JP2011163433A - Solenoid proportional throttle valve - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a solenoid proportional throttle valve in which a maximum flow rate is not influenced by the dimensional tolerance of a magnetic path member such as a plunger or a base. <P>SOLUTION: The solenoid proportional throttle valve 1 adapted to drive the plunger 4 by the magnetic field generated to a coil 12 and to axially move a shaft 5 connected to the plunger 4 to adjust a valve opening, includes a valve seat 37 through which a hydraulic fluid flows; a poppet 17 throttling the flow of the hydraulic fluid between itself and the valve seat 37; and a stroke regulating means for regulating the stroke of the poppet 17 to the valve seat 37 by partial abutting of the poppet 17 when the poppet 17 is displaced in a valve opening direction (in a right direction in the figure) together with a shaft 5. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention relates to an electromagnetic proportional throttle valve that controls a flow rate of a working fluid by adjusting an opening area of a variable throttle portion according to an exciting current.

  In general, an electromagnetic proportional throttle valve (electromagnetic proportional flow control valve) is widely used to electrically control the operation of a power steering device provided in a vehicle.

  Conventionally, this type of electromagnetic proportional throttle valve has a valve hole communicating with the pressure source side and the load side, a shaft supported so as to be axially displaceable with respect to the valve hole, and an urging force of the shaft in the axial direction. And a coil that drives the shaft against the spring by solenoid thrust, and the opening area of the variable restrictor defined in the valve hole is changed with the displacement of the shaft.

  As for what was disclosed by patent document 1, the poppet which defines a variable throttle part between valve holes is formed separately from the shaft.

  According to this, according to the required maximum control flow rate, the outer diameter of the poppet and the opening diameter of the valve hole are set large, and the opening area of the variable throttle portion is expanded. By forming the poppet separately from the shaft, even if the poppet's outer diameter is increased, there is no need to increase the radial dimension of each part, including the shaft and its bearings. can avoid.

JP 2002-147642 A

  When such a conventional electromagnetic proportional throttle valve has the maximum valve opening, the shaft moves so that the plunger comes into contact with a member such as a base, and the opening area of the variable throttle portion does not increase further. .

  However, with conventional electromagnetic proportional throttle valves, the maximum valve opening is determined by the dimensions of many parts such as poppets, shafts, plungers, bases, etc., so the maximum flow rate accuracy that can be obtained with the maximum valve opening Therefore, it is necessary to strictly manage the dimensional tolerance of each of these parts, and there is a problem that the cost of the product is increased.

  The present invention has been made in view of the above problems, and an object thereof is to provide an electromagnetic proportional throttle valve whose maximum flow rate is not affected by dimensional tolerances of magnetic path members such as a plunger and a base.

  The present invention is an electromagnetic proportional throttle valve in which a plunger is driven by a magnetic field generated in a coil, and a valve opening is adjusted by moving a shaft coupled to the plunger in the axial direction, and a valve through which hydraulic oil flows A poppet that restricts the flow of hydraulic oil between the seat and the valve seat, and when the poppet is displaced in the valve opening direction together with the shaft, a part of the poppet is brought into contact to regulate the stroke of the poppet to the valve seat. It is characterized by having a configuration including a stroke restricting means.

  According to the present invention, since the parts that determine the maximum valve opening are mainly the poppet and the valve seat, there is no influence on the dimensional accuracy of the parts such as the shaft as in the conventional apparatus, and the variation in the maximum flow rate that occurs for each product. Can be kept small and quality can be improved. And since other parts, such as a base and a shaft, do not affect the maximum valve opening, it is possible to set a large dimensional tolerance in the central axis direction of the shaft, thereby reducing the cost of the product.

Sectional drawing of the electromagnetic proportional throttle valve which shows embodiment of this invention.

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

  An electromagnetic proportional throttle valve (electromagnetic proportional flow control valve) 1 shown in FIG. 1 is attached to a base unit of a hydraulic device (not shown) and throttles the flow of hydraulic fluid (working fluid) discharged from a pump provided in the base unit. The flow rate of the hydraulic fluid led to is adjusted.

  Note that a working fluid such as a water-soluble alternative liquid may be used instead of the oil as the working oil.

  The electromagnetic proportional throttle valve 1 includes a case 9, a base 2, a plunger 4, a shaft 5, first and second bearings 7 and 8, a coil assembly 10, and the like as components.

  The coil assembly 10 includes an electromagnetic coil 12 disposed around the plunger 4, and constitutes an electromagnetic actuator that drives the plunger (movable iron core) 4 by a magnetic field generated in the coil 12.

  The coil assembly 10 includes a cylindrical bobbin 11 having flanges at both ends, a coil 12 formed by winding a magnet wire around the bobbin 11, and a pair of terminals coupled to both ends of the magnet wire of the coil 12. 13 and a mold resin 14 surrounding the coil 12.

  The mold resin 14 has a cylindrical surrounding portion 16 in which the bobbin 11 and the coil 12 are accommodated, and a connector portion 15 that protrudes from one end of the surrounding portion 16 and faces the terminal 13. A mating connector (not shown) is inserted into the connector portion 15. When the coil 12 is energized through the mating connector, a magnetic field is generated around the coil 12. Not limited to this, the coil 12 may be energized via a lead wire.

  As a magnetic path constituent member for guiding the magnetic flux of the coil 12, a case 9, a base 2, and a plunger 4 are provided, which are each formed of a magnetic material.

  The case 9 is formed in a bottomed cylindrical shape, and has a plurality of flange portions 91 protruding from the opening end portions thereof, and bolt holes 98 are opened in the flange portions 91. The case 9 is fastened to the mounting seat of the mother machine by a bolt (not shown) that passes through each bolt hole 98.

  A coil assembly 10 is accommodated inside the case 9. A notch 97 opening on the side surface of the case 9 is formed. The connector portion 15 protrudes from the cutout portion 97 to the outside of the case 9.

  In the figure, O is the center line of the shaft 5. The terminal 13 accommodated in the connector portion 15 extends in the same direction as the center line O, and the mating connector is inserted and removed in the same direction as the center line O. Not only this but the direction where the terminal 13 extends is arbitrarily arrange | positioned corresponding to the shape of the main | base machine in which the electromagnetic proportional throttle valve 1 is attached.

  A cylindrical sleeve 3 is integrally formed on the back side of the case 9. The sleeve 3 may be formed separately from the case 9 without being limited thereto.

  The base 2 is disposed on the opening end side of the case 9, and the sleeve 3 is disposed on the back side of the case 9. The cylindrical base 2 and the sleeve 3 are arranged inside the case 9 so as to be coaxial with the center line O, and the shaft 5 and the plunger 4 are arranged inside each of them.

  The sleeve 3 is assembled by fitting its outer peripheral surface 31 to the inner peripheral surface of the bobbin 11. The outer peripheral surface 25 of the base 2 is fitted to the inner peripheral surface of the bobbin 11.

  The shaft 5 is made of a nonmagnetic material and is formed in a hollow cylindrical shape. The shaft 5 passes through the sleeve 3 and the base 2 and is supported so as to be slidable in the direction of the center line O via the first and second bearings 7 and 8.

  The plunger 4 is made of a magnetic material and is formed in a hollow cylindrical shape. The inner peripheral surface of the plunger 4 is fitted to the outer peripheral surface of the shaft 5 and is coupled to the shaft 5 by welding or caulking. The plunger 4 is disposed between the first and second bearings 7 and 8.

  The sleeve 3 has a small-diameter sleeve inner peripheral surface 34 and a large-diameter sleeve inner peripheral surface 33 on the inner periphery thereof.

  The outer peripheral surface 81 of the second bearing 8 is fitted and attached to the inner peripheral surface 34 of the small diameter sleeve.

  An annular gap 55 is formed between the large-diameter sleeve inner peripheral surface 33 and the plunger outer peripheral surface 41.

  The base 2 has base inner peripheral surfaces 26 to 29 having different diameters on the inner periphery thereof.

  The outer peripheral surface 71 of the first bearing 7 is fitted and attached to the base inner peripheral surface 26 having the second smallest diameter.

  The base inner peripheral surfaces 27 and 28 define a gap 56 with the outer peripheral surface 51 of the shaft 5.

  The base inner peripheral surface 29 having the largest diameter defines an annular gap 55 between the plunger outer peripheral surface 41.

  A coiled spring 24 is compressed and interposed between the base 2 and the plunger 4. One end of the spring 24 abuts on an annular step formed between the base inner peripheral surface 27 and the base inner peripheral surface 28. The other end of the spring 24 contacts the front end surface 47 of the plunger 4. The spring 24 urges the plunger 4 in the right direction (the valve opening direction) in the drawing and pulls the shaft 5.

  The base 2 is formed with a base adsorption surface 46 that adsorbs the plunger 4 by magnetic force. The base suction surface 46 is formed as an annular step between the base inner peripheral surface 28 and the base inner peripheral surface 29. The base suction surface 46 is formed in a planar shape orthogonal to the center line O and faces the plunger front end surface 47 in parallel.

  The base 2 has an annular tapered end surface 45 that is inclined with respect to the center line O. The position and shape (inclination angle with respect to the center line O) of the annular tapered end face 45 are arbitrarily set, and the magnetic flux density from the base 2 toward the plunger 4 is adjusted.

  On the other hand, the sleeve 3 has an annular end surface 35 orthogonal to the center line O. The annular end face 35 may be inclined without being orthogonal to the center line O.

  The first and second bearings 7 and 8 are made of a nonmagnetic material.

  The magnetic flux generated inside the coil 12 is guided by the case 9, the base 2, the plunger 4, and the sleeve 3. Since the magnetic flux passing between the base 2 and the sleeve 3 is blocked by the magnetic gap, it is guided through the plunger 4 and travels from the base 2 to the plunger 4.

  The magnetic flux density from the base 2 toward the plunger 4 varies depending on the shape and position of the magnetic gap. The shape and position of the magnetic gap are arbitrarily set so that a solenoid thrust corresponding to the stroke of the plunger 4 moving in the direction of the center line O can be obtained.

  In the electromagnetic proportional throttle valve 1, a plunger front chamber 74, a plunger back chamber 75, and a second bearing back chamber 76 are provided around the shaft 5 and the plunger 4, and hydraulic oil from the mother machine is guided to these.

  The plunger front chamber 74 is defined between the first bearing 7 and the plunger front end surface 47.

  The 1st bearing 7 does not have a flow path which penetrates this, and fulfill | performs the function which interrupts | blocks the shortest path | route which the plunger front chamber 74 connects with respect to a main | base machine.

  The plunger back chamber 75 is defined between the end surface 48 of the plunger 4 and the second bearing 8.

  The plunger 4 is interposed between the plunger front chamber 74 and the plunger back chamber 75. An annular gap 55 is defined around the plunger outer peripheral surface 41 to prevent magnetic adsorption between the sleeve 3 and the plunger 4. The gap 55 constitutes a plunger outer circumferential path 63 that allows the plunger front chamber 74 and the plunger back chamber 75 to communicate with each other.

  A plurality of grooves 42 are formed in the plunger outer peripheral surface 41 as the plunger outer peripheral path 63. The hydraulic oil is configured to flow between the plunger front chamber 74 and the plunger back chamber 75 through the grooves 42.

  By defining the plunger outer circumferential path 63 by the plurality of grooves 42, the clearance of the gap 55 can be reduced. By reducing the clearance of the gap 55, the magnetic efficiency for driving the plunger 4 can be increased.

  The second bearing back chamber 76 is provided behind the second bearing 8, and is defined between the second bearing 8 and the bottom surface 93 of the case 9.

  The second bearing 8 is interposed between the plunger back chamber 75 and the second bearing back chamber 76. A plurality of grooves 82 are formed on the outer peripheral surface 81 of the second bearing 8. These grooves 82 constitute a second bearing through passage 64 that allows the plunger back chamber 75 and the second bearing back chamber 76 to communicate with each other.

  A vertical through hole 53 that penetrates the shaft 5 in the direction of the center line O and a horizontal through hole 54 that penetrates the shaft 5 in the radial direction orthogonal to the center line O are formed. The vertical through hole 53 and the horizontal through hole 54 constitute a shaft through path 65 that communicates the valve chamber 61 and the second bearing rear chamber 76.

  A filler ring 6 that fits over the outer periphery of the sleeve 3 and the case 9 is provided. The filler ring 6 is formed in a thin cylindrical shape made of a nonmagnetic material. The filler ring 6 covers a magnetic gap between the base 2 and the sleeve 3, and constitutes a pressure vessel that accommodates the plunger 4 and the shaft 5 by the sleeve 3 and the case 9. In the electromagnetic proportional throttle valve 1, hydraulic oil flows from the mother machine through the shaft through passage 65, but the hydraulic oil is supplied to the electromagnetic proportional throttle valve 1 by a pressure vessel constituted by the sleeve 3, the filler ring 6, and the case 9. Leakage to the outside is prevented.

  The electromagnetic proportional throttle valve 1 includes a valve seat 37 in which a valve hole 38 is opened and a poppet 17 attached to the tip of the shaft 5 as a part for restricting the flow of hydraulic oil discharged from a pump provided in the mother machine.

  The poppet 17 is formed in a bottomed cylindrical shape as a separate body from the shaft 5 and is fitted and attached to the tip of the shaft 5. One end of the shaft through passage 65 is closed by the poppet 17. The other end of the shaft through passage 65 communicates with the second bearing back chamber 76.

  The poppet 17 has a base end face 19 facing the base 2 side, and the base end face 19 is formed in a planar shape orthogonal to the center line O.

  An annular recess 59 is formed on the inner periphery of the poppet 17, and a plurality of notches 60 that open across the recess 59 and the poppet base end surface 19 are formed. The notch 60 constitutes a poppet internal / external communication passage 66 in which the valve chamber 61 and the shaft through passage 65 communicate with each other. As shown in the figure, even when the poppet base end surface 19 is in the fully open state in contact with the base end surface 58, the valve chamber 61 in the valve seat 37 communicates with the lateral through hole 54 via the notch 60 and the recess 59. The hydraulic oil flows between the valve chamber 61 and the shaft through passage 65.

  As for the poppet 17, the poppet front end surface 18 which protrudes toward the inside of the valve hole 38 is formed in the cone surface shape centering on the centerline O at the front-end | tip.

  The valve seat 37 is formed in a cylindrical shape, and is fitted and attached to the base 2.

  The base 2 has an inlay portion 57 into which the outer peripheral surface 36 of the valve seat 37 is fitted, and a base end surface 58 with which the base end surface 43 of the valve seat 37 abuts. The inlay portion 57 is formed in a cylindrical surface shape with the center line O as the center. The base end surface 58 is formed in a planar shape orthogonal to the center line O.

  In the valve seat 37, the valve hole 38 and the poppet accommodation hole 39 are formed with the center line O as the center, and the plurality of through holes 40 are formed in a direction orthogonal to the center line O.

  A valve seat wall 79 is formed inside the valve seat 37 as an annular step. The valve seat wall 79 is formed between the valve hole 38 and the poppet accommodation hole 39 in a planar shape perpendicular to the center line O.

  The valve chamber 61 is defined by the valve seat wall 79 and the poppet accommodation hole 39 and accommodates the poppet 17.

  A disc-shaped base collar portion 21 and a base fitting portion 22 are formed at one end of the base 2. In the base 2, the base flange portion 21 is coupled to the opening end portion of the case 9 and is disposed coaxially with the center line O.

  The end surface 96 of the case 9 abuts on a mounting seat of a mother machine (not shown).

  When the electromagnetic proportional throttle valve 1 is assembled to the mother machine, the cylindrical base fitting part 22 is fitted to the spigot part of the mother machine (not shown). A seal ring 23 is interposed on the outer periphery of the base fitting portion 22. The seal ring 23 seals the mounting portion of the electromagnetic proportional throttle valve 1 with respect to the mother machine, thereby preventing the working oil of the mother machine from leaking outside.

  After the electromagnetic proportional throttle valve 1 is assembled to the mother machine, hydraulic oil from the mother machine is filled into the electromagnetic proportional throttle valve 1 through the following path.

  The hydraulic oil from the mother machine is filled into the second bearing rear chamber 76 through the valve chamber 61 and the shaft through passage 65 (the horizontal through hole 54 and the vertical through hole 53).

  The hydraulic oil in the second bearing back chamber 76 is filled into the plunger back chamber 75 through the second bearing through passage 64 (groove 82).

  The hydraulic oil in the plunger back chamber 75 is filled into the plunger front chamber 74 through the plunger outer peripheral path 63 (gap 55, groove 42).

  The electromagnetic proportional throttle valve 1 drives the plunger 4 by the magnetic force of the coil 12, slides the shaft 5 coupled to the plunger 4 in the axial direction, and moves the poppet 17.

  When the coil 12 is not energized, the shaft 5 is held at the fully open position of the poppet 17 by the biasing force of the spring 24.

  When the coil 12 is energized, the plunger 4 is driven toward the base 2 by a solenoid thrust force that attracts the plunger 4 to the base adsorption surface 46 of the base 2 by the magnetic field generated inside the coil 12, and the shaft 5 is moved forward (see FIG. And move the poppet 17 in the closing direction.

  When the shaft 5 slides forward, the volume of hydraulic oil from which the shaft 5 retreats from the second bearing back chamber 76 flows from the valve chamber 61 through the shaft through passage 65 into the second bearing back chamber 76.

  At this time, when the plunger 4 moves forward, hydraulic oil corresponding to the moving volume of the plunger 4 flows from the plunger front chamber 74 that contracts into the plunger back chamber 75 that extends through the plunger outer circumferential path 63.

  When the energization of the coil 12 is stopped, the shaft 5 slides backward (rightward in the drawing) by the urging force of the spring 24, and the poppet 17 moves to the fully open position.

  When the shaft 5 slides rearward, the volume of hydraulic oil into which the shaft 5 enters the second bearing back chamber 76 flows out from the second bearing back chamber 76 through the shaft through passage 65 and the valve chamber 61 to the mother machine. .

  At this time, when the plunger 4 moves rearward, the hydraulic oil corresponding to the moving volume of the plunger 4 flows from the plunger back chamber 75 that contracts into the plunger front chamber 74 that extends through the plunger outer peripheral path 63.

  By the way, the hydraulic fluid guided from the mother machine to the electromagnetic proportional throttle valve 1 includes contaminations such as wear powder generated in the mother machine. Among these contaminants, magnetic iron powder or the like enters the plunger front chamber 74 and the plunger back chamber 75 of the electromagnetic proportional throttle valve 1, and a strong magnetic field in which magnetic flux concentrates between the base 2 and the end of the plunger 4. Gather in part B. When many contaminants adhere to the surface of the magnetic material (base 2 and plunger 4) constituting the strong magnetic field part B, the following problems occur.

  The solenoid thrust that attracts the plunger 4 to the base attracting surface 46 of the base 2 is changed by the magnetic field generated around the coil 12.

  The sliding resistance of the plunger 4 increases, the hysteresis characteristic of the electromagnetic proportional throttle valve 1 increases, and the stroke range in which the plunger 4 slides is narrowed.

  In response to this, the electromagnetic proportional throttle valve 1 cuts off the communication between the valve chamber 61 and the plunger front chamber 74 by the first bearing 7, and the hydraulic fluid of the mother machine is connected to the shaft through passage 65 and the second bearing rear chamber 76. The plunger is guided to the plunger back chamber 75 through the second bearing through passage 64. As a result, the path for the contamination of the hydraulic oil to reach the strong magnetic field portion B around the plunger 4 is lengthened, and the contamination adheres to the surface of the magnetic material (base 2, plunger 4) constituting the strong magnetic field portion B, and accumulates. Can be suppressed. Thereby, the malfunction of the electromagnetic proportional throttle valve 1 resulting from the contamination of hydraulic oil can be prevented, and the movable time during which the electromagnetic proportional throttle valve 1 operates stably can be extended.

  Further, since the second bearing back chamber 76 expanded and contracted by sliding of the shaft 5 communicates with the plunger back chamber 75 via the second bearing through passage 64, pressure fluctuation from the mother machine is caused by the second bearing back chamber. Even when the pressure is transmitted to 76, the pressure fluctuation in the second bearing back chamber 76 is transmitted to the plunger back chamber 75 through the second bearing through passage 64, and the second bearing 8 is pressured in the second bearing back chamber 76 and the plunger back chamber 75. It is possible to prevent movement (dropout) due to the difference.

  The plunger outer circumferential path 63 includes an annular gap 55 defined around the plunger outer circumferential surface 41 to prevent magnetic adsorption between the sleeve 3 and the plunger 4, and a plurality of grooves 42 opened in the plunger outer circumferential surface 41. Therefore, when the plunger 4 moves, the flow speed of the hydraulic oil around the plunger 4 is suppressed, the viscosity resistance of the hydraulic oil applied to the plunger 4 is reduced, and the operation response of the electromagnetic proportional throttle valve 1 is improved. It is done. Thus, when the plunger 4 moves at a high speed, the contamination accumulated on the plunger 4 is removed. Thereby, the malfunctioning of the electromagnetic proportional throttle valve 1 resulting from the contamination of hydraulic oil can be prevented.

  Since the plunger outer circumferential path 63 includes a plurality of grooves 42 formed on the plunger outer circumferential surface 41, the flow path cross-sectional area of the plunger outer circumferential path 63 is expanded by these grooves 42. Thereby, when the plunger 4 moves, the flow of the hydraulic oil around the plunger 4 is suppressed, the viscosity resistance of the hydraulic oil applied to the plunger 4 is reduced, and the operation responsiveness of the electromagnetic proportional throttle valve 1 can be improved.

  The hydraulic oil discharged from the pump provided in the mother machine passes through the through hole 40, the valve chamber 61, the variable throttle 30 and the valve hole 38 of the electromagnetic proportional throttle valve 1 to the load side as indicated by arrows in the figure. Led. In addition, it is good also as a structure which flows not only in this but in the reverse direction to the direction shown by the arrow in a figure.

  The electromagnetic proportional throttle valve 1 has an annular shape between the poppet tip surface 18 and an annular opening edge (edge portion) 77 with respect to the valve seat wall 79 of the valve hole 38 as a variable throttle 30 for restricting the flow of hydraulic oil. Define the gap. The electromagnetic proportional throttle valve 1 adjusts the flow rate of the hydraulic fluid guided to the load side by giving resistance to the flow of hydraulic fluid discharged from the pump by the variable throttle portion 30.

  When the poppet 17 moves leftward in the drawing and the poppet tip surface 18 contacts the opening edge 77 of the valve hole 38, the opening area of the variable throttle portion 30 becomes zero, and the variable throttle portion 30 is fully closed (closed). Is done.

  When the poppet 17 moves rightward in the figure, the poppet tip surface 18 moves away from the opening edge portion 77 of the valve hole 38, and the opening area of the variable throttle portion 30 gradually increases according to the stroke of the poppet 17 with respect to the valve seat 37.

In the state where the hydraulic oil flows as shown by the arrows in the figure, the following four can be cited as forces acting on the poppet 17.
Fsol: solenoid thrust force of the coil 12 acting on the plunger 4 Fk: spring force FΔP of the spring 24: force due to the differential pressure ΔP across the variable throttle 30 Ff: fluid force generated in the variable throttle 30

The following formula is established for the relationship between the forces acting on the poppet 17.
Fsol = Fk−FΔP−Ff (1)

  The poppet 17 moves to a position where the above equation is established, and a control flow rate Qc proportional to the opening area Av of the variable throttle unit 30 and the differential pressure ΔP across the variable throttle unit 30 obtained thereby flows.

  The opening area Av of the variable throttle portion 30 is set by setting the outer diameter of the poppet 17 and the opening diameter of the valve hole 38 large in accordance with the required maximum control flow rate Qcmax.

  By forming the poppet 17 separately from the shaft 5, it is not necessary to increase the outer diameter of the shaft 5 even if the outer diameter of the poppet 17 is increased. Therefore, it is possible to avoid the enlargement of the size of the electromagnetic proportional throttle valve 1.

  When the poppet 17 is displaced in the valve opening direction (rightward in the figure), the electromagnetic proportional throttle valve 1 restricts the stroke (displacement amount) of the poppet 17 with respect to the valve seat 37 by contacting a part of the poppet 17. Stroke regulating means is provided.

  This stroke restricting means has a configuration in which the poppet base end surface 19 is brought into contact with the base end surface 58 of the base 2 to stop the poppet 17 from being displaced further.

  In the electromagnetic proportional throttle valve 1, the poppet base end surface 19 abuts on the base end surface 58 of the base 2, and the stroke of the poppet 17 with respect to the valve seat 37 is restricted, so that the opening area of the variable throttle portion 30 is maximized. It becomes.

  The electromagnetic proportional throttle valve 1 has a configuration in which the base end face 19 of the poppet 17 is arranged on the base end face 43 of the valve seat 37 and the base end face 58 of the base 2 in the fully opened state, so that the maximum opening area of the variable throttle portion 30 is the poppet. 17 and the dimensional accuracy of two parts of the valve seat 37.

  In contrast, when the conventional electromagnetic proportional throttle valve has the maximum valve opening, the shaft moves and the plunger comes into contact with a member such as a base, so that the opening area of the variable throttle portion does not increase further. ing.

  As described above, in this embodiment, an electromagnetic proportional throttle valve in which the plunger 4 is driven by the magnetic field generated in the coil 12 and the valve opening is adjusted by moving the shaft 5 coupled to the plunger 4 in the axial direction. 1, a valve seat 37 through which hydraulic oil circulates, a poppet 17 that throttles the flow of hydraulic oil between the valve seat 37, and the poppet 17 together with the shaft 5 in the valve opening direction (right direction in the figure). Stroke restricting means for restricting the stroke of the poppet 17 with respect to the valve seat 37 by bringing a part of the poppet 17 into contact with the poppet 17 when displaced is provided.

  Based on the above-described configuration, the components that determine the maximum valve opening are mainly the poppet 17 and the valve seat 37 in the electromagnetic proportional throttle valve 1, so that it may be affected by the dimensional accuracy of the components such as the shaft 5 as in the conventional device. In addition, the variation in the maximum flow rate generated for each product can be kept small, and the quality can be improved. Since other components such as the base 2 and the shaft 5 do not affect the maximum valve opening, it is possible to set a large dimensional tolerance in the central axis O direction, thereby reducing the cost of the product.

  In the present embodiment, a valve chamber 61 defined between the valve seat 37 and the poppet 17, a first bearing 7 and a second bearing 8 that slidably support the shaft 5 with the plunger 4 interposed therebetween, Plunger front chamber 74 defined between one bearing 7 and plunger 4, plunger back chamber 75 defined between plunger 4 and second bearing 8, plunger front chamber 74 and plunger back chamber 75. A plunger outer circumferential path 63 that communicates with the second bearing 8, a second bearing rear chamber 76 that is defined behind the second bearing 8 and is expanded and contracted by sliding of the shaft 5, and a plunger rear chamber 75 that penetrates the second bearing 8. A second bearing through passage 64 that communicates with the second bearing rear chamber 76; and a shaft through passage 65 that penetrates the shaft 5 in the axial direction and communicates with the valve chamber 61 and the second bearing rear chamber 76; The hydraulic fluid in the chamber 61 passes through the shaft passage 6 When was configured to be guided to the plunger behind chamber 75 and the second bearing behind chamber 76 through the second bearing through-passage 64.

  Based on the above configuration, the length of the path for the hydraulic oil contamination to reach the strong magnetic field B around the plunger 4 is lengthened and adheres to the surface of the magnetic material (base 2, plunger 4) constituting the strong magnetic field B. Can be suppressed. Thereby, the movable time during which the electromagnetic proportional throttle valve 1 operates stably can be extended.

  Since the second bearing back chamber 76 expanded and contracted by sliding of the shaft 5 communicates with the plunger back chamber 75 through the second bearing through passage 64, pressure fluctuation from the valve chamber 61 is caused by the second bearing back chamber. Even when the pressure is transmitted to 76, the pressure fluctuation in the second bearing back chamber 76 is transmitted to the plunger back chamber 75 through the second bearing through passage 64, and the second bearing 108 is pressured in the second bearing back chamber 76 and the plunger back chamber 75. Due to the difference, it can be prevented from moving from the normal position and falling off, and the pressure resistance of the electromagnetic proportional throttle valve 1 can be enhanced.

  Since the plunger outer circumferential path 63 is defined as an annular gap 55 around the plunger outer circumferential surface 41, the speed at which the plunger 4 moves can be increased by reducing the viscous resistance of the hydraulic oil applied to the plunger 4. As a result, the operation responsiveness of the electromagnetic proportional throttle valve 1 can be enhanced, and when the plunger 4 moves at a high speed, the contamination accumulated on the plunger 4 is removed, and the electromagnetic proportional throttle valve 1 caused by the contamination of the hydraulic oil. Can be prevented from malfunctioning.

  In the present embodiment, the base 2 constituting the magnetic path of the coil 12 is provided, and the stroke restricting means is configured to abut the base end surface 19 of the poppet 2 against the base 2, and the base end surface 19 of the poppet 2 contacts the base 2. A poppet internal / external communication passage 66 is provided in which the valve chamber 61 and the shaft through passage 65 communicate with each other in a contact state.

  Based on the above configuration, in the state where the base end surface 19 of the poppet 2 is in contact with the base end surface 58 and reaches the maximum valve opening degree, the shaft through passage 65 is not blocked by the poppet internal / external communication passage 66, and the hydraulic oil It flows between the valve chamber 61 and the shaft through passage 65, the shaft 5 and the plunger 4 move smoothly, and the operability of the electromagnetic proportional throttle valve 1 is maintained.

  The present invention is not limited to the above-described embodiment, and it is obvious that various modifications can be made within the scope of the technical idea.

  The electromagnetic proportional throttle valve of the present invention is useful for hydraulic equipment, other machines, and facilities.

DESCRIPTION OF SYMBOLS 1 Electromagnetic proportional throttle valve 2 Base 3 Sleeve 4 Plunger 5 Shaft 7 First bearing 8 Second bearing 9 Case 10 Coil assembly 17 Poppet 18 Poppet front end surface 19 Poppet base end surface 24 Spring 30 Variable throttle part 37 Valve seat 38 Valve hole 60 Notch Part 61 Valve chamber 63 Plunger outer circumferential path 64 Second bearing through path 65 Shaft through path 66 Poppet inner / outer communication path 74 Plunger front chamber 75 Plunger rear chamber 76 Second bearing rear chamber 77 Open edge (edge portion)

Claims (3)

The plunger is driven by the magnetic field generated in the coil,
An electromagnetic proportional throttle valve that adjusts the valve opening by moving the shaft coupled to the plunger in the axial direction,
A valve seat through which hydraulic fluid circulates;
A poppet that restricts the flow of hydraulic fluid between this valve seat and
Stroke regulating means for regulating a stroke of the poppet with respect to the valve seat by contacting a part of the poppet when the poppet is displaced together with the shaft in the valve opening direction;
An electromagnetic proportional throttle valve characterized by comprising: A valve chamber defined between the valve seat and the poppet;
A first bearing and a second bearing that slidably support the shaft across the plunger;
A plunger front chamber defined between the first bearing and the plunger;
A plunger back chamber defined between the plunger and the second bearing;
A plunger outer circumferential path communicating the plunger front chamber and the plunger back chamber;
A second bearing back chamber defined behind the second bearing and expanded and contracted by sliding of the shaft;
A second bearing through passage passing through the second bearing and communicating the plunger back chamber and the second bearing back chamber;
A shaft through passage that penetrates the shaft in the axial direction and communicates the valve chamber and the second bearing back chamber;
The electromagnetic oil according to claim 1, wherein the hydraulic oil in the valve chamber is guided to the plunger back chamber through the shaft through passage, the second bearing back chamber, and the second bearing through passage. Proportional throttle valve. Comprising a base constituting the magnetic path of the coil;
The stroke restricting means is configured to abut the base end surface of the poppet against the base,
3. The electromagnetic proportional throttle according to claim 1, further comprising a poppet internal / external communication passage through which the valve chamber communicates with the shaft through passage in a state in which the base end surface of the poppet is in contact with a base. valve.

Images