JPS62389B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a lock-up control circuit for a lock-up automatic transmission, and more particularly, to a lock-up control circuit for a lock-up automatic transmission in which the lock-up state can be released by decelerating the vehicle. It is something.

Generally, automatic transmissions include a torque converter in the power transmission system for the purpose of absorbing torque fluctuations from the engine and increasing the torque from the engine. The torque converter uses an input element (usually a pump impeller) driven by the engine to rotate the internal hydraulic oil, and this hydraulic oil causes the output element (usually a turbine runner) to rotate under the reaction force of the stator.
is rotated while increasing the torque (converter state). Therefore, in a torque converter, the input and output elements are not mechanically coupled, and slippage between the input and output elements is inevitable.As a result, although automatic transmissions are easy to operate, they have poor power transmission efficiency. Therefore, in relatively high vehicle speed ranges where a torque increase function is not required and torque fluctuations from the engine are not a problem,
A torque converter with a direct coupling clutch (also called a lock-up torque converter) was proposed, in which the input and output elements are directly connected by the operation of a direct coupling clutch (lock-up state), and some lock-up automatic transmissions equipped with this type of torque converter are now available. It is used in many vehicles.

By the way, for example, the lock-up region of an automatic transmission that puts the torque converter with a direct coupling clutch into the lock-up state during high-speed driving where the vehicle speed exceeds the set vehicle speed (lock-up vehicle speed) for each shift position (sometimes only at a specific shift position) is, for example. As shown in Figure 1. This figure shows a shift pattern in a three-speed forward automatic transmission, where V ₁ , V ₂ , and V ₃ are the first
Lock-up vehicle speed for speed, 2nd gear, and 3rd gear.
A, B, and C are respectively 1→2 upshift lines and 2→
1st gear, 2nd gear based on the 3 upshift line,
This is the lock-up area for third gear. In addition, the lock-up release vehicle speeds v ₁ , v ₂ , v ₃ in the first, second, and third gears when the vehicle speed V a decreases are normally the same as when the vehicle speed _{V a increases} , as shown in FIG. The lockup vehicle speeds V ₁ , V ₂ , and V ₃ have small values with hysteresis ΔV. In addition, in Figure 1, 2→1
The lockup region relative to the downshift line and the 3→1 downshift line has been omitted for clarity of illustration.

In this way, the lock-up control is performed depending on the presence or absence of the electrical lock-up signal, that is, the torque converter is put into the lock-up state by the output of the lock-up signal while driving in the above-mentioned lock-up areas A, B, or C; Conventionally, a lock-up control circuit that puts the torque converter in a converter state when the lock-up signal disappears while the vehicle is running has a configuration as shown in the block diagram of FIG. Note that, for convenience, the lock-up control at one shift position will be described below.

35 is a wheel, and 36 is a sensor that detects the rotation speed of the wheel 35. This sensor 36 is coupled to a transducer 37 which is connected to the sensor 36.
converts the signal outputted by the vehicle into a signal V _s corresponding to the vehicle speed. 38 is a comparator, and this comparator 38 is 2
It has two input terminals 38a, 38b and an output terminal 38c. One input terminal 38 of the comparator 38
The output signal v _s of the converter 37 is input to a,
As shown in FIG. 3, the other input terminal 38b is connected in advance to a signal V _t corresponding to the lock-up set vehicle speed V (this V _t is V ₁ in the first gear and V 1 in the second gear).
V ₂ and V ₃ in the third gear) are input, and when the vehicle speed v _a exceeds V, _a signal v _t (this v _t is v ₁ in 1st gear, and v 1 in 2nd gear.
(takes values corresponding to v ₂ and v ₃ up to third speed, respectively) are input. The comparator 38 is connected to the drive circuit 39, and the signal Sc output from the comparator 38 is
When the signal v _s output from the converter 37 becomes equal to or higher than the signal V _t corresponding to the lock-up vehicle speed V, it outputs a lock-up signal having a value of 1, for example, to the drive circuit 39, and then the signal v _s When the lockup signal becomes equal to or less than the signal value _Vt corresponding to the lockup release vehicle speed v, the lockup signal becomes "0". While the lock-up signal "1" is being input, the drive circuit 39 energizes the lock-up solenoid 31 to switch a lock-up control valve (not shown) and place the torque converter in the lock-up state.

However, in such a conventional lock-up control circuit, when the _vehicle is suddenly braked as shown in FIG. ₄ , the comparator 38 is Although the lock-up signal disappears, at the time _t2 when the lock-up state L of the torque converter is actually released, a time delay Δt, that is, ( _t2 - _t1 ) occurs due to the operation delay of the mechanical system and hydraulic system, and the lock-up signal disappears. Before the release is released, the vehicle speed v _a reaches the vehicle speed V _d at which the engine stalls, and the engine stalls. This kind of engine stalling is not only caused by the engine stopping, but also because modern vehicles are equipped with brakes that are boosted by negative pressure in the engine intake, and power steering devices that are operated by oil from the engine-driven pump. However, there were problems with the brakes and steering suddenly becoming heavy. In order to solve this problem, it may be possible to set the lock-up release vehicle speed to a higher speed, but in that case, the time the torque converter remains in the lock-up state will be shortened, and fuel efficiency during steady driving will deteriorate. Resulting in.

The present invention has been made by focusing on such conventional problems, and has a plurality of lock-up release vehicle speeds, and when the deceleration exceeds a set value, selects and outputs a signal corresponding to the lock-up release vehicle speed on the high-speed side,
The purpose of this invention is to solve the above-mentioned problem by configuring a control circuit so as to output a lock-up release signal when a vehicle speed signal corresponding to the vehicle speed becomes less than this output signal.

The present invention will be explained below based on the drawings.

First, an outline of the lock-up torque converter will be explained according to FIG.

The pump wheel 3 of the torque converter 1 is connected via a converter cover 6 to a drive plate 5, which in turn is connected to the engine crankshaft 4. Further, the turbine wheel 8 is splined to the input shaft 7 via a hub 18, and the stator wheel 9 is further connected to the sleeve 12 via a one-way clutch 10. The torque converter 1 is surrounded by a converter housing 28, and the converter housing is connected to the transmission case 29 with the pump housing 1.
4 and pump cover 11. The oil pump 13 is housed in a chamber defined by the pump housing 14 and the pump cover 11, and is coupled to the pump impeller 3 via a hollow shaft 52 so as to be driven by an engine. Hollow shaft 52
The sleeve 12 is wrapped around the sleeve 12 to define an annular hydraulic oil supply passage 50 between the two, and the input shaft 7 is loosely passed through the sleeve 12 to define an annular hydraulic oil discharge passage 51 between the two. . Note that the sleeve 12 is integrally molded with the pump cover 11.

The lockup mechanism 17 has the following configuration. A lock-up clutch piston 20 is slidably fitted onto the hub 18 and is housed within the converter cover 6. An annular clutch facing 19 is provided on the surface of the lock-up clutch piston 20 facing the end wall of the converter cover 6, and when this clutch facing contacts the end wall of the converter cover 6, a lock-up chamber is formed on both sides of the lock-up clutch piston 20. 2
7 and a torque converter chamber 63 are defined.

A lock-up clutch piston 20 is drivingly coupled to the turbine wheel 8 via a torsional damper 21. The torsional damper 21 is of a type used in dry clutches, etc., and the drive plate 23 and torsional spring 24 are composed of a rivet 25 and a driven plate 26. An annular member 22 is attached to the lock-up clutch piston 20.
Weld the claw 22a to the drive plate 23
The driven plate 26 is connected to the turbine wheel 8 by driving engagement with the notch 23a of the notch 23a. The lockup chamber 27 is communicated with a lockup passage 16 formed in the input shaft 7, and this passage is connected to a lockup control valve 30 as described below.

The lock-up control valve 30 includes a spool 30a which, when moved by a spring 30b to the position shown in the upper half of FIG.
When the oil pressure inside the port is set to the lower half position, the port 30d
It functions to allow the drain port 30f to communicate with the drain port 30f. The port 30d communicates with the lockup chamber 27 via the passage 56 and the lockup passage 16;
Port 30e is connected to torque converter chamber 6 via passage 57 and torque converter hydraulic oil supply passage 50.
3, and the chamber 30c communicates with a rear clutch (forward clutch), not shown, through a passage 53.

An orifice 54 is provided in the middle of the passage 53, and a branch passage 55 is provided in the passage 53 between this orifice and the chamber 30c. The branch passage 55 has an orifice 58 therein and a drain port 5.
9, and the lock-up solenoid 31 is used to open and close the branch passage 55. For this purpose, the lock-up solenoid 31 is connected to the plunger 3.
1a, and this plunger is normally kept at the left half position in FIG. 5, but when the solenoid 31 is energized, it is brought to the right half protruding position so that the branch passage 55 can be closed.

When the plunger 31a opens the branch passage 55 due to deenergization of the solenoid 31, this branch passage communicates with the drain port 59. At this time, the rear clutch pressure directed to the chamber 30c via the passage 53 is extracted from the drain port 59, and the lock-up control valve 30 is operated to connect the port 30d to the port 30d because the spool 30a is set to the upper half position in FIG. 5 by the spring 30b. 3
Pass it to 0e. Therefore, the internal pressure of the torque converter led to the passage 57 is transferred to the ports 30e and 30e.
0d, lockup room 27 via passages 56 and 16
The lockup chamber 27 has the same pressure as the converter chamber 63. As a result, the lock-up clutch piston 20 is moved to the right from the position shown in FIG. 1 can perform normal power transmission in the torque converter state.

When the plunger 31a closes the branch passage 55 due to the activation of the lock-up solenoid 31, the passage 53
As the spool 30a moves left from the upper half position to the lower half position in FIG. 5, the lock-up control valve 30 connects the port 30d to the drain port. 3
Connect to 0f. As a result, lockup room 2
7 is lockup passage 16, passage 56, port 3
It communicates with the drain port 30f via 0d and is brought into a pressureless state. Thus, the lock-up clutch piston 20 is moved to the left in FIG.
By being pressed against the end wall of the pump impeller 3 and the turbine runner 8, a locked-up state is obtained in which the pump impeller 3 and the turbine runner 8 are directly connected.

The reference numeral 40 indicates a control circuit for controlling the lock-up solenoid 31, and the reference numeral 39 indicates a drive circuit for the lock-up solenoid 31. Details of the control circuit 40 according to the present invention will be explained below with reference to the block diagram of FIG. Note that the same parts as those of the conventional control circuit shown in FIG. 2 are given the same numbers, and the explanation thereof will be omitted.

Reference numeral 41 denotes a differentiating circuit, to which a signal V _s corresponding to the vehicle speed V _a outputted from the converter 37 described above is input, and this signal V _s is differentiated to obtain an acceleration signal V _s ′. The signal value v _s ' is outputted to one input terminal 42a of the comparator 42. The other input terminal 42b of the comparator 42 receives set deceleration signals b ₁ , corresponding to two preset set decelerations.
b Either one of ₂ is input. These set deceleration signals b ₁ and b ₂ have hysteresis characteristics to prevent hunting, and the set deceleration signal b ₁ is input to the comparator 42 in advance, and as shown in FIG. The speed v _s ′ is the set deceleration signal b ₁
That's all. That is, during sudden braking where the deceleration is higher than a predetermined deceleration, the output signal _s a of the comparator 42
is switched from "1" to "0" and the set deceleration signal b ₂ is input to the input terminal 42b of the comparator 42 instead of the set deceleration signal b ₁ . After this, the deceleration v _s ' decreases and becomes less than the set deceleration b ₂ , that is, in the case of slow braking or non-braking in which the deceleration is less than the predetermined deceleration, the output signal S _a of the comparator 42 becomes "0". ” to “1” and the set deceleration signal b ₁ is input to the input terminal 42 b of the comparator 42 instead of the set deceleration signal b ₂ .

Note that, as is clear from the figure, the set deceleration signal _b2 usually has a larger value than the set deceleration signal _b1 . 45 is the input terminal 38b of the comparator 38
This is a switching circuit connected to the This switching circuit 45
are the signals V _t , v corresponding to the lock-up vehicle speed V and the two lock-up release vehicle speeds v ₁ , v ₂ , respectively.
_x , v _y are input, and when the vehicle reaches a lock-up vehicle speed V or higher, a signal V _t corresponding to this vehicle speed is input.
is output to the comparator 38, and when the vehicle is decelerated to a lock-up release vehicle speed v ₁ or less by gentle braking, a signal v _x corresponding to this vehicle speed is output, and by sudden braking the vehicle is decelerated to a lock-up release vehicle speed v ₂ or less. , a signal v _y corresponding to this vehicle speed is output. That is, the output signal of the comparator 42 is inputted to this switching circuit 45, and in the event of sudden braking, the comparator 42 outputs a signal of "0" and the lock-up release speed signal outputted from the switching circuit 45 becomes v. The _comparator 42 outputs a signal of "1 _" so that the lockup release speed becomes _v1 at other times. These converter 37, differentiation circuit 41, comparators 38, 42 and switching circuit 45
A control circuit 44 is configured. Therefore, as described above, the drive circuit 39 energizes the lock-up solenoid 31 only while the control circuit 44 is outputting the drive signal of "1".

Next, the effect will be explained. Such a control circuit 4
4 has an effect as shown in FIG.
In the figure, the curve V _s is the vehicle speed signal output from the converter 37, the two-dot chain line V is the lock-up vehicle speed, and the two-dot chain line is the vehicle speed signal output by the converter 37.
vy and vx are the lock-up release vehicle speed signal on the high-speed side and the lock-up release vehicle speed signal on the low-speed side, respectively, the two-dot chain line Vd is the vehicle speed at which the engine stalls in the lock-up state, and Va′ is the vehicle deceleration signal output from the differentiator circuit 41 (in this implementation In the example, wheel angular deceleration), two-dot chain line
b ₁ and b ₂ are the aforementioned set deceleration signals, Sc and Sa are lines indicating the signals output by the comparator 38 and comparator 42 as binary values of "1" and "0", respectively, and L is the mechanism and hydraulic system. This shows the actual lock-up state of the Turkish converter 1, including the delay in operation. Note that, for convenience, the shift position is not specified.

As is clear from this figure, if the vehicle VA is traveling normally at a certain speed higher than the lock-up set vehicle speed V, the signals output from the comparators 38 and 42 are
Since Sc and Sa both have a value of "1" and the signal output to the drive circuit 39 also has a value of "1", the drive circuit 39 locks up the solenoid 31.
energize and excite. Therefore, as described above, the plunger 31a closes the branch passage 55, the rear clutch pressure is supplied from the passage 53 into the chamber 30c, and the lock-up control valve 30 closes the branch passage 55.
is moved leftward from the upper half position to the lower half position in FIG. 5, thereby communicating the port 30d with the drain port 30f. Thereby, the lockup chamber 27 communicates with the drain port 30f via the lockup passage 16, the passage 56, and the port 30d. Therefore, the lock-up clutch piston 20 is connected to the converter chamber 6.
Due to the internal pressure of the torque converter 3, the clutch facing 19 is moved to the left in FIG.
is pressed against the end wall of the converter cover 6, thereby connecting the pump impeller 3 and the turbine runner 8, and the torque converter 1 is placed in a locked-up state.

On the other hand, if the vehicle enters the braking state from this state,
First, during sudden braking, deceleration occurs before the vehicle speed va reaches the low-speed rotaup release vehicle speed v ₁ .
va' reaches the set deceleration corresponding to the set deceleration signal _b1 . Furthermore, since the switching circuit 45 is decelerating, it outputs the lock-up release vehicle speed signal _v1 to the output terminal 38a of the comparator 38, but the deceleration signal
When va′ becomes less than the set deceleration signal b ₁ , comparator 4
2 outputs to the switching circuit 45 as a signal of "0", and the switching circuit 45 switches the output signal to the lock-up release vehicle speed signal vy on the high speed side. Therefore, the signal that the comparator 38 outputs to the drive circuit 39
Sc takes a value of "0" when the vehicle speed signal VS reaches the lockup release speed signal vy on the high speed side, and the drive circuit 39 stops energizing the lockup solenoid 31. Therefore, the plunger 31a is connected to the branch passage 5.
5 is opened, the branch passage 55 communicates with the drain port 59. At this time, the rear clutch pressure directed to the chamber 30c via the passage 58 is extracted from the drain port 59, and the lock-up control valve 30 is moved from the port 30d to the port 30d because the spool 30a is set to the upper half position in FIG. 5 by the spring 30b. 30e. Therefore, the internal pressure of the torque converter led to the passage 57 passes through the port 30e, the port 30d, the passage 56, and the passage 16 to the lockup chambers 27, 27.
The lockup chamber 27 has the same pressure as the converter chamber 63. As a result, the lock-up clutch piston 20 is moved to the right from the position shown in FIG. Converter 1 comes to perform normal power transmission in the converter state.

When this actual lockup state L is released,
As shown in FIG. 7, the engine does not stall because the vehicle speed has not yet reached the vehicle speed Vd at which the engine stalls.
In other words, the actual lock-up release including the delay in the operation of the mechanical system and hydraulic system is as shown by the straight line L in the figure, when the vehicle speed Va changes to the vehicle speed Vd at which the engine stalls.
It will be done before reaching . Furthermore, when returning to normal running, if the deceleration signal va' becomes small to the set deceleration signal _b2 , the comparator 42 outputs a signal of "1" to the switching circuit 45, so the switching circuit 45 Low speed side lockup release signal vx
Output. Therefore, although lock-up release is delayed compared to the sudden braking, since the deceleration is small, there is sufficient time until the vehicle speed reaches Vd at which the engine stalls, and there is no risk of the engine stalling. This allows for longer lock-up time and improves fuel efficiency.

Although the deceleration of the vehicle is detected from the wheels in the above embodiment, it may be detected from the speedometer or the G.
Needless to say, you can use things like balls.

As explained above, according to this invention,
In the control circuit of a lock-up type automatic transmission, the torque converter is placed in a lock-up state where the input and output are directly connected when the vehicle speed exceeds the lock-up vehicle speed at each shift position, and the converter is placed in the converter state when the vehicle speed falls below the lock-up release vehicle speed. and a plurality of lock-up release vehicle speeds, and when the deceleration exceeds a set value, selects and outputs a signal corresponding to the lock-up release vehicle speed on the high-speed side;
Since the lock-up release signal switching circuit is equipped with a lock-up release signal switching circuit that outputs a lock-up release signal when the vehicle speed signal corresponding to the vehicle speed falls below this output signal, the lock-up time when not braking or during slow braking is lengthened to improve fuel efficiency. However, even when the vehicle is suddenly braked, the engine stall of the vehicle is prevented, and steering and brake malfunctions caused by the engine stall can be prevented. Furthermore, when a lock-up release signal is issued when the deceleration drops below a set value, lock-up activation and lock-up release are repeated due to the influence of uneven road surfaces, etc., which tends to cause hunting. However, in the present invention, this can be avoided by switching the lock-up release vehicle speed. performs the function of hysteresis,
Hunting can be easily prevented.

[Brief explanation of the drawing]

Fig. 1 is a shift pattern diagram of an automatic transmission illustrating the lock-up region of the torque converter;
The figure is a block diagram showing the lock-up control circuit of a conventional lock-up type automatic transmission. Figure 3 shows the relationship between vehicle speed, lock-up vehicle speed, and lock-up release vehicle speed, and sets the output of the comparator to "1".
FIG. 4 is a diagram showing the operation of the conventional lock-up control circuit shown in FIG. 2 in relation to vehicle speed, and FIG. 5 is a diagram showing the mechanism of the lock-up torque converter according to the present invention. FIG. 6 is a cross-sectional view, and FIG. 6 is a block diagram showing a control circuit of a lock-up automatic transmission according to an embodiment of the present invention.
This figure is a diagram showing the operation of the control circuit shown in FIG. 6 in relation to vehicle speed and deceleration. DESCRIPTION OF SYMBOLS 1... Torque converter, 17... Lockup mechanism, 40... Control circuit, 41... Differential circuit,
45...Switching circuit.

Claims (1)

[Claims] 1 It has means for detecting vehicle speed, and when the vehicle speed exceeds a preset lock-up vehicle speed, it outputs a lock-up signal to place the torque converter in a lock-up state where the input and output are directly connected, and the lock-up is released when the vehicle speed is set in advance. In a lock-up control circuit for a lock-up type automatic transmission that outputs a lock-up release signal when the speed drops below the vehicle speed to disable direct connection between the input and output of the torque converter, the lock-up control circuit includes a means for detecting vehicle deceleration and a plurality of lock-up release vehicle speeds. A lock-up release signal switch that selects and outputs a signal corresponding to the lock-up release vehicle speed on the high-speed side when the deceleration exceeds a set value, and outputs a lock-up release signal when the vehicle speed signal corresponding to the vehicle speed falls below this output signal. A lock-up control circuit for a lock-up automatic transmission, characterized by comprising a circuit.