JP2005274443A - Vibration detecting mechanism and method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a technique for detecting effectively abnormal vibration of a dewatering tank of a washing machine in a dewatering apparatus showing different vibrating modes depending on rotational frequencies. <P>SOLUTION: Vibration of the dewatering tank 108 of washing machine 101 is detected by a three-dimensional acceleration sensor 117 loaded on the outer tank 105. From among outputs from the three-dimensions acceleration sensor 117, the detected acceleration signals along the X-axis are amplified by the magnification system with large amplification factors and the detected acceleration signals along the Z-axis are amplified by the magnification system with small amplification factors. Therefore, detection sensitivity to transverse vibration of the dewatering tank 108 of relatively low acceleration is enhanced, while for the signals of high level from the acceleration sensor of longitudinal vibration of the dewatering tank 108 with relatively large the detecting property is assured without saturation. Thus, the dynamic ranges detecting the vibration of the dewatering tack 108 are assured and vibration of the dewatering tank 108 can be detected efficiently. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an invention for detecting abnormal vibration during dehydration in a dehydrating apparatus for dehydrating washed clothes and the like.

  In a dehydrator that dehydrates laundry by centrifugal force following the rotation of the dehydration tank, if there is uneven distribution of the laundry in the dehydration tank or the weight distribution of the laundry in the dehydration tank, abnormal vibration will occur in the dehydration tank during dehydration. May occur.

  This abnormal vibration causes inconveniences such as generation of noise, movement of the washing machine, and failure of the washing machine. Therefore, a configuration is proposed in which it is detected at an early stage and control is performed such as reducing the rotation speed of the dewatering tank. Has been. These techniques are described in Patent Documents 1 to 3, for example.

Japanese Patent Laid-Open No. 06-282 Japanese Patent Laid-Open No. 11-169581 JP 2003-71180 A

  The vibration of the dehydration tank is not the same as the vibration at the time of low-speed rotation at the start of rotation and the vibration at a stage when a certain amount of time has elapsed from the start of rotation. Therefore, an optimum vibration detecting means corresponding to the state of vibration is required. That is, since the vibration mode differs depending on the rotation speed of the dehydration tank, a vibration detection technique suitable for the vibration mode is required.

  Moreover, if the detection of abnormal vibrations in the dewatering tank is too sensitive, it becomes a washing machine in which the dewatering operation is frequently stopped, which is not preferable because of poor usability. On the other hand, if the ability to detect abnormal vibration is low, abnormal noise and a decrease in product life due to abnormal vibration are likely to occur, which is also not preferable. In this regard, in the conventional technique, since vibration corresponding to the vibration mode of the dewatering tank is not detected, vibration of the dewatering tank cannot be detected effectively.

  An object of this invention is to provide the technique which detects the abnormal vibration in a dehydration apparatus which shows the vibration mode which changes with rotation speed effectively.

  The vibration detection mechanism of the present invention includes an acceleration sensor that detects acceleration in a first axis direction and acceleration in a second axis direction orthogonal to the first axis, and first vibration in the first axis direction. Mode and a second vibration mode different from the first vibration mode in the second axial direction, the vibration member detecting vibration by the acceleration sensor, and the first vibration from the acceleration sensor Signal processing that applies first processing to the acceleration detection signal in the axial direction, and applies second processing different from the first processing to the acceleration detection signal in the second axial direction from the acceleration sensor. And a device.

  The present invention is applied to, for example, a mechanism for detecting the vibration of a member that vibrates with anisotropy such that the vibration mode in the vertical direction and the vibration mode in the horizontal direction are different. According to the present invention, since optimum processing corresponding to different vibration modes can be performed on the output of the acceleration sensor (acceleration detection output) for detecting each vibration mode, vibration is effectively detected. be able to.

  For example, consider a case where a cylindrical object is rotated about the axis of the cylinder. In this case, the cylinder vibrates during rotation due to weight imbalance, bearing backlash, and the like. At this time, the vibration mode in the axial direction of the cylinder is different from the vibration mode in the direction orthogonal to the axis. Here, the vibration mode refers to the state of vibration or the type of vibration.

  In order to detect the vibration of the cylinder, for example, an acceleration sensor may be fixed to the bearing, and the change in acceleration in the axial direction and the change in acceleration in the direction orthogonal to the axial direction may be detected. Since the modes are different, the output of the acceleration sensor in the two directions is a different form of signal. In the present invention, processing suitable for the different vibration modes is added to the output of the acceleration sensor that detects vibrations of different modes, thereby increasing the vibration detection efficiency.

  In the above invention, it is preferable that the vibrating member is a dewatering tub of a washing machine, and the second axial direction substantially coincides with the rotational axis direction of the dewatering tub. In other words, it is preferable to apply the vibration detection mechanism to a mechanism for detecting the vibration of the dewatering tub of the washing machine. Note that the second axial direction and the rotation axis direction of the dehydration tank need only coincide with each other to the extent that vibration in the rotation axis direction of the dehydration tank can be detected.

  When the dewatering tank rotates, a vibration mode in the rotation axis direction and a vibration mode in a direction perpendicular to the rotation axis appear. For example, a general dewatering tank arranged in a vertical shape rotates with a motion such that the upper part of the dewatering tank swings its head at the start of rotation with a relatively long slow cycle. This motion of shaking the head is periodic and a kind of vibration. This vibration mode is detected as a vibration characterized by an amplitude in the horizontal direction (that is, a direction perpendicular to the rotation axis). For convenience, this vibration is referred to as lateral vibration.

  As the rotational speed increases, the rotational moment increases, so that the movement of shaking the head is reduced, and instead, a vibration mode in which the entire dehydration tank vibrates in small increments appears. This vibration mode is detected as vibration characterized by the amplitude in the direction of the rotation axis of the dehydration tank. For convenience, this vibration is referred to as longitudinal vibration.

  Lateral vibration is vibration that appears when the dewatering tank is rotating at a low speed. However, since the cycle is long, the acceleration is not so large, and therefore the output of the acceleration sensor that detects the lateral vibration has a relatively small value. On the other hand, the longitudinal vibration is a vibration that appears when the dehydration tank is rotating at high speed, so the amplitude is relatively small but the acceleration accompanying the vibration is large, and the output from the acceleration sensor is a relatively large value. It becomes.

  As described above, in the aspect in which the present invention is applied to the dewatering tub of the washing machine, the vibration mechanism of the lateral vibration and the vertical vibration is different. Therefore, in order to accurately detect the vibration of the dewatering tub, an acceleration sensor that detects the lateral vibration is used. It is important to separate the handling of the output from the handling of the output of the acceleration sensor that detects longitudinal vibration.

  In the above-described aspect, the process for the output of the acceleration sensor that detects the lateral vibration and the process for the output of the acceleration sensor that detects the vertical vibration can be made suitable for the form of each signal. For this reason, the vibration of the dewatering tank can be accurately detected, and the safety device can be effectively controlled by detecting the abnormal vibration of the dewatering tank.

  In the aspect in which the present invention is applied to the laundry dehydrating apparatus described above, the first and second processes are amplification processes for amplifying the acceleration detection signal. From the amplification factor in the second process, It is preferable that the amplification factor is larger.

  According to this aspect, it is possible to relatively increase the amplification factor of the detection signal of the lateral vibration having a relatively small output voltage from the acceleration sensor, thereby increasing the detection sensitivity. Further, the amplification factor of the longitudinal vibration detection signal having a relatively large output voltage from the acceleration sensor can be made relatively small, thereby increasing the saturation point of the amplification circuit and ensuring a wide detection dynamic range.

  As described above, when the dehydrating tank is operated, the transverse vibration is dominant at the initial stage, and the longitudinal vibration becomes dominant as the rotational speed increases. At this time, the acceleration according to the lateral vibration is relatively small, and the acceleration according to the longitudinal vibration is relatively large. Therefore, the output voltage of the acceleration sensor that detects lateral vibration is relatively small, whereas the output voltage of the acceleration sensor that detects longitudinal vibration is relatively large.

  In general, the dynamic range of a detection device that handles the output of an acceleration sensor is limited. Therefore, in this embodiment, in order to correct the imbalance of the output voltage between the acceleration sensors, the amplification factor of the acceleration detection signal in each vibration mode is intentionally set to a different value. Thereby, a large detection dynamic range for detecting vibration can be secured.

  In the aspect in which the amplification factor of the acceleration detection signal in each vibration mode is intentionally set to a different value, when the rotation speed of the dehydration tank is equal to or less than the first value, the first axial direction (dehydration tank rotation) If the vibration of the dehydration tank is detected based on the acceleration detection signal in the direction orthogonal to the axis), and the rotation speed of the dehydration tank exceeds the first value, the second axial direction (the rotation axis direction of the dehydration tank) It is preferable that the vibration of the dehydration tank is detected based on the acceleration detection signal at.

  According to this aspect, the detection mode for selectively detecting the lateral vibration is selected at the stage where the rotational speed of the dehydrating tank is small and the lateral vibration is dominant, and then the rotational speed is increased to some extent, and the longitudinal vibration is dominant. At this stage, switching to a detection mode for detecting longitudinal vibration is performed. By doing so, the vibration of the dehydration tank can be detected effectively.

  The vibration detection mechanism of the present invention is a mechanism for detecting the vibration of the dewatering tub of the washing machine, the first vibration in the direction orthogonal to the rotation axis direction of the dehydration tub, and the second vibration in the rotation axis direction of the dehydration tub. An acceleration sensor that detects vibration and an amplification circuit that amplifies the output of the acceleration sensor, and the amplification factor of the output of the acceleration sensor in response to the first vibration is the amplification of the output of the acceleration sensor in response to the second vibration It can also be grasped as a configuration characterized by being larger than the rate.

  Moreover, this invention can also be grasped | ascertained as a method of detecting the vibration of the dewatering tank of a washing machine. That is, according to the present invention, the first vibration in the direction orthogonal to the rotation axis direction of the dehydration tub of the washing machine and the second vibration in the rotation axis direction of the dehydration tub are detected by the acceleration sensor, and the initial rotation of the dehydration tub is detected. , The output of the acceleration sensor in response to the first vibration is amplified with the first amplification factor, and the output of the acceleration sensor in response to the second vibration is It can also be grasped as a vibration detection method characterized in that amplification is performed at an amplification factor of 2, and the first amplification factor is larger than the second amplification factor.

  ADVANTAGE OF THE INVENTION According to this invention, the technique which detects the abnormal vibration in the dehydration apparatus which shows the vibration mode which changes with rotation speed effectively is provided.

1. First embodiment (configuration of the embodiment)
Hereinafter, the example at the time of applying the vibration detection mechanism of this invention to the 1 tank type washing machine is demonstrated. FIG. 1 is a sectional view showing an example of a sectional structure of a washing machine. FIG. 1 shows a state in which the washing machine 101 includes legs 103 and is arranged on a suitable base 104. The washing machine shown in FIG. 1 has a function of performing washing and subsequent dehydration using the washing tub / dehydration tub 108.

  A washing machine 101 shown in FIG. 1 includes a washing tub / dehydration tub 108 in which an outer tub 105 and a laundry 114 are placed in an outer structure 102. The outer tub 105 has a structure suspended from the outer structure 102 in the outer structure 102 by a suspension member 106. A spring 107 is disposed between the suspension member 106 and the outer tub 105, and the outer tub 105 is elastically suspended in and supported by the outer structure 102.

  A motor 111 is attached to the outer tub 105, and a rotating shaft 112 of the motor 111 is supported by a bearing 113 so that rotational driving force can be transmitted to the washing tub / dehydrating tub 108 and the stirring blade 109. The motor 111 is a motor that performs an operation in which the rotational speed increases to the maximum rotational speed when energization is started.

  At the time of washing (for example, washing with a detergent) or rinsing, the driving force of the motor 111 is not transmitted to the washing tub / dehydration tub 108, but the driving force is transmitted to the stirring blade 109 and is put in the washing tub / dehydration tub 108. The laundry and the poured water are agitated.

  At the time of dehydration, the stirring blade 109 is fixed to the washing tub / dehydration tub 108, and the washing tub / dehydration tub 108 is driven by a motor 111 to rotate relative to the outer structure 102. The mechanism for switching the drive from the motor 111 is provided on the rotating shaft 112 although details are not shown.

  In addition, a flexible hose 116 is connected to the outer tank 105 via a drain valve 115, and an acceleration sensor 117 for detecting vibration of the outer tank 105 is attached.

  Although the acceleration sensor 117 is a single element as will be described later, it has a function capable of individually detecting acceleration in a three-dimensional direction. Here, a detection signal of acceleration (acceleration in the Z-axis direction) in the rotation axis direction of the washing tub / dehydration tub 108 (the axial direction of the rotation axis 112 of the motor 111, hereinafter referred to as the Z-axis) is orthogonal to the acceleration sensor 117. A detection signal of acceleration (acceleration in the X-axis direction) in the axial direction (horizontal direction, hereinafter referred to as X-axis) is obtained.

  Next, an example of a vibration detection mechanism that detects the vibration of the washing tub / dehydration tank 108 will be described. FIG. 2 is a block diagram illustrating an example of a control system of the washing machine 101. 2 includes an acceleration sensor 117, a first amplifying device 201, a second amplifying device 202, a changeover switch 203, an A / D converter 204, a control device 206, a rotation speed detecting device 207, and various operation switches 208. A motor control device 209, a motor 210, various valves 211, and a display device 212.

  The acceleration sensor 117 is a Z-axis output that is an acceleration detection signal in the rotation axis direction of the washing tub / dehydration tub 108 and an acceleration detection signal X in a direction orthogonal to the rotation axis direction of the washing tub / dehydration tub 108. Outputs shaft side output.

  The X-axis side output from the acceleration sensor 117 is amplified by the first amplifying device 201, and the Z-axis side output is amplified by the second amplifying device 202. Here, the amplification factor (gain) of the first amplification device 201 is set to be 10 times larger than the amplification factor (gain) of the second amplification device 202.

  One of the output of the first amplifying device 201 and the output of the second amplifying device 202 is selected by the changeover switch 203 and sampled at a predetermined sampling interval by the A / D converter 204. The output of the A / D converter 204 is input to the control device 206, and the control device 206 evaluates acceleration in each axial direction. Further, the control device 206 receives an output from the rotation speed detection device 207 that detects the rotation speed of the washing tub / dehydration tub 108 and a control signal from various operation switches 208 for performing various operations on the washing machine 101. The

  The control device 206 outputs a control signal to the motor control device 209 and controls the rotation of the motor 210. For example, the control circuit 206 can control the rotation speed of the motor 210. In addition, the control device 206 controls the opening / closing and opening / closing states of a valve (not shown) that controls water injection into the washing tub / dehydration tub 108 and the drain valve 115. In FIG. 2, a plurality of valves are collectively referred to as various valves 211 or the like. The display device 212 displays information related to the operation mode and operation details. As the display device 212, display using a lamp, display using an LCD screen, or the like is used.

  Next, an example of the acceleration sensor 117 will be described. FIG. 3 is a plan view and a cross-sectional view showing an example of the acceleration sensor. 3A is a plan view, and FIG. 3B is a cross-sectional view taken along line BB in FIG. 3A.

  The acceleration sensor 117 is a triaxial acceleration sensor capable of detecting triaxial acceleration orthogonal to the XYZ axis directions. The acceleration sensor 117 includes a casing 1, an acceleration detection unit 2, a circuit board 3, a cover 4 and a terminal 5. A recess 11 is formed in the casing 1. The acceleration detector 2 is provided with a diaphragm 21 made of a rectangular thin metal plate. On one surface of the diaphragm 21, a weight 22 is fixed at the center, and the weight 22 is stored in the recess 11. A thin film piezoelectric element 23 is fixed in close contact with the other surface of the diaphragm 21. Electrodes 24 and 26 are formed on the surface of the piezoelectric element 23. A wiring pattern is drawn out from the electrodes, and the wiring pattern is electrically connected to the extraction electrodes 25a to 25c. The diaphragm 21 may be a circular metal thin plate or the like in addition to a rectangular metal thin plate such as a rectangular shape or a square shape.

  The extraction electrodes 25 a to 25 c are connected to an amplifier circuit on the circuit board 3 by wire bonding (not shown) so that an output from the amplifier circuit on the circuit board 3 appears at the terminal 5. An IC chip 31 that constitutes an amplifier circuit is disposed on the circuit board 3.

  When the acceleration sensor 117 performs an acceleration motion, the diaphragm 21 is distorted by the inertia of the weight 22. This distortion acts on the piezoelectric element 23, and a voltage corresponding to the degree of distortion of the diaphragm 21 appears on the electrodes 25 a to 25 c, which is amplified by the amplifier circuit on the circuit board 3 and output from the terminal 5. In this configuration, since the direction of acceleration applied to the acceleration sensor 117 is reflected in the degree of distortion of the diaphragm 21, the acceleration in the three-dimensional direction can be detected individually.

  For example, in the X-axis direction and the Y-axis direction shown in FIG. 3, the pair of electrodes (for example, the electrode 24 a and the electrode 24 b) disposed to face the center of the diaphragm 21 are generated according to compression or tension. The piezoelectric element 23 is set so that the polarities of the charges are opposite to each other. In addition, in the substantially triangular four electrode portions 26, the piezoelectric elements 23 are set so that the polarities of the charges generated in response to compression or tension are all the same.

  According to this example, when the acceleration sensor 117 receives acceleration in the X-axis direction, the weight 22 is tilted in the X-axis direction, and a voltage appears at the extraction electrode 25a. This voltage is reversed in polarity when the direction of acceleration differs by 180 degrees. For example, when the acceleration sensor 117 receives acceleration in the Y-axis direction, the weight 22 is tilted in the Y-axis direction, and a voltage appears at the extraction electrode 25b. This voltage also reverses its polarity when the direction of acceleration differs by 180 degrees. For example, when the acceleration sensor 117 receives acceleration in the Z-axis direction, the weight 22 moves in the Z-axis direction, and a voltage appears at the extraction electrode 25c. This voltage also reverses its polarity when the direction of acceleration differs by 180 degrees. In this way, acceleration applied in the XYZ triaxial directions is output as an electrical signal.

  In the present embodiment, the acceleration sensor 117 functions as a biaxial acceleration sensor, and only needs to be able to detect the acceleration in the rotation axis direction of the washing tub / dehydration tub 108 and the acceleration in the direction orthogonal to the rotation axis. One is not used.

(Operation of the embodiment)
Next, an example of the operation procedure of the dehydrating operation of the washing machine shown in FIGS. 1 and 2 will be described. FIG. 4 is a flowchart showing an example of the operation procedure of the dehydrating operation of the washing machine 101. When the motor 111 is energized, starts rotating, and starts dehydration (step S400), the number of rotations of the motor 111 increases. At this time, the X-axis side output is first selected by the changeover switch 203 of FIG. 2 (step S401), and it is further determined whether the X-axis side output is equal to or lower than the first voltage (step S402). This voltage is detected by the control device 206.

  In step S402, it is determined whether or not lateral vibration of an unacceptable magnitude has occurred in the washing tub / dehydration tub 108. The value of the first voltage may be obtained based on a test result obtained by attaching an acceleration sensor to the actual machine of the washing machine, performing a test in which abnormal vibration actually occurs during the dehydrating operation.

  If the determination in step S402 is NO, it is determined that an unacceptable lateral vibration (vibration in the X-axis direction) has occurred, and therefore processing for stopping the rotation of the washing tub / dehydration tub 108 is performed. That is, the control device 206 sends a signal to the motor control device 209 to stop the motor 210 and stops the motor 210. At this time, a warning alarm may be notified using a warning sound generator (not shown).

  If the determination in step S402 is NO, the laundry to be dehydrated is in a state of being biased in the washing tub / dehydration tub 108, the weight balance is remarkably deteriorated, and further dehydration is difficult. It means that. Accordingly, the rotation of the washing tub / dehydration tub 108 is stopped as shown in step S403.

  If the determination in step S402 is YES, it is determined whether it is equal to or higher than the first rotational speed (step S404), and if the rotational speed of the washing tub / dehydration tank 108 is equal to or higher than the first rotational speed, step Proceed to S405, otherwise return to the previous stage of step S402.

  As the first number of rotations, for example, about 100 rotations (number of rotations / minute) is selected. This is because the vibration mode gradually switches from the vibration mode of the transverse vibration (vibration in the X-axis direction) to the vibration mode of the longitudinal vibration (vibration in the Z-axis direction). If step S404 is NO, it is still a vibration mode of transverse vibration, and there is a possibility that the rotation must be stopped due to intensification of vibration, so step S402 is executed again.

  On the other hand, if it is determined in step S404 that the rotation speed of the washing tub / dehydration tank 108 is equal to or higher than the first rotation speed, the vibration mode of the washing tub / dehydration tank 108 is becoming a vibration mode of longitudinal vibration. It means that there is. Therefore, when the determination in step S404 is YES, the process proceeds to step S405 to shift to a vibration detection mode in which longitudinal vibration is detected.

  In step S405, the Z-axis side output is selected by the switch 204 in FIG. 2, and it is determined whether the Z-axis side output is equal to or lower than the second voltage (step S406). The second voltage is set as a detected value of vibration at a level at which the vertical vibration generated in the washing tub / dehydration tub 108 should be subjected to some treatment (a level that can be tolerated but cannot be ignored).

  In step S406, if the Z-axis side output is equal to or lower than the second voltage, it is determined whether it is equal to or higher than the second rotation speed (step S407). Otherwise, the process proceeds to step S410.

  Here, the second rotational speed is selected from the vicinity of the rotational speed at which it can be determined that there is no problem even if the maximum rotational speed is reached as it is. For example, when the set maximum rotation speed is 1000 rotations per minute, a rotation speed of about 800 rotations per minute is selected as the second rotation speed.

  For example, when the maximum rotation speed is about 1000 rotations, if abnormal vibration does not occur in the vicinity of 800 rotations, the rotation continues as it is, and even if it reaches 1000 rotations, abnormal vibration will occur in the meantime. Absent. This is because a stable rotational state has already been reached in the state of 800 revolutions. From such technical background, the second rotational speed is selected.

  If the determination in step S407 is yes, the process proceeds to step S408, and the rotational speed is increased to a predetermined maximum rotational speed. Then, it is determined whether or not the elapsed time of the dehydration process at the maximum number of revolutions is a predetermined time (step S409). If the predetermined time has elapsed, the process proceeds to step S416, where the washing tank / dehydration tank 108 is set. A process for stopping the rotation is performed, and the dehydration is terminated (step S417). On the other hand, if the predetermined time has not elapsed, the process returns to the previous stage of step S406, and step S406 and subsequent steps are repeated again.

  Even if the determination in step S409 is NO, if dehydration at the maximum rotational speed has progressed without any problem, the determination in step S406 is YES, the determination in step S407 is also YES, and the processing in steps S406 to S409 is performed. The process is repeated until a predetermined time elapses.

  If any abnormal vibration occurs during dehydration at the maximum rotation speed, the determination in step S406 is NO, and the processing in step S410 and subsequent steps is executed.

  In step S410, it is determined whether the current rotation speed is a specific rotation speed, for example, about 400 rotations. If the rotation speed is lower than the specific rotation speed, the process proceeds to step S415, and the rotation of the washing tub / dehydration tub 108 is performed. To stop. If the current rotational speed is equal to or higher than the specific rotational speed, the process proceeds to step 411 and processing for reducing the rotational speed to the specific rotational speed is performed. Then, the reduced rotational speed is maintained for a predetermined time (step S412), and it is determined again whether the Z-axis side output is equal to or lower than the second voltage (step S413).

  If the Z-axis side output is not equal to or lower than the second voltage, step S415 is executed, and the washing tub / dehydration tub 108 is stopped. If the determination in step S413 is YES, it is determined whether the time (dehydration time) corresponding to the adjusted rotational speed has elapsed (step S414). If the predetermined time has elapsed, the process proceeds to step S416. Otherwise, return to the previous stage of step S412. The elapsed time determined in step S414 is set to a length of about 1.5 to 3 times the elapsed time determined in step S409.

  In this way, by lowering the rotation of the washing tub / dehydration tub 108 to a level where vibration can be allowed, dehydration can be automatically performed to the end without interrupting dehydration.

  Although not shown in FIG. 4, when the rotation of the washing tub / dehydration tub 108 is stopped in step S403, the following steps may be performed. That is, after step S403, water is injected and the washing tub / dehydration tub 108 is rotated a plurality of times in the forward and reverse directions. By doing so, the bias of the laundry is eliminated. Thereafter, the processing from step S401 is executed again. By doing so, dehydration can be automatically restarted.

  In the operation described above, the output on the X-axis side is selected in step S401 at the initial stage of rotation, and the output on the Z-axis side is selected instead of the output on the X-axis side when the rotation speed reaches a certain level. By doing so, the lateral vibration (vibration in the X-axis direction) in the initial rotation of the washing tub / dehydration tub 108 is performed with high sensitivity via the high gain amplifying device 201, the rotational speed increases to some extent, and longitudinal vibration is a problem. At this stage, the detection of the acceleration in the Z-axis direction via the low gain amplifying device 201 is performed in a detection mode that can cope with a stronger input.

  As described above, in this embodiment, the axis of acceleration to be detected is changed in accordance with the change in the vibration mode that changes depending on the number of rotations of the washing tub / dehydration tub, and the amplification factor is switched in accordance with the vibration mode. This increases the gain of the amplifying device for vibrations with small acceleration, thereby increasing the detection sensitivity, and weakens the gain of the amplifying device for vibrations with large acceleration, thereby detecting the device (for example, an A / D converter). Can be prevented from being saturated by strong input. In this way, optimal vibration detection according to the vibration mode can be realized while ensuring a wide dynamic range.

2. Other Embodiments The following examples can be given as other embodiments. FIG. 5 is a block diagram illustrating another example of the vibration detection mechanism of the washing machine. In the configuration shown in FIG. 5, the two-axis outputs of the acceleration sensor 117 are connected to DSPs (digital signal processors) 501 and 502 each having an A / D converter. In the DSPs 501 and 502, signal processing corresponding to each of the X-axis side output and the Z-axis side output is performed, and the output is switched by the changeover switch 203. Also in this case, effective vibration detection can be performed according to the difference in the direction of acceleration due to the difference in vibration mode and the difference in the intensity of acceleration.

  In addition, the following embodiments can be given. In the configuration shown in FIG. 2, amplifying devices having different amplification factors are arranged for the Z-axis side output and the X-axis side output, respectively. As a modification, the amplification factor may be switched by a single amplification device. In this case, when the X-axis side output is selected, the low amplification factor is selected, and when the Z-axis side output is selected, the high amplification factor is selected.

  The dehydrating tank to which the present invention can be applied is a so-called horizontal type in which the rotation axis is not in the vertical direction, or an oblique type (a structure in which the rotation axis is inclined at 45 degrees or the like with respect to the vertical direction). Also good.

  INDUSTRIAL APPLICABILITY The present invention can be used for a vibration detection technique in which vibration having anisotropy with different vibration modes in orthogonal axis directions is detected independently in each axis direction by an acceleration sensor. Especially this invention can be utilized for the vibration detection of the dehydration tank of a washing machine.

It is sectional drawing which shows an example of the cross-sectional structure of a washing machine. It is a block diagram which shows an example of the control system of a washing machine. It is the top view (A) and sectional drawing (B) which show an example of an acceleration sensor. It is a flowchart which shows an example of the operation | movement procedure of the spin-drying | dehydration operation of a washing machine. It is a block diagram which shows another example of the control system of a washing machine.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 101 ... Washing machine, 102 ... Outer structure, 103 ... Leg part, 104 ... Base, 105 ... Outer tub, 106 ... Hanging member, 107 ... Spring, 108 ... Washing tub and dehydration tub, 109 ... Stirring blade, 111 ... Motor , 112 ... rotating shaft, 113 ... bearing, 114 ... laundry, 115 ... drainage valve, 116 ... flexible hose, 117 ... acceleration sensor, 201 ... first amplifying device, 202 ... second amplifying device, 203 ... changeover switch 204 ... A / D converter, 206 ... control device, 207 ... rotation speed detection device, 208 ... various operation switches, 209 ... motor control circuit, 210 ... motor, 211 ... various valves, etc., 212 ... display device, 501 ... DSP , 502 ... DSP, 1 ... casing, 2 ... acceleration detection unit, 3 ... circuit board, 4 ... cover, 5 ... terminal, 11 ... recess, 21 ... diaphragm Beam, 22 ... weight, 23 ... piezoelectric element, 24 ... electrode, 25 a to 25 c ... take-out electrode, 26 ... electrode, 31 ... IC or the like.

Claims (6)

An acceleration sensor that detects acceleration in a first axial direction and acceleration in a second axial direction orthogonal to the first axis;
A vibration member that exhibits a first vibration mode in the first axial direction and a second vibration mode different from the first vibration mode in the second axial direction, and vibration is detected by the acceleration sensor When,
A first process is applied to the acceleration detection signal in the first axial direction from the acceleration sensor, and the first process is applied to the acceleration detection signal in the second axial direction from the acceleration sensor. A vibration detection mechanism comprising: a signal processing device that applies different second processing. The vibrating member is a dehydration tank of a washing machine,
The vibration detection mechanism according to claim 1, wherein the second axial direction substantially coincides with a rotational axis direction of the dewatering tank. The first and second processes are amplification processes for amplifying an acceleration detection signal;
The vibration detection mechanism according to claim 2, wherein the amplification factor in the first process is larger than the amplification factor in the second process. When the rotation speed of the dehydrating tank is equal to or less than a first value, vibration of the dehydrating tank is detected based on an acceleration detection signal in the first axial direction,
The vibration of the dehydration tank is detected based on an acceleration detection signal in the second axial direction when the rotation speed of the dehydration tank exceeds the first value. Vibration detection mechanism. A method for detecting vibrations in a washing machine dehydration tank,
A first vibration in a direction perpendicular to the rotation axis direction of the dehydration tank and a second vibration in the rotation axis direction of the dehydration tank are detected by an acceleration sensor;
In the initial stage of rotation of the dehydration tank, the output of the acceleration sensor in response to the first vibration is amplified by a first amplification factor,
In the stage where the number of rotations of the dehydration tank is increased, the output of the acceleration sensor in response to the second vibration is amplified by a second amplification factor,
The vibration detection method according to claim 1, wherein the first amplification factor is larger than the second amplification factor. When the rotation speed of the dehydrating tank is equal to or lower than the first value, the first vibration is detected,
The vibration detection method according to claim 5, wherein the second vibration is detected when the number of rotations of the dehydration tank exceeds the first value.

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