JP2016011735A - Control device of automatic transmission - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a control device of an automatic transmission capable of achieving a start stage with high response in restarting an engine, and suppressing fastening shock.SOLUTION: A low clutch and a low reverse brake are fastened in a start stage. During automatic stop of an engine by idle stop control, a fastening oil pressure is supplied to the low clutch, a first oil pressure is supplied to a clearance adjustment piston of the low reverse brake, and a third oil pressure lower than the second oil pressure but not generating a negative pressure in a hydraulic chamber of a pressing piston, is supplied to the pressing piston of the low reverse brake. When the first oil pressure is supplied to the clearance adjustment piston, the clearance adjustment piston strokes, thus the pressing piston is brought into contract with a friction plate, and a clearance of the friction plate becomes zero. When the second oil pressure is supplied to the pressing piston, the pressing piston presses the friction plate, thus the low reverse brake is brought in a fastened state.

Description

  The present invention relates to a control device for an automatic transmission, more specifically, a control device for an automatic transmission mounted on a vehicle on which idle stop control is performed, and a friction element including a clearance adjustment piston and a pressing piston. The present invention relates to a control device for an automatic transmission.

  Conventionally, in an automatic transmission mounted on a vehicle such as an automobile, the starting speed such as the first forward speed is achieved by fastening one friction element and engaging one one-way clutch. However, since the one-way clutch is heavy and drag resistance occurs at a speed other than the starting speed, as disclosed in Patent Document 1, the one-way clutch is eliminated and the starting speed is achieved by fastening two friction elements. It is known. Patent Document 1 includes a clearance adjusting piston (B piston) and a pressing piston (A piston) as one of the two friction elements that are fastened at the starting stage, in order to improve controllability. The use of a double acting friction element is disclosed.

  In the double-acting friction element, the B piston is provided in the transmission case so as to be able to make a stroke, and the A piston is provided so as to be relatively movable with respect to the B piston. When hydraulic pressure is supplied to the hydraulic chamber (B chamber) of the B piston and the B piston is stroked, the A piston comes into contact with the friction plate and the clearance of the friction plate becomes zero (the hydraulic pressure in the B chamber at this time is the first hydraulic pressure) To do). When hydraulic pressure is supplied from this state to the hydraulic chamber (A chamber) of the A piston, the A piston presses the friction plate and the double-acting friction element is brought into a fastening state (the hydraulic pressure in the A chamber at this time is changed to the second hydraulic pressure). To do). When the hydraulic pressure in the A chamber (that is, the second hydraulic pressure) is discharged from this state, the A piston stops pressing the friction plate, and the double-acting friction element is released. In this way, by allowing the A piston to stand by at a position where the friction plate clearance is zero (zero clearance position), the double-acting friction element can be fastened with high responsiveness, and the fastening shock can be suppressed. Can do.

JP2013-224716A

  However, in the vehicle (idle stop vehicle) in which idle stop control is performed in which the engine is automatically stopped when a predetermined stop condition is satisfied and the engine is restarted when the predetermined restart condition is satisfied in the engine automatic stop state (idle stop vehicle), When the elements are fastened at the starting stage, the following problems arise.

  During automatic engine stop by idle stop control, it is preferable to supply hydraulic pressure to the hydraulic chamber of the friction element that is fastened at the start stage in advance by an electric oil pump so that the vehicle can start quickly when the engine is restarted. For example, when the two friction elements fastened in the D range starting stage (first forward speed) are a friction element having a single piston / single hydraulic chamber and a double-acting friction element as described above When the engine is automatically stopped in the D range, the hydraulic pressure for engaging the friction element is supplied to the hydraulic chamber of the former friction element, and the first hydraulic pressure is supplied to the B chamber of the latter double-acting friction element. It is conceivable to discharge the hydraulic pressure in the A chamber. In this way, the former friction element is in the engaged state, and the A piston of the latter double-acting friction element is in the standby state at the zero clearance position. Then, only by supplying the second hydraulic pressure to the A chamber, The dynamic friction element is fastened with responsiveness, and thus the starting stage is achieved with responsiveness, so that the vehicle can start quickly when the engine is restarted.

  However, since the friction element is housed in the transmission case and is located higher than the oil pan that accumulates the hydraulic oil, negative pressure is generated in the A chamber when the hydraulic pressure is discharged from the A chamber when the engine is automatically stopped. The piston is shifted to the anti-friction plate side from the zero clearance position, and therefore, when the second hydraulic pressure is supplied to the A chamber at the time of restarting the engine, there is a concern that the double response type friction element may have a low fastening response and a fastening shock may occur. It is done.

  The present invention addresses the above-mentioned problem in an automatic transmission mounted on an idle stop vehicle, suppresses resetting of the zero clearance position of the pressing piston during engine automatic stop, and causes frictional elements when the engine is restarted. It is an object of the present invention to provide a control device for an automatic transmission that is securely fastened with good responsiveness and suppresses a fastening shock.

  In order to solve the above problems, the present invention provides a vehicle having an idle stop means for automatically stopping an engine when a predetermined stop condition is satisfied and restarting the engine when a predetermined restart condition is satisfied in an engine automatic stop state. A control device for an automatic transmission to be mounted, comprising: a friction element fastened at a start stage of the automatic transmission; and a hydraulic control means for controlling a hydraulic pressure for fastening the friction element, The friction element includes a friction plate, a pressing piston that presses the friction plate, and a clearance adjustment piston that supports the pressing piston so as to be relatively movable, and when the first hydraulic pressure is supplied to the clearance adjustment piston. When the clearance adjusting piston strokes, the pressing piston contacts the friction plate and the friction plate clearance becomes zero. When the second hydraulic pressure is supplied to the pressing piston from the state, the pressing piston presses the friction plate to be in a fastening state, and the hydraulic control means is an engine by the idle stop means. During the automatic stop, the first hydraulic pressure is supplied to the clearance adjusting piston, and the third hydraulic pressure that is lower than the second hydraulic pressure but does not generate a negative pressure in the hydraulic chamber of the pressing piston is supplied to the pressing piston. It is characterized by that.

  According to the present invention, when the first hydraulic pressure is supplied to the clearance adjustment piston of the friction element that is engaged at the start stage of the automatic transmission and the second hydraulic pressure is supplied to the pressing piston, the friction element is brought into the engaged state. When the engine is automatically stopped, the first hydraulic pressure is supplied to the clearance adjustment piston, and the third hydraulic pressure lower than the second hydraulic pressure is supplied to the pressing piston. By simply supplying the second hydraulic pressure to the piston for use, the friction element is fastened with high responsiveness and the fastening shock is suppressed.

  In that case, the hydraulic pressure is not discharged from the pressing piston, but a third hydraulic pressure is supplied to the pressing piston that is relatively low pressure but does not generate a negative pressure in the hydraulic chamber of the pressing piston. Generation of negative pressure in the pressing piston is prevented, and the zero clearance position of the pressing piston is maintained. Therefore, the problem that the pressing piston moves while the engine is automatically stopped and the zero clearance position is reset is suppressed, and the friction element is reliably fastened at the time of restarting the engine, and the fastening shock is suppressed.

  In the present invention, it is preferable that the hydraulic pressure control means discharges the third hydraulic pressure supplied to the pressing piston when the engine is restarted by the idle stop means.

  According to this configuration, the occurrence of a shock due to the output torque of the engine being input to the power transmission path when the engine is restarted is reduced. That is, as described above, in the present invention, a relatively low pressure oil pressure of the third oil pressure is supplied to the pressing piston even during the automatic engine stop so that the zero clearance position of the pressing piston is not reset during the automatic engine stop. . The third hydraulic pressure is lower than the second hydraulic pressure supplied when the friction element is engaged, but makes the friction element feel more engaged than when the hydraulic pressure is discharged from the pressing piston. Therefore, if the third hydraulic pressure is supplied to the pressing piston when the engine is restarted, the engine output torque may be input to the power transmission path and a shock may occur. Therefore, this configuration, when the engine is restarted, discharges the third hydraulic pressure that has been supplied so far to ensure that the friction element is released, in other words, the power transmission path is reliably cut off, The occurrence of the shock is reduced.

  In the present invention, it is preferable that the hydraulic pressure control means maintains the discharge of the third hydraulic pressure until the engine speed reaches a predetermined speed.

  According to this configuration, during the period from when the engine is restarted until the engine speed reaches the predetermined speed, the occurrence of the shock is reliably avoided.

  In the present invention, the friction element is preferably a brake element provided in a transmission case.

  According to this configuration, since the friction element is a double-acting friction element with excellent controllability and a brake element that is not affected by centrifugal hydraulic pressure, the fastening response of the friction element is further improved. .

  In the present invention, it is preferable that the brake element is a low reverse brake that is engaged at the first forward speed and the reverse speed.

  According to this configuration, since the engagement response of the low reverse brake is improved, it is possible to eliminate the one-way clutch at the start stage such as the first forward speed, and forward 1 when starting in the D range after the engine is restarted. The reverse speed when starting in the speed and the R range is reliably achieved with good responsiveness, and the vehicle can start quickly.

  In the present invention, there is provided an electric oil pump that generates hydraulic pressure to be supplied to the friction element of the automatic transmission during the automatic engine stop by the idle stop means, and the electric oil pump is configured so that the engine is in an idle stop state. It is preferable to drive the motor before it is automatically stopped.

  According to this configuration, the hydraulic oil is reliably supplied to the friction element by the electric oil pump during the automatic engine stop from the start of the automatic engine stop.

  The present invention provides a control device for an automatic transmission in which the friction element is securely fastened with high responsiveness when the engine is restarted and the fastening shock is suppressed. Therefore, the present invention is preferably applicable to an automatic transmission mounted on an idle stop vehicle. It is.

1 is a skeleton diagram of an automatic transmission according to an embodiment of the present invention. It is a fastening table | surface of the said automatic transmission. It is sectional drawing of the low reverse brake with which the said automatic transmission was equipped, and the state which supplied the hydraulic pressure to both A chamber and B chamber is shown. Similarly, the state where the hydraulic pressure is supplied only to the B chamber is shown. Similarly, the state in which the hydraulic pressure is discharged from both the A chamber and the B chamber is shown. It is a figure which shows the principal part of the hydraulic circuit with which the said automatic transmission was equipped. It is a control system figure of a vehicle provided with the above-mentioned automatic transmission. It is a time chart which shows an example of control operation in case the range of the above-mentioned automatic transmission is held in D range. It is a flowchart of the said control action. It is a time chart which shows an example of control operation in case the range of the said automatic transmission is switched from D range to N range.

(1) Configuration FIG. 1 is a skeleton diagram of an automatic transmission 1 according to this embodiment. The automatic transmission 1 automatically stops an engine (not shown) when a predetermined stop condition is satisfied, and performs a vehicle (idle stop) in which idle stop control is performed to restart the engine when a predetermined restart condition is satisfied in the engine automatic stop state. It is mounted on a stop vehicle.

  Examples of the stop condition include, for example, a basic condition that the brake pedal is depressed while the vehicle speed is substantially zero, and an additional condition that the remaining capacity of the battery is a predetermined amount or more. The difference between the set temperature of the air conditioner and the temperature in the passenger compartment is not more than a predetermined value. As the restart condition, for example, in the D range (forward travel range), the brake pedal is no longer depressed, and the non-travel range such as the N range (neutral range) and the P range (parking range). For example, an N → D selection operation or a P → D selection operation is performed.

  The automatic transmission 1 has an input shaft 2 to which engine output torque is input via a torque converter (not shown). First, second, and third planetary gear sets (hereinafter, “planetary gear sets” are simply referred to as “gear sets”) 10, 20, and 30 are arranged on the input shaft 2 from the engine side (right side in the figure). Low friction clutch 40, high clutch 50, low reverse brake (LR brake) (corresponding to "friction element" of the present invention) as friction elements for switching the power transmission path formed by these gear sets 10, 20, 30 60, 2nd and 6th speed brakes (26 brakes) 70, and reverse speed, 3rd speed and 5th speed brakes (R35 brakes) 80 are provided. These friction elements 40, 50, 60, 70, 80 are hydraulic. The low clutch 40 and the high clutch 50 selectively transmit the power from the input shaft 2 to the gear sets 10, 20, 30. The LR brake 60, the 26 brake 70, and the R35 brake 80 fix predetermined rotating elements of the gear sets 10, 20, and 30 to the transmission case 3.

  The gear sets 10, 20, 30 are all sun gears 11, 21, 31, pinions 12, 22, 32 that mesh with the sun gears 11, 21, 31, and carriers 13, 23, 33 that support the pinions 12, 22, 32. And ring gears 14, 24, 34 that mesh with the pinions 12, 22, 32.

  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. The carrier 23 of the second gear set 20 is connected to the output member 51 of the high clutch 50. A sun gear 31 of the third gear set 30 is connected to the input shaft 2. The output gear 4 is connected to the carrier 13 of the first gear set 10. The output gear 4 outputs the output torque of the automatic transmission 1 to the drive wheel side not shown.

  The ring gear 14 of the first gear set 10 and the carrier 23 of the second gear set 20 are coupled, and an LR brake 60 is interposed between these and the transmission case 3. The ring gear 24 of the second gear set 20 and the carrier 33 of the third gear set 30 are coupled, and a 26 brake 70 is interposed between the ring gear 24 and the transmission case 3. An R35 brake 80 is interposed between the ring gear 34 of the third gear set 30 and the transmission case 3.

  With the above configuration, the automatic transmission 1 has a forward 1st to 6th speed in the D range, as shown in FIG. 2, by a combination of the engagement states of the five friction elements 40, 50, 60, 70, and 80. Reverse speed in the R range (reverse running range) is achieved. As is apparent from FIG. 2, in this embodiment, the low clutch 40 and the LR brake 60 are engaged at the first forward speed (forward start stage), and the LR brake 60 and the R35 brake 80 are set at the reverse speed (reverse start stage). Is concluded. That is, the LR brake 60 is engaged at both the D range start stage and the R range start stage.

  As shown in FIGS. 3 to 5, the LR brake 60 is a double-acting friction element having a clearance adjusting function for improving controllability. The LR brake 60 includes a clearance adjusting piston (B piston) 62 and a pressing piston (A piston) 63. The B piston 62 is divided into a first piston member 62a and a second piston member 62b in order to improve the assemblability. After the assembly, the B piston 62 is integrated by a disc spring 60a, a snap ring 60b, and an annular fixing plate 60c. Yes.

  The B piston 62 is fitted in a cylinder 3a formed in the transmission case 3 so as to be capable of stroke in the axial direction. A hydraulic chamber (B chamber) 64 for the B piston 62 is formed between the B piston 62 and the transmission case 3. The B chamber 64 is supplied with hydraulic pressure (B chamber pressure) via a B chamber line 118 (see FIG. 6) formed in the transmission case 3.

  The A piston 63 is fitted inside the B piston 62 so as to be relatively movable in the axial direction. A hydraulic chamber (A chamber) 65 of the A piston 63 is formed between the A piston 63 and the B piston 62. The A chamber 65 is supplied with hydraulic pressure (A chamber pressure) via an A chamber line 119 (see FIG. 6) formed in the transmission case 3 and a communication hole 62c formed in the second piston member 62b.

  When a predetermined first hydraulic pressure (for example, several hundred kPa) is supplied to the B chamber 64 and a predetermined second hydraulic pressure (for example, several hundred kPa) is supplied to the A chamber 65, the hydraulic pressure is supplied to the colored portion in FIG. As shown in FIG. 4, the B piston 62 strokes to the left side of the drawing until it abuts against the stopper 67 against the urging force of the return spring 66 by the first hydraulic pressure, and the A piston 63. Further, the transmission case 3 and the braked member (that is, the member in which the ring gear 14 of the first gear set 10 and the carrier 23 of the second gear set 20 are coupled) are stroked to the left side of the drawing and are pressed by the second hydraulic pressure. The plurality of friction plates 68 that are alternately engaged with each other are pressed. Thereby, LR brake 60 will be in an engagement state.

  When the hydraulic pressure of the A chamber 65 (A chamber pressure) is discharged from this state, the pressing force of the A piston 63 is released while the A piston 63 is in contact with the friction plate 68 as shown in FIG. As a result, the LR brake 60 is released. At this time, the clearance of the friction plate 68 is zero, and the A piston 63 stands by at the zero clearance position.

  Further, when the hydraulic pressure in the B chamber 64 (B chamber pressure) is discharged from this state, the B piston 62 strokes to the right side of the drawing by the urging force of the return spring 66 as shown in FIG. At this time, due to the frictional force of the sealing member attached to the A piston 63, the A piston 63 moves to the right in the drawing together with the B piston 62 while maintaining the positional relationship with the B piston 62.

  Next time, when the LR brake 60 is engaged, first, hydraulic pressure is supplied to the B chamber 64. As a result, the A piston 63 and the B piston 62 make a stroke to the left in the figure while maintaining the positional relationship (see FIG. 4). At this time, the A piston 63 contacts the friction plate 68 and the clearance of the friction plate 68 becomes zero. That is, the A piston 63 enters a standby state at the zero clearance position. When the hydraulic pressure is supplied to the A chamber 65 from this state, the A piston 63 presses the friction plate 68 substantially simultaneously with the supply of the hydraulic pressure, and the LR brake 60 is fastened with good responsiveness (see FIG. 3).

  In short, when the LR brake 60 is engaged, the hydraulic pressure is supplied in the order of the B chamber 64 → A chamber 65, and when released, the hydraulic pressure is discharged in the order of the A chamber 65 → B chamber 64.

  FIG. 6 is a diagram showing a main part of the hydraulic circuit 100 provided in the automatic transmission 1. That is, the automatic transmission 1 includes a hydraulic circuit 100 for selectively supplying hydraulic pressure to the friction elements 40, 50, 60, 70, and 80 to achieve the respective shift stages shown in FIG. As described above, since the vehicle according to the present embodiment is an idle stop vehicle, in addition to the mechanical oil pump 102 that is driven by the engine to generate hydraulic pressure, the motor 101a is used during automatic engine stop by idle stop control. An electric oil pump 101 that is driven to generate hydraulic pressure is provided.

  Hydraulic pressure can be introduced into the hydraulic circuit 100 from both the mechanical oil pump 102 and the electric oil pump 101. The hydraulic circuit 100 includes a low clutch 40 (more specifically, its hydraulic chamber (not shown)) and an LR brake 60 (more specifically, the B chamber 64 and the A chamber 65 described above) in which the introduced hydraulic pressure is engaged at the first forward speed. ) As a valve for supplying to the pump), a pump switching valve 103, a manual valve 104, a first linear solenoid valve (first LSV) 105, a second linear solenoid valve (second LSV) 106, and a low reverse shift valve (LR shift valve) 107. , And an on / off solenoid valve (on / off SV) 108 is provided.

  The pump switching valve 103 switches which hydraulic pressure of the two pumps 101 and 102 is supplied to the two friction elements 40 and 60. The manual valve 104 is linked to the driver's range selection operation. The first LSV 105 controls the hydraulic pressure (low clutch pressure) supplied to the hydraulic chamber of the low clutch 40. The second LSV 106 controls the hydraulic pressure (A chamber pressure) supplied to the A chamber 65 of the LR brake 60. The LR shift valve 107 and the on / off SV 108 are arranged so that the hydraulic pressure supply / discharge sequence with respect to the B chamber 64 and the A chamber 65 of the LR brake 60 is determined when the LR brake 60 is fastened, as described above. When the hydraulic pressure is supplied and released, the hydraulic pressure is regulated so that the hydraulic pressure is discharged in the order of the A chamber 65 → the B chamber 64.

  The pump switching valve 103 has ports a and b for switching the position of the spool 103a at both ends in the axial direction. When the electric oil pump 101 is driven, the hydraulic pressure of the electric oil pump 101 is introduced into the port a on the left side of the figure, and the spool 103a is shifted to the right side as shown. When the mechanical oil pump 102 is driven, the hydraulic pressure of the mechanical oil pump 102 is introduced into the port b on the right side of the figure, and the spool 103a is shifted to the left side.

  The pump switching valve 103 further has input ports c and d and an output port e for the low clutch 40, and input ports f and g and an output port h for the LR brake 60. When the spool 103a is shifted to the right side, the port c and the port e for the low clutch 40 communicate with each other, and the port f and the port h for the LR brake 60 communicate with each other as illustrated. When the spool 103a is shifted to the left, the port d and the port e for the low clutch 40 communicate with each other, and the port g and the port h for the LR brake 60 communicate with each other.

  Oil paths 111 and 112 led from the electric oil pump 101 are connected to the input port c for the low clutch 40 and the input port f for the LR brake 60, respectively. Oil passages 113 and 114 led from the mechanical oil pump 102 are connected to the input port d for the low clutch 40 and the input port g for the LR brake 60, respectively. However, the oil passage 113 is guided from the mechanical oil pump 102 via the manual valve 104. The manual valve 104 communicates the mechanical oil pump 102 with the oil passage 113 when the D range and the R range are selected, and drains the oil passage 113 when the N range and the P range are selected. Let

  The low clutch line 115 led from the hydraulic chamber of the low clutch 40 is connected to the output port e for the low clutch 40 via the first LSV 105. An LR brake line 116 led from the LR shift valve 107 is connected to the output port h for the LR brake 60. A B chamber line 118 led from the B chamber 64 of the LR brake 60 is connected to the LR shift valve 107. The A chamber line 119 led from the A chamber 65 of the LR brake 60 is connected to the B chamber line 118 via the second LSV 106.

  Each of the first LSV 105 and the second LSV 106 has an input port i, an output port j, and a drain port k. The input port i and the output port j communicate with each other when opened, and the output port j and the drain port k when closed. To communicate.

  An oil passage 117 led from the mechanical oil pump 102 is connected to one end of the LR shift valve 107 in the axial direction via an on / off SV 108. The on-off SV 108 introduces the hydraulic pressure of the mechanical oil pump 102 to one end of the LR shift valve 107 when it is opened, shifts the spool (not shown) of the LR shift valve 107 to the right side, and the B chamber line 118 and the A chamber line. Drain 119. On the other hand, when the valve is closed, the spool is shifted to the left, and the LR brake line 116 is communicated with the B chamber line 118 and the A chamber line 119.

  As described above, the LR brake 60 is engaged only at the first forward speed and the reverse speed with relatively low use frequency and use time. For this reason, the ON / OFF SV 108 has an open state in which the B chamber line 118 and the A chamber line 119 are drained longer than a closed state in which the LR brake line 116 and the B chamber line 118 and the A chamber line 119 are communicated. . Therefore, in the present embodiment, the normally open type on / off SV 108 that is open when not energized (OFF) is employed. As a result, the power consumption of the on / off SV 108 can be reduced, and the fuel efficiency is improved.

  FIG. 7 is a control system diagram of an idle stop vehicle provided with the automatic transmission 1. The control device 200 is a microprocessor including a CPU, a ROM, a RAM, and the like, and corresponds to the “idle stop unit” and the “hydraulic control unit” of the present invention.

  The control device 200 receives the signal from the range sensor 201 that detects the range of the automatic transmission 1 selected by the driver, the signal from the vehicle speed sensor 202 that detects the vehicle speed of the vehicle, and the amount of operation of the driver's accelerator pedal. A signal from the accelerator operation amount sensor 203 to be detected, a signal from the brake switch 204 to detect the depression of the brake pedal of the driver, a signal from the engine speed sensor 205 to detect the engine speed, and the electric oil pump 101 A signal is input from an electric oil pump rotation speed sensor 206 that detects the rotation speed.

  Based on these signals, the control device 200 outputs control signals to the engine fuel supply device 211, the ignition device 212, and the starter 213 in order to perform idle stop control. In addition, in order to perform hydraulic control of the low clutch 40 and the LR brake 60 of the automatic transmission 1 during idle stop control, a control signal is output to the electric oil pump motor 101a and the hydraulic circuit 100 of the automatic transmission 1 is controlled. Control signals are output to the first LSV 105, the second LSV 106, and the on / off SV 108.

  FIG. 8 is a time chart illustrating an example of a control operation performed by the control device 200. This time chart shows changes in various signals and state quantities from before the vehicle stops until after starting. The control device 200 performs idle stop control and hydraulic control of the low clutch 40 and the LR brake 60 while the vehicle is stopped. The example of FIG. 8 is a case where the range of the automatic transmission 1 is held in the D range during the idle stop control.

  In FIG. 8, time t1 is the time when the idle stop state flag changes from 0 to 1, time t2 is the time when the flag changes from 1 to 2, time t3 is the time when the flag changes from 2 to 3, and time t4 is the engine time The time t5 when the engine speed after the restart reaches the predetermined reference speed N1 is the time when the vehicle starts.

  Until time t1, the vehicle is traveling forward in the D range. The forward speed of the shift stage of the automatic transmission 1 is achieved. That is, the hydraulic pressure (engaged hydraulic pressure) for engaging the low clutch 40 is supplied to the hydraulic chamber of the low clutch 40, the first hydraulic pressure is supplied to the B chamber 64 of the LR brake 60, and the first hydraulic pressure is supplied to the A chamber 65. Two hydraulic pressures are supplied, and both the low clutch 40 and the LR brake 60 are engaged.

  Since the mechanical oil pump (OP) 102 is driven by the engine to generate hydraulic pressure, and the electric oil pump (OP) 101 does not generate hydraulic pressure by turning off the motor 101a, the spool 103a of the pump switching valve 103 is shown in FIG. To the left side (denoted as “mechanical OP side” in FIG. 8), and the hydraulic pressure generated by the mechanical pump 102 is transferred to the low clutch via the oil passages 113, 114, the low clutch line 115 and the LR brake line 116. 40 and LR brake 60 are supplied.

  The on / off SV 108 is ON (energized). As a result, the normally open type on / off SV 108 is closed, the spool of the LR shift valve 107 is shifted to the left in FIG. 6, and the LR brake line 116, the B chamber line 118, and the A chamber line 119 communicate with each other. The on / off SV 108 is turned off (non-energized) at gear speeds other than the first forward speed and the reverse speed at which the LR brake 60 is engaged.

  In this state, as the accelerator operation amount decreases, the vehicle speed, the engine speed, and the turbine speed (the output speed of the torque converter, which is the same as the speed of the input shaft 2 of the automatic transmission 1) decrease. When the brake pedal is depressed and the vehicle stops, for example, waiting for an intersection signal (vehicle speed and turbine speed = 0), the idle stop state flag changes from 0 to 1 (time t1). At this time, among the stop conditions of the idle stop control, the basic condition that the brake pedal is depressed with the vehicle speed being substantially zero is satisfied.

  When the basic condition is satisfied, the control device 200 turns on the motor 101a and starts driving the electric oil pump 101. As a result, the electric oil pump 101 is driven by the motor 101a to generate hydraulic pressure. The generated hydraulic pressure is guided to the pump switching valve 103, the spool 103 a is shifted to the right side of FIG. 6 (denoted as “electric OP side” in FIG. 8), and the hydraulic pressure generated by the electric oil pump 101 is oil paths 111, 112. Are supplied to the low clutch 40 and the LR brake 60 via the low clutch line 115 and the LR brake line 116. At this time, the low oil pressure of the electric oil pump 101 is supplied to the low clutch 40 and the LR brake 60, which was previously supplied with the hydraulic pressure of the mechanical oil pump 102.

  Next, among the stop conditions for the idle stop control, the control device 200 adds that the remaining capacity of the battery is a predetermined amount or more, and that the difference between the set temperature of the air conditioner and the temperature in the passenger compartment is equal to or less than a predetermined value It is determined whether or not the target condition is satisfied, in other words, whether or not the engine can be stopped. As a result, when the additional condition is satisfied, the idle stop state flag changes from 1 to 2 (time t2). With this, the control device 200 automatically stops the engine. As the engine stops, the mechanical oil pump 102 stops generating the hydraulic pressure, but as described above, the hydraulic pressure of the electric oil pump 101 is already supplied to the low clutch 40 and the LR brake 60 at this time. There is no.

  The control device 200 controls the second LSV 106 together with the automatic engine stop to reduce the A chamber pressure of the LR brake 60 from the second hydraulic pressure to the third hydraulic pressure. The third hydraulic pressure is lower than the second hydraulic pressure (for example, several tens of kPa). Therefore, the A piston 63 stops pressing the friction plate 68 and the LR brake 60 is released. As a result, the first forward speed is not achieved, and the power transmission path of the automatic transmission 1 is interrupted. In FIG. 8, the symbol “α” indicates a period during which the power transmission path of the automatic transmission 1 is interrupted (non-achievement period of the first forward speed). By setting the A chamber pressure to a low pressure state, the electric oil consumption of the electric oil pump 101 can be reduced, and the fuel consumption performance is improved.

  If necessary, the control device 200 supplies the engagement hydraulic pressure to the hydraulic chamber of the low clutch 40, supplies the first hydraulic pressure to the B chamber 64 of the LR brake 60, and automatically transmits the first hydraulic pressure to the A chamber 65 of the LR brake 60. The third hydraulic pressure that is lower than the second hydraulic pressure but does not generate a negative pressure in the A chamber 65 is supplied. The third hydraulic pressure is a hydraulic pressure that puts the LR brake 60 in a released state, but is a hydraulic pressure that can hold the zero clearance position of the A piston 63 in the released LR brake 60. Such a value of the third hydraulic pressure is experimentally obtained in advance (for example, a value of 0 kPa or more).

  On the other hand, as shown by a chain line (symbol X) in FIG. 8, when the hydraulic pressure is discharged from the A chamber 65 of the LR brake 60 during the automatic engine stop, a negative pressure is generated in the A chamber 65 and the A piston 63 becomes zero. There arises a problem that the clearance position shifts to the side opposite to the friction plate. More specifically, as is apparent from FIG. 6, the hydraulic oil discharged from the A chamber 65 is discharged from the drain port k of the second LSV 106 to the oil pan (not shown) via the A chamber line 119. The oil pan is provided on the cylinder block of the engine and the lower surface of the transmission case 3. Further, the second LSV 106 is immersed in the hydraulic oil accumulated in the oil pan so as not to bite air. Therefore, the drain port k of the second LSV 106 is at a position lower than the A chamber 65 of the LR brake 60 housed in the transmission case 3. As a result, as the hydraulic pressure is discharged from the A chamber 65, the inside of the A chamber 65 becomes a negative pressure.

  Next, the control device 200 determines whether or not the restart condition in the D range that the brake pedal is not depressed is satisfied among the restart conditions of the idle stop control, in other words, the driver intends to start. It is determined whether it is shown. As a result, when the restart condition is satisfied, the idle stop state flag changes from 2 to 3 (time t3). With this, the control device 200 restarts the engine.

  As the engine restarts, the mechanical oil pump 102 is driven by the engine to resume the generation of hydraulic pressure. The control device 200 turns off the motor 101a and stops driving the electric oil pump 101 when the hydraulic pressure of the mechanical oil pump 102 has sufficiently increased (determined by a hydraulic switch or time not shown). As a result, the spool 103a of the pump switching valve 103 is again shifted to the mechanical OP side, and the hydraulic pressure of the mechanical oil pump 102 is supplied to the low clutch 40 and the LR brake 60.

  The control device 200 controls the second LSV 106 together with the engine restart, and discharges the A chamber pressure (third hydraulic pressure) of the LR brake 60 as indicated by reference numeral A in FIG. This is to reduce the occurrence of shock due to the output torque of the engine being input to the power transmission path. The control device 200 maintains the discharge of the third hydraulic pressure until the engine speed reaches a predetermined reference speed N1 (until time t4). Such a value of the reference rotational speed N1 is experimentally obtained in advance from the viewpoint of the shock reduction. The control device 200 increases the A chamber pressure of the LR brake 60 toward the second hydraulic pressure at time t4. As a result, the A piston 63 presses the friction plate 68 substantially simultaneously with the supply of the hydraulic pressure, and the LR brake 60 enters the engaged state with good responsiveness. Therefore, the first forward speed is achieved, and the power transmission path of the automatic transmission 1 that has been shut off is formed again at time t4, as indicated by the symbol α.

  Since the brake pedal has not been depressed at this time, the vehicle speed gradually increases after time t4 due to the reconfiguration of the power transmission path. At time t5, the driver depresses the accelerator pedal, and the vehicle starts. Further, the turbine rotational speed increases in conjunction with the engine rotational speed before time t4 when the power transmission path is reformed, and increases in conjunction with the vehicle speed after time t4.

  Since the time for discharging the A chamber pressure to reduce the shock (the time from engine restart until the engine speed reaches the reference speed N1) is very short, the return of the A piston 63 is minimized and the shock is reduced. Both reduction and controllability are improved.

  FIG. 9 is a flowchart showing the control operation of FIG. 8 performed by the control device 200. However, only the main characteristic processing is extracted and shown.

  In step S1, control device 200 determines whether or not the idle stop state flag has changed from 0 to 1. If YES (time t1 in FIG. 8), control device 200 drives electric oil pump 101 in step S2. Start.

  Next, in step S3, control device 200 determines whether or not the idle stop state flag has changed from 1 to 2, and if YES (time t2 in FIG. 8), the engine is automatically stopped in step S4. Thereafter, when the engine speed becomes equal to or lower than a predetermined threshold, the A chamber pressure of the LR brake 60 is decreased from the second hydraulic pressure to the third hydraulic pressure.

  Next, in step S5, control device 200 determines whether or not the idle stop state flag has changed from 2 to 3. If YES (time t3 in FIG. 8), the control device 200 restarts the engine in step S6. And the A room pressure of LR brake 60 is discharged (code a of Drawing 8).

  Next, in step S7, the control device 200 determines whether or not the engine speed has become a predetermined reference speed N1 or more. If YES (time t4 in FIG. 8), the LR brake 60 is determined in step S8. The A chamber pressure is increased toward the second hydraulic pressure.

(2) Operation As described above in detail with reference to the drawings, the control device for the automatic transmission 1 according to the present embodiment automatically stops the engine when a predetermined stop condition is satisfied, It is mounted on a vehicle (idle stop vehicle) having a control device 200 that performs idle stop control for restarting the engine when the restart condition is satisfied. The automatic transmission 1 includes a low clutch 40 and an LR brake 60 that are engaged at a first forward speed (forward start speed), and the control device 200 is configured to apply hydraulic pressure for engaging the low clutch 40 and the LR brake 60. Control is performed (FIGS. 6 and 7).

  The LR brake 60 includes a friction plate 68, a pressing piston 63 that presses the friction plate 68, and a clearance adjustment piston 62 that supports the pressing piston 63 so as to be relatively movable, and is configured as follows. (FIGS. 3 to 5). When the first hydraulic pressure is supplied to the clearance adjustment piston 62, the clearance adjustment piston 62 strokes. As a result, the pressing piston 63 contacts the friction plate 68 and the clearance of the friction plate 68 becomes zero. When the second hydraulic pressure is supplied to the pressing piston 63 from this state, the pressing piston 63 presses the friction plate 68. As a result, the LR brake 60 is engaged.

  While the engine is automatically stopped by the idle stop control, the control device 200 supplies the low clutch 40 with an engagement hydraulic pressure for engaging the low clutch 40 and supplies the clearance adjustment piston 62 with the first hydraulic pressure. Then, a third hydraulic pressure that is lower than the second hydraulic pressure but does not generate a negative pressure in the hydraulic chamber 65 of the pressing piston 63 is supplied to the pressing piston 63 (FIG. 8).

  According to this configuration, if the fastening hydraulic pressure is supplied to the low clutch 40, the first hydraulic pressure is supplied to the clearance adjustment piston 62 of the LR brake 60, and the second hydraulic pressure is supplied to the pressing piston 63 of the LR brake 60, In the automatic transmission 1 in which the low clutch 40 and the LR brake 60 are both engaged and the first forward speed is achieved, the engagement hydraulic pressure is supplied to the low clutch 40 and the clearance adjusting piston 62 is supplied during automatic engine stop. Since the first hydraulic pressure is supplied to the pressing piston 63 and the third hydraulic pressure lower than the second hydraulic pressure is supplied to the pressing piston 63, the LR brake is simply supplied to the pressing piston 63 when the engine is restarted. 60 is fastened with responsiveness, and as a result, the first forward speed is achieved with good responsiveness, and the fastening shock is suppressed.

  In addition, in this case, the third hydraulic pressure is not discharged from the pressing piston 63 but a relatively low pressure is generated in the pressing piston 63 but no negative pressure is generated in the hydraulic chamber 65 of the pressing piston 63. Since it is supplied, negative pressure is prevented from being generated in the pressing piston 63, and the zero clearance position of the pressing piston 63 is maintained. Therefore, the problem that the pressing piston 63 moves during the automatic engine stop and the zero clearance position is reset is suppressed, and the LR brake 60 is securely fastened when the engine is restarted. It is achieved with good responsiveness and the fastening shock is suppressed.

  In the present embodiment, the control device 200 discharges the third hydraulic pressure supplied to the pressing piston 63 when the engine is restarted by the idle stop control (reference number A in FIG. 8).

  According to this configuration, the occurrence of a shock due to the output torque of the engine being input to the power transmission path when the engine is restarted is reduced. That is, as described above, in the present embodiment, a relatively low pressure hydraulic pressure called the third hydraulic pressure is applied to the pressing piston 63 during the automatic engine stop so that the zero clearance position of the pressing piston 63 is not reset during the automatic engine stop. Supply. Although the third hydraulic pressure is lower than the second hydraulic pressure supplied when the LR brake 60 is engaged, the third hydraulic pressure is lower than that when the hydraulic pressure is discharged from the pressing piston 63 (reference numeral X in FIG. 8). It seems to be a conclusion. Therefore, if the third hydraulic pressure is supplied to the pressing piston 63 when the engine is restarted, the engine output torque may be input to the power transmission path and a shock may occur. Therefore, this configuration, when the engine is restarted, discharges the third hydraulic pressure that has been supplied so far and reliably releases the LR brake 60, in other words, ensures that the power transmission path is shut off, The occurrence of the shock is reduced.

  In the present embodiment, the control device 200 maintains the discharge of the third hydraulic pressure until the engine speed reaches a predetermined reference speed N1 (until time t4 in FIG. 8).

  According to this configuration, during the period from when the engine is restarted until the engine speed reaches the reference speed N1, the occurrence of the shock is reliably avoided.

  In the present embodiment, the LR brake 60 is a brake element provided in the transmission case 3.

  According to this configuration, the LR brake 60 is a double-acting friction element that is excellent in controllability, and is a brake element that is not affected by the centrifugal hydraulic pressure, so that the engagement response of the LR brake 60 is further improved. .

  In the present embodiment, the LR brake 60 is fastened at the first forward speed (forward start stage) and the reverse speed (reverse start stage) (FIG. 2).

  According to this configuration, since the engagement response of the LR brake 60 is improved, the one-way clutch can be eliminated at the first forward speed, and the first forward speed when starting in the D range after the engine is restarted is ensured. Achieved with good responsiveness, the vehicle can start quickly.

  In the present embodiment, an electric oil pump 101 that generates hydraulic pressure supplied to the low clutch 40 and the LR brake 60 during engine automatic stop by the idle stop control is provided. At this time, the engine is driven before it is automatically stopped (FIG. 8).

  According to this configuration, the hydraulic oil supply to the low clutch 40 and the LR brake 60 by the electric oil pump 101 during the automatic engine stop is reliably performed from the start point of the automatic engine stop (time t2 in FIG. 8).

(3) Modified Example Next, a modified example of the above embodiment will be described with reference to FIG. In the above embodiment, during the idle stop control, the range of the automatic transmission 1 is maintained in the D range, and the engine is restarted when the brake pedal is not depressed (D range restart). In this modified example, during the idle stop control, the range of the automatic transmission 1 is switched from the D range to the N range, and then the engine is restarted when the N → D selection operation is performed (N → D). Select restart).

  Also in this case, the control device 200 basically performs the same control operation as in the above embodiment. In FIG. 10, times t1 'to t5' are the same as t1 to t5 in FIG. The difference from the above embodiment is that the range of the automatic transmission 1 is switched from the D range to the N range during idle stop control (between times t2 'and t3'). In this case, the idle stop proceeds in the N range, and then the N → D selection operation is performed, whereby the restart condition in the N range is satisfied, and the idle stop state flag changes from 2 to 3 (time t3 ′). ).

  In this modification, the brake pedal is depressed until the start (time t5 '). Therefore, even if the power transmission path is re-formed at time t4 ', the vehicle speed does not rise. Further, the turbine rotational speed increases in conjunction with the engine rotational speed before time t4 'when the power transmission path is re-formed, and once becomes zero after time t4'. Then, the driver stops the depression of the brake pedal, and the vehicle speed and the turbine speed increase simultaneously with the start of the vehicle when the accelerator pedal is depressed (time t5 ').

  Even in this modification, the flowchart of FIG. 9 is applied as it is. However, when the range is switched to the N range during the idle stop control, the manual valve 104 drains the oil passage 113 in FIG. Since it is supplied, there is no problem and the fastening hydraulic pressure continues to be supplied to the low clutch 40 without any trouble.

  In the above embodiment, the engine starts in the D range after restarting the engine. However, the LR brake 60 is engaged not only at the first forward speed (forward start stage) but also at the reverse speed (reverse start stage). The present invention can also be applied when starting in the R range after the engine is started. As a result, the reverse speed when starting in the R range after the engine restart is reliably achieved with good responsiveness, and the fastening shock is suppressed.

  Further, since the hydraulic circuit 100 is in the same state as the N range except that the output gear 4 of the automatic transmission 1 is mechanically locked, the P range may be the P range instead of the N range in FIG. That is, the present invention can be applied to N → R select restart, P → D select restart, P → R select restart, and the like in addition to the D range restart and N → D select restart.

1 Automatic transmission 3 Transmission case 40 Low clutch 60 Low reverse brake (friction element)
62 Clearance adjustment piston (B piston)
63 Piston for pressing (A piston)
64 B chamber (clearance adjustment piston hydraulic chamber)
65 A chamber (hydraulic chamber of piston for pressing)
68 Friction plate 101 Electric oil pump 102 Mechanical oil pump 200 Control device (idle stop means, hydraulic control means)

Claims (6)

A control device for an automatic transmission mounted on a vehicle having idle stop means for automatically stopping the engine when a predetermined stop condition is satisfied and restarting the engine when the predetermined restart condition is satisfied in the engine automatic stop state,
A friction element that is fastened at the starting stage of the automatic transmission;
Hydraulic control means for controlling the hydraulic pressure for fastening the friction element,
The friction element is
A friction plate, a pressing piston that presses the friction plate, and a clearance adjustment piston that supports the pressing piston so as to be relatively movable;
When the first hydraulic pressure is supplied to the clearance adjustment piston, the clearance adjustment piston makes a stroke so that the pressing piston comes into contact with the friction plate, and the clearance of the friction plate becomes zero. From this state, the pressing piston When the second hydraulic pressure is supplied to the pressure piston, the pressing piston presses the friction plate to be in a fastening state,
The hydraulic control means supplies the first hydraulic pressure to the clearance adjusting piston during the automatic engine stop by the idle stop means, and the hydraulic pressure chamber of the pressing piston is lower than the second hydraulic pressure to the pressing piston. A control device for an automatic transmission, wherein a third hydraulic pressure that does not generate negative pressure is supplied to the automatic transmission. The control apparatus for an automatic transmission according to claim 1,
The control apparatus for an automatic transmission, wherein the hydraulic control means discharges the third hydraulic pressure supplied to the pressing piston when the engine is restarted by the idle stop means. The control apparatus for an automatic transmission according to claim 2,
The control apparatus for an automatic transmission, wherein the hydraulic pressure control means maintains the discharge of the third hydraulic pressure until the engine speed reaches a predetermined speed. The control device for an automatic transmission according to any one of claims 1 to 3,
The control apparatus for an automatic transmission, wherein the friction element is a brake element provided in a transmission case. The control apparatus for an automatic transmission according to claim 4,
The control device for an automatic transmission, wherein the brake element is a low reverse brake that is engaged at a first forward speed and a reverse speed. The control apparatus for an automatic transmission according to any one of claims 1 to 5,
An electric oil pump that generates hydraulic pressure supplied to the friction element of the automatic transmission during automatic engine stop by the idle stop means;
The control apparatus for an automatic transmission, wherein the electric oil pump is driven before the engine is automatically stopped at the time of idling stop.

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