GB2145198A

GB2145198A - Hydrodynamic coupling

Info

Publication number: GB2145198A
Application number: GB08418757A
Authority: GB
Inventors: Jacques Duminy
Original assignee: Voith Turbo GmbH and Co KG
Current assignee: Voith Turbo GmbH and Co KG
Priority date: 1983-08-18
Filing date: 1984-07-23
Publication date: 1985-03-20
Also published as: JPS6065916A; GB8418757D0; GB2145198B; DE3329854C1

Abstract

The filling level in the working chamber (13) of a hydrodynamic coupling can be varied due to the fact that rotating with the primary vane wheel (10) there is a storage container (15) for working fluid which can be transferred between this storage container and the working chamber by controlling admission of a compressed gas into the storage chamber. The storage container surrounds the radially outer region of the working chamber, and, in one case, is connected to the working chamber via at least two different fluid lines (28, 38). One (drainage) line (28) is designed for a constant flow of fluid from the working Fig. 2 chamber to the container, whilst the other (filling) line (38) is designed for a constant flow of fluid from the storage container to the working chamber, brought about by the pressure of the compressed gas. In another case, a fluid line (18) extends in the radial direction from said radially outer region into a fluid ring (16) formed, in operation, in the storage container (15), and means are provided for superimposing a pulsating pressure onto the compressed gas set pressure. <IMAGE>

Description

SPECIFICATION A hydrodynamic adjusting coupling The invention relates generally to a hydrodynamic adjusting coupling of the kind having a primary vane wheel and a secondary vane wheel which together form a toroidal working chamber which can be filled with working fluid. The filling level in the working chamber can be varied due to the fact that, rotating with the primary vane wheel, there is a storage container for working fluid out of which more or less working fluid is conveyed into the working chamber by means of compressed air. The coupling slip (the relationship between the primary rotary speed and the secondary rotary speed) can be varied in this way.

The state of the Art is generally represented by the following publications: 1. German Laid-Open Patent Specification 1 625 700.

2. German Patent Specification No. 594 106.

3. U.S. Patent Specification No. 2 416 311.

A hydrodynamic adjusting coupling with the features listed in the preamble to Patent claim 1 is known from publication 1. In this, as with the subject of publication 2, the storage container is arranged axially adjacent to the working chamber. Compressed air has to be supplied via two different pipeline systems, either into the storage container when the filling level in the working chamber is to be raised, or into the working chamber when the filling level in the working chamber is to be reduced. As long as the filling level in the working chamber remains unchanged, cooling of the working fluid located in the working chamber can occur only by transfer of heat to the shell (rotating with the primary vane wheel) and from there to the ambient air.

It is known from publication 2 that the working fluid can also be conducted from the working chamber into the storage container without supplying compressed air to the working chamber, i.e.

solely by making use of kinetic energy. However, it is not possible in this case to achieve complete draining of the working chamber in this manner.

It is known from publication 3 for the storage container to surround the radially outer region of the working chamber. In this case, the working chamber is connected to the storage container via spray holes 1 8a for the purpose of draining. A non-rotating scoop-pipe is provided for controlling the filling level in the working chamber, dipping more or less deeply into the ring of fluid located in the storage container.

The object of the invention is to develop the hydrodynamic adjusting coupling defined in the preamble to claim 1 so that the following requirements are fulfilled: 1. it should be possible to control the coupling for less outlay than hitherto; 2. it should be possible to drain it completely, when required; 3. the amount of heat removed from the fluid located in the working chamber should be more than the amount removed hitherto, so that the coupling can transmit more power.

This object is achieved with the features listed in the characterising clause of claim 1.

According to the invention only one controllable supply device for compressed air need be provided; this determines the pressure in the storage container and thereby the filling level in the working chamber.

Due to the arrangement of the annular storage container round the outside of the working chamber, a flow of fluid from the working chamber into the storage container can take place in a known way, without compressed air being supplied to the working chamber. There is also the possibility of draining the working chamber completely. At the same time, according to the invention a coupling which is very short in the axial direction is obtained, which is necessary for many applications.

In addition, with the invention a constant interchange of fluid between the working chamber and the storage container occurs while the coupling is operating, without the use of a scoop-pipe. This means that the relatively large surface area of the storage container is available for conducting heat from the active part of the working fluid to the surroundings. If desired, this surface area can be further increased by fins or the like.

According to claim 1 at least one drainage line and at least one filling line are provided.

The entrance into the drainage line can be constructed either according to claim 2 or according to claim 3. In order to ensure that compressed air does not reach the working chamber via the drainage line it is expedient to arrange the discharge outlet of the drainage line inside the ring of fluid located in the storage container (claim 4). Naturally, the inlet opening into the filling line must also be arranged therein. The outlet from the filling line can preferably be constructed according to claim 5.

In claim 6 another solution to the problem is given.

Again there is only one controllable supply device for compressed air connected to the storage container. Also, again the annular storage container is arranged round the outside of the working chamber.

Differing from the subject of claim 1, there is only one connecting line between the working chamber and the storage container, connecting the radially outer region of the working chamber with the radially outer region of the storage container. Naturally, more fluid lines of this kind can also be distributed round the circumference of the coupling.

However, they are then all uniform in construction.

Through each of these fluid lines the working fluid flows either towards the working chamber or back towards the storage container, depending on whether the static pressure set in the storage container is greater or less than the dynamic pressure inside the fluid line or lines. With this design, circulation of fluid between the working chamber and the storage container can also be obtained for the purpose of cooling the active portion of the fluid: For this, steps are taken so that the air pressure in the storage container pulsates slightly all the time, i.e. a pulsating pressure is superimposed on the operating pressure which has been set.By this means small surges of heated working fluid are constantly being conveyed from the working cham ber into the storage container, and in between these surges equally small surges of cooled working fluid are conveyed from the storage container into the working chamber.

In order to avoid a permanent increase of the air counter-pressure in the working chamber and in the so-called pressure head chamber (which is located radially inside the working chamber) when filling the working chamber, an air-venting line can be provided. It is advantageous to provide a centrifugal valve in this air-venting line, as indicated in claim 7, so that when the coupling is being run-up (i.e. as long as there is still working fluid in the pressure head chamber) no working fluid reaches the outside via the air-venting line.There are two possibilities for the arrangement of the centrifugal valve, depending on the structural designof the coupling and particularly that of the pressure head chamber: either the centrifugal valve is arranged in the coupling shell which rotates with the primary vane wheel, or the centrifugal valve is arranged in the vicinity of the hub of the secondary vane wheel and the air-venting line is passed through the secondary hub or secondary shaft to the outside. In the first case, the centrifugal valve opens at a specific primary rotary speed at which it is established that the working fluid has been distributed in a ring in the storage container. In the secondcase, the centrifugal valve does not open until a specific secondary rotary speed has been reached. This way it can be more reliably ensured that there is no more working fluid in the pressure head chamber.

Embodiment examples of the invention are described in the following with reference to the drawing.

Figure 1 shows a coupling, largely in longitudinal section.

Figure 2 shows an embodiment which differs from that in Figure 1, entirely in longitudinal section.

Figure3shows a section, on a largerscalethan in Figures 1 and 2, through the centrifugal valve on the air-venting line.

Figure 4 shows a different arrangement of the centrifugal valve on the air-venting line from that shown in Figures 1 to 3.

The main components ofthe hydrodynamic adjusting coupling shown in Figure 1 are a primary vane wheel 10 with a drive flange 11 integral with it and a hollow drive shaft 9 attached thereto; there is also a secondary vane wheel 14 which forms a toroidal working chamber 13 in conjunction with the primary vane wheel 11 and which is surrounded by a shell 12 attached to the primary vane wheel. The secondary vane wheel 14 is attached to an output shaft 8 which is mounted by means of roller bearings 7 in the primary-side parts 10 and 12 of the coupling.

Atop part 19 also adjoins the shell 12, and in conjunction with the drive flange 11 defines an annular storage container 15. The latterthus surrounds the radially outer region of the working chamber 13, or in other words, the working chamber 13 lies concentrically inside the annular storage container 15.

In the stationary state the working fluid (e.g. oil) is located in the lower region of the storage container 15 and the working chamber 13, most of it being in the storage container 15. When the primary side 9 to 12 and 15 is being run up, the oil is flung out into the radially outer region of the storage container 15 where it forms a ring 16 of oil.

If pressure medium (e.g. compressed air) is then supplied to the storage container 15 the static pressure at the inner radius of the oil ring 16 rises.

This causes some of the oil to pass through the connecting duct 18 which rotates with the primary vane wheel 10, into the working chamber 13. This process continues until the working chamber has filled with oil sufficently for equilibrium to be established between the static pressure in the storage container 15 and the dynamic pressure which is produced in the oil located in the connecting duct 18 by the meridian flow (arrow M).

The amount of oil which passes into the working chamber 13, and thus the amount of coupling slip, are influenced by the pressure in the storage container 15, that is, by the pressure of the compressed air being supplied. By changing the air pressure, correspondingly different states of slip can be established. If the air pressure is reduced or eliminated completely, some or all of the oil, respectively, flows through the duct 18 back into the storage container 15.

The connecting duct 18 preferably extends in a radial direction from the radially outer region of one of the vane channels of the primary vane wheel 10 to the radially outer region of the storage container 15.

If required, a plurality of such connecting ducts 18 can be provided, distributed around the circumference of the primary vane wheel.

Since the heat produced during slip operation can be conducted away only via the surface of the coupling, the following measures are taken to increase the amount of heat which can be conducted away: The circulation of oil between the hot oil in the working chamber 13 and the somewhat cooler oil ring 16 is brought about by gently pulsing the air pressure (pulsating pressure is superimposed on the operating pressure). In addition to this, cooling fins can be provided on the outer area of the storage container 15; these have not been shown in the drawing.

Another method for producing a circulation of oil between the working chamber 13 and the storage container is used in the embodiment shown in Figure 2, in which the important parts remain the same as in Figure 1. Only the connecting ducts 28 and 38 are different from those (18) in Figure 1. In particular, the connecting ducts 28 and 38 have different shaping. One 28 of the connecting ducts which is now used exclusively as a drainage line, i.e.

for conveying fluid from the working chamber 13 to the storage container 15, is designed substantially exactly the same as the one in Figure 1. The only difference is that instead of an integral duct 18 a piece of pipe 28 is inserted in the primary vane wheel 10. The inlet end projects slightly into the relevant vane channel and points more decidely counter to the meridian flow M than in Figure 1. The other connecting duct 38 which is used exclusively as a filling line, i.e. for conveying fluid from the storage containe 15 to the working chamber 13, also extends in the radial direction. However, the end projecting into the relevant vane channel is bent in the other direction from that of the duct 28, namely, so that the direction of the outlet opening corresponds at least substantially with the direction of the meridian flow M.

The annular pressure head chamber 20 located between the working chamber 13 and the output shaft 8 is connected to the surrounding area (which is generally at atmosphere pressure) via a valve 21 actuated by centrifugal force and an air-venting line 22 (which can also serve as an air inlet line). The valve 21 is attached to the output shaft 8. As can be seen in Figure 3, it has a spherical valve body 23 which is pressed onto a valve seat by a compression spring 24 in the direction of the axis of rotation of the coupling. When a specific secondary rotary speed is reached (after the ru n n ing-u p process) the valve 21 opens so that the air counter-pressure which has built up in the working chamber 13 and in the pressure head chamber 20 during the running-up process is reduced.

Figure 4 shows the air being vented via a bore 40 in the secondary vane wheel 14 and via a centrifugal valve 41 which is arranged in the shell 12 on the primary side. This allows the long ducts 22 which have to be provided in the output shaft 8 in the case shown in Figure 3 to be dispensed with.

Claims

1. A hydrodynamic adjusting coupling of the kind having a primary vane wheel and a secondary vane wheel which together form a toroidal working chamber which can be filled with working fluid, and having the following features; (a) an annular storage container for working fluid and a shell surrounding the secondary vane wheel which rotate with the primary vane wheel; (b) at least one fluid line which rotates with the primary vane wheel extending from the radially outer region of the working chamber into the storage container, (c) a supply line for gaseous pressure medium (e.g. compressed air) connected to the storage container for initiating the flow of fluid from the storage container into the working chamber, characterised by the following features:: (d) the storage container surrounds the radially outer region of the working chamber; (e) the radially outer region of the working chamber is connected to the storage container via at least two different fluid lines comprising (e1) a drainage line which is designed for a constant flow of fluid from the working chamber to the storage container, using the kinetic energy of the fluid located in the working chamber; and (e2) a filling line which is designed for a constant flow of fluid from the storage container to the working chamber, brought about by the pressure in the storage container.

2. Acoupling according to claim 1, characterised in that the inlet into the drainage line is arranged in the radially outer region of a vane channel appertaining to the primary vane wheel and is directed counter to the meridian flow.

3. A coupling according to claim 1, characterised in that the inlet into the drainage line is arranged radially outside the secondary vane wheel on the shell and, in the manner of a rotating scoop-pipe, is directed in the direction of rotation of the primary vane wheel.

4. A coupling according to claim 2 or 3, characterised in that the discharge outlet of the drainage line is located in the radially outer region of the storage container; thus inside the ring of fluid which forms there.

5. A coupling according to any one of claims 1 to 4, characterised in that the outlet opening of the filling line is arranged in the radially outer region of a vane channel appertaining to the primary vane wheel and points in the direction of the meridian flow.

6. A hydrodynamic adjusting coupling of the kind having a primary vane wheel and a secondary vane wheel which togethe form a toroidal working chamber which can be filled with working fluid, and having the following features; a) an annular storage container for working fluid and a shell surrounding the secondary vane wheel which rotate with the primary vane wheel; b) at least one fluid line which rotates with the primary vane wheel extending from the radially outer region of the working chamber into the storage container; c) a supply line for gaseous pressure medium (e.g.

compressed air) connected to the storage container for initiating the flow of fluid from the storage container into the working chamber, characterised by the following features: d) the storage container surrounds the radially outer region of the working chamber; e) the fluid line extends approximately in the radial direction from the radially outer region of the working chamber into a fluid ring which forms in the storage container when the coupling is in operation; and, f) a device is provided which superimposes a pulsating pressure on the set pressure of the gaseous pressure medium.

7. A coupling according to claim 1 or 6, and having an air pipeline which is connected to the radially inner region of the working chamber, characterised by a valve which automatically controls the air pipeline, said valve opening automatically under centrifugal force at a specific rotary speed.

8. A coupling according to claim 7, characterised in that the valve is arranged to rotate with the primary vane wheel.

9. A coupling according to claim 7, characterised in that the valve is arranged to rotate with the secondary vane wheel.

10. A hydrodynamic adjusting coupling constructed, arranged and adapted to operate substantially as hereinbefore described with reference to, and as shown in, the accompanying drawing.