Patent Description:
Conventionally, a shock absorbing mechanism has been used in which a cushioning material made of a soft resin such as rubber or urethane or the like, or an oil damper or the like is attached to an end part of an air cylinder, to thereby cushion an impact at a stroke end. However, such a shock absorbing mechanism that mechanically mitigates shocks in the cylinder is limited in terms of the number of operations it can perform, and requires regular maintenance.

In order to resolve such incompatibility, in <CIT>, a speed controller (flow rate controller) is disclosed in which, by throttling the exhaust air that is discharged from the air cylinder in the vicinity of a stroke end, an operating speed of the air cylinder is reduced.

<CIT> discloses a gate valve device capable of restraining operation time in a target time, without generating a particle and reducing the service life of a mechanism part. The gate valve device is arranged on a side wall of a vacuum processing chamber, for opening-closing a carrying-in-and-out port for carrying in and out a glass substrate, and has a valve element for opening-closing the carrying-in-and-out port, an air cylinder for driving the valve element, and an air driving circuit controlling driving of the valve element so as to make a moving speed of the valve element different in response to the position of the valve element. A flow path takes pilot air from a flow path on the opposite side of the cylinder and is not connected to the first flow path.

In the pilot-operated check valve cartridge according to <CIT> a sleeve carries a check ball valve assembly to form a valve cartridge. The cartridge is insertable into a manifold to communicate with a control valve to extend or retract a piston cylinder in response to pneumatic or hydraulic pressure. The manifold may be contained within a piston end block. The cartridge is selectively removable from the manifold.

<CIT> relates to a power cylinder with self-contained flow or speed- control elements which are incorporated- into an integrated, interchangeable, and compact assembly to provide adjustable, constant control of piston velocity. Various fluid power cylinder designs include single rod end and double rod end types when operated either single or double acting whereby piston velocity is governed throughout the entire portion of the cylinder stroke whether it be push or pull.

However, such a conventional flow rate controller is an external component that is connected to ports of the air cylinder, which increases the number of component parts of the drive device of the air cylinder, and the device configuration of the drive device becomes complex. Further, the structure thereof is complicated, and a problem arises in that, when attempting to form the head cover and the rod cover integrally with the air cylinder, machining becomes difficult, and productivity is reduced.

The present invention has the object of providing an air cylinder, a head cover, and a rod cover, which enable the device configuration of a drive device to be simplified, and which are superior in terms of productivity.

According to the present invention there are provided a head cover comprising the features of claim <NUM> and a rod cover comprising the features of claim <NUM>.

The present invention also relates to an air cylinder comprising such a head cover and such a rod cover.

Preferred embodiments of the invention are evident from the dependent clams.

In accordance with the air cylinder, the head cover, and the rod cover according to the above-described aspects, the device configuration of the drive device can be simplified, and because the structure thereof is simplified, productivity is superior.

Hereinafter, a preferred embodiment of the present invention will be presented and described in detail below with reference to the accompanying drawings.

As shown in <FIG>, an air cylinder <NUM> is a double acting cylinder that is used in an automated equipment line or the like. The air cylinder <NUM> is equipped with a cylindrical cylinder tube <NUM>, a head cover <NUM> that seals a head side end part of the cylinder tube <NUM>, and a rod cover <NUM> that seals a rod side end part of the cylinder tube <NUM>. The cylinder tube <NUM>, the head cover <NUM>, and the rod cover <NUM> are connected in an axial direction by a plurality of connecting rods <NUM>.

As shown in <FIG>, in the interior of the cylinder tube <NUM>, there are provided a piston <NUM> that partitions a cylinder chamber 12c, and a piston rod <NUM> connected to the piston <NUM>. A head side flow rate controller <NUM> is connected to a head side pressure chamber 12a of the piston <NUM>, and a rod side flow rate controller 24A is connected to a rod side pressure chamber 12b of the piston <NUM>. The flow rate controller <NUM> is incorporated into the head cover <NUM>, and is connected to a head side port 14a. The flow rate controller 24A is incorporated into the rod cover <NUM>, and is connected to a rod side port 16a.

The head side flow rate controller <NUM> includes a first flow path <NUM> connecting the head side port 14a and the cylinder chamber 12c, and a second flow path <NUM> disposed in parallel with the first flow path <NUM>. A first flow rate adjustment part <NUM> is provided in the first flow path <NUM>. The first flow rate adjustment part <NUM> is made up of a throttle valve that variably throttles the flow rate of air passing through the first flow path <NUM>, and by primarily throttling the flow rate of exhaust air, suppresses an operating speed of the piston <NUM> in the vicinity of the stroke end.

A second flow rate adjustment part <NUM>, and a pilot check valve <NUM> are provided in the second flow path <NUM>. The second flow rate adjustment part <NUM> is a throttle valve, and can variably adjust the flow rate of air passing through the second flow path <NUM>. The pilot check valve <NUM> is a check valve through which the passage of exhaust air is switched depending on the pressure of the pilot air, and includes an inlet 38a, an outlet 38b, and a pilot port 38c. The inlet 38a is connected to the head side port 14a side of the second flow path <NUM>, and the outlet 38b is connected to the cylinder chamber 12c side of the second flow path <NUM>. When the pressure of the pilot air falls below a predetermined value, the pilot check valve <NUM> operates as a check valve that allows air to pass from the inlet 38a toward the outlet 38b, while preventing the passage of air in the opposite direction. Further, when the pressure of the pilot air becomes greater than or equal to the predetermined value, the pilot check valve <NUM> allows the air to pass in both directions from the inlet 38a toward the outlet 38b, and vice versa.

The flow rate controller <NUM> further includes a third flow path <NUM> connecting the head side port 14a and the cylinder chamber 12c, and a pilot air flow path <NUM> connecting the head side port 14a and the pilot port 38c of the pilot check valve <NUM>. A check valve <NUM> is disposed in the third flow path <NUM>. The check valve <NUM> is connected in a direction that allows passage of air flowing from the head side port 14a toward the cylinder chamber 12c, while preventing the passage of air in the opposite direction. The third flow path <NUM> and the check valve <NUM> allow high pressure air to pass freely toward the cylinder chamber 12c. The third flow path <NUM> and the check valve <NUM> need not necessarily be provided independently as shown in the drawings, but may be an integrated member with the throttle valve of the first flow rate adjustment part <NUM> or the throttle valve of the second flow rate adjustment part <NUM>, in the form of a check valve equipped throttle valve.

A third flow rate adjustment part <NUM>, which is capable of variably adjusting the flow rate of the pilot air supplied to and discharged from the pilot check valve <NUM>, is provided in the pilot air flow path <NUM>. The third flow rate adjustment part <NUM> includes a throttle valve 42a, and a check valve 42b which is connected in parallel with the throttle valve 42a. The check valve 42b is connected in a direction that allows air to pass from the head side port 14a toward the pilot check valve <NUM>, while preventing the passage of air in the opposite direction, and quickly supplies the pilot air to the pilot check valve <NUM>. The throttle valve 42a is capable of variably adjusting the flow rate of the pilot air discharged through the pilot air flow path <NUM>, and determines a timing at which the operation of the pilot check valve <NUM> is switched. The third flow rate adjustment part <NUM> can be configured in the form of a check valve equipped throttle valve in which the throttle valve 42a and the check valve 42b are integrated.

The head side flow rate controller <NUM> is configured in the manner described above. On the other hand, since the rod side flow rate controller 24A is configured in substantially the same manner as the head side flow rate controller <NUM>, constituent elements thereof which are the same as those of the head side flow rate controller <NUM> are designated by the same reference numerals, and detailed description thereof is omitted. However, the constituent elements of the rod side flow rate controller 24A are indicated by appending the letter "A" at the end of each of the reference numerals, in order to distinguish them from the constituent elements of the head side flow rate controller <NUM>.

Hereinafter, a description will be given concerning a specific configuration of the head cover <NUM> and the rod cover <NUM> in which the flow rate controllers <NUM> and 24A are incorporated.

As shown in <FIG>, the rod cover <NUM> includes a main body portion 60A formed in the shape of a flat rectangular parallelepiped. An insertion member <NUM> through which the piston rod <NUM> is inserted is provided at a central part of an outer end surface 60a of the main body portion 60A, and connecting holes 22a for fixing the connecting rods <NUM> are provided at the four corners of the outer end surface 60a of the main body portion 60A. The connecting holes 22a extend in the axial direction of the piston rod <NUM> and penetrate through the main body portion 60A. The throttle valves, which constitute a first flow rate adjustment part 28A, a second flow rate adjustment part 32A, and a third flow rate adjustment part 42A, are provided together with the rod side port 16a on an upper surface 60b of the rod cover <NUM>.

As shown in <FIG>, an annular shaped cylinder tube mounting groove <NUM> in which the cylinder tube <NUM> is mounted is provided on an inner end surface 60c of the main body portion 60A of the rod cover <NUM>, and an inner side of the cylinder tube mounting groove <NUM> faces an inner side of the rod side pressure chamber 12b. An insertion hole 20a through which the piston rod <NUM> is inserted is formed in a central portion of the cylinder tube mounting groove <NUM>, and a first flow path 26A and valve holes 59a and 59b open circumferentially around the piston rod <NUM>. A check valve 36A is mounted in the valve hole 59a, and a pilot check valve 38A is mounted in the valve hole 59b.

As shown in <FIG>, the first flow rate adjustment part 28A and the second flow rate adjustment part 32A are arranged on the cylinder tube <NUM> side of the rod side port 16a, and the third flow rate adjustment part 42A is arranged on the lateral side of the rod side port 16a. Further, the pilot check valve 38A is disposed in the interior of the main body portion 60A between the rod side port 16a and the third flow rate adjustment part 42A.

Ends of the first flow path 26A, a second flow path 30A, a third flow path 34A, and a pilot air flow path 40A open, respectively, at the rod side port 16a. As shown in <FIG>, the first flow path 26A opens on a side portion of the rod side port 16a, and extends toward an inlet 28a of the first flow rate adjustment part 28A. The first flow rate adjustment part 28A is a throttle valve provided in a valve hole 59c, and includes a needle <NUM> that variably closes a flow path between the inlet 28a that opens on a side portion of the valve hole 59c and an outlet 28b that opens on a bottom portion of the valve hole 59c. The needle <NUM> is fixed in the valve hole 59c by a screw mechanism, and when the needle <NUM> is rotated and the needle <NUM> is made to project toward the outlet 28b, the flow path is narrowed. A portion of the first flow path 26A on the outlet side extends toward and opens on the inner end surface 60c.

As shown in <FIG>, the second flow path 30A is connected via the second flow rate adjustment part 32A to an inlet 38a of the pilot check valve 38A. As shown in <FIG>, the second flow rate adjustment part 32A includes a valve main body <NUM> provided in a valve hole 59d that opens on the upper surface 60b and communicates with the second flow path 30A. The valve main body <NUM> is mounted in the valve hole 59d by a screw mechanism 94a, and by rotating the valve main body <NUM>, the valve main body <NUM> is made to project toward the second flow path 30A, or alternatively, the valve main body <NUM> is made to retract away from the second flow path 30A, whereby the flow rate of the second flow path 30A can be variably adjusted.

As shown in <FIG> and <FIG>, the third flow path 34A opens on a lower end of the rod side port 16a, extends toward the inner end surface 60c of the main body portion 60A, and is connected to the check valve 36A. The check valve 36A is inserted into the valve hole 59a that opens on the inner end surface 60c, and includes a valve element <NUM>, a supporting body <NUM> that is fitted into the valve hole 59a and thereby supports the valve element <NUM>, and a spring <NUM> connecting the valve element <NUM> and the supporting body <NUM>. An inlet 90a having a reduced diameter is formed on a rear side of the valve hole 59a, and the valve element <NUM> is arranged so as to close the inlet 90a. The spring <NUM> is arranged between the valve element <NUM> and the supporting body <NUM>, and biases the valve element <NUM> toward the inlet 90a side. The air flowing from the inlet 90a side flows into the valve hole 59a by pressing the valve element <NUM> toward the supporting body <NUM> side against the biasing force of the spring <NUM>, and flows via an opening 86a into the rod side pressure chamber 12b. In the case that the pressure on the side of the rod side pressure chamber 12b is high, since the valve element <NUM> is pressed against the inlet 90a, the check valve 36A prevents the exhaust air of the rod side pressure chamber 12b from passing.

As shown in <FIG>, the pilot air flow path 40A extends from the rod side port 16a toward an inlet 43a of the third flow rate adjustment part 42A, and is connected via the third flow rate adjustment part 42A to the pilot port 38c. The third flow rate adjustment part 42A is disposed in a valve hole 59e that opens on the upper surface 60b and communicates with the pilot air flow path 40A. The third flow rate adjustment part 42A is a check valve equipped throttle valve, and includes a flow path member 95a constituting an inner side flow path and an outer side flow path, a needle 95b capable of variably adjusting the cross-sectional area of the inner side flow path, and a seal member 95c provided in the outer side flow path. The seal member 95c is an elastic member having a substantially V-shaped cross section with a concave portion directed toward an outlet 43b, and prevents the passage of air flowing in a reverse direction from the outlet 43b toward the inlet 43a in the outer side flow path.

As shown in <FIG>, one end of the pilot air flow path 40A communicates with the pilot port 38c of the pilot check valve 38A. The pilot check valve 38A is provided in the valve hole 59b that is formed by penetrating through the main body portion 60A in the axial direction and has a circular cross section. The valve hole 59b includes a piston chamber <NUM> formed on the outer end surface 60a side, a check valve accommodating portion <NUM> formed on the inner end surface 60c side, and an intermediate portion <NUM> formed between the piston chamber <NUM> and the check valve accommodating portion <NUM>. An end part of the piston chamber <NUM> on the outer end surface 60a side is sealed by a cap <NUM>. The pilot air flow path 40A opens as the pilot port 38c in the piston chamber <NUM> in the vicinity of the cap <NUM>. An air vent hole <NUM> opens in the vicinity of an end part of the piston chamber <NUM> on the inner end surface 60c side. The air vent hole <NUM> opens on the upper surface 60b of the main body portion 60A.

The intermediate portion <NUM> is formed with an inner diameter that is smaller than that of the piston chamber <NUM> and the check valve accommodating portion <NUM>, and includes, at a boundary portion between the intermediate portion <NUM> and the check valve accommodating portion <NUM>, a reduced diameter portion 66a formed by reducing the diameter of the intermediate portion <NUM>. A pilot piston <NUM> is arranged in the piston chamber <NUM> and the intermediate portion <NUM>. The pilot piston <NUM> includes a piston member 76a that slides inside the piston chamber <NUM>. The piston member 76a partitions the piston chamber <NUM> into a portion communicating with the pilot air flow path 40A and a portion communicating with the air vent hole <NUM>, and receives the pressure of the pilot air from the pilot air flow path 40A to generate a driving force in a rightward direction as shown in the drawing. When the pressure of the pilot air increases, the pilot piston <NUM> projects toward the inner end surface 60c side as shown in <FIG>.

As shown in <FIG>, a guide member 76b is formed to project from the piston member 76a toward the intermediate portion <NUM> side. The guide member 76b is formed with a diameter that is slightly smaller than the inner diameter of the intermediate portion <NUM>, and slides along the intermediate portion <NUM>. A packing 76d in order to prevent leakage of air is provided on an outer circumferential part of the guide member 76b. A rod member 76c extends from an end part of the guide member 76b on the check valve accommodating portion <NUM> side. The rod member 76c is formed with a diameter that is smaller than that of the reduced diameter portion 66a of the intermediate portion <NUM>, and is separated from the inner circumferential surfaces of the intermediate portion <NUM> and the reduced diameter portion 66a.

A valve element <NUM>, a supporting body <NUM> that supports the valve element <NUM>, and a return spring <NUM> that biases the valve element <NUM> are provided in the check valve accommodating portion <NUM>. The supporting body <NUM> is fitted into an end part of the check valve accommodating portion <NUM> on the inner end surface 60c side. A cylindrical shaft hole 72a is provided in a central portion of the supporting body <NUM>, and a shaft portion 70a of the valve element <NUM> is inserted into the shaft hole 72a. Further, an opening 72b is provided on an outer circumferential portion of the supporting body <NUM>, and an inner side of the check valve accommodating portion <NUM> and the rod side pressure chamber 12b are capable of communicating through the opening 72b. The valve element <NUM> includes a closing portion 70b which is a portion thereof that faces the reduced diameter portion 66a and is enlarged in diameter in a disk-like shape, and the shaft portion 70a extends from the closing portion 70b toward the supporting body <NUM> side. The closing portion 70b is biased by the return spring <NUM> toward the reduced diameter portion 66a side, and the closing portion 70b covers and closes the reduced diameter portion 66a.

In a state in which the pressure of the pilot air is not acting, as shown in the drawing, the pilot piston <NUM> of the pilot check valve 38A is biased toward the cap <NUM> side by the elastic force of the return spring <NUM>. In such a state, when the high pressure air flows in from the intermediate portion <NUM>, since the closing portion 70b is pressed by the high pressure air, the valve element <NUM> is separated away from the reduced diameter portion 66a and then allows passage of the air flowing toward the rod side pressure chamber 12b through the second flow path 30A. On the other hand, when the pressure of the exhaust air in the rod side pressure chamber 12b increases, the closing portion 70b is biased toward the reduced diameter portion 66a side, and therefore, the valve element <NUM> prevents the exhaust air from passing.

Further, as shown in <FIG>, when the pressure of the pilot air is greater than or equal to the predetermined value, the pilot piston <NUM> is displaced toward the check valve accommodating portion <NUM> side. In such a state, by the rod member 76c of the pilot piston <NUM> projecting toward the check valve accommodating portion <NUM> side, the closing portion 70b of the valve element <NUM> is retained in a state of being separated away from the reduced diameter portion 66a. Therefore, the pilot check valve 38A allows the air to pass not only in a direction from the inlet 38a toward the outlet 38b, but also in a direction opposite thereto.

The rod cover <NUM> is configured in the manner described above, and hereinafter, a description will be given concerning the head cover <NUM>. As shown in <FIG>, the head cover <NUM> is equipped with a rectangular parallelepiped shaped main body portion <NUM> that is flat in the axial direction. The connecting holes 22a open on an outer end surface 60a of the main body portion <NUM>. Further, the head side port 14a, the first flow rate adjustment part <NUM>, the second flow rate adjustment part <NUM>, and the third flow rate adjustment part <NUM> are exposed on an upper surface 60b of the main body portion <NUM>, and an air vent hole <NUM> opens thereon.

As shown in <FIG>, a cylinder tube mounting groove <NUM> is formed on an inner end surface 60c of the main body portion <NUM>, and openings of the check valve <NUM>, the pilot check valve <NUM>, and the first flow path <NUM> are provided on the inner side thereof.

As shown in <FIG>, in the head cover <NUM>, the pilot check valve <NUM> is disposed closer to the center of the main body portion <NUM> of the head cover <NUM>, and the third flow rate adjustment part <NUM> is arranged in an overlapping manner with the upper surface 60b side of the pilot check valve <NUM>. Consequently, the pathway of the pilot air flow path <NUM> is made simpler in structure. Note that the cross-sectional shapes along the line XB-XB of the first flow path <NUM>, the third flow path <NUM>, the first flow rate adjustment part <NUM>, and the check valve <NUM> are the same as the cross-sectional shapes of the first flow path 26A, the third flow path 34A, the first flow rate adjustment part 28A, and the check valve 36A of the rod cover <NUM> shown in <FIG>. Further, the cross-sectional shapes along the line XA-XA of <FIG> of the second flow path <NUM> and the second flow rate adjustment part <NUM> are the same as the cross sectional shapes shown in <FIG>.

As shown in <FIG>, the layout of the head cover <NUM> differs from the layout of the rod cover <NUM> in that the pilot air flow path <NUM> opens on the upper end of the piston chamber <NUM>, and the second flow path <NUM> opens on the upper end of the intermediate portion <NUM>,. The other structural features of the pilot check valve <NUM> that is formed in the head cover <NUM> are the same as those of the pilot check valve 38A shown in <FIG>, and since the same structural elements thereof are designated by the same reference numerals, detailed description of such features is omitted herein.

The air cylinder <NUM>, the head cover <NUM>, and the rod cover <NUM> according to the present embodiment are configured in the manner described above. Hereinafter, a description will be given concerning operations and actions thereof.

As shown in <FIG>, at a time when the air cylinder <NUM> is used, a drive device <NUM> is connected thereto, which includes a high pressure air supply source <NUM>, exhaust ports <NUM>, and an operation switching valve <NUM> that connects the high pressure air supply source <NUM> and the exhaust port <NUM> to the head side port 14a and the rod side port 16a in a switchable manner. The operation switching valve <NUM> is a <NUM>-port valve that is switched electrically, and includes first through fifth ports 56a to 56e. The first port 56a is connected to the head side port 14a, and the second port 56b is connected to the rod side port 16a. Further, the third port 56c and the fifth port 56e are connected to the exhaust ports <NUM>, and the fourth port 56d is connected to the high pressure air supply source <NUM>. In a first position shown in <FIG>, in the operation switching valve <NUM>, by placing the first port 56a and the fourth port 56d in communication with each other, and placing the second port 56b and the fifth port 56e in communication with each other, the high pressure air supply source <NUM> is connected to the head side port 14a, the exhaust port <NUM> is connected to the rod side port 16a, and the piston <NUM> performs an operating stroke.

As shown by the arrow A, the high pressure air from the high pressure air supply source <NUM> flows from the head side port 14a to the head side flow rate controller <NUM>. In the head side flow rate controller <NUM>, the high pressure air flows to the head side pressure chamber 12a through the first flow path <NUM>, the second flow path <NUM>, and the third flow path <NUM>. In this case, as shown by the arrow A, the high pressure air is supplied to the head side pressure chamber 12a in a free flowing manner through the third flow path <NUM> and the check valve <NUM>, without passing through the throttle valve.

Further, the pilot air is supplied from the pilot port 38c of the pilot check valve <NUM> through the pilot air flow path <NUM> and the check valve 42b of the third flow rate adjustment part <NUM>. Consequently, as shown in <FIG>, in the pilot check valve <NUM> on the head side, the rod member 76c of the pilot piston <NUM> projects toward the check valve accommodating portion <NUM> side, and allows flow in both directions.

Accompanying the operating stroke of the piston <NUM>, as shown by the arrow B, the exhaust air from the rod side pressure chamber 12b is discharged through the rod side flow rate controller 24A. Since the check valve 36A does not allow the exhaust air to pass, as shown by the arrow B1, the exhaust air is discharged through the first flow path 26A, and as shown by the arrow B2, the exhaust air is discharged through the second flow path 30A. Until the middle of the operating stroke, the pilot check valve 38A of the second flow path 30A maintains the pressure of the pilot air that was accumulated in the piston chamber <NUM> in the previous return stroke. Therefore, as shown in <FIG>, since the pilot piston <NUM> continues to cause the valve element <NUM> to separate away from the reduced diameter portion 66a, the pilot check valve 38A allows the exhaust air to pass. Therefore, in <FIG>, as shown by the arrow B1 + B2, the exhaust air is discharged at a predetermined flow rate (first control flow) through the first flow path 26A and the second flow path 30A. The operating speed of the piston <NUM> is limited due to the flow rate of the exhaust air.

Further, in the operating stroke, as shown by the arrow C2, the pilot air of the pilot check valve 38A gradually flows out through the pilot air flow path 40A and the third flow rate adjustment part 42A. Accompanying outward flowing of the pilot air, the pressure of the pilot air in the pilot check valve 38A gradually decreases.

Then, at a predetermined timing when the piston <NUM> approaches the stroke end, the pilot piston <NUM> of the pilot check valve 38A returns to the initial position as shown in <FIG>, and the reduced diameter portion 66a is closed by the valve element <NUM>. Consequently, as shown by the arrow B1 in <FIG>, the exhaust air is switched to a second control flow of flowing through the first flow path 26A. During the second control flow, since the flow rate of the exhaust air is further throttled by the first flow rate adjustment part 28A than in the first control flow, the operating speed of the piston <NUM> is restricted. Consequently, an impact at the stroke end of the piston <NUM> can be suppressed.

Thereafter, the operation switching valve <NUM> is switched from the first position to the second position, whereby the high pressure air supply source <NUM> is connected to the rod side port 16a, the exhaust port <NUM> is connected to the head side port 14a, and a return stroke is initiated. The operations in the return stroke simply involve a switching of places in the operating stroke between the head side flow rate controller <NUM> and the rod side flow rate controller 24A, and since the operations in the return stroke and the operations in the operating stroke are substantially the same, a description of such operations will be omitted.

The air cylinder <NUM>, the head cover <NUM>, and the rod cover <NUM> of the present embodiment realize the following advantageous effects.

The air cylinder <NUM> according to the present embodiment is equipped with the cylinder tube <NUM> in which the cylinder chamber 12c is formed, the head cover <NUM> that closes one end of the cylinder tube <NUM>, the rod cover <NUM> that closes the other end of the cylinder tube <NUM>, the piston <NUM> that slides in the cylinder chamber 12c, the piston rod <NUM> having one end connected to the piston <NUM>, the ports 14a and 16a provided respectively in the head cover <NUM> and the rod cover <NUM>, and the flow rate controller <NUM> incorporated into the head cover <NUM> and the rod cover <NUM>, wherein the flow rate controller <NUM> includes the first flow paths <NUM> and 26A that allow communication between the ports 14a and 16a and the cylinder chamber 12c, the first flow rate adjustment parts <NUM> and 28A disposed in the first flow paths <NUM> and 26A, the second flow paths <NUM> and 30A disposed in parallel with the first flow paths <NUM> and 26A, the second flow rate adjustment parts <NUM> and 32A disposed in the second flow paths <NUM> and 30A, the pilot check valves <NUM> and 38A disposed in series with the second flow rate adjustment parts <NUM> and 32A in the second flow paths <NUM> and 30A, and the third flow rate adjustment parts <NUM> and 42A that supply and discharge pilot air to and from the pilot check valves <NUM> and 38A, and wherein, depending on the pressure of the pilot air, the pilot check valves <NUM> and 38A switch between a state allowing passage of the exhaust air discharged from the cylinder chamber 12c, and a state preventing the passage of the exhaust air, and the third flow rate adjustment parts <NUM> and 42A are connected to the respective ports 14a, 16a.

According to the above-described configuration, since the pilot check valves <NUM> and 38A, which are of a simple structure, are used in order to switch the control flow of the exhaust air, a switching valve in which a shuttle valve or a three-way valve is used becomes unnecessary, and the internal structure is simplified. Further, since constituent members, for which precision is required, such as sleeves and spools that constitute a shuttle valve or a three-way valve are rendered unnecessary, grinding or polishing and surface treatment requiring a number of production steps are rendered unnecessary, and manufacturing can be carried out at a low cost.

The above-described air cylinder <NUM> may further comprise the check valves <NUM> and 36A that are disposed in parallel with the first flow rate adjustment parts <NUM> and 28A, and allow passage of air flowing from the ports 14a and 16a toward the cylinder chamber 12c. In accordance with such a configuration, the high pressure air can be supplied to the cylinder chamber 12c in a free flowing manner, and the air cylinder <NUM> can be operated at high speed.

In the above-described air cylinder <NUM>, the third flow rate adjustment parts <NUM> and 42A may be equipped with the throttle valve 42a, and the check valve 42b that is disposed in parallel with the throttle valve 42a and allows passage of air flowing toward the pilot port 38c.

The head cover <NUM> according to the present embodiment is the head cover <NUM> for the air cylinder <NUM> that is configured to cover a head side end part of the cylinder tube <NUM>, the head cover comprising the head side port 14a and the flow rate controller <NUM>.

The rod cover <NUM> according to the present embodiment is the rod cover <NUM> for the air cylinder <NUM> that is configured to cover a rod side end part of the cylinder tube <NUM>, the rod cover comprising the rod side port 16a and the flow rate controller 24A.

Claim 1:
A head cover (<NUM>) for an air cylinder (<NUM>) that is configured to cover
a head side end part of a cylinder tube (<NUM>), the head cover comprising:
a port (14a); and
a flow rate controller (<NUM>),
wherein the flow rate controller includes:
a first flow path (<NUM>) configured to communicate with the port and a cylinder chamber (12c) of the air cylinder;
a first flow rate adjustment part (<NUM>) disposed in the first flow path;
a second flow path (<NUM>) disposed in parallel with the first flow path;
a second flow rate adjustment part (<NUM>) disposed in the second flow path;
a pilot check valve (<NUM>) disposed in the second flow path, and connected in series with the second flow rate adjustment part; and
a third flow rate adjustment part (<NUM>) configured to supply and discharge pilot air to and from the pilot check valve,
wherein, depending on a pressure of the pilot air, the pilot check valve switches between a state allowing passage of exhaust air discharged from the cylinder chamber, and a state preventing the passage of the exhaust air, and
the third flow rate adjustment part is connected to the port (14a).