JP4978131B2 - Continuously variable transmission - Google Patents

Description

  The present invention relates to an improvement of a continuously variable transmission incorporating a toroidal type continuously variable transmission, for example, used as an automatic transmission for a vehicle (automobile), and mode switching between a low speed mode and a high speed mode is unnecessarily repeated. This is to realize a structure that can prevent this.

  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. In addition, a continuously variable transmission that combines a toroidal continuously variable transmission and a planetary gear transmission in order to increase the fluctuation range of the gear ratio has been widely known, for example, as described in Patent Documents 3 to 6. It has been. Among them, Patent Document 3 discloses a mode in which power is transmitted only by a toroidal type continuously variable transmission (low speed mode) and a main power transmitted by a planetary gear type transmission which is a differential mechanism. There is described a continuously variable transmission having a mode (high-speed mode) that realizes a so-called power split state in which a transmission ratio is adjusted by a transmission. In Patent Documents 4 to 6, the so-called geared neutral state in which the rotation state of the output shaft can be switched between forward rotation and reverse rotation with the input shaft rotated in one direction can be realized. A continuously variable transmission with (low speed mode) is described.

  12 to 13 show continuously variable transmissions having a mode described in Patent Documents 5 to 6 that can realize a geared neutral state. Of these, FIG. 12 shows a block diagram of the continuously variable transmission, and FIG. 13 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 mechanism. 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. 13), 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. 13). 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.

  Further, the pressure oil discharged from the oil pump 27 (27a, 27b in FIG. 13) 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. 13) 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. 13). 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 provided with a piston sandwiched between the actuator 13 and the controller 16. The valve opening pressure is adjusted based on the introduction of the hydraulic pressure based on the opening / closing of the line pressure control electromagnetic opening / closing valve 18 controlled by the command. 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 a manual hydraulic pressure switching valve 31 and a pressure reducing valve 32, 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.

  FIG. 14 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 type continuously variable transmission 4 can be realized in the GN state as shown 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 the speed ratio of the toroidal continuously variable transmission 4 is increased as shown by the solid line β, The speed ratio of the continuously variable transmission as a whole can be increased (in the forward direction).

  In a vehicle incorporating a continuously variable transmission as described above, it is based on the driving state (driving condition) of the vehicle at that time, which is obtained from the operation of the accelerator pedal (accelerator opening) and the driving speed (vehicle speed) of the vehicle. 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.

  By the way, in the case of a continuously variable transmission having a low speed mode and a high speed mode, a toroidal type continuously variable transmission and a planetary gear type transmission are combined through a clutch device, the above-mentioned geared neutral state can be realized. Even if it is possible to realize the power split state described in Patent Document 3, mode switching between the low speed mode and the high speed mode is performed as follows. That is, this mode switching can realize the speed ratio of the continuously variable transmission that is adjusted according to the current running state (corresponding to the target speed ratio) in both the low speed mode and the high speed mode. It is performed in a state adjusted to a value {a value corresponding to the intersection point a of the solid line α representing the low speed mode and the solid line β representing the high speed mode in FIG. 14 (speed increase ratio is about 0.3)}. In this case, when viewed from the toroidal-type continuously variable transmission 4, the mode switching is adjusted in accordance with the current traveling state (corresponding target speed ratio). It is performed in a state where the ratio is a value corresponding to the above intersection point a and the value to be switched to the mode {mode switching point (rotation synchronization point), acceleration ratio is about 0.4 (maximum deceleration state)}. Is called.

For example, if the vehicle is traveling in the low speed mode, the gear ratio of the toroidal type continuously variable transmission 4 is reduced according to the current traveling state (corresponding to the target gear ratio) (the speed ratio of the continuously variable transmission). When the mode switching point (for example, 0.4 in the speed increasing ratio) is reached, the shift solenoid valve 20 is switched based on the control signal of the controller 16. Then, the high-speed clutch 8 that has been disconnected until then is connected, and the low-speed clutch 7 that has been connected so far is disconnected, and the low-speed mode is switched to the high-speed mode. On the other hand, if the vehicle is traveling in the high speed mode, the transmission ratio of the toroidal type continuously variable transmission 4 is reduced according to the current traveling state (corresponding to the target transmission ratio) (the speed ratio of the continuously variable transmission). When the mode switching point is reached, the shift solenoid valve 20 is switched based on the control signal of the controller 16. Then, the low-speed clutch 7 that has been disconnected until then is connected, and the high-speed clutch 8 that has been connected so far is disconnected, and the high-speed mode is switched to the low-speed mode.

  As described above, the mode switching is performed in a state where the gear ratio of the toroidal-type continuously variable transmission 4 that is adjusted according to the running state at that time is adjusted to the mode switching point (value to be switched). There is a need. However, both the mode switching from the low-speed mode to the high-speed mode and the mode switching from the high-speed mode to the low-speed mode are performed when the gear ratio of the toroidal-type continuously variable transmission 4 is the mode switching point (for example, the speed increasing ratio). If only 0.4 is reached, the mode switching may be repeated unnecessarily (control interference occurs) depending on the running state. For example, when the vehicle is traveling in the forward direction (between the GN point and the A point in FIG. 14) in the low speed mode while maintaining the accelerator opening (depressing amount of the accelerator pedal) at a certain value. When the traveling speed (vehicle speed) increases, the target gear ratio of the toroidal-type continuously variable transmission 4 changes to the deceleration side (point i side in FIG. 14) in order to increase the speed ratio of the continuously variable transmission. Then, based on the change in the target gear ratio, when the (actual) gear ratio of the toroidal continuously variable transmission 4 is decelerated and reaches the mode switching point (i) in FIG. Switch to high-speed mode.

  In such a case, for example, if the road is a flat road or a downhill road, the accelerator opening is maintained constant, so that the traveling speed of the vehicle further increases even after switching to the high speed mode. At the same time, in order to further increase the speed ratio of the continuously variable transmission, the speed ratio of the toroidal continuously variable transmission 4 is increased (departed) from the mode switching point. On the other hand, for example, in the case of an uphill road, depending on the slope of the slope road (gradient amount), the driving force output from the engine (drive source) and the travel applied to the vehicle immediately after switching to the high speed mode. The resistance {the sum of the forces (loads) that impede traveling such as rolling resistance, air resistance, gradient resistance, acceleration resistance, braking resistance, etc.} is substantially the same, and the traveling speed (vehicle speed) of this vehicle is There is a possibility of being maintained at a substantially constant value. In such a case, since the accelerator opening is constant, the target speed ratio obtained from the accelerator opening and the vehicle speed may vary with a slight change (increase / decrease) in the vehicle speed. is there. As the target speed ratio changes, the speed ratio of the toroidal-type continuously variable transmission 4 changes near the mode switching point, so that “low speed mode → high speed mode” and “high speed mode → low speed mode” This mode switching may be repeated unnecessarily (hunting occurs).

  In addition, while driving with a constant accelerator opening (for example, about 5%) on an ascending slope (while gently accelerating), for example, the driver intends to drive at a constant speed at the current vehicle speed and releases the depression of the accelerator pedal. Or it may be relaxed. In such a case, if the depression or relaxation of the accelerator pedal is immediately after the mode switching from the low speed mode to the high speed mode, for example, depending on the degree of increase in the vehicle speed, the toroidal continuously variable transmission may be There is a possibility that a gear ratio of 4 is maintained in the vicinity of the mode switching point. In such a case, the mode switching may be repeated unnecessarily, such as switching from the high speed mode to the low speed mode again, immediately after the mode switching to the high speed mode is performed. In addition, for example, on a downgraded road in a low speed mode and the accelerator opening is 0% (fully closed) or, for example, 1% (correction value) or less (less than the accelerator pedal is released) When the vehicle is traveling at a substantially constant speed, if the transmission ratio of the toroidal type continuously variable transmission 4 is in the vicinity of the mode switching point, mode switching is unnecessary as in the case described above. May be repeated. Such inconvenience is that the gear ratio of the toroidal continuously variable transmission 4 that is optimal for mode switching is one point, that is, the gear ratio that can be realized by the toroidal continuously variable transmission 4 (for example, the speed increasing ratio). 0.4 to 2.1) in which the speed ratio of the continuously variable transmission can be the same in both the high speed mode and the low speed mode (rotation synchronization point, for example, 0.4 in the speed increasing ratio). The fact that there is only one point is one of the causes.

  As a technique for preventing the mode switching as described above from being repeated unnecessarily, for example, those described in Patent Documents 7 and 8 are known. Among these, Patent Document 7 describes a technique for performing mode switching in a state where the transmission ratio of the toroidal type continuously variable transmission exceeds an optimum value (rotation synchronization point) for mode switching. However, when such a technique is adopted, even if it is possible to prevent the mode switching from being repeated unnecessarily, it is inevitable that the shift shock at the time of the mode switching becomes large. Japanese Patent Application Laid-Open No. H10-228561 describes a technique for setting each of the low speed clutch and the high speed clutch in a half-clutch state when the mode is switched. However, when such a technique is adopted, the absorption of the shift shock in the half-clutch state varies depending on the temperature or the like, so that the control may be complicated depending on conditions.

  On the other hand, Patent Document 9 discloses that gear shifting (shift up and shift down) is unnecessarily repeated in a stepped transmission having a stepped transmission mechanism (the gear ratio during travel cannot be adjusted steplessly). Techniques to prevent are described. That is, in the case of a vehicle incorporating a stepped transmission, an optimal shift stage (target shift stage) is obtained from the accelerator opening at that time and the vehicle speed, and control is performed to shift (shift up, shift down) to this shift stage. Has been done. Even in the case of such a stepped transmission, for example, in a driving state similar to the case where mode switching as described above is repeated unnecessarily (for example, when the accelerator opening is constant and the vehicle speed fluctuates), For example, the shift (shift up, shift down) may be repeated unnecessarily between the second speed and the third speed, or between the third speed and the fourth speed. In order to prevent such inconvenience, Patent Document 9 discloses a shift map (shift) having a “shift-up shift line (solid line)” and a “shift-down shift line (broken line)” as shown in FIG. A technique for performing shift control based on a shift map in which the relationship between the optimum shift stage and the vehicle speed differs between up and down is described. If such a technique is employed, for example, even if the vehicle speed slightly decreases after the upshift, the downshift is not performed immediately, and the current gear stage can be maintained until the vehicle speed decreases to some extent. For this reason, even when the vehicle speed fluctuates (increases / decreases) as described above, it is considered that shifting (shift up, shift down) can be prevented from being repeated unnecessarily.

  However, even when the shift map as shown in FIG. 15 is used, for example, when the accelerator opening is small and the vehicle is traveling at a low speed, the shift-up shift line and the shift-down shift line are used. (For example, h in FIG. 15). For this reason, when the vehicle is traveling in such a state, it is not possible to sufficiently prevent the gear shifting from being repeated unnecessarily with the fluctuation of the vehicle speed. Further, in the case of the continuously variable transmission as described above, the gear ratio is continuously changed in a stepless manner according to the accelerator opening and the vehicle speed. In contrast to being a mode switching point, the vehicle speed at which the mode switching is performed is infinite. For this reason, it is considered that the technology of the stepped transmission that limits the shift in relation to the vehicle speed as described above cannot be adopted as it is as a condition for mode switching of the continuously variable transmission. Even if it is adopted, it is difficult to sufficiently prevent the inconvenience as described above. For example, when the mode is switched from the low speed mode to the high speed mode, the vehicle speed at the time of the switching is stored, and an offset value (for example, a value obtained by subtracting “−5 km / h”) from the vehicle speed is stored. Set. As long as the vehicle speed does not become an offset value, it is conceivable that mode switching from the high speed mode to the low speed mode is not performed even when the transmission ratio of the toroidal continuously variable transmission reaches the mode switching point. However, in such a case, there is a possibility that the control becomes complicated, such as a condition for when the offset value is reset.

Japanese Patent No. 2734583 JP-A-5-39850 Japanese Patent Laid-Open No. 10-196759 JP 2003-307266 A JP 2004-225888 A JP 2004-211836 A JP-A-11-210872 Japanese Patent Laid-Open No. 2001-233502 JP-A-6-346953 Motoo Aoyama, "Bessed Best Car Red Badge Series 245 / A book that understands the latest mechanics of cars", Sanyusha Co., Ltd./Kodansha, Inc., 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 was invented to realize a structure capable of preventing the mode switching between the low speed mode and the high speed mode from being repeated unnecessarily.

Each of the continuously variable transmissions of the present invention is formed by combining a toroidal continuously variable transmission and a planetary gear type transmission via a clutch device, as in the case of conventionally known continuously variable transmissions.
Of these, the clutch device is connected when realizing the low speed mode for increasing the reduction ratio, and is disconnected when realizing the high speed mode for reducing the same, and when realizing the high speed mode. It comprises a high-speed clutch that is connected and disconnected when realizing the low-speed mode, and a controller that switches the connection / disconnection state of each clutch.
In addition, the controller has a function of setting the shift state to any one of the low speed mode and the high speed mode by controlling connection and disconnection of each clutch.
In particular, in the continuously variable transmission of the present invention, each of the controllers has a first function for determining whether or not to permit mode switching between the low speed mode and the high speed mode. It is
At the same time, the target speed ratio of the continuously variable transmission (optimal deceleration force or driving force is obtained based on at least the vehicle traveling speed and the accelerator opening, and the vehicle traveling state at that time. A second function for determining the target gear ratio of the toroidal continuously variable transmission corresponding to the target gear ratio and adjusting the gear ratio of the toroidal continuously variable transmission to the target gear ratio. ing.

In the case of the continuously variable transmission according to claim 1, it is determined whether or not the mode switching performed based on the first function is permitted. And the running resistance applied to the vehicle (the sum of the forces that impede the running on the vehicle, such as rolling resistance, air resistance, gradient resistance, acceleration resistance, braking resistance, etc.). The running resistance is obtained from, for example, a pure driving force output from the engine at that time and a state quantity (for example, acceleration) indicating the running state of the vehicle at that time. It can be obtained from the difference from the actual driving force (driving force including traveling resistance) estimated to be necessary to realize this traveling state.
Further, in the case of the continuously variable transmission according to claim 5, it is determined whether or not mode switching performed based on the first function is permitted. The ratio (the speed ratio of the entire continuously variable transmission corresponding to the ratio) and the target speed ratio determined by the second function (the target speed ratio of the entire continuously variable transmission corresponding to the ratio) are performed.

In the case of implementing the continuously variable transmission described in claim 1, preferably, the transmission ratio of the toroidal continuously variable transmission based on the second function is set in advance as described in claim 2. Even if the set value to be switched to the mode {for example, the maximum deceleration state (for example, the speed increase ratio is 0.46 or less)} is adjusted, if the running resistance at that time does not satisfy a predetermined condition {for example, in advance Unless the threshold value is larger or smaller than the set threshold value (the magnitude relationship varies depending on the direction of mode switching, etc.)}, the mode switching is not permitted.
Preferably, when the continuously variable transmission described in claim 5 is implemented, the transmission ratio of the toroidal continuously variable transmission is based on the second function as described in claim 6. Even if the preset mode switching value (eg, the speed increase ratio is 0.46 or less) is adjusted, the target corresponding to the current driving state when this mode switching is assumed. If the gear ratio does not become a predetermined value (for example, unless it becomes larger or smaller than a preset threshold value), mode switching is not permitted.

  In a state where such mode switching is not permitted, there is a possibility that the target speed ratio of the continuously variable transmission, which is obtained based on the running state at that time, becomes a value that cannot be realized in the current mode. In such a case, regardless of the target speed ratio, the speed ratio of the toroidal type continuously variable transmission is set to a value (for example, 0.46 or less as the speed increasing ratio) at which the preset mode switching should be performed. Keep it. Similarly, if the target speed ratio is a value that can be realized in the current mode, the speed ratio of the toroidal continuously variable transmission is adjusted to the target speed ratio corresponding to the target speed ratio (the current mode remains unchanged). Shift control is performed according to the running state at that time). On the other hand, if the mode switching is permitted, the connection / disconnection state of each of the low speed clutch and the high speed clutch is switched (mode switching is performed), and the target speed ratio (target gear ratio) corresponding to the traveling state at that time is set. Adjust (perform shift control according to the current running state in the switched mode).

  Preferably, when the continuously variable transmission described in claims 1 and 2 as described above is implemented, the mode switching from the low speed mode to the high speed mode is preferable as described in claim 3. The transmission is permitted on condition that the transmission gear ratio is adjusted to a preset value for switching the mode {for example, maximum deceleration state (speed increase ratio is 0.46 or less)}. On the other hand, mode switching from the high speed mode to the low speed mode is a value at which the speed change ratio of the toroidal continuously variable transmission is set in advance (for example, the speed increasing ratio is 0.46 or less). Even if it is adjusted, the driving resistance at that time is not permitted unless the predetermined condition is satisfied (for example, as long as it does not become larger than a preset threshold value).

  Preferably, when the continuously variable transmission described in claims 5 and 6 as described above is implemented, the mode switching from the low speed mode to the high speed mode is preferably performed as described in claim 7. The transmission is permitted on condition that the transmission gear ratio is adjusted to a preset value for switching the mode {for example, maximum deceleration state (speed increase ratio is 0.46 or less)}. On the other hand, mode switching from the high speed mode to the low speed mode is a value at which the speed change ratio of the toroidal continuously variable transmission is set in advance (for example, the speed increasing ratio is 0.46 or less). If the target gear ratio corresponding to the running state at that time does not reach a predetermined value when it is assumed that the mode switching to the low speed mode has been performed even if the speed is adjusted to 0 (for example, the speed increase ratio is 0. 0). Do not allow (unless it becomes greater than 58 or 0.58 or more).

  In the case of the continuously variable transmission according to claim 3 or claim 7 described above, the continuously variable transmission that is obtained based on the running state at that time in a state where mode switching to the low speed mode is not permitted. There is a possibility that the target speed ratio of the transmission becomes a value that cannot be realized in the current high speed mode. In such a case, regardless of the target speed ratio, the speed ratio of the toroidal type continuously variable transmission is set to a value (for example, 0.46 or less as the speed increasing ratio) at which the preset mode switching should be performed. Keep it. If the target speed ratio is a value that can be realized in the current high speed mode, the speed ratio of the toroidal type continuously variable transmission is adjusted to a target speed ratio corresponding to the target speed ratio (in the current high speed mode). The shift control according to the running state at that time is performed). On the other hand, if mode switching to the low speed mode is permitted, the low speed clutch is connected, the high speed clutch is disconnected, and the low speed mode is switched. Then, in the state of switching to the low speed mode in this way, the target speed ratio (target speed ratio) is adjusted according to the running state at that time (in the low speed mode, the shift control according to the running state at that time is performed. Do).

  Further, when the continuously variable transmission described in claims 5, 6 and 7 described above is implemented, it is preferable to control the target gear ratio of the toroidal continuously variable transmission as described in claim 8. The correlation between at least the vehicle speed, the accelerator opening, and the target gear ratio corresponding to the speed ratio of the continuously variable transmission required to obtain the optimum deceleration force or driving force is stored in advance in the machine. It calculates | requires based on the shift map to represent. The shift map is composed of a low speed mode shift map used in the low speed mode to which the low speed clutch is connected and a high speed mode shift map to be used in the high speed mode to which the high speed clutch is connected.

  In this case, as described in claim 9, the toroidal continuously variable transmission by the second function using the shift map corresponding to the mode at that time among the shift maps for the low speed mode and the high speed mode. Even if the gear ratio is adjusted to a preset value for switching the mode {for example, the maximum deceleration state (the speed increasing ratio is 0.46 or less)}, the mode switching is performed. If the target gear ratio corresponding to the driving state at that time obtained using the mode shift map to be adopted after mode switching does not reach a predetermined value (for example, set in advance) Do not allow mode switching unless it is greater or less than the threshold.

  More specifically, as described in claim 10, in the state of the high speed mode in which the speed ratio of the toroidal continuously variable transmission is adjusted by the second function using the high speed mode shift map, Even if the ratio is adjusted to a value to be switched to the low speed mode set in advance {for example, the maximum deceleration state (the speed increase ratio is 0.46 or less)}, at that time point determined from the low speed mode shift map If the target gear ratio corresponding to the driving state does not become a predetermined value (for example, unless the speed increase ratio is greater than 0.58 or 0.58 or more), the mode switching to the low speed mode is permitted. Try not to.

  In the case of implementing the continuously variable transmission described in claim 5, preferably, as described in claim 11, the transmission ratio of the toroidal continuously variable transmission is based on the second function. When the preset mode switching value {for example, maximum deceleration state (speed increase ratio 0.44 or less)} is adjusted, the toroidal type corresponding to the (current) traveling state at that time is adjusted. The relationship between the target transmission ratio of the step transmission and the current transmission ratio (actual transmission ratio) of the toroidal type continuously variable transmission at that time corresponds to the speed ratio of the entire continuously variable transmission. When the comparison is made, it is determined whether or not mode switching is permitted depending on whether or not a predetermined condition is satisfied. In other words, when the speed ratio of the continuously variable transmission as a whole is adjusted to a value for mode switching, the target speed ratio of the continuously variable transmission as a whole corresponding to the (current) traveling state at that time And the current speed ratio (actual speed ratio) of the entire continuously variable transmission (current speed ratio) at that time, and whether or not mode switching is permitted is determined depending on whether or not a predetermined condition is satisfied. Do.

  More specifically, as described in claim 12, during traveling in the low speed mode, the target gear ratio of the toroidal continuously variable transmission corresponding to the (current) traveling state at that time is determined at that time. When the speed ratio (actual speed ratio) of this toroidal type continuously variable transmission is compared with the speed ratio of the continuously variable transmission as a whole, it is on the deceleration side (shift down side) Therefore, the mode switching to the high speed mode is not permitted. In other words, while traveling in the low speed mode, the target speed ratio of the continuously variable transmission as a whole corresponding to the (current) traveling state at that time becomes the current (current) continuously variable transmission as a whole. When the speed is lower than the speed ratio (actual speed ratio) (increase ratio, actual speed ratio> target speed ratio), mode switching to the high speed mode is not permitted. For example, in the case of a continuously variable transmission that performs mode switching when the gear ratio of the toroidal continuously variable transmission is at a maximum deceleration state (for example, the speed increasing ratio is 0.46 or less), the target of the toroidal continuously variable transmission is When the speed ratio is on the speed increasing side with respect to the actual speed ratio (the speed increasing ratio, target speed ratio> actual speed ratio), the mode switching to the high speed mode is not permitted. On the contrary, in the case of a continuously variable transmission that performs mode switching when the transmission ratio of the toroidal continuously variable transmission is at the maximum speed increasing state, the target transmission ratio of the toroidal continuously variable transmission is the actual transmission ratio. On the other hand, when the speed is on the deceleration side (increase ratio, target gear ratio <actual gear ratio), mode switching to the high speed mode is not permitted.

  In other words, if the configuration described in claim 12 is reversed, as described in claim 13, the toroidal type corresponding to the (current) traveling state at the time when traveling in the low-speed mode. The target gear ratio of the continuously variable transmission is compared with the current (current) gear ratio of the toroidal continuously variable transmission (actual gear ratio) corresponding to the speed ratio of the continuously variable transmission as a whole. In this case, the mode switching to the high speed mode is permitted when the speed is the same or the speed increasing side (shift up side). In other words, while traveling in the low speed mode, the target speed ratio of the continuously variable transmission as a whole corresponding to the (current) traveling state at that time becomes the current (current) continuously variable transmission as a whole. When the speed ratio (actual speed ratio) is equal to or higher than the speed ratio (acceleration ratio, actual speed ratio ≦ target speed ratio), the mode switching to the high speed mode is permitted. For example, in the case of a continuously variable transmission that performs mode switching when the gear ratio of the toroidal continuously variable transmission is at a maximum deceleration state (for example, the speed increasing ratio is 0.46 or less), the target of the toroidal continuously variable transmission is When the speed ratio is the same as the actual speed ratio or on the deceleration side (increase ratio, target speed ratio ≦ actual speed ratio), the mode switching to the high speed mode is permitted. On the contrary, in the case of a continuously variable transmission that performs mode switching when the transmission ratio of the toroidal continuously variable transmission is at the maximum speed increasing state, the target transmission ratio of the toroidal continuously variable transmission is the actual transmission ratio. On the other hand, when the speed is the same or the speed increasing side (the speed increasing ratio, the target speed ratio ≧ the actual speed ratio), the mode switching to the high speed mode is permitted.

  Further, as described in claim 14, during traveling in the high speed mode, the target gear ratio of the toroidal type continuously variable transmission corresponding to the (current) traveling state at that time is the current (current) ) When the speed ratio (actual speed ratio) of the toroidal type continuously variable transmission is compared with the speed ratio of the continuously variable transmission as a whole, it is the speed increasing side (shift up side). Do not allow mode switching to low speed mode. In other words, when traveling in the high speed mode, the target speed ratio of the continuously variable transmission as a whole corresponding to the (current) traveling state at that time is the current speed of the continuously variable transmission as a whole (current). When the speed is higher than the speed ratio (actual speed ratio) (increase ratio, actual speed ratio <target speed ratio), the mode switching to the low speed mode is not permitted. For example, in the case of a continuously variable transmission that performs mode switching when the gear ratio of the toroidal continuously variable transmission is at a maximum deceleration state (for example, the speed increasing ratio is 0.46 or less), the target of the toroidal continuously variable transmission is When the speed ratio is on the speed increasing side with respect to the actual speed ratio (the speed increasing ratio, the target speed ratio> the actual speed ratio), the mode switching to the low speed mode is not permitted. On the contrary, in the case of a continuously variable transmission that performs mode switching when the transmission ratio of the toroidal continuously variable transmission is at the maximum speed increasing state, the target transmission ratio of the toroidal continuously variable transmission is the actual transmission ratio. On the other hand, when the speed is on the deceleration side (speed increase ratio, target speed ratio <actual speed ratio), mode switching to the low speed mode is not permitted.

  In other words, if the configuration described in claim 14 is reversed, as described in claim 15, the toroidal type corresponding to the (current) traveling state at that time during traveling in the high speed mode. The target gear ratio of the continuously variable transmission is compared with the current gear ratio of the toroidal continuously variable transmission (actual gear ratio) in correspondence with the speed ratio of the continuously variable transmission as a whole. In this case, the mode switching to the low speed mode is permitted when the same or the deceleration side (shift down side). In other words, when traveling in the high speed mode, the target speed ratio of the continuously variable transmission as a whole corresponding to the (current) traveling state at that time is the current speed of the continuously variable transmission as a whole (current). When the speed ratio (actual speed ratio) is the same as or slower than the speed ratio (acceleration ratio, actual speed ratio ≧ target speed ratio), the mode switching to the low speed mode is permitted. For example, in the case of a continuously variable transmission that performs mode switching when the gear ratio of the toroidal continuously variable transmission is at a maximum deceleration state (for example, the speed increasing ratio is 0.46 or less), the target of the toroidal continuously variable transmission is When the gear ratio is the same as the actual gear ratio or on the deceleration side (increase ratio, target gear ratio ≦ actual gear ratio), the mode switching to the low speed mode is permitted. On the contrary, in the case of a continuously variable transmission that performs mode switching when the transmission ratio of the toroidal continuously variable transmission is at the maximum speed increasing state, the target transmission ratio of the toroidal continuously variable transmission is the actual transmission ratio. On the other hand, when the speed is the same or the speed increasing side (speed increasing ratio, target speed ratio ≧ actual speed ratio), the mode switching to the low speed mode is permitted.

  Further, in the case of the continuously variable transmission according to claim 16, the determination as to whether or not mode switching as the first function is permitted is made based on the gear ratio of the toroidal type continuously variable transmission at that time, This is performed based on the accelerator opening (the amount by which the accelerator pedal is depressed), the operating condition of the braking device (the operating condition of the service brake, whether or not the brake pedal is depressed or the depressing force), and the traveling speed (vehicle speed) of the vehicle. Based on the second function, switching from the high speed mode to the low speed mode is a value at which the speed change ratio of the toroidal-type continuously variable transmission is set in advance (for example, the maximum deceleration state (speed increase ratio). Even when adjusted to 0.46 or less)}, the accelerator opening is 0% {or less than or equal to 1% (correction value) or less} (depressing the accelerator pedal is released) and the braking is performed. If the device is not activated (service brake is not activated, brake pedal depression is released), the vehicle traveling speed does not reach a predetermined value {for example, a predetermined value such as 17 km / h As long as the value is not smaller (slower) than the value, or is not lower than a predetermined value such as 17 Km / h}, it is not permitted. In other words, if it is considered that the accelerator pedal is not depressed but the driver does not intend to decelerate until the brake pedal is depressed, the gear ratio of the toroidal continuously variable transmission is preset. If the vehicle speed does not become a predetermined value (for example, 17 km / h) even if the speed is adjusted to a value to be switched (for example, 0.46 or less in the speed increasing ratio), the high speed mode is switched to the low speed mode. Does not allow mode switching.

In the case of the continuously variable transmission according to the present invention as described above, it is possible to prevent the mode switching from being repeated unnecessarily in any driving state without requiring a complicated configuration or control and with high reliability. The structure can be provided at a low price.
That is, whether or not mode switching is permitted is determined not only by the gear ratio (actual gear ratio) of the toroidal-type continuously variable transmission at that time, but also by this gear ratio and the state of travel at that time The travel resistance obtained from the amount (in the case of claim 1), or the target gear ratio (in the case of claim 5) according to the travel state at that time, or the accelerator opening, the operating condition of the braking device, and the vehicle Based on the traveling speed (in the case of claim 16). From the traveling resistance, it is possible to estimate the traveling state at that time, that is, how much the vehicle is decelerating, accelerating (accelerating), or traveling at a constant speed. Further, the traveling tendency of the vehicle can be estimated from the target gear ratio. Further, the driver's intention can be estimated from the accelerator opening, the operation of the braking device, and the traveling speed of the vehicle. For this reason, even when the transmission ratio of the toroidal type continuously variable transmission adjusted according to the target transmission ratio reaches the mode switching point, the estimated traveling state (traveling tendency, intention of the driver) By determining whether or not to allow mode switching according to the above, it is possible to prevent unnecessary mode switching such as returning to the original operation mode immediately after the mode switching is performed. In addition, a structure capable of preventing such inconvenience can be realized at low cost while ensuring reliability without requiring a complicated configuration or control.

[First example of embodiment]
1 to 3 show a first example of an embodiment of the present invention corresponding to claims 1 to 4 and 17. It should be noted that the feature of this example is that the mode switching is performed in order to prevent frequent mode switching even when the transmission ratio of the toroidal type continuously variable transmission 4 (see FIG. 12) is operated near the mode switching point. It is in the point which devised the judgment whether to permit or not. Since the structure and operation of the other parts are the same as those of the conventional structure shown in FIGS. 12 to 13 described above, the overlapping description will be 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 is set as shown in FIG. ing. Such setting is performed, for example, by regulating the reduction ratio of the planetary gear type transmission 5 or the like and the gear ratio of the transmission gear.

  Also in this example, as in the conventional structure shown in FIGS. 12 to 13, the reduction ratio is set by switching the connection / disconnection state of the low speed and high speed clutches 7 and 8 based on the control signal of the controller 16. A low speed mode (including a geared neutral state) to be increased and a high speed mode to reduce the reduction ratio are realized. For this reason, the connecting / disconnecting states of the low-speed and high-speed clutches 7 and 8 can be switched freely by the shift electromagnetic valve 20 whose energization state is controlled based on the control signal of the controller 16. Further, the controller 16 is supplied with detection signals from the input side and output side rotation sensors 33 and 34 and the output shaft rotation sensor 35, a detection signal from the accelerator sensor 36, a detection signal from the brake switch 37, and a position switch 38. Detection signal is input. Of these, the input side rotation sensor 33 measures the rotation speed of the input side disk 10, the output side rotation sensor 34 measures the rotation speed of the output side disk 11, and the output shaft rotation sensor 35 measures the rotation speed of the output shaft 9. To do. Based on the rotational speeds measured from the sensors 33, 34, and 35, the gear ratio of the toroidal-type continuously variable transmission 4 and the traveling speed (vehicle speed) of the vehicle are calculated. The accelerator sensor 36 detects the amount of depression of the accelerator pedal (accelerator opening). The brake switch 37 detects that the service brake (service brake, for example, foot brake) has been operated (the brake pedal has been depressed), and issues a signal indicating that. The position switch 38 generates a signal indicating the selected position of a shift lever (operation lever, select lever) provided in the driver's seat.

  The controller 16 to which detection signals from the sensors 33, 34, 35, 36 and the switches 37, 38 are input is the vehicle running speed detected from at least the output signal of the output shaft rotation sensor 35. (Vehicle speed) and a target speed ratio of the continuously variable transmission (travel at that time) based on the current travel state of the vehicle obtained from the accelerator opening detected from the output signal of the accelerator sensor 36. The target gear ratio of the toroidal continuously variable transmission 4 corresponding to the state) is determined, and the gear ratio of the toroidal continuously variable transmission 4 (and thus the speed ratio of the continuously variable transmission). Is adjusted to this target speed ratio (target speed ratio) (second function described in claims). The correlation between the vehicle speed and the accelerator opening (state quantity indicating the running state) and the target speed ratio (target speed ratio) is previously mapped in the memory of the controller 16 (for example, as shown in FIG. 5 described later). Map) and expressions. Then, using such a map (MAP) or expression, the target speed ratio (target speed ratio) corresponding to the state quantity (vehicle speed, accelerator opening, etc.) at that time is adjusted. The adjustment of the gear ratio of the toroidal type continuously variable transmission 4 (and hence the speed ratio of the entire continuously variable transmission) is driven by the stepping motor 17 in accordance with a control signal from the controller 16. In addition to switching the supply and discharge of hydraulic pressure to the actuator 13, the low-speed and high-speed clutches 7 and 8 are connected and disconnected based on the switching of the shift solenoid valve 20 as necessary (high speed and low speed modes). It is done by switching.

  In the case of this example, the controller 16 has a function for determining whether or not to allow mode switching between the low speed mode and the high speed mode (first function described in claims). It is Then, whether or not to permit the mode switching is determined by determining the gear ratio of the toroidal continuously variable transmission 4 at that time and the running resistance (rolling resistance, air resistance, gradient resistance) applied to the vehicle at that time. , Acceleration resistance, braking resistance, and the like, which is a sum of forces that impede travel applied to the vehicle). More specifically, based on the second function, the transmission ratio of the toroidal-type continuously variable transmission 4 is a value that should be set in advance, for example, the maximum deceleration state (the acceleration ratio is 0.46 or less). )}, If the running resistance at that time does not satisfy a predetermined condition (unless it is larger or smaller than a preset threshold corresponding to the direction of mode switching), the mode switching is permitted. I try not to.

This running resistance realizes this running state obtained from a pure driving force (T_ENGINE) output from the engine 1 at that time and a state quantity (for example, acceleration) representing the running state of the vehicle at that time. Therefore, it can be obtained from the difference from the actual driving force (T_VEHICLE) estimated to be necessary for this purpose (running resistance = T_ENGINE−T_VEHICLE). Of these, the pure driving force (T_ENGINE) is obtained from the following equation (1).
T_ENGINE = (Eng × A × Pme × F × i _CVT × 9.8) / (4π × R) [kgf] −−− (1)
Eng: Engine displacement [L: liter]
A: Transmission efficiency
Pme: Net average effective pressure [kgf / cm ² ]
F: Final reduction ratio = final gear ratio i _CVT : Speed ratio (reduction ratio) of the continuously variable transmission as a whole = Transmission gear ratio R: Tire dynamic load radius [m]
π: Pi ratio

  The transmission efficiency A is a predetermined constant. Further, 3.14 can be used as the circumference ratio π. Further, the engine displacement Eng, the final gear ratio F, and the tire dynamic load radius R are set according to the vehicle in which the continuously variable transmission is incorporated. Further, the net average effective pressure Pme can be obtained as a map corresponding to the rotation speed (rotation speed) of the engine 1 based on, for example, a catalog value of the mounted engine 1 and can be obtained using the map. When the net average effective pressure Pme is calculated by the engine controller 39 (engine controller, engine ECU) that controls the output of the engine 1, the value can be used (for example, acquired by communication). . It is also possible to receive fuel injection amount data from the engine controller 39 and calculate based on this data and the rotational speed (rotation speed) of the engine 1 at that time.

The actual driving force (T_VEHICLE) is a driving force that is estimated to be necessary to realize the traveling state of the vehicle at that time (including traveling resistance), and is obtained from the following equation (2).
T_VEHICLE = W x a / g [kgf]---(2)
W: Vehicle weight [kg]
a: Vehicle acceleration [m / s ² ]
g: Gravity acceleration [m / s ² ]
The vehicle weight W can be set according to the vehicle in which the continuously variable transmission is incorporated, and can also be detected by a load sensor provided in the vehicle. In addition to detecting the vehicle acceleration a by an acceleration sensor provided in the vehicle, the vehicle acceleration a can be estimated from the change speed of the vehicle speed at that time. The gravity acceleration g can be 9.8.

  The running resistance is calculated as the difference (T_ENGINE-T_VEHICLE) between the pure driving force (T_ENGINE) and the actual driving force (T_VEHICLE) as described above. Based on the running resistance thus obtained, The running state of the vehicle can be estimated. For example, referring to an example of the relationship between the pure driving force (T_ENGINE) of the engine 1 and the running resistance and the vehicle speed as shown in FIG. 2, the pure driving force (T_ENGINE) of the engine 1 is compared with the running resistance. In a large state (corresponding to the oblique lattice portion in FIG. 2 and the actual driving force (T_VEHICLE) is a positive value), it can be estimated that the vehicle is accelerating (accelerating). Further, it can be determined that the greater the value, the greater the degree of acceleration. On the other hand, in a state where the pure driving force (T_ENGINE) of the engine 1 is smaller than the running resistance (corresponding to the pear area in FIG. 2 and the actual driving force (T_VEHICLE) is a negative value), the vehicle is decelerating. Can be estimated. Further, it can be determined that the greater the value, the greater the degree of deceleration. Further, when the pure driving force (T_ENGINE) of the engine 1 and the running resistance are in balance (intersection point B, actual driving force (T_VEHICLE) is 0), it can be estimated that the vehicle is running at a constant speed.

  In any case, since the traveling state of the vehicle at that time can be estimated in this way, it is determined whether or not mode switching is permitted based on the traveling resistance. For example, consider a state in which the selected position of the shift lever is in the traveling state (D, L range) and the vehicle is traveling in the high speed mode. In this case, the speed ratio of the toroidal-type continuously variable transmission 4 that is adjusted according to the target speed ratio is a preset value for mode switching {for example, maximum deceleration state (speed increase ratio is 0.46 or less). } Is adjusted (decelerated) to determine whether to permit mode switching from the high speed mode to the low speed mode based on the running resistance. Specifically, using the map that represents the correlation between the running resistance, the rotational speed of the engine 1, and the threshold value for whether or not to allow mode switching, as shown in FIG. Whether or not the mode switching is permitted is determined based on whether or not the resistance is larger than this threshold value (a tuning value whose value changes according to the rotational speed of the engine 1). That is, if the running resistance is greater than the threshold value corresponding to the engine rotational speed at that time, the vehicle is greatly decelerated, and even if switching to the low speed mode, the original high speed mode is switched immediately after the switching. The possibility is considered low. In such a case, mode switching to the low speed mode is permitted. On the other hand, if the running resistance is equal to or less than the threshold value corresponding to the engine rotational speed at that time, the vehicle is not greatly decelerated, and when switching to the low speed mode, the original high speed mode is restored immediately after the switching. It is considered that there is a high possibility of switching. In such a case, mode switching to the low speed mode is not permitted.

  When the mode switching to the low speed mode is not permitted in this way, the target speed ratio of the continuously variable transmission determined based on the running state at that time may be a value that cannot be realized in the current high speed mode. There is sex. In such a case, regardless of the target speed ratio, the speed ratio of the toroidal-type continuously variable transmission 4 is set to the value at which the preset mode switching should be performed {maximum deceleration state (speed increase ratio is 0.00. 46 or less)}. If the target speed ratio is a value that can be realized in the current high speed mode, the speed ratio of the toroidal continuously variable transmission 4 is adjusted to a target speed ratio corresponding to the target speed ratio (current high speed mode). The shift control according to the running state at that time is performed). On the other hand, if mode switching to the low speed mode is permitted, the low speed clutch 7 is connected and the high speed clutch 8 is disconnected to switch to the low speed mode. Then, in the state of switching to the low speed mode, the speed is adjusted to the target speed ratio (target speed ratio) according to the running state at that time (shift control according to the current running state in the low speed mode is performed).

The function (first function) for determining whether to permit mode switching provided in the controller 16 as described above will be described with reference to the flowchart of FIG. The work shown in this flowchart is repeatedly (automatically) performed from when the ignition switch is turned on until it is turned off.
First, the controller 16 determines in step 1 whether or not the selected position of the shift lever is in a forward state (D, L range). This determination is made based on the detection signal of the position switch 38. If it is determined in step 1 that the selected position of the shift lever is not in the forward state {non-travel state (P, N range) or reverse state (R range)} (even in the reverse state) (Since the mode is not switched in the low speed mode), the process ends and returns to the start. On the other hand, if it is determined in step 1 that the selected position of the shift lever is in the forward state, it is determined in subsequent step 2 whether or not the vehicle is traveling, for example, the traveling speed of the vehicle is 1 km / h. It is determined whether the vehicle speed exceeds (current vehicle speed> 1 km / h). This determination is performed based on a detection signal of the output shaft rotation sensor 35 for detecting the rotation speed of the output shaft 9 that is proportional to the rotation speed of the wheel, for example. If it is determined in step 2 that the vehicle is not traveling (current vehicle speed ≦ 1 km / h), the process is terminated as it is (the low speed mode is not switched to the high speed mode). Go back to the start.

On the other hand, if it is determined in step 2 that the vehicle is traveling, the process proceeds to step 3 to determine the current traveling mode. Specifically, it is determined whether or not the current travel mode is the low speed mode. This determination is made based on the switching state of the shift solenoid valve 20 (the control signal of the controller 16 that controls). If it is determined in step 3 that the current travel mode is the low speed mode, the process proceeds to step 4. In this step 4, the current gear ratio (actual gear ratio, e _CVU ) of the toroidal-type continuously variable transmission 4 that is adjusted according to the target gear ratio is a preset value for mode switching {mode switching point It is determined whether or not (MP)} has been adjusted. This determination is made, for example, when the actual speed ratio (e _CVU ) obtained based on the detection signals of the input side and output side rotation sensors 33 and 34 is the maximum deceleration state (for example, the speed increase ratio is 0.46 or less, e _This can be done depending on whether or not _CVU ≦ 0.46). The mode switching point (MP) can be set to a maximum reduction ratio (for example, 0.46) which is designed from the dimensions of each part of the toroidal-type continuously variable transmission 4. Correction (adjustment) is made according to the magnitude of the torque (passing torque, transmission torque) that passes through the toroidal-type continuously variable transmission 4 at that time (shift from 0.46 to the acceleration side, 0.46 + correction value and You can).

In any case, in such step 4, the actual transmission ratio (e _CVU ) of the toroidal-type continuously variable transmission 4 is not adjusted to a preset value (MP) for mode switching (e _CVU > MP), the process ends and returns to the start. On the other hand, if it is determined in step 4 that the value (MP) to be switched to the mode is set (e _CVU ≦ MP), mode switching from the low speed mode to the high speed mode is permitted. That is, the process proceeds to step 5 where the high-speed clutch 8 is connected and the low-speed clutch 7 is disconnected by switching the shift solenoid valve 20. In the case of this example, the mode switching from the low speed mode to the high speed mode is performed only on the condition that the gear ratio of the toroidal-type continuously variable transmission 4 is adjusted to a preset value for mode switching. to approve. That is, it is not determined whether or not mode switching is permitted using the above-described running resistance. However, it is also possible to determine whether or not to permit mode switching from the low speed mode to the high speed mode using the running resistance and the gear ratio of the toroidal type continuously variable transmission. It is also possible to make a determination using other conditions.

On the other hand, if it is determined in step 3 that the current travel mode is the high speed mode, the process proceeds to step 6. In this step 6, the current gear ratio (actual gear ratio, e _CVU ) of the toroidal-type continuously variable transmission 4 adjusted according to the target gear ratio is a preset value for mode switching {mode switching point. It is determined whether or not (MP)} has been adjusted. This determination is performed in the same manner as in Step 4 described above. In such a step 6, it is determined that the actual transmission ratio (e _CVU ) of the toroidal-type continuously variable transmission 4 has not been adjusted to a preset value (MP) for mode switching (e _CVU > MP). If it is done, the process ends and returns to the start. On the other hand, if it is determined in step 6 that the mode switching value (MP) has been adjusted (e _CVU ≦ MP), the process proceeds to the next step 7 where the running resistance at that time is a predetermined value. It is determined whether or not the condition is satisfied. Specifically, depending on whether or not the above-described running resistance is larger than the threshold (P_PWR, solid line c) corresponding to the engine speed at that time as shown in FIG. 3 (running resistance> P_PWR), Make a decision. If it is determined in step 7 that the running resistance is equal to or less than the threshold (running resistance ≦ P_PWR), the mode switching from the high speed mode to the low speed mode is not permitted, and the process ends and returns to the start. . On the other hand, when it is determined that the running resistance is greater than the threshold (running resistance> P_PWR), mode switching from the high speed mode to the low speed mode is permitted. That is, the process proceeds to step 8 where the low-speed clutch 7 is connected and the high-speed clutch 8 is disconnected by switching the shift solenoid valve 20.

  In the case of this example as described above, whether or not to allow mode switching is determined not only by the gear ratio (actual gear ratio) of the toroidal-type continuously variable transmission 4 at that time, This is performed based on the running resistance obtained from the state quantity representing the running state at that time. From this running resistance, it is possible to estimate the running state at that time, that is, how much the vehicle is decelerating, accelerating (accelerating), or running at a constant speed. Depending on whether or not this running resistance exceeds a preset threshold value, unnecessary mode switching such as returning to the original operation mode again immediately after the mode switching is performed is repeated. It is possible to determine whether or not there is a high possibility that For this reason, even when the gear ratio of the toroidal-type continuously variable transmission 4 has reached the mode switching point, it is unnecessary by determining whether to permit mode switching based on the running resistance as described above. Repeating mode switching can be prevented. In addition, a structure capable of preventing such inconvenience can be realized at low cost while ensuring reliability without requiring a complicated configuration or control.

[Second Example of Embodiment]
4 to 5 show a second example of an embodiment of the present invention corresponding to claims 5 to 10 and 17. FIG. In the case of this example, the controller 16 determines whether to permit mode switching, the speed ratio of the toroidal-type continuously variable transmission 4 (see FIG. 12) at that time, and the travel at that time. It is configured so as to be performed based on the target gear ratio determined according to the state. More specifically, the speed ratio of the toroidal continuously variable transmission 4 adjusted according to the target speed ratio is a preset value for mode switching {mode switching point (MP), for example, maximum deceleration. State (speed increase ratio is 0.46 or less)}, the target gear ratio corresponding to the current traveling state in the case where it is assumed that the mode switching is performed must be a predetermined value. For example, unless it becomes larger or smaller than a preset threshold value, mode switching is not permitted.

  In the case of this example, the target gear ratio of the toroidal-type continuously variable transmission 4 is obtained on the basis of a shift map as shown in FIG. The shift map {corresponds to the rotational speed of the output shaft 9 (see FIG. 12) of the continuously variable transmission} is necessary to obtain the vehicle traveling speed (horizontal axis) and the optimum deceleration force or driving force. The correlation with the said target gear ratio (vertical axis | shaft) corresponding to the speed ratio of a step transmission is represented for every accelerator opening degree. Each line corresponding to the correlation between the traveling speed of the vehicle and the target gear ratio, which is represented for each accelerator opening degree, indicates that the low speed side (the left side in FIG. 5) sandwiches the mode switching point. Similarly, the high speed side (right side in FIG. 5) corresponds to the “high speed mode shift map” in the “low speed mode shift map”.

  In the case of this example, in the low speed mode state in which the low speed clutch 7 is connected and the high speed clutch 8 (see FIG. 13) is disconnected, the low speed mode shift map is used. The target gear ratio corresponding to the accelerator opening at the time and the traveling speed of the vehicle is obtained, and the gear ratio of the toroidal continuously variable transmission 4 is adjusted to the target gear ratio. On the other hand, in the high-speed mode state in which the high-speed clutch 8 is connected and the low-speed clutch 7 is disconnected, the accelerator opening at that time and the travel of the vehicle are determined using the high-speed mode shift map. The target gear ratio corresponding to the speed is obtained, and the gear ratio of the toroidal continuously variable transmission 4 is adjusted to the target gear ratio.

  In the case of this example in which the speed ratio of the toroidal type continuously variable transmission and the speed ratio of the continuously variable transmission are controlled using the speed change map as described above, it is determined whether or not mode switching is permitted. This is performed based on the actual transmission ratio of the toroidal type continuously variable transmission and the target transmission ratio obtained from the transmission map. That is, in the state where the gear ratio of the toroidal continuously variable transmission 4 is adjusted using the shift map corresponding to the mode at that time among the shift maps for the low speed mode and the high speed mode. It is assumed that this mode switching is performed even if the ratio is adjusted to a preset value (mode switching point (MP), for example, maximum deceleration state (up to 0.46 in speed increase ratio)) at which mode switching should be performed. In this case, if the target gear ratio corresponding to the driving state at that time obtained by using the mode shift map to be adopted after the mode switching does not become a predetermined value {for example, it is increased from the mode switching point (MP). As long as the speed-side value, for example, the speed increase ratio is not larger than 0.58}, mode switching is not permitted.

Also in the case of this example configured as described above, as shown in Steps 3 to 5 in FIG. 4, the mode switching from the low speed mode to the high speed mode is performed in the same manner as in the above-described first example. Only when the gear ratio is adjusted to a preset value {mode switching point (MP), for example, the maximum deceleration state (the acceleration ratio is 0.46 or less)} for mode switching. On the other hand, the mode switching from the high speed mode to the low speed mode is performed in step 6 by using the high speed mode shift map, and the gear ratio of the toroidal continuously variable transmission 4 is preset. Even if it is determined that the value has been adjusted to a value for switching the mode (for example, 0.46 or less in the speed increasing ratio), it is not permitted if the target speed ratio becomes a predetermined value. That is, as shown in step 7, unless the target gear ratio corresponding to the current traveling state obtained from the low speed mode shift map is a predetermined value (for example, the speed increase ratio is larger than 0.58). (In other words, unless the current driving force is lower than the target driving force), mode switching from the high speed mode to the low speed mode is not permitted (does not proceed to step 8). The predetermined value may be set to an optimum value obtained in advance through experiments, simulations, or the like, or may be a tuning value that adjusts the value according to the running state at that time.
Other configurations and operations are the same as those in the first example described above (except for step 7, the same operations as those in the flowchart shown in FIG. 1 of the first example are performed), and redundant description is omitted.

[Third example of embodiment]
FIG. 6 shows a third example of an embodiment of the present invention corresponding to claims 16 and 17. In the case of the second example described above, as long as the target gear ratio does not satisfy a predetermined condition, the target gear ratio is a value on the speed-increasing side to some extent from the mode switching point (for example, 0.46 in the speed increasing ratio) Unless the speed ratio is 0.58), the mode switching is not permitted. In the case of this second example, it is possible to sufficiently prevent mode switching from being repeated unnecessarily, but depending on the driver's operation status and road surface conditions, this mode switching not intended by the driver (high speed Mode switching from the mode to the low speed mode) is performed, which may give the driver a sense of incongruity. That is, for example, a state is considered in which the driver depresses or relaxes the accelerator pedal so that the driver intends to travel at a constant speed while traveling in a high speed mode {with a small accelerator opening (for example, about 5 to 10%)}. In such a case, for example, if the road surface condition is such that the vehicle traveling speed does not decrease, such as a flat road or a downhill, the speed ratio of the toroidal continuously variable transmission 4 is a value (mode switching point) at which mode switching should be performed. , MP), the target speed change ratio does not change so much (does not exceed 0.58), so the mode switching from the high speed mode to the low speed mode is not performed (mode switching is repeated unnecessarily). Can be prevented).

  However, in the case where the traveling speed of the vehicle decreases due to the road surface condition such as an uphill road, the target gear ratio satisfies a predetermined condition as the speed decreases (becomes 0.58 or more). ) There is a possibility that mode switching from the high speed mode to the low speed mode may be performed. In such a case, since the driver intends to run at a constant speed, this mode switching may give a sense of incongruity. When such mode switching is performed, for example, if the driver continues to depress the accelerator pedal even a little (for example, 1% or more), it is considered that the driver intends to accelerate. Even if the mode is switched from a high speed mode to a low speed mode, it does not feel strange (it seems to be a downshift necessary for acceleration). On the other hand, for example, when the accelerator pedal depression is (completely) released (released) immediately after the mode is switched from the low speed mode to the high speed mode, the mode accompanying the decrease in the vehicle speed (vehicle speed) as described above. When switching (high speed mode → low speed mode) is performed, the driver may feel uncomfortable and may interfere with constant speed travel. A state where such inconvenience occurs will be described in more detail with reference to FIG.

FIG. 7 shows a shift map for each of the low speed mode and the high speed mode (solid lines α _L and α _H ) in the vicinity of the mode switching point (for example, corresponding to part A in FIG. 5), FIG. 4 shows an example of low speed mode and high speed mode shift maps (chain lines β _L and β _H ) with an accelerator opening of 5%. For example, if the vehicle speed reaches 20 km / h while driving in the low speed mode and the accelerator opening is 5% (slowly accelerating), for example, according to the low speed mode shift map (solid line β _L ). The speed ratio of the toroidal type continuously variable transmission 4 adjusted in this way reaches the mode switching point (point a in FIG. 7), and the mode switching from the low speed mode to the high speed mode is performed. Then, consider a case where the accelerator pedal is completely depressed immediately after the mode switching. In this case, the target speed change ratio obtained from the low speed mode speed change map (solid line α _L ) with the accelerator opening being 0%, for example, must be greater than 0.58 (point b in FIG. 7) as the speed increase ratio. For example, mode switching from the high speed mode to the low speed mode is not performed. However, as described above, when the vehicle speed decreases after the accelerator pedal is released, the vehicle speed immediately reaches a vehicle speed (for example, 19 km / h) corresponding to the above speed increase ratio of 0.58 (point b in FIG. 7). Therefore, there is a possibility that the mode is switched from the high speed mode to the low speed mode.

  In order to prevent such an inconvenience, when the accelerator opening is 0% or less, the amount of change in the target gear ratio due to the change in vehicle speed is reduced, that is, the distance between points a and b in FIG. It is conceivable to increase k (increase hysteresis). More specifically, it is conceivable to change the low speed mode shift map with the accelerator opening being 0% to, for example, the broken line γ in FIG. However, in such a case, even if it is possible to prevent the mode switching from the high speed mode to the low speed mode as described above, there is an unfavorable influence such as a delay in mode switching timing during acceleration in the low speed mode. There is a possibility of effect. Further, when the accelerator opening is 0%, it may be possible to use different low-speed mode shift maps for acceleration and deceleration, but the control may be complicated.

  On the other hand, in the case of this example, in order to prevent the above-described inconvenience, it is determined whether or not to permit mode switching from the high speed mode to the low speed mode. Based on the gear ratio of the machine 4, the accelerator opening (depressing the accelerator pedal), the operating condition of the braking device (braking device) (the operating condition of the service brake, the depressing condition of the brake pedal), and the traveling speed of the vehicle It is configured to do. More specifically, the gear ratio of the toroidal-type continuously variable transmission 4 is adjusted to a preset value for mode switching (mode switching point, MP, for example, the speed increasing ratio is 0.46 or less). However, the accelerator opening is 0% {or less than or equal to 1% (correction value) or less} (the accelerator pedal is released) and the braking device is not activated (service brake is activated) (If the brake pedal is not released), the vehicle speed must be at the predetermined value (P_SPD) (for example, unless it is less than 17 km / h). The mode switching to the low speed mode is not permitted. In other words, when the depression of the accelerator pedal is released, but it is considered that the driver does not intend to decelerate until the brake pedal is depressed, the transmission ratio of the toroidal continuously variable transmission 4 is set in advance. If the vehicle speed does not become a predetermined value (for example, 17 km / h) even if it is adjusted to a set value for mode switching (for example, 0.46 or less in the speed increasing ratio), the high speed mode is changed to the low speed mode. The mode switching to is not permitted.

  The accelerator opening is not 0% {or less than 1% (correction value) or less} (the accelerator pedal is depressed), or the brake device is not activated (the brake pedal is depressed). If, for example, as in the first or second example described above, it is determined whether or not to allow mode switching based on the running resistance or the target gear ratio at that time. The predetermined value (P_SPD) of the traveling speed for determining the mode switching is, for example, a value for switching the mode from the high speed mode to the low speed mode when the accelerator opening is 0% or a threshold value (for example, the speed increasing ratio). The engine speed is smaller than the vehicle speed corresponding to 0.46 to 0.58) (for example, 19 to 20 km / h) and the toroidal continuously variable transmission 4 has a gear ratio of the mode switching point (MP). Set the speed within the range of vehicle speed that does not cause knocking phenomenon (unstable rotation). The predetermined value (P_SPD) can also be adjusted according to the vehicle condition at that time (during sudden / slow deceleration, magnitude of deceleration acceleration, oil temperature level, shift mode, etc.).

  The determination operation of whether or not to permit mode switching from the high speed mode to the low speed mode, which is a feature of this example, will be described with reference to the flowchart of FIG. In the flowchart of FIG. 6, the same number of steps as those in FIGS. 1 and 4 are given to the steps for performing the same operations as those in the flowcharts shown in FIGS. 1 and 4 in the first and second examples. . For this reason, the description of the parts with the same number of steps is omitted, and hereinafter, the work (characterized by the broken line in FIG. 6, mainly steps 9 to 11) which is the feature of this example. I will explain.

In step 3, the current travel mode is determined to be the high speed mode, and in step 6, the current speed ratio (actual speed ratio, e _CVU ) of the toroidal continuously variable transmission 4 adjusted according to the target speed ratio is If it is determined that the mode has been adjusted to a preset mode switching point (for example, 0.46 in speed increasing ratio) or less, the routine proceeds to step 9. In this step 9, the accelerator opening is 0% (ACCEL = 0%) {or less than 1% (correction value) (ACCEL <1%)} (accelerator pedal depression is released). Determine whether. This determination is made based on, for example, a detection signal from the accelerator sensor 36 (see FIG. 12). If it is determined in step 9 that the accelerator opening is not 0% (the accelerator pedal is depressed, for example, ACCEL ≧ 1%), the process proceeds to step 7. This step 7 corresponds to step 7 (FIGS. 1 and 4) of the first example or the second example described above, and whether or not mode switching is permitted depending on the running resistance or the target gear ratio at that time. Judgment is made.

  On the other hand, if it is determined in step 9 that the accelerator opening is 0% (ACCEL = 0%) {or, for example, less than 1% (correction value) (ACCEL <1%)}, Proceeding to 10, it is determined whether or not the braking device is not operating (service brake is not operating, brake pedal depression is released, BRAKE = OFF). This determination is performed based on, for example, a detection signal from the brake switch 37 (see FIG. 12). If it is determined in step 10 that the braking device is operating (BRAKE = ON), the process proceeds to step 7. This step 7 is as described above. On the other hand, if it is determined in step 10 that the braking device is not operating (BRAKE = OFF), the process proceeds to step 11. In this step 11, it is determined whether or not the current vehicle traveling speed is decreasing {for example, smaller (slower) than 17 km / h, or vehicle speed <P_SPD (= 17 km / h)}.

This determination is performed based on, for example, a detection signal from the output shaft rotation sensor 35 (see FIG. 12) for detecting the rotation speed of the output shaft 9 proportional to the rotation speed of the wheel. If it is determined in step 11 that the traveling speed has not decreased {for example, it is 17 km / h or more (fast)}, the process ends and returns to the start. On the other hand, when it is determined in step 11 that the travel speed is decreasing {eg, smaller than (slower) than 17 km / h}, mode switching from the high speed mode to the low speed mode is permitted. That is, the process proceeds to step 8 where the low-speed clutch 7 is connected and the high-speed clutch 8 (see FIG. 13) is disconnected by switching the shift solenoid valve 20.
Other configurations and operations are the same as those in the first and second examples described above, and thus redundant description is omitted.

  Although illustration is omitted, if necessary, it is determined whether or not to change the mode from the low speed mode to the high speed mode. The speed ratio of the toroidal continuously variable transmission at that time and the accelerator opening degree are determined. And based on the operation of the braking device and the speed of the vehicle. For example, even when the mode switching from the low speed mode to the high speed mode is adjusted to a value at which the speed change ratio of the toroidal type continuously variable transmission should be set in advance, the accelerator opening is 0% ( Or less than 1%), and when the braking device is not operating, the vehicle may not be permitted unless the traveling speed of the vehicle reaches a predetermined value.

[Fourth Example of Embodiment]
8 and 9 show a fourth example of an embodiment of the present invention corresponding to claims 5, 11 to 15 and 17. Prior to the description of these examples shown in FIGS. 8 and 9, the mode switching control (preceding example) considered by the inventor prior to this example will be described with reference to FIG. The background of the preceding example shown in FIG. 10 is as follows. That is, as described above, mode switching is performed when the gear ratio of the toroidal-type continuously variable transmission is a value at which mode switching should be performed {mode switching point (rotation synchronization point), speed increasing ratio, for example, 0.46 or less (maximum deceleration state) )} Is necessary to be performed. In this case, if the mode is switched from the current mode (for example, the low speed mode) to the next mode (for example, the high speed mode) simply on the condition that the mode switching point (rotation synchronization point) is adjusted, the following is performed. May cause inconvenience. That is, at the moment when this switching is completed, the gear ratio of the toroidal continuously variable transmission is still adjusted to the mode switching point (rotation synchronization point). Mode). In other words, since there is no hysteresis at the mode switching point (only the rotation synchronization point), if other vehicle conditions relating to mode switching are improperly set, hunting “low (low) mode → high speed is achieved by this mode switching. (High) mode → low speed (low) mode → high speed (high) mode... Repeated ”may occur, which may hinder stable driving.

Therefore, in order to prevent such inconvenience, while driving in the current mode (for example, low speed mode), the “accelerator opening (for example, accelerator pedal operation status)”, “vehicle speed (vehicle speed)”, “braking device Based on the operation (for example, the operation state of the brake pedal), etc., it is considered that the driving operation state of the driver (driver) is determined and permission / prohibition of switching to the next mode (for example, the high speed mode) is considered. Specifically, for example, when traveling in the low speed mode, the following determination is made according to the accelerator opening and the operation of the braking device.
(1) Depressing the accelerator pedal and releasing without depressing the brake pedal: The driver intends to accelerate → Permits mode switching from “low speed mode to high speed mode”.
(2) Opening without depressing the accelerator pedal: The driver does not intend to accelerate → prohibit mode switching from “low speed mode to high speed mode”.
On the other hand, if the vehicle is traveling in the high speed mode, for example, the following determination is made according to the accelerator opening and the operation of the braking device.
(3) Releasing without depressing the accelerator pedal and depressing the brake pedal: The driver intends to decelerate → Permits mode switching from “high speed mode to low speed mode”.
(4) Depressing the accelerator pedal: The driver does not intend to decelerate → prohibit mode switching from “high speed mode to low speed mode”. However, mode switching from “high speed mode to low speed mode” is permitted in a state where the accelerator pedal is depressed and a large acceleration is required, such as during kickdown acceleration.

FIG. 10 shows a flowchart for permitting / inhibiting mode switching while making the above-described determination. The operation shown in this flowchart is also repeatedly (automatically) performed from when the ignition switch is turned on until it is turned off. Steps 1 to 3 are the same as the first to third examples of the embodiment described above. After step 3, it is determined whether or not the mode is switched as follows.
If it is determined in step 3 that the current travel mode is the low speed mode, the process proceeds to step 4 to determine whether or not the accelerator opening exceeds 1% (ACCEL> 1%). It is determined whether or not the pedal is depressed. If it is determined in step 4 that the accelerator pedal is not depressed (NO), that is, it is determined that the accelerator pedal is released, it can be determined that the driver has no intention to accelerate. The process proceeds and ends while maintaining the low speed mode (without switching to the high speed mode) and returns to the start.

  On the other hand, if it is determined in step 4 that the accelerator pedal is depressed (YES, the accelerator opening exceeds 1%), the brake device is not operated in step 6 (BRAKE). = OFF), that is, whether or not the brake pedal is released is determined. If it is determined in step 5 that the brake pedal is not released (NO, the pedal is depressed), the process proceeds to step 5 above, and the low speed mode is maintained (without switching to the high speed mode). End and return to start. In this case, both the accelerator pedal and the brake pedal are depressed, and a driver's erroneous operation or failure may be considered. Therefore, it is also possible to take measures according to that.

On the other hand, if it is determined in step 6 that the brake pedal is released (YES), then in step 7, the toroidal continuously variable transmission 4 that is adjusted according to the target gear ratio (see FIG. 12). current speed change ratio) (actual speed ratio, e _CVU) is preset mode switching value should do {mode switching point (MP), for example at the maximum deceleration state (e.g. speed increasing ratio 0.46, e _CVU ≦ 0.46)} is determined. In step 7, it is determined that the actual transmission ratio (e _CVU ) of the toroidal-type continuously variable transmission 4 has not been adjusted to a preset value (MP) for mode switching (e _CVU > MP). In such a case, the process proceeds to the above step 5 and ends while maintaining the low speed mode (without switching to the high speed mode) and returns to the start. On the other hand, if it is determined in step 7 that the value (MP) to be switched to mode is adjusted (e _CVU ≦ MP), the process proceeds to step 8 to switch the mode from the low speed mode to the high speed mode. Allow (and return to start via end).

On the other hand, if it is determined in step 3 that the current travel mode is the high speed mode, the process proceeds to step 9. In Step 9, it is determined whether or not the accelerator opening is 1% or less (ACCEL ≦ 1%), that is, whether or not the accelerator pedal is released. If it is determined in step 9 that the accelerator pedal is released (YES), the process proceeds to step 10 where the brake device is operated (BRAKE = ON), that is, whether the brake pedal is depressed. Determine whether or not. If it is determined in step 10 that the brake pedal is depressed (YES), the process proceeds to step 11. In this step 11, the current gear ratio (actual gear ratio, e _CVU ) of the toroidal-type continuously variable transmission 4 is a preset value for mode switching {mode switching point (MP), for example, speed increasing ratio. It is determined whether it is adjusted to 0.46 or less and e _CVU ≦ 0.46}. If it is determined in step 11 that the value (MP) for the mode switching is adjusted (e _CVU ≦ MP), the process proceeds to step 12 to switch the mode from the high speed mode to the low speed mode. (And return to start via end). On the other hand, if it is determined in step 11 that the value (MP) to be switched to is not adjusted (e _CVU > MP), the process proceeds to step 13 and the high speed mode is maintained (low speed mode). (Without switching to) and return to the start.

On the other hand, if it is determined in step 9 that the accelerator pedal is depressed (NO), the process proceeds to step 14 and whether or not the accelerator opening exceeds 80% (ACCEL> 80%). That is, it is determined whether or not the driver requests kickdown acceleration. If it is determined in step 14 that the accelerator opening is equal to or less than 80% (NO), the process proceeds to step 13 and ends while maintaining the high speed mode (without switching to the low speed mode). Go back to the start. On the other hand, when it is determined in step 14 that the accelerator opening exceeds 80% (YES, requesting kickdown acceleration), the process proceeds to step 11 and a toroidal stepless The mode switching from the high speed mode to the low speed mode is permitted on condition that the current speed ratio (actual speed ratio, e _CVU ) of the transmission 4 is adjusted to a value (MP) to be switched.

If it is determined in step 10 that the brake pedal is released (the braking device is not operated), the process proceeds to step 15 and the third example of the above-described embodiment (FIG. 6). In the same manner as in step 11, it is determined whether or not the current vehicle traveling speed is decreasing {for example, smaller than (slower) than 17 km / h, or vehicle speed <P_SPD (= 17 km / h)}. If it is determined in step 15 that the traveling speed has not decreased {for example, it is 17 km / h or more (fast)}, the process proceeds to step 13 and the high speed mode is maintained (to the low speed mode). When the process ends, the process returns to the start. On the other hand, if it is determined in step 15 that the traveling speed is decreasing {for example, smaller than (slower) than 17 km / h}, the process proceeds to step 11 and the toroidal type continuously variable transmission 4. On the condition that the current gear ratio (actual gear ratio, e _CVU ) is adjusted to a value (MP) for mode switching, mode switching from the high speed mode to the low speed mode is permitted. In addition, the threshold value (for example, 17 km / h) whether the said traveling speed is falling is set similarly to the 3rd example of the above-mentioned embodiment.

  When mode switching control is performed based on the flowchart shown in FIG. 10 as described above, whether mode switching is permitted / prohibited can be determined according to the driver's operation status (intention) (for example, FIG. 10). (See the portion surrounded by the broken line X). For this reason, it is considered that hunting can be prevented by mode switching as described above. However, in addition to complicated control, as described below, there is a possibility that determination as to whether or not to permit mode switching is insufficient. That is, consider a situation where the vehicle starts in a low speed mode and accelerates at an accelerator opening of about 30%. In this case, the gear ratio of the toroidal-type continuously variable transmission is increased (shifted up) in accordance with the accelerator opening (about 30%) and the vehicle speed (for example, see the shift map shown in FIG. 5 described above). When the vehicle speed increases to a predetermined speed, the gear ratio of the toroidal continuously variable transmission reaches a mode switching point (rotation synchronization point, for example, 0.46 as the speed increasing ratio) or less. In this case, in the flowchart of FIG. 10, when the conditions of steps 4, 6, and 7 are satisfied (determined as YES) and the mode switching point (rotation synchronization point) is reached, mode switching to the high speed mode is permitted. Is done.

However, when the conditions of Steps 4, 6, and 7 are satisfied and mode switching to the high-speed mode is permitted, the driving situation at the moment when mode switching is permitted may be different as follows. It is done.
(A) When accelerating by depressing the accelerator pedal constantly.
(B) When sudden acceleration is performed in the low speed mode by depressing the accelerator pedal quickly.
(C) When the accelerator pedal is returned from a state where the accelerator pedal is fully depressed (accelerator opening is fully opened) to obtain deceleration based on the engine braking force.
In cases (a) and (c) of these, it is considered that mode switching from the low speed mode to the high speed mode should be performed, but in the case of (b), further acceleration is required. There is a possibility that mode switching to the high speed mode should not be performed. However, if the mode switching control is performed according to the flowchart of FIG. 10 described above, even in the case of (b) above, there is a possibility that the mode is switched from the low speed mode to the high speed mode as shown in FIG. . That is, there is a possibility that unnecessary mode switching may be performed during acceleration when the accelerator is depressed. In such a case, there is a possibility that quick acceleration is impaired (acceleration desired by the driver cannot be obtained), which is not preferable.

  In order to prevent such unnecessary mode switching, the “current vehicle status” is compared with the “previous vehicle status” (whether the previous accelerator pedal state is depressed / released). It is also conceivable to determine the state of (b) above by a method such as determining or detecting the stepping speed and opening speed) and responding to it (prohibiting mode switching). However, in such a case, the control is further complicated, and it may be difficult to ensure detection accuracy and reliability. As described above, since the mode switching is optimally performed when the transmission ratio of the toroidal-type continuously variable transmission 4 reaches a mode switching point (rotation synchronization point, for example, maximum deceleration state), for example, It is considered that it is difficult to give hysteresis to the switching timing according to the mode switching direction (mode switching from the low speed mode to the high speed mode, or mode switching from the high speed mode to the low speed mode).

  In view of such circumstances, the present inventor considered the mode switching control of this example as shown in FIG. In the case of this example shown in FIG. 8, as in the second example of the above-described embodiment, the controller 16 (see FIG. 12) determines whether to permit mode switching at that time. Of the toroidal-type continuously variable transmission 4 and the target speed ratio (which corresponds to the target speed ratio obtained from the speed map shown in FIG. Based on the target speed ratio of the entire step transmission). More specifically, in the case of this example, the speed ratio of the toroidal continuously variable transmission 4 that is adjusted based on the function (second function) of the controller 16 is a preset mode. When it is adjusted to a value to be switched (for example, 0.46 or less in the speed increasing ratio), the target gear ratio corresponding to the running state at that time, and the toroidal continuously variable transmission 4 at that time Whether or not mode switching is permitted depending on whether or not a predetermined condition is satisfied when the relationship with the transmission ratio (actual transmission ratio) is compared with the speed ratio of the continuously variable transmission as a whole. This is done. In other words, the target speed ratio of the entire continuously variable transmission corresponding to the running state at that time is compared with the speed ratio (actual speed ratio) of the entire continuously variable transmission at that time, and a predetermined condition is satisfied. Whether or not mode switching is permitted is determined based on whether or not the above is satisfied.

  For example, while traveling in the low speed mode, the value at which the gear ratio of the toroidal-type continuously variable transmission 4 should be switched to the preset high speed mode {for example, the maximum deceleration state (the speed increase ratio is 0.46 or less)} When the target gear ratio of the toroidal continuously variable transmission corresponding to the current running state is adjusted to the gear ratio (actual gear ratio) of the toroidal continuously variable transmission 4 at that time. On the other hand, when compared to the speed ratio of the continuously variable transmission as a whole, if it is on the deceleration side (shift down side), mode switching to the high speed mode is not permitted (maintains the low speed mode). ing. Similarly, when compared with the speed ratio of the continuously variable transmission as a whole, if it is the same or the speed increasing side (shifting up side), mode switching to the high speed mode is permitted (in high speed mode). Switch). That is, during traveling in the low speed mode, the target speed ratio of the continuously variable transmission as a whole corresponding to the (current) traveling state at that time is the speed as the entire (current) continuously variable transmission at that time. If the speed is lower than the ratio (actual speed ratio) (increase ratio, actual speed ratio> target speed ratio), the mode switching to the above high speed mode is not permitted, and the same or higher speed side ( When the speed increase ratio is the actual speed ratio ≦ the target speed ratio, the mode switching to the high speed mode is permitted.

  Further, for example, when traveling in the high speed mode, the speed ratio of the toroidal-type continuously variable transmission 4 is a value to be switched to the preset low speed mode {for example, maximum deceleration state (speed increase ratio is 0.46 or less) }, The target gear ratio of the toroidal continuously variable transmission corresponding to the running state at that time is the gear ratio (actual gear ratio) of the toroidal continuously variable transmission 4 at that time. On the other hand, when compared with the speed ratio of the continuously variable transmission as a whole, when it is on the speed increasing side (shift-up side), mode switching to the low speed mode is not permitted (maintaining the high speed mode) I have to. Also, when compared with the speed ratio of the continuously variable transmission as a whole, if the same or the speed reduction side (shift down side), the mode switching to the low speed mode is permitted (switching to the low speed mode). ). That is, during traveling in the high speed mode, the target speed ratio of the continuously variable transmission as a whole corresponding to the (current) traveling state at that time is the speed as the entire (current) continuously variable transmission at that time. If the speed is higher than the actual ratio (actual speed ratio) (increase ratio, actual speed ratio <target speed ratio), mode switching to the low speed mode is not permitted, and the same or more deceleration side ( When the speed increasing ratio is actual speed ratio ≧ target speed ratio), mode switching to the low speed mode is permitted.

  The function (first function) of the controller 16 for determining whether or not to permit mode switching as described above will be described with reference to the flowchart of FIG. The operation shown in this flowchart is also repeatedly (automatically) performed from when the ignition switch is turned on until it is turned off. Steps 1 to 3 are the same as the first to third examples of the embodiment described above and the preceding example shown in FIG. After step 3, it is determined whether or not the mode is switched as follows.

  If it is determined in step 3 that the current travel mode is the low speed mode, the process proceeds to step 4. In this step 4, the target gear ratio of the toroidal type continuously variable transmission 4 corresponding to the running state at that time (when determined to be in the low speed mode) is the toroidal type continuously variable transmission 4 at that time. When comparing with the speed ratio (actual speed ratio) corresponding to the speed ratio of the continuously variable transmission as a whole, it is determined whether or not the speed ratio is the same or increased. That is, the target speed ratio of the continuously variable transmission as a whole corresponding to the (current) traveling state at that time becomes the speed ratio (actual speed ratio) of the (current) continuously variable transmission as of that time. On the other hand, it is determined whether or not they are the same or the speed increasing side (speed increasing ratio, actual speed ratio ≦ target speed ratio). In view of the gear ratio of the toroidal-type continuously variable transmission 4, the current (current) target gear ratio obtained from the low speed mode map in the gear map of FIG. This is the same as determining whether the current gear ratio is the same as or smaller than the actual gear ratio (acceleration ratio, actual gear ratio ≧ target gear ratio).

  In such a step 4, the target speed ratio of the toroidal-type continuously variable transmission 4 is the same as the actual speed ratio or not the deceleration side (NO: the speed increasing side), that is, the continuously variable transmission as a whole. If it is determined that the target speed ratio is the same as the actual speed ratio or not on the speed increasing side (NO: on the speed reducing side) when compared with the speed ratio, the process proceeds to step 5 and the low speed mode is maintained. As it ends (without switching to the high speed mode), it returns to the start. On the other hand, in step 4 above, the target gear ratio of the toroidal-type continuously variable transmission 4 is equal to or less than the actual gear ratio (YES), that is, the speed of the continuously variable transmission as a whole. If it is determined that the target speed ratio is the same as the actual speed ratio or on the speed increasing side (YES) when the comparison is made in correspondence with the ratio, the process proceeds to step 6.

In this step 6, the current gear ratio (actual gear ratio, e _CVU ) of the toroidal-type continuously variable transmission 4 adjusted according to the target gear ratio is a preset value for mode switching {mode switching point. (MP), for example, it is determined whether or not the vehicle is adjusted to the maximum deceleration state (for example, the speed increase ratio is 0.46 or less, e _CVU ≦ 0.46)}. In step 6, it is determined that the actual transmission ratio (e _CVU ) of the toroidal-type continuously variable transmission 4 has not been adjusted to a preset value (MP) for mode switching (NO: e _CVU > MP). If YES in step S5, the flow advances to step 5 to end while maintaining the low speed mode (without switching to the high speed mode) and return to the start. On the other hand, if it is determined in step 6 above that the mode switching value (MP) has been adjusted (YES: e _CVU ≦ MP), the process proceeds to step 7 where the mode from the low speed mode to the high speed mode is reached. Allow switching (and return to start via end).

  On the other hand, if it is determined in step 3 that the current travel mode is the high speed mode, the process proceeds to step 8. In this step 8, the target gear ratio of the toroidal continuously variable transmission 4 corresponding to the running state at that time (when determined to be in the high speed mode) is determined by the toroidal continuously variable transmission 4 at that time. When the speed ratio (actual speed ratio) is compared with the speed ratio of the continuously variable transmission as a whole, it is determined whether or not the speed ratio is the same or the speed reduction side. That is, the target speed ratio of the continuously variable transmission as a whole corresponding to the (current) traveling state at that time becomes the speed ratio (actual speed ratio) of the (current) continuously variable transmission as of that time. On the other hand, it is determined whether or not they are the same or the deceleration side (acceleration ratio, actual speed ratio ≧ target speed ratio). In view of the gear ratio of the toroidal-type continuously variable transmission 4, the current target gear ratio obtained from the high-speed mode map in the gear shift map of FIG. This is the same as determining whether the current gear ratio is the same as or smaller than the actual gear ratio (acceleration ratio, actual gear ratio ≧ target gear ratio).

  In such a step 8, the target speed ratio of the toroidal-type continuously variable transmission 4 is the same as the actual speed ratio or not the deceleration side (NO: the speed increasing side), that is, the continuously variable transmission as a whole. If it is determined that the target speed ratio is the same as the actual speed ratio or not on the deceleration side (NO: on the acceleration side) when compared with the speed ratio, the process proceeds to step 9 and the high speed mode is maintained. As it ends (without switching to the low speed mode), it returns to the start. On the other hand, in step 8 above, the target gear ratio of the toroidal-type continuously variable transmission 4 is equal to or less than the actual gear ratio (YES), that is, the speed of the continuously variable transmission as a whole. If it is determined that the target speed ratio is the same as the actual speed ratio or is on the deceleration side (YES) when the comparison is made in correspondence with the ratio, the process proceeds to step 10.

In step 10, as in step 6 described above, the current speed ratio (actual speed ratio, e _CVU ) of the toroidal-type continuously variable transmission 4 adjusted according to the target speed ratio is set to a preset mode switch. It is determined whether or not it is adjusted to a value {mode switching point (MP), for example, a maximum deceleration state (for example, speed increase ratio is 0.46 or less, e _CVU ≤0.46)}. In step 6, it is determined that the actual transmission ratio (e _CVU ) of the toroidal-type continuously variable transmission 4 has not been adjusted to a preset value (MP) for mode switching (NO: e _CVU > MP). If YES in step S9, the flow advances to step 9 to end the process while maintaining the high speed mode (without switching to the low speed mode) and return to the start. On the other hand, if it is determined in step 10 that the value to be switched to the mode (MP) has been adjusted (YES: e _CVU ≦ MP), the process proceeds to step 11 to switch from the high speed mode to the low speed mode. Allow switching (and return to start via end).

In the case of this example in which the above control is performed, unnecessary mode switching can be prevented as shown in FIG. Further, such unnecessary mode switching can be prevented without requiring a complicated configuration, control, and system cost increase. In other words, it is possible to grasp the driving situation and the necessity of mode switching by simple (simple) determination, and it is possible to always switch to the optimum mode that suits the driver's intention. As a result, it is possible to realize a continuously variable transmission that is inexpensive and highly reliable, can prevent unnecessary mode switching in any vehicle situation, and can perform stable acceleration and traveling at a constant vehicle speed.
Other configurations and operations are the same as those of the first to third examples described above, and thus a duplicate description is omitted.

  In the present specification and claims, the terms “speed ratio” and “speed ratio” are used as follows. That is, 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 "). On the other hand, 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 used. The term “speed ratio” is used for the ratio between the output side and the output side. This is to make it easy to clarify whether the ratio relates to the toroidal type continuously variable transmission or the ratio related to the entire continuously variable transmission. Therefore, in the present specification and claims, both “speed ratio” and “speed ratio” are used as terms representing the ratio between the input side and the output side, and “speed ratio” The “speed ratio” does not necessarily correspond to the speed increasing ratio. For this reason, even if the term “transmission ratio” is used, the actual value of the “transmission ratio” may be expressed as a speed increase ratio (see, for example, FIGS. 5, 7, 9, and 11).

  In the above description, the present invention is combined with a toroidal continuously variable transmission and a planetary gear type transmission, and the rotation state of the output shaft is corrected with the input shaft rotated in one direction. The case where the present invention is applied to a continuously variable transmission equipped with a mode (low speed mode) capable of realizing a so-called geared neutral state that can be switched between rotation and reverse rotation has been described. However, the present invention combines a toroidal type continuously variable transmission and a planetary gear type transmission, a mode in which power is transmitted only by the toroidal type continuously variable transmission (low speed mode), and a planetary gear type which is a differential unit. The present invention can also be applied to a continuously variable transmission having a so-called power split state (high speed mode) in which main power is transmitted by a transmission and the gear ratio is adjusted by the toroidal continuously variable transmission. . The structure of the toroidal continuously variable transmission may be either a half toroidal type or a full toroidal type.

The flowchart which shows the 1st example of embodiment of this invention. The diagram for demonstrating running resistance. The diagram (map) which represented the threshold value which determines whether mode switching was performed by the relationship between running resistance and an engine speed. The flowchart which shows the 2nd example of embodiment of this invention. A diagram (shift map) showing the correlation between the target gear ratio and the vehicle speed for each accelerator opening. The flowchart which shows the 3rd example of embodiment of this invention. FIG. 6 is a diagram corresponding to part A in FIG. 5. The flowchart which shows the 4th example of embodiment of this invention. The diagram which shows the change of each state quantity at the time of depressing an accelerator and decelerating during constant speed driving | running | working in the state near the mode switching point in the case of performing the mode switching control of this example. The flowchart of the mode switching control considered before this example. FIG. 11 is a diagram similar to FIG. 9 when control is performed according to the flowchart shown in FIG. 10. The block diagram of a continuously variable transmission. The hydraulic circuit diagram 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. The diagram (map) showing the correlation with the target gear stage of a stepped transmission, a vehicle speed, and an accelerator opening. The diagram which shows another 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 Switching valve for low speed clutch 27, 27a, 27b Oil pump 28 Oil reservoir 29 Pressing pressure adjusting valve 30 Low pressure side adjusting valve 31 Manual oil pressure switching valve 32 Pressure reducing valve 33 Input side rotation sensor 34 Output side rotation sensor 35 Output shaft rotation Sensor 36 Accelerator sensor 37 Rake switch 38 Position switch 39 Engine controller

Claims (17)

  Combining a toroidal continuously variable transmission and a planetary gear type transmission via a clutch device, this clutch device is connected to realize a low speed mode that increases the reduction ratio and realizes a high speed mode that is also reduced. The low speed clutch that is disconnected when the high speed mode is realized, the high speed clutch that is connected when the high speed mode is realized and disconnected when the low speed mode is realized, and the connection / disconnection state of each of these clutches A controller for switching, and this controller is provided with a function to change the shifting state to one of the low speed mode and the high speed mode by controlling the connection and disconnection of each clutch. In a continuously variable transmission, the controller includes a first function for determining whether or not to permit mode switching between the low speed mode and the high speed mode, and at least the vehicle A target speed ratio of the toroidal continuously variable transmission corresponding to the target speed ratio of the continuously variable transmission is obtained based on the current traveling state of the vehicle obtained from the travel speed and the accelerator opening, and this A second function for adjusting the gear ratio of the toroidal-type continuously variable transmission to the target gear ratio, and whether to permit mode switching based on the first function is determined at that time A continuously variable transmission characterized in that it is performed on the basis of the transmission ratio of the toroidal type continuously variable transmission and the running resistance applied to the vehicle.   Even if the gear ratio of the toroidal-type continuously variable transmission is adjusted to a preset value for mode switching based on the second function, if the current running resistance does not satisfy the predetermined condition, the mode switching is performed. The continuously variable transmission according to claim 1, which is not permitted.   The mode switching from the low speed mode to the high speed mode is permitted under the condition that the gear ratio of the toroidal type continuously variable transmission is adjusted to a value to be set in advance, and from the high speed mode to the low speed mode. The mode switching is not permitted even if the gear ratio of the toroidal-type continuously variable transmission is adjusted to a preset value for mode switching unless the running resistance at that time satisfies a predetermined condition. The continuously variable transmission described in any one of 1-2.   The actual driving that is estimated to be necessary to realize this running state, which is obtained from the net driving force output from the engine at that time and the state quantity that represents the running state of the vehicle at that time. The continuously variable transmission according to any one of claims 1 to 3, wherein the continuously variable transmission is obtained from a difference from the force.   Combining a toroidal continuously variable transmission and a planetary gear type transmission via a clutch device, this clutch device is connected to realize a low speed mode that increases the reduction ratio and realizes a high speed mode that is also reduced. The low speed clutch that is disconnected when the high speed mode is realized, the high speed clutch that is connected when the high speed mode is realized and disconnected when the low speed mode is realized, and the connection / disconnection state of each of these clutches A controller for switching, and this controller is provided with a function to change the shifting state to one of the low speed mode and the high speed mode by controlling the connection and disconnection of each clutch. In a continuously variable transmission, the controller includes a first function for determining whether or not to permit mode switching between the low speed mode and the high speed mode, and at least the vehicle A target speed ratio of the toroidal continuously variable transmission corresponding to the target speed ratio of the continuously variable transmission is obtained based on the current traveling state of the vehicle obtained from the travel speed and the accelerator opening, and this A second function for adjusting the gear ratio of the toroidal-type continuously variable transmission to the target gear ratio, and whether to permit mode switching based on the first function is determined at that time A continuously variable transmission characterized in that it is performed on the basis of the gear ratio of the toroidal type continuously variable transmission and the target gear ratio determined by the second function.   Based on the second function, even if the gear ratio of the toroidal-type continuously variable transmission is adjusted to a preset value for mode switching, it is assumed that this mode switching has been performed at that time. The continuously variable transmission according to claim 5, wherein mode switching is not permitted unless the target gear ratio corresponding to the running state reaches a predetermined value.   The mode switching from the low speed mode to the high speed mode is permitted under the condition that the gear ratio of the toroidal type continuously variable transmission is adjusted to a value to be set in advance, and from the high speed mode to the low speed mode. The mode switching is performed when it is assumed that the mode switching to the low speed mode has been performed even if the gear ratio of the toroidal continuously variable transmission is adjusted to a preset value for mode switching. The continuously variable transmission according to any one of claims 5 to 6, wherein the transmission is not permitted unless the target gear ratio corresponding to the running state at the time reaches a predetermined value.   The target gear ratio of the toroidal-type continuously variable transmission is the speed of the continuously variable transmission required to obtain at least the vehicle speed, the accelerator opening, and the optimum deceleration force or driving force, which is stored in advance in the controller. The low speed mode shift map used in the low speed mode to which the low speed clutch is connected and the high speed clutch are obtained based on the shift map representing the correlation with the target speed ratio corresponding to the ratio. The continuously variable transmission according to any one of claims 5 to 7, wherein the continuously variable transmission is configured by a high-speed mode shift map used in a high-speed mode to which the is connected.   The speed ratio of the toroidal continuously variable transmission is adjusted by the second function using the shift map corresponding to the mode at that time out of the shift maps for the low speed mode and the high speed mode. Even if the gear ratio is adjusted to a preset value for mode switching, it is assumed that this mode switching has been performed, and at that time point obtained using the mode shift map to be adopted after mode switching. The continuously variable transmission according to claim 8, wherein mode switching is not permitted unless the target gear ratio corresponding to the running state reaches a predetermined value.   In the state of the high speed mode in which the speed ratio of the toroidal type continuously variable transmission is adjusted by the second function using the high speed mode speed change map, the mode should be switched to the low speed mode in which this speed ratio is preset. The mode switching to the low-speed mode is not permitted unless the target gear ratio corresponding to the driving state at that time obtained from the low-speed mode shift map becomes a predetermined value even if the value is adjusted. The continuously variable transmission described in any one of 8-9.   Based on the second function, when the gear ratio of the toroidal continuously variable transmission is adjusted to a preset value for mode switching, the toroidal continuously variable transmission corresponding to the running state at that time Whether the relationship between the target gear ratio of the machine and the gear ratio of the toroidal type continuously variable transmission at that time satisfies a predetermined condition when compared with the speed ratio of the entire continuously variable transmission 6. The continuously variable transmission according to claim 5, wherein it is determined whether or not mode switching is permitted depending on whether or not.   While traveling in the low speed mode, the target transmission ratio of the toroidal continuously variable transmission corresponding to the traveling state at that time is compared with the transmission ratio of the toroidal continuously variable transmission at that time as the entire continuously variable transmission. The continuously variable transmission according to claim 11, wherein the mode switching to the high speed mode is not permitted when the speed reduction is compared when the speed ratio is compared with each other.   While traveling in the low speed mode, the target transmission ratio of the toroidal continuously variable transmission corresponding to the traveling state at that time is compared with the transmission ratio of the toroidal continuously variable transmission at that time as the entire continuously variable transmission. The continuously variable transmission according to any one of claims 11 to 12, wherein mode switching to the high speed mode is permitted when the speed ratio is the same or the speed increasing side when compared in accordance with the speed ratio. apparatus.   While traveling in the high-speed mode, the target transmission ratio of the toroidal continuously variable transmission corresponding to the current traveling state is compared with the transmission ratio of the toroidal continuously variable transmission at that time as the entire continuously variable transmission. The continuously variable transmission according to claim 11, wherein the mode switching to the low speed mode is not permitted when the speed is increased when compared in accordance with the speed ratio.   While traveling in the high-speed mode, the target transmission ratio of the toroidal continuously variable transmission corresponding to the current traveling state is compared with the transmission ratio of the toroidal continuously variable transmission at that time as the entire continuously variable transmission. 15. The continuously variable transmission according to claim 11, wherein mode switching to the low speed mode is permitted if the speed ratio is the same or the speed reduction side when compared in accordance with the speed ratio.   Combining a toroidal continuously variable transmission and a planetary gear type transmission via a clutch device, this clutch device is connected to realize a low speed mode that increases the reduction ratio and realizes a high speed mode that is also reduced. The low speed clutch that is disconnected when the high speed mode is realized, the high speed clutch that is connected when the high speed mode is realized and disconnected when the low speed mode is realized, and the connection / disconnection state of each of these clutches A controller for switching, and this controller is provided with a function to change the shifting state to one of the low speed mode and the high speed mode by controlling the connection and disconnection of each clutch. In a continuously variable transmission, the controller includes a first function for determining whether or not to permit mode switching between the low speed mode and the high speed mode, and at least the vehicle A target speed ratio of the toroidal continuously variable transmission corresponding to the target speed ratio of the continuously variable transmission is obtained based on the current traveling state of the vehicle obtained from the travel speed and the accelerator opening, and this And a second function for adjusting the gear ratio of the toroidal type continuously variable transmission to this target gear ratio, and whether or not to allow mode switching as the first function is determined at that time Based on the gear ratio of the toroidal-type continuously variable transmission, the accelerator opening, the operating condition of the braking device, and the traveling speed of the vehicle, the mode switching from the high speed mode to the low speed mode is performed. Based on the second function, even if the gear ratio of the toroidal-type continuously variable transmission is adjusted to a preset value for mode switching, the accelerator opening is 0% and the braking device operates. If not If the running speed of the vehicle does not become a predetermined value, the continuously variable transmission, characterized in that not allowed.   The continuously variable transmission according to any one of claims 1 to 16, comprising a mode capable of realizing a geared neutral state in which the output shaft is stopped while the input shaft is rotated in one direction.

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