Electromagnetic proportional valve, fluid system, and construction machine

Abstract

Provided is an electromagnetic proportional valve, a fluid system, and a construction machine. An electromagnetic proportional valve (150) includes a valve portion (10) and a drive device portion (20) that drives the valve portion (10) in accordance with a drive current. The drive device portion (20) includes a detection portion (170) that detects information related to a state of at least either one of the valve portion (10) and the drive device portion (20), and a control portion (200) that controls the drive current based on a detection result of the detection portion (170).

Description

Technical Field

[0001] This invention relates to an electromagnetic proportional valve, a fluid system, and construction machinery. Background Technology

[0002] Fluid systems, such as the hydraulic circuits of construction machinery, are increasingly using electrically controlled electromagnetic proportional valves. These valves typically include: an electromagnetic coil (solenoid); a rod driven by the coil; a spool that is pushed by the rod; and a return spring that returns the spool to its original position. The spool connects and blocks ports connected to a pilot flow path supplied with working oil from a hydraulic pump, a control port that adjusts the opening of the working oil flowing to the actuator that is driven, and a discharge port connected to a reservoir for storing return oil.

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent Document 1: Japanese Utility Model Application Publication No. 4-036183 Summary of the Invention

[0006] The problem the invention aims to solve

[0007] To electrically control an electromagnetic proportional valve, it is necessary to detect the pressure of the working oil. For example, the electromagnetic proportional valve described in Patent Document 1 has a discharge port, a control port, and a pilot port arranged in a direction orthogonal to the movement direction of the spool. For electromagnetic proportional valves with such a structure, when detecting the pressure at the control port and pilot port, the pressure detection unit needs to be separately installed from the electromagnetic proportional valve. Therefore, the hydraulic circuit becomes more complex, and there is a possibility that the complex hydraulic circuit will be larger.

[0008] The present invention provides an electromagnetic proportional valve that simplifies the structure of electrical control and can be miniaturized, and a fluid system and construction machinery using the electromagnetic proportional valve.

[0009] Solution for solving the problem

[0010] An embodiment of the electromagnetic proportional valve of the present invention includes: a valve section; and a drive unit section that drives the valve section according to a drive current, the drive unit section including: a detection unit that detects information related to the state of at least one of the valve section and the drive unit section; and a control unit that controls the drive current based on the detection result of the detection unit.

[0011] Thus, by incorporating both a detection unit and a control unit within the electromagnetic proportional valve itself, unnecessary space is eliminated outside the valve, enabling its miniaturization. Furthermore, the overall structure of the fluid system can be simplified. The detection unit can detect, for example, the pressure of the working fluid, or the acceleration, strain, and temperature of the valve's spool, to obtain the information needed to control the electromagnetic proportional valve. This information relates to the state of at least one of the valve section and the drive unit.

[0012] In the above structure, the valve part may also include a spool valve core with a through hole along the axial direction, through which working fluid from the pump port flows, and the drive unit may include an electrical drive unit for driving the spool valve core, and the control unit may perform drive control of the electrical drive unit.

[0013] In the above structure, the information may also be the pressure of the working fluid flowing in the through hole.

[0014] In the above structure, the valve core, the electrical drive unit, the detection unit, and the control unit may also be arranged along the axial direction in the order of the valve core, the electrical drive unit, the detection unit, and the control unit.

[0015] In the above structure, the electrical drive unit may also include a housing that houses the rod for pushing the valve core, the detection unit, and the control unit, wherein the detection unit detects the pressure of the working fluid at the pump port.

[0016] In the above structure, the control unit may also have a communication unit that transmits and receives information relative to other control units.

[0017] Another aspect of the fluid system of the present invention includes: a fluid pump that ejects a working fluid; a control valve that switches the output of the working fluid; an actuator driven by the working fluid supplied from the control valve; and an electromagnetic proportional valve that causes a control pressure of the working fluid to act on the control valve. The electromagnetic proportional valve includes: a valve section; and a drive unit that drives the valve section according to a drive current. The valve section includes a spool having an axially extending through-hole through which working fluid from a pump port communicating with the fluid pump flows. The drive unit includes: a detection unit that detects information relating to the state of at least one of the valve section 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. The electric drive unit includes a housing housing a rod for pressing the spool, the detection unit, and the control unit. The detection unit detects the pressure of the working fluid at the pump port.

[0018] This design eliminates the need for extra space outside the electromagnetic proportional valve, allowing for its miniaturization. Furthermore, it simplifies the overall structure of the fluid system.

[0019] Another aspect of the fluid system of the present invention includes: a fluid pump that ejects a working fluid; a control valve that switches the output target of the working fluid; an actuator driven by the working fluid supplied from the control valve; and an electromagnetic proportional valve that causes a control pressure of the working fluid to act on the control valve, the electromagnetic proportional valve including: a valve portion; and a drive unit that drives the valve portion according to a drive current, the valve portion including a spool having a through hole along an axial direction to which the working fluid flows, the drive unit including: a detection unit that detects information related to the state of at least one of the valve portion 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, the electric drive unit including a housing housing a rod for pressing the spool, the detection unit, and the control unit, the detection unit detecting the control pressure.

[0020] With this configuration, the electromagnetic proportional valve can be controlled based on the control pressure, in addition to the pressure of the working fluid at the pump port.

[0021] Another aspect of the construction machinery of the present invention includes: a fluid system; and a vehicle body on which the fluid system is mounted, the fluid system comprising: a fluid pump that ejects a working fluid; a control valve that switches the output of the working fluid; an actuator driven by the working fluid supplied from the control valve; and an electromagnetic proportional valve that causes a control pressure of the working fluid to act on the control valve, the electromagnetic proportional valve comprising: a valve portion; and a drive unit that drives the valve portion according to a drive current, the valve portion having a spool having an axially extending through-hole through which working fluid from a pump port flows, the drive unit comprising: a detection unit that detects information relating to the state of at least one of the valve portion 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, the electric drive unit having a housing housing a rod for pressing the spool, the detection unit, and the control unit, the detection unit detecting the pressure of the working fluid at the pump port.

[0022] This configuration enables high-precision control of the electromagnetic proportional valve's pressure on the working fluid, providing excellent operability for construction machinery.

[0023] The effects of the invention

[0024] According to the present invention, the structure of electromagnetic proportional valves, fluid systems and electrical control of construction machinery can be simplified and miniaturized. Attached Figure Description

[0025] Figure 1 This is a schematic structural diagram of the construction machinery in an embodiment of the present invention.

[0026] Figure 2 This is a structural diagram of the hydraulic system in an embodiment of the present invention.

[0027] Figure 3 This is a schematic structural diagram of the electromagnetic proportional valve in an embodiment of the present invention.

[0028] Figure 4 This is an illustration of the operation of the electromagnetic proportional valve in an embodiment of the present invention.

[0029] Figure 5 This is a schematic structural diagram of the hydraulic system in a modified embodiment of the present invention.

[0030] Explanation of reference numerals in the attached figures

[0031] 1. Hydraulic system (fluid system); 10. Valve section; 20. Drive unit section; 30. Communication section; 40. Integrated controller (other control sections); 100. Construction machinery; 101. Rotating body (vehicle body); 102. Traveling body (vehicle body); 130. Hydraulic pump (fluid pump); 140. Actuator; 150. Electromagnetic proportional valve; 151. Electrical drive section; 153. Rod; 154. Housing; 170. Detection section; 200. Control section; 500. Control valve; RA, Control port; RD, Discharge port; RP, Pump port; S, Spool valve core; S1, One end; S2, The other end; SH, Through hole. Detailed Implementation

[0032] Next, embodiments of the present invention will be described with reference to the accompanying drawings.

[0033] <Construction Machinery>

[0034] Figure 1 This is a rough structural diagram of construction machinery 100.

[0035] like Figure 1 As shown, the construction machinery 100 is, for example, a hydraulic excavator. The construction machinery 100 includes a slewing body (an example of the vehicle body of the claim) 101, a traveling body (an example of the vehicle body of the claim) 102 disposed on the lower part of the slewing body 101, and a hydraulic system (an example of the fluid system of the claim) 1.

[0036] The slewing body 101 rotates on top of the traveling body 102. The slewing body 101 includes: a cab 103 for an operator to sit in; a boom 104, one end of which is freely connected to the slewing body 101; a stick 105, one end of which is freely connected to the other end (top) of the boom 104; a bucket 106, freely connected to the other end (top) of the stick 105; and an operating unit 108 operated by an operator. The slewing body 101, boom 104, stick 105, and bucket 106 are driven by working fluid (an example of the working fluid in the claims) supplied from the hydraulic system 1.

[0037] <Hydraulic System>

[0038] Figure 2 This is a structural diagram of hydraulic system 1.

[0039] like Figure 2 As shown, the hydraulic system 1 includes: an engine 120 as a drive source; a hydraulic pump (an example of the fluid pump of the claim) 130, which is driven by the engine 120; a plurality of actuators 140 that actuate various parts of the construction machinery 100; a control valve 500 that switches the actuation of the plurality of actuators 140; a solenoid proportional valve 150 that applies control pressure of the working oil to the control valve 500; a tank 160 that stores the working oil; and a pressure adjustment relief valve 300.

[0040] Engine 120 is an internal combustion engine that uses gasoline or diesel fuel. Engine 120 has an output shaft 121. The output shaft 121 is connected to a hydraulic pump 130.

[0041] A hydraulic pump 130 is connected to a pipe Q. The hydraulic pump 130 is driven by the output shaft 121 to spray working oil into the pipe Q. A control valve 500 and a solenoid proportional valve 150 are connected to the pipe Q.

[0042] In this embodiment, the engine 120 is used as the driving source for the working fluid. However, in addition to the engine 120, an electric motor may also be used as the driving source, which uses a power source such as a battery as a power source. Furthermore, the engine 120 may also be used in conjunction with a generator that charges the battery or serves as a power source.

[0043] Multiple actuators 140 are connected to the control valve 500 via a branch pipe Q. The control valve 500 has multiple actuators, and based on the switching operation of the operating unit 108, multiple spool valves switch the hydraulic pressure of the working oil flowing to the pipe Q to supply working oil to the multiple actuators 140. The multiple actuators 140 include hydraulic cylinders that drive the boom 104, stick 105, and bucket 106, and hydraulic motors that rotate the slewing body 101.

[0044] The release valve 300 releases pressure when the pressure of the working oil in the hydraulic circuit (pipeline Q) of the hydraulic system 1 exceeds a preset value.

[0045] The electromagnetic proportional valve 150, based on the operating amount of the operating unit 108, uses hydraulic pressure from the pilot pump (not shown) to move the spool valve core, thereby supplying the actuator 140 with working oil from the hydraulic pump 130. The electromagnetic proportional valve 150 will be discussed in detail below.

[0046] <Solenoid proportional valve>

[0047] Figure 3 This is a schematic diagram of the electromagnetic proportional valve 150.

[0048] like Figure 3 As shown, the electromagnetic proportional valve 150 is used to move the spool of the control valve 500 by controlling the valve opening, thereby adjusting the flow rate of the working oil supplied to the actuator 140 from the hydraulic pump 130. The electromagnetic proportional valve 150 includes: a valve section 10 for applying the control pressure of the working oil to the control valve 500; and a drive unit 20 for driving the valve section 10 according to a drive current.

[0049] The drive unit 20 includes: a detection unit 170 that detects information related to the state of the electromagnetic proportional valve 150; a control unit 200 that generates a control signal (control 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.

[0050] The detection unit 170 detects the pilot pressure of the working oil flowing in the pump port RP, which is connected to the valve unit 10 as described later, as information related to, for example, the state of the valve unit 10. The detection value detected by the detection unit 170 is fed back to the control unit 200.

[0051] The electric drive unit 151 includes, for example, an electromagnetic coil 152 (solenoid) as a drive source; a rod 153 driven by the electromagnetic coil 152; and a housing 154 as an outer casing. The housing 154 is formed to cover the opening of the spool valve core hole H formed in the valve part 10 (described later). Inside the housing 154, the electromagnetic coil 152 (electric drive unit 151), the detection unit 170, and the control unit 200 are arranged and housed in the order of proximity to the valve part 10. In addition, a partition wall 149 is provided inside the housing 154 to divide the housing 154 into a first chamber K1 where the electric drive unit 151 and the detection unit 170 are arranged and a second chamber K2 where the control unit 200 is arranged.

[0052] The electromagnetic coil 152 winds copper wire around an iron core to form a cylindrical shape. The electromagnetic coil 152 generates a magnetic field by passing an electric current through the copper wire.

[0053] Rod 153 is formed of metal in a rod shape. Rod 153 is also referred to as a plunger. The axis of rod 153 is aligned with the axis of electromagnetic coil 152. Rod 153 is configured to move freely in the axial direction within electromagnetic coil 152. One end 153A of rod 153 on the valve part 10 side is abutted by the other end S2 of the spool valve core S, which will be discussed later in the discussion of valve part 10.

[0054] A protrusion 153T is formed on the outer peripheral surface of the rod 153, protruding radially outward. The magnetic field of the electromagnetic coil 152 acts on this protrusion 153T.

[0055] The protrusion 153T of the rod 153 is positioned slightly offset from the neutral axis L of the electromagnetic coil 152 towards the other end 153B of the rod 153 (opposite to one end 153A). Therefore, when the electromagnetic coil 152 is energized, the protrusion 153T (rod 153) is attracted by the magnetic field generated by the electromagnetic coil 152 and moves towards the neutral axis L of the electromagnetic coil 152 (in the direction of the valve section 10). As a result, the rod 153 pushes the spool S of the valve section 10, which will be discussed later.

[0056] The electromagnetic coil 152 proportionally controls the current applied according to the operation amount of the operation unit 108, and the control is based on the detection value detected by the detection unit 170. As a result, the electromagnetic coil 152 adjusts the protrusion amount of the adjustment rod 153. The details of the effect caused by the protrusion amount of the adjustment rod 153 will be discussed later.

[0057] The valve section 10 includes, for example: a cylindrical valve body 155 housed in a valve housing hole 12 formed in the housing 11 of the control valve 500 constituting the hydraulic system 1; a flange 13 disposed on the drive device section 20 side of the valve body 155; a spool valve S housed in a spool valve hole H formed in the valve body 155 in a freely movable manner; and a return spring G that returns the moved spool valve S to its original position.

[0058] A pump port RP is provided in the housing 11, which is connected to the piping Q. Working oil from a pilot pump (gear pump) not shown flows into the pump port RP. In addition, the pilot pump and the hydraulic pump 130 are connected in series with the output shaft 121 of the engine 120, and the pilot pump is also driven by the output shaft 121.

[0059] The housing 11 is provided with: a discharge port RD, which is connected to a flow path communicating with the same tank 160; and a control port RA, which is connected to a flow path communicating with the spool of the control valve 500. Furthermore, "communicating" (to allow...to flow, to allow circulation) refers to the flow of working oil (i.e., fluid). For example, "flow path communicating with tank 160" is a flow path constructed in such a way that working oil flows between that flow path and tank 160.

[0060] The spool valve core hole H of the valve body 155 extends axially through the valve body 155. Starting from one end 155A of the valve body 155 opposite to the drive unit 20, the spool valve core holes H are arranged in the following order: first through hole H1, second through hole H2, third through hole H3, and fourth through hole H4. 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.

[0061] A return spring G is provided in the second through hole H2. The return spring G is an elastic component such as a helical spring. The end GA of the return spring G on the side of the first through hole H1 is in contact with the stepped surface between the first through hole H1 and the second through hole H2. This restricts the movement of the return spring G towards the side of the first through hole H1.

[0062] The first through hole H1 communicates with the pump port RP. An actuator communication hole 156 is formed in the valve body 155, which communicates radially with the third through hole H3 and the control port RA. In addition, a discharge communication hole 157 is formed in the valve body 155, which communicates radially with the fourth through hole H4 and the discharge port RD.

[0063] Multiple sealing members 158 are provided on the outer peripheral surface of the valve body 155, that is, between the valve body 155 and the housing 11, to prevent the first through hole H1, the actuator communication hole 156, and the discharge communication hole 157 from communicating with each other on the outer peripheral surface of the valve body 155. For example, an O-ring can be used as a sealing member 158.

[0064] The flange portion 13 serves to connect the valve body 155 and the drive unit portion 20, and to mount the electromagnetic proportional valve 150 onto the housing 11. A sealing member 159 is provided between the flange portion 13 and the housing 11. For example, an O-ring can be used as the sealing member 159. The sealing between the flange portion 13 and the housing 11 is ensured by the sealing member 159.

[0065] The flange portion 13 is provided in such a way that it blocks the opening of the fourth through hole H4 formed in the valve body 155 on the side near the drive device portion 20. 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 device portion 20 passes.

[0066] A circular plate-shaped support block 14 is provided on the inner surface of the flange portion 13 on the side near the valve body 155. The support block 14 is divided to form a fourth through hole H4. A through hole 14A communicating 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 valve core S on the side near the drive device portion 20, allowing it to move freely in the axial direction. As a result, one end 153A of the rod 153 constituting the drive device portion 20 abuts against the other end S2 of the spool valve core S via the through hole 14A.

[0067] The valve core S is formed of metal in the shape of a rod. One end S1 of the valve core S, opposite to the drive unit 20, is supported in a freely movable manner by the second through hole H2 of the valve body 155.

[0068] The other end GB of the return spring G, which is disposed in the second through hole H2 of the valve body 155, contacts one end S1 of the spool valve S. The return spring G is configured to be compressed by the end S1 and the stepped surface between the first through hole H1 and the second through hole H2 in the valve body 155. The spool valve S is always pushed toward the drive unit 20 by the restoring force of the return spring G.

[0069] A through hole SH is formed along the axial direction in the spool S. The through hole SH communicates with the pump port RP through the first through hole H1 of the valve body 155.

[0070] A protrusion S3 with a diameter larger than that of the two ends S1 and S2 of the valve core S is formed in the axial center of the valve core S. The protrusion S3 is inserted into the third through hole H3 of the valve body 155 in a manner that allows it to move freely in the axial direction.

[0071] The protrusion S3 has a step S4 on the other end S2 side. Step S4 is located within the fourth through hole H4. The pressure of the discharge port RD acts on step S4.

[0072] Additionally, the protrusion S3 has a step S5 on one end S1 side. Step S5 is located within the third through hole H3. The pressure of the control port RA acts on step S5.

[0073] Furthermore, a groove-shaped recess SN (first flow path) extending axially is formed in the protrusion S3. The recess SN has a sealing end SN1 on the step S4 side that does not communicate with the step S4. In addition, the recess SN has an opening end SN2 on the step S5 side that communicates with the step S5.

[0074] Three second flow paths S6 are formed in the protrusion S3, communicating with the through hole SH. The second flow paths S6 are formed in a direction orthogonal to the through hole SH. Three second flow paths S6 are arranged at equal intervals along the circumference at positions avoiding the groove SN.

[0075] <Action of the electromagnetic proportional valve>

[0076] Next, the operation of the electromagnetic proportional valve 150 will be explained.

[0077] First, such as Figure 3 As shown, when the electric drive unit 151 is not driven, the spool valve S is in the neutral position (original position) due to the restoring force of the return spring G. In the neutral position of the spool valve S, the third through hole H3 and the fourth through hole H4 are connected by the spool valve S. That is, the sealing end SN1 of the groove SN is located in the fourth through hole H4, and the opening end SN2 is located in the third through hole H3. Thus, the groove SN connects the third through hole H3 and the fourth through hole H4. As a result, in the neutral position of the spool valve S, the discharge port RD and the control port RA are connected by the groove SN.

[0078] Furthermore, in the neutral position of the valve core S, the third through hole H3 and the first through hole H1 are blocked by the valve core S. That is, the second flow path S6 is housed in the third through hole H3, and the opening of the second flow path S6 is blocked by the inner circumferential surface of the third through hole H3. In addition, one end S1 of the valve core S is inserted into the second through hole H2, therefore, the third through hole H3 and the first through hole H1 are formed by the segment formed by the end S1 of the valve core S. As a result, in the neutral position of the valve core S, the discharge port RD and the control port RA are blocked relative to the pump port RP.

[0079] Working oil flowing in from the pump port RP flows into the through-hole SH through the first through-hole H1, and fills the first chamber K1 of the housing 154 of the electric drive unit 151 from the other end S2 of the spool valve S, generating hydraulic pressure. The detection unit 170 detects the pressure (pilot pressure) of the working oil in the first chamber K1 of the housing 154. Furthermore, a partition wall 149 is provided inside the housing 154 to divide the housing 154 into the first chamber K1, where the electric drive unit 151 and the detection unit 170 are arranged, and the second chamber K2, where the control unit 200 is arranged. Therefore, working oil is prevented from filling the second chamber K2, where the control unit 200 is arranged.

[0080] Next, based on Figure 4 The case where lever 153 is driven by electric drive unit 151 will be explained.

[0081] Figure 4 This is the operation diagram of the electromagnetic proportional valve 150, which is the same as the one mentioned above. Figure 3 Correspondingly.

[0082] like Figure 4 As shown, the electromagnetic coil 152 of the electric drive unit 151 is energized, causing the rod 153 to move towards the valve unit 10. The rod 153 then pushes the spool valve S towards the side opposite to the drive unit 20. The spool valve S moves in the direction that compresses and deforms the return spring G. At this time, the size of the opening of the second flow path S6 communicating with the third through hole H3 increases according to the amount of movement of the spool valve S. As a result, the pump port RP and the third through hole H3 are connected via the first through hole H1, the through hole SH, and the second flow path S6. Consequently, the spool valve S connects the pump port RP and the control port RA, and adjusts the flow rate of the working oil flowing to the control port RA.

[0083] At this time, the working oil flowing in from the pump port RP flows from the pump port RP through the first through hole H1, the second flow path S6, and the third through hole H3 to the control port RA. The detection unit 170 detects the pressure of the working oil in the first chamber K1 inside the housing 154.

[0084] If the movement of the spool valve S ends, the groove SN causes the sealing end SN1 to be 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 valve S blocks the discharge port RD and the control port RA.

[0085] With the spool S in the aforementioned state, 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 working oil supplied from the pump port RP acts on one end S1 of the spool S. Therefore, the detection unit 170 inside the housing 154 can directly detect the pressure (pilot pressure) of the pump port RP based on the amount of movement of the spool S.

[0086] Based on the detection value detected by the detection unit 170, the control unit 200 generates a control signal and performs drive control of the electric drive unit 151 based on the control signal. This allows for appropriate adjustment of the flow rate of the working oil flowing to the control port RA.

[0087] The control valve 500 is driven by the working oil flowing to the control port RA. That is, adjusting the flow rate of the working oil flowing to the control port RA refers to adjusting the control pressure of the working oil to drive the control valve 500. The control unit 200 controls the control pressure of the working oil flowing to the control valve 500.

[0088] The flow rate of working oil supplied to the desired actuator 140 is thus adjusted by the electromagnetic proportional valve 150. Each actuator 140 is driven by the working oil supplied by the control valve 500.

[0089] Thus, the aforementioned electromagnetic proportional valve 150 includes a detection unit 170 and a control unit 200. By providing the detection unit 170 and the control unit 200 within the electromagnetic proportional valve 150 itself, unnecessary space can be avoided outside the electromagnetic proportional valve 150, allowing for miniaturization of the electromagnetic proportional valve 150. Furthermore, the overall structure of the hydraulic system 1 can be simplified.

[0090] The control unit 200 performs drive control on the electric drive unit 151 for driving the spool valve S (valve unit 10). The pump port RP of the electromagnetic proportional valve 150 is connected to the through hole SH formed in the spool valve S. The detection unit 170 detects the force applied to the rod 153 that abuts against the spool valve S, thereby making it easy to detect the pressure (pilot pressure) of the working oil flowing in the pump port RP based on the amount of movement of the spool valve S. That is, according to the electromagnetic proportional valve 150, the detection unit 170 detects the pressure applied to the spool valve S connected to the pump port RP in the movement direction, thus simplifying the structure of the device for detecting the pilot pressure.

[0091] Within the housing 154 of the electric drive unit 151, the electromagnetic coil 152 (electric drive unit 151), the detection unit 170, and the control unit 200 are arranged in the following order from the valve unit 10 side. Therefore, the drive unit 20 can be miniaturized as much as possible, and the various components constituting the drive unit 20 can be easily integrated.

[0092] Additionally, the working oil flows into the housing 154 through the through hole SH of the slide valve core S. The detection unit 170 is arranged adjacent to the electromagnetic coil 152 (electric drive unit 151), thus extending the path of the working oil to the detection unit 170 without waste, reducing hysteresis, and improving the responsiveness of the detection unit 170. Furthermore, the pressure of the working oil flowing in the pump port RP can be easily detected using the detection unit 170 with a simple structure.

[0093] In addition, the construction machinery 100 equipped with such a hydraulic system 1 can control the control pressure of the working oil by the electromagnetic proportional valve 150 with high precision, thereby improving operability.

[0094] [Variation Example]

[0095] Furthermore, the present invention is not limited to the embodiments described above, and includes various modifications to the embodiments described above without departing from the spirit of the present invention.

[0096] For example, in the above embodiments, the case where working oil is used as the working fluid has been described, and the case where hydraulic system 1 is used as a fluid system has been described. However, it is not limited to this; the working fluid may also be a fluid other than working oil. The structure of the electromagnetic proportional valve 150 described above can be adopted in a variety of fluid systems corresponding to the type of working fluid. Even in the case of hydraulic system 1, hydraulic system 1 is not only suitable for construction machinery, but also for other devices that use working fluids, such as hydraulic presses.

[0097] In the above embodiment, the case where the detection unit 170 detects the pilot pressure of the working oil flowing in the pump port RP as information related to the state of the valve section 10 has been described. However, it is not limited to this; the detection unit 170 may be able to detect information related to the state of at least one of the valve section 10 and the drive unit 20 required for controlling the electromagnetic proportional valve 150. For example, the detection unit 170 may also detect the position of the spool S, the acceleration of the spool S, the strain of the spool S, the temperature of the spool S, the control pressure of the working oil used to drive the control valve 500, etc., as information related to the state of the valve section 10.

[0098] Alternatively, the detection unit 170 may detect the pressure of the working oil flowing through the through-hole SH formed in the spool valve S instead of detecting the pilot pressure of the working oil flowing in the pump port RP as information related to the state of the valve section 10. This is because the working oil flowing in from the pump port RP flows into the through-hole SH through the first through-hole H1, and fills the first chamber K1 within the housing 154 of the electric drive section 151 from the other end S2 of the spool valve S, generating hydraulic pressure. Therefore, detecting the pressure of the working oil flowing in the through-hole SH refers to detecting the pilot pressure of the working oil flowing in the pump port RP.

[0099] Additionally, the temperature of the working oil can also be information related to the state of the valve section 10 and the drive unit section 20. For example, the temperature of the working oil inside the spool S is information related to the state of the valve section 10, while the temperature of the working oil inside the housing 154 is information related to the state of the drive unit section 20. The temperature of any part of the drive unit section 20 is also information related to the state of the drive unit section 20.

[0100] Specific examples of the temperature of any part of the drive unit 20 include, for example, the temperature of the working oil in the electric drive unit 151, and the temperatures of the electromagnetic coil 152, rod 153, and housing 154 constituting the electric drive unit 151. Additionally, the detection unit 170 can detect information related to the state of the drive unit 20, such as the position of the rod 153 and the speed at which the rod 153 moves.

[0101] In the above embodiment, the case where the control unit 200 performs drive control of the electric drive unit 151 has been described. However, it is not limited to this; the control unit 200 may also include a communication unit 30 (see reference 1). Figure 5 The following is an example of the communications section 30.

[0102] Figure 5 This is a schematic structural diagram showing a modified example of hydraulic system 1.

[0103] like Figure 5 As shown, the hydraulic system 1 can also be driven and controlled by a plurality of electromagnetic proportional valves 150, for example, by a comprehensive 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 comprehensive controller 40. Thus, the comprehensive controller 40 can be used to comprehensively control each electromagnetic proportional valve 150. Furthermore, by pre-installing the communication unit 30 in the control unit 200, the comprehensive controller 40 can communicate with the electromagnetic proportional valves 150 without making significant modifications to the comprehensive controller 40. Therefore, a hydraulic system 1 with excellent convenience can be provided.

[0104] Furthermore, in the above embodiment, the electromagnetic proportional valve 150 was described as being used to apply the control pressure of the working oil to the control valve 500. However, it is not limited to this, and the structure of the electromagnetic proportional valve 150 can be adopted from various electromagnetic proportional valve structures used to control the control pressure of the working oil flowing to fluid equipment (hydraulic equipment).

[0105] In the above embodiment, the valve core hole H of the valve body 155 is described as follows: starting from one end 155A of the valve body 155 opposite to the drive unit 20, the first through hole H1, the second through hole H2, the third through hole H3, and the fourth through hole H4 are arranged in that order. Furthermore, the case where the first through hole H1 communicates with the pump port RP is described. The case where the valve body 155 has an actuator communication hole 156 that radially communicates with the third through hole H3 and the control port RA is described. However, this is not a limitation; the pump port RP and the control port RA can also be configured in reverse order. That is, it is also possible for the first through hole H1 to communicate with the control port RA and the third through hole H3 to communicate radially with the pump port RP. In this case, the detection unit 170 detects, for example, the pressure of the working oil flowing in the control port RA. Even with this configuration, it achieves the same effect as the embodiment described above. In addition, besides the pilot pressure of the working oil flowing in the pump port RP, the electromagnetic proportional valve can also be controlled based on the control pressure of the control valve 500.

[0106] Industrial availability

[0107] According to the present invention, the structure of electromagnetic proportional valves, fluid systems and electrical control for construction machinery can be simplified and miniaturized.

Claims

1. An electromagnetic proportional valve comprising: a valve portion; and a drive device portion that drives the valve portion in accordance with a drive current, the valve portion comprising: a valve main body that communicates with a pump port through which a working fluid flows, and that has a spool bore formed in an axial direction; and a spool that is housed in the spool bore in a freely movable manner, the spool having a through-hole formed in an axial direction thereof, the through-hole communicating with the pump port, and the working fluid from the pump port flowing into the through-hole, the drive device portion being coupled to the valve main body on a side opposite the pump port in the axial direction of the valve main body, the drive device portion comprising: a detection portion that detects information related to a state of at least either one of the valve portion and the drive device portion; and an electric drive portion that drives the spool, the electric drive portion comprising: a rod that urges the spool toward a side opposite the drive device portion; and a housing that houses the rod, the detection portion, and the control portion, and that is formed so as to cover an opening of the spool bore, the detection portion detecting a pressure of the working fluid at the pump port as the information, the control portion performing drive control of the electric drive portion, the detection portion and the control portion being arranged in the housing in the axial direction of the spool.

2. The electromagnetic proportional valve according to claim 1, wherein the detection portion detects a pressure of the working fluid flowing in the through-hole as the information, thereby detecting the pressure of the working fluid at the pump port.

3. The electromagnetic proportional valve according to claim 1, wherein the spool, the electric drive portion, the detection portion, and the control portion are arranged in the axial direction of the spool in the order of the spool, the electric drive portion, the detection portion, and the control portion.

4. The electromagnetic proportional valve according to any one of claims 1 to 3, wherein the control portion comprises a communication portion that transmits and receives information with respect to other control portions.

5. A fluid system comprising: a fluid pump that ejects a working fluid; a control valve that switches an output target of the working fluid; an actuator that is driven by the working fluid supplied from the control valve; and an electromagnetic proportional valve that causes a control pressure of the working fluid to act on the control valve, the electromagnetic proportional valve comprising: a valve portion; and a drive device portion that drives the valve portion in accordance with a drive current, the valve portion comprising: a valve main body that communicates with a pump port, the pump port communicating with the fluid pump, and the valve main body having a spool bore formed in an axial direction; and a spool that is housed in the spool bore in a freely movable manner, the spool having a through-hole formed in an axial direction thereof, the through-hole communicating with the pump port, and the working fluid from the pump port flowing into the through-hole, the drive device portion being coupled to the valve main body on a side opposite the pump port in the axial direction of the valve main body, the drive device portion comprising: a detection portion that detects information related to a state of at least either one of the valve portion and the drive device portion; and an electric drive portion that drives the spool, the electric drive portion comprising: a rod that urges the spool toward a side opposite the drive device portion; and a housing that houses the rod, the detection portion, and the control portion, and that is formed so as to cover an opening of the spool bore, the detection portion detecting a pressure of the working fluid at the pump port as the information, the control portion performing drive control of the electric drive portion, the detection portion and the control portion being arranged in the housing in the axial direction of the spool. ​ ​ ​ ​ ​ a control section that controls the drive current based on a detection result of the detection section; ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ a detection unit that detects information about a state of at least either one of the valve unit and the drive device unit; a control section that controls the drive current based on a detection result of the detection section; and an electric drive unit that drives the spool using the drive current, the electric drive unit includes: a rod that pushes the spool toward a side opposite to the drive device unit; and a housing that houses the rod, the detection unit, and the control unit, and is formed in a manner to cover an opening of the spool hole, the detection unit detects a pressure of the working fluid at the pump port as the information, the control unit performs drive control of the electric drive unit, the detection unit and the control unit are arranged in the housing in a manner to be aligned along an axial direction of the spool.

6. A construction machine including: a fluid system; and a vehicle body that mounts the fluid system, the fluid system includes: a fluid pump that discharges a working fluid; a control valve that switches an output target of the working fluid; an actuator that is driven by the working fluid supplied from the control valve; and a solenoid proportional valve that causes a control pressure of the working fluid to act on the control valve, the solenoid proportional valve includes: a valve unit; and a drive device unit that drives the valve unit according to a drive current, the valve unit includes: a valve body that communicates with a pump port, the pump port communicating with the fluid pump, and the valve body being formed with a spool hole in an axial direction; and a spool that is housed in the spool hole in a freely movable manner, the spool is formed with a through hole in the axial direction, the through hole communicating with the pump port, and the working fluid from the pump port flowing to the through hole, the drive device unit is connected to the valve body in a manner to be located on a side opposite to the pump port in the axial direction of the valve body, the drive device unit includes: a detection unit that detects information about a state of at least either one of the valve unit and the drive device unit; a control section that controls the drive current based on a detection result of the detection section; and an electric drive unit that drives the spool using the drive current, the electric drive unit includes: a rod that pushes the spool toward a side opposite to the drive device unit; and a housing that houses the rod, the detection unit, and the control unit, and is formed in a manner to cover an opening of the spool hole, the detection unit detects a pressure of the working fluid at the pump port as the information, the control unit performs drive control of the electric drive unit, the detection unit and the control unit are arranged in the housing in a manner to be aligned along an axial direction of the spool.

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