JPH0570028B2 - - Google Patents

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 Japanese Patent Application Laid-open No. 101152/1983. The automatic transmission shift control device shown in this figure 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 switching characteristics of the shift valves are set so that one shift valve is switched for each step change in the oil pressure. This makes it possible to switch four shift valves using one solenoid valve.

On the other hand, Japanese Unexamined Patent Publication No. 62-62047 discloses a system using a total of three solenoid valves for speed change control. That is, two solenoid valves are used for switching the shift valve, and the remaining one solenoid valve controls the overrun clutch control valve. The overrun clutch control valve controls the engagement and release of an overrun clutch that switches between applying and deactivating the engine brake.
This makes it possible to select between a state in which the engine brake is applied and a state in which it is not applied between the first and third speeds, and a state where the engine brake is always ineffective in the fourth speed.

(c) Problems to be solved by the invention When the latter prior art is applied to the former prior art, the shift valve is switched by one solenoid valve, and the overrun clutch control valve is switched by one solenoid valve. This means that only two solenoid valves are required in total. However, in this case, it is necessary to control the shift between the four speeds using four or more levels of signal oil pressure generated by one solenoid valve, and the difference between the signal oil pressures at each level becomes small. Since it is necessary to identify the switching accuracy, the reliability of switching accuracy decreases. In particular, with regard to the conventional example described above, if the overrun clutch is erroneously engaged in the fourth gear, an interlock condition may occur and the automatic transmission may be damaged. Therefore, in the fourth gear, it is necessary to ensure that the overrun clutch is not engaged. The present invention aims to solve such problems.

(d) Means for Solving the Problems In the present invention, the shift valve and the overrun clutch control valve are controlled by the same solenoid valve, so that the overrun clutch is always released at a gear position where an interlock occurs. By doing so, the above problem is solved. That is, the shift control device for an automatic transmission according to the present invention prevents engine braking from occurring at speeds other than the m-th speed (first, second, and third speeds) by engaging the overrun clutch 24 provided in parallel with the one-way clutch 30. It becomes possible, but mth speed (4th speed)
This is intended for a shift control device of an automatic transmission that enters an interlock state when the overrun clutch 24 is engaged, and switches between a first position and a second position by a switching signal pressure. A first shift valve 70 that controls switching between the m-th gear and a gear other than the m-th gear, and one or more other shift valves 110, 126 that switches between gears other than the m-th gear according to a switching signal pressure. an overrun clutch control valve 40 that controls the supply and discharge of hydraulic pressure to the overrun clutch 24 by switching between a first position and a second position;
A first solenoid valve 80 outputs to the shift valve 70 and the overrun clutch control valve 40.
and another solenoid valve 56 that performs switching control of the other shift valves 110 and 126; and an electronic control device 58 that provides electrical signals to the first solenoid valve 80 and the other solenoid valve 56. The switching signal pressure for switching the overrun clutch control valve 40 between the first position and the second position is
The present invention is characterized in that the shift valve 70 is set to a value that maintains a state in which the shift valve 70 is switched to a position where a gear stage other than the m-th gear is obtained.

(E) Operation The overrun clutch control valve is switched between the first position and the second position by a switching signal pressure from the first solenoid valve. The switching signal pressure at this time is set to a value that maintains the state in which the first shift valve is switched to a position where a gear stage other than the m-th gear is obtained. Therefore, the overrun clutch control valve does not switch to the overrun clutch engagement side at the m-th speed, and an interlock condition is reliably prevented from occurring.

(F) Embodiments Examples of the present invention will be described below with reference to FIGS. 1 to 5 of the accompanying drawings.

Figure 2 shows 4 forward speeds and 1 reverse speed with overdrive.
The power transmission mechanism of the automatic transmission is shown as a skeleton diagram. This power transmission mechanism includes a torque converter 10
an input shaft 13 to which the rotational force from the engine output shaft 12 is transmitted, an output shaft 14 to transmit the driving force to the final drive device, a first planetary gear set 15,
It has a second planetary gear set 16, a reverse clutch 18, a high clutch 20, a forward clutch 22, an overrun clutch 24, a low and reverse brake 26, a band brake 28, a row one-way clutch 29, and a forward one-way clutch 30. In addition, the torque converter 10
has a built-in lock-up clutch 11. The first planetary gear set 15 includes a sun gear S1, an internal gear R1, and a carrier PC that supports a pinion gear P1 that meshes with both gears S1 and R1 simultaneously.
1, and a planetary gear set 16
are Sun Gear S2, Internal Gear R2,
It is composed of 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 through a high clutch 20, and the sun gear S1 can be connected to the input shaft 1 through a reverse clutch 18.
Can be connected with 3. The carrier PC1 is connected to an internal gear R2 via a forward clutch 22 and a forward one-way clutch 30 connected in series thereto, or via an overrun clutch 24 arranged in parallel to the forward clutch 22 and forward one-way clutch 30. It is possible to connect both. Sun gear S2 is always connected to input shaft 13, and internal gear R1 and carrier PC2 are always connected to output shaft 14.
Low and reverse brake 26 is Carrier PC
1 can be fixed, and the band brake 28 can also fix the carrier S1. Row one way clutch 29 is a carrier
The PC 1 is arranged in an orientation that allows normal rotation (rotation in the same direction as the engine output shaft 12) but does not allow reverse rotation (rotation in the opposite direction to the normal rotation).

The power transmission mechanism includes clutches 18, 20, 2
2 and 24 and brakes 26 and 28 in various combinations, the planetary gear set 15
and each of the 16 elements (S1, S2, R1, R2,
The rotational state of PC1 and PC2) can be changed, thereby making it possible to variously change the rotational speed of the output shaft 14 relative to the rotational speed of the input shaft 13. By operating the clutches 18, 20, 22 and 24 and the brakes 26 and 28 in combination as shown in FIG. 3, four forward speeds and one reverse speed can be obtained. Note that the ○ marks in Figure 3 indicate operating clutches and brakes, α1 and α2.
are the ratios of the number of teeth of sun gears S1 and S2 to the number of teeth of internal gears R1 and R2, respectively, and the gear ratio is the ratio of the number of rotations of input shaft 13 to the number of rotations of output shaft 14.

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

The 1-2 shift valve 110 is composed of a spool 112 and a spring 114, and when the spool 112 is in the lower half position in the figure, the oil passage 116 and the oil passage 118 are communicated with each other, and when the spool 112 is in the upper half position in the figure, the oil passage 1
Drain 18. The position of the spool 112 is determined by the balance between the hydraulic force acting on the port 122 from the oil passage 120 and the force exerted by the spring 114. Line pressure is always supplied to the oil passage 116 from the manual valve 124 during forward movement. Note that the oil passage 116 is connected to the forward clutch 2.
2 and an overrun clutch control valve 40.

The 2-3 shift valve 126 is composed of a spool 128 and a spring 130, and when the spool 128 is in the upper half position in the figure, the oil passage 118 and the oil passage 32 are communicated with each other, and when the spool 128 is in the lower half position in the figure, it communicates with the oil passage 32.
Drain 2. The state of the spool 128 is determined by the oil pressure acting on the port 34 from the oil passage 120. The oil passage 118 is connected to the second speed apply chamber 2A for engaging the band brake 28. Oil passage 3 provided with orifice 31
2 is connected to a third speed release chamber 3R for releasing the high clutch 20 and band brake 28.

The 3-4 shift valve 70 is composed of a spool 71 and a spring 72, and the spool 7
1 connects the oil passage 118 and the oil passage 74 at the lower half position in the figure, and drains the oil passage 74 at the upper half position in the figure. The state of the spool 71 is determined by the oil pressure applied from the oil passage 75 to the port 76. The oil passage 74 is connected to the fourth speed apply chamber 4A in which the band brake 28 is engaged.

The overrun clutch control valve 40 is composed of a spool 42 and a spring 44, and when the spool 42 is in the upper half position in the figure, the oil passage 77
The oil passage 116 communicates with the oil passage 116, and the oil passage 77 is drained at the lower half position in the figure. The position of the spool 42 is determined by the oil pressure acting on the port 46 from the oil passage 75. The oil passage 77 is connected to the overrun clutch 24.

The aforementioned oil passage 120 is connected to the pilot pressure valve 48.
It is connected via an orifice 52 to an oil passage 50 to which a constant pressure is always supplied from. Oil road 120
is provided with an opening 54, and a solenoid valve 56 that can open and close this opening 54 is provided. The duty ratio of the solenoid valve 56 is controlled by a signal from an electronic control device 58. Thereby, the oil pressure in the oil passage 120 can be adjusted to a predetermined oil pressure commanded by the electronic control device 58.

Further, the aforementioned oil passage 75 is connected via an orifice 78 to an oil passage 50 to which a constant pressure is always supplied from the pilot pressure valve 48. Oil road 7
5 is provided with an opening 79, and this opening 79
A solenoid valve 80 that can be opened and closed is provided. The solenoid valve 80 is an electronic control device 58
The duty ratio is controlled by the signal from. Thereby, the oil pressure in the oil passage 75 can be adjusted to a predetermined oil pressure commanded by the electronic control device 58.

Electric signals from a vehicle speed sensor 60, a throttle opening sensor 62, etc. are input to the electronic control device 58, and the electronic control device 58 adjusts the oil pressure in the oil passage 75 to P ₁ , P ₂ , and P ₃ based on these signals. Outputs a signal for adjustment in three stages. Furthermore, the magnitude of the hydraulic pressure is
P ₃ > P ₂ > P ₁ . . On the other hand, the 3-4 shift valve 70 is set so that when the oil pressure of the port 76 is below P _B , it is in the state shown in the lower half of the figure, and when it is greater than P _B , it is in the state shown in the upper half of the figure. be. Similarly, the overrun clutch control valve 40 is set so that when the oil pressure of the port 46 is less than P _A , it will be in the lower half of the figure, and when it is greater than P _A , it will be in the upper half of the figure. be. The magnitude of these oil pressures is set so that P _A > P _B.
Further, the relationship between the hydraulic pressures P ₁ , P ₂ and P ₃ and the hydraulic pressures P _A and P _B is such that P ₃ >P _A >P ₂ >P _B >P ₁ . This relationship is illustrated in FIG. 4.

Similarly, the operation of the solenoid valve 56 is controlled by a signal from the electronic control device 58, and the oil passage 1
The oil pressure of 20 is controlled in three stages: P ₄ , P ₅ and P ₆ (P ₄ <P ₅ <P ₆ ). Also 1-2 shift valve 110
and the switching pressure P _C of the 2-3 shift valve 126 and
P _D is set as shown in FIG.

By setting the hydraulic characteristics as described above,
Shift control and control of the overhang latch 24 can be performed.

First, regarding gear shifting, the oil pressure in the oil passage 75 is P ₂
Or, when the oil pressure in the oil passage 120 reaches P ₆ in the state of P ₃ (that is, the state of the 3-4 shift valve 70 in the upper half), both the 1-2 shift valve 110 and the 2-3 shift valve 126 shift. The state shown in the upper half of the figure is reached, and only the forward clutch 22 is engaged, resulting in the first speed state. Next, when the oil pressure in the oil passage 120 is set to P ₄ , the 1-2 shift valve 110 becomes the state shown in the lower half of the figure, and the 2-3 shift valve 12
6 is also in the lower half state. Therefore, in addition to the forward clutch 22, hydraulic pressure is supplied to the second speed apply chamber 2A, and the band brake 28 is engaged, so that the automatic transmission enters the second speed state. Next, oil path 1
When the oil pressure of 20 is set to _P5 , the 1-2 shift valve 110 is in the lower half of the figure, while the 2-3 shift valve 126 is in the upper half of the figure. As a result, hydraulic pressure is supplied to the high clutch 20 and the third speed release chamber 3R, resulting in the third speed state. Next, when the oil pressure in the oil passage 75 is set to _P1 , the 3-4 shift valve 70 is switched to the upper half position. As a result, the 4th speed apply chamber 4 of the band brake 28
Hydraulic pressure is supplied to A, resulting in the fourth speed state.

The overrun clutch control valve 40 also operates as follows. In other words, the oil pressure in the oil passage 75 is
If P ₂ or P ₃ , 3 in any case
The -4 shift valve 70 is in the third gear position, but the position of the overrun clutch control valve 40 switches between oil pressure _P2 and oil pressure _P3 . At oil pressure P ₃ , the overrun clutch control valve 40 is in the upper half position and oil pressure is supplied to the overrun clutch 24 . Therefore, the overrun clutch 24 is engaged, and engine braking can be utilized in the first to third speeds. On the other hand, at oil pressure P ₂ , the overrun clutch control valve 40 is in the lower half position,
No oil pressure is supplied to the overrun clutch 24.
Therefore, overrun clutch 24 is in a released state and engine braking is not available.

As described above, the solenoid valve 56 controls the 1-2 speed shift and the 2-3 speed shift, and the solenoid valve 80 controls the 3-4 speed shift and switching of the overrun clutch control valve 40. Each of the solenoid valves 56 and 80 only needs to output three levels of oil pressure, which improves the accuracy of oil pressure identification. In other words, for example, if one solenoid valve outputs four levels of oil pressure, the difference in oil pressure between each level will be small, and if there are large variations in the setting force of the shift valve spring, errors may occur. It may work. If the hydraulic pressure is set to three levels, the pressure difference between each level will become larger, and the reliability will improve accordingly.

Further, as can be seen from FIG. 4, when the 3-4 shift valve 70 is in the 4th gear position, the overrun clutch control valve 40 is switched to the overrun clutch 24 position.
Become a liberator. Therefore, interlock conditions are reliably prevented from occurring.

(G) Effects of the Invention As explained above, according to the present invention, the switching signal pressure for switching the overrun clutch control valve between the first position and the second position is applied when the first shift valve is at a speed other than the m-th speed. Since the value is set to maintain the state of switching to the position where the gear position is obtained, it is possible to reliably prevent the occurrence of a problem such as when the overrun clutch is engaged at the m-th speed and an interlock state occurs.

[Brief explanation of the drawing]

Fig. 1 is a diagram showing an embodiment of the present invention, Fig. 2 is a skeleton diagram of an automatic transmission, Fig. 3 is a diagram showing a combination of elements that operate at each gear stage, and Figs. 4 and 5 are diagrams of the present invention. FIG. 3 is a diagram showing the hydraulic characteristics of the invention. 110...1-2 shift valve, 126...2-3
Shift valve, 40... Overrun clutch control valve, 56... Solenoid valve, 58... Electronic control device, 70... 3-4 shift valve, 80... Solenoid valve.

Claims (1)

[Claims] 1. By engaging the overrun clutch 24 provided in parallel with the one-way clutch 30, engine braking becomes possible at speeds other than the m-th speed, but the overrun clutch 24 is engaged at the m-th speed. In the shift control device of the automatic transmission which enters an interlock state in such a case, the shift control device of the automatic transmission switches between the first position and the second position according to the switching signal pressure, and controls the switching between the m-th speed and the other gears. a first shift valve 70 that switches between the first and second positions according to a switching signal pressure; An overrun clutch control valve 40 that controls the supply and discharge of hydraulic pressure to the overrun clutch 24, and a switching signal pressure that controls the first switching signal pressure in response to an applied electric signal.
A first solenoid valve 80 outputs to the shift valve 70 and the overrun clutch control valve 40.
and another solenoid valve 56 that performs switching control of the other shift valves 110 and 126; and an electronic control device 58 that provides electrical signals to the first solenoid valve 80 and the other solenoid valve 56. , the switching signal pressure for switching the overrun clutch control valve 40 between the first position and the second position is
A shift control device for an automatic transmission, characterized in that the shift valve 70 is set to a value that maintains a state in which the shift valve 70 is switched to a position for obtaining a gear stage other than the m-th gear.