JP3439616B2 - Hydraulic control device for automatic transmission - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydraulic control system for an automatic transmission, and more particularly to a hydraulic control system for a mechanical automatic transmission.

[0002]

2. Description of the Related Art Conventionally, as mechanical automatic transmissions having a forward four-speed gear, those disclosed in, for example, Japanese Patent Laid-Open Nos. 4-131565 and 4-131566 are known. As shown in FIG. 1, this automatic transmission includes a torque converter 1, an input shaft 2 to which engine power is transmitted via the torque converter 1, and three clutches C1, C.
2, C3, band brake b1, B2 brake, servo piston 3 for engaging and releasing band brake b1, Ravigneaux type planetary gear mechanism 4, one-way clutch OWC,
An output gear 5, an output shaft 7, a differential device 8 and the like are provided.

Forward sun gear 4a of the planetary gear mechanism 4
And the input shaft 2 are connected via a C1 clutch,
The rear sun gear 4b and the input shaft 2 are connected via a C2 clutch, and the carrier 4c and the input shaft 2 are connected via a C3 clutch. The carrier 4c is connected to a fixed member 6 such as a casing via a B2 brake and a one-way clutch OWC that allows only the normal rotation (engine rotation direction) of the carrier 4c. The carrier 4c supports two types of planetary gears 4d and 4e, the forward sun gear 4a meshes with a long pinion 4d having a long shaft length, and the rear sun gear 4b meshes with a long pinion 4d via a short pinion 4e having a short shaft length. There is.
The ring gear 4f, which meshes only with the long pinion 4d, is coupled to the output gear 5. The output gear 5 is connected to the differential device 8 via the output shaft 7.

The power transmission mechanism includes clutches C1 and C.
2, C3, brakes b1, B2, and one-way clutch OWC are operated to realize four forward gears and one reverse gear as shown in Table 1. In the following table, ○ indicates the operating state. In addition, B1 shows the engagement side oil chamber of the servo piston 3, B1 'shows the release side oil chamber of the servo piston 3, and when hydraulic pressure is introduced into both oil chambers B1 and B1' (at the 3rd speed). The band brake b1 is released.

[0005]

[Table 1]

[0006]

In the case of the above automatic transmission, the oil chamber B on the disengagement side of the C1 clutch and the servo piston 3 is provided.
There are provided a servo control valve that switches to the 2 position for supplying / discharging the hydraulic pressure to 1 ', and a 4-2 timing valve for always passing the 3rd speed when downshifting from the 4th speed to the 2nd speed.

2 at one end of the servo control valve
-3 Hydraulic pressure rising from shift valve at 3rd and 4th speed P _C3
Is input, and the hydraulic pressure P _{C2 of the} C2 clutch is input in the opposite direction. The hydraulic pressure P _{C2 of the} C2 clutch is continuously input during the upshift from the 2nd speed to the 3rd speed, so the servo control valve maintains the low speed stage side, and the servo control valve does not operate at the high speed for the 3rd speed → 4th speed. Switch to the tier side. On the other hand, when downshifting from the 4th speed to the 3rd speed, the hydraulic pressure P _C3 is continuously input, so the servo control valve maintains the high speed stage side, and the 3rd speed → 2nd speed.
Only after downshifting to high speed, the gear shifts to the low speed side. Thus, on the high speed stage side, the C1 clutch and the release side oil chamber B are
The hydraulic pressure 1'is drained together, and the hydraulic pressure P _{C2 of the} C2 clutch is supplied to the C1 clutch and the disengagement side oil chamber B1 'on the low speed stage side. That is, since the hydraulic pressure P _C2 of the C2 clutch is used as the source pressure of the C1 clutch and the release side oil chamber B1 ′, the hydraulic pressure is always supplied to the C1 clutch and the release side oil chamber B1 ′ after the C2 clutch is engaged. , It can reduce shift shock.

Further, the hydraulic pressure P _{C2 of the} C2 clutch is input to one end of the 4-2 timing valve, and it is urged by a spring so as to face the hydraulic pressure P _C2 . When the hydraulic pressure P _C2 is high (1-
(3rd speed), when the governor pressure P _G is input to the governor pressure input port of the 2-3 shift valve and the hydraulic pressure P _C2 becomes low (4
Fast time) is the governor pressure input port of the 2-3 shift valve line pressure P _L is input.

If the servo control valve and the 4-2 timing valve having the respective functions are individually provided as described above, there is a problem that the hydraulic circuit becomes complicated and large, and the cost increases.

Therefore, an object of the present invention is to provide a hydraulic control device for an automatic transmission which can simplify the hydraulic circuit by performing the functions of the servo control valve and the 4-2 timing valve with one valve. is there.

[0011]

In order to achieve the above object, the present invention has a C1, C2, C3 clutch and a band brake b1, and a servo piston for operating the band brake b1 is a coupling side oil chamber B1. And release side oil chamber B1 '
And the hydraulic pressure is supplied to the C2 clutch at the 1st speed.
The hydraulic pressure is supplied to the C2 clutch and the engagement side oil chamber B1 at the speed, the hydraulic pressure is supplied to the C1, C2 and C3 clutches at the third speed, and the hydraulic pressure is supplied to the engagement side and the release side oil chambers B1 and B1 '. In the automatic transmission configured so that the band brake b1 is released and hydraulic pressure is supplied to the C3 clutch and the engagement side oil chamber B1 at the 4th speed, a 1-2 shift valve that switches between the 1st speed side and the 2nd speed side Hydraulic pressure is supplied to and discharged from the 2-3 shift valve that switches between the 2nd speed side and the 3rd speed side, the 3-4 shift valve that switches between the 3rd speed side and the 4th speed side, the C1 clutch and the disengagement side oil chamber B1 ′. Therefore, a servo control valve that switches between the high speed stage side and the low speed stage side is provided, and the servo control valve has a port to which the output pressure P _C3 from the 2-3 shift valve is input to _urge the high speed stage side. , Low Provided a port pressure P _C2 of the clutch C2 for biasing the stage is input, and a port for supplying hydraulic pressure to hold the 2-3 shift valve to the high speed stage side in the state has been switched to a high-speed gear side The servo control valve is set to switch to the low speed stage side after the hydraulic pressure P _C2 has risen to the hydraulic pressure that can be engaged by the C2 clutch at the time of downshifting from the 4th speed.

The hydraulic pressures P _C3 and P _C2 are opposed to each other on the servo control valve during upshifting from the second speed to the third speed, but the low speed side is maintained by the hydraulic pressure P _C2 . Therefore, in the third speed, the hydraulic pressure P _C3 is supplied to the C1 clutch and the disengagement side oil chamber B1 ′. When upshifting from the 3rd speed to the 4th speed, the hydraulic pressure P _C2 is drained, and the servo control valve is switched to the high speed side. Therefore, the C1 clutch and the oil chamber B1 ′ are drained.

On the other hand, at the time of downshifting from the 4th speed to the 3rd speed, the hydraulic pressure P _C2 rises first, and after the C2 clutch is engaged, the servo control valve switches to the low speed side. Therefore, the C1 clutch is engaged with a delay and the shock can be reduced. Also, when you perform a quick kickdown,
The 2-3 shift valve and the 3-4 shift valve are switched to the low speed side at the same time, and a direct downshift from the 4th gear to the 2nd gear may occur, which may cause a large shift shock. Since the port for supplying the hydraulic pressure for holding the 3-shift valve at the high speed stage side is provided, the 2-3 shift valve is switched to the low speed stage side after the 3-4 shift valve is switched to the low speed stage side.
That is, since the vehicle always travels through the third speed, the shift shock can be reduced.

As a port for supplying a hydraulic pressure for holding the 2-3 shift valve at the high speed stage side, a governor pressure port to which a governor pressure P _G corresponding to a vehicle speed is inputted and a line pressure are provided. and the line pressure port P _L is input, 2-3 provided a shift valve governor pressure input port and the output port, communicating with the output port and the governor pressure port when the servo control valve is in the low speed stage side However, the output port and the line pressure port may be communicated with each other at the high speed stage side. Further, as described in claim 3, a throttle pressure port into which the throttle pressure P _T corresponding to the throttle opening is input, a drain port,
An output port connected to the throttle pressure input port of the 3-shift valve is provided so that the output port and the throttle pressure port communicate with each other when the servo control valve is on the low speed stage side, and the output port and the drain port when the servo control valve is on the high speed stage side. And may communicate with each other. In either case, 2-
Existing port of 3 shift valve (governor pressure input port,
Since the throttle pressure input port) can be used, it is not necessary to change the 2-3 shift valve. Needless to say, a port for holding the high speed stage may be separately provided in the 2-3 shift valve.

Further, the line pressure port to which the line pressure P _L in claim 2 is input is connected to the line D from the manual valve.
The range pressure P _D may be input, the oil pressure P _B1 rising from the 1-2 shift valve at the 2nd to 4th speeds may be input, and the line pressure P _L may be input from the regulator valve. In short, during at least 2-4 speed may be a port governor pressure P _G higher line pressure P _L is input.

To prevent excessive torque from being input to the gear train during downshifting from the 4th speed to the 3rd speed,
It is necessary to fasten the C2 clutch faster than the C1 clutch. Therefore, conventionally, an accumulator that delays the timing of hydraulic pressure supply to the C1 clutch has been provided, but this increases the size of the hydraulic circuit and does not necessarily provide stable characteristics. Therefore, it is preferable that the servo control valve is provided with a drain port communicating with the port connected to the C1 clutch at the high speed stage position. In this case, by draining the hydraulic pressure of the C1 clutch at the 4th speed, the hydraulic pressure supply timing to the C1 clutch can be delayed until the servo control valve is switched to the low speed stage side, and excessive torque is input to the gear train. You can certainly solve the problem.

[0017]

2 shows an example of a hydraulic control device according to the present invention. This hydraulic control device has three clutches C1, C2, C3 and two brakes b shown in FIG.
The present invention is applied to an automatic transmission equipped with 1 and B2 and operates as shown in Table 1. The hydraulic control device includes an oil pump 10, a regulator valve 11, a manual valve 12, a throttle valve 13, and a 1-2 shift valve 1.
4, 2-3 shift valve 15, 3-4 shift valve 1
6, governor valve 17, throttle modulator valve 18, 2-3 timing valve 19, 2-4 timing valve 20, 3-2 timing valve 21, 4-3 timing valve 22, servo control valve 23, 3
-4 & select timing valve 24, solenoid valve 25 for overdrive, modifier valve 2
6, a secondary regulator valve 27, a B1 accumulator 28, a C2 clutch accumulator 29, and the like.

Of the above hydraulic control device, the structure except the 2-3 shift valve 15 and the servo control valve 23 is not directly related to the present invention, so a detailed description is omitted and the hydraulic pressure of each oil passage is as follows. Only list them. That is, P _L
Is the line pressure, P _D is the line pressure in the D range, P _{2 and L} are 2
Range, line pressure at L range, P _R at retreat line pressure, P _T at throttle pressure, P _K at kick down pressure, P _TM
Is a throttle modulator pressure, P _G is a governor pressure, P _C1 is a C1 clutch pressure, P _C2 is a C2 clutch pressure, P _C3 is a C3 clutch pressure, P _B1 is a b1 brake engagement pressure, P _{B1 ′} is a b1 brake release pressure, P _B2 is the B2 brake pressure.

FIG. 3 shows a hydraulic circuit of a main part of the present invention.
2-3 shift valve 15 as is well known, switched to the second speed side and the third-speed side, the first speed, the OFF (drain) at the time of second speed, third speed, ON to the fourth speed (= P _L) to C3 clutch pressure It is a valve that outputs P _C3 . This valve 15 is equipped with a spool 15b which is pushed to the right by a spring 15a, and a governor pressure P _{G which} is substantially proportional to the vehicle speed is input to the right end port 15c via the servo control valve 23, so that the spool 15b is moved to the left. Pushing down. In addition, a constant pressure up to a constant throttle opening and a throttle modulator pressure P _TM equal to the throttle pressure P _T are input to the port 15d at a higher throttle opening.
Throttle pressure P _T is introduced to e and 15f. Furthermore, the kick-down pressure P _{K that} is the same as the throttle pressure P _T is input to the port 15g only during kick-down, and the line pressure P _{2, L} is input to the port 15h during the L and 2 ranges. The spool 15b is pushed to the right by hydraulic pressure. The port 15i is a drain port, the C3 clutch pressure P _C3 is output from the output port 15j, and the b1 brake engagement pressure P _B1 (hydraulic pressure rising at the 2nd to 4th speeds) is input from the 1-2 shift valve 14 to the input port 15k. Has been done. In the L and 2 ranges, the line pressure P _{2, L} input to the port 15h is also input to the left end spring chamber 15l via the communication hole of the spool 15b.
In L and 2 ranges, it always maintains second gear.

The servo control valve 23 supplies and discharges hydraulic pressure to and from the C1 clutch and the oil chamber B1 '.
-3 is a valve for controlling the shift valve 15.
This valve 23 is equipped with a spool 23b pushed to the left by a spring 23a, and the spool 23b is
At the 1st to 3rd speeds, it is at the left side position (low speed stage side) as shown in FIG. 3, and at the 4th speed, it is at the right side position (high speed stage side) as shown in FIG. In the two ports 23c and 23d on the left side,
The output pressure P _C3 of the 2-3 shift valve 15 is supplied through the one-way valve 40 and the orifice 41 which allow only the drained oil. The third port 23e from the left is connected to the C1 clutch, and the fourth port 23f is a drain port.
The governor pressure P _G is input from the governor valve 17 to the fifth port 23g from the left, and the sixth port 23h is 2-
It is connected to the right end port 15c of the 3-shift valve 15. Further, the line pressure P _{D in the} D range is input from the manual valve 12 to the seventh port 23i, and the eighth port 23j allows only refueling while the left two via the valve 42 and the orifice 43. Port 23c, 2
It is connected to 3d. The ninth port 23k from the left is connected to the release side oil chamber B1 ′ of the servo piston 3. The C2 clutch pressure P _C2 is introduced from the 3-4 shift valve 16 to the tenth port 231 from the left and the eleventh port (right end spring chamber) 23m. As is clear from Table 1, this hydraulic pressure P _C2 is high in the first to third speeds and is drained in the fourth speed. An oil passage for supplying the oil pressure P _C2 to the port 23l is provided with a one-way valve 44 and an orifice 45 in parallel to allow only oil supply, and an oil passage for supplying the oil pressure P _C2 to the port 23m. Is provided with a one-way valve 46 and an orifice 47 arranged in parallel to allow only drained oil.

The load Sp of the spring 23a increases after the hydraulic pressure P _C2 input to the port 23m at the time of downshifting from the 4th speed to the hydraulic pressure at which the C2 clutch can be engaged.
A relatively low load is set so that the spool 23b is switched to the left side (low speed stage side). That is, when shifting from the 4th speed to the 3rd speed, the C2 clutch pressure P _{C2 of the} port 23m
Is the accumulator 30 for the C2 clutch and the orifice 47.
By the action of, the rise occurs with a gradual characteristic as shown in FIG. Then, when the C2 clutch pressure P _C2 rises to the predetermined hydraulic pressure P _A , the C2 clutch is almost engaged. However, even at this time, the sum of the spring load Sp and the C2 clutch pressure P _C2 is lower than the C3 clutch pressure P _C3 (= P _L ) input to the left end port 23c, so that the servo control valve 23 is on the right side (high speed stage side). ) Holds position.
Eventually, when the sum of the spring load Sp and the C2 clutch pressure P _C2 becomes higher than the C3 clutch pressure P _C3 , the servo control valve 23 switches to the left side (low speed stage side). In this way, the servo control valve 23 is switched to the low speed stage side after the hydraulic pressure P _C2 has risen to the hydraulic pressure that can be engaged by the C2 clutch, so that the C1 clutch is engaged later than the C2 clutch and the shock can be reduced.

In the 4th speed → 3rd speed, the hydraulic pressure is supplied to the disengagement side oil chamber B1 'almost at the same time as the rise of the C2 clutch pressure P _C2. However, the hydraulic pressure is already supplied to the engagement side oil chamber B1. This is because there is no problem even if the hydraulic pressure is immediately supplied to the disengagement side oil chamber B1 ′.

The operation of the hydraulic circuit will now be described with reference to FIGS.
Will be described with reference to. 2-3 in 1st and 2nd speed
The shift valve 15 is at the right position and the hydraulic pressure P _C3 is drained. Therefore, the servo control valve 2
3 is also on the left side, and the C1 clutch and the release side oil chamber B
1'is also drained.

When shifting from the 2nd speed to the 3rd speed, the 2-3 shift valve 15 is switched to the left side, and the hydraulic pressure P is supplied from the port 15j.
_C3 (= P _L ) is output. However, C2 is still in the right end port 23m of the servo control valve 23.
Since the clutch pressure P _C2 is being supplied, the spring 23
The pressing force to the left is large by the load of a, and the servo control valve 23 holds the left position. At the third speed, the hydraulic pressure P _C3 is supplied to the C1 clutch and the disengagement side oil chamber B1 ′ via the servo control valve 23, so that the C1 clutch is engaged and the band brake b1 is released.

When shifting from the 3rd speed to the 4th speed, the C input to the right end port 23m of the servo control valve 23
Since the 2-clutch pressure P _C2 is drained, the servo control valve 23 is switched to the right position as shown in FIG. As a result, the hydraulic pressure of the C1 clutch is the drain port 2
The open side oil chamber B1 ′ is also drained in communication with the port 23l. Further, since the D range pressure P _D is input to the right end port 15c of the 2-3 shift valve 15 via the ports 23i and 23h of the servo control valve 23, the 2-3 shift valve 15 is forced to the left ( It is pushed in the 3rd speed direction) and holds the 3rd speed position.

When shifting from the 4th speed to the 3rd speed, as shown in FIG.
The 2-clutch pressure P _C2 gradually rises, and the C2 clutch is engaged first. After that, when the sum of the spring load Sp and the C2 clutch pressure P _C2 becomes higher than the C3 clutch pressure P _C3 , the servo control valve 23 is switched to the left side. In the disengagement side oil chamber B1 ′, the C2 clutch pressure P _C2 is applied to the port 23 before the servo control valve 23 is switched.
Since the pressure is temporarily supplied via 1, 23k, it rises together with the C2 clutch pressure P _C2 and the band brake b1 can be released relatively quickly. On the other hand, since the hydraulic pressure of the C1 clutch does not rise until the servo control valve 23 is switched, the hydraulic pressure of the C1 clutch is engaged later than the engagement of the C2 clutch. Therefore, it is possible to downshift to third gear without shock. In addition, until the servo control valve 23 is switched to the left side, the right end port 15 of the 2-3 shift valve 15 is
Since the D range pressure P _D is input to c, the 2-3 shift valve 15 holds the third speed position. Therefore, 4th gear → 2
It is possible to prevent direct shifting to high speed.

When shifting from the third speed to the second speed, the 2-3 shift valve 15 is switched to the right side and the hydraulic pressure P _C3 is drained. Therefore, the hydraulic pressures of the C1 clutch and the disengagement side oil chamber B1 'are also passed through the servo control valve 23. Be drained. Therefore, the C1 clutch is released and the band brake b1 is engaged.

The present invention is not limited to the above embodiment. In the above embodiment, when downshifting from the 4th speed,
In order that the servo control valve 23 is switched to the low speed stage side after the hydraulic pressure P _C2 has risen to the hydraulic pressure at which the C2 clutch can be engaged, the spring 2 urging the low speed stage side.
Although 3a is provided, instead of this, the port 2 that urges toward the low speed stage from the pressure receiving area of the port 23c that urges toward the high speed stage
The pressure receiving area of 3 m may be increased.

Further, in order to hold the 2-3 shift valve 15 on the high speed stage side (third speed position), the port 23h of the servo control valve 23 is connected to the governor pressure input port 15c, and the governor pressure P _G is connected to the port 23g. , And the D range pressure P _D was input to the port 23i, but instead of this,
The port 23h may be connected to the throttle pressure input ports 15f and 15e of the 2-3 shift valve 15, the throttle pressure P _T may be input to the port 23g, and the port 23i may be a drain port.

Further, the drain port 23f is provided to drain the hydraulic pressure of the C1 clutch when the servo control valve 23 is switched to the high speed side, but the drain port 23f is not limited to this, and for example, the port 23f may be set to C2.
It may be connected to an oil passage to which the clutch pressure P _C2 is supplied.

[0031]

As is apparent from the above description, according to the present invention, the C1 clutch and the servo piston disengagement side oil chamber B are formed.
The servo control valve for supplying / discharging hydraulic pressure to 1'and the function of the 4-2 timing valve for passing through the 3rd speed when downshifting from the 4th speed to the 2nd speed are performed by one valve. , The hydraulic circuit can be simple and downsized,
This has the effect of reducing costs.

[Brief description of drawings]

FIG. 1 is a schematic mechanism diagram of an automatic transmission having a forward fourth speed.

FIG. 2 is an overall circuit diagram of a hydraulic control device according to the present invention.

FIG. 3 is a circuit diagram of a main part of a hydraulic control device according to the present invention.

FIG. 4 is a circuit diagram of a main part of the hydraulic control device according to the present invention at a fourth speed.

FIG. 5 is a hydraulic pressure change diagram of C2 clutch pressure at the time of 4th speed → 3rd speed.

[Explanation of symbols]

C1 C1 clutch C2 C2 clutch C3 C3 clutch 3 Servo piston b1 band brake B1 Connection side oil chamber B1 'Release side oil chamber 14 1-2 Shift valve 15 2-3 shift valve 16 3-4 Shift valve 23 Servo control valve

Claims (4)

(57) [Claims] 1. A C1, C2, C3 clutch and a band brake b1, and a servo piston for operating the band brake b1 has an engagement side oil chamber B1 and a release side oil chamber B1 '. The hydraulic pressure is supplied to the C2 clutch, the hydraulic pressure is supplied to the C2 clutch and the engagement side oil chamber B1 in the second speed, the hydraulic pressure is supplied to the C1, C2 and C3 clutches in the third speed, and the engagement side and the release side oil chambers are supplied. In the automatic transmission configured such that the hydraulic pressure is supplied to B1 and B1 'to release the band brake b1 and the hydraulic pressure is supplied to the C3 clutch and the engagement side oil chamber B1 at the 4th speed, the 1st speed side and the 2nd speed side 1-2 shift valve that switches to, a 2-3 shift valve that switches to 2nd speed side and 3rd speed side, a 3-4 shift valve that switches to 3rd speed side and 4th speed side, C1 clutch and release side oil To room B1 ' It is equipped with a servo control valve that switches between a high speed stage side and a low speed stage side to supply and discharge hydraulic pressure. The servo control valve has an output pressure P _C3 from the 2-3 shift valve for energizing the high speed stage side. Oil pressure for holding the 2-3 shift valve on the high speed side while switching to the high speed side and the port for inputting the oil pressure P _{C2 of the} C2 clutch for urging to the low speed side Is provided, and the servo control valve is set so as to switch to the low speed side after the hydraulic pressure P _C2 has risen to a hydraulic pressure that can be engaged by the C2 clutch at the time of downshifting from the 4th speed. A hydraulic control device characterized in that 2. A port for supplying a hydraulic pressure for holding the 2-3 shift valve on the high speed stage side, a governor pressure port into which a governor pressure P _G corresponding to a vehicle speed is input, and a line pressure P _L are input. Line pressure port and an output port connected to the governor pressure input port of the 2-3 shift valve. When the servo control valve is on the low speed side, the output port and the governor pressure port communicate with each other The hydraulic control device according to claim 1, wherein the output port and the line pressure port communicate with each other when on the stage side. 3. A port for supplying a hydraulic pressure for holding the 2-3 shift valve on the high speed stage side includes a throttle pressure port to which a throttle pressure P _T corresponding to a throttle opening is input, a drain port, 2-3 Shift valve consisting of throttle pressure input port and connected output port. When the servo control valve is on the low speed side, the output port communicates with the throttle pressure port, and on the high speed side, the output port. The hydraulic control device according to claim 1, wherein the drain port and the drain port communicate with each other. 4. The servo control valve according to claim 1, further comprising a drain port communicating with a port connected to the C1 clutch at a high speed stage position. Hydraulic control device.