JPH05209668A - Fluid transmission device with lockup clutch - Google Patents

Abstract

PURPOSE:To surely prevent an engine stall at the time of a rapid brake in the lockup-on state by providing an elastic member pressing a lockup clutch provided on the fluid transmission device of a torque converter tube to a driving member to couple them. CONSTITUTION:A turbine runner 7 faced to a pump impeller 1 is arranged on a torque converter, and a stator 11 integrated with the outer race of a one- way clutch 10 is arranged on the inner periphery side. A lockup clutch 12 and a damper mechanism 13 are provided between the inner face of a front cover 5 and the turbine runner 7. A spring receiver 29 is provided at a portion near the outermost periphery of the outer periphery of the turbine runner 7, and a coil spring 30 is arranged between the spring receiver 29 and the lockup clutch 12. A disk spring 31 pressing the turbine runner 7 to the right and a disk spring 33 pressing the lockup clutch 12 to the front cover 5 side are arranged on the inner periphery side of the lockup clutch 12.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydraulic power transmission device with a lockup clutch such as a torque converter in an automatic transmission for a vehicle.

[0002]

2. Description of the Related Art In a hydraulic power transmission device such as a torque converter, a difference in rotational speed between a pump impeller, which is a member on the driving side, and a turbine runner, which is a member on the driven side, cannot be avoided. It is inferior to the clutch means using a plate. In order to eliminate such a defect, conventionally, a lockup clutch that directly connects a member integrated with a pump impeller and a member integrated with a turbine runner has been built in a torque converter.

The lock-up clutch is provided in order to reduce power transmission loss between the engine and the transmission, but it is a state in which driving force is transmitted from the engine to the automatic transmission. Not only that, it may be engaged even in the engine braking state (coast state). That is, in an engine of the type that injects fuel into the intake air, the lockup clutch is engaged and fuel injection is stopped and the engine is rotated by the torque from the transmission during the coast when the engine speed is equal to or higher than a predetermined speed. By doing so, fuel efficiency is improved. In this way, when the vehicle speed is equal to or lower than the predetermined vehicle speed when braking is performed by the brake operation while the engine is in the state where the lockup clutch is engaged and the fuel cut is being performed,
It causes an engine stall. That is, since the transfer torque capacity of the lockup clutch is larger than the transfer torque capacity of the torque converter through the fluid, when braking is performed by the brake operation, the engine has the action of lowering the rotation speed with a large torque. If the engine speed is low at the fuel cut state, the engine will stall. The present applicant has already proposed a device for eliminating such inconvenience in Japanese Patent Application No. 3-113165. This is because when the vehicle speed in the so-called lockup-on state in which the lockup clutch is engaged is less than or equal to a predetermined vehicle speed, the hydraulic pressure in which the lockup clutch is engaged is temporarily stopped when sudden braking is performed. It is configured so as to be lowered.

[0004]

In the above-mentioned conventional device proposed by the present applicant, since the transmission torque capacity of the lock-up clutch decreases as the hydraulic pressure decreases, the torque acting to decrease the rotation of the engine. Becomes smaller. However, in the hydraulic system, there is an unavoidable delay in response because the outer shell and gas such as mixed air act as an accumulator, or the pipeline resistance acts to hinder the supply and discharge of hydraulic pressure. Even if control is performed to reduce the hydraulic pressure that engages the lockup clutch based on the detection of what has been done, that hydraulic pressure actually drops, or the transfer torque capacity of the lockup clutch actually drops. In order to do so, it requires a certain amount of time. Therefore, during that delay time, the transfer torque capacity of the lockup clutch is large to some extent,
If a large torque acts on the engine to reduce its rotation and the vehicle speed is equal to or lower than a predetermined vehicle speed, the engine stalls.

Such an inconvenience can be avoided by increasing the engine rotational speed at which fuel cut is stopped, that is, the engine rotational speed at which fuel injection is restarted. Since it becomes shorter, fuel efficiency may not be improved sufficiently.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a fluid transmission device with a lockup clutch capable of preventing engine stall during sudden braking in the lockup / on state. To do.

[0007]

In order to achieve the above object, the present invention rotates a turbine runner by a fluid flow generated by a rotationally driven pump impeller and is integrated with the turbine runner. In a fluid transmission device with a lockup clutch, which is provided to rotate and selectively engages a drive side member that rotates together with a pump impeller by hydraulic pressure, the lockup clutch is engaged with the drive side member. It is characterized in that it has an elastic member that is pressed so as to cause it to move.

[0008]

The lock-up clutch in the fluid transmission of the present invention also rotates together with the turbine runner, and selectively engages with the drive side member integrated with the pump impeller by hydraulic pressure, whereby the torque generated by the pump impeller and the turbine runner is increased. The torque is transmitted in parallel with the transmission.
This lockup clutch is pressed not only by the hydraulic pressure but also by the elastic member in the engaging direction, so that the hydraulic pressure for generating the required transmission torque capacity is
It is lowered according to the elastic force of the elastic member. Therefore, due to the expansion of the outer shell of the fluid transmission device and the reduction of the compressed amount of gas such as air in the device, the response when lowering the hydraulic pressure is improved. Therefore, if sudden braking is performed while the vehicle is running in the lockup / on state below the predetermined vehicle speed and the hydraulic pressure that engages the lockup clutch is temporarily reduced, the hydraulic pressure immediately drops to the predetermined hydraulic pressure. As a result, the transmission torque capacity of the lockup clutch is reduced, and as a result, engine stall is prevented.

[0009]

Embodiments of the present invention will now be described with reference to the drawings. FIG. 1 is a sectional view showing an embodiment of the present invention, in which a shell 2 of a pump impeller 1 is welded to a front cover 5 via a ring-shaped intermediate member 4 integrally formed with a protrusion 3 to be integrated. The shell 2, the intermediate member 4, and the front cover 5 form a torque converter housing 6. A turbine runner 7 is arranged so as to face the pump impeller 1, and the turbine runner 7 is integrally attached to a hub 8 by a rivet 9. Further, a stator 11 integrated with the outer race of the one-way clutch 10 is arranged on the inner peripheral side of the pump impeller 1 and the turbine runner 7. A lockup clutch 12 and a damper mechanism 13 are provided between the inner surface of the front cover 5 and the turbine runner 7.

The lock-up clutch 12 is an annular plate-like member along the rear surface (left side surface in FIG. 1) of the turbine runner 7, and has a cylindrical portion 14 having a short axial length on its inner peripheral portion.
Is formed, and the cylindrical portion 14 forms the hub 8
Is fitted to the outer peripheral surface of the so as to be movable in the axial direction. In addition,
The outer peripheral surface of the hub 8 and the cylindrical portion 14 are liquid-tightly sealed by a seal ring 15 attached to the hub 8. Also, a plurality of protrusions 16 that act as meshing teeth
Are formed from the cylindrical portion 14 toward the inner peripheral side, while the hub 8 is inserted between the protrusions 16 and
A protrusion (not shown) that meshes with the lock-up clutch 12 and the hub 8 is integrated in the circumferential direction by the protrusion 16 and the protrusion.
Further, the friction material 1 is provided on the outer peripheral portion of the surface of the lockup clutch 12 opposite to the turbine runner 7 side (the surface on the left side in FIG. 1).
8 is attached.

The damper mechanism 13 is arranged between the lock-up clutch 12 and the front cover 5. The damper mechanism 13 sandwiches the drive member 19 which is an annular plate-like member and the drive member 19 at the same time. The driven member 21 that holds the damper spring 20 is mainly configured. The driven member 21 further includes an annular main member (damper mass) 22 having a relatively large inertial mass and a cover member 2 attached to one side surface (left side surface in FIG. 1) of the main member 22.
3 and 3. The main member 22 is rotatably fitted to a cylindrical boss portion provided on the inner peripheral portion of the inner surface of the front cover 5 at the inner peripheral end thereof, and the cover member 23 is provided between the main member 22 and the main member 22. The drive member 19 and the damper sprig 20 arranged inside the window hole of the drive member 19 are attached to the surface of the main member 22 on the front cover 5 side by the rivets 25 while sandwiching the drive member 19 and the damper sprig 20. Therefore, when the driving member 19 and the driven member 21 rotate relative to each other, the damper spring 20 is sandwiched and compressed by the two members 19 and 21.

The lockup clutch 12 is constructed so as to operate by the pressure difference between the front side and the back side thereof (that is, the pressure difference between the damper mechanism 13 side and the turbine runner 7 side) and the elastic force. The following configuration is provided to ensure the difference. That is, the main member 2
2, an annular protrusion 26 protruding toward the front cover 5 is formed at a position smaller than the inner diameter of the cover member 23, and a cylindrical portion 27 having an outer diameter slightly smaller than the inner diameter of the annular protrusion 26 is formed on the front cover 5. It is formed on the inner surface, and these annular projections 26 and the cylindrical portion 27 are fitted to each other, and a space between them is sealed in a liquid-tight state by a seal ring 28 attached to the cylindrical portion 27.

A spring bearing 29 is attached to a portion of the outer peripheral surface of the turbine runner 7 near the outermost periphery, and a coil spring 30 is arranged between the spring bearing 29 and the lockup clutch 12. Further, a disc spring 31 is fixed to the outer peripheral side of the cylindrical portion 14 formed on the inner peripheral portion of the lockup clutch 12 by a snap ring 32, and the outer peripheral portion of the disc spring 31 connects the turbine runner 7 to the right side of FIG. It contacts the outer surface of the turbine runner 7 so as to push in the direction. Furthermore, between the protrusion 16 acting as the engaging tooth of the lockup clutch 12 and the side surface of the hub 8, the protrusion 16 or the lockup clutch 1 is provided.
A disc spring 33 that presses 2 toward the front cover 5 side is arranged, and this is fixed to the hub 8 by a snap ring 34.

The hydraulic control means for controlling the engagement and disengagement of the lockup clutch 12 will be described.
An oil passage 35 that communicates with a portion of the lockup clutch 12 on the turbine runner 7 side and an oil passage 36 that communicates with a portion of the damper mechanism 13 side are provided. These oil passages 35 and 36 are lockup relays. It is connected to the valve 37. The lock-up relay valve 37 is for selectively supplying the converter hydraulic pressure regulated by a secondary regulator valve (not shown) to the oil passages 35 and 36, and the spool 38 is on the upper side of the drawing. In the state where it is located, the oil passage 35 is communicated with the input port 39, and the oil passage 36 is communicated with the drain port 40,
Further, the oil passage 35 is communicated with the cooler port 41 and the oil passage 36 is communicated with the input port 39 when the spool 38 is located on the lower side of the drawing. Further, a lock-up solenoid valve 44 for closing the drain port in the OFF state is provided in an oil passage 43 for supplying the line oil pressure PL to the control port 42 of the lock-up relay valve 37, and a communication passage for connecting the oil passages 35 and 36 is provided. A passage 45 is formed, and in this communication passage 45, the oil passage 45 is turned off.
Is provided with a solenoid valve 46.

Next, the operation of the above torque converter will be described. In the torque converter described above, the lock-up clutch 12 is released, the lock-up clutch 12 is pressed by the hydraulic pressure and the coil springs 30 and the disc springs 31 and 33 to be engaged, and the lock-up clutch 12 is There are three possible modes in which the coil spring 30 and the disc springs 31 and 33 are pressed and engaged with each other.
This is achieved by turning 4, 46 on or off.

That is, if both solenoid valves 44 and 46 are turned off, the line oil pressure PL is supplied to the control port 42 of the lock-up relay valve 37, and the spool 38 drops to the lower side of FIG. Hydraulic pressure is supplied between the lockup clutch 12 and the damper mechanism 13 via the oil passage 35, and the turbine runner 7 is connected via the oil passage 35.
Since the pressure is discharged from the side, the lockup clutch 12 is released from the main member 22 of the damper mechanism 13 against the elastic force of the coil spring 30 and the disc springs 31 and 33, and is in the released state.

If only the lock-up solenoid valve 44 is turned on, the pressure is discharged from the control port 42 of the lock-up relay valve 37 so that the spool 38 is located at the upper side in the figure as shown in FIG. The converter hydraulic pressure is supplied to the turbine runner 7 side via the passage 35, and is discharged from between the lockup clutch 12 and the damper mechanism 13 via the oil passage 36. The lock-up clutch 12 is brought into an engaged state by being pressed by the disc springs 30 and 33 and the disc springs 31 and 33 and pressed against the main member 22.

On the other hand, when the solenoid valve 46 is turned on, regardless of whether the lockup solenoid valve 44 is on or off, the oil passages 35 and 36 communicate with each other so that the hydraulic pressures on both sides sandwiching the lockup clutch 12 become equal. Therefore, the lockup clutch 12 is pressed against the main member 22 by the coil spring 30 and the disc springs 31 and 33 to be in the engaged state. In this case, the torque transmission capacity of the lockup clutch 12 is naturally small.

A control example in the case where the above torque converter is connected to an engine for performing a fuel cut during coasting will be described below. FIG. 2 is a flow chart showing an example of the control routine. Read data such as degree, vehicle speed or lockup map. Next, in step 2, it is judged whether or not the condition for engaging the lockup clutch 12, that is, the lockup condition is satisfied. If the lockup condition is satisfied, the throttle valve is closed in step 3. It is judged whether or not the fuel cut state is in the state. If the determination result is "yes", the process proceeds to step 4 to set the lockup solenoid valve 44 off and the solenoid valve 46 on. That is, as described above, each oil passage 3
The pressure is discharged from 5, 36 to equalize the hydraulic pressures on both sides of the lockup clutch 12 so that the lockup clutch 12 is
Are engaged by the elastic force of the coil spring 30 and the disc springs 31 and 33, so that the transmission torque capacity is low. Therefore, even if sudden braking is performed in this state, the transmission torque capacity of the lockup clutch 12 is low, so that if the braking torque applied to the engine from the automatic transmission side is large to a certain extent, the lockup clutch 12 slips, in other words. The lockup clutch 12 acts as a torque limiter, and alleviates the decrease in engine speed.

On the other hand, if the result of the determination in step 3 is "no", fuel cut is not performed in the lockup state, so the routine proceeds to step 5 to turn on the lockup solenoid valve 44 and turn off the solenoid valve 46. .. In this case, as described above, the converter hydraulic pressure is supplied to the turbine runner 7 side, and the pressure is exhausted from between the lockup clutch 12 and the damper mechanism 13,
The lock-up clutch 12 is pressed and engaged by the hydraulic pressure and the elastic force of each elastic body, that is, the coil spring 30 and each of the disc springs 31 and 33, so that a so-called complete lock-up state is established.

If the result of the determination in step 2 is "no", the process proceeds to step 6 to turn off the lockup solenoid valve 44 and turn off the solenoid valve 46. As a result, the converter hydraulic pressure is supplied between the lockup clutch 12 and the damper mechanism 13,
The lockup clutch 12 is released.

The advantage of performing the control of step 4 described above will be explained here. In FIG. 3, the engine speed in the fuel cut state is N1, and t1 is
When the braking is started at the time point, the engine speed starts to decrease due to the braking torque after a predetermined delay time. The rate of decrease in the rotational speed increases in accordance with the braking torque, but in the conventional case, the delay time for releasing the lock-up clutch is long and the transmission torque capacity is large, so that the thin solid line in FIG. The engine speed drops sharply. On the other hand, in the above-described torque converter, since the lockup hydraulic pressure may be low due to the coil spring 30 and the disc springs 31 and 33, the hydraulic pressure for lockup quickly decreases, and Since the transmission torque capacity in the state of being engaged by the elastic force of the coil spring 30 and the like is low, the rate of decrease of the engine speed becomes gentle as shown by the thick broken line in FIG. Therefore, if the delay time for releasing the lockup clutch is T,
Conventionally, an engine stall may occur during that time, but in the above torque converter, the engine speed can be maintained at a relatively high speed until the delay time elapses.
It is also possible to lower it. Therefore, in the above torque converter, it is possible to further improve the fuel efficiency by widening the lockup region.

As described above, in the torque converter shown in FIG. 1, by turning on the solenoid valve 46, the lockup clutch 12 can be engaged only by the elastic force and the transmission torque capacity thereof can be lowered.
It is possible to effectively prevent the so-called crimping caused by the torsional vibration of the drive system, and also to prevent the lock-up clutch 12
It is also effective to reduce the engagement shock when engaging the. That is, for example, when the engine torque rapidly changes due to a large change speed and change amount of the throttle opening, and there is a high possibility that a rattling occurs, the solenoid valve 46 is turned on and the lockup clutch 12 is turned on. Engage only by elastic force,
After that, the lockup solenoid valve 4 is activated when the rotational speed of the drive system approaches the rotational speed after the throttle opening is changed.
4 is turned on and the solenoid valve 46 is turned off to bring the lockup clutch 12 into a complete lockup state. By doing so, it is possible to avoid a situation in which a large torque is rapidly transmitted between the engine and a drive system such as an automatic transmission by slipping the lockup clutch 12,
As a result, the occurrence of crimping is prevented.

When the vehicle is in a running state where the lockup clutch 12 is engaged, first the solenoid valve 46 is turned on to equalize the hydraulic pressures on both sides of the lockup clutch 12 so that the lockup clutch 12 is engaged. 12 is engaged only by elastic force. In this state, the transmission torque capacity of the lockup clutch 12 is small, and therefore the lockup clutch 12 slips when the engine torque is large. When such a state close to so-called half lockup is continued for a predetermined time, the rotation speed of the drive system gradually increases, so that the lockup clutch 12 is completely locked up when the rotation speed of the drive system reaches the predetermined rotation speed. In the state, the engagement shock is prevented or reduced.

The control routines for the control associated with the sudden braking at the time of the fuel cut, the control for preventing the crimp and the control for reducing the engagement shock are shown in one flow chart as shown in FIGS. 4 and 5. Is. The numbers circled in FIGS. 4 and 5 indicate that lines with the same numbers are connected to each other.

First, at step 10, various data such as throttle opening, vehicle speed, lockup map, shake map, and brake signal are read. Here, the lock-up map shows a traveling state in which the lock-up clutch 12 is engaged, that is, a lock-up region by a vehicle speed and a throttle opening, and is schematically shown in FIG. Further, the shake map is a state in which a sudden change in the throttle opening that may cause a shake is represented by a change amount and a change speed of the throttle opening, and is schematically shown in FIG.
The shaded area in FIG. 7 is the area in which it is determined that the throttle opening has suddenly changed.

After reading the data in step 10, it is determined in step 11 whether or not the lockup condition is satisfied. If the determination result is "NO", control for releasing (locking up / off) the lockup clutch 12 is executed in step 12, and the process returns. If the determination result is "yes", it is determined in step 13 whether or not the fuel cut is being performed with the throttle valve closed. If the determination result is "yes", the process proceeds to step 14. 2, the lockup solenoid valve 44 is turned off and the solenoid valve 46 is turned on to engage the lockup clutch 12 only by the elastic force, as in the control of step 4 in FIG.

If the judgment result in step 13 is "NO", it is judged in step 15 whether or not the judgment of the sudden change of the throttle opening is established. Go ahead and set the flag F1 to "1"
Determine whether or not. This flag F1 is set to "1" to indicate that the timer T1 is counting the time. If it is not "1", the process proceeds to step 17 and the timer T1 is reset to zero and started. After that, in step 18, the flag F1 is set to "1". If the determination result in step 16 is "yes" and if the control in step 18 is executed, the process proceeds to step 19 and it is determined whether the count value of the timer T1 is a predetermined time α or more. When the predetermined time α has not elapsed, the routine proceeds to step 20, where the same control as in step 14 is executed and the lockup clutch 12 is engaged only by the elastic force. If the predetermined time α has elapsed, the routine proceeds to step 21, where the lockup solenoid valve 44 is turned on and the solenoid valve 46 is turned off to bring the lockup clutch 12 into a complete lockup state. afterwards,
In step 22, the flag F1 is reset to zero and the process returns.

Further, the judgment result of step 15 is "no".
If so, it is determined in step 23 whether the flag F2 is "1". The flag F2 is set to "1" to indicate that the timer T2 is counting the time. If the time counting is not started, the timer T2 is reset to zero in step 24 and started. Then, in step 25, flag F
2 is set to "1", and in step 26, the lockup solenoid valve 44 is turned off and the solenoid valve 4
Control to turn on 6 is executed, and the process returns. If the timer T2 has started counting the time, the routine proceeds to step 27, where it is judged whether or not the count value has passed the predetermined time β. If not, the routine proceeds to step 26. If the time has passed, the routine proceeds to step 28, where control is performed to bring the lockup clutch 12 into the complete lockup state. Then, in step 29, the flag F2 is reset to zero and the process returns.

By the way, according to the present invention, the lock-up clutch 12 may be constructed so as to be operated by elastic force in addition to hydraulic pressure, and the elastic force is not limited to the coil spring and the disc spring shown in FIG. That is, FIG. 8 is a partial sectional view showing another embodiment of the present invention,
The torque converter shown here has a structure in which the outer shell of the turbine runner 7 is elastically displaced toward the damper mechanism 13 side, and the lockup clutch 1 is provided on the outer surface thereof.
2 are arranged in contact with each other, and the lockup clutch 12 is pressed by the turbine runner 7.

FIG. 9 is a partial sectional view showing still another embodiment of the present invention. In this example, the lockup clutch 12 is divided into an inner peripheral side portion 12a and an outer peripheral side portion 12b. , These are connected by a leaf spring 12c, and the friction material 18 is connected to the damper mechanism 13 by the leaf spring 12c.
The main member 22 is pressed.

In either of the constructions shown in FIG. 8 or the construction shown in FIG. 9, the lockup clutch 12 is engaged by the hydraulic pressure and the elastic force, and therefore operates in the same manner as the torque converter shown in FIG. Can be made

Although any of the above embodiments has been described by taking the torque converter as an example, the present invention is not limited to the torque converter but can be widely applied to general hydraulic transmissions with lockup clutches.

[0034]

As is apparent from the above description, in the fluid transmission device of the present invention, the lockup clutch is engaged by the hydraulic pressure and the elastic force of the elastic member. Therefore, the hydraulic pressure for engaging the lockup clutch is controlled. It can be lowered according to the elastic force, as a result, the degree of expansion of the outer shell of the fluid transmission and the compression of bubbles are reduced, the unexpected accumulator action is reduced and the delay of the release of the lockup clutch is shortened. In addition, the transient transmission torque capacity can be reduced. Therefore, it is extremely unlikely that an engine stall will occur even during sudden braking in the fuel cut state, and accordingly, the fuel cut speed can be reduced and the fuel cut time can be lengthened, so that the fuel consumption can be further improved. Further, since the hydraulic pressure may be low, the container of the fluid transmission device can be made thin and lightweight. Therefore, according to the present invention, the device can be downsized and the weight can be reduced.

[Brief description of drawings]

FIG. 1 is a partial sectional view showing an embodiment of the present invention.

FIG. 2 is a flowchart showing an example of a control routine at the time of fuel cut.

FIG. 3 is a time chart showing changes in engine speed in comparison with a conventional example.

FIG. 4 is a partial flowchart showing a part of an example of a comprehensive control routine.

FIG. 5 is a partial flowchart showing another portion of an example of a comprehensive control routine.

FIG. 6 is a schematic diagram showing an example of a lockup map.

FIG. 7 is a diagram schematically showing an example of a shacli map.

FIG. 8 is a partial cross-sectional view showing another example of the present invention.

FIG. 9 is a partial cross-sectional view showing still another example of the present invention.

[Explanation of symbols]

 1 Homp Impeller 5 Front Cover 7 Turbine Runner 12 Lockup Clutch 19 Drive Member 20 Damper Spring 30 Coil Spring 31, 33 Disc Spring

Claims (1)

[Claims] 1. A hydraulic fluid is applied to a drive side member that rotates a turbine runner by a fluid flow generated by a rotationally driven pump impeller and that rotates together with the turbine runner and that rotates together with the pump impeller. A fluid transmission device with a lock-up clutch including a lock-up clutch that selectively engages, wherein the lock-up clutch includes an elastic member that presses the lock-up clutch to engage with the drive-side member. Fluid transmission device.