CN116951079A - Bevel gear with double-sided arc structure and transmission structure - Google Patents

Abstract

The embodiment of the disclosure discloses a bevel gear with a double-sided arc structure and a transmission structure. Wherein, the bevel gear comprises gear teeth and tooth sockets which are repeatedly arranged along the circumferential direction; an extension line of the extending direction of the gear teeth is intersected with the axis of the bevel gear, a first included angle is formed between the extension line and the axis, and the first included angle is larger than 0 degrees and smaller than 90 degrees; on the cross section of the bevel gear, the gear teeth are provided with first meshing lines which are convex outwards, the first meshing lines are circular arcs, the tooth sockets are provided with second meshing lines which are concave inwards, and the second meshing lines are circular arcs; the shape of each cross section of the bevel gear is consistent along the axis direction of the bevel gear, and the radius of the first meshing line and the radius of the second meshing line are gradually increased.

Description

Bevel gear with double-sided arc structure and transmission structure

Technical Field

The present disclosure relates to the field of mechanical structures, and in particular, to a bevel gear with a double-sided arc structure and a transmission structure.

Background

Bevel gears, also known as bevel gears or bevel gears, by means of which the direction of transmission can be changed. The inventors found that the bevel gears of the prior art have the following problems: (1) Involute meshing is adopted between bevel gears, so that the bevel gears are always worn by wires, are not wear-resistant, and have the service life to be improved; (2) Bevel gears can be machined only through conventional hobbing, gear grinding, gear shaping, linear cutting and other modes, machining equipment needs to be diversified, machining precision is high, cutters need to be customized, cutter customization time is long, design and money modification are inconvenient, design period is long, and average cost is high.

Disclosure of Invention

In view of this, the embodiment of the disclosure provides a bevel gear with a double-sided arc structure and a transmission structure, which at least partially prolongs the service life and reduces the processing difficulty and the processing cost.

In a first aspect, an embodiment of the present disclosure provides a bevel gear with a double-sided arc structure, which adopts the following technical scheme:

the bevel gear comprises gear teeth and tooth grooves which are repeatedly distributed along the circumferential direction;

an extension line of the extending direction of the gear teeth is intersected with the axis of the bevel gear, a first included angle is formed between the extension line and the axis, and the first included angle is larger than 0 degrees and smaller than 90 degrees;

on the cross section of the bevel gear, the gear teeth are provided with first meshing lines which are convex outwards, the first meshing lines are circular arcs, the tooth sockets are provided with second meshing lines which are concave inwards, and the second meshing lines are circular arcs;

the shape of each cross section of the bevel gear is consistent along the axis direction of the bevel gear, and the radius of the first meshing line and the radius of the second meshing line are gradually increased.

Optionally, in a cross section of the bevel gear, a radius of the second meshing line is slightly greater than or equal to a radius of the first meshing line.

Optionally, the bevel gear only includes the gear teeth and the gear slots, and in a cross section of the bevel gear, a center of arc of the first meshing line and a center of arc of the second meshing line are the same as a distance between centers of the bevel gear.

Optionally, the bevel gear further comprises a gear tooth connection part located between the gear teeth and the gear tooth grooves, a first distance is provided between the arc center of the first meshing line and the center of the bevel gear, a second distance is provided between the arc center of the second meshing line and the center of the bevel gear, and the second distance is smaller than the first distance.

Optionally, on the cross section of the bevel gear, the gear tooth connecting portion includes a first connecting line protruding outwards and a second connecting line recessed inwards, the first connecting line is connected with the gear teeth, the second connecting line is connected with the tooth grooves, and the first connecting line and the second connecting line are arc lines.

Optionally, the first connecting line is an arc line co-rounded with the first meshing line, and the second connecting line is an arc line co-rounded with the second meshing line.

Optionally, the first meshing line and the second meshing line are arc lines with an arc degree pi.

Optionally, on a circular surface perpendicular to the axis of the bevel gear and centered on the axis, the projected extension direction of the gear teeth is a radial direction of the circular surface passing through one end of the gear teeth.

Optionally, on a circular surface perpendicular to the axis of the bevel gear and centered on the axis, at least a portion of the projected extension direction of the gear teeth and a radial direction of the circular surface passing through one end of the gear teeth have a second included angle, and the second included angle is greater than 0 ° and less than 90 °.

Optionally, on a circular surface perpendicular to the axis of the bevel gear and centered on the axis, the projected extension path of the gear teeth is a curve, a broken line or a straight line.

Optionally, the bevel gear comprises at least two of the gear teeth.

In a second aspect, embodiments of the present disclosure further provide a transmission structure including two or more bevel gears according to any one of the preceding claims, the two bevel gears being intermeshed.

Optionally, the transmission structure further comprises at least one transmission element and/or structural member, which is integrally formed with the bevel gear.

The embodiment of the disclosure provides a bevel gear and a transmission structure based on a double-sided arc structure, wherein the bevel gear comprises gear teeth and tooth grooves which are repeatedly arranged along the circumferential direction, on one hand, on the cross section of the bevel gear, the gear teeth are provided with first meshing lines protruding outwards, all the first meshing lines form first meshing surfaces in the extending direction of the gear teeth, and likewise, all the second meshing lines form second meshing surfaces in the extending direction of the gear teeth, in the transmission process of the bevel gear matched with other bevel gears, the first meshing surfaces or the second meshing surfaces are meshed with other bevel gears, and the first meshing surfaces or the second meshing surfaces are meshed with the other bevel gears through the meshing surfaces, so that the surface is worn in the transmission process, the contact area is increased, the wear resistance is improved, the service life is effectively prolonged, the tooth shape of the gear teeth is firmer, the gear teeth can be made bigger and firmer under the same modulus, and the strength and the wear resistance are improved; on the other hand, because on the cross section of bevel gear, first meshing line and second meshing line are the circular arc line, do not have the undercut phenomenon, and can also process the ring gear through milling the mode, use standard machining center and turn-milling compound digit control machine tool can, the cutter need not a large amount of special customization, shortens the time of proofing greatly, reduces to professional equipment dependence, reduction in production cost.

The foregoing description is only an overview of the disclosed technology, and may be implemented in accordance with the disclosure of the present disclosure, so that the above-mentioned and other objects, features and advantages of the present disclosure can be more clearly understood, and the following detailed description of the preferred embodiments is given with reference to the accompanying drawings.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present disclosure, the drawings that are needed in the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present disclosure, and other drawings may be obtained according to these drawings without inventive effort to a person of ordinary skill in the art.

FIG. 1 is a side view of a first bevel gear provided in an embodiment of the present disclosure;

FIG. 2 is a top view of a first bevel gear provided in an embodiment of the present disclosure;

FIG. 3 is a perspective view of a first bevel gear provided in an embodiment of the present disclosure;

FIG. 4 is a cross-sectional view of a first bevel gear provided by an embodiment of the present disclosure;

FIG. 5 is an enlarged partial view of a second bevel gear provided in an embodiment of the present disclosure;

FIG. 6 is a schematic view of the projected direction of extension of the teeth of a first bevel gear according to an embodiment of the present disclosure;

FIG. 7 is a side view of a third bevel gear provided in an embodiment of the present disclosure;

FIG. 8 is a top view of a third bevel gear provided in an embodiment of the present disclosure;

FIG. 9 is a perspective view of a third bevel gear provided in an embodiment of the present disclosure;

FIG. 10 is a schematic view of the projected direction of extension of the teeth of a third bevel gear provided in an embodiment of the present disclosure;

FIG. 11 is a side view of a first transmission structure provided by an embodiment of the present disclosure;

FIG. 12 is a side view of a second transmission structure provided by an embodiment of the present disclosure;

FIG. 13 is a side view of a fourth bevel gear provided by an embodiment of the present disclosure;

FIG. 14 is a top view of a fourth bevel gear provided by an embodiment of the present disclosure;

fig. 15 is a perspective view of a fourth bevel gear provided in an embodiment of the present disclosure.

Detailed Description

The present disclosure is described in further detail below with reference to the drawings and the embodiments. It is to be understood that the specific embodiments described herein are merely illustrative of the relevant content and not limiting of the present disclosure. It should be further noted that, for convenience of description, only a portion relevant to the present disclosure is shown in the drawings.

In addition, embodiments of the present disclosure and features of the embodiments may be combined with each other without conflict. The technical aspects of the present disclosure will be described in detail below with reference to the accompanying drawings in conjunction with embodiments.

Unless otherwise indicated, the exemplary implementations/embodiments shown are to be understood as providing exemplary features of various details of some ways in which the technical concepts of the present disclosure may be practiced. Thus, unless otherwise indicated, features of the various implementations/embodiments may be additionally combined, separated, interchanged, and/or rearranged without departing from the technical concepts of the present disclosure.

The use of cross-hatching and/or shading in the drawings is typically used to clarify the boundaries between adjacent components. As such, the presence or absence of cross-hatching or shading does not convey or represent any preference or requirement for a particular material, material property, dimension, proportion, commonality between illustrated components, and/or any other characteristic, attribute, property, etc. of a component, unless indicated. In addition, in the drawings, the size and relative sizes of elements may be exaggerated for clarity and/or descriptive purposes. While the exemplary embodiments may be variously implemented, the specific process sequences may be performed in a different order than that described. For example, two consecutively described processes may be performed substantially simultaneously or in reverse order from that described. Moreover, like reference numerals designate like parts.

When an element is referred to as being "on" or "over", "connected to" or "coupled to" another element, it can be directly on, connected or coupled to the other element or intervening elements may be present. However, when an element is referred to as being "directly on," "directly connected to," or "directly coupled to" another element, there are no intervening elements present. For this reason, the term "connected" may refer to physical connections, electrical connections, and the like, with or without intermediate components.

For descriptive purposes, the present disclosure may use spatially relative terms such as "under … …," under … …, "" under … …, "" lower, "" above … …, "" upper, "" above … …, "" higher "and" side (e.g., as in "sidewall"), etc., to describe one component's relationship to another (other) component as illustrated in the figures. In addition to the orientations depicted in the drawings, the spatially relative terms are intended to encompass different orientations of the device in use, operation, and/or manufacture. For example, if the device in the figures is turned over, elements described as "under" or "beneath" other elements or features would then be oriented "over" the other elements or features. Thus, the exemplary term "below" … … can encompass both an orientation of "above" and "below". Furthermore, the device may be otherwise positioned (e.g., rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. Furthermore, when the terms "comprises" and/or "comprising," and variations thereof, are used in the present specification, the presence of stated features, integers, steps, operations, elements, components, and/or groups thereof is described, but the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof is not precluded. It is also noted that, as used herein, the terms "substantially," "about," and other similar terms are used as approximation terms and not as degree terms, and as such, are used to explain the inherent deviations of measured, calculated, and/or provided values that would be recognized by one of ordinary skill in the art.

The embodiment of the present disclosure provides a bevel gear with a double-sided arc structure, specifically, as shown in fig. 1 to 4, fig. 1 is a side view of a first type of bevel gear provided by the embodiment of the present disclosure, fig. 2 is a top view of the first type of bevel gear provided by the embodiment of the present disclosure, fig. 3 is a perspective view of the first type of bevel gear provided by the embodiment of the present disclosure, fig. 4 is a cross-sectional view of the first type of bevel gear provided by the embodiment of the present disclosure, the bevel gear includes gear teeth 11 and gear grooves 12 repeatedly arranged along a circumferential direction, an extension line of an extension direction (shown by a dotted line in fig. 3) of the gear teeth 11 intersects an axis (an X direction in fig. 3) of the bevel gear, and a first included angle is formed between the extension line and the axis, and the first included angle is greater than 0 ° and less than 90 °; in the cross section of the bevel gear, the gear teeth 11 are provided with first meshing lines A which are convex outwards, the first meshing lines A are arc lines, the tooth grooves 12 are provided with second meshing lines B which are concave inwards, and the second meshing lines B are arc lines; the cross sections of the bevel gears are uniform in shape along the axis direction of the bevel gears, and the radii of the first meshing line A and the second meshing line B gradually increase.

The double-sided arc structure means that the first meshing line A and the second meshing line B are arc-shaped on the cross section of the bevel gear.

During the use of the bevel gears, the first meshing line A or the second meshing line B is meshed with other bevel gears.

The bevel gear has at least the following technical advantages:

on the one hand, on the cross section of the bevel gear, the gear teeth 11 are provided with first meshing lines A protruding outwards, all the first meshing lines A form first meshing surfaces in the extending direction of the gear teeth 11, and likewise, all the second meshing lines B form second meshing surfaces in the extending direction of the gear teeth 11;

on the other hand, because on the cross section of bevel gear, first meshing line A and second meshing line B are the circular arc line, do not have the undercut phenomenon, and can also process the ring gear through milling mode, use standard machining center with turn milling compound digit control machine tool can, the cutter need not a large amount of special customization, shorten the time of drawing a design greatly, reduce to professional equipment dependence, reduction in production cost.

Additionally, it should be added that the bevel gear in the embodiments of the present disclosure also has the following technical advantages: the stress is uniform; the contact area is large, and the wear resistance is improved; by tightly meshing the meshing surfaces, the running precision is improved, the stressed area is doubled or even higher than that of the prior art, and the bearing capacity is improved; and the measurement accuracy error is convenient.

In the disclosed embodiment, as shown in fig. 4, the radius of the second meshing line B may be greater than, equal to, or less than the radius of the first meshing line a in the cross section of the bevel gear. Alternatively, in the disclosed embodiment, as shown in fig. 3, the radius of the second meshing line B is slightly greater than or equal to the radius of the first meshing line a, i.e., the gear teeth 11 and the tooth slots 12 thereon are similar in size for bevel gears. The size range "slightly larger" can be selected by those skilled in the art according to practical needs, for example, the radius of the second meshing line B is 0.05 μm, 0.1 μm, 0.2 μm, 0.5 μm, etc. larger than the radius of the first meshing line a.

Alternatively, in the embodiment of the present disclosure, as shown in fig. 4, the bevel gear includes only the gear teeth 11 and the gear grooves 12, and in the cross section of the bevel gear, the arc center of the first meshing line a (shown as the lower black point in fig. 4) and the arc center of the second meshing line B (shown as the upper black point in fig. 4) are the same distance from the center of the bevel gear (shown as the middle black point in fig. 4), that is, in the orientation shown in fig. 4, the arc center of the first meshing line a and the arc center of the second meshing line B are on the same circumference (shown as the dashed arc in fig. 4) centered on the center of the bevel gear. In this case, during the transmission of the bevel gear, the operation is stable and the vibration is small.

Optionally, in an embodiment of the present disclosure, as shown in fig. 5, fig. 5 is a partial enlarged view of a second bevel gear provided in the embodiment of the present disclosure, the bevel gear further includes a gear tooth connection portion 13 located between the gear tooth 11 and the gear tooth groove 12, and in a cross section of the bevel gear, a first distance is provided between an arc center (shown as a left black point in fig. 5) of the first meshing line a and a center (not shown in fig. 5) of the bevel gear, and a second distance is provided between an arc center (shown as a right black point in fig. 5) of the second meshing line B and the center of the bevel gear, the second distance being smaller than the first distance, that is, in an orientation of the cross section of the bevel gear, the arc center of the first meshing line a and the arc center of the second meshing line B are located on different circumferences centered on the center of the bevel gear. In this case, there is a speed change and vibration effect during the transmission of the bevel gear.

Further, as shown in fig. 5, in the cross section of the bevel gear, the tooth connecting portion 13 includes a first connecting line 131 protruding outward and a second connecting line 132 recessed inward, which are connected end to end, the first connecting line 131 being connected to the tooth 11, the second connecting line 132 being connected to the tooth slot 12, the first connecting line 131 and the second connecting line 132 being arc lines. With the above configuration of the cogged-wheel coupling portion 13, the meshing area between the bevel gears can be further increased.

Further, as shown in fig. 5, the first connecting line 131 is an arc co-circular with the first engaging line a, and the second connecting line 132 is an arc co-circular with the second engaging line B. In this case, during the transmission of the bevel gears, the first connection line 131 or the second connection line 132 is also engaged with other bevel gears, thereby further increasing the engagement area between the bevel gears.

Alternatively, as shown in fig. 4 and 5, the first meshing line a and the second meshing line B in the embodiment of the present disclosure are each a circular arc line having a radian pi, that is, half of the entire circumference, so that the meshing area between bevel gears is further increased.

Alternatively, the bevel gears in the embodiments of the present disclosure may be straight bevel gears or helical bevel gears.

When the bevel gear is a straight bevel gear as shown in fig. 1 to 3, as shown in fig. 6, fig. 6 is a schematic view illustrating an extending direction of a projection of a gear tooth of the first bevel gear according to an embodiment of the present disclosure, on a circular surface (indicated by a dashed circle in fig. 6) perpendicular to an axis of the bevel gear and centered on the axis, an extending direction of a projection of the gear tooth 11 (indicated by a dashed line in fig. 6) is a radial direction of the circular surface passing through one end of the gear tooth 11. Only one tooth 11 is shown in fig. 6 as an example.

Fig. 7 is a side view of a third bevel gear according to an embodiment of the present disclosure, fig. 8 is a top view of the third bevel gear according to an embodiment of the present disclosure, fig. 9 is a perspective view of the third bevel gear according to an embodiment of the present disclosure (the dashed line in fig. 9 is the extending direction of the gear teeth), when the bevel gear is a helical bevel gear as shown in fig. 7, fig. 8 and fig. 9, as shown in fig. 10, fig. 10 is a schematic view of the extending direction of the projection of the gear teeth of the third bevel gear according to an embodiment of the present disclosure, on a circular surface (the dashed line circle in fig. 10) perpendicular to the axis of the bevel gear and centered on the axis, at least a portion of the extending direction of the projection of the gear teeth 11 (the dashed line in fig. 10) has a second included angle with the radial direction of one end of the circular surface passing through the gear teeth 11, the second included angle being greater than 0 ° and less than 90 °, and optionally 10 ° to 45 °. Only one tooth 11 is shown in fig. 10 as an example.

Alternatively, the projected extension path of the gear teeth 11 on a circular surface perpendicular to the axis of the bevel gear and centered on the axis is a curve (e.g., an arc), a broken line (e.g., a chevron), or a straight line. In the example shown in fig. 10, the projected extending path of the gear teeth 11 is a straight line on a circular surface perpendicular to the axis of the bevel gear and centered on the axis.

Optionally, the bevel gear in embodiments of the present disclosure includes at least two gear teeth 11, e.g., 2, 3, 4, 5, 8, 10, 15, 20, etc., with a wider range of selectable numbers of gear teeth 11. The gear ring in the prior art is involute meshing, if the number of gear teeth is small, the undercut problem can occur, and the meshing line of the bevel gear in the embodiment of the disclosure is an arc line, so that the undercut problem can not occur no matter a plurality of gear teeth 11 are arranged.

In addition, the embodiment of the present disclosure further provides a transmission structure, as shown in fig. 11 and fig. 12, where fig. 11 is a side view of a first transmission structure provided by the embodiment of the present disclosure, and fig. 12 is a side view of a second transmission structure provided by the embodiment of the present disclosure, where the transmission structure includes two or more bevel gears of any one of the two bevel gears, and the two bevel gears are meshed with each other.

When the magnitude of the first angle between the extension line of the gear teeth 11 of the bevel gears and the axis is changed, the angle of engagement between the two bevel gears is changed, and can be selected according to actual needs by those skilled in the art. An engagement angle of greater than 0 degrees, less than or equal to 90 degrees, for example, 30 degrees, 45 degrees, 60 degrees, 90 degrees, etc., may be achieved between two bevel gears in embodiments of the present disclosure.

In the example shown in fig. 11, both bevel gears are spur bevel gears, in particular two identical bevel gears as shown in fig. 1-3. In the example shown in fig. 12, both bevel gears are bevel gears, but they are different bevel gears, and a person skilled in the art may set specific parameters of the two bevel gears according to actual needs so that the two bevel gears can mesh. Specifically, in the example shown in fig. 12, one of the bevel gears is a bevel gear as shown in fig. 7 to 9, in the orientation shown in fig. 8, the gear teeth are inclined counterclockwise by a certain angle, the other bevel gear is a bevel gear as shown in fig. 13 to 15, fig. 13 is a side view of a fourth bevel gear provided by an embodiment of the present disclosure, fig. 14 is a top view of a fourth bevel gear provided by an embodiment of the present disclosure, and fig. 15 is a perspective view of a fourth bevel gear provided by an embodiment of the present disclosure, the gear teeth are inclined clockwise by the same angle, and the two achieve meshing.

Optionally, the transmission structure in the embodiments of the present disclosure further includes at least one transmission element and/or structural member, which is integrally formed with the bevel gear 10. For example, in the example shown in fig. 1, the transmission structure further includes a gear drive shaft 14, and the gear drive shaft 14 is integrally formed with the bevel gear.

Because the bevel gears of the disclosed embodiments may be machined by milling, the transmission elements and/or structural members of the gear drive shaft 14, etc., may be integrally formed with the bevel gear 10. Of course, when other parts are needed to be matched with the bevel gear, the bevel gear and the bevel gear can be made into an integral part, the number of assembly stages is reduced, the number of parts is greatly reduced, the number of assembly stages is greatly reduced, the multi-stage assembly precision error is greatly reduced, various comprehensive instabilities are greatly reduced, the number of fasteners or positioning parts is greatly reduced, and the integral part has stronger rigidity, and has stronger integral structure precision and retentivity.

The prior art old-fashioned gears are limited by several conventional processing methods, such as making other parts on the gears into separate parts, and then assembling the separate parts. When each stage of assembly is assembled, precision errors (concentricity, cylindricity, position degree, verticality, levelness, parallelism and the like) are generated, the errors can be accumulated along with the increase of part cooperation, or single parts are possibly qualified, and the whole multi-layer multi-stage assembly is disqualified to cause precision super tolerance, so that various comprehensive instabilities are generated; the multi-stage assembly needs to use a fastener or a positioning piece, or the working time is increased along with the time, the precision retention degree of the multi-stage assembly overall structure is reduced, and the rigidity is reduced.

In the description of the present specification, reference to the terms "one embodiment/manner," "some embodiments/manner," "example," "a particular example," "some examples," etc., means that a particular feature, structure, material, or characteristic described in connection with the embodiment/manner or example is included in at least one embodiment/manner or example of the application. In this specification, the schematic representations of the above terms are not necessarily for the same embodiment/manner or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments/modes or examples. Furthermore, the various embodiments/modes or examples described in this specification and the features of the various embodiments/modes or examples can be combined and combined by persons skilled in the art without contradiction.

Furthermore, the terms "first," "second," and the like, are used for descriptive purposes only and are not to be construed as indicating or implying a relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include at least one such feature. In the description of the present application, the meaning of "plurality" means at least two, for example, two, three, etc., unless specifically defined otherwise.

It will be appreciated by those skilled in the art that the above-described embodiments are merely for clarity of illustration of the disclosure, and are not intended to limit the scope of the disclosure. Other variations or modifications will be apparent to persons skilled in the art from the foregoing disclosure, and such variations or modifications are intended to be within the scope of the present disclosure.

Claims (13)

1. The bevel gear with the double-sided arc structure is characterized by comprising gear teeth and tooth grooves which are repeatedly arranged along the circumferential direction;

an extension line of the extending direction of the gear teeth is intersected with the axis of the bevel gear, a first included angle is formed between the extension line and the axis, and the first included angle is larger than 0 degrees and smaller than 90 degrees;

on the cross section of the bevel gear, the gear teeth are provided with first meshing lines which are convex outwards, the first meshing lines are circular arcs, the tooth sockets are provided with second meshing lines which are concave inwards, and the second meshing lines are circular arcs;

the shape of each cross section of the bevel gear is consistent along the axis direction of the bevel gear, and the radius of the first meshing line and the radius of the second meshing line are gradually increased.

2. The bevel gear according to claim 1, wherein the radius of the second meshing line is slightly greater than or equal to the radius of the first meshing line in a cross section of the bevel gear.

3. The bevel gear according to claim 1 or 2, wherein the bevel gear comprises only the teeth and the tooth grooves, and wherein the arc center of the first meshing line and the arc center of the second meshing line are the same distance from the center of the bevel gear in a cross section of the bevel gear.

4. The bevel gear according to claim 1 or 2, further comprising a cogged connection between the cog and the cog, wherein in a cross section of the bevel gear a first distance is provided between the centre of arc of the first meshing line and the centre of the bevel gear and a second distance is provided between the centre of arc of the second meshing line and the centre of the bevel gear, the second distance being smaller than the first distance.

5. The bevel gear according to claim 4 wherein said cogged connection comprises an outwardly convex first connection wire and an inwardly concave second connection wire connected end to end in cross section of said bevel gear, said first connection wire being connected to said cog and said second connection wire being connected to said spline, said first connection wire and said second connection wire being arcuate.

6. The bevel gear of claim 5 wherein the first connection line is a circular arc co-circular with the first meshing line and the second connection line is a circular arc co-circular with the second meshing line.

7. A bevel gear according to claim 1 or 2 wherein the first and second meshing lines are each an arc of a circle having an arc of pi.

8. A bevel gear according to claim 1 or 2 wherein the projected extension of the gear teeth on a circular face perpendicular to the axis of the bevel gear and centered on the axis is radial to the circular face past one end of the gear teeth.

9. Bevel gear according to claim 1 or 2, wherein on a circular surface perpendicular to the axis of the bevel gear and centered on said axis, at least a part of the projected extension of the gear teeth has a second angle with the radial direction of the circular surface passing through one end of the gear teeth, said second angle being larger than 0 ° and smaller than 90 °.

10. The bevel gear according to claim 9, wherein the projected extension path of the gear teeth is a curve, a broken line or a straight line on a circular surface perpendicular to the axis of the bevel gear and centered on the axis.

11. Bevel gear according to claim 1 or 2, wherein the bevel gear comprises at least two of the gear teeth.

12. A transmission structure comprising two bevel gears according to any one of claims 1 to 11, wherein the bevel gears are intermeshed.

13. The transmission structure according to claim 12, further comprising at least one transmission element and/or structural member, said transmission element and/or structural member being integrally formed with said bevel gear.