JPS62177343A - Device for controlling automatic transmisson - Google Patents

Abstract

PURPOSE:To prevent the burning, etc. of a friction clamping element by providing a failure detecting means for a solenoid driving circuit and a speed change forbidding means for speed changing by means of clamping and releasing of said friction element when failure is detected. CONSTITUTION:A control device 34 has a microcomputer and a memory, signals from various sensors are inputted in it to undergo arithmetic processing, and timing, 1-2, 2-3, and 3-4 solenoids 37, 28, 30, 32 are turned on and off by its output signals. The timing solenoid 37, a transistor, and a CPU are connected to the control device 34 to give the output signal of the CPU to the control device 34, while providing a failure detecting means for checking a monitor signal to detect a failure, together with other failure detecting means for other solenoids. Accordingly, when a solenoid fails, a speed change the timing of which is adjusted by this solenoid is prevented from being carried out, to prevent the burning of a friction clamping element.

Description

[Detailed description of the invention] (b) Industrial application field The present invention relates to a control device for an automatic transmission.

(b) Conventional technology Automatic transmissions change gears by switching the operating state of frictional engagement elements from tlff to tlff. When changing gears, for example, one frictional engagement element is engaged while the other frictional engagement element is released. In order to perform a smooth gear shift, it is necessary to engage and release the two frictional engagement elements at predetermined timings. For this reason, the supply and discharge of hydraulic pressure to the friction-fastening element T5 is controlled by a hydraulic throttle device such as an orifice. However, depending on the operating conditions, it is necessary to prevent the orifice from causing a throttling effect. For this reason, a bypass oil passage is provided in the orifice, and this bypass oil passage is configured to be opened and closed by a timing valve.

The timing valve is switched depending on vehicle speed, throttle opening, etc. Such a device is used, for example, in [Nirasan Automatic Transaxle Maintenance Manual (FOZA
41-
It is described on page 42.

(c) Problems to be solved by the invention However, when the timing valve is controlled by a solenoid that is turned on and off according to the vehicle speed signal, throttle opening signal, etc., the following problems occur. do. That is, if the solenoid drive circuit fails, the bypass oil passage will remain blocked or remain in communication. In this case, since the supply and discharge of hydraulic pressure is not controlled at a predetermined timing, the engagement or disengagement of the friction engagement element may be delayed or early, resulting in burnout of the friction engagement element. In particular, if a failure occurs while the bypass oil passage is blocked, the rise of the oil pressure is delayed and the above-mentioned problems are likely to occur. The present invention aims to solve these problems.

(d) Means for Solving the Problems The present invention provides a method for preventing gear shifting whose timing is controlled by the solenoid drive circuit that controls the gear shifting timing from occurring when a failure occurs in the solenoid drive circuit that controls the shifting timing.
Solve the above problems.

That is, as shown in FIG. 1, the automatic transmission control device according to the present invention includes a failure detection means for detecting a failure of the solenoid drive circuit, and a failure detection means that detects failure of the solenoid drive circuit. and a speed change prohibiting means for prohibiting a speed change achieved by engaging or releasing the marking element.

(e) When a failure occurs in the operating solenoid drive circuit, this is detected by the failure detection means. When the fault detection means detects a fault, the shift inhibiting means inhibits the associated shift of the wear element whose timing is adjusted by the hydraulic throttling device. As a result, clutches due to delays in oil pressure start-up, etc.
Brake burnout is prevented.

(F) Embodiments Hereinafter, embodiments of the present invention will be described with reference to FIGS. 2 to 8 of the accompanying drawings.

FIG. 2 shows a schematic diagram of a power transmission mechanism of an automatic transmission with four forward speeds and one reverse speed with an overdrive. This power transmission mechanism consists of a human power shaft I to which rotational force from the engine output ME is transmitted via a torque converter T/C, an output shaft 0 which transmits driving force to the final drive device, a first planetary gear set G1, and a second planetary gear set G1. Gear set G2, first clutch c1, second
Clutch C2, third clutch C3, first brake Bl,
, J2 brake B2. and a one-way clutch OWC. The first planetary gear set G1 includes a sun gear S1,
It is composed of an internal gear R1 and a carrier PC1 that supports a pinion gear P1 that meshes with both gears S1 and R1 at the same time, and a planetary gear set G2 includes a sun gear s2, an internal gear R2, both gears 32 and R2.
It is composed of a carrier PC2 that supports a pinion gear P2 that meshes with the carrier PC2 at the same time. The carrier PC1 can be connected to the input shaft (2) via the clutch C2, and the sun gear S1 can be connected to the human power shaft (2) via the clutch C1. Carrier PC1 can also be connected to internal gear R2 via clutch C3. Sungear S2 is based on human power! is always connected to internal gear R1.
And the carrier PC2 is always connected to the output shaft 0.

Brake B1 can fix carrier PCI, and brake B2 can fix sun gear S1. The one-way clutch OWC has a structure that allows forward rotation (rotation in the same direction as the engine output shaft E) of the carrier Pct, but does not allow reverse rotation (rotation in the opposite direction to the forward rotation) (i.e., a structure that acts as a brake only during reverse rotation). It's Toshide.

The above power transmission mechanism operates the planetary gear set G by operating clutches c1, C2 and C3, brake Bl (one-way clutch 0WC) and B2 in various combinations.
1 and each element of G2 (St, B2, R1, R2, PC1
, and PC2), thereby making it possible to vary the rotational speed of the output IrIIIO with respect to the rotational speed of the human-powered shaft. Clutch C1, C2
By operating the brakes 81 and B2 in combination as shown in the table below, four forward speeds and one reverse speed can be obtained.

In addition, the 0 mark in the above table indicates the clutch and brake that are in operation, and α1 and α2 are internal gear R1, respectively.
The gear ratio is the ratio of the number of teeth of sun gears S1 and B2 to the number of teeth of R2, and the gear ratio is the ratio of the number of rotations of the human power shaft (2) to the number of rotations of the output 1lillIO. Also, (OWC) is displayed under B1, which means that even when brake B1 is not activated, one-way clutch OWC is used to
This shows that speed can be obtained. However, in the first speed in this case, it is not possible to drive from the output @0 side (that is, the engine brake does not work).

The brake B2 is constituted by a band brake, and its operation is controlled by a hydraulic servo device. The hydraulic servo system consists of a servo apply chamber S/A that applies hydraulic pressure in the direction of brake engagement, and a servo release chamber S/R that applies hydraulic pressure in the direction of brake release (the pressure receiving area of the servo release chamber S/R is (larger than the pressure receiving area of the chamber S/A).

Therefore, when hydraulic pressure is supplied to the servo apply chamber S/A, the brake B2 is engaged, but the servo release chamber S/R
If hydraulic pressure is also supplied to the brake B2, the brake B2 is released.

FIG. 3 shows a hydraulic control device that controls the supply of hydraulic pressure to the friction elements. Note that FIG. 3 shows only the basic parts of the hydraulic circuit, and the illustration of parts other than those related to the present invention is omitted. That is, the clutch C1 operates only when reversing, and the brake B1 also operates only when reversing and in the I range, so they are not shown because they are unrelated to the automatic shift in the D range.

Regarding the overall configuration of the hydraulic circuit which is not directly related to the present invention, for example, see Japanese Patent Application No. 1983 filed by the present applicant.
It is similar to that described in No.-222436.

Line pressure discharged by the oil pump IO and regulated by a regulator valve (not shown) is supplied to the oil passage 14 via the manual valve 12 in the case of a circuit range. The oil pressure in the oil passage 14 is controlled by the 1-2 shift valve 16 to be supplied to the oil passage 18, and the oil pressure in the oil passage 18 is controlled to be supplied to the oil passage 22 by the 2-3 shift valve 20. Further, the supply of the oil pressure of the oil passage 4 to the oil passage 26 is controlled by the 3-4 shift valve 24. The oil passage 22 is connected to the clutch C2, and the oil passage 18 is connected to the servo apply chamber S/A. Further, the oil passage 26 is connected to the clutch C3, or is provided with a one-sided orifice 31 (hydraulic throttle device) in the middle thereof. Also, a bypass oil passage 33 is provided that bypasses this one-way orifice, and this bypass oil passage 33 is connected to the timing valve 3.
5 (oil passage opening/closing device). Timing valve switching is done by timing solenoid 3
7. That is, when the timing solenoid 37 is off, the bypass oil passage 33 is communicated, and when it is on, it is cut off.

Further, the downstream side (
The side near the clutch C3) has an oil passage 27 connected to the servo release chamber S/R and the servo release timing valve 2.
Communication is possible via 9.

The servo release timing valve 29 is configured to connect the oil passage 26 and the oil passage 27 when hydraulic pressure is applied to the oil passage 22. 1-2 shift valve 16.2-3 shift valve 20 and 3-4 shift valve 24 are respectively 1-2 solenoid 28.2-3 solenoid 30.3-4
It is configured to be switched by a solenoid 32, and each solenoid and valve are configured to allow an oil passage to communicate when the solenoid is off, and to shut off the oil passage when the solenoid is on.

1-2 Solenoid 28. 2-3 Solenoid 30 and 3-
The operation of the four solenoid 32 is controlled by a signal from a control device 34 as shown in FIG. The control device 34 receives signals from a vehicle speed sensor 36, a throttle opening sensor 38, a select position switch 40, an idle switch (not shown), an engine oil temperature sensor, a pattern selection switch, etc. 34 turns on and off the timing solenoid 37.1-2 solenoid 28.2-3 solenoid 30 and 3-4 solenoid 32. The control device 34 includes a microcomputer (MPU), storage devices (RAM and ROM), and the like. 1-2 solenoid 28, 2-3 solenoid 30 and 3-4 solenoid 32 operate in combination as shown in FIG. As a result, hydraulic pressure is supplied to each of the predetermined rubbing elements as shown in the combinations in the table above, and the first, second, third and fourth speeds are achieved.

The control device 34 is provided with failure detection means for detecting a failure in the drive circuit of the timing solenoid 37 as shown in FIG. Timing solenoid 37 as shown
, a transistor, and a CPU are connected, and a failure is detected by giving an output signal from the CPU and checking a monitor signal. The routine is shown in FIG. First, if the output signal is on, it is determined whether the output signal and the monitor signal do not match, and if they match, it is determined that the timing solenoid 37 is in the off state and is malfunctioning, and the output signal is turned off. In this case, it is determined whether the output signal and the monitor signal do not match, and if they match, it is determined that the timing solenoid 37 is on and there is a failure. If the output signal and the monitor signal do not match whether the output signal is on or off, it is determined that the timing solenoid 37 is not malfunctioning.

The occurrence of a failure is checked for the timing solenoid 37 as described above, and if a failure is detected, the timing solenoid 37 is
Shifting is limited by the control flow shown in the figure. First, it is determined whether or not the timing solenoid 37 is in the ON state and has failed (Step 102). If it is not a failure, another control routine 200 is executed as is, and in the case of a failure, it is determined whether the fourth gear is on. 104), prohibiting the state from being in 4th gear if it is not in 4th gear (
106). In addition, in the case of 4th gear, the vehicle speed is 5km/h.
10B), 5km/h
In the above case, the vehicle is fixed at the fourth speed state (step 110). Also, if the speed is lower than 5 km/h, fourth gear is prohibited (4106). As a result, if, for example, the timing solenoid 37 fails while running in 4th gear, the vehicle will continue to run in 4th gear, and the vehicle will stop.
After h L, automatic gear shifting between 1st, 2nd and 3rd speeds will be performed, and there will be no risk of burnout of brake B2. Further, if the timing solenoid 37 is turned on and malfunctions while the vehicle is running in the 1st, 2nd or 3rd speed, the 4th speed is prohibited, and thus burnout of the brake B2 is similarly prevented.

Therefore, even if the timing solenoid 37 fails while it is in the ON state, it is possible to run the vehicle without the fourth speed. (In addition,
If the timing solenoid 37 is turned on and the 4-3 gear shift is performed with a failure, the brake B2 will burn out for the following reason.

That is, in this case, since the bypass oil passage 33 is blocked, the oil pressure of the oil passage 26 is always supplied via the one-way orifice 3, and the clutch 03 and brake B
The rise of the oil pressure in the servo release chamber S/R (No. 2) is delayed.

For this reason, the third speed is reached before the brake B2 is sufficiently released, causing friction in the brake B2 for a long time and generating a large amount of heat. This causes brake B2 to burn out. (G) As described in detail, according to the present invention, when a failure occurs in the solenoid that controls the opening and closing of the oil passage that bypasses the hydraulic throttle device, this solenoid adjusts the timing to: Since the gear change is not performed, it is possible to prevent burnout of the frictional engagement element.

[Brief explanation of drawings]

Fig. 1 is a diagram showing the relationship between the constituent elements of the present invention, Fig. 2 is a skeleton diagram of the automatic transmission, Fig. 3 is a diagram showing the hydraulic circuit, and Fig. 4 is a diagram showing the relationship between the components of the present invention.
5 shows the relationship between the combination of solenoid operations and gears, FIG. 6 shows the failure detection means, and FIG. 7 shows the control flow for failure detection. 8th
The figure is a diagram showing the control flow of the present invention. 31... One-way orifice (hydraulic throttle device), 33...
...Bypass oil passage, 35...Timing valve (oil passage opening/closing device), 37...Solenoid.

Claims (1)

[Claims] A hydraulic throttle device provided in the middle of an oil path connected to a friction element, a bypass oil path that bypasses the hydraulic throttle device,
A control device for an automatic transmission comprising an oil passage opening/closing device provided in a bypass oil passage and a solenoid for controlling opening/closing of the oil passage opening/closing device, a failure detection means for detecting a failure of the solenoid drive circuit; A control device for an automatic transmission, comprising: a shift prohibiting means for inhibiting a shift realized by engaging or disengaging the friction element when a failure detection means detects that a drive circuit has failed.