JP2007205502A - Continuously variable transmission - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain the inclining condition of a road surface in the starting direction of a vehicle having a continuously variable transmission incorporated therein without using an expensive inclination sensor. <P>SOLUTION: The difference in oil pressure (differential pressure) existing between a pair of hydraulic chambers constituting an actuator for changing the gear ratio of a toroidal-type continuously variable transmission changes differently by the inclining condition (gradient) of the road surface after release of stepping-in of a brake pedal. Therefore, such a change in differential pressure is detected by, for example, an oil pressure sensor, and the inclining condition of the road surface is determined according to this differential pressure. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an improvement of a continuously variable transmission incorporating a toroidal type continuously variable transmission that is used as an automatic transmission for a vehicle (automobile). For example, the inclination of a road surface in the vehicle starting direction can be achieved without using an inclination sensor. A structure capable of obtaining the state is realized.

  The use of a toroidal type continuously variable transmission as an automobile transmission is described in many publications such as Patent Documents 1 and 2 and Non-Patent Documents 1 and 2, and has been well-known in some implementations. is there. Also, continuously variable transmissions that combine a toroidal type continuously variable transmission and a planetary gear type transmission that is a differential unit in order to increase the fluctuation range of the gear ratio are described in, for example, Patent Documents 3 to 6 and the like. Therefore, it has been widely known. FIGS. 11 to 12 are steplessly equipped with an operation mode described in Patent Documents 5 to 6 and capable of realizing a so-called geared neutral state in which the output shaft is stopped while the input shaft is rotated in one direction. A transmission is shown. Of these, FIG. 11 shows a block diagram of a continuously variable transmission, and FIG. 12 shows a hydraulic circuit that controls 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 to the planetary gear type transmission 5 which is a differential unit, either directly or via the toroidal continuously variable transmission 4. 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. 12), 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 transmission ratio control valve 22, a differential pressure cylinder 23, correction control valves 24a and 24b, and high-speed clutch and low-speed clutch switching valves 25 and 26 (FIG. 12). It is a combination. Of these, the gear ratio control valve 22 controls the supply and discharge of hydraulic pressure to the actuator 13. Further, the differential pressure cylinder 23 is configured to control the transmission ratio control valve so as to correct the transmission ratio of the toroidal type continuously variable transmission 4 according to the torque (passing torque) passing through the toroidal type continuously variable transmission 4. This is for adjusting the switching state of 22. The correction control valves 24 a and 24 b control the supply and discharge of the pressure oil to and from the differential pressure cylinder 23 and are switched according to the 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.

  Also, the pressure oil discharged from the oil pump 27 (27a, 27b in FIG. 12) 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. 12) 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. 12). Among these, the pressing force adjusting valve 29 exists between a pair of hydraulic chambers 32a and 32b provided with the piston 31 sandwiched between the actuator 13 as described in detail in, for example, Patent Document 7 and the like. The valve opening pressure is adjusted based on the introduction of the hydraulic pressure based on the hydraulic pressure according to the hydraulic pressure difference (differential pressure) and the opening and closing of the line pressure control electromagnetic switching valve 18 controlled by the command from the controller 16. The 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 via the speed ratio control valve 22, as well as the manual hydraulic pressure switching valve 34 and the pressure reducing valve 35, for 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. Further, 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.

  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 a low speed. Therefore, in the case of the structure described in Patent Document 5 described above, the toroidal continuously variable transmission is controlled 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. Further, in Patent Document 5, the output shaft 9 is stopped while the input shaft 3 is rotated (in a state where the transmission 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. It should be noted that the creep force output when the shift lever is operated in this manner is the same as the creep force (driving force) 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 in accordance with (same as) the automatic transmissions that are widely used, the following inconvenience may occur. .

  That is, in the case of the above-described widely used automatic transmission and the continuously variable transmission in which the creep force is set in accordance with this, if the vehicle is stopped on a flat road, for example, the shift lever is When operating from the P range to the D range and releasing brake devices such as foot brakes and parking brakes (release the brake pedal or return the parking lever), the accelerator pedal It is thought that the vehicle can be started and run at low speed (if not). 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 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, in response to this detection. 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 Japanese Patent Laid-Open No. 10-196759 JP-A-10-103461 JP 2004-225888 A JP 2004-211836 A JP 2004-76940 A Motoo Aoyama, "Bessed Best Car Red Badge Series 245 / A book that understands the latest mechanics of cars", Sanyusha Co., Ltd./Kodansha Co., Ltd., December 20, 2001, p. 92-93 Hirohisa Tanaka, “Toroidal CVT”, Corona Inc., July 13, 2000

  In view of the circumstances as described above, the present invention is to realize a continuously variable transmission that can determine the state of inclination of a road surface in the traveling direction of a vehicle when the vehicle starts without using a tilt sensor or the like. Invented.

The continuously variable transmission of the present invention is a combination of a toroidal continuously variable transmission and a gear-type differential unit, for example, like the conventionally known continuously variable transmission shown in FIGS. It consists of
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. The gear ratio between the two disks is changed by displacing the support members.
The differential unit is a combination of a plurality of gears.
Then, the input shaft is rotated in one direction by the drive source (engine) 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. In this state, the rotation state of the output shaft can be freely converted into normal rotation and reverse rotation with the stop state interposed therebetween.
In particular, in the continuously variable transmission according to the present invention, the inclination state of the road surface on which the vehicle incorporating the continuously variable transmission is located is based on the torque (passing torque) passing through the toroidal continuously variable transmission. Road surface inclination state determination means for determining is provided.

In the case of implementing such a continuously variable transmission of the present invention, preferably, each of the support members is displaced by a hydraulic actuator as described in claim 2. The road surface inclination state determining means is based on a difference in hydraulic pressure (differential pressure) between a pair of hydraulic chambers constituting the actuator, which changes according to the torque passing through the toroidal continuously variable transmission. Thus, the slope state of the road surface is determined.
In this case, the road surface inclination state can be determined according to only the differential pressure without associating the differential pressure with the torque (passing torque). That is, since the torque and the differential pressure have a correlation (corresponding to each other), the road surface inclination state with respect to the starting direction of the vehicle in which the continuously variable transmission is incorporated is determined directly from the differential pressure. You can also. In this case, since only the differential pressure is used, that is, the operation for obtaining the torque from the differential pressure is not required (the operation for associating the differential pressure with the torque is not required), the determination operation is accordingly performed. The controller for performing can be configured simply.

Also, in any case (whether torque is used or differential pressure corresponding to this torque is used), as described in claim 3, the road surface inclination state determination means is stopped by the vehicle, Immediately before the operation of the braking device (depressing the brake pedal) is canceled on the condition that the selected position of the shift lever is in the traveling state and the braking device is operating (for example, the brake pedal is depressed). Based on the torque (or differential pressure) and the change in torque (or differential pressure) after the release, the inclination state of the road surface is determined.
In this case, more preferably, the determination of the inclination state of the road surface is based on the accelerator opening (engine output) and the gear ratio of the toroidal continuously variable transmission after the operation of the braking device is released (released). Is performed based on the change in the torque (or differential pressure) until at least one of the values starts to change.

The road surface inclination determining means determines the road surface inclination as follows.
First, as described in claim 4, when the torque (or differential pressure) does not change from a value immediately before the operation of the braking device is released, it is determined that the road surface is uphill in the traveling direction. To do.
The case where the torque (or differential pressure) does not change means that the value of the torque (or differential pressure) is maintained within a predetermined value range, that is, immediately before the operation of the braking device is released. Is maintained within the range of the preset value (± h) from the value of.
For example, consider the case where the determination of the inclination is performed based on the differential pressure. In this case, for example, if the weight of the vehicle is about 2 t (2000 kg), the predetermined value h is, for example, about ± 75 [kpa]. When the braking device is released, when the change in the differential pressure is maintained within a range of ± 75 [kpa] with respect to the value before the release, the road surface is gently inclined. It can be judged as an uphill. Specifically, it can be determined that the slope is an uphill with a slope that can start and run at a low speed with a preset creep force, for example, an uphill with a slope of about 1 to 10%.

Further, as described in claim 5, the sign (sign) of the torque (or differential pressure) is also released after a predetermined time has elapsed (for example, 1 second) after the operation of the braking device is released. If the absolute value of this torque (or differential pressure) is increased from the value immediately before being released when it is not reversed (changes from positive to negative or changes from negative to positive) from the previous value, However, it is determined that the uphill has a larger inclination in the traveling direction than when the torque (or differential pressure) does not change.
For example, when the above-described conditions, that is, when the weight of the vehicle is about 2 t (2000 kg) and the determination of the inclination is made based on the differential pressure, the absolute value of the differential pressure increased by more than 75 [kpa]. In this case, it can be determined that the road surface is a steep uphill than the above-described gentle uphill. Specifically, even if it can start with only a preset creep force, it can only travel at a very low speed, or it can not start but it can not start, but it remains on a slope that is stopped, for example, from 10% Can be determined to be an uphill with a large slope.

Further, as described in claim 6, the positive or negative value of the torque (or differential pressure) is a value immediately before the release after a predetermined time (for example, 1 second) after the operation of the braking device is released. The absolute value of this torque (or differential pressure) increases from the value immediately before being released, and the amount of change in this torque (or differential pressure) (the amount of change per unit time, the change) When the speed exceeds a first predetermined amount of change set in advance, it is determined that the road surface is an uphill with a greater inclination in the traveling direction than when the road surface is equal to or less than the first predetermined amount of change. .
For example, when the above-described conditions, that is, when the weight of the vehicle is about 2 t (2000 kg) and the inclination is determined based on the differential pressure, for example, the first predetermined change amount (change speed) is set to 500 [kpa. / Sec], the slope can be determined as follows. That is, when the absolute value of the differential pressure increases exceeding 75 [kpa] and the change speed of the differential pressure is 500 [kpa / sec] or less, it can be determined that the road surface is a slightly steep uphill. . Specifically, it can be determined that the slope is an uphill with a slope of about 10% to 15%, for example, which can travel only at a very low speed even if the vehicle can start with only a preset creep force. On the other hand, when the absolute value of the differential pressure increases exceeding 75 [kpa] and the change speed of the differential pressure exceeds 500 [kpa / sec], it is determined that the road surface is a steep uphill. it can. Specifically, it can be determined that the slope is an uphill with a slope that is not able to start with only a preset creep force but remains stopped, for example, an uphill with a slope greater than 15%.

Further, as described in claim 7, when the absolute value of the torque (or differential pressure) decreases from a value immediately before the operation of the braking device is released, the road surface becomes flat or descends in the traveling direction. Judged to be a slope.
For example, when the above-described conditions, that is, when the vehicle weight is about 2 t (2000 kg) and the inclination is determined based on the differential pressure, the absolute value of the differential pressure has decreased by more than 75 [kpa]. In this case, it can be determined that the road surface is flat or downhill in the traveling direction. Specifically, it can be determined that the road is an uphill or a downhill with a slope of less than 1%, or a downhill with a slope of 1% or more.

In addition, as described in claim 8, the absolute value of the torque (or differential pressure) decreases from a value immediately before the operation of the braking device is released, and the change of the torque (or differential pressure). When the amount (change speed) is equal to or less than a second predetermined change amount set in advance, it is determined that the road surface is flat, and when the second predetermined change amount is exceeded, the road surface advances. Judged to be downhill in the direction.
For example, when the above-described condition, that is, when the weight of the vehicle is about 2 t (2000 kg) and the inclination is determined based on the differential pressure, the second predetermined change amount (change speed) is set to 100 [ kpa / sec]. In this case, when the absolute value of the differential pressure is reduced by more than 75 [kpa] and the change speed of the differential pressure is 100 [kpa / sec] or less, the road surface is flat. Can be determined as a flat road within an uphill or downhill range with a slope of less than 1%. In addition, when the absolute value of the differential pressure decreases over 75 [kpa] and the rate of change of the differential pressure exceeds 100 [kpa / sec], the road surface is downhill in the traveling direction. Specifically, it can be determined that the slope is downhill with a slope of 1% or more.

Further, as described in claim 9, the absolute value of the torque (or differential pressure) decreases from a value immediately before the operation of the braking device is released, and the torque (or differential pressure) changes. When the amount (change speed) exceeds a preset third predetermined change amount, the road surface is a downhill with a larger inclination in the traveling direction than when the road surface is equal to or less than the third predetermined change amount. Is determined.
For example, when the above-described conditions, that is, when the weight of the vehicle is about 2 t (2000 kg) and the determination of the inclination is performed based on the differential pressure, for example, the third predetermined change amount (change speed) is set to 200 [ kpa / sec]. In this case, when the absolute value of the differential pressure is reduced to exceed 75 [kpa] and the rate of change of the differential pressure is 200 [kpa / sec] or less, for example, about 1 to 5%. It can be determined that the slope is downhill. In addition, when the absolute value of the differential pressure is reduced to exceed 75 [kpa] and the rate of change of the differential pressure exceeds 200 [kpa / sec], for example, a downhill with a gradient greater than 5% is used. Can be determined.

Further, as described in claims 10 and 11, the positive or negative of the torque (or differential pressure) is reversed (from positive to negative) after a predetermined time (for example, one second) after the operation of the braking device is released. Or the change amount (change speed) of the torque (or differential pressure) exceeds a preset fourth predetermined change amount (Claim 10), or When the absolute value of the torque (or differential pressure) exceeds a preset first predetermined value (Claim 11), the road surface is the fourth predetermined change amount or the first predetermined value. It is determined that the slope is a descending slope having a larger slope in the traveling direction than in the following case.
For example, when the above-described condition, that is, when the vehicle weight is about 2 t (2000 kg) and the determination of the inclination is performed based on the differential pressure, for example, the fourth predetermined change amount (change speed) is set to 800 [kpa]. / Sec]. In this case, the positive / negative of the differential pressure is reversed after a lapse of a predetermined time, and when the change speed of the differential pressure is 800 kpa / second or less, it is determined that the slope is, for example, a downhill with a slope of less than 10%. it can. Further, when the pressure difference is reversed after a predetermined time has passed and the rate of change of the pressure difference exceeds 800 [kpa / sec], it can be determined that the pressure is downhill with a slope greater than 10%, for example.
Alternatively, when the above-described conditions, that is, the weight of the vehicle is about 2 t (2000 kg) and the determination of the inclination is made based on the differential pressure, the first predetermined value is set to 200 [kpa], for example. In this case, the positive / negative of the differential pressure is reversed after a lapse of a predetermined time, and when the absolute value of the differential pressure is 200 [kpa] or less, it can be determined that the uphill has a slope of less than 10%, for example. In addition, when the positive / negative of the differential pressure is reversed after a predetermined time has elapsed and the absolute value of the differential pressure exceeds 200 [kpa], it can be determined that the slope is a descending slope having a slope greater than 10%, for example.

According to the continuously variable transmission of the present invention as described above, it is possible to obtain the inclination state of the road surface in the traveling direction of the vehicle when the vehicle starts without using an expensive inclination sensor.
That is, when the operation of the braking device (for example, depression of the brake pedal) is released in a state where the vehicle is stopped, the output shaft of the continuously variable transmission depends on the road surface inclination (gradient) and the vehicle weight. A force (torque) is applied via the wheels. In this case, when the shift lever is operated to a traveling state (for example, D, L, R range) (a predetermined clutch device is connected), when the operation of the braking device is released, the toroidal type Torque passing through the continuously variable transmission (passing torque) changes based on the force applied to the output shaft via the wheels. More specifically, when the operation of the braking device is released, the accelerator opening (engine output torque) or the gear ratio of the toroidal continuously variable transmission changes from the time of release. Until the start, the passing torque changes according to only the force applied to the output shaft via the wheels.

  Thus, the force applied to the output shaft via the wheels is determined according to the road surface inclination and the total vehicle weight as described above. Of these, the total vehicle weight varies 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 the vehicle at that time can be set by a weight sensor, a load sensor, or the like. You can also find the total weight. In any case, the total vehicle weight can be obtained in this way. Therefore, if the change in the force applied to the output shaft is known before and after the operation of the braking device is released, the inclination of the road surface can be known. In the case of the present invention, the torque passing through the toroidal continuously variable transmission (passing torque), which changes according to the force applied to the output shaft, and thus the actuator, which changes according to the passing torque, The inclination of the road surface is determined on the basis of a difference in hydraulic pressure (differential pressure) between a pair of hydraulic chambers constituting the same.

  For example, when the vehicle is stopped, the shift lever is operated to the running state (a predetermined clutch device is connected), and the braking device is activated (for example, the brake pedal is depressed), the passing The torque or differential pressure has a value corresponding to a preset driving force (creep force) output from the output shaft. When the operation of the braking device is released from this state, the passing torque or the differential pressure changes according to the force applied to the output shaft via the wheels. In this case, for example, when the value of the passing torque or the differential pressure does not change, it is considered that the vehicle starts and travels at a low speed based on the creep force. In such a case, it is considered that the road surface on which the vehicle is located is an uphill with a gradient that allows the vehicle to start and run at a low speed even if the accelerator pedal is not depressed (by creep force).

  On the other hand, when the passing torque or the differential pressure is increased, the vehicle starts up more rapidly than when the passing torque or the differential pressure does not change, for example, when there is no depression of the accelerator pedal (only by the creep force). Even if it can be done, it is considered that the vehicle is only able to travel at a very low speed, or it is an uphill with such a gradient that it cannot start and remains stopped. On the contrary, when the passing torque becomes smaller, it is considered that the slope is gentler uphill, flat road, or downhill than when the passing torque or the differential pressure does not change. Furthermore, when the sign (sign) of the passing torque or differential pressure is reversed, the slope is steep downhill so that a force larger than the creep force can be applied to the output shaft in the same direction as the creep force. It is thought that.

  In the case of the present invention, the inclination of the road surface is determined based on such a relationship. For this reason, the inclination state of the road surface in the traveling direction of the vehicle can be obtained when the vehicle starts without using the inclination sensor. Then, depending on the inclination obtained in this way, for example, by adjusting the gear ratio of the toroidal-type continuously variable transmission or adjusting the engine output (accelerator opening), regardless of the road surface condition (for example, uphill) However, this can contribute to the smooth start of the vehicle. If such a smooth start operation can be realized, it is possible to secure a stable start feeling and to reduce fatigue when the driver starts on a hill.

  1 to 4 show an example of an embodiment of the present invention. The feature of this example is that between a pair of hydraulic chambers 32a and 32b (see FIG. 12) constituting the actuator 13 that changes according to the torque {that passes through the toroidal type continuously variable transmission 4 (see FIG. 11). Is based on the difference in hydraulic pressure between them (differential pressure)} to determine the inclination state of the road surface on which the vehicle incorporating the continuously variable transmission is located. Since the structure and operation of other parts are the same as those of the conventional structure shown in FIGS. 11 to 12 described above, overlapping illustrations and explanations are omitted or simplified, and the following description will focus on the characteristic parts of this embodiment. .

  In the case of this example, as in the conventional structure shown in FIGS. 11 to 12, the trunnions supporting the power rollers 12 by the hydraulic actuators 13 are provided in the axial directions of the pivots provided at both ends. To change the gear ratio between the input side disk 10 and the output side disk 11 (see FIG. 11). Further, a difference in hydraulic pressure (differential pressure) existing between a pair of hydraulic chambers 32a and 32b provided with the piston 31 sandwiched between the actuator 13 is determined by, for example, a pair of hydraulic sensors 36a and 36b (FIG. 12). (See below). A differential pressure between the hydraulic chambers 32a and 32b is obtained from the hydraulic pressure of the hydraulic chambers 32a and 32b detected by the hydraulic sensors 36a and 36b, and the continuously variable transmission is based on the differential pressure. The inclination state of the road surface on which the vehicle incorporating the vehicle is located is determined. That is, as shown in FIGS. 3 and 4, the differential pressure changes depending on the slope state (gradient) of the road surface when the brake pedal constituting the braking device is released when the vehicle starts. Specifically, this differential pressure (absolute value thereof) increases or decreases after the release of the depression of the brake pedal, or maintains the value as it is, or the sign (positive / negative) is reversed. In the case of this example, the road surface inclination state is determined based on such a change in the differential pressure. Note that the road surface inclination state determination means for making such a determination can be incorporated in an arithmetic unit constituting the controller 16 (see FIG. 11), for example.

The road surface inclination state determination operation performed by such road surface inclination state determination means will be described with reference to the flowchart shown in FIG. The work shown in this flowchart {determination of the starting road surface (STR_ROAD)} is repeatedly (automatically) performed from when the ignition switch is turned on until it is turned off.
First, in step 1, the arithmetic unit determines whether or not the gradient determination reference differential pressure (dP_BASE) has already been detected. The reference pressure difference for gradient determination (dP_BASE) is a value that is used as a reference when determining the final slope (gradient) of the road surface, as will be described later. More specifically, it refers to a value (average value) of a differential pressure generated based on a preset creep force (driving force) output from the output shaft 9 when the vehicle starts. In step 1, when it is determined that the reference pressure difference for gradient determination (dP_BASE) has not yet been detected, the determination of the starting road surface (STR_ROAD) is completed, and the gradient shown in the flowchart of FIG. The detection differential pressure reference (dP_BASE) is performed.

  The positive / negative sign of all differential pressures including the gradient determination reference differential pressure (dP_BASE) is such that the force (hydraulic pressure) applied in either direction with respect to the axial direction of the piston 31 constituting the actuator 13 becomes a positive value. It depends on whether it is a negative value. 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).

  In the operation of detecting the reference pressure for gradient determination (dP_BASE) shown in FIG. 2, first, in step 1, it is determined whether or not the vehicle is stopped, in other words, whether or not the vehicle speed is 0 km / h. This determination is made based on, for example, a signal from an output shaft rotation sensor 37 (see FIG. 11) for detecting the rotation speed of the output shaft 9 or a separately provided vehicle speed sensor. If it is determined in step 1 that the vehicle is not stopped, that is, the vehicle is traveling, the gradient determination reference differential pressure (dP_BASE) is not detected, and the operation is terminated ( Return to step 1). On the other hand, when it is determined that the vehicle is stopped, that is, the vehicle speed is 0 km / h, the driver moves the shift lever to the traveling state (D, L, R range) in the next step 2. It is determined whether or not it is operating. This determination is made by detecting whether or not the shift lever is in the forward position (D, L range) or the reverse position (R range) with the position switch 38 (see FIG. 11).

  If it is determined in step 2 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 gradient determination reference differential pressure (dP_BASE ) Is not performed, and the process ends (returns to step 1). On the other hand, when it is determined that the shift lever is operated in the traveling state, it is determined in the next step 3 whether or not the brake pedal is depressed. This determination is made based on, for example, an ON / OFF signal of the brake switch 39 (see FIG. 11). If it is determined in step 3 that the brake pedal has not been depressed, the gradient determination reference differential pressure (dP_BASE) is not detected, and the process ends (returns to step 1). On the other hand, if it is determined that the brake pedal is depressed, it is determined in next step 4 whether or not the depression of the accelerator pedal is released (released). This determination is made based on a signal from the accelerator sensor 40 (see FIG. 11).

  If it is determined in step 4 that the accelerator pedal is depressed, the operation for detecting the reference pressure difference for gradient determination (dP_BASE) is not performed, and the process ends (returns to step 1). On the other hand, if it is determined that the accelerator pedal is not depressed (released), it is determined in the next step 5 whether or not a predetermined time has elapsed. This predetermined time means that the clutch device 6 (low speed clutch 7) is connected by operating the shift lever to the traveling state, and a predetermined predetermined creep force (driving force) is stably set to the output shaft 9. The time until output can be performed (see FIG. 11), that is, the time until the differential pressure generated based on the creep force is stabilized. For example, referring to the diagrams of FIGS. 3 and 4, the shift lever is operated in the running state (D and L ranges in FIG. 3 and R range in FIG. 4), and the differential pressure rises to maintain a constant value. It takes about 1 to 2 seconds, for example, as the time until it becomes (time indicated by arrow t). If it is determined in step 5 that the predetermined time has not elapsed, the process returns to step 1 and the above operation is repeated again. On the other hand, if it is determined that the predetermined time has elapsed, the process proceeds to the next step 6. It should be noted that in step 5 above, instead of elapse of the predetermined time, the process waits for the next step 6 (return to step 1) until the value of the differential pressure detected by the hydraulic sensors 36a and 36b is stabilized. You can also do it.

  In any case, if it is determined in step 5 that the differential pressure based on the preset creep force is stable, the current differential pressure temp0 [kPa] is taken in as shown in step 6. . The differential pressure temp0 is taken in by the oil pressure sensors 36a and 36b. In the subsequent step 7, the average value (dP_AVE) of the differential pressure temp0 taken in this way is obtained. This average value (dP_AVE) is obtained, for example, as a moving average value read 10 times, more specifically, for example, a moving average value of differential pressure read 10 times every 10 ms (average value for 100 ms). The detection of the differential pressure for obtaining such an average value (dP_AVE) is performed within the time indicated by the arrow T in FIGS. Then, the average value (dP_AVE) of the differential pressure temp0 obtained in this way is set as a reference pressure difference (dP_BASE) for gradient determination in the subsequent step 8.

  As described above, the direction of the creep force, when the shift lever is operated to the forward position (D, L range) and when the shift lever is operated to the reverse range (R range), The direction of passing torque is reversed. Accordingly, the value of the gradient determination reference differential pressure (dP_BASE) obtained as described above also varies depending on the operation position of the shift lever. As described above, when operated to the forward position (D, L range) is negative (minus), the reference differential pressure for gradient determination in this case is set to dP_BASE_D, and operated to the backward position (R range). The case is positive (plus), and the reference differential pressure for gradient determination in this case is dP_BASE_R. The reference pressure difference (dP_BASE) for determining the gradient is about 300 [kPa] (275 to 325 [kPa]) when the vehicle weight is about 2 t (2000 kg), for example, dP_BASE_D. In the case of dP_BASE_R, it will be about +300 [kPa]. The reference pressure difference (dP_BASE) for gradient judgment differs depending on the preset creep force. For example, when this creep force is set to a large value, the absolute value also increases. Is also smaller. In addition, D or R in the * portion of dP_BASE_ * representing the gradient determination reference differential pressure indicates that it is dP_BASE (gradient determination reference differential pressure) if it is D. If there is, it is for showing that it is the value regarding the case of retreating. Subsequent terms are used in the same meaning.

  When the gradient determination reference differential pressure (dP_BASE) is obtained as described above, the process returns to the start road surface (STR_ROAD) determination operation of FIG. In step 1 of the determination operation of the starting road surface (STR_ROAD), the gradient determination reference differential pressure (dP_BASE) has already been detected as described above, and therefore the process proceeds to the subsequent step 2. In step 2, it is determined whether or not the driver is operating the shift lever in the traveling state, as in step 2 of the above-described detection operation of the gradient determination reference differential pressure (dP_BASE) in FIG. If it is determined in step 2 that the vehicle has not been operated in the running state (operated in the N and P ranges), the determination of the start road surface (STR_ROAD) is not performed, and the process ends (step 1). Return). On the other hand, when it is determined that the shift lever is operated in the traveling state (D, L, R range), the process proceeds to the next step 3. However, even when the shift lever is operated in the running state (D, L, R range), the operation position and the operation position when the above-described gradient determination reference differential pressure (dP_BASE) is detected. Are different from each other, the determination of the starting road surface (STR_ROAD) is not performed, and the process ends. In this case, the process returns to step 1 of the above-described gradient determination reference differential pressure (dP_BASE) detection operation, and the gradient determination reference differential pressure (dP_BASE) corresponding to the operation position is detected again.

  If the condition of step 2 as described above is satisfied, it is determined in the subsequent step 3 whether or not the depression of the brake pedal is released (released). If it is determined in step 3 that the brake pedal is depressed, the determination of the starting road surface (STR_ROAD) is not performed, and the process ends (returns to step 1). When the brake pedal is depressed in this way, the force from the wheels (force according to the vehicle weight and the road surface gradient) is not applied to the output shaft 9 of the continuously variable transmission, and the road surface inclination cannot be determined. It is. On the other hand, if it is determined that the brake pedal is released, it is determined in step 4 whether or not the accelerator pedal is released (released). If it is determined in step 4 that the accelerator pedal is depressed, the determination of the starting road surface (STR_ROAD) is not performed, and the process ends (returns to step 1). When the accelerator pedal is depressed in this way, the output from the engine 1 (see FIG. 11) changes, and the passing torque and thus the differential pressure is the force from the wheels applied to the output shaft 9 accordingly. This is because the change in the inclination of the road surface cannot be determined based on the above.

  On the other hand, when it is determined that the accelerator pedal is not depressed, the differential pressure is determined from the value indicated by point A in FIGS. 3 and 4 according to the force applied to the wheel (vehicle weight and road surface gradient). It can be judged that it starts to change according to the power. Therefore, in the following step 5, the degree of change in the differential pressure (dP_DEG) is determined. The degree of change in the differential pressure (dP_DEG) is expressed, for example, by whether or not the change rate of the differential pressure (change amount per unit time) exceeds a predetermined change rate (differential pressure change reference value). . For example, if the change rate (change amount) of the differential pressure exceeds a predetermined change rate (reference value), it is “changed quickly”, or conversely if it is less than the predetermined change rate (reference value), “slowly” It has changed. " Then, the degree of change in the differential pressure (dP_DEG) is determined (determining whether it has changed slowly or quickly) as follows.

  First, the change amount (dP_temp) of the differential pressure during a predetermined time (for example, 0.2 seconds) after it is determined that the depression of the brake pedal is released (from step 3) is obtained. Specifically, the absolute value of the difference between the reference pressure difference for gradient determination (dP_BASE) and the differential pressure (dP_NOW) after the lapse of the predetermined time (after 0.2 seconds) is obtained (dP_temp = | dP_BASE−dP_ NOW |). For example, when the shift lever is operated to the forward position (D, L range) under the above-mentioned conditions (vehicle weight is about 2t) (in the case of FIG. 3), the gradient determination reference differential pressure (dP_BASE_D) is If −300 [kPa] and the differential pressure (dP_NOW) after 0.2 seconds is −120 [kPa], the amount of change (dP_temp) is | dP_BASE_D −dP_ NOW | = | −300 − (− 120) | = 180 [kPa / 0.2 seconds]. Similarly, when the shift lever is operated to the reverse position (R range) (in the case of FIG. 4), the reference differential pressure for gradient determination (dP_BASE_R) is +300 [kPa], the differential pressure after 0.2 seconds If (dP_NOW) is +100 [kPa], the amount of change (dP_temp) is | dP_BASE_R−dP_Now | = | 300−100 | = 200 [kPa / 0.2 seconds].

  Then, the amount of change in differential pressure (dP_temp) obtained in this way is compared with the reference value for degree of change in differential pressure (dP_DEG_BASE). The differential pressure change degree reference value (dP_DEG_BASE) is obtained in advance by experiments, calculations, simulations, etc., and adjusted (tuned) to a preferable value for judging the road slope. When the amount of change (dP_temp) exceeds the reference value (dP_DEG_BASE), it is determined that the differential pressure has changed rapidly. Similarly, when the difference is not more than the reference value (dP_DEG_BASE), the differential pressure is Judge that it changed slowly. For example, when the above-mentioned conditions (vehicle weight is about 2 t) and the differential pressure change degree reference value (dP_DEG_BASE) is 100 [kPa / 0.2 seconds] (= 500 [kPa / seconds]), the above changes If the amount (dP_temp) is 180 [kPa / 0.2 seconds] or 200 [kPa / 0.2 seconds], it is determined that the differential pressure has changed rapidly. As will be described later, the differential pressure change degree reference value (dP_DEG_BASE) can be changed according to the result of determination of the differential pressure change direction (dP_DIRECT) in step 6 described below.

  As described above, if the degree of change in differential pressure (dP_DEG) is determined in step 5, then in step 6 the change direction of differential pressure (dP_DIRECT) is determined. The direction of change in differential pressure (dP_DIRECT) is determined by comparing the differential pressure after a predetermined time (for example, 1 second) after the release of the brake pedal and the reference differential pressure for gradient determination (dP_BASE). Whether or not the differential pressure is maintained (within a range of a predetermined value h), whether or not the absolute value of the differential pressure has increased or decreased, and the sign of the differential pressure ( This is done by determining whether (positive or negative) is reversed. For example, when the shift lever is operated to the forward position (D, L range) under the above-mentioned conditions (vehicle weight is about 2 t) (in the case of FIG. 3), the reference pressure difference (dP_BASE) for gradient determination is −300 [kPa] When the differential pressure after 1 second is within the range of −300 ± 75 [kpa] (in the case of the differential pressure indicated by the alternate long and short dash line α in FIG. 3), the differential pressure is maintained. judge. In addition, when the differential pressure after one second is −420 [kpa] under the same conditions (in the case of the differential pressure indicated by the long broken line β or the short broken line γ in FIG. 3), the absolute value of the differential pressure increased. Is determined. Conversely, when the differential pressure after 1 second is −120 [kpa] (in the case of the differential pressure indicated by the two-dot chain line δ or the three-dot chain line ε in FIG. 3), the absolute value of this differential pressure decreases. It is determined that Further, when the differential pressure after one second is +120 [kpa] under the same conditions (in the case of the differential pressure indicated by the solid line ζ in FIG. 3), it is determined that the differential pressure is reversed.

  On the other hand, when the shift lever is operated to the reverse position (R range) under the above-described conditions (vehicle weight is about 2 t) (in the case of FIG. 4), the reference differential pressure for gradient determination (dP_BASE) is +300. [kPa] If the differential pressure after 1 second is in the range of + 300 ± 75 [kpa] (in the case of the differential pressure indicated by the alternate long and short dash line α in FIG. 4), it is determined that this differential pressure is maintained. Also, if the differential pressure after one second is +400 [kpa] under the same conditions (in the case of the differential pressure indicated by the long broken line β or the short broken line γ in FIG. 4), the absolute value of the differential pressure has increased. judge. Conversely, when the differential pressure after 1 second is +100 [kpa] (in the case of the differential pressure indicated by the two-dot chain line δ or the three-dot chain line ε in FIG. 4), the absolute value of the differential pressure decreases. Is determined. If the differential pressure after one second is -100 [kpa] under the same conditions (in the case of the differential pressure indicated by the solid line ζ in FIG. 4), it is determined that the differential pressure is reversed.

If the degree of change in differential pressure (dP_DEG) is determined in step 5 described above, and the direction of change in differential pressure (dP_DIRECT) is determined in step 6 described above, the starting road surface (STR_ROAD) is determined in subsequent step 7. Judgment is made. The determination of the starting road surface (STR_ROAD) performed in step 7, that is, the determination of the slope (gradient) of the road surface on which the vehicle is located is performed based on Table 1 below.

  For example, when the degree of change in differential pressure (dP_DEG) is determined to be “slow change” in step 5 and the change direction of differential pressure (dP_DIRECT) is determined to be “maintained” in step 6, the start road surface (STR_ROAD) is determined to be a gentle uphill. That is, in such a case, the differential pressure is as indicated by a dashed line α in FIG. 3 when the shift lever is in the forward position, or as indicated by a dashed line α in FIG. , Each seems to have changed. In this case, it can be determined that the road surface is a gentle uphill. Specifically, the vehicle starts at a low speed with a preset creep force (for example, the vehicle speed changes as shown by a one-dot chain line η in FIGS. 3 and 4), for example, has a gradient of about 1 to 10%. It can be determined that the vehicle is uphill.

  On the other hand, when the difference (dP_DEG) in step 5 is determined to be “slow change” in step 5 and the pressure change direction (dP_DIRECT) is determined to be “increase” in step 6, the starting road surface ( STR_ROAD) is determined to be a slightly steep uphill. That is, in such a case, the differential pressure is as shown by the long broken line β in FIG. 3 when the shift lever is in the forward position, or as shown by the long broken line β in FIG. , Each seems to have changed. In this case, it can be determined that the road surface is a slightly steep uphill. Specifically, it can be determined that the slope is an uphill with a slope of about 10% to 15%, for example, which can travel only at a very low speed even if the vehicle can start with only a preset creep force.

  Further, when the degree of change in differential pressure (dP_DEG) is determined to be “rapid change” in step 5 and the direction of change in differential pressure (dP_DIRECT) is determined to be “increase” in step 6, the start road surface ( STR_ROAD) is determined to be a fairly steep uphill. That is, in such a case, the differential pressure is as indicated by the short broken line γ in FIG. 3 when the shift lever is in the forward position, or as indicated by the short broken line γ in FIG. It seems that it has changed. In this case, it can be determined that the road surface is a fairly steep uphill. Specifically, the vehicle cannot be started with only a preset creep force and remains stopped (the vehicle speed becomes the broken line θ in FIGS. 3 and 4), for example, an uphill with a gradient greater than 15%. It can be determined that there is.

  If the degree of change in differential pressure (dP_DEG) is determined to be “slow change” in step 5 and the differential pressure change direction (dP_DIRECT) is determined to be “decrease” in step 6, the starting road surface ( STR_ROAD) is determined to be a substantially flat road. That is, in such a case, the differential pressure is indicated by a two-dot chain line δ in FIG. 3 when the shift lever is in the forward position, or by a two-dot chain line δ in FIG. Like, it is thought that each changed. In this case, it can be determined that the road surface is a flat road, for example, a flat road within a range of uphill or downhill with a gradient of less than 1%. In this case, the vehicle starts and travels at a low speed by a preset creep force (for example, the vehicle speed changes as indicated by a one-dot chain line η in FIGS. 3 and 4).

  Further, when the degree of change in differential pressure (dP_DEG) is determined to be “change quickly” in step 5 and the direction of change in differential pressure (dP_DIRECT) is determined to be “decrease” in step 6, the starting road surface ( STR_ROAD) is determined to be a gentle downhill. That is, in such a case, the differential pressure is indicated by a three-dot chain line ε in FIG. 3 when the shift lever is in the forward position, or indicated by a three-dot chain line ε in FIG. Like, it is thought that each changed. In this case, it can be determined that the road surface is a gentle downhill, for example, a downhill with a gradient of about 1% to 10%.

  Further, when the degree of change in differential pressure (dP_DEG) is determined to be “change quickly” in step 5 and the direction of change in differential pressure (dP_DIRECT) is determined to be “reverse” in step 6, the start road surface ( STR_ROAD) is determined to be a steep downhill. That is, in such a case, the differential pressure is as indicated by the solid line ζ in FIG. 3 when the shift lever is in the forward position, or as indicated by the solid line ζ in FIG. It seems to have changed. In this case, the road surface can be determined to be a gentle and steep downhill, for example, a downhill having a slope of 10% or more. In this case, the vehicle starts with acceleration larger than the acceleration based on the preset creep force (for example, the vehicle speed changes as indicated by a solid line ι in FIGS. 3 and 4).

  When determining the starting road surface (STR_ROAD) in step 7 as described above, the differential pressure change degree reference value (dP_DEG_BASE) serving as a reference in determining the differential pressure change degree (dP_DEG) in step 5 is It can be changed according to the differential pressure change direction (dP_DIRECT) determined in step 6 above. For example, in the case of the above-described condition (vehicle weight is about 2 t), when the differential pressure change direction is determined to be “increase” in step 6, the differential pressure change degree reference value (dP_DEG_BASE) is set to 100 [ kPa / 0.2 sec] (= 500 [kPa / sec]), and if it is also judged to be “decrease”, it is also set to 20 [kPa / 0.2 sec] (= 100 [kPa / sec]). You can also do things. Also, a plurality of differential pressure change degree reference values (dP_DEG_BASE) can be set. For example, when the differential pressure change direction is determined to be “decrease” in step 6 under the above-described conditions (vehicle weight is about 2 t), for example, the first differential pressure change degree reference value (dP_DEG_BASE) is set to 100 [ kPa / sec], the second differential pressure change degree reference value (dP_DEG_BASE) is set to 200 [kPa / sec], and the third differential pressure change degree reference value (dP_DEG_BASE) is set to 800 [kPa / sec]. It is also possible to determine the differential pressure change degree (dP_DEG) with respect to each differential pressure change degree reference value (dP_DEG_BASE). In this way, when a plurality of reference values (dP_DEG_BASE) are set, the slope (gradient) of the road surface can be determined more finely. In any case, the main points are the vehicle weight (vehicle weight), the magnitude of preset creep force (driving force), the slope of the road surface (gradient), and the relationship between the slope of this road surface and the change in differential pressure. Thus, the differential pressure change degree reference value (dP_DEG_BASE) is set so that the determination of the slope of the road surface can be performed appropriately.

  FIGS. 5 to 10 show the change in differential pressure when the shift lever is operated in the forward direction (D range) for each road slope (gradient) in a vehicle (automobile) having a weight of 2 t (2000 kg). Yes. Of these, FIGS. 5 and 6 show changes in the case of an uphill with a slope of 9% (FIG. 5 and FIG. 6 differ in the operating state of the shift lever), and FIG. 7 shows the changes in the case of an uphill with a slope of 12%. FIG. 8 shows the change when the road is flat, FIG. 9 shows the change when the slope is 9% downhill, and FIG. 10 shows the change when the slope is 12% downhill. . As is apparent from such a diagram, the slope state (gradient) of the road surface on which the vehicle incorporating the continuously variable transmission is located can be determined based on the change in the differential pressure. In FIGS. 5, 7, 9, and 10, the vehicle speed changes from 0 km / h when the shift lever is operated from the N range to the D range, but the vehicle is not actually moving. This change in the vehicle speed is caused by a torsional vibration caused by a creep force applied to a rotating shaft (for example, an output shaft) for detecting the vehicle speed, and this vibration appears as the vehicle speed.

  The above description has been given of the case where the determination of the slope state (gradient) of the road surface is performed based on the differential pressure generated between a pair of hydraulic chambers constituting the actuator. However, this differential pressure changes according to the torque (passing torque) passing through the toroidal-type continuously variable transmission (having a correlation). Therefore, instead of the differential pressure, the road surface inclination state can be determined based on the passing torque (for example, by directly detecting the passing torque with a torque sensor or the like). Further, the case where a brake pedal (foot brake) is used as a braking device has been described as an example, but the same applies to a parking brake. That is, when the vehicle is started by releasing the parking brake without using the foot brake, the inclination state of the road surface may be determined based on the change in the differential pressure (passing torque) before and after the release. it can.

The flowchart which shows the operation | movement used as the characteristic of one example of embodiment of this invention. The flowchart for detecting the reference | standard differential pressure for gradient determination required in the determination operation | work of FIG. The diagram which shows the change of the differential pressure | voltage when operating a shift lever to a forward direction and releasing a brake. The diagram which shows the change of the differential pressure | voltage when operating a shift lever to a reverse direction and releasing a brake. The diagram which shows the change of the differential pressure in the uphill whose gradient is 9%. The diagram which similarly shows another example. The diagram which shows the change of the differential pressure in the uphill whose gradient is 12%. The diagram which shows the change of the differential pressure | voltage on a flat road. The diagram which shows the change of the differential pressure in the downhill whose gradient is 9%. The diagram which shows the change of the differential pressure in the downhill whose gradient is 12%. 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.

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 Line pressure control electromagnetic on-off valve 19 Solenoid valve 20 Shifting solenoid valve 21 Control valve device 22 Gear ratio control valve 23 Differential pressure cylinders 24a, 24b Correction control valve 25 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 31 Piston 32a, 32b Hydraulic chamber 34 Manual hydraulic switching valve 35 Pressure reducing valve 36a, 36b Hydraulic sensor 37 Output shaft rotation sensor 38 positive Switch 39 brake switch 40 accelerator sensor

Claims (11)

  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 the support members, and a gear-type differential unit that is a combination of a plurality of gears. In combination, the input shaft is rotated in one direction by the drive source by adjusting the gear ratio of the toroidal type continuously variable transmission and changing the relative displacement speed of the plurality of gears constituting the differential unit. In a continuously variable transmission that can convert the rotation state of the output shaft into forward rotation and reverse rotation with the stopped state remaining unchanged, the road surface on which the vehicle incorporating the continuously variable transmission is located Oblique state, the continuously variable transmission apparatus having a road inclination state determining means for determining based on the torque passing through the toroidal-type continuously variable transmission.   Each support member is displaced by a hydraulic actuator, and the road surface inclination state determination means changes according to the torque passing through the toroidal-type continuously variable transmission. The continuously variable transmission according to claim 1, wherein the slope state of the road surface is determined based on a difference in hydraulic pressure between the two.   The road surface inclination state determination means includes a torque immediately before the braking device is released on condition that the vehicle is stopped, the shift lever is in a traveling state, and the braking device is operating. The continuously variable transmission according to any one of claims 1 to 2, wherein the state of inclination of the road surface is determined based on a change in torque after the release.   The continuously variable transmission according to claim 3, wherein the road surface inclination state determining means determines that the road surface is uphill in the traveling direction when the torque does not change from a value immediately before the operation of the braking device is released. .   The road surface inclination state determination means is the case where the sign of the torque is not reversed from the value immediately before the release after the predetermined time has elapsed after the braking device is released, and the absolute value of the torque is released. The continuously variable transmission according to claim 3, wherein the road surface is determined to be an uphill with a greater inclination in the traveling direction than when the torque does not change when the value increases from the immediately preceding value.   The road surface inclination state determination means is the case where the sign of the torque is not reversed from the value immediately before the release after the predetermined time has elapsed after the braking device is released, and the absolute value of the torque is released. When the amount of change in torque increases from the immediately preceding value and exceeds a first predetermined amount of change set in advance, the road surface is more advanced than when the road surface is equal to or less than the first predetermined amount of change. The continuously variable transmission according to claim 5, wherein the continuously variable transmission is determined to be an uphill with a large inclination in a direction.   The road surface inclination state determining means determines that the road surface is flat or downhill in the traveling direction when the absolute value of the torque decreases from a value immediately before the operation of the braking device is released. The continuously variable transmission described.   The road surface inclination state determining means has a case where the absolute value of the torque is decreased from a value immediately before the operation of the braking device is released, and the change amount of the torque is equal to or less than a second predetermined change amount set in advance. The continuously variable transmission according to claim 7, wherein it is determined that the road surface is flat, and if the second predetermined amount of change is also exceeded, the road surface is determined to be downhill in the traveling direction.   The road surface inclination state determination means determines that the absolute value of the torque decreases from a value immediately before the braking device is released and the amount of change in the torque exceeds a preset third predetermined amount of change. The continuously variable transmission according to claim 7, wherein the road surface is determined to be a downhill having a larger inclination in the traveling direction than when the road surface is equal to or smaller than the third predetermined change amount.   The road surface inclination state determination means is the case where the sign of the torque is reversed after a predetermined time has elapsed since the braking device was released, and the torque change amount exceeds a preset fourth predetermined change amount. The continuously variable transmission according to claim 7, wherein the road surface is determined to be a downhill having a greater inclination in the traveling direction than when the road surface is equal to or smaller than the fourth predetermined amount of change.   The road surface inclination state determination means is a case where the sign of the torque is reversed after a lapse of a predetermined time after the operation of the braking device is released, and when the absolute value of the torque exceeds a preset first predetermined value, The continuously variable transmission according to claim 7, wherein it is determined that the road surface is a downhill having a greater inclination in the traveling direction than when the road surface is equal to or less than the first predetermined value.

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