JP4735066B2 - 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 that is used as an automatic transmission for a vehicle (automobile). Specifically, when the mode is switched between the low speed mode and the high speed mode (when the mode is switched), the change in the gear ratio of the toroidal continuously variable transmission based on the fluctuation of the torque passing through the toroidal continuously variable transmission ( A structure that can suppress the uncomfortable feeling given to the driver and other passengers regardless of the torque shift) is realized at low cost.

  The use of a toroidal type continuously variable transmission as an automobile transmission is described in many publications such as Patent Documents 1 and 2 and Non-Patent Documents 1 and 2, and has been well-known in some implementations. is there. Also, continuously variable transmissions that combine a toroidal type continuously variable transmission and a planetary gear type transmission in order to increase the fluctuation range of the gear ratio have been widely used, for example, as described in Patent Documents 3-7. Are known. 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 is transmitted by a planetary gear type transmission which is a differential unit. 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 7, 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. 14 to 15 show continuously variable transmissions having a mode described in Patent Documents 6 to 7 that can realize a geared neutral state. 14 shows a block diagram of the continuously variable transmission, and FIG. 15 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 to the planetary gear type transmission 5 which is a differential unit, either directly or via the toroidal continuously variable transmission 4. Then, the differential component of the constituent members of the planetary gear type transmission 5 is 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-type continuously variable transmission 4 includes a plurality of input and output disks 10 and 11, each of which is a first and second disk, a plurality of power rollers 12, and a plurality of support members. Each trunnion (not shown), an actuator 13 (FIG. 15), a pressing device 14, and a transmission ratio control unit 15 are provided. 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. To communicate. Each trunnion supports each power roller 12 rotatably.

  The actuator 13 is of a hydraulic type, and the trunnions supporting the power rollers 12 are displaced in the axial directions of the pivots provided at both ends so that the input side disk 10 and the output side The gear ratio with the disk 11 is changed. The pressing device 14 is of a hydraulic type and presses the input side disk 10 and the output side disk 11 in a direction approaching each other. The gear ratio control unit 15 controls the displacement direction and the displacement amount of the actuator 13 so that the gear ratio between the input side disk 10 and the output side disk 11 becomes a desired value.

  In the case of the illustrated example, the transmission ratio control unit 15 includes a controller 16, a stepping motor 17 that is switched based on a control signal from the controller 16, a line pressure control electromagnetic on-off valve 18, and an electromagnetic valve. 19, a shift electromagnetic valve 20, and a control valve device 21 whose operation state can be switched by these members 17 to 20. The control valve device 21 includes a transmission ratio control valve 22, a differential pressure cylinder 23, correction control valves 24a and 24b, and high-speed clutch and low-speed clutch switching valves 25 and 26 (FIG. 15). It is a combination. Of these, the gear ratio control valve 22 controls the supply and discharge of hydraulic pressure to the actuator 13. Further, the differential pressure cylinder 23 is configured to control the transmission ratio control valve so as to correct the transmission ratio of the toroidal type continuously variable transmission 4 according to the torque (passing torque) passing through the toroidal type continuously variable transmission 4. This is for adjusting the switching state of 22. The correction control valves 24 a and 24 b control the supply and discharge of pressure oil to and from the differential pressure cylinder 23. 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. 15) driven by the power extracted from the damper 2 portion is sent to the control valve device 21, the pressing device 14, and the like. That is, the pressure oil sucked from the oil reservoir 28 (FIG. 15) and discharged by the oil pumps 27a and 27b can be adjusted to a predetermined pressure by the pressure regulating valves 29a and 29b. Of these pressure regulating valves 29a and 29b, the adjustment pressure by the pressure regulating valve 29a for adjusting the hydraulic pressure sent to the pressing device 14 and the manual hydraulic pressure switching valve 30 side is used to open and close the line pressure control electromagnetic switching valve 18. It is adjustable based on The pressure oil whose pressure is adjusted by the pressure regulating valves 29a and 29b can be sent to the actuator 13 via the transmission ratio control valve 22, and the stroke of the differential pressure cylinder 23 can be adjusted. The correction control valves 24 a and 24 b can be freely fed based on the opening and closing of the electromagnetic valve 19.

  The pressure oil can be fed into the hydraulic chamber of the low speed clutch 7 or the high speed clutch 8 via the manual hydraulic pressure switching valve 30 and the high speed clutch switching valve 25 or the low speed clutch switching valve 26. It is said. 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 reduction ratio is increased (including an infinite gear ratio (including a geared neutral 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.

  When the continuously variable transmission shown in FIGS. 14 to 15 as described above is operated, the low-speed and high-speed clutches 7 and 8 are switched by switching the shift solenoid valve 20 based on the control signal of the controller 16. The connection / disconnection state is switched to switch between the low speed mode and the high speed mode. At the time of such switching, if the gear ratio of the toroidal type continuously variable transmission 4 matches the theory before and after the mode switching, the mode switching can be performed smoothly without causing a shift shock. However, in the actual case, the gear ratio of the toroidal-type continuously variable transmission 4 changes as the torque passing through the toroidal-type continuously variable transmission 4 changes. This is because the components of the toroidal-type continuously variable transmission 4 are displaced based on the presence of inevitable gaps due to elastic deformation and assembly of each part. That is, when the magnitude or direction of the torque (passing torque) sent through the toroidal continuously variable transmission 4 varies, the displacement direction and displacement of the components of the toroidal continuously variable transmission 4 change. A so-called torque shift occurs in which the gear ratio of the toroidal-type continuously variable transmission 4 changes despite no command for shifting.

FIG. 16 shows the results of an experiment conducted to know the variation state of the transmission ratio of the toroidal type continuously variable transmission accompanying such variation in passing torque. In the experiment, the transmission ratio of the toroidal-type continuously variable transmission is set to 1 (constant speed), the rotational speed of the input shaft is set to 2000 min ^−1, and the temperature of the traction oil is increased in the same manner as when the vehicle is actually running. Performed in the state. Under such conditions, the torque applied to the input shaft was changed between −250 N · m and +350 N · m. The torque was gradually changed to eliminate the influence of inertia as much as possible. The state where the torque applied to the input shaft is negative is a state where torque is transmitted from the output side disk to the input side disk. As is apparent from FIG. 16 showing the results of such an experiment, the transmission ratio of the toroidal-type continuously variable transmission changes to a degree that cannot be ignored by changing the magnitude and direction of the passing torque. In particular, at the moment when the direction of the torque changes (when the input torque fluctuates from 0), the gear ratio changes greatly.

  On the other hand, in the case of a continuously variable transmission that combines a toroidal continuously variable transmission and a differential unit such as a planetary gear transmission, the geared neutral state shown in FIGS. Even if the power split state described in Patent Document 3 can be realized, the direction of torque passing through the toroidal-type continuously variable transmission changes (reverse rotation, reverse rotation) at the moment of mode switching. This point will be described with reference to FIG. FIG. 17 is a continuously variable transmission that can realize the geared neutral state as shown in FIGS. 14 to 15. The speed ratio of the entire continuously variable transmission and the torque that passes through the toroidal continuously variable transmission are shown in FIG. The relationship between the direction (±) and size and the gear ratio of the toroidal continuously variable transmission is shown. In FIG. 17, the solid line a represents the ratio of the torque passing through the toroidal continuously variable transmission to the torque input to the continuously variable transmission, and the broken line b represents the gear ratio of the toroidal continuously variable transmission. Yes. The low speed mode and the high speed mode of the continuously variable transmission are switched at a point c, which is a bent portion of the broken line b. With this mode switching, the magnitude of torque passing through the toroidal continuously variable transmission changes discontinuously, and the direction is reversed.

  As described above, when the magnitude and direction of the torque passing through the toroidal type continuously variable transmission changes with the mode switching, the transmission ratio of the toroidal type continuously variable transmission is changed from the controller by the change of torque. It changes regardless of control (torque shift). When the speed ratio of the toroidal continuously variable transmission changes as described above, the speed ratio of the continuously variable transmission as a whole also changes with the change of the speed ratio. Such a change in the speed ratio of the continuously variable transmission as a whole is not preferable, for example, by rapidly changing the engine speed (rotation speed). More specifically, there is a possibility that the driver and other passengers may feel uncomfortable, for example, when the engine speed suddenly rises (blows up) and causes an unexpected shift shock (torque loss feeling, push feeling). There is.

  On the other hand, Patent Documents 8 and 9 disclose a continuously variable transmission incorporating a toroidal continuously variable transmission (or a belt-type continuously variable transmission) as a technique for smoothly switching modes. A technique is described for reducing the shock at the time of mode switching by performing mode switching (reversal of passing torque) in a state where the transmission ratio of the type continuously variable transmission is maintained at a predetermined value (when no shift command is issued). ing. Patent Document 10 discloses that the rotational speed of power input to the planetary gear type transmission through the toroidal type continuously variable transmission and the planetary gear type speed change without passing through the toroidal type continuously variable transmission. A technique is described in which the clutch is smoothly connected when the mode is switched by switching the mode in a state where the rotational speed of the power input to the machine is matched. Further, Patent Document 11 describes a technique for smoothly performing mode switching by stopping a speed ratio adjusting function based on torque passing through a toroidal-type continuously variable transmission during mode switching.

  However, in the case of the prior art described in each of Patent Documents 8 to 11 as described above, there is a possibility that the inconvenience based on the torque shift as described above cannot be sufficiently prevented. That is, in the case of the prior art described in the above-mentioned Patent Documents 8, 9, and 11, even if the gear ratio is kept at a predetermined value when the mode is switched (even if the gear ratio command is not issued or the gear ratio adjustment function is stopped). ), There is a possibility that the gear ratio will fluctuate based on the torque shift as described above. Further, in the case of the conventional technique described in Patent Document 10, even if the clutch is connected with the rotational speeds being matched, there is a possibility that the transmission gear ratio fluctuates based on the torque shift when the clutch is connected. is there. If the speed ratio changes in this way, the speed ratio of the entire continuously variable transmission changes as the speed ratio changes, which may give the passenger a sense of incongruity as described above.

  On the other hand, Patent Document 12 smoothly connects and disconnects each clutch by simultaneously connecting both the clutch that has been connected and the clutch that has not been connected at the time of mode switching. The technology is described. Further, in Patent Document 13, in a continuously variable transmission that can realize a power split state, the timing for disconnecting the low speed clutch when switching from the low speed mode to the high speed mode, and the time when switching from the high speed mode to the low speed mode are described. There is described a technique for ensuring a time for simultaneously connecting both the low speed and high speed clutches by changing the timing of disconnecting the high speed clutch. In Japanese Patent Application No. 2004-185277, a delay time is set for switching the low-speed clutch switching valve and the high-speed clutch switching valve for switching between connection and disconnection of the low-speed and high-speed clutches. An invention for making time for simultaneous engagement of the clutches is disclosed. Patent Document 14 describes a technique for reducing a shift shock based on a torque shift by correcting (adjusting) a gear ratio of a toroidal continuously variable transmission during mode switching. Further, in Patent Document 15, at the time of mode switching, when the pressure of the clutch to be connected (clutch pressure) becomes a predetermined value or more, or when a predetermined time has elapsed from the start of mode switching control, A technique for correcting the gear ratio of a toroidal type continuously variable transmission by determining that both high speed clutches are simultaneously connected is described.

  The conventional techniques described in Patent Documents 12 to 13 as described above and the technique disclosed in Japanese Patent Application No. 2004-185277 simultaneously connect the low speed clutch and the high speed clutch at the time of mode switching. For this reason, as described in Patent Documents 14 and 15, if the transmission ratio of the toroidal continuously variable transmission is corrected, the change in the transmission ratio based on the torque shift as described above, and thus the continuously variable transmission. It is considered that the change in the speed ratio of the entire apparatus can be reduced to prevent the passenger from feeling uncomfortable as described above. However, in the case of the prior art described in Patent Documents 12 to 15, the structure and mechanism for correcting the gear ratio of the toroidal type continuously variable transmission are complicated, and the cost may increase.

  Further, in Patent Document 16, a mode change is made by correcting (adjusting) the timing of clutch connection / disconnection in anticipation of the change amount (torque shift amount) of the gear ratio of the toroidal-type continuously variable transmission at the time of mode change. A technique for matching the speed ratio of the entire continuously variable transmission before and after is described. If such a technique is employed, the speed ratio of the entire continuously variable transmission can be matched before and after mode switching regardless of torque shift, and the above-described occupant can be prevented from feeling uncomfortable. However, in the case of the prior art described in Patent Document 16, control for matching the speed ratio of the entire continuously variable transmission before and after mode switching becomes sophisticated and complicated, and the cost may increase. is there.

Japanese Patent No. 2734583 JP-A-5-39850 Japanese Patent Laid-Open No. 10-196759 JP 2003-307266 A JP 2000-220719 A JP 2004-225888 A JP 2004-211836 A JP 2002-139140 A JP 2002-276789 A JP-A-11-108147 JP 2004-125119 A Japanese Patent Laid-Open No. 9-210191 JP 2003-207042 A JP 2003-194207 A JP 2002-13627 A JP 2004-116576 A Motoo Aoyama, "Bessed Best Car Red Badge Series 245 / A book that understands the latest mechanics of cars", Sanyusha Co., Ltd./Kodansha Co., Ltd., December 20, 2001, p. 92-93 Hirohisa Tanaka, “Toroidal CVT”, Corona Inc., July 13, 2000

  In view of the circumstances as described above, the present invention, regardless of the change in the gear ratio (torque shift) of the toroidal continuously variable transmission based on the fluctuation of the torque passing through the toroidal continuously variable transmission at the time of mode switching. The invention has been invented to realize a structure capable of suppressing the uncomfortable feeling given to the occupant at a low cost without requiring a complicated device or advanced control.

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.
The controller controls the connection / disconnection of the clutches to change the shift state to either the low speed mode or the high speed mode.
In particular, in the continuously variable transmission according to the present invention, when the mode is switched between the low speed mode and the high speed mode, one of the low speed clutch and the high speed clutch is connected so far. After the clutch that has not been connected is connected, the clutch that has been connected with the other clutch is disconnected before setting the time during which both clutches are connected simultaneously. At the same time, the speed of the entire continuously variable transmission according to the torque shift , which is a change in the gear ratio of the toroidal continuously variable transmission, based on fluctuations in the magnitude and direction of the torque passing through the toroidal continuously variable transmission. In order to make the change in the ratio commensurate with the driving state of the vehicle at that time and to reduce or eliminate the uncomfortable feeling associated with the mode switching, the speed ratio of the entire continuously variable transmission is based on the torque shift. In order to make the changing direction coincide with the direction in which the speed ratio is changed in accordance with the mode switching, the mode switching value of the toroidal continuously variable transmission that starts the mode switching should be performed. The target gear ratio, which is a design value (theoretical value), is shifted according to the traveling state of the vehicle at that time.

In the case of the continuously variable transmission according to the present invention as described above, the magnitude and direction of the torque passing through the toroidal continuously variable transmission fluctuate at the time of mode switching, and the transmission ratio of the toroidal continuously variable transmission is When changed (torque shift), the speed ratio of the continuously variable transmission as a whole changes based on the torque shift in accordance with the traveling state of the vehicle at that time. Specifically, the direction in which the speed ratio of the entire continuously variable transmission changes based on the torque shift coincides with the direction in which the speed ratio changes in accordance with the mode switching. Thus, in order to change the speed ratio of the continuously variable transmission as a whole in accordance with the running state of the vehicle, the torque shift at the time of mode switching is regulated as follows. That is, at the time of switching from the low speed mode to the high speed mode, the torque shift is generated so that the speed ratio of the continuously variable transmission as a whole increases. On the contrary, at the time of switching from the high speed mode to the low speed mode, the torque shift is generated so that the speed ratio of the continuously variable transmission as a whole is reduced. The reason for this is as follows.

  That is, switching from the low speed mode to the high speed mode is performed while the speed ratio of the continuously variable transmission as a whole is increasing. While the speed ratio of the continuously variable transmission as a whole is increasing, if the speed ratio of the continuously variable transmission as a whole decreases as a result of torque shift based on mode switching, a shift shock based on this deceleration occurs. , It may be added as something that the passenger does not expect (for example, a feeling of torque loss), and may give a sense of incongruity. On the other hand, even if the speed ratio of the continuously variable transmission as a whole increases with a torque shift based on the mode switching while the speed ratio of the continuously variable transmission as a whole is increasing, The shift shock based on this speed increase is not added as an unexpected thing of the occupant, and it is difficult to give a sense of incongruity.

On the other hand, switching from the high speed mode to the low speed mode is performed while the speed ratio of the continuously variable transmission as a whole is decelerating. While the speed ratio of the continuously variable transmission as a whole is decelerating, if the speed ratio of the continuously variable transmission as a whole increases with a torque shift based on mode switching, a shift shock based on the increased speed However, it may be added as something that the occupant does not predict (for example, a feeling of pushing out) and may give a sense of discomfort. On the other hand, even if the speed ratio of the continuously variable transmission as a whole decelerates due to the torque shift based on the mode switching while the speed ratio of the continuously variable transmission as a whole is decelerating, this deceleration The shift shock based on is not added as an unexpected thing of the occupant, making it difficult to give a sense of incongruity.
In addition, in the case of the present invention, since the time during which both the high speed clutch and the low speed clutch are simultaneously connected is set, these clutches once transmit power from the mode before these clutches are connected. , And then enter a new mode. For this reason, the reversal of the torque passing through the toroidal type continuously variable transmission at the time of the mode switching is stepwise (in two steps) through the state where both clutches are once connected and the passing torque becomes zero. It happens). For this reason, it is possible to prevent a sudden large torque shift between the previous mode and the new mode in which both clutches are connected, and to moderate the change in the speed ratio of the continuously variable transmission as a whole. The uncomfortable feeling given to the occupants including the driver can be further alleviated.

As described above, if the change in the speed ratio of the continuously variable transmission as a whole due to the torque shift at the time of mode switching can be made according to the state of the vehicle at that time (mode switching direction), specifically, If the direction in which the speed ratio of the entire continuously variable transmission changes based on the torque shift can coincide with the direction in which the speed ratio changes in accordance with the mode switching, the entire continuously variable transmission Even if the speed ratio does not match before and after the mode switching, the uncomfortable feeling given to the occupants including the driver can be suppressed. In order to generate the torque shift so as to change the speed ratio of the continuously variable transmission as described above, for example, as will be described later, the speed ratio of the toroidal continuously variable transmission that starts mode switching is used. This can be done easily by adjusting the value of. For this reason, it is possible to realize a structure that makes it difficult for the occupant to feel a sense of incongruity regardless of torque shift, without requiring a complicated device or advanced control, at a low cost.

When carrying out the present invention, for example, a continuously variable transmission (for example, geared in the low-speed mode) that performs mode switching between the low-speed mode and the high-speed mode in a state where the transmission ratio of the toroidal-type continuously variable transmission is the largest. In the case of a continuously variable transmission that realizes a neutral state and realizes a power split state in a high-speed mode), the shift of the toroidal continuously variable transmission that starts mode switching is performed as in the invention described in claim 2. The ratio value is shifted to the speed increasing side from the target gear ratio.
With this configuration, a change in the gear ratio (torque shift) of the toroidal continuously variable transmission based on fluctuations in the magnitude and direction of torque passing through the toroidal continuously variable transmission at the time of mode switching is desired. Generated on the street. That is, this torque shift is generated so as to increase the speed ratio of the continuously variable transmission as a whole, for example, when switching from the low speed mode to the high speed mode. In addition, when switching from the high speed mode to the low speed mode, the speed ratio of the continuously variable transmission as a whole is reduced. By generating a torque shift in this way, the change in the speed ratio of the continuously variable transmission as a whole accompanying this torque shift can be matched to the vehicle running state (mode switching direction) at that time. Moreover, in order to make the speed ratio of the continuously variable transmission as a whole suitable for the running state in this way, it can be realized at low cost without requiring complicated devices or advanced control.
For example, a continuously variable transmission (for example, a toroidal continuously variable transmission in the low speed mode) that switches the mode between the low speed mode and the high speed mode in a state where the speed ratio of the toroidal continuously variable transmission is the largest. In the case of a continuously variable transmission that transmits power alone and realizes a power split state in high-speed mode), the value of the gear ratio of the toroidal continuously variable transmission that starts mode switching is increased from the target gear ratio. Shift to the speed side or deceleration side. Also in this case, a torque shift is generated so as to match the traveling state of the vehicle at the time of mode switching.

In the case of carrying out the present invention as described above, preferably, as in the invention described in claim 3 , each is a state quantity that affects the change amount of the transmission ratio of the toroidal-type continuously variable transmission . The amount of deviation from the target gear ratio is adjusted (corrected) according to the magnitude of the passing torque, the magnitude of the input torque from the engine, and the vehicle speed .
If comprised in this way, regardless of the state of the vehicle, the change in the speed ratio of the continuously variable transmission as a whole based on the torque shift at the time of mode switching can be adjusted more finely to match the current running state.

Further, when the present invention as described above is carried out, it is preferable to change the timing of outputting a signal indicating that mode switching should be started for each of the low speed clutch and the high speed clutch as in the invention described in claim 4. Thus, the value of the gear ratio of the toroidal continuously variable transmission that starts the mode switching is shifted from the target gear ratio.
With this configuration, it is possible to shift the value of the gear ratio of the toroidal type continuously variable transmission that starts the mode switching from the target gear ratio at a low cost without requiring complicated devices and advanced control. realizable.

When implementing the present invention, preferably, as in the fifth aspect of the present invention, a toroidal that starts mode switching by changing the timing of outputting a signal to start connection to one clutch. The value of the gear ratio of the type continuously variable transmission is shifted from the target gear ratio.
With this configuration, it is possible to shift the value of the gear ratio of the toroidal-type continuously variable transmission that starts the mode switching from the target gear ratio while securing the time for connecting both clutches during the mode switching.

  1 to 4 show an embodiment of the present invention. The feature of the present embodiment is that a change in the gear ratio of the toroidal type continuously variable transmission 4 based on a torque shift (a variation in the magnitude and direction of the torque passing through the toroidal type continuously variable transmission 4) at the time of mode switching. ) In accordance with the traveling state of the vehicle at that time. Since the structure and operation of the other parts are the same as those of the conventional structure shown in FIGS. 14 to 15 described above, the overlapping description will be omitted or simplified, and the following description will focus on the characteristic parts of this embodiment.

  Also in this embodiment, the speed reduction ratio is increased (including the geared neutral state) 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. And a high-speed mode that reduces the reduction ratio. For this purpose, the electromagnetic switching valves 31 for the low speed clutch and the high speed clutch, in which the energized state is controlled based on the control signal of the controller 16, as to whether the low speed and high speed clutches 7 and 8 are connected or disconnected. , 32 can be switched. That is, each of the low-speed clutch and high-speed clutch electromagnetic switching valves 31 and 32 displaces the spool based on the energization of the solenoid. Based on the displacement of the spool, the low-speed clutch and the high-speed clutch 7. By switching the introduction state of the pressure oil into the hydraulic chambers 8 and 8, the connection and disconnection states of the low speed and high speed clutches 7 and 8 are switched.

  For example, when the low-speed clutch 7 is connected and the high-speed clutch 8 is disconnected (when the low-speed mode is realized), the electromagnetic switching valves 31 and 32 for the low-speed clutch and the high-speed clutch are not energized. Then, the spools of the electromagnetic switching valves 31 and 32 are displaced to the right in FIG. 2 (the state of the left half of the circuit representing each spool) based on the elasticity of the springs. As a result, pressure oil is introduced into the hydraulic chamber of the low-speed clutch 7, the low-speed clutch 7 is connected, and the hydraulic chamber of the high-speed clutch 8 leads to the oil reservoir 28. The connection is broken.

  On the other hand, when the low speed clutch 7 is disconnected and the high speed clutch 8 is connected (when the high speed mode is realized), the low speed clutch and high speed clutch electromagnetic switching valves 31 and 32 are energized. The spools of the electromagnetic switching valves 31 and 32 are displaced to the left in FIG. 2 (the state of the right half of the circuit representing each spool) against the spring elasticity. As a result, the hydraulic chamber of the low speed clutch 7 communicates with the oil reservoir 28, the low speed clutch 7 is disconnected, and pressure oil is introduced into the hydraulic chamber of the high speed clutch 8. The high speed clutch 8 is connected.

  Further, when both the low speed and high speed clutches 7 and 8 are disconnected (when the neutral state is realized), the low speed clutch electromagnetic switching valve 31 is energized and the spool of the electromagnetic switching valve 31 is turned on. 2 is displaced to the left (right half state) in FIG. 2 against the elasticity of the spring, and the high-speed clutch electromagnetic switching valve 32 is deenergized, and the spool of the electromagnetic switching valve 32 is connected to the spring. Based on the elasticity, it is displaced to the right (the state of the left half) in FIG. As a result, the hydraulic chamber of the low speed clutch 7 communicates with the oil reservoir 28, the low speed clutch 7 is disconnected, and the hydraulic chamber of the high speed clutch 8 communicates with the oil reservoir 28. 8 is disconnected.

  In the case of the present embodiment, the controller 16 includes the low speed clutch 7 and the high speed clutch 8 in order to create time for simultaneously connecting the low speed and high speed clutches 7 and 8 when the mode is switched. One of the clutches has a function of disconnecting a clutch that has not been connected until then, and the other clutch is disconnected until then. That is, when switching from the low speed mode to the high speed mode, the high speed clutch 8 is connected and then the low speed clutch 7 is disconnected, and when the mode is switched from the high speed mode to the low speed mode. The high speed clutch 8 is disconnected after the low speed clutch 7 is connected. In this way, in order to create time for simultaneously connecting the low speed and high speed clutches 7 and 8 at the time of mode switching, the controller 16 can connect and disconnect the clutches 7 and 8 independently as in this embodiment. In addition, the structure disclosed in the aforementioned Japanese Patent Application No. 2004-185277 can be employed. In any case, when the mode is switched, both the low speed and high speed clutches 7 and 8 are once connected at the same time to ensure that the passing torque of the toroidal-type continuously variable transmission 4 becomes 0, so that And sudden torque shift between the new mode and the new mode is prevented.

  Further, in the case of this embodiment, when the mode is switched between the low speed mode and the high speed mode, the change in the speed ratio of the continuously variable transmission as a whole due to the torque shift is commensurate with the traveling state of the vehicle at that time. To. Before describing the characteristic part of the present embodiment, first, the change in the speed ratio of the entire continuously variable transmission according to the torque shift at the time of mode switching will be described with reference to FIGS. To do. 5 to 9 show the shift command signal output from the controller 16 when the low speed mode is switched to the high speed mode during acceleration (with the accelerator pedal depressed), and the toroidal type continuously variable transmission 4. The relationship between the gear ratio and the speed ratio of the continuously variable transmission as a whole is schematically shown. That is, the speed ratio of the toroidal type continuously variable transmission 4 is decelerated to a value for mode switching (mode switching point) based on the speed change command signal of the controller 16 (the speed ratio of the entire continuously variable transmission is increased). After the high speed clutch 8 is connected and then the low speed clutch 7 is disconnected, the speed ratio of the toroidal continuously variable transmission 4 is increased (the speed ratio of the continuously variable transmission as a whole is increased). ). In each of these figures, the gear ratio value (mode switching point) for starting mode switching is different.

  That is, in the continuously variable transmission having a design mode switching point of 0.45, actual mode switching is performed in FIG. 5 with a value (for example, on the deceleration side) smaller than the design value (0.45) (for example, on the deceleration side). FIG. 6 shows a case of starting at 0.43), FIG. 6 shows a case of starting with the above design value, and FIG. 7 shows a value (for example, 0.455) slightly larger (acceleration side) than the above design value. 8 starts with a value larger than the design value (eg, 0.46 to 0.48), and FIG. 9 shows a value larger than the design value (eg, 0). .52) respectively. Also, the thin line α in each figure indicates the state in which torque does not pass through the toroidal type continuously variable transmission 4 (a state in which the constituent members of the toroidal type continuously variable transmission 4 are not displaced and elastically deformed based on the passing torque). The relationship (ideal relationship) between the gear change command signal and the gear ratio of the toroidal-type continuously variable transmission 4 is shown.

  On the other hand, during actual operation, for example, during acceleration, the constituent members are displaced and elastically deformed based on the torque input from the engine 1 and passing through the toroidal continuously variable transmission 4. As the components are displaced and elastically deformed, the relationship between the gear change command signal and the gear ratio of the toroidal-type continuously variable transmission 4 is the fine line as shown by the thick lines β and γ in each figure. Deviation from α. Specifically, since the direction of the torque passing through the toroidal-type continuously variable transmission 4 is reversed in the low speed mode and the high speed mode (reversed, positive and negative are reversed), the direction of deviation with respect to the thin line α is Different in each mode. For example, during acceleration in the low speed mode, as shown by the thick line β, it is below the thin line α. In this state, a pair of hydraulic chambers 33a and 33b provided in a hydraulic actuator 13 that displaces a support member (trunnion) that supports the power roller 12, which is a value corresponding to the passing torque, in the axial direction of the pivot. The differential pressure between becomes negative. Further, during acceleration in the high speed mode, as shown by the thick line γ, it is above the thin line α. In this state, the differential pressure between the hydraulic chambers 33a and 33b of the actuator 13 becomes positive.

  The circles (◯) in FIGS. 5 to 9 indicate when the connection of the high speed clutch 8 which is one of the clutches is started, and the square marks (□) indicate the high speed clutch 8 and the low speed clutch. The time when both clutches 7 and 8 with the clutch 7 are simultaneously connected is also indicated by the triangle (△), which indicates the time when the connection of the low speed clutch 7 which is the other clutch is disconnected (completely). Yes. The solid arrows in FIGS. 5 to 9 indicate changes in the speed ratio of the toroidal continuously variable transmission 4 and the speed ratio of the continuously variable transmission based on changes in torque passing through the toroidal continuously variable transmission 4. (Torque shift) Similarly, the broken line arrow indicates the gear ratio of the toroidal type continuously variable transmission 4 and the continuously variable transmission of the continuously variable transmission based on the displacement of the rod of the actuator 13 by the shift command signal output from the controller 16. The change in speed ratio is shown respectively.

  For example, in the case of FIG. 5 in which the mode switching point is smaller than the designed value of 0.45 (in the case of slow switching), the gear ratio of the toroidal continuously variable transmission 4 is designed according to the above design. After passing the mode switching point and reaching the point (e.g., 0.43), the connection of the high speed clutch 8 which is the clutch to be connected is started, and the high speed clutch 8 and the low speed clutch that has been connected so far are started. Both clutches 7 and 8 with the clutch 7 are connected simultaneously. In this manner, the speed ratio of the toroidal-type continuously variable transmission 4 from the start of the connection of the high speed clutch 8 to the simultaneous connection of the clutches 7 and 8 is determined from the point A to the design mode. It changes (torque shift) to point B, which is the switching point. With this change, the speed ratio of the continuously variable transmission as a whole also changes from point C to point D. Such a change in the speed ratio of the continuously variable transmission as a whole occurs in the direction of decelerating the speed ratio. For this reason, the rotational speed of the engine 1 increases rapidly, which may cause a shift shock that gives the passenger a sense of incongruity. Further, since the change in the gear ratio of the toroidal continuously variable transmission 4 is the same as the direction in which the gear ratio changes based on acceleration in the low speed mode, the passing torque of the toroidal continuously variable transmission 4 is increased. . Such an increase in passing torque is not preferable because it increases the torque fluctuation difference during mode switching.

On the other hand, after the low speed and high speed clutches 7 and 8 are connected as described above, when the connection of the low speed clutch 7 which is a clutch to be disconnected is disconnected, the toroidal continuously variable transmission 4 is The passing torque is reversed with respect to the value of the low speed mode so far (positive and negative are reversed). Based on such a change in passing torque, the transmission ratio of the toroidal-type continuously variable transmission 4 changes (torque shift) from point B to point E on the thick line 繃. With this change, the speed ratio of the continuously variable transmission as a whole also changes from point to point. Such a change in the speed ratio of the continuously variable transmission as a whole occurs in the direction of decelerating in the same manner as described above, which may cause a shift shock that gives the passenger a sense of incongruity. Note that when the low speed clutch 7 is disconnected as described above, the passing torque is reversed, so that the passing torque increases until the change in the gear ratio based on the reversal of the passing torque is eliminated. There is nothing to do.

Further, in the case of FIG. 6 where the mode switching point is a design value (in the case of switching according to the design value), a point (0) where the gear ratio of the toroidal continuously variable transmission 4 is the mode switching point. .45), the connection of the high speed clutch 8 is started, and both the high speed clutch 8 and the low speed clutch 7 connected so far are simultaneously connected. From the start of the connection of the high speed clutch 8 to the time when the clutches 7 and 8 are simultaneously connected, the transmission ratio of the toroidal continuously variable transmission is the mode switching point (0. 45) does not change, and the speed ratio of the continuously variable transmission does not change. For this reason, the shift shock that gives the passenger a sense of incompatibility does not occur when the low speed and high speed clutches 7 and 8 are simultaneously connected. On the other hand, after the low speed and high speed clutches 7 and 8 are connected as described above, when the connection of the low speed clutch 7 which is a clutch to be disconnected is disconnected, the clutch passes through the toroidal continuously variable transmission 4. The torque of the toroidal-type continuously variable transmission 4 changes from the to point to a point on the thick line （(torque). shift. With this change, the speed ratio of the continuously variable transmission as a whole changes from the re-point to the n-point, and there is a possibility that a shift shock that gives the passenger a sense of incongruity as in the case described above may occur.

Further, in the case of FIG. 7 where the mode switching point is slightly larger than the design value (when switching a little earlier), the gear ratio of the toroidal-type continuously variable transmission 4 is designed for mode switching. At a point (e.g., 0.455) before reaching the point, the connection of the high-speed clutch 8 is started, and both the high-speed clutch 8 and the low-speed clutch 7 that has been connected so far are connected. Connected simultaneously. From the start of the connection of the high-speed clutch 8 to the simultaneous connection of the clutches 7 and 8, the transmission ratio of the toroidal-type continuously variable transmission 4 varies from the point to the design mode. The point changes to the switching point (torque shift). In accordance with this change, the speed ratio of the continuously variable transmission as a whole also changes from the W point to the F point. However, such a change in the speed ratio of the continuously variable transmission as a whole occurs in the direction of increasing the speed ratio. That is, since the rotational speed of the engine 1 decreases with this increase in speed, no shift shock that gives the passenger a sense of incongruity does not occur. On the other hand, after the low speed and high speed clutches 7 and 8 are connected as described above, when the connection of the low speed clutch 7 which is a clutch to be disconnected is disconnected, the toroidal continuously variable transmission 4 is The passing torque is reversed with respect to the value of the low speed mode so far (the sign is reversed), and the transmission ratio of the toroidal type continuously variable transmission 4 changes from the above point to the point on the thick line 太 ( Torque shift). Along with this change, the speed ratio of the continuously variable transmission as a whole changes from the above point to a point, and there is a possibility that a shift shock that gives the passenger a sense of incongruity as in the case described above may occur.

Further, in the case of FIG. 8 where the mode switching point is larger than the designed value (in the case of earlier switching), the transmission ratio of the toroidal continuously variable transmission 4 is the above-mentioned point of FIG. At the point before reaching (for example, 0.46 to 0.48), the connection of the high speed clutch 8 is started, and both the clutch 7 of the high speed clutch 8 and the low speed clutch 7 connected so far, 8 are connected simultaneously. Thus, the gear ratio of the toroidal-type continuously variable transmission 4 is changed from the above point to the design mode switching from the start of the connection of the high-speed clutch 8 until the clutches 7 and 8 are simultaneously connected. The point changes to the point (torque shift). With this change, the speed ratio of the continuously variable transmission as a whole also changes from a point to a point. However, since the change in the speed ratio of the continuously variable transmission as a whole occurs in the direction of increasing the speed ratio, as in the case of FIG. 7 described above, it becomes a shift shock that gives the passenger a sense of incongruity. Hateful. Further, after the low speed and high speed clutches 7 and 8 are connected as described above, when the connection of the low speed clutch 7 which is a clutch to be disconnected is disconnected, the toroidal continuously variable transmission 4 is The passing torque is reversed with respect to the value of the low speed mode so far (positive and negative are reversed). However, even if the torque is reversed in this way, the gear ratio of the toroidal type continuously variable transmission 4 does not change at the above-mentioned point on the shoreline, and the speed ratio of the entire continuously variable transmission does not change. For this reason, there is no shift shock that gives the passenger a sense of incongruity.

  In the case of FIG. 9 where the mode switching point is further larger than the design value (in the case of earlier switching), the transmission ratio of the toroidal continuously variable transmission 4 is set to the above-mentioned point in FIG. The connection of the high speed clutch 8 is started at a point before reaching (for example, 0.52), and both the high speed clutch 8 and the low speed clutch 7 connected so far are simultaneously connected. Is done. From the start of the connection of the high-speed clutch 8 until the clutches 7 and 8 are simultaneously connected, the transmission ratio of the toroidal continuously variable transmission 4 is determined from the above point to the design mode. It changes (torque shift) to point La, which is the switching point. In accordance with this change, the speed ratio of the continuously variable transmission as a whole also changes from point m to point c. However, such a change in the speed ratio of the continuously variable transmission as a whole occurs in the direction of increasing the speed ratio, and as in the case of FIG. Hateful. Further, since the change in the gear ratio of the toroidal continuously variable transmission 4 is opposite to the direction in which the gear ratio changes based on the acceleration in the low speed mode, the passing torque of the toroidal continuously variable transmission 4 increases. There is nothing, and the torque fluctuation difference at the time of mode switching does not increase.

On the other hand, after the low speed and high speed clutches 7 and 8 are connected as described above, when the connection of the low speed clutch 7 which is a clutch to be disconnected is disconnected, the toroidal continuously variable transmission 4 is The passing torque is reversed with respect to the value of the low speed mode so far (positive and negative are reversed). Then, based on such a change in passing torque, the transmission ratio of the toroidal type continuously variable transmission 4 changes (torque shift) from the La point to the saddle point on the thick line 繃. In accordance with this change, the speed ratio of the continuously variable transmission as a whole also changes from the c point to the no point. Such a change in the speed ratio of the continuously variable transmission as a whole occurs in the direction of increasing the speed in the same manner as described above, and therefore is unlikely to be a shift shock that gives the passenger a sense of incongruity. However, since the passing torque is reversed after the low speed clutch 7 is disconnected, until the change in the gear ratio of the toroidal type continuously variable transmission 4 is eliminated (until it becomes on the shoreline), This passing torque increases. Such an increase in passing torque may cause a feeling of strangeness in the behavior (driving feeling) of the vehicle, which is not preferable.

  As is apparent from FIGS. 5 to 9 as described above, the value of the gear ratio (mode switching point) of the toroidal-type continuously variable transmission 4 for starting mode switching is a target value that is a design value for mode switching. By shifting an appropriate amount as shown in FIG. 8 from the gear ratio (for example, 0.45), the change in the speed ratio of the continuously variable transmission based on the torque shift is commensurate with the driving state of the vehicle, that is, to the passenger. It can be made less likely to cause a shift shock that gives a sense of incongruity. Therefore, in the case of the present embodiment, as shown in FIGS. 3 and 4, the gear ratio for performing the mode switching is shifted as shown in FIG. FIG. 3A of FIGS. 3 and 4 shows a state at the time of switching from the low speed mode (acceleration) to the high speed mode when the accelerator pedal is depressed. Correspond. 3 (B) shows the state when switching from the low speed mode (during coasting) to the high speed mode with the accelerator pedal released, and FIG. 4 (A) shows the state with the accelerator pedal released. FIG. 4 (B) shows the state at the time of switching from the high speed mode (during deceleration) to the low speed mode when the accelerator pedal is depressed (during kick down). Each state is shown.

  Thus, in the case of the present embodiment, the value of the gear ratio of the toroidal-type continuously variable transmission 4 that starts the mode switching is changed from the target gear ratio (for example, 0.45) that is a design value for the mode switching. , It is shifted to the speed increasing side (for example, 0.46 to 0.48). For this reason, the timing at which a signal indicating that mode switching should be started is output from the controller 16 is made faster than when the mode switching is started at the target gear ratio. That is, as shown in FIG. 3, when switching from the low speed mode to the high speed mode, the timing for outputting the signal indicating that the connection to the high speed clutch 8 should be started is the time when the mode switching is started at the target gear ratio. It is faster than. Also, as shown in FIG. 4, when switching from the high speed mode to the low speed mode, the timing for outputting a signal indicating that the connection to the low speed clutch 7 should be started is the time when the mode switching is started at the target gear ratio. It is faster than. It should be noted that the high speed clutch 8 (in the case of FIG. 3) or the low speed clutch 7 (in the case of FIG. 4) starts to be engaged (the shift amount with respect to the target speed ratio), in other words, the high speed clutch 8. Alternatively, the timing at which a signal indicating that the connection to the low speed clutch 7 should be started (the amount of deviation with respect to the case of switching at the target gear ratio) affects the amount of change in the gear ratio of the toroidal continuously variable transmission 4. Adjustment (correction) is made according to the state quantity (for example, the magnitude of the passing torque, the magnitude of the input torque from the engine 1, the vehicle speed, etc.).

  For example, in the case of FIG. 3A showing the state when switching from the low speed mode (accelerating) to the high speed mode with the accelerator pedal depressed, the toroidal is similar to the case of FIG. When the speed ratio of the type continuously variable transmission 4 is decelerated along the β line, the high speed clutch 8 is at a point (eg, 0.46 to 0.48) before reaching the target speed ratio (0.45). Connection is started. When the high-speed clutch 8 is connected in this way, the gear ratio changes from point A to point B (torque shift). As described with reference to FIG. 8, the speed ratio of the continuously variable transmission as a whole. Change (change from point C to point D) is unlikely to be a shift shock that makes the passenger feel uncomfortable. Even when the low speed clutch 7 which is a clutch to be disconnected is disconnected, the transmission ratio of the toroidal type continuously variable transmission 4 remains unchanged at the above-mentioned point on the γ-ray, and the continuously variable transmission. The overall speed ratio does not change. For this reason, it is difficult for a shift shock that gives the passenger an uncomfortable feeling.

  Further, in the case of FIG. 3B showing the state of switching from the low-speed mode to the high-speed mode (during inertial running) with the accelerator pedal released, the transmission ratio of the toroidal continuously variable transmission 4 is When decelerating along the β line, the connection of the high speed clutch 8 is started at a point (e.g., 0.46 to 0.48) before reaching the target gear ratio. In such a state in which the accelerator pedal is released (during coasting), the direction of the torque passing through the toroidal-type continuously variable transmission 4 is opposite to that during acceleration in FIG. 3 (A). . That is, the differential pressure between the pair of hydraulic chambers 33a and 33b constituting the actuator 13 corresponding to the torque (passing torque) passing through the toroidal-type continuously variable transmission 4 is the low speed shown in FIG. While it is negative in the mode state, it is 0 to positive in the low speed mode state of FIG. Further, the differential pressure becomes positive in the high speed mode state of FIG. 3A, whereas it becomes 0 to negative in the high speed mode state of FIG. 3B. Therefore, in FIG. 3B, in the low speed mode, the thick line β representing the relationship between the transmission ratio of the toroidal type continuously variable transmission 4 and the shift command signal is above the thin line α representing the ideal relationship. In the high-speed mode state, the thick line γ is below the thin line α {the positional relationship of the thick lines β and γ with respect to the thin line α is reversed in FIG. 3A}.

  When switching from the low speed mode (during inertial running) to the high speed mode with such an accelerator pedal released, the speed ratio of the toroidal-type continuously variable transmission 4 is at point i as described above. The connection is started, and both the high-speed clutch 8 and the low-speed clutch 7 connected so far are simultaneously connected. Thus, the gear ratio of the toroidal-type continuously variable transmission 4 is changed from the above point (i) to the design mode switching from the start of the connection of the high speed clutch 8 to the simultaneous connection of the clutches 7 and 8. Changes to point B (torque shift). With this change, the speed ratio of the continuously variable transmission as a whole also changes from point C to point D. However, such a change in the speed ratio of the continuously variable transmission as a whole occurs in the direction of increasing the speed ratio. That is, since the rotational speed of the engine 1 is lowered, it is difficult to be a shift shock that gives the passenger a sense of incongruity. Further, after the low speed and high speed clutches 7 and 8 are connected as described above, when the connection of the low speed clutch 7 which is a clutch to be disconnected is disconnected, the toroidal continuously variable transmission 4 is The passing torque is reversed with respect to the value of the low speed mode so far, and the gear ratio of the toroidal type continuously variable transmission 4 changes from the point B to the point E. Along with this change, the speed ratio of the continuously variable transmission as a whole also changes from point D to point F. However, since the change in the speed ratio of the continuously variable transmission as a whole occurs in the direction of increasing the speed ratio, a shift shock that makes the passenger feel uncomfortable is unlikely to occur as in the case described above.

  Further, in the case of FIG. 4 (A) showing the state at the time of switching from the high speed mode (during deceleration) to the low speed mode with the accelerator pedal released, the gear ratio of the toroidal continuously variable transmission 4 is γ. When the vehicle decelerates along the line, the connection of the low speed clutch 7 is started at a point (e.g., 0.46 to 0.48) before reaching the target gear ratio. In such a state where the accelerator pedal is released (decelerated), the direction of torque passing through the toroidal-type continuously variable transmission 4 depresses the accelerator shown in FIG. 3A (accelerating). It is the reverse of the state {same as FIG. 3B}. That is, the differential pressure between the pair of hydraulic chambers 33a and 33b constituting the actuator 13 corresponding to the torque (passing torque) passing through the toroidal continuously variable transmission 4 becomes negative in the high speed mode, It becomes positive in the low-speed mode {the positional relationship of the thick lines β and γ with respect to the thin line α is opposite to that in FIG. 3A}.

  When switching from the high-speed mode (during deceleration) to the low-speed mode with the accelerator pedal released, the low-speed clutch 7 is connected at the point where the gear ratio of the toroidal-type continuously variable transmission 4 is at point i as described above. Is started, and both the low-speed clutch 7 and the high-speed clutch 8 connected so far are simultaneously connected. In this way, the speed ratio of the toroidal-type continuously variable transmission 4 is changed from the point a to the design mode switching from the start of the connection of the low speed clutch 7 until the clutches 7 and 8 are simultaneously connected. Changes to point B (torque shift). With this change, the speed ratio of the continuously variable transmission as a whole also changes from point C to point D. However, such a change in the speed ratio of the continuously variable transmission as a whole occurs in the direction of decelerating the speed ratio. For this reason, since the rotational speed of the engine 1 increases and a feeling of deceleration can be obtained, it is difficult to give the passenger a sense of incongruity. Further, after the low speed and high speed clutches 7 and 8 are connected as described above, when the connection of the high speed clutch 8 which is a clutch to be disconnected is disconnected, the toroidal continuously variable transmission 4 is connected. The passing torque is reversed with respect to the value of the high speed mode so far. However, even if the torque is reversed in this way, the speed ratio of the toroidal type continuously variable transmission 4 does not change at the point B on the β line, and the speed ratio of the entire continuously variable transmission does not change. For this reason, there is no shift shock that gives the passenger an uncomfortable feeling.

  Further, in the case of FIG. 4B showing the state of switching from the high speed mode (during kick down) with the accelerator pedal depressed (during kick down), the transmission ratio of the toroidal type continuously variable transmission 4 is When the speed is reduced along the γ-ray, the connection of the low speed clutch 7 is started at a point (e.g., 0.46 to 0.48) before reaching the target gear ratio. In the state where the accelerator pedal is released (decelerated), the torque direction passing through the toroidal type continuously variable transmission 4 is the case where the accelerator shown in FIG. 4A is released (decelerated). And reverse {same as FIG. 3A}. That is, the differential pressure between the pair of hydraulic chambers 33a and 33b constituting the actuator 13 corresponding to the torque (passing torque) passing through the toroidal type continuously variable transmission 4 becomes positive in the high speed mode, and It becomes negative in the low speed mode {the positional relationship of the thick lines β and γ with respect to the thin line α is opposite to that in FIG. 4A}.

  When switching from the high speed mode to the low speed mode (during kickdown) with the accelerator pedal depressed, the speed ratio of the toroidal-type continuously variable transmission 4 is at point i as described above. The connection is started, and both the low-speed clutch 7 and the high-speed clutch 8 connected so far are simultaneously connected. In this way, the speed ratio of the toroidal-type continuously variable transmission 4 is changed from the point a to the design mode switching from the start of the connection of the low speed clutch 7 until the clutches 7 and 8 are simultaneously connected. Changes to point B (torque shift). With this change, the speed ratio of the continuously variable transmission as a whole also changes from point C to point D. However, such a change in the speed ratio of the continuously variable transmission as a whole occurs in a direction in which the speed ratio is decelerated, so that it is difficult to give the passenger a sense of incongruity as in the case described above. Further, after the low speed and high speed clutches 7 and 8 are connected as described above, when the connection of the high speed clutch 8 which is a clutch to be disconnected is disconnected, the toroidal continuously variable transmission 4 is connected. The passing torque is reversed with respect to the value of the high speed mode so far, and the gear ratio of the toroidal continuously variable transmission 4 changes from the point B to the point E. Along with this change, the speed ratio of the continuously variable transmission as a whole also changes from point D to point F. However, such a change in the speed ratio of the continuously variable transmission as a whole occurs in the direction of decelerating the speed ratio, so that it is difficult for the passenger to feel uncomfortable.

  In the case of the present embodiment as described above, the magnitude and direction of the torque passing through the toroidal continuously variable transmission 4 fluctuate at the time of mode switching, and the gear ratio of the toroidal continuously variable transmission 4 changes ( Torque shift), the speed ratio of the entire continuously variable transmission changes according to the traveling state of the vehicle at that time based on the torque shift. That is, the torque shift at the time of mode switching is as follows: when switching from the low speed mode to the high speed mode, the speed ratio of the entire continuously variable transmission is in the speed increasing direction; when switching from the low speed mode to the high speed mode, the above stepless The torque shift is generated so that the speed ratio of the entire transmission changes in the deceleration direction. For this reason, even when the speed ratio of the entire continuously variable transmission changes with torque shift at the time of mode switching, it is possible to prevent a shift shock based on this change from being added as unexpected by the occupant. In other words, even if the speed ratio of the continuously variable transmission does not match before and after mode switching, it is possible to make it difficult for the driver and other passengers to feel uncomfortable. Further, as described above, changing the speed ratio of the continuously variable transmission (generating a desired torque shift) is the value of the gear ratio of the toroidal continuously variable transmission 4 that starts mode switching (connection of the clutch). It can be done easily by adjusting the timing of starting. For this reason, it is possible to realize a structure that makes it difficult for the occupant to feel a sense of incongruity regardless of torque shift, without requiring a complicated device or advanced control, at a low cost.

  FIGS. 10 to 13 show changes in acceleration and the like applied to the vehicle from when the vehicle is stopped to acceleration to about 50 Km / h, after that, after inertial running and after the brake pedal is depressed. Show. Of these FIGS. 10 to 13, FIGS. 10 and 11 show the case where mode switching corresponding to the present embodiment is performed, and FIG. 12 shows the case where mode switching corresponding to FIG. 5 is performed. Reference numeral 13 denotes a case where mode switching corresponding to FIG. 9 is performed. In other words, FIG. 10 shows that the acceleration ratio of the toroidal continuously variable transmission 4 that starts the mode switching is 0.46 with strong acceleration (up to about 0.33 G) with the accelerator opening being about 30%. It shows the case of (early switching). FIG. 11 shows normal acceleration (about 0.1 to 0.2 G) with an accelerator opening of about 10% and a gear ratio for starting mode switching to 0.46 (early switching). Shows the case. FIG. 12 shows a normal acceleration (about 0.1 to 0.2 G) with an accelerator opening of about 10%, and a gear ratio for starting mode switching is set to 0.43 (later switching). Shows the case. FIG. 13 shows a normal acceleration (about 0.1 to 0.2 G) with an accelerator opening of about 10%, and a gear ratio for starting mode switching is set to 0.52 (switching too early). ) Shows the case. In any case, the gear ratio of the toroidal-type continuously variable transmission 4 to be switched in design mode is 0.45.

  10-13, the rotational speed of the input side disk 10 (IDREV [min-1]: left vertical axis) is a fine dotted line, and the rotational speed of the output side disk 11 (ODREV [min-1]: left) The vertical axis) is a thin two-dot chain line, the transmission ratio of the toroidal type continuously variable transmission 4 (eCVU [ratio]: left vertical axis × 10000) is a thick solid line, and a pair of hydraulic chambers 33a, 33b of the actuator 13 are The differential pressure between them (dP [KPa]: left vertical axis) is indicated by a thin broken line. Also, the driving mode {MODE [L (low speed mode) / H (high speed mode)]} is a thick two-dot chain line, and the vehicle speed (SPEED [km / h]: left vertical axis x 100) is a thin three-dot chain line. The opening (ACCEL [%]: right vertical axis +200) is a thick four-dot chain line, and the brake pedal depression state (F / B [ON / OFF]) is a thick three-dot chain line. In addition, the switching state (Low SOL [ON / OFF]) of the low-speed clutch electromagnetic switching valve 31 is indicated by a thick five-dot chain line, and the switching state (High SOL [ON / OFF]) of the high-speed clutch electromagnetic switching valve 32 is indicated by a thick broken line. And the step position (S / M [Step]: right vertical axis) of the stepping motor 17 is a bold one-dot chain line. Further, the hydraulic pressure in the hydraulic chamber of the low speed clutch 7 (K1 [KPa]: right vertical axis × 10) is a thin four-dot chain line, and the hydraulic pressure in the hydraulic chamber of the high speed clutch 8 (K2 [KPa]: right vertical axis × 10). ) Is a thin five-dot chain line, and acceleration (Acceleration [G]: right vertical axis × 10) is a thin solid line. The horizontal axis is time [Sec], and the transmission ratio eCVU (mode switching point) of the toroidal continuously variable transmission 4 for mode switching is 0.46.

  As is apparent from FIGS. 10 to 13, if the mode is switched at the timing as in the present embodiment, it is possible to prevent the occurrence of a shift shock that gives the passenger an uncomfortable feeling. For example, in FIGS. 10 and 11, when switching from the low speed mode to the high speed mode, the transmission ratio of the toroidal continuously variable transmission 4 is reduced as shown in A, but the rotational speed of the engine 1 is suddenly changed as shown in B. (There is no sense of incongruity because the rotation speed decreases even if it fluctuates). Further, even when the high speed mode is switched to the low speed mode, the gear ratio is reduced as shown in C, but the rotational speed of the engine 1 does not fluctuate rapidly as shown in D {the rotational speed increases even if fluctuated ( There is no sense of incongruity). For this reason, the acceleration representing the behavior of the vehicle does not change abruptly as shown by the solid lines E and F in the figure. Further, the differential pressure between the pair of hydraulic chambers 33a and 33b constituting the actuator 13, which is a value corresponding to the passing torque of the toroidal-type continuously variable transmission 4, is also an undershoot (G in FIG. 12 described below) Overshoot (H in FIG. 13 described below) does not occur, and smooth switching can be performed.

  On the other hand, in FIG. 12, when switching from the low speed mode to the high speed mode, the gear ratio of the toroidal-type continuously variable transmission 4 increases (0.43 → 0.44) as shown in A, and the rotational speed of the engine Goes up and down as shown in B (after going down a little). Also, when switching from the high speed mode to the low speed mode, the gear ratio is reduced as shown at C, and the rotational speed of the engine 1 goes up and down as shown at D (after being slightly lowered and then raised). For this reason, there is a possibility that the driver feels uncomfortable when the mode is switched. In addition, undershoot G is also observed when the differential pressure between the pair of hydraulic chambers 33a and 33b constituting the actuator 13 is switched from the low speed mode to the high speed mode. Since such a change in the differential pressure is a change in the direction of increasing the passing torque, there is a possibility that the feeling becomes heavy. In FIG. 13, when switching from the low speed mode to the high speed mode, the gear ratio of the toroidal continuously variable transmission 4 increases (0.52 → 0.42) as shown in A. Since the rotational speed decreases, there is little shift shock. However, an overshoot H is seen in the differential pressure between the pair of hydraulic chambers 33a and 33b constituting the actuator 13. For this reason, the vehicle behavior (driving feeling) may be uncomfortable.

  In the case of this embodiment, the connection state of the low speed clutch 7 and the high speed clutch 8 is determined based on the switching of the electromagnetic switching valves 31 and 32 for the low speed clutch and the high speed clutch controlled by the controller 16. Each can be switched independently. In this way, as a structure for independently switching the connection / disconnection state of the low speed and high speed clutches 7 and 8, the low speed high speed clutch and the high speed clutch electromagnetic switching valves 31 and 32 respectively provide the low speed and high speed clutches. In addition to controlling the hydraulic pressure fed to the hydraulic chambers of the clutches 7 and 8, it can also be controlled by an electromagnetic proportional valve or an actuator such as a motor. Further, the connection and disconnection of the low speed and high speed clutches 7 and 8 can be directly controlled by an actuator such as a motor or a switching valve. In short, any structure can be adopted as long as the connection states of the low speed and high speed clutches 7 and 8 can be switched independently.

  If the time for switching both the low-speed and high-speed clutches 7 and 8 at the same time can be secured at the time of mode switching, the connection state of the low-speed and high-speed clutches 7 and 8 as in this embodiment is switched independently. Other than the structure can be adopted. For example, as disclosed in the aforementioned Japanese Patent Application No. 2004-185277, a delay time is set for switching, for example, by providing a resistance to the hydraulic piping, thereby securing a time for the clutches 7 and 8 to be simultaneously connected. You may do it. In any case, the gear ratio of the toroidal-type continuously variable transmission 4 for starting mode switching (timing for starting mode switching) is shifted (to the speed increasing side) from the designed mode switching point (early timing). As a result, the change in the speed ratio of the entire continuously variable transmission based on the torque shift at the time of mode switching is matched to the traveling state of the vehicle at that time.

  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 present invention was 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. 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. . Further, it can be used not only as an automatic transmission for automobiles but also as a transmission for various industries. The structure of the toroidal continuously variable transmission may be either a half toroidal type or a full toroidal type.

1 is a block diagram of a continuously variable transmission that shows Embodiment 1 of the present invention. FIG. The hydraulic circuit diagram which shows the hydraulic mechanism integrated in this continuously variable transmission. The diagram which shows the operation | movement characteristic of Example 1, and shows the relationship between the gear ratio of the toroidal type continuously variable transmission and the speed ratio of the whole continuously variable transmission, and the shift command signal when switching from the low speed mode to the high speed mode. . FIG. 4 is a diagram similar to FIG. 3 when switching from the high speed mode to the low speed mode. Of the toroidal-type continuously variable transmission and the speed ratio of the entire continuously variable transmission and the shift command signal when the gear ratio at which mode switching is started is set to a lower speed side (slower switching) than the design value. Diagram showing the relationship. FIG. 6 is a diagram similar to FIG. 5, showing a case where the gear ratio for starting mode switching is as designed. FIG. 6 is a diagram similar to FIG. 5, showing a case where the gear ratio at which mode switching is started is slightly increased from the design value (switching slightly earlier). FIG. 6 is a diagram similar to FIG. 5, showing a case where the gear ratio for starting mode switching is set to be higher than the design value (earlier switching). FIG. 6 is a diagram similar to FIG. 5, showing a case where the gear ratio at which mode switching is started is further increased from the design value (with earlier switching). The diagram which shows the 1st example of the experimental result of a real vehicle corresponding to a present Example. The diagram which similarly shows the 2nd example. The diagram which shows the experimental result of the real vehicle corresponding to FIG. The diagram which shows the experimental result of the real vehicle corresponding to FIG. The block diagram of the conventional continuously variable transmission. The hydraulic circuit diagram which shows the hydraulic mechanism integrated in this continuously variable transmission. The diagram which shows the state from which the gear ratio of a toroidal type continuously variable transmission fluctuates with the fluctuation | variation of passage torque. The diagram which shows the relationship between the speed ratio as the whole continuously variable transmission, the direction and magnitude | size of the torque which passes a toroidal type continuously variable transmission, and the gear ratio of this 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 Line pressure control electromagnetic on-off valve 19 Solenoid valve 20 Shifting solenoid valve 21 Control valve device 22 Gear ratio control valve 23 Differential pressure cylinders 24a, 24b Correction control valve 25 High speed clutch Switching valve 26 Low speed clutch switching valve 27, 27a, 27b Oil pump 28 Oil reservoir 29a, 29b Pressure regulating valve 30 Manual hydraulic switching valve 31 Low speed clutch electromagnetic switching valve 32 High speed clutch electromagnetic switching valve 33a, 33b Hydraulic chamber

Claims (5)

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 the controller controls the engagement / disengagement of each of these clutches so that the speed change state is set to one of the low speed mode and the high speed mode. in a combination, the mode switching between the above-mentioned low-speed mode and the high-speed mode, connected to it in one of the clutch of the above low speed clutch and the high speed clutch Is Connect the clutch was not, also by cutting off the connection of the clutch, which is connected to it with the other clutch, and sets the time for the both clutches are simultaneously connected, the toroidal type continuously variable Changes in the speed ratio of the entire continuously variable transmission as a result of torque shift , which is a change in the gear ratio of the toroidal type continuously variable transmission based on fluctuations in the magnitude and direction of torque passing through the transmission, The direction in which the speed ratio of the entire continuously variable transmission changes based on the torque shift and the mode switching in order to reduce or eliminate the uncomfortable feeling associated with the mode switching in accordance with the running state of the vehicle. The speed ratio value of the toroidal-type continuously variable transmission that starts this mode switching is set to this mode switching in order to match the direction in which this speed ratio is changed accordingly. Continuously variable transmission from the target gear ratio is a value of the design should be performed, characterized in that shifting depending on the running state of the vehicle at that point. The continuously variable transmission according to claim 1 , wherein a value of a gear ratio of the toroidal type continuously variable transmission for starting mode switching is shifted to a speed increasing side with respect to a target gear ratio. Any deviation from the target gear ratio depending on the magnitude of the passing torque, the magnitude of the input torque from the engine, and the vehicle speed, which is a state quantity that affects the amount of change in the gear ratio of the toroidal-type continuously variable transmission. The continuously variable transmission according to any one of claims 1 to 2 , wherein the amount is adjusted. By changing the timing of outputting a signal indicating that mode switching should be started for each clutch for low speed and high speed, the value of the gear ratio of the toroidal type continuously variable transmission that starts mode switching is shifted from the target gear ratio. The continuously variable transmission as described in any one of Claims 1-3 . By changing the timing for outputting the signal indicating to start a connection to one of the clutch, shifting the value of the transmission ratio of the toroidal type continuously variable transmission to start mode switching from the target gear ratio, according to claim 4 Continuously variable transmission.

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