JPS60260751A - Hydraulic control device of automatic speed change gear - Google Patents

Abstract

PURPOSE:To restrain a speed change shock and to quickly step on an engine brake by closing a by-pass oil path and a discharge oil path by means of a control valve in D-range and opening the above oil paths in a shift range from D- range to a low speed range. CONSTITUTION:In case of D (drive) range, as the control pressure at a control port 40 is zero, a spool 38 is pressed to the control port 40 by a spring 42 to close a by-pass oil path 26 and a discharge oil path 28. Accordingly, oil is conducted to a low clutch 10 only through an oil path 14, and oil is discharged to a high clutch 12 only through an oil path, so that a speed change shock at the time of kick-down and power-on is restrained and a speed change time is lengthened. On the other hand, in case of a shift range from D-range to a low speed range, the by-pass oil path 26 and a discharge oil path 28 are opened. Thus, speed change is quickly accomplished, and an engine brake can be stepped on immediately.

Description

[Detailed description of the invention] Technical field The present invention relates to a hydraulic control device for an automatic transmission.

BACKGROUND OF THE INVENTION In order to improve the performance of prior art automobiles, automatic transmissions include an auxiliary transmission having a low gear and a high gear. In hydraulic control for switching from a high-speed friction engagement device to a low-speed friction engagement device in an auxiliary transmission,
The friction for low gears is designed to reduce the impact of shifting during kickdown and power-on (when the driver turns on the power switch to increase engine output) in the D (driver (2) Eve) range. Supply of hydraulic medium to the engagement device and discharge of hydraulic medium from the high-speed friction engagement device are controlled. Conventional hydraulic control systems require engine braking to operate from range 2 (second) and 1. Even when switching to a low speed range such as the (low) range, switching from a high gear to a low gear is controlled in accordance with kickdown situations, etc., which delays the application of engine braking and impairs drivability.

Japanese Patent Publication No. 46-36764 discloses an orifice control valve that controls the flow of hydraulic medium to a low-speed frictional engagement device in accordance with vehicle speed. However, this orifice control valve does not control the discharge of hydraulic medium from the high-speed friction engagement device, and also does not control the discharge of hydraulic medium from the high-speed friction engagement device, and also during downshifting from D range to low-speed range (3). It was difficult to perform flow control that differentiated between the two.

Purpose The purpose of the present invention is to provide a hydraulic control device for an automatic transmission that can suppress shift impact during kickdown and power-on in D range, and can quickly apply engine brake when shifting from D range to low speed range. It is to provide.

Structure In order to achieve this object, the hydraulic control device for an automatic transmission of the present invention includes: a friction engagement device for a low speed gear that is brought into a locking state by introducing a hydraulic medium in a low gear; a high-speed friction engagement device that is in an engaged state; a first oil path that guides the hydraulic medium of the low-speed friction engagement device; a second oil path that guides the hydraulic medium of the high-speed friction engagement device; (4) A bypass oil passage that is provided in parallel with the first oil passage and has an orifice for adjusting the flow rate, and a discharge that is branched from the second oil passage and has an orifice for adjusting the flow rate. The control valve closes the oil passage and the bypass oil passage and the discharge oil passage in the drive range, and opens the bypass oil passage and the discharge oil passage in the low speed range.

Functions and Effects In the D range, the control valve closes the bypass oil passage and the discharge oil passage, so the supply of hydraulic medium to the friction engagement device for low speed gear and the discharge of hydraulic medium from the friction engagement device for high speed gear are not possible. This is carried out in accordance with the flow rates specified in the first and second oil passages, and it is possible to suppress the shift shock during downshifting to the D range.

In the case of a shift range from D range to low speed range,
Since the control valve opens the bypass oil passage and the discharge oil passage, the hydraulic medium is guided to the low-speed friction engagement device through the bypass oil passage, and also through the discharge oil passage. Hydraulic medium is discharged from the high-speed friction engagement device. Therefore, the shift from the high speed gear to the low speed gear is performed quickly, and the engine brake can be quickly applied.

Preferably, the automatic transmission includes a main transmission and an auxiliary transmission, each of which has a plurality of gears, and the low-speed friction engagement device and the high-speed friction engagement device are frictional engagement devices of the auxiliary transmission. The anti-adhesive valve has a spool that is actuated by the anti-adhesive pressure which is high in the low speed range.

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

In FIG. 1, a roller clutch IO and a high clutch I2 are provided as a friction engagement device for a low gear and a friction engagement device for a high gear, respectively, in an auxiliary transmission of an automatic transmission having a main transmission and an auxiliary transmission. , are engaged in the low speed gear and the high speed gear, respectively.

Oil passages 14 and 16 are connected to line pressure P7 by switching valves (6) not shown. low clutch lO and high clutch 12, respectively.
Guide hair oil. The oil passage 14 is provided with an orifice 18 and a check valve 20 in parallel with each other, and the oil passage 16 is provided with an orifice 22 and a second reverse IJ valve 24 in parallel with each other. The check valve 20.24 opens to drain oil from the clutch 10.12. The bypass oil passage 26 is provided in parallel to the oil passage 14 and connects both sides of the orifice +8.

The discharge oil passage 28 branches from the high clutch 12 side of the orifice 22 and reaches a drain 30. Orifice 32
．． 34 are the bypass oil passage 26 and the discharge oil passage 2, respectively.
8 and regulates the flow rate.

The orifice control valve 36 as a control valve has a spool 38 that opens and closes the bypass oil passage 26 and the discharge oil passage 28 depending on the position in the axial direction, and the spool 38 controls the control pressure of the control boat 40 and the acting force of the spring 42. The position is controlled in relation to the The space in which the spring 42 is placed is connected to the drain 44 (7), and the control pressure of the control boat 40 is sent from a manual valve, and is zero in the case of the D range. High pressure occurs in low speed ranges such as L.

Figure 2 shows the servo oil pressure P c of the low clutch 10 and high clutch 12 when switching from high speed to low speed.
It shows the change in l + P c h. The solid line is the characteristic for the D range, and the broken line is the characteristic for the 2. This is the characteristic for the L range. The operation of the orifice control valve 36 will be explained with reference to FIG.

In the case of the D range, the control pressure of the control boat 40 is zero, so the spool 38 is pressed toward the control boat 40 by the spring 42, and the bypass oil passage 26 and the discharge oil passage 28 are closed. Therefore, oil to the low clutch 10 is led only through the oil passage 14, and oil from the high clutch 12 is discharged only through the oil passage 16. As a result,
The servo oil pressures Pcl and Pch change as shown by the solid lines in FIG. 2, and changes during kickdown and power-on (8-speed impact are suppressed, and the shift time T1 becomes longer).

In the case of a shift range from the D range to a low speed range such as the 2 and L ranges, the control pressure of the control boat 4θ is high.

As a result, the spool 38 moves against the spring 42, and the bypass oil passage 26 and the discharge oil passage 28 are opened. Therefore, oil is supplied to the low clutch 10 also through the bypass oil passage 26, and oil from the high clutch 12 is also discharged through the discharge oil passage 28, so that the servo oil pressure Pc7! +Pch changes rapidly, and the opening T2 during gear shifting becomes shorter. As a result, the gears are changed quickly, and the engine brake can be applied immediately after the shift range.

Although the embodiment has been described with respect to a low clutch and a high clutch of an auxiliary transmission, the present invention can also be applied to a friction engagement device for a low speed gear and a high speed gear of a main transmission.

[Brief explanation of the drawing]

(9) FIG. 1 is a configuration diagram of an embodiment of the present invention, and FIG. 2 is a diagram showing changes in oil pressure when switching from a high speed gear to a low gear. 10...Low clutch, +2...High clutch, 1
4.16...Oil passage, 26...Bypass oil passage, 28.
...Drainage oil path, 32.34...Orifice, 36...
- Orifice control valve. (10)

Claims (1)

[Scope of Claims] l A low-speed friction engagement device that enters a locked state when a hydraulic medium is introduced in a low-speed speed; A friction engagement device for a high-speed speed that enters a locked state when a hydraulic medium is introduced in a high speed. , a first oil passage for guiding the hydraulic medium of the frictional engagement device for the low speed gear, a second oil passage for guiding the hydraulic medium of the frictional engagement device for the high speed gear, provided in parallel with the first oil passage, and A bypass oil passage that has an orifice for adjusting the flow rate, a discharge oil passage that branches from the second oil passage and has an orifice for adjusting the flow rate, and the bypass oil passage and the discharge oil passage are closed in the drive range. A hydraulic control device for an automatic transmission (1), comprising: a control valve that opens a bypass oil passage and a discharge oil passage in a low speed range. 2. The automatic transmission includes a main transmission and an auxiliary transmission, each of which has a plurality of gears, and the low-speed friction engagement device and the high-speed friction engagement device are friction engagement devices of the auxiliary transmission. A hydraulic control device according to claim 1, characterized in that: 3. The hydraulic control device according to claim 1 or 2, wherein the control valve has a spool that is actuated by a control pressure that is high in a low speed range.