Hot water supply device

Abstract

In a hot water supply device provided with a valve which performs opening control by taking a stepping motor as a driving source, the frequency of rotation position initialization processing of the stepping motor is made appropriate. On the basis of the comparison between the operation parameter of the hot water supply device and the determination value, the controller (10) resets the position of the stepping motor (150), which is the drive source of the valve (90). When the position reset is executed, in accordance with a detection signal (LS) generated when the rotation position (MPc) reaches the reference position, when the control value of the rotation position (MPc) is initialized, and when the magnitude of the error between the control value before initialization and the reference position is larger than the reference range, the determination value is changed so that the execution frequency of the position reset is increased.

Description

Technical Field

[0001] The present invention relates to a hot water supply device, and more particularly, to a hot water supply device including a valve whose opening degree is controlled by being driven by a stepping motor. Background Art

[0002] Japanese Patent No. 4090413 (Patent Document 1) describes a structure in which each hot water supply device has a flow control valve driven by a stepping motor (pulse motor) in a connected hot water supply system using a plurality of hot water supply devices connected in parallel. The stepping motor is advantageous in terms of cost including ease of control because the rotational position (angle) of the stepping motor changes in open loop control according to the input of digital pulses.

[0003] In Patent Document 1, the outflow rate of hot water from each hot water supplier is controlled by the opening of each flow regulating valve. Furthermore, Patent Document 1 describes the following: position resetting (rotation position initialization processing) is performed on each flow regulating valve to eliminate the position deviation (step loss) of the stepping motor. By periodically performing position resetting, the error between the actual valve opening and the valve opening recognized by the control unit caused by the deviation of the rotation position of the stepping motor can be suppressed.

[0004] [Prior art literature]

[0005] [Patent Document]

[0006] [Patent Document 1] Japanese Patent No. 4090413 Summary of the invention

[0007] [Problems to be solved by the invention]

[0008] As described in Patent Document 1, in the position reset, a pulse signal is applied to the stepping motor to change the valve opening degree until a hard detection signal generated when the valve opening degree reaches a reference opening degree is received.

[0009] Therefore, if the frequency of position resetting is too low, there is a concern about the error in the valve opening degree, while if the frequency is too high, there is a concern about problems such as an increase in power consumption of the stepping motor and a decrease in device durability.

[0010] The present invention has been made to solve such a problem, and an object of the present invention is to execute a rotation position initialization process of a stepping motor at an appropriate frequency in a hot water supply device provided with a valve whose opening is controlled by a stepping motor as a driving source.

[0011] [Technical means to solve the problem]

[0012] In one aspect of the present invention, a hot water supply device is provided. The hot water supply device includes a control valve and a controller. The control valve is disposed in the fluid flow path and controls the opening degree with a stepping motor as the driving source. The controller controls the rotational position of the stepping motor to control the opening degree of the control valve. The stepping motor is configured to output a detection signal to the controller when the rotational position reaches a predetermined reference position. The controller continuously generates a control signal for driving the rotational position of the stepping motor to the reference position based on the comparison between the operation parameters of the hot water supply device and a determination value until the detection signal is received from the stepping motor, thereby performing the rotational position initialization process. Further, when performing the rotational position initialization process, the controller, upon receiving the detection signal, initializes the control value of the rotational position to a value corresponding to the reference position, and when the absolute value of the error between the control value before initialization and the reference position exceeds and is greater than a predetermined reference range, changes the determination value to increase the execution frequency of the rotational position initialization process.

[0013] [Effects of the Invention]

[0014] According to the present invention, in a hot water supply device provided with a valve that controls the opening degree using a stepping motor as the driving source, the rotational position initialization process of the stepping motor can be performed at an appropriate frequency. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a block diagram for explaining the structure of the hot water supply device of the present embodiment.

[0016] Figure 2 It is for Figure 1 The block diagram for explaining the drive structure of the flow rate adjustment valve shown.

[0017] Figure 3 It is a conceptual diagram for explaining the control of the rotational position of the stepping motor.

[0018] Figure 4 It is a conceptual diagram for explaining the position reset of the stepping motor.

[0019] Figure 5 It is a flowchart for explaining the control process of the position reset.

[0020] Figure 6 It is a flowchart for explaining the setting process of the determination value for the position reset.

[0021] Figure 7 It is a conceptual diagram for explaining an example of setting the determination value corresponding to the error at the time of position reset.

[0022] Figure 8 It is a block diagram for explaining a modification of the structure of the hot water supply device of the present embodiment.

[0023] [Description of Signs]

[0024] 1A, 1B: Hot water supply device

[0025] 10: Controller

[0026] 11: Water inlet port

[0027] 12: Hot water outlet port

[0028] 13: Circulation port

[0029] 15: Table

[0030] 20: Water inlet path

[0031] 21: Check valve

[0032] 22: Bypass path

[0033] 23: Circulation path

[0034] 25: Hot water outlet path

[0035] 26, 27, 125: Connection points

[0036] 30: Combustion mechanism

[0037] 40: Heat exchanger

[0038] 71 - 73: Temperature detectors

[0039] 75: Flow detector

[0040] 80: Circulation pump

[0041] 90: Flow control valve

[0042] 100: Housing

[0043] 101 - 103: Characteristic lines

[0044] 110: Water inlet pipe

[0045] 120: Hot water outlet pipe

[0046] 130: Circulation pipe

[0047] 150: Stepper motor

[0048] 155: Reference position detection mechanism

[0049] 200: Hot water supply tap

[0050] LS: Detection signal

[0051] MPc: Rotation position (hard position)

[0052] MPr: Reference value (reference position)

[0053] MPs: Soft position (control value)

[0054] Nbr: Count value

[0055] Nm: Number of pulses

[0056] Nmax: Upper limit value (judgment value)

[0057] Nmin: Lower limit value (judgment value)

[0058] Nr: Judgment value (position reset condition)

[0059] Nx, Ny: Specified values

[0060] PS1 to PSn: Pulse signals

[0061] Qf: Flow rate detection value

[0062] Tb: Tank body temperature

[0063] Th: Hot water outlet temperature

[0064] Tw: Inlet water temperature Detailed implementation manners

[0065] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In addition, the same or corresponding parts in the drawings are denoted by the same reference numerals, and the description thereof will not be repeated in principle.

[0066] Figure 1 is a block diagram for explaining the structure of the hot water supply device 1A of the present embodiment.

[0067] Refer to Figure 1 , the hot water supply device 1A has: a water inlet port 11 connected to the water inlet pipe 110, a hot water outlet port 12 connected to the hot water outlet pipe 120, and a circulation port 13 connected to the circulation pipe 130. Further, the hot water supply device 1A includes a controller 10, a water inlet path 20, a check valve 21, a bypass path 22, a circulation path 23, a hot water outlet path 25, a combustion mechanism 30, a heat exchanger 40, a circulation pump 80, and a flow rate adjustment valve 90 accommodated in a housing 100.

[0068] The water inlet path 20 is formed between the water inlet port 11 and the input side (upstream side) of the heat exchanger 40 via a check valve 21. The combustion mechanism 30 typically includes a burner that generates heat from the combustion of gas, oil, or the like. The heat exchanger 40 uses the heat generated by the combustion mechanism 30 to heat the low-temperature water (fluid) introduced through the water inlet path 20, causing the temperature to rise. The combustion mechanism 30 and the heat exchanger 40 constitute an embodiment of a "heating mechanism".

[0069] The hot water outflow path 25 is formed between the output side (downstream side) of the heat exchanger 40 and the hot water outflow port 12. The bypass path 22 connects between the water inlet path 20 and the hot water outflow path 25 without passing through the heat exchanger 40. The bypass path 22 is configured to connect a portion downstream of the connection point 27 between the upstream side (input side) of the heat exchanger 40 and the circulation path 23 ( Figure 1 which is the location where the flow rate adjustment valve 90 is disposed), and a portion upstream of the connection point 125 on the downstream side (output side) of the heat exchanger 40 (connection point 26). By controlling the opening degree of the flow rate adjustment valve 90 by the controller 10, the ratio of the flow rate of the heat exchanger 40 to the flow rate of the bypass path 22 is adjusted. Thus, at least a part of the fluid flowing through the flow rate adjustment valve 90 is heated by the heat exchanger 40 (heating mechanism).

[0070] A temperature detector 71 is disposed in the water inlet path 20. The temperature detector 71 detects the water inlet temperature Tw before heating by the heat exchanger 40. In contrast, temperature detectors 72 and 73 are disposed in the hot water outflow path 25. The temperature detector 72 is disposed downstream of the connection point 26 between the hot water outflow path 25 and the bypass path 22, and detects the hot water outflow temperature Th. On the other hand, the temperature detector 73 is disposed upstream of the connection point 26 and detects the tank temperature Tb corresponding to the output temperature from the heat exchanger 40. The respective fluid temperatures detected by the temperature detectors 71 to 73 are input to the controller 10.

[0071] Furthermore, a flow rate detector 75 is provided in the hot water supply device 1A. For example, the flow rate detector 75 is disposed downstream of the connection point 27 between the water inlet path 20 and the circulation path 23, and the flow rate adjustment valve 90 located at the branch point between the water inlet path 20 and the bypass path 22, and is configured to detect the flow rate (tank flow rate) of the object to be heated in the heat exchanger 40. The flow rate detection value Qf based on the flow rate detector 75 is input to the controller 10.

[0072] When the hot water supply faucet 200 is opened and the hot water supply destination performs hot water supply use, due to the supply pressure of the cold water, the cold water is introduced into the water inlet path 20. Correspondingly, when the operation switch of the hot water supply device 1A is turned on and the flow detector 75 detects a flow rate exceeding the minimum operating flow rate (Minimum Order Quantity, MOQ), the controller 10 turns on the combustion mechanism 30, thereby starting the hot water supply operation. In addition, the hot water supply faucet 200 is shown as a representative example of the "hot water supply destination" of the hot water supply device 1A. The hot water supply destination may also include an electromagnetic valve that opens / closes the hot water outflow to a bathtub or the like, and is not limited to being directly opened / closed by a user operation. When the hot water supply faucet 200 is closed and the hot water supply destination stops hot water supply use, the cold water is not introduced into the water inlet path 20. Correspondingly, the detected value of the flow detector 75 decreases compared to the minimum operating flow rate (MOQ), and accordingly the controller 10 turns off the combustion mechanism 30, thereby ending the hot water supply operation.

[0073] During the hot water supply operation, the high-temperature water heated by the combustion mechanism 30 and the heat exchanger 40 is mixed with the cold water that has passed through the bypass path 22, and then is output from the hot water outflow port 12 to the hot water supply faucet 200 through the hot water outflow pipe 120. During normal hot water supply operation, the controller 10 stops the circulation pump 80, and the fluid temperature (hot water outflow temperature Th) detected by the temperature detector 72 is controlled to the hot water supply set temperature Tr input to a remote controller (not shown). The controller 10, which is an embodiment equivalent to the "controller", is typically configured as a microcomputer.

[0074] In the hot water supply device 1A, a part of the cold water bypasses the heat exchanger 40 and remains in an unheated state, and is mixed downstream of the heat exchanger 40, thereby supplying hot water at an appropriate temperature from the hot water outflow port 12. Therefore, the output temperature (tank temperature) of the heat exchanger 40 (heating mechanism) can be made higher than the hot water supply set temperature Tr. Thereby, the drain generated by the exhaust gas of the combustion mechanism 30 being cooled on the surface of the heat exchanger 40 can be suppressed.

[0075] The controller 10 can perform hot water outflow temperature control by combining the control based on the heating amount (generated heat) of the combustion mechanism 30 and the control based on the bypass flow rate ratio of the flow rate adjustment valve 90.

[0076] In the hot water supply device 1A, when the hot water supply operation for supplying hot water is stopped by closing the hot water supply faucet 200 or the like, the temperature of the fluid remaining in the hot water outflow path 25 and the hot water outflow pipe 120 decreases. Therefore, there is a concern that it takes time until hot water of an appropriate temperature is supplied to the hot water supply faucet 200 after the start of the next hot water supply operation. Therefore, in the hot water supply device 1A, an immediate hot water operation function for quickly supplying high-temperature water after the start of the hot water supply operation is provided by arranging a circulation port 13, a circulation path 23, and a circulation pump 80.

[0077] The circulation path 23 is formed between the circulation port 13 and the water inlet path 20 (connection point 27). The circulation pump 80 is inserted and connected in the circulation path 23. Alternatively, the circulation pump 80 may also be inserted and connected to the circulation pipe 130 outside the housing 100. The operation and stop of the circulation pump 80 are controlled by the controller 10.

[0078] For example, during the period when the immediate hot water operation mode is turned on by a switch operation or a timer setting, if hot water supply is not used and the fluid temperature (e.g., the tank temperature Tb and / or the hot water outflow temperature Th detected by the temperature detectors 72 and 73) is lower than the immediate hot water start determination temperature (e.g., set to be a specified temperature lower than the hot water supply set temperature), the immediate hot water operation can be started accordingly.

[0079] The immediate hot water operation is achieved as follows: When the use of hot water supply from the hot water supply faucet 200 or the like is stopped, the immediate hot water circulation path including the heat exchanger 40 (heating mechanism) is formed by the operation of the circulation pump 80. The immediate hot water circulation path is composed of a loop that starts from the circulation port 13, passes through the circulation path 23, the water inlet path 20 (downstream side of the connection point 27), the heat exchanger 40, the hot water outflow path 25, the hot water outflow port 12, and the hot water outflow pipe 120 (upstream side of the connection point 125), and the circulation pipe 130 and returns to the circulation port 13.

[0080] When the immediate hot water circulation path is formed by the operation of the circulation pump 80, the combustion mechanism 30 operates when the flow detection value Qf of the flow detector 75 exceeds the MOQ. Thus, the hot water in the immediate hot water circulation path is heated. When the fluid temperature in the immediate hot water circulation path (e.g., the water inlet temperature Tw or the hot water outflow temperature Th detected by the temperature detector 71 or the temperature detector 72) reaches the immediate hot water end determination temperature (e.g., the hot water supply set temperature), the heating by the combustion mechanism 30 is stopped and the circulation pump 80 is stopped, thereby ending the immediate hot water operation.

[0081] In the hot water supply device 1A, the controller 10 performs temperature control that combines control based on the bypass ratio of the flow rate adjustment valve 90, thereby improving the control responsiveness of the hot water outlet temperature. On the other hand, when an error occurs in the opening degree of the flow rate adjustment valve 90 and an error from the set value occurs in the bypass ratio, there is a concern that the controllability of the hot water outlet temperature may decrease.

[0082] Figure 2 shows the drive structure of the flow rate adjustment valve 90 for controlling the bypass ratio.

[0083] Referring to Figure 2 , the opening degree of the flow rate adjustment valve 90 changes in conjunction with the rotational position (angle) MPc of the stepping motor 150.

[0084] Since the bypass ratio, which is the flow rate ratio of the bypass path 22, is determined by the opening degree of the flow rate adjustment valve 90, a table 15 that defines the correspondence between the rotational position of the stepping motor 150 and the opening degree of the flow rate adjustment valve 90, and the correspondence between the opening degree of the flow rate adjustment valve 90 and the bypass ratio is stored in the controller 10.

[0085] After calculating the bypass ratio for controlling the hot water outlet temperature Th to the hot water supply set temperature Tr, the controller 10 controls the rotational position MPc of the stepping motor 150 to control the opening degree of the flow rate adjustment valve 90, in order to achieve the calculated bypass ratio.

[0086] The controller 10 outputs polyphase pulse signals PS1 to PSn to the stepping motor 150. For example, through the pulse signals PS1 to PSn, positive pulses with an increasing number of pulses and negative pulses with a decreasing number of pulses can be input to the stepping motor 150. The pulse signals PS1 to PSn correspond to an embodiment of the "control signal" of the stepping motor 150.

[0087] Figure 3 is a conceptual diagram for explaining the control of the rotational position of the stepping motor 150.

[0088] As Figure 3 shown, the rotational position MPc of the stepping motor 150 changes in proportion to the number of pulses Nm that increases or decreases through the input of positive or negative pulses. For example, when changing the rotational position MPc in the direction of increasing the bypass ratio along the upward direction of the vertical axis, the pulse signals PS1 to PSn are generated from the controller 10 to input positive pulses to the stepping motor 150.

[0089] In addition, Figure 3 continuously represents the relationship between the number of pulses Nm and the rotational position MPc as a straight line, but in reality, the rotational position MPc represents a discrete characteristic, that is, every time the number of pulses Nm changes by 1, it changes by a prescribed scale amount.

[0090] The controller 10 for the stepping motor 150 can identify Figure 3 the number of pulses Nm according to the cumulative values of the positive and negative pulse numbers, and thus can grasp the soft position MPs equivalent to the rotation position MPc of the "control value" according to the number of pulses Nm and the scale amount.

[0091] The controller 10 can use the tank temperature Tb, the inlet water temperature Tw, and the hot water supply set temperature Tr to calculate a command value for the bypass flow ratio for setting the hot water outlet temperature Th to the hot water supply set temperature Tr. The command value can also be calculated in combination with feedback control based on the deviation between the hot water outlet temperature Th and the hot water supply set temperature Tr.

[0092] When obtaining the target value of the rotation position of the stepping motor 150 corresponding to the opening degree of the flow control valve 90 for realizing the calculated bypass ratio, the controller 10 generates pulse signals PS1 to PSn for the stepping motor 150 to make the soft position MPs (control value) coincide with the target value.

[0093] On the other hand, since the rotation position MPc of the stepping motor 150 is not feedback-controlled, there is a possibility of deviation (out-of-step) between the soft position MPs identified by the cumulative number of pulses and the actual rotation position MPc. Therefore, the position reset of the stepping motor 150, which is an embodiment of the "rotation position initialization process", is periodically executed.

[0094] Refer again to Figure 2 , a reference position detection mechanism 155 is provided on the stepping motor 150. The reference position detection mechanism 155 is a hardware that generates a detection signal LS when the rotation position (angle) reaches a specified reference position. The reference position detection mechanism 155 may typically include a limit switch. The reference position can be determined, for example, as corresponding to the rotation position of the stepping motor 150 at an opening degree corresponding to the fully closed or fully open state of the flow control valve 90.

[0095] Figure 4 shows a conceptual diagram for explaining the position reset of the stepping motor.

[0096] Figure 4 The horizontal axis of is the soft position MPs grasped by the controller 10, and the vertical axis is the actual rotation position (hereinafter also referred to as "hard position") MPc of the stepping motor 150.

[0097] When the controller 10 executes the position reset, in order to drive the rotation position of the stepping motor toward the reference position, it generates pulse signals PS1 to PSn to change the soft position MPs toward the reference value MPr corresponding to the reference position. When the actual rotation position of the stepping motor 150 becomes the reference position, Figure 2 The detected signal LS shown is input to the controller 10.

[0098] After receiving the detected signal LS, the controller 10 initializes (resets) the soft position MPs at that time point to the reference value MPr. Thereafter, starting from the initialized soft position MPs (= MPr), the soft position MPs are updated in accordance with the scale amount corresponding to the accumulation of positive or negative pulses.

[0099] As shown by the characteristic line 101, in the case where there is no error ΔMP between the soft position MPs and the hard position MPc, after the controller 10 performs position reset, it receives the detected signal LS when MPs = MPr. In this case, since the error ΔMP = 0, the soft position MPs maintain the current value.

[0100] In contrast, in the case where an error ΔMP as shown by the characteristic line 102 occurs between the soft position MPs before initialization and the hard position MPc, when MPs = M1 before the soft position MPs reach the reference value MPr, the controller 10 receives the detected signal LS. In this case, the error ΔMP = M1 - MPr (ΔMP < 0).

[0101] Conversely, in the case where an error ΔMP as shown by the characteristic line 103 occurs between the soft position MPs before initialization and the hard position MPc, when MPs = M2 after the soft position MPs reach the reference value MPr, the controller 10 receives the detected signal LS. In this case, the error ΔMP = M2 - MPr (ΔMP > 0).

[0102] As in the characteristic line 102 and the characteristic line 103, when the error ΔMP is not 0, the soft position MPs are initialized from M1 or M2 to the reference value MPr.

[0103] Figure 5 It is a flowchart for explaining the control process of position reset. Figure 5 The control process shown is repeatedly started by the controller 10.

[0104] Refer to Figure 5 , the controller 10 determines whether the position reset condition is established through step (hereinafter, also simply referred to as "S") 110. The determination of S110 is executed by comparing the specified operation parameters of the hot water supply device 1A with the determination value.

[0105] For example, the operation parameter value in S110 can be set as the number of operations of the combustion mechanism 30. In this case, in S110, when the count value Nbr of the combustion times, which increases by 1 each time the combustion mechanism 30 changes from off to on, reaches the determination value Nr, it is determined as yes (YES) determination (Nbr ≧ Nr), and it is determined as no (NO) determination when Nbr < Nr.

[0106] When the position reset condition is satisfied (when the determination in S110 is YES), the controller 10 performs the Figure 4 position reset described in. In S130, in response to the reception of the detection signal LS, the soft position MPs is initialized to the reference value MPr, and using the value of the soft position MPs before initialization, the Figure 4 error ΔMP shown in is calculated. Further, when performing the position reset, the count value Nbr, which is the operation parameter of the position reset condition, is cleared to zero.

[0107] Furthermore, the controller 10, through S140, sets the position reset condition used in the determination (S110) of the subsequent position reset in accordance with the magnitude (|ΔMP|) of the error calculated in S130. As described above, when the position reset condition is determined by the determination value Nr of the count value Nbr of the number of combustion times, the determination value Nr is set in accordance with the magnitude (|ΔMP|) of the error calculated in S130.

[0108] Figure 6 is a flowchart for explaining the setting process of the determination value of the position reset condition based on S140.

[0109] Referring to Figure 6 , the controller 10 compares the magnitude (|ΔMP|) of the error with the reference range defined by the determination value N1 and the determination value N2 through S210 and S220. Thus, as Figure 7 shown, it is determined which of the region R1 (|ΔMP| > N1) larger than the reference range, the region R2 (N2 ≤ |ΔMP| ≤ N1) within the reference range, and the region R3 (|ΔMP| < N2) smaller than the reference range the |ΔMP| belongs to.

[0110] When |ΔMP| belongs to the region R1, that is, when the absolute value of the error is larger than the reference range (N1 to N2), the controller 10 reduces the determination value Nr of the position reset condition by a specified value Nx compared to the current value. By reducing the determination value Nr compared to the current value, the frequency of the position reset can be increased compared to the current situation. That is, the determination value Nr is changed so that the frequency of the position reset increases.

[0111] Among them, the decrease of the determination value Nr is executed within the limit of a predetermined lower limit value Nmin. Specifically, after the decrease of the determination value Nr based on S230, the controller 10 compares the decreased determination value Nr with the lower limit value Nmin through S240. When Nr < Nmin (when the determination in S240 is NO), it is set to Nr = Nmin. On the other hand, when Nr ≥ Nmin (when the determination in S240 is YES), S250 is skipped and the determination value Nr in S230 is maintained. By setting the lower limit value Nmin for the determination value Nr, a limit can be set for the increase in the execution frequency of position reset. That is, although the execution frequency of position reset cannot be directly specified, the upper limit of the execution frequency of position reset can be equivalently set.

[0112] When |ΔMP| belongs to region R3, that is, when the absolute value of the error is smaller than the reference range (N1 to N2), the controller 10 increases the determination value Nr of the position reset condition by a specified value Ny compared to the current value through S270. By increasing the determination value Nr compared to the current value, the frequency of position reset can be reduced compared to the current situation. That is, the determination value Nr is changed to reduce the frequency of position reset.

[0113] Among them, the increase of the determination value Nr is also executed within the limit of a predetermined upper limit value Nmax. Specifically, after the increase of the determination value Nr based on S270, the controller 10 compares the increased determination value Nr with the upper limit value Nmax through S280. When Nr > Nmax (when the determination in S280 is NO), it is set to Nr = Nmax. On the other hand, when Nr ≤ Nmax (when the determination in S280 is YES), S290 is skipped and the determination value Nr in S270 is maintained. By setting the upper limit value Nmax for the determination value Nr, a limit can be set for the decrease in the execution frequency of position reset. That is, although the execution frequency of position reset cannot be directly specified, the lower limit of the execution frequency of position reset can be equivalently set.

[0114] On the other hand, when |ΔMP| belongs to region R2, that is, when the absolute value of the error is within the reference range, the controller 10 maintains the determination value Nr at the current value through S260.

[0115] As a result, as Figure 7 shown, if the absolute value of the error (|ΔMP|) at the time of position reset is larger than the predetermined reference range (between the determination value N1 and the determination value N2), the determination value Nr (i.e., the position reset condition) can be changed to increase the execution frequency of position reset. Thus, in a situation where errors of soft positions MPs (control values) are likely to occur, by performing position reset before the error becomes large, suppression of the opening error of the flow control valve 90 can be achieved.

[0116] Furthermore, if the absolute value of the error during position reset (|ΔMP|) is smaller than a predetermined reference range, the determination value Nr, i.e., the position reset condition, can be changed to reduce the execution frequency of position reset. Thus, in a situation where it is difficult to generate an error in the soft position, by not excessively performing position reset, power consumption can be suppressed, and a reduction in the durability of the device can be suppressed.

[0117] In contrast, when the absolute value of the error during position reset (|ΔMP|) is within the predetermined reference range, the determination value Nr is maintained, and the current execution frequency of position reset is maintained.

[0118] In this way, in the hot water supply device of the present embodiment, in a hot water supply device configured with a valve that controls the opening degree using a stepping motor as a drive source, the execution frequency of position reset can be adjusted according to the magnitude of the error of the control value of the rotational position obtained during position reset. Thus, the position reset (rotation position initialization process) of the stepping motor for controlling the opening degree of the valve can be performed at an appropriate frequency.

[0119] In addition, in the case of preferentially suppressing the opening error, Figure 6 and Figure 7 are deformed, and the determination value Nr of the position reset condition is maintained in the two regions of region R2 and region R3.

[0120] In addition, regarding the operation parameter for determining the position reset condition, it is not limited to the number of operations of the combustion mechanism described above, and various conditions can be set. For example, it is also possible to perform the determination in S110 by comparing the cumulative value of the operation time of the combustion mechanism 30, or the elapsed time since the last execution of position reset, etc. with the determination value. Or, it is also possible to more directly count the number of times of opening degree change of the flow rate adjustment valve 90 and compare it with the determination value as the operation parameter. In these cases, in S140 ( Figure 5 ), according to Figure 7 , the determination value of the position reset condition used in S110 can be set corresponding to the absolute value of the error (|ΔMP|) during position reset, so that the execution frequency of position reset can be increased, decreased, or maintained.

[0121] Next, a modification example of the structure of the hot water supply device of the present embodiment will be further described.

[0122] Figure 8 The block diagram for explaining the structure of the hot water supply device 1B as a modification example of the present embodiment is shown.

[0123] Referring to Figure 8 , the hot water supply device 1B is a model that does not have an instant hot water circulation function, and from Figure 1The hot water supply device 1A omits the configuration of the circulation port 13, the circulation path 23, and the circulation pump 80. The operation of the hot water supply device 1B during hot water supply operation is the same as that of the hot water supply device 1A, and the flow rate adjustment valve 90 is also controlled in the same manner as the hot water supply device 1A. Therefore, in the hot water supply device 1B, the position reset can also be similarly performed for the flow rate adjustment valve 90 that controls the opening degree using a stepping motor.

[0124] In addition, as long as the present embodiment includes a valve that is disposed in the flow path of the fluid and controls the opening degree using a stepping motor, it can be commonly applied to the position reset of the stepping motor regardless of the internal structure of the hot water supply device.

[0125] It should be considered that the embodiments disclosed herein are illustrative rather than restrictive in all respects. The scope of the present invention is shown by the claims rather than by the description, and is intended to include all modifications within the meaning and scope equivalent to the claims.

Claims

1. A hot water supply device, comprising: The control valve is arranged in the flow path of the fluid and uses a stepper motor as a driving source to control the opening; as well as a controller, controlling the rotational position of the stepper motor to control the opening of the control valve, The stepping motor is configured to output a detection signal to the controller when the rotation position reaches a predetermined reference position. In the controller, Based on the comparison between the action parameter of the hot water supply device and the judgment value, a control signal is continuously generated to the stepper motor to drive the rotation position to the reference position until the detection signal is received from the stepper motor, thereby performing a rotation position initialization process, and when the rotation position initialization process is performed, when the detection signal is received, the control value of the rotation position is initialized to a value corresponding to the reference position, and when the absolute value of the error between the control value before initialization and the reference position exceeds and is greater than a predetermined reference range, the judgment value is changed to increase the execution frequency of the rotation position initialization process. 2 . The hot water supply device according to claim 1 , wherein the controller changes the determination value by limiting the execution frequency to not exceed a predetermined upper limit when changing the determination value so as to increase the execution frequency.

3. The hot water supply device according to claim 1, wherein when the absolute value of the error when the controller receives the detection signal during the execution of the rotational position initialization process exceeds and is less than the reference range, the controller changes the determination value to reduce the execution frequency of the rotational position initialization process. 4 . The hot water supply device according to claim 3 , wherein the controller changes the determination value by limiting the execution frequency to not fall below a predetermined lower limit when changing the determination value so as to reduce the execution frequency.

5. The hot water supply device according to any one of claims 1 to 4, wherein the hot water supply device further comprises a heating mechanism, The heating mechanism heats at least a portion of the fluid flowing through the flow path in which the control valve is disposed. The operation parameter includes one of the number of times or the operating time of the heating mechanism, the number of times the opening degree of the control valve is changed, and the elapsed time from the last execution time of the rotational position initialization process.

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