DE10039836A1 - Ventilation device for automatic motor vehicle transmissions has rectangular sealing rings on shafts, with groove-like ventilation apertures generating pump action - Google Patents

Abstract

The transmission has rectangular sealing rings for coupling resp. brake, on shafts in the primary oil circuit. The rings (2) have ventilation apertures (6) e.g. grooves, in the radial circumference, which generate a pump action during rotation of shaft (1) or rectangular ring. The grooves are positioned at an angle to the longitudinal shaft axis.

Description

The present invention relates to an arrangement for Ventilation of rotating clutches or stationary brakes, with oil supply via a rotating shaft, in automatic transmission ben of motor vehicles.

In the primary oil circuit of automatic transmissions is constant a small amount of air due to foaming of the oil the. This air also migrates into the pressure channels of Schalt elements and forms larger air poles at certain points art. When loading such a switching element with Pressure oil comes from the compressibility of the air pole sters to a delayed build-up of pressure, which also increases Oscillation tends.

From the patent application DE-A 38 30 829 by the applicant is an apparatus and method for venting hydraulically actuated brakes, especially for automats gearboxes of motor vehicles known. This registration works assume that coupling spaces and feed channels are hydraulic switchable clutches and brakes in non-switched Condition at least partially empty. With a switch the feed channels and coupling spaces of the Clutches and brakes suddenly filled with oil, whereby the air in the clutch compartment is compressed. The Air pockets created as a result are only included increasing pressure during the switching process via a Ent ventilation valve at least partially dismantled, whereby the vent valve at the beginning of the switching process a spring force is open and in the course of pressure build-up is automatically shut off by this.  

The air pockets in the clutch compartments and in ih Ren feed channels have the disadvantage that scatter caused in the build-up of pressure, which is not one ensure that the clutch shifts properly. Insbeson brakes and rotating clutches, the pressure in switched state is regulated, the controllability due to the air pockets due to the high compressibility air are severely affected.

The changes in the pressure profiles which affect the Impact shifting comfort arise from overlay damping properties of volume damper and com compressibility of air pockets. With a rotation of the Coupling takes off the oil-air emulsion that is fed through in Small air bubbles contained in the pressurized oil The rotational movement flows into the clutch chamber. The air contained in the rotating emulsion centrifuge partially or completely and accumulates on Inner diameter of the clutch space.

To avoid these disadvantages, the patent message DE-A 198 44 376 from the applicant a device for Bleeding of hydraulically actuated clutches is recommended beat, which is that between the clutch space and a compensation space in the transmission at least one Connection for removing air pockets from the dome lungsraum is provided, which is a throttle device and / or has a shut-off device. That too therein proposed methods for venting hydrau Couplings that can be actuated are that during a supply of pressure oil in the clutch chamber of this is vented in such a way that air pockets over at least  a connection from the clutch compartment into a compensation space in the gearbox.

In order not only for hydraulically actuated clutches, but in general with non-vented rotating Pressure rooms, e.g. B. in addition to the known couplings also Va drives for continuously variable automatic transmissions, so-called CVT Gearboxes or hydrodynamic converters that are related with automatic transmissions for motor vehicles and which are pressurized with a pressure medium, the Bil formation of emulsions or dispersions from air and oil prevent was already in the German patent application P 199 33 470 of the applicant a device for ver improvement of the filling of rotating pressure rooms with Pressure oil proposed, the rotating pressure chambers with a supply line for the pressure oil are provided. The ro The pressure chamber is equipped with a ventilation line hen, the inlet opening on the inside diameter of the rotate the pressure chamber or on the inside diameter of the rotating one Part of the feed is arranged, the outlet opening in a ventilation room opens into a panel or a controlled valve can be used.

Through the well-known ventilation holes in ventilation dazzle and / or vent valves, it is possible to To prevent air cushions to a large extent and thus to achieve comparable filling states of the switching elements. However, a disadvantage of these ventilation systems is still the additional component and manufacturing effort with the associated higher costs, as well as the risk of ver blockages and possibly the total failure of a valve.

The object of the present invention is a Ent ventilation arrangement for rotating couplings or standing Brake with oil supply via a rotating shaft in the automat driven by motor vehicles to propose without additional manufacturing costs can be realized, so that Costs can be reduced.

Starting from an arrangement of ge closer named kind the solution of this task with the in Claim 1 specified features. Advantageous design are described in the subclaims.

The invention is based on an arrangement Bleeding rotating clutches or rotating brakes with oil supply via a rotating shaft, whereby sealing rings for the clutches or brakes on shafts in primary oil circuit in the form of rectangular rings are provided. he According to the invention, the venting function is now provided in the sealing ring designed as a rectangular ring and thus the air cushion created in the pressure channel targeted mining. For this, the rectangular ring is on the radial Provide circumference with ventilation recesses that so are dimensioned to have a pumping action when the shaft rotates or the sealing ring. This pumping action takes away increasing speed. The ventilation cutouts are provided on the radial circumference of the rectangular ring and can have a constant cross section over their length or have a variable cross-section over their length or but from a diffuse surface structure on the whole th surface of the radial circumference of the rectangular ring consist.

In the following the invention with reference to the drawing explained in more detail in the advantageous embodiments are shown.

Show it:

Fig. 1 shows a rectangular ring designed according to the invention, which is arranged on a rotating shaft and

Fig. 2 to 5 different embodiments for the design of the ventilation recesses on the radial circumference of the rectangular ring.

Automatic transmission for motor vehicles with rotating Clutches or standing brakes with oil supply via a rotating shaft are well known to those skilled in the art, so in following only those necessary for understanding the invention components described and shown in the drawing are.

Fig. 1 shows a arranged on a rotating shaft 1 rectangular ring 2 , the depressurized side of the clutch or brake with 5 and the pressure side with 4 be distinguished. 3 denotes an oil supply channel provided in the shaft 1 . The rectangular ring 2 radially seals the pressure side 5 against a bore 8 .

The arrangement for ventilation is now integrated according to the invention in the rectangular ring 2 in order to specifically reduce the air cushion created on the pressure side 4 . For this purpose, the rectangular ring 2 is provided on the radial circumference with ventilation cutouts 6 , which achieve a pumping action when the shaft or the rectangular ring rotates. This pumping effect increases with increasing speed.

This permanent minimum volume flow of the oil through the ventilation recess 6 prevents an air cushion from building up in the oil supply channel 3 for switching elements. As a result, reproducible filling conditions are created without additional manufacturing effort.

The volume flow V, which is a result of the venting 6 saving is a function of ΔP, the flow cross section, the dynamic portion by Eigenpumpwir effect as a function of the speed, the oil viscosity and the oil temperature. By selecting the cross-sectional size and cross-sectional geometry as well as the number and arrangement of the ventilation cutouts, an optimum of leakage and ventilation effect can be set.

It should be noted that the relative movement of the seal ringes is a function of the oil pressure and that this with increasing oil pressure drops. This also changes the Self-pumping effect of the sealing ring with falling relative movement supply.

In the embodiment shown in Fig. 1, the ventilation recesses 6 (only one of which is shown in the drawing) are formed in the form of grooves with constant cross-section, which extend at an angle to the longitudinal axis of the shaft 1 .

In the exemplary embodiment shown in FIG. 2, the rectangular ring is again designated with 2 and a groove-shaped ventilation cutout 6 , which has a constant cross section, which is larger here than that of the cutout 6 in FIG. 1. The groove 6 also runs here under another Angle.

In the embodiment shown in FIG. 3, the groove 6 'in the rectangular ring 2 has a variable cross section over its length, with an expanding vent opening on the unpressurized side.

In the embodiment shown in FIG. 4, the venting recesses are designed as a diffuse surface structure 6 ″, which are distributed over the entire radial circumference of the rectangular ring 2 .

In the embodiment shown in Fig. 5, the rectangular ring is formed as a compound ring (compound ring), that is, it consists of two different materials 2 ', 2 ", which have different thermal expansion coefficients, so that when two different cross-sections of the groove-shaped venting recess 6 '''(which run parallel to the longitudinal axis of the shaft 1 here), a venting behavior which can be changed as a function of the temperature can be set.

The usually with such rectangular rings diagonally executed separating gap of the rectangular ring for assembly of the ring on the rings is required in the Drawings not shown. The gap width of this separation column is usually designed so that it Operating temperature of the gearbox or the one to be sealed Oil, which is approximately 90 ° C depending on the design, due to the thermal expansion coefficient becomes zero.  

reference numeral

1

wave

2

rectangular ring

3

Oil supply channel

4

pressure side

5

unpressurized page

6

venting opening

7

drilling

Claims (7)

1. Arrangement for venting rotating clutches or stationary brakes, with oil supply via a rotating shaft, in automatic transmissions of motor vehicles, sealing rings for the clutches or brakes on shafts in the primary oil circuit in the form of rectangular rings are provided, characterized in that the right Corner rings ( 2 ) are provided on the radial circumference with ventilation recesses ( 6 ), which are dimensioned such that a pumping action occurs when the shaft ( 1 ) or the rectangular ring ( 2 ) rotates. 2. Arrangement according to claim 1, characterized in that the ventilation recesses ( 6 ) are grooves. 3. Arrangement according to claim 2, characterized records that the grooves have a constant cross cut across their length. 4. Arrangement according to claim 2, characterized records that the grooves have a variable Have cross-section over their length. 5. Arrangement according to claim 4, characterized records that the cross section in the direction of pressure loose side increases.   6. Arrangement according to one of the preceding claims, characterized in that the grooves are arranged at an angle to the longitudinal axis of the shaft ( 1 ). 7. Arrangement according to claim 1, characterized in that the ventilation recesses from a diffuse surface structure ( 6 ") on the entire surface of the radial circumference of the rectangular ring hen.