Valve unit

Abstract

Reduce the pressure loss of the working fluid discharged into the tank while reducing the piping. 【Solution means】The valve unit 1 includes a housing 11, a first actuator port 11a and a second actuator port 11b that open to the outer surface of the housing 11 and are connected to the hydraulic motor 4, a tank port 11c that opens to the outer surface of the housing 11 and is connected to the tank T, a control valve 5 incorporated inside the housing 11 for controlling the operation of the hydraulic motor 4, and a quick return valve 7 incorporated inside the housing 11 for returning the hydraulic oil from the second actuator port 11b to the tank T through the tank port 11c without passing through the control valve 5. The tank port 11c opens to the outer surface of the housing 11 straddling a first section S1 where the control valve 5 is provided and a second section S2 where the quick return valve 7 is provided.

Description

Technical Field

[0001] The present invention relates to a valve unit.

Background Art

[0002] Patent Document 1 discloses a construction machine including a switching valve that can be switched between a first position where return oil from a hydraulic actuator is returned into a control valve and a second position where the return oil is directly returned to a tank. Patent Document 2 discloses a hydraulic cylinder circuit of a construction machine provided with a quick return valve that allows the flow of oil only during an arm pushing operation in a branch pipe that directly returns the return oil from the bottom side oil chamber to the tank during the arm pushing operation.

[0003] Patent Document 3 discloses a switching device for a hydraulic circuit of an excavator configured such that return oil from a breaker can be refluxed directly from a switching valve to a hydraulic oil tank. Patent Document 4 discloses a hydraulic circuit of an excavator in which a hydraulic switching valve is communicatively connected to a return path side of a hydraulic actuator, and one of the branches from the switching valve is communicatively connected directly to a hydraulic oil tank via a return oil pipe having a large inner diameter.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Patent Document 3

Patent Document 4

Summary of the Invention

Problems to be Solved by the Invention

[0005] If a quick return valve is provided between the actuator and the control valve by means of a pipe connection, pipes are required between the respective components, and pipes are also required between the quick return valve and the tank. On the other hand, rapid discharge of the working fluid is required for the quick return valve.

[0006] The present invention has been made in view of such problems, and an object thereof is to reduce the pressure loss of the working fluid discharged to the tank while reducing the piping.

Means for Solving the Problems

[0007] The present invention includes a housing, a first actuator port that opens to the outer surface of the housing and is connected to the actuator, a second actuator port that opens to the outer surface of the housing and is connected to the actuator, a tank port that opens to the outer surface of the housing and is connected to the tank, a control valve incorporated inside the housing for controlling the operation of the actuator, and a quick return valve incorporated inside the housing for returning the working fluid from the second actuator port to the tank through the tank port without passing through the control valve, and the tank port opens to the outer surface of the housing straddling a first section of the housing where the control valve is provided and a second section of the housing where the quick return valve is provided. It is a valve unit characterized by this.

[0008] According to the present invention, since the control valve and the quick return valve are provided in a single housing (monoblock), piping between the control valve and the quick return valve can be made unnecessary. In addition, since a tank port straddling both sections of the control valve and the quick return valve is provided, the tank port can be enlarged while achieving miniaturization of the housing, and the pressure loss of the working fluid discharged to the tank can be reduced.

[0009] Further, in the present invention, the first actuator port, the second actuator port, and the tank port are formed on a common surface of the housing. The first actuator port is provided in the first section, the second actuator port is provided in the second section, at least one of the first actuator port and the second actuator port is provided on one side in the longitudinal direction of the housing, and the tank port is provided on the other side in the longitudinal direction of the housing. This is a characteristic.

[0010] According to this invention, since a space can be secured on the other side in the longitudinal direction of the housing to provide the tank port, the size of the housing can be suppressed from increasing while the tank port can be enlarged.

[0011] Further, in the present invention, the first actuator port and the second actuator port are provided on one side in the longitudinal direction from the tank port, are formed in the housing, and further include a tank passage communicating with the tank port. The control valve includes a control spool, a supply port for the working fluid, and a first port provided on the other side in the longitudinal direction, which is blocked from the tank passage in a state of communicating with the supply port by the control spool and blocked from the supply port in a state of communicating with the tank passage. The quick return valve includes a quick return spool and a second port provided on the other side in the longitudinal direction, which is communicated with and blocked from the tank passage by the quick return spool. The housing has an internal flow path that connects a second actuator port provided on one side in the longitudinal direction from the tank port and a first port provided on the other side in the longitudinal direction through the second port. This is a characteristic.

[0012] According to the present invention, even when the tank port is provided on the other side in the longitudinal direction, and the first actuator port and the second actuator port are provided on one side in the longitudinal direction from the tank port, as described above, by providing an internal flow path extending from one side in the longitudinal direction from the tank port to the other side in the longitudinal direction, the second actuator port can be connected to the tank port through the quick return valve and the control valve. Further, since the first port communicates with and is blocked from the supply port, depending on the actuator applied, the second actuator port can also be used as a supply / discharge port for the working fluid.

[0013] The present invention further includes a signal pressure passage formed in the housing, provided across the quick return spool of the quick return valve, and communicated and blocked by the control spool of the control valve according to the switching position of the control valve. The quick return spool includes a signal pressure annular groove that communicates with the signal pressure passage regardless of the switching position of the quick return valve.

[0014] According to the present invention, even when the quick return spool is provided across the signal pressure passage, since the signal pressure annular groove of the quick return spool does not block the signal pressure passage, the switching position of the control valve can be detected. Therefore, it is not necessary to provide the quick return spool avoiding the signal pressure passage, and the layout property of the quick return spool and the signal pressure passage is improved.

Advantages of the Invention

[0015] According to these inventions, while reducing the piping, the pressure loss of the working fluid discharged to the tank can be reduced.

Brief Description of the Drawings

[0016]

Figure 1

Figure 2

Figure 3

Figure 4

Mode for Carrying Out the Invention

[0017] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

[0018] FIG. 1 is a schematic configuration diagram of the fluid pressure control device 100. FIG. 2 is a cross-section taken along the A-A line in FIG. 1, FIG. 3 is a cross-section taken along the B-B line in FIG. 1, and FIG. 4 is a cross-section taken along the C-C line in FIG. 3, each showing the valve unit 1.

[0019] The fluid pressure control device 100 shown in FIG. 1 includes a valve unit 1, a pump 3 which is a fluid pressure supply source for supplying hydraulic oil to the valve unit 1, and a tank T in which the hydraulic oil is stored. The valve unit 1 is mounted on a hydraulic excavator (for example, a backhoe), and controls the operation of a hydraulic motor 4 that drives a breaker (not shown) attached to the hydraulic excavator as an attachment. The hydraulic oil is a working fluid, and in addition to the hydraulic oil, an incompressible fluid such as water can be used as the working fluid. The valve unit 1 can also be used to control the operation of actuators such as hydraulic cylinders other than the hydraulic motor 4, and may be used in other construction machines.

[0020] The valve unit 1 has a housing 11. A valve housing 2 for controlling the operation of a hydraulic cylinder that drives a boom, an arm, a bucket, etc. of the hydraulic excavator is connected to the housing 11. These plurality of housings 2 and 11 constitute an integral valve block.

[0021] Hydraulic oil is supplied from the pump 3 into the valve block. The supplied hydraulic oil is supplied to each of the housings 2 and 11 through an oil passage formed in the valve block. The supply and discharge of the hydraulic oil to the corresponding hydraulic cylinder, hydraulic motor 4, etc. are controlled by each control valve incorporated in the housings 2 and 11.

[0022] The housing 11 is a single housing (monoblock) and has a first actuator port 11a, a second actuator port 11b, and a tank port 11c as openings that open to the outer surface of the housing 11. The first actuator port 11a is connected to the pressure oil supply port 4a of the hydraulic motor 4 through a pipe, and the second actuator port 11b is connected to the pressure oil discharge port 4b of the hydraulic motor 4 through a pipe.

[0023] The hydraulic oil guided into the valve unit 1 from the hydraulic motor 4 through the second actuator port 11b is discharged outside the valve unit 1 through the tank port 11c. The tank port 11c is connected to the tank T through a pipe, and the hydraulic oil is returned to the tank T through the tank port 11c. Note that the hydraulic oil can also be returned to the tank T from other than the tank port 11c from the valve block including the valve unit 1.

[0024] The housing 11 has a first section S1 and a second section S2. The first section S1 is a section where a control valve 5 (see FIGS. 2 and 4) described later is provided, and the first actuator port 11a is disposed in the first section S1. The second section S2 is a section where a quick return valve 7 (see FIGS. 3 and 4) described later is provided, and the second actuator port 11b is disposed in the second section S2. Thus, in the valve unit 1, two valves, i.e., the control valve 5 and the quick return valve 7, are incorporated in a single housing 11.

[0025] The first actuator port 11a and the second actuator port 11b are arranged side by side in the width direction of the housing 11, and the first section S1 and the second section S2 are defined so as to bisect the housing 11 in the width direction. The widths of the first and second sections S1 and S2 are set according to the outer diameters of the first and second actuator ports 11a and 11b, and are slightly larger than the outer diameters of the first and second actuator ports 11a and 11b. The boundary between the first section S1 and the second section S2 is located at the center (center in the width direction) between the spool valve 51 (see FIG. 4) of the control valve 5 described later and the spool valve 71 (see FIG. 4) of the quick return valve 7 described later. The first actuator port 11a, the second actuator port 11b, and the tank port 11c all open to the upper surface 11u (the surface on one side in the vertical direction; see FIG. 2), which is the outer surface of the housing 11. That is, the first actuator port 11a, the second actuator port 11b, and the tank port 11c are formed on a common surface of the housing 11.

[0026] In a breaker (not shown), the rotation of the hydraulic motor 4 is converted into the reciprocating motion of a bit (not shown) that crushes a paved road surface or the like. The bit is pushed back by the reaction force during crushing, and at this time, the flow rate discharged from the hydraulic motor 4 and returning to the tank T increases. Therefore, in order to realize smooth operation of the breaker, in the valve unit 1, in order to cope with a large return flow rate, it is desirable to quickly discharge the hydraulic oil from the hydraulic motor 4.

[0027] In the valve unit 1, the tank port 11c opens to the upper surface 11u of the housing 11 straddling the first section S1 and the second section S2. By providing the tank port 11c straddling both the first section S1 and the second section S2, it is possible to increase the tank port 11c while achieving miniaturization of the housing 11, and to reduce the pressure loss of the hydraulic oil discharged to the tank T. The tank port 11c is set larger than the second actuator port 11b, and the first actuator port 11a and the second actuator port 11b are set to be of the same size as each other.

[0028] The tank port 11c is arranged closer to the second section S2 in the width direction of the housing 11 and is provided so as to protrude from the second section S2 to the first section S1. By arranging the tank port 11c closer to the second section S2, the tank port 11c can be arranged closer to the second actuator port 11b than when the tank port 11c is arranged closer to the first section S1. Therefore, the distance between the second actuator port 11b and the tank port 11c can be shortened, and the pressure loss of the hydraulic oil guided from the second actuator port 11b to the tank port 11c can be reduced.

[0029] The first actuator port 11a and the second actuator port 11b have an installation portion A1 provided with a counterbore portion and an internal thread portion, and a joint (not shown) is assembled thereto, and the installation portion A1 opens to the upper surface 11u of the housing 11. The tank port 11c has an installation portion A2 provided with a counterbore portion and an internal thread portion, and a joint (not shown) is assembled thereto, and the installation portion A2 opens to the upper surface 11u of the housing 11.

[0030] On the upper surface 11u of the housing 11, which is a common surface, the first actuator port 11a and the second actuator port 11b are provided on one side in the longitudinal direction from the tank port 11c. The tank port 11c is provided on the other side (the lower side in FIG. 1) in the longitudinal direction of the housing 11. On the other hand, the first actuator port 11a and the second actuator port 11b are provided on one side (the upper side in FIG. 1) in the longitudinal direction (the lateral direction with respect to the vertical direction) of the housing 11. By providing the first actuator port 11a and the second actuator port 11b closer to one side in the longitudinal direction on the upper surface 11u of the housing 11, for example, when the first actuator port 11a is arranged along the longitudinal direction and the second actuator port 11b is arranged along the width direction with the tank port 11c, a installation space for the tank port 11c can be secured on the other side in the longitudinal direction. Therefore, while suppressing an increase in the size of the housing 11, the tank port 11c provided closer to the other side in the longitudinal direction can be enlarged.

[0031] The first actuator port 11a, the second actuator port 11b, and the tank port 11c may be opened on an outer surface other than the upper surface 11u of the housing 11, or may be opened on different surfaces from each other. Even in this case, by providing the tank port 11c that opens on the outer surface of the housing 11 across the first section S1 and the second section S2, the tank port 11c can be enlarged.

[0032] On the upper surface 11u of the housing 11, which is a common surface, only one of the first actuator port 11a and the second actuator port 11b may be provided on one side (the upper side in FIG. 1) in the longitudinal direction of the housing 11.

[0033] When the first actuator port 11a is provided on one side in the longitudinal direction, the second actuator port 11b adjacent to the tank port 11c can be provided on the other side in the longitudinal direction (the lower side in FIG. 1) or near the center in the longitudinal direction from one side in the longitudinal direction (the upper side in FIG. 1), and the size expansion of the housing 11 can be suppressed. Further, when the second actuator port 11b is provided on one side in the longitudinal direction, on the upper surface 11u of the housing 11, the first actuator port 11a adjacent to the tank port 11c obliquely (upper left in FIG. 1) can be provided on the other side in the longitudinal direction (the lower side in FIG. 1) or near the center in the longitudinal direction, and the first actuator port 11a is arranged along the longitudinal direction and the second actuator port 11b arranged along the width direction with the tank port 11c. Compared with the case where the second actuator port 11b is provided, the size expansion of the housing 11 can be suppressed as much as possible. The first actuator port 11a can be provided near the center in the longitudinal direction in the first section S1 by shifting the compensator valve 61 (see FIG. 2) described later.

[0034] In the valve unit 1, as an actuator, for example, a hydraulic cylinder may be connected instead of the hydraulic motor 4. In this case, both the first actuator port 11a and the second actuator port 11b constitute supply / discharge ports for supplying and discharging hydraulic oil to / from the hydraulic cylinder. When one supplies hydraulic oil to the hydraulic cylinder, the other discharges hydraulic oil from the hydraulic cylinder.

[0035] As shown in FIG. 2, the valve unit 1 has a control valve 5 incorporated inside the housing 11. The control valve 5 is a standby valve in the integrated valve block of the fluid pressure control device 100 and controls the operation of the hydraulic motor 4 (see FIG. 1) that drives a breaker attached to the hydraulic excavator as an attachment.

[0036] The control valve 5 includes a spool valve 51 as a control spool whose position is switched among a plurality of switching positions, and a housing hole 52 that slidably houses the spool valve 51. The control valve 5 has, as a plurality of switching positions, a neutral position where the spool valve 51 is in a neutral state (the state shown in FIG. 2), a first position where the spool valve 51 is located on the other side in the longitudinal direction (the right side in FIG. 2) compared to the neutral position, and a second position where the spool valve 51 is located on one side in the longitudinal direction (the left side in FIG. 2) compared to the neutral position. The first position is a supply position for supplying hydraulic oil to the hydraulic motor 4.

[0037] The spool valve 51 extends along the longitudinal direction of the housing 11. Therefore, it can be said that the longitudinal direction of the housing 11 is the direction in which the spool valve 51 extends. In the housing hole 52, an annular recess 53 provided in the center, a pump port 54 provided adjacent to the annular recess 53, supply ports 55, 56 provided outside the annular recess 53 and the pump port 54, working ports 57, 58 provided outside the supply ports 55, 56, discharge ports 81a, 81b provided outside the working ports 57, 58, and a first tank passage 81 communicating with the discharge ports 81a, 81b are formed. In the present embodiment, the discharge ports 81a, 81b are formed by the first tank passage 81.

[0038] The pump port 54 is connected to the pump 3 (see FIG. 1) through a pump passage 80 extending in the width direction of the housing 11 (the left - right direction in FIG. 1). The hydraulic oil discharged from the pump 3 is constantly guided to the pump port 54.

[0039] The first tank passage 81 is formed in the first section S1 of the housing 11 (see FIGS. 1 and 4). The discharge port 81a is provided on one side in the longitudinal direction (the left side in FIG. 2) adjacent to the working port 57, and the discharge port 81b is provided on the other side in the longitudinal direction (the right side in FIG. 2) adjacent to the working port 58.

[0040] The first tank passage 81 extends in a direction away from the spool valve 51 from the discharge ports 81a and 81b (the lower side in FIG. 2), and then extends toward the inside of the housing 11 substantially parallel to the spool valve 51 and connects to each other. The fourth tank passage 84 and the fifth tank passage 85 that extend in the width direction (see FIG. 1) communicate with the first tank passage 81, and the first tank passage 81 is connected to the tank T (see FIG. 1) through the fourth tank passage 84 and the fifth tank passage 85. The fourth tank passage 84 and the fifth tank passage 85 are formed in the housing 11 as part of a common tank passage for a plurality of control valves and the like arranged side by side in the width direction in the integral valve block of the fluid pressure control device 100 (see FIG. 1). In addition, a second tank passage 82 (see FIG. 3) and a third tank passage 83 (see FIG. 4) described later are also formed in the housing 11. The first to fifth tank passages 81 to 85 correspond to tank passages.

[0041] A first internal flow path 91 that communicates the operation port 57 and the first actuator port 11a is formed in the housing 11. The first internal flow path 91 is arranged on one side in the longitudinal direction together with the first actuator port 11a and the operation port 57. The first actuator port 11a and the operation port 57 overlap in the longitudinal direction view (the vertical direction view in FIG. 2), and the first internal flow path 91 extends substantially vertically (the upper side in FIG. 2) from the operation port 57 and connects to the first actuator port 11a. Therefore, the operation port 57 is connected to the pressure oil supply port 4a (see FIG. 1) of the hydraulic motor 4 through the first internal flow path 91 and the first actuator port 11a.

[0042] In the state where the spool valve 51 is in the neutral position shown in FIG. 2, a first annular groove 51a formed at a position facing the pump port 54, a second annular groove 51b formed at a position facing the annular recess 53, a third annular groove 51c formed at a position facing the working port 57, a fourth annular groove 51d formed at a position facing the working port 58, and a fifth annular groove 51e formed at a position facing a signal pressure passage P described later are provided. At one end of the spool valve 51, a first pilot chamber 21 and a centering spring 22 are provided, and at the other end of the spool valve 51, a second pilot chamber 23 and a centering spring 24 are provided. Pilot pressure is supplied to the first pilot chamber 21 through a first solenoid 62, and pilot pressure is supplied to the second pilot chamber 23 through a second solenoid 63. In the neutral position, the working ports 57 and 58 are blocked from the supply ports 55 and 56 and the discharge ports 81a and 81b by the spool valve 51.

[0043] The control valve 5 further has a valve housing hole 60 formed orthogonal to the housing hole 52 and a compensator valve 61 slidably housed in the valve housing hole 60. The annular recess 53 and the supply ports 55 and 56 communicate with each other through the compensator valve 61, and the opening degree for this communication changes according to the pressure of the hydraulic oil acting on the compensator valve 61.

[0044] When pilot pressure is introduced into the first pilot chamber 21 and the spool valve 51 moves to the other side (the right side in FIG. 2) in the longitudinal direction to reach the first position, the pump port 54 and the annular recess 53 communicate with each other through the first annular groove 51a and a notch (not shown) communicating with the first annular groove 51a, and hydraulic oil is introduced into the supply ports 55 and 56. The hydraulic oil introduced into the supply port 55 passes through the working port 57 communicating with the supply port 55 through the third annular groove 51c, and is supplied to the pressure oil supply port 4a of the hydraulic motor 4 (see FIG. 1) through the first internal flow path 91 and the first actuator port 11a. The hydraulic oil supplied to the hydraulic motor 4 is then led from the pressure oil discharge port 4b of the hydraulic motor 4 to the second actuator port 11b (see FIGS. 1 and 3).

[0045] As shown in FIG. 3, the valve unit 1 has a quick return valve 7. The quick return valve 7 is incorporated inside the housing 11 and is arranged side by side with the control valve 5 in the width direction of the housing 11 (see FIG. 4). Therefore, the width direction can also be said to be the direction in which the control valve 5 and the quick return valve 7 are arranged side by side.

[0046] The quick return valve 7 has a spool valve 71 as a quick return spool whose position is switched between a plurality of switching positions, and a housing hole 72 that slidably houses the spool valve 71. The quick return valve 7 has two switching positions as a plurality of switching positions, a neutral position where the spool valve 71 is in a neutral state (the state shown in FIG. 3), and a discharge position where the spool valve 71 is located on one side (the left side in FIG. 3) in the longitudinal direction compared to the neutral position. The spool valve 71 extends along the longitudinal direction of the housing 11 in the same manner as the spool valve 51.

[0047] The housing hole 72 is formed with a first connection port 73, a second connection port 74 adjacent to the first connection port 73 from one side (the left side in FIG. 3) in the longitudinal direction, a discharge port 82a adjacent to the first connection port 73 from the other side (the right side in FIG. 3) in the longitudinal direction, and a second tank passage 82 communicating with the discharge port 82a. In the present embodiment, the discharge port 82a is formed by the second tank passage 82. The first connection port 73, the second connection port 74, and the discharge port 82a are all provided on the other side (the right side in FIG. 3) in the longitudinal direction.

[0048] The second tank passage 82 is formed in the second section S2 of the housing 11 (see FIGS. 1 and 4). The discharge port 82a overlaps the tank port 11c in a vertical view (in the vertical direction in FIG. 3), and the second tank passage 82 extends substantially vertically (upward in FIG. 3) from the discharge port 82a and communicates with the tank port 11c.

[0049] The second tank passage 82 extends from the discharge port 82a in a direction away from the spool valve 71 (the lower side in FIG. 3), then extends toward one side in the longitudinal direction (the left side in FIG. 3) substantially parallel to the spool valve 71, and further extends toward the spool valve 71 substantially perpendicular to the spool valve 71 (the upper side in FIG. 3), passes around the spool valve 71, and then is connected to a tank port 11d that opens to one side surface of the housing 11 (the left side surface in FIG. 3). The tank port 11d will be described later.

[0050] The fourth tank passage 84 and the fifth tank passage 85 communicate with the second tank passage 82, and the second tank passage 82 is connected to the tank T (see FIG. 1) through the fourth tank passage 84 and the fifth tank passage 85. That is, similar to the control valve 5, the quick return valve 7 is also connected to a common tank passage formed in the fluid pressure control device 100 (see FIG. 1). For this reason, the second tank passage 82 also communicates with the first tank passage 81 through the fourth tank passage 84 and the fifth tank passage 85.

[0051] A second internal passage 92 (see FIGS. 3 and 4) that communicates the second actuator port 11b with the operating port 58 of the control valve 5 (see FIG. 2) is formed in the housing 11. The second internal passage 92 connects the second actuator port 11b and the operating port 58 of the control valve 5 through the first connection port 73 of the quick return valve 7.

[0052] In a state where the spool valve 71 is in the neutral position shown in FIG. 3, the spool valve 71 has a first annular groove 71a formed at a position facing the discharge port 82a, a second annular groove 71b that communicates the first connection port 73 and the second connection port 74, and a third annular groove 71c formed at a position facing the signal pressure passage P. A centering spring 25 is provided at one end of the spool valve 71 (the left side in FIG. 3), and a pilot chamber 26 is provided at the other end of the spool valve 71 (the right side in FIG. 3). Pilot pressure is supplied to the pilot chamber 26 through the solenoid 64.

[0053] When the pilot pressure is introduced into the pilot chamber 26 and the spool valve 71 moves to one side in the longitudinal direction (the left side in FIG. 3) to reach the discharge position, the first connection port 73 and the discharge port 82a communicate with each other through the first annular groove 71a, and the first connection port 73 and the second connection port 74 are blocked. Therefore, when the quick return valve 7 is in the discharge position, the hydraulic oil guided from the hydraulic motor 4 (see FIG. 1) to the second internal flow path 92 through the second actuator port 11b is discharged from the tank port 11c through the first connection port 73 and the second tank passage 82.

[0054] In this way, the quick return valve 7 can return the hydraulic oil from the second actuator port 11b to the tank T (see FIG. 1) through the tank port 11c without passing through the control valve 5, thereby reducing the pressure loss. The first connection port 73 corresponds to the second port and communicates with and is blocked from the discharge port 82a by the spool valve 71.

[0055] The switching position of the quick return valve 7 can be switched by a switching operation by a user using an operation unit such as a switch. The switching of the quick return valve 7 may be interlocked with, for example, the switching operation of the control valve 5. In response to the switching of the control valve 5 from the neutral position to the first position, by switching the quick return valve 7 from the neutral position to the discharge position, when the control valve 5 supplies hydraulic oil to the hydraulic motor 4 through the first actuator port 11a, the hydraulic oil can be discharged from the tank port 11c through the quick return valve 7. Also, in response to the switching of the control valve 5 from the first position to the neutral position, by switching the quick return valve 7 from the discharge position to the neutral position, when the control valve 5 stops supplying the hydraulic oil, the quick return valve 7 can be returned to the neutral position.

[0056] The second internal flow path 92 has a first partial flow path 92a connecting the second actuator port 11b and the first connection port 73, and a second partial flow path 92b (see FIG. 4) connecting the second connection port 74 of the quick return valve 7 and the working port 58 of the control valve 5.

[0057] The first partial flow path 92a extends from the second actuator port 11b toward the spool valve 71, then extends substantially parallel to the spool valve 71, and further extends toward the spool valve 71 and connects to the first connection port 73. The first partial flow path 92a overlaps the spool valve 71 in a vertical direction view (viewed in the vertical direction in FIG. 3).

[0058] As shown in FIG. 4, the second partial flow path 92b extends from the second connection port 74 toward the operating port 58 while being inclined with respect to the spool valve 71 (diagonally downward in FIG. 4) and connects to the operating port 58. The second partial flow path 92b overlaps the spool valve 51 of the control valve 5 and the spool valve 71 of the quick return valve 7 in a width direction view (viewed in the vertical direction in FIG. 4).

[0059] When the quick return valve 7 is in the neutral position shown in FIG. 3, the spool valve 71 causes the first connection port 73 and the second connection port 74 to communicate with each other through the second annular groove 71b, and the first connection port 73 and the discharge port 82a are blocked. Therefore, when the switching position of the quick return valve 7 is in the neutral position, the hydraulic oil from the second actuator port 11b is guided to the operating port 58 of the control valve 5 through the second internal flow path 92. Further, when the control valve 5 shown in FIG. 2 is in the first position where the spool valve 51 has moved to the other side in the longitudinal direction (the right side in FIG. 2), the operating port 58 and the discharge port 81b communicate with each other through the fourth annular groove 51d.

[0060] For this reason, when the switching position of the quick return valve 7 is in the neutral position, the hydraulic oil from the second actuator port 11b can also be returned to the tank T (see FIG. 1) through the control valve 5. Thereby, an option of not using the quick return valve 7 can also be provided.

[0061] The working port 58 is communicated with and blocked from the discharge port 81b of the first tank passage 81 by the spool valve 51, blocked from the supply port 56 of the hydraulic oil in a state of being communicated with the discharge port 81b of the first tank passage 81, and blocked from the discharge port 81b of the first tank passage 81 in a state of being communicated with the supply port 56. Therefore, the second actuator port 11b communicating with the working port 58 through the second internal flow path 92 can also function as a supply / discharge port. The working port 58 corresponds to the first port.

[0062] As shown in FIG. 4, the discharge port 81b of the first tank passage 81 and the discharge port 82a of the second tank passage 82 communicate with each other through the third tank passage 83. For this reason, when discharging the hydraulic oil from the control valve 5 through the discharge port 81b of the first tank passage 81, the hydraulic oil can be easily discharged from the tank port 11c through the third tank passage 83. Thereby, the control valve 5 can also reduce the pressure loss by using the tank port 11c.

[0063] The discharge port 82a of the second tank passage 82 is set to have a larger dimension (the dimension in the left-right direction in FIG. 4) along the longitudinal direction than the discharge port 81b of the first tank passage 81. Thereby, compared with the case of discharging the hydraulic oil through the discharge port 81b of the first tank passage 81, the pressure loss when discharging the hydraulic oil through the discharge port 82a of the second tank passage 82 can be reduced.

[0064] Since the tank port 11d shown in FIG. 3 is provided on one side in the longitudinal direction, the hydraulic oil close to the tank port 11d can be quickly discharged compared to the tank port 11c provided on the other side in the longitudinal direction. On the other hand, for the quick return valve 7, in order to cope with a large flow rate returned from the hydraulic motor 4, a quick discharge of the hydraulic oil is required. The hydraulic oil discharged through the discharge port 82a of the second tank passage 82 is mainly discharged from the tank port 11c provided on the other side in the longitudinal direction together with the discharge port 82a. Since the cross-sectional area of the tank port 11c is set larger than that of the tank port 11d, the pressure loss of the hydraulic oil discharged through the tank port 11c is reduced compared to the case where the hydraulic oil is discharged through the tank port 11d or the case where a tank port of the same size as the tank port 11d is provided instead of the tank port 11c.

[0065] When, for example, a hydraulic cylinder is applied as an actuator instead of the hydraulic motor 4 (see FIG. 1), when the control valve 5 is set to the first position with the quick return valve 7 in the neutral position, the first actuator port 11a functions as a supply port for the hydraulic oil to the hydraulic cylinder, and the second actuator port 11b functions as a discharge port for the hydraulic oil from the hydraulic cylinder. Therefore, also in this case, the hydraulic oil from the second actuator port 11b is discharged through the discharge port 81b of the first tank passage 81. Further, in this case, if the quick return valve 7 is switched to the discharge position, the hydraulic oil discharged from the hydraulic cylinder can also be discharged from the tank port 11c through the quick return valve 7.

[0066] When a hydraulic cylinder is applied as an actuator, when the control valve 5 is set to the second position with the quick return valve 7 in the neutral position, the first actuator port 11a functions as a discharge port, and the second actuator port 11b functions as a supply port. In the second position, the hydraulic oil is controlled as follows.

[0067] That is, when the pilot pressure is introduced into the second pilot chamber 23 and the spool valve 51 moves to the second position on one side in the longitudinal direction (the left side in FIG. 2), the pump port 54 and the annular recess 53 communicate with each other through the second annular groove 51b and a notch (not shown) communicating with the second annular groove 51b, and the hydraulic oil is introduced into the supply ports 55 and 56. The hydraulic oil introduced into the supply port 56 passes through the working port 58 communicating with the supply port 56 through the fourth annular groove 51d, and is supplied to the hydraulic cylinder through the second partial flow path 92b, the second connection port 74, the first connection port 73, the first partial flow path 92a, and the second actuator port 11b (see FIGS. 3 and 4). Further, the hydraulic oil is introduced from the hydraulic cylinder into the first actuator port 11a, and is guided to the first tank passage 81 through the first internal flow path 91, the working port 57, and the third annular groove 51c.

[0068] Relief valves (not shown) can be provided on both side surfaces (the left and right side surfaces in FIG. 2) of the housing 11. The relief valve provided on the left side surface in FIG. 2 opens when the hydraulic pressure in the first internal flow path 91 is equal to or higher than the set pressure, and can communicate the first internal flow path 91 with the first tank passage 81 extending in the direction away from the spool valve 51 from the discharge port 81a (the upper side in FIG. 2). Further, the relief valve provided on the right side surface in FIG. 2 opens when the hydraulic pressure in the third internal flow path 93 extending substantially vertically (the upper side in FIG. 2) from the working port 58 is equal to or higher than the set pressure, and can communicate the third internal flow path 93 with the first tank passage 81 extending in the direction away from the spool valve 51 from the discharge port 81b (the upper side in FIG. 2).

[0069] As shown in Fig. 4, the valve unit 1 is formed in the housing 11, provided across the spool valve 71 of the quick return valve 7, and further includes a signal pressure passage P that is communicated and blocked by the spool valve 51 of the control valve 5 according to the switching position of the control valve 5. The signal pressure passage P extends along the width direction and opens to one end surface (the lower surface in Fig. 4) and the other end surface (the upper surface in Fig. 4) of the housing 11. The signal pressure passage P is provided for detecting the neutral position of the control valve 5. When the control valve 5 and the quick return valve 7 are in the neutral positions shown in Fig. 4, they are in a communicating state through the fifth annular groove 51e of the control valve 5 and the third annular groove 71c of the quick return valve 7. When the control valve 5 is switched from the neutral position to the first position or the second position, it is blocked by the spool valve 51.

[0070] The signal pressure passage P has a first partial passage P1 that communicates with the fifth annular groove 51e without crossing the spool valve 71, and a second partial passage P2 that crosses the spool valve 71 and communicates with the fifth annular groove 51e. The first partial passage P1 communicates with the fifth annular groove 51e from the side opposite to the quick return valve 7 side (the lower side in Fig. 4), and the second partial passage P2 communicates with the fifth annular groove 51e from the quick return valve 7 side (the upper side in Fig. 4).

[0071] The first partial passage P1 and the second partial passage P2 communicate with the fifth annular groove 51e in a state of being offset from the center of the fifth annular groove 51e in opposite directions in the longitudinal direction when the control valve 5 is in the neutral position. The first partial passage P1 is offset to the left side in Fig. 4 from the center of the fifth annular groove 51e, and the second partial passage P2 is offset to the right side in Fig. 4 from the center of the fifth annular groove 51e. The first partial passage P1 is provided between the annular recess 53 and the supply port 56 in the longitudinal direction, and the second partial passage P2 is provided adjacent to the second connection port 74 from one side in the longitudinal direction.

[0072] When the spool valve 51 moves to the left side in FIG. 4, the upper second partial passage P2 in FIG. 4 is blocked from the fifth annular groove 51e by the spool valve 71 prior to the lower first partial passage P1 in FIG. 4. When the spool valve 51 moves to the right side in FIG. 4, the lower first partial passage P1 in FIG. 4 is blocked from the fifth annular groove 51e by the spool valve 71 prior to the upper second partial passage P2 in FIG. 4. Therefore, the movement amount of the spool valve 51 that blocks the signal pressure passage P can be made uniform when moving to one side and the other side in the longitudinal direction from the neutral position.

[0073] The third annular groove 71c of the spool valve 71 is a signal pressure annular groove, and the groove width of the third annular groove 71c (the width in the left-right direction in FIG. 4) is set to a size that maintains the second partial passage P2 in a communicating state both when the spool valve 71 is in the neutral position and when it is in the discharge position. That is, the third annular groove 71c communicates with the signal pressure passage P regardless of the switching position of the quick return valve 7. Thereby, even if the spool valve 71 is provided so as to cross the signal pressure passage P, the switching position of the control valve 5 can be detected, so that it is not necessary to provide the spool valve 71 avoiding the signal pressure passage P, and the layout property of the spool valve 71 and the signal pressure passage P is improved.

[0074] Hereinafter, the configuration, operation, and effects of the embodiments of the present invention will be collectively described.

[0075] The valve unit 1 includes a housing 11, a first actuator port 11a that opens to the outer surface of the housing 11 and is connected to a hydraulic motor 4 which is an example of an actuator, a second actuator port 11b that opens to the outer surface of the housing 11 and is connected to the hydraulic motor 4, a tank port 11c that opens to the outer surface of the housing 11 and is connected to a tank T, a control valve 5 incorporated inside the housing 11 for controlling the operation of the hydraulic motor 4, and a quick return valve 7 incorporated inside the housing 11 for returning the hydraulic oil from the second actuator port 11b to the tank T through the tank port 11c without passing through the control valve 5. The tank port 11c opens to the outer surface of the housing 11 straddling a first section S1 of the housing 11 where the control valve 5 is provided and a second section S2 of the housing 11 where the quick return valve 7 is provided.

[0076] According to this configuration, since the control valve 5 and the quick return valve 7 are provided in the housing 11 which is a single housing (monoblock), piping between the control valve 5 and the quick return valve 7 can be made unnecessary. Also, since the tank port 11c straddling both sections of the control valve 5 and the quick return valve 7 is provided, while achieving miniaturization of the housing 11, the tank port 11c can be enlarged, and the pressure loss of the working fluid discharged to the tank T can be reduced.

[0077] The first actuator port 11a, the second actuator port 11b, and the tank port 11c are formed on the upper surface 11u which is a common surface of the housing 11. The first actuator port 11a is provided in the first section S1, and the second actuator port 11b is provided in the second section S2. The first actuator port 11a and the second actuator port 11b are provided on one side in the longitudinal direction of the housing 11, and the tank port 11c is provided on the other side in the longitudinal direction of the housing 11. At least one of the first actuator port 11a and the second actuator port 11b may be provided on one side in the longitudinal direction of the housing 11.

[0078] According to this configuration, since a space can be secured on the other side in the longitudinal direction of the housing 11 to provide the tank port 11c, the size of the housing 11 can be suppressed from increasing while the tank port 11c can be enlarged.

[0079] The first actuator port 11a and the second actuator port 11b are provided on one side in the longitudinal direction of the housing 11 rather than the tank port 11c. The valve unit 1 further includes first to fifth tank passages 81 to 85 that are tank passages formed in the housing 11 and communicate with the tank port 11c. The control valve 5 includes a spool valve 51 that is a control spool, a supply port 56 for hydraulic oil, and an operation port 58 (first port) provided on the other side in the longitudinal direction, which is blocked from communicating with the first tank passage 81 in a state of communicating with the supply port 56 by the spool valve 51 and is blocked from communicating with the supply port 56 in a state of communicating with the first tank passage 81. The quick return valve 7 includes a spool valve 71 that is a quick return spool and a first connection port 73 (second port) provided on the other side in the longitudinal direction, which is communicated with and blocked from the second tank passage 82 by the spool valve 71. The housing 11 has a second internal flow path 92 that connects the second actuator port 11b provided on one side in the longitudinal direction rather than the tank port 11c and the operation port 58 provided on the other side through the first connection port 73.

[0080] According to this configuration, even when the tank port 11c is provided on the other side in the longitudinal direction, and the first actuator port 11a and the second actuator port 11b are provided on one side in the longitudinal direction from the tank port 11c, as described above, by providing the second internal flow path 92 extending from one side in the longitudinal direction from the tank port 11c to the other side in the longitudinal direction, the second actuator port 11b can be connected to the tank port 11c through the quick return valve 7 and the control valve 5. Further, since the working port 58 communicates with and is blocked from the supply port 56, depending on the actuator to which it is applied, the second actuator port 11b can also be used as a supply / discharge port for the hydraulic oil.

[0081] The valve unit 1 is formed in the housing 11, provided across the spool valve 71, and further includes a signal pressure passage P that is communicated with and blocked by the spool valve 51 according to the switching position of the control valve 5. The spool valve 71 includes a third annular groove 71c as a signal pressure annular groove that communicates with the signal pressure passage P regardless of the switching position of the quick return valve 7.

[0082] According to this configuration, even when the spool valve 71 is provided so as to cross the signal pressure passage P, since the third annular groove 71c of the spool valve 71 does not block the signal pressure passage P, the switching position of the control valve 5 can be detected. Therefore, it is not necessary to provide the spool valve 71 avoiding the signal pressure passage P, and the layout property of the spool valve 71 and the signal pressure passage P is improved.

Description of Reference Numerals

[0083] 1 ··· Valve unit, 4 ··· Hydraulic motor (actuator), 5 ··· Control valve, 7 ··· Quick return valve, 11 ··· Housing, 11a ··· First actuator port, 11b ··· Second actuator port, 11c ··· Tank port, 51 ··· Spool valve (control spool), 56 ··· Supply port, 58 ··· Actuating port (first port), 71 ··· Spool valve (quick return spool), 71c ··· Third annular groove (signal pressure annular groove), 73 ··· First connection port (second port), 81 - 85 ··· First to fifth tank passages (tank passages), 92 ··· Second internal flow path (internal flow path), 100 ··· Fluid pressure control device, P ··· Signal pressure passage, S1 ··· First section, S2 ··· Second section, T ··· Tank

Claims

1. A housing, A first actuator port that opens to the outer surface of the housing and is connected to an actuator, A second actuator port that opens to the outer surface of the housing and is connected to the actuator, A tank port that opens to the outer surface of the housing and is connected to a tank, A control valve incorporated inside the housing for controlling the operation of the actuator, A quick return valve incorporated inside the housing for returning the working fluid from the second actuator port to the tank through the tank port without passing through the control valve, and the tank port opens to the outer surface of the housing straddling a first section of the housing where the control valve is provided and a second section of the housing where the quick return valve is provided. A valve unit characterized by the above.

2. The valve unit according to claim 1, wherein the first actuator port, the second actuator port, and the tank port are formed on a common surface of the housing, the first actuator port is provided in the first section, the second actuator port is provided in the second section, at least one of the first actuator port and the second actuator port is provided on one side in the longitudinal direction of the housing, and the tank port is provided on the other side in the longitudinal direction of the housing. A valve unit characterized by the above.

3. The valve unit according to claim 2, wherein the first actuator port and the second actuator port are provided on one side in the longitudinal direction from the tank port. It further includes a tank passage formed in the housing and communicating with the tank port. The control valve includes a control spool, a supply port for the working fluid, and a first port provided on the other side in the longitudinal direction, which is blocked from the tank passage in a state of communicating with the supply port by the control spool and blocked from the supply port in a state of communicating with the tank passage. The quick return valve includes a quick return spool, and a second port provided on the other side in the longitudinal direction, which is communicated with and blocked from the tank passage by the quick return spool. The housing has an internal flow path that connects the second actuator port provided on one side in the longitudinal direction from the tank port and the first port provided on the other side in the longitudinal direction through the second port. A valve unit characterized by the above.

4. The valve unit according to claim 1, further includes a signal pressure passage formed in the housing, provided across the quick return spool of the quick return valve, and communicated with and blocked by the control spool of the control valve according to the switching position of the control valve. The quick return spool includes a signal pressure annular groove that communicates with the signal pressure passage regardless of the switching position of the quick return valve. A valve unit characterized by the above.

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