JP2864402B2 - Shift control method for automatic transmission for vehicle - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial applications]

The present invention relates to a shift control method for an automatic transmission that issues a shift command when a predetermined timer has elapsed after a shift determination.

[Prior art]

In general, an automatic transmission so that issues a shift command after shift determination is the timer T ₁ of the for wait before issuing a shift command is provided from a lapse of the timer T ₁ of the for this waiting. The standby timer T ₁ is one that is provided to issue a shift command based on when the plurality of shift determination is made in a very short time, the most recently made the shift determination, any normal automatic It is also provided on the transmission. By the way, in order to reduce a shift shock, an automatic transmission is often configured to achieve a shift by locking a one-way clutch instead of engaging a friction engagement device. In this case, during a coast in which the driving direction is reversed, the one-way clutch idles, and a power phenomenon from the wheel side is not transmitted to the engine side (a phenomenon in which engine braking is not effective) occurs. For this reason, in general, in an automatic transmission, a shift range in which an engine brake is effective, such as an L range or two ranges, is separately provided in addition to the drive range. When the driver selects this engine brake range, the shift range is provided in parallel with the one-way clutch. In this case, the coasting friction engagement device is separately engaged to apply the engine brake (even if a slight shift shock occurs). (Idling stage). On the other hand, in an automatic transmission, a shift (upshift) is often performed as the power generation unit (engine) changes from driving to driven. Conventionally, when an upshift is performed in accordance with the change from the driving to the driven, the upshift is performed from the idle speed (in the drive range) as described above to the speed to a higher speed side. In the case of a shift, an automatic transmission configured to execute a shift according to a special control logic such as postponing a point at which the shift is commanded earlier to maintain good shift characteristics is known. (For example, JP-A-1-247854). To explain with reference to FIG. 7 of the above techniques, when the second speed stage was idling stage now driven at time S ₁ → change in the driven occurs, the second speed in association with this change If shift determination from the stage to the third speed stage occurs when thus if on the basis of the shift determination issues a shift command at time S ₂ which is waiting timer T ₁ described above has elapsed after the time lag Tt the shift is started at the time S _3. However, at the time of the time S _3, since the input shaft rotation speed of the automatic transmission is not synchronized yet with the output shaft rotational speed to force the synchronous rotational speed input shaft rotation speed of the automatic transmission by the shift command Therefore, the inertia of the input system including the engine generates a positive torque as indicated by the arrow, which appears as a shift shock (solid line in FIG. 7). Therefore, if such a shift determination is made, a shift instruction is not issued immediately based on the shift determination, but the shift instruction is extended for a while. (Even if the output shaft (vehicle speed) of the automatic transmission is reduced). The rotation of the input shaft of the automatic transmission naturally drops due to the friction of the engine due to the idling speed (even if the rotation does not decrease), and eventually falls to the rotation speed after the gear ratio is switched (synchronous rotation speed). Come. Therefore, by waiting for the rotation speed to drop to this synchronous speed and issuing a shift command at time S ₄ (actually slightly before this because of the time lag), the occurrence of inertia torque can be prevented and almost no shift shock occurs The shift can be achieved without performing the operation (see the broken line in FIG. 7).

[Problems to be solved by the invention]

However, in detecting that the rotation speed of the input shaft of the automatic transmission has decreased to the synchronous rotation speed, if this is detected by a timer, differences and variations in various running conditions, for example, idle up However, there is a problem that it is not always possible to accurately detect the time when the input shaft rotation speed has reached the synchronous rotation speed due to variations in the throttle damper and the like. At this point, the method of actually detecting the rotational speed of the rotating member and monitoring that the rotational speed of the input shaft has reached the synchronous rotational speed is based on the fact that the synchronous rotational speed is reached regardless of various running conditions. It is excellent in that it can detect accurately. However, for example, when the vehicle speed is low and the engine speed drop to the synchronous speed is small, or when the air conditioner is in use, for example, when the engine speed is high and the engine speed is high, the engine speed is low. rotational speed of the input shaft of the automatic transmission is reduced to a synchronous rotational speed very quickly, if the elapsed before the shift command condition of the standby timer T ₁ of the order corresponding to the multiple shift has become established It is possible. However, the standby timer T ₁ is originally, which is provided in order to give shift command based on the final shift determination when there is a plurality of shift determination during the timer T ₁ only power-off upshift of the shift judgment speak one made during the standby timer T ₁ shift determination from idling stage. Therefore, even if the condition for shifting can perform a fully small shift shock and thus out previously shift command of the standby timer T _1, another shift decision is made immediately, for example, the accelerator is depressed is in the Even if it does, it will not be possible to respond promptly to this new shift decision. As a result, there is a problem that the power-off upshift cannot smoothly cope with the multiple shifts that can be normally performed. The present invention has been made in view of such a conventional problem, and enables a power-off upshift from an idling speed to be always realized with a small shift shock, and also satisfactorily supports multiple shifts. It is an object of the present invention to provide a shift control method for an automatic transmission for a vehicle that can perform the shift control.

[Means for Solving the Problems]

The present invention relates to a shift control method for an automatic transmission in which a shift command is issued when a predetermined timer has elapsed after a shift is determined, as shown in FIG. A procedure for detecting whether or not the vehicle is in the gear position, and before the predetermined timer elapses after the shift determination,
In the procedure for detecting whether or not the power generation unit has changed from driving to driven, and in the shift speed in which the power generation unit is idle in the driven state,
When it is detected that the power generation unit has changed from driving to driven before the predetermined timer elapses from the shift determination,
A procedure for switching the timing of issuing the shift command from a point in time when the predetermined timer has elapsed to a point in time determined by monitoring the rotation speed of the rotating member; and a step in which the shift command time is determined by monitoring the rotation speed of the rotating member. A step of checking whether or not the predetermined timer has elapsed, and a step of issuing a shift command after the predetermined timer has elapsed, if the predetermined timer has not yet elapsed. The above object has been achieved by including the above.

[Action]

According to the present invention, in the shift speed in which the idle state occurs in the driven state, the power generation unit switches from driving to driven within a “predetermined time” (before a predetermined timer elapses) to cope with multiple shifts from the shift determination. When the change is detected, the timing for issuing the shift command at that stage is switched from the determination based on the elapse of the predetermined timer to the determination by monitoring the rotational speed of the rotating member. As a result, a shift command can always be issued when the input shaft rotational speed of the automatic transmission reaches the synchronous rotational speed regardless of the difference in the running conditions and various variations, and the power-of-upshift from the idling speed can be performed. Shift shock can be reliably suppressed. Then, in the present invention, when the shift command timing is determined by monitoring the rotational speed of the rotating member, it is once again confirmed whether or not the "predetermined time" has elapsed, and the "predetermined time" When the predetermined time has not yet elapsed, the gear change command is issued after the elapse of the "predetermined time", that is, after the elapse of a predetermined timer. As a result, it is possible to secure a standby for a "predetermined time" with respect to the multiple shifts as before, and it is possible to promptly respond to a plurality of shift determinations during the "predetermined time". (See FIGS. 6A to 6C).

【Example】

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 2 is a skeleton diagram showing an embodiment of the vehicular automatic transmission according to the present invention. In the figure, a block 1 is an engine, which drives a pump impeller 4 serving as an input rotating member of a fluid torque converter 3 via a crankshaft 2. The hydraulic converter 3 is of a type known per se, and includes a pump impeller 4 driven by the engine 1 via the crankshaft 2, a stator 7 supported on a housing 6 via a one-way clutch 5, and a turbine 8 including. This turbine 8 is supported by a rotating shaft 14. The rotating shaft 14 is a fluid torque converter 3
At the same time as the output shaft of the first gear transmission mechanism
It also functions as 12 input shafts. A lock-up clutch 10 selectively connects the crankshaft 2 directly to the rotating shaft 14. The first gear transmission mechanism 12 is an underdrive mechanism that selectively achieves a plurality of shift speeds with a reduction ratio of 1 or more. This gear transmission mechanism 12 includes a first planetary gear mechanism 15 and a second planetary gear mechanism 16. The first planetary gear mechanism 15 includes a sun gear 17, a planetary pinion 18, a ring gear 19, and a carrier that rotatably supports the planetary pinion 18.
Contains 20. Clutch C ₁ is incorporated between the input shaft 14 and the ring gear 19. Also, the clutch C ₂ is incorporated between the input shaft 14 and the sun gear 17 or the shaft 27 connected with the sun gear 17. Further, the sun gear 17 or the shaft 27
Brake B ₁ is disposed between the housing 26 and. The second planetary gear mechanism 16 includes a sun gear 30, a planetary pinion 31, a ring gear 32, and the planetary pinion 31.
And a carrier 33 rotatably supporting the carrier. The sun gear 30 is connected to the shaft 27. Between the shaft 27 and the housing 26, the one-way clutch F ₁ and the brake B ₂ is incorporated in series. Further, the one-way clutch F ₂ and the brake B ₁ is incorporated in parallel between the carrier 33 and the housing 26. The carrier 20 of the first planetary gear mechanism 15 and the ring gear 32 of the second planetary gear mechanism 16 are supported by the input shaft 14 and connected to the shaft 40. Axis 40 is the first
Also functions as an output shaft of the planetary gear mechanism 12. A counter drive gear 53 is mounted on the shaft 40. The second gear transmission 13 configured as an underdrive mechanism has a planetary gear mechanism 41. The planetary gear mechanism
41 is sun gear 42, planetary pinion 43, ring gear 44
And a carrier 45 for rotatably supporting the planetary pinion 43. Between the sun gear shaft 47 and the carrier 45 supporting a sun gear 42 or which is adapted to have been built-in clutch C _3, selectively connecting the two rotary elements to each other. Brake B ₄ is incorporated between the sun gear shaft 47 and the housing 26 the sun gear 42 or that this support is adapted to selectively braking rotation of the sun gear 42. Further is the one-way clutch F ₃ incorporated between the sun gear shaft 47 and the housing 26 for supporting the sun gear 42 or it, the sun gear 42 by the operating state of the engine, even when the brake B ₄ is not engaged
It is designed to brake the rotation of. The sun gear shaft 47 is formed as a hollow shaft, and a counter shaft 55 is provided through the hollow portion concentrically. A counter drive gear 53 and a counter driven gear 54 are meshed with one end of the counter shaft 55 by a spline 56 so that torque can be transmitted. The ring gear 44 is connected to the counter shaft 55 by a spline 57 so as to be able to transmit torque. The carrier 45 is connected to a part thereof with a torque transmission member 58 extending in the axial direction on the outer periphery of the ring gear 44. Via the torque transmitting member 58, the carrier 45 is connected in a torque transmitting relationship to a differential drive gear 60 rotatably mounted on the counter shaft 55 by a radial thrust bearing 59. The counter shaft 55 is disposed parallel to a central axis common to the torque converter 3 and the first gear transmission mechanism 12. The counter driven gear 54, the second gear transmission mechanism 13, and the differential drive gear 60, which are arranged concentrically on the counter shaft 55, also have a central axis common to the torque converter 3 and the first gear transmission mechanism 12. They are arranged along a central axis arranged in parallel to the other. The differential drive gear 60 meshes with a differential driven gear 62 of a differential gear mechanism 61. The differential gear mechanism 61 is of a type known per se, and includes two pairs of bevel gears 63, 64, 65, 66.
Is included. Of these, one pair of bevel gears 65 and 66 are connected to the differential driven gear 62, and the other pair of bevel gears
63 and 64 are connected to a pair of front axles 67 and 68, respectively. The counter shaft 55 is supported at one end by a ball bearing 70 via a boss 69 of the counter driven gear 54, and at the other end by a roller bearing 71. In the drawing, reference numeral 80 denotes an output shaft speed sensor (vehicle speed sensor), and 82 denotes an engine speed sensor. The automatic transmission includes the gear train as described above, and shifts are performed by selectively engaging or disengaging each friction engagement device as shown in FIG. In FIG. 3, E is a corresponding clutch,
Alternatively, it indicates that the brake is engaged.
(E) indicates that the corresponding one-way clutch is engaged only in the engine drive state (drive state) and is not engaged in the engine brake state (driven state). Further, e indicates that the corresponding one-way clutch is engaged in the engine drive state, but the engagement is not necessarily required because the transmission of power is guaranteed by the clutch or brake incorporated in parallel with this. Is shown. In this automatic transmission, the first speed and the second speed in the live range are idle. The hardware configuration of the gear train is not particularly different from the conventional one. FIG. 4 shows a control flow executed in the automatic transmission. This control flow is started when a specific shift determination is made. First, in step 200, it is determined whether or not the current gear position of the automatic transmission is the idle speed, that is, the first speed or the second speed. If it is not the idle speed, that is, if it is the third speed or the fourth speed, all the following steps are bypassed and this flow is exited. In step 202, it is determined whether the vehicle is in the power-on state (driving state). If it is determined that the camera is in the power-off state (driven state), the process proceeds to step 204, where it is determined whether the power has been turned off for the first time.
The first time is determined and switched from the OFF state to the power-on time, the process proceeds to step 206, the timer T ₁ of the for standby to cope with multiple shift whether it is in operation is determined.
When the timer T ₁ is is determined to be in operation, whether a downshift is determined proceeds to step 208, when was downshifting output immediately downshift at step 210 is performed, the power-off downshift Exit from this flowchart to execute the control for On the other hand, not a downshift at step 208, that is, when it is determined that the upshift is a driving → driven during operation of the timer T ₁ is detected, in order to achieve a power-off upshift from idle stage proceeds to step 212 to set the N ₃ flag. The N ₃ flag rather than the timer T ₁ hitting to the timing decision to issue a shift command, a flag indicating that it should perform the rotation speed of the monitoring of the rotary member. This together with the N ₃ flag is set, N ₃ map selected at step 214 is performed. This N ₃ is calculated in step 216
Are constants used in the conditional expression to be determined in step (1), and are mapped according to the type of shift and the vehicle speed, for example, as shown in FIG. The is N ₃ according to the type of transmission has been changed, the time lag until the actual gear shift is started after the shift command is issued by the friction engagement devices involved are different.
Also, depending on the vehicle speed, the N ₃ is changed, as when the vehicle speed is higher at the same time lag is due to the large rotation speed decreases therebetween. Incidentally, to select a map of N ₃ in this position is to select the map in accordance with most of the new shift determination in based transmission type and vehicle speed information of the shift determination to be updated in real time. In step _{216 Ne <N 0 × ih +} N 3 The condition determining timing of shift command based on the expression is performed. Here, Ne is the smooth rotation speed of the engine (rotation speed corrected for the influence of pulsation), N ₀ is the output shaft rotation speed of the automatic transmission, and ih is the gear ratio of the automatic transmission after shifting. Unless this condition is satisfied, the process returns as it is, and the determination in step 216 is repeated through steps 202, 204, 230, and 214. Eventually, the conditional expression in step 216 is satisfied, the flow N ₃ flag is canceled timer T ₁ again proceeds to step 220 whether it is in operation is determined. This is because even if the conditional expression in step 216 is satisfied, the standby timer for coping with multiple shifts is still
When T ₁ is was in operation, the up timer T ₁ is passed is waiting for the speed change output. When the timer T ₁ is detected as being inoperative, the shift output is issued proceeds to step 222. When it is determined in step 202 that the power is on, the process proceeds to step 224 to determine whether or not the power was on last time in order to know whether or not the power is on for the first time. Only 1 when the power-on time, the process proceeds to step 226, where the cancellation of N ₃ flag is performed. This is because when again as a power-on while waiting for the condition is satisfied in step 216 does not pass through the step 218, N ₃ at step 226
This is for canceling. Further, when the determination of N ₀ is made in step 204, that is, when it is determined that the power-off state is also last time, the process proceeds to step 230, where it is determined whether the N ₃ flag is operating, and the operation is performed. When it is in the middle, the process proceeds to step 214, and when it is not in operation, the process proceeds to step 220. The root of this step 204,230,220, the timer T ₁ is determined to be still in operation when it reaches the step 220 via step 216 and 218, will follow when it is returned. In this case the shift output is issued after waiting for the timer T _1. Summarizing the above control flow, there is a change from the power-on during operation of the standby timer T ₁ of the order corresponding to the multiple shift to the power-off, and if there upshift, determining the timing for issuing a shift command Before starting, timer
Is switched from the method according to T ₁ in a method for monitoring the rotational speed of the rotary member, so that the shift command waiting condition is satisfied in expression in step 216 is issued. However, even if this condition is satisfied, the shift output is issued after waiting for the timer T ₁ when the waiting timer T ₁ itself was still in operation. Thus, a power-off upshift from a so-called idling speed can always be realized with a small shift shock irrespective of various running conditions and the like, and it is possible to appropriately cope with various types of shifts. become. The configuration and has the value of N ₃ used in the conditional expression according to the rotational speed of the monitoring of the rotation member is mapped, depending on the type and speed of the transmission, moreover the selection of this map value is updated in real time since the turned, since the "synchronous timing" is detected in accordance with the optimum N ₃ value according to the type of the transmission, always be able to issue a shift command at the optimum time.

【The invention's effect】

As described above, according to the present invention, the power-off upshift from the idle speed can always be realized with a small shift shock regardless of various running conditions, and
An excellent effect of being able to cope with multiple shifts without any trouble is obtained.

[Brief description of the drawings]

FIG. 1 is a flowchart showing the gist of the present invention, FIG. 2 is an overall skeleton diagram of an automatic transmission for a vehicle to which an embodiment of the present invention is applied, and FIG. 3 is friction engagement of the automatic transmission. diagram showing the engagement state of the apparatus, FIG. 4 is a flow diagram showing a control flow executed by the automatic transmission, Fig. 5, graph showing an example of a map of N _3, FIG. 6 (a FIGS. 7A to 7C are diagrams showing the relationship between the standby timer T ₁ for explaining the operation of the present invention, the synchronization detection time point and the shift command, and FIG. 7 is a diagram explaining the underlying technology of the present invention. FIG. 5 is a shift transient characteristic diagram for performing a shift. C ₁ -C ₃ ... clutch, B ₁ .about.B ₄ ... brake, F ₁ to F ₃ ... one-way clutch, 1 ... engine, 10 ... torque converter,
12: first gear transmission, 13: second gear transmission, 80: output shaft speed sensor, 82: engine speed sensor, T ₁ : standby timer, Ne: engine speed, N ₀ : output shaft speed speed,
ih: gear ratio after shifting, N ₃ : constant.

Claims (1)

(57) [Claims] 1. A shift control method for an automatic transmission, which issues a shift command when a predetermined timer has elapsed after a shift determination has been made. And a step of detecting whether or not the power generation unit has changed from driving to driven before the predetermined timer elapses after the shift is determined; and If it is detected that the power generation unit has changed from driving to driven before the predetermined timer elapses from the shift determination, the timing at which the shift command is issued is changed from the time when the predetermined timer elapses to the time when the rotation member is rotated. Switching the time to the time determined by the rotation speed monitor, and determining whether or not the predetermined timer has elapsed when the shift command time is determined by the rotation speed monitor of the rotating member. A step of confirming, and, if the predetermined timer has not yet elapsed, a step of issuing a shift command after the predetermined timer has elapsed, and a shift control method for an automatic transmission.