Patent Description:
A pressure regulating apparatus that pressurizes a pressurization target object using air as a medium and decreases the pressure of the pressurization target object is used to supply air to, for example, the cuff of an electronic sphygmomanometer. <CIT> (literature <NUM>) discloses a pressure regulating apparatus of this type. The pressure regulating apparatus includes a pump that supplies air to the cuff of an electronic sphygmomanometer, and a slow exhaust valve that exhausts air filled in the cuff gradually at a constant speed during blood pressure measurement.

<CIT> (literature <NUM>) discloses a diaphragm pump as an example of the pump capable of supplying air to the cuff of an electronic sphygmomanometer. The diaphragm pump is configured to convert the rotation of a motor into a reciprocating motion, transmit the reciprocating motion to the pump portion of the diaphragm, suck air into the pump portion in a process in which the pump portion expands, and discharge the air in a process in which the pump portion contracts. A further diaphragm pump suitable for a pressure regulating apparatus is for example known from document <CIT>, which discloses the technical features of the preamble of claim <NUM>.

The pressure regulating apparatus disclosed in literature <NUM> uses a slow exhaust valve to regulate the pressure. This increases the number of parts and the manufacturing cost.

It is an object of the present invention to provide a diaphragm pump and pressure regulating apparatus capable of regulating the pressure without using a slow exhaust valve in an exhaust system.

Provided is a diaphragm pump comprising a diaphragm including a cup-shaped pump portion, a pump chamber including a wall including the pump portion, a driving device connected to a bottom of the pump portion and configured to convert a rotation into a reciprocating motion and increase/decrease a capacity of the pump chamber, a fluid inlet, a fluid discharge port, and a fluid exhaust port that are open to outside of the diaphragm pump, a suction passage configured to make the pump chamber communicate with the fluid inlet, a suction valve configured to open/close the suction passage to make a fluid flow from the fluid inlet toward the pump chamber in a process in which the capacity of the pump chamber increases, a discharge passage configured to make the pump chamber communicate with the fluid discharge port, a discharge valve configured to open/close the discharge passage to make the fluid flow from the pump chamber toward the fluid discharge port in a process in which the capacity of the pump chamber decreases, and an exhaust passage configured to make the discharge passage communicate with the fluid exhaust port.

The exhaust passage may be connected to an area on a downstream side of the discharge valve in the discharge passage.

A width of the fluid exhaust port may be smaller than a width of the fluid discharge port.

The diaphragm pump may further comprise a diaphragm housing forming the pump chamber together with the diaphragm, and a cover attached to the diaphragm housing, and the exhaust passage may include a through hole formed in the cover.

The diaphragm pump may further comprise a diaphragm housing forming the pump chamber together with the diaphragm, and a cover attached to the diaphragm housing. The cover may include a discharge pipe. The fluid inlet, the fluid discharge port, and the fluid exhaust port may be formed in an outer surface of the cover. The suction passage may include a suction fluid chamber formed between the diaphragm housing and the cover, a first through hole formed in the diaphragm housing and configured to make the suction fluid chamber communicate with the pump chamber, and a second through hole formed in the cover and configured to make the fluid inlet communicate with the suction fluid chamber. The discharge passage may include a discharge fluid chamber formed between the diaphragm housing and the cover, a third through hole formed in the diaphragm housing and configured to make the discharge fluid chamber communicate with the pump chamber, and a hollow portion of the discharge pipe configured to make the fluid discharge port communicate with the discharge fluid chamber. The discharge passage may include a fourth through hole formed in the cover and configured to make the fluid discharge port communicate with the discharge fluid chamber.

According to the present invention, there is provided a pressure regulating apparatus comprising the above-described diaphragm pump, a motor configured to apply a rotational force to the driving device, and a control device configured to control an operation of the motor, wherein the control device is configured to control a rotational speed of the motor and regulate a pressure of the fluid discharged from the fluid discharge port.

The pressure regulating apparatus further comprises a fluid passage configured to make the discharge passage communicate with a pressurization target object, and an exhaust valve configured to selectively exhaust the fluid in the fluid passage. According to the present invention, the pressure regulating apparatus comprises a third exhaust port that is open to the outside of the diaphragm pump, and a third exhaust passage configured to make the third exhaust port communicate with an area on the upstream side from the fluid outlet of the discharge valve in the discharge passage.

The pressure regulating apparatus may further comprise a pressure sensor configured to detect a pressure in the fluid passage, and the control device may be configured to control the rotational speed based on the pressure detected by the pressure sensor.

The control device may be configured to control the rotational speed and regulate the pressure not only when the pressure is increased, but also when the pressure is decreased.

According to the present invention, there is provided a pressure regulating apparatus comprising a diaphragm including a cup-shaped pump portion, a pump chamber including a wall including the pump portion, a driving device connected to a bottom of the pump portion and configured to convert a rotation into a reciprocating motion and increase/decrease a capacity of the pump chamber, a motor configured to apply a rotational force to the driving device, a fluid inlet, a fluid discharge port, and a first exhaust port that are open to outside of the diaphragm pump, a suction passage configured to make the pump chamber communicate with the fluid inlet, a suction valve configured to open/close the suction passage to make a fluid flow from the fluid inlet toward the pump chamber in a process in which the capacity of the pump chamber increases, a discharge passage configured to make the pump chamber communicate with the fluid discharge port, a discharge valve configured to open/close the discharge passage to make the fluid flow from the pump chamber toward the fluid discharge port in a process in which the capacity of the pump chamber decreases, a first exhaust passage configured to make the first exhaust port communicate with an area in the discharge passage between a fluid outlet of the discharge valve and the fluid discharge port, a differential pressure regulating valve configured to close the first exhaust passage when a pressure on an upstream side from the fluid outlet of the discharge valve in the discharge passage is higher than a pressure in the first exhaust passage, and open the first exhaust passage when the pressure on the upstream side from the fluid outlet of the discharge valve in the discharge passage is not higher than the pressure in the first exhaust passage, and a control device configured to control an operation of the motor, wherein the control device is configured to control a rotational speed of the motor and regulate a pressure of the fluid discharged from the fluid discharge port.

The pressure regulating apparatus may further comprise a second exhaust port that is open to the outside of the diaphragm pump, and a second exhaust passage configured to make the second exhaust port communicate with the area in the discharge passage between the fluid outlet of the discharge valve and the fluid discharge port.

The second exhaust passage may always be open.

A width of the second exhaust port may be smaller than a width of the fluid discharge port.

The pressure regulating apparatus may further comprise a fluid passage configured to make the discharge passage communicate with a pressurization target object, and a pressure sensor configured to detect a pressure in the fluid passage, and the control device may be configured to control the rotational speed based on the pressure detected by the pressure sensor.

The discharge passage may include an input-side space arranged on the upstream side from the fluid outlet of the discharge valve, and an output-side space may be interposed between the first exhaust passage, and the area in the discharge passage between the fluid outlet of the discharge valve and the fluid discharge port. The input-side space may be separated from the output-side space by a partition including the differential pressure regulating valve.

The diaphragm pump may further comprise a diaphragm housing forming the pump chamber together with the pump portion of the diaphragm, a cover attached to the diaphragm housing, and a partition sandwiched between the diaphragm housing and the cover. An input-side space is formed between the diaphragm housing and the partition, and an output-side space is formed between the cover and the partition. The input-side space is part of the discharge passage and is arranged on the upstream side from the fluid outlet of the discharge valve. The output-side space is interposed between the first exhaust passage, and the area in the discharge passage between the fluid outlet of the discharge valve and the fluid discharge port. The partition includes the differential pressure regulating valve.

The fluid inlet, the fluid discharge port, the first exhaust port, the suction passage, the discharge passage, and the first exhaust passage may be formed in the cover. The second exhaust port and the second exhaust passage may be formed in the cover. The third exhaust port and the third exhaust passage may be formed in the cover. The partition may include a through hole configured to make the input-side space communicate with the third exhaust passage. The third exhaust passage/the through hole may always be open.

A diaphragm pump and a pressure regulating apparatus according to the first embodiment of the present invention will be described in detail with reference to <FIG>.

A pressure regulating apparatus <NUM> shown in <FIG> can be used as an apparatus that supplies air to, for example, a cuff A (pressurization target object) of an electronic sphygmomanometer. The pressure regulating apparatus <NUM> includes a pump driving motor <NUM>, a control device <NUM> that controls the operation of the pump driving motor <NUM>, an operation switch <NUM> connected to the control device <NUM>, a pressure sensor <NUM>, and an exhaust valve <NUM>. The control device <NUM> includes a pump control unit <NUM> and an exhaust valve control unit <NUM>.

The pump driving motor <NUM> receives power from the pump control unit <NUM> of the control device <NUM> to rotate and drive a diaphragm pump <NUM> (to be described later). The diaphragm pump <NUM> is driven by the pump driving motor <NUM> to supply air to the cuff A of the electronic sphygmomanometer, details of which will be described later. The pressure sensor <NUM> detects a pressure in an air passage B (fluid passage) between the diaphragm pump <NUM> and the cuff A, and sends the detected pressure as a signal to the control device <NUM>. The exhaust valve <NUM> is formed from an electromagnetic valve and selectively exhausts air in the air passage B into the atmosphere. The operation of the exhaust valve <NUM> is controlled by the exhaust valve control unit <NUM> of the control device <NUM>.

The pump control unit <NUM> of the control device <NUM> controls the rotational speed of the pump driving motor <NUM> based on the pressure detected by the pressure sensor <NUM>. The exhaust valve control unit <NUM> of the control device <NUM> controls the exhaust valve <NUM> to open the exhaust valve <NUM> when exhausting a residual pressure in the cuff A, and close it in other times. The operation of the control device <NUM> will be described later. The operation switch <NUM> is a switch that is manually operated to switch the control device <NUM> between ON and OFF.

As shown in <FIG>, the diaphragm pump <NUM> is attached to the pump driving motor <NUM> located at the lowermost position in <FIG>. The diaphragm pump <NUM> includes a driving unit <NUM> fixed to the pump driving motor <NUM>, and a valve unit <NUM> attached to the driving unit <NUM>.

The driving unit <NUM> includes a driving unit housing <NUM> fixed to the pump driving motor <NUM>, and a driving mechanism <NUM> (driving device) stored in the housing <NUM>. The housing <NUM> is formed into a bottomed cylindrical shape and fixed to the pump driving motor <NUM> by a fixing bolt (not shown). The driving mechanism <NUM> includes a crank body <NUM> attached to a rotating shaft <NUM> of the pump driving motor <NUM>, and a driving body <NUM> connected to the crank body <NUM> via a driving shaft <NUM>.

The driving shaft <NUM> is attached to the crank body <NUM> in a state in which it tilts in a predetermined direction with respect to the rotating shaft <NUM>. The driving body <NUM> includes a columnar shaft portion <NUM> and a plurality of arm portions <NUM> projecting outward from the shaft portion <NUM> in the radial direction. The shaft portion <NUM> has a center hole in which the driving shaft <NUM> is inserted, and is rotatably supported by the driving shaft <NUM>. The arm portions <NUM> are provided for respective pump portions <NUM> of a diaphragm <NUM> (to be described later) and radially extend outward from the shaft portion <NUM> in the radial direction. A through hole 21a is formed in each arm portion <NUM>. A connecting piece <NUM> of the diaphragm <NUM> is inserted in the through hole 21a. The connecting piece <NUM> extends through the arm portion <NUM> and is fixed to the arm portion <NUM> in this state.

According to the driving mechanism <NUM>, a rotational force is applied from the rotating shaft <NUM> of the pump driving motor <NUM> to rotate the crank body <NUM> and the driving shaft <NUM>. The driving body <NUM> swings, and each pump portion <NUM> of the diaphragm <NUM> repetitively contracts and expands. That is, the driving mechanism <NUM> converts the rotation of the crank body <NUM> into a reciprocating motion to increase/decrease the capacity of a pump chamber <NUM> in the pump portion <NUM>.

The valve unit <NUM> includes the diaphragm <NUM> connected to the driving body <NUM>, a diaphragm holder <NUM> attached to the opening portion of the driving unit housing <NUM>, a diaphragm housing <NUM> attached to the diaphragm holder <NUM> via the diaphragm <NUM>, and a cover <NUM> attached to the diaphragm housing <NUM>. The diaphragm <NUM> is sandwiched between the diaphragm holder <NUM> and the diaphragm housing <NUM>. The diaphragm holder <NUM>, the diaphragm housing <NUM>, and the cover <NUM> are each formed into a circular shape when viewed from the axial direction of the pump driving motor <NUM>.

The diaphragm holder <NUM> is formed into a cylindrical shape connectable to the driving unit housing <NUM>, and includes a plurality of cylinder holes <NUM> in which the pump portions <NUM> of the diaphragm <NUM> (to be described later) are inserted.

The diaphragm <NUM> includes the plurality of cup-shaped pump portions <NUM> that are open toward the diaphragm housing <NUM>. The pump portions <NUM> are provided at positions at which the diaphragm <NUM> is divided into a plurality of parts in the circumferential direction of the cylindrical diaphragm holder <NUM>. Each pump portion <NUM> is inserted into the cylinder hole <NUM> formed in the diaphragm holder <NUM>. The opening portion of the pump portion <NUM> is closed by the diaphragm housing <NUM>. The pump chamber <NUM> using the pump portion <NUM> as part of the wall is formed between the pump portion <NUM> and the diaphragm housing <NUM>.

A piston <NUM> is provided on the bottom of the cup-shaped pump portion <NUM>. The connecting piece <NUM> projects from the piston <NUM> in a direction opposite to the pump chamber <NUM>. As described above, the connecting piece <NUM> is connected to the driving body <NUM> of the driving mechanism <NUM>. The driving mechanism <NUM> is connected to the bottom of the pump portion <NUM>. When the driving body <NUM> of the driving mechanism <NUM> swings, the bottom (piston <NUM>) of the pump portion <NUM> comes into contact with or moves apart from the diaphragm housing <NUM> to increase/decrease the capacity of the pump chamber <NUM>.

The diaphragm housing <NUM> is formed into a disk shape. An annular suction fluid chamber <NUM> is formed at an outer peripheral portion between the diaphragm housing <NUM> and the cover <NUM>. A discharge fluid chamber <NUM> is formed on the center side between the diaphragm housing <NUM> and the cover <NUM>. The suction fluid chamber <NUM> and the discharge fluid chamber <NUM> are separated by a cylindrical wall <NUM>.

A plurality of first through holes <NUM> are formed on the outer peripheral side of the diaphragm housing <NUM> and provided for the respective pump chambers <NUM>. The first through holes <NUM> make the suction fluid chamber <NUM> communicate with the pump chambers <NUM>. A fluid inlet <NUM> is formed in the outer surface of the cover <NUM> and open to the outside of the diaphragm pump <NUM>. A second through hole <NUM> is further formed in the cover <NUM> and makes the fluid inlet <NUM> communicate with the suction fluid chamber <NUM>. The suction fluid chamber <NUM> communicates with the atmosphere via the second through hole <NUM>. In this embodiment, the first through holes <NUM> provided for the respective pump chambers <NUM>, the suction fluid chamber <NUM>, the second through hole <NUM>, and the like form a suction passage <NUM> that makes the pump chambers <NUM> communicate with the fluid inlet <NUM> outside the pump. That is, one end of the suction passage <NUM> is connected to the pump chamber <NUM>, and the other end of the suction passage <NUM> is connected to the fluid inlet <NUM>.

The diaphragm housing <NUM> supports on its outer peripheral side a plurality of suction valves <NUM> provided for the respective pump chambers <NUM>. Each suction valve <NUM> opens/closes the suction passage <NUM> and is formed into a predetermined shape by a rubber material. The suction valve <NUM> includes a shaft portion 41a that extends through the diaphragm housing <NUM> and is fixed to the diaphragm housing <NUM>, and a valve element 41b formed into a disk shape at the distal end of the shaft portion 41a. The valve element 41b is arranged at a position where it overlaps the opening portion of the first through hole <NUM> in the pump chamber <NUM>. The valve element 41b opens the opening portion of the first through hole <NUM> in a process in which the pump portion <NUM> of the diaphragm <NUM> expands to increase the capacity of the pump chamber <NUM>, and closes the opening portion of the first through hole <NUM> in a process in which the pump portion <NUM> contracts to decrease the capacity of the pump chamber <NUM>. That is, the suction valve <NUM> opens/closes the suction passage <NUM> so that a fluid flows from the fluid inlet <NUM> toward the pump chamber <NUM> in a process in which the capacity of the pump chamber <NUM> increases.

A plurality of third through holes <NUM> are formed on the center side of the diaphragm housing <NUM> and provided for the respective pump chambers <NUM>. The third through holes <NUM> make the discharge fluid chambers <NUM> communicate with pump chambers <NUM>. A discharge pipe <NUM> projects from the center portion of the cover <NUM>. A fluid discharge port <NUM> is formed at the distal end (outer surface of the cover <NUM>) of the discharge pipe <NUM> and open to the outside of the diaphragm pump <NUM>. A hollow portion 52a of the discharge pipe <NUM> extends from the fluid discharge port <NUM> to the discharge fluid chamber <NUM>. The discharge fluid chamber <NUM> therefore communicates with the atmosphere via the discharge pipe <NUM>. In this embodiment, the third through holes <NUM> provided for the respective pump chambers <NUM>, the discharge fluid chamber <NUM>, the hollow portion 52a of the discharge pipe <NUM>, and the like constitute a discharge passage <NUM> that makes the pump chambers <NUM> communicate with the fluid discharge port <NUM>. That is, one end of the discharge passage <NUM> is connected to the pump chamber <NUM>, and the other end of the discharge passage <NUM> is connected to the fluid discharge port <NUM> outside the pump.

The discharge pipe <NUM> is connected to, for example, the cuff A of the electronic sphygmomanometer via an air hose constituting the air passage B. The above-described pressure sensor <NUM> is arranged in the air passage B that makes the discharge passage <NUM> communicate with the cuff A, and detects a pressure in the air passage B. The above-described exhaust valve <NUM> is also provided in the air passage B.

The diaphragm housing <NUM> supports a discharge valve <NUM> at the center portion. The discharge valve <NUM> is formed from a rubber material and includes a valve element 42a in tight contact with a wall surface of the diaphragm housing <NUM> on the discharge fluid chamber <NUM> side. The valve element 42a is arranged at a position where it overlaps the opening portions of the third through holes <NUM>. The valve element 42a closes the opening portion of the third through hole <NUM> in a process in which the pump portion <NUM> of the diaphragm <NUM> expands to increase the capacity of the pump chamber <NUM>, and opens the opening portion of the third through hole <NUM> in a process in which the pump portion <NUM> contracts to decrease the capacity of the pump chamber <NUM>. That is, the discharge valve <NUM> opens/closes the discharge passage <NUM> so that a fluid flows from the pump chamber <NUM> toward the fluid discharge port <NUM> in a process in which the capacity of the pump chamber <NUM> decreases.

A fluid exhaust port <NUM> is formed in the outer surface of the cover <NUM> at a portion where the cover <NUM> covers the discharge fluid chamber <NUM>, and is open to the outside of the diaphragm pump <NUM>. A fourth through hole <NUM> is further formed at this portion and makes the fluid exhaust port <NUM> communicate with the discharge fluid chamber <NUM>. The fourth through hole <NUM> is always open. The discharge fluid chamber <NUM> is part of the discharge passage <NUM>. In this embodiment, the fourth through hole <NUM> constitutes an exhaust passage <NUM> that makes the discharge passage <NUM> communicate with the fluid exhaust port <NUM>. That is, one end of the exhaust passage <NUM> is connected to the discharge passage <NUM> (more specifically, connected to an area on the downstream side of the discharge valve <NUM> in the discharge passage <NUM>), and the other end of the exhaust passage <NUM> is connected to the fluid exhaust port <NUM> outside the pump. Note that a plurality of fluid exhaust ports <NUM> and a plurality of fourth through holes <NUM> (exhaust passages <NUM>) may be formed in the cover <NUM>.

The width of the fluid exhaust port <NUM> is smaller than that of the fluid discharge port <NUM>, and the width of the fourth through hole <NUM> is smaller than that of the hollow portion 52a of the discharge pipe <NUM>. In other words, the width of the exhaust passage <NUM> is smaller than that of the narrowest portion of the discharge passage <NUM>.

In the diaphragm pump <NUM> having this structure, when the pump portion <NUM> of the diaphragm <NUM> expands to increase the capacity of the pump chamber <NUM>, the suction valve <NUM> opens to suck the atmosphere into the pump chamber <NUM> via the suction passage <NUM>. In contrast, when the pump portion <NUM> of the diaphragm <NUM> contracts to decrease the capacity of the pump chamber <NUM>, the discharge valve <NUM> opens to supply air in the pump chamber <NUM> to the discharge fluid chamber <NUM> via the third through hole <NUM>. Most of the air flowing into the discharge fluid chamber <NUM> is discharged from the fluid discharge port <NUM> via the hollow portion 52a (discharge passage <NUM>) of the discharge pipe <NUM> and sent to the cuff A via the air hose (air passage B).

Part of the air flowing into the discharge fluid chamber <NUM> is exhausted into the atmosphere via the exhaust passage <NUM>. The discharge pressure of air discharged from the fluid discharge port <NUM> can be easily regulated by controlling the rotational speed of the motor <NUM> to adjust the balance between the discharge amount and the exhaust amount.

When the cuff A is connected to the discharge pipe <NUM> via the air hose, the pressure in the discharge fluid chamber <NUM> and the exhaust amount of air exhausted from the fluid exhaust port <NUM> via the exhaust passage <NUM> are uniquely determined by determining the rotational speed of the pump driving motor <NUM>. If the rotational speed of the pump driving motor <NUM> changes, the pressure in the discharge fluid chamber <NUM> and the exhaust amount also change in correspondence with the change of the rotational speed. The pressure in the discharge fluid chamber <NUM> almost coincides with the discharge pressure of air discharged from the fluid discharge port <NUM>, that is, the discharge pressure of the diaphragm pump <NUM>. The discharge pressure of the diaphragm pump <NUM> changes in correspondence with the rotational speed of the pump driving motor <NUM>, as shown in, for example, the graph of <FIG>. The discharge pressure can be regulated to a desired value by controlling the rotational speed of the pump driving motor <NUM> by the pump control unit <NUM> of the control device <NUM>.

The correspondence between the rotational speed of the pump driving motor <NUM> and the discharge pressure of the diaphragm pump <NUM> is established not only when the discharge pressure is increased, but also when it is decreased. According to this embodiment, the discharge pressure can be regulated to a desired value by only controlling the rotational speed of the pump driving motor <NUM> not only when the discharge pressure is increased, but also when it is decreased.

In this embodiment, the pump control unit <NUM> of the control device <NUM> controls the rotational speed of the pump driving motor <NUM> based on a pressure in the air passage B detected by the pressure sensor <NUM>. More specifically, the pump control unit <NUM> obtains a difference between a target pressure and a detected pressure, when the target pressure is higher, increases the rotational speed, and when it is lower, decreases the rotational speed, thereby adjusting the detected pressure close to the target pressure. Note that the pump control unit <NUM> may hold in advance data representing the correspondence between the rotational speed of the pump driving motor <NUM> and the discharge pressure of the diaphragm pump <NUM>, as shown in <FIG>, and control the rotational speed of the pump driving motor <NUM> based on the data without using a pressure detected by the pressure sensor <NUM>.

When the pressure regulating apparatus <NUM> according to this embodiment is mounted in an electronic sphygmomanometer, the pump control unit <NUM> of the control device <NUM> controls the rotational speed of the pump driving motor <NUM> so that the discharge pressure of the diaphragm pump <NUM> changes in a pattern suited to blood pressure measurement. That is, as shown in <FIG>, the pump control unit <NUM> increases the rotational speed of the pump driving motor <NUM> so that the pressure of the cuff A reaches a predetermined initial pressure P1, and then gradually decreases the rotational speed of the pump driving motor <NUM>. When the rotational speed of the pump driving motor <NUM> decreases, the discharge pressure gradually lowers because air is always exhausted from the discharge fluid chamber <NUM> via the exhaust passage <NUM>.

The electronic sphygmomanometer starts blood pressure measurement when the discharge pressure lowers to P2 in a process in which the discharge pressure gradually lowers. When the discharge pressure reaches P3 after the end of blood pressure measurement, the pump control unit <NUM> stops the pump driving motor <NUM>. Even after the pump driving motor <NUM> stops, the air in the discharge fluid chamber <NUM> keeps exhausted into the atmosphere from the exhaust passage <NUM>. When the discharge pressure reaches P3, the exhaust valve control unit <NUM> controls the exhaust valve <NUM> to open. When the exhaust valve <NUM> opens, the air in the air passage B is exhausted into the atmosphere and the cuff A contracts to an initial shape.

According to the first embodiment, the pressure in the discharge passage <NUM> can be regulated by changing the rotational speed of the driving mechanism <NUM> (driving device) of the diaphragm pump <NUM> without using a slow exhaust valve in the discharge passage <NUM> of the diaphragm pump <NUM>. Since a slow exhaust valve is unnecessary, the manufacturing costs of the diaphragm pump and pressure regulating apparatus can be reduced. There can be provided a low-cost diaphragm pump and pressure regulating apparatus capable of regulating the pressure without using a slow exhaust valve.

A pressure regulating apparatus according to the second embodiment of the present invention will be described in detail with reference to <FIG>.

A pressure regulating apparatus <NUM> shown in <FIG> can be used as an apparatus that supplies air to, for example, a cuff A (pressurization target object) of an electronic sphygmomanometer. The pressure regulating apparatus <NUM> includes a pump driving motor <NUM>, a control device <NUM> that controls the operation of the pump driving motor <NUM>, an operation switch <NUM> connected to the control device <NUM>, and a pressure sensor <NUM>. The control device <NUM> includes a pump control unit <NUM>.

The pump driving motor <NUM> receives power from the pump control unit <NUM> of the control device <NUM> to rotate and drive a diaphragm pump <NUM> (to be described later). The diaphragm pump <NUM> is driven by the pump driving motor <NUM> to supply air to the cuff A of the electronic sphygmomanometer, details of which will be described later. The pressure sensor <NUM> detects a pressure in an air passage B (fluid passage) between the diaphragm pump <NUM> and the cuff A, and sends the detected pressure as a signal to the control device <NUM>.

The pump control unit <NUM> of the control device <NUM> controls the rotational speed of the pump driving motor <NUM> based on the pressure detected by the pressure sensor <NUM>. The operation of the control device <NUM> will be described later. The operation switch <NUM> is a switch that is manually operated to switch the control device <NUM> between ON and OFF.

The driving unit <NUM> includes a driving unit housing <NUM> fixed to the pump driving motor <NUM>, and a driving mechanism <NUM> (driving device) stored in the housing <NUM>. The housing <NUM> is formed into a bottomed cylindrical shape and fixed to the pump driving motor <NUM> by a fixing bolt (not shown). The driving mechanism <NUM> includes a crank body <NUM> attached to a rotating shaft <NUM> of the pump driving motor <NUM>, and a driving body <NUM> connected to the crank body <NUM>.

The driving body <NUM> includes a shaft portion 118a that tilts in a predetermined direction with respect to the rotating shaft <NUM>, and a plurality of arm portions 118b projecting outward from the middle portion of the shaft portion 118a in the radial direction. One end of the shaft portion 118a is engaged with the crank body <NUM> rotatably and swingably so that the shaft portion 118a can rotate about the rotating shaft <NUM> together with the crank body <NUM>. The other end of the shaft portion 118a is swingably supported by a diaphragm holder <NUM> attached to the opening portion of the housing <NUM>.

The arm portions 118b are provided for respective pump portions <NUM> of a diaphragm <NUM> (to be described later) and radially extend outward from the shaft portion 118a in the radial direction. <FIG> shows only one arm portion 118b, but the arm portions 118b equal in number to the pump portions <NUM> are provided actually. A through hole <NUM> is formed in each arm portion 118b. A connecting piece <NUM> of the diaphragm <NUM> is inserted in the through hole <NUM>. The connecting piece <NUM> extends through the arm portion 118b and is fixed to the arm portion 118b in this state.

According to the driving mechanism <NUM>, a rotational force is applied from the rotating shaft <NUM> of the pump driving motor <NUM> to rotate the crank body <NUM>. The driving body <NUM> swings, and each pump portion <NUM> of the diaphragm <NUM> repetitively contracts and expands. That is, the driving mechanism <NUM> converts the rotation of the crank body <NUM> into a reciprocating motion to increase/decrease the capacity of a pump chamber <NUM> in the pump portion <NUM>.

The valve unit <NUM> includes the diaphragm <NUM> connected to the driving body <NUM>, the diaphragm holder <NUM> attached to the opening portion of the driving unit housing <NUM>, a diaphragm housing <NUM> attached to the diaphragm holder <NUM> via the diaphragm <NUM>, and a cover <NUM> attached to the diaphragm housing <NUM> via a partition <NUM>. The diaphragm <NUM> is sandwiched between the diaphragm holder <NUM> and the diaphragm housing <NUM>. The diaphragm holder <NUM>, the diaphragm housing <NUM>, the partition <NUM>, and the cover <NUM> are each formed into a circular shape when viewed from the axial direction of the pump driving motor <NUM>.

The diaphragm holder <NUM> is formed into a cylindrical shape connectable to the driving unit housing <NUM>, and includes a plurality of cylinder holes <NUM> in which the pump portions <NUM> of the diaphragm <NUM> (to be described later) are inserted, and a concave portion <NUM> that is open toward the diaphragm <NUM>.

The diaphragm <NUM> includes the cup-shaped pump portions <NUM> that are open toward the diaphragm housing <NUM>, plate-shaped suction valves <NUM> each projecting inward from the peripheral portion of the opening portion of the corresponding pump portion <NUM>, and a cylindrical valve element <NUM> inserted in the concave portion <NUM> of the diaphragm holder <NUM>. The pump portions <NUM>, the suction valves <NUM>, and the cylindrical valve element <NUM> are provided at positions at which the diaphragm <NUM> is divided into a plurality of parts in the circumferential direction of the cylindrical diaphragm holder <NUM>.

Each pump portion <NUM> is inserted into the cylinder hole <NUM> formed in the diaphragm holder <NUM>. The opening portion of the pump portion <NUM> is closed by the diaphragm housing <NUM>. The pump chamber <NUM> using the corresponding pump portion <NUM> as part of the wall is formed between the pump portion <NUM> and the diaphragm housing <NUM>. A piston <NUM> is formed on the bottom of the cup-shaped pump portion <NUM>. The connecting piece <NUM> projects from the piston <NUM> in a direction opposite to the pump chamber <NUM>. As described above, the connecting piece <NUM> is connected to the driving body <NUM> of the driving mechanism <NUM>. The driving mechanism <NUM> is connected to the bottom of the pump portion <NUM>. When the driving body <NUM> of the driving mechanism <NUM> swings, the bottom (piston <NUM>) of the pump portion <NUM> comes into contact with or moves apart from the diaphragm housing <NUM> to increase/decrease the capacity of the pump chamber <NUM>.

The suction valve <NUM> opens/closes a suction passage <NUM> formed in the diaphragm housing <NUM>. The suction passage <NUM> is constituted by a first groove <NUM> formed in a mating surface between the diaphragm <NUM> and the diaphragm holder <NUM> in the diaphragm housing <NUM>. One end of the suction passage <NUM> is connected to the pump chamber <NUM> via the suction valve <NUM>, and the other end of the suction passage <NUM> is connected to a fluid inlet <NUM> that is open in the outer surface (outside the diaphragm pump <NUM>) of the diaphragm housing <NUM>. That is, the suction passage <NUM> makes the pump chamber <NUM> communicate with the fluid inlet <NUM> via the suction valve <NUM>.

The suction valve <NUM> opens the opening portion of one end of the suction passage <NUM> in a process in which the pump portion <NUM> of the diaphragm <NUM> expands to increase the capacity of the pump chamber <NUM>, and closes the opening portion in a process in which the pump portion <NUM> contracts to decrease the capacity of the pump chamber <NUM>. That is, the suction valve <NUM> opens/closes the suction passage <NUM> so that a fluid flows from the fluid inlet <NUM> toward the pump chamber <NUM> in a process in which the capacity of the pump chamber <NUM> increases.

The cylindrical valve element <NUM> constitutes a first check valve <NUM> together with a column <NUM> of the diaphragm housing <NUM>. The column <NUM> constitutes the valve seat of the first check valve <NUM>. The cylindrical valve element <NUM> is formed into a cylindrical shape covering the outer peripheral surface of the column <NUM>. The first check valve <NUM> is interposed between a second groove <NUM> and the concave portion <NUM> of the diaphragm holder <NUM>. The second groove <NUM> is formed in a surface mating with the diaphragm <NUM> in the diaphragm housing <NUM>. One end of the second groove <NUM> is open to the pump chamber <NUM>. The first check valve <NUM> is constituted so that air flows from the second groove <NUM> toward the concave portion <NUM>.

The inside of the concave portion <NUM> is connected to an input-side space <NUM> (to be described later) via an upstream-side space <NUM> formed between the diaphragm holder <NUM> and the diaphragm <NUM>, a first through hole <NUM> formed in the diaphragm <NUM>, and a second through hole <NUM> formed in the diaphragm housing <NUM>. The input-side space <NUM> is formed between the diaphragm housing <NUM> and the partition <NUM> (to be described later), and communicates with the pump chamber <NUM> via a continuous space from the second groove <NUM> to the second through hole <NUM>. Note that the input-side space <NUM> communicates with each of the pump chambers <NUM>.

The diaphragm housing <NUM> is formed into a plate shape, overlaps the diaphragm <NUM> to cover the opening portion of each pump portion <NUM>, and forms the pump chamber <NUM> together with the pump portion <NUM>.

The partition <NUM> is formed into a plate shape by an elastic member such as a rubber material including synthetic rubber. The partition <NUM> is sandwiched and held between the diaphragm housing <NUM> and the cover <NUM>, and separates the diaphragm housing <NUM> and the cover <NUM>. The above-described input-side space <NUM> is formed between the partition <NUM> and the diaphragm housing <NUM>, and an output-side space <NUM> is formed between the partition <NUM> and the cover <NUM>.

The output-side space <NUM> is separated from the input-side space <NUM> by the partition <NUM>. The output-side space <NUM> is connected to an outlet passage <NUM> in a discharge pipe <NUM> projecting from the center portion of the cover <NUM>, a first exhaust passage <NUM> formed in one side portion (left side portion in <FIG>) of the cover <NUM>, and a second exhaust passage <NUM> that is open in a concave portion <NUM> formed inside the center portion of the cover <NUM>. A third exhaust passage <NUM> is formed in the cover <NUM> so as to be adjacent to the output-side space <NUM>.

The outlet passage <NUM> in the discharge pipe <NUM> makes the inside of the concave portion <NUM> of the cover <NUM> communicate with a fluid discharge port 162a formed at the distal end of the discharge pipe <NUM>. The fluid discharge port 162a is open to the outer surface (outside the diaphragm pump <NUM>) of the discharge pipe <NUM>. The discharge pipe <NUM> is connected to, for example, the cuff A of the electronic sphygmomanometer via an air hose constituting the air passage B.

One end of the first exhaust passage <NUM> is connected to the output-side space <NUM>, and the other end of the first exhaust passage <NUM> is connected to a first exhaust port 163a that is open to the outer surface (outside the diaphragm pump <NUM>) of the cover <NUM>. That is, the first exhaust passage <NUM> makes the first exhaust port 163a communicate with an area between the fluid discharge port 162a and a fluid outlet 191a of a discharge valve <NUM> (to be described later) in a discharge passage <NUM> (to be described later).

One end of the second exhaust passage <NUM> is connected to the concave portion <NUM> (output-side space <NUM>) of the cover <NUM>, and the other end of the second exhaust passage <NUM> is connected to a second exhaust port 165a that is open to the outer surface (outside the diaphragm pump <NUM>) of the cover <NUM>. That is, the second exhaust passage <NUM> makes the second exhaust port 165a communicate with an area between the fluid discharge port 162a and the fluid outlet 191a of the discharge valve <NUM> (to be described later) in the discharge passage <NUM> (to be described later). The second exhaust passage <NUM> is always open. The hole diameter (width) of the second exhaust port 165a is smaller than that of the first exhaust port 163a. The width of the second exhaust port 165a is smaller than that of the fluid discharge port 162a, and the width of the second exhaust passage <NUM> is smaller than that of the outlet passage <NUM> in the discharge pipe <NUM>.

One end of the third exhaust passage <NUM> is open to a surface mating with the partition <NUM> in the cover <NUM>, and the other end of the third exhaust passage <NUM> is connected to a third exhaust port 166a that is open to the outer surface (outside the diaphragm pump <NUM>) of the cover <NUM>.

A cylindrical valve element <NUM> is formed in the partition <NUM> and projects toward the concave portion <NUM> of the cover <NUM>. The cylindrical valve element <NUM> constitutes a second check valve <NUM> together with a column <NUM> of the diaphragm housing <NUM>. The second check valve <NUM> makes air in the input-side space <NUM> flow into the concave portion <NUM> (output-side space <NUM>) of the cover <NUM>. The column <NUM> constitutes the valve seat of the second check valve <NUM>. The cylindrical valve element <NUM> is formed into a cylindrical shape covering the outer peripheral surface of the column <NUM>. The projecting end of the cylindrical valve element <NUM> is in contact with the outer peripheral surface of the column <NUM> all over the circumferential direction. The inner diameter of the base end portion of the cylindrical valve element <NUM> is larger than the outer diameter of the column <NUM>. The space between the base end portion of the cylindrical valve element <NUM> and the column <NUM> is part of the input-side space <NUM>, and constitutes part of the discharge passage <NUM> of the diaphragm pump <NUM>.

The discharge passage <NUM> is a passage that makes the pump chamber <NUM> communicate with the fluid discharge port 162a of the discharge pipe <NUM>. In this embodiment, the discharge passage <NUM> is constituted by the second groove <NUM> communicating with the pump chamber <NUM>, the space in the concave portion <NUM> of the diaphragm holder <NUM>, the upstream-side space <NUM>, the first and second through holes <NUM> and <NUM>, the input-side space <NUM>, the space in the concave portion <NUM> of the cover <NUM>, the outlet passage <NUM> in the discharge pipe <NUM>, and the like. The above-described first check valve <NUM> and second check valve <NUM> are provided in the discharge passage <NUM>, and air flows from the pump chamber <NUM> toward the outlet passage <NUM>.

In this embodiment, the first check valve <NUM> and the second check valve <NUM> constitute the discharge valve <NUM> of the diaphragm pump <NUM>. The discharge valve <NUM> closes the discharge passage <NUM> in a process in which the pump portion <NUM> of the diaphragm <NUM> expands to increase the capacity of the pump chamber <NUM>, and opens the discharge passage <NUM> in a process in which the pump portion <NUM> contracts to decrease the capacity of the pump chamber <NUM>. That is, the discharge valve <NUM> opens/closes the discharge passage <NUM> so that a fluid flows from the pump chamber <NUM> toward the fluid discharge port 162a in a process in which the capacity of the pump chamber <NUM> decreases.

The projecting end of the cylindrical valve element <NUM> and the outer peripheral surface of the column <NUM> constitute the fluid outlet 191a of the discharge valve <NUM>. One end of the first exhaust passage <NUM> is connected via the output-side space <NUM> to an area in the discharge passage <NUM> between the fluid outlet 191a of the discharge valve <NUM> and the fluid discharge port 162a of the discharge pipe <NUM>, and one end of the second exhaust passage <NUM> is also connected. The input-side space <NUM> is arranged on the upstream side from the fluid outlet 191a of the discharge valve <NUM>. The pressure on the downstream side from the fluid outlet 191a of the discharge valve <NUM> is almost equal to the pressure in the output-side space <NUM>, and the pressure on the upstream side from the fluid outlet 191a is almost equal to the pressure in the input-side space <NUM>.

A valve element <NUM> of a differential pressure regulating valve <NUM> (to be described later) and a third through hole <NUM> that receives a columnar projection <NUM> of the diaphragm housing <NUM> are formed in the partition <NUM>. The third through hole <NUM> is connected to the third exhaust passage <NUM>. The third exhaust passage <NUM> makes the third exhaust port 166a communicate with an area (input-side space <NUM>) on the upstream side from the fluid outlet 191a of the discharge valve <NUM> in the discharge passage <NUM>.

The differential pressure regulating valve <NUM> is constituted by the valve element <NUM> and a valve seat <NUM> in which the first exhaust passage <NUM> is open. The valve element <NUM> moves by a pressure difference between the input-side space <NUM> and the output-side space <NUM> to open/close the first exhaust passage <NUM>. When the pressure in the input-side space <NUM> is equal to or lower than that in the output-side space <NUM>, the valve element <NUM> comes into contact with the diaphragm housing <NUM>, as shown in <FIG>. When the pressure in the input-side space <NUM> becomes higher than that in the output-side space <NUM> and the pressure difference exceeds a predetermined value, the valve element <NUM> moves apart from the diaphragm housing <NUM> and is seated on the valve seat <NUM> of the cover <NUM>. When the valve element <NUM> is seated on the valve seat <NUM>, the first exhaust passage <NUM> is closed. That is, the differential pressure regulating valve <NUM> closes the first exhaust passage <NUM> when the pressure on the upstream side from the fluid outlet 191a of the discharge valve <NUM> in the discharge passage <NUM> is higher than that in the first exhaust passage <NUM>, and opens the discharge passage <NUM> when the pressure on the upstream side from the fluid outlet 191a of the discharge valve <NUM> in the discharge passage <NUM> is equal to or lower than that in the first exhaust passage <NUM>.

The inner diameter of the third through hole <NUM> of the partition <NUM> is slightly larger than the outer diameter of the columnar projection <NUM>. When the columnar projection <NUM> is inserted in the third through hole <NUM>, a small gap is formed between the hole wall surface of the third through hole <NUM> and the peripheral surface of the columnar projection <NUM>. The input-side space <NUM> is open to the atmosphere via the small gap between the columnar projection <NUM> and the third through hole <NUM> and the third exhaust passage <NUM> of the cover <NUM>.

In the diaphragm pump <NUM> having this structure, when the pump portion <NUM> of the diaphragm <NUM> expands to increase the capacity of the pump chamber <NUM>, the suction valve <NUM> opens to suck the atmosphere into the pump chamber <NUM> via the suction passage <NUM>.

In contrast, when the pump portion <NUM> of the diaphragm <NUM> contracts to decrease the capacity of the pump chamber <NUM>, the air in the pump chamber <NUM> is sent to the input-side space <NUM> via the second groove <NUM>, the first check valve <NUM>, the concave portion <NUM>, the upstream-side space <NUM>, and the first and second through holes <NUM> and <NUM>. At this time, the capacity of the pump chamber <NUM> decreases to pressurize the input-side space <NUM> and generate a pressure difference between the input-side space <NUM> and the output-side space <NUM>. When the pressure difference exceeds a predetermined value, the differential pressure regulating valve <NUM> operates. The operation of the differential pressure regulating valve <NUM> will be described in detail with reference to <FIG> and <FIG>.

<FIG> and <FIG> are sectional views for explaining the operation of the differential pressure regulating valve. In <FIG> and <FIG>, the same reference numerals denote the same or similar members as or to those described with reference to <FIG>, and a detailed description thereof will be omitted appropriately.

As shown in <FIG>, when a pressure Pin in the input-side space <NUM> becomes higher than a pressure Pout in the output-side space <NUM> by a predetermined pressure difference, the valve element <NUM> of the differential pressure regulating valve <NUM> is seated on the valve seat <NUM> and closes the first exhaust passage <NUM>. As indicated by arrows in <FIG>, most of air having passed through the second check valve <NUM> is discharged from the fluid discharge port 162a, and part of the air having passed through the second check valve <NUM> is exhausted from the second exhaust port 165a into the atmosphere. When an air hose is connected to the discharge pipe <NUM>, the air discharged from the fluid discharge port 162a is sent to the cuff A via the air hose (air passage B). At this time, part of the air in the input-side space <NUM> is exhausted into the atmosphere via the third through hole <NUM> and the third exhaust passage <NUM>.

Even if the motor <NUM> stops, the air in the input-side space <NUM> is exhausted into the atmosphere via the third exhaust passage <NUM>. As a result, the pressure Pin in the input-side space <NUM> becomes equal to or lower than the pressure Pout in the output-side space <NUM>, opening the differential pressure regulating valve <NUM>. When the differential pressure regulating valve <NUM> opens, the air in the output-side space <NUM> is exhausted into the atmosphere via the first exhaust passage <NUM>. At this time, the air in the discharge passage <NUM> between the fluid outlet 191a of the discharge valve <NUM> and the fluid discharge port 162a is exhausted into the atmosphere via the second exhaust passage <NUM>.

In the diaphragm pump <NUM> according to this embodiment, part of air having passed through the second check valve <NUM> is exhausted into the atmosphere via the second exhaust passage <NUM>. Part of air in the input-side space <NUM> is exhausted into the atmosphere via the third through hole <NUM> and the third exhaust passage <NUM>. The discharge pressure of air discharged from the fluid discharge port 162a can be easily regulated by controlling the rotational speed of the motor <NUM> to adjust the balance between the discharge amount and the exhaust amount.

When the cuff A is connected to the discharge pipe <NUM> via the air hose, the pressure in the discharge passage <NUM>, the exhaust amount of air exhausted from the second exhaust port 165a via the second exhaust passage <NUM>, and the exhaust amount of air exhausted from the third exhaust port 166a via the third exhaust passage <NUM> are uniquely determined by determining the rotational speed of the pump driving motor <NUM>. If the rotational speed of the pump driving motor <NUM> changes, the pressure in the discharge passage <NUM> and the two exhaust amounts also change in correspondence with the change of the rotational speed. The pressure in the discharge passage <NUM> almost coincides with the discharge pressure of air discharged from the fluid discharge port 162a, that is, the discharge pressure of the diaphragm pump <NUM>. The discharge pressure of the diaphragm pump <NUM> changes in correspondence with the rotational speed of the pump driving motor <NUM>, as shown in, for example, the graph of <FIG>. The discharge pressure can be regulated to a desired value by controlling the rotational speed of the pump driving motor <NUM> by the pump control unit <NUM> of the control device <NUM>.

When the pressure regulating apparatus <NUM> according to this embodiment is mounted in an electronic sphygmomanometer, the pump control unit <NUM> of the control device <NUM> controls the rotational speed of the pump driving motor <NUM> so that the discharge pressure of the diaphragm pump <NUM> changes in a pattern suited to blood pressure measurement. That is, as shown in <FIG>, the pump control unit <NUM> increases the rotational speed of the pump driving motor <NUM> so that the pressure of the cuff A reaches a predetermined initial pressure P1, and then gradually decreases the rotational speed of the pump driving motor <NUM>. When the rotational speed of the pump driving motor <NUM> decreases, the discharge pressure gradually lowers because air is always exhausted from the output-side space <NUM> via the second exhaust passage <NUM>.

The electronic sphygmomanometer starts blood pressure measurement when the discharge pressure lowers to a pressure P2 in a process in which the discharge pressure gradually lowers. When the discharge pressure reaches a pressure P3 from the pressure P2 after the end of blood pressure measurement, the pump control unit <NUM> stops the pump driving motor <NUM>. When the pump driving motor <NUM> stops, the differential pressure regulating valve <NUM> opens to exhaust the air in the output-side space <NUM> from the first exhaust passage <NUM> into the atmosphere. Also, the air in the output-side space <NUM> is exhausted from the second exhaust passage <NUM> into the atmosphere, and the air in the input-side space <NUM> is exhausted from the third exhaust passage <NUM> into the atmosphere. Accordingly, the cuff A contracts to an initial shape.

According to the second embodiment, the pressure in the discharge passage <NUM> can be regulated by changing the rotational speed of the driving mechanism <NUM> (driving device) of the diaphragm pump <NUM> without using a slow exhaust valve in the air passage B (exhaust system of the diaphragm pump <NUM>) between the diaphragm pump <NUM> and the cuff A. Since a slow exhaust valve is unnecessary, the manufacturing cost of the pressure regulating apparatus can be reduced. There can be provided a low-cost pressure regulating apparatus capable of regulating the pressure without using a slow exhaust valve in the exhaust system.

When the differential pressure regulating valve <NUM> is opened/closed by controlling the rotational speed of the pump driving motor <NUM>, the differential pressure regulating valve <NUM> may vibrate to generate a ripple of air. However, in the diaphragm pump <NUM> according to the second embodiment, air is always exhausted from the second exhaust passage <NUM>, the pressure is smoothened on the downstream side from the fluid outlet 191a of the discharge valve <NUM>, and thus the generation of a ripple can be suppressed. Even if the diaphragm pump <NUM> does not include the second exhaust passage <NUM>, it includes the third exhaust passage <NUM>, and the discharge pressure can be regulated by controlling the rotational speed of the pump driving motor <NUM> by the pump control unit <NUM> of the control device <NUM>.

Claim 1:
A pressure regulating apparatus (<NUM>) comprising:
a diaphragm (<NUM>) including a cup-shaped pump portion (<NUM>);
a pump chamber (<NUM>) including a wall including the pump portion;
a driving device (<NUM>) connected to a bottom of the pump portion and configured to convert a rotation into a reciprocating motion and increase/decrease a capacity of the pump chamber (<NUM>);
a motor (<NUM>) configured to apply a rotational force to the driving device;
a fluid inlet (<NUM>), a fluid discharge port (162a), and a first exhaust port (163a) that are open to outside of the diaphragm pump;
a suction passage (<NUM>) configured to make the pump chamber communicate with the fluid inlet;
a suction valve (<NUM>) configured to open/close the suction passage to make a fluid flow from the fluid inlet toward the pump chamber in a process in which the capacity of the pump chamber increases;
a discharge passage (<NUM>) configured to make the pump chamber communicate with the fluid discharge port;
a discharge valve (<NUM>) configured to open/close the discharge passage to make the fluid flow from the pump chamber toward the fluid discharge port in a process in which the capacity of the pump chamber decreases;
a first exhaust passage (<NUM>) configured to make the first exhaust port communicate with an area in the discharge passage between a fluid outlet (191a) of the discharge valve and the fluid discharge port;
a differential pressure regulating valve (<NUM>) configured to close the first exhaust passage when a pressure on an upstream side from the fluid outlet of the discharge valve in the discharge passage is higher than a pressure in the first exhaust passage, and open the first exhaust passage when the pressure on the upstream side from the fluid outlet of the discharge valve in the discharge passage is not higher than the pressure in the first exhaust passage; and
a control device (<NUM>) configured to control an operation of the motor, wherein the control device is configured to control a rotational speed of the motor and regulate a pressure of the fluid discharged from the fluid discharge port,
characterized in that the pressure regulating apparatus further comprises:
a third exhaust port (166a) that is open to the outside of the diaphragm pump; and
a third exhaust passage (<NUM>) configured to make the third exhaust port communicate with an area on the upstream side from the fluid outlet of the discharge valve in the discharge passage.