JPS5854299B2 - Friction roller transmission device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a constant rotation speed ratio friction roller transmission.

In a friction roller transmission device, in order to facilitate the transmission of large torque, a large pressing force is required so that the friction rollers engage with each other.

When the friction rollers are engaged with each other with slight slippage just before significant slippage occurs, a large tangential force acts on the rotating surface.

However, if the axes of the friction roller are completely parallel, the same large force will act in the axial direction of the friction roller as in the tangential direction.
The friction rollers are moved axially relative to each other by the frictional forces generated by the mutually engaging rotating surfaces.

If it is not possible to keep the axes of the friction rollers perfectly parallel, an axial force that is equal to the tangential force will always act.

Of course, in this state, a large axial load is applied to the roller bearing, and a large amount of wear occurs on the rotating surface of the roller.

The main object of the invention is therefore to provide a friction roller transmission in which a plurality of friction rollers of the transmission are guided in positions perfectly parallel to each other.

To this end, the invention provides a friction roller transmission having a plurality of rotatable friction rollers with friction surfaces arranged in frictional engagement with each other, in which at least one of the friction rollers The one friction roller is guided by a lubricant provided in the transmission device, which is provided in the same direction and is close to the side surface of the other friction roller, and draws lubricant present in the transmission device into the gap between the side surface and the guide surface. A friction roller transmission featuring a guiding device that forms a pressurized lubricant pad therebetween that guides it into alignment with a surface.

Such an arrangement reduces wear on the friction surfaces and greatly extends the life of the transmission.

The invention will become more readily apparent from the following description of preferred embodiments, which are shown by way of example only in the accompanying drawings.

FIG. 1 shows the construction of the invention in a transmission of the type described in U.S. Pat. No. 3,109,922, in which a friction ring 10 and a sun roller 18
3 engaged with the sun roller 18 to transmit power between
It surrounds the two friction rollers 12°14.16.

The sun roller 18 is connected to the end of the input shaft or is formed to form part of the input shaft, and the friction ring 10 is attached to the output shaft if the transmission is used as a reduction gear.

Since the axes of the sun roller 18 and the friction ring 10 are parallel to each other and separated by a distance a, an annular passage of varying width is formed between the friction ring 10 and the sun roller 18.

Friction roller 12 is provided in the widest passage portion, and friction rollers 14 and 16 are provided in the narrowest passage portion.

Although both friction rollers 14, 16 are free to move toward the narrow passage section, the movement of these friction rollers 14, 16 away from the narrow passage section is described, for example, in U.S. Pat. It is limited by the engaging bodies 20, 22 as described in US Pat. No. 3,776,051.

Such a configuration is suitable for transmitting motion between the sun roller 18 and the friction ring 100.
0, press all friction rollers 12, 14, 16 firmly into engagement.

To guide the friction rollers 12, 14, 16, the friction ring 10 is provided with guide rails 24, as shown clearly in FIG.
26 are provided.

The guide rails 24 and 26 each form a flange, and are connected to the friction ring 10 at their radially outer ends, and are provided at their radially inner ends in close proximity to or in close contact with both sides of the friction rollers 12, 14, and 16. As shown in the figure, there are opposing annular guide surfaces 28, 30 having a trapezoidal cross-sectional shape, which guide the friction ring 10 and the friction rollers 12, 14, 16 to be aligned when the friction ring 10 is operated. do.

The guide surfaces 28, 30 are moderately inclined to form a wedge between the side walls of the friction roller and the radially inner and outer end guide surfaces, drawing in the lubricant present in the transmission.

Preferably, the friction rollers 12, 14, 16 have rims 36, 38 at their radially outer ends, with guide surfaces 28, 30 spaced inwardly from the inner diameter of the friction ring 10; Friction roller rim 36,38 and guide surface 28,3
00 (rust portions 32 and 34 are formed at a distance from a plane passing through the sun roller 18 and the axis of the friction roller 12).

The lubricant drawn into the wedge portions 32, 34 forms a pressurized lubricant pad, which seals the guide surfaces 28.30 and the rim 36.
Since the gap between the 38 and 38 increases and decreases in a wedge shape, the pressure of the oil film formed within this wedge thickness also increases and decreases over a wide range.

This, of course, means that there is no engagement between the guide surface and the side surface of the friction roller, and therefore no wear, the friction roller and the friction ring 10
creates a large moment that modifies the rotational direction of the friction roller to maintain proper alignment with the friction roller.

The gap between the guide surfaces 28, 30 and the rim 36, 38 of the friction roller should be sufficiently large to avoid significant drag forces that occur when the pressures created in the lubricant pad between the guide surfaces 28, 30 and the rims 36, 38 of the friction rollers are large. , a large correct moment occurs.

The friction roller must, of course, run freely to be guided by the guide rail, but it only needs to have such a small alignment that special bearings or special support structures for the friction roller are not necessary.

As shown in FIG. 2, the single ball bearing 40 supporting the friction roller 12 has a sufficient degree of freedom compared to the required degree of alignment.

In large devices, the friction rollers can be supported by two rows of loosely assembled ball bearings with outwardly opening contact angles or alternatively spherical roller bearings.

A small diameter friction roller does not provide enough space inside the friction roller to receive the bearing.

Therefore, it is necessary to support the friction roller shaft in a manner that allows the shaft to swing so that the friction roller can be brought to an appropriate position relative to the friction ring 10.

As discussed, the roller transmission can be part of the engine drive, can be located within the housing of the transmission, or can be provided within the housing, for example as shown in FIG. Friction ring 10 is shown supported on shaft 2 within housing 4 by bearings 6, and sun roller 18 extends through an opening 8 in housing 4.

With the described configuration, the rollers are maintained in proper alignment by fluid forces, resulting in minimal wear on the friction rollers and ring surfaces.

However, the invention is not limited to the structure as described.

It is also applicable to conventional friction wheel transmissions with associated guide rails provided radially outwardly of one of the outer surfaces of the wheels.

Also, the side surfaces of the friction rollers may be radially inclined in addition to or instead of the guide rail surfaces.

Although the guide rails are illustrated as being rotatably supported together with the friction ring, they may also be attached to the transmission housing on both sides of the friction roller.

In this case, although it is attached to the housing, it does not rotate together with the friction ring and remains stationary, and it does not need to be an annular body, but can also be formed on the housing wall portion adjacent to the friction roller.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of a preferred embodiment of the invention in which three friction rollers are provided in the space between the sun roller and the friction ring;
FIG. 2 is a sectional view of the drive device taken along line 1--2 in FIG. In the figure, 10...Friction ring, 12, 14, 16
...Friction roller, 18...Taiyo port, 24.26...Guide rail, 28.30...
...Guidance surface, 32, 34...Wedge part,
36, 38...rim, 40...bearing.

Claims (1)

[Claims] 1 First and second rotatably supported on housing 4
A sun roller 18 and a friction ring 1 fixed respectively to the shaft of
0, at least one friction roller 12 interposed between the sun roller 18 and the friction ring 10 to transmit rotation between them, and an annular guide surface 28 having a trapezoidal cross section;
30, the guide rails 24, 26 are connected to the friction ring 1.
0 or on the housing 4 so that the friction rollers 12 are aligned in the radial direction with respect to the friction ring 10, and trapezoidal guide surfaces 28, 30 are provided on both sides 36, 38 of the friction row 212. The upper base of is in close contact with or close to,
A friction roller transmission device characterized in that both slopes of the trapezoid form an oil wedge when the friction roller 12 rotates.