Screw element for the connection of tubes and tube connection device having this screw element

Abstract

The invention relates to a screw element for the connection of tubes, preferably motor vehicle lines. A threading and at least one contact surface without threading are provided on the screw element. The screw element has an outer coating and an inner coating. The outer coating comprises a first polymer and nanoparticles of a first solid material. The inner coating may also comprise nonoparticles or a polymer.

Claims

1. A union screw for the connection of tubes, for motor vehicle lines, wherein a threading and a bottom contact surface without threading are provided on the union screw, wherein the union screw comprises a through bore and a screw head, wherein the through bore extends through the screw head, wherein the screw head comprises an underside contact surface, wherein the union screw has an outer coating and an inner coating, wherein the inner coating lies between the outer coating and a metal substrate of the union screw, wherein the outer coating comprises a first polymer and nanoparticles of a first solid material, wherein the union screw has an outer surface, wherein the outer coating covers at least 50% of the outer surface of the union screw, and wherein the friction coefficient 1 of the outer coating is greater than the friction coefficient 2 of the inner coating.

2. The union screw according to claim 1, wherein the inner coating is disposed in a region of the bottom contact surface.

3. The union screw according to claim 1, wherein the coating thickness of the outer coating is 0.5 to 10 m.

4. The union screw according to claim 1, wherein the coating thickness of the inner coating is 10 to 100 m.

5. The union screw according to claim 1, wherein the portion of the nanoparticles in the outer coating is 2% to 40% of the weight.

6. The union screw according to claim 1, wherein the inner coating comprises a polymer.

7. The union screw according to claim 1, wherein the inner coating comprises nanoparticles of a second solid material.

8. The union screw according to claim 7, wherein the portion of nanoparticles in the inner coating is 2% to 40% of the weight.

Description

DESCRIPTION OF THE DRAWINGS

(1) The invention shall be explained in greater detail below based on drawings depicting only one exemplary embodiment. Schematically shown therein are:

(2) FIG. 1 is a longitudinal section of a screw element according to the invention, designed as a threaded bolt, in an assembled state.

(3) FIG. 1a is a sectional view on an enlarged scale of a portion of the apparatus of FIG. 1.

(4) FIG. 2 is a side view of the threaded bolt from FIG. 1 schematically illustrating the layers of coating.

DETAILED DESCRIPTION

(5) In FIG. 1 a screw element designed as a threaded bolt 1 is screwed into a connecting element in the form of a connecting block 12. The threaded bolt 1 has a thread 3 in the form of an external thread for this, and the connecting block 12 has a blind hole 15 having an internal thread. Prior to the screwing, a tube 2 having a longitudinal axis L is inserted in the threaded bolt 1, such that by screwing in the threaded bolt 1, a flange 10 is clamped between the threaded bolt 1 and the connecting block 12.

(6) When the threaded bolt 1 is tightened via a bolt head 6 on the threaded bolt 1, the threaded bolt 1 presses against the flange 10 with a contact surface 4. At the same time, a sealing surface 11 of the flange 10 presses against a connecting surface 14 of the connecting block 12. A liquid-tight connection between the tube 2 and a line 13 integrated in the connecting block 12 is generated in this manner, such that brake fluid leakage is prevented.

(7) FIG. 2 shows the threaded bolt 1 from FIG. 1 incorporating the principles of the invention in a symbolic side view. The outer perimeter of the threaded bolt 1 symbolizes the coatings 7 and 8. The outer coating 7 covers the surface of the threaded bolt 1 in its entirety. The inner coating 8, on the other hand, is applied only to the contact surfaces 4 and 5 of the threaded bolt 1.

(8) The threaded bolt 1 is manufactured in the known manner. This manufacturing also comprises a corrosion protection coating, comprising zinc and nickel. The corrosion protection coating is then coated with a passivation coating, which protects, in turn, the zinc/nickel coating. The inner coating 8 is first applied thereto, and lastly, the outer coating 7 is applied.

(9) Both the inner coating 8 as well as the outer coating 7 comprise a binder made of a polycondensate. The polycondensate for the inner coating 8 binds molybdenum disulfide nanoparticles having an arithmetically determined particle size of 100 nm. The portion of molybdenum disulfide nanoparticles in the inner coating 8 is 10% by weight. The inner coating is applied with a coating thickness of 30 m.

(10) The outer coating 7 is provided with tungsten(IV) sulfide nanoparticles. The tungsten(IV) sulfide nanoparticles have a mean particle size of 180 nm, and make up 15% by weight of the outer coating 7. The coating thickness of the outer coating 7 is selected at 4 m. Both coatings 7, 8 are applied by means of spray drums.

(11) It must be understood that the threaded bolt of FIG. 1 is illustrative of an embodiment of the invention. The parameters of the coatings and their makeup may be varied consistent with the disclosure of the specification.

(12) Variations and modifications of the foregoing are within the scope of the present invention. It is understood that the invention disclosed and defined herein extends to all alternative combinations of two or more of the individual features mentioned or evident from the text and/or drawings. All of these different combinations constitute various alternative aspects of the present invention. The claims are to be construed to include alternative embodiments to the extent permitted by the prior art.