Electric valve and planetary gear type speed reduction mechanism

Abstract

To provide a novel technology capable of improving a degree of freedom for design in an electric valve and a planetary gear type speed reduction mechanism.SOLUTION: An electric valve comprises: an electric motor; a planetary gear type speed reduction mechanism (speed reduction mechanism 60) that comprises a planetary gear 65 comprising a first tooth T1 to which an input rotation of the electric motor is input, and a second tooth T2 corresponding to the first tooth T1 and having a module different from the module of the first tooth T1, and an output gear 66 that meshes with the second tooth T2 and outputs an output rotation that the input rotation is reduced; and a valve body part that controls an opening degree of the valve by the output rotation.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present disclosure relates to a motor-operated valve and a planetary gear type reduction mechanism. [Background technology]

[0002] Conventionally, as disclosed in Patent Document 1, there is known a type of motor-operated valve that reduces the input rotation of a rotor with a planetary gear type reduction mechanism and transmits the reduced output rotation to a screw mechanism that controls the opening and closing of the valve, as an electric valve that opens and closes the valve via an electric motor. Specifically, Patent Document 1 discloses a paradox planetary gear type differential gear mechanism. In the differential gear mechanism, the fixed gear can rotate at a relatively high reduction ratio depending on the difference in the number of teeth between the fixed gear and the output gear.

[0003] As another example of a planetary gear reduction mechanism, Patent Document 2 discloses a 3K type planetary gear device, which is not an electric valve, but in which all three basic shafts, consisting of an input shaft, an output shaft, and a fixed shaft, have the same rotation axis as the central axis of the device. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 4936941 [Patent Document 2] Patent No. 6782494 Summary of the Invention [Problem to be solved by the invention]

[0005] Here, in one planetary gear, the tooth of the part that meshes with the fixed gear is referred to as the “first tooth,” and the tooth of the part that meshes with the output gear at a position different from the first tooth is referred to as the “second tooth.” In the cases of Patent Documents 1 and 2, in one planetary gear, the module of the first tooth and the module of the second tooth are the same.

[0006] For this reason, the design of not only the planetary gears but also the designs of other gear elements such as the sun gear, fixed gear, and output gear that mesh with the planetary gears are limited to the condition that the modules of the first and second teeth of the planetary gears must be the same. As a result, there is a problem that the degree of freedom in designing the planetary gear type reduction mechanism and the degree of freedom in designing the motor-operated valve using the planetary gear type reduction mechanism are generally reduced.

[0007] In view of the above, the present disclosure provides a novel technology that can improve the design freedom in motor-operated valves and planetary gear type reduction mechanisms. [Means for solving the problem]

[0008] The electric valve of the first aspect comprises: an electric motor; a planetary gear type reduction mechanism having a planetary gear with first teeth to which an input rotation of the electric motor is input and second teeth corresponding to the first teeth and having a module different from the module of the first teeth; and an output gear that meshes with the second teeth and outputs an output rotation that is reduced in speed from the input rotation; and a valve body that controls the opening degree of the valve by the output rotation.

[0009] In the motor-operated valve according to the first aspect, the planetary gear reduction mechanism can be designed without being restricted by the condition that the module of the first tooth and the module of the second tooth be the same, thereby improving the design freedom of the motor-operated valve.

[0010] In a second aspect, in the electric valve of the first aspect, the planetary gear type reduction mechanism includes a fixed gear provided in the input region and having a number of teeth different from the number of teeth of the output gear, and a sun gear arranged concentrically with the fixed gear, to which the input rotation is input and which meshes with the first tooth of the planetary gear.

[0011] In the second aspect, it is possible to realize a paradox planetary gear type reduction mechanism including a fixed gear and a sun gear, among other planetary gear type reduction mechanisms.

[0012] In a third aspect, in the motor-operated valve according to the second aspect, the fixed gear has a root circle diameter of 15 mm or less.

[0013] In the third aspect, the degree of freedom in designing a small motor-operated valve in which the tooth root diameter of the fixed gear is 15 mm or less can be particularly improved.

[0014] A fourth aspect is an electric valve according to any one of the first to third aspects, comprising: a valve body having a valve chamber formed therein; a valve seat having an opening formed in a part of a wall surface of the valve chamber; a valve disc arranged to be able to open and close the opening of the valve seat; a valve rod for moving the valve disc toward and away from the valve seat; a cylindrical can attached to the valve body and forming a space between the valve body and the valve body; an excitation device for the electric motor attached to the outer periphery of the can; a permanent magnet type rotor assembly supported rotatably inside the can and rotated by the excitation device; and a screw mechanism for converting the output rotation from the planetary gear reduction mechanism into a movement of the valve disc toward and away from the valve seat and transmitting the rotation to the valve rod, and the rotor assembly and the planetary gear reduction mechanism are disposed in the space between the valve body and the can.

[0015] In the fourth aspect, the degree of freedom in designing a motor-operated valve can be particularly improved in which a rotor assembly and a planetary gear type reduction mechanism are disposed in the space between the valve body and the can.

[0016] A fifth aspect is an electric valve according to any one of the first to fourth aspects, wherein the output gear is a bottomed tubular member having a bottom and a wall rising from the periphery of the bottom, and a storage space capable of accumulating a fluid is formed inside the tubular member.

[0017] Here, for example, by configuring the second teeth of the planetary gear with the same number of teeth as the first teeth, and making the diameter of the pitch circle of the second teeth smaller than the diameter of the pitch circle of the first teeth, the module of the second teeth is made smaller than the module of the first teeth, so that the number of teeth of the output gear meshing with the second teeth can be reduced. Therefore, compared to when the number of teeth of the output gear is the same, the groove width between adjacent teeth in the output gear, in other words, the gap, is expanded. In the fifth aspect, the volume of the fluid that can be accumulated in the storage space can be increased by the amount of the expanded gap. For example, when the accumulated fluid is a lubricating fluid, the volume of the lubricating fluid that can be held in the storage space is increased, so that the lubricity of the motor-operated valve can be improved.

[0018] The planetary gear type reduction mechanism of the sixth aspect includes a planetary gear having first teeth to which an input rotation from an outside is input and second teeth that are arranged to correspond to the first teeth and have a module different from the module of the first teeth, and an output gear that meshes with the second teeth and outputs an output rotation that is reduced from the input rotation.

[0019] The planetary gear reduction mechanism of the sixth aspect, like the electric valve of the first aspect, is not restricted by the condition that the module of the first tooth and the module of the second tooth be the same, thereby improving the design freedom of the planetary gear reduction mechanism. Effect of the Invention

[0020] The motor-operated valve according to the present disclosure provides a new technology that can improve the design freedom in a motor-operated valve and a planetary gear type reduction mechanism, and also provides a method for assembling the motor-operated valve using this technology. [Brief description of the drawings]

[0021] [Figure 1] 1 is a cross-sectional view illustrating an embodiment of a motor-operated valve according to the present disclosure, taken along a plane including a central axis that is a rotation axis. [Diagram 2] FIG. 2 is a partially cutaway perspective view illustrating the inside of a paradox planetary gear type reduction mechanism in the motor-operated valve according to the present embodiment. [Diagram 3]FIG. 4 is a plan view illustrating an input region of the paradox planetary gear reduction mechanism according to the embodiment. [Figure 4] FIG. 4 is a plan view illustrating an output region of the paradox planetary gear reduction mechanism according to the embodiment. [Diagram 5] FIG. 2 is a perspective view illustrating a planetary gear of the paradox planetary gear type reduction mechanism according to the embodiment. [Figure 6] FIG. 2 is a front view illustrating a planetary gear of the paradox planetary gear type reduction mechanism according to the embodiment. [Figure 7] FIG. 4 is a bottom view illustrating the planetary gear of the paradox planetary gear type reduction mechanism according to the embodiment, viewed from the second tooth side. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0022] The present embodiment will be described below. In the following description of the drawings, the same or similar parts are given the same or similar symbols. However, the drawings are schematic, and the relationship between thickness and planar dimensions, the thickness ratio of each device and each member, etc. may differ from the actual ones. Therefore, the specific thickness and dimensions should be determined by taking into consideration the following description. In addition, there may be parts with different dimensional relationships and ratios between the drawings. In addition, unless otherwise specified in the specification, the number of each component of the present disclosure is not limited to one, and there may be more than one.

[0023] <Configuration of motor-operated valve> The motor-operated valve according to the present embodiment has a basic structure including a drive unit, a reduction mechanism as a gear reducer unit, a screw mechanism unit, and a valve body unit. The drive unit has an excitation function and includes a motor composed of a stator and a rotor. The drive unit includes an electric motor.

[0024] The reduction mechanism performs gear reduction by inputting a rotational driving force from the drive unit, and outputs the reduced rotation. That is, in the reduction mechanism, the input rotation input from the drive unit is reduced in speed to form an output rotation, and the output rotation is output to the screw mechanism. The reduction mechanism (reduction device) includes a planetary gear type reduction mechanism (planetary gear type reduction device).

[0025] The screw mechanism converts the reduced rotation from the reduction mechanism, i.e., the output rotation, into a displacement in the screw axis direction by the screw action and outputs it. The valve body controls the opening of the valve by moving the valve disc toward and away from the valve seat in response to the displacement output in the screw axis direction from the screw mechanism. Each of the components will be described below with reference to Figure 1.

[0026] (Drive unit) As shown in FIG. 1, the drive section of the motor-operated valve 1 according to this embodiment includes a can 30, a motor excitation device 2, and a rotor assembly 50.

[0027] (Can) The can 30 is a cylindrical closed-top pressure vessel fixed to the valve body 10. The can 30 is a cylindrical closed-top pressure vessel made of a non-magnetic metal material. The lower end of the can 30 in FIG. 1 abuts against the periphery of the receiving member 20 provided on the valve body 10.

[0028] The can 30 is fixed to the valve body 10 via a receiving member 20. The valve body 10 has a valve chamber 12 formed in the lower part and an orifice 14 extending downward from the bottom of the valve chamber 12. A refrigerant pipe 18A communicating with the side surface of the valve chamber 12 and a refrigerant pipe 18B communicating with the lower end of the orifice 14 are fixed to the valve body 10. A rotor assembly 50 mounted inside the can 30 rotates when a drive signal is supplied to the coil 3 of the motor excitation device 2.

[0029] (Motor Exciter) The motor excitation device 2 is attached to the outside of the can 30 by a mounting fixture 5 formed of a leaf spring in a detachable fit state with respect to the can 30. In the motor excitation device 2, a coil 3 constituting a stator of the motor is molded integrally with resin. The motor excitation device 2 has a resin mold, a coil 3 wound around a bobbin provided inside the resin mold, and a stator that is excited by passing current through the coil 3, and the coil 3 is connected to an external power source via an electric circuit 4 and lead wires to receive power. The reference numerals of the resin mold in FIG. 1 have been omitted for ease of viewing.

[0030] (bearings, shafts) The bearing 40 has a hat-shaped or disk-shaped cross section with a hole 41 in the center. The bearing 40 is inserted inside the top of the can 30 and disposed on the inner surface of the can 30. A shaft 42 is inserted into the hole 41 of the bearing 40. A rotor assembly 50, which is a permanent magnet rotor of the stepping motor, is disposed inside the can 30 so as to be freely rotatable by the shaft 42.

[0031] (Rotor Assembly) The rotor assembly 50 is rotatably supported within the can 30. The rotor assembly 50 is of a permanent magnet type that is rotationally driven by the motor excitation device 2. The motor excitation device 2 is an excitation device for a stepping motor, which is an example of an electric motor.

[0032] The rotor assembly 50 is formed in a cylindrical shape with an upper end from a plastic material containing a magnetic material, and is molded integrally with a sun gear member 54 disposed in the center. A boss (not shown) extending vertically downward is provided in the center of the sun gear member 54. The boss has a through hole 58 for the shaft 42. A sun gear 56, which is one component of a reduction mechanism 60, is formed on the outside of the boss.

[0033] (Gear case) The gear case 61 is a cylindrical member. A lower portion of the gear case 61 is fitted into an upper portion of the holder 72. An upper portion of the gear case 61 is bent toward the fixed gear 62. The gear case 61 is made of metal or the like.

[0034] The bent portion of the gear case 61 comes into contact with the outer surface of the fixed gear 62 made of resin or the like. In this embodiment, the fixed gear 62 is fixed to the gear case 61 by crimping. That is, the fixed gear 62 is locked at the bent portion of the gear case 61. The gear case 61 houses the reduction mechanism 60. The gear case 61 may be included in the reduction mechanism 60.

[0035] (Operation of the reduction mechanism) In the reduction mechanism 60, the sun gear 56 of the rotor assembly 50 functions as an input gear. The planetary gear 65 supported by the carrier 64 meshes with the sun gear 56, and also meshes with the fixed gear 62 (more precisely, a ring gear (fixed side internal gear) 62A formed on the inner circumferential surface of the fixed gear 62, see FIG. 2) and the output gear 66 (more precisely, an output side internal gear 66D formed on the inner circumferential surface of the output gear 66, see FIG. 2). The entire carrier 64 is supported on the output gear 66 so as to be able to rotate freely.

[0036] The ring gear 62A and the output side internal gear 66D have different numbers of teeth, but are both configured to mesh with the planetary gear 65. To achieve this meshing, the profile shift coefficients of the ring gear 62A and the output side internal gear 66D are set to appropriate values. When the planetary gear 65 rotates and revolves while meshing with the ring gear 62A of the fixed gear 62, the output gear 66 rotates relative to the fixed gear 62 based on the difference in the numbers of teeth.

[0037] Therefore, in the reduction mechanism 60, the input rotation from the sun gear 56 is reduced and output to the output gear 66, resulting in a large reduction ratio of, for example, about 50:1. Therefore, the rotation speed of the rotor assembly 50 is reduced, for example, to 1 / 50, and transmitted to the screw shaft 71 via the output shaft 70. As a result, the screw shaft 71 can rotate at a very small rotation speed. Therefore, the valve opening can be controlled with high resolution.

[0038] (reduction ratio) A description will be given of the reduction ratio when the number of teeth of the output side internal gear 66D of the output gear 66 is greater than the number of teeth of the ring gear 62A in the reduction mechanism 60. When the sun gear 56 rotates clockwise (CW) together with the rotor assembly 50 by the operation of the motor excitation device 2, the planetary gear 65 meshing with the sun gear 56 and the ring gear 62A rotates counterclockwise (CCW), in other words, revolves around the sun gear 56 while rotating on its axis.

[0039] As a result, the carrier 64 is decelerated and rotates clockwise (CW). The output gear 66 meshing with the planetary gear 65 is further decelerated and rotates clockwise (CW) based on the difference in the number of teeth between the ring gear 62A (see FIG. 2) and the output side internal gear 66D (see FIG. 2). When the numbers of teeth of the sun gear 56, the planetary gear 65, the ring gear 62A of the fixed gear 62, and the output side internal gear 66D of the output gear 66 in the reduction mechanism 60 are Z1, Z2, Z3, and Z4, respectively, the output gear ratio of the output gear 66, i.e., the reduction ratio, is expressed by the following formula (1).

[0040] Reduction ratio=[Z4·(Z1+Z3)] / [Z1·(Z4-Z3)] ···(1) However, Z3 ≠ Z4

[0041] Moreover, the above equation (1) can also be expressed as the following equation (2) by dividing the numerator and denominator on the right-hand side by (Z1·Z4). Reduction ratio=(1+Z3 / Z1) / (1-Z3 / Z4) ···(2)

[0042] The smaller the difference between the number of teeth of the ring gear 62A of the fixed gear 62 and the number of teeth of the output side internal gear 66D of the output gear 66, the larger the reduction ratio can be. Therefore, when it is desired to increase the reduction ratio, for example, if the number of planetary gears is 3, it is possible to set [Z4-Z3]=3. Also, the larger Z3 / Z1 is, the larger the reduction ratio can be obtained. Therefore, in order to reduce the number of teeth Z1 of the sun gear 56 and obtain the required reduction ratio, the number of teeth Z3 of the ring gear 62A, the number of teeth Z4 of the output side internal gear 66D, and the number of teeth Z2 of the planetary gear 65 are each determined.

[0043] For example, when Z1=12, Z2=18, Z3=48, and Z4=54 are set, the output gear ratio of the output gear 66 is a large reduction ratio of 1 / 45. Since the rotation of the rotor assembly 50 is transmitted to the screw shaft 71 at a large reduction ratio of 1 / 45, it becomes possible to control the valve opening minutely, i.e., with high resolution.

[0044] (Output shaft) 1, the output shaft 70 is a cylindrical member having a bottomed first hole 70A for receiving the shaft 42, and a second hole 70B (for example, a slot or a slit-like groove) formed on the opposite side to the first hole 70A. As shown in FIG. 1, the rotation of the output shaft 70 is transmitted to the shaft 42 by inserting a flat plate-like protrusion 71A of the screw shaft 71 into the second hole 70B.

[0045] (piping, holder) Two pipes 18A, 18B are attached to the valve body 10 in an airtight or liquidtight manner. A holder 72 is provided on the upper side of the valve body 10. In the motor-operated valve 1 according to this embodiment, the valve body 10 and the holder 72 are integrally manufactured using the same material. Note that the present disclosure is not limited to this, and the valve body and the holder may be manufactured separately using different materials and then integrated by welding or the like.

[0046] The holder 72 is a cylindrical member. The outer diameter of the holder 72 is smaller than the outer diameter of the valve body 10, and the outer edge of the valve body 10 is located radially outward from the outer edge of the holder 72. A shoulder portion of the valve body 10 is formed at the boundary height between the valve body 10 and the holder 72.

[0047] (Receiving member) The lower surface of a ring-shaped receiving member 20 is welded to the upper surface of the shoulder portion of the valve body 10. The outer portion of the receiving member 20 is located outside the outer edge of the valve body 10.

[0048] With the bearing 73 fitted inside the holder 72, the holder 72 and the bearing 73 are integrated by press-fitting, crimping, or the like. The gear case 61 is attached in a fitted state to the upper side of the holder 72. A protrusion 71A is provided on the upper part of the screw shaft 71. The protrusion 71A is inserted into a second hole 70B of the output shaft 70 of the reduction mechanism 60. A ball 74 is fixed to a recess 71B at the lower part of the screw shaft 71. The rotation of the screw shaft 71 is converted into a movement along the screw axis direction which is parallel to the central axis X in FIG. 1, and is transmitted to the valve rod 75 side via the ball 74.

[0049] (Screw mechanism) The screw mechanism of the motor-operated valve 1 uses a feed screw mechanism to convert the rotation of the output shaft 70 of the reduction mechanism 60 into linear motion that moves the valve body 76 toward and away from the valve seat 17, and transmits the motion to the valve rod 75. The screw mechanism of this embodiment includes a screw shaft 71. The screw shaft 71 screws into threads formed on the inner surface of a cylindrical bearing 73. The screw mechanism drives the screw shaft 71.

[0050] The bearing may be formed integrally with the holder by using the same member, and in the case where the bearing and the holder are formed integrally, the output gear 66 (output shaft 70) is supported directly by the holder 72.

[0051] (Valve body) The valve body of the present embodiment includes a screw shaft 71, a ball 74, a ball receiving member 74A, a valve stem 75, and a valve body 76. The valve body may also include a valve body 10, a valve chamber 12, and an orifice 14.

[0052] In the valve body of the motor-operated valve 1, the movement of the screw shaft 71 is transmitted to the valve rod 75 via the ball 74 and the ball receiving member 74A, and as a result, the valve element 76 attached to the tip of the valve rod 75 moves linearly along the vertical direction (the direction of the central axis X) in FIG. 1. This controls the flow path area between the valve element 76 and the orifice 14, and as a result, adjusts the flow rate of the refrigerant. In addition, a spring receiving member 26 is attached across the valve rod 75 and the valve body 10. As will be described later, the spring receiving member 26 has the function of supporting the lower end of the compression coil spring 24 that urges the valve element 76 upward, and the function of acting as a sliding guide when the valve element 76 moves up and down.

[0053] (Valve body) A valve chamber 12 is formed inside the valve body 10, and a valve seat 17 is formed as part of the wall surface that defines the valve chamber 12. An orifice 14 that communicates with the valve chamber 12 is formed in the valve body 10. In addition, a pipe 18A that communicates with the valve chamber 12 and a pipe 18B that communicates with the orifice 14 are attached to the valve body 10 in an air-tight or liquid-tight manner.

[0054] (Valve stem) A valve element 76 is disposed inside the valve chamber 12. The valve element 76 moves toward and away from the valve seat 17 to open and close an opening formed in the valve seat 17. In other words, the valve element 76 is capable of opening and closing the opening of the valve seat 17. In order to move the valve element 76, a valve rod 75 linked to a screw shaft 71 of the screw mechanism is connected to the valve element 76.

[0055] (Spring support member) The spring receiving member 26 is cylindrical. As shown in Fig. 1, the spring receiving member 26 has a small diameter portion 26A, a large diameter portion 26B located above the small diameter portion 26A and having a larger diameter than the small diameter portion 26A, and a flange-shaped portion 26C extending horizontally from the edge of the upper end of the large diameter portion 26B. A step portion 26D is formed at the boundary between the small diameter portion 26A and the large diameter portion 26B.

[0056] The small diameter portion 26A is disposed inside the valve chamber 12. The outer surface of the large diameter portion 26B contacts the inner surface of the valve body 10. The lower surface of the flange portion 26C in FIG. 1 contacts the step at the boundary between the valve body 10 and the holder 72 inside the valve body 10. The upper surface of the flange portion 26C in FIG. 1 contacts the lower surface of the bearing 73. The flange portion 26C is sandwiched between the bearing 73 and the valve body 10, thereby fixing its position inside the valve body 10. The valve stem 75 is inserted into the inside of the spring receiving member 26 so as to be able to slide freely.

[0057] As shown in Fig. 1, the lower part of the side surface of the valve stem 75 contacts the inner surface of the small diameter portion 26A. A compression coil spring 24 is disposed between the upper part of the side surface of the valve stem 75 in Fig. 1 and the inner surface of the large diameter portion 26B. The lower winding end of the compression coil spring 24 in Fig. 1 contacts the upper surface of the step portion 26D at the boundary between the small diameter portion 26A and the large diameter portion 26B. The upper winding end of the compression coil spring 24 in Fig. 1 contacts the brim-shaped spring receiving portion 75A provided at the upper portion of the valve stem 75.

[0058] A ball receiving member 74A of a ball 74 is inserted and fixed to the upper end of the valve stem 75. As shown in Fig. 1, the screw shaft 71 abuts against the upper part of the ball 74. The ball 74 transmits axial thrust to the valve stem 75 side by the screw mechanism.

[0059] 1 illustrates a state in which the motor-operated valve 1 is closed as a result of the valve stem 75 descending due to the output rotation from the reduction gear mechanism 60 and the valve element 76 reaching its lowest point. On the other hand, when the output rotation is reversed from the state illustrated in FIG. 1, the valve stem 75 rises due to the biasing force of the compression coil spring 24, and as a result, the motor-operated valve 1 is opened.

[0060] (Planetary Gear Reduction Mechanism) Next, the reduction mechanism 60 according to this embodiment will be described in more detail with reference to Fig. 2 to Fig. 7. The reduction mechanism 60 according to this embodiment is a paradox planetary gear type reduction mechanism. Note that in the present disclosure, the reduction mechanism is not limited to the paradox planetary gear type reduction mechanism, and may be another planetary gear type reduction mechanism (planetary gear type reduction device).

[0061] 2, in this embodiment, the reduction gear mechanism 60 can be divided into an upper input region R1 and a lower output region R2 along the axial direction. The sun gear 56, a first tooth T1 of the planetary gear 65, and the fixed gear 62 are arranged in the input region R1. The second tooth T2 of the planetary gear 65 and the output gear 66 are arranged in the output region R2.

[0062] In the input region R1, the input rotation from the motor excitation device 2 as an electric motor is input to the sun gear 56 meshing with the first tooth T1 of the planetary gear 65. In the output region R2, the output rotation is output to the output shaft 70 from the output gear 66 meshing with the second tooth T2 of the planetary gear 65.

[0063] (Fixed gear) The fixed gear 62 is in the shape of a ring, for example, made by molding resin. For example, a flange (not shown) may be formed on the outer periphery of the fixed gear 62, and concave portions (not shown) and convex portions (not shown) for fixing to the upper part of the gear case 61 may be formed alternately in the circumferential direction. As shown in Fig. 2, a ring gear 62A is formed on the inner periphery side of the fixed gear 62.

[0064] The fixed gear 62 has a number of teeth different from the number of teeth of the output gear 66. The tooth root diameter of the fixed gear 62 in this embodiment is, for example, a diameter of 15 mm or less. Note that in the present disclosure, the tooth root diameter of the fixed gear 62 is not limited to this and can be set arbitrarily.

[0065] (Sun Gear) As shown in Fig. 2, the sun gear 56 is disposed concentrically with the fixed gear 62. An input rotation is input to the sun gear 56. The sun gear 56 meshes only with a first tooth T1 of the planetary gear 65. For ease of viewing, the carrier 64 illustrated in Fig. 1 is omitted in Fig. 2.

[0066] (Career) The carrier 64 is formed, for example, by molding plastic, and comprises a pair of disks, each having a hole in the center through which the shaft 42 passes. Three masts extending upward and three partitions are arranged alternately in the circumferential direction on the peripheral portion of the upper surface of the disks. The carrier 64 constitutes the reduction mechanism 60. Three planetary gears 65 are rotatably supported by the carrier 64. Illustrations of the holes, masts, and partitions of the carrier 64 are omitted for ease of viewing.

[0067] (Output gear) 2, the output gear 66 is a cylindrical member with a bottom, having a bottom 66A and a wall portion 66B rising from the periphery of the bottom portion 66A. A hole 66C into which the cylindrical portion 70C of the output shaft 70 is press-fitted is formed in the center of the bottom portion 66A. An output side internal gear 66D is formed on the inner periphery of the output gear 66, so that the output gear 66 constitutes a ring gear. The output gear 66 is provided in the output region R2, and meshes with the second teeth T2.

[0068] (Storage space) 4, a storage space S capable of storing a fluid is formed inside the output gear 66, which is a cylindrical member with a bottom. The fluid is, for example, a refrigerant that moves from the valve body 76 side to the output gear 66 as the motor-operated valve 1 is used, or grease, lubricant, refrigeration oil, etc. used in the reduction mechanism 60. In particular, the space inside the second tooth T2 where the sun gear 56 is not present is a space where no other gears are present even when the planetary gear reduction mechanism is driven, and is suitable for storing grease or lubricant.

[0069] In this embodiment, the bottom 66A and the wall 66B are not provided with any openings such as holes, and as a result, the fluid is prevented from leaking out from the storage space S. The output gear 66 with a bottom is disposed at the lowest stage in the reduction gear mechanism 60, so that a fluid such as a lubricating fluid can be accumulated in the inner storage space S.

[0070] (Planetary gear) The planetary gear 65 has a plurality of first teeth T1 arranged to be located in the input region R1, and a plurality of second teeth T2 arranged to be located in the output region R2 corresponding to each of the plurality of first teeth T1.

[0071] 3, each of the first teeth T1 is symmetrical about a first center line A1 in a plan view. The first center line A1 is an imaginary line that extends radially through the central axis V of the rotation of the planetary gear 65 and the center of the first tooth T1 in the circumferential direction on the first pitch circle C1.

[0072] As shown in Fig. 4, each of the second teeth T2 is symmetrical about a second center line A2 in a plan view. The second center line A2 is a virtual line extending in a radial direction passing through the central axis V of the rotation of the planetary gear 65 and the center in the circumferential direction on the second pitch circle C2 of the second teeth T2. Fig. 4 also illustrates an example of a groove width GT between teeth adjacent to each other in the circumferential direction on the pitch circle CT of the output side internal gear 66D of the output gear 66.

[0073] As shown in FIG. 5, the planetary gear 65 is a cylindrical member. A hole 65H is formed in the center of the planetary gear 65, which is rotatably fitted to the mast of the carrier 64. A first tooth T1 and a second tooth T2 are provided on the outer periphery of the planetary gear 65 as a gear portion. Although not shown, a washer-like plate having a hole in the plate, similar to the plate on the lower side, is placed on the upper surface of the carrier 64 on which the planetary gear 65 is fitted to each mast. In addition, the convex portions of the tops of the masts and the bulkhead are press-fitted into the holes in the plate, so that the planetary gear 65 is rotatably fixed to the carrier 64.

[0074] In this embodiment, the first tooth T1 and the second tooth T2 are integrally formed using the same material, for example, metal, in a single planetary gear 65. Note that in the present disclosure, the first tooth T1 and the second tooth T2 may be fabricated separately and then integrated with each other to form a single planetary gear.

[0075] 5 and 6, the second tooth T2 has a module different from the module of the first tooth T1. In other words, one planetary gear 65 has a portion where teeth having different modules are provided in two stages in the vertical direction in FIG.

[0076] As shown in Fig. 7, in the planetary gear 65 of this embodiment, the first center line A1 and the second center line A2 that correspond to each other overlap in a plan view. That is, the first center line A1 and the second center line A2 that correspond to each other are arranged parallel to each other in the same plane that includes the central axis V of the planetary gear 65 that is aligned in the vertical direction in Fig. 6. The number of teeth of the second teeth T2 is the same as the number of teeth of the first teeth T1.

[0077] However, as shown in FIG. 7, the diameter of the second pitch circle C2 of the second tooth T2 is smaller than the diameter of the first pitch circle C1 of the first tooth T1. Therefore, the module of the second tooth T2 is smaller than the module of the first tooth T1. Also, the total tooth height H2 of the second tooth T2 is lower than the total tooth height H1 of the first tooth T1. Also, the second groove width G2 of the second tooth T2 is narrower than the first groove width G1 of the first tooth T1. The groove width is the length measured along the circumferential direction of the groove formed between adjacent teeth in the circumferential direction.

[0078] In the present embodiment, the modules of the first tooth T1 and the second tooth T2 are made different from each other by changing only the diameter of the pitch circle, but the present disclosure is not limited to this. In the present disclosure, the modules of the first tooth T1 and the second tooth T2 may be made different from each other by changing only the number of teeth, or by changing both the number of teeth and the diameter of the pitch circle.

[0079] (How to assemble the motorized valve) Next, a method of assembling the motor-operated valve according to this embodiment will be described. First, the fixed gear 62, the output gear 66, and the planetary gear 65 are assembled to prepare the planetary gear type reduction mechanism 60.

[0080] Specifically, an assembler places the valve body 10 in a fixed state in advance on, for example, a workbench for assembly. Inside the valve body 10, components located below the reduction gear mechanism 60, such as the output shaft 70, the threaded shaft 71, a holder 72, a bearing 73, a ball 74, a ball receiving member 74A, a valve stem 75, and a valve body 76, are assembled. In addition, the protrusion 71A of the threaded shaft 71 is engaged with the second hole 70B of the output shaft 70, and the end of the shaft 42 on the output shaft 70 side is not inserted into the first hole 70A of the output shaft 70.

[0081] Next, the assembler places the output gear 66 so that the bottom part 66A is located on the lower side. The assembler also places the hole 66C of the output gear 66 concentrically with the first hole 70A of the output shaft 70. Next, the assembler stacks the fixed gear 62 concentrically on the upper side of the output gear 66.

[0082] Next, an assembler inserts the planetary gear 65 supported by the carrier 64 from the upper side of the fixed gear 62 together with the carrier 64, with the second teeth T2 side (the lower side in FIG. 5) as the leading end. As shown in FIG. 5, the planetary gear 65 has first teeth T1 provided on the upper side and second teeth T2 provided on the lower side corresponding to the first teeth T1. The second teeth T2 have the same number of teeth as the first teeth T1, and the diameter of the second pitch circle C2 of the second teeth T2 is smaller than the diameter of the first pitch circle C1 of the first teeth T1.

[0083] Then, the assembler meshes the first teeth T1 with the ring gear 62A of the fixed gear 62, and meshes the second teeth T2 with the output-side internal gear 66D of the output gear 66. That is, by inserting the planetary gear 65 into the space inside the fixed gear 62 and output gear 66 that are integrally arranged, the planetary gear 65, the fixed gear 62, and the output gear 66 are meshed continuously in time.

[0084] In the present embodiment, a case has been illustrated in which the step of inserting the planetary gear 65 into the space inside the fixed gear 62 and the output gear 66 is carried out after the step of integrating the output gear 66 and the fixed gear 62, but the order of the assembly steps is not limited to this in the present disclosure. In the present disclosure, the order of the assembly steps can be changed as appropriate, for example, so that the step of inserting the fixed gear 62 into the first tooth of the planetary gear 65 protruding from the output gear 66 is carried out after the step of inserting the second tooth of the planetary gear 65 into the output gear 66.

[0085] The assembler also inserts the sun gear member 54 from above the fixed gear 62 so that the sun gear 56 meshes with the three planetary gears 65 inside the carrier 64. Through the above series of steps, the planetary gear type reduction mechanism 60 according to this embodiment can be fabricated. The assembler also attaches other members such as the shaft 42 and the can 30 from above to the fabricated planetary gear type reduction mechanism 60, thereby assembling the motor-operated valve 1 according to this embodiment.

[0086] (Action and effect) In the motor-operated valve 1 according to this embodiment, the module of the first tooth T1 and the module of the second tooth T2 are different from each other. Therefore, the planetary gear type reduction mechanism can be designed without being restricted by the condition that the module of the first tooth and the module of the second tooth are the same, and therefore the degree of freedom in designing the planetary gear type reduction mechanism can be improved. Similarly, the degree of freedom in designing the motor-operated valve 1 according to this embodiment can be improved.

[0087] Moreover, in this embodiment, among the planetary gear type reduction mechanism, in particular, a paradox planetary gear type reduction mechanism including the fixed gear 62 and the sun gear 56 can be realized.

[0088] Moreover, in this embodiment, the degree of freedom in designing the small motor-operated valve 1 in which the tooth root circle diameter of the fixed gear 62 is 15 mm or less can be particularly improved.

[0089] Furthermore, in this embodiment, the degree of freedom in designing the motor-operated valve 1 can be particularly improved in that the rotor assembly and the planetary gear reduction mechanism are disposed in the space between the valve body and the can.

[0090] In this embodiment, a storage space S capable of accumulating a fluid is formed inside the cylindrical member. Here, for example, by configuring the second teeth T2 of the planetary gear 65 to have the same number of teeth as the first teeth and making the diameter of the second pitch circle C2 of the second teeth T2 smaller than the diameter of the first pitch circle C1 of the first teeth T1, the module of the second teeth T2 is made smaller than the module of the first teeth T1, so that the number of teeth of the output gear 66 meshing with the second teeth T2 can be reduced.

[0091] The volume of the storage space S increases by the amount corresponding to the reduction in the diameter of the second tooth T2. For example, when the fluid stored in the storage space S is a lubricating fluid, the volume of the lubricating fluid that can be held in the storage space S increases, thereby improving the lubrication of the motor-operated valve 1.

[0092] In addition, for example, when assembling a relatively small planetary gear type reduction mechanism, multiple planetary gears are often integrated by rotatably supporting them on one carrier. Because the planetary gears are rotatable, when the planetary gears are inserted into the output gear or fixed gear, it is difficult for the position of the tooth closest to the internal teeth of the output gear or fixed gear to engage with the internal teeth of the output gear or fixed gear. In other words, the teeth of the multiple planetary gears do not mesh with the internal teeth of the output gear or fixed gear in their current positional relationship.

[0093] For this reason, when inserting the gears, it is necessary to slightly rotate some or all of the multiple planetary gears while they are supported by the carrier, thereby changing the positional relationship of the planetary gear teeth so that they mesh with the internal teeth of the output gear or fixed gear.

[0094] In particular, when the numbers of teeth of the first and second teeth provided in two stages, upper and lower, are different in the planetary gear, the first teeth and the second teeth do not correspond one-to-one to each other. In other words, there are many teeth whose relative positional relationships are different between the first teeth and the second teeth so that the directions of the first center lines of the first teeth and the directions of the second center lines of the second teeth are randomly arranged. In particular, when the numbers of meshing teeth are prime to each other, the relative positional relationships of all teeth are different between the first teeth and the second teeth.

[0095] For this reason, when the number of teeth differs between the first and second teeth of the planetary gear, the task of changing the positional relationship of the planetary gear's teeth when the planetary gear is supported by the carrier and inserted into the output gear or fixed gear is very burdensome.

[0096] On the other hand, in this embodiment, even if the modules are different between the first tooth T1 and the second tooth T2, the number of teeth of the first tooth T1 is the same as the number of teeth of the second tooth T2. Therefore, when the planetary gear 65 is inserted into the output gear 66 or the fixed gear 62 in a state in which the planetary gear 65 is supported by the carrier 64, the burden of the work of changing the positional relationship of the teeth of the planetary gear 65 can be reduced compared to the case in which the number of teeth of the first tooth T1 and the second tooth T2 are different.

[0097] In addition, in this embodiment, since the number of teeth of the output gear 66 that mesh with the second tooth T2 can be reduced, the gap between adjacent teeth on the output gear 66 is wider than when the number of teeth of the output gear 66 is the same. Therefore, it is easier to insert the planetary gear 65 into the output gear 66 and the fixed gear 62.

[0098] In particular, the smaller the motor-operated valve, the smaller the gap between adjacent teeth on the output gear 66 tends to be, making it more difficult to insert the planetary gear 65 into the output gear 66 and the fixed gear 62 during assembly. In order to improve the ease of insertion of the planetary gear 65, for example, a method of narrowing the lower end of the teeth so that the overall tooth height becomes lower as the shape of the lower part of the teeth of the planetary gear 65 goes downward is conceivable, but the reduced volume of the teeth tends to reduce the strength, i.e., the durability of the motor-operated valve. The present embodiment is advantageous in that it is possible to improve the ease of insertion of the planetary gear 65 without the need to reduce the volume of the teeth. <Other embodiments>

[0099] Although the present disclosure has been described by the above disclosed embodiments, the descriptions and drawings forming a part of this disclosure should not be understood as limiting the present disclosure. The present disclosure includes various embodiments not described above, and the technical scope of the present disclosure is defined only by the invention-specific matters in the claims that are appropriate from the above description. [Explanation of symbols]

[0100] 1 Motor-operated valve 2 Motor excitation device (electric motor) 3 Coil 4 Electrical Circuits 5 Mounting fixture 10 Valve body 12 Valve chamber 14 Orifice 17 Valve seat 18A, 18B piping 20 Receiving member 24 Compression coil spring 26 Spring support member 26A Small diameter section 26B Large diameter section 26C Collar 26D Step 30 Can 40 Bearings 41 holes 42 Shaft 50 Rotor assembly 54 Sun gear parts 56 Sun Gear 58 Through hole 60 Planetary gear reduction mechanism 61 Gear Case 62 Fixed Gear 62A Ring Gear 64 Career 65 Planetary Gear 65H hole 66 Output Gear 66A bottom 66B Wall section 66C hole 66D Output side internal gear 70 Output shaft 70A first hole 70B second hole 70C Cylinder section 71 Screw shaft 71A Protrusion 71B Recess 72 Holder 73 Bearings 74 Ball 74A Ball receiving member 75 Valve stem 75A Spring holder 76 Valve body A1 First center line A2 Second center line C1 First pitch circle C2 Second pitch circle CT output internal gear pitch circle G1 First groove width G2 Second groove width GT Output Internal Gear Groove Width H1 First tooth H2 Second tooth R1 Input area R2 output area S Storage space T1 First tooth T2 Second tooth V Planetary gear center axis X center axis

Claims

1. An electric motor; a planetary gear type reduction mechanism including: a planetary gear including first teeth to which an input rotation of the electric motor is input and second teeth provided corresponding to the first teeth and having a module different from that of the first teeth; and an output gear meshing with the second teeth and outputting an output rotation reduced in speed from the input rotation; a valve body portion for controlling the opening degree of the valve by the output rotation; An electrically operated valve comprising:

2. The planetary gear reduction mechanism includes: a fixed gear having a number of teeth different from the number of teeth of the output gear; a sun gear that is concentrically disposed with the fixed gear and receives the input rotation and meshes with the first tooth of the planetary gear; Equipped with The motor-operated valve according to claim 1.

3. The tooth root diameter of the fixed gear is 15 mm or less. The motor-operated valve according to claim 2.

4. a valve body having a valve chamber formed therein; a valve seat having an opening formed in a part of a wall surface of the valve chamber; a valve body arranged to be capable of opening and closing the opening of the valve seat; a valve stem for moving the valve body toward and away from the valve seat; A cylindrical can that is attached to the valve body and forms a space between the valve body and the cylindrical can; an excitation device for the electric motor attached to an outer periphery of the can; a permanent magnet type rotor assembly rotatably supported inside the can and rotated by the excitation device; a screw mechanism that converts the output rotation from the planetary gear type reduction mechanism into a contact and separation motion of the valve body with respect to the valve seat and transmits the contact and separation motion to the valve rod; the rotor assembly and the planetary gear type reduction mechanism are disposed in the space between the valve body and the can. The motor-operated valve according to any one of claims 1 to 3.

5. the output gear is a cylindrical member having a bottom and a wall rising from a peripheral edge of the bottom, A storage space capable of storing a fluid is formed inside the cylindrical member. The motor-operated valve according to claim 4.

6. a planetary gear including a first tooth to which an input rotation from an outside is input and a second tooth provided corresponding to the first tooth and having a module different from that of the first tooth; and an output gear meshing with the second tooth to output an output rotation obtained by reducing the speed of the input rotation; A planetary gear type reduction mechanism having the above structure.

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