivery of the washer
liquid is performed (completed) when the piston 22 is compressing
the air in the cylinder 21. The time from when, for example, the
switch is operated to when ejection occurs may be shortened, and a
fluid obtained by mixing air and the washer liquid in a favorable
manner can be ejected.
[0101] The washer pump 88 may also be controlled to be driven for a
preset time before the air pump 85 (motor 23) is driven.
[0102] More specifically, for example, as shown in FIG. 18, when a
switch in the vehicle is operated (ON), the washer pump 88 is
driven (ON) for a preset time t1 before the air pump 85 (motor 23)
is driven. After the washer pump 88 is stopped, the air pump 85 is
driven (ON).
[0103] As a result, the air pump 85 (motor 23) is driven so that
the accumulation of the washer liquid in the liquid reservoir 61a
is further ensured before the discharge valve 25 opens, and the
washer liquid is mixed with air in a favorable manner.
[0104] Further, the washer pump 88 may be controlled to be driven
for a preset time after the discharge valve 25 opens.
[0105] More specifically, for example, as shown in FIG. 19, when a
switch in the vehicle is operated (ON), the air pump 85 (motor 23)
is driven (ON) and the discharge valve 25 opens. After the
discharge valve 25 opens, the washer pump 88 is driven (ON) for a
preset time t2.
[0106] As a result, after ejecting fluid (washer liquid and air)
from the ejection port 11a of the nozzle 11, the washer liquid can
be accumulated in the liquid reservoir 61a. Thus, when fluid
(washer liquid and air) is ejected from the ejection port 11a of
the nozzle 11 the next time, the washer liquid may be mixed with
air even when readily driving the air pump 85 (motor 23). Such
controls (refer to FIGS. 17 to 19) may be executed in the same
manner on the electric pump 86 of the above examples (FIGS. 11 to
15).
[0107] In the above embodiment, the air pump 85 includes a
mechanism that converts the rotational motion, which is produced by
the motor 23, to linear motion with the screw effect. The air pump
85 may further include a speed reduction mechanism that reduces the
speed of the rotation produced by the motor and transmitted to the
piston.
[0108] FIG. 20 shows an example of an air pump 85 that includes a
speed reduction mechanism. A large-diameter gear 71 is fitted and
fixed onto the male screw 32. A small-diameter gear 73 is fitted
and fixed onto a rotation shaft 72a of a motor 72. The
large-diameter gear 71 and the small-diameter gear 73 are engaged
with each other. In this example, the large-diameter gear 71 and
the small-diameter gear 73 form the speed reduction mechanism.
Further, in this example, a piston 74 does not include a female
screw 22a extending through the piston 74 like in the above
embodiment but includes a tube 74a extending outside the cylinder
21 (pump chamber). The inner circumferential surface of the tube
74a forms a female screw 74b, which is engaged with the male screw
32.
[0109] As a result, the speed reduction mechanism (large-diameter
gear 71 and small-diameter gear 73) allows the size of the motor
(output reduction) to be reduced.
[0110] In the above embodiment, the motor 23 (rotation shaft 23a)
is driven in a direction that is opposite to when moving the piston
22 forth in order to move the piston 22 back and enlarge the void
(pump chamber) in the cylinder 21. Instead, the piston 22 may be
moved back by the biasing force of a back movement biasing member
(coil spring or the like). As a result, when the motor 23 is
deactivated, the biasing force of the biasing member moves back the
piston and returns the air pump 85 to the standby state.
[0111] In the above embodiment and examples, the air pump 85 and
the electric pump 86 are parts of the on-board optical sensor
cleaning device. Instead, the air pump 85 and the electric pump 86
may be used as an air pump and an electric pump used for a device
other than the on-board optical sensor cleaning device. Further, in
the above embodiment, the on-board optical sensor is the on-board
camera 5 that captures images at the rear of the vehicle 1.
Instead, for example, the on-board optical sensor may be an
on-board camera that captures images from the vehicle 1 in other
directions. Further, the on-board optical sensor may be a rain
sensor or the like used by a CPU or the like to check the amount of
rain based on a captured image.
* * * * *