JP4217585B2 - Solenoid proportional valve - Google Patents

Description

  The present invention relates to an electromagnetic proportional valve, and more particularly to an electromagnetic proportional valve used in an analyzer or the like that needs to perform a very small flow rate control with high accuracy.

  An electromagnetic proportional valve is known as a flow control valve used in an analyzer such as chromatography. As this type of electromagnetic proportional valve, a valve housing, a valve housing having a valve port, and a linear electromagnetic actuator including a plunger movably provided in an axial direction in a plunger tube attached to the valve housing; A valve body provided in the valve chamber, connected to the plunger and changing an opening degree of the valve port according to an axial direction of the plunger; and between a connection body of the plunger and the valve body and the valve housing. There is a built-in leaf spring, and the opening / closing position of the valve body is determined by an equilibrium relationship between the electromagnetic force generated by the electromagnetic actuator and the spring force of the leaf spring, thereby controlling the flow rate (for example, Patent Documents 1 and 2).

  In the electromagnetic proportional valve described above, in order to perform stable and highly accurate flow rate control for each individual flow rate control, the leaf spring incorporated in the electromagnetic proportional valve has a spring load characteristic applied to the connection body. It is important that there is no variation and that the spring load applied to the coupling body by the leaf spring during the flow rate control operation does not fluctuate irregularly and has continuity.

  On the other hand, in the conventional electromagnetic proportional valve, the leaf spring is fixed to the valve housing by using a fixing ring on the outer edge side and fixedly coupled to the valve body by caulking or the like on the inner edge side. There may be variations in the initial spring load characteristics due to variations in the fixed state (assembly error).

  In addition, since there is an inevitable radial clearance between the plunger tube and the plunger so that the plunger can move in the axial direction, it is inevitable that the plunger moves irregularly in the radial direction during the flow control operation. The load due to the movement in the radial direction acts on the leaf spring in the lateral direction (diameter direction), and accordingly, the spring load that the leaf spring applies to the coupling body of the plunger and the valve body fluctuates irregularly. This becomes remarkable when the electromagnetic proportional valve is used in a vibrating atmosphere and the plunger is vibrated from the outside.

  Further, if the plunger tube is inclined with respect to the central axis due to the mounting error of the plunger tube with respect to the valve housing, a lateral load acts on the leaf spring as the plunger moves in the axial direction, and the leaf spring acts as the connecting body. The spring load characteristics given to the fluctuate.

For these reasons, in the conventional electromagnetic proportional valve, the flow rate control characteristics vary from one individual to another, and stable and highly accurate flow rate control cannot be performed.
JP 2002-71045 A JP 2002-357280 A

  The problem to be solved by the present invention is to obtain an electromagnetic proportional valve that performs stable and highly accurate flow rate control without variation in flow rate control characteristics among individuals.

  An electromagnetic proportional valve according to the present invention includes a valve housing having a valve chamber and a valve port, a linear electromagnetic actuator including a plunger movably disposed in an axial direction in a plunger tube attached to the valve housing, A valve body provided in a valve chamber and connected to the plunger, the opening degree of the valve port being changed by the movement of the plunger in the axial direction, and the plunger and the connection body of the valve body and the valve housing are incorporated between the valve body and the valve housing; In an electromagnetic proportional valve that controls the flow rate by determining the opening / closing position of the valve body by an equilibrium relationship between the electromagnetic force generated by the electromagnetic actuator and the spring force of the leaf spring, Is an annular shape, loosely fitted to the outer periphery of the connecting body, engaged with the valve housing on the outer peripheral edge side, and formed on the outer periphery of the connecting body on the inner peripheral edge side. A radial clearance A is set between the plunger tube and the plunger by the difference between the inner diameter of the plunger tube and the outer diameter of the plunger, and the outer diameter of the coupling body. The radial clearance B is set between the connecting body and the leaf spring by the difference between the inner diameter of the leaf spring and the leaf spring, and the magnitude relationship between the radial clearance A and the radial clearance B is A <B. It is.

  In the electromagnetic proportional valve according to the present invention, preferably, the valve housing has a large-diameter portion that forms a step end surface facing the flange end surface at a radially outward position of the coupling body, and the leaf spring includes: In the state where it is stored in the large-diameter portion and its outer peripheral edge abuts and engages with the step end surface, it is sandwiched between the step end surface and the flange end surface.

  In this case, preferably, a radial clearance C is set between the leaf spring and the large diameter portion by a difference between an outer diameter of the leaf spring and an inner diameter of the large diameter portion, and the radial clearance A, The magnitude relationship between the radial clearance B and the radial clearance C is C <A <B and (BC)> A.

  In the electromagnetic proportional valve according to the present invention, the leaf spring is not fixedly connected to the connection body between the plunger and the valve body, but only abuts and engages with the flange end surface of the connection body. There is no cause of variation (assembly error) in the fixed state of the plunger, and the radial movement of the plunger does not act on the leaf spring.

  Moreover, since the radial clearance B between the coupling body and the leaf spring is larger than the radial clearance A between the plunger tube and the plunger, even if the plunger moves in the radial direction in the plunger tube, the coupling body and the plate There is no irregular contact with the spring in the radial direction.

  As a result, in the electromagnetic proportional valve according to the present invention, there is no variation in the spring load characteristic that the leaf spring gives to the connecting body, and the spring load that the leaf spring gives to the connecting body does not fluctuate irregularly. . As a result, there is no variation in the flow rate control characteristic for each individual, and stable and highly accurate flow rate control can be performed.

  One embodiment of an electromagnetic proportional valve according to the present invention will be described with reference to FIGS.

  As shown in FIG. 1, the electromagnetic proportional valve has a valve housing 11. The valve housing 11 includes a housing body 12 and a lid member 14 fixed to the housing body 12 by a screw portion 13. The housing body 12 and the lid member 14 define a valve chamber 16 that is hermetically sealed by an O-ring 15. A cylindrical filter member 17 made of a porous material or the like is disposed in the valve chamber 16 via an O-ring 17.

  A first input / output port 18 and a second input / output port 19 are formed in the housing body 12. A sleeve-shaped valve seat member 20 is fixed to the housing body 12 concentrically with the filter member 17. The valve seat member 20 communicates with the second inlet / outlet port 19 through an internal passage 21, has a valve port 22 concentric with the filter member 17 in the upper portion, and has a valve seat surface 23 on the upper surface. The first inlet / outlet port 18 communicates directly with the valve chamber 16.

  A linear electromagnetic actuator 31 is attached to the upper portion of the valve housing 11. The electromagnetic actuator 31 has a cylindrical plunger tube 32 fixed to the lid member 14 by brazing. The plunger tube 32 is fitted on and inserted into a central through hole 24 formed in the lid member 14 at the lower end side, and is arranged on the concentric shaft with the filter member 17. In FIG. 1, reference numeral 25 indicates a brazed portion of the plunger tube 32.

  A suction element 33 that also serves as a plug is fitted and fixed to the upper end side of the plunger tube 32. On the outside of the plunger tube 32, an electromagnetic coil member 37 including an outer rod 34, a bobbin 35, a winding 36 and the like is fixedly attached by a retaining ring 38.

  A plunger 39 is provided in the plunger tube 32 so as to be movable in the axial direction (valve opening / closing direction). A holder receiving hole 40 is formed on the lower end of the plunger 39 on the concentric shaft with the filter member 17, and a cylindrical holder member 41 is fitted and fixed on the concentric shaft with the filter member 17 in the holder receiving hole 40. Has been.

  As shown in FIG. 2, the holder member 41 has an annular inner peripheral flange 42 and an annular outer peripheral flange 43 at the lower end, and a valve body 44 and a stem inside. The member 45 is accommodated.

  The valve body 44 is prevented from coming off by engagement with the inner peripheral flange 42 and is connected to the plunger 39 via the holder member 41. The valve body 44 opposes the valve seat surface 23 with a lower bottom surface 46, and performs opening / closing and opening adjustment of the valve port 22 by movement in the axial direction (vertical direction).

  On the lower bottom surface side of the lid member 14, a circular large-diameter portion 26 for accommodating a leaf spring is formed on the concentric shaft with the filter member 17. An annular leaf spring 51 is disposed in the large diameter portion 26. The leaf spring 51 is loosely fitted to the outer periphery of the holder member 41, engages with the downward annular step end surface 27 that forms the lower bottom surface of the large-diameter portion 26 on the upper surface of the outer peripheral edge 52, and the outer peripheral edge 53. Is in abutment engagement with an upward annular flange end surface 47 formed by the upper surface of the outer peripheral flange 43.

  As a result, the leaf spring 51 is sandwiched between the step end surface 27 and the flange end surface 47 in an elastically deformed state in accordance with the difference in the axial position between the step end surface 27 and the flange end surface 47, and the valve body 44. The connecting body of the holder member 41 including the plunger 39 and the plunger 39 is biased downward, that is, in the valve closing direction. The leaf spring 51 is not fastened and fixed to the valve housing 11 side, neither the valve body 44 side nor the plunger 32 side.

  The electromagnetic actuator 31 is energized by energizing the electromagnetic coil member 37, generates a magnetic attractive force (electromagnetic force) corresponding to the coil current value controlled by duty ratio control or the like in the attractive force 33, and the valve The coupling body of the holder member 41 including the body 44 and the plunger 39 is driven upward, that is, in the valve opening direction.

  Thereby, the opening / closing position of the valve body 44 is determined by the equilibrium relationship between the electromagnetic force generated by the electromagnetic actuator 31 and the spring force of the leaf spring 51, and flow control is performed.

  In the electromagnetic proportional valve according to the present invention, the radial clearance A is set between the plunger tube 32 and the plunger 39 by the difference between the inner diameter Da of the plunger tube 32 and the outer diameter Db of the plunger 39, and the outer diameter Dc of the holder member 41. A radial clearance B is set between the holder member 41 and the leaf spring 51 by the difference between the inner diameter Dd of the leaf spring 51 and the leaf spring 51. A radial clearance C is set between the leaf spring 51 and the large diameter portion 26 by the difference between the outer diameter De of the leaf spring 51 and the inner diameter Df of the large diameter portion 26.

  The magnitude relationship among the radial clearance A, the radial clearance B, and the radial clearance C is C <A <B and (BC)> A.

  The radial clearance A may be set to a minimum value at which the plunger 39 can move in the axial direction within the plunger tube 32 without hindrance.

  The radial clearance B is such that even if the plunger 39 moves in the radial direction within the range of the radial clearance A within the plunger tube 32, the plunger 39 has a central axis line due to an attachment error (straight error) of the plunger tube 32 to the valve housing 11. Even if it moves in the radial direction with respect to X, the outer peripheral surface of the holder member 41 integral with the plunger 39 is set to an appropriate value that does not contact the inner peripheral edge of the leaf spring 51.

  The radial clearance C is a gap necessary for disposing the leaf spring 51 in the large diameter portion 26 in a fitting state where the leaf spring 51 is not tightly fitted to the large diameter portion 26.

  As described above, the leaf spring 51 is not fixedly connected to the connection body between the plunger 39 including the holder member 41 and the valve body 44, but merely abuts and engages with the flange end surface 53 of this connection body. In addition, there is no cause for variation (assembly error) in the fixed state between the coupling body and the leaf spring 51, and the radial movement of the plunger 39 does not act on the leaf spring 51. Further, since the leaf spring 51 only abuts and engages with the step end surface 27 on the valve housing 11 side, a fastening error of the leaf spring 51 with respect to the valve housing 11 does not occur.

  In addition, since the radial clearance B between the connecting body and the leaf spring 51 is larger than the radial clearance A between the plunger tube 32 and the plunger 39, the plunger 39 is within the plunger tube 32 during the flow rate control operation. Even if it moves in the radial direction, the holder member 41 and the leaf spring 51 do not contact irregularly in the radial direction. Further, even if the plunger 39 moves in the radial direction with respect to the central axis X due to the straightness error of the plunger tube 32 with respect to the valve housing 11, the holder member 41 and the leaf spring 51 do not contact in the radial direction.

  As a result, in the electromagnetic proportional valve according to the above-described embodiment, there is no variation in the spring load characteristic that the leaf spring 51 gives to the connecting body of the plunger 39 and the valve body 44, and the leaf spring 51 is connected to the plunger 39. The spring load applied to the connection body with the valve body 44 does not fluctuate irregularly. As a result, there is no variation in the flow rate control characteristic for each individual, and stable and highly accurate flow rate control can be performed.

It is a longitudinal cross-sectional view which shows one Embodiment of the electromagnetic proportional valve by this invention. It is a longitudinal cross-sectional view which expands and shows the principal part of one Embodiment of the electromagnetic proportional valve by this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 Valve housing 16 Valve chamber 22 Valve port 26 Large diameter part 31 Electromagnetic actuator 32 Plunger tube 39 Plunger 44 Valve body 51 Leaf spring

Claims (3)

A valve housing having a valve chamber and a valve port;
A linear electromagnetic actuator including a plunger movably provided in an axial direction in a plunger tube attached to the valve housing;
A valve body that is provided in the valve chamber and connected to the plunger, and changes an opening degree of the valve port by an axial movement of the plunger;
A leaf spring incorporated between the plunger and the coupling body of the valve body and the valve housing;
In the electromagnetic proportional valve that controls the flow rate, the opening and closing position of the valve body is determined by the equilibrium relationship between the electromagnetic force generated by the electromagnetic actuator and the spring force of the leaf spring.
The leaf spring is annular and loosely fits on the outer periphery of the connecting body, engages with the valve housing on the outer peripheral edge side, and abuts against a flange end surface formed on the outer periphery of the connecting body on the inner peripheral edge side. Engaging
A radial clearance A is set between the plunger tube and the plunger by the difference between the inner diameter of the plunger tube and the outer diameter of the plunger, and the difference between the outer diameter of the coupling body and the inner diameter of the leaf spring is set by the difference between the plunger tube and the plunger. A radial clearance B is set between the coupling body and the leaf spring,
The magnitude relationship between the radial clearance A and the radial clearance B is A <B.
Proportional solenoid valve.   The valve housing has a large-diameter portion that forms a stepped end surface facing the flange end surface at a radially outward position of the coupling body, and the leaf spring is accommodated in the large-diameter portion and has an outer peripheral edge side. The electromagnetic proportional valve according to claim 1, wherein is sandwiched between the step end surface and the flange end surface in a state of being in contact with and engaging with the step end surface.   A radial clearance C is set between the leaf spring and the large diameter portion by a difference between an outer diameter of the leaf spring and an inner diameter of the large diameter portion, and the radial clearance A, the radial clearance B, and 3. The electromagnetic proportional valve according to claim 2, wherein the magnitude relationship of the radial clearance C is C <A <B and (BC)> A.

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