JP2008202707A - Frictional differential planetary-transmission - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a frictional differential planetary-transmission having a high durability, a simple structure, and reduced cost wherein an input shaft and an output shaft are coaxial with each other, and despite a reduced number of reduction-stages, a high reduction ratio can be achieved. <P>SOLUTION: The frictional differential planetary-transmission includes a sun roller which is integrated with an input shaft supported rotatably in a housing, a plurality of planet rollers circumscribed around the sun roller, a cage which is provided in the perimeter of the sun roller so as to keep a regular space between each of the planet rollers, a cylindrical outside-roller fixed in the housing, a thin-walled cylinder which is placed between the inside surface of the outside roller and the outside surface of the planet rollers, and has an outside peripheral length shorter than the inside peripheral length of the outside roller, and an output shaft which is freely rotatably supported in the housing and coupled to the thin-walled cylinder. A power is transmitted by frictional force produced by the push between the thin-walled cylinder and the outside roller. A graded part is provided on the outside peripheral surface of the planet rollers, the planet rollers and the input shaft are axially press fit into the inside peripheral-part of the thin-walled cylinder. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

The present invention relates to a small and low-cost frictional differential planetary power transmission device in which an input shaft and an output shaft are placed on the same axis, and a large reduction ratio can be obtained with a small number of reduction stages.

  A gear-type reduction gear (trademark: Harmonic Drive, hereinafter referred to as harmonic drive) is a gear-type reduction gear that can obtain a large reduction ratio by one-stage reduction by placing the input shaft and the output shaft on the same axis. )It has been known. This harmonic drive has an elliptical inner ring and a flexible outer ring, uses bearings that roll on each other via rolling elements, fixes the inner ring to the input shaft, provides teeth on the outer circumference of the outer ring, When the inner ring rotates once together with the input shaft, the long shaft end of the outer ring causes the teeth provided on the outer ring to move to the teeth of the inner gear. The outer ring is elliptical and has a shorter circumference than the inner gear, and the outer ring has fewer teeth than the inner gear. The tooth at the end of the long axis that has returned to its original position is a tooth that has advanced beyond the original tooth position of the outer ring by the number of missing teeth. Accordingly, when the inner ring rotates once, the outer ring rotates in the reverse direction by the number of missing teeth, and if this rotation is taken out to the output shaft, a reduction gear can be obtained. Since this harmonic drive uses gears, there are problems such as a reduction ratio being restricted and a large backlash due to various design restrictions based on the characteristics of the gears. In order to avoid this drawback, a friction type differential planetary power transmission device has been proposed in which a roller is used instead of a gear and the force is transmitted by a frictional force.

  There are various proposals of this friction type differential planetary power transmission device, but the one disclosed in Patent Document 1 will be described as an example. This power transmission device includes a solar member having a cylindrical outer peripheral surface arranged so that a central axis coincides with a predetermined rotation axis c, and a cylindrical outer periphery that circumscribes the outer peripheral surface of the solar member and transmits power by friction. A plurality of planetary drive members each having a surface, and a plurality of planetary drive members are supported so as to be able to rotate so that the rotation axis of rotation is parallel to the rotation axis c, and can revolve around the rotation axis c together. A rigid ring having a cylindrical inner peripheral surface that circumscribes the outer peripheral surfaces of a plurality of planetary drive members arranged so that the center axis coincides with the rotation axis c and transmits power by friction. An inner circumferential surface having a circumferential length slightly smaller than the circumferential length of the inner circumferential surface of the rigid ring, which is arranged so that the central axis coincides with the rotation axis c, and the inner circumferential surface of the flexible ring Due to partial elastic expansion deformation Those which comprise a flexible ring for power transmission by friction circumscribe the outer peripheral surface of a plurality of planetary drive member.

  As another example, a reduction gear disclosed in Patent Document 2 will be described. The speed reducer includes a drive roller rotatably supported by a plurality of drive pins fixed at equal intervals on the circumference of a flange-shaped carrier formed integrally with an input shaft, and the plurality of drive rollers A cup-shaped thin cylindrical body inscribed in the outer periphery of the thin-walled cylinder and a non-rotating cylindrical body having a U-shaped cross section inscribed in the outer periphery of the thin-walled cylindrical body. The U-shaped non-rotating cylindrical body is fixed to the casing. When the U-shaped upper part is pushed from the side by the casing cover, the bottom of the U-shape is bent and protrudes downward, and a pressing force is generated with the thin cylindrical body sandwiched between the driving roller. The speed reduction action is the same as in the previous example, and the output shaft is suspended from the cup-shaped bottom surface of the thin cylindrical body.

JP 2002-89641 A Japanese Utility Model Publication No. 60-150354

In this type of frictional differential planetary power transmission device,
(1) Selection of structure and material considering the durability of the outer member or thin cylindrical body.
(2) A method of applying pressure between the input shaft (sun roller), the planetary roller (drive roller), and the output shaft (thin cylindrical body).
(3) Since the carrier, which is a cage for the planetary roller, is directly connected to the input shaft and rotates at a high speed, the friction loss associated with the rotation increases and the power loss increases.
The concrete means about is an important technology.
The present invention is a small friction differential planetary in which the input shaft and the output shaft are coaxial, the number of reduction stages is small, the reduction ratio is extremely large, the durability is high, the structure is simple, the assembly is easy, and the cost is low. It aims at providing the concrete means regarding a power transmission device.

(1) A friction type differential planetary power transmission device as a first means includes a sun roller integral with an input shaft rotatably supported in a housing, a plurality of planet rollers circumscribing the sun roller, A retainer provided on the outer periphery of the sun roller so as to maintain a constant spacing between the planetary rollers, a cylindrical outer roller fixed in the housing, an inner surface of the outer roller, and the plurality of the plurality of planetary rollers A thin cylindrical body that is fitted between the outer surface of the planetary roller and has an outer peripheral length smaller than the inner peripheral length of the outer roller, and an output shaft that is rotatably supported in the housing and connected to the thin cylindrical body. A friction type differential planetary power transmission device that transmits a force by a frictional force caused by a pressing force between the sun roller, the plurality of planetary rollers, the thin cylindrical body, and the outer roller, the outer circumference of the planetary roller The slope is on the surface Vignetting, and the planetary roller and the input shaft is equal to or press-fitted along the axis to the inner peripheral portion of the thin cylindrical body.

  (2) The friction type differential planetary power transmission device of the second means includes a sun roller integral with an input shaft rotatably supported in a housing, a plurality of planetary rollers circumscribing the sun roller, and the plurality of planetary rollers A retainer provided on the outer periphery of the sun roller so as to maintain a constant spacing between the planetary rollers, a cylindrical outer roller fixed in the housing, an inner surface of the outer roller, and the plurality of the plurality of planetary rollers A thin cylindrical body that is fitted between the outer surface of the planetary roller and has an outer peripheral length smaller than the inner peripheral length of the outer roller, and an output shaft that is rotatably supported in the housing and connected to the thin cylindrical body. A friction type differential planetary power transmission device that transmits a force by a frictional force caused by a pressing force between the sun roller, the plurality of planetary rollers, the thin cylindrical body, and the outer roller, the outer circumference of the planetary roller The slope is on the surface Vignetting, and the planetary roller and the input shaft, characterized in that the input and Chikarako assembly press-fitted along the axis to the inner peripheral portion of the thin cylindrical body was shrunk to the outer roller.

(3) The friction type differential planetary power transmission device of the third means is the friction type differential planetary power transmission device of the first means, wherein the cage is a punch type or hollow type cage type cage. It is characterized by being.

(4) The friction type differential planetary power transmission device of the fourth means is the friction type differential planetary power transmission device of the second means, wherein the cage is provided with a pin passing through the axis of the planetary roller. It is characterized by that.

(5) The friction type differential planetary power transmission device of the fifth means is the friction type differential planetary power transmission device of any one of the first to fourth means, wherein the thin cylindrical body is connected to the plurality of planetary rollers. It is characterized by being in pressure contact with the outer roller.

(6) The friction type differential planetary power transmission device of the sixth means is the friction type differential planetary power transmission device of any one of the first to fifth means, wherein the thin cylindrical body is a high-strength aluminum having high elasticity. It is made of an alloy or stainless steel, and a high stress reducing means is formed in the central portion of the thin cylindrical body in the axial center direction.
(7) The friction type differential planetary power transmission device of the seventh means is the friction type differential planetary power transmission device of the sixth means, wherein the high stress reducing means is a plurality of elongated holes. To do.

The invention according to claim 1 is advantageous in that the assembly by press-fitting is facilitated and the cost can be reduced.
In the invention according to claims 1 to 5, since the pressing force between the rollers is obtained by press-fitting or shrink-fitting performed at the time of assembly, there is an effect that a simple structure can be achieved and the cost can be reduced. In addition, the planetary roller mechanism driven by the sun roller directly connected to the input shaft rotates at a rotational speed reduced by one step. Therefore, the rotational speed of the planetary roller and the cage is reduced accordingly, and the friction loss due to the rotation can be reduced. effective. In addition, the thin cylindrical body is in pressure contact with the plurality of planetary rollers and the outer roller, so that the power is transmitted by the frictional force between the sun roller, the planetary roller, the thin cylindrical body, and the outer roller, the sun roller, the planetary roller, The product of the planetary reduction ratio by the thin cylindrical body and the reduction ratio by the ratio of the inner diameter length of the outer roller and the outer diameter of the thin cylindrical body and the inner diameter length of the outer roller can be the total reduction ratio of input and output. .

In the invention according to claims 6 to 7, since only the thin-walled cylinder is formed of high-strength aluminum alloy or stainless steel, the output shaft and the thin-walled cylinder that rotate integrally are manufactured and joined separately. The material of the cylindrical portion can be easily changed with respect to the shaft portion, and the cost can be reduced. Further, since high stress reducing means such as a plurality of long holes, slits, and circular holes are provided in the high stress generating portion due to the deformation of the thin cylindrical body, there is an effect of improving durability.

(First embodiment)
A first embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a cross-sectional view taken along the axis of the frictional differential planetary power transmission device according to the first embodiment of the present invention, FIG. 2 is a cross-sectional view taken along the line AA in FIG. 1, and FIG. Sectional views showing the output shaft side assembly and the input shaft side assembly, and FIGS. 4 to 8 are sectional views of a thin cylindrical body having various high stress reducing holes.
In FIG. 1, 1 is an input shaft, 2 is a sun roller formed integrally with the input shaft 1, and 3 is a plurality of planetary rollers (showing the case of three) circumscribed on the sun roller 2, 4 Is a holder that holds the circumferential positions of a plurality of planetary rollers 3 at a constant distance from each other, and is rolled into a roller shape at an equal angle so that the planetary rollers can rotate freely from a donut-shaped plate. The inner diameter is a shape that can be loosely fitted to the sun roller 2. 1 and 2 show the case of a machined die. 5 is a thin cylindrical body whose outer peripheral surface is circumscribed to the planetary roller 3, 6 is an output shaft integrally coupled to the thin cylindrical body 5, 7 is an outer roller whose outer peripheral surface is circumscribed to the thin cylindrical body 5, 8 and 9 Are a housing and a housing cover, respectively. The thin-walled cylindrical body 5 is made of high-strength aluminum alloy such as Al-Cu alloy or Al-Mg-Si alloy having high elasticity or stainless steel, and one end is fitted with a planetary roller on its inner periphery, That is, a thick portion is provided on the side of the anti-planetary roller and is coupled to a flange 6 a provided on the output shaft 6.
The input shaft 1 is rotatably supported at both ends via bearings 31 and 32 provided on the housing cover 9 and the flange 6a of the output shaft 6, respectively. A washer 11 positioned through a large-diameter flange 1a formed integrally with the input shaft 1 and a C-ring 33 is provided to restrain the position of the planetary roller 3 in the axial direction. The output shaft 6 has a flange 6a at one end (the right side in FIG. 1). One end of the thin cylindrical body 5 is coupled to the flange 6a, and the other end (the left side in FIG. 1) is coaxial with the input shaft 1. The housing 8 is rotatably supported via two bearings 34 and 35. The outer roller 7 is fitted into the housing 8 and is fixed by being sandwiched from the side by the housing cover 9.

Further, in FIG. 3, the output shaft side assembly 15 in which the thin cylindrical body 5 and the output shaft 6 in the free state drawn from FIG. 1 are coupled to the left side, and the input shaft 1 and the sun roller drawn from FIG. 2, an input shaft side assembly 16 comprising a planetary roller 3 and a cage 4 is shown, and the outer roller 7 is shown in the position at the time of assembly for reference.
In the free state before assembly, the thin cylindrical body 5 is a cylindrical body having a diameter smaller than the inner peripheral surface of the outer roller 7 and an appropriately thin wall thickness, and one end side (the left side in the figure, that is, the output shaft side) faces inward. The thick flange 5a is press-fitted into a large-diameter flange 6a provided at the right end of the output shaft 6, and is fixed by a spring pin 36 or the like if necessary. For this reason, the thin cylindrical body 5 can freely use a material different from that of the output shaft 6. Further, the difference between the inner diameter of the outer roller 7 and the outer diameter of the thin cylindrical body 5 in the free state results in a difference in circumferential length, which is directly related to the speed ratio i of the frictional differential planetary power transmission device as will be described later. In order to reduce the speed ratio i (increase the reduction ratio 1 / i), it is usually made extremely small. This difference in circumferential length is also related to the durability of the thin cylindrical body 5.

  As shown in FIG. 3, the outer peripheral part of the planetary roller 3 has the gradient part 3a, the bending part 3c, and the cylindrical surface 3b. The gradient portion 3a is a gentle inclined surface that descends from the cylindrical surface 3b toward the left side in the drawing, that is, toward the output shaft side, and the bent portion 3c between the cylindrical surface 3b parallel to the axis is connected by a gentle curve. . In the input shaft side assembly 16, the dimension of the circumscribed circle formed by the plurality of planetary rollers 3 circumscribing the sun roller 2 plus twice the thickness of the thin cylindrical body 5 in the free state is The diameter of the circumscribed circle at the tip of the output shaft side of the gradient portion 3a is slightly smaller than the inner diameter of the thin cylindrical body 5 in the free state. In the state shown in FIG. 3, the input shaft side assembly 16 is moved toward the output shaft side assembly 15 while aligning the axes thereof, and a plurality of planetary rollers 3 circumscribing the sun roller 2 of the input shaft side assembly 16. Is press-fitted inside the thin cylindrical body 5 of the output shaft side assembly 15 in the free state, the portion where the thin cylindrical body 5 is pushed by the gradient portion 3a of the planetary roller 3 moves to the outer peripheral portion, and the planetary roller 3 As shown in FIGS. 1 and 2, the thin cylindrical body 5 is fitted between the inner surface of the outer roller and the outer surfaces of the plurality of planetary rollers. At this time, the cross section of the planetary roller 3 is slightly deformed into an elliptical shape, and the reaction force in the diametrical direction of the planetary roller 3 due to this deformation causes the tip of the opening side of the thin cylindrical body 5 to be deformed into a triangular bellows shape, A pressing force is applied between the roller 2, the planetary roller 3, the thin cylindrical body 5, and the outer roller 7.

When the input shaft side assembly 16 is press-fitted inside the thin cylindrical body 5 of the output shaft side assembly 15 in the free state, the right end opening surface (input shaft side) of the thin cylindrical body 5 in the figure becomes a triangular rice ball shape. The left end surface (output shaft side) is deformed into a conical surface with a circular shape, but this conical surface is a ruled surface and is relatively easy to deform. When the planetary roller 3 is further inserted, the tip portion of the weight-like surface becomes a column surface parallel to the axis, and the connection portion with the weight-like surface becomes a double curved surface, which makes it difficult to deform and causes high stress in this portion. There is a problem that the durability is deteriorated. 4 to 8 show the thin-walled cylindrical body 5 in which the friction type differential planetary power transmission device is in operation, and the upper side of each figure is strong because the thin-walled cylindrical body 5 abuts against the planetary roller 3. The state where deformation occurs, the lower side shows a state in which the thin cylindrical body 5 is not in contact with the planetary roller 3 and the deformation is weak, and each part of the cylindrical wall of the thin cylindrical body 5 is shown on the upper side during operation. The transition from the deformation state to the weak deformation state shown on the lower side is repeated.

B, C, and D shown in FIG. 4 indicate the double curved surface portion, the conical surface portion, and the column surface portion in the thin-walled cylindrical body 5, respectively. As described above, the double curved surface portion that is located at the axial center portion. Since a high stress is repeatedly generated in B, there is a problem that the material is fatigued and durability is lowered. For this reason, a reduction hole for generating high stress is provided to reduce the generation of high stress by lowering the rigidity in the vicinity of the double curved surface portion B corresponding to the bent portion 3c of the planetary roller 3.
4 to 8 show various examples of holes or slits that reduce this high stress.
FIG. 4 shows a structure in which a large number of long holes 5b are provided along the axis in the circumferential direction of the double curved surface portion B of the thin-walled cylindrical body 5. The long holes 5b have a twist angle as shown by a two-dot chain line. It is good also as the long hole 5c slanted to the axis line by (alpha).
FIG. 5 shows the elongated hole 5c in FIG. 4 having a larger twist angle α (decreasing the advance angle) and increasing the number to form a thin slit 5d.
FIG. 6 shows the slit 5d of FIG. 5 that is further increased in the twist angle α to reduce the number thereof, thereby forming a long spiral slit 5e. The slit 5e is applied when the thin cylindrical body 5 is thick, and the number of slits 5e is preferably plural so as not to reduce the transmission torque, and the figure shows the case of two. FIG. 7 shows a structure in which a large number of circular holes 5f are formed in, for example, a zigzag shape in place of the long holes and slits, and a plurality of circular holes 5f are also provided in the axial direction. FIG. 8 shows a circular hole 5g formed by reducing the diameter of the circular hole 5f and increasing the number thereof.

In the frictional differential planetary power transmission device, the planetary roller 3 is rotated once along the inner peripheral surface of the outer roller 7 while the outer peripheral surface of the thin cylindrical body 5 is pressed against the inner peripheral surface of the outer roller 7 by the planetary roller 3. Then, the planetary roller 3 returns to the original position of the outer roller 7, but the outer peripheral length of the thin cylindrical body 5 is smaller (shorter) than the inner peripheral length of the outer roller 7. On the other hand, it comes to a position that exceeds the original position by a short amount (difference length). Accordingly, the thin cylindrical body 5 relatively moves by the difference length in the direction opposite to the rotation direction of the outer roller 5. The inner diameter of the outer roller 7 is Df, the outer diameter of the free cylindrical cylinder 5 is Do, the revolution speed of the center of the planetary roller 3 is ωc, the rotational speed of the thin cylinder 5 is ωo, and the center of the planetary roller 3 is I2 = ωo / ωc = (Do−Df) / Df where i2 is the ratio of the rotational speed ωo of the thin cylindrical body 5 to the revolution rotational speed ωc of
Thus, the rotation direction is the reverse direction.
Further, the diameter and rotational speed of the sun roller 2 are Ds and ωs, the diameter of the planetary roller 3 and the revolution speed of the center of the planetary roller 3 are Dp and ωc, respectively, and the revolution speed of the center of the planetary roller 3 with respect to the sun roller 2 If the ratio is i1, approximately,
i1 = ωc / ωs = Ds / 2 (Ds + Dp) = 1/2 (Dp / Ds + 1)
Thus, the rotation direction is the same direction.
Therefore, the total speed ratio i of the thin cylindrical body 5 (output shaft 6) to the sun roller 2 (input shaft 1) of the friction type differential planetary power transmission device of this configuration is approximately,
i = i1xi2 = (Do-Df) / (2Df (Dp / Ds + 1))
Thus, the rotation direction is the reverse direction.
Although the output shaft 6 connected to the thin cylindrical body 5 is used as the output shaft, the output roller 6 can be fixed and the outer roller 7 can be used as the output shaft. The speed ratio at this time becomes slightly larger, and the rotation direction is the same direction.
(Second Embodiment)

In the first embodiment, in order to facilitate the assembly by press-fitting and the management of dimensional accuracy, the planetary roller 3 has a cylindrical shape with reduced rigidity. However, this embodiment has improved component accuracy. In order to obtain a predetermined pressing force between the sun roller 2, the planetary roller 3, the thin cylindrical body 5, and the outer roller 7 at the same time, after partly press-fitting and finally assembling by shrink fitting, The structure of the planetary roller with increased rigidity will be described.
FIG. 9 is a cross-sectional view taken along the axis of the frictional differential planetary power transmission device according to the second embodiment of the present invention, and FIG. 10 is a cross-sectional view taken along the line EE of FIG. It is a figure corresponding to FIG. 1 and FIG. 2, and the structure of the planetary roller by the side of an input shaft and a holder | retainer differs.
In these drawings, 23 is a planetary roller, 24 is a cage for the planetary roller 23, and 26 is an input shaft side assembly. In both figures, the same members as those in the first embodiment are denoted by the same reference numerals.
The outer peripheral portion of the planetary roller 23 has a gradient portion 23a and a cylindrical surface 23b, and the gradient portion 23a and the cylindrical surface 23b are connected by a gentle curve. The main body of the planetary roller 23 is a solid cylinder to increase the rigidity. However, depending on the type of the cage, a pin hole for the cage may be provided in the center as a sufficiently thick cylinder. The cage 24 has two annular disks 24a facing each other at a distance slightly larger than the width of the planetary roller 23, and a small-diameter pin 24b having one end fixed to the lead plate 24 and the other end fixed by an E-ring. And is formed. This retainer 24 (referred to as a pin-type retainer) is shown as an example of a retainer used for the planetary roller 23. As the retainer, the center hole of the planetary roller 24 is abolished and a punching that retains the outside is performed. 1 or 2 may be used. However, when the pin type holder 24 is used for the planetary roller 3, the diameter of the pin may be used. Is unsuitable because becomes large.

The friction type differential planetary power transmission device according to the second embodiment is characterized in that the pressing force between the rollers is obtained by a shrink fitting method. First, a plurality of planetary rollers are circumscribed on the outer peripheral portion of the sun roller integrated with the input shaft by a cage so as to make the input shaft side assembly 26. Further, the thin cylindrical body and the output shaft are connected to form an output shaft side assembly 15. The plurality of planetary rollers of the input shaft side assembly 26 are press-fitted into the inner peripheral portion of the thin cylindrical body 5 of the output shaft side assembly 15 and assembled as an integral rotating unit assembly. At this time, since there is no outer roller 7 outside the thin cylindrical body 5, press-fitting is relatively easy. Next, the outer roller 7 is heated and expanded, and the rotary member assembly is inserted into the outer roller 7 whose inner diameter is increased, and a press-fit shrink fit is performed so that the thin cylindrical body 5 is inserted into the inner peripheral portion of the outer roller. Do. Thereafter, when the inner diameter of the outer roller 7 is reduced by cooling, the sun roller 2, the planetary roller 3, the thin cylindrical body 5, and the outer roller 7 are pressed against each other, and a pressing force is generated therebetween.
Other operations of the friction type differential planetary power transmission device of the second embodiment are the same as those of the first embodiment.

It is sectional drawing along the axis line of the friction type differential planetary power transmission device concerning the 1st Embodiment of this invention. It is AA sectional drawing of FIG. It is sectional drawing which shows the output shaft side assembly and input shaft side assembly in a free state. 4 to 8 are cross-sectional views of a thin cylindrical body provided with various high stress reducing means, and FIG. 4 is a cross-sectional view showing the case of a large number of long holes along the axis. FIG. 5 is a cross-sectional view showing a case where the twist angle α of the long hole 5c in FIG. 4 is increased and the number thereof is increased to form a thin slit 5d. It is sectional drawing which shows the case where it is set as the spiral long slit 5e which further increased the twist angle (alpha) of the slit 5d and reduced the number. It is sectional drawing which shows the case where many circular holes 5f were opened in zigzag shape. It is sectional drawing which shows the case where it is set as the circular hole 5g which made the diameter of the circular hole 5f small and increased the number. It is sectional drawing along the axis line of the friction type differential planetary power transmission device concerning the 2nd Embodiment of this invention. It is EE sectional drawing of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Input shaft 2 Sun roller 3, 23 Planetary roller 3a, 23a Gradient part 4, 24 Cage 5 Thin cylindrical body 5a Flange 5b, 5c Long hole 5d, 5e Slit 5f, 5g Circular hole 6 Output shaft 7 Outer roller 8 Housing 15 Output shaft side assembly 16, 26 Input shaft side assembly B Double curved surface portion C Conical surface portion D Column surface portion 1 / i Reduction ratio

Claims (7)

A sun roller integral with an input shaft rotatably supported in the housing;
A plurality of planetary rollers circumscribing the sun roller;
A retainer provided on the outer periphery of the sun roller so as to keep the spacing between the plurality of planetary rollers constant;
A cylindrical outer roller fixed in the housing;
A thin cylindrical body that is fitted between the inner surface of the outer roller and the outer surfaces of the plurality of planetary rollers, and has an outer peripheral length smaller than an inner peripheral length of the outer roller;
An output shaft rotatably supported in the housing and connected to the thin cylindrical body, and a frictional force caused by a pressing force between the sun roller, the plurality of planetary rollers, the thin cylindrical body, and the outer roller. A frictional differential planetary power transmission device for transmitting force,
A slope is provided on the outer peripheral surface of the planetary roller,
2. A frictional differential planetary power transmission device according to claim 1, wherein the planetary roller and the input shaft are press-fitted along an axial line into an inner peripheral portion of the thin cylindrical body. A sun roller integral with an input shaft rotatably supported in the housing;
A plurality of planetary rollers circumscribing the sun roller;
A retainer provided on the outer periphery of the sun roller so as to keep the spacing between the plurality of planetary rollers constant;
A cylindrical outer roller fixed in the housing;
A thin cylindrical body that is fitted between the inner surface of the outer roller and the outer surfaces of the plurality of planetary rollers, and has an outer peripheral length smaller than an inner peripheral length of the outer roller;
An output shaft rotatably supported in the housing and connected to the thin cylindrical body, and a frictional force caused by a pressing force between the sun roller, the plurality of planetary rollers, the thin cylindrical body, and the outer roller. A frictional differential planetary power transmission device for transmitting force,
A slope is provided on the outer peripheral surface of the planetary roller,
An input / output assembly in which the planetary roller and the input shaft are press-fitted along the axis into the inner peripheral portion of the thin cylindrical body is press-fitted to the outer roller to generate a pressing force. Friction type differential planetary power transmission device. In the friction type differential planetary power transmission device according to claim 1,
2. The friction type differential planetary power transmission device according to claim 1, wherein the cage is a punch type or hollow type cage type cage. In the friction type differential planetary power transmission device according to claim 2,
2. The frictional differential planetary power transmission device according to claim 1, wherein the retainer is provided with a pin passing through the axis of the planetary roller. In the friction type differential planetary power transmission device according to any one of claims 1 to 4,
The frictional differential planetary power transmission device, wherein the thin cylindrical body is in pressure contact with the plurality of planetary rollers and the outer roller. In the friction type differential planetary power transmission device according to any one of claims 1 to 5,
The thin cylindrical body is formed of a high-strength high-strength aluminum alloy or stainless steel,
A frictional differential planetary power transmission device, characterized in that a high stress reducing means is formed at the axial center of the thin cylindrical body. In the friction type differential planetary power transmission device according to claim 6,
The high-stress reducing means includes a plurality of long holes, and a frictional differential planetary power transmission device.

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