Reduction gearbox

Abstract

A reduction gearbox for vehicles whose chassis is equipped with a central support tube, designed for installation in the front or rear section of the drivetrain, in which the torque generated by the engine's drive unit is transmitted to the wheels via a cardan shaft. The core of the invention consists in the gearbox comprising only a drive shaft and an output shaft, wherein a driving gear is arranged on the drive shaft and a driven gear on the output shaft, wherein - the driving gear and the driven gear are in mesh with each other and are either mounted on the shafts by means of longitudinal teeth or are an integral part of the shafts, - the housing of the reduction gear is symmetrical to the plane defined by the axes of the input shaft and the output shaft, and the shafts are supported in the housing by means of two pairs of tapered roller bearings, - the drive shaft is connected to the output flange of the drive unit via a connecting flange using a cardan shaft, so that the axis of the drive shaft is not aligned horizontally or vertically relative to the position of the output flange, - the housing is connected on one side and directly to the central support tube by means of an integrated flange, whereby the axis of the support tube is not aligned with the position of the output flange of the drive unit, - the output shaft is connected to the remaining part of the drive train via internal or external teeth in the central support tube.

Description

Technical field

[0001] The invention belongs to the field of the automotive industry, in particular to vehicle design and especially to drive systems for heavy trucks, and relates to a new design of a reduction gear for vehicles whose chassis is equipped with a central support tube. State of the art

[0002] In the design of chassis constructions for trucks, reduction gearboxes are very frequently used to transfer the torque generated by the drive unit to the wheels.

[0003] German patent DE 44 20 305 (analogous to EP 686 788 - Reduction gearing for engine or motor) describes a gearbox that is rigidly connected to the engine by means of integrated flanges, with the input and output shafts arranged coaxially, thus preventing any change in the length of the driveshaft. The gearbox consists of an engine-side input shaft, an axially parallel output shaft on which a gear is mounted, a countershaft, and a gearbox housing. Recesses for receiving rolling bearings are formed in the inner transverse partition and the end wall of the gearbox housing, with a further recess provided at the end edge of the housing shell. The overall gearbox design includes a sealed, inclined separation plane with a through-opening for the input shaft, thereby ensuring the gearbox can be easily mounted.

[0004] Drive solutions using reduction gears are also known, arranged at various angular positions relative to the plane perpendicular to the vehicle's longitudinal axis; an example is the solution according to DE 38 28 083 (four-wheel drive system for a vehicle). This system, which can be locked if required, provides drive for vehicles with four driven wheels. It comprises an intermediate axle differential and an auxiliary gearbox connected to the axles via cardan shafts. This solution has one input shaft and two output shafts (for the front and rear axles), and the auxiliary gearbox includes an intermediate gear, which increases the gearbox's installation space requirement. Furthermore, the solution allows the relative arrangement of the auxiliary gearbox and axle gearboxes with respect to the cardan shafts to be selected, with the cardan angles being adjusted by angling the axis of the output shaft for the front axle.The gearbox is lubricated by immersion and splash lubrication; the oil is distributed to the individual components via channels.

[0005] From US patent 11174938 (Transfer structure for vehicle), an auxiliary transmission for a vehicle is known that allows for the retention of a stable quantity of lubricant in the clutch chamber and maintains the cooling effect for the clutch by mixing the lubricant, regardless of the vehicle's longitudinal tilt. The auxiliary transmission comprises a housing with a transmission chamber in which a first and a second meshing gear are arranged, a clutch chamber containing a clutch coaxial with the first gear, a supply channel that introduces lubricant from the transmission chamber into the clutch chamber, and a return channel through which the lubricant is returned from the clutch chamber to the transmission chamber.The return channel is inclined downwards from an opening that opens in the lower part of an intermediate section of the clutch chamber in the longitudinal direction of the vehicle, towards the gearbox chamber to an oil drain opening that opens into the gearbox chamber.

[0006] Document CZ131859 ​​describes an arrangement of a transmission system for commercial vehicles with four driven axles and independent suspension of all wheels, wherein the transmission system is divided into an assembly unit of the front unit and an assembly unit of the rear unit and the drive of the reduction gear is provided by means of a driveshaft from the intermediate differential between the front and rear axles.

[0007] Also known is the solution according to US11285808 (Modular drive train and vehicle comprising such a drive train), which describes a vehicle with a transmission, a module of a central support tube and at least one axle with axle differential, wherein the axles are mounted on the support tube module and a longitudinal differential transmits the drive torque provided by the transmission to at least one axle, as well as a primary axle differential integrated into the drive train between the longitudinal differential and the axle.

[0008] The aim of this solution is to present a new chassis concept for transport vehicles with a central support tube. A simple reduction gearbox is integrated in such a way that it has a flange for the driveshaft on the input side and a flange for connection to the central support tube on the output side, thus eliminating the need for intermediate adapters. The gearbox comprises only two shafts: the input shaft and the output shaft. A further objective of this new solution is to design the connection between the driveshaft, the drive unit, and the reduction gearbox on the chassis in such a way that the gearbox can be used to drive either the front or rear section of the vehicle's drivetrain, while simultaneously reducing the overall installation space of the drivetrain. Subject matter of the invention

[0009] The problem is solved by a reduction gearbox for vehicles whose chassis is equipped with a central support tube, designed for installation in the front or rear section of the drivetrain, in which the torque generated by the engine's drive unit is transmitted to the wheels via a cardan shaft. The core of the invention consists in the fact that the gearbox comprises only one input shaft and one output shaft, wherein a driving gear is arranged on the input shaft and a driven gear on the output shaft, such that - the driving gear and the driven gear are in mesh and are either mounted on the shafts by means of longitudinal teeth or are an integral part of the shafts, - the housing of the reduction gear is symmetrical to the plane defined by the axes of the input and output shafts, and the shafts are supported in the housing by means of two pairs of tapered roller bearings, - the drive shaft is connected to the output flange of the drive unit via a connecting flange using a cardan shaft, wherein the axis of the drive shaft is not aligned horizontally or vertically with respect to the position of the output flange, - the housing is connected on one side and directly to the central support tube by means of an integrated flange, whereby the axis of the support tube is not aligned with the position of the output flange of the drive unit, - the output shaft is connected to the remaining part of the drive train via internal or external teeth in the central support tube.

[0010] In an advantageous embodiment, collection trays are arranged one above the other on the inner walls of the housing, which collect the oil of the lubrication system running down the housing walls, capture the oil wiped off by the driving gear and supply it to the tapered roller bearings via channels.

[0011] The proposed solution achieves a new and enhanced effect: By equipping the reduction gear with a flange for the cardan shaft at the input and a flange for connection to the central support tube at the output, while simultaneously limiting the design to only the input and output shafts and using a housing symmetrical in the plane defined by their axes, the articulation angle of the cardan shaft – determined by the relative positions of the flanges on the drive unit and the reduction gear – can be reduced by tilting the housing by the angle α, which can be up to 45°.Due to the aforementioned symmetry of the reduction gearbox housing, the gearbox can be used to drive either the front or rear section of the vehicle's drivetrain. The direct, one-sided connection of the gearbox to the flange of the central support tube allows the drive unit to be positioned lower, at the same level as the central support tube. This lowers the vehicle's center of gravity and increases the available space for bodywork without compromising ground clearance. A further innovation is the design of a new gearbox lubrication system that operates without an oil pump or partitions and utilizes oil scraping directly from the gears. This increases the oil flow to the individual components, thereby improving lubrication and cooling.The positioning of the collection trays allows for both a lateral tilt of the reduction gear and a longitudinal tilt of the vehicle when driving uphill and downhill. Explanation of the drawings

[0012] A specific embodiment of the invention is schematically illustrated in the accompanying drawings, wherein Fig. Figure 1 shows a diagram of the rear section of the vehicle's drivetrain with a built-in reduction gearbox in side view, Fig. 2 a diagram of the rear section of the vehicle's drivetrain with built-in reduction gearbox according to Fig. 1 shows a top view, Fig. 3 a front view of the rear section of the vehicle's drivetrain with the reduction gearbox according to Fig. Figure 1 shows the inclination of the central support tube on the horizontal plane. Fig. 4 shows a detailed diagram of the reduction gear, Fig. Figure 5 shows a schematic vertical section through the reduction gear with a representation of its lubrication system and Fig. Figure 6 shows a side view of the front section of the vehicle's drivetrain with a built-in reduction gearbox.

[0013] Drawings illustrating the invention presented and the examples of specific embodiments described below do not in any way limit the scope of protection mentioned in the definition, but merely explain the subject matter of the invention. Examples of the implementation of the invention

[0014] The reduction gear 1 for vehicles whose chassis is equipped with a central support tube 2 is designed for installation in the front or rear section of the drivetrain. An exemplary embodiment of the rear section of the vehicle's drivetrain is shown in Fig. 1 and Fig. Figure 2 shows that, firstly, the drive shaft 11 of the reduction gear 1 is connected to the output flange 41 of the drive unit 4 via a connecting flange 12 and a cardan shaft 3, and secondly, the housing 15 of the drive unit 4 is directly connected to the central support tube 2 by means of an integrated flange (not shown and not labeled), to which one or more axles 6 of the wheels 7 are also attached. The housing 15 of the reduction gear 1 is symmetrical about the plane defined by the axes of the drive shaft 11 and the output shaft 13; the shafts are supported in the housing 15 by means of two pairs of identical tapered roller bearings 16. The transmission comprises only the two aforementioned shafts 11, 13, wherein a driving gear 17 is arranged on the drive shaft 11 and a driven gear 18 is arranged on the output shaft 13, wherein these gears 17, 18 are in mesh.The gears 17, 18 are mounted on the shafts 11, 13 either by means of longitudinal teeth or – depending on the gear size and manufacturing technology – can be an integral part of the shafts 11, 13. The output shaft 13 is connected to the remaining part of the drive train in the central support tube 2 via an internal or external toothing (not shown), as required.

[0015] To compare the change in the joint angle of the cardan shaft 3, the relative positions of the flange 41 of the drive unit 4 and the connecting flange 12 of the reduction gear 1 are shown in Fig. 2 and Fig. Figure 3 shows the angle α, the tilt angle of the reduction gear 1 relative to the vehicle's longitudinal axis, which can be up to 45°. Dimension "A" indicates, in the vertical direction, the distance between the axis of the output flange 41 of the drive unit 4 and the axis of the central support tube 2. When the reduction gear 1 is used, this axis distance is reduced to dimension "a". Dimension "B" indicates, in the horizontal direction, the distance between the axis of the flange 41 of the drive unit 4 and the axis of the drive shaft 11 of the reduction gear 1 when mounted without tilt. When the reduction gear 1 is tilted, this distance is reduced to dimension "b". The purpose of tilting the reduction gear 1 is to find an arrangement that favorably influences the articulation angle of the cardan shaft 3, thus reducing the installation space of the vehicle's drivetrain.

[0016] The lubrication system of the reduction gear 1 according to Fig. 5 is implemented without an oil pump by means of splash lubrication. The gears 17, 18 of the reduction gear 1 spray oil onto the walls of the housing 15. Oil running down the housing walls 15 is collected in superimposed collecting trays 19, which are formed on the inner walls of the housing 15, for the tapered roller bearings 16 of the drive shaft 11 and the output shaft 13. To increase the amount of oil flowing into the tapered roller bearings 16 of the drive shaft 11, the upper collecting trays 19 simultaneously draw oil from the driving gear 17. The lower tapered roller bearings 16 are additionally lubricated by immersion lubrication in the oil located at the bottom of the housing 15. Fig. The oil channels 20 and the direction of oil flow are shown by arrows.

[0017] The described embodiments of the reduction gear 1 do not represent the only possible solutions according to the invention; for example, the shape of the housing 15 can be adapted to the shape and size of the installation space. Likewise, the tapered roller bearings 16 for supporting the two shafts 11, 13 can be replaced by other types of rolling bearings. Commercial applicability

[0018] The reduction gearbox is designed for use in the drive trains of heavy trucks equipped with a central support tube, where the torque generated by the engine's drive unit is transmitted to the wheels via a cardan shaft. QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] DE 44 20 305

[0003] EP 686 788

[0003] DE 38 28 083

[0004] US 11174938

[0005] CZ 131859 ​​

[0006] US 11285808

[0007]

Claims

[1] Reduction gear (1) for vehicles whose chassis is equipped with a central support tube (2), designed for installation in the front or rear section of the drive train, in which the torque generated by the drive unit (4) of the engine is transmitted to the wheels (7) by means of a cardan shaft (3), characterized by , that it comprises only a drive shaft (11) and an output shaft (13), wherein a driving gear (17) is arranged on the drive shaft (11) and a driven gear (18) is arranged on the output shaft (13), wherein - the driving gear (17) and the driven gear (18) are in mesh and are either mounted on the shafts (11, 13) by means of splined shaft teeth or are an integral part of the shafts (11, 13), - the housing (15) of the reduction gear (1) is designed symmetrically to the plane defined by the axes of the drive shaft (11) and the output shaft (13) and the shafts are supported in the housing (15) by means of two pairs of tapered roller bearings (16), - the drive shaft (11) is connected to the output flange (41) of the drive unit (4) via a connecting flange (12) using a cardan shaft (3), so that the axis of the drive shaft (11) is not aligned horizontally or vertically with respect to the position of the output flange (41), - the housing (15) is connected on one side and directly to the central support tube (2) by means of an integrated flange, wherein the axis of the support tube (2) is not aligned with the position of the output flange (41) of the drive unit (4), - the output shaft (13) is connected to the remaining part of the drive train in the central support tube (2) via internal or external teeth. [2] Reduction gear (1) according to claim 1, characterized by , that collection trays (19) arranged one above the other are formed on the inner walls of the housing (15) to collect the lubricating oil flowing down the housing walls (15), to wipe oil from the driving gear (17) and to drain the oil through channels (20) into the tapered roller bearings (16).

Images