JPH0953707A - Grease supply mechanism of wave-motion gear device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To sufficiently lubricate working tooth flanks of a rigid internal gear and a flexible external gear in a wave-motion gear device and remove efficiently abrasion powder occurring at this position. SOLUTION: In a wave-motion gear device face 71 of a cover 7 on input side, disposed on outer periphery of an input shaft 5, so that grease dispersed from a rotating, wave motion generator 4 and a flexible external gear 3 is collected. Grease thus collected is led into a grease path 74 inclined down within the input side, cover 7, then flows down and flows into a grease path 25 within a rigid internal gear 2, so that it is supplied to meshing portions of internal teeth 2a and external teeth 3a. When the device starts rotation, grease supply is started automatically, so that the meshing portions are lubricated sufficiently and abrasion powder occurring with the meshing is efficiently removed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a grease supply mechanism for supplying grease to each lubrication target portion of a wave gear device, and particularly to a meshing tooth surface of a rigid internal gear and a flexible external gear. The present invention relates to a grease supply mechanism for supplying the.

[0002]

2. Description of the Related Art A typical wave gear device includes an annular rigid internal gear and a cup-shaped flexible external gear arranged inside thereof, and has a wave generator having an elliptical contour shape. Thus, the flexible externally toothed gear is flexed in the radial direction, and the external teeth are brought into mesh with the internal teeth at two locations in the major axis direction. An input shaft is connected to the wave generator, and high speed rotation is input to the input shaft. When the wave generator rotates at high speed, the meshing position between the internal gear and the external gear also moves in the circumferential direction accordingly. The internal gear and the external gear usually have a difference in the number of teeth of two sheets, and are fixed so that the internal gear does not rotate. Therefore, when the mesh position moves, the external gear rotates relative to the fixed internal gear at a rotation speed that is significantly reduced compared to the input rotation. The rotation of the external gear is taken out as an output.

In this way, the meshing tooth surfaces of the internal gear and the external gear are intermittently meshed with each other while relatively approaching and separating in the radial direction, and power is transmitted. Therefore, it is necessary to sufficiently lubricate this meshing tooth surface portion.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to provide a grease supply which can sufficiently lubricate the tooth surfaces of a rigid internal gear and a flexible external gear in a wave gear device. To propose a mechanism.

[0005]

In order to solve the above-mentioned problems, the present invention provides an annular rigid internal gear, an annular flexible external gear arranged inside the annular internal gear, and a flexible external gear. The external gear is flexed in the radial direction and is meshed with the rigid internal gear at a plurality of points, and the meshing positions are moved in the circumferential direction. In a wave gear device having a wave generator for generating relative rotation between toothed gears and an input shaft coaxially connected to the wave generator for rotating the wave generator, the input shaft An annular input side cover arranged on the outer periphery of the input side cover, a grease reservoir formed on an annular end surface of the input side cover facing the wave generator and the flexible external gear, and the input side cover. Is formed inside A cover-side grease passage, one end of which is open to the grease reservoir, and one end of which is formed inside the rigid internal gear and communicates with the cover-side grease passage, and the other end of which is an internal tooth of the rigid internal gear. A configuration having an internal gear side grease passage open to the forming portion is adopted.

Here, the cover-side grease passage and the internal gear side grease passage communicating with the cover-side grease passage are generally directed downward from the cover-side grease passage toward the internal gear-side grease passage. It is desirable to construct it so as to form an inclined passage.

[0007]

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

FIG. 1 (A) shows a half cross section of a wave gear device to which the present invention is applied, and FIG. 1 (B) shows its side surface. As shown in these drawings, the wave gear device 1 is of a generally known type called a cup type, and includes an annular rigid internal gear 2 and a cup-shaped movable gear arranged inside. It is basically composed of a flexible externally toothed gear 3 and a wave generator 4 having an elliptical contour mounted inside thereof.

The rigid internal gear 2 has a rectangular cross section, and internal teeth 2a are formed on its inner peripheral surface. The cup-shaped flexible externally toothed gear 3 has a tubular body portion 31, an annular diaphragm 32 continuous to one end thereof, and a thick wall integrally formed at the center of the diaphragm 32. Bosses 33, and outer teeth 3a are formed on the outer peripheral surface of the body 31 on the open end side. The wave generator 4 includes a hub 41 to which the input shaft 5 is fitted and fixed in a central hole, an elliptical contour-shaped plug 42 fitted to the outer periphery of the hub 41, and a ball fitted to the outer peripheral surface of the plug 42. The bearing 43 is provided.

An input shaft 5 is coaxially fixed to the wave generator 4, and the input shaft 5 is connected to a rotary drive source such as a motor. The input shaft 5 is a bearing 6
It is rotatably supported on the inner peripheral surface of the annular input-side cover 7 via. As the input side cover 7, for example, a component of a casing of a rotary drive source such as a motor may be used as it is. On the other hand, the output shaft 8 is coaxially fixed to the boss 33 of the cup-shaped flexible external gear 3. The output shaft 8 is rotatably supported by a bearing 9 on the inner periphery of a device housing 11 such as an actuator in which the wave gear device 1 is incorporated.

As can be seen from FIG. 1A, one annular end surface 21 of the rigid internal gear 2 is closely fixed to the annular end surface 11a of the apparatus housing 11. The other annular end surface 22 of the rigid internal gear 2 is closely fixed to one annular end surface 71 of the input side cover 7.

Here, an annular groove having a rectangular cross section is carved as a grease reservoir 72 on the annular end surface 71 of the input side cover 7. An upper end opening 74a of a grease passage 74 formed inside the input side cover 7 is opened on an outer peripheral surface 73 defining the bottom surface of the grease reservoir 72. The grease passage 74 includes an upper horizontal portion 74b extending from the upper end opening 74a in the direction of the axis 1a, an inclined portion 74c extending downwardly from the upper horizontal portion 74b as shown in FIG.
The lower horizontal part 74d extends from the lower end of 4c in the direction of the axis 1a in the direction opposite to the upper horizontal part 74b. A tip 74e of the lower horizontal portion 74d is opened to the annular end surface 71 of the input side cover 7.

On the other hand, a grease passage 25 is also formed inside the rigid internal gear 2.

The grease passage 25 has a first horizontal portion 25a extending in the direction of the axis 1a and a second horizontal portion 25b extending inward in the radial direction from the tip of the horizontal portion 25a. ing. The opening 25c on the base end side of the first horizontal portion 25a communicates with the opening 74e of the lower horizontal portion 74d of the grease passage 74 formed in the input side cover 7. Further, the tip end opening 25d of the second horizontal portion 25b is opened substantially at the center in the tooth trace direction of the portion where the internal teeth 2a are formed.

FIG. 2 schematically shows the grease passages formed by the grease passages 74 and 25 formed inside the input side cover 7 and the rigid internal gear 2, respectively. As can be seen from this figure, the grease accumulated in the grease reservoir 72 of the input side cover 7 flows down inside the grease passage 74 inside the input side cover and enters the grease passage 25 inside the rigid internal gear 2, where Through the inner teeth 2a.

The wave gear device 1 of the present embodiment thus configured
Are assembled in the state shown in FIG. That is, the grease passage 74 formed inside the input side cover 7 is shown in FIG.
It is assembled so as to be in an inclined state as shown in (B).

When the wave gear device 1 assembled in this way is driven, grease is supplied to the meshing tooth surfaces of the inner teeth and the outer teeth as follows. When the wave generator 4 rotates at high speed, the lubricating grease adhering to the wave generator itself scatters outward. Since the grease reservoir 72 of the input side cover 7 is formed on the side of the wave generator 4 so as to face it, a part of the scattered grease is trapped in the grease reservoir 72 and accumulated there. Further, as the wave generator 4 rotates, the open end of the flexible external gear 3 on which the external teeth 3a are formed is repeatedly bent in the radial direction. Due to the so-called pumping effect generated by such bending, the grease supplied to the inside of the flexible externally toothed gear 3 is extruded toward the open end side, and the grease reservoir 72 formed at a position facing this is stored. Accumulate in.

When the grease is stored in the grease reservoir 72 in this manner, the upper horizontal portion 7 of the grease passage 74 is formed on the bottom surface.
Since the opening 74a of 4b is located, this opening 74a
From the grease enters the grease passage 74. Grease passage 74
Since a slanted portion 74c slanting downward is formed as a whole, the grease flows down by its own weight along the slanted portion 74c. Then, the oil is supplied to the meshing tooth surface side through a horizontal grease passage 25 formed inside the rigid internal gear 2.

Further, during operation, the pressure inside the flexible external gear 2 tends to rise as compared with the surroundings, and this rise in pressure accelerates the supply of grease.

As described above, in the grease supply mechanism of the wave gear device of this embodiment, when the wave generator 4 rotates, the grease is continuously supplied to the meshing tooth surfaces, so that the lubrication of this portion is sufficient. Can be Further, by such a grease supplying operation, the initial wear powder on the meshing tooth surface can be efficiently removed, so that the life of the apparatus can be extended.

It should be noted that a filter may be installed in the grease passage or at the open end portion thereof so that the abrasion powder generated on the meshing tooth surface does not recirculate through the grease passages 74 and 25.

The supply amount of grease can be controlled by appropriately adjusting the consistency of grease.

Further, it goes without saying that the grease passages 74 and 25 may be filled with grease in advance.

[0024]

As described above, in the grease supply mechanism of the wave gear device of the present invention, attention is paid to the input side cover attached to the outer periphery of the input shaft connected to the wave generator of the wave gear device. Utilizing the inside, it captures grease scattered from the rotating wave generator and the flexible external gear, and guides it to a grease passage inclined downward, and through this grease passage, the internal gear and It is supplied to the meshing tooth surface of the external gear. Therefore, according to the present invention, it is possible to supply the grease to the meshing tooth surface with the rotation of the wave generator, to sufficiently lubricate this portion, and to efficiently remove the initial abrasion powder and the like. You can

[Brief description of drawings]

FIG. 1 is a view showing a wave gear device to which the present invention is applied, (A) is a schematic half sectional view thereof, and (B) is a side view thereof.

FIG. 2 is an explanatory view for explaining a grease distribution path formed by the grease passages of FIG. 1;

[Explanation of symbols]

 1 wave gear device 1a axis 2 rigid internal gear 2a internal tooth 25 grease passage 25a first horizontal portion 25b second horizontal portion 25c, 25d opening 3 flexible external tooth gear 3a external tooth 4 wave generator 5 input shaft 6 Bearing 7 Input side cover 72 Grease reservoir 74 Grease passages 74a, 74e Opening 74b Upper horizontal part 74c Inclined part 74d Lower horizontal part 8 Output shaft 9 Bearing

Claims (2)

[Claims] 1. An annular rigid internal gear, an annular flexible external gear arranged inside the annular internal gear, and the flexible external gear is bent in the radial direction to provide the rigidity at a plurality of points. Along with meshing with the internal gear, by moving these meshing positions in the circumferential direction, a wave generator that generates relative rotation between the rigid internal gear and the flexible external gear,
In a wave gear device having an input shaft coaxially connected to the wave generator for rotating the wave generator, an annular input side cover arranged on the outer periphery of the input shaft, A grease reservoir formed on an annular end surface of the input side cover facing the wave generator and the flexible external gear, and an end formed in the input side cover and open at the grease reservoir. The cover-side grease passage is formed inside the rigid internal gear, and one end communicates with the cover-side grease passage and the other end is open to the internal tooth forming portion of the rigid internal gear. A grease supply mechanism for a wave gear device, comprising: a tooth gear side grease passage. 2. The cover-side grease passage and the internal-toothed gear-side grease passage communicating with the cover-side grease passage as a whole from the cover-side grease passage toward the internal-toothed gear-side grease passage according to claim 1. A grease supply mechanism for a wave gear device, which has an inclined passage that is inclined downward.