JP2000145940A - Hydraulic controller for automatic transmission - Google Patents

Abstract

PROBLEM TO BE SOLVED: To perform transmission by proper grip changing, wherein no tie-up occurs even if it is not possible to perform feedback control for a releasing side oil pressure with the change of an input shaft rotational speed set as a target value while a transmission mechanism to be downshifted is in a free rotational state. SOLUTION: Before transmission by grip changing (releasing of one brake and engaging of the other brake) in a sub-transmission mechanism, if a brake provided side by side with the one-way clutch of a main transmission mechanism is released to be in a free rotational state and downshifting by the grip changing is executed, a gear ratio rotational difference ΔN between a rotational speed obtained by multiplying an output rotational speed by a gear ratio before transmission and an actual input shaft rotational speed is compared with a specified threshold value NIim, and the progressing state of the transmission is judged. If the progress of the transmission is not satisfactory, then feedback control is performed to reduce a releasing side oil pressure PA by a specified amount PFB. The feedback control is repeated for each cycle until the gear ratio rotational difference ΔN becomes smaller than the threshold value NIim.

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 low speed, the friction engagement element for the downshift is changed,
The difference between the engine speed and the input shaft speed is large, causing a torque rise in a short time, giving an uncomfortable feeling such as being pushed forward of the vehicle.

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. Therefore, the feedback control of the release hydraulic pressure cannot be performed so that the change in the input shaft rotation speed becomes the target value as in a normal shift.

Therefore, in the downshift according to the conventional technique, the disengagement hydraulic pressure command value waits at a predetermined standby pressure while the friction engagement element provided side by side with the one-way clutch is released, and the engagement hydraulic pressure command is issued. After the loosening command is issued, the engagement-side hydraulic pressure is gradually increased at a constant increase rate, and the shift is proceeding.

For this reason, when the disengagement-side frictional engagement element is not released due to a variation in friction coefficient of the frictional engagement element or a response delay of the hydraulic pressure, the engagement-side frictional engagement command is issued based on the engagement-side hydraulic pressure command. The mating elements may engage to create tie-ups. In this state, since the speed change does not proceed, the input shaft speed does not change, and the input shaft speed is maintained at the high-speed speed. Thereafter, the input shaft speed rapidly decreases due to the release of the release-side friction engagement element. As a result, the output torque suddenly changes due to a sudden change in the inertia torque in the transmission, which causes a shift shock.

Therefore, the present invention makes it possible to perform a shift by appropriate gripping without causing tie-up or the like even when the downshifting transmission mechanism is in a free rotation state.
An object of the present invention is to provide a hydraulic control device for an automatic transmission that solves the above-mentioned problems.

[0010]

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 transmission mechanism having a plurality of friction engagement elements (C1 to C3, B1 to B5) for changing a power transmission path between the input shaft and the output shaft; and a hydraulic servo for disconnecting and engaging the friction engagement elements. (29, 30), an automatic transmission including hydraulic control means (SLS, SLU) for controlling the hydraulic pressure of these hydraulic servos, and a control unit (21) for outputting a hydraulic control signal to the hydraulic control means. In the hydraulic control device, the control unit may be configured to release the frictional engagement element (e.g., the fourth brake B
4) Disengagement side control means (21a) for controlling the hydraulic pressure for use, and the engagement side for controlling the hydraulic pressure for the friction engagement element (for example, the fifth brake B5) which becomes the engagement side when downshifting to the predetermined gear position. The control means (21b) detects the progress of the downshift based on a rotation change based on a gear ratio changed at the time of the downshift to the predetermined gear, and compares the detected value (ΔN) with a predetermined threshold (Nlim). And a shift progress determining means (21c, S5,
S10), and while the shift determining means determines that the progress of the shift is insufficient, the release-side control means supplies a predetermined amount (P
Feedback control means (21d, S6, S11) for instructing the automatic transmission to reduce the _FB ) sequentially.

According to a second aspect of the present invention, the speed change mechanism comprises a first speed change mechanism (2) comprising a first gear unit (15) and a second speed change mechanism comprising a second gear unit (11).
Wherein the first transmission mechanism is in a free-rotation state, and the second transmission mechanism comprises the release-side friction engagement element (B4) and the engagement-side friction engagement element. 2. The hydraulic control device for an automatic transmission according to claim 1, wherein the downshift to the predetermined shift speed (second speed) is performed by grasping (B5).

According to a third aspect of the present invention, the first transmission mechanism (2) has a one-way clutch (F1) and a brake (B1) arranged in parallel with the one-way clutch (F1). The hydraulic control device for an automatic transmission according to claim 2, wherein the brake (B1) is released prior to the downshift to the predetermined shift speed (second speed) according to (5).

According to a fourth aspect of the present invention, the disengagement-side control means (21a) includes a stand-by control (A) in which the disengagement-side friction engagement element (B4) maintains a torque capacity corresponding to an input torque (T _T ). S1 to S6) and the predetermined gradient (δP
4. The hydraulic control apparatus for an automatic transmission according to claim 1, further comprising: completion control (S8 to S12) for lowering the hydraulic pressure in _F ) (see FIGS. 5, 7, and 8). It is in.

According to a fifth aspect of the present invention, the pressure reduction command (S6) by the predetermined amount (P _FB ) by the feedback control means (21d) is performed for a standby pressure (Pw) in the standby control. (See FIGS. 5 and 8). The hydraulic control device for an automatic transmission according to claim 4.

According to a sixth aspect of the present invention, in the pressure reducing command (S11) of the predetermined amount (P _FB ) by the feedback control means (21d), the hydraulic pressure (δP _E ) in the completion control of the release side control means. (See FIGS. 5 and 8), the hydraulic control device for an automatic transmission according to claim 4 or 5.

According to a seventh aspect of the present invention, the speed change progress judging means (21c) is configured to calculate a speed (N _i ) obtained by multiplying the output shaft speed (N _O ) by a gear ratio (gi) before a speed change. The gear ratio rotation difference (Δ), which is the difference from the actual input shaft rotation speed (N _T )
2. The progress of shifting is determined by comparing N) with a predetermined threshold value (Nlim) near a rotating speed (N _i ) obtained by multiplying the output shaft speed by a gear ratio before shifting. Or 6
The hydraulic control device for an automatic transmission according to any one of the above.

[Operation] Based on the above-described configuration, for example, a change of gripping (fourth brake B
Prior to the shift by the release of the fourth brake 4 and the engagement of the fifth brake B5), the brake (B1) arranged in parallel with the one-way clutch (F1) of the first transmission mechanism (2) is released to be in a free rotation state. When performing a downshift by gripping, a rotation change based on the gear ratio changed at the time of the downshift, for example, a rotation speed (N _i ) obtained by multiplying the output rotation speed (N _O ) by the gear ratio (g) before shifting. And a gear ratio rotation difference (ΔN) between the rotation speed and the actual input shaft rotation speed (N _T ). When the detection value (ΔN) is larger than a predetermined threshold (Nlim),
When it is determined that the shift is not proceeding sufficiently, feedback control for reducing the release hydraulic pressure (PA) by a predetermined amount (P _FB ) is performed. The feedback control is repeatedly performed for each cycle until it is determined that the shift has progressed, for example, when the detection value (ΔN) becomes smaller than the threshold value (Nlim).

The reference numerals in the parentheses are for comparison with the drawings, but do not limit the configuration of the present invention.

[0019]

According to the first aspect of the present invention, the progress of the downshift is detected based on the rotation change based on the gear ratio, so that the progress of the shift can be determined without relying on the input shaft speed. Since the release-side hydraulic pressure is reduced by a predetermined amount based on the determination, a tie-up or the like can be prevented, and a smooth downshift can be executed.

According to the second aspect of the present invention, since the first speed change mechanism is in a free rotation state and the second speed change mechanism performs a downshift by gripping, the occurrence of a shift shock due to the gripping is generated. And in this case,
Although feedback control based on the input shaft rotation speed cannot be performed, smooth downshifting can be performed by feedback control based on rotation change accompanying the gear ratio change and reduction in pressure by a predetermined amount based on shift progress determination based on a threshold value.

According to the third aspect of the present invention, the downshift can be automatically and smoothly performed to the predetermined gear by interposing the one-way clutch.

According to the fourth aspect of the present invention, the release-side hydraulic pressure stands by at a pressure that maintains a torque capacity corresponding to the input torque, so that the occurrence of engine blowing can be prevented, while the release by the feedback control is prevented. Tie-up can be prevented by lowering the side hydraulic pressure, and a smooth downshift can be performed.

According to the fifth aspect of the present invention, the standby pressure in the standby control is reduced by a predetermined amount by the feedback control, so that the feedback control is started from a relatively early stage of the shift to promote the progress of the shift. Tie-up can be prevented.

According to the present invention, since the pressure reduction by the predetermined gradient in the completion control is further reduced by the predetermined amount by the feedback control, it is possible to reliably prevent the delay in the progress of the shift.

According to the seventh aspect of the present invention, the difference between the rotation speed based on the output shaft rotation speed and the gear ratio before shifting and the actual rotation speed of the input shaft is determined by the threshold based on the output shaft rotation speed. Since the comparison is made, it is possible to reliably detect the shift progress from the state before the shift, and to reliably prevent the occurrence of tie-up.

[0026]

Embodiments of the present invention will be described below with reference to the drawings.

The five-speed automatic transmission 1 is, as shown in FIG.
A torque converter 4, a three-speed main transmission mechanism 2, a three-speed auxiliary transmission mechanism 5, and a differential 8 are provided, and these parts are housed in a case integrally connected to each other. The torque converter 4 includes a lock-up clutch 4a. The input shaft 3 of the main speed change mechanism 2 is transmitted from the engine crankshaft 13 through an oil flow in the torque converter or through a mechanical connection by the lock-up clutch. To enter. Then, 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 ( Left and right axles 14a, 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 includes a sun gear S2, a ring gear R2, and a pinion P meshing with the sun gear S2.
2 and a common carrier CR that supports the pinion P3 meshing with the ring gear R2 together with the pinion P1 of the simple planetary gear 7.

The input shaft 3 interlocked with 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 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 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 automatic transmission 1 can obtain the second speed as a whole. Note that, at this time, the first brake B1 is also operated, but when the second speed is established due to the coast down, the first brake B1 is released. The first brake B1
Switches from disengagement to engagement in a state where the above-described second speed is achieved.

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 held 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, so that the automatic transmission 1 as a whole is driven at the second speed of the main transmission mechanism 2 and the second speed of the auxiliary transmission mechanism 5. 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 low speed state of the third speed, 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.

In the low speed state of the fourth speed, 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. 2, the dotted circles indicate the operating state (4, 3 or 2 ranges) of the engine brake during coasting. 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 the accelerator pedal depression amount of the driver. Degree sensor 23, sensor 2 for detecting the input shaft rotation speed (= turbine rotation speed) of the transmission (automatic transmission mechanism)
5. Each signal from the vehicle speed (= automatic transmission output shaft rotation speed) sensor 26 and the oil temperature sensor 27 is input and output to the linear solenoid valves SLS and SLU of the hydraulic circuit. The control section 21 is configured to shift to a predetermined speed (second speed) via a one-way clutch (F1) with a release control means 21a for controlling the release hydraulic pressure, an engagement control means 21b for controlling the engagement hydraulic pressure. The downshift progress is detected by a rotation change based on the gear ratio changed at the time of the downshift, and the detected value (ΔN) and a predetermined threshold (Nlin) are detected.
And a shift progress determining means 21c for determining the progress of the shift by comparing the shift progress determining means with the release side control means 21a while the shift progress determining means determines that the shift progress is insufficient.
And a feedback control means 21d for instructing the predetermined amount (P _FB ) to be sequentially reduced.

FIG. 4 is a diagram schematically showing a hydraulic circuit.
A plurality of friction engagement elements (clutches and clutches) having the two linear solenoid valves SLS and SLU and switching the transmission path of the planetary gear unit of the automatic transmission mechanism to achieve, for example, the fifth forward speed and the first reverse speed. And a plurality of hydraulic servos 29 and 30 for connecting and disconnecting brakes. Also, the linear solenoid to the input port a _1, a ₂ valves SLS and SLU is supplied with the solenoid modulator pressure, the control pressure each pressure control valve 31 from output port b _1, b ₂ of the linear solenoid valve , 32 control oil chambers 3
1a and 32a. The line pressure is supplied to the input ports 31b and 32b of the pressure control valves 31 and 32, respectively. The pressure adjusted hydraulic pressure from the output ports 31c and 32c adjusted by the control oil pressure is applied to the pressure control valves 31 and 32, respectively.
The hydraulic servos 29 and 30 are supplied to the hydraulic servos 29 and 30 via shift valves 33 and 35, respectively.

The present hydraulic circuit shows a basic concept of so-called clutch-to-clutch shifting in which one friction engagement element is released and the other friction engagement element is engaged. 29 and 30 and the shift valves 33 and 35 are symbolically shown. Actually, many hydraulic servos are provided corresponding to the automatic transmission mechanism. The hydraulic servo for the fourth brake B4, the hydraulic servo for the fifth brake B5, the hydraulic servo for the third clutch C3 and the hydraulic servo for the fourth brake B4 during the 4 → 3 shift. There are also many shift valves that switch the hydraulic pressure to

In the 3 → 2 downshift, the hydraulic pressure of the hydraulic brake 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 by a predetermined shift valve or the like, and after the gripping control is completed, the hydraulic pressure is supplied after the first one-way clutch F1 is engaged. Is done. Therefore, the fourth transmission in the subtransmission mechanism 5
The downshift due to gripping of the fifth brakes B4 and B5 is 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. Thereafter, when the rotation of the sun gear S2 switches from normal rotation to reverse rotation due to depression of the accelerator or further reduction of the vehicle speed, that is, at the time when the rotation speed based on the gear ratio from the output shaft side falls below the engine rotation speed. , The first one-way clutch F1
Are engaged, the free rotation state is released and the second speed stage is established, and then the first brake B1 is engaged.

Next, a downshift by clutch-to-clutch, for example, 3 → 2 shift will be described with reference to FIGS. In this downshift, the vehicle is downshifted (coasted down) as the vehicle speed decreases with the accelerator pedal released, that is, the rotation speed (turbine rotation speed) _{NT of the} input shaft 3 is greater than the engine idle rotation speed. Although the description has been made on the basis of the downshift in the high power-off region, the present invention is not limited to this, and can be similarly applied to the downshift in the power-on region in which the input shaft speed is lower than the engine idle speed. Also, in the 3 → 2 shift, specifically, the release side hydraulic pressure PA is set to the fourth brake B4.
The engagement side oil pressure PB is the oil pressure for the fifth brake B5, and the shift by the clutch-to-clutch (grab change) is performed by the first brake B5 as described above.
This is performed in a free rotation state (neutral state) of the subtransmission mechanism 5 in which the first and first one-way clutches are released.

First, the control of the release hydraulic pressure PA will be described with reference to FIG. 5. Based on signals from the throttle opening sensor 23 and the vehicle speed sensor 26, the control unit 21 uses a map to perform 3 → 2 shift and the like. When judging a downshift,
After a predetermined delay time from the shift determination, time measurement is started and shift control is started (S1). At the start time point (t = 0), the hydraulic pressure for the first brake B1 is in a released state due to communication with the drain by a shift valve or the like, and the brake B1 is in a released state. The one-way clutch F1 is also in the non-engaged state, the main transmission mechanism 2 is in the free rotation state (neutral state), and the release-side hydraulic pressure PA, for example, the hydraulic pressure for the fourth brake B4 is the engagement pressure. And the release-side friction engagement element (for example, the fourth
Brake B4) is engaged. Then, the release torque T _A is calculated by a function of the input torque T _t (S2). The input torque _Tt is obtained by calculating the engine torque based on the throttle opening and the engine speed using a map, further calculating the speed ratio from the input / output speed of the torque converter, obtaining the torque ratio from the speed ratio on the map, It is determined by multiplying the engine torque by the above torque ratio. Furthermore,
The release torque T _A is determined by the torque sharing ratio and the like participating in the input torque.

The waiting engagement pressure Pw release side from the release side torque T _A is calculated (S3), and outputs a control signal to the linear solenoid valve to be該待machine engagement pressure Pw (S
4). Then, in this state, the timing is equal to the predetermined dead zone time t.
_It is determined whether _FB has elapsed and whether the actual gear ratio rotation difference ΔN has exceeded a predetermined threshold value Nlim (for example, −50 [rpm]) (S5). Here, the actual gear ratio rotation difference ΔN
Is the difference between the rotation speed of the input shaft based on the gear ratio before gear shifting based on the output shaft rotation speed and the actual input shaft rotation speed at that time, and is the output shaft rotation speed obtained from the vehicle speed sensor 26. the N _O, the pre-shift gear ratio g _i, the input shaft rotational speed sensor 2
Actual input shaft rotational speed obtained from 5 (turbine speed) When N _T, is determined by _{ΔN = N O × g i -N} T. Note that the above N _O × g _i is the input shaft speed N based on the pre-shift gear ratio g _i from the output shaft speed N _O.
i .

In step S5, the time is in a state where the predetermined dead zone time t _FB has elapsed (t> t _FB ), and the gear ratio rotation difference ΔN is equal to or greater than the predetermined threshold Nlim (ΔN> N).
lim) (eg, ΔN = 0) (step S5)
YES), it is determined that the shift progress is not sufficient in the state of the gear ratio (for example, third speed) before the shift, and the feedback control of step S6 is performed (S6). The feedback control, the release-side standby oil Pw based on the release-side torque T _A obtained in the step S3, S4, are controlled so as to reduce the feedback pressure P _FB having a predetermined constant pressure (PA = f _PA (T _A) -P _FB).

The standby control is performed in steps S2 to S6. The standby control time tw is set to be shorter than the engagement-side servo activation time t _SE described later. And
The standby control including the feedback control is repeated until the standby control time tw elapses (S7). In this state, until the gear ratio rotation difference ΔN becomes smaller than the threshold value Nlim (ΔN <Nlim) ( S5; NO),
For each cycle, the fixed value P _FB based on the step S6
The feedback control based on the pressure reduction control is performed repeatedly. The standby control time tw is set to be shorter than the engagement-side servo activation control time t _SE (see step S36). This is because the engagement-side hydraulic pressure fills the hydraulic chamber of the hydraulic servo. After _SA , the increase in the engine speed is suppressed by increasing the hydraulic pressure on the engagement side by increasing the oil pressure on the engagement side at the predetermined low pressure P _S2 (see step S34) of the servo activation control. This is because it is not necessary to continue the release-side standby control until the engagement-side servo activation control ends. As a result, tie-up with the engagement-side frictional engagement element can be prevented.

When the standby control is completed (t> tw),
Immediately enters the completion control, and sets the preset completion time t
_A timer is set for _FIN (t = t _FIN ) (S8). Further, the release-side hydraulic pressure PA is swept down by a hydraulic pressure δP _E having a predetermined gradient (S
9).

Then, in the same manner as described above, the actual gear ratio rotation difference ΔN is compared with the predetermined threshold value Nlim, and the progress of the shift is determined again (S10). If the gear ratio rotation difference ΔN is larger than the threshold value Nlim (YES), feedback control is performed in which the feedback pressure P _FB having the constant value is reduced from the hydraulic pressure δP _{E having} a predetermined gradient in step S9 (S11). The completion control is repeated until the preset completion time t _FIN elapses (t ≦ 0) (S12). At this time, the feedback control including the pressure reduction of the constant value P _FB is performed until the gear ratio rotation difference ΔN becomes smaller than the predetermined threshold value Nlim (step S10 is determined to be N).
O), and is repeated every cycle.

Next, according to the flowchart of FIG.
Control of the engagement side hydraulic pressure in the downshift will be described.

First, time measurement is started based on a downshift command from the control unit 21 (S30), and the engagement side hydraulic pressure PB,
For example, a predetermined signal is output to the linear solenoid valve SLS (or SLU) so that the hydraulic pressure to the fifth brake B5 hydraulic servo becomes the predetermined pressure P _S1 (S31). The predetermined pressure P _S1 is set to a hydraulic pressure required to fill the hydraulic chamber of the hydraulic servo, and is maintained for a predetermined time t _SA . When said predetermined constant-time t _SA has passed (S32), the engagement side pressure PB is swept down at a predetermined gradient _{[(P S1 -P S2) /} t SB] (S33), the engagement side pressure PB is predetermined low pressure P _{When S2} is reached (S34), the sweep-down is stopped and the predetermined low pressure P _S2 is maintained (S35). The predetermined low pressure P _S2 is and a on the piston stroke pressure or is set to pressure which does not cause torque capacity in the engagement side frictional engagement element (e.g., the fifth brake B5), the predetermined low pressure P _S2 is clocked t Is held until a predetermined time t _SE elapses (S36). Servo start control is performed in steps S31 to S36.

When the servo activation control is completed (t ≧ t
_SE ), immediately enter the completion control. In the completion control, the same time t _FIN as the completion control time set in advance in the release hydraulic pressure control is set in the timer (S37). The engagement hydraulic pressure PB is swept up by the hydraulic [delta] P _F of a predetermined slope which is set in advance (S38),
Until the predetermined time t _FIN set above elapses (t ≦
0), the sweep-up is continued (S39), and when the time elapses, the completion control ends, and the 3 → 2 shift is completed.

The first brake B1 is released before the start of timing in steps S1 and S30 of the 3 → 2 shift by the clutch-to-clutch (change of clutch), and the step S
12. After the completion of the completion control in S39, that is, after the completion of the 3 → 2 shift, the input rotational speed falls below the engine rotational speed due to, for example, depression of the accelerator or further reduction in vehicle speed, and the first one-way clutch F1 is engaged. After being combined,
The first brake B1 is engaged. Since the first one-way clutch F1 is engaged, the engagement of the first brake B1 is performed by supply of line pressure based on switching of a shift valve or the like without particularly controlling hydraulic pressure.

Next, with reference to the time charts of FIGS. 7 and 8, first, based on FIG. 7, for comparison with the embodiment of the present invention, feedback control of the release hydraulic pressure shown in FIG. A case in which S6, S10, and S11 are not performed will be described. Release side oil pressure command value PA
Becomes a predetermined standby hydraulic pressure Pw, the release-side actual hydraulic pressure (indicated by a dotted line) decreases with a delay, and at the same time, the command value PB of the engagement-side hydraulic pressure is controlled by the servo activation, so that the engagement-side actual hydraulic pressure ( A dashed line indicates a friction engagement element (for example, a fifth brake B).
Perform the loosening operation of 5). Next, based on the sweep-down δP _E of the release-side hydraulic pressure command value, the release-side actual hydraulic pressure gradually decreases to gradually reduce the torque capacity of the release-side friction engagement element (for example, the fourth brake B4), and at the same time, The engagement-side hydraulic pressure command value PB increases at a predetermined gradient δ _F , and the actual engagement-side actual oil pressure also gradually increases, thereby increasing the torque of the engagement-side frictional engagement element (for example, the fifth brake B5). Increase capacity gradually.

As a result, there is no feedback control,
A downshift (3 → 2 shift) by clutch-to-clutch (change of clutch) is performed. At this time, as described above, the first brake B1 is released and the first one-way clutch F1 idles. Main transmission mechanism 2
Is in a free rotation state (neutral state), and thus the 3 → 2 shift by re-grip of the subtransmission mechanism 5 is performed in a state where the continuous traction with the input shaft 3 is cut off. For this reason,
The change in the rotation of the input shaft rotation speed _NT is small, and the feedback control of the release hydraulic pressure PA with the input shaft rotation speed set to a predetermined target value cannot be performed.

For this reason, it may take a long time to reduce the torque capacity of the disengagement-side friction engagement element (the fourth brake B4) due to variations in the output pressure, friction coefficient of the friction material, response delay of the hydraulic pressure, and the like. In this state, when the engagement side frictional engagement element (fifth brake B5) is, increases gradually torque capacity based on the hydraulic pressure command value with a predetermined slope P _F of the engagement hydraulic pressure PA, tie-up state Becomes

[0062] In this state, it remains gear ratio g _i of the actual gear ratio is pre-shift (third speed), the gear ratio rotational difference Δ
N continues to be 0, and the gear ratio (g) (g) after the shift (second speed) is based on the shift progress due to the delayed gripping of both brakes.
Toward _i-1 ), the actual gear ratio rotation difference ΔN rapidly changes in the negative direction. Also, the input shaft rotation speed _NT does not initially change to the low speed side, and then rapidly changes to the high speed side with the progress of the shift by the actual gear ratio, and the 3 → 2 shift ends. Then, when the accelerator pedal is depressed or the vehicle speed further decreases, the rotation speed of the input shaft (actually, the change in the rotation direction of the sun gear S2) decreases along with the actual speed change toward the second speed. The one-way clutch F1 is locked, and the transmission 1 is in the low speed (second speed). Thereafter, the first brake B1 is switched to the engaged state.

Therefore, in the hydraulic control without the feedback control, a shift shock may be generated due to a sudden change of the inertia torque inside the transmission even when the downshift due to gripping is in a free rotation state.

FIG. 8 is intended to solve the problem shown in FIG. 7 and shows a time chart of the hydraulic control shown in FIGS. Here, the engagement-side oil pressure command value PB is similar to that shown in FIG. 7, after the servo starting control, sweep up by a hydraulic [delta] P _F of a predetermined gradient.

The release side oil pressure command value PA is held at the standby pressure Pw for a predetermined time and waits for the actual oil pressure (dashed line) to drop. Then, after a lapse of a predetermined time t _FB , the actual gear ratio rotation difference ΔN is compared with a predetermined threshold Nlim, and ΔN> N
In the case of lim, that is, when the actual gear ratio is before the shift (third speed) and the shift is not proceeding sufficiently, the constant value P _FB is reduced for each cycle as shown by the broken line (see S6). ). The feedback control by the constant pressure reduction in each cycle is continued until the gear ratio rotation difference ΔN becomes smaller than the threshold value Nlim (changes in the negative direction) during the standby control.

As a result, the actual hydraulic pressure on the release side (indicated by the bold dashed line) also decreases. Even if the standby control is completed and the completion control is entered, the actual gear ratio rotation difference ΔN is not less than the predetermined threshold Nlim.
With the above, it is determined that the shift is not sufficiently advanced, and the feedback control for subtracting the constant value P _FB from the oil pressure δP _{E having the} predetermined gradient is continuously performed (see S11). The feedback control is performed for each cycle of the completion control, and accordingly, the release-side actual hydraulic pressure decreases relatively rapidly. Thus, together rise coupled with by predetermined gradient [delta] P _F of the engagement side hydraulic PA, without causing tie-up, a downshift by engagement switching (3 → 2 shift) is performed in a timely manner.

[0067] With the progress of the speed change, the actual gear ratio rotational difference ΔN is smaller than a predetermined threshold value Nlim (G point), the feedback control is stopped, until the sweep-down by a predetermined gradient [delta] P _F becomes the release state You can continue.

In the above embodiment, the 3 → 2 shift in the transmissions shown in FIGS. 2 and 3 has been described.
→ Two shifts can be applied similarly. Further, the present invention can be similarly applied to downshifting of another shift speed by another type of transmission. Further, prior to the gear change by the grip change, the frictional engagement element (specifically, the first brake B1) on the transmission upstream side of the frictional engagement element related to the gear change is released, and after the one-way clutch is engaged, the frictional engagement element is disengaged. Although the engagement element is engaged, the friction engagement element may be kept in the released state, and may be brought into the free rotation state only by the one-way clutch arranged in parallel therewith. As in the case of a 4 → 1 shift, the second one-way clutch F is held with the third brake B3 released.
2 can be similarly applied to a downshift. Further, the present invention can be applied to a normal downshift without the one-way clutch and without the gear involved in gripping being in a free rotation state.

The change situation of the shift based on the gear ratio is as follows.
As described above, the index is not limited to the difference ΔN between the input shaft rotation speed based on the gear ratio from the output shaft and the actual rotation speed, and may be any index related to rotation change based on the gear ratio.
Further, as shown in the above prior art, as disclosed in Japanese Patent Application Laid-Open No. 9-21462, when the main transmission mechanism on the input shaft side is grasped and the speed is changed, the auxiliary transmission mechanism on the output side is provided in parallel with the one-way clutch. In the case where the brake is released to be in the free rotation state, the progress of the shift may be detected based on the rotation speed based on the gear ratio from the input shaft.

[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 time chart showing a downshift by clutch-to-clutch shift when there is no feedback control.

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 First (main) transmission mechanism 3 Input shaft 5 Second (sub) transmission mechanism 6 Output shaft 11 Second gear train 13 Engine output shaft 15 First gear train C1-C3, B1- B5 Friction engagement element B4 Release friction engagement element (fourth brake) B5 Release friction engagement element (fourth brake) B1 (first) brake F1 (first) one-way clutch 21 (electronic) control unit 21a Release control means 21b Engagement side control means 21c Shift progress determination means 21d Feedback control means 29, 30 Hydraulic servo SLS, SLU Hydraulic control means PA Release side hydraulic pressure PB Engagement hydraulic pressure Pw Standby pressure _PFB Predetermined amount (feedback pressure) N _O Output shaft rotation speed N _T Input shaft rotation speed N _i Input shaft rotation speed depending on gear ratio g _i Gear ratio before speed change ΔN Gear ratio rotation difference Nlim threshold

 ──────────────────────────────────────────────────の Continuing on the front page (72) Inventor Koichi Kojima 10 Takane, Fujii-machi, Anjo, Aichi Prefecture Inside Aisin AW Co., Ltd. (72) Inventor Seiwa Nomura 10 Takane, Fujii-cho, Anjo, Aichi Prefecture Aishi Inside AW Co., Ltd. (72) Inventor Masaaki Nishida 10th Takane, Fujii-cho, Anjo-city, Aichi Prefecture Inside Ain-Wash Co., Ltd. (72) Yoshihisa Yamamoto 10th Takane, Fujiicho, Anjo-city, Aichi Prefecture Aishi Inside AW Co., Ltd.

Claims (7)

[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 for a friction engagement element that is released when a downshift to a predetermined gear is performed; Engagement-side control means for controlling a hydraulic pressure for a frictional engagement element to be engaged when downshifting; and a progress state of the downshift by a rotation change based on a gear ratio changed when downshifting to the predetermined gear position. And a shift progress judging means for judging the progress of the shift by comparing the detected value with a predetermined threshold value. Feedback control means for instructing the side control means to sequentially reduce the predetermined amount. A hydraulic control apparatus for an automatic transmission, comprising: 2. The transmission mechanism includes a first transmission mechanism including a first gear unit, and a second transmission mechanism including a second gear unit, wherein the first transmission mechanism is in a free rotation state. And the second
2. The hydraulic control device for an automatic transmission according to claim 1, wherein the transmission mechanism shifts down to the predetermined shift speed by grasping the disengagement-side friction engagement element and the engagement-side friction engagement element. 3. 3. The first transmission mechanism has a one-way clutch and a brake provided in parallel with the one-way clutch, and releases the brake prior to downshifting to the predetermined gear by the second transmission mechanism. The hydraulic control device for an automatic transmission according to claim 2, comprising: 4. The release-side control means includes: a standby control in which the release-side frictional engagement element maintains a torque capacity corresponding to an input torque; and a completion control in which the hydraulic pressure is reduced at a predetermined gradient from the standby control. The hydraulic control device for an automatic transmission according to any one of claims 1 to 3, comprising: 5. The hydraulic pressure control apparatus for an automatic transmission according to claim 4, wherein the pressure reduction command by the predetermined amount by the feedback control means is performed for a standby pressure in the standby control. 6. The hydraulic pressure control device for an automatic transmission according to claim 4, wherein the pressure reduction command by the predetermined amount by the feedback control means is performed with respect to a hydraulic pressure in the completion control of the release-side control means. 7. A gear ratio rotation difference comprising a difference between a rotation speed obtained by multiplying the output shaft rotation speed by a gear ratio before a shift and an actual input shaft rotation speed; The hydraulic control device for an automatic transmission according to any one of claims 1 to 6, wherein the progress of the shift is determined by comparing the number with a predetermined threshold value near a rotational speed obtained by multiplying the number by a gear ratio before the shift.