JPH0320167A - Shift controller for automatic transmission - Google Patents

Abstract

PURPOSE:To abate the occurrence of a shift shock by releasing an engine brake friction element temporarily over a range from before to after completion of an up-shift at a time when this up-shift takes place in a clamped state of the engine brake friction element. CONSTITUTION:An automatic transmission selects gear ratio of a gear train with selective clamp/release motion of plural numbers of friction elements, and transmits turning effort of an engine (c) to the driving wheel side via one- way clutch (d). If engine brake operation is required hereat, an engine brake control means (f) clamps an engine brake friction element (e), transmitting the turning effort out of the driving wheel side to the side of the engine (c). Accordingly, when an up-shift is carried out in a clamped state of the engine brake friction element (e), this element (e) is temporarily released over a range from before to after completion of this up-shift, and engine speed is lowered in the wake of a drop in throttle opening. Thus a shift shock at time of the up-shift is abatable in this way.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a shift control device for an automatic transmission mounted on a vehicle.

2. Description of the Related Art Conventional automatic transmissions for vehicles include, for example, Japanese Patent Application Laid-Open No. 1983-
As disclosed in Japanese Patent No. 62047, a plurality of frictional elements such as clutches and brakes are incorporated into a gear train equipped with two sets of iIl star gear sets, and by appropriately engaging or disengaging these plurality of frictional elements, The combination of the components of the planetary gear set is changed to provide a plurality of gears.

In addition to the above-mentioned friction elements, the gear train of such an automatic transmission incorporates a one-way clutch (forward one-way clutch) that is locked when outputting engine rotation to the drive wheels, and the action of the one-way clutch ensures smooth transmission. This allows for easy gear changes.

By the way, such a one-way clutch... If such a clutch is provided, when rotational force is applied manually from the drive wheel side, the one-way clutch becomes free and rotates freely, making it impossible to apply engine braking.

For this reason, an engine brake friction element (overrun clutch) is provided in parallel with the one-way clutch, and when the engine brake is activated, the engine brake friction element is engaged, thereby disabling the function of the one-way clutch. It is configured so that it can operate.

Problems to be Solved by the Invention However, in such conventional automatic transmissions, when upshifting from a low gear to a high gear while the engine brake is activated, for example, when the foot is released in manual I range, Assuming that an upshift is performed from 1st gear to 2nd gear, the rotation of the driving wheels is input to the engine with a large gear ratio in 1st gear, so the engine rotational speed becomes significantly high. In the second gear, the gear ratio becomes smaller, so the rotational speed input to the engine from the driving wheel side is reduced.

However, since the speed of the vehicle during a gear change that is processed within a short time is approximately constant, the rotational speed of the drive wheels is approximately the same in 1st gear and 2nd gear, and therefore, when shifting to 2nd gear, the speed of the vehicle is approximately constant. When the gear shift is completed, the engine, which had previously been running at a relatively high RPM in 1st gear, is suddenly forced to run at a relatively low RPM in 2nd gear, causing a huge shock. There was a problem in that the problem occurred.

SUMMARY OF THE INVENTION In view of these conventional problems, an object of the present invention is to provide a shift control device for an automatic transmission that can smoothly shift gears even during an upshift while engine braking is continued. shall be.

Means for Solving the Problems In order to achieve the above object, the present invention, as shown in FIG. , engine C in the power transmission path of gear train b.
a one-way clutch d that is locked when the rotational force is transmitted to the driving wheels; and a one-way clutch d that is arranged in parallel with the one-way clutch d and is engaged when the engine brake is activated to transmit the rotational force from the driving wheels to the engine. In an automatic transmission equipped with an engine brake friction element e, when an upshift is performed from a low gear to a high gear with the engine brake friction element e engaged, the upshift is completed before the upshift is completed. engine brake control means f for temporarily releasing the engine friction element e afterward;
It is configured by providing

In the shift control device for an automatic transmission according to the above-described structure, during an upshift while engine braking is continued, the entraining friction element e is temporarily released, so that the one-way clutch d is activated. Gear train B becomes free and idles, and at this time the rotational force input to engine C from the drive wheel side is cut off, so the engine speed decreases in accordance with the decrease in throttle opening. .

Therefore, by the time the engine brake friction element e is re-engaged after the gear shift is completed to the high gear side, the engine speed has already been reduced, so the rotation of the drive wheel side is affected by the gear ratio at the high gear. When power is input to the engine, the rotational difference between the engine rotational speed and the rotational speed manually applied from the drive wheel side is significantly reduced.

Example Hereinafter, embodiments of the present invention will be described in detail based on the drawings.

That is, FIG. 2 shows an embodiment of the shift control device for an automatic transmission according to the present invention. , and an auxiliary transmission 14 that performs constant speed two-speed switching are arranged in series.

The gear trains of the main transmission 12 and the sub-transmission 14 are constructed as shown in FIG. 3, and the main transmission l2 is connected to the first planetary gear set PC. and the second planetary gear set PC. and? The sub-transmission 14 is equipped with a third planetary gear set PC. It is equipped with

The first, second and third planetary gear set PG. ,PC■PGS
are configured as simple planetary gears, and the first, second,
3rd Sangiya S. , S,, S3, the first, second, and third pinion gears P,, P■ P, and the first. 2nd and 3rd ring gear R. R■ R, and the first, second, and third pinion carriers PC. , PC■PC. It is composed of

Further, in the main transmission 12, the first and second planetary gear sets PG
r. As shown in the figure, the gear train composed of PGm includes a ripper clutch R/C that connects the input shaft 16 and the first sun gear S, and a high clutch H/C that connects the input shaft 16 and the first pinion carrier PC+. C, first pinion carrier PC. forward clutch F/C that connects and second ring gear R; band brake B/B that fixes the first sun gear S to the casing K side; Reverse brake L&R/
A friction element such as B is provided.

Furthermore, the gear train includes the forward clutch F.
A forward one-way clutch P/O-C is provided between the /C and the second ring gear R, which is locked when the rotational force of the engine E is transmitted to the driving wheels, and is released when the rotation is reversed. and the first pinion carrier PC. An overrun clutch 0-R/C as an engine brake friction element is arranged in parallel with the forward one-way clutch F/O-C between the forward one-way clutch F/O-C and the second engine gear R.

Note that a row one-way clutch L/O-C is provided between the first pinion carrier PC and the casing K.

In addition, in the sub-transmission 14, the gear train composed of the 311th star gear set PGs includes a third pinion carrier PC. A direct clutch D/C that connects the third sun gear S and the third sun gear S, and a duct brake R-D/B that fixes the third sun gear Ss to the casing K are provided.

Further, a reduction gear f R-D/O-C is disposed between the third sun gear S3 and the casing K.

The second pinion carrier PC, which serves as an output member of the main transmission 12, and the third ring gear R, which serves as an input member of the auxiliary transmission Jall4, are connected via an intermediate shaft 18.

In addition, the input shaft 16 in FIG.
The rotational force of the engine E is manually applied via the torque converter T/C.

By the way, in the main transmission [112], each friction element (R/C, H/C, F/C, B
/B, L&R/B) are engaged and released by the shift hydraulic pressure supplied from the control valve 2o shown in FIG. 1, so that various shift stages can be obtained.

(Left space below) Table 1 In the same table, the O mark indicates a fastened state, and the blank mark indicates a released state.

Further, the forward one-way clutch F/O・C is free when the second ring gear R is rotated in the forward rotation direction with respect to the first pinion carrier Pct, and is locked when it is rotated in the reverse direction. L/
OC is the first pinion carrier pc. Free when rotating in the forward direction, locked when rotating in the reverse direction.

By the way, the above-mentioned overrun clutch O-R/C is
Although not shown in the table, the forward one-way clutch F/C is engaged when engine braking is required, and the overrun clutch 0/R/C is engaged.
The first pinion carrier PC. and the second ring gear R, and the rotational force from the drive wheel side can be transmitted to the engine E side, so that the engine brake is operated.

On the other hand, in the sub-transmission 14, the direct clutch D/
When C is engaged, manual rotation is outputted at a constant speed, and when the direct clutch D/C is released, a deceleration effect is performed.

In addition, the above reduction one-way clutch R-D/O
-C becomes free when the third sun gear S3 rotates in the normal direction, and is locked when the third sun gear S3 rotates in the reverse direction.

Therefore, in the automatic transmission 10, the main transmission l2
By the combination of the gear change and the two-gear change by the auxiliary transmission 14, six forward gears are set so that a total of five gears are shifted, as shown in Table 2 below.

Table 2 The above control valve 20 includes a first shift solenoid 22 and a second shift solenoid 24 for switching the main transmission ml2, and a third shift solenoid 2 for switching the auxiliary transmission l4.
6 are provided, and these first, second, and third shift solenoids 22, 24, and 26 are connected to an A/T control unit 28.
The above-mentioned friction elements are engaged by being driven ON and OFF by control signals output from the . The release is switched so that each gear stage is obtained as shown in Table 3 below.

(Margin below) Table 3 By the way, from the A/T control unit 28 to the first, second, and third shift solenoids 22, 24, 26
The ON and OFF signals output to the throttle sensor 3
Throttle opening signal and vehicle speed sensor 3 detected at 0
The vehicle speed signals detected at step 2 are inputted, and a shift determination is made based on a preset shift schedule based on these signals.

By the way, since the automatic transmission 10 of this embodiment has five forward gears, the ranges selected by the select lever (not shown) are P, R, N, D, III, ■,
Equipped with I range positions, P range is in full gear state, R range is in reverse state, N range is in neutral state, D range is in forward gear automatic gear shift state, ■ range is in 3rd gear engine braking state, ■ range In range 2, the 2nd speed engine brake state is obtained, and in range 1, the 1st speed engine brake state is obtained.

In addition, the above select lever has an O-drive (O-drive).
D) A prohibition switch is provided, and the prohibition and execution of the fifth speed are selected by the drive prohibition switch.

By the way, the engine brake is controlled by engaging the overrun clutch O-R/C when the accelerator opening is 1/16 or less on the low gear side below 4th gear in the D range. is engaged and the engine brake is operated, but in addition to this, for example, in the 2nd and 3rd speeds of the ■range and the 1st and 2nd speeds of the ■range, etc. The overrun clutch 0.R/C is engaged in the entire accelerator opening range.

The engagement and disengagement of the overrun clutches 0 and R/C is controlled by the engine brake control means 40 built in the A/T control unit 28, which turns on and off the overrun clutch solenoid 42 provided in the control valve 20. This is done by outputting an OFF signal.

That is, as shown in FIG. 4, the overrun clutch solenoid 42, the overrun clutch control valve 46, and the overrun clutch reducing valve 48 are provided in the control valve 20, and the overrun clutch solenoid 42 is turned ON. When this occurs, the pilot oil pressure A is supplied to the overrun clutch control valve 46 as a switching pressure.

Then, the overrun clutch solenoid 42 is turned ON.
By supplying the pilot oil pressure A to the overrun clutch control valve 46, the Subur 46a is set to the upper position in the figure, and when the pilot oil pressure A is drained by turning off the overrun clutch solenoid 42, Subur 46a is set at the lower position in the figure.

The overrun clutch control valve 46 cuts off the supplied line pressure when the subur 46a is in the upper position in the drawing, and overruns the supplied line pressure when the subur 46a is in the lower position in the drawing. It is supplied to the overrun clutch 0-R/C via the run clutch reducing valve 48 and engaged.

In addition, the above-mentioned overrun clutch reducing valve 4
8 reduces the supplied line pressure to an appropriate pressure and supplies it to the overrun clutch O-R/C.

In this embodiment, the engine brake control means 40 incorporates a program in accordance with the flowchart of FIG. 5, which will be described later, so that the overrun clutch 0-R
Control is performed to release /C positionally and temporally.

That is, the flowchart shown in FIG. 5 shows an example of the processing of the program executed by the engine brake control means 40. First, when the l speed state is read in step 100, the throttle opening degree and vehicle speed are read in step 101. Based on the throttle opening degree and vehicle speed, it is determined in step 102 whether or not to upshift to second gear based on the shift schedule.

If rNOJ is determined in step 102, it is determined that the 1st gear state will continue, and step 1 is determined as follows.
On the other hand, if it is determined to be YESJ, the process proceeds to step 103, where it is determined whether the upshift is being performed in the ■ range, and if rNOJ, the process proceeds to step 104, where the third As shown in the table, an OFF signal is output to the first shift solenoid 22 to upshift to the second speed with the overrun clutch 0.R/C engaged.

On the other hand, if rYEsJ is determined in step 103, the process proceeds to step 105, where the overrun clutch solenoid 42 is switched ON and the overrun clutch 0 is turned on.
・Release R/C.

Then, the process proceeds from step 105 to step 106 and step 107, and in step 106, after an ON signal is output to the overrun clutch solenoid 42, the L
, seconds have elapsed, the first shift solenoid 22 is turned off.
Switch to F and upshift to 2nd gear.

Next, in step 107, an OFF signal is output to the overrun clutch solenoid 42 at a time point t seconds after the ON signal is output to the overrun clutch solenoid 42 in step 105, and an OFF signal is output to the overrun clutch solenoid 42. - Re-conclude R/C.

Note that the time t for executing step 106 is set shorter than the time t for executing step 107.

With the above configuration, in the automatic transmission shift control device of this embodiment, when the select lever is set to the H range and the engine brake is activated and the foot is released from the accelerator pedal, the throttle opening will change. It may be upshifted as it decreases, and at this upshift, the 6th
As shown in the figure, before the first shift solenoid 22 is turned off, the overrun clutch solenoid 42 is turned on, and the overrun clutch O-R/C is released.

When the overrun clutch O-R/C is released in this way, the forward one-way clutch P/0・C shown in FIG. The train is idled.

Then, since the accelerator pedal has been released, the rotational speed of the engine E is reduced, and then the first shift solenoid 22 is turned off and the gear is upshifted to the second speed.
After the shift to the second speed is completed, the overrun clutch solenoid 42 is turned off, and the overrun clutch O-R/C is engaged again.

By the way, when the engine brake is operated in the first gear with a large gear ratio, the rotation of the driving wheels is greatly increased and input to the engine E, but in the first gear with a smaller gear ratio than the first gear. In the second speed state, the number of rotations input to the engine E decreases by the decrease in the gear ratio.

Therefore, in this embodiment, as described above, the engine speed is lowered before upshifting to second gear and engaging the overrun clutch 0-R/C. When C is engaged and the rotation of the driving wheels is input to the engine E via the gear train in the second gear state, there is a difference between the rotation speed of the engine E and the rotation speed input from the drive wheels. It is possible to significantly reduce the rotational difference between the two, and due to this reduction in rotational difference, the shift shock during upshifting is significantly reduced.

In this embodiment, the explanation was given using an example of upshifting from 1st speed to 2nd speed in the ■ range, but the example is not limited to this, and for example, upshifting from 2nd speed to 3rd speed in the ■ range. The present invention can be applied to upshifts, etc., but in particular,
By applying the present invention at the time of upshifting from the first gear to the second gear as described in this embodiment, it is possible to obtain a remarkable effect of reducing shift shock.

In addition, in the above embodiment, in the first and second speeds of the ■ range, the overrun clutch is 0-R/C in the entire accelerator opening range.
Although the explanation has been made assuming that the overrun clutch O-R/C is in the engaged state, the present invention is not limited to this, and for example, the overrun clutch O-R/C may be engaged only when the accelerator opening is 1/16 or less. A similar effect can be obtained by keeping the overrun clutch O-R/C in the released state from before to after the shift is completed.

Furthermore, in the above embodiment, the main transmission l2 and the auxiliary transmission l
Although the present invention is applied to an automatic transmission 10 that is equipped with 4 and 4 and can provide five forward speeds, the present invention is not limited thereto, and may be applied to other automatic transmissions, such as conventional examples. It goes without saying that the present invention can be applied to an automatic transmission having four forward speeds as shown in FIG.

Effects of the Invention As explained above, in the automatic transmission shift control device of the present invention, the engine brake friction element incorporated in the power transmission path of the gear train has the following effects when engine braking is continued. When upshifting from a low gear to a high gear, it is temporarily released, so when upshifting while engine braking is continued, the gear train is released at the stage when the engine brake friction element is released. The engine enters an idling state, and the engine speed is reduced in accordance with the reduction in throttle opening that induces an upshift.

Therefore, by the time the engine friction element is re-engaged after the gear shift has been completed to the high gear side, the engine engine rotational speed has been reduced, so it is possible to significantly reduce the shift shock during upshifts. This has the excellent effect of significantly improving vehicle ride comfort.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram showing the concept of the present invention, FIG. 2 is a schematic diagram showing an embodiment of the present invention, and FIG. 3 is a schematic diagram showing a gear train of an automatic transmission to which the present invention is applied. FIG. 4 is a schematic configuration diagram showing the main parts of the hydraulic pressure control circuit applied to the present invention, FIG. 5 is a flowchart showing an example of processing of a program executed by the present invention, and FIG. 6 is a flowchart showing a processing example of a program executed by the present invention. 5 is a time chart showing the relationship between engine brake control timing and shift timing. lO...Automatic transmission, 12...Main transmission, 14...
・Sub-transmission, 20...Control valve, 22,2
4.26...Shift solenoid, 28...A/T control unit, 40...Engine brake control means, 42...Overrun rough solenoid, 0
・R/C...Overrun clutch (friction element for engine), F/O-C...Forward one-way clutch (one-way clutch), R/C...Reverse clutch, H/C...High clutch , F/C...Forward clutch, B/B...Band brake, L&
R/B...low and reverse brake, D/C...
・Direct clutch, R-D/B...Reduction brake, PG+...1st planetary gear set, PG1...2nd iI! Star gear set, PGs'...Third planetary gear set. Figure 2 E Figure 4 Figure 5 Figure 6 2nd shift solenoid ON 3rd shift solenoid ON

Claims (1)

[Claims] (1) When equipped with a gear train in which the gear ratio is switched by a combination of engagement and disengagement of a plurality of friction elements, and the rotational force of the engine is transmitted to the driving wheels during the power transmission path of the gear train. In an automatic transmission equipped with a one-way clutch that is locked to the engine, and an engine brake friction element that is arranged in parallel with the one-way clutch and is engaged when the engine brake is activated to transmit rotational force from the driving wheels to the engine. , Engine brake control that temporarily releases the engine brake friction element from before the upshift is completed to after the upshift is completed when upshifting from a low gear to a high gear with the engine brake friction element being engaged. 1. A speed change control device for an automatic transmission, characterized in that a means is provided.