JPS62215160A - Traction roller transmission - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a fixed ratio traction roller transmission having traction rollers having lubricated hard metal contact surface areas that are tightly engaged with each other for the transmission of motion.

Such traction roller transmissions generally utilize large contact forces to prevent roller slippage. Various traction or friction roller transmissions are described in Harold A. Rospert, Handbook of Mechanical Design and Systems, pp. 14-8 and 14-9, McGraw-Hill, New York, 1964.
It is described in. In the relatively simple arrangement of Figures 14.6 and 14.7, where the outer ring is slightly undersized to compress the roller arrangement, the surface pressure on the traction surface is always the same, i.e. , it is always at maximum regardless of the torque transmitted through the transmission.

Also known are various transmission arrangements in which the contact pressure of the traction surfaces is dependent on the magnitude of the torque transmitted through the transmission, such as, for example, in the one shown on pages 14-8 of said handbook. It is being

In the arrangement according to US Pat. No. 771.541, different compression forces are achieved by an outer ring structure arranged such that the ring is compressed at a rate that depends on the torque transmitted through the transmission.

However, this arrangement either requires a sliding surface area that is difficult to manufacture and unreliable to use, or it amplifies the reaction forces of the transmission to compress the outer ring enough to engage the outer ring with the traction roller. requires a complex lever arrangement to give

U.S. Pat. No. 3,610,060 teaches that barrel-shaped planetary rollers and sun rollers are oriented toward each other when torque is transmitted through a drive to provide a positive engagement with a traction ring surrounding the planetary rollers. 2 shows a friction drive in which the sun roller consists of two slightly conical sections adapted to be forced together; However, the difference in curvature between the small sun roller and the planetary roller is so large that a large cone angle will result in substantial spin, leading to wear and friction losses. On the one hand, this transmission requires a relatively large cone angle of the conical sun roller surface to avoid locking, and on the other hand, it requires a relatively large cone angle of the conical sun roller surface to avoid locking, and on the other hand, it A relatively long line of contact between the sun roller section and the planetary roller is required in order to avoid excessively large surface pressures that are highly localized. As a result, such transmissions can only be used to transmit small amounts of power.

In a traction roller transmission having a plurality of planetary rollers disposed in an annular space formed between a sun roller and a traction ring surrounding the sun roller, the traction ring, the planetary rollers, and the sun roller For transmission of motion, the planetary traction roller has a plurality of annular protrusions and recesses with sloped, lubricated hard metal sides that engage the sun roller and traction ring. Means are provided for engaging the planetary rollers with the sun roller and the traction roller, preferably with a force dependent on the torque transmitted via the transmission.

Fixed ratio traction drives with hard metal contact surfaces exposed to the traction fluid typically cannot operate efficiently with high specific shear in the contact area due to the high contact pressures involved.

Although cylindrical rollers can transmit a significant amount of power per pound of weight, greater weight savings are desired, such as in aircraft turbine speed reducers and space applications. However, there are applications where cost is not a major concern. The deflection of the hard steel in the contact area is very small and the required manufacturing precision and therefore the manufacturing costs are very high. In fact, computer analysis of such V-drives shows that even for fairly large rollers, the contact lengths are as low as o, i inch (0,254 cm) and 0.05 for a small sun roller in a planetary configuration.
(0,127 cm),
That is, the length of the contact area must not be greater than 0.03 inches (0,0762 crn) for every inch (2,54 crn) of radial length of one sun roller, i.e., the radial contact length. When the diameter of the stitching roller is d] ri0. This indicates that it must be O15d. However, in practice the required precision can be achieved by modern lash grinding.

A traction roller transmission as shown in FIGS. 1 and 2 basically consists of a sun roller 1 disposed centrally within a traction ring assembly 3 and between the sun roller 1 and the traction ring assembly 3. traction rollers 2 arranged in an annular space.

As shown in FIG. 1, the sun roller 1 is formed at the end of the input shaft 12 with spaced circumferential grooves 13 with hard metal side surfaces 14 having a predetermined angle with respect to a plane perpendicular to the axis of the input shaft 12. has been done. The input shaft 12 has a trunnion 15 at its inner end, on which the input shaft 12 is supported by a bearing 16.

The traction ring assembly 3 consists of a housing ring 31 carrying two traction rings 32 having side surfaces 33 arranged at the same predetermined angle as the side surfaces 14 of the sun roller 1 with respect to said plane perpendicular to the axis of the input shaft 12. Become. Housing ring 31 is mounted on housing side walls 34 and 35. The input shaft 12 extends through the sidewall 34 and is preferably supported therein by an input shaft bearing 36.

An output shaft 17 is rotatably supported within the housing side wall 35 by a bearing 37, and a trunnion 1 of the input shaft 12 is supported within the housing side wall 35.
a central hole 18 for receiving a bearing 16 therein;
Supported by

The output shaft 17 has a flange 19 carrying the planetary traction roller assembly 2. The traction roller assembly 2 is rotatably supported on a shaft 22 extending between an output shaft flange 19 disposed on one side of the planetary roller 21 and a support ring 23 disposed on the other side of the planetary roller 21. It includes a grooved planetary roller 21. The planetary roller 21 has a circumferential annular projection 24 shaped to fit within the groove 13 of the sun roller 1 for engagement of the side surface 14 with the side surface of the annular projection 24 of the planetary roller 21 .

The traction ring 32 of the traction ring assembly 3 has an annular axial cam region 38 opposite its side surface 33, and the housing side plates 34 and 35 have an annular axial cam projection 39, with the cam region 38 and the cam projection 39 A bearing roller 40 is disposed between and held in place by an annular cage 41 having circumferentially spaced openings for receiving the roller 40. To provide a torque-dependent engagement force, the traction ring 3
2 is movable in the circumferential direction to some extent by the reaction torque of the planetary roller 21 until it is firmly engaged with the planetary roller 21 by the cam structures 3B, 39. As a result, a portion of the planetary roller side surface engages between the traction rings 32 with an engagement force that depends on the torque transmitted via the transmission.

At the same time, the planetary rollers 21 are forced radially inward into tight engagement with the sun rollers 1.

Transmissions with hard surface contact areas that operate in traction fluid typically do not last very long when there is high shear in the contact area, as is the case in such channel configurations. However, such a transmission is relatively lightweight for the amount of power it can transmit. Furthermore, it has been found that the required part precision and manufacturing costs are fairly high, but are justified where weight savings are critical, such as in aircraft turbine reducers and space applications.

The necessary surface smoothness and precision of groove grinding can be achieved by modern lash grinding. The computer printout described below provides data for the first stage turbine speed reduction drive with three planetary rollers. However, any other number of rollers may be used as long as they can be accommodated. In the arrangement shown in FIGS. 1 and 2, four planetary traction rollers are used.

Furthermore, as shown in FIGS. 1 and 2, there are only two contact areas with the traction ring 32 for each planetary roller and four contact areas with the sun roller 1. Note that this is advantageous because the curvature difference between the traction ring 32 and the planetary rollers is substantially smaller than that between the sun roller and the planetary rollers. And the surface pressure between the traction ring and the sun roller is of similar magnitude, which can avoid undesirable slippage or other overloading of the sun roller surface.

FIG. 3 schematically shows an arrangement in which a countersunk ring 48 replaces the cam assembly as shown at 40 in FIG. These are simpler and lighter than cam assemblies, but provide only a certain amount of engagement force.

FIG. 4 shows a planetary traction roller transmission with grooved sun and planetary rollers according to the present invention, in which the engagement force is in principle determined by the
No. 941,004. In this arrangement, the traction ring 50 arranged in the housing 51 surrounds the three traction rollers 52, 53, 54;
These traction rollers include a sun roller 55 and a traction ring 50.
It engages with the sun roller 55 for power transmission between the two.

The sun roller 55 is part of the input shaft 56 and the traction ring is mounted on the output shaft 57 which is supported within the housing 51 by bearings 58. The axes of the sun roller 55 and the traction ring 50 are parallel to each other but offset by a distance d such that an annular passage of varying width is formed between the traction ring 50 and the sun roller 55. roller 52
are arranged in the widest passage area and rollers 53 and 54
are located in narrow passage areas. The roller 52 is rotatably supported on a shaft 59 extending between the housing 51 and the support ring 60. Both rollers 53.54 are free to move into the narrowing passage, but their movement out of this narrowing passage is limited, for example, by the larger roller 53.54 extending between the housing 51 and the support ring 60. It is defined by an abutment provided by the axis 61.62 passing through the opening 63.64 and adapted to be abutted by the roller as it moves in an outward direction from the narrowing gap. This arrangement causes all planetary rollers to be firmly engaged with the sun roller and traction ring when torque is transmitted through the transmission.

In the arrangement according to the invention, the radial force does not have to be large, i.e. it can be substantially smaller than in the case of cylindrical rollers, since the radial force is amplified as a contact force against the inclined side surface. This is because it will be done. Therefore, the bearing force is smaller and the bearing is smaller and lighter. On the other hand, the amplified contact force on the metal side of the roller groove does not have to be transmitted through the various parts and is compensated by other forces applied to the same part. For example, the axial component of the engagement force on one side 65 of the annular projection is compensated by the axial component of the engagement force on the adjacent side 66 of the same annular projection, so that only radial forces are applied by the housing, i.e., the traction ring. It should be absorbed by. Such a transmission therefore has a high power transmission capacity while having a relatively low weight.

[Brief explanation of drawings]

1 and 2 schematically show a planetary traction roller drive with torque-dependent engagement means, FIG. 2 a view taken along the line ll-Tl of FIG. 1, and FIG. Figures 4 and 5 show other embodiments with different roller and ring engagement means; FIG. , Figure 5 shows v-■ in Figure 4.
FIG. [Explanation of symbols of main parts] 1; 55...Sun roller 2; 52, 53
, 54... Traction roller 3... Traction ring assembly 12; 56... Input shaft 13... V groove 17; 57. ...Output shaft 21...Planetary roller 24...Annular protrusion 32:50...Traction ring 38... ...The cam area 40...Cam structure 48...Belleville type spring ring■" FIG, 4 FIG, 5

Claims (1)

Claims: 1. A first lubricated hard metal roller having at least axially spaced grooves with sloped radial sidewalls, and a first lubricated hard metal roller having axially spaced grooves with sloped radial sidewalls; a second lubricated hard metal roller having an annular protrusion with side walls; support means rotatably supporting said rollers in parallel and spaced apart relation; and rotational movement between said first and second rollers. means for forcing said rollers towards each other such that the sloped radial sidewalls of said groove engage the sloped sidewalls of said protrusion for the transmission of a traction roller transmission. 2. In claim 1, the radial contact length of the inclined side walls of the first and second rollers is not greater than 0.015 times the diameter of the smaller of the two rollers in contact with each other. Traction roller transmission. 3. a traction ring assembly having a traction ring with opposing conically inclined sides and a diameter smaller than said traction ring assembly centrally disposed within said traction ring assembly and defining an annular space therebetween; a sun roller having an annular groove with sloped sides forming a hard, lubricated traction race surface; supported in a space between the sun roller and the traction ring structure and engaged by the sides of the sun roller; a planetary traction roller having an annular protrusion with sloping sides extending into the groove of the sun roller so as to extend into the groove of the sun roller, the traction ring structures being arranged on opposite sides of the planetary roller and adjacent to the planetary roller; traction rings having conical sides and forcing said traction rings toward each other so as to firmly engage the conical surfaces of said traction rings with the outer ones of said slanted sides of the planetary rollers during operation of the transmission; a planetary traction roller transmission; 4. The transmission of claim 3, wherein the means for forcing the traction rings toward each other is an axial cam assembly formed adjacent to the traction rings to provide a reaction torque dependent engagement force. 5. Transmission according to claim 3, wherein the means for forcing the traction rings toward each other is a disc spring ring. 6. In claim 3, the radial contact length of the inclined surfaces of the sun roller and the planetary traction roller is 0.015 of the diameter of the smallest of the sun roller and the planetary traction roller. Traction roller transmission not larger than double. 7. input and output shafts and a hard metal traction ring carried by one of the shafts for rotation therewith;
carried by the other of said shafts in said traction ring, the axis of which is parallel to the axis of said traction ring but eccentric therefrom, forming an annular passage of varying width between said sun roller and said traction ring; and a plurality of hard metal motion transmitting planetary traction rollers disposed in annularly spaced relationship within the annular space, at least one of the planetary traction rollers disposed in the annular space. supported for free movement into a narrowed portion of the passageway to bring the planet roller into firm engagement with the sun roller and the traction ring, each of the sun roller, planet roller and traction ring having alternating annular protrusions. means with sloped sides, and at least some of the protrusions of the planetary rollers are connected to the sun such that the sloped sides are in power transmission engagement with each other when torque is transmitted through the transmission. a traction roller transmission extending into a roller and into a recess in said traction ring; 8. According to claim 7, the planetary traction roller has a traction roller whose traction side surfaces are smaller in number than those which are engaged with the sun roller and which are engaged with the traction ring. Machine. 9. Claim 7, wherein the radial contact length of the inclined surfaces of the sun roller and the planetary traction roller is 0.015 of the diameter of the smallest of the sun roller and the planetary traction roller. Traction roller transmission not larger than double.