CN112032258A

CN112032258A - Non-backlash stepped roller enveloping worm drive

Info

Publication number: CN112032258A
Application number: CN202010723315.4A
Authority: CN
Inventors: 陆彬彬; 陈永洪; 陈兵奎; 罗文军; 叶欣馨
Original assignee: Chongqing University
Current assignee: Chongqing University
Priority date: 2020-07-24
Filing date: 2020-07-24
Publication date: 2020-12-04

Abstract

The invention discloses a non-backlash stepped roller enveloping worm transmission, which belongs to the field of mechanical transmission and comprises a stepped roller, a gear blank, a mandrel and a worm wheel body, wherein the stepped roller is formed by installing an upper end roller and a lower end roller with different diameters on the same mandrel, the stepped roller is provided with a plurality of stepped rollers, the stepped rollers are uniformly distributed around the gear blank to form a stepped roller worm wheel, the cylindrical surfaces of the stepped rollers are enveloped to form a enveloping worm tooth surface according to a meshing motion relationship, one end of the mandrel is in threaded connection with the worm wheel body, the lower end roller comprises a first roller pin and a first outer ring, the first outer ring is sleeved on the outer wall of the first roller pin, the upper end roller comprises a second roller pin and a second outer ring, and the second outer ring is sleeved on the outer wall of the first. The invention has the advantages of high transmission efficiency, strong bearing capacity, high transmission precision, zero return difference, low noise and the like, and is suitable for the precision transmission fields of machine tool indexing tables, automatic production lines and the like.

Description

Non-backlash stepped roller enveloping worm drive

Technical Field

The invention belongs to the field of mechanical transmission, in particular to non-backlash stepped roller enveloping worm transmission.

Background

The worm transmission belongs to staggered shaft transmission, has the characteristics of compact structure, stable transmission, reverse self-locking, low noise, small motion error and the like, and is widely applied to the fields of aerospace, ship navigation, mine metallurgy, rail transit, national defense weapons and the like. The precision worm transmission is widely applied to the fields of machine tool indexing, instruments and meters, automatic production lines and the like due to the advantages of high precision, low return difference, error homogenization effect and the like. The current precision worm drive mainly comprises the following six types:

1) the worm is a cylindrical worm with the tooth surface of two sides having different modulus, the tooth thickness is gradually changed along the axis, and the worm wheel is processed by a corresponding compound modulus hob. The axial position of the worm is adjusted, and the tooth side clearance of the transmission pair or the abrasion loss of the compensation gear teeth can be adjusted. But the transmission has the defects of extremely small number of pairs of teeth meshed simultaneously, low bearing capacity, easy abrasion, short precision service life and the like.

2) The Wei's worm drive has its worm tooth surface formed by the generating motion of the meshing relation between worm wheel and worm with the positive plane as the mother plane, and the planar worm wheel is split along the central plane of tooth width. However, the transmission has the defects of easy undercut of tooth surfaces, poor rigidity of a worm gear structure, low bearing capacity and the like.

3) The OTT sectional type cylindrical worm transmission and Cone sectional type ring surface worm transmission are characterized in that a worm is composed of a half worm shaft and a half hollow worm, the tooth surface of a worm wheel is reasonably modified to adapt to the split design of the worm, the working surface of the two worms is in contact with the teeth of the worm wheel by rotating the hollow worm, a tooth side gap is set, and the two worms are fixedly connected by a tensioning sleeve. The transmission has the defects of less number of meshing teeth, poor rigidity of a worm structure, low bearing capacity and the like.

4) The variable tooth thickness gear with adjustable backlash is used for enveloping a toroidal worm for transmission, the inclination angles of tooth planes on two sides of the gear teeth of a worm gear are different, the gear teeth are wedge-shaped along the axial direction, the tooth surface of the worm is an enveloping surface taking the tooth surface of the variable tooth thickness gear as a mother surface, and the reasonable adjustment of all tooth backlash can be realized by axially shifting the variable tooth thickness gear. However, the transmission has the defects that the backlash adjustment, the abrasion compensation and the like cannot be accurately carried out.

5) The double-roller enveloping toroidal worm transmission without backlash is characterized in that a worm is a toroidal worm formed by primary enveloping by taking a worm gear tooth surface as an original mother surface, worm gear teeth are two rollers capable of rotating around the axes of the two rollers, and the adjustment of the backlash of a transmission pair and the compensation of the abrasion loss can be realized by adjusting the phase angle between the two rollers. But the transmission has the defects of smaller roller support shaft, poorer worm wheel rigidity, lower bearing capacity and the like.

6) The single roller enveloping ring surface worm drive without backlash, the worm wheel gear teeth of the worm drive are rollers, the ring surface worm gear tooth surface is an enveloping surface taking the roller cylindrical surface as a mother surface, and the ring surface worm gear tooth surface is simultaneously subjected to shape modification treatment, so that two sides of the middle gear tooth are not contacted, the left and right gear teeth are symmetrically meshed on one side, and one side transmits power and the other side eliminates return stroke difference in the running process. However, the transmission has the defects of less number of simultaneously engaged teeth, high shaping processing difficulty, low bearing capacity and the like.

In summary, the existing precision worm drive generally has the defects of low bearing capacity, high precision machining difficulty, difficult side clearance adjustment and the like.

Disclosure of Invention

The invention aims to overcome the defects in the precision worm drive and provides a backlash-free stepped roller enveloping ring surface worm drive.

The purpose of the invention is realized by the following technical scheme:

the side-clearance-free stepped roller enveloping worm transmission comprises stepped rollers, a gear blank, a core shaft and a worm wheel body, wherein the stepped rollers are formed by installing upper end rollers and lower end rollers with different diameters on the same core shaft, the stepped rollers are arranged in a plurality, the stepped rollers are uniformly distributed around the gear blank to form a stepped roller worm wheel, the cylindrical surfaces of the stepped rollers are enveloped according to a meshing motion relationship to form a enveloping worm tooth surface, one end of the core shaft is in threaded connection with the worm wheel body, the lower end rollers comprise first rolling needles and first outer rings, the first outer rings are sleeved on the outer walls of the first rolling needles, the upper end rollers comprise second rolling needles and second outer rings, and the second outer rings are sleeved on the outer walls of the first rolling needles.

Further, the diameter of the upper end roller is smaller than that of the lower end roller.

Furthermore, the stepped roller is fixedly arranged on the worm wheel body through the core shaft, so that the upper end roller and the lower end roller and the core shaft can rotate relative to each other through the first rolling needle and the second rolling needle.

Furthermore, the outer wall of the mandrel is sleeved with a gasket, and the gasket is located between the upper end roller and the lower end roller and respectively and independently rotates.

Furthermore, the stepped tooth surfaces on the two sides of the tooth surface of the enveloping worm are all subjected to whole tooth surface shaping.

Furthermore, the upper step surface of the tooth surface of the enveloping worm is subjected to interference modification, the corresponding lower step surface of the tooth surface of the enveloping worm is subjected to clearance modification, and the other side of the tooth surface of the enveloping worm is subjected to reverse interference modification.

Furthermore, the surfaces of the upper end roller and the lower end roller and the tooth surface of the enveloping worm are subjected to heat treatment by adopting high-hardness materials.

Compared with the prior art, the invention has the beneficial effects that:

the precision backlash-free stepped roller enveloping worm drive has the advantages of high drive efficiency, high bearing capacity, high drive precision, zero return difference, low noise and the like.

Drawings

FIG. 1 is a schematic structural view of the zero backlash stepped roller enveloping toroidal worm drive of the present invention;

FIG. 2 is a schematic view of the manner in which the rollers of the stepped roller worm gear of the present invention are mounted;

FIG. 3 is a schematic illustration of the upper roller enveloping toroid worm tooth flank modification principle of the present invention;

FIG. 4 is a schematic diagram of the flank modification principle of the lower roller enveloping worm of the present invention.

The labels in the figure are: 1. a worm gear body; 2. a lower end roller; 3. an upper end roller; 4. a roller enveloping a toroidal worm; 5. a first outer race; 6. a first needle roller; 7. a gasket; 8. a second outer race; 9. a second needle roller; 10. a mandrel; 11. a first actual tooth surface; 12. a second theoretical tooth surface; 13. a first theoretical toric worm flank; 14. a second actual tooth surface; 15. a third actual tooth surface; 16. a second theoretical toric worm flank; 17. a fourth actual tooth surface; 18. the third theoretical tooth surface.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

As shown in fig. 1-4, the backlash-free stepped roller enveloping worm drive comprises a stepped roller, a gear blank, a core shaft 10 and a worm gear body 1, wherein the stepped roller is formed by installing an upper end roller 3 and a lower end roller 2 with different diameters on the same core shaft 10, the stepped roller is provided with a plurality of stepped rollers, the plurality of stepped rollers are uniformly distributed around the gear blank to form a stepped roller worm gear, the cylindrical surfaces of the plurality of stepped rollers are enveloped to form a enveloping worm tooth surface according to a meshing motion relationship, one end of the core shaft 10 is in threaded connection with the worm gear body 1, the lower end roller 2 comprises a first roller pin 6 and a first outer ring 5, the first outer ring 5 is sleeved on the outer wall of the first roller pin 6, the upper end roller 3 comprises a second roller pin 9 and a second outer ring 8, the second outer ring 8 is sleeved on the outer wall of the first roller pin 6, the diameter of the upper end roller 3 is smaller than that of the lower end roller 2, the upper end roller 3, the lower end roller 2 and the mandrel 10 are enabled to rotate relatively through the first roller pin 6 and the second roller pin 9, the gasket 7 is sleeved on the outer wall of the mandrel 10 and located between the upper end roller 3 and the lower end roller 2, the stepped tooth surfaces on two sides of the tooth surface of the toroidal worm are all subjected to whole shape modification, the upper stepped surface of the tooth surface of the toroidal worm is subjected to interference shape modification, the corresponding lower stepped surface gap shape modification of the tooth surface of the toroidal worm is carried out, the other side of the tooth surface of the toroidal worm is subjected to reverse interference shape modification, the surfaces of the upper end roller 3 and the lower end roller 2 and the tooth surface of the toroidal worm are subjected to heat treatment by high-hardness materials, and.

The tooth surface of the roller enveloping toroidal worm 4 is subjected to shape modification treatment, at the position of 2-1, the depth of a bd section outwards modified along the tooth surface normal direction on the basis of the worm tooth surface of a second theoretical tooth surface 12 enables a first actual tooth surface 11 on one side to generate normal interference with the worm wheel lower end roller 2, and the depth of a ce section inwards modified along the tooth surface normal direction on the basis of a first theoretical toroidal worm tooth surface 13 on the other side enables a second actual tooth surface 14 on the other side to generate a normal gap with the worm wheel lower end roller 2. And the section ab and the section df of the second theoretical tooth surface 12 are subjected to reverse slope modification, and the section ac and the section ef of the first theoretical ring surface worm tooth surface 13 are subjected to reverse slope modification, so that the meshing process of the first actual tooth surface 11 and the second actual tooth surface 14 with the lower end roller 2 is more stable, and the vibration and the noise during the operation are reduced. At the 2-2 position, the BD segment is inwardly trimmed to a depth along the normal to the tooth surface on the basis of the second theoretical toric worm tooth surface 16, so that the third actual tooth surface 15 on the one side is normally spaced from the upper end roller 3, and the CE segment is outwardly trimmed to a depth along the normal to the tooth surface on the basis of the third theoretical tooth surface 18 on the other side, so that the fourth actual tooth surface 17 on the other side is normally in interference with the upper end roller 3. The reverse slope modification is carried out on the AB section and the DF section of the second theoretical ring surface worm tooth surface 16, the reverse slope modification is continued on the AC section and the EF section of the third theoretical ring surface worm tooth surface 18, so that the engaging and disengaging process of the third actual tooth surface 15 and the fourth actual tooth surface 17 and the upper end roller 3 is more stable, and the vibration and noise during the operation are reduced.

The present invention is not limited to the above preferred embodiments, and any modifications, equivalent substitutions and improvements made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. The side-clearance-free worm transmission with the stepped roller and the enveloping ring surface comprises a stepped roller, a gear blank, a mandrel and a worm wheel body, and is characterized in that: the stepped rollers are formed by installing upper end rollers and lower end rollers with different diameters on the same mandrel, the stepped rollers are arranged in multiple numbers, the stepped rollers are uniformly distributed around a gear blank to form a stepped roller worm gear, the cylindrical surfaces of the stepped rollers are enveloped according to a meshing motion relationship to form a ring-surface worm tooth surface, one end of the mandrel is in threaded connection with the worm gear body, the lower end rollers comprise first roller pins and first outer rings, the first outer rings are sleeved on the outer walls of the first roller pins, the upper end rollers comprise second roller pins and second outer rings, and the second outer rings are sleeved on the outer walls of the first roller pins.

2. The backlash free stepped roller enveloping toroidal worm drive of claim 1, wherein: the diameter of the upper end roller is smaller than that of the lower end roller.

3. The backlash free stepped roller enveloping toroidal worm drive of claim 1, wherein: the stepped rollers are fixedly arranged on the worm wheel body through the core shaft.

4. The backlash free stepped roller enveloping toroidal worm drive of claim 1, wherein: the outer wall of the mandrel is sleeved with a gasket, and the gasket is located between the upper end roller and the lower end roller.

5. The backlash free stepped roller enveloping toroidal worm drive of claim 1, wherein: and the stepped tooth surfaces on the two sides of the tooth surface of the enveloping worm are all integrally shaped.

6. The backlash free stepped roller enveloping toroidal worm drive of claim 1, wherein: the upper step surface of the tooth surface of the enveloping worm is subjected to interference modification, the corresponding lower step surface of the tooth surface of the enveloping worm is subjected to clearance modification, and the other side of the tooth surface of the enveloping worm is subjected to reverse interference modification.

7. The backlash free stepped roller enveloping toroidal worm drive of claim 1, wherein: the surfaces of the upper end roller and the lower end roller and the tooth surface of the enveloping worm are subjected to heat treatment by adopting high-hardness materials.