JPH0492153A - Speed change control of automatic transmission - Google Patents

Abstract

PURPOSE:To miniaturize a whole automatic transmission and to improve fuel consumption by combining engagement and release of a frictional engagement means to set specific speed change steps and selecting a combination to enlarge a moment of inertia of a gear train. CONSTITUTION:Speed change control objective of an automatic speed changer A is carrier out by judging speed change steps to set in accordance with traveling condition of a car speed V, throttle start theta and others and by outputting a speed change command signal from an electronic control unit 11 to a hydraulic control device C. In this case, as regards a speed change step with a plural kinds of engagement and release patterns, the engagement and release patterns are selected in consideration of the situation that the number of frictional engagement means to actuate to change over at the time of speed changing is comparatively small and that the variable number of rotation of a rotary member is small and others. Additionally, in the case when a moment of inertia as a whole of a gear train in accordance with the release pattern, the engagement and release patterns where the amount of inertia grow large are selected when or after the release pattern changes or has changed in speed.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention This invention relates to a method of controlling gear changes in an automatic transmission.

2. Description of the Related Art It is well known that an automatic transmission, which automatically changes gears based on driving conditions, is connected to an engine via a fluid coupling (specifically, a torque converter). The fluid coupling provides a flow of fluid such as oil generated by the pump impeller to the turbine launch to drive the turbine launch, so it itself has a buffering effect and blocks the transmission of vibrations from the engine. fulfill a function.

On the other hand, since the fluid coupling does not directly connect the pump impeller on the driving side and the turbine runner on the driven side, the torque transmission efficiency will not be 100%. Therefore, conventionally, a lock-up clutch has been provided to mechanically connect a driving side member and a driven side member for the purpose of improving the fuel efficiency of a vehicle.

However, since a lock-up clutch directly mechanically connects the driving side member and the driven side member,
Engine vibrations are also transmitted, resulting in poor ride comfort and increased muffled noise. Therefore, conventionally, the speed range in which the lock-up clutch is engaged is set on the high-speed side, and the lock-up clutch is released in the low-speed range where engine torque fluctuations are relatively large.
We are trying to take advantage of the buffering effect of the fluid coupling.

Further, Japanese Patent Application Laid-Open No. 63-251661 describes a torque converter in which an annular weight is attached to a turbine launch via a centrifugal clutch.

This is to prevent vibration by increasing the moment of inertia of the turbine launch in the high speed range where the lock-up clutch is engaged.

Problems to be Solved by the Invention According to the configuration described in the above-mentioned publication, the allocation effect is increased by adding an annular weight, but it is difficult to add a new weight to a torque converter whose primary function is torque transmission. Therefore, it is necessary to secure a space for this purpose, which causes disadvantages such as an increase in the size of the torque converter, which in turn increases the size of the automatic transmission, and increases weight and cost.

This invention was made against the background of the above-mentioned circumstances, and it is an object of the present invention to provide a control method for an automatic transmission that can obtain an excellent vibration damping effect without adding a new mass body. .

Means for Solving the Problems In order to achieve the above object, the method of the present invention includes a gear train having a plurality of combinations of engagement and disengagement of frictional engagement means for setting a predetermined gear stage. In the automatic transmission, the method is characterized in that the combination of engagement and disengagement of the frictional engagement means for setting the predetermined gear stage is selected as a combination that increases the moment of inertia in the gear train.

Operation The automatic transmission to which the present invention is directed includes a gear train that has a plurality of combinations of engagement and disengagement of frictional engagement means for setting a predetermined gear stage. When setting to that gear, avoid so-called simultaneous gear shifting where the fluctuating rotational speed of the rotating member decreases for each combination, or where the number of frictional engagement means that must be switched between engaged and disengaged states is three or more. However, in the method of the present invention, when setting the predetermined gear, the gear shift command signal causes the gear to be set using a combination that increases the moment of inertia in the gear train. Set. Here, the moment of inertia is determined by the mass and the radius from the center of rotation, so if at least one of them is large, the combination will be selected such that the moment of inertia is large.As a result, the vibration damping effect of the gear train will be large. Become.

Example Next, the present invention will be explained based on examples.

The basic configuration of an apparatus capable of implementing the method of the present invention is shown in the block diagram of FIG. The automatic transmission A, which is connected to the engine E via a joint T that can be directly connected mechanically, has multiple types of engagement/disengagement combinations of frictional engagement means to set a predetermined gear stage. It is configured.

These gears are set based on predetermined driving conditions such as vehicle speed V and throttle opening θ (valves of the hydraulic control device C are switched by a command signal from the gear setting means 10, thereby causing frictional engagement. The gear setting means 10 is engaged or released as appropriate and set.The gear setting means 10 outputs to the hydraulic control device C a combination that increases the moment of inertia of the gear train when setting the predetermined gear. It looks like this.

An example of the automatic transmission described above is schematically shown in a skeleton diagram in FIG. 2, and the gear train shown here is mainly composed of three sets of single pinion type planetary gear mechanisms 1.23. That is, the carrier IC of the first planetary gear mechanism 1, the ring gear 2R of the second planetary gear mechanism 2, and the ring gear 3R of the third planetary gear mechanism 3 are connected so as to rotate as a unit. The sun gear IS of the planetary gear mechanism 1 is connected to the carrier 2C of the second planetary gear mechanism 2 via the second clutch means 2, while the sun gear IS of the second planetary gear mechanism 2 is connected to the fourth clutch means via 4. is connected to. Further, the carrier 2c of the second planetary gear mechanism 2 is connected to the sun gear 3S of the third planetary gear mechanism 3 via a fifth clutch means 5.

Note that as a connection structure for each of the above-mentioned elements, a connection structure used in general automatic transmissions such as a hollow shaft, a solid shaft, or an appropriate connecting drum can be used.

The input shaft 4 is connected to an engine (not shown) via a power transmission means such as a torque converter or a fluid coupling that includes a mechanism capable of mechanical direct connection such as a lock-up clutch. A first clutch means 1 is provided between the input shaft 4 and the ring gear IR of the first planetary gear mechanism 1, and a first clutch means 1 is provided between the input shaft 4 and the ring gear IS of the first planetary gear mechanism 1. A third clutch means 3 is provided between the two for selectively connecting the two.

In addition, in practical use, since there are restrictions on the arrangement of each component, each clutch means Kl, 2 and 3. 4. to 5
Of course, a suitable intermediate member such as a connecting drum may be interposed as a connecting member for the connecting member.

Further, as a brake means for preventing the rotation of the rotating members in the above-mentioned planetary gear mechanism 1, 2.3, a first brake means Bl for selectively preventing rotation of the sun gear 3S of the third planetary gear mechanism 3, and a second A second brake means B2 that selectively blocks the rotation of the carrier 2C of the gear mechanism 2, a third brake means B3 that selectively blocks the rotation of the sun gear 2S of the second planetary gear mechanism 2, and a first planetary gear mechanism. 4th brake means B4 for selectively blocking rotation of sun gear IS 1;
and is provided.

In addition, in practical use, these brake means Bl,
B2. B3. B4 and these brake means Bl, B2.
B3. Of course, an appropriate connecting member can be interposed between each element to be fixed by B4 or between the case 6 and the case 6.

An output shaft 5 that transmits rotation to a propeller shaft and a counter gear (not shown) is connected to the carrier 3C of the third planetary gear mechanism 3.

The automatic transmission with the configuration shown in FIG. 1 has five forward speeds and one reverse speed as the main gears, and between the second forward speed and the third forward speed there are so-called 22nd speed and 2.5th speed. With the addition of a gear stage,
And so-called 32nd speed and 35th speed are located between the 3rd forward speed and the 4th speed.
and 4.5 speed between 4th and 5th speeds.
In principle, it is possible to set 10 forward speeds and 1 reverse speed with additional speeds, and it is also possible to set 2nd, 2nd, 3rd and 3rd speeds.
For gears other than 2nd gear, 35th gear, 45th gear, and 5th gear, a combination of engagement and release of the clutch means and brake means (so-called engagement and release pattern) is used to set the gear position. ), and these are shown in Table 1 as an operation table. In Table 1, the ○ mark indicates engagement, the blank indicates disengagement, and the asterisk (*) indicates that it may be engaged. Items that do not cause changes in ratio or rotation status,
This includes cases in which the gear ratio does not change when released but the rotational state changes, and cases in which the gear ratio and rotational state do not change even if the gear ratio is released as long as other means marked with an asterisk (*) are engaged. In addition, in Table 1, the columns marked with a, b, c, etc. for 2nd, 3rd, 4th, 5th, and reverse gears indicate the settings for setting the gears. Among the engagement/disengagement patterns, the rotational speeds of the rotating elements of the planetary gear mechanism are different, but these are engagement/release patterns, and the symbols ■, ■, ■, etc. indicate the rotational speeds of the rotating elements of the planetary gear mechanism. represents the type of engagement/release patterns even though they do not differ. Further, Table 2 shows an example of the rotation speed of each rotating member in the gear train as a ratio when the input shaft rotation speed is "1".

(This page, blank space below) Table 1 Table 1 shows the gears that can be set in principle.
In practical use, the gear that is superior in terms of power performance, acceleration, etc. is selected and set from among these gears.

The clutch means and the brake means are used as a control device for performing speed change control for setting any of the gears shown in Table 1 and for determining engagement/disengagement patterns for setting the gears. A hydraulic control device C supplies and discharges hydraulic pressure to engage and release these, and an electronic control unit (ECU) outputs electrical instruction signals to the hydraulic control device C based on various input data.
) 11 are provided. The hydraulic control device C is equipped with a pressure regulating valve, a speed change control valve, a solenoid valve for operating the speed change control valve, etc., and can adopt a conventionally known device. The object directly controlled by this is, for example, a solenoid valve in the hydraulic control device C.

In the control of the shift according to the method of the present invention for the above-mentioned automatic transmission, the gear stage is determined to be set based on driving conditions such as the vehicle speed V and the throttle opening θ. This is done by outputting a speed change command signal to the control device C. In that case, if the gear has multiple types of engagement/disengagement patterns,
The engagement/disengagement pattern is selected in consideration of the fact that the number of frictional engagement means to be switched during gear shifting is as small as possible, and that the fluctuating rotational speed of the rotating member is small. Furthermore, if the moment of inertia of the gear train as a whole differs depending on the engagement/disengagement pattern, the engagement/disengagement pattern that increases the moment of inertia is selected at the time of shifting or after the completion of shifting.

An example thereof will be explained according to the flowchart of FIG.

In the automatic transmission equipped with the gear train shown in Fig. 2, the pattern shown in column a (3-a pattern) is one in which the rotational speed of the rotating member differs among the engagement/release patterns for setting the third speed. ), the pattern shown in column b (referred to as 3-b pattern), and the pattern shown in column C (referred to as 3-C pattern) (see Tables 1 and 2). These engagement/disengagement patterns are selected according to the engagement/disengagement pattern of the gear immediately before shifting to the third gear.

In addition, in the third speed, the rotation speed of the input shaft 4 is substantially reduced by the third planetary gear mechanism 3 and transmitted to the output shaft 5,
Therefore, the first planetary gear mechanism 1 rotates as a whole, and the second planetary gear mechanism 2 does not participate in torque transmission, so its sun gear 2S or carrier 2C can be fixed.

Therefore, as shown in the flowchart of FIG. 3, first in step 1 it is determined whether to shift to the third speed, and then in the following step 2 it is determined whether the 3-C pattern is selected. When the 3C pattern is selected, the first clutch means Kl of the 3-C pattern,
The third speed is set by selecting the pattern (3) in which the third clutch means 3 and the first brake means B1 are engaged (step 3). Counter T started at the same time
When the value of I exceeds a predetermined reference value α and the judgment result in step 4 becomes "yes", the second clutch means 2 or the fourth clutch means 4 is engaged. As a result, as is known from Table 2, the entire second planetary gear mechanism 2 rotates as a unit, so that the moment of inertia of the gear train as a whole increases.

On the other hand, when setting the third speed, if the 3-C pattern is not selected, that is, if the judgment result in step 2 is "no", proceed to step 6 and select the 3-a pattern or 3-b pattern. Select and set 3rd speed. When the value of counter T2, which was started at the same time, exceeds a predetermined reference value β and the judgment result in step 7 becomes "yes", the process proceeds to step 3, and the subsequent steps 4 and 5 are controlled. . As a result, the entire second planetary gear mechanism 2 eventually rotates as a unit, and the moment of inertia of the gear train as a whole increases.

Note that as an engagement/release pattern for setting 3rd gear, for example, if it is a downshift from 4th gear, 3-
If the pattern in the column ■ or ■ is selected among the C patterns, the second clutch means 2 or the fourth clutch means 4 has already been engaged during gear shifting, so the flowchart in FIG. 3 is applied. Of these, control in steps 4 and 5 will not be performed.

Therefore, according to the above-mentioned device, even if a mechanically directly connected mechanism such as a lock-up clutch in the fluid coupling between the gear train and the engine is engaged in the third gear, the output shaft side Since the moment of inertia of the engine is increased and the damping effect is excellent, it is possible to suppress vibrations transmitted from the engine and reduce muffled noise.

In the above example, the second clutch means 2 or the fourth clutch means 4 is always engaged in the third speed, but these clutch means 2. 4 is engaged in order to enhance the vibration damping effect, for example, the fourth
As shown in the figure, when it is predicted or detected that the engine vibration is large (step 10), at least one of the clutch means 2. 4 (step 11), or when it is predicted or detected that the muffled noise is loud as shown in FIG. 5 (step 2G), at least one of the clutch means 2. 4 may be engaged (step 21).

In addition, as a method of increasing the moment of inertia, in addition to rotating the entire planetary gear mechanism that is not involved in torque transmission, there is also a pattern in which the rotation speed of one of the rotating members is increased,
Alternatively, a method may be adopted in which a pattern for rotating a rotating member having a large diameter is selected. Therefore, it is also possible to perform control to increase the moment of inertia at gears other than the third speed shown in the above embodiment.

Furthermore, this invention is applicable to the automatic transmission having the structure shown in FIG.
No. 1, Japanese Patent Application No. 1-185152, Japanese Patent Application No. 1-1869
No. 91, Japanese Patent Application No. 1-186992, Japanese Patent Application No. 1-205
478, Japanese Patent Application No. 1-280957, etc., and the various configurations described in the drawings.

As described in detail, according to the control method of the present invention, the moment of inertia on the output shaft side is greater than the joint mechanism that connects the automatic transmission to the engine, and this is achieved only by the gear train. Therefore, it is possible to obtain an excellent vibration damping effect without using any special additional members. Accordingly, according to the present invention, the entire automatic transmission can be downsized, and lock-up at low speeds can be improved. It becomes possible to use a clutch and improve fuel efficiency.

[Brief explanation of drawings]

FIG. 1 is a block diagram for explaining the basic configuration of an apparatus for carrying out the present invention, FIG. 2 is a skeleton diagram showing the automatic transmission, FIG. 3 is a flowchart showing a control routine in an embodiment, and FIG. Each of FIG. 5 and FIG. 5 is a flowchart for explaining another subroutine for controlling the second clutch means or the fourth clutch means. 1.2.3... Planetary gear mechanism, 4... Input shaft, 5...
- Output shaft, 10... Gear stage setting means, 11-1° electronic control unit, A... Automatic transmission, C
...Hydraulic control device. Applicant Toyota Motor Corporation Representative Patent Attorney Takeshi Watanabe Mistake 1 Figure 3 Figure 2-34, 7-

Claims (1)

[Scope of Claims] An automatic transmission equipped with a gear train having a plurality of combinations of engagement and disengagement of frictional engagement means for setting a predetermined gear, comprising: A speed change control method for an automatic transmission, comprising selecting a combination of engagement and disengagement of frictional engagement means that increases the moment of inertia in a gear train.