JP2011099470A - Control device for vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a control device for a vehicle capable of controlling the protrusion of a snap ring of a frictional engagement device, in a vehicle mounted with the frictional engagement device including the snap ring for regulating the movement of the frictional engagement element. <P>SOLUTION: During the traveling of a vehicle, a frictional engagement device (a clutch brake engaged in the traveling of a vehicle) is switched to a non-engagement state in a state that an accelerator is turned off and it is determined that the traveling in the state of turning off the accelerator may be continued (for example, in a state that a downward grade detected by a grade sensor is a determination threshold or smaller). A frictional force causing the protrusion of the snap ring can be released (canceled) by switching the frictional engagement device to a non-engagement state during coasting traveling in the state of turning off the accelerator (accelerator opening=0%), and the protrusion of the snap ring can be thereby suppressed. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a control device applied to a vehicle in which a friction engagement device is provided in a power transmission path between an engine (internal combustion engine) and drive wheels.

  In a vehicle equipped with an engine, the gear ratio between the engine and the drive wheel is automatically set optimally as a transmission that properly transmits the torque and rotation speed generated by the engine to the drive wheel according to the running state of the vehicle. Automatic transmissions are known.

  As an automatic transmission mounted on a vehicle, for example, a stepped (planetary gear type) automatic transmission that sets a gear stage using a friction engagement device such as a clutch and a brake and a planetary gear unit, There is a continuously variable transmission (CVT) that continuously adjusts the ratio.

  In a vehicle equipped with a stepped automatic transmission, a shift map having a shift line (gear stage switching line) for obtaining an optimum gear stage according to the vehicle speed and accelerator opening (or throttle opening). Is stored in an ECU (Electronic Control Unit) or the like, and a target gear stage is calculated with reference to a shift map based on the vehicle speed and the accelerator opening, and frictional factors such as clutches and brakes are calculated based on the target gear stage. The gear (gear ratio) is automatically set by engaging or releasing the combined device in a predetermined state.

  Belt type continuously variable transmissions have a belt wound around a primary pulley (input pulley) and a secondary pulley (output pulley) that have pulley grooves (V grooves), and the width of the pulley groove of one pulley is increased. At the same time, by narrowing the width of the pulley groove of the other pulley, the belt winding radius (effective diameter) for each pulley is continuously changed to set the transmission ratio steplessly. ing.

  In a vehicle equipped with a belt type continuously variable transmission, a forward / reverse switching device is provided in a power transmission path between a torque converter for transmitting engine torque and the belt type continuously variable transmission. The forward / reverse switching device includes a planetary gear mechanism, a forward clutch (forward clutch) that is a friction engagement device, a reverse brake (reverse brake), and the like.

  A friction engagement device applied to such a forward / reverse switching device or a stepped automatic transmission, for example, can transmit or transmit torque by engaging or releasing a friction engagement element composed of a plurality of friction plates. It is a device that shuts off. Further, such a friction engagement device includes a snap ring for restricting axial movement of a friction engagement element including a plurality of friction plates (see, for example, Patent Documents 1 to 3).

  For example, as shown in FIG. 13, the snap ring is not formed into a complete ring shape, but is processed into a C-shaped shape in which a part of the ring shape is divided. For example, a friction engagement element (a plurality of friction plates) is fitted. It is inserted into a groove provided in a tooth portion (convex portion) of the spline to be mated.

  In addition, there exists a technique of the following patent document 4 as a technique regarding control of the automatic transmission mounted in a vehicle. In the technique described in Patent Document 4, the automatic transmission is automatically changed from the drive range state to the neutral state only when the accelerator close signal (accelerator off state) continues for a predetermined time, so that the time of traffic congestion can be obtained. Thus, even if the accelerator is repeatedly turned on and off, the shift shock is prevented from occurring.

JP 2003254431 A JP 2008-064276 A JP 2008-128365 A Japanese Utility Model Publication No. 61-073863

  By the way, in a friction engagement device (clutch / brake) having a snap ring that restricts the movement of the friction engagement element, when a positive or negative torque input is applied in the engaged state, the friction plate (or clutch drum, etc.) and the snap ring In some cases, the snap ring is pulled into the inner diameter side by the frictional force between and a portion of the snap ring protruding from the groove (see a two-dot chain line in FIG. 13).

  Note that Patent Document 4 only describes that the automatic transmission shifts to the neutral state when the accelerator-off continues in a traffic jam or the like, and does not consider the above-described snap ring protrusion at all. . Therefore, even if the technique described in Patent Document 4 is used, the above-described problem cannot be solved.

  The present invention has been made in view of such a situation, and in a control device for a vehicle on which a friction engagement device having a snap ring for restricting movement of a friction engagement element is mounted, An object is to realize control capable of suppressing the protrusion of the snap ring.

  According to the present invention, a friction engagement device including a friction engagement element and a snap ring for restricting axial movement of the friction engagement element is provided in a power transmission path between an engine and a drive wheel. In the control device applied to the vehicle, the friction engagement device (clutch, brake, etc.) is operated under the condition that it is determined that the accelerator is off and the accelerator is off while the vehicle is running. It is a technical feature to be in a disengaged state.

  In this way, by disengaging the friction engagement device (specifically, the clutch / brake engaged when the vehicle travels) while the vehicle is traveling with the accelerator off (coasting traveling). Since the frictional force (the frictional force acting between the friction plate or the clutch drum or the like) and the snap ring can be released, which causes the snap ring to stick out, the snap ring can be prevented from sticking out.

  Here, if the friction engagement device is disengaged in all cases where the condition of accelerator-off (accelerator opening 0%) is satisfied during vehicle travel, the driver can instantaneously turn on / off the accelerator. If this happens, it will not be possible to follow it, which may cause problems in terms of drivability. In view of these points, in the present invention, in addition to the condition that the accelerator is off during vehicle travel, the friction engagement is performed when the condition that it is determined that travel while the accelerator is off is satisfied. The device is in a disengaged state, and with such a configuration, it is possible to suppress the protrusion of the snap ring while preventing the drivability from deteriorating.

  In a vehicle equipped with a belt-type continuously variable transmission, the safety factor of the belt clamping pressure must be maintained higher than that during driving due to the influence of engine inertia during coasting (driven). However, as in the present invention, the friction engagement device (specifically, the forward / reverse switching of the front stage of the belt-type continuously variable transmission) is performed. By disengaging the clutch and brake of the device, it is possible to reduce the influence of engine inertia during coasting. As a result, it is possible to reduce the belt clamping pressure during coasting and improve fuel efficiency.

  As a specific configuration of the present invention, a gradient sensor that detects a vehicle gradient with respect to a horizontal plane is provided, and the vehicle gradient detected by the gradient sensor is a downward gradient, and the downward gradient is equal to or greater than a determination threshold value. A configuration in which it is determined that traveling while the accelerator is off continues.

  In the present invention, when the accelerator is turned on after the friction engagement device is brought into the non-engaged state under the condition that the accelerator is off during traveling of the vehicle and the traveling with the accelerator off is determined to continue. The friction engagement device may be brought into an engaged state. With this configuration, it is possible to lengthen the period during which the friction engagement device is disengaged during coasting travel, and therefore, particularly in a vehicle equipped with a belt-type continuously variable transmission, fuel consumption can be further improved. Effectively.

  In addition, the frictional engagement device is instantaneously disengaged under the condition that the accelerator is off while the vehicle is traveling and the traveling with the accelerator off is continued, and then the frictional engagement device is engaged. You may make it make a joint state. Even if such a configuration is adopted, the frictional force that causes the snap ring to protrude can be released, so that the protrusion of the snap ring can be suppressed. In this case, “instantaneous” means a short period of time that allows the snap ring to return to its original shape due to the release of the frictional force that holds the protrusion of the snap ring.

  According to the present invention, since the friction engagement device is brought into the non-engagement state under the condition that the accelerator is off while the vehicle is traveling and the travel is performed with the accelerator off, the friction engagement device snaps. The protrusion of the ring can be suppressed.

It is a schematic structure figure showing an example of a vehicle to which the present invention is applied. It is a principal part longitudinal cross-sectional view of the forward / backward switching apparatus applied to the vehicle of FIG. It is a figure which shows an example of the map used for the shift control of a belt-type continuously variable transmission. It is a figure which shows an example of the map used for the belt clamping pressure control of a belt-type continuously variable transmission. It is a block diagram which shows the structure of control systems, such as ECU. It is a flowchart which shows an example of the frictional force release control of a snap ring. It is a schematic block diagram which shows the engine, automatic transmission, and control system which are mounted in the other example of the vehicle to which the control apparatus of this invention is applied. FIG. 8 is a partial longitudinal sectional view of the automatic transmission shown in FIG. 7. It is an operation | movement table | surface of the automatic transmission shown in FIG. It is a circuit block diagram which shows a part of hydraulic control circuit of the automatic transmission shown in FIG. It is a block diagram which shows the structure of the control system of the engine shown in FIG. 7, and an automatic transmission. It is a figure which shows an example of the shift map used for the shift control of the automatic transmission shown in FIG. It is a front view which shows an example of a snap ring typically.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[Embodiment 1]
FIG. 1 is a schematic configuration diagram showing an example of a vehicle to which the present invention is applied.

  The vehicle in this example is an FF (front engine / front drive) type vehicle, which is an engine (internal combustion engine) 1 that is a driving power source, a torque converter 2 as a fluid transmission device, a forward / reverse switching device 3, and a belt type. A continuously variable transmission (CVT) 4, a reduction gear device 5, a differential gear device 6, and an ECU 8 are mounted. The ECU 8, a hydraulic control circuit 20, a torque converter 2, and a forward / reverse switching device 3 (described later) The vehicle control device is realized by the forward clutch C1 and the reverse brake B1), the belt type continuously variable transmission 4, various sensors such as the accelerator opening sensor 107 and the gradient sensor 108 shown in FIG.

  A crankshaft 11, which is an output shaft of the engine 1, is connected to the torque converter 2, and the output of the engine 1 is transmitted from the torque converter 2 via the forward / reverse switching device 3, the belt type continuously variable transmission 4, and the reduction gear device 5. Are transmitted to the differential gear device 6 and distributed to the left and right drive wheels 7.

  The parts of the engine 1, the torque converter 2, the forward / reverse switching device 3, the belt-type continuously variable transmission 4, and the ECU 8 will be described below.

-Engine-
The engine 1 is a multi-cylinder gasoline engine, for example. The amount of intake air taken into the engine 1 is adjusted by an electronically controlled throttle valve 12. The throttle valve 12 can electronically control the throttle opening independently of the driver's accelerator pedal operation, and the opening (throttle opening) is detected by the throttle opening sensor 102. Further, the coolant temperature of the engine 1 is detected by a water temperature sensor 103.

  The throttle opening of the throttle valve 12 is driven and controlled by the ECU 8. Specifically, the optimum intake air amount (in accordance with the operating state of the engine 1 such as the engine speed Ne detected by the engine speed sensor 101 and the accelerator pedal depression amount (accelerator operation amount Acc) of the driver). The throttle opening of the throttle valve 12 is controlled so as to obtain a target intake air amount. More specifically, the actual throttle opening of the throttle valve 12 is detected using the throttle opening sensor 102, and the actual throttle opening coincides with the throttle opening (target throttle opening) at which the target intake air amount can be obtained. Thus, the throttle motor 13 of the throttle valve 12 is feedback-controlled.

-Torque converter-
The torque converter 2 includes an input-side pump impeller 21, an output-side turbine runner 22, a stator 23 that exhibits a torque amplifying function, and the like. A fluid (hydraulic oil) is provided between the pump impeller 21 and the turbine runner 22. ) To transmit power. The pump impeller 21 is connected to the crankshaft 11 of the engine 1. The turbine runner 22 is connected to the forward / reverse switching device 3 via the turbine shaft 27.

  The torque converter 2 is provided with a lockup clutch 24 that directly connects the input side and the output side of the torque converter 2. The lock-up clutch 24 controls the differential pressure (lock-up differential pressure) between the hydraulic pressure in the engagement side oil chamber 25 and the hydraulic pressure in the release side oil chamber 26 to achieve full engagement and half engagement (in the slip state). Engagement) or release.

  By completely engaging the lockup clutch 24, the pump impeller 21 and the turbine runner 22 rotate integrally. Further, by engaging the lockup clutch 24 in a predetermined slip state (half-engaged state), the turbine runner 22 rotates following the pump impeller 21 with a predetermined slip amount during driving. On the other hand, by setting the lockup differential pressure to be negative, the lockup clutch 24 is released.

  The torque converter 2 is provided with a mechanical oil pump (hydraulic pressure generating source) 10 that is connected to and driven by the pump impeller 21.

-Forward / reverse switching device-
The forward / reverse switching device 3 includes a double pinion type planetary gear mechanism 30, a forward clutch (forward clutch) C1, and a reverse brake (reverse brake) B1.

  The sun gear 31 of the planetary gear mechanism 30 is integrally connected to the turbine shaft 27 of the torque converter 2, and the carrier 33 is integrally connected to the input shaft 40 of the belt type continuously variable transmission 4. The carrier 33 and the sun gear 31 are selectively connected via a forward clutch C1. The ring gear 32 is selectively fixed to the housing 300 via the reverse brake B1.

  The forward clutch C1 and the reverse brake B1 are hydraulic friction engagement devices that are engaged / released by the hydraulic control circuit 20, and the forward clutch C1 is engaged and the reverse brake B1 is released to move forward and backward. The forward switching device 3 is integrally rotated to establish (achieve) the forward power transmission path. In this state, the forward driving force is transmitted to the belt type continuously variable transmission 4 side.

  On the other hand, when the reverse brake B1 is engaged and the forward clutch C1 is released, the forward / reverse switching device 3 establishes (achieves) a reverse power transmission path. In this state, the input shaft 40 of the belt-type continuously variable transmission 4 rotates in the reverse direction with respect to the turbine shaft 27, and the driving force in the reverse direction is transmitted to the belt-type continuously variable transmission 4 side. Further, when both the forward clutch C1 and the reverse brake B1 are released, the forward / reverse switching device 3 is in a neutral state (blocking state) that blocks power transmission.

  Next, each structure of the forward clutch C1 and the reverse brake B1 will be described with reference to FIG.

  First, the forward clutch C1 includes a friction engagement element 301 that is a clutch constituent member. The friction engagement element 301 includes a plurality of outer friction plates 311 and a plurality of inner friction plates 312 disposed between the outer friction plates 311.

  The outer friction plate 311 is fitted to a spline 310a provided on the inner diameter side of the clutch drum 310, and is movable in the axial direction. The inner friction plate 312 is spline-fitted to the outer diameter side of the friction plate support portion 33a of the carrier 33 and is movable in the axial direction.

  The spline 310a of the clutch drum 310 is provided with a snap ring 313 for restricting the axial movement of the friction engagement element 301 (movement opposite to the clutch actuator 314). For example, as shown by a solid line in FIG. 13, the snap ring 313 is processed into a C-shaped shape in which a part of the ring shape is divided, and is provided on a tooth portion (convex portion) of the spline 310 a of the clutch drum 310. It is fitted in the groove 310b.

  The clutch actuator 314 includes a clutch piston 314a, an oil chamber 314b formed between the clutch piston 314a and the clutch drum 310, a return spring (compression coil spring) 314c that urges the clutch piston 314a to the release side, and the like. It is constituted by.

  In the forward clutch C1 having the above structure, when hydraulic oil having a predetermined pressure is supplied to the oil chamber 314b, the clutch piston 314a moves toward the friction engagement element 301, and the pressing member 314A at the tip of the clutch piston 314a is frictionally applied. The engaging element 301 is pressed. When the frictional engagement element 301 is pressed in this manner, the outer friction plate 311 and the inner friction plate 312 constituting the frictional engagement element 301 are engaged with each other, and the forward clutch C1 is engaged. . On the other hand, in a state where the hydraulic oil is not supplied to the oil chamber 314b (a state where the hydraulic oil is drained), the clutch piston 314a moves in a direction away from the friction engagement element 301 by the elastic force of the return spring 314c. The clutch C1 is released.

  The reverse brake B1 includes a friction engagement element 302 that is a brake component. Similar to the forward clutch C1, the friction engagement element 302 includes a plurality of outer friction plates 321 and a plurality of inner friction plates 322 disposed between the outer friction plates 321.

  The outer friction plate 321 is fitted to a spline 300a provided on the inner diameter side of the housing 300, and is movable in the axial direction. The inner friction plate 322 is spline-fitted to the outer diameter side of the ring gear 32 and is movable in the axial direction.

  The spline 300a of the housing 300 is provided with a snap ring 323 for restricting the axial movement of the friction engagement element 302 (movement toward the side opposite to the brake actuator 324). For example, as shown by the solid line in FIG. 13, the snap ring 323 is processed into a C-shaped shape in which a part of the ring shape is divided, and a groove 300 b provided in a tooth portion (convex portion) of the spline 300 a of the housing 300. It is inserted in.

  The brake actuator 324 includes a brake piston 324a, an oil chamber 324b formed between the brake piston 324a and the housing 300, a return spring (compression coil spring) 324c that urges the brake piston 324a toward the release side, and the like. It is configured.

  In the reverse brake B1 having the above structure, when hydraulic oil having a predetermined pressure is supplied to the oil chamber 324b, the brake piston 324a moves to the friction engagement element 302 side, and the pressing member 324A at the tip of the brake piston 324a is frictionally applied. The engaging element 302 is pressed. When the friction engagement element 302 is pressed in this manner, the outer friction plate 321 and the inner friction plate 322 constituting the friction engagement element 302 are engaged with each other, and the reverse brake B1 is engaged. . On the other hand, when hydraulic oil is not supplied to the oil chamber 324b (when hydraulic oil is drained), the clutch piston 324a moves away from the friction engagement element 302 by the elastic force of the return spring 324c, and reverse The brake B1 is released.

-Belt type continuously variable transmission-
As shown in FIG. 1, the belt-type continuously variable transmission 4 includes an input-side primary pulley 41, an output-side secondary pulley 42, and a metal belt wound around the primary pulley 41 and the secondary pulley 42. 43 and the like.

  The primary pulley 41 is a variable pulley having a variable effective diameter, and a fixed sheave 411 fixed to the input shaft 40 and a movable sheave 412 disposed on the input shaft 40 in a state in which sliding is possible only in the axial direction. And is composed of. Similarly, the secondary pulley 42 is a variable pulley whose effective diameter is variable, and is a fixed sheave 421 fixed to the output shaft 44 and a movable sheave arranged on the output shaft 44 so as to be slidable only in the axial direction. 422.

  A hydraulic actuator 413 for changing the V groove width between the fixed sheave 411 and the movable sheave 412 is disposed on the movable sheave 412 side of the primary pulley 41. Similarly, a hydraulic actuator 423 for changing the V groove width between the fixed sheave 421 and the movable sheave 422 is also arranged on the movable sheave 422 side of the secondary pulley 42.

  In the belt type continuously variable transmission 4 having the above-described structure, by controlling the hydraulic pressure of the hydraulic actuator 413 of the primary pulley 41, the V groove widths of the primary pulley 41 and the secondary pulley 42 change, and the engagement diameter of the belt 43 ( The effective gear ratio) is changed, and the gear ratio γ (γ = primary pulley rotation speed (input shaft rotation speed) Nin / secondary pulley rotation speed (output shaft rotation speed) Nout) continuously changes. The hydraulic pressure of the hydraulic actuator 423 of the secondary pulley 42 is controlled such that the belt 43 is clamped with a predetermined clamping pressure that does not cause belt slip. These controls are executed by the ECU 8 and the hydraulic control circuit 20.

-Hydraulic control circuit-
As shown in FIG. 1, the hydraulic control circuit 20 engages (releases fully or half-engages) or releases the shift speed control unit 20 a, the belt clamping pressure control unit 20 b, the line pressure control unit 20 c, and the lockup clutch 24. A lock-up engagement pressure control unit 20d for controlling the clutch, a clutch pressure control unit 20e for controlling the engagement or release of the forward clutch C1 and the reverse brake B1 of the forward / reverse switching device 3, and a manual valve 20f. The clutch pressure control unit 20e is supplied with the line pressure controlled by the linear solenoid valve SLT.

  The hydraulic pressure control circuit 20 includes a shift control solenoid valve DS1 and a shift control solenoid valve DS2 for shifting speed control, a linear solenoid valve SLS for controlling belt clamping pressure, a linear solenoid valve SLT for controlling line pressure, and a lock. A duty solenoid valve DSU for up-engagement pressure control is provided. Control signals from the ECU 8 are supplied to the solenoid valves DS1, DS2, SLS, SLT, DSU.

  Then, the ECU 8 calculates the input-side target rotational speed Nint from, for example, a map shown in FIG. 3, that is, a shift map set in advance using the accelerator operation amount Acc representing the driver's output request amount and the vehicle speed V as parameters, Shift control of the belt-type continuously variable transmission 4 by controlling the shift control solenoid valves DS1 and DS2 in accordance with the deviation (Nint−Nin) so that the actual input shaft rotation speed Nin matches the target rotation speed Nint. To do. That is, under the control of the shift control solenoid valves DS1 and DS2, the shift control pressure is controlled by supplying and discharging the hydraulic oil to and from the hydraulic actuator 413 of the primary pulley 41, and the speed ratio γ continuously changes. The map in FIG. 3 corresponds to the shift conditions and is stored in the ROM 82 (see FIG. 5) of the ECU 8.

  In the map of FIG. 3, the target rotational speed Nint is set such that the larger the vehicle speed V is and the larger the accelerator operation amount Acc is, the larger the gear ratio γ is. Further, since the vehicle speed V corresponds to the secondary pulley rotational speed (output shaft rotational speed) Nout, the target rotational speed Nint, which is the target value of the primary pulley rotational speed (input shaft rotational speed) Nin, corresponds to the target gear ratio, It is set within the range of the minimum speed ratio γmin and the maximum speed ratio γmax of the continuously variable transmission 4.

  Further, the ECU 8 is set in advance so that belt slip does not occur, for example, using the map shown in FIG. 4, that is, the accelerator opening Acc and the gear ratio γ (γ = Nin / Nout) corresponding to the transmission torque. In accordance with a map of required hydraulic pressure (corresponding to belt clamping pressure), a belt type is controlled by controlling the linear solenoid valve SLS for controlling the belt clamping pressure of the hydraulic control circuit 20 and adjusting the hydraulic pressure of the hydraulic actuator 423 of the secondary pulley 42. The belt clamping pressure of the continuously variable transmission 4 is controlled. The map in FIG. 4 corresponds to the clamping pressure control condition and is stored in the ROM 82 of the ECU 8 (see FIG. 5).

-ECU-
As shown in FIG. 5, the ECU 8 includes a CPU 81, a ROM 82, a RAM 83, a backup RAM 84, and the like.

  The ROM 82 stores various control programs, maps that are referred to when the various control programs are executed, and the like. The CPU 81 executes arithmetic processing based on various control programs and maps stored in the ROM 82. The RAM 83 is a memory for temporarily storing calculation results in the CPU 81 and data input from each sensor. The backup RAM 84 is a non-volatile memory for storing data to be saved when the engine 1 is stopped. is there.

  The CPU 81, ROM 82, RAM 83, and backup RAM 84 are connected to each other via a bus 87 and are connected to an input interface 85 and an output interface 86.

  The input interface 85 includes an engine speed sensor 101, a throttle opening sensor 102, a water temperature sensor 103, a turbine speed sensor 104, a primary pulley speed sensor 105, a secondary pulley speed sensor 106, an accelerator position sensor 107, and a horizontal plane. A gradient sensor 108 that detects the vehicle gradient, a brake pedal sensor 109, and a lever position sensor 110 that detects a lever position (operation position) of the shift lever 9 are connected. Output signals of the sensors, that is, Engine 1 rotational speed (engine rotational speed) Ne, throttle valve 12 throttle opening θth, turbine shaft 27 rotational speed (turbine rotational speed) Nt, primary pulley rotational speed (input shaft rotational speed) Nin, secondary pulley rotational speed (Output shaft Rotation number) Nout, accelerator pedal operation amount (accelerator degree of engagement) Acc, vehicle gradient α, presence / absence of operation of foot brake (brake ON / OFF), and lever position of shift lever 9 (operation position) And the like are supplied to the ECU 8.

  The output interface 86 is connected to the throttle motor 13, the fuel injection device 14, the ignition device 15, the hydraulic control circuit 20, and the like.

  Here, among the signals supplied to the ECU 8, the turbine rotational speed Nt coincides with the primary pulley rotational speed (input shaft rotational speed) Nin during forward travel in which the forward clutch C1 of the forward / reverse switching device 3 is engaged, The pulley rotation speed (output shaft rotation speed) Nout corresponds to the vehicle speed V. The accelerator operation amount Acc represents the driver's requested output amount. In addition to the gradient sensor 108, the vehicle gradient α may be calculated from an output signal of another sensor such as a longitudinal acceleration sensor.

  The shift lever 9 includes a parking position “P” for parking, a reverse position “R” for reverse traveling, a neutral position “N” for interrupting power transmission, a drive position “D” for forward traveling, During forward running, the gear ratio γ of the belt type continuously variable transmission 4 is selectively operated to each position such as a manual position “M” where the manual operation can increase or decrease the speed ratio γ.

  The manual position “M” includes a plurality of ranges in which a downshift position and an upshift position for increasing / decreasing the speed ratio γ, or a plurality of speed ranges in which the upper limit of the speed range (the side where the speed ratio γ is smaller) are different can be selected. Position etc. are provided.

  The lever position sensor 110 is, for example, a parking position “P”, a reverse position “R”, a neutral position “N”, a drive position “D”, a manual position “M”, an upshift position, a downshift position, or a range position. A plurality of ON / OFF switches for detecting that the shift lever 9 is operated are provided. In order to change the gear ratio γ manually, a downshift switch, an upshift switch, or a lever can be provided on the steering wheel or the like separately from the shift lever 9.

  The ECU 8 controls the output of the engine 1, the engagement / release control of the lockup clutch 24, the forward clutch C1 and the reverse brake B1 of the reverse switching device 3 based on the output signals of the various sensors described above. The combination / release control, the above-described shift speed control of the belt-type continuously variable transmission 4, the belt clamping pressure control, and the like are executed. The output control of the engine 1 is executed by the throttle motor 13, the fuel injection device 14, the ignition device 15, the ECU 8, and the like. Further, the ECU 8 executes the following [snap ring frictional force release control].

-Friction force release control of snap ring-
First, in the vehicle of this example, as described above, the forward / reverse switching device 3 disposed in the preceding stage of the belt type continuously variable transmission 4 is provided with the forward clutch C1 and the reverse brake B1 that are friction engagement devices. The forward clutch C1 and the reverse brake B1 are provided with snap rings 313 and 323 for restricting the axial movement of the friction engagement elements 301 and 302, respectively.

  As described above, in the friction engagement device (forward clutch C1 or reverse brake B1) provided with the snap ring as described above, when positive and negative torque inputs are applied in the engaged state, the friction plate (or clutch drum, housing, etc.) is applied. ) And the snap ring, the snap ring may be pulled into the inner diameter side, and a part of the snap ring may protrude from the groove (see a two-dot chain line in FIG. 13). In particular, since the forward clutch C1 of the forward / reverse switching device 3 is kept engaged during forward travel in normal control, there is a high possibility that the protruding state of the snap ring described above will be maintained for a long time.

  In order to eliminate such a point, in this example, the accelerator is turned off while the vehicle is running, and the friction engagement device is brought into the non-engaged condition under the condition that the running with the accelerator off is continued. The control is characterized in that the protrusion of the snap ring is suppressed.

  The specific control will be described with reference to the flowchart of FIG. The control routine of FIG. 6 shows an example of control in the case where the protrusion of the snap ring 313 provided in the forward clutch C1 of the forward / reverse switching device 3 is suppressed.

  First, in step ST101, it is determined whether or not the vehicle is running based on the output shaft rotational speed Nout (vehicle speed V) calculated from the output signal of the secondary pulley rotational speed sensor 106, and the determination result is negative. If it is, return. When the determination result of step ST101 is affirmative (when the vehicle is traveling), the process proceeds to step ST102.

  In step ST102, it is determined whether the accelerator opening Acc calculated from the output signal of the accelerator opening sensor 107 is 0% (Acc = 0%), that is, whether the accelerator is off. If the determination result in step ST102 is negative, the process returns. If the determination result of step ST102 is affirmative, the process proceeds to step ST103.

  In step ST103, whether or not the vehicle gradient α calculated from the output signal of the gradient sensor 108 is a downward gradient, and the downward gradient (gradient angle) is equal to or greater than a predetermined determination threshold (downgradient ≧ determination threshold). Determine. If the determination result in step ST103 is negative, the process returns. If the determination result of step ST103 is affirmative, the process proceeds to step ST104.

  Here, step ST103 is a processing step for determining whether or not the accelerator-off travel can be continued. The determination threshold used for the determination in step ST103 is a condition for determining that the accelerator-off travel continues. The (downhill angle) is empirically obtained through experiments, calculations, etc., and a suitable value is set based on the result.

  When all of the above conditions of Step ST101, Step ST102, and Step ST103 are satisfied, that is, when it is determined that the accelerator is off and the accelerator is off while the vehicle is traveling, the hydraulic control circuit 20 (For example, the clutch pressure control unit 20e) is controlled to place the forward clutch C1 in a disengaged state (released state) (step ST104).

  Thereafter, when the accelerator opening degree Acc calculated from the output signal of the accelerator opening degree sensor 107 becomes a value larger than 0% (Acc> 0%: accelerator on) while the vehicle is traveling (determination result of step ST105). Forward clutch C1 is engaged (step ST106).

  As described above, in this example, the forward clutch C1, which is the friction engagement device, is disengaged (released) while the vehicle is traveling with the accelerator off (coasting traveling). (The friction force acting between the outer friction plate 311 or the spline 310a of the clutch drum 310 and the snap ring 313) can be released (cancelled), and the snap ring 313 can be restored by tension. The shape can be returned to. Thereby, the protrusion of the snap ring 313 can be suppressed.

  In addition, in this example, the forward clutch C1 is not disengaged in all cases where the accelerator off (accelerator opening 0%) condition is satisfied during vehicle travel, but the accelerator is off during vehicle travel. The friction engagement device is brought into a non-engagement state when there is a condition (down slope ≧ determination threshold) that is determined to exist and the accelerator is off, and the instantaneous engagement by the driver When the accelerator is turned on / off, it can be followed. As a result, the protrusion of the snap ring can be suppressed while preventing the drivability from deteriorating.

  Here, in a vehicle equipped with a belt type continuously variable transmission, it is necessary to maintain a safety factor of the belt clamping pressure higher than that during driving due to the influence of engine inertia during coasting (driven). In this example, the forward clutch C1 of the forward / reverse switching device 3 disposed in the front stage of the belt-type continuously variable transmission 4 is disengaged (in this example). Since the engine 1 and the belt-type continuously variable transmission 4 are cut off), the influence of engine inertia during coasting can be reduced. As a result, the belt clamping pressure during coasting can be reduced, and as a result, fuel consumption can be improved.

  In the above example, the forward clutch C1 of the forward / reverse switching device 3 is disengaged when the condition that it is determined that the accelerator is off during the vehicle travel (forward travel) and the travel with the accelerator off is continued. In the engaged state, the reverse brake B1 of the forward / reverse switching device 3 is in the non-engaged state when the above condition is satisfied during reverse coasting travel (when the reverse brake B1 is engaged). You may make it.

  Note that the snap ring frictional force release control described above may not be executed, for example, when there is a request for engine braking.

[Embodiment 2]
Next, another embodiment of the present invention will be described with reference to FIGS.

  In this example, a control device applied to a vehicle equipped with a stepped automatic transmission will be described. Also in this example, various types such as an ECU 1000, a hydraulic control circuit 800, a torque converter 600, an automatic transmission 700 (including a friction engagement device such as a clutch / brake), an accelerator opening sensor 926, a gradient sensor 927, and the like, which will be described later. A vehicle control device is realized by sensors and the like.

  FIG. 7 is a skeleton diagram showing an example of a stepped automatic transmission (including a torque converter). The automatic transmission 700 of this example is mounted on an FF (front engine / front drive) type vehicle.

  First, the torque converter 600 includes a pump impeller 601 on the input shaft side, a turbine runner 602 on the output shaft side, a stator 603 that expresses a torque amplification function, and a one-way clutch 604, and the pump impeller 601 and the turbine runner 602 are provided. Power is transmitted between the two through the fluid.

  The torque converter 600 is provided with a lockup clutch 605 that directly connects the input side and the output side. By completely engaging the lockup clutch 605, the pump impeller 601 and the turbine runner 602 are integrated. Rotate. Further, by engaging the lockup clutch 605 in a predetermined slip state, the turbine runner 602 rotates following the pump impeller 601 with a predetermined slip amount during driving.

  The automatic transmission 700 includes a first transmission unit 700A mainly composed of a single pinion type first planetary gear unit 701, a single pinion type second planetary gear unit 702, and a double pinion type third planetary gear unit 703. A planetary gear type multi-stage transmission (forward drive) that shifts the rotation of the input shaft 711, transmits it to the output shaft 712, and outputs it from the output gear 713. 6-speed, reverse 1-speed). The output gear 713 is directly connected to a differential gear device mounted on the vehicle or connected to the differential gear device via a counter shaft.

  Since the automatic transmission 700 and the torque converter 600 are substantially symmetrical with respect to the center line, the lower half of the center line is omitted in FIG.

  The first planetary gear device 701 constituting the first transmission unit 700A includes three rotating elements, a sun gear S1, a carrier CA1, and a ring gear R1, and the sun gear S1 is connected to the input shaft 711. Further, the sun gear S1 is decelerated and rotated with respect to the input shaft 711 using the carrier CA1 as an intermediate output member by fixing the ring gear R1 to the housing case 710 via the third brake B3.

  In the second planetary gear device 702 and the third planetary gear device 703 constituting the second transmission unit 700B, four rotating elements RM1 to RM4 are configured by being partially connected to each other.

  Specifically, the first rotating element RM1 is constituted by the sun gear S3 of the third planetary gear unit 703, and the ring gear R2 of the second planetary gear unit 702 and the ring gear R3 of the third planetary gear unit 703 are connected to each other. A second rotation element RM2 is configured. Furthermore, the carrier CA2 of the second planetary gear device 702 and the carrier CA3 of the third planetary gear device 703 are connected to each other to constitute a third rotating element RM3. The fourth rotating element RM4 is configured by the sun gear S2 of the second planetary gear device 702.

  In the second planetary gear device 702 and the third planetary gear device 703, the carriers CA2 and CA3 are configured by a common member, and the ring gears R2 and R3 are configured by a common member. Further, the pinion gear of the second planetary gear device 702 is a Ravigneaux type planetary gear train that also serves as the second pinion gear of the third planetary gear device 703.

  The first rotating element RM1 (sun gear S3) is integrally connected to the carrier CA1 of the first planetary gear device 701 as an intermediate output member, and is selectively connected to the housing case 710 by the first brake B1 for rotation. Stopped.

  The second rotation element RM2 (ring gears R2 and R3) is selectively connected to the input shaft 711 via the second clutch C2, and is selectively connected to the housing case 710 via the second brake B2 for rotation. Stopped. The second rotation element RM2 is always prevented from rotating in the reverse direction by the one-way clutch F1.

  The third rotation element RM3 (carriers CA2 and CA3) is integrally connected to the output shaft 712. The fourth rotation element RM4 (sun gear S2) is selectively coupled to the input shaft 711 via the first clutch C1.

  Next, among the components of the automatic transmission 1, the structures of the first clutch C1 and the second clutch C2 will be described with reference to FIG.

  The first clutch C <b> 1 includes a first friction engagement element 720. The first friction engagement element 720 includes a plurality of outer friction plates 721 and a plurality of inner friction plates 722 disposed between the outer friction plates 721.

  The outer friction plate 721 constituting the first friction engagement element 720 is fitted to a spline 742 processed on the inner peripheral surface of the cylindrical portion 741 of the clutch drum 740, and is movable in the axial direction. The inner friction plate 722 is splined to the outer peripheral surface of the first clutch hub 771 and is movable in the axial direction.

  The spline 742 of the clutch drum 740 is provided with a snap ring 723 for restricting movement of the first friction engagement element 720 in the axial direction (movement toward the second friction engagement element 730 side). For example, as shown by the solid line in FIG. 13, the snap ring 723 is processed into a C shape in which a part of the ring shape is divided, and a groove provided in a tooth portion (convex portion) of the spline 742 of the clutch drum 740. 743.

  The second clutch C2 includes a second friction engagement element 730. Similarly, the second friction engagement element 730 includes a plurality of outer friction plates 731 and a plurality of inner friction plates 732 disposed between the outer friction plates 731.

  The outer friction plate 731 constituting the second friction engagement element 730 is fitted to a spline 742 processed on the inner peripheral surface of the cylindrical portion 741 of the clutch drum 740, and is movable in the axial direction. The inner friction plate 732 is splined to the outer peripheral surface of the second clutch hub 772 and is movable in the axial direction.

  The spline 742 of the clutch drum 740 is provided with a snap ring 733 for restricting movement of the second friction engagement element 730 in the axial direction (movement toward the first friction engagement element 720). For example, as shown by the solid line in FIG. 13, the snap ring 733 is processed into a C-shaped shape in which a part of the ring shape is divided, and a groove provided in a tooth portion (convex portion) of the spline 742 of the clutch drum 740. 744 is fitted.

  A first piston 750 is disposed on the front side of the clutch drum 740 (first clutch C1 side). The first piston 750 is fitted to the input shaft 711 so as to be slidable in the axial direction. The first piston 750 is a substantially disk-shaped member, and a pressing member 751 is integrally formed on the outer peripheral edge. The first piston 750 rotates integrally with the clutch drum 740.

  A first oil chamber 750a is formed between the first piston 750 and the side wall 745 of the clutch drum 740. When hydraulic oil is supplied into the first oil chamber 750a, the first piston 750 is engaged with the clutch. It moves in a direction away from the drum 740 (first friction engagement element 720 side), and the pressing member 751 at the tip of the first piston 750 presses the first friction engagement element 720. When the first friction engagement element 720 is pressed in this manner, the outer friction plate 721 and the inner friction plate 722 constituting the first friction engagement element 720 are engaged with each other, and the first clutch C1 is engaged. Is engaged.

  On the other hand, in a state where hydraulic oil is not supplied to the first oil chamber 750a (a state where the hydraulic oil is drained), the first piston 750 is separated from the first friction engagement element 720 by the elastic force of a return spring 750b described later. Moving in the direction, the first clutch C1 is released.

  An annular balancer 781 is disposed on the front side (clutch C1 side) of the first piston 750. The balancer 781 is fitted on the input shaft 711, and movement in a direction away from the first piston 750 is restricted by a snap ring 783 fixed to the input shaft 711. A return spring (compression coil spring) 750b is arranged between the balancer 781 and the first piston 750, and the first piston 750 is separated from the balancer 781 by the elastic force of the return spring 750b (clutch). The drum 740 side) is biased. A cancel chamber (oil chamber) 791 for canceling the centrifugal hydraulic pressure of the first oil chamber 750a is formed between the balancer 781 and the first piston 750. The first piston 750, the first oil chamber 750a, the return spring 750b, and the like constitute a first clutch actuator.

  A second piston 760 is disposed on the back side of the clutch drum 740 (the opposite side of the first piston). The second piston 760 is fitted to the base member 740a of the clutch drum 740 so as to be slidable in the axial direction. The second piston 760 rotates integrally with the clutch drum 740.

  The second piston 760 has a cylindrical cylinder member 761 that covers the outer periphery of the clutch drum 740, an annular side wall 762 that is fitted to one end of the cylinder member 761, and the side wall 762 is fixed to the cylinder member 761. And a snap ring 763. A pressing member 763 protruding inward (rotation center side) is integrally formed at the tip (other end) of the cylinder member 761.

  A second oil chamber 760a is formed between the side wall 762 of the second piston 760 and the side wall 745 of the clutch drum 740. When hydraulic oil is supplied into the second oil chamber 760a, the second piston 760 moves in a direction away from the clutch drum 740 (the direction opposite to the first piston 750), and the pressing member 763 at the tip of the second piston 760 presses the second friction engagement element 730. When the second friction engagement element 730 is pressed in this manner, the outer friction plate 731 and the inner friction plate 732 constituting the second friction engagement element 730 are engaged with each other, and the second clutch C2 is engaged. Is engaged.

  On the other hand, in a state where the hydraulic oil is not supplied to the second oil chamber 760a (a state where the hydraulic oil is drained), the second piston 760 is separated from the second friction engagement element 730 by an elastic force of a return spring 760b described later. The second clutch C2 is disengaged by moving in the direction.

  An annular balancer 782 is disposed on the back side of the second piston 760 (opposite side of the second oil chamber 760a). The balancer 782 is fitted on the base member 740a of the clutch drum 740, and movement in a direction away from the second piston 760 is restricted by a snap ring 784 fixed to the base member 740a. A return spring (compression coil spring) 760b is disposed between the balancer 782 and the side wall 762 of the second piston 760, and the second piston 760 is separated from the balancer 782 by the elastic force of the return spring 760b. It is biased toward the clutch drum 740 side. A cancel chamber (oil chamber) 792 for canceling the centrifugal oil pressure of the second oil chamber 760a is formed between the balancer 782 and the second piston 760. The second piston 760, the second oil chamber 760a, the return spring 760b, and the like constitute a second clutch actuator.

  In the automatic transmission 2 described above, the first clutch C1, the second clutch C2, the first brake B1, the second brake B2, the third brake B3, and the one-way clutch F1, which are friction engagement elements, are in a predetermined state. The gear position is set by being engaged or released.

  FIG. 9 is an engagement table for explaining the engagement operation of the clutch and the brake for establishing each gear stage of the automatic transmission 700, where “◯” represents engagement and “×” represents release. Yes.

  As shown in FIG. 9, when the clutch C1 of the automatic transmission 700 is engaged, the first forward speed (1st) is established, and the one-way clutch F1 is engaged at the first speed. When the first clutch C1 and the brake B1 are engaged, the second forward speed (2nd) is established. When the first clutch C1 and the third brake B3 are engaged, the third forward speed (3rd) is established.

  Further, when the first clutch C1 and the second clutch C2 are engaged, the fourth forward speed (4th) is established. When the second clutch C2 and the third brake B3 are engaged, the fifth forward speed (5th) is established. When the second clutch C2 and the first brake B1 are engaged, a forward gear 6 (6th) is established. On the other hand, when the second brake B2 and the third brake B3 are engaged, a reverse speed (Rev) is established.

  As shown in FIG. 7, the rotational speed (turbine rotational speed) of the input shaft 711 of the automatic transmission 700 is detected by the input shaft rotational speed sensor 924. Further, the rotational speed of the output shaft 712 of the automatic transmission 700 is detected by an output shaft rotational speed sensor 925. The current gear position of the automatic transmission 700 can be determined based on the rotation speed ratio (output rotation speed / input rotation speed) calculated from the output signals of the input shaft rotation speed sensor 924 and the output shaft rotation speed sensor 925. it can.

  Next, a part of the hydraulic control circuit 800 of the automatic transmission 700 will be described with reference to FIG.

  The hydraulic control circuit 800 of this example includes a linear solenoid valve (SL1) 801 for controlling engagement / release of the first clutch C1, and a linear solenoid valve (SL2) for controlling engagement / release of the second clutch C1. 802, a linear solenoid valve (SL3) 803 for controlling engagement / release of the first brake B1, a linear solenoid valve (SL4) 804 for controlling engagement / release of the third brake B3, etc. I have.

  The linear solenoid valve (SL1) 801 generates a first hydraulic pressure PC1 for controlling the engagement state of the first clutch C1 using a D range pressure PD output from a manual valve (not shown) as a base pressure, and the first hydraulic pressure PC1 is output to the first oil passage 811 connected to the hydraulic servo of the first clutch C1. The linear solenoid valve (SL2) 802 generates a second hydraulic pressure PC2 for controlling the engagement state of the second clutch C2 using the D range pressure PD as a source pressure, and uses the second hydraulic pressure PC2 as the hydraulic pressure of the second clutch C2. Output to the second oil passage 812 connected to the servo.

  The linear solenoid valve (SL3) 803 generates a third hydraulic pressure PB1 for controlling the engagement state of the first brake B1 using the D range pressure PD as a source pressure, and uses the third hydraulic pressure PB1 as the hydraulic pressure of the first brake B1. Output to the third oil passage 813 connected to the servo. The linear solenoid valve (SL4) 804 generates a fourth hydraulic pressure PB3 for controlling the engagement state of the third brake B3 using the line pressure PL as a source pressure, and the fourth hydraulic pressure PB3 is used as a hydraulic servo for the third brake B3. To the fourth oil passage 814 connected to The second brake B2 is controlled by a linear solenoid valve (SLU, SL) (not shown) and a B2 control valve.

  The above-described linear solenoid valve (SL1) 801, linear solenoid valve (SL2) 802, linear solenoid valve (SL3) 803, linear solenoid valve (SL4) 804, linear solenoid valve (SLU, SL), and the like are controlled by the ECU 1000.

-ECU-
The ECU 1000 includes a CPU, a ROM, a RAM, a backup RAM, an input / output interface, and the like, like the ECU 8 shown in FIG.

  As shown in FIG. 11, the ECU 1000 includes an engine speed sensor 921, a throttle opening sensor 922, a water temperature sensor 923, an input shaft rotational speed (turbine rotational speed) sensor 924, an output shaft rotational speed sensor 925, an accelerator opening sensor. 926, a gradient sensor 927 that detects a vehicle gradient with respect to a horizontal plane, a lever position sensor 928 that detects a lever position (operation position) of a shift lever, and the like are connected, and an output signal of each sensor is input to the ECU 1000. The The ECU 1000 is connected to an engine throttle motor 911, a fuel injection device 912, an ignition device 913, a hydraulic control circuit 800, and the like.

  ECU 1000 outputs a solenoid control signal to hydraulic control circuit 800. Based on this solenoid control signal, the linear solenoid valves 801 to 804 of the hydraulic pressure control circuit 800 are controlled, and the first clutch C1 of the automatic transmission 700 is configured so as to constitute a predetermined shift gear stage (first speed to sixth speed). The second clutch C2, the first brake B1, the second brake B2, the third brake B3, the one-way clutch F1, and the like are engaged or released in a predetermined state. The ECU 1000 also executes the following [shift control] and [snap ring frictional force release control].

-Shift control-
First, a shift map used for shift control in this example will be described with reference to FIG.

  The shift map shown in FIG. 12 is a map in which a vehicle speed and an accelerator opening are used as parameters, and a plurality of areas for determining an appropriate gear stage are set according to the vehicle speed and the accelerator opening, and the ROM of the ECU 1000 Is stored within. Each region of the shift map is partitioned by a plurality of shift lines (gear stage switching lines). Note that the shift map shown in FIG. 12 shows only the upshift line.

  Next, the basic operation of the shift control will be described.

  ECU 1000 calculates the vehicle speed from the output signal of output shaft speed sensor 925, calculates the accelerator opening from the output signal of accelerator opening sensor 926, and calculates the shift map of FIG. 12 based on these vehicle speed and accelerator opening. The target gear stage is calculated with reference. Further, a current gear is determined by obtaining a ratio of the rotational speeds calculated from the output signals of the input shaft rotational speed sensor 924 and the output shaft rotational speed sensor 925 (output rotational speed / input rotational speed). It is determined whether a speed change operation is necessary by comparing with the target gear.

  If the result of the determination indicates that there is no need for gear shifting (when the current gear stage and the target gear stage are the same and the gear stage is set appropriately), a solenoid control signal (hydraulic command) is used to maintain the current gear stage. Signal) to the hydraulic control circuit 800 of the automatic transmission 700.

  On the other hand, when the current gear stage and the target gear stage are different, shift control is performed. For example, when the traveling state of the vehicle changes from a state where the gear stage of the automatic transmission 700 is traveling in the “fourth speed” state, for example, the point X changes to the point Y shown in FIG. Since the change occurs across the shift line [4 → 5], the target gear stage calculated from the shift map is “5-speed”, and the solenoid control signal (hydraulic command signal) for setting the 5-speed gear stage is automatically shifted. Output to the hydraulic control circuit 800 of the machine 700 to perform a shift (4 → 5 upshift) from the fourth gear to the fifth gear.

-Friction force release control of snap ring-
Also in this example, as in [Embodiment 1] described above, the frictional engagement device is disengaged under the condition that the accelerator is off and the travel with the accelerator off is continued during vehicle travel. Make a match.

  Specifically, as in the process of FIG. 6 described above, first, the accelerator opening Acc calculated from the output signal of the accelerator opening sensor 926 is 0% (Acc = 0%) while the vehicle is running. Further, when the gradient (downhill gradient) calculated from the output signal of the gradient sensor 927 is greater than or equal to a predetermined determination threshold value, the friction engagement device (for example, the gear position) of the automatic transmission 700 that is engaged at the current gear position. Is 1st, the first clutch C1 and the second clutch C2 in the case of the first clutch C1 and 4th (see FIG. 9) are disengaged (released). After that, when the accelerator opening Acc calculated from the output signal of the accelerator opening sensor 926 becomes a value larger than 0% (Acc> 0%: accelerator on) while the vehicle is running, the friction engagement device. The first clutch C1 and the second clutch C2 are engaged.

  Also in this example, the friction engagement device (for example, the first clutch C1, the second clutch C2, etc. of the automatic transmission 700) is disengaged while the vehicle is traveling with the accelerator off (running coasting). Thus, the frictional force (the frictional force acting between the outer friction plates 721 and 731 or the spline 742 of the clutch drum 740 and the snap ring 723 and 733) that causes the snap ring to protrude can be released (cancelled). Accordingly, the protrusion of the snap rings 723 and 733 can be suppressed.

  Also in this example, the friction engagement devices (the first clutch C1, the second clutch C2, etc.) are in the non-engaged state for all cases where the condition of accelerator off (accelerator opening 0%) is satisfied during vehicle travel. If the condition that it is determined that the accelerator is off while the vehicle is traveling and the traveling is continued with the accelerator off (down slope ≧ determination threshold) is satisfied, the friction engagement device is Since the disengaged state is established, it is possible to follow the momentary accelerator on / off operation by the driver. As a result, the protrusion of the snap ring can be suppressed while preventing the drivability from deteriorating.

  When the first brake B1, the second brake B2, and the third brake B3 are engaged during vehicle travel, it is determined that the above condition (accelerator is off and travel with the accelerator off is continued). When the condition is satisfied, the brakes B1, B2, and B3 may be disengaged.

-Other embodiments-
In the above example, the accelerator is turned on after the friction engagement device (clutch / brake) is disengaged under the condition that the accelerator is off while the vehicle is running and it is judged that the running with the accelerator off is continued. The friction engagement device is kept in the non-engaged state until the time becomes, but the present invention is not limited to this. For example, the frictional engagement device is instantaneously disengaged under the condition that the accelerator is off while the vehicle is traveling and the traveling with the accelerator off is continued, and then the frictional engagement device is engaged. You may make it be in a state. Even if such a configuration is adopted, the frictional force that causes the snap ring to protrude can be released, so that the protrusion of the snap ring can be suppressed.

  The condition for determining that the accelerator-off running (coasting running) continues may be a condition other than the condition that “the downward slope is equal to or greater than a predetermined determination threshold”. For example, the friction engagement device may be brought into a disengaged state on condition that the state of [accelerator opening = 0%] has continued for a predetermined time.

  In the above example, an example in which the present invention is applied to a control device for a vehicle equipped with a gasoline engine has been shown. However, the present invention is not limited to this, and a control device for a vehicle equipped with another engine such as a diesel engine. It is also applicable to.

  Further, the continuously variable transmission mounted on the vehicle is not limited to the belt type continuously variable transmission described above, and may be another type of continuously variable transmission such as a toroidal continuously variable transmission.

  The control device of the present invention is not limited to an FF (front engine / front drive) type vehicle, but can also be applied to an FR (front engine / rear drive) type vehicle and a four-wheel drive vehicle.

  The present invention can be used for control of a vehicle in which a friction engagement device is provided in a power transmission path between an engine (internal combustion engine) and a drive wheel. More specifically, the movement of the friction engagement element is regulated. The present invention can be used to control a vehicle on which a friction engagement device having a snap ring is mounted.

DESCRIPTION OF SYMBOLS 1 Engine 2 Torque converter 3 Forward / reverse switching device C1 Forward clutch (friction engagement device)
B1 Reverse brake (friction engagement device)
4 Belt type continuously variable transmission 106 Secondary pulley rotational speed sensor 107 Accelerator opening sensor 108 Gradient sensor 20 Hydraulic control circuit 20e Clutch pressure control unit SLT Linear solenoid valve 8 ECU

Claims (4)

A friction engagement device including a friction engagement element and a snap ring for restricting axial movement of the friction engagement element is provided in a vehicle provided in a power transmission path between an engine and a drive wheel. In the applied control device,
A vehicle control device characterized in that the friction engagement device is brought into a non-engagement state under conditions where it is determined that the accelerator is off and the vehicle is running with the accelerator off while the vehicle is running. The vehicle control device according to claim 1,
A slope sensor that detects a slope of the vehicle with respect to a horizontal plane, wherein the slope detected by the slope sensor is a downward slope, and when the downward slope is equal to or greater than a determination threshold, it is determined that traveling with the accelerator off continues. A vehicle control device characterized by the above. The vehicle control device according to claim 1 or 2,
When the accelerator is turned on after the friction engagement device is disengaged under the condition that it is determined that the accelerator is off and the travel with the accelerator off is continued while the vehicle is running. A control device for a vehicle, wherein the engaging device is brought into an engaged state. The vehicle control device according to claim 1 or 2,
While the vehicle is traveling, the friction engagement device is instantaneously disengaged under the condition that the accelerator is off and the travel with the accelerator off is determined to continue, and then the friction engagement device is engaged. A control apparatus for a vehicle, characterized in that the vehicle is in a combined state.

Images