Hose extrusion head and method for producing a hose

Abstract

The invention relates to a hose extrusion head for producing a hose (50), said head comprising a head housing, a duct (14) formed in the head housing (12) for supplying a hose material (22), a pin (16) which is arranged in the duct (14), a die (18) and at least one securing element (20). According to the invention, the securing element (20) is attached by one end (39) to the die (18) such that said end (39) follows the movement of the die (18).

Claims

1. A hose extrusion head for producing a hose, said hose extrusion head, comprising: a head housing; a duct formed in the head housing for supplying a hose material; a phi arranged in the duct; a die movable relative to the pin for centering; and at least one securing element configured to attach the die to the head housing, said securing element having one end attached to the die such that the end follows a movement of the die, wherein the at least one securing element is a pre-tensioned wire cable.

2. The hose extrusion head of claim 1, wherein the die lies against the head housing at a contact surface, said securing element being configured to clamp the die toward the contact surface.

3. The hose extrusion head of claim 1, wherein the securing element is arranged such that a mass force, which is exerted by the hose material in an operating state of the hose extrusion head on the die, reduces a frictional force between the die and the head housing.

4. The hose extrusion head of claim 1, wherein the securing element is fixed in a head housing attachment point relative to the head housing and attached to the die in a die attachment point, said head housing attachment point being arranged upstream to the die attachment point with respect to an inflow path of the hose material.

5. The hose extrusion head of claim 1, wherein the die comprises a die insert, and a die insert holder including an axial adjusting device having an axial adjusting device for adjusting an axial position of the die insert relative to the die insert holder.

6. The hose extrusion head of claim 1, further comprising a positioning device configured to alter a position of the die relative to the pin so as to enable centering of the die relative to the pin.

7. The hose extrusion head of claim 6, wherein the positioning device is a part of a position regulation and includes at least one drive for automatically changing the position of the die, said position regulation further including a wall thickness measuring device for measuring a wall thickness of the hose, said wall thickness measuring device being configured for automatically changing the position of the die so as to prevent the wall thickness of the hose to fall below a predetermined nominal wall thickness and to minimize an overall deviation of the wall thickness from the predetermined nominal wall thickness.

8. The hose extrusion head of claim 1, further comprising a seal arranged between the die and the head housing.

9. A hose production device for producing a hose, said hose production device comprising: an extruder for delivering hose material; and a hose extrusion head comprising a head housing, a duct formed in the head housing for supplying a hose material, a pin arranged in the duct, a die movable relative to the pin for centering, and at least one securing element configured to attach the die to the head housing and having one end attached to the die such that the end follows a movement of the die, said hose extrusion head being connected with the extruder so that, in operation, the extruder delivers the hose material into the duct, wherein the at least one securing element is a pre-tensioned wire cable.

10. The hose production device of claim 9, wherein the die lies against the head housing at a contact surface, said securing element being configured to clamp the die toward the contact surface.

11. The hose production device of claim 9, wherein the securing element is arranged such that a mass force, which is exerted by the hose material in an operating state of the hose production device on the die, reduces a frictional force between the die and the head housing.

12. The hose production device of claim 9, wherein the securing element is fixed in a head housing attachment point relative to the head housing and attached to the die in a die attachment point, said head housing attachment point being arranged upstream to the die attachment point with respect to an inflow path of the hose material.

13. The hose production device of claim 9, wherein the die comprises a die insert, and a die insert holder including an axial adjusting device having an axial adjusting device for adjusting an axial position of the die insert relative to the die insert holder.

14. The hose production device of claim 9, wherein the hose extrusion head includes a positioning device configured to alter a position of the die relative to the pin so as to enable centering of the die relative to the pin.

15. The hose production device of claim 14, wherein the positioning device is a part of a position regulation and includes at least one drive for automatically changing the position of the die, said position regulation further including a wall thickness measuring device for measuring a wall thickness of the hose, said wall thickness measuring device being configured for automatically changing the position of the die so as to prevent the wall thickness of the hose to fail below a predetermined nominal wall thickness and to minimize an overall deviation of the wall thickness from the predetermined nominal wall thickness.

16. The hose production device of claim 9, wherein the hose extrusion head includes a seal arranged between the die and the head housing.

17. The hose production device of claim 9, wherein the hose material is rubber.

Description

BRIEF DESCRIPTION OF THE DRAWING

(1) The invention is explained in further detail below with the aid of the enclosed drawings. There are shown:

(2) FIG. 1 a hose extrusion head according to the invention in a cross-section and in a longitudinal section,

(3) FIG. 2 the cross-section of the hose extrusion head according to FIG. 1, after the die was decentred and

(4) FIG. 3 the hose extrusion head according to the preceding figures after actuation of an axial adjusting device.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

(5) FIG. 1 shows a hose extrusion head 10 according to the invention, with a head housing 12, in which a duct 14 is formed. In the duct 14 there is situated a pin 16, which is rigidly connected to the head housing 12 in a detachable manner. A hatching serves to illustrate an object and is not necessarily to be regarded as an indication of a section.

(6) The hose extrusion head 10 has in addition a die 18 which is attached to the head housing 12 via securing elements 20. In FIG. 1 the securing elements 20.1, 20.2, 20.3 and 20.4 are drawn (reference numbers without numerical suffix refer respectively to all corresponding objects). The number of the securing elements is, however, able to be freely selected in wide limits.

(7) In operation, the duct 14 is filled with hose material 22. The hose material 22 is usually rubber. The hose material 22 flows along an inflow path 24, which is indicated by arrows, toward the die 18.

(8) In the present embodiment, the die 18 comprises a die insert 26 and a die insert holder 28. The die insert holder 28 has an axial adjusting device 30. In the embodiment shown in FIG. 1, the axial adjusting device 30 is formed by a ring with an external thread, which meshes with the die insert holder 28. By turning the ring about its longitudinal axis (in the present case about the z-axis), the axial position of the die insert 26 relative to the die insert holder 28 can be altered. The axial position is the height with respect to the z-axis which corresponds to a longitudinal axis of the pin 16. According to an alternative embodiment, the die 18 can be embodied in one piece.

(9) The securing element 20 comprises tensioning elements, in the present case tensioning wire cables 32, of which the tensioning wire cables 32.1, 32.2 are shown. The tensioning wire cables 32 are pre-tensioned by tensioning devices 34 so that they transmit a tension force F.sub.tens onto the die 18.

(10) The die 18 lies in a contact surface 36 against the head housing 12. When a travel motion occurs, therefore a movement in the x-y plane, an actuating force F.sub.act, which is greater than a frictional force F.sub.fric, must be applied for this onto the die 18.

(11) As is shown diagrammatically, the hose material 22 exerts a mass force F.sub.M on the die 18. The term mass force is selected here because the hose material, which can also be designated as the mass to be processed, exerts this force. The term mass force is not to be understood to the effect that it comes about primarily through the inertia of deflected masses. In the figures, the forces are recorded without a vector arrow, for the sake of simplicity. Of course, the forces are all vectorial quantities.

(12) As is shown diagrammatically, the mass force F.sub.M can be broken down vectorially into an axially acting force F.sub.a and a radially acting force F.sub.r. The axial portion F.sub.a counteracts the tension force F.sub.tens. That means that a vector addition of the tension force F.sub.tens and of the axial portion F.sub.a of the mass force F.sub.M has a smaller amount than the tension force F.sub.tens. The die 18 exerts on the contact surface P a surface pressing p.sub.36, which can also be understood as pressure. Through the action of the mass force F.sub.M, the surface pressing p.sub.36 reduces. Thereby, the frictional force F.sub.fric decreases with increasing mass force F.sub.M.

(13) The securing elements 20 have respectively a head housing attachment point 38 and a die attachment point 40. Each securing element 20 has a first end 39, by which it is attached to the die 18 in the respective die attachment point 40. The securing element 20 lies with a clamping surface 41 against the die 18. The head housing attachment point 38 is formed at a second end 43 of the securing element 20.

(14) The die attachment point 40 is arranged downstream relative to the head housing attachment point 38, which means that the hose material 22 firstly flows past in the vicinity of the head housing attachment point and thereafter in the vicinity of the die attachment point. In this way, the action of the mass force F.sub.M described above comes about in relation to the tension force F.sub.tens.

(15) In the right-hand partial image, it is shown that that the hose extrusion head 10 comprises a positioning device 42. In the present embodiment, the positioning device 42 comprises two drives 44.1, 44.2, which comprise respectively a ball screw and a motor for driving the ball screw. By actuating the drives 44.1, 44.2, the die 18 can be centred relative to the pin 16.

(16) The drives 44 are connected by diagrammatically drawn cables with a position regulation 46. The position regulation 46 is, in addition, in connection with a wall thickness measuring device 48, by means of which a wall thickness S of a hose 50 which is to be manufactured is measured. The position regulation 46 detects continuously whether the wall thickness S corresponds to a nominal wall thickness. If a deviation is detected, the position regulation 46 actuates the drives 44 so that any decentring is remedied or at least reduced. In addition, it is possible that the hose extrusion head 10 has an automatic axial adjusting device, which is likewise connected with the position regulation 46.

(17) FIG. 2 shows the case in which the die 18 has been moved relative to the head housing 12 by actuating of the drive 44.1. It can be seen that the die 18 is now arranged in an uncentred manner relative to the pin 16.

(18) FIG. 3 shows the effect of an adjustment of the axial adjusting device 30. It can be seen that the die insert 26 has been moved further towards the pin 16. As the pin 16 is constructed conically at its end facing the die 18, through this movement the wall thickness S of the hose 50 reduces. The hose extrusion head 10 according to the invention therefore makes it possible to adjust both the wall thickness S and also the wall thickness differences by centring the die 18.