JP3510193B2 - Hydraulic 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 hydraulic control device for a continuously variable automatic transmission or the like.

[0002]

2. Description of the Related Art In a continuously variable automatic transmission incorporating a belt type continuously variable transmission mechanism, a starting clutch, which is a hydraulic coupling element, is provided in series with the continuously variable transmission mechanism, and a creep function and torque are provided by slip control of the starting clutch. A torque limiter function is provided to prevent belt slip during a sudden increase.
For that purpose, it is necessary to accurately control the hydraulic pressure supplied to the starting clutch. Therefore, conventionally, there is known one in which the hydraulic pressure supplied to the starting clutch is regulated by a pressure regulating valve controlled by a linear solenoid valve (see Japanese Patent Application Laid-Open No. 10-252850).

[0003]

By the way, when the friction material of the starting clutch is abraded or the oil of the transmission is deteriorated, stick slip of the starting clutch occurs during slip control of the starting clutch, which is caused by this. Torque fluctuation of the drive system, so-called judder may occur. When the judder occurs, the hydraulic pressure of the starting clutch fluctuates, and this hydraulic pressure fluctuation is transmitted to the linear solenoid valve via the pressure regulating valve, causing vibration of the linear solenoid valve. Here, the change characteristic of the output hydraulic pressure P with respect to the energizing current value I of the linear solenoid valve is shown in FIG.
The area shown by A in the drawing where the linear characteristic is obtained is used as a control area which requires particularly accuracy in order to secure drivability. However,
If the linear solenoid valve continues to be vibrated by the judder, the region where the linear characteristic is obtained is sandwiched by the range B in the figure, and the drivability deteriorates.

In view of the above points, it is an object of the present invention to provide a hydraulic control device for an automatic transmission which can suppress the vibration of the linear solenoid valve due to judder.

[0005]

[Means for Solving the Problems] In order to solve the above problems,
According to the present invention, the hydraulic pressure supplied to the hydraulic coupling element provided in the automatic transmission is controlled by the relationship between the applied current value and the output hydraulic pressure.
In a hydraulic control device for an automatic transmission that regulates pressure with a pressure regulating valve that is controlled by a linear solenoid valve with a control system that prevents vibration of the linear solenoid valve in an oil passage that inputs the output hydraulic pressure of the linear solenoid valve to the pressure regulating valve. The accumulator is connected. The accumulator is located in the oil chamber of the pressure regulating valve.
Installed in a small volume that can absorb hydraulic pressure fluctuations due to volume changes.
Can be set. Also, the back pressure pressure of the accumulator
The pulling can be composed of multiple stages of springs.

When the hydraulic pressure of the hydraulic connecting element fluctuates due to judder, the hydraulic pressure fluctuation is transmitted to the oil passage for inputting the output hydraulic pressure of the linear solenoid valve to the pressure regulating valve through the pressure regulating valve.
According to the present invention, the hydraulic pressure fluctuation is absorbed by the accumulator connected to this oil passage, and the vibration of the linear solenoid valve is suppressed.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION Referring to FIG. 1, 1 is an engine,
Reference numeral 2 denotes an automatic transmission, which comprises _first to third three shafts 3 ₁ , 3 ₂ and 3 ₃ arranged in parallel, and the first shaft 3 ₁ via a damper 4. The third shaft 3 ₃ is connected to the drive wheels (not shown) of the vehicle via the differential gear 5 as well as to the engine 1.

A belt type continuously variable transmission mechanism 6 is provided between the first shaft 3 ₁ and the second shaft 3 ₂ . The continuously variable transmission mechanism 6
Is a drive pulley 60 pivotally supported on the first shaft 3 ₁ ,
Driven pulley 61 fixed to shaft 3 ₂ and both pulleys 6
It is composed of a belt 62 wound around 0, 61,
The internal pressure of the hydraulic cylinders 60b and 61b that press the movable sheaves 60a and 61a of the pulleys 60 and 61 is controlled to change the winding diameter of the belt 62 around the pulleys 60 and 61 to perform continuously variable transmission.

On the input side of the continuously variable transmission mechanism 6, there is provided a forward / rearward travel switching mechanism 7 which connects the drive pulley 60 to the first shaft 3 _1. Also, on the output side of the continuously variable transmission mechanism 7, a second drive mechanism is provided. Axis 3
_A starting clutch 8 is provided as a hydraulic connecting element that connects ₂ to the third shaft 3 ₃ . In the figure, 9 is a parking gear.

[0010] forward-reverse switching mechanism 7 includes a sun gear 70 fixed to the first shaft 3 _1, a ring gear 7 which is pivotally supported by the first shaft 3 ₁
1, a planetary gear 72 that meshes with the sun gear 70 and the ring gear 71, and a carrier 73 that carries the planetary gear 72 and that is connected to the drive pulley 60. The single-pinion planetary gear mechanism is configured. Then, a forward clutch 74 for connecting the carrier 73 to the first shaft 3 _1, provided a reverse brake 75 to stop the rotation of the ring gear 71, the drive pulley 60 when turning on the forward clutch 74 is forward, The power is transmitted in the forward direction, and when the reverse brake 75 is turned on, the drive pulley 60 is rotated in the reverse direction so that the power is transmitted in the reverse direction.

The hydraulic control device for the automatic transmission 2 is shown in FIG.
As shown in, a hydraulic pump 10 driven by the engine 1
And a first regulator valve 11 that outputs a first pulley control pressure (hereinafter referred to as PH pressure) using the discharge hydraulic pressure of the hydraulic pump 10 as a source pressure, and a second regulator valve 11 that has a PH pressure as a source pressure and is lower than the PH pressure. Second regulator valve 12 that outputs a pulley control pressure (hereinafter, referred to as PL pressure) of the drive pulley 60, and PH pressure and PL pressure to and from one of the hydraulic cylinder 60b of the drive pulley 60 and the hydraulic cylinder 61b of the driven pulley 61. To the drive pulley 60 and the driven pulley 61. The shift control valve 13 supplies the shift control valve 13 and the first linear solenoid valve 14 that controls the shift control valve 13.
The pressure difference between 0b and 61b is controlled by the first linear solenoid valve 14 via the shift control valve 13 to perform continuously variable shifting.

By the way, the PL pressure should be set as low as possible within a range where belt slip does not occur in order to reduce friction loss at the belt entry point and the belt departure point of the pulley. Therefore, a second linear solenoid valve 15 for controlling the second regulator valve 12 is provided so that the PL pressure can be increased / decreased by the second linear solenoid valve 15 according to the output torque of the engine 1 via the second regulator valve 12. I have to. In addition, the first regulator valve 11 is
A main valve 110 provided in an oil passage connected to the hydraulic pump 10,
The auxiliary valve 111 is provided in an oil passage for feeding back the PH pressure to the main valve 110 and is capable of leaking the feedback pressure. The auxiliary valve 111 serves as the second linear solenoid valve 1
The output hydraulic pressure of 5 is applied to the non-leak side to keep the PH pressure higher than the PL pressure by a constant pressure. The first and second linear solenoid valves 14 and 15 described above are
Using the modulator pressure (constant pressure lower than PH pressure) from the modulator valve 16 provided in the oil passage branched from the oil passage supplying the H pressure to the shift control valve 13 as the original pressure, The hydraulic pressure is output according to the current value of the solenoids 14a and 15a. The leak oil from the first regulator valve 11 is supplied to the lubrication system 17 of the automatic transmission 2 and also to the oil cooler 19 via the lubrication regulator valve 18.

The hydraulic control system further includes a forward clutch 7
4 and the reverse brake 75, a manual valve 20 for controlling the oil supply and discharge, and a pressure regulating valve 2 for regulating the hydraulic pressure of the starting clutch 8.
1 and are provided. The manual valve 20 has a parking "P", a reverse "R", a neutral "N", a forward normal travel "D", a sporty travel "S", and a low speed hold. It is possible to switch between 6 positions with "L" for supplying the modulator pressure to the reverse brake 75 at the "R" position, and to supply the modulator pressure to the forward clutch 74 at the "D""S""L" positions. Is configured to. Further, a reverse inhibitor valve 22 which can be freely opened and closed is provided in an oil passage between the reverse brake 75 and the manual valve 20. The reverse-travel inhibitor valve 22 is provided with an oil chamber 22a at the right end that presses it toward the left side opening side.
Is provided with a solenoid valve 23 that can be switched to a state in which the
While the vehicle is moving forward, the solenoid valve 23 opens the oil chamber 22a to the atmosphere, and the reverse inhibitor valve 22 is closed. The hydraulic pressure to the reverse brake 75 when the manual valve 20 is switched to the "R" position during traveling forward. We are trying to prevent supply. When the manual valve 20 is switched to the “R” position after the vehicle has stopped, the solenoid valve 23 inputs the modulator pressure into the oil chamber 22a, the reverse inhibitor valve 22 is opened, and the reverse brake 75 is supplied with hydraulic pressure. To be done.

The auxiliary valve 111 of the first regulator valve 11 is provided with an oil chamber 111a for pressing the auxiliary valve 111 toward the leak side, and the oil chamber 111a is provided with the oil chamber 22 of the reverse drive inhibitor valve 22.
Similar to a, it is connected to the oil passage on the output side of the solenoid valve 23, and when the solenoid valve 23 outputs the modulator pressure that is the signal pressure for opening the reverse drive inhibitor valve 22 during reverse travel, the first pressure is supplied via the auxiliary valve 111. The feedback pressure input to the main valve 110 of the regulator valve 11 is reduced, and the PH pressure is reduced accordingly. Here, the gear ratio in the forward / reverse switching mechanism 7 is 1.0 when the vehicle is moving forward when the forward clutch 74 is engaged, but is larger than 1.0 when the vehicle is moving backward when the reverse brake 75 is engaged, and deceleration is performed. . When the vehicle starts moving, the shift control valve 1
3 is PH to the hydraulic cylinder 61b of the driven pulley 61.
Since it is in the LOW position (the position shown in the figure) that supplies the PL pressure to the hydraulic cylinder 60b of the drive pulley 60, if it is left as it is, an excessive torque acts on the belt 62 of the continuously variable transmission mechanism 6 at the time of reverse starting to improve durability. It has an adverse effect. However,
In the present embodiment, the PH pressure is reduced as described above when the vehicle is moving backward, and the differential pressure between the PH pressure and the PL pressure is smaller than when the vehicle is moving forward. Therefore, the gear ratio of the continuously variable transmission mechanism 6 is larger than that when moving forward. The speed is increased, and it is possible to prevent excessive torque from acting on the belt 62. Also, the amount of decrease in PH pressure, that is, PH pressure and PL
The amount of decrease in the differential pressure from the pressure is set so that the total gear ratio of the forward / reverse switching mechanism 7 and the continuously variable transmission mechanism 6 does not become equal between forward start and reverse start. The difference in axle speed between the time and the reverse start is eliminated, and the operation feeling at the time of the reverse start is improved.

The pressure regulating valve 21 regulates the hydraulic pressure (hereinafter referred to as clutch pressure) of the starting clutch 8 by using the modulator pressure as a source pressure, and the spring 21a and the left oil chamber 21b.
The third linear solenoid valve 24, which is pressed to the closing side on the right side by the clutch pressure input to the right side and is input to the oil chamber 21c on the right side
It is pressed to the left open side by the output hydraulic pressure of. The third linear solenoid valve 24 is configured to output a hydraulic pressure according to the value of the energization current to the solenoid 24a using the modulator pressure as the original pressure, and the clutch pressure is the third linear solenoid valve 24 via the pressure regulating valve 21. The hydraulic pressure is adjusted according to the output hydraulic pressure of.

An accumulator 25 having a small volume (for example, about 0.5 cc) for preventing vibration is connected to an oil passage 24b for inputting the output hydraulic pressure of the third linear solenoid valve 24 into the oil chamber 21c of the pressure regulating valve 21. There is. Here, when judder caused by stick-slip occurs during the slip control of the starting clutch 8, the pressure regulating valve 21 vibrates due to the fluctuation of the clutch pressure input to the hydraulic pressure 21b, and the oil chamber 2 accompanying this vibration.
The oil pressure in the oil passage 24b also changes due to the volume change of 1c. However,
The hydraulic pressure fluctuation of the oil passage 24b is absorbed by the accumulator 25, so that the hydraulic pressure fluctuation is not transmitted to the third linear solenoid valve 24, and the problem that the third linear solenoid valve 24 receives the hydraulic pressure fluctuation and vibrates does not occur. Since the accumulator 25 has a small volume, the response of the clutch pressure control by the third linear solenoid valve 24 does not deteriorate.

Further, in the above embodiment, the accumulator 25 is configured to have a single back pressure spring 25a. However, the back pressure spring is configured by a plurality of stages of springs to prevent judder in different hydraulic regions. It is also possible to correspond.

[0018]

As is apparent from the above description, according to the present invention, the linear solenoid valve for controlling the hydraulic pressure of the hydraulic coupling element via the pressure regulating valve causes wear of the friction material of the hydraulic coupling element and oil of the transmission. It is possible to suppress vibration due to the occurrence of judder due to stick-slip due to deterioration, etc., and to prevent the drivability from deteriorating due to deterioration of the characteristics of the linear solenoid valve.

[Brief description of drawings]

FIG. 1 is a skeleton diagram of an example of an automatic transmission to which the device of the present invention is applied.

FIG. 2 is a hydraulic circuit diagram showing a hydraulic control device for the automatic transmission of FIG.

FIG. 3 is a graph showing a hydraulic output characteristic of a linear solenoid valve.

[Explanation of symbols]

2 Automatic transmission 8 Starting clutch (hydraulic coupling element) 21 Pressure regulating valve 24 Linear solenoid valve 25 Accumulator

Front page continuation (72) Inventor Tomoyuki Kanda 1-4-1 Chuo, Wako-shi, Saitama, Ltd. Honda R & D Co., Ltd. (72) Yoshimichi Tsubata 1-4-1 Chuo, Wako-shi, Saitama Honda Engineering Co., Ltd. In the laboratory (56) Reference JP-A-10-252850 (JP, A) JP-A-3-9165 (JP, A) JP-A-11-93987 (JP, A) JP-A-11-166614 (JP, A) ) (58) Fields investigated (Int.Cl. ⁷ , DB name) F16H 59/00-63/48 F16D 48/02

Claims (3)

(57) [Claims] 1. A hydraulic pressure supplied to a hydraulic coupling element provided in an automatic transmission is controlled by a relationship between a conduction current value and an output hydraulic pressure.
In a hydraulic control device for an automatic transmission that regulates pressure with a pressure regulating valve that is controlled by a linear solenoid valve of a type that controls the vibration of the linear solenoid valve in the oil passage that inputs the output hydraulic pressure of the linear solenoid valve to the pressure regulating valve. An automatic transmission hydraulic control device characterized in that an accumulator is connected. 2. An accumulator is a volume of an oil chamber of a pressure regulating valve.
Set to a small volume that can absorb fluctuations in hydraulic pressure
The automatic transmission according to claim 1, characterized in that
Hydraulic control device. 3. A back pressure spring for the accumulator
The spring according to claim 1, wherein the spring is composed of several stages.
Hydraulic control device for automatic transmission.