GB2095792A

GB2095792A - Flange joint

Info

Publication number: GB2095792A
Application number: GB8112053A
Authority: GB
Original assignee: Bayerische Leichtmetallwerk Graf Bluecher Von Wahlstatt KG
Current assignee: Bayerische Leichtmetallwerk Graf Bluecher Von Wahlstatt KG
Priority date: 1981-03-31
Filing date: 1981-04-16
Publication date: 1982-10-06
Also published as: DE3112923A1; EP0062109A1; JPS57173617A

Description

SPECIFICATION Flange joint The invention relates to a non-permanent flange joint for the transmission of high torques, more especially a flange joint on rotating shafts, whose flanges are interlocked within their connection ends and are held together by means of connecting bolts which are placed through bolt holes in both flanges. A flanged joint of this kind serves for the transmission of particularly high torques, mainly for the drive transmission between the shaft of motor vehicles and the engine, gearbox, converter axles, etc. thereof. There are known, particularly in connection with lorries and military vehicles, gearbox flanges whose connection ends are interlocked in a staggered manner in some zones. However, interlock arrangements of this kind only carry up to approximately 70% of their profile crosssections which are subject to shearing stresses, so that the surface of the connection ends that is available for interlocking is frequently not sufficient for the transmission of very high torques. In such cases, one skilled in the art manages with the additional provision of clamping sleeves in the interior of the bolt holes or of dowel pins in addition to the fastening bolts. Furthermore known are flange joints which are provided with a metallic sealing, in that a circular rib having a spline profile on one flange is keyed into a corresponding wedge-shaped annular groove in the other flange (German Patent Specification 539 039). Herein, the holes for the flange bolts are, for sealing reasons, taken through the rib and the groove without cutting the sealing spline flanks. The splined rib and the key groove do not contribute to the transmission of a torque. As compared to the prior art, the task underlying the invention is to provide a nonpermanent flange joint for the transmission of high torques which is easy to manufacture and to fit and which is distinguished by a space-saving interlocking of its connection ends so that, related to the flange diameter, the torque to be transmitted can be increased as compared to the known staggered interlock arrangement. According to the invention, this problem is solved in that, at least in the area of several supporting zones of the flange joint, a conical elevation of one flange engages in a corresponding conical depression in the other flange, and in that the bolt holes are provided within or close to the supporting zones in such a way that the two flanges are supported on each other, against the pull exerted by the connecting bolts, in the area of the conical flanks of the supporting zones. The joint proposed according to the invention requires relatively few supporting zones, at least two and preferably four. Therefore, it is possible to dimension the elevations and the depressions in adaptation to the torque to be transmitted. Within the framework of the relevant DIN specifications for flange dimensions, there come about, by using the proposal according to the invention, increases in the torque transmission of up to 40% compared with the known staggered interlock arrangement which is machined by stock removal. Within the scope of the invention, the bolt holes may be provided either within the supporting zones or close to the supporting zones. Due to the radial support of the flanges in the area of the supporting zones or rather of the elevations/depressions provided there, it is possible to keep the bolts free from shearing forces. As a result of the mere subjection to tension of the connecting bolts, there is no need to use any high-strength bolt sets. In addition, the positive joint in the area of concrete supporting zones, as proposed according to the invention, causes a high degree of reliability of the torque transmission to be attained. It is precisely due to the increased reliability of this flange joint that a particularly wide field of application is provided therefor, even outside the motor vehicle industry, e.g. in connection with highly loaded earth moving machines, crane vehicles, but also in connection with steering and shifting joints which are subject to stringent safety requirements. The flange joint according to the invention can be produced particularly advantageously by the precision forging method by means of forming in a hot state and subsequent calibrating in a cold state with the connection ends of the flanges ready for installation. The fibre flow attained during forging promotes the shearing strength of the elevations. The production by means of forging is substantially cheaper than the production of an interlocking arrangement of the connection ends of the flanges by means of cutting. It is precisely the use of the forging method for the production of the flanges which allows the fabrication of any desired cross-sectional shapes of the elevations/depressions. A constructional form of the supporting zones which is preferred because of its high degree of strength related to the cross section consists in that the design of the elevation is frusto-conical and that of the depression corresponds thereto but has a bottom diameter that is somewhat smaller than the top diameter of the elevation. The elevation engages in a cam-like manner in the depression, the elevation and the depression being supported on each other under the effect of the pull exerted by the fastening bolts in the zone of their conical flanks, there being of course maintained a small clearance between the top of the elevation and the bottom of the depression.For releasing the joint, there are used known 'per se' forcing threads, into which appropriate set screws are screwed. According to a preferred constructional form of the invention, provision is made for the bolt holes to be drilled through the centres of the supporting zones, in other words right through the elevations and depressions. This ensures a direct action of the bolt pull on the positive interengagement of the flanges in the area of the supporting zones. But even if the bolt holes are drilled outside the 60 supporting zones, an almost loss-free transmission of the bolt pull can be attained, in that, according to another proposal of the invention, the supporting zones are so arranged that they are distributed in pairs over the flange circumference 65 and that a fastening bolt is provided between each pair. Hereinafter, some exemplified embodiments of the invention will be explained with reference to the drawings, in which:- 70 Fig. 1 shows a view of a flange with four supporting zones, in the centre of which there is seated respectively one connecting bolt; Fig. 2 shows a view of a flange with four supporting zones and connecting bolts outside 75 thereof; Fig. 3 shows a section along III-III in Figure 1; Fig. 4 shows a section along IV-IV in Figure 2; Fig. 5 shows a section along V V in Figure 2; and 80 Fig. 6 shows a section along VI-VI in Figure 1. Figure 1 shows a section through a shaft part 1 including a flange 2. In the area of the flange 2, there are provided four supporting zones 3, in whose centres there sit connecting bolts 4. The 85 four supporting zones are arranged opposite to one another in pairs.After the connecting bolts 4 have been unscrewed, the joint of the two flanges can be released by means of the forcing threads 5 provided between the supporting zones. Figure 6 90 shows a section taken in the area of a forcing thread 5. In order to release the right-hand flange 2 from the left-hand flange 6, an appropriate screw is screwed into the forcing thread 5 until the flanges which positively interengage in the 95 area of the supporting zones 3 are released from each other. Such an interlocking connection is shown in Figures 3 and 4, a conical elevation 7 engaging in a corresponding depression 8. In Figure 3, a connecting bolt 4 has been taken 100 through the centre of the supporting zone. This bolt sits with a radial clearance in corresponding bolt holes 10, 11 in the two flanges 2, 6.In Figure 4, the elevation 7 has not been drilled so that the shearing load can be still increased. Only in the 105 area of the depression 8 is there provided a forcing thread 5 in the flange 2. As shown in Figures 3 and 4, the elevation 7 and the depression 8 tightly bear against each other in the area of their conical flanks, that is to 110 say the supporting zones alone, without the assistance of the connecting bolts 4, provide the mutual radial support of the two flanges along the lines of the torque to be transmitted. The section shown in Figure 5 illustrates a connecting bolt 4 115 arranged outside the supporting zone.

Claims

60 1. A non-permanent joint for the transmission of high torques, more especially a flange joint on rotating shafts, whose flanges (2, 6) are interlocked within their connection ends and are clamped together by means of connecting bolts

65 (4) which are placed through bolt holes (10, 11) in both flanges, characterised in that the area of several supporting zones (3) of the flange joint, a conical elevation (7) of one flange (6) engages in a corresponding conical depression (8) in the other

70 flange (2), and in that the bolt holes (10, 11) are provided within or close to the supporting zones (3) in such a way that the two flanges (2, 6) are supported on each other against the pull exerted by the connecting bolts (4) in the area of the

75 conical flanks of the supporting zones (3).
2. A joint as claimed in Claim 1, characterised in that the design of the elevation (7) is frustoconical and that of the depression (8) corresponds thereto but has a bottom diameter that is

80 somewhat smaller than the top diameter of the elevation.
3. A joint as claimed in Claim 1 or 2, characterised in that the bolt holes (10, 11) have been drilled through the centre of the respective

85 supporting zone (3).
4. A joint as claimed in Claims 2 and 3, characterised in that the mean diameter of the elevation (7) is approximately three times the diameter of the bolt hole (10) which has been

90 drilled in the centre of the elevation (7).
5. A joint as claimed in Claim 1 or 2, characterised in that if the bolt holes are drilled outside the supporting zones (3), the axial distance thereof from the supporting zones (3) is

95 between twice and four times the diameter of the bolt holes.
6. A joint as claimed in Claim 1, characterised in that the supporting zones (3) are arranged so as to be distributed in pairs over the flange

100 circumference, and in that a connecting bolt (4) is provided between each pair.
7. A joint as claimed in one of Claims 1 to 6, characterised in that the flanges (2, 6) are produced by the precision forging method by

105 means of forming in a hot state and subsequent calibrating in a cold state with connection ends that are ready for installation.
8. A joint as claimed in Claim 7, characterised in that the depressions (8) are additionally after110 machined by stock removal.
9. A non-permanent joint for the transmission of high torques, substantially as hereinbefore described with reference to and as illustrated in Figs. 1, 3 and 6 or Figs. 2, 4 and 5 of the

115 accompanying drawings.