JP2002130455A - Hydraulic control device for automatic transmission - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce a shift shock by maintaining a freely rotating state of a shift mechanism at down-shift time, and to finish hydraulic control of a driving force transmitting or engaging side frictional engaging element with a very small change in input shaft rotating acceleration as an index. SOLUTION: In maintaining the freely rotating state according to a down shift, when advancing a shift in an auxiliary shift mechanism by leaving a main shift mechanism as it is, a very small change is caused in the input shaft rotating acceleration ΔN. Then, an engaging state of the engaging side frictional engaging element B5 is detected with the fact of becoming almost 0 in the input shaft rotating acceleration ΔN as an index, and control of hydraulic pressure PC of a driving force transmitting frictional engaging element B1 and hydraulic pressure PB of the engaging side frictional engaging element B5 is finished. Thus, the finish can be controlled according to a fluctuation in the engaging timing.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydraulic control device for an automatic transmission mounted on an automobile, and more particularly to a hydraulic control device for downshifting.

[0002]

2. Description of the Related Art Generally, in an automatic transmission composed of a main transmission mechanism and an auxiliary transmission mechanism, when the main transmission mechanism is in a gear position intervening a one-way clutch and the auxiliary transmission mechanism is downshifted to shift gears. In particular, when downshifting in a power-off state in order to stop the vehicle, a brake arranged in parallel with the one-way clutch is operated so as not to cause a free rotation state by the one-way clutch.

When a downshift is performed in a region (power-on region) in which the speed of the input shaft (turbine shaft) is lower than the idle speed of the engine due to a decrease in the vehicle speed, a pole smaller than the idle speed is used. At the time of low vehicle speed, the friction engagement element for the downshift is exchanged, so that the difference between the engine rotation speed and the input shaft rotation speed is large, so that the torque increases in a short time and is pushed forward of the vehicle. It gives a sense of incongruity.

As a method for preventing the occurrence of the above-mentioned uncomfortable feeling,
Japanese Unexamined Patent Application Publication No. 9-21462 proposes the one disclosed. In an automatic transmission having a main transmission mechanism and an auxiliary transmission mechanism, a friction engagement element that engages at a high speed side of the main transmission mechanism is released and a friction engagement element that engages at a low speed side is used. When the main transmission mechanism engages and performs a downshift, the vehicle speed at which the shift is started is changed to a higher speed side, and a friction engagement element (brake) arranged in parallel with the one-way clutch in the auxiliary transmission mechanism Is released prior to the gripping of the friction engagement element of the main transmission mechanism,
The output shaft is brought into a free rotation state, and in this state, the main transmission mechanism is grasped and downshifted, and the turbine shaft (input shaft) rotation speed based on the downshifted gear is lower than the actual turbine shaft rotation speed. At this point in time, the one-way clutch is operated, and thereafter, the friction engagement element of the sub-transmission mechanism, which is provided in parallel with the one-way clutch, is engaged.

[0005] Accordingly, what is disclosed in the above publication is as follows.
Since the downshift is performed in the free rotation state of the output shaft, a sudden change in torque does not occur during the downshift, and the downshift is smoothly performed by the one-way clutch without giving an uncomfortable feeling that the vehicle is pushed out. A shift can be achieved.

[0006]

In the above prior art, a one-way clutch is interposed at the time of downshifting to a predetermined gear, so that the continuous pulling of the input shaft and the output shaft is interrupted and the free rotation state is established. As a result, the change in the input shaft rotation speed becomes very small, and it is not possible to perform the stroke reducing operation for the frictional engagement element on the engagement side using the change as an index, that is, the stroke learning operation relating to the servo activation control with high accuracy. Therefore, when a power-on shift-down shift or a manual shift-down shift using the engagement-side friction engagement element occurs, tie-up or engine blowing may occur.

In order to perform stroke learning with high accuracy, if the input shaft and the output shaft are kept connected by a frictional engagement element, the shift shock and the engine braking feeling accompanying the clutch re-engagement described above may occur. Occurs and is not preferred.

Accordingly, the present invention aims to reduce shift shock by maintaining the free rotation state of the transmission mechanism at the time of a downshift, and to use a small change in the input shaft rotational acceleration as an index to transmit frictional force for transmitting driving force. It is an object of the present invention to provide a hydraulic control device for an automatic transmission in which an element is disconnected and the engagement of an engagement-side friction engagement element is terminated.

[0009]

According to the present invention, an input shaft (3) to which power from an engine output shaft (13) is input, an output shaft (6) connected to wheels, A plurality of friction engagement elements (C1 to C3, B1 to B) for changing a power transmission path between the input shaft (3) and the output shaft (5).
5), a hydraulic servo (29, 30, 37) for disconnecting and engaging the frictional engagement element, and hydraulic control means (SLS,
SLU, SLT) and a control unit (21) for outputting a hydraulic control signal to the hydraulic control means, the control unit (21) comprising: Upon shifting, the frictional engagement element (B
Release side control means (21) for controlling the hydraulic pressure (P _A ) of 4)
a), engagement side control means (21b) for controlling the oil pressure (P _B ) of the engagement side frictional engagement element (B5) at the time of downshifting to the predetermined speed, and downshifting to the predetermined speed. Input shaft rotation acceleration detection means (21f) for detecting an input shaft rotation acceleration (ΔN) associated with a shift, wherein the control unit (21) comprises:
and f) determining the start or end of the shift in the downshift based on the input shaft rotational acceleration (ΔN) detected in f).

According to a second aspect of the present invention, the control section (2
1) determining that the shift start in the downshift is started based on the fact that the input shaft rotational acceleration (ΔN) detected by the input shaft rotational acceleration detecting means (21f) is substantially equal to or greater than 0. The hydraulic control device for an automatic transmission according to claim 1, wherein:

According to a third aspect of the present invention, the control section (2
1) determining the end of the shift in the downshift based on the fact that the input shaft rotational acceleration (ΔN) detected by the input shaft rotational acceleration detection means (21f) is substantially equal to or less than 0. The hydraulic control device for an automatic transmission according to claim 1 or 2, wherein:

According to a fourth aspect of the present invention, the engagement-side control means (21b) has a servo start control and a completion control, and ends the servo start control based on judging the start of the shift. 4. The hydraulic control device for an automatic transmission according to claim 1, wherein said completion control is started, and said completion control is ended based on judging the end of said shift. .

According to a fifth aspect of the present invention, the input shaft rotational acceleration detecting means (21f) includes a rotational change acceleration (ΔN).
5. The method according to claim 1, wherein a value of approximately 0 or more or approximately 0 or less is detected based on integrating the sum of
The hydraulic control device for an automatic transmission according to any one of the above.

According to a sixth aspect of the present invention, the input shaft rotational acceleration detecting means (21f) counts based on the fact that the input shaft rotational acceleration (ΔN) is approximately 0 or more or approximately 0 or less. (For example, C1, C2) is started, and the count (for example, C1, C2) is increased by a predetermined amount (for example, t1, t2).
The hydraulic control device for an automatic transmission according to any one of claims 1 to 4, wherein a start or an end of a shift in the downshift is determined based on reaching (2).

According to a seventh aspect of the present invention, the predetermined gear stage is provided.
One-way clutch (F1) when downshifting to
Of the frictional engagement element (B1) for transmitting the driving force which is provided in parallel with
(P _C) To control the input shaft (3) and the output shaft (6).
During the downshift.
Driving force transmission control that controls the torque input from the engine
Means (21e) and the downshift to the predetermined gear position.
In this case, the gear shifting until the shift accompanying the downshift is started
Input shaft by the driving force transmission control means (21e)
Maintaining the connection between (3) and the output shaft (6),
A shift progress control means (2) for controlling the connection state to be disconnected.
1c).
6. The hydraulic control device for an automatic transmission according to any one of the above items 6.

According to the present invention, an input shaft (3) and an output shaft (6) are controlled by the driving force transmission control means (21e).
While the connection state is maintained, the stroke learning control when the backlash of the hydraulic servo of the engagement side frictional engagement element (B5) is reduced is performed based on the rotation state of the input shaft (3). The hydraulic control device for an automatic transmission according to claim 7, further comprising a learning control means (21d).

According to a ninth aspect of the present invention, the transmission mechanism (1) comprises a main transmission mechanism (2) and an auxiliary transmission mechanism (5). The hydraulic control device for an automatic transmission according to any one of the preceding claims.

According to a tenth aspect of the present invention, in the downshift to the predetermined gear, the shift progress control means (21c) transmits the driving force until the shift associated with the downshift is started. The control means (21e) drives and controls the frictional engagement element (B1) for transmitting the driving force at a standby engagement pressure (Pw ′) at which the engagement can be maintained to the extent that slip does not occur. A hydraulic control device for an automatic transmission according to claim 7.

The reference numerals in parentheses are for the purpose of comparison with the drawings, but do not affect the structure of the claims.

[0020]

According to the first aspect of the present invention, the input shaft rotational acceleration is detected by the input shaft rotational acceleration detecting means at the time of downshifting to a predetermined gear, so that the input shaft rotational acceleration is used as an index. Thus, the control of the hydraulic pressure of the frictional engagement element for transmitting the driving force or the engagement side can be started or ended. Thus, the shift can be started or ended in accordance with the variation in the engagement timing, so that useless time for responding to the variation can be eliminated, and shift shock accompanying a downshift can be reduced.

According to the second aspect of the present invention, the input shaft rotational acceleration is detected by the input shaft rotational acceleration detecting means, and when the input shaft rotational acceleration becomes substantially equal to or greater than 0, the speed is reduced to a predetermined gear position. The start of the shift in the shift can be determined. As a result, it is possible to eliminate wasted time for responding to the variation and reduce shift shock accompanying downshifting.

According to the third aspect of the present invention, the input shaft rotational acceleration is detected by the input shaft rotational acceleration detecting means, and when the input shaft rotational acceleration becomes substantially 0 or less, the speed is reduced to a predetermined gear position. The end of the shift in the shift can be determined. As a result, it is possible to eliminate wasted time for responding to the variation and reduce shift shock accompanying downshifting.

According to the fourth aspect of the present invention, the engagement control means terminates the servo activation control and starts the completion control based on the determination of the shift start, and determines the end of the shift. Since the completion control is terminated based on
The shift can be started and ended according to the variation in the engagement timing, so that useless time for responding to the variation can be eliminated, and shift shock accompanying a downshift can be reduced.

According to the fifth aspect of the present invention, the input shaft rotational acceleration detecting means integrates the sum of the input shaft rotational accelerations,
Since approximately 0 or more or approximately 0 or less is detected, for example, even if the value of the input shaft rotational acceleration that causes fluctuation due to noise or the like becomes erroneously 0 or more or less than 0, it is related to malfunction. It is possible to prevent starting or ending the control of the oil pressure of the mating friction engagement element, that is, to start or end the control at an appropriate timing.

According to the sixth aspect of the present invention, the input shaft rotational acceleration detecting means starts counting based on the input shaft rotational acceleration being substantially equal to or greater than 0 or substantially equal to or less than 0,
Since the start or end of the shift is determined based on the count reaching a predetermined amount, the value of the input shaft rotational acceleration that causes fluctuation due to noise or the like may be erroneously set to 0 or more or 0 or less. However, it is possible to prevent the control of the hydraulic pressure of the frictional engagement element on the engagement side from starting or ending due to a malfunction, that is, to start or end the control at an appropriate timing.

According to the seventh aspect of the present invention, when a downshift to a predetermined gear is performed, the connection between the input shaft and the output shaft is controlled by the driving force transmission control unit until the shift associated with the downshift is started. Since the state is maintained, the shift start control using the input shaft rotation speed as an index can be performed as in the related art. Thereafter, the shift progress control means disconnects the connection state between the input shaft and the output shaft, and sets the transmission mechanism in a free rotation state in order to reduce shift shock. , So
The input shaft rotation acceleration can be used as an index, and control of the hydraulic pressure of the frictional engagement element on the engagement side can be started or ended. Thus, the start or end of the shift corresponding to the variation in the engagement timing can be performed, so that a useless time for responding to the variation can be eliminated, and the shift shock accompanying the downshift can be reduced.

According to the present invention, while the learning control means maintains the connection state between the input shaft and the output shaft by the driving force transmission control means, the frictional engagement element on the engagement side is maintained. Stroke learning control during backlash in hydraulic servo can be performed based on the rotation state of the input shaft, and the rotation state of the input shaft is used as an index despite the appearance of the free rotation state of the transmission mechanism during downshifting. Highly accurate stroke learning can be performed. Further, in the initial state before learning, the start of engagement of the frictional engagement element on the engagement side varies due to the stroke at the time of loosening, but it is determined based on the input shaft rotation acceleration that the transmission of the driving force or the engagement is performed. Since the hydraulic pressure of the frictional engagement element on the mating side is controlled, it is possible to prevent the occurrence of a shift shock due to a variation in the engagement timing.

According to the ninth aspect of the present invention, the speed change mechanism comprises the main speed change mechanism and the sub speed change mechanism. When the speed change mechanism is in a free rotation state, the speed change of the sub speed change mechanism causes the main speed change. Since a slight change occurs in the input shaft rotation acceleration of the mechanism, the change in the input shaft rotation acceleration can be used as an index.

According to the tenth aspect of the present invention, the frictional engagement element of the driving force transmission control means can maintain the engagement to such an extent that no slippage occurs until the shift associated with the downshift is started. Since the drive control is performed by the standby engagement pressure, the subsequent release operation of the friction engagement element can be performed in a short time, and the downshift time can be reduced.

[0030]

Embodiments of the present invention will be described below with reference to the drawings. The five-speed automatic transmission 1 is shown in FIG.
As shown in the figure, the vehicle includes a torque converter 4, a three-speed main transmission mechanism 2, a three-speed auxiliary transmission mechanism 5, and a differential 8, and these parts are housed in a case integrally connected to each other. . The torque converter 4 includes a lock-up clutch 4a, and the engine is rotated from the engine crankshaft 13 via an oil flow in the torque converter or via a mechanical connection by the lock-up clutch. Is input to the input shaft 3. The first shaft 3 (specifically, the input shaft) arranged in alignment with the crankshaft and the second shaft 6 (counter shaft) and the third shaft
Shafts (left and right axles) 14a and 14b are rotatably supported, and a valve body is disposed outside the case.

The main transmission mechanism 2 has a planetary gear unit 15 composed of a simple planetary gear 7 and a double pinion planetary gear 9. The simple planetary gear 7 is a carrier that supports a sun gear S1, a ring gear R1, and a pinion P1 meshing with these gears. The double pinion planetary gear 9 is composed of a sun gear S2, a ring gear R2, and a pinion P2 meshing with the sun gear S2 and a pinion P3 meshing with the ring gear R2 together with the pinion P1 of the simple planetary gear 7 having a different number of teeth from the sun gear S1. It consists of a supporting common carrier CR.

The input shaft 3 linked from the engine crankshaft 13 via the torque converter 4
Can be connected to the ring gear R1 of the simple planetary gear 7 via the first (forward) clutch C1, and can be connected to the sun gear S1 of the simple planetary gear 7 via the second (direct) clutch C2. The sun gear S2 of the double pinion planetary gear 9
Can be directly locked by the first brake B1, and can be locked via the first one-way clutch F1.
It can be locked at 2. Furthermore, the ring gear R2 of the double pinion planetary gear 9 is connected to the third brake B3 and the second gear B2.
Can be locked by the one-way clutch F2. Further, the common carrier CR is connected to a counter drive gear 18 serving as an output member of the main transmission mechanism 2.

On the other hand, the auxiliary transmission mechanism 5 moves the output gear 1 toward the rear side in the axial direction of the counter shaft 6 constituting the second shaft.
6, a first simple planetary gear 10 and a second simple planetary gear 11 are arranged in this order, and the counter shaft 6 is rotatably supported by an integrated case via a bearing. The first and second simple planetary gears 10, 11 are of Simpson type.

Also, the first simple planetary gear 10
Means that the ring gear R3 is the counter drive gear 1
The sun gear S3 is fixed to a sleeve shaft 12 rotatably supported on the counter shaft 6 with the counter driven gear 17 meshing with the counter driven gear 17. And
The pinion P3 is supported by a carrier CR3 formed of a flange integrally connected to the counter shaft 6, and the carrier CR3 supporting the other end of the pinion P3 is connected to an inner hub of the UD direct clutch C3. The second simple planetary gear 11 has a sun gear S4 formed on the sleeve shaft 12 and is connected to the sun gear S3 of the first simple planetary gear. The ring gear R4 is connected to the counter shaft 6. .

The UD direct clutch C3 is
The sun gears S3 and S4 are interposed between the carrier CR3 of the first simple planetary gear and the connected sun gears S3 and S4, and the connected sun gears S3 and S4 are engaged by a fourth brake B4 including a band brake. Can stop. Further, the carrier CR4 supporting the pinion P4 of the second simple planetary gear can be locked by the fifth brake B5.

Next, the operation of the mechanism of the present five-speed automatic transmission will be described with reference to FIGS.

The first speed (1S) in the D (drive) range
In the T) state, the forward clutch C1 is engaged, and the fifth brake B5 and the second one-way clutch F2
And the ring gear R2 of the double pinion planetary gear and the carrier CR4 of the second simple planetary gear 11 are held in a stopped state. In this state, the rotation of the input shaft 3 is transmitted to the ring gear R1 of the simple planetary gear via the forward clutch C1, and the ring gear R2 of the double pinion planetary gear is in a stopped state, so that the two sun gears S1 and S2 idle in the opposite direction. While doing so, the common carrier CR is largely decelerated and rotated in the forward direction. That is, the main transmission mechanism 2 is in the first speed state, and the reduced rotation is transmitted to the ring gear R3 of the first simple planetary gear in the auxiliary transmission mechanism 5 via the counter gears 18 and 17. The auxiliary transmission mechanism 5 is in the first speed state with the carrier CR4 of the second simple planetary gear stopped by the fifth brake B5, and the reduced speed rotation of the main transmission mechanism 2 is further reduced by the auxiliary transmission mechanism 5. Output from the output gear 16.

In the second speed (2ND) state, in addition to the forward clutch C1, the second brake B2 (and the first brake B1) operates, and further, the second one-way clutch F2 to the first one-way clutch F1 , And the fifth brake B5 is maintained in the locked state. In this state, the sun gear S2 is set to the second brake B
2 and the first one-way clutch F1 is stopped,
Therefore, the rotation of the ring gear R1 of the simple planetary gear transmitted from the input shaft 3 via the forward clutch C1 corresponds to the rotation of the ring gear R2 of the double pinion planetary gear.
The carrier CR is decelerated in the forward direction while idling in the forward direction. Further, the deceleration rotation is performed by the counter gears 18, 1
The transmission is transmitted to the auxiliary transmission mechanism 5 via the transmission 7. That is, the main speed change mechanism 2 is in the second speed state, and the auxiliary speed change mechanism 5 is in the first speed state by engagement of the fifth brake B5.
By combining the speed states, the second speed can be obtained in the entire automatic transmission 1. Note that, at this time, the first brake B1 is also operated, but when the second speed is set due to the coast down, control is performed as described later.

In the third speed (3RD) state, the forward clutch C1, the second brake B2, the first one-way clutch F1, and the first brake B1 are kept in the engaged state, and the fifth brake B5 is locked. Is released and the fourth brake B4 is engaged. That is, the main transmission mechanism 2 is kept in the same state, the above-mentioned rotation at the second speed is transmitted to the sub transmission mechanism 5 via the counter gears 18 and 17, and the sub transmission mechanism 5 performs the first simple transmission. The rotation of the planetary gear from the ring gear R3 is output from the carrier CR3 as a second-speed rotation by fixing the sun gear S3 and the sun gear S4. The third speed is obtained.

In the fourth speed (4TH) state, the main transmission mechanism 2
Are the forward clutch C1, the second brake B2, the first one-way clutch F1, and the first brake B
This is the same as the above-described second speed and third speed states in which the first gear 1 is engaged, and the auxiliary transmission mechanism 5 releases the fourth brake B4 and performs UD
The direct clutch C3 is engaged. In this state, the carrier CR3 of the first simple planetary gear is connected to the sun gears S3 and S4, and the planetary gears 10 and 11 are directly connected to rotate. Therefore, the second speed of the main transmission mechanism 2 and the direct connection (third speed) of the auxiliary transmission mechanism 5 are combined, and the fourth speed rotation is output from the output gear 16 in the entire automatic transmission.

In the fifth speed (5TH) state, the forward clutch C1 and the direct clutch C2 are engaged, and the rotation of the input shaft 3 rotates the ring gear R1 of the simple planetary gear.
And transmitted to the sun gear S1, the main transmission mechanism 2
Direct connection rotation in which the gear unit rotates integrally. On this occasion,
The first brake B1 is released and the second brake B2
Is held in the engaged state, but the first one-way clutch F
When the wheel 1 idles, the sun gear S2 idles. Further, the auxiliary transmission mechanism 5 is a direct connection rotation in which the UD direct clutch C3 is engaged.
The speed (direct connection) and the third speed (direct connection) of the auxiliary transmission mechanism 5 are combined, and the fifth speed rotation is output from the output gear 16 in the entire automatic transmission.

Further, the automatic transmission has an intermediate shift stage that operates during a downshift such as acceleration, that is, a third-speed low and a fourth-speed low.

In the third gear low state, the forward clutch C1
And the direct clutch C2 is connected (the second brake B
2 is in the engaged state, but overruns due to the one-way clutch F1), and the main transmission mechanism 2 is in the third speed state in which the planetary gear unit 15 is directly connected. On the other hand, the fifth brake B5 is locked, and the auxiliary transmission mechanism 5 is in the first speed state. Therefore, the third speed state of the main transmission mechanism 2 and the first speed state of the auxiliary transmission mechanism 5 are combined, and the automatic transmission 1 As a whole, a gear stage having a gear ratio between the second and third speeds described above is obtained.

The fourth speed low state corresponds to the forward clutch C1.
And the direct clutch C2 is connected to the main transmission mechanism 2
Is in the third speed (direct connection) state as in the third speed low state. On the other hand, when the fourth brake B4 is engaged, the sun gear S of the first simple planetary gear 10
Sun gear S of third and second simple planetary gears 11
4 is fixed and in the second speed state. Therefore, the main transmission mechanism 2
The third speed state and the second speed state of the auxiliary transmission mechanism 5 are combined to obtain the above-mentioned gear ratio in the automatic transmission 1 as a whole between the third and fourth speeds.

In FIG. 3, the dotted circles indicate the operating state of the coasting engine brake (4, 3 or 2 ranges). That is, at the first speed, the third brake B3 operates to prevent the rotation of the ring gear R2 due to the overrun of the second one-way clutch F2. In the second gear, the third gear, and the fourth gear, the first brake B1 is actuated and the sun gear S1 due to the overrun of the first one-way clutch F1.
Block the rotation of

In the R (reverse) range,
The direct clutch C2 and the third brake B3 are engaged, and the fifth brake B5 is engaged. In this state, the rotation of the input shaft 3 is transmitted to the sun gear S1 via the direct clutch C2, and the ring gear R2 of the double pinion planetary gear is stopped by the third brake B3. The carrier CR also reverses while idling, and the reverse rotation is transmitted to the auxiliary transmission mechanism 5 via the counter gears 18 and 17. In the auxiliary transmission mechanism 5, the carrier CR4 of the second simple planetary gear is also stopped in the reverse rotation direction based on the fifth brake B5, and the first speed state is maintained. Therefore, the reverse rotation of the main transmission mechanism 2 and the
The high speed rotation is combined, and the output shaft 16 outputs the reverse rotation deceleration rotation.

FIG. 1 is a block diagram showing an electric control system. Reference numeral 21 denotes a control unit (ECU) comprising a microcomputer (microcomputer), an engine rotation sensor 22, and a throttle opening for detecting an accelerator pedal depression amount of a driver. Degree sensor 23, sensor 2 for detecting the input shaft rotation speed (= turbine rotation speed) of the transmission (automatic transmission mechanism)
5. Signals from a vehicle speed (= automatic transmission output shaft rotation speed) sensor 26 and an oil temperature sensor 27 are input, and the linear solenoid valves SLS, SLU, and SL of the hydraulic circuit are input.
Output to T. The control unit 21 controls a connection state between an input shaft and an output shaft of a transmission, which includes a release-side control unit 21a that controls a release-side hydraulic pressure, an engagement-side control unit 21b that controls an engagement-side hydraulic pressure. Driving force transmission control means 21e,
A predetermined gear (2) with a one-way clutch (F1) interposed
Speed change control means 2 for controlling the operation of each friction engagement element involved in the speed change over time when downshifting to speed
1c and learning control means for controlling stroke learning of the engagement-side friction engagement element during downshifting while the frictional engagement element for preventing idling of the one-way clutch is controlled by the driving force transmission control means 21e. 21d, and input shaft rotational acceleration detecting means 21f for detecting the rotational acceleration of the input shaft from the input shaft.

FIG. 4 is a diagram schematically showing a hydraulic circuit.
A plurality of frictional engagement elements having the three linear solenoid valves SLS, SLU, and SLT and switching the transmission path of the planetary gear unit of the automatic transmission mechanism to achieve, for example, a fifth forward speed and a first reverse speed. A plurality of hydraulic servos 29 for connecting and disconnecting clutches and brakes;
30 and 37 are provided. Also, the input ports a ₁ , a _{1 of} the linear solenoid valves SLS, SLU and SLT
The _2, a ₃ is supplied with the solenoid modulator pressure output port b ₁ of the linear solenoid valve,
The control oil pressures from b ₂ and b _{3 are applied} to the control oil chambers 31 a and 32 of the pressure control valves 31, 32 and 33, respectively.
a, 33a. The pressure control valves 31, 32, and 33 supply line pressure to input ports 31b, 32b, and 33b, respectively, and output ports 31c, 32c, and 33 that are regulated by the control hydraulic pressure.
c, the pressure-regulating oil pressure from the shift valves 34, 3
The hydraulic servos 29, 30, and 37 are supplied to the hydraulic servos 29, 30, and 37 as appropriate via the reference numerals 5 and 36.

The present hydraulic circuit shows a basic concept relating to a so-called clutch-to-clutch shift in which one friction engagement element is released and the other friction engagement element is engaged. 29, 30, 37 and the shift valves 34, 35, 36 are symbolically shown. Actually, many hydraulic servos are provided corresponding to the automatic transmission mechanism. Hydraulic servo for fourth brake B4, fifth brake B during 3 → 2 shift
Hydraulic servo for 5 and hydraulic servo for the first brake B1,
The hydraulic servo for the third clutch C3 and the hydraulic servo for the fourth brake B4 at the time of the 4 → 3 shift are provided with a number of shift valves for switching the hydraulic pressure to these hydraulic servos.

In the above-mentioned 3 → 2 downshift, the hydraulic pressure of the hydraulic servo for the fourth brake B4 is released, and the hydraulic pressure of the hydraulic servo for the fifth brake B5 is engagement-controlled. Prior to the gripping control of the two brakes, the hydraulic pressure of the hydraulic brake servo for the first brake B1 is released in a pattern described later, and is supplied after the gripping control ends and the first one-way clutch F1 is engaged. You. That is, the fourth and fifth gears in the subtransmission mechanism 5
Is basically performed in a free rotation state (neutral state) of the main transmission mechanism 2 based on the release of the first brake B1 and the first one-way clutch F1. However, the first brake B1 is held at a hydraulic pressure that does not cause the brake B1 to slip until the rotational acceleration of the input shaft changes from negative to zero. After the gripping operation of the fourth and fifth brakes B4 and B5 is completed, by depressing the accelerator,
When the rotation of the sun gear S2 switches from normal rotation to reverse rotation,
That is, when the input shaft rotation speed based on the gear ratio from the output shaft side falls below the engine rotation speed, the first one-way clutch F1 is engaged, the free rotation state is released, and the second speed stage is established. After that, the first brake B1 is engaged. Alternatively, when the vehicle speed increases on a downhill road or the like, the first one-way clutch F1 is in a free rotation state. In this case, the first brake B1 is engaged at a predetermined vehicle speed or higher.

Next, a downshift by clutch-to-clutch, for example, 3 → 2 shift will be described with reference to FIGS. 3 → 2 In the shift is specifically a release side hydraulic pressure P _A is hydraulic fourth brake B4, the engagement hydraulic pressure P _B is the fifth brake B5 hydraulic.

First, based on the signals from the throttle opening sensor 23 and the vehicle speed sensor 26, the control unit 21 determines from the map a downshift such as a 3 → 2 shift or the like. In accordance with the flowchart shown in FIG. 7, a command is issued to control the brake B5 as the engagement-side friction engagement element, the brake B4 as the release-side friction engagement element, and the brake B1 as the friction engagement element for engine brake. I do. Shift progress control means 21c
Receives this, as shown in FIGS. 7 and 8, calculates the first brake B1, that is, the brake side torque Tc for the engine brake using the function of the input torque Tt (S1).
1). The input torque Tt is obtained, for example, by calculating an engine torque based on a throttle opening and an engine speed using a map, further calculating a speed ratio from an input / output speed of the torque converter, obtaining a torque ratio from the speed ratio using a map, It is determined by multiplying the torque by the torque ratio. Furthermore,
The brake-side torque Tc is obtained by relating the input torque to the torque sharing ratio and the like.

From the brake side torque Tc, the brake B1
Side standby engagement pressure Pw 'is calculated (S12), and the release-side control means 21a outputs a control signal to the linear solenoid valve so that the hydraulic pressure of the hydraulic servo of the brake B1 becomes the standby engagement pressure Pw'. (S13). Then, the first brake B1 changes the standby engagement pressure Pw ′ from the initial engagement pressure Pc.
Down to. At the standby engagement pressure Pw ', the first brake B1 is maintained to the extent that no slip occurs. In this state, the main transmission mechanism is not yet in the neutral state, maintains the third speed state, and the release-side hydraulic pressure P _A, for example, the hydraulic pressure for the fourth brake B4 has a engagement pressure, release side Friction engagement element (for example, fourth brake B4)
Is in the engaged state.

On the other hand, as shown in FIGS. 5 and 8, with respect to the brake B4, which is a frictional engagement element on the releasing side, when a command to reduce the brake B1 to a predetermined standby engagement pressure Pw 'is issued. , The shift progress control means 21c
Perform the step S1 of calculating the release side torque _{T A} by a function of the input torque Tt (S1). The input torque T
t is, for example, an engine torque is obtained based on a throttle opening and an engine speed by a map, a speed ratio is further calculated from an input / output speed of the torque converter, and a torque ratio is obtained from the speed ratio by a map. Is multiplied by the above torque ratio. Furthermore, the release side torque T _A is required torque sharing rate such as input torque involved.

[0055] calculated waiting engagement pressure Pw release side from the release side torque T _A is (S2), the shift progress control unit 21c on the disengagement side controller 21a, the supply oil pressure該待machine engagement of the brake B4 application pressure The control signal is output to the linear solenoid valve so as to be Pw (S3). Furthermore, the shift progress control means 21c via the release-side control unit 21a, in step S4 of FIG. 5, the hydraulic [delta] P _E having a predetermined slope which is set in advance to supply hydraulic pressure P _A of the brake B4 from Pw, swept down (S4). This control is continued until the supply pressure _{P A} is 0 (S5).

On the other hand, the brake B5 on the engagement side is shown in FIG.
And FIG. 8, on the basis of the downshift determination from controller 21, shift progress control means 21c clocking is started by (S30), the hydraulic pressure P _B to the fifth brake B5 hydraulic servo predetermined pressure Ps1 A predetermined signal is output to the linear solenoid valve SLS (or SLU) so as to satisfy (S31).

[0057] said predetermined pressure Ps1 is filled hydraulic chamber of the hydraulic servo is set to hydraulic pressure required to perform the play reduction, are held for a predetermined time t _SA, the retention time will be described later In this manner, the learning control unit 21d performs the change control every time so that the learning control is performed so that the optimal time is obtained. When the predetermined time _{t SA} has passed (S32), the engagement hydraulic pressure _{P B} is a predetermined gradient [(Ps1-Ps2) /
t _SB ] (S33), and the engaging-side hydraulic pressure P
_{When B} reaches the predetermined low pressure Ps2 (S34), the sweep-down is stopped and held at the predetermined low pressure Ps2 (S3).
5). The predetermined low pressure Ps2 is equal to or higher than the piston stroke pressure and the engagement-side frictional engagement element (for example, the fifth brake B
5) is set to a pressure that generates a torque capacity, and the predetermined low pressure Ps2 is set such that the time t is measured for a predetermined time (for example, the brake B
Held from 1 after release time was in time to completion control start before the brake B5) until t _SE elapsed (S3
6). Servo start control is performed in steps S31 to S36. Here, since the predetermined low pressure Ps2 is set to a pressure that generates the torque capacity, the engagement of the engagement-side frictional engagement element (B5) starts while the predetermined low pressure Ps2 is maintained, that is, the shift is performed. Start (rotation change starts).

At this time, as shown in FIG. 8, the rotation speed of the input shaft is maintained at the standby engagement pressure Pw 'which does not cause the first brake B1 to slip, so that the main transmission mechanism 1 Since the vehicle is not in the neutral state, it is possible to accurately capture a change in the rotation speed of the input shaft caused by a decrease in the vehicle speed and an operation of releasing the brake B4.

Therefore, while monitoring the change in the input shaft rotation speed, the rotation acceleration shifts from negative to 0, and the brake B
The time T1 (start of shifting) at which the gear 5 starts the actual engagement is
The stroke adjustment of the brake B5, which is the frictional engagement element on the engagement side, can be performed by learning control so as to occur at an appropriate timing.

That is, the learning control means 21d temporarily determines that
As shown by the broken line, the rotational acceleration shifts from negative to 0,
When the actual engagement start of the brake B5 occurs at the time T2, it is determined that the stroke of the brake B5 is too early and the actual engagement is started early, and step S32 of FIG. of a predetermined time t _SA, to shorten the next operating cycle a predetermined time, excessive play elimination (thus starting the actual engagement) is corrected to so as not to cause. Further, as shown by the dashed line in FIG. 8, when the actual engagement of the brake B5 starts at the time T3, the stroke of the brake B5 is too slow and the actual engagement starts with a delay. the predetermined time t _SA in step S32 required for the play elimination, a predetermined time from the next operation cycle, is corrected so as to perform the longer sufficient play reduction operation. At this point, the transmission as a whole is in the initial stage of the gripping operation of the friction engagement elements such as the brakes B4 and B5, and substantially maintains the high speed stage such as the third speed. There is no feeling of engine braking or shift shock. Thus, the learning control of the brake B5 on the engagement side by the learning control means 21d is performed.

Here, in the present invention, for example, 3-2
When the speed change is performed, the speed change progresses in the sub speed change mechanism 5 while the main speed change mechanism 2 is maintained (see FIGS. 2 and 3). Then, a slight change occurs in the rotational speed N and the rotational acceleration ΔN of the input shaft 3 due to drag torque, internal inertia, and the like of the input shaft 3 of the main transmission mechanism 2 with the shift of the sub transmission mechanism 5. Therefore, the engagement state of the engagement side frictional engagement element B5 is detected using the input shaft rotation acceleration ΔN as an index.

As shown in FIGS. 7 and 8, the input shaft rotational acceleration detecting means 21f is provided with a T / M input shaft rotational speed sensor 25.
Input shaft rotation acceleration ΔN based on the input shaft speed signal from
Is detected to shift from negative to 0 or more (S1
4), a signal is sent to the shift progress control means 21c, and the linear solenoid valve SL is transmitted via the drive force transmission control means 21e.
S, SLU, or by operating the SLT, to release the engagement pressure _{P C} of the first brake B1 at the time X 'to 0 (S
15), the control of the first brake B1 ends. That is, the main transmission mechanism 1 is set in the neutral state, and thereafter, the vehicle is prepared for a downshift operation due to the start of engagement of the brake B5 which is the frictional engagement element on the engagement side.

By controlling the end of the first brake B1 as described above, even if the actual start of engagement of the brake B5 occurs at any of the time points T1, T2 or T3 as described above, the input is controlled. When it is detected that the rotational acceleration ΔN has shifted from negative to 0 or more, the control of the first brake B1 is terminated, and a preparation is made for a downshift operation due to the start of engagement of the brake B5 which is an engagement-side frictional engagement element. For example, it is possible to prepare for a shift operation without relying on time control by a timer. Further, even in the initial state before the learning, the engagement start determination can always be made at an appropriate timing.

On the other hand, as shown in FIG. 6, the shift progress control means 21c includes a brake B5 which is a frictional engagement element on the engagement side.
When the servo start control (to step S36 in FIG. 6) is completed (t ≧ t _SE ), the input shaft rotational acceleration detecting unit 21
When f detects that the input shaft rotation acceleration ΔN has shifted from negative to 0 or more based on the input shaft rotation speed signal from the T / M input shaft rotation speed sensor 25 (S37), the counter C1 is detected from the detected time X. Is started (S38). Since the input shaft rotation acceleration ΔN is a small value and not a stable value, but a value in which a slight fluctuation due to noise or the like occurs, for example, the input shaft rotation acceleration ΔN is set to 0 or more before or after the time X when the input becomes 0 or more. In some cases, such detection may occur, and in some cases, a malfunction may occur in which the engagement of the brake B5, which is the frictional engagement element on the engagement side, is completed at a time other than an appropriate timing. Therefore, the input shaft rotational acceleration detecting means 21
f starts the counter C1 from the time X as described above, and determines the time X 'when the counter C1 reaches the predetermined amount t1 (S39). Then, the shift progress control means 21c
, The servo start control is terminated at the time X ′, and the completion control is immediately started.

[0065] In the complete control, firstly by a hydraulic [delta] P _F is swept up of a predetermined slope which is set in advance the engagement hydraulic pressure P _B of the brake B5 (S40). When the input shaft rotation acceleration detecting means 21f detects that the input shaft rotation acceleration ΔN has shifted from positive to 0 or less based on the input shaft rotation speed signal from the T / M input shaft rotation speed sensor 25 (S41), The counter C2 starts from the time point Y when the detection is performed.
Is started (S42). As described above, the input shaft rotation acceleration ΔN is a small value, is not a stable value, and is a value in which a slight fluctuation caused by noise or the like occurs. In some cases, 0 or less may be detected before and after, and in some cases, a malfunction may occur in which the engagement of the brake B5, which is the frictional engagement element on the engagement side, is completed except at an appropriate timing. Therefore, the input shaft rotational acceleration detecting means 21f
Starts the counter C2 from the time point Y as described above, and determines the time point Y 'when the counter C2 reaches the predetermined amount t2 (S43). Then, the input shaft rotational acceleration detecting means 21f sends a signal to the shift progress control means 21c, and the linear solenoid valve S via the engagement side control means 21b.
LS, operating SLU, and the SLT, to complete the sweep-up of the engagement pressure P _B of the brake B5 at time Y ', and ends the completion control of the brake B5 is frictional engagement element on the engagement side. That is, the engagement of the brake B5 is completed and 3
→ Two shifts are completed.

By controlling the completion of the brake B5, which is the frictional engagement element on the engagement side, as described above, for example, as described above, the actual start of engagement of the brake B5 is performed at the time points T1, T2.
Or T3, the count of the counter C1 or the counter C2 is increased by the predetermined amount t1 or the predetermined amount t2.
, The completion control of the brake B5 is started or ended, so that the shift completion control can be started or ended using the input shaft rotation acceleration ΔN as an index without relying on, for example, a time control by a timer from the start of the shift. . Also,
Even in the initial state before learning, engagement start or engagement end can always be performed at appropriate timing.

In this embodiment, the engagement start or end of the brake B5 which is the frictional engagement element on the engagement side is performed based on the counter C1 or the counter C2.
The engagement start or the engagement end may be performed based on the total of the rotational accelerations reaching a predetermined value or more.

At this time, as described above, since the brake B1 which is the frictional engagement element for the engine brake is released, the main transmission mechanism 1 is in the neutral state even when the brake B5 is engaged. As a result, since the torque from the engine side is cut off, the occurrence of a shift shock in which the vehicle is pushed out due to the engagement of the brake B5 is prevented.

As described above, according to the present invention, the start or end of engagement can be always detected at an appropriate timing. Therefore, even if the actual start of engagement varies in the initial state before learning, the shift shock can be detected. Can be downshifted without the occurrence of. Further, for example, in the time control by the timer, it was necessary to set the time required for the engagement end to be the longest time for all cases. By doing so, wasted time can be eliminated, and the shift control can be terminated in accordance with the variation in the actual start of engagement (for example, at times T1, T2, T3) or the variation in the end of engagement.

The input shaft rotation acceleration Δ
Since the engagement start and the engagement end are performed based on N, it is possible to prevent a malfunction due to the fluctuation of the input shaft rotational acceleration ΔN due to noise or the like.

In the 3 → 2 shift by the clutch-to-clutch (change of clutch), the first brake B1 is released when the rotational acceleration ΔN of the input shaft rotational speed substantially starts to become 0 or more. Also, after the completion of the completion control in step S40, that is, after the completion of the 3 → 2 shift, for example, by depressing the accelerator, the input rotation speed falls below the engine rotation speed and the first one-way clutch F1 is engaged. , The first brake B1 is engaged. The engagement of the first brake B1 is applied to the first one-way clutch F1.
Is engaged, so that the hydraulic pressure is not particularly controlled,
This is performed by supplying line pressure based on switching of a shift valve or the like. However, when the vehicle speed increases on a downhill road or the like, the first one-way clutch F1 is not engaged, so hydraulic control is performed to prevent an engagement shock.
The first brake B1 is smoothly engaged.

It should be noted that the above embodiment is described with reference to FIGS.
Described the 3 → 2 shift in the transmission according to
The 4 → 2 shift can be similarly applied. Further, a two-axis transmission mechanism including a main transmission mechanism and an auxiliary transmission mechanism has been described, but a transmission mechanism having three or more axes can be similarly applied. Further, the present invention can be similarly applied to downshifting of another shift stage by another type of transmission.

Further, in the above-described embodiment, after the counter C1 reaches the fixed amount t1 from the time when the rotation acceleration ΔN of the input shaft rotation speed becomes 0 or more, 3 → by clutch-to-clutch (grab) is performed. Although the completion control of the brake B5 is started by determining that the second shift has been substantially started, the fixed amount t1 (counter C1
Count value), the rotational acceleration ΔN is more positive (+) than 0.
It is sufficient if the value is offset to the side and set so as not to cause a malfunction. Further, after the counter C2 has reached the fixed amount t2 from the point in time when the rotational acceleration ΔN of the input shaft rotational speed has become equal to or less than 0, it is determined that the 3 → 2 shift by clutch-to-clutch (grapping) has been completed. Although the completion control of the brake B5 has been completed, the fixed amount t2 (count amount of the counter C2) for determining the end of the shift is a value obtained by offsetting the rotational acceleration ΔN to the negative (−) side from 0, What is necessary is just to set so that malfunction may not occur. Note that the determination of the start and end of the shift is not limited to the input shaft rotation acceleration ΔN, and may be determined using other parameters.

In the above embodiment, the input shaft is in the free rotation state, and when the input shaft is in the engaged state, the normal shift start determination using the input shaft rotation speed change as an index and A shift end determination is made.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an electronic control unit according to the present invention.

FIG. 2 is a skeleton diagram showing a mechanism portion of an automatic transmission to which the present invention can be applied.

FIG. 3 is a view showing the operation of each friction engagement element.

FIG. 4 is a diagram schematically illustrating a hydraulic circuit related to a shift based on a clutch engagement-clutch change (clutch-to-clutch).

FIG. 5 is a flowchart showing control of a downshift release hydraulic pressure in clutch-to-clutch shift.

FIG. 6 is a flowchart showing control of an engagement-side hydraulic pressure of a downshift in clutch-to-clutch shift.

FIG. 7 is a flowchart showing control of a friction engagement element for engine braking by clutch-to-clutch shift.

FIG. 8 is a time chart showing a downshift according to the embodiment of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Automatic transmission 2 Main transmission mechanism 3 Input shaft 5 Sub transmission mechanism 6 Output shaft 13 Engine output shaft C1-C3, B1-B5 Friction engagement element B1 Friction engagement element (brake) for transmitting driving force B4 Release side Friction engagement element (brake) B5 Engagement-side friction engagement element (brake) 21 Control unit 21a Disengagement side control means 21b Engagement side control means 21c Shift progress control means 21e Drive force transmission control means 21f Input shaft rotation acceleration detection means 29,30,37 hydraulic servo SLS, SLU, frictional engaging element for the hydraulic P _C driving force transmission of the frictional engagement element hydraulic P _B engagement side frictional engagement element of the SLT hydraulic control means P _a release side Oil pressure ΔN Input shaft rotation acceleration Pw 'Standby engagement pressure

Continued on the front page (72) Inventor Seiwa Nomura 10 Takane, Fujii-machi, Anjo, Aichi Prefecture Inside Aisin AW Co., Ltd. (72) Kinzo Akita 10 Takane, Fujii-machi, Anjo, Aichi Prefecture Aisin F-term in AW Corporation (reference) 3J552 MA02 MA12 MA26 NA01 NB01 PA02 PA51 RA07 RB07 RC07 RC12 SA03 SA07 SA08 SA09 SB10 TA11 VA32Y VA33W VA62Z VA76Z VA78W VB01Z VC01Z VC03Z

Claims (10)

[Claims] An input shaft to which power from an engine output shaft is input, an output shaft connected to wheels, and a plurality of friction engagement elements for changing a power transmission path between the input shaft and the output shaft. A transmission mechanism having: a hydraulic servo that disconnects / engages the friction engagement element; a hydraulic control unit that controls the hydraulic pressure of the hydraulic servo; and a control unit that outputs a hydraulic control signal to the hydraulic control unit. A hydraulic control device for an automatic transmission, comprising: a release side control unit that controls a hydraulic pressure of a frictional element on a release side when downshifting to a predetermined gear position; and a downshift to the predetermined gear position. The engagement-side control means for controlling the hydraulic pressure of the engagement-side frictional engagement element, and the input shaft rotation acceleration detection means for detecting the input shaft rotation acceleration accompanying the downshift to the predetermined gear position. The control unit Wherein the determining the start or end of transmission in the downshift based on the detected input shaft rotational acceleration by the input shaft rotational acceleration detecting means, the hydraulic control system for an automatic transmission. 2. The control unit according to claim 1, wherein said input shaft rotation acceleration detected by said input shaft rotation acceleration detection means is substantially zero.
The hydraulic control device for an automatic transmission according to claim 1, wherein a start of a shift in the downshift is determined based on the above. 3. The control unit according to claim 2, wherein the input shaft rotation acceleration detected by the input shaft rotation acceleration detection means is substantially zero.
The hydraulic control device for an automatic transmission according to claim 1 or 2, wherein the end of the shift in the downshift is determined based on the following. 4. The engagement-side control means has a servo start control and a completion control, and ends the servo start control and starts the completion control based on judging the start of the shift, and The hydraulic control device for an automatic transmission according to any one of claims 1 to 3, wherein the completion control is ended based on determining that the shift has ended. 5. The apparatus according to claim 1, wherein said input shaft rotational acceleration detecting means detects substantially zero or more or substantially zero or less based on integrating a total sum of rotational change accelerations. The hydraulic control device for an automatic transmission according to any one of the above. 6. The input shaft rotation acceleration detection means starts counting based on the input shaft rotation acceleration being substantially equal to or greater than 0 or substantially equal to or less than 0, and when the count reaches a predetermined amount. The hydraulic control device for an automatic transmission according to any one of claims 1 to 4, wherein a start or an end of the shift in the downshift is determined based on the downshift. 7. A connection state between the input shaft and the output shaft is controlled by controlling a hydraulic pressure of a frictional engagement element for transmitting driving force, which is provided in parallel with the one-way clutch at the time of downshifting to the predetermined gear position. A driving force transmission control means for controlling a torque input from the engine at the time of the downshift; and a downshift to the predetermined gear position, the driving force being transmitted until a shift associated with the downshift is started. Maintaining the connection state between the input shaft and the output shaft by the transmission control means,
7. The hydraulic control device for an automatic transmission according to claim 1, further comprising: a shift progress control unit that controls the connection state to be disconnected. 8. A stroke learning control when the hydraulic servo of the engagement side frictional engagement element is loosened while the connection state between the input shaft and the output shaft is maintained by the driving force transmission control means. 8. The hydraulic control apparatus for an automatic transmission according to claim 7, further comprising learning control means for performing a learning operation based on a rotation state of said input shaft. 9. The hydraulic control device for an automatic transmission according to claim 1, wherein the transmission mechanism includes a main transmission mechanism and an auxiliary transmission mechanism. 10. The downshift to the predetermined gear position, the downshift to the predetermined gear position, the driving force transmission control unit controls the driving force transmission friction until the shift associated with the downshift is started. The hydraulic control device for an automatic transmission according to claim 7, wherein the drive of the engagement element is controlled by a standby engagement pressure that can maintain the engagement to such an extent that slippage does not occur.