JP5807110B2 - Power transmission control device for vehicle - Google Patents

Description

  The present invention relates to a power transmission control device in a vehicle equipped with a CVT (continuously variable transmission).

  In a CVT-equipped vehicle, the power transmission between the engine and the CVT is automatically switched to a disconnected state during a period in which the vehicle is temporarily stopped while waiting for a signal or traffic jams. A technique is known that prevents the loss of engine power and prevents the rotation of drive wheels by restraining the belt applied to the output pulley by increasing the clamping pressure of the output pulley of the CVT (eg, patent) Reference 1).

JP 2004-324860 A

  However, even during a limited period during which the CVT-equipped vehicle is temporarily stopped, applying a high pressure to the belt causes deterioration of the belt.

  On the other hand, in a CVT-equipped vehicle, when the driver sets the shift lever to the parking range and stops the vehicle on the slope, the output pulley of the CVT is restrained from rotating as a parking gear by the parking pole, A large torsional torque from the drive wheel is acting. Therefore, in such a state, if the input pulley of the CVT does not secure a sufficient clamping pressure, the driver next moves the shift lever from the parking range to the D range or the like in order to restart the vehicle. When the output range pulley is switched to the forward range, the output side pulley strongly rotates integrally with the belt due to the torsional torque, so that the belt slips in the input side pulley, causing a reduction in the belt life.

  An object of the present invention is to provide a vehicle power transmission control device that prevents deterioration of a transmission element of a continuously variable transmission by controlling a clamping pressure of the continuously variable transmission during a stop period in a state where a power source is operated. It is to be.

The power transmission control device for a vehicle according to the present invention includes a parking gear, a restraining member that restrains the rotation of the parking gear by being displaced with respect to the parking gear, and a parking range or others by an operation by the driver. a power transmission control device for a vehicle and a range switching means for switching to the range of setting the power transmission state, the input side element power from a power source of the vehicle is input, power to a drive wheel of the vehicle an output side element for outputting, and a transmission element for transmitting power to the output side element from the input element, the gear ratio in accordance with the clamping pressure of the input-side element and the output-side element relative to the transmission element A continuously variable transmission that is adjusted, a clamping pressure control unit that controls clamping pressure of the input side element and the output side element, and connection / disconnection for connecting / disconnecting power transmission between the power source and the input side element There are a location, and a stop detecting unit for detecting whether or not the stop state, and the brake operation detecting unit that detects whether the brake is being operated for braking the drive wheel, power transmission state to the parking range When the parking range detector detects that the parking range has been switched from the non-parking range to the parking range, the restraining member is provided between the connecting / disconnecting device and the drive wheel. And a switching unit that switches the connection / disconnection device to a disconnection state after being displaced to a position that restrains rotation of the parking gear, and the clamping pressure control unit is configured to stop the connection / disconnection device in a stop period when the connection / disconnection device is in a disconnection state When the brake is in operation, the clamping pressure of the input side element and the output side element is controlled to a first value larger than the previous narrow pressure, and the brake is released. When it is in is characterized by controlling said first value is smaller than the second value.

According to the present invention, the input side element and the output side element of the continuously variable transmission restrain the transmission element by the first clamping pressure in the parking range and the stopping period in which the connecting / disconnecting device is in the disconnected state. The slippage of the transmission element with respect to the input side element and the output side element is prevented. In addition, during the stopping period, as the brake is released, the clamping pressure between the input side element and the output side element is switched from a large first value to a small second value. Therefore, even in a parking period where the connecting / disconnecting device is in a disconnected state, the transmission element of the continuously variable transmission is not supplied from the input side element and the output side element in the stopping period when the brake is not operating. Since the large narrow pressure is released, the life reduction of the transmission element is suppressed.

  Preferably, in the vehicle power transmission control device, when the clamping pressure control unit is switched from the disconnected state to the connected state during the stop period in which the connecting / disconnecting device is in the disconnected state and the brake is being operated. The clamping pressure of the input side element and the output side element is held at the first value for the first predetermined time from the time of switching, and the clamping pressure before the first value is reached after the first predetermined time has elapsed. Start to drop.

  As a result, during the first stop period when the connecting / disconnecting device is switched from the disconnected state to the connected state during the stop period in which the brake is operating, the holding pressure between the input side element and the output side element of the continuously variable transmission is reduced. By maintaining the first value, the rotation of the input side element and the output side element is restricted. As a result, when the connection / disconnection device is switched from the disconnected state to the connected state, slippage of the transmission element due to torque imbalance between the input side element and the output side element is avoided, and the life of the transmission element is reduced. It is suppressed.

  Preferably, the clamping pressure control unit includes a timer that measures a second predetermined time from when the brake operation detection unit detects the switching from the brake operation to the non-operation, and the timer is a second predetermined time. After measuring the time, the clamping pressure of the input side element and the output side element is switched from the first value to the second value.

  After the measurement for the second predetermined time, the switching from the first value to the second value can be smoothly performed for the clamping pressure of the input side element and the output side element. Further, by delaying the switching from the first value to the second value for the second predetermined time, it is possible to prevent frequent fluctuations in the narrow pressure due to the short-time operation of the brake.

A large torsional torque from the drive wheels acts on the parking gear during a period when the vehicle equipped with the parking gear stops on the slope in the parking range . Therefore, when the parking range for resuming driving is switched to the non-parking range during this period, the output side element is subjected to a large torsional torque from the drive wheel as the parking gear rotation is released by the restricting member. Therefore, the transmission element may rotate together with the transmission element, and the transmission element may slide on the input side element. During the first predetermined time, a large torsional torque from the drive wheels acts on the output side element by holding the clamping pressure between the input side element and the output side element of the continuously variable transmission at the first value. Sometimes, the transmission element is prevented from slipping on the input side element, and the life reduction of the transmission element is suppressed.

1 is a configuration diagram of a vehicle power transmission device and a CVT control device. The block diagram of a parking gear and a parking pole. Explanatory drawing about the slip of the V belt in the input side pulley when the parking range is canceled. Explanatory drawing of the action | operation of the side pressure control of the input side pulley and output side pulley of CVT of the stop period implemented by ECU for CVT. The flowchart of the 1st part of the side pressure control of the input side pulley and output side pulley of CVT of a stop period. The flowchart of the 2nd part of the side pressure control of the input side pulley and output side pulley of CVT of a stop period. The flowchart of another side pressure control which changed a part of flowchart of FIG.

  In FIG. 1, a vehicle (automobile) 1 is equipped with a power transmission device 2 and a CVT control device 3. The CVT control device 3 performs power transmission from the engine 7 to the left and right drive wheels 14. The CVT control device 3 includes a fluid torque converter 8, a forward clutch 9, a forward / reverse switching device 10, a CVT 11, a parallel shaft gear device 12, and a differential device 13 in the order of transmission of power from the engine 7 to the drive wheels 14. ing. The plurality of bearings 18 are disposed in each part in the power transmission device 2 and rotatably support corresponding shafts.

  The CVT 11 includes an input pulley 23, an output pulley 24, a V belt 55 (FIG. 3), an input hydraulic servo 25, and an output hydraulic servo 26.

  The input-side pulley 23 includes a movable portion 23a that can move along the input shaft and a fixed portion 23b that is fixed. The input-side hydraulic servo 25 controls the side pressure of the movable portion 23a to control the input-side pulley. 23, the clamping pressure of the V-belt 55 is adjusted. The output-side pulley 24 includes a movable portion 24a that can move along the output shaft and a fixed portion 24b that is fixed. The output-side hydraulic servo 26 controls the side pressure of the movable portion 24a to control the output-side pulley. 24, the clamping pressure of the V belt 55 is adjusted.

  In the input-side pulley 23 and the output-side pulley 24, the side pressure refers to a pressure that presses the movable parts 23a, 24a in the axial direction toward the fixed parts 23b, 24b. As the side pressure increases and the pinching pressure increases, the wrapping radius of the V belt 55 in the input side pulley 23 or the output side pulley 24 increases. The transmission ratio of the CVT 11 is controlled by side pressure control of the input side pulley 23 and the output side pulley 24.

  The intermediate shaft 30 passes through the center hole of the input side pulley 23 and the input side hydraulic servo 25 along the center line, and the turbine runner as an output part of the fluid torque converter 8 at both ends and the forward / reverse switching device 10. It is fixed to the sun gear as an input part.

  The forward clutch 9 is interposed between the intermediate shaft 30 and the input pulley 23, and is in a contact state when a shift lever (not shown) is in the forward range of the D (drive) range or the S (sport) range. When the shift lever is in the stop range of the N (neutral) range or the P (parking) range, or when the shift lever is in the reverse range of the R (reverse) range, the disconnection state is established.

  The brake 29 is interposed between the ring gear of the forward / reverse switching device 10 and a predetermined fixing member outside the forward / reverse switching device 10 and switches between fixing and releasing the ring gear. When the shift lever is in the R range, the brake 29 fixes the ring gear and transmits the power of the intermediate shaft 30 to the input side pulley 23 with the rotation direction reversed, and the shift lever is not in the R range. If in range, unlock ring gear and stop power transmission.

  The CVT control device 3 includes a CVT ECU (ECU: electronic control device) 34, an engine speed sensor 35, an intermediate shaft speed sensor 36, an input side speed sensor 37, an output side speed sensor 38, an outgear sensor 39, a brake sensor 40, A position sensor 41 and a servo hydraulic pressure sensor 42 are provided. The CVT ECU 34 receives input signals from the engine speed sensor 35, the intermediate shaft speed sensor 36, the input side speed sensor 37, the output side speed sensor 38, the outgear sensor 39, the brake sensor 40, the position sensor 41, and the servo hydraulic pressure sensor 42. Based on this, a servo signal is sent to the input-side hydraulic servo 25 to control the side pressure of the input-side pulley 23 and the output-side pulley 24 to control the clamping pressure of the V-belt 55 by the input-side pulley 23 and the output-side pulley 24.

  The engine speed sensor 35 detects the rotational speed of the engine 7. The intermediate shaft speed sensor 36 detects the rotational speed of the intermediate shaft 30. The input side speed sensor 37 detects the rotational speed of the input side pulley 23. The output side speed sensor 38 detects the rotational speed of the output side pulley 24.

  The out gear sensor 39 detects the in gear and the out gear of the power transmission device 2 from the rotation direction of the ring gear of the forward / reverse switching device 10. The ring gear of the forward / reverse switching device 10 rotates in the same direction as the intermediate shaft 30 when the forward clutch 9 is in the engaged state, that is, in the in-gear state, and the forward clutch 9 is in the disconnected state and the forward / reverse switching is performed. When the brake of the device 10 is in the disconnected state, that is, when it is in the out gear, it rotates in the direction opposite to the intermediate shaft 30. In the in-gear, the output shaft of the engine 7 and the driving wheel 14 are in a power connection state, and in the out-gear, the power connection between the output shaft of the engine 7 and the driving wheel 14 is cut off.

  The brake sensor 40 detects whether or not the driver is operating the foot brake based on whether or not the driver depresses the brake pedal. The position sensor 41 detects which range of N, P, D, S and R corresponds to the position of the shift lever. The servo hydraulic pressure sensor 42 detects the hydraulic pressure of the input side hydraulic servo 25 of the CVT 11.

  FIG. 2 shows the operating state of the parking pole 50. The parking gear 45 includes teeth 46 and grooves 47 that are alternately formed at equal angular intervals in the circumferential direction on the outer peripheral portion of the fixed portion 24 b of the output pulley 24. The parking pole 50 is swingably supported in the vicinity of the parking gear 45, and in the P range, the claw portion 51 is displaced toward the parking gear 45 and enters the groove 47. As a result, when the parking gear 45 attempts to rotate relative to the claw portion 51, the claw portion 51 abuts against the side edge of the tooth 46 in the circumferential direction, and the rotation of the output pulley 24, that is, the rotation of the drive wheel is prevented. The On the other hand, since the parking gear 45 retreats the claw portion 51 from the groove 47 except in the P range, the contact between the claw portion 51 and the teeth 46 in the circumferential direction is avoided, and the rotation of the output pulley 24 is prevented. That is, rotation of the drive wheel is allowed.

  During the period when the vehicle 1 is stopped in the P range on the uphill road, the torsional torque Da from the driving wheel 14 travels forward on the members between the driving wheel 14 and the parking gear 45 including the output side pulley 24 of the CVT 11. It acts in the direction of rotation opposite to the rotational torque from the engine power at the time. In this embodiment, the parking gear 45 is formed integrally with the output pulley 24 of the CVT 11. However, the parking gear 45 may be provided on a downstream member from the output pulley to the drive wheel.

  FIG. 3 is an explanatory diagram of a problem when the P range is canceled while the vehicle is stopped on an uphill road. As described in FIG. 2, the torsional torque Da from the drive wheel 14 acts on the output side pulley 24 of the CVT 11. Next, when the P range is released, the rotation restriction of the parking gear 45 is released. The output pulley 24 rotates together with the V belt 55 with a strong rotational torque in the rotational direction of the torsional torque, and the V belt 55 moves in the direction Db in FIG. This causes the life of the V-belt 55 to be reduced. In the vehicle 1, as will be described later, appropriate side pressure control of the input side pulley 23 and the output side pulley 24 is performed to eliminate such a problem.

  The power transmission device 2 and the CVT control device 3 are examples of the power transmission control device of the present invention. The engine 7 is an example of a power source of the present invention. The forward clutch 9 is an example of a connection / disconnection device of the present invention. The input side pulley 23 is an example of the input side element of the present invention. The output side pulley 24 is an example of the output side element of the present invention. The input side hydraulic servo 25 and the output side hydraulic servo 26 are examples of the clamping pressure control unit of the present invention. The CVT ECU 34 is an example of a switching unit of the present invention. The output side speed sensor 38 is an example of a stop detection unit of the present invention. The brake sensor 40 is an example of a brake operation detection unit of the present invention. The position sensor 41 is an example of a parking position detection unit of the present invention. The parking pole 50 is an example of a restraining member of the present invention. The V belt 55 is an example of the transmission element of the present invention.

  FIG. 4 is an explanatory diagram of the lateral pressure control of the input side pulley 23 and the output side pulley 24 during the stop period. In this CVT 11, if the hydraulic pressure of the input side hydraulic servo 25 is controlled to control the side pressure of the input side pulley 23, the side pressure of the output side pulley 24 automatically becomes a value corresponding to the side pressure of the input side pulley 23. It comes to follow. In FIG. 4, the low level and the high level are referred to as “0” and “1”, respectively. Each item in FIG. 4 will be described in order from the top.

  In “stop / non-stop”, “0” means a non-stop state (running state), and “1” means a stop state. The vehicle 1 is in a stopped state when the vehicle speed = 0, and is in a non-stopped state when the vehicle speed> 0. The vehicle speed can be detected from the output of the output side speed sensor 38 as a vehicle speed sensor.

  In “foot brake”, “0” means that the driver has not depressed the brake pedal and the foot brake is in an inoperative state, and “1” means that the driver has depressed the brake pedal, It means that the foot brake is in operation. Whether or not the driver has depressed the brake pedal is detected from the output of the brake sensor 40.

  In the “shift position”, “0” means that the shift lever is in the D, S, or R travel range, and “1” means that the shift lever is in the N or P non-travel range. Whether the shift lever is in the travel range or the non-travel range is detected from the output of the position sensor 41.

  In “in-gear ready”, “0” means that in-gear preparation is not completed, and “1” means that in-gear preparation is completed. The in-gear preparation is not completed for a predetermined time immediately after the start, and in this incomplete state, switching from the in-gear to the out-gear is prohibited to avoid engine stall.

  In “vehicle speed”, the higher the level is, the higher the vehicle speed is, and level = 0 means that the vehicle speed of the vehicle 1 is 0 m / s. Since the drive wheels 14 and the output side pulley 24 of the CVT 11 are always in a power connection state, the vehicle speed of the vehicle 1 can be detected from the output of the output side speed sensor 38.

  When the shift position is switched from the stop range to the forward range during the stop period in which the shift position is in the stop range, the “side pressure holding timer” refers to an elapsed time Tk (first predetermined time of the present invention). This is a timer that measures time). In FIG. 4, the level of “side pressure holding timer” indicates the value of the side pressure holding timer.

  The “standby pressure transition timer” is an elapsed time Tr (second time of the present invention) when the driver switches the foot brake from operating to non-operating during the stop period when the shift position is in the stop range. This is a timer for measuring an example of a predetermined time. In FIG. 4, the level of the “standby pressure transition timer” indicates the value of the standby pressure transition timer.

  The “side pressure addition state” refers to a state in which a predetermined addition (addition pressure> 0) is performed with respect to the reference pressure Po for the side pressures of the input side pulley 23 and the output side pulley 24 of the CVT 11. The reference pressure Po is a target side pressure of the output pulley 24 when the gear ratio control of the CVT 11 is being performed.

  The reference pressure Po changes according to the target gear ratio at each time point during the traveling period. A reference pressure Po (a reference pressure Po in STEP 10 to be described later) used in a period in which the “side pressure addition state” is added is a side pressure of the input pulley 23 and the output pulley 24 immediately after stopping. The level of “side pressure P of the input / output side pulley” in FIG. 4 means the value of the side pressure P of the input side pulley 23 and the output side pulley 24.

  With reference to FIG. 4, the flow charts of FIGS. 5 and 6 regarding the side pressure control of the output side pulley 24 of the CVT 11 by the power transmission device 2 will be described. The side pressure control in FIGS. 5 and 6 is executed by executing a predetermined side pressure control program in the CVT ECU 34, and the predetermined side pressure control program is executed by a time interruption at regular intervals.

  The predetermined side pressure control program is executed by the CVT ECU 34. Accordingly, the execution subject of each of the following STEPs is all CVT ECU 34.

  In STEP 1, the CVT ECU 34 checks whether or not in-gear is permitted. If it is determined that permission is granted, the CVT ECU 34 executes STEP 2. If it determines that permission is not allowed, it executes STEP 9. The vehicle 1 is placed in a state where the in-gear is not permitted (prohibited) for a predetermined time immediately after starting to avoid engine stall. In FIG. 4, in-gear permission is not indicated before time t1, and in-gear permission is indicated after time t1.

  The ECU for CVT 34 compares the vehicle speed V with the threshold value Vr in STEP2, and if it is determined that V ≦ Vr, it executes STEP3 next, and if it determines that V> Vr, it executes STEP9 next. For example, Vr is set to a value slightly larger than 0 m / s in order to discriminate between stopping and non-stopping. In FIG. 4, the vehicle 1 starts decelerating from the time t2 when the foot brake starts to operate due to a red light at an intersection, traffic congestion, and the like.

  In STEP 3, the CVT ECU 34 determines whether or not the vehicle 1 is in a complete stop state (vehicle speed V = 0). If it is determined that the vehicle is not stopped, STEP 9 is executed next. The CVT ECU 34 can determine from the output of the output side speed sensor 38 as a vehicle speed sensor whether or not the vehicle 1 is completely stopped. In FIG. 4, after time t3, the vehicle speed becomes 0 m / s, and the vehicle is completely stopped.

  In STEP 4, the CVT ECU 34 determines whether the shift lever is in the non-traveling range or the traveling range, and when it is determined to be the non-traveling range, next executes STEP 5 and when it is determined to be the traveling range, Next, STEP9 is executed.

  In FIG. 4, at time t4, the shift position is switched from the travel range to the non-travel range. Further, along with this switching, the forward clutch 9 is switched from the contact state to the disengaged state, and the power transmission device 2 is switched from the in-gear to the out-gear.

  In STEP5, the CVT ECU 34 determines whether the power transmission device 2 is in the in-gear or the out-gear based on the output of the out-gear sensor 39. If so, STEP 21 (FIG. 6) is executed next.

  In STEP 6, the CVT ECU 34 checks the value of the side pressure holding timer. When the value of the side pressure holding timer is> 0, the CVT ECU 34 executes STEP7 next, and when the value of the side pressure holding timer is 0, next executes STEP9. Note that the values of the side pressure holding timer and the standby pressure transition timer, which will be described later, are set to the default value of 0 at the initial setting when the engine 7 is started, and until STEP 25 or 26 (FIG. 6) described later is executed. 0.

  In STEP 7, the CVT ECU 34 decrements (decrements) the value of the side pressure holding timer by one. STEP 7 is executed every time the lateral pressure control program of FIG. 5 and FIG. 6 is executed at regular time intervals. Therefore, when switching from out-gear to in-gear at time t10, the value of the side pressure holding timer gradually decreases from time t10. At time t11.

  In STEP 8, the CVT ECU 34 substitutes the restraining added pressure Pk for the added pressure Pa. The restraining additional pressure Pk is an example of a first value for the narrow pressure of the input pulley and the output pulley in the present invention. The restraining addition pressure Pk is set as a side pressure addition amount that prevents the output side pulley 24 from rotating when the V belt 55 is pressed against the output side pulley 24 by being added to the reference pressure Po. The CVT ECU 34 executes STEP 10 after executing STEP 8.

  In STEP 9, the CVT ECU 34 substitutes 0 for the additional pressure Pa. The CVT ECU 34 executes STEP 10 after executing STEP 9.

  In FIG. 4, since the value of the side pressure holding timer becomes 0 at t11, after time t11, it is determined that the value of the side pressure holding timer is 0 at STEP 6 described above, and 0 is substituted for the added pressure Pa at STEP9. The

  In STEP 10, the CVT ECU 34 substitutes the reference pressure Po + the added pressure Pa for the target side pressure of the input pulley 23 and the output pulley 24.

  In STEP 11, the CVT ECU 34 increases or decreases the side pressures of the input pulley 23 and the output pulley 24 so as to become the target side pressure while referring to the detected pressure of the servo hydraulic pressure sensor 42.

  In STEP21, the CVT ECU 34 checks whether the foot brake is in an activated state or an inoperative state based on the output of the brake sensor 40, and if it is determined as an inoperative state, executes the STEP22 next, If it is determined that the actuator is in the operating state, STEP 25 is executed next.

  In STEP 22, the CVT ECU 34 checks the value of the standby pressure transition timer. If the value of the standby pressure transition timer is 0, then the CVT ECU 34 executes STEP 23, and if the value of the standby pressure transition timer is> 0, Next, STEP24 is executed.

  In STEP23, the CVT ECU 34 substitutes the standby additional pressure Pr for the additional pressure Pa. The standby addition pressure Pr is an example of a second value for the pinching pressure between the input pulley and the output pulley in the present invention. The standby additional pressure Pr is set in preparation for the time when the vehicle 1 resumes running from the stop, that is, for the time when the shift control of the CVT 11 is resumed. It is set as a side pressure addition amount in a standby state that becomes Po (side pressure of the output side pulley 24 immediately after stopping). A relation of Pk ≧ Pr ≧ 0 is set between the restraining addition pressure Pk and the standby addition pressure Pr.

  After executing STEP23, the CVT ECU 34 executes STEP10. The additional pressure Pa that has been set as the standby additional pressure Pr in STEP 23 is included in the target side pressure together with the reference pressure Po during the subsequent execution of STEP 10. During the period of target side pressure = Po + Pr, when the vehicle 1 is in a completely stopped state (STEP 3), the shift lever is in the non-traveling range (STEP 4), and the foot brake is being operated (STEP 21), the foot brake is It is after time t6 when the operation state is switched to the non-operation state.

  That is, until time t6, the side pressure of the input side pulley 23 and the output side pulley 24 is Po + Pk described in STEP 27 described later. In addition, the standby pressure transition timer is activated from time t6, the elapsed time Tr is measured, and the target side pressure is still maintained at Po + Pk until time t7 when the predetermined time Tr has elapsed from time t6.

  The side pressures of the input-side pulley 23 and the output-side pulley 24 gradually decrease toward Po + Pr from time t7 and become Po + Pr at time t8. The side pressures of the input side pulley 23 and the output side pulley 24 are maintained at Po + Pr from time t8 until time t9 when the driver depresses the brake pedal and the foot brake is actuated again. At time t9, the side pressure immediately becomes Po + Pk. Return.

  If the driver switches the shift lever from the non-traveling range to the traveling range during the period when the side pressures of the input pulley 23 and the output pulley 24 are Po + Pr, at the time of executing the next side pressure control program, After the determination of STEP4, the CVT ECU 34 executes STEP9. As a result, the side pressures of the input side pulley 23 and the output side pulley 24 do not return to Po + Pk, but fall from Po + Pr to Po.

  During the period from time t8 to time t9, maintaining the side pressure of the input pulley 23 and the output pulley 24 from Po + Pk to Po + Pr lower than that suppresses the life reduction of the V belt 55. In addition, during the period from t8 to t9, since the driver releases the depression of the brake pedal, it is determined that the release of the foot brake is a brake release that the driver determines that there is no particular problem, Even if the side pressure of the input pulley 23 and the output pulley 24 is set to Po + Pr lower than Po + Pk and the stopping force of the vehicle 1 is reduced, the reduction of the side pressure between t8 and t9 does not hinder the driving.

  Also, immediately after the time t6 when the foot brake is switched from the operating state to the non-operating state, the side pressure of the input side pulley 23 and the output side pulley 24 is not lowered to Po + Pr, and the time t7 after a predetermined time Tr has elapsed from the time t6. The reason for starting to descend is to prevent frequent fluctuations in the narrow pressure due to a short time operation of the brake. When the driver inadvertently releases the foot brake, the driver depresses the brake pedal within the predetermined time Tr. In this case, the side pressures of the input pulley 23 and the output pulley 24 are maintained at Po + Pk. Will remain.

  In STEP 24, the CVT ECU 34 decrements (decrements) the value of the standby pressure transition timer by one. After executing STEP 24, the CVT ECU 34 executes STEP 27. STEP 24 is executed each time the lateral pressure control program of FIGS. 5 and 6 is executed at regular time intervals, so that the value of the standby pressure transition timer gradually decreases from time t6 in FIG. 4 and becomes 0 at time t7. become.

  In STEP 25, the CVT ECU 34 sets a predetermined value Ck in the side pressure holding timer. The conditions for executing STEP 25 are that the vehicle 1 is in a completely stopped state (STEP 3), the shift lever is in the non-traveling range (STEP 4), and the foot brake is being operated (STEP 21).

  In FIG. 4, a predetermined value Ck is set in the side pressure holding timer at time t4. Ck is a predetermined value corresponding to Tk between t10 and t11 in FIG.

  After STEP 25 is executed and the predetermined value Ck is set in the side pressure holding timer, the side pressure control program shown in FIGS. 5 and 6 is executed at regular intervals. The hold timer value is decremented by one. As a result, the value of the side pressure holding timer becomes 0 at time t11. With the first execution of STEP 6 after time t11, the added pressure Pa becomes 0 in STEP9, and the side pressures of the input side pulley 23 and the output side pulley 24 gradually decrease with an appropriate slope after time t11, and become the reference at time t12. The pressure becomes Po.

  Note that Po + Pk at time t10 is an example of a first value for the clamping pressure. The reference pressure Po at time t12 is an example of the clamping pressure before the first value after the first predetermined time has elapsed.

  In STEP 26, the CVT ECU 34 sets a predetermined value Cr in the standby pressure transition timer. Cr is a predetermined value corresponding to Tr between t6 and t7 in FIG.

  In STEP 27, the CVT ECU 34 substitutes the restraining additional pressure Pk for the additional pressure Pa. After executing STEP 27, the CVT ECU 34 executes STEP 10. In STEP 27, the additional pressure Pa that has been set as the restricting additional pressure Pk is added to the target side pressure together with the reference pressure Po in STEP 10. The period when the target side pressure = Po + Pk is (a) the period of t4−t6 and t9−t10 as the period when the vehicle 1 is in a completely stopped state, the shift lever is in the non-traveling range, and the foot brake is being operated. (B) When the vehicle 1 is in a completely stopped state, the shift lever is in the non-traveling range, and the foot brake is being operated, the foot brake is switched from the operating state to the non-operating state, and the switching time t6 (C) When the vehicle 1 is in a completely stopped state, the shift lever is in the non-traveling range, and the foot brake is being operated. The shift lever is switched from the non-traveling range to the traveling range, and includes a period from t10 to t11 as a period from the switching time until the predetermined time Tk elapses.

  The reason why the lateral pressures of the input pulley 23 and the output pulley 24 are maintained at Po + Pk during the period of t4 -t6 and t9 -t10 in (a) is that the driver can use the shift lever during the stop period of the uphill or downhill road. This is to prevent the V-belt 55 in the input pulley 23 described with reference to FIG. 3 from slipping even when the power transmission device 2 changes from the out gear to the in gear by switching from the P range to the travel range. As a result of preventing slipping, the life reduction of the V-belt 55 can be suppressed.

  The reason why the side pressure of the input side pulley 23 and the output side pulley 24 is maintained at Po + Pk during the period t6-t7 in (b) will be described in the standby state of the input side pulley 23 and the output side pulley 24 when STEP 23 is explained. The reason why the addition pressure Pr is not started from t6 but from t7 has been described.

  The reason why the side pressures of the input pulley 23 and the output pulley 24 are maintained at Po + Pk during the period of t10-t11 in (c) is that the driver moves the shift lever from the P range during the stop period of the vehicle 1 on the uphill or downhill road. This is to prevent the V belt 55 in the input side pulley 23 described with reference to FIG. 3 from slipping even when the power transmission device 2 changes from the out gear to the in gear by switching to the travel range. As a result of preventing slipping, the life reduction of the V-belt 55 can be suppressed.

  FIG. 7 shows a modification of part of the flowchart of FIG. The changed part is STEP 31, which is executed instead of STEP 5 in FIG.

  The CVT ECU 34 executes STEP 31 after STEP 4 and before STEP 6, and determines whether or not the shift position is in the P range. When it is determined that the CVT ECU 34 is in the P range, STEP 21 (FIG. 6) is executed next. When it is determined that the C range is not in the P range, STEP 6 is executed next.

  As a result, only the stop period in the P range, that is, the stop period in the N range among the stop periods is eliminated, and the addition pressure control of the input side pulley 23 and the output side pulley 24 in FIG. 6 is performed.

  The present invention is not limited to the above-described embodiment, and various modifications can be made within the scope of the gist.

  For example, the CVT is not limited to the belt type CVT 11, and a toroidal type CVT can also be used. The input disk, output disk, and power roller in the toroidal CVT correspond to the input side element, output side element, and transmission element in the present invention, respectively.

  In the above embodiment, the parking gear 45 is formed on the outer peripheral portion of the fixed portion 24b of the output pulley 24. However, the parking gear 45 can be fixed to the side surface of the fixed portion 24b.

  The brake sensor 40 detects the operation and non-operation of the foot brake, but may detect the operation and non-operation of the hand brake instead of the foot brake.

  Further, the standby addition pressure Pr in STEP 23 is Pr ≧ 0, but it may be Pr <0. That is, when the forward clutch 9 is disengaged and the brake sensor 40 is not operated, the side pressures of the input side pulley 23 and the output side pulley 24 may be smaller than the narrow pressure at the time of resuming traveling.

  As described above, in the CVT 11 of the embodiment, when the side pressure of the input side pulley 23 is controlled by the hydraulic pressure of the input side hydraulic servo 25, the side pressure of the output side pulley 24 automatically follows the side pressure of the input side pulley 23. It is like that. The control of the clamping pressure of the input side element (for example, the input side pulley 23) and the output side element (for example, the output side pulley 24) in the present invention is not limited to the control of only the input side element, but the control of only the output side element. Or the clamping pressure of both the input side element and the output side element can be controlled.

DESCRIPTION OF SYMBOLS 1 ... Vehicle, 2 ... Power transmission device (vehicle power transmission control device), 3 ... CVT control device (vehicle power transmission control device), 7 ... Engine (power source), 9 ..Forward clutch (connecting / disconnecting device), 11 ... CVT (continuously variable transmission), 14 ... drive wheels, 23 ... input side pulley (input side element), 24 ... output side pulley ( Output side element), 25... Input side hydraulic servo (clamping pressure control unit), 26... Output side hydraulic servo (clamping pressure control unit), 34... CVT ECU (switching unit), 38. Output speed sensor (stop detection unit), 40 ... brake sensor (brake operation detection unit), 41 ... position sensor (parking position detection unit), 45 ... parking gear, 50 ... parking pole (Restraint member), 55... V belt (transmission element).

Claims (3)

A parking gear, a restraining member for restraining or releasing the restraint of the parking gear by displacement with respect to the parking gear, and a range for switching to a parking range or a range for setting another power transmission state by an operation by the driver A vehicle power transmission control device comprising switching means,
An input-side element to which power from a power source of the vehicle is input, and an output side element for outputting power to a drive wheel of the vehicle, and a transmission element for transmitting power to the output side element from the input element a, a continuously variable transmission gear ratio is adjusted in accordance with the clamping pressure of the input-side element and the output-side element relative to the transmission element,
A clamping pressure control unit for controlling the clamping pressure of the input side element and the output side element;
A connection / disconnection device for connecting / disconnecting power transmission between the power source and the input side element;
A stop detection unit for detecting whether or not the vehicle is stopped;
A brake operation detection unit for detecting whether or not a brake for braking the drive wheel is in operation ;
A parking range detector for detecting that the power transmission state is in the parking range;
When the parking range detector detects that the non-parking range has been switched to the parking range, the restraining member restrains the rotation of the parking gear provided between the connecting / disconnecting device and the drive wheel. And a switching unit that switches the connection / disconnection device to a disconnected state after being displaced,
When the brake is being operated during a stop period in which the connecting / disconnecting device is in a disconnected state, the clamping pressure control unit reduces the clamping pressure of the input side element and the output side element from the previous narrow pressure A vehicular power transmission control device that controls to a large first value and controls to a second value smaller than the first value when the brake is being released. In the vehicle power transmission control device according to claim 1,
When the connecting / disconnecting device is switched from a disconnected state to a connected state in a stopping period in which the connecting / disconnecting device is in a disconnected state and the brake is being operated, the clamping pressure control unit The clamping pressure of the output side element is maintained at the first value for a first predetermined time from the time of switching, and after the first predetermined time has elapsed, the clamping pressure before the first value starts to decrease. A vehicle power transmission control device. In the vehicle power transmission control device according to claim 1 ,
The clamping pressure control unit includes a timer that measures a second predetermined time from when the brake operation detection unit detects a change from the operation of the brake to the non-operation, and the timer is a second predetermined time After measuring time, the vehicle power transmission control apparatus which switches the clamping pressure of the input side element and the output side element from the first value to the second value.