JP2017198260A - Planetary gear-type reduction gear and motor-driven valve including the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a planetary gear-type reduction gear capable of suppressing degradation of transmission efficiency of the reduction gear and durability of a gear, and a motor-driven valve including the same.SOLUTION: A planetary gear-type reduction gear includes a sun gear supported by a shaft, a fixed gear fixed concentrically with the sun gear, a planetary gear simultaneously engaged with both of the sun gear and the fixed gear, a carrier composed of a bottom plate portion rotated on a center axis of the shaft and a spindle rotatably supporting the planetary gear, and an output gear engaged with the planetary gear. An auxiliary gear engaged with the planetary gear while concentrically rotated with the sun gear, is further disposed between the sun gear and the bottom plate portion of the carrier.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a planetary gear type reduction device and an electric valve equipped with the planetary gear type reduction device, and more particularly to a planetary gear type reduction device capable of improving durability and an electric valve equipped with the planetary gear type reduction device.

For example, in order to control the flow rate of refrigerant in an air conditioner, a so-called electric valve that opens and closes a valve via an electric motor is widely used.
As such an electric valve, there is known an electric valve provided with a reduction gear that reduces the rotation of the rotor of the electric motor with a reduction gear and transmits it to a screw mechanism (see Patent Document 1).

In the electric valve described in Patent Document 1, a planetary gear type reduction device is used as a reduction device.
Such a planetary gear speed reduction device includes a sun gear that is rotationally driven by the rotation of the rotor of the electric motor, a fixed gear that is fixed to the main body of the electric motor so as to face the sun gear, and these sun gears. And a plurality of planetary gears that mesh with these gears and an output gear that transmits rotation from the plurality of planetary gears.

The plurality of planetary gears are attached to a carrier on which a support shaft that rotatably supports the planetary gears is erected on a bottom plate, and these planetary gears are separated from the fixed gears in an axial direction with the output gears. By engaging, the carrier is configured to rotate around the rotation axis of the sun gear.
When the sun gear rotates, the planetary gear that meshes with the fixed gear rotates while being supported by the carrier, and revolves around the sun gear, so that the output gear is decelerated according to the number of teeth difference from the fixed gear. Rotation is output.

FIG. 3 shows an outline of a main part of a planetary gear type speed reducer applied to a conventional motor-operated valve described in Patent Document 1, for example. FIG. 3 (a) shows the rotation at the upper part of the sun gear. It is a principal part enlarged view of a cross section perpendicular | vertical to an axis | shaft, FIG.3 (b) is sectional drawing in the BB surface of Fig.3 (a).
As shown in FIG. 3A, the sun gear 2 rotatably supported by the shaft 1 rotates in the direction of the arrow d1 by the rotation of the rotor of the electric motor (not shown).

Between the fixed gear (internal gear) 3 fixed facing the sun gear 2, planetary gears 5 rotatably supported by a plurality of support shafts 4 erected on a carrier (not shown) It arrange | positions so that both the gear 2 and the fixed gear 3 may mesh | engage.
Further, an annular plate 6 having a plurality of through holes 6a into which the tops of the respective support shafts 4 are inserted is attached to the upper part of the planetary gear 5, and the annular plate 6 rotates integrally with the carrier. At the same time, the planetary gear 5 is prevented from jumping upward.

Japanese Patent No. 5111240

In the planetary gear type reduction gear as described above, when the sun gear 2 rotates, the planetary gear 5 that meshes with the sun gear 2 rotates in the direction of the arrow d2.
At this time, since the planetary gear 5 is also meshed with the fixed gear 3, the planetary gear 5 revolves around the sun gear 2 along with its rotation. That is, since the planetary gear 5 receives a reaction force from the fixed gear 3, the support shaft 4 that supports the planetary gear 5 also receives a force in the direction of the arrow d3 shown in FIG.

When the support shaft 4 erected from the carrier receives a force in the direction of the arrow d3, the support shaft 4 has a cantilever structure. Therefore, as shown in FIG. O2 is tilted from the original position O1 by an angle θ.
On the other hand, since the support shaft 4 rotatably supports the planetary gear 5, a manufacturing clearance (gap e) exists between the support shaft 4 and the planetary gear 5.

When the inclination angle θ and the gap e are generated as described above, the planetary gear 5 comes into contact with the sun gear 2 or the fixed gear 3 with the rotation axis inclined.
Then, if the planetary gear 5 and the sun gear 2 or the fixed gear 3 are inclined, there is a concern that the interference of the tooth bottom occurs between these gears and the transmission efficiency of the reduction gear decreases.
Further, when the planetary gear 5 is inclined, there is a concern that the meshing between the sun gear 2, the fixed gear 3, and the planetary gear 5 is biased, and the gear is unevenly worn, thereby reducing the durability of the gear. .

  SUMMARY OF THE INVENTION An object of the present invention is to provide a planetary gear type reduction device that suppresses a reduction in transmission efficiency and gear durability of the reduction device, and an electric valve equipped with the planetary gear type reduction device.

  In order to achieve the above object, a planetary gear reduction device according to the present invention includes a sun gear supported by a shaft, a fixed gear concentrically fixed to the sun gear, and both the sun gear and the fixed gear. A planetary gear that meshes simultaneously with the carrier; a carrier that includes a bottom plate that rotates about the central axis of the shaft and a support shaft that rotatably supports the planetary gear; and an output gear that meshes with the planetary gear. An auxiliary gear that rotates concentrically with the sun gear and meshes with the planetary gear is further provided between the gear and the bottom plate portion of the carrier.

In the planetary gear type reduction gear according to a typical example of the present invention, the sun gear and the fixed gear have tooth widths such that the meshing widths of the planetary gear are substantially the same.
The auxiliary gear may be different in gear shape from the sun gear. As such an example, for example, the auxiliary gear and the sun gear have the same module and pressure angle, and the tooth thickness of the auxiliary gear is set to be larger than the tooth thickness of the sun gear. .

In the planetary gear type reduction gear according to a typical example of the present invention, the auxiliary gear has a backlash when the auxiliary gear and the planetary gear mesh with each other, and the sun gear and the planetary gear mesh with each other. It is formed in a shape that is smaller than the backlash. Furthermore, the auxiliary gear may be formed of a resin material.
The planetary gear type speed reducer according to the present invention can be applied to an electric valve.

  According to the planetary gear type speed reducer according to the present invention, by providing the above-described configuration, the inclination of the planetary gear is alleviated, and as a result, it is possible to suppress a reduction in transmission efficiency of the speed reducer and gear durability. .

1 is a longitudinal sectional view showing the entire structure of a planetary gear type motor-operated valve to which a planetary gear type reduction device according to an embodiment of the present invention is applied. It is a figure which shows the outline of the planetary gear-type speed reducer shown by FIG. 1, Comprising: FIG. 2 (a) is a fragmentary sectional view, FIG.2 (b) is AA sectional drawing of Fig.2 (a). is there. FIG. 3A shows an outline of the main part of a planetary gear type reduction gear applied to a conventional motor-operated valve, and FIG. 3A is an enlarged view of the main part of a cross section perpendicular to the rotation axis at the top of the sun gear; FIG.3 (b) is sectional drawing in the BB surface of Fig.3 (a).

FIG. 1 is a longitudinal sectional view showing the entire structure of a planetary gear type motor-operated valve to which a planetary gear type reduction gear according to an embodiment of the present invention is applied.
A planetary gear type motor-operated valve (hereinafter referred to as “motor valve”) 10 shown in FIG. 1 includes a valve main body 20 including a valve chamber 21 therein, a can 30 fixed to the upper end of the valve main body 20, Arranged in such a manner as to surround the outside of the can 30, the valve body driving mechanism 40 attached to the upper end of the valve body 20 inside, the planetary gear type reduction device 100 coupled to the valve body driving mechanism 40 inside the can 30. Motor excitation device (stator device) 50.

The valve body 20 is, for example, a metal member having a bottomed cylindrical shape, and a cylindrical bearing 41 of a valve body driving mechanism 40 described later is fixed to an upper opening end of the valve main body 20 so that the valve chamber 21 is inside. Is formed.
An inflow pipe 26 a communicating with the valve chamber 21 is attached to the side of the valve body 20, and a small hole (orifice) 22 communicating with the valve chamber 21 is formed at the bottom of the valve body 20, An outflow pipe 26b is attached.

Inside the valve chamber 21, a valve body 23 that opens and closes the orifice 22, a spring 25 that biases the valve body 23 upward (in the opening direction of the valve body 23), and a spring provided around the spring 25 A receiving member 24 is disposed.
The valve body 23 is formed with a flange portion 23 a that expands outward at the upper end, and a tapered portion 23 b that is inserted into the orifice 22 at the lower end.

The spring receiving member 24 is a cylindrical member that is disposed outside the valve body 23, and has a flange portion 24a that expands outward at the upper end, and a step portion 24b that is formed in an intermediate region. The vicinity of the lower end has a small diameter and is slidably in contact with the outer peripheral surface of the valve body 23.
A spring 25 is disposed between the step portion 24 b of the spring receiving member 24 and the lower surface of the flange portion 23 a of the valve body 23. With this arrangement, the spring 25 constantly biases the flange portion 23a of the valve body 23 upward.

The can 30 is a thin cylindrical member with a top, and is attached in such a manner as to accommodate the top of the valve body 20 via a receiving member 31 fixed to the outer peripheral surface of the valve body 20.
In addition, a shaft holding member 32 that holds a shaft 33 that serves as a rotating shaft of a planetary gear reduction device 100 described later is fixed above the internal space of the can 30.
The can 30 functions as an airtight container that seals an internal space formed between the upper portion of the valve body 20 and a valve body drive mechanism 40 and a planetary gear speed reducer 100, which will be described later, are provided in the internal space. Accommodate.

The valve body drive mechanism 40 includes a cylindrical bearing 41 having a receiving hole 41a for receiving the output shaft (see reference numeral 131 in FIG. 2) of the planetary gear type reduction gear 100, and the output shaft while being received in the receiving hole 41a. And a ball 43 that contacts one end of the screw shaft 42, and a ball support member 44 that is attached to the top of the valve body 23 and supports the ball 43.
The cylindrical bearing 41 is inserted so as to fit into the opening at the top of the valve main body 20, and is in contact with the stepped portion 20 a inside the valve main body 20 so as to sandwich the flange portion 24 a of the spring receiving member 24 described above. It is fixed.
A female screw is formed at the lower end of the accommodation hole 41 a of the cylindrical bearing 41.

The screw shaft 42 is formed with a male screw threadedly engaged with the female screw on its outer periphery, and a plano-convex portion 42a inserted into a slit formed in the output shaft 131 of the planetary gear type speed reducer 100 at the upper end thereof. Is formed.
When the output shaft 131 of the planetary gear type reduction gear 100 is rotated by the valve body driving mechanism 40 as described above, the screw shaft 42 connected to the output shaft 131 is also rotated, whereby the rotational motion of the screw shaft 42 is reduced. It is converted into a directional movement.
The forward / backward movement of the screw shaft 42 is transmitted to the valve body 23 via the ball 43 and the ball support member 44, and the valve body 23 moves forward / backward in the axial direction.

The motor excitation device 50 is obtained by integrally resin-molding a stator coil 51 in which a conducting wire is wound around a bobbin, and a connector 52 and a lead wire 53 that supply electric power to the stator coil 51. An arrangement 51 surrounds the outer periphery of the can 30, and is detachably attached to the can 30 via an attachment 54.
On the other hand, the planetary gear speed reduction device 100 includes a rotor assembly 110 into which a shaft 33 attached to the internal space of the can 30 is inserted and fixed. In the motor-operated valve 10, the stator coil 51 of the motor excitation device 50 and the planetary gears. The rotor assembly 110 of the gear type reduction gear 100 constitutes a stepping motor as an example of an electric motor.

2A and 2B are diagrams schematically illustrating the planetary gear type speed reducer illustrated in FIG. 1, in which FIG. 2A is a partial cross-sectional view, and FIG. 2B is a cross-sectional view taken along line B- in FIG. It is B sectional drawing.
As shown in FIG. 2, the planetary gear type speed reducer 100 includes a top-cylindrical rotor assembly 110 (see FIG. 1) and an annular internal gear fixedly attached to the valve body 20 via a support member 121. A fixed gear 120, a bottomed cylindrical output gear 130 which is an internal gear having an output shaft 131 rotatably supported by the shaft 33, and the fixed gear 120 and the output gear while the shaft 33 is detachably inserted. And a plurality of planetary gears 150 rotatably supported by the carrier 140.

The rotor assembly 110 shown in FIG. 1 is formed of a resin material such as plastic containing a magnetic material, for example, and includes a cylindrical portion 111 having a peripheral wall and a bottom portion 112 having a sun gear 112a projecting at the center. It is a member formed integrally.
The sun gear 112a has a through hole through which the shaft 33 is inserted at the center, and external teeth that mesh with the planetary gear 150 are formed on the outer peripheral surface.
In addition, the cylinder part 111 and the bottom part 112 may be manufactured and assembled separately, and may be formed by integral molding.

The fixed gear 120 is a ring gear manufactured by molding a resin material such as plastic, for example, and has inner teeth that mesh with the upper portion of the planetary gear 150 on the inner peripheral side.
The fixed gear 120 is fixed to the upper end portion of the valve main body 20 via a cylindrical support member 121.

The output gear 130 is a bottomed cylindrical ring gear manufactured by molding a resin material such as plastic, for example, and the output shaft 131 is press-fitted and fixed in a through hole formed in the center thereof.
Inner teeth that mesh with the planetary gear 150 are formed on the inner wall surface of the output gear 130.

The output shaft 131 has an insertion hole for inserting the shaft 33 on the upper end side, and a slit into which the above-described flat convex portion 42a of the screw shaft 42 is inserted is formed on the lower end side (see FIG. 1).
With these configurations, the rotation of the output shaft 131 fixed to the output gear 130 is transmitted to the screw shaft 42 through the coupling (engagement) between the slit and the plano-convex portion, and the output gear 130 and the screw shaft 42 are connected to each other. Rotate in the same direction.

The carrier 140 is a resin part or a metal part produced by molding a resin material such as plastic, for example, and includes a bottom plate part 141 having a through-hole into which the shaft 33 is inserted, and the bottom plate part 141. Three partition walls 142 and three support shafts 143 erected upward from the top, and an annular plate 144 attached to the upper ends of the partition walls 142 and the support shafts 143 (that is, positions facing the bottom plate portion 141), It is composed of
The three partition walls 142 and the three support shafts 143 are alternately arranged so that the partition walls or the support shafts are equidistant from each other in the circumferential direction.

The planetary gear 150 is formed in a cylindrical shape having a hole into which the support shaft 143 of the carrier 140 is inserted, for example, by a resin material such as plastic or a metal material, and the sun gear 112a described above is fixed to the outer peripheral surface thereof. External teeth that mesh with the ring gear of the gear 120 and the ring gear of the output gear 130 are formed.
The three planetary gears 150 are rotatably inserted into the three support shafts 143 of the carrier 140, respectively. In this state, the annular plate 144 is attached from above, so that the planetary gear 150 supported by the carrier 140 becomes a fixed gear. 120 and the output gear 130 are attached inside.
The carrier 140, the planetary gear 150, and the annular plate 144 constitute a planetary gear assembly.

The auxiliary gear 160 is formed in a cylindrical shape from a resin material such as plastic. The inner peripheral surface of the auxiliary gear 160 is a hole into which the shaft 33 that supports the sun gear 112a is fixed or rotatable, and the outer peripheral surface meshes with the three planetary gears 150 described above. External teeth are formed.
The auxiliary gear 160 is formed with the same number of teeth as the sun gear 112a. However, backlash (gap between the two gears) when the auxiliary gear 160 and the planetary gear 150 mesh with each other is the same as that of the sun gear 112a. The shift amount of the auxiliary gear 160 is set to be different from the shift amount of the sun gear 112a so as to be smaller than the backlash when the planetary gear 150 is engaged.

The tooth width of the sun gear 112a (the length of the teeth formed on the gear in the direction of the gear rotation axis) and the tooth width of the fixed gear 120 are substantially the same as shown in FIG. 2 (that is, the lower end position of the sun gear 112a). The lower end position of the fixed gear 120 is set on the same plane).
Further, the sun gear 112a and the fixed gear 120 are in a position facing each other with the planetary gear 150 interposed therebetween.

Further, the auxiliary gear 160 is in a position facing the output gear 130 across the planetary gear 150. At this time, as described above, the shift amount is set so that the backlash when the auxiliary gear 160 and the planetary gear 150 mesh with each other is smaller than the backlash when the sun gear 112a and the planetary gear 150 mesh with each other. Therefore, the inclination of the planetary gear (an event in which the planetary gear is inclined in the revolving direction of the planetary gear with respect to the support shaft of the carrier), which has been a concern in the conventional planetary gear type reduction gears, is alleviated.
As a result, the planetary gear 150 is engaged with the sun gear 112a at the upper end side, and is engaged with the auxiliary gear 160 at the lower end side, so that the planetary gear 150 is inclined or loose with respect to the support shaft 143. In addition, transmission of rotation with the output gear 130 is also stabilized.

The fixed gear 120 and the output gear 130 are in a shifted relationship with each other, and are configured so that the number of teeth is slightly different from each other.
On the other hand, the carrier 140 that supports the planetary gear 150 is arranged so as to be freely rotatable around the shaft 33.
For this reason, when the planetary gear 150 rotates and revolves in a state where the planetary gear 150 is engaged with the fixed gear 120 and the output gear 130, the output gear 130 rotates with respect to the fixed gear 120.

Therefore, in the planetary gear type reduction gear 100, the rotation of the rotor assembly 110, that is, the rotation input from the sun gear 112a is greatly decelerated through the planetary gear 150 and output from the output shaft 131 of the output gear 130. .
Then, as described above, the rotation of the output shaft 131 is converted through the screw shaft 42 of the valve body drive mechanism 40 so that the valve body 23 can be moved forward and backward.
With these structures, the planetary gear speed reduction device 100 according to the present invention includes the auxiliary gear 160 that rotates coaxially with the sun gear 112a with respect to the shaft 33 between the sun gear 112a and the bottom plate portion 141 of the carrier 140. Since the meshing length of the gear 150 and the sun gear 112a can be shortened, the transmission efficiency of the rotation between the sun gear 112a and the planetary gear 150 can be improved.

The present invention is not limited to the above-described embodiments, and various modifications can be made.
That is, in the above-described embodiment, by setting the shift amount of the auxiliary gear 160 to a value different from the shift amount of the sun gear 112a, the backlash when the auxiliary gear 160 and the planetary gear 150 mesh with each other is reduced with the sun gear 112a. Although the case where it becomes smaller than the backlash at the time of meshing with the planetary gear 150 is illustrated, it is natural that the backlash may be adjusted by simply changing the tooth thickness.

DESCRIPTION OF SYMBOLS 10 Planetary gear type motor operated valve 20 Valve main body 21 Valve chamber 22 Orifice 23 Valve body 24 Spring receiving member 25 Spring 30 Can 31 Receiving member 32 Shaft holding member 33 Shaft 40 Valve body drive mechanism 41 Cylindrical bearing 42 Screw shaft 43 Ball 44 Ball Support member 50 Motor excitation device 51 Stator coil 52 Connector 53 Lead wire 54 Attachment 100 Planetary gear type reduction device 110 Rotor assembly 111 Tube portion 112 Bottom portion 112a Sun gear 120 Fixed gear 121 Support member 130 Output gear 131 Output shaft 140 Carrier 141 Bottom plate portion 142 Partition wall 143 Support shaft 144 Annular plate 150 Planetary gear 160 Auxiliary gear

Claims (6)

A sun gear supported by a shaft;
A fixed gear fixed concentrically with the sun gear;
A planetary gear meshing simultaneously with both the sun gear and the fixed gear;
A carrier comprising a bottom plate portion that rotates about the central axis of the shaft and a support shaft that rotatably supports the planetary gear;
An output gear meshing with the planetary gear;
A planetary gear speed reducer including
A planetary gear type reduction device further comprising an auxiliary gear that rotates concentrically with the sun gear and meshes with the planetary gear between the sun gear and the bottom plate portion of the carrier. The sun gear and the fixed gear have tooth widths such that the meshing widths with the planetary gears are substantially the same, respectively.
The planetary gear type reduction gear according to claim 1. The auxiliary gear is different in gear shape from the sun gear,
The planetary gear type reduction gear according to claim 1 or 2. The auxiliary gear is formed in such a shape that a backlash when the auxiliary gear and the planetary gear mesh with each other is smaller than a backlash when the sun gear and the planetary gear mesh with each other.
The planetary gear type reduction gear according to claim 3. The auxiliary gear is formed of a resin material,
The planetary gear type reduction gear device according to any one of claims 1 to 4.   A motor-operated valve comprising the planetary gear type reduction gear according to any one of claims 1 to 5.

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