Abstract
A flanged-shaft apparatus (1) is configured for rotatably supporting a drum (4) in a washing machine having such a flanged-shaft apparatus (1). The flanged-shaft apparatus (1) has a connecting flange (2) configured to be arranged against a drum base (41) of the drum (4) and attached to the drum (4), and a drive shaft (3) arranged in the center of the connecting flange (2) and connected thereto for connection to a drive motor. The connecting flange (2) has a main element (21) formed from a steel sheet and a supporting element (22) formed from a further steel sheet. The main element (21) and the supporting element (22) are arranged one on top of the other along a longitudinal axis (L) of the drive shaft (3).
Claims
1. A flanged-shaft apparatus (1) for rotatably supporting a drum (4) in a washing machine, the flanged shaft comprising: a connecting flange (2) configured to be arranged against a drum base (41) of the drum (4) and to be attached to the drum (4), the connecting flange having a center configured to coincide with an axis of rotation of the drum, and a drive shaft (3) arranged in the center of the connecting flange (2) and connected thereto for connecting the connecting flange to a drive motor, wherein the connecting flange (2) includes a main element (21) formed from a steel sheet and a supporting element (22) formed from a further steel sheet, the main element (21) and the supporting element (22) being arranged offset from one another along a longitudinal axis (L) of the drive shaft (3).
2. The flanged-shaft apparatus (1) according to claim 1, wherein the main element (22) is star-shaped and has at least three arms, each of which extends radially outwards from the drive shaft (3) perpendicularly to the longitudinal axis of the drive shaft (3) and along a respective associated arm axis (a, b, c).
3. The flanged-shaft apparatus (1) according to claim 2, wherein at least one of the arms (2a; 2b; 2c) has a hat-shaped cross section in a cross-sectional plane extending perpendicularly to its arm axis (a, b, c).
4. The flanged-shaft apparatus (1) according to claim 3, wherein the hat-shaped cross section is supplemented by the supporting element (22) to form a box-shaped cross section near the drive shaft (3).
5. The flanged-shaft apparatus (1) according to claim 1, wherein the connecting flange (2) has a further supporting element (23) that is arranged on the supporting element (22) along the longitudinal axis in such a way that the main element (21), the supporting element (22) and the further supporting element (23) form a stack in parallel with the longitudinal axis.
6. The flanged-shaft apparatus (1) according to claim 1, wherein at least two of the drive shaft (3), the main element (21), and the supporting element (22) are soldered or welded together.
7. The flanged-shaft apparatus (1) according to claim 4, wherein a hermetically sealed cavity (7) is formed between the main element (21) and the supporting element (22) by soldering or welding, wherein the cavity (7) extends around the longitudinal axis and is in part delimited by the drive shaft (3).
8. The flanged-shaft apparatus (1) according to claim 1, wherein a sheet thickness of the main element (21) increases along a radial axis towards the longitudinal axis.
9. The flanged-shaft apparatus (1) according to claim 1, wherein the drive shaft (3), the main element (21), and the supporting element (22) form at least one substantially triangular structure in a sectional plane in which the longitudinal axis extends.
10. The flanged-shaft apparatus (1) according to claim 9 when dependent on claim 2, characterized in that the sectional plane in which the triangular structure(s) are formed is defined by the longitudinal axis (L) and one of the arm axes (a; b; c).
11. The flanged-shaft apparatus (1) according to claim 1, wherein the main element (21) and the supporting element (22) are stamped bending elements.
12. A washing machine comprising a tub, a flanged-shaft apparatus (1) according to claim 1, and a drum (4) rotatably held in the tub by the flanged-shaft apparatus (1).
13. The flanged-shaft apparatus (1) according to claim 5, wherein the drive shaft (3), the main element (21), the supporting element (22) and the further supporting element (23) form at least one substantially triangular structure in a sectional plane in which the longitudinal axis extends.
14. The flanged-shaft apparatus (1) according to claim 1, wherein a combined sheet thickness of the main element and the supporting element of the connecting flange (2) increases along a radial axis towards the longitudinal axis.
15. The flanged-shaft apparatus (1) according to claim 5, wherein a total sheet thickness representing a sum of sheet thicknesses of the main element, of the supporting element, and of the further supporting element of the connecting flange (2) increases along a radial axis towards the longitudinal axis.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
(1) In the drawings:
(2) FIG. 1 is a schematic view of a drum having a flanged-shaft apparatus according to a preferred embodiment attached thereto;
(3) FIG. 2 is a perspective view of the side of a flanged-shaft apparatus according to a preferred embodiment facing away from the drum;
(4) FIG. 3 is a perspective view of a flange rear side of the flanged-shaft apparatus from FIG. 2 facing the drum;
(5) FIG. 4 shows the flanged-shaft apparatus from FIGS. 2 and 3 in an exploded view;
(6) FIG. 5 is a sectional view of the flanged-shaft apparatus from FIGS. 2 and 3;
(7) FIG. 6 is a cross-sectional view of the flanged-shaft apparatus from FIG. 5;
(8) FIG. 7 is a cross-sectional view of the flanged-shaft apparatus from FIG. 5 in a cross-sectional plane perpendicular to an arm axis of one of three arms, far from a longitudinal axis;
(9) FIG. 8 is a cross-sectional view of the flanged-shaft apparatus from FIG. 5 in a further cross-sectional plane perpendicular to the same arm axis as in FIG. 7, closer to the longitudinal axis; and
(10) FIG. 9 is a cross-sectional view of the flanged-shaft apparatus from FIG. 5 in a further cross-sectional plane perpendicular to the same arm axis as in FIGS. 7 and 8, along the longitudinal axis.
DETAILED DESCRIPTION OF THE DRAWINGS
(11) FIG. 1 is a schematic view of a drum 4 having a flanged-shaft apparatus 1 attached thereto. The flanged-shaft apparatus 1 is composed of a drive shaft 3 and a connecting flange 2. The drum 4 is cylindrical and has a drum shell 42, a drum base 41 and a drum opening 43 opposite the drum base 41 and not visible in FIG. 1. The connecting flange of the flanged-shaft apparatus 1 indicated in FIG. 1 is star-shaped and has three arms 2a, 2b, 2c. A connecting element 26 is indicated at the outer end of each arm 2a, 2b, 2c. The connecting flange 2 is connected to the drum 4 by means of the connecting elements 26, it being possible for the connecting flange 2 to be connected either to the drum base 41 or preferably additionally to the drum shell 42, for example by means of threaded rods that extend along the entire length of the drum shell 42.
(12) FIG. 2 is a perspective view of the side of a flanged-shaft apparatus 1 according to a preferred embodiment facing away from the drum 4. The drive shaft 3 is cylindrical and extends along a longitudinal axis L. When installed in a washing machine (not shown), the longitudinal axis L is equal to an axis of rotation about which the drum 4 rotates. The star-shaped, three-arm design of the connecting flange 2 is clearly visible in FIG. 2. In this case, the connecting flange 2 is composed of a main element 21, a supporting element 22 and a further supporting element 23. These three elements 21, 22, 23 are stacked along the longitudinal axis L and connected to the drive shaft 3.
(13) In the present embodiment, the main element 21 substantially defines the star-shaped form of the connecting flange 2 and has three arms 2a, 2b, 2c, each of which extends radially outwards from the longitudinal axis L along a corresponding arm axis a, b, c. The three arm axes a, b, c each have an angle of 120° relative to each other in pairs. The supporting element 22 can also be referred to as star-shaped and three-armed, but the three arms are extremely short. As will be explained below, this serves to save material. As a result, the supporting element 22 has more of a hexagonal shape. The element stack or sheet stack is completed by the further supporting element 23, which is circular and has a central hole, that is it has an annular design.
(14) FIG. 3 is a perspective view of a flange rear side 25 of the flanged-shaft apparatus 1 from FIG. 2 facing the drum 4. The flange rear side 25 is formed by a surface of the main element 21. It is convex and fits snugly into a concave cavity of the drum base 41 when attached to the drum 4.
(15) An exploded view of the flanged-shaft apparatus 1 from FIGS. 2 and 3 is shown in FIG. 4. In this case, it can be seen in particular that each of the connecting elements 26 is formed from a hole in the relevant arm 2a, 2b, 2c of the main element 21 and in each case additionally from a small plate that acts as a nut for a threaded rod. In addition, it can be seen in FIG. 4 that all three elements 21, 22, 23 each have an internal hole 210, 220, 230 into which the drive shaft 3 is inserted. It should also be mentioned here that the main element 21 and the supporting element 22 have threefold rotational symmetry about the longitudinal axis L as an axis of symmetry. In contrast, the further supporting element is rotationally symmetrical, likewise about the longitudinal axis L.
(16) The edge of the internal hole 210 of the main element 21 is bent substantially in parallel with the longitudinal axis L to form a sleeve-like projection 211. Likewise, the internal hole 230 of the further supporting element 23 has such a sleeve-like projection 231. These two projections 211, 231 serve to increase the connecting surface between the main element 21 and the drive shaft 3 and between the further supporting element 23 and the drive shaft 3.
(17) FIG. 5 is a sectional view of the flanged-shaft apparatus 1. In this case, the sectional plane is defined by the longitudinal axis L and an arm axis a. The resulting intersection edges are shown as hatched areas. The main element 21, the supporting element 22 and the further supporting element 23 are formed from stamped sheet metal, in particular steel sheets, preferably made of stainless steel.
(18) FIG. 6 is a cross-sectional view of the flanged-shaft apparatus in the same sectional plane as in FIG. 5. In comparison with the sectional view from FIG. 5, only the intersection edges of the different elements with the sectional plane are shown in the cross-sectional view. Furthermore, auxiliary lines are shown in FIG. 6 in order to illustrate the mechanical interaction of the different elements of the flanged-shaft apparatus 1. These are, in particular, two different features that will be explained below with reference to FIG. 6. These features can be used independently in other embodiments, but cooperate in the present embodiment to increase the rigidity of the flanged-shaft apparatus. The first feature is a previously explained increase in a total sheet thickness, which is illustrated on the left-hand side of the drive shaft 3 in FIG. 6. As the second feature, the presence of triangular structures likewise explained above is illustrated in FIG. 6 on the right-hand side of the drive shaft 3.
(19) An arm axis a, indicated by a dashed line in FIG. 6, of the arm 2a of the main element 21, which is visible here in cross section, is divided into three thickness regions a1, a2, a3. The arm axis a, like the other two arm axes b, c, is a radial axis. The first thickness region a1 is the projection of only the region of the connecting flange 2 having only the main element 21 onto the arm axis a. In the second thickness region a2, the supporting element 22 is added, while the further supporting element 23 also has a share in the third thickness region a3. In the case of sheet thicknesses of 2 mm for the main element 21, of 2.25 mm for the supporting element 22 and of 3 mm for the further supporting element 23, the following total sheet thicknesses result in the three thickness regions a1, a2, a3 for the connecting flange 2: In the first thickness region a1, the total sheet thickness is equal to the sheet thickness of the main element, namely also 2 mm. In the second thickness region a2, the sheet thicknesses of the main element 21 and of the supporting element 22 add up to a total sheet thickness of 4.25 mm. In the third thickness region a3, the sheet thicknesses of the main element 21, of the supporting element 22 and of the further supporting element 23 add up to a total sheet thickness of 7.25 mm.
(20) The total thickness of the sheet metal, which increases towards the drive shaft 3, serves to, if possible, introduce the material of the connecting flange 2 where a corresponding force input takes place. The forces acting on the connecting flange 2 due to bending moments are still comparatively low near the connecting element 26 for connection to the drum 4. These forces increase along the arm axis a in the direction of the drive shaft 3. As a result of the three-step increase in the total sheet thickness, the rigidity of the connecting flange 2 correspondingly increases from the outside towards the arm axis 3 in order to cope with the increase in force. It should also be noted that, in this consideration, the portion of the supporting element 22 that extends substantially vertically due to a double bend does not, at its junction to the further supporting element 23, additionally contribute to the determined total sheet thickness for the connecting flange 2, rather it is only the sheet thickness of the steel sheet used during the production of the supporting element 22 that is considered.
(21) The portion of FIG. 6 to the right of the drive shaft 3 serves to illustrate the truss structure. The truss structure is also in part realized on the left-hand side, namely with the triangle formed or enclosed by the supporting element 22, the further supporting element 23 and the drive shaft 3. This triangle can also be seen on the right-hand side because it is annularly arranged around the drive shaft 3 with rotational symmetry. On the right-hand side, this triangle is formed by the connecting points 52, 53 and 54, which are formed between the main element 22 and the drive shaft 3, between the supporting element 22 and the further supporting element 23 and between the further supporting element 23 and the drive shaft 3. A further triangular structure or triangle 5, which is responsible for the distribution of bending loads, is defined by the connecting points 51, 52 and a bend, which bend is formed in the steel sheet of the main element 21 at a position opposite the arm 21 in an extension of the arm axis 2a. The leg of the triangle 5 between the connecting points 51 and 52 has an S-shaped bend in the steel sheet. This bend can be seen more clearly in FIG. 5 because no auxiliary lines obstruct the view of the illustration of the triangle 5 there. However, this bend has little influence on the stiffening effect of the leg between the connecting points 51 and 52 such that the distance between the connecting points 51 and 52 can be considered a substantially rigid strut for the analysis of the force distribution.
(22) The force distribution in the structure shown in FIG. 6 will be explained below: When force is introduced (due to the drum 4, which is not shown here) in the axial direction parallel to the longitudinal axis L on the connecting element 26, i.e. at the outer end of the arm 2a, a bending load is exerted on this arm 2a of the main element 21. This load is transmitted from the main element 21 to the drive shaft 3. The supporting element 22 and the further supporting element 23 serve to optimize rigidity and to relieve the main element 21 and the drive shaft 3, as well as to relieve the connecting points 52, 54 between the connecting flange 2 and the drive shaft 3. The greatest bending loads occur at these connecting points 52, 54.
(23) A framework structure, in particular a truss structure, is constructed by means of the connecting points 51 and 52, as well as with the use of the further supporting element 23 and its connection to the supporting element 22 at the connecting point 53. Upon introduction of the axial force on the connecting element 26 into the main element 21, the bending load is thus transmitted into the supporting element 22 via the connecting point 52 and is supported via the connecting points 53 on the second supporting element 23. As a result, a considerable reduction of the occurring loads can be realized in the connecting points 52 and 54 to the drive shaft 3.
(24) In order to increase the connecting surface with the drive shaft 3, the main element 21 and the further supporting element 23 each have, as explained above in connection with FIG. 4, a sleeve-shaped projection 211, 231 on their internal holes 210, 230, which sleeve-shaped projection annularly surrounds the drive shaft 3. These projections 211, 231 are attached to the drive shaft 3 by means of annular welded seams, in particular by means of laser welding.
(25) The above-described triangle, visible in FIG. 6, consisting of the connecting points 52, 53, 54 is also the cross section of a cavity 7 that is annularly formed around the drive shaft 3. Because of annular welded seams that connect the supporting element 22 to the drive shaft 3 (connecting point 52), the supporting element 22 to the further supporting element 23 (connecting point 54) and the further supporting element 23 to the drive shaft 3 (connecting point 53), the cavity 7 is hermetically sealed such that no moisture can get to the surface region of the drive shaft 3 between the two welded seams at the connecting points 52 and 54 from the tub (not shown in the figures) and cause corrosion.
(26) Each of the three arms 2a, 2b, 2c of the main element 21 has, in a corresponding cross-sectional plane perpendicular to the relevant arm axis a, b, c, a hat-shaped cross section that increases in size in the direction of the longitudinal axis L. The hat-shaped cross section is supplemented closer to the longitudinal axis, namely in the thickness region a2 according to FIG. 6, by means of the supporting element 22 to form a box-shaped cross section. Finally, the further supporting element 23 is added such that a truss structure, as shown on the right-hand side in FIG. 6, is formed on the drive shaft 3 itself. This transformation of the cross section of the arm 2a will be explained with reference to the following FIGS. 7, 8 and 9 and also as representative for the other two arms 2b, 2c.
(27) FIG. 7 is a cross-sectional view of the flanged-shaft apparatus 1 in the cross-sectional plane perpendicular to the arm axis a, far from the longitudinal axis L. The hat-shaped structure can be seen here, which structure is composed of a long side 61, two short sides 62 adjoining thereto and one wall 63 that extends approximately in parallel with the long side 61. The cross-sectional plane of FIG. 7 is, when looking at FIG. 6, approximately midway between the thickness region a2 and the connecting element 26. The hat-shaped profile will flatten towards the connecting element 26, as can be seen, for example, in FIG. 3.
(28) FIG. 8 is a cross-sectional view of the arm 2a in a further cross-sectional plane perpendicular to the arm axis a, but closer to the longitudinal axis, namely in the thickness region a2, directly following the thickness region a1. Here, it can clearly be seen that the hat-shaped cross section is supplemented to form a box-shaped cross section that is composed of the long side 61, the two short sides 62 and an, in this case, flat portion of the supporting element 22.
(29) Finally, FIG. 9 shows a cross-sectional view of the arm 2a in a further cross-sectional plane perpendicular to the arm axis a, but along the longitudinal axis L. As can be seen in FIG. 9, the initially hat-shaped and then box-shaped cross section transitions into a truss structure already known from FIG. 6. In the present case, however, the truss structure is identical on both sides of the drive shaft 3 or the longitudinal axis L. On account of the course of the cross-sectional profile illustrated in FIGS. 7, 8 and 9, the rigidity behavior of the connecting flange 2 is optimized in accordance with an axially increasing bending load by increasing the section modulus towards the drive shaft 3 in the axial direction along the arm axis a through the targeted use of different profile types. This is done starting with a hat profile according to FIG. 7 and continuing to additional bracing in a truss-like profile according to FIG. 9 via a closed box profile according to FIG. 8. In addition, unnecessary material doubling is avoided in the outer region, i.e. far away from the longitudinal axis L.
REFERENCE SIGNS
(30) 1 flanged-shaft apparatus 2 connecting flange 21 main element 2a, 2b, 2c, arms a, b, c arm axes a1, a2, a3 thickness regions along a radial axis 210 internal hole, main element 211 sleeve-shaped projection, main element 22 supporting element 220 internal hole, supporting element 23 further supporting element 230 internal hole, further supporting element 231 sleeve-shaped projection, further supporting element 25 flange rear side 26 connecting element 3 drive shaft L longitudinal axis 4 drum 41 drum base 42 drum shell 43 drum opening 5 triangular structure, triangle 51, 52, 53, 54 connecting points 61 long side 62 short sides 63 wall, hat brim 7 cavity
