JP2016075335A - Toroidal-type continuously variable transmission - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a structure which can prevent the generation of an overshoot.SOLUTION: After a gear change ratio between an input disc and an output disc is started to be adjusted to a target gear change ratio by rotationally driving a gear change ratio control motor to a prescribed direction by a prescribed amount, when a difference between the target gear change ratio and an actual gear change ratio being a gear change ratio at the point in time between the input disc and the output disc becomes a prescribed value or smaller, a change speed of the gear change ratio between the input disc and the output disc is lowered compared with the case that the difference is larger than the prescribed value, by rotating the gear change ratio control motor to a direction reverse to the prescribed direction.SELECTED DRAWING: Figure 3

Description

  The present invention is used in, for example, automatic transmissions for vehicles (automobiles), automatic transmissions for construction machinery (construction machinery) and agricultural machinery (agricultural machinery), aircraft (fixed wing aircraft, rotary wing aircraft, airships, etc.) and the like. The present invention relates to an improvement of a toroidal continuously variable transmission that is used as an automatic transmission for a generator (generator) and an automatic transmission for adjusting the operating speed of various industrial machines such as pumps.

  The use of a toroidal-type continuously variable transmission as a transmission for an automobile is described in many publications such as Patent Document 1 and is partly implemented and well known. In addition, a continuously variable transmission that combines a toroidal type continuously variable transmission and a planetary gear type transmission that is a differential unit in order to increase the fluctuation range of the transmission ratio is also described in, for example, Patent Document 2, etc. Widely known. FIGS. 5 to 6 show a continuously variable transmission having a mode capable of realizing a so-called geared neutral state in which the output shaft is stopped while the input shaft is rotated in one direction, which is described in Patent Document 2. Show. FIG. 5 shows a block diagram of the continuously variable transmission, and FIG. 6 shows a hydraulic circuit for controlling the continuously variable transmission. First, the continuously variable transmission will be described with reference to the block diagram of FIG. In FIG. 5, a thick arrow indicates a power transmission path, a solid line indicates a hydraulic circuit, and a broken line indicates an electric circuit. 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 from the pressing device 5 constituting the toroidal type continuously variable transmission 4 to the input disk 6 and further transmitted to the output disk 8 through a plurality of power rollers 7. Each of these power rollers 7 is rotatably supported by a trunnion (not shown) that is a support member, and each of these trunnions is in a twisted position with respect to the central axes of the input disk 6 and the output disk 8. Oscillating displacement about the pivot 55 (see FIG. 6) is supported. The rotational speed of the input disk 6 is measured by the input-side rotation sensor 9, and the rotational speed of the output disk 8 is measured by the output-side rotation sensor 10, and is input to the controller 11, and the input disk 6 and the output disk are measured. 8 (toroidal-type continuously variable transmission 4) is calculated. As shown in FIG. 6 to be described later, the pressing device 5 is of a hydraulic type that generates a pressing force proportional to the hydraulic pressure as the hydraulic pressure is introduced.

  The power transmitted to the input shaft 3 is transmitted to the planetary gear unit 12 which is a differential unit directly or via the toroidal continuously variable transmission 4. Then, the differential component of the constituent members of the planetary gear device 12 is extracted to the output shaft 14 via the clutch device 13. The clutch device 13 represents a low speed clutch 15 and a high speed clutch 16 shown in FIG. Further, in the illustrated example, the output shaft rotation sensor 17 detects the rotation speed of the output shaft 14 to enable fail-safe for determining whether the input side rotation sensor 9 and the output side rotation sensor 10 are out of order. It is said.

  On the other hand, the oil pump 18 (18a, 18b in FIG. 6) is driven by the power extracted from the damper 2 portion, and the pressure oil discharged from the oil pump 18 is sent to the pressing device 5 and the power rollers 7 as described above. It can be fed to the control valve device 20 for controlling the displacement amount of the actuator 19 (see FIG. 6) that is displaced in the axial direction of each pivot 55. The control valve device 20 includes a control valve 21 shown in FIG. 6 described later, a differential pressure cylinder 22, correction control valves 23a and 23b, a high-speed switching valve 24, and a low-speed switching valve 25. It is a thing. Among these, the control valve 21 controls supply / discharge of pressure oil to / from each actuator 19. The hydraulic pressure in a pair of hydraulic chambers 26a, 26b (see FIG. 6) provided in each actuator 19 is detected by a hydraulic sensor 27 (actually, a pair of hydraulic sensors 27a, 27b as shown in FIG. 6). Then, the detection signal is input to the controller 11.

  Based on a signal from the hydraulic sensor 27 (difference between the hydraulic pressures in the hydraulic chambers 26a and 26b), the controller 11 passes through the toroidal continuously variable transmission 4 (passing torque, toroidal type The so-called 2Ft) known in the technical field of the step transmission is calculated. Then, in order to correct the transmission ratio of the toroidal type continuously variable transmission 4 according to the passing torque calculated in this way, a sleeve 28 (see FIG. 6) which is a component of the control valve 21 is connected to the differential pressure. It is displaced by the cylinder 22. The supply and discharge of the pressure oil to and from the differential pressure cylinder 22 is controlled by the correction control valves 23a and 23b. The control valve device 20 includes a stepping motor 29 that is a gear ratio control motor, a line pressure control electromagnetic on-off valve 30 for switching a pressing force adjusting valve 41 described later, and the correction control valves 23a and 23b. The operating state can be switched by a solenoid valve 31 for switching between and a shift solenoid valve 32 for switching between the high-speed switching valve 24 and the low-speed switching valve 25. The stepping motor 29, the line pressure control electromagnetic on-off valve 30, the electromagnetic valve 31, and the shift electromagnetic valve 32 are all switched based on a control signal from the controller 11.

  In addition to the signals from the rotation sensors 9, 10, 17 and the hydraulic pressure sensor 27, the controller 11 includes a detection signal from the oil temperature sensor 33, a position signal from the position switch 34, and an accelerator sensor 35. The detection signal and the signal of the brake switch 36 are input. Of these, the oil temperature sensor 33 detects the temperature of the lubricating oil (traction oil) in the casing that houses the continuously variable transmission. The position switch 34 emits a signal indicating an operation position (selection position) of a shift lever (operation lever) provided in the driver's seat for switching a manual hydraulic pressure switching valve 37 described later with reference to FIG. It is. The accelerator sensor 35 is for detecting the opening of the accelerator pedal. Further, the brake switch 36 detects that the brake pedal has been depressed or the parking brake has been operated, and issues a signal indicating that fact.

  Further, the controller 11 is configured to detect the stepping motor 29, the line pressure control electromagnetic on-off valve 30, and the like based on the signals from the switches 34, 36 and the sensors 9, 10, 17, 27, 33, 35. In addition to sending the control signal to the solenoid valve 31 and the shift solenoid valve 32, the control signal is sent to the engine controller 38 for controlling the engine 1. And the speed ratio between the input shaft 3 and the output shaft 14 is changed by controlling the gear ratio of the toroidal continuously variable transmission 4, or the toroidal continuously variable at the time of stopping or traveling at an extremely low speed. A torque (passing torque) applied to the output shaft 14 through the transmission 4 is controlled.

  FIG. 6 shows a hydraulic circuit for controlling the continuously variable transmission as described above. In this hydraulic circuit, the pressure oil sucked from the oil reservoir 39 and discharged by the oil pumps 18 a and 18 b can be adjusted to a predetermined pressure by the low pressure side adjustment valve 40 and the pressing force adjustment valve 41. Of these, the pressing force adjusting valve 41 for adjusting the hydraulic pressure to be sent to the pressing device 5 has a function as a relief valve, and includes first to third pilot portions 42 to 44. Of these, the first and second pilot parts 42 and 43 are for adjusting the valve opening pressure of the pressing force adjusting valve 41 according to the magnitude of the torque passing through the toroidal type continuously variable transmission 4. Is. On the other hand, the third pilot section 44 is a transmission ratio of the toroidal continuously variable transmission 4, the temperature of the lubricating oil (traction oil) existing in the toroidal continuously variable transmission 4, and a drive source. This is for adjusting the valve opening pressure of the pressing force adjusting valve 41 in accordance with operating conditions other than the transmission torque such as the rotational speed of an engine 1. In the case of the illustrated example, the pressing force generated by the pressing device 5 can be adjusted by appropriately adjusting the hydraulic pressure introduced into the first to third pilot portions 42 to 44 of the toroidal-type continuously variable transmission 4. It is configured to properly regulate according to the driving situation.

  For this reason, in the case of the illustrated example, the valve opening pressure of the pressure adjusting valve 41 increases as the hydraulic pressure introduced into any one of the first and second pilot portions 42 and 43 increases. And the hydraulic pressure introduced into the hydraulic chamber 45 constituting the pressing device 5 is increased. At the same time, the difference between the pair of hydraulic chambers 26a, 26b provided with the piston 46 sandwiched between the actuators 19 for displacing the trunnions supporting the power rollers 7 in the axial directions of the respective pivots 55. The pressure is introduced into one of the pilot portions 42 and 43 via the differential pressure take-out valve 47. The differential pressure take-off valve 47 is one of the pressure adjusting valves 41 as the difference between the hydraulic pressures in the hydraulic chambers 26a and 26b of the actuator 19, that is, the force passing through the toroidal continuously variable transmission 4 increases. These are switched so that the hydraulic pressure introduced into the pilot portions 42 and 43 increases. Therefore, the hydraulic pressure introduced into the hydraulic chamber 45 of the pressing device 5 and thus the pressing force generated by the pressing device 5 increases as the force passing through the toroidal type continuously variable transmission 4 increases.

  Further, in the illustrated example, pressure oil can be introduced into the third pilot section 44 based on switching of the line pressure control electromagnetic on-off valve 30 controlled by a command from the controller 11. That is, the controller 11 is generated in the pressing device 5 in consideration of the gear ratio of the toroidal-type continuously variable transmission 4, the temperature of the lubricating oil present therein, the rotational speed of the engine 1 as a drive source, and the like. Calculate the required value of hydraulic pressure according to the optimum value of the pressing force to be applied. Then, a hydraulic pressure corresponding to a correction value that is a difference between the necessary value and the target value is introduced into the third pilot section 44 based on the switching of the line pressure control electromagnetic on-off valve 30. The hydraulic pressure introduced into the third pilot portion 44 in this way pushes the spool 48 of the pressing force adjusting valve 41 to the left in FIG. 6 and reduces the hydraulic pressure introduced into the pressing device 5 ( Depressurize). As a result, the hydraulic pressure introduced into the pressing device 5 is proportional to a value obtained by subtracting a correction value based on the hydraulic pressure introduced into the third pilot section 44 from the target value set by the differential pressure take-out valve 47. It is corrected (reduced pressure) to the required value. The oil pressure introduced into the third pilot section 44 is such that the oil temperature decreases as the shift ratio increases from a predetermined value (a value that requires the largest oil pressure, for example, 1.32). Make each higher.

  Adjustment of the gear ratio of the toroidal type continuously variable transmission 4 incorporated in the continuously variable transmission as described above is carried out by using the trunnions supporting the power rollers 7 and the pivots 55 by the actuators 19. This is done by displacing in the axial direction. When these trunnions are displaced in the axial direction of the respective pivots 55, the circumferential surfaces of the respective power rollers 7 supported by the respective trunnions and the axial side surfaces of the input disk 6 and the output disk 8 are rolled. The direction of the tangential force acting on the contact portion (traction portion) changes (side slip occurs at the rolling contact portion). As each force changes, each trunnion swings about each pivot 55, and the peripheral surface of each power roller 7, the axial side surfaces of the input disk 6 and the output disk 8, and the like. The contact position changes. If the circumferential surface of each power roller 7 is brought into rolling contact with the radially outward portion of the axial side surface of the input disc 6 and the radially inward portion of the axial side surface of the output disc 8, the toroidal The speed ratio of the continuously variable transmission 4 is increased. In contrast, the peripheral surface of each power roller 7 is brought into rolling contact with the radially inward portion of the axial side surface of the input disc 6 and the radially outward portion of the axial side surface of the output disc 8. Then, the gear ratio of the toroidal type continuously variable transmission 4 is on the deceleration side. In any case, in a state where the transmission ratio of the toroidal-type continuously variable transmission 4 becomes a desired value, each traction is set to a neutral position (the centers of these traction portions are the input disk 6 and the output disk 8). To a state where it exists on a virtual plane perpendicular to the central axis of the pivot 55), the transmission ratio of the toroidal continuously variable transmission 4 can be maintained at the desired value. Each actuator 19 has an axial thrust load (toroidal) of each pivot 55 applied to each trunnion based on this power transmission while the toroidal continuously variable transmission 4 transmits power. In the field of the type continuously variable transmission, a force called “2Ft” is supported.

  As described above, a mechanism for adjusting the transmission ratio of the toroidal type continuously variable transmission 4 to a desired value and maintaining the adjusted value will be described with reference to FIG. 7 in addition to FIG. I will explain a little more in detail. This mechanism includes the control valve 21, the stepping motor 29, and a recess cam 56. Of these, the control valve 21 is a combination of the spool 57 and the sleeve 28 so as to be capable of relative displacement in the axial direction. Based on the relative displacement between the spool 57 and the sleeve 28, the oil pump 18 (18a, 18b) and the hydraulic chambers 26a and 26b of the actuator 19 are switched. The spool 57 and the sleeve 28 are relatively displaced by the movement of any one of the trunnions and the stepping motor 29. In the illustrated example, the movement of any one trunnion, that is, the axial displacement of the pivot 55 of any one trunnion and the oscillating displacement about the pivot 55 are represented by the precess cam 56 and the link. It is transmitted (feedback) to the spool 57 via the arm 58, and the spool 57 is displaced in the axial direction. On the other hand, the sleeve 28 is displaced in the axial direction by the stepping motor 29.

  When adjusting the gear ratio of the toroidal continuously variable transmission 4, the sleeve 28 is displaced to a predetermined position by the stepping motor 29, and the control valve 21 is opened in a predetermined direction. Then, pressure oil is supplied to and discharged from the hydraulic chambers 26 a and 26 b of the actuators 19 attached to the trunnions in a predetermined direction, and the trunnions are moved in the axial directions of the pivots 55 by the actuators 19. Be displaced. As a result, when the traction portions related to the power rollers 7 supported by the trunnions are displaced from the neutral position, the trunnions are displaced in the axial direction of the pivots 55 while the original positions (the respective positions While returning to the position of each of the trunnions in the axial direction of the respective pivots 55 in a state where the traction portion is present at the neutral position}, the pivotal displacement is performed around the pivots 55. Then, the movement (axial direction and swinging displacement) of the pivot shaft 55 of any one trunnion is transmitted to the spool 57 via the recess cam 56 and the link arm 58, and the spool 57 is displaced in the axial direction. . As a result, when each trunnion returns to its original position, the control valve 21 is closed, and the supply and discharge of the pressure oil to the hydraulic chambers 26a and 26b of each actuator 19 is stopped.

  The movement of the control valve 21 based on each trunnion and the feedback mechanism composed of the recess cam 56 and the link arm 58 at this time is as follows. First, when each trunnion is displaced in the axial direction of each pivot 55 by opening the control valve 21 in a predetermined direction, each trunnion is centered on each pivot 55 by a side slip generated in each traction section. Start swinging displacement. The displacement of the cam surface 59 of the recess cam 56 accompanying the axial displacement of the pivot shaft 55 of any one trunnion is transmitted to the spool 57 via the link arm 58, and the spool 57 is displaced in the axial direction. Then, the supply / discharge state to each actuator 19 by the control valve 21 is switched in a direction to return each trunnion to its original position.

  Accordingly, each trunnion starts to return toward the original position immediately after being displaced in the axial direction of the respective pivot shaft 55. However, each trunnion continues to swing around its pivot 55 as long as there is a displacement from its original position. As a result, the displacement in the circumferential direction of the cam surface 59 of the recess cam 56 is transmitted to the spool 57 via the link arm 58, and the spool 57 is displaced in the axial direction. Then, the inclination angle of each trunnion is obtained by a target gear ratio {a gear ratio obtained based on a value (vehicle speed, accelerator opening, etc.) representing the vehicle running state at that time, or an operation of the position switch 34. In the state where the predetermined angle commensurate with the gear ratio to be reached is reached, each trunnion returns to its original position, and at the same time, the control valve 21 is closed, and supply / discharge of pressure oil to each actuator 19 is stopped. Is done. As a result, the gear ratio of the toroidal type continuously variable transmission 4 is maintained at the desired value.

When a vehicle equipped with a continuously variable transmission as described above is suddenly accelerated or suddenly decelerated (emergency stop), that is, the gear ratio of the toroidal continuously variable transmission 4 is rapidly changed (shift speed). If the position of the stepping motor 29 is greatly displaced (the displacement amount in the axial direction of each pivot 55 of each trunnion is increased) as shown by a chain line α in FIG. The actual gear ratio (solid line β in FIG. 8), which is the gear ratio of the toroidal-type continuously variable transmission 4, exceeds the target gear ratio (broken line γ in FIG. 8) and converges to the target gear ratio. May cause overshoot (overshoot becomes significant). That is, when the gear ratio of the toroidal continuously variable transmission 4 changes abruptly, the spool 57 accompanies the axial displacement of the pivot shaft 55 of any one trunnion and the swing displacement about the pivot shaft 55. Is displaced in the axial direction and the control valve 21 is closed (the axial positions of the spool 57 and the sleeve 28 coincide with each other), and the trunnions can return to their original positions. Instead, the displacement from the original position exists. Accordingly, each of these trunnions continues to be displaced in the axial direction of the respective pivot shaft 55, and continues to swing and swing around the pivot shaft 55, so that the actual gear ratio exceeds the target gear ratio (overshoot occurs). ). Further, the control valve 21 is opened in a direction opposite to the predetermined direction. And even if each said trunnion returns to the original position, the said control valve 21 will be in the state opened in the direction opposite to the said predetermined direction. Then, each of these trunnions is displaced in the opposite direction with respect to the axial direction of the respective pivot shaft 55, and the transmission ratio of the toroidal-type continuously variable transmission 4 also starts to change in the opposite direction (the actual transmission ratio is changed). It begins to change back toward the target gear ratio). The above operation is repeated until the actual gear ratio converges to the target gear ratio.
When such an overshoot occurs, not only unpleasant acceleration / deceleration (the vehicle jerks) occurs and the engine speed increases rapidly (blows up). When the vehicle is stopped, the vehicle may tend to travel in the opposite direction with respect to the traveling direction.

JP 2004-169719 A JP 2010-190362 A

  The present invention has been invented in order to realize a structure of a toroidal continuously variable transmission that can prevent the occurrence of overshoot in view of the circumstances as described above.

The toroidal continuously variable transmission of the present invention includes an input disk and an output disk, a plurality of support members, a plurality of power rollers, an actuator, a transmission ratio control valve, a transmission ratio control motor, a feedback mechanism, A controller is provided.
Of these, the input disk and the output disk are supported concentrically and capable of relative rotation, with the inner surfaces of the toroidal curved surfaces each having an arcuate cross section facing each other.
Each of the support members is disposed between the input disk and the output disk in the axial direction of the input disk and the output disk, and is twisted with respect to the center axis of the input disk and the output disk. It swings around a certain axis.
Each of the power rollers is sandwiched between inner surfaces of the input disk and the output disk in a state of being rotatably supported by an intermediate portion of each of the support members.
The actuators are each hydraulic and are provided for each of the support members. By displacing the support members in the axial direction of the respective pivots, the respective support members are moved to the respective pivots. The gear ratio between the input disk and the output disk is changed by swinging and displacing to the center. However, by combining the support members with a mechanical synchronization mechanism, a hydraulic actuator can be provided on only one of the support members.
The transmission ratio control valve switches the supply / discharge state of the pressure oil to the actuator based on the relative displacement of a pair of members (for example, a sleeve and a spool).
The gear ratio control motor displaces one member (for example, a sleeve) of the pair of members constituting the gear ratio control valve.
Further, the feedback mechanism is configured to change the shift ratio control valve with respect to the displacement of the pivot of any one of the support members in the axial direction and the swing displacement about the pivot of any one of the support members. It transmits to the other member (for example, spool) of the pair of members constituting.
Further, the controller is for controlling the operation of each member constituting the toroidal type continuously variable transmission, and rotates the speed ratio control motor by a predetermined amount in a predetermined direction so as to support each of the support members. The gear ratio between the input disk and the output disk is adjusted to the target gear ratio by displacing the members in the axial directions of the respective pivots and swinging and displacing these support members about the respective pivot axes. It has a function.

  In particular, in the case of the toroidal type continuously variable transmission according to the present invention, the transmission ratio between the input disk and the output disk is determined based on the operating state of the toroidal type continuously variable transmission (for example, the toroidal type continuously variable transmission for a vehicle). In the case of a stepped transmission, after starting to adjust toward the target gear ratio, which is determined based on the accelerator opening, the operating position of the shift lever, the traveling state of the vehicle, etc., When the difference (absolute value) between the input disk and the output disk with respect to the actual speed ratio, which is the current speed ratio, becomes equal to or less than a predetermined value (threshold value), the speed ratio control motor is When the speed of change (shift speed) of the gear ratio (actual gear ratio) between the input disk and the output disk is larger than the predetermined value by rotating in a direction opposite to the predetermined direction. Slower than

  Preferably, when the toroidal continuously variable transmission of the present invention as described above is implemented, the speed change rate of the speed ratio before the difference between the target speed ratio and the actual speed ratio falls below the predetermined value is predetermined. When the difference between the target gear ratio and the actual gear ratio is less than or equal to a predetermined value only when the speed is equal to or higher than the speed, the gear ratio control motor is reversed from the predetermined direction. By rotating in the direction, the speed of change of the gear ratio is made slower than when the difference is larger than the predetermined value.

  Preferably, when carrying out the present invention, the controller rotates the speed ratio control motor in a direction opposite to the predetermined direction, and then sets the speed ratio control motor to the target speed ratio. It further has a function of rotating again in a predetermined direction by an appropriate amount (so that the rotation position corresponds to the target gear ratio).

  The toroidal continuously variable transmission of the present invention as described above includes, for example, an input member that is rotationally driven in one direction by a drive source such as an engine, a toroidal continuously variable transmission, a gear-type differential mechanism, It can be used by being incorporated in a continuously variable transmission configured by combining an output member for rotationally driving the driven part. In such a continuously variable transmission, the gear ratio between the input member and the output member is rotated in one direction by adjusting the gear ratio of the toroidal continuously variable transmission. The rotation direction of the output member can be changed in both directions with the stop state sandwiched in the state (a geared neutral state can be realized).

  According to the toroidal continuously variable transmission of the present invention configured as described above, it is possible to prevent the occurrence of overshoot. For this reason, for example, when this toroidal-type continuously variable transmission is incorporated in a vehicle, it is possible to prevent unpleasant acceleration / deceleration (the vehicle jerks) and a sudden increase in engine speed (a blow-up). Also, when it is incorporated into a continuously variable transmission equipped with an operation mode that realizes a geared neutral state, the output member rotating in a predetermined direction is urgently stopped while the input member is rotated. The output member can be prevented from rotating in the direction opposite to the predetermined direction.

1 is a block diagram showing an example of a continuously variable transmission according to the present invention. The figure which similarly shows one example of a hydraulic control circuit. The flowchart which shows the control operation | movement used as the characteristic of one example of embodiment of this invention. Similarly, a diagram for explaining the effect. The block diagram which shows one example of the continuously variable transmission conventionally known. The figure which similarly shows one example of a hydraulic control circuit. FIG. 3 is a schematic cross-sectional view of a hydraulic control device portion for gear ratio control. The diagram for demonstrating the problem of a conventional structure.

1 to 4 show an example of an embodiment of the present invention. FIG. 1 shows an example of a continuously variable transmission according to the present invention, and FIG. 2 also shows a hydraulic control circuit. The configuration of this continuously variable transmission is basically described above. This is the same as in the case of the conventional structure shown in FIGS. In FIG. 1, a paddle shift sensor 49 for obtaining a paddle shift signal for manually changing the gear ratio, a parking brake sensor 50 for obtaining a signal indicating whether or not the parking brake is operated, and a driver Mode detection for determining the switching state between the high speed and low speed modes based on the switching of the clutch device 13, the brake sensor 51 for obtaining the brake pedal operation status by, the acceleration sensor 52 for obtaining the acceleration applied to the vehicle body, A signal to the means 53 is input to the controller 11 and the controller 11 and the arithmetic unit 54 are connected, but these points are not related to the essence of the present invention. The brake sensor 51 may be a rotation angle stroke sensor as in the case of the accelerator sensor 35, or a pressure sensor or the like attached to the brake piping path.
The hydraulic circuit shown in FIG. 2 is simplified compared to the above-described conventional structure, such as omitting the differential pressure cylinder 22 and the differential pressure take-off valve 47 (see FIG. 6). It is not related to the essence of the present invention. That is, the present invention can be implemented with the structure shown in FIGS.

Next, control for preventing overshoot, which is a feature of this example, will be described with reference to FIGS. Note that the operation shown in FIG. 3 is that the actual gear ratio e ₀ , which is the gear ratio of the toroidal continuously variable transmission 4 at that point in time, is at least after the shifting operation of the toroidal continuously variable transmission 4 is started. (the operation amount of the accelerator opening, brake, vehicle speed, etc.) the driving state of the vehicle at that time is repeated in until it converges to the target speed ratio e _t obtained based on the value representing the.
First, in step 1, the actual gear ratio e ₀ in a state before starting the shift operation, or matches the target gear ratio e _t, i.e., with these target gear ratio e _t and the actual speed ratio e ₀ It is determined whether or not the absolute value of the difference (| e _t −e ₀ |) is greater than a preset first threshold value δ ₁ (for example, about 0.01). In step 1, the difference is less than or equal to ₁ [delta] This first threshold value _{(| e t -e 0 | ≦} δ 1), i.e., the actual gear ratio _{e 0} is the target gear ratio _{e t} substantially If it is determined that they match, the transmission is terminated without performing the shift operation (returns to the start).

Meanwhile, in the step 1, the difference is greater than the first threshold value _{δ 1 (| e t -e 0} |> δ 1), i.e., the actual gear ratio _{e 0} is coincident with the target gear ratio _{e t} If it is determined not with, the process proceeds to step 2, the real speed ratio drive of the stepping motor 29 required to match the e ₀ in the target gear ratio e _t (number of pulses n) and driving speed (pulse Speed p: number of pulses per unit time) is calculated. Of these, the number of pulses n of the stepping motor 29 is calculated as follows, for example. That is, a correlation between the position of the stepping motor 29 (step position) and the transmission ratio of the toroidal continuously variable transmission 4 is obtained in advance by experiments and calculations, and this correlation is stored in the memory of the controller 11 in a map or It may be stored as a formula, based on the correlation obtained by the storage, determining the step position corresponding to the target speed ratio e _t. Then, the pulse number n is obtained by obtaining the difference between the step position corresponding to the target speed ratio _et and the step position at that time. The pulse speed p can be determined based on, for example, the number of pulses n and a value representing the running state of the vehicle. However, the pulse speed p can be a constant value regardless of the number of pulses n and the value representing the running state of the vehicle.

Then, in Step 3, after said stepping motor 29 is driven in the pulse number n min predetermined direction by said pulse rate p, stops the stepping motor 29 to step the position corresponding to the target gear ratio e _t, the following Go to step 4. In this step 4, it is determined whether or not the shift speed v of the toroidal type continuously variable transmission 4 is larger than a predetermined speed (threshold) ε. The predetermined speed epsilon, the a target gear ratio e _t, the absolute value of the difference between the time at (during the shift operation performed) actual speed ratio e _n is the transmission ratio of the toroidal continuously variable transmission 4 It is a value set based on (| e _t −e _n |) or the like. If it is determined in step 4 that the shift speed v of the toroidal continuously variable transmission 4 is equal to or less than the predetermined speed ε (v ≦ ε), the stepping motor 29 is moved to the target speed ratio e. _{The process} ends (returns to the start) while being stopped at the step position corresponding to _t .

In step 4, the case where the shift speed v is judged to be the greater than the predetermined speed epsilon (v> epsilon), then control goes to step 5, and the target speed ratio e _t the the actual speed ratio e _n the absolute value of the difference is equal to or second threshold [delta] ₂ or less. The second threshold value δ ₂ is a value (δ ₂ > δ ₁ ) that is larger than the first threshold value δ ₁ , and is set in the range of 0.1 to 0.2, for example. Alternatively, the second threshold value [delta] ₂ can also be variable in accordance with the shift speed v. If it is determined in step 5 that the absolute value of the difference is larger than the second threshold value δ ₂ (| e _t −e _n |> δ ₂ ), the stepping motor 29 is moved to the target speed change. remain stopped in step position corresponding to the ratio e _t, after a predetermined time has elapsed, the flow returns to the step 4.

In contrast, in the step 5, the absolute value is the second threshold value [delta] ₂ following the difference if it is determined _{(| | e t -e n ≦} δ 2) and, next step 6, the It determines whether the absolute value of the difference between the target speed ratio e _t said the actual speed ratio e _n is greater than the first threshold value [delta] _1. In step 6, the absolute value of this difference is the first threshold value [delta] ₁ below _{(| e t -e n | ≦} δ 1), i.e., the actual gear ratio _{e n} is said target gear ratio _{e t} If it is determined that they match, the process ends without returning to the start without performing control for preventing overshoot.

In step 6, the absolute value of the difference is greater than the first threshold value [delta] ₁ when it is determined _{(| | e t -e n>} δ 1) and proceeds to the next step 7. In step 7, the stepping motor 29, the opposite direction to the predetermined direction (direction of driving in step 3), to drive a predetermined number of pulses n _A minute. In other words, the stepping motor 29 is returned by the pulse number n _A from the target step position. As a result, the sleeve 28 constituting the control valve 21 is displaced in a direction in which the amount of relative displacement with respect to the spool 57 is reduced, and the difference in hydraulic pressure in the pair of hydraulic chambers 26 a and 26 b constituting the actuator 19 is reduced. Further, by displacing the sleeve 28 from this state, the hydraulic pressure in the hydraulic chambers 26a and 26b is reversed, and the trunnions that respectively support the power rollers 7 based on the hydraulic pressure difference. The force in the direction opposite to the displacement direction with respect to the axial direction of the pivot 55 of each trunnion is applied. As a result, the displacement of each trunnion in the axial direction of each pivot 55 is decelerated (displacement speed is reduced). In the case of this example, the predetermined number of pulses n _A is variable according to the shift speed (actual shift speed) v of the toroidal-type continuously variable transmission 4 at that time. Specifically, the predetermined number of pulses n _A is set so that the shift speed v can be made sufficiently small (ideally zero) when each traction section returns to the neutral position. Set.

In the next step 8, whether or not the speed change operation of the toroidal type continuously variable transmission 4 has been decelerated corresponding to the driving of the stepping motor 29 by the predetermined number of pulses n _{A in the} step 7, that is, The speed v of the toroidal continuously variable transmission 4 at that time is determined from the speed v ₀ of the toroidal continuously variable transmission 4 before the stepping motor 29 is driven by the predetermined number of pulses n _A. It is determined whether or not the speed is equal to or less than a target shift speed v _t (= v ₀ −Δv), which is a value obtained by subtracting the speed decrease amount Δv corresponding to driving by the predetermined number of pulses n _A. In step 8, it is determined that the speed change speed v is higher than the target speed change speed v _t (v> v _t ), that is, the speed change operation of the toroidal type continuously variable transmission 4 is not sufficiently decelerated. case, in a state where the stopping of the stepping motor 29 to the exact step position (position after driving the pulse number n _a minute), after a predetermined time has elapsed, the flow returns to the step 8.

In Step 8, the speed v of the toroidal continuously variable transmission 4 is equal to or lower than the target speed v _t (v ≦ v _t ), that is, the speed change operation of the toroidal continuously variable transmission 4 is sufficiently decelerated. If it is determined, the process proceeds to step 9. In this step 9, the stepping motor 29 is driven in the predetermined direction by the predetermined number of pulses n _A (returning the amount driven in step 7), the stepping motor 29, moves to the step position corresponding to the target gear ratio e _t, the speed ratio of the toroidal continuously variable transmission 4 after being converged to the target speed ratio e _t, and ends (the starting Return).

According to the continuously variable transmission of such the example above, the when the actual speed ratio e _n reaches the vicinity of the target gear ratio e _t, the shift operation of the toroidal-type continuously variable transmission 4 is sufficiently decelerated that reason, the actual speed ratio e _n exceeds the target speed ratio e _t (too far), it is possible to prevent the occurrence of overshoot. For this reason, even when a vehicle equipped with the continuously variable transmission is suddenly accelerated or decelerated, unpleasant acceleration / deceleration (the vehicle jerks) or a sudden increase in engine speed (swelling up) occurs. You can prevent things. In addition, even when the vehicle is urgently stopped (even when the rotation of the output shaft 14 is urgently stopped while the input shaft 3 is rotated), the vehicle is sure to try to travel in the opposite direction. Can be prevented.

More specifically, in the case of the present embodiment, for example in order to urgently stop the vehicle, and operates rapidly the brake, as shown in chain line alpha ₁ in FIG. 4, the position of the stepping motor 29 is, the number of steps is reduced Changes rapidly in direction. As the position of the stepping motor 29 changes, the trunnions are displaced in the axial directions of the pivots 55, and the shifting operation of the toroidal continuously variable transmission 4 is started. When the difference between the target speed ratio e _t (broken line γ _{1 in} FIG. 4) and the actual speed ratio e _n (solid line β _{1 in} FIG. 4) becomes about 0.15 or less (time t in FIG. 4). _{In step A} ), the stepping motor 29 changes the step position in the direction in which the number of steps increases by about 20 steps, and stops at that position for a predetermined time T. Thereby, a force in the direction opposite to the displacement direction with respect to the axial direction of each pivot 55 can be applied to each trunnion, and the shift speed v of the toroidal-type continuously variable transmission 4 can be reduced. As a result, the actual speed ratio e _n is the speed ratio e _GN can realize geared neutral state which is the target speed ratio e _{t (in} the case of the illustrated example, about 1.3) can be prevented that exceeds the It is possible to reliably prevent the vehicle from going in the opposite direction. Incidentally, the stepping motor 29, after the predetermined time T, allowed to displace the step position corresponding to the target speed ratio e _t.

  The toroidal type continuously variable transmission that is the subject of the present invention is not limited to a half toroidal type but also includes a full toroidal type. In the case of the half toroidal type, pivots are provided concentrically with each other at both ends of the trunnion as each support member. However, in the case of the full toroidal type, the pivot may be provided only at one end of each support member. . Further, it can be implemented by a so-called single cavity type in which one input disk and one output disk are provided, or a so-called double cavity type in which one pair is provided. In addition, an actuator for displacing each support member in the axial direction of the pivot is generally provided for each of these support members, but each support member is provided by a mechanical synchronization mechanism such as a link mechanism or a gear transmission mechanism. By combining, the actuator can be assembled only to any one of the support members.

DESCRIPTION OF SYMBOLS 1 Engine 2 Damper 3 Input shaft 4 Toroidal type continuously variable transmission 5 Press device 6 Input side disk 7 Power roller 8 Output side disk 9 Input side rotation sensor 10 Output side rotation sensor 11 Controller 12 Planetary gear device 13 Clutch device 14 Output Shaft 15 Low speed clutch 16 High speed clutch 17 Output shaft rotation sensor 18, 18a, 18b Oil pump 19 Actuator 20 Control valve device 21 Control valve 22 Differential pressure cylinder 23a, 23b Correction control valve 24 High speed switching valve 25 Low speed switching Valve 26a, 26b Hydraulic chamber 27, 27a, 27b Hydraulic sensor 28 Sleeve 29 Stepping motor 30 Line pressure control electromagnetic on-off valve 31 Electromagnetic valve 32 Shifting electromagnetic valve 33 Oil temperature sensor 34 Position switch 35 Acceleration sensor 36 Brake switch 37 Manual hydraulic pressure switching valve 38 Engine controller 39 Oil reservoir 40 Low pressure side adjustment valve 41 Push pressure adjustment valve 42 First pilot part 43 Second pilot part 44 Third pilot part 45 Hydraulic chamber 46 Piston 47 Differential pressure take-off valve 48 Spool 49 Paddle Shift Sensor 50 Parking Brake Sensor 51 Brake Sensor 52 Acceleration Sensor 53 Mode Detection Means 54 Calculator 55 Axis 56 Precess Cam 57 Spool 58 Link Arm 59 Cam Surface

Claims (1)

An input disk and an output disk supported so as to be concentric with each other and capable of relative rotation in a state in which the inner side surfaces of the respective toroidal curved surfaces each having a circular arc shape are opposed to each other,
Each of them is arranged in a portion between the input disk and the output disk with respect to the axial direction of the input disk and the output disk, and swings around a pivot that is twisted with respect to the central axis of the input disk and the output disk. A plurality of support members;
A plurality of power rollers sandwiched between inner surfaces of the input disk and the output disk in a state of being rotatably supported by intermediate portions of these support members;
By displacing the support members in the axial direction of the respective pivots, the support members are oscillated and displaced about the respective pivots so that the gear ratio between the input disk and the output disk is increased. Changing hydraulic actuators,
A transmission ratio control valve that switches a supply / discharge state of pressure oil to the actuator based on a relative displacement of the pair of members;
A gear ratio control motor for displacing one member of the pair of members constituting the gear ratio control valve;
The pair of members constituting the transmission ratio control valve are defined as a displacement in the axial direction of the pivot of any one of the support members and a rocking displacement about the pivot of any one of the support members. A feedback mechanism for transmitting to the other member,
By rotating the gear ratio control motor by a predetermined amount in a predetermined direction, displacing the support members in the axial directions of the respective pivots, and swinging and displacing these support members around the respective pivots, In a toroidal continuously variable transmission comprising: a controller having a function of adjusting a gear ratio between the input disk and the output disk to a target gear ratio;
After starting to adjust the gear ratio between the input disk and the output disk toward the target gear ratio, the target gear ratio and the current gear ratio between the input disk and the output disk When the difference from a certain actual gear ratio is equal to or less than a predetermined value, the gear ratio between the input disk and the output disk is rotated by rotating the speed ratio control motor in a direction opposite to the predetermined direction. A toroidal-type continuously variable transmission characterized in that the change speed of the torsion is made slower than when the difference is greater than the predetermined value.

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