JP2007100553A - Continuously variable transmission - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent a shift shock even if a state of not simultaneously engaging both low speed and high speed clutches appears when switching a mode. <P>SOLUTION: An engine speed of an engine is adjusted independently of accelerator operation of a driver on condition of starting switching of the mode. The engine speed is smoothly returned in response to the accelerator operation of the driver on condition of finishing the switching of the mode. As a result, the problem can be solved by preventing a sudden increase in the engine speed in a state of disengaging both clutches. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an improvement of a continuously variable transmission incorporating a toroidal type continuously variable transmission, for example, used as an automatic transmission for a vehicle (automobile), and has a structure capable of smoothly switching between a low speed mode and a high speed mode. 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. 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 8. It has been. Among these, Patent Documents 3 to 4 describe 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. A continuously variable transmission having a mode (high speed mode) for realizing a so-called power split state in which a gear ratio is adjusted by a continuously variable transmission is described. Further, in Patent Documents 5 to 8 described above, a mode capable of realizing a 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. A continuously variable transmission with (low speed mode) is described.

  FIGS. 10-11 has shown the continuously variable transmission provided with the mode which can implement | achieve the geared neutral state described in patent documents 7-8. Of these, FIG. 10 shows a block diagram of a continuously variable transmission, and FIG. 11 shows a hydraulic circuit that controls the continuously variable transmission. The output of the engine 1 is input to the input shaft 3 via the damper 2. The power transmitted to the input shaft 3 is transmitted to the planetary gear type transmission 5 which is a differential unit, either directly or via the toroidal continuously variable transmission 4. The differential components of the constituent members of the planetary gear type transmission 5 are taken out to the output shaft 9 via the clutch device 6, that is, the low speed and high speed clutches 7 and 8 shown in FIG.

  The toroidal continuously variable transmission 4 includes input and output disks 10 and 11, a plurality of power rollers 12, a plurality of trunnions (not shown), an actuator 13 (FIG. 11), A pressing device 14 and a gear 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. 11). 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. 11) 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. 11) 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. Further, the supply / discharge state of the pressure oil to the low speed and high speed clutches 7 and 8 is switched according to the switching of the shift solenoid valve 20.

  When the continuously variable transmission shown in FIGS. 10 to 11 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. 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 Documents 3 to 4, smooth switching of the mode when switching between the low speed mode and the high speed mode can improve the riding comfort performance. It is important in terms of ensuring (good ride) and durability. As a technique for smoothly performing such mode switching, for example, Patent Document 9 describes a technique for simultaneously connecting a clutch that has not been connected and a clutch that has been connected so far when the mode is switched. Has been.

  If such a technique is adopted, for example, when switching from the low speed mode to the high speed mode during acceleration, as shown in FIG. 12 (A), the high speed clutch that has not been connected until then is connected. The connection of the low-speed clutch that was connected until is disconnected. For this reason, when the mode is switched, both the low speed clutch and the high speed clutch are disconnected at the same time, so that the engine rotational speed suddenly rises (blows up) and the shift shock accompanying the connection of the high speed clutch after this sudden rise ( Torque sensation and push-out feeling) can be prevented, and the driver and other passengers can be prevented from feeling uncomfortable. Further, it is possible to reduce the impact applied to the constituent parts at the time of mode switching, and to ensure durability. Further, Patent Document 10 discloses a continuously variable transmission capable of realizing a power split state, in which a low speed clutch for switching from a low speed mode to a high speed mode is compared with a timing for disconnecting the high speed clutch for switching from a high speed mode to a low speed mode. There is described an invention that secures a time during which both clutches are connected at the time of mode switching by lengthening the timing of cutting off. 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.

  By the way, in the case of the prior art disclosed in the above-mentioned patent documents and the prior invention disclosed in Japanese Patent Application No. 2004-185277, it is determined whether or not the low speed and high speed clutches are simultaneously connected at the time of mode switching. It is not done. On the other hand, at the time of mode switching, these low speed and high speed clutches are connected in accordance with the state at the time of switching, for example, the oil temperature and the temperature characteristics of the friction material constituting the low speed and high speed clutches. The time from connection to disconnection (to be able to transmit power) is different. For this reason, at the time of mode switching as described above, after connecting the high-speed clutch that was not connected until then, the hydraulic oil to these clutches is disconnected so that the connection of the low-speed clutch that was previously connected is disconnected. Even if the switching states of the low-speed clutch switching valve and the high-speed clutch switching valve for switching the supply / discharge state are switched, there is a possibility that the two clutches may not be connected at the same time depending on the oil temperature or the like.

  That is, when the oil temperature is low and the viscosity of the oil is high, resistance against the flow of pressure oil in the oil passage increases, so that the low speed and high speed clutches are connected when the mode is switched. It takes longer to start connecting after starting. In such a case, as shown in FIG. 12 (B), before the clutch that was not connected so far is completely connected, there is a possibility that the clutch that has been connected so far is disconnected. In such a case, both the low speed clutch and the high speed clutch are disconnected at the same time, and as described above, the engine rotational speed suddenly rises (blows up), and the speed change associated with the clutch connection after the sudden rise There is a possibility that a shock may be generated and the driver and other passengers may feel uncomfortable.

  In order to prevent such inconvenience, it is conceivable to disconnect the clutch to be disconnected after determining whether or not the low speed clutch and the high speed clutch are simultaneously connected. For example, it is determined whether or not the clutch to be connected has been connected by detecting the hydraulic pressure introduced to each of these clutches or by detecting the displacement of the pistons or the like constituting each of these clutches. Can be considered. However, in such a case, it is necessary to separately provide a hydraulic sensor or a hydraulic switch for detecting the hydraulic pressure, or a displacement sensor (stroke sensor) for detecting the displacement of the piston or the like. And the cost may increase.

  On the other hand, without determining whether or not the clutch to be connected as described above is connected, the timing of connection and disconnection of each clutch is adjusted according to the state of the vehicle such as the oil temperature at the time of mode switching. It is also possible to do. For example, by providing an oil temperature sensor for detecting the oil temperature and changing the connection / disconnection timing of each clutch according to the detected oil temperature, both the low speed and high speed clutches can be used regardless of the oil temperature. It is conceivable to create time to connect simultaneously. However, when such a structure is adopted, a correlation between the oil temperature and the optimum connection / disconnection timing corresponding to the oil temperature is obtained in advance, and this correlation is mapped to a memory or a formula in the controller. It is necessary to memorize as etc. Since the clutches are engaged / disengaged based on such correlation, the engagement / disengagement control of these clutches may be complicated.

  Patent Documents 11 and 12 also describe a technique for smooth mode switching (a technique for reducing a shift shock during mode switching). Of these, Patent Document 11 describes a technique for preventing a shift shock regardless of the difference between the gear ratio at which the mode should be switched and the actual gear ratio. That is, in Patent Document 11, when the mode is switched, a shift in the speed ratio is detected from the speed ratio of the entire continuously variable transmission and the rotational speed of the input shaft, and the engine torque is increased or decreased according to the shift (target). Techniques for limiting engine torque) are described. However, in the case of the technique described in Patent Document 11 as described above, the engine torque is only controlled according to the shift in the gear ratio at the start of mode switching, and the clutch is connected or disconnected at the time of mode switching. Accordingly, the engine torque cannot be controlled. For this reason, when both the low speed clutch and the high speed clutch are disconnected at the same time as described above, it is not possible to reduce the shift shock accompanying the sudden increase in the engine speed.

  Patent Document 12 describes a technique for controlling the engine torque to a target engine torque calculated from the gear ratio of the toroidal type continuously variable transmission. In the case of the technique described in Patent Document 12, when the rotational speed of the engine suddenly increases at the time of mode switching, the gear ratio of the toroidal continuously variable transmission that is actually detected is corrected, and the corrected shift is performed. The target engine torque corresponding to the ratio is controlled. If such a technique is adopted, even if the engine speed increases rapidly, it is considered that the engine torque can be prevented from excessively decreasing and the shift shock can be reduced. However, in the case of such a conventional technique, at the time of mode switching, the gear ratio of the toroidal continuously variable transmission is detected, the gear ratio is corrected, and the target engine torque is calculated based on the corrected gear ratio. Further, many operations such as controlling the engine torque to the target engine torque are required, and it is inevitable that the control of the engine torque becomes complicated.

Japanese Patent No. 2734583 JP-A-5-39850 Japanese Patent Laid-Open No. 10-196759 JP 2003-194207 A JP 2003-307266 A JP 2000-220719 A JP 2004-225888 A JP 2004-211836 A Japanese Patent Laid-Open No. 9-210191 JP 2003-207042 A JP 2002-264698 A JP 2002-362193 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 has a complicated structure capable of preventing a shift shock due to a sudden increase in the rotational speed of the engine even when both the low speed clutch and the high speed clutch are not connected at the time of mode switching. It was invented to be realized at a low cost without requiring a mechanism, a device, or the like.

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 / disengagement of the clutches to change the shift state to either the low speed mode or the high speed mode.
And, when the mode is switched between the low speed mode and the high speed mode, a clutch that has not been connected by one of the low speed clutch and the high speed clutch is connected to the controller. Similarly, by providing a function of disconnecting the clutch that was previously connected by the other clutch, the time during which both clutches are simultaneously connected is set.
In particular, in the continuously variable transmission according to the present invention, the controller has a function of adjusting the engine speed independently of the driver's accelerator operation on the condition that the mode switching is started. Give it. At the same time, on the condition that the mode switching has been completed, a function of returning (smoothly and gradually) the rotational speed of the engine to that corresponding to the driver's accelerator operation is provided.

  It should be noted that the start of the mode switching can be made at the time when the connection of one clutch that has not been connected is started. Further, after starting the connection of the one clutch, it may be the time when the connection of the other clutch which has been connected is started to be disconnected. The reason for this is that when the clutch is disconnected at the time of mode switching and then the other clutch is disconnected, there is a possibility that both clutches may be disconnected at the same time. This is because it is after starting to disconnect the clutch. In any case, the start of connection of the one clutch (or the start of disconnection of the other clutch) is performed, for example, on an electromagnetic switching valve for switching the connection state of the one clutch (or the other clutch). It can be the time when a command signal for starting connection (or disconnecting) is output from the controller.

  On the other hand, the completion of the mode switching can be made when the connection of the one clutch is completed. Completion of the connection of one of these clutches is more specifically the change of torque (power, transmission torque, passing torque) passing through the toroidal continuously variable transmission, and more specifically, passing through this toroidal continuously variable transmission. The determination can be made based on the pressure difference between the pair of hydraulic chambers constituting the actuator having a correlation with the torque to be generated. That is, the support members (trunnions) that rotatably support the power rollers are displaced in the axial directions of the pivots provided at both ends thereof, to change the gear ratio of the toroidal continuously variable transmission. A pressure difference (differential pressure) between a pair of hydraulic chambers provided in the actuator is detected by, for example, a hydraulic sensor, and can be determined from a change in the pressure difference. For example, it can be determined that the engagement of the one clutch has been completed by detecting that the sign of the pressure difference has been reversed beyond 0 (and has changed across a preset threshold).

  As described above, in the continuously variable transmission according to the present invention, when mode switching is started, the rotational speed of the engine is adjusted independently of the driver's accelerator operation. For this reason, even when both the low speed clutch and the high speed clutch are disconnected at the time of mode switching, it is possible to prevent the engine speed from rapidly increasing. That is, when the rotational speed of the engine is adjusted in accordance with the driver's accelerator operation, for example, when both the low speed and high speed clutches are disconnected at the same time as the oil temperature is low, If the torque applied to the engine is released (torque is lost) and no special control is performed on the engine, the rotational speed of the engine increases rapidly. Thus, a shift shock is generated at the moment when one of the clutches is connected, because the engine speed increases rapidly.

  On the other hand, in the case of the present invention, the rotation speed of the engine is adjusted independently of the driver's accelerator operation so that the rotation speed does not increase rapidly (for example, the rotation speed is kept constant) , Increase or decrease at a predetermined speed). For this reason, even when both the low speed clutch and the high speed clutch are disconnected at the time of mode switching, the engine speed does not increase rapidly. In addition, after the mode switching is completed, the engine speed can be returned to the speed according to the driver's accelerator operation smoothly (for example, gradually), so that the driving intended by the driver can be restored without feeling uncomfortable. it can. Moreover, in order to adjust the rotational speed of the engine independently of the driver's accelerator operation, and to smoothly (gradually) return the rotational speed to that corresponding to the driver's accelerator operation, a complicated configuration is required. Does not require any mechanism or device. For this reason, the structure which can prevent the shift shock accompanying the rapid increase of the rotational speed of the engine at the time of mode switching can be configured at low cost.

Preferably, when the present invention is implemented, the engine rotational speed is maintained at the value at the time when the connection of one clutch is started on the condition that the connection of one clutch is started. 2). Alternatively, the degree of change in the rotational speed of the engine is maintained at the change speed immediately before the connection of the one clutch is started (Claim 3). Then, on the condition that the connection of the one clutch is completed, the rotational speed of the engine is returned to that corresponding to the driver's accelerator operation. In this case, preferably, as described in claim 4, on the condition that the connection of the one clutch is completed, a target engine speed is obtained based on the accelerator opening and the vehicle speed at that time, By adjusting the target rotational speed (for example, gradually), the rotational speed of the engine is returned (smoothly) to a value corresponding to the driver's accelerator operation.
With this configuration, even when both the low speed clutch and the high speed clutch are disconnected at the time of mode switching, the engine speed does not increase rapidly. In addition, at the end of the mode switching, the driving intended by the driver can be smoothly returned without giving a sense of incongruity. In addition, since a complicated configuration, mechanism, device, or the like is not required for adjusting the rotational speed of the engine as described above, it can be configured at low cost.

Further, when implementing the present invention, preferably, as described in claim 5, when switching from the low speed mode to the high speed mode, the accelerator opening is set on the condition that the connection of the high speed clutch is started, A predetermined value is decreased from the value at the time when the connection of the high speed clutch is started, and the engine speed is maintained at the accelerator opening. At the same time, on the condition that the connection of the high speed clutch is completed, the accelerator opening is returned (for example, gradually) to the actual accelerator opening corresponding to the accelerator operation of the driver at that time. Furthermore, as described in claim 6, when switching from the high speed mode to the low speed mode, the accelerator opening degree is started and the connection of the low speed clutch is started on the condition that the connection of the low speed clutch is started. A predetermined value is increased from the value at that time, and the engine speed is maintained at the accelerator opening. At the same time, on the condition that the connection of the low speed clutch is completed, the accelerator opening is returned (for example, gradually) to the actual accelerator opening corresponding to the accelerator operation of the driver at that time. Also in this configuration, it is possible to prevent a rapid increase in the engine speed at the time of mode switching, and to smoothly return without causing a sense of incongruity to the driving intended by the driver at the time of mode switching end. In addition, since a complicated configuration, mechanism, device, or the like is not required for adjusting the accelerator opening as described above, it can be configured at low cost.

Further, when implementing the present invention, preferably, as described in claim 7, 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 is provided. .
In the case of such a continuously variable transmission having a mode capable of realizing the geared neutral state, the mode switching between the low speed mode and the high speed mode is performed at a low speed. For this reason, this mode switching is frequently performed every time the vehicle starts and stops, and it is highly necessary to perform mode switching smoothly, so that the effects of the present invention can be obtained remarkably.

  1 to 4 show a first embodiment of the present invention corresponding to claims 1, 2, 4, and 7. The feature of this embodiment is that the speed of the engine 1 is prevented from rapidly increasing even when the low speed and high speed clutches 7 and 8 as the clutch device 6 are disconnected at the time of mode switching. Thus, it is possible to prevent the occurrence of a shift shock that causes the driver to feel uncomfortable or impairs the durability of the component parts. Since the structure and operation of the other parts are the same as those of the conventional structure shown in FIGS. 10 to 11 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. In a state (OFF), 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 electromagnetic switching valves 31 and 32 for the low speed clutch and the high speed clutch are energized ( 2), 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.

  In the case of the present embodiment, the controller 16 has not been connected to one of the low-speed clutch 7 and the high-speed clutch 8 until the mode switching between the low-speed mode and the high-speed mode. After the clutch 7 (8) is connected, the clutch 8 (7) that has been connected by the other clutch is disconnected. That is, when the mode is switched from the low speed mode to the high speed mode, the high speed clutch 8 is connected (the high speed clutch electromagnetic switching valve 32 is turned on), and then the low speed clutch 7 is disconnected (for the low speed clutch). In the case of switching the mode from the high speed mode to the low speed mode, the low speed clutch 7 is connected (the low speed clutch electromagnetic switching valve 31 is OFF) and then the high speed mode is switched. The clutch 8 is disconnected (the high-speed clutch electromagnetic switching valve 32 is turned off).

  Further, in the case of the present embodiment, the controller 16 is provided with a function of adjusting the rotational speed of the engine 1 independently of the driver's accelerator operation on the condition that mode switching is started. More specifically, the rotation of the engine 1 is performed on the condition that one of the low-speed clutch 7 and the high-speed clutch 8 that has not been connected is started. The speed is maintained at the value at the time when the connection of the one clutch 7 (8) is started. Along with this, a function of returning the rotational speed of the engine 1 to that corresponding to the driver's accelerator operation is provided on condition that the mode switching is completed. More specifically, on the condition that the connection of the one clutch 7 (8) is completed, the target rotational speed of the engine 1 is obtained based on the accelerator opening and the vehicle speed at that time, and this target rotational speed is obtained. To adjust smoothly (gradually).

Such functions of the controller 16 will be described with reference to the flowchart of FIG. The work shown in this flowchart is more preferably performed while the forward travel state (D, L range) is selected by the manual hydraulic pressure switching valve 30 from when the ignition switch is turned on to when it is turned off. The operation is repeated (automatically) while the gear ratio of the toroidal-type continuously variable transmission 4 is operating in the vicinity of a value for mode switching {for example, the maximum reduction gear ratio (the gear ratio is the minimum value)}.
First, in step 1, the controller 16 determines whether or not a condition for mode switching is satisfied. In this determination, for example, whether or not the speed ratio of the toroidal type continuously variable transmission 4 is a predetermined value (for example, maximum reduction ratio = 0.46) is detected by the input side and output side both rotation sensors 35 and 36. The determination is made on the basis of the ratio of the rotational speeds of the input and output disks 10 and 11 or on the basis of the correlation between the step position of the stepping motor 17 and the gear ratio determined in advance. If it is determined in step 1 that the transmission ratio of the toroidal type continuously variable transmission 4 is not a predetermined value, the mode switching is terminated without returning to the start (return to the start).

  On the other hand, if it is determined in step 1 that the gear ratio of the toroidal-type continuously variable transmission 4 is a predetermined value and the condition for mode switching is satisfied, as shown in the following step 2 Then, it is determined whether or not the current travel mode is the low speed mode. This determination is performed based on the control signal output from the controller 16 to the low-speed clutch and high-speed clutch electromagnetic switching valves 31 and 32 immediately before this determination. If the control signal output immediately before by the controller 16 in step 2 is such that the low speed mode is realized (the low speed clutch 7 is connected and the high speed clutch 8 is disconnected), Is determined to be the low speed mode. If it is determined that the current travel mode is the low speed mode, the high speed clutch electromagnetic switching valve 32 is switched (the energized state is turned ON) to connect the high speed clutch 8 in step 3. To do). If the high-speed clutch electromagnetic switching valve 32 is switched in step 3 as described above, the rotational speed of the engine 1 is changed to the time when the switching of the high-speed clutch electromagnetic switching valve 32 is started (step 4). The value of the energized state is maintained as it was).

  Then, with the rotational speed of the engine 1 maintained at a constant value in this way, the process proceeds to the subsequent step 5 to determine whether or not a predetermined time has elapsed since the switching of the high-speed clutch electromagnetic switching valve 32 was started. judge. This predetermined time is the time from the start of connection of the high speed clutch 8 to the start of disconnection of the low speed clutch 7. Such a predetermined time is obtained and set in advance by experiments or the like so as to secure a time during which the low speed and high speed clutches 7 and 8 are simultaneously connected when the mode is switched. By switching the predetermined time according to the temperature of the oil (lubricating oil, traction oil) introduced into the low speed and high speed clutches 7 and 8, the mode can be switched regardless of the oil temperature. Sometimes it is possible to reliably create a time for simultaneously connecting the low speed and high speed clutches 7 and 8 at the same time. Specifically, it is conceivable that the predetermined time is lengthened as the oil temperature is lower. However, as will be described later, in the structure of this embodiment, the predetermined time is shortened so that the speed change operation can be performed quickly, and as a result, the low speed and high speed clutches 7 and 8 are disconnected at the same time. Even when appears, it is possible to prevent the rotational speed of the engine 1 from rapidly increasing. For this reason, in this embodiment, the predetermined time is not adjusted according to the oil temperature of the oil (the predetermined time may be adjusted according to the oil temperature as necessary).

  If it is determined in step 5 that the predetermined time has not elapsed, the process returns to step 4 to maintain the engine 1 at a constant rotational speed and continue this operation until the predetermined time has elapsed. repeat. If it is determined in step 5 that the predetermined time has elapsed, the process proceeds to step 6 where the low-speed clutch electromagnetic switching valve 31 is switched to disconnect the low-speed clutch 7 (the energization state is turned ON). To do). Next, the process proceeds to step 7 where it is determined whether or not the connection of the high speed clutch 8 has been completed. This determination is made based on a differential pressure between the hydraulic chambers 33a and 33b of the actuator 13, which represents a change in torque passing through the toroidal type continuously variable transmission 4.

  That is, when the high speed clutch 8 is connected, torque (power, transmission torque, passing torque) passing through the toroidal-type continuously variable transmission 4 from the state where the low speed clutch 7 is connected is obtained. Invert. The differential pressure having a correlation with the torque also exceeds 0 from the previous value, and the sign is reversed. For this reason, if such a change in the differential pressure is detected by a pair of hydraulic sensors 34a, 34b (34 in FIG. 1) provided in the respective hydraulic chambers 33a, 33b, the above-described change in the differential pressure causes the above-described difference in pressure. It can be determined that the high-speed clutch 8 is connected. If it is determined in step 7 that the connection of the high speed clutch 8 is completed, the process proceeds to step 13 to be described later. Thus, until it progresses to step 13, the rotational speed of the said engine 1 is kept constant.

  On the other hand, if the control signal output immediately before by the controller 16 in the step 2 is to achieve the high speed mode (disconnect the low speed clutch 7 and connect the high speed clutch 8), It is determined that the traveling mode is the high speed mode. When it is determined that the current travel mode is the high speed mode, the low speed clutch electromagnetic switching valve 31 is switched to connect the low speed clutch 7 in step 8 (the energized state is turned OFF). ). If the low-speed clutch electromagnetic switching valve 32 is switched in step 8 as described above, as shown in the following step 9, the rotational speed of the engine 1 is changed to the time when switching of the low-speed clutch electromagnetic switching valve 31 is started (energization). The value at the time when the state is turned off is maintained.

  Then, in a state where the rotational speed of the engine 1 is maintained at a constant value, the process proceeds to the subsequent step 10 to determine whether or not a predetermined time has elapsed since the switching of the high-speed clutch electromagnetic switching valve 32 was started. judge. This predetermined time is the time from the start of connection of the low speed clutch 7 to the start of disconnection of the high speed clutch 8. Such a predetermined time is obtained and set in advance by experiments or the like so as to secure a time during which the low speed and high speed clutches 7 and 8 are simultaneously connected when the mode is switched. Such step 10 is the same as step 5 described above except that the clutch to be connected is the low speed clutch 7 and the clutch to be disconnected is the high speed clutch 8. If it is determined in step 10 that the predetermined time has elapsed, the process proceeds to the next step 11 where the high-speed clutch electromagnetic switching valve 32 is switched to turn off the high-speed clutch 8 (turn off the energized state). ). Next, the routine proceeds to step 12 where it is determined whether or not the connection of the low speed clutch 7 has been completed. Step 12 is the same as Step 7 described above except that the clutch to be connected is the low speed clutch 7 and the clutch to be disconnected is the high speed clutch 8.

  If it is determined in step 12 that the connection of the low speed clutch 7 is completed, or if it is determined in step 7 that the connection of the high speed clutch 8 is completed, the following step 13 is performed. Thus, based on the accelerator opening at that time and the vehicle speed (vehicle speed), an appropriate engine target rotational speed is obtained, and the target rotational speed is smoothly (eg gradually) adjusted. The accelerator opening is detected by an accelerator sensor 37 for detecting, for example, an accelerator pedal operation amount (depression amount, release amount). The vehicle speed is detected by the output shaft rotation sensor 38 for detecting the rotation speed of the output shaft 9 or a vehicle speed sensor provided separately. Based on the vehicle speed and the accelerator opening detected by such sensors 37 and 38, the target rotational speed is obtained, and the accelerator opening is adjusted to achieve the target rotational speed.

  If the accelerator opening is adjusted in this way, it is determined in subsequent step 14 whether or not the actual rotational speed has reached the target rotational speed (matched the target rotational speed). If it is determined in step 14 that the actual rotational speed does not match the target rotational speed, the process returns to step 13 and is repeated until the target rotational speed is reached (matched). If it is determined in step 14 that the actual rotational speed has reached the target rotational speed, the present control is terminated, and normal engine control, that is, engine control corresponding to the driver's accelerator operation is performed. Return to.

  As described above, according to the present embodiment, when mode switching is started, the rotational speed of the engine 1 is adjusted independently of the driver's accelerator operation. Specifically, the rotational speed of the engine 1 is determined on the condition that one of the low-speed clutch 7 and the high-speed clutch 8 that has not been connected is started. Is maintained at the value at the time when the connection of the one clutch 7 (8) is started. For this reason, even when the low speed and high speed clutches 7 and 8 are simultaneously disconnected at the time of mode switching, it is possible to prevent the rotational speed of the engine 1 from rapidly increasing. That is, as shown in FIG. 4B, when the mode is changed, the rotational speed of the engine 1 is adjusted according to the driver's accelerator operation. When the high-speed clutches 7 and 8 are disconnected at the same time, the torque applied to the engine 1 is released (torque is released), and the rotational speed of the engine 1 increases rapidly. Thus, a shift shock is generated at the moment when one of the clutches (the high speed clutch 8) is connected by the amount that the rotational speed of the engine rapidly increases.

  On the other hand, in the case of the present embodiment, as shown in FIG. 5A, even when the low speed and high speed clutches 7 and 8 are disconnected at the time of mode switching, the engine 1 rotates. The speed does not increase rapidly. In addition, after the mode switching is completed (after the connection of the high speed clutch in FIG. 4 is completed), the rotational speed of the engine 1 is gradually returned to that corresponding to the driver's accelerator operation (to the target engine rotational speed). Because it adjusts gradually), it can return smoothly without giving the driver a sense of incongruity. Moreover, in order to maintain the rotational speed of the engine 1 at a constant level or to gradually return the rotational speed to that corresponding to the driver's accelerator operation, a complicated configuration, mechanism, device, or the like is not required. . For this reason, the structure which can prevent the shift shock accompanying the rapid increase of the rotational speed of the engine at the time of mode switching can be configured at low cost.

  In the case of the present 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, 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 and high speed clutches are controlled by the low speed clutch and high speed clutch electromagnetic switching valves 31 and 32, respectively. In addition to controlling the hydraulic pressure sent to the hydraulic chambers 7 and 8, it can also be controlled by an electromagnetic proportional valve or an actuator such as a motor. The connection / disconnection of the low speed and high speed clutches 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. As described above, in the case of this embodiment, when the low speed mode is realized, both the low speed clutch and high speed clutch electromagnetic switching valves 31 and 32 are deenergized and the high speed mode is realized. Both the electromagnetic switching valves 31 and 32 are energized. For this reason, even when the electromagnetic switching valves 31 and 32 cannot be energized due to some failure, traveling in the low-speed mode can be secured, and a fail-safe operation (improvement of safety performance at the time of failure) can be achieved.

  5 and 6 show a second embodiment of the present invention corresponding to claims 1, 3 and 4. In the case of the first embodiment described above, it is a condition that the connection of one clutch 7 (8), which has not been connected so far, between the low speed clutch 7 and the high speed clutch 8 (see FIG. 2) is started. In addition, the rotational speed of the engine 1 (see FIG. 1) is maintained at the value at the time when the connection of the one clutch 7 (8) is started. On the other hand, in the case of this embodiment, on the condition that the connection of one clutch 7 (8) is started, the speed at which the rotation speed of the engine 1 changes is set to the one clutch 7 (8). The rate of change immediately before the connection is started is maintained. For this reason, in the case of this embodiment, the speed at which the rotational speed of the engine 1 changes in step 4 and step 9 in the flowchart is the time when switching of the high-speed clutch electromagnetic switching valve 32 is started (the energization state is turned on). Or at the time immediately before the switching of the low-speed clutch electromagnetic switching valve 31 (see FIGS. 1 and 2) is started (at the time when the energized state is turned off).

Also in this embodiment, as shown in FIG. 6, even when both the low speed and high speed clutches 7 and 8 are disconnected at the time of mode switching, the rotational speed of the engine 1 does not increase rapidly. . Further, after the mode switching is completed, that is, after the connection of the high speed clutch in FIG. 6 is completed, the rotational speed of the engine 1 is smoothly returned to the one corresponding to the driver's accelerator operation (the target engine rotational speed). Therefore, it is possible to return without giving a sense of incongruity to the driving intended by the driver.
Other configurations and operations are the same as those of the first embodiment described above, and thus redundant description is omitted.

  7 and 8 show a third embodiment of the present invention corresponding to claims 1, 4, 5 and 6. In the case of the above-described second embodiment, it is a condition that the connection of one of the low-speed clutch 7 and the high-speed clutch 8 (see FIG. 2), which has not been connected so far, is started. Furthermore, the speed at which the rotational speed of the engine 1 (see FIG. 1) changes is maintained at the changing speed immediately before the connection of the one clutch 7 (8) is started. On the other hand, in the case of this embodiment, when switching from the low speed mode to the high speed mode, the accelerator opening is set to the high speed on the condition that the connection of the high speed clutch 8 which is the one clutch is started. A predetermined value is decreased from the value at the time when the connection of the clutch 8 is started, and the rotational speed of the engine 1 is maintained at the accelerator opening. That is, in step 4 of the flowchart, the accelerator opening is lowered by a predetermined value α (see the actual accelerator opening diagram in FIG. 8) from the value at that time.

  Such a predetermined value α is set (tuned) in a range that does not give the driver a sense of incongruity even when the accelerator opening is reduced at the time of mode switching, and is obtained in advance by experiments or the like. On the other hand, when switching from the high-speed mode to the low-speed mode, on the condition that the connection of the low-speed clutch 7 which is one of the clutches is started, the accelerator opening degree is connected and the connection of the low-speed clutch 7 is started. A predetermined value is increased from the value at the time, and the rotational speed of the engine 1 is maintained at the accelerator opening. That is, in step 9 of the flowchart, the accelerator opening is increased by a predetermined value α from the value at that time. Such a predetermined value α is also set (tuned) in a range that does not give the driver a sense of incongruity even when the accelerator opening is increased at the time of mode switching, and is obtained in advance by experiments or the like.

In the case of this embodiment, when it is determined in step 7 that the connection of the high speed clutch 8 is completed, or in step 12, it is determined that the connection of the low speed clutch 7 is completed, In the following step 13, the accelerator opening is gradually returned to the actual accelerator opening corresponding to the accelerator operation of the driver at that time (see the actual accelerator opening diagram in FIG. 8). Then, by gradually returning to the actual accelerator opening in this way, it is possible to return smoothly without giving a sense of incongruity to the driving intended by the driver.
Other configurations and operations are the same as those of the first and second embodiments described above, and a duplicate description is omitted.

  In each of the above-described embodiments and the above-described embodiments, the fuel injection amount of the engine 1 (see FIG. 1) is adjusted independently of the driver's accelerator operation (actual accelerator opening) on the condition that mode switching starts. (Controlled). In the case of the above-described first and second embodiments, as shown in FIG. 9A, from the transmission controller 39 (= controller 16) for controlling the continuously variable transmission on condition that mode switching is started. The engine controller (engine controller) 40 for controlling the engine 1 receives a signal (Example 1) for maintaining the rotational speed of the engine 1 constant, or the speed of change of the rotational speed of the engine 1 A signal (Example 2) is output to maintain the value constant. The engine controller 40 adjusts (controls) the fuel injection amount of the engine 1 based on such a signal, maintains the rotation speed of the engine 1 constant, or maintains the change speed of the rotation speed constant. To maintain. In this state, the actual accelerator opening signal output from the accelerator sensor 37 based on the driver's accelerator operation is ignored. Then, on the condition that the mode switching is completed, the rotational speed of the engine 1 is returned to that corresponding to the driver's accelerator operation. Therefore, the diagram of the actual accelerator opening shown in FIG. 4A of the first embodiment and the diagram of the actual accelerator opening shown in FIG. 6 of the second embodiment are represented in the same way. (The diagram representing the accelerator opening based on the driver's accelerator operation is the same in the first and second embodiments), but the engine controller 40 determines the fuel injection amount of the engine 1 as described above. In order to adjust (control) according to the signal output from the transmission controller 39, the change in the rotational speed of the engine 1 is different.

  In the case of the third embodiment described above, as shown in FIG. 9B, the signal of the actual accelerator opening output from the accelerator sensor 37 is transmitted to the engine controller 40 via the transmission controller 39. Sent to. During normal driving, an actual accelerator opening signal corresponding to the driver's accelerator operation is sent to the engine controller 40 as it is. On the other hand, at the time of mode switching, on the condition that the mode switching is started, the actual accelerator opening signal output from the transmission controller 39 is different from the signal corresponding to the driver's accelerator operation. That is, as shown in the diagram of the actual accelerator opening in FIG. 8 of the third embodiment, the signal corresponding to the driver's accelerator operation corresponds to the broken line on the condition that the mode switching is started. The actual accelerator opening signal output from the transmission controller 39 corresponds to the solid line. The fuel injection amount of the engine 1 is adjusted according to the signal (signal corresponding to the solid line) output from the transmission controller 39 in this way, and the rotational speed of the engine 1 is represented in the same figure. Become something. Although the actual engine speed diagram in FIG. 8 and the actual engine speed diagram in FIG. 4A are represented in the same manner, the actual accelerator opening curve is shown in FIG. The difference is that the fuel injection amount of the engine 1 is adjusted in accordance with the actual accelerator opening signal output from the transmission controller 39 in the third embodiment as described above. is there.

  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. . Further, it can be used not only as an automatic transmission for automobiles but also as a transmission for various industrial machinery. 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 incorporated in this continuously variable transmission. 5 is a flowchart illustrating an operation that is a feature of the first embodiment. A diagram showing the relationship between the oil pressure of each clutch for low speed and high speed, the actual accelerator opening, and the actual engine speed when switching from the low speed mode to the high speed mode during acceleration (with the accelerator pedal depressed) (A) shows the case where the control of this embodiment is performed, and (B) shows the case of the conventional control. The figure similar to FIG. 3 which shows Example 2 of this invention. A diagram similar to (A) in FIG. 4 showing the relationship between the hydraulic pressure of each clutch for low speed and high speed, the actual accelerator opening, and the actual engine speed when switching from the low speed mode to the high speed mode during acceleration. . The figure similar to FIG. 3 which shows Example 3 of this invention. A diagram similar to (A) in FIG. 4 showing the relationship between the hydraulic pressure of each clutch for low speed and high speed, the actual accelerator opening, and the actual engine speed when switching from the low speed mode to the high speed mode during acceleration. . It is a figure for demonstrating the state in which control of an engine is performed independently of a driver | operator's accelerator operation, (A) is a figure corresponding to Example 1, 2, (B) is a figure corresponding to Example 3. FIG. Respectively. The block diagram of the conventional continuously variable transmission. The hydraulic circuit diagram incorporated in this continuously variable transmission. The diagram which shows two examples of the relationship of the connection state of each clutch for low speed and high speed, and the switching state of each switching valve for low speed and high speed.

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 34, 34a, 34b Hydraulic sensor 3 Input rotary sensor 36 output side rotation sensor 37 accelerator sensor 38 output shaft rotation sensor 39 transmission control unit 40 engine control unit

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 The controller is configured to change the shift state to one of the low speed mode and the high speed mode by controlling connection and disconnection of each clutch. 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. A continuously variable transmission that sets the time during which both clutches are connected at the same time by providing a function that disconnects the clutch that was previously connected with the other clutch after connecting the clutch. On the condition that the mode switching is started, the controller has a function of adjusting the engine speed independently of the driver's accelerator operation, and the mode switching is completed. A continuously variable transmission having a function of returning the rotational speed of the engine to that corresponding to the driver's accelerator operation on the condition of   On the condition that the connection of one clutch is started, the engine speed is maintained at the value at the time when the connection of this one clutch is started, and the connection of this one clutch is completed. The continuously variable transmission according to claim 1, wherein the engine speed is returned to a condition corresponding to a driver's accelerator operation.   On the condition that the connection of one clutch is started, the degree of change in the engine speed is maintained at the changing speed immediately before the connection of this one clutch is started, and the connection of this one clutch is maintained. 2. The continuously variable transmission according to claim 1, wherein the engine speed is returned to a value corresponding to a driver's accelerator operation on the condition that is completed.   On the condition that the connection of one clutch is completed, the target engine speed is obtained based on the accelerator opening and the vehicle speed at that time, and the engine speed is operated by adjusting to this target engine speed. The continuously variable transmission according to any one of claims 1 to 3, wherein the continuously variable transmission is returned to one corresponding to the accelerator operation of the user.   When switching from the low speed mode to the high speed mode, on the condition that the connection of the high speed clutch is started, the accelerator opening is reduced by a predetermined value from the value at the time when the connection of the high speed clutch is started. While maintaining the engine speed at the accelerator opening, and on completion of the connection of the high speed clutch, the accelerator opening is changed to the actual accelerator opening according to the accelerator operation of the driver at that time. The continuously variable transmission according to claim 1, wherein the continuously variable transmission is returned.   When switching from the high speed mode to the low speed mode, on the condition that the connection of the low speed clutch is started, the accelerator opening is increased by a predetermined value from the value at the start of the connection of the low speed clutch. While maintaining the engine speed at the accelerator opening, and the completion of the connection of the low speed clutch, the accelerator opening is changed to the actual accelerator opening according to the accelerator operation of the driver at that time. The continuously variable transmission according to claim 1, wherein the continuously variable transmission is returned. 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.

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