JP2019078385A - Vehicular drive device - Google Patents

Abstract

To provide a vehicular drive device that comprises a belt type continuously variable transmission mechanism, and when executing control that primary pulley pressure defining a maximum transmission ratio in stopping is lower than that in traveling, can prevent belt slip in starting even in a case of falling into a stall state.SOLUTION: A control unit is configured to: when a secondary pulley stops rotating in a state where a transmission ratio of a continuously variable transmission mechanism is set to a maximum transmission ratio (t1), be able to execute a low pressure mode of supplying second oil pressure Pp2 to a primary side hydraulic oil chamber (t2), wherein the second oil pressure is lower than first oil pressure Pp1 defining the maximum transmission ratio in traveling; during execution of the low pressure mode, determine cancel conditions containing a condition that torque equal to or more than predetermined torque is transmitted from a drive source to a primary pulley (t2 to t8); and when it is determined that the cancel conditions are established, supply to the primary side hydraulic oil chamber third oil pressure Pp3 higher than the second oil pressure Pp2 (t8).SELECTED DRAWING: Figure 4

Description

  The present disclosure relates to a vehicle drive device provided with a continuously variable transmission mechanism mounted on a vehicle such as an automobile.

  Conventionally, for example, as a vehicle drive device suitable for use in a vehicle, a primary pulley, a secondary pulley, and a metal belt wound around these pulleys are provided, and the belt is continuously variable by changing the effective diameter of the pulleys. A drive device for a vehicle using a continuous variable transmission mechanism is in widespread use. In such a belt-type continuously variable transmission mechanism, the secondary pulley pressure for setting the belt clamping pressure is supplied to the hydraulic servo for pressing and controlling the movable sheave of the secondary pulley, and the gear ratio for hydraulic servo for pressing and controlling the movable sheave of the primary pulley Primary pulley pressure is supplied to set In a drive device for a vehicle using such a belt-type continuously variable transmission mechanism, belt slippage is caused by the action of a larger inner inertia shuttle than expected when a high belt clamping pressure is generated during sudden braking or the like. This can cause the hardware to wear excessively. In order to prevent such belt slippage, there is known a vehicle drive device that reduces the belt clamping pressure when belt slippage is likely to occur during sudden braking or the like (see Patent Document 1). .

  In this belt-type continuously variable transmission mechanism, the hydraulic servo for pressing the movable sheave of the primary pulley is controlled by a substantially bottomed cylindrical fixed side member fixed to the primary shaft, and the movable side provided on the back of the movable sheave The fixed side member and the movable side member form a working oil chamber capable of supplying and discharging a primary pulley pressure. Then, in this belt type continuously variable transmission mechanism, when forming the maximum gear ratio on the low speed side, the primary pulley pressure is reduced to move the movable sheave of the primary pulley toward the stationary side member, and the effective diameter of the pulley is set. Make it smaller. At this time, the tip of the movable side member of the movable sheave and the bottom portion of the fixed side member abut in the axial direction, and the movable sheave is axially positioned in a state of forming the maximum gear ratio.

JP, 2014-199117, A

  Here, in the belt type continuously variable transmission mechanism described in Patent Document 1, the maximum gear ratio can be formed regardless of the primary pulley pressure by the movable side member and the fixed side member of the movable sheave being in axial contact with each other. Therefore, when the vehicle is stopped by a foot brake or the like in the travel range, it is possible to supply an oil pressure lower than the oil pressure forming the maximum gear ratio at the time of traveling to the hydraulic oil chamber as the primary pulley pressure. The fuel efficiency can be improved by reducing the primary pulley pressure at the time of such a stop.

  However, in the vehicle drive device described in Patent Document 1, if a hydraulic pressure lower than the hydraulic pressure for forming the maximum gear ratio during traveling is supplied as the primary pulley pressure at the time of stopping, for example, the accelerator pedal is depressed while the foot brake is depressed. In the case of a so-called stall state where the driver steps on the belt, each pulley of the belt-type continuously variable transmission mechanism slightly rotates due to the occurrence of slight torsion or rattling in the power transmission system, and the belt moves to the outer peripheral side in the primary pulley As a result, there is a possibility that the transmission ratio becomes smaller than the maximum transmission ratio and slightly upshifts. In this case, when the primary pulley pressure for forming the maximum gear ratio is supplied to the hydraulic oil chamber at the time of start-up, the belt-type continuously variable transmission mechanism actually upshifts to form a gear ratio slightly smaller than the maximum gear ratio. Since the torque capacity of the primary pulley is insufficient at the time of start-up, there is a possibility that belt slippage may occur because the belt can not be held.

  Therefore, in the case where a belt type continuously variable transmission mechanism is provided and control is performed to lower the primary pulley pressure forming the maximum gear ratio at the time of stopping to a lower pressure than at the time of traveling, belt slippage at the start can be prevented even in the stalled state. It aims at providing a drive for vehicles.

  A vehicle drive device according to the present disclosure includes: a first pulley having a first fixed sheave and a first movable sheave; a second pulley having a second fixed sheave and a second movable sheave; A belt wound around the first pulley and the second pulley, and a first hydraulic oil chamber for pressingly controlling the first movable sheave by supplying a first pulley pressure to set a gear ratio And a second hydraulic oil chamber for pressing and controlling the second movable sheave by supplying a second pulley pressure to set a belt clamping pressure, and the first movable sheave engaged in a rotational direction And a first hydraulic fluid chamber formed between the first movable fluid sheave and the first movable fluid sheave, the first movable fluid sheave being fixed in the axial direction with respect to the rotational shaft. A pressure receiving member, and the first movable sheave is at the time of formation of a maximum gear ratio A continuously variable transmission mechanism in which movement in a direction away from the first stationary sheave in the axial direction is restricted, a pressure adjustment unit adjusting the first pulley pressure, and a control signal to the pressure adjustment unit The transmission control of the continuously variable transmission mechanism is performed by transmitting and when the rotation of the second pulley is stopped in a state where the transmission ratio of the continuously variable transmission mechanism is set to the maximum transmission ratio, A control unit capable of executing a low pressure mode for supplying a second hydraulic pressure lower than a first hydraulic pressure for forming the maximum speed change ratio to the first hydraulic fluid chamber; During execution of the low pressure mode, a release condition including transmission of torque equal to or greater than a predetermined torque from the drive source to the first pulley is determined, and when it is determined that the release condition is satisfied, the second hydraulic pressure The third hydraulic pressure higher than the first hydraulic oil chamber Supplies.

  According to the vehicle drive device, the control unit determines the release condition including the transmission of the torque equal to or more than the predetermined torque from the drive source to the first pulley during execution of the low pressure mode at the time of stopping, It is determined whether it has become. Then, when it is determined that the release condition is satisfied, the control unit supplies a third hydraulic pressure higher than the second hydraulic pressure to the first hydraulic oil chamber. As a result, the third hydraulic pressure higher than the second hydraulic pressure can be supplied before the continuously variable transmission mechanism in the low pressure mode generates an upshift. Even if a stall condition occurs during execution of the low pressure mode in which the pulley pressure is lower than that during traveling, belt slippage at the time of start can be prevented.

FIG. 1 is a schematic view showing a skeleton of an automatic transmission according to an embodiment. FIG. 2 is a schematic control block diagram of an automatic transmission according to the embodiment. It is a flow chart which shows the processing procedure of the automatic transmission concerning an embodiment. It is a time chart which shows the processing procedure of the automatic transmission concerning an embodiment.

  Hereinafter, the vehicle drive device according to the present embodiment will be described with reference to FIGS. 1 to 4. In the present embodiment, the case where the vehicle drive system is applied to, for example, an automobile, and applied to the automatic transmission 1 having an internal combustion engine as a drive source is described. Further, in the present embodiment, the automatic transmission 1 is of the so-called FF (front engine / front drive) type. However, the automatic transmission 1 is not limited to the FF type, and may be an FR (front engine rear drive) type.

  As shown in FIG. 1, the automatic transmission 1 includes a torque converter (fluid transmission device) 6 incorporating a lockup clutch 5, a forward / reverse switching device 3, a continuously variable transmission mechanism 2, a countershaft 7, and a differential And an apparatus 9 which is housed in an integrated divided case (not shown).

  The torque converter 6 includes a pump impeller 11 connected to the output shaft 10 of the internal combustion engine (drive source) 8 through a front cover 17, a turbine runner 13 connected to the intermediate shaft 12, and a one-way clutch 15. The lockup clutch 5 is interposed between the intermediate shaft 12 and the front cover 17. A mechanical oil pump 21 is connected to the pump impeller 11. The torque converter 6 is interposed between the internal combustion engine 8 and a primary pulley 26 described later.

  The forward / reverse switching device 3 has a double pinion planetary gear 50, a reverse brake B1, and a forward clutch C1. In the double pinion planetary gear 50, the sun gear S is connected to the intermediate shaft 12, and the carrier CR supporting the first and second pinions P1 and P2 is attached to the stationary sheave 23 on the primary side of the continuously variable transmission mechanism 2 described later. The ring gear R is connected to the reverse brake B1, and the forward clutch C1 is interposed between the carrier CR and the ring gear R.

  The continuously variable transmission mechanism 2 includes a primary pulley (first pulley) 26 to which rotation from the internal combustion engine 8 can be transmitted, a secondary pulley (second pulley) 31 capable of transmitting rotation to wheels (not shown), and a primary And a metal belt 32 wound around the pulley 26 and the secondary pulley 31. The primary pulley 26 is axially slidable on the fixed sheave (first fixed sheave) 23 fixed to the primary shaft (rotational shaft) 22 and the primary shaft 22 and engaged by splines or the like in the rotational direction and supported And a movable sheave (first movable sheave) 25. Secondary pulley 31 is a stationary sheave (second stationary sheave) 29 fixed to secondary shaft 27 and a movable sheave axially slidable with secondary shaft 27 and supported by spline engagement in the rotational direction. And (second movable sheave) 30.

  The continuously variable transmission mechanism 2 has a primary hydraulic servo 33 disposed on the back of the movable sheave 25 on the primary side and a secondary hydraulic servo 35 disposed on the back of the movable sheave 30 on the secondary. The primary hydraulic servo 33 has a bottomed cylindrical fixed side member (pressure receiving member) 36 fixed to the primary shaft 22 and a cylindrical movable side member 39 fixed to the back of the movable sheave 25 The stationary side member 36 and the movable side member 39 constitute a primary side hydraulic fluid chamber (first hydraulic fluid chamber) 41. The primary side hydraulic fluid chamber 41 controls the pressure of the movable sheave 25 to set the transmission gear ratio by being supplied with the primary pulley pressure (first pulley pressure). The movable sheave 25 abuts against the fixed side member 36 at the time of formation of the maximum gear ratio, and movement in a direction away in the axial direction is restricted and positioned. Therefore, when forming the maximum gear ratio, the primary pulley pressure can be set to the second hydraulic pressure Pp2 that is lower than the first hydraulic pressure Pp1 for forming the maximum gear ratio during traveling (see FIG. 4).

  The secondary hydraulic servo 35 has a bottomed cylindrical fixed side member 43 fixed to the secondary shaft 27 and a cylindrical movable side member 45 fixed to the back of the movable sheave 30, and these fixed A secondary side hydraulic fluid chamber (second hydraulic fluid chamber) 46 is constituted by the side member 43 and the movable side member 45, and a spring 47 for preloading is provided between the movable sheave 30 and the stationary side member 43 by compression. ing. The secondary side hydraulic fluid chamber 46 controls the pressure of the movable sheave 30 to set the belt clamping pressure by being supplied with the secondary pulley pressure (second pulley pressure). The continuously variable transmission mechanism 2 can change the gear ratio continuously while drivingly connecting the internal combustion engine 8 and the wheels.

  A large gear 51 and a small gear 52 are fixed to the countershaft 7, the large gear 51 meshes with a gear 53 fixed to the secondary shaft 27, and the small gear 52 meshes with a gear 55 of the differential gear 9. ing. Differential device 9 transmits the rotation of differential gear 56 supported by differential case 66 having gear 55 to left and right axles 60 and 61 via left and right side gears 57 and 59. The left and right axles 60 and 61 are connected to wheels (not shown). Therefore, the secondary pulley 31 is drivably connected to the wheel via the differential device 9, and the rotation of the secondary pulley 31 can be stopped by a not-shown foot brake (brake device) capable of stopping the rotation of the wheel.

  Next, a control system of the automatic transmission 1 will be described. As shown in FIG. 2, a control system 20 that integrates and controls the automatic transmission 1 and the internal combustion engine 8 includes an electronic control unit (ECU) 70 and a hydraulic device (hydraulic circuit) 81. The ECU 70 is, for example, a microcomputer having a CPU, a ROM for storing a processing program, a RAM for temporarily storing data, and an input / output port. The ECU 70 includes, for example, an engine rotational speed sensor 71, a turbine rotational speed sensor 72, an input shaft rotational speed sensor 73, an output shaft rotational speed sensor 74, a throttle sensor 75, an accelerator opening sensor 76, a foot brake switch 77, and a lever position sensor 79. Etc. are connected, and signals from these various sensors and switches are input.

  The ECU 70 determines and calculates the driver's request torque, the vehicle condition, and the road condition based on the signals from the sensors, and calculates the engine operation unit 80 having a throttle actuator, a fuel injection device, an ignition device, etc. It outputs to a hydraulic device 81 having a unit 82, a transmission control unit 83, an engagement control unit 85, and the like. The ECU 70 includes a belt clamping pressure setting unit 86, a shift setting unit 87, a shift position determination unit 89, and the like.

  The belt clamping pressure setting means 86 calculates in advance the appropriate belt clamping pressure using the accelerator opening degree, the gear ratio and the input torque as parameters, and outputs an accelerator opening degree sensor 76, an input shaft rotational speed sensor 73 and a vehicle speed sensor The belt clamping pressure is set based on the actual gear ratio calculated by the shaft rotational speed sensor 74. Then, the belt clamping pressure control signal is output to the clamping pressure control unit 82 of the hydraulic device 81. The shift setting means 87 stores in advance a shift map in which the drivability and fuel efficiency of the vehicle are compatible in the relationship between the vehicle speed and the target input rotational speed of the continuously variable transmission mechanism 2 using the accelerator opening as a parameter. The target input rotational speed of the primary shaft 22 is set based on the actual vehicle speed from the output shaft rotational speed sensor 74 and the vehicle state (requested torque) from the accelerator opening degree sensor 76. Then, a shift control signal corresponding to the difference between the target input rotational speed and the actual input rotational speed from the input shaft rotational speed sensor 73 is output to the transmission control unit 83 of the hydraulic device 81 so that the target input rotational speed matches the actual input rotational speed from the input shaft rotational speed sensor 73. . The shift position determination means 89 determines each position such as P, R, D, etc. based on the signal from the lever position sensor 79 and outputs the determination signal to the engagement control unit 85 of the hydraulic device 81.

  The hydraulic device 81 includes a valve body (V / B), and includes, for example, a holding pressure control unit 82, a transmission control unit (pressure adjustment unit) 83, and an engagement control unit 85. The clamping pressure control unit 82 includes a primary regulator valve that outputs a line pressure according to the load (transmission) torque by the throttle sensor 75 or the like, and a linear solenoid valve that regulates the line pressure to generate a belt clamping pressure. There is. The belt clamping pressure output from the clamping pressure control unit 82 is supplied to the secondary hydraulic servo 35. The shift control unit 83 has a ratio control valve for controlling the transmission ratio of the continuously variable transmission mechanism 2, an upshift solenoid valve for operation thereof, a downshift solenoid valve, and the like. The hydraulic pressure adjusted and output by the transmission control unit 83 is supplied to the primary-side hydraulic servo 33 as a primary pulley pressure. The engagement control unit 85 has a manual valve or the like that is operated based on a signal from the lever position sensor 79. The hydraulic pressure output from the engagement control unit 85 is supplied to the hydraulic servo of the forward clutch C1 or the hydraulic servo of the reverse brake B1.

  Therefore, in the automatic transmission 1, the D position or the R range is determined by the shift position determination means by the driver's operation of the shift lever, and the engagement control unit 85 determines each hydraulic pressure of the forward clutch C1 or reverse brake B1. An engagement pressure is selectively supplied to the servo. The rotation transmitted from the internal combustion engine 8 to the intermediate shaft 12 via the torque converter 6 by the engagement of the forward clutch C1 is rotated forward to the primary shaft 22 of the continuously variable transmission mechanism 2 by the forward / reverse switching device 3 that rotates integrally. It is transmitted as By the engagement of the reverse brake B1, the rotation of the intermediate shaft 12 is decelerated and reversely rotated by the forward / reverse switching device 3 and transmitted to the primary shaft 22 of the continuously variable transmission mechanism 2.

  The continuously variable transmission mechanism 2 outputs a shift control signal corresponding to the target gear ratio set by the shift setting unit 87 to the shift control unit 83, and a predetermined flow rate is supplied from the shift control unit 83 to the primary hydraulic servo 33. And the effective diameter of the primary pulley 26 is manipulated. Further, the belt clamping pressure setting means 86 sets an appropriate belt clamping pressure so as not to cause a belt slip by the required transmission (request) torque and the actual gear ratio, and the clamping pressure control unit 82 A predetermined belt holding pressure is output and supplied to the secondary hydraulic servo. As a result, in the continuously variable transmission mechanism 2, in the state where an appropriate belt clamping pressure is applied from the secondary pulley 31 so that belt slip does not occur, in the primary pulley 26, the actual gear ratio matches the target gear ratio. Feedback control is performed to control the speed change steplessly.

  Next, an outline of the operation of the ECU 70 of the present embodiment will be described. The ECU 70 performs transmission control of the continuously variable transmission mechanism 2 by transmitting a control signal to the transmission control unit 83. The ECU 70 forms the maximum gear ratio during traveling when the secondary pulley 31 stops while the traveling range is selected by the shift lever and the gear ratio of the continuously variable transmission mechanism 2 is set to the maximum gear ratio. It is possible to execute a low pressure mode in which the primary hydraulic fluid chamber 41 is supplied with a second hydraulic pressure Pp2 lower than the first hydraulic pressure Pp1. The case where the rotation of the secondary pulley 31 is stopped includes, for example, the case where the vehicle is stopped by the operation of a foot brake, a hand brake or the like, or the case where the vehicle can not travel on a steep slope.

  Further, the ECU 70 determines a release condition including transmission of torque equal to or greater than a predetermined torque from the internal combustion engine 8 to the primary pulley 26 during execution of the low pressure mode. Here, when torque equal to or greater than a predetermined torque is transmitted from the internal combustion engine 8 to the primary pulley 26, for example, a so-called stall in which the accelerator opening degree is made larger than the predetermined opening degree while maintaining the stopped state by the operation of the brake device. It may be in a state. In such a stalled state, the internal combustion engine 8 outputs torque capable of normal travel (for example, an accelerator opening of about 35% or more), but the brake device transmits the continuously variable transmission mechanism 2 and forward / backward switching device from the wheels. 3 is in a state where the rotation is stopped. Therefore, the driving force from the internal combustion engine 8 is not transmitted to the wheel side when the torque converter 6 has a speed ratio of zero. However, when torque equal to or greater than a predetermined torque is transmitted from the internal combustion engine 8 to the primary pulley 26, the torsion of the shaft member in the power transmission system from the torque converter 6 to the wheels, gears, splines, etc. are relatively large. There is a possibility that rattling occurs, and there is a possibility that the pulleys 26 and 31 of the stepless transmission 2 slightly rotate due to their accumulation, and the belt 32 moves to the outer peripheral side in the primary pulley 26 and the gear ratio is maximum There is a possibility that it becomes smaller than the transmission ratio and slightly upshifts. In this case, if the primary pulley pressure for forming the maximum gear ratio is supplied to the primary side hydraulic oil chamber 41 at the time of start-up, the continuously variable transmission mechanism 2 is actually upshifted and the gear ratio slightly smaller than the maximum gear ratio. Because the torque capacity of the primary pulley 26 is insufficient at the time of start-up, the belt 32 can not be held, which may cause belt slippage.

  Therefore, in the automatic transmission 1 of the present embodiment, when the ECU 70 determines that the release condition is satisfied, the ECU 70 executes the release mode for releasing the low pressure mode, and in the release mode, the second hydraulic pressure Pp2 is higher than the second hydraulic pressure Pp2. For example, the first hydraulic pressure Pp1 is supplied to the primary side hydraulic oil chamber 41 as the third hydraulic pressure Pp3. In the automatic transmission 1 of the present embodiment, in particular, the ECU 70 supplies the first hydraulic pressure Pp1 to the primary-side hydraulic oil chamber 41 in the release mode. Therefore, the release mode is executed when the engine is in the stalled state during the low pressure mode while the vehicle is stopped, and the low pressure mode is released and the primary pulley pressure is higher than the second oil pressure Pp2 of low pressure. The pressure is increased to Pp1 (see FIG. 4). In the release mode, the primary pulley pressure supplied when the accelerator opening is zero, that is, the base pressure of the primary pulley pressure is increased to the first hydraulic pressure Pp1. Since the first oil pressure Pp1 is higher than the second oil pressure Pp2 at the time of execution of the low pressure mode, the second oil pressure is generated before the continuously variable transmission mechanism in the low pressure mode generates an upshift due to a stall state. A hydraulic pressure higher than Pp2 can be supplied. Therefore, it is possible to prevent the belt slippage at the time of start-up even if a stall state occurs during execution of the low pressure mode in which the primary pulley pressure forming the maximum gear ratio is made lower when traveling.

  Next, a specific processing procedure of the ECU 70 will be described in detail along the flowchart shown in FIG. 3 and the time chart shown in FIG. Here, there will be described a case where the vehicle on which the automatic transmission 1 is mounted is traveling, and the vehicle is re-started after the vehicle is stopped by stepping on the foot brake. In FIG. 4, the primary pulley pressure indicates a command value output from the ECU 70. Further, in this case, the accelerator opening degree is synonymous with the throttle opening degree. Moreover, although the case of a forward range is demonstrated below, the same may be said of the case of a reverse range.

  First, in the running state, it is assumed that the accelerator opening is 0 and the foot brake is depressed (t0 in FIG. 4). The vehicle speed is gradually reduced, and the primary pulley pressure is gradually reduced to gradually increase the transmission ratio of the continuously variable transmission mechanism 2 toward the maximum transmission ratio. Here, before the vehicle speed becomes 0, the maximum gear ratio is formed, and the primary pulley pressure (base pressure) at that time is set as the first hydraulic pressure Pp1 (t0 to t1 in FIG. 4). Then, the vehicle stops (step S1 in FIG. 3, t1 in FIG. 4).

  The ECU 70 determines whether the vehicle speed is 0 (stopping) and the target gear ratio is set to the maximum gear ratio (step S2 in FIG. 3). When the ECU 70 determines that the vehicle speed is not zero or the target gear ratio is not set to the maximum gear ratio, the process ends. When the ECU 70 determines that the vehicle speed is 0 and the target gear ratio is set to the maximum gear ratio, the ECU 70 executes the low pressure mode to set the base pressure of the primary pulley pressure from the first oil pressure Pp1 to the second oil pressure Pp1. The pressure is reduced to the hydraulic pressure Pp2 (step S3 in FIG. 3, t2 in FIG. 4). By executing the low pressure mode, it is possible to improve the fuel consumption while the vehicle is stopped. The dotted line in FIG. 4 indicates the primary pulley pressure when the low pressure mode is not performed. In this case, the base pressure of the primary pulley pressure is maintained at the first hydraulic pressure Pp1.

  The ECU 70 determines whether the vehicle speed is 0 (stopping) (step S4 in FIG. 3). The ECU 70 determines whether or not the vehicle speed is 0 based on the detection value of the output shaft rotational speed sensor 74. For example, if the vehicle speed is 2 km / h or less, it is determined that the vehicle is at a stop. If the ECU 70 determines that the vehicle speed is not 0 (2 km / hour or less), it assumes that the vehicle has started, cancels the low pressure mode, and stops the present process.

  If the ECU 70 determines that the vehicle speed is 0 (2 km / hour or less), the ECU 70 determines whether a release condition is satisfied (step S5 in FIG. 3). In the present embodiment, the release condition is that the accelerator opening (engine load signal) of 35% (first threshold) or more is intermittently detected twice (predetermined number of times) during execution of the low pressure mode, or The accelerator opening (engine load signal) of 35% (second threshold) or more is continuously detected for 5 seconds (predetermined time). Thus, the ECU 70 determines, based on the detection value of the accelerator opening sensor 76, whether the release condition is satisfied. If the ECU 70 determines that the release condition is not satisfied, the execution of the low pressure mode is continued (step S3 in FIG. 3, t2 to t7 in FIG. 4).

  Here, an example in the case where the accelerator opening degree of 35% or more is intermittently detected twice will be described. For example, after the low pressure mode is being executed, it is first detected that the accelerator opening is 35% or more, and then counted as the first detection when the accelerator opening falls to 30% or less. Then, when the accelerator opening which has become 30% or less becomes 35% or more again and becomes 30% or less again, it is counted as the second detection, and it is determined that the release condition is satisfied. In this case, after the first detection count, not only includes the case where the accelerator opening decreases to 0%, but also includes the case where it decreases to, for example, 29% other than 0% and then rises again to 35%. Also, after the first detection count, the accelerator opening degree not only includes the case where it immediately rises again to 35% or more, but also includes, for example, the case where it rises to 35% or more after several minutes.

  In the present embodiment, for example, when the accelerator pedal is depressed, the primary pulley pressure increases from the second hydraulic pressure Pp2 of the base pressure according to the accelerator opening degree (t3 in FIG. 4). As shown by the dotted line in FIG. 4, when the low pressure mode is not performed, the primary pulley pressure is increased from the first oil pressure Pp1 of the base pressure according to the accelerator opening degree. Then, in the present embodiment, when the accelerator opening exceeds 35%, the ECU 70 detects that the accelerator opening is 35% or more (t4 in FIG. 4). Thereafter, when the accelerator pedal is released, the accelerator opening degree decreases to 30% or less, and the primary pulley pressure decreases and returns to the second oil pressure Pp2 of the base pressure (t5 in FIG. 4). At this time, the ECU 70 counts as the first detection. Then, when the accelerator pedal is depressed again, the primary pulley pressure increases from the second hydraulic pressure Pp2 of the base pressure according to the accelerator opening degree (t6 in FIG. 4). When the accelerator opening exceeds 35% again, the ECU 70 detects that the accelerator opening is 35% or more (t7 in FIG. 4). Thereafter, when the accelerator pedal is released and the accelerator opening decreases to 30% or less, the ECU 70 counts as the second detection (t8 in FIG. 4).

  Therefore, the ECU 70 determines that the release condition is satisfied when the accelerator opening degree of 35% or more is detected twice, executes the release mode, and the base pressure of the primary pulley pressure from the second hydraulic pressure Pp2 The pressure is increased to a high third hydraulic pressure Pp3, for example, the first hydraulic pressure Pp1 (step S6 in FIG. 3, t8 in FIG. 4). In the present embodiment, the third hydraulic pressure Pp3 higher than the second hydraulic pressure Pp2 is the first hydraulic pressure Pp1, that is, the hydraulic pressure for forming the maximum gear ratio during traveling. The third hydraulic pressure Pp3 higher than the second hydraulic pressure Pp2 may be, for example, a hydraulic pressure about the primary pulley pressure supplied to the primary-side hydraulic fluid chamber 41 at the time of creep. Since the accelerator pedal is released, the primary pulley pressure is reduced to return to the first oil pressure Pp1 of the base pressure (t8 in FIG. 4). In the present embodiment, the third hydraulic pressure Pp3 higher than the second hydraulic pressure Pp2 is equal to the first hydraulic pressure Pp1. However, the present invention is not limited to this, and the third hydraulic pressure Pp3 is the second hydraulic pressure Pp2. It is good if it is higher pressure. When the third hydraulic pressure Pp3 is smaller than the first hydraulic pressure Pp1, by suppressing an increase in primary pulley pressure, good fuel consumption can be maintained while preventing belt slippage at the time of start.

  The ECU 70 determines whether depression of the accelerator pedal (accelerator on) and release of the foot brake (brake off) are detected (step S7 in FIG. 3). When the ECU 70 determines that the depression of the accelerator pedal is not detected or the release of the foot brake is not detected, the execution of the release mode is continued (step S6 in FIG. 3, t8 to t9 in FIG. 4). If the ECU 70 determines that depression of the accelerator pedal and release of the foot brake have been detected, the release mode is released and the primary pulley pressure increases from the first hydraulic pressure Pp1 of the base pressure according to the accelerator opening degree. Start (step S8 in FIG. 3, t9 in FIG. 4). At this time, since the first hydraulic pressure Pp1 having a pressure higher than the second hydraulic pressure Pp2 is supplied before the continuously variable transmission mechanism 2 in the low pressure mode generates an upshift, the vehicle is continuously variable with the continuously variable transmission mechanism 2. It is possible to start without causing belt slippage.

  As described above, according to the automatic transmission 1 of the present embodiment, the ECU 70 includes transmission of torque of a predetermined torque or more from the internal combustion engine 8 to the primary pulley 26 during execution of the low pressure mode at the time of stopping. A release condition is determined, and it is determined whether or not a stall state has occurred. Then, when it is determined that the release condition is satisfied, the ECU 70 executes the release mode for releasing the low pressure mode, and supplies the first hydraulic pressure Pp1 higher than the second hydraulic pressure Pp2 to the primary side hydraulic oil chamber 41. . Thus, since the hydraulic pressure higher than the second hydraulic pressure Pp2 can be supplied before the continuously variable transmission mechanism 2 in the low pressure mode generates an upshift, the primary pulley pressure that forms the maximum gear ratio at the time of stopping is determined. Even if a stall condition occurs during execution of the low pressure mode in which the pressure is lower than when traveling, it is possible to prevent belt slippage at the time of start.

  Further, according to the automatic transmission 1 of the present embodiment, in the release mode, the first hydraulic pressure Pp1 is supplied as the third hydraulic pressure Pp3 higher than the second hydraulic pressure Pp2. Therefore, it is possible to reliably prevent belt slippage at the time of start, and when the brake is turned off to start, it is possible to drive by supplying the same primary pulley pressure as at the time of normal travel.

  Further, according to the continuously variable transmission mechanism 2 of the present embodiment, the first pulley is the primary pulley 26 and the second pulley is the secondary pulley 31. Here, the primary pulley 26 drivingly connected to the internal combustion engine 8 in the power transmission path is more likely to receive a torque of a predetermined torque or more from the internal combustion engine 8 than the secondary pulley 31 drivingly connected to the wheel, generating belt slippage. It's easy to do. For this reason, since it is possible to prevent belt slippage in the primary pulley 26 which is more likely to cause belt slippage than the secondary pulley 31, belt slippage of the continuously variable transmission mechanism 2 can be suppressed more effectively.

  In the automatic transmission 1 of the present embodiment described above, the release condition for executing the release mode is a case where the accelerator opening degree greater than the first opening degree is intermittently detected a predetermined number of times during execution of the low pressure mode. Although the case where the first opening degree is 35% and the predetermined number of times is twice has been described, the present invention is not limited thereto. For example, the first opening degree can be appropriately set to 30 to 40% of the accelerator opening degree (or the throttle opening degree), and the predetermined number of times can be appropriately set to about 1 to 3 times. Further, as the release condition for executing the release mode, the accelerator opening degree greater than the second opening degree may be continuously detected for a predetermined time during execution of the low pressure mode, and in this case, for example, The opening degree 2 can be 35%, and the predetermined time can be 5 seconds. However, also in this case, for example, the accelerator opening (or the throttle opening) can be appropriately set to 30 to 40% as the second opening, and to approximately 3 to 10 seconds as the predetermined time.

  Further, although the case where the accelerator opening degree is applied as an engine load signal for determining the establishment of the release condition for executing the release mode has been described in the ECU 70 of the present embodiment, the present invention is not limited thereto. For example, a torque signal may be applied as the engine load signal, and the satisfaction of the release condition may be determined based on the torque signal.

  Further, in the continuously variable transmission mechanism 2 of the present embodiment, the ECU 70 executes the release mode for releasing the low pressure mode when it is determined that the release condition is satisfied during the execution of the low pressure mode. Although the third hydraulic pressure Pp3 higher than the second hydraulic pressure Pp2 is supplied, it is not limited thereto. For example, when it is determined that the release condition is satisfied during the low pressure mode, the third hydraulic pressure Pp3 higher than the second hydraulic pressure Pp2 may be supplied without executing the release mode.

  Further, in the continuously variable transmission mechanism 2 of the present embodiment, the movable sheave 25 is in direct contact with the fixed side member 36 and positioned in the axial direction when forming the maximum gear ratio. Is not limited. For example, the movable sheave 25 may be positioned in the axial direction indirectly in contact with the fixed side member 36 via a spring member or another buffer member when forming the maximum gear ratio. Alternatively, for example, the primary shaft 22 has a stepped portion or a flange portion between the movable sheave 25 and the fixed side member 36 in the axial direction, and the movable sheave 25 has these stepped portions or flanges when forming the maximum gear ratio. It may be in contact and axially positioned. Furthermore, the primary shaft 22 has a stopper member which is a separate member fixed between the movable sheave 25 and the fixed side member 36 in the axial direction, and the movable sheave 25 abuts against the stopper member when forming the maximum gear ratio. It may be positioned in the axial direction.

  In the continuously variable transmission mechanism 2 according to the present embodiment, the first pulley is the primary pulley 26 and the second pulley is the secondary pulley 31. However, the present invention is not limited to this. For example, the first pulley for setting the transmission gear ratio may be a secondary pulley, and the second pulley for setting a belt clamping pressure may be a primary pulley. In this case, the maximum gear ratio of the continuously variable transmission mechanism is formed when the movable sheave of the secondary pulley is closest to the fixed sheave side and the diameter of the secondary pulley is maximized. The movable sheave of the secondary pulley is axially positioned in direct or indirect contact with the stationary sheave of the secondary pulley when forming the maximum transmission ratio. Alternatively, the movable sheave of the secondary pulley is axially positioned by abutting through a stepped portion or a flange portion formed on the rotation shaft of the secondary pulley at the time of formation of the maximum gear ratio, or a stopper member fixed to the rotation shaft. Ru. Even in such a continuously variable transmission mechanism, when forming the maximum gear ratio, the low pressure mode in which the secondary pulley pressure is set to a second oil pressure lower than the first oil pressure for forming the maximum gear ratio when traveling is set. The belt slippage at the start can be prevented by supplying the third hydraulic pressure Pp3 higher than the second hydraulic pressure Pp2 in the release mode.

  The present embodiment at least includes the following configuration. The vehicle drive system (1) of the present embodiment includes a first pulley (26) having a first fixed sheave (23) and a first movable sheave (25), and a second fixed sheave (29). And a second pulley (31) having a second movable sheave (30), a belt wound around the first pulley (26) and the second pulley (31), and a first pulley pressure Is supplied to the first hydraulic fluid chamber (41) for pressing the first movable sheave (25) to set the gear ratio, and the second pulley pressure is supplied to the second hydraulic fluid chamber (41). And a second hydraulic oil chamber (46) for setting the belt clamping pressure by pressing and controlling the movable sheave (30), and the first movable sheave (25) being engaged in the rotational direction and sliding in the axial direction The rotation shaft (22) which is movably supported, and the axial direction with respect to the rotation shaft (22) A pressure receiving member (36) fixed with the first movable sheave (25) and forming the first hydraulic oil chamber (41), the first movable sheave (25) being fixed A stepless speed change mechanism (2) in which movement in a direction away from the first fixed sheave (23) in the axial direction is restricted at the time of formation of a maximum gear ratio, and pressure regulation of the first pulley pressure The transmission control of the continuously variable transmission mechanism (2) is performed by transmitting a control signal to the pressure regulation unit (83) and the pressure regulation unit (83), and the gear ratio of the continuously variable transmission mechanism (2) is maximized. When the rotation of the second pulley (31) is stopped with the gear ratio set, the second hydraulic pressure (Pp1) lower than the first hydraulic pressure (Pp1) for forming the maximum gear ratio during traveling Possible to execute low pressure mode to supply hydraulic pressure (Pp2) to the first hydraulic oil chamber (41) A control unit (70), the control unit (70) being configured to transmit a torque equal to or greater than a predetermined torque from the drive source (8) to the first pulley (26) during the low pressure mode; If it is determined that the release condition is satisfied and it is determined that the release condition is satisfied, the third hydraulic pressure (Pp3) higher than the second hydraulic pressure (Pp2) is supplied to the first hydraulic oil chamber (41) Do.

  According to this configuration, the control unit (70) is a release condition that includes transmission of torque of a predetermined torque or more from the drive source (8) to the first pulley (26) during execution of the low pressure mode at the time of stopping. Is determined, and it is determined whether or not a stall state has occurred. When the control unit (70) determines that the release condition is satisfied, the control unit (70) supplies the third hydraulic pressure (Pp3) higher than the second hydraulic pressure (Pp2) to the first hydraulic oil chamber (41). . As a result, the third hydraulic pressure (Pp3) higher than the second hydraulic pressure (Pp2) can be supplied before the continuously variable transmission mechanism (2) in the low pressure mode generates an upshift. Even when the first pulley pressure that forms the maximum gear ratio is in a low pressure mode in which the first pulley pressure is set to a lower pressure than during travel, the belt slippage at the start can be prevented.

  Further, in the vehicle drive device (1) of the present embodiment, the third hydraulic pressure (Pp3) is smaller than the first hydraulic pressure (Pp1). According to this configuration, by suppressing the increase in the first pulley pressure, it is possible to maintain good fuel consumption while preventing belt slippage at the time of start.

  Further, in the vehicle drive device (1) of the present embodiment, the third hydraulic pressure (Pp3) is equal to the first hydraulic pressure (Pp1). According to this configuration, it is possible to reliably prevent belt slippage at the time of start, and when the brake is turned off to start, it is possible to travel by supplying the same first pulley pressure as in normal travel. .

  Further, in the vehicle drive device (1) of the present embodiment, the control unit (70) intermittently detects the engine load signal equal to or more than the first threshold during execution of the low pressure mode and detects a predetermined number of times. Alternatively, when the engine load signal equal to or higher than the second threshold is continuously detected for a predetermined time, it is determined that the release condition is satisfied. According to this configuration, torque is transmitted from the drive source (8) to the first pulley (26) in any case, but the continuously variable transmission mechanism (2) in the low pressure mode is upshifted. Since the third hydraulic pressure (Pp3) can be supplied before occurrence of the belt slippage at the start can be prevented.

  In the vehicle drive device (1) of the present embodiment, when the third hydraulic pressure (Pp3) is zero at the accelerator opening, and when the rotation of the second pulley (31) is stopped. It is a hydraulic pressure supplied prior to the execution of the low pressure mode. Here, when the accelerator opening is increased from zero while maintaining the rotation stop of the second pulley (31) during the low pressure mode, the first pulley pressure is the base pressure according to the accelerator opening. Ascending from the second hydraulic pressure (Pp2), which is a temporary increase when the accelerator opening exceeds zero, and returning the accelerator opening to zero, the first pulley pressure is the base pressure Return to a certain second hydraulic pressure (Pp2). Therefore, according to this configuration, when it is determined that the release condition is satisfied, the base pressure supplied at the time when the accelerator opening is zero is the third hydraulic pressure (Pp3) higher than the second hydraulic pressure (Pp2). When it is determined that the release condition is satisfied, the accelerator opening degree is increased from zero and the first pulley pressure is increased, and then the first pulley pressure is the second hydraulic pressure if the accelerator opening degree is returned to zero. It is possible to return to the third hydraulic pressure (Pp3) higher than Pp2).

  Further, in the vehicle drive device (1) of the present embodiment, the control unit (70) determines that the release condition is satisfied, and determines that the second pulley (31) is rotating. In this case, the first hydraulic pressure (Pp1) is supplied to the first hydraulic oil chamber (41). According to this configuration, when it is determined that the release condition is satisfied, when the brake is turned off and the vehicle is started, it is possible to travel by supplying the first pulley pressure as in the normal travel.

  In the vehicle drive device (1) of the present embodiment, the first pulley (26) is a primary pulley (26) to which rotation from the drive source (8) can be transmitted. The pulley (31) is a secondary pulley (31) capable of transmitting the rotation to the wheel. Here, in the power transmission path, the primary pulley (26) on the drive source (8) side is more likely to receive torque of a predetermined torque or more from the drive source (8) than the secondary pulley (31) on the wheel side, and belt slippage occurs. It's easy to do. For this reason, according to this configuration, it is possible to prevent belt slippage in the primary pulley (26) which is more likely to cause belt slippage than the secondary pulley (31), so that belt slippage of the continuously variable transmission mechanism (2) can be more effectively achieved. It can be suppressed.

  Further, in the vehicle drive device (1) according to the present embodiment, the wheel side pulley (31) in the power transmission path of the first pulley (26) and the second pulley (31) is the wheel The rotation of the wheel-side pulley (31) can be stopped by means of a braking device that can stop the rotation of the wheel. According to this configuration, the rotation of the pulley (31) on the wheel side can be stopped by a brake device such as a foot brake or a hand brake.

  Further, the vehicle drive device (1) of the present embodiment includes a fluid transmission (6) interposed between the drive source (8) and the continuously variable transmission mechanism (2). According to this configuration, when the rotation of the continuously variable transmission mechanism (2) is stopped by the brake device, the drive source (8) can be driven.

  In the vehicle drive device (1) of the present embodiment, the control unit (70) releases the low voltage mode when it is determined that the release condition is satisfied during the low voltage mode. A release mode is executed, and in the release mode, the third hydraulic pressure (Pp3) higher than the second hydraulic pressure (Pp2) is supplied to the first hydraulic fluid chamber (41). According to this configuration, the control unit (70) can supply the third hydraulic pressure (Pp3) to the first hydraulic oil chamber (41) by executing the release mode.

1 Automatic transmission (drive for vehicle)
2 Continuously variable transmission mechanism 6 Torque converter (fluid transmission)
8 Internal combustion engine (drive source)
22 Primary axis (rotational axis)
23 Fixed sieve (first fixed sieve)
25 movable sheave (first movable sheave)
26 Primary pulley (first pulley)
29 Fixed sieve (second fixed sieve)
30 Movable sheave (2nd movable sheave)
31 Secondary pulley (second pulley)
32 belt 36 fixed side member (pressure receiving member)
41 Primary-side hydraulic oil chamber (first hydraulic oil chamber)
46 Secondary side hydraulic oil chamber (second hydraulic oil chamber)
70 Electronic control unit (ECU) (control unit)
83 Shift control unit (pressure regulator)
Pp1 First hydraulic pressure Pp2 Second hydraulic pressure Pp3 Third hydraulic pressure

Claims (10)

A first pulley having a first stationary sheave and a first movable sheave, a second pulley having a second stationary sheave and a second movable sheave, the first pulley and the second pulley A belt to be wound, a first hydraulic pressure chamber for pressing and controlling the first movable sheave by supplying a first pulley pressure, and a second pulley pressure are supplied. A second hydraulic oil chamber for pressing and controlling the second movable sheave to set the belt clamping pressure, and the first movable sheave being engaged in the rotational direction and axially slidable And a pressure receiving member fixed in the axial direction with respect to the rotating shaft and forming the first hydraulic fluid chamber between the rotating shaft and the first movable sheave; The first moving sheave with respect to the first fixed sheave at the time of formation of the maximum gear ratio A continuously variable transmission mechanism moving in the direction is restricted away in the axial direction,
A pressure control unit that adjusts the first pulley pressure;
While transmitting control of the continuously variable transmission mechanism by transmitting a control signal to the pressure regulating unit, the rotation of the second pulley is stopped in a state where the speed ratio of the continuously variable transmission mechanism is set to the maximum speed ratio. A control unit capable of executing a low pressure mode for supplying a second hydraulic pressure lower than a first hydraulic pressure for forming the maximum gear ratio to the first hydraulic oil chamber when traveling; Equipped
The control unit determines a release condition including transmission of a torque equal to or greater than a predetermined torque from the drive source to the first pulley during execution of the low pressure mode, and determines that the release condition is satisfied. The vehicle drive device for supplying a third hydraulic pressure higher than the second hydraulic pressure to the first hydraulic oil chamber.   The vehicle drive device according to claim 1, wherein the third hydraulic pressure is smaller than the first hydraulic pressure.   The vehicle drive system according to claim 1, wherein the third hydraulic pressure is equal to the first hydraulic pressure.   The control unit intermittently detects an engine load signal equal to or more than a first threshold while detecting the engine load signal equal to or more than a second threshold continuously during execution of the low pressure mode. The vehicle drive device according to any one of claims 1 to 3, wherein it is determined that the release condition is satisfied in the case where it is determined.   The third hydraulic pressure according to any one of claims 1 to 4, wherein the third hydraulic pressure is hydraulic pressure which is supplied before the execution of the low pressure mode when the accelerator opening is zero and when the rotation of the second pulley is stopped. The vehicle drive device according to any one of the preceding claims.   When the control unit determines that the release condition is satisfied and determines that the second pulley is rotating, the first hydraulic pressure is supplied to the first hydraulic oil chamber. The vehicle drive device according to any one of to 5. The first pulley is a primary pulley capable of transmitting rotation from the drive source,
The vehicle drive device according to any one of claims 1 to 6, wherein the second pulley is a secondary pulley capable of transmitting rotation to a wheel.   The pulley on the wheel side in the power transmission path of the first pulley and the second pulley is drivably connected to the wheel, and the rotation of the pulley on the wheel side can be stopped by the brake device capable of stopping the rotation of the wheel The vehicle drive device according to any one of claims 1 to 7, which can be stopped.   The vehicle drive device according to any one of claims 1 to 8, further comprising a fluid transmission device interposed between the drive source and the continuously variable transmission mechanism. When the control unit determines that the release condition is satisfied during execution of the low pressure mode, the control unit executes a release mode for releasing the low pressure mode, and the release mode is higher than the second hydraulic pressure in the release mode. The vehicle drive device according to any one of claims 1 to 9, wherein a third hydraulic pressure is supplied to the first hydraulic fluid chamber.

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