Motor valve and planetary gear type speed reduction mechanism

Abstract

To provide a novel technology capable of increasing a speed reduction ratio in a motor valve and a planetary gear type speed reduction mechanism.SOLUTION: In n (n: natural number of 2 or more) planetary gears (first planetary gear 65A, second planetary gear 65B, third planetary gear 65C), preset phase differences (first phase difference D1, second phase difference D2) are formed between a first tooth T1 and a second tooth T2 of one planetary gear, and the difference between the phase difference of one planetary gear and the phase difference of the other planetary gear of the planetary gears adjacent to each other in a circumferential direction is (1 / n)(pitch width P of the second tooth T2).SELECTED DRAWING: Figure 6

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, 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, although it is not a motor-operated valve. In a planetary gear reduction mechanism, the smaller the difference in the number of teeth between the fixed gear and the output gear, the greater the reduction ratio that can be obtained. [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] In this specification, in one planetary gear, the teeth of a portion that meshes with the fixed gear are referred to as the “first teeth,” and the teeth of a portion that meshes with the output gear at a position different from the first teeth are referred to as the “second teeth.” In the cases of Patent Documents 1 and 2, in one planetary gear, the number of first teeth and the number of second teeth are the same.

[0006] In this specification, in a planetary gear, an imaginary line extending radially through the central axis of rotation of the planetary gear and the circumferential center on the pitch circle of the teeth in a plan view is referred to as a tooth center line. Also, in an output internal gear corresponding to the planetary gear, an imaginary line extending radially through the central axis of rotation of the planetary gear reduction mechanism and the circumferential center on the pitch circle of the groove between the teeth in a plan view is referred to as a groove center line.

[0007] In addition, when viewed in a plane, a state in which the center line of the first tooth and the center line of the second tooth overlap is referred to as "being in phase" or "no phase difference is formed," and a state in which the center line of the first tooth and the center line of the second tooth are misaligned is referred to as "being out of phase" or "a phase difference is formed."

[0008] Now consider n planetary gear teeth and the grooves of the output internal gear that mesh with each of the n planetary gears. n is a natural number greater than or equal to 2. The state in which the center lines of the planetary gear teeth and the center lines of the grooves of the output internal gear overlap at all meshing positions of the n planetary gears is when the number of grooves of the output internal gear, i.e., the number of teeth of the output internal gear, is an integer multiple of n (n k). k is a natural number. For this reason, in a differential gear mechanism, the minimum difference in the number of teeth between the fixed gear teeth and the output gear teeth cannot be made less than n.

[0009] In this regard, Patent Documents 1 and 2 also do not consider making the difference in the number of teeth smaller than n, and as a result, it is not possible to increase the reduction ratio.

[0010] In view of the above, the present disclosure provides a novel technique for increasing the reduction ratio in a motor-operated valve and a planetary gear type reduction mechanism. [Means for solving the problem]

[0011] The electric valve according to a first aspect comprises: an electric motor; n (n: a natural number of 2 or more) planetary gears each having a first tooth to which an input rotation of the electric motor is input and a second tooth provided corresponding to the first tooth; an output gear that meshes with the second tooth and outputs an output rotation obtained by reducing the input rotation; and a planetary gear type reduction mechanism that controls an opening degree of a valve by the output rotation, wherein in the n planetary gears, a diameter of a first pitch circle of the first tooth and a diameter of a second pitch circle of the second tooth are the same, the number of teeth of the first tooth and the number of teeth of the second tooth are the same, a preset phase difference is formed between the first tooth and the second tooth of one of the planetary gears, and a difference between the phase difference of one of the planetary gears adjacent to each other in the circumferential direction is (1 / n) · (pitch width of the second tooth).

[0012] Here, when the difference in the number of teeth between the fixed gear and the output gear is 1, at the meshing position of the second tooth, the phase difference between the center line of the second tooth and the center line of the groove of the output gear increases by (1 / n) · (pitch width of the output gear) in accordance with the order in which the planetary gears are arranged in the circumferential direction.

[0013] In the motor-operated valve according to the first aspect, the sum of the phase differences of the n planetary gears is preset to correspond to a distance of one pitch width of the output gear. Therefore, it is possible to set the minimum difference in the number of teeth between the number of teeth of the fixed gear meshing with the first teeth and the number of teeth of the output gear meshing with the second teeth to 1. Therefore, the difference in the number of teeth can be made smaller than n, and as a result, the reduction ratio of the planetary gear type reduction mechanism can be increased.

[0014] In a second aspect, in the electric valve of the first aspect, the planetary gear type reduction mechanism includes a fixed gear 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.

[0015] 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.

[0016] 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.

[0017] 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.

[0018] 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.

[0019] 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.

[0020] A planetary gear type reduction mechanism according to a fifth aspect includes n planetary gears (n: a natural number of 2 or more), each 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 an output gear that meshes with the second tooth and outputs an output rotation obtained by reducing the input rotation, wherein in the n planetary gears, a diameter of a first pitch circle of the first tooth and a diameter of a second pitch circle of the second tooth are the same, the number of teeth of the first tooth and the number of teeth of the second tooth are the same, a preset phase difference is formed between the first tooth and the second tooth of one of the planetary gears, and a difference between the phase difference of one of the planetary gears adjacent to each other in the circumferential direction is (1 / n) · (pitch width of the second tooth).

[0021] In the planetary gear type reduction mechanism according to the fifth aspect, the reduction ratio can be increased, similarly to the motor-operated valve according to the first aspect. Effect of the Invention

[0022] According to the motor-operated valve of the present disclosure, a new technique can be provided that can increase the reduction ratio in the motor-operated valve and the planetary gear type reduction mechanism. [Brief description of the drawings]

[0023] [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 plan view illustrating a planetary gear of the paradox planetary gear type reduction mechanism according to the embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0024] 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.

[0025] <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.

[0026] 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).

[0027] 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.

[0028] (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.

[0029] (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.

[0030] 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.

[0031] (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.

[0032] (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.

[0033] (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.

[0034] 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.

[0035] (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.

[0036] 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.

[0037] (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 supported by the carrier 64 meshes with the sun gear 56, and also meshes with the fixed gear 62 (more precisely, a ring gear 62A (fixed side internal gear) formed on the inner peripheral 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 peripheral surface of the output gear 66, see FIG. 2). In the cross-sectional view of FIG. 1, a first planetary gear 65A and a second planetary gear 65B are illustrated. The entire carrier 64 is supported so as to be freely rotatable on the output gear 66.

[0038] The ring gear 62A and the output side internal gear 66D have different numbers of teeth, but are configured to mesh with the first planetary gear 65A, the second planetary gear 65B, and the third planetary gear 65C. In order 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 first planetary gear 65A, the second planetary gear 65B, and the third planetary gear 65C rotate and revolve 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 number of teeth.

[0039] 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.

[0040] (reduction ratio) A description will be given of the reduction ratio in the reduction mechanism 60 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. When the sun gear 56 rotates clockwise (CW) together with the rotor assembly 50 by the operation of the motor excitation device 2, the first planetary gear 65A, the second planetary gear 65B, and the third planetary gear 65C meshed with the sun gear 56 and the ring gear 62A rotate counterclockwise (CCW), in other words, revolve around the sun gear 56 while rotating on their own axes.

[0041] As a result, the carrier 64 is decelerated and rotates clockwise (CW). The output gear 66 (see FIG. 2) meshing with the first planetary gear 65A, the second planetary gear 65B, and the third planetary gear 65C 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. When the numbers of teeth of the sun gear 56, the planetary gears (the first planetary gear 65A, the second planetary gear 65B, and the third planetary gear 65C), 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).

[0042] Reduction ratio=[Z4 (Z1+Z3)] / [Z1 (Z4-Z3)] (1) However, Z3 ≠ Z4

[0043] 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)

[0044] 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 necessary 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 gears (first planetary gear 65A, second planetary gear 65B, third planetary gear 65C) are each determined.

[0045] 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.

[0046] (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.

[0047] (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.

[0048] 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.

[0049] (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.

[0050] 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.

[0051] (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.

[0052] 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.

[0053] (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.

[0054] 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.

[0055] (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.

[0056] (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.

[0057] (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.

[0058] 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.

[0059] 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.

[0060] 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.

[0061] 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.

[0062] (Planetary Gear Paradox) 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).

[0063] 2, in this embodiment, the reduction mechanism 60 can be divided into an upper input region R1 and a lower output region R2 along the axial direction. In the input region R1, the sun gear 56, the first teeth T1 of the first planetary gear 65A, the second planetary gear 65B, and the third planetary gear 65C, and the fixed gear 62 are arranged. In the output region R2, the second teeth T2 of the first planetary gear 65A, the second planetary gear 65B, and the third planetary gear 65C, and the output gear 66 are arranged.

[0064] 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 teeth T1 of the first planetary gear 65A, the second planetary gear 65B, and the third planetary gear 65C. In the output region R2, the output rotation is output to the output shaft 70 from the output gear 66 meshing with the second teeth T2 of the first planetary gear 65A, the second planetary gear 65B, and the third planetary gear 65C.

[0065] (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.

[0066] 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.

[0067] (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 the first teeth T1 of the first planetary gear 65A, the second planetary gear 65B, and the third planetary gear 65C. For ease of viewing, the carrier 64 illustrated in Fig. 1 is omitted in Fig. 2.

[0068] (Career) 6, the carrier 64 is formed, for example, by molding plastic, and includes a pair of disks, each having a hole 64A at the center through which the shaft 42 passes. Three masts 64B and three partition walls 64C extending upward 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. The three first planetary gears 65A, second planetary gears 65B, and third planetary gears 65C are supported by the carrier 64 so as to be freely rotatable.

[0069] (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.

[0070] (Planetary gear) As shown in FIG. 2, the first planetary gear 65A, the second planetary gear 65B, and the third planetary gear 65C each have 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] As shown in Fig. 3, each of the first teeth T1 is symmetrical about a first center line A1 in a plan view. As shown in Fig. 6, the first center line A1 is an imaginary line that extends in the radial direction and passes through the central axis V of each of the first planetary gear 65A, the second planetary gear 65B, and the third planetary gear 65C and the center in the circumferential direction on the first pitch circle C1 of the first tooth T1.

[0072] As shown in Fig. 4, each of the second teeth T2 is symmetrical about the second center line A2 in a plan view. As shown in Fig. 6, the second center line A2 is an imaginary line that extends in the radial direction and passes through the central axis V of rotation of each of the first planetary gear 65A, the second planetary gear 65B, and the third planetary gear 65C and the center in the circumferential direction on the second pitch circle C2 of the second tooth T2.

[0073] 5, the first planetary gear 65A, the second planetary gear 65B, and the third planetary gear 65C are cylindrical members. A hole 65H is formed in the center of the first planetary gear 65A, the second planetary gear 65B, and the third planetary gear 65C, and the hole 65H is rotatably fitted to the mast 64B of the carrier 64. A first tooth T1 and a second tooth T2 are provided on the outer periphery of the first planetary gear 65A, the second planetary gear 65B, and the third planetary gear 65C as a gear portion.

[0074] 6, a single washer-like plate having a plate hole 64A, similar to the plate 64D on the lower surface side, is placed on the upper surface of the carrier 64 on which the first planetary gear 65A, the second planetary gear 65B, and the third planetary gear 65C are fitted to the respective masts 64B. In addition, the convex portions at the tops of the masts 64B and the bulkhead 64C are press-fitted into the plate holes, whereby the first planetary gear 65A, the second planetary gear 65B, and the third planetary gear 65C are fixed to the carrier 64 so as to be freely rotatable.

[0075] In this embodiment, the first tooth T1 and the second tooth T2 are integrally formed in a single planetary gear using the same material, for example, a metal material. Note that in the present disclosure, the first tooth T1 and the second tooth T2 may be separately manufactured and then integrated with each other to form a single planetary gear.

[0076] 5 and 6, in this embodiment, in the three planetary gears, the first planetary gear 65A, the second planetary gear 65B, and the third planetary gear 65C, the diameter of the first pitch circle C1 of the first tooth T1 is the same as the diameter of the second pitch circle C2 of the second tooth T2. In addition, the number of teeth of the first tooth T1 is the same as the number of teeth of the second tooth T2. Therefore, the pitch width P of the first planetary gear 65A, the pitch width P of the second planetary gear 65B, and the pitch width P of the third planetary gear 65C are the same.

[0077] However, in this embodiment, a phase difference is formed between the first center line A1 and the second center line A2 of each of the first planetary gear 65A, the second planetary gear 65B, and the third planetary gear 65C. That is, a preset phase difference is formed between the first tooth T1 and the second tooth T2. Furthermore, the difference between the phase difference of one planetary gear and the phase difference of the other planetary gear among the first planetary gear 65A, the second planetary gear 65B, and the third planetary gear 65C that are adjacent in the circumferential direction is (1 / 3) (the pitch width P of the second tooth T2).

[0078] Specifically, the first planetary gear 65A has a phase difference of 0 (zero). A first phase difference D1 is formed in the second planetary gear 65B, and a second phase difference D2 is formed in the third planetary gear 65C. The first phase difference D1 is (1 / 3)·(the pitch width P of the second teeth T2). The second phase difference D2 is (2 / 3)·(the pitch width P of the second teeth T2).

[0079] In other words, in the second planetary gear 65B and the third planetary gear 65C, the portions in which the tooth tips are oriented in different directions are provided in two stages in the up-down direction in Fig. 5. In addition, in this disclosure, the difference between the phase difference of one planetary gear and the phase difference of the other planetary gear among the planetary gears adjacent in the circumferential direction means the value obtained by subtracting the value in which the phase difference is smaller than the value in which the phase difference is larger than the other planetary gear from the value in which the phase difference is larger than the other planetary gear among the two planetary gears adjacent in the circumferential direction.

[0080] In this embodiment, the number n of planetary gears is 3 as an example, but the value of n is not limited to this in the present disclosure. The present disclosure is also applicable to cases where the value of n is any natural number equal to or greater than 2. In the n planetary gears, the differences between the first planetary gear 65A, the second planetary gear 65B, and the third planetary gear 65C adjacent to each other in the circumferential direction are set to (1 / n)·(pitch width P of the second tooth T2).

[0081] Regarding the phase difference, in the present embodiment, the phase difference of the first planetary gear 65A is set to 0 (zero), the first phase difference D1 of the second planetary gear 65B is set to (1 / 3) · (the pitch width P of the second teeth T2), and the second phase difference D2 of the third planetary gear 65C is set to (2 / 3) · (the pitch width P of the second teeth T2). However, in the present disclosure, the settings of the phase differences are not limited to this and can be changed as appropriate.

[0082] For example, when the number of planetary gears is three, the phase difference of the first planetary gear 65A may be set to (1 / 6) · (pitch width P of the second tooth T2), the phase difference of the second planetary gear 65B may be set to (3 / 6) · (pitch width P of the second tooth T2), and the phase difference of the third planetary gear 65C may be set to (5 / 6) · (pitch width P of the second tooth T2). The respective differences between the first planetary gear 65A, the second planetary gear 65B, and the third planetary gear 65C that are adjacent in the circumferential direction are (1 / 3) · (pitch width P of the second tooth T2).

[0083] (Action and effect) In the motor-operated valve 1 according to this embodiment, the diameter of the first pitch circle C1 of the first tooth T1 and the diameter of the second pitch circle C2 of the second tooth T2 are the same in the three first planetary gears 65A, the second planetary gear 65B, and the third planetary gear 65C. The number of teeth of the first tooth T1 is the same as the number of teeth of the second tooth T2. A preset phase difference is formed between the first tooth T1 and the second tooth T2 of each of the second planetary gears 65B and the third planetary gear 65C. The difference between the phase difference of one planetary gear and the phase difference of the other planetary gear among the first planetary gear 65A, the second planetary gear 65B, and the third planetary gear 65C adjacent in the circumferential direction is (1 / n)·(pitch width P of the second tooth T2).

[0084] Here, when the difference in the number of teeth between the fixed gear 62 and the output gear 66 is 1, at the meshing position of the second tooth T2, the phase difference between the second center line A2 of the second tooth T2 and the center line of the groove of the output gear 66 increases by (1 / 3) (pitch width of the output gear) in the order in which the first planetary gear 65A, the second planetary gear 65B, and the third planetary gear 65C are arranged along the circumferential direction.

[0085] In this embodiment, the sum of the phase differences between the second center line A2 of the second teeth T2 of the first planetary gear 65A, the second planetary gear 65B, and the third planetary gear 65C and the center line of the groove of the output gear 66 is formed in advance so as to correspond to a distance of one pitch width of the output gear 66. Therefore, it is possible to set the minimum value of the difference in the number of teeth between the number of teeth of the fixed gear 62 meshing with the first teeth T1 and the number of teeth of the output gear 66 meshing with the second teeth T2 to one. Therefore, it is possible to make the difference in the number of teeth smaller than n, and as a result, it is possible to increase the reduction ratio of the planetary gear type reduction mechanism. Similarly, it is possible to increase the reduction ratio of the motor-operated valve 1 according to this embodiment.

[0086] As can be seen from the above formula (1) or (2), apart from the means for reducing the difference in the number of teeth between the fixed gear 62 and the output gear 66, a technique for increasing the reduction ratio by increasing the number of teeth of one of the fixed gear 62 and the output gear 66 is also conceivable. Here, in the case of a relatively small motor-operated valve, the external dimensions of the fixed gear 62 and the output gear 66 are often limited. For this reason, if an attempt is made to increase the number of teeth, it is necessary to reduce the size of each tooth.

[0087] However, if the size of each tooth is reduced, it becomes difficult to ensure the durability of the teeth. In this embodiment, in addition to being able to increase the reduction ratio, it is advantageous in that the motor-operated valve can be made smaller without increasing the number of teeth of the fixed gear 62 and the output gear 66.

[0088] 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.

[0089] 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.

[0090] 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. <Other embodiments>

[0091] 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]

[0092] 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 64A hole 64B Mast 64C Bulkhead 64D Plate 65A First Planetary Gear 65B Second planetary gear 65C 3rd 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 D1 First phase difference D2 Second phase difference P Pitch width R1 Input area R2 output area 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: n planetary gears (n: a natural number of 2 or more) each including first teeth to which an input rotation of the electric motor is input and second teeth provided corresponding to 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; a valve body portion that controls the opening degree of the valve by the output rotation, In the n planetary gears, a diameter of a first pitch circle of the first tooth is equal to a diameter of a second pitch circle of the second tooth; The number of teeth of the first teeth is equal to the number of teeth of the second teeth, a preset phase difference is formed between the first tooth and the second tooth of one of the planetary gears, and a difference between the phase difference of one of the planetary gears adjacent to each other in the circumferential direction and the phase difference of the other planetary gear is (1 / n) · (pitch width of the second tooth); Electric valve.

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 planetary gear set includes n planetary gears (n: a natural number of 2 or more) each 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 an output gear that meshes with the second tooth and outputs an output rotation that is a reduced-speed version of the input rotation, In the n planetary gears, a diameter of a first pitch circle of the first tooth is equal to a diameter of a second pitch circle of the second tooth; The number of teeth of the first teeth is equal to the number of teeth of the second teeth, a preset phase difference is formed between the first tooth and the second tooth of one of the planetary gears, and a difference between the phase difference of one of the planetary gears adjacent to each other in the circumferential direction and the phase difference of the other planetary gear is (1 / n) · (pitch width of the second tooth); Planetary gear reduction mechanism.

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