Plastic pulley of a washing machine drum

Abstract

The invention relates to the technical field of washing machines, and provides a plastic pulley of a washing machine drum, which solves the problems such as increased noise levels or even belt slippage due to excitation of the natural frequency of a belt during operation caused by unevenness of the circumference of the pulley. The pulley includes a hub, a circumference, a dividing rib, first reinforcing ribs each having a second end extending toward the circumference, second reinforcing ribs, and first filling portions. Every two first reinforcing ribs intersect to constitute a reinforcing rib group. First portions, each of which extending from an intersection to the circumference, of first reinforcing ribs in different reinforcing rib groups have no intersection. A first filling portion is provided between first portions of two first reinforcing ribs in each reinforcing rib group, and in contact with the first portions of the two first reinforcing ribs and the circumference.

Description

[0001] PLASTIC PULLEY OF A WASHING MACHINE DRUM

[0002] TECHNICAL FIELD

[0003] The invention relates to the technical field of household washing machines, in particular to a plastic pulley of a washing machine drum.

[0004] BACKGROUND

[0005] A typical construction of a pulley of a washing machine drum includes a central hub, any number of arms and a circumference. The center hub is mounted on the drive shaft; the circumference is used to receive the drive belt; the arms are used to connect the center hub of the pulley to the circumference, so as to provide structural rigidity.

[0006] At present, in order to reduce the weight of the pulley and resolve the problems involving cost, output, and production process in the manufacturing process of the pulley, the pulley of the washing machine drum is made of a plastic material. When a polymer material with a high fiber content is used to manufacture the pulley, it is easy to cause the phenomenon of "fiber-rich surface" on the outer surface of the circumference of the pulley. This "fiber-rich surface" phenomenon results in fiber orientation perpendicular to the outer surface of the circumference of the pulley, which results in the formation of an uneven surface of the circumference saturated with fibers. Further, this uneven surface leads to the excitation of the belt's natural frequency during operation, resulting in increased noise levels or even belt slippage.

[0007] SUMMARY

[0008] Embodiments of the present invention provide a plastic pulley of a washing machine drum, which may avoid the phenomenon of "fiber-rich surface" on a circumference of the pulley when a fiber-reinforced polymer material is used to produce the pulley, so that the circumference of the pulley has an even and smooth outer surface to prevent problems such as increased noise levels or even belt slippage due to excitation of the natural frequency of a belt received by the pulley during operation, caused by unevenness on the outer surface of the circumference.

[0009] In order to achieve the above purpose, the embodiments of the present invention adopt following technical solutions.

[0010] Embodiments of the present invention provide a plastic pulley of a washing machine drum, including a hub, a circumference, a dividing rib, first reinforcing ribs, second reinforcing ribs and first filling portions.

[0011] The circumference is arranged concentrically with respect to the hub. The dividing rib is arranged concentrically with respect to the circumference to divide the pulley into an inner section and an outer section that are arranged concentrically.

[0012] The first reinforcing ribs are arranged in the outer section; a first end of each first reinforcing rib is connected to the dividing rib, and a second end of each first reinforcing rib extends toward the circumference; every two first reinforcing ribs intersect to form a first intersection and constitute a reinforcing rib group; each first reinforcing rib includes a first portion extending from the first intersection toward the circumference and a second portion extending from the first intersection to the dividing rib, and first portions of first reinforcing ribs in different reinforcing rib groups have no intersection.

[0013] The second reinforcing ribs are arranged in the inner section for connecting the dividing rib to the hub.

[0014] A first filling portion is provided between first portions of two first reinforcing ribs in each reinforcing rib group, and the first filling portion is in contact with the first portions of the two first reinforcing ribs and the circumference.

[0015] In the embodiments of the present invention, the first filling portion is provided between the first portions of the two first reinforcing ribs in each reinforcing rib group, and the first filling portion is in contact with both the first portions of the two first reinforcing ribs and the circumference. In this way, it may be possible to ensure a uniform flow of the melt towards the circumference of the pulley and the consistency of the flow direction of the melt towards the circumference of the pulley, which may facilitate the reduction of the material junctions from different flow directions at the circumference of the pulley, so that the fiber orientation on the outer surface of the formed circumference may be reduced. As a result, the outer surface of the circumference has an even and smooth surface, so that the problems such as increased noise levels or even belt slippage due to unevenness on the outer surface of the circumference may be mitigated.

[0016] In some embodiments, the pulley further includes connecting sections and second filling portions. For two adjacent reinforcing rib groups, second ends of two first reinforcing ribs respectively in different reinforcing rib groups are adjacent and connected by a connecting section, and the connecting section and the circumference have a gap therebetween; a second filling portion is provided in the gap, and the second filling portion is in contact with the connecting section, the circumference and first filling portions provided in each of the two adjacent reinforcing rib groups.

[0017] In some embodiments, the connection section is arranged concentrically with respect to the circumference.

[0018] In some embodiments, the pulley further includes third reinforcing ribs each extending substantially in a radial direction relative to the circumference, and each third reinforcing rib is connected to different first reinforcing ribs.

[0019] In some embodiments, for the two adjacent reinforcing rib groups, second portions of two remaining first reinforcing ribs respectively in different reinforcing rib groups intersect to form a second intersection; one end of a third reinforcing rib is in contact with the connecting section, and another end of the third reinforcing rib is connected to the second intersection.

[0020] In some embodiments, the first filling portion has at least two portions with different thicknesses.

[0021] In some embodiments, a thickness of a portion of the first filling portion proximate to the circumference is greater than a thickness of another portion of the first filling portion proximate to the first intersection.

[0022] In some embodiments, each reinforcing rib group is arranged symmetrically to one of remaining reinforcing rib groups with respect to an axis of symmetry substantially extending in a radial direction of the pulley.

[0023] In some embodiments, the pulley is made of a fiber-reinforced polymer material, and a content of fiber in the fiber-reinforced polymer material is in a range of 35% to 70%.

[0024] In some embodiments, the content of the fiber in the fiber-reinforced polymer material is 50%.

[0025] BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to describe technical solutions in the embodiments of the present invention or in the related art more clearly, accompanying drawings to be used in some embodiments of the present invention or in the related art will be introduced briefly below. However, the accompanying drawings to be described below are merely accompanying drawings of some embodiments of the present disclosure or the related art, and a person of ordinary skill in the art may obtain other drawings according to these drawings. In addition, the accompanying drawings to be described below may be regarded as schematic diagrams, and are not limitations on an actual size of a product, an actual process of a method and actual timings of signals to which the embodiments of the present invention relate.

[0027] FIG. 1 is a schematic structural diagram of a tub assembly included in a washing machine;

[0028] FIG. 2 is a schematic structural diagram of a pulley, in accordance with some embodiments;

[0029] FIG. 3 is a schematic structural diagram of another pulley, in accordance with some embodiments; and

[0030] FIG. 4 is a schematic sectional view of a pulley, in accordance with some embodiments.

[0031] Reference signs:

[0032] 100-Tub assembly; 101-Washing tub; 102-Drum; 103-Drive assembly; 1031-Shaft;

[0033] 1032-Electric motor; 1033-Drive belt; T-Pulley

[0034] I -Pulley; 2-First reinforcing rib; E1 -First end; E2-Second end; 2A-First portion; 2B-Second portion; 20-Reinforcing rib group

[0035] 201 -First reinforcing rib group; 21 -First reinforcing rib; 22-First reinforcing rib

[0036] 202-Second reinforcing rib group; 23-First reinforcing rib; 24-First reinforcing rib

[0037] 203-Third reinforcing rib group; 25-First reinforcing rib; 26-First reinforcing rib

[0038] 204-Fourth reinforcing rib group; 27-First reinforcing rib; 28-First reinforcing rib P1 -First intersection; P2-Second intersection

[0039] 3-Circumference; 4-Hub; 5-Third reinforcing rib; 60-Reigon; 6-First filling portion; 61 -Portion of the first filling portion proximate to the circumference; 62-Portion of the first filling portion proximate to the hub

[0040] 7-Connecting section; 8-Second filling portion; 80-Gap; 9-Dividing rib; 10-Second reinforcing rib

[0041] II-lnner section; 12-Outer section

[0042] X1 -First axis of symmetry; X2-Second axis of symmetry; X3-Third axis of symmetry DETAILED DESCRIPTION

[0043] Some embodiments of the present invention will be described clearly and completely with reference to the accompanying drawings in the embodiments of the present invention. However, the described embodiments are merely some but not all embodiments of the present invention. All other embodiments obtained by a person of ordinary skill in the art based on the embodiments of the present invention shall be included in the protection scope of the present invention.

[0044] Unless the context requires otherwise, the term "comprise" throughout the specification and claims is construed as open and inclusive, i.e., "inclusive, but not limited to". In the description of the specification, the terms such as "one embodiment", "some embodiments", "exemplary embodiment", "example" or "some examples" are intended to indicate that specific features, structures, materials or characteristics related to the embodiment(s) or example(s) are included in at least one embodiment or example of the present disclosure. Schematic representations of the above terms do not necessarily refer to the same embodiment(s) or example(s). In addition, the specific features, structures, materials or characteristics may be included in any one or more embodiments or examples in any suitable manner.

[0045] In the description of the present invention, it will be understood that orientations or positional relationships indicated by the terms such as "center", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", and "outer" are based on orientations or positional relationships shown in the drawings, which are merely to facilitate and simplify the description of the present invention, and are not to indicate or imply that the referred devices or elements must have a particular orientation, or must be constructed or operated in a particular orientation. Therefore, these terms should not be construed as limitations to the present disclosure.

[0046] Hereinafter, the terms such as "first", "second" or "third" are used for descriptive purposes only, and are not to be construed as indicating or implying the relative importance or implicitly indicating the number of indicated technical features. Thus, a feature defined with "first", "second" or "third" may explicitly or implicitly include one or more of the features. In the description of the embodiments of the present invention, the terms "a plurality of", "the plurality of", or "multiple" means two or more unless otherwise specified.

[0047] In the description of the embodiments of the present invention, it will be noted that the terms "mounted", "connected", and "connection" is to be understood broadly. For example, it may be a fixed connection, a detachable connection, or an integral connection; it may be a mechanically connection or electrically connection; or it may be a direct connection or may be an indirect connection through an intermediate medium, and may be an internal communication between two components. Specific meanings of the above terms in the present disclosure may be understood by those skilled in the art according to specific situations.

[0048] As used herein, the terms such as "about", "substantially" or "approximately" include a stated value and an average value within an acceptable range of deviation of a particular value. The acceptable range of deviation is determined by a person of ordinary skill in the art, in consideration of the measurement in question and errors associated with the measurement of a particular quantity (i.e., limitations of the measurement system).

[0049] Exemplary embodiments are described herein with reference to section views and / or plan views as idealized exemplary drawings. In the accompanying drawings, thicknesses of layers and sizes of regions are enlarged for clarity. Thus, variations in shape relative to the accompanying drawings due to, for example, manufacturing technologies and / or tolerances may be envisaged. Therefore, the exemplary embodiments should not be construed as being limited to the shapes of the regions shown herein, but including shape deviations due to, for example, manufacturing. For example, an etched region that is shown in a rectangle generally has a curved feature. Therefore, the regions shown in the accompanying drawings are schematic in nature, and their shapes are not intended to show actual shapes of regions in a device, and are not intended to limit the scope of the exemplary embodiments.

[0050] As shown in FIG. 1 , in general, a washing machine includes a tub assembly 100. The tub assembly 100 includes a washing tub 101 and a drum 102 rotatably arranged in the washing tub 101. Laundry washing in a washing machine is carried out in the drum 102.

[0051] The drum 102 is driven to rotate by the drive assembly 103, and the drive assembly 103 includes: a shaft 1031 fixed to the drum 102 and mounted in bearings, a pulley T mounted on the shaft 1031 , an electric motor 1032, and a drive belt 1033 connected to a drive shaft of the electric motor 1032 and the pulley T. Thus, the drive belt 1033 can transmit the rotation of the electric motor 1032 via the pulley T to the drum 102.

[0052] Generally, a typical construction of the pulley 1 ' includes a central hub, any number of arms and a circumference. The central hub is mounted on the shaft 1031 included in the drive assembly 103, the circumference is used for receiving the drive belt 1033, and the arms are used to connect the central hub to the circumference.

[0053] In order to reduce the weight of the pulley and resolve the problems involving cost, output, and production process in the manufacturing process of the pulley, the pulley of the washing machine drum is generally injection molded using the plastic material. The manufacturing process of the pulley is: stirring the plastic material ( e.g., polymer granules ) at a certain temperature, using a screw, to melt the plastic material completely, and injecting the molten plastic material into a mold cavity under a high pressure. That is, the molten plastic material may flow, start from the center hub of the pulley, towards the circumference along the multiple arms, and after cooling and solidification, the pulley is formed.

[0054] At present, in order to enable the pulley to withstand high mechanical loads, fiber-reinforced polymer materials may be used to produce the pulley. In the manufacturing process of the pulley by using the fiber-reinforced polymer material, the phenomenon of "fiber-rich surface" tends to occur on the outer surface of the circumference of the pulley. During the manufacturing process of the pulley, the molten fiber-reinforced polymer flows from the center to the circumference along the multiple arms, the molten fiber-reinforced polymer from different arms joint at a certain position of the circumference. That is, the molten fiber-reinforced polymer flows in different directions (e.g., opposite directions) and joint at a position, which causes a change in the orientation of the fibers at the junction. For example, the orientation of the fibers tends to be perpendicular to the outer surface of the formed circumference. This change in fiber orientation results in different schrinckage along the outer surface, saturated with fibers, which causes uneveness of the circumference and leads to the excitation of the natural frequency of the belt (i.e. , the drive belt 1033 in FIG. 1 ) during operation, resulting in increased noise levels or even belt slippage.

[0055] In order to solve the above problems, some embodiments of the present invention provide a plastic pulley 1 of a washing machine drum, which is injection molded by the plastic material. In some embodiments, as shown in FIGS. 2 and 3, the pulley 1 includes a hub 4, a circumference 3, a dividing rib 9, a plurality of first reinforcing ribs 2, a plurality of second reinforcing ribs 10, and a plurality of first filling portions 6.

[0056] As shown in FIGS. 2 and 3, the hub 4 is located at the center of the pulley 1 , and the pulley 1 is fastened to the shaft 1031 , included in the drive assembly 103 shown in FIG. 1 , with the hub 4, so that the pulley 1 is mounted on the drum 102. The circumference 3 is arranged concentrically with respect to the hub 4 for receiving the driving belt 1033 shown in FIG. 1 , so that the rotation of the electric motor 1032 is transmitted to the drum 102 via the pulley 1 to make the drum 102 rotate.

[0057] As shown in FIGS. 2 and 3, the dividing rib 9 is substantially in a shape of an annulus and arranged concentrically with respect to the circumference 3, for example, may be arranged at approximately half the radius of the circumference 3, so as to divide the pulley 1 into two concentric sections, i.e. , an inner section 11 and an outer section 12. The plurality of second reinforcing ribs 10 are distributed in the inner section 11 for directly connecting the dividing rib 9 to the hub 4, and the plurality of first reinforcing ribs 2 are distributed in the outer section 12 for directly or indirectly connecting the dividing rib 9 to the circumference 3, so as to provide structural rigidity for the pulley 1.

[0058] As shown in FIGS. 2 and 3, each first reinforcing rib 2 has a first end E1 and a second end E2, the first end E1 is connected to the dividing rib 9, and the second end E2 extends toward the circumference 3.

[0059] In some examples, as shown in FIG. 2, the second end E2 of each first reinforcing rib 2 extends toward the circumference 3 and is in contact with the circumference 3. In some other examples, as shown in FIG. 3, the second end E2 of each first reinforcing rib 2 extends toward the circumference 3 and is not in contact with the circumference 3.

[0060] As shown in FIGS. 2 and 3, every two first reinforcing ribs 2 (e.g., the first reinforcing rib 21 and the first reinforcing rib 22) intersect to form a first intersection P1 , and the two first reinforcing ribs 2 constitute a reinforcing rib group 20. Each first reinforcing rib 2 includes a first portion 2A extending from the first intersection P1 toward the circumference 3 and a second portion 2B extending from the first intersection P1 to the dividing rib 9. In addition, first portions 2A of first reinforcing ribs 2 in different reinforcing rib groups 20 have no intersection.

[0061] It will be noted that, for each first reinforcing rib 2, it intersects with another first reinforcing rib 2 to form a first intersection P1 , the first portion 2A refers to a portion of the first reinforcing rib 2 from the first intersection P1 to the second end E2, and the second portion 2B refers to a portion of the first reinforcing rib 2 from the first intersection P1 to the first end E1 .

[0062] It will be noted that "no intersection" here means that: the first portions 2A of the first reinforcing ribs 2 in different reinforcing rib groups 20 do not intersect during the ends (i.e., the second ends E2) of these first reinforcing ribs 2 extends toward the circumference 3, and the two second ends E2 are not in contact with the circumference 3; or, the first portions 2A of the first reinforcing ribs 2 in different reinforcing rib groups 20 do not intersect during the ends (i.e., the second ends E2) of these first reinforcing ribs 2 extend toward the circumference 3, and the two second ends E2 are all in contact with the circumference 3; for example, the two second ends E2 are in contact with the circumference 3 at a position, or the two second ends E2 are each in contact with the circumference 3 at a different position, but they are not in contact with each other.

[0063] Hereinafter, in order to distinguish different reinforcing rib groups for ease of description, some different reinforcing rib groups are respectively referred to as a first reinforcing rib group, a second reinforcing rib group and a third reinforcing rib group.

[0064] In some examples, as shown in FIGS. 2 and 3, the first portion of the first reinforcing rib 22 in the first reinforcing rib group 201 does not intersect the first portion of the first reinforcing rib 23 in the second reinforcing rib group 202.

[0065] For example, as shown in FIG. 2, the first portion of the first reinforcing rib 22 in the first reinforcing rib group 201 does not intersect the first portion of the first reinforcing rib 23 in the second reinforcing rib group 202; moreover, both the second end E1 of the first reinforcing rib 22 and the second end E2 of the first reinforcing rib 23 are in contact with the circumference 3, and are in contact with each other at a position on the circumference 3.

[0066] For another example, as shown in FIG. 3, the first portion of the first reinforcing rib 22 in the first reinforcing rib group 201 does not intersect the first portion of the first reinforcing rib 23 in the second reinforcing rib group 202, and neither the second end of the first reinforcing rib 22 nor the second end of the first reinforcing rib 23 is in contact with the circumference 3.

[0067] As shown in FIGS. 2 and 3, a first filling portion 6 is provided between the first portions 2A of two first reinforcing ribs 2 in each reinforcing rib group 20, and the first filling portion 6 is in contact with the first portions 2A of the two first reinforcing ribs 2 and the circumference 3.

[0068] In some examples, as shown in FIG. 2, second ends E2 of two first reinforcing ribs 2 in each reinforcing rib group 20 extend toward the circumference 3 and are in contact with the circumference 3. Therefore, first portions 2A of the two first reinforcing ribs 2 and the circumference 3 enclose a closed area 60 substantially in a shape of a triangle, the area 60 is filled with a first filling portion 6, and the first filling portion 6 is in contact with both the first portions 2A of the two first reinforcing ribs 2 and the circumference 3.

[0069] In some other examples, as shown in FIG. 3, second ends E2 of two first reinforcing ribs 2 in each reinforcing rib group 20 extend toward the circumference 3, and neither of them is in contact with the circumference 3. A first filling portion 6 is provided between first portions 2A of the two first reinforcing ribs 2 (for example, an area 60 substantially in a shape of a triangle shown in FIG. 3, formed by the first portions of the two first reinforcing ribs and the circumference, is filled with the first filling portion 6), and the first filling portion 6 extends from the first intersection P1 of the two first reinforcing ribs 2 to the circumference 3. That is, the first filling portion 6 is in contact with both the first portions 2A of the two first reinforcing ribs 2 and the circumference 3.

[0070] In the embodiments of the present invention, the first filling portion is provided between the first portions of the two first reinforcing ribs in each reinforcing rib group, and the first filling portion is in contact with both the first portions of the two first reinforcing ribs and the circumference. In this way, during the injection molding process, the melt of the fiber-reinforced polymer material is able to flow, from the first intersection of the first reinforcing ribs, along directions in which the first portions of the two first reinforcing ribs extend, and an area between the first portions of the two first reinforcing ribs is filled with the melt synchronously, it is possible to ensure a uniform flow of the melt towards an outer ring of the pulley and the consistency of the flow direction of the melt towards the outer ring of the pulley, which facilitates the reduction of the material junctions from different flow directions at the circumference of the pulley, so that the fiber orientation on the outer surface of the formed circumference is reduced. As a result, the outer surface of the circumference has an even and smooth surface, so that the problems such as increased noise levels or even belt slippage due to unevenness on the outer surface of the circumference may be mitigated. In addition, the provision of the first filling between the first portions of the two first reinforcing ribs in each reinforcing rib group may also improve the structural rigidity of the pulley, thereby reducing the radial deformation caused by the belt contact along the pulley.

[0071] In some embodiments, as shown in FIG. 3, the pulley 1 further includes connecting sections 7 and second filling portions 8. For two adjacent reinforcing rib groups 20, second ends E2 of two first reinforcing ribs 20 respectively located in different reinforcing rib groups 20 are adjacent and connected by a connecting section 7, and the connecting section 7 and the circumference 3 have a gap 80 therebetween; a second filling portion 8 is provided in this gap 80, and the second filling portion 8 is in contact with the connecting section 7, the circumference 3, and the first filling portions 6 in each of the two adjacent reinforcing rib groups 20.

[0072] For example, as shown in FIG. 3, for the adjacent first reinforcing rib group 201 and second reinforcing rib group 202, the second end of the first reinforcing rib 22 in the first reinforcing rib group 201 is connected to the second end of the first reinforcing rib 23 in the second reinforcing rib group 202 by a connecting section 7, and there is a gap 80 between the connecting section 7 and the circumference 3; the gap 80 is filled with a second filling portion 8, and the second filling portion 8 is in contact with the connecting section 7 and the circumference 3; moreover, this second filling portion 8 is also in contact with the first filling portion 6 filled between the first reinforcing rib 21 and the first reinforcing rib 22 in the first reinforcing rib group 201 and the first filling portion 6 filled between the first reinforcing rib 23 and the first reinforcing rib 24 in the second reinforcing rib group 202.

[0073] In this way, during the injection molding process, the melt may flow from the first intersection of the two first reinforcing ribs toward the outer ring of the pulley along the extending directions of the two first reinforcing ribs, and the area between the first portions of the two first reinforcing ribs is filled with the melt synchronously. Furthermore, the melt from different flow directions join at a certain position of the connecting section, and after the connecting section is formed, the melt continues to flow from the connecting section toward the outer ring of the pulley, so that the area between the connecting segment and the circumference is filled with the melt. That is to say, the provision of the second filling portion disrupts the direct connection between the first reinforcing ribs and the inner surface of the circumference, and avoids the junctions of the melt from different directions at the circumference. Therefore, it is possible to ensure the uniform flow of the melt towards the outer ring of the pulley along the radial direction of the pulley, so that the undesireable fiber orientation (perpendicular or non-tangent to the outer surface orientation) on the outer surface of the formed circumference is reduced. As a result, the outer surface of the formed circumference is even.

[0074] It will be noted that, in the embodiments of the present invention, the connecting section may extend in the circumferential direction of the circumference, or extend in a certain direction intersecting the extending direction of a first reinforcing rib, which is not limited in the embodiments of the present invention, as long as it satisfies the requirement of being able to connect the second ends of two first reinforcing ribs in different reinforcing rib groups of two adjacent reinforcing rib groups. For example, as shown in FIG. 3, the connecting section 7 is arranged concentrically with respect to the circumference 3, which facilitates the unimpeded flow of the melt toward the circumference.

[0075] In some embodiments, as shown in FIG. 3, the pulley 1 further includes third reinforcing ribs 5. Each third reinforcing rib 5 substantially extends in the radial direction relative to the circumference 3 and is connected to different first reinforcing ribs 2.

[0076] In this way, during the injection molding process, the third reinforcing rib provides an additional flow path for the flow of the melt, thereby ensuring the uniform distribution of the melt during the flow from the center of the pulley toward the outer ring, and avoiding any preferential flow towards the outer ring of the pulley along the first reinforcing rib. That is, it is ensured that the melt may flow towards the outer ring of the pulley uniformly along the directions in which different first reinforcing ribs extend. In addition, the third reinforcing rib may improve the stability and robustness of the pulley.

[0077] In some examples, as shown in FIG. 3, for two adjacent reinforcing rib groups 20, second portions 2B of two first reinforcing ribs 2 respectively in different reinforcing rib groups 20 intersect to form a second intersection P2. On this basis, one end of the third reinforcing rib 5 is in contact with the connecting section 7, and the other end of the third reinforcing rib 5 is connected to the second intersection P2.

[0078] For example, as shown in FIG. 3, for the adjacent first reinforcing rib group 201 and the second reinforcing rib group 202, the second portion of the first reinforcing rib 21 in the first reinforcing rib group 201 and the second portion of the first reinforcing rib 24 in the second reinforcing rib group 202 intersect to form a second intersection P2; one end of the third reinforcing rib 5 is in contact with the connecting segment 7 at the middle of the connecting segment 7, and the other end of the third reinforcing rib 5 is connected to the second intersection P2.

[0079] In this way, during the process of the melt flowing from the center of the pulley towards the outer ring, when flows to the second intersection, the melt continues to flow towards the outer ring of the pulley in more directions, which may further facilitate the uniform distribution of the melt. Moreover, an end of the third reinforcing rib is connected to the second intersection of the second portions of the two first reinforcing ribs, so that the stability and robustness of the pulley structure may be further improved.

[0080] In some embodiments, as shown in FIG. 4, the thickness of the first filling portion 6 is not uniform, so as to adjust the flow velocity of the melt. For example, the first filling portion 6 has at least two portions with different thicknesses.

[0081] For example, as shown in FIG. 4, in the radial direction of the pulley, the first filling portion 6 has a portion 61 proximate to the circumference 3 and another portion 62 proximate to the first intersection P1 with different thicknesses, and the thickness D1 of the portion 61 of the first filling portion 6 proximate to the circumference 3 is greater than the thickness D2 of the portion 62 of the first filling portion 6 proximate to the first intersection P1.

[0082] In the process of injecting the melt, the flow velocity of the melt is controlled by controlling the thickness of the filled area. For example, the melt flows slowly in an area with a small thickness, and flows more easily and can reach the outer ring of the pulley faster in an area with a large thickness, thereby avoiding the flow backlogs and the subsequent material junctions from opposite directions. As a result, it is ensured that the melt may reach the circumference of the pulley uniformly.

[0083] In some embodiments of the present invention, the content of the fiber in the fiber-reinforced polymer material is in a range of 35% to 70%. For example, the content of the fiber may be 35%, 40%, 50%, 65%, 70%, or the like. Preferably, the content of the fiber is 50%.

[0084] The polymer matrix of the fiber-reinforced polymer material may be a high-performance polymer such as polyamide (PA), or may be other polymers such as polypropylene (PP), polyethylene (PE) or acrylonitrile butadiene styrene plastic (ABS). The fiber may be glass fiber, carbon fiber, aramid fiber, or the like.

[0085] In the embodiments of the present invention, the type of the polymer matrix and the type of the fiber in the fiber-reinforced polymer material will not be limited, as long as the pulley made of the fiber-reinforced polymer material can maintain the required properties and characteristics of the pulley during operation.

[0086] For example, the fiber-reinforced polymer material provided by the embodiments of the present invention may include polypropylene with a content of 50% and glass fiber with a content of 50%.

[0087] As another example, the fiber-reinforced polymer material provided by the embodiments of the present invention may include polypropylene with a content of 65% and glass fiber with a content of 35%.

[0088] In the embodiments of the present invention, the pulley is made of the fiber-reinforced polymer material. Due to the presence of fiber, the flow behavior of the melt of the fiber-reinforced polymer material is influenced by the content of the fiber. Specifically, the melt exhibits an enhanced flowability with a low content of the fiber, and the melt exhibits a poor flowability with a high content of the fiber. Therefore, the thicknesses of different portions of the first filling portion provided by the embodiments of the present invention may be determined on the basis of the simulations of the melt, taking into account the properties of the selected fiber-reinforced polymer material, so that the provision of the first filling portion may not only provide radial stiffness for the pulley, but also ensure the uniform flow of the melt towards the circumference during injection molding to minimize the phenomenon of "fiber-rich surface".

[0089] It will be noted that, the thicknesses of other structures (e.g., each reinforcing rib and the second filling portion) of the pulley and the thickness relationship between the structures of the pulley are not limited in the embodiments of the present invention, and can be adjusted based on the simulations of the melt, taking into account the properties of the selected material, as long as the melt can uniformly reach the circumference during the process of injection, and the final formed pulley can withstand the required mechanical loads during operation.

[0090] The distribution of the plurality of first reinforcing ribs and the plurality of second reinforcing ribs included in the pulley provided by the embodiments of the present invention will be described below. It will be noted that the following embodiments and accompanying drawings are only illustrative, and are not limitations on the distribution of the first reinforcing ribs and the second reinforcing ribs included in the pulley provided in the embodiments of the present invention.

[0091] In some embodiments, the pulley 1 includes a plurality of reinforcing rib groups 20. Each reinforcing rib group is arranged symmetrically to one of remaining reinforcing rib groups with respect to an axis of symmetry substantially extending in the radial direction of the pulley 1 , so that the plurality of reinforcing rib groups 20 may uniformly distributed in the outer section 12 of the pulley 1 to ensure the balance of the pulley during operation.

[0092] For example, as shown in FIGS. 2 and 3, the first reinforcing rib group 201 and the second reinforcing rib group 202 are symmetric with respect to an axis of symmetry (in order to distinguish different axes of symmetry, this axis of symmetry will be referred to as a first axis of symmetry X1 below) substantially extending in the radial direction of the pulley 1 . That is, the first reinforcing rib 22 in the first reinforcing rib group 201 and the first reinforcing rib 23 in the second reinforcing rib group 202 are symmetric with respect to the first axis of symmetry X1 , and the first reinforcing rib 21 in the first reinforcing rib group 201 and the first reinforcing rib 24 in the second reinforcing rib group 202 are also symmetric with respect to the first axis of symmetry X1.

[0093] As another example, as shown in FIGS. 2 and 3, the first reinforcing rib group 201 and the third reinforcing rib group 203 are symmetric with respect to an axis of symmetry (in order to distinguish different axes of symmetry, this axis of symmetry will be referred to as a second axis of symmetry X2) substantially extending in the radial direction of the pulley 1 . That is, the first reinforcing rib 22 in the first reinforcing rib group 201 and the first reinforcing rib 26 in the third reinforcing rib group 203 are symmetric with respect to the second axis of symmetry X2, and the first reinforcing rib 21 in the first reinforcing rib group 201 and the first reinforcing rib 25 in the third reinforcing rib group 203 are also symmetric with respect to the second axis of symmetry X2.

[0094] As still another example, as shown in FIGS. 2 and 3, the fourth reinforcing rib group 204 and the third reinforcing rib group 203 are symmetric with respect to an axis of symmetry (in order to distinguish different axes of symmetry, this axis of symmetry will be referred to as a third axis of symmetry X3) substantially extending in the radial direction of the pulley 1. That is, the first reinforcing rib 27 in the fourth reinforcing rib group 204 and the first reinforcing rib 25 in the third reinforcing rib group 203 are symmetric with respect to the third axis of symmetry X3, and the first reinforcing rib 28 in the fourth reinforcing rib group 204 and the first reinforcing rib 26 in the third reinforcing rib group 203 are also symmetric with respect to the third axis of symmetry X3.

[0095] In some embodiments of the present invention, the first reinforcing rib is arc-shaped. For example, a radius of the arc-shaped first reinforcing rib may be approximately equal to or greater than the radius of the pulley. The plurality of first reinforcing ribs are evenly distributed in the outer section to improve the structural stability of the pulley, and reduce the deformation of the circumference of the pulley. Of course, the shape of the first reinforcing rib may vary, which is not limited in the embodiments of the present invention.

[0096] In some examples, as shown in FIGS. 2 and 3, the second reinforcing rib 10 is in a shape of a polygon, and the plurality of second reinforcing ribs 10 form a honeycomb, so that the pulley has high axial and radial stiffness, and the bending deformations of the pulley is reduced. Of course, the shape of the second reinforcing rib may vary, which is not limited in the embodiments of the present invention, as long as the second reinforcing ribs can enable the dividing rib to be connected to the hub to make the pulley can withstand the high mechanical loads.

[0097] In the embodiments of the present invention, the numbers of the first reinforcing ribs and the second reinforcing ribs will be set according to actual needs. The number of the third reinforcing ribs is related to the number of the first reinforcing ribs and the arrangement manner of the first reinforcing ribs. The number of each type of the reinforcing rib will not be limited in the embodiments of the present invention, as long as the formed pulley can withstand the required mechanical loads during operation.

[0098] A person skilled in the art will understand that the scope of disclosure in the present disclosure is not limited to specific embodiments discussed above, and may modify and substitute some elements of the embodiments without departing from the spirits of this invention. The scope of the present invention is limited by the appended claims.

Claims

1. A plastic pulley of a washing machine drum, characterized in that the pulley comprises: a hub; a circumference arranged concentrically with respect to the hub; a dividing rib arranged concentrically with respect to the circumference to divide the pulley into an inner section and an outer section that are arranged concentrically; first reinforcing ribs arranged in the outer section, wherein a first end of each first reinforcing rib is connected to the dividing rib, and a second end of each first reinforcing rib extends toward the circumference; every two first reinforcing ribs intersect to form a first intersection and constitute a reinforcing rib group; each first reinforcing rib includes a first portion extending from the first intersection toward the circumference and a second portion extending from the first intersection to the dividing rib, and first portions of first reinforcing ribs in different reinforcing rib groups have no intersection; and second reinforcing ribs disposed in the inner section for connecting the dividing rib to the hub; and first filling portions, wherein a first filling portion is provided between first portions of two first reinforcing ribs in each reinforcing rib group, and the first filling portion is in contact with the first portions of the two first reinforcing ribs and the circumference.

2. The pulley according to claim 1 , characterized in that the pulley further comprises: connecting sections; wherein for two adjacent reinforcing rib groups, second ends of two first reinforcing ribs respectively in different reinforcing rib groups are adjacent and connected by a connecting section, and the connecting section and the circumference have a gap therebetween; and second filling portions, wherein a second filling portion is provided in the gap, and the second filling portion is in contact with the connecting section, the circumference and first filling portions provided in each of the two adjacent reinforcing rib groups.

3. The pulley according to claim 2, characterized in that the pulley further comprises: third reinforcing ribs each extending substantially in a radial direction relative to the circumference, wherein each third reinforcing rib is connected to different first reinforcing ribs.

4. The pulley according to claim 3, characterized in that for the two adjacent reinforcing rib groups, second portions of two remaining first reinforcing ribs respectivelyin different reinforcing rib groups intersect to form a second intersection; wherein one end of a third reinforcing rib is in contact with the connecting section, and another end of the third reinforcing rib is connected to the second intersection.

5. The pulley according to claim 2, characterized in that the connecting section is arranged concentrically with respect to the circumference.

6. The pulley according to claim 1 , characterized in that, the first filling portion has at least two portions with different thicknesses.

7. The pulley according to claim 6, characterized in that a thickness of a portion of the first filling portion proximate to the circumference is greater than a thickness of another portion of the first filling portion proximate to the first intersection.

8. The pulley according to claim 1 , characterized in that each reinforcing rib group is arranged symmetrically to one of remaining reinforcing rib groups with respect to an axis of symmetry substantially extending in a radial direction of the pulley.

9. The pulley according to any one of claims 1 to 8, characterized in that the pulley is made of a fiber-reinforced polymer material, and a content of fiber in the fiber-reinforced polymer material is in a range of 35% to 70%.

10. The pulley according to claim 9, characterized in that the content of the fiber in the fiber-reinforced polymer material is 50%.

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