Mounting a ceramic roller in a roller hearth furnace

Abstract

Sleeve for mounting a ceramic roller in a roller hearth furnace, the sleeve has a receptacle for one end of the ceramic roller, the receptacle being surrounded by a lateral wall. The lateral wall has, in the axial direction, a waist portion and a clamping portion, wherein a wall thickness (d) of the lateral wall in the waist portion is smaller than in the vicinity of the waist portion, and a cross-sectional area of the receptacle in the clamping portion is smaller than in the vicinity of the clamping portion. A ceramic roller can be mounted in a roller hearth furnace by the sleeve, even at high temperature. During production, the sleeve is provided with a reduced cross-sectional area in the clamping portion. When the sleeve is pressed axially onto the end of a ceramic roller, the reduced cross-sectional area produces an elastic force, with the sleeve being held on the ceramic roller.

Claims

1. Sleeve for mounting a ceramic roller in a roller hearth furnace, wherein the sleeve has a receptacle for one end of the ceramic roller, wherein the receptacle is surrounded by a lateral wall, wherein the lateral wall has, in the axial direction, a waist portion and a clamping portion, the clamping portion being located inside the waist portion, such that the clamping portion does not protrude beyond or coincide with the waist portion, wherein a wall thickness (d) of the lateral wall in the waist portion is smaller than a wall thickness (d) of first and second portions of the lateral wall that are on respective first and second sides of the waist portion, and wherein a cross-sectional area of the receptacle in the clamping portion is smaller than a cross-sectional area of the receptacle that is adjacent to the clamping portion.

2. Sleeve according to claim 1, wherein the wall thickness (d) of the lateral wall in the waist portion is 20 to 60% of the wall thickness (d) of the lateral wall than that which is adjacent to the waist portion.

3. Sleeve according to claim 1, wherein the cross-sectional area of the receptacle in the clamping portion is 0.03 to 0.3% smaller than that which is adjacent to the clamping portion.

4. Sleeve according to claim 1, wherein an axial extension (l.sub.K) of the clamping portion is at least 70% of an axial extension (l.sub.T) of the waist portion.

5. Sleeve according to claim 1, wherein the waist portion has an axial extension (l.sub.T) in the range of 40 to 80% of an axial extension (l.sub.A) of the receptacle.

6. Set comprising a ceramic roller for a roller hearth furnace and a sleeve for mounting the ceramic roller in the roller hearth furnace, wherein the sleeve has a receptacle for one end of the ceramic roller, wherein the receptacle is surrounded by a lateral wall, wherein the lateral wall has, in the axial direction, a waist portion and a clamping portion, the clamping portion being located inside the waist portion, such that the clamping portion does not protrude beyond or coincide with the waist portion, wherein a wall thickness (d) of the lateral wall in the waist portion is smaller than a wall thickness (d) of first and second portions of the lateral wall that are on respective first and second sides of the waist portion, and wherein a cross-sectional area of the receptacle is smaller only in the clamping portion than a cross-sectional area of the end of the ceramic roller.

7. Method for mounting a sleeve on a ceramic roller for a roller hearth furnace, wherein the sleeve for mounting the ceramic roller in the roller hearth furnace is formed, wherein the sleeve has a receptacle for one end of the ceramic roller, wherein the receptacle is surrounded by a lateral wall, wherein the lateral wall has, in the axial direction, a waist portion, the clamping portion being located inside the waist portion, such that the clamping portion does not protrude beyond or coincide with the waist portion, wherein a wall thickness (d) of the lateral wall in the waist portion is smaller than a wall thickness (d) of first and second portions of the lateral wall that are on respective first and second sides of the waist portion, and wherein the method comprises: a) radial pressing of the sleeve in a clamping portion located in the waist portion, wherein the lateral wall is acted upon at at least three locations of the lateral wall by a force pointing radially inward in each case, b) axial pressing of the sleeve onto the end of the ceramic roller.

8. Method according to claim 7, wherein the sleeve after step a) is configured according to claim 1.

9. Method according to claim 7, wherein the cross-sectional area of the receptacle in the clamping portion becomes smaller than the cross-sectional area of the end of the ceramic roller by means of step b).

10. Method according to claim 7, wherein the sleeve is pressed in step b) with at least three press jaws which each extend circumferentially over an angular region of 10 to 60 of the lateral wall and/or which each extend axially over at least 80% of the waist portion of the lateral wall.

11. Sleeve according to claim 2, wherein the cross-sectional area of the receptacle in the clamping portion is 0.03 to 0.3% smaller than that which is adjacent to the clamping portion.

12. Sleeve according to claim 2, wherein an axial extension (lK) of the clamping portion is at least 70% of an axial extension (lT) of the waist portion.

13. Sleeve according to claim 2, wherein the waist portion has an axial extension (lT) in the range of 40 to 80% of an axial extension (lA) of the receptacle.

14. Sleeve according to claim 3, wherein an axial extension (lK) of the clamping portion is at least 70% of an axial extension (lT) of the waist portion.

15. Sleeve according to claim 3, wherein the waist portion has an axial extension (lT) in the range of 40 to 80% of an axial extension (lA) of the receptacle.

16. Sleeve according to claim 4, wherein the waist portion has an axial extension (lT) in the range of 40 to 80% of an axial extension (lA) of the receptacle.

17. Sleeve according to claim 1, wherein the cross-sectional area of the receptacle in the clamping portion is smaller than a cross-sectional area of first and second portions of the receptacle on respective first and second sides of the clamping portion.

Description

(1) FIG. 1: is a schematic sectional view of a roller hearth furnace having a ceramic roller which is mounted on two sleeves according to the invention,

(2) FIG. 2: is a schematic enlargement of a part of FIG. 1,

(3) FIG. 3: is a sectional view of the sleeve from FIG. 2,

(4) FIG. 4: is a side view of the sleeve from FIGS. 2 and 3,

(5) FIG. 5: is a cross-sectional view of the sleeve from FIGS. 2 to 4,

(6) FIG. 6: is a cross-sectional view of a part of a sleeve before radial pressing with a press jaw.

(7) FIG. 1 shows a roller hearth furnace 1 with a large number of ceramic rollers 2, one of which can be seen. The ceramic roller 2 is connected at both of the ends 5 thereof via a corresponding sleeve 3 according to the invention to a corresponding (only indicated) drive and mounting device 10 and, in this respect, is mounted via the sleeves 3. The part of FIG. 1 which is shown enlarged in FIG. 2 is drawn in dashed lines.

(8) It can be seen in FIG. 2 that the end of the ceramic roller 2 is received in a receptacle 4 of the sleeve 3. The receptacle 4 is surrounded by a lateral wall 6. This is shown in this case simplified with constant inside and outside radius. A gap is drawn in between the ceramic roller 2 and the sleeve 3. This is only for illustration in the view. In fact, the ceramic roller is circumferentially in contact with at least part of the lateral wall 6. The drive and mounting device 10 is also indicated in FIG. 2.

(9) FIG. 3 is a detailed and true-to-scale sectional view of the sleeve 3 from FIGS. 1 and 2 before assembly on the ceramic roller 2. It can be seen in FIG. 3 that the receptacle 4 is surrounded by a lateral wall 6, with the lateral wall 6 having a waist portion 7 in the axial direction and a clamping portion 8 located therein. A wall thickness d of the lateral wall 6 in the waist portion 7 is smaller than in the vicinity of the waist portion 7. A cross-sectional area of the receptacle 4 in the clamping portion 8 is smaller than in the vicinity of the clamping portion 8. However, this deviation is too small to be able to be recognized in the view of FIG. 3. The reduced cross-sectional area was achieved by means of step a) of the method according to the invention, after which the sleeve 3 is radially pressed in the clamping portion 8, wherein the lateral wall 6 is acted upon at at least three locations of the lateral wall 6 by a force pointing radially inward in each case.

(10) With step b) of the method according to the invention, the sleeve 3 can be mounted on the ceramic roller 2 in order to be used in the roller hearth furnace 1 from FIGS. 1 and 2. For this purpose, the sleeve 3 is pressed axially onto the end 5 of the ceramic roller 2 and, in this respect, is connected to the ceramic roller 2 in a non-positive manner.

(11) Also shown are an axial extension l.sub.T of the waist portion 7 and an axial extension l.sub.K of the clamping portion 8. In addition, an axial extension l.sub.A of the receptacle 4 is shown.

(12) Furthermore, a hexagon socket 11 can be seen, via which the sleeve 3 can be positively connected to the drive and mounting device 10.

(13) FIG. 4 is a side view of the sleeve 3 shown in FIGS. 2 and 3. FIG. 5 is a cross-sectional view of this sleeve 3.

(14) FIG. 6 is a cross-sectional view of part of a sleeve 3 before radial pressing according to step b). From the sleeve 3 shown, the sleeve 3 from FIGS. 2 to 5 can be obtained by the radial pressing. Before radial pressing, the lateral wall 6 has a cylindrical shape. The lateral wall 6 is slightly deformed by radial pressing. R.sub.i,1 and R.sub.i,2 designate two distances between the inside of the lateral wall 6 and the axis of the lateral wall 6 (located outside the detail in FIG. 6). In addition, Ra denotes a distance between the outside of the lateral wall 6 and the axis of the lateral wall 6 (located outside the detail in FIG. 6). In the situation shown before radial pressing, the following applies: R.sub.i,1=R.sub.i,2. Radial pressing can be done with a press jaw 9, among other things. The pressing preferably takes place with at least three press jaws which are designed like the press jaw 9 shown and which are distributed evenly over the circumference of the sleeve 3. Due to the radial pressing, R.sub.i,2 is more strongly influenced than R.sub.i,1 due to the arrangement of the press jaw 9. The wall thickness remains unchanged during radial pressing.

(15) A ceramic roller 2 can be mounted particularly reliably in a roller hearth furnace 1 by means of the sleeve 3, even at high temperature. To achieve this, during production the sleeve 3 is provided with a reduced cross-sectional area in the clamping portion 8. When the sleeve 3 is pressed axially onto the end 5 of a ceramic roller 2, the reduced cross-sectional area in the clamping portion 8 produces an elastic force, by means of which the sleeve 3 is held on the ceramic roller 2.

LIST OF REFERENCE SIGNS

(16) 1 Roller hearth furnace 2 Ceramic roller 3 Sleeve 4 Receptacle 5 End 6 Lateral wall 7 Waist portion 8 Clamping portion 9 Press jaw 10 Drive and mounting device 11 Hexagon socket d Wall thickness l.sub.T Axial extension of the waist portion l.sub.K Axial extension of the clamping portion l.sub.A Axial extension of the receptacle R.sub.i,1 Inner distance before radial pressing R.sub.i,2 Inner distance before radial pressing R.sub.a Outer distance before radial pressing