JPS60101353A - Planetary roller power transmission apparatus - Google Patents

Abstract

PURPOSE:To improve transmission efficiency by providing a fixed wheel formed of a material having high modulus of longitudinal elasticity such as ceramics in an apparatus in which a plurality of planetary rollers are disposed between the outer periphery of a sun wheel and the inner periphery of a fixed wheel to heighten maximum contact pressure. CONSTITUTION:Between the outer periphery of a sun wheel 3 mounted on the first rotary shaft 2 and the inner periphery of a fixed wheel 5 fitted to a housing 4, disposed are a plurality of planetary rollers 8 respectively contacting both peripheral surfaces. The respective planetry rollers 8 are rotatably supported on a planetary shaft 6 fixed to the second rotary shaft 1 through a floating bush 9. The fixed wheel 5 is formed of a material having high modulus of longitudinal elasticity such as ceramic material. Thus, the maximum contact pressure between the fixed wheel 5 and the respective planetary rollers 8 to improve transmission efficiency for turning effect. Furthermore, this arrangement can eliminate the need of pressing the planetary rollers 8 and the fixed wheel 5 and the sun wheel 3 to each other to lengthen the life of the whole apparatus.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field of the Invention The present invention provides a method for transmitting power by the frictional force of planetary rollers. ! Regarding the star roller type power transmission device.

TECHNICAL BACKGROUND OF THE INVENTION As a conventional iMf star roller type dynamic power transmission device of this type, one used as a speed reducer as shown in FIG. 1 of Japanese Patent Publication No. 58/21137, for example, is known. This known structure has a solar wheel made of steel and directly connected to an input shaft that is rotatably driven.

A fixed ring formed of a steel material that is fitted and fixed to the inner circumference of the housing, a plurality of planetary rollers that come into contact with the outer circumference of the sun ring and the inner circumference of the fixed ring, and a It consists of a plurality of planetary shafts provided, and each planetary roller is rotatably supported by the planetary shaft at equal intervals around the entire circumference and via bushes, and the sun wheel, the plurality of planetary rollers, and the fixed ring are , the planetary rollers are pressed against each other by radial contact pressure, and due to the frictional force generated by this pressure, the rotational driving force from the input shaft is decelerated and transmitted to the output shaft.

Problems with the Background Art Generally, in this type of power transmission device, the transmission efficiency of the rotational force transmitted from the input shaft to the output shaft is determined by the magnitude of the maximum contact pressure between the planetary roller, the fixed wheel, and the sun wheel. , especially the magnitude of the maximum contact pressure between the planetary roller and the fixed ring (this point will be explained in detail later in the detailed description of the invention); The larger the maximum contact pressure is, the more the efficiency of transmitting rotational force in the device can be improved. However, in order to increase the maximum contact pressure between the planetary rollers and the fixed ring, if the sun ring, planetary rollers, and fixed ring are strongly pressed against each other in the radial direction, the sun ring and the planetary rollers will come into contact with their convex surfaces. Therefore, the maximum contact pressure between the members becomes too excessive, and there is a risk that the device itself may be damaged. Therefore, in practice, by crowning the circumferential surface of the fixed ring, etc., all of the above-mentioned disadvantages are prevented, and the maximum contact pressure between the fixed ring and the planetary roller is increased.
Efforts are being made to improve the transmission efficiency of rotational force in the device.

However, when this device is used at high speed rotation, skew occurs between the planetary rollers, the sun ring, and the fixed ring, making it impossible to attach a large rouning to the inner peripheral surface of the fixed ring. , the maximum contact pressure between the fixed ring and the planetary roller decreases, and the transmission efficiency of rotational force deteriorates.

OBJECTS OF THE INVENTION An object of the present invention is to improve the maximum contact pressure between a fixed ring and a planetary roller in a planetary roller type power transmission device, and to improve the transmission efficiency of rotational force.

Summary of the Invention In this invention d, in the planetary roller type power transmission device, the fixed ring is formed of a material having a high longitudinal elastic modulus, such as a ceramic material.

Embodiment of the Invention FIGS. 1 and 2 show an embodiment in which the present invention is used as a speed increaser.

(1) is the input shaft, (2) is the output shaft, (3) is the output shaft (2
) at one end of the sun ring (
Of course, the solar ring (3) may be formed integrally with one end of the protruding shaft (2). ), (5) are fixed rings fitted and fixed on the inner circumferential surface of the housing (4), and (6) are fixed rings mounted on the end surface (1a) of the input shaft (11) at equal intervals in the circumferential direction (three in this case). This is a planetary shaft screwed in the axial direction.・This allows the planetary shaft (6)
are fixed to the input shaft (1) at equal intervals (three in this case) in the circumferential direction. (8) is a planetary roller, and each planetary shaft (6
) is rotatably supported via a floating bush (9),
Its outer periphery is in contact with the cylindrical bottom surface of a circumferential groove (3a) for rolling the planetary roller, which is formed on the inner periphery of the fixed ring (5) and the outer periphery of the sun ring (3). The floating bush (9) is interposed between the stepped portion (6a) of the planetary shaft (6) and the planetary roller (8), and is arranged between the side surface of the stepped portion (6a) and the planetary shaft (6).
It is positioned in the axial direction by a snap ring (10) fixed to the end. The fixed ring (5) is made of a ceramic material such as 813NζSi or C.

This ceramic material has a longitudinal elastic modulus E of 3X] 06 #
f/C#I', the longitudinal elastic modulus E of the bearing steel (SUJ-2) that is the material of the fixed ring of the conventional device is 2JX]Q
6 #f/(about 1.4 times higher than W. Of course, the fixed ring (5) may be formed of a material having a high longitudinal elastic modulus other than ceramic material.

In the planetary roller power transmission device, which is a speed increaser with the above configuration, the sun wheel (3), the planetary rollers (8), and the fixed wheel (5) exert radial contact pressure on their mutual contact surfaces. As a result, when the input shaft ( ]) rotates, for example, in the direction of the X arrow in Figure 2, the rotational force is increased and transmitted to the output shaft (2), causing it to rotate in the direction of the Y arrow. do. At this time, the maximum contact pressure pAmax (described later) between the fixed ring (5) and the planetary roller (8) increases.
1, the transmission efficiency of the rotational force from the input shaft (moon) to the output shaft (2) can be completely improved.

Next, in this invention, the reason why the fixed ring (5) is made of ceramics having a high longitudinal elastic modulus will be described. In general, in this kind of planetary roller type power transmission device, the planetary roller (8) and the fixed ring (5) are The maximum contact pressure PAmax that occurs in contact is: pAmax = 0.59p knee j) / (i, +
i, )[”'■ By the formula, - ten thousand, planetary roller (8)
The maximum contact pressure P BmaX caused by the contact between the solar ring (3) and the solar ring (3) can be determined by the following formula.

In each of the above equations, P: Contact pressure applied to the planetary roller r1: Outer radius of the planetary roller r2: Inner radius of the fixed ring r3: Radius of the solar ring El: Coefficient of longitudinal elasticity of the planetary roller Audience: Coefficient of longitudinal elasticity of the fixed ring E3 : Longitudinal elastic modulus of the solar ring I: Indicates the effective length of the planetary roller.

As is clear from equation 0 above, the maximum contact pressure is PA
Since max < PBmax, both members (5) (
In order to reduce the slip v between 81 and improve the transmission efficiency of rotational force in the device, the planetary roller (8) and fixed ring (5
) is necessary to make the maximum contact pressure pAmax k as high as possible. However, the planetary roller (8)
and the fixed ring (5) are strongly pressed against each other to achieve the maximum contact pressure PAmax 1. (If the height is increased, the maximum contact pressure PBmax between the members (s+ (3) will become too high because the planetary rollers (8) and the solar ring (3) are in convex surface-to-convex contact state, and the device itself will be damaged. There is a fear.

Therefore, in this invention, by using a fixed ring (51k) made of a ceramic material having a higher modulus of longitudinal elasticity than bearing steel, the fixed ring (5) and the planetary roller (8) are not pressed strongly against each other, and the sun ring ( 3) and planetary roller (8)
The maximum contact pressure PAmaX between the fixed ring (5) and the planetary roller (8) increases as the fixed ring (5) and the planetary roller (8) are pressed more strongly against each other.

Effects of the invention Does this invention have the above structure? Therefore, it has the following effects.

■ If the contact force between the planetary roller and the fixed ring is the same, the longitudinal elastic modulus E of the ceramic material is about 1.4 times larger than that of bearing steel, so the difference between the planetary roller and the fixed ring is The maximum contact pressure is about 10%.

Therefore, the transmission efficiency of rotational force in the device is improved.

- When trying to obtain the same transmission efficiency as the conventional device, there is no need to forcefully press the planetary roller, fixed wheel, and sun wheel against each other, so the life of the entire device is extended.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view of a main part of an embodiment of the present invention, and FIG. 2 is a sectional view taken along the line ■--■ in FIG. (1)-Second rotating shaft <2)--First rotating shaft (31
-...Solar ring (4)...Housing (5)--
Fixed ring (6) ... Planet 1liI11 (8) ... Planet roller (9) - Floating push Figure 1 Figure 2 (Voluntary) Procedural amendment 1, Indication of the case 1982 Patent Application No. 210585 2. Name of the invention Planetary roller type power transmission device 3. Relationship with the case of the person making the amendment Voluntary action by the patent applicant 5. Subject of the amendment (1) “Claims” column of the specification (2) No. 1 of the drawings Contents of amendments to Figures 1 and 2 66 Claims: ``Between the outer periphery of the sun ring provided on the first rotating shaft and the inner periphery of the fixed ring fitted and fixed to the housing, A planetary roller type in which a plurality of planetary rollers are placed in contact with each other, and each planetary roller is rotated by a planetary roller fixed to a second rotating shaft, thereby transmitting power between the two rotating shafts. A planetary roller type power transmission device, wherein the fixed ring is made of a material having a high longitudinal elastic modulus such as a ceramic material."

Claims (1)

[Claims] A plurality of planetary rollers are disposed between the outer circumference of the sun ring provided on the first rotating shaft and the inner circumference of the fixed ring fitted and fixed to the housing, and each of the planetary rollers abuts on the inner circumferential surface. In a planetary roller type power transmission device in which the rollers are respectively pivotally supported by planetary shafts fixed to the second rotational shaft via floating bushes, power is transmitted between the two rotational shafts. A planetary roller type power transmission device characterized in that the ring is made of a material having a high longitudinal elastic modulus such as a ceramic material.