JP2003278867A - Planetary roller type power-transmission device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent oil-leakage from an oil seal. <P>SOLUTION: A planetary type power-transmission device T/D comprises in a casing 31 a sun roller 23, a planetary roller 24, a ring roller 25, and a carrier 26. Oil is filled in the housing 31. On the outside periphery of the carrier 26, a taper wall 52 is formed, which constitutes a path in an axially further away position when viewed from the roller side. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a planetary roller type transmission device (traction drive) which transmits power by the traction rotational force (shear stress of oil) of a sun roller, a planetary roller and a ring roller.

[0002]

2. Description of the Related Art As an example of this type of planetary roller type transmission device, Japanese Patent Application Laid-Open No. 8-210455 discloses a planetary roller type speed reducer. FIG. 4 shows the speed reducer described in the publication.

The speed reducer 1 includes a sun roller 3 provided at the tip of a rotary shaft 2 of a motor 15, a plurality of planet rollers 4 circumscribing the sun roller 3, and a ring roller 5 inscribed in the planet roller 4. A carrier 6 arranged on one axial side of the rollers 3, 4, 5 and synchronized with the revolution of each planetary roller 4, and an output shaft (carrier shaft) 7 connected to one side of the carrier 6 are provided. There is. Each planetary roller 4 is rotatably attached to the outer periphery of a carrier pin 8 which is cantilevered by a carrier 6 via a needle bearing 9.

The sun roller 3, the planetary roller 4, the ring roller 5, and the carrier 6 are housed inside casings 10 and 11, and the ring roller 5 is fixed to the casing 11. The output shaft 7 is rotatably supported by a rolling bearing 12 fitted in a casing 10, and its shaft end is led out through a shaft hole 13 formed in the casing 10.

In this type of speed reducer 1, the casings 10 and 11 are filled with oil (traction oil) in order to ensure cooling and power transmission performance.
Although not shown in FIG. 4, an oil seal is usually provided in a portion 18 between the output shaft 7 and the output shaft 7.

[0006]

By the way, if the input rotation speed of the speed reducer 1 is not so high, there is no particular problem.
It was found that a new problem may occur when the input rotation speed of is set high.

That is, the inside of the casings 10 and 11 is filled with oil as described above, but when used at high speed rotation, especially due to the fast movement of the planetary rollers 4,
Since the internal oil is vigorously agitated, the dynamic pressure of the surrounding oil increases, which affects the oil seal around the output shaft 7 and may cause oil leakage.

In order to solve this, it is conceivable that the oil seal has two stages or the seal pressure is increased.
However, if so, not only the power loss due to the seal increases and the efficiency decreases, but also the axial length increases,
In addition, an increase in the number of parts and an increase in the number of assembly steps are inevitable.

In view of the above circumstances, the present invention is a planetary roller type transmission device capable of controlling the flow of oil during high speed rotation and eliminating the risk of oil leakage without installing an extra oil seal. The purpose is to provide.

[0010]

SUMMARY OF THE INVENTION According to the present invention, a sun roller, a plurality of planet rollers circumscribing the sun roller, a ring roller inscribed in the planet roller, and one axial direction of these rollers are provided inside a casing. And a carrier that is arranged on the side and rotatably supports each planetary roller, and
In the planetary roller transmission in which the casing is filled with oil, a taper wall surface having a smaller diameter is formed on the outer periphery of the carrier at a position farther in the axial direction when viewed from the roller side. Is the solution.

In the present invention, a so-called "taper wall surface" is formed on the outer periphery of the carrier, which has a smaller diameter at a position farther in the axial direction when viewed from the roller side.

This not only reduces the possibility that the dynamic pressure of the oil will increase in a narrow space due to the rotation of the planetary roller and deteriorates the sealing performance as in the conventional case, but the oil will smoothly flow to the planetary roller side. To be able to return to
The original function of oil can be exerted more.

In the present invention, the portion of the casing facing the tapered wall surface of the outer periphery of the carrier is shaped to follow the tapered wall surface of the carrier, leaving a predetermined gap. When formed, the direction of the oil that is about to be pushed outward by the centrifugal force can be returned to the roller side along the gap formed between the oil and the casing, and the load on the oil seal can be further reduced.

According to the present invention, if the outer periphery of the carrier has a taper wall surface even if it is slightly, the corresponding return effect can be obtained. However, the portion having the taper wall surface is the planet of the carrier. It is advantageous to form “large” over a range of 1/3 or more of the maximum length in each of the axial direction and the radial direction in the outer peripheral side portion with respect to the position where the pin supporting the roller exists. The effect obtained is more remarkable, which is preferable.

Further, when a predetermined gap is formed between the facing portions of the casing, the opening on the large diameter side of the predetermined gap is located near the contact surface between the planet roller and the ring roller. By facing the oil, the oil can be efficiently returned to the "portion requiring the oil".

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a cross-sectional view showing a main part structure of a motor with a traction drive shown as an embodiment.

This traction drive motor T /
Each of D and M is a motor M integrally assembled with a planetary roller type transmission device T / D (hereinafter simply referred to as “T / D”).

The T / D casing 31 comprises a front casing 31A arranged in the front portion in the axial direction, a cylindrical central casing 31B arranged in the center, and a joint casing 31C on the motor M side. The joint casing 31C also serves as a front casing (motor flange) of the motor M. The motor shaft 45 is supported at its front end side by a bearing 34 fitted into the through hole 33 of the joint casing 31C, and has its front end inserted in the center of the T / D casing 31.

T / D is a sun roller 23 arranged in the center of the casing 31, a plurality of (for example, three or four) planet rollers 24 circumscribing the sun roller 23, and a ring in which the planet roller 24 is inscribed. Roller 25 and these rollers 2
3, 24, and 25 are provided on one axial side (opposite to the mounting side of the motor M) and are provided with a carrier 26 that synchronizes with the revolution of each planetary roller 24. The sun roller 23 has a front bearing 34. It is coupled via a coupling 21 to the more protruding end of the motor shaft 45.

The carrier 26 is integrally formed like a flange on the base end of an output shaft (carrier shaft) 22 arranged coaxially with the sun roller 23. The output shaft 22, which is integrated with the carrier 26, has a tip that penetrates through a shaft hole 35 formed at the center of the front casing 31A and projects to the outside, and a rolling bearing 37 fitted to the inner periphery of the shaft hole 35. (And T /
It is rotatably supported by the bearing function of D itself).

Here, the ring roller 25 is a fixed element,
The sun roller 23 is an input element, the planetary roller 24 and the carrier 26 are output elements, and the ring roller 25 is integrally formed on the inner circumference of the cylindrical central casing 31B. Then, the joint casing 31C that also serves as the front casing (motor flange) of the motor M, the central casing 31B integrally including the ring roller 25, and the front casing 31C through which the output shaft 22 penetrates are fitted to each other. Then, by connecting with the through bolt 32, the T / D
And a motor M are integrated to form a planetary roller type transmission-equipped motor T / DM.

Each planetary roller 24 is rotatably attached to the outer periphery of a carrier pin 27 which is cantilevered by a carrier 26, and between the inner periphery of each planetary roller 24 and the outer periphery of the carrier pin 27. A needle bearing 28 that facilitates rotation of the planetary roller 24 is interposed. Spacers 38 and 39 are provided on both sides of the planetary roller 24 to position the planetary roller 24 and prevent the needle bearing 28 from falling off.

An oil seal (sealing means) 57 is provided outside the rolling bearing 37 that supports the output shaft 22, and an oil seal 58 is also provided inside the motor of the front bearing 34 of the motor shaft 45. As a result, the oil filled in the T / D does not leak to the motor M side or the outside.

Further, the inner wall of the front casing 31A and the outer periphery of the carrier 26 are tapered wall surfaces 5 that closely face each other.
1, 52 are provided.

That is, as shown enlarged in FIG. 2, a taper wall surface 52 having a smaller diameter is formed on the outer periphery of the carrier 26 at a position farther in the axial direction when viewed from the roller side, while the front casing 31A is provided. In a portion of the outer periphery of the carrier 26 facing the tapered wall surface 52, an opposed tapered wall surface 51 having a shape along the tapered wall surface 52 of the carrier 26 with a predetermined minute gap left.
Are formed.

The size of the gap between the tapered wall surfaces 51 and 52 and the length of the tapered wall surfaces 51 and 52 in the generatrix direction (corresponding to the path length when the dynamic pressure flows) are from the roller side space 61 to the oil seal side space 62. These values affect the performance of suppressing the inflow of dynamic pressure into the cylinder. Therefore, it is desirable to set these values to optimum values in light of manufacturing conditions and other dimensional conditions (strength, etc.).

In this embodiment, the tapered wall surface 52 (and the tapered wall surface 51 facing the same) on the outer periphery of the carrier 26 extends L on the axial side and R on the radial side. This is a size that extends over a wide range of 1/2 or more of the maximum lengths L1 and R1 in the axial direction and the radial direction, respectively, in the outer peripheral side of the position P1 where the carrier pin 27 supporting the planetary rollers 24 exists. That's it. Specifically, in the example shown in the figure, the L / L1 ratio on the axial side is 1 /
The R / R1 ratio on the radial direction side is 2 or more and 80% or more.

When the present invention is simply applied, it is preferable that the axial wall and the radial wall have tapered wall surfaces over a range of nearly 100%. However, in consideration of the strength of the outer peripheral side of the carrier 26 and the like, even if the formation range of the tapered wall surface on either side or both sides is suppressed to about 1/2, the advantages of the present invention can be sufficiently enjoyed in practical use.

However, in the case where both are formed in a range of less than 1/3, the advantages of the present invention are not always sufficiently obtained, which is not preferable.

In order to obtain a sufficient cutting-off effect, it is preferable to keep the gap to 0.8 mm or less.

The opening 53 on the large diameter side of the gap secured between the tapered wall surfaces 51 and 52 is arranged toward the contact surface between the planet roller 24 and the ring roller 25, as shown in FIG. .

Next, the operation will be described.

When the sun roller 23 is rotated by the motor M, the planet roller 24 inscribed in the ring roller 25 revolves around its own axis, and the planet roller 24 revolves in the route of carrier pin 27 → carrier 26 → output shaft 22. It is taken out as a deceleration output.

In the above operation, when the input rotation is high speed, the planetary roller 24 rotates / revolves at a high speed, so that the oil therein is vigorously agitated and the dynamic pressure of the oil in the casing 31 is increased. Occurs.

However, in the T / D of this embodiment, since the taper wall surfaces 51, 52 are provided between the front casing 31A and the carrier 26 so as to closely face each other with a minute gap therebetween, the taper wall surface 51. By the partitioning action of the rollers 52, 52, it is possible to reduce the inflow of dynamic pressure from the space 61 on the roller side to the space 62 on the oil seal side. Moreover, the rotation of the taper wall surface 52 on the carrier 26 side causes the taper wall surface 5 to move.
In the oil between 1 and 52, a force (component of centrifugal force) that tends to flow into the roller-side space 61 is generated, so that it is possible to more reliably prevent the dynamic pressure from flowing into the oil-seal side space 62. Therefore, it is possible to prevent the dynamic pressure from flowing into the oil seal 57 around the output shaft 22 and prevent oil leakage from the oil seal 57.

Further, the opening portions on the large diameter side of the taper wall surfaces 51 and 52 of the close-opposing walls are connected to the planet roller 24 and the ring roller 25.
The oil to be returned from the taper wall surfaces 51 and 52 is positively supplied to this portion because it is arranged toward the contact surface of No. 1, so that the oil can be used more effectively.

In the present invention, the specific shape of the tapered wall surface does not necessarily have to be linear. For example, as in the example of FIG. 3, it is convex outward in the radial direction (it may be a concave shape close to a loose S shape).
The curved tapered wall surfaces 151 and 152 may be formed.

Further, the tapered wall surface on the casing side does not necessarily have to be formed. Even if it is formed on the carrier side, a corresponding dynamic pressure reducing effect can be obtained.

[0040]

As described above, according to the present invention,
By providing the tapered wall surface on the outer periphery of the carrier, it is possible to reduce the load of oil dynamic pressure on the sealing means during high-speed rotation as much as possible. Therefore, with a slight modification to the carrier, it is possible to eliminate the risk of oil leakage during high-speed rotation while keeping the power loss to a minimum without installing an extra oil seal.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of an essential part of a motor with a traction drive (planetary roller transmission) shown as an embodiment of the present invention.

FIG. 2 is an enlarged view of part II in FIG.

FIG. 3 is a diagram showing a modification of the portion of FIG.

FIG. 4 is a sectional view showing an example of a conventional traction drive.

[Explanation of symbols]

22 ... Output shaft (carrier shaft) 23 ... The sun roller 24 ... Planetary roller 25 ... Ring roller 26 ... Carrier 31 ... Casing 31A ... Front casing 35 ... Shaft hole 51, 52 ... Tapered wall surface 57 ... Oil seal T / D ... Planetary roller transmission

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Seiji Minegishi             6-1, Asahi-cho, Obu-shi, Aichi Sumitomo             Machine Industry Co., Ltd.Nagoya Works F term (reference) 3J051 AA01 BA03 BB06 BC01 BD02                       BE03 EC02 EC10

Claims (4)

[Claims] 1. A sun roller, a plurality of planetary rollers circumscribing the sun roller, a ring roller inscribed in the planetary roller, and a planetary roller disposed on one axial side of the rollers inside the casing. In a planetary roller transmission in which a carrier that rotatably supports is arranged, and the casing is filled with oil, the outer periphery of the carrier is located farther in the axial direction when viewed from the roller side. A planetary roller type transmission characterized in that a tapered wall surface having a small diameter is formed. 2. The portion of the casing facing the tapered wall surface on the outer periphery of the carrier has a shape along the tapered wall surface of the carrier with a predetermined gap left therebetween. A planetary roller transmission characterized in that it is formed as described above. 3. The taper wall surface portion of the carrier according to claim 1 or 2, wherein a portion of the carrier on the outer peripheral side of a position where a pin supporting the planetary roller exists. A planetary roller transmission characterized by having a range of 1/3 or more of the maximum lengths in the axial direction and the radial direction. 4. The planetary roller type transmission device according to claim 2, wherein an opening on the large diameter side of the predetermined gap is exposed near a contact surface between the planetary roller and the ring roller. .