JP2889352B2 - Hydraulic control device for automatic transmission - Google Patents

Description

The present invention relates to a hydraulic control device for an automatic transmission.

(B) Conventional technology A conventional hydraulic control device for an automatic transmission is disclosed in
There is one disclosed in Japanese Patent No. 156757. The automatic transmission shown therein is of a forward fourth speed, and has three clutches, two brakes, and one one-way clutch for speed change control. The low clutch is engaged in first, second and third speeds, and the high clutch is engaged in third and fourth speeds.
The band brake is engaged at the second speed and the fourth speed. Therefore, the second speed is established when the low clutch and the band brake are engaged, the third speed is established when the low clutch and the high clutch are engaged, and the second speed is established when the high clutch and the band brake are engaged. Fourth speed. In the case of shifting from the fourth speed to the third speed, the hand brake is released and the low clutch is engaged. In this case, the shift timing is adjusted by adjusting the rise of 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 the fourth speed to the second speed, the high clutch is released and the low clutch is engaged. In this case, the shift timing is adjusted by adjusting the decrease of the high clutch pressure and the rise of the low clutch pressure. Since the low clutch has one piston and is operated by hydraulic pressure acting on one side of the piston and is pushed back by a spring, the operating pressure is only the hydraulic pressure for engaging the roller clutch. Further, the band brake has an apply chamber for engaging and a release chamber for releasing the band brake. The operating pressure is two pressures of the apply pressure and the release pressure supplied to both chambers.
Kind. Therefore, four types of operating pressures are involved in shifting between the second speed, the third speed, and the fourth speed. However, there are only two hydraulic pressures (rising hydraulic pressure or decreasing hydraulic pressure) that change in order to realize a shift between these shift speeds. Therefore, in the case of the 4-3 shift and the 4-2 shift, the timing of each of the two hydraulic pressures may be adjusted.

(C) Problems to be Solved by the Invention However, even when the same gear train as the planetary gear train disclosed in the above-mentioned publication is used, the servo device for controlling the band brake has three oil chambers, that is, two gear chambers. When an apply chamber is provided with a third-speed release chamber and a fourth-speed apply chamber, and two oil chambers are provided in the roller clutch, that is, a low-clutch apply chamber and a low-clutch release chamber, the second-speed and the second-clutch are provided. Six types of operating pressures for shifting between the third speed and the fourth speed, namely, high clutch pressure, low clutch apply pressure, roller clutch release pressure, band brake second speed apply pressure, band brake third speed release pressure and band brake 4 Speed application pressure will be involved.
In particular, the low clutch release pressure changes simultaneously with the apply pressure for the fourth speed of the band brake during the 4-3 shift,
At the time of -2 shift, it changes simultaneously with the high clutch pressure. For this reason, it is necessary to adjust the low clutch release pressure so as to change in a predetermined relationship with the band brake fourth speed apply pressure, and to adjust the low clutch release pressure so as to change in a predetermined relationship with the high clutch pressure. Means for solving such a problem are not shown in the prior art. An object of the present invention is to solve such a problem.

(D) Means for Solving the Problems The present invention communicates with each oil chamber in the case of a shift between a high speed stage and a middle speed stage and in the case of a shift between a high speed stage and a low speed stage. The above problem is solved by switching the connection state of the oil passage. That is, the present invention provides a first friction fastening element (20),
A second frictional engagement element (22) and a third frictional engagement element (28), wherein the first frictional engagement element has a first oil chamber (20a) that engages when hydraulic pressure is applied; The two-friction fastening element has a second oil chamber (22a) and a third oil chamber (22b), and when the oil pressure acts on the second oil chamber, no oil pressure acts on the third oil chamber. In this case, the second frictional engagement element is engaged, and the third oil chamber is configured to release the second frictional engagement element when hydraulic pressure acts on the second frictional engagement element regardless of the state of the hydraulic pressure in the second oil chamber. , The third friction fastening element is a fourth oil chamber (28a), a fifth oil chamber (28b), and a sixth oil chamber (28c).
The fourth oil chamber engages the third friction engagement element when the hydraulic pressure is not acting on the fifth oil chamber when the hydraulic pressure acts on the fourth oil chamber, and the fifth oil chamber has the hydraulic pressure applied thereto. When the oil pressure acts on the sixth oil chamber, the third frictional engagement element is released regardless of the state of the oil pressure in the fourth oil chamber, unless the oil pressure acts on the sixth oil chamber. It is configured to fasten the friction fastening element, and hydraulic pressure acts on the second oil chamber and the fourth oil chamber, and hydraulic pressure acts on the first oil chamber, the third oil chamber, the fifth oil chamber, and the sixth oil chamber. Does not act on the low speed stage (second
Speed) is realized, and hydraulic pressure acts on the first oil chamber, the second oil chamber, the fourth oil chamber, and the fifth oil chamber, and when the hydraulic pressure does not act on the third oil chamber and the sixth oil chamber, the medium speed When the oil pressure acts on the first oil chamber, the second oil chamber, the third oil chamber, the fourth oil chamber, the fifth oil chamber, and the sixth oil chamber, a high gear (third speed) is realized. 4
And a switching valve (60) capable of switching an oil passage connected to a third oil chamber is provided. Is switched between the low speed stage and the middle speed stage. At the low speed stage, the first oil chamber and the third oil chamber are connected to discharge the oil pressure of both oil chambers from the first drain port (90a). During the stage, the third oil chamber and the sixth oil chamber
The oil chambers are connected to each other to discharge the oil pressure of both oil chambers from the second drain port (50e). In addition, the code | symbol in a parenthesis shows the corresponding member of the Example mentioned later.

(E) Function In the case of shifting from the high speed stage to the middle speed stage, the hydraulic pressure of the third oil chamber and the hydraulic pressure of the sixth oil chamber are discharged. In this case, since the third oil chamber and the sixth oil chamber are connected by the switching valve and are discharged from the second drain port, the discharge timing of the hydraulic pressure can be set only for the hydraulic pressures of both the oil chambers. it can. On the other hand, in the case of a shift 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. Also in this case, since the first oil chamber and the third oil chamber are brought into communication with each other by the switching valve and are discharged from the first drain port, the discharge timing of the oil pressure of both oil chambers is limited to the oil pressure of both oil chambers. Can be set as

(F) Embodiment Hereinafter, an embodiment of the present invention will be described with reference to FIGS.

FIG. 2 is a skeleton diagram showing a power transmission mechanism of an automatic transmission having four forward speeds and one reverse speed with an overdrive. This power transmission mechanism includes an input shaft 13 to which torque from an engine output shaft 12 is transmitted via a torque converter 10, an output shaft 14 to transmit driving force to a final drive device, a first planetary gear set.
15, second planetary gear set 16, reverse clutch 18, high clutch 20, low clutch 22, low and reverse brake
26, band brake 28, low one-way clutch 29
have. The torque converter 10 has a lock-up clutch 11 built therein. The first planetary gear set 15 includes a carrier PC1 that supports a sun gear S1, an internal gear R1, and a pinion gear P1 that meshes with both gears S1 and R1 at the same time.
And the planetary gear set 16 includes a sun gear
S2, 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. The carrier PC1 can be connected to the input shaft 13 via the high clutch 20, and the sun gear S1 can be connected to the input shaft 13 via the reverse clutch 18. The carrier PC1 is connected to the internal gear R via the low clutch 22.
Both can be connected. The sun gear S2 is always connected to the input shaft 13, and the internal gear R1 and the carrier PC
2 is always connected to the output shaft 14. The low and reverse brake 26 can fix the carrier PC1, and the band brake 28 can fix the sun gear S1. Low one-way clutch 29 is a carrier
The PC1 is arranged in such a direction that forward rotation (rotation in the same direction as the engine output shaft 12) is allowed but reverse rotation (rotation in the opposite direction to the forward rotation) is not allowed. In addition, the high clutch 20, the reverse clutch 18,
And the low and reverse brake 26 has a single oil chamber on one side of one piston and is pushed back by a return spring, while the low clutch 22 has two pistons, thereby The clutch apply chamber 22a and the low clutch release chamber 22b are formed, and when the hydraulic pressure is supplied to the low clutch apply chamber 22a in a state where the hydraulic pressure is not acting on the low clutch release chamber 22b, the low clutch 22 is engaged. When the hydraulic pressure is supplied to the low clutch release chamber 22b, the low clutch 22 is released even when the hydraulic pressure is supplied to the low clutch apply chamber 22a.
As shown in FIG. 3, the hydraulic servo device of the band brake 28 has three oil chambers divided by two pistons, that is, an apply chamber (2A) 28 for the second speed of the band brake.
a, a release chamber (3R) 28b for the third speed of the band brake and an apply chamber (4A) 28c for the fourth speed of the band brake. When the hydraulic pressure is not acting on the release chamber 28b for the third speed band brake, the apply chamber 28a for the second speed brake band
When the hydraulic pressure acts on the band brake 28, the band brake 28 is engaged. On the other hand, when the hydraulic pressure acts on the release chamber 28b for the third speed band brake, the band brake 28 Is released.
When hydraulic pressure is supplied to the band brake fourth speed apply chamber 28c, the band brake 28 is engaged regardless of the operating state of the hydraulic pressure in the band brake second speed apply chamber 28a and the band brake third speed release chamber 28b. .

The power transmission mechanism operates each of the elements (S1, S2, R1, R2, PC2) of the planetary gear sets 15 and 16 by operating the clutches 18, 20, and 22, and the brakes 26 and 28 in various combinations.
1, and the rotation state of the PC 2) can be changed, whereby the rotation speed of the output shaft 14 with respect to the rotation speed of the input shaft 13 can be variously changed. By operating the clutches 18, 20, and 22 and the brakes 26 and 28 in a combination as shown in FIG. 4, it is possible to obtain four forward speeds and one reverse speed. In FIG. 4, a circle indicates an oil chamber in which hydraulic pressure is applied.

FIG. 1 shows a hydraulic circuit. FIG. 1 shows only valves directly related to the present invention.

This hydraulic circuit includes a first shift valve 50, a second shift valve 52,
It has a 4-2 sequence valve 54, a 4-2 relay valve 56, a high clutch pressure switching valve 58, and a low clutch pressure switching valve 60, which are respectively connected as shown in FIG. The third oil chamber), the high clutch oil chamber 20a (first oil chamber), the band brake fourth speed apply chamber 28c, and the band brake third speed release chamber 28b are also connected as shown. The first shift valve 50 is a spool 50
a and a spring 50b, and the spool 50a is switched by a solenoid signal pressure applied from a port 50c. That is, at the first and fourth speeds, the spool 50a
It is at the position shown in the upper half of the figure, and at the second and third speeds, it is at the position shown in the lower half of FIG. Therefore, at 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. The hydraulic pressure is supplied to the oil passage 70 from a manual valve (not shown) at the time of forward movement. On the other hand, at 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 76.

The second shift valve 52 has a spool 52a and a spring 52b, and is switched by a solenoid signal pressure different from the above-mentioned solenoid signal pressure acting from a port 52c.
That is, the spool 52a is at the position shown in the upper half of FIG. 1 at the first and second speeds, and is at the first position at the third and fourth speeds.
It is at the position shown in the lower half of the figure. Therefore, the first and second
At the time of speed, the oil passage 74 is connected to the oil passage 78, and the oil passage 80 is connected to the drain port 52d. Further, the oil passage 82 and the oil passage 84 are connected. On the other hand, at the third and fourth speeds, the oil passages 72 and 78
Are connected, the oil passage 70 and the oil passage 80 are connected, and the oil passage
82 is connected to the drain port 52d. The oil passage 78 communicates with the band brake fourth speed apply chamber 28c. Oil passage 80
Is in communication with the band brake third speed release chamber 28b.

The 4-2 sequence valve 54 includes a spool 54a and a spring 5
4b, and is switched according to the oil pressure acting on the port 54c from the oil passage 80. That is, when the oil pressure of the port 54c is low, the upper half of FIG. 1 is reached, and the oil passage 76 is connected to the drain port 54d, while when the oil pressure of the port 54c is high, the oil passage 76 and the oil passage 82 are connected. I do.

The 4-2 relay valve 56 has a spool 56a and a spring 56b, and switches between an upper half position and a lower half position in the figure according to the oil pressure acting on the port 56c from the oil passage 78. That is, when the oil pressure of the port 56c is low, the oil passage 84 is connected to the drain port 56d, and when the oil pressure of the port 56c is high, the oil passage 84 is connected.
84 and the oil passage 70 are connected.

The high clutch pressure switching valve 58 has a spool 58a and a spring 58b, and the spool 58a switches between an upper half position and a lower half position in the figure according to the oil pressure acting on the port 58c. The 4-2 shift signal hydraulic pressure acts on the port 58c.
Therefore, at the time of the 4-2 shift, the spool 58a is at the upper half position, and the oil passage 88 and the oil passage 90 are connected. On the other hand, 3-
The oil passage 88 is connected to the oil passage 80 during the second shift. The oil passage 88 communicates with the high clutch oil chamber 20a. The oil passage 90 is drained from a drain port 90a.

The low clutch pressure switching valve 60 has a spool 60a and a spring 6
0b, and the spool 60a switches between the upper half position and the lower half position in FIG. 1 according to the oil pressure acting on the port 60c. The signal pressure output at the third and fourth speeds acts on the port 60c. Therefore, at the third and fourth speeds, the spool 60a is at the upper half position in FIG. 1 to connect the oil passage 72 and the oil passage 92, while at the first and second speeds, the oil passage 92 and the oil passage
Connect with 90. Oil passage 92 is low clutch release oil chamber 22
Communicates with b.

Next, the operation of this embodiment will be described. At the fourth speed, the spool 50a of the first shift valve 50 is at the upper half position in FIG. 1, while the spool 52a of the second shift valve 52 is at the lower half position. Therefore, the oil passage 70 and the oil passage 72 are connected by the first shift valve 50, and the oil passage 72 and the oil passage 78 are connected by the second shift valve 52. Hydraulic pressure works. Further, since the oil passage 70 and the oil passage 80 are communicated by the second shift valve 52,
The hydraulic pressure acts on the release chamber 28b for the third speed of the band brake. The oil passage 80 is connected to the oil passage 88 by a high clutch pressure switching valve 58 located at a lower half position in FIG. 1, and the hydraulic pressure also acts on the high clutch oil chamber 20a. The low clutch pressure switching valve 60 is located at the upper half position in FIG. 1 by a signal pressure acting on the port 60c, and connects the oil passage 72 and the oil passage 92. Therefore, the low clutch release chamber 22b
The hydraulic pressure also acts. As a result, the hydraulic pressure acts on all of the low clutch release chamber 22b, the high clutch oil chamber 20a, the band brake fourth speed apply chamber 28c, and the band brake third speed release chamber 28b. As a result, the high clutch 20 and the band brake 28 are engaged, and the fourth speed state is established.

When the shift from the fourth speed state to the third speed is commanded,
The hydraulic pressure acting on the port 50c of the first shift valve 50 stops working, and the first shift valve 50 switches to the state of the lower half in FIG. Therefore, the oil passage 72 is connected to the drain port 50e. Accordingly, the oil pressure in the low clutch release chamber 22b is discharged from the drain port 50e through the oil passage 92, the low clutch pressure switching valve 60, the oil passage 72 and the first shift valve 50, and the band brake fourth speed apply chamber 28c
Is discharged from the drain port 50e through the oil passage 78, the second shift valve 52, the oil passage 72, and the first shift valve 50. That is, the oil pressure in the low clutch release chamber 22b and the oil pressure in the band brake fourth speed apply chamber 28c are discharged from the common drain port 50e, and the oil pressure decreases at the same speed. As a result, the band brake 28 is released and the low clutch 22 is engaged. As described above, since the hydraulic pressure of the low clutch release chamber 22b and the hydraulic pressure of the band brake fourth speed apply chamber 28c are discharged from the common drain port 50e, the release of the band brake 28 and the engagement of the low clutch 22 are synchronized. Done. Moreover, this synchronization state is maintained regardless of the operating conditions.

Next, when the 4-2 shift is instructed, the spool 52 of the second shift valve 52 is simultaneously switched with the first shift valve 50.
a is also switched from the lower half position to the upper half position in the figure. Therefore, the oil passage 80 is connected to the drain port 52d, and the hydraulic pressure acting on the band brake third speed release chamber 28b is discharged from the drain port 52d. Since the signal pressure acting on the port 60c of the low clutch pressure switching valve 60 disappears, the low clutch pressure switching valve 60 is switched to the lower half position in FIG. 1, and the high clutch pressure switching valve 58 is also connected to the port 58c. 4-2 is shifted to the upper half position in FIG. Therefore, the oil passage 92 is a low clutch pressure switching valve.
The oil passage 90 is connected to the oil passage 90 by 60, and the oil passage 88 is connected to the oil passage 90 by the high clutch pressure switching valve 58. The oil pressure in the oil passage 90 is discharged from the drain port 90a. As a result, the hydraulic pressure in the low clutch release chamber 22b and the high clutch oil chamber 2
The hydraulic pressure of 0a is discharged from the common drain port 90a and decreases in a synchronized state. That is, the high clutch 20
Is released and the engagement of the low clutch 22 is synchronized.

At the time of the 4-2 shift, the hydraulic pressure in the band brake fourth speed 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 at the lower half position in FIG. Connected by 54. On the other hand, the 4-2 relay valve 56 is at the lower half position in FIG. Therefore, the oil passage 70 and the oil passage 84 are connected. For this reason, the oil pressure in the oil passage 70 is set to 4-2 relay valve.
56, oil passage 84, second shift valve 52, oil passage 82, 4-2 sequence valve 54, oil passage 76, first shift valve 50, oil passage 74, band brake through oil passage 78, and oil passage 78 The band brake 28 is supplied to the fourth speed application chamber 28c, and the engaged state of the band brake 28 is maintained. That is, the fourth speed state is maintained. Next, the shift progresses, and the release chamber 28 for the third speed band brake is operated.
When the oil pressure of b decreases, port 5 of 4-2 sequence valve 54
The hydraulic pressure acting on 4c decreases, and the spool 54a switches to the state shown in the upper half in FIG. Therefore, the oil passage 76 is connected to the drain port 54d, whereby the hydraulic pressure of the band brake fourth speed apply chamber 28c is reduced by the oil passage 78 and the second shift valve 5d.
2. The oil is discharged from the drain port 54d through the oil passage 74, the first shift valve 50, the oil passage 76, and the 4-2 sequence valve 54.
As a result, the engagement state of the band brake 28 is maintained by the hydraulic pressure of the band brake fourth speed apply chamber 28c. That is, since the oil pressure in the band brake fourth speed application chamber 28c decreases after the oil pressure in the band brake third speed release chamber 28b decreases, the band brake 28 is not released during the speed change, and the band brake 28 is released from the fourth speed. The transmission is directly shifted to the second speed.

Next, the 3-2 shift will be described for reference. In the third speed state, the first shift valve 50 is in the lower half position in FIG. 1, and the second shift valve 52 is in the lower half position in FIG. As a result, the low clutch release chamber 22b, the high clutch oil chamber 20a, and the band brake third speed release chamber 28b
Is supplied with hydraulic pressure. From this state, the second shift valve 52
Is switched to the upper half position, the hydraulic pressure in the release chamber 28b for the third speed of the band brake is discharged from the drain port 52d via the oil passage 80 and the second shift valve 52. The hydraulic pressure of the high clutch oil chamber 20a is also controlled by the oil passage 88, the high clutch pressure switching valve 58,
Drain port 52 via oil passage 80 and second shift valve 52
Exhausted from d. Accordingly, also in this case, the hydraulic pressure in the high clutch oil chamber 20a and the band brake third speed release chamber 28b is discharged from the common drain port 52d, and the release of the high clutch 20 and the engagement of the band brake 28 are performed in synchronization. .

Although the orifice and the accumulator are not provided in the above-described embodiment, for example, if an orifice is provided in the drain port 50e, the orifice and the accumulator are provided for the low clutch release oil chamber 22b and the hydraulic discharge of the band brake fourth speed apply chamber 28c. Orifice effect can be obtained. Further, for example, if an accumulator is provided in the oil passage 72, changes in oil pressure in both the low clutch release chamber 22b and the band brake fourth speed apply chamber 28c can be reduced by one accumulator, and the orifice and accumulator are provided in the oil passage 90. The same applies to the case in which the above is provided.

(G) Effects of the Invention As described above, according to the present invention, when shifting from the high speed stage to the middle speed stage, the oil pressure of the two oil chambers discharged at this time is discharged from the common drain port. When shifting from a high gear to a low gear, the oil pressure of the oil chamber discharged at this time is discharged from another common drain port. The synchronized state of the elements is reliably ensured, and the shift timing can be easily and appropriately set.

[Brief description of the drawings]

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 of a band brake, and FIG. It is a figure which shows the hydraulic operation state to each oil chamber. 20a… High clutch oil chamber, 22b… Low clutch release oil chamber, 28c… Apply chamber for band brake 4th speed, 28b
… Release room for band brake 3rd speed, 50… First shift valve, 50e… Drain port, 52 …… Second shift valve, 5
2d: drain port, 54: 4-2 sequence valve, 56
…… 4-2 relay valve, 58 …… High clutch pressure switching valve, 60
…… Low clutch pressure switching valve, 90a …… Drain port.

Claims (1)

(57) [Claims] A first frictional fastening element (20), a second frictional fastening element (22) and a third frictional fastening element (28), the first frictional fastening element being engaged when hydraulic pressure is applied. It has a first oil chamber (20a), and the second friction fastening element has a second oil chamber (22a) and a third oil chamber (22a).
b), the second oil chamber engages the second frictional engagement element when the oil pressure is not acting on the third oil chamber when the oil pressure acts on the second oil chamber. When the hydraulic pressure acts on the second oil chamber, the second frictional engagement element is released regardless of the operating state of the hydraulic pressure in the second oil chamber, and the third frictional engagement element is constituted by the fourth oil chamber (28a) and the fifth oil Room (28b)
And a sixth oil chamber (28c). The fourth oil chamber engages a third frictional engagement element when hydraulic pressure is not applied to the fifth oil chamber when hydraulic pressure is applied to the fourth oil chamber. The fifth oil chamber releases the third friction engagement element when the oil pressure acts on the sixth oil chamber, regardless of the state of operation of the oil pressure in the fourth oil chamber, unless the oil pressure acts on the sixth oil chamber. When hydraulic pressure acts on the third
It is configured to fasten the friction fastening element, and while hydraulic pressure acts on the second oil chamber and the fourth oil chamber,
When the oil pressure is not applied to the oil chamber, the third oil chamber, the fifth oil chamber, and the sixth oil chamber, the low speed stage is realized, and the first oil chamber, the second oil chamber, the fourth oil chamber, and the fifth oil chamber are provided. When the hydraulic pressure is applied and no hydraulic pressure is applied to the third oil chamber and the sixth oil chamber, a middle speed stage is realized, and the first oil chamber, the second oil chamber, the third oil chamber, the fourth oil chamber, and the 5
In a hydraulic control device for an automatic transmission in which a high-speed stage is realized when hydraulic pressure acts on the oil chamber and the sixth oil chamber, a switching valve (6) capable of switching an oil path connected to the third oil chamber is provided.
0) is provided, and this switching valve is switched between a low speed stage and a middle speed stage. At the low speed stage, the first oil chamber and the third oil chamber are connected to each other, and the oil pressure of both oil chambers is set to the first oil chamber. It is configured to discharge from the drain port (90a) and connect the third oil chamber and the sixth oil chamber at the middle speed to discharge the oil pressure of both oil chambers from the second drain port (50e). A hydraulic control device for an automatic transmission, characterized in that: