JP7624940B2 - How to control a ventilation fan - Google Patents

Description

This disclosure relates to a ventilation fan that uses a damper to switch between multiple air paths through which air flows inside a housing, and a method for controlling the ventilation fan.

There have been many proposals for ventilation fans with an air passage switching structure. In addition, several proposals have been made for the operation of the damper and the control of the stepping motor that drives the damper. For example, Patent Document 1 discloses a vehicle air conditioning system in which a rotating member is driven by an actuator and abutted against a non-rotating member to detect a reference position, and the abutting operation is performed multiple times at different drive speeds to improve the positional accuracy of the reference position. Stepping motors, which are one type of actuator, are often used when it is necessary to hold the stopped position after the rotor has rotated a certain angle and stopped. When rotating, the rotor position rotates in steps by switching the current in the stator winding, and when the position is held, the poles excited by the current are aligned with the rotor teeth by magnetic force to hold the position. Therefore, stepping motors are generally used with constant current.

JP 2007-314119 A

However, in the vehicle air conditioning system described in Patent Document 1, the stepping motor is excited immediately after being driven a specified distance. This causes the rotor position, i.e., the rotating shaft of the stepping motor, to be held in a state where the damper and gears inside the stepping motor are under high stress. If the rotating shaft is held in a state where it is under stress, a load is placed on the stepping motor, shortening its lifespan.

The present disclosure has been made in consideration of the above, and aims to provide a method for controlling a ventilation fan that can reduce the stress on the rotating shaft and gears of a stepping motor compared to conventional methods.

In order to solve the above-mentioned problems and achieve the object, the present disclosure provides a control method for a ventilation fan including a damper that switches between a circulation air passage connecting the suction port and the outlet and a ventilation air passage connecting the suction port and the outlet by rotating around a rotation shaft inside a housing having an inlet port that draws in indoor air, an outlet port that blows air into the room, and an outlet port that exhausts the air drawn in from the inlet port to the outside, a stepping motor connected to the rotation shaft that drives the damper, and a fan provided inside the housing, the control method including a butting step, a rotating shaft releasing step, and a holding step. The butting step drives the stepping motor to butt the damper against the inside of the housing so that the damper is in a fully open state where the damper blocks the ventilation air passage or in a fully closed state where the damper blocks the circulation air passage. The rotating shaft releasing step cuts off the power supply to the stepping motor to release the state in which the rotating shaft is held. The holding step energizes the stepping motor to excite it so that the rotating shaft is held. When the damper is butted against the inside of the housing, an butting step, a rotating shaft releasing step, and a holding step are carried out successively.

This disclosure has the advantage of being able to reduce the stress on the rotating shaft and gears of the stepping motor compared to conventional methods.

FIG. 1 is a schematic diagram illustrating an example of a structure of a ventilation fan according to a first embodiment; FIG. 1 is a schematic diagram showing an example of the configuration of a damper drive mechanism in a bathroom dryer; A diagram showing an example of the rotation principle of a stepping motor FIG. 4 is a diagram showing an example of a current supply sequence for coils in the stepping motor of FIG. 3 . A diagram showing an example of the state of the air duct when a bathroom dryer is in ventilation operation. A diagram showing an example of the state of the air duct when a bathroom dryer is in heating operation. A diagram showing an example of the state of the air duct during drying operation of a bathroom dryer. A flowchart showing an example of a procedure of a control method for a ventilation blower according to the first embodiment. FIG. 13 is a diagram showing an example of a sequence of energizing coils of a stepping motor in a control method for a ventilation fan according to the first embodiment; FIG. 1 is a schematic diagram showing an example of stresses acting on a rotating shaft and gears in each step of a method for controlling a ventilation fan according to the first embodiment; A flowchart showing an example of a procedure of a control method for a ventilation fan according to a second embodiment. FIG. 13 is a diagram showing an example of a sequence of energizing coils of a stepping motor in a control method for a ventilation fan according to a second embodiment; FIG. 11 is a schematic diagram showing an example of stresses acting on a rotating shaft and gears in each step of a method for controlling a ventilation fan according to a second embodiment; A flowchart showing an example of a procedure of a control method for a ventilation blower according to embodiment 4. FIG. 1 is a block diagram showing an example of a hardware configuration of a control unit provided in a ventilation fan according to embodiments 1 to 4.

Below, the ventilation fan and the control method for the ventilation fan according to the embodiment of the present disclosure are described in detail with reference to the drawings.

Embodiment 1.
First, the overall configuration of the ventilation fan will be described. Fig. 1 is a diagram showing a schematic diagram of an example of the structure of a ventilation fan according to a first embodiment. Here, the description will be given taking as an example a case where the ventilation fan is a bathroom dryer 1. Bathroom dryer 1 is installed through an opening formed in ceiling 51 of bathroom 50, which is an example of a room, passing from bathroom 50 to space above the ceiling 52.

The bathroom dryer 1 comprises a housing 10 and a ventilation duct connection part 13. The housing 10 has an internal air passage, a housing main body part 11 with an open surface facing the bathroom 50, and an orifice 12, which is a bottom plate provided at the opening of the housing main body part 11 and is provided to cover the opening of the housing main body part 11. In one example, the housing 10 is a hollow rectangular parallelepiped. The orifice 12 has an intake port 121 that draws in air from inside the bathroom 50, and a circulation outlet port 122 that blows air into the bathroom 50. In one example, the housing 10 has a ventilation connection port 111 at a position corresponding to the circulation outlet port 122 on the surface opposite the orifice 12. The circulation outlet port 122 corresponds to the outlet port, and the ventilation connection port 111 corresponds to an exhaust port that exhausts the air drawn in from the intake port 121 to the outside.

The ventilation duct connection part 13 is provided so as to cover the ventilation connection port 111 of the housing main body part 11 from the outside. The ventilation duct connection part 13 is connected to a ventilation duct (not shown) that exhausts the air inside the bathroom 50 to the outside. The ventilation duct connection part 13 has a ventilation exhaust port 131 at the part connected to the ventilation duct.

The bathroom dryer 1 is provided with a damper 14 for switching air paths inside the housing 10, and a stepping motor (not shown) for driving the damper 14. The damper 14 is provided at a position inside the housing 10 where the ventilation air path 101 and the circulation air path 102 branch off. The ventilation air path 101 is an air path that flows the air taken into the housing 10 to the ventilation duct connection part 13, and is an air path that connects the intake port 121 and the ventilation connection port 111. The circulation air path 102 is an air path that flows the air taken into the housing 10 to the bathroom 50, and is an air path that connects the intake port 121 and the circulation outlet 122.

In the example shown in FIG. 1, the damper 14 is located below the ventilation connection port 111 inside the housing 10, and is formed into a plate shape with flat tip and base ends and a curved middle portion. The damper 14 rotates around a damper rotation shaft 141 provided at the base end. The bathroom dryer 1 is equipped with a damper drive mechanism that includes a stepping motor that rotates the damper 14 around the damper rotation shaft 141. The damper drive mechanism is an example of a drive-related component.

Figure 2 is a schematic diagram showing an example of the configuration of a damper drive mechanism in a bathroom dryer. The damper drive mechanism 30 has a sector gear 31, a pinion gear 32, and a stepping motor 33. The sector gear 31 and the pinion gear 32 are combined to form a reducer, or gear, that drives the damper 14.

The sector gear 31 is fixed to the damper rotating shaft 141 at the sector pivot point. The sector gear 31 is also fixed to the base end of the damper 14 at its sector surface. The pinion gear 32 is arranged to mesh with the teeth of the sector gear 31. The stepping motor 33 is a driving means for rotating the pinion gear 32 around the center of the pinion gear 32 as an axis. In other words, the pinion gear 32 is connected to a rotating shaft that is the output shaft of the stepping motor 33, and can be rotated by the stepping motor 33.

By driving the stepping motor 33, the small gear 32 fixed to the rotation shaft of the stepping motor 33 rotates, and the sector gear 31 rotates around the damper rotation shaft 141 in response to the rotation of the small gear 32. Since the damper 14 is fixed to the sector gear 31 and the damper rotation shaft 141, the damper 14 rotates around the damper rotation shaft 141 in response to the rotation of the sector gear 31. In other words, the rotation is transmitted from the small gear 32 attached to the rotation shaft of the stepping motor 33 to the sector gear 31 attached to the damper rotation shaft 141, driving the damper 14.

The degree of opening of the ventilation air passage 101 and the circulation air passage 102 is adjusted by rotating the damper 14. Note that in the first embodiment, as described below, in order to position the stepping motor 33, i.e., to determine the reference position, the damper 14 is rotated and abutted against the inside of the housing 10. After this, the power supply to the stepping motor 33 is temporarily stopped, and the stress on the parts related to the stepping motor 33 and the damper 14 is released, and then excitation is performed.

Returning to FIG. 1, bathroom dryer 1 has blower 15, motor 16, heater 17, filter 18, design panel 19, and control unit 20. Blower 15 is provided inside housing 10. Blower 15 takes in air from bathroom 50 through suction port 121 into housing 10, generating air flow inside housing 10. In one example, blower 15 is a single-suction sirocco fan. In the example of FIG. 1, blower 15 is disposed upstream of ventilation air duct 101 and circulation air duct 102 so as to face suction port 121. Motor 16 drives blower 15. In the example of FIG. 1, motor 16 is disposed outside housing 10.

The heater 17 is a heating unit that heats the air taken into the housing 10. The heater 17 is disposed near the circulation outlet 122. The heater 17 may be capable of switching the heating intensity. In one example, the heater 17 is an electric heater 17.

The filter 18 is positioned upstream of the intake port 121. The filter 18 removes dust and other particles from the air. The decorative panel 19 covers the surface of the housing 10 facing the bathroom 50. In other words, the decorative panel 19 covers the part of the housing 10 exposed to the bathroom 50. The decorative panel 19 is formed flat and is attached with a gap between the ceiling surface and the outer upward side wall of the decorative panel 19, and air from the bathroom 50 is sucked in through the gap around the entire circumference of the decorative panel 19. An opening, the blowing section 191, is provided at a position corresponding to the circulation blowing port 122 of the decorative panel 19. Air that has passed through the circulation air duct 102 is blown out from the blowing section 191 into the bathroom 50.

The control unit 20 controls the bathroom dryer 1. Specifically, the control unit 20 has a memory element in which a predetermined control program is stored, and in response to operation commands input from a remote controller (not shown), it controls the blower 15, heater 17, and damper 14 individually, causing the bathroom dryer 1 to perform heating operation, ventilation operation, drying operation, etc.

Bathroom dryer 1 drives blower 15 to take air from bathroom 50 into housing 10. In heating operation, bathroom dryer 1 blows air that has passed through circulating air duct 102 and has been heated by heater 17 into bathroom 50. In ventilation operation, bathroom dryer 1 sends air from ventilation air duct 101 to ventilation duct connection 13. In drying operation, bathroom dryer 1 sends air that has been taken into housing 10 from ventilation air duct 101 to ventilation duct connection 13, and blows air that has passed through circulating air duct 102 and has been heated by heater 17 into bathroom 50. In drying operation, bathroom dryer 1 may blow cool air into bathroom 50 instead of warm air. Switching between heating operation, ventilation operation, and drying operation is performed by the position of damper 14.

The control unit 20 switches between heating operation, ventilation operation, and drying operation by controlling the blower 15, the damper 14, and the heater 17. In the first embodiment, when the circulation air passage 102 or the ventilation air passage 101 is blocked, the control unit 20 rotates the damper 14 to abut the damper 14 against the inside of the housing 10, and after the abutment occurs, it cuts off the power to the stepping motor 33 and releases the stepping motor 33 from holding the rotating shaft, and then it again energizes the stepping motor 33 and holds the rotating shaft so that it does not rotate due to an external force.

Figure 3 is a diagram showing an example of the rotation principle of a stepping motor. Figure 3 shows a wiring diagram of coils 332 arranged around a rotor 331 of a stepping motor 33. The stepping motor 33 has a rotor 331 and coils 332 wound around a stator (not shown). A base pin 333 is connected to each coil 332. A pin number that identifies the base pin 333 is assigned to the base pin 333.

Figure 4 is a diagram showing an example of the energization sequence of the coils in the stepping motor of Figure 3. Here, the energization sequence, i.e., the excitation sequence, when rotating the stepping motor 33 counterclockwise as viewed from the direction of the rotation axis with 1-2 phase excitation is shown. In this figure, "+" indicates that a positive voltage is applied to the base pin 333, and "-" indicates that a negative voltage is applied to the base pin 333. By applying voltage to the base pin 333 in order from step "1" to "8", the rotor 331 rotates counterclockwise. In this way, the rotating shaft is rotated by changing the coil 332 to be energized for each step. In other words, it is possible to rotate one step at a time by switching the coil 332 to be excited. If you want to stop the rotation and hold it in place, you can continue excitation without proceeding to the next step.

Conventionally, when the stepping motor 33 is driven in this manner and the damper 14 hits the shaft as the shaft rotates, the coil 332 is kept energized to maintain the hit state. This causes stress to be applied to the damper 14, the gears (the sector gear 31 and the pinion 32), and the shaft of the stepping motor 33.

However, in the first embodiment, when a collision occurs, the control unit 20 temporarily stops the supply of electricity to the stepping motor 33. This releases the rotating shaft of the stepping motor 33, and the rotating shaft is not held. In this state, the elastic deformation stress of the damper 14 causes the rotating shaft to rotate in the opposite direction, reducing the stress on the rotating shaft and gears. After that, the stepping motor 33 is energized to excite it and hold the rotating shaft. This makes it possible to reduce the stress on each part compared to when a collision occurs.

Next, the ventilation, heating, and drying operations of the bathroom dryer 1 of the first embodiment will be described. FIG. 5 is a diagram showing an example of the state of the air duct during ventilation operation of the bathroom dryer. The white arrows in FIG. 5 represent the flow of air. The same applies to the following figures. In ventilation operation, the damper 14 is arranged to prevent air from the bathroom 50 from going to the blowing section 191 via the heater 17 and to flow to the ventilation connection port 111, forming the ventilation air duct 101. That is, the damper 14 fully closes the circulation air duct 102 and is in a state where it abuts against a member inside the housing 10. In this example, the tip of the damper 14 is in a state where it abuts against the orifice 12. As a result, the ventilation air duct 101 is formed inside the housing 10. In addition, the reference position is detected by abutting the damper 14 against the orifice 12. When the blower 15 starts operating, the air in the bathroom 50 flows from the intake port 121 through the ventilation air duct 101. That is, the air in the bathroom 50 is guided by the damper 14 to the ventilation connection port 111 and exhausted to the outdoors via the ventilation duct connection part 13.

In the bathroom dryer 1, when switching from heating operation to ventilation operation, from drying operation to ventilation operation, and from stopped to ventilation operation, the damper 14 performs the abutting operation as described above. To block the circulation outlet 122, the damper 14 performs the abutting operation with its tip in contact with the orifice 12. After that, the power supply to the stepping motor 33 is temporarily stopped to release the stress, and then the power supply is turned on again to excite it. This makes it possible to block the circulation outlet 122 in a state where the stress on the rotating shaft and gear of the stepping motor 33 is weaker than the stress applied during the abutting operation.

Figure 6 is a diagram showing an example of the state of the air passage during heating operation of the bathroom dryer. In heating operation, the ventilation connection port 111 is closed, and the damper 14 is arranged so that the air from the bathroom 50 flows through the heater 17 to the blowing section 191, forming the circulation air passage 102. That is, the damper 14 is in a fully open state that blocks the ventilation air passage 101, and is in a state where it hits a member inside the housing 10. In this example, the tip of the damper 14 is in a state where it hits the upper surface of the housing 10. As a result, the circulation air passage 102 is formed inside the housing 10. In addition, the reference position is detected by hitting the upper surface of the housing 10. Then, a heating operation is possible in which the air taken in from the bathroom 50 is heated by the heater 17 and returned to the bathroom 50. During heating operation, the blower 15 is driven to take the air from the bathroom 50 into the housing 10. The air taken into the housing 10 by the blower 15 passes through the circulation air passage 102, is heated by the heater 17, and is then blown out of the circulation outlet 122 through the blowing section 191 into the bathroom 50.

In the bathroom dryer 1, when switching from ventilation to heating, from drying to heating, and from stopped to heating, the damper 14 performs the abutting operation as described above. To close the ventilation connection port 111, the damper 14 performs the abutting operation with its tip in contact with the top surface of the housing 10. After that, the power to the stepping motor 33 is temporarily stopped to release the stress, and then the power is turned on again to excite it. This makes it possible to block the circulation outlet 122 in a state where the stress on the rotating shaft and gear of the stepping motor 33 is weaker than the stress applied during the abutting operation.

Figure 7 is a diagram showing an example of the state of the air passage during the drying operation of the bathroom dryer. In the drying operation, the damper 14 is arranged to form a circulation air passage 102 in which part of the air taken in from the bathroom 50 is heated by the heater 17 and returned to the bathroom 50 from the blowing section 191, and a ventilation air passage 101 in which the remaining air is exhausted to the outside from the ventilation connection port 111. In other words, the damper 14 is held in a position between the orifice 12 and the upper surface of the housing 10. This splits the air flow into two, and the circulation air passage 102 that flows toward the heater 17 and the ventilation air passage 101 that flows toward the ventilation connection port 111 are secured inside the housing 10. In the drying operation, ventilation is performed while blowing out warm air into the bathroom 50, and the bathroom 50 or clothes can be dried, and the bathroom dryer 1 can function as a warm air dryer.

During drying operation, the damper 14 does not come into contact with either the orifice 12 or the upper surface of the housing 10. In other words, the damper 14 does not perform abutting operations, so it can be excited immediately after being driven by the stepping motor 33.

Next, the control method of the ventilation fan according to the first embodiment will be described in detail. FIG. 8 is a flowchart showing an example of the procedure of the control method of the ventilation fan according to the first embodiment. FIG. 9 is a diagram showing an example of the order of energizing the coils of the stepping motor in the control method of the ventilation fan according to the first embodiment. Here, an example is taken of switching from a fully closed state in which the circulating air passage 102 to the inside of the bathroom 50 in FIG. 5 is closed to a fully open state in which the circulating air passage 102 to the inside of the bathroom 50 in FIG. 6 is open, that is, switching from ventilation operation to heating operation. Note that when the control method of the ventilation fan shown in FIG. 8 is being executed, the fan 15 is assumed to remain in operation.

First, the control unit 20 of the ventilation blower drives the stepping motor 33 to perform the butting process (step S1). In the determined energization sequence shown in FIG. 9, a voltage is applied to the base pin 333 to excite the coil 332, causing the rotor 331 to rotate, and a forward rotation step is performed in which the damper 14 is rotated clockwise as viewed from the output shaft direction via a gear connected to the rotation shaft of the rotor 331, i.e., the rotation shaft of the stepping motor 33. In one example, the clockwise forward rotation steps shown in steps "1" to "8" are performed several dozen times. This causes the rotation shaft of the stepping motor 33 to rotate, and the damper 14 connected to the rotation shaft via a gear rotates clockwise from the state in FIG. 5 to the state in FIG. 6. From the fully closed state of the circulation air passage 102 in FIG. 5 to the fully open state of the circulation air passage 102 in FIG. 6, the opening and closing angle of the damper 14 is rotated, for example, by 30°.

In the impact process of step S1, a voltage is applied to each base pin 333 in a forward rotation step so that the damper 14 rotates forward by about 10 to 20 percent more than the opening and closing angle, and the damper 14 is impacted against the top surface of the housing 10. When the damper 14 impacts the top surface of the housing 10, the damper 14 deforms slightly and adheres to the top surface of the housing 10, thereby blocking the ventilation connection port 111 of the upper ventilation air passage 101. At this time, stress corresponding to the elastic deformation of the damper 14 is generated in the rotating shaft and gear.

Next, the control unit 20 performs a rotating shaft releasing process in which the voltage application to the base pins 333 is cut off to release the rotating shaft of the stepping motor 33 (step S2). At this time, the rotating shaft rotates in the opposite direction due to the stress corresponding to the elastic deformation of the damper 14, and the stress on the rotating shaft and gears is reduced. As shown in FIG. 9, no voltage is applied to any of the base pins 333.

Then, the control unit 20 performs a holding step in which a voltage is applied to the determined position of the base pin 333 (step S3). In one example, as shown in FIG. 9, the coil 332 corresponding to the state of "1" in the forward rotation step is excited, and the rotation shaft is held at the position of "1" in the forward rotation step. This completes the control method for the ventilation blower.

Figure 10 is a diagram showing an example of the state of stress on the rotating shaft and gears at each step of the ventilation fan control method according to embodiment 1. In this diagram, the horizontal axis shows time, and the vertical axis shows stress on the rotating shaft and gears. Here, for ease of understanding, the horizontal axis also shows the steps in Figures 8 and 9.

Time T1-1 corresponds to the rotational position of the damper 14 when the circulating air passage 102 in Figure 5 is in a fully closed state. In the abutment process of step S1, the rotation shaft of the damper 14 is rotated in the forward direction, i.e., clockwise from the state in Figure 5 to the state in Figure 6. As a result, at time T1-2, the damper 14 is in a slightly floating state. In this state, rotational stress due to the damper 14's own weight acts on the rotating shaft and gear. Until time T1-3, rotational stress due to the damper 14's own weight acts on the rotating shaft and gear.

When the rotation shaft of the damper 14 is further rotated in the forward direction, the circulating air passage 102 in FIG. 6 is fully opened. That is, at time T1-3, the damper 14 abuts against the upper surface of the housing 10, blocking the ventilation connection port 111 and fully opening the circulating air passage 102.

When the rotation shaft of the damper 14 is rotated in the forward direction from the state where the damper 14 is abutted against the upper surface of the housing 10, the damper rotation shaft 141 rotates while the damper 14 elastically deforms. At this time, the rotation shaft of the stepping motor 33 is subjected to a stress that is the sum of the rotational stress due to the weight of the damper 14 and the stress due to the elastic deformation of the damper 14.

When the damper rotating shaft 141 is further rotated in the forward direction and the stress on the rotating shaft increases, slippage occurs between the stator and rotor 331 of the stepping motor 33. Therefore, no greater stress acts on the rotating shaft. The state in which the rotational stress of the rotating shaft is balanced with the slip torque of the stepping motor 33 is time T1-4, and the stress at this time is St-14. If a rotation command is issued to the stepping motor 33 beyond this point, slippage will occur and the stress will not increase. In other words, the stress remains constant until time T2-1, which is the end of the abutment process in step S1.

Next, in the rotating shaft releasing process of step S2, at time T2-1, the voltage applied to the base pin 333 is cut off to release the rotating shaft. At this time, the rotating shaft rotates in the reverse direction due to the elastic deformation stress of the damper 14, and the stress on the rotating shaft and gear decreases. That is, in response to the reverse rotation of the rotating shaft, the stress decreases from St-14 to St-22 between time T2-1 and time T2-2.

The gear of the rotating shaft has a frictional force against rotation, and even when the rotating shaft is in the released state, the stress does not become completely zero, and the rotating shaft is held in a constant stress state. This state continues from time T2-2 until time T3-1, when the holding process of step S3 begins.

After that, in the holding process of step S3, at time T3-1, a voltage is applied to the base pin 333, which corresponds to the state of forward rotation step "1" in FIG. 9. This holds the rotating shaft at the position of forward rotation step "1". At this time, the rotating shaft and gear are held in the stress state at time T3-1, i.e., in a state in which stress St-22 is applied. In other words, when the damper 14 is in a fully open state blocking the ventilation air duct 101 or in a fully closed state blocking the circulation air duct 102, the rotating shaft of the stepping motor 33 is in a state in which a stress equal to the frictional force of the rotating shaft is applied. This ends the process.

In this way, in the first embodiment, the voltage applied to the coil 332 is cut off after the impact, and the rotating shaft is released. As a result, the elastic deformation stress of the damper 14 rotates the rotating shaft in the opposite direction to the rotation direction at the time of impact. In other words, since the rotating shaft is not held and can rotate, the elastic deformation stress of the damper 14 is released by the rotation of the rotating shaft in the opposite direction. As a result, as shown in FIG. 10, the stress on the rotating shaft can be reduced from St-14 to St-22. In other words, it can be reduced to the same stress as the friction force against the rotation of the gear of the rotating shaft. After that, a voltage is applied to the coil 332 to excite it, and the rotating shaft is held at a determined position. As a result, the stress due to the impact operation when the reference position is determined is alleviated, and the stress on the rotating shaft and the gear can be reduced compared to the conventional ventilation blower in which the rotating shaft is held in the state of the stepping motor 33 where the impact occurs in the damper 14. This reduces the deterioration of the driving parts of the stepping motor 33 and the damper 14, and the life of the ventilation blower can be extended.

Embodiment 2.
The configuration of the ventilation fan according to the second embodiment is similar to that described in the first embodiment. However, the process performed by the control unit 20 after the damper 14 hits the wall is different. The differences from the first embodiment are described below.

The control unit 20 of the ventilation blower according to the second embodiment cuts off the voltage application to the base pin 333 after the abutting operation, releases the rotating shaft, and then rotates the stepping motor 33 in the reverse direction by several pulses. In other words, it actively reduces the stress on the stepping motor 33 and the drive-related components of the damper 14. The control unit 20 then applies a voltage to the base pin 333 at a position that will result in a specified state, thereby exciting it. The reverse rotation is performed in the opposite direction to the rotation direction in which the abutting operation is performed, by several rotations.

Next, the control method of the ventilation fan according to the second embodiment will be described in detail. FIG. 11 is a flowchart showing an example of the procedure of the control method of the ventilation fan according to the second embodiment. FIG. 12 is a diagram showing an example of the order of energization of the coil of the stepping motor in the control method of the ventilation fan according to the second embodiment. Here, an example is given of an operation from a fully closed state in which the circulating air passage 102 to the inside of the bathroom 50 in FIG. 5 is closed to a fully open state in which the circulating air passage 102 to the inside of the bathroom 50 in FIG. 6 is opened, that is, a case of switching from ventilation operation to heating operation. Note that, below, the same process as in FIG. 8 of the first embodiment is assigned the same step number, and different parts are described. Also, when the control method of the ventilation fan shown in FIG. 11 is being executed, the blower 15 remains in operation.

As in FIG. 8 of the first embodiment, the control unit 20 of the ventilation blower performs the butting process of step S1 and the rotating shaft opening process of step S2. As in the first embodiment, in the predetermined energization sequence shown in FIG. 12, a voltage is applied to the base pin 333 to excite the coil 332, causing the rotor 331 to rotate, and a forward rotation step is performed several dozen times to rotate the damper 14 in the clockwise direction of the rotating shaft of the rotor 331 as viewed from the rotating shaft direction. After that, as shown in FIG. 12, all the base pins 333 are in an open state with no voltage applied.

Then, the control unit 20 performs a reverse rotation step to rotate the rotating shaft in the reverse direction (step S11). At this time, by rotating the rotating shaft further back than the holding state with the same stress as the frictional force against the rotation of the gear of the rotating shaft, the stress on the rotating shaft and the gear is reduced compared to the rotating shaft release step of step S2. In the predetermined excitation order shown in the reverse rotation step of FIG. 12, a voltage is applied to the base pin 333 to excite the coil 332, causing the rotor 331 to rotate, and a reverse rotation step is performed in which the rotating shaft of the rotor 331 rotates the damper 14 counterclockwise as viewed from the output shaft direction. In one example, the counterclockwise reverse rotation step shown in steps "8" to "1" is executed several times. This causes the stepping motor 33 to rotate in the reverse direction.

In one example, if the rotation axis of the damper 14 is horizontal and a collision occurs below in the vertical direction, even if the rotation axis releasing process is performed, the damper 14 cannot rotate in a direction against gravity, so the stress on the rotation axis and gears may not be reduced much. Also, if the rotation axis of the damper 14 is vertical, it is difficult to release the stress for the same reason. In such a case, it is possible to reduce the stress on the rotation axis and gears by rotating the rotation axis in the opposite direction.

Then, the holding process of step S3 is executed. In one example, as shown in FIG. 12, coil 332 is excited and the rotating shaft is held at the position of forward rotation step "1". This completes the control method for the ventilation blower.

Figure 13 is a diagram showing an example of the state of stress on the rotating shaft and gears at each step of the control method for the ventilation blower according to embodiment 2. In this diagram, the horizontal axis indicates time, and the vertical axis indicates stress on the rotating shaft and gears. Here, for ease of explanation, the horizontal axis also indicates the steps in Figures 11 and 12. Note that a description of the same parts as in Figure 10 of embodiment 1 will be omitted, and the different parts will be described.

In the second embodiment, in the reverse rotation step of step S11 following the rotating shaft releasing step of step S2, the rotating shaft is rotated in reverse at time T11-1. At this time, by rotating the rotating shaft back further than the state in which the same stress as the frictional force against the rotation of the gear of the rotating shaft is maintained, the stress on the rotating shaft and the gear is reduced compared to the rotating shaft releasing step of step S2. That is, in response to the reverse rotation of the rotating shaft, the stress is reduced from St-22 to St-112 between time T11-1 and time T3-1.

After that, in the holding process of step S3 at time T3-1, the control unit 20 applies a voltage to the base pin 333, which corresponds to the state of forward rotation step "1" in FIG. 12. This holds the rotating shaft at the position of forward rotation step "1". At this time, the rotating shaft and gear are held in the state of time T3-1, that is, in a state in which stress St-112 is applied. In other words, when the damper 14 is in a fully open state blocking the ventilation air duct 101 or in a fully closed state blocking the circulation air duct 102, the rotating shaft of the stepping motor 33 is in a state in which a stress smaller than the frictional force of the rotating shaft is applied. This ends the process.

In this way, in the second embodiment, after the impact, the voltage applied to the coil 332 is turned off, the rotating shaft is released, and then rotated in the reverse direction. This makes it possible to reduce the stress on the rotating shaft from St-14 to St-112, as shown in FIG. 13. In other words, it is possible to reduce the stress on the rotating shaft and gear to a stress that is smaller than the frictional force against the rotation of the gear of the rotating shaft. The second embodiment is particularly effective in an environment where the impact occurs in a direction where it is difficult to release the stress, such as when the rotating shaft of the damper 14 is horizontal and the impact occurs below in the vertical direction, or when the rotating shaft of the damper 14 is vertical.

Embodiment 3
In the third embodiment, a ventilation fan that combines the first and second embodiments will be described. The configuration of the ventilation fan according to the third embodiment is similar to that described in the first and second embodiments. However, the process performed by the control unit 20 after the damper 14 hits the wall is different. The following describes the differences from the first and second embodiments.

Take the case where the drive shaft of the damper 14 is horizontal and the upper and lower sides are butted in the vertical direction as an example. In the case of rotation of the damper 14 accompanied by the upper butted operation in the vertical direction, the control unit 20 of the ventilation blower performs control according to the procedure shown in FIG. 8 of the first embodiment. That is, the control unit 20 performs a butting process in which the upper side is butted, a rotating shaft release process in which the power supply to the stepping motor 33 is temporarily stopped, and a holding process in which the rotating shaft is held by excitation in succession. On the other hand, in the case of rotation of the damper 14 accompanied by the lower side butted operation in the vertical direction, the control unit 20 performs control according to the procedure shown in FIG. 11 of the second embodiment. That is, the control unit 20 performs a butting process in which the lower side is butted, a rotating shaft release process in which the power supply to the stepping motor 33 is temporarily stopped, a reverse rotation process in which the motor is rotated in the reverse direction by several pulses, and a holding process in which the motor is excited and the rotating shaft is held in succession. In one example, the reverse rotation is performed several times, with step "8" to step "1" in the reverse rotation steps of FIG. 12 being one rotation. When striking from above, the weight of the damper 14 is utilized, and when striking from below, the stepping motor 33 is rotated in the reverse direction to reduce stress on the rotating shaft and gears.

When the shaft strikes the upper side, the rotation direction at the time of striking is opposite to the rotation direction due to the weight of the damper 14, so the stress is relieved by the rotating shaft releasing process. On the other hand, when the shaft strikes the lower side, the rotation direction at the time of striking is the same as the rotation direction due to the weight of the damper 14, so the stress is added. In other words, even if the rotating shaft releasing process is performed, the stress is less likely to be relieved compared to when the shaft strikes the upper side. For this reason, it is desirable to relieve the stress by rotating the stepping motor 33 in the opposite direction.

When installing the ventilation blower, the installer can ascertain whether the rotation axis of the damper 14 is horizontal or not, and if the rotation axis is horizontal, whether the position where the damper 14 hits is on the upper or lower vertical side. The installer sets the control unit 20 to make the stepping motor 33 perform the process described in embodiment 1 when the rotation axis of the damper 14 is horizontal and the position where the damper 14 hits is on the upper vertical side, and to make the stepping motor 33 perform the process described in embodiment 2 when the position where the damper 14 hits is on the lower vertical side.

Effects similar to those of embodiments 1 and 2 can be obtained with embodiment 3 as well.

Embodiment 4.
The configuration of the ventilation fan according to the fourth embodiment is similar to that described in the first to third embodiments. The following describes the differences from the first to third embodiments. In the ventilation fan according to the fourth embodiment, when controlling the abutting operation of the damper 14, the control unit 20 stops the operation of the blower 15 when the damper 14 is driven. That is, the control unit 20 stops the driving of the blower 15 before driving the damper 14, causes the damper 14 to rotate, and then drives the blower 15.

Next, the control method for the ventilation fan according to the fourth embodiment will be described in detail. Figure 14 is a flow chart showing an example of the procedure for the control method for the ventilation fan according to the fourth embodiment. Note that, as in the second embodiment, an example is shown here in which the reverse rotation process is performed after the rotating shaft opening process. Below, the same steps as those in Figure 8 of the first embodiment and Figure 11 of the second embodiment are given the same step numbers, and differences will be described.

First, the control unit 20 of the ventilation blower executes a blower stop process to stop the blowing of air by the blower 15 (step S21). If the damper 14 is operated while the blower 15 is running, the pressure from the blowing air will also act on the rotating shaft. In addition, the blowing pressure will change due to pressure loss, etc., and become unstable. Therefore, in the fourth embodiment, the blower 15 is stopped before the damper 14 is rotated. As a result, the abutting operation is performed with the blower 15 turned off, and stable stress relaxation can be performed regardless of the blowing of air by the blower 15.

Then, the control unit 20 performs the steps from the butting step S1 to the holding step S3 described in the first and second embodiments. After the holding step S3, the control unit 20 performs the blower operation step of operating the blower 15 (step S22). This completes the process.

In embodiment 4, before the rotation of damper 14 with the abutting operation, the rotation of damper 14 with the abutting operation described in embodiments 1 to 3 is performed with blower 15 stopped, and then blower 15 is operated. This makes it possible to suppress the pressure caused by the air blowing from acting on the rotating shaft via damper 14 during the abutting operation. It is also possible to suppress the effect on the rotating shaft of the unstable air blowing pressure that changes due to pressure loss, etc. As a result, it has the effect of being able to perform stable stress relaxation regardless of the air blown by blower 15.

The control unit 20 described in the first to fourth embodiments is realized as a processing circuit. The processing circuit may be dedicated hardware, an integrated circuit, or a circuit including a processor. FIG. 15 is a block diagram showing an example of the hardware configuration of the control unit provided in the ventilation blower according to the first to fourth embodiments. The control unit 20 includes a processor 501 and a memory 502. The processor 501 is a CPU (also called a Central Processing Unit, central processing unit, processing unit, arithmetic unit, microprocessor, microcomputer, DSP (Digital Signal Processor)), a system LSI (Large Scale Integration), or the like. The memory 502 is a non-volatile or volatile semiconductor memory such as a RAM (Random Access Memory), a ROM (Read Only Memory), a flash memory, an EPROM (Erasable Programmable Read Only Memory), an EEPROM (registered trademark) (Electrically Erasable Programmable Read-Only Memory), a magnetic disk, a flexible disk, an optical disk, a compact disk, a mini disk, or a DVD (Digital Versatile Disc), etc. The processor 501 and the memory 502 are connected via a bus line 503.

The functions of the control unit 20 are realized by reading from the memory 502 a program describing the procedure for the method of controlling the ventilation blower, including the process of controlling the switching of the damper 14, and executing it by the processor 501. In addition, multiple processors and multiple memories may work together to realize the above functions. In addition, some of the functions of the control unit 20 may be implemented as an electronic circuit, which is dedicated hardware, and other parts may be realized using the processor 501 and the memory 502. In one example, the control unit 20 controls the operation of the blower 15 and the damper drive unit using electrical signals.

The configurations shown in the above embodiments are merely examples, and may be combined with other known technologies, or the embodiments may be combined with each other. In addition, parts of the configurations may be omitted or modified without departing from the spirit of the invention.

1 bathroom dryer, 10 housing, 11 housing main body, 12 orifice, 13 ventilation duct connection, 14 damper, 15 blower, 16 motor, 17 heater, 18 filter, 19 design panel, 20 control unit, 30 damper drive mechanism, 31 sector gear, 32 pinion, 33 stepping motor, 50 bathroom, 51 ceiling, 52 ceiling space, 101 ventilation air duct, 102 circulation air duct, 111 ventilation connection port, 121 intake port, 122 circulation air outlet, 131 ventilation exhaust port, 141 damper rotating shaft, 191 air outlet, 331 rotor, 332 coil, 333 base pin.

Claims (5)

A control method for a ventilation fan including a housing having an intake port for sucking in indoor air, an exhaust port for blowing air into the room, and an exhaust port for exhausting the air sucked from the intake port to the outside, a damper that switches between a circulation air passage connecting the intake port and the exhaust port and a ventilation air passage connecting the intake port and the exhaust port by rotating about a rotation shaft, a stepping motor connected to the rotation shaft for driving the damper, and a fan provided inside the housing, comprising:
abutting step of driving the stepping motor to abut the damper against an inside of the housing so that the damper is in a fully open state in which the damper blocks the ventilation air passage or in a fully closed state in which the damper blocks the circulation air passage;
a rotating shaft releasing step of cutting off the power supply to the stepping motor to release the state in which the rotating shaft is held;
a holding step of energizing the stepping motor to excite it and hold the rotating shaft;
Including,
a control method for a ventilation fan, comprising the steps of: successively carrying out the abutting step, the rotating shaft releasing step, and the holding step when the damper is abutted against an inside of the housing . The method further includes a reverse rotation step of rotating the rotating shaft in a direction opposite to the direction of rotation in the abutting step after the rotating shaft releasing step and before the holding step,
2. The method for controlling a ventilation fan according to claim 1 , wherein the abutting step, the rotating shaft releasing step, the reverse rotation step, and the holding step are carried out consecutively when the damper is abutted against the inside of the housing . When the rotation shaft is disposed in a horizontal direction and strikes against the inside of the housing at an upper side in a vertical direction in either the fully open state or the fully closed state, the striking step, the rotation shaft releasing step, and the holding step are carried out successively;
3. The control method for a ventilation fan according to claim 2, wherein when the rotating shaft strikes the inside of the housing at a vertically lower side in the other of the fully open state and the fully closed state, the striking step, the rotating shaft releasing step, the reverse rotation step, and the holding step are carried out successively. The method for controlling a ventilation fan according to claim 2, characterized in that the reverse rotation process is performed when the rotation shaft is arranged vertically. The method for controlling a ventilation fan according to any one of claims 1 to 4, further comprising a blower stopping step for stopping the blowing of air by the blower before the impacting step.

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