JPH07259948A - Toroidal type continuously variable transmission - Google Patents

Abstract

PURPOSE:To prevent reduction of the transmission efficiency attributed to the friction loss or the like under the stationary condition where the change gear ratio is constant, and prevent reduction of the transmission efficiency attributed to the excessive slip during the speed change. CONSTITUTION:The power transmission from an input disk 12 to an output disk 13 is through a power roller 23 pressed against the opposite surface of the disks 12, 13, and the pressing force of the power roller 23 against the input and output disks 12, 13 is changed according to the input torque. A device is provided with a speed change operating means 45a and a pressure application control signal correcting means 45b which corrects the pressing force of the power roller based on the changed speed obtained by this speed change operating means 45a, and increased the pressing force of the power roller the more as the changed gear speed is increased the more.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a toroidal type continuously variable transmission used in automobiles and the like, and more particularly to a pressing force control device for its power roller.

[0002]

2. Description of the Related Art A toroidal type continuously variable transmission is a device that presses an input / output disk and a power roller with a large force to transmit power by means of a shear resistance of an oil film between them. The input / output disc and the power roller make a rotary motion with a slight slip between them.

As described above, although slippage is inevitable during power transmission by the toroidal type continuously variable transmission, if it becomes too large, the transmission efficiency decreases, and on the other hand, slippage becomes small. In order to increase the transmission efficiency by increasing the pressing force between both disks and the power roller, if the pressing force becomes excessive,
The frictional force of each part of the device is increased, the transmission efficiency is inevitably decreased due to the increase of frictional loss, and the weight and the cost are inevitably increased as the strength of the supporting portion of the pressing reaction force is increased. .

[0004]

For this reason, JP-A-1
-255758, Japanese Patent Laid-Open No. 62-258254, etc. propose a continuously variable transmission capable of changing the pressing force of the power roller against the input / output disk. However, for the purpose of avoiding a reduction in transmission efficiency due to an increase in slip, in particular, the power roller causes a rotational movement (hereinafter referred to as “tilting”) around an axis orthogonal to the rotation axis. Even at the time of gear shifting, since a large power roller pressing force that does not cause an excessive slip is applied, the transmission efficiency in the steady state without gear shifting is deteriorated.
The problem of increasing the weight and cost of the device due to the increase in the strength of the pressing reaction force supporting portion has not been solved.

The present invention has been made as a result of investigations aimed at solving the problems of the prior art. The object of the present invention is to reduce the power roller pressing force at the time of shifting to the shifting speed. By controlling in accordance with the above, the power roller pressing force at the time of gear shifting should be appropriately adjusted so as not to cause an excessive slip, and the transmission efficiency should be sufficiently enhanced without lowering the transmission efficiency at the time of steady state without gear shifting. (EN) Provided is a toroidal type continuously variable transmission capable of achieving

[0006] Here, as a conventional technique for preventing a slip during a sudden shift, there is a continuously variable transmission disclosed in Japanese Unexamined Patent Publication (Kokai) No. 58-191361. In a belt-type continuously variable transmission that changes the contact position of the belt with respect to the pulley in the radial direction, it is intended to prevent the hydraulic pressure pushing the pulley from decreasing due to a sudden stroke of the variable pulley during a sudden gear shift. Since the toroidal type continuously variable transmission according to the present invention always maintains the relative position of the input / output disk at a constant position regardless of the gear ratio, both of them have the idea of solving the technical problem. It is different.

In other words, the present invention was made by paying attention to the slip of the power roller caused by the "tilt" of the power roller during the gear shift operation of the apparatus, whereas the belt type The speed change device is made by paying attention to the V-belt slip generated by the stroke speed of the variable pulley, and these points are completely different.

[0008]

According to the present invention, the pressing force of a power roller against an input / output disk is controlled according to an input torque to an input shaft and a shift speed corresponding to a tilting speed of the power roller. Then, the pressing force is always made proper, and therefore, the power transmission from the input disk to the output disk, which is arranged coaxially with the input disk in many cases, is applied to the opposing surfaces of both disks. In the toroidal type continuously variable transmission in which the pressing force of the power roller against the input / output disk is changed according to the input torque, the speed change speed calculation means is provided and the speed change speed calculation means is used. The pressure control signal correcting means is provided to correct the power roller pressing force based on the speed change speed and increase the power roller pressing force as the speed change speed increases. That.

In another toroidal type continuously variable transmission according to the present invention, in particular, a shift speed calculating means and an engine generated torque calculating means are provided, and based on the shift speed and the torque signal obtained by these respective means. The engine-generated torque is corrected by correcting the engine-generated torque by increasing the engine-generated torque as the gear shift speed increases.

[0010]

The power transmitted to the input disk of the toroidal type continuously variable transmission is transmitted to the output disk through the rotation of the power roller based on the friction engagement between the input / output disk and the power roller. When the power roller is tilted during such transmission of power, the contact point between the power roller and both discs continuously changes, and stepless speed change is realized. During such power transmission, slips due to rotation of the power roller and slips due to tilting of the power roller during gear shifting occur. Therefore, when transmitting the same power, the total slip amount during gear shifting is larger than when the gear ratio is constant.

When power is transmitted through the power roller as described above, it is essential to allow a predetermined amount of slip for tilting the power roller. When the total slip amount, which is the sum of the slip and the slip due to its rotation, exceeds the critical value, the friction coefficient between the input / output disk and the power roller sharply decreases, which further increases the total slip amount. Increasing, the transmission efficiency will also drop significantly.

According to the present invention, there is no fear of reduction in transmission efficiency, and in particular, slippage due to tilting of the power roller is effectively prevented to sufficiently prevent the above-mentioned reduction in transmission efficiency.

Here, in the former device including the speed change speed calculation means and the pressurization control signal correction means, the speed change speed calculation means calculates the speed change speed based on the throttle opening signal and the vehicle speed signal, The pressurizing control signal correcting means determines the pressing force so that the pressing force between the input / output disk and the power roller increases as the shift speed increases, so that the pressing force is excessive regardless of the shift speed. It is possible to sufficiently reduce the pressing force in the range where slip does not occur, which prevents the decrease in transmission efficiency and the increase in the weight and cost of the device due to the excessive pressing force. It is possible to effectively prevent a reduction in transmission efficiency due to excessive slip.

The same applies to the latter device including the speed change speed calculation means, the engine generated torque calculation means, and the generated torque correction means. In this case, in particular, the accelerator operation amount and the engine rotation speed. The engine generated torque is calculated from the number and the steady pressing force corresponding to the input torque to the input shaft, which is calculated from the engine generated torque and the gear ratio at that time, and the gear change speed are also taken into consideration. The shortage of the pressing force of the power roller, and by extension, the shortage of the torque generated by the engine to generate the shortage of the pressing force by the loading cam, is calculated from the difference between the transient required pressing force, and only the shortage is obtained. By adjusting the accelerator opening to increase the engine generated torque,
It is possible to effectively prevent an increase in slip when the shift speed is high.

[0015]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a view showing an embodiment of the present invention. Here, for convenience, a cross section taken along line I-I at the upper right of the drawing is shown on the left side of the drawing. In the figure, 10 indicates a transmission case, and 11 indicates an input shaft bearing on the transmission case 10. Here, the input disk 12 is integrally mounted on the input shaft, and the output disk 13 is provided coaxially with the input disk 12. Here, the output disk 13 is integral with a hollow output shaft 14 rotatably supported on the input shaft. The input shaft 11 is connected to an engine (not shown), and power is transmitted from the engine.

Further, the output gear 1 is further provided on the hollow output shaft.
5, the inner race 16a of the thrust bearing 16 is mounted immovably in the axial direction, and the outer race 16b of the thrust bearing 16 is attached to the transmission case 10. It is fitted and fixed in the attached cylinder 17.

Here, a hydraulic piston 18 is slidably fitted on the inner circumference of the cylinder 17 to define a hydraulic chamber 19 between the two, while outside the hydraulic chamber 19,
The outer race 20a of the thrust bearing 20 that is coaxially abutted on the hydraulic piston 18 is fitted into the partition wall 21 attached to the transmission case 10 so as to be slidable in the axial direction thereof. The inner race 20b of the thrust bearing 20 is coupled to the input shaft 11 via the ring 22.

Further, a pair of two power rollers 23, which are located so as to oppose each other in the diametrical direction of both the disks 12 and 13, are frictionally engaged with the mutually facing surfaces 12a and 13a of the input disk 12 and the output disk 13. These power rollers 23, which are arranged in parallel with each other and are separated from each other by the input shaft 11, are provided with respective tilting shafts 24.
It is rotatably supported about a common axis 23a orthogonal to the central axis of the. Here, each tilting shaft 24 has a tilting axis 23b orthogonal to the rotation axis 23a of the power roller 23.
In order to allow its pivoting movement around the
5,26. And each tilt axis 2
Of the bearings 25 located at the upper end of 4 and
The bearings 26 located at the lower end are connected to each other by respective tie rods 27 and 28. In addition, each of these tie rods 27 and 28 is
It is articulated to the transmission case 10 via joints 29 and 30.

Further, pistons 31 and 32 are provided at the upper and lower ends of the respective tilting shafts 24, and the pistons 31 and 32 are fitted into the transmission case 10 to form the hydraulic chambers 33 and 34. Define. Under such a configuration, when the hydraulic pressure is supplied to either one of the hydraulic chambers 33 and 34 to displace the one tilting shaft 24 upward or downward, the other tilting shaft 24 becomes tie rod 27, Two
Under the action of the joint 8 and the joints 29 and 30, the tilting shaft 24 is displaced in the opposite direction. Therefore, it is necessary to supply and discharge the hydraulic pressure to and from the respective hydraulic chambers 33 and 34 in the respective tilting shafts 24 in reverse. In addition, a rod 24a that extends coaxially with the tilt axis 23b is provided at the upper end of one of the tilt shafts 24, and the cam 35 is fixed to this rod 24a.

In order to supply the required hydraulic pressure to the above-mentioned mechanical components, here, the hydraulic pump 40 is provided with a hydraulic control valve 41 for the tilting shaft hydraulic chambers 33 and 34, and a pressing force control hydraulic pressure. It connects to each of the hydraulic control valves 42 for the chambers 19 and also these respective hydraulic control valves 41, 42 in signal connection to a control unit 45 which supplies control signals 43, 44 to them respectively. In addition, this control unit 45,
The throttle opening signal 46 from the throttle sensor and the vehicle speed signal 47 from the vehicle speed sensor are input.

The operation of the apparatus thus configured is as follows. The power reaching the input disk 12 from the input shaft 11 is transmitted to the output disk 13 through the rotation of the power roller 23, and then the output shaft 14 outputs the power to the output gear 1.
5 is transmitted and output.

When the driver operates the accelerator during such power transmission, it is input to the control unit 45 as a throttle opening signal 46, and the control unit 45 outputs the throttle opening signal 46.
Based on the vehicle speed signal 47 and a predetermined control logic, the control signal 43 is output to the hydraulic control valve 41 to change the gear ratio. As a result, the hydraulic control valve 4
1 performs hydraulic control of the hydraulic chambers 33 and 34, and the tilting shaft 24
Is displaced upward or downward from the hollow position shown.
As a result, the power roller 23 receives the tilt component force from the input / output disks 12 and 13, and tilts in either direction around the tilt axis 23b.

Such tilting movement of the power roller 23 causes the power roller 23 and the input / output disks 12, 1 to move.
A change in the friction engagement position with each of the three is brought about, whereby a continuous shift is performed. When the gear ratio reaches a predetermined value by such a shift, the hydraulic control of the hydraulic chambers 33 and 34 is performed under the operation of the hydraulic control valve 41 to return the tilt shaft 24 to the neutral position shown in the figure. Due to
The tilting component force acting on the power roller 23 is removed, and the power roller 23 is maintained in the changed tilting posture that provides the predetermined gear ratio.

Here, the cam 35 attached to the tilting shaft 24 detects the tilting angle of the tilting shaft 24 and the ascending / descending amount of the tilting shaft 24, and thus the power roller 23, and detects them. The signal is fed back to the hydraulic control valve 41.

By the way, in the shifting operation as described above, the hydraulic pressure in the hydraulic chamber 19 is controlled by the hydraulic control valve 42 which operates based on the control signal 44 from the control unit 45, and the power roller 23 is moved between the input and output disks. The hydraulic pressure Pa in the hydraulic chamber 19 presses the cylinder 17 and the hydraulic piston 18 with the force Fa in a direction in which they are separated from each other, and acts on the hydraulic piston 18. The pressing force applied from the input shaft 11 to the input disk 12 via the thrust bearing 20 and the ring 22 causes the power roller 23 to
The input and output disks will be pinched with the expected force.

Here, the control unit 45
The hydraulic control by is performed as follows according to the flowchart shown in FIG. First, step 10
In each of 0 and 110, the throttle opening signal 46 and the vehicle speed signal 47 are read into the control unit 45, and then the speed ratio calculating means 45e and the speed changing speed calculating means 45a in the control unit are read.
Under the action of, the following steps 120 and 130 are performed.

Here, in step 120, the target gear ratio is calculated based on the changes in the throttle opening signal 46 and the vehicle speed signal 47 by a predetermined gear shift control map or control logic, and in step 130, The shift speed is calculated from the actual gear ratio and the target gear ratio.

Then, in step 140, a shift control signal is generated from the target gear ratio and the shift speed. This generated signal is used as the control signal 43 by the hydraulic control valve 41.
And contributes to the control of the displacement amount and displacement speed of the tilting shaft 24. Here, the displacement amount of the tilting shaft 24 determines the tilting amount of the power roller 23, and thus the gear ratio, and the displacement speed of the tilting shaft 24 determines the tilting speed of the power roller 23 and thus the gear shifting speed. To do.

At step 150, the input torque value to the input shaft 11 is estimated from the throttle opening signal 46,
At step 160, a steady pressing force corresponding to the input torque value is calculated. Thereafter, the pressurization control signal correction means 45b in the control unit calculates the correction amount of the pressing force from the shift speed and the input torque value in step 170, and further executes the following steps 180 and 190. . By the way, the correction amount of the pressing force is
The larger the shift speed and the smaller the input torque, the larger the shift speed. Here, the correction of the pressing force may be performed only according to the shift speed.

In step 180, the pressing force obtained in step 160 is added to the correction amount of the pressing force obtained in step 170, and in step 190, step 18 is added.
A pressing force control signal is generated based on the calculation result of 0. The generated signal here is input to the hydraulic control valve 42 as the control signal 44 so that the pressing force of the power roller 23 against the input / output disks 12 and 13 is set to an appropriate value in accordance with both the gear shift and the transmission torque. Function.

Thus, according to this apparatus, the power roller pressing force generated based on the action of the hydraulic control valve 42 is controlled in consideration of not only the input torque to the input shaft but also the speed change speed. , The pressing force can always be made appropriate, and therefore, the decrease in transmission efficiency and the increase in the weight and cost of the device due to the excessive pressing force are sufficiently prevented, It is possible to eliminate the risk of a reduction in transmission efficiency, particularly during a gear shift, due to insufficient power.

FIG. 3 is a diagram showing another embodiment of the present invention, in which a cam disk 36 is provided at the shaft end portion of the input shaft 11.
And the opposing surfaces of the cam disc 36 and the input disc 12 are both cam faces, and the follower roller 37 disposed between both cam faces makes the input disc respond to the torque. A loading cam 50 for generating a power roller pressing force is provided. still,
For details of the loading cam 50, see Japanese Patent Laid-Open No. 1-257575.
Since the structure is generally well known in Japanese Patent No. 8 etc.,
The detailed description thereof is omitted here.

In the control of the pressing force, the engine torque generation amount is estimated from the accelerator operation amount, the insufficient torque is calculated from the estimated value, and the throttle opening is controlled by the throttle-by-wire to correspond to the insufficient torque. This is done by increasing the generated torque by the amount.

Therefore, the oil pump 40 is used here.
To the respective hydraulic chambers 3 via the hydraulic control valve 41.
3, 34, and its hydraulic control valve 41
Then, the control unit 45 to which the vehicle speed signal 47 and the accelerator operation amount signal 48 are respectively input is signal-connected. Here, the control unit 45 sends the shift speed calculation means 45a, the input torque calculation means 45c for estimating the generated torque of the engine, and the throttle opening command signal to a throttle opening control controller (not shown). And a generated torque correction means 45d that outputs the generated torque.

The operation of the apparatus thus configured will be described below with reference to the flow chart shown in FIG. First, in steps 200 and 210, the control unit 45 reads the accelerator operation amount signal 48 and the vehicle speed signal 47, respectively, and then, the speed ratio calculating means 45e and the speed changing speed calculating means 4 in the control unit.
In step 5a, steps 220 and 230 are performed.

That is, at step 220, based on changes in the accelerator operation amount signal 48 and the vehicle speed signal 47,
The target gear ratio is calculated by a predetermined gear shift control map or control logic, and in step 230, the gear shift speed is calculated from the current gear ratio and the target gear ratio.

Then, in step 240, a gear shift control signal is generated from the target gear ratio and the gear shift speed, and this is output to the hydraulic pressure control valve 41 as a control signal 43. After that, the engine generated torque calculation means 45c estimates the engine generated torque from the accelerator operation amount and the engine speed in step 250.

Further, in the generated torque correction means 45d,
The following steps 260, 270 and 280 are performed. In step 260, the pressing force deficiency is calculated from the calculated speed change value and the engine generated torque estimation value, in step 270, the torque deficiency is calculated from the calculation result, and in step 280, the step is calculated. A throttle opening command value is obtained from the torque shortage at 270, the accelerator operation amount signal 48, and the vehicle speed signal 47, and is output as a throttle opening command signal 49 to a throttle opening control controller (not shown). Here, the throttle opening command value becomes larger as the gear shift speed is faster and the engine generated torque is smaller, even if the accelerator operation amount is constant.

For example, if the accelerator is released during acceleration,
The engine generated torque becomes smaller and the input torque to the input shaft 11 also becomes smaller. Along with that, loading cam 50
The pressing force of the power roller 23 that is generated by this is reduced. On the other hand, since the transmission has the transmission ratio changed to the high side,
The slip increases.

Here, if the pressing force is set to a small value for the purpose of improving the transmission efficiency in a steady state where the gear ratio is not changed, excessive slip occurs during gear shifting and the transmission efficiency deteriorates. On the contrary, if the pressing force is set to a large value in order to prevent the deterioration of the transmission efficiency, the transmission efficiency is unavoidably lowered in the steady state. And are in a trade-off relationship with each other.

However, in the device of the present invention, the throttle opening is corrected in accordance with the speed change speed, and in particular, a rapid decrease in the transmission torque between the input and output disks at the time of speed change is prevented, and the torque is smoothed. Therefore, by ensuring the generation of an appropriate pressing force, it is possible to perform power transmission with excellent transmission and transmission efficiency without the occurrence of excessive slip.

FIGS. 5 and 6 are graphs showing this, and FIGS. 5 (a), 5 (a) and 5 (c) show the transmission torque between the input and output disks, the tilt angle and the slip ratio in the prior art. 6 (a), 6 (b) and 6 (c) show the transmission torque, tilt angle and slip ratio of the device of the present invention, respectively.

According to these graphs, in the prior art,
Since the transmission torque sharply decreases due to the shift up in the vicinity of 10 seconds, the slip ratio in that portion sharply increases, and the power roller 23 shown by a broken line in the figure.
The actual tilting angle of is greatly delayed with respect to the command value shown by the solid line in the figure, whereas in the invention device, the decrease in the transmission torque between the input and output disks due to the shift up is slowed down. Compared with the technology, the amount of slip generation can be greatly reduced, and the power roller 2
It can be understood that the delay of the tilt angle of 3 with respect to the command value can be effectively removed.

Although the invention has been described based on the illustrated example, the auxiliary air amount, the ignition timing, the air-fuel ratio and the like can be controlled instead of controlling the throttle in order to control the transmission torque.

[0045]

As described above, according to the present invention, the pressing force of the power roller with respect to the input / output disk can always be made proper even during steady running with a constant gear ratio and during gear shifting. As a result, excellent transmission efficiency and transmission efficiency can be realized.

[Brief description of drawings]

FIG. 1 is a system diagram showing an embodiment of the present invention.

FIG. 2 is a control flowchart of the device shown in FIG.

FIG. 3 is a system diagram showing another embodiment of the present invention.

FIG. 4 is a control flowchart of the apparatus shown in FIG.

FIG. 5 is a graph showing a relationship among a transmission torque, a tilt angle, and a slip ratio in a conventional device.

FIG. 6 is a graph similar to FIG. 5 for the invented device.

[Explanation of symbols]

 10 Transmission Case 11 Input Shaft 12 Input Disc 13 Output Disc 14 Hollow Output Shaft 15 Output Gear 16,20 Thrust Bearing 17 Cylinder 18 Hydraulic Piston 19, 33, 34 Hydraulic Chamber 23 Power Roller 24 Tilting Shaft 27, 28 Tie Rod 29, 30 Joint 31, 32 Hydraulic Piston 35 Cam 36 Cam Disc 37 Follower Roller 40 Oil Pump 41, 42 Hydraulic Control Valve 43, 44 Control Signal 45 Control Unit 45a Shift Speed Calculation Means 45b Pressurization Control Signal Correction Means 45c Input Torque Calculation Means 45d Generated torque correction means 45e Gear ratio calculation means 46 Throttle opening signal 47 Vehicle speed signal 48 Accelerator operation amount signal 49 Throttle opening command signal 50 Loading cam

Claims (2)

[Claims] 1. Power transmission from an input disk to an output disk is performed via a power roller pressed against the opposing surfaces of both disks, and the pressing force of the power roller to the input / output disk is set to the input disk. A toroidal type continuously variable transmission that changes in accordance with an input torque to an input shaft to be coupled, wherein a speed change speed calculation means and a power roller pressing force is corrected based on the speed change speed obtained by the speed change speed calculation means. ,
A toroidal-type continuously variable transmission including a pressure control signal correction means for increasing the pressing force of a power roller as the speed of change increases. 2. Power transmission from an input disk to an output disk is performed via a power roller pressed against the opposing surfaces of both disks, and the pressing force of the power roller to the input / output disk is applied to the input disk. A toroidal-type continuously variable transmission that is interposed between an input shaft coupled to the engine and an engine, and is changed by a loading cam that operates in response to an input torque to the input shaft. And a torque generation means for correcting the engine-generated torque on the basis of each of the shift speed and the torque signal obtained by the respective means, and increasing the engine-generated torque as the shift speed increases. Toroidal type continuously variable transmission.