JP4857197B2 - Drum washing machine - Google Patents

Description

  The present invention relates to a vibration isolation technique for a drum type washing machine.

  A general drum-type washing machine includes a water tub elastically supported in a washing machine housing, a washing tub provided to be rotatable by tilting the rotation axis about 0 to 30 ° with respect to the horizontal in the water tub, It is provided in the rear part of the water tub, and is configured by a motor that rotationally drives the washing tub, and an opening of clothing is provided on the front surface of the housing.

  Put clothes in this washing tub and wash. Before the clothes after washing are dried and dried, it is necessary to remove as much moisture as possible from the clothes. Therefore, there are many small holes on the side of the washing tub, and the washing tub is rotated at high speed to perform centrifugal dehydration.

  In performing centrifugal dehydration, it is difficult to evenly disperse clothing in the washing tub, resulting in a shift of clothing. When rotating at a high speed in this state, a large centrifugal force is generated and a large vibration is generated. In order to release this large centrifugal force and reduce vibration, the water tank is elastically supported by a spring. If it is supported only by a spring, vibration cannot be suppressed at the time of resonance, and a damper is provided to provide a damping action. The springs and dampers are adjusted so that vibration can be reduced and centrifugal dewatering can be performed in an appropriate state.

  By reducing the spring constant of the spring, it is possible to make it difficult to transmit the vibration of the water tank to the outside of the washing machine. However, if the spring constant is reduced, it will sink greatly when clothes or washing water is added, the spring will adhere, and vibration during washing cannot be reduced, and the load on the spring will increase and the spring will deteriorate. It will end up.

  Further, if the damping performance of the damper is increased, the damper can be started smoothly while suppressing the resonance that occurs when starting dehydration. However, if the damping performance is too high, vibration is greatly transmitted to the outside of the washing machine at the time of high rotation.

  In the prior art described in Japanese Patent Laid-Open No. 9-253385, a proposal is made to suppress vibration at the time of resonance by increasing the damping performance of a damper having an upward speed with respect to the rotation direction of the washing tub during dehydration. Has been.

Japanese Patent Laid-Open No. 9-253385

  However, in the case of a drum-type washing machine in which a water tub is suspended from above by a spring as in Patent Document 1 and the lower portion of the water tub is supported so as to move left and right, vibration during resonance can be effectively suppressed. However, in the case of a drum-type washing machine supported by a suspension from the lower part of the water tank, the lower part of the water tank is supported so as not to move left and right so that the water tank does not fall down. In the case of such a drum type washing machine, the movement of the water tank is different from that of Patent Document 1, and vibration during resonance cannot be effectively suppressed. Moreover, there is a risk that the vibration of the water tank is easily transmitted to the outside of the washing machine at a high rotation speed.

  Therefore, the present invention has a larger damping capacity of the damping device supporting the water tub arranged on the side where the rotation direction of the washing tub is downward when dehydrating than the damping capability of the damping device arranged on the upward side. It is characterized by doing.

  ADVANTAGE OF THE INVENTION According to this invention, the vibration at the time of dehydration of a drum type washing machine can be reduced.

  Before describing the embodiments of the present invention, the principle of the present invention will be described with reference to FIGS.

  FIG. 1 shows a simplified interior of a drum type washing machine. The water tank 2 is supported in the lower part of the water tank 2 by the suspension 4 (left side 4L, right side 4R) in the housing 1. A washing tub 3 is rotatably mounted inside the water tub 2. Dehydration is performed by rotating the water tank 2 at high speed. In FIG. 1, dewatering is performed counterclockwise. At the time of dehydration, there is clothing in the washing tub 3, but the clothing does not stick evenly to the inner surface of the washing tub 3, and a cloth slippage 8 occurs. A centrifugal force F is generated when the cloth piece 8 rotates together with the washing tub 3, and the water tub 2 is vibrated. This vibration is received by the suspension 4. The suspension 4L supports the lower left portion of the water tank 2, and the suspension 4R supports the lower right portion. The suspension 4L includes a spring 5L and a damper 6L. Similarly, the suspension 4R includes a spring 5R and a damper 6R. The dampers 6L and 6R suppress vibration at the time of resonance of the water tank 2. As the damping performance of the dampers 6L and 6R is larger, vibration at resonance can be suppressed. Moreover, even if a damper is attached to a place that is not vibrating, the vibration cannot be suppressed. If the damper is attached to a place that is greatly vibrating, the vibration is effectively suppressed.

  On the other hand, when the resonance rotational speed is exceeded and the high rotational speed is in a steady state, the vibration of the water tank 2 decreases. However, it is necessary to pay attention to vibration transmitted to the floor via the suspensions 4L, 4R, the casing 1, and the rubber legs 7. The higher the damping performance of the suspensions 4L, 4R (dampers 6L, 6R), the greater the generated damping force, and the vibration of the water tank 2 is transmitted to the floor. Therefore, it is desirable to reduce the damping performance of the suspensions 4L and 4R in order to suppress vibration transmission. Further, in the case of the same damping performance, the damping force generated is smaller as the suspension expansion and contraction is smaller, and transmission of vibration can be suppressed.

  In summary, it is desirable to arrange a damper at a position where it vibrates greatly at resonance and vibrates small at steady state. By doing in this way, it becomes possible to suppress effectively the vibration of the water tank at the time of resonance, suppressing transmission of vibration to a floor.

  Therefore, the movement of the left and right dampers will be considered with reference to FIGS. Basically, the aquarium 2 has three vibration modes: a left-right translation mode, a vertical translation mode, and a rotation mode. FIG. 2A, FIG. 3A, and FIG. 4A show water tank 2 and suspension support points P1 and P2 for each vibration mode. These vibration modes change with the rotation speed. The left / right translation mode increases (resonates) at around 150 r / min, the up / down translation mode increases at around 220 r / min, the rotation mode increases at 400 to 600 r / min, and thereafter this rotation mode remains unchanged. Vibration is getting smaller. The problem in the resonance passage is the left-right translation mode and the vertical translation mode, and the problem in steady state is the rotation mode.

First, the left-right translation mode is considered in FIG. Since the water tank 2 is supported by the points P1 and P2 located at the lower part by the two suspensions, the lower part of the water tank 2 is harder to move than the upper part. Therefore, the upper part of the water tank 2 vibrates more greatly than the lower part as shown in FIG. When the previous resonance of lateral translation mode the fabric deviation is positioned to the left, the water tank 2 is moved to the left by its centrifugal force, the supporting points P1, P2 are moved to the position of a _1, a _2. On the other hand, when the cloth piece is located on the right side, the water tank 2 is also moved to the right, and the support points P1 and P2 are moved to the positions b ₁ and b ₂ . However, at the time of resonance, the displacement is delayed by 90 ° with respect to the excitation force. Therefore, when it is counterclockwise, the water tank 2 moves to the left when the cloth piece is located below and the cloth piece is located above. Sometimes the aquarium 2 moves to the right. Moreover, since the force is generated in the downward direction when the cloth piece is on the lower side, the water tank 2 moves downward. Therefore, the water tank 2 moves in the left direction + downward direction, and the support points P1 and P2 move to the positions c ₁ and c ₂ shown in FIG. On the other hand, when the cloth piece is on the upper side, since the force is generated in the upward direction, the water tank 2 moves upward. Therefore, the water tank 2 moves in the right direction + upward direction, and the support points P1 and P2 move to positions d ₁ and d ₂ shown in FIG. Thereby supporting points P1, P2 of the suspension movable between _{c 1, c 2 ~d 1,} d 2 shown in FIG. 2 (B) in the left-right translation mode. It can be seen that the suspensions 4L and 4R expand and contract more greatly on the left side than on the right side. Therefore, the left-right translation mode can be effectively suppressed by increasing the damping performance of the left damper, that is, the damper on the side where the rotation direction is downward.

Next, consider the vertical translation mode in FIG. As shown in FIG. 3A, when the aquarium 2 is located close to the cloth piece before resonance, the aquarium 2 is moved upward by the centrifugal force, and the support points P1 and P2 are at the positions of e ₁ and e ₂ . Moving. On the contrary, when the cloth side is located below, the water tank 2 is also moved downward, and the support points P1 and P2 are moved to the positions of f ₁ and f ₂ . However, at the time of resonance, the displacement is delayed by 90 ° with respect to the excitation force. Therefore, when turning counterclockwise, the water tank 2 moves upward when the cloth piece is located on the left, and the cloth piece is located on the right. Sometimes the aquarium 2 moves down. In addition, since the force is generated in the left-right direction when the cloth piece is on the left or right, the water tank 2 vibrates left and right. As described above, the vertical resonance rotational speed is 220 r / min, and the resonance rotational speed in the left-right translation mode is 150 r / min, and therefore passes through the resonance in the left-right translation mode. Therefore, the left and right displacements are 180 ° out of phase with respect to the excitation force, so that the water tank 2 moves to the right when the cloth piece is located on the left, and the water tank 2 is located when the cloth piece is located on the right. Move to the left. As a result, the water tank 2 when the cloth piece side is on the left moves upward and to the right, and the support points P1 and P2 move to the positions g ₁ and g ₂ shown in FIG. On the contrary, when the cloth piece is on the right, the water tank 2 moves downward + to the left, and the support points P1 and P2 move to the positions h ₁ and h ₂ shown in FIG. In the vertical translation mode, the suspension support points P1 and P2 move between g ₁ , g _{2 to} h ₁ and h ₂ shown in FIG. It can be seen that the left and right suspensions 4L and 4R expand and contract more greatly on the left side than on the right side. Therefore, it is possible to effectively suppress the vertical translation mode by increasing the damping performance of the left damper, that is, the damper having the downward rotation direction.

Finally, consider the rotation mode in FIG. Before the rotation mode resonance, the water tank 2 rotates as shown in FIG. Since the center of gravity of the water tub 2 is below the center of rotation of the washing tub 3, when the cloth piece is positioned to the right, the water tank 2 receives a moment due to the centrifugal force and the water tub 2 rotates clockwise, and the support points P1 and P2 are Move to positions i ₁ and i ₂ . On the other hand, when the cloth piece is positioned to the left, the water tank 2 rotates counterclockwise, and the support points P1 and P2 move to the positions of j ₁ and j ₂ . However, at the time of resonance, the phase of the rotation is delayed by 90 ° with respect to the applied moment. Therefore, when the washing tub 3 is counterclockwise, the water tub 2 rotates clockwise when the cloth piece is positioned upward, and the water tub 2 rotates counterclockwise when the cloth piece is positioned below. Further, when the cloth piece is on the upper side or the lower side, since the force is also generated in the vertical direction, the water tank 2 vibrates in the vertical direction. As described above, the resonance rotational speed in the rotational mode is 400 to 600 r / min, and the resonant rotational speed in the vertical translation mode is 220 r / min, and therefore passes through the resonance in the vertical translation mode. Therefore, because the vertical displacement is 180 ° out of phase with respect to the excitation force, the water tank 2 moves downward when the cloth piece is positioned above, and the water tank 2 is moved when the cloth piece is located below. Move up. As a result, when the cloth piece is on the upper side, the water tank 2 moves clockwise and downward, and the support points P1 and P2 move to positions k ₁ and k ₂ shown in FIG. 4B. On the other hand, when the cloth piece is on the bottom, the water tank 2 moves counterclockwise and downward, and the support points P1 and P2 move to positions l ₁ and l ₂ shown in FIG. 4B. In the rotation mode, the suspension support points P1 and P2 move between k ₁ , k _{2 to} l ₁ and l ₂ shown in FIG. It can be seen that the left and right suspensions 41 and 42 expand and contract slightly on the left side compared to the right side. In a steady state, the magnitude of the vibration is reduced while maintaining this rotation mode. At regular times, the left and right suspensions 41 and 42 expand and contract slightly on the left side compared to the right side. Therefore, even if the damping performance of the left damper, that is, the damper whose rotation direction is downward, is increased, the transmission of vibration to the floor in a steady state is difficult to increase.

  Thus, the vibration of the water tank 2 at the time of resonance can be reduced while suppressing the transmission of vibration to the floor at the steady state by increasing the damping performance of the damper on the side where the rotation direction is downward.

  Still further, the damping device is a hydraulic damper composed of a cylinder containing at least a liquid, a rod moving in the cylinder, and a piston attached to the rod, the piston being perforated, and the washing tub The area of the hole of the piston of the hydraulic damper disposed on the downward direction side of the rotation at the time of dehydration is small in the area of the hole of the piston of the hydraulic damper disposed on the upward direction side.

  Alternatively, only the attenuation device disposed on the downward side of the rotation during the dehydration of the washing tub can change the attenuation performance from the outside of the attenuation device, and the attenuation performance is the attenuation of the attenuation device disposed on the upward side. It can be made higher than the performance.

  As described above, the movement of the damping device with the downward rotation direction of the washing tub during dehydration is larger than the movement of the upward damping device at resonance. Therefore, if the attenuation performance of the attenuation device on the side where the rotation direction is downward is higher than the attenuation performance of the attenuation device on the upward side, the water tank at the time of resonance can be effectively reduced. Also, during steady operation at high speeds, the downward movement of the damping device is smaller than the upward movement of the damping device during resonance, so that even if the damping performance is high, the generated damping force increases. It is difficult to suppress the transmission of vibration to the outside of the washing machine body.

  Examples of the present invention will be described below with reference to FIGS. FIG. 5 is a side view of the interior of the drum type washing machine of the present invention. FIG. 6 is a front view of the inside of the drum type washing machine of the present invention. FIG. 7 is an external view of a suspension combining a spring and a damper that supports the water tank. The present invention is not limited to a drum-type washing machine, but can be applied to a drum-type washing / drying machine equipped with a drying device such as a heater or a fan.

  On the front surface of the casing 1 of the washing machine, there is a laundry inlet and a door 9 is provided. The laundry is put in and out by opening and closing the door 9. In addition, a cylindrical water tank 2 is disposed inside the housing 1 and is inclined with the inlet side from 0 to 30 ° upward from the horizontal, and the inlet side is open. The opening and the opening of the water tank 2 are connected by a bellows-like rubber bellows 10 so that the laundry does not fall into the housing 1 when the laundry is put in and out. A cylindrical washing tub 3 having a large number of holes and one end opened is rotatably provided inside the water tub 2. A rotation shaft 11 is fastened to the center of the bottom surface of the washing tub 3, and the rotation shaft 11 penetrates the center of the bottom surface of the water tub 2 in a watertight manner and is rotatable. A flange 12 is fixed to the rear bottom surface of the water tub 2, and a motor 13 that rotationally drives the washing tub 3 is fixed to the flange 12. The rotating shaft 11 of the washing tub 3 is fastened to the rotating shaft of the motor 13. Thus, the washing tub 3 can be rotated both left and right in the water tub 2 by the motor 13 provided at the rear of the water tub 2, and washing, rinsing and dehydration are performed while the washing tub 3 is rotated. In addition, a fluid balancer 14 is fixed to the front portion of the washing tub 3 in order to reduce vibration during dehydration. The fluid balancer 14 has salt water in a hollow ring, and salt water gathers on the opposite side of the clothing when dehydrating, so that the clothing is offset and the vibration is reduced.

  The water tub 2 to which the washing tub 3 and the motor 13 are attached is provided with suspensions 4L and 4R extending from the lower part to the bottom surface of the housing 1. The suspensions 4 </ b> L and 4 </ b> R are attached to a range of 60 ° or less with respect to the vertical line of the water tank 2 at substantially symmetrical positions. The suspensions 4L and 4R are provided with springs 5L and 5R outside the dampers 6L and 6R, and elastically support the water tank 2.

  A weight 15 for balancing the weight is attached to the lower front part of the water tank 2. For this reason, the center of gravity of the water tub 2 is located below the rotation axis of the washing tub.

  Further, an upper spring 16 pulls the upper rear of the water tank 2 from the vicinity of the center of the inner upper surface of the housing 1, and an auxiliary spring 17 pulls the upper front of the water tank 2. The spring constants of these auxiliary springs 16 and 17 are smaller than the springs 5L and 5R provided in the dampers 6L and 6R. The spring constant of the auxiliary spring 16 is the same as or slightly larger than the spring constant of the auxiliary spring 17. The auxiliary spring 16 is longer than the auxiliary spring 17. The positions of the housings 1 to which the auxiliary springs 16 and 17 are attached are substantially the same, but are slightly shifted to the left and right to avoid contact between the springs.

  There is a water supply unit 18 at the top of the housing 1, and water used for washing and rinsing passes through a water supply port 19, a water supply valve 20, a detergent case 21, and a bellows-shaped hose 22 provided at the top of the housing 1. And poured into the water tank 2. Further, water after washing and rinsing and water at the time of dehydration are drained through a drain valve 23 and a drain hose 24 provided at the lower part of the water tank 2.

  FIG. 7 shows the appearance of the suspensions 4L and 4R. The upper ends of the dampers 6L and 6R are attached to a metal base 25 attached to the water tank 2 via a rubber bush 26. Similarly, the lower end is attached to a metal base 27 attached to the bottom of the housing 1 via a rubber bush 26. The rubber bushes 26 at both ends are sandwiched between washers 28 and tightened with nuts 29. Even if the water tank 2 is supported, it is compressed and tightened to such an extent that the rubber bush 26 is not greatly deformed. The dampers 6R and 6L are provided with springs 5L and 5R. The springs 5L and 5R are inserted between a spring receiver 31 supported by the cylinder 30 and a spring receiver 33 supported by the rod 32. The spring receiver 31 is a cylindrical metal that is slightly larger than the cylinder 30. The lower end of the spring receiver 31 is bent inward to form a bottom surface that receives the cylinder 30, and has a hole through which the rod 32 passes. Further, the upper end is opened outward and receives the upper ends of the springs 5L and 5R. The spring receiver 33 is a metal part shaped like a dish provided with a notch that can be inserted into the rod 32, and receives the lower ends of the springs 5L and 5R. In order to prevent the springs 5L and 5R from moving sideways, the hooks are raised in accordance with the outer diameters of the springs 5L and 5R.

  8 and 9 show sectional views of the dampers 6L and 6R. FIG. 10 shows a state when the damper of FIG. 9 is vibrated greatly. In these drawings, common parts are denoted by the same numbers. For parts with different specifications on the left and right dampers, suffixes L and R are appended to the number. L is a part of the left damper, and R is a part of the right damper. Although oil 34 is contained in the cylinder 30, a space is provided without filling the entire cylinder 30 with oil so that the rod 32 can enter. A piston 35 having a size substantially the same as the inner diameter of the cylinder 30 is fixed to the tip of the rod 32. The piston 35 has a plurality of small holes 36, and the oil 34 can move in the oil 34 by passing through the holes 36. If the area of the hole 36 is large, the resistance is small, and the piston 35 and the rod 32 move smoothly. Moreover, if the area of the hole 36 is narrow, resistance will be large and the movement of the piston 35 and the rod 32 will become dull. The rod 32 is provided with a flange 37 at a position below the piston 35 at a distance. A valve 38 is disposed between the piston 35 and the flange 37. The diameter of the valve 38 is a disk-like component that is smaller than the piston 35 and larger than the position where the hole 36 is provided. The valve 38 has a hole slightly larger than the diameter of the rod 32 between the piston 35 and the flange 37 in the center, and can move freely between the piston 35 and the flange 37. When the valve 38 contacts the piston 35 as shown in FIG. 10, the holes other than the hole 36a are blocked. The lower portion of the piston 35 is provided with a notch 39 in the radial direction at the position of the hole 36a, and the hole 36a is not blocked even when the valve 38 contacts the piston 35. In this state, the area of the hole 36 through which the oil 34 passes is reduced, the resistance is increased, a large damping force is easily generated, and the damping performance is high. Further, the valve 38 is preferably made of resin in order to reduce the impact caused by the collision with the piston 35 as much as possible.

  The internal movement of the dampers 6R and 6L having such a structure will be described. When the piston 32 vibrates small, the state is as shown in FIG. 9, and the valve 38 is positioned below and away from the piston 35. In such a state, the holes 36 are all present, the area of the holes is large, the resistance is small, the damping force is small, and the damping performance is low.

  Further, when the vibration of the piston 35 increases, when the damper moves in the contracting direction, the valve 38 presses against the flange 37 and all the holes 36 are opened. Further, when the damper moves in the extending direction, the valve 36 is in contact with the flange 37 when starting to move, but gradually moves upward together with the oil 34 in the cylinder 30 to move away from the flange 37, as shown in FIG. The piston 35 presses against the piston 35, and the holes 36 other than the hole 36a are closed. Therefore, in the case of a large vibration, only the hole 36a is open, the resistance is large, and high damping performance is switched. Thus, the damper has a damping performance that changes depending on the magnitude of vibration.

  Such dampers are attached to the left and right of the lower part of the water tank 2 to suppress vibration of the water tank 2. The support structure of the present invention is such that the left and right characteristics of such a damper are different. In this embodiment, the direction of rotation of the washing tub 3 during dehydration is the direction of the arrow in FIG. 6 and is counterclockwise when viewed from the front. FIG. 8 shows the damper on the side whose rotational direction is downward, that is, the left damper 6L. FIG. 9 shows a damper on the side whose rotational direction is upward, that is, a right damper 6R. Basically both have the same structure. However, the hole 36 provided in the piston 35 that determines the damping performance is different. The number of holes 36L in the left damper 6L is four, and the number of holes 36R in the right damper 6R is five. Also, the size of the hole 36 is such that the hole 36L of the left damper 6L is smaller than the hole 36R of the right damper 6R. That is, the area of the hole 36L of the left piston 35 is narrower than the area of the hole 36R of the right piston 35. In this way, the damping performance of the left damper 6L is made higher than that of the right damper 6R.

  A band 40 made of resin is attached to the outer periphery of the piston 35 of the left damper 6L so as to reduce the gap between the piston 35 and the cylinder 30. By doing in this way, circulation of the oil 34 from not the hole 36 of piston 35 but the outer periphery of piston 35 was reduced, and damping performance was made high. Further, the force that presses the inner surface of the cylinder is increased, the frictional force with respect to the operation of the piston 35 is increased, and the damping performance is further increased.

  Further, the distance LL from the piston 35 of the left damper 6L to the flange 37 is made shorter than the distance LR from the piston 35 of the right damper 6R to the flange 37. By doing in this way, the section which operates with low attenuation performance is short, the section which operates with high attenuation performance becomes long, and the attenuation performance is totally improved.

  The relationship between the strokes of the dampers 6L and 6R and the damping force will be described with reference to FIG. In particular, a description will be given of the characteristics of the damper in a resonance state having a large amplitude, specifically, in a vibration of about ± 6 to 10 mm at 3 to 4 Hz. The solid line indicates the characteristic of the left damper 6L, and the dotted line indicates the characteristic of the right damper 6R. The characteristic of the left damper 6L will be described as an example.

  A point A shown in FIG. 11 is a state in which the damper is contracted. From the state, the damping force gradually increases with the extension of the damper, the damping force is switched at the point B, and the damping force starts to increase rapidly, and is attenuated at the point C. Power is maximized. Furthermore, the damper extends, but the damping force decreases, and at point D, the damper starts to shrink. The damping force decreases from the point D, and further, the damping force in the reverse direction is generated. At the point E, the damping force in the reverse direction becomes maximum, and thereafter, the damping force in the reverse direction gradually decreases and returns to the point A. As described above, the attenuation performance is switched to two stages with the point B as a boundary.

  Compared with the right damper 6R, the left damper 6L has a smaller area of the piston hole 36 and the resin band 40 is wound to increase the first-stage damping force (damping force at point B). . Further, by shortening the distance from the piston 35 to the flange 37, the position of the point B where the damping characteristic is switched is close to the point A, and the range in which the second stage damping performance is high is widened. Further, since the area of the piston hole 36a not blocked by the valve 38 is reduced, the second-stage damping force (damping force at the point C) is also increased. Thus, the damper 6L on the left side generates a larger damping force, so that the damping performance is higher.

  When the dewatering rotation direction is counterclockwise, the damping performance of the left damper 6L is made higher than the damping performance of the right damper 6R, thereby suppressing the vibration transmitted to the floor during high rotation and suppressing the vibration of the aquarium during resonance. be able to. This is shown in FIGS. FIG. 12 shows the force transmitted to the floor at the time of high rotation when the damping performance of the left and right dampers is changed and the displacement of the water tank at the time of resonance in the left and right vibration mode near 150 r / min. Similarly, FIG. 13 shows the force transmitted to the floor at the time of high rotation when the damping performance of the damper is changed and the displacement of the water tank at the time of resonance in the vertical vibration mode near 220 r / min. In both figures, the solid line shows the case where the damping performance of the left damper 6L is changed, the dotted line shows the case where the damping performance of the right damper 6R is changed, and the broken line shows both the left and right dampers 6L and 6R. Is changed by the same amount. Basically, when the damping performance is increased, the vibration at the time of resonance is reduced and the force transmitted to the floor is increased. However, a desirable characteristic is a characteristic that reduces vibration during resonance without increasing the force transmitted to the floor. In other words, this desired characteristic is a relationship directly below as indicated by the arrows in FIGS. 12 and 13 that the relationship when the damping performance of the left damper 6L is changed is close to a desirable characteristic.

  That is, the damping characteristic is increased in order to suppress vibration at the time of resonance, but if the damping performance of the left damper 6L is increased, the increase in force transmitted to the floor can be suppressed to a low level. On the contrary, if the damping performance of the right damper 6R is increased, only the force transmitted to the floor increases, and the vibration at the time of resonance does not easily become small. Thus, in order to suppress the resonance in the left and right vibration mode and the vertical vibration mode, it is desirable to increase the damping performance of the left damper 6L. Therefore, as in the present embodiment, the vibration of the resonance is generated by making the damping performance of the left damper 6L higher than the damping performance of the right damper 6R with respect to the counterclockwise drum type washing machine that rotates counterclockwise during dehydration. Can be effectively suppressed.

  Further, it is not necessary to use the above-described means for increasing the damping performance for the left damper 6L. For example, only the piston hole 36a that is not closed by the valve 38 may be changed, and the left piston hole 36aL may be made smaller than the right piston hole 36aR.

  The left and right dampers of the present embodiment are dampers whose damping performance is switched depending on the magnitude of vibration, but may be dampers that do not have the flange 37 and the valve 38 and do not switch the damping performance.

  Further, a damper whose damping performance is switched only on the left side may be provided so as to have a large damping performance at the time of resonance, and a damper on which the damping performance without the flange 37 and the valve 38 is not switched may be provided on the right side.

  Next, FIG. 14 shows a second embodiment. The basic structure is the same as that of the first embodiment, and the damper that supports the water tank is different. In the damper of this embodiment, the left side is the same hydraulic damper as that of the first embodiment, and the right side is a friction damper. As shown in FIG. 14, the friction damper is assembled in the cylinder 41 in a state where the rod 42 and the piston 43 can move up and down. Around the piston 43, a sliding member 44 made of urethane foam, rubber, felt or the like, which is a softer material than the piston 43, is wound. The frictional force between the sliding member 44 and the inner surface of the cylinder 41 gives a damping action. Further, grease is applied to the inner surface of the sliding member 44 and the cylinder 41 so that smooth sliding can be performed. Further, a small air hole 45 is provided in the upper part of the cylinder 41 and a small air hole 46 is provided in the piston 43. This is to prevent the air in the cylinder from being compressed and expanded by the vertical movement of the piston and having a large spring action due to the air if the air in the cylinder cannot come and go with the air outside the cylinder. . Further, the damping action is obtained by the air entering and leaving the small air holes 45 and 46. Such a damper is provided on the right side to provide friction and air damping action.

  Further, the damping performance of the left hydraulic damper is made higher than that of the right friction damper. In particular, the damping force against vibration of ± 6 to 10 mm is increased at 3 to 4 Hz at the time of resonance.

  Conventionally, expensive hydraulic dampers have been used for both the left and right dampers in order to reduce vibration. However, by using a hydraulic damper on the left side and a friction damper on the right side as in this embodiment, an expensive hydraulic damper can be made an inexpensive friction damper while reducing vibration, which is cost effective. .

  The damper on the left side of the present embodiment is a hydraulic damper whose damping performance is switched depending on the magnitude of vibration, but may be a hydraulic damper that does not have a saddle or a valve and does not switch damping performance.

  Further, the right suspension may not have damping performance. However, if the aquarium is supported from the bottom with only the spring, the spring itself will fall in a direction other than the expansion and contraction direction of the spring. Therefore, in order to prevent the fall, a friction damper that hardly generates frictional force and damping force due to air is used. It is desirable.

  Next, FIG. 15 shows a third embodiment. The basic structure is the same as that of the first embodiment, and the damper that supports the water tank is different. The damper of the present embodiment is a hydraulic damper on the right side and a variable damper on the left side that can control the damping performance of the damper from the outside of the damper. The right hydraulic damper is the same as in the first embodiment. As shown in FIG. 15, the variable damper has a space in the cylinder 47 so that the rod 48 can enter, and a magnetic fluid 49 is contained therein. The magnetic fluid 49 is a mixture of a solid and a liquid in which metal particles that are magnetic substances are dispersed in a liquid at a high density. In the magnetic fluid 49, the force with which the magnetized metal particles attract each other changes depending on the magnitude of the magnetic field, and the viscosity changes. A piston 50 is fixed to the tip of the rod 48. There is a gap between the piston 50 and the inner surface of the cylinder 47. By passing the magnetic fluid 49 through the gap, the piston 50 can move in the magnetic fluid 49. If the viscosity of the magnetic fluid 49 is low, the resistance is small, the piston 50 and the rod 48 move smoothly, and the damping performance is low. Conversely, if the viscosity of the magnetic fluid 49 is high, the resistance is large and the damping performance is high. In order to control the viscosity of the magnetic fluid 49, it is necessary to change the magnetic field. A coil 51 is attached to the piston 50 in order to change the magnetic field. When a current is passed through the coil 51, a magnetic field is formed around the coil 51, the viscosity of the magnetic fluid 49 increases, and the damping performance increases. The strength of the magnetic field changes depending on the magnitude of the current flowing through the coil 51, and the attenuation performance can be controlled. A variable damper driving circuit 52 for flowing a current flowing through the coil 51 and a microcomputer 53 for instructing the magnitude of the current are mounted. The microcomputer 53 controls the current based on the number of rotations of the washing tub and the vibration amount of the water tub. Therefore, it has a washing tank rotation number detecting means 54 and a vibration detecting device 55 for detecting the vibration amount of the water tub. The vibration detection device 55 is not particularly selected from means such as water tank acceleration, displacement, damper expansion / contraction amount, motor torque fluctuation amount, and the like. Based on the control signal from the microcomputer 53, the variable damper drive circuit 52 adjusts the current supplied from the power supply 56 and supplies it to the coil 51. The microcomputer 53 also sends a control signal to the motor drive circuit 57 to adjust the current / voltage from the power source 58 and control the rotation of the motor 13. In the present embodiment, the variable damper and the motor speed are controlled by the same microcomputer 53, but different microcomputers may be used. The control of the variable damper during dehydration performed by the microcomputer 53 having such a configuration is shown in FIGS. FIG. 16 shows the control of the variable damper with respect to the rotational speed, and FIG. 17 shows the control of the variable damper with respect to the vibration of the water tank. The variable damper as shown in FIGS. 16 and 17 is controlled at predetermined time intervals during dehydration.

  Control of the variable damper with respect to the rotational speed shown in FIG. 16 will be described. After dehydration starts, damper control is started at predetermined time intervals (S1). First, the rotation speed of the washing tub is detected (S2). If the number of revolutions is less than 80 r / min (S3), it is in front of the resonance region and the vibration is small, so there is no need to increase the attenuation, so the current is turned off or the current is made smaller than at resonance (S4). Then, the damper control is finished (S5). If the rotational speed is 80 r / min or more (S3), it is next determined whether the rotational speed is less than 450 r / min (S6). If the rotational speed is less than 450 r / min, it is a resonance region and vibration tends to increase, so that the current is turned on and a large current is caused to flow through the coil 46 (S7). Then, the damper control is finished (S5). On the other hand, if the rotational speed is 450 r / min or more (S6), the vibration is reduced because it has passed through the resonance region, so the current is turned off or the current is made smaller than at the time of resonance (S8). Then, the damper control is finished (S5). That is, the microcomputer 48 controls the current to be turned on or increased so that a large current flows through the coil 46 while the water tub whose rotation speed is 80 to 450 r / min is resonating. A large current increases damping performance and suppresses vibration during resonance. In addition, the microcomputer 48 makes the current OFF or smaller than the resonance at a rotation speed range of 0 to 80 r / min, 450 r / min or more other than the resonance rotation speed range, and does not pass the current through the coil or has a smaller current than at the resonance time. Control to flow. Since the vibration of the aquarium is small, the damping performance is lowered to prevent the vibration of the aquarium from being transmitted to the floor.

  Next, the control of the variable damper with respect to the vibration amount of the water tank shown in FIG. 17 will be described. After dehydration starts, damper control is started at predetermined time intervals (S11). The microcomputer 48 detects the vibration amount of the water tank (S12). If the vibration amount of the water tank is smaller than the predetermined threshold value V0 (S13), it is not necessary to suppress the vibration, so the current is turned off or a small current is passed. (S14). Then, the damper control is finished (S15). On the other hand, when the vibration amount of the water tank is equal to or greater than a certain threshold value V0 (S13), it is determined that the vibration is large, and the current is turned on or controlled to flow a large current (S16). By doing so, damping performance is improved and vibration is suppressed. Further, the vibration amount of the water tank is compared with a predetermined threshold value V1 (S17). If the vibration is smaller than V1, the damper control is terminated as it is (S15). Conversely, when the vibration is larger than V1, it is determined that the vibration is abnormally large, and the motor drive circuit is controlled to reduce the rotation speed or stop the rotation (S18), and the damper control is terminated (S15). .

  As described above, by using the variable damper, it is possible to increase the damping performance only when necessary. In addition, if the vibration of the outer tub is likely to increase, the vibration can be predicted, the damping performance can be increased in advance, and the increase in vibration can be further prevented. By applying the high damping performance to the left damper, the vibration of the outer tub can be effectively suppressed. Further, when not necessary, the damping performance can be lowered, and the transmission of vibrations to the floor can be further reduced.

  In this embodiment, both the control based on the rotational speed and the control based on the vibration amount are included, but only one of them may be used.

  Further, with respect to the variable damper used on the left side of the present embodiment, the damping performance when a current is passed through the coil of the variable damper is made higher than that of the right hydraulic damper. In particular, the damping force against vibration of ± 6 to 10 mm is increased at 3 to 4 Hz at the time of resonance. In this embodiment, the right damper uses a hydraulic damper whose damping performance varies depending on the magnitude of vibration. However, since it does not need to be larger than the damping performance of the left variable damper, the hydraulic damper whose damping performance does not change. However, a friction damper may be used. In the present embodiment, the left damper is a variable damper using a magnetic fluid, but the means is not particularly limited as long as the damper can adjust the damping performance of the damper from the outside. In addition, the damper on the left side of the present embodiment controls the vibration by indirectly changing the force on the water tank by changing the damping performance, but it is like an actuator that actively generates force on the water tank. It is also possible to use a damper that controls vibration.

  As described above, the vibration at the time of resonance is effectively suppressed by making the left-side damping performance higher than the right-side damping performance with respect to the counterclockwise drum type washing machine that rotates counterclockwise during dehydration.

The front view which shows the inside of a drum type washing machine. The figure showing the left-right vibration mode of an aquarium. The figure showing the vertical vibration mode of a water tank. The figure showing the rotation mode of an aquarium. The side view which shows the inside of an Example. The front view which shows the inside of an Example. FIG. The perspective view inside a damper. The perspective view inside a damper. The perspective view inside a damper. The characteristic diagram of a damper. The relationship between the force transmitted to the floor and the lateral displacement. The relationship between the force transmitted to the floor and the vertical displacement. The perspective view inside a friction damper. The perspective view inside a variable damper. Flow of damper control by rotation speed. Flow of damper control by vibration amount.

Claims (4)

A casing of the washing machine, a water tub provided therein, a washing tub rotatably attached to the water tub, and the rotation direction of the washing tub with respect to the dehydration rotation of the washing tub are the upper side and the lower side In a drum-type washing machine provided with water tank support means attached to the lower part of the water tank,
Two said water tank support means are arrange | positioned so that the rotating shaft of the said washing tub may be pinched | interposed, It is the one said water tank support means, Comprising: The said water tank support from which the rotation direction of the said washing tub at the time of dehydration becomes a lower side A drum-type washing machine characterized in that the damping performance of the means is the other water tank support means, which is higher than the attenuation performance of the water tank support means in which the rotating direction of the washing machine during dehydration is on the upper side. The water tank support means damping device is a hydraulic damper composed of a cylinder containing at least a liquid, a rod moving in the cylinder, and a piston attached to the rod, and the piston has a hole, The area of the hole of the piston of the hydraulic damper disposed on the side where the rotation direction of the washing tub is downward when dewatering is smaller than the area of the hole of the piston of the hydraulic damper disposed on the upward side The drum type washing machine according to claim 1 . The attenuation device of the water tank support means can change the attenuation performance from the outside of the attenuation device only in the attenuation device arranged on the side where the rotation direction of the washing tub is downward when dewatering, and the attenuation performance is 2. The drum type washing machine according to claim 1 , wherein the damping performance of the damping device arranged on the upward side can be made higher . 2. The side of the washing tub in which the rotation direction of the washing tub is upward is supported by a damping device that has no damping performance or little damping performance and an elastic holding means . Drum type washing machine.

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