Inlet block and valve device

Abstract

An inlet block (100) comprises: a confluence control valve (21) that combines or blocks working fluid discharged from a first pump (111) and working fluid discharged from a second pump (114); a first unloading valve (31) connected to a first fluid pressure passage; a second unloading valve (32) connected to a second fluid pressure passage; and a valve body (151) in which the first fluid pressure passage and the second fluid pressure passage are formed and the confluence control valve (21), the first unloading valve (31), and the second unloading valve (32) are mounted. The confluence control valve (21) is mounted away from the first unloading valve (31) and the second unloading valve (32) in a perpendicular direction that is perpendicular to the parallel direction in which the first unloading valve (31) and the second unloading valve (32) are arranged and to the axial direction of the first unloading valve (31) and the second unloading valve (32), and is interposed between the first unloading valve (31) and the second unloading valve (32) in the parallel direction.

Description

Inlet Block and Valve Unit

[0001] The present invention relates to an inlet block and a valve device.

[0002] JP2019-56436A discloses a hydraulic system including a first fluid pressure circuit that controls multiple actuators, a second fluid pressure circuit that controls multiple actuators, and a control valve that merges or blocks hydraulic oil supplied to the first fluid pressure circuit and the second fluid pressure circuit. The hydraulic system includes a pump, a valve unit that controls each actuator, and a tank. The valve unit includes an inlet block for taking in hydraulic oil, an unloading block, a valve block that controls each actuator, and an outlet block for discharging oil. The inlet block includes a merger control valve that merges or blocks the first fluid pressure circuit and the second fluid pressure circuit, and the unloading block includes a first unloading valve that unloads hydraulic oil from the first fluid pressure circuit and a second unloading valve that unloads hydraulic oil from the second fluid pressure circuit.

[0003] In the hydraulic system described in JP2019-56436A, the confluence control valve is provided in the inlet block, and the first unloading valve and the second unloading valve are provided in the unloading block aligned with the inlet block. As a result, the valve unit becomes longer in one direction (specifically, the direction in which the inlet block and the unloading block are aligned), which takes up space.

[0004] An object of the present invention is to reduce the dimension of the valve block in one direction.

[0005] According to one aspect of the present invention, there is provided an inlet block comprising: a confluence control valve that confluences or blocks the flow of a working fluid discharged from a first pump through a first fluid pressure passage and a working fluid discharged from a second pump through a second fluid pressure passage; a first unloading valve connected to the first fluid pressure passage and that unloads the working fluid discharged from the first pump; a second unloading valve connected to the second fluid pressure passage and that unloads the working fluid discharged from the second pump; and a valve body in which the first fluid pressure passage and the second fluid pressure passage are formed and in which the confluence control valve, the first unloading valve, and the second unloading valve are provided, wherein the first unloading valve and the second unloading valve are arranged side by side with their axes parallel to each other, and the confluence control valve is arranged apart from the first unloading valve and the second unloading valve in a vertical direction that is perpendicular to the parallel direction in which the first unloading valve and the second unloading valve are arranged and to the axial direction of both, and is arranged between the first unloading valve and the second unloading valve in the parallel direction.

[0006] FIG. 1 is a fluid pressure circuit diagram of a hydraulic system including an inlet block according to this embodiment. FIG. 2 is a plan view of the inlet block. FIG. 3 is a front view of the inlet block. FIG. 4 is a cross-sectional view taken along line IV-IV in FIG. 2. FIG. 5 is a cross-sectional view taken along line V-V in FIG. 3, showing a state in which the spool is in the communicating position (Y). FIG. 6 is a cross-sectional view taken along line VI-VI in FIG. 2, showing a state in which the spool is in the communicating position (Y). FIG. 7 is a cross-sectional view taken along line VII-VII in FIG. 3. FIG. 8 is a cross-sectional view taken along line VIII-VIII in FIG. 3. FIG. 9 is a cross-sectional view taken along line IX-IX in FIG. 3. FIG. 10 is a side view of the inlet block as viewed from the arrow X in FIG. 3.

[0007] A hydraulic system 1 including an inlet block 100 according to an embodiment of the present invention will be described with reference to the drawings. The hydraulic system 1 is mounted on construction machinery, agricultural machinery, industrial machinery, etc. Below, an example of a hydraulic system 1 mounted on a hydraulic excavator for operating various actuators of the hydraulic excavator will be described. In the following embodiment, an example will be described in which hydraulic oil is used as the working fluid, but other fluids such as hydraulic water may also be used as the working fluid.

[0008] 1, the hydraulic circuits of the hydraulic system 1 include a first hydraulic circuit HC1 that receives hydraulic oil from a first pump 111 and controls a plurality of actuators MR, AS, and a second hydraulic circuit HC2 that receives hydraulic oil from a second pump 114 and controls a plurality of actuators ML, BS. The hydraulic oil supplied to the first hydraulic circuit HC1 and the hydraulic oil supplied to the second hydraulic circuit HC2 are merged or blocked by a merge control valve 21, which will be described later. First, the first hydraulic circuit HC1 and the second hydraulic circuit HC2 will be described.

[0009] The first hydraulic circuit HC1 is a circuit that controls the drive of actuators such as the right-side travel motor MR and the arm cylinder AS, and the second hydraulic circuit HC2 is a circuit that controls the drive of actuators such as the left-side travel motor ML and the boom cylinder BS.

[0010] The first hydraulic circuit HC1 has a first pump 111 as a hydraulic pressure supply source, a first main supply passage 121a as a first fluid pressure passage, a tank passage 122a, a control valve 110a, a control valve 110b, and a first unloading valve 31.

[0011] The first pump 111 is a piston pump, and its discharge capacity changes when the inclination of a swash plate 113a is changed by a regulator 113. The regulator 113 receives the higher of the maximum discharge pressures of the first pump 111 and the second pump 114 and the maximum load pressures of the actuators MR, AS, ML, and BS, and the discharge capacity of the first pump 111 is controlled by so-called load sensing control so that the differential pressure between the maximum discharge pressure and the maximum load pressure becomes a predetermined value. Note that the circuit that guides the maximum discharge pressure to the regulator 113 is not shown in FIG. 1 .

[0012] The first main supply passage 121a is connected to a first discharge port 111a of the first pump 111, and hydraulic oil discharged from the first discharge port 111a is supplied to each of the actuators MR, AS. The tank passage 122a is connected to a tank 112, and guides hydraulic oil discharged from each of the actuators MR, AS to the tank 112. The control valve 110a controls the flow of hydraulic oil supplied from the first main supply passage 121a to the right-side traveling motor MR, and the control valve 110b controls the flow of hydraulic oil supplied from the first main supply passage 121a to the arm cylinder AS. The control valves 110a, 110b are switched by, for example, a pilot pressure output in response to operation of an operating lever (not shown).

[0013] The first unloading valve 31 unloads the hydraulic oil discharged from the first pump 111. The maximum load pressure of the first hydraulic circuit HC1 is input to the first unloading valve 31, and when the pressure in the first main supply passage 121a becomes higher than the maximum load pressure of the first hydraulic circuit HC1 by a predetermined value or more, the first unloading valve 31 opens and unloads the hydraulic oil discharged from the first pump 111.

[0014] The second hydraulic circuit HC2 has a second pump 114 as a hydraulic supply source, a second main supply passage 121b as a second fluid pressure passage, a tank passage 122b, control valves 120a and 120b, and a second unloading valve 32.

[0015] The second pump 114 has a configuration similar to that of the first pump 111. The regulator is supplied with the maximum discharge pressure of either the first pump 111 or the second pump 114, whichever is higher, and the maximum load pressure of each of the actuators MR, AS, ML, and BS. The discharge capacity of the second pump 114 is controlled by so-called load sensing control so that the differential pressure between the maximum discharge pressure and the maximum load pressure becomes a predetermined value. Note that the regulator and the circuit that supplies the maximum discharge pressure to the regulator are not shown in FIG. 1 .

[0016] The second main supply passage 121b is connected to a second discharge port 114a of the second pump 114, and hydraulic oil discharged from the second discharge port 114a is supplied to each of the actuators ML, BS. The tank passage 122b is connected to the tank passage 122a and the tank 112, and guides hydraulic oil discharged from each of the actuators ML, BS to the tank 112. The control valve 120a controls the flow of hydraulic oil supplied from the second main supply passage 121b to the left traveling motor ML, and the control valve 120b controls the flow of hydraulic oil supplied from the second main supply passage 121b to the boom cylinder BS. The control valves 120a, 120b are switched by, for example, a pilot pressure output in response to operation of an operating lever (not shown).

[0017] The second unloading valve 32 unloads the hydraulic oil discharged from the second pump 114. The maximum load pressure of the second hydraulic circuit HC2 is input to the second unloading valve 32, and when the pressure in the second main supply passage 121b becomes higher than the maximum load pressure of the second hydraulic circuit HC2 by a predetermined value or more, the second unloading valve 32 opens and unloads the hydraulic oil discharged from the second pump 114.

[0018] A first sub-supply passage 161a is connected to the first main supply passage 121a, and is supplied with hydraulic oil discharged from the first pump 111. A second sub-supply passage 161b is connected to the second main supply passage 121b, and is supplied with hydraulic oil discharged from the second pump 114. A confluence control valve 21 is provided between the first sub-supply passage 161a and the second sub-supply passage 161b, and switches between merging and blocking the first sub-supply passage 161a and the second sub-supply passage 161b.

[0019] As will be described later, the confluence control valve 21 is a pilot-operated directional control valve in which a spool 153 (see FIGS. 5 and 6 ) slidably housed in a main housing bore 152 (see FIGS. 5 and 6 ) formed in a valve body 151 is switched between a communication position (Y) and a cutoff position (X). When the confluence control valve 21 is in the communication position (Y), the first sub-supply passage 161a and the second sub-supply passage 161b are connected to each other, thereby connecting the first hydraulic circuit HC1 and the second hydraulic circuit HC2. In other words, the confluence control valve 21 connects the first hydraulic circuit HC1 and the second hydraulic circuit HC2 and allows the hydraulic oil discharged from the first pump 111 and the hydraulic oil discharged from the second pump 114 to be connected together. When the confluence control valve 21 is in the shutoff position (X), communication between the first sub-supply passage 161a and the second sub-supply passage 161b is blocked, thereby blocking communication between the first hydraulic circuit HC1 and the second hydraulic circuit HC2.

[0020] A check passage 55, in which a first check valve 51 and a second check valve 52 are provided, is connected between the upstream side of the first unloading valve 31 in the first main supply passage 121a and the upstream side of the second unloading valve 32 in the second main supply passage 121b. Furthermore, a relief passage 62, in which a relief valve 60 is provided, is connected between the tank passage 163 and a section of the check passage 55 between the first check valve 51 and the second check valve 52. The first check valve 51 allows hydraulic oil to flow only from the first main supply passage 121a to the relief passage 62, and the second check valve 52 allows hydraulic oil to flow only from the second main supply passage 121b to the relief passage 62. Therefore, hydraulic oil having a higher pressure from either the first main supply passage 121a or the second main supply passage 121b is guided to the relief passage 62, and the guided hydraulic oil is relieved by the relief valve 60. That is, the relief valve 60 relieves the higher pressure from either the first main supply passage 121 a or the second main supply passage 121 b. In other words, the relief valve 60 determines the maximum pressure in the first hydraulic circuit HC1 and the second hydraulic circuit HC2.

[0021] The hydraulic circuit of the hydraulic system 1 includes a first load pressure passage 162a to which the highest load pressure of the load pressures of the multiple actuators MR, AS controlled by the first hydraulic circuit HC1 is guided, a second load pressure passage 162b to which the highest load pressure of the load pressures of the multiple actuators ML, BS controlled by the second hydraulic circuit HC2 is guided, and a load pressure selection valve 35. Note that in Figure 1, illustration of circuits that guide the load pressures to the first load pressure passage 162a and the second load pressure passage 162b is omitted.

[0022] The first load pressure passage 162a and the second load pressure passage 162b are connected to the load pressure selection valve 35. The load pressure selection valve 35 is a high-pressure selection valve that selects the higher of the maximum load pressure of the first hydraulic circuit HC1 and the maximum load pressure of the second hydraulic circuit HC2. The maximum load pressure selected by the load pressure selection valve 35 is guided through the maximum load pressure passage 35a to the regulator 113 of the first pump 111 and the regulator of the second pump 114, and is used to control the inclination angle of the swash plate 113a of the first pump 111 and the swash plate (not shown) of the second pump 114.

[0023] A first pressure relief passage 164a is connected to the first load pressure passage 162a to prevent pressure from building up. Similarly, a second pressure relief passage 164b is connected to the second load pressure passage 162b to prevent pressure from building up. The first pressure relief passage 164a and the second pressure relief passage 164b are each connected to the tank 112 via a tank passage 122a. A first throttle 131 is provided in the first pressure relief passage 164a to maintain the pressure in the first load pressure passage 162a, and a second throttle 132 is provided in the second pressure relief passage 164b to maintain the pressure in the second load pressure passage 162b.

[0024] Next, the valve device 10 that constitutes the hydraulic system 1 will be described.

[0025] As shown in Fig. 1, the valve device 10 includes an inlet block 100 for taking in pressure oil and actuator blocks B11, B12, B21, and B22 corresponding to the actuators MR, AS, ML, and BS. In Fig. 1, the boundaries between the inlet block 100 and the actuator blocks B11, B12, B21, and B22 are indicated by two-dot chain lines. The inlet block 100 is the block to which hydraulic oil discharged from the first pump 111 and the second pump 114 is first supplied, and the hydraulic oil is then supplied from the inlet block 100 to the actuator blocks B11, B12, B21, and B22. The actuator blocks B11 and B12 are disposed on one side of the inlet block 100, and the actuator blocks B21 and B22 are disposed on the other side of the inlet block 100. The inlet block 100 and the actuator blocks B11, B12, B21, and B22 are connected by bolts or the like to constitute the valve device 10.

[0026] The inlet block 100 includes the confluence control valve 21, the first unloading valve 31, the second unloading valve 32, the first check valve 51, the second check valve 52, the relief valve 60, and the load pressure selection valve 35. The inlet block 100 also includes the first main supply passage 121a, the first sub-supply passage 161a, the check passage 55, the relief passage 62, the first load pressure passage 162a, the second load pressure passage 162b, the first pressure relief passage 164a, the second pressure relief passage 164b, the first throttle 131, the second throttle 132, and the tank passage 122a. The configuration of the valve body 151 will be described in detail below.

[0027] The actuator block B11 includes the control valve 110a, the first main supply passage 121a, the first load pressure passage 162a, and the tank passage 122a. The actuator block B12 includes the control valve 110b, the first main supply passage 121a, the first load pressure passage 162a, and the tank passage 122a. The actuator block B21 includes the control valve 120a, the second main supply passage 121b, the second load pressure passage 162b, and the tank passage 122b. The actuator block B22 includes the control valve 120b, the second main supply passage 121b, the second load pressure passage 162b, and the tank passage 122b.

[0028] The valve device 10 also includes a valve block that controls actuators (not shown) that drive a swing motor that swings the hydraulic excavator, a bucket, a dozer, etc. (not shown), but these are not shown in FIG. 1.

[0029] Next, the specific structure of the inlet block 100 will be described with reference to FIGS.

[0030] FIG. 2 is a plan view of the inlet block 100, and FIG. 3 is a front view of the inlet block 100. FIG. 4 is a cross-sectional view taken along line IV-IV in FIG. 2, FIG. 5 is a cross-sectional view taken along line V-V in FIG. 3, FIG. 6 is a cross-sectional view taken along line VI-VI in FIG. 2, FIG. 7 is a cross-sectional view taken along line VII-VII in FIG. 3, FIG. 8 is a cross-sectional view taken along line VIII-VIII in FIG. 3, and FIG. 9 is a cross-sectional view taken along line IX-IX in FIG. 3. FIG. 10 is a side view of the inlet block 100 as seen from the arrow X in FIG. 3. FIGS. 5, 7-9 are shown in the same orientation as FIG. 2, and FIGS. 4 and 6 are shown in the same orientation as FIG. 3. Note that, hereinafter, for convenience of explanation, the up-down direction in FIG. 2 will also be referred to as the D1 direction, the left-right direction in FIG. 2 as the D2 direction, and the direction perpendicular to the paper surface in FIG. 2 as the D3 direction.

[0031] 2, a first pump port 260a communicating with the first pump 111 and a second pump port 260b communicating with the second pump 114 are formed and open on the upper surface 151a of the valve body 151 of the inlet block 100. Pipes are connected to the first pump port 260a and the second pump port 260b, respectively, and communicate with the first pump 111 and the second pump 114. In addition, a first load pressure port 234a communicating with the first load pressure passage 162a and a second load pressure port 234b communicating with the second load pressure passage 162b are formed and open on the upper surface 151a of the valve body 151.

[0032] As shown in Figure 4, the valve body 151 has a first supply passage 261a formed in communication with the first pump port 260a, and a second supply passage 262a (see Figure 5) formed in communication with the second pump port 260b. The first supply passage 261a corresponds to the first main supply passage 121a and the first sub-supply passage 161a of the hydraulic circuit shown in Figures 1 and 2, and the second supply passage 262a corresponds to the second main supply passage 121b and the second sub-supply passage 161b of the hydraulic circuit shown in Figures 1 and 2. The first supply passage 261a and the second supply passage 262a are symmetrical with respect to the main accommodation bore 152.

[0033] The first supply passage 261a is formed in a branched manner. Specifically, the first supply passage 261a includes a main passage 261b extending substantially linearly in the direction D3 from the first pump port 260a to the first unloading valve 31, a first sub-passage 261c extending in the direction D2 from the main passage 261b to the first check valve 51, and a second sub-passage 261d (see FIG. 5) extending in the direction D1 from the main passage 261b to the main accommodation hole 152 in which the spool 153 is slidably accommodated and to the back surface 151c of the valve body 151. As shown in FIG. 5, a first supply port 221a communicating with the second sub-passage 261d is formed and opens in the back surface 151c of the valve body 151. The hydraulic oil supplied from the first pump port 260a is guided to the first unloading valve 31, the main accommodating hole 152, the first supply port 221a, and the first check valve 51 through a first supply passage 261a.

[0034] Similar to the first supply passage 261a, the second supply passage 262a includes a main passage 262b (see FIG. 7) extending substantially linearly in the direction D3 from the second pump port 260b to the second unloading valve 32, a first sub-passage (not shown) extending in the direction D2 from the main passage 262b to the second check valve 52, and a second sub-passage 262d (see FIG. 5) extending in the direction D1 from the main passage 262b to the main accommodation hole 152 and the front face 151b of the valve body 151. The main passage 262b and the first sub-passage 262c correspond to the second main supply passage 121b of the hydraulic circuit shown in FIG. 1, and the second sub-passage 262d corresponds to the second sub-supply passage 161b. As shown in FIG. 5, a second supply port 221b communicating with the second sub-passage 262d is formed and opens in the front face 151b of the valve body 151. The hydraulic oil supplied from the second pump port 260b is guided to the second unloading valve 32, the main accommodating hole 152, the second supply port 221b, and the second check valve 52 through a second supply passage 262a.

[0035] As shown in FIGS. 6, 7, and 9, the valve body 151 has a first load pressure passage 162a and a second load pressure passage 162b. Hydraulic oil is guided to the first load pressure passage 162a and the second load pressure passage 162b through load pressure ports 166a, 166b (see FIG. 9) formed on the outer surface of the valve body 151, respectively. The first load pressure passage 162a and the second load pressure passage 162b are formed extending in directions D2 and D1 on the cross section shown in FIG. 9, and are also formed extending in direction D3 from the cross section (see the first load pressure passage 162a in FIG. 4). The first load pressure passage 162a is connected to the first unloading valve 31 (see FIGS. 4 and 8), the main accommodating bore 152 (see FIGS. 5 and 6), the load pressure selection valve 35 (see FIG. 7), and the first orifice 131 (see FIG. 9). The second load pressure passage 162b similarly communicates with the second unloading valve 32 (see Figure 8), the main accommodating hole 152 (see Figures 5 and 6), the load pressure selection valve 35 (see Figure 7), and the second throttle 132 (see Figure 9).

[0036] 7, the valve body 151 is provided with a load pressure port 165 that leads the maximum load pressure selected by the load pressure selection valve 35 to the outside. The load pressure port 165 is in communication with the load pressure selection valve 35 and is provided on one side surface 151d of the valve body 151. The load pressure port 165 leads the maximum load pressure to the regulator 113 of the first pump 111 and the regulator of the second pump 114, respectively.

[0037] As shown in Fig. 6, the valve body 151 has a tank passage 122a that communicates with the tank 112. The tank passage 122a is formed in a Y-shape and communicates with the main accommodating hole 152 in the cross section shown in Fig. 6. As shown in Fig. 8, the tank passage 122a is formed to extend in the D1 direction between the first unloading valve 31 and the second unloading valve 32, and when the first unloading valve 31 and the second unloading valve 32 are opened, the tank passage 122a guides the hydraulic oil from the first supply passage 261a and the second supply passage 262a, respectively, to the tank 112. In other words, the tank passage 122a is formed between a first accommodating hole 231 and a second accommodating hole 232, which will be described later, in which the first unloading valve 31 and the second unloading valve 32 are accommodated, respectively. 9, the tank passage 122a is formed extending in the D1 direction between the first orifice 131 and the second orifice 132, and guides the hydraulic oil in the first load pressure passage 162a and the second load pressure passage 162b to the tank 112 through the first orifice 131 and the second orifice 132. Tank ports 223a, 223b communicating with the tank passage 122a are formed in the upper surface 151a of the valve body 151 (see FIGS. 2 and 6), and a tank port 223c communicating with the tank passage 122a is formed in the front surface 151b of the valve body 151 (see FIG. 3).

[0038] As shown in Figures 5 and 6, the main accommodating hole 152 is connected to a first supply passage 261a, a second supply passage 262a, a first load pressure passage 162a, a second load pressure passage 162b, and a tank passage 122a, and this communication is blocked by a first land portion 171, a second land portion 172, and a third land portion 173 provided on the spool 153. One opening of the main accommodating hole 152 (the right side in Figures 5 and 6) is closed by a first pilot cap 170a provided with a drain chamber 21a connected to the tank 112. The other opening (the left side in Figures 5 and 6) is closed by a second pilot cap 170b provided with a pilot chamber 21b to which pilot pressure is input for switching the spool 153 to the disconnect position (X). The first pilot cap 170a is provided with a spring 154 that biases the spool 153 in a direction switching it from the disconnect position (X) to the communicating position (Y). The spool 153 moves in the axial direction in response to the pilot pressure input to the pilot chamber 21b.

[0039] The first land portion 171 establishes or blocks communication between the adjacent first supply passage 261a and second supply passage 262a. When pilot pressure is not conducted to the pilot chamber 21b and the spool 153 is in the communication position (Y) as shown in Figures 5 and 6, the first supply passage 261a and the second supply passage 262a communicate with each other through the annular groove between the first land portion 171 and the second land portion 172. When pilot pressure is conducted to the pilot chamber 21b and the spool 153 moves from the communication position (Y) to the right in Figures 5 and 6 to the block position (X), the second land portion 172 blocks communication between the first supply passage 261a and the second supply passage 262a.

[0040] Furthermore, the first land portion 171 connects or blocks communication between the adjacent first load pressure passage 162a and second load pressure passage 162b. When the spool 153 is in the connecting position (Y), as shown in Figures 5 and 6, the first load pressure passage 162a and the second load pressure passage 162b are connected via the annular groove between the first land portion 171 and the third land portion 173. When the spool 153 is in the blocking position (X), the first land portion 171 blocks communication between the first load pressure passage 162a and the second load pressure passage 162b.

[0041] As shown in Figure 7, the valve body 151 has a first check valve 51, a second check valve 52, and a check passage 55. The first check valve 51 and the second check valve 52 are provided on the other side surface 151e of the valve body 151, and are arranged parallel to each other and on the same plane (on the cross section shown in Figure 7). A relief port 167 that connects the check passage 55 and the relief passage 62 is opened and formed in the other side surface 151e of the valve body 151.

[0042] As shown in FIG. 8 , the valve body 151 has a first accommodating hole 231 and a second accommodating hole 232 in which the first unloading valve 31 and the second unloading valve 32 are accommodated, respectively. The first accommodating hole 231 and the second accommodating hole 232 open to one side surface 151d of the valve body 151 and are aligned parallel to each other and formed on the same plane (on the cross section shown in FIG. 8 ). In other words, the first unloading valve 31 and the second unloading valve 32 are accommodated in the first accommodating hole 231 and the second accommodating hole 232, respectively, so that their axes (specifically, spools 31a and 32a, described below) are parallel to each other, and are arranged side by side in the D1 direction and extending in the D2 direction. The D1 direction is the parallel direction in which the first unloading valve 31 and the second unloading valve 32 are aligned. Here, "parallel" refers to not only completely parallel, but also to a state in which they are not strictly parallel but are slightly tilted due to manufacturing errors or the like. The first accommodating hole 231 is connected to the first load pressure passage 162a, the main passage 261b of the first supply passage 261a, and the tank passage 122a, and the second accommodating hole 232 is connected to the second load pressure passage 162b, the main passage 262b of the second supply passage 262a, and the tank passage 122a.

[0043] A spool passage 31b communicating with the first load pressure passage 162a is formed in the spool 31a of the first unloading valve 31, and hydraulic oil from the first load pressure passage 162a is guided through the spool passage 31b, applying pressure to close the spool 31a together with the spring 31d. A spool passage 31c communicating with the main passage 261b of the first supply passage 261a is also formed in the spool 31a, and hydraulic oil from the main passage 261b is guided through the spool passage 31c, applying pressure to open the spool 31a. When the load due to the pressure in the spool passage 31c exceeds the combined load of the pressure in the spool passage 31b and the biasing force of the spring 31d, the first unloading valve 31 opens, and hydraulic oil is guided from the main passage 261b to the tank passage 122a through a notch (not shown) formed in the outer peripheral surface of the spool 31a, thereby unloading the hydraulic oil.

[0044] Similar to the spool 31a, the spool 32a of the second unloading valve 32 is formed with a spool passage 32b communicating with the second load pressure passage 162b and a spool passage 32c communicating with the main passage 262b of the second supply passage 262a. Hydraulic oil from the second load pressure passage 162b is guided through the spool passage 32b, and pressure acts to close the spool 32a together with the spring 32d. Hydraulic oil from the main passage 262b is guided through the spool passage 32c, and pressure acts to open the spool 32a. When the load due to the pressure in the spool passage 32c exceeds the total load of the pressure in the spool passage 32b and the biasing force of the spring 32d, the second unloading valve 32 opens, and hydraulic oil is guided from the main passage 262b to the tank passage 122a through a notch (not shown) formed in the outer peripheral surface of the spool 32a, thereby unloading the hydraulic oil.

[0045] In the present embodiment, as described above, the confluence control valve 21, the first unloading valve 31, and the second unloading valve 32 are all provided in the valve body 151 of the inlet block 100. Therefore, the dimension of the entire inlet block 100 in one direction (the parallel direction D1 in which the first unloading valve 31 and the second unloading valve 32 are lined up) can be made smaller than in a configuration in which the confluence control valve 21, the first unloading valve 31, and the second unloading valve 32 are each provided in a separate valve block and arranged side by side.

[0046] Furthermore, in this embodiment, as shown in FIG. 10 , the confluence control valve 21 (specifically, the spool 153) is provided at a distance from the first unloader valve 31 and the second unloader valve 32 in a vertical direction (D3 direction) perpendicular to the parallel arrangement direction (D1 direction) of the first unloader valve 31 and the second unloader valve 32 and their axial directions (D2 direction). In other words, the spool 153 is provided at a predetermined distance from the first unloader valve 31 and the second unloader valve 32 in the D3 direction without overlapping them. Therefore, the first unloader valve 31 and the second unloader valve 32 can be disposed close to each other in the D1 direction, thereby further reducing the dimension of the inlet block 100 in the D1 direction. Furthermore, the confluence control valve 21 (specifically, the spool 153) is provided between the first unloader valve 31 and the second unloader valve 32 in the D1 direction. In other words, the spool 153 is not positioned further outward from the valve body 151 in the direction D1 than the first unloading valve 31, and is not positioned further outward from the valve body 151 than the second unloading valve 32. This allows the dimension of the inlet block 100 in the direction D1 to be made smaller.

[0047] In addition, in this embodiment, the tank passage 122a is shared by the first unloading valve 31 and the second unloading valve 32, so the flow path configuration of the inlet block 100 can be simplified.

[0048] 2, 4, and 8, in the present embodiment, the first pump port 260a is formed so that a portion of the first unloading valve 31 overlaps on an extension line of the first pump port 260a in the vertical direction (direction D3), and the second pump port 260b is formed so that a portion of the second unloading valve 32 overlaps on an extension line of the first pump port 260a in the vertical direction. This allows the flow path from the first pump port 260a to the first unloading valve 31 and the flow path from the second pump port 260b to the second unloading valve 32 to be substantially linear, as described above, thereby simplifying the flow path configuration of the inlet block 100. Note that the first pump port 260a and the second pump port 260b may be formed so that the entire first unloading valve 31 and the entire second unloading valve 32 overlap on an extension line of the first pump port 260a and the second unloading valve 32, respectively, in the direction D3.

[0049] Furthermore, in this embodiment, as shown in FIG. 8 , both the first unloading valve 31 and the second unloading valve 32 are provided on one side surface 151d of the valve body 151, and therefore a dead space exists in the valve body 151 beside the first unloading valve 31 and the second unloading valve 32 (specifically, between the other side surface 151e in the direction D2 and the first unloading valve 31 and the second unloading valve 32). A pilot passage 270 provided in the valve device 10 is formed in this dead space. The pilot passage 270 receives hydraulic oil from the first supply passage 261a (first hydraulic circuit HC1) and guides pilot fluid to the control valve 110a (see FIG. 1 ) serving as an actuator control valve that controls the operation of the actuator MR. Note that the pilot passage 270 is not shown in FIG. 1 . The pilot passage 270 is, for example, a passage that guides primary pressure to a pressure reducing valve (not shown) that generates pilot pressure. A portion of the pilot passage 270 is formed in a region between the other side surface 151e of the valve body 151 opposite the one side surface 151d and the first unloading valve 31 and the second unloading valve 32. In other words, a portion of the pilot passage 270 is formed between the other side surface 151e and the first unloading valve 31 and the second unloading valve 32 in the direction D2. This makes it possible to effectively utilize the dead space of the valve body 151. Note that the entire pilot passage 270 may be formed in the dead space, or another passage, such as a drain passage of a pressure reducing valve, may be formed in the dead space. Furthermore, a pilot passage 270 that guides pilot fluid to control valves 110b, 120a, and 120b other than the control valve 110a may be formed in the dead space.

[0050] According to the above-described embodiment, the following advantageous effects are achieved.

[0051] In the inlet block 100, the confluence control valve 21, the first unloading valve 31, and the second unloading valve 32 are all provided in the valve body 151. Therefore, the dimension of the entire valve body 151 in the D1 direction can be made smaller than in a configuration in which the confluence control valve 21, the first unloading valve 31, and the second unloading valve 32 are each provided in separate valve bodies 151 and arranged side by side. Furthermore, the spool 153 is provided away from the first unloading valve 31 and the second unloading valve 32 in the D3 direction and is provided between the first unloading valve 31 and the second unloading valve 32 in the D1 direction, so the dimension of the valve body 151 in the D1 direction can be made even smaller.

[0052] The following modified examples are also within the scope of the present invention, and it is possible to combine the configuration shown in the modified example with the configuration described in the above embodiment, or to combine the configurations described in the different modified examples below.

[0053] <Modification 1> In the above embodiment, the first throttle 131, the second throttle 132, the first check valve 51, and the second check valve 52 are provided in the valve body 151 of the inlet block 100, but the present invention is not limited to this. The above components may be provided in a location other than the valve body 151. Furthermore, the relief valve 60 may be provided in the valve body 151.

[0054] <Modification 2> In the above embodiment, the configuration has been described in which hydraulic oil is supplied from the first pump 111 and the second pump 114 to the first hydraulic circuit HC1 and the second hydraulic circuit HC2, respectively. However, the present invention may also be configured in such a way that hydraulic oil is supplied to the first hydraulic circuit HC1 and the second hydraulic circuit HC2 from a single split-flow pump. In this configuration, the first pump 111 and the second pump 114 are provided within a single pump, and the single pump has two discharge ports.

[0055] In the above embodiment, an example in which the present invention is applied to the hydraulic system 1 of a hydraulic excavator has been described, but the present invention is not limited to this. The present invention can be applied to hydraulic systems of various types of work equipment, such as crawler cranes, wheel loaders, and forklifts.

[0056] The configuration, operation, and effects of the embodiment of the present invention will be described below.

[0057] The inlet block 100 includes a confluence control valve 21 that confluences or blocks the working fluid discharged from the first pump 111 through a first fluid pressure passage (first main supply passage 121a) and the working fluid discharged from the second pump 114 through a second fluid pressure passage (second main supply passage 121b), a first unloading valve 31 that is connected to the first fluid pressure passage and that unloads the working fluid discharged from the first pump 111, and a second unloading valve 32 that is connected to the second fluid pressure passage and that unloads the working fluid discharged from the second pump 114, and a first fluid pressure passage and a second fluid pressure passage are formed in the inlet block 100. and a valve body 151 in which a confluence control valve 21, a first unloading valve 31, and a second unloading valve 32 are provided, the first unloading valve 31 and the second unloading valve 32 being arranged side by side so that their axes are parallel to each other, and the confluence control valve 21 is provided apart from the first unloading valve 31 and the second unloading valve 32 in a vertical direction (D3) that is perpendicular to the parallel direction (D1) in which the first unloading valve 31 and the second unloading valve 32 are arranged and to the axial direction (D2) of both, and is provided between the first unloading valve 31 and the second unloading valve 32 in the parallel direction.

[0058] In this configuration, the confluence control valve 21, the first unloading valve 31, and the second unloading valve 32 are all provided in the valve body 151. Therefore, the dimension of the entire valve body 151 in one direction (the parallel direction in which the first unloading valve 31 and the second unloading valve 32 are lined up) can be made smaller than in a configuration in which the confluence control valve 21, the first unloading valve 31, and the second unloading valve 32 are each provided in a separate valve body 151 and arranged side by side. Furthermore, because the confluence control valve 21 is provided away from the first unloading valve 31 and the second unloading valve 32 in the vertical direction and is provided between the first unloading valve 31 and the second unloading valve 32 in the parallel direction, the dimension of the inlet block 100 in one direction (the parallel direction) can be made smaller.

[0059] The inlet block 100 also has two accommodating holes 231, 232 in which the first unloading valve 31 and the second unloading valve 32 are respectively accommodated, and a tank passage 122a formed between the two accommodating holes 231, 232 and communicating with the tank 112, and the working fluid unloaded by the first unloading valve 31 and the second unloading valve 32 is led to the tank passage 122a.

[0060] In this configuration, the tank passage 122a is shared by the first unloading valve 31 and the second unloading valve 32, so the flow path configuration of the inlet block 100 can be simplified.

[0061] Furthermore, in the inlet block 100, a first pump port 260a that communicates with the first pump 111 and leads the working fluid to the first fluid pressure passage, and a second pump port 260b that communicates with the second pump 114 and leads the working fluid to the second fluid pressure passage are formed and opened on the outer surface of the valve body 151, and the first pump port 260a is formed so that at least a portion of the first unloading valve 31 overlaps on its extension line in the vertical direction, and the second pump port 260b is formed so that at least a portion of the second unloading valve 32 overlaps on its extension line in the vertical direction.

[0062] In this configuration, the flow path from the first pump 111 port to the first unloading valve 31 and the flow path from the second pump 114 port to the second unloading valve 32 can be made approximately linear, thereby simplifying the flow path configuration of the inlet block 100.

[0063] In addition, in the valve device 10 which includes an inlet block 100, an actuator block which is connected to the inlet block 100 and has actuator control valves (control valves 110a, 110b, 120a, 120b) which are supplied with working fluid from a first fluid pressure passage (first main supply passage 121a) or a second fluid pressure passage (second main supply passage 121b) and which control the operation of the actuators (MR, AS, ML, BS), and a pilot passage 270 which guides pilot fluid to the actuator control valves, the first unloading valve 31 and the second unloading valve 32 are respectively housed in two housing holes 231, 232 which are formed and open to one end face of the valve body 151, and at least a part of the pilot passage 270 is formed in the region between the other end face opposite to the one end face of the valve body 151 and the first unloading valve 31 and the second unloading valve 32.

[0064] In this configuration, dead space exists in the valve body 151 next to the first unloading valve 31 and the second unloading valve 32. A pilot passage 270 is formed in this dead space, so the dead space in the inlet block 100 can be effectively utilized.

[0065] 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.

[0066] This application claims priority based on Japanese Patent Application No. 2024-36057, filed with the Japan Patent Office on March 8, 2024, the entire contents of which are incorporated herein by reference.

Claims

1. An inlet block comprising: a confluence control valve that confluences or blocks the flow of a working fluid discharged from a first pump through a first fluid pressure passage and a working fluid discharged from a second pump through a second fluid pressure passage; a first unloading valve connected to the first fluid pressure passage and unloading the working fluid discharged from the first pump; a second unloading valve connected to the second fluid pressure passage and unloading the working fluid discharged from the second pump; and a valve body in which the first fluid pressure passage and the second fluid pressure passage are formed and in which the confluence control valve, the first unloading valve, and the second unloading valve are provided, wherein the first unloading valve and the second unloading valve are arranged side by side with their axes parallel to each other, and the confluence control valve is arranged apart from the first unloading valve and the second unloading valve in a vertical direction that is perpendicular to the parallel direction in which the first unloading valve and the second unloading valve are arranged and to the axial direction of both, and is arranged between the first unloading valve and the second unloading valve in the parallel direction.

2. An inlet block as claimed in claim 1, wherein the valve body has two accommodation holes in which the first unloading valve and the second unloading valve are respectively accommodated, and a tank passage formed between the two accommodation holes and communicating with a tank, and the working fluid unloaded by the first unloading valve and the second unloading valve is led to the tank passage.

3. An inlet block as claimed in claim 1, wherein a first pump port communicating with the first pump and directing the working fluid to the first fluid pressure passage, and a second pump port communicating with the second pump and directing the working fluid to the second fluid pressure passage are formed and opened on the outer surface of the valve body, the first pump port being formed so that at least a portion of the first unloading valve overlaps on its extension in the vertical direction, and the second pump port being formed so that at least a portion of the second unloading valve overlaps on its extension in the vertical direction.

4. A valve device comprising: an inlet block as defined in claim 1; an actuator block connected to said inlet block and having an actuator control valve which receives working fluid from said first fluid pressure passage or said second fluid pressure passage and controls the operation of an actuator; and a pilot passage which introduces pilot fluid to said actuator control valve, wherein said first unloading valve and said second unloading valve are respectively housed in two housing holes which are formed and open to one end face of said valve body, and at least a part of said pilot passage is formed in the region between the other end face of said valve body opposite to said one end face and said first unloading valve and said second unloading valve.

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