Method For Fixing A Bushing In A Through Bore Of A Gear Of The Idler Gear Assembly

Abstract

An idler gear assembly, as well as an internal combustion engine comprising the idler gear assembly, and a method for fixing a bushing in a through bore of a gear of the idler gear assembly

Claims

1. Method for fixing a bushing in an inner through bore of a gear of an idler gear assembly, said gear being provided with a circular groove provided in the internal surface of the bore, said bushing being provided with a circular radial outward deformation located in said groove, said method comprising: press-fitting of the bushing into the bore; and making the circular radial outward deformation in the bushing during or after the press-fitting operation, wherein the circular radial outward deformation is made by pressing the internal surface of the bushing radial outward by means of a circular rolling operation.

2. Method for fixing a bushing in an inner through bore of a gear of an idler gear assembly, said gear being provided with a circular groove provided in the internal surface of the bore, said bushing being provided with a circular radial outward deformation located in said groove, said method comprising: press-fitting of the bushing into the bore; and making the circular radial outward deformation in the bushing during or after the press-fitting operation, wherein the circular radial outward deformation is made by pressing the internal surface of the bushing radial outward by means of forcing pins after the bushing is press-fitted into the bore of the gear.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The invention will be further elucidated below on the basis of drawings. These drawings show an embodiment of the idler gear assembly according to the present invention. In the drawings:

[0022] FIG. 1 shows a valve timing gear transmission of an internal combustion engine;

[0023] FIG. 2 is an idler gear assembly of the valve timing gear transmission shown in FIG. 1;

[0024] FIG. 3 is a cross section of the idler gear assembly shown in FIG. 2;

[0025] FIG. 4 is a detail of the idler gear assembly showing additional axial fixation means;

[0026] FIG. 5 is the idler gear assembly in cross section just before forcing the wall of the bushing radial outward; and

[0027] FIG. 6 is the idler gear assembly in cross section during forcing the wall of the bushing radial outward.

DETAILED DESCRIPTION OF THE DRAWINGS

[0028] In FIG. 1 a valve timing gear transmission of an internal combustion engine is shown. For the sake of clarity, only the valve timing gear transmission 1, the camshaft 3, crankshaft 5 and water pump 7 of the combustion engine are shown. The valve timing gear transmission 1 has a cam gear 9 connected to the cam shaft, a crank gear 11 connected to the crankshaft and an idler gear assembly 13 connecting both gears and being present on an idler shaft 14.

[0029] In FIGS. 2 and 3 the idler gear assembly 13 is shown in perspective view and in cross section. The idler gear assembly 13 has a compound gear 15 consisting of two gear wheels 17 and 19. One of these gear wheels 17 has a collar 21 on which the other gear wheel 19 is press-fitted. The gear wheels are provided with helical toothing 23 and a through bore 25. Into the bore 25 a thin walled bushing 27 is press-fitted.

[0030] The idler gear assembly 13 is provided with additional axial fixation means to fixate the bushing 27 in the bore 25 in axial direction. These additional axial fixation means are constituted by a circular radial outward deformation 29 of the wall 31 of the bushing 27 and a circular groove 33 provided in the internal surface 35 of the bore 25. In FIG. 4 a detail of the idler gear assembly indicated by arrow A in FIG. 3 is showed. This detail shows the additional axial fixation means. The radial outward deformation 29 of the bushing is located in the groove 33 and constitutes an oil groove.

[0031] This outer radial deformation 29 is made by pressing the internal surface 35 of the bushing 27 radial outward by means of a circular rolling operation after the bushing is press-fitted into the bore 25 of the gear. Then the inner diameter of the bushing is machined, grinded and/or honed.

[0032] In FIGS. 5 and 6 a method of forcing the wall 31 of the bushing radial outward into the groove 33 provided in the internal surface 35 of the bore 25 is shown. In FIG. 5 the idler gear assembly 13 is shown in cross section just before forcing and in FIG. 6 the idler gear assembly 13 is shown during forcing the wall of the bushing 27 radial outward. The tool 37 for forcing the wall of the bushing consists of a hollow cylinder 39 with a moving core 41 inside. Around a part of the core a conical ring 43 is present and cooperates with conical elements 45 to which pins 47 are fixed. By moving the core 41 the pins 47 are moved radial outward and force the wall of the bushing 27 into the groove 33 in the bore 25.

[0033] Although the present invention is elucidated above on the basis of the given drawings, it should be noted that this invention is not limited whatsoever to the embodiments shown in the drawings. The invention also extends to all embodiments deviating from the embodiments shown in the drawings within the context defined by the claims. Instead of forcing the wall of the bushing radial outward with the use of pins as shown in FIGS. 5 and 6, the wall could also be deformed by a rolling method as for example described in DE849942C.