JP4010069B2 - Water heater - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a water heater, and more particularly, relates to a control technique of a stepping motor for driving a valve device for performing flow control in the water heater.
[0002]
[Prior art]
Conventionally, in a hot water supply device, a large number of valve devices are used on the piping path in order to adjust the flow rate of hot water flowing in the piping path of the hot water supply device. In order to control, a stepping motor is frequently used as a drive source of the valve device.
[0003]
Here, a schematic configuration of the hot water supply apparatus is shown in FIG. In the hot water supply apparatus shown in FIG. 1, a water inlet side pipe 2 and a hot water outlet side pipe 3 are connected to both ends of the heat exchanger 1, and between the water inlet side pipe 2 and the hot water outlet side pipe 3. In addition, the bypass line 4 that bypasses the heat exchanger 1 is disposed, whereby the piping path of the hot water supply apparatus is configured.
[0004]
The bypass pipe 4 and the hot water outlet side pipe 3 are provided with valve devices (bypass flow rate adjusting valve 5 and overflow servo valve 6) for adjusting the flow rate of hot water flowing in the respective pipes. The operations of the bypass flow rate adjusting valve 5 and the excessive outflow servo valve 6 are controlled by a control means 7 provided in the hot water supply apparatus main body.
[0005]
By the way, although the valve device provided on such a piping path is driven by the stepping motor as described above, the rotation speed of each stepping motor of each valve device is fixed at a constant speed.
[0006]
For example, in the overflow servo valve 6, the rotation speed is a speed at which the flow rate of the hot water flowing in the tapping side pipe line 3 can be controlled by opening and closing the valve of the valve device linked to the stepping motor, in other words, The rotation speed of the stepping motor is fixed at a relatively slow constant speed that emphasizes torque rather than speed so that the valve can be opened and closed against water flow in the hot water side pipe 3 (for example, Taking an actual hot water supply device as an example, the frequency of pulses applied to the stepping motor that drives the valve device is fixed to about 333 pulses / second).
[0007]
[Problems to be solved by the invention]
However, the control method in which the rotational speed of the stepping motor is controlled at a predetermined constant speed as described above has the following problems, and improvement has been desired.
[0008]
That is, taking the case of the overflow servo valve 6 as an example, the rotational speed of the stepping motor is constant so that the flow rate can always be controlled regardless of the flow rate of the hot water flowing in the hot water side pipe 3. The speed is set to a relatively slow speed with an emphasis on rotational torque, but when the stepping motor is driven for purposes other than the above-described flow rate control (for example, position reset of the stepping motor or hot water heated by the heat exchanger 1) Even when the stepping motor is required to operate at a speed higher than the torque, such as when the overflow servo valve 6 is fully closed to drop the water into the bathtub not shown in the drawing, Since it was controlled at the same speed as the time, there was a problem that it took time to shift the position to the fully closed state.
[0009]
This also requires a lot of time (for example, about 25 seconds) for the position reset to be performed when a motor abnormality is detected. For this reason, the motor needs to be returned to the normal operation during the abnormality detection operation (position reset). Occurrence of a case is conceivable, and in that case, a control problem such that complicated control processing is required for the return operation of the motor is caused.
[0010]
The present invention has been made in view of such conventional problems, and its object is to provide a stepping motor used as a drive source for the valve device when the valve device is operated for purposes other than flow rate control. An object of the present invention is to provide a hot water supply device that smoothly controls the valve device by driving the valve at a high speed.
[0011]
[Means for Solving the Problems]
In order to achieve the above object, a hot water supply apparatus according to the present invention includes a water amount sensor for detecting the amount of water passing through the water inlet side pipe line and a water inlet side pipe line and a hot water outlet side pipe line connected to both ends of the heat exchanger. In addition to a flow rate adjusting valve device driven by a stepping motor on a piping path through which hot water passes, a control means for controlling the valve device is provided, and the control means comprises: When water flow exceeding the minimum operating water flow rate required for burning the burner of the heat exchanger is detected in the water flow sensor, the rotational torque of the stepping motor is sufficient to resist water flow. While outputting a speed reference signal, if only a flow rate less than the minimum operating flow rate is detected, a higher speed reference signal is output than when a flow rate exceeding the minimum operating flow rate is detected. Characterized in that it is configured urchin.
[0015]
That is, a valve device that is driven by a stepping motor on the piping path of the hot water supply device and is controlled by the control means of the hot water supply device may be provided. By switching the speed reference signal to be applied depending on whether the output of the water sensor is above or below the minimum operating flow rate required to burn the heat exchanger burner (MOQ on or off) and when the flow rate control in which a predetermined torque is required, the rotation speed of the stepping motor and otherwise it is configured to switch the opening and closing speed of the turn valve device.
[0018]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, a case where the stepping motor control method according to the present invention is applied to control of a stepping motor used in a valve device of a hot water supply apparatus will be described in detail with reference to FIGS. 1 and 2.
[0019]
The hot water supply apparatus is a hot water supply apparatus having a configuration in which a stepping motor, which is a drive source of a valve device arranged on a piping path through which hot water passes, is controlled by control means of the hot water supply apparatus. The basic configuration is the same as that of the conventional hot water supply apparatus shown in FIG. Therefore, in the following description, the same components as those of the conventional hot water supply device are denoted by the same reference numerals and description thereof is omitted.
[0020]
This hot water supply apparatus is composed mainly of a heat exchanger 1, a water inlet side pipe 2, a hot water outlet side pipe 3, a bypass pipe 4, a bypass flow rate adjustment valve 5, an excessive outflow servo valve 6, and a control means 7. The control means 7 is for controlling the operation of each part of the hot water supply device, and is composed of a microcomputer that operates according to a predetermined program.
[0021]
The control means 7 is obtained from information obtained from various sensors (in the illustrated example, a water thermistor, a water amount sensor, a can body thermistor, and a hot water thermistor) provided in each part on the piping path, or from a remote controller (not shown). Operation control of each part of the hot water supply apparatus is performed based on various setting information (for example, hot water supply set temperature and hot water supply amount).
[0022]
FIG. 2 is a block diagram showing the control configuration of the overflow servo valve 6 (or bypass flow rate adjustment valve 5) by the control means 7.
[0023]
As shown in FIG. 2, the overflow servo valve 6 includes a stepping motor 61 controlled by the control means 7 and a valve device main body 62 driven by the stepping motor 61. Further, the stepping motor 61 includes a motor control unit 63 and a pulse motor unit 64, and the pulse motor unit 64 and the valve device main body 62 are configured to work together.
[0024]
Specifically, the stepping motor 61 receives the speed reference signal (control signal) output as a digital pulse signal from the control means 7 by the motor control unit 63, and according to the received speed reference signal. The motor control unit 63 drives the motor by passing a current through a stator (not shown) of the pulse motor unit 64.
[0025]
By the way, the rotational speed of the stepping motor 61 configured as described above, that is, the operating speed of the valve device main body 62 interlocked with the stepping motor 61 is proportional to the pulse frequency of the speed reference signal output from the control means 7. To increase.
[0026]
In the present invention, the control means 7 for outputting the speed reference signal is configured so that the pulse frequency of the speed reference signal can be switched according to the operation purpose of the stepping motor.
[0027]
That is, since the control means 7 is composed of a microcomputer that operates according to a predetermined control program as a means for controlling the operation of each part of the hot water supply apparatus as described above, a control program to be stored in the control means 7 is produced. In each stage, the speed reference signal is output according to each scene (for example, whether the speed reference signal is output for the purpose of flow control or the speed reference signal is output for other purposes). A program is set to change the pulse frequency of the speed reference signal.
[0028]
Specifically, for example, in the operation control of the excess spill servo valve 6, water flow exceeding the minimum operating water flow rate required for burning the burner (not shown) of the heat exchanger 1 is detected by the water flow sensor. When the flow rate is controlled (when MOQ is ON), a speed reference signal (for example, 333 pulses / second) is output so that the rotational torque of the pulse motor unit 64 is sufficient to resist water flow through the tapping side pipe 3. On the other hand, when only a water flow rate less than the minimum operating water flow rate is detected (for example, when the MOQ is turned off when the water supply is stopped and the position is reset), the valve device main body 62 is driven. In this case, the pulse frequency of the speed reference signal output from the control means 7 is set higher than that during the flow rate control (for example, 333 pulses / Such as) a higher value than, the control program is set according to the operation purpose of the stepping motor 61.
[0029]
That is, by setting the control program in this way, in this embodiment, when controlling the operation of the overflow servo valve 6, when torque is required as in the flow control, and when operating for purposes other than the flow control, When the torque is not a problem as described above (or when the driving speed is prioritized), the speed reference signal supplied to the stepping motor 61 can be switched.
[0030]
Therefore, according to the present invention, when the valve device is driven for a purpose other than the flow rate control, for example, when the position of the motor is reset as an abnormality detection operation of a valve device such as an overflow servo valve of the hot water supply device. The drive speed can be made faster than that during flow control. Therefore, when speed is required rather than torque when driving the motor, the valve device can be driven quickly, and the stepping motor can be appropriately controlled according to its operation purpose.
[0031]
The above-described embodiment is merely a preferred embodiment of the present invention, and the present invention is not limited to this, and various design changes can be made within the scope of the invention.
[0032]
For example, in the above embodiment, the configuration has been described in which the switching of the speed reference signal applied to the stepping motor is switched according to the magnitude of the rotational torque required when the motor rotates. However, the speed reference signal is switched based on other matters. It is also possible. In addition, it is possible to configure the speed reference signal to be switched stepwise in accordance with the amount of water flow in the piping path during flow rate control.
[0033]
Further, in the above embodiment, the speed reference signal is switched by switching the high and low pulse frequencies, but a plurality of speed reference signals are prepared according to the operation purpose of the stepping motor. It is also possible to perform switching in multiple stages.
[0034]
Further, in the above embodiment, the case where the stepping motor control method of the present invention is applied to a hot water supply device has been described. However, the present invention is not limited to a hot water supply device, and any device other than a hot water supply device can be used as long as the valve device is driven by a stepping motor. It can be applied to other devices. Moreover, even when applied to a hot water supply apparatus, the configuration of the piping path may be other than that shown in FIG. 1, and may be connected to, for example, a piping path of a hot water supply and heating system.
[0035]
【The invention's effect】
As described above in detail , according to the hot water supply apparatus of the present invention, the signal given as the speed reference to the stepping motor used as the drive source of the valve device in the hot water supply apparatus causes the burner of the heat exchanger to burn in the water amount sensor. When the water flow exceeding the minimum operation water flow required for the operation is detected (when MOQ is ON), the rotation torque of the stepping motor is a speed reference signal that is sufficient to resist water flow. When only a water flow rate less than the minimum operating water flow rate is detected (when MOQ is off) , the valve device has a higher speed reference signal than when a water flow exceeding the minimum operating water flow rate is detected. The rotational speed of the stepping motor can be moderated according to the use state of the motor, and as a result, an appropriate rotational speed according to the operation purpose can be obtained.
[Brief description of the drawings]
FIG. 1 is an explanatory diagram showing a schematic configuration of a hot water supply apparatus according to the present invention.
FIG. 2 is a block diagram showing a control configuration of an excessive outflow servo valve of the hot water supply apparatus.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Heat exchanger 2 Inlet side line 3 Hot water outlet side line 4 Bypass line 5 Bypass flow control valve (valve device)
6 Overflow servo valve (valve device)
7 Control means 61 Stepping motor 62 Valve device main body 63 Motor control section 64 Pulse motor section

Claims (1)

In the hot water supply apparatus provided with a water amount sensor for detecting the amount of water passing through the water inlet side pipe line and the water inlet side pipe line and the hot water outlet side pipe line are connected to both ends of the heat exchanger,
At least a flow rate adjusting valve device driven by a stepping motor is provided on a piping path through which hot water passes, and a control means for controlling the valve device is provided, and the control means is a heat exchanger in the water amount sensor. When a water flow exceeding the minimum working water flow amount necessary for burning the burner is detected, a speed reference signal is output so that the rotational torque of the stepping motor is sufficient to resist water flow. When a flow rate less than the minimum operating flow rate is detected, a speed reference signal higher than that when a flow rate equal to or higher than the minimum operating flow rate is detected is output. Hot water supply device.

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