JP5045426B2 - Continuously variable transmission for vehicle - Google Patents

Description

  The present invention relates to an improvement in a continuously variable transmission for a vehicle incorporating a toroidal type continuously variable transmission that is used as an automatic transmission for a vehicle (automobile). Specifically, for example, an appropriate driving force (creep force) corresponding to a road surface condition (for example, a road surface inclination state or a step state) can be output from the output shaft without using a tilt sensor or the like. The structure is realized.

  The use of a toroidal-type continuously variable transmission as an automobile transmission is described in, for example, Patent Documents 1 and 2, and is partially implemented and well known. In addition, a continuously variable transmission that combines a toroidal continuously variable transmission and a planetary gear type transmission in order to increase the fluctuation range of the gear ratio has also been widely used, for example, as described in Patent Documents 3 to 5. Are known. FIGS. 5 and 6 include an operation mode described in Patent Documents 4 and 5 in which a so-called geared neutral state can be realized in which the output shaft 9 can be stopped while the input shaft 3 is rotated in one direction. A continuously variable transmission is shown. FIG. 5 shows a block diagram of the continuously variable transmission, and FIG. 6 shows a hydraulic circuit for controlling the continuously variable transmission.

  The output of the engine 1 is input to the input shaft 3 via the damper 2. The power transmitted to the input shaft 3 is transmitted directly or via a toroidal type continuously variable transmission 4 to a planetary gear type transmission 5 which is a gear type differential unit. The differential components of the constituent members of the planetary gear type transmission 5 are taken out to the output shaft 9 via the clutch device 6, that is, the low speed and high speed clutches 7 and 8 shown in FIG. The toroidal continuously variable transmission 4 includes input and output disks 10 and 11, a plurality of power rollers 12, a plurality of trunnions (not shown), each of which is a support member, and an actuator 13. (FIG. 6), a pressing device 14, and a transmission ratio control unit 15. Of these, the input-side and output-side disks 10 and 11 are arranged concentrically and relatively freely rotatable.

  Each of the power rollers 12 is sandwiched between the inner surfaces of the input and output disks 10 and 11 facing each other, and the power roller 12 is driven between the input and output disks 10 and 11. (Torque) is transmitted. Each trunnion supports each power roller 12 rotatably. The actuator 13 is of a hydraulic type, and the trunnions supporting the power rollers 12 are displaced in the axial directions of the pivots provided at both ends so that the input side disk 10 and the output side The gear ratio with the disk 11 is changed. The pressing device 14 is of a hydraulic type and presses the input side disk 10 and the output side disk 11 in a direction approaching each other. The gear ratio control unit 15 controls the displacement direction and the displacement amount of the actuator 13 so that the gear ratio between the input side disk 10 and the output side disk 11 becomes a desired value.

  In the case of the illustrated example, the transmission ratio control unit 15 includes a controller 16, a stepping motor 17 that is switched based on a control signal from the controller 16, a line pressure control electromagnetic on-off valve 18, and an electromagnetic valve. 19, a shift electromagnetic valve 20, and a control valve device 21 whose operation state can be switched by these members 17 to 20. The control valve device 21 includes a gear ratio control valve 22, a correction cylinder 23, correction control valves 24a and 24b, and high-speed clutch and low-speed clutch switching valves 25 and 26 (FIG. 6). It is a thing. Of these, the gear ratio control valve 22 controls the supply and discharge of hydraulic pressure to the actuator 13. The correction cylinder 23 is configured to correct the transmission ratio of the toroidal continuously variable transmission 4 in accordance with the torque (passing torque) passing through the toroidal continuously variable transmission 4. Is to adjust the switching state. The correction control valves 24 a and 24 b control the supply and discharge of pressure oil to and from the correction cylinder 23 and are switched according to switching of the electromagnetic valve 19. Further, the switching valves 25 and 26 for the high speed clutch and the low speed clutch switch the introduction state of the pressure oil to the low speed and high speed clutches 7 and 8, respectively.

  Moreover, the pressure oil discharged from the oil pump 27 (27a, 27b in FIG. 6) driven by the power extracted from the damper 2 portion is sent to the control valve device 21 and the pressing device 14. That is, the pressure oil sucked from the oil reservoir 28 (FIG. 6) and discharged by the oil pumps 27a and 27b is adjusted to a predetermined pressure by the pressing force adjusting valve 29 and the low pressure side adjusting valve 30 (FIG. 6). Of these, the pressing force adjusting valve 29 includes a hydraulic pressure corresponding to a hydraulic pressure difference (differential pressure) existing between a pair of hydraulic chambers 31 a and 31 b provided with a piston 38 sandwiched between the actuator 13, and the aforementioned The valve opening pressure is adjusted based on the introduction of hydraulic pressure based on the opening / closing of the line pressure control electromagnetic switching valve 18 controlled by a command from the controller 16. Then, based on such adjustment of the valve opening pressure, the pressing force generated by the pressing device 14 is regulated to an optimum value according to the operating condition.

  In addition, the pressure oil adjusted by the pressure adjusting valve 29 in this way is sent to the actuator 13 through the speed ratio control valve 22, the manual hydraulic pressure switching valve 32, the pressure reducing valve 33, the high speed clutch, The low speed clutch 7 or the high speed clutch 8 is fed into the hydraulic chamber through the low speed clutch switching valves 25 and 26. The low speed clutch 7 out of the low speed and high speed clutches 7 and 8 is connected when realizing a low speed mode in which the speed reduction ratio is increased {including the gear ratio infinite (including the geared neutral state = GN state)}. At the same time, the connection is broken when the high speed mode for reducing the reduction ratio is realized. In contrast, the high speed clutch 8 is disconnected when realizing the low speed mode and is connected when realizing the high speed mode. The supply / discharge state of the pressure oil to the low speed and high speed clutches 7 and 8 is switched according to the switching of the shift solenoid valve 20.

  FIG. 7 shows an example of the relationship between the speed ratio (speed increase ratio) of the toroidal-type continuously variable transmission 4 and the speed ratio (speed increase ratio) of the continuously variable transmission as a whole. For example, in the low speed mode in which the low speed clutch 7 is connected and the high speed clutch 8 is disconnected, the transmission ratio of the toroidal continuously variable transmission 4 can be realized in the GN state as indicated by the solid line α. As the speed is decelerated from the value (GN value), the speed ratio of the continuously variable transmission as a whole is increased from the stopped state (speed ratio 0 state) to the forward direction (+: forward rotation direction). Similarly, as the speed increases from the GN value, the speed is also increased in the backward direction (-: reverse direction) from the stopped state. On the other hand, in the high speed mode in which the high speed clutch 8 is connected and the low speed clutch 7 is disconnected, as indicated by the solid line β, the speed ratio of the toroidal continuously variable transmission 4 is increased. The speed ratio of the continuously variable transmission as a whole can be increased (in the forward direction).

  In general, “speed ratio” is a reduction ratio, “speed ratio” is an increase ratio, and the reciprocal of “speed ratio” is “speed ratio” (“speed ratio” = 1 / “ Gear ratio "). However, in the present specification and claims, the term “speed ratio” is used for the ratio between the input side and the output side for the toroidal type continuously variable transmission, and the input side for the entire continuously variable transmission is The term “speed ratio” is used for the ratio to the output side. The reason for this is to make it easy to clarify whether it is the ratio of the toroidal type continuously variable transmission or the ratio of the continuously variable transmission as a whole. Therefore, in the present specification and claims, the “speed ratio” does not necessarily correspond to the reduction ratio, and the “speed ratio” does not necessarily correspond to the speed increase ratio.

  In a vehicle incorporating a continuously variable transmission as described above, based on the vehicle's current driving condition (driving condition) obtained from the accelerator pedal operation (accelerator opening) and the vehicle's driving speed (vehicle speed). The controller 16 obtains the optimum speed ratio (target speed ratio) of the continuously variable transmission. In order to achieve this target speed ratio, the stepping motor 17 is driven based on the control signal of the controller 16 and the speed ratio control valve 22 is switched, so that the speed ratio of the toroidal continuously variable transmission 4 is The target speed ratio corresponding to the target speed ratio is adjusted. At the same time, the connecting / disconnecting states of the low speed and high speed clutches 7 and 8 are switched by switching the shift solenoid valve 20 as necessary (in accordance with the target speed ratio of the continuously variable transmission). Then, the necessary travel mode (low speed mode or high speed mode) is selected. Thus, the speed ratio of the continuously variable transmission is adjusted to an optimum value (target speed ratio) according to the running state of the vehicle at that time.

  In the case of the continuously variable transmission configured as described above, in the low speed mode, the output shaft 9 is stopped while the input shaft 3 is rotated (a geared neutral state is realized), or an extreme It is necessary to properly regulate the torque (passing torque) that passes through the toroidal type continuously variable transmission 4 while rotating at low speed. For this reason, in the case of the structure described in Patent Document 4 described above, the toroidal continuously variable transmission is adjusted in accordance with the rotational speed while roughly controlling the rotational speed of the engine 1 that drives the input shaft 3. By adjusting the gear ratio of 4, the torque passing through the toroidal continuously variable transmission 4 is regulated to a target value. In Patent Document 4, the output shaft 9 is stopped while the input shaft 3 is rotated (in a state where the transmission gear ratio is infinite). A technique for adjusting (correcting) the gear ratio of the toroidal-type continuously variable transmission 4 is also described so that torque (driving force, creep force) to the extent that the vehicle can be driven by the vehicle can be transmitted.

  Specifically, for example, when the vehicle is stopped, the shift lever (control lever) is moved from a non-traveling state such as a P range (parking position) or an N range (neutral position) to a D range (normally forward position), an L range ( When operated in a driving state such as a high driving force advance position) or an R range (reverse position), the creeping force (driving force) corresponding to the operation position (D, L, R range) is continuously variable. The transmission gear ratio of the toroidal type continuously variable transmission 4 is adjusted so that the output shaft 9 can output. Note that the creep force that is output when the shift lever is operated in this way is almost the same as the creep force (drive force) that is output by a widely used automatic transmission (with a torque converter). It is set to become. The reason for this is to make it possible to obtain the same starting performance as that of such a widespread automatic transmission with such a continuously variable transmission. However, if the creep force output from the continuously variable transmission is set according to (same as) a widely used automatic transmission, such a widely used automatic transmission. In the same way, the following inconvenience may occur. Furthermore, in the case of a continuously variable transmission that does not have a torque converter, the engine may stop when the vehicle is stopped on a steep uphill or when traveling at a low speed.

  In other words, in the case of the automatic transmissions that are widely used as described above and continuously variable transmissions that set a creep force in accordance with the automatic transmissions, the vehicle stops on a flat road or a gentle uphill with respect to the traveling direction, for example. If it is in a state, the shift lever is operated from the P range to the D range, and the operation of braking devices such as the foot brake and the parking brake is released (the brake pedal is released or the parking lever is returned to the original position). In this case, it is considered that the vehicle can start and run at a low speed (even if the accelerator pedal is not depressed). Furthermore, it is considered that the vehicle can be accelerated in the forward direction by depressing the accelerator pedal from this state. In such a case, there is no particular inconvenience. On the other hand, when the vehicle is stopped on a steep uphill in the traveling direction, for example, depending on the magnitude of the creep force, the accelerator pedal may be released after releasing the brake device (some degree). Until the vehicle is stepped on, the vehicle may not be started (the vehicle may remain stopped), or the vehicle may start to move in a direction opposite to the driver's intended starting direction.

  That is, in the case of the automatic transmissions that are widely used as described above (and continuously variable transmissions in which the creep force is set according to this), the magnitude of the creep force that is output from the output shaft at the start is set in advance. It depends on the engine torque and the rotational speed (and the gear ratio of the toroidal continuously variable transmission at the time of starting) in the idling state (the state where the accelerator pedal is not depressed). In other words, the creep force is determined according to the preset torque and rotational speed (and gear ratio), and the magnitude does not change unless the accelerator pedal is depressed. Therefore, when the magnitude of the creep force determined in this way is the same or smaller than the force (running resistance) determined according to the road slope (gradient) and the vehicle weight applied to the output shaft via the wheels In addition, the vehicle may remain stopped as described above, or may start moving in the opposite direction. In particular, when the vehicle starts to move in the opposite direction, for example, as with the reverse phenomenon that occurs when a vehicle incorporating a manual transmission is advanced on a slope, there is a possibility that the passenger including the driver may feel uncomfortable. In addition, when the vehicle is traveling at a low speed based only on the creep force with the accelerator pedal and the brake pedal depressed (released), for example, when the vehicle approaches an uphill, the inclination angle of the uphill ( Depending on the gradient, the vehicle may stop or start moving in the opposite direction, as in the case described above. Furthermore, in the case of a continuously variable transmission that does not have a torque converter, which is a kind of fluid coupling, there is a possibility that the engine load becomes excessive for an idling state and the engine is stopped (engine stalled).

  In order to prevent such inconvenience, an inclination sensor for detecting the inclination of the road surface is provided, and an engine (in an idling state) is selected according to the magnitude (gradient) of the inclination detected by the inclination sensor. It is possible to adjust the output of the engine (aside from the driver's accelerator operation). However, in this case, it is necessary to newly provide a tilt sensor, which is not preferable because the cost increases. It is also conceivable to provide a rotation sensor to detect that the vehicle starts to move in an unintended direction and adjust the output of the engine, for example, according to the detection result. However, in this case, it is necessary to accurately detect rotation at an extremely low speed. For example, when an inexpensive electromagnetic pickup type is used as the rotation sensor, there is a possibility that sufficient accuracy cannot be ensured. On the other hand, if a rotation sensor that can detect rotation detection at an extremely low speed with sufficient accuracy is used, the cost of the rotation sensor increases, and there is a possibility that the same inconvenience as in the case of using the tilt sensor described above may occur.

Japanese Patent No. 2734583 JP-A-5-39850 JP-A-10-103461 JP 2004-225888 A JP 2004-211836 A

  In view of the circumstances as described above, the present invention provides an appropriate driving force (creep force) according to the road surface condition (for example, road surface inclination state, step state, etc.) where the vehicle is located, without using, for example, an inclination sensor. Is invented to realize a continuously variable transmission for a vehicle that can be output from an output shaft.

The continuously variable transmission for a vehicle according to the present invention includes, for example, a toroidal continuously variable transmission, a gear-type differential unit, and the like in the conventional continuously variable transmission shown in FIGS. It consists of a combination.
Among these, the toroidal continuously variable transmission includes at least a pair of disks, a plurality of power rollers, and a plurality of support members. Each of these disks is supported concentrically so as to be freely rotatable relative to each other. The power rollers are sandwiched between the disks. The support members rotatably support the power rollers. Then, the gear ratio between the two disks is changed by displacing the support members by a hydraulic actuator .
The differential unit is a combination of a plurality of gears.
Then, by adjusting the gear ratio of the toroidal continuously variable transmission and changing the relative displacement speeds of the plurality of gears constituting the differential unit, the input shaft is driven by a drive source (for example, a traveling engine). The rotation state of the output shaft can be converted into forward rotation and reverse rotation with the stop state sandwiched in a state where it is rotated in one direction.
In particular, in the continuously variable transmission for a vehicle according to the present invention, the selected position of the shift lever (operation lever, select lever) is in the traveling state (for example, D, L, R range), and the vehicle is not stopped. When the vehicle is traveling at a speed lower than a predetermined speed (for example, 3 km / h) and the braking device and the accelerator device are deactivated (for example, the parking brake is released and the brake pedal and the accelerator pedal are released). The toroidal type is based on a difference in hydraulic pressure (differential pressure) between a pair of hydraulic chambers constituting the actuator, which changes according to a torque (passing torque) passing through the toroidal type continuously variable transmission. The speed ratio of the continuously variable transmission is adjusted to adjust the speed ratio of the entire continuously variable transmission incorporating this toroidal continuously variable transmission (for example, the speed of the entire continuously variable transmission). Decrease the speed ratio or increase the speed ratio or keep the value at that time). In this way, by adjusting the speed ratio of the continuously variable transmission as a whole, a desired (appropriate) response according to the road surface condition where the vehicle is located {for example, the road surface slope state (gradient), step state, etc.} A driving force (creep force) is output from the output shaft.

In the case of the continuously variable transmission according to the present invention, the differential pressure and the torque (passing torque) are not associated with each other, and the transmission ratio of the toroidal continuously variable transmission is set according to only the differential pressure. The speed ratio of the entire continuously variable transmission incorporating this toroidal type continuously variable transmission is adjusted. That is, since the torque (passing torque) and the differential pressure have a correlation with each other (corresponding to each other), the gear ratio of the toroidal continuously variable transmission is adjusted directly from the differential pressure , and the toroidal The speed ratio of the continuously variable transmission incorporating the step transmission is adjusted. In such a case, since only the differential pressure is used, that is, the operation for obtaining the torque (passing torque) from the differential pressure is not required (the operation for associating the differential pressure with the torque is not required). Accordingly, a controller that performs arithmetic processing for outputting a desired (appropriate) driving force (creep force) from the output shaft can be simply configured.

Further, in the case of the present invention, using the differential pressure corresponding to the passing torque, when the passing torque (differential pressure) is equal to or less than the first threshold, the speed ratio of the continuously variable transmission as a whole is The speed increases toward a predetermined value (until the first predetermined value) at a predetermined change speed (shift speed).
For example, when the vehicle weight is about 2 t (2000 kg) and the adjustment is performed based on the differential pressure, the first threshold value related to the differential pressure is set to, for example, about 200 [kPa] in absolute value. The reason why the threshold value related to the differential pressure is an absolute value is that the differential pressure is positive or negative depending on whether the selected position of the shift lever is the forward position (D, R range) or the reverse state (R range). is there. That is, the positive / negative of the differential pressure is determined by whether the force (hydraulic pressure) applied in either direction is a positive value or a negative value with respect to the axial direction of the piston constituting the actuator. The positive / negative of the differential pressure corresponds to the direction of torque (passing torque) passing through the toroidal type continuously variable transmission, and further to the direction of driving force (creep force) output from the output shaft. For example, in the embodiment described later, the differential pressure generated when the driving force (passing torque) in the direction of moving the vehicle forward is applied {when the shift lever is operated to the forward position (D, L range)} is negative. (Minus), and the differential pressure generated when the driving force (passing torque) in the direction of reversing the vehicle is applied {when the shift lever is operated to the reverse position (R range)} is positive (plus).

  However, in any case (regardless of whether the differential pressure corresponding to which traveling direction is positive or negative), the absolute value of the differential pressure (passing torque) decreases in the traveling direction. This means that the driving force (passing torque) in the corresponding direction becomes small (means that the resistance to the traveling direction becomes small). Then, if an appropriate first threshold value is set (defined) from the relationship between the road surface on which the vehicle is located and the differential pressure (passing torque) corresponding to the road surface, that is, the first threshold value is, for example, a flat road. If the boundary value between the vehicle and the uphill is set (defined), it is possible to determine that the road surface condition where the vehicle is located is a flat road or a downhill with respect to the traveling direction when the value is equal to or less than the first threshold. In such a case, if the speed ratio of the continuously variable transmission as a whole is increased, the speed of the vehicle can be increased smoothly, and the driving intended by the driver can be performed.

  When the speed ratio of the continuously variable transmission as a whole is increased in this way, the first predetermined value that is the upper limit value of the speed ratio, that is, the value of the passing torque (differential pressure) is the first value. A value for stopping the speed increasing operation of the speed ratio of the continuously variable transmission is set (defined) in advance even if it remains below one threshold. The reason is that if the speed increase is excessive, the speed of the vehicle becomes too high, and for example, the driver may be forced to operate a braking device (for example, a foot brake). The first predetermined value (value for stopping the speed increase) can be set (defined) as a value of the speed ratio of the continuously variable transmission as a whole, and the speed ratio of the toroidal continuously variable transmission can be changed. The number of steps of the stepping motor (driving device), the value of the gear ratio of the toroidal type continuously variable transmission, and the speed (vehicle speed) of the vehicle can be set (specified).

  For example, when setting (defining) corresponding to the number of steps of the stepping motor, the selection position of the shift lever, for example, is based on the number of steps that can realize the geared neutral state (GN state) as a reference (0 [step]). It can be set (specified) to −60 [step] for the forward position (D, L range), and +40 [step] for the reverse position (R range). When the passing torque (differential pressure) is equal to or less than a first threshold value (absolute value is 200 [kPa]), the stepping motor has a step number of −60 [step] or +40. Drive toward [step] to increase the speed ratio of the continuously variable transmission as a whole. Further, for example, when setting (specifying) corresponding to the gear ratio of the toroidal continuously variable transmission, for example, the speed increasing ratio can be set to 1.5 (for example, when the shift lever is in the forward position). . When the passing torque (differential pressure) is equal to or less than a first threshold value (absolute value is 200 [kPa]), the transmission ratio of the toroidal continuously variable transmission is 1.5 ( (Speed increase ratio) to increase the speed ratio of the continuously variable transmission as a whole. Further, for example, when it is defined in correspondence with the vehicle speed, it can be set to 10 km / h, for example. When the passing torque (differential pressure) is equal to or less than a first threshold value (200 kPa absolute value if differential pressure), the continuously variable transmission until the vehicle speed reaches 10 km / h. Increase the overall speed ratio.

Further, as in the invention described in claim 2, when the passing torque (differential pressure) exceeds the first threshold and is less than the second threshold, the continuously variable transmission as a whole The speed ratio is maintained as it is at that time (the speed ratio is kept constant, for example, a stepping motor for shifting is not driven). Also in this case, for example, when the weight of the vehicle is about 2 t (2000 kg) and the adjustment is performed based on the differential pressure, the second threshold value is set to, for example, about 400 [kPa] in absolute value. Similarly to the case of the first threshold value, the second threshold value is set to an appropriate value from the relationship between the road surface on which the vehicle is located and the differential pressure (passing torque) corresponding to the road surface. In other words, an increase in the absolute value of the differential pressure (passing torque) means that the driving force (passing torque) in the direction corresponding to the traveling direction increases (the resistance to the traveling direction increases). ). Then, from the relationship between the road surface on which the vehicle is located and the differential pressure (passing torque) corresponding to the road surface, for example, the second threshold value is set between a gentle uphill slope and a steep uphill slope. If the boundary value is set, it can be determined that the road surface condition where the vehicle is located is a gentle uphill in the traveling direction when the first threshold value is exceeded and less than the second threshold value. In such a case, if the speed ratio of the continuously variable transmission is maintained as it is, the speed of the vehicle can be increased constantly or gradually, and the vehicle can smoothly (slowly) travel on this gentle uphill {driver Can run as intended}.

Further, as in the invention described in claim 3, when the passing torque (differential pressure) is equal to or greater than the second threshold value, the speed ratio of the continuously variable transmission as a whole is set to a second predetermined value. Toward the vehicle (until the second predetermined value is reached) at a predetermined change speed (shift speed). That is, when the second threshold is set as described above, and the passing torque (differential pressure) is equal to or higher than the second threshold, the road surface where the vehicle is located has a steep uphill in the traveling direction. (Or there is a step). In such a case, if the speed ratio of the continuously variable transmission as a whole is kept at the value at that time, excessive torque is applied to the drive source (engine), and this drive source is stopped (engine stop). )there's a possibility that. Therefore, when the passing torque (differential pressure) is not less than the second threshold as described above, the speed ratio of the continuously variable transmission as a whole is reduced. As described above, when the speed ratio of the continuously variable transmission as a whole is decelerated, the second predetermined value that is the lower limit value of the speed ratio, that is, the value of the passing torque (differential pressure) is the second value. A value for stopping the deceleration operation of the speed ratio of the continuously variable transmission is set (defined) in advance even if the value remains above the threshold value.

  Such a second predetermined value is the speed ratio of the continuously variable transmission as a whole, for example, “speed ratio 0”, that is, the output shaft can be stopped while the input shaft is rotated in one direction. Set (specify) the neutral state (GN state). For example, in the case of setting (specifying) corresponding to the number of steps of the stepping motor (driving device), the number of steps that can realize the GN state is set. Further, when setting (specifying) the value corresponding to the speed ratio value of the toroidal type continuously variable transmission, the value is set to a value (GN point) that can realize the GN state. In any case, as the speed ratio of the continuously variable transmission as a whole is reduced, a larger driving force (creep) can be output in the traveling direction. Even in the state where the second predetermined value which is the lower limit value is reached, the speed ratio of the continuously variable transmission as a whole becomes 0, that is, the GN state, so that the drive source is stopped (engine stop). ) Can be reliably prevented from traveling in the opposite direction to the traveling direction.

  When the second predetermined value is set (defined) to a value that deviates from the “speed ratio 0 (GN state)”, depending on the value (speed ratio, speed ratio, number of steps), the driving source There is a possibility that the vehicle stops or the vehicle starts moving in the direction opposite to the traveling direction intended by the driver (the direction corresponding to the selected position of the shift lever). That is, when the second predetermined value is set to a value that is greatly deviated from the “speed ratio 0 (GN state)”, the drive source may stop. In addition, if the sign (traveling direction) is set to a value that reverses across the “speed ratio 0 (GN state)”, the vehicle may start moving in the reverse direction. Therefore, the second predetermined value is set (defined) in a range in which the drive source does not stop (for example, a range in which the GN state can be realized based on torque shift) and in a range in which the traveling direction does not reverse (preferably, Set to “speed ratio 0”).

Further, when the present invention as described above is implemented, it is more preferable that the processes according to the inventions as described in claims 1 to 3 are related to each other as in the inventions described in claims 4 to 6. The speed ratio of the entire step transmission is adjusted more finely. Specifically, as in the invention described in claim 4, the passing torque (differential pressure) is increased in a state where the speed ratio of the entire continuously variable transmission is increased toward the first predetermined value. When the first threshold value is exceeded, the speed ratio is held at the value at that time. Further, as in the invention described in claim 5, in the state where the speed ratio of the entire continuously variable transmission is decelerated toward the second predetermined value, the passing torque (differential pressure) is When it becomes less than the threshold value, the speed ratio is maintained as the value at that time. Further, as in the invention described in claim 6, the passing torque (differential pressure) is not less than the second threshold value in a state where the speed ratio of the continuously variable transmission as a whole is maintained at a constant value. The speed ratio is decelerated at a predetermined change speed toward the second predetermined value, and when the speed ratio is also equal to or lower than the first threshold, the speed ratio is changed to the first predetermined value. The speed is increased at a predetermined change rate toward.

  The speed ratio change speed (speed change speed) when changing the speed ratio of the continuously variable transmission according to the passing torque (differential pressure) is, for example, a step speed of a stepping motor (drive device) 5 [ step / sec]. Such a change speed can be made different, for example, when the speed ratio is decelerated and when the speed ratio is increased. It is also possible to change the speed of change according to the magnitude of the difference between the measured value (actual value) of the passing torque (differential pressure) and the first and second threshold values.

According to the continuously variable transmission of the present invention as described above, for example, without using an inclination sensor or the like, it is possible to select an appropriate vehicle according to the road surface condition (for example, the road surface inclination state (gradient), step state, etc.). Driving force (creep force) can be output from the output shaft.
That is, a force (torque) according to the road surface condition and the total vehicle weight is applied to the output shaft of the continuously variable transmission through the wheels. Then, the torque (passing torque) that passes through the toroidal-type continuously variable transmission, and consequently the hydraulic pressure difference (differential pressure) between the pair of hydraulic chambers that constitute the actuator, which changes according to the passing torque. Changes based on the force applied to the output shaft via the wheels (they have a correlation with each other). In this case, the total vehicle weight differs depending on, for example, the type (vehicle type) of the vehicle, but an optimal value can be set for each vehicle type in advance, and at that time by a weight sensor, a load sensor, or the like. The total vehicle weight can be obtained (the total vehicle weight can be obtained anyway). Further, the output torque of the drive source (engine) can be obtained in advance in correspondence with the operation state of the accelerator device, for example. Therefore, the selected position of the shift lever is the running state (D, L, R range) (the clutch device is connected), and the vehicle is not stopped and travels below a predetermined speed (eg, less than 3 km / h). When the braking device and the accelerator device are deactivated (for example, the parking brake is released and the brake pedal and the accelerator pedal are released), the force applied to the output shaft, i.e., this The road surface condition (gradient, step, etc.) can be determined based on the value of the passing torque (and thus the differential pressure) corresponding to the force.

Therefore, in the case of the present invention, the value of the passing torque (differential pressure) and the road surface condition {tilt (gradient), step, etc.} are associated in advance (a threshold value corresponding to the road surface condition is set in advance). ), Adjusting the gear ratio of the toroidal continuously variable transmission according to the value of the passing torque (differential pressure), and adjusting the speed ratio of the continuously variable transmission incorporating the toroidal continuously variable transmission. By doing so, a desired (appropriate) driving force (creep force) according to the road surface condition where the vehicle is located can be output from the output shaft. That is, when the passing torque (differential pressure) is a value corresponding to a downhill, the speed ratio of the toroidal continuously variable transmission is adjusted within a range where the speed of the vehicle does not become excessively high. The speed ratio of the continuously variable transmission incorporating the continuously variable transmission is increased, and the driving force (creep force) is adjusted to an appropriate value (the driving force is reduced). When the passing torque (differential pressure) is a value corresponding to an uphill, the gear ratio of the toroidal continuously variable transmission is adjusted within a range in which the drive source (engine) does not stop (engine stop) , The speed ratio of the entire continuously variable transmission incorporating this toroidal continuously variable transmission is reduced, and the driving force (creep force) is adjusted to an appropriate value (the driving force is increased). Therefore, when the vehicle starts or when traveling at a very low speed, the vehicle can travel according to the driver's intention, for example, ensuring a stable start feeling and reducing the driver's fatigue. .

FIG. 1 shows an example of an embodiment of the present invention. The feature of this example is that between a pair of hydraulic chambers 31a and 31b (see FIG. 6) constituting the actuator 13 that changes according to the torque passing through the toroidal type continuously variable transmission 4 (see FIG. 5). Based on the hydraulic pressure difference (differential pressure), a desired driving force (creep force) corresponding to the road surface condition (tilt state, step state, etc.) where the vehicle incorporating the continuously variable transmission is located is output shaft 9 (see FIG. (See 5). Since the structure and operation of other parts are the same as those of the conventional structure shown in FIGS. 5 to 6 described above, overlapping illustrations and explanations are omitted or simplified, and the following description will focus on the characteristic parts of this example. In the case of this example, the relationship between the speed ratio (speed increase ratio) of the continuously variable transmission as a whole and the speed ratio (speed increase ratio) of the toroidal-type continuously variable transmission 4 is shown, for example, in FIG. It is set like this. Such a setting can be performed, for example, by restricting the reduction ratio of the planetary gear type transmission 5 (see FIG. 5) and the gear ratio of the transmission gear.

Further, the speed of the continuously variable transmission in the low speed mode, that is, the mode in which the geared neutral state (GN state) in which the output shaft 9 is stopped while the input shaft 3 (see FIG. 5) is rotated in one direction can be realized. The relationship between the ratio, the transmission ratio of the toroidal-type continuously variable transmission 4, and the number of steps of the stepping motor 17 (see FIGS. 5 and 6) for changing the transmission ratio corresponds as shown in Table 1 below. is doing.

In the case of this example, as in the conventional structure shown in FIGS. 5 and 6, the trunnions (support members) that support the power rollers 12 are respectively attached to both ends by the hydraulic actuators 13. The gear ratio between the input side disk 10 and the output side disk 11 (see FIG. 5) can be changed by being displaced in the axial direction of the provided pivot. Further, a difference in hydraulic pressure (differential pressure) existing between a pair of hydraulic chambers 31a and 31b provided with the piston 38 sandwiched between such an actuator 13 is determined by, for example, a pair of hydraulic sensors 39a and 39b (FIG. 6). Reference is made possible by 39) in FIG. Then, a differential pressure between the hydraulic chambers 31a and 31b is obtained from the hydraulic pressure of the hydraulic chambers 31a and 31b detected by the hydraulic sensors 39a and 39b, and the toroidal type is calculated based on the differential pressure. By adjusting the speed ratio of the continuously variable transmission 4 and adjusting the speed ratio of the entire continuously variable transmission incorporating this toroidal continuously variable transmission , a desired (in accordance with the road surface condition where the vehicle is located ( An appropriate driving force (creep force) is output from the output shaft 9.

In order to output such a desired (appropriate) driving force (creep force), refer to the flowchart of FIG. 1 for the function (differential pressure sensitive shift control) provided in the controller 16 (see FIG. 5). I will explain. The work shown in this flowchart is repeatedly (automatically) performed from when the ignition switch is turned on until it is turned off.
First, in step 1, the controller 16 determines whether or not the driver is operating the shift lever to the running state (D, L, R range). This determination is made by detecting whether the shift lever is in the forward position (D, L range) or the reverse position (R range) with the position switch 34 (see FIG. 5). If it is determined in step 1 that the shift lever is not operated in the traveling state, that is, it is operated in the non-traveling state (N, P range), the process is terminated without performing the subsequent processing (end). To return to step 1). This is because when the shift lever is in the non-running state (N, P range), it is not necessary to perform the gear ratio control (differential pressure sensitive shift control) of this example.

  On the other hand, if it is determined that the shift lever is operated in the traveling state (D, L, R range), in the next step 2, whether or not the vehicle is traveling, in other words, the vehicle speed is 0 km / h. It is determined whether or not. This determination is made based on, for example, a signal from the output shaft rotation sensor 35 (see FIG. 5) for detecting the rotation speed of the output shaft 9 or a vehicle speed sensor provided separately. If it is determined in step 2 that the vehicle is not traveling, that is, the vehicle is stopped, the following process is not performed and the process ends (returns to step 1 via the end). This is because it is not necessary to perform the speed ratio control (differential pressure sensitive speed change control) of this example when the vehicle is stopped. On the other hand, if it is determined that the vehicle is traveling, that is, the vehicle speed is not 0 km / h, whether or not the vehicle is traveling below a predetermined speed, for example, less than 3 km / h, in the next step 3. Determine whether. If it is determined in step 3 that the vehicle is traveling at a predetermined speed or higher, for example, 3 km / h or higher, the process is terminated without performing the subsequent process (returns to step 1 via the end). This is because when the vehicle is traveling at 3 km / h or more, the shift control (differential pressure sensitive shift control) of this example is not performed, and normal shift control is performed.

  On the other hand, if it is determined that the vehicle is traveling at a speed less than a predetermined speed, for example, less than 3 km / h, whether or not the braking device is operated in the next step 4, that is, the brake pedal is depressed. Is released (released) or not (the parking brake is also released as necessary). This determination is made based on, for example, an ON / OFF signal of the brake switch 36 (see FIG. 5). If it is determined in step 4 that the depression of the brake pedal is not released, that is, the brake pedal is depressed (or the parking brake is activated), the subsequent processing is performed. The process ends (returns to step 1 via the end). When the brake pedal is depressed (or the parking brake is activated) in this way, the brake pedal is depressed without performing the shift control (differential pressure sensitive shift control) of this example. This is because the shift control required in the state (or the state where the parking brake is operating) is performed.

  On the other hand, if it is determined that the brake pedal is not depressed {the brake pedal is released (released)} (and that the parking brake is also released), In step 5, it is determined whether or not the accelerator device is operated, that is, whether or not the depression of the accelerator pedal is released (released). This determination is performed based on a signal from the accelerator sensor 37 (see FIG. 5). If it is determined in step 5 that the accelerator pedal is depressed, the process is terminated without performing the subsequent process (returns to step 1 via the end). When the accelerator pedal is depressed in this way, the shift control (differential pressure sensitive shift control) of this example is not performed, and the normal shift control according to the depression amount (accelerator opening) of this accelerator pedal is performed. Because of that.

  On the other hand, if it is determined that the accelerator pedal is not depressed {the accelerator pedal is depressed (released)}, the next step 6 is to provide the actuator 13 with the piston 38 interposed therebetween. It is determined whether or not the difference in hydraulic pressure (differential pressure) existing between the pair of hydraulic chambers 31a and 31b is equal to or less than the first threshold A (current differential pressure dP ≦ A). This determination is made based on the measured values of the hydraulic sensors 39a and 39b. When measuring the differential pressure, whether the differential pressure is positive or negative is a negative value in which direction the force (hydraulic pressure) applied to the axial direction of the piston 38 constituting the actuator 13 is set to a positive value. It depends on what you want to do. The positive / negative of the differential pressure corresponds to the direction of torque (passing torque) passing through the toroidal-type continuously variable transmission 4, and further to the direction of creep force (driving force) output from the output shaft 9. In this example, the differential pressure generated when creep force (passing torque) in the direction of moving the vehicle forward is applied {when the shift lever is operated to the forward position (D, L range)} is negative (minus). The differential pressure generated when a creep force (passing torque) in the direction of moving the vehicle backward is applied {when the shift lever is operated to the reverse position (R range)} is positive (plus).

  However, in any case (regardless of whether the differential pressure corresponding to which traveling direction is positive or negative), the absolute value of the differential pressure is reduced in the direction corresponding to the traveling direction. This means that the driving force (passing torque) becomes small (means that the resistance to the traveling direction becomes small). Then, by setting (specifying) an appropriate first threshold value A from the relationship between the road surface on which the vehicle is located and the differential pressure corresponding to the road surface, that is, the first threshold value A is flat, for example. By setting (defining) the boundary value between the road and the uphill, when the current differential pressure is not more than the first threshold A, the road surface condition where the vehicle is located is a flat road or a downhill with respect to the traveling direction. It can be determined that there is. In such a case, if the speed ratio of the continuously variable transmission as a whole is increased, the speed of the vehicle can be increased smoothly, and the driving intended by the driver can be performed. In this example, the weight of the vehicle is about 2 t (2000 kg), and the first threshold value A is 200 [kPa] in absolute value.

  If it is determined in step 6 that the absolute value of the current differential pressure is equal to or less than the first threshold value A (current differential pressure ≦ 200 [kPa]), the process proceeds to steps 7 and 8 and steplessly. The speed ratio of the transmission as a whole is increased (shift-up shifting is performed). However, when the speed ratio of the continuously variable transmission as a whole is increased in this way, the first predetermined value that is the upper limit value of the speed ratio, that is, the value of the differential pressure is not more than the first threshold A. Even with (current differential pressure ≦ 200 [kPa]), it is necessary to set (specify) a value for stopping the speed increasing operation of the speed ratio of the continuously variable transmission in advance. The reason is that if the speed increase is excessive, the speed of the vehicle becomes too high, for example, and the driver may be forced to operate the braking device. Therefore, in this example, in step 7, it is determined whether or not the number of steps [step] of the stepping motor 17 has reached the number of steps corresponding to the upper limit value. Specifically, in step 7, the current step number of the stepping motor 17 is equal to or greater than the step number C corresponding to the first predetermined value (current step number [step] ≧ C [step]). It is determined whether or not.

  The number of steps C [step] corresponding to the first predetermined value is, for example, the selected position of the shift lever is the forward position (D) with reference to the number of steps that can realize the geared neutral state (GN state) (0 [step]). , L range), -60 [step], and if it is in the reverse position (R range), +40 [step]. When it is determined in step 7 that the current step number (absolute value) is not equal to or greater than C [step] (absolute value), that is, it is still less than C [step] (absolute value). Proceeds to step 8 and adjusts the gear ratio of the toroidal continuously variable transmission 4 to increase the speed ratio of the continuously variable transmission. For example, if the selected position of the shift lever is the forward position (D, L range), it is driven in the negative (minus) direction by 1 [step], and the gear ratio of the toroidal continuously variable transmission 4 is reduced. Then, the speed ratio of the continuously variable transmission as a whole is increased in the forward direction (see Table 1 above). On the other hand, if the selection position of the shift lever is the reverse position (R range), the shift lever is driven in the positive (plus) direction by 1 [step] to increase the speed ratio of the toroidal continuously variable transmission 4. The speed ratio of the continuously variable transmission as a whole is increased in the reverse direction (see Table 1 above). When the speed ratio of the entire continuously variable transmission is increased by 1 [step] of the stepping motor 17 in step 8 as described above, the process returns to step 1 through completion.

  On the other hand, if it is determined in step 7 that the current number of steps (absolute value) is equal to or greater than the C [step] (absolute value), the process proceeds to step 9 where the speed ratio of the continuously variable transmission is determined. The current value is maintained (the driving of the stepping motor 17 is stopped). Even if the differential pressure is equal to or less than the first threshold A (current differential pressure ≦ 200 [kPa]), the speed of the vehicle is excessively increased by stopping the speed ratio increase of the continuously variable transmission. Therefore, it is possible to prevent the driver from operating the braking device (for example, foot brake). The first predetermined value for stopping the speed ratio increase of such a continuously variable transmission is defined according to the number of steps of the stepping motor 17 as described above, and the toroidal continuously variable transmission. It can also be set (specified) in correspondence with the value of the gear ratio of 4 and the vehicle speed (vehicle speed). In this case, when using the gear ratio of the toroidal type continuously variable transmission 4, for example, when the C corresponding to the first predetermined value is set to 1.5 as the speed increasing ratio, or when the vehicle speed is used, Similarly, it can be 10km / h. When this vehicle speed is used, an appropriate value is set together with the vehicle speed in step 3 (for example, the vehicle speed in step 3 is also set to a threshold of 10 km / h). In any case, if the speed ratio of the continuously variable transmission as a whole is maintained as it is without driving the stepping motor 17 in step 9 as described above, the process returns to step 1 via the end. .

  On the other hand, if it is determined in step 6 that the absolute value of the current differential pressure exceeds the first threshold value A (current differential pressure> 200 [kPa]), the process proceeds to step 10 where this difference is determined. It is determined whether or not the pressure is greater than or equal to a second threshold value B (current differential pressure dP ≧ B). Similarly to the case of the first threshold value A, the second threshold value B is set to an appropriate value from the relationship between the road surface on which the vehicle is located and the differential pressure corresponding to the road surface. That is, an increase in the absolute value of the differential pressure means that the driving force (passing torque) in the direction corresponding to the traveling direction increases (means that the resistance in the traveling direction increases). Then, from the relationship between the road surface on which the vehicle is located and the differential pressure corresponding to the road surface, for example, the second threshold B is set to a boundary value between a gentle uphill and a steep uphill of the uphill. If set, when the differential pressure exceeds the first threshold A and is less than the second threshold B, the road surface condition where the vehicle is located is a gentle uphill in the traveling direction. Can be judged. In such a case, if the speed ratio of the continuously variable transmission is maintained as it is, the speed of the vehicle can be increased constantly or gradually, and the gentle uphill can be smoothly (slowly) And) (can drive as intended by the driver). In the case of this example, the weight of the vehicle is about 2 t (2000 kg), and the second threshold value B is 400 [kPa] in absolute value.

  If it is determined in step 10 that the absolute value of the current differential pressure is not greater than or equal to the second threshold value B (current differential pressure dP <400 [kPa]), the process proceeds to step 9 to The speed ratio of the step transmission is maintained at the current value (the driving of the stepping motor 17 is stopped). By stopping the speed ratio of the continuously variable transmission, the vehicle speed is increased to a constant value or gradually, and the vehicle travels smoothly (slowly) on a gentle uphill (the vehicle travels as intended by the driver). ) Because. If the speed ratio of the continuously variable transmission as a whole is maintained as it is without driving the stepping motor 17 in step 9 as described above, the process returns to step 1 via the end. On the other hand, if it is determined in step 10 that the absolute value of the current differential pressure is greater than or equal to the second threshold value B (current differential pressure dP ≧ 400 [kPa]), steps 11 and 12 are performed. Then, the speed ratio of the continuously variable transmission as a whole is decelerated (shift down shifting is performed). That is, when the second threshold value B is set as described above, when the differential pressure becomes equal to or higher than the second threshold value B, the road surface condition where the vehicle is located is a steep uphill ( Or there is a step). In such a case, if the speed ratio of the continuously variable transmission as a whole is kept at the value at that time, an excessive torque is applied to the engine 1 (see FIG. 5) as a drive source, and the engine 1 is stopped. There is a possibility of engine stop. For this reason, the speed ratio of the continuously variable transmission as a whole is reduced as described above.

  In the case of this example, even when the speed ratio of the continuously variable transmission as a whole is reduced, the second predetermined value that is the lower limit value of the speed ratio, that is, the value of the differential pressure is The value for stopping the speed ratio reduction operation of the continuously variable transmission is set (specified) in advance even when the value is equal to or higher than the second threshold (current differential pressure dP ≧ 400 [kPa]). In this example, such a second predetermined value is set so that the speed ratio of the continuously variable transmission as a whole is 0 (speed ratio 0), that is, the output shaft 9 is rotated while the input shaft 3 is rotated in one direction. The so-called geared neutral state (GN state) is stopped. Therefore, in step 11, it is determined whether or not the number of steps of the stepping motor 17 has reached the number of steps that can realize the GN state. Specifically, in step 11, whether or not the current step number of the stepping motor 17 is 0 [step] (current step number = 0 [step]) corresponding to the second predetermined value. Determine.

  If it is determined in step 11 that the current number of steps is not 0 [step], the process proceeds to step 12 where a toroidal-type continuously variable transmission is performed to reduce the speed ratio of the continuously variable transmission. The gear ratio of the machine 4 is adjusted. For example, if the selected position of the shift lever is the forward position (D, L range), the stepping motor 17 is driven in the positive direction by 1 [step], and the toroidal continuously variable transmission 4 is driven. And the speed ratio of the continuously variable transmission as a whole is decelerated in the forward direction (see Table 1 above). On the other hand, if the selected position of the shift lever is the reverse position (R range), the stepping motor 17 is driven in the negative (minus) direction by 1 [step] to change the speed of the toroidal continuously variable transmission 4. The ratio is decelerated, and the speed ratio of the continuously variable transmission as a whole is decelerated in the reverse direction (see Table 1 above). As the speed ratio of the continuously variable transmission as a whole is reduced in this way, a greater driving force (creep) in the traveling direction can be output. If the speed ratio of the entire continuously variable transmission is reduced by 1 [step] of the stepping motor 17 in step 12, the process returns to step 1 after completion.

  On the other hand, if it is determined in step 11 that the current number of steps is 0 [step], the process proceeds to step 9 where the speed ratio of the continuously variable transmission as a whole remains at the current value. Maintain (stop driving of stepping motor 17). In such a state, since the output shaft 9 can be stopped while the input shaft 3 is rotated in one direction as described above, the engine 1 does not stop (engine stop), and the vehicle Can be reliably prevented from moving in the opposite direction. The second predetermined value for stopping the deceleration of the speed ratio of the continuously variable transmission can be set (defined) in correspondence with the value of the transmission ratio of the toroidal continuously variable transmission 4. . In this case, the transmission ratio is set to a value (GN point) that can realize the GN state. In any case, if the step ratio motor 17 is not driven and the speed ratio of the continuously variable transmission as a whole is maintained as it is (currently in the GN state) in step 9, as described above, Return to step 1.

In the case of this example as described above, an appropriate driving force (creep) according to the road surface condition (for example, the road surface inclination state (gradient), step state, etc.) without using the inclination sensor or the like, for example. Force) is output from the output shaft 9.
That is, a force (torque) according to the road surface condition and the total vehicle weight is applied to the output shaft 9 of the continuously variable transmission through the wheels. The torque passing through the toroidal-type continuously variable transmission 4 (passing torque) and, in turn, the hydraulic pressure between the pair of hydraulic chambers 31a and 31b constituting the actuator 13, which changes according to the passing torque. The difference (differential pressure) changes based on the force applied to the output shaft 9 via the wheels (they have a correlation with each other). In this case, the total vehicle weight differs depending on, for example, the type (vehicle type) of the vehicle, but an optimal value can be set for each vehicle type in advance, and at that time by a weight sensor, a load sensor, or the like. The total vehicle weight can be obtained (the total vehicle weight can be obtained anyway). Also, the output torque of the engine 1 can be obtained in advance in correspondence with the operating state of the accelerator device, for example. Therefore, the selected position of the shift lever is the running state (D, L, R range) {the low speed clutch 7 (see FIG. 5) is connected}, the vehicle is not stopped and less than the predetermined speed (3 km when the brake device and the accelerator device are released (for example, the parking brake is released and the brake pedal and the accelerator pedal are released), the output shaft 9 The road surface condition (gradient, step, etc.) can be determined based on the force applied to the vehicle, that is, the value of the differential pressure corresponding to this force.

In the case of this example, the value of the differential pressure is associated with the road surface condition {tilt (gradient), step, etc.} in advance (a threshold value corresponding to the road surface condition is set in advance) By adjusting the speed ratio of the toroidal type continuously variable transmission 4 according to the value of the differential pressure and adjusting the speed ratio of the entire continuously variable transmission incorporating this toroidal type continuously variable transmission , A desired (appropriate) driving force (creep force) corresponding to the road surface condition is positioned so as to be output from the output shaft 9. That is, when the differential pressure is a value corresponding to a downhill, the speed ratio of the toroidal continuously variable transmission 4 is adjusted within a range where the speed of the vehicle does not become excessively high, and the toroidal continuously variable. The speed ratio of the entire continuously variable transmission incorporating the transmission is increased, and the driving force (creep force) is adjusted to an appropriate value (the driving force is reduced). When the differential pressure is a value corresponding to an uphill, the transmission ratio of the toroidal continuously variable transmission 4 is adjusted so that the engine 1 does not stop (engine stop). The speed ratio of the entire continuously variable transmission incorporating the transmission is reduced, and the driving force (creep force) is adjusted to an appropriate value (the driving force is increased). Therefore, when the vehicle starts or when traveling at a very low speed, the vehicle can travel according to the driver's intention, for example, ensuring a stable start feeling and reducing the driver's fatigue. .

  FIG. 2 shows a change in the state quantity of the vehicle when the shift control of this example is performed on a vehicle (automobile) having a weight of 2 t (2000 kg). FIG. 2 shows an example of a change when the shift lever is operated to the D range (forward position) on a flat road (when the vehicle is moved forward). In FIG. 2, when the depression of the brake pedal is released from the state where the accelerator pedal is not depressed (see a in FIG. 2) and the brake pedal is depressed (see b in FIG. 2) ( The vehicle starts to move based on the idling rotation of the engine (see FIG. 2d). At this time, since the absolute value of the differential pressure of the actuator is 200 [kPa] or less (see e in FIG. 2), the stepping motor is driven toward −60 [step] (see f in FIG. 2), and the stepless motor The speed ratio of the transmission as a whole is increased in the forward direction (the speed ratio of the toroidal type continuously variable transmission is decelerated from 1.7 as the GN point; see g in FIG. 2). Then, the speed of the vehicle gradually increases (see h in FIG. 2), and the vehicle speed becomes 3 [Km / h] or more (see i in FIG. 2).

In the above description, the gear ratio of the toroidal continuously variable transmission 4 is adjusted, and the speed ratio of the entire continuously variable transmission incorporating this toroidal continuously variable transmission is adjusted. The description has been given of the case where the operation is performed based on the differential pressure generated between the hydraulic chambers 31a and 31b. However, this differential pressure changes according to the torque (passing torque) passing through the toroidal type continuously variable transmission 4 (having a correlation). However, although it is out of the technical scope of the present invention, the inclination state of the road surface is determined based on this passing torque (for example, by directly detecting the passing torque with a torque sensor or the like) instead of the differential pressure ( And adjusting the speed ratio of the toroidal continuously variable transmission 4 and adjusting the speed ratio of the entire continuously variable transmission incorporating the toroidal continuously variable transmission. it can.

Japanese Patent Application No. 2006-26573 discloses a technique for determining an inclination state of a road surface on which a vehicle is located based on a differential pressure (passing torque). Even when such a technique is employed, the same shift control as that in the above-described example can be performed. That is, with this technique, for example, when the road slope is determined to be “flat road”, the speed ratio of the continuously variable transmission is increased until the vehicle speed reaches the optimum creep vehicle speed (for example, 10 km / h). (Corresponding to the processing of steps 7 and 8 in this example). Also, for example, when the road slope is determined to be “downhill”, the speed ratio of the continuously variable transmission is increased until a predetermined vehicle speed (for example, 30 km / h) higher than the optimum creep vehicle speed is exceeded. (Corresponding to steps 7 and 8 in this example). For example, when it is determined that the slope state of the road surface is “gradual uphill”, the current gear ratio is maintained (corresponding to step 9 in this example). Further, for example, when it is determined that the road slope is “steep uphill”, the gear ratio of the continuously variable transmission is reduced (corresponding to steps 11 and 12 in this example).
In the case of increasing the speed ratio of the continuously variable transmission including the case of the present invention, the limit value of the acceleration is set within a range in which engine knock due to excessive acceleration does not occur (for example, “ (In the case of “flat road” or “gentle downhill”) and within a range in which the necessary engine braking force is not lost (for example, in the case of “steep downhill”).

  Further, in the case of the technique disclosed in the above-mentioned Japanese Patent Application No. 2006-26573, the road surface condition where the vehicle is located is an uphill in the traveling direction by determining whether the pressure difference is positive or negative along with the change in the pressure difference value. It is determined whether there is a downhill. On the other hand, in the example of the above-described embodiment, the positive / negative determination of the differential pressure is not performed (without going through the step of determining whether it is uphill or downhill), and based on the absolute value of the differential pressure. Shift control is performed. However, even if the shift control based on the absolute value of the differential pressure is performed in this way (even if the shift control is the same between the uphill and the downhill), the shift control according to the road surface condition where the vehicle is located can be performed. The reason for this is as follows. That is, in one example of the above-described embodiment, for example, when the differential pressure is 200 [kPa] or less in absolute value, it is determined that the road surface state is flat or downhill, and the speed of the continuously variable transmission is determined. Increase the ratio. Here, the “downhill” in this case is a gentle downhill where the differential pressure does not exceed 200 [kPa] in absolute value. Therefore, regardless of whether the differential pressure value is positive or negative (whether it is a flat road or a gentle downhill), the speed ratio of the continuously variable transmission can be increased so that the speed of the vehicle is smooth. Raised.

  If the differential pressure exceeds 200 [kPa] in absolute value and less than 400 [kPa], the speed ratio of the continuously variable transmission is maintained at the value at that time. Here, the absolute value of the differential pressure is “200 <| differential pressure | <400 [kPa]”, “+200 <differential pressure <+400 [kPa]”, and “−200> differential”. Pressure> −400 [kPa] ”differs depending on whether the road surface state where the vehicle is located is an uphill or a downhill. In the example of the embodiment described above, it is assumed that the road surface condition is a gentle uphill, and the speed ratio of the continuously variable transmission is maintained at the value at that time. Even if the actual road surface condition is downhill, no problem occurs. In other words, the “downhill” in this case is a moderate downhill whose absolute value of the differential pressure exceeds 200 [kPa] and less than 400 [kPa]. And even if it is such a moderate descent, since the speed ratio of the continuously variable transmission is maintained at the value at that time as described above, the braking force based on the engine brake can be obtained, and the driver It is possible to prevent forced operation of the braking device. In short, when the differential pressure exceeds 200 [kPa] in absolute value and less than 400 [kPa], the speed ratio of the continuously variable transmission is maintained at the value at that time. Regardless of whether it is uphill or downhill, a gentle uphill can run smoothly on this gentle uphill, and a moderate downhill requires the required engine braking force (braking force). Can be obtained.

  When the differential pressure exceeds 400 [kPa] in absolute value, the speed ratio of the continuously variable transmission is reduced. Also in this case, the road surface state where the vehicle is located is an uphill when the differential pressure is “differential pressure> +400 [kPa]” and “differential pressure <−400 [kPa]”. Or downhill. In the example of the above-described embodiment, the road surface condition is assumed to be a steep uphill, and the speed ratio of the continuously variable transmission is decelerated. For example, the differential pressure is reversed, and the actual road surface condition is Even if it is downhill, no problem arises. That is, the “downhill” in this case is a steep downhill where the absolute value of the differential pressure exceeds 400 [kPa]. And even if it is such a steep downhill, since the speed ratio of the continuously variable transmission is reduced as described above, a large braking force based on the engine brake can be obtained. It is possible to prevent excessive acceleration of the vehicle. In short, when the differential pressure exceeds 400 [kPa] in absolute value, the speed ratio of the continuously variable transmission is decelerated, so whether the differential pressure is positive or negative (whether uphill or downhill). ), A large driving force (creep force) can be obtained on a steep uphill, and a large engine braking force (braking force) can be obtained on a steep downhill.

  As described above, in the case of the example of the above-described embodiment, even if the absolute value of the differential pressure is used (without determining whether the differential pressure is positive or negative), an appropriate value according to the road surface state where the vehicle is located is used. Driving force (creep force) can be output. In other words, an appropriate driving force (creep force) corresponding to each of the uphill and the downhill can be output even if the shift control of the uphill and the downhill is the same (shared). For this reason, the number of steps processed by the controller 16 can be reduced by not requiring a step for determining whether the differential pressure is positive or negative, the burden of the arithmetic processing of the controller 16 can be reduced, and Increase speed. If necessary, a step for determining whether the differential pressure is positive or negative can be provided, and the speed ratio of the continuously variable transmission can be adjusted through this step. In such a case, finer speed change control can be performed, such as adjustment of different speed ratios between the uphill and the downhill.

  In the example of the embodiment described above, it is determined in step 2 (see FIG. 1) whether or not the vehicle is running. It is also possible to omit (the step 2 is skipped). That is, even when the vehicle is stopped, the operation (except for step 2) shown in the flowchart of FIG. 1 described above can be repeated (automatically). The change in the state quantity of the vehicle when configured in this manner is shown in FIGS. 3 to 4, similarly to FIG. 2 described above, the weight of the vehicle (automobile) is about 2 t (2000 kg). 3 shows an example of the change when the shift lever is operated to the D range (forward position) on the uphill in the traveling direction (when the vehicle is advanced), and FIG. 4 similarly shows the shift lever in the D range. Examples of changes when the vehicle is moved to the (advance position) and over the road step are shown.

  First, in FIG. 3, which shows a change on an uphill, this brake is applied from a state where the accelerator pedal is not depressed (see a in FIG. 3) and the brake pedal is depressed (see b in FIG. 3). Even if the depression of the pedal is released (see c in FIG. 3), the vehicle does not move (see d in FIG. 3). At this time, since the absolute value of the differential pressure of the actuator is 200 [kPa] or less (see e in FIG. 3), the stepping motor is driven toward −60 [step] (see f in FIG. 3), and the stepless motor The speed ratio of the transmission as a whole is increased in the forward direction (the speed ratio of the toroidal continuously variable transmission is decelerated from 1.7, which is the GN point, see g in FIG. 3). In this way, while the stepping motor is driven toward -60 [step], the differential pressure exceeds 200 [kPa] (see h in FIG. 3), so the speed ratio at that time is maintained. Therefore, the driving of the stepping motor is stopped (see i in FIG. 3). After that, since the differential pressure is over 200 [kPa] and less than 400 [kPa], the stepping motor is kept stopped, but the accelerator pedal is depressed ( (See i in FIG. 3), and shifts to normal shift control.

  Also, in FIG. 4, which shows a change when climbing over a step, the state where the accelerator pedal is not depressed (see a in FIG. 4) and the brake pedal is depressed (see b in FIG. 4) When the depression of the brake pedal is released (see c in FIG. 4), the vehicle starts to move based on the idling rotation of the engine (see d in FIG. 4). At this time, since the absolute value of the differential pressure of the actuator is 200 [kPa] or less (see e in FIG. 4), the stepping motor is driven toward −60 [step] (see f in FIG. 4), so that it is continuously variable. The speed ratio of the transmission as a whole is increased in the forward direction (the speed ratio of the toroidal-type continuously variable transmission is decelerated from 1.7 as the GN point, see g in FIG. 4). In this way, when the stepping motor is driven toward -60 [step] and the vehicle reaches a step, the differential pressure increases (see h in FIG. 4). Since this differential pressure exceeds 200 [kPa], the stepping motor is stopped to keep the speed ratio at that time (see i in FIG. 4), but the differential pressure further increases. Since this differential pressure exceeds 400 [kPa] (see j in FIG. 4), the stepping motor is driven toward 0 [step] in order to reduce the speed ratio of the continuously variable transmission as a whole (FIG. 4). 4 see k). Thereafter, the differential pressure decreases, and this differential pressure becomes less than 400 [kPa]. Therefore, the driving of the stepping motor is stopped in order to maintain the speed ratio at that time (see l in FIG. 4). Then, when the accelerator pedal is depressed (see m in FIG. 4), the shift to the normal shift control is performed.

The flowchart which shows the operation | movement used as the characteristic of one example of embodiment of this invention. The diagram which shows the example of the change of each state quantity on a flat road. The diagram which shows the example of the change of each state quantity on an uphill. The diagram which shows the example of the change of each state quantity at the time of getting over a level | step difference. The block diagram of the continuously variable transmission used as the object of this invention. The hydraulic circuit diagram of the hydraulic device incorporated in this continuously variable transmission. The diagram which shows one example of the correlation of the speed ratio as the whole continuously variable transmission, and the gear ratio of a toroidal type continuously variable transmission.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Engine 2 Damper 3 Input shaft 4 Toroidal type continuously variable transmission 5 Planetary gear type transmission 6 Clutch device 7 Low speed clutch 8 High speed clutch 9 Output shaft 10 Input side disk 11 Output side disk 12 Power roller 13 Actuator 14 Press device DESCRIPTION OF SYMBOLS 15 Gear ratio control unit 16 Controller 17 Stepping motor 18 Electromagnetic on-off valve for line pressure control 19 Solenoid valve 20 Shifting solenoid valve 21 Control valve device 22 Gear ratio control valve 23 Correction cylinder 24a, 24b Correction control valve 25 For high speed clutch Switching valve 26 Low-speed clutch switching valve 27, 27a, 27b Oil pump 28 Oil reservoir 29 Push pressure adjusting valve 30 Low pressure side adjusting valve 31a, 31b Hydraulic chamber 32 Manual hydraulic switching valve 33 Pressure reducing valve 34 Position switch 35 Output shaft rotation sensor 36 Brake switch 3 An accelerator sensor 38 piston 39 and 39a, 39 b hydraulic pressure sensor

Claims (6)

At least one pair of disks supported concentrically so that they can rotate relative to each other, a plurality of power rollers sandwiched between these disks, and a plurality of supports that rotatably support each of these power rollers A toroidal continuously variable transmission that changes the gear ratio between the two disks by displacing each of these support members with a hydraulic actuator , and a gear type that is a combination of a plurality of gears. By combining the differential unit and adjusting the gear ratio of the toroidal-type continuously variable transmission among them, the relative displacement speed of the plurality of gears constituting the differential unit is changed, so that the input shaft is driven by the drive source. In a continuously variable transmission for a vehicle that can freely convert a rotation state of an output shaft into a forward rotation and a reverse rotation with a stop state sandwiched in a state rotated in one direction.
When the selected position of the shift lever is in a traveling state, the vehicle is not stopped and traveling at a speed lower than a predetermined speed, and the operation of the braking device and the accelerator device is released,
A pair of hydraulic chambers constituting the actuator that change according to the torque passing through the toroidal continuously variable transmission when the torque passing through the toroidal continuously variable transmission is equal to or less than a first threshold value. based on the hydraulic pressure of the difference between each other, the toroidal-type by adjusting the gear ratio of the continuously variable transmission, the speed ratio as a whole toroidal incorporating CVT CVT first predetermined value A continuously variable transmission for a vehicle, wherein a desired driving force according to a road surface condition where the vehicle is located is output from the output shaft by adjusting in a direction of increasing at a predetermined change rate toward the vehicle . When the torque passing through the toroidal-type continuously variable transmission exceeds the first threshold and is less than the second threshold, the speed ratio of the continuously variable transmission as a whole is calculated as The continuously variable transmission for a vehicle according to claim 1, wherein the continuously variable transmission is held as it is. The torque passing through the toroidal type continuously variable transmission, when it is the second threshold or more, the speed ratio of the whole of the continuously variable transmission device, decelerates at a predetermined change rate toward a second predetermined value, claim The continuously variable transmission for vehicles described in any one of 1-2 . When the speed ratio of the continuously variable transmission as a whole is increased toward the first predetermined value and the torque passing through the toroidal continuously variable transmission exceeds the first threshold, the speed ratio is The continuously variable transmission for a vehicle according to claim 1 , wherein the value at that time is maintained. When the speed ratio of the continuously variable transmission as a whole is decelerating toward the second predetermined value and the torque passing through the toroidal continuously variable transmission becomes less than the second threshold value, the speed ratio is The continuously variable transmission for a vehicle according to claim 3 , wherein the value at that time is held as it is. When the torque passing through the toroidal continuously variable transmission is equal to or higher than the second threshold value while maintaining the speed ratio of the entire continuously variable transmission as a constant value, the speed ratio is decelerated at a predetermined rate of change toward a second predetermined value, when the same falls below a first threshold value, the speed ratio and speed increasing at a predetermined rate of change toward the first predetermined value, claim 2 4. A continuously variable transmission for a vehicle according to any one of 4, 5 and 5 .

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