washing machine

Abstract

The washing machine disclosed herein includes: a housing; a water tank, vibration-dampingly supported inside the housing; an inner tub, rotatably disposed inside the water tank; and a rotating shaft fixed to the bottom of the inner tub. Furthermore, the washing machine includes: a motor, driving the inner tub to rotate via the rotating shaft; and a water level detection unit for detecting the water level accumulated inside the water tank. At least the water tank and the inner tub constitute a water tank unit. The water level detection unit includes: a flexible hose installed in the water tank; and a pressure detection unit for detecting pressure changes inside the flexible hose. The pressure detection unit is installed in the water tank unit.

Description

[Technical Field]

[0001] Field of Invention

[0002] This disclosure relates to a washing machine. [Previous Technology]

[0003] Background of the Invention

[0004] For example, Patent Document 1 discloses a washing machine in which a water level detection mechanism is installed in the casing of the washing machine.

[0005] Patent Document 1 describes a washing machine comprising a housing, a water tank internally supported by vibration damping, and a water level detection unit for detecting the water level accumulated inside the water tank. The water level detection unit includes: a diaphragm that operates under pressure, the pressure being the pressure of the water level in an air trap connected to the outer tank, and a transmission circuit whose transmission frequency changes due to the operation of the diaphragm. The water level detection unit is mounted on the housing. [Prior Art Document]

[0006] [Patent Document] [Patent Document 1] Japanese Patent Application Publication No. 2014-68736 [Summary of the Invention]

[0007] Summary of the Invention

[0008] This disclosure provides a washing machine that can suppress problems caused by vibration in water level detection.

[0009] The washing machine disclosed herein includes: a housing; a water tank, vibration-dampingly supported inside the housing; an inner tub, rotatably disposed inside the water tank; and a rotating shaft fixed to the bottom of the inner tub. Furthermore, the washing machine disclosed herein includes: a motor, driving the inner tub to rotate via the rotating shaft; and a water level detection unit for detecting the water level accumulated inside the water tank. At least the water tank and the inner tub constitute a water tank unit. The water level detection unit includes: a flexible hose installed in the water tank; and a pressure detection unit for detecting pressure changes inside the flexible hose. The pressure detection unit is installed in the water tank unit.

[0010] The washing machine disclosed herein can suppress problems caused by vibration during water level detection.

Implementation Method

[0016] [Type of invention used to implement the invention]

[0017] Hereinafter, the implementation will be described in detail with reference to the drawings. However, there will be instances where detailed descriptions are omitted when necessary. For example, detailed descriptions of already well-known matters may be omitted, or descriptions of substantially the same components may be repeated. This is to avoid the following description becoming excessively lengthy and to make it easier for those skilled in the art to understand.

[0018] Furthermore, the accompanying drawings and the following description are provided to enable those skilled in the art to fully understand this disclosure, and are not intended to limit the subject matter described in the patent application. (Embodiment 1)

[0019] Hereinafter, Embodiment 1 of this disclosure will be described using Figures 1 to 5. Furthermore, in the following description, the front side shown in Figures 1 to 3 will be referred to as the front, and the rear side as the rear. [1. Structure] [1-1. Basic Structure of a Washing Machine]

[0020] FIG1 is a cross-sectional view showing the configuration of the washing machine 100 in Embodiment 1. FIG2 and FIG3 are perspective views showing the configuration of the sink unit 109 of the washing machine 100. FIG2 is the front side of the sink unit 109 and FIG3 is the rear side of the sink unit 109.

[0021] The washing machine 100 in this embodiment is configured as a drum-type washing machine. As shown in FIG1, the washing machine 100 includes a housing 110, a water tank 102, a rotating drum 101 as an example of the inner tub disclosed herein, a rotating shaft 105, a drum drive motor 108 as an example of the motor disclosed herein, and a water level detection unit 130 (see FIG2).

[0022] The water tank 102 is disposed inside the housing 110 of the washing machine 100. The water tank 102 is formed into a bottomed cylindrical shape with an opening at the front, and is configured to store water inside. A water supply path (not shown) for supplying tap water and a drain path 112 for draining water from the inside of the water tank 102 are connected to the water tank 102. The water tank 102 is supplied with water through the water supply path when the water supply valve (not shown) is open, and drains water through the drain path 112 when the drain valve (not shown) is open.

[0023] The rotating drum 101 is formed as a bottomed cylindrical shape with an opening at the front, and is disposed inside the water tank 102 in a manner opposite to the opening of the water tank 102. The rotating drum 101 is configured inside the water tank 102 and is driven to rotate by the drum drive motor 108 described later.

[0024] A bearing housing 103 with a bearing 104 supporting a rotating shaft 105 is provided at the bottom of the back side of the water tank 102. The rotating shaft 105 is located at the rotation center at the bottom of the back side of the rotating drum 101, and its axial direction is inclined downward from the front side to the back side. As shown in FIG3, a roller pulley 106 is provided at the bottom of the back side of the water tank 102 with the rotating shaft 105, and a roller drive motor 108 is provided at the lower part of the water tank 102. The roller drive motor 108 is connected to the rotating shaft 105 through a transmission belt 107 and a roller pulley 106, and drives the rotating drum 101 to rotate in the forward and reverse directions through the rotating shaft 105. The water tank unit 109 is constituted by the above-mentioned rotating drum 101, water tank 102, roller drive motor 108, bearing housing 103, transmission belt 107, and roller pulley 106. The water tank unit 109 is a vibrating body that vibrates as a whole, accompanying the vibration of the water tank 102.

[0025] The water tank unit 109 is elastically supported within the housing 110 by a plurality of suspension devices 111. The lower end of the suspension device 111 is connected to the upper part of the water tank 102, and the upper end of the suspension device 111 is connected to the upper part of the housing 110. That is, the water tank 102 is vibration-damped and supported by the suspension devices 111.

[0026] As shown in Figure 2, a water tank cover 115 is installed on the front surface of the water tank 102. A water level detection unit 130 is installed on the upper part of the water tank cover 115.

[0027] The water level detection unit 130 is used to detect the water level inside the water tank 102, and includes a water level and vibration detection device 113 (described later) and a flexible hose 114 installed in the water tank 102. One end of the flexible hose 114 is connected to the lower part of the back side of the water tank 102 (see Figure 3), and is configured such that water in the water tank 102 can flow into the flexible hose 114. The other end of the flexible hose 114 is connected to the water level detection unit 123 at the left side of the water tank cover 115. [1-1-2. Configuration of the water level and vibration detection device]

[0028] Figure 4 is a schematic diagram showing the configuration of the water level and vibration detection device 113 of the washing machine 100. As shown in Figure 4, the water level and vibration detection device 113 includes a printed circuit board 125, a water level detection unit 123, a vibration detection unit 124, and a housing 122. Furthermore, the water level detection unit 123 is an example equivalent to the pressure detection unit disclosed herein.

[0029] The water level detection unit 123 is a sensor used to detect pressure changes inside the hose 114, and it is constructed using a silicon piezoresistive pressure sensor, i.e., a MEMS (Micro Electro Mechanical Systems) sensor. Furthermore, as shown in FIG2, the water level and vibration detection device 113, which includes the water level detection unit 123, is installed on the upper part of the water tank cover 115, that is, the water level detection unit 123 is installed on the water tank unit 109.

[0030] The vibration detection unit 124 is a sensor used to detect the vibration of the water tank unit 109, and is composed of a 3-axis accelerometer, i.e., a MEMS sensor. The printed circuit board 125 is connected to the control unit 127 via leads 126 for power control or transmission and reception of communication signals. The leads 126 are, for example, power lines, GND lines, pressure detection sequence communication lines, vibration detection sequence communication lines, etc.

[0031] The control unit 127 controls the program including the cleaning cycle, rinsing cycle, or dehydration cycle described later, and executes the origin correction processing described later. Furthermore, the control unit 127 includes a computer system with a processor and memory. The computer system performs the functions of the control unit 127 by executing a program stored in memory through the processor. The program executed by the processor is pre-recorded in the computer system's memory; however, it may also be provided through a non-temporary recording medium such as a memory card, or through electronic communication lines such as the Internet. Moreover, the control unit 127 is not limited to implementing the above functions through hardware and software cooperation; any dedicated hardware circuitry that implements the above functions is acceptable.

[0032] The water level detection unit 123 and the vibration detection unit 124 are mounted on the printed circuit board 125. The printed circuit board 125 is housed within the housing 122 with the water level detection unit 123 mounted facing downwards.

[0033] The hose 114 connected to the water level detection unit 123 is fixed to the housing 122 by a fixing mechanism 121. The fixing mechanism 121 is constructed by, for example, a strap. The hose 114 extends outward from the housing 122 through an opening (not shown) provided on the lower surface of the housing 122.

[0034] In this embodiment, by mounting the water level detection unit 123 and the vibration detection unit 124 onto the printed circuit board 125, compared to the case where the water level detection unit 123 and the vibration detection unit 124 are set up independently, the number of leads can be reduced. [1-2. Operation]

[0035] Regarding the washing machine 100 configured as described above, its operation and function will be explained below. [1-2-1. Washing Operation]

[0036] The following describes the washing operation. The washing operation is an example of a process that includes the washing cycle, rinsing cycle, and spin-drying cycle.

[0037] When the washing operation begins, the washing cycle is executed first. During the washing cycle, after the water supply to the water tank 102 is executed, the rotating drum 101 performs a predetermined time of repeated forward, stop, reverse, and stop agitation. During the agitation, the clothes contained in the rotating drum 101 are lifted in the direction of rotation by several protruding plates for agitation and fall from the height they are lifted. In this way, a tumbling effect is applied to the clothes contained in the rotating drum 101. Afterward, the spin-drying operation is executed. During the spin-drying operation, the drain valve is opened, and the water in the water tank 102 is drained to the outside through the drain path 112. With the drain valve open, the rotating drum 101 rotates at high speed for a predetermined time. In this way, the water contained in the clothes is dehydrated by centrifugal force and drained through the drain path 112. During the spin-drying operation, the water tank unit 109 vibrates significantly.

[0038] After that, the rinsing cycle is performed. In the rinsing cycle, similar to the washing cycle, after the water supply operation is performed, the agitation operation is performed for a predetermined time. Hereby, the detergent ingredients contained in the clothes are diluted, and the clothes are rinsed.

[0039] Afterwards, the dehydration cycle is executed. During the dehydration cycle, the final dehydration action is performed. After the final dehydration action is performed, the origin correction process described later is performed. After the final dehydration action is completed, the washing operation ends. [1-2-2. Operation of the water level detection unit]

[0040] When water above a predetermined level is accumulated in the water tank 102, the water in the water tank 102 flows into the hose 114, and the internal pressure of the hose 114 rises according to the amount of water flowing in. The water level detection unit 123 detects the rise in internal pressure of the hose 114 and outputs an electrical signal corresponding to the amount of pressure rise. The control unit 127 receives the absolute value of the electrical signal from the water level detection unit 123 via the lead wire 126, and calculates the water level based on the absolute value and a reference value. The control unit 127 receives the electrical signal via the lead wire 126 and calculates the water level of the water tank 102.

[0041] In this embodiment, the water level detection unit 123 is constructed using a MEMS sensor. Conventionally, water level detection mechanisms are configured to detect the expansion and contraction of a spacer using an analog oscillating circuit. The expansion and contraction of the spacer is susceptible to interference from vibration or external noise, which can easily lead to errors in the detection results. Therefore, conventional water level detection mechanisms require mounting on a housing. In this embodiment, the washing machine 100 uses a MEMS sensor to construct the water level detection unit 123, which can be mounted on the vibrating sink unit 109. Because the water level detection unit 123 is mounted on the vibrating body of the sink unit 109, and both ends of the hose 114 are mounted on the sink unit 109, the washing machine 100 can prevent the hose 114 from detaching from the water level detection unit 123 due to vibration of the sink unit 109. Since the hose 114 is designed to be difficult to detach from the water level detection unit 123, the washing machine 100 can use inexpensive parts to construct the fixing mechanism 121 for securing the hose 114. Furthermore, since the hose 114 is less likely to vibrate relative to the sink unit 109, the accuracy of water level detection in the water level detection unit 123 is improved.

[0042] In this embodiment, the water level and vibration detection device 113 includes a water level detection unit 123 and a vibration detection unit 124. Assuming that the vibration detection mechanism is independently installed at a different location from the water level detection mechanism, an additional power supply line and a GND line are required to connect the vibration detection mechanism and the control mechanism. Furthermore, a mechanism is needed to fix the additional power supply line and GND line. By mounting the water level detection unit 123 and the vibration detection unit 124 on the same printed circuit board 125, the washing machine 100 can reduce the number of power supply lines and GND lines. [1-2-2. Origin Correction Processing of the Water Level Detection Unit]

[0043] Even if the absolute value of the electrical signal changes over time, the amount of displacement from the reference value remains approximately constant. Therefore, by obtaining the absolute value of the electrical signal under predetermined conditions and calculating the reference value based on the obtained absolute value of the electrical signal, the deviation of the absolute value of the reference value caused by the change over time can be corrected. In this embodiment, when water does not flow into the hose 114, that is, when the pressure caused by the flowing water is not applied to the water level detection unit 123, the control unit 127 performs origin correction processing for the reference value based on the electrical signal output from the water level detection unit 123.

[0044] Hereinafter, Figure 5 will be used to explain the origin correction process. Figure 5 is a flowchart showing the origin correction process of the washing machine 100. Furthermore, although not specifically mentioned, the washing machine 100 is equipped with a temperature sensor (not shown).

[0045] When the final dehydration operation ends, that is, when the drum drive motor 108 has stopped, the control unit 127 starts the origin correction process (step S100).

[0046] During this washing operation, the control unit 127 determines whether the washing cycle, rinsing cycle, and spin-drying cycle have been executed (step S101). If it is determined that not all cycles have been executed (step S101, No), the control unit 127 ends the origin correction process (step S107).

[0047] Upon determining that all cycles have been executed (step S101, Yes), the control unit 127 determines whether the temperature inside the washing machine 100 obtained from the temperature sensor is within the set temperature range of the pressure sensor constituting the water level detection unit 123 (step S102). The set temperature only needs to be a value that does not cause problems with the pressure sensor. If it is not within the set temperature range, the absolute value of the electrical signal output by the pressure sensor (water level detection unit 123) may be unreliable. If it is determined that it is not within the set temperature range (step S102, No), the control unit 127 ends the origin correction process (step S107).

[0048] If the temperature is within the set temperature range of the pressure sensor (step S102, yes), the control unit 127 obtains the origin correction value from the water level detection unit 123 (step S103). The origin correction value is the absolute value of the electrical signal (the electrical signal corresponding to the increase in internal pressure of the hose 114) under predetermined conditions.

[0049] The control unit 127 determines whether the origin correction value is within the set range (step S104). The set range is the range that takes into account the accuracy error range of the pressure sensor, i.e., the MEMS sensor. If the origin correction value is not within the set range (step S104, no), the control unit 127 ends the origin correction process (step S107).

[0050] When the origin correction value is within the set range (step S104, Yes), the control unit 127 calculates a new reference value based on the origin correction value (step S105). The reference value may also be a moving average obtained, for example, using a plurality of origin correction values. The control unit 127 stores the calculated reference value (step S106). After that, the control unit 127 ends the origin correction process (step S107).

[0051] Thus, in this embodiment, the origin correction processing begins after the final spin-drying operation is completed, provided that a sequence of operations including a washing cycle, a rinsing cycle, and a spin-drying cycle is executed. By limiting the origin correction processing to a sequence of operations including a washing cycle, a rinsing cycle, and a spin-drying cycle, the origin correction processing can be prevented from starting inside the detergent suds or water residue in the water tank 102. By configuring the origin correction processing to start after the final spin-drying operation, the washing machine 100 can begin the origin correction processing when the water tank 102 is not vibrating and the water in the water tank 102 is in its most drained state. [1-3. Effects, etc.]

[0052] As described above, the washing machine 100 in this embodiment includes a housing 110, a water tank 102 supported inside the housing 110 for vibration damping, a rotating drum 101 rotatably disposed inside the water tank 102, and a rotating shaft 105 fixed to the bottom of the rotating drum 101. Furthermore, the washing machine 100 includes a drum drive motor 108 that drives the rotating drum 101 to rotate via the rotating shaft 105, and a water level detection unit 130 for detecting the water level accumulated inside the water tank 102. At least the water tank 102 and the rotating drum 101 constitute a water tank unit 109. The water level detection unit 130 includes a flexible hose 114 installed in the water tank 102 and a water level detection section 123 for detecting pressure changes inside the flexible hose 114. The water level detection section 123 is installed in the water tank unit 109.

[0053] Therefore, since the water level detection unit 123 and the hose 114 are both disposed in the sink unit 109, the washing machine 100 can be configured in the vibration system of the sink unit 109 in the same way as the water level detection unit 123 and the hose 114.

[0054] Therefore, since the relative vibration of the hose 114 to the water level detection unit 123 can be suppressed, the accuracy of water level detection by the water level detection unit 123 can be improved. That is, the washing machine 100 can suppress problems caused by vibration in water level detection. Furthermore, since the relative vibration of the hose 114 to the water level detection unit 123 can be suppressed, the durability of the hose 114 can be improved. Also, the washing machine 100 can use an inexpensive fixing mechanism such as a cable tie as the fixing mechanism 121 for the hose 114.

[0055] As in this embodiment, the water level detection unit 130 may also include a vibration detection unit 124 for detecting the vibration of the water tank unit 109.

[0056] Thus, the washing machine 100 can have the function of detecting both the water level and vibration of the sink unit 109.

[0057] Therefore, since the washing machine 100 can gather the leads connecting the control unit 127 and the water level and vibration detection device 113, the number of leads or fixing mechanisms for fixing the leads can be reduced.

[0058] As in this embodiment, the water level detection unit 130 may also include a printed circuit board 125 on which the water level detection unit 123 and the vibration detection unit 124 are mounted.

[0059] Thus, since the water level detection unit 123 and the vibration detection unit 124 are mounted on the same printed circuit board 125, they can be miniaturized.

[0060] Therefore, since the washing machine 100 can make the lead wire connecting the control unit 127 and the water level and vibration detection device 113 into one, the number of lead wires or fixing mechanisms for fixing the lead wires can be reduced.

[0061] As in this embodiment, the water level detection unit 123 may also be composed of a MEMS sensor.

[0062] Therefore, since the water level detection unit 123 can be packaged into a MEMS sensor, it can be mounted on the same printed circuit board 125 as the vibration detection unit 124. Furthermore, since the washing machine 100 uses a MEMS sensor to construct the water level detection unit 123, the water level detection unit 123 can be disposed on the sink unit 109.

[0063] As in this embodiment, the washing machine 100 may also include a control unit 127 for controlling a program that includes a washing cycle, a rinsing cycle, or a spin-drying cycle. When the program includes all cycles of the washing cycle, rinsing cycle, and spin-drying cycle, the control unit 127 may also perform the following processing after the final spin-drying action in the spin-drying cycle ends. That is, the control unit 127 may also perform processing to set a reference value for calculating the water level based on the value of the pressure change inside the hose 114 detected by the display water level detection unit 123.

[0064] Therefore, since the washing machine 100 performs the above-mentioned processing (origin correction processing) when water has not flowed into the hose 114, that is, when the pressure caused by the water that has flowed into the hose 114 is not applied to the water level detection unit 123, a more accurate reference value can be set. (Other embodiments)

[0065] As described above, Embodiment 1 has been explained as an example of the technology in this disclosure. However, the technology in this disclosure is not limited to this and can also be applied to embodiments that have been modified, replaced, added, or omitted. Furthermore, new embodiments can be created by combining the constituent elements described in Embodiment 1 above.

[0066] In Embodiment 1, a drum-type washing machine has been described as an example of the washing machine disclosed herein. The washing machine disclosed herein is not limited to a drum-type washing machine, as any machine in which vibration occurs along with the rotation of the inner tub is acceptable. For example, the washing machine disclosed herein could also be a longitudinal washing machine.

[0067] In Embodiment 1, in the case of a complete cycle including a washing cycle, a rinsing cycle, and a spin-drying cycle, after the final spin-drying action in the spin-drying cycle ends, the origin correction process shown in Figure 5 is explained based on the pressure change value inside the hose detected by the display pressure detection unit. This is an example of the process (origin correction process) disclosed herein used to set a reference value for calculating the water level. The origin correction process disclosed herein can be performed as long as the water tank is not vibrating and there is no residual water in the water tank. The origin correction process disclosed herein can also be performed, for example, before or after the washing operation begins. That is, the origin correction process disclosed herein can also be performed after the final spin-drying action in the spin-drying cycle ends and before the next water supply action begins.

[0068] In Embodiment 1, a washing operation is described as an example of the procedure disclosed herein, which includes a washing cycle, a rinsing cycle, and a spin-drying cycle. The procedure disclosed herein, which includes a washing cycle, a rinsing cycle, and a spin-drying cycle, is not limited to a washing operation and may include other cycles. For example, when the washing machine disclosed herein is a front-loading washer-dryer with a drying function, it may also perform a washing-drying operation that includes a drying cycle, as an example of the procedure disclosed herein, which includes a washing cycle, a rinsing cycle, and a spin-drying cycle. In this case, the drying cycle may be performed after the spin-drying cycle. After the drying cycle is completed, the washing-drying operation ends. Afterwards, origin correction processing may also be performed.

[0069] In Embodiment 1, a configuration was described in which the washing operation ends after the final spin-drying action. Although not described in Embodiment 1, the washing machine 100 may also perform an action different from the spin-drying action after the final spin-drying action. For example, following the final spin-drying action, an action could be performed to loosen the clothes attached to the inner circumferential surface of the rotating drum 101, and then the washing operation could end. Then, a home correction process could be performed thereafter. [Industrial Application Possibilities]

[0070] This disclosure is applicable to washing machines. Specifically, for example, this disclosure is applicable to front-loading washing machines, vertical washing machines, etc. [Simplified Explanation of the Diagram]

[0011] Figure 1 is a cross-sectional view showing the configuration of the washing machine in Embodiment 1.

[0012] Figure 2 is a perspective view showing the front side configuration of the sink unit of the washing machine in Embodiment 1.

[0013] Figure 3 is a perspective view showing the configuration of the rear side of the water tank unit of the washing machine in Embodiment 1.

[0014] Figure 4 is a schematic diagram showing the configuration of the water level and vibration detection device of the washing machine in Embodiment 1.

[0015] Figure 5 is a flowchart showing the origin correction process of the washing machine in Embodiment 1.

Claims

1. A washing machine comprising: a housing; a water tank, vibration-dampingly supported inside the housing; an inner tub, rotatably disposed inside the water tank; a rotating shaft fixed to the bottom of the inner tub; a motor driving the inner tub to rotate via the rotating shaft; and a water level detection unit for detecting the water level of water accumulated inside the water tank, wherein at least the water tank and the inner tub constitute a water tank unit, and the water level detection unit comprises: a flexible hose installed in the water tank; and a pressure detection unit for detecting pressure changes inside the flexible hose, wherein the pressure detection unit is composed of a MEMS (Micro Electro Mechanical Systems) sensor and is installed in the water tank.

2. The washing machine of claim 1, wherein the aforementioned water level detection unit includes a vibration detection unit for detecting vibration of the aforementioned water tank unit.

3. The washing machine of claim 2, wherein the aforementioned water level detection unit includes a substrate on which the aforementioned pressure detection unit and the aforementioned vibration detection unit are assembled.

4. The washing machine of claim 1, which includes a control unit for controlling a program including a washing cycle, a rinsing cycle, and a spin-drying cycle, wherein when the program includes all the cycles of the washing cycle, the rinsing cycle, and the spin-drying cycle, after the final spin-drying action in the spin-drying cycle is completed, the control unit performs a process of setting a reference value for calculating the water level based on the value of the pressure change inside the hose detected by the pressure detection unit.

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