JPH03213769A - Automatic transmission for vehicle - Google Patents

Abstract

PURPOSE:To detect abnormality of a frictional engagement device early by setting the rotating speed of an output member of a hydrodynamic gearing at the time of cancelling the frictional engagement device as reference rotating speed, and comparing the detected rotating speed to the reference rotating speed under the neutral range selected condition to judge abnormality. CONSTITUTION:An A/T control device 30 compares the rotating speed of an output shaft of a torque converter to be detected by a sensor 34 to the reference rotating speed of the case that each frictional engagement device is normally cancelled, under the condition that a neutral range of an automatic transmission 14 is selected by a selecting means, namely, under the condition that each frictional engagement device is cancelled, to judge abnormality. Namely, when the frictional engagement device is cancelled normally, the rotating speed of the output shaft and the reference rotating speed coincide with each other, but when drag of the frictional engagement device or the like is generated by peeling of the friction member or oil leakage, the real rotating speed of the output shaft becomes too low against the reference rotating speed at the time of stopping a vehicle, and it becomes too high or too low at the time coasting travelling in response to the speed, and judgement of abnormality is thus possible. Abnormality can be detected even at the time of usual use of a vehicle.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to automatic transmissions for vehicles, and more particularly to a technique for detecting whether or not there is an abnormality in a frictional engagement device of the automatic transmission.

Conventional technology 1. Automobile automatic transmissions generally include a hydraulic transmission device such as a torque converter and a transmission mechanism such as an idling gear, and transmit output from the engine to the transmission mechanism via the hydraulic transmission device. At the same time, the transmission ratio is changed by the transmission mechanism. The transmission mechanism is provided with several frictional engagement devices, and by changing the operating state of the frictional engagement devices, the gear ratio and forward movement can be changed.

I can't move backwards/) I'm stuck. The automatic transmission described in Japanese Patent Application Laid-Open No. 1-238736 is an example of such an automatic transmission, which uses a planetary gear device to reduce the gear ratio in stages.

Problems to be Solved by the Invention By the way, in such automatic transmissions for vehicles, if the friction engagement device is repeatedly engaged due to sudden starts or sudden acceleration, the friction plates, brake tram, etc. There is a risk that the friction material will wear out and problems such as peeling and seizure may occur. If the drag force at release increases due to such peeling or seizure, the wear of the friction material will further accelerate, causing problems such as shortening the life of the friction engagement device. . In addition, the pull when releasing the above is as follows:
It can also occur due to leakage of hydraulic oil that operates the frictional engagement device.

The present invention has been made against the background of the above-mentioned circumstances, and its purpose is to enable prompt detection of abnormalities in the above-mentioned frictional engagement device during normal use of the vehicle.

Means for Solving the Problem In order to achieve this objective, the magnitude of the drag (load torque) when the frictional engagement device is released is determined from the rotational speed of the output member of the hydrodynamic transmission device. Preferably, in the present invention, the engine output is transmitted through the hydrodynamic transmission device, and the forward or reverse range is selected by the selection means, so that the frictional engagement device is engaged and the rotation of the engine is controlled. An automatic transmission for a vehicle that changes gears at a predetermined gear ratio while at the same time selecting a neutral range by the selection means, releases the frictional engagement device and cuts off the output of the engine, a
) selection detection means for detecting that the neutral range has been selected by the selection means; (b) rotation speed detection means for detecting the rotation speed of the output member of the hydrodynamic transmission;
) The rotational speed of the output member of the hydrodynamic transmission device when the frictional engagement device is normally released is set as the reference rotational speed, and the selection detection means detects that the neutral range is selected. The engine is characterized by further comprising a determining means for determining whether or not the rotational speed detected by the rotational speed detection means is abnormal by comparing it with the reference rotational speed in the state in which the rotational speed is abnormal.

Here, the above-mentioned neutral range does not necessarily mean that all frictional engagement devices of the automatic transmission are in a released state, but at least some of the frictional engagement devices are released and the transmission of engine output is cut off. It would be good if it could be done.

Furthermore, the rotation speed detection means does not necessarily need to detect the rotation speed of the output member itself of the hydrodynamic transmission device, but rather the rotation speed of another member that rotates integrally with the output member or rotates in a fixed relationship. It may be something that detects numbers.

Furthermore, even if the reference rotation speed in the determination means is set to a certain value in advance on the condition that the vehicle is in a certain driving state, such as when the throttle opening is in an idling state, Rotation speed, output shaft rotation speed of automatic transmission.

It may also be set using a data map, an arithmetic expression, etc., depending on the operating state of the vehicle, such as the engine water temperature. If a certain value is set, the controller makes a determination when the operating state of the vehicle satisfies the above-mentioned certain operating state, or sets the rotational speed of the output member detected by the rotational speed detection means to the operating state. The judgment will be made with corrections made accordingly.

Function: In such a vehicle automatic transmission, when the neutral range is selected by the selection means, in other words, when the frictional engagement device is released, the actual rotational speed of the output member of the hydrodynamic transmission device is However, it is determined whether or not the rotational speed is abnormal compared to a reference rotation speed when the frictional engagement device is normally released, thereby detecting whether or not the dragging of the frictional engagement device is abnormal. In other words, when the frictional engagement device is normally released, the rotational speed of the output member is roughly equal to the reference rotational speed depending on the load torque at that time, the torque transmission characteristics of the hydrodynamic transmission device, the driving condition of the vehicle, etc. However, if the drag of the hydrodynamic transmission device is abnormally large due to friction material peeling or oil leakage, the actual rotation speed of the output member may be lower than the reference rotation speed when the vehicle is stopped. Therefore, when coasting, it becomes too large or too small depending on the speed.

Effects of the Invention As described above, in the automatic transmission for a vehicle according to the present invention, whether or not an abnormality is caused by the dragging of the frictional engagement device is detected during normal use of the vehicle. Measures can be taken to deal with such abnormalities, such as notifying the driver, reducing engine output in the neutral range to reduce friction material wear, and even stopping the engine to prevent the abnormality from expanding in the friction engagement device. It can be done quickly.

EXAMPLE Hereinafter, an example of the present invention will be described in detail based on the drawings.

In FIG. 1, an engine 10 is controlled by an engine control computer 12, including its fuel injection valves, ignition system, and idle speed control. ! The It (ISC) valve, etc. are controlled according to the driving state of the vehicle, and the computer 12 stores the data necessary for this purpose, such as engine speed Nt, intake pipe pressure, intake air temperature, and throttle opening. Sensors 16, 18, 20, 22, 24, 26, switch 28, and automatic transmission control are used to control the automatic transmission. It is supplied from the computer 30 or the like. Further, the operation of the automatic transmission mechanism 14 is controlled by an automatic transmission control computer 30 according to the driving state of the vehicle, and the computer 30 contains data necessary for this purpose, such as throttle opening θ, vehicle speed, etc. , engine water temperature, presence or absence of brakes,
A sensor 2 detects signals indicating the shift position, selection pattern, whether overdrive is selected, etc.
2.24, 26, switch 28, sensor 36, switch 38, 40, etc. A diagnosis 42 is connected to the computer 12.30, and the abnormal area is stored based on the abnormality signal outputted from the computers 12.30. is connected and displays an error message.

The automatic transmission mechanism 14 includes, for example, a torque converter 50 and a planetary gear type transmission mechanism 52, as shown in FIG.

In the torque converter 50, the output shaft 54 of the engine 10 is connected to the pump impeller 50a, and the input shaft 56 of the transmission mechanism 52 is connected to the driven side turn impeller 50b. By being combined with the stator impeller 50c engaged via the one-way clutch, the output torque of the engine 10 converted into fluid energy is amplified and transmitted to the transmission mechanism 52. The torque converter 50 is also provided with an L/υ (lockup) clutch CL, which is engaged by a hydraulic actuator (not shown) to directly connect the input shaft 56 to the output shaft 54. In this embodiment, this torque converter 50 corresponds to a hydrodynamic transmission device.

The transmission mechanism 52 includes two single pinion type planetary gear devices 58 and 60 coaxially arranged and the input shaft 5.
6 and an output shaft 62, and the output shaft 62 is connected to the drive wheels of the vehicle via a countershaft 64, a differential gear device 66, etc.

Some of the components of the planetary gear train 58, 60 are integrally connected to each other, some are connected to the four clutches C+, C
z, C3, Cs to each other or to the input shaft 56, etc., and some of them are selectively connected to the housing 68 by two brakes B+, Bz. , some are two one-way latches F,,F.

ζ Therefore, it can be engaged with the housing 68 etc. depending on the direction of rotation.

The clutches c, ,c, ,c, ,c, ,brake B, ,
B corresponds to a frictional engagement device, such as a multi-disc clutch or a handbrake with one band or two bands in opposite directions, each actuated by a hydraulic actuator. It is now possible to The operating states of these hydraulic actuators are determined by a computer 3 by a hydraulic control circuit 70 shown in FIG.
According to the signal supplied from O, there are four forward speeds and one reverse speed with different gear ratios (rotational speed of input shaft 56/rotational speed of output shaft 62), as shown in FIG. transmission gears can be obtained. FIG. 3 shows the gears at each shift position selected by a shift lever (not shown) as a selection means, and the operating states of the clutch, brake, and one-way clutch when establishing the gears. Gear stage rlstJ.

'2nd'', r3rd'', and rO/DJ represent the forward-side first gear, second gear, third gear, and O/D (overdrive) gear, respectively.
The gear ratio becomes smaller from the first gear to the 0/D gear. "rReν" represents a reverse gear stage. Also, "○" in the column for clutches and brakes indicates the engaged state, no mark indicates the disengaged state, and "○" in the one-way clutch column indicates the engaged state when the engine is driven. . In addition, shift position "D" range, "2"
” range and “L” range are forward ranges, and “R” range is the forward range.
The range corresponds to the reverse range, and is the “N” range and the “P” range.
” range corresponds to the neutral range.

The automatic transmission control computer 30 thus controls the automatic transmission mechanism 14 based on the throttle opening θ, vehicle speed, etc.
The transmission gear ratio is changed stepwise, and at the same time, abnormalities in the frictional engagement devices, ie, clutches C, C2, C8, etc., are detected. For this purpose, the computer 30 is supplied with a signal representing the engine rotation speed N from the engine rotation speed sensor 16, in addition to the throttle opening θ, vehicle speed, etc. described above, as well as a signal representing the engine rotation speed N from the turbine rotation speed sensor 32. The output shaft rotation speed sensor 34 detects the turbine rotation speed Nt and the output shaft rotation speed N, respectively.

A signal representing this is supplied. The turbine rotation speed sensor 32 detects the rotation speed of the input shaft 56 that rotates integrally with the turbine impeller 50b, and the output shaft rotation speed sensor 34 detects the rotation speed of the output shaft 62. It consists of a well-known rotation detector such as a Cryo encoder. The turbine impeller 50b corresponds to the output member of the fluid transmission device, and the turbine rotation speed sensor 3
2 corresponds to rotation speed detection means.

Hereinafter, with reference to the flowchart of FIG. 4, the operation related to abnormality detection of the frictional engagement device will be specifically explained.

First, in step S1, a signal representing the shift position is read from the shift position sensor 36, and in step S2, the shift position is set to "N".
” It is determined whether it is in the range or not. The purpose of determining whether or not it is in the "N" range is to detect whether or not there is an abnormality, that is, excessive dragging, with all frictional engagement devices released, but in the "P" range. It is also possible to detect anomalies. In this embodiment, a selection detecting means is constituted by a portion of a series of signal processing logic by the computer 30 that executes step S2, and the shift position sensor 36.

If the judgment in step S2 is YES, that is, if the NJ range is selected, then proceed to step 33.S.
4. S5 is executed, and the throttle opening sensor 22. Engine speed sensor 16. Output shaft rotation speed sensor 34 detects throttle opening θ, engine rotation speed NE, and output shaft rotation speed N.
A signal representing 0 is read. And the next step S
6, the throttle opening θ and the engine speed N
.

, and the reference turbine rotation speed Nt+ is determined based on the output shaft rotation speed N0.

The reference turbine rotation speed N T l is the turbine rotation speed NY when the frictional engagement device is normally released.
This corresponds to the throttle opening θ.

The engine rotation speed Nt and the output shaft rotation speed N0 are determined from a predetermined data map, calculation formula, etc. based on the torque transmission characteristics of the torque converter 50 and the normal load torque when the frictional engagement device is released. However, the throttle opening θ, engine rotation speed Nt, output shaft rotation speed No., and turbine rotation speed N under various conditions. It is also possible to memorize and perform learning calculations. In addition,
The reference turbine rotation speed NTI is adjusted according to the operating condition, such as by making corrections based on the oil temperature of the hydraulic control circuit 70, engine water temperature, etc.
It is also possible to obtain even more precisely.

In the subsequent step S7, an allowable deviation ΔNi1 is calculated according to the reference turbine rotation speed NT1. This allowable deviation ΔNT+ is an allowable range in which it can be assumed that the frictional engagement device is normally released even if the reference turbine rotational speed Na and the actual turbine rotational speed Nt are different. It is determined from a predetermined data map, calculation formula, etc. according to the reference turbine rotation speed NTI, taking into account errors in the turbine rotation speed NTl, fluctuations in load torque when the frictional engagement device is released, and the like.

Thereafter, in step S8, a signal representing the actual turbine rotation speed N is read from the turbine rotation speed sensor 32, and in step S9, a signal representing the actual turbine rotation speed N is read.
It is determined whether the deviation IN air t+l between t and the reference turbine rotational speed NT1 is larger than the allowable deviation ΔNT1, in other words, whether the drag of the frictional engagement device is abnormally large.

In this embodiment, a portion of the series of signal processing logic by the computer 30 that executes step S9 above corresponds to the determining means. The reason for using the absolute value of Ny Ny+ is that when the vehicle is stopped, Nt becomes smaller than NTl due to abnormal dragging of the frictional engagement device, but when the vehicle is running (
This is because when the vehicle is coasting (coasting), Nt becomes larger or smaller than NTl depending on the speed.

If the determination in step S9 is YES, that is, if it is determined that the frictional engagement device is abnormal,
Step 310 is performed and the diagnosis 42
Then, an abnormality signal is output to the display 44, and the abnormality of the frictional engagement device is stored in the diagnosis 42, and the display 44 displays an abnormality. Abnormal indications on the display 44 include blinking or lighting of the indicator lamp,
This is done by lighting up the K monitor or displaying audio.

Further, in the next step Sll, the throttle opening degree θ is a predetermined constant value θ. or the engine speed N is a predetermined constant value N. It is determined whether the value is larger than the constant value θ. , N
E. If it is larger, the engine output is limited in step S12.

The above constant value θ. ,N. is set in advance to a value larger than the value during normal idling in order to prevent the expansion of abnormalities, such as reducing the wear of the friction material due to the dragging of the friction engagement device. Further, the engine output restriction in step S12 outputs a signal to the engine control computer 12, and, for example, restricts the amount of intake air by throttling the intake control valve, retards the ignition timing by the ignition device,
Alternatively, by limiting the amount of fuel injected by the fuel injection valve, the throttle opening θ and the engine speed N,
are all the above constant values θ. ,N. It is executed until the following occurs.

In this way, in the vehicle automatic transmission of this embodiment,
When the "N" range is selected by the shift lever and all frictional engagement devices are released, the rotation speed N of the turbine impeller 50b of the torque converter 50 is such that the frictional engagement devices are normally released. In other words, it is detected whether or not the drag of the frictional engagement device is abnormal compared to the reference turbine rotation speed NT+ in the case where the rotational speed NT+ is abnormal.

In the case of an abnormality, that fact is displayed in Diagnosis 4.
2 and displayed on the display 44,
Appropriate measures such as replacing the frictional engagement device can be quickly taken depending on the degree of abnormality. Also, in the event of an abnormality, the throttle opening θ and engine speed N. When this is high, the engine output is limited, which reduces the wear of the friction material due to dragging, and effectively prevents the abnormality from expanding.

Although one embodiment of the present invention has been described above in detail based on the drawings, the present invention can also be implemented in other embodiments.

For example, in the embodiment described above, an abnormality is determined based on whether the deviation lNtNT11 is larger than the allowable deviation ΔNtr, but the degree of abnormality is determined step by step based on the size of this deviation INair,11. Different treatments may be performed depending on the degree of abnormality.

In addition, in the above embodiment, the reference turbine rotation speed N? + is determined, but other physical quantities corresponding to the engine output, such as the intake pipe pressure or the torque of the output shaft 54, may be used instead of the throttle opening θ.

Further, in the above embodiment, abnormality detection is performed regardless of whether the vehicle is running or stopped, but abnormality detection may be performed only when the vehicle is stopped. If σ, then the deviation (Nt
+ Nt) with the allowable deviation ΔNT, and when determining the reference turbine rotation speed NA, the output shaft rotation speed N
In addition, in the above embodiment, it is necessary to detect the reference turbine rotation speed N.

Although the allowable deviation ΔNa is set with the same width above and below the standard, the upper and lower limits for determining whether or not the turbine rotational speed NT is abnormal may be set separately.

Furthermore, in the above embodiment, the selection of the "N" range is detected by the shift position sensor 36 and the execution of step S2, but the selection of the neutral range is detected by the selection means such as the shift lever. It is also possible to provide sensors for direct detection.

In addition, in the above embodiment, when an abnormality is detected, an abnormality display is displayed or the engine output is restricted, but it is also possible to stop the engine. Subsequent treatment can be determined as appropriate.

0. In addition, in the above embodiment, L/U is used as a fluid transmission device.
Although the torque converter 50 with a clutch CL is used, it is also possible to use a torque converter without an L/U clutch CL, a fluid coupling, or the like.

Furthermore, although the automatic transmission mechanism 14 of the embodiment described above includes a planetary gear type transmission mechanism 52, other types of transmission mechanisms may also be employed. The configuration of the transmission mechanism 52 and the number of gears can also be changed as appropriate.

Although other examples are not provided, the present invention can be implemented with various modifications and improvements based on the knowledge of those skilled in the art.

[Brief explanation of drawings]

FIG. 1 is a block diagram illustrating a control system of an automatic transmission for a vehicle, which is an embodiment of the present invention. FIG. 2 is a schematic diagram showing the configuration of a transmission mechanism in the automatic transmission of FIG. 1. FIG. 3 is a diagram showing the gear position of the transmission mechanism shown in FIG. 2 and the operating state of each retaining element when establishing the gear position. FIG. 4 is a flowchart illustrating the operation when detecting an abnormality in the frictional engagement device in the transmission mechanism of FIG. 2. FIG. IO: 30: 32: 50 = 0b Engine 14: Automatic transmission mechanism Automatic transmission control computer Turbine rotation speed sensor (rotation speed detection means) Torque converter (hydraulic transmission device): Turbine impeller (output member) N-th: Turbine rotation speed (rotation speed) N Month: Standard turbine rotation speed (reference rotation speed) Shift position D, 2. L: Forward range shift position R: Reverse range shift position N, P: Neutral range

Claims (1)

[Claims] Engine output is transmitted via the hydrodynamic transmission device, and the forward or reverse range is selected by the selection means, whereby the frictional engagement device is engaged to control the rotation of the engine. An automatic transmission for a vehicle that changes gears at a predetermined gear ratio and, when a neutral range is selected by the selection means, releases the frictional engagement device and cuts off the output of the engine, the automatic transmission comprising: selection detection means for detecting that the neutral range has been selected by the means; rotation speed detection means for detecting the rotation speed of the output member of the hydrodynamic transmission device; and the friction engagement device being normally released. The rotation speed of the output member of the hydrodynamic transmission device in the case is set as the reference rotation speed, and when the selection detection means detects that the neutral range is selected, the rotation speed is compared with the reference rotation speed. An automatic transmission for a vehicle, comprising: a determining means for determining whether or not the rotational speed detected by the rotational speed detection means is abnormal.