JPH02118263A - Device for controlling speed change of automatic transmission - Google Patents

Abstract

PURPOSE:To reduce speed change shock by controlling shift valves so as to form a defined speed change stage in a condition of no engaging pressure acting on an apply chamber when a throttle valve opening becomes above a defined small opening value in a defined speed change stage. CONSTITUTION:When a throttle valve opening becomes above a set small opening value in a defined speed change stage, a valve control means 56 discharges engaging pressure in the apply chamber 35b of a hydraulic actuator 35 and, at this time, when shift down is demanded, releasing pressure in a release chamber 35c is discharged while the engaging pressure in the apply chamber 35b is gradually increased, smoothly engaging a brake element 18 to lower a speed change shock. On the other hand, when the opening is below the set small opening, the engaging pressure is previously applied in the apply chamber 35b and a brake element 18 is kept in a released condition by the releasing pressure of a release chamber 35c and, at the time of demanding shift down, the releasing pressure of the release chamber 35c is discharged and, at this time, a clutch element 24 is immediately engaged by the engaging pressure which is previously applied to the apply chamber 35b, causing engine brake to promptly act while restraining the idle traveling feeling of a vehicle.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an improvement in a shift control device for an automatic transmission, and more particularly to measures to reduce the feeling of idling in a vehicle and shift shock that occurs during gear shifts.

(Prior Art) Conventionally, as a shift control device for an automatic transmission, one disclosed in, for example, Japanese Unexamined Patent Publication No. 62-233547 has been known. This gear mechanism includes a clutch element and a brake element as transmission elements, and has a basic configuration in which the clutch element is controlled to be engaged and the brake element is controlled to be released when a predetermined gear is established. The hydraulic actuator controls the brake element, and applies release pressure to a release chamber of the hydraulic actuator to control the release of the brake element, releases the release pressure of the release chamber, and connects the brake element to the apply chamber. It has a configuration that applies pressure to control the engagement of the brake element.

When the brake element is engaged to downshift to a lower gear, the brake element is tightened to prevent the vehicle from feeling like it is running idle due to the gear being temporarily in a neutral state when downshifting from a high vehicle speed. The following configuration has been adopted to increase the engagement responsiveness of the brake system while effectively reducing shift shock by smoothly engaging the brake elements when downshifting from low vehicle speeds. In other words, when the release pressure is acting on the release chamber of the hydraulic actuator, the brake element is controlled to open regardless of the effect or inaction of the engagement pressure in the apply chamber. At the gear stage, if the vehicle speed is higher than a set value, apply pressure is applied to the apply chamber in advance, and when downshifting from this high vehicle speed, the release pressure in the release chamber is discharged. As a result, the brake element is immediately engaged using the engagement pressure in the apply chamber, thereby increasing the engagement responsiveness of the brake element and preventing the vehicle from feeling like it is running idly during downshifting. On the other hand, at low vehicle speeds, the brake element is gradually engaged by introducing engagement pressure into the apply chamber for the first time at the time of downshifting, without performing control to apply engagement pressure to the apply chamber in advance, thereby reducing shift shock. It is said that

(Problem to be Solved by the Invention) However, in the above conventional system, the speed at which the brake element is engaged during downshifting changes depending on the vehicle speed, and is fast at high vehicle speeds (but gradually at low vehicle speeds). In relation,
Even though the gears are downshifting from the same gear position, the gears are not shifted in the same way, giving the driver a sense of discomfort. Moreover, when the driver changes the range position of the select lever to apply engine braking, it is necessary to downshift quickly and in a short time to effectively decelerate regardless of the vehicle speed, but at low vehicle speeds Since the elements are gradually tightened, there is a drawback that the driver feels that the vehicle is running idle.

The present invention has been made in view of the above problems, and its purpose is to eliminate the strange feeling given to the driver when downshifting, and to always change the range when changing ranges (when requesting engine braking to be applied). By fastening the brake element,
The purpose is to suppress the feeling of the vehicle running idle.

(Means for Solving the Problems) In order to achieve the above object, the present invention has two types of cases: a case in which accelerated operation is required even when downshifting, and a case in which engine braking effectiveness is requested by range switching. We focused on the fact that this driving requirement is expressed in the driver's depression of the accelerator pedal, and in the former case the amount of depression is large, while in the latter case only the select lever is operated and the amount of accelerator pedal depression is extremely small. From this point of view, when the opening of the throttle valve is relatively large (when accelerating operation is required), the braking element engagement speed during downshifting is always the same to eliminate the strange feeling given to the driver. With,
When the throttle valve opening degree is extremely small (when engine braking effectiveness is required), the engagement speed of the brake element is increased to effectively suppress the feeling of idle running of the vehicle.

That is, the specific configuration of the present invention, as shown in FIG. 1, includes a clutch element 24 and a brake element 18 as transmission elements of a transmission gear mechanism, and a fastening operation of the clutch element 24 and a releasing operation of the brake element 18. This assumes an automatic transmission that configures a predetermined gear position. A hydraulic actuator 35 for controlling the brake element 18 is provided,
The configuration of the hydraulic actuator 35 is changed to the apply chamber 35b.
and a release chamber 35c, and the release chamber 35c.
The brake element 18 is configured to be controlled to the release side when a release pressure is applied to the brake element 18. Further, shift valves 32 and 40° 45 are provided to control the action of hydraulic pressure on the clutch element 24 and the hydraulic actuator 35. Further, an opening detection means 55 is provided for detecting the opening of the throttle valve, and the output of the opening detection means 55 is received, and when the throttle valve opening is less than or equal to the preset small opening value at the predetermined gear position, the The predetermined gear stage is configured in a state in which the engagement pressure is applied to the apply chamber 35b, and when the throttle valve opening exceeds the set small opening value at the predetermined gear position, the engagement pressure is not applied to the apply chamber 35b. A valve control means 56 is provided for controlling the shift valve 32.40.45 so as to configure the predetermined gear position.

(Function) With the above configuration, in the present invention, when a predetermined gear stage is configured, the clutch element 24 is engaged by hydraulic pressure, and the release chamber 35c of the hydraulic actuator 35 is released. pressure is introduced into the brake element 1
8 is in open operation.

Now, when the throttle valve opening exceeds the set small opening value at the above-mentioned predetermined gear stage, the apply chamber 35b of the hydraulic actuator 35 is adjusted by the valve control means 56 to a state where the engagement pressure is exhausted. Therefore, if a downshift is requested in this situation, it can be determined that acceleration operation is requested based on the relatively large opening, and in this case, the release pressure in the release chamber 35e of the hydraulic actuator 35 is exhausted. At the same time, oil is started to be introduced into the apply chamber 35b, and the fastening pressure gradually increases. As a result, the brake element 18 is smoothly engaged, and the shift shock is effectively reduced. Here, when this acceleration is requested, the brake element 18 is gradually engaged regardless of the vehicle speed, so the engagement speed does not change depending on the vehicle speed as in the conventional case, and the strange feeling given to the driver can be eliminated.

On the other hand, when the throttle valve opening is less than the set small opening value, oil is supplied to the apply chamber 35b of the hydraulic actuator 35 by the valve control means 56, and a fastening pressure is applied in advance. In this case, the brake element 18 maintains the opening operation due to the release pressure of the release chamber 35e. Therefore, when a downshift is requested at this minute opening, that is, when the driver changes the range and requests engine braking to be applied, the release chamber 35c of the hydraulic actuator 35
The release pressure is exhausted, and at this point the apply chamber 35b
Since the brake element 24 is immediately engaged by the engagement pressure that is applied in advance to the brake element 24, its engagement responsiveness is increased, the downshift is immediately completed, the engine brake is immediately applied, and the feeling of the vehicle running idly is sufficiently suppressed. be done.

(Effects of the Invention) As explained above, according to the shift control device for an automatic transmission according to the present invention, when downshifting is required to perform acceleration operation from a state where the throttle valve opening is relatively large at a predetermined gear position, Since the brake elements are always engaged smoothly regardless of the vehicle speed, the shift shock during downshifting is effectively reduced, and the driver's In addition, when the throttle valve opening is extremely small at a given gear stage and the engine brake is required to be effective by changing the range, the tightening pressure applied in advance to the application chamber of the hydraulic actuator can be used. Since the brake element is thus quickly engaged, the engagement responsiveness of the brake element can be improved, and the feeling that the vehicle is running idly, which is given to the driver when downshifting, can be eliminated.

Moreover, it is possible to quickly downshift in response to the driver's intention to change the driving range, thereby improving the driving feeling.

(Example) Hereinafter, an example of the present invention will be described based on the drawings from FIG. 2 onwards.

FIG. 2 shows an automatic transmission with four forward speeds and one reverse speed, and 1 is an engine output shaft, and 2 is a pump 2a connected to the engine output shaft 1, a stator 2b, and a turbine 2c. The stator 2b of the torque converter is fixed to a case 4 via a one-way clutch 3 that prevents the stator 2b from rotating in the opposite direction to the turbine 2c. Further, 5 is a speed change gear device connected to a converter output shaft 2d connected to the turbine 2c of the torque converter 2.

The speed change gear device 5 is provided with a Ravigneau type planetary gear mechanism 7 inside, and the planetary gear mechanism 7 includes a small diameter sun gear 8 and a large diameter sun gear 9 arranged in the front and rear, and the small diameter sun gear 8.
The long pinion gear 11 meshes with the large diameter sun gear 9 and the short pinion gear 10, and the ring gear 12 meshes with the long pinion gear 11. Above small diameter sun gear 8
is connected to the forward clutch 15 disposed behind it and the converter output shaft 2 connected in series to the clutch 15.
a first one-way clutch 16 that prevents reverse drive of d; and a coast clutch 17 connected in parallel with these clutches.
It is connected to the output shaft 2d of the torque converter 2 via. The large diameter sun gear 9 also includes a 2-4 brake 18 and a 2-4 brake 18 arranged diagonally rearward thereof.
The torque converter 2 is connected to the output shaft 2d of the torque converter 2 via a reverse clutch 19 arranged at the rear of the torque converter 2. Furthermore, the long pinion gear 11 is provided with a low & reverse brake 21 that fixes the long pinion gear 11 via its rear carrier 20, and a
A second one-way clutch 22 that allows rotation in the same direction as the engine output shaft 1 is connected in parallel, and
The front carrier 23 is connected to the output shaft 2d of the torque converter 2 via a 3-4 clutch 24. Further, the ring gear 12 is connected to an output gear 25 disposed in front of the ring gear 12. In addition, in the figure, 27
28 is a lock-up clutch that directly connects the engine output shaft 1 and the converter output shaft 2d, and 28 is an oil pump driven by the engine output shaft 1 via an intermediate shaft 29.

In the above configuration, the operating states of each clutch and brake at each gear stage are shown in the table below.

Thus, 2-4 brake (brake element) 18 and 3-
As can be seen from the above table, the 4 clutch (clutch element) 24 is controlled to the engagement side at the D and 2 range positions, and at the 3rd forward speed (predetermined gear stage). , 2-4 brake 18 is controlled to the open side.

Next, FIG. 3 shows a hydraulic control circuit for controlling the engagement/disengagement of each of the above elements. In the figure, 30 is a pressure regulating valve that regulates the oil pressure from the oil pump 28 to generate a line pressure proportional to the throttle valve opening, and 31 is the line pressure of the line pressure generated by the pressure regulating valve 30. It is a manual valve connected to the passage 32.

Further, 32 is a 1-2 shift valve, and the valve 32 is a 1-2 shift valve.
2 has a 1-2 solenoid 5OLI, and when the 1-2 solenoid 5OLI is turned ON, the servo is turned ON so as to connect the oil pipe 33 to the oil pipe 34, and the line pressure is passed through the pipe 34 to control the 2-4 brake 18. Mechanism (hydraulic actuator)
35 into the apply chamber 35b.

The internal configuration of the servo mechanism 35 is as follows: 2-4 brake 18
a piston 35a connected to via a rod 18a;
A hydraulic apply chamber 35b and a release chamber 35c are divided vertically in the figure by the piston 35a, and the piston 35a is compressed into the release chamber 35c.
It has a spring 35d that biases it toward the side. The pressure receiving area of the piston 35a is the release chamber 35.
C is larger and the apply chamber 35b is smaller, and due to the difference in pressure receiving area, the apply chamber 35b is smaller.
Effect of tightening pressure (line pressure) in 5b.

Regardless of whether it is inactive or not, if release pressure (line pressure) acts on the release chamber 35b, the release pressure and the urging force of the spring 35d move the piston 35a upward in the figure.
The configuration is such that the 2-4 brake 13 is operated to the release side. Therefore, when the 2-4 brake 18 is requested to be engaged, the engagement pressure is introduced into the apply chamber 35b and the release chamber 35c is
By discharging the release pressure, the piston 35c is moved downward in the figure, and the 2-4 brake 18 is engaged.

Further, a piston-type accumulator 37 is disposed in the oil pipe 34 communicating with the apply chamber 35b of the servo mechanism 35 to suppress a sudden increase in the oil pressure value of the fastening pressure to the apply chamber 35b. The accumulator 37 has a piston 37a.
, an oil chamber 37b into which oil from the oil pipe 34 flows to move the piston 37a leftward in the figure, and a spring 37c compressed in the oil chamber 37b.
Back pressure (line pressure) acts via 8.

Further, 40 is a 2-3 shift valve that controls the action of oil pressure on the 3-4 clutch 24;
3 solenoids 5OL2, the 2-3 solenoids 5O
O so that oil pipe 41 communicates with oil pipe 42 when L2 is OFF.
N is activated and the line pressure (clamping pressure) is passed through the oil pipe 42 to 3-4.
This is introduced into the clutch 24.

Similarly, 45 is the coast clutch 17 and the sabot mechanism 35
The valve 45 is a 3-4 shift valve that controls the action of hydraulic pressure on the release chamber 35c, and the valve 45 has a 3-4 solenoid 5OL3, and the 3-4 solenoid 5OL3 is turned OFF.
At the same time, the oil pipe 46 is connected to the oil pipe 47 to increase line pressure (clamping pressure).
is introduced into the coast clutch 17 via the oil pipe 47, and the oil pipe 48 connected to the oil pipe 42 communicating with the 3-4 clutch 24 is turned ON so as to communicate with the oil pipe 49.
Line pressure (release pressure) is passed through oil pipe 49 to 2-4 brake 2
4 into the release chamber 35c of the servo mechanism 35.

Further, the forward clutch 15 is connected to the piping 50°46.3
It communicates with the manual valve 31 through 3, and 2.
Line pressure (clamping pressure) is always introduced at each forward travel range position of 1.

Next, shift control will be explained based on the control flow shown in FIG. 4.

Start, step S! After reading the throttle valve opening θ, vehicle speed ■, and range signal in step S2, the current driving state is compared with a pre-stored shift pattern to determine whether or not it is time to shift. If the gear is not being shifted, the current gear is determined in step S3, and if it is the third gear (predetermined gear), the throttle valve opening θ is determined in step S4.
Set a small opening value (for example, 1/8 opening value when fully opened, in the area below this ■/8 opening value, no downshift will occur regardless of the opening value, and if the opening value is 1/8 or more) When the opening angle is relatively large (θ≧178), step S5 2-4 brake 18 by controlling each shift valve 32.40°45 to select the first pattern in the following table.
The third speed is configured in a state where no fastening pressure is introduced into the apply chamber 35b of the servo mechanism 35. In addition, in the case of a small opening of θ < l/l, each shift is made to select the second pattern in the following table in step S6 in order to cope with the driver's request for a downshift to apply engine braking due to range switching. The third speed is established by controlling the valves 32, 40, 45, and in a state in which a fastening pressure (line pressure) is introduced into the apply chamber 35b of the servo mechanism 35 in advance.

If the gear is being shifted in step S2, it is further determined in step S7 whether or not the gear is being shifted from 3 to 2 (downshifting), and if it is being shifted in any other gear, the shift light is turned off in step S8. Each shift valve 32, 40, 45 is controlled to shift to a gear position.

On the other hand, when the 3-2 gear shift is performed in step S7, the throttle valve opening degree θ is determined in step S9, and when the opening degree is small such that θ<l/8, the downshift is terminated early and the engine brake is applied immediately. Step SIG immediately.
The shift valve is controlled to proceed to the second speed and configure the second gear. On the other hand, at a relatively large opening of p≧l/8, 2-
4. In order to gradually engage the brake 18 and shift gears with less shock, the control pattern is switched to the first pattern for the 3rd speed in the table above in step Sl+, and -2 shift valve 3
2 to OFF and the apply chamber 35 of the servo mechanism 35
By opening b, a state in which no fastening pressure is applied is created.

Then, in step S12, a total Jl (countdown) of timer 1 (for example, 0.4 seconds) is started, and in step SI3, if timer 1≧0 has not elapsed, step S
After inputting the vehicle speed V and throttle valve opening θ again at H,
In step SI5, it is determined whether or not these have exceeded the 3-2 down map line on the shift pattern, and if the line has been exceeded, the shift valve is immediately controlled in step 810 to configure the second speed.

On the other hand, when the timer is 1 to 0, the increase in the throttle valve opening θ is gradual and the line pressure is also small, so 3→
2 Apply chamber 35b of servo mechanism 35 during downshift
Even if engagement pressure (line pressure) is applied to the clutch, the upward change (rise of oil pressure) is slow and the engagement of the 2-4 brake 18 is delayed, and together with the open state of the 3-4 clutch 24, the gear shift is delayed. becomes neutral to prevent a temporary increase in engine speed (drift).

In other words, after monitoring the vehicle speed V and throttle valve opening θ in step SI6, if it is determined in step S17 that the 3-2 down map line has been exceeded, then in step S18 the above table is temporarily Taking the second pattern in the third speed, the application chamber 35 of the hydraulic actuator 35 is
A fastening pressure (line pressure) is applied to b in advance (. Then, in step S19, the continuation time is set to timer 2 (for example, 0
．． 3 seconds), the timer 2 counts down in step 82G, and if it has not elapsed yet, the throttle valve opening θ is monitored again in step S21, and this opening is determined in step S22. When θ is a relatively large opening value (for example, 378 opening value), the line pressure has increased sufficiently, so the second gear is set in step SIG without waiting for timer 2 to elapse. . On the other hand, as soon as the timer 2 elapses in step S20, the second gear is established in step 5i11, and the process ends.

Therefore, in the control flow of FIG. 4 above, step S
1 constitutes an opening detecting means 55 that detects the opening of the throttle valve.

Further, in steps 84 to S6, the opening degree detection means 5
5, and when the throttle valve opening θ is less than the set small opening value (l/8 opening value) at the third gear, the second pattern in the table above is adopted and the hydraulic actuator 35 is activated. The third speed is configured in a state where the fastening pressure is applied to the apply chamber 35b, and on the other hand, the throttle valve opening θ is set at the third speed.
exceeds the 1/8 opening value, the shift valve 32 adopts the first pattern in the table above and configures the third gear with no engagement pressure acting on the apply chamber 35b.
．． 40. Valve control means 56 adapted to control 45.
It consists of

Therefore, in the above embodiment, in the third forward speed, the 3-4 shift valve 45 operates o+:p and release pressure acts on the release chamber 35e of the servo mechanism 35, so that the 2-4 brake 18 will be released. Further, since the 2-3 shift valve 40 is operated OP, the 3-4 clutch 24 is engaged by engagement pressure.

Therefore, if the throttle valve opening θ exceeds the opening value θ≧l/8 at the third gear, as shown in FIG. 5 (a).
As shown in FIG. 2, by turning off the l-2 shift valve 32, the apply chamber 35b of the hydraulic actuator 35 is opened, and no fastening pressure (line pressure) is applied thereto. As a result, in this situation, if a downshift is requested beyond the 3→2 down map line, it can be determined that accelerating operation is requested because the throttle valve opening θ is relatively large, and at the time of this downshift request, As the release pressure in the release chamber 35c of the hydraulic actuator 35 is discharged, the engagement pressure starts acting on the apply chamber 35b, so this engagement pressure gradually rises and the 2-4 brake 18 slips. , the torque change on the engine output shaft is reduced, and the second gear is configured with less shift shock.

At this time, the situation in which the driver requests acceleration operation is a situation in which the throttle valve opening θ always exceeds the set small opening value (l/8 opening value), and in this situation, the 2-4 brake 18 is always activated. Since the 2-4 brake 18 is engaged gradually and the engagement speed is the same regardless of the vehicle speed, it is possible to eliminate the sense of discomfort that the driver feels due to the change in the engagement speed of the 2-4 brake 18 as in the past.

Moreover, if the increase in the throttle valve opening θ is slow as shown in FIG. In this case, the engagement pressure is introduced into the apply chamber 35b only during the timer 2 at the third gear, and then the release pressure in the release chamber 35c is exhausted and the second
Since the above-mentioned gear positions are configured, the engagement of the 2-4 brake 18 can be accelerated even when the line pressure is at a small value, thereby effectively suppressing the occurrence of the above-mentioned engine racing phenomenon.

Also, at the third gear, the throttle valve opening θ is θ<
In the case of a minute opening of 1/8 or less, a fastening pressure (line pressure) acts on the apply chamber 35b of the hydraulic actuator 35 in advance. As a result, when a downshift is requested in this situation, that is, when the driver operates the select lever to change the range and request the effectiveness of the engine brake, the release chamber 3 of the hydraulic actuator 35
When the release pressure acting on the apply chamber 35b is discharged, the 2-4 brake 18 is immediately engaged by the engagement pressure acting on the apply chamber 35b, so that the second gear can be changed in a short time. With this configuration, the engine output shaft becomes effective immediately, and the feeling of idle running of the vehicle given to the driver can be effectively suppressed. Moreover, in response to the driver's intention to change the range and request the effectiveness of the engine brake, the 2-4 brake 18
can be fastened quickly, so it is possible to improve the driving feeling given to the driver.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the configuration of the present invention. Figures 2 to 5 show embodiments of the present invention, in which Figure 2 is a skeleton diagram of an automatic transmission, Figure 3 is a hydraulic circuit diagram, and Figure 4 is a hydraulic circuit diagram.
The figure is a flowchart of speed change control, and FIG. 5 is an operation explanatory diagram. 18...2-4 brake (brake element), 24...
・3-4 clutch (clutch element), 35... Servo mechanism (hydraulic actuator), 35b... Apply chamber, 35c... Release chamber, 5OLI-9OLI...
Solenoid, 32...1-2 shift valve, 40...
-2-3 shift valve, 45...3-4 shift valve, 55...opening detection means, 56...valve control means. (a) (b) Figure

Claims (1)

[Claims] (1) In an automatic transmission that includes a clutch element and a brake element as the transmission elements of a transmission gear mechanism, and configures a predetermined gear stage by the engagement operation of the clutch element and the release operation of the brake element, hydraulic pressure for controlling the brake element. an actuator, the hydraulic actuator having an apply chamber and a release chamber, and configured to control the brake element to the open side when release pressure is applied to the release chamber, and the clutch element and the hydraulic actuator a shift valve for controlling the effect of hydraulic pressure on the throttle valve; an opening detection means for detecting the opening of the throttle valve; and an opening detection means for detecting the opening of the throttle valve; When the throttle valve opening exceeds the preset small opening value at the predetermined gear, the engagement pressure is applied to the apply chamber. A shift control device for an automatic transmission, comprising: valve control means for controlling the shift valve to configure the predetermined gear position in a state in which the shift valve does not operate.