JP6472637B2 - Motorized valve - Google Patents

Description

  The present invention relates to a bearing structure for a valve shaft applied to, for example, a stepping motor drive type electric valve.

  For example, in an electric valve driven by a stepping motor used as a variable throttle valve or a flow control valve, the rotational movement of the electric motor is converted into a linear movement by a screw feed mechanism composed of a male screw and a female screw. The valve is opened and closed by moving the valve body in the axial direction with respect to the valve seat.

By the way, in general, in a motor-operated valve, it is not preferable to transmit the rotation of the motor to the valve body because it leads to wear of the valve seat.
Therefore, in Patent Document 1 (Japanese Patent Laid-Open No. 2003-148463), as shown in FIG. 4, a cylindrical valve that moves in the axial direction integrally with the valve body 17 by being fixed to the valve body 17. Between the lower surface of the ceiling portion 21 of the guide 18 and the flange 41b provided at the lower end portion of the valve shaft 41 that moves in the axial direction while rotating, a highly slippery resin washer, a washer of a highly slippery resin coating, or the like The sliding member 26 is installed so that the rotational force of the valve shaft 41 is not transmitted to the valve body 17.

  However, in the sliding member 26 such as a high-slip resin washer or a metal washer coated with a high-slip resin, for example, when the use period is extended, the washer is worn or deformed. There is a problem that the rotational force of 41 is transmitted to the valve body 17.

  On the other hand, as the sliding member 26, a commercially available thrust bearing is also used instead of using a highly slipping resin washer or a highly slipping resin coating washer.

  However, a commercially available thrust bearing has a structure in which a ball as a rolling element is sandwiched vertically in FIG. 4 between two plate members in which hemispherical recesses are formed. The ball cannot move in any direction inside or outside the diameter.

  Therefore, when the valve shaft 41 is incorporated with the shaft core deviated from the valve body 17 in the valve shaft bearing structure using a commercially available thrust bearing as the sliding member 26, the deviation is reduced. As a result, there is a problem in that the valve body 17 comes into contact with the valve seat in a tilted posture, and the valve seat is worn.

However, simply replacing the thrust bearing 26 with a high-slip washer,
On the other hand, in Patent Document 2 (Japanese Patent Laid-Open No. 2014-43949), a radial rolling bearing is installed as the sliding member 26.

When a radial rolling bearing is installed as in Patent Document 2, for example, compared with a case where a washer is used, wear and deformation at the bearing portion are less likely to occur.
However, in the case of radial rolling bearings, there is no radial backlash. As a result, when the valve element 17 closes the valve seat, the centripetal force is lost and the valve closing function is impaired.

Japanese Patent Laid-Open No. 2003-148643 JP 2014-43949 A

  In view of such a conventional situation, the present invention prevents transmission of the rotational force of the valve shaft based on the rotational force of the motor to the valve body, and wears the valve seat even when the shaft center of the valve shaft is displaced. In addition, an object of the present invention is to provide a bearing structure for a valve shaft that can set a good valve function and can suppress an increase in the number of parts.

The valve shaft bearing structure according to the present invention for achieving the above object is as follows:
A flange formed on a valve shaft that is inserted in a cylindrical valve guide that moves in the axial direction integrally with the valve body by being fixed to the valve body, and the valve guide; A valve shaft bearing structure comprising:
A through hole is formed in the ceiling of the cylindrical valve guide,
A plurality of balls that are movable in the radial direction are arranged between the ceiling portion and the flange portion.

  In the present invention having such a configuration, the ball installed on the bearing portion can move in the radial direction. Therefore, even if the valve shaft is displaced, the displacement of the shaft core is used to move the ball. Can be tolerated. Thereby, abrasion of a valve seat can be prevented.

In the present invention, it is preferable that a holder for restricting the drop of the ball is disposed between the ball and the valve guide.
If the holder is thus arranged, the ball can be reliably prevented from falling.

  Furthermore, in the present invention, the holder is formed in a ring shape, and the ring holder has an outer end surface of the flange portion of the valve shaft in a state where the valve shaft and the valve guide are coaxial. It is preferable that the width is larger than the clearance between the valve guide and the inner peripheral surface, and a part of the upper surface of the flange portion is abutted.

If it is such a holder, positioning with respect to a bearing part is favorable.
In the present invention, it is preferable that the ring-shaped holder has recesses formed at predetermined intervals, and the balls are accommodated in the recesses.
With such a configuration, a minimum number of balls can be efficiently arranged at predetermined intervals.

Furthermore, in the present invention, a cylindrical portion having a smooth outer peripheral surface is formed on the base side of the valve shaft where the flange portion is formed, and the length of the cylindrical portion is such that the ball can come into contact therewith. It is preferable that it is set.
In this way, if the contact portion of the ball is formed smoothly, the rolling property of the ball is good.

Further, in the present invention, it is preferable that a washer member is installed between the ball and the ceiling portion.
Thus, if the washer member is installed between the ball and the ceiling portion, inadvertent movement of the ball toward the ceiling portion side can be prevented.

In the present invention, the lower protrusions may be formed at predetermined intervals on the lower surface of the ceiling portion.
In this way, if the lower protrusion is formed on the lower surface of the ceiling portion of the valve guide, the valve guide can press the washer member by point contact by the lower protrusion.

  According to the bearing structure of the valve shaft according to the present invention, since the ball installed on the bearing portion can move in the radial direction, the valve shaft can be moved in the radial direction even if the axis of the valve shaft is displaced. The valve seat can be prevented from being worn. Moreover, the fall of the ball can be prevented by the holding portion.

Furthermore, according to the bearing structure of the valve shaft according to the present invention, the seating stability with respect to the valve seat is improved, so that the durability of the valve portion including the valve body and the valve seat can be improved.
Further, according to the bearing structure of the valve shaft of the present invention, it can be applied to any valve, and the number of parts can be reduced when the bearing structure is provided.

FIG. 1 is a cross-sectional view of a motor-operated valve employing a valve shaft bearing structure according to an embodiment of the present invention. FIG. 2 is a partially enlarged sectional view of FIG. 3A is a perspective view of a valve shaft assembly which is a component of the bearing structure shown in FIG. 1, and FIG. 3B is a side view of FIG. FIG. 4 is a cross-sectional view of a conventional bearing structure disclosed in Japanese Patent Laid-Open No. 2003-148643.

Hereinafter, preferred embodiments (examples) of the present invention will be described with reference to the drawings.
FIG. 1 is a cross-sectional view showing a motor-operated valve employing a valve shaft bearing structure according to an embodiment of the present invention.

In the present specification, “upper” or “lower” is defined in the state of FIG.
In the motor-operated valve 10, the valve body 30 is integrally connected to a lower end portion on the opening side of a case 60 made of a non-magnetic material and having a cylindrical cup shape by welding.

  The valve body 30 is a press-formed product manufactured by pressing a stainless steel plate, and defines a valve chamber 11 therein. The valve body 30 includes a first pipe joint 12 made of copper that directly communicates with the valve chamber 11, a valve seat member 14 having a central (center position) arrangement made of stainless steel or sintered metal that defines the valve port 13, and A copper second pipe joint 15 communicating with the valve chamber 11 via the valve port 13 is fixedly mounted by welding, brazing or the like. The valve seat member 14 is a separate member from the valve body 30, but the valve seat member 14 may be formed directly on the valve body 30.

A rotatable rotor 2 is accommodated in the inner periphery of the case 60.
On the outer periphery of the case 60, a stator including a yoke, a bobbin, and a coil (not shown) is disposed, and the rotor 2 and the stator constitute a stepping motor.

  A guide support 52 is fixed to the ceiling surface of the case 60. The guide support body 52 has a cylindrical portion 53 and an umbrella-shaped portion 54 formed on the upper end side of the cylindrical portion 53, and the whole is integrally formed by pressing. The umbrella-shaped portion 54 is formed in substantially the same shape as the inside of the top portion of the case 60.

  The cylindrical portion 53 of the guide support body 52 is concentrically installed with the rotor 2 and is suspended from the center of the ceiling portion of the case 60 in the axial direction. In addition, a positioning hole 57 is press-formed at the lower end of the cylindrical portion 53, and a cut-and-raised piece 58 exists at the back of the positioning hole 57.

  The cylindrical portion 53 of the guide support 52 is provided with a spiral guide 59 formed in a coil spring shape by a wire having springiness so as to surround the outer periphery of the cylindrical portion 53. The spiral guide 59 has a stopper 62 that extends in the axial direction at the lower end.

  The spiral guide 59 abuts on a valve opening stopper projection 56 formed in the middle of the guide support 52 on the upper end side, and the stopper portion 62 on the lower end portion is inserted and fitted into the positioning hole 57 so that the tip of the stopper portion 62 is inserted. Is cut and raised by the elastic force of the spiral guide 59 and abuts against the piece 58.

  Thus, the spiral guide 59 is sandwiched between the valve opening stopper projection 56 and the positioning hole 57 by the axial spring load, and the mounting position is determined without rattling.

A movable stopper member 63 is rotatably engaged with the spiral guide 59. The movable stopper member 63 is shaped like a one-turn coil spring.
When the movable stopper member 63 is kicked by the rotation of the rotor 2, the movable stopper member 63 is guided by the spiral guide 59 while rotating, and performs a spiral motion, and moves in the axial direction of the spiral guide 59. When the movable stopper member 63 abuts against the stopper portion 62 of the spiral guide 59, the leftward rotation further downward is stopped, and the origin position of the rotor 2 is mechanically set based on the valve closing reference. Further, when the movable stopper member 63 abuts against the valve opening stopper projection 56, further clockwise rotation is stopped and the valve opening (full opening) position is mechanically set.

  A cylindrical member 65 that also serves as a guide for the valve shaft 41 is fitted in the cylindrical portion 53 of the guide support 52. The cylindrical member 65 is made of a material containing a lubricant or a surface-treated part made of metal or synthetic resin, and rotatably holds the valve shaft 41.

  On the other hand, a cylindrical valve shaft holder 6 having a through hole 6 h formed therein is fixed to the upper end portion of the valve body 30 so as not to rotate relative to the valve body 30. The valve shaft holder 6 has a function of suppressing the inclination of a valve shaft 41 described later.

  The valve shaft holder 6 includes an upper cylindrical small diameter portion 6a, a lower cylindrical large diameter portion 6b, a fitting portion 34 accommodated in an inner peripheral side portion of the valve body 30, and a ring-shaped flange portion. The flange portion 6f is fixed to the upper opening end of the valve body 30 by welding or the like.

  Further, a pressure equalization hole for equalizing the pressure between the valve shaft holder chamber 83 formed inside the valve shaft holder 6 and the outer space of the valve shaft holder 6 is formed in the side surface of the cylindrical large-diameter portion 6 b of the valve shaft holder 6. 51 is drilled. By providing such a pressure equalizing hole 51, the moving operation of the valve shaft holder 6 is performed smoothly.

Further, in the valve shaft holder 6, a female thread portion 6d is formed downward from the upper opening 6g of the cylindrical small diameter portion 6a to a predetermined depth.
On the other hand, a valve shaft 41 is disposed through the shaft core portion of the rotor 2 via a bush member 33. The valve shaft 41 rotates integrally with the rotor 2. A male screw portion 41 a is formed on the outer peripheral portion on the upper side of the valve shaft 41.

A screw feed mechanism A is configured by the male screw portion 41 a formed on the outer periphery of the valve shaft 41 and the female screw portion 6 d formed on the inner periphery of the valve shaft holder 6.
In addition, on the lower end side of the valve shaft 41 and inside the cylindrical large diameter portion 6 b of the valve shaft holder 6, the cylindrical valve guide 18 slides with respect to the through hole 6 h of the valve shaft holder 6. Arranged to be possible. The valve guide 18 is bent at a substantially right angle on the ceiling 21 side by press molding. A through hole 18a is formed in the ceiling portion 21, and a lower protrusion 18d is formed on the lower surface of the ceiling surface. The lower protrusions 18d may be continuous in the circumferential direction, or may be formed at predetermined intervals. If such a downward projection 18d is formed, even if a round having a curvature is formed at the joint portion between the inner periphery of the side wall of the valve guide 18 and the ceiling surface 21, the downward projection 18d avoids the round. And the diameter of the washer 70 can be increased.

On the other hand, a flange 41 b is formed at the lower end of the valve shaft 41. The upper surface and the lower surface of the flange portion 41b are flat surfaces, but it is only necessary that the upper surface, which is the surface with which the ball abuts, be formed flat.
Therefore, in this embodiment, a cylindrical portion 41d having a smooth outer peripheral surface is provided on the base side where the flange portion 41b of the valve shaft 41 is formed. The length V of the cylindrical portion 41d from the upper surface of the flange portion 41b is set to be longer than the radius of the ball 76 so that the ball 76 can come into contact with the cylindrical portion 41d.

  The flange 41b of the valve shaft 41 is fitted in the through hole 18a of the valve guide 18 so as to be rotatable with respect to the valve guide 18 and displaceable in the radial direction. Further, since the flange 41b has a larger diameter than the through hole 18a of the valve guide 18, the valve shaft 41 is prevented from coming off.

  Since the valve shaft 41 and the valve guide 18 are movable in the radial direction with respect to each other, the valve guide 18 and the valve guide 18 and the valve shaft 41 are not required to have a high degree of concentric mounting accuracy with respect to the arrangement positions of the valve shaft holder 6 and the valve shaft 41. Concentricity between the valve body 17 and the valve seat member 14 is obtained.

The ceiling portion 21 of the valve guide 18 and the flange portion 41b of the valve shaft 41 form a thrust surface, and a bearing structure that is a main portion of the present embodiment is formed between the thrust surfaces.
Further, a compressed valve spring 27 and a spring receiver 35 are accommodated in the valve guide 18. The lower end of the valve guide 18 is fixed to the base portion side outer peripheral surface of the valve body 17 by welding or the like. The valve body 17 has a needle valve portion 19 that quantitatively increases or decreases the opening and closing of the valve port 13 and the effective opening area by moving in the axial direction (vertical direction) relative to the valve seat member 14.

Below, the bearing structure of the valve shaft comprised between the collar part 41b of the valve shaft 41 which is the principal part of this invention, and the valve guide 18 is demonstrated.
The valve shaft bearing structure according to this embodiment is configured between the flange 41b of the valve shaft 41 and the valve guide 18, as shown in an enlarged manner in FIG.

  That is, the washer 70 is installed on the ceiling portion 21 of the valve guide 18. The washer 70 is preferably a metal washer having a highly slippery surface, a highly slippery resin washer such as a fluororesin, or a metal washer having a highly slippery resin coating. A through hole 70a is formed in the central portion of the washer 70, and the flange portion 41b of the valve shaft 41 can be freely rotated with respect to the valve guide 18 and can be displaced in the radial direction in the through hole 70a. It is penetrated.

Further, as shown in FIGS. 3 (A) and 3 (B), a ring-shaped holder 72 is placed concentrically on one side surface of the washer 70.
The ring-shaped holder 72 has a through hole 72 a having the same diameter as the through hole 70 a of the washer 70. The ring-shaped holder 72 is formed with a plurality of ball receiving recesses 74 that open toward the radially inner side at predetermined intervals. That is, in this embodiment, three are formed at intervals of 120 degrees.

  In each ball housing recess 74 of the ring-shaped holder 72, balls 76 are housed as rolling elements, respectively. The diameter of the ball 76 is such that the outer peripheral surface of the ball partially bulges from the recess 74 in the axial direction. The ball 76 may be made of metal or resin, but if it is made of resin, it is preferably hard. Further, from the viewpoint of wear resistance, when the ball 76 is made of metal, the washer 70 is preferably made of metal.

  Thus, since the ball 76 is slightly movable radially inward in the ball receiving recess 74 of the ring-shaped holder 72, the valve shaft 41 and the valve guide 18 can be displaced in the radial direction. Become. As a result, with respect to the arrangement position of the valve shaft 41 determined by the mounting accuracy of the valve shaft holder 6 and the like, and the arrangement position of the valve guide 18 determined by the mounting accuracy of the valve shaft holder 6 and the like, a high degree of concentric mounting accuracy is obtained at the time of assembly. Without being required, the concentricity of the valve guide 18 and the valve body 17 and the valve seat member 14 can be improved.

In the bearing structure of the valve shaft according to the present embodiment, the ball 76 is accommodated in the ring-shaped holder 72 as described above, and is incorporated in the motor-operated valve 10 in this state.
With this structure, the valve shaft 41 and the valve guide 18 are connected to each other in a relatively rotatable manner by a bearing assembly 80 including a washer 70, a ring-shaped holder 72, and a plurality of balls 76. The valve shaft 41 can be lifted (moved in the valve opening direction) in such a manner that the valve shaft 41 can rotate with respect to the valve guide 18 with low frictional resistance.

With this structure, the valve shaft 41, the bearing member 80, the valve spring 27, and the spring receiver 35 can rotate with a low frictional resistance with respect to the connection body of the valve body 17 and the valve guide 18. In addition, since the ball 76 can move slightly in the radial direction, even if the shaft centers of the valve shaft 41 and the valve body 17 are displaced, the displacement of the shaft core can be absorbed. Abrasion of the sheet can be prevented.
The bearing structure of the valve shaft of the motor-operated valve according to the present invention has been described above. The operation of the motor-operated valve will be described below.

  In the motor-operated valve 10 having the above-described configuration, when a drive pulse signal is given to the stepping motor, the rotor 2 rotates according to the number of pulses, and the valve shaft 41 rotates accordingly, and the male screw portion 41a of the valve shaft 41 is rotated. The valve shaft 41 moves in the axial direction while rotating by the screw feed mechanism A composed of the female screw portion 6d of the valve shaft holder 6 fixedly arranged.

  The upward movement (movement in the valve opening direction) of the valve shaft 41 is transmitted to the valve guide 18 by the contact of the spring receiver 35, the flange 41b, the ring-shaped holder 72, the washer 70, and the ceiling portion 21, and the valve guide 18 and The valve body 17 moves upward.

  In this upward movement, the valve shaft 41 can be rotated by sliding relative to the valve guide 18 with a low frictional resistance by the bearing assembly 80 shown in FIG. Further, even when the frictional resistance between the valve guide 18 and the through hole 6h of the valve shaft holder 6 is large, the valve shaft 41 can rotate and generate thrust to move the valve guide 18 and the valve body 17 upward.

  The downward movement (movement in the valve closing direction) of the valve shaft 41 is also transmitted to the valve guide 18 by the contact of the spring receiver 35, the flange portion 41b, the ring-shaped holder 72, the washer 70, the ceiling portion 21, and the valve spring 27. The guide 18 and the valve body 17 move downward.

  Even in this downward movement, the valve shaft 41 can slide and rotate relative to the valve guide 18 with a low frictional resistance by the bearing assembly 80 shown in FIG. 3, and the valve guide 18 and the valve shaft holder 6 can be rotated. Even when the frictional resistance with the through-hole 6h is large, the rotor 2 can rotate and generate thrust to move the valve guide 18 and the valve body 17 downward. Thereby, even if the outer diameter of the valve guide 18 is large, the driving force required for closing the valve is small, and the valve can be closed with low power.

  Note that, regardless of whether the valve is open or closed, the valve spring 27 in the valve guide 18 is rotated together with the valve shaft 41 by engagement with the spring receiver 35, and the spring receiver 35 is against the back surface of the valve body 17. The spring receiver 35 is made of a highly slippery resin and has a hemispherical contact portion 35a that is in contact with the flange portion 41b in a substantially point contact state, so that the spring receiver 35 and the flange portion 41b are rotated. A large frictional resistance is not generated between the valve spring 27 and the valve spring 27 is not twisted.

Further, the valve shaft 41 is supported by the valve shaft holder 6 at the lower end side by the male screw portion 41a and supported by the bulging portion 65a of the tubular member 65 at the upper end side, and is supported at both ends. The rotational vibration of the rotor 2 is reduced as compared with a certain case. Thereby, the operation noise at the time of valve opening / closing is reduced.
As mentioned above, although one Example of this invention was described, this invention is not limited to the said Example at all.

  For example, in the above embodiment, three balls 76 are accommodated in the ring-shaped holder 72. Instead, a large number of balls 76 are arranged so as to surround the peripheral surface of the valve shaft 41. You can also. In this case, even if the ball receiving recess 74 is not formed, it may be simply formed in an annular shape.

  That is, as shown in FIG. 2 and FIG. 3, the holder 72 has the outer peripheral surface 41 c of the flange 41 b of the valve shaft 41 and the valve guide 18 in a state where the valve shaft 41 and the valve guide 18 are coaxial. What is necessary is just the magnitude | size which has the width | variety T larger than the clearance S between the inner peripheral surfaces 18b, and the inner peripheral side of the holder 72 is mounted in a part of the collar part 41b.

  Further, the valve shaft 41 may be attached to the case 60 with other structures. Furthermore, in the above-described embodiment, an example is shown in which the motorized valve in which the rotor 2 is rotated by a stepping motor has been shown. However, the present invention can also be applied to a valve driven by other means.

2 Rotor 4 Valve shaft 6 Valve shaft holder 6a Tubular small diameter portion 6b Tubular large diameter portion 6d Female thread portion 6f Flange portion 6g Upper opening 6h Through hole 10 Motorized valve 11 Valve chamber 12 First pipe joint 13 Valve port 14 Valve seat member 15 Second pipe joint 17 Valve body 18 Valve guide 18d Lower projection 18a Through hole 18b Inner peripheral surface 19 Needle valve portion 21 Ceiling portion 26 Thrust bearing 27 Valve spring 30 Valve body 33 Bush member 34 Fitting portion 35a Hemisphere Abutting portion 41 Valve shaft 41a Male thread portion 41b Gutter portion 41c Outer peripheral surface 41d Cylindrical portion 51 Pressure equalizing hole 52 Guide support 53 Cylindrical portion 54 Umbrella portion 56 Valve opening stopper projection 57 Positioning hole 58 Cut and raised piece 59 Spiral Guide 60 Case 62 Stopper 63 Movable stopper member 65 Cylindrical member 65a Swelling part 70 Washer 70a Through-hole 72 Ring-shaped holder 72a Hole 74 ball receiving recess 76 ball 80 bearing assemblies 83 the valve shaft holder chamber A screw feed mechanism S width V Length

Claims (7)

A flange formed on a valve shaft that is inserted in a cylindrical valve guide that moves in the axial direction integrally with the valve body by being fixed to the valve body, and the valve guide; A valve shaft bearing structure comprising:
A through hole is formed in the ceiling of the cylindrical valve guide,
A bearing structure for a valve shaft, wherein a plurality of radially movable balls are disposed between the ceiling portion and the flange portion.   The bearing structure for a valve shaft according to claim 1, wherein a holder for restricting the drop of the ball is disposed between the ball and the valve guide.   The holder is formed in a ring shape, and in the state where the valve shaft and the valve guide are on the same axis, the ring holder has an outer end surface of the flange portion of the valve shaft and an inner periphery of the valve guide. The valve shaft bearing structure according to claim 2, wherein the bearing structure has a width larger than a clearance with the surface and a part of the upper surface of the flange portion.   4. The bearing structure for a valve shaft according to claim 3, wherein recesses are formed at predetermined intervals in the ring-shaped holder, and the balls are accommodated in the recesses.   A cylindrical portion with a smooth outer peripheral surface is formed on the base side of the valve shaft where the flange portion is formed, and the length of the cylindrical portion is set to a length with which the ball can abut. The valve shaft bearing structure according to any one of claims 1 to 4, wherein the bearing structure is a valve shaft.   The valve shaft bearing structure according to claim 1, wherein a washer member is disposed between the ball and the ceiling portion of the valve guide.   The valve shaft bearing structure according to claim 1, wherein a lower protrusion is formed on a lower surface of the ceiling portion.

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