JP6175715B2 - Stepping motor driven control valve - Google Patents

Description

  The present invention relates to a control valve driven by a stepping motor, and more particularly to a control valve suitable for mounting on a vehicle.

  The vehicle air conditioner has a refrigeration cycle including a compressor, an outdoor heat exchanger, an evaporator, an indoor heat exchanger, and the like, and the function of the outdoor heat exchanger is switched between a heating operation and a cooling operation. During the heating operation, the outdoor heat exchanger functions as an evaporator. At that time, the indoor heat exchanger dissipates heat while the refrigerant circulates through the refrigeration cycle, and the air in the passenger compartment is heated by the heat. On the other hand, the outdoor heat exchanger functions as a condenser during the cooling operation. At that time, the refrigerant condensed in the outdoor heat exchanger evaporates in the evaporator, and the air in the passenger compartment is cooled by the latent heat of evaporation. At that time, dehumidification is also performed.

  Thus, when a plurality of evaporators function depending on the operation state of the refrigeration cycle, it is necessary to adjust the ratio of the refrigerant flow rate flowing through each evaporator. The same applies when a plurality of condensers function. For this reason, a control valve capable of electrically adjusting the valve opening degree may be provided at a specific position in the refrigerant circulation passage. In particular, when precise control of the valve opening is required, a stepping motor driven control valve, which is often found in residential air conditioners, is used. This is because the amount of displacement of the valve body and thus the valve opening can be adjusted accurately by setting the number of steps (number of drive pulses).

  As such a control valve, there is one having an operation conversion mechanism that converts the rotational motion of the rotor into the translational motion of the drive shaft to drive the valve body in the opening / closing direction of the valve portion. However, since it is necessary to limit the driving amount of the valve body to the set range, a stopper mechanism is provided for restricting the rotation of the rotor in one direction and the other direction. For example, a one-turn coiled rotation stopper is engaged with a spiral guide portion extending from the body, the rotation stopper is rotated with the rotor, displaced in the axial direction, and locked at the end of the guide portion. Is stopped (see, for example, Patent Document 1). There is also a type in which a rotary slider is screwed into a guide male screw extending from the body, the rotary slider is rotated with the rotor, displaced in the axial direction, and stopped at the end of the guide male screw to stop the rotation of the rotor. (For example, refer to Patent Document 2).

JP 2012-107709 A JP 2010-38219 A

  However, in the configuration described in Patent Document 1, since the rotation stopper is coiled, play with the guide portion is large, and it is easy to be affected by vibrations transmitted from the vehicle. Easy to do. Further, since the rigidity of the rotation stopper is small, there is a problem that the deflection at the end of the guide portion is large, and the control origin position based on the stop position of the rotor is difficult to determine. In this respect, the rotary slider described in Patent Document 2 is advantageous in terms of rigidity, but because it is configured to rotate with translation, its behavior is not stable, and it is easily affected by vibrations transmitted from the vehicle. For this reason, the problem that it is easy to generate abnormal noise remains.

  One of the objects of the present invention is to stably operate a stopper mechanism for limiting the driving range of a valve body in a control valve driven by a stepping motor.

  In order to solve the above-described problem, a control valve according to an aspect of the present invention is a stepping motor-driven control valve, wherein an introduction port for introducing fluid from the upstream side, a lead-out port for leading fluid to the downstream side, and introduction A body having a fluid passage communicating the port and the outlet port, a valve body for opening and closing a valve portion provided in the fluid passage, and a stepping motor including a rotor for driving the valve body in the opening and closing direction of the valve portion; The shaft is provided coaxially with the rotor and supports the valve body at the tip, and a stopper mechanism for limiting the amount of rotation in one direction and the other direction of the shaft.

  The stopper mechanism includes a worm integrally provided on the shaft, a rack that meshes with the worm, a rack guide that is integrally provided on the body and guides the rack to translate parallel to the axis of the worm, and one end side of the worm The first stopper that is provided integrally with the shaft at the other end of the worm, and is provided integrally with the shaft at the other end of the worm. A rack that has moved in the direction and a second stopper that restricts the rotation of the shaft by locking each other.

  According to this aspect, the stopper mechanism that restricts the rotation range of the shaft is realized by a combination of the worm, the rack, the first stopper, and the second stopper. In particular, by adopting a rack, sufficient structural rigidity can be ensured. Further, since the rack is guided in the translation direction along the rack guide provided integrally with the body, the behavior of the rack can be stably maintained. As a result, the stopper mechanism can function stably.

  According to the present invention, in the stepping motor driven control valve, the stopper mechanism for limiting the driving range of the valve body can be stably functioned.

It is a sectional view showing composition of a control valve concerning an embodiment. It is AA arrow sectional drawing of FIG. It is a perspective view which shows the state partly notched in order to demonstrate the external appearance and internal structure of a control valve. It is a disassembled perspective view showing the components of a rotor and an operating rod. It is a figure which shows the structure of a rotor core in detail. It is a figure which shows the structure of a rack guide in detail. It is a figure which shows the structure of a rack in detail. It is a figure which shows the structure of a stopper in detail. It is a figure which shows the operation | movement of a rack typically. It is sectional drawing showing operation | movement of a control valve.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a cross-sectional view illustrating a configuration of a control valve according to the embodiment. FIG. 2 is a cross-sectional view taken along the line AA of FIG. FIG. 3 is a perspective view showing a state in which the control valve is partially cut away in order to explain the appearance and the internal configuration of the control valve.

  The control valve 1 is applied to, for example, a heat pump type air conditioner mounted on a vehicle. This vehicle air conditioner includes a refrigeration cycle (refrigerant circulation circuit) in which a compressor, an indoor condenser, an outdoor heat exchanger, an evaporator, and an accumulator are connected by piping. Air-conditioning of the passenger compartment is performed by heat exchange performed in a process in which the refrigerant circulates while changing state in the refrigeration cycle. Various control valves for appropriately controlling air conditioning are provided in the refrigerant circulation circuit, and the control valve 1 constitutes one of them. The control valve 1 is configured as a proportional valve whose opening degree is adjusted to a set opening degree, and adjusts the flow rate of the refrigerant flowing from the upstream side to the downstream side.

  As shown in FIG. 1, the control valve 1 is configured as an electric valve driven by a stepping motor, and is configured by assembling a valve body 2 and a motor unit 4. The valve body 2 has a body 5 that houses the valve portion. The motor unit 4 is attached so as to seal the upper end opening of the body 5. The body 5 is configured by assembling a stepped cylindrical second body 8 to the upper half of the prismatic first body 6. The first body 6 is made of an aluminum alloy, and the second body 8 is made of a copper alloy. In the modification, the second body 8 may be made of stainless steel (hereinafter referred to as “SUS”).

  An inlet port 10 for introducing the refrigerant from the upstream side is provided at the upper part of one side surface of the first body 6, and a lead-out port 12 for leading the refrigerant to the downstream side is provided at the lower part of the opposite side surface. A vertical connection passage 14 is formed at the center of the first body 6, an upstream passage 16 thereof communicates with the introduction port 10, and a downstream passage 18 communicates with the outlet port 12. In the upper half portion of the first body 6, a stepped circular hole-shaped mounting hole 20 is formed which gradually increases in diameter upward. The connection passage 14 constitutes a part of the attachment hole 20.

  On the other hand, the second body 8 has a stepped cylindrical shape whose outer diameter and inner diameter gradually decrease toward the lower side, and has an outer shape complementary to the mounting hole 20. The second body 8 is attached so as to be fitted into the attachment hole 20 from above the first body 6. A sealing O-ring 22 is interposed between the first body 6 and the second body 8 at the position of the connection passage 14.

  A valve hole 24 is provided at the lower end of the second body 8, and a valve seat 26 is formed at the upper end opening. A communication hole 28 that communicates the inside and the outside is provided on the surface of the second body 8 facing the introduction port 10. The valve hole 24 communicates with the upstream side passage 16 through the communication hole 28. In addition, a communication passage 30 that vertically passes through the second body 8 is provided outside the communication hole 28 so that the refrigerant in the upstream passage 16 can be introduced also to the motor unit 4 side.

  An operation rod 32 (main shaft) extending coaxially from the rotor 31 of the motor unit 4 is inserted into the second body 8. The operating rod 32 supports a needle-like valve body 34 at one end (lower end). When the valve body 34 is attached to or detached from the valve seat 26 from the upstream side, the valve portion is opened and closed.

  A cylindrical slide bearing 36 is press-fitted in the middle stage in the axial direction of the second body 8, and a cylindrical guide member 38 (functioning as a “cylindrical member”) is press-fitted in the upper stage. In the present embodiment, a resin bearing reinforced with a cylindrical metal mesh as a core material is used as the sliding bearing 36. The sliding bearing 36 is an oil-free bearing (bearing having self-lubricating property) using polytetrafluoroethylene (hereinafter referred to as “PTFE”) as a resin material. The sliding bearing 36 is sized so that the dimensional accuracy of the inner diameter and the coaxiality with the second body 8 are enhanced. With such a device, the low friction and wear resistance of the slide bearing 36 is maintained, and the load bearing performance is enhanced. In the modification, a steel plate material may be used as the core material instead of the metal mesh.

  A female screw 39 (functioning as a “female screw portion”) is formed on the inner peripheral surface of the guide member 38. The guide member 38 is obtained by cutting an internal thread 39 on the inner peripheral surface of a pipe material made of SUS. In this embodiment, the female screw 39 is constituted by a trapezoidal screw having a large thrust and excellent wear resistance. In the modification, the female screw 39 may be a triangular screw. A flange portion 40 protruding radially outward is provided at the center of the guide member 38 in the axial direction, and the lower surface of the flange portion 40 is locked to the step portion of the second body 8, thereby restricting the amount of press-fitting. Has been. More specifically, the guide member 38 is lightly press-fitted into the second body 8 and is fixed so as to be pressed from above by a small-diameter ring screw 42 fastened to the upper end of the second body 8. In the modification, the guide member 38 may be fixed to the second body 8 only by press fitting.

  As shown in FIG. 2, a rack guide 44 (functioning as a “guide member”) is erected on the upper surface of the second body 8. The rack guide 44 has a lower half portion as a large diameter portion 46 and an upper half portion as a small diameter portion 48, and a lower end portion fixed to the upper surface of the second body 8. More specifically, the lower end portion of the rack guide 44 is fitted to the circular boss portion 52 obtained by forming the annular fitting groove 50 on the upper surface of the second body 8, and the upper end of the second body 8 is It is fixed so as to be pressed from above by a large-diameter ring screw 54 fastened to the ring. The circular boss portion 52 functions as a “fitting portion” formed coaxially with the valve hole 24. In the modification, the rack guide 44 may be fixed to the second body 8 by press fitting or caulking.

  In the present embodiment, since the second body 8 is formed by turning with a lathe, the valve hole 24 (valve seat 26), the fitting hole of the step portion into which the slide bearing 36 is press-fitted, and the guide member 38 are press-fitted. The stepped fitting hole and the circular boss 52 are coaxial. For this reason, the coaxiality with respect to the valve hole 24 (valve seat 26) of the slide bearing 36, the guide member 38, and the rack guide 44 is high. The plain bearing 36 functions as a “support portion” that supports the lower end portion of the shaft 60.

  The operating rod 32 is configured by assembling a shaft 60, a worm 62 and a stopper 64. The shaft 60 is obtained by cutting a bar made of SUS, and the lower half is enlarged in a cylindrical shape, and a male screw 66 is formed on the outer peripheral surface thereof. In this embodiment, the male screw 66 is a trapezoidal screw having a large thrust and excellent wear resistance. In the modification, the male screw 66 may be a triangular screw. The male screw 66 is screwed with the female screw 39 of the guide member 38. That is, the lower half portion of the shaft 60 functions as a “male screw portion”. In the present embodiment, DLC (diamond-like carbon) treatment is applied to the male screw 66 and the female screw 39 to enhance the load bearing performance. In addition, in a modification, it may replace with DLC process and may employ | adopt other surface treatment excellent in load bearing performance, abrasion resistance, and sliding resistance reduction. Alternatively, precipitation hardening type stainless steel may be employed.

  A stopper 64 and a worm 62 are extrapolated to the upper half of the shaft 60. The upper half of the shaft 60 has a non-circular cross section, and the stopper 64 and the worm 62 also have insertion holes of the same shape. For this reason, the stopper 64 and the worm 62 are prevented from being displaced relative to each other after being inserted into the shaft 60. The stopper 64 is sandwiched between the lower half portion of the shaft 60 and the worm 62.

  A spring 63 (functioning as an “urging member”), a spring receiver 65, and a valve body 34 are accommodated in the lower half of the shaft 60 from above. A cylindrical press-fitting bush 67 is press-fitted concentrically into the lower end opening of the shaft 60, and supports the valve body 34 from below so as to be slidable. The valve body 34 is made of SUS, and the spring receiver 65 and the press-fit bush 67 are made of a copper alloy.

  The valve body 34 passes through the press-fitting bush 67, but has a flange portion 69 protruding outward in the radial direction at an upper end portion thereof. Since the lower surface of the flange portion 69 is locked to the upper surface of the press-fitting bush 67, the valve body 34 is prevented from falling off. The spring receiver 65 transmits a downward urging force (in the valve closing direction) by the spring 63 to the valve body 34. The upper end of the valve body 34 is a hemispherical curved surface, and is in a point contact state with the bottom surface of the spring receiver 65. With such a configuration, even if the spring receiver 65 is slightly inclined, the movement of the valve body 34 in the axial direction is not affected. Further, the valve body 34 rotates integrally with the press-fit bush 67 and the spring receiver 65 when not in contact with the valve seat 26, but the rotation is restricted when in contact with the valve seat 26. The curved surface shape of the valve body 34 suppresses the occurrence of wear with the spring receiver 65 at such a time.

  As shown in FIG. 3, the rack guide 44 is a guide portion 68 that is recessed in a radially outward direction at one location in the circumferential direction of the small-diameter portion 48 and that extends vertically with a predetermined width. The guide portion 68 extends in parallel with the axis of the worm 62 and accommodates a small piece rack 70. The rack 70 has a prismatic main body 71. The main body 71 has a rectangular cross-sectional shape complementary to the guide portion 68 and meshes with the worm 62 on the inner surface side. The rack 70 translates in the vertical direction while being guided by the guide portion 68 as the worm 62 rotates. A locking portion 72 that locks when the rack 70 is located at the top dead center protrudes from the upper surface of the main body 71, and a latch that is locked when the rack 70 is positioned at the bottom dead center on the lower surface. A portion 74 is projected. Details of the configuration and operation of the rack 70 will be described later.

  As shown in FIG. 1, a communication hole 76 that communicates the inside and the outside is provided in a step portion that is a boundary between the large diameter portion 46 and the small diameter portion 48 of the rack guide 44. Further, a communication groove 77 is formed on the inner peripheral surface of the lower end portion of the rack guide 44 to communicate the inside and the outside. The communication groove 77 communicates with the communication passage 30 so that the refrigerant in the upstream passage 16 can be introduced also to the motor unit 4 side. The large diameter portion 46 is inserted into the lower end portion of the rotor 31 with a small clearance. The clearance is set so as to prevent the rotor 31 from touching.

  On the other hand, the motor unit 4 is configured as a stepping motor including a rotor 31 and a stator coil 33. The motor unit 4 has a bottomed cylindrical can 35, and a rotor 31 is arranged inside the can 35 and a stator coil 33 is arranged outside. The can 35 is a cylindrical member that covers the space in which the valve body 34 and its drive mechanism are disposed and that includes the rotor 31. The can 35 is an inner pressure space in which the refrigerant pressure acts and an outer non-pressure space that does not act. Are defined.

  The can 35 includes a non-magnetic cylindrical main body 80, a disk-shaped end member 82 that closes the upper end opening of the main body 80, and an annular connection member 84 that is connected to the lower end of the main body 80. . The connecting member 84 has a male screw formed at the lower end thereof, and also functions as a ring screw. A female screw that can be screwed with the male screw is formed at the upper end of the first body 6, and the motor unit 4 is attached to the body 5 by screwing and fastening the connecting member 84 to the first body 6. Can be fixed. As illustrated, the connection member 84 is assembled so as to be extrapolated to the upper half of the second body 8. An O-ring 86 for sealing is interposed between the upper end portion of the first body 6 and the connection member 84, and the refrigerant introduced from the introduction port 10 passes between the can 35 and the body 5 to the outside. Leakage is prevented. In the modification, the can 35 (connecting member 84) may be fixed to the first body 6 by press fitting, caulking, welding, or the like.

  The stator coil 33 accommodates the exciting coil 88 and is disposed on the outer periphery of the can 35. The stator coil 33 is fixed with respect to the body 5. The stator coil 33 can be connected to the body 5 by, for example, screwing, welding, brazing, caulking, or the like. Since the stator coil 33 is disposed in the atmosphere that is not affected by the pressure of the refrigerant, it is sufficient that the stator coil 33 be fixed with a strength that can withstand vibration in an environment where the control valve 1 is applied, for example, an automobile mounting environment. The fixing strength as high as the can 35 that needs to be fixed with pressure is not necessary.

  The rotor 31 includes a cylindrical rotor core 90 having the shaft 60 as an axis, and a magnet 92 provided along the outer periphery of the rotor core 90. Inside the rotor core 90, an internal space is formed over almost the entire length. On the inner peripheral surface of the rotor core 90, guide portions 94 extending in parallel to the axis are provided every 45 degrees in the circumferential direction. The guide portion 94 is configured by a ridge (rib) extending parallel to the axis.

  Upper end portions of the plurality of guide portions 94 extend inward in the radial direction and are connected by a cylindrical shaft 96. The cylindrical shaft 96 is coaxially fixed to the upper end portion of the operating rod 32 (main shaft). This fixing is performed by fitting the cylindrical shaft 96 to the upper end portion of the operating rod 32 and fastening the nut 98. A stopper 99 for defining the top dead center of the rack 70 is provided at a predetermined position of the cylindrical shaft 96.

  With the configuration described above, the rotor 31 is supported at two points by the small diameter portion 48 of the rack guide 44 and the sliding bearing 36 on the operating rod 32 serving as the rotation shaft. Further, the clearance between the large diameter portion 46 of the rack guide 44 and the guide portion 94 is set so that the swing of the rotor 31 can be limited. For this reason, even if the control valve 1 is mounted on a vehicle, the rotor 31 is hardly affected by vibration and can rotate stably around the axis. The operating rod 32 is pivotally supported by the rack guide 44 at the position of the worm 62. However, since both the worm 62 and the rack guide 44 are made of a self-lubricating resin material, there is no wear between them. There is no problem.

  The rack 70 translates up and down as the rotor 31 rotates. When the rack 70 rises as the rotor 31 rotates in one direction and reaches a predetermined top dead center, the rack 70 and the stopper 99 engage with each other to restrict the rotation of the shaft 60. Thereby, the downward displacement (valve closing direction) of the shaft 60 is regulated. Further, when the rack 70 descends as the rotor 31 rotates in the other direction (opposite direction) and reaches a predetermined bottom dead center, the rack 70 and the stopper 64 engage with each other to rotate the shaft 60. To regulate. Thereby, the upward displacement (the valve opening direction) of the shaft 60 is restricted. That is, in this embodiment, the stopper 99 functions as a “first stopper”, and the stopper 64 functions as a “second stopper”. The worm 62, the rack 70, the stopper 64, and the stopper 99 function as a “stopper mechanism” for limiting the amount of rotation of the shaft 60 in one direction and the other direction.

Next, the detail of each part which comprises the control valve 1 is demonstrated.
FIG. 4 is an exploded perspective view showing components of the rotor 31 and the operating rod 32.
As shown in the drawing, the shaft 60 has a stepped columnar outline that gradually decreases in diameter from the lower side toward the upper side. A fitting portion 102 having a non-circular cross section (so-called D-cut structure) is provided immediately above the male screw 66 in the shaft 60. A male screw 104 is formed at the upper end of the shaft 60. The spring 63, the spring receiver 65, and the valve body 34 are sequentially inserted from the lower end opening of the shaft 60, and these are held in the shaft 60 by press-fitting the press-fitting bush 67.

  The operating rod 32 is assembled by sequentially inserting a stopper 64 and a worm 62 from above the shaft 60. The stopper 64 and the worm 62 are obtained by injection molding a resin material (glass fiber reinforced resin) such as polyphenylene sulfide (hereinafter referred to as “PPS”) containing glass fiber, and have a complementary shape to the fitting portion 102. Insertion holes are provided. For this reason, the stopper 64 and the worm 62 are positioned simultaneously with the assembly to the shaft 60, and displacement after the assembly is prevented.

  When the control valve 1 is assembled, as shown in FIG. 1, the sliding bearing 36 and the guide member 38 are sequentially assembled to the second body 8 and fixed by the ring screw 42. From this state, the operating rod 32 assembled as described above is screwed into the guide member 38 and assembled coaxially. Thereafter, the rack guide 44 is assembled from above with the rack 70 engaged with the worm 62. At this time, the lower end of the rack guide 44 is fitted to the circular boss portion 52 while being positioned so that the rack 70 is accommodated in the guide portion 68, and fixed to the second body 8 by the ring screw 54. In this state, the rotor core 90 is assembled so as to be externally inserted into the rack guide 44, and the nut 31 is fastened to the male screw 104 protruding from the rotor core 90, thereby fixing the rotor 31 to the operating rod 32. In the modification, the rotor core 90 and the shaft 60 may be fixed by a snap ring or a push nut.

  FIG. 5 is a diagram showing the configuration of the rotor core 90 in detail. (A) is a perspective view, (B) is a figure which shows the state which notched (A) partially. (C) is a plan view, and (D) is a bottom view. (E) is a cross-sectional view taken along the line BB in (C), and (F) is a cross-sectional view taken along the line C-C in (C).

  The rotor core 90 is obtained by injection molding a resin material such as PPS and has a self-lubricating property. The rotor core 90 has a cylindrical main body 106, and guide portions 94 protrude from the inner peripheral surface of the main body 106 every 45 degrees. A flange portion 108 protruding outward in the radial direction is provided at the lower end of the main body 106, and a pair of claw portions 110 protruding outward are formed at the upper end. A magnet 92 (not shown) is sandwiched between the flange portion 108 and the claw portion 110 and supported.

  The guide portion 94 has a tapered lower end portion so that it can be easily inserted into the rack guide 44. The virtual circle passing through the inner peripheral surfaces of the plurality of guide portions 94 is configured to be slightly larger than the large-diameter portion 46 of the rack guide 44, but the clearance between the two prevents the rotor core 90 from swinging. It is set to be small enough. The stopper 99 is provided integrally with one of the plurality of guide portions 94, and has a locking surface 112 (functioning as a “first locked surface”) facing the one rotation direction of the rotor core 90.

  FIG. 6 is a diagram showing the configuration of the rack guide 44 in detail. (A) is a perspective view, (B) is a front view, (C) is a plan view, and (B) is a bottom view. (E) is a DD arrow sectional drawing of (B).

  The rack guide 44 is obtained by injection molding a resin material such as PPS containing glass fiber, and has self-lubricating properties. The rack guide 44 is provided with three communication holes 76 so as to vertically penetrate the stepped portion of the large diameter portion 46 and the small diameter portion 48. Further, a communication groove 77 having a predetermined depth is formed in an annular shape in the inner peripheral portion of the lower end of the large diameter portion 46. A pressure receiving portion 114 made of a small protrusion is provided on the upper end surface of one side wall of the guide portion 68, and a pressure receiving portion 116 made of a small protrusion is integrally provided on the lower end surface of the other side surface of the guide portion 68. The pressure receiving portion 114 supports the rack 70 from the opposite side when the rack 70 locks the rotor core 90 at the top dead center. The pressure receiving portion 116 supports the rack 70 from the opposite side when the rack 70 locks the stopper 64 at the bottom dead center. Details of the locking operation by the rack 70 will be described later.

FIG. 7 is a diagram showing the configuration of the rack 70 in detail. (A) is a perspective view showing the rack 70. FIG. (B) is a view showing a state in which the rack 70 is attached to the rack guide 44.
As shown in FIG. 7A, the rack 70 is obtained by injection molding a resin material such as PPS and has self-lubricating properties. The rack 70 has a plurality of teeth formed on one side of a prismatic main body 71.

  A locking portion 72 protrudes from the half of the upper surface of the main body 71 in the width direction, and a locking portion 74 protrudes from the half of the bottom surface in the width direction. The locking portion 72 faces one direction of rotation of the rotor 31 and has a locking surface 122 (functioning as a “first locking surface”) that contacts the stopper 99 and locks the rotation of the rotor core 90. On the other hand, the locking portion 74 faces the other rotation direction of the rotor 31 and contacts the stopper 64 to lock the rotation of the operating rod 32 (functions as a “second locking surface”). Have The locking surfaces 122 and 124 face opposite directions with respect to the rotation direction of the rotor 31.

  As shown in FIG. 7B, the rack 70 is fitted into the guide portion 68 and guided in translation in the longitudinal direction (direction intersecting with the teeth). Since the width of the rack 70 is substantially equal to the opening width of the guide portion 68, the rack 70 is displaced only in the translational direction with the rotation of the worm 62, and the displacement in the rotational direction is restricted. At the top dead center, as shown in the drawing, the locking portion 72 contacts the pressure receiving portion 114 on the side surface opposite to the locking surface 122. At the bottom dead center, the locking portion 74 contacts the pressure receiving portion 116 on the side surface opposite to the locking surface 124.

FIG. 8 is a diagram showing the configuration of the stopper 64 in detail. (A) is a perspective view, (B) is a front view, (C) is a right side view, (D) is a left side view, (E) is a plan view, and (F) is a bottom view.
The stopper 64 is obtained by injection molding a resin material such as PPS, and has an annular main body 130. As described above, the insertion hole 132 formed in the main body 130 is formed in a non-circular shape that can be fitted into the notch 102 of the shaft 60.

  A locking portion 134 is provided so as to protrude radially outward from the side surface of the main body 130. The locking portion 134 is a portion that locks the rack 70 and each other to stop the rotation of the operating rod 32. A locking surface 136 (functioning as a “second locked surface”) facing the rotation direction is formed in the locking portion 134. On the upper surface of the main body 130, a fitting protrusion 138 is provided for fitting with the worm 62 and positioning each other with high accuracy. Further, a fitting protrusion 140 is provided on the lower surface of the main body 130 to fit the shaft 60 and position each other with high accuracy.

  FIG. 9 is a diagram schematically showing the operation of the rack 70. (A) shows a state when the rack 70 reaches the top dead center, and (B) shows a state when the rack 70 reaches the bottom dead center. Each drawing corresponds to a view seen from the back side (the guide portion 68 side) of the rack guide 44.

  As shown in FIG. 9A, when the rack 70 reaches the top dead center due to the forward rotation of the rotor 31, the locking surface 122 of the locking portion 72 comes into contact with the locking surface 112 of the stopper 99. Lock. As a result, the rotation of the rotor 31 is stopped, and the driving of the valve body 34 in the valve closing direction is also stopped. At this time, since the stopper 99 abuts on the locking portion 72 and the pressure receiving portion 114 receives the locking portion 72 from the side opposite to the stopper 99, the rotational force acting on the locking portion 72 is referred to as the compression force. can do. Thereby, it can prevent that the local force by a shearing force acts on the latching | locking part 72, and the durability can be maintained.

  On the other hand, as shown in FIG. 9B, when the rack 70 reaches the bottom dead center due to the reverse rotation of the rotor 31, the locking surface 124 of the locking portion 74 comes into contact with the locking surface 136 of the locking portion 134. To lock it. As a result, the rotation of the rotor 31 is stopped, and the driving of the valve body 34 in the valve opening direction is also stopped. At this time, since the locking part 134 contacts the locking part 74 and the pressure receiving part 116 receives the locking part 74 from the side opposite to the locking part 134, the rotational force acting on the locking part 74 Can be a compression force. Thereby, it can prevent that the local force by a shearing force acts on the latching | locking part 74, and the durability can be maintained.

  In this embodiment, the screw pitch of the operation converting mechanism by the shaft 60 and the guide member 38 is set to 0.5 mm, whereas the screw pitch of the stopper mechanism by the worm 62 and the rack 70 is 1.2 mm. ing. That is, the screw pitch of the stopper mechanism is larger than the screw pitch of the operation conversion mechanism. As a result, the amount of translation of the rack 70 per rotation of the shaft 60 can be increased while allowing precise valve opening adjustment. As a result, the contact surface between the locking portion 72 and the stopper 99 and the contact surface between the locking portion 74 and the stopper 64 can be increased, and the locking force can be sufficiently secured. Yes.

  The control valve 1 configured as described above functions as a stepping motor actuated control valve whose valve opening can be adjusted by drive control of the motor unit 4. Hereinafter, the overall operation of the control valve 1 will be described. FIG. 10 is a cross-sectional view illustrating the operation of the control valve. FIG. 1 which has already been described shows a closed valve state, and FIG. 10 shows a fully opened state.

  In the flow control of the control valve 1, a control unit (not shown) of the vehicle air conditioner calculates the number of driving steps of the stepping motor according to the set opening and supplies a driving current (driving pulse) to the exciting coil 88. As a result, when the rotor 31 rotates, the shaft 60 also rotates accordingly. At this time, the shaft 60 translates in the vertical direction, that is, in the opening / closing direction of the valve portion, by the screw mechanism between the guide member 38 and the opening degree of the valve portion is adjusted to the set opening degree. That is, this screw mechanism drives the valve body 34 in the opening / closing direction of the valve portion by converting the rotational motion around the axis of the rotor 31 into translational motion (straight motion) in the axial direction of the shaft 60 (actuating rod 32). It functions as an “operation conversion mechanism”.

  Further, when the rack 70 is driven along the guide portion 68, the operating range of the valve element 34 is restricted to the range between the bottom dead center shown in FIG. 1 and the top dead center shown in FIG. That is, when the rotor 31 is rotationally driven in one direction (forward rotation) from the valve closed state shown in FIG. 1, the valve body 34 is opened. That is, the shaft 60 rotating together with the rotor 31 is raised by the screw mechanism, and the press-fit bush 67 is displaced in the valve opening direction so as to lift the valve body 34. At this time, the rack 70 translates in the opposite direction (that is, downward) with respect to the worm 62 rising integrally with the shaft 60. As the rotor 31 rotates in one direction, the opening degree of the valve portion increases, and when the rack 70 reaches the bottom dead center, as shown in FIG. 34 is stopped at the fully open position.

  On the other hand, when the rotor 31 is rotationally driven (reversely rotated) in the other direction (opposite direction), the opening degree of the valve portion is reduced. That is, the shaft 60 that rotates in reverse with the rotor 31 is lowered by the screw mechanism, and the valve body 34 is displaced in the valve closing direction while being supported by the press-fit bush 67. At this time, the urging force of the spring 63 is transmitted to the valve body 34 via the spring receiver 65, so that the valve body 34 is stably displaced integrally with the press-fit bush 67. At this time, the rack 70 translates in the opposite direction (that is, upward) with respect to the worm 62 descending integrally with the shaft 60. As a result, when the rack 70 reaches the top dead center, as shown in FIG. 1, the rotation of the stopper 99 and the rotor 31 is locked, and the valve element 34 is stopped at the valve closing position. In addition, since the engagement state with the press-fitting bush 67 is released at the same time when the valve body 34 is seated on the valve seat 26, an excessive pressing force does not act between the valve body 34 and the valve seat 26.

  As described above, the rotation of the rotor 31 causes the shaft 60 and the rack 70 to be translated in directions opposite to each other with respect to the axial direction, and the rack 70 is displaced so as to be accommodated in the internal space of the rotor 31. For this reason, the translation stroke of the axial direction as the whole internal mechanism of the control valve 1 can be suppressed small, and the control valve 1 can be comprised compactly.

  Since the rotation speed of the rotor 31 corresponds to the number of drive steps as the control command value, a control unit (not shown) can control the control valve 1 to an arbitrary opening degree. In this embodiment, the valve body 34 strokes 0.5 mm per rotation of the rotor 31.

  As described above, according to the present embodiment, the rack 70 is employed as the stopper mechanism that restricts the rotation range of the shaft 60, so that sufficient structural rigidity can be ensured. In addition, since the rack 70 is guided in the translation direction along the rack guide 44 provided integrally with the body 5 (second body 8), the behavior of the rack 70 can be stably maintained. As a result, the stopper mechanism can function stably. Further, since the worm 62, the rack 70, and the rack guide 44 are made of a resin material, it is possible to reduce the operation noise when the worm 62 operates in the rotation direction and the translation direction and the collision noise when the stopper mechanism functions. it can. Further, since these components are made of a resin material, there is an advantage that there is no resonance point that increases vibration.

  Further, the large-diameter portion 46 of the stepped cylindrical rack guide 44 is fitted to the circular boss portion 52 in which the coaxiality with the valve hole 24 is secured in the body 5 (second body 8). Thereby, the coaxiality between the rack guide 44 and the valve hole 24 can be obtained with high accuracy. On the other hand, the body 5 is further provided with a slide bearing 36 that is secured to the coaxiality with the valve hole 24. The small diameter portion 48 of the rack guide 44 is ensured to be coaxial with the large diameter portion 46. For this reason, the coaxiality of the sliding bearing 36 serving as the bearing on one end side of the operating rod 32 and the small diameter portion 48 serving as the bearing on the other end side can be obtained with high accuracy. Further, since the small diameter portion 48 extends into the internal space of the rotor 31, a sufficient distance between the small diameter portion 48 and the sliding bearing 36, that is, a bearing interval can be secured. That is, the operating rod 32 serving as the rotation shaft of the rotor 31 can be supported not in a cantilever state but in a both-end support state, and the coaxiality of both bearings can be ensured. For this reason, even if it is mounted on a vehicle and receives vibrations, the swing of the rotor 31 can be prevented or suppressed, and the rotation can be stably maintained. As a result, the earthquake resistance as the control valve 1 can be enhanced.

  The preferred embodiments of the present invention have been described above. However, the present invention is not limited to the specific embodiments, and various modifications can be made within the scope of the technical idea of the present invention. Nor.

  In the above-described embodiment, an example in which the control valve is configured as a two-way valve having one outlet port with respect to one inlet port has been described. In a modification, it can also be configured as a three-way valve having two outlet ports for one introduction port or a four-way valve having two outlet ports for two introduction ports.

  In the above-described embodiment, the structure in which the valve portion is opened / closed by attaching / detaching to / from the valve seat as the control valve is shown. Moreover, in the said embodiment, the structure which opens and closes a valve part by translating a valve body as a control valve was shown, However, It is good also as a butterfly valve which rotates a valve body around an axis line and opens and closes a valve part. In this case, an operation conversion mechanism that converts the rotation operation of the rotor into the translation operation of the shaft is omitted.

  In the above embodiment, the stopper mechanism has been described with respect to the configuration in which the stopper on the rotor side is locked in the rotational direction (configuration in which the locking surfaces of the stopper and the rack face in the rotational direction). It is good also as a structure stopped (structure in which each locking surface of a stopper and a rack faces an axial direction).

  In the above embodiment, the screw pitch of the operation conversion mechanism and the screw pitch of the stopper mechanism are made different from each other.

  In the above-described embodiment, the configuration in which the sliding bearing 36 as a separate member is press-fitted into the second body 8 as the support portion is shown, but a support hole as a support portion may be integrally formed with the second body 8. In that case, a solid lubricating coating such as DLC may be applied to the support hole.

  In the above embodiment, the body 5 is divided into the first body 6 and the second body 8, but may be configured integrally. In that case, it is preferable to constitute the body 5 in a cylindrical shape so that the body 5 can be turned by a lathe.

  In the above embodiment, an example in which the control valve is applied to an air conditioning apparatus for an electric vehicle has been described. However, the control valve can also be applied to an air conditioning apparatus for an automobile equipped with an internal combustion engine or a hybrid automobile equipped with an internal combustion engine and an electric motor. Needless to say. Furthermore, the present invention can be applied not only to a vehicle but also to a device equipped with an electrically driven valve, and can be applied to a device in which a fluid other than a refrigerant such as water or oil flows.

  In addition, this invention is not limited to the said embodiment and modification, A component can be deform | transformed and embodied in the range which does not deviate from a summary. Various inventions may be formed by appropriately combining a plurality of constituent elements disclosed in the above embodiments and modifications. Moreover, you may delete some components from all the components shown by the said embodiment and modification.

  DESCRIPTION OF SYMBOLS 1 Control valve, 2 Valve body, 4 Motor unit, 5 Body, 6 1st body, 8 2nd body, 10 Introducing port, 12 Deriving port, 20 Mounting hole, 24 Valve hole, 26 Valve seat, 31 Rotor, 32 Actuation Rod, 33 Stator coil, 34 Valve body, 35 Can, 36 Slide bearing, 38 Guide member, 39 Female thread, 44 Rack guide, 52 Circular boss part, 60 Shaft, 62 Worm, 64 Stopper, 66 Male thread, 67 Press-fit bush, 68 Guide part, 70 rack, 72, 74 locking part, 99 stopper, 112 locking surface, 114, 116 pressure receiving part, 122, 124 locking surface, 134 locking part, 136 locking surface, 138, 140 fitting protrusion .

Claims (8)

In stepping motor drive type control valve,
A body having an introduction port for introducing a fluid from the upstream side, a derivation port for deriving the fluid to the downstream side, and a fluid passage communicating the introduction port and the derivation port;
A valve body for opening and closing a valve portion provided in the fluid passage;
A stepping motor including a rotor for driving the valve body in the opening and closing direction of the valve portion;
A shaft that is coaxially provided on the rotor and supports the valve body at a tip portion;
A stopper mechanism for limiting the amount of rotation in one direction and the other direction of the shaft;
With
The stopper mechanism is
A worm provided integrally with the shaft;
A rack meshing with the worm;
A rack guide that is provided integrally with the body and guides the rack to translate parallel to the axis of the worm;
A first stopper that is provided integrally with the shaft on one end side of the worm and restricts the rotation of the shaft by locking the rack that has moved in one direction;
A second stopper which is provided integrally with the shaft on the other end side of the worm and regulates the rotation of the shaft by locking the rack and the rack which have moved in the other direction;
A control valve comprising: The rack guide has a guide portion extending in parallel with the axis of the worm,
The rack is configured to be smaller in the axial direction than the worm, is restricted in rotation by fitting with the guide portion, and is guided in the translational direction by the guide portion as the worm rotates. The control valve according to claim 1. While the shaft is made of a metal material, the worm, the rack, and the rack guide are made of a resin material,
The control valve according to claim 1, wherein the worm is fixed so as to be extrapolated to the shaft. The first stopper has a first locked surface facing in one rotation direction,
The second stopper has a second locked surface facing the other rotation direction,
The rack has, on one end side, a first locking surface that can lock the first locked surface in the one rotation direction, and locks the second locked surface in the other rotation direction. The control valve according to claim 1, further comprising a second locking surface that can be provided on the other end side. The rotor has a hollow shape,
The shaft is provided so as to penetrate the inner space of the rotor;
The control valve according to any one of claims 1 to 4, wherein the rack guide is extended in an internal space of the rotor so that the rack is displaced in the internal space. . An operation conversion mechanism for driving the valve body in the opening / closing direction of the valve portion by converting rotational movement around the axis of the rotor into translational movement in the axial direction of the shaft;
The valve body opens and closes a valve portion in contact with and away from a valve hole provided in the fluid passage,
The operation conversion mechanism includes a male screw part integrally provided on the shaft, and a female screw part integrally provided on the body and meshing with the male screw part,
The first stopper regulates the translation of the shaft by locking the rack that has moved in one direction with each other,
The control valve according to claim 1, wherein the second stopper restricts the translation of the shaft by locking the rack that has moved in the other direction with each other.   The control valve according to claim 6, wherein a pitch of the worm is set larger than a pitch of the male screw portion.   The control valve according to claim 6 or 7, wherein the shaft and the rack are translated in directions opposite to each other with respect to an axial direction by rotation of the rotor.

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