JP4944069B2 - pressure switch - Google Patents

Description

  The present invention relates to a pressure switch for controlling a prime mover of a pump based on a change in pressure when a flow path of liquid discharged from a pump is opened and closed.

For example, in an agricultural pump for spraying agricultural chemicals or the like, a spraying hose is connected to a discharge port of the agricultural pump. A nozzle for spraying liquid is attached to the tip of the spray hose, and a valve that can stop the liquid outflow to the nozzle is provided on the base end of the nozzle. Opens the valve when spraying and closes the valve when spraying stops.
In this case, the operation of the valve and the control of the prime mover on / off, etc. are not directly related to each other. If the prime mover is spraying, the valve is closed and the spraying of the liquid is stopped. And it will be rotating upset. In addition, when an unload valve is provided to reduce the load on the pump when spraying is stopped, the load on the pump may be reduced and the rotational speed of the prime mover may be increased when the bubble is closed.
Therefore, in a pump equipped with an unload valve, it is possible to control the rotational speed of the engine as a prime mover according to the pressure change on the inlet side of the unload valve when the bubble is closed and the unload valve is in the unload position. It has been proposed (see, for example, Patent Document 1).

In this case, an unload valve is provided at the proximal end of the passage of the liquid discharged from the pump, that is, in the vicinity of the pump, and the unload valve is provided between the inlet side, that is, between the discharge port of the pump and the unload valve. Piston-type hydraulic pressure detection means having a piston that operates by pressure change on the inlet side, control means for mechanically controlling the output of the engine, and transmission means for transmitting the operation of the piston to the control means .
When the bubble is closed, the unload valve changes from the load position to the unload position, and the fluid pressure on the inlet side of the unload valve is lower than the fluid pressure when the bubble is open. Based on the hydraulic pressure, the piston moves from a position where the hydraulic pressure is high to a position where the hydraulic pressure is low. This movement of the piston is transmitted to the control means, and the output of the engine is reduced.

When the bubble is opened again, the unload valve moves from the unload position to the load position, the fluid pressure rises, and the piston moves from the position when the fluid pressure is low to the position when the fluid pressure is high. . This is transmitted to the control means of the engine by the transmission means, and the output of the engine is increased to the state at the time of normal pump operation, so that the liquid can be sprayed.
In the above configuration, the piston that operates due to a pressure change may be changed to a pressure sensor. In this case, an electrical control means for controlling the operation of a prime mover such as an engine or a motor based on an electrical signal from the pressure sensor. Will be provided.

JP-A-63-19046

However, in the above-described method for controlling the prime mover of the pump by changing the pressure corresponding to the opening and closing of the valve, the unload valve has a piston (sliding member) that slides between the seal and the piston type hydraulic pressure detecting means. There is also a piston that slides against the seal.
Here, wet pumps may be used as agricultural chemicals in agricultural pumps. This wettable powder includes, for example, a fine powder and is dispersed in water. There is a risk that this fine powder will be caught between the piston and the seal, and malfunction may occur in the unload valve or piston type hydraulic pressure detection means having these seal and piston. Further, the seal and the sliding member are fixed by the wettable powder when not in use, and there is a risk of malfunctioning at startup.

Therefore, the liquid which can be used will be restrict | limited or will be in the state which requires frequent maintenance.
Further, the change in the hydraulic pressure on the spray side when the unload valve is used, that is, on the outlet side of the unload valve is as shown in the graph of FIG. The pressure difference in the pressure change between the load pressure when the load valve is at the load position and the sealed pressure when the load valve is closed (the fluid pressure when the unload valve is at the unload position) is not so large. In the case of leakage, the hydraulic pressure may be about the spray pressure and the unload valve may be in the load position, which may cause hunting.

Further, as shown in the graph of FIG. 14, when the valve is closed, a high hydraulic pressure peak occurs, which may cause the operation member of the unload valve to operate at a high speed and generate an impact and a high metallic noise. Therefore, it is necessary to try to mute the sound.
In addition, when a pressure sensor is used instead of the piston-type hydraulic pressure detecting means, the pressure sensor is not always easy to maintain and does not operate mechanically like a piston. The above-described electrical control means for controlling the motor based on the electrical signal from the pressure sensor is required, resulting in a complicated configuration and high cost.

  The present invention has been made in view of the above circumstances, and controls a prime mover such as a motor by detecting opening / closing of a discharge side flow path of a pump by a pressure change, and can prevent hunting with a simple configuration. The purpose is to provide.

In order to achieve the above object, the pressure switch according to claim 1 is a pressure that controls a prime mover of a pump using a pressure change in the flow path that occurs in response to opening and closing of the flow path of the liquid discharged from the pump. A switch,
A switch for switching the prime mover between a first control state which is a normal operation state and a second control state which is an operation state which is lower than normal or a stop state;
When a part is disposed in the predetermined space of the flow path and is movable between the first position and the second position, and the pressure in the predetermined space becomes relatively high due to the pressure change. When the switch is moved from the first position to the second position and the switch is in the first position, the switch is switched to the first control state and is held in the second position. A switch operating member for switching to and holding the control state;
By urging the switch operation member from the second position toward the first position, the switch operation at the second position when the inside of the predetermined space becomes a lower pressure than the high pressure. Biasing means for moving the member back to the first position;
Pressure loss means for generating a positional pressure difference in the predetermined space by generating a pressure loss when liquid is discharged by the pump;
And a pressure receiving member that receives the positional pressure difference in the predetermined space and presses the switch operating member from the second position side toward the first position side.

In the invention described in claim 1, since an unloading valve is not used, for example, the pressure switch of the present invention is provided in the discharge port portion of the pump, and a spray hose having a valve and a nozzle is connected to the tip thereof. In this case, when the pump is activated and the valve is opened, the switch operating member is biased to the first position side by the biasing means.
Also, when the pump is activated and the valve is open, the liquid discharged from the pump flows through the flow path on the protruding side of the pump, and a pressure difference based on the pressure loss occurs in the predetermined space by the pressure loss means. The pressure difference causes the pressure receiving member to push the switch operating member toward the first position.
That is, for example, in the state where the bubble near the nozzle is opened and the liquid is sprayed or discharged, the pressure receiving member that presses the switch operating member by the pressure difference based on the biasing force of the biasing unit and the pressure loss generated by the pressure loss unit With this pressing force, the switch operating member is pushed and held to the first position side.

Further, when the valve is closed, the discharge of the liquid from the nozzle is stopped while the pump is operating, so that the pressure in the flow path including the predetermined space on the discharge side of the pump increases. In this case, the switch operating member operates based on the increase in the internal pressure of the predetermined space and moves from the first position to the second position. In this case, a force larger than the urging force of the urging means is used. Thus, the switch operating member needs to be pressed from the first position to the second position.
Further, in this case, by closing the valve, even when the pump is operating, no liquid is discharged, no pressure loss is caused by the pressure loss means, and the switch operating member is moved to the first position by the pressure receiving member. There is no pressing force on the position side.

That is, in the state where the valve is opened and the liquid is discharged, the force from the second position to the first position on the switch operating member is a combination of the biasing means and the pressure receiving member. However, when the valve is closed, the force from the second position to the first position of the switch operating member is due to the urging means.
Therefore, the force that closes the valve and pushes the switch operating member in the predetermined space from the first position to the second position only needs to be larger than the urging force of the urging means. It is not necessary to be a combined power. Then, when the switch operation member reaches the second position from the first position, the switch is switched from the first control state to, for example, the stop state as the second control state, and the prime mover is in the first control state. From the normal operating state to the second control state, for example, a stop state is entered.

  Then, when the valve is opened again, the valve is opened, so that the pressure enclosed by closing the valve on the discharge side of the pump is released, and the pressure in the predetermined space is reduced. At this time, the force pushing the switch operation member based on the high pressure in the predetermined space also decreases based on the decrease in the pressure. When this force becomes less than the urging force of the urging means, the switch operation is performed. The member is moved to the first position by the urging force of the urging means, the switch is set to the first control state, and the prime mover is set to the normal operating state. As a result, the pump is operated, and the liquid discharged from the pump flows in the predetermined space.

As a result, the pressure in the predetermined space increases. At this time, the pressure receiving member receives the pressure difference due to the pressure loss described above, and the force by the pressure receiving member is added to the urging force of the urging means. Even when the switch is raised, the switch operating member is held in the first position, and the prime mover is maintained in a normal operating state.
From the above, a pressure difference due to pressure loss is generated, and the pressure operating member pushes the switch operating member toward the first position by the pressure difference, thereby reducing the urging force of the urging means.

Thereby, when the valve is closed, even if the sealed pressure in the predetermined space may be reduced, the force that pushes the switch operating member to the second position side based on the pressure in the predetermined space, Since the switch operating member does not move to the first position due to the urging force of the urging means unless the urging force of the urging means that has been reduced as described above is further reduced, the switch operation member will not be moved to the first position again. The switch does not enter the first control state and there is no possibility of hunting.
Therefore, hunting can be prevented. At this time, since the liquid does not flow in the predetermined space as described above, the switch does not generate a force to push the switch operating member to the first position side due to the pressure difference due to the pressure loss. The force that pushes the operating member toward the first position is the urging force of the urging means.

The pressure switch according to claim 2 is the invention according to claim 1,
The pressure receiving member divides the predetermined space into two spaces,
The pressure loss means allows the liquid discharged from the pump to flow over the two divided spaces, and is discharged from the operating pump to be discharged from one of the two spaces to the other space. A pressure loss is generated by the liquid flowing in the space, and a pressure difference is generated between the two spaces.

  In the invention described in claim 2, the pressure receiving member divides the inside of the predetermined space into two, and the liquid is discharged from the pump over the two spaces to cause a pressure loss, and a pressure difference is generated between the two spaces. Will occur. Then, a force acts on the pressure receiving member that divides the two spaces by this pressure difference, and the switch operating member is pushed to the first position side.

The pressure switch according to claim 3 is the invention according to claim 2,
The pressure receiving member is connected to the switch operating member and is a diaphragm that divides the predetermined space into two.

  In the invention according to claim 3, pressure loss is caused by flowing liquid between the spaces partitioned by the diaphragm by the pressure loss means, pressure loss is generated between the two spaces partitioned by the diaphragm, and the diaphragm It is possible to push the connected switch operating member toward the first position. That is, the diaphragm is elastically deformed by the pressure difference and pushes the switch operating member.

  Here, the switch operating member moves with elastic deformation of the diaphragm. Therefore, in order to separate the two spaces, it is not necessary to provide a seal between the switch operating member and the surrounding members and slide the switch operating member on the seal, and the two spaces are separated in a state where the diaphragm is stopped. It will be. Therefore, there is no structure in which the seal and the switch operation member slide, and the wettability does not cause a malfunction in the sliding portion between the seal and the switch operation member. That is, a wettable powder can be used, and even if a wettable powder is used, there is no malfunction, and maintenance can be prevented from becoming complicated.

A pressure switch according to a fourth aspect of the invention includes the cylindrical member according to the second aspect of the invention, wherein an internal space is the predetermined space,
The pressure receiving member functions as the switch operating member, and the internal space of the cylindrical member serving as the predetermined space is divided into two spaces that are aligned along the axial direction of the cylindrical member and the cylindrical shape The inside of the member is a piston that is movable between the first position and the second position along the axial direction of the cylindrical member.

In the invention according to claim 4, the piston divides the predetermined space inside the cylindrical member into two spaces, the piston moves due to a pressure difference in these divided spaces, and the piston serves as a switch operating member. It moves between the position 1 and the second position.
The structure as the pressure receiving member can be made stronger, and the pressure resistance can be improved.

The pressure switch according to claim 5 is the invention according to any one of claims 2 to 4,
The pressure loss means includes a flow path that allows the liquid discharged from the pump to flow over the two spaces partitioned by the pressure receiving member, a valve seat provided in the flow path, A valve body disposed on the downstream side of the valve seat of the liquid discharged from the pump, and valve body biasing means for biasing the valve body toward the valve seat,
The valve seat is formed with a groove that allows liquid to flow in the flow path even when the valve body comes into contact with the valve seat.

  In the fifth aspect of the invention, when the liquid discharged from the pump passes through the valve portion composed of the valve seat and the valve body, the liquid pushes the valve body that urges the valve body urging means. By pushing away from the valve seat, pressure loss occurs, and the pressure on the discharge side (for example, the hose side) from the valve body becomes lower than the pressure on the pump side from the valve body. Thereby, a pressing force can be applied to the pressure receiving member. Since the valve seat has a groove, the liquid can flow even when the valve body and the valve seat are in contact with each other and the valve is closed, and the flow of the liquid is stopped by closing the valve on the nozzle side. In such a case, the pressure can be relieved, and the pressure on the pump side when the valve is closed is relieved to the nozzle / hose side of the valve so that the same hydraulic pressure can be obtained on both sides of the valve.

In addition, after the pressure receiving member operates (displaces) due to the pressure difference based on the pressure loss in the valve, it returns to its original state when the pressure difference disappears. At this time, the liquid based on the operation of the pressure receiving member is closed. Can be moved in the groove of the valve seat. At this time, since the liquid must pass through the narrow groove, it is possible to prevent a sudden operation of the pressure receiving member, and it is possible to prevent a rapid operation of the switch operating member based on the operation of the pressure receiving member. Thereby, generation | occurrence | production of an impact sound can be prevented.
Further, since the groove is provided on the valve seat surface, it is possible to provide a structure in which foreign matter is not easily clogged when the valve element comes into contact with the valve seat.

  According to the pressure switch of the present invention, when the discharge of the liquid on the discharge side of the pump is opened and closed with a valve or the like, the pump prime mover is turned on or off or the output is increased or decreased according to the opening and closing. It becomes possible to control and hunting at this time can be prevented.

  The first embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram showing a schematic configuration of a spraying device having a pressure switch according to the first embodiment, FIG. 2 is a perspective view in which the pressure switch is attached to the reciprocating pump device, and FIG. 3 is a pressure switch of this embodiment. 4 is a perspective view of a reciprocating pump device as a pump to which a pressure device is attached, FIG. 5 is a side view of the reciprocating pump device, and FIG. 6 is a sectional view along the axial direction of a piston rod of the reciprocating pump device. 7 is a cross-sectional view taken along the line XX of FIG. 5, FIG. 8 is a cross-sectional view taken along a direction orthogonal to the piston rod of the reciprocating pump device, and FIGS. 9 and 10 are perspective views of a crankcase of the reciprocating pump device. 12 is a graph showing a pressure change in the B chamber in the pressure switch.

The pressure switch 10 of this example can be attached to, for example, the agricultural liquid spray device shown in FIG. 1 and is attached to a reciprocating pump device (pump) 41 driven by a motor (prime mover) 90. .
In the reciprocating pump device 41, the pressure switch 10 is attached to a connector 72 having a discharge port 73 described later. The pump mounting pipe 11 of the pressure switch 10 is connected to the connector 72.

  Further, the base end portion of the spray hose 1 is attached to the hose connection pipe 12 of the pressure switch 10. A nozzle device 2 is attached to the tip of the spray hose 1. The nozzle device 2 includes a nozzle grip 3 for grasping when the nozzle device 2 is operated by hand, a nozzle pipe 4 extending forward from the nozzle grip 3, and the nozzle grip 3 between the nozzle grip 3 and the nozzle pipe 4. The nozzle 6 is provided for connecting the nozzle grip 3 and the nozzle pipe 4 and switching between spraying and spraying stop at the nozzle 5 provided at the tip of the nozzle pipe 4, and the nozzle for spraying the discharged liquid 5.

The valve 6 switches the spray hose 1 between an open state and a closed state, and when the valve 6 is opened with the motor 90 activated and the reciprocating pump device 41 operating, the reciprocating pump device 41 The liquid discharged from the liquid reaches the nozzle 5 through the spray hose 1 and is sprayed. When the valve 6 is closed, the liquid flow path is closed on the tip side of the spray hose 1 and spraying is stopped.
The pressure switch 10 of this example is connected in series to the power supply of the motor 90, and controls on / off of the motor 90, that is, start and stop.

In the pressure switch 10, the hydraulic pressure inside the pressure switch 10 of the reciprocating pump device 41 rises by closing the valve 6 while the motor 90 is operating, and is relatively higher than the spray pressure at the time of spraying. It becomes the sealing pressure.
Then, the pressure switch 10 is activated and the motor 90 is turned off (stopped). At this time, in the reciprocating pump device 41, a later-described suction valve 81, pressure regulating valve 70, discharge valves 61, 61 and the like are closed, so that the valve 6 is sealed from the reciprocating pump device 41 (discharge port 73). A relatively high sealing pressure is maintained.

Further, when the valve 6 is opened in this state, the hydraulic pressure is released from the opened nozzle 5 side, the hydraulic pressure in the pressure switch 10 becomes low, and a predetermined relative pressure from the relatively high sealed pressure. When the pressure becomes low, the pressure switch 10 is activated to start the motor 90 of the reciprocating pump device 41.
Thereby, the discharge side of the reciprocating pump device 41 becomes the spray pressure, and the liquid is sprayed from the nozzle 5.

As shown in FIG. 2, the pressure switch 10 acting in this way has a casing 13 whose main body is substantially cylindrical and having an internal space, and a manifold which is connected to the casing 13 and is generally cylindrical and has an internal space. 14. Further, the above-described pump attachment pipe 11 is attached to the casing 13, and the above-described hose connection pipe 12 is attached to the manifold 14.
Further, as shown in FIG. 3, the internal space of the casing 13 and the internal space of the manifold 14 become an integrated space (predetermined space) in a state where the casing 13 and the manifold 14 are connected, and a piston (switch An operation member 16 is disposed. In addition, a diaphragm (pressure receiving member) 15 that is a donut-shaped thin plate is disposed at a joint portion between the casing 13 and the manifold 14 with its outer peripheral portion sandwiched therebetween. In addition, a microswitch (switch) 17 is disposed at the front end portion of the casing 13 opposite to the rear end portion to which the manifold 14 is attached.

The casing 13 is formed in a substantially cylindrical shape having an internal space in which the piston 16 is disposed inside the main body. And the attachment cylinder part 18 to which the said pump attachment pipe 11 is fixed is formed in the upper side so that it may orthogonally cross the internal space in the said cylindrical main-body part. And in the attachment cylinder part 18, the screw | thread is cut into the inside and it is set as the screw hole.
On the other hand, the pump mounting tube 11 is formed in a cylindrical shape and is formed with a hexagonal flange 11a that can be rotated by a spanner at the center in the axial direction.

And the outer peripheral surface below the flange 11a of the pump attachment pipe 11 is a male screw. Further, the portion above the flange 11 a is similarly a male screw, and can be attached to the reciprocating pump device 41 by being screwed into the cylindrical connector 72 of the reciprocating pump device 41.
Such a male screw portion below the flange 11 a of the pump attachment pipe 11 is screwed into the attachment cylinder portion 18, and the pump attachment pipe 11 is fastened to the attachment cylinder portion 18. Moreover, the internal space of the said mounting cylinder part 18 and the internal space of the substantially cylindrical casing 13 are in the state mutually connected. The internal space on the main body side of the casing 13 is disposed so as to extend in the horizontal direction, the internal space of the mounting tube portion 18 is disposed so as to extend in the vertical direction, and the internal spaces communicating with each other are inverted T-shaped. It is made into a shape.

Further, the internal space on the main body side of the casing 13 is opened circularly on the rear end side to which the manifold 14 is attached. In addition, the internal space on the main body side of the casing 13 is also opened on the front end side to which the microswitch 17 is attached, but the opening is a circular opening 23 having a smaller diameter than the rear end side opening.
In addition, a microswitch holding portion 19 that holds the microswitch 17 is provided on the front side of the small circular opening 23 of the casing 13. In addition, the microswitch holding unit 19 holds the microswitch 17 between the upper and lower plates. The microswitch 17 is a push button switch having a push button 17a that is turned on when pressed and is returned by biasing means such as a spring when released. Then, as will be described later, the push button 17a is pushed by the piston pin 20 of the piston 16 moved forward to turn on the motor 90, and when the piston 16 moves backward and leaves the push button 17a, the motor 90 is turned off. Yes.

  A piston 16 whose axial direction is aligned with the axial direction of the substantially cylindrical casing 13 is disposed in the internal space of the main body of the casing 13. The piston 16 includes a cylindrical main body 21, a cylindrical piston tip 22 formed on the front side thereof, a piston pin 20 in a state of being inserted into the cylindrical piston tip 22 and fixed, And a diameter-expanded portion 25 having a diameter larger than that of the main body 21 on the rear end side of the main body 21. A through hole (cylindrical internal space) along the axial direction is formed in a portion from the piston tip 22 to the enlarged diameter portion 25 via the main body 21.

  Of this through hole, the piston tip portion 22 is closed by inserting the piston pin 20, but the through hole that opens from the main body portion 21 to the rear end of the enlarged diameter portion 25 is reciprocating. It is the piston first passage 24 through which the liquid discharged from the pump device 41 flows. Further, in the main body 21, a piston second passage 26 is provided as a through hole orthogonal to the through hole along the axial direction of the piston 16, and the piston second passage 26 is orthogonal to the piston first passage 24. It communicates in a state.

  Here, the liquid discharged from the discharge port 73 of the reciprocating pump device 41 flows into the casing 13 through the pump attachment pipe 11, and passes through the attachment cylinder portion 18 to which the pump attachment pipe 11 is attached. It flows into the internal space of the cylindrical main body portion 21 communicating with the cylindrical portion 18. Then, the liquid that has flowed into the main body 21 flows into the piston 16 from the piston second passage 26 that vertically penetrates the piston 16, and passes through the piston first passage 24 from the piston second passage 26 to the rear end of the piston 16. It is supposed to flow out of.

Further, the enlarged diameter portion 25 after the main body portion 21 of the piston 16 is accommodated in the manifold 14 after the casing 13.
Further, the enlarged diameter portion 25 is disposed on the manifold 14 side from the diaphragm fixed by sandwiching the entire outer peripheral portion at the joint portion of the casing 13 and the manifold 14. Further, the outer peripheral surface of the main body portion 21 of the piston 16 is threaded to form a male screw. A lock nut 28 is screwed to the male screw, and an inner peripheral portion of the diaphragm 15 in a state where a hole is formed in the center portion and the piston 16 penetrates between the enlarged diameter portion 25 and the lock nut 28 is sandwiched. The piston 16 is fixed to the diaphragm 15 by the lock nut 28.

That is, the annular outer periphery of the diaphragm 15 is joined to the manifold 14 and the casing 13 which are joined to each other in a state where the annular outer periphery is sandwiched between the cylindrical casing 13 and the same cylindrical casing 13. The inner peripheral portion is joined in a state of being fastened by the enlarged diameter portion 25 and the retaining nut 28.
Therefore, the internal space communicating with the casing 13 and the manifold 14 is the A space (one space) 29 that is the internal space of the casing 13 by the diaphragm 15 on the outer peripheral side of the piston 16 and the B that is the internal space on the manifold 14 side. The chamber (the other space) 30 is divided into two spaces.

  The A chamber 29 and the B chamber 30 are separated by the diaphragm 15, and pass through the piston second passage 26 and the piston first passage 24 of the piston 16 extending from the A chamber 29 to the B chamber 30. The liquid discharged from the reciprocating pump device 41 can flow between the A chamber 29 and the B chamber 30.

Further, the diaphragm 15 can be bent toward the A chamber side or to the B chamber side with respect to the outer peripheral portion due to the pressure difference between the partitioned A chamber and the B chamber. The piston 16 can be moved forward and backward along the axial direction. When force is applied to the piston 16 instead of the diaphragm 15 due to a compression coil spring (biasing means) 36 described later or an increase in the hydraulic pressure of the pressure switch 10 as a whole, the diaphragm 15 moves the piston 16 along the axial direction. The piston 16 is movable along the axial direction.
The diaphragm is, for example, a synthetic resin (containing a rubber or a thin plate (film) made of metal or the like) and is bent so that the inner peripheral portion can move back and forth with respect to the outer peripheral portion as described above.

  The opening of the piston first passage 24 is formed on the rear end surface of the enlarged diameter portion 25 of the piston 16, and the opening serves as a valve seat 39a of a valve 39 (pressure loss means) as pressure loss means. The periphery of the opening is a concave surface. Further, a valve body 39b is disposed to face the valve seat 39a. The valve body 39b is disposed behind the rear end surface of the enlarged diameter portion 25 of the piston 16, and can be contacted and separated from the valve seat 39a. Further, after the valve body 39b, a compression coil spring (valve body biasing means) 39c for pressure loss means is arranged in a state supported by the hose connection pipe 12 as described later, and the valve body 39b is attached to the valve body 39b. The valve seat 39a is biased by a compression coil spring 39c as a biasing means.

  Further, the valve seat surface of the valve seat 39a that contacts the valve body 39b is a circular concave surface centering on the opening of the piston first passage 24, and the valve seat surface extends along the radial direction of the circle. A groove 39d is formed. That is, in a state where the valve body 39b is in contact with the valve seat 39a, the valve seat 39a is communicated with the piston first passage 24 closed by the valve body 39b and the B chamber 30 as the internal space of the manifold 14. Even if the valve body 39b comes into contact with the valve seat 39a, the flow of the liquid cannot be completely stopped at the valve 39 and the flow rate is limited. As a result, when a difference in hydraulic pressure occurs between the A chamber 29 and the B chamber 30 with the valve 39 closed, this hydraulic pressure difference is immediately attenuated to 0. Converge to.

  In the A chamber 29 of the casing 13, the portion on the manifold 14 side has the largest diameter, which is slightly larger than the outer diameter of the locking nut 28 that is substantially the same diameter as the enlarged diameter portion 25 at the rear end portion of the piston 16. It has a large diameter. The central portion before the rear end portion of the A chamber 29 has an inner diameter smaller than the outer diameter of the retaining nut 28. The movement of the locking nut 28 to the front side is regulated by the step between the rear end portion and the central portion of the A chamber 29, and the movement of the piston 16 to which the locking nut 28 is fastened is moved. The range is up to this boundary. This position becomes the top dead center of the piston 61, which is a second position with respect to the first position described later.

  And the piston tip part 22 of the front side is arrange | positioned from the piston 2nd channel | path 26 of the main-body part 21 of the piston 16 in the center part of the A chamber 29, and also it will be in the state which the piston pin 20 extended from the piston tip part 22. The tip of the piston pin 20 is slightly protruding from the small-diameter opening 23 at the tip of the casing 13 described above. In FIG. 3, the piston 16 is in a state of being retracted to the rearmost side (first position).

  A seal housing portion 31 having a diameter slightly smaller than that of the A chamber is provided on the front side of the A chamber 29, and the seal 27 is fixed to the seal housing portion 31. The seal 27 is in a state in which the outer peripheral surface is in contact with the inner wall of the seal housing portion 31, and a hole through which the piston pin 20 passes is formed in the center portion, and the inner peripheral side of the seal 27 is a piston at the hole portion. The pin 20 is in contact with the outer periphery of the pin 20 and stopped. The piston pin 20 slides on the inner peripheral member of the seal 27.

A lubricating oil chamber 32 having a smaller diameter than that of the seal housing portion 31 is provided at the tip of the seal housing portion 31 of the casing 13. The lubricating oil chamber 32 communicates with an inlet 33 that opens to the upper side of the outer peripheral surface of the casing 13, so that the lubricating oil can be supplied to the lubricating oil chamber 32.
The lubricating oil in the lubricating oil chamber 32 reduces the sliding resistance when the seal 27 and the piston pin 20 slide.
The small-diameter opening 23 is formed at the tip of the injection port 33, and the opening 23 has a smaller diameter than the lubricating oil chamber 32. And as above-mentioned, the front-end | tip part of the piston pin 20 has penetrated this opening part 23. As shown in FIG.

In addition, an annular washer 35 is arranged on the A chamber side of the step portion that becomes the boundary between the above-described A chamber 29 and the seal housing portion 31 having a smaller diameter, and the piston pin 20 penetrates the washer 35. It has become.
A compression coil spring 36 is disposed between the locking nut 28 and the washer 35. The compression coil spring 36 urges the piston 16 to the B chamber 30 side, that is, the side where the piston pin 20 is separated from the push button 17 a of the micro switch 17 via the lock nut 28. That is, the piston 16 is urged so as to retract from the second position to the first position.

The internal space of the cylindrical manifold 14 is open to each of a front end side to which the casing 13 is connected and a rear end side to which the hose connection pipe 12 is connected. The diameter of the opening on the front end side of the manifold 14 is substantially equal to the diameter of the opening on the rear end side of the casing 13.
And the connection part of the manifold 14 and the casing 13 is made into substantially square shape, respectively, and the manifold 14 and the casing 13 are fastened with the screw | screw in each of the four corner parts.

The B chamber 30 which is the internal space of the manifold 14 is configured such that a piston storage portion 37 on the tip side of the manifold 14 and an attachment cylinder portion 38 for attaching the hose connection pipe 12 communicate in the axial direction. .
The piston housing portion 37 has an inner diameter slightly wider than the outer diameter of the enlarged diameter portion 25 at the rear end portion of the piston 16.
Further, the mounting cylinder portion 38 has a narrower inner diameter than the piston storage portion 37, and a step is formed at a boundary portion between the inner peripheral surface of the piston storage portion 37 and the inner peripheral surface of the mounting cylinder portion 38. Then, the outer peripheral portion of the rear end surface of the enlarged diameter portion 25 abuts on this step surface, so that the movement range is restricted when the piston 16 is retracted. The position where the piston 16 is retracted is the bottom dead center, and this bottom dead center is the first position.

  Further, the inner peripheral surface of the mounting cylinder portion 38 is threaded to form a screw hole, and the hose connection pipe 12 is screwed into the screw hole and fastened. Further, the hose connection pipe 12 is formed in a cylindrical shape and a hexagonal flange 12a is formed at the center thereof. Then, a screw is cut on the outer peripheral surface below the flange 12 a of the hose connection pipe 12 to form a male screw, and is screwed into the mounting tube portion 38 to be fastened.

  The inside of the portion of the hose connection pipe 12 to be inserted into the attachment tube portion 38 has a diameter larger than the tip side on the base end side, and a valve 39 serving as the pressure loss means is disposed on the large diameter portion. The valve body 39b is arranged. In addition, a step is formed in the inner space adjacent to the base end portion, which is smaller in diameter than the inner diameter of the base end portion, and in the inner space and the boundary surface of the base end portion, and the outer peripheral portion of the rear end surface of the valve body 39b is formed in this step. Can be contacted, and the moving range of the valve body 39b is regulated by the valve seat 39a and this step.

Moreover, a plurality of openings 12b communicating from the internal space to the outside on the outer peripheral surface side are formed immediately on the front side of the portion where the valve body 39b is arranged inside the base end portion of the hose connection pipe 12, A sufficient flow rate can be secured even in a state where most of the opening on the base end side of the hose connection pipe 12 is closed by the valve body 39b. Further, the outer periphery of the base end portion of the hose connecting pipe 12 is not threaded, and the opening 12b is provided in this portion. The inner diameter of the mounting tube portion 38 is larger than the outer diameter of the base end portion of the hose connection tube 12, and there is a gap between the outer peripheral surface of the hose connection tube 12 and the inner peripheral surface of the mounting tube portion 38. This also allows the liquid to flow sufficiently.
Further, there is a step on the front side of the opening 12b of the hose connection pipe 12 due to the decrease in diameter, and the compression coil spring 39c described above is disposed between the step and the valve body 39b.

Next, the configuration of the reciprocating pump device 41 to which such a pressure switch 10 is attached will be described. As shown in FIGS. 4 and 5, two reciprocating pumps 42 and 42 are provided on the same axis and facing in opposite directions.
The reciprocating pump device 41 has a motor 90 as its drive source. In this example, the motor 90 has a substantially cylindrical outer shape, and the direction along the motor shaft 91 is the longitudinal direction. Yes. A substantially square flange portion 92 is provided on the end surface on the side from which the motor shaft 91 protrudes.

The reciprocating pump device 41 includes a crankcase 43 and manifolds 44 and 45 attached to the left and right ends of the crankcase 43, respectively.
The crankcase 43 includes a flange portion 46 having a substantially square plate shape at the lower end and a circular opening inside. The flange portion 46 has substantially the same shape as the flange portion 92 of the motor 90 formed on the distal end side where the motor shaft 91 of the motor 90 is provided, and is arranged so as to overlap the flange portion 92 of the motor 90. Thus, the motor 90 and the crankcase 43 of the reciprocating pump device 41 are joined together.

  A cylindrical portion 47 having an internal space communicating with the opening of the flange portion 46 is integrally attached to the upper side of the flange portion 46 of the crankcase 43. The cylindrical portion 47 is arranged coaxially with the motor shaft 91 of the motor 90 attached to the crankcase 43, and the motor shaft 91 and the bias attached to the motor shaft 91 are installed in the space 48 inside thereof. The attachment cylinder part 52 of the lead cam 51 is in a state of being housed in the center part.

Formed on the upper side of the cylindrical portion 47 of the crankcase 43 is a bearing support portion 50 having a disk-like space in which a bearing 49 for rotatably supporting a mounting cylinder portion 52 described later of the eccentric cam 51 is fixed. ing.
A space 57 in which the cam portion 53 of the eccentric cam 51 and the connecting portion 55 formed corresponding to the pair of piston rods 54 and 54 are connected via a bearing 56 on the upper side of the bearing support portion 50. Is formed in the crankcase 43. In addition, the axial direction of the cylinder part 58 corresponds with the motor shaft 91 direction.

  Cylinder cylindrical portions 60 and 60 into which cylinders 59 and 59 of the reciprocating pumps 42 and 42 are respectively inserted are formed on the left and right sides of the cylinder portion 58 of the crankcase 43 in a state where the base end portion is in communication with the cylinder portion 58. Has been. In the crankcase 43, the cylinder cylinders 60 and 60 have their tip portions facing away from each other in an open state in the crankcase 43, and communicate with a merging and discharging passage 63 described later by the manifolds 44 and 45. It is blocked in the state.

The crankcase 43 is provided with left and right discharge valves 61 and 61 for discharging liquid from the left and right reciprocating pumps 42 and 42, and the liquid discharged from these discharge valves 61 and 61 is supplied to a final discharge passage described later. A merging / discharging passage 63 leading to 62 is provided.
The merging / discharging passage 63 is provided on a straight line in parallel with the pair of cylinder cylindrical portions 60 and 60 and the piston rods 54 and 54, and is provided at a position overlapping each other in the direction of the motor shaft 91. That is, the confluence discharge passage 63 is provided side by side with the piston rods 54 and 54. Further, in the crankcase 43, a portion constituting the cylinder cylindrical portions 60, 60 and the merging / discharging passage 63 and a portion constituting a later-described branch suction passage 83 are integrally formed.

The front end position of the left cylinder cylindrical portion 60 and the left end position of the merging / discharging passage 63 are arranged in one plane on the left side, and the front end position of the right cylinder cylindrical portion 60 and the right end of the merging / discharging passage 63 are arranged. The left and right planes are parallel to each other. The merged discharge passage 63 is formed on the opposite side of the motor 90 of the pair of cylinder cylindrical portions 60, 60.
The above-described discharge valves 61 and 61 are accommodated in the left and right end portions of the merging / discharging passage 63, and the discharge valve 61 is located at the center side of the discharge valve body 64 of the discharge valve 61 in the left and right end portions of the merging / discharging passage 63. A plurality of protrusions 67 are formed in a portion where the compression coil spring 66 for applying an urging force for pressing the body 64 against the discharge valve seat 65 on the end side thereof is disposed.

Further, the left and right end portions where the discharge valves 61, 61 having the compression coil springs 66 of the merging discharge passage 63 are arranged are wider in diameter than the central portion. A plurality of ridges 67 are formed at the portion where the discharge valve bodies 64 and 64 and the compression coil spring 66 on the center side of the discharge valve bodies 64 and 64 are arranged.
The ridges 67 are arranged on the inner peripheral surface of the merging / discharging passage 63 along the axial direction of the merging / discharging passage, and are arranged at equal intervals in the circumferential direction. Further, the ridges 67 are all the same shape, and the positions along the axial direction of the merged discharge passage 63 are the same.

Further, the protrusion 67 is higher on the center side (rear side) than on the front end side which is the end side of the merged discharge passage 63. In other words, the protrusions 67 and 67 have a stepped surface 68 because the rear side is thicker from the inner periphery of the merged discharge passage 63 with respect to the front side. Further, the upper surface of the protrusion 67 is an arc surface centered on the central axis of the merged discharge passage 63. And the discharge valve seat 65 is arrange | positioned ahead of the front end surface of the protrusion 67, and the movement to the center side of the discharge valve seat 65 is controlled. Further, the discharge valve body 64 is disposed between the tip surface of the protrusion 67 and the step surface 68, and the movement of the discharge valve body 64 toward the center is restricted by the step surface 68 of the protrusion 67.
Further, the discharge valve seat 65 is pressed by the manifolds 44 and 45 attached to the left and right end surfaces of the crankcase 43 so that the movement to the outside of the crankcase 43 is restricted.

Further, the liquid discharged from the discharge valve 61 passes between the protrusions 67, and the outer periphery of the discharge valve body 64 from the hole of the discharge valve seat 65 when flowing into the merged discharge passage 63. The liquid in which the flow is disturbed through the side can be rectified, and the liquid can smoothly flow into the merged discharge passage 63.
A pressure regulating passage 69 communicating with a pressure regulating valve 70 described later is connected to a central portion of the merged discharge passage 63, that is, a portion intersecting with an extension line of the motor shaft 91.

The pressure adjusting passage 69 extends along the axial direction of the motor shaft 91 and is orthogonal to the merging / discharging passage 63. In this example, the pressure adjusting passage 69 is in a state of extending to the front side with respect to the merged discharge passage 63 extending to the left and right.
Further, the pressure adjusting passage 69 is opened at the front end side of the reciprocating pump device 41, and a pressure adjusting unit 100 having the pressure adjusting valve 70 is connected to the front end portions of the front, rear, left and right sides of the reciprocating pump device 41. It has come to be. The pressure adjustment unit 100 is fixed to the crankcase 43 with screws 101.

Further, the final discharge passage 62 is connected to the confluence discharge passage 63 and the pressure adjustment passage 69 with the center slightly shifted forward with respect to the center of the connection portion between the confluence discharge passage 63 and the pressure adjustment passage 69. Yes. The final discharge passage 62 extends at a right angle to the confluence discharge passage 63 and the pressure adjusting passage 69 along the motor shaft 91. In this example, the extending direction of the final discharge passage 62 is the lower side. .
A connecting cylindrical portion 71 having a diameter larger than that of the final discharge passage 62 is provided below the final discharge passage 62. A connector 72 is fitted and fixed to the inside of the connection cylindrical portion 71, and an opening at the lower end of the connector 72 serves as a discharge port 73. The connector 72 is connected to the pump mounting pipe 11 of the pressure switch 10 described above.

Further, the air in a state where the center is located before the center of the merging discharge passage 63 and after the center of the final discharging passage 62 at a portion where the merging discharge passage 63, the pressure adjusting passage 69 and the final discharge passage 62 are connected and joined to each other. An extraction passage 74 is formed. Further, the air vent passage 74 is orthogonal to the merging discharge passage 63 and the pressure adjusting passage 69 and is parallel to the final discharge passage 62, but the final discharge passage 62 extends downward from the merging discharge passage 63. On the other hand, the air vent passage 74 extends upward.
The air vent passage 74 is connected to an air vent cylinder portion 75 having a larger diameter than the air vent passage 74, and an air vent valve 76 is provided in the air vent cylinder portion 75.

  Also. In the upper part of the air bleed cylindrical portion 75, an air discharge passage 80 for sending the air discharged by the air bleed valve 76 and the liquid discharged together with the air to the pressure adjusting unit 100 is perpendicular to the air bleed passage 74. Along the front side. The air discharge passage 80 is open on the mounting surface side of the crankcase 43 where the pressure adjustment unit 100 is attached, and the air discharge passage 80 communicates with a communication passage 102 of the pressure adjustment unit 100 described later. It has become. As will be described later, the communication passage 102 communicates with a spillway 103 which will be described later, so that the liquid discharged when the air is vented can flow to the spillway 103.

Water from the suction port 82 is caused to flow into the water suction valves 81, 81 of the left and right reciprocating pumps 42, 42 at the height position between the pair of cylinder cylindrical portions 60, 60 and the confluence discharge passage 63. A branch suction passage 83 is provided. The branch suction passage 83 is formed in parallel with the cylinder cylindrical portions 60 and 60 and the merging / discharging passage 63 which are parallel to each other. That is, the branch intake passage 83 is provided side by side with the piston rods 54 and 54.
Further, as described above, the end portions of the branch intake passage 83 are also arranged on the left and right planes parallel to each other where the end portions of the confluence discharge passage 63 and the cylinder cylindrical portions 60 and 60 are arranged.

That is, the left end opening of the confluence discharge passage 63, the tip end opening of the left cylinder cylindrical portion 60, and the left end opening of the branch suction passage 83 are arranged in one left plane, and one right plane is arranged. Inside, a right end opening of the confluence discharge passage 63, a tip opening of the right cylinder portion 60, and a right end opening of the branch suction passage 83 are disposed.
The left and right portions of the crankcase 43 corresponding to the left and right planes described above are the left end surface and the right end surface, and the left manifold 45 is fixed to the left end surface where the openings are arranged with screws 45a,. The right manifold 44 is fixed to the right end surface with screws 44a.

  The left and right end portions of the branch suction passage 83 are provided with suction communication passages 93 and 93 for communicating the branch suction passage 83 with the positions corresponding to the water suction valves 81 of the left and right cylinder cylindrical portions 60 and 60. . The left end portion of the branch suction passage 83 is communicated with a suction port 82 provided in the manifold 45 in a left manifold 45 described later.

  The left and right manifolds 44 and 45 have the same inner diameter as that of the left and right cylinder cylindrical portions 60 and 60. When the manifolds 44 and 45 are fixed to the crankcase 43, Concluded discharge opened at the mounting surface of the crankcase 43 to which the concave portions 84 and 84 arranged coaxially with and communicate with the cylindrical portion 60, the bottom portion (tip portion) of the concave portion 84, and the manifolds 44 and 45 are mounted. Discharge valve communication passages 85 and 85 communicating with the opening of the passage 63 are provided.

  The right manifold 44 is provided with a blocking portion 86 that closes the right end opening of the branch suction passage 83 on the mounting surface of the manifold 44 of the crankcase 43. Further, a suction passage 87 communicating with the left end opening of the branch suction passage 83 is formed in the left manifold 45, and the suction passage 87 is arranged in the same direction as the branch suction passage 83 from the motor shaft 91. It is in a state of being bent so as to face the rear side along the axial direction, a portion facing the rear side is formed in a tubular shape, and a tip end portion is formed as an inlet port 82, so that a hose can be connected. The hose is connected to, for example, a tank containing a liquid to be discharged. The motor 90 is formed long along the axial direction of the motor shaft 91, and the length in the direction along the motor shaft 91 is longer than the diameter of the cylindrical portion. Therefore, the portion of the suction passage 87 along the axial direction of the motor shaft 91 is along the longitudinal direction of the motor 90.

The pair of reciprocating pumps 42 and 42 are supported by the crankcase 43 and the manifolds 44 and 45 as described above.
And each reciprocating pump 42 and 42 is formed in the same structure except the direction being reverse. In each of the reciprocating pumps 42, 42, a seal packing 88, a seal packing presser 89, and a cylinder pipe 94 are arranged in order from the center along the inner peripheral surface in the cylinder cylindrical portions 60, 60. The piston rod 54 is disposed so as to be movable left and right inside the seal packing 88, the seal packing press 89, and the cylinder pipe 94.

  The seal packing 88 has an inner peripheral surface that contacts the outer peripheral surface of the piston rod 54, and the piston rod 54 slides with respect to the seal packing 88. This prevents the liquid to be discharged from the cylinders 59 and 59 side from leaking from the seal packing 88 to the center side. The seal packing 88 is fixed to the inner peripheral surfaces of the cylinder cylindrical portions 60, 60 by a step formed along the circumferential direction and a seal packing presser 89.

Further, a cylinder pipe 94 is arranged on the end side of the seal packing presser 89 so as to be continuous with the seal packing presser 89. The seal packing presser 89 and the cylinder pipe 94 are arranged coaxially and have the same diameter. The seal packing presser 89 and the cylinder pipe 94 constitute a cylinder 59.
The cylinder pipe 94 is attached to the cylinder cylindrical portion 60 so as to protrude from the cylinder cylindrical portion 60 of the crankcase 43, and the front side is inserted into the recesses 84 and 84 of the manifolds 44 and 45. The cylinder of the reciprocating pump 42 is formed from the crankcase 43 to the manifolds 44 and 45. The cylinder pipe 94, the seal packing presser 89, and the seal packing 88 are pressed by the manifolds 44 and 45 so that the outward movement is restricted.

In the cylinder 59, a water absorption valve 81 provided at the tip of the piston rods 54, 54 is arranged 81. The water absorption valve 81 includes a water absorption valve seat 95 fixed by a screw 99 screwed to the tip end surface of the piston rod 54, a collar 96, and a stopper 97, and the collar 96 is interposed between the water absorption valve seat 95 and the stopper 97. The water absorption valve body 98 in a state where is inserted is disposed.
Then, the water absorption valve seat 95, the collar 96, and the stopper 97 are arranged in this order from the tip of the piston rod 54 toward the front side (outside), and as described above, the water absorption valve seat 95 and the outer side of the collar 96. A water absorption valve body 98 is disposed between the stopper 97 and the stopper 97.

Further, the screw 99 penetrates the stopper 97 and the cylindrical collar 96, and further penetrates the water absorption valve seat 95 and is fastened to the piston rod 54.
A collar 96 is disposed between the water absorption valve seat 95 and the stopper 97, and the water absorption valve seat 95 and the stopper 97 are spaced apart by a length along the axial direction of the collar 96.
The water absorption valve element 98 in which the collar 96 is inserted has a substantially cylindrical structure, and the inner diameter thereof is larger than the outer diameter of the collar 96 inserted into the water absorption valve element 98, and the water absorption valve element. An interval is formed between the inner peripheral surface of 98 and the outer peripheral surface of the collar 96 so that the liquid to be discharged can flow.

  Further, the water absorption valve body 98 has a piston packing that contacts and slides on the outer peripheral portion of the inner peripheral surface of the cylinder pipe 94, and the water absorption valve body 98 is formed on the inner peripheral surface of the cylinder pipe 94. The cylinder pipe 94 is restricted to move along the axial direction. And since the water absorption valve body 98 and the collar 96 are arrange | positioned coaxially, between the inner peripheral surface of the water absorption valve body 98 and the outer peripheral surface of the collar 96, the cyclic | annular space | gap over the perimeter is always formed. Has been.

  The distance between the water-absorbing valve seat 95 and the stopper 97, that is, the length of the collar 96 is longer than the length along the axial direction of the water-absorbing valve body 98. The rear end side (center side) end surface is in contact with the seat 95 and the front end side (outer side) end surface is separated from the stopper 97, and conversely, the rear end side (center side) with respect to the water absorbing valve seat 95. It is possible to move between the state where the end surface is separated and the end surface (outer side) is in contact with the stopper 97.

  Further, in a state where the water absorption valve body 98 is in contact with the water absorption valve seat 95, the liquid does not flow into the portion composed of the water absorption valve body 98 and the water absorption valve seat 95, and the water absorption valve body 98 and the stopper 97 are in contact. In this state, the through-hole provided in the stopper 97 communicates with the inner peripheral side of the water-absorbing valve body 98, and the water-absorbing valve body 98 and the water-absorbing valve seat 95 are separated from each other. The liquid can flow in between 95 and can flow out from the through hole of the stopper 97.

The piston rods 54 and 54 are driven by the motor 90, and the eccentric cam 51 is attached to the motor shaft 91 of the motor 90.
The eccentric cam 51 includes an attachment tube portion 52 to which the motor shaft 91 is inserted and fixed, and a cam portion 53 that is provided on the front side of the attachment tube portion 52 and functions as an actual cam.
The mounting cylinder portion 52 has an inner diameter substantially the same as the outer diameter of the motor shaft 91 and includes a screw hole 105 extending from the outer peripheral surface to the inner peripheral surface. Further, the motor shaft 91 includes a plane along the axial direction at a portion corresponding to the screw hole 105 when the mounting cylinder portion 52 is set on the motor shaft 91. Then, by screwing and tightening a screw shaft whose outer peripheral surface is a male screw into the screw hole 105, the mounting cylinder portion 52 of the eccentric cam 51 can be rotated integrally with the motor shaft 91 with respect to the motor shaft 91. Can be fixed.

And the attachment cylinder part 52 is rotatably supported by the above-mentioned bearing 49.
The cam portion 53 is provided integrally with the attachment tube portion 52 on the front side of the attachment tube portion 52, and rotates together with the attachment tube portion 52 as the motor shaft 91 rotates.
Moreover, although the cam part 53 is formed in a column shape, the center of the column and the center of rotation are shifted. That is, the cam portion 53 is not coaxially arranged with respect to the motor shaft 91, and the center of the cam portion 53 is eccentric with respect to the center of the motor shaft 91.

Therefore, when the motor shaft 91 is rotated, the outer peripheral portion of the cam portion 53 is in a state of rotating while moving back and forth and left and right.
The cam portion 53 is in a state of being supported by the bearing 56, but the bearing 56 moves back and forth and right and left without rotating corresponding to the movement of the rotating cam portion back and forth and left and right.

In addition, the two piston rods 54 and 54 are in a state where the rear end side, which is the center side of the reciprocating pump device 41, is integrally continuous, and the two piston rods 54 and 54 become one member. Yes. And the connection part 55 which connects a pair of piston rods 54 and 54 is in the state by which the recessed part was formed in the rear side of the connection part 55 by forming thickness thinner than the piston rods 54 and 54.
The bearing 56 is held in the concave portion of the connecting portion 55 so as to be movable up and down, and the piston rods 54 and 54 are moved back and forth in the axial direction along with the movement of the eccentric cam 51. It has become.

  Further, the above-described pressure adjusting unit 100 is provided at the tip of the crankcase 43. The pressure regulating unit 100 includes a pressure regulating case 106 in which a pressure regulating valve 70 is built, a pressure regulating valve seat 107 fixed in the pressure regulating case, a closed state in contact with the pressure regulating valve seat 107, and a pressure regulating valve seat 107. A pressure regulating valve body 108 that is movable between the separated open states, a coil spring 110 as a biasing means that biases the pressure regulating valve body 108 toward the pressure regulating valve seat 107, and a tip side of the coil spring 110 (a pressure regulating valve body) By adjusting the position on the opposite side of (108), a top 111 for adjusting and adjusting the biasing force of the coil spring 110 and a screw 112 having a hexagonal hole on the tip side of the top 111 are provided.

The pressure regulating case 106 has a cylindrical shape with a main portion having a hole in a portion where the pressure regulating valve seat 107, the pressure regulating valve body 108, and the coil spring 110 are disposed.
A screw hole, which will be described later, is formed in the lid portion at the tip of the pressure regulating case 106. Further, the pressure regulating valve body 108 is separated from the pressure regulating valve seat 107 due to the pressure stronger than the urging force of the coil spring 110 being applied to the portion where the coil spring 110 on the tip side of the pressure regulating valve body 108 is provided. A cylindrical pressure regulating discharge passage 114 is formed to allow water to flow out to the spillway 103 for discharging the liquid that has flowed in based on the pressure valve 70 being in the open state.

Further, on the opposite side of the pressure regulation discharge passage 114, a communication passage 102 is provided, one end of which communicates with the opening of the air discharge passage 80 exposed at the tip end surface of the crankcase 43, and is extended from the air discharge passage 80. The air and liquid are discharged to the spillway 103 side.
The screw 112 is screwed into a screw hole formed in the axial direction of the pressure regulating case 106, and the position of the top 111 is adjusted by rotating the screw 112 to adjust the pressure of the pressure regulating valve 70. It has become. Note that the front end portion to which the screw 112 is screwed is covered with a removable cap 113.
The air vent valve 76 has a spherical air vent body between the bottom of the air vent cylindrical portion 75 having a hole communicating with the air vent passage 74 and the air valve seat 77 having a hole communicating with the air discharge passage 80. 78 is arranged. Further, the inner periphery of the air bleed cylindrical portion 75 is a female screw, and a bolt-shaped plug 79 whose outer periphery is a male screw is screwed into the female screw, and the air bleed valve seat 77 is fixed by the plug 79. It is in the state.

  In this state, a space slightly longer than the diameter of the air bleeder 78 is provided between the air bleed cylindrical part 75, the bottom, and the air bleeder seat 77. A state where the hole communicating with the air discharge passage 80 of the air vent valve seat 77 is opened is opened. Further, when the normal reciprocating pump device 41 is not operated, the air valve seat 77 and the plug 79 are located above the air valve body 78, and the air valve body 78 is separated from the air valve seat 77 by gravity, and the air vent cylinder portion 75. It is in the state which contacted the bottom of. A groove or a ridge is formed around the hole communicating with the air vent passage 74 at the bottom, and the liquid and gas flow out from the air vent passage 74 even if the air vent valve 78 is disposed in the hole shape. It is possible.

  When the reciprocating pump device 41 is activated, for example, when air is present in the cylinders 59, 59, the discharge pressure of the liquid from the left and right reciprocating pumps 42, 42 does not increase, and the air vent valve 76 The air vent 78 is on the bottom and is open. In this state, air can be extracted from the reciprocating pumps 42 and 42 via the air vent valve 76. Further, since the air vent valve 76 is in an open state, the internal pressure in the reciprocating pumps 42 and 42 including the merging / discharging passage 63 does not increase even if the pressure regulating valve 70 is present, and the air can be easily vented.

  Here, when the air in the reciprocating pumps 42, 42 becomes high, the discharge pressure of the liquid from the reciprocating pumps 42, 42 to the confluence discharge passage 63 increases, and the liquid containing almost no air passes through the confluence discharge passage 63. The air flows from the air vent passage 74 into the air vent cylinder portion 75. With this liquid, the air valve body 78 is pressed against the air valve seat 77 to close the hole of the air valve seat 77. As a result, the air vent valve 76 is closed, and the internal pressure of the reciprocating pumps 42 and 42 rises in a range regulated by the pressure regulating valve 70, and the air vent body 78 is pressed against the air vent valve seat 77 by this pressure, and the reciprocating pump device. During the operation of 41, the air vent valve 76 is always closed.

When the reciprocating pump device 41 is stopped, there is no internal pressure acting on the air valve body 78 (when the nozzle is open), the air valve body 78 is separated from the air valve seat 77, and the air valve 76 is opened again. . At this time, since the air valve seat 77 is above the air valve body 78, the air valve body 78 is completely separated from the air valve seat 77 by gravity. Thereby, it is possible to prevent the air valve body 78 from adhering to the air valve seat 77 when not in use.
The air vent valve 76 can be maintained by loosening the hexagonal head of the plug 79 with a spanner or the like and removing the plug 79 from the air vent cylindrical portion 75. However, as described above, the air vent body 78 and the air By preventing the valve seat 77 from sticking, maintenance can be reduced.

  In such a reciprocating pump device 41, in the suction process, the piston rod 54 moves backward toward the center, so that the water absorption valve body 98 moves away from the water absorption valve seat 95 and abuts against the stopper 97. Water is sucked from between the seats 95, and the water flows into the stopper 97 side from between the water absorption valve body 98 and the collar 96. Here, the liquid sucked from the suction port 82 passes from the suction port 82 through the suction passage 87 to the branch suction passage 83, and from the left and right ends of the branch suction passage 83 to the cylinder via the suction communication passages 93 and 93. 59, 59. Further, on the inner peripheral surface side of the cylinder 59, end side openings of the suction communication passages 93, 93 are formed, and water is sucked into the water intake valve 81 from the openings, and the sucked water is ahead of the water intake valve body 98. It can flow out to the side.

  When the piston rod 54 that has become the central side is advanced toward the end side when the suction process is completed, the water absorption valve body 98 comes into contact with the water absorption valve seat 95, and the water absorption valve seat 95 and the water absorption valve body 98 are brought into contact with each other. The space is closed and the water intake valve is closed. When the piston rod 54 moves forward in this state, water on the front side of the water absorption valve body 98 is pushed toward the concave portions 84 and 84 of the manifolds 44 and 45, reaches the discharge valve communication passages 85 and 85 from the concave portions 84 and 84, and is discharged. The valve communication passages 85, 85 reach the confluence discharge passage 63.

  And it reaches the discharge valves 61 and 61 formed at the left and right ends of the merged discharge passage 63. In the discharge valves 61, 61, the discharge valve bodies 64, 64 urged toward the discharge valve seats 65, 65 by the compression coil spring 66 are pushed out from the cylinders 59, 59 to the recesses 84, 84 as described above. The discharge valve bodies 64 and 64 are separated from the discharge valve seats 65 and 65, and the liquid flows into the merged discharge passage 63.

  At this time, protrusions 67 along the axial direction are formed on the inner peripheral surface at the left and right ends of the above-described merged discharge passage 63 where the compression coil spring 66 is formed as described above. As described above, the protrusion 67 passes between the discharge valve seats 65 and 65 and the discharge valve bodies 64 and 64 and flows into the merged discharge passage 63 to rectify the turbulent liquid and smoothly merge and discharge. It flows from the passage 63 into the final discharge passage 62 provided at the center of the merged discharge passage 63. The final discharge passage 62 communicates with the pressure adjusting passage 69 communicating with the pressure adjusting valve 70 as described above, and a liquid discharge load is applied by a hose having a nozzle connected to the discharge port 73. As a result, the pressure applied to the liquid is adjusted.

Further, the final discharge passage 62 communicates with an air vent valve 76. For example, when the reciprocating pump device 41 is activated, the final discharge passage 62 does not increase pressure in the portion of the final discharge passage 62 in a state where air is blown. Thus, the air vent valve 76 is opened.
As a result, air can be released from the air release valve 76, and a liquid containing air is sent from the air discharge passage 80 to the pressure adjustment unit 100, and can flow from the spillway 103.

  According to the above-described reciprocating pump device, the discharge valves 61 and 61 are housed in the left and right end portions in the merged discharge passage 63 instead of the front ends of the cylinders 59 and 59 (outside the crankcase 43). In addition, the pressure regulating valve 70 is provided not on the end of the merged discharge passage 63 but on the opposite side of the motor 90 at the center, and the discharge port 73 is provided not on the end of the merged discharge passage 63 but on the center. Since the air vent valve 76 is also provided in the central portion of the merging / discharging passage 63, the length in the direction along the piston rods 54 and 54 provided side by side in the merging / discharging passage 63 of the reciprocating pump device 41 can be shortened. It is also possible to make the diameter close to 90.

Here, since the discharge port 73 is provided so as to face in a direction orthogonal to both the motor shaft 91 and the piston rods 54 and 54, even if the hose is connected to the discharge port 73, it follows the piston rods 54 and 54. Does not require space in the length direction.
Further, since the suction port 82 is also connected to the hose along the longitudinal direction of the motor 90, that is, the direction of the motor shaft 91, a space for connecting the hose along the longitudinal direction of the piston rod 54.54. There is no need to take large.

Further, the spill port 103 of the pressure regulating valve 70 can be connected to a hose in a direction perpendicular to the piston rods 54 and 54 at the central portion of the merging / discharging passage 63, and piping space is provided along the direction of the piston rods 54 and 54. There is no need to secure. Further, the spillage port 103 also serves as the discharge port of the air vent valve 76, and the piping space can be made efficient.
Further, since the discharge port 73 and the spillage port 103 are disposed in the central portion of the merged discharge passage 63, that is, the central portion of the reciprocating pump device 41, the hose connected to the discharge port 73 and the spillway port 103 can be freely operated. The degree is great. That is, if it is provided at the left or right end of the reciprocating pump device 41, the handling of the hose to the opposite end may be limited.

  Further, by providing the left and right discharge valves 61 in the merged discharge passage 63, the distance between the left and right reciprocating pumps 42, 42 is shortened, and based on this, the lengths of the merged discharge passage 63 and the branch suction passage 83 can be shortened. . Further, by providing the left and right discharge valves 61 in the merged discharge passage 63, the substantial length of the merged discharge passage 63 ahead of the discharge valve 61 is shortened. Accordingly, the power loss can be reduced by shortening the passage through which the liquid flows as a whole.

  Further, in the merged discharge passage, the pressure regulating valve 70 is connected to the center, and the discharge port 73 is also connected to the center, so that the pressure adjusting valve 70 and the discharge port 73 are connected from the two left and right reciprocating pumps 42 and 42. The flow paths to reach (the flow paths that merge) are symmetrical, and pressure vibration can be reduced.

The operation of the pressure switch 10 attached to the reciprocating pump device 41 as described above will be described.
In the reciprocating pump device, for example, the main power supply of the motor 90 of the reciprocating pump device 41 is turned on while the valve 6 of the nozzle device 2 is opened. The main power switch is provided separately from the pressure switch 10, but the motor 90 is always off when the main power switch is off, and the pressure switch 10 when the main power switch is on. If the microswitch 17 is turned on, the motor 90 is turned on. If the microswitch 17 is turned off, the motor 90 is turned off.

When the main power switch is turned on, the fluid pressures in the A chamber 29 and the B chamber 30 inside the pressure switch 10 connected to the discharge port 73 of the reciprocating pump device 41 are low. At this time, since the pressure in the reciprocating pump device 41 is almost atmospheric pressure, the air vent valve 76 is open.
When the reciprocating pump device 41 is activated, when the air in the reciprocating pump device 41 is extracted from the open air vent valve 76 and the pump starts to operate normally, liquid is discharged from the reciprocating pump device 41 to the air vent valve 76, While 76 becomes a closed state, the hydraulic pressure in the reciprocating pump device 41 increases, and the air vent valve 76 is held in the closed state.

When the valve 6 is kept open, the fluid pressure in the A chamber 29 and the B chamber 30 in the pressure switch 10 becomes P ₁ shown in FIG. FIG. 11 shows the hydraulic pressure in the B chamber). In this state, if the set pressure of the pressure regulating valve 70 is exceeded, the pressure regulating valve 70 is opened, and the discharge pressure (spray pressure) at this time is equal to or lower than the set pressure by the pressure regulating valve 70.

  Then, the liquid discharged from the discharge port 73 of the reciprocating pump device 41 flows into the A chamber 29 inside the main body of the casing 13 through the pump mounting pipe 11 of the pressure switch 10, and passes through the piston second passage 26 of the piston 16. To the piston first passage 24. The liquid reaching the piston first passage 24 presses the valve body 39b of the valve 39, opens the valve 39, and flows out into the B chamber 30 of the manifold 14. Then, the liquid reaching the B chamber 30 reaches the spray hose 1 through the hose connection pipe 12, and reaches the nozzle 5 through the nozzle pipe 4 from the valve 6 that is opened from the spray hose 1 to the nozzle device 2. Is sprayed.

At this time, the compression coil spring 36 urges the piston 16 toward the first position where the microswitch 17 is turned off as urging means. The spring load as the urging force at this time is Q here.
Further, the liquid flows from the A chamber 29 to the B chamber 30 through the valve 39 from the inside of the piston 16, so that a pressure loss occurs and a pressure difference is generated so that the pressure in the A chamber 20 becomes higher than that in the B chamber 30.
Thereby, the inner peripheral side fixed to the piston 16 of the diaphragm 15 is elastically deformed so as to protrude from the A chamber 29 toward the B chamber 30 side with respect to the outer peripheral side fixed to the manifold 14 and the casing 13. The piston 16 is pressed from the A chamber 29 side to the B chamber 30 side, that is, from the second position to the first position side. The pressure difference at this time and [Delta] P, when the diameter of the diaphragm 15 is D, based on the pressure loss, the force that presses the piston 16 to the first position side becomes ^{(πD 2/4) · ΔP} .

On the other hand, with respect to the piston 16 in which the piston pin 20 can freely move in and out from the space surrounded by the casing 13 and the manifold 14 (the space combining the A chamber 29 and the B chamber 30), the A chamber in which the piston 16 is stored. Since the hydraulic pressure in the 29 and B chambers 30 is higher than the outside, a force acts in the direction in which the piston pin 20 protrudes. Here, the diameter of the piston pin 20 is d, when the P ₁ of the B chamber 30 that approximates the fluid pressure of the pressure switch 10, the ^{(πd 2/4) · P} 1.

  However, the combined force of the urging force (spring load Q) of the compression coil spring 36 as the urging means and the force acting on the diaphragm 15 as the pressure receiving member due to the pressure difference based on the pressure loss is the above-described force. Therefore, the piston 16 is held in the first position, and the push button 17a of the micro switch 17 is not pushed.

That is, the ^{(πD 2/4) · ΔP} + Q> (πd 2/4) of the · P ₁ relationship. Incidentally, the load Q of the ^{spring, Q <(πd 2/4} ) · P 1 and is set to be, by the pressure difference based on the pressure loss is applied to the diaphragm 15 is a pressure receiving member, the piston pin 20 Therefore, the piston 16 is moved from the first position to the second position only by the urging force of the compression coil spring 36.
Here, the microswitch 17 is in a state in which the current to the motor 90 is cut off while the push button 17a is pressed, and the current is supplied to the motor 90 when the push button 17a is returned without being pressed. In the motor 90, a state where power is supplied is maintained.

When the valve 6 is closed from the open state in this state, the reciprocating pump device 41 is activated and the liquid discharge is stopped, and the pressure rises in the reciprocating pump device 41, the pressure switch 10, and the spray hose 1. .
At this time, the flow of the liquid stops, and the valve 39 on the rear end side of the piston 16 is closed. In the valve 39, the valve body 39b is formed on the valve seat 39a by the groove 39d of the valve seat 29a. Even in the contact state, the flow of liquid cannot be completely blocked, and the hydraulic pressure can be released.

Further, when the flow of the liquid stops at the position of the valve 39, no pressure loss occurs, and the valve 39 does not cause a pressure difference between the A chamber 29 and the B chamber 30.
Therefore, the force for moving the piston 16 from the second position to the first position is only the force of the compression coil spring 36, and the force from the diaphragm 15 that receives the pressure difference is lost.

Also, the A chamber 29 and B chamber 30, with the valve 6 is closed, by pump device 41 is operating, as shown in the graph of B chamber 30 in FIG. 11, the pressure from P ₁ P Will rise to _two . Thereby, the pressure which makes the piston pin 20 protrude as mentioned above becomes high. That is, the pressing force from the first position to the second position side increases.

As a result, the force pushing the piston 16 from the second position to the first position side is superior to the force pushing the piston 16 from the first position to the second position side. Move from the position to the second position.
That is, there is no force of a pressure difference based on the pressure loss, and a force pushing the piston pin 20 becomes stronger by an increase in the P ₁ of the hydraulic to ^{_{P 2, Q <(πd 2}} /4) · P 1 <( πd _^2/4) · P ² becomes reliably piston 16 will move from the first position to the second position.
At this time, the second position is a position where the micro switch 17 can be switched by pressing the push button 17 a of the micro switch 17. Therefore, in the micro switch 17, the push button 17a is pushed, and the power supply (current) to the motor 90 is cut off, that is, turned off. At this time, the hydraulic pressure does not increase peakly when the valve 6 at the tip of the spray hose 1 is closed, and the piston 16 suddenly moves and hits another member to generate an impact sound. Will not occur.

  Here, when the reciprocating pump device 41 is stopped, in the reciprocating pump device, the flow of the liquid is stopped in a state where the internal pressure is still high, and the pressure may be released from the protruding port 73 side because the valve 6 is closed. Therefore, in the reciprocating pump device 41, the water suction valve 81, the air vent valve 76, and the pressure regulating valve 70 are closed. Further, when the flow of the liquid stops, the discharge valve 61 is also closed.

  Here, when the liquid leaks at a place other than the discharge valve 61 on the reciprocating pump device 41 side, the pressure in the reciprocating pump device 41 decreases. At this time, the pressure on the pressure switch 10 side must decrease. In this case, the discharge valve 61 is maintained in a closed state, and the pressure on the pressure switch 10 side does not drop rapidly.

  When the valve 6 is changed from the closed state to the open state as described above, the pressure is released from the nozzle 5 side and the pressure on the pressure switch 10 side is reduced. At this time, the pressure in the B chamber 30 connected to the spray hose 1 is reduced in the pressure switch 10. At this time, even if the valve 39 is closed, the pressure escapes from the groove 39d of the valve seat 39a of the valve 39 to the B chamber 30 from the A chamber 29, and the pressures in the A chamber 29 and the B chamber 30 become the same. Moreover, the force which pushes out the piston pin 20 of the piston 16 falls by the pressure of the A chamber 29 and the B chamber 30 falling.

At this time, since the reciprocating pump device 41 is not operating while the power of the motor 90 is still cut off, the liquid is generated from the A chamber 29 toward the B chamber 30 so as to cause a pressure loss as described above. Is not flowing, no pressure loss that causes a pressure difference between the A chamber 29 and the B chamber 30 does not occur.
Therefore, in this case, the force that pushes the piston 16 from the second position to the first position is only the urging force of the compression coil spring 36.

Therefore, the piston 16 is in the second position until the force that pushes the piston pin 20 by the pressure in the A chamber 29 and the B chamber 30 becomes equal to or less than the biasing force of the compression coil spring 36, and the piston pin 20 is in the microswitch 17. The push button 17a is kept pressed and the motor 90 is not started.
As shown in FIG. 11, when the pressure in the pressure switch 10 decreases to P _{3, the} force for pushing the piston pin 20 becomes equal to or less than the urging force of the compression coil spring 36, and the piston 16 is moved to the second position by the compression coil spring 36. The piston pin 20 is moved from the position to the first position, the piston pin 20 is separated from the push button 17a of the micro switch 17, the micro switch 17 is turned on so that a current flows to the motor 90, and the reciprocating pump device 41 is operated.
That is, a ^{(πd 2/4) · P} 3 <Q <(πd 2/4) · P 1 <(πd 2/4) · P 2.

  According to such a pressure switch 10, after the valve 6 is opened and closed and the motor power is turned off, the pressure at which the motor power is turned on with the pressure switch is reduced even if the pressure drops due to leakage or the like. Since it can be set very low, hunting that repeatedly turns the motor on and off can be prevented.

  That is, as described above, while the valve 6 is open, the motor 90 is activated, and the liquid is being discharged from the reciprocating pump device 41, when the valve 6 is closed, the valve 6 is moved to the second position. In order to hold the piston for turning off the power in the first position for turning on the power, in addition to the biasing force of the compression coil spring 36, the pressure difference caused by the pressure loss based on the liquid discharged from the reciprocating pump device 41 and flowing. Therefore, the urging force (spring load) required for the compression coil spring 36 can be reduced accordingly.

As a result, the pressure (hydraulic pressure) in the pressure switch 10 when the piston 16 returns from the second position to the first position can be reduced, and the motor 90 can be reduced only by a slight decrease in pressure. Can be prevented from being turned off.
That is, as shown in FIG. 11, the pressure difference from the pressure P2 at which the microswitch 17 is off to the pressure P3 at which the microswitch 17 is on, that is, the hunting margin pressure is increased as compared with the conventional case. Can do. In other words, hunting can be prevented by using the pressure difference based on the pressure loss, rather than using a configuration in which the piston 16 is maintained at the first position only by the improper force of the spring.

  In the operation of the pressure switch 10, the seal and the sliding member are used in the portion of the piston pin 20 that protrudes and protrudes from the pressure switch 10 and the seal 27 that prevents water leakage in this portion. In this part, when spraying wettable powder, even if wettable powder particles enter, the diameter of the piston pin 20 can be made sufficiently small and the area of the sliding surface can be reduced. Can be prevented.

In addition, if the force to move the sliding member is sufficiently large with respect to the increase in sliding resistance caused by biting the wettable powder particles, no malfunction occurs. Here, since the piston pin has a small diameter, the sliding resistance is small and no malfunction occurs.
On the reciprocating pump device 41 side, the piston is not driven by a weak force such as the difference between the force due to the internal pressure and the biasing force of the spring, but is driven by the motor 90, so that it is possible to spray with a wettable powder. .

In addition, since the diaphragm 15 is used without using a seal for the operation due to the pressure difference between the pressure receiving members of the piston 16, there is no influence of the wettable powder in this portion, and there is no problem in using the wettable powder. .
Further, by providing a groove in the valve seat 39a in the valve 39, the pressure difference between the A chamber and the B chamber can be eliminated when no pressure loss occurs, and when the valve body 39b comes into contact with the valve seat 39a. It is possible to make a structure in which foreign matter is not easily clogged.

  Further, when the piston 16 is moved by the elastic deformation of the diaphragm 15, the liquid needs to move between the A chamber 29 and the B chamber 30, but even if the valve 39 is closed, the liquid passes through the groove of the valve 39. Can be moved. Even when the valve 39 is closed because the liquid flow is stopped, as in the case where the valve 6 is opened from the closed state, the diaphragm 15 returns the piston 16 from the second position to the first position. In addition, the liquid can move through the groove 39d of the valve seat 39a. Furthermore, since the liquid must pass through the space in the narrow groove 39d, the sudden movement of the diaphragm 15 and the piston 16 can be buffered and prevented.

Further, the pressure switch has a simple configuration in which the piston 16 moves in the axial direction, and maintenance is easy.
Further, the micro switch 17 is arranged in series with the motor 90, and the on / off of the motor 90 is controlled with a simple configuration in which the piston pin 20 turns on / off the micro switch 17 as the piston 16 moves. Therefore, an electronic control unit or the like is not required, and the manufacturing can be performed with a simple configuration and extremely inexpensively.
The amount of current flowing through the motor 90 may be controlled by using a variable resistor or the like that can change the resistance value instead of the micro switch 17 that is turned on and off, and an engine is used as a prime mover as in the conventional case. The engine speed may be controlled.

FIG. 12 shows a first modification of the above embodiment. As a pressure loss means, an orifice (pressure loss means) 40 is provided in the enlarged diameter portion 25 of the piston 16 instead of the valve 39. Is. In contrast to the above example, in the first modification, the valve seat 39a, the valve body 39b, the compression coil spring 39c, the groove 39d, and the like as the components of the valve 39 are eliminated, and the piston first passage 24 of the piston 16 is removed. An orifice 40 having a smaller inner diameter is provided at the rear end, and the other configurations are the same as those in the above example.
And in the 1st modification, the orifice 40 is comprised with the member which has a hole in which a diameter becomes small as it goes to the rear side, and the said member is the rear-end part of the piston 1st channel | path 24 of piston 16. It is in a state of being inserted (inserted) and fixed.

The orifice 40 reduces the inner diameter at the portion of the piston first passage 24 where the liquid is discharged, resulting in a pressure loss. As with the valve 39, the liquid passes through the piston first passage 24 in the A chamber 29. The pressure loss occurs in the state where the gas flows from the chamber B to the chamber B 30, and the fluid pressure in the chamber A 29 becomes higher than the fluid pressure in the chamber B 30.
By using the orifice 40, the structure can be made simpler than the structure using the valve 39, and the manufacturing can be facilitated and the cost can be reduced. However, if the diameter of the orifice 40 is narrow, there is a possibility that foreign matters are easily clogged. There is.

  FIG. 13 shows a second modification of the above-described embodiment. As a pressure receiving member, instead of the diaphragm 15, the piston 16 can be moved in the axial direction within a cylinder (tubular member) 40a. In addition, a seal 21a is provided between the piston 16 and the cylinder 40a. In the second modified example, the diaphragm 15 is eliminated, the cylinder 40a and the seal 21a are provided, and the shape of the piston 16, the shape of the casing 13 holding the cylinder 40a, and the shape of the manifold 14 are changed to the cylinder. The configuration is changed corresponding to 40a, and the other configurations are the same as those in the above example.

  In the second modification, a cylindrical cylinder 40 a is sandwiched between the casing 13 and the manifold 14 to form a columnar internal space in the pressure switch 10. A piston 16 is disposed in the cylinder 40a. Since the rear portion of the piston 16 is not fixed to the diaphragm 15, there is no locking nut 28, and the main body portion 21 and the enlarged diameter portion 25 have a cylindrical shape having an outer peripheral surface along the inner peripheral surface of the cylinder 40a. The enlarged diameter portion 25 is provided with a groove along the circumferential direction, and an annular seal 21a is fitted in the groove. That is, the internal space of the cylinder 40a constitutes a predetermined space.

The piston 16 is movable in the cylinder 40a while sliding the seal 21a on the inner peripheral surface of the cylinder 40a. In this case, the piston 16 itself becomes a pressure receiving member that divides the inside of the pressure switch 10 into an A chamber 29 and a B chamber 30 and receives the pressure difference to press the piston 16. That is, the piston 16 divides the internal space of the cylinder 40a as a predetermined space into two spaces arranged along the axial direction of the cylinder 40a. And like the piston 16 of the above-mentioned embodiment, it can move between a 1st position and a 2nd position, and the said piston 16 serves as a pressure receiving member and a switch operation member.
By adopting such a configuration, the structure as the pressure receiving member can be made stronger than the structure using the diaphragm 15 and can have a more excellent pressure resistance. Not suitable for use of agents.
In addition, it is good also as a structure which provides a seal in the state fixed to the cylinder 40a side, and the piston 16 slides with respect to the said seal.

It is a figure which shows schematic structure of the spraying apparatus provided with the pressure switch which concerns on the 1st Embodiment of this invention. It is a perspective view which shows the said pressure switch attached to the said reciprocating pump apparatus. It is sectional drawing which shows the said pressure switch. It is a perspective view which shows the reciprocating pump apparatus as a pump with which the said pressure apparatus is attached. It is a side view which shows the said reciprocating pump apparatus. It is sectional drawing along the axial direction of the piston rod which shows the said reciprocating pump apparatus. It is XX arrow sectional drawing of FIG. It is sectional drawing along the direction orthogonal to the piston rod which shows the said reciprocating pump apparatus. It is a perspective view which shows the crankcase of the said reciprocating pump apparatus. It is a perspective view which shows the crankcase of the said reciprocating pump apparatus. It is a graph which shows the pressure change of the B chamber in the said pressure switch. It is principal part sectional drawing which shows the pressure switch of the 1st modification of the said embodiment. It is principal part sectional drawing which shows the pressure switch of the 2nd modification of the said embodiment. It is a graph which shows the change of the pressure in the piston type pressure detection means used with the unload valve used as the prior art example.

Explanation of symbols

10 Pressure switch 15 Diaphragm (pressure receiving member)
16 piston (switch operating member: also serves as a pressure receiving member of the second modification)
17 Microswitch (switch)
29 Room A (one space)
Room B (the other space)
36 Compression coil spring (biasing means)
39 Valve (pressure loss means)
39a Valve seat 39b Valve body 39c Compression coil spring (Valve urging means)
39d Groove 40 Orifice (pressure loss means)
40a Cylinder (tubular member)
41 Reciprocating pump device (pump)
90 motor (motor)

Claims (5)

A pressure switch for controlling a prime mover of the pump using a pressure change in the flow path generated according to opening and closing of the flow path of the liquid discharged from the pump,
A switch for switching the prime mover between a first control state which is a normal operation state and a second control state which is an operation state which is lower than normal or a stop state;
When a part is disposed in the predetermined space of the flow path and is movable between the first position and the second position, and the pressure in the predetermined space becomes relatively high due to the pressure change. When the switch is moved from the first position to the second position and the switch is in the first position, the switch is switched to the first control state and is held in the second position. A switch operating member for switching to and holding the control state;
By urging the switch operation member from the second position toward the first position, the switch operation at the second position when the inside of the predetermined space becomes a lower pressure than the high pressure. Biasing means for moving the member back to the first position;
Pressure loss means for generating a positional pressure difference in the predetermined space by generating a pressure loss when liquid is discharged by the pump;
A pressure switch, comprising: a pressure receiving member that receives a positional pressure difference in the predetermined space and presses the switch operating member from the second position side toward the first position side. The pressure receiving member divides the predetermined space into two spaces,
The pressure loss means allows the liquid discharged from the pump to flow over the two divided spaces, and is discharged from the operating pump to be discharged from one of the two spaces to the other space. 2. The pressure switch according to claim 1, wherein a pressure loss is generated by the liquid flowing in the first pressure to generate a pressure difference between the two spaces.   3. The pressure switch according to claim 2, wherein the pressure receiving member is a diaphragm that is connected to the switch operating member and divides the predetermined space into two. A cylindrical member having an internal space serving as the predetermined space;
The pressure receiving member functions as the switch operating member, and the internal space of the cylindrical member serving as the predetermined space is divided into two spaces that are aligned along the axial direction of the cylindrical member and the cylindrical shape The pressure switch according to claim 2, wherein a piston is movable in the member between the first position and the second position along the axial direction of the cylindrical member. The pressure loss means includes a flow path that allows the liquid discharged from the pump to flow over the two spaces partitioned by the pressure receiving member, a valve seat provided in the flow path, A valve body disposed on the downstream side of the valve seat of the liquid discharged from the pump, and valve body biasing means for biasing the valve body toward the valve seat,
5. The groove according to claim 2, wherein the valve seat is formed with a groove that allows liquid to flow in the flow path even when the valve body comes into contact with the valve seat. The described pressure switch.

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