Electric valve and planetary gear 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 motor-operated valve that opens and closes a valve via an electric motor, in which the input rotation of a rotor is reduced by a planetary gear reduction mechanism and the reduced output rotation is transmitted to a screw mechanism that controls the opening and closing of the valve. 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] Furthermore, 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 that meshes with the fixed gear is referred to as the “first tooth,” and the tooth 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, the module of the first tooth and the module of the second tooth are the same in one planetary gear.

[0006] For this reason, the design of not only the planetary gears but also the designs of other gear elements that mesh with the planetary gears, such as the sun gear, fixed gear, and output gear, is limited by 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 in that the degree of freedom in designing a planetary gear type reduction mechanism and the degree of freedom in designing an electric valve that uses a planetary gear type reduction mechanism are reduced overall.

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

[0008] The electric valve according to the first aspect comprises: an electric motor; a planetary gear type reduction mechanism having a planetary gear with first teeth to which the 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 from the input rotation; and a valve main body that controls the opening degree of the valve by the output rotation.

[0009] In the electric 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 must be the same, thereby improving the design freedom of the electric valve.

[0010] In a second aspect, in the electric valve of the first aspect, the planetary gear reduction mechanism comprises 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 reduction mechanism that includes a fixed gear and a sun gear, among other planetary gear reduction mechanisms.

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

[0014] A fourth aspect is an electrically operated 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 element arranged to be able to open and close the opening of the valve seat; a valve stem moving the valve element 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 can; an excitation device for the electric motor attached to the outer periphery of the can; a permanent magnet type rotor assembly rotatably supported inside the can and rotationally driven by the excitation device; and a screw mechanism that converts the output rotation from the planetary gear reduction mechanism into an approaching and separating movement of the valve element relative to the valve seat and transmits the rotation to the valve stem, 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, especially in a motor-operated valve 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] In a fifth aspect, in an electric valve according to any one of the first to fourth aspects, the output gear is a bottomed cylindrical 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 cylindrical member.

[0017] Here, for example, by configuring the number of second teeth of the planetary gear to be the same as the number of first teeth, but making the pitch diameter of the second teeth smaller than the pitch diameter of the first teeth, the module of the second teeth can be made smaller than the module of the first teeth, thereby reducing the number of teeth of the output gear that mesh with the second teeth. As a result, the groove width between adjacent teeth on the output gear, in other words, the gap, is wider than when the number of teeth on the output gear is the same. In the fifth aspect, the wider gap allows the volume of fluid that can be stored in the storage space to be increased. For example, if the fluid to be stored is a lubricating fluid, the volume of lubricating fluid that can be held in the storage space increases, thereby improving the lubricity of the motor-operated valve.

[0018] The planetary gear type reduction mechanism according to the sixth aspect includes a planetary gear having first teeth to which an input rotation from an external source is input, and second teeth that correspond to the first teeth and have a module different from that 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] In the planetary gear reduction mechanism of the sixth aspect, as in the case of the electric valve of the first aspect, it is not restricted by the condition that the module of the first tooth and the module of the second tooth must be the same, thereby improving the design freedom of the planetary gear reduction mechanism. [Effects of the Invention]

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

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

[0022] This embodiment will be described below. In the following description of the drawings, identical or similar parts are designated by the same or similar reference numerals. However, the drawings are schematic, and the relationship between thickness and planar dimensions, the thickness ratio of each device or component, etc. may differ from the actual ones. Therefore, specific thicknesses and dimensions should be determined with reference to the following description. Furthermore, there may be parts with different dimensional relationships and ratios between the drawings. Furthermore, unless otherwise specified in the specification, the number of each component element of the present disclosure is not limited to one, and multiple elements may be present.

[0023] <Motor-operated valve configuration> The motor-operated valve according to this embodiment has a basic structure including a drive unit, a reduction mechanism as a gear reducer, a screw mechanism, and a valve body. The drive unit functions as an excitation motor and includes a motor consisting of a stator and a rotor.

[0024] The reduction mechanism performs gear deceleration by receiving a rotational driving force from the drive unit and outputs the decelerated rotation. That is, the reduction mechanism generates output rotation by decelerating the input rotation input from the drive unit, and outputs the output rotation 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 through the screw action and outputs it. The valve body controls the valve opening 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 component will be explained 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 closed-ended cylindrical pressure vessel fixed to the valve body 10. The can 30 is a closed-ended cylindrical 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 its 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. The 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 exciter 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 relative to the can 30. In the motor exciter 2, the coil 3 constituting the motor stator is molded integrally with resin. The motor exciter 2 has a resin mold, the coil 3 wound around a bobbin installed 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 clarity.

[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 is 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 rotatable by the shaft 42.

[0031] (Rotor assembly) The rotor assembly 50 is rotatably supported within the can 30. The rotor assembly 50 is 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 a top 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 the reduction mechanism 60, is formed on the outside of the boss.

[0033] (Gear case) The gear case 61 is a cylindrical member. The lower part of the gear case 61 is fitted into the upper part of the holder 72. The upper part of the gear case 61 is bent towards 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 caulking. 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 gears 65 supported by the carrier 64 mesh with the sun gear 56, and also mesh 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 so as to be able to rotate freely on the output gear 66.

[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 addendum 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 due to the difference in the number 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. As a result, 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. This makes it possible to control the valve opening with high resolution.

[0038] (reduction ratio) The following describes 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 due to 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 own axis.

[0039] As a result, the carrier 64 is decelerated and rotates clockwise (CW). The output gear 66 meshing with the planetary gears 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 gears 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 equation (1).

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

[0041] The above equation (1) can also be expressed as the following equation (2) by dividing the numerator and denominator on the right 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 a larger reduction ratio is desired, for example, if the number of planetary gears is three, it can be set as [Z4 - Z3] = 3. Furthermore, the larger Z3 / Z1 is, the larger the reduction ratio that can be obtained. Therefore, the number of teeth Z1 of the sun gear 56 is reduced, and 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 gears 65 are each determined to obtain the required reduction ratio.

[0043] For example, when Z1 = 12, Z2 = 18, Z3 = 48, and Z4 = 54, the output gear ratio of the output gear 66 is a large reduction ratio of 1 / 45. Because 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 that receives the shaft 42 and a second hole 70B (for example, a slot or slit-like groove) formed on the opposite side of 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. However, 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 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, caulking, 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 bottom of the screw shaft 71. The rotation of the screw shaft 71 is converted into movement along the screw axis direction, which is parallel to the central axis X in FIG. 1, and is transmitted to the valve stem 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 speed reduction mechanism 60 into linear motion that moves the valve element 76 toward and away from the valve seat 17, and transmits this to the valve stem 75. The screw mechanism of this embodiment includes a screw shaft 71. The screw shaft 71 is threadedly engaged with 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 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 this 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 stem 75 via the ball 74 and the ball receiving member 74A, causing the valve element 76 attached to the tip of the valve stem 75 to move linearly in 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, thereby regulating the flow rate of the refrigerant. In addition, a spring receiving member 26 is attached across the valve stem 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 for the valve element 76 as it 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 forms 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 airtight or liquidtight 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 can open and close the opening of the valve seat 17. In order to move the valve element 76, a valve rod 75 linked to the screw shaft 71 of the screw mechanism is connected to the valve element 76.

[0055] (Spring support member) 1, spring receiving member 26 has a small diameter portion 26A, a large diameter portion 26B located above small diameter portion 26A and having a larger diameter than small diameter portion 26A, and a flange-shaped portion 26C extending horizontally from the upper edge of large diameter portion 26B. A step portion 26D is formed at the boundary between small diameter portion 26A and 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. A valve stem 75 is slidably inserted inside the spring receiving member 26.

[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 a flange-shaped spring seat 75A provided at the upper part 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 top of the ball 74. The ball 74 transmits axial thrust to the valve stem 75 side via the screw mechanism.

[0059] 1 illustrates a state in which the valve stem 75 descends due to the output rotation from the speed reduction mechanism 60, and the valve element 76 reaches its lowest point, thereby closing the motor-operated valve 1. 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 opens.

[0060] (Planetary gear reduction mechanism) Next, the reduction mechanism 60 according to this embodiment will be described in more detail with reference to Figures 2 to 7. The reduction mechanism 60 according to this embodiment is a paradox planetary gear reduction mechanism. Note that in the present disclosure, the reduction mechanism is not limited to a paradox planetary gear reduction mechanism, and may be another planetary gear reduction mechanism (planetary gear 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, the 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, 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, 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 recesses (not shown) and protrusions (not shown) for fixing the fixed gear 62 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 of the fixed gear 62.

[0064] The fixed gear 62 has a number of teeth that differs from the number of teeth of the output gear 66. In this embodiment, the root diameter of the fixed gear 62 is, for example, 15 mm or less. However, in the present disclosure, the 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. Input rotation is input to the sun gear 56. The sun gear 56 meshes only with the first tooth T1 of the planetary gear 65. For ease of viewing, the carrier 64 illustrated in Fig. 1 is omitted from Fig. 2.

[0066] (Career) The carrier 64 is formed, for example, by molding plastic, and includes a pair of disks, each having a hole in the center through which the shaft 42 passes. Three masts and three partitions extending upward are arranged alternately in the circumferential direction around the periphery 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. The holes, masts, and partitions of the carrier 64 are omitted from the illustration for clarity.

[0067] (output gear) 2, the output gear 66 is a cylindrical member with a bottom, having a bottom 66A and a wall 66B rising from the periphery of the bottom 66A. A hole 66C is formed in the center of the bottom 66A, into which the cylindrical portion 70C of the output shaft 70 is press-fitted. An output-side internal gear 66D is formed on the inner periphery of the output gear 66, and 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 may be, for example, a refrigerant that moves from the valve element 76 to the output gear 66 as the motor-operated valve 1 is used, or grease, lubricating oil, or refrigeration oil 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 therefore suitable for storing grease or lubricating oil.

[0069] In this embodiment, the bottom 66A and the wall 66B are not provided with any openings such as holes, which prevents the fluid from leaking out of the storage space S. The output gear 66 with a bottom is disposed at the lowest stage in the reduction 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 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] 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 an imaginary line that extends radially through the central axis V of rotation of the planetary gear 65 and the center of the second tooth T2 in the circumferential direction on the second pitch circle C2. FIG. 4 also illustrates an example of a groove width GT between adjacent teeth 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, into which the mast of the carrier 64 is rotatably fitted. First teeth T1 and second teeth T2 are provided on the outer periphery of the planetary gear 65 as a gear portion. Although not shown, a single washer-like plate having a hole in the plate, similar to the plate on the lower surface, is placed on the upper surface of the carrier 64, onto which the planetary gear 65 is fitted to each mast. Furthermore, the protrusions on the tops of the masts and the bulkhead are press-fitted into the hole in the plate, thereby rotatably fixing the planetary gear 65 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 the 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] 7, in the planetary gear 65 of this embodiment, the first center line A1 and the second center line A2 corresponding to each other overlap in a plan view. That is, the first center line A1 and the second center line A2 corresponding to each other are arranged parallel to each other in the same plane including the central axis V of the planetary gear 65 that is aligned in the up-and-down 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. Furthermore, the total tooth height H2 of the second tooth T2 is smaller than the total tooth height H1 of the first tooth T1. Furthermore, 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 in 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 for 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 form the planetary gear type reduction mechanism 60.

[0080] Specifically, an assembler places the valve body 10 in a fixed state on, for example, an assembly workbench. Inside the valve body 10, components located below the speed reduction mechanism 60, such as the output shaft 70, the threaded shaft 71, the holder 72, the bearing 73, the balls 74, the ball receiving member 74A, the valve stem 75, and the valve disc 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 positions the output gear 66 so that the bottom 66A is located on the bottom side. The assembler also positions 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 top of the output gear 66.

[0082] Next, the assembler inserts the planetary gear 65 supported by the carrier 64 from the upper side of the fixed gear 62, with the second teeth T2 side (the lower side in FIG. 5) at 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, which are integrally arranged, the planetary gear 65, fixed gear 62, and output gear 66 are meshed continuously in time.

[0084] In the present embodiment, the case has been exemplified 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 second tooth of the planetary gear 65 into the output gear 66 is carried out after the step of inserting the fixed gear 62 into the first tooth of the planetary gear 65 protruding from 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 components, 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. This allows the planetary gear reduction mechanism to be designed without being restricted by the requirement 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. Similarly, this also improves the design freedom of the motor-operated valve 1 according to this embodiment.

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

[0088] Furthermore, in this embodiment, the degree of freedom in designing the small motor-operated valve 1 in which the root 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 which 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 number of teeth of the second teeth T2 of the planetary gear 65 to be the same as the number of teeth of 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 can be made smaller than the module of the first teeth T1, thereby reducing the number of teeth of the output gear 66 that mesh with the second teeth T2.

[0091] The volume of the storage space S increases as the diameter of the second tooth T2 decreases. For example, if 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 lubricity of the motor-operated valve 1.

[0092] Furthermore, when assembling a relatively small planetary gear reduction mechanism, for example, multiple planetary gears are often integrated by rotatably supporting them on a single carrier. Because the planetary gears are rotatable, when inserting the planetary gears into the output gear or fixed gear, it is difficult for the teeth closest to the internal teeth of the output gear or fixed gear to mesh with the internal teeth of the output gear or fixed gear. In other words, the teeth of the multiple planetary gears and the internal teeth of the output gear or fixed gear do not mesh with each other if the teeth and grooves are in their original positional relationship.

[0093] Therefore, when inserting the gears, it is necessary to slightly rotate some or all of the 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 first and second teeth provided in two rows, upper and lower, on a planetary gear are different, the first teeth and the second teeth do not correspond one-to-one to each other. In other words, the relative positional relationships between the first and second teeth increase so that the directions of the first center lines of the first teeth and 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 between all of the first teeth and the second teeth are different.

[0095] Therefore, if the number of teeth differs between the first and second teeth of the planetary gear, when the planetary gear is supported by the carrier and inserted into the output gear or fixed gear, the work of changing the positional relationship of the planetary gear's teeth is a heavy burden.

[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 while the planetary gear 65 is supported by the carrier 64, the burden of changing the positional relationship of the teeth of the planetary gear 65 can be reduced compared to when the numbers of teeth of the first tooth T1 and the second tooth T2 are different.

[0097] Furthermore, in this embodiment, the number of teeth of the output gear 66 that mesh with the second tooth T2 can be reduced, and therefore the gaps between adjacent teeth on the output gear 66 are wider than when the number of teeth on the output gear 66 is the same. This makes it 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 gaps between adjacent teeth on the output gear 66 tend to be, making it more difficult to insert the planetary gear 65 into the output gear 66 and the fixed gear 62 during assembly. To improve ease of insertion of the planetary gear 65, it is possible to narrow the lower ends of the teeth so that the overall tooth height decreases as the shape of the lower part of the planetary gear 65 goes downward, but this reduces the volume of the teeth, which is likely to result in a decrease in strength, and therefore a decrease in the durability of the motor-operated valve. This embodiment is advantageous in that it improves 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 part of this disclosure should not be understood to limit 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 scope of the claims that are appropriate from the above description. [Explanation of symbols]

[0100] 1. Motor-operated valve 2 Motor excitation device (electric motor) 3 coils 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 internal gear 70 Output shaft 70A first hole 70B second hole 70C Cylinder 71 Screw shaft 71A Protrusion 71B Recess 72 Holder 73 Bearings 74 balls 74A Ball receiving member 75 Valve stem 75A spring support 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 the same number of teeth as that of the first teeth; an output gear that meshes with the second teeth and outputs an output rotation that is reduced from the input rotation; and a fixed gear that meshes with the first teeth and has a number of teeth different from that of the output gear. a valve body that controls the opening degree of the valve by the output rotation; An electric valve comprising:

2. The planetary gear reduction mechanism includes: 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 able to open and close the opening of the valve seat; a valve stem that moves the valve element toward and away from the valve seat; a cylindrical can attached to the valve body and forming a space between the can and the valve body; an excitation device for the electric motor attached to the outer periphery of the can; a permanent magnet 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 reduction mechanism into a movement of the valve disc toward or away from the valve seat and transmits the movement to the valve stem; 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 external source is input, and a second tooth provided corresponding to the first tooth and having a module different from that of the first tooth and the same number of teeth as that of the first tooth; an output gear that meshes with the second tooth and outputs an output rotation that is a reduced version of the input rotation; and a fixed gear that meshes with the first tooth and has a number of teeth different from that of the output gear. A planetary gear type reduction mechanism having the above structure.

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