JP2015194187A - Planetary gear device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a planetary gear device in which backlash can be adjusted to a desired value with a simple configuration.SOLUTION: In a planetary gear device 100 in which an internal gear 4 in which internal teeth 4b are formed is screwed to a body 1 with a screw, and which includes a planetary gear 5 comprising a large diameter gear 5a meshed with a sun gear 3a provided coaxially with the internal gear 4 and a small diameter gear 5b meshed with the internal gear 4, the internal teeth 4b and the small diameter gear 5b are made to be a taper gear. By adjusting a rotational position of the internal gear 4 with respect to the body 1, a relative position in an axial direction of the internal gear 4 and the small diameter gear 5b is adjusted, and backlash between the internal teeth 4b and the small diameter gear 5b is adjusted. After adjusting the rotational position of the internal gear 4, by plastically deforming the body 1, the internal gear 4 is fixed to the body 1.

Description

  The present invention relates to a planetary gear device having a planetary gear provided with two stepped gears, and more particularly to backlash adjustment.

  As shown in Patent Document 1, the planetary gear teeth meshing with the sun gear or the internal gear of the planetary gear device are tapered gears whose tooth thickness continuously increases in the tooth trace direction, and the planetary gear is disc spring in the tooth trace direction. There is a planetary gear device that reduces backlash at the meshing portion by being urged by. (Patent Document 1)

JP-A-6-272740

  In the conventional planetary gear device described in Patent Document 1, it is possible to move the planetary gear by elastic deformation of the disc spring, and the backlash is set to 0 by increasing the tooth thickness of the tapered gear corresponding to the distance of this movement. Can do. When the backlash is zero, both surfaces of the teeth are in contact with each other at the meshing portion, and a contact surface pressure is generated due to the biasing force of the disc spring. In order to prevent an adverse effect due to an excessive contact surface pressure, an elastic deformation mechanism for displacing the planetary gear in the radial direction is provided. That is, in the conventional planetary gear device, the backlash is set to 0, but a special mechanism is required to prevent excessive contact surface pressure.

  The present invention has been made in view of the above circumstances, and provides a planetary gear device capable of adjusting the backlash to a desired value with a simple structure.

  In order to solve the above-mentioned problems, the invention according to claim 1 is characterized in that a main body having a screw formed on the inner periphery, an inner tooth formed on the inner periphery, and a screw on the female screw coaxial with the inner tooth on the outer periphery. An internal gear screwed to the main body, a sun gear provided coaxially with the internal gear, a large-diameter gear meshing with the sun gear, and a small-diameter gear meshing with the internal gear In the planetary gear device including the planetary gear, the internal gear and the small diameter can be obtained by adjusting at least one of the internal gear and the small diameter gear as a tapered gear and adjusting the rotational position of the internal gear with respect to the main body. The backlash between the internal teeth and the small diameter gear is adjusted by adjusting the relative position in the axial direction of the gear.

  The invention according to claim 2 is characterized in that, in the invention according to claim 1, after adjusting the rotational position of the internal gear with respect to the main body, the main body is plastically deformed to fix the internal gear to the main body. It is to be.

  According to the first aspect of the invention, by rotating the internal gear, the axial relative position of the internal gear and the small-diameter gear is adjusted by screw feed, and the backlash between the internal gear and the small-diameter gear is adjusted. can do. Since the adjustment is performed by screw feeding, a minute relative position can be adjusted, and a planetary gear device capable of precisely adjusting the backlash can be provided.

  According to the second aspect of the invention, after the planetary gear device is assembled, the internal gear can be rotated to adjust the backlash and the main body can be plastically deformed to fix the internal gear to the main body. It is possible to provide a planetary gear device that includes a backlash and can securely fix the internal gear in a short time.

  According to the present invention, it is possible to provide a planetary gear device that can adjust the backlash to a desired value with a simple structure.

It is the schematic which shows the cross section (BB cross section of FIG. 2) of this embodiment. It is AA sectional drawing of FIG. It is a figure which shows the temporary assembly | attachment state of the planetary gear apparatus of this embodiment.

Hereinafter, the structure of the planetary gear device 100 according to the embodiment of the present invention will be described with reference to the drawings. In FIG. 1, the right side of the drawing is the front of the planetary gear device 100, and the left side of the drawing is the rear of the planetary gear device 100.
As shown in FIG. 1, the first carrier 6 is rotatably supported by a first bearing 10 attached to the front inner side of the main body 1. The second carrier 7 is rotatably supported by a second bearing 11 attached to the rear inner side of the main body 1. The first carrier 6 and the second carrier 7 are coupled by a connecting rod 9 and rotate integrally. An output member (not shown) is attached to the first carrier 6.

  The internal gear 4 is supported by a male screw 4 a formed on the outer peripheral surface of the internal gear 4 being screwed into a female screw 1 a formed on the inner peripheral surface of the main body 1 between the first carrier 6 and the second carrier 7. Has been. The internal gear 4 is fixed by being plastically deformed from the outer periphery after being rotated and positioned at a desired position in the axial direction. Inner teeth 4b are formed on the inner peripheral portion of the internal gear 4, and the inner teeth are involute taper gears, and the transition coefficient continuously changes in the direction of the tooth trace, so that the same radius is obtained. The tooth thickness changes continuously in the direction of the tooth trace. In the present embodiment, the tooth thickness is increased toward the front.

  The input shaft 3 includes a sun gear 3a at the center, and is rotatably supported by a third bearing 12 attached to the center of the first carrier 6 and a fourth bearing 13 attached to the center of the second carrier 7. ing. With such a configuration, the input shaft 3 is rotatably supported by the main body 1 coaxially with the internal gear 4. In the present embodiment, the input shaft 3 is connected to a power source such as a motor.

  A plurality of shafts 8 are fixed to the first carrier 6 and the second carrier 7 around the outer periphery of the input shaft 3. A planetary gear 5 and thrust collars 15 and 16 are attached to each shaft 8 so that they can rotate and cannot move in the axial direction. The planetary gear 5 includes a large-diameter gear 5a that meshes with the sun gear 3a and a small-diameter gear 5b that meshes with the internal teeth 4b of the internal gear 4. Greater than twice. The small-diameter gear 5b is a tapered gear and is formed so that the tooth thickness decreases toward the front. The teeth may be spur gears or helical gears.

(Backlash of planetary gear unit)
The backlash of the planetary gear device 100 will be described below. The backlash amount of the planetary gear device 100 is defined as a rotation angle at which the first carrier 6 can freely rotate with the input shaft 3 fixed, and is referred to as backlash Φ. Backlash Φ is the backlash B ₁ is a gap on the pitch circle in the meshing portion of the sun gear 3a and the large diameter gear 5a, the gap on the pitch circle in the meshing portion of the internal 4b and the small diameter gear 5b of the internal gear 4 caused by backlash _{B 2} is. Here, the pitch circle radius of the large-diameter gear 5a and R _1, the pitch circle radius of the small diameter gear 5b and R _2, the pitch circle radius of the internal 4b of the internal gear 4 and Ru.

Assuming that the rotation angle at which the first carrier 6 can freely rotate due to the backlash B ₁ is the backlash Φ ₁ and the rotation angle at which the first carrier 6 can be freely rotated due to the backlash B ₂ is the backlash Φ ₂ , the backlash Φ = Φ ₁ + Φ ₂ The amount by which the planetary gear 5 can be freely rotated by the backlash B ₁ is B ₁ / R ₁ (rad), and the backlash Φ ₁ by this is Φ ₁ = (B ₁ / R ₁ ) · (R ₂ / Ru) (rad) It becomes. The amount by which the planetary gear 5 can freely rotate by the backlash B ₂ is B ₂ / R ₂ (rad), and the backlash Φ ₂ by this is Φ ₂ = (B ₂ / R ₂ ) · (R ₂ / Ru) (rad) It becomes.

In this embodiment, since R ₁ = 2 · R ₂ , 2 · Φ ₁ = Φ ₂ when the backlashes B ₁ and B ₂ are equal. Against backlash [Phi, a large contribution of backlash B ₂ of the engagement portion of the internal 4b and the small diameter gear 5b. Therefore, it is possible to effectively adjust the backlash Φ by adjusting the backlash B ₂ of the engagement portion of the internal 4b and the small diameter gear 5b.

(Backlash adjustment method)
The backlash adjustment method will be described below.
As shown in FIG. 3, the planetary gear device 100 is temporarily assembled. At this time, the position of the axial direction of the internal gear 4 is a position where the backlash B ₂ in the meshing portion of the internal 4b and the small diameter gear 5b is assumed to be a predetermined amount.
Next, the backlash Φ is measured by rotating the first carrier 6 with the input shaft 3 fixed. At this time, in order for the internal gear 4 not to rotate, it is convenient that the frictional force between the main body 1 and the internal gear 4 is large to some extent. For this purpose, an elastic member 17 that urges the planetary gear 5 in the axial direction is provided.

Next, the first carrier 6 is connected to the main body 1 to prevent relative rotation. When the input shaft 3 is rotated in this state, the internal gear 4 can be rotated in a desired direction via the planetary gear 5. When reducing the backlash Φ, the internal gear 4 is rotated in the direction of moving backward, and when increasing the backlash Φ, the internal gear 4 is rotated in the direction of moving forward.
When the desired backlash Φ can be set, as shown in FIG. 1, the outer periphery of the position where the internal gear 4 of the main body 1 is screwed is pressed with a punch to form the plastic deformation portion 1c, and the internal gear 4 Is fixed to the main body 1.

  As apparent from the above description, after the planetary gear device 100 is temporarily assembled, the backlash of the planetary gear device 100 as a whole can be adjusted to a desired amount by adjusting a portion that greatly contributes to the backlash.

In the present embodiment, both the internal teeth 4b and the small-diameter gear 5b are tapered gears. However, when the transmission torque is small, only one of the internal teeth and the small-diameter gear may be a tapered gear and the other may be provided with a crowning. Good.
Further, when the gear is formed by forging or casting, the draft may be tapered.

1: Main body 1a: Female screw 1c: Plastic deformation part 3: Input shaft 3a: Sun gear 4: Internal gear 4a: Male screw 4b: Internal tooth 5: Planetary gear 5a: Large diameter gear 5b: Small gear 6: First carrier 7: First Two carrier 8: Shaft 9: Connecting rod 10: First bearing 11: Second bearing 12: Third bearing 13: Fourth bearing 15, 16: Thrust collar 17: Elastic member

Claims (2)

A main body with an internal thread formed on the inner periphery;
An internal gear formed on the inner circumference, and formed on the outer circumference a male screw that is screwed to the female screw coaxial with the inner tooth, and is screwed to the main body;
A sun gear provided coaxially with the internal gear;
In a planetary gear device including a planetary gear composed of a large-diameter gear meshing with the sun gear and a small-diameter gear meshing with the internal gear,
At least one of the internal teeth and the small diameter gear is a tapered gear,
By adjusting the rotational position of the internal gear with respect to the main body, the relative position in the axial direction of the internal gear and the small-diameter gear is adjusted, and a planetary gear that adjusts the backlash between the internal teeth and the small-diameter gear. Gear device.   2. The planetary gear device according to claim 1, wherein after the rotational position of the internal gear with respect to the main body is adjusted, the main body is plastically deformed to fix the internal gear to the main body.

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