JPH0447484Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Field of Application) The present invention relates to a lock-up control device in an automatic transmission, particularly in an automatic transmission equipped with a torque converter with a lock-up clutch.

(Prior art) Automatic transmissions used in automobiles combine a torque converter and a gear transmission using a planetary gear mechanism to automatically switch gears to the optimum gear according to the driving condition of the vehicle. The torque converter increases the torque at low vehicle speeds, low gears, etc., and also alleviates and absorbs shocks that occur during gear changes.

However, since this torque converter transmits power through fluid, automatic transmissions that use it have lower power transmission efficiency than manual transmissions that transmit power mechanically. Cars equipped with this have the disadvantage of poor fuel efficiency. Therefore, in this type of automatic transmission, it is recommended to provide a lock-up clutch that mechanically directly connects the input and output sides of the torque converter at high vehicle speeds or at high gears when the above-mentioned torque increasing effect is not required. It is being said. As shown in, for example, Japanese Patent Laid-Open No. 57-54767, this lock-up clutch includes a converter cover that connects an engine output shaft and an impeller in a torque converter, and a converter cover that connects an engine output shaft and an impeller, and a lock-up clutch that faces the cover and is connected to a turbine. The impeller and the turbine, that is, the input and output sides of the torque converter, are directly connected by pressing the plate against the converter cover. For example, in the case of an automatic transmission with 4 forward speeds, 3,
In the case of a transmission with 4 speeds and 3 forward speeds, the lock-up clutch is engaged in 2nd and 3rd speeds to improve power transmission efficiency or fuel efficiency when driving at these speeds.

However, when the lock-up clutch is engaged in 3rd and 4th gears or 2nd and 3rd gears as described above, it is necessary to prevent shift shock when shifting between 3rd and 4th gears or between 2nd and 3rd gears. , control is required to once release the clutch and then re-engage it after shifting. Therefore, a device in which this control is performed electrically is disclosed, for example, in Japanese Patent Application Laid-Open No. 56-39354, but a device using such electrical control has the disadvantage of a complicated structure. Furthermore, in controlling the release and engagement of the lock-up clutch during the gear shift, there is a problem in that if the lock-up clutch is rapidly engaged after the gear shift, a torque shock occurs, which deteriorates the ride comfort of the vehicle.

(Purpose of the invention) The purpose of this invention is to solve the above-mentioned problems in automatic transmissions equipped with a torque converter with a lock-up clutch. The present invention aims to prevent the occurrence of torque shock when the lock-up clutch is engaged by gently engaging the lock-up clutch after shifting.

(Structure of the invention) The lockup control device for an automatic transmission according to the invention is characterized in that it is structured as follows in order to achieve the above object.

That is, in a configuration in which a piston plate connected to a turbine of the torque converter is movable in the axial direction and is provided opposite to a converter cover that connects the engine output shaft and an impeller in the torque converter, the piston plate is connected to the converter cover. A first pressure chamber that presses against the converter cover and a second pressure chamber that separates the pressure chamber from the converter cover are provided, and a spool that selectively switches the supply of hydraulic pressure to these pressure chambers; and a lockup control valve having a spring biased to a supply position. Then, a control signal hydraulic pressure is applied to this control valve, which causes the control valve to supply hydraulic pressure to the second pressure chamber by being drained once during gear shifting, and then to supply hydraulic pressure to the first pressure chamber by increasing the pressure again. A control port to which a lock-up control line to be supplied is connected and which applies the control signal hydraulic pressure to a first pressure receiving surface formed on one side of the land provided on the spool, and a control port having a pressure receiving area from the first pressure receiving surface. A delay port is provided which has a second pressure receiving surface formed on the other side of the small land and whose volume increases or decreases as the spool moves. moreover,
A drain passage is connected to the delay port, and the drain passage is provided with a check valve that closes when the spool moves as the control signal oil pressure increases and opens when the spool moves in the opposite direction as the control signal oil pressure falls; A constriction portion is formed on the spool to communicate the control port and the delay port.

According to such a configuration, during gear shifting, the control signal hydraulic pressure is first drained, and the spool of the lock-up control valve is accordingly moved to a position for supplying hydraulic pressure to the second pressure chamber by the biasing force of the spring. Sometimes, by opening the check valve, the volume of the delay port is easily increased and the spool moves quickly. After that, the control signal oil pressure increases again,
When the spool moves to the position for supplying hydraulic pressure to the first pressure chamber, the check valve is closed, so the hydraulic oil in the delay port is not discharged from the drain passage, but gradually flows to the control port through the constriction section. The fluid will flow, and the spool will gradually move accordingly. Therefore, during gear shifting, the clutch is released quickly by supplying hydraulic pressure to the second pressure chamber, but after gear shifting is completed, the clutch is engaged slowly by supplying hydraulic pressure to the first pressure chamber. It will be done. Note that when the volume of the delay port increases, hydraulic oil is introduced from the throttle portion, and when the volume of the port decreases, this hydraulic oil prevents the spool from moving quickly. In addition, when the control signal oil pressure is introduced into the control port, some of the hydraulic oil also flows into the delay port via the throttle part, but the second pressure receiving surface on the side of the delay port is on the side of the control port. Since the pressure receiving area is smaller than the first pressure receiving surface of the first pressure receiving surface, the spool will not move toward the control port side due to the hydraulic pressure on the delay port side.

(Example) Hereinafter, an example of the present invention shown in the drawings will be described.

As shown in FIG. 1, an automatic transmission 1 includes a torque converter 1 driven by an engine output shaft 2.
0 and a gear transmission 30 using a planetary gear mechanism driven by the output of the torque converter 10.
The main components are a hydraulic control circuit 50 and a hydraulic control circuit 50, which will be described later.

The torque converter 10 includes a converter cover 11 coupled to the engine output shaft 2 via a drive plate 3, an impeller 12 integrally provided within the cover 11, and an impeller 12.
A turbine 13 is rotatably provided within the converter cover 11 so as to face the turbine 13, and a turbine 13 is disposed between the turbine 13 and the impeller 12 and supported between the fixed member 14 via a one-way clutch 15. The turbine 13 is connected to an output shaft 18 via a turbine hub 17. Also, this torque converter 1
A lock-up clutch 20 is provided inside the converter cover 11 and a piston plate 19 disposed opposite the inner surface 11a of the cover 11. Above piston plate 1
9 is capable of moving in the axial direction to come into contact with and away from the inner surface 11a of the converter cover 11, and is spline-coupled to the turbine hub 17 so as to rotate integrally with the turbine 13 or the output shaft 18. ing. The space behind the piston plate 19 in the converter cover 11 serves as a first pressure chamber 21 that presses the plate 19 against the cover inner surface 11a, and the space between the plate 19 and the cover inner surface 11a serves as a first pressure chamber 21 that separates them. There are two pressure chambers 22, which are communicated with a lock-up engagement line 23 and a release line 24, respectively.

On the other hand, the gear transmission 30 has a double planetary gear mechanism 31, and has a plurality of friction elements such as a forward clutch 32, a reverse clutch 33, a coast clutch 34, a 3rd-4th speed clutch 35, and a low reverse brake 36. , and a 3-4 speed brake 37, and these friction elements 32-3
7, the power from the torque converter output shaft 18 is switched to four forward speeds and one reverse speed and transmitted to the output gear 38. The friction elements 32 to 36 are each equipped with a hydraulic actuator, and each actuator is connected to an operating hydraulic pressure supply line 3 led from a hydraulic control circuit to be described later.
The actuator 37a of the 3rd-4th speed brake 37 has a 3rd speed port 37a' and a 4th speed port 37a'' on both sides of the piston, as shown in FIG. 3rd and 4th speed lines 44 and 44 are connected to both ports 37a' and 37a'', respectively.
45 are connected.

Next, according to FIG. 3, the above lines 23, 24, 3
9 to 45 of the torque converter 10,
Second pressure chambers 21, 22 and each friction element 32 to 37
The hydraulic control circuit 50 that controls the supply and discharge of hydraulic pressure to the actuator will be explained.

First, this circuit 50 is equipped with an oil pump 51 as a hydraulic pressure generation source, a regulator valve 52 that regulates the discharge pressure of the oil pump 51 to a predetermined value, and as main circuit components: A manual valve 54 into which the hydraulic pressure regulated by the regulator valve 52 is introduced via a main line 53, and a hydraulic pressure supply passage to each of the friction elements 32 to 37 that operates depending on the operating state. 1-2 shift valve 55, 2-3 to switch
A shift valve 56 and a 3-4 shift valve 57 are provided.

The manual valve 54 has P, R,
It has N, D, S, and 1 ranges, and when shifted to the D range as shown in the figure, the main line 53 is communicated with the first and second ports 54a and 54b.

Further, each of the shift valves 55, 56, 57 has spools 55a, 56a, 57a, respectively, and depending on the positions of these spools 55a to 57a,
The first and second ports 5 of the manual valve 54
Lines 58, 59 led from 4a, 54b are selectively communicated with lines 39-45 leading to the actuators of each of the friction elements 32-37. In particular, the spool 55 shown in the figure
Arrangement of a to 57a, i.e. 1-2 shift valve 5
5 and 2-3 shift valve 56 spool 55
a, 56a is located on the left side and the spool 57a of the 3-4 shift valve 57 is located on the right side, the first port 5 of the manual valve 54
4a communicates with the 3rd speed port 37a' of the 3rd-4th speed brake actuator 37a via the line 58, the 2-3 shift valve 56, the line 60, the 3-4 shift valve 57, and the line 44. Hydraulic pressure is introduced to 37a', the 3rd-4th speed brake 37 is released, and the transmission 30 is placed in the 3rd speed state. In addition, when the spool 57a of the 3-4 shift valve 57 also moves to the left from this state, the second port 54b of the manual valve 54 is connected to the line 59, the 1-2 shift valve 55, the line 61, and the
-4 shift valve 57 and the 4-speed brake actuator 37a via the line 45.
3-4 speed brake 3
7, the transmission 30 enters the fourth speed state.

Therefore, the above 3-4 shift valve 57 and 3-4
a third speed line 44 to which hydraulic pressure is introduced during third speed between the fast brake actuator 37a;
A 3rd speed lockup line 62 and a 4th speed lockup line 63 are branched off from the 4th speed line 45 to which hydraulic pressure is introduced during 4th speed, and
A 3-speed lock-up valve 64 and a 4-speed lock-up valve 6 are provided between the upstream sides 62a, 63a and the downstream sides 62b, 63b of both lines 62, 63, respectively.
5 is interposed. The 3rd speed lockup valve 64 shuts off between the upper and downstream sides 62a and 6b of the 3rd speed lockup line 62 when hydraulic pressure is introduced through the cutoff line 63c branched from the 4th speed lockup line 63. , and the 4-speed lock-up valve 65 is connected to the 3-speed lock-up line 6.
When hydraulic pressure is introduced through a cut-off line 62c branched from the lock-up line 62, the upper and downstream sides 63a and 63b of the 4-speed lock-up line 63 are cut off. As a result, in 3rd gear, hydraulic pressure is introduced from the 3rd gear line 44 through the 3rd gear lockup valve 64 to the downstream side 62b of the 3rd gear lockup line 62, and in 4th gear, the hydraulic pressure is introduced from the 4th gear line 45 to the 4th gear lockup valve 64. Hydraulic pressure is introduced to the downstream side 63b of the 4-speed lockup line 63 via the valve 65.

And this 3 and 4 speed lock up line 6
The downstream sides 62b and 63b of 2 and 63 join together via a passage switching ball 66 to form a lockup control line 67, which is led to a lockup control valve 68.

This lock-up control valve 68 is
From the oil pump 51 to the regulator valve 5
an input port 70 to which a converter line 69 led through the converter line 69 is connected, and first and second output ports 72 and 73 selectively communicated with the input port 70 depending on the position of the spool 71; Control port 7 where the lockup control line 67 is controlled
4, and the first and second output ports 7
2 and 73 are controlled by the lock-up engagement line 23 and release line 24, and these lines 2
3 and 24, respectively, to the first and second pressure chambers 21 and 22 in the torque converter 10. As shown in the figure, when the spool 71 is positioned to the right against the spring 75 due to the hydraulic pressure in the control port 74, the converter line 69 is connected from the first output port 72 to the fastening line 23.
When hydraulic pressure is not introduced into the control port 74, the spool 71 is moved to the left in the drawing by the spring 75, and the converter line 69 is connected to the converter line 69.
is connected to the release line 24 from the second output port 73.

Also, this lock-up control valve 6
8 is provided with a delay port 76 that faces the control port 74 via a land 71a at one end of the spool 71. This daily port 7
6 is connected to a drain passage 77 whose one end is open to oil or air, and the drain passage 77 is provided with a check valve 78. This check valve 78 is activated when the spool 71 moves leftward from the position shown in the figure.
When the volume of the delay port 76 increases, it opens to open the drain passage 77, and when the spool 71 moves from the left position to the right and the volume of the delay port 76 decreases, it closes to open the drain passage 77. Cut off. And the land 71 of the spool 71
A is provided with a cutout 71b serving as an orifice that communicates the control port 74 and the delay port 76 on both sides, and the land 71
The first pressure receiving surface provided on the side on the control port 74 side of a is set to have a larger pressure receiving area than the second pressure receiving surface provided on the side on the delay port 76 side. Note that when the gap between the land 71a and the valve body acts as an orifice, the notch 7
1b can be omitted.

Next, the operation of the above embodiment will be explained.

Now, the manual valve 54 in the hydraulic control circuit 50 has been shifted to the D range, and as shown in FIG.
Assuming that the spools 55a and 56a of the shift valve 56 are located on the left side and the spool 57a of the 3-4 shift valve 57 is located on the right side, the main line 53
is from the first port 54a of the manual valve 54 to the line 58, the 2-3 shift valve 56, and the line 6.
0, 3-4 shift valve 57 and 3rd speed line 44
3-4 speed brake actuator 37 via
a, the third speed port 37a'
Since hydraulic pressure is supplied to a′, the first
The 3rd-4th speed brake 37 in the illustrated gear transmission 30 is released, and the device 30 is in the 3rd speed state. In this case, the 3rd speed lock up line 62 branched from the 3rd speed line 44 is
The upper and downstream sides 62a and 62b communicate through the 3-speed lockup valve 64, and further communicate with the lockup control line 67 through the passage switching ball 66, so that the control port 74 of the lockup control valve 68 is connected to the is 3rd gear line 44
The control signal from the hydraulic pressure is in a state where it is introduced. Therefore, since the spool 71 of the control valve 68 is located on the right side as shown in the figure and communicates the input port 70 and the first output port 72, the converter line 69 is communicated with the lock-up fastening line 23. ing. As a result, in the torque converter 10 shown in FIG.
0 is fastened), and the torque converter 10 is in a locked-up state in which the input side (impeller 12) and output side (turbine 13) are directly connected.

Furthermore, when the spool 57a of the 3-4 shift valve 57 moves to the left from the position shown in FIG. 3 as the vehicle speed increases from this state, the 3rd gear line 44 is drained and -4
The hydraulic pressure in the 3rd speed port 37a' of the high speed brake actuator 37a is discharged, and the main line 53 is connected to the line 59, 1-2 shift valve 5 from the second port 54b of the manual valve 54.
5, line 61, 3-4 shift valve 57 and 4
It communicates with the 4th speed port 37a'' of the 3rd-4th speed brake actuator 37a through the speed line 45, and hydraulic pressure is introduced into the port 37a''. As a result, the 3rd-4th speed brake 37 is engaged, and the gear transmission 30 is switched to the 4th speed state.
After the shift to the fourth gear is completed, the hydraulic pressure from the third gear line 44 is replaced by the fourth gear.
The hydraulic pressure from the speed line 45 is introduced into the control port 74 of the lock-up control valve 68 via the 4-speed lock-up line 63, the 4-speed lock-up valve 65, and the lock-up control line 67. Similarly, hydraulic pressure is introduced into the first pressure chamber 21 of the torque converter 10 from the converter line 69 through the engagement line 23, and the lock-up clutch 20 is brought into the engaged state.

However, the 3-4 shift valve 57 as described above
When shifting between 3rd and 4th speeds due to the movement of
After the 3rd speed line 44 is drained, hydraulic pressure is introduced into the 4th speed line 45 at a certain time interval, so the lockup control valve 68 receives oil pressure from these lines 44 and 45 alternately. At the control port 74, hydraulic pressure is temporarily not introduced. Therefore, the spool 71 of the control valve 68 is once moved to the left by the spring 75 from the illustrated position, and the control port 71 is moved again after the gear change is completed.
When hydraulic pressure is introduced into 4, it is moved from the left position to the right and returns to the illustrated position. Then, during a certain period of time when the spool 71 is located on the left side, the input port 70 is connected to the second output port 7.
3, the converter line 69
The hydraulic pressure from the
It will be introduced in 2. In this way, the lock-up clutch 20 of the torque converter 10 is temporarily released during gear shifting, and is returned to the engaged state after the gear shifting is completed.

However, along with the above-described behavior of the spool 71 during gear shifting, the control valve 68
The capacity of the delay port 76 increases once and then decreases to its original state, but the check valve 78 on the drain passage 77 connected to the delay port 76 It opens and closes when it decreases. Therefore, the spool 71 has an increased allowable volume.
When the torque converter 10 moves to the left, that is, the torque converter 10
When the lock-up clutch 20 is released from the fastened state, the spool 71 is quickly moved by the biasing force of the spring 75, and the lock-up clutch 20 is quickly released. In this state, hydraulic oil is introduced from the control port 74 to the delay port 76 through the notch 71b provided in the land 71a of the spool 71, and then the spool 71
1 moves to the right and the volume of the delay port 76 decreases, that is, when the lock-up clutch 20 is tightened again, the hydraulic oil in the delay port 76 is not drained from the drain passage 77 and the above-mentioned shut-off occurs. The flow gradually flows to the control port 74 side through the notch 71b, and as a result, the spool 7
1 will also be moved gradually. As a result, the lock-up clutch 2 after the gear shift is completed.
This means that the clutch 20 is tightened loosely, thereby preventing the occurrence of torque shock due to the sudden tightening of the clutch 20. Furthermore, since the first pressure receiving surface on the control port 74 side of the land 71a has a larger pressure receiving area than the second pressure receiving surface on the delay port 76 side, when the control signal hydraulic pressure is introduced to the control port, part of the hydraulic fluid is Even if the portion flows into the delay port 76 through the notch 71b, the spool 71 will not move to the left due to the pressure.

(Effects of the invention) As described above, according to the invention, in an automatic transmission equipped with a torque converter with a lock-up clutch, the clutch is released during gear shifting.
Engagement control has come to be performed with a simple configuration using hydraulic pressure, and the engagement of lock-up clutches has become more gradual, especially after gear changes, which reduces torque shock caused by sudden engagement of the clutches. This will prevent the occurrence of such problems, and avoid deterioration of the ride comfort of the vehicle.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention, and FIG. 1 is a longitudinal sectional view showing the configuration of a torque converter and gear transmission in an automatic transmission, and FIG. 2 is an enlarged sectional view of a hydraulic actuator for a 3-4 speed brake. , 3rd
The figure is a hydraulic control circuit diagram. 2... Engine output shaft, 10... Torque converter, 11... Converter cover, 12... Impeller, 19... Piston plate, 21... First
Pressure chamber, 22...Second pressure chamber, 68...Lockup control valve, 71...Spool, 7
1a...Land, 71b...Aperture part (notch),
74...Control port, 75...Spring, 76
...Daily port, 77...Drain passage, 7
8...Check valve.

Claims (1)

[Scope of utility model registration request] a converter cover that connects the engine output shaft and the impeller of the torque converter; a piston plate that is movable in the axial direction facing the converter cover; and a first pressure chamber that presses the piston plate against the converter cover; A second pressure chamber for separating the piston plate from the converter cover, a spool for selectively switching the supply of hydraulic pressure to these pressure chambers, and a spring for biasing the spool to a position for supplying hydraulic pressure to the second pressure chamber. The lock-up control valve has a lock-up control valve that is once drained during gear shifting to supply hydraulic pressure to the second pressure chamber, and then the pressure increases again to supply hydraulic pressure to the first pressure chamber. A lock-up control line for supplying a control signal hydraulic pressure for supplying hydraulic pressure to the chamber is connected, and control for applying the control signal hydraulic pressure to a first pressure receiving surface formed on one side of the land provided on the spool. a port, and a delay port having a second pressure receiving surface formed on the other side of the land having a smaller pressure receiving area than the first pressure receiving surface, and whose volume increases or decreases as the spool moves,
Further, a drain passage provided with a check valve is connected to the delay port, and the control port and the delay port communicate with each other through a constriction formed in the spool, and the check valve receives the control signal hydraulic pressure. A lock-up control device for an automatic transmission, characterized in that it is configured to close when a spool moves as it rises, and open when it moves in the opposite direction as a control signal oil pressure falls.