JPH01288655A - Device for controlling automatic transmission - Google Patents

Abstract

PURPOSE:To improve the switchover accuracy of selector valves by making both pilot pressure which is regulated by a pilot pressure valve and duty pressure in which the pilot pressure is duty ratio controlled oppositely act on the selector valves. CONSTITUTION:When pilot pressure which is regulated by a pilot pressure valve 48 gets higher than a set value for some reason or other, the duty pressure of a duty pressure oil passage 20 also gets higher. Therefore, oil pressure which acts on the large pressure receiving area portions 12a, 28a and 42a of a 1-2 shift valve 10, a 2-3 shift valve 26, and a 3-2 timing valve 40 gets higher than the set value. However, the pilot pressure of a pilot pressure oil passage 50 which acts on small pressure receiving area portions 12b, 28b and 42b equally gets higher. Hence, the switchover points of the shift valves 10, 26 and timing valve 40 are not affected and determined only by a duty ratio. Thereby, each valve can be switched over as the valve is set.

Description

[Detailed description of the invention] (b) Industrial application fields The present invention relates to a control device for an automatic transmission.

(b) Conventional technology As a conventional automatic transmission control device,
There is one shown in Publication No. 1152. The automatic transmission control device shown therein is configured to control four forward speeds by switching four shift valves using one solenoid valve. That is, the solenoid valve is capable of outputting four levels of oil pressure, and the shift valve is configured to be switched depending on the magnitude relationship between the oil pressure output from the solenoid valve and a spring that applies a pushing force to the spool of the shift valve. The switching characteristics of each shift valve are different from each other. This makes it possible to switch four shift valves using one solenoid valve.

(c) Problems to be Solved by the Invention However, the conventional automatic transmission control device as described above has a problem in that there is variation in the switching granularity of the shift valve. That is, the solenoid valve performs duty ratio control using a constant pilot pressure regulated by the pilot pressure valve, and outputs four levels of hydraulic pressure. However, if the pilot pressure itself, which is regulated by the pilot pressure valve, fluctuates, the duty pressure, which is controlled by the duty ratio, will also fluctuate, and as a result, the switching point of the shift valve, which is switching-controlled, will also fluctuate. The pilot pressure valve is a valve that regulates a constant pressure, or the pressure regulation value fluctuates due to changes in flow rate, etc., or the pilot pressure value fluctuates due to variations in the setting force of the pilot pressure valve spring. become. The accuracy of the switching valve is determined by changes in the sublink load due to the stroke of the switching valve and variations in the set load. The spool of the switching valve normally requires a stroke of 5 to 6 mm to switch the oil path. Therefore, a change in the sublinker occurs before and after the stroke (stroke x spring constant). Also, regarding the set load, it is necessary to allow for a certain ratio of variation by 1F'1-.
The larger the set load, the greater the variation. Therefore,
When setting the duty pressure, it is necessary to take into account the changes and variations in the load mentioned above. When multiple switching valves are controlled by stepped duty pressures output by a single solenoid valve, the difference between the duty pressures is sufficient to compensate for the above-mentioned load changes and variations in the pilot pressure valve and switching valve. Do you need to set it up to be sufficiently secure? - On the other hand, from the point of view of the efficiency of the automatic transmission and the size of the solenoid, it is preferable that the pilot pressure (that is, the maximum duty pressure) is lower. For this reason, it is actually difficult to control three or more switching valves with one solenoid valve. The present invention aims to solve such problems.

(d) Means for Solving the Problems The present invention solves the above problems by causing duty pressure and pilot pressure to act against each other on the spool of the switching valve. That is, the automatic transmission control device according to the present invention includes a switching valve (
10, 26, 40), a solenoid valve (56) that operates according to a given duty ratio signal, and a pilot valve (48) that can output a constant pilot pressure to the pilot pressure oil path (5o). The solenoid valve is capable of adjusting the oil pressure of the duty pressure oil passage (20) connected to the pilot pressure oil passage via the orifice (52) to a state lower than the pilot pressure, and the spool ( 12, 28, 42) are large pressure receiving area portions (12a) that apply opposing forces when hydraulic pressure is applied.
, 28a, 42a) and small pressure receiving area portions (12b, 28b
, 42b), and the duty pressure oil passage is connected to the port (22, 34, 46) that applies hydraulic pressure to the large pressure receiving area of the switching valve, and applies hydraulic pressure to the small pressure receiving area of the switching valve. A pilot pressure oil path is connected to the ports (23, 35, 47). Note that the symbols in parentheses indicate corresponding shrines in the embodiments described later.

(E) The duty pressure adjusted by the solenoid valve acts on the large pressure receiving area portion of the spool of the action switching valve, and the pilot pressure adjusted by the pilot pressure valve acts on the small pressure receiving area portion.

The switching valve is switched depending on the magnitude relationship between the duty pressure and the pilot pressure. The solenoid valve uses the pilot pressure supplied through the orifice as a hydraulic pressure source, and reduces the pressure in accordance with the duty ratio to obtain the duty pressure.

Therefore, when the pilot pressure fluctuates, the duty pressure also fluctuates accordingly, and the self-cutting force acts on the switching valve in accordance with only the duty ratio. That is, even if the pilot pressure fluctuates, the switching point of the switching valve remains as set and will not fluctuate.

By using a plurality of switching valves and setting the ratio of the large pressure receiving area portion and the small pressure receiving area portion of each switching valve to different values, the plurality of switching valves can be controlled by one solenoid valve. I can do it. Further, the switching valve may not be provided with a spring, and may be switched only based on the magnitude relationship between the pilot pressure and the duty pressure. In this case, fluctuation factors such as spring load changes and variations are eliminated, and a decrease in switching accuracy is prevented. Further, a spring may be provided to stabilize the position of the spool when no hydraulic pressure is applied, but in this case, the load of the spring is set to the minimum necessary value. This makes the influence of spring load changes and variations very small and has almost no effect on the switching granularity.

(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 I that transmits the rotational force from the engine output shaft E via a torque converter T/C, an output shaft O that transmits the driving force to the final drive device, a first M star gear set G1, and a second planetary gear set G1. It consists of gear set G2, high reverse clutch H&R/C, forward clutch F/C, hunt brake B, low and reverse brake L&R/B, and one-way clutch OWC. 1st Planetary Gear East Group G] is Sun Gear St, Internal Gear R1, and both Kia S1 and R.
The planetary gear set G2 consists of a carrier PCI that supports a pinion gear P1 that engages with the pinion gear P1 at the same time, and a planetary gear set G2 includes a sun gear S2, an internal gear R2, and both Kia 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 above power transmission mechanism operates the planetary gear set G1 and Each element of G2 (Sl, S2, R1, R2,
It is possible to change the rotational state of the PCI and PO2), thereby making it possible to obtain three forward speeds and one reverse speed by varying the rotational speed of the output shaft 0 relative to the rotational speed of the human power shaft I.

FIG. 1 shows only the parts of the hydraulic circuit that are directly related to the present invention. The 1-2 shift valve 10 includes a spool 12 having a large pressure receiving area portion 12a and a small pressure receiving area portion 12b. The large pressure receiving area 12a has a larger pressure receiving area than the small pressure receiving area 12b. Further, the large pressure receiving area portion 12a and the small pressure receiving area portion 12b are arranged so as to apply opposing forces to the spool 12 when hydraulic pressure is applied. The spool 12 connects the oil passage 16 and the oil passage 18 in the lower half position in the figure, and drains the oil passage 18 in the upper half position in the figure. Spool 1
The position 2 is caused by the hydraulic force acting on the large pressure receiving area portion 12a from the duty pressure oil passage 20 via the port 22, and the oil pressure acting on the small pressure receiving area portion 12b from the pilot pressure oil passage 50 via the port 23. It is determined by the balance of forces. Line pressure is always supplied to the oil passage 16 from the manual valve 24 during forward movement. In addition, oil passage 16
is also connected to the forward clutch F/C.

The 2-3 shift valve 26 includes a spool 28 including a large pressure receiving area portion 28a and a small pressure receiving area portion 28b. The large pressure receiving area portion 28a has a larger pressure receiving area than the small pressure receiving area portion 28b. In addition, the large pressure receiving area part 2
8a and the small pressure receiving area portion 28b are arranged so as to apply opposing forces to the spool 28 when hydraulic pressure is applied. Note that the pressure receiving area of the large pressure receiving area portion 28a of this 2-3 shift valve 26 is larger than that of the 1-2 shift valve 1.
The pressure receiving area of the small pressure receiving area 28b of the 2-3 shift valve 26 is smaller than that of the small pressure receiving area 12b of the 1-2 shift valve 1o. . The spool 28 connects the oil passage 18 and the oil passage 32 at the upper half position in the figure, and trains the oil passage 32 at the lower half position in the figure. The position of the spool 28 is determined by the force due to the hydraulic pressure acting on the large pressure receiving area portion 28a from the duty pressure oil passage 20 via the port 34 and the pilot pressure oil passage 5.
It is determined by the balance with the hydraulic force acting on the small pressure receiving area portion 28b from 0 through the port 35. The oil passage 18 is connected to a servo apply zs7A for engaging the bunt brake B. The oil passage 32 in which the orifice 31 is provided is a high-ant reverse clutch H&
Connected to R/C. In addition, the oil passage 32 is connected to a check valve 36.
It is connected to the oil passage 38 by. The check valve 36 is arranged to allow oil to flow from the oil path 32 side to the oil path 38 side, or to not allow oil to flow in the opposite direction.

The 3-2 timing valve 40 includes a spool 42 having a large pressure receiving area portion 42a and a small pressure receiving area portion 42b. The large pressure receiving area portion 42a is the small pressure receiving area portion 42b.
It has a larger pressure receiving area. Also, this 3-2
The large pressure receiving area portion 42a of the timing valve 40 is 1-2
It has the same pressure receiving area as the large pressure receiving area 12a of the shift valve 10 and the large pressure receiving area 28a of the 2-3 shift valve 26. The pressure receiving area of the small pressure receiving area portion 42b of the 3-2 timing valve 40 is smaller than the pressure receiving area of the small pressure receiving area portion 28b of the 2-3 shift valve 26. The large pressure receiving area portion 42a and the small pressure receiving area portion 42b are arranged so as to apply opposing forces to the spool 42 when hydraulic pressure is applied. The spool 42 communicates the oil passage 32 and the oil passage 38 in the lower half position in the figure, and blocks the oil passage 38 and the oil passage 32 in the upper half position in the figure. The position of the spool 42 is determined by the hydraulic force acting on the large pressure receiving area portion 42a from the duty pressure oil passage 20 via the port 46, and the hydraulic force acting on the small pressure receiving area portion 42b from the pilot pressure oil passage 50 via the port 47. It is determined by the balance between the force and the force. Oil passage 38 is hunt brake B
It is connected to the servo release chamber S/R for releasing. 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 when hydraulic pressure acts on the servo release chamber S/R, the band brake B is necessarily released. Ru.

The above-mentioned duty pressure oil passage 20 is connected to the pilot pressure valve 4
Pilot pressure oil line 5 which is always supplied with constant pressure from 8
0 through an orifice 52. The duty pressure oil passage 20 is provided with an opening 154, and a solenoid valve 56 that can open and close this opening 154 is provided. The solenoid valve 56 is duty ratio controlled by a signal from an electronic control device 58. Thereby, the oil pressure of the duty pressure oil passage 20 can be adjusted to a predetermined oil pressure commanded by the electronic control device 58.

The electronic control device 58 receives electric signals from the vehicle speed sensor 60, throttle opening sensor 62, etc., and based on these, the electronic control device 58 adjusts the oil pressure of the duty pressure oil passage 20 to Pl, P2, P2, etc. Outputs signals for adjustment in four stages, P3 and P4. In addition, the magnitude of the oil pressure is P4 > P3 > P2 > PI Binding-C. On the other hand, the relationship between the large pressure receiving area portion 12a and the small pressure receiving area portion 12b of the spool 12 of the 1-2 shift valve 10 is that when the oil pressure of the port 22 is below PA, the force due to the pilot pressure acting on the small pressure receiving area portion 12b is When the pressure becomes larger, the condition is shown in the lower half of the figure, and conversely, when the oil pressure of the port 22 becomes stronger than the PA, the condition is set in the upper half of the figure. Similarly 2-3 shift valve 2
6 is also set so that when the oil pressure of the port 34 is less than PR, it is in the lower half state in the figure, and when it is greater than PB, it is in the - half state in the figure. Also, regarding the 3-2 timing valve 40, when the hydraulic pressure acting on the port 46 is less than or equal to PC, it is in the state shown in the lower half of the diagram, and when it is greater than PC, it is in the state shown in the upper half of the diagram. It is. The magnitude of the oil pressure at Kowara is P A > P n
> P c. Also, Pl, P2.
P3 and P4, PA, PIi and PC: The relationship between the hydraulic pressures is as follows: P4 >PA >Pal >pH>P2 >PC>PI
This is how it should be. This relationship is illustrated in FIG. 3.

By setting the hydraulic characteristics as described above, shift control and 3-2 shift timing can be adjusted.

First, regarding gear shifting, when the oil pressure of the duty pressure oil passage 20 reaches P4, both the 1-2 shift valve 1° and the 2-3 shift valve 26 are in the state of "-r" in the figure, and the forward I and clutch F Only /C is engaged, resulting in the first speed state. Next, set the oil pressure of the duty pressure oil passage 20 to P2 or P
When l is set to 1, the 1-2 shift valve 10 is in the lower half of the figure, and the 2-3 shift valve 26 is also in the lower half. Therefore, in addition to the forward clutch F/C, hydraulic pressure is also supplied to the surf brake chamber S/A, so that the bunt brake B is engaged, and the automatic transmission is placed in the second speed state. Next, when the oil pressure of the duty pressure oil passage 2o is set to P, the -2 shift valve 1o is in the lower half of the figure, while the 2-3 shift valve 26 is in the upper half of the figure. As a result, High Ant Reverse Clutch H&R/
Hydraulic pressure is supplied to C and servo release chamber S/R, and the third
Becomes a state of speed. In addition, since the check valve 36 is provided, the oil pressure in the oil passage 32 is controlled by the state 7 of the 3-2 timing valve 4o.
It is supplied to the servo release chamber S/R regardless of whether it is connected or not.

Further, the 3-2 timing valve 4o operates as follows. 1- That is, the position of the 3-2 timing valve 40 is switched when the oil pressure of the duty pressure oil passage 2o is P2 and Pl. That is, when the oil pressure P2 is reached, the 3-2 timing valve 40 is in the upper half state, and the oil passage 38 is in the blocked state, and conversely, the oil pressure P2 is the same.

In this case, the oil passage 32 and the oil passage 38 communicate with each other. Utilizing this, for example, the timing of the 3-2 shift can be adjusted as follows. That is, when the oil pressure in the duty pressure oil passage 20 is switched from the state P (ie, 3rd speed) to P2, the 2-3 shift valve 26 is switched to the 2nd gear state (ie, 100%). 7 part state to F half state), while the 3-2 timing valve 40 is -1? I' remains partially in position. Therefore, although the hydraulic pressure of the high angle reverse clutch H&R/C begins to be discharged, the hydraulic pressure of the servo release chamber S/R is not discharged. After maintaining this state for a predetermined time, the oil pressure of the duty pressure oil passage 20 is changed to P.
, to Pl. As a result, the 2-3 shift valve 26 does not remain in the 3I'' partial state, but the 3-2 timing valve 40 switches from the upper half state to the lower half state, and the oil passages 38, 32, etc. As a result, the hydraulic pressure in the servo release chamber S/R also begins to be discharged.In this way, the discharge of the hydraulic pressure in the servo release chamber S/R is delayed by a predetermined period of time compared to the discharge of the hydraulic pressure in the high-ant reverse clutch H&R/C. As a result, the automatic transmission is temporarily placed in a neutral state, and during this time the engine rotational speed is increased, and then the automatic transmission is placed in a 2nd speed state. Since a normal state is inserted and the difference in rotational speed between the engine side and the automatic transmission side is changed at company expense, the speed change is ignored.

As shown in section J, the neutral time inserted during 3-2 gear shifting is controlled by the electronic control unit 58 according to the driving conditions, and is always controlled according to the conditions of vehicle speed and thrower opening degree. Appropriately controlled.

During one of the above operations, the 1-2 shift valve 10.2
-3 shift valve 26 and 3-2 tie valve 40
is always switched at the set switching point. In other words, if the pilot pressure adjusted by the pylon pressure valve 48 or some other reason causes it to be 6 higher than the set I.C, then this high oil pressure is used to increase the solenoid valve 5.
6 or 11, the duty pressure oil passage 20's dubuoy j will be adjusted according to the kneading process. For this reason, 1-2 Nfthalb 10.2-
It becomes higher than the set value of the 3rd half tank 26 and 3-2 tie (hydraulic pressure 71 acting on the 3rd half shaft 40 dog receiving space portions 12a, 28a, and 42a). However, the force opposing the force due to the hydraulic pressure acting on the human pressure receiving surface ridges 12a, 28a, and 42a is the pilot pressure of the pilot oil passage 50 acting on the small pressure receiving surface areas 12b, 28b, and 42b. Therefore, this pilot pressure is affected as well. Therefore, the pressure regulation value of the pilot pressure valve 48 fluctuates and C
Also ■-2 shift valve 10.2-3 shift valve 26
The switching point of the 3-2 timing valve 40 is determined only by the duty ratio without being influenced. This allows each valve to be switched as set.

In addition, in this embodiment, the 1-2 shift valve 10.2-
The 3-shift valves 26 and 3-2 timing valves 40 are switched only by the hydraulic pressure acting on the human pressure-receiving surface ridges 12a, 28a, and 42a and the small pressure-receiving area portions j2b, 28b, and 42b. Since there is no spring provided to apply pressure or force to 42, the cost can be reduced compared to the case where a spring is provided, and there is no influence from variations in the springs.

In addition, 1-2 shift valve 10.2-3 shift valve 2
Of course, it is also possible to provide each spool of the 6 and 3-2 timing valves 40 with a spring that applies a relatively small pushing force. When such a spring is provided, there is an advantage that the spool moves to the required predetermined position when the hydraulic pressure is no longer applied.

(G) As described in detail, according to the present invention, the pilot pressure regulated by the pilot pressure valve and the duty pressure obtained by controlling the duty ratio of the pilot pressure act on the switching valve in opposition to each other. As a result, switching control of the switching valve can be performed based on the duty ratio regardless of variations in pilot pressure, and switching accuracy is improved.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing an embodiment of the present invention, FIG. 2 is a schematic diagram of an automatic transmission, and FIG. 3 is a diagram showing hydraulic characteristics. 10... 1-2 shift valve, 12... spool,
12a...Person pressure receiving surface ridge portion, 12b...Small pressure receiving area portion, 20...Ayuty pressure oil passage, 22...Port, 2
3...Port, 26...2-3 shift valve, 28
...Spool, 28a...Person pressure receiving surface ridge, 28b.
...Small pressure receiving area part, 40...3-2 timing valve, 42...Spool, 42a...Person pressure receiving surface ridge part, 4
2b...Small pressure receiving area part, 46.47...Port, 4
8... Pilot pressure valve, 50... Pilot oil path, 52... Orifice, 56... Solenoid valve.

Claims (1)

[Claims] 1. A switching valve that switches between two positions, a solenoid valve that operates according to a given duty ratio signal, and a pilot valve that can output a constant pilot pressure to a pilot pressure oil path; The solenoid valve can adjust the oil pressure of the duty pressure oil path connected through the pilot pressure oil path and the orifice to a state lower than the pilot pressure, and the spool of the switching valve It has a large pressure receiving area section and a small pressure receiving area section that apply forces in opposing directions to each other, and a duty pressure oil passage is connected to a port that applies hydraulic pressure to the large pressure receiving area section of the switching valve. A control device for an automatic transmission in which a pilot pressure oil path is connected to a port that applies hydraulic pressure to a pressure receiving area. 2. The control device for an automatic transmission according to claim 1, wherein a plurality of switching valves are provided. 3. The control device for an automatic transmission according to claim 1 or 2, wherein the switching valve does not have a spring that applies a pushing force to the spool. 4. The control device for an automatic transmission according to claim 1 or 2, wherein the switching valve has a spring that applies a pushing force to the spool.