JP2845401B2 - Control device for automatic transmission for vehicles - Google Patents

Description

Description: FIELD OF THE INVENTION The present invention relates to a control device for an automatic transmission for a vehicle,
The present invention relates to a control device for promoting the rise of engine rotation during a downshift due to depression.

2. Description of the Related Art A conventional automatic transmission for a vehicle is disclosed in, for example,
A plurality of friction elements such as clutches and brakes are arranged in a power train in which two sets (front side and rear side) of a planetary gear set are incorporated. Is appropriately engaged and released, the combination of the components (sun gear, planet carrier, and internal gear) of the planetary gear device is changed, so that a plurality of shift speeds can be obtained.

The friction element is provided with a forward clutch which is set to be always engaged in the forward gear, and a forward one-way clutch is arranged in series with the forward clutch.

The forward one-way clutch is locked when the number of revolutions on the input side is greater than the number of revolutions on the output side, that is, in a state where the engine rotation is transmitted to the drive wheels.

Therefore, when the number of revolutions on the drive wheel side increases on a downhill or the like, the forward one-way clutch becomes free.

For this reason, in the vehicle automatic transmission, an overrun clutch is provided in parallel with the forward one-way clutch, and when engine braking is required, the overrun clutch can be engaged to directly connect the drive wheel side to the engine. ing.

Problems to be Solved by the Invention By the way, in such a conventional automatic transmission for a vehicle, when the accelerator pedal is depressed to accelerate from a constant running state, the throttle opening is reduced as shown in the shift schedule of FIG. Is shifted down with the increase of.

The shift down is performed by releasing the friction element that determines the high gear and engaging the friction element on the low gear, but in the upshift state and the downshift state, due to the difference in gear ratio, the rotation on the drive wheel side is performed. The number of revolutions of the engine corresponding to the number is increased, and when the friction element for determining the downshift is engaged, rotation is input from the driving wheel side, so that the forward one-way clutch is in a free state.

As a result, the vehicle does not accelerate until the forward one-way clutch is locked, so that the driver takes a long time from when the accelerator pedal is depressed until the driver actually feels acceleration, and the acceleration feeling and response are deteriorated. There was a problem of doing it.

In view of the above-mentioned conventional problems, the present invention aims at improving acceleration feeling and response at the time of a step-down downshift by engaging a friction element arranged in parallel with the one-way clutch at the time of a step-down shift. It is an object of the present invention to provide a control device for an automatic transmission for a vehicle as described above.

Means for Solving the Problems In order to achieve this object, the present invention is provided between a side for inputting and outputting a rotational force from a power source a, as shown in FIG. An automatic transmission for a vehicle including a one-way clutch b locked when the rotation speed is higher than the output side and an emblem friction element c for generating an engine brake, which is arranged in parallel with the one-way clutch b, has a throttle opening. Step-down shift detection means d for detecting a downshift accompanying an increase in the degree; receiving a detection signal from the step-down shift detection means d,
At least the one-way clutch b is provided with an emblem fastening means e for starting engagement of the emblem friction element c before the rotation speeds on the input side and the output side become the same.

According to the control device for an automatic transmission for a vehicle of the present invention having the above-described configuration, at the time of a step-down shift performed by increasing the throttle opening, the step-down shift detection means e detects this, and at least the one-way clutch b Before the rotational speeds on the input side and the output side of the engine become equal, the emblem friction element c is fastened, and at that time, the rotation on the drive wheel side is input to the power source a via the emblem friction element c. The source a is accelerated by the rotation of the driving wheel side to increase the rotation speed.
At this point, although the vehicle speed is temporarily reduced by the action of the engine brake, the vehicle acceleration is started immediately, so the time from the start of increasing the throttle opening to the start of acceleration of the vehicle is reduced, and when the downshift is performed. The acceleration feeling and response are improved.

Embodiment Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.

FIG. 2 is a schematic view of a control device for an automatic transmission according to an embodiment of the present invention. Reference numeral 10 denotes a control unit as a control device, which is controlled by a control signal output from the control unit 10. 1 is performed.

The automatic transmission 1 has, for example, a power train shown in FIG. 3, and is coupled to an engine 3 as a power source via a torque converter 2, and the rotation of the engine 3 is controlled by the torque converter 2 and the automatic transmission 1 Is output to the drive wheel side (not shown) via the

The power train of the automatic transmission 1 includes a front sun gear 12s, a front pinion gear 12p, a front internal gear 12i, and a front planet carrier 12c.
And a rear planetary gear set 14 composed of a rear sun gear 14s, a rear pinion gear 14p, a rear internal gear 14i, and a rear planet carrier 14c. Have been.

As shown in the figure, the power train has a reverse clutch R / C connecting the input shaft 16 and the front sun gear 12s, and a high clutch H / C connecting the input shaft 22 and the front planet carrier 12c.
C, forward clutch F / C connecting front planet carrier 12c and rear internal gear 14i, brake band B fixing front sun gear 12s to the housing side
/ B, and a friction element such as a low and reverse brake L & R / B for fixing the front planet carrier 12c to the housing side.

Further, a forward one-way clutch F / O is connected between the forward clutch F / C and the rear internal gear 14i.
C is provided and the front planet carrier 12
Row one way clutch L / O ・ C between c and housing
Is provided, and an overrun clutch ORC as an emblem friction element is arranged between the front planet carrier 12c and the rear internal gear 14i in parallel with the forward one-way clutch F / OC.

By the way, in the power train having such a configuration, various speeds can be obtained by engaging and releasing various friction elements as shown in Table 1 below.

In the table, a circle indicates a fastened state, and a blank indicates a released state.

In addition, the forward one-way clutch F / O ・ C
Means that the rear internal gear 14i is free with respect to the front planet carrier 12c when rotating in the forward direction and locked when rotating in the reverse direction, that is, the input-side rotational speed of the automatic transmission 12 is larger than the output-side rotational speed. It is supposed to be locked in case.

On the other hand, the low one-way clutch L / O.C is free when the front planet carrier 12c rotates in the forward direction, and locked when the front planet carrier 12c rotates in the reverse direction.

By the way, the overrun clutch O / R / C is the first
Although not shown in the table, the overrun clutch OR
By engaging C, the function of the forward one-way clutch F / OC is eliminated, the front planet carrier 12c and the rear internal gear 14i are fixed in a connected state, and the input side and the output side of the automatic transmission 12 are connected. Is directly connected to
The engine brake is activated.

FIG. 4 shows a hydraulic control circuit for controlling the hydraulic pressure supplied to each of the friction elements, and the friction elements are fastened or released by the control hydraulic pressure supplied from the hydraulic control circuit.

That is, in the hydraulic control circuit, the pressure regulator valve 20, the pressure modifier valve 22, the line pressure solenoid
24, pilot valve 26, torque converter regulator valve 2
8, lock-up control valve 30, shuttle valve 32, lock-up solenoid 34, manual valve 36, first shift valve 38,
2nd shift valve 40, 1st shift solenoid 42, 2nd shift solenoid 44, forward clutch control valve 46, 3-
2 timing valve 48, 4-2 relay valve 50, 4-2 sequence valve
52, I range pressure reducing valve 54, shuttle valve 56, overrun clutch control valve 58, third shift solenoid 60, overrun clutch pressure reducing valve 62, 2nd speed servo apply pressure accumulator 64, 3rd speed servo release pressure accumulator 66, 4th speed A servo apply pressure accumulator 68 and an accumulator control valve 70 are provided.

The respective components of the hydraulic control circuit have the relationship shown in the drawing, and the reverse clutch R / C and the high clutch H /
C, forward clutch F / C, brake band B / B, low and reverse brake L & R / B, overrun clutch O
Supplying and stopping hydraulic pressure to each friction element is performed by switching combination of the first shift valve 38 and the second shift valve 40, which is connected to each friction element of the R / C and the oil pump O / P.

The detailed configuration and function of each component of the hydraulic control circuit are the same as those described in JP-A-62-62047, and a detailed description thereof will be omitted.

Incidentally, the band brake B / B is operated by a band servo B / S shown in the drawing, and the band servo B / S is a second speed servo apply pressure chamber 2S / A and a third speed servo release pressure chamber 3S / R. And the 4th-speed servo apply pressure chamber 4S / A. The hydraulic pressure is supplied to the 2nd-speed servo apply pressure chamber 2S / A, so that the bunt brake B / B is engaged. In this state, the 3rd-speed servo release pressure chamber 3S Bunt brake B / B is released by supplying the hydraulic pressure to / R, and in this state, the bunt brake is supplied by supplying the hydraulic pressure to the 4-speed servo apply pressure chamber 4S / A.
B / B is structured to be concluded.

The switching of the first and second shift valves 38 and 40 is performed by turning on and off the first and second shift solenoids 42 and 44. When the first and second shift solenoids 42 and 44 are turned on, the first and second shift valves 38 and 40 are switched to pilot. The pressure is supplied to the right half position (upper position) in the figure, and when OFF, the pilot pressure is drained to
The second shift valves 38, 40 are at the left half position (lower position) in the figure.

As shown in Table 2 below, the first and second shift valves 38 and 40 are switched on and off according to each shift speed.

By the way, the drive signals to the first and second shift solenoids 42 and 44 are output from the control unit 10 as shown in FIG.

That is, a throttle opening (TH) signal detected by the throttle sensor 80 and a vehicle speed signal (V) detected by the vehicle speed sensor 82 are input to the control unit 10 as vehicle operating conditions. The signal is input to a shift determination circuit 84 incorporated in the control unit 10, and the shift determination circuit 84 determines a shift according to a shift schedule A stored in advance, and the determination result is output to a shift control circuit 86. Thus, the first and second shift control circuits 86
ON / OFF signals are output to the second shift solenoids 42 and 44.

By the way, the overrun clutch O / R / C for generating the engine brake is turned on and off of the third shift solenoid 60.
It is to be fastened and released by F.

That is, the third shift solenoid 60 is connected to the overrun clutch control valve 58 via the shuttle valve 56 as shown in FIG. 4, and is used for generating the switching pressure of the overrun clutch control valve 58.

The third shift solenoid 60 is driven by an ON / OFF signal output from the control unit 10 and, when OFF, drains the pilot pressure generated by the pilot valve 26 to move the overrun clutch control valve 58 to the left in the figure. It is set to the half position, and the D range pressure of the manual valve 36 is supplied to the overrun clutch O / R / C via the overrun clutch pressure reducing valve 62 so that it can be engaged.

On the other hand, when the third shift solenoid 60 is turned on, the pilot pressure can be supplied to the overrun clutch control valve 58, and the overrun clutch control valve 58 is set to the right half position in FIG. The range pressure is shut off and the overrun clutch O
-R / C is released.

By the way, the determination of engagement / disengagement of the overrun clutch O / R / C is made by a throttle opening degree change rate calculation circuit 9 built in the control unit 10 shown in FIG.
0, the determination is made by the emblem clutch necessity determining means 92 and the emblem clutch control circuit 94.

That is, the TH signal from the throttle sensor 80 is input to the throttle opening degree change rate calculation circuit 90, and the change rate ▲ ▼ is calculated based on the TH signal, and is output to the engine clutch necessity determination circuit 92. Clutch necessity judgment circuit
Reference numeral 92 denotes the ▲ ▼ signal and the signal from the throttle sensor 80.
It is determined whether engine braking is necessary by comparing with the TH signal.

Note that the emblem clutch necessity determination circuit 92 is looked up based on the limit throttle speed table B.

When it is determined by the engine braking necessity determination circuit 92 that the engine brake is necessary, the third shift solenoid 60 is output from the engine braking control circuit 94.
, And an overrun clutch O / R / C as an emblem friction element is engaged.

In this embodiment, the shift determination circuit 84 is used as a step-down downshift detecting means, and the shift mode determined from the shift schedule A is a step-down downshift, that is, a downshift due to an increase in throttle opening. ,
In this case, the downshift signal is output to the emblem clutch necessity determination circuit 92, and a signal for engaging the overrun clutch O / R / C is output to the emblem clutch control circuit 94 as the emblem engagement means. It is.

FIG. 5 shows a flow of control performed by the control unit 10. First, at step I, the throttle sensor
From the detection signal TH of 80 reads a first throttle opening degree TH _1, counts the sample time Δt of TH in the next step II.

In step III, the TH sensor 80
Signals from loading the second throttle opening degree TH _2, reads the vehicle speed V from the vehicle speed sensor 82 in the next step IV.

Then, in step V, the shift schedule A is read, and in step VI, the shift schedule A and the TH
_{Based on the two} signals and the V signal, it is determined whether a downshift is performed.

If the determination in step VI is NO, the process returns to step I again, and if the determination is YES, step VII
Then, the rate of change of the throttle opening TH is calculated.

The change rate 率 can be obtained by に よ っ て = (TH ₂ −TH ₁ ) / Δt.

Next, in step VIII, the rate of change of the limit throttle opening is read from the limit throttle opening table B, and in step IX, the 演算 calculated in step VII is equal to the predetermined value obtained from the limit throttle opening table B. It is determined whether it is larger, and if NO, the process proceeds to step X to output an ON signal to the third shift solenoid 60,
If YES, proceed to step XI to shift the third shift solenoid 6
An OFF signal is output to 0 for a predetermined time, and the overrun clutch O / R / C is engaged.

Accordingly, by the engagement of the overrun clutch O / R / C, the function of the forward one-way clutch F / O / C of the power train shown in FIG. 3 is stopped, and the input side of the automatic transmission is stopped. And the output side are directly connected.

The predetermined time during which the OFF signal is output in step XI is when the overrun clutch O / R / C is not engaged and is in the released state, and the forward one-way clutch F / OC is automatically locked. It may be determined in consideration of the rise time of the engine speed until the start.

As described above, in the control device for the automatic transmission according to the present embodiment, in the case of a step-down shift, the overrun clutch O / R / C for the engine brake is engaged, so that the automatic transmission is controlled. The rotational force of the drive wheels input from the output side accelerates the increase in engine speed at the beginning of shifting, and at this point, the vehicle is once decelerated by the action of the engine brake, but immediately after that, the vehicle starts accelerating Therefore, the time from the start of the throttle opening increase to the start of the acceleration of the vehicle is shortened, and the acceleration feeling and response at the time of the step-down shift are improved.

For example, at the time of the downshift from the fourth speed to the third speed, the operation is performed by switching the brake band B / B from the engaged state to the released state as shown in Table 1, and the release of the brake band B / B is performed. Is the 4-speed servo apply pressure (4S / A
Pressure).

By the way, in the related art, the overrun clutch O / R / C is not engaged, and the above
Since the downshift was performed by releasing the 4S / A pressure, the rise of the engine speed Ne rises with a gentle slope as shown in FIG. 8 (b), and the vehicle has the acceleration lag L shown in FIG. After that, acceleration will start.

On the other hand, in this embodiment, as shown in FIG. 6 (a), the overrun clutch OR
/ C engagement pressure (OR-C pressure) starts to be supplied, and when the OR-C pressure reaches a predetermined pressure, the overrun clutch OR-R / C is engaged. From the time point '), the rise of the engine speed rises with a steep slope. Further, immediately after the overrun clutch OR is engaged, the output torque T ₀ temporarily becomes 0 or less because the engine-side rotation speed is lower than the wheel-side rotation speed. Immediately after this, the increase starts with the increase in the engine torque, and the acceleration of the vehicle also starts at the time of the lag L at which the output torque T ₀ becomes ₀ again. Therefore, the acceleration lag L is shortened, and the acceleration feeling and the response can be improved accordingly.

In a downshift without depression, that is, a downshift due to a decrease in vehicle speed due to a release of the accelerator pedal, there is no need to wait for an increase in engine speed.
Since the overrun clutch O / R / C is not engaged, a smooth shift can be performed.

Effect of the Invention As described above, in the control device for a vehicle automatic transmission according to the present invention, at the time of a step-down shift accompanying an increase in the throttle opening, an emblem friction element for generating an engine brake is provided at least by a one-way clutch. Since the engagement is started before the input and output speeds are equal, the engine speed is accelerated by the torque input from the drive wheels in reverse, and the engine speed at the start of gear shifting can be increased. As the acceleration is accelerated, the acceleration of the vehicle is started immediately after the engagement of the emblem friction element is started, so that the time from the start of the throttle opening increase to the start of the acceleration of the vehicle is shortened,
This provides an excellent effect that the acceleration feeling and the response can be remarkably improved during the downshift.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing the concept of the present invention, FIG. 2 is a schematic diagram showing one embodiment of the present invention, and FIG. 3 is a schematic diagram showing a power train of an automatic transmission to which the present invention is applied. Figure,
FIG. 4 is a schematic configuration diagram showing a hydraulic pressure control circuit of an automatic transmission to which the present invention is applied, FIG. 5 is a flowchart showing one processing example for executing the control of the present invention, and FIG. FIG. 7 is an explanatory diagram showing an embodiment of each characteristic of the friction element fastening pressure, engine speed and output torque achieved in FIG. 7, FIG. 7 is an explanatory diagram of a conventional shift schedule, and FIG. 8 is achieved by a conventional automatic transmission. FIG. 7 is an explanatory view corresponding to FIG. DESCRIPTION OF SYMBOLS 1 ... Automatic transmission, 2 ... Torque converter, 3 ... Engine, 10 ... Control unit, 80 ... Throttle sensor, 82 ... Vehicle speed sensor, 84 ... Shift determination circuit (step-down shift detection means), 94: Emble clutch control circuit (Emble fastening means), O / R / C: Overrun clutch (Emble friction element), F / O / C: Forward one-way clutch (One-way clutch)

Claims (1)

(57) [Claims] A one-way clutch provided between a side for inputting a rotational force from a power source and a side for outputting the rotational force, the one-way clutch being locked when the rotational speed of the input side is higher than that of the output side; In an automatic transmission for a vehicle, which is arranged in a parallel relationship and has an emblem friction element for generating an engine brake, a step-down downshift detecting means for detecting a downshift accompanying an increase in a throttle opening, and the step-down downshift detecting means The automatic transmission for a vehicle further comprising: an engagement engagement means for starting engagement of the engagement friction element before at least the rotation speeds of the input side and the output side of the one-way clutch become equal in response to the detection signal of the one-way clutch. Machine control device.