U.S. patent application number 09/861515 was filed with the patent office on 2001-11-29 for hydraulic circuit cleaning apparatus and method.
This patent application is currently assigned to TOYOTA JIDOSHA KABUSHIKI KAISHA. Invention is credited to Habuchi, Ryoji, Kasuga, Shinji, Morioka, Hiroshi, Soga, Yoshinobu, Yasue, Hideki.
Application Number | 20010045221 09/861515 |
Document ID | / |
Family ID | 18656125 |
Filed Date | 2001-11-29 |
United States Patent
Application |
20010045221 |
Kind Code |
A1 |
Soga, Yoshinobu ; et
al. |
November 29, 2001 |
Hydraulic circuit cleaning apparatus and method
Abstract
A hydraulic circuit cleaning apparatus has a hydraulic circuit
that includes an oil pump, an oil passage to which the oil pressure
ejected from the oil pump is supplied, and a pressure regulator
device connected to the oil passage for regulating the oil pressure
in the oil passage. The apparatus cleans the hydraulic circuit by
using a cleaning liquid. A discharge oil passage is connected to a
discharge port of the pressure regulator device, so that the
cleaning liquid is discharged out of the hydraulic circuit via the
discharge oil passage.
Inventors: |
Soga, Yoshinobu;
(Toyota-shi, JP) ; Habuchi, Ryoji; (Okazaki-shi,
JP) ; Morioka, Hiroshi; (Toyota-shi, JP) ;
Kasuga, Shinji; (Anjo-shi, JP) ; Yasue, Hideki;
(Toyota-shi, JP) |
Correspondence
Address: |
OBLON SPIVAK MCCLELLAND MAIER & NEUSTADT PC
FOURTH FLOOR
1755 JEFFERSON DAVIS HIGHWAY
ARLINGTON
VA
22202
US
|
Assignee: |
TOYOTA JIDOSHA KABUSHIKI
KAISHA
TOYOTA-SHI
JP
|
Family ID: |
18656125 |
Appl. No.: |
09/861515 |
Filed: |
May 22, 2001 |
Current U.S.
Class: |
134/22.1 ;
475/116 |
Current CPC
Class: |
F16H 57/0408 20130101;
F16H 57/0489 20130101; F16H 61/0021 20130101; F16H 57/0402
20130101 |
Class at
Publication: |
134/22.1 ;
475/116 |
International
Class: |
B08B 009/00; F16H
031/00 |
Foreign Application Data
Date |
Code |
Application Number |
May 22, 2000 |
JP |
2000-150404 |
Claims
What is claimed is:
1. A hydraulic circuit cleaning apparatus coupled to a hydraulic
circuit, comprising: an oil pump, an oil passage to which oil
ejected from the oil pump is supplied, and a pressure regulator
device that is disposed in the oil passage and that regulates the
pressure of the oil in the oil passage, the pressure regulator
device having a discharge port for discharging oil to the oil
passage, a discharge passage that is connected to the discharge
port and that is adapted to discharge a cleaning liquid out of the
hydraulic circuit.
2. A cleaning apparatus according to claim 1, further comprising a
lid member that closes the discharge passage.
3. A cleaning apparatus according to claim 2, wherein the discharge
passage is closed by the lid member after the cleaning liquid flows
through the hydraulic circuit and is discharged from the discharge
passage.
4. A cleaning apparatus according to claim 1, wherein the oil pump
has a suction opening, wherein the discharge port of the pressure
regulator device is connected to the suction opening of the oil
pump, and wherein the discharge passage is provided in a path from
the discharge port to the suction opening of the oil pump.
5. A cleaning apparatus according to claim 1, wherein the pressure
regulator device is adapted to connect the oil passage and the
discharge passage in communication when a pressure in the oil
passage is at least a predetermined pressure.
6. A hydraulic circuit cleaning apparatus in a hydraulic circuit
comprising: a oil pump having an ejection opening for ejecting oil
and a suction opening for sucking oil; a circulating oil passage
that is connected to the ejection opening and to the suction
opening; a pressure regulator device that is disposed in the
circulating oil passage and that regulates at least the pressure of
the oil at an ejection side of the oil pump; and a discharge
passage that is connected between the pressure regulator device in
circulating oil passage and the suction opening of the oil pump and
that is adapted to discharge the cleaning liquid.
7. A cleaning apparatus according to claim 6, further comprising a
sealing member that closes the discharge passage.
8. A cleaning apparatus according to claim 7, further comprising a
filtering device that filters an oil sucked into the suction
opening of the oil pump, wherein the sealing member is a plug that
is inserted into the discharge passage to close the discharge
passage, and wherein the filtering device is constructed so as to
prevent the plug from falling from the discharge passage.
9. A cleaning method for cleaning a hydraulic circuit including an
oil pump that sucks oil via a suction port and that ejecting the
oil to a passage via an ejection port, a pressure regulator device
that is connected to the ejection port and that regulates the oil
pressure in the passage, the pressure regulator device having a
discharge port for discharging the pressure regulated oil, and an
oil passage connecting the suction port of the oil pump and the
discharge port of the pressure regulator device, the cleaning
method comprising: injecting a cleaning liquid into the hydraulic
circuit; supplying the cleaning liquid to the pressure regulator
device via the oil pump; and discharging the cleaning liquid from
the oil passage.
10. A transmission that controls a speed shift via an oilamount,
comprising: a speed changing mechanism that performs the speed
shift upon being supplied with an oil from an oil passage for
changing between at least two speed shift clutches; and a hydraulic
circuit cleaning apparatus comprising a discharge passage that is
connected to a discharge port of a pressure regulator device and
that is adapted to discharge a cleaning liquid out of the hydraulic
circuit; and a controller that controls an oil amount supplied to
the speed changing mechanism via the hydraulic circuit.
Description
INCORPORATION BY REFERENCE
[0001] The disclosure of Japanese Patent Application No.
2000-150404 filed on May 22, 2000 including the specification,
drawings and abstract is incorporated herein by reference in its
entirety.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to a cleaning apparatus and a
cleaning method for removing foreign substances from a hydraulic
circuit.
[0004] 2. Description of the Related Art
[0005] Generally, in a vehicle equipped with an automatic
transmission, a hydraulic control apparatus and an electronic
control apparatus are provided. The hydraulic control apparatus
includes a hydraulic circuit provided with oil passages for
supplying and discharging oil pressure with respect to operation
mechanisms of the automatic transmission, and various valves for
controlling the opening and closing of the oil passages and the oil
pressure in the oil passages. The electronic control apparatus is
formed by a microcomputer. Various kinds of data are pre-stored in
the electronic control apparatus. The electronic control apparatus
is designed so that signals from various sensors and switches are
inputted to the electronic control apparatus.
[0006] The electronic control apparatus makes determinations
regarding the control of the transmission speed ratio based on the
signals from the various sensors and switches and the
aforementioned data, and outputs a control signal based on a result
of the determination to the hydraulic control apparatus. As a
result, the supplying/discharging of oil pressure with respect to
the operational mechanisms and the oil pressure supplied thereto
are controlled so as to control the speed ratio of the automatic
transmission. The oil pressure supplied to the hydraulic circuit is
generated by a pressure regulator device regulating the pressure
ejected from an oil pump.
[0007] A hydraulic circuit as mentioned above is formed by a
component part termed a "valve body". Such a valve body is mounted
between an oil pan and a casing forming an outer shell of the
automatic transmission. However, before the valve body is mounted
between the casing and the oil pan, the hydraulic circuit is
usually cleaned since there is a possibility of contamination of an
interior of the hydraulic circuit with foreign substances.
[0008] As an art related to the hydraulic circuit cleaning
apparatus as mentioned above, Japanese Patent Application Laid-Open
No. HEI 10-37734 describes an example of the method for cleaning an
oil supplying apparatus and a lubricant supplying apparatus used in
a lubrication system of an electric power generating steam turbine,
an electric power generator, etc. This laid-open patent application
describes a normal-use oil pump provided in an oil tank, two oil
coolers, and six nozzles that are opened and closed by an oilcooler
switching valve. The patent application further describes a
flushing oil pump connected to a circuit of the oil tank, and a
plurality of valves for opening and closing an oil passage between
the circuit and the flushing pump. Oil supplied from the normal-use
oil pump is supplied to an inlet of one of the two oil coolers, and
is thereby cooled. After that, oil is discharged from an outlet of
the oil cooler, and is delivered to a bearing supply line.
Furthermore, using oil ejected from the flushing oil pump, the oil
passage in the oil tank can be cleaned.
[0009] The method of cleaning an oil supplying apparatus described
in the aforementioned patent application is one in which an oil
passage provided in the oil tank is flushed. However, the patent
application does not describe the cleaning of a hydraulic circuit
that includes an oil pump and apressure regulating device.
SUMMARY OF THE INVENTION
[0010] The invention has been accomplished in view of the
aforementioned circumstances. The invention provides an apparatus
and a method for cleaning hydraulic circuit which are capable of
cleaning a hydraulic circuit that is provided with an oil pump, a
pressure regulator device, etc.
[0011] A hydraulic circuit cleaning apparatus in accordance with a
first mode of the invention includes a hydraulic circuit, and a
discharge passage that discharges from the hydraulic circuit a
cleaning liquid provided for cleaning the hydraulic circuit. The
hydraulic circuit includes an oil pump, an oil passage to which an
oil pressure ejected from the oil pump is supplied, and a pressure
regulator device that is connected to the oil passage and that
regulates the oil pressure in the oil passage. The discharge
passage is connected to a discharge port of the pressure regulator
device, and discharges the cleaning liquid out of the hydraulic
circuit.
[0012] According to the first mode, when the cleaning liquid is
delivered into the oil passage of the hydraulic circuit, the
cleaning liquid is discharged into the discharge oil passage via
the discharge port of the pressure regulator device. Then, the
cleaning liquid is discharged from the discharge oil passage via
the discharge passage. Therefore, the cleaning liquid containing
foreign substances is not returned to the hydraulic circuit.
Therefore, the interior of the hydraulic circuit can be cleaned by
utilizing the discharge oil passage connected to the pressure
regulator device.
[0013] The above-described cleaning apparatus may further include a
lid member that closes the discharge passage after the hydraulic
circuit is cleaned with the cleaning liquid.
[0014] If the cleaning liquid discharge passage is closed with the
lid member after the hydraulic circuit is cleaned, the oil
delivered into the oil passage by the oil pump will not be
discharged from the cleaning liquid discharge passage.
[0015] The cleaning apparatus of the first mode may be constructed
so that the oil pressure discharged from the discharge port of the
pressure regulator device is supplied to the suction opening of the
oil pump when the oil pump sucks the oil, provided that the
discharge passage is closed with the lid member after the hydraulic
circuit has been cleaned.
[0016] A hydraulic circuit cleaning apparatus in accordance with a
second mode of the invention includes a hydraulic circuit, and a
discharge passage that discharges from the hydraulic circuit a
cleaning liquid for cleaning the hydraulic circuit. The hydraulic
circuit includes an oil pump, a circulating oil passage, and a
pressure regulator device disposed in the circulating oil passage
for regulating the oil pressure in the oil passage. The discharge
passage is connected between the pressure regulator device in the
circulating oil passage and the suction opening of the oil pump,
and discharges the cleaning liquid out of the hydraulic
circuit.
[0017] According to the second mode, when the cleaning liquid is
delivered into the oil passage of the hydraulic circuit, the
cleaning liquid is delivered to the circulating oil passage, and is
discharged from the discharge passage via the pressure regulator
device. Therefore, the cleaning liquid contaminated with foreign
substances will not be returned into the hydraulic circuit. Hence,
the interior of the hydraulic circuit can be cleaned by simply
utilizing the discharge oil passage connected to the pressure
regulator device.
[0018] The cleaning apparatus of the second mode may further
include a sealing member that closes the discharge passage, and the
hydraulic circuit may further include a filtering device that
filters oil sucked into the suction opening of the oil pump.
[0019] The filtering device may be constructedso as to also perform
the function of preventing the plug from falling apart. In that
case, it is unnecessary to provide a separate member for preventing
the plug from falling apart.
[0020] In a cleaning method for cleaning a hydraulic circuit in
accordance with a third mode of the invention, the hydraulic
circuit includes an oil pump, an oil passage connected to a suction
port of the oil pump, a pressure regulator device that is connected
to the oil passage and that regulates the oil pressure in the oil
passage, and a discharge oil passage connecting a discharge port of
the pressure regulator device and the suction port of the oil pump,
and the cleaning liquid used to clean the hydraulic circuit is
discharged via the discharge oil passage.
[0021] According to the third mode, the cleaning liquid used to
clean the hydraulic circuit is discharged out of the hydraulic
circuit via the discharge oil passage. Therefore, the method
prevents the cleaning liquid contaminated with foreign substances
from circulating in the hydraulic circuit. Hence, the method makes
it possible to clean the interior of the hydraulic circuit by using
the discharge oil passage connected to the pressure regulator
device.
BRIEF DESCRIPTION OF THE DRAWINGS
[0022] The foregoing and further objects, features and advantages
of the present invention will become apparent from the following
description of preferred embodiments with reference to the
accompanying drawings, wherein like numerals are used to represent
like elements and wherein:
[0023] FIG. 1 is a schematic diagram illustrating a portion of a
hydraulic circuit of a belt-type continuously variable transmission
to which the invention is applied;
[0024] FIG. 2 is a skeleton diagram illustrating a power
transmission path of an FF vehicle to which the invention is
applied;
[0025] FIG. 3 is a block diagram illustrating a control system of
the vehicle shown in FIG. 2;
[0026] FIG. 4 is an exploded perspective view of some of the
components of atransaxle shown in FIG. 2;
[0027] FIG. 5 is a sectional view more specifically illustrating
the construction shown in FIG. 1;
[0028] FIG. 6 is a schematic diagram illustrating acleaning method
of a hydraulic circuit to which the invention is applied; and
[0029] FIG. 7 is a schematic diagram of still another construction
of an hydraulic circuit to which the invention is applied.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
[0030] The preferred embodiments of the invention will hereinafter
be described in detail with reference to the attached drawings.
FIG. 2 is a skeleton diagram showing a front-engine, front-drive
vehicle to which this invention is applied. Referring to FIG. 2, an
engine 1 is installed as a power source for a vehicle. An internal
combustion engine, more particularly a gasoline engine, diesel
engine, oran LPG engine, may used as the engine 1. A crankshaft 2
of the engine 1 is disposed in the width direction of the vehicle.
For the sake of convenience, the following description assumes that
a gasoline engine is used as the engine 1.
[0031] A transaxle 3 is provided on the output side of the engine
1. The transaxle 3 has a transaxle housing 4, a transaxle case 5,
and a transaxle cover 6. The transaxle housing 4 is attached to the
rear end of the engine 1. The transaxle case 5 is mounted on the
end of an opening in the transaxle housing 4 opposite the engine 1.
The transaxle cover 6 is mounted on the end of an opening in the
transaxle case 5 opposite the transaxle housing 4. A valve body
unit and an oil pan are attached to a lower portion of the
transaxle case 5.
[0032] A torque converter 7 is provided inside the transaxle
housing 4. A forward-reverse selection mechanism 8, variable belt
transmission (CVT) 9, and a final reduction gear (in other words, a
differential gear system) 10 are provided inside the transaxle case
6 and the transaxle rear cover 6. The construction of the torque
converter 7 will first be described. An input shaft 11 that can
rotate about the same axis as the crankshaft 2 is provided in the
transaxle housing 4. A turbine runner 13 is mounted on the end of
the input shaft 11 on the side of the engine 1.
[0033] A front cover 15 is communicated via a drive plate 14 to the
rear end of the crankshaft 2 and a pump impeller 15 is connected to
the front cover 15. The turbine runner 13 and the pump impeller 16
are disposed opposing one another and a stator 17 is provided
inside the turbine runner 13 and the pump impeller 16. A hollow
shaft 17B is connected by way of a one-way clutch 17A to the stator
17. The input shaft 11 runs through this hollow shaft 17B. A lockup
clutch 19 is provided via a damper mechanism 18 on the end of the
input shaft 11 on the side of the front cover 15. Oil as a
hydraulic fluid is supplied to the inside of a casing (not shown)
formed by the front cover 15, pump impeller 16, and other
components as noted above.
[0034] With this configuration, a power (torque) from the engine 1
is transmitted through the crankshaft 2 to the front cover 15. If
the lockup clutch 19 is disengaged at this time, torque of the pump
impeller 16 is transmitted to the turbine runner 13 and then to the
input shaft 11 through the fluid. The torque transmitted from the
pump impeller 16 to the turbine runner 13 may be amplified by the
stator 17. On the other hand, if the lockup clutch 19 is engaged at
this time, the torque of the front cover 15 is mechanically
transmitted to the input shaft 11.
[0035] An oil pump 20 is provided between the torque converter 7
and the forward-reverse selection mechanism 8. A rotor 21 of the
oil pump 20 and the pump impeller 16 are connected by a hub 22 of
cylindrical shape. A body 23 of the oil pump 20 is secured to a
side of the transaxle case 5. The hub 22 and the hollow shaft 17B
are in splined engagement with each other. This configuration
allows power from the engine 1 to be transmitted via the pump
impeller 16 to the rotor 21, thus driving the oil pump 20.
[0036] The forward-reverse selection mechanism 8 is provided along
a power transmission path between the input shaft 11 and the
variable belt transmission 9. The forward-reverse selection
mechanism 8 is provided with a planetary gear mechanism 24 of a
double-pinion type. The planetary gear mechanism 24 comprises a sun
gear 25 provided on the end of the input shaft 11 on the side of
the variable belt transmission 9, a ring gear 26 disposed
concentrically with the sun gear 25 on an outer peripheral side of
the sun gear 25, a pinion gear 27 that is meshed with the sun gear
25, a pinion gear 28 that is meshed with the pinion gear 27 and the
ring gear 26, and a carrier 29 which rotatably retains the pinion
gears 27 and 28, as well as retains the pinion gears 27 and 28 so
that they can rotate integrally around the sun gear 25. The carrier
29 is connected to a primary shaft (to be described later) of the
input shaft 11. In addition, a forward clutch CR, which connects
and disconnects a power transmission path between the carrier 29
and the input shaft 11, is provided. Further, a reverse brake BR,
which controls rotation and lockup of the ring gear 26, is provided
on a side of the transaxle case 5.
[0037] The variable belt transmission 9 is provided with a primary
shaft 30 disposed concentrically with the input shaft 11 (in other
words, a shaft on the drive side) and a secondary shaft 31 disposed
in parallel with the primary shaft 30 (in other words, a
countershaft or a shaft on the driven side). Bearings 32 and 33
rotatably retain the primary shaft 30 and bearings 34 and 35
rotatably retain the secondary shaft 31.
[0038] The primary shaft 30 is provided with a primary pulley 36
and the secondary shaft 31 is provided with a secondary pulley 37.
The primary pulley 36 is provided with a fixed sheave 38 (in other
words, a fixed member) formed integrally with the primary shaft 30
on its periphery and a movable sheave 39 (in other words, a movable
member) configured so as to be movable in an axial direction of the
primary shaft 30. A V-shaped groove 40 is formed between opposing
faces of the fixed sheave 38 and the movable sheave 39.
[0039] Furthermore, a hydraulic actuator 41 (in other words, a
hydraulic servo mechanism) that causes the movable sheave 39 to
approach and separate from the fixed sheave 38 by moving the
movable sheave 39 in the axial direction of the primary shaft 30 is
provided. Meanwhile, the secondary pulley 37 is provided with a
fixed sheave 42 (in other words, a fixed member) formed integrally
with the secondary shaft 31 on the periphery thereof and a movable
sheave 43 (in other words, a movable member) configured so as to be
movable in an axial direction of the secondary shaft 31. A V-shaped
groove 44 is formed between opposing faces of the fixed sheave 42
and the movable sheave 43. In addition, a hydraulic actuator 45 (in
other words, a hydraulic servo mechanism) that causes the movable
sheave 43 to approach and separate from the fixed sheave 42 by
moving the movable sheave 43 in the axial direction of the
secondary shaft 31 is provided.
[0040] A belt 46 is wound around the groove 40 of the primary
pulley 36 and the groove 44 of the secondary pulley 37 in the
configuration. The belt 46 is provided with multiple metal blocks
and a plurality of steel rings. A counter driven gear 47 of a
cylindrical shape is secured to the secondary shaft 31 on the side
of the engine 1 and the counter driven gear 47 is retained by
bearings 48 and 49. The bearing 35 is provided on the side of the
transaxle rear cover 6 and a parking gear 31A is provided on the
secondary shaft 31 between the bearing 35 and the secondary pulley
37.
[0041] An intermediate shaft 50 that is parallel with the secondary
shaft 31 is provided along a power transmission path between the
counter driven gear 47 and the final reduction gear 10 of the
variable belt transmission 9. The intermediate shaft 50 is
supported by bearings 51 and 52. A counter driven gear 53 and a
final drive gear 54 are formed on the intermediate shaft 50. The
counter drive gear 47 is meshed with the counter driven gear
53.
[0042] The final reduction gear 10 is provided with a hollow
differential case 55. The differential case 55 is rotatably
retained by bearings 56 and 57 and a ring gear 58 is provided on an
outer periphery of the differential case 55. The final drive gear
54 is meshed with the ring gear 58. A pinion shaft 59 is mounted
inside the differential case 55 and two pinion gears 60 are mounted
on the pinion shaft 59. Two side gears 61 are meshed with these
pinion gears 60. A front drive shaft 62 is connected independently
to each of the two side gears 61 and a wheel (front wheel) 63 is
connected to each of these front drive shafts 62.
[0043] FIG. 3 is a block diagram showing a control system of the
vehicle shown in FIG. 2. An electronic control unit 64 that
controls the entire vehicle is made up of a microprocessor
comprising mainly a computer processing unit (CPU or MPU), storage
devices (RAM and ROM), and an I/O interface.
[0044] Signals are input to this electronic control unit 64 from
such devices as an engine speed sensor 65, an accelerator opening
sensor 66, a throttle opening sensor 67, a brake switch 68, a shift
position sensor 69 that detects the operating condition of a shift
position selection unit 69A, an input speed sensor 70 that detects
the input speed of the variable belt transmission 9, an output
speed sensor 71 that detects the output speed of the variable belt
transmission 9, an oil temperature sensor 72 that detects the
hydraulic fluid temperature of the variable belt transmission 9 and
the torque converter 7, an air conditioner switch 73, and a coolant
temperature sensor 74 that detects coolant temperature of the
engine 1.
[0045] The signal fed from the shift position sensor 69 is used to
determine which is selected, either a drive position [for example,
D (drive) position, R (reverse) position, etc.] or a non-drive
position [for example, N (neutral) position, P (park) position,
etc.]. It is further used to determine which is selected of the two
drive positions, either a forward position (for example, D
position) or a reverse position (R position). Furthermore, a
vehicle speed and a gear ratio of the variable belt transmission 9
can be calculated by using a signal from the engine speed sensor
65, a signal from the input speed sensor 70, and a signal from the
output speed sensor 71 and the like.
[0046] The electronic control unit 64 outputs a signal that
controls a fuel injection control unit 75 of the engine 1, a signal
that controls an ignition timing control unit 76 of the engine 1,
and a signal that controls a hydraulic pressure control unit 77. A
construction of the hydraulic pressure control unit 77 will be
described. FIG. 4 is an exploded view of some of the component
parts of the transaxle 3. An oil pan 80 is attached to a lower
portion of the transaxle case 5. A valve body unit 84 formed by
integrally assembling an upper valve body 81, a plate 82 and a
lower valve body 83 are provided between the transaxle case 5 and
the oil pan 80. The valve body unit 84 forms a hydraulic
circuit.
[0047] FIG. 1 is a schematic diagram illustrating a portion of a
hydraulic circuit 85 formed by the valve body unit 84. FIG. 5 is a
sectional view of specific component parts forming the hydraulic
circuit 85 shown in FIG. 1. A strainer 87 is provided in a path
extending from the oil pan 80 to a suction opening 86 of the oil
pump 20. A construction for mounting the strainer 87 will be
specifically described. A passage 101 is formed in the lower valve
body 83. The passage 101 connects to the side of the suction
opening 86.
[0048] The strainer 87 is formed by disposing two divisions 87A,
87B in a vertical positional relationship and integrally joining
the divisions. A division 87A is disposed above the other division
87B. The division 87A has a cylindrical ejection portion 102 that
is protruded toward the lower valve body 83. A cylindrical suction
portion 102A is protruded toward the oil pan 80. An outer
peripheral surface of the ejection portion 102 is fitted to an
inner peripheral surface of the passage 101. Due to this fitting
force, the strainer 87 is secured to the lower valve body 83. An
O-ring 103 is attached to an outer periphery of the ejection
portion 102, thus providing a liquid-tight seal between the
ejection portion 102 and the lower valve body 83.
[0049] An oil transportation path 20A connecting the suction
opening 86 and an ejection opening 88 is formed in the oil pump 20.
An oil passage 89 is connected to the ejection opening 88. The oil
passage 89 is also connected to an oil chamber (not shown) of a
hydraulic actuator 41.
[0050] The hydraulic circuit 85 is also provided with a pressure
regulator valve 90. The pressure regulator valve 90 has a pressure
regulation port 91 and a discharge port 92. An oil passage 89A
branching from an intermediate portion of the oil passage 89 is
connected to the pressure regulation port 91. The pressure
regulator valve 90 has a known construction provided with a spool
(not shown), a spring (not shown), etc. The pressure regulator
valve 90 is used for controlling the oil pressure at the ejection
side of the pressure regulator valve 90. The pressure regulation
port 91 and the hydraulic actuator 41 are disposed in parallel.
[0051] A discharge oil passage (in other words, a relief oil
passage or a circulating oil passage) 93 is formed connecting the
discharge port 92 and the suction opening 86 of the oil pump 20.
The discharge oil passage 93 is provided with a cleaning liquid
discharge passage 95 that connects to the side of the oil pan
80.
[0052] As shown in FIG. 5, the cleaning liquid discharge passage 95
extends substantially vertically through the lower valve body 83.
The cleaning liquid discharge passage 95 is formed above the
strainer 87. A plug 96 is provided for opening and closing the
cleaning liquid discharge passage 95. The plug 96 has a shaft
portion 97 and a head portion 98. An O-ring 99 is attached to an
outer periphery of the shaft portion 97. The shaft portion 97 of
the plug 96 is fitted into the cleaning liquid discharge passage 95
from the side of the oil pan 80. The strainer 87 contacts a lower
surface of the head portion 98 of the plug 96 fitted to the lower
valve body 83.
[0053] The valve body unit 84 has a solenoid valve (not shown) for
controlling the engagement and disengagement of the lockup clutch
19, a solenoid valve (not shown) for controlling the oil pressure
supplied and discharged with respect to the oil chambers of the
hydraulic actuators 41, 45, a solenoid (not shown) for controlling
the oil pressure that acts on the forward clutch CR and the reverse
brake BR, etc. The hydraulic circuit 85 is further provided with an
oil passage (not shown) that connects to the hydraulic actuator
45.
[0054] Data used for providing a transmission control of the engine
1, lockup clutch 19, and the variable belt transmission 9 based on
the various signals are stored in the electronic control unit 64.
For example, the electronic control unit 64 stores data, with which
an optimum operating condition of the engine 1 is selected by
controlling the gear ratio of the variable belt transmission 9
based on the accelerator opening, vehicle speed, and other vehicle
operating conditions. The electronic control unit 64 also stores a
lockup clutch control map having the accelerator opening and
vehicle speed as parameters. The lockup clutch 19 is controlled
through each state of engagement, disengagement, and slip based on
this lockup clutch control map. The electronic control unit 64
outputs control signals to the fuel injection control unit 75, the
ignition timing control unit 76, and the hydraulic pressure control
unit 77 based on the various signals input to the electronic
control unit 64 and the data stored in the electronic control unit
64.
[0055] The corresponding relationships between the construction of
this embodiment and the construction of the invention will now be
described. The oil passage 89 corresponds to an oil passage in the
invention. The pressure regulator valve 90 corresponds to a
pressure regulator device in the invention. The plug 96 corresponds
to a lid member and a sealing device in the invention. The oil
passage 89, 89A and the discharge oil passage 93 correspond to a
circulating oil passage in the invention. The strainer 87
corresponds to a filtering device in the invention.
[0056] An example of control content of a vehicle of this
configuration will hereinafter be described. The forward-reverse
selection mechanism 8 is controlled based on operation of the shift
position selection unit 69A. When a forward position is selected,
the forward clutch CR is engaged and the reverse brake BR is
released, which results in the input shaft 11 being directly
connected to the primary shaft 30. When the torque (or power) of
the engine 1 is transmitted via the torque converter 7 to the input
shaft 11 in this state, the input shaft 11, carrier 29, and the
primary shaft 30 turn integrally. The torque of the primary shaft
30 is transmitted via the primary pulley 36, the belt 46, and the
secondary pulley 37 to the secondary shaft 31.
[0057] The torque transmitted to the secondary shaft 31 is
transmitted to the intermediate shaft 50 by way of the counter
drive gear 47 and the counter driven gear 53. The torque
transmitted to the intermediate shaft 50 is transmitted to the
differential case 55 by way of the final drive gear 54 and the ring
gear 58. When the differential case 55 turns, its torque is
transmitted to the drive shaft 62 by way of the pinion gear 60 and
the side gear 61, and then transmitted to the wheel 63.
[0058] When the reverse position is selected, on the other hand,
the forward clutch CR is disengaged and the reverse brake BR is
engaged, thus locking the ring gear 26. Then, as the input shaft 11
turns, the pinion gears 27 and 28 rotate while they rotate on their
own axes. The carrier then rotates in a direction opposite the
direction of rotation of the input shaft 11. As a result, the
primary shaft 30, secondary shaft 31, intermediate shaft 50, and so
forth rotate in a direction opposite that of when a forward
position is selected, allowing the vehicle to reverse.
[0059] The gear ratio of the variable belt transmission 9 is
controlled so that the operating conditions of the engine 1 may be
optimized based on vehicle acceleration requirements evaluated with
the vehicle speed, accelerator opening, and other conditions
(namely, drive power requirements), data stored in the electronic
control unit 64 (for example, an optimum fuel consumption curve
having the engine speed and throttle opening as parameters), and
other factors. To be more specific, the width of the groove 40 in
the primary pulley 36 is varied by controlling the hydraulic
pressure of the hydraulic chamber of the hydraulic actuator 41. As
a result, the winding radius of the belt 4 of the primary pulley 36
is changed, which means that the ratio of the input speed to the
output speed of the variable belt transmission 9, namely the gear
ratio, is controlled steplessly (continuously).
[0060] Furthermore, by controlling the oil pressure in the oil
chamber of the hydraulic actuator 45, the width of the groove 44 of
the secondary pulley 37 is changed. That is, the clamping pressure
(i.e., clamping force) of the secondary pulley 37 on the belt 31 in
the direction of the axis thereof is controlled. Based on the
clamping pressure, the tension of the belt 31 is controlled so that
the contact surface pressure between the primary pulley 36 and the
belt 31 and between the secondary pulley 37 and the belt 31 is
controlled. The oil pressure in the oil chamber of the hydraulic
actuator 45 is controlled based on the torque input to the variable
belt transmission 9, the speed ratio of the variable belt
transmission 9, etc. The torque input to the variable belt
transmission 9 is determined based on the engine revolution speed,
the degree of throttle opening, the torque ratio of the torque
converter 7, etc.
[0061] Next described will be a flushing operation of cleaning the
hydraulic circuit 85 of the valve body unit 84. During a process
preceding the mounting of the valve body unit 84 between the
transaxle case 5 and the oil pan 80 (i.e., a process before
shipment of the transaxle 3 from a factory), a flushing operation
of cleaning the interior of the hydraulic circuit 85 is performed
to remove foreign substances, for example, waste, dust, or the
like, which may be present within the hydraulic circuit 85.
[0062] To perform the flushing operation, an oil pump 100, separate
from the oil pump 20, is provided between the strainer 87 and the
oil pan 80 as shown in FIG. 6, and the plug 96 is removed to open
the cleaning liquid discharge passage 95. Then, using the oil pump
100, a cleaning liquid (which may be an automatic transmission
fluid (ATF) that is the operating fluid of the transaxle 3) is
supplied from the oil pan 80 into the hydraulic circuit 85. The
cleaning liquid is pumped into the oil passage 89, and the pressure
in the oil passage 89 rises to a predetermined pressure. Then, via
the pressure regulator valve 90, the pressure regulation port 91
and the discharge port 92 are connected in communication, so that
the cleaning liquid is discharged into the discharge oil passage 93
via the discharge port 92.
[0063] Since the cleaning liquid discharge passage 95 is opened as
mentioned above, the cleaning liquid is discharged from the
discharge oil passage 93 into the oil pan 80 via the cleaning
liquid discharge passage 95. Therefore, the cleaning liquid used to
remove foreign substances from the hydraulic circuit 85 will not
return to the hydraulic circuit 85. After the cleaning of the
hydraulic circuit 85 ends, the cleaning liquid discharge passage 95
is liquid-tightly closed by the plug 96 as shown in FIGS. 1 and 5,
and the oil pump 100 is removed.
[0064] Alternatively, the oil pump 20 and the pressure regulator
valve 90 can also be cleaned by driving the oil pump 20 and driving
the oil pump 100 after mounting the valve body unit 84 and the
strainer 87 below the transaxle case 5.
[0065] After the transaxle 3 is assembled, the ejection pressure of
the oil pump 20 is supplied to the oil passage 89. The oil pressure
in the oil passage 89 rises to a predetermined pressure. Then, via
the pressure regulator valve 90, the pressure regulation port 91
and the discharge port 92 are connected in communication, so that
oil is discharged from the pressure regulation port 91 into the
discharge oil passage 93 via the discharge port 92. Since the
cleaning liquid discharge passage 95 has been closed, the oil
pressure in the discharge oil passage 93 is transmitted to the
suction opening 86 of the oil pump 20. Thus, a circulating
operation occurs in which the oil pressure ejected from the
ejection opening 88 of the oil pump 20 is supplied back to the
suction opening 86 of the oil pump 20 via the pressure regulator
valve 90 and the discharge oil passage 93. That is, it can be said
that the discharge oil passage 93 forms a super charge circuit.
[0066] FIG. 7 illustrates another embodiment of the hydraulic
circuit cleaning apparatus and cleaning method, showing a portion
of a hydraulic circuit 85. In the hydraulic circuit 85 shown in
FIG. 7, constructions substantially the same as those of the
embodiment shown in FIGS. 1 to 6 are represented by reference
characters which are the same as those used in FIGS. 1 to 6. Such
constructions will not be described again.
[0067] In FIG. 7, the hydraulic circuit 85 has two pressure
regulator valves 104, 108. The pressure regulator valve 104 has a
pressure regulation port 105 and a discharge port 106. The pressure
regulator valve 108 has a pressure regulation port 109 and a
discharge port 110. An oil passage 89A branching from an oil
passage 89 is connected to the pressure regulation port 105. The
discharge port 106 and the pressure regulation port 109 are
connected by an oil passage 107. The discharge port 110 is
connected to the side of a suction opening 86 of an oil pump 20 via
a discharge oil passage (i.e., a circulating oil passage a relief
oil passage) 93. Thus, the pressure regulator valve 104 and the
pressure regulator valve 108 are connected in series. An oil
passage 111 connecting the hydraulic actuator 41 and the oil
passage 107 is provided. In the hydraulic circuit 85 shown in FIG.
7, the pressure regulator valves 104, 108 correspond to a pressure
regulator device in the invention. The oil passages 89, 89A, 107,
93 correspond to a circulating oil passage in the invention.
[0068] When a cleaning liquid is injected via the suction opening
86 of the oil pump 20 of the hydraulic circuit 85 of FIG. 7 with
the plug 96 having been removed, the cleaning liquid reaches the
pressure regulator valve 104 via the oil passages 89, 89A, and is
discharged from the discharge port 106 of the pressure regulator
valve 104, and reaches the pressure regulator valve 108 via the oil
passage 107, and is discharged from the discharge port 110, and
reaches the discharge oil passage 93. The cleaning liquid is then
discharged from the discharge oil passage 93 into the oil pan 80
via the cleaning liquid discharge passage 95. Therefore, the
cleaning liquid used to clean the interior of the hydraulic circuit
85 will not circulate in the hydraulic circuit 85. Thus, the
hydraulic circuit 85 of this embodiment achieves substantially the
same advantages as those achieved by the hydraulic circuit 85 shown
in FIG. 1. Furthermore, after the plug 96 is attached to the
hydraulic circuit 85 shown in FIG. 7, the hydraulic circuit 85
achieves substantially the same advantages as those achieved by the
hydraulic circuit 85 shown in FIG. 1.
[0069] According to the embodiments shown in FIGS. 1 to 7, the
flushing operation can be performed after the transaxle 3 is
manufactured. Furthermore, after the flushing operation, the
suction force of the oil pump 20 is supplemented with the oil
pressure in the discharge oil passage 93, so that the oil suction
function of the oil pump 20 improves. That is, it becomes possible
to perform the flushing operation in a process after manufacture of
the transaxle 3, without degrading the effect of re-supplying oil
pressure to the suction opening 86 of the oil pump 20 (i.e., the
super charge effect).
[0070] Furthermore, according to the embodiments, when the strainer
87 is secured to the lower valve body 83 after the cleaning liquid
discharge passage 95 is closed by the plug 96, the strainer 87
contacts the head portion 98 of the plug 96 as shown in FIG. 5.
That is, the strainer 87 performs both the function of cleaning oil
supplied from the side of the oil pan 80 to the side of the
strainer 87 and the function of preventing the plug 96 from falling
from the lower valve body 83 (generally termed fall-apart
preventing function). Therefore, it is unnecessary to separately
provide a component part for preventing the plug 96 from falling.
Hence, the number of component parts required for the cleaning
apparatus is reduced, thereby allowing size and weight reductions
of the apparatus and curbing increases in the production cost of
the apparatus.
[0071] The foregoing embodiments are also applicable to automatic
transmissions other than the continuously variable belt
transmission, for example, an automatic transmission that has a
planetary gear mechanism and friction engagement devices, such as
clutches, brakes and the like, which are engaged and disengaged to
change the torque transmission path. That is, each embodiment can
be used as a hydraulic circuit cleaning apparatus for a hydraulic
control apparatus that controls the engagement and disengagement of
the friction engagement devices and the engagement pressure for the
devices.
[0072] Furthermore, each embodiment can also be used as a hydraulic
circuit cleaning apparatus for a hydraulic control apparatus of a
toroidal type continuously variable transmission. The toroidal type
continuously variable transmission refers to a continuously
variable transmission having a plurality of cone discs each of
which has a power transmission surface of an arcuate shape
corresponding to the shape of an outer peripheral surface of a
doughnut, and at least one power roller that contacts the power
transmission surfaces of the cone discs via a lubricant (traction
oil). By controlling the operation of the power roller through the
use of the hydraulic control apparatus, the radius of the contact
between the power roller and the power transmission surfaces is
controlled to control the transmission speed ratio. The cleaning
apparatus of each of the foregoing embodiments is applicable to the
hydraulic circuit of the hydraulic control apparatus for
controlling the power roller.
[0073] The foregoing embodiments are also applicable to vehicles
that employ drive power sources other then internal combustion
engines, for example, electric motors. The embodiments are also
applicable to vehicles that incorporate combinations of engines and
electric motors as drive power sources.
* * * * *