Direct drive motor in a washing machine

Abstract

Direct drive motor in a washing machine with: a stator (14) with a winding section with coils wound on it; a runner with a side wall (13b) and a back wall (13a) with a through hole (131) at a center, a ring disk (30) which is in close contact with an outer surface of the rear wall (13a) of the runner (13) and is firmly attached to it; a resin connector with a different vibration mode than the runner, which is arranged and firmly attached to an inside of the runner's back wall to support a washing shaft; a coupling device for mutually coupling the connector (16), the runner (13) and the disc (30), wherein the ring disc (30) is spaced apart from the washing shaft, wherein the runner (13) further comprises a hub (132) which projects from a rear wall (13a) to the washing shaft for strength reinforcement and forms a seating surface, and wherein the ring disk (30) has a bent section (310) on a circumference having a shape corresponding to a shape of a bent section of the hub (132).

Description

Technical area

[0001] The invention relates to washing machines and, more particularly, to a direct drive motor applicable to a drum washing machine and the like. Background of the technology

[0002] Generally, a pulsator washing machine under the control of a microcomputer washes clothes and bedding to remove dirt by means of a softening effect of detergent, friction of water circulation after rotation of a pulsator and impact of the pulsator on laundry, after laundry type and quantity are detected by a sensor to automatically set a washing process accordingly, and washing water with proper level is supplied according to the laundry type and quantity.

[0003] On the other hand, the drum washing machine, which washes clothes by means of friction between the clothes and the drum rotated by the driving force of a motor in a state where the detergent, washing water and clothes are put into the drum, causes almost no damage to the clothes, does not cause the clothes to tangle, and provides a beating and rubbing washing effect to the clothes.

[0004] In the following, a drum washing machine of related technology is described using Fig. 1 briefly described.

[0005] In Fig. 1 is a longitudinal section through a drum washing machine of the related art, which is provided with a tub (liquor container) 2 in a housing 1 and a drum 3 which is rotatably arranged at a central portion of the tub 2.

[0006] Under the tub 2 there is a motor 5a with a motor pulley 18 coupled thereto via a shaft, and at the rear of the drum 3 there is a drum shaft arranged thereon with a drum pulley 19 coupled thereto.

[0007] Accordingly, the drum pulley 19 on the drum shaft and the motor pulley 18 coupled to the motor 5a are connected by a belt 20, a power transmission member, for transmitting driving power from the motor to the drum 3 via the belt 20.

[0008] A door 21 is arranged on a front side of the housing 1, with a seal 2 being arranged between the door 21 and a tub 2.

[0009] Between a bottom of an upper portion of the housing 1 and an upper side of an outer periphery of the tub 2, there are further provided hanging springs 23 for suspending the tub, and between a bottom of the housing 1 and a bottom of the outer periphery of the tub 2, there are dampers 24 for damping vibrations of the tub 2 which occur during spinning.

[0010] However, the related art washing machine has the disadvantage shown below because the related art washing machine has a structure in which the driving force is transmitted from the motor 5a to the drum 3 via the motor pulley 18, the drum pulley 19, and the belt 20 connecting the motor pulley 18 and the drum pulley 19.

[0011] Since the drive force is initially not transmitted directly to the drum 3 but via the belt 20, which is wound around the motor pulley 18 and the drum pulley 19, energy is lost during the drive force transmission.

[0012] In addition, since the driving force to the drum 3 is not transmitted directly but via many components such as the motor pulley 18, the drum pulley 19, the belt 20, etc., a lot of noise is generated during the power transmission.

[0013] The numerous components, such as the motor pulley 18, the drum pulley 19, the belt 20, etc., required to transmit the driving force of the motor 5a to the drum 3, increase the assembly effort of the product.

[0014] In addition, the many components required to transmit the driving force of the motor 5a to the drum 3 increase the number and frequency of errors.

[0015] In short, the indirect transmission of the driving force from the motor 5a to the drum 3 by means of the motor pulley, the drum pulley and the belt easily causes disturbances and noise, involves many factors for energy waste and impairs the washing performance

[0016] In addition, the stainless steel tub 2 of the drum washing machine of the related technology is expensive, difficult to process and heavy.

[0017] Furthermore, instead of indirectly transmitting the driving force from the motor to the drum by means of the belt and pulleys, a direct drive drum washing machine system has been proposed, but this system has a disadvantage that a stand directly attached to a rear wall of the tub does not maintain the concentric position of the stand, as damage or deformation of a mounting portion occurs due to vibration of the motor.

[0018] If a bearing housing is manufactured separately from the tub to solve this problem, not only is assembly difficult, but the assembly also takes up a lot of space because the entire bearing housing protrudes from the tub. When the bearing housing is secured with screws or bolts, the bearing housing is not fully supported but only partially supported on one side, making the attachment prone to vibration. Furthermore, since a complex water protection structure is required not only for the bearing itself but also between the tub and the bearing, this design has manufacturing disadvantages.

[0019] In addition, the bearing housing must have an inner collar and an outer collar, which are separate components to support the bearing inside, and the manufacturing of the rotor is very difficult due to individual permanent magnets, a steel sheet, and a rear yoke on the back of the steel sheet.

[0020] To solve this problem, a drive unit design was also proposed in which the motor has a sheet steel rotor with a separately provided rear yoke and the bearing housing does not protrude outwards from the tub.

[0021] However, since the structure includes a rotor having an axial projection from a rear wall of the rotor and a thread on an inner peripheral surface of the projection for fastening a connector to the thread in the projection with a screw, the structure has a complicated rotor manufacturing process and poor workability, requiring the projection and the thread on the inner peripheral surface of the projection to be formed and burrs to be removed therefrom when processing the rotor.

[0022] Further prior art is shown in the documents DE 101 10 903 A1, DE 196 31 384 C1, DE 23 28 886 A1, DE 533 988 A, DE 600 15 045 T2, FR 528 969 A, GB 189 903 A and US 7 251 962 B2. Disclosure of the inventionTechnical problem

[0023] The invention has for its object to provide a direct drive motor in a washing machine, in which a structure of a drive unit in a drum washing machine is improved to improve the processability and rigidity of the tub in order to reduce vibrations during rotation of the rotor. Technical solution

[0024] The object of the invention can be achieved by providing a direct drive motor in a washing machine, comprising: a stator 14 having a winding portion with coils wound thereon, a rotor having a side wall 13b and a rear wall 13a with a through hole 131 at a center, an annular disc that is in close contact with the rear wall 13a of the rotor 13 and is fixedly attached thereto, a resin connector having a different vibration mode than the washing shaft, which is fixedly attached to the rear wall of the rotor for supporting the washing shaft, a coupling device for mutually coupling the connector 16, the rotor 13, and the disc 30.

[0025] Preferably, the rotor 13 is constructed from sheet steel by pressing to form the side wall 13b and the rear wall 13a in one piece.

[0026] The rotor 13 has fastening through-holes 138 around the through-hole 131, the disc 30 has fastening through-holes 300a on one surface thereof corresponding to the fastening through-holes 138 in the rear wall of the rotor, the connector has fastening through-holes 162 corresponding to the fastening through-holes 138 in the rotor 13, and the coupling device has bolts 'B' inserted through the fastening through-holes 162, 138 and 300a, and nuts 'N' fastened to threads on the bolts 'B' for holding the connector 16, the rotor and the disc.

[0027] Preferably, the annular disk 30 further has positioning holes in which the positioning projections 160 on the connector 16 are respectively placed, separate from the fastening through-holes 300a, and the positioning holes are formed in the circumferential direction of an imaginary circle having a different diameter than an imaginary circle connecting centers of the fastening through-holes 300a in the annular disk 30.

[0028] Preferably, the rotor 13 further includes a hub 132 projecting from the rear wall toward the washing shaft for strength reinforcement and forming a seating surface, and the annular disc 30 includes a bent portion 310 on a circumference having a shape in accordance with a shape of a bent portion of the hub 132.

[0029] Furthermore, preferably, the annular disc 30 is in close contact with and fixedly attached to an outer side of the rear wall 13a of the rotor 13, and the connector 16 is arranged on an inner side of the rear wall 13a of the rotor 13.

[0030] In another aspect of the invention, a direct drive motor in a washing machine comprises: a stator 14 having a winding section with coils wound thereon, a rotor having a side wall 13b and a rear wall 13a with a through hole 131 at a center and fastening through holes 138 around the through hole 131, a washer 30 that is in close contact with the rear wall 13a of the rotor 13 and is fixedly attached thereto, the washer 30 having fastening projections 300 projecting from a surface thereof toward a washing shaft in correspondence with fastening through holes 138 in the rear wall of the rotor, each of the fastening projections 300 having a threaded fastening hole 300b on an inner circumference, a resin connector having a different vibration mode than the washing shaft, which is fixedly attached to the rear wall of the rotor with bolts 'B',which are guided through the fastening holes 138 in the rotor and fastened to the fastening lugs 300 on the annular disc 30.

[0031] In another aspect of the invention, a direct drive motor in a washing machine comprises: a stator 14 having a winding portion with coils wound thereon, a rotor having a side wall 13b and a rear wall 13a with a through hole 131 at a center and fastening through holes 138 around the through hole 131, a washer 30 that is in close contact with the rear wall 13a of the rotor 13 and is fixedly attached thereto, the washer 30 having fastening through holes 300a in one surface thereof corresponding to fastening through holes 138 in the rear wall of the rotor, a resin connector 16 having a different vibration mode than the washing shaft and fixedly attached to an inner side of the rear wall of the rotor for supporting the washing shaft, the connector having fastening through holes 162 corresponding to the fastening through holes 138 around the through hole 131, Bolt 'B',which are guided through the fastening through-holes in the connector 16, the rotor 13 and the disc 30, and nuts 'N' which are fastened to threads on the bolts 'B' for holding the connector 16, the rotor and the disc together. Beneficial effects

[0032] The direct drive motor in a washing machine of the invention has the following advantages.

[0033] Due to the direct drive motor, the drum washing machine has less noise, errors and power loss.

[0034] In addition, the invention improves the machinability during manufacture of the rotor and reduces vibrations from the rotor by means of the disc provided on the inside or outside of the rear wall of the rotor.

[0035] Furthermore, the metal bearing housing allows application to a product with a dry function because the metal bearing housing does not show any thermal deformation.

[0036] In addition, the runner made of sheet steel allows for pressing with good processability, which requires a shorter production time with increased productivity.

[0037] The magnet seating surface of the rotor improves the machinability of arranging the magnets, and the drain holes, cooling fins and ventilation holes therein prevent the motor from overheating, which improves the reliability and service life of the motor.

[0038] The connector with a different vibration mode than the rotor allows to reduce vibrations from the rotor to the shaft, and the support effectively supports the stator and maintains its concentric position. Short description of the drawings

[0039] The accompanying drawings, which are intended to provide a better understanding of the invention, illustrate one or more embodiments of the invention and, together with the description, serve to explain the principle of the invention. They show: Fig. 1 a longitudinal section through a drum washing machine of related art; Fig. 2 shows a longitudinal section through a drum washing machine according to a preferred embodiment of the invention; Fig. 3 a longitudinal section through part “A” in Fig. 2, which shows a drive unit of the drum washing machine according to a preferred embodiment of the invention; Fig. 4 an enlarged view of part “B” in Fig. 3; Fig. 5 a perspective view of a ring disc; Fig. 6 a perspective view of the runner in Fig. 2 with a partially cutaway view; Fig. 7 an enlarged view of part “C” in Fig. 6; Fig. 8 a perspective view from below of Fig. 6; Fig. 9 a perspective view of the stand in Fig. 2; Fig. 10 a perspective view of the connector in Fig. 2; Fig. 11 a perspective view from below of Fig. 10; Fig. 12 shows a longitudinal section through a drive unit in a drum washing machine according to another preferred embodiment of the invention; Fig. 13 and Fig. 14 Perspective views of a connector and a runner according to the further preferred embodiment of the invention. Preferred embodiment of the invention

[0040] In the following, the preferred embodiments of the invention will be discussed in more detail, examples of which are shown in the accompanying drawings of Fig. 2 to 11 are shown.

[0041] Fig. 2 shows a longitudinal section through a drum washing machine according to a preferred embodiment of the invention and Fig. 3 a longitudinal section through part “A” in Fig. 2, which shows an enlarged view of a drive unit of the drum washing machine according to a preferred embodiment of the invention.

[0042] Fig. 4 shows an enlarged view of part “B” in Fig. 3 Fig. 5 shows a perspective view of a ring disc. Fig. 6 shows a perspective view of the runner in Fig. 2, Fig. 7 a perspective view of part “C” in Fig. 6 and Fig. 8 a perspective view from below of Fig. 6.

[0043] Fig. 9 shows a perspective view of the stand in Fig. 2, Fig. 10 a perspective view of the connector in Fig. 2 and Fig. 11 a perspective view from below of Fig. 10.

[0044] According to the invention, in a drum washing machine having a tub 2 in a cabinet 1, a drum 3 in the tub 2, a shaft 4 connected to the drum 3 for transmitting driving force from a motor 5 to the drum 3, and bearings on an outer peripheral surface of opposite ends of the shaft 4, the tub 2 is formed of plastic, and a bearing housing 7 made of metal is provided at a center of a rear wall 200 of the tub 2 for supporting the bearings on the outer peripheral surface of opposite ends of the shaft 4.

[0045] The metal bearing housing 7 is inserted during injection molding of the plastic tub 2 in such a way that the bearing housing 7 becomes one piece with the tub 2 at its rear wall.

[0046] Preferably, the bearing housing 7 is made of aluminum.

[0047] Furthermore, the bearing housing 7 has steps 8a and 8b on an inner peripheral surface of the bearing housing 7 for supporting a front bearing 6a and a rear bearing 6b, respectively, and for preventing the bearings from falling off the bearing housing 7.

[0048] Of the steps 8a and 8b on an inner peripheral surface of the bearing housing 7, the step 8a at a front side has a shape "¬" to form a structure for supporting a rear end of the front bearing 6a, and the step 8b at the rear side has an "L" shape to form a structure for supporting a front end of the rear bearing 6b.

[0049] On an outer peripheral surface of the shaft 4 in the bearing housing 7 for transmitting driving force from the motor 5 to the drum 3, positioning steps 9a and 9b are provided at a front and a rear side thereof for positioning the front bearing 6a and the rear bearing 6a on the shaft 4.

[0050] The shaft 4 has a front end fixedly attached to a star 10 on the rear wall of the drum 3, a brass bushing 4 which is press-fitted onto a region of the shaft 4 starting from an exposed portion of the shaft 4 behind the star 10 to the front bearing 6a to prevent rusting of the shaft 4, and a sealing part 12 on an outer side of the bushing 11 to prevent water ingress.

[0051] There are also a rotor 13 of the direct drive motor 5, which is coupled to a center of a rear end portion of the shaft 4, and a stator 14 of the direct drive motor 5 on an inner side of the rotor 13, which is fixed to the rear wall 200 of the tub 2.

[0052] According to Fig. 6 to 8, the rotor 13 constructed of sheet steel has a side wall 13b extending forward from a periphery of a rear wall 13a and has a bent portion formed circumferentially with a seating surface 130 for magnets 13c arranged on an inner peripheral surface of the side wall 13a, and a hub 132 at a center of the rear wall 13a with through holes 131 formed therein for passing threaded portions of fastening members 15b, such as bolts, to couple the rotor 13 to the shaft 4.

[0053] The hub 132 is bent in the washing shaft direction to increase the rigidity of the rotor and to form a seating surface of a connector.

[0054] Furthermore, several fastening through holes 138 are provided around the through hole 131 in the rotor 13.

[0055] On an outer side of the rear wall 13a of the rotor 13 there is an annular disc 30.

[0056] The annular disc 30 has a plurality of fastening through holes 300a corresponding to the fastening through holes 138 in the rear wall of the rotor.

[0057] The disc has a bent portion 310 at a periphery with a shape in accordance with the hub 132.

[0058] In addition, the plurality of through holes 300a in the annular disk 30 may be located on at least two lines in the circumferential direction as imaginary circles from centers of the fastening through holes 300a, which form diameters different from each other.

[0059] Fig. Figure 4 shows a section through a connector 16, the hub 132 of the rotor, and the washer 30, which are secured together by a plurality of bolts 'B' that pass through and engage nuts 'N'. The mounting holes through which the bolts 'B' pass do not require threads.

[0060] It is preferred to form the rotor 13 by pressing.

[0061] Around the hub 132 of the rotor 13, there are a plurality of cooling fins 133 formed in the radial direction for blowing air to the stator 14 when the rotor 13 is rotated to cool heat from the stator 14, each with a predetermined length in the radial direction.

[0062] The cooling fins 133 are formed by piercing such that the cooling fins 133 are bent 90° from the rear wall to the open portion, and through holes 134 formed by piercing serve as ventilation holes.

[0063] There are also embossed sections 135 between adjacent cooling fins 133 on the rear wall 13a of the rotor 13 for reinforcing the rotor 13, each with a drain hole 136 for water drainage.

[0064] Around the through hole 131 in the hub 132 of the rotor 13, a plurality of circumferentially formed fastening through holes 138 are provided for fastening the connector 16 in engagement with an outer peripheral surface of the rear end of the shaft 4, which is exposed on a rear side of the rear bearing 6b, with a spline. The fastening through holes 138 may be formed on at least two circumferential lines as imaginary circles from the centers of the fastening through holes 162, which have different diameters from each other.

[0065] The connector 16 is made of resin with a different vibration mode than the steel plate rotor 13 and also serves as a bushing for the rotor.

[0066] According to Fig. 3, Fig. 10 and Fig. 11, the connector 16 further has fastening through-holes 162 in the circumferential direction of a periphery corresponding to the fastening through-holes 138 in the hub 132 of the rotor. The fastening through-holes 162 may be formed on at least two lines in the circumferential direction as imaginary circles from the centers of the fastening through-holes 162, which have different diameters from each other.

[0067] Further, the connector 16 has a spline 164 on an inner peripheral surface of the hub 163 in correspondence with the spline on the rear end of the shaft 4 and may have reinforcing ribs 161 on an outer side of the hub 163 of the connector 16 for reinforcing the hub 163.

[0068] Furthermore, on the rear wall 200 of the tub 2, there is a hub 201 for inserting the bearing housing 7 therein during injection molding of the tub, and on an outer side of the hub 201, fastening projections 202 are formed at regular intervals in the circumferential direction for firmly attaching the stand 14 to the rear wall 200 of the tub 2 with fastening parts 15a.

[0069] Between the rear wall 200 of the tub 2 and the stand 14 there is a support 17 having a shape almost identical to a contour of the rear wall 200 of the tub, for fastening to the rear wall 200 of the tub when arranging the stand 14, for supporting the stand 14 and for maintaining the concentric position of the stand 14.

[0070] The support 17 has an outer side in close contact with an inner side of a rib 203 on the rear wall 200 of the tub and an inner side in close contact with an outer periphery of a rear end of the bearing housing 7, which is not surrounded by the hub 201 at the center of the rear wall 200 of the tub but is exposed therefrom.

[0071] The support 17 and the rear wall 200 of the tub are coupled together by a plurality of fastening parts 15d, which pass through an outer peripheral surface of the support 17 and are fixed to the hub 204 on the rear wall of the tub. To fix the stand 14 to the support 17, other fastening parts 15a are used on an inner side of the fastening parts 15a.

[0072] In addition, according to Fig. 3 and Fig. 9, the stator 14 of the motor 5 comprises an annular frame 140 and a coil 142 wound on a winding portion on an outer side of the frame 140, wherein fixing ribs 143 are integrally formed on an inner side of the frame 140 for fixing the stator 14 to the rear wall 200 of the tub.

[0073] The operation of the drum washing machine of the invention is described below.

[0074] When the rotor 13 begins to rotate when current flows to the coils 142 on the stator 14 in a sequence under the control of a motor drive controller (not shown), the shaft 4 coupled to the connector 16 coupled to the rotor with the spline rotates to transmit power to the rotor 13 via the shaft 4 accordingly.

[0075] In addition, the drum washing machine with the drive unit of the invention applied thereto has the characteristics shown below.

[0076] The formation of the tub 2 from a plastic with good heat resistance is lightweight and has good processability when the tub 2 is injection molded.

[0077] The formation of the bearing housing 7 from a metal, e.g., an aluminum alloy, enables application even to a drum washing machine with a drying cycle, since the bearing housing 7 does not show deformation at high temperature.

[0078] The metal bearing housing, which is inserted into the hub 200 of the rear wall 200 of the tub during injection molding of the plastic tub 200 to be integral with the tub 2, eliminates a separate step for arranging the bearing housing 7 on the rear wall of the tub 200.

[0079] This allows the assembly process to be further simplified in order to reduce the required assembly effort.

[0080] The step 8a with the shape “¬” on the front side of the inner peripheral surface of the bearing housing 7 and the step with the shape “L” on its rear side enable the rear end of the front bearing 6a and the front end of the rear bearing 6b to be supported.

[0081] That is, the steps 8a and 8b on opposite sides of the inner peripheral surface of the metal bearing housing can support the bearings 6a and 6b without falling off the bearing housing 7.

[0082] In addition, the positioning steps 9a and 9b on a front and rear outer peripheral surface of the shaft 4, which is arranged in the bearing housing 7 for power transmission from the motor 5 to the drum 3, enable easy positioning of the front bearing 6a and the rear bearing 6b on the shaft 4.

[0083] Furthermore, the fastening of the front end of the shaft 4 to a star 10 on the rear wall of the drum 3 and the brass bushing 11 which is pressed onto a region of the shaft 4 starting from an exposed portion of the shaft 4 behind the star 10 to the front bearing 6a for preventing rust of the shaft 4 make it possible to prevent the shaft 4 from rusting.

[0084] The sealing part 12 on an outer side of the bushing 11 prevents water from entering the bearing.

[0085] The rotor 13 of the direct drive motor 5 is coupled to a center of a rear end portion of the shaft 4, and the stator 14 is located on an inner side of the rotor 13, the rotor 13 having a side wall 13b extending forward from a periphery of a rear wall 13a with a bent portion circumferentially formed with a seat surface 130 for supporting magnets 13c arranged on an inner peripheral surface of the side wall 13a, which enables easy manufacturing of the rotor.

[0086] The hub 132 at a center of the rear wall 13a of the rotor 13 having through holes 131 formed therein allows threaded portions of fastening parts 15b, such as bolts, to pass through to couple the rotor 13 to the shaft 4, and the plurality of cooling fins 133, each formed with a predetermined length in the radial direction, blow air to the stator 14 when the rotor 13 is rotated to cool heat from the stator 14.

[0087] The cooling fins 133 are formed by piercing toward an open portion of the rotor 13, and the through holes 134 formed by the piercing serve as ventilation holes.

[0088] The rotor 13 formed from steel sheet by pressing significantly shortens a time required for manufacturing the rotor 13, which improves productivity.

[0089] In addition, the embossed portions 135 between adjacent cooling fins 133 on the rear wall 13a of the rotor 13 improve an overall rigidity of the rotor 13, and the drain hole 136 in the embossed portion 135 enables water drainage.

[0090] The fixing through holes 138 and the positioning holes 139 for positioning the connector 16 around the through hole 131 in the hub 132 of the rotor 13 enable the connector 16 to be easily arranged in coupling with the outer peripheral surface of the rear end of the shaft 4, which is exposed behind the rear bearing 6b, in spline engagement with the rotor.

[0091] That is, once the positioning projections 160 of the connector 16 are placed in the positioning holes 139, the mounting through holes 138 and 162 are automatically aligned, allowing easy assembly of the connector 16 and rotor 13 by inserting mounting bolts through the mounting through holes 138 and 162 of the rotor 13 and connector 16, respectively, and securing the mounting bolts in the mounting bosses 300 of the disk 30.

[0092] The disc 30 in close contact with the back wall of the rotor increases a rigidity of the rotor to reduce noise from the rotor.

[0093] The connector 16, a resin injection-molded part with a different vibration mode than the steel plate rotor 13, dampens the vibrations from the rotor 13 before they are transmitted to the shaft 4.

[0094] Furthermore, the engagement of the spline 164 on the inner peripheral surface of the hub 163 of the connector 16 with the spline 400 on the rear end portion of the shaft 4 enables the transmission of a rotational force from the rotor 13 to the shaft 4 via the connector 16 in an unchanged form.

[0095] The reinforcing ribs 161 on the outside of the hub 163 of the connector 16 increase the strength of the connector.

[0096] The fastening projections 202 on an outer side of the hub 201 in the circumferential direction at regular intervals enable the fastening of the stand 14 to the rear wall 200 of the tub 2. The support 17 between the rear wall 200 of the tub 2 and the stand 14, which has a shape almost identical to a contour of the rear wall 200 of the tub for fastening to the rear wall 200 of the tub when arranging the stand 14, supports the stand 14 and maintains its concentric position.

[0097] That is, once the support 17 is attached to the support attachment bosses 204 on the tub rear wall 200 with the attachment parts 15a, a front side of the support 17 is in close contact with the inside of the rib 203 on the tub rear wall 200, and the inside of the support 17 is in close contact with the outer periphery of the rear end of the bearing housing 7, which is not surrounded by the hub 201 in the tub rear wall 200 but is exposed therefrom, to support and maintain the concentric position of the stator 14. Embodiment of the invention

[0098] Based on the attached drawings of Fig. 12 to 14, a further embodiment of the invention is described below.

[0099] Fig. 12 shows a longitudinal section through a drive unit in a drum washing machine according to the further preferred embodiment of the invention with an annular disc whose shape differs from that in the first embodiment.

[0100] That is, the washer 30 according to the further preferred embodiment of the invention has mounting bosses 300 protruding from a surface of the washer in correspondence with the mounting through-holes 138 in the rear wall of the rotor. The mounting boss 300 has a threaded mounting hole 300b. That is, unlike the previous embodiment, no nut 'N' is required.

[0101] On a circumference of the disc 30 there is a bent portion 310 having a shape in accordance with the hub 132.

[0102] Furthermore, the plurality of fastening projections 300 on the annular disk 30 may be formed on at least two lines in the circumferential direction such that imaginary circles of centers of the fastening through holes 300 form diameters different from each other.

[0103] Preferably, the rotor 13 is pressed.

[0104] The connector 16 is made of resin with a different vibration mode than the steel plate rotor 13 and also serves as a bushing for the rotor.

[0105] According to Fig. 12, the connector 16 has fastening through holes 162 in a periphery in the circumferential direction corresponding to the fastening through holes 138 in the hub 132 of the rotor 13.

[0106] In addition, the connector 16 has a spline 164 on an inner peripheral surface of the hub 163 in correspondence with the spline on the rear end portion of the shaft 4 and reinforcing ribs 161 on an outer side of the hub 163 of the connector 16 for strengthening the hub 163.

[0107] When assembling the rotor 13 and the connector, the connector is inserted from an inside to an outside of the rotor, aligning the mounting through holes 138 and 162 of the rotor 13 and connector 16.

[0108] In this state, the annular disc 30 is brought into close contact with an outer side of the hub 132 on the rear wall of the rotor, while the mounting holes 300b in the mounting bosses 300 are aligned with the mounting through holes 138 and 162 of the rotor 13 and connector 16.

[0109] Bolts 'B' are then passed through the mounting holes 138 and 162 of the rotor 13 and connector 16 and secured to the mounting bosses 300 on the disc 30.

[0110] This assembles the connector 16 and runner 13.

[0111] The disc 30 in close contact with the back wall of the rotor increases a rigidity of the rotor to reduce noise from the rotor.

[0112] The connector 16, a resin injection-molded part with a different vibration mode than the steel plate rotor 13, dampens the vibrations from the rotor 13 before they are transmitted to the shaft 4.

[0113] Furthermore, the engagement of the spline 164 on the inner peripheral surface of the hub 163 of the connector 16 with the spline 400 on the rear end portion of the shaft 4 enables the transmission of a rotational force from the rotor 13 to the shaft 4 via the connector 16 in an unchanged form.

[0114] The reinforcing ribs 161 on the outside of the hub 163 of the connector 16 increase the strength of the hub 163.

[0115] Furthermore, Fig. 13 and Fig. 14 are perspective views of a connector and a slider applicable to the embodiment, respectively, wherein the connector has not only the fastening through holes 162 but also the positioning protrusions 160, and the slider has positioning holes 139 in correspondence with the positioning protrusions on the connector.

[0116] That is, between the fastening through-holes 162 in the connector there are positioning projections 160 which are formed integrally with the connector, so that the fastening through-holes 138 in the rotor 13, the fastening through-holes 162 in the connector 16 and the fastening lugs 300 on the disk 30 are automatically aligned when the positioning projections 160 are respectively inserted into the positioning holes 139 in the rotor 13.

[0117] In this case, the positioning protrusions on the connector in accordance with the positioning holes in the slider improve the machinability when assembling the slider and connector.

[0118] Of course, it is necessary that the washer 30 has positioning holes (not shown) for inserting the positioning projections 160 on the connector 16 in addition to the fixing through holes 300a (see Fig. 4 and Fig. 2D) and the mounting holes 300b (see Fig. 12) in the fastening lugs 300.

[0119] In this case, imaginary center lines connecting the positioning holes or the positioning projections may have a different diameter from a diameter of an imaginary center line connecting centers of the fastening through holes to form a total of two lines in the circumferential direction.

[0120] Furthermore, it will be apparent to those skilled in the art that various modifications and variations may be made to the invention without departing from the spirit or scope of the inventions.

[0121] That is, although not shown, it is of course possible that, in contrast to Fig. 4 and Fig. 12, which show a case where the disc 30 is inserted from the rear to the front of the rotor, the disc 30 can be inserted from the front to the rear of the rotor. As will be apparent to those skilled in the art, this case can be accompanied by a slight modification of the annular disc.

[0122] Although not shown, it is equally possible that, in contrast to Fig. 4 and Fig.12, which show a case where the connector 16 is inserted from the rear to the front of the rotor, the connector 16 can be inserted from the front to the rear of the rotor. As will be apparent to those skilled in the art, this case may involve a slight modification of the connector. Industrial applicability

[0123] The direct drive motor in a washing machine of the invention makes it possible to provide a drum washing machine with less noise, error and power loss, to improve the workability in manufacturing the rotor and to reduce vibration from the rotor by means of the washer provided on the inside or outside of the rear wall of the rotor.

[0124] In addition, the rotor made of steel plate, which can be manufactured by pressing with good processability, requiring a shorter manufacturing time, enables the provision of a drum washing machine with improved productivity, where the connector has a different vibration mode from the rotor, which can reduce vibration from the rotor to the shaft, and the support effectively supports the stator and maintains its concentric position.

Claims

[1] Direct drive motor in a washing machine with: a stator (14) having a winding section with coils wound thereon; a runner having a side wall (13b) and a rear wall (13a) with a through hole (131) at a center, an annular disc (30) which is in close contact with an outer side of the rear wall (13a) of the rotor (13) and is fixedly attached thereto; a resin connector having a different vibration mode from that of the rotor, arranged and fixedly attached to an inner side of the rear wall of the rotor for supporting a washing shaft; a coupling device for mutually coupling the connector (16), the rotor (13) and the disc (30), wherein the annular disc (30) is spaced from the washing shaft, wherein the rotor (13) further comprises a hub (132) projecting from a rear wall (13a) to the washing shaft for strength reinforcement and forming a seating surface, and wherein the annular disc (30) has a bent portion (310) on a circumference having a shape in accordance with a shape of a bent portion of the hub (132). [2] A direct drive motor according to claim 1, wherein the rotor (13) is constructed from sheet steel by pressing to integrally form the side wall (13b) and the rear wall (13a). [3] Direct drive motor according to claim 1, wherein the rotor (13) has fixing through holes (138) around the through hole (131), the disc (30) has fastening through holes (300a) on one surface thereof corresponding to the fastening through holes (138) in the rear wall of the rotor, the connector has fastening through holes (162) corresponding to the fastening through holes (138) in the rotor (13), and the coupling device comprises bolts ('B') inserted through the fastening through-holes (162), (138) and (300a), and nuts ('N') fastened to threads on the bolts ('B') for holding the connector (16), the rotor and the disc. [4] A direct drive motor according to claim 1, wherein the annular disc (30) further comprises positioning holes in which the positioning projections (160) on the connector (16) are respectively placed, separate from the fixing through holes (300a). [5] A direct drive motor according to claim 4, wherein the positioning holes are formed in the circumferential direction of an imaginary circle having a different diameter than an imaginary circle connecting centers of the fixing through-holes (300a) in the annular disk (30). [6] Direct drive motor in a washing machine with: a stator (14) having a winding section with coils wound thereon; a runner having a side wall (13b) and a rear wall (13a) with a through hole (131) at a center and fixing through holes (138) around the through hole (131); an annular disc (30) in close contact with and fixedly attached to an outer surface of the rear wall (13a) of the rotor (13), the annular disc (30) having fastening projections (300) projecting from a surface thereof toward a washing shaft in correspondence with fastening through-holes (138) in the rear wall of the rotor, each of the fastening projections (300) having a fastening hole (300b) with a thread on an inner circumference; a resin connector having a different vibration mode than the rotor, which is arranged and fixedly attached to an inner side of the rear wall of the rotor by bolts (B) which are passed through the fastening through-holes (138) in the rotor and fastened to the fastening projections (300) on the annular disc (30); wherein the annular disc (30) is spaced from the washing shaft, wherein the rotor (13) further comprises a hub (132) projecting from the rear wall (13a) to the washing shaft for strength reinforcement and forming a seating surface, and wherein the annular disc (30) has a bent portion (310) on a circumference having a shape in accordance with a shape of a bent portion of the hub (132). [7] A direct drive motor according to claim 6, wherein the rotor (13) is constructed from sheet steel by pressing to integrally form the side wall (13b) and the rear wall (13a). [8] Direct drive motor according to claim 7, wherein the fastening lugs (300) on the annular disc (30) lie on at least two lines in the circumferential direction as imaginary circles which connect the centers of the fastening lugs 300 and have diameters which differ from one another. [9] A direct drive motor according to claim 7, wherein the annular disc (30) further comprises positioning holes in which the positioning projections (160) on the connector (16) are respectively placed, separate from the fixing bosses (300). [10] A direct drive motor according to claim 9, wherein the positioning holes are formed in the circumferential direction of an imaginary circle having a different diameter than an imaginary circle connecting centers of the fixing through bosses (300) on the annular disk (30). [11] Direct drive motor in a washing machine with: a stator (14) having a winding section with coils wound thereon; a runner having a side wall (13b) and a rear wall (13a) with a through hole (131) at a center and fixing through holes (138) around the through hole (131); a resin connector (16) having a different vibration mode than the rotor, which is fixedly attached to an inner side of the rear wall of the rotor for supporting a washing shaft, the connector having fixing through holes (162) corresponding to the fixing through holes (138) around the through hole (131); an annular disc (30) which is in close contact with an outer side of the rear wall (13a) of the rotor (13) and is fixedly attached thereto, the annular disc (30) having fastening through-holes (300a) in a surface thereof corresponding to the fastening through-holes (138) in the rear wall of the rotor and positioning holes in which the positioning projections 160 on the connector (16) are inserted; and a coupling device for coupling the connector (16), the rotor (13) and the annular disc (30), wherein the annular disc (30) is spaced from the washing shaft, wherein the rotor (13) further comprises a hub (132) which projects from the rear wall (13a) to the washing shaft for strength reinforcement and forms a seating surface, wherein the annular disc (30) has a bent portion (310) on a circumference having a shape in accordance with a shape of a bent portion of the hub (132). [12] A direct drive motor according to claim 11, wherein the positioning holes are formed in the circumferential direction of an imaginary circle having a different diameter than an imaginary circle connecting centers of the fixing through-holes (300a) in the annular disk (30).

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