JP2011069463A - Air separation structure in automatic transmission - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an air separation structure in an automatic transmission, removing air in oil flowing in a communicating pipe and preventing the air from being supplied into a speed change mechanism. <P>SOLUTION: This automatic transmission 1 is constituted by providing a torque converter 11 and the speed change mechanism 21 which are separated from each other and providing an oil pump 12 to be driven by an engine on a torque converter 11 side to suck oil from an oil pan 24 on a speed change mechanism 21 side through the communicating pipe 14. This automatic transmission 1 includes: a separation chamber 30 formed on the halfway of the communicating pipe 14 between the oil pump 12 and the oil pan 24 to separate air from oil; an electric pump 60 for discharging air in the separation chamber 30; and a control means 40 for controlling the electric pump 60. While a power switch 42 for starting operation of the engine is ON and engine speed Ne is below threshold value rotational speed Nth prescribing the engine speed for achieving such flow velocity of oil that prevents air from being collected in the communicating pipe 14, the control means 40 operates the electric pump 60. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an air separation structure in an automatic transmission in which a torque converter and a transmission mechanism are separated and provided separately.

  The automatic transmission torque converter and the transmission mechanism are separated, and the torque converter is provided at the front of the vehicle together with the engine, and the transmission mechanism is provided at the rear of the vehicle together with the differential device to transmit power from the torque converter to the transmission mechanism. Patent Document 1 discloses an automatic transmission that is configured to perform via a propeller shaft that connects a torque converter and a transmission mechanism.

  In the automatic transmission disclosed in Patent Document 1, an oil pump provided on the torque converter side sucks oil in an oil pan on the transmission mechanism side through a communication pipe and pressurizes the sucked oil. After that, it is supplied as working oil to the fastening element of the transmission mechanism via another communication pipe.

Japanese Patent Laid-Open No. 2005-88795

In this automatic transmission, since the oil pump and the oil pan are located apart from each other, the length of the communication pipe for supplying the oil sucked from the oil pan to the oil pump is long. There are multiple bends along the way.
Therefore, fine bubbles (air) contained in the oil flowing in the communication pipe gradually gather while flowing in the communication pipe toward the oil pump to form a large mass of air, and the bent part of the communication pipe Or may stay in the upper part.

  The mass of air staying in the communication pipe may be drawn into the oil pump when the flow rate of the oil flowing in the communication pipe becomes high. When the lump of air drawn into the oil pump is supplied to the fastening element of the speed change mechanism, for example, the fastening hydraulic pressure is not secured and a shock may occur.

In an automatic transmission, since air bleeding using an air breather is generally performed, it is conceivable to use the air breather to remove air accumulated in the communication pipe.
However, when the oil pump is in operation, since the inside of the communication pipe is slightly under negative pressure, a mass of air that is slightly lower than the atmospheric pressure may stay in the bent part of the communication pipe. In the case of air with such a low pressure, even if an air breather was provided, it could not be discharged to the outside.

  Therefore, an object of the present invention is to remove the air in the oil flowing through the communication pipe so that it is not supplied to the transmission mechanism.

  In the present invention, the torque converter and the speed change mechanism are provided separately, and an oil pump driven by the engine is provided on the torque converter side to suck oil from the oil pan on the speed change mechanism side through the communication pipe. In the automatic transmission, the separation pipe for separating the air and the oil, the discharge pump for discharging the air in the separation chamber, and the control for controlling the discharge pump are provided in the communication pipe between the oil pump and the oil pan. And the control means is configured to operate the discharge pump while the power switch for starting the engine is on and the engine speed is equal to or lower than the threshold speed.

According to the present invention, the mass of air in the oil flowing through the communication pipe is separated from the oil in the separation chamber, and the oil containing the mass of air is not supplied to the speed change mechanism via the oil pump. The occurrence of a shock can be suitably prevented.
Also, since the air in the separation chamber is discharged by the discharge pump, the air separated from the oil and accumulated in the separation chamber is reliably discharged from the separation chamber even if it is air having a pressure lower than the atmospheric pressure. Never stay indoors.
Furthermore, since the engine speed is equal to or lower than the threshold speed, the flow rate of the oil sucked by the oil pump driven by the engine is slow, and the discharge pump operates only while the lump of air tends to stay in the communication pipe. A large amount of air will not accumulate in the communication pipe, and it can be handled with a very compact pump. Furthermore, the air can be removed while operating the discharge pump efficiently.

It is a schematic block diagram of the automatic transmission which employ | adopted the air separation structure concerning embodiment. It is a figure explaining the separation chamber provided in the communicating pipe. FIG. 6 is a correlation diagram between the engine speed and the amount of air contained in oil flowing in a pipe. It is a control flowchart of an electric pump.

Hereinafter, the case where the air separation structure in the automatic transmission according to the present invention is employed in the automatic transmission 1 provided separately by separating the torque converter and the transmission mechanism will be described as an example.
FIG. 1 is a schematic configuration diagram of an automatic transmission 1 that employs an air separation structure according to an embodiment. FIG. 2 is a diagram illustrating the separation chamber 30 provided in the communication pipe 14.

  The automatic transmission 1 according to the embodiment includes a front unit 10 provided at the front of the vehicle together with the engine 2 and a rear unit 20 provided at the rear of the vehicle together with a differential device (not shown). Power transmission to the unit 20 is performed via a propeller shaft (not shown) that connects the front unit 10 and the rear unit 20.

  The front unit 10 includes a torque converter 11 and an oil pump 12 that is driven by an engine, and these are housed in a converter casing 13.

The torque converter 11 includes a pump impeller to which rotation from the engine 2 is input, a turbine runner arranged to face the pump impeller, and a stator that controls the flow of oil circulating between the two.
In the torque converter 11, the rotation input to the pump impeller is transmitted to the turbine runner via a fluid or the like, and then the rotation is transmitted to the transmission mechanism 21 of the rear unit 20 connected to the turbine runner via a propeller shaft. It is designed to be entered.

The oil pump 12 is connected to the control valve body 23 of the rear unit 20 via the communication pipe 14, and the control valve body 23 is provided with an oil strainer (not shown).
The oil pump 12 sucks the oil in the oil pan 24 through the oil strainer, pressurizes the sucked oil, supplies the oil to the torque converter 11 as working oil, and supplies it to the control valve body 23.
The oil supplied to the control valve body 23 is supplied to a predetermined fastening element of the transmission mechanism 21 after the pressure is regulated by a control valve (not shown).

The rear unit 20 includes a transmission mechanism 21 and a differential device (not shown).
The transmission mechanism 21 changes the rotation input from the front unit 10 side, and the differential device transmits the changed rotation to drive wheels (not shown).

The transmission mechanism 21 includes a gear and a fastening element (not shown) and is accommodated in the transmission case 22.
A control valve body 23 is fixed to the lower surface of the transmission case 22, and an oil pan 24 is provided so as to cover the control valve body 23.

The lower part of the transmission case 22 is open, and oil used for lubricating and fastening the fastening elements of the transmission mechanism 21 moves into the oil pan 24 by its own weight.
An intake port of an oil strainer (not shown) attached below the control valve body 23 is located in the oil pan 24, and an exhaust port communicates with a communication pipe 14 connected to the control valve body 23. .

  The communication pipe 14 includes a communication pipe 14a that allows the separation chamber 30 and the control valve body 23 to communicate with each other, and a communication pipe 14b that allows the separation chamber 30 and the oil pump 12 to communicate with each other. The communication pipe 14a and the communication pipe 14b In between, a separation chamber 30 for separating a mass of air from oil flowing in the communication pipe 14 is provided.

  2A is a cross-sectional view of the separation chamber 30, FIG. 2B is a cross-sectional view along the line AA in FIG. 2A, and FIG. 2C is a cross-sectional view along the line BB in FIG. It is.

  The separation chamber 30 has a cylindrical shape whose upper and lower ends are sealed. The communication pipe 14a is connected to a position offset by a predetermined distance from the upper end 30a to the lower end 30b, and the communication pipe 14b is connected in the vicinity of the lower end 30b. Has been.

  As shown in FIG. 2B, the communication pipe 14 a and the communication pipe 14 b are on a straight line X parallel to the tangent T of the circle formed by the outer periphery of the separation chamber 30 when viewed from above (in the axial direction) the separation chamber 30. Are provided so as to extend in directions opposite to each other.

The communication pipe 14 a is provided so that a straight line X passing through the center thereof intersects a diameter line D passing through the center O of the separation chamber 30 at a predetermined angle α.
The oil supplied into the separation chamber 30 is swirled so that the oil supplied into the separation chamber 30 through the communication pipe 14a flows from the tangential direction to the space S in the cylindrical separation chamber 30. This is to form a flow.

  The communication pipe 14b is provided so as to extend from the side surface on the lower end 30b side of the connection position between the separation chamber 30 and the communication pipe 14a to the downstream side in the swirling direction of the swirling flow formed in the separation chamber 30. Yes. The oil that forms a swirling flow in the separation chamber 30 flows along the circumferential direction of the separation chamber 30 along the circumferential direction, and moves to the lower end 30b side by its own weight to form an oil vortex. This is for discharging from the communication pipe 14b.

The upper end 30a side of the separation chamber 30 relative to the connection position with the communication pipe 14a is a capture space 31 for capturing air separated from the oil.
A suction pipe 61 extending from the electric pump 60 (see FIG. 1) is connected to the upper end 30 a of the separation chamber 30, and the suction port 61 a of the suction pipe 61 is the center of the swirling flow formed by oil in the separation chamber 30. It is located directly above (center O of the separation chamber 30).

  As shown in FIG. 1, the electric pump 60 is connected to the separation chamber 30 via a suction pipe 61 and is connected to the transmission case 22 via an exhaust pipe 62.

In the embodiment, the operation / non-operation of the electric pump 60 is controlled by the control means 40. During operation, the electric pump 60 sucks and sucks the air in the separation chamber 30 via the suction pipe 61. Air is discharged into the transmission case 22 via the exhaust pipe 62.
At this time, the electric pump 60 is set so that the inside of the separation chamber 30 is in a negative pressure state slightly lower than the atmospheric pressure, and a relatively large mass of air contained in the oil under the negative pressure state. Not only fine bubbles are also easily separated from the oil.
This is because, by setting the negative pressure state, the volume of fine bubbles also expands and is easily separated from the oil flowing in the separation chamber 30.
Furthermore, even if the mass of air separated from the oil is a mass of air whose pressure is lower than the atmospheric pressure and cannot be discharged by a conventional air breather, it is discharged without staying in the separation chamber 30. I try to do it.

A signal from the engine speed sensor 41 and a signal from the power switch 42 are input to the control means 40.
The function of the control means 40 is realized by a CPU provided in an ATCU (automatic transmission control unit) (not shown).

  The engine speed sensor 41 is a sensor that detects the rotation of a crankshaft (not shown) of the engine 2 and outputs a signal indicating the engine speed to the control means 40.

The power switch 42 is a switch that can be switched between an ON position (power supply position) and an OFF position (power supply non-supply position) by operating the operation knob.
The power switch 42 is provided at a position that can be operated by a driver in the vehicle interior. When the power switch 42 is switched to the on position, the drive command for the engine 2 is output to an engine ECU (not shown) and the engine 2 is started. A signal indicating the operation position (ON position / OFF position) selected by the knob is input to the control means 40.

In the embodiment, the control unit 40 puts the electric pump 60 into an operating state when the power switch 42 is in the ON position and the engine speed Ne is equal to or less than the threshold speed Nth (Ne ≦ Nth).
Further, when the power switch 42 is in the on position and the engine speed Ne is larger than the threshold speed Nth (Ne> Nth), or when the power switch 42 is in the off position, the electric pump 60 is brought into a non-operating state. To do.

Here, the relationship between the engine speed Ne and the amount of air contained in the oil flowing through the communication pipe 14 will be described.
FIG. 3 is a correlation diagram between the engine speed Ne when the electric pump is not used and the amount of air contained in the oil flowing through the communication pipe 14 (the amount of accumulated air in the pipe line).

In the embodiment, since the oil pump 12 of the automatic transmission 1 is driven to rotate by the rotation input from the engine 2, the engine rotational speed Ne and the rotational speed of the oil pump 12 are proportional to each other. As the rotational speed Ne decreases, the rotational speed of the oil pump 12 also decreases.
Here, since the flow rate of the oil flowing through the communication pipe 14 is determined according to the rotation speed of the oil pump, the flow rate of the oil is also proportional to the engine rotation speed.

When the engine speed decreases and the oil pump 12 speed decreases, the flow rate of the oil flowing in the communication pipe 14 becomes slow, and air tends to accumulate in a bent portion or the like in the communication pipe 14.
The amount of air accumulated in the communication pipe 14 increases as the engine speed Ne decreases (as the oil flow rate decreases).

For example, as shown in FIG. 3, when the engine speed Ne increases from the rotational speed Ne1 during idling toward the rotational speed Ne3, the oil flowing through the communication pipe 14 as the rotational speed of the oil pump 12 increases. The flow rate becomes faster.
Then, the air staying in the bent portion in the communication pipe 14 is drawn into the oil flow and flows together with the oil, so that the amount of air contained in the oil is indicated by the symbol a in the figure. Furthermore, it increases as the engine speed Ne increases.

When the flow rate of the oil becomes sufficiently high so that the air cannot flow in the bent portion in the communication pipe 14 or the like, the air is sucked into the oil pump all at once, and as shown by a symbol b in the figure, The amount of air sharply decreases at the boundary of the number Ne2, and after the rotational speed Ne3, the amount of air becomes almost zero, as indicated by the symbol c in the figure.
When the engine speed Ne is low, almost all of the air accumulated in the bent portion in the communication pipe 14 is drawn into the oil flow and disappears, and the oil flow rate is high, and the bend in the communication pipe 14 is high. This is because air does not newly accumulate in the portion.

  In addition, when the engine speed Ne that has exceeded the threshold speed Nth decreases and becomes equal to or lower than the threshold speed Nth again, the flow rate of the oil flowing in the communication pipe 14 becomes slow, and a bent portion in the communication pipe 14 etc. Air gradually accumulates. The amount of air that accumulates increases as the engine speed Ne decreases, as indicated by the symbol d in the figure.

In the embodiment, the engine speed at which the accumulated amount of air in the communication pipe 14 (pipe) becomes substantially zero (the engine speed that realizes the oil flow velocity at which a lump of air cannot stay in a bent portion in the communication pipe 14, etc. The lowest number of rotations of the number) is obtained through experiments or the like, and the threshold number of rotations Nth is determined based on the obtained number of rotations.
Then, on the low rotational speed side from the threshold rotational speed Nth, the control means 40 activates the electric pump 60 under the condition that the power switch 42 is in the ON position, and on the high rotational side, the electric pump 60 is not operated. It is set to be in the operating state.
By operating the electric pump 60 only while the oil flowing in the communication pipe 14 contains a large amount of air, it is possible to sufficiently suppress the occurrence of shock due to the air mass. This is because the consumed energy can be suppressed and the life of the electric pump 60 can be extended as compared with the case where the electric pump 60 is continuously operated.

  Here, the threshold rotational speed Nth is the lowest rotational speed among the engine rotational speeds at which the accumulated amount of air in the pipeline becomes zero, and is offset to a higher rotational speed than the rotational speed obtained through experiments or the like. It is preferable that the value is set. This is to ensure that air can be removed without being affected by oil pump characteristic fluctuation due to lot differences.

Hereinafter, operation control of the electric pump 60 by the control means 40 will be described with reference to FIGS. 1 and 4.
FIG. 4 is a flowchart of the operation / non-operation control of the electric pump 60 performed by the control means 40.

  When the power switch 42 is operated to the on position and the engine is started (step 101), the control means 40 determines that the engine speed Ne indicated by the signal from the engine speed sensor 41 is the threshold speed Nth in step 102. Hereinafter, it is confirmed whether or not (Ne ≦ Nth).

  When the engine rotational speed Ne is equal to or lower than the threshold rotational speed Nth (Ne ≦ Nth) in step 102, the control means 40 puts the electric pump 60 into an operating state in step 103. This is because the oil flowing in the communication pipe 14 contains a large amount of air, so that the air in the oil is removed.

  On the other hand, if the engine speed Ne is not less than or equal to the threshold speed Nth (Ne ≦ Nth) in step 102, that is, greater than the threshold speed Nth (Ne> Nth), the control means 40 deactivates the electric pump 60. The state is set (step 106). This is to suppress energy consumption by the electric pump 60.

After the electric pump 60 is put into operation in step 103, in step 104, the control means 40 confirms whether or not the engine speed Ne has become smaller than the engine speed Ne1 during idling and the engine has stopped. .
If the engine speed Ne is high and the engine speed Ne1 during idling is also large, the process proceeds to step 102.

On the other hand, when the engine speed Ne is smaller than the idling speed Ne1 in step 104, in step 105, the control means 40 determines whether or not the power switch 42 is in the off position (whether or not it has been switched to the off position). )
If it is the off position, the process is terminated. If it is not the off position but the on position, the process proceeds to step 102.

  As a result, the processing from step 102 to step 106 is repeated until the power switch 42 is switched to the OFF position thereafter, and while the engine speed Ne is equal to or lower than the threshold speed Nth (Ne ≦ Nth). The electric pump 60 is in an operating state, and the electric pump 60 is in a non-operating state while the electric pump 60 is larger than the threshold rotational speed Nth (Ne> Nth).

Air separation in the separation chamber 30 when the electric pump 60 is in operation will be described with reference to FIG.
The oil that is supplied from the communication pipe 14a into the separation chamber 30 from the tangential direction and forms a swirling flow in the separation chamber 30 flows along the circumferential direction of the separation chamber 30 along the circumferential direction, and moves toward the lower end 30b by its own weight. It moves to form an oil vortex and is discharged from the communication pipe 14b on the lower end 30b side.
At this time, centrifugal force acts on the oil flowing in the separation chamber 30 and the oil is pressed against the inner peripheral surface side of the separation chamber 30, so that a decompressed space is formed on the center O side of the separation chamber 30. The
Here, the mass of the air contained in the oil is negligible compared to that of the oil, and therefore is collected on the center O side of the separation chamber 30 without being affected by the centrifugal force.
Therefore, the air contained in the oil is separated from the oil on the surface in contact with the decompressed space on the center O side of the separation chamber 30, and is captured in the capture space 31 in the upper part of the separation chamber 30.

Therefore, since the lump of air contained in the oil is separated from the oil, it is not supplied to the transmission mechanism together with the oil via the oil pump.
Furthermore, since the air separated from the oil and captured in the capture space 31 is sucked by the electric pump 60 and discharged into the transmission case 22, even if the flow velocity of the oil flowing through the communication pipe 14 increases. , Never pulled into the oil pump.

  At this time, since the oil forms a spiral swirl flow in the separation chamber 30 that has been brought into a negative pressure state by the electric pump 60, the oil is included in the oil when moving while spirally swirling in the separation chamber. The air as well as the air bubbles can be separated more from the oil.

  Here, the electric pump 60 in the embodiment corresponds to the discharge pump in the invention.

As described above, in the present embodiment, the torque converter 11 and the transmission mechanism 21 are provided separately, and the oil pump 12 that is driven by the engine is provided on the torque converter 11 side, and the oil pan on the transmission mechanism 21 side is provided. 24, in the automatic transmission 1 that sucks oil through the communication pipe 14 (14a, 14b), provided in the middle of the communication pipe 14 between the oil pump 12 and the oil pan 24, A separation chamber 30 to be separated, an electric pump 60 that discharges air in the separation chamber 30, and a control unit 40 that controls operation / non-operation of the electric pump 60 are provided, and the control unit 40 has power for starting the engine. The engine speed at which the switch 42 is in the ON position and the engine speed Ne realizes the oil flow velocity at which the mass of air cannot stay in the communication pipe 14. During a following threshold rotation speed Nth defining the (Ne ≦ Nth), and configured to operate the electric pump 60.
As a result, the air mass in the oil flowing through the communication pipe 14 is separated from the oil in the separation chamber 30, and the oil containing the air mass is not supplied to the transmission mechanism 21 via the oil pump 12. It is possible to suitably prevent the occurrence of shock due to the clumps.
Further, since the air trapped in the separation chamber 30 is discharged by the electric pump 60, even if the trapped air is air whose pressure is lower than the atmospheric pressure, the air is reliably discharged from the separation chamber 30, and the separation chamber 30 It does not stay within 30.
Furthermore, even if the length of the communication pipe 14 is increased and the number of bent portions in the communication pipe 14 is increased, air can be suitably removed, so that the degree of freedom in the layout of the hydraulic pipes in the automatic transmission is improved.
Further, while the engine speed Ne is equal to or less than the threshold engine speed Nth that defines the engine speed that achieves the oil flow rate at which the lump of air cannot stay in a bent portion or the like in the communication pipe 14, that is, the engine speed Ne. Therefore, the electric pump 60 is operated only while the flow rate of the oil sucked by the oil pump 12 is slow and the lump of air tends to stay in the communication pipe 14.
Therefore, by determining the operation of the electric pump based on the threshold rotation speed Nth, even if the amount of air increases, the air can be reliably removed and discharged to the transmission case side.
Furthermore, since the operation / non-operation of the electric pump 60 is appropriately switched, the energy consumed for the operation of the electric pump 60 is suppressed, and the life of the electric pump 60 is longer than when the electric pump 60 is operated continuously. Can be extended.
In particular, since the operation time of the electric pump 60 is shortened, the durability reliability of the components of the electric pump 60 is improved, and the durability performance requirements for the components are higher than when the electric pump 60 is continuously operated. Since it is mitigated, it is possible to reduce the manufacturing cost of parts by that amount, and the electric pump can be provided at a lower cost.
Further, when the electric pump 60 is operated, the degree of negative pressure in the separation chamber 30 that is in a negative pressure state by driving the oil pump 12 is further increased, so that the suction force of the oil pump 12 is assisted by the electric pump 60. Thus, efficient pump suction is possible.

Hereinafter, features in the embodiment are extracted and described.
The communication pipe 14 is a communication pipe 14 a that connects the separation chamber 30 and a control valve body 23 provided with an oil strainer that sucks oil in the oil pan 24, and a communication that connects the separation chamber 30 and the oil pump 12. The communication pipe 14a is connected to the separation chamber 30 at a position offset from the upper end 30a of the separation chamber 30 toward the lower end 30b, and the communication pipe 14b is closer to the lower end 30b than the communication pipe 14a. The separation chamber 30 was connected at a position, and in the separation chamber 30, the upper end 30 a side of the connection position of the communication pipe 14 a was used as an air capture space 31 separated from oil.
Most of the mass of air in the oil flowing through the communication pipe 14 a flows through the upper side of the communication pipe 14 a filled with oil, so that when oil is supplied into the separation chamber 30, Since the capture space 31 that is not filled with oil is secured, the air mass in the oil is separated from the oil and captured in the capture space 31. Therefore, the lump of air in the oil is not supplied to the transmission mechanism 21 together with the oil through the oil pump 12.
Further, since the electric pump 60 sucks the air in the separation chamber 30 (capturing space 31) and discharges it into the transmission case 22, even if air exceeding the volume of the capturing space 31 is separated from the oil, Air does not overflow from the capture space 31 and is supplied to the oil pump 12. Furthermore, since the oil flows in the separation chamber 30 from the upper side to the lower side, the air trapped in the trapping space 31 is not drawn into the oil pump 12.
Therefore, it is possible to suitably prevent the occurrence of shock due to the air mass.

The communication pipe 14a is formed on the side surface of the separation chamber 30 so that oil flows from the tangential direction into the cylindrical space S in the separation chamber 30 and the oil supplied into the separation chamber 30 forms a swirling flow. It was set as the structure connected from the tangential direction.
Thereby, the oil guided into the separation chamber 30 through the communication pipe 14a moves from the upper end 30a side to the lower end 30b side by its own weight while turning along the inner peripheral surface in the separation chamber 30. A spiral swirl flow is formed in the chamber 30 by the oil.
At this time, the oil flowing in the separation chamber 30 is pressed against the inner peripheral surface side of the separation chamber 30 by centrifugal force, so that a decompressed space is formed on the center O side of the separation chamber 30. Here, the air contained in the oil has a negligible mass compared to the oil, and is collected on the center O side of the separation chamber 30 without being affected by the centrifugal force, so that the oil is in contact with the decompressed space. Is captured in a capture space 31 at the top of the separation chamber 30.
Further, since a spiral swirl flow is formed in the separation chamber 30 by the oil, the residence time and the moving distance of the oil in the separation chamber 30 become longer, and the opportunity for the air to be separated from the oil accordingly. To increase.
Furthermore, a spiral swirl flow is formed in the separation chamber 30 regardless of the inclination of the vehicle on which the automatic transmission is mounted, so that air from the oil can be reliably supplied without being affected by the inclination of the vehicle. It becomes possible to separate.
In addition, since the electric pump 60 places the inside of the separation chamber 30 in a negative pressure state, even if it is a fine bubble contained in the oil, the volume expands and is easily separated from the oil.

In the embodiment, the case where the power switch is adopted is exemplified. However, when authentication is performed by wireless communication between the in-vehicle device and the portable device owned by the driver, and the encryption key matches, for example, only the button operation is performed. Therefore, the present invention can also be suitably applied to an automatic transmission of a vehicle in which the engine can be started / stopped by a vehicle, that is, a vehicle employing a so-called keyless entry system.
In this case, the button for starting and stopping the engine is turned on, and the electric pump 60 is put into an operating state while the engine speed Ne is equal to or less than the threshold speed Nth.
Further, the present invention can be suitably applied to an automatic transmission of a vehicle that employs an ignition switch instead of a power switch.

DESCRIPTION OF SYMBOLS 1 Automatic transmission 2 Engine 10 Front unit 11 Torque converter 12 Oil pump 13 Converter casing 14, 14a, 14b Communication pipe 20 Rear unit 21 Transmission mechanism 22 Transmission case 23 Control valve body 24 Oil pan 30 Separation chamber 30a Upper end 30b Lower end 31 Capture space 40 Control means 41 Engine speed sensor 42 Power switch 60 Electric pump (discharge pump)
61 Suction pipe 61a Suction port 62 Exhaust pipe S Space

Claims (1)

A torque converter and a speed change mechanism are provided separately, and an oil pump driven by an engine is provided on the torque converter side and automatically draws oil from an oil pan on the speed change mechanism side through a communication pipe. In the transmission,
A separation chamber provided in a communication pipe between the oil pump and the oil pan to separate air and oil;
A discharge pump for discharging air in the separation chamber;
Control means for controlling the discharge pump,
The air separation structure in an automatic transmission, wherein the control means operates the discharge pump while the switch for starting the engine is on and the engine speed is equal to or less than a threshold speed.

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