INTERFERENCE FIT CONNECTION FOR A SHAFT

Abstract

An interference fit connection for a shaft comprises a hub having a conical through opening and a reduction sleeve having a cylindrical through opening for arrangement on the shaft and a conical outer circumference, where the cone angle of the conical outer circumference corresponds to the cone angle of the corresponding conical through opening of the hub. The hub is a two-component part having a first component made of steel and a second component made of fiber-reinforced plastics material. The second component made of fiber-reinforced plastics material is designed as a ring which is arranged on the outer circumference of a sleeve portion of the first component, which sleeve portion surrounds the reduction sleeve, so as to surround this sleeve portion. The fiber-reinforced plastics material has a higher modulus of elasticity than the steel of the first component.

Claims

1. An interference fit connection for a shaft (10), comprising: a hub (1) having a conical through opening (5), and a reduction sleeve (6) having a cylindrical through opening (7) for arrangement on the shaft (10) and a conical outer circumference (8), the cone angle of the conical outer circumference (8) corresponding to the cone angle of the corresponding conical through opening (5) of the hub (1), wherein the hub (1) is a two-component part having a first component made of steel and a second component made of fiber-reinforced plastics material, the second component made of fiber-reinforced plastics material is designed as a ring (9) which is arranged on the outer circumference of a sleeve portion (2) of the first component, which sleeve portion surrounds the reduction sleeve, so as to surround this sleeve portion (2), the fiber-reinforced plastics material having a higher modulus of elasticity than the steel of the first component.

2. The interference fit connection according to claim 1, wherein the hub (1) has said sleeve portion (2), which is elongate, and a flange portion (3) which protrudes radially from the sleeve portion (2) and is provided with attachment structures for coupling to a further component.

3. The interference fit connection according to claim 1, wherein the sleeve portion (2) has a radially gradated region (2a) reduced in diameter to for a step and the ring (9) made of fiber-reinforced plastics material is arranged in the gradated region (2a).

4. The interference fit connection according to claim 3, wherein the radial wall thickness (t) of the ring (9) made of fiber-reinforced plastics material corresponds to the height (h) of the step of the gradated region (2a).

5. The interference fit connection according to claim 1, wherein that the ratio of the wall thickness (t) of the ring (9) made of fiber-reinforced plastics material to the wall thickness (s) of the underlying sleeve portion (2) of the first component is 0.5 to 2.

6. The interference fit connection according to claim 1, wherein, the second component comprises a primary material, wherein the primary material is directly applied to the steel of the first component and cured there.

7. The interference fit connection according to claim 6, wherein the ring (9) is made from prepregs.

8. The interference fit connection according to claim 1, wherein the second component comprises a primary material, wherein the primary material is directly applied to the steel of the first component and cured there, and wherein the ring (9) is individually wound and resin added for curing.

9. The interference fit connection according to claim 1, wherein the fibers of the fiber composite material in the ring (9) are wound in the circumferential direction thereof.

10. The interference fit connection according to claim 1, wherein the ring (9) is made from unidirectional layers applied in such a way that, in the circumferential direction, the fibers thereof are positioned around the reduction sleeve (6) and around the gradated region (2a) of the sleeve portion (2).

11. The interference fit connection according to claim 1, wherein the fibers of the fiber composite material in the ring (9) are high-modulus carbon fibers.

12. The interference fit connection according to claim 11, wherein the fibers of the fiber composite material in the ring (9) have a modulus of elasticity greater than 370 GPa.

13. The interference fit connection according to claim 1, wherein the conical outer circumference (8) of the reduction sleeve (6) has a hardened surface quality comprising an average roughness Ra in the range of from 1.5 to 15 μm.

14. The interference fit connection according to claim 13, wherein the inner circumference of the cylindrical through opening (7) of the reduction sleeve (6) has a hardened surface quality comprising an average roughness Ra in the range of from 1.5 to 15 μm for radial contact against the shaft.

15. The interference fit connection according to claim 1, wherein a chamber (12) is formed between the hub (1) and the reduction sleeve (6), a closure plug (11) is attached to the reduction sleeve (6), which plug axially closes said chamber (12) formed between the hub (1) and the reduction sleeve (6) and wherein at least one hydraulic connection (13) is provided on the hub (1) in order to apply a hydraulic medium to the chamber (12) for pressing the hub (1) onto the reduction sleeve (6).

16. An interference fit connection for a shaft (10), comprising a hub (1) having an elongate sleeve portion (2), a flange portion (3) which protrudes radially from the sleeve portion (2) and is provided with attachment structures for coupling to a further component, and a conical through opening (5); a reduction sleeve (6) having a cylindrical through opening (7) for arrangement on the shaft (10) and a conical outer circumference (8), the cone angle of the conical outer circumference (8) corresponding to the cone angle of the corresponding conical through opening (5) of the hub (1), wherein the hub (1) is a two-component part having a first component made of steel and a second component made of fiber-reinforced plastics material, the fiber-reinforced plastics material having a higher modulus of elasticity than the steel of the first component; wherein the second component made of fiber-reinforced plastics material is designed as a ring (9) which is arranged on the outer circumference of a sleeve portion (2) of the first component, which sleeve portion surrounds the reduction sleeve, so as to surround this sleeve portion (2), and wherein sleeve portion (2) has a radially gradated region (2a) reduced in diameter to form a step and the ring (9) made of fiber-reinforced plastics material is arranged in the gradated region (2a).

17. The interference fit connection according to claim 16, wherein the second component comprises a primary material, wherein the primary material is directly applied to the steel of the first component and cured there.

18. The interference fit connection according to claim 17, wherein the ring (9) is made from prepregs.

19. The interference fit connection according to claim 16, wherein the second component comprises a primary material, wherein the primary material is directly applied to the steel of the first component and cured there, and wherein the fibers of the fiber composite material in the ring (9) are wound in the circumferential direction thereof and resin is added for curing.

20. An interference fit connection for a shaft (10), comprising a hub (1) having a conical through opening (5); and a reduction sleeve (6) having a cylindrical through opening (7) for arrangement on the shaft (10) and a conical outer circumference (8), the cone angle of the conical outer circumference (8) corresponding to the cone angle of the corresponding conical through opening (5) of the hub (1); wherein the hub (1) is a two-component part having a first component made of steel and a second component made of fiber-reinforced plastics material, the fiber-reinforced plastics material having a higher modulus of elasticity than the steel of the first component; wherein the second component made of fiber-reinforced plastics material is designed as a ring (9) which is arranged on the outer circumference of a sleeve portion (2) of the first component, which sleeve portion surrounds the reduction sleeve, so as to surround this sleeve portion (2); and wherein the second component comprises a primary material, wherein the primary material is directly applied to the steel of the first component and cured there, the ring (9) being made from one selected from prepregs, fibers wound in the circumferential direction of the ring (9).

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0032] The invention will be explained in more detail below with reference to an embodiment shown in the drawing, in which:

[0033] FIG. 1 is a longitudinal sectional view of an embodiment for an interference fit connection according to the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0034] The interference fit connection shown in FIG. 1 is used, for example, to attach a flange 1, also referred to below as a hub 1, to a shaft 10. The shaft 10 can be designed as a solid or hollow shaft. It is preferably made of steel. The flange 1 can be connected, for example, to a corresponding flange of a shaft made of fiber composite material.

[0035] The interference fit connection explained in more detail below can, however, also be used for other purposes, in particular those in which a low weight is of great interest.

[0036] The interference fit connection initially comprises the hub 1 which has already been mentioned. This hub 1 has an elongate sleeve portion 2 and a flange portion 3 which protrudes radially therefrom. Attachment structures such as through openings 4 for coupling to a further component can be provided on the flange. A conical through opening 5 extends through the hub 1.

[0037] Furthermore, the interference fit connection comprises a reduction sleeve 6, which is located between the hub 1 and the shaft 10 in the installed state.

[0038] The reduction sleeve 6 has a cylindrical through opening 7 for arrangement on the shaft 10 and also a conical outer circumference 8 for engagement with the conical through opening 5 of the hub 1.

[0039] The cone angle of the conical outer circumference 8 of the reduction sleeve 6 corresponds to the cone angle of the conical through opening 5 of the hub 1.

[0040] In the present case, the hub 1 is designed as a two-component part comprising a first component made of steel and a second component made of fiber-reinforced plastics material.

[0041] Here, the second component made of fiber-reinforced plastics material is designed as a ring 9 which is arranged on the outer circumference of the sleeve portion 2 of the first component. The ring 9 is integrally fitted on the outer circumference of the sleeve portion 2 of the first component and surrounds said outer circumference. As a result, the first component is reinforced in the region of receiving the reduction sleeve 6. For this purpose, the fiber-reinforced plastics material has a higher modulus of elasticity than the steel of the first component.

[0042] In the illustrated embodiment, the sleeve portion 2 forms a radially gradated region 2a, while the ring 9 made of fiber-reinforced plastics material is arranged in the gradated region 2a.

[0043] In the simplest case, the ring 9 is designed in the manner of a cylindrical sleeve. The radial wall thickness t of the ring 9 made of fiber-reinforced plastics material can correspond to the height h of the step of the steplike gradated region 2a of the sleeve portion 2, which ideally results in a smooth transition in the region of the sleeve portion 2 between the steel and fiber composite components. However, an edge can also be permitted at this point.

[0044] The ratio of the wall thickness t of the ring 9 made of fiber-reinforced plastics material to the wall thickness s of the underlying sleeve portion is preferably in the range of from 0.5 to 2.

[0045] The ring 9 can be manufactured and attached to the first component in different ways. It is thus possible to first manufacture said ring as a component made of fiber-reinforced plastics material and then to assemble the finished ring 9 on the steel component. Thermal joining processes, for example, can be used for this purpose. It is also possible to apply the primary material for the ring 9 directly to the steel component and to cure it there.

[0046] Prepregs can be used to manufacture the ring. However, a more flexible choice of material allows the ring to be individually wound and the resin desired in each case to be added for curing.

[0047] When using prepregs, the fibers can be in the form of woven fabrics or non-woven fabrics. However, unidirectional layers are preferably used in such a way that, in the circumferential direction, the fibers are positioned around the reduction sleeve 6 and around the gradated region 2a of the sleeve portion 2.

[0048] In the case of winding the fibers, they are wound in the circumferential direction of the ring 9, i.e. also wound around the reduction sleeve 6 and the gradated region 2a of the sleeve portion 2.

[0049] The fibers of the fiber composite material have a modulus of elasticity greater than 370 GPa.

[0050] High-modulus carbon fibers are preferably used on the ring 9.

[0051] In order to increase the coefficients of friction in the interference fit and thus to increase the torque transmission capacity, measures to increase friction can preferably be carried out on the intermediate ring 6.

[0052] In the illustrated embodiment, the conical outer circumference 8 of the intermediate ring 6 has a hardened surface quality comprising an average roughness Ra in the range of from 1.5 to 15 The corresponding conical through opening 5 has a lower hardness, so that the micro-projections on the conical outer circumference 8 claw into the softer material of the first component of the hub 1.

[0053] In the same way, to increase the friction toward the shaft 10, the inner circumference of the cylindrical through opening 7 of the reduction sleeve 6 can have a hardened surface quality comprising an average roughness Ra in the range of from 1.5 to 15 μm.

[0054] The interference fit connection explained above is preferably joined hydraulically. In this case, in one embodiment, the reduction sleeve 6 is first pushed onto the shaft 10. If necessary, the reduction sleeve 6 can first be heated for this purpose. The hub 1 is then assembled on the reduction sleeve. Said hub is first pushed axially onto the reduction sleeve 6 as far as possible. To allow a hydraulic force to be applied for the purpose of subsequent pressing on, a closure plug 11 is attached to the reduction sleeve 6 and axially closes a chamber 12 formed between the hub 1 and the reduction sleeve 6. Furthermore, at least one hydraulic connection 13 is provided on the hub 1 in order to apply a hydraulic medium to the chamber 12 for pressing the hub 1 onto the reduction sleeve 6. Said reduction sleeve is discharged again after assembly.

[0055] The configuration explained above allows significant weight saving compared to conventional one-component hubs made of steel.

[0056] The hydraulic assembly also contributes to this, allowing a particularly compact design.

[0057] This can be further increased by the friction-increasing measures explained above, in particular on the reduction sleeve 6, since this allows high torques to be transmitted in a non-positive manner.

[0058] The invention has been explained in detail above with reference to an embodiment and further variants. The embodiment and the variants serve to prove the feasibility of the invention. Technical individual features which were explained above in the context of further individual features can also be implemented independently of said further individual features and in combination with other individual features, even if this is not expressly described, as long as this is technically possible. The invention is therefore expressly not limited to the embodiment specifically described and the variants explained above, but includes all embodiments defined by the claims.

LIST OF REFERENCE SIGNS

[0059] 1 Hub [0060] 2 Sleeve portion [0061] 2a Gradated region [0062] 3 Flange portion [0063] 4. Attachment structure [0064] 5 Conical through opening [0065] 6. Reduction sleeve [0066] 7. Cylindrical through opening [0067] 8. Conical outer circumference [0068] 9 Ring [0069] 10 Shaft [0070] 11 Closure plug [0071] 12. Chamber [0072] 13 Hydraulic connection [0073] h Height of gradation [0074] s Mean wall thickness of the first component in the gradated region 2a [0075] t Wall thickness of the ring 9