WO2014116175A1

WO2014116175A1 - Gearbox with manoeuvring fork and vehicle including such a gearbox

Info

Publication number: WO2014116175A1
Application number: PCT/SE2014/050093
Authority: WO
Inventors: Dieter Slapak
Original assignee: Scania Cv Ab
Priority date: 2013-01-28
Filing date: 2014-01-27
Publication date: 2014-07-31
Also published as: DE112014000320T5; BR112015013623A2; SE1350082A1

Abstract

A gearbox (6) comprises a main shaft (10) on which at least one first and one second cogwheel (12, 14) with different diameters are rotatably journalled, an axially shiftable first manoeuvring sleeve (32) which is rotatably connected with the main shaft (10) and which is designed to engage with the first and the second cogwheels (12, 14) in order to optionally bring the cogwheels (12, 14) in engagement with the main shaft (10) and a first manoeuvring fork (38) which is designed to axially engage with the first manoeuvring sleeve (32) and which is designed to shift the first manoeuvring sleeve (32) axially. The first manoeuvring fork (38) expands at least partly axially along a first or a second section (42, 40) of the main shaft (10), the second section (42, 40) on which the first or the second cogwheel (12, 14) is arranged. The invention also pertains to a vehicle (1) comprising such a gearbox (6).

Description

GEARBOX WITH MANOEUVRING FORK AND VEHICLE INCLUDING SUCH A

GEARBOX

BACKGROUND AND PRIOR ART

The invention pertains to a gearbox according to the preamble of patent claim 1 and a vehicle, which comprises such a gearbox according to the preamble of patent claim 10.

A gearbox contains a large number of interacting components, which impact the geometrical the shape and weight of the gearbox. In the event the gearbox is mounted in a vehicle, the length and weight of the gearbox will impact the length and weight of the entire vehicle. The number of components also impacts the function of the gearbox. Under certain operational conditions the preference is that it should be possible to carry out shifting between different gears in the gearbox as quickly and evenly as possible, so that the vehicle does not loose speed and so that the shifting does not adversely affect the driving comfort.

Today's gearboxes have a length which, among others, depends on the relative placement of the cogwheels in the gearbox. In manual gearboxes the cogwheels are placed in a specific relative order in order to facilitate shifting. A gearbox of split- type, which comprises a main and a side shaft, has a large number of cogwheels, depending on the area of applicability, which are arranged on both the main and the side shafts. On the main shaft, the cogwheels are rotatably journalled and connected with the main shaft with axially shif table manoeuvring sleeves depending on which gear is desired for the relevant operational state. The manoeuvring sleeves are shifted axially with manoeuvring forks, which are designed to engage axi- ally with the respective manoeuvring sleeves.

The relative placement of the cogwheels in today's gearboxes entails that the coupling sleeve must leave the cogwheel with a certain clearance before the coupling sleeve engages with the next cogwheel.

The document EP-A 1-2441980 pertains to a gearbox, which comprises a main and a side shaft on which a number of cogwheels are arranged. SUMMARY OF THE INVENTION

Despite prior art, there is a need to develop a gearbox which has a limited geometrical shape and weight, so that the vehicle, in which the gearbox is mounted, may be designed to be shorter and with a lower weight, which would entail a cost saving in the manufacture of both the gearbox and the vehicle and a saving of fuel in the operation of the vehicle. If the vehicle's fuel consumption may be reduced, there is also potential for reducing emissions from the vehicle. The objective of the present invention is thus to provide a gearbox, with a limited length expansion.

Another objective of the invention is to provide a gearbox with a low weight. Another objective of the invention is to provide a gearbox with a short shifting time between different gears.

These objectives are achieved with a gearbox of the type mentioned above, which is characterised by the features specified in patent claim 1.

By placing the cogwheels on the main shaft, so the cogwheels that interact with a joint manoeuvring sleeve have a diameter difference, the cogwheels may be placed next to each other at a small distance and still allow for the manoeuvring sleeve to be shifted axially with the manoeuvring fork. In an electronic automatic gearbox the cogwheels do not need to be placed in any specific relative order. If a cogwheel with a large diameter is placed next to a cogwheel with a small diameter, the manoeuvring fork for a manoeuvring sleeve arranged between the cogwheels may be bent, so that it reaches into the space between the cogwheels. With such a gearbox the main shaft and also the side shaft may be made compact and have a limited length, entailing that the entire gearbox may be designed as compact with a limited length. The compact design and limited length also entails that the weight of the gearbox is reduced. As a result of a shorter gearbox, the vehicle, in which the gearbox is mounted, may also be made shorter, which entails that the vehicle's total length and weight are reduced. The proposed solution with a compact and shorter gearbox. Also entails that space is provided for various components which are, among others, used to control the gearbox. By placing the cogwheels in a relative order on the main shaft, so that the first and third gears' cogwheels are connected and disconnected with a first joint manoeuvring sleeve, and the second and fourth gears' cogwheels are connected and disconnected with a second joint manoeuvring sleeve, the first manoeuvring sleeve may, when shifting from first to second gear, be disengaged from the first gear' s cogwheel at the same time as the second manoeuvring sleeve is brought into engagement with the second gear's cogwheel. Similar connection and disconnection is carried out when shifting between the other gears. The time required for gear shifting may thus be reduced when two manoeuvring sleeves interact during shifting. If only one manoeuvring sleeve is used when shifting gears, the manoeuvring sleeve must first leave the first gear's cogwheel before the manoeuvring sleeve engages with the second gear's cogwheel. With the proposed solution, the engagement with the second gear's cogwheel may occur at the same time as the first manoeuvring sleeve leaves the first gear's cogwheel. The above specified objectives are achieved also with a vehicle of the type mentioned above, which is characterised by the features specified in patent claim 10.

Other features and advantages of the invention are set out in the example descriptions below. BRIEF DESCRIPTION OF DRAWINGS

Below is a description, as an example, of a preferred embodiment of the invention with reference to the enclosed drawings, in which: Fig. 1 shows in a schematic side view of a vehicle with a gearbox according to the present invention,

Fig. 2 shows a partial view of the gearbox according to the present invention, and

Fig. 3 shows a detailed view of the gearbox according to Fig. 2. DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT OF THE INVENTION

Fig. 1 shows a vehicle 1 in a schematic side view, the vehicle 1 of which is equipped with a combustion engine 2, which drives the driving wheels 4 of the vehicle 1 via a gearbox 6 ac- cording to the present invention. The gearbox 6 is connected to the driving wheels 4 via a conventional transmission comprising, among others, a propeller shaft 8.

Fig. 2 shows a partial view of the gearbox 6 according to the present invention. The gearbox 6 comprises a main shaft 10 on which a first cogwheel 12, a second cogwheel 14, a third cog- wheel 16 and a fourth cogwheel 18 are arranged with rolling bearings 20. The gearbox 6 comprises a side shaft 22 on which cogwheel elements 24 are fixedly connected, the cogwheel elements 24 of which are in engagement with the cogwheels 12, 14, 16, 18 on the main shaft 10. The cogwheels 12, 14, 16, 18 have different diameters to be able to achieve different gearings through the gearbox 6. The main shaft 10 and the side shaft 22 are parallel with each other, and the gearbox 6, as shown in the example embodiment in Fig. 2, is of a split-type. To the left in the figure, an output shaft 26 of the combustion engine 2 is connected with the main shaft 10 of the gearbox 6 via a multi-plate clutch 30. On the second end of the main shaft 10 there is a cardan joint 28 for connection with the propeller shaft 8. An axially shiftable first manoeuvring sleeve 32 is designed to engage with the first and the second cogwheels 12, 14 in order to optionally bring the cogwheels 12, 14 into engagement with the main shaft 10. The first manoeuvring sleeve 32 is thus rotatably connected with the main shaft 10 and brought to rotate by the main shaft 10 when the main shaft 10 rotates. When the first cogwheel 12, which may e.g. constitute the first gear position, is to be con- nected, the first manoeuvring sleeve 32 is moved in an axial direction toward the first cogwheel 12 and engages with the first cogwheel 12, so that the first cogwheel 12 is rotatably locked and fixed on the main shaft 10. In order for the first manoeuvring sleeve 32 to be locked with the first cogwheel 12, the first manoeuvring sleeve 32 and the first cogwheel 12 are equipped with connecting elements 34, such as interacting splines. When the first cog- wheel 12 is connected with the main shaft 10, the combustion engine's 2 torque may be transmitted via the cogwheel elements 24 on the side shaft 22 and further to the first cogwheel 12, which transfers the torque to the main shaft 10, which in turn through the cardan joint 28 emits a torque to the propeller shaft 8 and the vehicle's 1 driving wheels. The same procedure is repeated when the second, third and fourth cogwheels 14, 16, 18 are to be connected with the main shaft 10 when an upward or downward shift is made through the gearbox 6. The third and the fourth cogwheels 16, 18 are connected with the main shaft 10 via an axially shiftable second manoeuvring sleeve 36. The first and second manoeuvring sleeves 32, 36 may also take up an intermediate position, in which the manoeuvring sleeves 32, 36 are not in engagement with any of the adjacent cogwheels 12, 14, 16, 18. Thus a neutral position has been achieved in the gearbox 6.

A first manoeuvring fork 38 is designed to axially engage with the first manoeuvring sleeve 32 and is designed to shift the first manoeuvring sleeve 32 axially along the main shaft 10. The first manoeuvring fork 38 expands at least partly axially along a second section 40 of the main shaft 10, the second section 40 on which the second cogwheel 14 is arranged. It should also be possible to design the first manoeuvring fork 38 so that it expands at least partly axially along a first section 42 of the main shaft 10, the first section 42 on which the first cogwheel 12 is arranged. According to the example embodiment displayed in Fig. 2, the second cogwheel 14 has a smaller diameter than the first cogwheel 12, which entails that the first manoeuvring fork 38 will extend axially outside the second cogwheel 14 at a radial distance from the main shaft 10, which is larger than the radial distance outside the main shaft 10 which the second cogwheel 14 extends. Further, the first manoeuvring fork 38 has a radial expansion, which exceeds the radial expansion of the first cogwheel 12, which, according to the example embodiment displayed, has a larger radius than the second cogwheel 14. Thus the first manoeuvring fork 38 will have a bent shape.

The first manoeuvring fork 38 is connected with an axially shiftable first manoeuvring element 44, which is connected with a first manoeuvring rod 46 with which the first manoeu- vring fork 38 is connected. The first manoeuvring element 44 is a pneumatic or hydraulic cylinder, but may also be an electric linear motor. The first manoeuvring element 44 must shift the first manoeuvring rod 46 axially, so that the first manoeuvring fork 38 and thus the first manoeuvring sleeve 32 are shifted axially. Thus, the first manoeuvring element 44 is activated when the first and second cogwheels 12, 14 are connected with and released from the main shaft 10 through the first manoeuvring sleeve 32.

The first manoeuvring rod 46 expands substantially in parallel with the main shaft 10 and at a radial distance from the main shaft 10 which is larger than the radial expansion of the first cogwheel 12, which, according to the example embodiment, has the largest radius. Thus, an axial shifting is facilitated of the first manoeuvring rod 46 without any conflict with the first cogwheel 12.

The third and fourth cogwheels 16, 18 may, as mentioned above, be optionally brought into engagement with the main shaft 10 through the axially shiftable second manoeuvring sleeve 36. A second manoeuvring fork 50 is designed to axially engage with the second manoeuvring sleeve 36 and is designed to shift the second manoeuvring sleeve 36 axially along the main shaft 10. The second manoeuvring fork 50 expands at least partly axially along a third section 52 of the main shaft 10, the third section 52 on which the second cogwheel 16 is arranged. It should also be possible to design the second manoeuvring fork 38 so that it expands at least partly axially along a fourth section 54 of the main shaft 10, the fourth section 54 on which the fourth cogwheel 18 is arranged. As showed in Fig. 2, the third cogwheel 16 has a larger radius than the fourth cogwheel 18. The second manoeuvring fork 50 is connected with a second manoeuvring rod 56 which is shifted axially by a second manoeuvring element 58, which may be a hydraulic or a pneumatic cylinder, or an electric linear motor.

Preferably, the respective manoeuvring forks 38, 50 interact with the respective manoeuvring sleeves 32, 36, so that the manoeuvring forks 38, 50 extend into a track 60, which is designed in the periphery of the manoeuvring sleeve 32, 36. Thus, the manoeuvring forks 38, 50 may shift the manoeuvring sleeves 32, 36 axially, at the same time as the manoeuvring sleeves 32, 36 are permitted to rotate in relation to the manoeuvring forks 38, 50.

With the help of the manoeuvring elements 44, 58, the first manoeuvring sleeve 32 may be designed to disengage from the first or second cogwheels 12, 14 when the second manoeuvring sleeve 36 is brought into engagement with the third or the fourth cogwheels 16, 18 and vice versa. This may be achieved by letting the first cogwheel 12 constitute the first gear and the third cogwheel 16 the second gear. When shifting from the first to the second gear, the manoeuvring elements 44, 58 are controlled so that the first manoeuvring sleeves 32, 36 are disengaged from the first cogwheel 12 while the second manoeuvring sleeve 36 is brought into engagement with the third cogwheel 16. The time required for shifting between the first and second gears may thus be minimised. Similar connection and disconnection is carried out when shifting between the other gears. By placing the cogwheels 12, 14, 16, 18 on the main shaft 10, so that the cogwheels 12, 14, 16, 18 which interact with a joint manoeuvring sleeve 32, 36 have a diameter difference, the cogwheels 12, 14, 16, 18 may be placed next to each other at a small distance and still allow for the manoeuvring sleeves 32, 36 to be shifted axially with the manoeuvring forks 38, 50. The result is that the main shaft 10 and also the side shaft 22 may be made compact and have a limited length, entailing that the entire gearbox 6 may be designed as compact with a limited length.

Fig. 3 shows a detailed view of the gearbox according to Fig. 2. As shown in Fig. 3, the first manoeuvring fork 38 is designed to axially engage with the first manoeuvring sleeve 32, and the first manoeuvring sleeve 38 expands at least partly axially along a second section 40 of the main shaft 10, the second section 40 on which the second cogwheel 14 is arranged. It also shows how the second manoeuvring fork 50 is designed to axially engage with the second manoeuvring sleeve 36 and is designed to shift the second manoeuvring sleeve 36 axially along the main shaft 10. The second manoeuvring fork 50 expands at least partly axially along a third section 52 of the main shaft 10, the third section 52 on which the second cogwheel 16 is arranged.

The components and features specified above may, within the framework of the invention, be combined between different embodiments specified.

Claims

Patent claims

1. Gearbox comprising a main shaft (10) on which at least one first and one second cogwheel (12, 14) with different diameters are rotatably journalled;

an axially shiftable first manoeuvring sleeve (32), which is rotatably connected with the main shaft (10) and which is designed to engage with the first and the second cogwheels (12, 14) in order to optionally bring the cogwheels (12, 14) into engagement with the main shaft (10). a first manoeuvring fork (38), which is designed to axially engage with the first manoeuvring sleeve (32) and is designed to shift the first manoeuvring sleeve (32) axially,

characterised in that:

the first manoeuvring fork (38) expands at least partly axially along a first or a second section (42, 40) of the main shaft (10), the sections (42, 40) on which the first or the second cogwheel (12, 14) is arranged.

2. Gearbox according to claim 1, characterised in that the first manoeuvring fork (38) is connected with an axially shiftable first manoeuvring element (44).

3. Gearbox according to any of the claims 1 or 2, characterised in that the first manoeuvring element (44) is a pneumatic or hydraulic cylinder.

4. Gearbox according to any of the claims 1 or 2, characterised in that the first manoeuvring element (44) is an electric linear motor.

5. Gearbox according to any of the previous claims, characterised in that the first manoeu- vring fork (38) has a bent shape.

6. Gearbox according to any of the previous claims, characterised in that the first manoeuvring fork (38) has a radial expansion, which exceeds the radial expansion of the first or the second cogwheel (12, 14), which has the greater radius.

7. Gearbox according to any of the previous claims, characterised in that the first manoeuvring element (44) is connected with a first manoeuvring rod (46) with which the first manoeuvring fork (38) is connected.

8. Gearbox according to claim 1, characterised in that the first manoeuvring rod (46) expands substantially in parallel with the main shaft (10) and at a radial distance from the main shaft (10) which is greater than the radial expansion of the first or the second cogwheel (12, 14), which has the greatest radius.

9. Gearbox according to any of the previous claims, characterised in that a third and a fourth cogwheel (16, 18) are rotatably journalled on the main shaft (10); which through an axially shiftable second manoeuvring sleeve (36) may optionally be brought into engagement with the main shaft (10), so that the first manoeuvring sleeve (32) is designed to be disengaged from the first or the second cogwheel (12, 14) when the second manoeuvring sleeve (36) is brought into engagement with the third or the fourth cogwheel (16, 18), and vice versa.

10. Vehicle (1), characterised in that it comprises a gearbox (6) according to any of the claims 1-9.