JPS6329145B2 - - Google Patents

Description

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

An example in which a conventional power transmission device of this kind is used as a speed reducer is shown in FIGS. 1 and 2. In both figures, 1 is a sun roller directly connected to an input shaft 8 that is rotationally driven, and 3 is a sun roller fixed to a case 10. inner roller, 2
A plurality of (three in this case) planetary rollers are rotatably supported by a planetary pin 5 fixed to a carrier 6 via a bearing 4.

The sun roller 1, the plurality of planetary rollers 2, and the inner roller 3 apply a pressing force P to these rollers in the radial direction.
Power is transmitted by the frictional force U generated by the pressure contact.

That is, in this case, the inner diameter Di of the inner roller 3 is the sum of twice the outer diameter Ds of the sun roller 1 and the outer diameter Dp of the planetary roller 2 (that is, Ds+
2Dp), and the above-mentioned pressing force P is generated by elastically deforming these rollers and pressing them together. In this case, there are the following problems.

(1) The above pressure contact force P is the interference between the inner roller 3, planetary roller 2, and sun roller 1: δ=(Ds+
2Dp) - varies significantly depending on Di. For this reason,
The frictional force U required to transmit power is also the pressure contact force P
Therefore, in order to obtain the expected frictional force U, the contact diameters Di, Dp, and
Each dimension of Ds must be precisely finished to accurately set the interference margin δ. This significantly increases the manufacturing cost of the device.

(2) Furthermore, if there is a manufacturing error in each roller, the interference δ will also fluctuate due to the manufacturing error, and the friction force U will correspondingly become unstable.

For this reason, reliability as a power transmission device decreases.

(3) When assembling the device, it is necessary to create gaps between each roller that are essential for assembly by heating (expanding) the inner roller 3 or cooling (contracting) the planetary roller 2 or sun roller 1. Therefore, it takes a lot of effort to assemble.

(4) Furthermore, when disassembling the product, it must be done while the pressure contact force P is still applied.
This results in significant damage to the contact surfaces of each roller, since relatively high axial extraction forces are required.

(5) Sun roller 1, planetary roller 2, inner roller 3,
The carrier 6 is supported by the casing 10 directly or indirectly via a bearing.

Therefore, if there is a machining error in the casing 10, each pressure contact surface may make uneven contact.

This reduces the durability of the device.

The present invention has been made in view of the above, and it is an object of the present invention to provide a planetary roller type power transmission device that is easy to assemble and disassemble, is inexpensive to manufacture, provides uniform pressing force, and is highly durable.

1 of the present invention with reference to FIGS. 3 to 5.
An example will be explained. In Fig. 3, 1 is a sun roller, 2 is a plurality of planetary rollers, 4 is a needle bearing, 5 is a planetary pin, 6 is a carrier, 8 is an input shaft, 10 is a casing, 11 is an output shaft, and 13 is an input shaft. 8 is a bearing for supporting the output shaft 11; 14 is the output shaft 11;
These bearings are used to support the bearings, and their configuration is the same as that of conventional bearings. Reference numeral 30 denotes an inner roller, that is, an elastic roller, which is made of an elastic member such as a special steel material having toughness. As shown in FIG. 4, the inner rollers 30 are formed into two thin-walled cylindrical portions 30a having contact surfaces 30d with the planetary rollers 2, separated in the axial direction of the rotation shafts such as the input shaft 8 and the output shaft 11. a thick-walled cylindrical portion 30b; a thin-walled disk portion 30c connecting both ends of the thin-walled cylindrical portion 30a and each thick-walled cylindrical portion 30b;
It consists of combining. The two thick-walled cylindrical portions 30b are formed relatively thick in the axial direction of the rotating shaft, and the wall thickness t2 of the thin-walled cylindrical portion 30a is the same as the thick-walled cylindrical portion 30b.
It is formed to have a thin wall, for example, 1/2 or less of the wall thickness t1.
Further, the thickness of the thin disk portion 30C is set to the above-mentioned thickness t2.
The wall thickness is equal to or slightly thicker than that of the cylindrical part 30b (much thinner than the cylindrical part 30b), and as shown in FIG. This prevents the roller 30 from deforming outward when the cylindrical portion 30b is pressed with a pressing force T as shown in FIG. 4b.

Also, the inner diameter Di of the inner roller 30 in the free state
is formed to be slightly larger than the sum of twice the outer diameter Ds of the sun roller 1 and the outer diameter Dp of the planetary roller 2, ie (Ds+2Dp), to facilitate assembly and disassembly of the planetary roller 2.

When assembling the power transmission device having the above configuration, after assembling the sun roller 1 and the planetary rollers 2 into the casing 10, the inner roller 30 is inserted in a free state and fixed with the pin 9. In this case, since a slight gap is formed between the inner circumference of the inner roller 30 and the outer circumference of the planetary roller 2 as described above, the inner roller 30 can be inserted very easily. Inner roller 3
0, place a shim 15 of an appropriate thickness between the side surface of the thick cylindrical portion 30b of the inner roller 30 and the case cover 16, tighten the bolts 12, and remove the case cover 1.
6 is fixed to the casing 10. Due to the tightening described above, the inner roller 30 receives a pressing force T in the axial direction as shown in FIG. 3, and the total width Wi in the free state is reduced to Wt.

Due to this reduction in the overall width Wi, the inner diameter Di also tends to be reduced, but after the contact surface 30d contacts the outer periphery of the planetary roller 2, the deformation in the radial direction is restrained, and a pressure contact force P corresponding to this restraint is generated. The pressing force P causes the inner roller 30, the planetary roller 2, and the sun roller 1 to
are pressed together. That is, as shown in FIG. 4, when the inner roller 30 is compressed from the free state with the pressing force T,
As the overall width Wi decreases to Wt, the width Bi of the contact surface 30d decreases to Bt, and the inclination angle θi decreases to θt, the inner diameter Di decreases.
Dm, and a crowning c with a radius of curvature r is formed on the contact surface 30d as shown in FIG. 4b.

Therefore, for example, the inner diameter Di=Ds+ in the free state
When the inner roller 30 formed to 2Dp is assembled in the casing 10 and compressed by the pressing force T, the crowning C (C in Fig. 4) is first compressed, and then the effective deformation amount e is compressed, and eventually The amount of compression of the inner roller 30 is (C+e), and a pressing force P corresponding to (C+e) is generated. FIG. 5 shows the relationship between the pressing force T and the amount of radial deformation E of the inner roller 30. As is clear from FIG. 5, the amount of deformation E is proportional to the pressing force T, and therefore the pressing force P is also proportional to the pressing force T, and furthermore, to the thickness of the shim 15. By changing the thickness and changing the total width Wt of the inner roller 30, that is, by changing the crowning amount C and the effective deformation amount e, the pressing force P can be easily adjusted.

FIG. 6 shows another embodiment of the present invention, in which the sun roller 100 is formed of an elastic roller similar to that of FIG. The pressing force T is adjusted by changing the . 3 is an inner roller fixed to the casing 10, 80 is an input shaft, and the sun roller 100 is fixed to the input shaft 80. The other configurations are the same as in the first embodiment.
In the case of this embodiment, tighten nut 19 and use the full width
When Wt is reduced, the outer diameter Ds of the sun roller 100 becomes
is about to increase, but due to the planetary roller 2, the outer diameter
The increase in Ds is restrained, and a pressing force P corresponding to this restraint is generated. The pressing force P is proportional to the amount by which the nut 19 is tightened.

FIG. 7 shows still another embodiment of the present invention, in which a planetary roller 200 is formed of an elastic roller similar to that of FIG. Tightening bolts 18 are provided at equal intervals in the circumferential direction on the thick cylindrical portion of the roller 200, and the pressing force T is adjusted by changing the tightening amount of the nuts 17.

That is, when the nut 17 is tightened to reduce the total width Wt of the planetary roller 200, the expansion of the diameter Dp is restrained, and a pressing force P corresponding to this restraint is generated. 1 is a sun roller fixed to the input shaft 8, and 3 is an inner roller fixed to the casing 10. The other configurations are the same as in the first embodiment.

FIG. 8 shows a case where the inner roller 30 made of an elastic member is formed in a double row type (two rows in this embodiment), and shows the shapes of the thin cylindrical portion 30a, the thick cylindrical portion 30b, and the thin disk portion 30C, and The binding mode is the fourth
This is the same as the case shown in the figure. In the figure, 2 indicates a planetary roller.

FIG. 9 shows the case where the sun roller 100 is a double row type elastic roller, 100a is a thin cylindrical part, 1
00b is a thick-walled cylindrical portion, and 100c is a thin-walled disk portion, and the shape and manner of connection of these elements are the same as in the case of FIG. 100d is a contact surface with the planetary roller 2.

Incidentally, although not shown, it is of course possible to form the planetary rollers in a double-row type as in FIG. 9. Further, in each of the above embodiments, any one of the sun roller, planetary roller, and inner roller is an elastic roller, but a part or all of the rollers may be an elastic roller.

As described above, the power transmission device according to the present invention includes a plurality of thick-walled cylindrical portions and thick-walled cylindrical portions formed by dividing all or part of the sun roller, planetary roller, and inner roller in the axial direction of the rotating shaft. It consists of a thin cylindrical part that is thinner than the cylindrical part and has a contact surface with the mating roller, and a plurality of thin disc parts that individually connect both ends of the thin cylindrical part and the thick cylindrical part. Since the elastic roller is formed so that the diameter of the thin cylindrical part changes when both ends of the part are pressed, there are the following advantages.

(1) As each roller can be assembled and disassembled with a small gap in the radial direction between the sun roller, planetary roller, and inner roller, there is no risk of damaging the surface of each roller during assembly or disassembly. There is no. Therefore, the durability of each roller is improved and assembly is easier. Decomposition is extremely easy.

(2) Pressure force can be applied between each roller simply by pressing both ends of the thick cylindrical part of the elastic roller in the axial direction of the rotating shaft, and by changing the width of the elastic roller using shims, etc. The magnitude of the pressing force can be adjusted. Therefore, the pressure contact force can be adjusted very easily, and even if there are manufacturing errors in each roller, a uniform and accurate pressure contact force can be obtained. That is, it is possible to obtain a uniform and accurate pressing force without increasing the machining accuracy of each roller, thereby reducing the manufacturing cost of the device.

(3) Since the contact part of the elastic roller with other rollers is formed with a thin wall, this part has a large deformability and even if the rollers try to make uneven contact due to processing errors of the casing etc., the thin part will not cause strong contact. By absorbing this, uneven hitting can be prevented. Therefore, the durability of the device is improved.

(4) All or part of each roller is arranged such that a thin cylindrical part is placed at the contact part with the mating roller and a thick cylindrical part is arranged on the opposite side of the contact part, and the thin cylindrical part and the thick cylindrical part are connected to each other. An elastic roller is formed by joining together at a disk portion, and the elastic roller is applied with a pressing force to the side end face of a thick cylindrical portion with high rigidity, and a mating roller is applied to a thin cylindrical portion with high deformability. When the elastic roller is pressed in the axial direction, the neutral surface (the surface that does not move in the radial direction) moves away from the contact surface (in the case of an inner roller, it moves toward the outer periphery). direction). Therefore, there is almost no change in the diameter of the thick cylindrical part due to the pressing force, and almost all of the pressing force is due to the change in the diameter of the contact surface (in the case of an inner roller, the amount of reduction in the inner diameter), that is, the pressing force is converted into an increase in Therefore, a large pressing force can be obtained with a small pressing force compared to the conventional one.

(5) Since both side plate surfaces of the thin-walled circular plate connecting the thin-walled cylinder to the thick-walled cylinder are inclined, the axial pressing force applied to the thick-walled cylinder is effectively applied to the thin-walled cylinder. This allows the thin cylindrical portion to reliably undergo crowning deformation.

[Brief explanation of the drawing]

Figures 1 and 2 show an example of a conventional planetary roller speed reducer. Figure 1 is a sectional view taken along the axis of the rotating shaft, and Figure 2 is a sectional view taken along line A-A in Figure 1. It is. 3 to 5 show one embodiment of the present invention, FIG. 3 is a sectional view along the axis of the rotating shaft, FIG. 4 is a sectional view showing the shape of the elastic roller, and FIG. 5 is a sectional view of the pressing force. It is a line diagram showing a change. 6 to 9 show other embodiments of the present invention, FIGS. 6 and 7 are views corresponding to FIG. 3, and FIGS. 8 and 9 are cross sections showing one example of the elastic roller. It is a diagram. 1,100...Sun roller, 2,200...Planet roller, 3,30...Inner roller, 6...Carrier, 8,80...Input shaft, 10...Casing,
11...Output shaft, 15...Shim.

Claims (1)

[Claims] 1. By pivotally supporting a plurality of planetary rollers that are in contact with the outer periphery of a sun roller connected to a rotating shaft and the inner periphery of an inner roller fixed to a stationary member, respectively, with a carrier connected to a rotating shaft. , in which power is transmitted between the two rotating shafts, all or part of the sun roller, planetary roller, and inner roller are divided in the axial direction of the rotating shaft, and a pressing force is applied. a plurality of thick-walled cylindrical portions having side end surfaces that are shaped like the above-mentioned thin-walled cylindrical portions, a thin-walled cylindrical portion that is formed thinner than the thick-walled cylindrical portions and has one of its inner and outer circumferential surfaces as an abutting surface with a mating roller; The shaft center is formed thinner than the thick cylindrical portion, and both ends of the thin cylindrical portion are individually connected to the thick cylindrical portion, and the width between the two plate surfaces becomes narrower as it approaches the contact surface. It consists of a thin disk part inclined at a certain angle with respect to a plane perpendicular to the line, and is constituted by an elastic roller that changes the diameter of the thin cylinder part when pressing both end surfaces of the thick cylinder part. Features a planetary roller type power transmission device.