Installing ceramic rollers in roller hearth furnaces

Abstract

A sleeve (3) for mounting a ceramic roller (2) in a roller hearth furnace (1) includes a receiving portion (4) for one end (5) of the ceramic roller (2), the receiving portion (4) being surrounded by an outer wall (6), the outer wall (6) having, in the axial direction, a barrel portion (7) and a fastening portion (8) located in the barrel portion, the wall thickness (d) of the outer wall (6) at the barrel portion (7) being smaller than that near the barrel portion (7), and the cross-sectional area of ​​the receiving portion (4) at the fastening portion (8) being smaller than that near the fastening portion (8). The sleeve (3) allows the ceramic roller (2) to be accommodated particularly reliably in the roller hearth furnace (1), even at high temperatures. To achieve this, the cross-sectional area of ​​the sleeve (3) is reduced at the fastening portion (8) during manufacture. When the sleeve (3) is pressed against the end (5) of the ceramic roller (2) in the axial direction, an elastic force is generated due to the reduced cross-sectional area at the fastening portion (8), and this elastic force holds the sleeve (3) to the ceramic roller (2).

Description

[Technical Field]

[0001] The present invention relates to a sleeve for mounting a ceramic roller in a roller hearth furnace, to a set of a ceramic roller for a roller hearth furnace and said sleeve, and to a method for mounting said sleeve on a ceramic roller. [Background technology]

[0002] It is known to heat parts, particularly steel parts, in roller hearth furnaces. To this end, the parts can be moved through the furnace via a number of rollers. The rollers are often made of ceramic so that they can withstand the high temperatures within the furnace.

[0003] It is known that there are various options for mounting rollers in roller hearth furnaces. The connection between the ceramic rollers and the steel mounting elements is often problematic. Since steel has a significantly higher thermal expansion coefficient than ceramic, if a metal sleeve is placed externally on the ceramic, the excess pressure fit will be reduced at the high operating temperatures of such roller hearth furnace systems. As a result, the preload is reduced, which weakens the ability to transmit the drive torque.

[0004] The object of the present invention is to provide a sleeve that allows a ceramic roller to be attached to a roller hearth furnace with a sufficient press fit, even at high temperatures, based on the prior art described above. Furthermore, a set consisting of such a sleeve and a ceramic roller, and a method for installing such a sleeve on a ceramic roller are also presented. Summary of the Invention [Means for solving the problem]

[0005] These objects are achieved by the subject matter of the independent claims. The dependent claims specify further advantageous developments. The features presented in the claims and in this specification can be combined with one another in any technically significant manner.

[0006] The present invention provides a sleeve for mounting a ceramic roller in a roller hearth furnace. The sleeve has a receiving portion for one end of the ceramic roller, and the receiving portion is surrounded by an outer wall. The outer wall has, in the axial direction, a barrel portion and a fastening portion located in the barrel portion. The wall thickness of the outer wall at the barrel portion is smaller than that near the barrel portion, and the cross-sectional area of ​​the receiving portion at the fastening portion is smaller than that near the fastening portion.

[0007] The sleeve is designed and configured to mount a ceramic roller in a roller hearth furnace. The ceramic roller is preferably one of many ceramic rollers that are intended to be placed in the roller hearth furnace and to transport parts through the roller hearth furnace. The roller hearth furnace allows parts to be heat treated, such as for press hardening, and in particular steel parts. The roller hearth furnace is preferably designed to heat treat parts, in particular automotive parts.

[0008] The ceramic roller can be accommodated in the roller hearth furnace via two of several sleeves. The ceramic roller is preferably accommodated at both ends via corresponding sleeves. These two sleeves are preferably identical in design. To mount the ceramic roller, both ends of the ceramic roller are inserted into the corresponding sleeve receptacles. During operation, the sleeve is connected to the ceramic roller via a press fit. The sleeve is preferably positively connected to the drive and receiving device via a hexagonal fitting or the like. The part of the drive and receiving device connected to the sleeve is rotatably held by the remainder of the drive and receiving device, which does not move. In this way, the sleeve is an adapter between the drive and receiving device on one side and the ceramic roller on the other side. The sleeve thus provides a connection to the ceramic roller, through which the ceramic roller can be connected to the drive and receiving device.

[0009] To describe the sleeve, two axial portions of the outer wall are defined: a barrel portion and a fastening portion. The fastening portion is located inside the barrel portion. This means that the fastening portion does not protrude beyond the barrel portion to one side or to either side, and is not coincident with the barrel portion. In addition to the barrel portion and the fastening portion, the outer wall preferably has a further axial portion. It is particularly preferred that the barrel portion is spaced from the end face of the receiving part. The barrel portion and the fastening portion are defined by the conditions described below. Furthermore, it is not essential that the barrel portion and the fastening portion be defined as described above. In particular, it is possible to define different portions as barrel portions, or different portions as fastening portions, or both. It is only necessary that one portion can be defined as a barrel portion and one portion as a fastening portion. It is not important to allocate these portions in any other possible way.

[0010] The barrel portion is defined by the fact that the wall thickness of the outer wall in the barrel portion is smaller than that in the vicinity of the barrel portion. This means that the wall thickness of the outer wall is smaller in the barrel portion. It is preferable, but not necessary, that the wall thickness of the outer wall in the barrel portion is constant. Although not required, it is preferable that the wall thickness of the outer wall is constant even outside the barrel portion. Here, the term "constant" in both descriptions refers to the fact that the wall thickness does not change when viewed along the axial direction.

[0011] Since the barrel portion is defined in the axial direction, "proximate the barrel portion" should be understood to mean a portion of the outer wall that is adjacent to the barrel portion in the axial direction. Even in these portions, the wall thickness of the outer wall may not be constant. The wall thickness of the outer wall at the edge of the barrel portion is substantially the wall thickness of the outer wall "proximate the barrel portion." These edge portions are not considered to be part of the barrel portion.

[0012] The wall thickness is preferably constant when viewed in the circumferential direction, and this applies particularly to the entire outer wall. If the wall thickness can vary in the circumferential direction, any axial portion of the outer wall can be considered a barrel portion. For this barrel portion, the condition that the wall thickness of the outer wall at this portion is smaller than that of the vicinity of this portion is satisfied over at least a portion of the circumference of the outer wall. The condition that the wall thickness of the outer wall at the barrel portion is smaller than that of the vicinity of the barrel portion is preferably satisfied over the entire circumference of the outer wall at the barrel portion. Since the axial portion is taken into consideration, the "vicinity of this portion" is also defined in the axial direction. Therefore, only the vicinity of the portion at the corresponding location in the circumferential direction is important.

[0013] In the trunk portion, the wall thickness of the outer wall is preferably within a range of 0.5 to 1.0 mm.In the vicinity of the trunk portion, the wall thickness of the outer wall is preferably within a range of 1 to 2 mm.

[0014] The fastening portion is defined by the fact that the cross-sectional area of ​​the receiving portion at the fastening portion is smaller than that near the fastening portion. The cross-sectional area of ​​the receiving portion indicates the area of ​​the two-dimensional extent of the receiving portion when viewed perpendicular to the axis of the receiving portion. The receiving portion is a space surrounded by an outer wall. Therefore, the cross-sectional area of ​​the receiving portion is the area bounded by the inside of the outer wall when viewed perpendicular to the axis of the outer wall. The cross-sectional area of ​​the receiving portion at the fastening portion being smaller than that near the fastening portion means that the cross-sectional area of ​​the receiving portion is smaller at the fastening portion. It is preferable, but not necessary, that the cross-sectional area of ​​the receiving portion be constant even outside the fastening portion, although this is not essential. Here, the term "constant" in both descriptions refers to the fact that the cross-sectional area does not change when viewed along the axial direction.

[0015] Since the fastening portion is defined in the axial direction, "near the fastening portion" should be understood to mean the portion of the outer wall that is adjacent to the fastening portion in the axial direction. The cross-sectional area of ​​the receiving portion may not be constant in these portions either. The cross-sectional area of ​​the receiving portion at the edge of the fastening portion is essentially the cross-sectional area of ​​the receiving portion "near the fastening portion." These edge portions are not considered to be part of the fastening portion.

[0016] If the receiving part is cylindrical, the diameter of the receiving part within the clamping part is smaller than in the vicinity of the clamping part. However, it is not essential that the receiving part be strictly cylindrical. It is more preferable that the receiving part is deformed relative to its cylindrical shape, at least in the clamping part. To emphasize this possibility, the term diameter (which, according to the mathematical definition, indicates a circular cross-section) is not used for such deformed receiving parts. Instead, the distance between the inside of the outer wall and its axis is to be considered. If the receiving part is cylindrical, this distance corresponds to its radius. The smaller cross-sectional area of ​​the receiving part in the clamping part compared to the vicinity of the clamping part can be achieved in particular by the distance between the inside of the outer wall and its axis in the clamping part being smaller than in the vicinity of the clamping part.

[0017] The distance between the inner side of the outer wall and the axis of the outer wall does not have to be constant when viewed in the circumferential direction. As a result, the outer wall may not have a rotationally symmetrical shape. If the distance between the inner side of the outer wall and the axis of the outer wall varies in the circumferential direction, any axial portion of the outer wall where the distance between the inner side of the outer wall and the axis of the outer wall is smaller than in its vicinity can be considered a fastening portion. The center refers to a plane perpendicular to the axis of the outer wall. The condition that the distance between the inner side of the outer wall and the axis of the outer wall in the fastening portion is smaller than in the vicinity of the fastening portion is preferably satisfied throughout the entire circumference of the outer wall in the fastening portion. Since the axial portion is taken into consideration, the "vicinity of this portion" is also defined in the axial direction. Therefore, only the vicinity of the portion at the corresponding location in the circumferential direction is important.

[0018] In the vicinity of the fastened portion, the distance between the inside of the outer wall and the axis of the outer wall is preferably within a range of 24 to 100 mm. The distance between the inside of the outer wall and the axis of the outer wall in the fastened portion is preferably 0.15 to 1.00 mm smaller than in the vicinity of the fastened portion. Therefore, it is sufficient for the outer wall to deform relatively slightly.

[0019] The sleeve allows the ceramic roller to be accommodated particularly securely in a roller hearth furnace, even at high temperatures. Plastic deformation of the clamping portion during the sleeve's manufacture reduces the cross-sectional area of ​​the clamping portion. During assembly of the sleeve, this cross-sectional area is elastically expanded so that the minimum distance between the inner side of the outer wall and the axis of the outer wall in the clamping portion corresponds to the final cross-sectional area of ​​the ceramic roller. Due to the high radial force generated between the ceramic roller and the sleeve, the drive torque can be transmitted to the ceramic roller via the sleeve in a press-fit manner. The radial force is preferably equal to or less than the value that the ceramic roller must withstand. It has been found that the radial force resulting from the above-described design of the sleeve is sufficiently high for a press fit between the sleeve and the ceramic roller, despite the reduced margin due to the high temperatures and the different thermal expansion coefficients of the sleeve and the ceramic roller. The elasticity of the clamping portion is preferably designed to prevent permanent, i.e., plastic, deformation of the clamping portion under any operating conditions.

[0020] The outer wall is preferably closed in the circumferential direction. This applies to at least the axial portion, in particular at least the barrel portion or the clamping portion, or both. The outer wall is particularly preferably completely closed. The openings in the end faces are not openings in the outer wall. In particular, the outer wall does not have an axial groove. This configuration can be provided to compensate for differences in the expansion of the ceramic roller and the sleeve by the spring effect that can be achieved with such a configuration. However, this design significantly limits the stiffness of the sleeve, so that the required preload can only be maintained to a very limited extent. With this configuration, the aforementioned groove is unnecessary, especially due to the barrel portion and the clamping portion. As a result, the groove can be omitted, thereby improving the stability of the sleeve and its connection to the ceramic roller. Furthermore, manufacturing is simplified because no groove needs to be manufactured, which eliminates a manufacturing step.

[0021] In a preferred embodiment of the sleeve, the wall thickness of the outer wall in the trunk portion is 20 to 60% of the wall thickness of the outer wall in the vicinity of the trunk portion.

[0022] It has been found that the aforementioned advantages of reduced wall thickness can be achieved and that the outer wall is sufficiently stable in the barrel section.

[0023] In a further preferred embodiment of the sleeve, the cross-sectional area of ​​the receiving portion at the fastening portion is 0.03 to 0.3% smaller than that in the vicinity of the fastening portion.

[0024] It has been found that the aforementioned benefits of reduced cross-sectional area can be achieved and that the sleeve can be pressed against the ceramic roller without damaging the ceramic roller.

[0025] In a further preferred embodiment of the sleeve, the axial extent of the clamping portion is at least 70% of the axial extent of the barrel portion.

[0026] In particular, it is preferable that the axial extent of the tightening portion is between 70% and 90% of the axial extent of the trunk portion.

[0027] In a further preferred embodiment of the sleeve, the barrel portion has an axial extent in the range of 40 to 80% of the axial extent of the receiving portion.

[0028] It has been found that the aforementioned advantages of reduced wall thickness can be achieved and that the outer wall is sufficiently stable.

[0029] In a further aspect of the present invention, a set is provided that includes a ceramic roller for a roller hearth furnace and a sleeve for mounting the ceramic roller in the roller hearth furnace. The sleeve has a receiving portion for one end of the ceramic roller, and the receiving portion is surrounded by an outer wall. The outer wall has, in the axial direction, a barrel portion and a fastening portion located in the barrel portion. The wall thickness of the outer wall at the barrel portion is smaller than that near the barrel portion, and the cross-sectional area of ​​the receiving portion is smaller only at the fastening portion than at the end of the ceramic roller.

[0030] The special advantages and design features of the sleeves described above can be applied to this set and vice versa. The sleeves of this set are preferably designed similarly to the sleeves described above. The sleeves are not pressed against the ceramic rollers in the set. However, they are intended to be pressed against the ceramic rollers and are designed to do so. Preferably, the set includes two sleeves, one of which can be pressed against each end of the ceramic roller.

[0031] Thus, since the cross-sectional area of ​​the receiving portion is smaller than the cross-sectional area of ​​the end of the ceramic roller only at the clamping portion, the cross-sectional area of ​​the receiving portion at the clamping portion is smaller than that near the clamping portion. The cross-sectional area of ​​the end of the ceramic roller is the area covering the outside of the ceramic roller when viewed perpendicularly to the axis of the ceramic roller at the end of the ceramic roller. The end of the ceramic roller is part of the ceramic roller and is the part accommodated by the sleeve. If the cross-sectional area of ​​the ceramic roller at the end is not constant, the average value is important. Therefore, outside the clamping portion, the cross-sectional area of ​​the receiving portion is equal to or greater than the cross-sectional area of ​​the end of the ceramic roller. When the sleeve is pressed against the ceramic roller, the sleeve is held to the ceramic roller, particularly via the clamping portion. This is a clamping connection, which explains the term clamping portion.

[0032] In a further aspect of the present invention, there is provided a method for installing a sleeve on a ceramic roller for a roller hearth furnace, the sleeve being designed to mount the ceramic roller in the roller hearth furnace, the sleeve having a receiving portion for one end of the ceramic roller, the receiving portion being surrounded by an outer wall, the outer wall having a barrel portion in the axial direction, the wall thickness of the outer wall at the barrel portion being smaller than that in the vicinity of the barrel portion, the method comprising: a) radially compressing the sleeve at a clamping portion located in the trunk portion, wherein radially inward forces are applied to the outer wall at at least three locations on the outer wall; b) pressing the sleeve axially against the end of the ceramic roller; Includes.

[0033] The special advantages and design features of the aforementioned sleeves and sets can be applied and transferred to the present method, and vice versa. The aforementioned sleeves, in particular the sleeves of the aforementioned sets, are preferably obtained by step a) of the present method. According to step a), the sleeves are preferably designed like the aforementioned sleeves, in particular like the sleeves of the aforementioned sets. Step b) of the present method can be carried out using the aforementioned sleeves, in particular using the aforementioned sets, as appropriate. Step b) is preferably carried out using a device for axially pressing the sleeves against the ends of the ceramic rollers. To apply the necessary axial pressing force, the device preferably has a hydraulic drive. The present method is preferably carried out twice for each ceramic roller, by pressing a corresponding sleeve against each end of the ceramic roller.

[0034] In a preferred embodiment of the method, the cross-sectional area of ​​the receiving portion in the clamping portion is smaller than the cross-sectional area of ​​the end of the ceramic roller due to step b).

[0035] The receiving portion therefore initially has a cross-sectional area equal to or greater than the cross-sectional area of ​​the end of the ceramic roller. The cross-sectional area of ​​the receiving portion is preferably constant over the entire receiving portion. In particular, the cross-section of the receiving portion is preferably circular over the entire receiving portion. The same applies to the end of the roller. The cross-sectional area of ​​the receiving portion in the clamping portion is reduced by radial compression in step a) and is thereby smaller than the cross-sectional area of ​​the end of the ceramic roller. However, outside the clamping portion, the cross-sectional area of ​​the receiving portion remains equal to or greater than the cross-sectional area of ​​the end of the ceramic roller.

[0036] In a further preferred embodiment of the method, the sleeve is compressed in step b) by at least three press backs, each of which extends circumferentially over an angular area of ​​10 to 60 degrees of the outer wall, or axially over at least 80% of the axial portion of the outer wall, or both.

[0037] Preferably, exactly three crimping tools are used. Each crimping tool can exert a radially inward force on the outer wall. The crimping tools are preferably shaped to conform to the outer wall. The outer wall is deformed from a cylindrical shape or the like by the crimping tools, which are preferably evenly distributed around the circumference of the outer wall.

[0038] The sleeve is preferably compressed in step b) by at least three crimping tools, each of which extends circumferentially over an angular area of ​​10 to 60 degrees of the outer wall and axially over at least 80% of the axial length of the outer wall.

[0039] The invention will now be explained in more detail with reference to the drawings, which show particularly preferred embodiments, but to which the invention is not limited. [Brief explanation of the drawings]

[0040] [Figure 1] 1 is a schematic cross-sectional view of a roller hearth furnace having ceramic rollers housed in two sleeves in accordance with the present invention. [Figure 2] FIG. 2 is a schematic enlarged view of a portion of FIG. [Figure 3] FIG. 3 is a cross-sectional view of the sleeve of FIG. 2. [Figure 4] FIG. 4 is a side view of the sleeve of FIGS. 2 and 3. [Figure 5] FIG. 5 is a cross-sectional view of the sleeve of FIGS. 2 to 4. [Figure 6] 10 is a cross-sectional view of a portion of a sleeve before being radially compressed by a crimping tool. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0041] 1 shows a roller hearth furnace 1 with a number of ceramic rollers 2, one of which can be seen. The ceramic roller 2 is connected at both of its ends 5 to a corresponding (only the one shown) drive and accommodation device 10 via a corresponding sleeve 3 according to the invention, over which it is accommodated. In FIG. 1, the part shown enlarged in FIG. 2 is indicated by a dotted line.

[0042] In Figure 2, it can be seen that the end of the ceramic roller 2 is received in a receiving portion 4 of the sleeve 3. The receiving portion 4 is surrounded by an outer wall 6. The receiving portion is shown here in a simplified form with constant inner and outer radii. A gap is depicted between the ceramic roller 2 and the sleeve 3, but this gap is for illustrative purposes only. In reality, the ceramic roller is in contact with at least a portion of the outer wall 6 in the circumferential direction. Figure 2 also shows a drive and receiving device 10.

[0043] FIG. 3 shows a detailed, full-scale cross-sectional view of the sleeve 3 of FIGS. 1 and 2 before it is attached to the ceramic roller 2. In FIG. 3, it can be seen that the receiving part 4 is surrounded by an outer wall 6, which axially comprises a barrel portion 7 and a clamping portion 8 located in the barrel portion. The wall thickness d of the outer wall 6 is smaller in the barrel portion 7 than in the vicinity of the barrel portion 7. The cross-sectional area of ​​the receiving part 4 is smaller in the clamping portion 8 than in the vicinity of the clamping portion 8. However, this difference is so small that it is not visible in the view of FIG. 3. The reduction in the cross-sectional area is achieved by step a) of the method according to the invention. After this, the sleeve 3 is radially compressed in the clamping portion 8, and radially inward forces act on the outer wall 6 at at least three points on the outer wall 6.

[0044] Step b) of the method according to the invention allows the sleeve 3 to be placed on the ceramic roller 2 in order to use it in the roller hearth furnace 1 of Figures 1 and 2. For this purpose, the sleeve 3 is pressed axially onto the end 5 of the ceramic roller 2 and is thus connected to the ceramic roller 2 with a force fit.

[0045] Also, the axial extent of the trunk portion 7 is l T , and the axial extent l of the clamping portion 8 K Furthermore, the axial extent of the receiving portion 4 is l A Shows.

[0046] Furthermore, it can be seen that there is a hexagonal recess 11, via which the sleeve 3 can be positively connected to the drive and receiving device 10.

[0047] Fig. 4 is a side view of the sleeve 3 shown in Fig. 2 and Fig. 3. Fig. 5 is a cross-sectional view of the sleeve 3.

[0048] FIG. 6 is a cross-sectional view of a portion of the sleeve 3 before being radially compressed in step b). By radially compressing the sleeve 3, the sleeve 3 shown in FIGS. 2 to 5 can be obtained. Before being radially compressed, the outer wall 6 has a cylindrical shape. The outer wall 6 is slightly deformed by being radially compressed. R i,1 and R i,2 represent the two distances between the inside of the outer wall 6 and the axis of the outer wall 6 (located outside the detail view of FIG. 6). a represents the distance between the outside of the outer wall 6 and the axis of the outer wall 6 (located outside the detailed view of FIG. 6). In the situation before radial compression shown in the figure, R i,1 =R i,2 The radial compression can be achieved by, among other things, crimping tools 9. The compression is preferably achieved by at least three crimping tools, which are designed like the crimping tool 9 shown in the figure and are evenly distributed around the circumference of the sleeve 3. Due to the radial compression, R i,2 is due to the arrangement of the crimping tool 9, Ri,1 During radial compression, the wall thickness remains unchanged.

[0049] The sleeve 3 allows a particularly secure fit of the ceramic roller 2 in the roller hearth furnace 1, even at high temperatures. To achieve this, the sleeve 3 is reduced in cross section during manufacture at the clamping portion 8. When the sleeve 3 is pressed axially against the end 5 of the ceramic roller 2, the reduced cross section at the clamping portion 8 generates an elastic force that holds the sleeve 3 on the ceramic roller 2. [Explanation of symbols]

[0050] 1. Roller hearth furnace 2 ceramic rollers 3 Sleeve 4 Receiving part 5 End 6. Exterior Wall 7. Torso 8 Tightening part 9 Crimping tool 10. Drive and storage device 11 Hexagonal hole d wall thickness l T Axial spread of the trunk l K Axial spread of the tightened part l A Axial spread of receiving part R i,1 Internal distance before radial compression R i,2 Internal distance before radial compression R a Outer distance before radial compression

Claims

1. A sleeve (3) for mounting a ceramic roller (2) in a roller hearth furnace (1), The sleeve (3) has a receiving portion (4) for one end (5) of the ceramic roller (2), The receiving portion (4) is surrounded by an outer wall (6), The outer wall (6) has, in the axial direction, a body portion (7) and a fastening portion (8) located inside the body portion so as not to protrude beyond the body portion and not to coincide with the body portion; The wall thickness (d) of the outer wall (6) in the trunk portion (7) is smaller than that of the portion adjacent to the trunk portion (7); The cross-sectional area of ​​the receiving portion (4) at the fastening portion (8) is smaller than that of the portion adjacent to the fastening portion (8). sleeve.

2. A sleeve (3) according to claim 1, The wall thickness (d) of the outer wall (6) in the trunk portion (7) is 20 to 60% of the wall thickness (d) of the outer wall (6) in the portion adjacent to the trunk portion (7). sleeve.

3. A sleeve (3) according to any one of claims 1 or 2, The cross-sectional area of ​​the receiving portion (4) in the fastening portion (8) is smaller by 0.03 to 0.3% than that of the portion adjacent to the fastening portion (8). sleeve.

4. A sleeve (3) according to any one of claims 1 to 3, The axial extent of the clamping portion (8) (l Ｋ ) is the axial extent (l) of the body part (7). Ｔ ) is at least 70% of sleeve.

5. A sleeve (3) according to any one of claims 1 to 4, The body portion (7) has an axial extent (l Ａ axial extent (l) in the range of 40 to 80% Ｔ ) sleeve.

6. A set comprising a ceramic roller (2) for a roller hearth furnace (1) and a sleeve (3) for mounting the ceramic roller (2) in the roller hearth furnace (1), The sleeve (3) has a receiving portion (4) for one end (5) of the ceramic roller (2), The receiving portion (4) is surrounded by an outer wall (6), The outer wall (6) has, in the axial direction, a body portion (7) and a fastening portion (8) located inside the body portion so as not to protrude beyond the body portion and not to coincide with the body portion; The wall thickness (d) of the outer wall (6) in the trunk portion (7) is smaller than that of the portion adjacent to the trunk portion (7); the cross-sectional area of ​​the receiving portion (4) is smaller than the cross-sectional area of ​​the ceramic roller (2) at the end (5) only at the clamping portion (8); set.

7. A method for installing a sleeve (3) on a ceramic roller (2) for a roller hearth furnace (1), comprising the steps of: The sleeve (3) is formed to mount the ceramic roller (2) in the roller hearth furnace (1), The sleeve (3) has a receiving portion (4) for one end (5) of the ceramic roller (2), The receiving portion (4) is surrounded by an outer wall (6), The outer wall (6) has a barrel portion (7) in the axial direction, The wall thickness (d) of the outer wall (6) in the trunk portion (7) is smaller than that of the portion adjacent to the trunk portion (7); The method comprises: a) radially compressing the sleeve (3) at a clamping portion (8) located on the barrel portion (7), a step of applying radially inward forces to the outer wall (6) at at least three locations on the outer wall (6); b) pressing the sleeve (3) axially against the end (5) of the ceramic roller (2); A method comprising:

8. 8. The method of claim 7, The sleeve (3) according to any one of claims 1 to 5 is formed after step a). method.

9. The method of claim 8, the cross-sectional area of ​​the receiving portion (4) at the clamping portion (8) is smaller than the cross-sectional area of ​​the end portion (5) of the ceramic roller (2) due to step b); method.

10. The method according to any one of claims 7 to 9, The sleeve (3) is compressed by at least three crimping tools (9) in step b), The crimping tools each include: extending in the circumferential direction over an angular region of 10 to 60 degrees of said outer wall (6); or axially extending over at least 80% of the barrel portion (7) of the outer wall (6), or It's both. method.

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