JPH1146934A - Air supply device for air mat - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an air supply device of air pump which can significantly reduce the frequency of start and stop of the air pump by controlling the air pressure in an air mat so as to keep a specified value. SOLUTION: This air supply device is provided with an air mat formed so that the first air cell group and the second air cell group are alternately arranged which are made of multiple tube air cells, and an air switching valve 6 which switches air supply and discharge so that air is supplied to the first and second air cell groups alternately at specified interval times at a pressure set by a pressure measuring device 9 and air is discharged from the first and second air cell groups alternately at specified interval times into the air. A control circuit 13 is also provided which operates an air pump 2 strongly when a pressure in the first and second air cell groups is lower than a specified value, and operates the air pump 2 weakly so that the air pump 2 supplies air by an amount less than that leaked at the first and second air cell groups and ducts connected to them when a pressure in the first and second air cell groups is higher than a specified value.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an air supply device for an air mat which controls pressure so that a comfortable sleep can be obtained.

[0002]

2. Description of the Related Art An air mat used in conventional bedding is provided with an internal pressure which is adjusted so that a bedridden elderly person or sick person does not suffer from bedsore, and a healthy person can get a comfortable sleep. I have.

As an air mat having a control means for controlling the pressure of the air mat, for example, Japanese Utility Model Registration No. 2
No. 524410 is known. The conventional air mat includes a plurality of first and second air cells alternately arranged in the longitudinal direction of the mat body, a first system pipe connecting to the first system air cells, and a second system conduit. The air of the adjusted pressure is switched and supplied at predetermined intervals through a second pipeline connected to each of the air cells, and the first pipeline and the second pipeline are released to the atmosphere at predetermined intervals. An air supply device that is in communication with the air supply device, wherein a switching valve that switches the supply of air to the first system pipeline and the second system pipeline is provided inside the air supply device. A sensor for detecting pressure, a setting device for setting a predetermined value of the pressure,
An air pump for supplying air supplied to the first system pipeline and the second system pipeline to the switching valve, and a controller for controlling the switching valve and the air pump are provided.

[0004]

However, in the above-mentioned conventional air mat, when the sensor detects that the pressures in the first system line and the second system line have become lower than the set values, the air pump starts operating. Since the operation of the air pump is stopped when the pressure in the pipe exceeds the set value, the operation and stop of the air pump are frequently performed. As a result, the following problems occur.

[0005] (1) Normally, an air pump generates a considerable amount of noise during operation, but almost no noise when stopped. For this reason, when the frequency of driving and stopping becomes high, noise during driving is heard more loudly than necessary, which causes trouble in sleep. (2) Most air pumps use electromagnetic solenoids or electric motors, which generate inrush current at the start of operation and electrical noise such as voltage spikes at the start of operation. If it is high, high-density electrical noise is generated, which adversely affects electrical devices connected to the same power supply, particularly medical instruments. (3) The rush current generated when the air pump is started causes a stress on the switching element that controls the operation and stop of the air pump. Therefore, if the frequency of the operation and stop is high, the life of the switching element is shortened early.

In order to improve such a problem, an air supply device has been proposed in which the operation of the air pump is delayed for a while even when the pressure in the air mat becomes lower than a set value. However, in this method, if the pressure in the air mat decreases rapidly, the pressure in the air mat receiving the air supply from the air supply device becomes considerably lower than the set value, and the set value becomes unreliable. is there.

[0007] Further, since the pressure fluctuation in the air mat becomes large, sleep is hindered, and if the air supply is slow,
There is also a problem that the user bottoms out and gives the user discomfort. The present invention has been made in order to improve such a conventional problem. By controlling the pressure in the air mat to a pressure close to a set value, the frequency of the operation and the stop of the air pump is greatly reduced. It is an object to provide an air supply device.

[0008]

According to the first aspect of the present invention, a first system air cell group and a second system air cell group comprising a plurality of tubular air cells are alternately arranged. The air mat and the air having the pressure set in advance by the pressure measuring device are switched at predetermined time intervals and supplied to the first and second air cell groups, respectively, and the first and second air cell groups are changed at predetermined time intervals. An air switching valve for switching the supply and discharge of air so as to open to the atmosphere; and an air switching valve provided between the air switching valve and the air pump, and provided in the first air cell group and the second air cell group. A pressure sensor for detecting pressure, and when the pressure in the first and second system air cells detected by the pressure sensor is lower than a preset value, the air pump is strongly operated; When the pressure in the first and second system air cells becomes higher than the set value, air smaller than the amount corresponding to the amount of air leaking from the first and second system air cells and the path leading to the first and second system air cells is supplied from the air pump. It is configured by a control circuit that weakly operates the air pump so as to be supplied.

According to the above configuration, when the pressure sensor detects that the pressure in the first and second system air cells constituting the air mat has become higher than the set value, the air pump is switched to the weak operation and the first and second air cells are switched. Air is supplied to the first and second system air cells according to the amount of air leakage from the two system air cells and the path leading to the two systems air cells, so that the pressure in the first and second systems air cells is maintained at the set pressure. Become so.

When the pressure sensor detects that the pressure in the first and second system air cells has dropped below a set value, the air pump is operated strongly, and air is again supplied to the first and second system air cells. By repeating the above operation, the pressure in the first and second system air cells can be constantly maintained at the set value.

In order to achieve the above object, the invention according to claim 2 is characterized in that when the air pump is weakly operated, the amount of air leakage is 60 to 90%.
The air pump is controlled so that the% air is discharged from the air pump.

According to the above configuration, the frequency of switching between the strong operation and the weak operation of the air pump can be greatly reduced as compared with the conventional one, and the pressure fluctuation in the air mat can be reduced. Can be eliminated.

According to a third aspect of the present invention, a muffler is connected in the middle of an air tube connecting the air pump and the pressure sensor.

According to the above configuration, the pulsation of the air generated by the air pump is smoothed by the silencer, so that the air with less pressure pulsation can be supplied to the air mat.

[0015]

Embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a partially cutaway perspective view of an air mat and an air supply device, and FIGS.

The air mat 1 shown in Figure 1, a flexible place a number of first system air cell group 1 ₁ and the second system air cell group 1 ₂ formed from tubular air cells alternate with, and the surface It has a coated structure woven 1a such as sheets, the first system air cell group 1 ₁ and the second system air cell group 1 ₂ each air supply pipe 3a is in, the one end side of the 3b are connected.

Reference numeral 4 denotes an air supply unit connected to the other end of the air supply pipes 3a and 3b. As shown in FIG. 2, air switching for alternately supplying and discharging air to and from the air supply pipes 3a and 3b is performed. A valve 6, a motor 7 for driving the air switching valve 6, an air pump 2 for supplying air to the air switching valve 6, and a pressure sensor installed in the air tube 12b immediately before the air switching valve 6 5 and a silencer 1 comprising four chambers installed between the pressure sensor 5 and the air pump 2.
1 and a signal processing circuit 8 on which the pressure sensor 5 is mounted
Connected to the signal processing circuit 8 and connected to the first and second
A pressure setting device 9 for setting the internal pressure after the supply air system air cell group 1 _1, 1 ₂ to a predetermined value, controls the drive of the limit switch 10 and the motor 7 and the pump 2 for detecting a switching position of the air control valve 6 The control circuit 13 includes a control circuit 13.

The air discharged from the air pump 2 is
Once supplied to the silencer 11 by the air tube 12a to mute the sound, the air is supplied to the air switching valve 6 via the pressure sensor 5 by the air tube 12b, and the air pump 2 is connected to the power cord 14 by the power cord 14 for commercial household use. The power supply (100V) is connected.

On the other hand, the air switching valve 6, as shown in FIGS. 3 to 5, has a disk-shaped fixed plate 6a and a rotor 6b provided on the fixed plate 6a. Is
The motor 7 is rotatable by a motor 7 attached to the lower surface of the fixed plate 6a, and a compression spring 6c for pressing the rotor 6b against the fixed plate 6a is attached to the tip of the rotating shaft 7a of the motor 7.

As shown in FIG. 4, the fixed plate 6a has
Three-way air passage _{6 1,} 6 2, _{6 3} are formed inside, of these air passages ₆₁ through _3, one end of the air passage _61, connected to the first system air cell group _{1 1} been air supply pipe 3a is also on one end side of the air passage 6 _2, air supply pipe 3b connected to the second system air cell group 1 ₂ are connected. These air passages _{6 and 62} on the other end side, the fixed plate 6
on both sides the upper surface of a central portion in the opened shaft hole 6d, with are respectively open the first outlet 6e and the second discharge port 6f, one end of the air passage 6 _3, air tube 1
The other end is connected to the pressure sensor 5 by an air inlet hole 6g near the shaft hole 6d.
It is opened as.

As shown in FIG. 5, the rotor 6b has a substantially semicircular air supply groove 6 around a shaft hole 6h opened at the center.
i and a fan-shaped distribution groove 6 continuous with the air supply groove 6i.
j is formed, and on the opposite side of the distribution groove 6j, an exhaust hole 6k that is open to the atmosphere by a plurality of small holes is formed, and on the outer peripheral surface, the peripheral portion of the distribution groove 6j and the opposite portion are formed. On the side, a protrusion 6m for operating the limit switch 10,
6n are provided so as to protrude over substantially a quarter of the circumference.

As shown in FIG. 6, the pressure sensor 5 is a T-shaped branch pipe 5 connected in the middle of the air tube 12b.
The pressure sensor element 5c is connected to the branch portion of the branch pipe 5a via an air tube 5b. The pressure sensor element 5c is attached to the signal processing circuit 8 and generates a pressure signal (current) proportional to the air pressure flowing through the air tube 12b. Are input to the positive-phase amplifier 8a of the signal processing circuit 8 shown in FIG.

The signal processing circuit 8 includes a pressure sensor element 5
and a voltage comparator 8b for comparing the pressure signal amplified by the positive-phase amplifier 8a with the set value artificially set by the pressure setting device 9. ing.

The voltage comparator 8b has an appropriate hysteresis. When the pressure signal from the positive-phase amplifier 8a has a hysteresis voltage higher than the set value from the pressure setter 9, the voltage comparator 8b is turned on. It is turned off when the voltage becomes lower than the voltage obtained by subtracting the hysteresis voltage from the set value.When the difference between the two voltages is within the hysteresis voltage, the state immediately before that is maintained. Chattering does not occur.

The output of the voltage comparator 8b is input to a microcomputer 13a of the control circuit 13 as an output signal of the signal processing circuit 8. The control circuit 13 has a microcomputer 13a as shown in FIG.
The output signal from the signal processing circuit 8 and the signal from the limit switch 10 are input to the microcomputer 13a.
The motor 7 and the air pump 2
The air pumps 2 are connected via a power switching circuit 13c for switching the power supplied to the power supply to high or low.

The power switching circuit 13c emits light when a signal H is input to an input terminal 13d as shown in FIG.
A solid-state relay 1 including an ED 13e and a triac 13f that is turned on by the emission of the LED 13e.
3g, and a low-power resistor 13h connected in parallel to both ends of the solid-state relay 13g. An AC power supply is connected to the input side, and the air pump 2 is connected to the output side.

The resistance value of the low power resistor 13h is determined by the first and second air cell groups 11 ₁ and 1 1 of the air mat 1.
₂ and the amount of air leaking from the air switching valve 6 or the like is calculated, and a voltage to be applied to replenish and discharge 60 to 90% of the measured value is obtained. The value is set so as to be applied to the air pump 2 during conduction.

Next, the operation of the air supply device for an air mat constructed as described above will be described with reference to FIGS. The air mattress 1 and bedridden elderly, when used as bedsores mat such as sick, set in the pressure setting device 9 so that the pressure in the first and second line air cell group ₁ 1, ₁ in ₂ is in the range of 250~600mmAq Set the value.

The pressure after exhaust is 1/3 of the pressure after supply.
It is set to a range of 1/2, that is, a range of 80 to 300 mmAq. The reason why the post-exhaust air pressure is set to be equal to or less than の of the post-air supply air pressure is to increase the level difference between the air supply air cell and the exhaust air cell to promote blood circulation in the exhaust air cell portion. Further, the upper limit of the post-evacuation pressure is set to 300 mmAq, because if it exceeds this, the possibility of occurrence of bedsore increases. Further, if it is set lower than 80 mmAq, the force for supporting the patient's body is weakened, the cell may be crushed by the weight, and the bottom may come into contact with the floor, which is not preferable. The air pressure after air supply is 250 as described above.
When the pressure is set in the range of 600 mmAq to 600 mmAq, the pressure relationship after air supply and exhaust can be in the range of 1/3 to 1/2, and a comfortable sleeping comfort can be given to the patient in a state of promoting blood circulation.

Now, when the operation is started by setting the pressure after air supply in the air mat 1 to, for example, 500 mmAq by the pressure setting device 9, the air pump 2 is driven, and the air discharged from the air pump 2 is silenced by the air tube 12a. Table 11
Sent to The silencer 11 has divided four chambers 11a, and while passing through these four chambers 11a, most of the pressure pulsation generated by the air pump 2 is smoothed, and air without pressure pulsation is supplied from the air tube 12b. The first air cell group ₁₁ and the second air cell group 11 of the air mat 1 are provided via the air switching valve 6.
Is supplied to the system air cell group _{1 2,} 500MmA air supply after air pressure in the first and second line air cell group ₁ 1, ₁ in ₂ setpoint
Inflated to q.

[0031] When the air supply after air pressure in the first and second line air cell group ₁ 1, ₁ in ₂ exceeds the 500mmAq settings, automatic control is started by the microcomputer 13a.

FIG. 10A shows a state immediately after the distribution groove 6j is positioned above the first discharge hole 6e and the limit switch 10 is switched from on to off. Limit switch 10
, The microcomputer 13a outputs a motor-off signal, and the rotation of the rotor 6b stops. The stop period T1 shown in FIG. 12 starting from this point is set to a predetermined period, for example, about 5 minutes by the built-in clock of the microcomputer 13a. During this period, the air from the air pump 2 is
g, a first discharge hole 6e, is supplied to the first system air cell group _{1 1} via the air tube 3a. The first system air cell group _{1 1} atmospheric pressure is maintained at about 475mmAq~525mmAq by switching the strong / weak operating the air pump 2 by the pressure sensor 5 and the signal processing circuit 8 and the control circuit 13.

That is, first, the first system air cell group ₁₁
Is higher than the set value of the pressure setting device 9, the output of the signal processing circuit 8 including the pressure sensor 5 is turned on, and the microcomputer 13a turns off (L) the control signal for the power switching circuit 13c. Thereby, the power switching circuit 13c
On the output side, the voltage which is dropped by the resistor 13h is outputted, the air pump 2 becomes a weak operation, the air pump 2, first and second line air cell group 1 _1, 1 ₂ and the air switching valve 6 60-90% of the leaked amount
Only reduced the air because they are not supplied to the first system air cell group 1 ₁ through the air switching valve 6, the air of the first system air cell group 1 ₁ gradually decreases, also the first system air cell group 1 ₁ atmospheric pressure at the same time And the set value of the pressure setting device 9 is 500 mmAq
In contrast, the pressure conversion value of the hysteresis voltage of the voltage comparator 8b in the signal processing circuit 8 (hereinafter referred to as the hysteresis pressure)
Becomes lower than the pressure reduced by 25 mmAq. As a result, the output of the signal processing circuit 8 is turned off, and the microcomputer 13a receiving the signal turns on (H) the control signal for the power switching circuit 13c. it supplies air rated flow in the first system air cell group 1 _1, the first system air cell group 1
_1. Increase the air pressure. And the first system air cell group ₁₁
When the pressure of the air becomes higher than the set value of 500 mmAq of the pressure setting device 9 by 25 mmAq or more of the “hysteresis pressure”, the output of the signal processing circuit 8 is turned on again, so that the air pump is operated by the microcomputer 13a and the power switching circuit 13c as described above. 2 becomes "weak driving" again.

By repeating the above operation, the air pressure in the _first air cell group 11 becomes about 475 mmAq to 525 mm.
mmAq is maintained. Also at this point the second system air cell group 1 ₂ is evacuated and sealed while maintaining the approximately 250 mmAq.

In FIG. 10B, after the period T1, a motor-on signal is output from the microcomputer 13a via the on / off circuit 13b, and the rotor 6b starts rotating in the direction of the arrow X in the figure. It shows the state that it is doing. Accordingly distribution groove 6j moves onto the second discharge hole 6f over the first discharge hole 6e, the air supply to the first system air cell group 1 ₁ stops, to the second system air cell group 1 ₂ Start air supply. The drive period T2 of the motor 7 is determined by the microcomputer 13a when the limit switch 10 is turned on. At the same time air supply halfway into the second system air cell group 1 ₂ This period is started, the pressure sensor 5 senses the low pressure of the second system air cell group 1 _2, via the signal processing circuit 8 Then, a signal is output to the microcomputer 13a and the power switching circuit 13c to set the air pump 2 to "strong operation". And until now is the second system air cell group 1 ₂ pressure increases the hysteresis pressure higher than the set value of the pressure setting device 9, the "strong operation" continues. Thereafter, when a is performed switching of strong / weak driving the air pump 2 by the same operation in the period T1, the second system air cell group 1 ₂ atmospheric pressure to about 47
It is maintained at 5 mmAq to 525 mmAq.

On the other hand, the first system air cell group _{1 1} atmospheric pressure is sealed in the range of middle about 475mmAq~525mmAq this period. Thereafter, the pressure sensor 5 to the state of (f) of FIG. 11 will be the first system air cell group 1 ₁ air pressure is not detected. FIG. 10C shows a period T2.
, The motor-off signal is output from the microcomputer 13a, and the rotor 6b is stopped. The suspension period T3 is set to about one minute. The second air supply to the system air cell group 1 ₂ is carried out during the period T2, and the period T3. FIG.
Each air cell group 1 of the air mat in the state of 0 (c)
_1, 1 ₂ of the pressure control is performed in substantially the same manner as the pressure control in the state of (b) of FIG. 10. After the elapse of the period T3 shown in FIG. 12, the microcomputer 13a outputs a motor-on signal and the motor 7 rotates.

FIG. 10D shows the driving period T of the motor 7.
4 (about 6 seconds), the motor-off signal is output and the motor 7 is stopped. This period T4
Is set to coincide with the time when the exhaust hole 6k of the rotor 6b is located on the first exhaust hole 6e. At this position, the rotor 6b stops for a period T5 (about 4 seconds). The period T5 is the first line air cell group 1 ₁ of the exhaust time, the cells in the residual pressure is adjusted as a time until reduced to about 250 mmAq. After the elapse of the period T5, the motor 7 starts rotating according to the motor-on signal from the microcomputer 13a, and continues to rotate during the period T6. During this period, the pressure sensor 5, the signal processing circuit 8, switching control of the air pressure by the strong / weak operating the air pump 2 due power switching circuit 13b is performed only for the second system air cell group 1 _2.

FIG. 11 (e) shows a state in which the limit switch 10 has passed the protrusion 6n due to the rotation of the rotor 6b, and has been switched from ON to OFF. In response to this off signal, a motor off signal is output from the microcomputer 13a, and the motor 7 stops. From this point on, the motor 7 keeps stopping for a period T7 set by the microcomputer 13a for about 5 minutes. This period T7 is set by the microcomputer 13a as a period having the same properties as the above-described period T1. During this time, although the first system air cell group _{1 1} is sealed by an exhaust state (residual pressure of about 250 mmAq), with the second system air cell group _{1 2} supply air condition, duration of the state of (a) the pressure is above FIG 10 in T1, the same operation as that performed with respect to the first system air cell group _{1 1,} about the switching of the strong / weak driving the air pump 2 475MmAq～525
mmAq is maintained. After a period T7 shown in FIG. 12 has elapsed, a motor-on signal is output from the microcomputer 13a, and the motor 7 starts rotating, and continues to rotate during a period T8 until the limit switch 10 is turned on.

[0039] (f) of FIG. 11 shows a state in which the distribution grooves 6j immediately rotation located on the first discharge hole 6e, the first air supply to the system air cell group 1 ₁ is started the motor 7 I have. In this state, at the same time the air supply to the first system air cell group 1 ₁ is started, the pressure sensor 5 detects the first system air cell group 1 ₁ low pressure (residual pressure of about 250 mmAq),
A signal is output to the microcomputer 13a and the power switching circuit 13c via the signal processing circuit 8 to set the air pump 2 to "strong operation". And again the first system air cell group 1 ₁ atmospheric pressure, until a higher than the hysteresis pressure than the set value of the pressure setting device 9, the "strong operation" continues. Thereafter, the a is performed switching of strong / weak operation of the air pump 2 by the same operation in the period T1, the first system air cell group _{1 1} atmospheric pressure is maintained at about 475MmAq～525mmAq.

On the other hand, the second system air cell group _{1 2} atmospheric pressure,
During this period, sealing is performed in a range of about 475 mmAq to 525 mmAq. Thereafter again the next rotational period of the air switching valve 6, the above-mentioned pressure sensor 5 to the state of (b) in FIG. 10 so that the second system air cell group 1 ₂ pressure is not detected. FIG. 11 (g) shows that the limit switch 10 rides on the protrusion 6m at the end of the period T8,
This shows a state where the switch is turned on. After the elapse of the period T8,
The microcomputer 13a outputs a motor-off signal, and the motor 7 stops. During the subsequent period T9, the motor 7
Stops. Substantially over the entire period of time T8 and time T9, the air supply is made to the first system air cell group 1 _1. FIG.
(G) Each air cell group 1 of the air mat 1 in the state of (g)
_1, 1 ₂ of the pressure control is performed in substantially the same manner as the pressure control in the state of (f) of FIG. 11. After the elapse of the period T9, the motor 7 starts rotating.

FIG. 11 (h), the exhaust hole 6k by the rotation of the rotor 6b is moved onto the second discharge hole 6f, shows a state in which the exhaust is started from the second line air cell group 1 _2.
When the period T10 elapses, the exhaust hole 6k becomes the second exhaust hole 6
f11, and a period T11 that continues at this position.
The motor 7 stops for (about 4 seconds). This suspension period T
11 during the exhaust of the second system air cell group 1 ₂ is continued,
The pressure drops to about 250 mmAq. During this period, the pressure sensor 5, the signal processing circuit 8, switching control of the air pressure by the strong / weak operating the air pump 2 due power switching circuit 13c is performed only for the first system air cell group 1 _1.

After the elapse of the period T11, the microcomputer 13a
Outputs a motor-on signal to rotate the motor 7, the exhaust hole 6k passes over the second exhaust hole 6f, and the exhaust operation ends. When the limit switch 10 passes through the protrusion 6m due to the rotation of the motor 7 and the rotor 6b, the limit switch 10 is turned off and the motor 7 stops. In such a state, the first system air cell group ₁₁
In the same manner as in the period T1, switching between the strong / weak operation of the air pump 2 is performed, and the air pressure in the cell is maintained at about 475 mmAq to 525 mmAq.

Meanwhile, the second system air cell group _{1 2,} about 25
Sealed and maintained at a low pressure of 0 mmAq. When the motor 7 and the period T12 that is the rotation of the rotor 6b is completed, the first and second air cell unit 1 _1, 1 ₂ of the air supply and one cycle of the discharging operation is terminated. After that, the period T1 again
A similar cycle is repeated in a period T12.

The above description of the operation with reference to FIGS. 10 to 12 relates to an air mat for preventing bedsore, but the air mat 1 can also be used as an air mat for a healthy person. In this case, the air pressure after air supply can be adjusted by adjusting a pressure regulating valve provided in the air pump 2, and the air pressure after exhaust air can be adjusted by adjusting the period T5 or by adjusting the number of small holes of the exhaust holes 6k. .

The signal processing circuit 8 including the pressure sensor 5 and the control circuit 13 described in the above embodiment are merely examples, and are not necessarily limited to these circuits. The output of the signal processing circuit 8 may be applied directly to the power switching circuit 13c without passing through the microcomputer 13a. In this case, when the output signal of the signal processing circuit 8 is turned on (H), , Power switching circuit 13
It is necessary to invert the signal with an inverter or the like so that the signal input to c is turned off (L). Further, in the above embodiment, a single-phase AC 100 V is used as the power supply of the air pump 2, but other power supplies, for example, a DC power supply may be used.

[0046]

As described in detail above, the present invention operates the air pump strongly only when it is necessary to supply air to the air mat, and switches the operation to the weak operation when the pressure in the air mat reaches a set value.・ Because less air was supplied from the air pump than the amount corresponding to the amount of air leakage from the second system air cell group and the route leading to this, compared to the conventional air pump that repeatedly starts and stops the air pump, The frequency of switching between strong operation and weak operation can be greatly reduced, which can reduce harsh noise and generate no electrical noise such as voltage spikes. There is no need to worry about adverse effects on measuring instruments.

Further, since the operation and stop of the air pump are not repeated, problems such as a shortening of the service life of the switching element do not occur, and the pressure in the air mat does not fluctuate greatly. There is no need to worry about disturbing or bottoming out, giving the user discomfort.

In addition, when the air pump is weakly operated, the power consumption is not more than 20% of that in the strong operation, which is economical. In addition, since the amount of heat generated by the air pump can be reduced, the durability of the air pump can be improved.

[Brief description of the drawings]

FIG. 1 is a partially cutaway perspective view showing an air mat and an air supply device according to an embodiment of the present invention.

FIG. 2 is a plan view of the air supply device according to the embodiment of the present invention.

FIG. 3 is a cross-sectional view of an air switching valve used in the air supply device according to the embodiment of the present invention.

FIG. 4 is a plan view of a fixing plate of the air switching valve used in the air supply device according to the embodiment of the present invention.

FIG. 5 is a plan view of a rotor of an air switching valve used in the air supply device according to the embodiment of the present invention.

FIG. 6 is a front view of a pressure sensor used in the air supply device according to the embodiment of the present invention.

FIG. 7 is a circuit diagram showing a signal processing circuit of the air supply device according to the embodiment of the present invention.

FIG. 8 is a circuit diagram showing a control system of the air supply device according to the embodiment of the present invention.

FIG. 9 is a circuit diagram showing a power switching circuit of the air supply device according to the embodiment of the present invention.

FIGS. 10 (a) and (b) are explanatory views of the operation of an air switching valve used in the air supply device according to the embodiment of the present invention.

FIGS. 11 (e) to (h) are explanatory diagrams of the operation of the air switching valve used in the air supply device according to the embodiment of the present invention.

FIG. 12 is a timing chart showing the operation of the air supply device according to the embodiment of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Air mat, 1 ₁ ... 1st system air cell group, 1 ₂ ... 2nd system air cell group, 2 ... Air pump, 5 ... Pressure sensor,
6 air switching valve, 11 muffler, 12a air tube, 13 control circuit.

Claims (3)

[Claims] 1. A first device comprising a plurality of tubular air cells.
And air mattress 1 which is formed by arranging the system air cell group 1 ₁ and the second system air cell group 1 ₂ alternately, the first and by switching the air pressure set by regulator in advance by a pressure measuring device 9 every predetermined time the second was supplied to the system air cell group 1 _1, 1 _2, the first and second system air cell groups every predetermined time 1 _1, 1 ₂ the air switching valve switches the supply and discharge of air to open to the atmosphere 6 When a pressure sensor 5 for detecting the pressure of the air switching valve 6 and provided in the middle of the air tube 12a which connects the air pump 2, and the first system air cell group 1 ₁ and the second system air cell group 1 in ₂ , the pressure sensor 5 first and second system air cell group encounters 1 _1, 1 pressure in the _2, the air pump 2 strongly operated when less than the predetermined set value, the first and second lines air cell group 1 , 1 when the pressure in ₂ reaches higher than the set value is less than the amount corresponding to the air leakage amount from the first and second line air cell group 1 _1, 1 ₂ and the path leading to this air from the air pump 2 An air supply device for an air mat, comprising: a control circuit 13 for weakly operating the air pump 2 so as to be supplied. 2. The air supply device for an air mat according to claim 1, wherein the air pump is controlled so that 60 to 90% of the amount of air leakage is discharged from the air pump 2 when the air pump 2 is weakly operated. 3. The air supply device for an air mat according to claim 1, wherein a silencer is connected in the middle of an air tube connecting the air pump and the pressure sensor.