Patent Description:
Conventionally, various valves (time delay valves) for performing a delay operation have been proposed. Such a time delay valve is used, for example, for two-stage speed control in which a fluid pressure cylinder operated by fluid pressure is switched from a first speed (high speed) to a second speed (low speed). Such two-stage speed control is effective in reducing the impact at the stroke end of the fluid pressure cylinder, shortening the cycle time by increasing the operation speed, and the like.

Various time delay valves have been proposed which utilize the supply pressure of a pilot fluid to operate the valve. In this case, a throttle and a volume portion are used in the delay mechanism, and the switching operation of the valve is performed at the timing when a predetermined amount of pilot fluid is supplied to the volume portion (for example, <CIT>, <CIT>, <CIT>, and <CIT>). It is also known to use the above delay mechanism in a two-speed switching flow rate controller (for example, <CIT> and <CIT>).

<CIT> and <CIT> disclose known configurations of fluid control valves.

However, the conventional time delay valve has a problem that when the supply pressure of the pilot fluid fluctuates, the flow rate of the pilot fluid passing through the throttle of the delay mechanism fluctuates and the timing at which the valve is switched varies.

Therefore, when the time delay valve is used in a place where the pressure tends to fluctuate, such as a pressure line in a factory, the switching timing of the time delay valve varies. As a result, since the operation time of each of the devices using the time delay valve varies, it is necessary to provide a predetermined waiting time in consideration of the variation in the operation of devices, which causes a problem that the cycle time is prolonged.

Therefore, it is an object of the present invention to provide a time delay valve and a flow rate controller capable of suppressing the influence on the switching timing due to the fluctuation of the supply pressure of the pilot fluid.

This problem is solved by the time delay valve according to claim <NUM> and the flow rate controller according to claim <NUM>. Preferred embodiments of the invention are evident from the dependent claims.

According to the time delay valve and the flow rate controller of the above-described aspects, it is possible to suppress the influence on the switching timing due to the fluctuation of the supply pressure of the pilot fluid.

A preferred embodiment of a time delay valve and a flow rate controller according to the present invention will be described in detail below with reference to the accompanying drawings.

A time delay valve <NUM> of the present embodiment shown in <FIG> and <FIG> is mounted on a cylinder or a drive circuit of various fluid pressure devices, and is used for a pneumatic device or the like in a production line of a factory. The time delay valve <NUM> is used to control a flow rate of a control target fluid such as air. The control target fluid and the pilot fluid are not limited to air.

As shown in <FIG>, the time delay valve <NUM> of the present embodiment includes, inside a main body <NUM>, a first flow path <NUM>, a second flow path <NUM>, a switching valve <NUM>, a biasing member <NUM>, a drive mechanism <NUM>, a delay mechanism <NUM>, a compensation mechanism <NUM>, and a return mechanism <NUM>. Among them, the first flow path <NUM> and the second flow path <NUM> are flow paths through which the control target fluid flows, and are flow paths that connect a first connection port <NUM> and a second connection port <NUM> of the main body <NUM>.

The first flow path <NUM> and the second flow path <NUM> are flow paths provided in parallel, and a path through which the control target fluid flows is selectively switched between these flow paths, by a switching operation of the switching valve <NUM>. The second flow path <NUM> is provided with a first throttle valve <NUM> for throttling a flow rate so as to pass the control target fluid under a condition different from that of the first flow path <NUM>. The first throttle valve <NUM> may be provided in the first flow path <NUM> instead of the second flow path <NUM>. Alternatively, the first throttle valve <NUM> may be provided in both the first flow path <NUM> and the second flow path <NUM>. Further, the first throttle valve <NUM> is not limited to a variable throttle valve having a variable flow rate, but may be a fixed throttle valve that allows a fluid to pass therethrough at a constant flow rate.

The switching valve <NUM> is configured as a three-port valve that can be switched between a first position and a second position. At the first position, the switching valve <NUM> causes the first connection port <NUM> and the second connection port <NUM> to communicate with each other via the first flow path <NUM>. At the second position, the switching valve <NUM> causes the first connection port <NUM> and the second connection port <NUM> to communicate with each other via the second flow path <NUM>. The switching valve <NUM> is configured to be switched between the first position and the second position by the biasing force of the biasing member <NUM>, the drive mechanism <NUM>, the compensation mechanism <NUM>, and the return mechanism <NUM>.

The biasing member <NUM> is a member that biases the switching valve <NUM> toward the first position, and is configured by, for example, an elastic member such as a spring or rubber. In a state in which pilot fluid is not supplied to the switching valve <NUM>, the switching valve <NUM> is held at the first position by the biasing force of the biasing member <NUM>. The biasing member <NUM> has such an elastic force that the switching valve <NUM> is not switched to the second position by its own weight.

The drive mechanism <NUM> is a member that generates a biasing force that biases the switching valve <NUM> toward the second position under the action of the pilot fluid. The drive mechanism <NUM> includes a piston mechanism disposed on an opposite side from the biasing member <NUM> as will be described later, and generates a biasing force corresponding to the supply pressure of the pilot fluid. The drive mechanism <NUM> switches the switching valve <NUM> to the second position at a timing at which its biasing force exceeds the biasing forces of the biasing member <NUM> and the compensation mechanism <NUM>.

A pilot fluid is supplied to the drive mechanism <NUM> via a pilot flow path <NUM>. The pilot flow path <NUM> is a flow path that connects a pilot port <NUM> of the main body <NUM> and the drive mechanism <NUM>, and guides the pilot fluid flowing in from the pilot port <NUM> to the drive mechanism <NUM>.

The delay mechanism <NUM> includes a delay throttle valve <NUM> provided in the pilot flow path <NUM>, a volume portion <NUM> provided downstream of the delay throttle valve <NUM>, and the compensation mechanism <NUM>. The delay throttle valve <NUM> is provided with a throttle valve 40a by which flow rate can be varied and a check valve 40b, in parallel. The delay throttle valve <NUM> can adjust the increase speed of the pressure of the pilot fluid acting on the drive mechanism <NUM> by throttling the flow rate of the pilot fluid flowing into the volume portion <NUM> via the pilot flow path <NUM>, and can thus adjust the switching timing of the switching valve <NUM>. The volume portion <NUM> is configured as a volume of the pilot flow path <NUM> on the downstream side of the delay throttle valve <NUM> and as a volume of the piston mechanism of the drive mechanism <NUM>. If necessary, a member such as a storage tank may be added.

The compensation mechanism <NUM> is a member that generates a biasing force biasing the switching valve <NUM> toward the first position. The compensation mechanism <NUM> is connected to the pilot port <NUM> via a compensation flow path <NUM> that branches off from the pilot flow path <NUM> on the upstream side of the delay throttle valve <NUM>. The compensation mechanism <NUM> is supplied with the pilot fluid through the compensation flow path <NUM>. The compensation mechanism <NUM> generates a biasing force toward the first position having a magnitude corresponding to the supply pressure of the pilot fluid. That is, when the supply pressure of the pilot fluid increases, the biasing force of the compensation mechanism <NUM> increases. When the supply pressure of the pilot fluid decreases, the biasing force of the compensation mechanism <NUM> decreases. However, the biasing force of the compensation mechanism <NUM> rises more quickly than the biasing force of the drive mechanism <NUM>. The biasing force that defines the timing at which the switching valve <NUM> is switched is increased or decreased in accordance with the supply pressure of the pilot fluid.

The return mechanism <NUM> is a member that generates a biasing force that biases the switching valve <NUM> toward the first position. The return mechanism <NUM> is connected to the first flow path <NUM> via a return flow path <NUM>. The return mechanism <NUM> generates a biasing force having a magnitude corresponding to the supply pressure of the control target fluid in the first flow path <NUM>. The supply pressure of the pilot fluid increases or decreases as to the amount of the pilot fluid in the volume portion <NUM>. The return mechanism <NUM> stabilizes the return timing at which the switching valve <NUM> is switched from the second position to the first position by causing the biasing force corresponding to the supply pressure of the pilot fluid (control target fluid) to act on the switching valve <NUM>.

Next, a specific structure of the time delay valve <NUM> will be described with reference to <FIG>.

As shown in <FIG>, the main body <NUM> of the time delay valve <NUM> is formed in a rectangular frame shape in which a front part 12a, a back part 12b, a top part 12c, and a bottom part 12d are integrated, and both side portions thereof are opening portions 12e1 and 12e2. On both side portions of the main body <NUM>, a plurality of bosses <NUM> for attaching side plates <NUM> are provided at predetermined positions of the front part 12a, the back part 12b, the top part 12c, and the bottom part 12d of the main body <NUM>. Another time delay valve <NUM> may be connected through the opening portions 12e1 and 12e2. In the present embodiment, since a single time delay valve <NUM> is used, a pair of side plates <NUM> are attached so as to cover the opening portions 12e1 and 12e2 on the side portions.

The first connection port <NUM>, a flow rate adjustment knob 34a of the first throttle valve <NUM>, and an adjustment knob 40c of the delay throttle valve <NUM> are disposed on the front part 12a of the main body <NUM>. In addition, the second connection port <NUM> is provided on the back part 12b. A substantially cylindrical valve housing portion <NUM> is provided between the top part 12c and the bottom part 12d of the main body <NUM>. The switching valve <NUM> is housed in the valve housing portion <NUM>.

The first flow path <NUM> extends from the first connection port <NUM> on the front part 12a toward the valve housing portion <NUM>. Connection ports <NUM> extend laterally from side portions of the first flow path <NUM>. Each of the connection ports <NUM> is formed in a cylindrical shape and extends to a side portion on an opening portion 12e1 side and a side portion on an opening portion 12e2 side. A sealing wall 56a is provided in each of the side portion of the connection port <NUM> on the opening portion 12e1 side and an inner portion thereof on the opening portion 12e2 side. When a hole is drilled in the sealing wall 56a as necessary and a plurality of time delay valves <NUM> are connected to each other, the hole is used as a connection opening for supplying a pilot fluid or a control target fluid to an adjacent time delay valve <NUM>. When only a single time delay valve <NUM> is used as in the present embodiment, drilling through the sealing wall 56a on the opening portion 12e1 side and drilling through the sealing wall 56a on the opening portion 12e2 side of the connection ports <NUM> are not performed, and the connection ports <NUM> are sealed by the sealing walls 56a.

The first throttle valve <NUM> is connected to the valve housing portion <NUM> at a position closer to the top part 12c than the first flow path <NUM> is. For the first throttle valve <NUM>, the flow rate adjustment knob 34a is provided on the front part 12a, and the flow rate of the second flow path <NUM> can be adjusted by the flow rate adjustment knob 34a.

The delay throttle valve <NUM> is connected to the valve housing portion <NUM> at a position closer to the top part 12c than the first throttle valve <NUM> is. The pilot flow paths <NUM> are connected to side portions of the delay throttle valve <NUM>. The pilot flow paths <NUM> are connected to the valve housing portion <NUM> via the delay throttle valve <NUM>. The pilot flow paths <NUM> extend in a cylindrical shape toward the opening portion 12e1 side and the opening portion 12e2 side, and a sealing wall 36a is formed on each of the opening portion 12e1 side and the opening portion 12e2 side. Among these sealing walls 36a, a hole is drilled in the sealing wall 36a on the opening portion 12e2 side, and the pilot port <NUM> is connected to the pilot flow path <NUM> on the opening portion 12e2 side. When the side plate <NUM> is assembled, the pilot port <NUM> protrudes to the outside of the side plate <NUM>, and a tube member can be connected to the pilot port <NUM>. The pilot fluid is supplied to the pilot port <NUM> at predetermined timing.

As shown in <FIG>, the switching valve <NUM> is configured as a spool valve in which a spool <NUM> is housed inside the valve housing portion <NUM>. The valve housing portion <NUM> has therein a through hole <NUM> penetrating from the top part 12c to a bottom part 12d side of the main body <NUM>. Both ends of the through hole <NUM> are sealed with end caps <NUM>, <NUM>. The spool <NUM> and a sleeve <NUM> housing the spool <NUM> are accommodated in the through hole <NUM> between the end caps <NUM> and <NUM>.

The end cap <NUM> is fitted into an end portion of the through hole <NUM> on a top part 12c side. A storage chamber 64a for storing the pilot fluid is formed inside the end cap <NUM>. The storage chamber 64a communicates with the delay throttle valve <NUM> through a hole portion 64b and constitutes a part of the volume portion <NUM> for storing the pilot fluid.

The sleeve <NUM> is fitted into the through hole <NUM> between the end caps <NUM>, <NUM>. In the sleeve <NUM>, a sliding hole 62a is formed penetrating from the top part 12c side to the bottom part 12d side. The spool <NUM> is slidably disposed in the sliding hole 62a.

A drive piston chamber <NUM> is formed in the end portion of the sleeve <NUM> on the top part 12c side. The drive piston chamber <NUM> is a portion for housing a drive piston <NUM> formed at one end of the spool <NUM>. The drive piston chamber <NUM> is partitioned by the drive piston <NUM> into a first empty chamber 72a on the top part 12c side and a second empty chamber 72b on the bottom part 12d side. The first empty chamber 72a of the drive piston chamber <NUM> communicates with the storage chamber 64a of the end cap <NUM>. An opening portion 44a of the compensation flow path <NUM> is formed in the second empty chamber 72b of the drive piston chamber <NUM>, and the second empty chamber 72b communicates with the compensation flow path <NUM>.

The sleeve <NUM> is formed with a first cutout hole <NUM> communicating with the first throttle valve <NUM>, a second cutout hole <NUM> communicating with the second connection port <NUM>, and a third cutout hole <NUM> communicating with the first flow path <NUM>. The first cutout hole <NUM>, the second cutout hole <NUM>, and the third cutout hole <NUM> are formed to penetrate through the sleeve <NUM> in a thickness direction.

A return piston chamber <NUM> for slidably housing a return piston <NUM> is formed at an end portion of the sleeve <NUM> on the bottom part 12d side. The return piston chamber <NUM> is sealed by the end cap <NUM> fitted into the through hole <NUM> from the bottom part 12d side. The return piston chamber <NUM> is partitioned by the return piston <NUM> into an empty chamber on the end cap <NUM> side and an empty chamber on the top part 12c side. An empty chamber of the return piston chamber <NUM> on the end cap <NUM> side communicates with the first flow path <NUM> via a fourth cutout hole <NUM> constituting the return flow path <NUM>. An empty chamber of the return piston chamber <NUM> on the top part 12c side communicates with the first flow path <NUM>.

The return piston <NUM> is formed at an end portion of the spool <NUM> on the bottom part 12d side, and an end surface of the return piston <NUM> serves as a fourth pressure receiving surface 80a. The fourth pressure receiving surface 80a receives the supply pressure of the control target fluid flowing into the return piston chamber <NUM> through the return flow path <NUM>, and generates a biasing force that urges the spool <NUM> toward the first position.

The biasing member <NUM> is housed in an empty chamber between the return piston <NUM> and the end cap <NUM> in the return piston chamber <NUM>. The biasing member <NUM> is, for example, a spring in the shape of a coil, and is in contact with the fourth pressure receiving surface 80a of the return piston <NUM>. The biasing member <NUM> urges the fourth pressure receiving surface 80a (spool <NUM>) toward the first position on the top part 12c side by its elastic force. The elastic force (biasing force) of the biasing member <NUM> is set to a value greater than the weight of the spool <NUM>, and prevents the spool <NUM> from moving toward the bottom part 12d side (second position side) when not in use, i.e., when neither the pilot fluid nor the control target fluid is supplied.

As shown in <FIG>, the drive piston <NUM> is formed at one end of the spool <NUM> on the first position side (top part 12c side). An end surface of the drive piston <NUM> serves as a first pressure receiving surface 70a, and generates a biasing force that biases the spool <NUM> toward the second position upon receiving a supply force of the pilot fluid.

A sliding portion <NUM> having a diameter smaller than that of the drive piston <NUM> is formed on the second position side of the drive piston <NUM>. Further, a second pressure receiving surface 70b is formed at a stepped portion between the sliding portion <NUM> and the drive piston <NUM>. The second pressure receiving surface 70b is formed on an opposite side from the first pressure receiving surface 70a, and generates a biasing force that biases the spool <NUM> toward the first position by receiving the supply force of the pilot fluid. The second pressure receiving surface 70b constitutes a part of the compensation mechanism <NUM>. Since the area of the second pressure receiving surface 70b is smaller than the area of the first pressure receiving surface 70a, when the internal pressure of the storage chamber 64a sufficiently increases, the biasing force of the first pressure receiving surface 70a exceeds the biasing forces of the second pressure receiving surface 70b and the biasing member <NUM>.

The sliding portion <NUM> extends toward the second position side (bottom part 12d side). The sliding portion <NUM> is formed with a first recessed portion <NUM>, a first partition wall <NUM>, a second recessed portion <NUM>, a second partition wall <NUM>, a third recessed portion <NUM>, and the return piston <NUM> in this order from the first position side. A plurality of packing housing grooves <NUM> are formed in predetermined portions of the spool <NUM>. As shown in <FIG>, an O-ring <NUM> is mounted in each of the packing housing grooves <NUM> to seal a gap between the spool <NUM> and the sleeve <NUM>.

As shown in <FIG>, when the spool <NUM> is in the first position, the first recessed portion <NUM> communicates with the first cutout hole <NUM>, the second recessed portion <NUM> communicates with the second cutout hole <NUM>, and the third recessed portion <NUM> communicates with the third cutout hole <NUM>. Further, the first partition wall <NUM> air-tightly (liquid-tightly) partitions the first cutout hole <NUM> and the second cutout hole <NUM>. At this time, the second partition wall <NUM> is disposed at the position of the second cutout hole <NUM>, and the second cutout hole <NUM> and the third cutout hole <NUM> communicate with each other through the third recessed portion <NUM>. The first connection port <NUM> and the second connection port <NUM> are connected to each other through the first flow path <NUM>.

On the other hand, when the spool <NUM> is at the second position on the bottom part 12d side, the first partition wall <NUM> is disposed at the position of the second cutout hole <NUM>, and the first cutout hole <NUM> and the second cutout hole <NUM> communicate with each other through the first recessed portion <NUM>. At this time, the second partition wall <NUM> comes into close contact with an inner peripheral surface of the sleeve <NUM> between the second cutout hole <NUM> and the third cutout hole <NUM>, and communication between the second cutout hole <NUM> and the third cutout hole <NUM> is blocked. When the spool <NUM> is in the second position, the first connection port <NUM> and the second connection port <NUM> are connected through the second flow path <NUM> and the first throttle valve <NUM>.

The time delay valve <NUM> according to the present embodiment is configured as described above, and the operation thereof will be described below.

As shown in <FIG>, the time delay valve <NUM> is connected to an operation switching valve <NUM> and is used as a driving device for a fluid pressure device such as an air cylinder. The illustrated fluid circuit is a fluid circuit in which the flow rate of the control target fluid discharged from a fluid discharge unit <NUM> is throttled after a predetermined delay time using the time delay valve <NUM>.

The operation switching valve <NUM> is a five-port valve and has ports <NUM> to <NUM>. The pilot port <NUM> is connected to the first port <NUM>, and the first connection port <NUM> is connected to the second port <NUM>. The fluid discharge unit <NUM> is connected to the third port <NUM> and the fifth port <NUM>, and a fluid supply source <NUM> is connected to the fourth port <NUM>. The fluid supply source <NUM> is, for example, a pressure line, an air compressor or the like in a factory.

The operation switching valve <NUM> is switched between a first position and a second position. In the first position of the operation switching valve <NUM>, the first port <NUM> and the fourth port <NUM> are connected to each other, and the second port <NUM> and the fifth port <NUM> are connected to each other. That is, the fluid supply source <NUM> is connected to the pilot port <NUM> to supply the pilot fluid, and the fluid discharge unit <NUM> is connected to the first connection port <NUM>. Then, the pilot fluid is supplied to the pilot flow path <NUM> through the pilot port <NUM>.

In the time delay valve <NUM> in the initial state, the switching valve <NUM> is disposed at the first position by the biasing force of the biasing member <NUM>, and the first connection port <NUM> and the second connection port <NUM> communicate with each other through the first flow path <NUM>. A part of the pilot fluid flows into the compensation mechanism <NUM> through the compensation flow path <NUM> branched from the pilot flow path <NUM>. Another part of the pilot fluid flows into the volume portion <NUM> (storage chamber 64a) at a predetermined flow rate through the delay throttle valve <NUM> to gradually increase the pressure of the pilot fluid acting on the drive mechanism <NUM>.

As shown in <FIG>, a biasing force <NUM> due to a pressure acting on the second pressure receiving surface 70b (compensation mechanism <NUM>) of the drive piston <NUM>, a biasing force <NUM> due to a pressure acting on the first pressure receiving surface 70a (drive mechanism <NUM>), and a biasing force <NUM> due to the biasing member <NUM>, act on the spool <NUM>. The spool <NUM> (the switching valve <NUM>) is switched to the second position at timing when the biasing force <NUM> in the second position direction becomes larger than a combined force of the biasing force <NUM> in the first position direction and the biasing force <NUM>.

When the switching valve <NUM> is switched to the second position, the first connection port <NUM> and the second connection port <NUM> shown in <FIG> are connected to each other through the second flow path <NUM>, and the flow rate of the control target fluid is regulated by the first throttle valve <NUM>. As described above, the time delay valve <NUM> operates such that the switching valve <NUM> is switched after a predetermined delay time elapses from the supply of the pilot fluid.

Here, when the pressure of the fluid supply source <NUM> increases, the flow rate of the pilot fluid passing through the delay throttle valve <NUM> of the pilot flow path <NUM> increases, the rising speed of the charge pressure of the volume portion <NUM> becomes fast, and the increase of the biasing force <NUM> becomes fast. Conversely, when the pressure when the pressure of the fluid supply source <NUM> decreases, the flow rate of the pilot fluid passing through the delay throttle valve <NUM> decreases, and the increase of the biasing force <NUM> is delayed. Therefore, there is a concern that the timing of the switching operation of the switching valve <NUM> varies due to the fluctuation of the pressure of the fluid supply source <NUM>.

Therefore, in the time delay valve <NUM> according to the present embodiment, the biasing force <NUM> is generated by applying the supply pressure of the pilot fluid to the second pressure receiving surface 70b, prior to the increase of the biasing force <NUM>. Since the magnitude of the biasing force <NUM> is proportional to the pressure of the pilot fluid, the biasing force <NUM> acts to compensate the increasing speed of the biasing force <NUM>. That is, as the pressure of the fluid supply source <NUM> increases, the biasing force <NUM> increases accordingly. Then, the magnitude of the biasing force <NUM> required for switching the spool <NUM> increases, and the influence of the increase in the increasing speed of the urging force <NUM> is cancelled, so that it is possible to suppress the variation of the switching timing (delay time) of the spool <NUM>.

In addition, when the pressure from the fluid supply source <NUM> decreases, the supply pressure of the pilot fluid acting on the second pressure receiving surface 70b also decreases. As a result, the biasing force <NUM> decreases, and the spool <NUM> can be switched with a smaller biasing force <NUM>. As a result, the influence due to the decrease in the increase rate of the biasing force <NUM> is canceled out, and the variation in the switching timing (delay time) of the spool <NUM> can be suppressed.

In addition, the time delay valve <NUM> of the present embodiment can stabilize the timing of the switching operation of the spool <NUM> even in the return operation. When the operation switching valve <NUM> shown in <FIG> is switched to the second position, the first port <NUM> and the third port <NUM> are connected, and the second port <NUM> and the fourth port <NUM> are connected. That is, the fluid supply source <NUM> is connected to the first connection port <NUM> of the time delay valve <NUM>, and the fluid discharge unit <NUM> is connected to the pilot port <NUM>.

The pilot fluid stored in the volume portion <NUM> is discharged from the fluid discharge unit <NUM> via the check valve 40b and the pilot flow path <NUM>. Then, the spool <NUM> (the switching valve <NUM>) returns to the first position at timing when the pressure of the pilot fluid acting on the drive mechanism <NUM> falls below the predetermined value and the biasing force <NUM> in <FIG> falls below the biasing force <NUM> of the biasing member <NUM>. However, since the amount of the pilot fluid stored in the volume portion <NUM> increases or decreases in accordance with the pressure fluctuation of the fluid supply source <NUM> which is the supply pressure of the pilot fluid, the timing at which the spool <NUM> (the switching valve <NUM>) returns to the first position is affected by the pressure of the fluid supply source <NUM>.

In the present embodiment, a part of the control target fluid in the first connection port <NUM> is supplied to the return piston chamber <NUM> of the return mechanism <NUM> through the return flow path <NUM> communicating with the first connection port <NUM>. The return piston <NUM> of the return mechanism <NUM> generates a biasing force toward the second position with a magnitude corresponding to the supply pressure of the control target fluid (the pressure of the fluid supply source <NUM>). Since the biasing force of the return mechanism <NUM> is superimposed on the biasing force of the biasing member <NUM>, the biasing force of the return mechanism <NUM> acts so as to cancel the change in the amount of the pilot fluid stored in the volume portion <NUM>. As a result, the time delay valve <NUM> can suppress variation in the timing of the return operation due to the fluctuation in the pressure of the fluid supply source <NUM>.

<FIG> is a diagram illustrating a transition of the charge pressure of the pilot air in the volume portion <NUM> of the time delay valve according to Comparative Example and a state of variation of the switching timing (delay time). In the time delay valve of Comparative Example, the compensation flow path <NUM> of <FIG> is opened to the atmosphere so that the biasing force <NUM> corresponding to the pressure of the pilot fluid is not generated.

Here, an example is shown in which the supply pressure of the pilot fluid from the fluid supply source <NUM> are varied by ±<NUM> MPa with respect to a reference pressure of <NUM> MPa. As the pressure of the fluid supply source <NUM> increases, the charge pressure of the volume portion <NUM> increases more rapidly. Also, as the pressure of the fluid supply source <NUM> decreases, the increase in the charge pressure of the volume portion <NUM> slows. In the case where only the biasing force <NUM> of the biasing member <NUM> acts on the spool <NUM>, the spool <NUM> is switched when the constant charge pressure <NUM> MPa is reached, but the timing (delay time) of the switching operation greatly varies due to the variation in the increasing speed of the charge pressure.

On the other hand, as shown in <FIG>, in the time delay valve <NUM> of the present embodiment, since the charge pressure of the volume portion <NUM> when the spool <NUM> is switched is increased or decreased by the compensation mechanism <NUM>, the variation width of the delay time can be suppressed.

The time delay valve <NUM> of the present embodiment has the following effects.

The time delay valve <NUM> according to the present embodiment includes the switching valve <NUM> configured to be switched between the first position and the second position; the biasing member <NUM> configured to bias the switching valve <NUM> toward the first position; the drive mechanism <NUM> configured to bias the switching valve <NUM> toward the second position under the action of the supply pressure of the pilot fluid; the pilot flow path <NUM> configured to guide the pilot fluid to the drive mechanism <NUM>; and the delay mechanism <NUM> configured to delay switching timing of the switching valve <NUM>, wherein the delay mechanism <NUM> includes: the delay throttle valve <NUM> provided in the pilot flow path <NUM>; and the compensation mechanism <NUM> configured to bias the switching valve <NUM> toward the first position under the action of the supply pressure of the pilot fluid.

According to the configuration described above, the biasing force <NUM> (see <FIG>) corresponding to the pressure of the pilot fluid can be applied to the switching valve <NUM> by the compensation mechanism <NUM>. Thus, in accordance with the fluctuation, the supply pressure of the pilot fluid can change the biasing force <NUM> of the drive mechanism <NUM> when the switching valve <NUM> is switched from the first position to the second position, and the variation width of the delay time due to the fluctuation in the supply pressure of the pilot fluid can be suppressed.

In the time delay valve <NUM>, the compensation mechanism <NUM> includes a piston mechanism configured to generate a biasing force opposite to that of the drive mechanism <NUM> under the action of the supply pressure of the pilot fluid. In accordance with this configuration, it is possible to generate the biasing force <NUM> corresponding to the supply pressure of the pilot fluid.

In the time delay valve <NUM> described above, the compensation mechanism <NUM> is supplied with the pilot fluid through the compensation flow path <NUM> branched from the pilot flow path <NUM> on the upstream side of the delay throttle valve <NUM>. With this configuration, the supply pressure of the pilot fluid can be quickly applied to the compensation mechanism <NUM>, and the switching timing of the switching valve <NUM> can be stabilized.

The time delay valve <NUM> described above further includes the first flow path <NUM> configured to allow communication at the first position of the switching valve <NUM>, the second flow path <NUM> configured to allow communication at the second position of the switching valve <NUM>, and the first throttle valve <NUM> provided in at least one of the first flow path <NUM> or the second flow path <NUM>. According to this configuration, the flow rate of the control target fluid can be switched.

The time delay valve <NUM> described above further includes the return mechanism <NUM> configured to generate a biasing force opposite to that of the drive mechanism <NUM>, and the return flow path <NUM> branched from the first flow path <NUM> or the second flow path <NUM> and connected to the return mechanism <NUM>. According to this configuration, even when the supply pressure of the pilot fluid fluctuates, the timing of the return operation of the switching valve <NUM> can be stabilized.

In the time delay valve <NUM> described above, the switching valve <NUM> includes the spool <NUM> and the sleeve <NUM> in which the spool <NUM> slides, the drive mechanism <NUM> includes the drive piston chamber <NUM> provided at one end of the spool <NUM> and the drive piston <NUM> configured to partition the drive piston chamber <NUM> into the first empty chamber 72a on the first position side and the second empty chamber 72b on the second position side, and the drive piston <NUM> includes the first pressure receiving surface 70a on a side of the first empty chamber 72a, the first pressure receiving surface 70a being configured to receive the supply pressure of the pilot fluid to generate the biasing force on the second position side. By integrating the spool <NUM> and the drive piston <NUM> in this way, the device configuration is simplified.

In the above-described time delay valve <NUM>, the drive piston <NUM> is formed integrally with the spool <NUM>, and the compensation mechanism <NUM> includes in the drive piston <NUM> the second pressure receiving surface 70b that faces the second empty chamber 72b and is provided on an opposite side from the first pressure receiving surface 70a. According to this configuration, since the compensation mechanism <NUM> is provided in the drive piston <NUM>, the device configuration is simplified.

In the time delay valve <NUM> described above, the area of the second pressure receiving surface 70b is smaller than the area of the first pressure receiving surface 70a. Thus, the pilot fluid can generate a biasing force for switching the switching valve <NUM> from the first position to the second position.

In the above-described time delay valve <NUM>, the return mechanism <NUM> may include the return piston <NUM> formed at the other end of the spool <NUM> and the return piston chamber <NUM> configured to house the return piston <NUM>. According to this configuration, the return piston <NUM> of the return mechanism <NUM> is integrated with the spool <NUM>, and the device configuration is simplified.

In the time delay valve <NUM> described above, the biasing member <NUM> may be disposed in the return piston chamber <NUM>. According to this configuration, the time delay valve <NUM> can be miniaturized.

As shown in <FIG>, a time delay valve <NUM> according to the present modification does not have the second flow path <NUM> inside a main body 12A, and the second flow path <NUM> and the first throttle valve <NUM> are externally provided. In the configuration of the time delay valve <NUM> in <FIG>, the same components as those of the time delay valve <NUM> described with reference to <FIG> are designated by the same reference numerals, and detailed description of such features will be omitted.

As shown in <FIG>, the time delay valve <NUM> has the first flow path <NUM> that connects the first connection port <NUM> and the second connection port <NUM> of the main body 12A, and a switching valve 18A is provided in the first flow path <NUM>. The switching valve 18A is switchable between a first position and a second position. In the first position, the switching valve 18A allows the fluid in the first flow path <NUM> to flow therethrough, and prevents the fluid in the first flow path <NUM> from allowing therethrough, in the second position.

Similarly to the switching valve <NUM> according to the first embodiment, the switching valve 18A is biased to the first position by the biasing member <NUM>. When the supply of the pilot fluid to the drive mechanism <NUM>, the delay mechanism <NUM>, and the compensation mechanism <NUM> is started, the switching valve 18A is switched to the second position after a predetermined delay period (delay time) has elapsed, and the passage of the control target fluid through the first flow path <NUM> is blocked.

When the second flow path <NUM> having the first throttle valve <NUM> is connected to the time delay valve <NUM> in parallel, as an external member, the flow rate of the control target fluid can be throttled after the lapse of a predetermined delay time, and the same function as that of the time delay valve <NUM> can be obtained.

Similarly to the time delay valve <NUM> according to the first embodiment, the time delay valve <NUM> of the present modification can suppress variation of the switching timing (delay time) due to fluctuation of the supply pressure of the pilot fluid.

The switching valve 18A of the time delay valve <NUM> is not limited to a two-port valve, but may be a five-port valve or the like. The device provided in the second flow path <NUM> is not limited to the first throttle valve <NUM>, and various devices may be connected in place of the first throttle valve <NUM>.

In the present embodiment, a flow rate controller <NUM> using the time delay valve <NUM> according to the first embodiment will be described. As shown in <FIG>, the flow rate controller <NUM> constitutes a fluid circuit for driving a fluid pressure cylinder <NUM>. The flow rate controller <NUM> includes a first module 10A and a second module 10B, both of which have the same structure as that of the time delay valve <NUM> of <FIG>. In the configurations of the first module 10A and the second module 10B, the same components as those of the time delay valve <NUM> of <FIG> are designated by the same reference numerals, and detailed description of such features will be omitted.

As shown in <FIG>, the fluid pressure cylinder <NUM> is a double acting type cylinder, and a piston 120a is provided inside a cylinder chamber <NUM>. The piston 120a divides the cylinder chamber <NUM> of the fluid pressure cylinder <NUM> into a head-side empty chamber 121a and a rod-side empty chamber 121b. Fluid is supplied to and discharged from the head-side empty chamber 121a through a head-side port <NUM>, and fluid is supplied to and discharged from the rod-side empty chamber 121b through a rod-side port <NUM>. The piston 120a is displaced in the axial direction while sliding on the inner wall of the cylinder chamber <NUM> by the fluid (control target fluid) supplied to and discharged from the head-side port <NUM> and the rod-side port <NUM>. A piston rod 120b is connected to the piston 120a, and the piston rod 120b is displaced integrally with the piston 120a.

The flow rate controller <NUM> has a function of performing two-stage speed control for switching the speed of the piston 120a (and the piston rod 120b) of the fluid pressure cylinder <NUM> from a first speed which is a higher speed to a second speed which is a lower speed. The flow rate controller <NUM> can be suitably used when it is required to reduce the impact at the stroke end of the fluid pressure cylinder <NUM> and to shorten the cycle time by realizing a high-speed operation. Hereinafter, the specific structure of the flow rate controller <NUM> will be described.

The flow rate controller <NUM> includes a first supply and discharge path <NUM> connected to the head-side port <NUM>, a second supply and discharge path <NUM> connected to the rod-side port <NUM>, the operation switching valve <NUM> that switches and connects the fluid supply source <NUM> and the fluid discharge unit <NUM> to the first supply and discharge path <NUM> and the second supply and discharge path <NUM>, speed adjusting units <NUM> and <NUM> that regulate the first operation speed of the fluid pressure cylinder <NUM>, and the first module 10A and the second module 10B that regulate the second operation speed.

The first speed and the second module 10B are connected to the first supply and discharge path <NUM>. The first speed adjusting unit <NUM> is a member that regulates an operation speed at the high first speed in a return stroke in which the piston rod 120b of the fluid pressure cylinder <NUM> is pulled in. The first speed includes a check valve 126a and a throttle valve 126b. The check valve 126a is connected in parallel with the throttle valve 126b in such a direction as to allow the fluid supplied to the fluid pressure cylinder <NUM> to pass therethrough without resistance. When the piston 120a of the fluid pressure cylinder <NUM> moves to the head side, the first speed adjusting unit <NUM> regulates the operation speed of the fluid pressure cylinder <NUM> by throttling the flow rate of the fluid discharged from the head-side port <NUM> by the throttle valve 126b. That is, the first speed adjusting unit <NUM> constitutes a meter-out speed controller that regulates the operation speed by the fluid discharged from the fluid pressure cylinder <NUM>.

The second module 10B is connected between the first speed adjusting unit <NUM> and the operation switching valve <NUM> in the first supply and discharge path <NUM>. In the second module 10B, the second connection port <NUM> is connected to the first speed adjusting unit <NUM>, and the first connection port <NUM> is connected to the operation switching valve <NUM>. After a lapse of a predetermined delay time from the start of the return stroke of the fluid pressure cylinder <NUM>, the second module 10B switches the flow path of the control target fluid from the first flow path <NUM> to the second flow path <NUM> to reduce the flow rate of the control target fluid, thereby setting to the operation speed to the low second speed. The pilot flow path <NUM> of the second module 10B is connected to the second supply and discharge path <NUM> via a second intersection flow path 130B. That is, the pilot fluid of the second module 10B is supplied from the second supply and discharge path <NUM> on the opposite side.

The second speed adjusting unit <NUM> and the first module 10A are connected to the second supply and discharge path <NUM>. The second speed adjusting unit <NUM> is configured in the same manner as the first speed adjusting unit <NUM>, and configures a meter-out speed controller that allows the flow in the direction of being supplied to the fluid pressure cylinder <NUM> to pass therethrough without resistance and regulates the flow in the opposite direction. The second speed adjusting unit <NUM> regulates an operation speed at the high first speed in a drive stroke in which the piston rod 120b of the fluid pressure cylinder <NUM> is extended.

The first module 10A is connected between the second speed adjusting unit <NUM> and the operation switching valve <NUM> in the second supply and discharge path <NUM>. The configuration of the first module 10A is similar to that of the second module 10B. The pilot flow path <NUM> of the first module 10A is connected to the first supply and discharge path <NUM> via a first intersection flow path 130A. As described above, the pilot flow paths <NUM> of the first module 10A and the second module 10B are connected to the supply and discharge paths <NUM> and <NUM>, respectively, on the opposite sides so as to cross each other.

Note that the first speed adjusting unit <NUM> and the second speed adjusting unit <NUM> are not limited to meter-out speed controllers, and may be configured as meter-in speed controllers by connecting the check valves 126a and 128a in opposite directions.

The operation switching valve <NUM> is similar to the operation switching valve <NUM> described with reference to <FIG>. The first port <NUM> of the operation switching valve <NUM> is connected to the second supply and discharge path <NUM>, the second port <NUM> is connected to the first supply and discharge path <NUM>, the third port <NUM> and the fifth port <NUM> are connected to the fluid discharge unit <NUM>, and the fourth port <NUM> is connected to the fluid supply source <NUM>.

The circuit configuration of the flow rate controller <NUM> according to the present embodiment is as described above. Further, the first module 10A and the second module 10B may be configured as an integrated valve unit <NUM>. Hereinafter, the valve unit <NUM> will be described with reference to <FIG> and <FIG>.

As shown in <FIG>, the valve unit <NUM> is configured by connecting two modules, i.e., the first module 10A and the second module 10B, each having the body <NUM>. The internal configuration of each of the first module 10A and the second module 10B is the same as that of the time delay valve <NUM> in <FIG>. However, as shown in <FIG>, a flow path connecting member <NUM> is provided in order to connect the pilot flow paths <NUM> of the first module 10A and the second module 10B to the supply and discharge paths <NUM> and <NUM> on the opposite side so as to cross each other.

The flow path connecting member <NUM> includes the first intersection flow path 130A that connects the connection port <NUM> of the second module 10B and the pilot flow path <NUM> of the first module 10A, and the second intersection flow path 130B that connects the connection port <NUM> of the first module 10A and the pilot flow path <NUM> of the second module 10B. The flow path connecting member <NUM> is connected to the pilot flow paths <NUM> so as to be sandwiched between the first intersection flow path 130A and the second intersection flow path 130B. In the second module 10B, respective holes are drilled in the sealing wall 56a of the connection port <NUM> on an opening portion 12e2 side and the sealing wall 36a of the pilot flow path <NUM> on the opening portion 12e2 side. In addition, in the first module 10A, respective holes are drilled in the sealing wall 56a of the connection port <NUM> on an opening portion 12e1 side and the sealing wall 36a of the pilot flow path <NUM> on the opening portion 12e1 side.

As shown in <FIG>, both side portions of the first module 10A and the second module 10B are covered with side plates 50A, and connected by bolts. A sealing member (not shown) is provided at a portion of the side plate 50A corresponding to the pilot flow path <NUM>, and the opening portion of the pilot flow path <NUM> is sealed by the side plate 50A.

The flow rate controller <NUM> according to the present embodiment is configured as described above, and the operations and actions will be described below.

In <FIG>, the horizontal axis indicates the passage of time, and the operation of controlling the flow rate of the control target fluid is performed in accordance with the switching operation of the operation switching valve <NUM>. A valve signal indicates the switching state of the operation switching valve <NUM> of the flow rate controller <NUM>. In an "ON" state, the first supply and discharge path <NUM> is connected to the fluid supply source <NUM>, and in an "OFF" state, the second supply and discharge path <NUM> is connected to the fluid supply source <NUM>.

A cylinder stroke indicates a stroke direction of the fluid pressure cylinder <NUM>, "DRIVE" indicates that a drive stroke for extending the piston rod 120b is performed, and "RETURN" indicates that a return stroke for pulling in the piston rod 120b is performed.

In the first module 10A and the second module 10B in <FIG>, "<FIG>" indicates that the spool <NUM> is at the first position, and "<NUM>" indicates that the spool <NUM> is at the second position. That is, "<NUM>" in the first module 10A and the second module 10B indicates that the flow path is the first flow path <NUM>, and "<NUM>" in the first module 10A and the second module 10B indicates that the flow path is the second flow path <NUM>. Each of the ranges indicated by arrows in the drawing is a delay time until the spools <NUM> of the first module 10A and the second module 10B are switched due to switching of the operation switching valve <NUM>, and is operation timing in which the influence of supply pressure of the pilot fluid may be exerted.

Hereinafter, the operation of the flow rate controller <NUM> when the valve signal of the operation switching valve <NUM> is switched from OFF to ON will be described.

As shown in <FIG>, when the valve signal of the operation switching valve <NUM> is switched from OFF to ON, the first port <NUM> and the fourth port <NUM> of the operation switching valve <NUM> are connected to each other, and the second supply and discharge path <NUM> is connected to the fluid supply source <NUM>. The control target fluid is supplied to the fluid pressure cylinder <NUM> via the second module 10B to start the drive stroke. Note that the operation of the first supply and discharge path <NUM> and the second module 10B during the drive stroke is the same as the operation of the first module 10A of the second supply and discharge path <NUM> during the return stroke described with reference to <FIG> and <FIG>, and thus the description thereof is omitted here.

Immediately before the valve signal of the operation switching valve <NUM> is switched from OFF to ON, the switching valve <NUM> of the first module 10A is located at the first position which is the initial position, and the pilot fluid is released from the drive mechanism <NUM> and the volume portion <NUM>. As shown in <FIG>, at the first position of the switching valve <NUM>, the flow path of the control target fluid in the first module 10A is the first flow path <NUM>, and the flow rate of the fluid discharged via the first supply and discharge path <NUM> is regulated only by the first speed adjusting unit <NUM>.

When the signal of the operation switching valve <NUM> is switched from OFF to ON, the pilot fluid in the first supply and discharge path <NUM> flows into the pilot flow path <NUM> through the first intersection flow path 130A. A portion of the pilot fluid is supplied to the compensation mechanism <NUM> through the compensation flow path <NUM>, and the compensation mechanism <NUM> generates a biasing force having a magnitude corresponding to the supply pressure of the pilot fluid. The pilot fluid in the pilot flow path <NUM> flows into the volume portion <NUM> while being regulated by the delay throttle valve <NUM>, and the pressure of the pilot fluid acting on the drive mechanism <NUM> gradually increases.

At timing when the biasing force of the drive mechanism <NUM> exceeds the biasing forces of the biasing member <NUM> and the compensation mechanism <NUM>, the switching valve <NUM> is switched to the second position as shown in <FIG>. The flow rate of the fluid discharged via the first supply and discharge path <NUM> is further throttled by the first throttle valve <NUM> provided in the second flow path <NUM> of the first module 10A in addition to the second speed adjusting unit <NUM>. As a result, the operation speed of the fluid pressure cylinder <NUM> is switched to the low second speed.

Here, with reference to <FIG> and <FIG>, a description will be given of results obtained by examining the charging characteristics indicating changes in charge pressures, which are pressures of the pilot fluid acting on the drive mechanism <NUM> of the first module 10A, and loci indicating changes over time in the stroke positions of the fluid pressure cylinder <NUM>, with respect to each of Comparative Example <NUM> and the present embodiment. Here, the results of supplying compressed air at pressures of <NUM> MPa, <NUM> MPa, and <NUM> MPa from the fluid supply source <NUM> are shown.

Comparative Example <NUM> shown in <FIG> shows a result of a case where the flow rate controller is configured by a time delay valve not including the compensation mechanism <NUM>. Attention is paid to the loci of the fluid pressure cylinder <NUM> when the flow rate controller of Comparative Example <NUM> is used. In this flow rate controller, the delay throttle valve <NUM> is adjusted so that the pressure of the fluid supply source <NUM> becomes optimum at <NUM> MPa. However, if the fluid supply source <NUM> increases or decreases by ±<NUM> MPa, the adjustment becomes improper, causing bouncing or the like at the end of the stroke of the fluid pressure cylinder <NUM> and increasing the variation in the timing of the end of the stroke. As described above, in the flow rate controller of Comparative Example <NUM> that does not include the compensation mechanism <NUM>, the variation in the stroke end time of the fluid pressure cylinder <NUM> becomes large.

The fluid pressure cylinder <NUM> is used by being incorporated in a production line of a factory. If the variation in the stroke end time of the fluid pressure cylinder <NUM> is large, there is a concern that interference may occur between a member connected to the fluid pressure cylinder <NUM> and other devices. From the viewpoint of preventing such interference, it is necessary to provide a relatively large safety margin when setting the valve signal for operating the fluid pressure cylinder <NUM>. As a result, the cycle time of the fluid pressure cylinder <NUM> is increased.

As shown in <FIG>, in the first module 10A of the flow rate controller <NUM> of the present embodiment, a step appears near <NUM> seconds in each of the charging characteristics of the first module 10A. This step is caused by the movement of the spool <NUM> of the switching valve <NUM>, and indicates the timing at which the switching valve <NUM> of the first module 10A switches. As shown in the drawing, the time at which the steps of the charging characteristics occur hardly change from <NUM> MPa to <NUM> MPa, and it is understood that the variation of the delay time is suppressed.

Focusing on the loci of the fluid pressure cylinder <NUM> in <FIG>, it can be seen that the variation in the loci of the fluid pressure cylinder <NUM> is suppressed, and the variation width in the end time of the stroke of the piston 120a is smaller than that in Comparative Example <NUM>. As described above, by using the flow rate controller <NUM> of the present embodiment, it is possible to suppress the variation in the loci of the fluid pressure cylinder <NUM> due to the pressure fluctuation of the fluid supply source <NUM>. Therefore, it is possible to reduce wasteful waiting time of the switching of the valve signal and to shorten the cycle time of the fluid pressure cylinder <NUM>.

Next, the operation of the flow rate controller <NUM> when the valve signal of the operation switching valve <NUM> is switched from "ON" to "OFF" will be described.

As shown in <FIG>, when the valve signal of the operation switching valve <NUM> is switched from ON to OFF, the second supply and discharge path <NUM> is connected to the fluid discharge unit <NUM>, and the first supply and discharge path <NUM> is connected to the fluid supply source <NUM>. Note that the operation of the first supply and discharge path <NUM> and the second module 10B is the same as the operation of the first module 10A described with reference to <FIG> and <FIG>, and the description thereof will be omitted. Immediately after the valve signal of the operation switching valve <NUM> is switched from "ON" to "OFF", the volume portion <NUM> of the first module 10A is charged with the pilot fluid, and the switching valve <NUM> is held at the second position by the action of the biasing force of the drive mechanism <NUM>.

Thereafter, when a predetermined time elapses, the pilot fluid charged in the compensation mechanism <NUM> and the volume portion <NUM> is discharged to the first supply and discharge path <NUM>. In addition, a part of the control target fluid in the second supply and discharge path <NUM> flows into the return mechanism <NUM> through the return flow path <NUM>. At timing when the pressure of the pilot fluid in the volume portion <NUM> decreases and the biasing force of the drive mechanism <NUM> falls below the biasing forces of the biasing member <NUM> and the return mechanism <NUM>, the switching valve <NUM> returns to the first position as shown in <FIG>. Then, the control target fluid is supplied to the fluid pressure cylinder <NUM> through the second module 10B, and the stroke of the fluid pressure cylinder <NUM> is started.

As described above, since the stroke of the fluid pressure cylinder <NUM> is started at the timing at which the switching valve <NUM> returns to the first position, if the return timing of the switching valve <NUM> varies, the stroke of the fluid pressure cylinder <NUM> varies. The amount of pilot fluid charged in the volume portion <NUM> increases or decreases in accordance with the supply pressure of the fluid supply source <NUM>. On the other hand, in the present embodiment, since the biasing force corresponding to the supply pressure of the fluid supply source <NUM> is added to the biasing force of the biasing member <NUM> through the return mechanism <NUM>, it is possible to cancel the influence of the increase or decrease in the amount of the pilot fluid charged in the volume portion <NUM> by the return mechanism <NUM>.

Hereinafter, with reference to <FIG> and <FIG>, a description will be given of results obtained by examining the charging characteristics of the first module 10A and the loci of the stroke of the fluid pressure cylinder <NUM> when the operation switching valve <NUM> is switched from "ON" to "OFF" with respect to each of the flow rate controller of Comparative Example <NUM> and the flow rate controller <NUM> of the present embodiment. Here, the results are shown when the supply pressures of the compressed air of the fluid supply source <NUM> are <NUM> MPa, <NUM> MPa, and <NUM> MPa. The flow rate controller of Comparative Example <NUM> is constituted by a time delay valve that does not include the return mechanism <NUM>.

As shown in <FIG>, in the flow rate controller of Comparative Example <NUM>, the pilot pressure of the volume portion <NUM> tends to decrease earlier in the order of <NUM> MPa, <NUM> MPa, and <NUM> MPa for the pressure of the fluid supply source <NUM>. In addition, the loci of the fluid pressure cylinder <NUM> rise after a delay time ranging from <NUM> seconds to <NUM> seconds after the valve signal is switched. Thus, there is variation in the time until the piston 120a of the fluid pressure cylinder <NUM> starts to operate. As described above, in the flow rate controller of Comparative Example <NUM> configured by the time delay valve without the return mechanism <NUM>, it is found that the start timing of the stroke of the fluid pressure cylinder <NUM> is greatly affected by the fluid supply source <NUM>.

On the other hand, as shown in <FIG>, in the flow rate controller <NUM> of the present embodiment, although the charging characteristics show the same tendency as those of the flow rate controller of Comparative Example <NUM>, the loci of the fluid pressure cylinder <NUM> rise about <NUM> seconds after the valve signal is switched, and it can be seen that the delay time until the start of the stroke of the fluid pressure cylinder <NUM> is shorter than that of Comparative Example <NUM>. In addition, even if the supply pressure of the fluid supply source <NUM> changes in the range of <NUM> to <NUM> MPa, the rising time of each of the loci does not change, and it can be seen that the start timing of the stroke of the fluid pressure cylinder <NUM> is not affected by the pressure fluctuation of the fluid supply source <NUM>.

From the above results, it can be confirmed that, according to the flow rate controller <NUM> of the present embodiment, the delay time until the start of the stroke of the fluid pressure cylinder <NUM> can be shortened, and that the variation in the stroke start timing of the fluid pressure cylinder <NUM> can be suppressed even when the supply pressure of the fluid supply source <NUM> fluctuates. Therefore, according to the flow rate controller <NUM> of the present embodiment, it is possible to shorten the waiting time set in the valve signal and to shorten the cycle time.

The flow rate controller <NUM> of the present embodiment realizes the following advantageous effects.

The flow rate controller <NUM> includes the first supply and discharge path <NUM> configured to supply and discharge fluid to and from the head-side port (one port) <NUM> of the fluid pressure cylinder <NUM>, the second supply and discharge path <NUM> configured to supply and discharge fluid to and from rod-side port (another port) <NUM> of the fluid pressure cylinder <NUM>, the operation switching valve <NUM> configured to switch and connect the fluid supply source <NUM> and the fluid discharge unit <NUM> to the first supply and discharge path <NUM> and the second supply and discharge path <NUM>, the fluid supply source <NUM> being configured to supply the control target fluid and the fluid discharge unit <NUM> being configured to discharge fluid, and the time delay valves (first module 10A and second module 10B) provided in the first supply and discharge path <NUM> and the second supply and discharge path <NUM>, respectively, wherein each of the time delay valves (first module 10A and second module 10B) includes the switching valve <NUM> configured to be switched between the first position and the second position, the biasing member <NUM> configured to bias the switching valve <NUM> toward the first position, the drive mechanism <NUM> configured to bias the switching valve <NUM> toward the second position under the action of the supply pressure of the pilot fluid, the pilot flow path <NUM> configured to guide the pilot fluid to the drive mechanism <NUM>, and the delay mechanism <NUM> configured to delay the switching timing of the switching valve <NUM>, and wherein the delay mechanism <NUM> includes the first throttle valve <NUM> provided in the pilot flow path <NUM>, and the compensation mechanism <NUM> configured to bias the switching valve <NUM> toward the first position under the action of the supply pressure of the pilot fluid.

According to the above-described configuration, even if the supply pressure of the pilot fluid fluctuates, it is possible to suppress the variation in the delay time of each of the first module 10A and the second module 10B and to suppress variation in the loci of the fluid pressure cylinder <NUM>. As a result, the waiting time at the time of switching the operation of the fluid pressure cylinder <NUM> can be reduced, and the cycle time of the fluid pressure cylinder <NUM> can be shortened to improve the operation speed.

Claim 1:
A time delay valve (<NUM>) comprising:
a switching valve (<NUM>) configured to be switched between a first position and a second position;
a biasing member (<NUM>) configured to bias the switching valve (<NUM>) toward the first position;
a drive mechanism (<NUM>) configured to bias the switching valve (<NUM>) toward the second position under an action of a supply pressure of a pilot fluid;
a pilot flow path (<NUM>) configured to guide the pilot fluid to the drive mechanism (<NUM>);
a delay mechanism (<NUM>) configured to delay switching timing of the switching valve (<NUM>);
a first flow path (<NUM>) configured to allow communication at the first position of the switching valve (<NUM>);
a second flow path (<NUM>) configured to allow communication at the second position of the switching valve (<NUM>);
a first throttle valve (<NUM>) provided in at least one of the first flow path (<NUM>) or the second flow path (<NUM>);
a return mechanism (<NUM>) configured to generate a biasing force opposite to that of the drive mechanism (<NUM>); and
a return flow path (<NUM>) branched from the first flow path (<NUM>) or the second flow path (<NUM>) and connected to the return mechanism (<NUM>),
wherein the switching valve (<NUM>) includes:
a spool (<NUM>); and
a sleeve (<NUM>) in which the spool (<NUM>) slides,
the drive mechanism (<NUM>) includes:
a drive piston chamber (<NUM>) provided at one end of the spool (<NUM>); and
a drive piston (<NUM>) configured to partition the drive piston chamber (<NUM>) into a first empty chamber (72a) and a second empty chamber (72b),
wherein the delay mechanism (<NUM>) includes:
a delay throttle valve (<NUM>) provided in the pilot flow path (<NUM>); and
a compensation mechanism (<NUM>) configured to bias the switching valve (<NUM>) toward the first position under an action of the supply pressure of the pilot fluid, and
wherein the drive piston (<NUM>) is formed integrally with the spool (<NUM>) includes:
a first pressure receiving surface (70a) on a side of the first empty chamber (72a), the first pressure receiving surface (70a) being configured to receive the supply pressure of the pilot fluid to generate the biasing force toward the second position;
a second pressure receiving surface (70b) that faces the second empty chamber (72b) and is provided on an opposite side from the first pressure receiving surface (70a), and
the compensation mechanism (<NUM>) is formed of the second pressure receiving surface (70b).