WO2009134150A1

WO2009134150A1 - Continual fluid supply for gear boxes

Info

Publication number: WO2009134150A1
Application number: PCT/NZ2009/000063
Authority: WO
Inventors: Ernest Paul Goatley
Original assignee: Goatley Technologies Limited
Priority date: 2008-05-02
Filing date: 2009-04-30
Publication date: 2009-11-05
Also published as: NZ567877A

Abstract

A gearbox which includes:- a hub having: - a stationary housing; and - a rotating interior portion including at least one piston assembly and at least one clutch pack; and at least one gear; wherein the hub, in use, is connected to a fluid supply, the gearbox characterised in that the rotating interior portion and stationary housing of the hub are respectively configured, such that during operation of the piston when the clutch pack is engaging or engaged with the gear, a continual supply of fluid, is provided to the piston.

Description

CONTINUAL FLUID SUPPLY FOR GEAR BOXES

STATEMENT OF CORRESPONDING APPLICATIONS

This application is based on the Complete Specification filed in relation to New Zealand Patent Application Number 567877, the entire contents of which are incorporated herein by reference.

TECHNICAL FIELD

The present invention relates to improvements in and relating to gearboxes.

BACKGROUND ART

Existing gearboxes/transmissions suffer from a number of problems. There are limitations particularly having regard to compatibility with new automotive propulsion technology.

For ease of reference only the present invention will now be discussed in relation automotive gearboxes/transmissions. However, this should not be seen as limiting the scope of the present invention.

Automatic transmissions suffer from being expensive, heavy and very fuel inefficient. They can also be slow to select an appropriate lower gear, for example, when a driver is seeking to accelerate rapidly to overtake another vehicle.

Manual transmissions whilst lighter more fuel efficient and less expensive to build and maintain but can be difficult to operate. They can also be tiresome to operate in congested traffic or in stop start traffic situations such as are found in busy cities. Manual sequential gearboxes whilst regarded by many as easier to operate than a manual gear box but are more expensive. Furthermore, sequential gear boxes require the gears to be engaged in a sequential order which can make for slower selection of a gear if it is not the next gear in the sequence.

One gearbox which the inventor of the present invention devised which attempted to overcome these difficulties is described in WO 00/06927 to Goatley. However, the inventor has subsequently found that to improve the operation and robustness of this gearbox it needs to be configured in a particular manner.

All references, including any patents or patent applications cited in this specification are hereby incorporated by reference. No admission is made that any reference constitutes prior art. The discussion of the references states what their authors assert, and the applicants reserve the right to challenge the accuracy and pertinency of the cited documents. It will be clearly understood that, although a number of prior art publications are referred to herein, this reference does not constitute an admission that any of these documents form part of the common general knowledge in the art, in New Zealand or in any other country.

It is acknowledged that the term 'comprise' may, under varying jurisdictions, be attributed with either an exclusive or an inclusive meaning. For the purpose of this specification, and unless otherwise noted, the term 'comprise' shall have an inclusive meaning - i.e. that it will be taken to mean an inclusion of not only the listed components it directly references, but also other non-specified components or elements. This rationale will also be used when the term 'comprised' or 'comprising' is used in relation to one or more steps in a method or process.

It is an object of the present invention to address the foregoing problems or at least to provide the public with a useful choice.

Further aspects and advantages of the present invention will become apparent from the ensuing description which is given by way of example only.

DISCLOSURE OF INVENTION

A gearbox which includes:

• a hub having:

- a stationary housing; and

- a rotating interior portion including at least one piston assembly and at least one clutch pack; and

• at least one gear;

wherein the hub, in use, is connected to a fluid supply, the gearbox characterised in that the rotating interior portion and stationary housing of the hub are respectively configured, such that during operation of the piston when the clutch pack is engaging or engaged with the gear, a continual supply of fluid, is provided to the piston.

Preferably, the configuration of the interior portion and stationary housing is such as to also allow, a controlled amount of fluid to be released from, the piston assembly, during the operation of the piston. This is preferably achieved via a bypass arrangement.

A method of operating a manual gearbox including the step of:

- continually supplying fluid to at least one piston in the gearbox whilst the piston is engaging a clutch pack to a gear.

Preferably, the amount of fluid supplied to the piston has to:

• be greater than the fluid which is released from the piston assembly whilst the piston is engaged; and

• provide sufficient pressure to activate the piston as well as adequate force to clamp the clutch plates to engage a gear.

The hub may have a variety of configurations without departing from the scope of the present invention.

The stationary housing may be dimensioned to provide a space in which the interior rotating portion of the hub can freely rotate.

In preferred embodiments the interior portion of the hub may be attached to a gear shaft to rotate therewith.

In other embodiments the interior portion of the hub may be attached to a drive shaft. For example, when the gear box is being used to operate a primary clutch.

For ease of reference the interior portion of the hub will now simply be described as being attached to a shaft.

In preferred embodiments the interior portion of the hub may have a region splined or by some method mated or otherwise attached to the shaft.

In some embodiments, particularly, but not necessarily exclusively, simple single gear transmissions, the hub may be integrally formed with the shaft.

The stationary housing of the hub may be configured to have one or more apertures or passages which, in use, can provide fluid to the rotating interior portion of the hub.

The rotating interior portion may have one or more apertures/passages to direct fluid to the piston assembly or piston assemblies.

The respective apertures/passages of the rotating interior portion and stationary housing may be operatively aligned with one another along the longitudinal axis of the shaft to provide a fluid connection.

The piston assembly can have a multitude of different configurations.

In general the piston assembly may include a chamber and piston.

In preferred embodiments the piston assembly may include a piston and chamber located in, or formed within, the rotating interior portion of the hub. Most preferably, the piston may be annular and the chamber may be formed by an annular groove in the rotating interior portion of the hub.

The clutch packs may come in a number of different forms without departing from the scope of the present invention.

In preferred embodiments the clutch packs may be in the form of a wet clutch having a number of friction discs or plates or such like.

Most preferably the clutch pack may include:

• a first series of driven clutch plates which are attached to the rotating interior portion of the hub for rotation therewith;

• a second series of drive clutch plates which are attached to the gear;

wherein the driven and drive clutch plates are arranged as alternate layers.

In some embodiments the clutch packs may be in the form of a dry clutch.

In preferred embodiments the friction plates may be annular.

In some embodiments the clutch packs may be formed as cones or in some other configurations known and used in the art to provide drive between two or more gears. Most preferably annular friction plates and the annular pistons may be concentrically arranged with respect to the shaft.

The gear may be any toothed wheel which in use can alter relative the speed of the engine and the speed and/or torque of the device or part(s) driven by the engine.

In preferred embodiments the gear may have a collar.

The fluid supply can be provided from a number of different sources.

In some embodiments the fluid supply may be located remote from the gear box.

In preferred embodiments the fluid supply may be sourced from the gear box.

The fluid may be any fluid capable of operating a piston.

The fluid may be liquid or gas.

In some embodiments the fluid may be hydraulic fluid.

In preferred embodiments the fluid may be gear box (i.e. transmission) oil sourced from the gear box itself.

The fluid supply may include a pump to provide the fluid to the piston assembly.

The pump can be almost any type of pump. The size and capacity of the pump are determined by the clutch packs and the requirements of the gearbox to operate. In general pump size and capacity is determined by the degree of clutch plate slippage. The more clutch slippage that occurs the greater the heat produced and thus the greater the controlled amount of oil that has to be released to lubricate and cool the rotating interior portion.

In some embodiments the fluid may be a pressurised gas.

The connection of the fluid supply to the piston assembly may also include one or more valves to control the flow of fluid to the piston.

In preferred embodiments the valves may be solenoid on/off valves.

The valves may be operated by a suitable controlling system.

In general the controlling system may include a suitably programmed CPU or such like.

The CPU may receive input from one or more sensors and/or from a user interface.

In preferred embodiments the rotating interior portion and stationary housing of the hub may be situated in between at least one, but preferably at least two bushes to facilitate spinning of the rotating interior portion.

In preferred embodiments the bush(es) provide a degree of tolerance between the rotating interior portion and stationary housing of the hub to allow for fluid to pass in between.

In some preferred embodiments the bush may include one or more apertures/passages which allow for the transfer of fluid to the interior rotating portion of the hub.

In preferred embodiments rotating interior portion and stationary housing of the hub may also include one or more sealing rings.

The rotating interior portion and stationary housing of the hub may be configured to continually supply fluid to the piston during operation in a number of different ways.

In preferred embodiments apertures/passages may direct fluid to the piston and may also be at least partially open to the outer surface of the rotating interior portion of the hub. Thus, when fluid under pressure is being supplied to the piston an amount of fluid is also bypassed around the spinning hub.

The tolerances between the respective contacting surfaces of the:

• bushes and/or sealing rings; and

• the rotating interior portion and stationary housing;

is such as to allow a controlled amount of fluid to exit the hub and return to the fluid supply.

In general such embodiments may be utilised when the fluid supply is the transmission oil.

In some alternate embodiments the wall of the chamber formed by the rotating interior portion of the hub may include one or more apertures/passages which can direct a controlled amount of fluid out of the chamber to the outer surface of the rotating interior portion of the hub. The tolerances between the respective contacting surfaces of the:

• bushes and/or sealing rings; and

• the rotating interior portion and stationary housing;

According to a further aspect of the present invention there is provided an engine or motor which includes a gearbox.

According to yet another aspect of the present invention there is provided a vehicle which includes a gearbox. According to another aspect of the present invention there is provided a machine which includes a gearbox.

According to another aspect of the present invention there is provided a hub having:

- a stationary housing; and

wherein the hub, in use, is connected to a fluid supply, and the rotating interior portion and stationary housing of the hub are respectively configured, such that during operation of a piston when the clutch pack is engaging or engaged with a gear, a continual supply of fluid, is provided to the piston.

According to another aspect of the present invention there is provided a gear box substantially as described above which has two hubs which are positioned on either side of a gear.

Preferably, the gear may be first gear, or reverse gear, or any other heavily loaded gear.

In these two hub embodiments the gear may be symmetrical when viewed side on. This configuration of gear allows for clutch plates to be attached to the gear on either side.

In particular, each face of the gear may have an integral collar to which clutch plates can attach.

Preferably, the hubs are configured to operate simultaneously providing clamping pressure to both sides of the selected gear A machine, motor, vehicle which includes a gear box in accordance with the present invention substantially as described above.

The term 'controlled amount of fluid' as used herein refers to an amount of fluid which although released from the piston assembly is not of a sufficient quantity to reduce the pressure of the fluid so as to compromise the clamping force of the piston. In other words the amount of oil supplied to the piston has to be significantly greater than the amount of released from the piston assembly.

Thus, preferred embodiments of the present invention can have a number of advantages over the prior art which can include:

The continual purging of fluid from the hub during operation of the piston allows for the cooling of the fluid;

The continual purging of fluid from the hub during operation of the piston also assists with cooling the hub;

The continual purging of fluid from the hub during operation of the piston also assists with lubricating the spinning interior portion of the hub;

Providing a transmission which is robust;

Providing a transmission which is relatively light weight;

Providing a transmission which is relatively inexpensive to construct and maintain;

Providing a transmission which is capable of quickly changing gears and which can allow for selection of gears out of sequence.

Providing a gear box which can be set up so that the gears are either:

• automatically selected; or • manually selected by a user.

BRIEF DESCRIPTION OF DRAWINGS

Further aspects of the present invention will become apparent from the following description which is given by way of example only and with reference to the accompanying drawings in which:

Figure 1 is a cross sectional schematic view through a part of a gearbox in accordance with one preferred embodiment of the present invention.

Figure 2 is an enlarged view of a section of Figure 1 illustrating a bypass passage for the controlled release of oil from the piston assembly.

BEST MODES FOR CARRYING OUT THE INVENTION

With respect to the drawings there is shown a portion of a gear box (1). The gear box (1) has a gear box shaft (2) about which there is a first gear (3) and a second gear (4). The gears (3) and (4) rest on respective needle roller bearings (5,6). The gears each have an integral collar (100,101).

Positioned in between the gears (3,4) is a hub generally indicated by arrow (7).

The hub (7) has a stationary housing (8) and a rotating interior portion (9) which is splined (not shown) to the shaft (2). Situated in between the stationary housing (8) and a rotating interior portion (9) is an annular bush (10). The stationary housing (8) has apertures (11 ,12) which allow for fluid from respective lines (13,14) to pass through the housing (8). The apertures (11 ,12) are aligned with circumferential passages (130,140) in the bush (10). The passages (130,140) in the bush (10) connect with a circumferential passages (15,16) in the rotating interior portion (9). The passages (15,16) feed fluid to piston chambers (17,18), formed in the rotating interior portion (9), via outlets (21 , 22) so as to operate pistons (19,20). The pistons (19,20) have inner and outer annular sealing rings (23,24 and 25,26) thereon.

Situated in between the gears (3,4) and pistons (19,20) are clutch packs having a first series of driven annular clutch plates (27) which are attached via dogs (not shown) to the rotating interior portion (9) of the hub. Along with a second series of drive annular clutch plates (28) which are attached via splines to the gears (3,4).

The gears (3,4) are held on position on the shaft (2) by respective thrust load bearings (2000) and (2001).

The outer surface of the rotating interior portion (9) has annular ring seals (29) thereon.

The fluid supply (not shown) is the transmission oil of the gear box and this is drawn into the lines (13,14) via a pump (not shown). The lines (13,14) have respective solenoid valves (30,31) which control the supply of oil to the pistons (19,20). To operate a desired piston the associated valve is moved to an open position to allow the pump to supply oil to the piston as is shown in relation to piston (19). As can be seen the oil (shown in black) flows along line (13) in the direction of arrow (1000), passes through valve (30), and passages (11 and 130) then out of outlets (21) to move piston (19), in the direction of arrow (1001). This causes the piston to push the respective clutch plates (27) and (28) together so as to frictionally couple to one another to engage gear (3).

The pump also acts to force the oil along a bypass passage (as shown by the arrows in Figure 2) formed in between the outer surface of the rotating interior portion (9) and bush (10) back out into the transmission housing (not shown) to rejoin the transmission oil in the sump of the transmission (not shown).

The valve (30) is moved to a closed position when a gear is no longer required to be engaged. As no pressure is being applied to the piston via the action of the pump the clutch discs separate and this allows the piston to retreat.

The pump and valves (30,31) are operated by any suitable controlling system (not shown). The controlling system may automatically engage and disengage gears, or may alternately have a user interface to allow the user to select gears.

Aspects of the present invention have been described by way of example only and it should be appreciated that modifications and additions may be made thereto without departing from the scope of the appended claims.

Claims

WHAT WE CLAIM IS:

1. A gearbox which includes:

-a hub having:

- a stationary housing; and

-at least one gear;

2. A gearbox as claimed in claim 1 wherein the configuration of the interior portion and stationary housing allows a controlled amount of fluid to be released from, the piston assembly, during the operation of the piston.

3. A gearbox as claimed in claim 1 or claim 2 wherein the piston assembly may include a piston and chamber located in, or formed within, the rotating interior portion of the hub.

4. A gearbox as claimed in claim 3 wherein the piston may be annular and the chamber is formed by an annular groove in the rotating interior portion of the hub.

5. A gearbox as claimed in any one of the preceding claims wherein the clutch pack includes: • a first series of driven clutch plates which are attached to the rotating interior portion of the hub for rotation therewith;

• a second series of drive clutch plates which are attached to the gear;

wherein the driven and drive clutch plates are arranged as alternate layers.

6. A gearbox as claimed in claim 4 wherein annular friction plates and the annular pistons are concentrically arranged with respect to the shaft.

7. A gearbox as claimed in any one of the preceding claims wherein the fluid supply is located remote from the gear box.

8. A gearbox as claimed in any one of claims 1-6 wherein the fluid supply is sourced from the gear box.

9. A gearbox as claimed in any one of claims 1-7 wherein the fluid is liquid or gas.

10. A gearbox as claimed in any one of claims 1-7 wherein the fluid is hydraulic fluid.

11. A gearbox as claimed in claim 8 wherein the fluid supply is gear box (i.e. transmission) oil.

12. A gearbox as described in claim 1 wherein the fluid supply includes a pump to provide the fluid to the piston assembly.

13. A gearbox as claimed in claim 1 wherein the fluid is a pressurised gas.

14. A gearbox as claimed in claim 1 wherein the connection of the fluid supply to the piston assembly includes one or more valves to control the flow of fluid to the piston.

15. A gearbox as claimed in claim 14 wherein the valves are solenoid on/off valves.

16. A gearbox as claimed in claim 14 or claim 15 wherein the valves are operated by a suitable controlling system.

17. A gearbox as claimed in claim 16 wherein the controlling system includes a suitably programmed CPU or such like.

18. A gearbox as claimed in claim 16 wherein the CPU receives input from one or more sensors and/or from a user interface.

19. A gearbox as claimed in claim 1 or claim 2 wherein the rotating interior portion and stationary housing of the hub is situated in between at least one, but preferably two, bushes to facilitate spinning of the rotating interior.

20. A gearbox as claimed in claim 19 when dependent on claim 2 wherein the bush(es) provide a degree of tolerance between the rotating interior portion and stationary housing of the hub to allow for fluid to pass in between.

21. A gearbox as claimed in claim 19 or 20 wherein the bush includes one or more apertures/passages which allow for the transfer of fluid to the interior rotating portion of the hub.

22. A gearbox as claimed in claim 1 or claim 2 wherein situated in between the rotating interior portion and stationary housing of the hub are one or more sealing rings.

23. A gearbox as claimed in claim 21 wherein the apertures/passages direct fluid to the piston and are also at least partially open to the outer surface of the rotating interior portion of the hub.

24. A gearbox as claimed in claim 1 or claim 2 wherein tolerances between respective contacting surfaces of:

• bushes and/or sealing rings; and

• the rotating interior portion and stationary housing;

are such as to allow a controlled amount of fluid to exit the hub and return to the fluid supply.

25. A gearbox as claimed in claim 1 or claim 2 wherein a wall of the chamber formed by the rotating interior portion of the hub includes one or more apertures/passages which can direct a controlled amount of fluid out of the chamber to the outer surface of the rotating interior portion of the hub.

26. A method of operating a manual gearbox including the step of:

continually supplying fluid to at least one piston in the gearbox whilst the piston is engaging a clutch pack to a gear.

27. A method as claimed in claim 26 wherein the amount of fluid supplied to the piston has to be greater than the fluid which is released from the piston assembly whilst the piston is engaged.

28. An engine or motor which includes a gearbox as claimed in any one of claims 1-25.

29. A vehicle which includes a gearbox as claimed in any one of claims 1-25.

30. A machine which includes a gearbox as claimed in any one of claims 1-25.

31. A hub having:

a stationary housing; and

a rotating interior portion including at least one piston assembly and at least one clutch pack; and

32. A gear box which has two hubs as claimed in claim 31 which are positioned on either side of a gear.

33. A gear box as claimed in claim 32 wherein the gear is first gear, or reverse gear, or any other heavily loaded gear.

34. A vehicle which includes a gear box as claimed in claim 32.