JP2007270954A - Hydraulic control device for automatic transmission - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent shock at a time of restart while securing restart response at a time of engine restart after idling stop. <P>SOLUTION: A hydraulic control device for an automatic transmission provided with an idling stop control means stopping an engine when a predetermined condition is satisfied, is provided with a first oil channel discharging working oil from an engagement element for start, a second oil channel supplying working oil from an oil pump to the engagement element for start, and a third oil channel discharging working oil from the engagement element for starting when a shift position other than start position is selected. The first oil channel is provided with a pressure hold valve holding fastening hydraulic pressure of a fastening element for starting during oil pump non-operation time, the second oil channel is provided with a check valve inhibiting circulation of working oil to the oil pump from the fastening element for starting , and load applied to the piston by the hold fastening hydraulic pressure is higher than elastic force of a return spring when the clearance is at the maximum. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a hydraulic control device for an automatic transmission, and more particularly to a hydraulic control device for a starting fastening element.

  In an automatic transmission that is supplied with hydraulic pressure for engaging a clutch (including a brake, the same applies hereinafter) by hydraulic pressure generated by an oil pump driven by the engine, the oil is kept while the engine is stopped due to idle stop. The pump cannot generate hydraulic pressure. For this reason, immediately after the engine is restarted after the idle stop, the start clutch engagement hydraulic pressure becomes zero, and the start clutch is not engaged. Therefore, since engine power cannot be transmitted to the wheels, there is a problem in that the restart response is delayed. Further, when the engine is restarted, there is a problem that a fastening shock occurs when the starting clutch is suddenly engaged while the engine speed is increasing (overshoot) due to the accelerator pedal being depressed.

As a prior art capable of solving the above problem, Non-Patent Document 1 provides an electric pump separately from an oil pump driven by an engine, and during idle stop, the forward clutch is brought into an engaged state by the hydraulic pressure supplied by the electric pump. The method of keeping is described. Further, in Patent Document 1, a check valve and an accumulator (or an electric pump) are provided between the oil pump and the clutch hydraulic unit separately from the oil pump driven by the engine, and this accumulator is used during idle stop. A method is described in which the forward clutch is kept in the engaged state by the supply hydraulic pressure of the (or electric pump). Further, in Non-Patent Document 2, a check valve is provided on the supply oil path to the forward clutch and a discharge valve is provided on the discharge oil path from the forward clutch, and the hydraulic circuit of the forward clutch is closed during idle stop. Thus, there is described a method for keeping the forward clutch in the engaged state. The opening and closing of the discharge valve is controlled by a cam mechanism interlocked with the operation of the shift lever.
JP-A-8-14076 Automobile Engineering Society Lecture Preprints No.59-03 SAE TECHNICAL PAPER SERIES 2001-01-0326

  However, in the methods described in Non-Patent Document 1 and Patent Document 1, the forward clutch is completely engaged when the engine is stopped, and the torque capacity of the forward clutch is maximized. For this reason, when the engine speed increases (overshoot) when the engine is restarted, the increase in engine torque is directly transmitted to the transmission output shaft, giving the driver a sudden feeling of jumping out of the vehicle. In the method described in Non-Patent Document 2, when the idle stop is performed in the D range, the forward clutch engagement hydraulic pressure before the idle stop is maintained. Occasionally, it gives the driver a sudden feeling of jumping out of the vehicle even though the accelerator opening is zero. Therefore, in these methods, in order to avoid the above-mentioned feeling of popping out, it is necessary to take measures such as preventing the feeling of popping out of the vehicle by automatic braking during the overshoot period of the engine speed.

  Further, in the methods described in Non-Patent Document 1 and Patent Document 1, it is necessary to provide a clutch engagement hydraulic pressure supply means that does not depend on the driving force of the engine, such as an accumulator or an electric pump. Further, in order to completely discharge the hydraulic oil supplied to the clutch, it is necessary to provide clutch engagement hydraulic pressure discharge means such as a solenoid valve. Therefore, vehicle mountability and cost deteriorate. On the other hand, in the method described in Non-Patent Document 2 that does not use an accumulator or an electric pump, a normal manual valve that selectively supplies a fastening hydraulic pressure to a required fastening element in conjunction with the operation of a shift lever is provided in parallel with the cam mechanism. It is necessary to provide in. Therefore, it is disadvantageous in terms of layout. As described above, these methods have problems in terms of vehicle mountability, cost, and layout.

  Furthermore, in the method described in Non-Patent Document 1 and the method using the electric pump described in Patent Document 1, since power is consumed even during idle stop, whether or not idle stop is permitted while constantly monitoring the charge state of the battery. It is necessary to determine whether.

  The present invention has been made paying attention to the above-mentioned problems, while preventing re-start shock while ensuring re-start response at the time of engine restart after idling stop, and mounting on vehicle and cost, An object of the present invention is to provide a hydraulic control device for an automatic transmission capable of improving the layout.

  In order to achieve the above object, a hydraulic control device for an automatic transmission according to claim 1 includes a piston that moves by supplying hydraulic oil from an oil pump driven by an engine and an input that is pressed against each other by movement of the piston. And a plurality of friction plates on the output side and a return spring that secures a predetermined clearance between the piston and the plurality of friction plates by elastic force when not fastened, and the start position is selected as the shift position In a hydraulic control device for an automatic transmission, comprising: a starting fastening element that is fastened when a predetermined condition is satisfied; and an idle stop control means that stops an engine when a predetermined condition is satisfied. A first oil passage for discharging oil, a second oil passage for supplying hydraulic oil from the oil pump to the starting fastening element, and a passage other than the starting position. And a third oil passage for discharging hydraulic oil from the starting fastening element when the oil pump position is selected, and fastening the starting fastening element on the first oil passage when the oil pump is not operated A pressure holding valve for holding hydraulic pressure is provided to permit the hydraulic oil to flow from the oil pump to the starting fastening element on the second oil passage, and for the hydraulic oil to flow from the starting fastening element to the oil pump. A check valve that prohibits circulation is provided, and the load applied to the piston by the held hydraulic pressure is greater than the elastic force of the return spring when the clearance is maximum.

  Therefore, in the hydraulic control device for an automatic transmission according to the present invention, it is possible to prevent a shock at the time of restart while ensuring the restart response at the time of engine restart after an idle stop, and to reduce the vehicle mounting performance and cost. It is possible to improve the surface and the layout surface.

  Hereinafter, the best mode for realizing the present invention will be described based on a first embodiment.

[Outline of automatic transmission]
FIG. 1 is a schematic cross-sectional view of an automatic transmission for an FF vehicle to which a hydraulic control device of the present invention is applied. FIG. 2 shows a control system of the automatic transmission. The automatic transmission includes a torque converter 1 that amplifies torque from an engine (not shown), a forward / reverse switching mechanism 2 having a starting clutch (forward clutch and reverse brake), a CVT 3 that continuously changes speed between input and output, and a drive. A gear 4, an idler gear 4a, a final gear 4b, and a differential device 4c are provided. Further, an oil pump 7 and a hydraulic control valve unit 8 are provided as a mechanism for supplying hydraulic pressure and lubricating oil to each device.

  The forward / reverse switching mechanism 2 is constituted by a planetary gear mechanism including a ring gear 2a, a pinion carrier 2b, and a sun gear 2c. Ring gear 2 a is connected to torque converter output shaft 13. The sun gear 2 c is connected to the CVT input shaft 14. The pinion carrier 2b is provided with a reverse brake 2e for fixing the pinion carrier 2b to the transmission case, and a forward clutch 2d for integrally connecting the CVT input shaft 14 and the pinion carrier 2b.

  The CVT 3 includes a primary pulley 30 (primary movable pulley 30a and primary fixed pulley 30b) provided at the end of the CVT input shaft 14, and a secondary pulley 31 (secondary movable pulley 31a and secondary fixed pulley provided on the driven shaft 16). 31b) and a belt 15 that is wound between the grooves of the pulleys 30 and 31 and transmits the rotational force of the primary pulley 30 to the secondary pulley 31.

  The axial position of the primary movable pulley 30a (the groove width of the primary pulley 30) is defined by the hydraulic pressure acting on the primary pulley cylinder chamber 30c and the primary clamp chamber 30d. The axial position of the secondary movable pulley 31a (the groove width of the secondary pulley 31) is defined by the hydraulic pressure acting on the secondary pulley cylinder chamber 31c and the secondary clamp chamber 31d.

(CVT pulley piston chamber structure)
Here, the piston chamber structure of the primary pulley 30 and the secondary pulley 31 is demonstrated based on FIG.

  The primary pulley cylinder chamber 30c is partitioned by a primary movable pulley 30a, an extension 30e of the primary movable pulley 30a, and a fixed wall 30f. The inner periphery of the extension 30e and the outer periphery of the fixed wall 30f are sealed. Therefore, even if the primary movable pulley 30a moves in the axial direction, the primary pulley cylinder chamber 30c maintains a liquid-tight state.

  The primary clamp chamber 30d is partitioned by fixed walls 30f and 30g and a piston 30h. The outer diameter portion of the piston 30h contacts the extension portion 30e of the primary movable pulley 30a. The piston 30h maintains the primary clamp chamber 30d in a liquid-tight state by a seal.

  The piston chamber structure of the secondary pulley 31 is the same as that of the primary pulley 30.

  A centrifugal cancel chamber 31i is provided between the secondary pulley cylinder chamber 31c and the secondary clamp chamber 31d. The centrifugal cancel chamber 31i cancels the centrifugal hydraulic pressures of both the secondary pulley cylinder chamber 31c and the secondary clamp chamber 31d.

  The pressure receiving areas of the primary pulley cylinder chamber 30c and the secondary pulley cylinder chamber 30c are made equal. Further, the pressure receiving areas of the primary clamp chamber 30d and the secondary clamp chamber 31d are made equal, and both the chambers 30d and 31d communicate with each other through an oil passage 70. As will be described later, a line pressure is supplied to both chambers 30d and 31d.

  Accordingly, since the highest line pressure in the hydraulic circuit is supplied to the clamp chambers 30d and 31d, the power of the oil pump 7 can be used efficiently, and belt slip can be reliably prevented. .

  A drive gear 4 is fixed to the driven shaft 16, and this drive gear 4 drives a drive shaft reaching an unillustrated wheel via an idler gear 4a, a differential device 4c, and a final gear 4b provided on the idler shaft 4d. To do.

  During the power transmission as described above, the primary movable pulley 30a and the secondary movable pulley 31a are moved in the axial direction to change the contact position radius with the belt 15, thereby rotating between the primary pulley 30 and the secondary pulley 31. The ratio, that is, the gear ratio is changed. Such control to change the width of the pulley groove is performed by hydraulic control to the primary pulley cylinder chamber 30c, the secondary pulley cylinder chamber 31c, the primary clamp chamber 30d, and the secondary clamp chamber 31d via the CVT control unit 9.

  The secondary pulley cylinder chamber 31c is provided with a spring 31j, and the secondary movable pulley 31a is pivoted by the elastic force of the spring 31j even when the primary pulley 30 and the secondary pulley 31 are not supplied with hydraulic pressure when the engine is not operating. It is moved in the direction to realize a predetermined pulley ratio (low) and ensure a pulley torque capacity.

  The CVT control unit 9 includes a throttle opening TVO from the throttle opening sensor 5a, an engine rotation speed Ne from the engine rotation speed sensor 5b, an oil temperature T from the oil temperature sensor 5c, and a primary rotation from the primary rotation speed sensor 6a. The number Npri, the secondary rotational speed Nsec from the secondary rotational speed sensor 6b, and the like are input. A control signal is calculated based on this input signal, and a control signal is output to a hydraulic control valve unit 8 using an oil pump 7 driven by the engine as a hydraulic source.

  A control signal from the CVT control unit 9 is input to the hydraulic control valve unit 8, and a solenoid in the hydraulic control valve unit 8 is driven based on this control signal. Thus, the shift pressure is controlled by supplying the control pressure to each cylinder chamber and the clamp chamber, and the engagement hydraulic pressure supplied to the forward clutch 2d and the reverse brake 2e is controlled.

(Forward clutch)
FIG. 3 is a sectional view of the forward clutch 2d in the CVT input shaft 14 direction. The forward clutch 2d is connected to the torque converter output shaft 13 so as to rotate integrally therewith, the clutch hub 51 connected to the sun gear 2c and rotated integrally, and a plurality of input side friction plates 50a that are spline-fitted to the clutch drum 50. The clutch hub 51 includes a plurality of output side friction plates 51a that are spline-fitted, a clutch piston 52, a disc spring 53, a clutch return spring 54, and a spring retainer 55.

  For the sake of explanation, the x-axis is set in the axial direction of the CVT input shaft 14 and the direction in which the spring retainer 55 is provided with respect to the clutch piston 52 is defined as the positive direction. A forward clutch piston chamber 62 is provided between the clutch drum 50 and the clutch piston 52. A centrifugal cancel chamber 63 is provided between the spring retainer 55 and the clutch piston 52 to eliminate the influence of centrifugal hydraulic pressure.

  A clutch return spring 54 is installed in the centrifugal cancel chamber 63 so as to be displaceable in the x-axis direction. The x-axis positive direction end of the clutch return spring 54 is fixed to the spring retainer 55, and the x-axis negative direction end of the clutch return spring 54 is fixed to the clutch piston 52. The clutch piston 52 is provided so as to be movable in the x-axis direction. The spring retainer 55 is fixed by a snap ring 56 so as not to move in the positive x-axis direction.

  The hydraulic oil is supplied to and discharged from the forward clutch piston chamber 62 via the forward clutch input port 61. When hydraulic oil is supplied from the forward clutch input port 61, the force of the product of the hydraulic pressure in the forward clutch piston chamber 62 (hereinafter referred to as clutch engagement hydraulic pressure Pc) and the pressure receiving area of the clutch piston 52 is applied to the clutch piston 52. Acts in the positive x-axis direction. For this reason, the clutch piston 52 strokes in the positive x-axis direction.

  On the other hand, when the clutch piston 52 strokes in the x-axis positive direction, the clutch return spring 54 is compressed, and an elastic force that is the product of the stroke amount x of the clutch return spring 54 and the elastic coefficient is applied to the clutch piston 52. Acting in the negative x-axis direction.

  FIG. 4 shows the relationship between the stroke amount x of the clutch return spring 54 and the elastic force of the clutch return spring 54, that is, the spring load F.

  The clutch piston 52 strokes to a position where the urging force by Pc and the spring load F of the clutch return spring 54 are balanced. When hydraulic oil is not supplied to the forward clutch piston chamber 62 and Pc is zero, the clutch piston 52 is urged in the negative direction of the x-axis by the clutch return spring 54 and pressed against the clutch drum 50. The stroke amount x of the piston 52 is zero. The spring load F of the clutch return spring 54 at this time is an initial set load F0.

  A predetermined amount of clearance is provided between the clutch piston 52 and the plurality of friction plates 50a and 51a, and the clutch piston 52 is kept in contact with each other until the input and output friction plates 50a and 51a are all in contact with each other. It is necessary to stroke a predetermined amount in the positive x-axis direction. Let this stroke amount be x1.

  When x is zero (the clearance is maximum) to x1 (the clearance is zero), no friction force is generated between the plurality of friction plates 50a and 51a, and the forward clutch 2d does not have a torque capacity. That is, the forward clutch 2d is in a non-engaged state.

  When the clutch piston 52 moves in the x-axis positive direction by x1 and stops when the urging force by Pc balances with the spring load F of the clutch return spring 54, the magnitude of Pc is Pc1. The spring load F of the clutch return spring 54 at this time is F1.

  When Pc is larger than Pc1 in the state where x is x1, the disc spring 53 starts to be compressed, a frictional force is generated between the plurality of friction plates 50a and 51a, and the forward clutch 2d has a torque capacity Tc. become. That is, the engaged state of the forward clutch 2d starts.

(Outline of hydraulic circuit)
FIG. 5 shows a part of the hydraulic circuit in the hydraulic control valve unit 8. A pressure regulator valve (P.REG.V) 110 that regulates the line pressure PL is connected to the discharge port of the oil pump 7 via an oil passage 101. The first hydraulic pressure (PL) regulated between the oil pump 7 and P.REG.V110 is supplied to oil passages 102 and 103 connected to the oil passage 101.

  The oil passage 102 is connected to an oil passage 70 that communicates the primary clamp chamber 30d and the secondary clamp chamber 31d. PL regulated by P.REG.V110 is always supplied to the primary clamp chamber 30d and the secondary clamp chamber 31d via the oil passage 70.

  An oil passage 104 and oil passages 106 to 108 are connected to the oil passage 103. An oil passage 111 described later is connected to the oil passage 104 via an orifice 105. A secondary valve (SEC.V) 140 that supplies the hydraulic pressure of the secondary pulley cylinder chamber 31c is connected to the oil passage 106. A shift control valve 170 that supplies the hydraulic pressure of the primary pulley cylinder chamber 30c is connected to the oil passage 107.

  An oil passage 171 for supplying primary pulley hydraulic pressure to the primary pulley cylinder chamber 30c is connected to the shift control valve 170. Further, a mechanism (gear ratio sensor 30i) indicating the groove width of the primary pulley 30 and the step motor 10 are connected to the shift control valve 170 via a link 172, and these are the drive amount of the step motor 10, that is, the number of rotation steps. This constitutes a mechanical feedback mechanism for feedback control of the gear ratio.

  Connected downstream of P.REG.V110 is a clutch regulator valve (CL.REG.V) 120 that regulates a second hydraulic pressure lower than PL (for example, a fastening hydraulic pressure for forward clutch 2d) via oil passage 111. Has been. The second hydraulic pressure regulated by CL.REG.V120 is supplied to the select switching valve (SELECT.SW.V) 182 and the select control valve (SELECT.CONT.V) 183 via the oil passage 112, The oil is supplied to a secondary control valve (SEC.CONT.V) 150, which is a proportional control valve, through an oil passage 113.

  A switching valve 190 is connected to the oil passage 104 via an oil passage 109. The switching valve 190 is connected to the oil passage 112 via the oil passage 191 and switches the communication state between the oil passage 103 that supplies pulley oil pressure and the oil passage 112 that supplies forward clutch pressure.

  A pilot valve (PILOT.V) 130 is connected to the oil passage 108. PILOT.V130 supplies a pilot pressure that is a source pressure of the signal pressure. The pilot pressure is passed through the oil passage 131 through the secondary pressure solenoid valve (SEC.SOL.V) 160, lockup solenoid valve (L / U.SOL.V) 180, and select switching solenoid valve (SELECT.SW.SOL. V) supplied to 181.

  The signal pressure regulated by SEC.SOL.V160 is supplied as the back pressure of SEC.CONT.V150 via the oil passage 161. The third hydraulic pressure adjusted in SEC.CONT.V150 (the hydraulic pressure obtained by adjusting the second hydraulic pressure) is supplied as the back pressure of SEC.V140 through the oil passage 151. The hydraulic pressure adjusted with PL as the original pressure in SEC.V140 is supplied to the secondary pulley cylinder chamber 31c.

  The output pressure of SELECT.SW.SOL.V 181 is supplied to a select switching valve (SELECT.SW.V) 182 via an oil passage 185, and the operation of SELECT.SW.V 182 is controlled as a signal pressure. The output pressure of L / U.SOL.V 180 is supplied to SELECT.SW.V 182 via an oil passage 184.

  When SELECT SW SOL V 181 is ON, the signal pressure (output pressure) of SELECT SW SOL V 181 is input to SELECT SW V 182. Then, SELECT.SW.V 182 cuts off the oil passage 112 connected to CL.REG.V120 and the oil passage 40 connected to the manual valve 21, while the oil passage connected to SELECT.CONT.V183. 115 communicates with oil passage 40. At the same time, the oil passage 184 connected to L / U.SOL.V 180 and the oil passage 186 connected to SELECT.CONT.V183 are communicated.

  Therefore, at this time, all of the hydraulic oil (second hydraulic pressure) from the oil passage 112 is supplied to SELECT.CONT.V183, and in accordance with the signal pressure from L / U.SOL.V 180 in SELECT.CONT.V183. It is regulated. The clutch engagement hydraulic pressure Pc adjusted to a hydraulic pressure (shelf pressure) lower than the second hydraulic pressure is supplied to the manual valve 21 via the oil passage 115, SELECT.SW.V 182 and the oil passage 40.

  When SELECT SW SOL V 181 is OFF, the signal (output pressure) of SELECT SW SOL V 181 is zero and no signal pressure is supplied to SELECT SW V 182. Then, SELECT.SW.V 182 connects the oil passage 112 and the oil passage 40 while blocking the oil passage 115 and the oil passage 40. At the same time, the oil passage 184 connected to the L / U.SOL.V 180 and the oil passage 187 connected to a lockup control valve (not shown) are communicated, while the oil passage 184 and the oil passage 186 are blocked.

  Therefore, at this time, all the hydraulic oil (second hydraulic pressure) from the oil passage 112 is supplied to the manual valve 21 through the oil passage 40. On the other hand, the signal pressure from L / U.SOL.V 180 is supplied to a lockup control valve (not shown) and acts as the signal pressure of this lockup control valve.

  The oil passage 40 is provided with a hydraulic pressure sensor 40a.

(Configuration of hydraulic control device)
The hydraulic control apparatus of the present invention is a mechanical hydraulic control means comprising SELECT.SW.V 182 and SELECT.CONT.V183, a manual valve 21, a pressure holding valve 22, and check valves (check valves) 23, 26 and 28. And an electronic hydraulic control means comprising a CVT control unit 9, L / U.SOL.V 180, and SELECT.SW.SOL.V 181.

(Electronic hydraulic control means)
The CVT control unit 9 performs idle stop control for stopping the engine when a predetermined condition is satisfied in order to improve fuel consumption. The CVT control unit 9 detects that the vehicle speed is extremely low and that the engine is idling, and starts and ends idle stop control using signals from various sensors such as brake switch and oil temperature sensor 5c. Judging. For example, if the vehicle speed is zero, the idle stop switch is ON, the brake switch is ON, the oil temperature T is within a predetermined range, the steering angle is zero, the engine is stopped. If the brake switch is turned off, the starter is driven to restart the engine.

  The CVT control unit 9 outputs commands to L / U.SOL.V 180 and SELECT.SW.SOL.V 181 and restarts the engine using SELECT.SW.V 182 and SELECT.CONT.V183. Shelf pressure control is performed to gradually increase the engagement hydraulic pressure Pc supplied to the forward clutch 2d.

  When the engine restarts, the oil pump 7 starts to operate, and when supplying hydraulic pressure to the forward clutch 2d, it is necessary to supply clamp pressure at the same time. If the hydraulic pressure supply to the forward clutch 2d is too smooth, there is a concern about securing the clamp pressure when the engine is restarted. Therefore, the CVT control unit 9 controls the SELECT.CONT.V183 with the signal pressure of the L / U.SOL.V 180 after turning on the SELECT.SW.V 182. As a result, the hydraulic oil (second hydraulic pressure) from the oil passages 112 and 114 is adjusted in SELECT.CONT.V183, and the hydraulic pressure (shelf pressure) adjusted lower than the second hydraulic pressure is changed to the oil passage 115, SELECT The forward clutch 2d is supplied through .SW.V 182 and the oil passage 40.

  By executing the optimum shelf pressure control of the forward clutch 2d in this way, it is possible to avoid belt slipping due to a decrease in pump discharge pressure at the time of engine restart, and smooth start after engine restart as will be described later. Is possible.

(Hydraulic clutch hydraulic control circuit)
FIG. 6 shows a hydraulic control circuit 20 that controls a part of the mechanical hydraulic control means of the hydraulic control apparatus of the present invention, that is, the fastening hydraulic pressure Pc supplied from the manual valve 21 to the forward clutch 2d. The discharge pressure of the oil pump 7 is regulated by the electronic hydraulic control means, and the regulated hydraulic pressure is supplied to the manual valve 21 via the oil passage 40.

  The manual valve 21 is connected to the forward clutch 2d and the reverse brake 2e. The manual valve 21 and the forward clutch 2d are connected by an oil passage 42 that passes through the pressure holding valve 22 and oil passages 43 and 44 that do not pass through the pressure holding valve 22.

  The oil passage 40 from SELECT.SW.V182 is connected to the suction port 21a of the manual valve 21. The manual valve 21 has a D range port 21b, an R range port 21c, and drain ports 21d and 21e. The D range port 21b is connected to the forward clutch 2d via the oil passage 41 and the oil passages 42 and 43. The R range port 21c is connected to the reverse brake 2e via oil passages 42 to 49.

  The manual valve 21 has a spool 210 that is housed in the valve body of the hydraulic control valve 8. The spool 210 has a first land portion 211 formed on the x-axis positive direction side and a second land portion 212 formed on the x-axis negative direction side. The first land portion 211 and the second land portion 212 are connected via a small-diameter connecting portion 213, and a communication chamber 214 is formed between the connecting portion 213 and the valve body.

  The D range port 21 b of the manual valve 21 is connected to the oil passage 41, and the oil passage 41 branches into an oil passage 42 and an oil passage 43. Both the oil passage 42 and the oil passage 43 are connected to the forward clutch input port 61 (see FIG. 3) of the forward clutch 2d. A pressure holding valve 22 is provided on the oil passage 42. On the oil passage 43, an orifice 24 and a check valve 23 are provided in order from the manual valve 21 side toward the forward clutch 2d side. The check valve 23 allows only oil to flow from the manual valve 21 toward the forward clutch 2d, and prohibits oil from flowing from the forward clutch 2d toward the manual valve 21.

  The port 21d is connected to the oil passage 44, and the oil passage 44 is connected to the forward clutch input port 61 of the forward clutch 2d. An orifice 25 is provided on the oil passage 44.

  The R range port 21 c is connected to the oil passage 45, and the oil passage 45 branches into an oil passage 46 and an oil passage 49. The oil passage 46 is branched into an oil passage 46 a and an oil passage 48, and the oil passage 49 is branched into an oil passage 46 a and an oil passage 47. In other words, the oil passage 46 and the oil passage 49 are connected to each other via the oil passage 46a. Both the oil passage 47 and the oil passage 48 are connected to the reverse clutch 2e.

  A check valve 26 is provided on the oil passage 46. The check valve 26 allows only oil to flow from the manual valve 21 toward the reverse brake 2e, and prohibits oil from flowing from the reverse brake 2e to the manual valve 21. An orifice 27 is provided on the oil passage 47. A check valve 28 is provided on the oil passage 48. The check valve 28 only allows oil to flow from the manual valve 21 to the reverse brake 2e, and prohibits oil from flowing from the reverse brake 2e to the manual valve 21. An orifice 29 is provided on the oil passage 49.

(Manual valve)
The manual valve 21 is connected to a shift lever (not shown) via a link (not shown), and supplies hydraulic oil to the forward clutch 2d or hydraulic oil to the reverse brake 2e according to the operation of the shift lever. Switch what to do. For the sake of explanation, hereinafter, the x axis is set in the axial direction of the manual valve 21, and the D range port 21b side is defined as the negative direction with respect to the R range port 21c.

  When the shift lever is operated to the D range position, the spool 210 of the manual valve 21 moves in the positive direction of the x-axis, the first land portion 211 connects the D range port 21b and the suction port 21a, and the drain port 21d is close. At the same time, the second land portion 212 blocks the R range port 21c and the suction port 21a and allows the R range port 21c and the drain port 21e to communicate with each other.

  When the shift lever 21 is operated to the N range position, the spool 210 moves in the negative x-axis direction from the D range position, the first land portion 211 shuts off the D range port 21b and the suction port 21a, and the drain port Open 21d. At the same time, the second land portion 212 blocks the R range port 21c and the suction port 21a and keeps the R range port 21c and the drain port 21e in communication (see FIG. 11).

  When the shift lever 21 is operated to the R range position, the spool 210 moves in the x-axis negative direction from the N range position, the first land portion 211 shuts off the D range port 21b and the suction port 21a, and the drain port Keep 21d open. At the same time, the second land portion 212 causes the R range port 21c and the suction port 21a to communicate with each other and blocks the R range port 21c and the drain port 21e (see FIG. 12).

  When the shift lever 21 is operated to the P range position, the spool 210 moves in the negative x-axis direction from the R range position, the first land portion 211 shuts off the D range port 21b and the suction port 21a, and the drain port Keep 21d open. At the same time, the first land portion 211 blocks the R range port 21c and the suction port 21a, and the second land portion 212 communicates the R range port 21c and the drain port 21e (see FIG. 13).

(Pressure holding valve)
The pressure holding valve 22 includes a check ball 22a and a spring 22b. Hereinafter, for explanation, the y-axis is set in the expansion / contraction direction of the spring 22b, and the forward clutch 2d side is defined as the positive direction. The spring 22b urges the check ball 22a in the positive y-axis direction with a predetermined elastic force. The pressure holding valve 22 allows only the flow of oil from the forward clutch 2d toward the manual valve 21, and prohibits the flow of oil from the manual valve 21 toward the forward clutch 2d. When the load due to the engagement hydraulic pressure Pc of the forward clutch 2d acting on the check ball 22a becomes greater than or equal to the elastic force of the spring 22b, the oil flow from the forward clutch 2d toward the switching valve 23 is permitted.

[Operation of Example 1]
(Hydraulic retention during idle stop in D range)
FIG. 6 shows the flow of hydraulic oil in the hydraulic control circuit 20 when the vehicle is idled in the D range after running in the D range with a dotted arrow.

  In the D range, the D range port 21b and the suction port 21a communicate with each other, and the drain port 21d is closed. Since the engine is not operated, the oil pump 7 does not operate, and hydraulic oil is not supplied to the forward clutch 2d via the oil passage 40 and the oil passage 41. On the other hand, the hydraulic oil supplied to the forward clutch 2d is not drained through the oil passage 44 because the drain port 21d is closed. Further, the hydraulic oil supplied to the forward clutch 2 d is not drained through the oil passage 43 due to the action of the check valve 23.

  Here, due to the action of the pressure-holding valve 22, the flow of the hydraulic oil from the forward clutch 2d side via the oil passage 42 is allowed to be limited. Therefore, the hydraulic oil that has been supplied to the forward clutch piston chamber 62 is partially drained via the pressure holding valve 22.

  That is, since the oil pressure in the oil passage 40 is zero, the oil pressure in the D range port 21b and the oil passage 41 communicating with the supply port 21a of the manual valve 21 is also zero. Therefore, in the pressure retaining valve 22, the hydraulic pressure Pc on the forward clutch 2d side that biases the check ball 22a in the negative y-axis direction and the elastic force of the spring 22b that biases the check ball 22a in the positive y-axis direction are balanced. Until the pressure is reached, the pressure holding valve 22 is opened.

  Thereafter, hydraulic oil is drained from the forward clutch piston chamber 62 toward the manual valve 21 via the pressure holding valve 22. As a result of the draining of the hydraulic oil, when the Pc of the forward clutch piston chamber 62 becomes a value that balances the elastic force of the spring 22b, the pressure retaining valve 22 is closed. Thereby, Pc is held at a value that balances the elastic force (spring load f) of the spring 22b. That is, the pressure keeping valve 22 keeps Pc at a predetermined constant pressure as follows when the hydraulic pressure Pc of the forward clutch piston chamber 62 is higher than the hydraulic pressure on the D range port 21b side.

  That is, the spring load f of the spring 22b is set to be a value f * (for example, f1) larger than f0. f0 is the magnitude of the spring load (initial set load) of the spring 22b that balances with Pc (= 0) when the spring load of the clutch return spring 54 is F0 (initial set load), that is, when Pc is zero. It is. f1 is the magnitude of the spring load of the spring 22b that balances with Pc (= Pc1) when the spring load of the clutch return spring 54 is F1, that is, when Pc is Pc1 (see FIG. 4). By setting the spring load f of the spring 22b to a value f * in the above range, Pc is set to a value P * (for example, Pc1) greater than zero.

  By setting Pc held at the time of idling stop to Pc *, the stroke amount x of the clutch piston 52 is also kept at a constant value x * in a range greater than 0 and less than or equal to x1. Therefore, the clutch clearance is reduced as a result of the stroke amount x of the clutch piston 52 being held at a constant value x * by the action of the pressure holding valve 22.

  In the D range position, since the drain port 21d is closed by the first land portion 211 of the spool 210 of the manual valve 21, the hydraulic oil supplied to the forward clutch 2d is not drained through the oil passage 44. . The forward clutch 2 d and the oil passages 42 to 44 form a closed circuit by the action of the pressure holding valve 22 and the check valve 23. As a result, the forward clutch piston chamber 62 itself has an accumulator function. Therefore, even if idling is stopped for a long time in the D range, the decrease in Pc * held in the forward clutch 2d is extremely small.

  On the other hand, when the R range, N range, or P range is selected during the idle stop, the drain port 21d is opened, so that the hydraulic oil held in the forward clutch 2d is drained through the oil passage 44. That is, the operation of the pressure holding valve 22 is lost, and Pc becomes zero.

(Hydraulic supply when the D range restarts after idle stop)
When the engine restarts in the D range after the idle stop, the discharge hydraulic pressure of the oil pump 7 starts to rise when the engine is restarted and the engine speed reaches a predetermined Ne or higher. When the hydraulic pressure supplied from SELECT.SW.V182 to the oil passage 40 becomes Pc * or more, the check valve 23 is opened, and the hydraulic pressure in the oil passage 40 is supplied to the forward clutch 2d via the oil passage 43.

  Thus, when the check valve 23 is opened, Pc is substantially kept at a predetermined value Pc * of zero or more by the action of the pressure holding valve 22, and the stroke amount x of the clutch piston 52 of the forward clutch 2d is a predetermined value of zero or more. Held in the value x *. When x * is x1, the torque capacity Tc of the forward clutch 2d is zero or more, and there is no need to stroke the clutch piston 52 any further.

  Further, when x * is less than x1, the increment (Pc1-Pc) of Pc required to stroke the clutch piston 52 further and start the engaged state of the forward clutch 2d can be reduced. Therefore, the torque capacity Tc of the forward clutch 2d is generated with almost no time delay when the vehicle restarts after the idle stop.

  As described above, the mechanical hydraulic control means (hydraulic control circuit 20) of the present invention maintains the Pc at the predetermined value Pc * that balances the spring force of the return spring 54 during the idle stop, so that the engine after the idle stop is achieved. At the time of restart, the torque capacity Tc of the forward clutch 2d is already generated and the engaged state is started. Alternatively, the time required to raise Pc to Pc1 when the engine is restarted after the idle stop is shortened. In other words, the forward clutch 2d is stroked (precharged) in advance.

  Further, as described above, the electronic hydraulic control means of the hydraulic control apparatus according to the present invention performs shelf pressure control for gradually increasing Pc and relieving the fastening shock after the engine is restarted. Hereinafter, specific contents of the shelf pressure control will be described.

  When the engine is restarted, the engine is cranked by the starter motor and at the same time SELECT.SW.SOL.V 181 is turned ON. Further, a shelf pressure control end hydraulic pressure Pc1 ′, a shelf pressure control end timer T0, and a quick filling end hydraulic pressure Pc01 are set from a predetermined MAP according to the throttle opening.

  Immediately after the engine restart, since the hydraulic pressure from the oil pump 7 is not sufficiently obtained, the switching valve 190 is turned ON. The oil pressure from the oil pump 7 is as follows: oil passage 101 → oil passage 103 → oil passage 104 → oil passage 109 → switching valve 190 → oil passage 191 → oil passage 112 → oil passage 114 → SELECT.CONT.V183 → oil Road 115 → SELECT.SW.V 182 → Oil path 40 → Supplied to manual valve 21 and supplied to forward clutch 2d.

  When the oil pressure in the oil passage 40 reaches Pc *, the command oil pressure is output to the L / U.SOL.V 180 and the ramp control of the L / U.SOL.V 180 is started. As a result, the engagement hydraulic pressure Pc supplied to the forward clutch 2d gradually increases (shelf pressure control starts). Moreover, the count of the shelf pressure control end timer T0 is started.

  When the oil pressure in the oil passage 40 reaches the rapid filling end oil pressure Pc01 (> Pc *), the switching valve 190 is turned OFF. At this time, the hydraulic pressure from the oil pump 7 is as follows: oil passage 101 → oil passage 111 → oil passage 112 → oil passage 114 → SELECT CONT.V183 → oil passage 115 → SELECT.SW.V 182 → oil passage 40 → manual valve 21 and supplied to the forward clutch 2d.

  When the shelf pressure control end timer T0 elapses, the lamp control of the L / U.SOL.V 180 is ended and the L / U.SOL.V 180 is turned off. That is, the output pressure of L / U.SOL.V 180 is set to zero.

  When L / U.SOL.V 180 is turned OFF, in SELECT.CONT.V183, the oil passage 114 and the oil passage 115 are completely in communication, and the manual valve 21 is connected to CL.REG.V120. The regulated hydraulic pressure (second hydraulic pressure) is directly supplied. Thereby, Pc rises to the maximum value Pcmax.

  In this state, SELECT.SW.V 182 is turned OFF. Then, the oil passage 112 and the oil passage 40 are in a communication state, and the shelf pressure control by the L / U.SOL.V 180 is shifted to the normal control by the CL.REG.V120. The oil passage 184 from the L / U.SOL.V 180 is in communication with a lock-up control valve (not shown), and the output pressure of the L / U.SOL.V 180 is used as the signal pressure for lock-up control. Function.

(Time chart)
FIG. 7 is a time chart showing a process in which the engagement hydraulic pressure Pc is supplied to the forward clutch 2d when the engine is restarted after the idle stop, the torque capacity Tc of the forward clutch 2d is generated, and the longitudinal G of the vehicle is generated. Hereinafter, the case where P * is less than Pc1 is shown, but the same applies to the case where P * is Pc1 or more.

  For comparison, graphs of Conventional Example 1 and Conventional Example 2 are also shown in addition to the present invention. Conventional example 1 is a method in which means for controlling the engagement hydraulic pressure of the forward clutch during idle stop is not provided. Conventional Example 2 is a system in which a hydraulic pressure supply means is provided separately from the oil pump driven by the engine, and the forward clutch is maintained in the engaged state by the hydraulic pressure supplied by the hydraulic pressure supply means during idle stop.

(Time chart of engine speed)
At t1, the engine is restarted and the engine speed Ne starts to increase. After overshooting, Ne stabilizes at a constant speed.

(Time chart of the present invention)
At t1, the oil pump 7 starts operating, but Pc is kept at Pc * by the action of the pressure holding valve 22. When Ne becomes a predetermined value or more, the oil pump 7 can supply a hydraulic pressure equal to or higher than Pc * to the oil passage 40. Therefore, at t2 when Ne becomes the predetermined value, Pc starts to rise from Pc *. Here, the shelf pressure control of Pc is started. When Pc rises to Pc1 at t3, the forward clutch 2d is engaged. That is, at t3, the torque capacity Tc of the forward clutch 2d starts to increase from zero. At t6 after the shelf pressure control end timer T0 elapses from t2, the shelf pressure control is ended and Pc is increased to the maximum value Pcmax.

  By the action of the pressure holding valve 22 during idling stop, Pc is maintained at a predetermined value Pc * less than Pc1 before t2, and the stroke amount x of the clutch piston 52 of the forward clutch 2d is set to a predetermined value x * less than x1. Is retained. In other words, the increment (Pc1-Pc) of Pc required to stroke the clutch piston 52 further and start the engaged state of the forward clutch 2d is reduced. Therefore, in the present invention, after the idle stop, the time from the engine restart time t1 to the time point t3 when the torque capacity Tc of the forward clutch 2d is generated is short.

(Time chart of Conventional Example 1)
In Conventional Example 1, the engagement hydraulic pressure Pc of the forward clutch is zero during idle stop. After t1 when the engine is restarted, Pc starts to increase from zero by the operation of the oil pump. However, it takes time for the clutch piston of the forward clutch to stroke in order to reduce the clutch clearance that has been maintained to the maximum, and Pc is kept low during this time. For this reason, at t4, which is later than t3, Pc becomes Pc1, and the engaged state of the forward clutch 2d starts. That is, at t4, the torque capacity Tc of the forward clutch starts to increase from zero.

  From the above, in the hydraulic control device of the present invention provided with the pressure holding valve 22, the time from the restart of the engine to the time when the torque capacity of the forward clutch 2d is generated at the time of restart after the idle stop is achieved. Short and good response to relapse.

(Time chart of Conventional Example 2)
In Conventional Example 2, the engagement hydraulic pressure Pc of the forward clutch is maintained at the maximum value Pcmax during idle stop. Therefore, the torque capacity Tc of the forward clutch is the maximum value Tcmax at the time t1 when the engine is restarted, and the time from when the engine is restarted until the time when the torque capacity of the forward clutch 2d is generated is short, and the restart response is good. Is the same as in the present invention.

  However, since Tc is continuously maintained at the maximum value Tcmax before and after t1 when the engine is restarted, the sudden increase in engine torque accompanying Ne overshoot is directly transmitted to the output shaft of the automatic transmission, and the front and rear G increases rapidly. . Therefore, a sudden jump-out feeling of the vehicle occurs.

  On the other hand, in the hydraulic control device for the forward clutch 2d of the present invention, Pc is controlled not to increase rapidly even after t2 by the shelf pressure control. Pc gradually rises to Pc1 ′ (<Pcmax) and then reaches the maximum pressure Pcmax after completion of engagement of the forward clutch 2d, that is, after time t5 when Tc becomes Tcmax. Thus, the rising curve of Tc is controlled to be smooth, and the forward clutch 2d does not suddenly have a large torque capacity Tc. Therefore, regardless of Ne's overshoot, the change in front and rear G is gradual. Therefore, the sudden feeling of jumping out of the vehicle as in the conventional example 2 does not occur.

  8 to 10 show the relationship between the engagement hydraulic pressure Pc of the forward clutch 2d and the clutch torque capacity Tc, that is, the torque that can be transmitted by the forward clutch 2d. As shown in each figure, an upper limit of the fastening hydraulic pressure Pc * held by the pressure holding valve 22 is determined, and an area of Pc * is set. Hereinafter, each setting area of Pc * will be described together with the function and effect when the area is set to that area.

(Holding hydraulic pressure setting capable of creep travel)
FIG. 8 shows a region of Pc * when Tc (= Tc *) of the forward clutch 2d generated by Pc * is set to be equal to or less than the torque transmitted during creep travel. Pc1 is a Pc that makes the clutch clearance substantially zero against the spring load F of the clutch return spring 54 as described above and generates the clutch torque capacity Tc of the forward clutch 2d. Tc is zero in a region where Pc is from zero to less than Pc1, and is proportional to Pc in a region where Pc1 or higher.

  Pc * is determined to be not less than Pc1 and not more than Pc2. Pc2 is a Pc that generates a torque capacity Tc2 that can maintain normal creep start.

  By setting the lower limit of Pc * to Pc1, there is no need to close the piston stroke of the forward clutch 2d at the time of re-starting after idling stop, and a predetermined control hydraulic pressure can be quickly created by the residual pressure Pc *. There is no reduction in relapse response. Note that the lower limit of Pc * is not limited to Pc1, and may be Pc that can reduce the clutch clearance of the forward clutch 2d.

  On the other hand, when the upper limit of Pc * is set to Pc2, when excessive torque is input to the forward clutch 2d due to the engine speed overshoot after the engine complete explosion at the time of re-start after idle stop, Since the forward clutch 2d cannot transmit a torque larger than Tc2, it is possible to prevent sudden start. In other words, when the engine is restarted at zero accelerator opening after restarting the engine, smooth creep start is performed regardless of how the engine speed increases.

(Holding pressure setting that prevents belt slippage)
FIG. 9 shows a region of Pc * when the clutch torque capacity Tc of the forward clutch 2d is set to be equal to or less than the pulley torque capacity Tp, that is, the torque that can be transmitted by the primary pulley 30. Specifically, Tc (= Tc *) generated by Pc * is equal to or lower than Tp (= Tp *) when the hydraulic pressure supplied to the forward clutch 2d after engine restart is equal to Pc *. Set the Pc * area.

  When the oil pump 7 is not operating and the hydraulic pressure supplied to the primary pulley cylinder chamber 30c and the secondary pulley cylinder chamber 31c is zero, Pc is zero and Tp is Tp0. Tp0 is a torque that can be transmitted by the primary pulley 30 when Pc is zero.

  When the hydraulic pressure supplied to the secondary pulley 31 is zero, the groove width of the secondary pulley 31 is narrowed by the spring load of the spring 31j provided in the secondary pulley cylinder chamber 31c, and the pitch radius on the secondary pulley 31 side is large. Become. At the same time, since the length of the belt 15 is constant, the groove width of the primary pulley 30 is widened, and the pitch radius on the primary pulley 30 side becomes a small diameter. Therefore, the pulley ratio becomes the low side, and at this time, a frictional force is generated between the belt 15 and the primary pulley 30, and a predetermined torque Tp0 can be transmitted.

  As the hydraulic pressure supply capacity of the oil pump 7 increases and Pc increases from zero, the hydraulic pressure supplied to the primary pulley cylinder chamber 30c and the secondary pulley cylinder chamber 31c increases correspondingly. For this reason, the torque Tp that can be transmitted by the primary pulley 30 increases in proportion to Pc when Pc becomes zero or more. On the other hand, as described above, Tc increases when Pc becomes equal to or higher than Pc1. Tc has a larger rate of increase with respect to Pc than Tp. For this reason, Tc matches Tp when Pc becomes Pc3.

  Therefore, as shown in FIG. 9, in the region where Pc is greater than or equal to zero and less than or equal to Pc3, Tc is equal to or less than Tp. In the region where Pc is larger than Pc3, Tc is larger than Tp.

  Pc * is determined to be not less than Pc1 and not more than Pc3. Pc3 is Pc in which the pulley torque capacity Tp and the clutch torque capacity Tc match.

  By setting the upper limit of Pc * to Pc3, Tc * generated by Pc * is equal to or less than Tp * when the hydraulic pressure supplied from the oil pump 7 to the forward clutch 2d becomes equal to Pc *. That is, the clutch torque capacity Tc (= Tc *) of the forward clutch 2d held by the pressure holding valve 22 does not exceed the torque Tp that can be transmitted by the primary pulley 30.

  For this reason, when the vehicle restarts after the idle stop, a torque equal to or less than Tp is input from the forward clutch 2d to the primary pulley 30 via the CVT input shaft 14. Therefore, in the primary pulley 30, the belt slip at the time of engine restart after an idle stop is prevented. Since the secondary pulley 31 at the time of starting is on the large diameter side, no belt slip occurs in the secondary pulley 31 as well.

(Holding pressure setting that prevents belt slippage when pulley pressure is zero)
FIG. 10 shows that the primary pulley 30 can transmit when Tc (= Tc *) of the forward clutch 2d generated by Pc * is zero in the hydraulic pressure supplied to the primary pulley 30 and the secondary pulley 31 (including the clamping chamber). This shows the Pc * area when the torque is set to be less than the torque.

  Pc * is determined to be not less than Pc1 and not more than Pc4. Pc4 is Pc that generates a torque Tp0 that can be transmitted by the primary pulley 30 when the hydraulic pressure supplied to the primary pulley 30 and the secondary pulley 31 is zero.

  By setting the upper limit of Pc * to Pc4, Tc * generated by Pc * is equal to or lower than Tp0 held when the pulley hydraulic pressure is zero. That is, the clutch torque capacity Tc (= Tc *) of the forward clutch 2d held by the pressure holding valve 22 does not exceed the torque Tp0 that can be transmitted by the primary pulley 30 when the pulley hydraulic pressure is zero. Since the secondary pulley 31 at the time of starting is on the large diameter side, no belt slip occurs in the secondary pulley 31 as well.

  Therefore, even when the vehicle is stopped for a long time and the pulley hydraulic pressure is released, the belt slip is reliably prevented when the engine is restarted after the idle stop.

(Hydraulic supply in N range after idling stop)
FIG. 11 shows the flow of hydraulic oil in the hydraulic control circuit 20 when the engine is operating at the N range position after the idle stop by a dotted line arrow.

  In the N range, the first land portion 211 blocks the D range port 21b and the suction port 21a and opens the drain port 21d. Therefore, hydraulic fluid is not supplied from the D range port 21b to the forward clutch 2d. The hydraulic fluid in the forward clutch piston chamber 62 is drained via the oil passage 44 and the drain port 21d, and Pc * held in the forward clutch 2d becomes zero.

  At the same time, in the N range, the second land portion 212 blocks the R range port 21c and the suction port 21a and allows the R range port 21c and the drain port 21e to communicate with each other. Therefore, hydraulic fluid is not supplied from the R range port 21c to the reverse brake 2e. Further, the hydraulic oil is drained from the reverse brake 2e via the oil passages 48, 46a, 49, 45, the R range port 21c and the drain port 21e, and the engagement hydraulic pressure of the reverse brake 2e becomes zero.

  Therefore, at normal time when the engine is not idling (when the engine is operating), at the N range position, Pc * is zero, and the reverse brake 2e is not engaged, so vehicle start (creep, etc.) occurs in the N range. This situation is prevented.

(Hydraulic supply in R range after idle stop)
FIG. 12 shows the flow of hydraulic oil in the hydraulic control circuit 20 when the engine is operating at the R range position after the idle stop by a dotted line arrow.

  In the R range, the first land portion 211 blocks the D range port 21b and the suction port 21a and keeps the drain port 21d open. Therefore, hydraulic fluid is not supplied from the D range port 21b to the forward clutch 2d. The hydraulic fluid in the forward clutch piston chamber 62 is drained via the oil passage 44 and the drain port 21d, and Pc * held in the forward clutch 2d becomes zero.

  At the same time, in the R range, the second land portion 212 allows the R range port 21c and the suction port 21a to communicate with each other and blocks the R range port 21c and the drain port 21e. Therefore, the fastening hydraulic pressure is supplied from the R range port 21c to the reverse brake 2e via the oil passages 45, 46, 46a, 47.

  Therefore, at the normal time when the engine is not idling (when the engine is operating), at the R range position, the reverse brake 2e is engaged, while Pc * is zero, so both the forward clutch 2d and the reverse brake 2e are engaged. Interlock is prevented.

(Hydraulic supply in P range after idle stop)
FIG. 13 shows the flow of the hydraulic oil in the hydraulic control circuit 20 when the engine is operating at the P range position after the idle stop by a dotted line arrow.

  In the P range, the first land portion 211 blocks the D range port 21b and the suction port 21a and keeps the drain port 21d open. Therefore, hydraulic fluid is not supplied from the D range port 21b to the forward clutch 2d. The hydraulic fluid in the forward clutch piston chamber 62 is drained via the oil passage 44 and the drain port 21d, and Pc * held in the forward clutch 2d becomes zero.

  At the same time, in the P range, the first land portion 211 blocks the R range port 21c and the suction port 21a, and the second land portion 212 allows the R range port 21c and the drain port 21e to communicate with each other. Therefore, hydraulic fluid is not supplied from the R range port 21c to the reverse brake 2e. Further, the hydraulic oil is drained from the reverse brake 2e via the oil passages 48, 46a, 49, 45, the R range port 21c and the drain port 21e, and the engagement hydraulic pressure of the reverse brake 2e becomes zero.

  Therefore, at normal time when the engine is not idling (when the engine is operating), at the P range position, Pc * is zero, and the reverse brake 2e is not engaged. A situation where the mechanism fails is prevented.

[Effect of Example 1]
The hydraulic control device for an automatic transmission according to the first embodiment has the effects listed below.

  (1) a clutch piston 52 that is moved by supply of hydraulic oil from an oil pump 7 driven by the engine, and a plurality of friction plates 50a and 51a on the input side and output side that are pressed against each other by the movement of the clutch piston 52; A clutch return spring 54 that secures a predetermined clearance between the clutch piston 52 and the plurality of friction plates 50a and 51a by an elastic force at the time of engagement, and is engaged when the D range is selected as the shift position. In a hydraulic control device for an automatic transmission that includes a forward clutch 2d and a CVT control unit 9 that performs idle stop control by stopping the engine when a predetermined condition is satisfied, hydraulic oil is discharged from the forward clutch 2d. An oil passage 42, an oil passage 43 for supplying hydraulic oil from the oil pump 7 to the forward clutch 2d, and a D range When a shift position (R, N, P range) other than the position is selected, an oil passage 44 for discharging the hydraulic oil from the forward clutch 2d is provided, and the oil pump 7 is on the oil passage 42 when the oil pump 7 is not in operation. A pressure holding valve 22 for holding the engagement hydraulic pressure Pc of the forward clutch 2d at Pc * is provided to permit the hydraulic oil to flow from the oil pump 7 to the forward clutch 2d on the oil passage 43, and from the forward clutch 2d to the oil pump. The check valve 23 for prohibiting the flow of hydraulic oil to the valve 7 is provided, and the load applied to the clutch piston 52 by the held hydraulic pressure Pc * is larger than the elastic force of the clutch return spring 54 when the clearance is maximum. It was decided.

  Pc immediately before the engine is restarted and the oil pump 7 starts to operate is maintained at a pressure equivalent to the spring force of the clutch return spring 54 (Pc *) by the pressure holding valve 22. Therefore, it is not necessary to close the forward clutch 2d when the engine is restarted after the idle stop, and the forward clutch 2d can be quickly engaged. Therefore, the re-start response is good when the engine is restarted after the idle stop. In addition, even if there is an overshoot of the engine speed Ne when the engine is restarted, only the torque determined by the clutch torque capacity Tc can be transmitted, so that the vehicle can be smoothly restarted and prevented from suddenly popping out during the restart. it can. In addition, when the shift position is in the R, N, and P ranges, the hydraulic oil supplied to the forward clutch 2d is drained through the drain oil passage 44, so that the interlock in the R range, the creep in the N range, Failure of the parking mechanism in the P range can be reliably prevented. Furthermore, an electric pump, an accumulator, or the like is not required as the Pc holding means, and an electrohydraulic device such as a solenoid valve is not required as the Pc discharging means. Therefore, it is possible to improve vehicle mountability and cost.

  (2) After starting the operation of the oil pump 7, electronic hydraulic control means (CVT control unit 9, L / U.SOL) for adjusting the fastening hydraulic pressure Pc supplied from the oil pump 7 to the forward clutch 2d gradually increases. .V 180 and SELECT.SW.SOL.V 181).

  Pc before the engine is restarted and the oil pump 7 starts to operate is maintained at a pressure equivalent to the spring force of the clutch return spring 54 (Pc *) by the pressure holding valve 22. After the operation of the oil pump 7 (specifically, after the oil pressure in the oil passage 40 reaches Pc *), the engagement hydraulic pressure Pc of the forward clutch 2d is gradually increased without any step by the electronic hydraulic control means. It is controlled to become. For this reason, even if there is an overshoot of the engine speed Ne when the engine is restarted, only the torque determined by the clutch torque capacity Tc can be transmitted, so that the vehicle can be smoothly restarted and the vehicle suddenly pops out when restarting. It has the effect that it can be prevented.

  (3) When the D range is selected as the shift position, the hydraulic oil from the oil pump 7 is supplied to the oil passage 41 (and the oil passage 43), and when the shift position other than the D range is selected, the oil is The manual valve 21 for discharging the hydraulic oil from the passage 44 is provided, and the manual valve 21 switches between opening and closing of the oil passage 41 and the oil passage 44 by the movement of the spool 210 interlocked with the operation of the shift lever.

  The opening / closing of the drain port 21d is switched according to the position of the spool 210 of the manual valve 21, and Pc * held by the pressure holding valve 22 can be made zero by opening the drain port 21d. In other words, the manual valve 21 itself has a function of a switching valve for switching between supply and discharge of Pc * and a function of a discharge valve. Therefore, it is not necessary to add a special valve configuration such as a switching valve or a discharge valve, which is advantageous in terms of layout and cost. It has the effect.

  (4) The torque capacity Tc (= Tc *) of the forward clutch 2d generated by Pc * is equal to or less than the torque Tc2 transmitted by the forward clutch 2d during creep travel.

  Since the upper limit of the set pressure of the pressure-holding valve 22 is set to a range that generates a torque capacity that allows smooth creep running, excessive restart due to Ne overshoot after complete engine explosion at restart after idle stop Even if torque is input, it has the effect that sudden start can be prevented.

  (5) The automatic transmission has a CVT that can be steplessly changed by changing the groove widths of the primary pulley 30 and the secondary pulley 31 by hydraulic pressure, and the torque capacity Tc (= Tc *) is less than the torque Tp * that the primary pulley 30 can transmit when the hydraulic pressure supplied from the oil pump 7 to the forward clutch 2d becomes equal to Pc *.

  Since the upper limit of the set pressure of the pressure holding valve 22 is set in a range where the clutch torque capacity Tc of the forward clutch 2d does not exceed the pulley torque capacity Tp, it is possible to reliably prevent belt slip immediately after engine restart after idling stop. Has the effect.

  (6) The torque capacity Tc (= Tc *) of the forward clutch 2d generated by Pc * is the torque capacity Tp0 that can be transmitted by the primary pulley 30 when the hydraulic pressure supplied to the primary pulley 30 and the secondary pulley 31 is zero. It was decided that

  The pressure retaining valve is within a range in which the clutch torque capacity Tc of the forward clutch 2d does not exceed the torque capacity Tp0 that can be transmitted by the primary pulley 30 due to the spring load of the spring 31j installed in the secondary pulley cylinder chamber 31c when the pulley hydraulic pressure is zero. An upper limit of 22 set pressures is set. Therefore, even when the vehicle is stopped for a long time and the pulley hydraulic pressure is released, the belt slip at the time of restarting the engine can be reliably prevented.

[Other embodiments]
The best mode for carrying out the present invention has been described based on the first embodiment. However, the specific configuration of the present invention is not limited to the first embodiment and does not depart from the gist of the present invention. Any changes in the design of the range are included in the present invention.

  For example, in the first embodiment, the hydraulic control device of the present invention is applied to an automatic transmission having a belt type continuously variable transmission, but the present invention is applied to a stepped automatic transmission having a planetary gear train. Also good.

  In the first embodiment, the configuration in which the present invention is applied only to the forward clutch 2d as the starting fastening element has been described. However, the present invention may be applied to the reverse brake 2e.

1 is a schematic cross-sectional view of an automatic transmission according to a first embodiment to which a hydraulic control device of the present invention is applied. 1 shows a control system of an automatic transmission according to a first embodiment. FIG. 3 is a cross-sectional view in the transmission input axis direction of the forward clutch of the first embodiment. FIG. 3 is a correlation diagram between a stroke amount of a clutch return spring and a spring load of the forward clutch of the first embodiment. FIG. 3 is a hydraulic circuit diagram in the hydraulic control valve unit according to the first embodiment. FIG. 3 is a hydraulic circuit diagram for controlling forward clutch engagement hydraulic pressure according to the first embodiment. 6 is a time chart of engine speed, forward clutch engagement hydraulic pressure, torque capacity, and front and rear G when the engine is restarted after idle stop. It is a figure which shows the relationship between the forward clutch fastening oil_pressure | hydraulic of Example 1, and a clutch torque capacity | capacitance (a holding oil pressure is set so that it may become below the torque at the time of creep). It is a figure which shows the relationship between the forward clutch fastening hydraulic pressure and clutch torque capacity | capacitance of Example 1 (a holding hydraulic pressure is set so that it may become below pulley torque). It is a figure which shows the relationship between the forward clutch fastening hydraulic pressure and clutch torque capacity | capacitance of Example 1 (a holding hydraulic pressure is set so that it may become below pulley torque at the time of pulley hydraulic pressure zero). FIG. 3 is a hydraulic circuit diagram for controlling forward clutch engagement hydraulic pressure in the first embodiment (after idling stop, N range). It is a hydraulic-circuit figure which controls the forward clutch fastening hydraulic pressure of Example 1 (after an idle stop, R range). FIG. 2 is a hydraulic circuit diagram for controlling forward clutch engagement hydraulic pressure in the first embodiment (P range after idle stop).

Explanation of symbols

1 Torque converter 2 Forward / reverse switching mechanism 2d Forward clutch 2e Reverse brake 3 CVT
4 drive gear 4a idler gear 4b final gear 4c differential gear 4d idler shaft 5b engine speed sensor 7 oil pump 8 hydraulic control valve unit 9 CVT control unit 20 hydraulic control circuit 21 manual valve 21a intake port 21b D range port 21c R range port 21d, 21e Drain port 22 Pressure holding valve 22a Check ball 22b Spring 23, 26, 28 Check valve 24, 25, 27, 29 Orifice 30 Primary pulley 30a Primary movable pulley 30b Primary fixed pulley 30c Primary pulley cylinder chamber 30d Primary clamp chamber 31 Secondary pulley 31a Secondary movable pulley 31b Secondary fixed pulley 31c Secondary pulley cylinder chamber 31d Secondary clan Chambers 40 to 49 Oil passage 40a Oil pressure sensor 50a Input side friction plate 51a Output side friction plate 52 Clutch piston 53 Belleville spring 54 Clutch return spring 55 Spring retainer 61 Forward clutch input port 62 Forward clutch piston chamber 110 Pressure regulator valve 120 Clutch regulator valve 130 Pilot valve 170 Shift control valve 180 Lock-up solenoid valve 181 Select switching solenoid valve 182 Select switching valve 183 Select control valve 190 Switching valve 210 Spool 211 First land portion 212 Second land portion

Claims (6)

A piston that moves by supplying hydraulic oil from an oil pump driven by an engine; a plurality of input and output friction plates that are pressed against each other by the movement of the piston; A return spring that secures a predetermined clearance with the friction plate, and a starting fastening element that is fastened when the starting position is selected as the shift position;
In a hydraulic control device for an automatic transmission comprising an idle stop control means for stopping an engine when a predetermined condition is satisfied,
A first oil passage for discharging hydraulic oil from the starting fastening element;
A second oil passage for supplying hydraulic oil from the oil pump to the starting fastening element;
A third oil passage for discharging hydraulic oil from the starting fastening element when a shift position other than the starting position is selected;
Provided on the first oil passage is a pressure-holding valve for holding the fastening hydraulic pressure of the starting fastening element when the oil pump is not operated,
Provided on the second oil passage is a check valve that permits the flow of hydraulic oil from the oil pump to the starting fastening element and prohibits the flow of hydraulic oil from the starting fastening element to the oil pump. ,
A hydraulic control apparatus for an automatic transmission, wherein a load applied to the piston by the held hydraulic pressure is greater than an elastic force of the return spring when the clearance is maximum.   2. The hydraulic control unit according to claim 1, further comprising: a hydraulic pressure control unit that adjusts the fastening hydraulic pressure supplied from the oil pump to the starting fastening element to gradually increase after the oil pump starts operating. 3. Hydraulic control device for automatic transmission. When the start position is selected as the shift position, the hydraulic oil from the oil pump is supplied to the second oil passage. When the shift position other than the start position is selected, the hydraulic oil is supplied from the third oil passage. A manual valve is provided to discharge
3. The automatic transmission according to claim 1, wherein the manual valve switches between opening and closing of the second oil passage and the third oil passage by movement of a spool interlocked with operation of a shift lever. Hydraulic control device. 4. The torque capacity of the starting fastening element generated by the held fastening hydraulic pressure is equal to or less than the torque transmitted by the starting fastening element during creep travel. The hydraulic control device for the automatic transmission according to the item. The automatic transmission has a belt-type continuously variable transmission that can change continuously by changing the groove width of the driving pulley and the driven pulley by hydraulic pressure,
The drive side pulley has a torque capacity of the starting fastening element generated by the held fastening hydraulic pressure when the hydraulic pressure supplied from the oil pump to the starting fastening element becomes equal to the held fastening hydraulic pressure. The hydraulic control device for an automatic transmission according to any one of claims 1 to 3, wherein the torque is less than or equal to a torque that can be transmitted. The torque capacity of the starting fastening element generated by the held fastening hydraulic pressure is less than the torque that can be transmitted by the driving pulley when the hydraulic pressure supplied to the driving pulley and the driven pulley is zero. The hydraulic control device for an automatic transmission according to claim 5, wherein:

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