JPS6116865B2 - - Google Patents

Description

[Detailed Description of the Invention] [Technical Field] The present invention relates to a speed reducer, and more particularly, to a speed reducer that uses a planetary mechanism and transmits power through rolling contact between rollers rather than meshing gears. be.

[Background technology]

Planetary mechanisms have a relatively large reduction ratio and are capable of transmitting large amounts of power, but
In order to address the problems with this, such as the fact that only a predetermined reduction ratio can be obtained and the noise, a system in which power is transmitted by rolling contact using rollers has been proposed in recent years. In this case, the noise level is extremely low, and the reduction ratio has the advantage of being able to be set quite freely as there is no restriction on the number of teeth. It has also been proposed to obtain an output with a large reduction ratio by arranging planetary rollers with different diameters in the axial direction and using a differential that utilizes the difference in diameter of these planetary rollers. However, in the device disclosed in this publication, a stepped cylinder fixed with a key is provided on the outer peripheral surface of the input shaft, and the outer peripheral surface of the cylinder is used as the contact surface of a large-diameter planetary roller. The sun roller is constructed by disposing another cylindrical body freely rotatably on the outer circumferential surface of the part where the diameter is reduced through a needle roller bearing, and using the outer circumferential surface of this other cylindrical body as the contact surface of the small-diameter planetary roller. However, the processing and fabrication of the sun roller part is complicated, and transmission torque loss occurs in the sun roller part.

[Purpose of the invention]

The present invention has been made in view of these points, and its object is to provide a speed reducer in which the structure of the sun roller portion is simple, easy to process, and with little transmission torque loss.

[Disclosure of the invention]

Therefore, the present invention provides a straight input shaft having a cylindrical shape with a single diameter, a plurality of planetary rollers having different diameters that are coaxially arranged side by side in the axial direction and rotate together, and planetary rollers. A large diameter planetary roller, a small diameter planetary roller, and a boss with the same diameter as the largest diameter planetary roller are integrally formed between the largest diameter planetary roller and the boss. Small-diameter planetary rollers are provided, and the input shaft is in pressure contact with the outer circumferential surface of the input shaft so that the planetary roller of the largest diameter and the boss can freely roll on the outer circumferential surface of the input shaft, and at least one of the planetary rollers is provided with an output means. The planetary roller with the largest diameter and the boss with the same diameter are in direct contact with the input shaft.

The present invention will be described in detail below based on the illustrated embodiment. In the figure, 1 is an input shaft as a sun roller. A shaft portion 3 at both ends is inserted into a radial groove 21 provided in a carrier 2 that can freely rotate relative to the shaft portion 1.
1 is supported, a plurality of planetary rollers 3 are arranged at equal intervals around the axis. Each planetary roller 3 is formed integrally and coaxially with three planetary rollers 32, 33, and a boss 34 arranged in the axial direction and having different diameters. A boss 34 has a diameter, and between them is a planetary roller 33 having an outer diameter smaller than both. The input shaft 1 is attached to the outer periphery of the planetary roller 32.
A ring 4 is disposed coaxially with the input shaft 1 , and a ring 5 having an inner diameter smaller than the ring 4 is disposed coaxially with the input shaft 1 on the outer periphery of the planetary roller 33 . Output connecting rings 6, 7 whose outer peripheral surfaces are shaped like gears are further disposed on the outer peripheries of these rings 4, 5, and one end of each output connecting ring 6, 7 is provided with a disc-shaped shaft, which is connected to the shaft of the planetary roller 3. Operators 8 are screwed to cover both ends in the direction. Both rings 4 and 5 are each formed of a spring material having a U-shaped cross section with an opening width wider than the bottom width, and as shown in FIG. , 7, and is compressed in the axial direction by screwing the operator 8, thereby reducing the inner diameter. For this purpose, the ring 4 is brought into pressure contact with the planetary roller 32 and the planetary roller 32 and the boss 34 are brought into pressure contact with the input shaft 1, and the ring 5 is also brought into pressure contact with the planetary roller 33. Since this contact pressure P is proportional to the amount of axial displacement of the rings 4 and 5 due to the axial movement of the operator 8, it can be easily adjusted. The contact pressure P can be determined according to the allowable output torque.

Furthermore, the planetary rollers 32 and the bosses 34, which are larger in diameter than the planetary rollers 33 and have the same diameter, are located at the front and rear of the planetary rollers 33 in the axial direction and are in pressure contact with the input shaft 1. Since the axes of the planetary rollers 3 are kept parallel, the planetary rollers 3 are not tilted and skewing is prevented, and therefore the rotation of the planetary rollers 3 is smooth. The input shaft 1 as a whole is supported by a rotatable cantilever or both sides as shown in FIG.

In this planetary reducer configured as described above, torque is transmitted by friction via lubricating oil or rolling transmission as a traction drive, and the rotational input from the input shaft 1 is If one ring 4, 5 is fixed so that it cannot rotate, a rotational output with a large reduction ratio, which is a differential output, can be taken out from the other ring 5, 4. To explain this point based on FIG. 4, the diameter of the input shaft 1 is _D1 , the diameter of the planetary roller 32 is _D2 , the diameter of the planetary roller 33 is _D3 , the inner diameter of the ring 4 is _D4 , and the diameter of the ring 5 is D1. Inner diameter
_D5 , a certain line X passing through the center O of the input shaft 1 is the absolute axis, and a certain planetary roller 3 is placed on this absolute axis X.
has its center O ₃ positioned, and one point A on the outer periphery of the planetary roller 32 is in contact with the input shaft, and by rotating the input shaft 1 through an angle θ ₁ , the planetary roller 3 is at the position shown by the imaginary line in the figure. Move to, that is, in the figure
The center O ₃ moves to the position O ₃ ′ and the point A
When ∠O ₃ OO 3 ' moves to point A', ∠O 3 OO ₃ ' is the revolution angle Θ of the planetary roller 3, ∠OO ₃ 'A' is the rotation angle θ ₂ of the planetary roller 3, and rings 4 and 5 are the rotation angle θ 2 of the planetary roller 3.
If the input shaft 1 rotates by angles θ ₄ and θ ₅ from the absolute axis Since it is equal to the rolling contact distance with input shaft 1 at 32, (θ ₁ - Θ) D ₁ /=θ ₂ D ₂ /2 (θ ₁ - Θ) D ₁ = θ ₂ D ₂ ∴Θ=θ ₁ -θ ₂ D ₂ /D ₁ (i) On the other hand, the relationship between the planetary rollers 32, 33 and the rings 4, 5 is such that the rings 4, 5 are dragged by the revolution angle Θ of the planetary rollers 32, 33, and the rings 4, 5 are The planetary roller 3 rotates in the same direction as the revolution of the planetary roller 3.
It is considered that each ring 4 and 5 is sent and rotated in the opposite direction by an amount corresponding to the rotation angle θ _{2 of} the rings 2 and 33. Therefore, θ ₄ D ₄ /2=−ΘD ₄ /2+θ ₂ D ₂ /2 θ ₅ D ₅ /2=-ΘD ₅ /2+θ ₂ D ₃ /2 ∴θ ₄ =-Θ+θ ₂ D ₂ /D ₄ (ii) ∴θ ₅ =-Θ+θ ₂ D ₃ /D ₅ (iii) ) Subtracting equation (iii) from equation (ii), θ ₄ - θ ₅ = θ ₂ (D ₂ /D ₄ -D ₃ /D ₅ ) ∴θ ₂ = (θ ₄ - θ ₅ ) / (D ₂ / _D4 − _D3 / _D5 )
(iv) Substituting equation (i) into equation (ii), θ ₄ =−(θ ₁ −θ ₂ D ₂ /D ₁ )+θ ₂ D ₂ /D ₄ =−θ ₁ +(D ₂ /D ₁ +D ₂ /D ₄ ) θ ₂ Substituting equation (iv) into this, θ ₄ = −θ ₁ + (D ₂ /D ₁ +D ₂ /D ₄ )(θ ₄ −
θ ₅ )/D ₂ /D ₄ −D ₃ /D ₅ (v) Here, if the ring 4 is fixed so as not to rotate, θ ₄ =0, so 0=−θ ₁ (D ₂ /D ₁ +D ₂ /D ₄ )θ ₅ /D ₂ /
D ₄ −D ₃ /D ₅ ∴θ ₅ =−D ₂ /D ₄ −D ₃ /D ₅ /D ₂ /D ₁ +D
₂ /D ₄ θ ₁ (vi) Conversely, when the ring 5 is fixed so as not to rotate, θ ₅ =0, so the above equation (v) is θ ₄ = -θ ₁ +D ₂ /D ₁ +D ₂ / D ₄ /D ₂ /D
₄ - D ₃ /D ₅ θ ₄ θ ₁ = (D ₂ /D ₁ +D ₂ /D ₄ /D ₂ /D ₄ -D
₃ / _D5-1 ) _θ4 = _D2 / _D1 + _D3 / _D5 / _D2 / _D4 - _D3
/D ₅ θ ₄ ∴θ ₄ =D ₂ /D ₄ −D ₃ /D ₅ /D ₂ /D ₁ +D ₃
/D ₅ θ ₁ (vii) By the way, if the rotation of the input shaft 1 is constant, these rotation angles θ ₁ , θ ₄ , and θ ₅ all indicate the rotation angle per unit time, that is, the angular velocity. Therefore, both equations (vi) and (vii) above express the speed ratio of the rings 5 and 4 to the input shaft 1, respectively. And as is clear from both expressions, ring 4
Alternatively, the rotation appearing in the ring 5 is a differential rotation resulting from the difference between the diameters D ₂ and D ₃ of the planetary rollers 32 and 33, and the difference between the inner diameters D ₄ and D ₅ of the rings 4 and 5, and the reduction ratio is Extremely large. Furthermore, two outputs with different large reduction ratios can be selectively extracted depending on which ring 4 or 5 the output is extracted from.

〔Effect of the invention〕

As described above, in the present invention, the input shaft is cylindrical and straight with a single diameter. This is because a boss having the same diameter as the planetary roller and having a small diameter planetary roller positioned between the planetary roller with the largest diameter is brought into pressure contact with the outer circumferential surface of the input shaft, so that the outer circumferential surface of the input shaft can roll freely. Not only does the planetary roller rotate smoothly without any inclination, but the structure of the sun roller section that replaces the sun gear is extremely simplified, making it easy to process and manufacture and provide at low cost. It also has less torque loss and is highly efficient.

[Brief explanation of the drawing]

FIG. 1 is a cutaway perspective view of one embodiment of the present invention, FIG. 2 is a horizontal sectional view of the same, and FIG. 3 is a vertical sectional view of the same.
FIG. 4 is an explanatory diagram of the same operation as above, in which 1 is an input shaft, 4 and 5 are rings, 32 and 33 are planetary rollers,
34 indicates the boss.

Claims (1)

[Claims] 1 A straight cylindrical input shaft with a single diameter, a plurality of planetary rollers with different diameters that are arranged coaxially and in line in the axial direction and rotate together as one, and the planetary rollers are inscribed. Equipped with a ring,
A large-diameter planetary roller, a small-diameter planetary roller, and a boss with the same diameter as the largest-diameter planetary roller are integrally formed, and the small-diameter planetary roller is provided between the largest-diameter planetary roller and the boss. The planetary roller with the largest diameter and the boss are in pressure contact with the outer circumferential surface of the input shaft so that the input shaft can freely roll on the outer circumferential surface of the input shaft.
A speed reducer characterized in that an output means is connected to at least one planetary roller.