Patent Description:
A control valve configured to be switched by an action of a pilot pressure and to lead the pilot pressure to another device is known (see <CIT>). This control valve includes a spool slidably incorporated in a valve housing and a first pilot chamber and a second pilot chamber disposed by facing both ends of the spool, and the spool is moved by an action of a pilot pressure led to either one of the first pilot chamber and the second pilot chamber.

A signal pressure passage configured to lead the pilot pressure of the first pilot chamber or the second pilot chamber as a signal pressure of the other device is formed in the valve housing. A communication groove configured to allow the first pilot chamber and the signal pressure passage to communicate with each other when the pilot pressure is led to the first pilot chamber and the spool is moved and a communication hole configured to allow the second pilot chamber and the signal pressure passage to communicate with each other when the pilot pressure is led to the second pilot chamber and the spool is moved, are formed in the spool. A check valve configured to allow only flow from the second pilot chamber to the signal pressure passage is interposed in the communication hole.

A centering spring configured to apply a spring force to one end portion of the spool is accommodated in the first pilot chamber. A base end portion of a rod extending in the first pilot chamber is screwed and fastened to an opening on the one end portion of the spool. A pair of spring receiving members slidable along an outer periphery of the rod is accommodated in the first pilot chamber, and the centering spring is interposed between the pair of spring receiving members.

The check valve described in <CIT> can be constituted by a poppet portion configured to move in an axial direction and to open/close the communication hole and a spacer portion configured to regulate a moving amount of the poppet portion in the axial direction. In such configuration, when the pilot pressure is led to the second pilot chamber, the poppet portion is moved until it abuts to the spacer portion, and an open valve state is brought about. On the other hand, when the pilot pressure is led to the first pilot chamber, the poppet portion is seated on a seat portion of the communication hole, and a closed valve state is brought about.

However, in the check valve described in <CIT>, since the base end portion of the rod is screwed and fastened to the one end portion of the spool, when the pilot pressure is led to the first pilot chamber, there is a concern that a working oil enters into the check valve side from the first pilot chamber through a connection portion (screwed/fastened portion) between the one end portion of the spool and the rod. If the working oil enters into the check valve side, a pressure in a space between a rear surface (a surface on a side opposite to the surface in contact with the poppet portion) of the spacer portion and an end surface of the base end portion of the rod rises.

As a result, the spacer portion moves in the axial direction and presses the poppet portion so as to press the poppet portion onto the seat portion. After that, when the first pilot chamber is connected to a tank, the pressure in the space between the rear surface of the spacer portion and the end surface of the base end portion of the rod goes out to the tank through the connection portion (screwed/fastened portion) between the one end portion of the spool and the rod. However, since it takes time for the pressure in the space between the rear surface of the spacer portion and the end surface of the base end portion to lower to a tank pressure, the pressure remains in the space on the rear surface side of the spacer portion. If the pressure remains in the space on the rear surface side of the spacer portion when the pilot chamber is led to the second pilot chamber, a valve opening operation of the check valve according to the pressure in the second pilot chamber is inhibited, and responsiveness of the check valve is deteriorated, which is a problem. Document <CIT> is a family member in English of document <CIT>.

The present invention has an object to improve responsiveness of a check valve.

This object is solved by the subject matter of claim <NUM>.

A control valve <NUM> according to a first embodiment of the present invention will be described by referring to <FIG>, <FIG>.

The control valve <NUM> switches supply/discharge of a working fluid with respect to an actuator and controls an operation of the actuator. An example in which a working oil is used as the working fluid will be described, but other fluids such as a working water and the like may be used as the working fluid.

<FIG> is a sectional view illustrating the control valve <NUM>. As illustrated in <FIG>, the control valve <NUM> includes a valve housing <NUM>, a spool <NUM> slidably incorporated in the valve housing <NUM>, a first pilot chamber <NUM> and a second pilot chamber <NUM> respectively disposed by facing each of both ends of the spool <NUM>, and a centering spring <NUM> as a biasing member accommodated in the first pilot chamber <NUM> and configured to apply a spring force to one end portion of the spool <NUM>.

A rod <NUM> extending in the first pilot chamber <NUM> is connected to the one end portion of the spool <NUM>. A pair of spring receiving members <NUM> and <NUM> slidable along an outer periphery of the rod <NUM> is accommodated in the first pilot chamber <NUM>, and the centering spring <NUM> is interposed between the pair of spring receiving members <NUM> and <NUM>.

A pair of actuator ports <NUM> and <NUM> communicating with the actuator is formed in the valve housing <NUM>.

When a pilot pressure acts on neither the first pilot chamber <NUM> nor the second pilot chamber <NUM>, the first pilot chamber <NUM> and the second pilot chamber <NUM> communicate with a tank maintained at an atmospheric pressure. As a result, the spool <NUM> is held at a neutral position by the biasing force of the centering spring <NUM>. In this state, supply/discharge of the working oil to/from the actuator through the actuator ports <NUM> and <NUM> is shut off, and the actuator is held in a stopped state.

When the pilot pressure is led to either one of the first pilot chamber <NUM> and the second pilot chamber <NUM> by a lever operation by a worker, the spool <NUM> is moved against the spring force of the centering spring <NUM> by an action of the pilot pressure, and the actuator is operated. At this time, the other of the first pilot chamber <NUM> and the second pilot chamber <NUM> communicates with the tank.

More specifically, when the pilot pressure is led to the first pilot chamber <NUM>, and the second pilot chamber <NUM> communicates with the tank, the spool <NUM> is moved to the right direction in <FIG> against the spring force of the centering spring <NUM>. When the spool <NUM> is moved to the right direction in <FIG>, the actuator port <NUM> communicates with a pump as a hydraulic pressure supply source through a pump port <NUM>, and the actuator port <NUM> communicates with the tank through a tank port <NUM>. As a result, the working oil discharged from a pump is supplied to the actuator through the actuator port <NUM>, the working oil is discharged from the actuator to the tank through the actuator port <NUM>, and the actuator is operated in one direction.

When the pilot pressure is led to the second pilot chamber <NUM>, and the first pilot chamber <NUM> communicates with the tank, the spool <NUM> is moved to the left direction in <FIG> against the spring force of the centering spring <NUM>. When the spool <NUM> is moved to the left direction in <FIG>, the actuator port <NUM> communicates with the pump through a pump port <NUM>, and the actuator port <NUM> communicates with the tank through the tank port <NUM>. As a result, the working oil discharged from the pump is supplied to the actuator through the actuator port <NUM>, the working oil is discharged from the actuator to the tank through the actuator port <NUM>, and the actuator is operated to the other direction.

A signal pressure passage <NUM> configured to lead the pilot pressure in the first pilot chamber <NUM> or the second pilot chamber <NUM> to another device other than the control valve <NUM> as a signal pressure is formed in the valve housing <NUM>.

A communication groove <NUM> opened in the first pilot chamber <NUM> is annularly formed in an outer peripheral surface of the one end portion of the spool <NUM>. The communication groove <NUM> allows the first pilot chamber <NUM> and the signal pressure passage <NUM> to communicate with each other when the spool <NUM> is at the neutral position.

When the pilot pressure is led to the first pilot chamber <NUM>, and the spool <NUM> is moved to the right direction in <FIG>, the communication groove <NUM> keeps the communication state with the signal pressure passage <NUM> and allows the first pilot chamber <NUM> and the signal pressure passage <NUM> to communicate with each other. On the other hand, when the pilot pressure is led to the second pilot chamber <NUM> and the spool <NUM> is moved to the left direction in <FIG>, the communication groove <NUM> is separated from the signal pressure passage <NUM> and shuts off the communication between the first pilot chamber <NUM> and the signal pressure passage <NUM>.

A communication hole <NUM> configured to allow the second pilot chamber <NUM> and the signal pressure passage <NUM> to communicate with each other is formed in the spool <NUM>. A check valve <NUM> configured to allow only the flow from the second pilot chamber <NUM> to the signal pressure passage <NUM> is interposed in the communication hole <NUM>.

A valve accommodating portion <NUM> opened in the one end surface (left end surface in <FIG>) of the spool <NUM> is formed in the communication hole <NUM>, and the check valve <NUM> is accommodated in this valve accommodating portion <NUM>. The communication hole <NUM> has a first passage 20a extending along the axial direction from the other end surface (right end surface in <FIG>) of the spool <NUM>, a part of the valve accommodating portion <NUM>, and a second passage 20b extending over the outer periphery of the spool <NUM> from the valve accommodating portion <NUM>. The axial direction refers to a center axis direction of the spool <NUM>, that is, a moving direction of the spool <NUM>.

An opening of the valve accommodating portion <NUM> is closed by the rod <NUM> as a closing member facing inside of the first pilot chamber <NUM>. The rod <NUM> is screwed and fastened to the opening of the valve accommodating portion <NUM>.

<FIG> is an enlarged sectional view illustrating the one end portion of the spool <NUM> in an enlarged manner, and illustration of the valve housing <NUM> is omitted. As illustrated in <FIG>, the check valve <NUM> has a poppet portion <NUM> configured to open/close the communication hole <NUM>, a spacer portion <NUM> configured to regulate the moving amount of the poppet portion <NUM> in an open direction and an O-ring <NUM> as a seal member which seals a space between the spacer portion <NUM> and the valve accommodating portion <NUM>.

The valve accommodating portion40 has a first accommodating hole <NUM> in which the poppet portion <NUM> is accommodated, a second accommodating hole <NUM> in which the spacer portion <NUM> is accommodated, and a third accommodating hole <NUM> in which a base end portion <NUM> of the rod <NUM> is accommodated. The first accommodating hole <NUM>, the second accommodating hole <NUM>, and the third accommodating hole <NUM> have a circular opening section, respectively, and are formed coaxially, respectively.

A male screw to be screwed with a female screw formed on an inner periphery of the third accommodating hole <NUM> is formed on an outer periphery of the base end portion <NUM> of the rod <NUM>. That is, the outer periphery of the base end portion <NUM> of the rod <NUM> and the inner periphery of the third accommodating hole <NUM> of the valve accommodating portion <NUM> constitute a screw fastening portion <NUM> of the rod <NUM> and the valve accommodating portion <NUM>.

The second accommodating hole <NUM> has a large-diameter opening portion 42a, a small-diameter opening portion 42b, and a taper portion 42c configured to connect the large-diameter opening portion 42a and the small-diameter opening portion 42b. The large-diameter opening portion 42a, the small-diameter opening portion 42b, and the taper portion 42c have a circular section, respectively, and are formed coaxially, respectively. An inner diameter of the large-diameter opening portion 42a is larger than the inner diameter of the small-diameter opening portion 42b, and the taper portion 42c is inclined so that the inner diameter thereof becomes smaller from a connection portion with the large-diameter opening portion 42a toward a connection portion with the small-diameter opening portion 42b.

The taper portion 42c is a contact portion to which a projecting portion 63a of the spacer portion <NUM> can abut, which will be described later. Though details will be described later, when the projecting portion 63a of the spacer portion <NUM> abuts to the taper portion 42c, movement of the spacer portion <NUM> toward the poppet portion <NUM> side is regulated.

The first accommodating hole <NUM> has a sliding hole 41a through which the poppet portion <NUM> slides and a seat portion 41b on which the poppet portion <NUM> can be seated. The inner diameter of the sliding hole 41a is smaller than the inner diameter of the small-diameter opening portion 42b of the second accommodating hole <NUM>.

<FIG> is a sectional view of the poppet portion <NUM>. As illustrated in <FIG>, the poppet portion <NUM> has a seated portion <NUM> having a conical shape and seated on the seat portion 41b provided in the communication hole <NUM>, a sliding portion <NUM> slidable along the sliding hole 41a, a cylinder portion <NUM> configured to connect the seated portion <NUM> and the sliding portion <NUM>, a first internal passage <NUM> opened in a rear surface 50a which is an end surface on a side opposite to the seated portion <NUM>, and a first through hole <NUM> opened in the outer peripheral surface of the cylinder portion <NUM> and communicating with the first internal passage <NUM>. An outer diameter of the cylinder portion <NUM> is smaller than the outer diameter of the sliding portion <NUM>. Thus, as illustrated in <FIG>, a communication path for the working oil is formed between the outer peripheral surface of the cylinder portion <NUM> and the inner peripheral surface of the sliding hole 41a of the first accommodating hole <NUM>.

<FIG> is a sectional view of the spacer portion <NUM>. As illustrated in <FIG>, the spacer portion <NUM> has an abutting end portion <NUM> abutting to the poppet portion <NUM>, a sliding portion <NUM> slidable along the small-diameter opening portion 42b, and a base end portion <NUM> abutting to the taper portion 42c. The abutting end portion <NUM>, the sliding portion <NUM>, and the base end portion <NUM> have a circular section, respectively, and are formed coaxially, respectively.

As illustrated in <FIG>, in the spacer portion <NUM>, when the poppet portion <NUM> is in the open valve state, a distal end surface 60a thereof abuts to the poppet portion <NUM>, and a rear surface 60b on a side opposite to the distal end surface 60a abuts to the base end portion <NUM> of the rod <NUM>.

The spacer portion <NUM> is movable in the axial direction within a range from a position abutting to the base end portion <NUM> of the rod <NUM> (see <FIG>) to a position abutting to the taper portion 42c (see <FIG>). The rear surface 50a of the poppet portion <NUM> abuts to the distal end surface 60a of the spacer portion <NUM>, and the rear surface 60b of the spacer portion <NUM> abuts to the base end portion <NUM> of the rod <NUM>, whereby the moving amount of the poppet portion <NUM> to an open direction is limited. That is, the base end portion <NUM> of the rod <NUM> regulates movement of the spacer portion <NUM> by the pilot pressure from the second pilot chamber <NUM>. Regardless of the position of the spacer portion <NUM>, in a state where the rear surface 50a of the poppet portion <NUM> abuts to the distal end surface 60a of the spacer portion <NUM>, an open amount of the poppet portion <NUM> is sufficiently ensured when the pilot pressure is led to the second pilot chamber <NUM>. More specifically, in both the state where the spacer portion <NUM> abuts to the base end portion <NUM> of the rod <NUM> (see <FIG>) and the state where the spacer portion <NUM> abuts to the taper portion 42c (see <FIG>), the open amount of the poppet portion <NUM> is sufficiently ensured when the pilot pressure is led to the second pilot chamber <NUM>.

The outer diameter of the base end portion <NUM> of the spacer portion <NUM> is larger than the outer diameter of the sliding portion <NUM>. In other words, the projecting portion 63a protruding outward than the sliding portion <NUM> in a radial direction is formed on the base end portion <NUM> of the spacer portion <NUM>. The projecting portion 63a is formed over the entire periphery of the base end portion <NUM>.

A second internal passage <NUM> opened in the distal end surface 60a which is an end surface facing the poppet portion <NUM>, and a second through hole <NUM> opened in the outer peripheral surface of the abutting end portion <NUM> and communicating with the second internal passage <NUM>, are formed in the abutting end portion <NUM> of the spacer portion <NUM>. The second internal passage <NUM> is opened by facing the opening of the first internal passage <NUM> of the poppet portion <NUM>. The outer diameter of the abutting end portion <NUM> is smaller than the outer diameter of the sliding portion <NUM>. Thus, as illustrated in <FIG>, a communication path for the working oil is formed between the outer peripheral surface of the abutting end portion <NUM> and the inner peripheral surface of the small-diameter opening portion 42b of the second accommodating hole <NUM>.

An annular groove 62a is formed in the sliding portion <NUM>, and an O-ring <NUM> is attached to this groove 62a. The O-ring <NUM> provided in the spacer portion <NUM> is disposed so as to fill a gap between the small-diameter opening portion 42b of the second accommodating hole <NUM> and the spacer portion <NUM>. Therefore, the valve accommodating portion <NUM> is divided by the O-ring <NUM> into a space S1 on the poppet portion <NUM> side, that is, on the distal end surface 60a side (right side in <FIG>) of the spacer portion <NUM> and a space S2 on the base end portion <NUM> side of the rod <NUM>, that is, on the rear surface 60b side (left side in <FIG>) of the spacer portion <NUM>. The space S1 constitutes a part of the aforementioned communication hole <NUM>.

One end of the aforementioned second passage 20b is connected to the inner peripheral surface of the small-diameter opening portion 42b in the second accommodating hole <NUM> defining the space S1. That is, the second passage 20b formed in the spool <NUM> is a communication path which allows the second through hole <NUM> of the spacer portion <NUM> and the signal pressure passage <NUM> (see <FIG>) of the valve housing <NUM> to communicate with each other.

Subsequently, an operation of the control valve <NUM> will be described.

As illustrated in <FIG>, when the pilot pressure is led to the first pilot chamber <NUM>, and the spool <NUM> is moved to the right direction in <FIG> by the action of the pilot pressure, the actuator port <NUM> communicates with the pump, and the actuator port <NUM> communicates with the tank. At this time, since the communication groove <NUM> keeps the communication state with the signal pressure passage <NUM>, the pilot pressure of the first pilot chamber <NUM> is led to the signal pressure passage <NUM> through the communication groove <NUM>.

Since the check valve <NUM> is interposed in the communication hole <NUM>, the pilot pressure of the first pilot chamber <NUM> does not go out to the tank through the signal pressure passage <NUM>, the communication hole <NUM>, and the second pilot chamber <NUM>. As the pilot pressure of the first pilot chamber <NUM> acts on the poppet portion <NUM> through the communication groove <NUM>, the signal pressure passage <NUM>, and the second passage 20b, and the seated portion <NUM> of the poppet portion <NUM> is seated on the seat portion 41b, the check valve <NUM> is brought to the closed valve state (see <FIG>).

After the spool <NUM> has moved to the right direction in <FIG>, when the first pilot chamber <NUM> communicates with the tank, the spool <NUM> is returned to the neutral position illustrated in <FIG>. Since the first pilot chamber <NUM> communicates with the signal pressure passage <NUM> through the communication groove <NUM>, the pressure of the signal pressure passage <NUM> goes out to the tank through the communication groove <NUM> and the first pilot chamber <NUM>. Therefore, the pressure does not remain in the signal pressure passage <NUM>, and another device connected to the signal pressure passage <NUM> does not erroneously operate.

When the pilot pressure is led to the second pilot chamber <NUM>, and the spool <NUM> is moved to the left direction in <FIG> by the action of the pilot pressure, the actuator port <NUM> communicates with the pump, and the actuator port <NUM> communicates with the tank. At this time, the pilot pressure led to the second pilot chamber <NUM> acts on the check valve <NUM> through the first passage 20a of the communication hole <NUM>, pushes open the poppet portion <NUM> of the check valve <NUM> and is led to the signal pressure passage <NUM>.

More specifically, the pilot pressure of the second pilot chamber <NUM> is led to the signal pressure passage <NUM> through the first passage 20a of the spool <NUM>, a space between the seated portion <NUM> of the check valve <NUM> and the seat portion 41b, a space between the sliding hole 41a and the outer periphery of the cylinder portion <NUM> of the poppet portion <NUM>, the first through hole <NUM> of the poppet portion <NUM>, the first internal passage <NUM> of the poppet portion <NUM>, the second internal passage <NUM> of the spacer portion <NUM>, the second through hole <NUM> of the spacer portion <NUM>, a space between the outer periphery of the abutting end portion <NUM> of the spacer portion <NUM> and the small-diameter opening portion 42b, and the second passage 20b of the spool <NUM>. As described above, in this embodiment, the pilot pressure of the second pilot chamber <NUM> can be led to the signal pressure passage <NUM> (see <FIG>) through the first internal passage <NUM> of the poppet portion <NUM> and the second internal passage <NUM> of the spacer portion <NUM>.

At this time, since the communication groove <NUM> illustrated in <FIG> is separated from the signal pressure passage <NUM>, the pilot pressure of the second pilot chamber <NUM> does not go out to the tank from the first pilot chamber <NUM> through the signal pressure passage <NUM>.

After the spool <NUM> has moved to the left direction in <FIG>, when the second pilot chamber <NUM> communicates with the tank, the spool <NUM> is returned to the neutral position illustrated in <FIG>. As a result, since the communication groove <NUM> communicates with the signal pressure passage <NUM>, the pressure of the signal pressure passage <NUM> goes out to the tank through the communication groove <NUM> and the first pilot chamber <NUM>. Therefore, the pressure does not remain in the signal pressure passage <NUM>, and another device connected to the signal pressure passage <NUM> does not erroneously operate.

A structure configured to regulate the movement of the spacer portion <NUM> will be described in detail by referring to <FIG> is a view for explaining that the movement of the spacer portion <NUM> is regulated, and similarly to <FIG>, the one end portion of the spool <NUM> of the control valve <NUM> is illustrated in an enlarged manner. As described above, the projecting portion 63a protruding outward in the radial direction is formed on the base end portion <NUM> of the spacer portion <NUM>, and the taper portion 42c as the abutting portion configured to abut to the projecting portion 63a is formed on the valve accommodating portion <NUM> of the spool <NUM>. Thus, as the projecting portion 63a abuts to the taper portion 42c, the movement of the spacer portion <NUM> toward the poppet portion <NUM> is limited.

As illustrated in <FIG>, in the closed valve state where the poppet portion <NUM> is seated on the seat portion 41b, a predetermined gap is formed between the distal end surface 60a of the spacer portion <NUM> and the rear surface 50a of the poppet portion <NUM> in the closed valve state. That is, the taper portion 42c is formed at the position separated from the seat portion 41b only by a predetermined distance so that, in the state where the projecting portion 63a of the spacer portion <NUM> abuts to the taper portion 42c, the gap is formed between the distal end surface 60a of the spacer portion <NUM> and the poppet portion <NUM> in the closed valve state. This gap is set to a sufficient length for the poppet portion <NUM> to perform an opening/closing operation.

As a result, the poppet portion <NUM> can perform the opening/closing operation even in the state where the projecting portion 63a of the spacer portion <NUM> abuts to the taper portion 42c. That is, even if the spacer portion <NUM> is held at the position which is the closest to the poppet portion <NUM> in the closed valve state, the poppet portion <NUM> is separated from the seat portion 41b, moved to the open direction until the poppet portion <NUM> abuts to the distal end surface 60a of the spacer portion <NUM>, and is brought into the open valve state.

The action and effect of this embodiment in which the movement of the spacer portion <NUM> in the axial direction is regulated will be described more specifically in comparison with a comparative example of this embodiment illustrated in <FIG> are views for explaining the operation of a check valve <NUM> of the control valve according to the comparative example of this embodiment, in which <FIG> illustrates a state where the check valve <NUM> is open, and <FIG> illustrates a state where the check valve <NUM> is closed. As illustrated in <FIG>, in the comparative example of this embodiment, the projecting portion 63a (see <FIG>, <FIG>, and <FIG>) protruding outward in the radial direction is not provided on a base end portion <NUM> of a spacer portion <NUM>. That is, the base end portion <NUM> and the sliding portion <NUM> have the same diameter.

As illustrated in <FIG>, when the pilot pressure is led to the second pilot chamber <NUM>, the poppet portion <NUM> is separated from the seat portion 41b, and the check valve <NUM> is brought into the open valve state. Since the spacer portion <NUM> is accommodated slidably in the axial direction in the small-diameter opening portion 42b, the spacer portion <NUM> is moved together with the poppet portion <NUM> to the left direction in the figure and abuts to the base end portion <NUM> of the rod <NUM>. As a result, the moving amount of the poppet portion <NUM> is regulated by the spacer portion <NUM>.

As illustrated in <FIG>, when the pilot pressure is led to the first pilot chamber <NUM>, the poppet portion <NUM> is seated on the seat portion 41b, and the check valve <NUM> is borough into the closed valve state. At this time, there is a concern that the working oil enters into the check valve <NUM> side from the first pilot chamber <NUM> through the screw fastening portion <NUM> which is a connection portion between the one end portion of the spool <NUM> and the rod <NUM>. When the pilot pressure is led to the first pilot chamber <NUM>, and the state where the second pilot chamber <NUM> communicates with the tank, that is, when the state where the pressure of the first pilot chamber <NUM> is higher than the pressure (tank pressure) of the second pilot chamber <NUM> is kept, the pressure is raised in the space S2 on the rear surface 960b side of the spacer portion <NUM>.

As a result, the spacer portion <NUM> is moved in the axial direction toward the poppet portion <NUM> in the closed valve state and presses the poppet portion <NUM> so as to press the poppet portion <NUM> onto the seat portion 41b. After that, when the first pilot chamber <NUM> communicates with the tank, the pressure in the space S2 on the rear surface 960b side of the spacer portion <NUM> goes out to the tank through the screw fastening portion <NUM> of the one end portion of the spool <NUM> and the rod <NUM>. However, it takes time for the pressure in the space S2 on the rear surface 960b side of the spacer portion <NUM> to lower to the tank pressure. Therefore, if the pilot pressure is led to the second pilot chamber <NUM> in the state (state where the pressure remains) where the pressure in the space S2 has not lowered to the tank pressure, the valve opening operation of the poppet portion <NUM> according to the pressure of the second pilot chamber <NUM> is inhibited by the spacer portion <NUM>, and responsiveness of the check valve <NUM> is deteriorated.

On the other hand, in this embodiment, when the pilot pressure is led to the first pilot chamber <NUM>, and the pilot pressure of the first pilot chamber <NUM> acts on the rear surface 60b of the spacer portion <NUM> as illustrated in <FIG>, the taper portion 42c as the abutting portion formed on the spool <NUM> abuts to the projecting portion 63a of the spacer portion <NUM>. As a result, movement of the spacer portion <NUM> in the axial direction toward the poppet portion <NUM> in the closed valve state is regulated. As described above, in this embodiment, the projecting portion 63a of the spacer portion <NUM> and the taper portion 42c of the spool <NUM> function as a movement regulating portion <NUM> configured to regulate movement of the spacer portion <NUM> toward the poppet portion <NUM>.

As a result, even in the state where the spacer portion <NUM> has moved to the maximum to the poppet portion <NUM> side, the gap is formed between the distal end surface 60a of the spacer portion <NUM> and the rear surface 50a of the poppet portion <NUM> in the closed valve state. As a result, when the pilot pressure is led to the second pilot chamber <NUM>, inhibition on the valve opening operation of the poppet portion <NUM> by the spacer portion <NUM> is prevented and thus, the pilot pressure of the second pilot chamber <NUM> is immediately led to the other device other than the control valve <NUM> through the signal pressure passage <NUM>. As described above, according to this embodiment, the responsiveness of the check valve <NUM> can be improved as compared with the check valve <NUM> in the comparative example.

According to the aforementioned embodiment, the subsequent actions and effects are exerted.

(<NUM>)The movement regulating portion <NUM> configured to regulate movement of the spacer portion <NUM> toward the poppet portion <NUM> is constituted by the projecting portion 63a formed on the spacer portion <NUM> and protruding outward in the radial direction of the spacer portion <NUM> and the taper portion 42c as the abutting portion formed on the spool <NUM> and abutting to the projecting portion 63a. As a result, even if the pilot pressure of the first pilot chamber <NUM> is led to the space S2 through the screw fastening portion <NUM>, and acts on the rear surface 60b of the spacer portion <NUM> when the pilot pressure is led to the first pilot chamber <NUM>, the movement of the spacer portion <NUM> toward the poppet portion <NUM> is regulated. As a result, since the gap is formed between the distal end surface 60a of the spacer portion <NUM> and the rear surface 50a of the poppet portion <NUM> in the closed valve state, when the pilot pressure is led to the second pilot chamber <NUM>, the inhibition on the valve opening operation of the poppet portion <NUM> by the spacer portion <NUM> is prevented. That is, according to this embodiment, the responsiveness of the check valve <NUM> can be improved.

(<NUM>)If entering of the working oil into the space S2 from the first pilot chamber <NUM> is to be prevented by providing a seal member at a portion where the rod <NUM> and the one end surface of the spool <NUM> abut to each other, there is a concern that an increase in manufacturing costs is incurred with an increase in the number of components and size. To the contrary, in this embodiment, the movement of the spacer portion <NUM> toward the poppet portion <NUM> can be regulated only by providing the projecting portion 63a on the spacer portion <NUM> and by providing the taper portion 42c as the abutting portion on the spool <NUM>, and the responsiveness of the check valve <NUM> can be improved while the increase in the manufacturing cost can be suppressed.

The aforementioned embodiment describes the example in which the projecting portion 63a abutting to the taper portion 42c is provided over the entire periphery of the base end portion <NUM> of the spacer portion <NUM>, but the present invention is not limited to that. Instead of the projecting portion 63a, a plurality of or a single rod-shaped projecting portion protruding outward in the radial direction may be provided on the base end portion <NUM> of the spacer portion <NUM>, for example, so that the movement of the spacer portion <NUM> may be regulated by causing this projecting portion to abut to the taper portion 42c.

The aforementioned embodiment describes the example in which the taper portion 42c is provided as the abutting portion to which the projecting portion 63a abuts, but the present invention is not limited to that. Instead of the taper portion 42c, a planar stepped portion orthogonal to the center axis of the spool <NUM> is provided, for example, so that the movement of the spacer portion <NUM> may be regulated by causing this stepped portion to abut to the projecting portion 63a.

The aforementioned embodiment describes the example in which the taper portion 42c as the abutting portion which abuts to the projecting portion 63a of the spacer portion <NUM> is formed on the spool <NUM>, but the present invention is not limited to that. A member having an abutting portion which abuts to the projecting portion 63a of the spacer portion <NUM> may be attached to the valve accommodating portion configured to accommodate the check valve <NUM>, for example.

The aforementioned embodiment describes the example in which movement of the spacer portion <NUM> is regulated when the pressure in the space S2 is raised by entering of the working oil into the space S2 on the rear surface 60b side of the spacer portion <NUM> from the first pilot chamber <NUM> through the screw fastening portion <NUM>, but the present invention is not limited to that. The present invention can be applied to various control valves in a form in which the pressure in the space S2 on the rear surface 60b side of the spacer portion <NUM> is raised when the pilot pressure is led to the first pilot chamber <NUM>.

The control valve <NUM> according to a second embodiment not part of the present invention will be described by referring to <FIG>. Differences from the aforementioned first embodiment will be mainly described below, and the same reference numerals are given to the same configurations as or the configuration corresponding to the configuration described in the first embodiment in the figures, and the description will be omitted.

The first embodiment describes the example in which the movement regulating portion <NUM> is configured to regulate the movement of the spacer portion <NUM> by the projecting portion 63a protruding outward in the radial direction of the spacer portion <NUM> and the taper portion 42c formed on the spool <NUM>.

As the movement regulating portion, various configurations can be employed which can regulate movement of the spacer portion <NUM> toward the poppet portion <NUM>.

In this second embodiment, as illustrated in <FIG>, a cylindrical elastic member <NUM> as the movement regulating portion is provided between the base end portion <NUM> of the spacer portion <NUM> and the large-diameter opening portion 42a of the second accommodating hole <NUM> in the control valve having the configuration similar to the comparative example (see <FIG>) of this embodiment.

The elastic member <NUM> is interposed between the base end portion <NUM> and the large-diameter opening portion 42a in a state compressed in the radial direction. The elastic member <NUM> can generate large sliding resistance as compared with the O-ring <NUM>, whereby the movement of the spacer portion <NUM> in the axial direction is regulated. A fitting recess portion fitted with the elastic member <NUM> may be further formed on the base end portion <NUM> of the spacer portion <NUM>.

The control valve <NUM> according to a third embodiment not part of the present invention will be described by referring to <FIG> and <FIG>. Differences from the aforementioned second embodiment will be mainly described below, and the same reference numerals are given to the same configurations as or the configuration corresponding to the configuration described in the second embodiment in the figures, and the description will be omitted.

In this third embodiment, a drain passage <NUM> is provided in order to prevent the pressure remaining in the space S2 on the rear surface 60b side of the spacer portion <NUM>, that is, on the rear surface side of the check valve <NUM>. The drain passage <NUM> is formed in the spool <NUM> and allows the communication groove <NUM> and the space S2 on the rear surface 60b side of the spacer portion <NUM> divided by the O-ring <NUM> to communicate with each other. One end of the drain passage <NUM> is opened in the inner peripheral surface of the third accommodating hole <NUM> and the other end of the drain passage <NUM> is opened in a bottom surface of the communication groove <NUM>.

Here, the force which regulates the movement of the spacer portion <NUM> might become smaller when the aforementioned elastic member <NUM> is deteriorated by use of the control valve <NUM> for a long time in some cases. In this case, when the pilot pressure is led to the first pilot chamber <NUM>, and the pressure in the space S2 on the rear surface 60b side of the spacer portion <NUM> is raised, the spacer portion <NUM> moves in the axial direction toward the poppet portion <NUM> in the closed valve state and presses the poppet portion <NUM> so as to press the poppet portion <NUM> onto the seat portion 41b as illustrated in <FIG>. Here, if the drain passage <NUM> is not provided, when the first pilot chamber <NUM> communicates with the tank after that, the pressure in the space S2 on the rear surface 60b side of the spacer portion <NUM> goes out to the tank through the screw fastening portion <NUM> of the one end portion of the spool <NUM> and the rod <NUM>. However, it takes time for the pressure in the space S2 on the rear surface 60b side of the spacer portion <NUM> to lower to the tank pressure. Thus, if the drain passage <NUM> is not provided, in the state (state where the pressure remains) where the pressure in the space S2 has not lowered to the tank pressure, when the pilot pressure is led to the second pilot chamber <NUM>, the valve opening operation of the poppet portion <NUM> according to the pressure of the second pilot chamber <NUM> is inhibited by the spacer portion <NUM>, and there is a concern that responsiveness of the check valve <NUM> is deteriorated.

On the other hand, in this third embodiment, since the drain passage <NUM> is formed, when the first pilot chamber <NUM> communicates with the tank from the state where the pilot pressure has been led to the first pilot chamber <NUM>, the space S2 on the rear surface 60b side of the spacer portion <NUM> communicates with the tank through the drain passage <NUM>, the communication groove <NUM>, and the first pilot chamber <NUM>. Passage resistance when the working oil passes through the drain passage <NUM> is smaller than the passage resistance when the working oil passes through the screw fastening portion <NUM>. Thus, when the first pilot chamber <NUM> communicates with the tank, the pressure quickly goes out to the tank from the space S2 through the drain passage <NUM>.

As described above, in this third embodiment, when the pilot pressure is led to the second pilot chamber <NUM>, and the first pilot chamber <NUM> communicates with the tank, the space S2 on the rear surface side of the check valve <NUM> divided by the O-ring <NUM> communicates with the tank through the drain passage <NUM>, the communication groove <NUM>, and the first pilot chamber <NUM>. Thus, when the pilot pressure is led to the second pilot chamber <NUM>, the pressure in the space S2 on the rear surface side of the check valve <NUM> divided by the O-ring <NUM> can be immediately lowered to the tank pressure. As a result, when the pilot pressure is led to the second pilot chamber <NUM>, the spacer portion <NUM> is moved to the left direction in the figure together with the poppet portion <NUM>, and the pilot pressure of the second pilot chamber <NUM> is immediately led to the other device through the signal pressure passage <NUM>. According to this third embodiment, even if the force of the elastic member <NUM> for regulating the movement of the spacer portion <NUM> becomes smaller, the responsiveness of the check valve <NUM> can be made favorable.

The number of the drain passages <NUM> may be one or may also be plural.

The aforementioned third embodiment describes the example in which the drain passage <NUM> allows the third accommodating hole <NUM> and the communication groove <NUM> to communicate with each other, but the drain passage <NUM> only needs to be configured to allow the space S2 on the rear surface 60b side of the spacer portion <NUM> and the communication groove <NUM> to communicate with each other. For example, the one end of the drain passage <NUM> may be opened in the inner peripheral surface of the second accommodating hole <NUM>.

The aforementioned third embodiment describes the example in which the cylindrical elastic member <NUM> is provided, but if the drain passage <NUM> is formed in the spool <NUM>, the elastic member <NUM> can be omitted. In this case, the poppet portion <NUM> and the spacer portion <NUM> constituting the check valve <NUM> do not have to be separate bodies. That is, the poppet portion <NUM> and the spacer portion <NUM> may be formed as an inseparable single component by bonding or integral molding. When the poppet portion <NUM> and the spacer portion <NUM> are integrally molded, the first internal passage <NUM> and the second internal passage <NUM> are formed from the rear surface side of the spacer portion <NUM>, and the opening portion thereof is closed by a plug or the like.

According to such configuration, when the pilot pressure is led to the first pilot chamber <NUM>, the pilot pressure of the first pilot chamber <NUM> is led to the space S2 through the screw fastening portion <NUM>, and even if the pressure in the space S2 rises higher than the tank pressure, when the pilot pressure is led to the second pilot chamber <NUM>, the pressure in the space S2 quickly goes out to the tank. Therefore, when the pilot pressure is led to the second pilot chamber <NUM>, the pressure in the space S2 on the rear surface side of the check valve <NUM> can be immediately lowered to the tank pressure. That is, according to this variation, occurrence of delay in the valve opening operation of the check valve <NUM> caused by the pressure remaining in the space S2 can be prevented, and the responsiveness of the check valve <NUM> can be improved.

The aforementioned third embodiment describes the example in which the pressure in the space S2 having been raised by the working oil entering into the space S2 on the rear surface 60b side of the spacer portion <NUM> from the first pilot chamber <NUM> through the screw fastening portion <NUM> is immediately made to escape to the tank when the first pilot chamber <NUM> communicates with the tank, but the present invention is not limited to that. The present invention can be applied to various control valves in a form in which the pressure in the space S2 on the rear surface 60b side of the spacer portion <NUM> is raised when the pilot pressure is led to the first pilot chamber <NUM>.

The configuration, actions, and effects of the embodiments of the present invention configured as above will be described collectively. The configuration in the parentheses is exemplification.

The control valve <NUM> includes the spool <NUM> slidably incorporated in the valve housing <NUM>, the first pilot chamber <NUM> and the second pilot chamber <NUM> disposed by facing the both ends of the spool <NUM>, the signal pressure passage <NUM> formed in the valve housing <NUM> and configured to lead the pilot pressure of the first pilot chamber <NUM> or the second pilot chamber <NUM> to the other device as a signal pressure, the communication groove <NUM> formed in the spool <NUM> and configured to allow the first pilot chamber <NUM> and the signal pressure passage <NUM> to communicate with each other when the spool <NUM> is at the neutral position, the communication hole <NUM> formed in the spool <NUM> and configured to allow the second pilot chamber <NUM> and the signal pressure passage <NUM> to communicate with each other, and the check valve <NUM> interposed in the communication hole <NUM> and configured to allow only the flow from the second pilot chamber <NUM> to the signal pressure passage <NUM>, in which the communication groove <NUM> allows the first pilot chamber <NUM> and the signal pressure passage <NUM> to communicate with each other when the pilot pressure is led to the first pilot chamber <NUM>, and the spool <NUM> is moved, while the communication between the first pilot chamber <NUM> and the signal pressure passage <NUM> is shut off when the pilot pressure is led to the second pilot chamber <NUM>, and the spool <NUM> is moved, the check valve <NUM> has the poppet portion <NUM> configured to open or close the communication hole <NUM> and the spacer portion <NUM> configured to regulate the movement amount of the poppet portion <NUM> to the open direction, and the control valve <NUM> further includes the movement regulating portion <NUM> configured to regulate movement of the spacer portion <NUM> toward the poppet portion <NUM>.

In this configuration, when the pilot pressure is led to the first pilot chamber <NUM>, even if the pilot pressure of the first pilot chamber <NUM> acts on the spacer portion <NUM> the movement of the spacer portion <NUM> toward the poppet portion <NUM> is regulated. As a result, since the gap is formed between the end surface of the spacer portion <NUM> and the poppet portion <NUM> in the closed valve state, when the pilot pressure is led to the second pilot chamber <NUM>, inhibition on the valve opening operation of the poppet portion <NUM> by the spacer portion <NUM> is prevented. As a result, the responsiveness of the check valve <NUM> can be improved.

In the control valve <NUM>, the check valve <NUM> is accommodated in the valve accommodating portion <NUM> opened in the one end surface of the spool <NUM>, the opening of the valve accommodating portion <NUM> is closed by the closing member (rod <NUM>) facing the inside of the first pilot chamber <NUM>, and the closing member (rod <NUM>) is screwed/fastened to the opening of the valve accommodating portion <NUM>.

In this configuration, the movement of the spacer portion <NUM> by the pilot pressure from the second pilot chamber <NUM> can be regulated by the closing member (rod <NUM>).

In the control valve <NUM>, the movement regulating portion <NUM> has the projecting portion 63a protruding outward in the radial direction of the spacer portion <NUM> and the abutting portion (taper portion 42c) provided in the spool <NUM> and configured to regulate the movement of the spacer portion <NUM> toward the poppet portion <NUM> by abutting to the projecting portion 63a.

In this configuration, the movement of the spacer portion <NUM> can be regulated only by providing the projecting portion 63a on the spacer portion <NUM> and providing the abutting portion (taper portion 42c) in the spool <NUM>, and thus, an increase in the manufacturing cost can be suppressed.

In the control valve <NUM>, the poppet portion <NUM> has the seated portion <NUM> capable of being seated on the seat portion 41b provided in the communication hole <NUM>, the first internal passage <NUM> opened in the end surface on the side opposite to the seated portion <NUM>, and the first through hole <NUM> opened in the outer peripheral surface and communicating with the first internal passage <NUM>, the spacer portion <NUM> has the second internal passage <NUM> opened in the end surface faced with the poppet portion <NUM> and the second through hole <NUM> opened in the outer peripheral surface and communicating with the second internal passage <NUM>, and the communication hole <NUM> has the communication path (second passage 20b) configured to allow the second through hole <NUM> of the spacer portion <NUM> and the signal pressure passage <NUM> of the valve housing <NUM> to communicate with each other.

In this configuration, the pilot pressure of the second pilot chamber <NUM> can be led to the signal pressure passage <NUM> through the first internal passage <NUM> of the poppet portion <NUM> and the second internal passage <NUM> of the spacer portion <NUM>.

Claim 1:
A control valve (<NUM>), comprising:
a spool (<NUM>) slidably incorporated in a valve housing (<NUM>);
a first pilot chamber (<NUM>) and a second pilot chamber (<NUM>) disposed by facing both ends of the spool (<NUM>);
a signal pressure passage (<NUM>) formed in the valve housing (<NUM>) and configured to lead a pilot pressure of the first pilot chamber (<NUM>) or the second pilot chamber (<NUM>) to another device other than the control valve (<NUM>) as a signal pressure;
a communication groove (<NUM>) formed in the spool (<NUM>) and configured to allow the first pilot chamber (<NUM>) and the signal pressure passage (<NUM>) to communicate with each other when the spool (<NUM>) is at a neutral position;
a communication hole (<NUM>) formed in the spool (<NUM>) and configured to allow the second pilot chamber (<NUM>) and the signal pressure passage (<NUM>) to communicate with each other; and
a check valve (<NUM>) interposed in the communication hole (<NUM>) and configured to allow only the flow from the second pilot chamber (<NUM>) to the signal pressure passage (<NUM>), wherein
the communication groove (<NUM>) allows the first pilot chamber (<NUM>) and the signal pressure passage (<NUM>) to communicate with each other when the pilot pressure is led to the first pilot chamber (<NUM>) and the spool (<NUM>) is moved, while the communication between the first pilot chamber (<NUM>) and the signal pressure passage (<NUM>) is shut off when the pilot pressure is led to the second pilot chamber (<NUM>) and the spool (<NUM>) is moved;
the check valve (<NUM>) comprises:
a poppet portion (<NUM>) configured to open or close the communication hole (<NUM>); and
a spacer portion (<NUM>) configured to regulate a movement amount of the poppet portion (<NUM>) to an open direction; and
the control valve (<NUM>) further comprises a movement regulating portion (<NUM>) configured to regulate movement of the spacer portion (<NUM>) toward the poppet portion (<NUM>);
characterized in that
in a state where the movement of the spacer portion (<NUM>) is regulated by the movement regulating portion (<NUM>) and the poppet portion (<NUM>) closes the communication hole (<NUM>), a gap is formed between the spacer portion (<NUM>) and the poppet portion (<NUM>).