JP2008125805A - Drum type washing machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a compact drum type washing machine which generates less vibration and less noise. <P>SOLUTION: The drum type washing machine comprises a water tub 3 supported at least inside a washing machine case 1 by a spring and a damper 7, a rotatable washing tub 4 installed inside the water tub 3 for storing laundry, and a motor 5 for driving and rotating the washing tub 4. The damper 7 has characteristics of switching to a greater damping force only when the water tub 3 moves upward by the magnitude of vibration of the water tub 3 so as to suppress excessive vibration. In the case of small vibration, the damping force is decreased so as to decrease transmission of the vibration. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a vibration isolator 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. It is necessary to remove moisture from the clothes as much as possible before drying and drying the clothes after washing. 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 to reduce vibrations and allow centrifugal dehydration in the proper state.

  If the spring constant of the spring is reduced, it is possible to make it difficult to transmit the vibration of the water tank to the washing machine casing. However, if the spring constant is reduced, the clothes will sink greatly when clothes or washing water is added, and the spring will be in close contact. If it does so, the vibration at the time of washing cannot be relieved, the burden to a spring will become large, and deterioration will progress.

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

JP 2001-212395 A

  In the case of a drum-type washing machine as in Patent Document 1, the washing tub is supported by a spring and an oil damper from below. Valve bodies for closing orifices provided in the piston are arranged on both sides of the piston of the oil damper. When vibration such as at the time of resonance is large, the piston moves so as to contact the valve body. Since the orifice is blocked by the valve body and the damping force becomes large, vibration can be suppressed and the valve can be started smoothly. Further, during high-speed rotation, vibration is small, the piston does not move to the valve body, all the orifices are present, and the damping force is small. For this reason, vibration is not significantly transmitted to the washing machine casing, and the vibration-proof characteristic is obtained.

  However, a gap is required for the two valve bodies to float, the damper becomes long, and it is difficult to make a compact drum type washing machine. Moreover, there is a possibility that a collision sound is generated when the valve body and the piston come into contact with each other.

  Therefore, when the expansion and contraction of the damper becomes longer than a predetermined length due to the vibration of the water tank, the damper is mounted so that the damping performance is switched so that the damping force is increased only in the extending direction.

  Next, in order to reduce the spring constant and reduce the vibration, the spring supporting the water tank is disposed outside the damper, and the damper is compressed even when the damper is extended to the maximum. Is attached.

  Furthermore, the damper, whose damping performance is switched so that the damping force increases only in the extending direction, has a damping performance at a position extending 8 mm or more from the position where it begins to stretch during vibration so that the impact sound during switching does not last for a long time. Begins to switch.

  The damper is a structure in which a piston provided with a plurality of small holes for circulating oil in a cylinder in which oil is contained moves, in order to reduce the impact when switching and to make low-noise dehydration activation, The total area of the holes is 5% or less of the area of the piston.

  The spring constant can be reduced without increasing the size of the casing of the drum type washing machine, and the vibration isolation performance can be improved. Further, by mounting a damper that switches so that the damping force increases only in the extension direction of the damper when the vibration becomes larger than a predetermined magnitude, a large vibration at the time of resonance can be suppressed with a large damping force. Further, in a small vibration state at high rotation, the damping force can be reduced to suppress the transmission of vibration to the housing and the floor. In addition, it is possible to reduce the impact sound generated when switching the damping force and to dehydrate gently.

  Examples will be described below.

  Examples of the present invention will be described below with reference to FIGS. FIG. 1 is a side view of the interior of the drum type washing machine of the present invention. FIG. 2 is a front view of the inside of the drum type washing machine of the present invention. FIG. 3 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 2 is provided. The laundry is put in and out by opening and closing the door 2. In addition, a cylindrical water tank 3 is disposed on the inner side of the housing 1 so as to be inclined with the inlet side from 0 to 30 ° upward from the horizontal and opened on the inlet side. The opening and the opening of the water tank 3 are connected by a bellows-like rubber bellows 6 so that the laundry does not fall into the housing 1 when the laundry is put in and out. Inside the water tub 3, a cylindrical washing tub 4 having a large number of holes and one end opened is rotatably provided. A rotating shaft 9 is fastened to the center of the bottom surface of the washing tub 4, and the rotating shaft 9 penetrates the center of the bottom surface of the water tub 3 in a watertight manner and is rotatable. A flange 8 is fixed to the rear bottom surface of the water tub 3, and a motor 5 that rotationally drives the washing tub 4 is fixed to the flange 8. The rotating shaft 9 of the washing tub 4 is fastened to the rotating shaft of the motor 5. Thus, the washing tub 4 can be rotated around the left and right sides of the water tub 3 by the motor 5 provided at the rear of the water tub 3, and washing, rinsing and dehydration are performed while the washing tub 4 is rotated. In addition, a fluid balancer 10 is fixed to the front portion of the washing tub 4 in order to reduce vibration during dehydration. In the fluid balancer 10, salt water is contained 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.

  In the water tub 3 to which the washing tub 4 and the motor 5 are attached, a damper 7 is attached from the bottom surface of the housing 1 to the lower part of the water tub 3. A spring 16 is disposed outside the damper 7 to elastically support the water tank 3. The dampers 7 are attached at substantially symmetrical positions, and the two tanks support the water tank 3.

  Further, the upper spring of the water tank 3 is pulled by the auxiliary spring 17 and the upper front of the water tank 3 is pulled by the auxiliary spring 17 from near the center of the inner upper surface of the housing 1. The spring constants of these auxiliary springs 17 and 18 are smaller than that of the spring 16 provided in the damper 7. The spring constant of the auxiliary spring 17 is the same as or slightly larger than the spring constant of the auxiliary spring 18. The auxiliary spring 17 is longer than the auxiliary spring 18. The position of the casing 1 to which the auxiliary springs 17 and 18 are attached is substantially the same position, but is slightly shifted left and right to avoid contact between the springs.

  A water supply unit 11 is provided at the top of the housing 1, and water used for washing and rinsing passes through a water supply port 12, a water supply valve 13, a detergent case 14, and a bellows-shaped hose 15 provided at the top of the housing 1. And poured into the water tank 3. Further, water after washing and rinsing and water at the time of dehydration are drained through a drain valve 19 and a drain hose 20 provided at the lower part of the water tank 3.

  As shown in the front view of FIG. 2, the lower portion of the housing 1 is narrower than the center portion so that it can be easily installed on a waterproof pan in a home. Therefore, the left and right dampers 7 cannot be widely attached to the bottom surface of the housing 1, and are attached at an interval narrower than the inner diameter of the washing tub 4. The damper 7 is attached with an inclination of about 5 degrees toward the inside of the water tank 3. Therefore, the attachment position of the damper 7 to the water tank 3 is in a range below 45 degrees with respect to the vertical line of the water tank 3 below the side surface of the water tank 3. Therefore, the damper 7 is attached to the lower side of the water tank 3, and it is desirable that the length of the damper is short so as not to increase the height of the casing.

  FIG. 3 shows the appearance of the damper 7. The upper end of the damper 7 is attached to a metal base 21 attached to the water tank 3 via a rubber bush 23. Similarly, the lower end is attached to a metal base 22 attached to the bottom of the housing 1 via a rubber bush 23. The rubber bushes 23 at both ends are sandwiched between washers 24 and tightened with nuts 25. The rubber bush 23 is compressed and tightened to such an extent that the rubber bush 23 is not greatly deformed even when the water tank 3 in a state where no clothing or washing water is put is supported. The damper 17 is provided with a spring 16. The spring 16 is inserted between a spring receiver 27 supported by the cylinder 26 and a spring receiver 29 supported by the rod 28. The spring receiver 27 is a cylindrical metal that is slightly larger than the cylinder 26. The lower end of the spring receiver 27 is bent inward to form a bottom surface that receives the cylinder 26, and has a hole through which the rod 28 passes. The upper end is open to the outside and receives the upper end of the spring 16. The spring receiver 29 is a metal part shaped like a dish provided with a notch that can be inserted into the rod 28, and receives the lower end of the spring 16. In order to prevent the spring 16 from moving sideways, the ridges are raised in accordance with the outer diameter of the spring 16. The spring 16 is preferably a spring having a shape in which the center swells from both ends. By narrowing the both ends, the lateral movement of the spring 16 can be eliminated, and at the same time, the spring force becomes a characteristic immediately before the close contact occurs, and the close contact of the spring 16 is less likely to occur.

  In such a drum-type washing machine, a compact and excellent vibration-proof performance is provided.

  In order to improve the anti-vibration performance, the spring constant of the spring 16 is lowered. When the spring constant is lowered, the force generated by the vibration of the water tank 3 is reduced, and the vibration of the casing 1 and the floor is reduced. However, when clothes and washing water are added, the sinking becomes large, and the spring 16 comes into close contact, or the damper 7 is contracted to the minimum length. If the spring 16 is in close contact, the deterioration of the spring 16 proceeds, which is not preferable. Further, when the damper 7 is contracted to the minimum length, a collision occurs inside the damper 7 and the damper 7 is broken. In order to suppress this, it is necessary to lengthen the free length of the spring 16 and the damper 7. However, if the damper 7 is lengthened, the position of the water tank 3 is increased and cannot be made compact. It is necessary to attach a spring 16 having a long free length without changing the length of the damper 7. Therefore, as shown in FIG. 4, the free-length spring 16 of FIG. 4A is compressed and assembled into the damper 7 as shown in FIG. However, when supporting an unloaded water tub 3, washing tub 4, motor 5 etc. that does not contain clothes or washing water, the length can be further subtracted from FIG. 4 (b) as shown in FIG. 4 (c). Compress and install in damper 7. By doing so, the spring constant of the spring 16 can be lowered and the vibration can be reduced without changing the length of the damper 7.

  However, if the spring 16 is compressed and attached, it can vibrate only up to FIG. 4B when the water tank 3 moves upward due to vibration. If it is attached without being compressed, it can vibrate to the position of FIG. Therefore, it is necessary to reduce the vibration of the water tank 3. In particular, it is necessary to reduce the upward vibration of the water tank 3.

Therefore, a damper 7 is attached to suppress the movement of the water tank 3 when it moves upward. FIG. 5 shows a cross-sectional view of the damper 7. A space is provided in the cylinder 26 so that the rod 28 can enter, and oil 30 is contained. A piston 32 having a size substantially the same as the inner diameter of the cylinder 28 is fixed to the tip of the rod 28. The piston 32 has a plurality of small holes 31, and the oil 30 can move in the oil 30 through the holes 31. If the area of the hole 31 is large, the resistance is small and the piston 32 and the rod 28 move smoothly. Moreover, if the area of the hole 31 is narrow, resistance will be large and the movement of the piston 32 and the rod 28 will become dull. The rod 28 is provided with a flange 34 at a position below the piston 32 at a distance. A valve 33 is arranged between the piston 32 and the flange 34. The valve 33 is a disk-shaped component that is smaller than the piston 32 and larger than the position where the hole 31 is provided. The valve 33 has a hole slightly larger than the diameter of the rod 28 between the piston 32 and the flange 34 in the center, and can move freely between the piston 32 and the flange 34. As shown in FIG. 6, when the valve 33 contacts the piston 32, the holes other than the hole 31a are blocked. The lower portion of the piston 32 is provided with a notch 35 in the radial direction at the position of the hole 31a, and the hole 31a is not blocked even if the valve 33 contacts the piston 32. In this state, the area of the hole 31 through which the oil passes is reduced, the resistance is increased, and a large damping force is generated. The valve 33 is preferably made of resin in order to reduce the impact caused by the collision with the piston 32 as much as possible.

  The internal movement of the damper 7 having such a structure will be described. When the piston 32 vibrates slightly, the state is as shown in FIG. 5, and the valve 33 is positioned below and away from the piston 32. In such a state, the holes 31 are all present, the area of the holes is large, the resistance is small, and the damping force is small.

  Further, when the vibration of the piston 32 increases, when the damper moves in the contracting direction, the valve 33 presses against the flange 34 and all the holes 31 are opened. Further, when the damper moves in the extending direction, the valve 33 is in contact with the flange 34 when starting to move, but gradually moves upward together with the oil 30 in the cylinder 28 to move away from the flange 34, as shown in FIG. The piston 32 hits against the piston 32 and the holes 31 other than the holes 31a are closed. Therefore, in the case of a large vibration, the damping force is small in the direction in which the damper 7 is contracted, but the damping force is initially small in the extending direction, but the damping force is switched greatly when a predetermined amount of movement is reached. However, since the valve 33 is affected by the movement of the oil 30, even if the piston 32 moves in the cylinder, the distance obtained by subtracting the thickness of the valve 33 from the gap between the piston 32 and the flange 34 is pressed against the valve 33. Instead, the piston 32 will not be pressed unless it moves more than that distance.

  By supporting the water tank 3 with the damper 7 having such a structure, the damping force can be increased with respect to the upward vibration of the water tank 3, so that the vibration can be reduced. Therefore, it is possible to solve the reduction in the amount of vibration in the upward direction, which is a problem caused by attaching the spring 16 having a low spring constant in a compressed state. In addition, there is a space where the clothes and washing water can sink in the downward direction of the water tank 3, which is often larger than the upward space. Thus, even in a drum type washing machine in which the space above the water tank 3 is narrow, the direction in which the vibration of the water tank 3 should be suppressed is the upward direction. It is desirable to support the damper with the damper 7 that increases the damping force against the upward vibration because the upward vibration can be reduced. Further, by simply supporting the damper 7, the gap between the upper portion of the water tank 3 and the housing 1 can be narrowed, and the size can be reduced.

  However, when using a damper that can switch the damping force to both sides as in Patent Document 1, it is necessary to extend a rod having a flange at the tip of the piston 32, the structure becomes complicated, and the damper itself It becomes long and cannot be made compact. Therefore, when vibration is large, it is more effective to use a damper that switches to a large damping force only in the extension direction and suppresses vibration in the extension direction.

  Next, the relationship between the stroke of the damper 7 and the damping force will be described. In particular, the characteristics of the damper in a resonance state with a large amplitude will be described. Since the magnitude of vibration differs depending on the amount of unbalance generated in the washing tub, let us consider the vibration at resonance when the vibration during dehydration steady rotation generates an unbalance of 4 to 5 mm in both amplitudes. The amount of unbalance that causes this magnitude of vibration is relatively large, and in the case of a washing tub having a weight of a supported part such as a washing tub and a water tub of 45 kg and φ500 mm, if a fluid balancer is not taken into consideration, 360 to 360 This corresponds to an unbalance amount of 450 g. FIG. 7 shows the relationship between the stroke of the damper 7 and the damping force during resonance in such an unbalanced state. The resonance frequency is 3 to 4 Hz, and considering the downsizing, the stroke of the damper 7 at the time of resonance is assumed to be slightly less than 15 to 20 mm.

  A point A shown in FIG. 7 is a state in which the damper 7 is contracted. From this state, the damping force gradually increases with the extension of the damper 7, the damping force is switched at the point B, and the damping force starts to increase rapidly. The maximum damping force. 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. In this way, the attenuation performance is switched in two stages and switched at point B.

  Although the characteristics shown in FIG. 7 are desirable, if the damping force switching position (point B) and the first-stage damping force (difference between the damping force at point B and point E) are not appropriate, the piston 32 and the valve 33 are switched at the time of switching. Come into strong contact, and impact noise is generated from the washing tub 4 and the bottom of the housing 1. This is shown in FIG. FIG. 8A shows the rotation speed near resonance at the time of dehydration start, and FIG. 8B shows the acceleration of the base 21 to which the damper 7 is attached. It can be seen that a large impact is generated in the resonance region of FIG. Moreover, an impact is also seen before the resonance region. These impacts are transmitted to the washing tub 4 and the bottom of the housing 1 to generate impact sounds.

  First, the damping force switching position (point B) was examined. FIG. 9 shows the relationship between the distance to the switching position (distance between AB) and the number of occurrences of impact as shown in FIG. From FIG. 9, it can be seen that the number of impacts suddenly increases when the distance is 7 mm or less. The distance to the switching position in this experiment is larger than the vibration at the time of high-speed rotation of dehydration and does not collide at the time of steady dehydration. However, as shown in FIG. 8B, the piston 32 and the valve 33 repeatedly collide at the start of dehydration outside the resonance region, so that an impact sound continues to be generated for a long time, so that many impacts are generated. Therefore, the relationship with the number of occurrences of impacts outside the resonance region is shown in FIG. From FIG. 10, it can be seen that the impact is not generated in the case of 8 mm or more. That is, if the distance to the damping force switching position is 8 mm or more, the generation of the collision sound can be suppressed only in a short time in the resonance region. In order not to generate a collision sound for a long time, it is necessary to provide a distance of 8 mm or more from the position where the damper 7 starts to extend until the damping force is switched in the characteristic diagram of the damper 7 in FIG. However, as described above, since the valve 33 is affected by the movement of the oil 30, the gap with the piston 32 needs to be 8 mm or less in order to set the distance at which the damping force is switched to 8 mm. Further, if there are valves (valve elements) on both sides as in Patent Document 1, the number of collisions increases, which is not desirable in terms of noise reduction.

Next, it is considered that the piston 32 and the valve 33 do not collide suddenly. Therefore, the total area of the holes 31 provided in the piston 32 was examined. FIG. 11 shows the relationship between the ratio of the total area of the holes 31 to the pressure receiving area of the piston and the number of shocks generated in the resonance region. FIG. 12 shows the relationship between the ratio of the total area of the holes 31 to the pressure receiving area of the piston and the maximum acceleration of the base 21.

  From FIG. 11, it can be seen that when the ratio of the total area of the holes 31 to the pressure receiving area of the piston is 5% or less, no impact is generated, but when the ratio exceeds 5%, a collision occurs. Similarly, FIG. 12 shows that the maximum acceleration of the base 21 increases when the ratio of the total area of the holes 31 to the pressure receiving area of the piston exceeds 5%. Therefore, the total area of the holes 31 provided in the piston is 5% or less of the pressure receiving area of the piston.

  This is considered to be because if the area of the hole 31 provided in the piston 32 is narrow, the oil 30 hardly flows, and the oil 30 itself becomes a cushioning material before contacting the valve 33. In addition, it is considered that the piston 32 can operate stably and can be switched smoothly because the damping force when switching is increased. FIG. 13 shows the relationship between the ratio of the total area of the holes 31 to the pressure receiving area of the piston and the first-stage damping force (point A and point E). FIG. 14 shows the relationship between the first-stage damping force and the maximum acceleration value of the base 21. As shown in FIG. 13, it can be seen that if the area of the hole 31 is reduced, the first-stage damping force is increased. As can be seen from the relational expression between the damping force and the speed of the cylindrical diaphragm shown in (Equation 1), at the same speed, the damping force decreases in inverse proportion to the square of the area ratio.

F = 8 μlcv / (a / A) ^ 2 (Equation 1)
F: Damping force μ: Viscosity l: Length of cylindrical diaphragm c: Coefficient v: Speed
a: Area of the throttle A: Area of the piston Further, it can be seen from FIG. 14 that the maximum acceleration of the base 21 increases as the first-stage damping force decreases. By increasing the first stage damping force, the impact of the base 21 can be reduced. It can be seen that a damping force of 34 N or more is necessary to suppress the impact sound. In order to stably realize the damping force necessary to prevent the generation of impact sound, the total area of the holes 31 needs to be 5% or less of the pressure receiving area of the piston. Therefore, the piston 32 is provided with the holes 31 in which the total area of the holes 31 is 5% or less with respect to the pressure receiving area of the piston.

  As described above, the drum type washing machine of the present invention that is compact and has low vibration and low noise reduces the spring constant by providing the spring 16 in the compressed state even when the damper 7 is fully extended. Reduce vibration transmission. Furthermore, excessive vibration is suppressed by the damper 7 having the characteristic that the damping force is switched only in the extension direction depending on the magnitude of the vibration, and at the same time, the damping force is reduced for small vibrations to reduce the transmission of vibration. Further, the damper 7 is switched to a large damping force at a position where it has oscillated 8 mm or more from the beginning of extension, thereby preventing many contact between the piston 32 and the valve 33 and reducing noise. Further, the total area of the holes 31 provided in the piston is 5% or less with respect to the pressure receiving area of the piston, so that the impact at the time of contact between the piston 32 and the valve 34 is reduced, the impact noise is reduced, and the noise is reduced. .

The side view which shows the inside of an Example. The front view which shows the inside of an Example. FIG. The figure showing the attachment state of a spring. The perspective view inside a damper. The perspective view inside a damper. The characteristic diagram of a damper. The figure which shows the impact which generate | occur | produces at the time of switching. Relationship between switching position and number of shock occurrences. The relationship between the switching position and the number of shock occurrences outside the resonance range. The relationship between the piston hole area ratio and the number of impacts. Relationship between piston hole area ratio and base maximum acceleration. Relationship between piston hole area ratio and first-stage damping force. The relationship between the first stage damping force and the base maximum acceleration.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Case 2 Door 3 Water tank 4 Washing tank 5 Motor 6 Bellows 7 Damper 8 Flange 9 Rotating shaft 10 Fluid balancer 11 Water supply unit 12 Water supply port 13 Water supply valve 14 Detergent case 15 Hose 16 Spring 17, 18 Auxiliary spring 19 Drain valve 20 Drain Hose 21, 22 Base 23 Rubber bush 24 Washer 25 Nut 26 Cylinder 27, 29 Spring receiver 28 Rod 30 Oil 31 Hole 32 Piston 33 Valve 34 鍔

Claims (4)

A drum-type laundry comprising a water tub supported by a spring and a damper in a washing machine casing, a washing tub rotatably provided in the water tub and containing laundry, and a motor for rotationally driving the washing tub In the machine
The drum type washing machine according to claim 1, wherein when the damper expands and contracts more than a predetermined length due to vibration of the water tank, the damping performance is switched so that the damping force is increased only when the water tank is moving upward.   The drum type washing machine according to claim 1, wherein the spring supporting the water tank is attached to the damper in a compressed state even when the damper is extended to the maximum. Machine.   The drum type washing machine according to claim 1 or 2, wherein the damper whose damping performance is switched so that the damping force is increased only in the extending direction starts to switch the damping performance at a position extending 8 mm or more from a position at which the damping starts. Drum-type washing machine characterized by   The drum type washing machine according to claim 1 or 2, wherein the damper has a structure in which a piston having a plurality of small holes moves in a cylinder in which oil is contained, and a total area of the holes is calculated as follows. A drum type washing machine characterized in that the area is 5% or less of the area of the piston.

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