A washing machine and method of controlling the washing machine

Abstract

The present invention relates to a washing machine configured such that a cylindrical drum formed by processing a metal plate rotates around a horizontal axis, wherein the washing machine includes a plurality of protrusions that extend long in the front-rear direction on the inner surface of the drum and are spaced apart along the circumferential direction, and the height of the protrusions protruding inward from the drum is 2.0 to 6.0% of the diameter of the drum.

Description

Technology Field

[0001] The present invention relates to a washing machine having a drum that rotates around a horizontal axis, and in particular, to a washing machine in which the height of a protruding structure formed on the inner surface of the drum is less than 40 mm. Background Technology

[0002] Washing machines configured such that a drum into which laundry is fed rotates around a horizontal axis are widely known. For example, the washing machine disclosed in Korean Patent Publication No. 10-2011-0022359 has a lifter positioned on the inner circumference of the drum that scoops up laundry when the drum rotates.

[0003] In washing machines equipped with a lifter on the drum, the laundry is scooped up to a certain height and then dropped by the physical force applied by the lifter, or friction is induced between the lifter and the laundry. Consequently, a certain level of washing power can be secured, and compared to structures without a lifter, this washing power is less affected by the amount of water filled in the drum, the load of laundry, and the drum's rotational speed (RPM).

[0004] Meanwhile, in the case of a drum without a lifter, the centrifugal force induced by the rotation of the drum becomes the power to lift the laundry. In this case, when the rotational speed of the drum exceeds the cloth-sticking speed at which the centrifugal force applied to the laundry equals gravity, the laundry rotates while sticking to the inner surface of the drum. Although there is a variation depending on the diameter of the drum, the cloth-sticking speed is 90 to 110 rpm.

[0005] Meanwhile, when a lifter is installed on the drum, the force of the lifter scooping up the laundry acts in addition to the centrifugal force, so the laundry can rotate while stuck to the drum even when the drum's rotational speed is lower than 90 rpm. Conventional washing machines use a lifter with a height of approximately 40 mm, and in this case, when the drum's rotational speed reaches approximately 55 rpm, the laundry rotates while stuck to the drum.

[0006] In other words, in such conventional washing machines, the drum's rotational speed must be limited to approximately 55 rpm or less to ensure that the laundry is scooped up by the lifter and then falls. However, various factors affect washing performance, including not only the drop of the laundry caused by the lifter but also friction between the drum and the laundry, the impact force exerted by the lifter on the laundry, and the bending of the laundry. In particular, since these factors are closely related to the drum's rotational speed, it is necessary to devise a method that allows the drum to rotate at a higher speed than conventional machines while still inducing a drop of the laundry. The problem to be solved

[0007] The problem that the present invention aims to solve is, first, to provide a washing machine that induces a drop of laundry by the rotation of the drum, and increases the upper limit of the drum rotation speed capable of inducing such flow of laundry compared to conventional methods.

[0008] Second, the present invention provides a washing machine in which a protrusion for scooping up laundry is formed on the inner surface of the drum, and the height of the protrusion is appropriately designed so that even if the rotational speed of the drum is 60 rpm or more, the laundry does not stick to the drum and can flow within the drum. means of solving the problem

[0009] The present invention relates to a washing machine configured such that a cylindrical drum into which a bag is fed rotates around a horizontal axis. A plurality of protrusions are provided on the inner surface of the drum. The protrusions extend long in the front-rear direction on the inner surface and are spaced apart along the circumferential direction of the drum.

[0010] The height of the protrusion protruding inwardly into the drum is 2.0 to 6.0% of the diameter of the drum. Alternatively, the protrusion protrudes inwardly into the drum to a height of 10 to 30 mm.

[0011] On the inner surface of the drum, between an adjacent pair of protrusions arbitrarily selected from the plurality of protrusions, there is no protrusion structure higher than any one of the plurality of protrusions.

[0012] The drum may further include a plurality of embossings of a protruding structure formed lower than any of the plurality of protrusions on the inner surface. On the inner surface of the drum, between an adjacent pair of protrusions arbitrarily selected from the plurality of protrusions, no protruding structure other than at least one of the plurality of embossings may exist. The height of the embossing may be 5 mm or less.

[0013] Between an arbitrarily selected adjacent pair of protrusions among the plurality of protrusions, there is no protruding structure on the inner surface of the drum, or only at least one of the plurality of embossings exists.

[0014] The above protrusion may include a first side portion that forms a positive first angle with the inner surface at a first point on the inner surface of the drum when viewed from the front, and a second side portion that forms a negative second angle with the inner surface at a second point on the inner surface spaced circumferentially from the first point when viewed from the front. At least one of the first angle and the second angle may be 17.5 degrees or less.

[0015] The length from the front end to the rear end of the above-mentioned protrusion may be 50 to 100% of the length of the drum. The drum may have a flat front band portion and a rear band portion formed at the front end and rear end, respectively, and the above-mentioned protrusion may be positioned between the front band portion and the rear band portion.

[0016] The above protrusion may be formed integrally with the drum. The drum may be made by processing a stainless steel metal plate and may have a thickness of 0.4 to 0.6 mm.

[0017] Alternatively, the above protrusion may be made of synthetic resin and combined with the drum.

[0018] The diameter of the drum may be 484 mm, and the height of the protrusion protruding inwardly into the drum may be 10.0 to 30.0 mm.

[0019] The diameter of the drum may be 515 mm, and the height of the protrusion protruding inwardly into the drum may be 10.6 to 30.9 mm.

[0020] The diameter of the drum may be 575 mm, and the height of the protrusion protruding inwardly into the drum may be 11.8 to 34.5 mm.

[0021] The diameter of the drum may be 590 mm, and the height of the protrusion protruding inwardly into the drum may be 12.1 to 35.4 mm.

[0022] The control method of the washing machine of the present invention controls the drum to rotate continuously in one direction at least once at a speed set between 60 and 90 rpm so that the foam is scooped up to a predetermined height by the protrusion and then dropped at least once. Effects of the invention

[0023] First, the washing machine of the present invention has the effect of improving washing power because, even when the drum is rotated at a higher speed than conventional ones, the fabric does not stick to the drum and can flow within the drum.

[0024] In particular, even if the drum's rotational speed is 60 rpm or higher, the laundry does not stick to the drum but flows within the drum, thereby having the effect of increasing the laundry attachment speed by approximately 18% compared to conventional methods.

[0025] In addition, since the foam flows within the drum even while the drum is rotating at a higher speed compared to conventional methods, the frictional force between the foam and the drum increases, thereby enhancing the rubbing effect. Brief explanation of the drawing

[0026] FIG. 1 is a side cross-sectional view of a washing machine according to one embodiment of the present invention. Figure 2 schematically illustrates a cross-section of the washing tub shown in Figure 1. Figure 3 schematically illustrates a longitudinal section of the washing tub shown in Figure 1. Figure 4 is a cross-sectional view taken along IV-IV of Figure 3. Figure 5 is a graph showing the fabrication speed according to the height of the protrusion. Figure 6 is a reference drawing used to explain the correlation between the height of the protrusion and the side angle. Figure 7 illustrates the flow of foam according to the rotational speed of the drum. Specific details for implementing the invention

[0027] The advantages and features of the present invention and the methods for achieving them will become clear by referring to the embodiments described below in detail together with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below but may be implemented in various different forms. These embodiments are provided merely to ensure that the disclosure of the present invention is complete and to fully inform those skilled in the art of the scope of the invention, and the present invention is defined only by the scope of the claims. Throughout the specification, the same reference numerals refer to the same components.

[0028] FIG. 1 is a side cross-sectional view of a washing machine according to an embodiment of the present invention. Referring to FIG. 1, a washing machine according to an embodiment of the present invention includes a casing (1) forming an exterior, a water reservoir (3) disposed within the casing (1) and storing washing water, a washing tub (4) installed to be rotatable within the water reservoir (3) and into which laundry is fed, and a motor (9) for rotating the washing tub (4).

[0029] The washing tub (4) includes a front cover (41) having an opening formed for the entry and exit of laundry, a cylindrical drum (42) positioned approximately horizontally with its front end connected to the front cover (41), and a rear cover (43) connected to the rear end of the drum (42). The rotational shaft of the motor (9) can pass through the rear wall of the water tank (3) and be connected to the rear cover (43). A through hole may be formed in the drum (42) so that water can be exchanged between the washing tub (4) and the tub (3).

[0030] The washing tub (4) rotates around a horizontal axis. Here, "horizontal" does not mean geometric horizontal in the strict sense, but rather refers to a case where, even when tilted at a certain angle relative to the horizontal as shown in FIG. 1, it is closer to horizontal than vertical, so it is said that the washing tub (4) rotates around a horizontal axis.

[0031] Additionally, the washing tub (4) includes a plurality of protrusions (20) provided on the inner surface of the drum (42). A plurality of protrusions (20) are extended in the front-rear direction on the inner surface of the drum (42), and these protrusions (20) are spaced apart along the circumferential direction and, preferably, are arranged at a constant angle (equidistant angle) with respect to the center (O) of the drum (42).

[0032] Among the multiple protrusions (20), between an adjacent pair of protrusions (20) selected arbitrarily (or randomly), there is no protruding structure higher than any one of the multiple protrusions (20). In other words, no matter how the adjacent pair of protrusions (20) are selected, there is no structure between them that protrudes higher than the protrusions (20).

[0033] A plurality of embossings (425) may be provided on the inner surface of the drum (42). The embossings (425) are protruding structures formed on the inner surface, and the height of the protrusion into the drum (42) is lower than that of any of the plurality of protrusions (20). On the inner surface of the drum (42), between an adjacent pair of protrusions selected from the plurality of protrusions (20), no protruding structure other than at least one of the plurality of embossings (425) exists.

[0034] The embossing (425) may be formed integrally on the drum (42), and the multiple embossings (425) do not need to have a constant size and / or height, and as shown in FIG. 3, multiple embossings (425) may be formed such that their size gradually increases or decreases along the length of the drum (42). The height of the embossing (425) is 5 mm or less.

[0035] Meanwhile, the drum (42) is made by processing a stainless steel metal plate and may have a thickness of 0.4 to 0.6 mm. A cylindrical drum (42) can be formed by rolling a rectangular metal plate into a circle and joining both ends together (e.g., welding). The metal plate is preferably of the STS430 series, but is not necessarily limited thereto.

[0036] A laundry inlet is formed on the front of the casing (1), and a door (2) for opening and closing the laundry inlet is rotatably provided on the casing (1). A water supply valve (5), a water supply pipe (5), and a water supply hose (8) may be installed inside the casing (1). When the water supply valve (5) is opened and water is supplied, the laundry water passing through the water supply pipe (5) is mixed with detergent in the dispenser (14) and then supplied to the reservoir (3) through the water supply hose (8).

[0037] The input port of the pump (11) is connected to the water tank (3) by the discharge hose (10), and the discharge port of the pump (11) is connected to the drain pipe (12). Water discharged from the water tank (3) through the discharge hose (10) is pumped by the pump (11), flows along the drain pipe (12), and then is discharged outside the washing machine.

[0038] FIG. 7 illustrates the flow of the poultry according to the rotational speed of the drum. Refer to FIG. 7 below. During the process of the drum (42) rotating, the forces acting on the poultry introduced into the drum (42) may include centrifugal force (Fc) induced by the rotation of the drum (42), gravity (Fg), and lifting force (Fn) applied from the protrusion (20).

[0039] As illustrated in FIG. 7(a), when the drum (42) is rotated at a low speed, the centrifugal force (Fc) is relatively small, so the gun is scooped up to a certain height by the protrusion (20), and when the centrifugal force (Fc) and the supporting force (Fn) are unable to withstand gravity (Fg), the gun separates from the protrusion (20) and falls. This flow of the gun is defined as rolling motion.

[0040] FIG. 7(b) shows a state where the rotational speed of the drum (42) is greater than that of FIG. 7(a), and the gun rises to a higher position and then falls. In particular, the position where the gun falls is at a rotational angle of 90 degrees or more from the lowest point of the drum, and such flow of the gun is hereinafter defined as tubling motion.

[0041] As the rotational speed of the drum (42) increases further, the shell will eventually rotate while adhering to the drum (42) without falling even at the highest point of the drum (42), as shown in (c) of FIG. 7. The minimum rotational speed of the drum (42) that can induce a shell attachment in the form of FIG. 7 (c) is defined below as the shell attachment speed (Vf).

[0042] In the case where there is no protrusion (20) on the drum (42), the supporting force (Fn) is eliminated, so the forces acting on the gun are only the centrifugal force (Fc) and gravity (Fg). In this case, the gun emplacement speed (vf) can be obtained from an equilibrium equation in which the centrifugal force and gravity are equivalent. Since the mass of the gun is canceled out on both sides of the above equilibrium equation, the gun emplacement speed (Vf) is independent of the mass of the gun and is dependent on the diameter of the drum, so it is a fixed value that can be obtained if the diameter of the drum is known.

[0043] However, when a protrusion (20) is formed on the drum (42), the support force (Fn) acts more, so the fabric attachment speed (Vf) is generally lower than when the protrusion (20) is not applied. The fabric attachment speed (Vf) at this time will vary depending on the structure of the protrusion (20), but in a conventional washing machine where the diameter of the drum (42) is 24 to 27 inches and the height of the lifter (protrusion) is 40 mm or more, the fabric attachment speed (Vf) is approximately 55 rpm or less.

[0044] The washing power is determined by various factors such as the bending, friction, and drop of the fabric, and these factors are closely related to the rotational speed of the drum (42). In particular, the drop of the fabric or relative motion (or flow within the drum) with respect to the drum is induced, such as rolling or tumbling motion, and the higher the rotational speed of the drum (42), the more advantageous it is for strengthening the washing power.

[0045] In this regard, it is necessary to devise a method to increase the fabric attachment speed (Vf) while rotating the drum (42) at a higher speed than in the past, and the present invention reduces the support force (Fn) by lowering the height (h, i.e., the height protruding inwardly from the drum (42)) of the protrusion (20) compared to the past. At this time, the height (h) of the protrusion (20) is 2.0 to 6.0% of the diameter (D) of the drum (42) and is approximately 10 to 30 mm in absolute value.

[0046] A control method for a washing machine according to one embodiment of the present invention can implement rolling or tumbling motions while rotating the drum (42) at a higher speed than conventional methods.

[0047] Specifically, when the protrusion height of the protrusion (20) is 2.0 to 6.0% of the diameter of the drum (42), the drum (42) is rotated continuously in one direction at least once at a speed set between 60 and 90 rpm, thereby allowing the foam inside the drum (42) to be scooped up to a predetermined height by the protrusion (20) and then dropped at least once.

[0048] The above-described speed may be a speed that induces rolling motion, and at this time, the gun inside the drum (42) rises from the lowest point of the drum (42) to an angle of 90 degrees or less in the direction of rotation of the drum (42) and then falls.

[0049] Alternatively, the above-described speed may be a speed that induces a tumbling motion. At this time, the gun inside the drum (42) rises from the lowest point of the drum (42) to an angle of 90 degrees or more and 180 degrees or less in the rotational direction of the drum (42) and then falls.

[0050] A control unit (not shown) for controlling the rotation of the motor (9) may be provided, and the rotation of the drum (42) may be achieved by controlling the speed of the motor (9) by the control unit.

[0051] FIG. 2 schematically illustrates a cross-sectional view of the washing tub shown in FIG. 1. FIG. 3 schematically illustrates a longitudinal section of the washing tub shown in FIG. 1. FIG. 4 is a cross-sectional view taken along IV-IV of FIG. 3. Refer to FIG. 2 to FIG. 4 below.

[0052] When viewed from the front of the drum (42), the protrusions (20) are shaped such that their length in the longitudinal direction (or front-to-back direction) of the drum (42) is longer than their width in the circumferential direction of the drum (42). These protrusions (20) are arranged symmetrically with respect to the center of the drum (42), and in the embodiment, three protrusions (20) are arranged at an equal angle of 120 degrees with respect to the center of the drum (42), but they are not necessarily limited to this.

[0053] The protrusion (20) can be formed integrally with the drum (42). For example, the protrusion (20) can be formed by plastically processing a metal plate. However, it is not limited thereto, and depending on the embodiment, the protrusion (20) can be formed separately from the drum (42) and then joined to the drum (42). In particular, in the latter case, the protrusion (20) can be made of synthetic resin.

[0054] Meanwhile, in order to widen the contact area between the protrusion (20) and the shell (or the area where the protrusion (20) applies support force (Fn) to the shell) so that the action of scooping up the shell is performed smoothly, the length of the protrusion (20) must be appropriate. In this regard, the present invention proposes that the length (L1) from the front end to the rear end of the protrusion (20) is 50 to 100% of the length (L0) of the drum (42). In particular, even when the length (L1) of the protrusion (20) is close to 50% of the length (L0) of the drum (42), it is preferable to install the protrusion (20) such that the front end of the protrusion (20) is positioned at a location spaced rearward from the front end of the drum (42) so that the protrusion (20) can be positioned to encompass both the front and rear of the drum (42).

[0055] Specifically, the drum (42) has a flat front band portion (42a) and a rear band portion (42b) formed at the front and rear ends, respectively, and the protrusion (20) can be positioned between the front band portion (42a) and the rear band portion (42b).

[0056] Meanwhile, referring to FIG. 4, the protrusion (20) may include a first side portion (21) that forms a positive first angle (+θ) with the inner surface at a first point (P1) on the inner surface of the drum (42) when viewed from the front, and a second side portion (22) that forms a negative second angle (-θ) with the inner surface at a second point (P2) spaced circumferentially from the first point (P1) on the inner surface. Herein, at least one of the first angle and the second angle is 17.5 degrees or less. Hereinafter, the angle θ is defined as the side angle.

[0057] In the embodiment, the first side portion (21) and the second side portion (22) are symmetrical, and the first angle and the second angle have the same size, but are not necessarily limited thereto.

[0058] FIG. 5 is a graph showing the fabric attachment speed (Vf) according to the height of the protrusion. FIG. 6 is a reference drawing used to explain the correlation between the height of the protrusion and the side angle. First, FIG. 5 shows that, as previously mentioned, the fabric attachment speed (Vf) decreases as the height (h) of the protrusion (20) increases. However, when the height (h) of the protrusion (20) is 5mm or less, the fabric attachment speed (Vf) is high, so it seems that the washing performance would be good, but in reality, this is not the case.

[0059] When the height (h) of the protrusion (20) is 5mm or less, the supporting force (Fn) of the protrusion (20) is too small, and when it does not reach the fabric attachment speed (Vf) of the drum (42), the fabric rolls almost in place or moves only up and down within a very small rotation angle range, and then suddenly starts to stick to the drum (42) when it reaches the fabric attachment speed (Vf). This type of fabric movement is exacerbated as the amount of fabric decreases, and the washing power is poor because the drop or bending of the fabric is not smoothly induced. For this reason, the height (h) of the protrusion (20) must be at least greater than 5mm, and preferably 10mm or more.

[0060] Also, it is preferable that the height (h) of the protrusion (20) be 30 mm or less, and in this case, the fabrication speed (Vf) is approximately 65 rpm or more, so an increase in fabrication speed of approximately 18% can be expected compared to 55 rpm when the height is 40 mm.

[0061] The preferred values ​​for the lower limit (LSL) and upper limit (USL) of the height (h) of the protrusion (20) for each diameter (D) of the drum (42) are as follows. Here, the diameter of the drum (42) may be any of the inner diameter, outer diameter, or intermediate value between the inner diameter and the outer diameter of the drum (42).

[0062] Drum diameter (D(mm)) LSL(mm) USL(mm) 484 10.0 30.0 515 10.6 30.9 575 11.8 34.5 590 12.1 35.4

[0063] Meanwhile, referring to FIG. 6, it can be seen that in the case of area A, where the height (h) of the protrusion (20) is less than 5mm and the side angle (θ) is less than 17.5 degrees, rolling or tumbling of the fabric cannot be induced. Therefore, it is preferable that the side angle (θ) be at least 17.5mm so that rolling or tumbling can be induced even when the height (h) of the protrusion (20) is 5mm. Area B shown in FIG. 6 indicates an area where the height (h) of the protrusion (20) is 5mm or more and the side angle (θ) is 17.5 or more, and in this area, it is possible to induce rolling or tumbling motion of the fabric. However, the height of the protrusion (20) that can further enhance washing performance due to such motion is preferably 10mm or more.

[0064] Meanwhile, the curve shown as a dotted line in Fig. 6 connects the threshold values ​​of the side angle (θ) that can induce rolling or tumbling.

[0066] Meanwhile, the control method for a laundry processing device according to an embodiment of the present invention can be implemented as a processor-readable code on a processor-readable recording medium. A processor-readable recording medium includes all types of recording devices in which data that can be read by a processor is stored. Examples of processor-readable recording media include ROM, RAM, CD-ROM, magnetic tape, floppy disk, optical data storage device, etc., and also include implementation in the form of a carrier wave, such as transmission via the Internet. Furthermore, the processor-readable recording medium may be distributed across networked computer systems, so that the processor-readable code can be stored and executed in a distributed manner.

[0068] Although preferred embodiments of the present invention have been illustrated and described above, the present invention is not limited to the specific embodiments described above. Various modifications are possible by those skilled in the art without departing from the essence of the invention as claimed in the patent claims, and such modifications should not be understood individually from the technical spirit or perspective of the present invention.

Claims

Claim 1 A casing; a water reservoir disposed within the casing and storing washing water; a washing tub disposed within the water reservoir and accommodating laundry; wherein the washing tub comprises a cylindrical drum, a front cover coupled to the front end of the drum, and a rear cover coupled to the rear end of the drum; and a motor for rotating the washing tub. A washing machine comprising a plurality of lifters that protrude from the inner surface of the drum, extend in the front-rear direction, and are spaced apart along the circumferential direction of the drum, wherein the lifters have a height of 2.0% to 6.0% of the diameter of the drum, wherein the lifters extend in the front-rear direction of the drum and include a first side protruding from a first point on the inner surface of the drum and a second side protruding from a second point on the inner surface of the drum, wherein the space between the first side and the second side forms the upper portion of the lifters, and at least one of the angle formed by the tangent of the inner surface of the drum at the first point and the first side and the angle formed by the tangent of the inner surface of the drum at the second point and the second side is 17.5 degrees or less, and wherein the lifters allow laundry contained in the washing tub to be lifted by the lifters and fall without sticking to the washing tub when the washing tub rotates continuously in one direction at a speed between 60 rpm and 90 rpm. Claim 2 A washing machine according to claim 1, wherein the drum further comprises a plurality of embossings formed lower than any of the plurality of lifters on the inner surface, and the height of the embossing is less than 2.0% of the diameter of the drum. Claim 3 A washing machine according to claim 1, wherein the length from the front end to the rear end of the lifter is 50 to 100% of the length of the drum. Claim 4 In claim 3, the drum has a flat front band portion and a rear band portion formed at the front and rear ends, respectively, and the lifter is a washing machine disposed between the front band portion and the rear band portion. Claim 5 A washing machine according to claim 1, wherein the lifter is formed integrally with the drum, and the drum is made of a processed stainless steel metal plate with a thickness of 0.4 to 0.6 mm. Claim 6 A washing machine according to claim 1, wherein the height of the lifter is 5 to 30 mm into the inner side of the drum. Claim 7 delete Claim 8 A casing; a water reservoir disposed within the casing and storing washing water; a washing tub disposed within the water reservoir and accommodating laundry; wherein the washing tub comprises a cylindrical drum, a front cover coupled to the front end of the drum, and a rear cover coupled to the rear end of the drum; and a motor for rotating the washing tub. A washing machine comprising a plurality of lifters that protrude from the inner surface of the drum, extend in the front-rear direction, and are spaced apart along the circumferential direction of the drum, wherein the lifters have a height of 5 to 30 mm from the inner surface of the drum, and the lifters extend in the front-rear direction of the drum and include a first side protruding from a first point on the inner surface of the drum and a second side protruding from a second point on the inner surface of the drum, wherein the space between the first side and the second side forms the upper portion of the lifters, and at least one of the angle formed by the tangent of the inner surface of the drum at the first point and the first side and the angle formed by the tangent of the inner surface of the drum at the second point and the second side is 17.5 degrees or less, and wherein the lifters allow laundry contained in the washing tub to be lifted by the lifters and fall without sticking to the washing tub when the washing tub rotates continuously in one direction at a speed between 60 rpm and 90 rpm.

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