JPH06257662A - Speed change controller of frictional wheel type continuously variable transmission - Google Patents

Abstract

PURPOSE:To prevent generation of slippage during speed change transient time by decreasing transmission speed as a working oil temperature becomes higher when the working oil temperature of a frictional wheel type continuously variable transmission is higher than a specified value. CONSTITUTION:A standard transmission speed is read from a standard transmission speed setting device 16, and is set. Next, a working oil temperature is read from a working oil temperature detection device 20. The working oil temperature is compared with the standard value of the working oil temperature. Driving speed of a step motor 412 corresponding to the working oil temperature is retrieved when the working oil temperature is higher than the standard value of the working oil temperature. Then the driving speed of the step motor 412 is reset to the retrieved value. Thereafter, the step motor 412 is driven at the reset driving speed, and then the speeds of first and second continuously variable transmission mechanisms 22, 24 are changed. Consequently, a quantity of side slippage during transmission transient time can be decreased since the driving speed of the step motor 412 is made small namely the transmission speed can be decreased to such an extent as the working oil temperature becomes larger than the standard value.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a shift control device for a friction wheel type continuously variable transmission.

[0002]

2. Description of the Related Art The following is a conventional shift control device for a continuously variable transmission. For example, JP-A-62-286
What is disclosed in Japanese Patent No. 847 is continuously variable when the temperature of hydraulic oil of a V-belt type continuously variable transmission exceeds a predetermined temperature or when the temperature of cooling water for cooling an internal combustion engine exceeds a predetermined temperature. Change the gear ratio of the transmission to a smaller side (high side). This prevents the reduction of the power transmission capacity due to the rise of the temperature of the hydraulic oil.

[0003]

In the above-described conventional shift control device, the input rotation is reduced at the same vehicle speed by restricting the gear ratio so as not to be on the large side (low side), so that slip is unlikely to occur. In addition, the amount of heat generation also decreases due to the decrease in rotation speed. However, in the case of the friction wheel type continuously variable transmission, side slip occurs due to the tilting of the friction roller, and this increases as the shift speed increases, as shown in FIG. As the amount of side slip increases, the component of the traction coefficient in the side slip direction increases, as shown in FIG. 8, and the component in the power transmission direction orthogonal to this component decreases. Originally, as shown in FIG. 9, the traction coefficient decreases as the temperature of the hydraulic oil rises.
Therefore, when the gear is rapidly changed in a state where the temperature of the hydraulic oil is high (even if the gear ratio is not set to a predetermined value or higher), the traction coefficient is significantly reduced, and slip occurs. The present invention is intended to solve such a problem.

[0004]

SUMMARY OF THE INVENTION According to the present invention, when the working oil temperature of the friction wheel type continuously variable transmission is higher than a predetermined value, the higher the working oil temperature is, the lower the shift speed is. To solve. That is, the shift control device for a friction wheel type continuously variable transmission according to the present invention is provided with an input disc, an output disc, and a friction arranged in a toroidal groove formed by the discs so as to make frictional contact with both discs. A roller and a roller support member that rotatably supports the friction roller via an eccentric shaft, and that is rotatable about a rotary shaft portion orthogonal to the shaft centers of both discs and is movable in the axial direction of the rotary shaft portion. And a actuator capable of driving the roller support member in the axial direction of the rotating shaft portion, the shift control device sets a target input rotation speed based on operating conditions, as shown in FIG. Input rotation speed setting means, reference shift speed setting means for setting a reference shift speed based on the target input rotation speed, and temperature of hydraulic oil of the friction wheel type continuously variable transmission can be detected. And the dynamic oil temperature detecting means, when the working oil temperature is below a predetermined value and drives the actuator so speed shifting speed of the reference is performed,
When the operating oil temperature is higher than a predetermined value, the operating speed of the actuator is changed so that the higher the operating oil temperature is, the lower the speed change speed than the reference speed change speed is. And

[0005]

The temperature of the hydraulic oil of the friction wheel type continuously variable transmission is detected by the hydraulic oil temperature detecting means, and when the hydraulic oil temperature is below a predetermined value, it is set by the shift speed limiting means by the reference shift speed setting means. The actuator is driven so that the gear shift is performed at the reference gear shift speed, and when the hydraulic oil temperature is equal to or higher than the predetermined value, the gear shift is performed at the gear shift speed lower than the reference gear shift speed as the temperature of the hydraulic oil increases. Drive the actuator. As a result, it is possible to reduce the amount of side slip during a gear shift transition.

[0006]

FIG. 2 shows a friction wheel type continuously variable transmission 16 as a frame diagram. The input shaft 16a of the friction wheel type continuously variable transmission 16 is connected to the forward / reverse switching mechanism 15. Forward / reverse switching mechanism 1
5 includes a planetary gear mechanism 17, a forward clutch 40, and a reverse brake 50. The planetary gear mechanism 17 includes a sun gear 19, a pinion carrier 25 having two pinion gears 21 and 23, and an internal gear 27. The pinion gears 21 and 23 having the same diameter are in mesh with each other, the pinion gear 21 is in mesh with the internal gear 27, and the pinion gear 23 is in mesh with the sun gear 19. The sun gear 19 is always connected so as to rotate integrally with the input shaft 16a. The pinion carrier 25 can be connected to the input shaft 16a by the forward clutch 40. Further, the internal gear 27 can be fixed to the casing 11 by the reverse brake 50. The pinion carrier 25 is always connected to the transmission shaft 37 to the continuously variable transmission mechanism. A first continuously variable transmission mechanism 22 and a second continuously variable transmission mechanism 24 are provided on the downstream side of the forward / reverse switching mechanism 15 in the casing 11. The first continuously variable transmission mechanism 22 includes an input disk 26 and an output disk 28.
And a pair of friction rollers 30 for transmitting the rotational force therebetween. Input disk 26 and output disk 28
The contact surface with the friction roller 30 is a toroidal surface.
By changing the contact state of the friction roller 30 with the input disk 26 and the output disk 28, the rotation speed ratio between the input disk 26 and the output disk 28 can be continuously changed. The second continuously variable transmission mechanism 24 also has an input disc 32, an output disc 34, and a pair of friction rollers 36, which are similar to those of the first continuously variable transmission mechanism 22. However, the arrangement of the input disk 32 and the output disk 34 is
It is opposite to the first continuously variable transmission mechanism 22. That is, the output disc 28 and the output disc 34 are arranged so as to be adjacent to each other. The input disk 26 is supported via a ball spline 61 on the outer circumference of an input shaft 38 which is connected to the transmission shaft 37 so as to rotate integrally therewith.
A cam flange 42 is arranged on the back side of the input disk 26. A cam roller 46 is provided on the cam surfaces of the cam flange 42 and the input disk 26 facing each other. The cam roller 46 is shaped so as to generate a force that presses the input disk 26 toward the output disk 28 when the input disk 26 and the cam flange 42 rotate relative to each other. The cam flange 42, the input disc 26, and the cam roller 46 form a loading cam 63. The input disk 32 of the second continuously variable transmission 24 is also connected to the input shaft 38 via a ball spline 65.
The input disk 32 is constantly subjected to a force toward the output disk 34 by the disc spring 51. The output disc 28 of the first continuously variable transmission mechanism 22 and the output disc 34 of the second continuously variable transmission mechanism 24 are rotatably supported on the input shaft 38, respectively. A drive gear 55 is provided so as to rotate integrally with the output disc 28 and the output disc 34. The drive gear 55 meshes with a driven gear 60 that is coupled to one end of an intermediate shaft 59 arranged parallel to the input shaft 38 so as to rotate integrally therewith. The gear 67 integrally formed on the other end side of the intermediate shaft 59 is connected to the output shaft 16 via an idler gear 69.
It meshes with a gear 71 that is integral with b.

FIG. 3 shows a sectional view of a portion of the first continuously variable transmission mechanism 22 (note that the basic structure of the second continuously variable transmission mechanism 24 is the same as that of the first continuously variable transmission mechanism 22 shown in FIG. 2). Is the same as). The roller support member 83 includes the upper and lower rotating shaft portions 83.
The spherical bearings 110 and 112 are supported by a and 83b so as to be rotatable and vertically movable.
The above-mentioned friction roller 30 is rotatably supported by the roller support member 83 via an eccentric shaft 84. Spherical bearing 1
10 is supported by a link 114, and this link 11
4 is supported by a link post 116 fixed to the casing 11. The spherical bearing 112 is also supported by the link 118, and the link 118 is supported by the link post 120. Roller support member 8
3 is an extension shaft portion 83 provided concentrically with the rotation shaft portion 83b.
have c. The extension shaft portion 83c is the rotation shaft portion 83.
It is configured to rotate integrally with b. Extension shaft 8
A piston 124 is provided on the outer circumference of 3c. The piston 124 is inserted into a piston insertion hole 304 formed in a main cylinder body 302a attached to the casing 11 with a bolt 300. A sub-cylinder body 302b, which is fastened together with the above-described bolt 300 via a separate plate 306, is attached to the lower surface of the main cylinder body 302a.
Is configured. As a result, oil chambers 128 and 130 are formed above and below the piston 124 (note that the oil chamber 128 and the oil chamber 130 are upside down on the right side and the left side in the drawing), and the hydraulic pressure acting on them forms the oil chambers. Piston 12
4 can move up and down. A hydraulic cylinder device is configured by the piston 124 and the piston insertion hole 304 of the main cylinder body 302a. A valve body 310 is arranged below the cylinder body 302. The valve body 310 is composed of a main valve body 310a and a sub valve body 310b attached to the upper surface of the main valve body 310a via a separate plate 311. Main valve body 3
A shift control valve 410 is provided at 10a. The shift control valve 410 is provided with a step motor 412 (actuator) that is rotationally driven according to a commanded gear ratio and teeth that mesh with a pinion 412a that is driven by the step motor 412, and that is axially driven by the rotation of the step motor 412. Spool with rack that can be moved to 41
4 and one end thereof is connected to the spool 414 with the rack, and the spool 41 is movable in the axial direction together with the spool 414 with the rack by the rotation of the step motor 412.
6 and a sleeve 41 provided on the outer circumference of the spool 416
8, a spring 419 that presses the sleeve 418 to the left in the drawing, and a retainer 420 that is fitted to the outer end of the sleeve 418. Main valve body 310
An oil passage 422 and an oil passage 424 are provided in a. The oil passage 422 is connected to the oil chamber 128. The oil passage 424 is connected to the oil chamber 130. In the oil passage 422 and the oil passage 424, the line pressure of the oil passage 423 is used as a hydraulic pressure source, and the spool 4
The hydraulic pressure is distributed according to the relative positional relationship between 16 and the sleeve 418. That is, the relationship between the land of the spool 416 and the oil groove of the sleeve 418 is that the oil pressures in the oil passage 422 and the oil passage 424 are equal in the reference state shown in FIG. 2, and when the spool 416 moves relatively to the left. In order to make the oil pressure of the oil passage 424 higher than the oil pressure of the oil passage 422, and when the spool 416 relatively moves to the right, the oil passage 42
4 is set to be lower than the oil pressure of the oil passage 422. A cam 320 that is rotatable integrally with the extension shaft portion 83c is provided at the lower end of the extension shaft portion 83c. The cam 320 has an inclined surface, and the link 322 is in contact with this. As a result, when the cam 320 rotates, the link 322 swings, and the tip of the link 322 can press the retainer 420.

FIG. 4 is a block diagram showing an apparatus for controlling the operation of the step motor 412. The throttle opening detected by the throttle opening detection device 10 and the vehicle speed detected by the vehicle speed detection device 12 are input to the control target input rotation speed setting device 14 (control target input rotation speed setting means). In the control target input rotation speed setting device 14, the target input rotation speed is set based on the input value, and this is input to the reference shift speed setting device 16 (reference shift speed setting means). The reference shift speed setting device 16 sets a reference shift speed based on the target input rotation speed, and inputs this to the shift speed limiting device 18 (shift speed limiting means). The shift speed limiting device 18 includes a hydraulic oil temperature detecting device 2
The hydraulic oil temperature T detected by 0 (operating oil temperature detecting means) is also input. The hydraulic oil temperature detection device 20 is arranged to detect the temperature of the cooling oil of the friction wheel type friction wheel type continuously variable transmission 16. As shown in FIG. 5, the shift speed limiting device 18 is preset with the hydraulic oil temperature and the corresponding drive speed of the step motor 412. The driving speed of the step motor 412 is constant until the hydraulic oil temperature T reaches the reference value T0, and the hydraulic oil temperature T is the reference value T0.
When set to the above, the hydraulic oil temperature T is set to decrease as it increases. Shift speed limiting device 18
Sets the drive speed of the step motor 412 based on the hydraulic oil temperature T input from the hydraulic oil temperature detection device 20, and inputs this to the step motor 412. The step motor 412 is driven based on the input drive speed to operate the first continuously variable transmission mechanism 22 and the second continuously variable transmission mechanism 24.

FIG. 6 shows a control flow of the speed change speed limiting device 18.
Shown in. First, the reference shift speed is read from the reference shift speed setting device 16 and set (step 102). Then
The hydraulic oil temperature T is read from the hydraulic oil temperature detection device 20 (step 104). Then, T is compared with the reference value T0 of the hydraulic oil temperature (106). If T is greater than T0, then T
The drive speed of the step motor 412 corresponding to is searched (108). Next, the drive speed of the step motor 412 is reset to the retrieved value (at step 110). After that, the step motor 412 is driven at the reset drive speed,
The continuously variable transmission mechanisms 22 and 24 are shifted. If T is smaller than T0 in step 106, the step motor 4 is directly driven at the drive speed corresponding to the reference shift speed.
Drive twelve. As a result, the hydraulic oil temperature T becomes the reference value T
Since the driving speed of the step motor 412 can be decreased, that is, the shift speed can be reduced as the value is greater than 0, the amount of side slip during the shift transition can be reduced. Therefore, it is possible to prevent a decrease in the traction coefficient in the power transmission direction and suppress the occurrence of slip.

[0010]

According to the present invention, when the working oil temperature of the friction wheel type continuously variable transmission is higher than a predetermined value, the higher the working oil temperature is, the lower the shift speed is. Can be prevented.

[Brief description of drawings]

FIG. 1 is a diagram showing relationships between components of the present invention.

FIG. 2 is a skeleton diagram of a friction wheel type continuously variable transmission.

FIG. 3 is a partial cross-sectional view of a first continuously variable transmission.

FIG. 4 is a block diagram of a shift control device according to the present invention.

FIG. 5 is a diagram showing a relationship between a hydraulic oil temperature and a driving speed of a step motor.

FIG. 6 is a control flow of the embodiment.

FIG. 7 is a diagram showing a relationship between a shift speed and a side slip amount.

FIG. 8 is a diagram showing a relationship between a side slip amount and a traction coefficient in a power transmission direction.

FIG. 9 is a diagram showing a relationship between a hydraulic oil temperature and a traction coefficient.

[Explanation of symbols]

14 Control Target Input Rotational Speed Setting Device (Control Target Input Rotational Speed Setting Means) 16 Reference Shift Speed Setting Device (Reference Shifting Speed Setting Means) 18 Shift Speed Limiting Device (Shifting Speed Limiting Means) 20 Hydraulic Oil Temperature Detection Device (Operating Oil Temperature detecting means) 22 first continuously variable transmission mechanism 24 second second continuously variable transmission mechanism 26, 32 input disc 28, 34 output disc 30, 36 friction roller 83 roller support member 83b rotating shaft portion 84 eccentric shaft 412 step motor (actuator)

Claims (1)

[Claims] 1. An input disk, an output disk, a friction roller arranged to make frictional contact with both disks in a toroidal groove formed by both disks, and the friction roller is rotatable via an eccentric shaft. And a roller support member that is rotatable around a rotary shaft portion that is orthogonal to the shaft centers of both discs and is movable in the axial direction of the rotary shaft portion, and the roller support member in the axial direction of the rotary shaft portion. In a shift control device for a friction wheel type continuously variable transmission having a drivable actuator, the shift control device comprises a control target input rotation speed setting means for setting a target input rotation speed based on operating conditions, and the target input Reference shift speed setting means for setting a reference shift speed based on the rotation speed, hydraulic oil temperature detecting means capable of detecting the temperature of the hydraulic oil of the friction wheel type continuously variable transmission, and When the temperature is lower than a predetermined value, the actuator is driven so that the gear shift is performed at the above-mentioned reference speed, and when the temperature of the hydraulic oil is higher than the predetermined value, the higher the temperature of the hydraulic oil, the lower the speed than the above-mentioned reference speed. A shift control device for a friction wheel type continuously variable transmission, comprising: a shift speed limiting unit that drives an actuator so that a shift is performed at the above shift speed.