JPH04151065A - Hydraulic control device for automatic transmission - Google Patents

Abstract

PURPOSE:To ensure the synchronous state of two frictional engaging elements by discharging an oil pressure from two oil chambers through a common drain port during the shift of a transmission from a high speed to a middle speed and discharging the oil pressure through a different common port for drain during the shift thereof from a high speed to a low speed. CONSTITUTION:When a shift from a fourth speed state to a third speed is commanded, a first shift valve 50 is shifted and an oil pressure in a low clutch disengaging chamber 22b and an oil pressure in an apply chamber 28c for a hand brake fourth speed are discharged through a common drain port 50e. An oil pressure is reduced in a synchronized state, a hand brake 28 is disengaged, and a low clutch 22 is engaged. When a 4-2 shift is commanded, simultaneously with the shift of the first shift valve 50, a spool 52a of the second shift valve 52 is switched. An oil pressure in the low clutch disengaging chamber 22b and an oil pressure in a high clutch oil chamber 20a are discharged through a common drain port 90a and reduced in a synchronized state, and disengagement of a high clutch 20 and engagement of the low clutch 22 are effected in synchronism with each other.

Description

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

(b) Conventional technology As a conventional hydraulic control device for an automatic transmission,
There is one shown in Japanese Patent No. 156757. The automatic transmission shown here has four forward speeds, and has three clutches, two brakes, and one one-way clutch for speed change control. The low clutch is engaged in 1st, 2nd and 3rd gears, and the high clutch is engaged in 3rd and 4th gears.

Further, the band brake is engaged in the second speed and the fourth speed. Therefore, when the low clutch and band brake are engaged, the second gear is set, when the low clutch and the high clutch are engaged, the third gear is set, and when the high clutch and the band brake are engaged, the third gear is set. It becomes 4 speed. In the case of shifting from 4th speed to 3rd speed, the band brake is released and the low clutch is engaged. In this case, the shift timing is adjusted by adjusting the release pressure for releasing the band brake and the rise of the low clutch pressure for engaging the low clutch. In the case of shifting from 4th speed to 2nd speed, the high clutch is released and the low clutch is engaged. In this case, the shift timing is adjusted by adjusting the drop in high clutch pressure and the rise in low clutch pressure. The low clutch has one piston, which is actuated by hydraulic pressure that acts on all conditions, and is pushed back by a spring, so the only operating pressure is the hydraulic pressure for engaging the low clutch. Further, the band brake has an apply chamber for tightening and a release chamber for releasing, and there are two types of operating pressure: apply pressure and release pressure that are supplied to both chambers. Therefore, four types of operating pressures are involved in shifting between second, third, and fourth speeds. However, only two oil pressures (rise oil pressure or falling oil pressure) are changed in order to realize shifting between these gear stages. Therefore, in the case of 4-3 shifting and 4-2 shifting, it is only necessary to adjust the timing of two oil pressures, respectively.

(c) Problems to be Solved by the Invention However, even when using a planetary gear train similar to the one shown in the above publication, the servo device that controls the band brake has three oil chambers, that is, three oil chambers for second speed. An apply chamber, a release chamber for 3rd speed, and an apply chamber for 4th speed are provided, and if the low clutch is provided with two oil chambers, that is, an apply chamber for low clutch and a release chamber for low clutch, 2nd speed, Six types of operating pressures are available for shifting between 3rd and 4th speeds: high clutch pressure, low clutch pressure,
/W rx-force a m d-171+-i τr1'-
The L' brake apply pressure for 2nd speed, the release pressure for band brake 3rd speed, and the apply pressure for band brake 4th speed are involved. In particular, the low clutch release pressure is 4-
It changes at the same time as the band brake 4th gear apply pressure during the 3rd gear shift, and changes simultaneously with the high clutch pressure during the 4-2 gear shift. Therefore, it is necessary to adjust the low clutch release pressure so that it changes in a predetermined relationship with the band brake 4th speed apply pressure, and also to adjust it so that it changes in a predetermined relationship with the high clap pressure. Conventional technology has not shown any means for solving such problems. This invention is like this! ! The purpose is to solve problems.

(D) Means for Solving the Problems The present invention provides communication with each oil chamber in the case of shifting between a high gear and a middle gear, and in the case of shifting between a high gear and a low gear. The above problem is solved by switching the connection state of the oil passage. That is, the present invention.

First frictional engagement element (20), second frictional engagement element (22)
The fastening element has a first oil chamber (20a) that fastens when hydraulic pressure is applied, and a second friction fastening element. has a second oil chamber (22a) and a third oil chamber (22b), and when oil pressure is applied to the second oil chamber and no oil pressure is applied to the third oil chamber, the second oil chamber is replaced by the third oil chamber. 2. Fasten the friction fastening elements,
The third oil chamber is configured to release the second friction engagement element when hydraulic pressure acts on it, regardless of the operating state of the oil pressure in the second oil chamber, and the third friction engagement element is configured to release the second friction engagement element in the fourth oil chamber ( 28a), the fifth oil chamber (28b) and the sixth oil chamber (28c)
), and when hydraulic pressure is applied to the fourth oil chamber and no hydraulic pressure is applied to the fifth oil chamber, the third friction engagement element is engaged; When the hydraulic pressure is applied to the sixth oil chamber, the third frictional engagement element is released regardless of the operating state of the hydraulic pressure in the fourth oil chamber. It is configured to fasten three frictional fastening elements, and hydraulic pressure acts on the second oil chamber and the fourth oil chamber, and the hydraulic pressure acts on the first oil chamber, the third oil chamber, the fifth oil chamber, and the sixth oil chamber. Low gear (second gear) when hydraulic pressure is not applied
Medium speed is achieved when hydraulic pressure acts on the first, second, fourth and fifth oil chambers, and no oil pressure acts on the third and sixth oil chambers. When a high stage (3rd speed) is achieved and hydraulic pressure acts on the first, second, third, fourth, fifth and sixth oil sacs, a high speed stage (third speed) is achieved. This device is intended for hydraulic control devices for automatic transmissions that achieve a 4-speed transmission.The shift valve (52) for speed change control, which can be switched between low and medium speeds, controls the 3rd oil It is possible to switch the oil passage connected to the chamber, and at low speeds, this shift valve connects the first oil chamber and the third oil chamber and transfers the oil pressure in the inner oil chamber to the first drain port (90a). Let it drain,
The third oil chamber and the sixth oil chamber are connected to each other during the middle speed stage, and the hydraulic pressure in the inner oil chamber is discharged from the second drain port (50e). Note that the symbols in parentheses indicate corresponding members in the embodiments described later.

(E) Operation When shifting from a high gear to a middle gear, the oil pressure in the third oil chamber and the oil pressure in the sixth oil chamber are discharged. In this case, the third oil chamber and the sixth oil chamber are connected by the shift valve and are discharged from the second drain port, so it is possible to set the oil pressure discharge timing only for the oil pressure in the inner oil chamber. can. On the other hand, in the case of shifting from a high gear to a low gear, the oil pressure in the first oil chamber and the oil pressure in the third oil chamber are discharged. In this case as well, the first oil chamber and the third oil chamber are communicated with each other by the shift valve and are discharged from the first drain port, so the discharge timing of the hydraulic pressure in the inner oil chamber only applies to the oil pressure in the inner oil chamber. Can be set as .

(F) Embodiments Hereinafter, embodiments of the present invention will be described based on FIGS. 1 to 4 of the accompanying drawings.

FIG. 2 shows a schematic diagram of a power transmission mechanism of an automatic transmission with four forward speeds and one reverse speed with an overdrive. This power transmission mechanism includes an input shaft 13 to which rotational force from an engine output shaft 12 is transmitted via a torque converter 10, an output shaft 14 that transmits driving force to the final drive device, a first planetary gear set 15, and a second planetary gear set. Group 16, reverse clutch 1
8, a high clutch 20, a low clutch 22, a low and reverse brake 26, a band brake 28, and a row one-way clutch 29. Note that the torque converter 10 has a lock-up clutch 11 built therein. The first planetary gear set 15 is composed of a sun gear S1, an internal gear R1, and a carrier PCI that supports a pinion gear P1 that meshes with both gears 81 and R1 at the same time. ,
It is composed of an internal gear R2 and a carrier PC2 that supports a pinion gear P2 that meshes with both gears S2 and R2 at the same time. Carrier PC1 is high clutch 2
0, and the sun gear S1 can be connected to the input shaft 13 via a reverse clutch 18. Carrier Pct can also be connected to internal gear R2 via low clutch 22. Sun gear S2 is always connected to human power shaft 13, and internal gear R1 and carrier PC2 are always connected to blade shaft 14. The low and reverse brake 26 can fix the carrier Pct, and the band brake 28 can fix the sun gear S1. The row one-way clutch 29 is arranged in an orientation that allows forward rotation (rotation in the same direction as the engine output shaft 12) of the carrier PCI, but does not allow reverse rotation (rotation in the opposite direction to the forward rotation). In addition, high clutch 20, reverse clutch 18,
The low and reverse brake 26 has one oil chamber on one side of one piston and is pushed back by a return spring, but the low clutch 2
2 has two pistons, whereby a low clutch apply chamber 22a and a low clutch release chamber 2
2b is formed, and a low clutch release chamber 22b
When hydraulic pressure is supplied to the low clutch apply chamber 22a with no hydraulic pressure acting on the low clutch apply chamber 22a, the low clutch 22 is engaged.On the other hand, when hydraulic pressure is supplied to the low clutch release chamber 22b, no hydraulic pressure is applied to the low clutch apply chamber 22a. The low clutch 22 is configured to be released even when it is supplied. The hydraulic servo device of the band brake 28 has three oil chambers partitioned by two pistons, as shown in FIG.
It has an apply chamber (2A) 28a for speed, a release chamber (3R) 28b for band brake 3rd speed, and an apply chamber (4A) 28c for band brake 4th speed. If hydraulic pressure acts on the band brake 2nd speed apply chamber 28a while no hydraulic pressure is acting on the band brake 3rd speed release chamber 28b, the band brake 28 is engaged, and on the other hand, the band brake 3rd speed release chamber 28b has hydraulic pressure applied. When this is applied, the band brake 28 is released regardless of the state of the oil pressure in the band brake 2nd speed apply chamber 28a.

Furthermore, when hydraulic pressure is supplied to the band brake 4th speed apply chamber 28c, the band brake 2nd speed apply chamber 28a
The band brake 28 is engaged regardless of the operating state of the hydraulic pressure in the band brake 3rd speed release chamber 28b.

The power transmission mechanism includes clutches 18, 20, and 22,
By operating the brakes 26 and 28 in various combinations, each element (Sl,
Sl, R1, R2, Pct, and PC2) can be changed, thereby making it possible to variously change the rotational speed of the output shaft 14 relative to the rotational speed of the input shaft 13. Clutches 18, 20, and 22, and brakes 26
and 28 in combination as shown in FIG. 4, four forward speeds and one reverse speed can be obtained. In addition,
The middle lower half of Figure 1 shows the oil chamber where hydraulic pressure is applied.

Figure 1 shows the hydraulic circuit. Note that FIG. 1 only shows valves directly related to the present invention.

This hydraulic circuit includes a first shift valve 50 and a second shift valve 52.
, and a 4-2 sequence valve 54, which are connected as shown in the figure, and also have a low clutch release chamber 22b (third oil chamber) and a high clutch oil chamber 2.
0a (first oil chamber), band brake 4-speed application chamber 2
8c and the band brake 3rd speed release chamber 28b as shown.

The first shift valve 50 includes a spool 50g and a spring 50.
b, and the spool 50a is switched by a solenoid signal pressure applied from the boat 50c. That is,
The spool 50a is located at the position shown in the lower half of FIG. 1 during the first and fourth speeds, and is located at the upper half of FIG. 1 during the second and third speeds. Therefore, during the first and fourth speeds, the oil passage 70 and the oil passage 72 communicate with each other, and the oil passage 74 communicates with the drain port 50d. Note that oil pressure is supplied to the oil passage 7o from a manual valve (not shown) during forward movement. On the other hand, in the second and third speeds, the oil passage 72 communicates with the drain port 50e, and the oil passage 74 communicates with the oil passage 70.

The second shift valve 52 includes a spool 52a and a spring 52.
b, and is switched by a solenoid signal pressure that is applied from the boat 52c and is different from the above-mentioned solenoid signal pressure. That is, the spool 52a is located at the position shown in the upper half of FIG. 1 during the first and second speeds, and is located at the position shown in the lower half of FIG. 1 during the third and fourth speeds. therefore,
At first and second speeds, the oil passage 92 is connected to the oil passage 90, the oil passage 93 is connected to the oil passage 90, the oil passage 82 and the oil passage 84 are connected, and the oil passage 80 is connected to the drain port 52d. be done. On the other hand, in the third and fourth gears, the oil passage 72 and the oil passage 8
2 are connected, oil passage 7° and oil passage 80 are connected, oil passage 80 and oil passage 93 are connected, and oil passage 72 and oil passage 9 are connected.
2 is connected. The oil passage 82 communicates with the band brake fourth speed apply chamber 28c. The oil passage 8o communicates with the band brake third speed release chamber 28b.

The oil passage 92 communicates with the low clutch release chamber 22b. The oil passage 90 is drained from a drain port 90a.

The 4-2 sequence valve 54 has a spool 54a and a spring 54b, and switches depending on the oil pressure acting on the boat 54c from the oil passage 8o.

That is, when the oil pressure of the boat 54c is low, the condition is shown in the lower half of FIG. 1, and the oil passage 84 is connected to the drain port 54d.
and also connects the oil passage 80 and the oil passage 88. On the other hand, when the oil pressure of the boat 54c becomes high, the oil passage 74 and the oil passage 84 are connected, and the oil passage 88 and the oil passage 93 are connected. The oil passage 88 communicates with the high clutch oil chamber 20a.

Next, the operation of this embodiment will be explained.

At the fourth speed, the spool 50a of the first shift valve 50 is in the first
In the figure, the spool 52a of the second shift valve 52 is also located in the lower half position. Therefore, the first shift valve 50 connects the oil passage 70 and the oil passage 72, and the second shift valve 52 connects the oil passage 72 and the oil passage 82, so the band brake 4th speed apply chamber 28c
Hydraulic pressure acts on the Moreover, since the oil passage 70 and the oil passage 80 are communicated with each other by the second shift valve 52, oil pressure acts on the band brake third speed release chamber 28b. Further, the oil passage 88 communicating with the high clutch oil chamber 20a is connected to the oil passage 9 by a 4-2 sequence valve 54 located in the upper half position in FIG.
3, and the oil passage 93 is connected to the second shift valve 52.
Since the high clutch oil chamber 20a is connected to the oil passage 80 by the high clutch oil chamber 20a, hydraulic pressure also acts on the high clutch oil chamber 20a. In addition, the second shift valve 5
2 connects the oil passage 72 and the oil passage 92.

Therefore, oil pressure also acts on the low clutch release chamber 22b. As a result, the low clutch release chamber 22b,
High clutch oil chamber 20a, band brake 4th speed apply chamber 28c, and band brake 3rd speed release chamber 28b
Hydraulic pressure will act on all of them. Due to the stiffness, the high clutch 2° and the band brake 28 are in an engaged state, resulting in a fourth speed state.

When a shift from the fourth speed state to the third speed is commanded, the hydraulic pressure that was acting on the boat 50c of the first shift valve 50 ceases to act, and the first shift valve 5° is moved to the upper half in FIG. Switch to the state of the section. Therefore, the oil passage 72 is connected to the drain port 5.
It will be connected to 0e. Therefore, the oil pressure in the low clutch release chamber 22b is controlled by the oil passage 92 and the second shift valve 5.
2. The oil pressure is discharged from the drain port 50e via the oil passage 72 and the first shift valve 5o, and the oil pressure in the band brake 4th speed apply chamber 28c is also discharged through the oil passage 82, the second shift valve 52,
It is discharged from the drain port 50e via the oil passage 72 and the first shift valve 5o. That is, the oil pressure in the low clutch release chamber 22b and the oil pressure in the band brake 4th speed apply chamber 28c are discharged from the common drain port 50e, and the oil pressures decrease in a synchronous state. This results in
The band brake 28 is released and the low clutch 22 is engaged. As mentioned above, the hydraulic pressure of the low clutch release chamber 22b and the band brake 4-speed application chamber 2
Since the hydraulic pressure of 8c is discharged from the common drain boat 50e, the band brake 28 is released and the low clutch 2
The conclusion in step 2 is performed synchronously. Moreover, this synchronized state is maintained regardless of the operating conditions.

Next, when a 4-2 shift is commanded, the spool 52a of the second shift valve 52 is also switched from the lower half position to the upper half position in the figure at the same time as the first shift valve 5o is switched. Therefore, the oil passage 8o is connected to the drain boat 52d, and the hydraulic pressure acting on the band brake 3rd speed release chamber 28b is discharged from the train port 52d. The oil pressure in the low clutch release chamber 22b is supplied to the drain port 90a via the oil passage 92, the second shift valve 52, and the oil passage 90.
is discharged from. In addition, the oil pressure in the high clutch oil chamber 20a is controlled by the oil passage 88.4-2 sequence valve 54 and the oil passage 93.
, the second shift valve 52, and the oil passage 90, and are discharged from the drain port 90a. As a result, the oil pressure in the low clutch release chamber 22b and the oil pressure in the high clutch oil chamber 20a are discharged from the common train port 90a and decrease in a synchronous manner. That is, high clutch 20
The release of the low clutch 22 and the engagement of the low clutch 22 are performed synchronously.

Incidentally, during the 4-2 shift, the oil pressure in the band brake 4th gear apply chamber 28c is reduced as follows. That is,
Before the oil pressure in the oil passage 80 is sufficiently reduced, the 4-2 sequence valve 54 is held in the upper half position in FIG. 54
It is connected to the On the other hand, the first shift valve 50 is located at the upper half position in FIG. Therefore, the oil passage 70 and the oil passage 74 are connected. Therefore, the oil pressure in the oil passage 70 is controlled by the first shift valve 50, the oil passage 74.4-2 sequence valve 54.
, the oil passage 84, the second shift valve 52, and the oil passage 82 to the band brake fourth speed apply chamber 28c, and the band brake 28 is maintained in the engaged state. That is,
The fourth speed state is maintained. Next, as the gear shift progresses and the hydraulic pressure in the band brake 3rd speed release chamber 28b decreases, the hydraulic pressure acting on the port 54c of the 4-2 sequence valve 54 decreases, and the spool 54a moves as shown in the lower half of FIG. state. Therefore, the oil passage 84 is connected to the drain port 5.
4d, and thereby the hydraulic pressure of the band brake 4th gear apply chamber 28c is connected to the oil passage 82, the second shift valve 52,
It is discharged from the drain port 54d via the oil passage 84 and the 4-2 sequence valve 54. As a result, the engaged state of the band brake 28 is maintained by the hydraulic pressure in the band brake 4th speed apply chamber 28c. That is, since the hydraulic pressure in the band brake 4th gear apply chamber 28c decreases after the hydraulic pressure in the handbrake 3rd gear release chamber 28b decreases, the band brake 28 is not released during the shift, and from 4th gear onwards. The gear will be shifted directly to second gear.

Next, for reference, 3-2 shifting will also be explained. In the third speed state, the first shift valve 50 is in the upper half position in FIG. 1, and the second shift valve 52 is in the upper half position in FIG. It is located in the lower half of the diagram J1. As a result, the low clutch release chamber 22b,
Hydraulic pressure is supplied to the high clutch oil chamber 20a and the band brake third speed release chamber 28b. When the second shift valve 52 is switched to the upper half position from this state, the hydraulic pressure in the band brake 3rd speed release chamber 28b is changed to the oil passage 80 and the second shift valve 52.
It is discharged from the drain port 52d via the shift valve 52. Furthermore, the oil pressure in the high clutch oil chamber 20a is also controlled by the oil passage 88.
．． It is discharged from the drain port 52d via the 4-2 sequence valve 54, the oil passage 80, and the second shift valve 52.

Therefore, in this case as well, the hydraulic pressure in the high clutch oil chamber 20a and the band brake 3rd speed release chamber 28b is discharged from the common drain port 52d, and the high clutch 20
The release of the band brake 28 and the engagement of the band brake 28 are performed synchronously.

(g) As described in detail, according to the present invention, when shifting from a high gear to a middle gear, the hydraulic pressure in the two oil chambers that is discharged at this time is discharged from a common drain port. Furthermore, when shifting from a high gear to a low gear, the hydraulic pressure in the oil chamber that is discharged at this time is discharged from another common train port, so that the two friction The synchronized state of the fastening elements is reliably ensured, and the shift timing can be easily and appropriately set. Furthermore, according to the present invention, since a shift valve is used in the above configuration, there is no need to add a special valve.

[Brief explanation of the drawing]

Fig. 1 is a diagram showing a hydraulic circuit according to an embodiment of the present invention, Fig. 2 is a skeleton diagram of an automatic transmission, Fig. 3 is a diagram showing a hydraulic servo device for a pand brake, and Fig. 4 is a diagram showing a hydraulic servo device for a pand brake. It is a figure which shows the hydraulic operation state to each oil chamber. 20a... High clutch oil chamber, 22b... Low clutch release chamber, 28c... Apply chamber for band brake 4th speed, 28b... Release chamber for band brake 3rd speed, 50... First shift valve, 50e Drain port, 52 Second shift valve, 52d Drain port, 54 ・4-2 sequence valve, 90a Drain port. Patent applicant: Jatco Co., Ltd. Representative: Patent attorney: Toshiyuki Miyauchi

Claims (1)

[Claims] First frictional engagement element (20), second frictional engagement element (22)
and a first frictional engagement element (28), the first frictional engagement element has a first oil chamber (20a) that engages the fluid when hydraulic pressure is applied, and the second frictional engagement element has a second oil chamber (20a) that engages the fluid when hydraulic pressure is applied. It has a chamber (22a) and a third oil chamber (22b), and when hydraulic pressure is applied to the second oil chamber and no hydraulic pressure is applied to the first oil chamber, the second oil chamber is a second frictional engagement element. The third oil chamber closes the second oil chamber when hydraulic pressure is applied to it.
The second frictional engagement element is configured to be released regardless of the operating state of the oil pressure in the oil chamber, and the third frictional engagement element is connected to the fourth oil chamber (28a), the fifth oil chamber (28b), and the sixth oil chamber. The fourth oil chamber has a chamber (28c), and when hydraulic pressure is applied to this fourth oil chamber, and when no hydraulic pressure is applied to the fifth oil chamber, the third oil chamber
The friction engagement element is engaged, and the fifth oil chamber releases the first friction engagement element regardless of the operating state of the oil pressure in the fourth oil chamber unless hydraulic pressure is acting on the sixth oil chamber when hydraulic pressure is applied thereto. The sixth oil chamber is configured to engage the second frictional engagement element when hydraulic pressure acts on it, and while the hydraulic pressure acts on the second and fourth oil chambers, the first
A low gear is achieved when oil pressure does not act on the oil chamber, the third oil chamber, the fifth oil chamber, and the sixth oil chamber, and the first oil chamber, the second oil chamber, the fourth oil chamber, and the fifth oil chamber When hydraulic pressure is applied and no hydraulic pressure is applied to the third oil sac and the sixth oil sac, a middle gear is realized. 5
In a hydraulic control device for an automatic transmission in which a high gear is achieved when hydraulic pressure acts on the oil chamber and the sixth oil chamber, a shift valve for gear change control that can be switched between a low gear and a middle gear is used. 5
2) makes it possible to switch the oil passage connected to the first oil chamber, and this shift valve connects the first oil chamber and the third oil chamber to control the oil pressure in both oil chambers during low gears. It is configured to discharge the hydraulic pressure from the first drain port (90a), connect the third oil chamber and the sixth oil chamber at middle speed, and discharge the hydraulic pressure in both oil chambers from the second drain port (50e). A hydraulic control device for an automatic transmission characterized by: