JP2016037995A - Electric driving valve - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve wear resistance of a component subjected to repetitive collision and impact, such as a stopper, as much as possible, so that malfunction due to abrasion powder is less likely to occur, thereby enhancing durability and reliability.SOLUTION: As a material for a specific component, such as stoppers 46 and 47, that is directly exposed to a coolant and subjected to repetitive collision and impact, a material is used which is obtainable by using a resin having high hardness and chemical resistance (specifically, any one of PPS resin, PEEK resin, and PTFE resin) as a base material, and mixing, into the base material, a reinforcement material having lower hardness than the base material and having solid lubricating properties (specifically, carbon-based materials, such as carbon, graphite, and carbon fiber).SELECTED DRAWING: Figure 2

Description

  The present invention relates to an electric drive valve such as an electric valve or an electromagnetic valve, and more particularly to an electric drive valve suitable for use in a refrigeration cycle in which a refrigerant circulates.

  As an electric valve that is one of electrically driven valves used in a refrigeration cycle in which a refrigerant circulates, for example, as described in Patent Documents 1 and 2, the valve element is brought into contact with the valve seat using the rotation of the rotor. Some include a screw feed mechanism for separating them and a synthetic resin stopper mechanism (movable stopper, fixed stopper) that defines a movable range of the valve body.

  In this first type motor-operated valve, a fixed screw portion (male screw portion) formed on the outer periphery of a guide bush fixed to the valve body, and a moving screw portion formed on the inner periphery of the valve shaft holder integrated with the rotor ( When the rotor is rotated in one direction by this screw feed mechanism, the rotor and the valve shaft holder integrated with the rotor are lowered while rotating, for example, and the valve shaft is rotated accordingly. The valve body provided at the lower end of the valve body is also lowered, and the flow rate of the refrigerant is adjusted by changing the lift amount (= valve opening degree) of the valve body with respect to the valve seat.

  In the motor-operated valve, a compression coil spring that constantly urges the valve shaft downward (in the valve closing direction) is mounted between the valve shaft holder and the valve shaft. This compression coil spring is provided for increasing the contact surface pressure of the valve body with respect to the valve seat (valve port) to improve the shut-off property (sealing performance) between them and for buffering.

  In the electric valve of the first type, when the rotor and the valve shaft holder are continuously rotated and lowered, the valve body is pressed against the valve seat and the valve opening is closed. At this time, the movable stopper provided on the valve shaft holder does not yet collide with the fixed stopper provided on the valve body side (guide bush), and the valve shaft holder is further rotated and lowered while the valve body is closed. I'm damned. At this time, since the valve shaft holder is lowered with respect to the valve shaft, the downward force (momentum) of the valve shaft holder is absorbed (damped) by the compression of the coil spring. Thereafter, when the valve shaft holder is further lowered, the movable stopper collides with the fixed stopper, and even if energization (pulse supply) to the stator is continued, the lowering of the valve shaft holder is forcibly stopped. The position is the lowest position.

  Thus, even after the valve body is pressed against the valve seat and the valve opening is closed, the valve shaft holder is lowered and the coil spring is compressed.

  On the other hand, conventionally, in electrically driven valves used in refrigerators and air conditioners, in the fully closed state, if no refrigerant flows, oil (lubricating oil) mixed in the refrigerant slides in the compressor. It may not be supplied to the part or the like, and there is a risk of causing problems such as seizure of the compressor. For this reason, in order to prevent this, as seen in Patent Document 3, for example, a cut groove or the like is formed in the valve seat, and even when the valve body is seated on the valve seat (valve closed state), a small amount is required. There is an electric valve of the second type in which a refrigerant flows.

  In recent years, there has been a demand for an electric valve capable of high-precision control even at a very small flow rate in order to improve energy savings. A third type motor-operated valve that is not seated on the seat, that is, not closed may be used. In the third type motor-operated valve, the movable stopper collides with the fixed stopper in a slightly opened state of fine opening before the valve element is seated, so that the valve is not fully closed, and is slightly opened. The refrigerant is caused to flow from the gap between the valve body and the valve seat.

  In this third type motor-operated valve as well, a compression coil spring that constantly urges the valve shaft downward (in the valve closing direction) is mounted between the valve shaft holder and the valve shaft. Unlike the coil spring in the first type motor-operated valve, the coil spring is merely urged lightly so that the valve shaft holder and the valve shaft are not separated from each other.

Japanese Patent No. 3701385 JP2013-122281A Japanese Patent Laid-Open No. 11-51514

  The conventional electrically driven valve, particularly the third type motor-operated valve that does not close, has the following problems.

  That is, in the conventional motor valve of the first type, when the movable stopper collides with the fixed stopper and the rotation lowering of the valve shaft holder is forcibly stopped, the coil spring is compressed, thereby obtaining a damper effect. However, in the third type motor-operated valve, the valve body is not seated on the valve seat, so the coil spring that is compressed between the valve shaft holder and the valve shaft is not further compressed, and the above-mentioned Such a damper effect cannot be obtained, the collision energy between the movable stopper and the fixed stopper becomes larger than the former, and both the resin stoppers may be worn.

  If the stopper is worn, the collision position of the movable stopper and the fixed stopper will be shifted, the base point will shift, etc., and the flow rate adjustment at a small opening will not be performed properly. Not only valves, but also compressors and other devices distributed in the refrigerant circulation circuit may cause malfunctions and malfunctions such as sliding parts becoming worn or clogged and component parts locked. There is a problem that it tends to occur.

  The present invention has been made in view of the above circumstances, and the object of the present invention is to improve the wear resistance of parts such as stoppers where collision and impact are repeated as much as possible, resulting from wear powder. It is an object of the present invention to provide an electrically driven valve that is less likely to cause malfunction and has improved durability and reliability.

  In order to achieve the above-mentioned object, the inventors of the present application have conducted extensive research, and as a wear mechanism, wear powder generated by initial wear adheres to the stopper collision surface, and the high hardness glass contained in the wear powder. It was found that the powder acts like an abrasive and accelerates the wear at the time of stopper collision.

  Therefore, the inventors of the present application paid attention to the mineral hardness of the reinforcing material mixed in the base resin such as a stopper. Table 1 shows the mineral hardness of the related substances.

  The hardness of the PPS resin is 1.5 to 2.5 equivalent to the component sulfur, and the glass powder has a higher hardness of 4.5 to 6.5. It can be seen that it occurs.

  Further, it has been found that the wear resistance is improved by using a resin material reinforced with a substance having a lower hardness than that of the base resin material as the stopper material.

  The present invention has been made on the basis of the above-mentioned knowledge, considerations based on it, trial manufacture / experiment, etc., and the electrically driven valve according to the present invention is basically directly exposed to the refrigerant and is not subject to collision / impact. As a material for a specific resin part to be repeated, a material obtained by mixing a base material with a resin having high hardness and excellent chemical resistance, and mixing a reinforcing material having a lower hardness and solid lubricity into the base material. It is characterized by use.

  As the base material of the specific part, preferably, any of PPS (polyphenylene sulfide) resin, PEEK (polyether ether ketone) resin, and PTFE (polytetrafluoroethylene) resin is used.

  These resins are characterized by high hardness, excellent chemical resistance, and a wide temperature range that can be handled. The refrigerant temperature in the refrigeration cycle reaches about −40 ° C. in the low temperature region and about 120 ° C. in the high temperature region at the motor operated valve (expansion valve), but the resin is stable in a wide temperature range exceeding this temperature range. ing.

  As the reinforcing material for the specific component, a carbon-based material such as carbon, graphite, or carbon fiber is preferably used.

  In addition to having a lower hardness than the base material, the carbon-based reinforcing material itself has solid lubricity, so that the reinforcing material becomes a fine powder during repeated collisions and impacts. Even if ejected, the fine powder is very light and may remain attached, so that it remains attached in the vicinity, and even if it flows together with the refrigerant, it is rich in lubricity. There is an advantage that it is less likely to be a hindrance to dynamic operation.

  In a specific preferred embodiment, the electrically driven valve according to the present invention has a screw feed mechanism for moving the valve element to and away from the valve seat using the rotation of the rotor, and a movable provided on the rotor side. A stopper and a fixed stopper provided on the valve seat side, and the movable stopper is made to collide with the fixed stopper in a slightly opened state before the valve body is seated on the valve seat. In the motor-operated valve that is not allowed to be in a closed state, as a material of the movable stopper and the fixed stopper, any one of PPS resin, PEEK resin, and PTFE resin is used as a base material, and the base material is made of carbon, graphite, A material obtained by mixing a carbon-based material such as carbon fiber as a reinforcing material is used.

  In the electrically driven valve according to the present invention, as a material for a specific part made of resin that is directly exposed to a refrigerant such as a stopper and repeatedly undergoes collision and impact, a resin having high hardness and excellent chemical resistance, specifically, One of PPS resin, PEEK resin, and PTFE resin is used as a base material, and the base material is made of a reinforcing material having lower hardness and solid lubricity, specifically carbon, graphite, carbon fiber, etc. Since a material mixed with a carbon-based substance is used, the wear powder (glass powder) works like an abrasive and accelerates the wear at an accelerated rate, like the conventional glass fiber reinforced grade PPS. As a result, the wear resistance is remarkably improved.

  In this case, even if the carbon-based reinforcing material is produced as a fine powder, most of the carbon-based reinforcing material remains attached in the vicinity, and even if it flows together with the refrigerant, it has high lubricity. There is no obstacle to equipment such as compressors distributed in the circulation circuit.

  As described above, according to the present invention, it is possible to dramatically improve the wear resistance of parts such as stoppers, which are repeatedly subjected to collision and impact, and to reliably prevent malfunctions caused by wear powder. There is an excellent effect that durability and reliability can be enhanced.

The partial notch longitudinal cross-sectional view which shows one Example of the electrically driven valve (electric valve) which concerns on this invention. The stopper mechanism of the motor operated valve shown in FIG. 1 is shown, (A) is a partially cutaway plan view, and (B) is a cross-sectional view taken along the line u-u in (A).

Embodiments of the present invention will be described below with reference to the drawings.
One embodiment of a motor-operated valve as an electrically driven valve according to the present invention is shown in FIG.

  The motor-operated valve 10 in the illustrated example includes a screw feed mechanism 18 for moving the valve element 25 to and away from the valve seat 23 by utilizing the rotation of the rotor 30, and a movable stopper 47 provided on the rotor 30 side and the valve seat 23 side. A stopper mechanism 45 comprising a fixed stopper 46 provided on the valve body 20 side is provided, and the movable stopper 47 is fixed in a slightly opened state before the valve body 25 is seated on the valve seat 23. The valve 46 is prevented from colliding with the stopper 46 to be in a closed state.

  Specifically, the motor-operated valve 10 includes a valve shaft 24 integrally provided with a valve body 25 having an inverted frustoconical portion at a lower end, a valve body 20 having a valve chamber 21 and a valve seat 23 with a valve port 22. The can 40 having its lower end sealed and joined to the valve body 20, the rotor 30 disposed with a predetermined gap α on the inner periphery of the can 40, and the can 40 for rotationally driving the rotor 30 A stepping motor 60 having an externally fitted stator 50, and a screw feed mechanism 18 that contacts and separates the valve body 25 from the valve port 22 by utilizing the rotation of the rotor 30, and the lift amount of the valve body 25 (= open) The flow rate of the refrigerant is adjusted by changing the degree).

  A first inlet / outlet 11 made of a conduit joint is provided at one side of the valve chamber 21 of the valve body 20, and a valve seat 23 with a valve port (orifice) 22 is formed at the lower part, and the valve port 22. The 2nd entrance / exit 12 which consists of a conduit joint is provided. The valve shaft 24, the valve body 25, the valve seat 23 with the valve port 22, and the second inlet / outlet 12 are substantially disposed on the rotation axis O of the rotor 30.

  The stator 50 has two-phase stator coils 50A and 50B. Each stator coil 50A and 50B includes a pair of upper and lower yokes 51, a bobbin 52 fitted around the yoke 51, and a coil 53 wound around the bobbin. The stator coils 50 </ b> A and 50 </ b> B are stacked one above the other, and a resin 56 is coated and filled by molding at the outer periphery and the inner space thereof. The stator coils 50A and 50B are energized and energized via the energizing cable 58, the connector portion 57, and the like. An anti-rotation member 42 for preventing relative rotation and relative movement between the stator 50, the can 40 and the valve body 20 is attached and fixed to the lower surface portion of the stator 50 (the locking portion and the like are not shown). .

  In the fitting hole 27 provided in the valve body 20, the lower half portion 26a of the lower large diameter portion 26a of the cylindrical guide bush 26 is press-fitted and fixed. On the outer periphery of the lower half portion of the upper small-diameter portion 26b in the guide bush 26, a fixed male screw portion 28 constituting one side of the screw feed mechanism 18 is formed. A large-diameter portion 24a of the valve shaft 24 is slidably fitted into the guide bush 26 with its lower portion (valve element 25) protruding downward.

  A support ring 36 is integrally coupled to the upper portion of the rotor 30, and an upper projecting portion of a cylindrical valve shaft holder 32 with a ceiling portion 32 a whose bottom surface is opened is caulked and fixed to the support ring 36. .

  On the inner periphery of the lower portion of the valve shaft holder 32, a movable female screw portion 38 constituting the other side of the screw feed mechanism 18 that is screwed into a fixed male screw portion 28 formed on the guide bush 26 is formed.

  The upper small diameter portion 26b of the guide bush 26 is inserted in the upper portion of the valve shaft holder 32, and the upper small diameter portion 24b of the valve shaft 24 is formed at the center of the ceiling portion 32a of the valve shaft holder 32 (through hole formed therein). Has been passed. A push nut 33 is press-fitted and fixed to the upper end portion of the upper small diameter portion 24 b of the valve shaft 24.

  The valve shaft 24 is extrapolated to the upper small-diameter portion 24b of the valve shaft 24, and is contracted between the ceiling portion 32a of the valve shaft holder 32 and the upper terrace surface of the lower large-diameter portion 24a of the valve shaft 24. The mounted compression coil spring 34 is always urged downward (in the valve closing direction).

  Therefore, the valve shaft 24 is raised and lowered along with the valve shaft holder 32 in a state where the push nut 33 press-fitted and fixed to the upper end portion is pressed against the ceiling portion 32 a of the valve shaft holder 32. The outer peripheral side of the push nut 33 on the ceiling portion 32a of the valve shaft holder 32 is re-engaged when the fixed male screw portion 28 and the movable female screw portion 38 constituting the screw feed mechanism 18 are disengaged. A return coil spring 35 is arranged to facilitate the operation.

  On the other hand, the valve shaft holder 32 and the guide bush 26 are provided with a stopper mechanism 45 for preventing further rotation and lowering when the rotor 30 is lowered while rotating to a predetermined position by the screw feed mechanism 18. Yes. More specifically, a thick short cylindrical movable base 44 made of reinforced resin, which will be described later, is provided on the outer periphery of the lower portion of the valve shaft holder 32 so as to project downward. So that it is molded and fixed. Further, on the outer periphery of the upper portion of the lower large diameter portion 26a of the guide bush 26, a convex fixed stopper 46 that protrudes upward is provided so that the movable stopper 47 collides and stops. The base 43 is molded and fixed.

  As shown in FIG. 2, the movable stopper 47 and the fixed stopper 46 have a relatively elongated side view in order to ensure sufficient strength and durability and for convenience of molding. Further, in plan view, the front and rear end surfaces are in surface contact and both side surfaces rotate about the rotation axis O of the rotor 30 in order to increase the contact area between the stoppers and reduce the collision load per unit area. It has a fan shape positioned on a concentric circle with a rotation radius r so as to follow a trajectory drawn by the movable stopper 47 moved up and down (spiral motion), and its width (thickness in the radial direction) is constant.

  In addition, the escape inclined surface 47t for avoiding contact with the rear part of the movable stopper 47 and the front part of the fixed stopper 46 when passing through the other stopper as viewed in the rotational direction when the movable stopper 47 is lowered. 46t are formed.

  In the motor-operated valve 10 configured as described above, the rotor 30 is made to the guide bush 26 fixed to the valve body 20 by energizing (pulse supply) the stator coils 50A and 50B in the first mode. The valve shaft holder 32 is rotated clockwise, for example, and the valve shaft holder 32 is rotated and lowered, for example, by screw feed between the fixed male screw portion 28 of the guide bush 26 and the movable female screw portion 38 of the valve shaft holder 32. Accordingly, the valve shaft 24 and the valve body 25 are lowered, the lift amount (opening) of the valve body 25 from the valve seat 23 is gradually decreased, and the passing flow rate is decreased.

  When the valve shaft holder 32 is lowered while rotating together with the rotor 30, the movable stopper 47 eventually collides with the fixed stopper 46. Thereafter, even if the pulse supply to each of the stator coils 50 </ b> A and 50 </ b> B is continued, The rotation descent is forcibly stopped. The valve opening when the movable stopper 47 collides with the fixed stopper 46 is the minimum opening of the motor-operated valve 10 of the present embodiment. As described above, this motor-operated valve does not take the fully closed state, and this minimum The refrigerant is caused to flow through the gap between the valve body 25 and the valve seat 23 that are slightly opened at the opening.

  On the other hand, when each stator coil 50A, 50B is energized (pulsed) in the second mode, the rotor 30 and the valve shaft holder 32 rotate in the opposite direction (counterclockwise) with respect to the guide bush 26 fixed to the valve body 20. The movable stopper 47 is moved away from the fixed stopper 46 by the screw feed between the fixed male screw portion 28 of the guide bush 26 and the movable female screw portion 38 of the valve shaft holder 32, and this time, the valve shaft holder 32 rises while rotating. Along with this, the valve shaft 24 and the valve body 25 rise, the lift amount (opening) of the valve body 25 from the valve seat 23 gradually increases, and the passing flow rate increases.

  In this case, the lift amount (= valve opening degree) of the valve body 25 can be arbitrarily finely adjusted by the rotation amount of the rotor 30, and the rotation amount of the rotor 30 is controlled by the number of supply pulses, so that the refrigerant flow rate is increased. The accuracy can be controlled.

  In this embodiment, the material of the movable base 44 with the convex movable stopper 47 projecting downward and the fixed base 43 with the convex fixed stopper 46 projecting upward is high hardness and resistant. A resin with excellent chemical properties (specifically, PPS resin) is used as a base material, and a reinforcing material (specifically, carbon, graphite, carbon fiber) having a lower hardness and solid lubricity is mixed in the base material. This material is used.

  For this reason, like conventional glass fiber reinforced grade PPS, it is possible to surely avoid the problem that wear powder (glass powder) works like an abrasive and accelerates wear, As a result, the wear resistance is remarkably improved.

  In addition to the PPS resin, PEEK resin, PTFE resin, or the like may be used as the base material.

  When a carbon-based material is used as a reinforcing material, even if the carbon-based reinforcing material is produced as a fine powder, most of the carbon-based reinforcing material remains attached in the vicinity, and even if it flows together with the refrigerant, it is rich in lubricity. The electric valve 10 and the equipment such as a compressor distributed in the refrigerant circulation circuit are not damaged.

  Thus, in the motor-operated valve 10 according to the embodiment of the present invention, the material of the movable stopper 47 and the fixed stopper 46 in which the collision / impact is repeated can be improved. There is an excellent effect that the durability and the reliability can be improved.

  In the above-described embodiment, the example in which the present invention is applied to the stoppers 46 and 47 of the motor-operated valve 10 has been described. However, the present invention is not limited to this, and may be applied to other electrically driven valves such as electromagnetic valves. The applied parts are not limited to the stoppers, and similar effects can be obtained even when the present invention is applied to parts that are frequently subjected to collision and impact.

DESCRIPTION OF SYMBOLS 10 Motorized valve 18 Screw feed mechanism 20 Valve main body 21 Valve chamber 22 Valve port 23 Valve seat 24 Valve shaft 25 Valve body 26 Guide bush 28 Fixed male screw portion 30 Rotor 32 Valve shaft holder 38 Movable female screw portion 40 Can 45 Stopper mechanism 46 Fixed stopper 47 Movable stopper 50 Stator

Claims (5)

  It has a resin specific part that is directly exposed to the refrigerant and repeatedly collides or receives an impact. As a material of the specific part, a resin having high hardness and excellent chemical resistance is used as a base material. An electrically driven valve characterized in that a material obtained by mixing a base material with a reinforcing material having lower hardness and solid lubricity is used.   2. The electrically driven valve according to claim 1, wherein any one of PPS resin, PEEK resin, and PTFE resin is used as a base material of the specific part.   The electrically driven valve according to claim 1, wherein a carbon-based material such as carbon, graphite, or carbon fiber is used as the reinforcing material for the specific part.   The electrically driven valve according to claim 1, wherein the specific component is a component including a stopper that determines a movable range of the valve body. A screw feed mechanism for moving the valve body to and away from the valve seat using rotation of the rotor; a movable stopper provided on the rotor side; and a fixed stopper provided on the valve seat side; Is an electrically driven valve that prevents the movable stopper from colliding with the fixed stopper in a slightly opened minute opening state before being seated on the valve seat.
As a material for the movable stopper and the fixed stopper, a material obtained by mixing one of PPS resin, PEEK resin, and PTFE resin as a base material and mixing a carbon-based reinforcing material such as carbon, graphite, and carbon fiber into the base material. An electrically driven valve characterized by being used.

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