CN110259915B

CN110259915B - Speed change device capable of eliminating transmission clearance and clearance eliminating method thereof

Info

Publication number: CN110259915B
Application number: CN201910520416.9A
Authority: CN
Inventors: 邓星桥
Original assignee: Chengdu Zhongliangchuangong Technology Co ltd
Current assignee: Chengdu Zhongliangchuangong Technology Co ltd
Priority date: 2019-06-14
Filing date: 2019-06-14
Publication date: 2021-05-25
Anticipated expiration: 2039-06-14
Also published as: CN110259915A

Abstract

The invention relates to a speed change device capable of eliminating transmission clearance and a clearance eliminating method thereof, wherein the speed change device at least comprises a worm and a worm wheel which are arranged in a box body and have different axial surfaces, the worm wheel is provided with detachable worm teeth which can be mutually jointed with a worm channel of the worm along the circumferential direction at intervals, the worm wheel comprises at least two disks which are mutually attached in the axial direction, the radial outer sides of the at least two disks are respectively provided with rolling bodies which are arranged at intervals along the circumferential direction, under the condition that the worm and/or the worm wheel rotate around the axial line of the worm wheel, the worm channel at any moment is jointed with the worm teeth which are limited by the rolling bodies which are adjacent to each other in the axial direction of the at least two disks and have included angles, the rolling bodies of the worm teeth positioned at two sides of the worm axial line are always in line contact with the tooth surfaces at two sides of the worm channel in a mode that the included angles can be adjusted, and the axial center Respectively rotate.

Description

Speed change device capable of eliminating transmission clearance and clearance eliminating method thereof

Technical Field

The invention relates to the technical field of mechanical transmission, in particular to a speed change device capable of eliminating transmission gaps and a gap eliminating method thereof.

Background

The worm transmission is used in the occasions where two shafts are staggered, the transmission ratio is large, the transmission power is not too large or the transmission works intermittently, and the worm transmission is often applied to a speed changer as an important transmission mode in mechanical transmission due to the advantages of stable transmission, low noise, small impact load, self-locking property and the like. However, in order to form a lubricating oil film between the tooth profiles of the meshing worm gear and avoid the gear teeth from being blocked due to frictional heating and expansion, a clearance is required to be left between two non-working tooth profiles of the conjugate teeth, and the clearance is called a tooth side clearance, which is called a backlash for short. This backlash is normally used to store lubricating oil and to compensate for thermal variations, elastic deformations, manufacturing and mounting errors, etc. which occur in the drive in order to ensure proper meshing of the worm gear and the drive. However, in a transmission requiring forward and reverse rotation, the presence of backlash causes backlash shock and affects the smoothness of the gear transmission.

In addition, the ordinary worm transmission is easy to wear in the transmission process, and the reason is that the relative movement speed of the transmission pair at the conjugate tooth surface is always greater than the circumferential speed of the worm or the circumferential speed of the worm wheel, so that the relative speed of the contact point at any position is not zero and is always in a sliding friction state, namely, the meshing gears have a larger relative sliding speed, so that the wear, the heat and the energy consumption of the tooth surface can be caused, and the friction loss power of the ordinary worm transmission is large, the transmission efficiency is low, the tooth surface is quickly worn, and the precision life is short. And after the abrasion, gaps exist among the tooth surfaces of the worm and gear or the gaps are increased, so that the transmission precision and the transmission stability are influenced, and the transmission failure can be caused in severe cases.

Therefore, the defects make the common worm difficult to meet the requirements of high-precision and high-efficiency transmission in modern industry. The engagement backlash in the ordinary worm drive inevitably brings the problems of impact, vibration and noise, and reduces the follow-up precision and stability of the system, and especially in the worm drive speed changing device which needs frequent forward and reverse rotation, the existence of the engagement backlash can cause larger accumulated errors, and the transmission precision, the position precision and the dynamic response characteristic of the whole device are seriously influenced.

Therefore, the prior art has proposed a great deal of improvement method and structure for the problem of backlash and sliding friction in the worm drive, for example, chinese patent publication No. CN109764113A discloses a backlash adjustable rotary speed reducer. The traditional rotary speed reducer has errors in the manufacturing and assembling process, and gaps exist between worn worm and gear teeth. The device comprises a base, an angular contact bearing, a worm shaft, a gradually-changed helical gear, a steel ball plug, a plug pin, a steel ball inner shaft, a worm shaft adjusting screw and a bearing metal sleeve; the displacement coefficient of the gradient helical gear is gradually changed along the axial direction; the worm shaft can be adjusted along the radial direction of the worm shaft through adjusting the worm shaft adjusting screw. The invention not only reduces the installation difficulty of the worm gear and worm rotary speed reducer, but also can achieve ideal meshing clearance through adjustment and improve the assembly quality; and can keep higher precision normal operating through the mode of adjustment backlash after the slewing reducer wearing and tearing, greatly prolonged slewing reducer's guarantee precision life-span, can promote slewing reducer to use widely greatly. The adjustable clearance's that this patent discloses rotary reducer is the volume of reducing of adjusting driven flank clearance in order to compensate the teeth of a cogwheel wearing and tearing through the axial position of adjustment worm, however, needs modulus hobbing cutter relief grinding and precision manufacturing difficulty during processing worm wheel, and when worm wheel and worm meshing transmission, the number of teeth of contact is few simultaneously, and bearing capacity is low, easy wearing and tearing, and the precision life-span is short, and precision manufacturing is with high costs, is difficult to satisfy high-speed precision transmission or heavily carry precision transmission's requirement.

For example, chinese patent publication No. CN208665301U discloses a novel clearance compensation mechanism for an electric power steering system, where the electric power steering system includes a housing, and a worm wheel and a worm that are engaged with each other, the upper end of the worm is driven by a motor to rotate, the clearance compensation mechanism includes a self-aligning bearing fixedly sleeved on the upper end of the worm, and a clearance compensation assembly disposed on the lower end of the worm; the clearance compensation assembly comprises an eccentric body and a bearing, the bearing is fixedly sleeved on the worm wheel, the eccentric body is fixedly sleeved on the bearing, a groove is formed in the outer circumference of the eccentric body, an O-shaped ring is sleeved on the eccentric body through the groove, the clearance compensation assembly is located in a containing groove formed in the shell, the O-shaped ring is attached to the inner wall of the containing groove, and the circle center of the inner circumference of the eccentric body is closer to the worm wheel than the circle center of the outer circumference of the eccentric body. The eccentric body provides a radial force which is deflected to the meshing position of the worm gear to the lower end of the worm, and the radial force can push the worm to the meshing position, so that the clearance between the worm gear and the worm is eliminated; the O-shaped ring is flexibly connected with the shell, so that abnormal sound generated by collision at the position can be completely eliminated. However, the clearance compensation device provided in this patent also has a high requirement for compensating the radial force of the clearance on the tooth side of the transmission by adjusting the axial position of the worm, and when the radial force is small, the worm cannot be pushed to the meshing point position, and when the radial force is large, the wear between the worm wheel groove of the worm and the worm wheel tooth of the worm wheel is increased, and when the worm teeth of a plurality of worm wheels mesh with the worm wheel groove of the worm, the clearance between the teeth of each worm wheel may be different, and adjusting the axial position of the worm may cause a clearance to exist between the other worm wheel teeth and the worm wheel groove, which makes it difficult to meet the requirement of precision transmission.

For example, chinese patent publication No. CN208634321U discloses a precision worm gear and worm pair backlash eliminating device, which includes two half worm gears axially connected with a socket head cap screw through a threaded hole on a wedge, and a top block having a compression spring mounted thereon for positioning with the wedge hole. During installation, the adjusting screw is fed to enable the wedge block to axially displace along a wedge opening on the worm wheel, and meanwhile, the pressure spring can be extruded to generate elastic force along the axial direction of the spring to drive the worm wheel to rotate for a certain angle, so that tooth surfaces of the two worm wheels are respectively in stress contact with the worm, and therefore transmission gaps in a precise worm-gear worm pair are eliminated. The utility model discloses a structure space utilization that adopts is high, simple structure, with low costs, realizes easily. However, the backlash eliminating device provided in this patent employs a staggered backlash, in which the worm teeth of the two half-worms are in simultaneous contact with the left and right tooth surfaces of the worm, respectively, and the relative sliding speed between the tooth surfaces of the worm is high, so that the tooth surfaces are easily worn, and the transmission efficiency is low.

For example, chinese patent publication No. CN108799477A discloses a worm and gear backlash adjusting mechanism, a speed reducing mechanism, and an automobile, wherein the worm and gear backlash adjusting mechanism includes: an outer ring; the inner ring of the open ring and the inner ring have a gap in the radial direction, the outer surface of the inner ring is fixedly connected with the inner surface of the outer ring, and an elastic element capable of generating radial pressing force is arranged between the inner ring and the outer ring; the first bulge is made of elastic materials and arranged on the inner surface of the outer ring, and the first bulge is close to the opening of the inner ring; and the second bulge is made of elastic materials, is arranged on the outer surface of the inner ring, is opposite to the first bulge and has a gap in the radial direction. However, the worm and gear meshing gap adjusting mechanism provided in the patent does not take into account that after the wear of the tooth space, the gap existing between the worm gear of the worm wheel and the tooth surfaces on the left and right sides of the worm cannot be eliminated by changing the relative distance between the worm and the worm wheel, so that the device provided in the patent cannot eliminate the impact between the worm gear and the tooth surfaces on the two sides of the worm in the transmission of positive and negative rotation of the worm and gear, which affects the stability in the transmission.

For example, chinese patent publication No. CN208602557U discloses a steering system power assisting device with adjustable gap, which includes a housing, a motor, and a worm gear and a worm that are engaged with each other; one end of the worm is connected with an output shaft of the motor, and the other end of the worm is arranged in the shell through a first bearing; the shell is provided with a mounting hole, and the first bearing is positioned in the mounting hole; an adjusting mechanism is arranged on one side of the shell opposite to the worm wheel and comprises a compression spring and an adjusting bolt; one end of the compression spring is abutted against the outer ring of the first bearing, and the other end of the compression spring is abutted against the adjusting bolt; under the action of the adjusting bolt and the compression spring, the worm and the worm wheel are tightly attached together. The utility model discloses can eliminate the clearance between the worm gear through the position of adjusting bearing, avoid the trouble that the renewal part brought, reduce the cost of maintenance of car to eliminate the noise that produces because of the clearance between worm gear and the worm, promoted user's driving comfort. The utility model discloses a clearance adjustable steering system assistant device, because the relative distance who adopts adjustment worm and worm wheel eliminates the clearance between worm and the worm wheel, when nevertheless not considering worm wheel and worm meshing, clearance between two flank of tooth of worm tooth and worm.

For example, chinese patent publication No. CN109322979A discloses a device for eliminating a worm gear drive gap. Wherein, the device includes: casing, front end housing, unsteady worm subassembly, bevel pinion, worm wheel, adjusting washer, spring, tegillum, wherein: the small bevel gear is used for transmitting the power of the motor to a bevel gear in the floating worm assembly; the bevel gear is connected with the worm through a flat key, and power is transmitted to the worm gear through the worm; the worm wheel is arranged in a bearing chamber of the shell and a bearing chamber of the front end cover which are positioned on the same axial line through bearings, and a circular hole is formed in the lower part of the shell and communicated with the cavity; the spring is arranged in the round hole of the small cover and is pressed against the floating worm assembly through the round hole, and the quantity of the gaskets is adjusted to ensure that the spring has certain pretightening force, so that the worm in the floating worm assembly is tightly attached to the tooth-shaped surface of the worm wheel. The embodiment of the invention can reduce and eliminate the return error of worm gear transmission, improve the output precision of the worm gear and meet the precision output requirement of the aviation rotary actuator. However, the device provided in this patent uses a floating worm, i.e. the axial position of the worm is also adjusted to achieve clearance elimination, which is poor in load-bearing capacity, prone to wear due to relative sliding friction between the tooth flanks, short in precision life, and difficult to precision manufacture.

For example, chinese patent publication No. CN109163084A discloses an automatic backlash eliminating worm gear and worm structure, and a processing method and a backlash eliminating method thereof, including a worm gear and a worm, the worm gear and the worm being matched with each other; the worm comprises a worm shaft, a worm sleeve, a spring, a compression nut and a locking nut; the worm shaft is connected with the worm sleeve through a spline, and the worm shaft is fixed with one end of the worm sleeve through the compression nut and the locking nut. However, the automatic backlash eliminating worm gear structure and the backlash eliminating method provided by the patent essentially change the axial position of the worm by using the spring, the worm teeth of the worm gear are always kept in contact with the tooth surfaces on both sides based on the elastic force of the spring, and the pressure between the worm teeth and the tooth surfaces on both sides of the worm is increased, so that the relative sliding friction between the worm teeth and the tooth surfaces on both sides is increased, the abrasion of the tooth surfaces is further increased, and the precision life of the device is shortened.

For example, chinese patent publication No. CN101598212B discloses a mechanism for automatically eliminating backlash, which includes a slider, a swing block, a spring seat, and a bearing surface I and a bearing surface II respectively disposed on the bearing surfaces of the fixed gear and the movable gear spokes which are installed in a coaxial line in a staggered manner; the bottom surface of the slide block and a bearing surface I arranged on a spoke of the fixed gear form a moving pair; the base ground of the swing block and the top surface (inclined surface) of the sliding block form a sliding pair; the swing head part of the swing block is positioned in the arc-shaped groove on the movable gear spoke and forms a revolute pair with the bearing surface II; the spring seat is installed on a spoke of the fixed gear, the central line of the spring seat is parallel to a bearing surface I arranged on the spoke of the fixed gear, one end of the spring is installed on the spring seat, and the other end of the spring is in contact with the side face of the sliding block. The automatic first-out tooth side clearance mechanism has the advantages of high bearing capacity, high reliability, simple structure and convenience in processing and manufacturing. However, the mechanism for automatically eliminating the backlash provided by the patent does not adopt the contact of rolling worm teeth and the tooth surfaces at two sides of the worm, so that the worm teeth and the tooth surfaces at two sides of the worm are in relative sliding friction, the tooth surface loss is large, and the precision life is low; and because the transmission elements are many, the volume is large, the structure is complicated, the transmission device is difficult to be suitable for the transmission device of the servo drive system which requires high transmission precision, large bearing capacity and compact mechanism, and the backlash generated by the abrasion of the tooth surface can not be automatically eliminated because of low meshing efficiency of some transmissions, so that zero-clearance transmission can not be really realized.

For example, chinese patent publication No. CN101290042A discloses a backlash-free double-roller enveloping worm gear transmission mechanism, which includes a double-roller enveloping worm gear and a worm gear composed of two half worm gears with rollers uniformly distributed in the radial direction, the rollers are uniformly distributed in the circumferential direction of each half worm gear, a single gear tooth of the worm gear is two rollers, the rollers can rotate around their own axes, and the double rows of rollers of the worm gear body are arranged in a staggered manner, wherein one row of rollers is meshed with the left side tooth surface of the worm, the other row of rollers is meshed with the right side tooth surface of the worm, the left and right tooth surfaces of the worm are respectively enveloped by the rollers located above and below the principal plane, and the installation positions of the two half worm gear bodies are adjusted by bolts, so that the double-roller teeth of the worm gear are always kept in contact with the left and right side tooth. However, in the double-roller enveloping worm gear transmission mechanism provided by the patent, the contact between the roller and the worm gear is axial, but is actually point contact in the moving direction, and in the structure of the technical scheme, in the moving process, particularly in the transmission process of the speed changing device, instantaneous rigid impact may occur, certain jumping is bound to exist, and zero-clearance transmission cannot be really realized.

In view of the deficiencies of the prior art, there is a need for a new worm drive transmission having zero backlash and slow flank wear, and preferably one that automatically eliminates backlash caused by flank wear.

Furthermore, on the one hand, due to the differences in understanding to the person skilled in the art; on the other hand, since the inventor has studied a lot of documents and patents when making the present invention, but the space is not limited to the details and contents listed in the above, however, the present invention is by no means free of the features of the prior art, but the present invention has been provided with all the features of the prior art, and the applicant reserves the right to increase the related prior art in the background.

Disclosure of Invention

The invention provides a speed change device capable of eliminating transmission clearance, aiming at the defects that the existing structure for eliminating the gear clearance is difficult to be applied to a transmission device of a servo drive system which requires high transmission precision, large bearing capacity and compact mechanism due to the fact that a plurality of transmission elements are arranged, and the structure is complex.

A speed variator able to eliminate drive gap is composed of a casing, a worm and a worm wheel arranged in the casing and having different axial surfaces. The worm wheel is provided with detachable worm teeth which are arranged along the circumferential direction at intervals and can be mutually jointed with the worm channel of the worm. The worm wheel comprises at least two disks which are attached to each other in the axial direction, rolling bodies which are arranged at intervals along the circumferential direction are arranged on the radial outer sides of the at least two disks respectively, and under the condition that the worm and/or the worm wheel rotate around the axis of the worm wheel, the worm channel at any moment is engaged with the worm teeth which are defined by the rolling bodies which are adjacent to each other in the axial direction of the at least two disks and have included angles. The rolling bodies of the worm teeth positioned at two sides of the worm axis are in line contact with the tooth surfaces at two sides of the worm channel all the time in a manner of adjusting the included angle, and the axes connecting lines between every two rolling bodies are intersected with the axis of the worm in a non-vertical manner. The angle is formed between the axes of two circumferentially adjacent rolling bodies on different discs.

According to a preferred embodiment, the worm teeth comprise at least a first rolling element and a second rolling element arranged at a distance from each other in the axial direction of the worm wheel. Under the condition that the worm wheel rotates around the axis of the worm wheel along the first direction or the second direction, at least one worm tooth is engaged with the worm channel, so that the first rolling body and the second rolling body are respectively in line contact with tooth surfaces on two sides of the worm channel, and the axial connecting line of the first rolling body and the second rolling body keeps unchanged in length, so that the worm tooth and the worm channel form relative rolling friction to realize gapless transmission of the worm wheel and the worm.

According to a preferred embodiment, in the case where the worm rotates about its axis and at least two of the worm teeth engage with the worm wheel, a first tangential force and a first radial force are applied to a first rolling body defining the worm tooth by the first rolling body contacting with a first tooth face of the worm wheel. Applying a second tangential force to a second rolling element defining the worm tooth in the same direction as the first tangential force and a second radial force opposite the first radial force by the second rolling element contacting a second flank of the worm gear. The first tangential force drives the first rolling body to rotate around the axis of the first rolling body through rolling friction between the first rolling body and the first tooth surface. The second tangential force drives the second rolling body to rotate around the axis of the second rolling body through rolling friction between the second rolling body and the second tooth surface. The worm wheel rotates about its axis by the first radial force transmitted by the first rolling elements and by the second radial force transmitted by the second rolling elements.

According to a preferred embodiment, in the case that the worm rotates around its axis and the first radial force is greater than the second radial force, the worm teeth drive the worm wheel to rotate around the axis of the worm wheel in the direction of the first radial force by the first radial force and the second radial force in opposite directions. The first rolling element rotates around its axis at a greater angular velocity than the second rolling rotation by a first tangential force greater than the second tangential force.

According to a preferred embodiment, in the case that the worm rotates around its axis and the first radial force is smaller than the second radial force, the worm teeth drive the worm wheel to rotate around the axis of the worm wheel in the direction of the second radial force by the first radial force and the second radial force in opposite directions. The first rolling element rotates around its axis at an angular velocity smaller than the second rolling rotation by a first tangential force smaller than the second tangential force.

A speed variator is composed of a casing, a worm and a worm wheel arranged in the casing and having different axial planes. The worm wheel is provided with detachable worm teeth which are arranged along the circumferential direction at intervals and can be mutually jointed with the worm channel of the worm. The worm way at any instant engages with the worm teeth defined by at least two rolling bodies in case the worm and/or worm wheel rotates around its axis. The rolling bodies, which are respectively in at least partial line contact with the tooth surfaces on the two sides of the worm way, rotate around respective axes in a mode of always rotating in opposite directions.

A method of eliminating backlash comprising eliminating backlash between a worm gear and a worm way of a transmission according to one of the preferred embodiments described above.

The beneficial technical effects of the invention comprise one or more of the following:

1. compared with the gapless transmission structure in the prior art, the worm gear is formed by the worm teeth limited by the at least two rolling bodies which are staggered with each other on the axis and the circumference of the worm gear, and at least one rolling body is abutted to each of the two side tooth surfaces of the worm channel in the transmission process, so that the transmission without tooth side gaps can be realized, the return error is eliminated, the impact caused by the tooth side gaps can be avoided at the moment of switching the rotation direction of the worm gear, and the abrasion between the teeth is reduced;

2. the speed change device provided by the invention forces at least two rolling bodies of the worm gear to be always attached to tooth surfaces at two sides of a worm way by the aid of the elastic force of the elastic body through two disks which are axially attached and can rotate relative to each other, namely, under the condition that a tooth side gap exists between the worm gear and the worm way due to abrasion or other impact, the included angle between the two rolling bodies of the worm gear can be changed by the elastic body, so that the worm gear and the worm way are always in a bidirectional zero-gap state in the transmission process, and the speed change device is always ensured to be in zero-gap transmission;

3. in the transmission process of the speed changing device, instant rigid impact can occur to cause the gap between teeth to appear or impact the worm gear to cause worm gear abrasion, the worm gear is composed of two rolling bodies with changeable included angles, and the impact born by the rolling bodies is absorbed by an elastic body and slowly released at the moment of impact, so that the damage of the impact on the rolling bodies is reduced, and the precision life is prolonged.

4. The speed change device provided by the invention can keep gapless transmission, and simultaneously utilize the two half worm gears to pass through a plurality of elliptical screw holes in the axial direction and connect the two half worm gears by using the bolts, so that the position between two rolling bodies of the worm gear is adjusted by the friction between the bolts to achieve the function of automatically eliminating the gap, and the function of automatically eliminating the tooth side gap is realized while the gapless transmission is realized;

5. according to the speed change device provided by the invention, the clearance between the two rolling bodies in the worm gear and the tooth surface of the worm channel is adjusted through the friction between the bolts, the structure is simple and compact, and the kinematic pair between the two half worm gears is a low pair, so that the speed change device is convenient to process and manufacture and low in cost;

6. in the transmission process, the two rolling bodies are always in line contact with the tooth surfaces on two sides of the worm channel, so that the relative sliding friction between the tooth surfaces is converted into the relative rolling friction, the abrasion between teeth can be further reduced, the problem of tooth side clearance caused by the abrasion of the tooth surfaces can be reduced, the transmission stability and the transmission efficiency are improved, and the precision life is prolonged.

7. The speed change device provided by the invention can greatly reduce impact and abrasion due to zero clearance transmission and relative rolling friction, so that the rolling body of the speed change device is not required to be made of nonferrous metal, the manufacturing cost is reduced, and the rolling body is made of softer material, so that the abrasion to a worm and a worm channel can be effectively avoided, and the service life of the worm is prolonged.

Drawings

FIG. 1 is a schematic structural view of a preferred embodiment of the present invention;

FIG. 2 is a schematic view of a worm gear in a preferred embodiment of the present invention;

FIG. 3 is a structural schematic of the engagement of the worm teeth with the worm path in a preferred embodiment of the present invention;

FIG. 4 is a schematic view of the contact line of a preferred rolling element of the present invention;

FIG. 5 is a schematic view of the contact line of another preferred rolling element of the present invention; and

fig. 6 is a schematic view of the contact line of another preferred roll-on body of the present invention.

List of reference numerals

1: and (3) a box body 2: worm screw

3: the worm wheel 4: volute passage

5: the worm gear 6: rolling body

7: screw hole 61: first rolling element

62: second rolling element 2 a: worm axis

F1: first tangential force F2: second tangential force

F3: first radial force F4 second radial force

4 a: first tooth surface 4 b: second flank

8: contact line 9: line connecting axes of rolling bodies

3 a: worm wheel axis 3 b: worm wheel contour

α: included angle

Detailed Description

The following detailed description is made with reference to the accompanying drawings.

Example 1

The embodiment discloses a speed changing device, and can also be a speed changing device capable of eliminating transmission gaps, and the speed changing device can be realized by the device and/or other alternative parts. The apparatus of the present invention is implemented, for example, by using various components of the apparatus of the present invention. The preferred embodiments of the present invention are described in whole and/or in part in the context of other embodiments, which can supplement the present embodiment, without resulting in conflict or inconsistency.

According to a preferred embodiment, the transmission device capable of eliminating transmission clearance at least comprises a worm 2 and a worm wheel 3 which are arranged in a box body 1 and are opposite to each other in axial line. Preferably, as shown in fig. 1, the casing 1 is provided with at least two openings, one opening being located at one axial end of the worm 2 for connection of servo drive or the like to the worm 2. The worm wheel 3 is likewise provided with an opening at one axial end thereof, which opening is intended for connection with a coupling. Preferably, the axis is not coplanar, which means that the worm wheel axis 3a and the worm wheel axis 2a are not coplanar, and the worm wheel axis 2a and the worm wheel axis 3a are not on the same plane, i.e. they do not intersect and are not parallel. Preferably, the worm axis 2a and the worm wheel axis 3a are orthogonal to each other. Through the arrangement mode, the friction between the worm teeth 5 and the worm channel 4 can be reduced, and the transmission ratio is large.

Preferably, the worm 2 is provided with a plurality of worm ways 4. The plurality of volutes 4 are in the shape of a variable diameter spiral, as shown in fig. 1 and 3. The radius of the worm path 4 at the axial middle position of the worm 2 is smallest. Through this setting mode, optimize the size of worm 5, can increase the number of worm 5 and the 4 engagements of wormwheel, increase the vice bearing capacity of worm gear transmission, even bear heavy load or impact load, also can normal operating. Preferably, the cross-sectional area of both ends of the worm way 4 is the same. Preferably, the worm 2 is generally made of an alloy material, such as 40Cr alloy steel.

Preferably, the worm wheel 3 may be a cylinder. The worm wheel 3 has a worm gear 5 detachably attached thereto. The worm gear 5 may be connected by a toothed spindle integrally formed with the worm wheel 3. For example, the worm gear 5 may be fitted over a toothed mandrel. A roller bearing or a needle bearing can be arranged between the worm gear 5 and the gear center shaft, so that the friction of the worm gear 5 during rotation is reduced. Preferably, the worm gear 5 may be integrally formed with the gear spindle and threadedly mounted on the worm wheel 3. Preferably, the worm wheel 3 is provided with a plurality of worm teeth 5 in circumferentially spaced rows thereof, as shown in fig. 1 and 2. Preferably, the worm 5 comprises at least two rolling bodies 6. The rolling bodies 6 are offset from each other in the axial direction and the circumferential direction of the worm wheel 3, as shown in fig. 1 and 2. Preferably, the rolling bodies 6 of each worm tooth 5 are centrosymmetric to each other. Preferably, the rolling elements 6 forming each worm tooth 5 can be two, three or more and are distributed on both sides of the worm wheel axis 3 b. Preferably, the rolling bodies 6 can rotate about their own axis. The axis of rotation of the rolling bodies 6 is in the radial direction of the worm wheel 3, and the extension line thereof perpendicularly intersects the worm wheel axis 3 a. Preferably, in the case where the worm wheel 3 rotates about the worm wheel axis 3a, the edge of the worm wheel 3 can form a virtual circular motion locus centered on the axis of the worm wheel 3. The worm gear 5 can move along a virtual circular trajectory having the axis of the worm wheel 3 as the center. Preferably, the worm wheel 3 may be made of alloy steel of GCr15, with an elastic modulus E of 206000MPa and a poisson ratio μ of 0.3. Preferably, the rolling bodies 6 may be cylindrical, conical or circular, as shown in fig. 4, 5 and 6, respectively. The rolling bodies 6 may be made of a copper alloy.

Preferably, in the case of a rotation of the worm 2 and/or the worm wheel 3 about its axis, the worm channel 4 at any instant engages with a worm tooth 5 defined by at least two rolling bodies 6, as shown in fig. 1 and 3. The rolling bodies 6 of the worm teeth 5 positioned at both sides of the axis of the worm 2 always make line contact with the tooth surfaces at both sides of the worm path 4. Preferably, line contact means: at the moment when the rolling bodies 6 and the tooth surfaces on both sides of the worm 4 contact each other, at least a part of the contact relationship of the rolling bodies 6 and the worm 4 is a space curve composed of a plurality of continuous contact points adjacent to each other. Preferably, at least a portion of the contacting relationship is between 60% and 100% of the contacting relationship. Preferably, the spatial curve formed by several successive contact points adjacent to each other is the intersection of the rolling surface of the rolling body 6 and the tooth surface of the worm 4, i.e. the contact line 8. As shown in fig. 4, when the rolling element 6 is cylindrical, a tooth surface contact line 8 with the worm gear 4 is a straight line parallel to the axis of the rolling element 6 and located on the rolling surface of the rolling element 6. As shown in fig. 5, when the worm 3 is tapered, its line of contact 8 with the tooth surface of the worm 4 is a straight line on the rolling surface of the rolling element 6. Preferably, as shown in fig. 6, when the rolling elements 6 are circular, the contact line 8 thereof is a space curve from a dome point to a circular edge. Through this mode of setting, at driven in-process, the both sides flank of tooth of worm way 4 all have at least one rolling element 6 to support and lean on to can there be not the transmission of flank clearance, eliminate the return error, and can avoid the impact that the flank clearance brought in the twinkling of an eye in worm wheel 3 direction of rotation switching, reduce the wearing and tearing between the teeth. Because the two rolling bodies 6 are always in line contact with the tooth surfaces on the two sides of the worm channel 4, relative sliding friction between the tooth surfaces is converted into relative rolling friction, so that not only can the abrasion between the teeth be further reduced, but also the problem of tooth side clearance caused by the abrasion of the tooth surfaces can be reduced, the transmission stability and the transmission efficiency are improved, and the precision life is prolonged.

Preferably, the axes connecting lines between two rolling bodies 6 respectively rotate in a manner of intersecting the axes of the worm 2 in a non-perpendicular manner. Preferably, the plurality of rolling bodies 6 are distributed on both sides of the worm axis 2a, and the plurality of rolling bodies 6 are also in contact with the left and right tooth faces of the worm wheel 4, respectively. Preferably, the axis connecting line between the rolling bodies 6 is as shown in fig. 3, and the rolling body axis connecting line 9 intersects the worm axis 2a in a non-perpendicular manner, so that the arrangement can ensure that the contact with the tooth surfaces on both sides of the worm 4 is kept at any time when the worm 5 is engaged with the worm 4, and the occurrence of the inter-tooth gap is avoided.

Preferably, the worm wheel 3 is detachably connected by an upper disk and a lower disk in the axial direction of the worm wheel 3. Preferably, a plurality of rolling bodies 6 are arranged at intervals in the circumferential direction of the upper disc and the lower disc. Preferably, the upper and lower disks are connected to each other with a shift so that two axially adjacent rollers 6 of the worm wheel 3 are shifted from each other. Two rolling bodies 6 on different disks form the worm tooth 5 in line contact with the tooth flanks on both sides of the worm channel 4, and the axes of the two rolling bodies 6 form an angle α with each other, forming the worm wheel 3 shown in fig. 1 and 2. Preferably, the upper and lower discs are provided with a plurality of oval screw holes 7. The oval screw holes 7 facilitate the staggered installation of the rolling bodies 6. Preferably, the upper and lower disks are mounted by inserting bolts into the screw holes 7. Through the arrangement mode, the included angle alpha between the two rolling bodies 6 of the worm gear 5 can be adjusted by utilizing the friction between the bolts to achieve the function of automatically eliminating the clearance, so that the function of automatically eliminating the tooth side clearance is realized while the zero clearance transmission is realized. And the clearance between the two rolling bodies 6 in the worm gear 5 and the tooth surface of the worm channel 4 is adjusted through the friction between the bolts, the structure is simple and compact, and the kinematic pair between the two disks is a low pair, so the processing and the manufacturing are convenient, and the cost is low.

Preferably, an elastic body can be arranged between the upper disc and the lower disc, for example, a rotary spring is arranged at the joint of the axes of the two discs, and the included angle α is forced to be increased by the elastic action of the spring, so that at least two rolling bodies 6 of the worm gear 5 are always attached to the tooth surfaces on two sides of the worm channel 4, and bidirectional zero-gap transmission is realized, and the transmission device is always ensured to be in zero-gap transmission. In the transmission process of the speed changing device, instant rigid impact can occur to cause the gap between teeth to appear or impact the worm gear 5 to cause the worm gear 5 to be abraded, but the elastic body adopted by the invention forces the included angle alpha of the two rolling bodies 6 to be enlarged, and at the impact instant, the impact born by the rolling bodies 6 is absorbed by the elastic body and slowly released, thereby reducing the damage of the impact on the rolling bodies and prolonging the precision life.

Through the arrangement mode, the speed changing device provided by the invention can greatly reduce impact and abrasion due to zero clearance transmission and relative rolling friction, so that the rolling body 6 of the speed changing device is not required to be made of nonferrous metal, the manufacturing cost is reduced, and the rolling body is made of softer materials, so that the abrasion caused to the worm channel 4 of the worm 2 can be effectively avoided, and the service life of the worm 2 is prolonged.

According to a preferred embodiment, the worm 5 comprises at least a first rolling element 61 and a second rolling element 62 arranged axially spaced apart along the worm wheel 3, as shown in fig. 3. In the case where the worm wheel 3 rotates in the first direction or the second direction about the axis thereof, at least one worm tooth 5 engages with the worm gear 4 such that the first rolling body 61 and the second rolling body 62 are in line contact with both side tooth surfaces of the worm gear 4, respectively. Preferably, the first direction may be a clockwise direction and the second direction may be a counterclockwise direction. Preferably, the first rolling element 61 is in contact with the first tooth surface 4a and the second rolling element 62 is in contact with the second tooth surface 4 b. Preferably, the length of the axis connecting line of the first rolling element 61 and the second rolling element 62 is kept constant under the condition that no loss occurs between the teeth of the worm 4 and the precision is kept constant. With this arrangement, in the transmission frequent forward-reverse transmission, the first rolling elements 61 are always kept in contact with the first tooth surface 4a, and the second rolling elements 62 are always kept in contact with the second tooth surface 4 b. The first rolling elements 61 and the second rolling elements 62 can realize the backlash-free transmission between the worm wheel 3 and the worm 2 by forming relative rolling friction.

According to a preferred embodiment, in the case where the worm 2 rotates about its axis and at least two of the worm teeth 5 engage with the worm channel 4, the first tangential force F1 and the first radial force F3 are applied to the first rolling body 61 by the first rolling body 61 defining the worm teeth 5 contacting with the first tooth face 4a of the worm channel 4, as shown in fig. 3. Preferably, a second tangential force F2 in the same direction as the first tangential force F1 and a second radial force F4 opposite to the first radial force F3 are applied to the second rolling elements 62 by the second rolling elements 62 defining the worm teeth 5 contacting the second tooth face 4b of the worm gear 4, as shown in fig. 3. The first tangential force F1 causes the first rolling element 61 to rotate about its axis by rolling friction between the first rolling element 61 and the first tooth surface 4 a. The second tangential force F2 causes the second rolling element 62 to rotate about its axis by rolling friction between the second rolling element 62 and the second tooth surface 4 b. The worm wheel 3 rotates about its axis by a first radial force F3 transmitted through the first rolling elements 61 and a second radial force F4 transmitted through the second rolling elements 62. Preferably, in the case where the worm 2 rotates around its axis and the first radial force F3 is greater than the second radial force F4, the worm tooth 5 drives the worm wheel 3 to rotate around the axis of the worm wheel 3 in the direction of the first radial force F3 by the first radial force F3 and the second radial force F4 which are opposite in direction. The first rolling elements 61 are rotated around their axes at an angular velocity greater than the rotation of the second rolling elements 62 by a first tangential force F1 greater than a second tangential force F2. Preferably, in the case where the worm 2 rotates around its axis and the first radial force F3 is smaller than the second radial force F4, the worm tooth 5 drives the worm wheel 3 to rotate around the axis of the worm wheel 3 in the direction of the second radial force F4 by the first radial force F3 and the second radial force F4 which are opposite in direction. The first rolling elements 61 are rotated about their axes at an angular velocity smaller than the rotation of the second rolling elements 62 by a first tangential force F1 smaller than the second tangential force F2. Preferably, the rolling body 6 on the tooth surface on the heavy-load side of the worm channel 4 rotates at a larger angular speed, so that the impact load of variable speed in the transmission process can be partially eliminated, and the smoothness in the transmission process is improved.

Example 2

This embodiment discloses a transmission that may be implemented by the device of the present invention and/or other alternative components. The apparatus of the present invention is implemented, for example, by using various components of the apparatus of the present invention. The preferred embodiments of the present invention are described in whole and/or in part in the context of other embodiments, which can supplement the present embodiment, without resulting in conflict or inconsistency.

In a transmission, preferably, as shown in fig. 1, a housing 1 is provided with at least two openings, one opening being located at an axial end of a worm 1 for connection of servo-drive and the like to the worm 1. The worm wheel 3 is likewise provided with an opening at one axial end thereof, which opening is intended for connection with a coupling. Preferably, the axis is not coplanar, which means that the worm wheel axis 3a and the worm wheel axis 2a are not coplanar, and the worm wheel axis 2a and the worm wheel axis 3a are not on the same plane, i.e. they do not intersect and are not parallel. Preferably, the worm axis 2a and the worm wheel axis 3a are orthogonal to each other. Through the arrangement mode, the friction between the worm teeth 5 and the worm channel 4 can be reduced, and the transmission ratio is large.

Preferably, the worm channel 4 at any instant is engaged with a worm tooth 5 defined by at least two rolling bodies 6 in case the worm 2 and/or the worm wheel 3 rotates around its axis. As shown in fig. 1 and 3. Preferably, the rolling elements 6 of the worm teeth 5, which are in at least partial line contact with each other with the flank surfaces on both sides of the worm 4, respectively, rotate around their respective axes in a manner that the directions of rotation are always opposite to each other. Preferably, the local line contact means: at the moment when the rolling bodies 6 and the tooth surfaces on both sides of the worm 4 contact each other, at least a part of the contact relationship of the rolling bodies 6 and the worm 4 is a space curve composed of a plurality of continuous contact points adjacent to each other. Preferably, at least a portion of the contacting relationship is between 60% and 100% of the contacting relationship. Preferably, the spatial curve formed by several successive contact points adjacent to each other is the intersection of the rolling surface of the rolling body 6 and the tooth surface of the worm 4, i.e. the contact line 8. As shown in fig. 4, when the rolling element 6 is cylindrical, a tooth surface contact line 8 with the worm gear 4 is a straight line parallel to the axis of the rolling element 6 and located on the rolling surface of the rolling element 6. As shown in fig. 5, when the worm 3 is tapered, its line of contact 8 with the tooth surface of the worm 4 is a straight line on the rolling surface of the rolling element 6. As shown in fig. 6, when the rolling element 6 has a circular shape, its contact line 8 is a space curve from a dome point to a circular edge. Preferably, the rolling bodies 6 of the worm teeth 5 in line contact with the tooth surfaces on both sides of the worm path 4 respectively rotate around their respective axes in such a manner that the directions of rotation are always opposite to each other. That is, it is ensured that the teeth on both sides generate tangential forces in the same direction to the rolling elements 6 at any time, and the rolling elements 6 are in contact with the tooth surfaces on both sides of the worm path 4 in a state of at least relative rolling. Through this mode of setting, at driven in-process, the both sides flank of tooth of worm way 4 all have at least one rolling element 6 to support and lean on to can there be not the transmission of flank clearance, eliminate the return error, and can avoid the impact that the flank clearance brought in the twinkling of an eye in worm wheel 3 direction of rotation switching, reduce the wearing and tearing between the teeth. Because the two rolling bodies 6 are always in line contact with the tooth surfaces on the two sides of the worm channel 4, relative sliding friction between the tooth surfaces is converted into relative rolling friction, so that not only can the abrasion between the teeth be further reduced, but also the problem of tooth side clearance caused by the abrasion of the tooth surfaces can be reduced, the transmission stability and the transmission efficiency are improved, and the precision life is prolonged.

Preferably, the worm wheel 3 is detachably connected by an upper disk and a lower disk in the axial direction of the worm wheel 3. Preferably, a plurality of rolling bodies 6 are arranged at intervals in the circumferential direction of the upper disc and the lower disc. Preferably, the upper and lower disks are connected to each other in a staggered manner so that two axially adjacent rollers 6 of the worm wheel 3 are offset from each other and form an angle α, forming the worm wheel 3 as shown in fig. 1 and 2. Preferably, the upper and lower discs are provided with a plurality of oval screw holes 7. The oval screw holes 7 facilitate the staggered installation of the rolling bodies 6. Preferably, the upper and lower disks are mounted by inserting bolts into the screw holes 7. Through the arrangement mode, the included angle alpha between the two rolling bodies 6 of the worm gear 5 can be adjusted by utilizing the friction between the bolts to achieve the function of automatically eliminating the clearance, so that the function of automatically eliminating the tooth side clearance is realized while the zero clearance transmission is realized. And the clearance between the two rolling bodies 6 in the worm gear 5 and the tooth surface of the worm channel 4 is adjusted through the friction between the bolts, the structure is simple and compact, and the kinematic pair between the two disks is a low pair, so the processing and the manufacturing are convenient, and the cost is low.

Example 3

This embodiment is a gap elimination method corresponding to

embodiments

1, 2 and 3, and repeated description is omitted.

A clearance elimination method comprises the step of eliminating the clearance between the worm teeth 5 and the worm channel 4 by the speed changing device of one of the preferred embodiments. Preferably, the transmission comprises at least a worm 2 and a worm wheel 3, arranged inside the casing 1, with axes that are not coplanar with each other. Preferably, as shown in fig. 1, the casing 1 is provided with at least two openings, one opening being located at one axial end of the worm 1 for connection of servo drive and the like to the worm 1. The worm wheel 3 is likewise provided with an opening at one axial end thereof, which opening is intended for connection with a coupling. Preferably, the axis is not coplanar, which means that the worm wheel axis 3a and the worm wheel axis 2a are not coplanar, and the worm wheel axis 2a and the worm wheel axis 3a are not on the same plane, i.e. they do not intersect and are not parallel. Preferably, the worm axis 2a and the worm wheel axis 3a are orthogonal to each other. Through the arrangement mode, the friction between the worm teeth 5 and the worm channel 4 can be reduced, and the transmission ratio is large.

Preferably, the worm wheel 3 is detachably connected by a left half worm wheel and a right half worm wheel in the axial direction of the worm wheel 3. Preferably, a plurality of rolling bodies 6 are arranged at intervals in the circumferential direction of the left half worm wheel and the right half worm wheel. Preferably, the left half worm wheel and the right half worm wheel are connected in a staggered manner so that two axially adjacent rollers 6 of the worm wheel 3 are staggered with respect to each other, forming the worm wheel 3 shown in fig. 1 and 2. Preferably, the left and right worm wheel halves are provided with a plurality of oval screw holes 7. The oval screw holes 7 facilitate the staggered installation of the rolling bodies 6. Preferably, the left and right half worm wheels are installed by inserting bolts into the screw holes 7. Through the arrangement mode, the position between the two rolling bodies 6 of the worm gear 5 can be adjusted by utilizing the friction between the bolts to achieve the function of automatically eliminating the clearance, so that the function of automatically eliminating the tooth side clearance is realized while the zero clearance transmission is realized. And the clearance between the two rolling bodies 6 in the worm gear 5 and the tooth surface of the worm channel 4 is adjusted through the friction between the bolts, the structure is simple and compact, and the kinematic pair between the two half worm gears is a low pair, so the processing and the manufacturing are convenient, and the cost is low.

It should be noted that the above-mentioned embodiments are exemplary, and that those skilled in the art, having benefit of the present disclosure, may devise various arrangements that are within the scope of the present disclosure and that fall within the scope of the invention. It should be understood by those skilled in the art that the present specification and figures are illustrative only and are not limiting upon the claims. The scope of the invention is defined by the claims and their equivalents.

Claims

1. A speed change device capable of eliminating transmission clearance at least comprises a worm (2) and a worm wheel (3) which are arranged in a box body (1) and have different axial surfaces, wherein the worm wheel (3) is provided with detachable worm teeth (5) which are arranged at intervals along the circumferential direction and can be mutually jointed with a worm channel (4) of the worm (2),

it is characterized in that the worm wheel (3) comprises at least two disks which are attached to each other in the axial direction, the radial outer sides of the at least two disks are respectively provided with rolling bodies (6) which are arranged at intervals along the circumferential direction,

in the case of a rotation of the worm (2) and/or worm wheel (3) about its axis, the worm channel (4) at any one instant engages with the worm teeth (5) defined by rolling bodies (6) of at least two disks which are axially adjacent to one another and have an angle α, the rolling bodies (6) of the worm teeth (5) on both sides of the axis of the worm (2) always being in line contact with both side flanks of the worm channel (4) in such a way that the angle α can be adjusted and the rolling bodies (6) each rotate in such a way that the axis connecting lines between two and two intersect the axis of the worm (2) non-perpendicularly, wherein,

the included angle alpha is formed between the axes of two circumferentially adjacent rolling bodies (6) on different discs;

the worm teeth (5) at least comprise a first rolling body (61) and a second rolling body (62) which are arranged at intervals along the axial direction of the worm wheel (3),

under the condition that the worm wheel (3) rotates around the axis of the worm wheel in a first direction or a second direction, at least one worm tooth (5) is engaged with the worm channel (4) so that the first rolling body (61) and the second rolling body (62) are respectively in linear contact with two side tooth surfaces of the worm channel (4), and the axial connecting line of the first rolling body (61) and the second rolling body (62) keeps unchanged in length so that the worm tooth (5) and the worm channel (4) form relative rolling friction to realize gapless transmission of the worm wheel (3) and the worm (2);

at the moment that the tooth surfaces on the two sides of the rolling body (6) and the worm way (4) are contacted with each other, at least one part of the contact relation between the rolling body (6) and the worm way (4) is a space curve formed by a plurality of continuous contact points which are adjacent to each other;

the upper disc and the lower disc are provided with a plurality of oval screw holes (7), the upper disc and the lower disc are installed by inserting bolts into the screw holes (7), and therefore the included angle alpha between two rolling bodies (6) of the worm gear (5) is adjusted by utilizing the friction between the bolts to achieve the function of automatically eliminating the gap; -applying a first tangential force and a first radial force to a first rolling body (61) defining the worm tooth (5) by contacting the first rolling body (61) with a first flank of the worm gear (4) and-applying a second tangential force in the same direction as the first tangential force and a second radial force opposite to the first radial force to a second rolling body (62) defining the worm tooth (5) by contacting the second flank of the worm gear (4) with the worm gear (2) rotating about its own axis and with at least two worm teeth (5) engaging the worm gear (4), wherein,

the first tangential force drives the first rolling body (61) to rotate around the axis of the first rolling body (61) through rolling friction between the first rolling body (61) and the first tooth surface;

the second tangential force drives the second rolling body (62) to rotate around the axis of the second rolling body (62) through rolling friction between the second rolling body (62) and the second tooth surface;

the worm wheel (3) is rotated about its axis by the first radial force transmitted by the first rolling elements (61) and by the second radial force transmitted by the second rolling elements (62).

2. A transmission according to claim 1, characterized in that in case the worm (2) rotates around its axis and the first radial force is larger than the second radial force, the worm gear (5) drives the worm wheel (3) to rotate around the axis of the worm wheel (3) in the direction of the first radial force by the first radial force and the second radial force in opposite directions, and

the first rolling element (61) rotates around its axis at an angular velocity greater than the rotation of the second rolling element (62) by a first tangential force greater than the second tangential force.

3. A transmission according to claim 2, characterized in that in case the worm (2) rotates around its axis and the first radial force is smaller than the second radial force, the worm gear (5) drives the worm wheel (3) to rotate around the axis of the worm wheel (3) in the direction of the second radial force by the first and second radial forces in opposite directions, and

the first rolling element (61) rotates around its axis at a speed smaller than the angular velocity of the second rolling element (62) due to a first tangential force smaller than the second tangential force.

4. A speed change device at least comprises a worm (2) and a worm wheel (3) which are arranged in a box body (1) and have different axial surfaces, wherein the worm wheel (3) is provided with detachable worm teeth (5) which are arranged at intervals along the circumferential direction and can be mutually jointed with a worm channel (4) of the worm (2),

in the case of a rotation of the worm (2) and/or worm wheel (3) about their axes, the worm channel (4) at any instant engages the worm teeth (5) defined by at least two rolling bodies (6), the worm teeth (5) respectively rotating about their respective axes in such a way that the rolling bodies (6), whose flank surfaces on both sides of the worm channel (4) are at least partially in line contact with each other, always rotate in opposite directions to each other;

the worm wheel (3) is composed of an upper disc and a lower disc, the upper disc and the lower disc are provided with a plurality of oval screw holes (7), the upper disc and the lower disc are installed by inserting bolts into the screw holes (7), and therefore the included angle alpha between two rolling bodies (6) of the worm gear (5) is adjusted by utilizing the friction between the bolts to achieve the function of automatically eliminating the gap;

-applying a first tangential force and a first radial force to a first rolling body (61) defining the worm tooth (5) by contacting the first rolling body (61) with a first flank of the worm gear (4) and-applying a second tangential force in the same direction as the first tangential force and a second radial force opposite to the first radial force to a second rolling body (62) defining the worm tooth (5) by contacting the second flank of the worm gear (4) with the worm gear (2) rotating about its own axis and with at least two worm teeth (5) engaging the worm gear (4), wherein,

5. Transmission according to claim 4, characterized in that in case the worm (2) rotates around its axis and the first radial force is larger than the second radial force, the worm teeth (5) drive the worm wheel (3) to rotate around the axis of the worm wheel (3) in the direction of the first radial force by the first and second radial forces in opposite directions, and in that

6. A method of clearance elimination, characterized in that the method comprises eliminating the clearance between the worm teeth (5) and the worm path (4) using the transmission of any one of claims 1 to 5.