The present invention relates to a fluid injection or suction device that injects or suctions fluid.
A fluid injection or suction device has been known as described in, for example, Patent Literature 1 in which two nozzles, each of which is provided for each of two spaces partitioned by a piston inserted in a cylinder, communicate with the exterior of the cylinder, and fluid is injected or suctioned between the exterior of the cylinder and the two spaces through the two nozzles. In this fluid injection or suction device, the piston is fixed, and at the time of fluid injection, the fluid is fed from a high-pressure source to one of the spaces, or at the time of fluid suction, the fluid is suctioned from one of the spaces to a low-pressure source. This fluid injection or suction device uses volume changes in the two spaces at this time to move the cylinder.
Patent Literature 1: Japanese Patent Application Laid-open No. 2016-203111
In the fluid injection or suction device described in Patent Literature 1, provided that the fluid injection quantity or suction quantity is constant, the cylinder can be moved at a constant velocity. However, it is assumed that there are circumstances where it is necessary to reduce the cylinder movement velocity for some reasons.
It is possible to reduce the cylinder movement velocity by adjusting a generated pressure from the high-pressure source or the low-pressure source. However, during fluid injection, when the cylinder movement velocity is reduced by decreasing the generated pressure from the high-pressure source, the fluid injection quantity decreases. In contrast, during fluid suction, when the cylinder movement velocity is reduced by increasing the generated pressure from the low-pressure source, the fluid suction quantity decreases.
It is also possible to reduce the cylinder movement velocity by designing the cylinder to increase the maximum volume of the two spaces in the cylinder or by designing the nozzle with a reduced diameter. However, as the maximum volume of the two spaces in the cylinder is increased, the diameter of the cylinder increases, which may limit the installation space, or as the nozzle diameter is reduced, this may lead to a decrease in the fluid injection quantity or suction quantity.
In view of the problems described above, the present invention has an object to provide a fluid injection or suction device capable of reducing a cylinder movement velocity with a simple configuration, while preventing an increase in body size and a decrease in fluid injection quantity or suction quantity.
A fluid injection or suction device according to the present invention injects fluid to a target space or suctions fluid from the target space through nozzles, the device comprising: a cylinder formed in a hollow tubular shape and closed at opposite opening end portions by closing members; a piston that is inserted in the cylinder in a relatively movable manner between the opposite opening end portions, and that partitions an interior of the cylinder into a first fluid chamber and a second fluid chamber; a guide extending from the piston inserted in the cylinder, penetrating the closing members to an exterior of the cylinder, and fixed to support the piston and guide movement of the cylinder in sliding contact with through holes in the closing members, the guide including a first internal flow passage that connects the first fluid chamber externally to a first external pipe so as to communicate with each other, and a second internal flow passage that connects the second fluid chamber externally to a second external pipe so as to communicate with each other, the guide having an area of a circumferential outer shape smaller than that of the piston; a first nozzle of the nozzles, through which the first fluid chamber and the target space communicate with each other; and a second nozzle of the nozzles, through which the second fluid chamber and the target space communicate with each other, wherein a pipe to communicate with a fluid pressure source that generates fluid at a predetermined pressure is configured to switch between the first pipe and the second pipe, and a flow passage from the fluid pressure source to the first nozzle and the second nozzle includes a short-circuit flow passage that short-circuits a flow passage communicating with the fluid pressure source and a flow passage not communicating with the fluid pressure source, and the short-circuit flow passage is provided with a throttle unit that throttles a flow passage.
The fluid injection or suction device according to the present invention can reduce the cylinder movement velocity with a simple configuration, while preventing an increase in body size and a decrease in fluid injection quantity or suction quantity.
Embodiments to implement the present invention are described below in detail with reference to the accompanying drawings.
With reference to
(Piston-Cylinder Mechanism)
The piston-cylinder mechanism 2 is a mechanism to inject fluid while moving the fluid injection position, or to suction fluid while moving the fluid suction position. The piston-cylinder mechanism 2 is located in a fluid injection or suction target space (hereinafter, referred to as “target space”) E. The piston-cylinder mechanism 2 is mainly made up of a movable cylinder 11, a piston 12, a first guide 13, and a second guide 14.
Specifically, the movable cylinder 11 is formed in a uniform hollow tubular shape in cross section, and the piston 12 with its circumferential outer shape formed along the inner circumferential surface of the movable cylinder 11 is inserted in the movable cylinder 11 in a relatively movable manner between opposite opening end portions of the movable cylinder 11. The first guide 13 and the second guide 14 are formed to extend in a uniform solid rod-like shape in cross section, and to have an area of their circumferential outer shape smaller than the area of the circumferential outer shape of the piston 12, and are connected to the piston 12 or formed integrally with the piston 12 to be brought into a state as described below. That is, the first guide 13 extends outward from a portion of the inserted piston 12 directed toward one opening end portion of the movable cylinder 11 through the one opening end portion. The second guide 14 extends outward from a portion of the inserted piston 12 directed toward the other opening end portion of the movable cylinder 11 through the other opening end portion. At least one of the first guide 13 and the second guide 14 (the second guide 14 in the illustrated example) is fixed to an external structure F external to the piston-cylinder mechanism 2 (or may be in the target space E. The same applies hereinafter). The piston 12 is supported through at least one of the guides 13 and 14. In this manner, the piston-cylinder mechanism 2 is configured such that the movable cylinder 11 is guided by the guides 13 and 14 to perform reciprocating motion, while being in sliding contact with the piston 12.
In the following descriptions, for the sake of easy explanation, it is assumed that the movable cylinder 11 is formed in a straight tubular shape, and the guides 13 and 14 straightly extend outward from the piston 12 inserted in the movable cylinder 11 along the shape of the movable cylinder 11 through opposite opening end rear portions of the movable cylinder 11. With this configuration, the movable cylinder 11 moves straightly in a direction D1 from the piston 12 toward the first guide 13 or in a direction D2 from the piston 12 toward the second guide 14. As the directions D1 and D2, a direction can be selected from among various directions such as a vertical direction and a horizontal direction according to the installation orientation of the piston-cylinder mechanism 2.
One opening end portion of the movable cylinder 11 is closed by a first closing member 15, while the other opening end portion of the movable cylinder 11 is closed by a second closing member 16. The first guide 13 penetrates the first closing member 15 in a relatively movable manner. The second guide 14 penetrates the second closing member 16 in a relatively movable manner. The guides 13 and 14 guide the movement of the movable cylinder 11 by coming into sliding contact, on their outer circumferential surfaces, with the inner circumferential surfaces of through holes in the closing members 15 and 16, respectively.
An annular sealing member 17 such as an O-ring is held in a groove that is formed into a recess extending over the entire inner circumferential surface of the through hole in the first closing member 15 opposed to the outer circumferential surface of the first guide 13. An annular sealing member 18 similar to the sealing member 17 is held in a groove that is formed into a recess extending over the entire inner circumferential surface of the through hole in the second closing member 16 opposed to the outer circumferential surface of the second guide 14. These sealing members 17 and 18 are configured to come into contact with the outer circumferential surfaces of the guides 13 and 14, respectively, to maintain the liquid tightness or airtightness between the inside and outside of the movable cylinder 11.
The internal space of the movable cylinder 11 closed by the two closing members 15 and 16 is partitioned by the inserted piston 12 into two spaces, a first fluid chamber 19 and a second fluid chamber 20. Specifically, the first fluid chamber 19 is defined by the piston 12, the first closing member 15, the movable cylinder 11, and the first guide 13, while the second fluid chamber 20 is defined by the piston 12, the second closing member 16, the movable cylinder 11, and the second guide 14. For example, provided that the cross-sectional outer shapes of the guides 13 and 14 do not overlap the cross-sectional outer shape of the piston 12 when viewed from the direction D1 or the direction D2, the first fluid chamber 19 and the second fluid chamber 20 are cylindrical spaces.
In order to exactly partition the internal space of the movable cylinder 11 into two spaces, the first fluid chamber 19 and the second fluid chamber 20, an annular sealing member 21 such as an O-ring is held in a groove that is formed into a recess extending over the entire outer circumferential surface of the piston 12 opposed to the inner circumferential surface of the movable cylinder 11. This sealing member 21 is configured to come into sliding contact with the inner circumferential surface of the movable cylinder 11 when the movable cylinder 11 moves along the guides 13 and 14, and maintain the liquid tightness or airtightness between the first fluid chamber 19 and the second fluid chamber 20.
In a mobile element, such as the movable cylinder 11 and the closing members 15 and 16, that moves relative to a stationary element such as the piston 12 and the guides 13 and 14, a first communication passage 22 is formed through which the first fluid chamber 19 communicates with the target space E. In the illustrated example, the first communication passage 22 is drilled in the first closing member 15. In the mobile element, a second communication passage 23 is also formed through which the second fluid chamber 20 communicates with the target space E. In the illustrated example, the second communication passage 23 is drilled in the second closing member 16.
The first communication passage 22 described above is provided with a first nozzle 24 having a hollow tubular shape and protruding toward the target space E. Similarly to the above, the second communication passage 23 described above is provided with a second nozzle 25 having a hollow tubular shape and protruding toward the target space E. The first nozzle 24 and the second nozzle 25 inject fluid in the fluid chambers 19 and 20 to the target space E, or suction fluid in the target space E into the fluid chambers 19 and 20 according to the type of fluid pressure source (described later) of the external piping system 3 connected to the piston-cylinder mechanism 2. The first nozzle 24 has a significantly smaller flow-passage cross-sectional area than the effective area of the inner surface of the first fluid chamber 19, to which a fluid pressure in the first fluid chamber 19 is applied in the direction D1 (hereinafter, referred to as “first effective pressure-receiving area”). The second nozzle 25 has a significantly smaller flow-passage cross-sectional area than the effective area of the inner surface of the second fluid chamber 20, to which a fluid pressure in the second fluid chamber 20 is applied in the direction D2 (hereinafter, referred to as “second effective pressure-receiving area”). In the following descriptions, for the sake of easy explanation, the first effective pressure-receiving area and the second effective pressure-receiving area are defined as an equal effective cylinder pressure-receiving area S, and the flow-passage cross-sectional area of the first nozzle 24 and the flow-passage cross-sectional area of the second nozzle 25 are defined as being equal to each other.
Inside the first guide 13, a first internal flow passage 26 is formed connecting the first fluid chamber 19 and the external piping system 3 so as to communicate with each other. Specifically, the first internal flow passage 26 extends from a first inner opening 27 that is open toward the first fluid chamber 19 at a portion of the first guide 13 near the piston 12 to a first outer opening 28 that is open toward the exterior of the piston-cylinder mechanism 2 at an extended end portion of the first guide 13. The first outer opening 28 is provided with a first connector 29 that connects the first internal flow passage 26 to the external piping system 3 so as to communicate with each other.
Inside the first guide 13, the piston 12, and the second guide 14, a second internal flow passage 30 is formed connecting the second fluid chamber 20 and the external piping system 3 so as to communicate with each other. Specifically, the second internal flow passage 30 extends from a second inner opening 31 that is open toward the second fluid chamber 20 at a portion of the second guide 14 near the piston 12 to a second outer opening 32 that is open toward the exterior of the piston-cylinder mechanism 2 at another extended end portion of the first guide 13 separately from the first outer opening 28. The second outer opening 32 is provided with a second connector 33 that connects the second internal flow passage 30 to the external piping system 3 so as to communicate with each other.
The piston-cylinder mechanism 2 configured as described above has substantially the same configuration as a fluid supply and suction unit disclosed in Japanese Patent Application Laid-open No. 2016-203111. However, the piston-cylinder mechanism 2 is different from this fluid supply and suction unit in that the piston-cylinder mechanism 2 includes an orifice flow passage 34 drilled in the piston 12. The orifice flow passage 34 includes a short-circuit flow passage that connects (short-circuits) the first fluid chamber 19 and the second fluid chamber 20 so as to communicate with each other, and an orifice (throttle) serving as a throttle unit that throttles this short-circuit flow passage. The flow-passage cross-sectional area of the orifice flow passage 34 is set to a significantly smaller value than the effective cylinder pressure-receiving area S described above.
The piston 12 also functions as a stopper that regulates the movement of the movable cylinder 11 by abutting the second closing member 16 when the movable cylinder 11 moves in the direction D1, or by abutting the first closing member 15 when the movable cylinder 11 moves in the direction D2. The position of the first closing member 15 when the movement of the movable cylinder 11 in the direction D1 is regulated is referred to as “D1 regulated position”. The state of the fluid device 1 when the movement of the movable cylinder 11 is regulated at this position is referred to as “D1 regulated state”. The position of the second closing member 16 when the movement of the movable cylinder 11 in the direction D2 is regulated is referred to as “D2 regulated position”. The state of the fluid device 1 when the movement of the movable cylinder 11 is regulated at this position is referred to as “D2 regulated state”.
In the D2 regulated state, it is assumed that the first closing member 15 closes the first inner opening 27, which makes it difficult for fluid to flow between the target space E and the first internal flow passage 26. In view of this assumption, the first closing member 15 includes a first protruding portion 35 that protrudes partially from the first closing member 15 toward the first fluid chamber 19. The first protruding portion 35 has a protruding amount that is set in such a manner that the first closing member 15 is spaced apart from the piston 12 to a position where the first closing member 15 is prevented from completely closing the first inner opening 27 when the first protruding portion 35 abuts the piston 12 in the D2 regulated state.
In the D1 regulated state, it is assumed that the second closing member 16 closes the second inner opening 31, which makes it difficult for fluid to flow between the target space E and the second internal flow passage 30. In view of this assumption, the second closing member 16 includes a second protruding portion 36 that protrudes partially from the second closing member 16 toward the second fluid chamber 20. The second protruding portion 36 has a protruding amount that is set in such a manner that the second closing member 16 is spaced apart from the piston 12 to a position where the second closing member 16 is prevented from completely closing the second inner opening 31 when the second protruding portion 36 abuts the piston 12 in the D1 regulated state.
(External Piping System)
The external piping system 3 includes a first external pipe 37, a second external pipe 38, a pressure connection pipe 39, a flow-passage switching valve 40, and a fluid pressure source 41. The first external pipe 37 is connected at one end to the first connector 29 described above, while being connected at the other end to the flow-passage switching valve 40. The second external pipe 38 is connected at one end to the second connector 33 described above, while being connected at the other end to the flow-passage switching valve 40. The pressure connection pipe 39 is connected at one end to the flow-passage switching valve 40, while being connected at the other end to the fluid pressure source 41. As the flow-passage switching valve 40, a three-way solenoid valve is used. The three-way solenoid valve includes a first port connecting to the first external pipe 37, a second port connecting to the second external pipe 38, and a pressure source port connecting to the pressure connection pipe 39. The three-way solenoid valve is configured to be capable of closing at least either the first port or the second port by external control. Switching between the ports of the three-way solenoid valve makes it possible for fluid to flow between the fluid pressure source 41 and the target space E through the piston-cylinder mechanism 2 via either a first flow-passage system or a second flow-passage system. The first flow-passage system is made up of the first external pipe 37, the first internal flow passage 26, the first fluid chamber 19, the first communication passage 22, and the first nozzle 24. The second flow-passage system is made up of the second external pipe 38, the second internal flow passage 30, the second fluid chamber 20, the second communication passage 23, and the second nozzle 25.
As the flow-passage switching valve 40, two units of two-way solenoid valves may be used instead of using the three-way solenoid valve. Specifically, the pressure connection pipe 39 connected to the fluid pressure source 41 may be branched into two pipes so as to connect a branch port of one of the two branched pipes to the first external pipe 37 through one of the two-way solenoid valves, and so as to connect a branch port of the other of the two branched pipes to the second external pipe 38 through the other two-way solenoid valve. The two-way solenoid valve connected to the first external pipe 37 is opened, while the two-way solenoid valve connected to the second external pipe 38 is closed, so that it is possible for fluid to flow between the fluid pressure source 41 and the target space E through the piston-cylinder mechanism 2 via the first flow-passage system. In contrast, the two-way solenoid valve connected to the first external pipe 37 is closed, while the two-way solenoid valve connected to the second external pipe 38 is opened, so that it is possible for fluid to flow between the fluid pressure source 41 and the target space E through the piston-cylinder mechanism 2 via the second flow-passage system. In short, the flow-passage switching valve 40 can be of any type, provided that the flow-passage switching valve 40 is an externally-controllable solenoid valve that enables fluid to flow between the fluid pressure source 41 and the target space E through the piston-cylinder mechanism 2 via either the first flow-passage system or the second flow-passage system.
As the fluid pressure source 41, a high-pressure source is used when fluid is injected from the fluid chambers 19 and 20 to the target space E through the nozzles 24 and 25, while a low-pressure source is used when fluid is suctioned from the target space E into the fluid chambers 19 and 20 through the nozzles 24 and 25.
The high-pressure source generates fluid at a higher pressure than the pressure in the target space E (hereinafter, referred to as “target space pressure”) Ptgt. Specifically, the generated pressure from the high-pressure source is set to a pressure higher than a pressure (Ptgt+Δp) calculated in consideration of a flow passage loss and other factors Op from the high-pressure source to the nozzles 24 and 25 (such as the first flow-passage system or the second flow-passage system) relative to the target space pressure Ptgt. For example, the high-pressure source includes a fluid storage tank that stores fluid therein, and a pump that pressurizes the fluid in this fluid storage tank to a given pressure, and may further include a regulator, a buffer tank, and other devices to regulate the pressure at a given level. However, when the pressure (Ptgt+Δp), which is calculated in consideration of a flow passage loss and other factors Op from the high-pressure source to the fluid chamber relative to the target space pressure Ptgt, is lower than the atmospheric pressure, the high-pressure source may be omitted and the pressure source port may be opened to the atmosphere.
The low-pressure source generates fluid at a lower pressure than the target space pressure Ptgt. Specifically, the generated pressure from the low-pressure source is set to a pressure lower than a pressure (Ptgt−Δp) calculated in consideration of a flow passage loss and other factors Op from the nozzles 24 and 25 to the low-pressure source (such as the first flow-passage system or the second flow-passage system) relative to the target space pressure Ptgt. For example, the low-pressure source includes a vacuum pump, and may further include a regulator, a buffer tank, and other devices to regulate the pressure at a given level. However, when the target space pressure Ptgt is higher than a pressure calculated by adding the flow passage loss and other factors Op from the nozzles 24 and 25 to the low-pressure source to the atmospheric pressure, the low-pressure source may be omitted and the pressure source port may be opened to the atmosphere.
(Control System)
The control system 4 includes a first proximity detector 42, a second proximity detector 43, and a controller 44. The first proximity detector 42 is located and configured to output a detection signal when detecting the movement of the movable cylinder 11 to the D1 regulated position. The second proximity detector 43 is located and configured to output a detection signal when detecting the movement of the movable cylinder 11 to the D2 regulated position. For the proximity detectors 42 and 43, various detection methods can be employed, including a contact method with a limit switch or the like, and a non-contact method with a proximity sensor using light, magnetism, or electrostatic induction. The controller 44 switches between the ports of the flow-passage switching valve 40 by outputting a control signal based on two output signals from the first proximity detector 42 and the second proximity detector 43.
The controller 44 includes a microcomputer including a processor such as a CPU (Central Processing Unit). This microcomputer includes a ROM (Read Only Memory), a RAM (Random Access Memory), an input/output interface, and other devices that are connected to the processor by an internal bus such that these devices can communicate with the processor. The controller 44 controls the operation of the fluid device 1 by performing software processing in which the processor of the microcomputer reads an operation control program for the fluid device 1 from the ROM into the RAM, and executes the operation control program. However, the operation control of the fluid device 1 in the controller 44 may be conducted partially or entirely by means of the hardware configuration of the fluid device 1.
As described above, various kinds of fluid can be used as the fluid to be injected or suctioned in the fluid device 1 including the piston-cylinder mechanism 2, the external piping system 3, and the control system 4, appropriate to the intended use of the fluid device 1. For example, for cleaning purposes, a water soluble detergent, an organic solvent, or an oil can be used other than water, and further in gaseous form, air or various other kinds of gases can be used. For coating purposes, various kinds of paints can be used. For spraying purposes, various kinds of spray solutions can be used. When the fluid is in liquid form, it is preferable that the fluid has a viscosity of 0.2 cP to 1000 cP.
(Fluid Injecting Operation)
Next, with reference to
The balance between forces applied to the movable cylinder 11 moving in the direction D1 at a given velocity V1 in the injection mode is expressed as Equation (1) below by using the generated pressure PH from the high-pressure source, an internal pressure PB1 in the second fluid chamber 20, a friction force R (>0), and the effective cylinder pressure-receiving area S. The left side of Equation (1) below represents a force applied to the movable cylinder 11 in the direction D1, while the right side thereof represents a force applied to the movable cylinder 11 in the direction D2. In Equation (1) below, the generated pressure PH from the high-pressure source is used as an internal pressure PA1 in the first fluid chamber 19 without considering the pressure loss as describe above. A friction force R1 is generated between the movable cylinder 11 and the piston 12 (or the sealing member 21) or between the closing member 15 (or the sealing member 17) and the guide 13 and between the closing member 16 (or the sealing member 18) and the guide 14.
P
H
×S=P
B1
×S+R
1 (1)
A differential pressure ΔP1 (=PA1−PB1) between the internal pressure PA1 in the first fluid chamber 19 and the internal pressure PB1 in the second fluid chamber 20 is expressed as Equation (2) below by modifying Equation (1) described above, where the value of internal pressure PA1 in the first fluid chamber 19 is equal to the value of generated pressure PH from the high-pressure source. It is understood from this equation that the internal pressure PA1 in the first fluid chamber 19 becomes higher than the internal pressure PB1 in the second fluid chamber 20 (PA1>PB1)
ΔP1=PA1−PB1=R1/S (2)
The balance between the inflow rate and the outflow rate in the movable cylinder 11 is expressed as Equation (3) below by using the feed flow rate QH of the high-pressure source, an injection flow rate QA1 of the first nozzle 24, and an injection flow rate QB1 of the second nozzle 25. The left side of Equation (3) below represents an inflow rate to the movable cylinder 11, while the right side thereof represents an outflow rate from the movable cylinder 11.
Q
H
=Q
A1
+Q
B1 (3)
The volume of the second fluid chamber 20 decreases at a volume decrease rate [m3/s] represented as a value obtained by multiplying the velocity V1 of the movable cylinder 11 by the effective cylinder pressure-receiving area S. However, since the internal pressure PA1 in the first fluid chamber 19 is higher than the internal pressure PB1 in the second fluid chamber 20, a minute flow rate q1 (>0) of fluid flows from the first fluid chamber 19 into the second fluid chamber 20 through the orifice flow passage 34. This minute flow rate q1 is determined according to the flow-passage cross-sectional area of the orifice flow passage 34, the differential pressure ΔP1 (=PA1−PB1) between before and after the orifice flow passage 34, and other factors. Since the second nozzle 25 injects a flow rate of fluid obtained by adding the volume decrease rate of the second fluid chamber 20 and the minute flow rate q1, Equation (4) below holds for the injection flow rate QB1.
Q
B1
=S×V
1
+q
1 (4)
Equation (4) described above is modified into Equation (5) below to obtain the velocity V1 of the movable cylinder 11.
V
1=(QB1−q1)/S (5)
Next, for the sake of understanding the effects of the fluid device 1 in the injection mode due to the orifice flow passage 34, descriptions are made on a relational expression that holds for the velocity of the movable cylinder 11, the injection flow rate of the first nozzle 24, and the injection flow rate of the second nozzle 25 in a case where the orifice flow passage 34 is not included.
Similarly to Equation (1) described above, the balance between forces applied to the movable cylinder 11 moving in the direction D1 at a given velocity V1′ in the injection mode is expressed as Equation (6) below by using the generated pressure PH from the high-pressure source, an internal pressure PB1′ in the second fluid chamber 20, a friction force R1′, and the effective cylinder pressure-receiving area S. The left side of Equation (6) below represents a force applied to the movable cylinder 11 in the direction D1, while the right side thereof represents a force applied to the movable cylinder 11 in the direction D2.
P
H
×S=P
B1
′×S+R
1′ (6)
Similarly to Equation (3) described above, the balance between the inflow rate and the outflow rate in the movable cylinder 11 is expressed as Equation (7) below by using the feed flow rate QH of the high-pressure source, an injection flow rate QA1′ of the first nozzle 24, and an injection flow rate QB1′ of the second nozzle 25. The left side of Equation (7) below represents an inflow rate to the movable cylinder 11, while the right side thereof represents an outflow rate from the movable cylinder 11.
Q
H
=Q
A1
′+Q
B1′ (7)
Similarly to the above, the volume of the second fluid chamber 20 decreases at a volume decrease rate [m3/s] represented as a value obtained by multiplying the velocity V1′ of the movable cylinder 11 by the effective cylinder pressure-receiving area S. However, in a case where the piston-cylinder mechanism 2 does not include the orifice flow passage 34, a fluid flow is not generated between the first fluid chamber 19 and the second fluid chamber 20. For this reason, since the second nozzle 25 injects the fluid at a flow rate equal to the volume decrease rate of the second fluid chamber 20, Equation (8) below holds for the injection flow rate QB1′.
Q
B1
′=S×V
1′ (8)
A friction force generated between the movable cylinder 11 and the piston 12 or between the closing member 15 and the guide 13 and between the closing member 16 and the guide 14 varies exactly according to the velocity of the movable cylinder 11. However, as a force applied to the movable cylinder 11 in the direction D2 (see the right side of Equations (1) and (6) described above), the internal pressures PB1 and PB1′ in the second fluid chamber 20 are more significantly dominant than the friction forces R1 and R1′. In view of that, in Equations (1) and (6) described above, the friction force R1′ applied to the movable cylinder 11 moving at the velocity V1′ and the friction force R1 applied to the movable cylinder 11 moving at the velocity V1 are regarded as an equal value (R1′=R1), and then Equation (9) below holds based on Equations (1) and (6) described above.
P
B1
′=P
B1 (9)
Since the value of injection flow rate of the second nozzle 25 varies according to the differential pressure between the internal pressure in the second fluid chamber 20 and the target space pressure Ptgt, Equation (10) below holds where PB1′=PB1 as expressed by Equation (9) described above. It is understood from this equation that the injection flow rate QB′ of the second nozzle 25 when there is not the orifice flow passage 34 is equal to the injection flow rate QB of the second nozzle 25 when there is the orifice flow passage 34.
Q
B1
′=Q
B1 (10)
Equation (10) described above is substituted into Equation (8) described above and then Equation (8) is modified into Equation (11) below to obtain the velocity V′ of the movable cylinder 11.
V
1
′=Q
B1
/S (11)
Therefore, a velocity difference ΔV1 (=V1′−V1) between the velocity V1′ of the movable cylinder 11 when there is not the orifice flow passage 34 and the velocity V1 of the movable cylinder 11 when there is the orifice flow passage 34 is obtained by Equation (12) below based on Equations (5) and (11) described above. It is understood from this equation that the velocity V of the movable cylinder 11 when there is the orifice flow passage 34 is lower than the velocity V′ of the movable cylinder 11 when there is not the orifice flow passage 34.
ΔV1=V1′−V1=q1/S (12)
Equation (13) below holds based on Equations (3), (7), and (10) described above. It is understood from this equation that the injection flow rate QA1′ of the first nozzle 24 when there is not the orifice flow passage 34 is equal to the injection flow rate QA1 of the first nozzle 24 when there is the orifice flow passage 34.
Q
A1
′=Q
A1 (13)
The fluid device 1 includes the orifice flow passage 34 in the manner as described above, so that when the movable cylinder 11 moves in the direction D1 in the injection mode, the fluid device 1 can reduce the velocity of the movable cylinder 11, while preventing a decrease in the injection flow rate of the first nozzle 24 and the injection flow rate of the second nozzle 25.
When the controller 44 detects stop of the movable cylinder 11 at the D1 regulated position based on an output signal from the first proximity detector 42, the controller 44 outputs, to the three-way solenoid valve, a control signal for closing its first port in order to switch the movement direction of the movable cylinder 11 to the direction D2.
When the movable cylinder 11 moves in the direction D2 at a given velocity V, Equations (1) to (13) described above hold by a method as described below. That is, Equations (1) to (13) described above hold by interchanging the internal pressures PA1 and PA1′ in the first fluid chamber 19 and the internal pressures PB1 and PB1′ in the second fluid chamber 20, and by interchanging the injection flow quantities QA1 and QA1′ of the first nozzle 24 and the injection flow quantities QB1 and QB1′ of the second nozzle 25. Therefore, the fluid device 1 includes the orifice flow passage 34, and thus can reduce the velocity of the movable cylinder 11 in the direction D2, while preventing a decrease in the injection flow rate of the first nozzle 24 and the injection flow rate of the second nozzle 25.
When the controller 44 detects stop of the movable cylinder 11 at the D2 regulated position based on an output signal from the second proximity detector 43, the controller 44 outputs, to the three-way solenoid valve, a control signal for closing its second port in order to switch the movement direction of the movable cylinder 11 to the direction D1. With this operation, the movable cylinder 11 moves in the direction D1 again as illustrated in
(Fluid Suctioning Operation)
Next, with reference to
The balance between forces applied to the movable cylinder 11 moving in the direction D1 at a given velocity V2 in the suction mode is expressed as Equation (14) below by using the generated pressure PL from the low-pressure source, an internal pressure PA2 in the first fluid chamber 19, a friction force R2 (>0), and the effective cylinder pressure-receiving area S. The left side of Equation (14) below represents a force applied to the movable cylinder 11 in the direction D1, while the right side thereof represents a force applied to the movable cylinder 11 in the direction D2. In Equation (14) below, the generated pressure PL from the low-pressure source is used as an internal pressure PB2 in the second fluid chamber 20 without considering the pressure loss as described above.
P
A2
×S=P
L
×S+R
2 (14)
A differential pressure ΔP2 (=PA2−PB2) between the internal pressure PA2 in the first fluid chamber 19 and the internal pressure PB2 in the second fluid chamber 20 is expressed as Equation (15) below by modifying Equation (14) described above, where the value of internal pressure PB2 in the second fluid chamber 20 is equal to the value of generated pressure PL from the low-pressure source. It is understood from this equation that the internal pressure PA2 in the first fluid chamber 19 becomes higher than the internal pressure PB2 in the second fluid chamber 20 (PA2>PB2)
ΔP2=PA2−PB2=R2/S (15)
The balance between the inflow rate and the outflow rate in the movable cylinder 11 is expressed as Equation (16) below by using the suction flow rate QL of the low-pressure source, a suction flow rate QA2 of the first nozzle 24, and a suction flow rate QB2 of the second nozzle 25. The left side of Equation (16) below represents an outflow rate from the movable cylinder 11, while the right side thereof represents an inflow rate to the movable cylinder 11.
Q
L
=Q
A2
+Q
B2 (16)
The volume of the first fluid chamber 19 increases at a volume increase rate [m3/s] represented as a value obtained by multiplying the velocity V2 of the movable cylinder 11 by the effective cylinder pressure-receiving area S. However, since the internal pressure PA2 in the first fluid chamber 19 is higher than the internal pressure PB2 in the second fluid chamber 20, a minute flow rate q2 (>0) of fluid flows from the first fluid chamber 19 into the second fluid chamber 20 through the orifice flow passage 34. This minute flow rate q2 is determined according to the flow-passage cross-sectional area of the orifice flow passage 34, the differential pressure ΔP2 (=PA2−PB2) between before and after the orifice flow passage 34. Since the first nozzle 24 suctions a flow rate of fluid obtained by adding the volume increase rate of the first fluid chamber 19 and the minute flow rate q2, Equation (17) below holds for the suction flow rate QA2.
Q
A2
=S×V
2
+q
2 (17)
Equation (17) described above is modified into Equation (18) below to obtain the velocity V2 of the movable cylinder 11.
V
2=(QA2−q2)/S (18)
Next, for the sake of understanding the effects of the fluid device 1 in the suction mode due to the orifice flow passage 34, descriptions are made on a relational expression that holds for the velocity of the movable cylinder 11, the suction flow rate of the first nozzle 24, and the suction flow rate of the second nozzle 25 in a case where the orifice flow passage 34 is not provided.
Similarly to Equation (14) described above, the balance between forces applied to the movable cylinder 11 moving in the direction D1 at a given velocity V2′ in the suction mode is expressed as Equation (19) below by using the generated pressure PL from the low-pressure source, an internal pressure PA2′ in the first fluid chamber 19, a friction force R2′, and the effective cylinder pressure-receiving area S.
P
A2
′×S=P
L
×S+R
2′ (19)
Similarly to Equation (16) described above, the balance between the inflow rate and the outflow rate in the movable cylinder 11 is expressed as Equation (20) below by using the suction flow rate QL of the low-pressure source, a suction flow rate QA2′ of the first nozzle 24, and a suction flow rate QB2′ of the second nozzle 25.
Q
L
=Q
A2
′+Q
B2′ (20)
Similarly to the above, the volume of the first fluid chamber 19 increases at a volume increase rate [m3/s] represented as a value obtained by multiplying the velocity V2′ of the movable cylinder 11 by the effective cylinder pressure-receiving area S. In contrast, since the piston-cylinder mechanism 2 does not include the orifice flow passage 34, a fluid flow is not generated between the first fluid chamber 19 and the second fluid chamber 20. For this reason, since the first nozzle 24 suctions the fluid at a flow rate equal to the volume increase rate of the first fluid chamber 19, Equation (21) below holds for the suction flow rate QA2′.
Q
A2
′=S×V
2′ (21)
As explained above, in Equations (14) and (19) described above, the friction force R2′ applied to the movable cylinder 11 moving at the velocity V2′ and the friction force R2 applied to the movable cylinder 11 moving at the velocity V2 are regarded as an equal value (R2′=R2), and then Equation (22) below holds based on Equations (14) and (19) described above.
P
A2
′=P
A2 (22)
Since the suction flow rate of the first nozzle 24 becomes a value according to the differential pressure between the internal pressure in the first fluid chamber 19 and the target space pressure Ptgt, Equation (23) below holds where PA2′=PA2 as expressed by Equation (22) described above. It is understood from this equation that the suction flow rate QA2′ of the first nozzle 24 when there is not the orifice flow passage 34 is equal to the suction flow rate QA2 of the first nozzle 24 when there is the orifice flow passage 34.
Q
A2
′=Q
A2 (23)
Equation (23) described above is substituted into Equation (20) described above and then Equation (20) is modified into Equation (24) below to obtain the velocity V2′ of the movable cylinder 11.
V
2
′=Q
A2
/S (24)
Therefore, a velocity difference ΔV2 (=V2′−V2) between the velocity V2′ of the movable cylinder 11 when there is not the orifice flow passage 34 and the velocity V2 of the movable cylinder 11 when there is the orifice flow passage 34 is obtained by Equation (25) below based on Equations (18) and (24) described above. It is understood from this equation that the velocity V2 of the movable cylinder 11 when there is the orifice flow passage 34 is lower than the velocity V2′ of the movable cylinder 11 when there is not the orifice flow passage 34.
ΔV2=V2′−V2=q2/S (25)
Equation (26) below holds based on Equations (16), (20), and (23) described above. It is understood from this equation that the suction flow rate QB2′ of the second nozzle 25 when there is not the orifice flow passage 34 is equal to the suction flow rate QB2 of the second nozzle 25 when there is the orifice flow passage 34.
Q
B2
′=Q
B2 (26)
The fluid device 1 includes the orifice flow passage 34 in the manner as described above, so that when the movable cylinder 11 moves in the direction D1 in the suction mode, the fluid device 1 can reduce the velocity of the movable cylinder 11, while preventing a decrease in the suction flow rate of the first nozzle 24 and the suction flow rate of the second nozzle 25.
When the controller 44 detects stop of the movable cylinder 11 at the D1 regulated position based on an output signal from the first proximity detector 42, the controller 44 outputs, to the three-way solenoid valve, a control signal for closing its second port in order to switch the movement direction of the movable cylinder 11 to the direction D2.
When the movable cylinder 11 moves in the direction D2 at the given velocity V2, Equations (14) to (26) described above hold by a method as described below. That is, Equations (14) to (26) described above hold by interchanging the internal pressures PA2 and PA2′ in the first fluid chamber 19 and the internal pressures PB2 and PB2′ in the second fluid chamber 20, and by interchanging the suction flow quantities QA2 and QA2′ of the first nozzle 24 and the suction flow quantities QB2 and QB2′ of the second nozzle 25. Therefore, the fluid device 1 includes the orifice flow passage 34, and thus can reduce the velocity of the movable cylinder 11 in the direction D2, while preventing a decrease in the suction flow rate of the first nozzle 24 and the suction flow rate of the second nozzle 25.
When the controller 44 detects stop of the movable cylinder 11 at the D2 regulated position based on an output signal from the second proximity detector 43, the controller 44 outputs, to the three-way solenoid valve, a control signal for closing its first port in order to switch the movement direction of the movable cylinder 11 to the direction D1. With this operation, the movable cylinder 11 moves in the direction D1 again as illustrated in
With reference to
As illustrated in
In the specific examples in
A fit groove 51 is formed into a recess on an end face 49 that is one of the opposite end faces 49 and 50 of the plug 46 in its axial direction, and that faces the first fluid chamber 19 (hereinafter, referred to as “first end face”). The fit groove 51 is an engagement portion into which a tip end portion of an axial tool is fitted to transmit an axial rotation force of the axial tool so as to rotate the plug 46 to be screwed in the through hole 45 or screwed out of the through hole 45. The fit groove 51 has a cross-sectional shape that matches the shape of the tip end portion of the axial tool to be used. For example, the fit groove 51 is a hexagonal hole in which a tip end portion of a hexagonal bar spanner serving as the axial tool is fitted, or a recessed groove in which a tip end portion of a flathead screwdriver serving as the axial tool is fitted. The orifice flow passage 34 can be provided without interfering with the fit groove 51. However, unless there is an adequate areal margin on the first end face 49, the orifice flow passage 34 may be provided in the manner as described below. That is, as illustrated in
A work through hole 52 is drilled in the first closing member 15 that is opposite to the first end face 49 of the plug 46 screw-fitted into the through hole 45 with respect to the first fluid chamber 19. The work through hole 52 is used at the time of replacement of the plug 46. The plug 46 is inserted through the work through hole 52 with the tip end portion of the axial tool fitted in the fit groove 51 of the plug 46, and thereby it is possible to screw-fit the plug 46 in the through hole 45. Except during replacement of the plug 46, the work through hole 52 is closed by screw-fitting a normally-closed lid 53 therein or by other means.
Based on Equations (12) and (25) described above, the velocity reduction amount of the movable cylinder 11 is set according to the values of minute flow quantities q1 and q2 of the orifice flow passage 34, while the values of minute flow quantities q1 and q2 vary according to the flow-passage cross-sectional area of the orifice flow passage 34. Therefore, provided that a plurality of plugs 46 are prepared in advance, and the orifice flow passages 34 of these plugs 46 are formed in various flow-passage cross-sectional areas, then a plug 46 having an appropriate flow-passage cross-sectional area is selected from among these plugs 46 and fitted into the through hole 45, so that the velocity of the movable cylinder 11 can be reduced by a desired reduction amount.
Next, with reference to
An opening 56 of the orifice flow passage 34 in the plug 46a, which is open toward the second fluid chamber 20, is formed so as to face a gap 57 formed between the conical face 54 and the opposed conical face 55 when the plug 46a is screw-fitted into the through hole 45a. With this configuration, the gap 57 formed between the conical face 54 and the opposed conical face 55 forms a portion of the orifice flow passage 34. A plurality of openings 56 that are open toward the second fluid chamber 20 may be formed. In this case, as illustrated in the drawings, the orifice flow passage 34 may branch off into multiple paths inside the plug 46a and the multiple paths may be connected to the respective openings 56, or the respective openings 56 may individually have the orifice flow passage 34.
The minute flow quantities q1 and q2 of fluid flows between the first fluid chamber 19 and the second fluid chamber 20 through the orifice flow passage 34 in the plug 46a including the gap 57. The spacing of the gap 57 varies according to the screwing amount of the male thread 47 of the plug 46a relative to the female thread 48 on the through hole 45a. With this configuration, the orifice flow passage 34 has a variable throttle valve that serves as a throttle unit and that uses the spacing of the gap 57 as a throttle opening of the flow passage. Therefore, the plug 46a enables the velocity of the movable cylinder 11 to be reduced by a desired reduction amount by adjusting the screwing amount described above. This can eliminate the necessity for replacement of the plug. Since the orifice flow passage 34 is provided with the variable throttle valve obtained by using the gap 57, the orifice flow passage 34 from which an orifice is omitted may simply serve as a short-circuit flow passage connecting (short-circuiting) the first fluid chamber 19 and the second fluid chamber 20 so as to communicate with each other.
Next, with reference to
The minute flow quantities q1 and q2 of fluid flows between the first fluid chamber 19 and the second fluid chamber 20 through the orifice flow passage 34 in the plug 46b including the gap 57a. The spacing of the gap 57a varies according to the screwing amount of the male thread 47 of the plug 46b relative to the female thread 48 on the through hole 45. With this configuration, the orifice flow passage 34 has a variable throttle valve that serves as a throttle unit and that uses the spacing of the gap 57a as a throttle opening of the flow passage. Therefore, the plug 46b enables the velocity of the movable cylinder 11 to be reduced by a desired reduction amount by adjusting the screwing amount described above. This can eliminate the necessity for replacement of the plug. Since the orifice flow passage 34 is provided with the variable throttle valve obtained by using the gap 57a, the orifice flow passage 34 from which an orifice is omitted may simply serve as a short-circuit flow passage connecting (short-circuiting) the first fluid chamber 19 and the second fluid chamber 20 so as to communicate with each other.
Next, with reference to
In contrast to this, the through hole 45b is different from the through hole 45 in that the plug 46 is configured to be able to be screwed in from the first fluid chamber 19 only halfway through the through hole 45b toward the second fluid chamber 20. In a portion of the through hole 45b closer to the second fluid chamber 20 than the second end face 50 of the plug 46 screw-fitted into the through hole 45b, the valve body 59 is held in such a manner as to be movable in parallel to the penetration direction of the through hole 45b. The valve body 59 includes one or a plurality of fluid passage holes 60 through which fluid having flowed out of the orifice flow passage 34 in the plug 46 screw-fitted into the through hole 45b passes to the second fluid chamber 20. The valve body 59 is formed so as to close an opening of the orifice flow passage 34 that is open toward the second end face 50, or close an intermediate flow passage (not illustrated) connected to this opening, when the valve body 59 moves in a direction toward the plug 46 screw-fitted into the through hole 45b (see the valve body 59 shown by broken lines in
When the internal pressures PA1 and PA2 in the first fluid chamber 19 become higher than the internal pressures PB1 and PB2 in the second fluid chamber 20, the valve body 59 moves in a direction away from the plug 46. With this movement, the fluid in the first fluid chamber 19 passes through the orifice flow passage 34 and the fluid passage holes 60, and then flows to the second fluid chamber 20. In contrast, when the internal pressures PB1 and PB2 in the second fluid chamber 20 become higher than the internal pressures PA1 and PA2 in the first fluid chamber 19, the valve body 59 moves in a direction toward the plug 46. Since the valve body 59 closes the opening of the orifice flow passage 34 that is open toward the second end face 50, or closes the above intermediate flow passage (not illustrated), the fluid is blocked from flowing out from the second fluid chamber 20 to the first fluid chamber 19. In the manner as described above, the valve body 59 enables only the movement velocity of the movable cylinder 11 in the direction D1 to be selectively reduced in both the injection mode and the suction mode.
In a case where the amount of reduction in the movement velocity of the movable cylinder 11 is set individually for the direction D1 and the direction D2 in both the injection mode and the suction mode, the configuration as illustrated in
When the internal pressures PA1 and PA2 in the first fluid chamber 19 become higher than the internal pressures PB1 and PB2 in the second fluid chamber 20, the valve body 59′ moves in a direction toward the plug 46′. As illustrated in
The valve bodies 59 and 59′ in the present modification are also applicable to the first modification in which the plug 46a is fitted into the through hole 45a, and the second modification in which the plug 46b is fitted into the through hole 45. That is, the inner circumferential surface of the through hole 45b may be deformed to provide an intermediate flow passage communicating with the gaps 57 and 57a, and the valve bodies 59 and 59′ may be disposed so as to close this intermediate flow passage.
The valve bodies 59 and 59′ are not limited to having the configuration illustrated in
With reference to
For example, as illustrated in
The flow-rate adjustment valve 62 disposed in the short-circuit pipe 61 is opened at a predetermined throttle opening, so that similarly to the orifice flow passage 34, the above minute flow quantities q1 and q2 of fluid flows between the first flow-passage system and the second flow-passage system. With this configuration, when the movable cylinder 11 moves in the injection mode, the velocity of the movable cylinder 11 can be reduced, while the injection flow rate of the first nozzle 24 and the injection flow rate of the second nozzle 25 are prevented from being decreased. In contrast, when the movable cylinder 11 moves in the suction mode, the velocity of the movable cylinder 11 can be reduced, while the suction flow rate of the first nozzle 24 and the suction flow rate of the second nozzle 25 are prevented from being decreased.
Based on Equations (12) and (25) described above, the velocity reduction amount of the movable cylinder 11 is set according to the values of minute flow quantities q1 and q2 of the orifice flow passage 34, while the values of minute flow quantities q1 and q2 vary according to the flow-passage cross-sectional area of the orifice flow passage 34. Therefore, the velocity of the movable cylinder 11 can be reduced by a desired reduction amount by appropriately adjusting the throttle opening of the flow-rate adjustment valve 62.
With reference to
For example, as illustrated in
In a case where fluid flows between the fluid pressure source 41 and the target space E through the first flow-passage system, the second flow-rate adjustment valve 62b is opened at a predetermined throttle opening, so that similarly to the orifice flow passage 34, the above minute flow quantities q1 and q2 of fluid flows between the first flow-passage system and the second flow-passage system. In contrast, in a case where fluid flows between the fluid pressure source 41 and the target space E through the second flow-passage system, the first flow-rate adjustment valve 62a is opened at a predetermined throttle opening, so that similarly to the orifice flow passage 34, the above minute flow quantities q1 and q2 of fluid flows between the first flow-passage system and the second flow-passage system. With this configuration, when the movable cylinder 11 moves in the injection mode, the velocity of the movable cylinder 11 can be reduced, while the injection flow rate of the first nozzle 24 and the injection flow rate of the second nozzle 25 are prevented from being decreased. In contrast, when the movable cylinder 11 moves in the suction mode, the velocity of the movable cylinder 11 can be reduced, while the suction flow rate of the first nozzle 24 and the suction flow rate of the second nozzle 25 are prevented from being decreased.
Based on Equations (12) and (25) described above, the velocity reduction amount of the movable cylinder 11 is set according to the values of minute flow quantities q1 and q2 of the orifice flow passage 34, while the values of minute flow quantities q1 and q2 vary according to the flow-passage cross-sectional area of the orifice flow passage 34. Therefore, by appropriately adjusting the throttle opening of the first flow-rate adjustment valve 62a, the velocity reduction amount for the movement of the movable cylinder 11 in the direction D2 in the injection mode, and for the movement of the movable cylinder 11 in the direction D1 in the suction mode can be set to a desired value. In contrast, by appropriately adjusting the throttle opening of the second flow-rate adjustment valve 62b, the velocity reduction amount for the movement of the movable cylinder 11 in the direction D1 in the injection mode, and for the movement of the movable cylinder 11 in the direction D2 in the suction mode can be set to a desired value. With this configuration, in both the injection mode and the suction mode, the velocity reduction amount of the movable cylinder 11 can be set to different values between when the movable cylinder 11 moves in the direction D1 and when the movable cylinder 11 moves in the direction D2.
While the contents of the present invention have been specifically explained with reference to the preferred embodiments thereof, it is obvious that those skilled in the art may employ variously modified modes as described below based on the basic technical spirit and teachings of the present invention.
In the first to fourth embodiments described above, instead of forming the movable cylinder 11 in a straight tubular shape and forming the guides 13 and 14 into a straight line shape, these elements may be formed in the manner as described below. That is, the movable cylinder 11 may be formed in a circular tubular shape, and the guides 13 and 14 may extend outward from the piston 12 inserted in the movable cylinder 11 along the shape of the movable cylinder 11 through opposite opening end portions of the movable cylinder 11 and then extend in an arc-like curved shape. With this configuration, even when an injection or suction target is curved into an arc-like shape, it is still possible to inject or suction the fluid to the target.
In the movable cylinder 11, a single nozzle is provided for each of the fluid chambers 19 and 20 such that the nozzle communicates with each of the fluid chambers 19 and 20. However, a plurality of nozzles may be provided for each individual fluid chamber such that the nozzles communicate with each individual fluid chamber. Further, the nozzles 24 and 25 may be provided directly on the movable cylinder 11 not through the closing members 15 and 16 (not through the communication passages 22 and 23) such that the nozzles 24 and 25 communicate with the fluid chambers 19 and 20, respectively.
Instead of determining whether the movable cylinder 11 has reached the D1 regulated position or the D2 regulated position based on output signals from the first proximity detector 42 and the second proximity detector 43, the controller 44 may estimate the D1 regulated position and the D2 regulated position based on a count output of a timer.
The flow-passage switching valve 40 and the flow-rate adjustment valves 62, 62a, and 62b may be manually-operated valves that are manually operated by an operator, instead of being externally-controllable solenoid valves or electric-operated valves. In this case, the operator can visually confirm that the movable cylinder 11 has stopped at the D1 regulated position or the D2 regulated position, and can then operate the flow-passage switching valve 40. This makes it possible to omit the controller 44.
Instead of the outer openings 28 and 32 in the first guide 13, the outer openings 28 and 30 may be provided in the second guide 14, and accordingly the internal flow passages 26 and 30 may be formed to extend from these openings to the inner openings 27 and 31, respectively. In order to reduce the cross-sectional outer shape of the guides 13 and 14, either the outer opening 28 or the outer opening 32 may be provided in the second guide 14, and accordingly the internal flow passages 26 and 30 may be formed to extend from these openings to the inner openings 27 and 31, respectively.
In a case where the piston-cylinder mechanism 2 is located in, for example, a cylindrical filter to inject fluid to the inner circumferential surface of the filter or suction fluid from the inner circumferential surface of the filter through the nozzles 24 and 25, the piston-cylinder mechanism 2 is configured in the manner as described below. That is, in order that the movable cylinder 11 performs rotational motion along the outer circumferential surfaces of the piston 12 and the guides 13 and 14 in addition to the reciprocating motion described above, the piston 12 and the guides 13 and 14, and the through holes in the closing members 15 and 16 and the cylinder 11 are formed in a circular cross-sectional shape relative to each other.
The technical spirit explained in the first to fourth embodiments described above can be appropriately used in combination without causing any contradictions from the viewpoint of reducing the movement velocity of the movable cylinder 11 to a desired value. For example, it is assumed that there are circumstances where although the orifice flow passage 34 is drilled in the piston 12, the movement velocity of the movable cylinder 11 cannot be reduced to a desired value. For this assumption, an insufficient amount of reduction in the movement velocity can be compensated for by providing the flow-rate adjustment valve 62 in the short-circuit pipe 61 that short-circuits the first flow-passage system and the second flow-passage system, or by providing the flow-rate adjustment valves 62a and 62b respectively in the short-circuit pipes 61a and 61b connecting the pressure connection pipe 39 to the first external pipe 37 and to the second external pipe 38 so as to communicate with each other.
1, 1a, 1b, 1c fluid device, 11 movable cylinder, 12 piston, 13 first guide, 14 second guide, 15 first closing member, 16 second closing member, 19 first fluid chamber, 20 second fluid chamber, 24 first nozzle, 25 second nozzle, 26 first internal flow passage, 30 second internal flow passage, 34, 34′ orifice flow passage, 37 first external pipe, 38 second external pipe, 39 pressure connection pipe, 40 flow-passage switching valve, 41 fluid pressure source, 45, 45a, 45b, 45b′ through hole, 46, 46a, 46b, 46′ plug, 47 male thread, 48 female thread, 54, 54a conical face, 55, 55a opposed conical face, 57, 57a gap, 59, 59′ valve body, 61, 61a, 61b short-circuit pipe, 62, 62a, 62b flow-rate adjustment valve, E target space
Number | Date | Country | Kind |
---|---|---|---|
2021-000923 | Jan 2021 | JP | national |
Filing Document | Filing Date | Country | Kind |
---|---|---|---|
PCT/JP2021/048929 | 12/28/2021 | WO |