Pulley assembly for transferring driving force of laundry dryer

Abstract

The pulley assembly for transferring a driving force of a laundry dryer for drying the laundry according to the present invention comprises a pulley 50 which is coupled to a distal end of a rotation shaft 41 of a driving motor 40 for driving a drum 20 of a laundry dryer, and in which a driving force transmission belt 30 for transferring a rotational force of the driving motor 40 to the drum 20 is hung; and a pulley guide 60 which is coupled to the rotation shaft 41 and installed at one side of the pulley 50; wherein the pulley guide 60 comprises a rotation shaft fitting hole 61A formed through an inner sleeve 61 in the center; and an outer cover 62 having an inclined surface 62A integrally formed in the outer circumference of the inner sleeve 61 at regular intervals, and wherein a separation preventing annular protrusion 62B is protrudingly formed in the circumference of the inclined surface 62A of the outer cover 62.

Description

PULLEY ASSEMBLY FOR TRANSFERRING DRIVING FORCE OF LAUNDRY DRYER

[0001] The present invention relates to a pulley assembly for transferring a driving force of a laundry dryer for drying the laundry. More specifically, the present invention relates to a pulley assembly for transferring a driving force of a laundry dryer capable of preventing a driving force transmission belt from being separated from a pulley guide fixed at a rotation shaft when the rotation shaft rotates by the operation of a driving motor, thereby improving the performance of the laundry dryer.

[0002] In general, a dryer for drying the laundry is a device allowing hot air generated by a heater to be forcibly circulated inside a drum, thereby drying the moisture contained in the laundry inside the drum.

[0003] As disclosed in Korean Patent Laid-Open No. 10-2013-0083670, a dryer is provided with a safety cover in an upper part of the main body forming the appearance of the dryer, has a door for storing or withdrawing the laundry mounted on one side surface inside the main body, and comprises a drum rotatably installed inside the main body so that an object to be dried can be dried therein, wherein the drum is rotatably supported in the main body by a supporter in the front and the back. The drum has a cylindrical shape, and is connected to a driving motor provided in a lower part of the dryer by a driving force transmission belt to receive a rotational force. The driving motor is provided with a pulley at one side thereof. The driving force transmission belt surrounds the drum while being engaged with the pulley, and the driving force transmission belt transfers the rotational force of the pulley to the drum to rotate the drum.

[0004] According to the prior art, the pulley with which the driving force transmission belt is engaged for rotating the drum has a hub in the center of the main body of the pulley where the driving force transmission belt is hung in the rotation shaft of the driving motor, forms a locking edge higher than the hub at both ends of the hub, and couples a screw thread formed in a circumferential surface of the inner space of the main body of the pulley to a screw thread formed in the rotation shaft.

[0005] The hub of the conventional pulley rotates the drum by the driving force transmission belt while the driving force transmission belt is engaged therewith, by which the pulley rotates together with the rotation shaft rotating when the driving motor operates. In the case of increasing or decreasing the number of rotation per minute of the driving motor according to the control program for rotating the drum, the driving force transmission belt may move to the left and right by the vibration of the drum when the drum rotates since the driving force transmission belt engaged with the hub of the rotating pulley is hung in the hub. By this movement, the driving force transmission belt may be separated from the hub of the pulley, which makes the rotation of the drum inconstant, resulting in the degradation of the reliability of the dryer.

[0006] In order to solve said problem, Korean Patent No. 10-2164515 entitled 'pulley assembly for transferring driving force of clothes dryer' provides the driving force transmission by the driving force transmission belt in a safe state within the hub of the pulley, such that the driving force transmission belt returns to the center of the hub while sliding by the outer inclined surface formed in the pulley guide when the driving force transmission belt hung in the hub in the center of the main body of the pulley is separated from the hub upon rotation of the rotation shaft and moves to the pulley guide. Meanwhile, according to this structure, the driving force transmission belt may not return to the hub while being hung on the inclined surface, which may not secure the stable drive of the drum.

[0007] Accordingly, the present invention suggests a novel type of pulley assembly for transferring a driving force of a laundry dryer which improves the structure of a pulley guide and thus facilitates more stable driving.

[0008] It is an object of the present invention to apply a novel separation preventing structure of a driving force transmission belt to a pulley guide installed at one side of a pulley coupled to a rotation shaft of a driving motor so that the driving force can be transferred in a state where the driving force transmission belt is stably mounted on a hub.

[0009] The above and other inherent objects of the present invention may all be easily achieved by the description of the present invention described below.

[0010] The pulley assembly for transferring a driving force of a laundry dryer according to the present invention comprises: a pulley 50 which is coupled to a distal end of a rotation shaft 41 of a driving motor 40 for driving a drum 20 of a laundry dryer, and in which a driving force transmission belt 30 for transferring a rotational force of the driving motor 40 to the drum 20 is hung; and a pulley guide 60 which is coupled to the rotation shaft 41 and installed at one side of the pulley 50; wherein the pulley guide 60 comprises: a rotation shaft fitting hole 61A formed through an inner sleeve 61 in the center; and an outer cover 62 having an inclined surface 62A integrally formed in the outer circumference of the inner sleeve 61 at regular intervals, and wherein a separation preventing annular protrusion 62B is protrudingly formed in the circumference of the inclined surface 62A of the outer cover 62.

[0011] In the present invention, preferably, the separation preventing annular protrusion 62B has a semielliptical cross section or a trapezoidal cross section with both upper ends curved.

[0012] In the present invention, preferably, the separation preventing annular protrusion 62B is a screw thread formed in the circumference of the inclined surface 62A.

[0013] In the present invention, preferably, the separation preventing annular protrusion 62B is formed as a screw thread having a semielliptical cross section or a trapezoidal cross section with both upper ends curved.

[0014] In the present invention, preferably, the outer cover 62 forms the inclined surface 62A which becomes higher as it goes from a first locking ring frame 53 of a pulley body 51, and the outer circumference of the first locking ring frame 53 and the inclined surface 62A form a continuous inclined surface.

[0015] The present invention protrudingly forms an annular protrusion for preventing separation of a driving force transmission belt in an inclined surface of a pulley guide installed at one side of a pulley coupled to a rotation shaft of a driving motor to inhibit movement of the driving force transmission belt which moves along the inclined surface by the separation preventing annular protrusion when the driving force transmission belt engaged with a hub of the pulley is separated upon rotation of the rotation shaft, or returns the driving force transmission belt separated above the inclined surface to the pulley by a screw thread that the pulley guide has when the pulley guide rotates to rapidly and stably mount the driving force transmission belt on the pulley, thereby avoiding the problem caused by the separation of the driving force transmission belt when the dyer operates and improving the reliability of the dryer.

[0016] Fig. 1 is a perspective view illustrating a dryer in which a pulley assembly for transferring a driving force according to the present invention is installed;

[0017] Fig. 2 is an enlarged perspective view illustrating a state where the pulley assembly in Fig. 1 is installed;

[0018] Fig. 3 is an exploded perspective view illustrating a driving motor and a pulley assembly for transferring a driving force of a dryer according to the present invention;

[0019] Fig. 4 is a cross-sectional view illustrating a driving motor and a pulley assembly for transferring a driving force of a dryer according to the present invention;

[0020] Fig. 5 is an exploded perspective view illustrating a pulley assembly for transferring a driving force according to the present invention;

[0021] Fig. 6 is a cross-sectional view of a pulley assembly for transferring a driving force according to the present invention taken along in the longitudinal direction of a rotation shaft;

[0022] Fig. 7 is a cross-sectional view of Fig. 6 taken along line A-A´; and

[0023] Fig. 8 is a cross-sectional view illustrating a pulley assembly for transferring a driving force according to another embodiment of the present invention taken along in the longitudinal direction of a rotation shaft.

[0024] Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

[0025] Fig. 1 is a perspective view illustrating a dryer in which a pulley assembly for transferring a driving force according to the present invention is installed. Fig. 2 is an enlarged perspective view illustrating a state where the pulley assembly in Fig. 1 is installed.

[0026] Referring to Figs. 1 and 2 together, a safety cover 11 is provided in an upper part of a main body 10 of a dryer forming the appearance of the dryer. A door for putting the laundry in is installed at one side surface of the main body 10 of the dryer. A drum 20 is rotatably installed in the main body 10 of the dryer to store and dry wet laundry.

[0027] The drum 20 is rotatably installed in the main body 10 of the dryer. The drum 20 has a cylindrical shape, and is connected to a driving motor 40 provided in a lower part of the dryer by a driving force transmission belt 30 to rotate by receiving a rotational force upon rotation of the driving motor 40. A screw-coupled pulley 50 is provided in a rotation shaft 41 of the driving motor 40. While the driving force transmission belt 30 is engaged with the pulley 50, the drum 20 is surrounded through an optionally installed idle pulley 50A to be rotated by the operation of the driving force transmission belt 30.

[0028] Fig. 3 is an exploded perspective view illustrating a driving motor and a pulley assembly for transferring a driving force of a dryer according to the present invention. Fig. 4 is a cross-sectional view illustrating a driving motor and a pulley assembly for transferring a driving force of a dryer according to the present invention. Fig. 5 is an exploded perspective view illustrating a pulley assembly for transferring a driving force according to the present invention. Fig. 6 is a cross-sectional view of a pulley assembly for transferring a driving force according to the present invention taken along in the longitudinal direction of a rotation shaft. Fig. 7 is a cross-sectional view of Fig. 6 taken along line A-A´.

[0029] As illustrated in Figs. 3 to 7, the pulley 50 with which the driving force transmission belt 30 for rotating the drum 20 is engaged comprises a pulley body 51, a hub 52, a first locking ring frame 53 and a second locking ring frame 54. The pulley body 51 has the hub 52 in the center which is coupled to the rotation shaft 41 of the driving motor 40 and to which the driving force transmission belt 30 is fastened. The first locking ring frame 53 and the second locking ring frame 54 having a diameter greater than that of the hub 52 are formed respectively at both ends of the hub 52. Inclined surfaces 53A, 54A are formed respectively in an inner surface of the first locking ring frame 53 and an inner surface of the second locking ring frame 54. The circumference of the first and second locking ring frames 53, 54 is formed in a nut shape to facilitate the coupling of the pulley 50 and the rotation shaft 41 using a tool such as an electric spanner.

[0030] A screw thread 55 is formed on a circumferential surface of a rotation shaft through hole penetrating the center of the pulley body 51, and a screw thread 41A is formed at a distal end of the rotation shaft 41. The pulley 50 and the rotation shaft 41 are coupled therethrough. A pulley guide 60 coupled to the rotation shaft 41 is installed adjacent to the pulley 50 at one side of the first locking ring frame 53 of the pulley 50. The pulley guide 60 is illustrated as a separate member from the pulley 50, but the pulley guide 60 and the pulley 50 may be one member integrally formed.

[0031] The pulley guide 60 comprises a rotation shaft fitting hole 61A formed through an inner sleeve 61 in the center, an outer cover 62 having an inclined surface 62A integrally formed in the outer circumference of the inner sleeve 61 at regular intervals, a contact protrusion 63 inwardly protruding in the inner circumference of the inner sleeve 61 at regular intervals, and a flat surface 64. A reinforcing piece 65 is radially formed in the outer circumference of the inner sleeve 61 at regular intervals.

[0032] The pulley guide 60 and the rotation shaft 41 are coupled to each other so that the flat surface 64 of the pulley guide 60 is in surface contact with a cutting surface 41B of the rotation shaft 41. The outer cover 62 has the inclined surface 62A whose inclination decreases as it goes towards the pulley 50, and at the same time, the inclined surface 53A and the inclined surface 62A have a higher height as they go towards the driving motor 40 from the first locking ring frame 53 of the pulley body 51.

[0033] The inclined surface 53A of the first locking ring frame 53 and the inclined surface 62A of the outer cover 62 have a continuous circumferential surface, so that even when the driving force transmission belt 30 is separated from the hub 52 of the pulley 50 upon rotation of the rotation shaft 41 and moved along the inclined surface 62A of the pulley guide 60, the driving force transmission belt 30 can slide along the inclined surface 62A and return to the hub 52 of the pulley 50, thereby preventing the driving force transmission belt 30 from being separated from the hub 52 towards the driving motor 40 to hold the driving force transmission belt 30 continuously in position. Therefore, the separation of the driving force transmission belt 30 is prevented, and the driving force transmission belt 30 stably transfers a driving force to the drum 20. Accordingly, safety accidents or breakdown that may occur due to the stopping of the drum 20 caused by the separation of the driving force transmission belt 30 can be avoided.

[0034] Fig. 8 is a cross-sectional view illustrating a pulley assembly for transferring a driving force taken along in the longitudinal direction of the rotation shaft according to another embodiment of the present invention.

[0035] According to Fig. 8, the outer side of the inclined surface 53A of the pulley 50 is in surface contact with the inclined surface 62A of the outer cover 62 to have a continuous inclined surface. Accordingly, even when the driving force transmission belt 30 is separated from the hub 52 of the pulley 50 upon rotation of the rotation shaft 41 and moved along the inclined surface 62A of the pulley guide 60, the driving force transmission belt 30 can smoothly slide along the inclined surface 62A and the inclined surface 53A and return to the hub 52 of the pulley 50.

[0036] In this way, the separation of the driving force transmission belt 30 may be prevented through the inclined surface 62A of the pulley guide 60, which is simply made by sliding the separated driving force transmission belt 30 along the inclined surface 62A. Thus, it may be insufficient to return the separated driving force transmission belt 30 rapidly to the hub 52 of the pulley 50.

[0037] In order to solve said issue, the present invention returns the separated driving force transmission belt 30 to the hub 52 of the pulley 50 by rapidly pushing the driving force transmission belt 30 towards the hub 52 using the rotational force of the pulley guide 60, thereby allowing more stable operation of the dryer.

[0038] In the circumference of the inclined surface 62A of the outer cover 62 constituting the pulley guide 60, a separation preventing annular protrusion 62B having a locking jaw function is protrudingly formed. As illustrated in Figs. 6 and 8, the plurality of separation preventing annular protrusion 62B formed at regular intervals have a cross-section shape of a semi-ellipse or of a trapezoid with both upper ends curved. When the driving force transmission belt 30 separated from the hub 52 of the pulley 50 upon rotation of the rotation shaft 41 moves along the inclined surface 62A of the pulley guide 60, the driving force transmission belt 30 is hung in the separation preventing annular protrusion 62B formed in the circumference of the inclined surface 62A of the rotating outer cover 62, and the driving force transmission belt 30 is pushed back towards the pulley 50 by the rotational force of the separation preventing annular protrusion 62B. Accordingly, the driving force transmission belt 30 is returned to the hub 52 of the pulley 50, which is the original position.

[0039] In particular, the separation preventing annular protrusion 62B has a semielliptical cross section as illustrated in Fig. 6 or has a trapezoidal cross section with both upper ends curved as illustrated in Fig. 8. Accordingly, even when the pulley guide 60 rotates while the driving force transmission belt 30 deviating from its original position is hung in the separation preventing annular protrusion 62B, the inner surface of the driving force transmission belt 30 is smoothly in surface contact with the separation preventing annular protrusion 62B having a semielliptical cross section or a trapezoidal cross section with both upper edges curved, thereby preventing damage to the inner surface of the driving force transmission belt 30 and prolonging the life of the driving force transmission belt 30.

[0040] The separation preventing annular protrusion 62B may have a semielliptical cross section or a trapezoidal cross section with both upper edges curved. The separation preventing annular protrusion 62B having a semielliptical cross section increases the rotational force when the pulley guide 60 rotates, thereby rapidly pushing the driving force transmission belt 30 towards the hub 52 of the pulley 50. The separation preventing annular protrusion 62B having a trapezoidal cross section with both upper edges curved has the broad upper edge in an inclined state, allowing the separated driving force transmission belt 30 to smoothly slide, so that the driving force transmission belt 30 can be rapidly returned to the hub 52 of the pulley 50.

[0041] As illustrated in Figs. 6 to 8, the separation preventing annular protrusion 62B of the present invention may be formed as a screw thread in the circumference of the inclined surface 62A, and the separation preventing annular protrusion 62B may have a semielliptical cross section or a trapezoidal cross section with both upper edges curved.

[0042] The separation preventing annular protrusion 62B on which the screw thread is protrudingly formed moves the driving force transmission belt 30 towards the hub 52 of the pulley 50 while rotating in a screw manner upon rotation of the pulley guide 60 when the driving force transmission belt 30 separated from the hub 52 of the pulley 50 is positioned in the upper part of the separation preventing annular protrusion 62B, thereby more rapidly and smoothly returning and mounting the driving force transmission belt 30 to the hub 52 of the pulley 50 stably.

[0043] It should be noted that the description of the present invention described above is merely an example for understanding the present invention, and is not intended to limit the scope of the present invention. It should be construed that the scope of the present invention is defined by the appended claims, and all modifications and alternations of the present invention fall within the protection scope of the present invention.

Claims

1.A pulley assembly for transferring a driving force of a laundry dryer, comprising:a pulley 50 which is coupled to a distal end of a rotation shaft 41 of a driving motor 40 for driving a drum 20 of a laundry dryer, and in which a driving force transmission belt 30 for transferring a rotational force of the driving motor 40 to the drum 20 is hung; anda pulley guide 60 which is coupled to the rotation shaft 41 and installed at one side of the pulley 50;wherein the pulley guide 60 comprises a rotation shaft fitting hole 61A formed through an inner sleeve 61 in the center; and an outer cover 62 having an inclined surface 62A integrally formed in the outer circumference of the inner sleeve 61 at regular intervals,and wherein a separation preventing annular protrusion 62B is protrudingly formed in the circumference of the inclined surface 62A of the outer cover 62.2.The pulley assembly of claim 1, wherein the separation preventing annular protrusion 62B has a semielliptical cross section or a trapezoidal cross section with both upper ends curved.3.The pulley assembly of claim 1, wherein the separation preventing annular protrusion 62B is a screw thread formed in the circumference of the inclined surface 62A.4.The pulley assembly of claim 3, wherein the separation preventing annular protrusion 62B is formed as a screw thread having a semielliptical cross section or a trapezoidal cross section with both upper ends curved.5.The pulley assembly of claim 1, wherein the outer cover 62 forms the inclined surface 62A which becomes higher as it goes from a first locking ring frame 53 of a pulley body 51, and the outer circumference of the first locking ring frame 53 and the inclined surface 62A form a continuous inclined surface.

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