DEVICE FOR CONNECTING A TOOTHING PART TO A SHAFT FOR CONJOINT ROTATION WITH THE LATTER, METHOD FOR PRODUCING SUCH A DEVICE, AND ANGULAR GEAR

Abstract

Device (1) for connecting a toothing part (3) to a shaft (5) for conjoint rotation with the latter, having a toothing part (3) with a circular bore, a shaft (5) which has: a cylindrical receiving portion (4) for receiving the toothing part (3), and a cylindrical recess (8) in the shaft (5), which cylindrical recess (8) extends at least substantially over the entire length of the receiving portion (4), and a press-in cylinder (10) which can be pressed into the recess (8) and which has an oversize in relation to the recess (8).

Claims

1. Device (1) for connecting a toothing part (3) to a shaft (5) for conjoint rotation with the latter, having a toothing part (3) with a circular bore, a shaft (5) which has: a cylindrical receiving portion (4) for receiving the toothing part (3), and a cylindrical recess (8) in the shaft (5), which cylindrical recess (8) extends at least substantially over the entire length of the receiving portion (4), and a press-in cylinder (10) which can be pressed into the recess (8) and which has an oversize in relation to the recess (8).

2. Device (1) according to claim 1, wherein the wall thickness of the shaft (5) in the region of the receiving portion (4) is less than 15% of the external diameter of the receiving portion (4).

3. Device (1) according to claim 1, wherein an interference fit is present between the external diameter of the receiving portion (4) and the internal diameter of the bore of the toothing part (3).

4. Device (1) according to claim 1, wherein the press-in cylinder (10) comprises a bolt, and wherein an interference fit is present between the internal diameter of the recess (8) in the shaft (5) and the external diameter of the bolt.

5. Device (1) according to claim 1, wherein a connection that is free of form-fit engagement at least in the circumferential direction is present between the toothing part (3) and the receiving portion (4) and/or the shaft (5).

6. Device (1) according to claim 1, wherein a connection that is free of form-fit engagement at least in the circumferential direction is present between the press-in cylinder and the recess (8) of the shaft (5).

7. Device (1) according to claim 1, wherein the wall thickness of the shaft (5) in the region of the receiving portion (4) is at most 3 mm.

8. Device (1) according to claim 1, wherein the wall thickness of the shaft (5) in the region of the receiving portion (4) is greater than 3% of the external diameter of the receiving portion.

9. Device (1) according to claim 1, wherein the press-in cylinder is produced as a roller body of a roller bearing.

10. Device (1) according to claim 1, wherein the toothing part (3) is a bevel gear.

11. Device (1) according to claim 1, wherein the recess (8) has a contact region (16) which extends at least substantially over the length of the receiving portion (4) and, at least at one side of the contact region (16), is rotated freely with a free rotation diameter (18) which is greater than the diameter of the press-in cylinder.

12. Method for producing a device (1) according to claim 1, in which the toothing part (3) is pushed onto the receiving portion of the shaft (5), and the press-in cylinder is pressed into the recess (8) of the shaft.

13. Method according to claim 12, wherein the toothing part (3) is pushed onto the receiving portion (4) by pressing.

14. Angular gear with a device according to claim 1, wherein a bevel gear is provided as toothing part.

15. Angular gear according to claim 14 with a second device according to claim 1, wherein a second bevel gear is provided as toothing part on a second shaft, and wherein the second bevel gear meshes with the first bevel gear.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Illustrative embodiments of the invention are explained in more detail below with reference to drawings, in which:

[0027] FIG. 1 shows a schematic sectional view of a typical embodiment of a device;

[0028] FIG. 2 shows a further sectional view through the embodiment of FIG. 1;

[0029] FIG. 3 shows a schematic sequence of a typical embodiment of a method;

[0030] FIG. 4 shows a state while carrying out the method of FIG. 3; and

[0031] FIG. 5 shows a further state while carrying out the method of FIG. 3.

DETAILED DESCRIPTION

[0032] Typical illustrative embodiments of the invention are described below, wherein the same reference signs are used for identical or similar parts and are not explained again in the context of each figure. The invention is not limited to the typical embodiments described below.

[0033] FIG. 1 shows a typical embodiment of a device 1 in a schematic longitudinal section. A toothing part 3, being a hub configured as a bevel gear in the illustrative embodiment shown and having a circular bore, has been pressed with an oversize of H6/p6 onto a receiving portion 4 of a shaft 5 with a slight pressing force. The oversize relates here to the internal diameter of the circular bore of the toothing part 3 in relation to the external diameter of the receiving portion 4.

[0034] Where reference is made herein to the internal diameter or the inner face of the toothing part, this generally means the internal diameter of the circular bore of the toothing part.

[0035] The receiving portion 4 or an inner face of the toothing part 3 has a high surface quality with a roughness depth of less than 1 m.

[0036] The receiving portion and the inner face of the toothing part preferably both have a roughness depth of less than 1 m. In typical embodiments, the receiving portion of the shaft has, for manufacturing reasons, a roughness depth of more than 1 m, for example at least 3 m or less than 10 m. A typical example can be a receiving portion of the shaft with a roughness depth of 4 m. Both of said surfaces, the receiving portion and the inner face of the toothing part, typically have no structures, or they are to be designated as entirely cylindrical.

[0037] Moreover, the receiving portion 4 and the inner face 6 have been cleaned prior to assembly. In this way, high friction values for torque transmission can be achieved.

[0038] In typical embodiments, an inner face of the toothing part or the receiving portion are cleaned prior to assembly. For this purpose, solvent-based or water-based cleaners are used as cleaning agents.

[0039] The shaft 5 has a recess 8 configured as a through-bore. A press-in cylinder 10 is pressed into the recess 8. In the illustrative embodiment, the press-in cylinder 10 is a roller body of a cylindrical roller bearing which, in relation to the recess 8, has an oversize of 0.001 times the diameter of the press-in cylinder 10. Before being pressed in, the press-in cylinder 10 is wetted with a preservative or with an oil or grease.

[0040] In typical embodiments, before the press-in cylinder is pressed in, the press-in cylinder or the inner face of the recess is wetted with an oil, a grease or with a preservative. Typical means for doing this are: the lubricating grease Tribol GR 100-1 PD or the anti-corrosion agent Branotect. In this way, the pressing-in force can be reduced. In further embodiments, the press-in cylinder is pressed in without prior treatment with an oil, such that one work step is omitted.

[0041] By using a roller body as press-in cylinder, a part is used which is available as a standard part with high strength, high surface quality and low diameter tolerance. In further embodiments, specially produced bolts are used as press-in cylinder.

[0042] Through the action of the pressed-in press-in cylinder 10 in the recess 8, a widening of the shaft 5 in the region of the recess 8 is achieved, such that a pressing effect in the joint between shaft 5 and toothing part 3 is heightened and the torque that can be transmitted is increased.

[0043] For illustrative purposes, FIG. 2 shows a schematic cross section through the embodiment of FIG. 1 at the level of the toothing part 3.

[0044] FIG. 3 shows the sequence of a typical method for producing the typical device as shown in FIG. 1 and FIG. 2. FIG. 4 and FIG. 5 show states of the device during the production and are explained in connection with FIG. 3, with reference also being made to the reference signs and the explanations for the corresponding parts of FIG. 1 and FIG. 2. In particular, the reference signs in FIG. 4 and FIG. 5 are not all explained again and, in order to make matters clearer, not all the reference signs are shown in the two figures.

[0045] The method commences in a block 100. In a block 110, the toothing part 3 and the shaft 5 are made available. This state is also shown schematically in a longitudinal section in FIG. 4.

[0046] In the block 120, the toothing part 3 is pushed onto the receiving portion 4 of the shaft 3. A relatively low force is needed for this, since the shaft 3 in the region of the receiving portion 4 has a small wall thickness and thus low stiffness; the shaft 3 therefore yields and thus, despite the oversize of the toothing part 3, allows easy pushing onto the shaft 5. Through the pressing of the toothing part 3 onto the thin-walled receiving portion 4 of the shaft 3, a large part of the oversize goes into a diameter reduction of the recess 8, such that the oversize is increased from the press-in cylinder to the recess 8 after the pressing-on.

[0047] The shaft 5 and the toothing part 3 are shown in the assembled state in the lower part of FIG. 5. Moreover, in FIG. 5, the press-in cylinder 10 made available for the block 130 is shown in the upper part of FIG. 5.

[0048] In the block 130, the press-in cylinder 10 is pressed into the recess 8 of the shaft 5. The pressing-in can be made easier by wetting with oil. It should be noted that only compressive stresses have to be transmitted between the press-in cylinder 10 and the shaft 5, not a torque. Therefore, no shear stresses have to be transmitted in the joint between press-in cylinder 10 and recess 8 of the shaft 5, such that low friction between press-in cylinder 10 and shaft 5 affordsd advantages during assembly but no disadvantages during operation.

[0049] The method concludes in block 140.

[0050] FIG. 4 reveals in particular a number of details that are not shown quite as clearly or at all in the other figures. These details are now explained below as typical features of illustrative embodiments, although not all embodiments need to have these features.

[0051] In typical embodiments, a chamfer for facilitated pressing-in of the press-in cylinder can be provided at the opening of the receiving portion of the shaft; see the chamfer 12 on the receiving portion 8 in FIG. 4. In typical embodiments, the press-in cylinder has a chamfer.

[0052] To make the toothing part easier to push on, the toothing part or the shaft can have a chamfer at the outer circumference. In the typical illustrative embodiment of FIG. 4, the toothing part 3 has a chamfer 14.

[0053] Moreover, a contact region 16, which has a greater diameter than at least one adjoining groove 18, is formed on the receiving portion 4 of the embodiment of FIG. 4. With respect to the end of the shaft 5 onto which the toothing part 3 is pushed, the groove 18 lies at the remote end of the receiving portion 4. In this way, the joint between the receiving portion 4 and thus the contact region 16 of the receiving portion 8, on the one hand, and the inner face of the circular bore of the toothing part 3 is exactly defined, such that concentric running properties can be improved still further.

[0054] Moreover, in typical embodiments, the effective length of the contact between the press-in cylinder 10 and the shaft 5 is defined by the fact that, inside the recess, a central region is defined which is adjoined by a free rotation diameter 22. The central region is thus defined between the chamfer 12 of the shaft 5 and the free rotation diameter 22 and has at least the width of the toothing part 3 or the width of the contact region 16 of the receiving portion 8. Thus, at each location where the circular bore of the toothing part 3 is subjected to pressure from the inside, support from inside is provided by the press-in cylinder 10.

[0055] In some embodiments, by limiting the central region by means of a free rotation diameter 22, the effect achieved is that pressing between press-in cylinder 10 and shaft 5 occurs substantially only in the region that is important for the torque transmission. In this way, unnecessary deformations or distorsions of the shaft 5 are avoided.

[0056] FIG. 4 shows a state before the toothing part 3 is pressed on, and FIG. 5 shows a state after the toothing part 3 has been pressed on and before the press-in cylinder 10 has been pressed in.