GB2292434A

GB2292434A - Vibration-damping bush

Info

Publication number: GB2292434A
Application number: GB9515481A
Authority: GB
Inventors: Bruno Hezel
Original assignee: Robert Bosch GmbH
Current assignee: Robert Bosch GmbH
Priority date: 1994-08-11
Filing date: 1995-07-28
Publication date: 1996-02-21
Anticipated expiration: 2015-07-28
Also published as: DE9412946U1; GB9515481D0; FR2723626A1; FR2723626B1; GB2292434B

Abstract

A bush (10) for receiving a fastening screw (40) is proposed, which bush serves for connecting a first component (20) to a second component (30). The bush (10) has a metallic sleeve (11), onto the outer circumferential surface (13) of which a flexible sheathing (16) of an elastomer is vulcanized. <IMAGE>

Description

Vibration-dampina bush Prior art The invention relates to a vibration-damping bush for a fastening screw of the generic type of the main claim. When fitting in particular components which are capable of resonating onto machine elements, there is the requirement to damp the transmission of vibrations of the machine elements to the component capable of resonating or to isolate the component acoustically. Owing to the low thermal stability of plastic components, there is also the requirement for a thermal isolation of these components. It is generally known for the vibration damping or acoustic isolation between component and machine element to attach vibration damping elements, such as for example rubber discs or the like.For absorbing axial stresses of the fastening screws, shims which to the greatest extent cannot be deformed are necessary in addition to the rubber discs.

Advantages of the invention The invention with the characterizing features of the main claim has the advantage that a single component can be used both for the vibration damping and for the absorption of the axial stresses of the fastening screws.

Advantageous developments of the invention are possible by the measures specified in the subclaims. Of particular advantage is the captiveness of fastening screw and bush. The captiveness of bush, fastening screw and component contributes furthermore, to the fact that the component can be used in the preassembled state.

Drawing An exemplary embodiment of the invention is explained in more detail in the drawing and in the following description. Figure 1 shows a sectional representation of a bush according to the invention and Figure 2 shows a sectional representation of a second embodiment of the bush according to the invention in interaction with components to be connected.

Exemplary embodiment The bush 10 according to Figure 1 has a sleeve 11 with a bore 12 and a circumferential surface 13, the bush 10 having a height h. Formed onto the sleeve 11 is a disc 14, which in the present exemplary embodiment is realized, for example, by pressing the sleeve 11 onto a single disc. At the other end face 15', the sleeve 11 is configured with a wall thickening 15, which serves for increasing the bearing surface of the sleeve 11.

The outer circumferential surface 13 is provided with a flexible sheathing 16, which is pro.duced by vulcanizing an elastomer, for example rubber, onto the sleeve 11. Understood here by elastomer are any types of flexible plastics. The sheathing 16 is taken up to the disc 14 and has there a thickening 17. On the remaining circumferential surface 13 of the sleeve 11, the sheathing 16 is uniformly formed. In this region of the sheathing 16, there may be formed on, according to Figure 2, a bead 18, which is configured for example in a circumferential form.

The bore 12 serves for receiving a fastening screw 40 according to Figure 2. The surface of the bore 12 is provided with a flexible lining 19. The lining 19 has a clear width d1 and reaches, for example, down to a depth t1, so that the remaining section of the bore 12, with a depth t2, has no lining, t2 being equal to h - t,.

The clear width d, is slightly smaller than the thread diameter of the fastening screw, so that the fastening screw 40 can be inserted through the bore 12 with little expenditure of force. Like the sheathing 16, the lining 19 is produced by vulcanizing on an elastomer. The partial lining of the bore 12 makes it possible for the thread of the fastening screw 40 inserted into the bore 12 to be able to be pushed back to the greatest extent into the bore 12 and at the same time is held captively in the bore 12.

Figure 2 shows a first component 20, which is connected to the fastening screw 40 by a second component 30. The fastening screw 40 has a screw head 41, a screw shank 42, with a diameter D1, and a thread 43, with a thread diameter D2.

The first component 20 has a depression 21, which is adjoined by a through-hole 22. Formed between depression 21 and through-hole 22 is an axial shoulder 23, which is expediently configured as a slope descending towards the through-hole 22. On the side opposite the depression 21, the through-hole 22 is adjoined by a relief 24. The second component 30 has a threaded bore 31, into which the thread 43 of the fastening screw 40 is screwed.

In the case of the bush 10 according to Figure 2, the lining 19 extends over the entire surface of the bore 12, including over the end face 15' of the sleeve 11, in this case the thread 43 not being able to be pushed back into the bore 12, as in the case of the sleeve according to Figure 1.

The bush 10 is inserted, according to Figure 2, into the through-hole 22, the thickening 17 supporting itself on the axial shoulder 23. The height h of the bush 10 is in this case chosen such that the bush 10 protrudes slightly out of the first component 20, so that in the fitted state the bush 10 supports itself by the annular surface 15', or by the elastomer covering the annular surface 15', on the second component 30.

The diameter of the through-hole 22 is in this case chosen such that the bead 18 can, on account of its flexible action, be pressed through with little expenditure of force and the bead 18 positions itself in the depression 24. This ensures that the bush 10 is held captively in the component 20. The fastening screw 40, guided in the bore 12 of the sleeve 10, rests by the screw head 41 on the disc 14. Upon screwing of the fastening screw 40 into the threaded bore 31 of the second component 30, the thickening 17 is pressed onto the axial shoulder 23, so that, on account of the flexible action of the sheathing 16 against the axial shoulder 23, a seal can be realized between component 20 and bush 10.

Claims

1. Vibration-damping bush for receiving a fastening screw, characterized in that a flexible sheathing (16) of an elastomer is vulcanized at least partially onto the outer circumferential surface (13) of a metallic sleeve (11).

2. Bush according to Claim 1, characterized in that the sleeve (11) has on the bearing surface of the fastening screw (40) a disc-shaped formation (14).

3. Bush according to Claim 2, characterized in that, adjoining the disc-shaped formation (14), the flexible sheathing (16) has a thickening (17).

4. Bush according to Claim 1, characterized in that the through-bore (12) of the sleeve (11) is configured at least partially with a flexible lining (19).

5. Bush according to Claim 4, characterized in that the lining 19 has a clear width d1 which is slightly smaller than the thread diameter of the fastening screw (40).

6. Bush according to Claim 4, characterized in that the lining (19) is configured down to a depth t of the through-bore (12) of the sleeve (11) and in that the remaining depth t2 corresponds approximately to the length of the thread (43) of the fastening screw (40).

7. Bush according to Claim 1, characterized in that the sheathing (16) is configured with a bead (18) in such a way that, as captivation, the bead (18) engages behind a through-hole of the part (20) to be connected.

8. Bush according to Claim 1, characterized in that, at the end face opposite the disc-shaped formation (14), the sleeve (11) has a wall thickening (15) for the formation of an enlarged annular surface (15').

9. A vibration damping bush substantially as herein described with reference to the accompanying drawing.