JPS6124749Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in a planetary roller type power transmission device that transmits power by the frictional force of rollers that are in contact with each other.

A plurality of planetary rollers are circumscribed around the circumferential surface of the sun roller, and an inner roller fixed to the casing is held on the outside of the planetary rollers, and the revolution speed of the planetary roller is set as the output shaft when the sun roller is used as the input shaft. A conventional planetary roller type speed reducer of the removable type is shown in FIG.

In FIG. 1, a sun roller 2 is connected to an end of an input shaft 1, and a planet roller 7 is rotatably connected to a plurality of planet pins 5 fixed to a carrier 4 of an output shaft 3 via a needle bearing 6, respectively. is supported in contact with the outer peripheral surface of the sun roller 1, and an inner roller 9 is fixed to the casing 8 with its inner peripheral surface in contact with the outer peripheral surface of the planetary roller 7. 10 is a bearing that supports the input shaft 1; 11 is the output shaft 3;
This is a bearing that supports the

In this device, the inner roller 9 is an elastic roller made of an elastic member such as a special steel material having toughness, and as shown in FIG. , a thick-walled cylindrical portion 9b formed into two parts separated in the axial direction of the rotation shaft such as the input shaft 1 and the output shaft 3, and the thin-walled cylindrical portion 9.
It is constructed by combining thin-walled cylindrical portions 9c that connect both side ends of a and the individual thick-walled cylindrical portions 9b. The two thick-walled cylindrical portions 9b are formed to be relatively thick in the axial direction of the rotating shafts 1 and 3, and the wall thickness t2 of the thin-walled cylindrical portion 9a is, for example, about 1/ of the wall thickness t1 of the thin-walled cylindrical portion 9b. 2
Formed with a thin wall of: Further, the thin disk portion 9c has a wall thickness t3 equal to or slightly thicker than the wall thickness t2 of the thin cylindrical portion 9a (much thinner than the wall thickness t1 of the thick cylindrical portion 9b).

That is, in the inner roller 9, the thick cylindrical portion 9b is formed to have more rigidity than the thin cylindrical portion 9a and the thin disk portion 9c.

In addition, the inner diameter D1 of the inner roller 9 in the free state is
Outer diameter DS of sun roller 2 and outer diameter Dp of planetary roller 7
, that is, (Ds+2Dp), to facilitate assembly and disassembly of the planetary roller 7.

To assemble the power transmission device having the above configuration, after assembling the sun roller 2 and the planetary rollers 7 into the casing 8, the inner roller 9 is inserted in a free state and fixed to the casing 8 side with a pin 12. In this case, since a slight gap is formed between the inner circumferential surface of the inner roller 9 and the outer circumferential surface of the planetary roller 7 as described above, the inner roller 9 can be inserted very easily. After inserting the inner roller 9, a shim 14 of an appropriate thickness is placed between the side surface of the thick cylindrical portion 9 of the inner roller 9 and the case cover 13 to generate an axial pressing force T, which will be described later. 15 to secure the case cover 13 to the casing 8. By tightening the bolt 15, the inner roller 9 is subjected to an axial pressing force T corresponding to the thickness of the shim 14, as shown in FIG. 2b, and the total width Wi in the free state is reduced to Wt. be done. This reduction in the overall width Wi also tends to reduce the inner diameter Di, but after the contact surface 9d contacts the outer peripheral surface of the planetary roller 7, the deformation in the radial direction is restrained, and the pressure contact force P corresponding to this restraint is reduced. The pressure force P causes the inner roller 9 to
and the planetary roller 7, and the planetary roller 7 and the sun roller 2 are pressed against each other. That is, as shown in Fig. 2 a and b,
When the inner roller 9 is compressed from the free state by the pressing force T, its total width Wi decreases to Wt, and as a result, a crowning deformation with a radius r is formed on the contact surface 9d of the inner roller 9 with the planetary roller. Due to inner diameter
Di is reduced to Dm. This crowning deformation amount e is restrained by the planetary roller 7, thereby generating the pressing force P. however,
The conventional planetary roller type power transmission device described above has the following drawbacks.

With respect to the thickness of the shim 14, an axial pressing force T acts on both sides of the inner roller 9, and its entire width is elastically deformed from Wi to Wt, but at this time, as shown in FIG. Both sides of the roller 9 have an inclination of θ corresponding to the amount by which the total width decreases from Wi to Wt. For this reason, both sides of the inner roller 9 and the casing 8
And at the contact parts a ₁ and a ₂ with the case cover 13,
The axial pressing force T is supported in a point contact state (line contact on the circumference). Therefore, the inner roller 9 is worn out or worn out in the _A1 part, and the shim 14 is worn out in the _A2 part. As a result, the total width Wt of the inner roller 9 increases during operation, and the axial pressing force T decreases accordingly, leading to a shortage of the roller pressing force P necessary for power transmission. This may make it impossible to transmit power during operation or result in a reduction in power transmission capacity.

One embodiment of the present invention will be described below with reference to FIGS. 1, 4, and 5. Reference numeral 91 is an elastic inner roller made of an elastic member such as a special steel material having toughness. The inner roller 91 has a thin cylindrical portion 91
a, a U-shaped elastic roller formed of two thick-walled cylindrical portions 91b and a thin-walled disk portion that individually connects both ends of the thin-walled cylindrical portion 91a and the inner peripheral end of the thick-walled cylindrical portion 91b; be. Thickness of the thin cylindrical portion 91a
t ₂ is, for example, 1/2 of the maximum wall thickness t ₁ of the thick-walled cylindrical portion 91b.
The thickness t ₃ of the thin disk portion 91c is thicker than the thin cylindrical portion 91a, but is sufficiently thinner than the thick cylindrical portion 91b.

Furthermore, both end surfaces 91b ₁ of the thick-walled cylindrical portion 91b, that is, the contact surfaces with the casing 8 and the shim 14 shown in FIG. curved surface).

When assembling the inner roller 91, as shown in FIG _.
After contacting the casing 8 and the shim 14, the bolts 15 of the case cover 13 are tightened. As a result, an axial pressing force T is generated and the inner roller 91
The total width Wi in the free state is reduced to WT corresponding to the thickness of the shim 14, and the planetary roller 7 (see Fig. 1)
The inner circumferential surface 91a ₁ of the thin cylindrical portion 91a that comes into contact with the cylindrical portion 91a attempts to undergo crowning deformation with a radius r. As this crowning deformation is restrained by the planetary roller 7, a pressure contact force P is generated between the inner roller 91 and the planetary roller 7 and between the planetary roller 7 and the sun roller 2. At this time, the inner roller 91
Since both side end surfaces 91b ₁ are formed into convex curved surfaces, the side end surfaces 91b ₁ , the casing 8 and the shim 14
There is no occurrence of a strong contact between the side end surface 91 and
b Since the contact area of ₁ becomes wider, the contact surface pressure will not become excessive.

The above is an example in which the present invention is applied when the inner roller is an elastic roller, but the same function can be obtained even if the present invention is applied using the sun roller or the planetary roller as an elastic roller.

FIG. 6 shows another embodiment in which the present invention is applied when the sun roller is an elastic roller.
Similar to the inner roller 91 shown in the figure, both side end surfaces 21b ₁
The thick cylindrical part 21b is formed into a curved shape, the thin cylindrical part 21a whose outer peripheral surface becomes the contact surface 21d with the planetary roller 7, the thick cylindrical part 21b and the thin cylindrical part 2.
A sun roller 21 made of an elastic material and a thin disk portion 21c connecting the sun roller 1a and the rotary shaft at right angles to the axial direction of the rotating shaft.
is attached to the end of the input shaft 1, and its thick cylindrical part 2
On the side of 1b is a nut 1 screwed into the input shaft 1.
6 is brought into contact with the sun roller 21, and the total width ws of the sun roller 21 is changed by the tightening amount of the nut 16 to adjust the pressing force T. Reference numeral 90 denotes an inner roller, and the rest of the structure is the same as that shown in FIG. In this embodiment, when the nut 16 is tightened to reduce the overall width Ws, the outer diameter Ds of the sun roller 21 tends to increase, but the planetary roller 7 restricts the increase in the outer diameter Ds, and the amount corresponds to this restriction. pressure contact force P
occurs. The pressing force P is proportional to the amount by which the nut 16 is tightened.

The present invention is constructed as described above, and according to the present invention, both end surfaces of the thick cylindrical portion of the U-shaped elastic roller are formed into curved surfaces, so that the pressing members such as the casing and shims and the elastic roller Since the contact area between the two increases as the axial pressing force increases, the surface pressure on the contact surface does not become excessive. Therefore, it is possible to prevent the occurrence of fatigue on the contact surface of the elastic roller, fraying of the shim, etc., as well as a decrease in the pressing force during operation.

[Brief explanation of the drawing]

Figures 1 to 3 show an example of a conventional planetary roller speed reducer. Figure 1 is a sectional view along the axis of the rotating shaft, and Figures 2 and 3 are explanatory diagrams of the action of elastic rollers. It is. 4 and 5 show one embodiment of the present invention, FIG. 4 is a sectional view of the elastic roller, and FIG. 5 is a view of the elastic roller being installed. FIG. 6 is a diagram corresponding to FIG. 1 showing another embodiment of the present invention. 2, 21...Sun roller, 4...Carrier, 7
... Planetary roller, 91 ... Inner roller, 91a, 2
1a... Thin cylindrical part, 91b, 21b... Thick cylindrical part, 91c, 21c... Thin disc part, 91b ₁ ,
21b ₁ ...Side end surface.

Claims (1)

[Scope of utility model registration request] A plurality of planetary rollers pivotally supported by a carrier connected to the rotating shaft are arranged between the outer periphery of the sun roller connected to the rotating shaft and the inner periphery of the inner roller, the above-mentioned sun roller, A plurality of thick-walled cylindrical portions formed by dividing all or part of the planetary roller and the inner roller in the axial direction of the rotating shaft, and a thin-walled cylindrical portion on which a contact surface with the mating roller is formed; It consists of a thin cylindrical part connecting a thin cylindrical part and the thick cylindrical part, and both end surfaces of the thick cylindrical part, which are in contact with a holding member such as a case, are formed into curved surfaces convex toward the holding member. A planetary roller type power transmission device characterized by forming a U-shaped elastic roller.