CS204968B2 - Pinion toothed transmission - Google Patents

Abstract

1350995 Toothed gearing; differential gear SKF INDUSTRIAL TRADING & DEVELOPMENT CO NV 29 June 1971 [30 June 1970] 30447/71 Headings F2Q and F2D In a motor-vehicle conventional type bevel differential gear 4 driven by the usual crown wheel 3 and pinion 6 from the usual propeller shaft (not shown), the pinion 6, pinion shaft 7, propeller shaft connecting flange 9 and roller bearings 15, 17 form a unit which after its assembly cannot be taken apart. As shown, when the parts are assembled together, finally putting the cylindrical sleeve 8 of flange 9 over the end of pinion shaft 7, the bearings 15, 17 are preloaded by compressing the flange 9 and pinion 6 towards each other such that when the correct preload is achieved the sleeve 8 and shaft 7 are permanently connected by electrobeam or spin welding. Fig. 2 (not shown) illustrates a similar but more compact version in which the flange (22) is formed with a sleeve (21) and is spigoted on the pinion shaft (20), the ball bearing races being directly formed in the surfaces of the pinion shaft and sleeve and in an outer housing (25, 26) shimmed and bolted to the main housing (27), the bearings being correctly pre-loaded when the shaft and sleeve are abutted and welded together. Figs. 3 to 5 (not shown) show various alternative arrangements in which the pinion and connecting flange are forged as one piece, the pre-loading of the bearings being effected by the insertion of the balls during assembly. Fig. 4 illustrates an arrangement in which the ball bearings are arranged at each end of the pinion teeth in a supporting housing having an opening through which the crown wheel engages the pinion. In Fig. 5 the pinion flange is formed as a yoke end for the propeller shaft universal joint.

Description

The invention relates to a pinion gear having a pinion, a pinion shaft provided with a connecting flange at its end adapted to be coupled to a drive shaft, a housing and rolling bearings by means of which the pinion shaft is mounted in the housing.

A pinion gear of this type is known from U.S. Patent No. 1,956,237 and U.S. Pat

These pinion gears are used, for example, in automobiles to transmit the driving torque from a longitudinally oriented shaft to transversely oriented shafts for driving the wheels, the toothed pinion engaging a gearwheel in the gearbox.

Gears of this type shall be able to withstand torsional loads and axial loads of considerably variable sizes. This leads to the need to pre-load the pinion shaft bearings and precisely adjust the pinion relative to the toothed ring gear. In the embodiment of U.S. Pat. No. 3,385,133, the preload is performed by means of a screw nut through which the sleeves pass, the sleeve forming part of the coupling means bringing the bearing element into axial compression. Adjustment of the pinion with respect to the ring gear is achieved by means of rings inserted between the shoulder of the bearing ring and the housing.

In this known arrangement, the adjustment is influenced by the amount of preload, so that this operation is difficult, requires high skill, demands time and is extremely difficult to repair. In the design of U.S. Pat. No. 1,956,237, the preload of the bearing is achieved by selecting the dimensions of the elements and heating the individual parts during assembly. However, the bearing elements are subjected to an axial load by a screw nut connecting the coupling means to the pinion shaft, so that the adjustment of the pinion with respect to the ring gear, also achieved in this case by inserting the ring inserts, is also influenced by the preload.

When preloading and positioning, account must also be taken of the rigidity of the components, in particular with regard to radial bending and axial elastic deformation, deformation due to surface contact of individual parts, thermal expansion during operation of the transmission and manufacturing tolerances between the individual parts forming construction, such as pinion shaft, housings, seats and bearings for the bearings and bearings themselves.

204988

SUMMARY OF THE INVENTION It is an object of the invention to provide a pinion gear transmission in which the preload does not affect the adjustment of the transmission. This object is achieved by a pinion gear having a pinion, a pinion shaft provided at its end with a connecting flange adapted to be coupled to a drive shaft, a housing and rolling bearings by means of which the pinion shaft is supported in a housing in which the pinion shaft, pinion , the connecting flange and the internal grooves of the roller bearings form an integral element. Preload of the bearing is thus achieved in the manufacture of this integral element, so that only the action to be performed is to adjust the transmission.

According to the invention, the integral element may be formed of one piece of material, so that the respective assembly is formed of the one piece of material, the bearing balls and the outer bearing grooves.

It is also possible for the unitary element to be formed of more than one piece of material connected to each other by welding. In this case, the integral element has two main parts between which the bearing elements, including the rings of the outer bearing grooves, are fixedly fixed in the axial direction.

If a single piece of material is used, it is preferable that the integral element is formed as a hollow body closed at the end on which the pinion is located. In this way, rigid assemblies with a small axial dimension can be obtained.

Although in some embodiments of the pinion assembly according to the invention it is possible to use separate bearing race rings, it is preferable to make these grooves by machining directly in corresponding surfaces of a portion or portions of the blank itself, thereby greatly reducing the number of manufacturing tolerances to be considered.

The whole construction may be such that the diameter of the pitch circle of the bearing located between the pinion and the coupling means is greater than the outside diameter of the circle described by the pinion teeth. This increases bearing capacity and in some cases simplifies assembly.

This arrangement allows a very small axial length of the assembly, the bearing being as close as possible to the gear teeth. It is also advantageous to dimension the individual elements such that the inner diameter of the bearing cage is larger than the outer diameter of the circle described by the pinion teeth, thereby also facilitating the mounting of the bearing.

In all embodiments of the invention, the axial length of the pinion gear is considerably reduced compared to the known embodiments, the degree of reduction of this length depending on the particular design as well as whether or not the bearing grooves are designed with separate elements.

In all embodiments of the invention, pre-loading is performed during manufacture. In the case of repair, the cheap pinion assembly na4 is paid for by another one, eliminating the need for qualified work. The number of places where contact surface deformation can occur is reduced, as is the number of places where machining tolerances are of greater importance. Large diameters are possible, and the smaller axial length reduces the radial bending under the load occurring between the gears of the transmission and thus contributes to an increase in stiffness. Shortening the length also reduces thermal expansion.

The design of the pinion assembly according to the invention makes it possible to use all kinds of cheaper production processes. In all cases, the cardan joint can be integral with the coupling flange because the screw nut is no longer present at the end of the pinion shaft.

Large diameters of bearing balls and pitch circles can be used, and with a small axial length of the assembly, the working angle can be selected such that the working line of forces passes through the area where the working angle intersects the shaft axis. reducing bending forces.

The transmission function is no longer impaired by the weakness of the components due to the influence of tolerances and elastic deformation, so that higher accuracy can easily be achieved.

BRIEF DESCRIPTION OF THE DRAWINGS The invention is explained in more detail below with reference to the accompanying drawings, in which: FIGS. 1 to 5 show axial sections of various embodiments of the invention.

The embodiment of FIG. 1 differs from the known designs at least in all the embodiments shown. As can be seen from the figure, the pinion gear has a housing 1, in which a ring gear 3, connected to a differential 4, is mounted by means of bearings 2. The pinion 6 is supported by bearings in a projecting part 5 of the housing 1.

According to the known solution, the shaft and the housing are provided with bearings and the bearings have outer and inner rings of the bearing grooves, the coupling means for connection to the drive shaft being fixed to the grooved end of the pinion shaft by a nut screwed on the threaded end of the shaft. This nut plays an important role in achieving pre-load of the bearings.

In the construction according to FIG. 1, the pinion 6 is supported by a shaft 7 and the connecting means is formed by a sleeve 8 provided with a connecting flange 9. The housing 1 is in its part 5 provided with a cylindrical passage 10. by grooves 66, 67 of two bearings for receiving the shaft 7, spaced axially apart. The rings 11, 12 are kept apart from each other by a cylindrical shaft 13, the ring 11 being supported by a shoulder 14 formed in the housing body 1. The corresponding rings with internal bearing 204988 grooves, namely the ring, are firmly connected to the pinion shaft 7. 15 with an inner bearing groove 68 supported by the shoulder 16 on the pinion 6, and a ring 17 carrying a second inner bearing groove 69 that rests on the sleeve 8 of the connecting flange 9.

After assembling the above-mentioned parts, the final process of which is to slide the sleeve 8 onto the cylindrical end of the shaft 7, the bearing is subjected to a preload by pushing the coupling flange 9 and the pinion against each other. When the desired pre-load rate is reached, the connecting flange 9 is inseparably attached to the shaft 7 by welding the sleeve 8 by means of a weld 69. The assembly thus obtained is secured in the housing 1 by means of two half securing rings 18.

The axial length of this embodiment is reduced as compared to known pinion assemblies, since the splined shaft end with the tongue and the threaded end of the shaft for screwing the nut are eliminated. The design of the shaft itself is simple because it has only a cylindrical outer surface.

In the example of Fig. 1 they are shown as ball bearing rolling elements, but it will be appreciated that other rolling elements may also be used.

Giant. 2 shows an embodiment of the invention having a substantially smaller length in the axial direction. In this embodiment, the pinion 19 and the shaft 29 form an integral element and the connection means again consists of a housing 21 and a flange 22 which are inseparably connected to the shaft 20 by a weld 61.

In this embodiment, the inner grooves 23 and 24 of both ball bearings are machined in the pinion shaft and sleeve 21 material itself. The outer part of the assembly is formed by a housing 25 with a flange 26 that allows the assembly to be attached to the housing 27. The outer grooves 28, 29 can also be formed by direct machining of the material of the sleeve 25. The bearing is further provided with a gasket 30. In this embodiment of the invention, the sleeve 21 and the shaft 20 on each other in the axial direction • abut and are machined so precisely that the required pre-load is achieved when the two parts are not mutually engaged, • weld.

This embodiment is substantially shorter in the axial direction than the previous one. The only facets whose tolerances play a role are those faced with balls.

Giant. 3 shows an embodiment in which the pinion 62, the shaft 42 and the connecting flange 63 form a single integral element formed by pressing or forging steel into a hollow body shape. The cavity extends along almost the entire length of the integral element. The inner grooves 41 for the bearing balls are formed by machining in the shaft body itself and the same applies to the outer grooves in the flange housing 43 that serves to connect the assembly to the housing 44.

The axial length of this embodiment is relatively small and the diameter relatively large. As can be seen from FIG. 3, the gear gear load line 45 and the working line 4a of one of the rolling bearings intersect on the axis 47 at a single point, indicating that very little bending stresses occur in the shaft 42 and thus ball bearings can be used. bearings with high load capacity and large diameter.

Giant. 4 shows a further development of the design principle o-br. 3, characterized in that a hollow forged body is used in which the pinion gear is machined between the inner grooves 48 and 49 of the two ball bearings. The outer sleeve 50 with the flange 51 is of course of greater axial length and is provided with an opening 52 through which the ring wheel passes and engages the pinion 53 of the pinion 64. In this case, the shaft 70 is reduced to two short axial sections 70a, 70b in corresponding internal grooves 48 and 49.

The preload is achieved in both embodiments according to FIGS. 3 and 4 by inserting balls.

As shown in FIG. 3, the pitch diameter of the largest bearing is greater than the diameter of the circumscribed pinion gear. It will be appreciated that this pitch diameter may be even greater than that shown in FIG. 3. The inner diameter of the ball bearing cage is such that the cage can easily be pulled over the pinion gear.

Giant. Fig. 5 shows an embodiment according to the same principle as in Figs. 3 and 4, but with the exception that the eye-shaped attachment elements extend from the flange 55 of the molded or forged body so that the pivoting parts 56 of the cardan joint can be attached thereto.

Otherwise, as in previous embodiments, the molded or forged body includes a shaft forming portion 54 and a pinion forming portion 65.

The bearing assembly is provided with seals 58 to provide a unitary unit from which lubricant cannot flow and in which the bearing is protected from gears from gearing wear.

Claims (4)

A pinion gear having a pinion, a pinion shaft provided with a connecting flange at its end adapted to be coupled to a drive shaft, a housing and roller bearings by means of which the pinion shaft is mounted in a housing, characterized in that the shaft (7, 20) , 42, 54) the pinion (6, 19, 62, 64, 65), the pinion (6, 19, 62, 64, 65) and the connecting flange (9, 22, 55 63) form an integral element comprising internal grooves (68 , 69; 23, 24; 41, 48, 49) antifriction bearings. VYNALEZU 2. The pinion gear according to claim 1, wherein the integral element is formed from a single piece of material. 3. The pinion gear according to claim 1, wherein the integral element is formed from more than one piece of material connected to each other by welds (60, 61). 4. The pinion gear according to claims 1 to 3, characterized in that the integral element is a hollow body closed at the end on which the pinion (19, 62, 64, 65) is located.