JPS6388358A - Hydraulic control circuit for automatic transmission - Google Patents

Abstract

PURPOSE:To make a safe driving of an automobile possible by connecting an inhibitor valve which can be actuated by any one of solenoid valves for controlling shift valves. CONSTITUTION:An inhibitor valve 7 which can be actuated by any one of solenoid valves S1 through S3 for controlling shift valves V1 through V5 is connected to a hydraulic control circuit. Since this makes it possible to establish simultaneously both the inhibitor for making a manual driving possible at a time of wire breakage of solenoid valves S1 through S3 and the inhibitor for preventing an overrunning at a time of a manual down-shift, a safe driving of an automobile becomes possible.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a hydraulic control circuit for an automatic transmission having an inhibitor circuit.

(Prior technology) The hydraulic control circuit of conventional automatic transmissions has a so-called fail-safe function that enables manual driving even if the solenoid valve is disconnected, and a function that prevents engine overrun in the event of manual down-down at high speeds. There were some that had an inhibitor function for this purpose.

For example, a solenoid valve Sl as shown in Table 1 below.
, In an automatic transmission with four forward speeds that constitute each gear stage, if the D range is manually downgraded from 3rd or 4th gear to 2nd gear by the operation of S2, the engine will overrun if the gear is shifted to 2nd gear immediately. Solenoid valves S1 and S2 until the vehicle speed is decelerated below a predetermined value.
was held in 4th gear (inhibitor during manual down).

Table 1 ○...On ×...Off Also, in the above automatic transmission, solenoid valve S1
Or if S2 is disconnected, as shown in Table 1, D
In the range, manual shift driving is possible in 4th, 3rd, or 1st speed, and in the 2nd range, manual shift driving is possible in 1st speed, and furthermore, if both solenoid valves S1 and 82 are disconnected, It was possible to drive with manual shift in 3rd gear.

(111 problems to be solved by the invention) But what about the hydraulic side of the conventional automatic transmission? For 8 circuits.

In order to ensure a fail-safe in the event of a solenoid valve disconnection, there were some gears in which the inhibitor could not be secured.

For example, in an automatic transmission that operates as shown in Table 1 above, it was possible to establish an inhibitor between 4th and 2nd speeds or between 3rd and 2nd speeds, but between 4th and 3rd speeds. An inhibitor in between could not be established.

As mentioned above, this is the solenoid valve S in the 2nd range.
1, S2 is disconnected, a fail-safe is ensured so that manual shift driving is possible in 3rd gear, and D range 4th gear and valve S1. This is because the 2nd range and 3rd speed are in the same state when both S2 are disconnected, so when the 4th speed of the D range is manually downgraded to the 2nd range, the 3rd speed is automatically set.

Therefore, with conventional automatic transmissions, there was a risk that the engine would overrun if the vehicle was manually switched down at high vehicle speeds.

This invention was made in order to eliminate the drawbacks of conventional automatic transmissions as described above, and is an automatic transmission that enables safe driving by having both an inhibitor circuit and a fail-safe circuit in high speed gears. The purpose of this invention is to provide a hydraulic control circuit for a transmission.

(Means for Solving the Problems) In order to achieve the above object, the present invention provides a first solenoid connected to a spool control line pressure oil passage of each of the 1-2 shift valve and the 3-4 shift valve. a second solenoid valve connected to the spool control line pressure oil passage of the 4-5 shift valve; and a third solenoid valve connected to the spool control line pressure oil passage of at least the 2-3 shift valve. The hydraulic control circuit that establishes each gear by combining the on and off of these solenoid valves can be operated by either solenoid valve, and has an inhibitor in the event of a solenoid valve disconnection and an inhibitor in the manual downshift. This feature is characterized by the connection of an inhibitor valve that can achieve both of these effects.

(Function) In the hydraulic control circuit according to the present invention, the connection of each spool control line pressure to the 1-2 shift valve and the 3-4 shift valve is controlled by turning on and off the first solenoid valve, and the 4-5 shift valve is controlled by turning on and off the first solenoid valve. The connection of the spool control line pressure to the shift valve is controlled by turning on and off the second solenoid valve, and the connection of each spool control line pressure to at least 2-3 shift valves is controlled by turning the third solenoid valve on and off.・It is controlled by turning off the solenoid valve, which controls two shift valves at the same time.By combining the on and off states of the solenoid valve, the friction material is selectively engaged to establish each gear stage of the automatic transmission. Furthermore, at each gear stage, an inhibitor valve connected to the hydraulic control circuit establishes an inhibitor when the solenoid valve is disconnected to enable manual shift driving, and at the same time, establishes an inhibitor at the time of manual downshift. Prevent engine overrun.

(Example) The present invention will be described in more detail below based on an example shown in one drawing.

FIG. 1 is a hydraulic control circuit diagram showing an embodiment of the present invention in an automatic transmission with six forward speeds, and FIG. 2 shows a gear train of the automatic transmission controlled by the hydraulic g11 circuit in FIG. It is something that

First of all, to explain the configuration of the hydraulic control circuit in Fig. 1, 1 is the torque converter, 2 is the manual valve, 3 is the primary regulator valve, 4 is the secondary regulator valve, 5 is the throttle valve, and 6 is the lock-up control. valve, 7 is an inhibitor valve,
8 is the oil pump, Vl is the 1-2 shift valve, V2 is the 2-3 shift valve, V3 is the 3-4 shift valve, V4
is 4-5 shift valve, V5 is 5-6 shift valve, S
1-S3 is a solenoid valve, and S4 is a duty solenoid valve for lock-up control.

The solenoid valve Sl (first solenoid valve) is a normally closed type solenoid valve, and is an oil passage that communicates the line pressure oil passage L1 from the oil pump 8 with the spool control oil chamber Via of the 1-2 shift valve v1. L
Connected to 2. Also, the oil chamber V of the 1-2 shift valve
ia communicates with the spool control oil chamber V3a of the 3-4 shift valve V3.

The solenoid valve S2 (second solenoid valve) is a normally open type solenoid valve that communicates oil between the line pressure oil passage L1 and the spool control oil chamber V4a of the 4-5 shift valve v4 via the inhibitor valve 7. It is connected to road L3.

Further, the solenoid valve S3 (third solenoid valve) is a normal oven type solenoid valve,
It is connected to oil passages L4 and L5 that communicate the line pressure oil passage L1 with the spool control oil chamber V2a of the 2-3 shift valve V2 or the spool control oil chamber V5a of the 5-6 shift valve V5, respectively. Solenoid valves S1 to S3 and shift valves v1 to
The operation of V5 at each gear position and the operation of clutches 01 to C3 and brakes 81 to B3 of the gear train shown in FIG. 2 at each gear position are as shown in Table 2 below.

In Table 2, that is, in the reverse state (Rev), all solenoid valves 81 to S3 are off, so only solenoid valve S1 is closed, and 1-2 shift valve v1
Oil chamber Via and oil chamber V3 of 3-4 shift valve V3
Pressure oil is introduced into a from the line pressure oil passage Ll, and each spool is slid downward in the drawing, and the spools of the other shift valves are positioned in the direction shown in the drawing.

Therefore, the line pressure is conducted from the line pressure oil passage L1 to the B3 oil passage LB3 via the 1-2 shift valve v1, and the R range pressure from the manual valve 2 (oil passage L8) is 1-2.
It is connected to the C2 oil passage LC2 via the shift valve V1,
Clutch C2 and brake B3 are engaged and the Rev state is established.

In the neutral state (N), the solenoid valves 81 to S3 are turned off and the shift valves V1 to V5 are in the same state as in the Rev state, but only the brake B3 is engaged because R range pressure is not generated. Then, the N state is established.

In the first speed state (1st), only the solenoid valve S3 is on, and therefore the solenoid valve Sl.

B3 is closed, and line pressure is introduced into the oil chamber V2a of the 2-3 shift valve ■2 via the solenoid valve S3. The spool is positioned at the bottom of the drawing.

Therefore, in addition to engaging brake B3, D range pressure (or 3 range pressure, 2 range pressure,
Lunge pressure (generally referred to as D range pressure) is oil passage L7 -
2-3 Shift Valve V2- Oil Path L8- 4-5 Shift Valve ■4- Conducted to C1 Oil Path LCI via Oil Path L9, Clutch C1 is engaged, and the 1st state is established.

Note that when the solenoid valve S3 is turned on, pressure oil is introduced into the oil chamber V5a of the 5-6 shift valve V5, but the spool is biased by the D range pressure from the oil passage L9 and the spring to the -1 position in the drawing. Retained.

In the 2nd speed state (2nd), solenoid valves S1 and B3 are turned on, and only solenoid valve S3 is closed.
1-2 shift valve v1 and 3 by 1 oven
-4 The spools of the shift valve v3 are each slid by a spring and positioned at a position on the drawing.

Therefore, the line pressure to the brake B3 is cut by the 1-2 shift valve v1, and the D range pressure (oil path L7) is changed to the 1-2 shift valve v1-oil path L9-2.
-3 Shift valve V2 -Oil path LIO-3-4 Shift valve V3-Oil path Lll -5-6 Conducted to B2 oil path LB2 via shift valve v5, and the 2nd state is set by engagement of clutch C1 and brake B2. To establish.

When in 3rd gear fi (3rd), solenoid valve S1
Only solenoid valve S3 is turned on, all solenoid valves become ovens, and 2-3 shift valve v2 is slid to the position shown in the drawing by the oven of solenoid valve S3 for the 2nd state.

Therefore, the 2-3 shift valve v2 switches the D range pressure from the oil path L9 from the oil path LIO to the oil path L12 and brakes B.
The D range pressure to 2 is cut, and this D range pressure is transferred to oil path L12 - 3-4 shift valve v3 - oil path L13 - 4-5 shift valve V4 - oil path L14.
- 5-6 It is conducted to the B1 oil passage via the shift valve V5, and the third state is established by engaging the clutch C1 and the brake B1.

In the 4th speed state (4th), all the solenoid valves are turned off, so only the solenoid valve S1 is closed, and the 3-4 shift valve V3 is closed in the 3rd state.
is slid downward in the drawing. By closing the solenoid valve S1, line pressure is also introduced into the oil chamber Vla of the 1-2 shift valve V1, but the D range pressure introduced from the oil passage L15 via the 2-3 shift valve V2 is applied to the spool along with the spring. Because it biases upward.

The spool of the 1-2 shift valve V1 is still held in the position shown in the drawing.

Therefore, the D range pressure from the oil path L12 is switched from the oil path L13 by the 3-4 shift valve V3, and the 03 oil path L
Conductive to C3 and cut to brake B1, and the 4th state is established by engagement of clutches C1 and C3.

In the 5th speed state (5th), only solenoid valve S2 is turned on, so solenoid valves S1 and B2 are turned on.
is closed, line pressure is introduced into the oil chamber V4a of the 4-5 shift valve V4 via the inhibitor valve 7,
The spool is slid toward the 4th state in the drawing direction.

Therefore, from oil path L8 to C by 4-5 shift valve ■4.
The continuity of the D range pressure to the first oil passage LC1 is cut and the first oil passage L12-oil passage L1B-3-4 shift valve v
3- The D range pressure that was conducted to oil path L17 is 4-
5 shift valve v4- Oil passage L14-5-6 Connected to Bl oil passage LBI via shift valve v5, and clutch C
3 and the engagement of brake B1 establishes the 5th state.

In the 6th speed state (6th), solenoid valves B2 and B3 are turned on, so all solenoid valves are closed, and line pressure is introduced into the oil chamber V5a of the 5-6 shift valve V5 by closing the solenoid valve S3. The spool is slid to the lower position in the drawing for the 5th state. Note that by closing the solenoid valve S3, line pressure is also introduced into the oil chamber V2a of the 2-3 shift valve V2, but the line pressure is also introduced into the oil chamber V2a of the 2-3 shift valve V2. The pressure, together with the spring, urges the spool of the 2-3 shift valve V2 upward, so that the spool is still held in the drawing position.

Therefore, the 5-6 shift valve v5 cuts off the continuity of the D range pressure from the oil path L14 to the B1 oil path and Bl.
Instead, D range pressure is conducted from C3 oil path LC3 to B2 oil path LB2 via oil path L20-4-5 shift valve ■4- oil path L21-5-6 shift valve V5,
6th by engagement of clutch C3 and brake B2
A state is established.

Although the above hydraulic control circuit is for 6 forward speeds, the 75-6 shift valve 5 is removed and the oil passages L14 and LB1. By connecting the oil passage Lll to the oil passage LB2 and the oil passage L20 to the oil passage L21, a hydraulic control circuit for five forward speeds can be constructed by operating the solenoid valves similar to those in the above embodiment.

In the above embodiment, the solenoid valve S1 is a normally closed type, and the solenoid valves S2 and B3 are of the normally closed type.
Although the solenoid valves are assumed to be normally open types, the types of each solenoid valve are not limited to these.

Here, the oil chamber 7a of the inhibitor valve 7 is connected to the line pressure oil passage Ll via the solenoid valve S2, and the oil chamber 7a is further connected to the oil chamber V4a of the 4-5 lift valve V4 through an oil passage L3. There is. And this inhibitor valve 7.

The oil passage L18 and the oil passage L22 are always communicated to conduct the three range pressure from the manual valve 2 to the oil chamber 4Vb of the 4-5 shift valve 4V.

Furthermore, when the line pressure is not conducted to the oil chamber 7a, the inhibitor valve 7 connects the oil path L1g to the oil path L23.
The 3-range pressure is communicated to the oil chamber V3b of the 3-4 shift valve ■3, and the oil passage L2
4 and an oil passage L25 to communicate the 2-range pressure to the oil chamber V2b of the 2-3 shift valve 2V.

Solenoid valve SL, S in manual 3 range
2. Operation of S3 and associated shift valves v1 to v5
The engagement of the clutch and brake is the same as in the 3rd state described above, with solenoid valve S1 on, solenoid valve S2. B3 is off, that is, all solenoid valves are open.

Here, even if all the solenoid valves are disconnected, that is, even if the solenoid valve S1 is turned off and closed, the oil path L7-2-3 shift valve V2-
Oil chamber Vl of 1-2 shift valve v1 via oil passage L15
Since the D range pressure is introduced from the manual valve 2 to b, the spool of the 1-2 shift valve v1 is held in the upper position, and the oil chamber V3b of the 3-4 shift valve V3 is
Oil passage L18 - Inhibitor valve 7 - Oil passage L
Since the 3-range pressure is introduced from the manual valve 2 through 23, the spool of the 3-4 shift valve V3 is maintained at the upper position.

Therefore, even if the solenoid valve is disconnected, the orientation of each shift valve does not change, so the 3rd state is maintained, and an inhibitor is established when the solenoid is disconnected.

Also, when manual downshifting of D-3 is performed while driving at high speed in 4th gear, if the solenoid valve S1 is controlled from on to off and the solenoid valve S2 is controlled from off to on, a line is connected to the oil chamber 7a of the inhibitor valve 7. pressure is introduced, the spool is slid to the lower position in the drawing, and the 3 range pressure from the oil passage L1g to the 3-4 shift valve v3 is cut, so the spool of the 3-4 shift valve V3
The key is slid to the bottom position in the drawing and the 4th state is maintained.

Therefore, when a manual downshift from D to 3 is performed while driving at high speed, solenoid valve Sl.

If S2 is controlled as described above, the 4th state is maintained and an inhibitor at the time of manual down is established.

Conventionally, the hydraulic pressure of the manual 3 range was directly connected to the 3-
Because it was introduced into the oil chamber V3b of the 4-shift valve V3,
3rd for strong 1 purpose during manual shift down of D-3
I ended up downshifting.

The inhibitor was established when the solenoid was disconnected, but the inhibitor was not established when the solenoid was down manually.

(Effects of the Invention) As described above, the present invention connects an inhibitor valve that can be actuated by any solenoid valve for shift valve control to a hydraulic control circuit, thereby preventing manual override in the event of a solenoid valve disconnection. It is possible to achieve both an inhibitor for enabling shift driving and an inhibitor for preventing engine overrun during manual downshifting, thereby enabling safe driving of the automobile.

[Brief explanation of the drawing]

Fig. 1 is a hydraulic control circuit diagram showing one embodiment of the present invention;
This figure is a skeleton diagram showing a gear train of an automatic transmission operated by the hydraulic control circuit of FIG. 1. 2...Manual valve. 7...Inhibitor valve. vl...1-2 shift valve. v2...2-3 shift valve. v3...3-4 shift valve. v4...4-5 shift valve. v5...5-6 shift valve. Sl, S2. S3... Solenoid valve. C1, C2, C3...Clutch. Bl, B2. B3...Brake.

Claims (1)

[Claims] The first line connected to the spool control line pressure oil passage of each of the 1-2 shift valve and 3-4 shift valve
a solenoid valve, a second solenoid valve connected to the spool control line pressure oil passage of the 4-5 shift valve, and a third solenoid valve connected to the spool control line pressure oil passage of at least the 2-3 shift valve; It is equipped with a hydraulic control circuit that establishes each gear stage by combining the on and off of these solenoid valves, and can be operated by either solenoid valve, and has an inhibitor in the event of a solenoid valve disconnection and an inhibitor in the event of a manual downshift. 1. A hydraulic control circuit for an automatic transmission, characterized in that an inhibitor valve is connected that can also establish an inhibitor.