The invention relates to a lubrication device transmission device comprising friction elements with a flexible element in between for coupling and transmitting engine power to wheels of a vehicle by actuation of the friction elements. Such a transmission usually comprises a primary friction element, such as pulleys, mounted on an input shaft, connected to a power source, and a secondary friction element, such as pulleys, mounted on a secondary shaft. Between the primary friction element and the secondary friction element, a flexible element is provided. Due to actuation of the friction elements, the friction elements are adjusted with respect to each other on their respective shaft and the clamping of the flexible element may be varied. Depending on the clamping of the flexible element, more or less power may be transmitted to the output shaft of the transmission. The flexible element can be embodied as a belt or a chain and can be clamped by means of friction force. An example of such a transmission is a continuously variable transmission having a belt as a flexible element, and pulleys as friction elements.

During use, lubrication of the flexible element and/or the friction elements is required, and often prescribed by the supplier of the flexible element. Also, during use, cooling of the flexible element and/or the friction elements may be required. To provide for cooling and/or lubrication, a lubrication device is provided for the transmission device. Such a lubrication device is typically mounted to the transmission housing where it connects with the lubrication circuit. A lubrication device is important to the functioning of the transmission, as without the lubrication and/or cooling, the transmission may go into failure. Since a lubrication device is operated in a relatively harsh environment of the transmission, with relatively high temperatures and/or relatively high vibration, lubrication devices are often of a rather robust design.

Known prior art lubrication devices typically have a pipe body comprising a lubrication liquid entry connectable to the lubrication circuit, and at least one radial lubrication liquid exit, arranged to spout a

lubrication liquid on a belt and/or a pulley of the transmission system, for example of the continuously variable transmission system. A pipe body of such a prior art device is typically made of metal and generally has a straight body. Some lubrication devices have an S- shaped pipe body.

An important disadvantage of such prior art devices is that they relatively take up a lot of space within a transmission system, in particular in a CVT. There may not always be sufficient space to mount a straight lubrication pipe to the transmission device to provide radial exits at the required locations. Thereto, lubrication devices having an S-shaped pipe body are known to provide radial exits at the required locations within space constraints of the transmission. However, these S-shaped lubrication devices may be relatively complicated and expensive to produce, and may not provide an optimal lubrication pressure due to the bended pipe body.

It is an aim of the present invention to solve or alleviate one or more of the above-mentioned problems. Particularly, the invention aims at providing an improved and efficient lubrication device which takes up relatively little space in the transmission system. It is furthermore an object of the invention to provide a lubrication device which is relatively easy to produce. The invention also aims at providing a relatively inexpensive lubrication device.

To these aims, according to a first aspect of the present invention, there is provided a lubrication device for a transmission system having an endless transmission element wherein a pipe body comprises a lubrication liquid entry connectable to a lubrication liquid supply source, and at least one lubrication liquid exit, arranged to spray a lubrication liquid on said endless transmission element and/or a pulley of said transmission system, wherein at least a distal end part of said pipe body is tilted with respect to a proximal part of said pipe body. As the total height of the pipe body, measured in a direction perpendicular to a plane formed by the lubrication liquid entry, is smaller for a pipe body having a tilted distal end part with respect to the lubrication liquid entry than for a conventional, straight, lubrication device without tilt, the lubrication device according to the invention takes up relatively little space in the transmission system.

Furthermore, said lubrication device is relatively easy to produce, and therefore relatively inexpensive.

It is preferred that an angle between a central axis of said proximal part of said pipe body and a central axis of said distal end part of said pipe body may be comprised in a range of approximately l ^° -45 ^° , preferably in a range of approximately 5 ^° -30 ^° , for example approximately 10 ^° -15 ^° . Such an angle allows a decrease in height of the lubrication device measured in a direction perpendicular to a plane formed by the lubrication liquid entry, which is sufficient for the lubrication device to take up less space in the transmission device, while still being acceptable in terms of constructional and/or material constraints with respect to the proximal part of said pipe body.

In a preferred embodiment, said pipe body can comprise a straight liquid channel extending between said lubrication liquid entry and said at least one lubrication liquid exit. A straight liquid channel is less prone to wear due to the lubrication liquid's pressure on the inside channel wall. At the same time, a straight liquid channel is easier and thus cheaper to produce. Alternatively, the liquid channel can also comprise one or more twists between straight channel parts. The liquid channel can also comprise one or more bends, or be an entirely bended channel.

In a more preferred embodiment, said liquid channel may substantially have the shape of an oblique cylinder. As a consequence, parallel cross- sections of the liquid channel are the same over the channel's entire length, which leads to a constant pressure in the liquid's flow in the channel. Alternatively, said liquid channel might have a conical shape, with a liquid channel widening or narrowing in a downstream direction.

Said lubrication liquid entry can advantageously be an axial lubrication liquid entry, preferably at said proximal part of said pipe body, which improves the lubrication liquid's flow into the liquid channel of the pipe body. A radial lubrication liquid entry is a possible alternative.

More advantageously, said at least one lubrication liquid exit can be a radial lubrication liquid exit. A radial lubrication liquid exit simplifies the adaptation of the lubrication liquid spray's direction, adaptable over 360 ^° , to the desired location, for example to a belt or a pulley of the transmission system.

Said at least one lubrication liquid exit may preferably be axially spaced-apart from said at least one lubrication liquid entry, so as to take advantage of the pipe body's length to come closer to the location which needs to be lubricated.

In a preferred embodiment, said pipe body can comprise at least two lubrication liquid exits. In this way, more than one pulley can be lubricated by the same lubrication device, or a same pulley can be lubricated at more than one location. Said at least two lubrication liquid exits may preferably be radially and/or axially spaced-apart. A radial spread of lubrication liquid exits can for example be advantageous in case of simultaneous lubrication of more than one pulley, whereas an axial spread of lubrication liquid exits may for example serve for lubricating a same pulley at different locations. The same is valid for the lubrication of an endless transmission element, such as a belt. A combination of radially and axially spaced-apart lubrication liquid exits may combine the above- mentioned advantages. It is more preferred that said at least one radial lubrication liquid exit is a nozzle radially protruding from said pipe body. A radially

protruding nozzle allows a longer exit tube than an exit hole in a peripheral wall of the pipe body, thus improving the direction of the lubrication liquid spray and preventing diffusion of said lubrication liquid spray.

Alternatively, the pipe body may comprise a cylindrical thickening at the lubrication liquid exit's height, with or without an intermediate liquid chamber, to obtain a similar effect.

In an advantageous embodiment, the lubrication device can comprise a fixation member arranged to fix the device to a housing of the transmission system, thus providing a supplementary hold on top of a connection with a lubrication liquid supply source in order to improve the device's stability in the transmission system, which can be subject to high mechanical stress.

In a more advantageous embodiment, said fixation member may be an asymmetrical flange comprising a hole. The asymmetrical flange can provide a solid fixation of said pipe body, for example via a bolt passing through the flange's hole, without hindering an efficient connection of said pipe body with a lubrication liquid supply source.

In a still more advantageous embodiment, said fixation member can be located near a lubrication liquid entry of said pipe body, for example at a quarter or less of an axial length of said lubrication device from said axial lubrication liquid entry. Such a fixation location allows a relatively long extension of said pipe body towards the transmission system to be lubricated.

It may be preferred that at least one rib axially extends along said pipe body, preferably along a downstream or distal part of said pipe body, to support said pipe body. Such a rib can provide the pipe body with a supplementary strengthening. More preferably, said at least one rib axially widens up to said flange. In this way, the flange can provide a supplementary support to said tilted pipe body via said at least one rib.

In a preferred embodiment, said lubrication liquid entry of said pipe body is connectable to said lubrication liquid supply source via a press- fit connection. A press-fit connection is an easy-to-use connection, which is at the same time relatively easy and relatively cheap to produce, while it does provide a solid and liquid-tight connection. Alternatively, other connections, which are known per se by a person skilled in the art, may be used, for example a threaded connection or a conical connection.

On a more preferred embodiment, said lubrication device is at least partly, preferably substantially entirely, made of a thermoplastic polymer, for example of a glass fibre reinforced high temperature resistant grade. Such a polymer can provide a pipe body which is fluid-tight and strong enough for a relatively harsh environment in which it is used. At the same time, it is relatively easy to produce. The use of a thermoplastic polymer for a lubrication device may also be considered as an independent invention, providing important advantages over the known use of metal for a

lubrication device. A thermoplastic polymer is relatively easy to mould and can provide a relatively light-weight lubrication device The production line of the lubrication device can also be easily adapted to the use of another plastic material if needed. More preferably, said lubrication device is made by injection moulding, which allows a relatively easy production of a large amount of said lubrication devices, preferably completely moulded in one piece.

Said transmission system may preferably be a continuously variable transmission system, which provides an infinite number of possible transmission ratios, and can therefore optimize performance and fuel consumption. It is also a relatively small transmission system. Alternatively, the lubrication pipe according to the invention can also be used in other gearbox types as long as forced lubrication is needed.

According to another aspect of the invention, there is provided a lubrication device characterized by the features of claim 20.

According to another aspect of the invention, there is provided a transmission system having an endless transmission element comprising a lubrication device showing one or more of the above-mentioned features.

According to yet another aspect of the invention, there is provided a method for producing a lubrication device for a transmission system having an endless transmission element characterized by the features according to claim 22. These further aspects of the invention can provide one or more of the above-mentioned advantages.

Further advantageous embodiments are represented in the subclaims.

The invention will further be elucidated on the basis of exemplary embodiments which are represented in a drawing. The exemplary

embodiments are given by way of non-limitative illustration.

Figure 1 shows a transmission system including an embodiment of a lubrication device according to the invention;

Figure 2 shows a side view of a first embodiment of a lubrication device according to the invention;

Figure 3 shows a cross-section of a second embodiment of a lubrication device according to the invention;

Figure 4 shows a perspective bottom view on the lubrication device of Figure 2;

Figure 5 shows a perspective top view on the lubrication device of

Figure 2.

It is noted that the figures are only schematic representations of embodiments of the invention that are given by way of non-limiting example. In the figures, the same or corresponding parts are designated with the same reference numerals.

Figure 1 shows a transmission system including an embodiment of a lubrication device according to the invention. Said transmission system preferably is a continuously variable transmission system. Such a

transmission system usually comprises a primary friction element, such as a pulley 1, mounted on an input shaft 2, connected to a power source (not shown), and a secondary friction element, such as a pulley 3, mounted on a secondary shaft 4. Between the primary pulley 1 and the secondary pulley 3, a flexible element, i.e. an endless belt 5, is provided. The flexible element can also be embodied by a chain. Due to actuation of the pulleys in the direction of the arrow A, the pulleys are adjusted with respect to each other on their respective shafts, and the clamping of the endless belt may be varied. Depending on the clamping of the endless belt, more or less power may be transmitted to the output shaft of the transmission. During use, lubrication of the endless belt and/or the pulleys is required, and often prescribed by the supplier of the endless belt. Also, during use, cooling of the endless belt and/or the pulleys may be required. To provide for cooling and/or lubrication, a lubrication device 6 is provided for the transmission device. The arrow B indicates the direction into which the lubrication device 6 can spray a lubrication liquid, for example oil, in particular towards a location where the endless belt 5 will be engaging a pulley 3. The arrow C indicates the direction into which the lubrication device 6 can spray a lubrication liquid in case of an inverse ratio of transmission between both pulleys 1 and 3.

Figure 2 shows a side view of a preferred embodiment of a lubrication device according to the invention. The lubrication device 6 comprises a pipe body 7 with a lubrication liquid entry 8 connectable to a lubrication liquid supply source (not shown), and at least one lubrication liquid exit 9, arranged to spray a lubrication liquid on said endless transmission element 5 and/or a pulley 1, 3 of said transmission system, for example as in Figure 1. According to the invention, at least a distal end part 10 of said pipe body 7 is tilted with respect to a proximal part 11 of said pipe body 7. An angle a between a central axis 12 of a proximal part 11 of said pipe body 7 and a central axis 13 of said distal end part 10 of said pipe body 7 can be comprised in a range of approximately l°-45°, preferably in a range of approximately 5°-30°, for example be an angle of more or less 10° as in Figure 2. The angle is determined, among other parameters, by the available place in the transmission system, and by the direction into which a lubrication liquid has to be sprayed. The lubrication device can have a height H in a range of for example approximately 2-20cm, particularly approximately 5-10 cm.

The lubrication liquid entry 8 can be an axial lubrication liquid entry, preferably at said proximal part 11 of said pipe body 7. Alternatively, the proximal part 11 of said pipe body 7 could be a dead-end proximal part, and the lubrication liquid entry could be a radial entry, for example near the proximal part 11 of said pipe body. The lubrication liquid entry 8 of said pipe body 7 is connectable to a lubrication liquid supply source (not shown) via for example a press-fit connection, or any other suitable connection, preferably provided with an O-ring to prevent leakage of the lubrication liquid.

The at least one lubrication liquid exit 9, for example both liquid exits 9 of the embodiment in Figure 2, can be radial lubrication liquid exits. They are formed as a nozzle 14 radially protruding from said pipe body 7. The nozzle 14 can be made of the same material as the pipe body 7, or of a different material. The nozzle 14 can be produced simultaneously with the pipe body 7, or can be produced as an insert to be inserted on a separately made pipe body 7. The nozzle 14 can have a slight frustro-conical shape as in Figure 2, or another shape, for example a cylindrical shape. Instead of a lubrication liquid exit nozzle, a lubrication liquid exit can also be formed as a hole in the pipe body's wall, for example in a peripheral wall of said pipe body, which may or may not have been locally thickened. The at least one lubrication liquid exit 9 is preferably axially spaced-apart from said at least one lubrication liquid entry 8, for example being situated near a distal end part 10 of said pipe body 7, which distal end part 10 may be a dead-end part of said pipe body 7 (see also Figure 3). It is preferred for the pipe body 7 to comprise at least two lubrication liquid exits 9, as in Figure 2. In case of at least two lubrication liquid exits 9, they are preferably radially and/or axially spaced-apart.

Figure 3 shows a cross- section of a second embodiment of a lubrication device according to the invention. The pipe body 7 preferably comprises a straight liquid channel 15 extending between said lubrication liquid entry 8 and said at least one lubrication liquid exit 9. Said liquid channel 15 can substantially have the shape of an oblique cylinder. As a result of said straight liquid channel 15 within a pipe body 7, provided with a tilted distal end part 10 with respect to a proximal part 11, the lubrication liquid exit 8, which is located axially at the proximal end 11 of said pipe body 7, is slightly off-centred, as can be seen in Figure 4. Alternatively, the liquid channel 15 could also be in parallel with the outside pipe body and show a tilt or a bend.

The lubrication device can also comprise a fixation member 16 arranged to fix the device to a housing of a transmission system. Said fixation member 16 can be located near a lubrication liquid entry 8 of said pipe body 7, for example at a quarter or less of an axial length H (see also Figure 2) of said lubrication device from said axial lubrication liquid entry 8. In this embodiment, the fixation member 16 forms a separation between a rather small upstream part of the pipe body 7, and a main downstream part of said pipe body 7. The upstream part of said pipe body7 is perpendicular to a plane in which extends said fixation member 16, whereas the downstream part of said pipe body 7 is tilted with respect to the plane in which extends said fixation member 16.

Figure 4 shows a perspective bottom view on the lubrication device of Figure 2. In the preferred embodiment of Figures 2 and 4, said fixation member 16 is an asymmetrical flange comprising a hole 17. The hole 17 in the flange 16 is arranged to receive a fixation means, for example a bolt, to firmly attach the lubrication device to a housing of a transmission system.

Other fixation members are possible as well.

Figure 5 shows a perspective top view on the lubrication device of Figure 2. It is preferred that at least one rib 18 axially extends along said pipe body 7, preferably along a downstream part of said pipe body 7, to support said pipe body 7. The rib 18 can extend over an entire length of said pipe body 7, or just over a part of said pipe body, as for example in the preferred embodiment of Figure 5 showing two axial ribs 18, which preferably axially widen up to said flange 16. In this way, the fixation member 16 in the form of an asymmetrical flange also serves as a support to the tilted downstream part of said pipe body 7.

In an advantageous embodiment of the invention, which can also be considered as a separate invention, the lubrication device can at least partly, preferably substantially entirely, be made of a thermoplastic polymer, for example of a glass fibre reinforced high temperature resistant grade, in particular by injection moulding.

For the purpose of clarity and a concise description, features are described herein as part of the same or separate embodiments, however, it will be appreciated that the scope of the invention may include

embodiments having combinations of all or some of the features described.

It may be understood that the embodiments shown have the same or similar components, apart from where they are described as being different.

In the claims, any reference signs placed between parentheses shall not be construed as limiting the claim. The word 'comprising' does not exclude the presence of other features or steps than those listed in a claim. Furthermore, the words 'a' and 'an' shall not be construed as limited to Only one', but instead are used to mean 'at least one', and do not exclude a plurality. The mere fact that certain measures are recited in mutually different claims does not indicate that a combination of these measures cannot be used to an advantage.

It should be clear to the person skilled in the art that the invention is not limited to the embodiments described above. Many alternatives are possible within the scope of protection as formulated in the claims hereafter.