JP2007252429A - Drawer type dishwasher - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a drawer type dishwasher for preventing the risk that an operator gets injured by drawn operation of a dish washing tub automatically pulled in by a drive motor, controlling the drawn operation of the washing tub so as to prevent the risk of damaging dishes and simplifying the control means. <P>SOLUTION: The washing tub of the dishwasher is drawn in by the drive motor 19. A drive current meter 30 detects the drive current of the drive motor 19, a measured value from the drive current meter 30 is transmitted to a differentiation circuit 31 and a comparator circuit 33, a differential value is computed in the differentiation circuit 31, and the measured value is sent to a current stabilization determination means 32. The current stabilization determination means 32 determines a stable torque range when the differential value is equal to or lower than a reference value x held in a reference holding means 32a, and holds the current value as a stable current value. The stable current value is compared with the current measured value thereafter in the comparator circuit 33, and when the difference is equal to or larger than the reference value y, drive current abnormality is determined, and the drive motor 19 is stopped by a driving circuit 34. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention is a safety system for a pull-out type dishwasher, in particular, a safety system for a pull-out operation of a washing tub automatically performed by a drive motor. In addition, it is possible to prevent a worker from being injured with a hand or the like.

In the drawer type dishwasher incorporated in the sink of the system kitchen, the washing tank supported by the slide rails 16 and 17 is generally taken in and out manually. Is automatically performed (Japanese Patent Laid-Open No. 2002-345712).
This is as shown in FIG. 5, and the cleaning tank is opened at the top, and the tableware 3 is taken in and out of the tableware basket 4 from this opening. The inner lid 15k is automatically opened and closed in conjunction with the drawing-out of the washing tank 15, and when the inner lid 15k is closed, the gap between the upper end of the washing tank 15 and the inner lid 15k is sealed with the packing 15p.

A rack gear 18 is fixed to the lower part of the washing tank 15 in the front-rear direction, a drive motor 19 with a speed reducer is fixed to the dishwasher main body 14, and a pinion 19 a of the drive motor 19 is engaged with the rack gear 18. The drive circuit 34 in the load drive circuit 53 is controlled through the control means 52 by turning on / off an appropriate pull-in operation switch of the operation unit 51 provided on the front door 23, and the drive motor 19 is driven by the drive circuit 34. Then, the cleaning tank 15 is pulled and pulled out (FIG. 6).
When the pull-in switch is turned on, the washing tank starts and moves while being accelerated to a predetermined speed (torque fluctuation range), and then moves at a slow speed (for example, about 30 mm / sec) controlled at a constant speed. (Torque stabilization range)
However, in the drawer type dishwasher in which the washing tank 15 is driven by the drive motor 19, the washing tank 15 is automatically drawn when the operation switch is turned on. During the pull-in operation, there is a possibility that the operator suddenly rushes into the cleaning tank 15 for adding tableware and the like, and there is a danger that the operator may be caught and injured if the hand is pushed in. . In the case of this dishwasher, if the tableware 3 placed in the tableware basket 4 protrudes above the limit height by the inner frame at the tip of the dishwasher body, the tableware 3 collides with the inner frame at the tip of the dishwasher body. For example, there is a risk of damaging the tableware 3 or the like.

As mentioned above, although the danger during the drawing-in operation of the washing tub has been described, there is no risk that the tableware 3 collides with the dishwasher body during the pulling-out operation and the tableware 3 and the like are damaged.
It is desired that the above danger can be avoided by means as simple as possible.

In addition, the code | symbol 8 in the prior art of FIG. 7 is a washing nozzle, 9 is a water supply valve, 10 is a water supply hose. Reference numeral 23 denotes a front door, and 24 denotes a handle.
JP 2002-345712 A

  An object of the present invention is to prevent the risk of injury to the operator by the pull-out operation of the dishwashing tank that is automatically pulled in and pulled out by the drive motor, and to prevent the risk of the tableware being damaged by the pull-out operation. It is to control the drawing-in operation of the cleaning tank so that the control means can be simplified.

Means for solving the above-mentioned problems are constituted by the following (a), (b) and (c) on the premise of a drawer type dishwasher in which a washing tank is operated by a drive motor.
(A) having a drive torque detection means for the drive motor;
(B) having drive torque stability detection means;
(C) Having torque comparison means.

When the pull-in operation switch is turned on, the drive motor 19 is started and the pull-in operation is started. During this pull-in operation, the drive torque is detected by the drive torque detection means. Specifically, the drive torque detecting means is an ammeter for measuring the drive current of the drive motor, and a torque gauge is interposed between the drive shaft of the drive motor 19 and the pinion 19a (see FIG. 5). A means for electrically measuring the driving torque with a torque gauge may be employed.
The drive torque detected by the drive torque detection means is evaluated by the drive torque stability detection means and it is confirmed that the drive torque is almost stable, and the stable value at that time, that is, the stable torque value is held. Note that when the drive torque is stabilized, the stable torque value depends on the weight of the tableware in the cleaning tank, the sliding resistance of a sliding portion (for example, a rail) of the cleaning tank, and the like.
The torque comparison means compares the torque stability value and the subsequent torque measurement value during the period from when the torque stability and the stable torque value (current value) at that time are confirmed until the drive stops due to the completion of pull-in (torque stability range). When the difference is greater than or equal to the reference value, it is determined that the drive torque is abnormal. In this way, when a drive torque abnormality is confirmed, the drive motor is stopped.

  If the tableware collides with the inner frame of the tip of the dishwasher during the pull-in operation, or if the operator puts his hand into the washing tub and touches the tableware or tableware basket inside, this increases the pull-in resistance of the washing tub. Since the torque is increased, it is possible to determine a drive torque abnormality. When the drive torque abnormality is determined and confirmed, the pull-in operation is stopped by this.

 The drive torque detection means is a drive current meter for the drive motor, the drive torque stability detection means is a current stability detection means, and the torque comparison means is a drive current value (stable current) when the drive torque is determined to be stable. Is a calculation circuit that compares and evaluates the current value with the current value in the subsequent torque stabilization range, but the drive torque can also be measured electrically with a torque gauge. What is necessary is just to make it evaluate by a detection means.

  Also, instead of judging the torque abnormality using the current value (stable current value) when it is judged that the torque is stable as a reference value, the current change rate is used as the reference value, and the measured current value in the torque stable region is differentiated and the derivative is obtained. The torque abnormality can also be determined by comparing the value with the reference value. In this case, the judgment criteria for torque stability and torque abnormality can be set to the same rate of current change, and in this way, torque abnormality can be judged as compared with the case where the current value is used as a reference value. Can be simplified.

  The operation when the pull-in operation switch is turned on and the pull-in operation is performed has been described above, but the operation when the pull-out operation switch is turned on and the pull-out operation is performed is the same.

Note that torque stability is determined based on the detected fluctuation range of the drive current value. When torque abnormality is also determined, torque stability is determined based on the change rate width (differential value width) of the drive current value. 1 also shows a trend as shown in FIG. 1 in the torque fluctuation region (at the start of the pull-in operation), and therefore, after the maximum torque value is confirmed, the reference such as the drive current fluctuation range or the differential value is below a predetermined value. Therefore, it is necessary to configure the torque stability determination means so that the torque stability is regarded as stable.
And “retraction” in the description of the claims means “retraction (or withdrawal)”.

If the tableware placed in the tableware basket protrudes above the limit height and this collides with the dishwasher body (the inner frame at the tip, etc.) during the pull-in operation (or during the pull-out operation), the resistance to the washing tank drive motor will be reduced. The drive current increases instantaneously and the drive current increases instantaneously. This increase in current is detected at the time of tableware collision, and the drive motor is stopped instantaneously, the impact on the tableware is reduced, and the breakage is prevented.
In addition, when the operator rushes into the cleaning tank and puts his hand into the cleaning tank and touches the tableware in the cleaning tank, the resistance to the drive motor increases momentarily and the drive current increases instantaneously. . When the operator's hand touches the tableware or the like, this increase in current is detected instantaneously, and the pull-in drive by the drive motor is quickly stopped, so that the operator is prevented from being injured.

  As described above, it is possible to prevent the operator from being injured or damaged due to the automatic pull-in or pull-out of the washing tank by detecting the fluctuation in the driving torque of the driving motor. Since it is configured by an extremely simple electric circuit such as differentiation and comparison, the configuration is very simple and its operation is stable.

Speaking of an example of a conventional dishwasher as shown in FIG. 5, the weight of the washing tub body to be taken in and out (including the weight of the washing water) is about 10 kg, and the average dish weight of a family of five (at dinner) is The total weight of the washing tank drawn by the drive motor 19 is about 20 kg. When this is pulled in while being guided by the guide rail, the pulling speed reaches 30 mm / sec after about 2.5 seconds (after about 75 mm stroke in this example), and then the pulling is stably performed at this speed (stable Area).
At the beginning of drawing-in, inertial resistance and sliding resistance are applied, and the maximum value of the resistance is about 4 kg. After 75 mm stroke, the resistance becomes about 2 kg and becomes stable. This is a resistance of only sliding resistance, and the driving torque value at this time is a stable torque value.
An example of the resistance trend with respect to the drive motor during the pull-in operation is shown in FIG. 1 as a change in the drive current value of the drive motor 19.

The detection system for detecting an increase in pulling resistance in this embodiment is as shown in the block diagram of FIG. In this detection system, the drive ammeter 30 for detecting the drive current of the drive motor 19 is provided in the drive circuit 34, the differentiation circuit 31, the current stability determination means 32, and the comparison circuit 33 are provided in the control means 52. Thus, the drive circuit 34 in the load drive circuit 53 is stopped.
The measured value from the drive ammeter 30 is transmitted to the differentiating circuit 31 and the comparing circuit 33, differentiated by the differentiating circuit 31 to calculate the rate of change, and the measured current value is transmitted to the current stability determining means 32. The current stability determining means 32 determines that the stable torque range has been reached when the differential value is less than or equal to the reference value x held in the reference holding means 32a, and uses the current value at that time as the stable current value as the reference holding means. 32a. This stable current value is transmitted to the comparison circuit 33 and is compared with the subsequent current measurement value by the comparison circuit 33. When the difference is greater than or equal to the reference value y, it is determined that the drive current is abnormal, a stop signal is transmitted from the comparison circuit 33 to the drive circuit 34, and the drive motor 19 is stopped.
In this embodiment, the reference value x is 5%, and the reference value y is 1.1 times the stable current value (current value representing the “stable torque value” in FIG. 1). Since it differs depending on the type of dishwasher, it is necessary to select an appropriate value for each model.

The flow of this detection system is as shown in FIG.
Whether or not the current change rate (differential value) is below a predetermined reference is determined by the current stability determining means 32 (S1), and if yes, it is determined whether the subsequent fluctuation of the current value is greater than or equal to a predetermined value (S2). At this time, the drive circuit 34 is stopped (S3), whereby the drive motor 19 is stopped (S4), and the drawing operation of the cleaning tank 15 is stopped (S5). In this case, the drive motor can be forcibly stopped by a reverse current, but this is not always necessary from the viewpoint of ensuring safety.

Another example of this detection system for detecting increased drag resistance is shown in the block diagram of FIG.
In this other example, the current stability determination means 40 determines whether the current has stabilized based on the reference value of the rate of change held in the reference value holding means 41, and thereafter, the current measurement value is also obtained by the differentiation circuit 31. Differentiation is performed, and the differential value is determined based on the reference value of the rate of change held in the reference value holding means 41 to determine whether the current value is abnormal.

  By the way, since the driving current fluctuates slightly even in the current stable region, the rate of change may exceed the reference value (for example, 5%) even in a normal state. On the other hand, an increase in the pull-in resistance at the moment when the operator slammed his hand during the pull-in operation and touches the tableware or the tableware basket, or an increase in the pull-in resistance at the moment when the tableware collides with the dishwasher body is stable running (constant speed running). It has been experimentally confirmed that it instantaneously exceeds 10% of the hourly stable current value (for example, 0.1 A). Since the fluctuation range is different depending on the model of each dishwasher, the current abnormality determination standard may be appropriately selected, for example, 1.1 times the change rate standard value.

As described above, the invention for detecting an abnormal change in the drive torque of the drive motor 19 and stopping the drive motor has been described. However, since the moving speed of the cleaning tank is instantaneously reduced at the time of the abnormality, the deceleration is detected and driven. The motor can also be stopped.
That is, after the cleaning tank is started and the moving speed reaches a predetermined speed, when the moving speed of the cleaning tank decreases to a predetermined speed (for example, 90% of the predetermined speed) in the constant speed control state, it is determined as abnormal, Stop the drive motor.
When detecting the moving speed of the cleaning tank by the rotational speed of the drive motor while accelerating the moving speed of the cleaning tank to a predetermined speed, and then applying this pulling abnormality detection method to those that control pulling at a constant speed Further, it is only necessary to change the pull-in control means a little, and there is also an advantage that the response is quick because it directly reacts to the abnormal deceleration in a control state at a constant speed. However, when applying the pull-in abnormality detection method to a drawer type dishwasher that does not perform constant speed control by detecting the rotational speed of the drive motor, the washing tank in the washing tank torque stable region (see FIG. 1) It is necessary to newly provide a sensor for detecting the moving speed (for example, a rotational speed sensor of a driving motor or a moving speed sensor of a washing tub) in the dishwasher body.
Further, when an abnormality is detected at the time of pulling in, the drive motor may be reversed to automatically push out the cleaning tank.

  As described above, the operation of the embodiment has been described on the assumption of the pull-in operation. However, the pull-out operation is almost the same, and the description thereof is omitted. In this case, however, the operation flow in FIG. 3 is “stop washing tank drawing” in step S5 in FIG.

These are figures which show the change of the drive current value during the washing tank drawing-in operation | movement of an Example. FIG. 3 is a block diagram of a system for detecting an abnormal pulling resistance of the cleaning tank according to the embodiment. These are the flowcharts of the detection system of an Example. These are block diagrams of the other examples of the detection system of an Example. FIG. 2 is a cross-sectional view of a conventional dishwasher. FIG. 2 is a block diagram of a control system for a dishwasher.

Explanation of symbols

3: Tableware 4: Tableware basket 14: Dishwasher body 15: Washing tank 15k: Inner lid 15p: Packing 18: Rack gear 19: Drive motor 19a: Pinion 23: Front door 24: Handle 30: Drive ammeter 31: Differentiation circuit 32 40: current stability determination means 32a: reference value holding means 33: comparison circuit 34: drive circuit 41: change rate reference value holding means 51: operation unit 52: control means 53: load drive circuit

Claims (7)

In a pull-out dishwasher where the washing tank is operated with a drive motor,
It has a pull-in resistance detection means for detecting an increase in the pull-in resistance of the cleaning tank,
When the pull-in resistance detection means detects a pull-in resistance increase beyond a predetermined value during the pull-in operation at a constant speed, the drive motor drive by the drive circuit is stopped,
A pull-out dishwasher that stops the retraction of the washing tub.   2. The drawer type dishwasher according to claim 1, wherein the pull-in resistance detecting means is a current detecting means of a driving motor.   2. A drawer type dishwasher according to claim 1, wherein the pull-in resistance detecting means is a rotational speed sensor of a driving motor or a moving speed sensor of a washing tub. In a pull-out dishwasher where the washing tank is operated with a drive motor,
Drive torque detection means for the drive motor,
Having drive torque stability detecting means;
Having torque comparison means;
The drive torque detected by the drive torque detection means is evaluated by the drive torque stability detection means to confirm that it is almost stable, and the stable torque value at that time is measured.
In the torque stability range from when the torque stability is confirmed until the drive stops due to the completion of pull-in, the measured torque value is compared with the torque stable value by the torque comparison means, and when the difference is greater than the reference value, it is determined that the torque is abnormal. A pull-out dishwasher in which the drive motor is stopped when a drive torque abnormality is confirmed.   The drive torque detection means is a drive current measurement meter of the drive motor, the torque stability detection means is an arithmetic circuit that differentiates the current measurement value and compares the differential value with a reference value, and the torque comparison means calculates the current measurement value. The drawer-type dishwasher according to claim 4, which is a comparison circuit for comparing with a reference value. In a pull-out dishwasher where the washing tank is operated with a drive motor,
Having a drive ammeter for the drive motor,
Having a drive current differentiating means,
Having current stability detection means;
Having a comparison means;
It is confirmed that the drive current is stabilized almost constant by the current stability detection means,
In the torque stable range from the confirmation of the stability of the drive current to the stop of the drive due to the completion of the drawing of the cleaning tank, the drive current value is differentiated by the differentiation circuit, and the differential value is compared with the reference value by the comparison circuit. A drawer-type dishwasher in which a drive motor is stopped when a current abnormality is determined and a drive current abnormality is confirmed. 4. The pull-out type dishwasher according to claim 3, wherein when the pull-in speed is constant and the pull-in of the washing tank is controlled, the driving motor is stopped by the drive circuit when the pull-in speed of the washing tank is 90% or less of the pull-in speed. Machine.

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