Transmission wheel and a method for its mounting

Abstract

A transmission wheel assembled of at least two segments (1) on a shaft (12), the inner arc surface (3) of which and the shaft (12) have essentially the same radius (R), and which segments' (1) outer surfaces (9) have profiled surfaces that transmit the power of the transmission wheel. Between the segments' (1) welded-together end faces (4) there are gaps on those sections of the end faces (4) that are not welded, which creates a press fit between the shaft (12) and the inner arc surface (3) of the transmission wheel. The weld connecting the transmission wheel segments' (1) end faces (4) may be incomplete, meaning that it does not reach the shaft (12).

Claims

1. A transmission wheel comprising: at least two segments on a shaft, wherein an inner arc surface of each of the at least two segments and the shaft have the same radii and the at least two segments includes a first segment and a second segment, and outer surfaces of the at least two segments include profiled surfaces configured to transmit power of the transmission wheel, end faces on each of the at least two segments, wherein a first end face of the end faces is on the first segment faces a second end face of the end faces is on the second segment, and a weld connecting the first end face and the second end face, wherein a first section of the first end face faces a second section of the second end face; wherein the first section and the second section are not welded, and wherein a gap is between the first section of and second section.

2. The transmission wheel according to claim 1, wherein the weld connecting the first end face and the second end face does not extend to the shaft.

3. The transmission wheel according to claim 1, wherein an inner edge region of at least one of the first end face and the second end face includes a notch.

4. The transmission wheel according to claim 1, wherein an inner edge region of at least one of the first end face and the second end face includes a shoulder within a notch.

5. A transmission wheel comprising: arc-shaped segments assembled on a shaft, wherein an inner arc surface of each of the arc-shaped segments is seated on an outer surface of the shaft; outer surfaces of each of the arc-shaped segments include profiled surfaces configured to transmit power of the transmission wheel, end faces on opposite ends of each of the arc-shaped segments, wherein the end faces include a first end face on a first of the arc-shaped segments and a second end face on a second of the arc-shaped segments, and the first end face faces the second end face; a weld connecting the first end face and the second end face, and a first section of the first end face faces a second section of the second end face, wherein the first section and the second section are separated by a gap and are not welded.

6. The transmission wheel of claim 5 wherein the weld is spaced apart from the shaft.

7. The transmission wheel of claim 5, wherein at least one of the end faces on each of the arc-shaped segments includes an inner edge region adjacent the shaft, and the inner edge region includes a notch.

8. The transmission wheel according to claim 7, wherein the inner edge region of each of the arc-shaped segments includes a shoulder within the notch.

9. A method for mounting a transmission wheel on a shaft with a press fit, the method includes: arranging transmission wheel segments in an annular array on the shaft, wherein gaps are each between opposing pairs of end faces of the transmission wheel segments and the gaps collectively are at least 0.2 mm during the arranging step, wherein an outermost edge and/or side of the edges of each of the end faces are beveled such that a welding groove is formed between each of the pairs of the opposing end faces, tightening tools are placed on outer surfaces of two of the transmission wheel segments and the tightening tools are applied to push together the opposing end faces, welding the transmission wheel segments together by forming welds in the welding grooves, wherein the welding step leaves the gaps between each of the pairs of the opposing end faces and the gaps are each at a section of each of the pairs of opposing end faces between the weld and the shaft, and removal of the tightening tools after the welding.

10. The method of claim 9, wherein the step of welding shrinks the gaps.

Description

BRIEF DESCRIPTION OF THE FIGURES

(1) The invention is described more closely in the context of preferable embodiments with reference to the figures provided, where

(2) FIG. 1 presents a side view of two transmission wheel segments according to the preferable embodiment placed against each other, and

(3) FIG. 2 presents a transmission wheel segment to be welded at the sides.

DETAILED DESCRIPTION OF THE INVENTION

(4) FIG. 1 presents a side view of two transmission wheel segments 1 according to the preferable embodiment placed against each other such that their inner surfaces 3 sit on a shaft 12 with substantially the same radius. The outer surfaces 9 of the transmission wheel segments 1 have profiled surfaces aligned with the shaft for power transmission purposes. The ends of the transmission wheel segments 1 have end faces 4, the outer surfaces of which preferably have bevels 5 that form between them a welding groove. The bevel 5 could be shaped like, for example, the letter J in order to form a U groove.

(5) In order to ensure that the shrinkage caused by welding creates a strong press fit, the end faces 4 must not touch each other even after welding. For this reason, the transmission wheel segments must be incomplete enough compared to a full sector according to the segment division, and a gap with the width X must be left between the end faces 4, in which case the width of the aforementioned incompleteness is X/2. In case of two transmission wheel segment halves, the width of the incompleteness X/2 is the inner arc surface's 3 radius R minus measurement Y from the level of the end faces 4 to the highest point 10 of the inner arc surface 3 of the transmission wheel segment 1. The segments 1 are placed on the shaft 12 such that the gap width X is sufficient in each gap between the end_faces 4.

(6) Preferably, the inner corners of the end faces 4 have either a shoulder 6 or a corresponding notch 7. The shoulder 6 should be longer than the width of the gap X left between the end faces 4, and the corresponding notch 7 should be deep enough that the shoulder 6 does not reach its end face and prevent the weld 13 from shrinking and a press fit from forming on the shaft. The thickness of the shoulder 6 must not exceed the depth of the notch 7 so that the side faces of the shoulder 6 and notch 7 do not cause friction and hinder mounting. The shoulder 6 can be thick enough to also serve as a backing strip. The joining of the end face can also be done such that the end faces 4 have only notches 7 on at least one side of the joint. In that case, the notch is not filled by a shoulder 6. The end faces 4 can then be welded together by their other surfaces, at least for the most part. The notch 7 ensures a sufficient gap between the end faces 4 at the notch 7. In that case, even minor incompleteness of the weld on the end faces 4 will not necessarily hinder weld shrinking because the narrow incomplete area will heat during welding, making it easily deforming, and thus will not materially hinder the shrinkage.

(7) The joining of the end face can also be done such that the end faces 4 have only notches 7 on at least one side of the joint. In that case, the notch is not filled by a shoulder 6. The end faces 4 can then be welded together by their other surfaces, at least for the most part. The notch 7 ensures a sufficient gap between the end faces 4 at the notch 7. In that case, even minor incompleteness of the weld on the end faces 4 will not necessarily hinder weld shrinking because the narrow incomplete area will heat during welding, making it easily deforming, and thus will not materially hinder the shrinkage.

(8) Before the welding phase, both sides of the transmission wheel segment 1 joints will be fitted with tightening tools 11, which will be used to tighten the transmission wheel segments 1 to the shaft without play, for example with bolts or separate clamps. The tightening has no significant impact on the frictional force of the press fit, if the segment sits on the shaft without play. Otherwise, the frictional force is left smaller than planned when the gap is not removed until due to the shrinkage caused by the welding.

(9) FIG. 2 presents a transmission wheel segment in accordance with a preferable embodiment where the outer surface 9 has a transverse profiled surface in regard to the shaft 12. The transmission wheel segment end faces 4 have bevels 8 on both side edges, serving as surfaces of the welding groove.