JPH0246358A - Speed change control device for automatic transmission - Google Patents

Abstract

PURPOSE:To perform a smooth speed change by setting the coupling force of a latter stage speed change means in response to the estimated torque for a fixed time until the synchronization of the input/output rotations is judged then increasing it to the preset coupling force at the time of power-on shift- down. CONSTITUTION:When power-on shift-down is detected by a kick-down detecting means (c), the preceding stage speed change means (e) of a transmission (f) is released, thus the engine rotation is quickly increased, input/output rotations of a latter stage speed change means (e) quickly approach to be synchronized. A speed change coupling force setting means (d) sets the coupling force in response to the torque from an engine which would be transmitted if the latter stage speed change means (e) has the complete coupling, estimated by a transmitted torque estimating means (b), for a fixed time until the synchronization of rotations judged by a synchronization judging means (a). Subsequently, when input/output rotating speeds are judged to be synchronized, the coupling force of the latter stage speed change means (e) is increased to the preset value. The occurrence of a speed change shock and the blow-up of the engine rotation can be suppressed.

Description

DETAILED DESCRIPTION OF THE INVENTION A1.Object of the invention (industrial application field) The present invention provides a system for automatic gear shifting by switching a power transmission path through engagement/disengagement control of a gear shifting means (hydraulic clutch, etc.). Regarding automatic transmissions.

(Prior Art) An automatic transmission is configured to automatically change gears depending on driving conditions to obtain desired driving characteristics. For this reason, it is a good practice to have a shift map in which upshift lines and downshift lines are set for each shift based on the relationship between vehicle speed and engine output, and to perform shift control by comparing the driving conditions with this shift map. It is being said. An example of such speed change control is disclosed in Japanese Patent Application Laid-open No. 189354/1983, for example.

When carrying out such speed change control, it is required to reduce shock during speed change as much as possible, and various countermeasures have been taken in the past.

For example, the shift control during power-on shift down (this refers to the state in which the accelerator pedal is depressed and the shift down is performed, and kickdown corresponds to this), when a shift command is issued, first, Disengage the front stage clutch (the clutch that was previously engaged), and then, when the input rotation and output rotation of the rear stage clutch (the clutch that is newly engaged due to gear shifting) are synchronized, the rear stage clutch Control was performed to engage the clutch. When such control is performed, there is no exchange of inertial energy between the input side and the output side when the rear-stage clutch is engaged, so there is an advantage that a smooth gear change can be performed. Note that the clutch is a speed change means, and as a speed change means of an automatic transmission, a brake in the case of a planetary speed change mechanism also corresponds to the speed change means.

However, in this control, if the synchronization point of the input and output rotations of the rear-stage clutch is detected using a timer or based on the relationship between vehicle speed and engine rotation, the influence of oil temperature and individual There is a problem in that the detection accuracy is low due to the influence of variations due to differences, the influence of slips in torque converters, fluid couplings, etc. If the detection of the synchronization point is off, for example, the engagement timing of the rear-stage clutch may become too early, causing a shift shock, or the engagement timing of the rear-stage clutch may be delayed, causing engine revving or a sense of discomfort due to a shift delay. There is a problem that

For this reason, the applicant has proposed to detect the input/output rotational speed ratio (=output rotational speed/input rotational speed) of the input side rotating member and the output side rotational member of the hydraulically operated clutch, and to detect the input/output rotational speed ratio. Synchronization of the input and output rotations is determined by detecting that the value has become approximately 1.0, and when gear changes such as power-on and downshifting are performed, the hydraulic pressure supplied to the rear clutch is We propose a control system that maintains the pressure slightly lower than the engagement start hydraulic pressure from the start of shifting until input/output rotation synchronization is determined, and then increases this hydraulic pressure to a predetermined engagement pressure after input/output rotation synchronization is determined. (Patent Application No. 63-50337).

(Problem to be Solved by the Invention) When controlling the speed change of an automatic transmission in this way, the input/output rotation speed ratio of the rear-stage clutch is directly determined by detecting the rotation of the input-side rotating member and the output-side rotating member. However, there may be a slight deviation in the detection of the synchronization point during power-on or downshifting, or the clutch for the rear stage due to this synchronization detection. If there is a slight deviation in the timing of the start of engagement, the input/output rotation speed ratio will change rapidly, so even if the deviation is small, this deviation will have a large effect, causing gear shift lock and engine revving. There is a problem in that it causes problems such as

Considering this, instead of raising the oil pressure all at once to the engagement pressure when rotation synchronization is detected, by setting this oil pressure to a value that matches the torque transmitted from the engine, the clutch oil pressure can be raised a little earlier. However, since the clutch is engaged gradually, there is less shift lag and engine revving does not occur, so it is thought that the above problems can be solved.

However, in the case of power-on downshift,
At least in the initial stage of gear shifting, the front stage clutch is disengaged, the rear stage clutch is not engaged, and the transmission capacity of the clutch is zero. For this reason, even if the engine torque is detected when the engine is running dry, it will only be a low value, and if the oil pressure is set to match this engine torque, it will be difficult to solve the above problem. There is.

Therefore, in the case of a power-on shift down, the present invention is capable of preventing gear shift lock, engine racing, etc., without being affected by errors (discrepancies) in detecting input/output rotation synchronization of the rear gear shifting means. An object of the present invention is to provide a speed change control device that can perform good speed change control.

Structure of the Invention (Means for Solving the Problems) As a means for achieving this object, the transmission control device of the present invention, as shown in the diagram corresponding to the claims in FIG. In the transmission f in which the power transmission path is selected by the disengagement control, it is detected that the relative rotational speed of the input-side rotating member and the output-side rotating member of the transmission means e has become almost zero, and the transmission When the rotational synchronization determination means a for determining input/output rotational synchronization and the rear gear transmission means e are not engaged, a problem in this transmission means e that would have occurred if the transmission means e were completely connected. The transmission torque prediction means for predicting the transmission torque includes a kickdown detection means C for detecting whether or not there is a power-on shift down. For a certain period of time until the rotation synchronization determination means a determines that the input and output rotations of the transmission means e are synchronized, the engagement force of the transmission means e is determined by the transmission torque prediction means as the engagement force corresponding to the predicted torque. Set to
After determining the synchronization, the transmission engagement force setting means d increases the engagement force to a predetermined engagement force.

Note that the rotation synchronization determining means a may determine the synchronization by detecting that the relative rotation has become approximately zero depending on whether the input/output rotation speed ratio of the transmission means e has become approximately 1.0. Furthermore, it is preferable to determine that the input and output rotations of the transmission means e are synchronized when it is detected that a state in which the relative rotation is approximately zero continues for a predetermined period of time or more.

(Function) When control is performed using the control device configured as described above, when the kickdown detection means C detects that a power-on shift down has been performed, the front speed change means (for example, a hydraulically operated clutch) is engaged. The resultant force is released and the transmission is disengaged, but at this time, since the power is on (the accelerator pedal is depressed), the engine rotation rapidly increases accordingly. The input and output rotations of the rear-stage transmission means rapidly approach synchronization. at the same time,
The transmission torque prediction means predicts the torque from the engine that would be transmitted to the rear gear transmission means if it were fully engaged at this time, and the input/output rotation speed ratio is synchronized. During a certain period of time before the transmission, the engagement force of the rear gear transmission means is set to a value necessary to generate this predicted torque. Thereafter, when the rotation synchronization determining means determines that the input/output rotational speed ratio has been synchronized (preferably, for example, it is determined that the input/output rotational speed ratio has been 1.0 for a predetermined period of time or more). 2), the engagement force of the rear gear transmission means is increased to a predetermined engagement force.

(Example) Hereinafter, specific examples will be described using the drawings.

First, the configuration of an automatic transmission having a speed change control device according to the present invention will be explained with reference to FIG. In this transmission AT, engine output transmitted from an output shaft 1 of the engine via a torque converter 2 is shifted by a transmission mechanism 10 having a gear train forming a plurality of power transmission paths. is output to. Specifically, the output of the torque converter 2 is output to an input shaft 3, and five sets of gear trains are arranged in parallel with each other between this input shaft 3 and a counter shaft 4 arranged parallel thereto. The output gear train 5 a + 5 is further arranged between the counter shaft 4 and the output shaft 6 .
It is output to the output shaft 6 via b.

The five gear trains arranged between the input shaft 3 and the counter shaft 4 are a first gear train 11a, flb, a second gear train 12a, 12b, a third gear train 13a, 13b and
4th gear train 14a, 14b and reverse gear train 15
a, 15 b, and 15 c, and each gear train has a hydraulically operated clutch 11°C+ 12C+ 13C for transmitting power through that gear train.
+ 14 C+ 15 d is provided. Note that a one-way clutch 11d is disposed in the first gear 11b. Therefore, by selectively engaging and disengaging these hydraulically operated clutches, it is possible to select power transmission by any one of the five gear trains to perform a speed change.

The operation of the five sets of hydraulically operated clutches Ilc to 15d is controlled by a hydraulic line 21 from a hydraulic control valve 2o.
This is done by hydraulic pressure supplied and discharged via a to 21e.

The hydraulic control valve 20 is operated by operating a manual valve 25 connected via a wire 45a to a shift lever 45 operated by the driver, operating two solenoid valves 22 and 23, and operating a linear solenoid valve 56. Ru.

The solenoid valves 22.23 are connected to the signal lines 31a, 3
The linear solenoid valve 58 is turned on and off by an operation signal sent from the controller 3o via the controller 1b.
is activated by a signal sent from the controller 30 via the signal line 31c. A rotation signal from a first rotation sensor 35 that detects the input rotation speed of the hydraulically operated clutch based on the rotation of the reverse gear 15c is sent to the controller 3o via a signal line 35a, and the rotation signal of the output gear 5b is sent to the controller 3o. A rotation signal from the second rotation sensor 32 that detects the output side rotation speed of the hydraulically operated clutch based on the engine throttle 41 is sent via the signal line 32a.
A throttle opening signal from a throttle opening sensor 33 that detects the opening of the throttle is sent via a signal line 33a.

Shift control in the transmission configured as described above will be explained.

The speed change control is performed according to a shift range set by the manual valve 25 in the hydraulic control valve 20 in response to the operation of the shift lever 45. These shift ranges include, for example, P, R, N, D, S, and 2 ranges, and in the P and N ranges, all hydraulically operated clutches 110 to 15d are disengaged and the transmission is in a neutral state. In the R range, the reverse hydraulically operated clutch 15d is engaged to set the reverse gear, and in the D, S, and 2 ranges, a shift is performed based on the shift map.

In this shift map, for example, the vertical axis represents the throttle opening θT.
The graph with □ and vehicle speed V on the horizontal axis has a shift-up line and a shift-down line, and the driving condition determined by the engine throttle opening (accelerator pedal depression amount) and vehicle speed is the shift-up line. When the line crosses in the up direction, an upshift is performed, and after the upshift, when the downshift line is crossed in the down direction, a downshift is performed.

Here, power-on shift down means that the accelerator pedal is depressed while driving, the throttle opening θTH suddenly increases, and the driving state crosses the downshift line from the up side area to the down side area and a downshift is performed. Tell me the case.

When the shift up line or downshift line in the shift map is crossed, the solenoid valve 22.2 is sent from the controller 30 via the signal lines 31a, 31b.
3, the hydraulic control valve 2o is operated in response to this, and each hydraulically operated clutch ll
Hydraulic pressure is supplied to and discharged from c to 15d, and upshifts or downshifts are performed.

Therefore, the controller 30 constitutes a rotational synchronization determining means, a transmission torque predicting means, and a kickdown detecting means, and the controller 30 and the hydraulic control valve 20 constitute a shift engagement force setting means.

This hydraulic control valve 20 will be explained with reference to FIG. 3.

In this control valve 20, hydraulic oil from the oil sump 7 supplied from the pump 8 is guided to the regulator valve 50 via the line 101.
0 to adjust the line pressure to a predetermined level. This line pressure is led to the manual valve 25 via the line 110, and as the manual valve 25 operates and the various valves in the control valve 20 operate, the line pressure is applied to the hydraulically operated clutches 11c+ 12c, 13G for each speed stage.
+ 14 CI 15 d is selectively supplied according to driving conditions, and the operation of each clutch is controlled.

Here, first, various valves within the control valve 20 will be explained. The check valve 52 is disposed downstream of the regulator valve 50 and prevents the oil pressure of the lubricating oil sent to the lubrication section of the transmission through the line 102 from exceeding a predetermined pressure. The modulator valve 54 reduces the line pressure sent through the line 103 to create a predetermined nomosulator pressure, and supplies hydraulic fluid at this modulator pressure to the torque converter 2 through the line 104.
The line 1 is supplied to a lock-up clutch control circuit (not shown) for lock-up clutch control.
05 through the first and second solenoid valves 22.2
3 for shift valve operation control.

The manual valve 25 is operated in conjunction with a shift lever 45 operated by the driver.p.

Position ff in any of the 6 positions: R, N, D, S, 2
Then, the line pressure from the line 11o is selectively supplied to the lines 25a to 25g according to each position.

1-2 shift valve 80.2-3 shift pulp 82.3
-4 shift valve 64 is similar to manual valve 25,
When in either position S or 2, the operation is controlled by the action of the modulated pressure supplied via the lines 106a to 106f in response to the ON@OFF operation of the first and second solenoid valves 22.23. , clutches 11c+ 12c+ 13c for 1st to 4th speed
, 14c is a valve that controls supply and discharge of line pressure to and from the line pressure.

Lines 106a and 106b are the first solenoid valve 22
and the line 10 through the orifice 22a.
Therefore, when the first solenoid valve 22 is de-energized, the boat to the drain side is closed and the line 105 is connected to the lines 10Ela and 10E3b.
Hydraulic oil with a modulated pressure is supplied from the pump, and when the electricity is turned on, the boat to the drain side is opened and the pressure in the lines 108a and 106b becomes almost zero. Further, the lines 108c to 106r are connected to the second solenoid valve 23 and also to the line 105 via the orifice 23a, and when the second solenoid valve 23 is de-energized, the port to the drain side is closed. Hydraulic oil with modulated pressure is supplied from line 105 to lines 106c to 106f, and when the above-mentioned energization is on, the port to the drain side is opened and line 1
The pressure from 08c to 106f becomes almost zero.

Here, the line 106a is connected to the right end of the 1-2 shift valve 60, and the line 106b is connected to the 2-3 shift valve 62.
The line 106c is connected to the left end of the 1-2 shift valve 60, the line 106e is connected to the right end of the 3-4 shift valve 64, and the line 106f is connected to the left end of the 2-3 shift valve 62. Note that the line 106e,
1013f is manual valve 25 and line 106
It is connected to the second solenoid valve 23 via d. Therefore, if the supply and discharge of the modulated pressure from the line 105 to each line 106a to 108f is controlled by controlling the energization on/off of the first and second solenoid valves 22 and 23, 1-2.2 -3°3-4 shift pulp 60,62.
64, thereby controlling the line pressure supplied from the line 110 via the manual valve 25 to each hydraulically operated clutch 11c+ 12c+
13c+14c can be selectively supplied to perform a desired speed change.

This control valve 20 has first to fourth orifice control pulps 70, 72, 74, 76, and these orifice control valves allow the release of the hydraulic pressure in the hydraulic chamber of the front clutch during gear shifting to the hydraulic pressure of the rear clutch. This is done at the same time as the oil pressure in the room increases. The first orifice control valve 70 controls the hydraulic release timing of the third gear clutch when shifting from third gear to second gear, and the second orifice control valve 72 controls the timing of hydraulic release of the third gear clutch when shifting from second gear to third gear or from second gear to fourth gear. The hydraulic release timing of the 2nd speed clutch is controlled,
The third orifice control valve 74 controls the hydraulic release timing of the 4th gear clutch when shifting from 4th gear to 3rd gear or from 4th gear to 2nd gear, and the fourth orifice control valve 76 controls the timing for shifting from 3rd gear to 4th gear. Time 3
The hydraulic release timing of the speed clutch is controlled.

Furthermore, each hydraulically operated clutch 11 C+ 12 C+
Accumulators 81, 82, 83, 84 having pressure receiving chambers communicating with the hydraulic chambers 13c+14c are provided, and the pressure receiving chambers of these accumulators and the piston member 8
Lines 121, 122, 123, 124 are connected to the opposing back pressure chambers via 1a, 82a + 83a, 84a, and these lines 121, 122, 123.1
24 is connected to linear solenoid valve 56 via lines 120a, 120b and 120.

The linear solenoid valve 56 is a linear solenoid 68
By controlling the current flowing to the linear solenoid 56a, its operating force is controlled, and the magnitude of the hydraulic pressure supplied to the line 120 (this is referred to as control hydraulic pressure P?H) is controlled. be able to. For this reason,
By controlling the current supplied to the linear solenoid 56a, it is possible to control the oil pressure in the back pressure chamber of each of the accumulators 81 to 84, thereby controlling the oil pressure in the oil pressure chamber of the engagement clutch (second stage clutch) during gear shifting. The engaging force of this clutch (transmission means) can be controlled freely.

The clutch pressure control valve 78 is disposed on the line from the manual valve 25 to the 1-2 shift valve 60, and is a valve that operates in response to the control pressure PTH regulated by the linear solenoid valve 56. .

Therefore, the line pressure (referred to as clutch pressure P.L) supplied to each hydraulically operated clutch 11C, 12C113C+14c via each shift valve 60, 62, 84 is adjusted to the control pressure by the clutch pressure control valve 78. Controlled according to P7□. In addition, the control pressure PTH is controlled to be a pressure corresponding to the accelerator pedal opening, that is, the engine output, except when changing gears. Therefore, the pressure PTH for each clutch operation depends on the engine output. The pressure can be as low as possible to obtain the corresponding required torque capacity.

In the control valve 20 configured as described above, the manual valve 2 can be operated by operating the shift lever 45.
Operation of 5 and ON/O of solenoid valves 22 and 23
Each of the above valves is operated by the FF operation, and line pressure is selectively supplied to each clutch tic~15d,
Automatic gear shifting is performed, and since its operation is conventionally known, a description thereof will be omitted.

In the transmission configured as described above, shift control when power-on downshift is performed will be explained using the flowchart of FIG. 4 and the graph of FIG. 5.

In this control, first, in step S2, the current speed S is determined from the shift map. Search the target speed stage S1 for
In step S4, it is determined whether the two are equal.

s, = So is the case where the shift command is not output, and in this case, the process proceeds to steps 88 to S10,
Restart the shift judgment timer T, and increase the clutch pressure P.

Set L to the maximum pressure and perform the current quick installation S. be maintained as is.

This state is shown in the portion up to time 1+ in FIG. 5, where the shift command from the controller 30 and the output of the shift solenoids 22 and 23 are at the current speed S. is set. Therefore, the current speed stage S. and the target speed S, are the same, and the input/output rotation speed ratio e CLO (= e (!La)) of the clutch for this speed is 1.0. Also, the control pressure PTH is controlled by the linear solenoid valve 56. Hydraulically operated clutch (transmission means) that is set to maximum and sets the current speed accordingly
Clutch pressure PcL is also maximum.

In this state, when the accelerator pedal is depressed at time t, the throttle opening θa suddenly increases, and a shift command for downshifting is output in response to this, the target speed S is changed to a new one. Therefore, Sa≠So
Then, the process proceeds to step S12 and determines whether S is <So or not.
That is, it is determined whether or not the shift is down. In the case of upshifting, the process advances to step 814, where gear change processing for this purpose is performed. In the case of downshifting, the process proceeds to step 5IEi, where it is determined whether or not the power is on. If the power is not on, the process proceeds to step S14, where a corresponding speed change process is performed. Note that since the present invention deals with power-on and downshifting, a description of other shift control, that is, the control at step SL4, will be omitted. Note that this is the current speed stage S when a gear change command is output and a gear change is performed. is the front stage, and the target speed stage S is the rear stage.

If it is a power-on downshift, step 8
Proceed to 1B, and from the output of this speed change command, the speed change judgment timer T
The process waits for the set time I to elapse, and then proceeds to step S20. This shift judgment timer T+ is used to prevent the shift busy feeling caused by shifting according to the shift command when the shift command is changed within a short period of time. After the shift command to 3rd gear is output, if a shift command from 3rd gear to 2nd gear is further output before the shift judgment timer T1 elapses, when the shift judgment timer T elapses. Then, a shift from 4th gear to 2nd gear is performed.

Therefore, as shown in FIG. 5, at time t, the current speed gear S. When a shift command from to target speed S1 is output, the shift solenoid output is S at time t2 after the shift determination timer T1 has elapsed. is changed from SL to SL. However, at the time when the shift command is output at time t1, the target speed gear S1 is changed to one corresponding to this day order, and therefore, as shown in FIG. 5, the target speed gear (later gear) clutch input/output Rotation speed ratio e. L is changed to the value e1 at the clutch of this target speed stage at time tl.

At time t2, when the shift solenoid output is changed to S, the current speed stage S. The clutch pressure P CLO of the hydraulically operated clutch (for the front stage) is released to the drain side and rapidly decreases. At the same time, the working oil pressure of the clutch for the target speed So (later stage) is set, and at this time, the input/output rotation speed e of the clutch for the target speed So is set. L, is detected and this is the predetermined value e. It is determined whether e C is greater than spo (step 520);
La > e. In the case of spo, that is, the input/output rotation speed ratio e of the target speed stage. L, is the predetermined value e. If the SPD has not yet been reached, the clutch pressure P is increased in step S22. , is set to the minimum value.

This setting is performed by minimizing the control pressure PTH by the linear solenoid valve 56, and when the clutch pressure PcL is the minimum, the target speed clutch is in a disengaged state. At this time, the accelerator pedal is depressed and the throttle opening θ7H is in an open state (power-on state), so the engine rotation rapidly increases, and the input side rotation speed of the target speed clutch also rapidly increases accordingly. The input/output rotation speed ratio e of this clutch increases. L rapidly decreases toward 1.0.

Then, e CLa≦e cspo (time ta)
Then, the process advances to step S24, and this rotational speed ratio e is determined. L.

is 1.0+α (however, α is an extremely small value), that is, it is determined whether the target speed clutch is fully engaged (step 524) o ecta
> (1,0+α), that is, if the target speed clutch is still in the half-engaged state, step 8
The process proceeds to steps 26 to 830, restarts the engagement judgment timer Tpc, calculates the predicted transmission torque ETQ, and calculates the predicted transmission torque ETQ.
The latch pressure P required to generate TQ. L(ETQ)
Set.

This predicted transmission torque ETQ refers to the torque from the engine that is transmitted through the clutch for the target speed when the clutch is engaged, and as shown in FIG. This torque ETQ is obtained by reading from a graph set based on the relationship with the engine speed Ne. Note that this torque ETQ is generally proportional to the throttle opening 0H, so the throttle opening θT
A simple method may be used in which the torque ETQ is calculated by multiplying H by a predetermined coefficient k. Furthermore, as shown in Figure 7,
Corresponding to this torque ETQ, a latch pressure PcL required to obtain this torque ETQ is calculated and set, and from this graph, the latch pressure PCL (ETQ) required to generate the torque ETQ is read. Note that this clutch pressure P. L (ETQ) is linear solenoid valve 56
Hunt roll pressure P? H to a predetermined value PTH(ETQ
).

Therefore, at time t3, the control pressure P■ is PT
N (ETQ), and the clutch pressure P correspondingly increases. L is a hydraulic pressure P that generates the same torque as the predicted transmission torque ETQ. It becomes L(ETQ). In the target speed clutch, the input/output side members gradually start to engage, and the clutch is engaged without causing a shift shock or an increase in engine speed.

Accordingly, the input/output rotation speed e of the clutch for the target speed stage is
If CLa becomes smaller than (1,0+α) and it is determined that this clutch is almost engaged, step 332
After waiting for the engagement judgment timer T'pc to elapse (from time t4 to t5), the target speed S1 is changed to the current speed S. The settings are closed (step 534). Therefore, in the next flow, s,=
S, the process proceeds to step S8, and the clutch pressure P
. , is increased to the maximum pressure (predetermined engagement pressure).

Note that the time point when the target gear clutch is engaged (time t4
), the clutch pressure P. It is possible to raise L to the maximum, but - There is often some clutch slippage at time t4, and if the clutch pressure is increased to the maximum, this slight slippage will be suddenly absorbed. Shift stains may occur. In particular, as shown in Figure 8, the friction coefficient of the clutch friction member often has a characteristic that it increases rapidly near the relative rotation of zero, and the torque immediately before the clutch engages. Since the fluctuations (increases) are large, even if a slight amount of slippage is absorbed, the accompanying torque fluctuations will become large and there is a high possibility that the shift shock will become large.

For this reason, as described above, in this control, an engagement judgment timer Tpc is provided, and when eOLa≦(1°0+α) (the target speed clutch is engaged!), this timer TFC is set. If the clutch pressure PcL continues for more than a certain period of time, the clutch pressure P.L is increased to the maximum pressure.By doing this, when the clutch pressure PcL is increased to the maximum pressure, slippage in this clutch is completely eliminated. This eliminates the occurrence of shift shock as described above.

By performing the above control, a power-on downshift with less shift shock is realized, and as shown in the graph at the bottom of FIG. 5, changes in the acceleration (deceleration) speed G acting on the vehicle also become smooth.

In addition, in this example, the input/output rotation speed ratio of the clutch is approximately 1.0.
The synchronization of rotations that allow people to turn is determined by determining whether or not the number of rotations that can be attended by people is determined. It's okay.

Furthermore, in this example, the clutch pressure P. Although an example has been shown in which L is controlled using the control pressure PTH that acts as back pressure of the accumulator, the present invention is not limited to this, and for example, the clutch pressure may be directly controlled by a linear solenoid valve or the like. You can also
The load roll pressure Pt□ of this example may be created by a solenoid valve whose hydraulic pressure is duty-controlled.

C1 As described in detail of the invention, according to the present invention, when a shift-on shift is performed, the hydraulic pressure of the transmission means for the previous gear is released, and the engagement of this transmission means is released. When the power is on, the engine speed increases accordingly, and the input and output rotations of the rear gear transmission rapidly approach synchronization, but it takes a long time until the input and output rotations become synchronized. During a certain period of time, the engagement force of the rear gear shifting means is
The transmission torque is set to a value necessary to generate the predicted transmission torque that would have been generated if the transmission means were engaged, and then
When it is determined that synchronization has been achieved, such as when the input/output rotation speed becomes 1.0 (preferably, when it is determined that the state where the input/output rotation speed ratio is 1.0 continues for a predetermined period of time or more) Since the engagement force is increased to a predetermined value at the time of /f queen downshift, the rear gear shifting means is engaged early based on the predicted transmission torque, and the synchronization point is detected. It is possible to smoothly maintain the shifting means regardless of the error in the speed change, and to suppress occurrence of shift lock and engine rotational speed.

[Brief explanation of the drawing]

Fig. 1 is a claim correspondence diagram showing the configuration of the present invention, Fig. 2 is a schematic diagram showing an automatic transmission equipped with a control device according to the present invention, and Fig. 3 shows a hydraulic control valve constituting the above control device. Hydraulic circuit diagram, Figures 4 and 5 are flowcharts and graphs showing control details by the above control device, Figure 6 is an explanatory diagram for calculating predicted transmission torque, and Figure 7 is a diagram showing the relationship between the predicted transmission torque and clutch pressure. Graph showing the relationship FIG. 8 is a graph showing the relationship between the clutch relative rotational speed and the friction coefficient of the friction member. 2...Torque converter 10...Transmission mechanism 20.
... Hydraulic control valve 22.23 ... Shift solenoid valve 25 ... Manual valve 32.35 ... Rotation sensor 56 ... Linear solenoid valve Fig. 1

Claims (1)

[Scope of Claims] 1) A power transmission means that constitutes a plurality of power transmission paths, and a plurality of speed change means that are controlled to engage and disengage in order to select the power transmission path by this power transmission means. In the automatic transmission, rotational synchronization determining means detects that the relative rotation between the input-side rotational member and the output-side rotational member of the transmission means becomes substantially zero, and determines input/output rotational synchronization of the transmission means; A transmission torque prediction means for predicting the transmission torque that would be generated in the transmission means if the transmission means for the rear gear is fully engaged when the transmission means for the rear gear is not engaged; a kickdown detection means for detecting whether the power-on shift is detected by the kickdown detection means;
A certain period of time until the rotational synchronization determining means determines that the input and output rotations of the rear gear transmission are synchronized is set to an engagement force corresponding to the torque predicted by the transmission torque predicting means, and 1. A shift control device for an automatic transmission, comprising: a shift engagement force setting means for increasing the engagement force to a predetermined engagement force. 2) detecting that the rotation speed ratio of the input-side rotating member and the output-side rotating member of the speed change means has become approximately 1.0, and detecting that the relative rotation has become approximately zero; A speed change control device for an automatic transmission according to claim 1. 3) When the rotational synchronization determining means detects that a state in which the relative rotation between the input-side rotating member and the output-side rotating member of the transmission means has been approximately zero has continued for a predetermined time or more,
3. The speed change control device for an automatic transmission according to claim 1, further comprising means for determining that input and output rotations of the speed change means are synchronized.