JP3296889B2 - Control device for automatic transmission - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control device for an automatic transmission having a hydraulic frictional fastening element.

[0002]

2. Description of the Related Art Generally, a torque converter and a transmission gear mechanism are arranged in series in an automatic transmission for an automobile, and the torque converter changes the torque of an engine output shaft and transmits the torque to a turbine shaft to transmit the torque to a turbine shaft. Are adapted to further shift the torque of the turbine shaft and transmit the torque to the drive wheels. Here, the transmission gear mechanism is generally a planetary gear mechanism having a plurality of gears such as a sun gear, a ring gear, and a pinion gear, and the transmission gear mechanism includes a clutch that turns on and off transmission of torque to a predetermined gear, Alternatively, various hydraulic friction engagement elements such as a brake for fixing (brake-on) and releasing (brake-off) a predetermined gear are provided. A hydraulic mechanism for supplying and discharging hydraulic pressure (hydraulic oil) to and from each of these frictional engagement elements is provided, and the on / off pattern of each of the frictional engagement elements is switched by this hydraulic mechanism so that gear shifting is performed. Has become.

In such an automatic transmission, the line pressure or the operating oil pressure of the hydraulic mechanism must be an appropriate pressure corresponding to the power transmission amount at each frictional engagement element, and if the line pressure is higher than necessary, This causes an increase in power loss and a shift shock during shifting. Conversely, if the line pressure is too low, the frictional fastening elements will slip, causing abnormal wear or abnormal heat generation on the friction plates. For this reason, in a conventional automatic transmission, the line pressure is usually
The control unit is controlled in accordance with the throttle opening (engine load) or in accordance with the throttle opening and the turbine speed.

[0004]

However, in such a conventional automatic transmission, at the time of racing selection, that is, when performing an operation such as increasing the engine speed in the N range and shifting to the D range in order to start suddenly, Since the throttle opening is not so large, the rotational speed difference between the driving-side friction plate and the driven-side friction plate of the friction fastening element that is fastened at the start is large despite the line pressure is relatively low. Therefore, the time required to fasten the friction fastening element increases, and therefore, the time during which slippage occurs between the driving friction plate and the driven friction plate increases, and seizure occurs in the friction fastening element, Alternatively, there arises a problem that the temperature of the friction fastening element becomes high. Specifically, when starting in the D range, normally, the forward clutch is engaged and the transmission gear mechanism is set to the first speed, so that the forward clutch seizes or becomes hot.

By the way, in an automobile equipped with such an automatic transmission, when the transmission gear mechanism is set to the first speed at the time of starting in the D range, the gear ratio (torque ratio) is set at the first speed.
Is so large that a strong shock occurs when starting,
There is a problem that the drive wheels slip. Therefore,
There has been proposed an automatic transmission in which the transmission gear mechanism is temporarily set to a third speed having a small gear ratio (torque ratio) at the time of starting to prevent the occurrence of such a shock or slip (for example, Japanese Patent Publication No. -69018).

However, when the transmission gear mechanism is first set to the third speed when starting in the D range, the forward clutch, the coast clutch, and the 3-4 clutch are engaged when shifting to the third speed. . Therefore, when the above-mentioned racing select is performed,
Since abnormal wear or high temperature occurs in these three clutches, there is a problem that the above-mentioned problems become particularly significant.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned conventional problems, and it is possible to quickly fasten a friction fastening element even when a racing select is performed, and seizure occurs in the friction fastening element. It is an object of the present invention to provide a control device for an automatic transmission, which can prevent the occurrence of the above.

[0008]

In order to achieve the above object, as shown in FIG. 1, the first invention comprises a plurality of friction fastening elements A and a hydraulic mechanism for operating the friction fastening elements A. In the control device D of the automatic transmission C provided with B, the operating pressure of the hydraulic mechanism B is controlled so as to correspond to at least the engine speed in the neutral range, and to increase the line pressure as the engine speed increases. ,And,
When the automatic transmission C is shifted from the neutral range to the drive range, hydraulic control means E is provided, which keeps the operating oil pressure in the neutral range immediately before the shift for a predetermined time after the shift. A control device for a transmission is provided.

[0009] A second aspect of the present invention provides a plurality of frictional fastening elements A,
In the control device of the automatic transmission C provided with the hydraulic mechanism B for operating the frictional engagement element A, at least the engine speed in the neutral range is adjusted so that the line pressure increases as the engine speed increases. When the operating oil pressure of the hydraulic mechanism B is controlled and the automatic transmission C is shifted from the neutral range to the drive range,
There is provided a control device for an automatic transmission, comprising a hydraulic control means E for controlling an operating oil pressure of a hydraulic mechanism B in correspondence with an engine speed for a predetermined time after the shift.

[0010]

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be specifically described below.
As shown in FIG. 2, the automatic transmission AT is provided with a torque converter 2 that changes the torque of the engine output shaft 1 via hydraulic oil. The torque converter 2 includes a pump that rotates integrally with the engine output shaft 1. 3, a turbine 4 that rotates integrally with the turbine shaft 13, and a stator 5 that is connected to the transmission case 11 via a torque converter one-way clutch 6 and a connecting member 7.
The torque converter 2 drives the turbine 4 with the operating oil discharged from the pump 3 while rotating the turbine 4.
The process of rectifying the hydraulic oil discharged from the motor in a predetermined direction by the stator 5 and returning it to the pump 3 to assist the rotation of the pump 3 is repeated, and the torque of the engine output shaft 1 is reduced by the pump rotation speed and the turbine rotation speed. The speed is changed at a speed ratio according to the ratio and output to the turbine shaft 13. In the following, for convenience, the engine output shaft 1 side (the left side in FIG. 2) is referred to as “front” when viewed in the turbine shaft axis direction.
The opposite side (the right side in FIG. 2) is referred to as “rear”.

Further, the automatic transmission AT is provided with a transmission gear mechanism 10 for further shifting the torque of the turbine shaft 13 and outputting the torque to the drive wheels. This transmission gear mechanism 1
0 is an ordinary Ravigneaux type planetary gear set, which is substantially composed of a carrier 14, a small-diameter small sun gear 15,
Large diameter large sun gear 16 and long pinion gear 17
And a short pinion gear 18 and a ring gear 19. The transmission gear mechanism 10 includes:
The following various friction fastening elements are incorporated.

That is, a forward clutch 20 and a coast clutch 2 are provided between the turbine shaft 13 and the small sun gear 15 at the rear of the automatic transmission AT.
1 are arranged in parallel. Here, the forward clutch 20 interrupts power transmission from the turbine shaft 13 to the small sun gear 15 via the first one-way clutch 22. In addition, the coast clutch 21 is provided between the turbine shaft 13 and the small sun gear 1.
5, the power transmission between them is interrupted.

Outside the coast clutch 21 in the radial direction,
Brake drum 23a connected to large sun gear 16
And a 2-4 brake 23 comprising a brake band 23b applied to the brake drum 23a. Here, the large sun gear 16 is fixed when the 2-4 brake 23 is engaged.

Behind the 2-4 brake 23, a reverse clutch 24 for intermittently transmitting power between the large sun gear 16 and the turbine shaft 13 is provided. Further, between the carrier 14 and the transmission case 11, a low reverse brake 25 for intermittently connecting the carrier 14 and the transmission case 11 is provided, and a second one-way clutch 26 is connected in parallel with the low reverse brake 25. Are arranged.

Further, a 3-4 clutch 27 for intermittently transmitting power between the carrier 14 and the turbine shaft 13 is disposed slightly forward of the small sun gear 15. An output gear 28 is provided in front of the 3-4 clutch 27, and the output gear 28 is connected to the ring gear 19 via an output shaft 28a.

An oil pump 31 driven by the engine output shaft 1 is disposed behind the transmission gear mechanism 14 via a pump drive shaft 12 provided in a hollow portion of the tubular turbine shaft 13. Have been.

The transmission gear mechanism 10 having such a configuration
Has four forward speeds and one reverse speed, and each clutch 2
The desired gear stage can be obtained by appropriately operating the brakes 0, 21, 24, 27 and the brakes 23, 25. It should be noted that each shift speed and the clutches 20, 21, 2
Table 1 shows the operational relationship between the brakes 4, 27 and the brakes 23, 25.

[0019]

[Table 1]

The automatic transmission AT has a torque converter 2
Alternatively, a hydraulic mechanism 30 that supplies and discharges an operating oil pressure (operating oil) to and from the transmission gear mechanism 10 (the friction engagement element) is provided. The hydraulic mechanism 30 will be described below. The hydraulic mechanism 30 is controlled by a control unit C having a microcomputer. As shown in FIG. 3, the hydraulic mechanism 30, the operating oil discharged from the oil pump 31 is supplied to the oil passage L _1, hydraulic or line pressure of the oil passage L ₁ is regulated by the pressure regulator valve 32 It is being pressed. Here, the pressure regulator valve 32 is
It is controlled by a duty solenoid valve 33 in accordance with a signal applied from the control unit C. That is, the line pressure is controlled by the control unit C via the duty solenoid valve 33 in accordance with the operation state as described later (see FIG. 4).

[0021] Specifically, the hydraulic pressure in the oil passage L ₁ (line pressure)
Is reduced to a predetermined pressure by a reducing valve 34, and further regulated by a duty solenoid valve 33. This hydraulic pressure is supplied to a pressure regulator valve 32 as a pilot pressure, and a line pressure corresponding to the pilot pressure is applied to an oil passage L. ₁ is formed within. The pilot pressure is controlled by the control unit C
From the duty ratio applied to the duty solenoid valve 33. That is, hydraulic oil with pilot pressure is drained according to the duty ratio,
Thus, a pilot pressure corresponding to the duty ratio is formed.

The line pressure regulated by the pressure regulator valve 32 is supplied to the port of the manual valve 35.
supplied to g. The manual valve 35 is set to any one of the P, R, N, D, 2.1 ranges by a manual shift operation. Port g
Is connected (communicated) to ports a and e when the manual valve 35 is set to one range, is connected to ports a and c when it is set to two ranges, and is connected to ports a and c when it is set to D range. connected to a ・ c
When set to the R range, it communicates with port f.

The port a of the manual valve 35 is connected to the 1-2 shift valve 36 through an oil passage L _2. A pilot pressure controlled by a 1-2 solenoid valve 37 acts on the 1-2 shift valve 36. At the first speed, the 1-2 solenoid valve 3
7 are turned off, whereby the spool of the 1-2 shift valve 36 is disposed to the left position in FIG. 3, the oil passage L ₃ leading to the apply chamber 23c at this time the 2-4 brake 23 is connected to the drain port . In the second, third and fourth speeds, the 1-2 solenoid valve 37 is turned on, whereby the spool of the 1-2 shift valve 36 is disposed at the right side in FIG. It is supplied to the apply chamber 23c of the four brakes 23. Further, the 1-2 shift valve 36 supplies the hydraulic pressure (hydraulic oil) supplied from the port e of the manual valve 35 via the pressure reducing valve 38 to the low reverse brake 25 at the first speed in one range.

The hydraulic pressure at the port a of the manual valve 35 is also supplied to the 2-3 shift valve 39 as pilot pressure. The 2-3 shift valve 39 is connected to a port c of the manual valve 35 through an oil passage L _4, the pilot pressure is controlled by 2-3 solenoid valve 40. And in 1st and 2nd gear, 2-
The 3-solenoid valve 40 is turned on.
3 shift the spool of valve 39 is disposed to the right position in FIG. 3, this time the oil passage L ₅ leading to the 3-4 clutch 27 is connected to the drain port 3-4 clutch 27
Is released.

At the time of the third and fourth speeds, the 2-3 solenoid valve 40 is turned off, whereby the spool of the 2-3 shift valve 39 is disposed at the leftward position in FIG. It is supplied to the L ₅ 3-4
The clutch 27 is engaged. Oil passage L ₅ represents, also connected to the 3-4 shift valve 41, to the 3-4 shift valve 41, pilot pressure is controlled by a 3-4 solenoid valve 42 is applied. Then, at the 1st, 2nd and 4th speeds of the D range and at the 1st speed of the 2 range, 3-4
The solenoid valve 42 is turned on.
Spool of the shift valve 41 is disposed to the right position in FIG. 3, the oil passage L ₆ leading to the Lillies chamber 23d of the 2-4 brake 23 in this state is connected to the drain port.

Also, at the 3rd speed of the D range, at the 2nd speed,
During the third speed and during 1 range, 2 speed, is off 3-4 solenoid valve 42, whereby the spool of the 3-4 shift valve 41 is disposed to the left position in FIG. 3, this time the oil passage L ₆ When, is connected to an oil passage L ₅ which is connected to the 2-3 shift valve 39, hydraulic pressure is supplied and discharged with respect Lillies chamber 23d according to the state of the 2-3 shift valve 39. Additionally, 3-4 shift valve 41, by switching the intermittent between the oil passage L ₈ leading to the oil passage L ₇ and coast clutch 21 leading to the port a of the manual valve 35, the release-engagement of coast clutch 21 I do.

Each of the shift valves 36, 39, 41,
In the hydraulic circuit between the 2-4 brake 23 and the 3-4 clutch 27, the 1-2 accumulator 43, the 2-3 accumulator 44, the 2-3 timing valve 45, and the 3-2 for reducing shift shock and the like. A timing valve 46 and a bypass valve 47 are incorporated. The hydraulic mechanism 30 has a forward clutch 20 in the D, 2, 1 range.
River oil passage L ₉ to send the hydraulic pressure of the port a to the forward clutch 20 in order to fastening, a N-D accumulator 48 connected thereto, the oil pressure of the port f in order to conclude a reverse clutch 24 at the R range to Scratch 2
An oil passage L ₁₀ send to 4, and N-R accumulator 49 connected thereto, a lock-up control valve 50 for turning on and off the lock-up clutch 29, the lock-up solenoid valve 51 and the converter relief valve for controlling the 52 are provided.

The control unit C is a comprehensive control device for the automatic transmission AT or the hydraulic mechanism 30 including the "hydraulic control means" described in the claims. The predetermined control is performed using the throttle opening, the vehicle speed, and the like as control information. However, the general control of the automatic transmission AT or the hydraulic mechanism 30 is well known, and is not the gist of the present invention. Therefore, the description thereof will be omitted, and the operation state according to the gist of the present invention will be described below. Only the corresponding line pressure control of the hydraulic mechanism 30 will be described with reference to the flowchart shown in FIG.

In this line pressure control, the line pressure is basically controlled in accordance with the engine speed in the N range, while the line pressure is controlled in accordance with the throttle opening in the driving range such as the D range. When shifting from the N range to the D range, the line pressure in the N range immediately before the shift is maintained for a predetermined time.

When the control is started, first, in step # 1
Then, the range signal RNG, the engine speed Ne, and the throttle opening TVO are read as control information. next,
In step # 2, it is determined which range the current range signal RNG (t) is. If it is determined that RNG (t) is in the N range, the duty ratio DUTY is set in step # 8 according to the momentary engine speed Ne. The duty ratio DUTY in this case is stored in the memory of the control unit C as a function f (Ne) of the engine speed Ne. In this case, the characteristic of the duty ratio DUTY with respect to the engine speed Ne is set, for example, as shown in FIG.

Here, there is a linear function relationship between the duty ratio DUTY and the line pressure PL as shown in FIG. Therefore, in step # 8, the line pressure PL is preferably controlled in accordance with the engine speed Ne. Thereafter, the process returns to step # 1 to continue the line pressure control. As described later, the line pressure PL is controlled in accordance with the engine speed Ne in the N range at the time of the racing selection, that is, in the N range.
This is to prevent the occurrence of seizure or high temperature of the forward clutch 20 by sufficiently increasing the line pressure when the engine shifts to the D range and starts when the engine speed is increased in the range.

If it is determined in step # 2 that RNG (t) is in a range other than the N and D ranges, that is, in the 1, 2, and R ranges, in step # 7, the duty ratio DUTY is set to the throttle opening TVO. It is set according to. The duty ratio DUTY in this case is determined by the throttle opening TVO function g
(TVO) is stored in the memory of the control unit C. In this case, the duty DUTY
The characteristics of the throttle opening TVO are set, for example, as shown in FIG. As described above, the line pressure PL is controlled in accordance with the throttle opening TVO in the 1, 2, and R ranges because each of the friction engagement elements 20, 21, 23, 24, 25, and 2 is controlled.
This is for properly maintaining the fastening pressure of No. 7 according to the transmission torque and the like. Thereafter, the process returns to step # 1 to continue the line pressure control.

If it is determined in step # 2 that RNG (t) is in the D range, it is further determined in step # 3 which range the previous range signal RNG (t-Δt) was in. That is, in the present embodiment, when shifting from the N range to the D range, the line pressure PL in the N range immediately before the shift is held for a predetermined time ts, that is, the duty ratio DUTY is reduced to the engine speed N ₀ immediately before the shift. Corresponding to f (N ₀ ), the line pressure PL is set to a pressure corresponding to the engine speed so that the forward clutch 20 does not seize or become hot at the time of racing selection. In the D range, except for the above case, the line pressure PL is changed to the throttle opening TV.
It is set according to O.

Specifically, in step # 3, the previous RN
G (t-Δt) is if it is determined to be an N-range, the current time t is stored in step # 4, the value is set to t _0. Subsequently, in step # 5, the duty ratio DUTY
Is the engine speed N ₀ immediately before the shift from the N range to the D range, that is, a value f (N ₀ ) corresponding to the previous engine speed. Thereafter, the process returns to step # 1 to continue the line pressure control.

If it is determined in step # 3 that the previous RNG (t-.DELTA.t) was in the D range, the process proceeds to step # 6.
It is determined whether or not a predetermined time ts has elapsed after shifting to the D range. Here, if it is determined that the predetermined time ts has not elapsed (NO), the duty ratio DUTY is set to a value f corresponding to the engine speed N ₀ in step # 5.
(N ₀ ). Here, it is preferable that the predetermined time ts has a characteristic as shown in FIG. 8, for example, and is set to a larger value as the oil temperature is lower. However, when the oil temperature is low, the viscosity of the hydraulic oil is high, so that the pressure loss in the hydraulic mechanism 30 increases, and the hydraulic pressure applied to each friction engagement element decreases. Needless to say, the case is also included.

On the other hand, if it is determined in step # 6 that the predetermined time ts has elapsed after shifting to the D range,
(YES), in step # 7, the duty ratio DUTY is set according to the throttle opening TVO. Thereafter, the process returns to step # 1 to continue the line pressure control.

In step # 3, the previous RNG (t-
If Δt) is determined to be outside the N and D ranges, it means that no shift from the N range to the D range has occurred, and it is not necessary to hold the line pressure according to the engine speed for a predetermined time. Absent. Therefore, step # 7
Thus, the duty ratio DUTY is set according to the throttle opening TVO. Thereafter, the process returns to step # 1 to continue the line pressure control.

FIG. 9 shows that when such line pressure control is performed, the engine speed Ne (G ₁ ), turbine speed Nt (G ₂ ), and line pressure PL (G ₃ ) at the time of racing selection. The change characteristics of the forward clutch pressure (G ₄ ) and the forward clutch pressure (G ₅ ) in the conventional line pressure control with respect to time are shown. Note that in FIG. 9, time t ₀
Is shifted from the N range to the D range at time t ₁ , the forward clutch 20 starts to be engaged, and at time t ₂ , the line pressure control corresponding to the engine speed N ₀ is stopped, and the line pressure corresponding to the throttle opening TVO is reduced. Control has been started.

As is apparent from FIG. 9, in this embodiment, the forward clutch pressure (G ₄ ) is higher than that in the conventional case (G ₅ ), so that the forward clutch 20 slips even during the racing selection. Fastening is ensured in a short time without raising, and seizure or high temperature is reliably prevented.

It should be noted that the duty ratio DUTY is not held at f (N ₀ ) for the predetermined time ts, but is shifted from the N range to the D range. It may be set according to the rotation speed Ne. In this case, in the flowchart shown in FIG. 4, after deleting step # 8, step # 5 is set to DUTY ← f (Ne), and
If it is determined in step 2 that RNG (t) is in the N range, step # 5 may be executed.

[0041]

According to the first aspect of the invention, in the N range, the operating oil pressure is set in accordance with the engine speed so that the line pressure increases as the engine speed increases. The operating oil pressure is sufficiently increased, the time required for fastening the friction fastening element to be fastened at the time of starting is reduced, and seizure or high temperature of the friction fastening element is prevented. Further, when shifting from the N range to the D range, the operating oil pressure in the N range immediately before the shift is maintained for a predetermined time, so that the seizure or high temperature of the friction engagement element during the racing selection is reliably prevented. .

According to the second aspect, in the N range, the operating oil pressure is set in accordance with the engine speed so that the line pressure increases as the engine speed increases. And the time required for fastening the friction fastening element to be fastened at the time of starting is reduced, and seizure or high temperature of the friction fastening element is prevented. Further, when shifting from the N range to the D range, the line pressure control is performed for a predetermined time in accordance with the engine speed, so that the seizure or high temperature of the friction engagement element during the racing selection is reliably prevented. You.

[0043]

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of the first and second aspects of the present invention corresponding to claims 1 and 2;

FIG. 2 is a system configuration diagram of the automatic transmission according to the present invention.

FIG. 3 is a system configuration diagram of a hydraulic mechanism of the automatic transmission according to the present invention.

FIG. 4 is a flowchart illustrating a control method of line pressure control.

FIG. 5 is a diagram showing characteristics of a line pressure with respect to a duty ratio.

FIG. 6 is a diagram showing characteristics of a duty ratio with respect to an engine speed.

FIG. 7 is a diagram showing a characteristic of a duty ratio with respect to a throttle opening.

FIG. 8 is a diagram showing a characteristic with respect to an oil temperature of a time during which line pressure control according to an engine speed is to be continued when shifting from an N range to a D range.

FIG. 9 is a diagram showing a change characteristic of an engine speed, a turbine speed, a line pressure, and a forward clutch pressure with respect to time during a racing select.

[Explanation of symbols]

 AT: Automatic transmission C: Control unit 10: Transmission gear mechanism 20: Forward clutch 21: Coast clutch 23: 2-4 brake 24: Reverse clutch 25: Low reverse brake 27: 3-4 clutch 30: Hydraulic mechanism

────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hiroshi Shinozuka 3-1, Shinchi, Fuchu-cho, Aki-gun, Hiroshima Prefecture Mazda Co., Ltd. (56) References JP-A-5-99315 (JP, A) Japanese Utility Model 4 −68246 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) F16H 61/00-61/24

Claims (2)

(57) [Claims] An automatic transmission control device provided with a plurality of frictional engagement elements and a hydraulic mechanism for operating the frictional engagement elements, wherein the control apparatus is adapted to correspond at least to the engine speed in a neutral range. The operating oil pressure of the hydraulic mechanism is controlled so that the line pressure increases as the pressure increases, and when the automatic transmission is shifted from the neutral range to the drive range, the operating oil pressure in the neutral range immediately before the shift is maintained even after the shift. A control device for an automatic transmission, further comprising a hydraulic control means for holding only for a time. 2. A control device for an automatic transmission, comprising: a plurality of frictional engagement elements; and a hydraulic mechanism for operating the frictional engagement elements. The hydraulic pressure of the hydraulic mechanism is controlled so that the line pressure increases as the pressure increases, and when the automatic transmission is shifted from the neutral range to the drive range, the hydraulic pressure is adjusted in correspondence with the engine speed for a predetermined time after the shift. A control device for an automatic transmission, comprising: hydraulic control means for controlling an operating hydraulic pressure of a mechanism.