JPS6235969Y2 - - 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.

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

The sun roller 1, the plurality of planetary rollers 2, and the inner roller 3 transmit power by a frictional force U generated by pressing these rollers in a radial direction with a pressing force P.

That is, in this case, as shown in FIG. 2, the inner diameter D _i of the inner roller 3 is the sum of twice the outer diameter D _s of the sun roller 1 and the outer diameter D _p of the planetary roller 2 (that is, D _s +
The pressure contact force P is generated by forming the rollers to be slightly smaller than 2D _p ) and assembling them, and by elastically deforming these rollers and pressing them against each other.

However, such conventional devices have 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=(D _s +
2D _p )-D _i . Therefore, the frictional force U necessary for transmitting power also corresponds to the fluctuation of the pressure contact force P, so in order to obtain the expected frictional force U, the contact diameter D of each roller is required.
Each dimension of _i , _Dp , and _Ds must be precisely finished to accurately set the initial tightening allowance δ. This significantly increases the manufacturing cost of the device.

(2) Furthermore, if there is a manufacturing error in each roller, the interference δ also changes due to the manufacturing error, and the frictional force U becomes unstable accordingly.

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

(3) When assembling the device, create a gap between each roller that is essential for assembly by heating (expanding) the inner roller 3 or cooling (contracting) the planetary roller 2 or sun roller 1. This requires a great deal of effort to assemble.

(4) Furthermore, when disassembling the product, it must be done while the pressure contact force P is still applied, which requires a fairly large axial removal force, which causes the contact surface of each roller to be significantly be damaged.

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

For this reason, if there is a machining error in the casing 10, each pressure contact surface may make uneven contact, resulting in a decrease in the durability of the device.

Therefore, as shown in Figures 3 to 5, we developed a planetary roller power transmission device that is easy to assemble and disassemble, has low manufacturing costs, provides uniform contact force, and has improved durability. I can think of things.

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, and 14 is a bearing for supporting the output shaft 11, and these structures are the same as those of the conventional one. 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. The inner roller 30 is connected to the planetary roller 2 as shown in FIG.
A thin cylindrical part 30a having a contact surface 30d with the cylindrical part 30a, a thick cylindrical part 30b formed in two parts separated in the axial direction of the rotation shaft such as the input shaft 8 and the output shaft 11, and both ends of the thin cylindrical part 30a. It is formed by combining thin-walled disk portions 30c that connect individual thick-walled cylindrical portions 30b. 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 1/2 lower than the wall thickness t1 of the thick-walled cylindrical portion 30b. is formed. Further, the thin disk portion 30c has a wall thickness t3 equal to or slightly thicker than the above-mentioned wall thickness t2 (much thinner than the cylindrical portion 30b), and both sides thereof as shown in FIG. 4a. is inclined at θ _i to prevent the inner 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 D _i of the inner roller 30 in the free state
is formed to be slightly larger than the sum of twice the outer diameter D _s of the sun roller 1 and the outer diameter D _p of the planetary roller 2, that is, (D _s +2D _p ), to facilitate assembly and disassembly of the planetary roller 2. ing.

When assembling the power transmission device having the above configuration, the sun roller 1 and the planetary rollers 2 are installed in the casing 10, and then the inner roller 30 is inserted in a free state and fixed with the pin 9. In this case, since a small gap is formed between the inner circumference of the inner roller 30 and the outer circumference of the planetary rollers 2 as described above, the inner roller 30 can be inserted very easily.

After inserting the inner roller 30, a shim 15 of an appropriate thickness is placed between the side surface of the thick cylindrical portion 30b of the inner roller 30 and the casing cover 16, and the casing cover 16 is fixed to the casing 10 by tightening the bolts 12. do. Due to the above tightening, the inner roller 30 is
As shown in the figure, upon receiving the axial pressing force T, the total width W _i in the free state is reduced to W _t .

This reduction in the total width W _i also tends to reduce the inner diameter D _i , but after the contact surface 30 d contacts the outer periphery of the planetary roller 2 , the deformation in the radial direction is restrained, and the pressure contact force P corresponding to this restraint is is generated, and the pressure contact force P causes the inner roller 30, planetary roller 2, and 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,
By reducing the total width W _i to W _t , the width B _i of the contact surface 30d to B _t , and the inclination angle θ _i to θ _t , the inner diameter D _i is reduced to D _n , and the contact surface 30d has a Figure 4b
A crowning c with a radius of curvature r is formed as shown in FIG.

Therefore, for example, the inner diameter in the free state D _i =D _s +
When the inner roller 30 formed in 2D _p is assembled into the casing 10 and compressed with the pressing force T, the crowning c (c in Fig. 4) is first compressed, and then the effective deformation part e is compressed. In the end, the compression amount of the inner roller 30 becomes (c+e), and (c+
A pressing force P corresponding to 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.

In addition, in the case of the device shown in FIG. 6, the sun roller 100 is formed of an elastic roller similar to the _one in FIG. Adjusting T. 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 those of the first embodiment.

In this embodiment, when the nut 19 is tightened to reduce the overall width W _t , the outer diameter D _s of the sun roller 100 tends to increase, but the planetary roller 2 restricts the increase in the outer diameter D _s . A pressing force P corresponding to the constraint is generated. The pressing force P is proportional to the amount by which the nut 19 is tightened.

Furthermore, in the case of the device shown in FIG. 7, the planetary roller 200 is formed of an elastic roller similar to that shown in FIG. Tightening bolts 18 are provided at equal intervals in the circumferential direction, and the pressing force T is adjusted by changing the tightening amount of the nuts 17.

That is, tighten the nut 17 and tighten the planetary roller 200.
When the total width W _t is reduced, the expansion of the diameter D _p 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 those shown in FIGS. 3-5.

As described above, rolling transmission type planetary roller devices using elastic rollers are significantly superior to conventional devices, but there are still improvements to be made in these devices as shown below. .

In other words, rolling transmission systems generally have smaller transmitted power than gear transmissions, and for this reason, for the same transmitted power, rolling transmission systems require larger manufacturing dimensions in practical terms. There is a problem with this.

On the other hand, as disclosed by the present applicant in Japanese Patent Application Laid-Open No. 54-22057, in order to increase the size and capacity of the device, a plurality of sun rollers or inner rollers made of elastic material are installed in the axial direction. It is also possible to line them up.

However, when the elastic sun rollers and elastic inner rollers of the shape shown in the above publication are installed side by side, the pressing force in the axial direction (pressing force) corresponding to the amount of deformation of the outer diameter of these rollers is proportional to the amount of deformation of the outer diameter of these rollers. The problem is that it does not change, making it difficult to adjust.

It is also conceivable to connect and arrange a plurality of inner rollers 30 shown in FIG. 3 and sun rollers 1 shown in FIG. 1 and inner roller 3
There is a problem that the stress distribution at zero becomes asymmetrical, causing uneven contact and shortening the life.

The present invention attempts to solve the above-mentioned problems by reducing the weight per transmitted power and external dimensions, while providing good pressing force characteristics that can be adjusted, and providing sufficient durability. It is an object of the present invention to provide a planetary roller type power transmission device equipped with double row type elastic rollers that can be held in place.

Therefore, the planetary roller type power transmission device of the present invention connects a plurality of planetary rollers that are in contact with the outer periphery of the sun roller connected to the rotating shaft and the inner periphery of the inner roller fixed to the stationary member, respectively, to the rotating shaft. In the device for transmitting power between the two rotating shafts by being pivotally supported by a carrier connected to the a pair of thick-walled cylinders configured in a double-row type in which rollers are arranged in a row, each elastic roller being separated in the axial direction of the rotating shaft and having side end surfaces substantially perpendicular to the axis of the rotating shaft; a thin-walled cylindrical section formed thinner than the thick-walled cylindrical section and having either an inner or outer circumferential surface serving as a contact surface with the mating roller; and a thin disc part that individually connects both ends of the cylindrical part to the thick cylindrical part, and an elastic roller that changes the diameter of the thin cylindrical part when both ends of the thick cylindrical part are pressed. The invention is characterized in that a plurality of the elastic rollers are disposed in the axial direction so that the side end surfaces of the thick-walled cylindrical portion are brought into contact with each other.

Hereinafter, embodiments of the present invention will be explained with reference to the drawings. Fig. 8 shows the main part of a planetary roller type power transmission device equipped with double row type elastic rollers as a first embodiment of the present invention. FIG. 9 is a cross-sectional view showing the main parts of a device according to a second embodiment of the present invention, and in FIGS. 8 and 9, the same reference numerals as in the previous figures indicate the same parts.

The first embodiment shown in FIG. 8 is a device in which two inner rollers 30 are arranged in the axial direction, and these inner rollers 30 are composed of a thin cylindrical portion 30a, a thick cylindrical portion 30b, and a thin cylindrical portion 30b. The shape of the disc portion 30c and the manner in which they are connected are the same as in the case of FIG. 4.

The contact surface 30d of each inner roller 30 is in contact with a corresponding one of the pair of planetary rollers 2, 2 arranged in a row on the planetary pin 5 via the needle bearing 4.

Each planetary roller 2 abuts within a circumferential groove 1a of the sun roller 1, thereby preventing each planetary roller 2 from moving in the axial direction.

As in the first embodiment, the inner rollers 30 are arranged in a row as elastic rollers, and a pressing force T is applied to the side end surface 30e substantially perpendicular to the axis of the rotating shaft, so that each inner roller 30 A pressure contact force P is generated between the inner rollers 30 and the planetary rollers 2 that come into contact with the inner rollers 30, and the amount of power that can be transmitted can be increased in accordance with the increased number of inner rollers 30.

A second embodiment of the present invention shown in FIG. 9 shows a case where the sun roller 100 is a double row type elastic roller, 100a is a thin cylindrical part, 100b is a thick cylindrical part, 100c is a thin disc part, 100d is the contact surface,
100e is a side end face, and the shape and manner of connection of these elements are the same as in FIG. 6.

That is, the sun rollers 100 as two elastic rollers are mounted on the input shaft 80 so as to be movable in the axial direction through spline engagement and rotatable together with the input shaft 80. 80
It is tightened and fixed by a nut 19 that is screwed into the male threaded portion of the tip.

Further, although not shown, an embodiment in which the planetary rollers are formed in a double-row type similar to that shown in FIG. 9 is of course also possible.

Furthermore, in each of the above embodiments, the sun roller,
Although one of the planetary rollers and the inner roller is a double-row elastic roller, a part or all of the above rollers may be a double-row elastic roller.

As detailed above, according to the planetary roller type power transmission device equipped with double-row elastic rollers of the present invention,
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, by a carrier connected to a rotating shaft, In the device for transmitting power between the two rotating shafts, all or part of the sun roller, planetary roller, and inner roller are configured in a double-row type in which a plurality of elastic rollers are arranged in a row in the axial direction. , each elastic roller includes a pair of thick-walled cylindrical portions that are separated in the axial direction of the rotating shaft and have side end surfaces substantially perpendicular to the axis of the rotating shaft; and a pair of thick-walled cylindrical portions that are thinner than the thick-walled cylindrical portions. a thin-walled cylindrical portion with one of its inner and outer circumferential surfaces serving as an abutting surface with the mating roller; and a thin-walled cylindrical portion that is formed thinner than the thick-walled cylindrical portion and has both ends of the thin-walled cylindrical portion separated into the thick-walled cylindrical portion. and a thin disk connected to the thick cylinder, and an elastic roller that changes the diameter of the thin cylinder when both ends of the thick cylinder are pressed, and a plurality of the elastic rollers are arranged in the axial direction. Since the structure is such that the side end surfaces of the individual thick-walled cylindrical portions are placed in contact with each other, the weight per transmitted power and external dimensions are reduced, while good pressing force (pressing force) characteristics are achieved. This makes it possible to adjust the settings while maintaining sufficient durability.

That is, both side end surfaces of the thick cylindrical portion of the elastic roller are formed approximately at right angles to the axis of the rotating shaft, and the side end surfaces of adjacent rollers are brought into contact with each other, so that deformation of each roller is prevented. are performed independently, and the stress distribution does not become asymmetrical due to the high rigidity of the connection, which would occur if both rollers were connected to each other.
This has the advantage of preventing uneven contact and improving durability.

[Brief explanation of drawings]

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 the - line in Figure 1. 3 to 5 show an example of the device that is the premise of the present invention. FIG. 3 is a sectional view along the axis of the rotating shaft, and FIG. 4 is a sectional view showing the shape of the elastic roller. 5 are line diagrams showing changes in pressing force, and FIGS. 6 and 7 are sectional views corresponding to FIG. 3, showing other examples of the device on which the present invention is based, FIG. 8 is a sectional view showing the main parts of a planetary roller type power transmission device equipped with double-row elastic rollers as a first embodiment of the present invention, and FIG. 9 is a sectional view of the device as a second embodiment of the present invention. FIG. 3 is a cross-sectional view showing main parts. 1... Sun roller, 1a... Circumferential groove of sun roller, 2... Planetary roller, 3... Inner roller, 4...
Bearing, 5... Planet pin, 6... Carrier, 8...
Input shaft, 9...Pin, 10...Casing, 11
... Output shaft, 12 ... Bolt, 13, 14 ... Bearing, 15 ... Shim, 16 ... Casing cover,
17... Nut, 18... Bolt, 19... Nut, 30... Inner roller, 30a... Thin cylindrical portion,
30b...thick cylinder part, 30c...thin disc part,
30d...Abutting surface, 30e...Side end surface, 80...
Input shaft, 100... Sun roller, 100a... Thin cylindrical part, 100b... Thick cylindrical part, 100c...
...Thin disc portion, 100d...Abutment surface, 100e...
...Side end surface, 200... Planetary roller.

Claims (1)

[Scope of utility model registration request] 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, by a carrier connected to a rotating shaft, In the device for transmitting power between the two rotating shafts, all or part of the sun roller, planetary roller, and inner roller are configured in a double-row type in which a plurality of elastic rollers are arranged in a row in the axial direction. , each elastic roller includes a pair of thick-walled cylindrical portions that are separated in the axial direction of the rotating shaft and have side end surfaces substantially perpendicular to the axis of the rotating shaft; and a pair of thick-walled cylindrical portions that are thinner than the thick-walled cylindrical portions. a thin-walled cylindrical portion with one of its inner and outer circumferential surfaces serving as an abutting surface with the mating roller; and a thin-walled cylindrical portion that is formed thinner than the thick-walled cylindrical portion and has both ends of the thin-walled cylindrical portion separated into the thick-walled cylindrical portion. and a thin disk connected to the thick cylinder, and an elastic roller that changes the diameter of the thin cylinder when both ends of the thick cylinder are pressed, and a plurality of the elastic rollers are arranged in the axial direction. 1. A planetary roller type power transmission device equipped with double-row elastic rollers, characterized in that the side end surfaces of the thick-walled cylindrical portions are arranged in contact with each other.