JPH0251656A - Speed change control device for automatic transmission - Google Patents

Abstract

PURPOSE:To obtain a desirable speed change feeling by constituting the title device so that the supply and discharge timing of the oil pressure in the oil chamber of the frictional element on one side can be controlled independently of that in the oil chamber of the frictional element on the other side. CONSTITUTION:When a 2-3 shift valve 26 is changed over from the discharge position to the supply position, the supply of oil pressure to an oil passage 32 is started. At the time the valve 26 is changed over, a timing regulation valve 40 is in the cutoff position. Therefore, the oil pressure in the oil passage 32 is supplied only to the oil chamber of a H&R/C (first frictional element) to start the rise of oil pressure therein. In the mean time, the oil chamber of S/R (second frictional element) is in a discharge condition. After a lapse of a prescribed time, an electronic control unit 58 operates a solenoid 94 to change over the valve 40 from the cutoff position to the communication position. As a result, the oil passage 32 is communicated with an oil passage 38 to start the supply of oil pressure to a S/R. Thus, a time difference in the rise of oil pressures between the H&R/C and the S/R can be provided, so that a desirable regulation of speed change timing can be enabled.

Description

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

(B) Prior Art A conventional speed change control device for an automatic transmission is disclosed in, for example, Japanese Patent Application Laid-Open No. 57-144338Aj. The shift control device for the automatic transmission shown therein has a 3-2 timing valve.

The 3-2 timing valve is a valve that adjusts the speed of oil discharged from the release side oil chamber (release chamber) of the hydraulic servo device of the band brake device. Hydraulic pressure is supplied from the 2-3 shift valve to the release chamber of the band brake device and the third clutch through the same oil passage. 3-2 The trimming valve is arranged in parallel with the orifice in an oil passage connected to the release chamber, and is capable of controlling the opening and closing of the oil passage that bypasses the orifice. When the vehicle speed is low, the bypass passage is communicated, so that the hydraulic pressure in the release chamber is rapidly discharged without being affected by the throttling effect.

On the other hand, when the vehicle speed increases, the bypass passage is blocked, so the hydraulic pressure in the release chamber is discharged through the orifice. By doing so, the time until the band brake is engaged can be adjusted depending on the vehicle speed.

(c) Problems to be solved by the invention However, the speed change i of the conventional automatic transmission as described above
(The control device has a problem in that it cannot perfectly adjust the timing. That is, when the 2-3 shift valve switches to 2nd gear, the clutch oil pressure starts to drain, and at the same time The hydraulic pressure in the release chamber also begins to be discharged.The discharge of this hydraulic pressure in the release chamber starts simultaneously in the clutch and the release chamber even when the timing valve blocks the bypass passage.However, the hydraulic pressure in the release chamber side starts to discharge. Because it is discharged through the orifice, the rate of decrease is slower than that on the clutch side.In this way, the start time of hydraulic discharge itself is the same for the clutch and the release chamber, so when the clutch is released and the release chamber It is difficult to set a sufficient time difference between the drop in oil pressure (i.e. engagement of the band brake).For this reason, it is not possible to set a sufficiently long neutral time during 3-2 gear shifting. , it is not possible to obtain a favorable shifting feeling.

In order to deal with such problems, Japanese Patent Application Laid-Open No. 63-9634
Publication No. 5 discloses that hydraulic pressure is directly supplied to the friction element from one switching valve, and a one-sided valve (arranged to allow only flow from the switching valve to the other friction element) is provided for the other friction element. A timing valve is shown in the oil passage on the other friction element side. However, even in this case, when the hydraulic pressure is discharged from both friction elements, the hydraulic pressure on one friction element side is I! of the other friction element. If the oil pressure becomes higher than the oil pressure on the rubbing element side, the oil will flow through the one-way valve and there will be no oil pressure difference, so the degree of freedom in timing adjustment will be reduced. One object of the present invention is to solve this problem.

(d) Means for Solving the Problems The present invention provides that one Pt friction element oil chamber and the other Jγ
Problem F is solved by making it possible to independently control the supply and discharge timing of hydraulic pressure in the oil chamber of the friction element. That is, the shift control device for an automatic transmission according to the present invention includes a shift valve (26), a timing adjustment valve (40) switched by a solenoid (94), and an electronic control unit (58). Spool (2
8) transfers the hydraulic pressure of the oil pressure source oil passage (18) to the first oil passage (32).
It is possible to switch between the supply position where the hydraulic pressure is supplied to the hydraulic pressure of the first oil passage and the discharge position where the hydraulic pressure of the first oil passage is discharged. It is connected to the valve, and the timing adjustment valve spool (4
2) is a communication 11γ position where the first oil passage and the second oil passage (38) are communicated with each other, and a blocking position where the first oil passage and the second oil passage are shut off and the second oil passage is discharged. The second oil passage is connected to the oil chamber (S/R) of the second friction element, and the electronic control unit outputs a timing adjustment valve switching signal after a predetermined time after the shift valve is switched. is configured to output to the solenoid. Note that the symbols in parentheses indicate corresponding members in the embodiments described later.

(e) Operation When the shift valve is switched from the discharge position to the supply position, supply of hydraulic pressure to the first oil path is started. At the time the shift valve is switched, the timing adjustment valve is in the shutoff position. Therefore, the oil pressure in the first oil passage is supplied only to the oil chamber of the first friction element, and the oil pressure therein starts to rise. During this time, the oil chamber of the second friction element is in a discharged state. After a predetermined period of time has elapsed, the electronic control unit operates a solenoid to switch the timing adjustment valve from the shutoff position to the open position. Therefore, the first oil passage and the second oil passage communicate with each other, and the supply of hydraulic pressure to the oil chamber of the second WE friction element is started.

In this way, the supply of hydraulic pressure to the oil chamber of the second friction element is started a predetermined time after the start of hydraulic pressure supply to the oil chamber of the first friction element. As a result, a time difference can be given to the rise of oil l and q in both oil chambers, and the shift timing can be adjusted as desired.

(F) Embodiments Hereinafter, embodiments of the present invention will be described based on FIGS. 1 to 3 of the accompanying drawings.

FIG. 2 shows a schematic diagram of the power transmission mechanism of an automatic transmission with three forward speeds and one reverse speed. This power transmission mechanism consists of a human power shaft ■ to which rotational force is transmitted from the engine output shaft E via a torque converter T/C, an output shaft 0 which transmits driving force to the final drive device, a first planetary gear set GI, and a second planetary gear set GI. It has a planetary gear set G2, a high and reverse clutch H&R/C, a forward clutch F/C, a band brake B, a low and reverse brake L&R/B, and a one-way clutch OWC. The first planetary gear set G includes a sun gear Sl, an internal gear R8, a single gear 81, and a gear R.
The planetary gear set G2 includes a sun gear S2, an internal gear R2, and both gears S.
2 and a carrier PC2 that supports a pinion gear P2 that meshes with R2 at the same time. Each component is connected as shown. "The power transmission mechanism described in Part 2 is
High and reverse clutch H&R/C, forward clutch F/C, band brake B and low and reverse brake L&R/B (one-way clutch 0WC)
By activating the combination of persimmons, the planetary tooth 1
Each element of 1L set G1 and G2 (s+, S2, R+,
The rotational state of R2, PC+ and pc, ) can be changed, thereby changing the output shaft O relative to the rotational speed of the human power shaft ■.
Three forward speeds and one reverse speed can be obtained by varying the rotational speed of.

FIG. 1 shows only the parts of the hydraulic circuit that are directly related to the present invention.

The 1-2 shift valve 10 is composed of a spool 12 and a spring 14, and the spool 12 communicates the oil passage 16 and the oil passage 18 at the lower half position in the figure, and communicates the oil passage 18 with the oil passage 18 at the upper half position in the figure. drain. The position of the spool 12 is determined by the hydraulic force acting on the boat 22 from the oil passage 20,
It is determined by the magnitude relationship with the force exerted by the spring 14.

Line pressure is always supplied to the oil passage 16 from a manual valve 24 during old roads. Note that the oil passage 16 is also connected to the forward clutch F/C.

The 2-3 shift valve 26, which is the shift valve targeted by the present invention, is composed of a spool 28 and a spring 30.
8 (hydraulic source oil passage) and oil passage 32 (first oil passage) are communicated with each other, and the oil passage 32 is drained at the upper half position in the figure. The position of the spool 28 is determined by the magnitude relationship between the hydraulic force acting on the boat 34 from the oil passage 70 and the force exerted by the spring 30. The oil passage 18 is connected to a servo apply chamber S/A for engaging the band brake B. Oil passage 32 is a high-ant reverse clutch H&R/C
(first Pf friction element), and also connected to the timing adjustment valve 40. Note that orifices 31 and 33 are provided at the branched portions of the oil passage 32, respectively.

The timing adjustment valve 40 is composed of a spool 42 and a spring 44. When the spool 42 is in the lower half position in the figure, the oil passage 32 and the oil passage 38 communicate with each other, and when the spool 42 is in the upper half position in the figure, the oil passage 32 and the oil passage 38 ( The second oil passage) and the oil passage 32 are cut off, and the oil passage 38 is drained from the drain boat 47. The drain boat 47 is provided with an orifice 35. The position of the spool 42 is determined by the magnitude relationship between the hydraulic force acting on the boat 46 from the oil passage 91 and the force exerted by the spring 44. The oil passage 38 is connected to a servo release chamber S/R for releasing the band brake B (second friction element). Note that the pressure receiving area of the servo release chamber S/R is larger than the pressure receiving area of the servo apply chamber S/A, so the servo release chamber S
When hydraulic pressure acts on /R, band brake B is always released.

The oil passage 20 described above is connected via an orifice 52 to an oil passage 50 to which a constant pressure is always supplied from a pilot pressure valve 48. The oil passage 20 is provided with an opening 54, and a 1-2 solenoid valve 56 that can open and close this opening 54 is provided. 1-2 solenoid valve 56
is switched on and off by No. 15 from the electronic control unit 58. The 1-2 solenoid valve 56 opens the opening 54 to discharge hydraulic pressure from the oil passage 20 when turned on, and closes the opening 54 to generate oil pressure in the oil passage 20 when turned off.

]) The oil passage 70 mentioned above is connected via an orifice 72 to an oil passage 50 to which constant pressure is always supplied from the pilot pressure valve 48. The oil passage 70 is provided with an opening lower 4, and a 2-3 solenoid valve 76 that can open and close the opening lower 4 is provided. The 2-3 solenoid valve 76 is turned on and off by means 1 and 1 from the electronic control unit 58. 2-3 Solenoid valve 7
6 opens the open II 74 when it is on and closes it when it is off. This turns on the oil pressure in the oil passage 70.
Can be turned off.

The oil passage 91 described above is connected via an orifice 92 to the oil passage 50 to which a constant pressure is always supplied from the pilot pressure valve 48. The oil passage 91 is provided with an opening 193, and a timing solenoid valve 94 that can open and close this opening 93 is provided. The timing solenoid valve 94 is switched on and off by a signal from the electronic control unit 58. The timing solenoid valve 94 opens the opening 93 when it is on, and closes it when it is off. Thereby, the oil pressure of the oil passage 91 can be turned on and off.

Electric signals from a vehicle speed sensor 60, a throttle opening sensor 62, etc. are manually inputted to the electronic t-control unit 58, and the electronic control unit 58 operates 1-2 based on these signals.
Solenoid valve 56.2-3 outputs a signal that controls the operation of solenoid valve 76 and timing solenoid valve 94.

Next, the operation of this embodiment will be explained. First, 1-
2 solenoid valve 56. 2-3 solenoid valve 76
When all of the timing solenoid valves 94 and 94 are off, hydraulic pressure is generated in the oil passage 20, oil passage 70, and oil passage 91, and the spool 12 of the 1-2 shift valve 10, the spool 28 of the 2-3 shift valve 26, and The spool 42 of the timing adjustment valve 40 is located halfway in FIG. Therefore, oil pressure is supplied only to the forward clutch F/C, and the automatic transmission is placed in the first speed state.

Next, when the 21-2 solenoid valve 56 is turned on, the oil pressure in the oil passage 20 is discharged, the spool 12 of the 1-2 shift valve 10 is switched to the lower half position, and the oil passage 16 and the oil passage 1
8, so hydraulic pressure is supplied to the servo apply chamber S/A. Therefore, band brake B is engaged,
The automatic transmission is in the second speed state.

Next, when the 2-3 solenoid valve 76 is turned on and the oil pressure in the oil passage 70 is released, the 2-3 shift valve 26
The spool 28 is in the lower half position, and the oil passage 18 and oil passage 3 are
2 are connected. Note that the timing solenoid valve 94 remains off at this point. For this reason, oil path 3
2 and the oil passage 38 are in a cutoff state, and the oil pressure of the oil passage 32 begins to be supplied only to the high and reverse clutch H&R/C. For this reason, the high and reverse clutch H&R/
As shown in FIG. 3, the oil pressure of C starts to rise as shown by the solid line from time t when the 2-3 shift valve 26 is switched. Next, at time t2 after a time Δ, the timing solenoid valve 94 is switched from off to on. As a result, the oil pressure in the oil passage 91 is discharged, and the spool 42 of the timing adjustment valve 40 is switched to the lower half position. When the spool 42 is switched to the half position, the oil passage 32 and the oil passage 3
8 is in communication with the servo release chamber S/
It also begins to be supplied to R. For this reason, the servo release chamber S
The oil pressure at /R starts to rise at time t2, as shown by the broken line in FIG. As a result, the oil pressure in the high and reverse clutch H&R/C and the servo release chamber S/R changes as shown in Figure 3, and the high and reverse clutch H&R/C is first engaged, and then the band brake B is released. become. In this way, since there is a time difference Δt between the start of engagement of the high and reverse clutch H&R/C and the start of release of the band brake B, the time difference Δt is provided between the start of engagement of the high and reverse clutch H&R/C and the start of release of the band brake B. As a result, the release is delayed, and both friction elements operate in an overlapping state, which prevents the engine from racing and provides an appropriate shift feeling. In addition,
The time Δt is made longer as the vehicle speed is higher, so that appropriate gear shifting can be performed under all gear shifting conditions.

In addition, in the case of 3-2 shifting, the 2-3 shift valve 26
The orifice effect when discharging the hydraulic pressure from the servo release chamber S/R can be changed by changing the timing adjustment valve 40 d with respect to the switching. That is, when the 2-3 shift valve 26 is switched from the lower half position to the upper half position in FIG. 1, the oil pressure in the oil passage 32 is discharged. For this reason, the high and reverse clutch H
The hydraulic pressure of &R/C will be discharged through the orifice 31, while the hydraulic pressure of the servo release chamber S/R will be discharged through the orifice 33.

2-3 When the timing adjustment valve 40 is switched from the F half position to the upper half position a predetermined time after the shift valve 26 is switched, the hydraulic pressure in the servo release chamber S/R will be discharged through the orifice 35. . This results in
It is possible to adjust the timing of shifting.

In addition, when the switching of the 2-3 shift valve is performed by hydraulic control rather than electronic control, the shift of the 2-3 shift valve is detected, this signal is manually input to the electronic control unit 58, and the predetermined shift is performed from now on. The timing solenoid valve 94 may be switched after a certain period of time.

(G) As described in detail, according to the present invention, after a predetermined period of time after the shift valve is switched and hydraulic pressure begins to be supplied to the oil chamber of one friction element, the timing adjustment valve is switched and the other friction element is switched. Since the oil pressure is supplied to the oil chambers of the elements, the timing at which the oil pressures of the two oil chambers start rising 1γ can be optimally controlled.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing an embodiment of the present invention, FIG. 2 is a diagram showing a skeleton diagram of an automatic transmission, and FIG. 3 is a diagram showing oil pressure rise characteristics according to the present invention. 18... Oil path (hydraulic source oil path), 26.2-3 shift valve (shift valve), 28... Spool, 32...
・Oil passage (first oil passage), 38...Oil passage (second oil passage), 4
(...timing adjustment valve, 42...spool,
58...Electronic control unit, 94...Timing solenoid valve (solenoid), S/R/servo release chamber (oil chamber of second grinding element). H&R/C...High Ant Reverse Clutch (first friction element). Patent Applicant [1Pon Automatic Transmission Co., Ltd. Agent Patent Attorney Toshiyuki Miyauchi t2 Hours

Claims (1)

[Claims] 1. A shift control device for an automatic transmission in which oil pressure is supplied to the oil chambers of two friction elements at a predetermined gear stage, comprising: a shift valve, a timing adjustment valve switched by a solenoid, and an electronic control. It has a unit,
The spool of the shift valve can be switched between a supply position for supplying the hydraulic pressure of the hydraulic source oil passage to the first oil passage and a discharge position for discharging the oil pressure of the first oil passage, and the first oil passage is The spool of the timing adjustment valve is connected to the oil chamber of the first friction element and the timing adjustment valve, and the spool of the timing adjustment valve has a communication position where the first oil passage and the second oil passage communicate with each other, and a communication position where the first oil passage and the second oil passage communicate with each other. The second oil passage is connected to the oil chamber of the second friction element, and the electronic control unit controls the switching of the shift valve. 1. A shift control device for an automatic transmission, characterized in that the shift control device for an automatic transmission is configured to output a switching signal for a timing adjustment valve to a solenoid after a predetermined period of time. 2. The shift control device for an automatic transmission according to claim 1, wherein the predetermined period of time changes depending on the vehicle speed.