Planetary transmission wheel drive mechanism 

Abstract
In an actuation mechanism of the planetary gear wheel, in particular for the application of torque to the drive wheels of ground vehicles docking high strength, such as trucks, tractors and the like, a pair of planetary gear sets are employed in serial connection so that one of the planetary gear sets has a gear on the drive shaft and planet carrier rotatably mounted on a fixed axis. Planetary pinion gears supported by the planet carrier mesh with a ring gear which is fixed to the hub mentioned above. The other planetary gear assembly comprises a planetary gear which is supported by an extension of the planet carrier of the first planetary gear set mentioned. The planetary gear meshes with second set of planetary gears which, in turn, are engaged with a ring gear.
The invention consists in that the extension carrying the second sun gear of said planetary gear assembly is removably connected to the planetary carrier of said first gear set while the ring gears of both planetary gear sets forming a structural unit. Thus, the drive mechanism of the planetary transmission wheel is convertible from a dual stage planetary transmission in a single stage device.
Description
Background of the Invention
This invention relates to a drive mechanism of the planetary gear wheel, in particular for the application of torque to the drive wheels for ground vehicles docking high strength, such as trucks, tractors and the like.Mechanisms transmission planetary drive wheel axle units with built in planetary transmissions are already known to the advantage of a higher torque at the end of the power flow so that the axis units of this type are particularly suitable to be included in the wheel hubs for trucks, buses and the like, allowing the use of relatively light construction.Such axis units are of considerable importance in the case of heavy vehicles like tractors and requiring very high gear transmissions or step in their wheel hubs. As is known, to satisfy such requirements multistage planetary gear transmission is used as described in the specification of British Patent No. 1,222,729 or in U.S. Pat. No. 2529330. However, the known axis units of the above type are relatively expensive because they have been constructed for special purposes and had to be developed specifically for each vehicle type.
SUMMARY OF THE INVENTION
The main object of the present invention to obviate these drawbacks and to provide a drive shaft of the planetary gear transmission unit which can form a mounting system and optionally employed to provide one-step or the transmission gears multistage planetary .The invention aims at providing a first planetary gear mechanism of a transmission gear dual-stage planetary shaft units which, by dispensing with or replacement of some components, capable of converting one type of double planetary gear transmission stage set in a single stage type these units, and vice versa.The basic idea of ​​the invention is the use of a drive shaft having a first planetary gear set and a second planetary gear set to the planet carrier of the first planetary gear assembly is provided with an interchangeable extension is a planetary gear of the second planetary gear set a-rotatably attached thereto. The invention itself is that the ring gear of the first planetary gear assembly is removably connected to a drive shaft axis and forms a structural unit with the ring gear of the second planetary gear set. It will be seen that, on one hand, for instance the separation of the first planetary gear mechanism from the drive shaft axis and on the other hand, by binding of the gear rings of the planetary gear sets both an advantageous solution of The technical problem is obtained in the background of the invention.Further details of the invention will be described with reference to the accompanying drawings which show, for example, a couple of preferred embodiments of the drive shaft according to the invention and in which:
BRIEF DESCRIPTION OF THE DRAWINGS
. FIGURE Figure 1 shows a longitudinal sectional view of a first embodiment of a drive shaft according to the invention two-stage.. 2 illustrates the hub unit shown in Fig. 1 when it becomes a single stage device.Detailed Description of the Preferred EmbodimentIn the drawing, reference character 10 designates an axle housing having axle units 12 according to the invention connected to it one of which is shown in the drawing.The drive shaft 12 shown comprises, in the usual way, a screw hole 14 which is fixed to the axle housing 10 by means of screws 16. Concentric positions of the axle housing 10 and the hollow shaft 14 are secured by a clamp assembly 14th hollow shaft 14. 14th flange adapters abuts an annular recess 10a of the axle housing 10 with the insertion of a rubber sealing ring 18 and a mounting plate 20 in a manner known per se.The hollow shaft 14 supports a shaft 22 which is rotatably-grooved as at 24. The hub 22 carries a pair of tapered roller bearings 26 and 28 by which a wheel hub 30 is rotatably supported.In the wheel hub 30 are a pair of planetary gear sets that are designated as first or inner A planetary gear set and a second planetary gear set B, respectively.The first planetary gear mechanism comprises a first sun gear 32 which is rotatably-grooved to a drive shaft 34 and meshes with the planetary gears 36. The latter are rotatably supported by pins 40 on needle bearings 42 on a first planet carrier 38 and mesh with a first ring gear 44.The planet carrier 38 is rotatably supported by the hub rotatably disposed 1 to 22 by means of ball bearings 46 and is provided with a replaceable or interchangeable extension 48 which is removably connected to the planet carrier 38 by means of screws 50.The axial position of the bolt 40 is secured by snap rings or retainers 52 and the balls 54 which engage with circumferential grooves and axial extension pins 48 and 40, respectively, as known in the art. Support discs 56 between the planetary gear 36 and the planetary carrier 38 and the extension 48 serve to prevent excessive wear.The extension 48 carries a second sun gear of the second planetary gear set B, which is rotatably connected via a splined 60. The sun gear 58 meshes with a second set of planetary pinion gears 62 of the second planetary gear mechanism B, the planetary pinion gear 62 is rotatably supported by a second support 68 in planetary needle bearings 66, and mesh with a second ring gear 70. The axial positions of the bolts 64 are determined by the balls 69 as was the case with the bolts 40 of the first planetary gear set A. The planet carrier 68 of the second planetary gear set B, is fixedly connected with the wheel hub 30 by bolts 72. Concentricity or alignment of the planet carrier 68 and the wheel hub 30 is secured in the manner described by means of a mounting flange 68a of the planetary carrier 68 which abuts against an inner cylindrical surface of the wheel hub 30.The outer end of shaft 12 is closed by a closure cap 74 which is fixed to the planet carrier 68 of the second planetary gear set B by means of threaded bolts 76. A hub 74a of the cap there is a hole 74 which receives a stub axle pin 34a or the drive shaft 34 by inserting the intermediate plates 78 to determine the mutual axial positions of the cover 74 and the drive shaft 34. The reference numeral 80 designates a slip ring between the extension 48 and the cap 74, intermediate plates 82 are provided between the cap 74 and the slip ring 80 in order to adjust the axial position of the latter. A wedge 84 prevents rotation of the slip ring 80. Position of the wedge 84 is in a manner known per se, fixed by a screw 86.The drive shaft 12 according to the invention is distinguished over the prior art by a pair of features.First, the ring gear 44 of the first planetary gear is detachably connected with the hub 22 of the drive shaft 12. For this purpose, the ring gear 44 is provided with an annular recess 44a which receives a mounting flange of the hub 22. Mutual positions of ring gear 44 and hub 22 in the circumferential direction are secured by bolts 90 fitted, while their mutual axial positions are fixed by screws 92.Secondly, the sprocket 44 of the first planetary gear forms a structural unit with the ring gear 70 of the second planetary gear set B.The top of the figure. Figure 1 shows an embodiment where the construction unit is formed by the ring gear of the first planetary gear 44 being integral with a crown gear 70 of the second planetary gear set B, two ring gears 44 and 70 are connected by a flange taper 94 between planes I and II.With the illustrated embodiment according to the bottom of the figure. 1, the ring gear 70 of the second planetary gear set B is removably connected to the ring gear 44 of the first planetary gear A. The ring gear 44 is provided as a wreath extension 44b, which is coupled to the ring gear 70 through a splined 96. Their mutual axial positions are fixed by a retainer ring or retainer 98 while an axial clearance may be provided for the purpose of promoting a uniform distribution of the load on the planet pinions 62. Moreover, the crown and extension 44b abuts against the side surface of the ring gear teeth 70 facing the first planetary gear mechanism A whereby the axial position of the latter is additionally fixed.In operation, rotation of the drive shaft 34 means a simultaneous rotation of the sun gear 32 of the first planetary gear set A whereby the planetary pinion gears 36 of the latter roll down in the ring gear 44, in turn, is attached through the hub 22 and the hollow spindle 14 to the axle housing 10 and takes up the reaction forces of a torque arising in the planet carrier 38.The planet carrier 38 is carried along the planetary pinion gears 36 and put in rotation so that the extension 48 is also fixedly connected to the planetary carrier 38 rotates. The extent of rotation 48 causes the sun gear 58 of the second planetary gear mechanism to rotate B whereby the planetary pinion gears 62 roll down in the ring gear 70 and planet carrier 68 establishes its rotation.Rotating planet carrier 68 of the second planetary gear set B transmits the torque in the wheel hub 30 which is rotatably supported by bearings 26 and roller bearings 28.In the case of a driving shaft 12 of FIG. 2 having a wheel hub 100 has to be constructed which is provided for receiving a single planetary gear assembly, the extension 48 is dispensed with and, instead, uses a connection disc 102 which is connected without rotatably with the wheel hub 100 via the planet carrier 38.In order to obviate the ring gear and drive shaft protruding from the wheel hub 100, preferably a drive shaft 34 relatively shorter will be selected and the gear rings of the previous embodiment are replaced by a ring Conventional gear 104.Since the wheel hub 100 is also the position of the planet carrier 38 is fixed with the help of the connection disc 102 and the cap 74, the ball bearing 46 used in the case of the embodiment shown in Fig. 1 is here without.

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