Electromagnetic proportional valve, fluid system and construction machinery

Abstract

To provide an electromagnetic proportional valve that can simplify and miniaturize a structure for electrical control, and to provide a fluid system using the electromagnetic proportional valve, and a construction machine.SOLUTION: An electromagnetic proportional valve 150 includes: a valve part 10; and a drive device part 20 for driving the valve part 10 in accordance with a drive current. The drive device part 20 includes: a detection part 170 for detecting information relating to a state of at least one of the valve part 10 and the drive device part 20; and a control unit 200 for controlling the drive current on the basis of a detection result of the detection part 170.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to an electromagnetic proportional valve, a fluid system, and a construction machine. [Background technology]

[0002] An increasing number of hydraulic systems, for example hydraulic circuits in construction machines, are equipped with electrically controlled electromagnetic proportional valves. An electromagnetic proportional valve includes, for example, an electromagnetic coil (solenoid), a rod driven by the electromagnetic coil, a spool that moves when pressed by the rod, and a return spring that returns the spool to its original position. The spool blocks and connects each of the ports connected to a pilot flow path to which hydraulic oil is supplied from a hydraulic pump, a control port that adjusts the opening of hydraulic oil to the actuator to be driven, and a drain port that is connected to a tank that stores return oil. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Utility Model Application Publication No. 4-036183 Summary of the Invention [Problem to be solved by the invention]

[0004] It is necessary to detect the pressure of hydraulic oil in order to electrically control the solenoid proportional valve. For example, the solenoid proportional valve described in Patent Document 1 has a drain port, a control port, and a pilot port in a direction perpendicular to the moving direction of the spool. When detecting the pressure of the control port and the pilot port, the solenoid proportional valve having such a configuration needs to provide a pressure detection unit separately from the solenoid proportional valve. This leads to a complicated hydraulic circuit and a possibility that the complicated hydraulic circuit will become large in size.

[0005] The present invention provides an electromagnetic proportional valve that enables the structure for electrical control to be simplified and made compact, and a fluid system and construction machine that use this electromagnetic proportional valve. [Means for solving the problem]

[0006] An electromagnetic proportional valve according to one embodiment of the present invention comprises a valve section and a drive unit that drives the valve section in response to a drive current, the drive unit comprising a detection unit that detects information regarding the state of at least one of the valve section and the drive unit, and a control unit that controls the drive current based on the detection result of the detection unit.

[0007] In this way, by providing the detection unit and the control unit in the electromagnetic proportional valve itself, the electromagnetic proportional valve can be made smaller without creating extra space outside the electromagnetic proportional valve. In addition, the configuration of the entire fluid system can be simplified. The detection unit only needs to detect information necessary to control the electromagnetic proportional valve, such as the pressure of the working fluid, or the movement acceleration, distortion, temperature, etc. of the spool of the electromagnetic proportional valve, as information regarding the state of at least one of the valve unit and the drive unit.

[0008] In the above configuration, the valve portion may include a spool having a through hole along the axial direction through which working fluid from a pump port passes, the drive device portion may include an electric drive portion that drives the spool, and the control portion may perform drive control of the electric drive portion.

[0009] In the aforementioned configuration, the information may be a pressure of the working fluid passing through the through hole.

[0010] In the above configuration, the spool, the electric driving unit, the detection unit, and the control unit may be arranged in this order along the axial direction.

[0011] In the above configuration, the electric driving unit may include a case that houses a rod that pushes the spool, the detection unit, and the control unit, and the detection unit may detect the pressure of the working fluid at the pump port.

[0012] In the above configuration, the control unit may include a communication unit for transmitting and receiving data to and from another control unit.

[0013] According to another aspect of the present invention, a fluid system includes a fluid pump that discharges a working fluid, a control valve that switches the output destination of the working fluid, an actuator that is driven by the working fluid supplied from the control valve, and an electromagnetic proportional valve that applies a control pressure of the working fluid to the control valve, wherein the electromagnetic proportional valve includes a valve unit and a drive unit that drives the valve unit in response to a drive current, the valve unit including a spool having a through hole along the axial direction and through which the working fluid passes, the drive unit including a detection unit that detects information regarding a state of at least one of the valve unit and the drive unit, a control unit that controls the drive current based on the detection result of the detection unit, and an electric drive unit that drives the spool using the drive current, wherein the electric drive unit includes a case that houses a rod that pushes the spool, the detection unit, and the control unit, and the detection unit detects the control pressure.

[0014] With this configuration, the proportional solenoid valve can be made smaller without creating extra space outside the valve, and the configuration of the entire fluid system can be simplified.

[0015] According to another aspect of the present invention, a fluid system includes a fluid pump that discharges a working fluid, a control valve that switches the output destination of the working fluid, an actuator that is driven by the working fluid supplied from the control valve, and an electromagnetic proportional valve that applies a control pressure of the working fluid to the control valve, wherein the electromagnetic proportional valve includes a valve unit and a drive unit that drives the valve unit in response to a drive current, the valve unit including a spool having a through hole along the axial direction and through which the working fluid passes, the drive unit including a detection unit that detects information regarding a state of at least one of the valve unit and the drive unit, a control unit that controls the drive current based on the detection result of the detection unit, and an electric drive unit that drives the spool using the drive current, wherein the electric drive unit includes a case that houses a rod that pushes the spool, the detection unit, and the control unit, and the detection unit detects the control pressure.

[0016] With this configuration, the solenoid proportional valve can be controlled based on the control pressure in addition to the pressure of the working fluid at the pump port.

[0017] A construction machine according to another aspect of the present invention comprises a fluid system and a vehicle body on which the fluid system is mounted, the fluid system comprising a fluid pump that discharges a working fluid, a control valve that switches the output destination of the working fluid, an actuator that is driven by the working fluid supplied from the control valve, and an electromagnetic proportional valve that applies a control pressure of the working fluid to the control valve, the electromagnetic proportional valve comprising a valve unit and a drive unit that drives the valve unit in response to a drive current, the valve unit comprising a spool having a through hole along the axial direction and through which working fluid from a pump port passes, the drive unit comprising a detection unit that detects information regarding the state of at least one of the valve unit and the drive unit, a control unit that controls the drive current based on the detection result of the detection unit, and an electric drive unit that drives the spool with the drive current, the electric drive unit comprising a case that houses a rod that pushes the spool, the detection unit, and the control unit, and the detection unit detects the pressure of the working fluid at the pump port.

[0018] With this configuration, the control pressure of the working fluid by the electromagnetic proportional valve can be controlled with high precision, making it possible to provide a construction machine with excellent operability. Effect of the Invention

[0019] According to the present invention, the structures for electrically controlling the electromagnetic proportional valve, the fluid system, and the construction machine can be simplified and made compact. [Brief description of the drawings]

[0020] [Figure 1] 1 is a schematic configuration diagram of a construction machine according to an embodiment of the present invention. [Diagram 2] FIG. 1 is a configuration diagram of a hydraulic system according to an embodiment of the present invention. [Diagram 3]1 is a schematic configuration diagram of an electromagnetic proportional valve according to an embodiment of the present invention. FIG. [Figure 4] 5 is an explanatory diagram of the operation of the solenoid proportional valve according to the embodiment of the present invention. FIG. [Diagram 5] FIG. 13 is a schematic configuration diagram of a hydraulic system according to a modified example of the embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0021] Next, an embodiment of the present invention will be described with reference to the drawings.

[0022] <Construction machinery> FIG. 1 is a schematic configuration diagram of a construction machine 100. 1, the construction machine 100 is, for example, a hydraulic excavator. The construction machine 100 includes a revolving body (an example of a vehicle body in the claims) 101, a running body (an example of a vehicle body in the claims) 102 provided below the revolving body 101, and a hydraulic system (an example of a fluid system in the claims) 1.

[0023] The rotating body 101 rotates above the traveling body 102. The rotating body 101 includes a cab 103 on which an operator can ride, a boom 104 having one end swingably connected to the rotating body 101, an arm 105 having one end swingably connected to the other end (tip) of the boom 104, a bucket 106 swingably connected to the other end (tip) of the arm 105, and an operation unit 108 operated by the operator. The rotating body 101, the boom 104, the arm 105, and the bucket 106 are driven by hydraulic oil (an example of the working fluid in the claims) supplied from the hydraulic system 1.

[0024] <Hydraulic system> FIG. 2 is a configuration diagram of the hydraulic system 1. As shown in FIG. 2, the hydraulic system 1 includes an engine 120 as a driving source, a hydraulic pump (an example of a fluid pump in the claims) 130 driven by the engine 120, a plurality of actuators 140 that operate various parts of the construction machine 100, a control valve 500 that switches the operation of the plurality of actuators 140, an electromagnetic proportional valve 150 that applies a control pressure of hydraulic oil to the control valve 500, a tank 160 that stores the hydraulic oil, and a relief valve 300 for adjusting the pressure.

[0025] The engine 120 is an internal combustion engine that uses gasoline or diesel fuel. The engine 120 is provided with an output shaft 121. The output shaft 121 is connected to a hydraulic pump . A pipe Q is connected to the hydraulic pump 130. The hydraulic pump 130 is driven by the output shaft 121 to discharge hydraulic oil to the pipe Q. A control valve 500 and an electromagnetic proportional valve 150 are connected to the pipe Q.

[0026] In this embodiment, the engine 120 is used as the driving source of the hydraulic oil, but the driving source may be an electric motor that uses a power source device such as a storage battery as a power source other than the engine 120. Also, the engine 120 may be used together with a generator that charges the storage battery or is used as a power source.

[0027] A plurality of actuators 140 are connected to the control valve 500 via a branched pipe Q. A plurality of control valves 500 are provided, and the hydraulic pressure of the hydraulic oil flowing through the pipe Q is switched by a plurality of spools in response to a switching operation of the operation unit 108, to supply the hydraulic oil to the plurality of actuators 140. The plurality of actuators 140 include hydraulic cylinders that drive the boom 104, the arm 105, the bucket 106, etc., a hydraulic motor that drives the rotating body 101, etc.

[0028] The relief valve 300 releases the pressure when the pressure of the hydraulic oil in the hydraulic circuit (in the pipe Q) of the hydraulic system 1 reaches or exceeds a preset value. The solenoid proportional valve 150 moves a spool with the hydraulic pressure of the hydraulic oil from a pilot pump (not shown) based on the operation amount of the operation unit 108, and supplies the hydraulic oil from the hydraulic pump 130 to the actuator 140. The solenoid proportional valve 150 will be described in detail below.

[0029] <Solenoid proportional valve> FIG. 3 is a schematic diagram of the proportional solenoid valve 150. As shown in FIG. 3, the electromagnetic proportional valve 150 controls the valve opening to move a spool of a control valve 500 and adjust the flow rate of hydraulic oil from the hydraulic pump 130 to the actuator 140. The electromagnetic proportional valve 150 includes a valve unit 10 for applying a control pressure of the hydraulic oil to the control valve 500, and a drive unit 20 for driving the valve unit 10 in response to a drive current. The drive unit 20 includes a detection unit 170 that detects information regarding the state of the electromagnetic proportional valve 150, a control unit 200 that generates a control signal (controls the drive current) based on the detection result of the detection unit 170 and the operation amount of the operation unit 108, and an electric drive unit 151 that drives the valve unit 10 based on the control signal generated by the control unit 200.

[0030] The detection unit 170 detects, for example, the pilot pressure of the hydraulic oil flowing through a pump port RP connected to the valve unit 10, as described below, as information on the state of the valve unit 10. The detection value detected by the detection unit 170 is fed back to the control unit 200.

[0031] The electric driving unit 151 includes, for example, an electromagnetic coil 152 (solenoid) serving as a driving source, a rod 153 driven by the electromagnetic coil 152, and a case 154 serving as an exterior. The case 154 is formed so as to cover an opening of a spool hole H, which will be described later, formed in the valve unit 10. The electromagnetic coil 152 (electric driving unit 151), the detection unit 170, and the control unit 200 are arranged and stored in this order from the valve unit 10 side inside the case 154. In addition, a partition wall 149 is provided inside the case 154, which divides the inside of the case 154 into a first room K1 in which the electric driving unit 151 and the detection unit 170 are arranged, and a second room K2 in which the control unit 200 is arranged.

[0032] The electromagnetic coil 152 is formed in a cylindrical shape by winding a copper wire around an iron core. The electromagnetic coil 152 generates a magnetic field by passing a current through the copper wire.

[0033] The rod 153 is made of metal and formed into a rod shape. The rod 153 is also called a plunger. The axial direction of the rod 153 and the axial direction of the electromagnetic coil 152 coincide with each other. The rod 153 is disposed within the electromagnetic coil 152 so as to be movable in the axial direction. One end 153A of the rod 153 on the valve portion 10 side abuts against the other end S2 of a spool S of the valve portion 10, which will be described later.

[0034] A protruding portion 153T protruding radially outward is formed on the outer circumferential surface of the rod 153. A magnetic field of the electromagnetic coil 152 is applied to this protruding portion 153T. The protruding portion 153T of the rod 153 is disposed slightly offset from the neutral axis L of the electromagnetic coil 152 toward the other end 153B of the rod 153. Therefore, when the electromagnetic coil 152 is energized, the protruding portion 153T (rod 153) is attracted by the magnetic field generated by the electromagnetic coil 152 and moves in the direction of the neutral axis L of the electromagnetic coil 152 (toward the valve portion 10). As a result, the rod 153 pushes the spool S of the valve portion 10, which will be described later.

[0035] The amount of current supplied to the electromagnetic coil 152 is proportionally controlled according to the amount of operation of the operation unit 108, and is also controlled based on a detection value detected by the detection unit 170. As a result, the amount of protrusion of the rod 153 is adjusted by the electromagnetic coil 152. The details of the effect of adjusting the amount of protrusion of the rod 153 will be described later.

[0036] The valve section 10 includes, for example, a cylindrical valve body 155 accommodated in a valve accommodating hole 12 formed in a casing 11 of a control valve 500 constituting the hydraulic system 1, a flange portion 13 provided on the drive unit section 20 side of the valve body 155, a spool S movably accommodated in a spool hole H formed in the valve body 155, and a return spring G that returns the moved spool S to its original position.

[0037] A pump port RP is provided in the casing 11, to which a pipe Q is connected and into which hydraulic oil flows from a pilot pump (gear pump) (not shown). The pilot pump and the hydraulic pump 130 are connected in tandem to an output shaft 121 of the engine 120, and the pilot pump is also driven by the output shaft 121. The casing 11 is provided with a drain port RD connected to a flow path leading to the tank 160, and a control port RA connected to a flow path leading to a spool of the control valve 500. Note that "communicating" (making it communicate, passing through) refers to allowing hydraulic oil (i.e., fluid) to flow. For example, "a flow path leading to the tank 160" refers to a flow path configured to allow hydraulic oil to flow between that flow path and the tank 160.

[0038] The spool hole H of the valve body 155 penetrates the valve body 155 in the axial direction. The spool hole H is arranged in the order of a first through hole H1, a second through hole H2, a third through hole H3, and a fourth through hole H4 from one end 155A of the valve body 155 opposite to the drive unit 20. The inner diameter of the second through hole H2 is larger than the inner diameter of the first through hole H1. The inner diameter of the third through hole H3 is larger than the inner diameter of the second through hole H2. The inner diameter of the fourth through hole H4 is larger than the inner diameter of the third through hole H3.

[0039] A return spring G is disposed in the second through hole H2. The return spring G is an elastic member such as a coil spring. One end GA of the return spring G on the first through hole H1 side is in contact with a step surface between the first through hole H1 and the second through hole H2. This restricts the movement of the return spring G toward the first through hole H1 side.

[0040] The first through hole H1 communicates with the pump port RP. The valve body 155 is formed with an actuator communication hole 156 that radially communicates the third through hole H3 with the control port RA. The valve body 155 is also formed with a drain communication hole 157 that radially communicates the fourth through hole H4 with the drain port RD. A plurality of seal members 158 are provided on the outer circumferential surface of the valve body 155, i.e., between the valve body 155 and the casing 11, to prevent the first through-hole H1, the actuator communication hole 156, and the drain communication hole 157 from communicating with each other on the outer circumferential surface side of the valve body 155. An example of the seal members 158 is an O-ring.

[0041] The flange portion 13 connects the valve body 155 and the drive unit 20, and also serves to attach the solenoid proportional valve 150 to the casing 11. A seal member 159 is provided between the flange portion 13 and the casing 11. An example of the seal member 159 is an O-ring. The seal member 159 ensures sealing between the flange portion 13 and the casing 11. The flange portion 13 is provided so as to close the opening on the drive unit 20 side of the fourth through hole H4 formed in the valve body 155. A through hole 13A is formed in the radial center of the flange portion 13, through which one end 153A of the rod 153 constituting the drive unit 20 is passed.

[0042] A disk-shaped support block 14 is provided on the inner surface of the flange portion 13 on the valve body 155 side. The support block 14 defines a fourth through hole H4. A through hole 14A that communicates with the through hole 13A is formed in the radial center of the support block 14. The through hole 14A supports the other end S2 of the spool S on the drive unit 20 side so as to be freely movable in the axial direction. As a result, one end 153A of a rod 153 constituting the drive unit 20 abuts against the other end S2 of the spool S via the through hole 14A.

[0043] The spool S is formed, for example, from metal in a rod shape. One end S1 of the spool S opposite to the drive unit 20 is supported in the second through hole H2 of the valve body 155 so as to be freely movable. The other end GB of the return spring G disposed in the second through hole H2 of the valve body 155 is in contact with one end S1 of the spool S. The return spring G is disposed in a compressed state by this one end S1 and a step surface between the first through hole H1 and the second through hole H2 in the valve body 155. The restoring force of the return spring G constantly presses the spool S toward the drive unit 20.

[0044] A through hole SH is formed in the spool S along the axial direction. The through hole SH communicates with the pump port RP via a first through hole H1 of the valve body 155. A protrusion S3 having a diameter larger than both ends S1, S2 of the spool S is formed in most of the axial center of the spool S. The protrusion S3 is inserted into a third through hole H3 of the valve body 155 so as to be freely movable in the axial direction.

[0045] The protruding portion S3 has a step S4 on the other end S2 side. The step S4 is located inside the fourth through hole H4. The pressure of the drain port RD acts on the step S4. The protruding portion S3 has a step S5 on the one end S1 side. The step S5 is located inside the third through hole H3. The pressure of the control port RA acts on the step S5. Furthermore, the protrusion S3 is formed with a groove-like notch SN (first flow passage) extending along the axial direction. The notch SN forms a closed end SN1 on the step S4 side that does not lead to the step S4. The notch SN also forms an open end SN2 on the step S5 side that leads to the step S5.

[0046] Three second flow paths S6 communicating with the through holes SH are formed in the protruding portion S3. The second flow paths S6 are formed in a direction perpendicular to the through holes SH. The three second flow paths S6 are disposed at equal intervals in the circumferential direction at positions avoiding the notches SN.

[0047] <Operation of solenoid proportional valve> Next, the operation of the proportional solenoid valve 150 will be described. First, as shown in FIG. 3, when the electric drive unit 151 is not driven, the spool S is in a neutral position (original position) due to the restoring force of the return spring G. In the neutral position of the spool S, the third through hole H3 and the fourth through hole H4 are communicated by the spool S. That is, the closed end SN1 of the notch SN is positioned in the fourth through hole H4. The open end SN2 is positioned in the third through hole H3. This allows the notch SN to communicate between the third through hole H3 and the fourth through hole H4. As a result, in the neutral position of the spool S, the notch SN allows the drain port RD and the control port RA to communicate with each other.

[0048] In addition, when the spool S is in the neutral position, the third through hole H3 and the first through hole H1 are blocked by the spool S. That is, the second flow passage S6 is housed in the third through hole H3, and the opening of the second flow passage S6 is blocked by the inner peripheral surface of the third through hole H3. In addition, since one end S1 of the spool S is inserted into the second through hole H2, the third through hole H3 and the first through hole H1 are partitioned by the one end S1 of the spool S. As a result, when the spool S is in the neutral position, the drain port RD and the control port RA are blocked from the pump port RP.

[0049] The hydraulic oil flowing in from the pump port RP flows into the through hole SH via the first through hole H1 and fills the first chamber K1 in the case 154 of the electric drive unit 151 from the other end S2 of the spool S, generating hydraulic pressure. The detection unit 170 detects the pressure (pilot pressure) of the hydraulic oil in the first chamber K1 in the case 154. Note that a partition wall 149 is provided in the case 154 to divide the inside of the case 154 into the first chamber K1 in which the electric drive unit 151 and the detection unit 170 are arranged and a second chamber K2 in which the control unit 200 is arranged. This prevents the hydraulic oil from filling the second chamber K2 in which the control unit 200 is arranged.

[0050] Next, a case where the rod 153 is driven by the electric drive unit 151 will be described with reference to FIG. FIG. 4 is a diagram illustrating the operation of the proportional solenoid valve 150, and corresponds to the above-mentioned FIG. As shown in FIG. 4, when the electromagnetic coil 152 of the electric drive unit 151 is energized, the rod 153 is moved toward the valve unit 10. Then, the rod 153 pushes the spool S toward the opposite side to the drive unit 20. The spool S moves in a direction to compress and deform the return spring G. At this time, the size of the opening of the second flow passage S6 that communicates with the third through hole H3 increases according to the amount of movement of the spool S. As a result, the pump port RP and the third through hole H3 communicate with each other via the first through hole H1, the through hole SH, and the second flow passage S6. As a result, the spool S communicates the pump port RP with the control port RA and adjusts the flow rate of the hydraulic oil flowing to the control port RA.

[0051] At this time, the hydraulic oil flowing in from the pump port RP flows from the pump port RP through the first through hole H1, the second flow passage S6, and the third through hole H3 to the control port RA. The detection unit 170 detects the pressure of the hydraulic oil in the first chamber K1 in the case 154. When the movement of the spool S is completed, the closed end SN1 of the notch SN is housed in the third through hole H3. Therefore, the third through hole H3 and the fourth through hole H4 are blocked. That is, the spool S blocks the drain port RD and the control port RA.

[0052] In addition, In the above spool S state, It is also possible for the detection unit 170 to detect as follows. That is, The detection unit 170 detects the force transmitted from the other end S2 of the spool S to the rod 153. The pressure of the hydraulic oil supplied from the pump port RP acts on one end S1 of the spool S. Therefore, the detection unit 170 in the case 154 can directly detect the pressure (pilot pressure) of the pump port RP in accordance with the amount of movement of the spool S.

[0053] Based on the detection value detected by the detection unit 170, the control unit 200 generates a control signal, and based on this control signal, performs drive control of the electric drive unit 151. This makes it possible to appropriately adjust the flow rate of the hydraulic oil flowing through the control port RA. The control valve 500 is driven by the hydraulic oil flowing through the control port RA. In other words, adjusting the flow rate of the hydraulic oil flowing to the control port RA means adjusting the control pressure of the hydraulic oil for controlling the drive of the control valve 500. The control unit 200 controls the control pressure of the hydraulic oil to the control valve 500.

[0054] In this manner, the flow rate of the hydraulic oil supplied to a desired actuator 140 is adjusted by the electromagnetic proportional valve 150. Each actuator 140 is driven by the hydraulic oil supplied via the control valve 500.

[0055] As described above, the above-mentioned solenoid proportional valve 150 includes the detection unit 170 and the control unit 200. By providing the detection unit 170 and the control unit 200 in the solenoid proportional valve 150 itself, the solenoid proportional valve 150 can be made smaller without creating extra space outside the solenoid proportional valve 150. In addition, the configuration of the hydraulic system 1 as a whole can be simplified.

[0056] The control unit 200 controls the driving of the electric driving unit 151 for driving the spool S (valve unit 10). In the electromagnetic proportional valve 150, a pump port RP is connected to a through hole SH formed in the spool S, and the detection unit 170 detects the force applied to the rod 153 abutting against the spool S, thereby easily detecting the pressure (pilot pressure) of the hydraulic oil flowing through the pump port RP in accordance with the amount of movement of the spool S. That is, according to the electromagnetic proportional valve 150, the detection unit 170 detects the pressure applied to the spool S to which the pump port RP is connected in the direction of movement, so that the device configuration for detecting the pilot pressure can be simplified.

[0057] The electromagnetic coil 152 (electrical driving unit 151), the detection unit 170, and the control unit 200 are arranged and stored in this order from the valve unit 10 side within the case 154 of the electric driving unit 151. This allows the driving device unit 20 to be made as small as possible, and each unit constituting the driving device unit 20 can be easily integrated. Furthermore, hydraulic oil flows into case 154 through through hole SH of spool S. Since detection unit 170 is disposed adjacent to electromagnetic coil 152 (electrical drive unit 151), the path through which hydraulic oil reaches detection unit 170 is not unnecessarily long, reducing hysteresis and improving the responsiveness of detection unit 170. Furthermore, detection unit 170 has a simple structure and can easily detect the pressure of hydraulic oil flowing through pump port RP.

[0058] Furthermore, the construction machine 100 equipped with the hydraulic system 1 as described above can control the control pressure of the hydraulic oil by the electromagnetic proportional valve 150 with high precision, thereby improving operability.

[0059] [Variations] The present invention is not limited to the above-described embodiment, and includes various modifications to the above-described embodiment without departing from the spirit of the present invention. For example, in the above embodiment, a case where hydraulic oil is used as the working fluid and the hydraulic system 1 is applied as the fluid system has been described. However, this is not limited thereto, and the working fluid may be other than hydraulic oil. The configuration of the electromagnetic proportional valve 150 described above can be adopted in various fluid systems according to the type of working fluid. Even in the case of the hydraulic system 1, the hydraulic system 1 may be applied not only to construction machinery but also to other devices that use a working fluid, such as a hydraulic press.

[0060] In the above embodiment, the detection unit 170 detects the pilot pressure of the hydraulic oil flowing through the pump port RP as the information on the state of the valve unit 10. However, the present invention is not limited to this, and the detection unit 170 only needs to detect information on the state of at least one of the valve unit 10 and the drive unit 20 required to control the solenoid proportional valve 150. For example, the detection unit 170 may detect the position of the spool S, the movement acceleration of the spool S, the distortion of the spool S, the temperature of the spool S, the control pressure of the hydraulic oil for controlling the drive of the control valve 500, etc. as the information on the state of the valve unit 10.

[0061] Furthermore, instead of detecting the pilot pressure of the hydraulic oil flowing through the pump port RP as information regarding the state of the valve unit 10, the detection unit 170 may detect the pressure of the hydraulic oil passing through a through hole SH formed in the spool S. This is because the hydraulic oil flowing in from the pump port RP flows into the through hole SH via the first through hole H1 and fills the first chamber K1 in the case 154 of the electric drive unit 151 from the other end S2 of the spool S, generating hydraulic pressure. Therefore, detecting the pressure of the hydraulic oil passing through the through hole SH is equivalent to detecting the pilot pressure of the hydraulic oil flowing through the pump port RP.

[0062] The temperature of the hydraulic oil may also be used as information on the state of the valve section 10 and the drive unit 20. For example, the temperature of the hydraulic oil in the spool S is information on the state of the valve section 10, and the temperature of the hydraulic oil in the case 154 is information on the state of the drive unit 20. The temperature of any part of the drive unit 20 is information on the state of the drive unit 20. Specific examples of the temperature of any part of the drive unit 20 include the temperature of hydraulic oil in the electric drive unit 151, the temperatures of the electromagnetic coil 152 and rod 153 constituting the electric drive unit 151, and the temperature of the case 154 itself. In addition, the detection unit 170 may detect the position of the rod 153, the moving speed of the rod 153, etc. as information on the state of the drive unit 20.

[0063] In the above embodiment, the control unit 200 controls the driving of the electric driving unit 151. However, this is not limited to this, and the control unit 200 may include a communication unit 30 (see FIG. 5). An example of the communication unit 30 will be described below.

[0064] FIG. 5 is a schematic diagram showing a modified example of the hydraulic system 1. As shown in FIG. As shown in Fig. 5, the hydraulic system 1 may be configured to drive and control a plurality of electromagnetic proportional valves 150 by an integrated controller (an example of another control unit in the claims) 40. A communication unit 30 provided in the control unit 200 of each electromagnetic proportional valve 150 communicates with the integrated controller 40. This allows the integrated controller 40 to control each electromagnetic proportional valve 150 in an integrated manner. Furthermore, by providing the communication unit 30 in the control unit 200 in advance, the integrated controller 40 and the electromagnetic proportional valves 150 can communicate with each other without making major improvements to the integrated controller 40. This allows a user-friendly hydraulic system 1 to be provided.

[0065] In the above embodiment, the electromagnetic proportional valve 150 is used to apply the control pressure of the hydraulic oil to the control valve 500. However, this is not limited to this, and the configuration of the electromagnetic proportional valve 150 can be adopted to various configurations of electromagnetic proportional valves for controlling the control pressure of the hydraulic oil to fluid equipment (hydraulic equipment).

[0066] In the above embodiment, the spool hole H of the valve body 155 is arranged in this order from the end 155A of the valve body 155 opposite to the drive unit 20. The first through hole H1 is connected to the pump port RP. The valve body 155 has an actuator communication hole 156 that connects the third through hole H3 and the control port RA in the radial direction. However, this is not limited to this, and the pump port RP and the control port RA may be configured in reverse. That is, the first through hole H1 may be connected to the control port RA, and the third through hole H3 may be connected to the pump port RP in the radial direction. In this case, the detection unit 170 detects, for example, the pressure of the hydraulic oil flowing through the control port RA. Even in this configuration, the same effects as those of the above embodiment are achieved. Furthermore, the solenoid proportional valve can be controlled based on the control pressure to the control valve 500 in addition to the pilot pressure of the hydraulic oil flowing through the pump port RP. [Explanation of symbols]

[0067] 1...hydraulic system (fluid system), 10...valve section, 20...drive device section, 30...communication section, 40...integrated controller (other control section), 100...construction machine, 101...rotating body (vehicle body), 102...traveling body (vehicle body), 130...hydraulic pump (fluid pump), 140...actuator, 150...electromagnetic proportional valve, 151...electric drive section, 153...rod, 154...case, 170...detection section, 200...control section, 500...control valve, RA...control port, RD...drain port, RP...pump port, S...spool, S1...one end, S2...other end, SH...through hole

Claims

1. A pump port is provided in a casing having a valve receiving hole communicating with the pump port; a valve unit provided in the casing and a drive unit that drives the valve unit in response to a drive current; Equipped with The valve portion is A cylindrical valve body accommodated in the valve accommodation hole; a spool movably accommodated in a spool hole formed in the valve body along the axial direction; a return spring that is accommodated in the spool hole and elastically pushes the spool toward an opposite side to the pump port; Equipped with The spool has a through hole along an axial direction through which the working fluid from the pump port passes, the drive unit is provided at one end of the valve unit opposite to the pump port in the axial direction, The drive unit includes: a detection unit that detects a pressure of the working fluid passing through the through hole; a control unit that controls the drive current based on a detection result of the detection unit; an electric drive for driving the spool; Equipped with the electric drive unit includes a case provided at the one end of the valve unit, the case accommodates within the same space a rod that pushes the spool from the opposite side to the pump port, the detection unit, and the control unit; The same space communicates with the through hole, the detection unit detects a pressure of the working fluid leaking from the pump port through the through hole between the spool and the rod and filling the case, The control unit controls the driving of the electric drive unit. Solenoid proportional valve.

2. The spool, the electric driving unit, the detection unit, and the control unit are arranged in this order along the axial direction.

2. The proportional solenoid valve according to claim 1.

3. The solenoid proportional valve according to claim 1 or 2, wherein the control unit includes a communication unit for transmitting and receiving information to and from another control unit.

4. A fluid pump that discharges a working fluid; A control valve that switches an output destination of the working fluid; an actuator driven by the working fluid supplied from the control valve; an electromagnetic proportional valve that applies a control pressure of the working fluid to the control valve, The solenoid proportional valve is a casing provided with a pump port and having a valve receiving hole communicating with the pump port; a valve unit provided in the casing and a drive unit that drives the valve unit in response to a drive current; Equipped with The valve portion is A cylindrical valve body accommodated in the valve accommodation hole; a spool movably accommodated in a spool hole formed in the valve body along the axial direction; a return spring that is accommodated in the spool hole and elastically pushes the spool toward an opposite side to the pump port; Equipped with The spool has a through hole along an axial direction through which the working fluid from the pump port passes, the drive unit is provided at one end of the valve unit opposite to the pump port in the axial direction, The drive unit includes: A detection unit that detects a pressure of the working fluid passing through the through hole; a control unit that controls the drive current based on a detection result of the detection unit; an electric drive for driving the spool; Equipped with the electric drive unit includes a case provided at the one end of the valve unit, the case accommodates within the same space a rod that pushes the spool from the opposite side to the pump port, the detection unit, and the control unit; The same space and the through hole are in communication with each other, The detection unit detects the pressure of the working fluid leaking from the pump port through the through hole between the spool and the rod and filling the case. Fluid systems.

5. A fluid system; A vehicle body on which the fluid system is mounted; Equipped with The fluid system comprises: A fluid pump that discharges a working fluid; a control valve that switches an output destination of the working fluid; an actuator driven by the working fluid supplied from the control valve; an electromagnetic proportional valve that applies a control pressure of the working fluid to the control valve; Equipped with The solenoid proportional valve is a casing provided with a pump port and having a valve receiving hole communicating with the pump port; a valve unit provided in the casing and a drive unit that drives the valve unit in response to a drive current; Equipped with The valve portion is A cylindrical valve body accommodated in the valve accommodation hole; a spool movably accommodated in a spool hole formed in the valve body along the axial direction; a return spring that is accommodated in the spool hole and elastically pushes the spool toward an opposite side to the pump port; Equipped with The spool has a through hole along an axial direction through which the working fluid from the pump port passes, the drive unit is provided at one end of the valve unit opposite to the pump port in the axial direction, The drive unit includes: A detection unit that detects a pressure of the working fluid passing through the through hole; a control unit that controls the drive current based on a detection result of the detection unit; an electric drive for driving the spool; Equipped with the electric drive unit includes a case provided at the one end of the valve unit, the case accommodates within the same space a rod that pushes the spool from the opposite side to the pump port, the detection unit, and the control unit; The same space and the through hole are in communication with each other, The detection unit detects the pressure of the working fluid leaking from the pump port through the through hole between the spool and the rod and filling the case. Construction machinery.

Images