Motor-driven conveying roller comprising a cooling sleeve pressed into the drum tube

Abstract

A motor-driven conveyor roller for conveyor systems for conveying containers, pallets, and the like, includes a drum tube with a cavity formed therein and a longitudinal axis, a shaft which extends in the longitudinal axis and on which the drum tube is supported by at least one bearing, and an electric drive unit arranged in the cavity. The motor-driven conveyor includes a cooling sleeve which is fixed radially inwardly to the drum tube and at least partially radially surrounds the drive unit so that a radial air gap is formed between the drive unit and the cooling sleeve. The disclosure also relates to a manufacturing process for such a conveyor roller.

Claims

1. A motor-driven conveyor roller for conveyor systems comprising: a drum tube having a cavity formed therein and a longitudinal axis; a shaft disposed along the longitudinal axis and on which the drum tube is mounted by at least one bearing; an electric drive unit positioned in the cavity; and a cooling sleeve disposed on an inner durface of and fixed to the drum tube and which at least partially radially surrounds the electric drive unit so that a radial air gap is formed between the electric drive unit and the cooling sleeve.

2. The motor-driven conveyor roller according to claim 1, wherein the cooling sleeve is force-fitted to the drum tube.

3. The motor-driven conveyor roller according to claim 1, wherein the cooling sleeve is axially slotted.

4. The motor-driven conveyor roller according to claim 1, wherein the electric drive unit comprises an electric motor and the cooling sleeve extends in an axial direction substantially over the electric motor.

5. The motor-driven conveyor roller according to claim 1, wherein the electric drive unit comprises a gear and the cooling sleeve extends in an axial direction substantially over the gear.

6. The motor-driven conveyor roller according to claim 1, wherein the radial width of the radial air gap is substantially constant in an axial direction.

7. The motor-driven conveyor roller according to claim 1, wherein the radial air gap has a radial width in a range from 0.1 mm to 2.5 mm.

8. The motor-driven conveyor roller according to claim 7, wherein the radial air gap has a radial width of about 0.5 mm.

9. The motor-driven conveyor roller according to claim 1, wherein a radially inner surface of the cooling sleeve has a surface roughness of Rz 50 or less.

10. The motor-driven conveyor roller according to claim 9, wherein the radially inner surface of the cooling sleeve has a surface roughness of Rz 30 or less.

11. The motor-driven conveyor roller according to claim 1, wherein a radially inner surface of the cooling sleeve has a surface treatment for absorbing thermal radiation.

12. The motor-driven conveyor roller according to claim 11, wherein the surface treatment is selected from the group consisting of coating the radially inner surface of the cooling sleeve with dark pigments, anodizing the radially inner surface of the cooling sleeve, bronzing the radially inner surface of the cooling sleeves, and copper plating the radially inner surface of the cooling sleeve.

13. The motor-driven conveyor roller according to claim 12, wherein the surface treatment comprises coating the radially inner surface of the cooling sleeve with black matt pigments.

14. The motor-driven conveyor roller according to claim 1, wherein the cooling sleeve has a thermal conductivity of 100 W/mK or more.

15. The motor-driven conveyor roller according to claim 14, wherein the cooling sleeve has a thermal conductivity of 130 W/mK or more.

16. The motor-driven conveyor roller according to claim 1, wherein the cooling sleeve is formed of a material having a density of 3.5 kg/dm.sup.3 or less.

17. The motor-driven conveyor roller according to claim 16, wherein the cooling sleeve is formed of a material having a density of 2.9 kg/dm.sup.3 or less.

18. The motor-driven conveyor roller according to claim 1, wherein the cooling sleeve is formed of an aluminum material.

19. The motor-driven conveyor roller according to claim 1, further comprising: a coupling unit adapted to transmit a torque from the electric drive unit to an inner peripheral surface of the drum tube, the coupling unit comprising a coupling bushing having a drive input portion communicating with the electric drive unit and an outer peripheral drive output portion; wherein the coupling bushing is frictionally connected to the inner circumferential surface of the drum tube only at points for the transmission of torques.

20. A manufacturing method for a motor-driven conveyor roller having a drum tube with a cavity formed therein and a longitudinal axis, a shaft disposed along the longitudinal axis and on which the drum tube is mounted by at least one bearing, an electric drive unit positioned in the cavity, and a cooling sleeve fixed radially inwardly to the drum tube and which at least partially radially surrounds the electric drive unit so that a radial air gap is formed between the electric drive unit and the cooling sleeve, the method comprising the steps of: providing the drum tube; providing the cooling sleeve; pressing the cooling sleeve into the drum tube to fix the cooling sleeve inside the drum tube; and inserting the electric drive unit into the cooling sleeve so that the radial air gap is formed between the electric drive unit and the cooling sleeve.

21. The manufacturing method according to claim 20, wherein the cooling sleeve is pressed into the drum tube such that an axial slit of the cooling sleeve does not extend along an axial weld seam of the drum tube.

22. The manufacturing process according to claim 20, further comprising the steps of: providing a coupling unit having a drive input portion for communicating with the electric drive unit and having an outer peripheral drive output portion; and pressing the coupling unit into the drum tube, wherein the coupling unit is connected to the inner circumferential surface of the drum tube with frictional engagement only at points for the transmission of torques.

23. The manufacturing method according to claim 22, wherein the pressing in step of the coupling unit and the pressing in step of the cooling sleeve are carried out as a single step.

24. A manufacturing process for a motor-driven conveyor roller comprising a drum tube with a cavity formed therein and a longitudinal axis, a shaft disposed along the longitudinal axis and on which the drum tube is mounted by at least one bearing, an electric drive unit positioned in the cavity, and a cooling sleeve fixed radially inwardly to the drum tube and which at least partially radially surrounds the electric drive unit so that a radial air gap is formed between the electric drive unit and the cooling sleeve, the method comprising the steps of: selecting the drum tube from a plurality of drum tubes having a predetermined diameter, wherein the plurality of drum tubes comprises at least one drum tube having an outer diameter of 50 mm and at least one drum tube having an outer diameter of 60 mm; and selecting the cooling sleeve from a plurality of cooling sleeves, wherein the plurality of cooling sleeves comprises at least one cooling sleeve which is provided for the at least one drum tube having an outer diameter of 50 mm and at least one cooling sleeve which is provided for the least one drum tube having an outer diameter of 60 mm; the selection of the cooling sleeve being carried out such that, after insertion of the electric drive unit into the cooling sleeve, the radial air gap has a radial width in a range from 0.1 mm to 2.5 mm.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Further advantages, features, and details of the invention can be found in the following description of the preferred embodiments as well as in the drawings; these show in:

(2) FIG. 1 is a full section through a motor-driven conveyor roller according to a first embodiment;

(3) FIG. 2 is a full section through a motor-driven conveyor roller according to a second embodiment;

(4) FIG. 3 is a side view of a cooling sleeve;

(5) FIG. 4 is a frontal view of the cooling sleeve from FIG. 3;

(6) FIG. 5 is a frontal view of a cooling sleeve with a surface-treated inner surface; and

(7) FIG. 6 is perspective view of a coupling unit with a coupling bushing.

DETAILED DESCRIPTION OF THE EMBODIMENTS

(8) A motor-driven conveyor roller 1 has a drum tube 2, which has a central axis A. The drum tube 2 can be rotated around the central axis A. For this purpose, the conveyor roller has a shaft 4 which, with reference to FIG. 1, extends out of the drum tube 2 on the right and can be mounted in a frame for a conveyor system. No shaft is shown on the left-hand side of drum tube 2 with reference to FIG. 1; the conveyor roller is rather partially broken out here. In normal operation, an additional shaft would be provided on the left-hand side with reference to FIG. 1, which is omitted in the illustration shown in FIG. 1 for the sake of clarity.

(9) A rotational bearing 6 is mounted on the shaft 4, which carries a cover 8 that is pressed into the right-hand end of the drum tube 2 with respect to FIG. 1.

(10) The shaft 4 has a central hole 10, through which a supply cable 12 runs. The supply cable 12 runs to a drive unit 14, which has an electric motor 16 and a gear 18, which is designed as a gear cartridge. A coupling unit 22 is provided on the drive output side 20 of gear unit 18, which will be described in more detail later with reference to FIG. 6. This coupling unit 22 serves to transmit the torque supplied by the electric motor 16 via a force-fit (frictional) connection 24 to the drum tube 2 in order to set the drum tube 2 in rotation.

(11) The drive unit 14 has a housing 26, which is essentially rotationally symmetrical. The housing 26 has a diameter D1, which, for example, can be 40 mm. For example, an inner diameter D2 of the drum tube is 48 mm, if the drum tube has an outer diameter of 50 mm. It should be understood that these values are only exemplary and that other values are also possible and preferred. The exact values depend in particular on the type of drive unit 14 as well as on the wall thickness of drum tube 2 and the outer diameter of drum tube 2.

(12) According to the invention, a cooling sleeve 30 is provided to cool the drive unit 14, which at least partially radially surrounds the drive unit 14 and is attached to the drum tube 2. More precisely, the cooling sleeve 30 is pressed into the drum tube 2 and lies flat against the inner circumferential surface 32 of drum tube 2. According to this embodiment (FIG. 1), the cooling sleeve 30 extends in the axial direction from cover 8, or just in front of cover 8, to at least part of the gear unit 18 and thus radially encloses all elements of the conveyor roller 1 that emit heat.

(13) The drive unit 14 is connected to the shaft 4 in a non-rotating manner and is supported against the shaft 4. The housing 26 of the drive unit 14 also does not rotate. To allow rotation of the drum tube 2 together with the cooling sleeve 30, an air gap S is provided between the drive unit 14 and the cooling sleeve 30. In this embodiment (FIG. 1), the air gap S has a radial width S1 in the area of housing 26 and a radial width S2 in the area of gear unit 18, which is not covered by housing 26. The inner surface 34 of the cooling sleeve 30 is flat and does not have any steps or the like. Therefore, the radial width S2 in the area of the gear 18 is slightly larger than the radial width S1 in the area of the housing 26, while the radial width S1 is about 0.5 mm, the radial width S2 is about 2 mm.

(14) FIG. 2 shows a second embodiment of the motorized conveyor roller 1. In this second embodiment, identical and similar elements are marked with the same reference signs as in the first embodiment (FIG. 1), so that full reference is made to the above description of the first embodiment. In the following, the differences to the first embodiment are particularly highlighted.

(15) In contrast to the first embodiment, drive unit 14 has only two gear stages, so that the cooling sleeve 30 extends completely axially over electric motor 16 and gear 18. Furthermore, the cooling sleeve 30 has a section 36 which is separated by a circumferential step 38. The section 36 has a slightly reduced inner diameter, so that the cooling sleeve 30 in this section 36 is adapted to the reduced outer diameter D3 of the gear unit 18. In this way the air gap S is uniform and the radial width S1 is provided both in the area of the housing 26 and in the area of the gear unit 18. An expansion of the air gap S as in the first embodiment (FIG. 1) is not provided in this embodiment (FIG. 2).

(16) The cooling sleeve 30 itself is shown in detail with reference to FIGS. 3 to 5. The cooling sleeve 30 shown in FIG. 3 is the cooling sleeve 30 of the first embodiment (FIG. 1). The cooling sleeve 30 has an essentially cylindrical shape and is manufactured in one piece, for example by computer numerical control (CNC) turning, CNC milling, extrusion, and/or rolling, in particular, cold rolling. The cooling sleeve 30 has an outer diameter D4 which is slightly larger than the inner diameter D2 of the barrel tube 2 to allow for an interference fit.

(17) In order to enable the mounting of the cooling sleeve 30, it is axially slotted and has a slot 42. The slot has a width G, which can be in the range of 4 mm, for example. The width G depends on the wall thickness W of the cooling sleeve 30 as well as on the difference between the outer diameter D4 and the inner diameter D2 and also on the material of the cooling sleeve 30. The width G of the slot 42 should be dimensioned in such a way that it is possible to insert the cooling sleeve 30 into the inside of the barrel tube 2, even taking maximum tolerances into account.

(18) In order to further simplify the assembly process, the cooling sleeve 30 has mounting chamfers 44, 44a on both sides, each ending in a shoulder 46, 46a with a diameter D5. The diameter D5 is smaller than the diameter D4, for example about 4-6% smaller. The diameter D5 should be dimensioned so that it is also slightly smaller than the diameter D2, so that the cooling sleeve 30 can initially be inserted into the inside of the drum tube 2 with the shoulder 46 without any problems and without applying a large force during assembly, before radial compression of the cooling sleeve 30 takes place, in order to then move it completely into the inside of the drum tube 2.

(19) The inclination of chamfer 44, for example, can be in the range of 60° to the central axis A.

(20) Due to the chamfers 44, 44a on both sides, the cooling sleeve can be pressed in each of the two conceivable orientations, so that incorrect assembly is impossible and an alignment step of the cooling sleeve to press in a defined side of the cooling sleeve in front can be omitted in an automated assembly.

(21) Both the inner surface 34 and the outer surface 40 of the cooling sleeve 30 have a surface roughness of preferably Rz 30 or less, preferably Rz 25 or less. This means that both surfaces 34, 40 are preferably finished. The outer surface 40 should be formed in such a way that a frictional connection with the inner circumferential surface 32 of the drum tube 2 is as secure as possible and, at the same time, the contact area should be as large as possible in order to allow heat conduction from the cooling sleeve 30 to the drum tube 2.

(22) The inner surface 34 should be formed in such a way that it does not reflect, but allows the most efficient heat radiation from the drive unit 14 to the cooling sleeve 30.

(23) For this purpose, it may be provided that the cooling sleeve 30 has a surface treatment 48 on its inner surface 34, for example, a bronzing, anodizing, or a coloured layer, in particular, with a dark colour, particularly black, in order to absorb thermal radiation as well as possible and reflect little thermal radiation.

(24) In total, the cooling sleeve 30 is preferably made of a light metal. Aluminium is particularly useful here. Aluminium should be used which has a density of preferably 3 kg/dm3 or less and a thermal conductivity of preferably 130 W/mK or more. Suitable alloying metals can be added to the aluminium for this purpose.

(25) FIG. 6 shows a part of coupling unit 22, which has already been shown in section in FIGS. 1 and 2. The coupling unit 22 acts exclusively frictionally and is preferably mounted together with the cooling sleeve 30. This coupling unit 22 is described in the German patent application DE 10 2016 124 689 of the local applicant, whose disclosure content is fully included in this application.

(26) The coupling unit 22 has a coupling bushing 50, in whose central opening 74 a toothed shaft piece 51 can engage. The toothed shaft piece 51 is connected to the output of the gear unit 18.

(27) The coupling bushing 50 has a two-part design and has a radially inner part 62 and a radially outer part 60. The radially outer part 60 forms an output section 52, which is frictionally connected to the inner circumferential surface 32 of the drum tube 2.

(28) The inner part 62 has a substantially cylindrical circumferential surface 92, to which the outer part 60 is applied in the form of a corrugated metal strip. The corrugated metal strip of the outer part 60 forms a plurality of lugs 54, which are hollow in this design and define a cavity 94 inside. This provides the elasticity of the lugs 54, and manufacturing tolerances can be compensated.

(29) The inner part 62 has projections 78, in which axial recesses 82 are provided. These axial recesses 82 serve on the one hand to reduce weight and on the other hand to make the projections 78 elastic in order to allow torque transmission from the splined shaft piece 51 to the inner part 62 elastically.

(30) The corrugated sheet metal strip, which forms the outer part 60, interacts frictionally with both the inner circumferential surface 32 and the outer surface 92 of the inner part 62. Due to the flexibility of the sheet metal strip, tolerances can be compensated and a permanent frictional connection is provided. It is conceivable that the coupling bushing 50 is pushed into the inside of the drum tube 2 by means of the cooling sleeve 30. This saves one additional assembly tool for mounting the coupling bushing 50, as the coupling bushing 50 is mounted in one step with the cooling sleeve 30.