GB2594085A

GB2594085A - A gearbox

Info

Publication number: GB2594085A
Application number: GB2005590.1A
Authority: GB
Inventors: Redmond Dennis
Original assignee: Smart Manufacturing Technology Ltd
Current assignee: Smart Manufacturing Technology Ltd
Priority date: 2020-04-17
Filing date: 2020-04-17
Publication date: 2021-10-20
Anticipated expiration: 2040-04-17
Also published as: GB202005590D0; WO2021209741A1; GB2594085B

Abstract

A vehicle gearbox lubricant supply system has a pipe inlet 22 with a filter (44, figs 7 & 8) movable with a sump (14, fig 2). The inlet 22 is guided on rollers on parallel rails 28, with ends of the of the rails 28b, 28c higher to return the inlet to a middle of the rails aided by a fin (42, fig 6). A flexible or swivelling pipe (20, fig 2) is secured to the sump wall. Thus the inlet remains immersed on inclines, braking or accelerating.

Description

A gearbox

FIELD OF THE INVENTION

The present invention relates to a gearbox comprising a lubricant supply system, and to a lubricant filter for a lubricant supply system.

BACKGROUND OF THE INVENTION

It is known to use an injection lubrication system to lubricate the moving components of a gearbox or transmission of a vehicle. In such a system, lubricant, commonly lubricating oil, is held in a sump. Lubricant is pumped from the sump around the lubrication system, lubricating the gears and then returning to the sump for further circulation through the system. Lubricant is transferred from the sump to the remainder of the lubrication system via a pipe which extends within the sump. Such a pipe has an inlet end that is intended to be submersed within lubricant held within the sump. A filter is commonly positioned within the sump in order to filter debris from the lubricant before lubricant is circulated through the system.

When a vehicle with such a lubrication system is driven at an incline, i.e. climbing or descending a slope, lubricant held within the sump is displaced. Rather than remaining at a constant depth throughout the sump, lubricant is displaced to one end or the other of the sump. For example, as a vehicle is driven up a slope, the incline causes lubricant held within the sump to move towards the rear of the sump, i.e. to the end of the sump proximal the rear of the vehicle. If a vehicle is driven down a slope, lubricant held within the sump is moved towards the front of the sump, i.e. to the end of the sump proximal the front of the vehicle (and vice versa, if a vehicle is driven in reverse).

Similarly, when a vehicle is braked or accelerated, lubricant held within the sump is moved towards the front end of the sump or the rear end of the sump respectively.

As lubricant is moved from one end of the sump to the other in this way, and does not remain level within the sump, the inlet end of the pipe can become exposed, i.e. the inlet end is no longer immersed in the lubricant. This can lead to the pipe not drawing in enough oil to lubricate the gearbox, or the drawing in of air, both of which negatively affect lubrication of the system and can lead to damage of the lubricated components.

It is known to address this problem by having enough lubricant in the sump to ensure that the pipe inlet end does not become exposed but is constantly immersed in lubricant, no matter how the lubricant is moved around the sump. However, increasing the amount of lubricant in a lubrication system decreases efficiency, as churning losses are increased due to submersed gears moving through a greater amount of lubricant.

The present invention seeks to overcome or at least mitigate the problems of the prior art. SUMMARY OF THE INVENTION According to an embodiment there is provided a gearbox for a vehicle, the gearbox comprising a lubricant supply system, wherein the lubricant supply system comprises a lubricant sump configured to contain lubricant; and a pipe for transferring lubricant from the sump. The pipe comprises an inlet end for receiving lubricant from the sump, the inlet end of the pipe is arranged within the sump; and the lubricant supply system is configured so that the inlet end is movable within the sump.

As the inlet end is able to move within the sump, the inlet end can move with the lubricant as it is moved within the sump. Less lubricant can therefore be used, whilst keeping the inlet end immersed within the lubricant. Pumping of lubricant through the system remains uninterrupted despite a reduction in the amount of lubricant.

In exemplary embodiments, said vehicle defines a longitudinal axis, and the inlet end is configured for movement parallel to, or at least substantially parallel to, said longitudinal axis.

The longitudinal axis of the vehicle is that along which lubricant will, in the main, be displaced, due to braking or acceleration of the vehicle, or the vehicle climbing or descending a slope. The inlet end being configured for movement parallel to that axis will aid movement of the inlet end with the lubricant.

In exemplary embodiments, the gearbox further comprises a guide configured for guiding movement of the inlet end.

The guide directs movement of the inlet end in a particular direction, and so improves ease of movement of the inlet end with the lubricant.

In exemplary embodiments, the guide comprises a rail or rails, and the inlet end is coupled for movement along said rail or rails.

The rail or rails effectively direct movement of the inlet end.

In exemplary embodiments, the rail or rails comprise a first location and a second location, wherein the inlet end is coupled for movement between the first and second locations, and wherein the second location is higher than the first location.

The second location being higher than the first location encourages movement of the inlet end from the second location to the first location.

In exemplary embodiments, the rail or rails further comprise a third location, wherein the first location is between the second and third locations, wherein the inlet end is coupled for movement between the first and third locations, and wherein the third location is higher than the first location.

The third location being higher than the first location encourages movement of the inlet end from the third location to the first location, i.e. return of the inlet end to the middle first portion of the rail or rails is encouraged. In particular, the height difference between the second or third locations and the first location eases movement of the inlet end when movement of the lubricant changes direction between forwards and rearwards, e.g. when the vehicle undergoes a change of incline, such as at the crest of the hill, or when the vehicle is braked after a period of acceleration.

In exemplary embodiments, the rail or rails comprise an inclined or curved portion between the second location and the first location, and/or between the third location and the first location.

The curved or inclined portion of the rail or rails aids movement of the inlet end between the first, second and third locations.

In exemplary embodiments, the lubricant supply system comprises a body, wherein the inlet end is connected to the body and is in fluid communication with the body, and wherein the body is movably mounted on the guide.

Advantageously, mounting of the body to which the inlet end of the pipe is secured to the guide provides a simple and effective way of allowing the inlet end of the pipe to move with the lubricant.

In exemplary embodiments, the body comprises at least one roller configured for rolling contact with the guide.

The roller or rollers of the inlet body enable the inlet to be moved easily by the lubricant along the guide.

In exemplary embodiments, the body comprises a fin configured to aid movement of the body with lubricant.

In exemplary embodiments, the fin extends perpendicular to or at least substantially perpendicular to a longitudinal axis defined by said vehicle.

Such a fin increases the surface area exposed to the lubricant in the main direction of movement of the lubricant, and so increases the ease by which the body is moved by the lubricant along the longitudinal axis of the vehicle.

In exemplary embodiments, the body comprises a filter configured to filter lubricant as it enters the pipe.

Advantageously, the filter is used to aid movement of the inlet end, avoiding the need for an additional component and so decreasing cost.

In exemplary embodiments, the inlet end of the pipe is pivotably secured to the body.

Pivotable attachment of the pipe to the body allows the body to move in relation to a fixed point where the pipe leaves the interior of the sump.

In exemplary embodiments, the pipe is flexible.

The flexibility of the pipe also allows movement of the inlet end in relation to the fixed point where the pipe leaves the interior of the sump.

In exemplary embodiments, the pipe comprises an outlet end pivotably secured to a wall of the sump.

Pivotable attachment of the pipe to the sump wall also allows the inlet end to move in relation to the fixed point where the pipe leaves the interior of the sump. This is of particular use where a rigid pipe is used.

There is further provided a lubricant filter for a lubricant supply system for a vehicle. The lubricant filter is mounted within a lubricant sump, and the lubricant filter is movable within said lubricant sump.

The lubricant filter being movably mounted allows it to move with lubricant contained within the sump, allowing a reduction in the amount of lubricant contained within the sump.

In exemplary embodiments, said vehicle defines a longitudinal axis, and the lubricant filter is configured for movement parallel to, or at least substantially parallel to, said longitudinal axis.

The longitudinal axis of the vehicle is that along which lubricant will, in the main, be displaced, due to braking or acceleration of the vehicle, or the vehicle climbing or descending a slope. The filter being configured for movement parallel to that axis will aid movement of the inlet end with the lubricant.

In exemplary embodiments, the lubricant filter is configured for movable coupling with a guide configured for guiding movement of the lubricant filter.

The guide directs movement of the filter in a particular direction, and so improves ease of movement of the filter with the lubricant.

In exemplary embodiments, the filter further comprises at least one roller configured for rolling contact with the guide.

In exemplary embodiments, the body comprises a fin configured to aid movement of the filter with lubricant.

Such a fin increases the surface area exposed to the lubricant in the main direction of movement of the lubricant, and so increases the ease by which the filter is moved by the lubricant along the longitudinal axis of the vehicle.

There is also provided a lubricant supply system for a vehicle, the lubricant supply system comprising a lubricant sump configured to contain lubricant; and a pipe for transferring lubricant from the sump. The pipe comprises an inlet end for receiving lubricant from the sump, the inlet end of the pipe is arranged within the sump; and the lubricant supply system is configured so that the inlet end is movable within the sump.

In exemplary embodiments, the lubricant supply system further comprises a guide configured for guiding movement of the inlet end.

The rail or rails effectively direct movement of the inlet end.

In exemplary embodiments, the pipe is flexible.

BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1 is a schematic view of a gearbox with a lubricant supply system according to an embodiment; Figure 2 is a cross-sectional view through a sump of the lubricant supply system of Figure 1; Figures 3a, 3b and 3c are cross-sectional views through the sump of Figure 2, showing the sump of Figure 2 in different orientations; Figure 4 is an isometric view of an inlet and a guide of the lubricant supply system; Figures 5a and 5b are isometric views of the inlet and guide of Figure 4 with the inlet in different positions; Figure 6 is an isometric view of the inlet of Figure 4; Figure 7 is a cross-sectional view through the inlet and guide of Figure 2, along the line A:A; and Figure 8 is a view of the underside of the inlet of Figures 4 to 7.

DETAILED DESCRIPTION OF EMBODIMENT(S)

Figure 1 shows a gearbox in schematic form, indicated generally at 10. In this embodiment, the gearbox 10 is intended for use in a heavy vehicle, e.g. a truck. In alternative embodiments, the gearbox is suitable for use in a light vehicle such as a motorcycle.

The gearbox 10 has a lubricant supply system, indicated generally at 12. The lubricant supply system 12 is of the injection type, and is configured to deliver lubricant to the gearbox transmission (not shown). The lubricant supply system 12 has a lubricant sump 14 containing lubricant for the lubricant supply system 12. Lubricant is cycled through the system, and returned to the sump 14 under gravity once it has been used to lubricate the transmission.

With reference now to Figure 2, a pipe 20 extends within the sump 14, and transfers lubricant from the sump 14. The pipe 20 has an inlet end, indicated generally at 22, for receiving lubricant from the sump 14. The inlet end 22 is arranged within the sump 14.

The inlet end 22 is movable within the sump 14. The inlet end 22 is moved due to movement of the vehicle, and moves with lubricant 24 contained within the sump 14 as the lubricant 24 is moved within the sump 14. In use, when the gearbox 10 is fitted to a vehicle (not shown), lubricant is moved within the sump 14 due to the motion of the vehicle, and the inlet end 22 moves with the lubricant 24.

The inlet end 22 is movable in the direction of movement of the vehicle. That is, the vehicle has a longitudinal axis B (see Figure 1), and the inlet end 22 is movable along axis B in both directions, i.e. forwards and rearwards with respect to the direction of movement of the vehicle. Advantageously, this enables the inlet end 22 to easily move with the lubricant 24, as this is the direction in which the lubricant 24 will, on the whole, be moved.

Although the lubricant 24 will be moved within the sump 14 in multiple directions, e.g. as the vehicle goes around a corner, movement of the lubricant 24 within the sump 14 will in general be in line with the longitudinal axis B. The lubricant supply system 12 includes a body 32 movably mounted within the sump 14. The inlet end 22 is connected to the body 32. The inlet end 22 is in fluid communication with the body 32, so that lubricant can be transferred from the sump 14 via the body 32 and the inlet end 22.

Figures 3a, 3b and 3c show the sump 14 and the body 32 as the vehicle is driven along surfaces of different incline. Figure 3a shows the sump 14 as the vehicle is travelling along a substantially flat surface. The lubricant 24 is substantially level, i.e. evenly distributed throughout the sump 14, and the body 32 is in a middle portion 14c of the sump 14.

Figure 3b shows the sump 14 as the vehicle travels forward in the direction indicated by arrow A down an incline. The lubricant 24 moves to a front end 14a of the sump 14. As the body 32 is movable within the sump 14, the body 32 moves with the lubricant 24 towards the front end 14a of the sump 14, and the inlet end 22 moves with the body 32.

Figure 3c shows the sump 14 as the vehicle is driven forwards up an incline, so that the lubricant 24 is moved to a rear end 14b of the sump 14, the body 32 is moved towards the rear end 14b with the lubricant 24, and the inlet end 22 moves with the body 32.

Similarly, when the vehicle is driven along a relatively flat surface, if the vehicle is accelerated in a forward direction, the body 32 is moved with the lubricant 24 rearwardly in the sump 14, towards the rear end 14b. If the vehicle is braked, the body 32 is moved with the lubricant 24 in a forward direction in the sump 14, towards the forward end 14a.

As shown in Figures 3a, 3b and 3c, movement of the body 32 and so the connected inlet end 22 with the lubricant 24 ensures that the inlet end 22 remains submersed beneath the surface of the lubricant 24 as the vehicle moves. The level of lubricant 24 within the sump 14 can thus be lower than in a gearbox with a fixed inlet end, as in the prior art.

In order to guide movement of the inlet end 22 in line with the longitudinal axis B, the lubricant supply system 12 includes a guide 26, as shown in Figures 4, 5a and 5b. The guide 26 is orientated along the axis B, as shown in Figure 4. The inlet end 22 moves with the lubricant 24 along the guide 26, i.e. in line with the longitudinal axis B of the vehicle.

In this embodiment, the guide 26 is in the form of a pair of parallel rails 28 extending between the front 14a and rear 14b ends of the sump 14. The inlet end 22 is coupled for movement along the rails 28 when encouraged to do so due to movement of the vehicle and corresponding movement of the lubricant 24 in a particular direction. As shown in Figure 4, the rails 28 extend parallel to the longitudinal axis B of the vehicle, so aiding movement of the inlet end 22 in that direction within the sump 24. In alternative embodiments, the guide has a single rail, or three or more rails.

Figures 6 and 7 show the body 32 and the inlet end 22 in further detail. In this embodiment, the inlet end 22 is secured to the body 32 at a swivel joint 34 pivotable about a longitudinal axis C, as shown in Figure 6. The swivel joint 34 allows the inlet end 22 to move freely within the sump 14, without being restricted by the pipe 20. The pipe 20 is in this embodiment flexible, so as to aid movement of the inlet end 22. In an alternative embodiment, the inlet end is secured to the inlet body at a fixed joint.

The pipe 20 is secured to a wall 17 of the sump 14, and is there connected to a further pipe 18 for the transfer of lubricant to the lubricant supply system. In an alternative embodiment, the pipe is rigid, rather than flexible, and the pipe is secured to the sump wall at a swivel joint, such that movement of the inlet end within the sump is enabled.

In this embodiment, the body 32 is movably mounted to the rails 28. The body 32 has rollers 36, as shown in Figures 6 and 7, configured for contact with the rails 28, to assist movement of the body 32 along the rails 28. In this embodiment, the rollers 36 are roller bearings. In alternative embodiments, some other type of roller is used, or the body has some other suitable form of contact with the railings 28.

As shown in Figure 7, the rails 28 of this embodiment comprise a lip 38 by which the rollers 36 are constrained to the rails 28. The rails 28 of this embodiment are substantially 3-shaped in cross-section, such that the lip 38 extends substantially perpendicular to a floor 15 of the sump 14, and so constrains the rollers 36 with respect to the rails 28. Each rail 28 has an upper lip 40 extending at an angle from a body 29 of the rail, serving to guide the rollers 36 and retain them on the rail.

In this embodiment, the guide 26 also aids the return of the inlet end 22 to a middle portion of the sump 14 with movement of the lubricant 24. The rails 28 each have a first location in the form of a middle portion 28a, situated between a second location 28b and a third location 28c. The second and third locations 28b, 28c are end portions 28b, 28c of the rails 28, as shown in Figure 5a. Each end portion 28b, 28c of the rails is higher than the middle portion 28a in relation to the floor 15 of the sump 14. The relative height of the end portions 28b, 28c assist the return of the body 32, and so the connected inlet end 22, to the middle portion 28a as the lubricant 24 returns to a level position, as shown in Figure 3a.

The force applied by the lubricant 24 to move the inlet end 22 is commonly stronger when the inlet end 22 is moved to either end portion 28b, 28c of the rails 28, due to acceleration or braking forces, or the vehicle climbing or descending an incline. This means that the inlet end 22 is more easily moved with the lubricant 24 to the end portions 28b, 28c than it is returned to the middle portion 28a. The higher end portions 28b, 28c advantageously assist the inlet end 22 in returning to the middle portion 28a.

In this embodiment, the end portions 28b, 28c are inclined with respect to the middle portion 28a by 5°, so as to reach a point higher than the middle portion 28a. In alternative embodiments, the end portions of the rails are inclined by between 4° and 7°, or between 1 and 15° from the horizontal, i.e. with respect to the middle portion 28a. In alternative embodiments, the end portions are curved so as to reach a point higher than the middle portion. In alternative embodiments, the rails are substantially flat.

The body 32 has a fin 42 to aid movement of the body 32 with the lubricant 24. The fin 42 serves to increase the surface area of the body 32 exposed to the direction of movement of the lubricant 24. In alternative embodiments, the body has more than one fin.

The fin 42 extends perpendicular to the direction of movement of the body 32, i.e. perpendicular to the longitudinal axis B, and so is acted upon in the main direction of the lubricant 24. Ease of movement of the body 32 and the connected inlet end 22 by the lubricant 24 is thus improved.

The body 32 includes a filter 44 for filtration of lubricant as it leaves the sump 14, as shown in Figure 8. In this embodiment, the filter 44 is secured to an underside 33 of the inlet body 32, such that lubricant entering the pipe 20 must pass through the filter 44. Advantageously, the filter 44 moves with the body 32, so that all lubricant 24 is filtered as it passes into the pipe 20.

The mass of the body 32 can be adjusted to optimise movement of the body 32 with the lubricant 24. Adjustment of the mass of the body 32 is achieved by adjusting the material used for the body 32, or, in this embodiment adding an additional ballast weight 46 to the body 32. The ballast weight 46 is secured to the body 32, thus adjusting the mass of the inlet end 22.

Claims

CLAIMS1. A gearbox for a vehicle, the gearbox comprising a lubricant supply system, wherein the lubricant supply system comprises: a lubricant sump configured to contain lubricant; and a pipe for transferring lubricant from the sump; wherein the pipe comprises an inlet end for receiving lubricant from the sump, wherein the inlet end of the pipe is arranged within the sump; and wherein the lubricant supply system is configured so that the inlet end is movable within the sump.
2. The gearbox according to claim 1, wherein said vehicle defines a longitudinal axis, and wherein the inlet end is configured for movement parallel to, or at least substantially parallel to, said longitudinal axis.
3. The gearbox according to claim 1 or claim 2, further comprising a guide configured for guiding movement of the inlet end.
4. The gearbox according to claim 3, wherein the guide comprises a rail or rails, and wherein the inlet end is coupled for movement along said rail or rails.
5. The gearbox according to claim 4, wherein the rail or rails comprise a first location and a second location, wherein the inlet end is coupled for movement between the first and second locations, and wherein the second location is higher than the first location.
6. The gearbox according to claim 5, wherein the rail or rails further comprise a third location, wherein the first location is between the second and third locations, wherein the inlet end is coupled for movement between the first and third locations, and wherein the third location is higher than the first location.
7. The gearbox according to claim 6 wherein the rail or rails comprise an inclined or curved portion between the second location and the first location, and/or between the third location and the first location.
8. The gearbox according to any one of claims 3 to 7, wherein the lubricant supply system comprises a body, wherein the inlet end is connected to the body and is in fluid communication with the body, and wherein the body is movably mounted on the guide.
9. The gearbox according to claim 8, wherein the body comprises at least one roller configured for rolling contact with the guide.
10. The gearbox according to claim 8 or claim 9, wherein the body comprises a fin configured to aid movement of the body with lubricant.
11. The gearbox according to claim 10, wherein the fin extends perpendicular to or at least substantially perpendicular to a longitudinal axis defined by said vehicle.
12. The gearbox according to any one of claims 8 to 11, wherein the body comprises a filter configured to filter lubricant as it enters the pipe.
13. The gearbox according to any one of claims 8 to 12, wherein the inlet end of the pipe is pivotably secured to the body.
14. The gearbox according to any one of claims 1 to 13, wherein the pipe is flexible.
15. The gearbox according to any one of claims 1 to 14, wherein the pipe comprises an outlet end pivotably secured to a wall of the sump.
16. A lubricant filter for a lubricant supply system for a vehicle; wherein the lubricant filter is mounted within a lubricant sump; and wherein the lubricant filter is movable within said lubricant sump.
17. The lubricant filter according to claim 16, wherein said vehicle defines a longitudinal axis, and wherein the lubricant filter is configured for movement parallel to, or at least substantially parallel to, said longitudinal axis.
18. The lubricant filter according to claim 16 or claim 17, wherein the lubricant filter is configured for movable coupling with a guide configured for guiding movement of the lubricant filter.
19. The lubricant filter according to claim 18, further comprising at least one roller configured for rolling contact with the guide.
20. The lubricant filter according to any one of claims 16 to 19, further comprising a fin configured to aid movement of the filter with lubricant.
21. The lubricant filter according to claim 20, wherein the fin extends perpendicular to or at least substantially perpendicular to a longitudinal axis defined by said vehicle.