JPS63167167A - Rolling ball type differential transmission mechanism - Google Patents

Abstract

PURPOSE:To make the whole size smaller and the rigidity larger, by placing rolling balls along each guide groove between the first and the second movable plates. CONSTITUTION:Guide grooves 15 and 15a which have wave-form epicycloidal curves and epitrochoidal curves are formed on the surface of the first movable plate 4, while guide grooves 16 and 16a which have wave-form hypocycloidal curves and hypotrochoidal curves are formed on the surface of the second movale plate 6. The first and the second movable plates 4 and 6 are positioned to oppose the guide grooves 15 and 15a, and, 16 and 16a each other, and between the first and the second movable plates 4 and 6, rolling balls 17 and 17a are positioned to roll along the guide grooves 15, 15a, and 16, 16a. In such a composition, a compact size is realized while securing a relatively high deceleration ratio, and moreover, the gearing rate is improved and the rigidity of the whole structure can be made larger.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a transmission mechanism configured to obtain a large reduction ratio, and in particular to a rolling ball type differential transmission that is designed to be thinner in the thickness direction. Regarding the mechanism.

[Prior Art] For example, in recent robot technology, the rotational speed of a motor is lowered by a differential speed reduction mechanism as a speed change mechanism to rotate a conveying arm. As this differential reduction mechanism, a gear type reduction gear, a cyclo reduction gear, a harmonic drive reduction gear, and the like have been considered so far.

However, the differential speed reduction mechanism used in robot technology is
In order to ensure control accuracy, the following advantages (1) have been introduced in recent years:
) to (5) are desired. That is, (1) A high reduction ratio can be obtained with a small device.

(2) There is little play such as backlash and high control accuracy.

(3) High engagement ratio and high rigidity.

(4) The inertial force of the rotating part is relatively small and controllability is good.

(5) Low friction and low power loss.

[Problems to be solved by the invention] However, the conventional reducer described above has advantages and disadvantages,
In either case, it is difficult to satisfy all of the advantages (1) to (5). Therefore, the present invention has been devised to overcome these difficulties.The purpose of the present invention is to ensure a relatively high reduction ratio while maintaining a small overall size, no play, high precision, and low rotational inertia. This is an ideal rolling ball type differential transmission that has a high engagement ratio, high rigidity, low friction and low power loss, and has more parts involved in rotation transmission, increasing transmitted torque. There is something about providing a mechanism.

[Means for Solving the Problems] The present invention includes the following constituent requirements. That is, first and second moving plates are arranged to face each other, and each of the first and second moving plates is continuously formed along the circumference of a plurality of concentric circles on the opposing surface of one of the first and second moving plates. between a wave-shaped guide groove and a wave-shaped guide groove formed concentrically so as to face the guide groove on the other side, and the first and second moving plates;
They are respectively disposed across these mutually opposing guide grooves, and rotate the first moving plate while rolling along the guide grooves as the first moving plate rotates with respect to the second moving plate. A rolling ball is provided to change the speed.

[Example] Each example of the present invention will be described below based on the drawings. First, in FIG. 1, reference numeral 1 denotes a casing, and insertion holes 2.3 are formed on the left side and right side of the casing in a state of facing each other. Reference numeral 4 denotes a first moving plate fixed to the right side inside the casing 1, which is disk-shaped and has a through hole 5 in the center that communicates with the insertion port 3. Reference numeral 6 denotes a second moving plate having a similar shape to the first moving plate 4, which is disposed in the casing 1 to face the first moving plate 4, and has a through hole 7 in the center. Reference numeral 8 denotes an eccentric shaft provided in the casing 1, which is inserted through the through hole 5 of the first moving plate 4, and one end as an eccentric portion 8a is connected to the second moving plate 6 via a bearing 9. It is supported by the through hole 7. The other end of the eccentric shaft 8 is supported by the insertion port 3 via a bearing 10, and the portion protruding from the insertion port 3 to the outside is an input portion 11. In this case, the amount of eccentricity of the eccentric shaft 8 is made to correspond to that regarding the guide groove, which will be described later. Reference numeral 12 denotes a disk-shaped adjustment plate, which is disposed inside the casing 1 to face the second adjustment plate 6, and in the center thereof is an output shaft 14 supported in the insertion hole 2 via a bearing 13. installed.

Now, as shown in FIG. 2, the surface of the first moving plate 4 has a semicircular cross section and mutually concentric guide grooves 15.
15a. These guide grooves 15.15a are each formed continuously on a predetermined pitch circle with 10 wave numbers by waveform epicycloid curves and epitrochoid curves as shown in FIG. 3(a). Furthermore, on the surface of the second moving plate 6 facing the first moving plate 4,
As seen in FIG. 2, guide grooves 16.16a are formed which have semicircular surfaces and are concentric with each other. These guide grooves 16.16a are formed by a waveform of a hypocycloid curve and a hypotrochoid curve as shown in FIG. 3(b).
Two wave numbers are continuously formed on a pitch circle having the same dimensions as described above. Here, an epicycloid curve and a hypocycloid curve are curves drawn when a circle with a small diameter is moved in a circumscribed and inscribed state, respectively, to a circle with a predetermined diameter dimension, and an epitrochoid curve and a hypotrochoid curve are , is the locus drawn by the external and internal points in the radial direction for the small diameter, and their wave height dimensions are shown in Figure 3 (a
), (b), the eccentricity is shown by the symbol e. 17.
Reference numeral 17a denotes a rolling ball made of steel, for example, and these balls are provided in the wave number of 15. 15.15a and 16.16a at equal intervals, and as the second moving plate 6 rotates, the guide grooves 15
．． 15a and 16.16a.

Reference numeral 18 denotes an annular groove having a semicircular cross section, which is formed in the second moving plate 6 on the opposite side from the guide groove 16, and has an outer diameter commensurate with the eccentric weight based on the guide grooves 15.15a and 16.16a. However, a plurality of them are provided in the circumferential direction. Reference numeral 19 denotes an annular groove similar to that described above, which is formed in the adjustment plate 12 in correspondence with the annular groove 18 of the second moving plate 6. A steel ball 20 is disposed across the annular WA 18, 19 of the second moving plate 6 and the adjusting plate 12.

Now, when the above configuration is applied to a transportation robot,
An electric motor (not shown) is connected to the input part of the eccentric shaft 8, and a conveying arm (not shown) is attached to the output shaft 14. When the electric motor is driven, the eccentric shaft 8 rotates, and eccentric rotational force is transmitted to the second moving plate 6 by the eccentric portion 8a.

The second moving plate 6 that has received this eccentric rotational force is in a state where the guide groove 16.16a is always in contact with the guide groove 15.15a of the first moving plate 4 via the rolling ball 17, as shown in FIG. It is displaced and rotated around the eccentric portion 8a of the eccentric shaft 8.

This movement of the second moving plate 6 causes the steel ball 20 to roll along the inner grooves 18 and 19 of the second moving plate 6 and the adjusting plate 12, and the eccentric rotational force of the second moving plate 4ft6 is generated. Only the rotational force of the second moving plate 6 that is absorbed and eliminated is transmitted to the adjusting plate 12 by the steel balls 20, thereby rotating the output shaft 14 and moving the arm.

In this case, the amount of one rotation of the eccentric shaft 8 is equal to the amount of rotation of the rolling ball 17.1
Since 7a corresponds to the amount by which the guide grooves 15.15a and 16.16a are moved by the length dimension corresponding to 2 wave numbers, the reduction ratio is generally equal to the number 2 and the wave number N of the guide grooves of the first moving plate. 2
The ratio is 2/N+2. In the above embodiment, the wave number N of the guide groove 15 is 10, so the reduction ratio is 2/10+2=1/6.

In this way, while ensuring a relatively high reduction ratio of 1/6, the first moving plate 4 and the second moving plate 6 only need to be arranged side by side facing each other, so they are short in the left and right direction. It has a thin and thin design, making the entire device smaller and more compact.

Further, the first moving plate 4 and the second moving plate 6 are connected to the rolling balls 17 via these guide grooves 15.15a and 16.16a.
．． 17a, play between the first and second moving plates 4.6 can be eliminated, and the rotation angle of the output shaft 14 can be detected with high accuracy.

In addition, the first moving plate 4 and the second moving plate 6 allow the rolling ball 1 to pass through these guide grooves 15.15a and 16.16a.
7.17a, so moving plate 4.
The rolling balls 17.17a are connected to the guide grooves 15.15a and 16.16a, while the rolling balls 17.17a are substantially integral with each other and have high rigidity.
In addition, since they are arranged in close contact without rattling, play such as backlash is of course eliminated, and the engagement ratio is increased.

Furthermore, since the first and second moving plates 4.6 themselves can be relatively thin, their inertial force is reduced and controllability is improved.

In addition, the guide grooves 15.15a and 16.16a and the rolling ball 17.17a are ll! Since the friction is small, the rotational force can be reduced efficiently and there is little power loss. Moreover, the first and second moving plates 4.6 are connected by the guide grooves 15.15a and 16.16a via the ball 17.17a, and the number of parts involved in rotation transmission increases. The transmission torque of the second moving plate 6 to the plate 4 increases.

Next, FIG. 5 and FIG. 6 show a second embodiment of the present invention, and in this second embodiment, the steel ball 2 of the first embodiment is
Bin 21 is used instead of 0.

That is, instead of the annular groove 19, a bottle 21 is vertically protruded from the adjusting plate 22, and a circular differential gear which receives the bottle 21 instead of the annular groove 18 is installed on the second moving plate 23. A recess 24 is formed. In this state, movement of the bin 21 is allowed within the diametric range of the differential recess 24 by an amount of eccentricity m related to the guide groove of the moving plate.

Further, FIG. 7 shows a third embodiment of the present invention, and in this third embodiment, the first moving plate 4 and the adjusting plate 12 of the first embodiment are arranged oppositely to each other. For this purpose, the adjusting plate 25 is provided with a through hole 26 through which the eccentric shaft 8 is inserted, and the second moving plate 27 is made non-porous, and an exit shaft 28 is connected to the center thereof.

Furthermore, FIG. 8 shows a fourth embodiment of the present invention, in which guide grooves are provided in the second moving plate 29 and the adjusting plate 30 in place of the annular grooves 18 and 19 of the first embodiment. 31.31a
and 32.32a, and a rolling ball 33.33a is provided in place of the steel ball 20.

As a result, the rotational force from the eccentric shaft 8 is transmitted between the first moving plate 4 and the second moving plate 29 in a decelerated state, and also between the second moving plate 29 and the adjusting plate 30. The speed is further reduced and transmitted to the adjustment plate 30.

The same effects as in the first embodiment can be obtained even if the configurations are as in the second to fourth embodiments. In each of the above embodiments, the same members are given the same reference numerals, and only different parts are explained.

Next, FIG. 9 shows an annular cage or chainer 34 that holds the rolling balls 17 in position.
Holding holes 35.35a holding rolling balls 17.17a are formed in the circumferential direction of the holding holes 34, respectively. This makes it easier to attach the rolling ball 17. In this case, a chainer may be used for the steel ball 20 as well, similar to the above.

Next, FIGS. 10 to 12 show a fifth embodiment of the present invention, and in this fifth embodiment, the guide groove 1 of the first moving plate 4 is
5. An annular convex portion 100 is provided in place of 15a.

The inner peripheral surface of this convex portion 100 is a wavy guide surface 100a approximated by an epicycloid curved surface, and the outer peripheral surface is a wavy guide surface 100b approximated by an epitrochoid curved surface.

On the other hand, a medium-sized circumferential groove 200 is formed in the first moving plate 6 instead of the guide groove 16.16a, and the inner circumferential surface of this circumferential groove 200 is a hypotrochoid curved guide wall 200b. A rolling ball 17 as shown in FIG. 11 is disposed in contact between the guide wall 200a and the guide surface 100a, and a rolling ball 17a is arranged between the guide wall 200b and the guide surface 100a. placed in contact.

In these conditions, the rolling balls 17.17a are on the guide surface 10.
0a, 100b and the guide walls 200a, 200b are in two-point contact with each other as shown in FIG.
The slippage of the moving plate 4.6 is reduced and the torque transmitted between the first and second moving plates 4.6 is increased.

In each of the above embodiments, the guide groove and the annular groove are formed to have a semicircular cross section, but it is needless to say that the guide groove or the annular groove is formed to have a semicircular cross section. The rolling ball or the steel ball may be arranged in dotted line contact with the guide groove or annular groove. In general, these balls may be formed from a highly wear-resistant material such as ceramic.

In addition, the number of concentrically located guide grooves is not limited to two, but can be set to three or four, and various changes can be made without departing from the gist of the invention.

[Effects of the Invention] As described above, according to the present invention, it is possible to achieve miniaturization while ensuring a relatively high reduction ratio, the movement position can be set with high accuracy without play such as backlash, and the inertia is small. It is ideal as a transmission because it is easy to control, requires only force, has a high engagement ratio, has high overall rigidity, low friction, and little power loss, and has more parts involved in rotation transmission, increasing transmitted torque. effect can be obtained.

[Brief explanation of the drawing]

1 to 4 show a first embodiment of the present invention;
The figure is a vertical sectional view of the whole, Figure 2 is an exploded perspective view of the whole, and Figure 3 is a longitudinal sectional view of the whole.
The figure is an explanatory diagram of the shape of the guide groove, and Fig. 4 is an explanatory diagram of the action.
5 and 6 are views corresponding to FIG. 1 and 2 showing a second embodiment of the present invention, and FIG. 7 is a view corresponding to a third embodiment of the present invention, with the case removed. FIG. 8 is a diagram equivalent to FIG. 1, and FIG. 8 is a diagram equivalent to FIG. 7 showing a fourth embodiment of the present invention.
FIG. 9 is a perspective view of the beam chainer, FIG. 10 is an exploded perspective view of the fifth embodiment, FIG. 11 is an overall longitudinal sectional view, and FIG. 12 is an enlarged longitudinal sectional view of the main parts.

Claims (1)

[Claims] 1) (a) first and second moving plates arranged to face each other; (b) a plurality of concentric circles on the opposing surface of one of the first and second moving plates; a wave-shaped guide groove continuously formed along the circumference of the shape, and a wave-shaped guide groove formed concentrically opposite the guide groove on the other side; (c) the first and second wave-shaped guide grooves; The first moving plate is disposed between the moving plates and extends within these mutually opposing guide grooves, and as the first moving plate rotates with respect to the second moving plate, the first moving plate rolls along the guide groove. A rolling ball type differential transmission mechanism comprising a rolling ball that changes the rotation of a moving plate. 2) Two guide grooves are formed in each of the first and second moving plates, and the guide grooves of the first moving plate have an epicycloid curve and an epitrochoid curve, and the other guide groove has a hypocycloid curve and an epitrochoid curve. The rolling ball type differential transmission mechanism according to claim 1, characterized in that it has a hypotrochoidal curve.