JPH11344084A - Reduction gear using eccentric gear - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a reduction gear using an eccentric gear of such structure that the dynamic unbalance is adjustable without bringing about complication to the structure. SOLUTION: This reduction gear using an eccentric gear is at least composed of a first external gear 10 supported at the center, a second external gear 12 supported at the center by a shaft installed in a position eccentrical from the rotational center of the first external gear, and an internal gear concentrical with the first external gear where the second external gear is meshing, wherein a disc part on the first external gear is furnished partially with a portion 10a having a greater wall thickness than the other portions, and a balance weight 19 is installed rigidly on a bearing bushing of the first external gear, and thereby it is practicable to adjust the position of the center of gravity of the first external gear in the condition that the second external gear is supported.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a speed reducer used for an actuator of a constant speed traveling device for an automobile, for example, and more particularly to a speed reducer using an eccentric gear.

[0002]

2. Description of the Related Art A second external gear is eccentrically supported relative to a first external gear so as to be rotatable relative to the first external gear, and power is taken out from the internal gear in which the second external gear is inscribed. Such a speed reducer is known (see JP-A-63-190954).

[0003]

A reduction gear of this type is
A relatively large reduction ratio can be obtained with a compact configuration,
As for the first external gear, since the second external gear is mounted at an eccentric position, the position of the center of gravity must be inconsistent with the center of rotation. Such an unbalance of the rotating body causes considerable vibrations when the rotating speed is increased. Therefore, in general, the thickness of the rotating body is made non-uniform in the circumferential direction, or by adding a balance weight to the center of gravity of the rotating body. The position is made to coincide with the center of rotation.

The static imbalance in the direction perpendicular to the rotation axis can be adjusted relatively easily by changing the thickness of the disk portion of the first external gear in the circumferential direction.
Eliminating the axial dynamic imbalance was extremely cumbersome, which resulted in insufficient reduction in vibration levels. Therefore, to meet the desire to provide an eccentric gear near the input stage for reasons such as layout reasons and the balance between strength and dimensions, the rotation speed of the input stage is relatively high, so it can be satisfied satisfactorily. Could not.

The present invention solves the problems imposed on the prior art and reduces the speed by using an eccentric gear configured to be able to adjust the dynamic imbalance without complicating the structure. It has been devised for the purpose of providing.

[0006]

In order to achieve the above object, according to the present invention, a first external gear 10 whose center is supported and the first external gear are attached to the first external gear. A second external gear 12 whose center is supported by a shaft provided at a position eccentric to the rotation center of the external gear, a first external gear with which the second external gear meshes; In a reducer using an eccentric gear having at least a concentric internal gear 14,
By providing a portion 10a thicker than the other portion on a part of the disk portion of the first external gear, and integrally providing a balance weight 19 on a bearing bush 18 of the first external gear, the second The position of the center of gravity of the first external gear while supporting the external gear is adjusted.

[0007]

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings.

FIGS. 1 and 2 show an electric actuator for cruise control to which the present invention is applied. The actuator 1 functions to increase or decrease the traction force applied to a wire connected to a throttle valve using the electric motor as a power source. The electric motor 3 housed in a common casing 2, a speed reducer 4, and a speed reducer 4, a sector gear 5 driven by a final reduction gear, a semicircular sheave 7 around which a wire 6 connected to a throttle lever is wound, and a connection between the sector gear 5 and the semicircular sheave 7 is intermittently interrupted as required. And an electromagnetic device 8.

The reduction gear 4 has a primary reduction gear 10 meshed with a pinion 9 fixed to the output shaft of the electric motor 3, and a ball bearing 11 on the lower surface of the primary reduction gear 10 at a position eccentric from the center of the primary reduction gear 10. Secondary reduction gear 1 supported through
2, a fixed internal gear 13 which is concentric with the primary reduction gear 10 and is substantially integral with the casing 2, and has a smaller number of teeth than the fixed internal gear 13 and rotates coaxially with the primary reduction gear 10. Rotating internal gear 14 and rotating internal gear 14
And a final reduction gear 15 formed on a common member.

The primary reduction gear 10 rotates about a first fixed shaft 16 erected on the bottom wall of the casing 2. The secondary reduction gear 12 includes a fixed internal gear 13 and a rotary internal gear 1.
4 and revolves around the first fixed shaft 16 while rotating around the eccentric shaft as the primary reduction gear 10 rotates. The rotation of the secondary reduction gear 12 causes the primary reduction gear 10 to rotate.
At the same time, the rotating internal gear 14 pivotally mounted on the first fixed shaft 16 rotates, and a rotational force is output from the final reduction gear 15 integrated with the rotating internal gear 14.

The sector gear 5 meshed with the final reduction gear 15
Is pivotally attached to a second fixed shaft 17 erected on the bottom wall of the casing 2 so as to be parallel to the first fixed shaft 16.

When the electric motor 3 is rotated, the primary reduction gear 10 meshed with the pinion 9 rotates. This torque is transmitted to the secondary reduction gear 12 via the ball bearing 11. Since the fixed internal gear 13 does not rotate, the secondary reduction gear 12 revolves while rotating on its inner periphery.
4, the rotational force of the secondary reduction gear 12 is transmitted to the rotating internal gear 14. As a result, the final reduction gear 15 integrated with the rotating internal gear 14 rotates. Since the central axis of the final reduction gear 15 is fixed to the casing 2, the sector gear 5 meshed with this rotates. Then
A semicircular sheave 7 pivotally attached to a second fixed shaft 17 common to the sector gear 5 and adsorbed by an electromagnetic device 8 integral with the sector gear 5 rotates together with the sector gear 5 and a wire 6 connected to a throttle lever. To adjust the throttle opening. If the electromagnetic device 8 is demagnetized and the connection between the semicircular sheave 7 and the sector gear 5 is cut off, the traction force on the wire 6 is extinguished, the throttle lever is returned to the initial position by a separately provided return spring, and the semicircular sheave 7 is also returned to the initial position.

In the speed reducer 4 as described above, the primary reduction gear 10 is provided with the ball bearing 11 and the secondary reduction gear 12 at positions deviated from the center of rotation. The position of the center of gravity is the secondary reduction gear 12
It will be closer to you. For this reason, when the primary reduction gear 10 is rotated, the direction of action of the inertial force moves with the rotation, and vibration is generated. Further, since the gear has a length in the axial direction, vibration cannot be eliminated unless balance in the radial direction and balance in the axial direction are simultaneously performed. Therefore, in the present invention, the thickness distribution of the disk portion of the primary reduction gear 10 is made non-uniform in the circumferential direction (specifically, the thick portion 10a
And a balance weight 19 is integrally formed with the bearing bush 18 that is press-fitted into the primary reduction gear 10. Thereby, the position of the center of gravity of the primary reduction gear 10 in a state where the secondary reduction gear 12 is assembled can be matched with the rotation center.

With reference to the center of gravity A in the axial direction when the primary reduction gear 10 and the secondary reduction gear 12 are viewed integrally, the center of gravity of the balance weight 19 provided on the bearing bush 18 with respect to the axis is determined. The interval from B to h1
And the distance from the center of gravity C in the axial direction of the disk thick portion 10a of the primary reduction gear 10 is h2, and h
When 1 + h2 = b (see FIG. 3), the relationship between the correction amount U1 by the thick portion 10a of the primary reduction gear 10 and the correction amount U2 by the balance weight 18 of the bearing bush 18 with respect to the entire unbalance correction amount U is as follows. By setting as follows, correction including dynamic imbalance is possible.

U1 = U · h2 / b U2 = U · h1 / b

[0016]

As described above, according to the present invention, the mass distribution in the circumferential direction of the disk portion of the first external gear is made non-uniform, and the balance weight is provided on the bearing bush of the first external gear. By integrally providing, by adjusting the position of the center of gravity of the first external gear in a state where the second external gear is supported, unbalance in the radial direction and the axial direction can be achieved without complicating the structure. Adjustable. Therefore, vibration is not generated even at a high rotation speed, so that it is possible to arrange the eccentric gear on the input stage side where the rotation speed is relatively high and the gear load is relatively small, and the reduction gear is reduced in size and weight. A great effect can be achieved in promoting the conversion.

[Brief description of the drawings]

FIG. 1 is a plan view of an actuator to which the present invention is applied.

FIG. 2 is a longitudinal sectional view taken along the line II-II in FIG.

FIG. 3 is an explanatory diagram of a center of gravity position.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Actuator 2 Casing 3 Electric motor 4 Reducer 5 Sector gear 6 Wire 7 Semicircle sheave 8 Electromagnetic device 9 Pinion 10 Primary reduction gear 11 Ball bearing 12 Secondary reduction gear 13 Fixed internal gear 14 Rotating internal gear 15 Final reduction gear 16 1 fixed shaft 17 second fixed shaft 18 bearing bush 19 balance weight

Claims (1)

[Claims] 1. A first external gear whose center is supported, and a first external gear having a shaft provided at a position eccentric to a rotation center of the first external gear. A speed reducer using an eccentric gear having at least a second external gear supported at the center and an internal gear concentric with the first external gear meshed with the second external gear. By making the mass distribution in the circumferential direction of the disk portion of the first external gear non-uniform and providing a balance weight integrally with the bearing bush of the first external gear, the second The first gear supporting the external gear;
A reducer using an eccentric gear, wherein the position of the center of gravity of the external gear is adjusted.