JPS6149536B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a torque converter, and more particularly to a lock-up torque converter equipped with a lock-up mechanism that mechanically couples a pump impeller and a turbine runner.

In automatic transmissions that combine a torque converter and a multi-speed gear mechanism, slip occurs between the torque converter's pump impeller and the turbine runner, causing power loss even during high-speed operation when no increase in torque is required. To solve this problem, it is known to provide a lock-up clutch which mechanically couples the pump impeller and turbine runner to rotate together with each other. For example, in Japanese Patent Application Laid-open No. 54-132062, there is a converter chamber in which one end is covered with a converter cover and the other end is covered with a pump impeller that rotates integrally with the converter cover, and a pump impeller that faces the pump impeller. A lock-up torque converter is disclosed in which a turbine runner is disposed, and a lock-up clutch is provided between the turbine runner and a converter cover, the lock-up clutch rotating with the turbine runner but movable axially into frictional engagement with the converter cover. ing. In this torque converter, hydraulic oil is supplied to the pump impeller from an oil supply path formed on the outer periphery of the hollow fixed shaft of the stator, and this hydraulic oil is circulated from the pump impeller to the turbine runner to provide driving force to the turbine. A part of the oil is circulated to the pump impeller again, and the remaining part is discharged from an oil discharge path formed between the input shaft and the stator hollow fixed shaft. A portion of the hydraulic fluid is also forced radially outward from between the pump impeller and the turbine runner, creating pressure in the space between the turbine runner and the lockup clutch, which constantly Pushed in the direction of engagement. In order to hold the lock-up clutch in the disengaged state, hydraulic pressure for clutch release is supplied to the space between the lock-up clutch and the converter cover to push the lock-up clutch in the disengaged direction. By discharging the hydraulic pressure, the lock-up clutch can be engaged with the converter cover and the pump impeller and turbine runner can be coupled.

In such a torque converter, when the converter is in a stalled state, the pump impeller is rotating, so a swirling force is generated in the hydraulic oil driven by the pump impeller, and dynamic pressure is generated near the outer periphery of the converter. do. However, the hydraulic oil does not rotate between the turbine runner and the lock-up clutch because both are stationary.
The dynamic pressure becomes static pressure, and this static pressure balances the hydraulic pressure at the outer circumference. Therefore, the oil pressure in this space increases, pushing the lock-up clutch in the engaging direction. In this case, the hydraulic pressure supplied between the converter cover and the lock-up clutch during stalling may become small, and the hydraulic pressure that pushes the lock-up clutch in the engagement direction becomes greater than the disengagement hydraulic pressure, which resists this. This may cause the lock-up clutch to frictionally engage the converter cover, resulting in a so-called clutch drag phenomenon.

The structure of a turbine runner is generally such that slits are formed in the turbine shell and core made of sheet metal, and the turbine blades are inserted into the slits and installed. Therefore, it is necessary to make the slits somewhat larger. For example, between the turbine shell and the lockup clutch, some of the pressure is vented into the turbine shell and the drag problem described above does not occur. However, if such a gap exists in the turbine shell, it will be difficult to secure the hydraulic pressure necessary for lock-up, so it is preferable not to have such a gap.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems in lock-up torque converters, and to provide a lock-up torque converter which is free from the problem of lock-up clutch drag and which can easily secure lock-up hydraulic pressure.

That is, the structural feature of the present invention is that in a converter having a lock-up mechanism of the type described above, an outflow path is formed in the space between the turbine runner and the lock-up clutch to allow oil to flow out to the outside, and this outflow path is formed in the space between the turbine runner and the lock-up clutch. The reason is that a centrifugal valve that closes when the turbine rotates at high speed is installed in the passageway. This outflow passage may be formed in a part of the turbine shell at or near the turbine hub of the converter, and is configured to open when the turbine runner stops, such as when the torque converter stalls, thereby reducing the drag of the lockup clutch. There is no problem, and since it closes during high-speed rotation when lock-up is required, there is no problem in securing lock-up operating hydraulic pressure. The centrifugal valve may be configured to open even when the turbine runner rotates at low speed, but it does not necessarily need to be opened.

Hereinafter, one embodiment of the present invention will be described with reference to the drawings. The illustrated torque converter has a converter cover 3 which is connected to a drive shaft such as an engine output shaft 2 via a drive plate 1, and this converter cover 3 has a shallow cup shape and is surrounded by a pump. The periphery of the impeller shell 4 is welded to form a converter chamber 5 between the converter cover 3 and the pump impeller shell 4. Impeller blades 6 are attached to the inner surface of the shell 4 of the pump impeller, and a turbine runner 8 having turbine blades 7 facing the impeller blades 6 is arranged in the converter chamber 5 . The turbine runner 8 has a turbine shell 9 that supports the turbine blades 7 and a turbine hub 10 that supports the turbine shell 9. The turbine hub 10 is connected to the front end of the input shaft 11. The input shaft 11 extends outward through the center of the turbine shell 9 and is rotatably supported by a fixed shaft 13 fixed to the transmission case 12 .
A fixed shaft 13 extends forward around the input shaft 11 into the converter chamber 5 and supports a stator 15 via a one-way clutch 14 . A pump drive shaft 16 is provided in the center of the shell 4 of the pump impeller and extends rearward around a fixed shaft 13, and the pump drive shaft 16 is connected to a gear pump 18 in a pump housing 17 fixed to the transmission case 12. It is becoming more and more like driving.

A lock-up clutch 19 is arranged on the turbine hub 10 so as to be axially movable. The lock-up clutch 19 has a substantially disc-like shape, and has a friction member 2 at its periphery facing the converter housing 3.
has 0. An annular connecting member 21 is fixed to the lockup clutch 19 by welding or the like, and this connecting member 21 is connected to a drive plate 23 via a torsional damper 22. The drive plate 23 is attached to the outer surface of the turbine hub 10 by splines 24 so as to be movable in the axial direction. The lock-up clutch 19 is therefore axially slidable relative to the turbine runner 8, but rotates integrally therewith. As shown in the figure,
The turbine hub 10 has a space 25 between the turbine shell 9 and the lockup clutch 19 and an input shaft 1.
A radial passage, that is, an outflow path 27 is formed that connects the space 26 around the turbine runner 1 with a centrifugal valve 30 that closes when the turbine runner 8 rotates at high speed. An appropriate number of passages 27 may be provided, and the location thereof is not limited to the turbine hub 10, but may be located near the center of the turbine shell 9. An outflow passage 31 is also formed between the turbine shell 9 and the one-way clutch 14 for allowing a portion of the oil in the turbine runner 8 to flow into the space 26.

The hydraulic oil discharged from the gear pump 18 passes through a pressure regulating valve (not shown) to the pump drive shaft 16 and the fixed shaft 1.
The converter enters the converter chamber 5 on the pump impeller side through the passage between After being applied, it exits from the outflow path 31 to the space 26 as shown by the arrow, and is returned from the passage between the fixed shaft 13 and the input shaft 11. Near the outer periphery of the converter chamber 5, dynamic pressure is generated in the hydraulic oil due to the turning force applied to the hydraulic oil by the pump impeller, and this hydraulic pressure is transmitted to the space 25 and moves the lock-up clutch 19 to the left in the figure. Press. On the other hand, in order to push the lock-up clutch 19 to the right against the hydraulic pressure in the space 25 and hold the friction member 20 in a disengaged state with respect to the inner surface of the converter cover 3, the lock-up clutch 19 is moved between the converter cover 3 and the lock-up clutch 19 Means is provided for introducing hydraulic pressure into the space 28 between. This means consists of a passage 29 formed axially in the input shaft 11 and communicating with the space 28 from the end of the input shaft 11 . Hydraulic pressure may be supplied to the passage 29 by a known control circuit (not shown) (for example, the one described in JP-A-54-132062). Upper friction member 20
is disengaged from the inner surface of the converter cover 3, and the lock-up clutch is released. If lock-up is desired depending on conditions such as vehicle speed and load, the hydraulic pressure in the space 8 between the converter cover 3 and the lock-up clutch 19 is eliminated,
The lock-up clutch 19 is pushed to the left by the hydraulic pressure in the space 25, and the friction member 20 engages the inner surface of the converter cover 3. As a result, the pump impeller of the torque converter and the turbine runner are mechanically directly connected.

In the above-described embodiments of the invention, the turbine hub 10
Since the outflow passage 27 is formed in the space 26 as described above, and the centrifugal valve 30 is open when the turbine runner 8 is stopped, the hydraulic fluid between the turbine runner and the lock-up clutch 14 is always kept in the space 26. It is discharged and a flow is formed through the space 25 as indicated by the dotted arrow. Therefore, even if the torque converter is in a stall state and the pressure in the space 25 shows an increasing tendency, the pressure is relieved because it is released through the outlet passage 27, and no excess pressure is generated in the space 25. , the lock-up clutch 19 is pushed to the left against the pressure in the space 28, eliminating the risk of clutch drag. Further, since the centrifugal valve 30 closes when the turbine runner 8 rotates at high speed, the hydraulic pressure necessary for lock-up can always be secured in the space 25.

[Brief explanation of the drawing]

The drawing is a sectional view of a lock-up torque converter showing an embodiment of the present invention. 3...Converter cover, 4...Pump impeller shell, 6...Pump impeller blade, 8
... Turbine runner, 11 ... Input shaft, 19 ...
Lockup clutch, 25... Space, 27...
Outflow path, 30... centrifugal valve.

Claims (1)

[Claims] 1 In a converter chamber, one end surface of which is covered by a converter cover and the other end surface of which is covered by a pump impeller that rotates integrally with the converter cover,
A turbine runner is arranged to face the pump impeller, and a lock is provided between the converter cover and the turbine runner, which can rotate together with the turbine runner and can move in the axial direction to frictionally engage the converter cover. A lock-up clutch is provided for retaining the lock-up clutch in a released position by introducing hydraulic pressure between the converter cover and the lock-up clutch and for locking up by discharging the hydraulic pressure. In a conventional lock-up torque converter, an outflow path is formed to allow oil in a space between the turbine runner and the lock-up clutch to flow out to the outside, and this outflow path opens when the torque converter stalls to prevent the high-speed rotation of the turbine runner. A lock-up torque converter characterized by being equipped with a centrifugal valve that closes when