JPH0285567A - Hydraulic control device for automatic transmission - Google Patents

Abstract

PURPOSE:To simplify a hydraulic circuit by selectively driving a single shift valve capable of switching first-fourth speed change stages and two solenoid valves generating the signal oil pressure to operate it. CONSTITUTION:A shift valve 14 has the first and second spools 30 and 31 arranged in series, the signal oil pressure PS1 of the first solenoid valve 15 is guided to the middle position of both spools, and the signal oil pressure PS2 of the second solenoid valve 16 is guided to the end section of the second spool 31. The first operation position (first speed) that both spools are located at one end side in the contact state is obtained when both solenoid valves 15 and 16 generate no signal oil pressure, the second operation position (second speed) that both spools are located at the middle section in the contact state is obtained when only the second solenoid valve 16 generates the signal oil pressure, the third operation position (third speed) that both spools are located at the other end side in the separated state is obtained when both solenoid valves generate the signal oil pressure, and the fourth operation position (fourth speed) that both spools are located at both ends in the separated state is obtained when only the first solenoid valve 15 generates the signal oil pressure.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a hydraulic control device for an automatic transmission, and more particularly to a hydraulic control device for an automatic transmission having four forward gear speeds.

[Conventional technology]

Conventionally, in the case of an automatic transmission having a fourth forward gear, at least three shift valves are required to switch between the first to fourth gears by supplying or discharging hydraulic pressure to a friction element. That is, they are a 1-2 shift valve, a 2-3 shift valve, and a 3-4 shift valve. Then, signal hydraulic pressure from a governor valve, throttle valve, etc. is guided to these shift valves, and the gear stage is switched according to control factors such as vehicle speed and throttle opening.

[Problem to be solved by the invention]

However, when changing gears using three shift valves as described above, hydraulic pressure is supplied to the friction elements via multiple valves, resulting in a delay in the rise of hydraulic pressure and , the hydraulic circuit becomes more complex,
Confidence tends to decline.

In addition, when changing gears using the signal oil pressure from the governor valve or throttle valve as described above, the degree of freedom in control is small and variations are likely to occur due to changes in oil temperature. Some proposals have been made to switch between the three shift valves, but at least two solenoid valves are required to operate the three shift valves, and the signal hydraulic pressure from these solenoid valves is guided to each of the two shift valves. There is a need. However, the output oil amount of the solenoid valve at -a is small, and when that oil amount is distributed to the two shift valves, there is a corresponding delay in the rise of the signal oil pressure, which also causes a delay in the operation of the shift valves, resulting in a delay in gear shifting operation. The problem is that it becomes slow.

The present invention has been made in view of the above-mentioned problems.The purpose of the present invention is to simplify the hydraulic circuit by switching between 1st to 4th gears with a single shift valve, and to eliminate delays in shift operation. An object of the present invention is to provide a hydraulic control device for a transmission.

[Means to solve the problem]

In order to achieve the above object, the hydraulic control device for an automatic transmission of the present invention includes a single shift valve capable of switching between 1st to 4th gears by supplying or discharging hydraulic pressure to a friction element; and two electromagnetic valves that generate signal oil pressure for operating the valves, the shift valve has a first spool and a second spool arranged in series, and the signal oil pressure of the first electromagnetic valve is applied to the first spool. The signal hydraulic pressure of the second solenoid valve is guided to an intermediate position between the spool and the second spool, and the signal hydraulic pressure of the second solenoid valve is guided to the end of the second spool. A first operating position where the second spool is in contact with one end, and a second operating position where the second spool is in contact with the first and second spools when only the second solenoid valve generates signal oil pressure. and when both solenoid valves generate signal hydraulic pressure, the first. The third operating position is where the second spool is in a separated state and is on the other end side, and the first spool is in the third operating position when only the first tffi valve generates a signal hydraulic pressure. The second spool is characterized in that the second spool has a fourth operating position at both ends in a spaced apart state.

[Effect]

That is, the shift valve is composed of two spools arranged in series, and four operating positions are realized by guiding signal hydraulic pressure from two magnetic valves to the shift valve. If the first operating position is 1st gear, the second operating position is 2nd gear, the third operating position is 3rd gear, and the fourth operating position is 4th gear, a single shift valve can be used to shift from l to 4th gear. All gears can be changed. Therefore, the hydraulic circuit is extremely simplified, and the hydraulic pressure rise of the friction element is quick. In addition, since the signal oil pressure of each solenoid valve only needs to be supplied to one location, a delay in the rise of the signal oil pressure can be eliminated, and a speedy shift operation can be realized.

〔Example〕

FIG. 1 shows a schematic configuration of an automatic transmission having four forward speeds according to the present invention.

The power transmission mechanism of this automatic transmission includes an input shaft 2 driven by an engine via a torque converter 1, and first to
A third clutch C,,C,,Cyu, first and second brakes b,,Bg, a servo piston 3 that engages and releases the first brake b1, and a Ravignaux-type planetary gear mechanism 4,
It consists of a one-way clutch 40 and an output shaft 5.

A reverse sun gear 4a of the planetary gear mechanism 4 is connected to the input shaft 2 via a first crank C1, and a forward sun gear 4b is connected to the input shaft 2 via a second crank Ct. One end of the carrier 4C is connected to the intermediate shaft 6 and the third
It is connected to the input shaft 2 via the clutch C3, and the carrier 4
The other end of C is connected to a fixed member 7 such as a casing via a second brake B2 and a one-way clutch OWC. In addition, the one-way clutch OWC is carrier 4C.
Only forward rotation (direction of engine rotation) is allowed. The carrier 4c supports two types of planetary gears 4d and 4e, and the reverse sun gear 4a is a first gear that is long in the axial direction.
meshes with planetary gear 4d, forward sun gear 4
b meshes with the first planetary gear 4d via the second planetary gear 4e. A resign gear 4 which meshes only with the first planetary gear 4d is coupled to the output shaft 5.

The above power transmission mechanism realizes the gear stages shown in Table 1 by operating the clutches C, , C, □ C3, brakes b+, Bz, and one-way clutch Ot+C.

In Table 1, O indicates the operating state. In addition, B
, indicates the working side oil chamber of the servo piston 3, B, ゛ indicates the releasing side oil chamber of the servo piston 3, and both oil chambers B,...
When hydraulic pressure is introduced to B and ' (at 3rd speed), the first brake b1 is released.

Table, l Clutch C+, Ct, Ci and brake b7
, 8g, as shown in Figure 2, the hydraulic circuit includes an oil pump 10, a regulator valve 11, a manual valve 12, a throttle valve 13, and a shift valve 1.
4. First solenoid valve 15, second solenoid valve 16, second clutch control valve 17.4-3 timing pulp 18.
2-3 timing valve 19.3-2 timing pulp 20, first clutch accumulator 21, second clutch accumulator 22, third clutch accumulator 23, first brake accumulator 24, three-way valve 2
5. Consists of one-way valves 26 to 29, etc.

Among the above hydraulic circuits, the shift valve 14, the first solenoid valve 1
5. Since the components other than the second electromagnetic valve 16 and the second clutch control valve 17 are not directly related to the present invention, a detailed explanation will be omitted, and the oil pressure of each oil passage will only be listed as follows. That is, PL is line pressure, PL (R) is line pressure during reversing, P is throttle pressure, Pel is first clutch pressure, Po is second clutch pressure, PC3 is third clutch pressure, P
□ is the first brake engagement pressure, P□・ is the first brake release pressure, P□ is the second brake pressure, P! + is the first solenoid pressure, and psx is the second solenoid pressure.

The shift valve 14 is the second shift valve. These are valves that control the oil pressure of both oil chambers B, B,' of the third clutch Cx, C3 and the servo piston 3, and are two valves arranged in series so that they can move freely relative to each other as shown in Figs. 3 to 6. It is equipped with a spool 30.31 and has a total of four operating positions. The second spool 31 is thicker than the first spool 30, and the movement stroke of the second spool 31 to the left is limited by the stepped portion 32. Three types of lands 30a, 30b (31a), and 31b with different diameters are formed on the first spool 30 and the second spool 31, and the pressure receiving area of the land 30a is AI, and the pressure receiving area of the land 30b (31a) is Az. , the pressure receiving area of the land 31b is A, the pressure receiving area ratio of each land is set as follows.

AI:Ax:Ax=t:2:3
-(i) The shift valve 14 includes, from the left in FIG.
Boat 33 to which line pressure PL is input, drain boat 3
4. A boat 35 that outputs the third clutch pressure P0, a boat 36 that outputs the first brake pressure P□, a boat 37 that receives the line pressure PL, and a second clutch pressure P.

a boat 38 that outputs the same, a boat 39,40 that receives the first solenoid pressure PSI from the first solenoid valve 15, a port 41 that receives the line pressure PL, a second clutch pressure P,
2, a drain boat 43, a boat 44 that outputs the first brake release pressure P□・, a boat 45 connected to the boat 35 that outputs the third clutch pressure PC3, and the second solenoid valve 16. 2nd solenoid pressure P
! Boats 46 to which t is input are sequentially provided.

Both the first solenoid valve 15 and the second solenoid valve 16 are normally closed solenoid valves, and when the input signal is ON, the output hydraulic pressure (Psl,
Psz) becomes 0 (drain) and the input signal is OF.
When F, the output oil pressure (Psl, Psz) is line pressure PL.
becomes. The solenoid pressure P 5+ of the first solenoid valve 15 is guided to the intermediate portion between the first spool 30 and the second spool 31 as described above, and the solenoid pressure P 5+ of the second solenoid valve 16
is guided to the right end of the second spool 31. Gear stage and first solenoid pressure P! ++The relationship with the second solenoid pressure psz is as follows.

Table 2. The reason why both solenoid valves 15 and 16 are normally closed solenoid valves is that if one of the input signal systems is disconnected during high-speed driving, when the gear is shifted to 1st or 2nd gear, 2. ．． This is because the output oil pressure P is generated to automatically shift to 3rd gear (see Fig. 5) since a drastic shift is applied.

The second clutch control valve 17 is a shift valve■
2nd clutch pressure P output from boat 38.42 of No. 4
C! This is a valve for supplying the higher hydraulic pressure to the second clutch C2, and has a structure as shown in FIG. That is, the spool 51 is biased to the right by a spring 50, the bows 52 and 53 are connected to the boat 38 of the shift valve 14, and the boat 54 is connected to the soft valve 14.
The boat 55 is connected to the second clutch C
2 is connected. When the second crunch pressure PC2 is not applied manually to the right end boat 52, the boats 54 and 55 communicate with each other as shown in the upper half of FIG. As shown in the lower half of Figure 7, boats 53 and 55 communicate with each other. The reason for providing the second clutch control valve 17 is that if the boats 38 and 42 of the shift valve 14 are directly connected to the second clutch C2, the boat 42 will communicate with the drain boat 43 in 1st gear (Fig. 3). This is because the second crunch pressure PET of the boat 38 will also drain. In addition,
The second crunch control valve 17 is not limited to the structure shown in FIG. 7, but may be replaced by a three-way valve 25 shown in FIG. 2.

Next, the operation of the shift valve 14 will be explained.

Figure 3 shows the 1st speed state, where the first solenoid pressure P, the first solenoid pressure
Since both solenoid pressures PSZ are draining, the spools 30 and 31 are pushed to the right end position in contact by the line pressure P+ input to the left end boat 33. Therefore, the second clutch pressure PC from the boat 38! only is outputted and supplied to the second clutch C2 via the second clutch control valve 17. Therefore, the table,
As shown in (2), only the second clutch C2 is engaged, and the other friction elements are released.

FIG. 4 shows the second speed state, where the line pressure PL is input to the boat 33 at the left end, and the second solenoid pressure P is input to the boat 46 at the right end. is being input, the spools 30 and 31 are held at the center position in contact.

Therefore, the first brake engagement pressure P is applied from the boat 36.

is output, and the second clutch pressure Pc! is output from the boat 38.42. is output, the second clutch Ct and the first brake b are engaged as shown in Table 1, and the other friction elements are released.

FIG. 5 shows the third speed state, where the line pressure PL is input to the boat 33 at the left end, the first solenoid pressure ps+ is input to the boat 39, 40 at the center, and the second solenoid pressure P iz is input to the boat 46 at the right end. is entered.

1st. Since the pressure receiving area of each land of the second spool 30 and 31 is set as shown in (1) 2, the pressure receiving area of each land of the second spool 30.
0 is pushed to the left end position, and the second spool 31 is also pushed to a position where it comes into contact with the stepped portion 32 and stops there.

Therefore, the third clutch pressure P0 is applied from the boat 35, the first brake engagement pressure P0 is applied from the boat 36, and the second clutch pressure P0 is applied from the boat 42.
The first brake release pressure P□• is output from the clutch pressure PC2% port 44, respectively. In particular, the first brake release pressure P Ill is equal to the third clutch pressure P. , is the boat 35.
It was supplied via 45.

Therefore, as shown in Table 1, the second. 3rd Krasochi C,,
C, is engaged, and the first brake b1 is released.

FIG. 6 shows the 4th speed state, and the line pressure PL is input to the boat 33 at the left end, and the first solenoid pressure Ps+ is input to the boat 39.40 at the center, so the spool 30.3
1 is pushed to both end positions in a separated state.

Therefore, the third clutch pressure PC2 is output from the boat 35, and the first brake engagement pressure P is output from the boat 36.
□ is output, and as shown in Table 1, the third clutch C1 and the first
Brake b is engaged and the other friction elements are released.

In addition, the shift valve of the above embodiment has the second clutch C2.
, the case in which the third clutch C3 and the first brake b are engaged and released is shown, but the invention is not limited to this. Furthermore, the gear transmission mechanism used in combination with the friction element is limited to the Ravignaux-type planetary gear mechanism. do not have.

〔Effect of the invention〕

As is clear from the above explanation, according to the present invention, two spools arranged in series are provided in the shift valve, and signal hydraulic pressure is guided from two solenoid valves to the shift valve, thereby providing four spools. Since the operating position was realized,
All 1st to 4th gears can be changed with a single shift valve. Therefore, the hydraulic circuit is extremely simplified, reliability can be improved, and since it is sufficient to supply hydraulic pressure to the friction element from a single shift valve, the hydraulic pressure rises quickly. Furthermore, since the signal oil pressure of the electromagnetic valve only needs to be supplied to a single shift valve, a delay in the rise of the signal oil pressure can be eliminated, and a speedy shift operation can be realized.

[Brief explanation of the drawing]

FIG. 1 is a skeleton diagram of the power transmission mechanism of the automatic transmission according to the present invention, FIG. 2 is its hydraulic circuit diagram, and FIGS. 3 to 6 are structural diagrams of the first to fourth speeds of the shift valve. FIG. 7 is a structural diagram of the second clutch control pulp. C,, C, Cs...clutch, b+, Bz...brake, OWC...one-way clutch, 3...servo piston, 4...planetary gear mechanism, 14...shift valve, 15 ...First solenoid valve, 16... Second solenoid valve, 17... Second clutch control valve, 30
...first spool, 31...second spool. Patent applicant Daihatsu Motor Co., Ltd. Agent Patent attorney Hidetaka Tsutsukata Figures 1-7

Claims (1)

[Scope of Claims] In a hydraulic control device for an automatic transmission that switches four forward gears,
A single shift valve that can switch between 4 speeds,
Generates signal hydraulic pressure to operate the shift valve 2
The shift valve has a first spool and a second spool arranged in series, and the signal hydraulic pressure of the first solenoid valve is guided to an intermediate position between the first spool and the second spool. , the signal hydraulic pressure of the second solenoid valve is guided to the end of the second spool, and when both solenoid valves do not generate signal hydraulic pressure, the first and second
The first operating position is when the spool is in contact with one end, and the first and second operating positions are set when only the second solenoid valve generates a signal hydraulic pressure.
a second operating position in which the spools are in a contact state and located in the middle; a third operating position in which the first and second spools are in a separated state and located at the other end when both solenoid valves generate a signal hydraulic pressure; When only the first solenoid valve generates signal oil pressure, the first and second solenoid valves
A hydraulic control device for an automatic transmission, characterized in that the spool has a fourth operating position at both ends in a spaced-apart state.