JPS6388356A - Hydraulic control circuit for automatic speed change gear - Google Patents

Abstract

PURPOSE:To make it possible to form both a fail-safe circuit and a manual L inhibitor circuit together by additively providing a shift valve with an auxiliary valve to change over the shift valve in a L range by opening or closing a solenoid valve in a direction opposite to that in a D range. CONSTITUTION:The output port 20d of an auxiliary valve 20 is connected to the input port 10a of a shift valve 10, and the output port 20d of the auxiliary valve 20 to the input port 10c of an oil chamber 10C, and the input port 20a and output port 20d of the auxiliary valve 20 are connected to positions before and behind an orifice 40 respectively, and when the shift valve 10 is in a L range, it is changed over in a direction opposite to that in a D range by opening or closing a solenoid valve 4. Said one solenoid valve 4 can therefore produce four speed change stages to form both a fail-safe circuit and a manual L inhibitor circuit together.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a hydraulic control circuit for a two-forward automatic transmission having a fail-safe circuit and a manual L inhibitor circuit.

(Prior Art) Fig. 5 shows a hydraulic control circuit of a conventional automatic transmission with two forward speeds, in which 1 is a torque converter, 2 is a manual valve, and 3 is a shift valve.

4 is a solenoid valve for controlling the shift valve 3, 5 is a regulator valve, 6 is an accumulator, 7 is an oil pump, and 8 is an oil cooler. Further, the engagement of the clutch C1 and the brakes B1 and B2 at each gear stage of this automatic transmission is as shown in Table 1 below.

Table 1 (Problems to be Solved by the Invention) In this hydraulic control circuit, when shifting from the 2nd speed state of the D range to the D range, the solenoid valve 4 is kept open until the vehicle speed falls below a predetermined vehicle speed. As shown in Table 2 below, by maintaining the 2nd speed state, two manual hinge crack circuits were established, making it possible to prevent engine overrun during a manual L shift.

Table 2 However, in this conventional hydraulic control circuit, since there is only one solenoid valve for control, it is not possible to establish a fail-safe circuit in the event that the solenoid valve 4 fails.

In addition, if the hydraulic control circuit is configured as shown in Figure 6, and a fail-safe circuit is established with one solenoid valve as shown in Table 3 below, then two manual hydraulic control circuits are required. could not be established.

Table 3 This invention consists of 1. This was done in order to eliminate the drawbacks of the conventional hydraulic control circuit as described above, and it is possible to establish both a fail-safe circuit and two manual hinge circuits with one solenoid valve. The purpose of the present invention is to provide a hydraulic control circuit for an automatic transmission.

(Means for Solving the Problems) In order to achieve the above object, the present invention provides a hydraulic control circuit for a two-speed forward automatic transmission in which shift valves are switched using one solenoid valve.

The shift valve is characterized by an auxiliary valve that is operated by the manual L signal pressure in the L range and switches the shift valve in the opposite direction to that in the D range by opening and closing a solenoid valve.

(Function) In the D range, the hydraulic control circuit of the automatic transmission according to the present invention switches the shift valve to the first speed state (D-1) in response to the opening and closing of the solenoid valve.
and 2nd speed state (D-2) is established, and in the L range, the auxiliary valve is in the manifold position. The shift valve is activated by the manual L signal pressure from the Al valve, and switches the shift valve in the opposite direction to the D range in response to the opening and closing of the solenoid valve. ) is established, and 4 with - solenoid valves.
It is possible to establish the following gears (D-1, D-2, L-1, L-2).

Therefore, even if the hydraulic control circuit is an automatic transmission with two forward speeds and has only one solenoid valve.

It is now possible to establish both a fail-safe circuit and two manual failure circuits, which conventionally only allowed one of them to be established.1For example, as shown in Table 4, when the auxiliary valve is in the L range, the solenoid When the valve is closed, hydraulic pressure is conducted to the shift valve to maintain the shift valve in the 2nd speed state, and when the solenoid valve is open, the hydraulic pressure that was maintaining the shift valve in the 2nd speed condition is conducted to the discharge side. If the shift valve is configured to be in the 1st speed state, there will be a fail-safe circuit when the solenoid valve fails and it becomes open, and a manual hi-hi crack 2 circuit when the D-2 range is shifted to the D-2 range. Established together.

Table 4 (Examples) This invention will be described in more detail below based on examples shown in two drawings.

In Figs. 1 to 4, the shift valve lO is the land Il.
a, the spool 11 on which the llb is formed, and this spool I [is the spring 12 installed inside the left end side of the drawing.
is biased toward the right in the drawing. This shift valve 10 has an input port log communicating with an oil chamber 10A formed on the left end side in the drawing of land LlH of the spool 11,
Oil chamber 10 formed between land lLa and land llb
A clutch pressure output port L (lb) communicating with B, a human-powered boat lOc communicating with an oil chamber 10c formed on the right end side of the spool 11 in the drawing, and a clutch pressure output port 10c formed between this input port 10c and the clutch pressure output port 10b. human power port lo
d. And spool 11 is spring 1
When the clutch pressure output port 10b is biased to the right position in the drawings (Figs. 1 and 3), the clutch pressure output port 10b communicates with the input port lod via the oil chamber 10B, and the spool 11 resists the spring 12 and is positioned at the right position in the drawings (Figs. 1 and 3). When placed in the left position (Figures 2 and 4)
The input port 10d is closed by a land fob, and the clutch pressure output port 10b is communicated with the drain boat 10e.

The inhibitor valve 20 (auxiliary valve) has a land 21a,
The spool 21 has a spool 21 having a spool 21b formed therein, and this spool 2I is biased toward the left in the drawing by a spring 22 installed inside the left end side in the drawing. This inhibitor valve 20 is connected to a human-powered boat 20 that communicates with an oil chamber 20A formed between a land 21a and a land 21b of a spool 21.
a, an output port 20b formed on the left side of this manual port 20a in the drawing, a manual L signal pressure input port 20c communicating with the oil chamber 2OB formed on the right end side of the spool 21 in the drawing, and this manual L signal pressure input port 20c
Output port 1-2 formed between the and the human power port 20a
0d. When the spool 21 is biased by the spring 22 and positioned at the right position in the drawing (first and second
Figure) The input port 20a is connected to the output port 20d with an oil chamber 20A.
The output port 20b is communicated with the drain port 20e, and the spool 2
1 is positioned at the right position in the drawing against the spring 22 (Figs. 3 and 4), the output port 20d is connected to the land 21b.
Instead, the manual port 20a is communicated with the output port 20b.

The input port loa of the shift valve 10 communicates with the output port 20d of the inhibitor valve 20, and the input port 10d
communicates with the upstream side of the orifice 40 of the line pressure oil passage L1, and the input boat 10C of the oil chamber 10C communicates with the 4-stream side of the orifice 40 of the line pressure oil passage Ll via the orifice 50, and also communicates with the upstream side of the orifice 40 of the line pressure oil passage L1. It communicates with the output port 20d.

The input port 20a of the inhibitor valve 20 is in communication with the downstream side of the orifice 40 of the line pressure oil passage L1.
Further, the input port 20c of the oil chamber 20B is communicated with the manual L signal pressure output port 30a of the manual valve 30.

The configuration of other parts of the hydraulic control circuit and the operation of the clutch and brake at each gear stage are the same as the conventional hydraulic control circuit shown in FIG.

Next, the operation of the hydraulic control circuit at each gear stage will be explained in order based on the corresponding figures.

Figure 1 shows the 2nd speed state (D-2) of the D range.
Solenoid valve 4 is open.

Therefore, the line pressure from the manual valve 30 in the oil passage L1 does not generate pressure in the manual port lOc of the shift valve 10, and since it is in the D range, the manual L signal pressure input port 20C is in the oil chamber 2OB of the inhibitor valve 20. L signal pressure is not generated from spool 2.
1 is biased by a spring 22 and positioned at the right position in the drawing, and the input port 20a and the output port 20d are communicated via the oil chamber 20A, so that the shift valve I
No pressure is generated in the oil chamber C of O.

Therefore, the spool 11 of the shift valve 10 is biased by the spring 12 and positioned at the right position in the drawing, and the input port 1
0d and the clutch pressure output port IOb are communicated, line pressure from the oil passage L1 is introduced into the clutch C1, and the second speed state is established as shown in Table 1 above.

Figure 2 shows the 1st speed state (D-1) of the D range.
When the vehicle speed is reduced from the second speed state (D-2) in FIG. 1 to a predetermined vehicle speed or less, the solenoid valve 4 is closed. Therefore, the line pressure from the manual valve 30 in the oil path L1 is input to the oil chamber 10C of the shift valve IO at the input port 10C.
introduced from. In addition, since the inhibitor valve 20 is in the D range, no L signal pressure is generated, so the line pressure is from the manual boat 20a to the output port 20d to the manual port L.
The oil is introduced into the oil chamber 10c via the oc.

The spool 1 is caused by the hydraulic pressure introduced into this oil chamber 10C.
1 is moved to the left in the drawing against the spring 12, thereby the input port 10d is closed by the land 11b, and the clutch pressure output port 10b is communicated with the drain boat foe, so that the clutch pressure is discharged from the drain boat LOe. Ru.

Therefore, the clutch C1 is disengaged and the brake B1 is engaged by the line pressure from the manual valve 30 in the oil passage L2, so that the first speed state is established as shown in Table 1.

Figure 3 shows the second speed state (L-2) of the L range.
From the 2nd speed state (D-2) in Figure 1, the manual valve 30
When the vehicle is shifted to the L range, the solenoid valve 4 is closed until the vehicle speed is reduced to a predetermined vehicle speed or less. Then, the L signal pressure is output from the manual L signal pressure output port 30a of the manual valve 30, and the inhibitor valve 2
0 manual L signal pressure input boat 20C to oil chamber 2O
B and slides the spool 21 to the left in the drawing against the spring 22.

As a result, the output port 20d is closed by the land 21b, and from the oil passage L1 to the oil passage L via the orifice 50.
The hydraulic pressure introduced into the boat 20d is cut off by the boat 20d. Furthermore, by communicating the input port 20a and the output port 20b, line pressure is introduced from the oil passage L1 into the oil chamber 1OA via the manual port 20a, the oil chamber 20A, the output port 20b, and the input boat lOa of the shift valve 10. Ru.

Therefore, there is an orifice 5 in the oil chamber 10C of the shift valve 10.
Even though line pressure is introduced into the oil chamber 10C through the oil chamber 10A, the spool 11 is biased by the spring 12 and the hydraulic pressure introduced into the oil chamber 10A, and is positioned at the right position in the drawing. The input port IOd and the clutch pressure output port (fob) are communicated with each other, and the oil passage L is connected to the clutch C1.
2nd speed state is maintained by introducing clutch pressure from 1st gear.

As described above, when shifting from the D-2 state to the L range, the solenoid valve 4 is closed until the vehicle speed is decelerated below a predetermined speed, and the shift valve 10 is maintained in the 2nd speed state by the operation of the inhibitor valve 20. A manual L inhibitor circuit is established.

Figure 4 shows the 1st speed state (L-1) of the L range.
The spool 21 of the inhibitor valve 20 is held at the left position in the drawing by the L signal pressure from the manual valve 30, as in the case of FIG. Then, in the 2nd speed state (L
-2) When the vehicle speed becomes less than a predetermined vehicle speed, the solenoid valve 4 is opened.

As a result, the pressure oil from the oil chamber 10A of the shift valve 10 is discharged from the solenoid valve 4 via the boat 1oa, the boat 20b, and the boat 20a, so that the oil pressure in the oil chamber 10C overcomes the spring 12 and attaches the spool 11. Slide the drawing to the left. As a result, pressure oil is drained from the clutch C1 to the drain boat 10e as in the case shown in Fig. 2.
The brake B1 is engaged by the brake pressure from the oil passage L2, and the first speed state (L-1) is established.

Here, in the L-2 state of FIG. 3, if the solenoid valve 4 fails and becomes open.

The state shown in Fig. 4 is reached and the 1st speed state is maintained.

A fail-safe circuit will be established.

(Effects of the Invention) As mentioned above, this invention is achieved by attaching to the shift valve an auxiliary valve (inhibitor valve) that switches the shift valve in the opposite direction to that in the D range by opening and closing a solenoid valve when in the L range. In an automatic transmission with two forward speeds, it is possible to obtain four different speeds with one solenoid valve, and it is possible to establish both a fail-safe circuit and a manual L inhibitor circuit.

In order to eliminate the drawbacks of the conventional technology, it was considered to add one manual inhibitor solenoid valve in addition to the 1-2 shift solenoid valve, but in the case of a 2-speed ATM, Since the space is small and the added solenoid valve is used exclusively for the manual L inhibitor and cannot be used effectively for other circuit configurations, it is difficult to secure space, and furthermore, the cost increases because solenoid valves are expensive. However, in the present invention, only one additional small and inexpensive auxiliary valve is required, so there are no problems like those in the -1st era in terms of securing space and cost.

[Brief Description of the Drawings] Fig. 1 is a hydraulic circuit diagram showing the D-2 state in one embodiment of the present invention, Fig. 2 is a hydraulic circuit diagram showing the D-1 state in the same embodiment, and Fig. 3 is a hydraulic circuit diagram showing the D-1 state in the same embodiment. FIG. 4 is a hydraulic circuit diagram showing the L-2 state in the same embodiment, and FIG. 4 is a hydraulic circuit diagram showing the L-1 state in the same embodiment. 5 and 6 are hydraulic circuit diagrams showing a conventional example. 4... Solenoid valve, 10... Shift valve. 2G...Inhibitor valve. 20c...Manual L signal pressure input port. 30...Manual valve. 30a...Manual L signal pressure output port. CI...Clutch. Bl, B2...Brake.

Claims (1)

[Claims] 1. In a hydraulic control circuit for a two-speed forward automatic transmission in which a shift valve is switched by one solenoid valve, the shift valve is operated by a manual L signal pressure in an L range, and the shift valve is switched by opening and closing the solenoid valve. A hydraulic control circuit for an automatic transmission, characterized in that a shift valve is provided with an auxiliary valve for switching in a direction opposite to that in D range. 2. When the auxiliary valve is in the L range and the solenoid valve is closed, hydraulic pressure is conducted to the shift valve to maintain the shift valve in the 2nd speed state, and when the solenoid valve is open, the shift valve is maintained in the 2nd speed state. 2. The hydraulic control circuit for an automatic transmission according to claim 1, wherein the hydraulic pressure is conducted to the discharge side to put the shift valve in the first speed state.