JP2601082B2 - Control device for continuously variable transmission - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

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

[0002]

2. Description of the Related Art In the case of a transmission in which a shift is controlled by using a signal from a vehicle speed sensor, if the vehicle speed sensor fails and no signal is output, it is determined that the vehicle speed is extremely low, and a sudden downshift is instructed. Will be. To prevent this, for example, Japanese Unexamined Patent Application Publication No. Sho 61-479445 discloses a technique in which a stepped automatic transmission is fixed to a gear at the time of failure. In addition, Japanese Unexamined Patent Publication No.
Japanese Patent Application Laid-Open No. 9-133855 discloses a configuration in which, when a downshift command is issued, the shift command is not output if the shift command is abnormal based on the engine rotation speed. .

[0003]

However, all of the above-mentioned techniques are intended only to prevent a sudden shift from occurring at the time when the vehicle speed sensor fails. Is not considered.
That is, for example, if a failure occurs while driving at the fourth speed,
Since the vehicle is fixed to the fourth speed, the vehicle cannot be started, and the vehicle cannot run for the time being to a place where a failure can be repaired. An object of the present invention is to solve such a problem.

[0004]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems by controlling the speed change based on the input shaft rotation speed at the time of occurrence of a failure. That is, as shown in FIG. 1, a control device for a continuously variable transmission according to the present invention includes a vehicle speed sensor failure detecting means for detecting a failure of a vehicle speed sensor, and an input shaft at that time when a failure of the vehicle speed sensor is detected. A failure target value setting means for setting the rotation speed to the target input shaft rotation speed, and a target input shaft rotation speed set by the failure target value setting means for the actual input shaft rotation speed detected by the input shaft rotation speed sensor And feedback control means for performing feedback control so as to coincide with

[0005]

When the vehicle speed sensor fails during traveling, the gear ratio is controlled so that the rotation speed of the input shaft at that time is maintained. Therefore, if the vehicle speed decreases, the gear ratio increases, while if the vehicle speed increases, the gear ratio decreases, and the vehicle can continue running without any problems. If the input shaft rotation speed at the time when the vehicle speed sensor failure occurs is too high, the fuel consumption increases or the noise increases, so an upper limit value is set for the target input rotation speed. If the input shaft rotation speed at the time of failure is too low, insufficient power performance or the like may occur, so a lower limit is provided for the target input rotation speed.

[0006]

FIG. 2 shows a power transmission mechanism of a continuously variable transmission. The continuously variable transmission includes a fluid coupling 12, a forward / reverse switching mechanism 15, a V-belt type continuously variable transmission mechanism 29, a differential gear 56.
And the like, so that the rotation of the output shaft 10a of the engine 10 can be transmitted to the output shafts 66 and 68 at a predetermined gear ratio and rotation direction. The continuously variable transmission includes a fluid coupling 12 (having a lock-up oil chamber 12a, a pump impeller 12b, a turbine runner 12c, a lock-up clutch 12d, etc.), a rotating shaft 13, a drive shaft 14, and a forward / reverse switching mechanism. 15, drive pulley 16 (fixed cone member 1)
8, drive pulley cylinder chamber 20 (chamber 20a, chamber 20
b), comprising a movable cone member 22, a groove 22a, etc.),
Planetary gear mechanism 17 (sun gear 19, pinion gear 21,
A pinion gear 23, a pinion carrier 25, an internal gear 27, etc.), a V-belt 24, a driven pulley 2
6 (fixed cone member 30, driven pulley cylinder chamber 32,
Driven cone 28, forward clutch 40, drive gear 46, idler gear 48, reverse brake 50, idler shaft 52, pinion gear 54,
Final gear 44, pinion gear 58, pinion gear 60, side gear 62, side gear 64, output shaft 66,
Although it is composed of the output shaft 68 and the like, a detailed description thereof will be omitted. The configuration of the parts not described is described in Japanese Patent Application Laid-Open No.
No. 5353.

FIGS. 3, 4, 5 and 6 show a hydraulic control device for a continuously variable transmission. This hydraulic control device includes an oil pump 10
1. Line pressure regulating valve 102, manual valve 104, shift control valve 106, regulating pressure switching valve 108, step motor 11
0, transmission operation mechanism 112, throttle valve 114, constant pressure regulating valve 116, solenoid valve 118, coupling pressure regulating valve 1
20, a lock-up control valve 122, etc., which are connected to each other as shown in the drawing. The forward clutch 40, the reverse brake 50, the fluid coupling 12, the lock-up oil chamber 12a, the drive pulley The cylinder chamber 20 and the driven pulley cylinder chamber 32 are also connected as shown. Detailed description of these valves and the like will be omitted. The parts for which the description has been omitted are described in the above-mentioned JP-A-61-105353. 3, 4 and 5 indicate the following members. Pinion gear 110a, tank 130, strainer 131, oil passage 132, relief valve 133, valve hole 134, port 13
4a-e, spool 136, land 136a-b, oil passage 138, one-way orifice 139, oil passage 140, oil passage 1
42, one-way orifice 143, valve hole 146, port 1
46a-g, spool 148, lands 148a-e, sleeve 150, spring 152, spring 154,
Transmission ratio transmission member 158, oil passage 164, oil passage 165, orifice 166, orifice 170, valve hole 172, ports 172a-e, spool 174, lands 174a-c,
Spring 175, oil passage 176, orifice 177, link 178, oil passage 179, pin 181, rod 182,
Lands 182a-b, rack 182c, pin 183, pin 185, valve hole 186, ports 186a-d, oil passage 18
8, oil passage 189, oil passage 190, valve hole 192, port 19
2a-g, spool 194, lands 194a-e, negative pressure diaphragm 198, orifice 199, orifice 2
02, orifice 203, valve hole 204, port 204a
-E, spool 206, lands 206a-b, spring 208, oil passage 209, filter 211, orifice 216, port 222, solenoid 224, plunger 224a, spring 225, valve hole 230, port 23
0a-e, spool 232, land 232a-b, spring 234, oil passage 235, orifice 236, valve hole 2
40, ports 240a-h, spool 242, land 2
42a-e, oil passage 243, oil passage 245, orifice 24
6, orifice 247, orifice 248, orifice 249, choke-type throttle valve 250, relief valve 25
1. Choke type throttle valve 252, pressure holding valve 253, oil passage 25
4, cooler 256, cooler pressure holding valve 258, orifice 2
59, changeover detection switch 298.

FIGS. 7, 8 and 9 show an electronic control unit 30 for controlling the operation of the step motor 110 and the solenoid 224.
Indicates 0. The electronic control unit 300 includes an input interface 311, a reference pulse generator 312, a CPU (central processing unit) 313, a ROM (read only memory) 314,
It has a RAM (random access memory) 315 and an output interface 316, which are connected by an address bus 319 and a data bus 320. The electronic control unit 300 includes an engine speed sensor 301, a vehicle speed sensor 302, a throttle opening sensor 303, a shift position switch 304, a turbine speed sensor 305 (input shaft speed sensor), an engine coolant temperature sensor 306, and a brake sensor. 307 and the signal from the changeover detection switch 298 are directly or by the waveform shapers 308, 309 and 322, and AD
Signals are input through the converter 310, while signals are output to the stepper motor 110 through the amplifier 317 and lines 317a-d, and also to the solenoid 224, but a detailed description thereof will be omitted. Incidentally, the configuration of the part whose description is omitted is described in
-105353.

The control relating to the failure of the vehicle speed sensor 302 is performed according to the flow shown in FIG. First, it is determined whether or not an abnormality has occurred in the vehicle speed sensor 302 (step 102). If there is no abnormality, normal shift control is performed (step 104). The actual input shaft rotation speed obtained by the turbine rotation speed sensor 305 at the time is set as the target input shaft rotation speed A (106). Next, it is determined whether the value of A is larger than a preset upper limit U (108). If A is smaller than U, it is determined whether A is smaller than a preset lower limit L. (Id. 110). If A is greater than L, ie A
Is between L and U, feedback control is performed such that A is the target input shaft rotation speed as it is and the actual input shaft rotation speed matches this (112). On the other hand, if the value of A is larger than U in step 108, the upper limit value U is set as the value of A (114), and the process proceeds to step 112. If A is smaller than L in step 110, L is set as the value of A (see 11).
6) Go to step 112. After all, if there is no abnormality in the vehicle speed sensor 302 by the above control, the shift control is performed based on the vehicle speed and the accelerator opening as usual, but if the vehicle speed sensor 302 fails,
This normal control is abandoned, and feedback control is performed with the input shaft rotation speed at the time of failure occurring as a target value. Therefore, the gear ratio is controlled so that the engine rotation speed is substantially constant, and the vehicle can smoothly run from starting to steady running. In addition, since the target input rotation speed does not change when a failure occurs in the vehicle speed sensor 302, abrupt gear shifting does not occur naturally. The upper limit U and the lower limit L are set for the following reason. For example, when the vehicle speed sensor 302 breaks down when the engine speed is high during rapid acceleration, running at the input shaft speed always increases fuel consumption, noise, and increases the engine coolant temperature. Also invite. Therefore, when the input shaft rotation speed is higher than a predetermined value, the upper limit value U
Is set as the target value. When the input shaft rotation speed is very low, such as immediately before stopping, the vehicle speed sensor 3
If a failure occurs in 02, the power performance may be insufficient at the input shaft rotational speed and sufficient traveling may not be performed. Therefore, the lower limit value L is set. Step 102 constitutes a vehicle speed sensor failure detecting means, step 106 constitutes a failure target value setting means, and step 112 constitutes a feedback control means.

[0010]

As described above, according to the present invention, even when the vehicle speed sensor fails, it is possible to continue running at the input shaft rotational speed at that time, and the shift is performed despite the occurrence of the failure. It can be done smoothly for the time being.

[Brief description of the drawings]

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

FIG. 2 is a skeleton diagram of a continuously variable transmission.

FIG. 3 is a diagram showing a left part of a hydraulic control device of the continuously variable transmission.

FIG. 4 is a diagram showing a central portion of a hydraulic control device of the continuously variable transmission.

FIG. 5 is a diagram showing a right part of a hydraulic control device of the continuously variable transmission.

FIG. 6 is a diagram showing an arrangement relationship of FIGS. 3, 4, and 5;

FIG. 7 is a diagram illustrating a left portion of the electronic control device.

FIG. 8 is a diagram showing a right portion of the electronic control device.

FIG. 9 is a diagram showing an arrangement relationship between FIGS. 7 and 8;

FIG. 10 is a diagram showing a control flow.

[Description of Signs] 300 Electronic control unit 302 Vehicle speed sensor 305 Turbine rotation speed sensor (input shaft rotation speed sensor)

Claims (2)

(57) [Claims] 1. A control device for a continuously variable transmission configured to control a gear ratio based on signals from a plurality of sensors, wherein one vehicle speed sensor and an input shaft rotation speed sensor are used as the plurality of sensors. A vehicle speed sensor failure detecting means for detecting a failure of a vehicle speed sensor; and a failure target value setting for setting an input shaft rotation speed at that time to a target input shaft rotation speed when a failure of the vehicle speed sensor is detected. And feedback control means for performing feedback control so that the actual input shaft rotation speed detected by the input shaft rotation speed sensor matches the target input shaft rotation speed set by the failure target value setting means. A control device for a continuously variable transmission. 2. The failure target value setting means sets an upper limit value as a target input shaft rotation speed when an actual input shaft rotation speed at the time of failure is equal to or higher than a preset upper limit value. The control device for a continuously variable transmission according to claim 1, wherein the lower limit value is set as the target input shaft rotation speed when the actual input shaft rotation speed at the time of occurrence is equal to or lower than a preset lower limit value.