Chainwheel, Drum Motor, Semi-Finished Chainwheel Product and Method for Producing a Chainwheel

Abstract

The invention relates to a chainwheel (1, 1′) for transferring a drive output from an input shaft, more particularly from a drum motor (800), onto a synthetic modular belt (900), a drum motor (800) for driving a synthetic modular belt, a semi-finished chainwheel product (10) for a chainwheel (1, 1′) and a method for producing a chainwheel (1, 1′). The chainwheel comprises at least one toothed ring and an outer ring (200, 200′) and an inner ring (300, 300′) adjoining the toothed ring, wherein the inner ring (300, 300′) and the outer ring (200, 200′) are connected to one another via bridges (410, 410′).

Claims

1. A sprocket (1, 1′) for transferring a drive power from a drive shaft, in particular from a drum motor (800), to a plastic modular belt (900), the sprocket (1, 1′) comprising at least one toothed ring (110) and an outer ring (200, 200′), which adjoins the toothed ring (110), and an inner ring (300, 300′), wherein the inner ring (300, 300′) and the outer ring (200, 200′) are connected to one another by means of webs (410, 410′).

2. The sprocket (1, 1′) as claimed in claim 1, characterized in that the sprocket (1, 1′) comprises at least two toothed rings, the teeth of which are preferably arranged offset relative to one another in a circumferential direction, and/or characterized in that the teeth of a toothed ring (110) or of both toothed rings (110, 120) are formed with tooth flanks of differing inclination, and/or characterized in that the outer ring (200, 200′) radially inwardly and/or directly adjoins the toothed ring or the toothed rings (110, 120), and/or the outer ring (200, 200′) bears the toothed ring or the toothed rings (110, 120).

3. The sprocket (1, 1′) as claimed in claim 1, characterized in that the inner ring (300, 300′) is spaced apart from the outer ring (200) in a radial direction or the outer ring (200, 200′) directly adjoins the inner ring (300, 300′), and/or characterized in that the outer ring (200, 200′) partially encloses the inner ring (300, 300′) in an axial direction, and/or characterized in that the outer ring (200, 200′) extends partially along the inner ring (300, 300′) in the radial direction, and/or characterized in that the webs (410, 410′) extend in the radial direction, in particular from the outer ring (200, 200′) to the inner ring (300, 300′), and/or characterized in that the webs directly adjoin the inner ring (300, 300′), preferably an end face of the inner ring (300, 300′), in the axial direction, and/or characterized in that the webs (410, 410′) are spaced apart from one another in the circumferential direction, and/or characterized in that individual, multiple or all webs extend over a total radial extent of the inner ring (300, 300′) in the radial direction, and/or characterized in that individual, multiple or all webs extend only over a part of the radial extent of the inner ring (300, 300′) in the radial direction, and/or characterized in that cavities (420) are formed between the webs (410, 410′), and/or characterized by an intermediate disk (430) which extends between the outer ring (200, 200′) and the inner ring (300, 300′) and preferably connects the outer ring (200, 200′) and the inner ring (300, 300′) and the webs (410, 410′) to one another.

4. The sprocket (1, 1′) as claimed in claim 1, characterized in that the inner ring (300, 300′) has a cutout for receiving a parallel key (820) which is preferably arranged on the drive shaft, and/or characterized in that the inner ring (300, 300′) has projections (340), in particular exactly three projections (340), for abutment against the drive shaft, wherein the projections (340) preferably protrude radially inward, and/or wherein the cutout for receiving the parallel key (820) is preferably arranged on one of the projections (340), and/or wherein the cutout and/or the projections (340) preferably extend over a total axial length of the inner ring (300, 300′).

5. The sprocket (1, 1′) as claimed in claim 1, characterized in that the inner ring (300, 300′) has an outer circumferential surface (350), wherein the outer circumferential surface (350) of the inner ring (300, 300′) preferably deviates from a cylindrical shape, and/or wherein the outer circumferential surface (350) of the inner ring (300, 300′) preferably has one or more projections (352) which are in particular spaced apart in the circumferential direction and/or one or more indentations (351) which are in particular spaced apart in the circumferential direction, and/or wherein the outer circumferential surface (350) of the inner ring (300, 300′) preferably has one or more steps (353) which are in particular spaced apart in the circumferential direction, and/or wherein the outer circumferential surface (350) of the inner ring (300, 300′) preferably has at least two or more portions which are in particular spaced apart in the circumferential direction and which have different radii, and/or characterized in that the outer ring (200, 200′) has, on its first end face, a first shoulder (210) which preferably projects beyond the first end face in the axial direction, and/or the outer ring (200, 200′) has, on its second end face, a second shoulder (220) which preferably projects beyond the second end face in the axial direction, and/or characterized in that a first end face of the inner ring (300, 300′) forms a first shoulder (310), and/or a second end face of the inner ring (300, 300′) forms a second shoulder (320).

6. The sprocket (1, 1′) as claimed in claim 1, wherein an axial extent from the first shoulder (210) to the second shoulder (220) of the outer ring (200, 200′) preferably corresponds to an axial extent from the first shoulder (310) to the second shoulder (320) of the inner ring (300, 300′), and/or wherein preferably an axial extent from the first shoulder (210) to the second shoulder (220) of the outer ring (200, 200′) is greater than an axial extent of the at least one toothed ring (110), preferably is greater than an axial extent of two toothed rings (110, 120), and/or an axial extent from the first shoulder (310) to the second shoulder (320) of the inner ring (300, 300′) is greater than an axial extent of the at least one toothed ring (110), preferably is greater than an axial extent of two toothed rings (110, 120), and/or wherein preferably an axial extent from the first shoulder (210) to the second shoulder (220) of the outer ring (200, 200′) is greater than an axial extent of the webs (410, 410′), and/or an axial extent from the first shoulder (310) to the second shoulder (320) of the inner ring (300, 300′) is greater than an axial extent of the webs (410, 410′), and/or wherein preferably an axial extent from the first shoulder (210) to the second shoulder (220) of the outer ring (200, 200′) is greater than an axial extent of the intermediate disk (430), and/or an axial extent from the first shoulder (310) to the second shoulder (320) of the inner ring (300, 300′) is greater than an axial extent of the intermediate disk (430), and/or an axial extent of the webs (410, 410′) is greater than an axial extent of the intermediate disk (430).

7. The sprocket (1, 1′) as claimed in claim 1, characterized by a first, in particular annular-disk-shaped, cover disk (510) which preferably extends from the first shoulder (210) of the outer ring (200, 200′) to the first shoulder (310) of the inner ring (300, 300′) and/or is preferably fastened to the first shoulder (210) of the outer ring (200, 200′) and/or the first shoulder (310) of the inner ring (300, 300′), in particular is fastened in a fluid-tight and/or materially bonded manner and/or by way of a welded connection, and/or characterized by a second, in particular annular-disk-shaped, cover disk (520) which preferably extends from the second shoulder (220) of the outer ring (200, 200′) to the second shoulder (320) of the inner ring (300, 300′) and/or is preferably fastened to the second shoulder (220) of the outer ring (200, 200′) and/or the second shoulder (320) of the inner ring (300, 300′), in particular is fastened in a fluid-tight and/or materially bonded manner and/or by way of a welded connection.

8. The sprocket (1, 1′) as claimed in claim 1, characterized in that the outer ring (200, 200′) is of circular form and/or the first shoulder (210) of the outer ring (200, 200′) is of circular form and/or the second shoulder (220) of the outer ring (200, 200′) is of circular form, and/or characterized in that an outer circumference of the first cover disk (510) is of circular form and/or an outer circumference of the second cover disk (520) is of circular form, and/or characterized in that an inner circumference of the first cover disk (510) has a cutout (330) for a parallel key (820) and/or an inner circumference of the first cover disk (510) has projections (340), in particular exactly three projections (340), for abutment against the drive shaft, wherein the projections (340) preferably protrude radially inward, and/or wherein the cutout (330) for receiving the parallel key (820) is preferably arranged on one of the projections (340), and/or an inner circumference of the second cover disk (520) has a cutout for a parallel key (820) and/or an inner circumference of the second cover disk (520) has projections (340), in particular exactly three projections (340), for abutment against the drive shaft, wherein the projections (340) preferably protrude radially inward, and/or wherein the cutout (330) for receiving the parallel key (820) is preferably arranged on one of the projections (340).

9. The sprocket (1, 1′) as claimed in claim 1, characterized in that the toothed ring or the toothed rings (110, 120) and/or the outer ring (200, 200′) and/or the inner ring (300, 300′) and/or the webs (410, 410′) and/or the intermediate disk (430) and/or the first cover disk (510) and/or the second cover disk (520) are composed of solid material, in particular plastic or metal, wherein the toothed ring or the toothed rings (110, 120) and/or the outer ring (200, 200′) and/or the webs (410, 410′) and/or the intermediate disk (430) and/or the first cover disk (510) and/or the second cover disk (520) are preferably composed of plastic and/or comprise plastic, and/or wherein the inner ring (300, 300′) is preferably composed of metal and/or comprises metal, and/or characterized in that the toothed ring or the toothed rings (110, 120) and/or the outer ring (200, 200′) and/or the inner ring (300, 300′) and/or the webs (410, 410′) and/or the intermediate disk (430) and/or the first cover disk (510) and/or the second cover disk (520) are produced in an injection-molding process, wherein the toothed ring or the toothed rings (110, 120) and the outer ring (200, 200′) and the inner ring (300, 300′) and the webs (410, 410′) and the intermediate disk (430) are preferably produced in a single, common injection-molding step, and/or characterized in that the toothed ring or the toothed rings (110, 120) and/or the outer ring (200, 200′) and/or the webs (410, 410′) and/or the intermediate disk (430) and/or the first cover disk (510) and/or the second cover disk (520) are produced in an injection-molding process, wherein the toothed ring or the toothed rings (110, 120) and the outer ring (200, 200′) and the webs (410, 410′) are preferably produced in a single, common injection-molding step, and/or wherein the toothed ring or the toothed rings (110, 120) and the outer ring (200, 200′) and the webs (410, 410′) are preferably injection-molded onto the inner ring (300, 300′), and/or characterized in that the cavities (420) between the webs (410, 410′) are free from filling material.

10. A drum motor (800) for driving a plastic modular belt (900), characterized in that two, three or more sprockets (1, 1′) as claimed in claim 1 are arranged, preferably axially spaced apart from one another, on the drum motor (800), in particular on its lateral surface (810) which forms a drive shaft.

11. A semi-finished sprocket product (10) of a sprocket (1, 1′) as claimed in claim 1, characterized in that the semi-finished sprocket product has, proceeding from a center point (M), production webs (500), in particular exactly three production webs (500), which preferably connect an injection point corresponding in particular to the center point (M), and/or two or more injection points assigned in each case to one or more production webs, to the inner ring (300, 300′) and/or to the webs (410, 410′).

12. A method (1000) for producing a sprocket (1, 1′) as claimed in claim 1, the method comprising forming at least one toothed ring (110) and an outer ring (200, 200′), which adjoins the toothed ring, and an inner ring (300, 300′), wherein the inner ring (300, 300′) and the outer ring (200, 200′) are connected to one another by means of webs (410, 410′).

13. The method as claimed in claim 12, comprising forming a first, in particular annular-disk-shaped, cover disk (510) which preferably extends from the first shoulder (210) of the outer ring (200, 200′) to the first shoulder (310) of the inner ring (300, 300′), and/or fastening the first cover disk (510) to the first shoulder (210) of the outer ring (200, 200′) and/or the first shoulder (310) of the inner ring (300, 300′), in particular in a fluid-tight and/or materially bonded manner and/or by way of a welded connection, and/or forming a second, in particular annular-disk-shaped, cover disk (520) which preferably extends from the second shoulder (220) of the outer ring (200, 200′) to the second shoulder (320) of the inner ring (300, 300′), and/or fastening the second cover disk (520) to the second shoulder (220) of the outer ring (200, 200′) and/or the second shoulder (320) of the inner ring (300, 300′), in particular in a fluid-tight and/or materially bonded manner and/or by way of a welded connection.

14. The method as claimed in claim 12, characterized in that the toothed ring or the toothed rings (110, 120) and/or the outer ring (200, 200′) and/or the inner ring (300, 300′) and/or the webs (410, 410′) and/or the intermediate disk (430) and/or the first cover disk (510) and/or the second cover disk (520) are produced from solid material, in particular plastic or metal, wherein the toothed ring or the toothed rings (110, 120) and/or the outer ring (200, 200′) and/or the webs (410, 410′) and/or the intermediate disk (430) and/or the first cover disk (510) and/or the second cover disk (520) preferably are or have been produced from and/or with plastic, and/or wherein the inner ring (300, 300′) preferably is or has been produced from and/or with metal, and/or characterized in that the toothed ring or the toothed rings (110, 120) and/or the outer ring (200, 200′) and/or the inner ring (300, 300′) and/or the webs (410, 410′) and/or the intermediate disk (430) and/or the first cover disk (510) and/or the second cover disk (520) are produced in an injection-molding process, wherein the toothed ring or the toothed rings (110, 120) and the outer ring (200, 200′) and the inner ring (300, 300′) and the webs (410, 410′) and the intermediate disk (430) are preferably produced in a single, common injection-molding step, and/or characterized in that the toothed ring or the toothed rings (110, 120) and/or the outer ring (200, 200′) and/or the webs (410, 410′) and/or the intermediate disk (430) and/or the first cover disk (510) and/or the second cover disk (520) are or have been produced in an injection-molding process, wherein the toothed ring or the toothed rings (110, 120) and the outer ring (200, 200′) and the webs (410, 410′) preferably are or have been produced in a single, common injection-molding step, and/or wherein the toothed ring or the toothed rings (110, 120) and the outer ring (200, 200′) and the webs (410, 410′) preferably are or have been injection-molded onto the inner ring (300, 300′), and/or characterized in that a semi-finished sprocket product is initially produced which has, proceeding from a center point, production webs (500), in particular exactly three production webs (500), which preferably connect an injection point corresponding in particular to the center point, and/or two or more injection points assigned in each case to one or more production webs, to the inner ring (300, 300′) and/or the webs (410, 410′).

15. The method as claimed in claim 12, comprising removing the production webs (500).

16. The sprocket as claimed in claim 1, wherein the inner ring (300) is composed of metal, and wherein the toothed ring or the toothed rings (110, 120) are composed of plastic and/or comprise plastic.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0076] Preferred exemplary embodiments are described by way of example on the basis of the appended figures, in which:

[0077] FIG. 1A shows a three-dimensional view of an exemplary embodiment of a sprocket without a first cover disk;

[0078] FIG. 1B shows the first cover disk for the sprocket as per FIG. 1A;

[0079] FIG. 1C shows a semi-finished sprocket product for a sprocket as per FIG. 1A;

[0080] FIG. 2A shows a plan view of a further exemplary embodiment of a sprocket;

[0081] FIG. 2B shows a side view of the sprocket as per FIG. 2A;

[0082] FIG. 2C shows an enlarged illustration of detail X from FIG. 2A;

[0083] FIG. 2D shows an enlarged illustration of detail Y from FIG. 2A;

[0084] FIG. 3A shows a three-dimensional view of a further exemplary embodiment of a sprocket without a first cover disk;

[0085] FIG. 3B shows the sprocket as per FIG. 3A with a first cover disk;

[0086] FIG. 4 shows a three-dimensional illustration of the exemplary embodiment of a drum motor with a plurality of sprockets and a plastic modular belt;

[0087] FIG. 5 shows a schematic flow diagram of an exemplary embodiment of a method for producing a sprocket;

[0088] FIG. 6A shows a plan view of a further exemplary embodiment of a sprocket;

[0089] FIG. 6B shows a sectional illustration of the sprocket as per FIG. 6A;

[0090] FIG. 6C shows a side view of the sprocket as per FIG. 6A;

[0091] FIG. 6D shows a three-dimensional view of the sprocket as per FIG. 6A;

[0092] FIG. 6E shows an enlarged section of the sprocket as per FIG. 6A;

[0093] FIG. 7A shows a plan view of a further exemplary embodiment of a sprocket;

[0094] FIG. 7B shows a sectional illustration of the sprocket as per FIG. 7A;

[0095] FIG. 7C shows a side view of the sprocket as per FIG. 7A;

[0096] FIG. 7D shows a three-dimensional view of the sprocket as per FIG. 7A;

[0097] FIG. 7E shows an enlarged section of the sprocket as per FIG. 7A;

[0098] FIG. 8A shows a plan view of an exemplary embodiment of an inner ring for a sprocket as per FIG. 6A and/or 7A;

[0099] FIG. 8B shows a side view of the inner ring as per FIG. 8A;

[0100] FIG. 9A shows a plan view of a further exemplary embodiment of an inner ring for a sprocket; and

[0101] FIG. 9B shows a plan view of a further exemplary embodiment of an inner ring for a sprocket.

[0102] In the figures, identical or substantially functionally identical elements are denoted by the same reference designations. General descriptions relate as a rule to all embodiments insofar as differences are not explicitly specified.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0103] The sprockets illustrated in the figures differ in particular by the following configuration details. According to the sprocket of FIGS. 1A to C, the webs 410 have reinforcing points 411 in an approximately radially central manner. The sprocket 1 as per FIGS. 1A to C also does not have an intermediate disk. The sprocket 1 as per FIGS. 2A to D has not just one cutout 330 for receiving a parallel key 820 but three such cutouts 330 which are all arranged centrally in a projection 340 of the inner ring 300. FIGS. 6A to E and 7A to E illustrate further embodiments of sprockets 1′ in which the inner ring 300′ is composed of high-grade steel and has an outer ring 200′ with webs 410′ molded thereon. The inner ring 300′ is also illustrated separately in FIGS. 8A, B. FIGS. 9A, B likewise show inner rings 300′ made of high-grade steel with a slightly amended geometry for different diameters of sprockets 1′.

[0104] FIG. 4 shows a drum motor 800 having a lateral surface 810 which forms a drive shaft, and also having a parallel key 820. Arranged on the lateral surface 810 are five sprockets 1 by means of which the drive power is transferred from the drum motor 800 to a plastic modular belt 900 (which is indicated merely schematically in FIG. 4). The middle one of the five sprockets 1 is axially fixed to the parallel key 820 in both directions by fixing pins 821 (only one of the two fixing pins is visible in FIG. 4). The remaining four sprockets 1 are mounted in a floating manner in the axial direction.

[0105] FIGS. 1A to 3B show a sprocket 1 for transferring a drive power from a drive shaft, in particular from a drum motor 800, as illustrated for example in FIG. 4, to a plastic modular belt 900, which is also indicated schematically in FIG. 4.

[0106] The sprocket 1 comprises two toothed rings 110, 120 and an outer ring 200 which adjoins the toothed rings 110, 120. The outer ring 200 has, on its first end face, a first shoulder 210 which projects beyond the first end face in the axial direction. Equally, the outer ring has, on a second, opposite end face, a second shoulder 220 which also projects beyond the second end face in the axial direction. The outer ring 200 and its first and second shoulders 210, 220 are of circular form.

[0107] Provided so as to be spaced apart from the outer ring 200 in the radial direction is an inner ring 300 whose first end face forms a first shoulder 310 and whose opposite second end face forms a second shoulder 320.

[0108] The inner ring 300 and the outer ring 200 are connected to one another by means of webs 410. Cavities 420 that are free from filling material are formed between the webs 410.

[0109] The axial extent from the first shoulder 210 to the second shoulder 220 of the outer ring 200 corresponds to the axial extent from the first shoulder 310 to the second shoulder 320 of the inner ring 300. The axial extent from the first shoulder 210 to the second shoulder 220 of the outer ring 200 is greater than the axial extent of the two toothed rings 110, 120. Also, the axial extent from the first shoulder 310 to the second shoulder 320 of the inner ring 300 is likewise greater than the axial extent of the two toothed rings 110, 120.

[0110] A multiplicity of radially oriented webs 410, which are spaced apart from one another in a substantially equidistant manner and the axial extent of which is smaller than the axial extent from the first shoulder 210 to the second shoulder 220 of the outer ring 200 and smaller than the axial extent from the first shoulder 310 to the second shoulder 320 of the inner ring 300, are arranged between the outer ring 200 and the inner ring 300.

[0111] As can be seen in particular in FIG. 3A, an intermediate disk 430 which connects the outer ring 200, the inner ring 300 and the webs 410 to one another extends between the inner ring 300 and the outer ring 200 and between the webs 410. The outer ring 200, the inner ring 300, the webs 410 and the intermediate disk 430 are all designed in the form of thin-walled elements. The two toothed rings 110, 120 are also designed in the form of thin-walled elements.

[0112] In particular an element whose extent in one dimension is smaller than 5 mm, in particular has an extent in one dimension that is approximately 1 to 3 mm, may be referred to as thin-walled. In the case of the intermediate disk 430, the toothed rings 110, 120 and the outer ring 200 (without its shoulders 210, 220), this is preferably the extent in the axial direction. In the case of the inner ring 300 and the first shoulder 210 and the second shoulder 220 of the outer ring 200, this is preferably the extent in the radial direction. In the case of the webs 410, this is preferably the extent in the circumferential direction.

[0113] The inner ring 300 and the first cover disk 510 and the second cover disk 520 have exactly three projections 340 for abutment against the drive shaft. The three projections 340 protrude radially inward and extend over the entire axial length of the inner ring 300. In FIGS. 1A to C and 3A and B, one of these projections 340 has a cutout 330 at its center for receiving a parallel key 820 arranged on a drive shaft. In the case of the sprocket 1 as per FIGS. 2A to D, cutouts 330 for receiving such parallel keys are also arranged on the other two projections 340.

[0114] The first cover disk 510 and the second cover disk 520 are of annular-disk-like form and extend from the first shoulder 210 of the outer ring 200 to the first shoulder 310 of the inner ring 300 and, respectively, from the second shoulder 220 of the outer ring 200 to the second shoulder 320 of the inner ring 300.

[0115] The cover disks 510, 520 are connected to the corresponding shoulders of the outer ring 200 and inner ring 300 in a fluid-tight manner, in particular by way of a welded connection, in order to produce closed end faces of the sprocket 1, wherein a connection by means of ultrasonic welding is particularly preferred. The cavities between the webs 410 are thus sealed.

[0116] The outer circumference of the cover disks 510, 520 is of circular form and the inner circumference of the cover disks 510, 520 has, just like the inner ring 300, a cutout for a parallel key and also three projections for abutment against the drive shaft. The cover disks 510, 520 thus correspond substantially to the contours of the shoulders of the outer ring 200 and of the inner ring 300.

[0117] A semi-finished sprocket product 10 for a sprocket 1 as per FIG. 1A is illustrated in FIG. 1C. The semi-finished sprocket product 10 has, proceeding from a center point M, three production webs 500 which connect an injection point corresponding to the center point M to the inner ring 300. This has advantages in particular in the case of the method 1000 described below for producing a sprocket 1.

[0118] The method 1000 for producing a sprocket 1 comprises forming 1001 the two toothed rings 110, 120 and an outer ring 200, which adjoins the toothed rings, and an inner ring 300, and also the webs 410 which connect the inner ring 300 and outer ring 200 to one another, and preferably also an intermediate disk 430. In particular, it is preferable that plastics material is injected via an injection point lying at the center point M via the production webs 500 into the inner ring 300, said plastics material passing from there via the webs 410 and the intermediate disk 430 into the outer ring 200 and the toothed rings 110, 120. The semi-finished sprocket product 10 is produced in this way.

[0119] In a step 1002, the production webs 500 are removed again.

[0120] A first cover disk 510 is formed in a step 1003, and a second cover disk 520 is formed in a step 1004. In a step 1005, these cover disks are fastened to the corresponding shoulders of the outer ring 200 and of the inner ring 300 in a fluid-tight manner, in particular by way of a welded connection by means of ultrasonic welding.

[0121] As can be seen in particular in FIG. 2D, the cutout 330 is preferably arranged centrally on one of the projections 340 of the inner ring 300 and has a width B and a height H. The transition from the projection 340 to the remaining region, which is offset radially outwardly relative thereto, of the inner ring 300 is preferably curved with a first radius R4 and a second, larger radius R5. The center angles between a center of the cutout 330 and the end of the transition from the projection 340 to the remaining region of the inner ring 300 are denoted by β1 and β2 in FIG. 2D, which are preferably the same size.

[0122] In FIG. 2A, D2 denotes the inner diameter of the inner ring 300. D1 denotes the inner diameter of the projections 340 on the inner ring 300. This diameter D1 of the projections 340 is smaller than the diameter D2 of the rest of the regions of the inner ring 300. In particular, the diameter D1 of the projections 340 on the inner ring 300 has to be produced with a high accuracy of fit since the projections 340 are intended to abut against a drive shaft and must be mounted thereon in an exact manner.

[0123] Furthermore, proceeding from the center of the upper cutout 330 in FIG. 2A, the center angles with respect to the respective centers of the left-hand and right-hand cutouts 330 in FIG. 2A are illustrated by α1 and α2. It may for example be preferred that the angle α1 is greater than the angle α2, for example by 10°.

[0124] Furthermore, FIG. 2B illustrates the axis X of the sprocket 1, said axis preferably coinciding with a longitudinal axis of the drum motor 800 in the mounted state.

[0125] FIG. 2C illustrates a section of the toothed rings 110, 120 adjoining the outer ring 200. A tooth 111 of the first toothed ring 110 and a tooth 121 of the second toothed ring 120 can be seen. The two teeth 111, 121 each have a relatively steep flank, denoted by 113, 123, and a less steep flank 112, 122. The angle of inclination of the steeper flanks 113, 123 is denoted by γ1. The angle between the two tooth flanks 112, 113 is denoted by γ2. This angle γ2 is preferably greater than the angle γ1.

[0126] The geometry of the sprocket 1 described here having a thin-walled configuration overall combined with toothed rings 110, 120 and an outer ring 200 made of solid material advantageously allows such a sprocket 1 to be cost-effectively produced by the method 1000 described here in the injection-molding process. At the same time, this configuration of the sprocket 1 permits a very high accuracy of fit with only a very small amount of warpage, with the result that a configuration of the sprocket 1 consisting of plastic is possible. The fluid-tight fastening of the cover disks 510, 520 to the shoulders of the outer ring 200 and inner ring 300 of the sprocket 1 closes the cavities 420 between the webs 410 in a fluid-tight manner, and so no contaminants can be deposited. Together with the projections 340 on the inner ring 300, which permit particularly good cleaning even of the interspace between the rest of the regions of the inner ring 300 of the sprocket 1 and the lateral surface 810 of the drum motor 800, the formation of the teeth 111, 121 of the toothed rings 110, 120 from plastic when used with plastic modular belts 900 affords a considerably lower level of wear than conventional sprockets made of high-grade steel, which predestines the sprocket 1 described here, with further advantages, in particular for hygienic applications, such as for example in the food industry.

[0127] The sprocket 1′ as per FIGS. 6A to D comprises only one toothed ring 110 and an outer ring 200′ which adjoins the toothed ring 110. The teeth 111, 112 are formed with tooth flanks of differing inclination. The sprocket 1′ as per FIGS. 6A to D having only one toothed ring 110 is therefore also suitable for reversing operation.

[0128] The sprocket 1′ as per FIGS. 7A to D comprises two toothed rings 110, 120 and an outer ring 200′ which adjoins the toothed rings 110, 120. The teeth 111, 112 are arranged offset relative to one another in the circumferential direction.

[0129] Both sprockets 1′ have an inner ring 300′ formed from high-grade steel. The outer ring 200′ directly adjoins the inner ring 300′, and the webs 410′ axially adjoin the inner ring 300′, in particular the first end face thereof, from the outer ring 200′. The outer ring 200′ is preferably injection-molded together with the webs 410′ onto the inner ring 300′. The outer ring 200′ and the webs 410′ are preferably formed from plastic and produced in an injection-molding process.

[0130] Furthermore, the outer ring 200′ partially encloses the inner ring 300′, in particular the opposite end faces thereof, in the axial direction by means of the extensions 201′. The extensions 201′ may be of ring-like form or may be interrupted in the circumferential direction. As a result, the outer ring 200′ extends partially along the inner ring 300′, in particular the opposite end faces thereof, in the radial direction. The extensions 201′ may also have the shape of further webs which preferably extend only over a part of the radial extent of the inner ring 300′ in the radial direction. In this way, the inner ring 300′ is axially fixed relative to the outer ring 200′, in particular by a form fit.

[0131] The webs 410′ directly adjoin the inner ring 300′, in particular an end face of the inner ring 300′, in the axial direction, as a result of which a form fit, in the form of a butt-joint connection, is formed between the webs and the inner ring. Since the webs 410′ are also connected to the outer ring 200′, in particular to the extensions 201′, there is thus preferably a connection of the outer ring to the inner ring by means of the webs.

[0132] The webs 410′ are produced together with the outer ring 200′ in a single, common injection-molding step and thus formed in one piece with the outer ring 200′. The webs 410′ extend over a total radial extent of the inner ring 300′ in the radial direction. The webs 410′ taper in the radial direction from the outside inward.

[0133] The inner ring 300′ has an outer circumferential surface 350 which deviates from a cylindrical shape. The outer circumferential surface 350 of the inner ring 300′ has a plurality of projections 352 which are spaced apart in the circumferential direction and a plurality of indentations 351 which are spaced apart in the circumferential direction. Steps 353 which are spaced apart in the circumferential direction are formed between the projections 352 and indentations 351. The projections 352 and indentations 351 form a plurality of portions which are spaced apart in the circumferential direction and which have different radii. This non-cylindrical configuration of the outer circumferential surface 350 of the inner ring 300′ has the advantage of preventing or reducing a relative movement between the inner ring 300′ and the outer ring 200′ in the circumferential direction.

[0134] The formation of the inner ring 300′ from metal, preferably high-grade steel, has the advantage that an increased stability and/or an improved transmission of force from the drive shaft to the sprocket 1′ can be obtained. At the same time, in combination with the formation of the outer ring 200′, the toothed ring or the toothed rings 110, 120 and the webs 410′ from plastic, the above-described advantages in relation to the use with plastic modular belts are achieved.