JP2014173705A - Automatic transmission and control method of the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To achieve, in an automatic transmission equipped on a vehicle which performs idle stop control of an engine, satisfactory starting property when restarting the engine, and prevent erroneous starting of the vehicle caused by system-restarting of the engine in a state that the automatic transmission is in a non-running range while suppressing capacity enlargement of an electric pump.SOLUTION: An automatic transmission comprises: an LR brake 60 and a low clutch 40 which are engaged when starting; an electric pump 101 producing hydraulic pressure during automatic stop of an engine; a first oil passage 111, 115 leading from the electric pump 101 to the LR brake 60 via a first LSV 105, in which the pressure can be discharged only through a drain port of the first LSV 105; and a second oil passage 112, 116 leading from the electric pump 101 to the low clutch 40. The second oil passage is provided with a second LSV 106 which supplies hydraulic pressure of the magnitude, by which the low clutch 40 is not in an engaged state, to the clutch 40 during automatic stop of the engine in the non-running range.

Description

  The present invention relates to an automatic transmission for a vehicle in which idle stop control for automatically stopping an engine when the vehicle is stopped, and a control method thereof, and relates to the technical field of the automatic transmission for a vehicle.

  Conventionally, in an automatic transmission, it is customary to achieve the starting gear stage by engaging one frictional engagement element and a one-way clutch. However, the one-way clutch is heavy and has a friction resistance other than the starting gear stage. For this reason, it has been studied to abolish this from the viewpoint of improving the fuel efficiency of the engine, etc., and to achieve the starting shift stage by fastening two friction engagement elements.

  On the other hand, a vehicle that performs idle stop control that automatically stops the engine when a predetermined stop condition is satisfied when the vehicle stops at an intersection has been put into practical use. In an automatic transmission mounted on such a vehicle, the next start In order to achieve a quick start sometimes, an electric oil pump (hereinafter referred to as “electric pump”) is provided separately from a mechanical oil pump (hereinafter referred to as “mechanical pump”) driven by the engine. By supplying the hydraulic pressure generated by the pump, a starting frictional engagement element that transmits power when starting the engine is fastened even when the engine is stopped.

  However, when the driver switches the automatic transmission from a travel range such as the D range to a non-travel range such as the N range before and after the automatic stop of the engine when the vehicle is stopped, each friction engagement element in the automatic transmission Therefore, even if the electric pump is operated during the automatic stop of the engine, the starting frictional engagement element is not engaged. Accordingly, when the vehicle is switched to the travel range at the time of starting, the starting frictional engagement element is re-engaged. However, at that time, the startability after engine restart may be deteriorated due to the engagement delay of the frictional engagement element. .

  In order to solve this problem, Patent Document 1 discloses that in an automatic transmission having an electric pump that operates during an automatic engine stop, the automatic transmission is switched to a non-traveling range before and after the engine is automatically stopped. Also, it is disclosed that the hydraulic pressure generated by the electric pump is supplied to the starting frictional engagement element, and the starting frictional engagement element is fastened in the same manner as in the traveling range. According to this, when the automatic transmission is switched to the travel range at the time of starting, it is possible to start immediately after restarting the engine, and good startability can be obtained.

JP 2012-30779 A

  By the way, in idling stop control that automatically stops the engine while the vehicle is stopped, the engine is automatically restarted when, for example, the remaining battery capacity falls below a predetermined value or when a device with high power consumption such as an air conditioner is activated. In this case, in the automatic transmission, if the control for fastening the starting frictional engagement element in the non-traveling range is performed, the engine will be restarted. On the other hand, the vehicle starts wrongly.

  Therefore, when the automatic transmission is in the non-traveling range and the starting frictional engagement element is engaged, when the engine is restarted, the electric pump is stopped and hydraulic pressure is applied from the pump to the starting frictional engagement element. The hydraulic control valve such as a solenoid valve installed in the oil passage to be supplied is controlled to discharge the hydraulic pressure supplied to the starting frictional engagement element and release the frictional engagement element. When an open failure occurs (failure that does not work when the oil passage is in communication), the hydraulic pressure is not quickly discharged from the electric pump, so there is a situation where the engine restarts in a state where the starting frictional engagement element is not released, As described above, the vehicle erroneously starts in the non-traveling range.

  In order to solve this problem, in the invention disclosed in Patent Document 1, a part of the hydraulic oil from the oil passage is disposed upstream of the solenoid valve of the oil passage from the electric pump to the starting frictional engagement element via the solenoid valve. Even if the solenoid valve opens, if the electric pump is stopped, the hydraulic pressure supplied to the starting frictional engagement element is discharged by the exhaust pressure circuit. According to this, when the solenoid valve opens, the erroneous start of the vehicle in the non-traveling range due to the engine restarting in a state where the starting frictional engagement element is not released is prevented.

  However, when the exhaust pressure circuit as described above is provided in the oil passage from the electric pump to the starting frictional engagement element, a part of the hydraulic oil discharged from the pump is discharged from the exhaust pressure circuit during the operation of the electric pump. As a result, the electric pump capacity must be increased in order to secure the amount of hydraulic oil or hydraulic pressure necessary for fastening the starting frictional engagement element while the engine is stopped. It will be necessary.

  In particular, as described above, in the case of an automatic transmission that eliminates the one-way clutch and achieves the start gear stage by engaging two friction engagement elements, these start friction engagement elements are engaged while the engine is stopped. Therefore, the electric pump is further increased in size, leading to an increase in the weight of the vehicle or an increase in power consumption for driving the electric pump.

  Accordingly, the present invention provides an automatic transmission mounted on a vehicle that performs engine idle stop control, and a frictional engagement element for starting by hydraulic pressure generated by an electric pump in a travel range and a non-travel range during automatic engine stop. When the control for fastening is performed, ensuring good startability when switched from the non-traveling range to the traveling range, and without causing an increase in the capacity of the electric pump, an increase in power consumption, etc. It is an object of the present invention to prevent erroneous start in the non-traveling range of the vehicle when a hydraulic control valve such as a solenoid valve fails to open.

In order to solve the above problems, first, the invention according to claim 1 of the present application is
An automatic mounted on a vehicle that performs engine idle stop control that automatically stops the engine when a predetermined stop condition is satisfied and automatically restarts the engine when a predetermined restart condition is satisfied in an automatic stop state. A transmission,
A first friction engagement element and a second friction engagement element that are engaged when starting,
A hydraulic pressure generating device for generating hydraulic pressure during the automatic stop of the engine;
A hydraulic control valve having an input port, an output port and a drain port;
The hydraulic pressure is supplied from the hydraulic pressure generating device to the first frictional engagement element via the input port and the output port of the hydraulic control valve, and the hydraulic pressure supplied to the first frictional engagement element is supplied only to the drain port of the hydraulic control valve. A first oil passage that can be discharged from
A second oil passage leading from the oil pressure generating device to the second frictional engagement element;
Control that is provided in the second oil passage and that supplies the second frictional engagement element with a hydraulic pressure that does not cause the second frictional engagement element to be engaged during automatic stop of the engine in which the automatic transmission is in the non-traveling range. And a device.

According to a second aspect of the present invention, in the automatic transmission according to the first aspect,
The second oil passage is provided with a hydraulic pressure detection device that detects whether or not the hydraulic pressure supplied to the second frictional engagement element is large enough to prevent the second frictional engagement element from being engaged. To do.

According to a third aspect of the present invention, in the automatic transmission according to the first or second aspect,
The control device controls a hydraulic pressure supplied to the second frictional engagement element so that the second frictional engagement element is in an unengaged state after the second frictional engagement element is in an engaged state.

Furthermore, the invention according to claim 4 is the automatic transmission according to any one of claims 1 to 3,
The hydraulic pressure supplied to the second frictional engagement element is a hydraulic pressure at which the second frictional engagement element is brought into a slip state by a torque when the vehicle starts.

On the other hand, the invention described in claim 5
An automatic mounted on a vehicle that performs engine idle stop control that automatically stops the engine when a predetermined stop condition is satisfied and automatically restarts the engine when a predetermined restart condition is satisfied in an automatic stop state. A transmission control method comprising:
A first friction engagement element and a second friction engagement element that are engaged when starting,
A hydraulic pressure generating device for generating hydraulic pressure during the automatic stop of the engine;
A hydraulic control valve having an input port, an output port and a drain port;
The hydraulic pressure is supplied from the hydraulic pressure generating device to the front first frictional engagement element via the input port and the output port of the hydraulic control valve, and the hydraulic pressure supplied to the first frictional engagement element is supplied only to the drain port of the hydraulic control valve. A first oil passage that can be discharged from
An automatic transmission having a second oil passage leading from the hydraulic pressure generating device to the second frictional engagement element;
During the automatic stop of the engine in which the automatic transmission is in a non-traveling range, the second frictional engagement element is supplied with a hydraulic pressure of a magnitude that does not allow the second frictional engagement element to be engaged.

  According to the first aspect of the present invention, when the engine is automatically stopped in a state where the automatic transmission is in the non-traveling range, the hydraulic pressure generated by the hydraulic pressure generating device is controlled by the first hydraulic passage. If the first frictional engagement element is supplied via the first frictional engagement element, the first frictional engagement element is fastened, and the second frictional engagement element is supplied with the hydraulic pressure generated by the hydraulic pressure generating device through the second oil passage. However, at this time, the hydraulic pressure supplied to the second frictional engagement element is such that the second frictional engagement element is not in the engaged state, and the second frictional engagement element is supplied with hydraulic pressure. However, it is not fastened, so it will be ready for fastening.

  Therefore, when the switching operation from the non-traveling range to the traveling range is performed, the second frictional engagement element is fastened compared to the case where the hydraulic pressure is supplied from the completely released state, When the engine is restarted, the vehicle can start immediately.

  On the other hand, when the automatic transmission is in the non-running range and the engine restarts due to a decrease in the remaining capacity of the battery or the like, the output port of the hydraulic control valve and the drain port are connected to each other. The hydraulic pressure supplied to the frictional engagement element is discharged to release the first frictional engagement element. At this time, however, the hydraulic control valve temporarily fails to open and the first frictional engagement element cannot be released. Even if the state occurs, the second frictional engagement element is in the engagement preparation state as described above, and is not in the engagement state that enables power transmission, so that the engine is not released in the state where the first friction engagement element is not released. If the vehicle restarts, the vehicle will not start erroneously.

  In such a case, as in the past, in preparation for an open failure of the hydraulic control valve, a part of the hydraulic oil is always supplied to the oil passage from the hydraulic pressure generating device such as an electric pump that operates during the automatic engine stop to the friction engagement element. Since it is not necessary to provide a discharge pressure circuit for discharging, an increase in capacity of the electric pump or the like, an increase in power consumption, and the like are suppressed.

  According to the second aspect of the present invention, the hydraulic pressure detection device provided in the second oil passage is such that the hydraulic pressure supplied to the second frictional engagement element does not cause the second frictional engagement element to be in the engaged state. Since it is detected whether or not it is large, the control for making the second friction engagement element ready for engagement is executed accurately while the engine is stopped in the non-traveling range, and the erroneous start of the vehicle as described above is reliably prevented. Will be.

  According to the third aspect of the present invention, the hydraulic pressure supplied to the second frictional engagement element while the engine is stopped in the non-traveling range is increased by the hydraulic control device to the hydraulic pressure that is once engaged. Since the hydraulic pressure is lowered to the non-engaged state, the second friction engagement element can be accurately controlled to the non-engaged state close to the engaged state. As a result, the second frictional engagement element is quickly fastened when the automatic transmission is switched to the traveling range and reliably starts, while preventing erroneous start of the vehicle in the non-driving range, thereby achieving better starting. Sex will be obtained.

  According to a fourth aspect of the present invention, the hydraulic pressure supplied to the second frictional engagement element is a hydraulic pressure at which the second frictional engagement element slips due to torque at the start of the vehicle. As in the third aspect of the invention, it is possible to obtain a good startability when the automatic transmission starts when the automatic transmission is switched to the travel range while reliably preventing erroneous start of the vehicle in the non-travel range.

  And according to invention of the method of Claim 5, the effect similar to the invention of the said Claim 1 is achieved.

1 is a skeleton diagram of a main part of an automatic transmission according to an embodiment of the present invention. It is a table | surface which shows the relationship between the combination of fastening of a friction fastening element, and a gear stage. It is a circuit diagram which shows the structure of the principal part of a hydraulic circuit. It is a figure which shows the ON-OFF characteristic of a hydraulic switch. It is a block diagram which shows the control system of an engine and an automatic transmission. It is a flowchart which shows the example of an action | operation of an engine and an automatic transmission at the time of the engine automatic stop in N range. It is a time chart which shows the same operation example.

  Embodiments of the present invention will be described below.

  FIG. 1 is a skeleton diagram showing the configuration of an automatic transmission according to an embodiment of the present invention. The automatic transmission 1 has an input shaft to which engine output is input via a torque converter (not shown). 1 and 2, on the input shaft 2, from the engine side (the right side of the figure), first, second and third planetary gear sets (hereinafter simply referred to as “first, second and third gear sets”) 10, 20 and 30 are arranged, and the power from the input shaft 2 is transmitted to the gear set 10, 20, 30 side as a hydraulic friction engagement element for switching the power transmission path constituted by these gear sets 10-30. Low clutch 40 and high clutch 50 that selectively transmit, and low reverse brake (hereinafter referred to as “LR brake”) 60 that fixes predetermined rotational elements of each gear set 10, 20, 30, 2 speed 6 speed blur Key (hereinafter, "26 Brake" hereinafter) 70 and, the reverse speed third speed 5-speed brake (hereinafter, referred to as "R35 Brake") 80 and is provided.

  The gear sets 10, 20, 30 are all sun gears 11, 21, 31, a plurality of pinions 12, 22, 32 respectively engaged with these sun gears 11, 21, 31, and these pinions 12, 22, 32, and carriers 13, 23, 33 that respectively support 32, and ring gears 14, 24, 34 meshed with the pinions 12, 22, 32, respectively.

  The sun gear 11 of the first gear set 10 and the sun gear 21 of the second gear set 20 are coupled and connected to the output member 41 of the low clutch 40, and the carrier 23 of the second gear set 20 is connected to the high clutch 50. The input shaft 2 is directly connected to the sun gear 31 of the third gear set 30.

  In addition, the ring gear 14 of the first gear set 10 and the carrier 23 of the second gear set 20 are coupled to each other, and the LR brake 60 is disposed between the ring gear 14 and the transmission case 3. The ring gear 24 and the carrier 33 of the third gear set 30 are coupled to each other, and the 26 brake 70 is disposed between the ring gear 24 and the transmission case 3. Further, the ring gear 34 of the third gear set 30 and the transmission case are arranged. 3 and the R35 brake 80 is disposed. The output gear 4 that outputs the output of the automatic transmission 1 to the drive wheel (not shown) side is connected to the carrier 13 of the first gear set 10.

  With the above configuration, the automatic transmission 1 can move forward in the D range or the like as shown in FIG. The 1st to 6th speeds in the travel range and the reverse speed in the reverse range are achieved. As is clear from FIG. 2, in this embodiment, the low clutch 40 and the LR brake 60 constitute a frictional engagement element that is engaged at the start in the claims.

  Further, the automatic transmission 1 has a hydraulic circuit for selectively supplying hydraulic pressure to the friction engagement elements 40 to 80 to realize the shift stages. Next, referring to FIG. A configuration relating to hydraulic control during idle stop of the engine in the circuit 100, specifically, a configuration for controlling supply of hydraulic pressure to the low clutch 40 and the LR brake 60 that are engaged at the start will be described.

  As shown in FIG. 3, the hydraulic circuit 100 is driven by a motor from an electric pump (“hydraulic pressure generating device”) 101 that is driven by a motor 101 a to generate hydraulic pressure while the engine is stopped. Thus, the hydraulic pressure generated by the mechanical pump 102 that generates the hydraulic pressure is supplied.

  The hydraulic pressure generated from either the electric pump 101 or the mechanical pump 102 is used as a valve for supplying the hydraulic pressure supplied from the pumps 101 and 102 to the low clutch 40 and the LR brake 60. A pump switching valve 103 that switches whether to supply to the low clutch 40 and the LR brake 60, a manual valve 104 that is linked to the driver's range operation, and a first linear solenoid valve that controls the hydraulic pressure supplied to the LR brake 60 ( A “hydraulic pressure control valve” (hereinafter referred to as “first LSV”) 105 and a second linear solenoid valve (hereinafter referred to as “second LSV”) 106 that controls the hydraulic pressure supplied to the low clutch 40.

  The pump switching valve 103 is provided with first and second switching ports a and b for switching the position of the spool 103a at both the left and right ends. When the hydraulic pressure is introduced to the switching port a, the spool 103a is positioned at the first position (the illustrated position) on the right side, and when the mechanical pump 102 is operated, the hydraulic pressure is transferred from the pump 102 to the second switching port b on the right side in the drawing. Is introduced so that the spool 103a is positioned at the second position on the left side.

  The pump switching valve 103 has LR brake first and second input ports c and d and an output port e, and low clutch first and second input ports f and g and an output port h. When the spool 103a is in the first position, as shown in the figure, the LR brake first input port c communicates with the output port e, and the low clutch first input port f communicates with the output port h. When the spool 103a is in the second position, although not shown, the LR brake second input port d communicates with the output port e and the low clutch second input port g communicates with the output port h. It has become.

  The first input port c for the LR brake and the first input port f for the low clutch are connected to the first input line led from the electric pump 101 (upstream portion of the “first oil passage” in the claims). 111 and a second input line (upstream part of “second oil passage” in claims) 112 are connected to each other, and the second input port d for LR brake is directly led from the mechanical pump 102. The fourth input line 114 led from the mechanical pump 102 via the manual valve 104 is connected to the third input line 113 and the second input port g for low clutch.

  Further, the LR brake output port e of the pump switching valve 103 is led to the LR brake 60 via the first LSV 105 by an LR brake line (downstream part of “first oil passage” in claims). The low clutch output port h is led to the low clutch 40 via the second LSV 106 by a low clutch line (downstream portion of “second oil passage” in claims).

  Further, on the downstream side of the second SLV 106 in the low clutch line 116, a hydraulic switch (a “hydraulic pressure detecting device” in the claims) 117 for detecting the hydraulic pressure supplied to the low clutch 40 through the line 116 is installed. Yes.

  As shown in FIG. 4, the hydraulic switch 117 switches from OFF to ON when the hydraulic pressure supplied to the low clutch 40 exceeds a first predetermined pressure, and a second predetermined pressure lower than the first predetermined pressure. When the pressure becomes lower than the pressure, it is switched from ON to OFF, and so-called ON / OFF hysteresis is provided. In this case, the first predetermined pressure is a hydraulic pressure when the low clutch 40 is engaged, and the second predetermined pressure is a hydraulic pressure when the clutch 40 is non-engaged and slips. Is set.

  The manual valve 104 communicates the mechanical pump 102 with the fourth input line 114 on the downstream side when operated in the D range, and drains the line 114 when operated in the N range. It has become.

  Each of the first and second LSVs 105 and 106 has an upstream input port i, a downstream output port j, and a drain port k. When the input port i and the output port j are opened, When closed, the ports i and j are disconnected, and the downstream output port j is connected to the drain port k.

  With the above configuration, the automatic transmission 1 according to this embodiment is configured to control the engagement state of the low clutch 40 and the LR brake 60 in conjunction with engine idle stop control. A device 200 is provided.

  As shown in FIG. 5, the control device 200 includes a signal from a range sensor 201 that detects the range of the automatic transmission 1 selected by the driver's operation, and a vehicle speed sensor 202 that detects the vehicle speed of the vehicle. A signal, a signal from an accelerator operation amount sensor 203 for detecting an operation amount of an accelerator pedal of a driver, a signal from a brake switch 204 for detecting depression of a brake pedal, and an engine speed sensor 205 for detecting an engine speed. A signal, a signal from the electric pump rotation speed sensor 206 for detecting the rotation speed of the electric pump 101, a signal from the battery remaining capacity sensor 207 for detecting the remaining battery capacity, an ON-OFF signal from the hydraulic switch 117, and the like. It is designed to be entered.

  Based on these signals, the control device 200 outputs signals for automatic stop or automatic restart to the engine fuel supply device 211, the ignition device 212, and the start device 213 in order to perform engine idle stop control. In addition, a control signal is output to the first and second LSVs 105 and 106 in the hydraulic circuit 100 for the engagement control of the LR brake 60 and the low clutch 40 of the automatic transmission, and further to the motor 101a of the electric pump 101. A signal instructing the operation is output.

  Next, an operation example of the present embodiment including the control operation by the control device 200 will be described with reference to the flowchart in FIG.

  The flowchart of FIG. 6 shows the operation when the vehicle stops from the running state. First, in step S1, various signals are input from the sensor switches 201 to 208 shown in FIG. It is determined whether or not the current range of the transmission 1 is the N range.

  When the vehicle is stopped, the range of the automatic transmission 1 is the D range. In the state before the engine is automatically stopped, the spool 103a of the pump switching valve 103 is in the second position in the hydraulic circuit 100 of FIG. The hydraulic pressure generated by the mechanical pump 102 driven on the engine (on the left side) is supplied from the third input line 113 to the LR brake 60 via the pump switching valve 103, the LR brake line 115, and the first LSV 105. The LR brake 60 is in the engaged state (reference numeral a in FIG. 7).

  The hydraulic pressure generated by the mechanical pump 102 is supplied to the low clutch 40 through the manual valve 104, the fourth input line 114, the pump switching valve 103, the low clutch line 116, and the second LSV 106. It is in a fastened state (reference a).

  In this state, when the automatic transmission 1 is switched to the N range, the process proceeds from step S2 to step S3 in FIG. 6, the spool of the manual valve 104 moves to the N position, and the fourth input line 114 is drained. Thus, the hydraulic pressure is discharged from the low clutch 40 and the low clutch 40 is released (reference number C). At this time, the hydraulic pressure generated by the mechanical pump 102 is continuously supplied to the LR brake 60 and maintained in the engaged state.

  Further, in step S4, it is determined whether or not the engine automatic stop condition is satisfied from the vehicle speed, the brake, the accelerator state, and the like. When the predetermined automatic stop condition is satisfied, the controller 200 supplies the engine fuel supply. A signal for stopping the engine is output to the device 211, the ignition device 212, and the like, and in step S5, the engine is automatically stopped to enter an idle stop state.

  At this time, the mechanical pump 102 is stopped, and an operation signal is output to the motor 101a of the electric pump 101 in step S6, and the electric pump 101 starts operating. Then, by switching the operating pump, the spool 103a of the pump switching valve 103 is moved to the first position (right side) in step S7, and the state of step S8, that is, the hydraulic pressure generated by the electric pump 101 is The hydraulic pressure that is supplied to the LR brake 60 through the first input line 111, the pump switching valve 103, the LR brake line 115, and the first LSV 105, and once lowered when the mechanical pump 102 stops, rises again, and the LR brake 60 It is fastened again (symbol D).

  Further, when the spool 103a of the pump switching valve 103 is moved to the first position (right side), the hydraulic pressure generated by the electric pump 101 is changed to the second input line 112, the pump switching valve 103, the low clutch line 116 and the first clutch. Although it is also supplied to the low clutch 40 via the 2LSV 106, at this time, in steps S9 to S11, the hydraulic pressure of the low clutch 40 is controlled by the second LSV 106 as follows.

  First, whether or not the signal from the hydraulic switch 117 installed in the low clutch line 116 has been switched from OFFk to ON, that is, the hydraulic pressure engaged with the low clutch 40 is changed to the engagement state of the clutch 40. It is determined whether or not the pressure has increased to a predetermined pressure. If the pressure has increased to the first predetermined pressure, then control is performed to decrease the hydraulic pressure (reference number O).

  Then, it is determined whether or not the hydraulic pressure has decreased to a second predetermined pressure lower than the first predetermined pressure. When the hydraulic pressure has decreased to the second predetermined pressure, the hydraulic pressure reduction control is terminated and supplied to the low clutch 40. The hydraulic pressure is held at the second predetermined pressure (reference sign F). Since the second predetermined pressure is the hydraulic pressure when the low clutch 40 is in the non-engaged state and slips, the clutch 40 is held in the slip state, in other words, in the ready state for engagement. .

  Next, in step S9, it is determined whether or not the automatic transmission 1 has been switched from the N range to the D range. If the automatic transmission 1 is switched to the D range, the engine is automatically restarted in accordance with steps S13 to S15, and the pump The spool 103a of the switching valve 103 is again moved to the second position, and the hydraulic pressure generated by the mechanical pump 102 that has started operation is supplied to the low clutch 40 and the LR brake 60. At this time, in step S16, the electric pump 101 stops.

  As a result, the low clutch 40 and the LR brake 60 are both engaged by the hydraulic pressure generated by the mechanical pump 102, and the vehicle is ready to start at the first speed. However, as described above, the LR brake 60 is previously engaged. In addition, since the low clutch 40 is ready for engagement and is immediately engaged by raising the hydraulic pressure, good startability can be obtained when the low clutch 40 is switched to the D range.

  On the other hand, before the automatic transmission 1 is switched to the D range, it is determined in step S17 whether or not the remaining capacity of the battery has dropped below a predetermined value. When the system restart is executed, in step S18, the first LSV 105 discharges the hydraulic pressure supplied to the LR brake 60 via the LR reverse line 115 (reference sign), and then in step S19. The engine restarts automatically. Therefore, the engine is restarted in a state where the LR brake 60 is released, and the vehicle does not start erroneously while the automatic transmission 1 is in the N range.

  Thereafter, in steps S20 and S21, as the engine is restarted, the spool 103a of the pump switching valve 103 is moved again to the second position, and the pump supplying hydraulic pressure to the low clutch 40 is switched from the electric pump 101 to the mechanical pump 102. However, the hydraulic pressure supplied to the low clutch 40 is maintained at the second predetermined pressure by the second LSV 106 thereafter. In step S16, the electric pump 101 is stopped.

  When the hydraulic pressure supplied to the LR brake 60 by the first LSV 105 is discharged in step S18, the first LSV 105 becomes inoperable with the input port i and the output port j communicating with each other due to an open failure. The hydraulic pressure supplied to the LR brake 60 cannot be discharged from the drain port k of the first LSV 105, and the LR brake 60 cannot be released (reference sign).

  Therefore, if the low clutch 40 is engaged, the vehicle erroneously starts in the N range when the engine is restarted in step S19. As described above, the low clutch 40 is in the ready state for engagement. That is, since the torque is not transmitted, even if the LR brake 60 is not released due to the opening failure of the first LSV 105, the power transmission path of the automatic transmission 1 is not in the first speed state, and the engine Even if the vehicle is started, the vehicle will not start erroneously.

  In this case, since the erroneous start is prevented by setting the low clutch 40 in the ready state for engagement, there is no need to provide an exhaust pressure circuit for preventing the erroneous start in the hydraulic circuit as in the prior art. Problems such as an increase in the capacity of the electric pump and an increase in power consumption due to the provision of the electric pump are avoided.

  In the above embodiment, the low clutch 40 is configured to be controlled to be in a ready state for engagement when the first LSV 105 that controls the hydraulic pressure of the LR brake 60 fails during automatic engine stop in the N range. However, the LR brake 60 may be controlled to be ready for engagement in the case where the second LSV 106 that controls the hydraulic pressure of the low clutch 40 has an open failure. In relation to the claims, in the former case, the LR brake 60 corresponds to the “first frictional engagement element” and the low clutch 40 corresponds to the “second frictional engagement element”. The LR brake 60 corresponds to the “first friction engagement element” and the “second friction engagement element”.

  As described above, according to the present invention, in an automatic transmission mounted on a vehicle that performs idle stop control of an engine, it is possible to ensure good startability when switched from a non-traveling range to a traveling range, and Without causing an increase in the capacity of the electric pump or an increase in power consumption, it is possible to prevent the automatic transmission from erroneously starting in the non-traveling range when the engine is restarted. Therefore, this type of automatic transmission or a vehicle equipped with the automatic transmission may be suitably used in the manufacturing industry.

1 Automatic transmission 40, 60 First and second friction engagement elements (low clutch, LR brake)
101 Hydraulic pressure generator (electric pump)
105 Hydraulic control valve (1st LSV)
111, 115 First oil passage (first input line, LR brake line)
112, 116 Second oil passage (second input line, low clutch line)
117 Oil pressure detection device (hydraulic switch)
200 Controller

Claims (5)

An automatic mounted on a vehicle that performs engine idle stop control that automatically stops the engine when a predetermined stop condition is satisfied and automatically restarts the engine when a predetermined restart condition is satisfied in an automatic stop state. A transmission,
A first friction engagement element and a second friction engagement element that are engaged when starting,
A hydraulic pressure generating device for generating hydraulic pressure during the automatic stop of the engine;
A hydraulic control valve having an input port, an output port and a drain port;
The hydraulic pressure is supplied from the hydraulic pressure generating device to the first frictional engagement element via the input port and the output port of the hydraulic control valve, and the hydraulic pressure supplied to the first frictional engagement element is supplied only to the drain port of the hydraulic control valve. A first oil passage that can be discharged from
A second oil passage leading from the oil pressure generating device to the second frictional engagement element;
Control that is provided in the second oil passage and that supplies the second frictional engagement element with a hydraulic pressure that does not cause the second frictional engagement element to be engaged during automatic stop of the engine in which the automatic transmission is in the non-traveling range. And an automatic transmission. The automatic transmission according to claim 1, wherein
The second oil passage is provided with a hydraulic pressure detection device that detects whether or not the hydraulic pressure supplied to the second frictional engagement element is large enough to prevent the second frictional engagement element from being engaged. Automatic transmission to do. The automatic transmission according to claim 1 or 2,
The automatic transmission controls the hydraulic pressure supplied to the second frictional engagement element so that the second frictional engagement element is in a non-engaged state after the second frictional engagement element is in an engaged state. The automatic transmission according to any one of claims 1 to 3,
2. The automatic transmission according to claim 1, wherein the hydraulic pressure supplied to the second frictional engagement element is a hydraulic pressure at which the second frictional engagement element is brought into a slip state by a torque when the vehicle starts. An automatic mounted on a vehicle that performs engine idle stop control that automatically stops the engine when a predetermined stop condition is satisfied and automatically restarts the engine when a predetermined restart condition is satisfied in an automatic stop state. A transmission control method comprising:
A first friction engagement element and a second friction engagement element that are engaged when starting,
A hydraulic pressure generating device for generating hydraulic pressure during the automatic stop of the engine;
A hydraulic control valve having an input port, an output port and a drain port;
The hydraulic pressure is supplied from the hydraulic pressure generating device to the front first frictional engagement element via the input port and the output port of the hydraulic control valve, and the hydraulic pressure supplied to the first frictional engagement element is supplied only to the drain port of the hydraulic control valve. A first oil passage that can be discharged from
An automatic transmission having a second oil passage leading from the hydraulic pressure generating device to the second frictional engagement element;
An automatic transmission that supplies hydraulic pressure of a magnitude that does not allow the second frictional engagement element to be in an engaged state during an automatic stop of an engine in which the automatic transmission is in a non-traveling range. Control method.

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