JP5748106B2 - Fluid pump - Google Patents

Description

  The present invention relates to a fluid pump that supplies and discharges fluid by operating a piston, and more particularly to a technique for managing supply and discharge of fluid to and from a drive chamber in which a connection rod, a crank mechanism, and the like connected to the piston are arranged.

  As an example of a fluid pump, Patent Document 1 includes a piston that is reciprocally movable inside a cylinder, a drive unit that converts a driving force of a motor into a reciprocating operation by a crank mechanism and transmits the piston to the piston, and a cylinder head that has an intake air A vacuum pump with a valve body having a valve and an exhaust valve is shown.

  In Patent Document 1, a case is disposed at a position adjacent to a drive chamber (a crank chamber in the literature) that houses a crank mechanism, and exhaust gas from the valve body is supplied to an internal space of the case (an equipment chamber in the literature). An exhaust gas flow path is formed in the cylinder wall. The driving chamber and the internal space (equipment chamber) of the case communicate with each other through the driving chamber side exhaust port, and the case has a relaxation chamber side exhaust port that discharges exhaust gas in the internal space to the atmosphere. As a result, when the piston is operated, the exhaust gas is discharged to the outside by sequentially flowing through the exhaust gas flow path, the crank chamber, the drive chamber side exhaust port, the equipment chamber, and the relaxation chamber side exhaust port, and the pulsation pressure changes at the time of discharge To suppress exhaust noise.

  In addition, as an example of a fluid pump, Patent Document 2 includes a piston that is reciprocally movable inside a cylinder, a valve assembly in a cylinder head at the top of the cylinder, and a crankcase at the bottom of the cylinder. A compressor (air compressor) having a configuration in which a cross slider crank mechanism and a piston are connected by a piston rod is shown as a crank mechanism provided inside the crankcase.

  In Patent Document 2, an air passage is formed in a support member under the cylinder and a sealed chamber is connected to the air path (FIG. 5 in the literature), or an air filter is connected to the air path (Reference). Middle FIG. 6, FIG. 9, etc.) are shown. In these configurations, when the pressure in the space below the piston (on the opposite side of the cylinder head) decreases due to the operation of the piston, the air in the chamber is sucked in or is passed through an air filter (in the literature, an air cleaner). If the pressure in the space under the piston rises due to the operation of the piston, and the air under this piston rises, the air in this space is sent to the sealed chamber or through the air filter. The operation to send out is performed. With such a configuration, the operating power is reduced and temperature rise in the cylinder is suppressed.

JP 2011-7118 A Japanese Patent Laid-Open No. 10-266966

  In a fluid pump that supplies and discharges fluid to and from the piston head space by the operation of the piston, the pressure fluctuates even in the drive chamber (the space where the crank mechanism or the like is arranged) on the opposite side of the piston head when the piston reciprocates. Thus, when the driving chamber is a sealed space, the pressure variation in the driving chamber acts as a driving load for the actuator.

  In order to eliminate this inconvenience, it is considered effective to be able to supply and discharge fluid from the outside to the drive chamber as described in Patent Document 1 or Patent Document 2. In particular, in the configuration of the vacuum pump described in Patent Document 1, it is possible to guide the exhaust from the space on the cylinder head side to the drive chamber when the piston is operated in the exhaust direction. In the configuration of the compressor (air compressor) described (the configuration shown in FIGS. 6 and 9 in the literature), the flow of fluid to supply part of the fluid in the drive chamber to the cylinder when the piston operates in the intake direction. There is no waste. By adopting such a configuration, the load on the electric motor that drives the piston is reduced.

  However, when fluid is sucked into a drive chamber that has reached a negative pressure state in a fluid pump that supplies and discharges fluid by the operation of the piston, if the fluid contains dust or moisture, the drive system malfunctions. There is room for improvement.

  An object of the present invention is to rationally configure a fluid pump that can suppress suction of dust and moisture to the drive chamber while reducing the drive load by supplying and discharging fluid to and from the drive chamber that drives the piston.

The feature of the present invention is that the cylinder, the inside of the cylinder is divided into a pressure-increasing / depressurizing chamber on the cylinder head side and a driving chamber on the opposite side to the pressure-increasing / reducing chamber, and is provided so as to be reciprocally movable inside the cylinder A piston unit and a valve unit provided in the cylinder head so as to control a flow of fluid to the pressure increasing / decreasing chamber during reciprocating operation of the piston, the valve unit increasing / decreasing the fluid in the pressure increasing / decreasing chamber. a control space to be applied to the object, said has a supply and discharge space for supplying and discharging fluid to and from the pressurization chamber and the external space, Ri over a period of said drive chamber and the external space, and the drive chamber connected to the supply and discharge space used as the a gas passage from the discharge and the external space of the fluid to the outside space you allow inflow of fluid into the drive chamber, different exhaust space to the intake space of the valve unit from the Fluid path to Provided, the fluid path is merged in the merging space intermediate position of the vent path is that a fluid filter is provided in the merging space.

According to this configuration, when the piston operates in the exhaust direction and the drive chamber reaches a negative pressure state, the fluid from the ventilation path is sucked into the drive chamber while being filtered by the fluid filter. At the same time, the fluid from the fluid path connected to the merge space is also sucked into the drive chamber. In contrast, when the piston operates in the intake direction and the driving chamber reaches a pressurized state, the fluid in the driving chamber is sent out to the external space in a state of being filtered from the ventilation path by a fluid filter. At the same time, a part of the fluid in the driving chamber is sent to the fluid path connected to the merge space.
As a result, a fluid pump that can suppress suction of dust and moisture to the drive chamber while reducing the drive load by supplying and discharging fluid to and from the drive chamber that drives the piston has been configured. In particular, in this configuration, when the piston is operated, supply / exhaust sound is generated due to pressure fluctuations in the driving chamber. However, since the ventilation path and the fluid path are connected to the driving chamber, the air pressure in these spaces is reduced. The effect of noise reduction is achieved by suppressing rapid fluctuations.

  In the present invention, the valve unit is opened only when the piston is operated in the intake direction, and the negative pressure acting target as the pressure increasing / decreasing target sucks air as the fluid into the pressure increasing / decreasing chamber. An intake valve disposed in the control space, and an exhaust valve disposed in the supply / exhaust space to open only when the piston operates in the exhaust direction and to send air as the fluid to the pressurization chamber. By providing, it may be configured to create a negative pressure in the pressurization chamber, and an exhaust path for sending air from the exhaust valve to the merge space may be configured as the fluid path.

  According to this, when the piston is operated in the intake direction, air from the negative pressure target is sucked into the pressure-increasing / depressurizing chamber through the intake valve, and the air in the driving chamber is vented as the pressure in the driving chamber increases. Sent to the external space. On the contrary, when the piston is operated in the exhaust direction, the exhaust valve is opened to send the air in the pressurization / decompression chamber to the exhaust path as a fluid path. During this operation, the driving chamber has a negative pressure, so that air in the external space is sucked into the driving chamber in a state of being filtered by the fluid filter from the ventilation path, and air from the fluid path that merges with the ventilation path is driven into the driving chamber. Sucked into. In other words, the air sucked into the drive chamber from the external space is always filtered by the fluid filter, and dust and moisture are removed. At the time of this suction, a part of the air sent from the pressure-reducing chamber to the exhaust path is joined to the merge space. Therefore, the amount of air sucked from the external space can be reduced while reducing the load acting on the piston.

  According to the present invention, the valve unit is opened only when the piston is operated in the exhaust direction, and supplies the air as the fluid from the pressurization chamber to the pressurization target as the pressurization target. An exhaust valve disposed, and an intake valve disposed in the supply / exhaust space to open only when the piston operates in the intake direction and suck the air as the fluid into the pressurization / decompression chamber. An intake path for supplying pressurized air to the intake valve via the fluid filter may be configured as the fluid path, while being configured to create pressurized air in the pressurization / decompression chamber.

  According to this, when the piston is operated in the intake direction, air in the external space is filtered by the fluid filter, and is supplied from the merged space to the pressure increasing / decreasing chamber from the intake path as the fluid path. Air is sent out from the ventilation path to the merge space, and a part of the air sent to the merge space is sent to the intake path. On the contrary, when the piston operates in the exhaust direction, air from the pressurization / decompression chamber is supplied to the object to be pressurized via the exhaust valve, and the drive chamber becomes negative pressure during this operation. The air in the external space is sucked into the drive chamber in a state of being filtered by the fluid filter from the ventilation path, and part of the air in the intake path is also sucked into the drive chamber.

  In the present invention, a path block that forms the merging space is provided, and an opening for communicating the internal space of the path block and the external space is formed in a bottom wall of the path block, and an upper surface of the bottom wall is formed. You may form in the inclination attitude | position which becomes a level low as the position near the said opening | mouth.

  According to this, when water droplets are generated inside the route block, the water droplets flow along the slope of the upper surface of the bottom wall, reach the opening, and are easily discharged from the opening to the outside of the route block. Is done.

  The present invention forms a plurality of vertical walls in a posture rising from the upper surface of the bottom wall in an annular region surrounding the open port with the open port as a center, and the merging space is formed in a region surrounded by the vertical walls. The fluid path may be communicated with the ventilation path at a position outside the merge space.

  According to this, the fluid filter can be easily disposed in a state in which movement is restricted by the vertical wall, such as inserting the fluid filter into a space surrounded by a plurality of vertical walls.

  In the present invention, a cylindrical body may protrude downwardly at a position surrounding the opening on the lower surface side of the bottom wall of the path block.

  According to this, even when water droplets adhere to the bottom wall of the path block, the cylindrical body prevents the movement of the water droplets toward the opening, and even when the water droplets freeze, The fluid flow at the opening is not obstructed.

It is sectional drawing of the vacuum pump of 1st Embodiment. It is a perspective view from the upper surface of a route block. It is a perspective view from the lower surface of a path | route block. It is a vertical side view of a route block. It is sectional drawing which shows the positional relationship of a piston ring and a communicating hole at the time of the piston of 1st Embodiment moving to an exhaust direction and an intake direction. It is sectional drawing of the compressor of 2nd Embodiment.

DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, a first embodiment of the invention will be described with reference to the drawings.
[Basic configuration]
As shown in FIG. 1, a piston 2 is provided inside the cylinder 1 so as to be reciprocally movable, and a pressure increasing / decreasing chamber A is provided on the cylinder head side with respect to the piston 2, and the pressure increasing / decreasing chamber A with respect to the piston 2 A reciprocating vacuum pump as a fluid pump is configured by providing a driving chamber B that houses a crank mechanism C that transmits driving force to the piston 2 on the opposite side.

  This vacuum pump is used as a negative pressure source for a brake booster (not shown) of an automobile. By operating the piston 2 in the intake direction (right side in FIG. 1), a negative pressure is applied to the pressure increasing / decreasing chamber A. And the piston 2 is operated in the exhaust direction (left side in FIG. 1) to discharge air as a fluid from the pressurization / decompression chamber A to the outside. Note that this vacuum pump is not limited to that used in automobiles, but can be used in other devices that require negative pressure, and gas other than air may be used as a fluid.

[Specific configuration]
In this vacuum pump, the valve unit V is disposed at one end (cylinder head side) of the cylinder 1, whereby a pressure increasing / decreasing chamber A is formed between the valve unit V and the piston 2. A pump housing 3 is disposed on the other end side of the cylinder 1, and a driving chamber B is formed by the internal space of the pump housing 3.

  An electric motor 4 is provided in the pump housing 3, a base end of a connecting rod 6 is connected to a crank arm 5 that rotates integrally with an output shaft 4 </ b> A of the electric motor 4, and a piston 2 is connected to the tip of the connecting rod 6. doing. Thus, the crank mechanism C includes the crank arm 5 and the connecting rod 6. With this configuration, the crank mechanism C converts the rotational driving force of the output shaft 4A of the electric motor 4 into a reciprocating operating force, which is transmitted to the piston 2, and the piston 2 is reciprocated.

  The drive chamber B has a structure in which a space opened laterally in the pump housing 3 is closed by a plate-like closing member 7, and a ventilation hole 7 </ b> A is formed in the closing member 7. A path block 15 having an internal space communicating with the vent 7A is disposed on the outer lower surface of the closing member 7, and the path block 15 and the closing member 7 are connected and fixed to the pump housing 3 by fixing bolts 8. A cylindrical portion 16 that communicates with the internal space of the path block 15 projects in the direction of the valve unit V.

  The valve unit V includes an intake valve 22 at a portion communicating with an intake space 21A (an example of a control space) of the valve body 21, and exhausts at a portion communicating with an exhaust space 21B (an example of a supply / discharge space) of the valve body 21. A valve 23 is provided. The valve unit V includes a cover plate 24 that isolates the intake space 21A and the exhaust space 21B from the outside. The cover plate 24 applies a negative pressure to an external brake booster (an example of an object to be pressurized or depressurized). A tube 25 is connected. The intake valve 22 is made of a material that can be flexibly deformed, such as resin. When the air flow is blocked, the outer lip portion is in close contact with the valve body 21 and the air flow is allowed. The lip rises from the valve body 21 to form a space that allows the flow of air. Further, the exhaust valve 23 is configured to be biased in the closing direction by the spring 23S. When the air flow is blocked, the outer periphery is in close contact with the valve body 21 by the biasing force of the spring 23S, and the air When allowing the flow, the outer peripheral portion rises from the valve body 21 against the urging force of the spring 23 </ b> S to form a space that allows the flow of air. As the intake valve 22 and the exhaust valve 23, a ball or poppet urged in the closing direction by a spring, or a plate-like member that is operated by a hinge may be used.

  The valve body 21 is provided with a cylindrical projecting portion 26 that communicates with the exhaust space 21 </ b> B so as to project toward the pump housing 3. A cylindrical connecting tube 9 is provided to connect the protruding portion 26 and the cylindrical portion 16 in a communicating state. The connecting tube 9 has one end fitted on the protruding portion 26 and the other end connected to the cylindrical portion 16. It is provided in a form that fits outside.

  The valve unit V is connected to the pump housing 3 in such a manner that the tip of the connecting bolt 10 inserted through the through hole between the valve body 21 and the cover plate 24 is screwed into the female screw portion of the pump housing 3. This connection is performed by a plurality of connection bolts 10. When connecting, the cylinder 1 is sandwiched between the valve unit V and the pump housing 3, and the connection pipe 9 is sandwiched between the valve unit V and the path block 15. These are integrated.

  A ventilation path F is formed from the ventilation hole 7 </ b> A through the internal space of the path block 15 and across the opening 15 </ b> H drilled in the outer surface of the path block 15. A fluid path E that functions as an exhaust path is formed from the exhaust space 21 </ b> B of the valve body 21 through the connection pipe 9 to the internal space of the path block 15. The fluid path E merges at a merge space G formed at an intermediate position of the ventilation path F, and the merge space G includes an air filter 17 (an example of a fluid filter).

  As shown in FIG. 1, this vacuum pump is designed to be used in a posture in which the electric motor 4 is disposed at the upper portion and the path block 15 is disposed at the lower portion. As shown in FIGS. 2 to 4, the path block 15 is integrally formed with a flange body 15 </ b> C projecting laterally at the upper position of the block body having a circular bottom wall 15 </ b> A and a cylindrical wall 15 </ b> B continuous to the outer periphery. It has a configuration. A bolt hole 15D through which the fixing bolt 8 is inserted is formed in the flange body 15C, and a seal groove 15E for accommodating the seal 19 is formed at a position surrounding the block body.

  At the center position of the bottom wall 15A, an opening 15H for communicating the inner space and the outer space of the path block 15 is formed, and the upper surface of the bottom wall 15A is inclined such that the lower the position is the closer to the opening 15H. It is formed with a posture. A plurality of vertical walls 15F standing up from the bottom wall 15A are formed integrally with the bottom wall 15A in an annular region surrounding the opening 15H on the upper surface of the bottom wall 15A. Reinforcing ribs 15G connected to the plurality of vertical walls 15F and the bottom wall 15A are formed so as to extend radially around the opening 15H. Water can be allowed to flow along the slope of the upper surface of the bottom wall 15 </ b> A in the gaps between the plurality of vertical walls 15 </ b> F. The vertical dimension of the vertical wall 15F is set shorter than the distance from the top surface of the flange body 15C of the path block 15 to the bottom wall 15A.

  As shown in FIG. 3, a cylindrical body 15L that is cylindrical and protrudes downward is formed integrally with the bottom wall 15A at a position surrounding the opening 15H on the lower surface side of the bottom wall 15A. The rib body 15M connected to the lower surface of the wall 15A is formed in a posture extending radially around the opening 15H.

  The cylindrical portion 16 described above is formed on the side wall of the path block 15, and the cylindrical portion 16 communicates with the internal space of the block body formed by the bottom wall 15A and the cylindrical wall 15B. Further, in a state where the path block 15 is connected to the closing member 7, the vent 7 </ b> A drilled in the closing member 7 is configured to communicate with the internal space of the block body.

  In particular, a filter space in which the air filter 17 is provided is formed by a space surrounded by the vertical wall 15F in the internal space of the path block 15, and a hollow silencer 18 having a donut shape surrounding the filter space is formed. A merge space G is formed by combining the silencer space constituting the silencer 18 and the filter space. Note that the filter space is formed in a path on the outside space side of the merging space G (side closer to the opening 15H than the filter space) in the ventilation path F. The silencer space constituting the silencer 18 and the filter space are formed between the outer wall of the closing member 7 and the inner wall of the path block 15. In the filter space, an air filter 17 is provided in close contact with the outer wall of the closing member 7 and the inner wall of the path block 15. The air filter 17 is made of wool felt having a dust removal performance, paper material, urethane foam or the like.

  That is, the path block 15 has an internal space that constitutes the fluid path E, the ventilation path F, and the merge space G, and realizes dust removal and dehumidification by the air filter 17 and silence by the silencer 18. Further, since the bottom wall 15A of the path block 15 is formed in an inclined posture, water drops generated inside and water removed by the air filter 17 are directed to the upper surface of the bottom wall 15A along the direction of the opening 15H. And discharged to the outside through the opening 15H.

  Since the cylindrical body 15L protrudes from the lower surface side of the bottom wall 15A, for example, even in an environment where water droplets adhere to the lower surface of the bottom wall 15A and freezes, the water droplets freeze in the vicinity of the opening 15H. And the air permeability of the opening 15H can be maintained satisfactorily. The cylindrical body 15L is configured to suppress damage to the cylindrical body 15L by making the downward protruding amount smaller than the downward protruding amount of the head of the fixing bolt 8.

〔piston ring〕
As shown in FIG. 5, an annular groove 2G is formed on the entire outer periphery of the piston 2, and is narrower than the groove width of the annular groove 2G in the width direction (the operation direction of the piston 2) inside the annular groove 2G. A piston ring 30 is fitted so as to be freely displaceable. Further, a piston guide bush 31 is fitted on the outer periphery of the piston 2, the piston ring 30 and the piston guide bush 31 are in contact with the inner peripheral surface of the cylinder 1, and the outer periphery at both ends of the piston 2 is the inner peripheral surface of the cylinder 1. It is comprised so that it may not touch. The annular groove 2G has a first side wall 2Ga on the pressurizing / decompressing chamber side, a second side wall 2Gb on the driving chamber side, and a bottom wall 2Gc serving as a bottom portion of the annular groove 2G positioned between them. The piston ring 30 has a triple structure in which three types of an inner ring 30A, an intermediate ring 30B, and an outer ring 30C are overlapped.

  The inner ring 30A is made of stainless steel and has a slit formed in the ring portion. The intermediate ring 30B and the outer ring 30C are made of tetrafluoroethylene resin, and a slit is formed in the ring portion. The slits of the inner ring 30A, the intermediate ring 30B and the outer ring 30C are the same as those generally formed to facilitate the enlargement of the inner diameter when fitted into the annular groove 2G. Also, the slit of the intermediate ring 30B is disposed at a position 180 degrees different from the slit of the inner ring 30A, and the slit of the outer ring 30C is disposed at a position 180 degrees different from the position of the slit of the intermediate ring 30B. The sealing performance is improved.

  The piston ring 30 exerts an urging force in a direction in which the inner ring 30A expands the radius. The urging force brings the outer periphery of the outer ring 30C into contact with the inner peripheral surface of the cylinder 1 and the inner ring 30A. A gap is formed between the peripheral surface and the bottom wall 2Gc of the annular groove 2G.

  A plurality of communication holes 2T for communicating the bottom wall 2Gc of the annular groove 2G and the inside of the piston 2 are formed, and the communication holes 2T communicate with the drive chamber B. When the piston 2 operates in the intake direction, as shown in FIG. 5B, the piston ring 30 is displaced in the direction of the first side wall 2Ga and comes into contact with the first side wall 2Ga. To prevent air flow from communicating to the communication hole 2T. On the contrary, when the piston 2 operates in the exhaust direction, as shown in FIG. 5A, the piston ring 30 is displaced in the direction of the second side wall 2Gb and comes into contact with the second side wall 2Gb. In order to form a gap between the piston ring 30 and the first side wall 2Ga, the flow of air from the pressurization / decompression chamber A to the communication hole 2T is allowed.

[Operation form of the first embodiment]
Due to such a configuration, when the piston 2 operates in the intake direction, the piston ring 30 is displaced to a position where it abuts (closely contacts) the first side wall 2Ga, so that the air from the pressure increasing / decreasing chamber A to the driving chamber B is Is blocked. By the operation of the piston 2, the intake valve 22 is opened and the air from the tube 25 is sucked into the pressurizing / decompressing chamber A to apply a negative pressure, so that the air in the driving chamber B flows from the vent 7A to the vent path F. It is sent to the outside of the pump through the opening 15H.

  Further, when the piston 2 operates in the exhaust direction, the exhaust valve 23 is opened, and the air from the pressure increasing / decreasing chamber A is sent to the fluid path E. At the same time, since the piston ring 30 is displaced to a position where it abuts against the second side wall 2Gb, the air in the pressure increasing / decreasing chamber A is sent to the communication hole 2T from the gap between the piston ring 30 and the first side wall 2Ga. In this operation, the driving chamber B reaches a negative pressure state. However, since air is sent from the communication hole 2T to the driving chamber B, the degree of negative pressure is low, and the amount of air sucked into the driving chamber B from the vent 7A is reduced. The In particular, since the ventilation path F that sends air to the vent 7A merges with the fluid path E (exhaust path) in the merging space G, the air from the fluid path E (exhaust path) is sent to the ventilation path F. Even when air is sucked into the drive chamber B due to negative pressure, the air in the fluid path E (exhaust path) and the air sucked in the open port 15H are mixed, and the amount of outside air sucked in Can be reduced. When air is sucked from the opening 15H, air filtered by the air filter 17 is sucked, so that dust and moisture (moisture) are removed by the air filter 17 and enter the driving chamber B. There is nothing.

  Further, when the piston 2 operates in the exhaust direction, the air in the pressure increasing / decreasing chamber A flows directly to the driving chamber B through the communication hole 2T. And the drive torque of the electric motor 4 is stabilized. In addition, driving the electric motor 4 with a constant load improves the durability of the electric motor 4 without changing the electric power supplied to the electric motor 4. During the reciprocating operation of the piston 2, air in the fluid path E and the ventilation path F flows intermittently and generates noise with pressure fluctuations, but the silencer 18 suppresses noise.

  In the first embodiment, the piston 2 may be simply provided with the piston ring 30 without forming the communication hole 2T in the piston 2.

Hereinafter, a second embodiment of the present invention will be described with reference to the drawings.
[Basic configuration]
As shown in FIG. 6, a piston 2 is provided inside the cylinder 1 so as to be reciprocally movable, a pressure increasing / decreasing chamber A is provided on the cylinder head side with respect to the piston 2, and a pressure increasing / decreasing chamber A with respect to the piston 2 A reciprocating compressor as a fluid pump is configured by providing a driving chamber B that houses a crank mechanism C that transmits driving force to the piston 2 on the opposite side.

  This compressor operates the piston 2 in the intake direction (right side in FIG. 6), sucks air as a fluid into the pressurizing / decompressing chamber A, and operates the piston 2 in the exhaust direction (left side in FIG. 6). Then, pressurized air as a fluid is discharged from the pressure-reducing chamber A to the outside. In this compressor, a gas other than air may be used as a fluid.

[Specific configuration]
This compressor is different from the first embodiment in the configuration of the valve unit V and differs in the configuration in that the piston 2 is not provided with the communication hole 2T, but other configurations are different from those in the first embodiment. It is common.

  That is, by arranging the valve unit V at one end (cylinder head side) of the cylinder 1, the pressure increasing / decreasing chamber A is formed between the valve unit V and the piston 2. A pump housing 3 is disposed on the other end side of the cylinder 1, and a drive chamber B is formed by the internal space of the pump housing 3.

  An electric motor 4 is provided in the pump housing 3, a base end of a connecting rod 6 is connected to a crank arm 5 that rotates integrally with an output shaft 4 </ b> A of the electric motor 4, and a piston 2 is connected to the tip of the connecting rod 6. doing. Thus, the crank mechanism C includes the crank arm 5 and the connecting rod 6.

  The drive chamber B has a structure in which a space opened laterally in the pump housing 3 is closed by a plate-like closing member 7, and a ventilation hole 7 </ b> A is formed in the closing member 7. A path block 15 having an internal space communicating with the vent 7 </ b> A is disposed outside the closing member 7, and the path block 15 and the closing member 7 are connected and fixed to the pump housing 3 by fixing bolts 8. Further, a cylindrical portion 16 that communicates with the internal space of the path block 15 protrudes from the path block 15 in the direction of the valve unit V.

  The valve unit V includes an intake valve 22 in a portion communicating with an intake space 21A (an example of supply / exhaust space) of the valve body 21 and exhausts a portion communicating with an exhaust space 21B (an example of a control space) of the valve body 21. A valve 23 is provided. In addition, the valve unit V includes a cover plate 24 that isolates the intake space 21A and the exhaust space 21B from the outside. The cover plate 24 includes a pressurization chamber A as an external pressurization target (an example of a pressurization target). A tube 25 for supplying pressurized air from is connected. The intake valve 22 is made of a material that can be flexibly deformed, such as rubber or resin. When the air flow is blocked, the outer lip portion is in close contact with the valve body 21 to allow the air flow. The lip portion lifts from the valve body 21 to form a space that allows the flow of air. Further, the exhaust valve 23 is configured to be biased in the closing direction by the spring 23S. When the air flow is blocked, the outer periphery is in close contact with the valve body 21 by the biasing force of the spring 23S, and the air When allowing the flow, the outer peripheral portion rises from the valve body 21 against the urging force of the spring 23 </ b> S to form a space that allows the flow of air.

  The valve body 21 is provided with a cylindrical projecting portion 26 communicating with the intake space 21 </ b> A so as to project toward the pump housing 3. A cylindrical connecting tube 9 is provided to connect the protruding portion 26 and the cylindrical portion 16 in a communicating state. The connecting tube 9 has one end fitted on the protruding portion 26 and the other end connected to the cylindrical portion 16. It is provided in a form that fits outside.

  The valve unit V is connected to the pump housing 3 in such a manner that the tip of the connecting bolt 10 inserted through the through hole between the valve body 21 and the cover plate 24 is screwed into the female screw portion of the pump housing 3. This connection is performed by a plurality of connection bolts 10. When connecting, the cylinder 1 is sandwiched between the valve unit V and the pump housing 3, and the connection pipe 9 is sandwiched between the valve unit V and the path block 15. These are integrated.

  A ventilation path F is formed from the vent hole 7 </ b> A through the internal space of the path block 15 and across the opening 15 </ b> H drilled in the outer surface of the path block 15. A fluid path E that functions as an intake path is formed from the intake space 21 </ b> A of the valve body 21 through the connecting pipe 9 to the internal space of the path block 15. The fluid path E merges at a merge space G formed at an intermediate position of the ventilation path F, and the merge space G includes an air filter 17 (an example of a fluid filter).

  In particular, a filter space in which the air filter 17 is provided is formed by a space surrounded by the vertical wall 15F in the internal space of the path block 15, and a doughnut-shaped hollow silencer 18 that surrounds the filter space is formed. A confluence space G is formed by combining the silencer space and the filter space that constitute 18. Note that the filter space is formed in a path on the outside space side of the merging space G (side closer to the opening 15H than the filter space) in the ventilation path F. The silencer space constituting the silencer 18 and the filter space are formed between the outer wall of the closing member 7 and the inner wall of the path block 15. In the filter space, an air filter 17 is provided in close contact with the outer wall of the closing member 7 and the inner wall of the path block 15. The air filter 17 is made of wool felt having a dust removal performance, paper material, urethane foam or the like.

  The path block 15 has an internal space that constitutes the fluid path E, the ventilation path F, and the merging space G as in the first embodiment, and also performs dust removal and dehumidification by the air filter 17, and the silencer 18 Realize mute. Further, since the bottom wall 15A of the path block 15 is formed in an inclined posture, water drops generated inside and water removed by the air filter 17 are directed to the upper surface of the bottom wall 15A along the direction of the opening 15H. And discharged to the outside through the opening 15H.

  A piston ring 30 is fitted into an annular groove formed on the entire outer periphery of the piston 2. Although not shown in detail in the drawing, the piston ring 30 has a structure in which a plurality of rings are overlapped from the inside to the outside, and tetrafluoroethylene resin is used for the outermost ring. Yes. A piston guide bush 31 is fitted on the outer periphery of the piston 2, the piston ring 30 and the piston guide bush 31 are in contact with the inner peripheral surface of the cylinder 1, and the outer periphery at both ends of the piston 2 is in contact with the inner peripheral surface of the cylinder 1. It is configured not to.

[Operation form of the second embodiment]
With such a configuration, when the piston 2 operates in the intake direction, the intake valve 22 is opened, so that air in the external space is sucked from the open port 15H and filtered by the air filter 17. The air is supplied from the path E (intake path) to the pressure increasing / decreasing chamber A. When this intake is performed, the pressure in the drive chamber B increases, so the air in the drive chamber B is sent out to the ventilation path F, and a part of this air merges in the merge space G (filter space and silencer space). In this state, it is sent to the fluid path E. That is, when the piston 2 operates in the intake direction, the external air and the air sent out from the driving chamber B merge in the merging space G and are supplied to the pressurizing / decompressing chamber A.

  Further, when the piston 2 operates in the exhaust direction (compression direction), the exhaust valve 23 is opened and air from the pressurizing / decompressing chamber A is sent out to the tube 25. At the same time, since the driving chamber B has a negative pressure, external air is sent from the opening 15H to the ventilation path F and sucked into the driving chamber B, and part of the air in the fluid path E enters the merge space G. Suction in the form of merging. That is, when the piston 2 operates in the exhaust direction, the fluid path E is not in communication with the pressurization / decompression chamber A, but when the drive chamber B reaches a negative pressure, air is sent out in the same manner as the chamber. The amount of air sucked from the external space can be reduced. In addition, since air that is sucked into the driving chamber B is always filtered through the air filter 17 in the filter space, dust and moisture (moisture) are removed by the air filter 17 and do not enter the driving chamber B. .

  Further, when the piston 2 is operated in the intake direction, the air in the drive chamber B is sent out, and when the piston 2 is operated in the exhaust direction, the air is sucked into the drive chamber B. Therefore, the width of the pressure fluctuation in the drive chamber B is reduced to stabilize the drive torque of the electric motor 4. In addition, driving the electric motor 4 with a constant load improves the durability of the electric motor 4 without changing the electric power supplied to the electric motor 4. During the reciprocating operation of the piston 2, air in the fluid path E and the ventilation path F flows intermittently and generates noise with pressure fluctuations, but the silencer 18 suppresses noise.

  The present invention can be used for all fluid pumps having a configuration in which a piston operates inside a cylinder.

DESCRIPTION OF SYMBOLS 1 Cylinder 2 Piston 15 Path | route block 15A Bottom wall 15F Vertical wall 15H Opening port 15L Cylindrical body 17 Fluid filter (air filter)
21A Control space / supply / discharge space (intake space)
21B Supply / discharge space / control space (exhaust space)
22 Intake valve 23 Exhaust valve A Pressure increase / decrease chamber B Drive chamber E Fluid path (exhaust path / intake path)
F Ventilation path G Merge space V Valve unit

Claims (5)

A cylinder,
A piston provided in a reciprocating manner inside the cylinder while partitioning the inside of the cylinder into a pressure increasing / decreasing chamber on the cylinder head side and a driving chamber opposite to the pressure increasing / decreasing chamber;
A valve unit provided in the cylinder head so as to control the flow of fluid to the pressure-increasing / decreasing chamber during the reciprocating operation of the piston,
The valve unit has a control space for allowing the fluid in the pressure-increasing / decreasing chamber to act on the object to be pressurized, and a supply / discharge space in which fluid is supplied / discharged between the pressure-increasing / decreasing chamber and the external space,
Ri over a period of said drive chamber and the external space, and a vent passage from the discharge and the external space of the fluid into the external space from the driving chamber you permit the flow of fluid to the drive chamber, the valve unit A fluid path connected to the supply / exhaust space used as an exhaust space different from the intake space, and the fluid path merges in a merge space at an intermediate position of the ventilation path, and a fluid filter is provided in the merge space pump. The valve unit is disposed in the control space to open only when the piston operates in the intake direction and sucks air as the fluid from the negative pressure target as the pressure target to the pressure chamber. An intake valve that is opened only when the piston is operated in the exhaust direction, and an exhaust valve that is disposed in the supply / exhaust space in order to send air as the fluid to the pressurization chamber. It is configured to create negative pressure in the pressurization / decompression chamber,
The fluid pump according to claim 1, wherein an exhaust path for sending air from the exhaust valve to the merge space is configured as the fluid path. A path block that forms the merging space is provided, and an opening is formed in the bottom wall of the path block to allow communication between the internal space of the path block and the external space, and the upper surface of the bottom wall is connected to the opening. fluid pump according to claim 1 or 2 is formed in an inclined position where the lower level closer position. A plurality of vertical walls in a posture rising from the upper surface of the bottom wall are formed in an annular region surrounding the open port with the open port as a center, and the merge space is formed in a region surrounded by the vertical walls, The fluid pump according to claim 3 , wherein the fluid path and the ventilation path communicate with each other at a position outside the merge space. The bottom wall of the lower side at the open mouth The fluid pump according to claim 3 or 4, wherein the tubular body is projected downward at a position surrounding the said path blocks.

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