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.

To provide 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, <CIT> discloses a gate valve device 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 The device 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.

However, such a conventional flow rate controller is formed with a large number of component parts. Further, in the case that a three-way valve is used as a member for switching a throttled state of the exhaust air, a problem arises in that component parts requiring a number of production steps, such as a spool or the like on which grinding or polishing is needed, become necessary, and the flow rate controller cannot be manufactured at a low cost.

The present invention has the object of providing a flow rate controller and a drive device equipped with the flow rate controller, which can simplify the device configuration and can be manufactured easily.

The problem is solved by a flow rate controller according to claim <NUM> and a drive device comprising the same according to claim <NUM>.

In accordance with the flow rate controller and the drive device comprising the same according to the above-described aspects, the device configuration is simplified, and manufacturing becomes easy to perform.

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 cylindrically shaped cylinder tube <NUM>. 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 port <NUM> is provided in a head side pressure chamber 12a, and a rod side port 18A is provided in a rod side pressure chamber 12b.

A drive device <NUM> is connected to the head side port <NUM> and the rod side port 18A. The drive device <NUM> is equipped with a head side flow rate controller <NUM> connected to the head side port <NUM>, a rod side flow rate controller 22A connected to the rod side port 18A, a high pressure air supply source <NUM>, exhaust ports <NUM>, and an operation switching valve <NUM>.

As shown in <FIG>, the head side flow rate controller <NUM> has a flat box-shaped housing <NUM>. On a front surface 30a of the housing <NUM>, there are provided a cylinder side port <NUM> connected to the head side port <NUM> of the air cylinder <NUM>, a valve side port <NUM> connected to the operation switching valve <NUM>, and a second throttle valve <NUM> that sets a stroke speed of the air cylinder <NUM>. Further, on an upper surface 30b of the housing <NUM>, there are provided a first throttle valve <NUM> for adjusting a degree to which an operating speed of the piston <NUM> is limited, and a third throttle valve <NUM> that sets a timing at which regulation of the operating speed of the piston <NUM> is initiated. A connecting member 32b is provided on the cylinder side port <NUM>, and a connecting member 34b is provided on the valve side port <NUM>.

As shown by the dashed lines in <FIG>, in the interior of the housing <NUM>, there are provided a first flow path <NUM>, a pilot air flow path <NUM>, and a pilot check valve <NUM>. Hereinafter, with reference to the cross-sectional views of <FIG>, a description will be given concerning the internal structure of the housing <NUM>.

As shown in <FIG>, the valve side port <NUM> is disposed in a port forming hole 34a provided in the vicinity of a first side surface 30c of the housing <NUM>. The port forming hole 34a opens on the front surface 30a of the housing <NUM>, and is formed toward a rear surface 30e. The connecting member 34b, which is provided in order for a pipe to be connected thereto, is mounted on the front surface 30a of the port forming hole 34a. The first flow path <NUM> and the pilot air flow path <NUM> open on an end part of the port forming hole 34a on the rear surface 30e side.

As shown in <FIG>, the first flow path <NUM> and a second flow path <NUM> are flow paths that connect the valve side port <NUM> and the cylinder side port <NUM>, and are arranged in parallel. As shown in <FIG>, the first flow path <NUM> includes a first hole portion 42a that extends linearly from the port forming hole 34a toward a second side surface 30d, and a second hole portion 42b that is bent and extends from the first hole portion 42a toward the cylinder side port <NUM>. Further, an end part of the first hole portion 42a on the second side surface 30d side communicates, as a portion of the second flow path <NUM>, with the second throttle valve <NUM>.

The second throttle valve <NUM> is provided in a valve hole <NUM> formed between the valve side port <NUM> and the cylinder side port <NUM>. The valve hole <NUM> opens on a front surface side of the housing <NUM>, and extends toward the rear surface 30e. The first hole portion 42a opens on a side part of the valve hole <NUM>, and an end part of the valve hole <NUM> on the rear surface 30e side communicates with an inlet 48a of the pilot check valve <NUM>, as will be discussed later.

The second throttle valve <NUM> is a check valve equipped throttle valve in which a throttle valve 38a and a check valve 38b are formed integrally, and as shown in <FIG>, the throttle valve 38a and the check valve 38b are arranged in parallel. As shown in <FIG>, the second throttle valve <NUM> includes a tubular flow path member <NUM>, a rod-shaped member <NUM> arranged on an inner circumferential part of the flow path member <NUM>, a knob portion <NUM> joined to an end part of the rod-shaped member <NUM>, and a backflow prevention sealing member <NUM> mounted on an outer circumferential part of the flow path member <NUM>. The flow path member <NUM> is fitted into the inlet side of the valve hole <NUM>, is smaller in diameter at the rear side part thereof than the inlet side part thereof, and divides the valve hole <NUM> into an inner side flow path 52b on an inner circumferential side of the flow path member <NUM>, and an outer side flow path 54a on an outer side of the flow path member <NUM>. The inner side flow path 52b has an end part which opens toward an inner side of the valve hole <NUM>, and includes, on the side part thereof, an opening 52a which communicates with the first hole portion 42a. The outer side flow path 54a is formed as a gap between an outer circumference of the flow path member <NUM> and the valve hole <NUM>. Air from the first hole portion 42a is capable of flowing through two flow paths, i.e., the inner side flow path 52b and the outer side flow path 54a.

The rod-shaped member <NUM> of the second throttle valve <NUM> is arranged so as to be capable of advancing and retracting inside the inner side flow path 52b, via a screw mechanism 58a. Together with the knob portion <NUM>, the rod-shaped member <NUM> can be rotated, and by rotating the knob portion <NUM>, the cross-sectional area of the inner side flow path 52b is variably adjusted, thereby constituting the throttle valve 38a.

Further, the backflow prevention sealing member <NUM> is disposed in the outer side flow path 54a. The backflow prevention sealing member <NUM> is an annular sealing member that is mounted on the outer circumference of the flow path member <NUM>, and is formed with a substantially V-shaped cross section having a concave portion formed on a rear side thereof. The backflow prevention sealing member <NUM> is elastically deformed such that the outer circumferential portion thereof is reduced in diameter to allow air flowing from the first hole portion 42a toward the inner side of the valve hole <NUM> to pass in a free flowing manner. Further, for the air flowing from the inner side of the valve hole <NUM> toward the first hole portion 42a, the outer circumferential portion of the backflow prevention sealing member <NUM> comes into close contact with the inner circumferential surface of the valve hole <NUM> to prevent the passage of the air through the outer side flow path 54a. Therefore, the air flowing from the inner side of the valve hole <NUM> toward the first hole portion 42a is capable of passing only through the inner side flow path 52b, and the air flows at a flow rate that is regulated by the rod-shaped member <NUM>.

The pilot check valve <NUM> is provided on the rear surface 30e side of the valve hole <NUM>. The pilot check valve <NUM> is disposed in a through hole <NUM> that penetrates from the first side surface 30c to the second side surface 30d. The through hole <NUM> is closed by a cap <NUM> on the first side surface 30c side, and is closed by a cap <NUM> on the second side surface 30d side. A piston chamber 60a, an intermediate portion 60b, and a check valve accommodating portion 60c are formed on the inner side of the cap <NUM> and the cap <NUM>. The piston chamber 60a is a vacant chamber having a circular cross section, and the pilot air flow path <NUM> opens in the form of a pilot port 48c in the vicinity of the cap <NUM>. Further, an air vent hole <NUM>, which is opened to the atmosphere, opens in the vicinity of an end part of the piston chamber 60a on the intermediate portion 60b side. Furthermore, the intermediate portion 60b, which is formed with an inner diameter smaller than that of the piston chamber 60a, is formed on the second side surface 30d side of the piston chamber 60a.

A pilot piston <NUM>, which is displaced in the axial direction of the through hole <NUM> according to the pressure of the pilot air, is arranged in the piston chamber 60a and the intermediate portion 60b. The pilot piston <NUM> includes a piston portion 66a that slides in the piston chamber 60a, a guide portion 66b that extends from the piston portion 66a toward the intermediate portion 60b, and a rod portion 66c that projects toward a distal end side (the second side surface 30d side) of the guide portion 66b. The piston portion 66a partitions the piston chamber 60a into a region that communicates with the pilot air flow path <NUM>, and a region that communicates with the air vent hole <NUM>. A return spring <NUM> is arranged in the piston chamber 60a on the intermediate portion 60b side of the piston portion 66a, and in the case that the pilot air is not acting, the pilot piston <NUM> is biased toward the cap <NUM> side by the elastic force of the return spring <NUM>.

The guide portion 66b is formed with an inner diameter that allows the guide portion 66b to be inserted into the intermediate portion 60b, and is configured to slide while being guided by the intermediate portion 60b. The rod portion 66c projects from a distal end of the guide portion 66b. The rod portion 66c is formed with an outer diameter that is smaller than an inner diameter of the intermediate portion 60b, and forms a flow path through which air can pass, between the rod portion 66c and an inner circumferential surface of the intermediate portion 60b. A reduced diameter portion 60d, which is formed by reducing the inner diameter of the intermediate portion 60b, is formed on an end part of the intermediate portion 60b on the second side surface 30d side. The above-described rod portion 66c is formed with a diameter that is smaller than an inner diameter of the reduced diameter portion 60d, and the rod portion 66c is therefore capable of projecting toward the check valve accommodating portion 60c side. Further, the rod portion 66c is arranged so that a distal end portion thereof abuts against a later-described valve element <NUM> in the check valve accommodating portion 60c.

The check valve accommodating portion 60c is formed on the second side surface 30d side of the intermediate portion 60b. The check valve accommodating portion 60c is a vacant chamber having a circular cross section and formed with an inner diameter greater than that of the intermediate portion 60b, and the valve element <NUM> that constitutes the check valve is arranged in the interior thereof. The valve element <NUM> includes a disk-shaped closing portion 70a formed with a diameter capable of closing the reduced diameter portion 60d of the intermediate portion 60b, and a shaft portion 70b projecting from the closing portion 70a toward the cap <NUM> side. The closing portion 70a is covered with an elastic member that is superior in terms of its adhesive property. The shaft portion 70b is inserted into a tubular receiving portion 62a provided so as to project from the cap <NUM>, and the valve element <NUM> is supported by the cap <NUM> so as to be capable of being displaced in the axial direction of the through hole <NUM>. Further, a return spring <NUM> is disposed between the valve element <NUM> and the cap <NUM>, and the valve element <NUM> is biased toward the reduced diameter portion 60d by the elastic force of the return spring <NUM>. The second flow path <NUM> opens in the form of an outlet 48b on a side part of the check valve accommodating portion 60c. The second flow path <NUM> extends toward the front surface 30a, and communicates with a port forming hole 32a of the cylinder side port <NUM>.

When the air attempts to flow in a reverse direction from the outlet 48b toward the inlet 48a, the valve element <NUM> is biased due to the pressure of the air so as to close the reduced diameter portion 60d, and prevents the air from flowing in reverse. However, as shown in <FIG>, in the case that the rod portion 66c of the pilot piston <NUM> projects into the check valve accommodating portion 60c due to the pressure of the pilot air, the valve element <NUM> is maintained in a state of being separated away from the reduced diameter portion 60d, and allows passage of the air that flows in the reverse direction from the outlet 48b toward the inlet 48a.

Meanwhile, as shown in <FIG>, the second hole portion 42b of the first flow path <NUM> extends toward the second side surface 30d side in a bypassing manner around the valve hole <NUM> of the second throttle valve <NUM>, and after passing through the first throttle valve <NUM>, merges with a portion of the first flow path <NUM> in the vicinity of the cylinder side port <NUM>. The first throttle valve <NUM> is disposed in a valve hole 36a which is formed from the upper surface 30b side. The second hole portion 42b opens in the form of an inlet 36b of the first throttle valve <NUM> on a lower end part of the valve hole 36a, and the second hole portion 42b opens in the form of an outlet 36c on a side part of the valve hole 36a. The first throttle valve <NUM> is equipped with a needle <NUM> that is fixed in the valve hole 36a by a screw mechanism 74a, and when the needle <NUM> is rotated and the needle <NUM> is made to advance toward the inlet 36b side, the cross-sectional area of the flow path of the second hole portion 42b is reduced. In this manner, the first throttle valve <NUM> is capable of variably adjusting a flow rate of the first flow path <NUM>.

As shown in <FIG>, the third throttle valve <NUM> is disposed in a valve hole <NUM> provided midway along the pilot air flow path <NUM>. The valve hole <NUM> is formed from the upper surface 30b side, and the pilot air flow path <NUM> opens on a bottom part and a side part of the valve hole <NUM>. The third throttle valve <NUM> is a check valve equipped throttle valve in which a throttle valve 40a and a check valve 40b are formed integrally, and includes a flow path member <NUM>, a needle <NUM>, and a backflow prevention sealing member <NUM>.

The flow path member <NUM> is a tubular member that seals an upper end of the valve hole <NUM>, and partitions a bottom side of the valve hole <NUM> into an inner side flow path 76a and an outer side flow path 76b. The needle <NUM> is inserted into the flow path member <NUM>, and variably adjusts the cross-sectional area of the inner side flow path 76a. The backflow prevention sealing member <NUM> (check valve 40b) is made from an annular elastic member that is mounted on an outer circumferential portion of the flow path member <NUM>. The backflow prevention sealing member <NUM> is formed with a substantially V-shaped cross section having a concave portion on the upper surface 30b side, and allows the pilot air to pass in a free flowing manner toward the pilot port 48c, while preventing passage of the air in an opposite direction. Accordingly, in the third throttle valve <NUM>, the pilot air that is discharged from the pilot port 48c is throttled by the throttle valve 40a.

The connected relationship of the members constituting the head side flow rate controller <NUM> is shown in <FIG>.

On the other hand, in <FIG>, the rod side flow rate controller 22A, which is connected to the rod side port 18A, is configured in substantially the same manner as the head side flow rate controller <NUM>. In the flow rate controller 22A, the same constituent elements as those of the head side flow rate controller <NUM> are designated by the same reference numerals, and detailed description thereof will be omitted.

Next, a description will be given concerning the configuration of the operation switching valve <NUM> that is connected to the head side flow rate controller <NUM> and the rod side flow rate controller 22A. The operation switching valve <NUM> is a <NUM>-port valve that electrically switches a connection destination of the high pressure air, and includes first through fifth ports 28a to 28e. The first port 28a is connected to the valve side port <NUM> of the head side flow rate controller <NUM>, and the second port 28b is connected to the valve side port <NUM> of the rod side flow rate controller 22A. The third port 28c and the fifth port 28e are connected to the exhaust ports <NUM>, and the fourth port 28d is connected to the high pressure air supply source <NUM>.

At a first position shown in <FIG>, the operation switching valve <NUM> allows the first port 28a and the fourth port 28d to communicate with each other, and allows the second port 28b and the fifth port 28e to communicate with each other. In this manner, the operation switching valve <NUM> supplies the high pressure air from the high pressure air supply source <NUM> to the head side flow rate controller <NUM>, and discharges the exhaust air of the rod side pressure chamber 12b from the exhaust port <NUM>.

Further, at a second position, the operation switching valve <NUM> allows the first port 28a and the third port 28c to communicate with each other, and allows the second port 28b and the fourth port 28d to communicate with each other. In this manner, the operation switching valve <NUM> supplies the high pressure air from the high pressure air supply source <NUM> to the rod side flow rate controller 22A, and discharges the exhaust air of the head side pressure chamber 12a from the exhaust port <NUM>.

The flow rate controllers <NUM> and 22A and the drive device <NUM> of the present embodiment are configured in the manner described above. Next, actions thereof will be described below together with their operations. In this instance, with reference to <FIG> and <FIG>, a description will be given as an example of an operating stroke for moving the piston <NUM> toward the rod side port 18A.

As shown in <FIG>, in the operating stroke, the operation switching valve <NUM> is switched to the first position, and the high pressure air supply source <NUM> is connected to the head side flow rate controller <NUM>. The high pressure air flows into the flow rate controller <NUM> through the valve side port <NUM>, and flows into the first flow path <NUM>, the second flow path <NUM>, and the pilot air flow path <NUM>. As shown by the arrow A, the high pressure air primarily passes through the check valve 38b and the pilot check valve <NUM> of the second flow path <NUM>, and is supplied in a free flowing manner to the head side port <NUM> of the air cylinder <NUM>. Further, the high pressure air which has flowed into the pilot air flow path <NUM> flows as pilot air in a forward direction through the check valve 40b, and is stored in the piston chamber 60a (see <FIG>) of the pilot check valve <NUM>.

On the other hand, the exhaust air discharged from the rod side pressure chamber 12b flows from the cylinder side port <NUM> into the rod side flow rate controller 22A. The pilot air that was stored during the previous stroke remains in the piston chamber 60a of the pilot check valve <NUM> of the flow rate controller 22A, and as shown in <FIG>, the pilot piston <NUM> projects toward the check valve accommodating portion 60c side. Therefore, as shown in <FIG>, the pilot check valve <NUM> allows the exhaust air to pass from the outlet 48b toward the inlet 48a.

Accordingly, the exhaust air flows through the first flow path <NUM> as shown by the arrow B1, and also flows through the second flow path <NUM> as shown by the arrow B2. The exhaust air is throttled by the first throttle valve <NUM> of the first flow path <NUM>, as well as by the second throttle valve <NUM>, and as shown by the arrow B1 + B2, passes through the operation switching valve <NUM> and is discharged from the exhaust port <NUM>. The operating speed of the piston <NUM> of the air cylinder <NUM> is determined by the flow rate of the exhaust air of the rod side flow rate controller 22A.

Further, while the piston <NUM> carries out the operating stroke, the pilot air of the rod side pilot check valve <NUM> is gradually discharged through the pilot air flow path <NUM> and the third throttle valve <NUM>. Along therewith, the pressure of the pilot air of the pilot check valve <NUM> gradually decreases.

When the pressure of the rod side pilot check valve <NUM> falls below a predetermined value, the pilot piston <NUM> is displaced toward the cap <NUM> side by the elastic force of the return spring <NUM>, and the rod portion 66c is pulled inward toward the intermediate portion 60b side as shown in <FIG>. As a result, the valve element <NUM> of the check valve accommodating portion 60c closes the reduced diameter portion 60d, and the pilot check valve <NUM> switches to a state preventing passage of the exhaust air.

In addition, as shown by the arrow B1 in <FIG>, the exhaust air passes only through the first flow path <NUM>. The flow rate of the exhaust air is throttled by the first throttle valve <NUM>, whereby the operating speed of the piston <NUM> decreases. Consequently, shocks in the air cylinder <NUM> when the piston <NUM> reaches the stroke end are mitigated.

In accordance with the foregoing, the stroke operation by the drive device <NUM> of the air cylinder <NUM> comes to an end. Thereafter, by the operation switching valve <NUM> being switched to the second position, the return stroke is carried out. In the return stroke, the exhaust air flows to the head side flow rate controller <NUM>, and the high pressure air flows to the rod side flow rate controller 22A. The operations of the drive device <NUM> 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 22A, and since the operations in the return stroke and the operations in the operating stroke are basically the same, a description of such operations will be omitted.

The flow rate controllers <NUM> and 22A and the drive device <NUM> of the present embodiment realize the following advantageous effects.

The flow rate controller <NUM> or 22A, which is connected between a port of the air cylinder <NUM> and the operation switching valve <NUM> that switches and thereby connects the high pressure air supply source <NUM> or the exhaust port <NUM> to the air cylinder <NUM>, comprises the housing <NUM> including the cylinder side port <NUM> connected to the port of the air cylinder <NUM> and the valve side port <NUM> connected to the operation switching valve <NUM>, the first flow path <NUM> provided inside the housing <NUM>, and connecting the cylinder side port <NUM> and the valve side port <NUM>, the first throttle valve <NUM> disposed in the first flow path <NUM>, the second flow path <NUM> provided inside the housing <NUM> and disposed in parallel with the first flow path <NUM>, the second throttle valve <NUM> disposed in the second flow path <NUM>, the pilot check valve <NUM> disposed in the second flow path <NUM> and connected in series with the second throttle valve <NUM>, the pilot air flow path <NUM> provided inside the housing <NUM>, and connecting the valve side port <NUM> and the pilot port 48c of the pilot check valve <NUM> to supply and discharge the pilot air to and from the pilot check valve <NUM>, and the third throttle valve <NUM> disposed in the pilot air flow path <NUM>, wherein, depending on the pressure of the pilot air, the pilot check valve <NUM> switches between a state allowing passage of the exhaust air discharged from the air cylinder <NUM>, and a state preventing the passage of the exhaust air.

According to the above-described configuration, since the pilot check valve <NUM>, which is of a simple structure, is 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.

In the above-described flow rate controller <NUM> or 22A, there may further be provided the check valve 38b which is disposed in the second throttle valve <NUM>, and allows passage of the air flowing from the valve side port <NUM> toward the cylinder side port <NUM>. By providing the check valve 38b, the high pressure air can be supplied to the air cylinder <NUM> in a free flowing manner through the check valve 38b, and the air cylinder <NUM> becomes capable of being operated at a high speed.

In the above-described flow rate controller <NUM> or 22A, the third throttle valve <NUM> may be equipped with the throttle valve 40a, and the check valve 40b which is disposed in parallel with the throttle valve 40a, and allows passage of the air flowing toward the pilot port 48c. In accordance with such a configuration, with a simple device configuration, it is possible to adjust the timing at which the pilot check valve <NUM> is switched.

In the above-described flow rate controller <NUM> or 22A, the pilot check valve <NUM> includes the through hole <NUM> including the piston chamber 60a communicating with the pilot port 48c, the check valve accommodating portion 60c communicating with the cylinder side port <NUM>, and the intermediate portion 60b connecting the piston chamber 60a and the check valve accommodating portion 60c, and communicating with the second throttle valve <NUM>, the pilot piston <NUM> which is disposed in the piston chamber 60a and the intermediate portion 60b, and projects toward the check valve accommodating portion 60c or retracts away from the check valve accommodating portion 60c toward a side of the intermediate portion 60b, based on the pressure of the pilot air, and the valve element <NUM> disposed in the check valve accommodating portion 60c, and arranged so as to be capable of closing a connecting portion between the intermediate portion 60b and the check valve accommodating portion 60c, wherein, in a state in which the pilot piston <NUM> has retracted toward the side of the intermediate portion 60b, the valve element <NUM> allows passage of the high pressure air in a direction from the valve side port <NUM> to the cylinder side port <NUM>, and prevents passage of the exhaust air in a direction opposite thereto, whereas in a state in which the pilot piston <NUM> projects toward a side of the check valve accommodating portion 60c, the valve element <NUM> allows passage of the high pressure air and the exhaust air.

In accordance with the above-described configuration, since the flow rate controllers <NUM> and 22A that carry out switching of the flow paths can be realized without the need for component parts that require a large number of production steps, such as a spool or the like on which grinding or polishing or surface treatment is carried out, the manufacturing cost of the flow rate controllers <NUM> and 22A can be suppressed.

In the above-described flow rate controller <NUM> or 22A, in the pilot check valve <NUM>, when the pressure of the pilot air becomes greater than or equal to a predetermined value, the pilot piston <NUM> may project toward the side of the check valve accommodating portion 60c to allow the passage of the high pressure air and the exhaust air. In accordance with such a configuration, the high pressure air can be supplied to the air cylinder <NUM> in a free flowing manner through the second flow path <NUM>, and the air cylinder <NUM> can be operated at a high speed.

Claim 1:
A flow rate controller (<NUM>, 22A) connectable between a port of an air cylinder (<NUM>), and an operation switching valve (<NUM>) configured to switch and thereby connect a high pressure air supply source (<NUM>) or an exhaust port (<NUM>) to the air cylinder, the flow rate controller comprising:
a housing (<NUM>) including a cylinder side port (<NUM>) connectable to the port of the air cylinder, and a valve side port (<NUM>) connectable to the operation switching valve;
a first flow path (<NUM>) provided inside the housing, and configured to connect the cylinder side port and the valve side port;
a first throttle valve (<NUM>) disposed in the first flow path;
a second flow path (<NUM>) provided inside the housing and disposed in parallel with the first flow path;
a second throttle valve assembly (<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 throttle valve assembly;
a pilot air flow path (<NUM>) provided inside the housing, and configured to connect the valve side port and a pilot port (48c) of the pilot check valve to supply and discharge pilot air to and from the pilot check valve; and
a third throttle valve assembly (<NUM>) disposed in the pilot air flow path,
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 air cylinder, and a state preventing the passage of the exhaust air.