JP2007309383A - Continuously variable transmission device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prohibit a mode change from a low speed mode to a high speed mode when the mode change is not desired by a driver. <P>SOLUTION: The determination of whether permitting or not the mode change from the low speed mode to the high speed mode is made as follows: the mode change is not permitted when an accelerator opening is 0% and a braking device is operated even if the speed ratio of a toroidal type continuously variable transmission which is controlled depending on a target speed ratio corresponding to a travelling state at this time is controlled to be at a preset mode change point. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an improvement of a continuously variable transmission incorporating a toroidal continuously variable transmission, for example, used as an automatic transmission for a vehicle (automobile), and does not require mode switching from a low speed mode to a high speed mode (driver) To achieve a structure that can be prevented from being done).

  The use of a toroidal-type continuously variable transmission as an automatic transmission for automobiles is described in many publications such as Patent Documents 1 and 2, Non-Patent Documents 1 and 2, and is partly implemented and well known. It is. 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.

  FIGS. 4-5 has shown the continuously variable transmission provided with the mode which can implement | achieve the geared neutral state described in patent documents 5-6. 4 shows a block diagram of the continuously variable transmission, and FIG. 5 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. 5), 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. 5). 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. 5) 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. 5) 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. 5). 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. 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. 6 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. The target speed ratio of the toroidal type continuously variable transmission corresponding to the target speed ratio is shown in FIG. 2 of the first example of the embodiment of the present invention described later, for example, stored in advance in the controller 16. Such a shift map (correlation between the target gear ratio for each accelerator opening and the vehicle speed) can be obtained.

  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. In other words, this mode switching can be realized in both the low-speed mode and the high-speed mode, with the speed ratio of the continuously variable transmission adjusted according to the current running state (corresponding to the target speed ratio). 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. 6 (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 7 that has been disconnected until then is connected, and the low-speed clutch 8 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 8 that has been disconnected until then is connected, and the high-speed clutch 7 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, when the mode switching from the low speed mode to the high speed mode is performed only on condition that the gear ratio of the toroidal type continuously variable transmission 4 reaches the mode switching point (for example, the speed increasing ratio is 0.4), Depending on the driving condition, the mode switching may be performed without the driver's desire. That is, for example, when traveling on a downward slope (downhill in the traveling direction), the accelerator pedal is released from the downward slope (while the accelerator opening is 0%), and the vehicle is moving forward in the low speed mode (see FIG. Consider the case where the vehicle is traveling between point GN and point a). In such a case, depending on the slope of the road surface (when the slope is steep), the vehicle traveling speed (vehicle speed) may increase (accelerate) without the accelerator pedal being depressed. When the vehicle speed increases, the target gear ratio of the toroidal continuously variable transmission 4 changes to the deceleration side (point i side in FIG. 6) in order to change the speed ratio of the continuously variable transmission to the acceleration side. Then, based on the change in the target gear ratio, the (actual) gear ratio of the toroidal continuously variable transmission 4 is decelerated, and when this gear ratio reaches the mode switching point (a point in FIG. 6), the low speed mode To high speed mode.

  When the low-speed mode is switched to the high-speed mode in this way, the vehicle speed increases and the engine braking force decreases further (the vehicle is further accelerated and the engine braking force is further decreased). In such a case, there is no problem if the driver accepts (intentions) the increase (acceleration) of the vehicle speed. However, when the driver does not want to accelerate or wants to keep the vehicle speed substantially constant, it is not preferable to perform the mode switching from the low speed mode to the high speed mode as described above. In particular, when the driver depresses the brake pedal (even a little) (intended to decelerate or drive at a constant speed), the mode switching (low speed mode → high speed mode) accompanying the increase in vehicle speed as described above is performed. If the vehicle speed tends to further increase (when the engine braking force further decreases), further depression of the brake pedal is required. In other words, mode switching from the low-speed mode to the high-speed mode as described above is not preferable because it may hinder stable constant-speed traveling or deceleration traveling.

  In order to prevent such inconvenience, for example, the correlation (shift map) between the vehicle speed and the target gear ratio of the toroidal type continuously variable transmission corresponding to this vehicle speed when the accelerator opening degree related to the low speed mode is 0%. It is possible to set as follows. That is, the target speed ratio is less likely to reach the mode switching point with respect to the increase in the vehicle speed. More specifically, the amount of change (inclination) of the target speed ratio with respect to the vehicle speed is moderated to correspond to the mode switching point. It is possible to increase the vehicle speed. However, in such a case, for example, when the accelerator pedal is depressed to accelerate (when the accelerator opening is not 0%), the mode switching timing from the low speed mode to the high speed mode is delayed, and this low speed mode is maintained. This may have an unfavorable effect, such as an excessively wide range. In addition, when the accelerator opening is 0%, it may be possible to adjust (control) the gear ratio using another correlation (speed map) to obtain the required engine braking force, but the control is complicated. This is not preferable.

  Patent Documents 7 and 8 describe a technique for preventing frequent mode switching between the low speed mode and the high speed mode. However, in each of these Patent Documents 7 and 8, there is a technique for preventing the inconvenience as described above, that is, for example, mode switching from the low speed mode to the high speed mode when the driver does not want on a downhill is prevented. The technology is not described. Patent Document 9 discloses a technique for preventing repeated shifting (shifting up and down) in a stepped transmission having a stepped transmission mechanism (the gear ratio during travel cannot be adjusted steplessly). Is described. Patent Document 10 describes a technique for shifting down from the current gear position in order to increase the engine braking force when a brake pedal is depressed in a vehicle incorporating a stepped transmission. Yes. However, the technology of the stepped transmission described in these Patent Documents 9 and 10 cannot be used as it is for the mode switching of the continuously variable transmission, and as described above, the low speed mode is not desired by the driver. Therefore, it is not possible to prevent the mode from being switched to the high speed mode.

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 JP-A-5-340467 Motoo Aoyama, “Bessed Best Car Red Badge Series 245 / A book that understands the latest mechanics of cars”, Sangensha Co., Ltd./Kodansha Co., Ltd., December 20, 2001, p. 92-93 Hirohisa Tanaka, “Toroidal CVT”, Corona Inc., July 13, 2000

  In view of the circumstances as described above, the present invention was invented to realize a structure capable of preventing the mode switching from the low speed mode to the high speed mode from being performed unnecessarily (though not desired by the driver). is there.

The continuously variable transmission 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 according to the present invention, the controller has a first function for determining whether or not to permit mode switching between the low speed mode and the high speed mode. Along with this, the toroidal continuously variable transmission corresponding to the target speed ratio of the continuously variable transmission based on at least the vehicle traveling speed and the accelerator opening, and the vehicle traveling state at that time. And a second function for adjusting the speed ratio of the toroidal continuously variable transmission to the target speed ratio.
The determination as to whether or not to permit mode switching from the low speed mode to the high speed mode, which is the first function, is performed based on the gear ratio of the toroidal continuously variable transmission based on the second function. The accelerator opening is 0% (the accelerator pedal is not depressed) even if the value is adjusted to the value to be switched to the mode {for example, the maximum deceleration state (for example, the speed increase ratio is 0.46 or less)} In addition, when the braking device is operating (the service brake is operating or the brake pedal is depressed), the mode switching is not permitted.

Further, when the continuously variable transmission as described above is implemented, for example, as described in claim 2, as long as the accelerator opening is 0% and the braking device is operating, Do not allow mode switching.
Alternatively, as described in claim 3, even when the accelerator opening is 0% and the braking device is operating, the mode switching is permitted only when a predetermined condition is satisfied. .
In this case, for example, as described in claim 4, the vehicle traveling speed (corresponding to the rotational speed of the output-side disk or the rotational speed of the output shaft of the continuously variable transmission) becomes a predetermined value ( For example, when the threshold value is larger than a preset threshold value or exceeds this threshold value), the mode switching is permitted. Alternatively, as described in claim 5, the rotational speed of the drive source (engine) (corresponding to the rotational speed of the input disk or the rotational speed of the input shaft of the continuously variable transmission) becomes a predetermined value. In the case of (for example, greater than or equal to a preset threshold value), the mode switching is permitted. Further, preferably, when the continuously variable transmission described in claims 4 and 5 is implemented, the predetermined value is not changed from the low speed mode to the high speed mode as described in claim 6. Also, the state quantity (for example, rotation speed) of the drive source is set within a range of values that do not exceed allowable values (maximum allowable rotation speed, overrun speed, overrev speed).

  When the above-described continuously variable transmission is implemented, the target speed ratio of the continuously variable transmission, which is obtained based on the running state at that time in a state where mode switching to the high speed mode is not permitted, There is a possibility that the value cannot be realized in the current low 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 low speed mode, the speed ratio of the toroidal continuously variable transmission is adjusted to a target speed ratio corresponding to the target speed ratio (in the current low speed mode). The shift control is performed according to the running state at that time.) On the other hand, if mode switching to the high speed mode is permitted, the high speed clutch is connected and the low speed clutch is disconnected to switch to the high speed mode. Then, in the state of switching to the high speed mode in this way, the target speed ratio (target speed ratio) according to the driving state at that time is adjusted (in the high speed mode, the shift control according to the driving state at that time is performed. Do).

According to the continuously variable transmission of the present invention as described above, a structure that can prevent the mode switching from the low speed mode to the high speed mode (unless the driver desires it) has a complicated structure or It can be realized at low cost while ensuring reliability without requiring control.
That is, whether or not to allow mode switching from the low speed mode to the high speed mode is determined not only by the gear ratio (actual gear ratio) of the toroidal-type continuously variable transmission at that time, but also the gear ratio and the time point The operation is performed based on the accelerator opening and the operation of the braking device. From the accelerator opening and the operation of the braking device, the driver's intention can be estimated. 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 mode switching is performed according to the estimated intention of the driver at that time. By determining whether or not to permit, it is possible to prevent unnecessary mode switching from the low speed mode to the high speed mode (although the driver does not want it). As a result, for example, when traveling on a downhill or the like in a low speed mode, if the brake pedal is depressed (even a little), the mode switching is not performed, and the necessary engine braking force can be stably obtained. It is possible to prevent the vehicle speed from increasing even though the driver does not want it. 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.

  In a state in which mode switching from the low speed mode to the high speed mode is not permitted, a value (for example, an increase in speed) at which the gear ratio of the toroidal continuously variable transmission is set in advance with the low speed clutch connected. The ratio is maintained at 0.46 or less). In such a state, depending on, for example, the degree of road inclination and the vehicle weight (loading weight, number of passengers, etc.), a large force (a force against the engine braking force) that tries to rotate the engine from the wheels to the engine. ) May be added. That is, when the slope of the road surface is steep and the vehicle weight is large, if the transmission ratio of the toroidal type continuously variable transmission is maintained at the value for mode switching as described above, the engine The rotational speed can increase significantly. On the other hand, as described in claims 3 to 6, if the vehicle traveling speed or the engine rotational speed reaches a predetermined value, the mode switching from the low speed mode to the high speed mode is permitted. This prevents excessive load on the engine. For this reason, even when the road surface is steep and the vehicle weight is large as described above, it is possible to prevent the state quantity of the engine from exceeding an allowable value and to ensure the life of the engine. In addition, even when mode switching from the low speed mode to the high speed mode is permitted as described above, the driver can drive according to the intention of the driver by appropriately increasing the amount of depression of the brake pedal ( The vehicle can be decelerated).

  Further, when a structure having 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 as described in claim 7, the low speed mode and the high speed mode are employed. Mode switching between and is performed at low speed. Therefore, every time the vehicle is started and stopped, the transmission ratio of the toroidal type continuously variable transmission easily reaches the mode switching point, and the necessity of preventing the mode switching from being performed unnecessarily increases. The effect can be obtained more remarkably.

[First example of embodiment]
1 and 2 show a first example of an embodiment of the present invention corresponding to claims 1, 2, and 7. FIG. The feature of this example is to determine whether or not to permit this mode switching in order to prevent the mode switching from the low speed mode to the high speed mode (unless the driver wants it). It is in the point which devised how. Since the structure and operation of the other parts are the same as those of the conventional structure shown in FIGS. 4 to 5 described above, the overlapping description will be omitted or simplified, and the following description will focus on the characteristic parts of this example. In 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 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.

  In the case of this example, similarly to the conventional structure shown in FIGS. 4 to 5, 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 connection / disconnection state of the low-speed and high-speed clutches 7 and 8 can be freely switched 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 by the sensors 33, 34, and 35, the gear ratio of the toroidal 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 representing the running state) and the target speed ratio (target speed ratio) is previously mapped in the memory of the controller 16 (the speed change as shown in FIG. 2 described later). Map) and calculation formulas. Then, using such a map (MAP) and a calculation formula, 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 target gear ratio of the toroidal-type continuously variable transmission 4 is obtained based on a shift map as shown in FIG. This shift map (Shift MAP) is the target speed ratio (vertical axis) corresponding to the vehicle speed (horizontal axis) and the speed ratio of the continuously variable transmission required to obtain the optimum deceleration force or driving force. Is shown for each accelerator opening. Also, 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. 2) sandwiches the mode switching point. Similarly, the high-speed side (the right side in FIG. 2) corresponds to the “high-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 is disconnected, the low-speed mode shift map is used at that time. The target gear ratio corresponding to the accelerator opening and the traveling speed of the vehicle is obtained, and the gear ratio of the toroidal type 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, the controller 16 is allowed to change the mode between the low speed mode and the high speed mode in addition to the speed ratio control function (second function) performed using the above-described shift map. A function for determining whether or not to perform the function (the first function described in the claims). That is, during traveling in the low speed mode, the speed ratio of the toroidal continuously variable transmission 4 that is adjusted according to the traveling state (target speed ratio) of the vehicle at that time should be switched to a preset mode. When the value is adjusted (decelerated) to a value {for example, maximum deceleration state (speed increase ratio: 0.46 or less)}, it is determined whether or not mode switching from the low speed mode to the high speed mode is permitted. Specifically, the accelerator opening is 0% (depressing the accelerator pedal is released) and the braking device is operating (the service brake is operating, the brake pedal is being pressed). In this case, mode switching from the low speed mode to the high speed mode is not permitted as long as the accelerator opening is 0% and the braking device is operating.

  In this way, the target speed ratio of the continuously variable transmission, which is obtained based on the running state at that time in a state where mode switching from the low speed mode to the high speed mode is not permitted, is a value that cannot be realized in the current low speed mode. There is a possibility. In such a case, regardless of the target speed ratio, the speed ratio of the toroidal-type continuously variable transmission 4 is set to a value at which the preset mode switching should be performed (for example, the speed increase ratio is 0.46 or less). Keep it. If the target speed ratio is a value that can be realized in the current low 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 low speed mode). The shift control according to the running state at that time is performed). On the other hand, if mode switching to the high speed mode is permitted, the high speed clutch 8 is connected and the low speed clutch 7 is disconnected to switch to the high speed mode. Then, in the state of switching to the high speed mode in this way, the target speed ratio (target speed ratio) according to the driving state at that time is adjusted (in the high speed mode, the shift control according to the driving state at that time is performed. Do).

The function (first function) for determining whether or not to permit mode switching from the low speed mode to the high speed mode 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 mode switching is not performed in the low speed mode, the process ends as it is 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 ends as it is (because the low speed mode is not switched to the high speed mode), Return to 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 which mode switching should be performed (e _CVU ≦ MP) is determined, the _routine proceeds to step 5 where the accelerator opening is 0% (ACCEL = 0). %) (Depressing the accelerator pedal is released). This determination is made based on the detection signal of the accelerator sensor 36, for example. If it is determined in step 5 that the accelerator opening is not 0% (the accelerator pedal is depressed, for example, ACCEL ≧ 1%), mode switching from the low speed mode to the high speed mode is permitted. That is, the process proceeds to step 6 where the high-speed clutch 8 is connected and the low-speed clutch 7 is disconnected by switching the shift solenoid valve 20.

  On the other hand, if it is determined in step 5 that the accelerator opening is 0% (ACCEL = 0%), the process proceeds to step 7 where the braking device is operating (the service brake is operating, Determine whether the brake pedal is depressed, BRAKE = ON. This determination is made based on, for example, a detection signal from the brake switch 37. If it is determined in step 7 that the braking device is not operating (BRAKE = OFF), mode switching from the low speed mode to the high speed mode is permitted. That is, the process proceeds to step 6 where the high-speed clutch 8 is connected and the low-speed clutch 7 is disconnected by switching the shift solenoid valve 20. On the other hand, if it is determined in step 7 that the braking device is operating (BRAKE = ON), the mode is terminated and returned to the start without permitting mode switching from the low speed mode to the high speed mode. That is, as long as it is determined in steps 5 and 7 as described above that the accelerator opening is 0% and the braking device is operating, mode switching from the low speed mode to the high speed mode is not permitted (mode switching). Do not do).

According to the continuously variable transmission of this example as described above, a structure that can prevent unnecessary mode switching from the low-speed mode to the high-speed mode (though not desired by the driver) Without requiring control, it can be provided at a low price while ensuring reliability.
That is, whether or not to allow mode switching from the low speed mode to the high speed mode is determined not only by the gear ratio (actual gear ratio) of the toroidal-type continuously variable transmission 4 at that time, This is based on the accelerator opening at the time and the operation of the braking device. From the accelerator opening and the operation of the braking device, the driver's intention can be estimated. For this reason, even when the transmission ratio of the toroidal type continuously variable transmission 4 adjusted according to the target transmission ratio reaches the mode switching point, the mode switching is performed according to the estimated intention of the driver at that time. By determining whether or not to permit the operation, it is possible to prevent unnecessary mode switching from the low speed mode to the high speed mode (although the driver does not want it). As a result, for example, when traveling downhill or the like in the low speed mode, if the brake pedal is depressed (even a little), the mode switching is not performed and the necessary engine braking force can be stably obtained. This can prevent the vehicle speed from increasing, which the driver does not want.

  In order to prevent the decrease in engine braking force and the acceleration of the vehicle that are not desired by the driver by switching from the low speed mode to the high speed mode on a downhill or the like, as described above (in the paragraph [0014] part) As described above, it is conceivable to set the correlation (shift map) between the vehicle speed and the target gear ratio corresponding to the vehicle speed when the accelerator opening degree related to the low speed mode is 0% as follows. That is, the target speed change ratio is made difficult to reach the mode switching point with respect to the increase in the vehicle speed. More specifically, as shown in FIG. 7, the vehicle speed and the target speed change ratio when the accelerator opening is 0%. The amount of change (slope) in the target gear ratio with respect to the vehicle speed is moderated by changing the correlation of the vehicle from the solid line state to the broken line state (widening the use range of the low speed mode and switching the mode at a higher speed). Thus, it is conceivable to increase the vehicle speed corresponding to the mode switching point.

  However, in such a case, as described above, when the accelerator pedal is depressed to accelerate (when the accelerator opening is not 0%), the mode switching timing from the low speed mode to the high speed mode is delayed, etc. May have an adverse effect. Specifically, the frequency of using the low speed mode in which the torque passing through the toroidal continuously variable transmission increases is increased, which is disadvantageous in terms of ensuring the durability of the toroidal continuously variable transmission. In addition, as described above, when the accelerator opening is 0%, the gear ratio may be adjusted (controlled) using another correlation (speed map) to obtain the required engine braking force. The control may be complicated, which is not preferable. On the other hand, as in this example, whether or not to permit mode switching from the low speed mode to the high speed mode is determined based on the speed ratio (actual speed ratio) of the toroidal-type continuously variable transmission 4 at that time, If it is performed based on the accelerator opening at that time and the operation of the braking device at that time, the structure that can prevent the inconveniences described above can be achieved without requiring complicated configuration and control. It can be realized at low cost while ensuring.

  In the case of this example, whether or not to perform this mode switching is determined not only in the mode switching from the low speed mode to the high speed mode as described above but also in the mode switching from the high speed mode to the low speed mode. It is configured like this. By adopting such a configuration, even when the gear ratio of the toroidal type continuously variable transmission 4 is operated near the mode switching point, the mode switching is not repeated frequently. That is, in the case of this example, the controller 16 is provided with a function for determining whether or not to permit mode switching from the high speed mode to the low speed mode, and this determination is performed based on the above-described toroidal type. The gear ratio of the step transmission 4 and the running resistance applied to the vehicle at that time (the sum of the forces that impede the running such as rolling resistance, air resistance, gradient resistance, acceleration resistance, braking resistance, etc.), or In addition, it is configured so as to be performed based on the target gear ratio obtained in accordance with the running state at that time.

  More specifically, during traveling in the high speed mode, the transmission ratio of the toroidal continuously variable transmission 4 that is adjusted according to the current traveling state (corresponding target transmission ratio) is set in advance. Even if it is adjusted to a value to be switched to the mode {for example, maximum deceleration state (speed increase ratio: 0.46 or less)}, if the running resistance at that time does not satisfy a predetermined condition (for example, more than a preset threshold value) The mode switching is not permitted unless it is large or exceeds this threshold. Alternatively, even if the gear ratio of the toroidal-type continuously variable transmission 4 is adjusted to a preset value for mode switching, it is assumed that the mode switching to the low speed mode has been performed at that time. If the target gear ratio corresponding to the traveling state of the vehicle does not become a predetermined value {for example, a value on the higher speed side than the mode switching point (MP), for example, unless the speed ratio is greater than 0.58}, the mode Switching is not allowed.

The function of determining whether or not to permit mode switching from the high speed mode to the low speed mode provided in the controller 16 will be described with reference to the flowchart of FIG. 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 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 8, 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 8 that the mode switching value (MP) has been adjusted (e _CVU ≦ MP), the process proceeds to the subsequent step 9 where the running resistance at that time is a predetermined value. It is determined whether or not the condition is satisfied. This running resistance realizes this running state obtained from, for example, 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). Then, it is determined whether or not the running resistance is larger than, for example, a threshold value (P_PWR) corresponding to the engine speed at that time (running resistance> P_PWR). Alternatively, in step 9, the determination based on whether or not the target gear ratio at that time satisfies a predetermined condition can be made instead of the determination based on such running resistance. More specifically, for example, the target gear ratio corresponding to the traveling state at that time obtained from the shift map (low speed mode shift map) to be adopted after the mode switching is a predetermined value (for example, 0. 58) (target gear ratio> 0.58).

  When it is determined in step 9 that the running resistance is equal to or less than a threshold value (running resistance ≦ P_PWR), or the target speed ratio is equal to or less than a predetermined value (target speed ratio ≦ 0.58). Does not allow mode switching from the high speed mode to the low speed mode, and ends and returns to the start. On the other hand, when it is determined that the running resistance is larger than the threshold (running resistance> P_PWR) or the target speed ratio is larger than a predetermined value (target speed ratio> 0.58), Allows mode switching from high speed mode to low speed mode. That is, the process proceeds to step 10 where the low-speed clutch 7 is connected and the high-speed clutch 8 is disconnected by switching the shift solenoid valve 20.

  If the mode switching from the high speed mode to the low speed mode is not permitted in step 9 above, the target speed ratio of the continuously variable transmission determined based on the running state at that time is the current high speed mode. The value may not be realizable. 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 preset value for switching the mode {for example, the maximum deceleration state (the speed increase ratio is 0). .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 target speed ratio (target speed ratio) is adjusted according to the driving state at that time (shift control according to the driving state at that time is performed in the low speed mode). .

  In the case of this example as described above, whether or not to allow mode switching from the high speed mode to the low speed mode is determined only by the gear ratio (actual gear ratio) of the toroidal continuously variable transmission 4 at that time. Rather, it is based on the gear ratio, the running resistance obtained from the state quantity representing the running state at that time, or the target gear ratio at that time. Among these, from the running resistance, it is possible to estimate the running state at that time, that is, how much the vehicle is decelerating or accelerating (accelerating), or running at a constant speed. Further, the traveling tendency of the vehicle can be estimated from the target gear ratio. Then, depending on whether or not such running resistance or target gear ratio exceeds a preset threshold value or a predetermined value, the current running state returns to the original driving mode again immediately after the mode is switched, etc. It is possible to determine whether or not there is a high possibility that unnecessary mode switching is repeated. For this reason, even when the gear ratio of the toroidal type continuously variable transmission 4 has reached the mode switching point, it is determined whether or not the mode switching is permitted based on the running resistance or the target gear ratio as described above. Therefore, it is possible to prevent unnecessary mode switching from being repeated.

[Second Example of Embodiment]
FIGS. 3-4 has shown the 2nd example of embodiment of this invention corresponding to Claim 1, 3-7. In the case of the first example described above, whether or not to permit mode switching from the low speed mode to the high speed mode is determined when the accelerator opening is 0% and the braking device is operating. As long as the accelerator opening is 0% and the braking device is operating, mode switching is not always permitted. On the other hand, in the case of this example, mode switching is permitted only when a predetermined condition is satisfied even when the accelerator opening is 0% and the braking device is operating. . Specifically, even when the accelerator opening is 0% and the braking device is operating, the rotation of the input side disk 10 corresponding to the rotational speed {of the engine 1 (see FIG. 4) as the drive source. Only when the speed or the rotational speed of the input shaft 3 (see FIG. 4) of the continuously variable transmission becomes a predetermined value, for example, it is larger than a preset threshold value (P_ENG_ID) (rotational speed> P_ENG_ID). Only in the case of being allowed, it is allowed.

Instead of the rotational speed of the engine 1, the traveling speed of the vehicle {the rotational speed of the output side disk 11 or the rotational speed of the output shaft 9 of the continuously variable transmission (see FIG. 4)} is a predetermined value. Only when the value becomes a value, for example, it is possible to permit only when the value is larger than a preset threshold value (P_SPD_OD) (travel speed> P_SPD_OD). In any case, the predetermined values (P_ENG_ID, P_SPD_OD) can be set such that the state quantity (for example, the rotational speed) of the engine 1 is an allowable value (maximum allowable rotational speed, Within the range of values that do not exceed (overrun speed, overrev speed), an optimal value obtained in advance by calculation, experiment, simulation, or the like is set. Moreover, it can also be set as the tuning value which changes the value according to the driving | running | working state (vehicle condition) at the time. In any case, before the state quantity of the engine 1 exceeds the allowable value, even when the accelerator opening is 0% and the braking device is operating, the mode switching from the low speed mode to the high speed mode is performed. Do it. The predetermined value is, for example, 5000 min ⁻¹ (rpm) for the rotational speed (P_ENG_ID) of the engine 1 and 30 km / h for the traveling speed (P_SPD_OD), for example.

The determination operation of whether or not to permit mode switching from the low speed mode to the high speed mode, which is a feature of this example, will be described with reference to the flowchart of FIG. In the flowchart of FIG. 3, the same number of steps as those in FIG. 1 are given to the steps for performing the same operations as those in the flowchart of FIG. For this reason, the description of the portions with the same number of steps is omitted, and the operation (mainly step 11) which is the feature of this example will be described below.
In step 3, the current travel mode is determined to be the low speed mode, and in step 4, the current gear ratio (actual gear ratio, e _CVU ) of the toroidal continuously variable transmission 4 adjusted according to the target gear 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 process proceeds to step 5. Then, if it is determined in step 5 that the accelerator opening is 0% (ACCEL = 0%), and it is determined in subsequent step 7 that the braking device is operating (BRAKE = ON), Proceed to step 11.

  In this step 11, it is determined whether or not the rotational speed or traveling speed of the engine 1 is larger than a preset threshold value (P_ENG_ID, P_SPD_OD) (rotational speed> P_ENG_ID, traveling speed> P_SPD_OD). If it is determined in step 11 that the rotational speed or traveling speed of the engine 1 is equal to or lower than the threshold value (rotational speed ≦ P_ENG_ID, traveling speed ≦ P_SPD_OD), the state quantity of the engine 1 exceeds the allowable value. It can be estimated that this is not the case (the engine 1 is unlikely to be overloaded, even if the speed ratio of the toroidal-type continuously variable transmission 4 remains at the mode switching point). For this reason, the process ends and returns to the start without permitting mode switching from the low speed mode to the high speed mode.

  On the other hand, if it is determined in step 11 that the rotational speed or traveling speed of the engine 1 has exceeded the threshold value (rotational speed> P_ENG_ID, traveling speed> P_SPD_OD), the state quantity of the engine 1 has an allowable value. Proceed to step 6 because it can be estimated that the engine 1 is likely to be exceeded (if the speed ratio of the toroidal-type continuously variable transmission remains at the mode switching point, an excessive load is likely to be applied to the engine 1). . That is, by permitting mode switching from the low speed mode to the high speed mode and switching the shift solenoid valve 20, the high speed clutch 8 and the low speed clutch 7 (see FIG. 5) are disconnected. By switching to the high speed mode in this way, it is possible to prevent an excessive load from being applied to the engine 1.

In the case of this example as described above, for example, since the road surface is steep and the vehicle weight (loading weight, number of passengers, etc.) is large, an attempt is made to rotate the engine 1 from the wheels to the engine 1. Even if a large force (force against engine braking force) is applied, the state quantity of the engine 1 is prevented from exceeding an allowable value, and the life of the engine 1 can be ensured. In addition, even when mode switching from the low speed mode to the high speed mode is permitted as described above, the driver can drive according to the intention of the driver by appropriately increasing the amount of depression of the brake pedal ( The vehicle can be decelerated).
Other configurations and operations are the same as those in the first example described above (except for step 11, the same operations as those in the flowchart shown in FIG. 1 of the first example are performed), and redundant description is omitted.

  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. 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 2nd example of embodiment of this invention. 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. FIG. 3 is a diagram corresponding to a part A in FIG. 2 for explaining inconvenience caused by changing the shift map. 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

Claims (7)

  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 the target gear ratio, and whether to permit mode switching from the low speed mode to the high speed mode, which is the first function. This determination is 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 braking is performed. A continuously variable transmission characterized in that the mode switching is not permitted when the device is operating.   The continuously variable transmission according to claim 1, wherein mode switching is not always permitted as long as the accelerator opening is 0% and the braking device is operating.   The continuously variable transmission according to claim 1, wherein even when the accelerator opening is 0% and the braking device is operating, mode switching is permitted only when a predetermined condition is satisfied.   The continuously variable transmission according to claim 3, wherein mode switching is permitted when the traveling speed of the vehicle reaches a predetermined value.   The continuously variable transmission according to claim 3, wherein mode switching is permitted when the rotational speed of the drive source reaches a predetermined value.   The predetermined value is set within a range of values in which the state quantity of the drive source does not exceed an allowable value without performing mode switching from the low speed mode to the high speed mode. The continuously variable transmission described in the item.   The continuously variable transmission according to any one of claims 1 to 6, 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.

Images