JP2008014485A - Motor driven valve - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a small and inexpensive motor driven valve having a high-resolution valve opening angle without using an expensive planetary gear reduction mechanism. <P>SOLUTION: The motor driven valve 1 for controlling the flow amount of refrigerant in an air-conditioner comprises a spur gear type reduction ring train mechanism 50 formed with a plurality of spur gears 54-58 combined for reducing the speed of rotation of an electric motor 30 to be lower to convert the opening/closing operation of the valve. D and K satisfy a relationship of D=α×m, α=20 to 100, K=m/β, and β=8 to 20, where m is the module of the spur gears 54-58, 1/K is a reduction ratio, and D is the diameter of a circle representing the maximum outside dimension of the spur gear type reduction ring train mechanism in the radial direction of the gears. So, the spur gears have a good dimensional balance, thus providing the small and inexpensive motor driven valve 1 with high resolution and a great reduction ratio. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an electric valve that controls the flow rate of refrigerant in an air conditioner, and more particularly to a flat gear that combines a plurality of spur gears in order to decelerate rotation of an electric motor to low-speed rotation in order to convert the rotation of the electric motor into valve opening / closing operation. The present invention relates to an electric valve provided with a gear-type reduction gear train mechanism.

The following two types are widely known as motor-operated valves that control the flow rate of the refrigerant of the air conditioner and convert the rotation of the electric motor into the opening / closing operation of the valve. The first type is such that the rotation of the rotor is directly transmitted to the screw mechanism to open and close the valve, and is disclosed in Patent Document 1 and Patent Document 2, for example. The second type is one in which the rotation of the rotor is reduced by a reduction device and transmitted to the screw mechanism, and is disclosed in, for example, Patent Document 3 and Patent Document 4.
JP 2000-356278 A Japanese Patent Laid-Open No. 2004-197800 JP 2002-84732 A JP 2003-232465 A

Although the first type motor-operated valve can be configured relatively compactly, it has the disadvantages that it is limited to a low load application and that it is difficult to finely set the valve opening per drive pulse. is doing.
The electric valve of the second type can be used even when the load is large, and the valve opening per driving pulse can be set finely. To make it compact, for example, a planetary gear type reduction mechanism is used. Will be adopted. However, the planetary gear type reduction mechanism is required to have strict manufacturing accuracy, and has a problem that the structure becomes complicated and the manufacturing cost increases.

  An object of the present invention is to provide a small and inexpensive electric valve that can have a high resolution valve opening without using an expensive planetary gear reduction mechanism.

An electric valve according to the present invention is an electric valve that controls the flow rate of refrigerant in an air conditioner, and a plurality of spur gears are provided to reduce the rotation of the electric motor to a low-speed rotation in order to convert the rotation of the electric motor into an opening / closing operation of the valve. A spur gear reduction gear train mechanism is provided in combination, the spur gear module used in the spur gear reduction gear train mechanism is m, the reduction ratio is 1 / K, and the gear radial direction of the spur gear reduction gear train mechanism When the diameter of a circle representing the maximum outer dimension of the above is D, D and K satisfy the following relationship.
D = α · m α = 20-100
K = m / β β = 8-20

  According to this motor operated valve, the spur gear module used in the spur gear reduction gear train mechanism, the reduction ratio, and the diameter of the circle representing the maximum outer diameter in the gear radial direction are determined within the above range. It is possible to obtain a motor-operated valve having a good balance of dimensions of each spur gear of the gear type reduction gear train mechanism, small size and low cost, high resolution, and a large reduction ratio.

  In the motor-operated valve, the spur gear type reduction gear train mechanism may be provided with a plurality of speed reduction stages composed of two spur gears meshing with each other. According to such a configuration, when the output rotation of the electric motor is input to the spur gear reduction gear train mechanism, it is decelerated at a very high reduction ratio by a plurality of reduction gear stages, and the valve opening degree is controlled with high resolution. can do.

  In the electric valve, the module m of the spur gear of the spur gear type reduction gear train mechanism is 0.2 to 0.4, the diameter D of the circle representing the maximum outer dimension is 40 mm or less, and the reduction ratio 1 / K can be 1/30 to 1/100. By selecting these numerical ranges, it is possible to obtain a motor-operated valve having a large reduction ratio while being sufficiently small in the axial direction and the radial direction without being difficult to manufacture.

  More specifically, in the motor operated valve, the spur gear type reduction gear train mechanism is housed in a gear box, and the rotational output from the spur gear type reduction gear train mechanism is converted into an output displacement in the screw shaft direction. A screw mechanism that is attached to the gear box, and the electric motor is rotatably supported on the outside of the gear box, and is rotatably supported on the outside of the gear box. A permanent magnet type rotor assembly that is driven to rotate and inputs the rotation to the spur gear type reduction gear train mechanism, and a valve body connected to the screw mechanism portion is provided outside the gear box. The valve body is arranged to open and close a valve chamber, a valve seat formed on a part of a wall surface of the valve chamber, and an opening formed in the valve seat in contact with and away from the valve seat And receiving the output displacement of the screw mechanism portion, the valve body May comprise a valve stem contacting and separating with respect to the valve seat, and a bellows refrigerant mounted over said valve body with the valve stem is prevented from entering into the gear box.

  The screw used for the screw mechanism portion may have a screw pitch of 0.5 to 1.5 mm and a screw size in the range of M3 to M7. When the rotation of the motor is greatly decelerated by the spur gear type reduction gear train mechanism, the rotation output with a large torque correspondingly acts on the screw, but the screw of the screw mechanism section is in the above numerical range. By adopting the screw, the valve element can be reliably operated while being small.

  With the motor-driven valve according to the present invention configured as described above, the rotation of the electric motor is transmitted with a large reduction ratio by the deceleration action of the spur gear type reduction gear train mechanism, and a large torque is obtained at the decelerated output. be able to. Therefore, a powerful valve driving force can be exhibited in the screw mechanism portion that converts the output rotation of the spur gear type reduction gear train mechanism into the opening / closing operation of the valve. In addition, since a greatly decelerated rotation is given to the screw mechanism, the moving distance of the valve body relative to the valve seat, that is, the opening degree of the opening formed in the valve seat can be controlled with high accuracy, and the resolution of the valve opening degree is high. The flow rate passing through the motor-operated valve can be controlled with high accuracy. Furthermore, the specifications of each spur gear are set in a well-balanced manner without any severe design and manufacturing restrictions imposed on each spur gear of the spur gear type reduction gear train mechanism. Therefore, it is possible to reduce the size as much as possible while adopting the spur gear type reduction gear train mechanism. The motor-operated valve according to the present invention has a simple structure and is excellent in mass productivity, and can be manufactured at low cost.

  FIG. 1 is a longitudinal sectional view of a main part excluding a valve body of an electric valve (hereinafter simply referred to as “electric valve”) provided with a spur gear reduction gear train mechanism according to the present invention. Note that hatching is omitted for some elements. FIG. 2 is a cross-sectional view showing details of a valve main body, a screw bearing, a screw shaft, and a ball combined with the main part of the electric valve shown in FIG.

  As shown in FIG. 1, the motor-operated valve denoted by reference numeral 1 as a whole has, as a basic structure, a drive unit 2 including an electric motor that operates with an excitation function and includes a stator and a rotor, and a rotational driving force by the drive unit 2. The gear speed reducer unit 3 including a spur gear type reduction gear train mechanism that receives the input and performs gear reduction to output the reduced rotation, and the reduced speed rotation from the gear speed reducer unit 3 is converted into a displacement in the screw axis direction by a screw action. And a screw mechanism portion 4 for outputting the output. The motor-operated valve 1 is used as a valve that is completed by connecting the valve main body portion to the output portion of the screw mechanism portion 4, but FIG. 1 does not show the valve main body portion to be connected. The displacement output in the screw axis direction of the screw mechanism portion 4 is transmitted to the valve body portion indicated by reference numeral 5 in FIG.

  In the motor-operated valve 1, the drive unit 2 has an electric motor having a cylindrical motor excitation device 31 that constitutes a stator, and a permanent magnet type rotor assembly 32 that is disposed inside the motor excitation device 31 and is driven to rotate. A motor 30 is provided. The electric motor 30 is a stepping motor. The motor exciter 31 includes a coil 33 wound around a bobbin 34 provided inside, and a stator 35 excited by energization of the coil 33, and the coil 33 includes an electric circuit 36, a lead 37, and a lead wire 7. It is connected to an external power supply via the power supply and receives power. The rotor assembly 32 includes an output gear 40 at the lower end portion of a support shaft 39 that transmits the output rotation as an output portion.

  The drive unit 2 is disposed above the gear reducer unit 3 as a whole, and the support shaft 39 extends into the gear reducer unit 3 to transmit the rotation of the output gear 40 to the gear reducer unit 3. The drive unit 2 and the gear reducer unit 3 are covered with a cover 41 that is an airtight container. The cover 41 is a top-shaped cylindrical container made of a metal material, and its lower portion 41a covers a gear box 43 provided in the gear reducer unit 3 and extends integrally above the lower portion 41a. The upper portion 41b accommodates the electric motor 30 of the drive unit 2. In order to make the drawing easier to see, each spur gear of the gear reduction unit 3 is shown in a laterally expanded manner, and thus the cover 41 is drawn in a multi-stage cylindrical shape. Is located below the electric motor 30 and the cover 41 is a linear cylinder. When the cover 41 is mounted on the motor excitation device 31, the motor excitation device 31 is pressed and fixed onto the gear box 43 by a fixture 42 formed by a leaf spring. The cover 41 is fixed integrally with a rubber covering portion 34 that covers the bottom plate 431 of the gear box 43 on the bottom side. The lower end peripheral portion of the lower portion 41a and the peripheral portion of the cover portion 34 are fixed by a caulking portion 41d, and the inside of the cover 41 is kept sealed from the outside.

  The gear reduction unit 3 of the motor-operated valve 1 includes a spur gear type reduction gear train mechanism (hereinafter abbreviated as “reduction gear train mechanism”) 50 that reduces the rotation of the rotor assembly 32. The reduction gear train mechanism 50 includes longitudinal rotation shafts 51, 52, and 53 that are disposed in parallel to and spaced from the support shaft 39 of the drive unit 2, and for deceleration provided on the longitudinal rotation shafts 51 to 53, respectively. Large-diameter gears 54, 55, and 56 and small-diameter gears 57 and 58. The large diameter gear 54 meshes with the output gear 40, the small diameter gear 57 integral with the large diameter gear 54 meshes with the large diameter gear 55, and the small diameter gear 58 integral with the large diameter gear 55 meshes with the large diameter gear 56. By these gears, the rotation of the rotor assembly 32 is greatly decelerated and transmitted to the vertical rotation shaft 53 integral with the gear 56 of the final stage.

  In the screw mechanism portion 4 connected to the vertical rotation shaft 53 that is the output gear shaft of the reduction gear train mechanism 50, the rotation output from the vertical rotation shaft 53 is a flat driver portion 63 formed at the lower end of the vertical rotation shaft 53. Is transmitted to the screw shaft 62 via. In the upper part of the screw shaft 62, a slit 64 into which the flat driver portion 63 is inserted is formed. The screw shaft 62 is screwed into a female screw 61 formed on the inner surface of the cylindrical bearing 60. A recess 66 is formed in the lower portion of the screw shaft 62, and a ball 67 is fixed to the recess 66. A nut member 65 fixed to a valve body 5 described later is supported at the lower end of the bearing 60. The bearing 60 is rotatably assembled with the nut member 65. When the rotation of the rotor assembly 32 is transmitted to the longitudinal rotation shaft 53 via the reduction gear train mechanism 50, the screw mechanism portion 4 of the motor-operated valve 1 is described later via the screw shaft 62 and the ball 66. Convert to linear motion to open and close the valve.

  Next, details of the valve body 5 of the motor-operated valve 1 will be described. FIG. 2 is a cross-sectional view showing details of the valve main body 70, the valve stem 80, and the like provided in the valve main body 5. The valve main body 70 has a valve chamber 72 formed in the lower part inside, and a valve seat 77 is formed as a part of the wall surface of the valve chamber 72. The valve body 70 is formed with an orifice 74 that extends downward from the bottom and communicates with the valve chamber 72. In addition, a pipe 78 a that communicates with the side surface of the valve chamber 72 and a pipe 78 b that communicates with the orifice 74 are airtightly attached to the valve body 70 in order to allow the refrigerant to flow in and out. The outer peripheral portion of the upper end portion of the valve main body 70 is screw-engaged with the inner peripheral portion of the nut member 65 to prevent moisture and the like from entering the valve main body 70. Further, the valve body 70 is formed with a chamber 76 that communicates with the upper portion of the valve chamber 72 and into which the refrigerant is introduced.

  In the valve chamber 72, a valve body 90 that opens and closes an opening formed in the valve seat 77 by being in contact with and away from the valve seat 77 is disposed. In order to move the valve body 90, a valve rod 80 linked to the screw shaft 62 of the screw mechanism 4 is connected to the valve body 90. An upper end portion 82 of a bellows 81 disposed outside the valve stem 80 is fixed to the valve main body 70 via a ring member 83 by caulking. Regarding the fixing of the ring member 83 to the valve body 70, airtightness is maintained by soldering in addition to caulking.

  A lower end 84 of the bellows 81 is fixed to the valve stem 80. The bellows 81 prevents the refrigerant introduced into the chamber 76 of the valve body 70 from entering the gear box 43. A ball receiving member 85 for the ball 67 is inserted and fixed at the upper end of the valve stem 80. As shown in FIG. 1, the screw shaft 62 contacts the upper portion of the ball 67, and axial thrust is transmitted to the valve stem 80 side by the screw mechanism 4.

  The rotor assembly 32 provided inside the cover 41 rotates by supplying a drive signal to the coil 33 of the motor excitation device 31.

  In the valve body 5, the valve body 90 is moved toward and away from the valve seat 77 in response to the displacement output in the screw shaft direction, and the valve opening is changed by the operation. That is, in the valve main body 5, when the screw shaft 62 rotates in the bearing 60, the screw shaft 62 is converted into axial movement, and the axial movement amount of the screw shaft 62 includes the ball 67 and the ball receiving member 85. The valve body 90 attached to the tip of the valve stem 80 moves linearly in the vertical direction. Thereby, the flow passage area between the valve body 90 and the orifice 74 is controlled, and the flow rate of the refrigerant is adjusted. At this time, the bellows 81 mounted across the valve stem 80 and the valve body 70 prevents the refrigerant introduced into the chamber 76 communicating with the valve chamber 72 from entering the gear box 43.

  In the reduction gear train mechanism 50, rotation from the output gear 40 of the rotor assembly 32 is input. The output gear 40 is a small-diameter gear, and the first reduction gear stage is constituted by the large-diameter gear 54 that meshes with the output gear 40 and is supported by the vertical rotation shaft 51. The second reduction stage is constituted by the small-diameter gear 57 integral with the large-diameter gear 54 and the large-diameter gear 55 supported by the adjacent vertical rotation shaft 52. Similarly, a third reduction gear stage is constituted by a small-diameter gear 58 integral with the large-diameter gear 55 and a large-diameter gear 56 supported by the adjacent vertical rotation shaft (output gear shaft) 53. A rotation shaft (output gear shaft) 53 is an output shaft of the reduction gear train mechanism 50. Therefore, in the gear reducer unit 3, the output rotation of the electric motor 30 (rotation of the rotor assembly 32) is reduced at a large reduction ratio of about 50 to 1, for example, by a plurality of reduction stages connected in the gear radial direction. Is transmitted to the screw shaft 62. As a result, the screw shaft 62 can be rotated at a minute rotational speed, and the valve opening degree control with high resolution is achieved.

  Examples of the motor-operated valve according to the present invention include the following. In the motor-operated valve 1, the gear module m that determines the size of the spur gear teeth used in the reduction gear train mechanism 50 is preferably 0.2 to 0.4. If the gear module m is made smaller than this range, the tooth size of the spur gear becomes too small, making it difficult to manufacture, and increasing the length in the gear shaft direction to withstand the magnitude of the transmission torque. A necessity arises and the gear axial direction length of the gear reduction gear part 3 becomes long. On the contrary, if the gear module m is made larger than the above range, it becomes easy to manufacture, but the gear diameter is increased, and a circle representing the maximum outer dimension in the gear radial direction of the reduction gear train mechanism 50 (shown by a broken line in FIG. 4). The diameter of the circle), that is, the size of the motor-operated valve 1 is also increased. This circle is the smallest circle having a diameter in the radial direction of the spur gear type reduction gear train mechanism 50 and including all the spur gears 54 to 58, and passes through the tooth tips of some or all of the spur gears. It is. The reduction gear train mechanism 50 can obtain a large value such that the reduction ratio is 30 to 100 while the maximum outer dimension is small such that the diameter is 15 to 40 mm. Further, the screw shaft 62 of the screw mechanism 4 can be a small triangular screw of M3 to M7 having a screw pitch of 0.5 to 1.5 mm (or a trapezoidal screw or a square screw is also possible).

  As an example, the number of reduction stages is 3 or 4, the module m is 0.2, 0.3, 0.4, and the diameter of the circle representing the maximum outer dimension in the gear radial direction of the reduction gear train mechanism is 15 to 40 mm. 3 shows that a combination with a reduction ratio of 30 to 100 is obtained.

Sectional drawing which shows the electric motor and deceleration mechanism of the electrically operated valve by this invention. Sectional drawing which shows the detail of the valve main body of the motor operated valve by this invention. The graph which shows the relationship between the reduction ratio and the diameter of the circle | round | yen showing the maximum external dimension of the gear radial direction of a reduction gear train mechanism. Explanatory drawing which shows the circle | round | yen showing the maximum external dimension of the gear radial direction of a spur gear type reduction mechanism.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Electric valve 2 Drive part 3 Gear speed reducer part 4 Screw mechanism part 4a Output part 5 Valve body part 30 Electric motor 31 Motor exciter 32 Rotor assembly 33 Coil 34 Resin mold 35 Stator 36 Electric circuit 37 Lead 38 Power supply 39 Output shaft 40 output gear 41 cover 41a low stage part 41b high stage part 42 fitting 43 gear box 50 spur gear type reduction gear train mechanism (reduction gear train mechanism)
51, 52, 53 Vertical rotation shaft (or rotation support shaft) (53: output gear shaft)
54, 55, 56 Large diameter gears 57, 58 Small diameter gear 60 Bearing 61 Female screw 62 Screw shaft 63 Flat driver 64 Slit 65 Nut member 66 Recessed 67 Ball 70 Valve body 72 Valve chamber 74 Orifice 76 Chamber 77 Valve seat 78a, 78b Piping 79 Receiving portion 80 Valve rod 81 Bellows 82 Upper end portion 83 Ring member 84 Lower end portion 85 Ball receiving member 90 Valve body

Claims (5)

An electric valve that controls the flow rate of the refrigerant of the air conditioner,
In order to reduce the rotation of the electric motor to low-speed rotation in order to convert the rotation of the valve into a valve opening / closing operation, a spur gear type reduction gear train mechanism comprising a combination of a plurality of spur gears is provided.
The spur gear module used in the spur gear reduction gear train mechanism is m, the reduction ratio is 1 / K, and the diameter of the circle representing the maximum outer dimension in the gear radial direction of the spur gear reduction gear train mechanism is D. A motor-operated valve in which D and K satisfy the following relationship:
D = α · m α = 20-100
K = m / β β = 8-20   2. The motor-operated valve according to claim 1, wherein the spur gear type reduction gear train mechanism includes a plurality of speed reduction stages including two spur gears meshing with each other.   The module m of the spur gear of the spur gear type reduction gear train mechanism is 0.2 to 0.4, the diameter D of the circle representing the dimension of the maximum outer shape is 40 mm or less, and the reduction ratio 1 / K is The motor operated valve according to claim 1, which is 1/30 to 1/100. The spur gear type reduction gear train mechanism is housed in a gear box, and a screw mechanism unit that converts rotational output from the spur gear type reduction gear train mechanism into output displacement in the screw shaft direction is attached to the gear box. And
The electric motor includes a motor exciter disposed outside the gear box, and is rotatably supported by the outside of the gear box and is rotationally driven by the motor exciter and rotates the spur gear reduction wheel. A permanent magnet type rotor assembly for inputting to the row mechanism,
A valve body connected to the screw mechanism is disposed outside the gear box, and the valve body includes a valve chamber, a valve seat formed on a part of a wall surface of the valve chamber, and the valve seat. A valve body that opens and closes an opening formed in the valve seat by contact with and away from the valve, a valve rod that receives and outputs an output displacement of the screw mechanism portion, and a valve rod that contacts and separates the valve seat; The motor-operated valve of any one of Claims 1-3 provided with the bellows with which it mounts | wears over the said valve main body, and blocks | prevents that a refrigerant | coolant penetrate | invades in the said gear box.   The motor-operated valve according to claim 4, wherein the screw used in the screw mechanism section has a screw pitch of 0.5 to 1.5 mm and a screw size in a range of M3 to M7.

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