JP6765214B2 - Planetary gear type speed reducer and motorized valve equipped with this - Google Patents

Description

The present invention relates to a planetary gear type speed reducer and an electric valve provided with the planetary gear type speed reducer, and more particularly to a planetary gear type speed reducer capable of improving durability and an electric valve provided therewith.

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

In the motorized valve described in Patent Document 1, a planetary gear type speed reducer is used as the speed reducer.
Such a planetary gear type reduction gear 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. A plurality of planetary gears arranged between the gears and fixed gears and meshing with these gears, and an output gear for transmitting rotation from the plurality of planetary gears are provided.

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

FIG. 4 shows an outline of a main part of a planetary gear type speed reducer applied to a conventional electric valve, for example, described in Patent Document 1, and FIG. 4A shows rotation in an upper part of a sun gear. It is an enlarged view of the main part of the cross section perpendicular to the axis, and FIG. 4 (b) is a cross-sectional view on the AA plane of FIG. 4 (a).
As shown in FIG. 4A, the solar gear 2 rotatably supported by the shaft 1 rotates in the direction of arrow d1 due to the rotation of the rotor of an electric motor (not shown).

A planetary gear 5 rotatably supported by a plurality of support shafts 4 erected on a carrier (not shown) is provided between the fixed gear (internal gear) 3 fixed to face the sun gear 2 and the sun. It is arranged so as to mesh with both the gear 2 and the fixed gear 3.
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 portion 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. 511240

In the planetary gear type speed reducer as described above, when the sun gear 2 rotates, the planet gear 5 meshing with the sun gear 2 rotates in the direction of arrow d2.
At this time, since the planetary gear 5 also meshes 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. 4A.

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. 4B, the central axis of the support shaft 4 O2 is tilted by an angle θ from the original position O1.
On the other hand, since the support shaft 4 rotatably supports the planetary gear 5, there is a manufacturing clearance (void e) between the support shaft 4 and the planetary gear 5.

When the tilt angle θ and the gap e as described above occur, the planetary gear 5 comes into contact with the sun gear 2 or the fixed gear 3 with the rotation axis tilted.
If the planetary gear 5 and the sun gear 2 or the fixed gear 3 are tilted, there is a concern that tooth bottom interference may occur between these gears and the transmission efficiency of the reduction gear may decrease.
Further, when the planetary gear 5 is tilted, there is a concern that the meshing between the sun gear 2, the fixed gear 3, and the planetary gear 5 is biased, the gear is unevenly worn, and the durability of the gear is lowered. ..

Therefore, an object of the present invention is to provide a planetary gear type speed reducer that suppresses a decrease in transmission efficiency of the speed reducer and a decrease in gear durability, and an electric valve provided with the planetary gear type speed reducer.

In order to achieve the above object, the planetary gear type reduction gear according to the present invention includes both the sun gear supported by the shaft, the fixed gear concentrically fixed to the sun gear, and the sun gear and the fixed gear. A carrier composed of a planetary gear that meshes at the same time, 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 that meshes with the planetary gear, and the bottom plate of the carrier. The bottom plate portion includes an annular plate attached to one end of the support shaft at a position facing the portion, and a receiving hole for receiving the tip end portion of the support shaft of the annular plate with respect to the position of the root portion of the support shaft. in the rotational direction is formed in the predetermined angle shift position, so-edge portion of the support shaft is offset in the rotational direction of the bottom plate portion with respect to the root portion of the support shaft, the support shaft is previously predetermined angle you only have inclined obliquely, characterized in that.

In the planetary gear type speed reducer according to the present invention, the predetermined angle of inclination of the support shaft is such that the outer peripheral surface of the tip portion of the support shaft and the inner peripheral surface of the planetary gear are in point contact and the root of the support shaft. An angle at which the outer peripheral surface of the portion and the inner peripheral surface of the planetary gear are in point contact is preset.
Further, the carrier may be made of a resin material.

The planetary gear type speed reducer according to the present invention can be applied to an electric valve.
At this time, the planetary gear type speed reducer is arranged in the internal space of the can fixed to the valve body.

According to the planetary gear type speed reducer according to the present invention, by providing the above-described configuration, it is possible to suppress the inclination of the support shaft that rotatably supports the planetary gear during use, so that the planetary gear rotates and revolves. At the same time, there is no interference of the tooth bottom with the sun gear or the fixed gear.
As a result, uneven wear due to uneven meshing does not occur, so that deterioration of transmission efficiency of the reduction gear and durability of the gear can be suppressed.

It is a vertical cross-sectional view which shows the whole structure of the planetary gear type electric valve to which the planetary gear type speed reducer according to one Example of this invention is applied. It is a figure which shows the outline of the planetary gear type reduction gear shown in FIG. 1, FIG. 2A is a partial cross-sectional view, and FIG. 2B is a sectional view taken along line BB of FIG. 2A. is there. FIG. 3A is a diagram showing a main part of a planetary gear type speed reducer according to an embodiment of the present invention, in which FIG. It is a cross-sectional view in a plane (CC cross-sectional view of FIG. 3 (b)), and FIG. 3 (b) is a top view of a planetary gear assembly including a carrier, a planetary gear, and an annular plate. The outline of the main part of the planetary gear type speed reducer applied to the conventional electric valve is shown, and FIG. 4A is an enlarged view of the main part of the cross section perpendicular to the rotation axis in the upper part of the sun gear. FIG. 4B is a cross-sectional view taken along the plane AA of FIG. 4A.

FIG. 1 is a vertical cross-sectional view showing the overall structure of a planetary gear type motorized valve to which a planetary gear type speed reducer according to an embodiment of the present invention is applied.
The planetary gear type electric valve (hereinafter referred to as “electric valve”) 10 shown in FIG. 1 includes a valve body 20 including a valve chamber 21 inside, a can 30 fixed to the upper end of the valve body 20, and a can 30. A valve body drive mechanism 40 attached to the upper end of the valve body 20 inside, a planetary gear type speed reducer 100 coupled to the valve body drive mechanism 40 inside the can 30, and an arrangement surrounding the outside of the can 30. The motor exciter (stator device) 50 is provided.

The valve body 20 is, for example, a metal member having a bottomed tubular shape, and the valve chamber 21 is internally formed by fixing the tubular bearing 41 of the valve body drive mechanism 40 described later to the opening end of the upper portion. Is formed.
An inflow pipe 26a communicating with the valve chamber 21 is attached to the side portion 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. The outflow pipe 26b is attached.

Inside the valve chamber 21, a valve body 23 that opens and closes the orifice 22 and a spring 25 that urges the valve body 23 upward (in the opening direction of the valve body 23), and a spring provided around the spring 25. The receiving member 24 and the like are arranged.
The valve body 23 has a flange portion 23a formed at the upper end thereof to expand its diameter outward, and a tapered portion 23b formed at the lower end thereof to be inserted into the orifice 22.

The spring receiving member 24 is a tubular member arranged on the outside of the valve body 23, and has a flange portion 24a formed at the upper end thereof to expand the diameter outward, and a step portion 24b 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 arranged between the step portion 24b of the spring receiving member 24 and the lower surface of the flange portion 23a of the valve body 23. With such an arrangement, the spring 25 always urges the flange portion 23a of the valve body 23 upward.

The can 30 is a climax cylindrical thin-walled member, and is attached in a manner of accommodating the top of the valve body 20 via a receiving member 31 fixed to the outer peripheral surface of the valve body 20.
Further, above the internal space of the can 30, a shaft holding member 32 that holds the shaft 33, which is the rotation axis of the planetary gear type speed reducer 100 described later, is fixed.
The can 30 functions as an airtight container that seals the internal space formed between the can 30 and the upper portion of the valve body 20, and the valve body drive mechanism 40 and the planetary gear type speed reducer 100, which will be described later, are provided in the internal space. Contain.

The valve body drive mechanism 40 includes a tubular bearing 41 having an accommodating hole 41a accommodating an output shaft (see reference numeral 131 in FIG. 2) of the planetary gear type speed reducer 100, and the output shaft accommodated in the accommodating hole 41a. It is composed of a screw shaft 42 engaged with the screw shaft 42, a ball 43 with one end of the screw shaft 42 in contact with the ball 43, and a ball support member 44 attached to the top of the valve body 23 to support the ball 43.
The tubular bearing 41 is inserted so as to fit into the opening at the top of the valve body 20, and is in contact with the stepped portion 20a inside the valve body 20 in a manner of sandwiching the flange portion 24a of the spring receiving member 24 described above. It is fixed.
Further, a female screw is formed at the lower end of the accommodating hole 41a of the tubular bearing 41.

A male screw to be screwed with the female screw is formed on the outer periphery of the screw shaft 42, and a plano-convex portion 42a inserted into a slit formed in the output shaft 131 of the planetary gear type speed reducer 100 is formed at the upper end thereof. Is formed.
When the output shaft 131 of the planetary gear type speed reducer 100 is rotated by such a valve body drive mechanism 40, the screw shaft 42 connected to the output shaft 131 is also rotated, whereby the rotational movement of the screw shaft 42 is shafted. It is converted into a forward / backward movement in a direction.
Then, the advancing / retreating motion 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 exciter 50 is a stator coil 51 in which a lead wire is wound around a bobbin, and a connector 52 and a lead wire 53 for supplying electric power to the stator coil 51, which are integrally resin-molded. The 51 is arranged so as to surround the outer peripheral portion of the can 30, and is detachably attached to the can 30 via the attachment 54.
On the other hand, the planetary gear type speed reducer 100 includes a rotor assembly 110 into which a shaft 33 attached to the internal space of the can 30 is inserted and fixed, and in the electric valve 10, the stator coil 51 of the motor exciter 50 and the planet. The rotor assembly 110 of the gear-type speed reducer 100 constitutes a stepping motor as an example of an electric motor.

FIG. 2 is a diagram showing an outline of the planetary gear type speed reducer shown in FIG. 1, FIG. 2 (a) is a partial cross-sectional view, and FIG. 2 (b) is B- of FIG. 2 (a). It is a cross-sectional view of B.
As shown in FIG. 2, the planetary gear type speed reducer 100 is an annular internal gear attached and fixed to the valve body 20 via a support member 121 and an eclipsed cylindrical rotor assembly 110 (see FIG. 1). 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. It includes a carrier 140 arranged inside the 130, and a plurality of planetary gears 150 rotatably supported by the carrier 140.

The rotor assembly 110 shown in FIG. 1 has a tubular portion 111 formed of a resin material such as plastic containing a magnetic material and forming a peripheral wall, and a bottom portion 112 having a solar gear 112a projecting in the center. It is a member formed integrally.
The sun gear 112a has a through hole in the center through which the shaft 33 is inserted, and external teeth that mesh with the planetary gear 150 are formed on the outer peripheral surface.
The tubular portion 111 and the bottom portion 112 may be manufactured and assembled separately, or may be integrally formed.

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

The output gear 130 is a bottomed cylindrical ring gear manufactured by molding a resin material such as plastic, and the output shaft 131 is press-fitted and fixed to a through hole formed in the center thereof.
Internal 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 on the lower end side into which the plano-convex portion 42a of the screw shaft 42 described above is inserted (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 via the coupling (engagement) between the slit and the plano-convex portion, and the output gear 130 and the screw shaft 42 are engaged with each other. Rotate in the same direction.

The carrier 140 is a resin part or a metal part manufactured by molding a resin material such as plastic, and has a bottom plate portion 141 having a through hole in the center into which the shaft 33 is inserted, and the bottom plate portion 141. Three partition walls 142 and three support shafts 143 erected upward from the partition wall 142, and an annular plate 144 attached to the upper end of the partition wall 142 and the support shaft 143 (that is, a position 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 spaced apart from each other in the circumferential direction.

The planetary gear 150 is formed of a resin material such as plastic or a metal material into a tubular shape having a hole into which the support shaft 143 of the carrier 140 is inserted, and the sun gear 112a is fixed on 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, and by attaching the annular plate 144 from above in this state, the planetary gears 150 supported by the carrier 140 are fixed gears. It is mounted inside the 120 and the output gear 130.
The carrier 140, the planetary gear 150, and the annular plate 144 constitute a planetary gear assembly.

The fixed gear 120 and the output gear 130 are in a dislocated 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 that it can freely rotate around the shaft 33.
Therefore, when the planetary gear 150 rotates and revolves in a state of being meshed 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 speed reducer 100, the rotation of the rotor assembly 110, that is, the rotation input from the sun gear 112a, is greatly reduced via 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 so that the valve body 23 can move forward and backward finely via the screw shaft 42 of the valve body drive mechanism 40.

FIG. 3 is a diagram showing a main part of the planetary gear type speed reducer according to an embodiment of the present invention, and FIG. 3 (a) shows the revolution of the planetary gear passing through the center of the support shaft of the carrier in the vicinity of the planetary gear. It is a cross-sectional view in a plane parallel to the direction, and FIG. 3B is a top view of a planetary gear assembly including a carrier, a planetary gear, and an annular plate.
As shown in FIG. 3A, in the planetary gear type speed reducer 100 according to the embodiment of the present invention, the support shaft 143 of the carrier 140 has the tip end portion in the revolution direction of the planetary gear 150 with respect to the root portion. That is, it is inclined so as to be offset by a predetermined angle θ1 in the rotation direction of the bottom plate portion 141).

As shown in FIG. 3B, the receiving hole 144a that receives the tip of the support shaft 143 in the annular plate 144 is located in the revolution direction of the planetary gear 150 with respect to the position of the annular plate in the conventional planetary gear type speed reducer. On the other hand, it is formed at a position shifted by an angle θ2.
As a result, when the planetary gear 150 is inserted into the support shaft 143 of the carrier 140 and assembled, the support shaft 143 is held so as to be tilted by the predetermined angle θ1.

Here, as an example of the predetermined angle θ1 shown in FIG. 3A, the outer peripheral surface of the tip portion and the outer peripheral surface of the root portion of the support shaft 143 and the inner peripheral surface of the planetary gear come into contact with the contact point Pu, respectively. The angle of point contact indicated by the point Pl is set to be the maximum angle.
Further, the tilting direction of the support shaft 143 is opposite to the revolution direction X of the planetary gear 150 (that is, the rotation direction of the bottom plate portion 141) when the output shaft 131 rotates in the direction of pushing down the valve body 23 shown in FIG. Is set to be.

With these structures, in the planetary gear type speed reducer 100 according to the present invention, the support shaft 143 of the carrier 140 receives from the fixed gear 120 and the output gear 130 as the planet gear 150 revolves, that is, the carrier 140 rotates. It is pre-tilted in the direction facing the force.
Therefore, even if the planetary gear 150 receives a force from the fixed gear 120 and the output gear 130 due to the revolution, the inner peripheral surface of the planetary gear 150 is the outer peripheral surface of the support shaft 143 as shown in FIG. 3A. The inclination can be suppressed by making point contact at two points above and below.

Therefore, by suppressing the inclination of the planetary gear 150, the interference of the tooth bottom between the planetary gear 150 and the sun gear 112a and the fixed gear 120 can be suppressed, and as a result, the transmission efficiency of the rotation of the motor is lowered. It can be suppressed.
Further, since the meshing is not biased between the sun gear 112a and the fixed gear 120 and the planetary gear 150, uneven wear of the gear is reduced, and as a result, the durability of the gear can be prevented from being lowered.

The present invention is not limited to the above examples, and various modifications can be made.
For example, the case where the carrier has three support shafts and the number of planetary gears supported by the support shafts is three is illustrated, but if the positions of the support shafts, that is, the arrangement of the planetary gears is evenly spaced, Two or four or more planetary gears may be applied.

10 Planetary gear type electric valve 20 Valve 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 tubular bearing 42 screw shaft 43 ball 44 ball Support member 50 Motor exciter 51 Stator coil 52 Connector 53 Lead wire 54 Fixture 100 Planetary gear type speed reducer 110 Rotor assembly 111 Cylinder 112 Bottom 112a Sun gear 120 Fixed gear 121 Support member 130 Output gear 131 Output shaft 140 Carrier 141 Bottom plate 142 Partition 143 Support shaft 144 Circular plate 150 Planetary gear

Claims (5)

The sun gear supported by the shaft and
A fixed gear that is fixed concentrically with the sun gear,
A planetary gear that meshes with both the sun gear and the fixed gear at the same time,
A carrier composed of a bottom plate portion that rotates around the central axis of the shaft and a support shaft that rotatably supports the planetary gear.
The output gear that meshes with the planetary gear and
An annular plate attached to one end of the support shaft at a position facing the bottom plate portion of the carrier, and
Is a planetary gear type speed reducer including
Said receiving hole for receiving the distal end portion of the support shaft of the annular plate is formed at a position shifted by a predetermined angle in the rotational direction of the bottom plate portion with respect to the position of the root portion of the support shaft,
As previously end of the support shaft is offset in the rotational direction of the bottom plate portion with respect to the root portion of the support shaft, the support shaft is previously only tilted swash's predetermined angle,
A planetary gear type speed reducer characterized by this. The predetermined angle of inclination of the support shaft is such that the outer peripheral surface of the tip portion of the support shaft and the inner peripheral surface of the planetary gear are in point contact, and the outer peripheral surface of the root portion of the support shaft and the inside of the planetary gear The angle at which the peripheral surface is in point contact is preset.
The planetary gear type speed reducer according to claim 1. The carrier is made of a resin material,
The planetary gear type speed reducer according to claim 1 or 2. An electric valve including the planetary gear type speed reducer according to any one of claims 1 to 3. The planetary gear type speed reducer is arranged in the internal space of the can fixed to the valve body.
The electric valve according to claim 4.

Images