JPH0251649A - Planetary traction drive - Google Patents

Abstract

PURPOSE:To improve power transmission efficiency by providing tapering which closely engages outside and inside ring rollers with each other and assembling a sun roller and planetary rollers into the inside ring roller. CONSTITUTION:An outside ring roller 6 is formed into a thick wall while forming an inside ring roller 5 into a thin wall. Tapering is provided to the inside of the outside ring roller 6 and the outside of the inside ring roller 5 to closely engage both with each other. A sun roller 2 and planetary rollers 3A-3C are assembled in the inside ring roller 5. Thereby, pressing force can be applied without giving the cause of spin to the rolling bodies of the planetary rollers, etc. Thus, since the power loss caused by the superfluous movement of spin can be totally removed, the power transmission efficiency can be im proved.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to power transmission devices, and in particular to planetary traction drives.

(Prior art) Power transmission gear devices that have been commonly used have high power transmission efficiency, but because it is not possible to reduce noise below a certain limit, noise during operation often becomes a problem. . On the other hand, the Traxigon drive, which transmits power by using frictional force acting on contact surfaces such as rollers instead of gear teeth, has almost no problem with noise during operation, but does not transmit power. Reduced efficiency may be a problem. especially,
Planetary traction drives especially require great care as this loss of efficiency can be magnified.

(Means for Solving the Problems) An object of the present invention is to minimize the reduction in power transmission efficiency of a traction drive.

In particular, it is an object of the present invention to make the power transmission efficiency of a planetary traction drive, which has a power transmission ability that can compete with some gear systems among traction drives, to be on the same level as that of a gear system.

The present invention is a planetary traction drive using a ring roller, in which the ring roller has a double structure inside and outside, the outer ring roller is thick, the inner ring roller is thin, and the inner surface of the outer ring roller is This planetary traction drive is characterized in that the outer surface of the ring roller is tapered so that they closely engage with each other, and a sun roller and a planetary roller are built into the inner ring roller.

In manufacturing the planetary traction drive of the present invention, the ring roller is transformed into a polygon having the same number of sides as the number of planetary rollers, and the planetary roller and sun roller are assembled into the ring roller. The shape of the ring roller, which has been elastically deformed into a square shape, is restored to a circular shape to apply a pressing force to the roller contact surface, thereby making it possible to transmit power without generating extra motion called spin. Further, in order to facilitate polygonal deformation of the ring roller and recovery from the deformation, the ring roller has a double structure. The wall thickness of the inner ring roller is thin so that it can be easily deformed.The outer ring roller is used not only to correct the polygonal deformation of the inner ring roller into a circular shape, but also to reduce the inner diameter of the inner ring roller. The wall thickness is increased to widen the adjustment range of the pressing force.Furthermore, the inner surface of the outer ring roller and the outer surface of the inner ring roller are tapered to closely engage with each other to prevent deformation of the inner ring roller. be easily controlled.

(Function) The ring roller has a double structure, and the thickness of the inner ring roller is thinned and deformed into a non-circular shape such as a rice ball shape (rounded triangular shape). After it is assembled into the roller, this deformed ring roller is forcibly pushed into the outer thick-walled ring roller to return it to a circular shape and apply a pressing force to the rolling element such as a planetary roller. A pressing force is applied to the roller contact surface without applying a taper to the roller.

(Example) Hereinafter, the present invention will be explained in more detail with reference to Reference Examples and Examples.

(Reference Example 1) Figure 1 explains the principle of a planetary Traxigon drive that is composed of three planetary rollers (rolling elements), one sun roller, and one sun ring (ring roller). FIG. A driving force (tangential force) T=μP is generated by the pressing force P of the three planetary rollers 3A, 3B, and 3C that rotate and revolve in contact with the sun roller 2 at the center (see FIG. 2).

μ is called the traction coefficient, and is a quantity that changes depending on the amount of slippage that occurs on the contact surface.

Conventionally, in order to apply the pressing force P, a sun roller or the like has been tapered and its axial displacement has generally been utilized.

Although this method can simply and reliably apply a pressing force, the taper provided to the sun roller causes extra motion called spin, which deteriorates power transmission efficiency. The power loss due to this spin is only a few percent in a non-differential mechanism like the case shown in FIG. 1, so it does not pose much of a problem. However, when a planetary traction drive is used as a differential type, the loss of a few percent mentioned above may be magnified several tens of times. However, reducing losses is of great significance. The driving force in traction drive is
Since most of it is converted into heat, it can raise the temperature of the traction oil and cause injury to the contact surfaces.

(Embodiment 1) An embodiment of the present invention will be described with reference to model diagrams (FIGS. 2 to 4) and a practical design diagram (FIG. 5) of a non-differential planetary traction drive.

In order to apply the necessary pressing force to the planetary rollers, etc., the inner diameter of the ring roller corresponding to ring roller 5 in Fig. 1 is made slightly smaller.Of course, if the roller arrangement as shown in Fig. 1 is not changed, , it is not possible to incorporate the sun roller and the planetary roller into a ring roller.In the present invention, this ring roller is formed into a tapered double roller as shown in FIG.
A heavy ring is used, and the wall thickness of the inner ring roller 5 is made thin so that it can easily deform into a triangular shape (when there are three planetary rollers) or a square shape (when there are four planetary rollers).

The outer side of the thin ring roller 5 is tapered, and the inner side of the thick outer ring roller 6 is also tapered.

The tapers of these two rings are machined so that they fit together when no load is applied.

In FIG. 5, only the thin ring roller 5 is taken out and deformed into a triangular shape so that three planetary rollers and one sun roller can freely move in and out from the axial direction of the ring roller 5. Figure 3 shows the planetary roller 3A inside the deformed ring roller.

3B and 3C and the sun roller 2 are shown. One example of a method for realizing this deformation of the ring roller is a method of pressing the outside of the ring roller 5 at three locations using a three-jaw chuck of a lathe. After inserting the sun roller 2 and the planetary rollers 3^, 3B, and 3C into the ring roller 5 using this method, the outer periphery of the ring roller 5 was measured with a roundness measuring device, and the results are shown in FIG. It is clearly seen that the ring roller 5 is pushed by the three planetary rollers and is deformed into a triangular shape.

This deformed ring roller 5 is forcibly pushed into the thick outer ring roller 6 using screws and tapers to eliminate the deformation of the triangular outer periphery.
If necessary, it is possible to increase the pushing force, reduce the inner diameter of the ring roller 5, and increase the pushing force of the planetary roller or the like. In order to perform this pushing, screws 8^ and 8B are used to pull the ring roller catch 7 and the ring roller 6.
will be established.

Although only two tension screws, 8A and 8B, are shown in Figure 4, it is usually better to use three or more.

The planetary rollers 3A, 3B, and 3C are supported by thin shafts 4^, 4B, and 4C fixed to the flange 10 of the output shaft 9, and revolve while rotating. In order to prevent abnormal deformation of the thin ring roller, the seats 7 and 11 are provided with steps to lightly support the inside of the ring roller.

In the example of the planetary traction drive shown in FIG. 4, the diameter of the sun roller is DI = 40.70 mm - the diameter of the three planetary rollers is Dz = 29.30 mm.

The inner diameter of the ring roller is D3 = 99.17 mm.

Therefore, D,+20z =40.70+2 x29.
30 =99.30mm> D:l =99.17m+
++, so add approximately 0.13mm to the inner diameter of the ring roller.
This means that the closing margin is given. The effective width of these rollers is 40 mm. The reduction ratio is 3.4. When the rotation speed of the input shaft is 180 rpm, more than 1 in 10 power can be transmitted. The measured value of power transmission efficiency was approximately 95% near the design load conditions, which was almost the same value as the power transmission efficiency of the same type of gear reducer.

To insert the planetary roller and sun roller into the ring roller, use a three-jaw chuck for a lathe to push the outer circumference of the ring roller at three places, and insert the three planetary rollers onto the thin shaft of the flange of the output shaft. I left it installed.

(Effects of the Invention) Thus, according to the present invention, in a planetary traction drive, pressing force can be applied to rolling elements such as planetary rollers without causing spin. Therefore, the power loss caused by the extra motion of spin can be reduced to zero, so it is possible to realize a planetary traction drive with high power transmission efficiency.

That is, in a planetary traction drive with low operating noise, it is possible to obtain a power transmission efficiency as high as that of a gear device.

The device of the present invention is extremely useful for power transmission devices and power transmission transmissions, particularly those that require a power transmission efficiency as high as that of a gear device and a significantly lower noise during operation than a gear device.

Although the apparatus of the present invention has been described with reference to specific examples and numerical values, it is understood that the invention is not limited thereto and that various changes and modifications may be made without departing from the broad spirit and scope of the invention. It is.

[Brief explanation of the drawing]

Fig. 1 is a partially cutaway perspective view of a conventional planetary traction drive, and Fig. 2 is an explanatory diagram showing the pressing force P and driving force TljT2 acting on the contact surfaces of the sun roller, ring roller, and planetary roller. , Fig. 3 is a model diagram showing the state in which the sun roller and the planetary roller are inserted into the ring roller, Fig. 4 is an actual measurement diagram showing the deformation of the ring roller, and Fig. 5 is a diagrammatic cross section of an example of the device of the present invention. It is a diagram. 1... Drive shaft 2... Sun roller 3A,
3B, 3C... Planetary rollers 4A, 4B... Thin shaft 6... Thick ring rollers 8A, 8B... Tension screw lO... Flange 11 of output shaft 9... Ring roller catch 5... Thin ring roller 7... Ring roller catch 9... Output shaft

Claims (1)

[Claims] 1. In a planetary traction drive using a ring roller, the ring roller has a double structure inside and outside, the outer ring roller is thick, the inner ring roller is thin, and the inner surface of the outer ring roller and the inner ring are A planetary traction drive characterized in that the outer surfaces of the rollers are tapered so that they closely engage with each other, and a sun roller and a planetary roller are incorporated within an inner ring roller.