Valve unit

Abstract

A valve unit 1 comprises: a housing 11; a first actuator port 11a and a second actuator port 11b that open in an outer surface of the housing 11 and are connected to a hydraulic motor 4; a tank port 11c that opens in the outer surface of the housing 11 and is connected to a tank T; a control valve 5 that is built into the interior of the housing 11 and controls the operation of the hydraulic motor 4; and a quick return valve 7 that is built into the interior of the housing 11 and returns a hydraulic fluid from the second actuator port 11b to the tank T through the tank port 11c without the hydraulic fluid passing through the control valve 5. The tank port 11c opens in the outer surface of the housing 11, spanning between 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

Valve Unit

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

[0002] JP2014-9572A discloses a construction machine equipped with a switching valve that can be switched between a first position that returns return oil from a hydraulic actuator into a control valve and a second position that returns the return oil directly to a tank.JP2013-137062A discloses a hydraulic cylinder circuit for a construction machine that is provided with a quick return valve in a branch pipe that returns return oil from a bottom-side oil chamber directly to a tank during arm pushing operations, and that allows oil to flow only during arm pushing operations.

[0003] JPS62-169053U discloses a switching device for a hydraulic circuit of a backhoe that is configured so that return oil from a breaker can be returned directly to a hydraulic oil tank from a switching valve.JPS61-84754U discloses a hydraulic circuit of a backhoe in which a hydraulic switching valve is connected in communication with the return side of a hydraulic actuator, and one branch from the switching valve is connected in communication with a hydraulic oil tank directly via a large-diameter return oil pipe.

[0004] If a quick return valve is provided by piping between the actuator and the control valve, piping is required between each component, as well as between the quick return valve and the tank. On the other hand, the quick return valve is required to quickly discharge the working fluid.

[0005] The present invention has been made in view of the above problems, and has an object to reduce the pressure loss of the working fluid discharged into the tank while reducing the amount of piping.

[0006] According to one aspect of the present invention, there is provided a valve unit comprising: a housing; a first actuator port that opens onto an outer surface of the housing and is connected to an actuator; a second actuator port that opens onto the outer surface of the housing and is connected to a tank; a control valve that is incorporated inside the housing and controls the operation of the actuator; and a quick return valve that is incorporated inside the housing and returns working fluid from the second actuator port to the tank through the tank port without passing through the control valve, wherein the tank port opens onto the outer surface of the housing, spanning a first section of the housing in which the control valve is provided and a second section of the housing in which the quick return valve is provided.

[0007] Fig. 1 is a schematic configuration diagram of a fluid pressure control device according to an embodiment of the present invention. Fig. 2 is a cross-sectional view of the valve unit taken along line A-A in Fig. 1. Fig. 3 is a cross-sectional view of the valve unit taken along line B-B in Fig. 1. Fig. 4 is a cross-sectional view of the valve unit taken along line CC in Fig. 3.

[0008] Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings.

[0009] Fig. 1 is a schematic diagram of a fluid pressure control device 100. Fig. 2 is a cross-sectional view taken along line AA in Fig. 1, Fig. 3 is a cross-sectional view taken along line BB in Fig. 1, and Fig. 4 is a cross-sectional view taken along line CC in Fig. 3, showing the valve unit 1.

[0010] 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 that supplies 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 (e.g., a backhoe) and controls the operation of a hydraulic motor 4 which drives a breaker (not shown) attached to the hydraulic excavator as an attachment. The hydraulic oil is a working fluid, and in addition to 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 other than the hydraulic motor 4, such as hydraulic cylinders, and may be used in other construction machinery.

[0011] The valve unit 1 has a housing 11. Connected to the housing 11 are housings 2 for valves that control the operation of hydraulic cylinders that drive the boom, arm, bucket, etc. of the hydraulic excavator. These multiple housings 2, 11 form an integrated valve block.

[0012] Hydraulic oil is supplied into the valve block from a pump 3. The supplied hydraulic oil is then supplied to each of the housings 2, 11 through oil passages formed in the valve block. The supply and discharge of hydraulic oil to the corresponding hydraulic cylinders, hydraulic motors 4, etc. is controlled by each control valve incorporated in the housings 2, 11.

[0013] 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 a pressure oil supply port 4a of the hydraulic motor 4 via piping, and the second actuator port 11b is connected to a pressure oil discharge port 4b of the hydraulic motor 4 via piping.

[0014] The hydraulic oil introduced into the valve unit 1 from the hydraulic motor 4 through the second actuator port 11b is discharged to the outside of the valve unit 1 through the tank port 11c. The tank port 11c is connected to a tank T via piping, 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 the valve block including the valve unit 1 through a port other than the tank port 11c.

[0015] The housing 11 has a first section S1 and a second section S2. The first section S1 is a section in which a control valve 5 (see FIGS. 2 and 4) described later is provided, and a first actuator port 11a is arranged in the first section S1. The second section S2 is a section in which a quick return valve 7 (see FIGS. 3 and 4) described later is provided, and a second actuator port 11b is arranged in the second section S2. In this way, the valve unit 1 incorporates two valves, the control valve 5 and the quick return valve 7, in a single housing 11.

[0016] 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 to divide the housing 11 in half in the width direction. The widths of the first and second sections S1 and S2 are set to match 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 (widthwise center) between a spool valve 51 (see FIG. 4) of the control valve 5 (described later) and a 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 top surface 11u (one side surface in the vertical direction; see FIG. 2), which is the outer surface of the housing 11. That is, the first actuator port 11 a, the second actuator port 11 b, and the tank port 11 c are formed on a common surface of the housing 11 .

[0017] In a breaker (not shown), the rotation of the hydraulic motor 4 is converted into the reciprocating motion of a bit (not shown) that breaks up pavement and other surfaces. The bit is pushed back by a reaction force when breaking up, and at this time, the flow rate discharged from the hydraulic motor 4 and returned to the tank T increases. For this reason, in order to achieve smooth operation of the breaker, it is desirable for the valve unit 1 to quickly discharge hydraulic oil from the hydraulic motor 4 in order to handle the large return flow rate.

[0018] In the valve unit 1, the tank port 11c straddles the first section S1 and the second section S2 and opens to the upper surface 11u of the housing 11. By providing the tank port 11c straddling both the first section S1 and the second section S2, the tank port 11c can be enlarged while still achieving a compact housing 11, thereby reducing 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 equal in size.

[0019] The tank port 11c is disposed closer to the second section S2 in the width direction of the housing 11 and is provided so as to extend from the second section S2 into the first section S1. By arranging the tank port 11c closer to the second section S2, the tank port 11c can be disposed closer to the second actuator port 11b than when the tank port 11c is disposed closer to the first section S1. This shortens the distance between the second actuator port 11b and the tank port 11c, thereby reducing the pressure loss of the hydraulic oil guided from the second actuator port 11b to the tank port 11c.

[0020] The first actuator port 11a and the second actuator port 11b have an installation portion A1 that has a counterbore and a female thread and to which a joint (not shown) is attached, and open to the upper surface 11u of the housing 11 through the installation portion A1. The tank port 11c has an installation portion A2 that has a counterbore and a female thread and to which a joint (not shown) is attached, and open to the upper surface 11u of the housing 11 through the installation portion A2.

[0021] On the top 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 of the tank port 11c in the longitudinal direction. The tank port 11c is provided on the other side of the housing 11 in the longitudinal direction (the lower side in FIG. 1 ). Meanwhile, the first actuator port 11a and the second actuator port 11b are provided on one side of the housing 11 in the longitudinal direction (the horizontal direction relative to the vertical direction) (the upper side in FIG. 1 ). By providing the first actuator port 11a and the second actuator port 11b on the top surface 11u of the housing 11 closer to one side in the longitudinal direction, more space can be secured on the other side in the longitudinal direction for the tank port 11c compared to, for example, a case in which the second actuator port 11b is aligned longitudinally with the first actuator port 11a and aligned widthwise with the tank port 11c. Therefore, the tank port 11c, which is provided on the other side in the longitudinal direction, can be enlarged while suppressing an increase in the size of the housing 11.

[0022] The first actuator port 11a, the second actuator port 11b, and the tank port 11c may open on an outer surface other than the top surface 11u of the housing 11, or may open on different surfaces. Even in this case, the tank port 11c can be made larger 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.

[0023] 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 in the longitudinal direction of the housing 11 (the upper side in FIG. 1).

[0024] When the first actuator port 11a is provided on one side in the longitudinal direction, by providing the second actuator port 11b adjacent to the tank port 11c from one side in the longitudinal direction (upper side in FIG. 1) on the other side in the longitudinal direction (lower side in FIG. 1) or by providing the second actuator port 11b near the center in the longitudinal direction, it is possible to suppress an increase in the size of the housing 11. Furthermore, when the second actuator port 11b is provided on one side in the longitudinal direction, by providing the first actuator port 11a adjacent to the tank port 11c diagonally (upper left in FIG. 1) on the top surface 11u of the housing 11 on the other side in the longitudinal direction (lower side in FIG. 1) or by providing the first actuator port 11a near the center in the longitudinal direction, it is possible to suppress an increase in the size of the housing 11 as much as possible compared to a case in which the second actuator port 11b is provided so as to be aligned with the first actuator port 11a in the longitudinal direction and aligned with the tank port 11c in the width direction. The first actuator port 11a can be provided near the center in the longitudinal direction of the first section S1 by shifting a compensator valve 61 (see FIG. 2) described later.

[0025] Instead of the hydraulic motor 4, for example, a hydraulic cylinder may be connected as an actuator to the valve unit 1. In this case, the first actuator port 11a and the second actuator port 11b both constitute supply / discharge ports for supplying / discharging hydraulic oil to / from the hydraulic cylinder, and when one supplies hydraulic oil to the hydraulic cylinder, the other discharges hydraulic oil from the hydraulic cylinder.

[0026] As shown in Fig. 2, the valve unit 1 has a control valve 5 incorporated inside a housing 11. The control valve 5 is a backup valve in the integrated valve block of the fluid pressure control device 100, and controls the operation of a hydraulic motor 4 (see Fig. 1) that drives a breaker that is attached to the hydraulic excavator as an attachment.

[0027] The control valve 5 has a spool valve 51 as a control spool whose position can be switched among a plurality of switching positions, and an accommodation hole 52 that slidably accommodates the spool valve 51. The control valve 5 has three switching positions: a neutral position (the state shown in FIG. 2 ) in which the spool valve 51 is in a neutral state, a first position in which the spool valve 51 is located on the other side in the longitudinal direction (the right side in FIG. 2 ) from the neutral position, and a second position in which the spool valve 51 is located on one side in the longitudinal direction (the left side in FIG. 2 ) from the neutral position. The first position is a supply position that supplies hydraulic oil to the hydraulic motor 4.

[0028] The spool valve 51 extends along the longitudinal direction of the housing 11. Therefore, the longitudinal direction of the housing 11 can be said to be the direction in which the spool valve 51 extends. The accommodating hole 52 is formed with an annular recess 53 provided in the center, a pump port 54 provided adjacent to the annular recess 53, supply ports 55 and 56 provided outside the annular recess 53 and the pump port 54, operating ports 57 and 58 provided outside the supply ports 55 and 56, discharge ports 81 a and 81 b provided outside the operating ports 57 and 58, and a first tank passage 81 communicating with the discharge ports 81 a and 81 b. In this embodiment, the discharge ports 81 a and 81 b are formed by the first tank passage 81.

[0029] The pump port 54 is connected to the pump 3 (see FIG. 1) through a pump passage 80 that extends in the width direction (left-right direction in FIG. 1) of the housing 11. Hydraulic oil discharged from the pump 3 is constantly guided to the pump port 54.

[0030] The first tank passage 81 is formed in the first section S1 (see FIGS. 1 and 4) of the housing 11. The discharge port 81a is provided adjacent to the operating port 57 on one side in the longitudinal direction (the left side in FIG. 2), and the discharge port 81b is provided adjacent to the operating port 58 on the other side in the longitudinal direction (the right side in FIG. 2).

[0031] The first tank passages 81 extend from the discharge ports 81a, 81b in a direction away from the spool valve 51 (downward in FIG. 2 ) and then extend substantially parallel to the spool valve 51 toward the inside of the housing 11 and connect to each other. The first tank passage 81 is connected to a fourth tank passage 84 and a fifth tank passage 85 extending in the width direction (see FIG. 1 ). 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 tank passage common to a plurality of control valves, etc., arranged in the width direction in the integrated valve block of the fluid pressure control device 100 (see FIG. 1 ). The housing 11 also has a second tank passage 82 (see FIG. 3 ) and a third tank passage 83 (see FIG. 4 ), which will be described later. The first to fifth tank passages 81 to 85 correspond to tank passages.

[0032] A first internal flow passage 91 that communicates with the actuation port 57 and the first actuator port 11a is formed in the housing 11. The first internal flow passage 91 is arranged on one side in the longitudinal direction together with the first actuator port 11a and the actuation port 57. The first actuator port 11a and the actuation port 57 overlap when viewed in the vertical direction (when viewed in the up-down direction in FIG. 2), and the first internal flow passage 91 extends approximately vertically (upward in FIG. 2) from the actuation port 57 to connect to the first actuator port 11a. Therefore, the actuation port 57 is connected to the pressure oil supply port 4a (see FIG. 1) of the hydraulic motor 4 through the first internal flow passage 91 and the first actuator port 11a.

[0033] 2 , the spool valve 51 has a first annular groove 51a formed in a position facing the pump port 54, a second annular groove 51b formed in a position facing the annular recess 53, a third annular groove 51c formed in a position facing the operating port 57, a fourth annular groove 51d formed in a position facing the operating port 58, and a fifth annular groove 51e formed in a position facing a signal pressure passage P, which will be described later. A first pilot chamber 21 and a centering spring 22 are provided at one end of the spool valve 51, and a second pilot chamber 23 and a centering spring 24 are provided at the other end of the spool valve 51. Pilot pressure is supplied to the first pilot chamber 21 via a first solenoid 62, and pilot pressure is supplied to the second pilot chamber 23 via a second solenoid 63. In the neutral position, the operating ports 57 and 58 are blocked by the spool valve 51 from the supply ports 55 and 56 and the exhaust ports 81a and 81b.

[0034] The control valve 5 further has a valve accommodating hole 60 formed perpendicular to the accommodating hole 52, and a compensator valve 61 slidably accommodated in the valve accommodating hole 60. The annular recess 53 and the supply ports 55, 56 communicate with each other through the compensator valve 61, and the degree of communication between them changes according to the pressure of the hydraulic oil acting on the compensator valve 61.

[0035] When pilot pressure is introduced into the first pilot chamber 21 and the spool valve 51 moves to the other side in the longitudinal direction (the right side in FIG. 2 ) and assumes the first position, the pump port 54 and the annular recess 53 communicate with each other through the first annular groove 51 a and a notch (not shown) communicating with the first annular groove 51 a, and hydraulic oil is introduced to the supply ports 55 and 56. The hydraulic oil introduced to the supply port 55 passes through the third annular groove 51 c and the operating port 57 communicating with the supply port 55, and is then supplied to the pressure oil supply port 4 a of the hydraulic motor 4 (see FIG. 1 ) through the first internal flow path 91 and the first actuator port 11 a. The hydraulic oil supplied to the hydraulic motor 4 is then introduced from the pressure oil discharge port 4 b of the hydraulic motor 4 to the second actuator port 11 b (see FIGS. 1 and 3 ).

[0036] As shown in Figure 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 alongside the control valve 5 in the width direction of the housing 11 (see Figure 4). Therefore, the width direction can be said to be the direction in which the control valve 5 and the quick return valve 7 are lined up.

[0037] The quick return valve 7 has a spool valve 71 as a quick return spool whose position can be switched between a plurality of switching positions, and an accommodation hole 72 that slidably accommodates the spool valve 71. The quick return valve 7 has two switching positions: a neutral position (the state shown in FIG. 3 ) in which the spool valve 71 is in a neutral state, and a discharge position in which the spool valve 71 is located on one side in the longitudinal direction (the left side in FIG. 3 ) of the neutral position. Like the spool valve 51, the spool valve 71 extends along the longitudinal direction of the housing 11.

[0038] The accommodation 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 in the longitudinal direction (left side in FIG. 3 ), a discharge port 82a adjacent to the first connection port 73 from the other side in the longitudinal direction (right side in FIG. 3 ), and a second tank passage 82 communicating with the discharge port 82a. In this 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 in the longitudinal direction (right side in FIG. 3 ).

[0039] The second tank passage 82 is formed in the second section S2 (see FIGS. 1 and 4) of the housing 11. The discharge port 82a overlaps with the tank port 11c when viewed in the vertical direction (when viewed in the up-down 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.

[0040] The second tank passage 82 extends from the discharge port 82a in a direction away from the spool valve 71 (downward in FIG. 3), then extends substantially parallel to the spool valve 71 toward one side in the longitudinal direction (leftward in FIG. 3), and further extends substantially perpendicular to the spool valve 71 toward the spool valve 71 (upper in FIG. 3), passing around the spool valve 71, before connecting to a tank port 11d that opens on one side surface (the left side surface in FIG. 3) of the housing 11. The tank port 11d will be described later.

[0041] The second tank passage 82 is connected to a fourth tank passage 84 and a fifth tank passage 85, 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. In other words, like 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). Therefore, the second tank passage 82 is also connected to the first tank passage 81 through the fourth tank passage 84 and the fifth tank passage 85.

[0042] The housing 11 is formed with a second internal passage 92 (see FIGS. 3 and 4) that communicates between the second actuator port 11b and the operating port 58 (see FIG. 2) of the control valve 5. 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.

[0043] 3, the spool valve 71 has a first annular groove 71a formed in a position facing the discharge port 82a, a second annular groove 71b connecting the first connection port 73 and the second connection port 74, and a third annular groove 71c formed in a position facing the signal pressure passage P. A centering spring 25 is provided at one end (left side in FIG. 3) of the spool valve 71, and a pilot chamber 26 is provided at the other end (right side in FIG. 3) of the spool valve 71. Pilot pressure is supplied to the pilot chamber 26 via a solenoid 64.

[0044] When 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 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 from each other. Therefore, when the quick return valve 7 is in the discharge position, hydraulic oil introduced from the hydraulic motor 4 (see FIG. 1) through the second actuator port 11b to the second internal flow path 92 is discharged from the tank port 11c through the first connection port 73 and the second tank passage 82.

[0045] 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 pressure loss. The first connection port 73 corresponds to the second port, and is connected to and disconnected from the discharge port 82a by the spool valve 71.

[0046] The switching position of the quick return valve 7 can be changed by a user's switching operation using an operating unit such as a switch. The switching of the quick return valve 7 may be linked to the switching operation of the control valve 5, for example. By switching the quick return valve 7 from the neutral position to the discharge position in response to the switching of the control valve 5 from the neutral position to the first position, hydraulic oil can be discharged from the tank port 11c through the quick return valve 7 when the control valve 5 supplies hydraulic oil to the hydraulic motor 4 through the first actuator port 11a. Furthermore, by switching the quick return valve 7 from the discharge position to the neutral position in response to the switching of the control valve 5 from the first position to the neutral position, the quick return valve 7 can be returned to the neutral position when the control valve 5 stops supplying hydraulic oil.

[0047] 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 Figure 4) connecting the second connection port 74 of the quick return valve 7 and the operating port 58 of the control valve 5.

[0048] 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 with the spool valve 71 when viewed in the vertical direction (viewed from above and below in FIG. 3 ).

[0049] 4, the second partial flow path 92b extends from the second connection port 74 toward the operating port 58 at an angle (toward the lower right in FIG. 4) relative to the spool valve 71 and connects to the operating port 58. The second partial flow path 92b overlaps with the spool valve 51 of the control valve 5 and the spool valve 71 of the quick return valve 7 when viewed in the width direction (when viewed in the vertical direction in FIG. 4).

[0050] When the quick return valve 7 is in the neutral position shown in Fig. 3, the spool valve 71 communicates between the first connection port 73 and the second connection port 74 through the second annular groove 71b, and blocks the first connection port 73 from the discharge port 82a. Therefore, when the quick return valve 7 is switched to the neutral position, hydraulic oil from the second actuator port 11b is guided to the working port 58 of the control valve 5 through the second internal flow path 92. 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 working port 58 and the discharge port 81b communicate with each other through the fourth annular groove 51d.

[0051] 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 can be returned to the tank T (see FIG. 1) through the control valve 5. This provides the option of not using the quick return valve 7.

[0052] The operating port 58 is connected and disconnected from the discharge port 81b of the first tank passage 81 by the spool valve 51, and is disconnected from the hydraulic oil supply port 56 when connected to the discharge port 81b of the first tank passage 81, and is disconnected from the discharge port 81b of the first tank passage 81 when connected to the supply port 56. Therefore, the second actuator port 11b, which is connected to the operating port 58 through the second internal flow path 92, can also function as a supply / discharge port. The operating port 58 corresponds to the first port.

[0053] 4, the discharge port 81b of the first tank passage 81 and the discharge port 82a of the second tank passage 82 are connected to each other through the third tank passage 83. Therefore, when hydraulic oil is discharged from the control valve 5 through the discharge port 81b of the first tank passage 81, the hydraulic oil can also be easily discharged from the tank port 11c through the third tank passage 83. This allows the control valve 5 to also utilize the tank port 11c to reduce pressure loss.

[0054] The discharge port 82a of the second tank passage 82 is set to have a dimension along the longitudinal direction (the dimension in the left-right direction in FIG. 4 ) larger than the discharge port 81b of the first tank passage 81. This makes it possible to reduce pressure loss when the hydraulic oil is discharged through the discharge port 82a of the second tank passage 82 compared to when the hydraulic oil is discharged through the discharge port 81b of the first tank passage 81.

[0055] 3 is provided on one side in the longitudinal direction, so hydraulic oil closer to the tank port 11d can be discharged more quickly than the tank port 11c provided on the other side in the longitudinal direction. On the other hand, the quick return valve 7 is required to quickly discharge hydraulic oil to handle the large flow rate returned from the hydraulic motor 4. 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. Because the tank port 11c has a larger cross-sectional area than the tank port 11d, pressure loss of the hydraulic oil discharged through the tank port 11c is reduced compared to when hydraulic oil is discharged through the tank port 11d or when a tank port of the same size as the tank port 11d is provided instead of the tank port 11c.

[0056] If, for example, a hydraulic cylinder is used as the 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 hydraulic oil to the hydraulic cylinder, and the second actuator port 11b functions as a discharge port for hydraulic oil from the hydraulic cylinder. Therefore, in this case as well, hydraulic oil from the second actuator port 11b is discharged through the discharge port 81b of the first tank passage 81. In this case, if the quick return valve 7 is switched to the discharge position, hydraulic oil discharged from the hydraulic cylinder can also be discharged from the tank port 11c through the quick return valve 7.

[0057] When a hydraulic cylinder is used as an actuator, if the control valve 5 is set to the second position while the quick return valve 7 is 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:

[0058] That is, when 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 51 b and a notch (not shown) communicating with the second annular groove 51 b, and hydraulic oil is introduced to the supply ports 55 and 56. The hydraulic oil introduced to the supply port 56 passes through the fourth annular groove 51 d and the actuation port 58 communicating with the supply port 56, and is then supplied to the hydraulic cylinder through the second partial flow path 92 b, the second connection port 74, the first connection port 73, the first partial flow path 92 a, and the second actuator port 11 b (see FIGS. 3 and 4 ). From the hydraulic cylinder, the hydraulic oil is introduced to the first actuator port 11 a, and then introduced to the first tank passage 81 through the first internal flow path 91, the actuation port 57, and the third annular groove 51 c.

[0059] Relief valves (not shown) can be provided on both side surfaces of the housing 11 (left and right side surfaces in FIG. 2 ), and 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 a set pressure, thereby communicating the first internal flow path 91 with the first tank passage 81 extending from the discharge port 81 a in a direction away from the spool valve 51 (upper side in FIG. 2 ). 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 (upper side in FIG. 2 ) from the operating port 58 is equal to or higher than a set pressure, thereby communicating the third internal flow path 93 with the first tank passage 81 extending from the discharge port 81 b in a direction away from the spool valve 51 (upper side in FIG. 2 ).

[0060] As shown in Fig. 4, the valve unit 1 further includes a signal pressure passage P that is formed in the housing 11 and extends across the spool valve 71 of the quick return valve 7, and that is connected or disconnected by the spool valve 51 of the control valve 5 depending on the switching position of the control valve 5. The signal pressure passage P extends along the width direction and opens to one end face (the lower face in Fig. 4) and the other end face (the upper face in Fig. 4) of the housing 11. The signal pressure passage P is provided to detect the neutral position of the control valve 5, and is connected via 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 and the quick return valve 7 are in the neutral position shown in Fig. 4, and is disconnected by the spool valve 51 when the control valve 5 is switched from the neutral position to the first position or the second position.

[0061] 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 communicates with the fifth annular groove 51e across the spool valve 71. 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).

[0062] When the control valve 5 is in the neutral position, the first partial passage P1 and the second partial passage P2 communicate with the fifth annular groove 51e while being offset from each other on opposite sides of the center of the fifth annular groove 51e in the longitudinal direction. The first partial passage P1 is offset from the center of the fifth annular groove 51e to the left in FIG. 4, and the second partial passage P2 is offset from the center of the fifth annular groove 51e to the right in FIG. 4. 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.

[0063] When the spool valve 51 moves to the left in Fig. 4, the second partial passage P2 on the upper side in Fig. 4 is blocked from the fifth annular groove 51e by the spool valve 71 before the first partial passage P1 on the lower side in Fig. 4 is blocked from the fifth annular groove 51e by the spool valve 71. When the spool valve 51 moves to the right in Fig. 4, the first partial passage P1 on the lower side in Fig. 4 is blocked from the fifth annular groove 51e by the spool valve 71 before the second partial passage P2 on the upper side 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 when moving to the other side in the longitudinal direction from the neutral position.

[0064] The third annular groove 71c of the spool valve 71 is a signal pressure annular groove, and the groove width (width in the left-right direction in FIG. 4 ) of the third annular groove 71c is set to a size that maintains the second partial passage P2 in a communicated state both when the spool valve 71 is in the neutral position and when it is in the discharge position. In other words, the third annular groove 71c communicates with the signal pressure passage P regardless of the switching position of the quick return valve 7. As a result, even if the spool valve 71 is provided across 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 in a location that avoids the signal pressure passage P, and the layout flexibility of the spool valve 71 and the signal pressure passage P is improved.

[0065] The configuration, operation, and effects of the embodiment of the present invention will be described below.

[0066] The valve unit 1 includes a housing 11, a first actuator port 11a that opens onto 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 onto the outer surface of the housing 11 and is connected to the hydraulic motor 4, a tank port 11c that opens onto the outer surface of the housing 11 and is connected to a tank T, a control valve 5 that is incorporated inside the housing 11 and controls the operation of the hydraulic motor 4, and a quick return valve 7 that is incorporated inside the housing 11 and returns 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 onto the outer surface of the housing 11, spanning a first section S1 of the housing 11 in which the control valve 5 is provided and a second section S2 of the housing 11 in which the quick return valve 7 is provided.

[0067] According to this configuration, the control valve 5 and the quick return valve 7 are provided in the housing 11, which is a single housing (monoblock), eliminating the need for piping between the control valve 5 and the quick return valve 7. Furthermore, since a tank port 11c is provided that spans both the control valve 5 and the quick return valve 7 sections, the tank port 11c can be enlarged while still achieving a compact housing 11, thereby reducing the pressure loss of the working fluid discharged into the tank T.

[0068] The first actuator port 11a, the second actuator port 11b, and the tank port 11c are formed on the top 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.

[0069] According to this configuration, space can be secured on the other side of the housing 11 in the longitudinal direction to provide the tank port 11c, so that the tank port 11c can be made larger while suppressing an increase in the size of the housing 11.

[0070] The first actuator port 11a and the second actuator port 11b are provided on one side of the tank port 11c in the longitudinal direction of the housing 11. The valve unit 1 further includes first to fifth tank passages 81 to 85 formed in the housing 11 and communicating with the tank port 11c. The control valve 5 includes a spool valve 51 which is a control spool, a hydraulic oil supply port 56, and an actuation port 58 (first port) which is provided on the other side in the longitudinal direction and which is blocked from the first tank passage 81 by the spool valve 51 when in communication with the supply port 56 and which is blocked from the supply port 56 when in communication with the first tank passage 81. The quick return valve 7 includes a spool valve 71 which is a quick return spool and a first connection port 73 (second port) which is provided on the other side in the longitudinal direction and which is connected to and disconnected from a 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, which is located on one side of the tank port 11c in the longitudinal direction, to the operating port 58, which is located on the other side, through the first connection port 73.

[0071] According to this configuration, when the tank port 11c is provided on the other side in the longitudinal direction, even if the first actuator port 11a and the second actuator port 11b are provided on one side of the tank port 11c in the longitudinal direction, by providing the second internal flow path 92 extending from one side of the tank port 11c in the longitudinal direction to the other side in the longitudinal direction, as described above, the second actuator port 11b can be connected to the tank port 11c through the quick return valve 7 and the control valve 5. Furthermore, since the actuation port 58 is connected to and disconnected from the supply port 56, the second actuator port 11b can also be used as a supply / discharge port for hydraulic oil depending on the actuator to be applied.

[0072] The valve unit 1 further includes a signal pressure passage P that is formed in the housing 11, extends across the spool valve 71, and is connected or disconnected by the spool valve 51 depending on 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 is connected to the signal pressure passage P regardless of the switching position of the quick return valve 7.

[0073] According to this configuration, even if the spool valve 71 is provided so as to cross the signal pressure passage P, the third annular groove 71c of the spool valve 71 does not block the signal pressure passage P, so it is possible to detect the switching position of the control valve 5. Therefore, it is not necessary to provide the spool valve 71 in a way that avoids the signal pressure passage P, and the layout flexibility of the spool valve 71 and the signal pressure passage P is improved.

[0074] Although the embodiments of the present invention have been described above, the above embodiments merely illustrate some of the application examples of the present invention, and it is not intended that the technical scope of the present invention be limited to the specific configurations of the above embodiments.

[0075] This application claims priority based on Japanese Patent Application No. 2023-204448, filed with the Japan Patent Office on December 4, 2023, the entire contents of which are incorporated herein by reference.

Claims

1. A valve unit comprising: a housing; a first actuator port opening onto an outer surface of the housing and connected to an actuator; a second actuator port opening onto the outer surface of the housing and connected to the actuator; a tank port opening onto the outer surface of the housing and connected to a tank; a control valve installed inside the housing and controlling the operation of the actuator; and a quick return valve installed inside the housing for returning working fluid from the second actuator port to the tank through the tank port without passing through the control valve, wherein the tank port opens onto the outer surface of the housing, spanning a first section of the housing in which the control valve is provided and a second section of the housing in which the quick return valve is provided.

2. A valve unit as claimed in 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 of the housing in the longitudinal direction, and the tank port is provided on the other side of the housing in the longitudinal direction.

3. A valve unit as claimed in claim 2, wherein the first actuator port and the second actuator port are provided on one side of the tank port in the longitudinal direction, and the housing further comprises a tank passage formed in the housing and communicating with the tank port, the control valve having a control spool, a supply port for working fluid, and a first port provided on the other side in the longitudinal direction, the first port being blocked by the control spool from the tank passage in a state of communication with the supply port, and being blocked from the supply port in a state of communication with the tank passage, the quick return valve having a quick return spool and a second port provided on the other side in the longitudinal direction, the second port being connected to and blocked from the tank passage by the quick return spool, and the housing has an internal flow path connecting the second actuator port provided on one side of the tank port in the longitudinal direction to the first port provided on the other side in the longitudinal direction through the second port.

4. A valve unit as claimed in claim 1, further comprising a signal pressure passage formed in the housing, arranged across the quick return spool of the quick return valve, and connected or blocked by the control spool of the control valve depending on the switching position of the control valve, and the quick return spool has a signal pressure annular groove that connects with the signal pressure passage regardless of the switching position of the quick return valve.

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