DE3329967A1 - Screwed or riveted connection - Google Patents

Abstract

The invention relates to a screwed or riveted connection which connects various components, which rest on one another, to one another along a contact gap. The components are provided with a coating, even in the contact region, which coating prevents corrosion and is softer than the basic material, especially with a varnish. In the contact gap, a washer is placed around the screw or rivet shaft, which washer, on its flat side facing the varnished contact surface, is provided uniformly with blade-like beads which penetrate through the varnish down to the basic material, or with a large number of acute-angled pyramids. The washer material has at least approximately the same hardness as the basic material of the components which are to be connected. Such washers are intended to contribute to reducing the appearances of settlement in dynamically stressed screwed or riveted connections having varnished clamping surfaces. In this case, the washers can be fitted both in the contact gap of the clamping surface as well as under the screw or rivet head and/or under the nut.

Description

Screw or rivet connection

The invention relates to a screw or rivet connection according to The preamble of claim 1, as known for example from DE-AS 1182 903 emerges.

For dynamically stressed screw or rivet connections with painted clamping surfaces, As they are, for example, in vehicle construction, with frames for trucks and with axles Screw-on parts are used, settlement phenomena occur during operation can lead to a loss of prestressing force and thus to loosening of the connection. A remedy must therefore be found against loosening during operation.

In the above citation, a lock for screws and nuts, it is a radial serration with a sawtooth cross-section on the contact surface of the screw head or the nut.

These blade-like parts work their way into the support surface and generate an increased resistance at least in the direction of loosening the screw connection. This is to prevent accidental loosening of the screw or nut.

The also previously known DE-OS 25 52 964 describes a method and means for tightening a screw connection through artificially guided equiaxed ones Strikes the screw connection to cause it to settle.

A large number of other references include spring washers known with ratchet teeth in the most diverse forms, which are cutting edge in work in the support surface of the component to be connected in order to secure it; for example, this is done by expressions with thorn-like approaches in the Shape of spikes, pyramids or tongues or wavy bulges or ring beads.

A disadvantage of these embodiments, however, is that this After tightening, largely compress the securing elements, i.e. they are flexible and in the case of painted parts do not completely penetrate the paint layer, see above that although a momentary protection against loosening of the connection is effected, but Settlement phenomena under dynamic stress and therefore no loosening be prevented. Therefore, important screw connections must be made after the setting process retightened to compensate for the loss of preload caused by the slow flattening of roughness peaks in the threads and in the contact surfaces of the components to be screwed.

Since the setting process is very slow, it is often necessary to retighten the screw connections are dispensed with at all, which under certain circumstances visible Can lead to consequential damage.

However, the continuous tightening of screw connections is time-consuming, bothersome and costly. Incidentally, this is in some places for reasons of accessibility no longer possible or only with great difficulty.

The object of the invention is therefore to design a screw connection underlying type to the effect that this strengthens even without retightening in spite of dynamic stress, at most only slightly and to a tolerable extent decreases, i.e. limitation of the loss of prestressing force of the connection.

According to the invention, this object is achieved by the characterizing features solved by claim 1.

The design of the blade-like beads or

Solid pyramids on the washer are guaranteed, that this the corrosion-preventing coating - mostly in the form of a paint job - penetrate the components to be connected down to the base material and thus a setting process in the screw or rivet connection is only very limited Dimensions. can take place, even with leakage of the paint, for example with strong Heating in the contact gap. The required preload force also becomes more dynamic Stress still adhered to without any signs of loosening. try on vibration test stands of a screw manufacturer have in this context an optimized disc element remaining loss of pre-tensioning force of approx. 10% of the assembly preload. The profile of this disc element must be designed in such a way that, on the one hand, when a screw is tightened, the Approx. 0.1 mm thick layer of lacquer penetrates, but still as little as possible penetrates into the metallic substrate. The setting behavior of such a screw connection is also dependent on many parameters and is therefore difficult to calculate capture.

Normally, the subject of the invention is a Different screw or rivet connections along a contact gap Adjacent painted components, where in the contact gap around the screw or A rivet shank around a washer with knife-edge ridges or pyramids is inserted. According to claim 2, however, the formation of a recess in the Contact gap due to the shape of the components according to the size of the washer possible, i.e. that between the components to be connected there is space for a profiled Washer is created.

The blade-like beads can be designed as concentric circular beads or as individual bumps leading radially outwards or as evenly distributed pointed pyramids on one or both sides of the washer. at If the execution is on both sides, the beads or pyramids are to be arranged exactly opposite one another, to improve the power flow.

With regard to the dimensioning, the bulge or

The height of the pyramids is about 0.2 to 0.3 millimeters and the Edge radius with approx. 0.02mm. The flank inclination of the bulges or pyramids opposite the contact surface should be about 450 each, so that an angle of about 900 for the surveys comes about.

Finally, in the configuration, the underlying type of screw connections the attachment of the washers under the screw or rivet head and / or provided under the mother.

The advantages achieved by the invention are mainly due to the measures described the old problem of the setting behavior of screwdrivers or Riveted connections on painted surfaces with regard to the loss of prestressing force and the resulting loosening of the connection to a tolerable extent to limit dynamic stress. Due to the massive one-sided or two-sided Elevations of the washers in connection with a material of at least the same Hardness like the base material of the components to be connected is a penetration of the Paint or corrosion layer guaranteed.

The invention is based on exemplary embodiments in the drawings and is described in more detail below. They show: FIG. 1 a Screw connection according to the invention of two components with a washer with blade-like Bulges in the contact gap Figure 2 is the perspective view a washer with massive concentric circular beads, Figure 3 the perspective Representation of a washer with radially outward leading evenly on the circumference distributed linear individual elevations, Figure 4 is a perspective view of a Washer with a multitude of the same.

moderately distributed pointed pyramids, FIG. 5 the enlarged view the installation conditions in the contact gap of a screw connection with a section through the washer and the components to be connected, Figure 6 shows an embodiment a screw connection according to the invention, in which a cylindrical recess half of each is attached to accommodate the washer in the components is, and Figure 7 is a corresponding embodiment with a recess for Placement of the washer on one of the components.

The screw (or rivet) connection 1 shown in FIG. 1 exists from the components 11 and 12 to be connected to one another in the contact gap 2 and the between clamped washer 3 around the screw (or Rivet) shank 4 is inserted around. The blade-like arranged on both sides Beads 8 penetrate the paint 5 or other corrosion-preventing coating on the contact surface 6 down to the base material 10 of the components 11 and 12.

As an exemplary embodiment, FIG. 2 shows the perspective illustration a washer 3 with massive concentric circular beads 8 around the central axis the washer.

In Figure 3, a washer 3 'is shown with radially outward leading linear beads 8 'and Figure 4 evenly distributed on the circumference a 3 "washer with a multitude of evenly spaced pointed pyramids 9. In all exemplary embodiments, the bead or pyramid height is approximately 0.2 up to 0.3 mm and the edge radius about 0.02 mm.

For washers with bulges or pyramids on both sides these are to be arranged exactly opposite one another in order to thus reduce the flow of force of the Improve screw or rivet connection.

FIG. 5 illustrates the installation conditions in an enlarged representation in the contact gap 2 of a screw connection with a section through the washer 3 and the components to be connected 11 and 12, which are coated with paint 5 or another Corrosion-preventing coating are provided with a layer thickness s of average about 0.1 mm. In contrast, the height of the beads 8 or pyramids is 9 h = 0.2 to 0.3 mm and the edge radius r = y O, Q2 mm. The tips of the bulges or Pyramids protrude into the base material after the screw connection has been tightened 10 of the components 11 and 12, i.e. they penetrate the paint 5 completely.

Finally, FIGS. 6 and 7 each show a screw connection 1, in which the components 11 and 12 to be connected are in full contact with one another and only in the area around their through holes 17, 18 around a recess 13, 14 is formed according to the size of the washer 3. In the exemplary embodiment according to Figure 6, the recess 13 for accommodating the washer 3 is depending on the Half mounted in components 11 and 12; in Figure 7, however, is the recess 14 arranged only in the component 11, while the component 12 apart from the through hole 18 has no further recess for the screw connection. In the working examples according to FIGS. 6 and 7, the depth t of the recess must be dimensioned accordingly be that the required preload of the screw connection is achieved when tightening becomes, i.e. the depth t must on no account be dimensioned too large.

According to claim 8 it is with the screw connection according to the invention possible that the washers 3 also under the screw or rivet head 15 and / or are attached under the nut 16. This mainly creates the safety effect the screw connection is reinforced against loosening. When the contact surfaces from the screw head 15 and the nut 16 are also painted on the components 11, 12, occurs Securing effect against setting processes of the screw connection 1 as in the contact gap 2 between the components themselves is also positive here. Another benefit is there in this case that normal commercial screws and nuts can be used and thus in addition to the washers according to the invention no further securing elements are necessary, neither against loosening of the screw connection still through setting processes.

The invention described is applicable to all dynamically stressed screw or riveted joints with painted surfaces can be used and is otherwise light Can be assembled with common tools and, if necessary, also disassembled without destruction. The profiling and design of the Washer can be used for important connections on the vibration test bench and others Facilities are optimized.

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Claims (8)

Claims g1 screw or rivet connection of various enteines Contact gap adjoining each other also in the contact area with a corrosion-preventing Coating, which is softer than the base material, of provided components, characterized in that that at least one in the contact gap (2) around the screw or rivet shank (4) Washer (3) is inserted, which is provided on the one with a coating (5) Contact surface (6) facing flat side (7) evenly with blade-like, the Coating up to the base material penetrating beads (8) or with a large number pointed pyramids (9) is provided and made of a material of at least approximately the same Hardness like the base material (10). 2. screw or rivet connection according to claim 1 d a d u r c h g e It is not shown that a recess (13, 14) in the contact gap (2) accordingly the size of the washer (3) formed by the shape of the components (11, 12) is. 3. screw or rivet connection according to claim 1 or 2, characterized in that that the beads (8) as concentric circular beads around the central axis of the washer (3) are arranged. 4. screw or rivet connection according to any one of claims 1-3 characterized in that the bulge or pyramids - height is hmb 2 3 3 xl TOffim. 5. screw or rivet connection according to any one of claims 1-4 characterized in that in the case of washers (3) with beads (8) attached on both sides or pyramids (9), these are each arranged exactly opposite one another. 6. screw or rivet connection according to any one of claims 1-5 characterized in that the edge radius of the beads (8) or pyramids (9) = s 0.02 mm amounts to. 7. screw or rivet connection according to any one of claims 1-6 characterized in that the flank inclination of the beads (8) or pyramids (9) opposite the contact area is about 450 each. 8. screw or rivet connection according to any one of claims 1-7 characterized in that the washers (3) also under the screw or. Rivet head (15) and / or under the nut (16) are attached.