CN103883679B - Plane-enveloping toroidal worm drives capable of maintaining accuracy after worm gear teeth wear - Google Patents

Abstract

The invention relates to a plane enveloping ring surface worm transmission capable of keeping precision after worm wheel teeth are worn, wherein the tooth part of a worm wheel is formed by gear teeth with consistent tooth shapes along the tooth length direction of the gear teeth, which are formed by feeding and processing a cutter along the axis direction of the worm wheel or along the linear direction forming a certain angle with the axis of the worm wheel, the tooth top of the worm wheel is a cylindrical surface, the tooth surfaces at two sides of the worm wheel teeth are planes, and the inclination angles of the tooth surfaces at two sides of the worm wheel teeth relative to the axis of the worm wheel are equal; the worm is meshed with the worm wheel and can move along the axis of the worm wheel, and when the worm moves to different positions along the axis of the worm wheel, the tooth surfaces on the two sides of the worm respectively use the corresponding side tooth surfaces of the teeth of the worm wheel as mother surfaces and form an envelope surface by generating motion according to the meshing relationship between the worm wheel and the worm. According to the distribution characteristics of the contact lines, after the gear teeth of the worm wheel are worn, the worm is moved to the area where the gear teeth of the worm wheel are not in contact wear with the worm, and the service life is prolonged under the condition that the contact performance of the worm wheel is not influenced.

Description

Plane-enveloping toroidal worm drives capable of maintaining accuracy after worm gear teeth wear

technical field

The invention relates to a worm drive, in particular to a planar enveloping toroidal worm drive capable of maintaining precision after the gear teeth of the worm gear are worn.

Background technique

The worm drive belongs to the cross-shaft drive, which has the characteristics of compact structure, stable transmission, low noise and small motion error. Therefore, it is widely used in mechanical equipment as a reduction device and precision transmission device. With the development of precision machinery, the requirements for precision indexing and precision reducers are getting higher and higher, and the demand is also increasing. Compared with ordinary worm drives, planar enveloping toroidal worm drives have the following advantages in addition to all the advantages of ordinary worm drives:

1) The number of teeth that the ordinary worm transmission contacts at the same time is 1-2, while the number of teeth of the worm surrounded by the worm gear of the plane enveloping toroidal worm transmission is one-tenth of the number of teeth of the worm gear, and the number of teeth that can be contacted at the same time can reach more than 4 to 10. Therefore, the bearing capacity is large, and under the same load conditions, the size can be significantly reduced and the material consumption can be reduced. At the same time, since the planar enveloping toroidal worm drive is multi-tooth contact at the same time, it can also produce an error averaging effect and improve the accuracy.

2) The worm of ordinary worm drive can be ground, but the grinding of worm gear is difficult, while both the worm gear and worm of planar enveloping toroidal worm drive can be ground, so it is easy to manufacture precisely and can manufacture higher precision worm drive.

3) Ordinary worm drive has high friction and low efficiency, while planar enveloping toroidal worm drive is easy to establish dynamic pressure oil film, has small friction coefficient and high transmission efficiency. Generally, it can increase transmission efficiency by 10-15% and save energy. At the same time, because the friction coefficient of the planar enveloping toroidal worm drive is small, the dead zone of its fretting is small, and the fretting that can be realized is smaller, and the realized precision is also higher.

Worm drives used in precision indexing mechanisms and precision reducers require high precision and strict backlash. It can be seen from the above that the planar enveloping toroidal worm drive is much superior to the ordinary worm drive in terms of accuracy and life, and is more suitable for precision indexing mechanisms and precision reducers. However, the currently known planar enveloping toroidal worm drive generally cannot maintain the initial accuracy and backlash through adjustment after wear, so that the precision indexing mechanism and the precision reducer cannot continue to be used after wear.

Chinese patent 99117383.X proposes a plane-enveloping toroidal worm drive with adjustable backlash. Compared with ordinary double-lead cylindrical worm drive, it has better performance. This kind of backlash adjustable planar enveloping toroidal worm transmission is composed of a worm gear and a toroidal worm, in which the tooth surfaces on both sides of the worm gear teeth are planes, and their inclination angles relative to the axis of the worm gear are not equal (β ₁ ≠ β ₂ ), so that the worm gear teeth are wedge-shaped along its axial direction, and a suitable backlash can be obtained by moving the worm along the axial direction of the worm gear. This kind of backlash adjustable planar enveloping toroidal worm drive can adjust the backlash to a suitable value during initial installation, but after wear and tear, the following problems will occur:

1) Since the worm wheel is easy to wear, but the worm hardly wears, the unworn worm cannot move to the wedge-shaped area of the unworn worm wheel, which is smaller than it, so the backlash cannot be adjusted after the worm wheel is worn.

2) Due to the influence of the load, the wear of the worm gear tooth surface cannot be guaranteed to be uniform. Therefore, after wear, the backlash-adjustable planar enveloping toroidal worm drive will lose its original accuracy.

Patent No. 99117383.X only proposes a planar enveloping toroidal worm drive with adjustable backlash between adjacent teeth, but does not propose how to maintain the original precision of the planar enveloping toroidal worm drive.

It can be seen that the above-mentioned existing planar enveloping toroidal worm drive clearly still has inconvenience and defects in product structure, method and use, and needs to be further improved urgently. In view of this, based on the rich practical experience and professional knowledge engaged in the design and manufacture of such products for many years, and with the application of academic theory, the designer actively researches and innovates, in order to create a new plane that can maintain precision after the teeth of the worm gear are worn out. The enveloping toroidal worm transmission can improve the general existing planar enveloping toroidal worm transmission, making it more practical. Through continuous research, design, and after repeated trial samples and improvements, the present invention with practical value is finally created.

Contents of the invention

The purpose of the present invention is to overcome the defects of the existing plane enveloping toroidal worm transmission, and provide a new plane enveloping toroidal worm transmission that can maintain accuracy after the gear teeth of the worm gear are worn. The technical problem to be solved is After the teeth of the worm gear are worn, by moving the worm to the area where the teeth of the worm gear are not in contact with the worm, it is possible to extend the efficiency of the plane enveloping toroidal worm drive while maintaining the meshing accuracy and backlash of the worm gear and the worm. Long service life, very suitable for practical use.

The purpose of the present invention and the solution to its technical problems are achieved by adopting the following technical solutions. According to the present invention, a planar enveloping toroidal worm transmission that can maintain precision after the teeth of the worm gear wears out includes a worm wheel and a worm, and the teeth of the worm wheel are formed by a tool or a grinding wheel along the axial direction of the worm wheel or Feed processing along a straight line at a certain angle to the axis of the worm gear and consist of teeth that have the same tooth shape along the tooth length direction of the worm gear teeth, wherein the tooth tip of the worm gear is a cylindrical surface, The tooth surfaces on both sides of the worm gear teeth are planes, and the inclination angles of the tooth surfaces on both sides of the worm gear teeth relative to the axis of the worm wheel are equal; the worm meshes with the worm wheel and can move along the When the worm moves along the axis of the worm wheel to different positions to mesh with the worm wheel, the tooth surfaces on both sides of the worm take the corresponding side tooth surfaces of the worm gear teeth as the parent surfaces , the envelope surface formed by generating motion according to the meshing relationship between the worm wheel and the worm.

The purpose of the present invention and the solution to its technical problems can also be further realized by adopting the following technical measures.

The aforementioned planar enveloping toroidal worm drive that can maintain precision after the teeth of the worm gear wears out, wherein the worm determines the initial position and position of the worm according to the distribution of the contact line between the worm and the worm gear. The direction and distance that the worm moves along the axis of the worm wheel after the worm wheel wears out to move along the axis of the worm wheel.

The aforementioned planar enveloping toroidal worm transmission capable of maintaining precision after the teeth of the worm gear wears out, wherein when the tool or the grinding wheel is fed along a straight line at a certain angle to the axis of the worm wheel to process the gear teeth, the The angle formed by the feed direction of the tool or the grinding wheel and the axis of the worm wheel is greater than 0 degrees and less than 90 degrees.

Compared with the prior art, the present invention has obvious advantages and beneficial effects. By virtue of the above-mentioned technical scheme, the plane enveloping toroidal worm drive of the present invention that can maintain precision after the worm gear teeth are worn has at least the following advantages and beneficial effects: According to the distribution characteristics of the contact line, the present invention adopts the method of moving the worm until the worm gear teeth are not in contact with the The area of the worm contact wear prolongs the service life of the planar enveloping toroidal worm drive without affecting its contact performance.

The above description is only an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention, it can be implemented according to the contents of the description, and in order to make the above and other purposes, features and advantages of the present invention more obvious and understandable , the following preferred embodiments are specifically cited, and in conjunction with the accompanying drawings, the detailed description is as follows.

Description of drawings

1A to 1D are distribution diagrams of the contact line between the worm and the worm wheel when the tooth direction of the worm gear is at different angles to the axis of the worm wheel.

Fig. 2 is a distribution diagram of the contact line between the worm and the worm wheel before and after the worm moves along the axis of the worm wheel according to the present invention.

3A to 3B are schematic views of the direction of tool feed when machining the worm wheel of the present invention.

Fig. 4 is a schematic diagram of the inclination angles of the tooth surfaces on both sides of the worm gear teeth relative to the axis of the worm gear according to the present invention.

Figure 5 is a schematic diagram of the position of the worm screw of the present invention meshed with the worm wheel before and after wear.

detailed description

In order to further explain the technical means and effects adopted by the present invention to achieve the intended purpose of the invention, the planar enveloping toroidal worm proposed according to the present invention that can maintain accuracy after the worm gear teeth are worn is described below in conjunction with the accompanying drawings and preferred embodiments. Transmission its specific implementation, structure, steps, features and effects, as follows in detail.

The aforementioned and other technical contents, features and effects of the present invention will be clearly presented in the following detailed description of preferred embodiments with reference to the drawings. Through the description of specific embodiments, it should be possible to obtain a deeper and more specific understanding of the technical means and effects of the present invention to achieve the intended purpose, but the attached drawings are only for reference and description, and are not used to explain the present invention. be restricted.

The known planar enveloping toroidal worm drive is divided into two types: straight teeth and helical teeth according to whether the tooth direction of the worm gear is parallel to the axis of the worm gear, as shown in Figures 1A to 1D, and Figures 1A to 1D are worm gears The distribution diagram of the contact line between the worm and the worm wheel when the tooth direction is at different angles to the axis of the worm wheel. It can be seen from the distribution of the contact line in the figure that whether it is a straight tooth (β=0°) or a helical tooth (β≠0°), half of the tooth surface of the worm gear has no contact line (called the non-contact area) , that is, half of the tooth surface of the worm gear is not in contact with and meshed with the worm, and this half of the tooth surface does not have any wear.

Please refer to FIG. 2 , which is a distribution diagram of the contact line between the worm and the worm wheel before and after the worm moves along the axis of the worm wheel according to the present invention. The planar enveloping toroidal worm transmission that can maintain precision after the worm gear teeth wear out in the present invention is based on the distribution diagram of the contact line between the worm and the worm gear, so that the worm can move correspondingly along the axial direction of the worm wheel, so that the moved worm The contact line meshed with the worm gear is distributed in the non-contact area of the tooth surface of the worm gear to maintain the initial precision and backlash of the mesh between the worm and the worm gear by moving the worm after the teeth of the worm gear wear.

Please refer to FIG. 3A to FIG. 3B and FIG. 4 . FIG. 3A to FIG. 3B are schematic views of the direction of tool feeding when machining the worm wheel of the present invention. Fig. 4 is a schematic diagram of the inclination angles of the tooth surfaces on both sides of the worm gear teeth relative to the axis of the worm gear according to the present invention. The planar enveloping toroidal worm transmission that can maintain precision after the teeth of the worm gear wear out in the present invention includes a worm gear 1 and a worm 2 . The tooth portion of the worm wheel 1 is processed by feeding the tool or grinding wheel along the axis direction of the worm wheel 1 (β=0°) or along a straight line at a certain angle (β≠0°) with the axis of the worm wheel 1 The tooth shape along the tooth length direction of the worm gear 1 is composed of teeth with the same tooth shape, so that when the worm gear 1 wears out, it can be ensured that when the worm 2 moves to a new position, their meshing is the same as that at the initial position The same, thus maintaining the accuracy and backlash before wear. When the tool or grinding wheel is fed along a straight line at a certain angle to the axis of the worm wheel 1 to process the gear teeth, the angle β formed between the feeding direction of the tool or the grinding wheel and the axis of the worm wheel is greater than 0 degrees and less than 90 degrees. The addendum of the worm gear 1 of the present invention is a cylindrical surface, which is different from the form of the addendum of the known planar enveloping toroidal worm gear. The tooth tip of the known planar enveloping toroidal worm transmission worm gear has a throat of the inner ring surface. During processing, a tool or a grinding wheel is used to feed radially, and the bottom of the tooth is arc-shaped. This structure determines that the worm cannot move along the Axial movement of the worm gear. The tooth top of the worm wheel 1 of the present invention adopts the same cylindrical surface as the tooth top of an ordinary gear, and the cutting tool 3 or the grinding wheel are fed along the axial direction of the worm wheel 1 during processing to process straight teeth (as shown in Figure 3A), or It is to feed along a straight line at a certain angle to the axis of the worm wheel 1, and process the helical teeth (as shown in Figure 3B), so that the worm 2 can move freely along the axis of the worm wheel 1. The tooth surfaces on both sides of the teeth of the worm wheel 1 of the present invention are planes, and the inclination angles of the tooth surfaces on both sides of the teeth of the worm wheel 1 relative to the axis of the worm wheel 1 are equal, as shown in Figure 4, wherein the two inclination angles β ₁ = β ₂ In this way, the cylindrical surfaces of different diameters from the top to the root of the tooth are parallel to the intersection line of the tooth surfaces on both sides of the tooth, that is, the tooth profiles of the teeth cut by different planes perpendicular to the axis of the worm wheel 1 are straight teeth , consistent tooth shape.

Please refer to FIG. 5 , which is a schematic diagram of the meshing position of the worm and the worm wheel of the present invention before and after wear. The worm 2 of the present invention meshes with the worm wheel 1 and can move along the axis of the worm wheel 1. When the worm 2 moves along the axis of the worm wheel 1 to different positions and meshes with the worm wheel 1, the tooth surfaces on both sides of the worm 2 are respectively formed by the worm wheel. The corresponding side tooth surface of the 1 gear tooth is used as the parent surface, and the envelope surface formed by generating motion according to the meshing relationship between the worm wheel 1 and the worm 2. That is, when machining the tooth surface of the worm 2, a plane with the same inclination (β ₁ =β ₂ ) as that of the worm gear 1 is used. As shown in FIG. 5 , a is the initial position of the worm 2 when it is initially installed, and b is the position of the worm 2 after it moves along the axis of the worm wheel 1 after wear. The worm 2 of the present invention contacts and meshes with the worm wheel 1 at the initial position. After a period of time, the teeth of the worm wheel 1 are worn, and the worm 2 is moved along the axial direction of the worm wheel 1 to the area of the worm wheel 1 that is not in contact with the worm 2 and worn. The contact meshing can prolong the service life of the plane enveloping toroidal worm drive under the condition of maintaining the initial precision and backlash. Wherein the worm 2 of the present invention determines the initial position of the worm 2 and the direction and distance that the worm 2 moves along the axis of the worm 1 after the worm 1 wears out according to the distribution of the contact line between the worm 2 and the worm gear 1 .

According to specific conditions of use, the present invention can appropriately change the angle β to change the distribution of the antennae or appropriately thicken the worm wheel 1, so that the worm 2 can move to the non-contact area on the worm wheel 1 for many times and maintain its contact performance continuously. Therefore, the service life of the present invention is at least twice that of a planar enveloping toroidal worm drive which cannot maintain the original accuracy and backlash.

The above description is only a preferred embodiment of the present invention, and does not limit the present invention in any form. Although the present invention has been disclosed as above with preferred embodiments, it is not intended to limit the present invention. Anyone familiar with this field Those skilled in the art, without departing from the scope of the technical solution of the present invention, may use the method and technical content disclosed above to make some changes or modify equivalent embodiments with equivalent changes, but if they do not depart from the content of the technical solution of the present invention, Any simple modifications, equivalent changes and modifications made to the above embodiments according to the technical essence of the present invention still fall within the scope of the technical solutions of the present invention.

Claims (2)

1. the Property of Plane-enveloped Worm Transmission of precision after a worm gear teeth abrasion, can be kept, including worm gear and worm screw, it is characterized in that: the teeth portion of described worm gear or is made up of along the axis direction of described worm gear along the gear teeth consistent along the tooth length direction profile of tooth of described worm gear teeth processed with the rectilinear direction feeding that the axis of described worm gear acutangulates cutter or emery wheel, the tooth top of wherein said worm gear is the face of cylinder, two lateral tooth flanks of described worm gear teeth are plane, and two lateral tooth flanks of described worm gear teeth are equal relative to the inclination angle of the axis of described worm gear；Described worm screw engages with described worm gear, and can move along the axis of described worm gear, when described worm screw is moved along the axis of described worm gear and to engage with described worm gear to different positions, the flank of tooth of described worm screw both sides is all respectively using the corresponding lateral tooth flank of described worm gear teeth as generatrix, makes, by the meshing relation of described worm gear Yu described worm screw, the enveloping surface that generating motion is formed.

2. the Property of Plane-enveloped Worm Transmission of precision after worm gear teeth according to claim 1 abrasion, can be kept, it is characterized in that wherein said worm screw is the situation of the contact wire distribution engaged with described worm gear according to described worm screw, it is determined that the initial position of described worm screw and after described worm gear weares and teares described worm screw move along the direction that the axis of described worm gear moves and distance along the axis of described worm gear.