RU2564556C1 - Two-stage cone waveform gear unit - Google Patents

Abstract

FIELD: machine building.

SUBSTANCE: small-scale two-stage waveform gear unit contains a crank shaft, output shaft, external, internal, casing and cone wheel of the output shaft. The crank shaft is made stepped, and has two coaxial spread support surfaces, on which two ball bearings are installed coaxially. Two other ball bearings are installed in assembly unit, and on the output shaft. On the inclined part of the crank shaft the wobbly gear is installed, it is made as assembly unit, comprising two cone wheels, rigidly connected with each other such that their toothed rims are located at the same side of the unit. On wheels being part of the same interacting pair different number of teeth is made.

EFFECT: reduced overall dimensions of the gear box, and cantilever load on both shafts.

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Description

The invention relates to mechanical engineering and can find application in various mechanisms of control system devices, optical-mechanical devices as kinematic and power drives, and other devices that require the conversion of torque with a large gear ratio and small dimensions.

The prior art analogues are known: patent RU 2085786 from 02.21.1995, and copyright certificate SU 200382 from 01.01.1967

RU 2085786 describes a rotation gear comprising a housing, coaxially mounted drive and driven shafts mounted therein, two gear wheels interacting with each other, one of which is coaxially with the shafts and fixedly mounted relative to the housing, the other is mounted obliquely to the axis of the shafts and connected to the driven shaft by means of a spherical support. The source of movement is a carrier in contact with the end surface of an inclined wheel. The transmission is equipped with an additional gear wheel, integral with the driven shaft, the gear wheel mounted obliquely, made with two crowns, and its end surface is conical, while the drive shaft is connected to the compressed air line, made hollow and serves as the axis of the pneumatic turbine, with the possibility of longitudinal of movement, the driven shaft from one end is made in the form of a stepped hub and a blind hole is made along its axis, and the carrier includes a disk interacting with a pneumatic tube and mounted on an axis, Bodnya installed in a bore of the driven shaft, a sleeve mounted on the hub of the driven shaft and a roller, connected to the sleeve via a lead pivotally mounted thereon.

The disadvantages of such a transfer are:

1) technological difficulties in the manufacture of an additional two-crowned wheel with a different number of teeth on the inner and outer rims,

2) the impossibility of using such a transmission in kinematic chains with mechanical connections (without using a pneumatic drive),

3) lack of irreversibility and self-braking in the transmission,

4) the impossibility of obtaining large gear ratios without increasing the size of the gears by combining the number of teeth on different wheels.

Certificate SU 200382 describes a planetary gear reducer with bevel wheels for transmitting movement to a sealed space containing a satellite mounted obliquely on the drive shaft and making a precession movement, a driven wheel that is rigidly connected to the driven shaft and engages with the satellite, a flexible membrane, connecting the satellite to the housing and dividing the gearbox into two cavities isolated from each other. The satellite is equipped with an additional gear rim engaging with the rim of the fixed casing wheel. On the satellite and the casing wheel the same number of teeth is made.

The disadvantage of this gearbox is the presence of a membrane that does not allow to realize a two-stage mode of operation in this design, without making significant changes to it.

The prototype is a single-stage bevel wave reducer, a description of which is given in a publicly available literature (Prince Pavlov BI, Mechanisms of Instruments and Control Systems. Leningrad. 1972, p. 168, Fig. 91). A single-stage bevel wave reducer is designed to transmit rotation into a sealed space.

In a bevel wave gearbox, an inclined crank roller is used, on which a block of two bevel wheels is mounted, which vibrates without rotation in a plane perpendicular to the axis of the input and output rollers. One of these bevel wheels is driving and engages with a bevel wheel transmitting movement to the driven roller. The second wheel of this block engages with a fixed gear wheel having the same number of teeth and made in one piece with the gear housing cover. The bellows diaphragm in the design is used to distinguish the atmospheric pressure zone from the vacuum and is passive, since it does not absorb the load from the torque.

The disadvantages of this design are the inability to operate as a two-stage bevel wave reducer due to the use of a diaphragm-bellows, which does not allow a precessing movement to a block of two bevel wheels and creates a pulsation of torque on the output shaft, which leads to a deterioration in the accuracy characteristics of the entire device, in which uses this wave gear.

The objective of the invention is the creation of a gearbox with a large gear ratio, operating in a two-stage mode, with small overall dimensions, reducing the cantilever load on both shafts, as well as reducing the number of incoming parts and achieving high manufacturability.

The task is achieved due to the fact that bulky elements are excluded from the design of the device. The gearbox is based on the principle of a two-stage bevel wave transmission with rigid links, in which, to obtain the minimum axial overall dimension, two pairs of interacting bevel gears are mounted with gear profiles facing each other, as well as using a different crank shaft and fewer ball bearings.

In fig. 1 shows a two-stage bevel wave gear:

1 - cover;

2 - conical case wheel;

3 - external conical wheel;

4 - inner conical wheel;

5 - output shaft with a bevel wheel;

6 - crank shaft;

7 - a casing;

8 - base.

A small two-stage bevel wave reducer contains a housing consisting of a casing (7) and a base (8), in which a crank shaft (6), which is the drive shaft, and an output shaft (5), which is driven, are installed coaxially. The crank shaft (6) is stepped and has two coaxial spaced bearing surfaces on which two ball bearings are mounted coaxially, acting as a support for the crank shaft and reducing the cantilever load on both shafts, while two other ball bearings are installed in the assembly block and on the output shaft. On the inclined part of the crank shaft (6), a swing gear is installed, made in the form of an assembly block consisting of external (3) and internal (4) bevel wheels rigidly interconnected so that their gear rims are located on one side of the block and the external the bevel wheel (3) was engaged with the bevel wheel (2) fixedly mounted on the housing, and the inner bevel wheel (4) was engaged with the bevel wheel of the output shaft (5). On bevel wheels included in one interacting pair, a different number of teeth is performed. A cover (1) is mounted on the bevel wheel (2) to regulate the axial tension of ball bearings.

From a comparison of the design of the prototype with the design of the new gearbox proposed for protection as an invention, the following differences were identified:

1. The new gearbox has smaller dimensions: 32 mm in diameter and 32 mm in length, while the approximate size of the prototype is at least 150 mm in length, which is definitely the type of spherical ball bearing mounted in a block of two bevel wheels.

2. The reduction in size is achieved by eliminating the bellows diaphragm from the design, which also made it possible to freely precess the movement of the assembly unit relative to the point of coincidence of the vertices of the pitch cones of the bevel wheels.

3. In the new gearbox, the crank shaft is made stepwise, and in the prototype of the crank shaft, the inclined part is made cantilever.

4. The prototype uses seven bearings.

To support the crank shaft, two radial and one spherical ball bearing are used, two radial ball bearings are pressed into the housing, and the spherical ball bearing is mounted in a block of two bevel wheels, which also supports the output shaft.

The output shaft is mounted on one angular contact tapered roller bearing and one radial ball bearing.

The assembly block is mounted on two deep groove ball bearings.

The new gearbox uses only four ball bearings of radial type.

As a support for the crank shaft, two coaxial, spaced bearing surfaces are used on which two ball bearings are coaxially mounted, while two other ball bearings are installed in the assembly unit and on the output shaft.

This arrangement, the number and type of ball bearings made it possible to reduce the size of the gearbox and reduce the cantilever load acting on both shafts, which in turn leads to increased reliability, increased service life, reduced size and weight of the gearbox.

5. In the new gearbox on bevel wheels included in one interacting pair, a different number of teeth is performed, which allows for a two-stage operation mode.

When the crank shaft (6) rotates, the assembly block begins to precessively move relative to the coincidence point of the vertices of the pitch cones of the bevel wheels by rolling the teeth of the outer bevel wheel (3) along the teeth of the bevel wheel (2). Engaged simultaneously by the teeth of the inner bevel wheel (4) with the ring gear of the bevel wheel of the output shaft (5), the assembly unit transmits rotation to the output shaft.

The technical result of the invention is to reduce the overall dimensions of the gearbox and the cantilever load on both shafts when implementing a two-stage mode of operation with a large gear ratio and high adaptability to production.

Claims (1)

A two-stage bevel wave reducer, comprising two coaxially mounted shaft housings, a crank and an output one, is driven by a crank shaft, on the inclined part of which a swing gear is mounted, made in the form of an assembly block consisting of external and internal bevel wheels rigidly interconnected in such a way so that their gear rims are located on one side of the block and the outer conical wheel engages with the conical wheel fixedly mounted on the housing, and the inner conic the gear wheel was engaged with the bevel wheel of the output shaft, characterized in that for the implementation of the two-stage operation mode on the bevel wheels included in one interacting pair, a different number of teeth is performed, the crank shaft is stepped and has two coaxial spaced bearing surfaces on which are mounted coaxially two ball bearings that act as a support for the crank shaft, while two other ball bearings are installed in the assembly block and on the output shaft.