CN220816435U - Transmission assembly and speed reducer - Google Patents

Abstract

The utility model discloses a transmission assembly and a speed reducer. The transmission assembly comprises a first transmission wheel and a second transmission wheel, wherein the outer peripheral side surface of the first transmission wheel is provided with a first tooth part in a surrounding mode, the first tooth part is provided with at least one first tooth, the inner peripheral side surface of the second transmission wheel is provided with a second tooth part in a surrounding mode, the second tooth part is provided with at least one second tooth, and the second tooth is provided with a notch at the tooth root; the transmission assembly is configured such that the first transmission wheel and the second transmission wheel are engaged and connected by the first tooth portion and the second tooth portion, and such that at least a portion of the tooth tip of the first tooth is located at an opening of the recess of the corresponding engaged one of the second teeth. Above-mentioned drive assembly carries out the transmission through the mode of tooth meshing, can avoid because interference fit leads to the problem of drive wheel deformation, moreover, when first drive wheel and second drive wheel meshing, the tooth top of first tooth can support and lean on the notch of second tooth for form certain clearance between first tooth and the second tooth, can prevent that the tooth top of first tooth from interfering.

Description

Transmission assembly and speed reducer

Technical Field

The utility model relates to the field of speed reduction transmission, in particular to a transmission assembly and a speed reducer.

Background

Compared with the traditional planetary speed reducer, the RV speed reducer has the characteristics of high precision, high reliability and low back clearance. RV speed reducer adopts parallel shaft transmission+planetary transmission+cycloid transmission combination mode, and the driven gear of parallel shaft transmission is connected with the sun gear of planetary transmission, transmits the torque of parallel shaft transmission to planetary gear train, and is formed into duplex gear by the driven gear of parallel shaft transmission and sun gear of planetary transmission. The connection design of duplex gear is not good, and light then RV speed reducer transmission precision worsens, can lead to the arm to skid when receiving the impact under extreme circumstances, falls, produces the accident.

The conventional connection design method of the duplex gear is cylindrical interference connection and shear screws, and the cylindrical interference connection transmits torque through friction of contact surfaces and large interference, and the large interference can influence the tooth form precision of the thin-wall sun gear, so that the meshing precision of the planetary gear train is poor.

Disclosure of utility model

The present utility model provides a transmission assembly and a reduction gear to solve at least one technical problem as described above.

A transmission assembly for a decelerator according to an embodiment of the present utility model includes:

The first driving wheel is circumferentially provided with a first tooth part on the outer circumferential side surface, and the first tooth part is provided with at least one first tooth and;

The inner peripheral side surface of the second driving wheel is provided with a second tooth part in a surrounding mode, the second tooth part is provided with at least one second tooth, and the second tooth is provided with a notch at the tooth root;

The transmission assembly is configured such that the first transmission wheel and the second transmission wheel are engaged and connected through the first tooth portion and the second tooth portion, and such that at least part of the tooth top of the first tooth is located at an opening of a recess of one of the second teeth that is engaged correspondingly.

Above-mentioned drive assembly carries out the transmission through the mode of tooth meshing, can avoid because interference fit leads to the problem of drive wheel deformation, moreover, when first drive wheel and second drive wheel meshing, the tooth top of first tooth can support and lean on the notch of second tooth for form certain clearance between first tooth and the second tooth, can prevent the problem that the tooth top of first tooth interfered.

In certain embodiments, the first tooth is a spline structure. Therefore, structural deformation between the driving wheels can be avoided, and meshing precision of the first driving wheel and other gear tooth structures can be prevented from being influenced.

In some embodiments, the first driving wheel is configured such that a center of rotation of the first driving wheel is determined by a tip circle of the first tooth portion, and the first tooth portion and the second tooth portion are rotatable around the center of rotation. Therefore, the radial positioning precision between the first driving wheel and the second driving wheel can be ensured, and the meshing precision and the transmission precision can be further effectively ensured.

In some embodiments, the tooth top surface of the first tooth conforms to the tooth bottom surface of the second tooth, and the tooth side of the second tooth forms a working section from the tooth top surface edge of the second tooth to the portion of the recess, through which the second tooth abuts the first tooth. Thus, the axial positioning of the second driving wheel on the first driving wheel can be facilitated.

In certain embodiments, the recess opens into a root surface of the second tooth. In this way, the position of the notch can be flexibly selected.

In certain embodiments, the recess opens on a portion of the second tooth proximate to a root surface of the second tooth; the side wall of the recess formed by the second tooth part is divided into a first side wall section and a second side wall section, the first side wall section extends from the tooth side of the second tooth to a direction away from the first tooth, and the second side wall section extends from the first side wall section to a direction close to the tooth root surface of the second tooth. Thus, the influence of the notch on the structural strength of the second tooth can be reduced on the premise of avoiding the interference of the tooth tops.

In some embodiments, the first sidewall segment is a straight line segment, the extending direction of the first sidewall segment corresponds to a radial direction of a notch starting point relative to a center of rotation, the notch starting point is a connection point between tooth sides of the first sidewall segment and the second tooth, and the first tooth portion and the second tooth portion are capable of rotating around the center of rotation. Thus, the notch can be conveniently machined.

In certain embodiments, the position of the notch origin on the second tooth portion can be determined by the following formula:

hk＝rk-ra2，

Wherein hk is the radial length of the working section relative to the rotating circle center, rk is the circle radius of the notch starting point relative to the rotating circle center, ra2 is the radius of the addendum circle of the second driving wheel, T is the bearing torque of the second tooth part, ψ is the uneven load coefficient of the second tooth part, Z is the number of teeth of the second tooth, L is the working length of the second tooth in the tooth width direction, and [ p ] is the material allowable pressure. In this way, the second tooth can be ensured to meet the corresponding load working condition requirement.

In some embodiments, the radial length of the working segment relative to the center of rotation ranges from 0.8Mn to 1.2Mn, with Mn being the normal modulus.

In certain embodiments, the linear trajectory of the first sidewall segment can be determined by the location of the notch start point, the pressure angle of the second tooth at the notch start point.

In some embodiments, the second side wall section is an arc section, and the arc track of the second side wall section is tangent to the straight line track of the first side wall section and the root circle of the second tooth portion respectively.

In certain embodiments, the arc length of the second sidewall segment has a value in the range of 0.1Mn to 1Mn, mn being the normal modulus.

A decelerator according to an embodiment of the present utility model includes:

The transmission assembly of any of the above embodiments.

Above-mentioned reduction gear, through the mode of tooth meshing transmission, can avoid leading to the problem that the drive wheel warp because interference fit, moreover, when first drive wheel and second drive wheel mesh, the tooth top of first tooth can support and lean on the notch of second tooth for form certain clearance between first tooth and the second tooth, can prevent the problem that the tooth top of first tooth interfered.

Additional aspects and advantages of the utility model will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the utility model.

Drawings

The foregoing and/or additional aspects and advantages of the present utility model will become apparent and readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings, in which:

FIG. 1 is a schematic structural view of a transmission assembly according to an embodiment of the present utility model;

FIG. 2 is a schematic view of a portion of the structure of a first tooth portion and a second tooth portion according to an embodiment of the present utility model;

FIG. 3 is a schematic view of a portion of a first tooth portion according to an embodiment of the present utility model;

FIG. 4 is a schematic view of a portion of a second tooth portion according to an embodiment of the present utility model;

FIG. 5 is another partial schematic view of a second tooth portion according to an embodiment of the present utility model;

FIG. 6 is an enlarged view of section I of FIG. 2;

FIG. 7 is a schematic diagram of determining the design range of a notch in an embodiment of the present utility model.

Reference numerals for main elements:

A transmission assembly 100;

the first driving wheel 11, the first tooth part 12, the first tooth 13 and the bulge 14;

the second drive wheel 21, the second tooth portion 22, the second tooth 23, the recess 24, the first side wall section 25, the second side wall section 26.

Detailed Description

In the description of the present utility model, portions of the disclosure have been represented by corresponding drawings, wherein like or similar reference numerals indicate like or similar elements or elements having like or similar functions throughout. The following description is exemplary in nature and is in no way intended to limit the utility model, its application, or the like.

In the description of the present utility model, many different matters or examples are disclosed for realizing the different structures of the present utility model. In order to simplify the present disclosure, components and arrangements of specific examples are described below. They are, of course, merely examples and are not intended to limit the utility model.

Furthermore, the present utility model may repeat reference numerals and/or letters in the various examples, which are for the purpose of brevity and clarity, and which do not themselves indicate the relationship between the various instances and/or arrangements discussed.

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 one or more of the described features. In the description of the present utility model, the meaning of "a plurality" is two or more, unless explicitly defined otherwise.

In the description of the present utility model, it should be understood that terms such as "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", etc. used for indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the drawings, only for convenience of describing the present utility model and for understanding the corresponding embodiments, and do not indicate or imply that the apparatus or element to be referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus the terms used for indicating the orientation or positional relationship should not be construed as limiting the present utility model.

In the description of the present utility model, unless explicitly stated and limited otherwise, a first feature "above" or "below" a second feature may include both the first and second features being in direct contact, or may include both the first and second features not being in direct contact but being in contact by another feature therebetween. Moreover, a first feature being "above," "over" and "on" a second feature includes the first feature being directly above and obliquely above the second feature, or simply indicating that the first feature is higher in level than the second feature. The first feature being "under", "below" and "beneath" the second feature includes the first feature being directly under and obliquely below the second feature, or simply means that the first feature is less level than the second feature.

In the description of the present utility model, it should be noted that the terms "mounted," "connected," and "coupled" are to be construed broadly, as well as, for example, fixedly coupled, detachably coupled, or integrally coupled, unless otherwise specifically indicated and defined. Either mechanically or electrically. Can be directly connected or indirectly connected through an intermediate medium, and can be communicated with the inside of two elements or the interaction relationship of the two elements. The specific meaning of the above terms in the present utility model can be understood by those of ordinary skill in the art according to the specific circumstances.

Referring to fig. 1 and 2, a transmission assembly 100 for a decelerator of the present utility model may include a first transmission wheel 11 and a second transmission wheel 21.

The outer circumferential side of the first transmission wheel 11 is provided with a first tooth 12, the first tooth 12 having at least one first tooth 13.

The inner circumferential side of the second transmission wheel 21 is circumferentially provided with a second tooth 22, the second tooth 22 having at least one second tooth 23, the second tooth 23 being provided with a recess 24 at the root.

The transmission assembly 100 is configured such that the first transmission wheel 11 and the second transmission wheel 21 are engaged and connected by the first tooth portion 12 and the second tooth portion 22, and such that at least part of the tooth tops of the first teeth 13 is located at the opening of the recess 24 of the corresponding engaged one of the second teeth 23.

The transmission assembly 100 performs transmission in a gear tooth meshing manner, so that the problem of deformation of the transmission wheel due to interference fit can be avoided, and when the first transmission wheel 11 and the second transmission wheel 21 are meshed, the tooth tops of the first teeth 13 can abut against the notch 24 of the second teeth 23, so that a certain gap is formed between the first teeth 13 and the second teeth 23, and the problem of tooth top interference of the first teeth 13 can be prevented.

The first driving wheel 11 and the second driving wheel 21 can realize the effect of coaxial rotation through the gear tooth meshing mode. In fig. 1, the axes of rotation of the first and second drive wheels 11, 21 are each denoted X.

The first transmission wheel 11 and the second transmission wheel 21 are basically in a circular ring-shaped structure. In fig. 1, the side of the first driving wheel 11 facing the rotation axis may be an inner circumferential side of the first driving wheel 11, and the side of the first driving wheel 11 facing away from the rotation axis may be an outer circumferential side of the first driving wheel 11; the side of the second driving wheel 21 facing the rotation axis may be an inner peripheral side of the second driving wheel 21, and the side of the second driving wheel 21 facing away from the rotation axis may be an outer peripheral side of the first driving wheel 11. The second driving wheel 21 may be sleeved with the first driving wheel 11 through an annular hole located at the inner side, so that the outer circumferential side surface of the first driving wheel 11 and the inner circumferential side surface of the second driving wheel 21 may be in contact.

In fig. 1, the direction A1 may be the assembly direction of the second transmission wheel 21 with respect to the first transmission wheel 11, or, in other words, the second transmission wheel 21 may be assembled on the first transmission wheel 11 along the direction A1. The first transmission wheel 11 may comprise a projection 14. The projection 14 may be provided on the outer peripheral side of the first transmission wheel 11. When the second driving wheel 21 is assembled on the first driving wheel 11, the protrusion 14 is located at one side of the second driving wheel 21 along the direction A1, so that the protrusion 14 can block the movement of the second driving wheel 21 along the direction A1, and can play a role in limiting the assembly of the second driving wheel 21.

Referring to fig. 1 and 2 in combination, in fig. 2, the first tooth 12 may be disposed around the rotation axis on the outer circumferential side of the first transmission wheel 11 so that the first tooth 12 may serve as the outer teeth of the first transmission wheel 11; the second tooth 22 can be arranged circumferentially around the axis of rotation on the inner circumferential side of the second drive wheel 21, so that the second tooth 22 can act as an inner tooth of the second drive wheel 21. The meshing connection of the internal teeth and the external teeth enables the first transmission wheel 11 and the second transmission wheel 21 to achieve a transmission effect in the form of a double gear.

Further, in fig. 2, the first tooth portion 12 may have a plurality of first teeth 13, and the second tooth portion 22 may have a plurality of second teeth 23. When the first tooth 13 and the second tooth 23 are engaged, the tip of the first tooth 13 can be brought close to the root of the second tooth 23, and the second tooth portion 22 is provided with a notch 24 at a position located at the root of the second tooth 23. The recess 24 is formed in a concave configuration on the second tooth portion 22 such that the second tooth 23 forms a gap between the position of the recess 24 and the first tooth 13. In this way, in practical application, even if the tip of the first tooth 13 interferes with the second tooth 23, the tooth root of the second tooth 23 is not grooved by the first tooth 13 due to the clearance formed by the notch 24, so that the problem of the tip interference of the first tooth 13 can be effectively prevented.

Referring to fig. 1, the first tooth portion 12 may be a spline structure.

In this way, structural deformations between the driving wheels can be avoided, and the meshing accuracy of the first driving wheel 11 with other gear tooth structures can be avoided.

Specifically, in fig. 1, the first driving wheel 11 may be disposed to extend in the A1 direction so as to have a substantially columnar structure. The first tooth 12 may be machined on the outer surface of the cylindrical structure of the first transmission wheel 11. The first tooth part 12 is arranged into a spline structure, and the first tooth part is assembled in a press fit or hot sleeve mode, so that the problem that the first transmission wheel 11 and the second transmission wheel 21 deform due to extrusion of the structure in the interference connection process is avoided, and the spline structure has the advantages of high processing efficiency, high precision and low cost, and is beneficial to reducing the influence of assembly difficulty and part deformation on gear engagement.

Referring to fig. 1 and 2, the first driving wheel 11 may be configured such that a rotation center of the first driving wheel 11 is determined by a tip circle of the first tooth 12, and the first tooth 12 and the second tooth 22 can rotate around the rotation center.

In this way, the radial positioning accuracy between the first transmission wheel 11 and the second transmission wheel 21 can be ensured, and the engagement accuracy and the transmission accuracy can be further effectively ensured.

Specifically, the first tooth portion 12 is integrally formed so as to be protruded on the outer peripheral side surface of the first transmission wheel 11. The first transmission wheel 11 may be centered in a large diameter, and the center of the tip circle formed by the tips of all the first teeth 13 in the first tooth portion 12 is used as the center of the rotation of the first transmission wheel 11. In fig. 1, the center of rotation may be denoted as O, and the center of rotation is located on the rotation axis.

In some cases, the first driving wheel 11 may be meshed with other gear tooth structures, and since the first driving wheel 11 is basically in a columnar structure and has a wall thickness, the wall surface of the first driving wheel 11 needs to be extruded and deformed in an interference connection manner, so that the shape of the structure of the first driving wheel 11 meshed with other gear tooth structures can be affected, and thus, the meshing precision and the transmission precision between the first driving wheel 11 and other gear tooth structures can be affected. The rotation circle center is determined by adopting a large-diameter centering mode for the spline structure, so that the radial positioning precision during assembly can be improved when the first transmission wheel 11 and the second transmission wheel 21 are assembled, and further the meshing precision and the transmission precision between the first transmission wheel 11 and other gear tooth structures can be effectively ensured.

Referring to fig. 2, the top surface of the first tooth 13 may be in contact with the bottom surface of the second tooth 23. The tooth side of the second tooth 23 forms a working section from the top edge of the second tooth 23 to the recess 24. The second tooth 23 abuts the first tooth 13 through the working section.

In this way, the axial positioning of the second transmission wheel 21 on the first transmission wheel 11 is facilitated.

Referring to fig. 3 and 4, the top surface of the first tooth 13 may be denoted as S1 and the bottom surface of the second tooth 23 may be denoted as S2. The top surface of the first tooth 13 may be formed by removing the top of the first tooth 13, so that the edge of the surface of the first tooth 13 may be increased, so that the second tooth portion 22 is more easily limited by the edge shape of the first tooth 13, thereby playing a role in axially positioning the second driving wheel 21, and during assembly, the second driving wheel 21 may be conveniently axially positioned.

Referring to fig. 5, a recess 24 may be provided in the root surface of the second tooth 23.

In this way, the position of the recess 24 can be flexibly selected.

In addition, in fig. 5, the side wall forming the recess 24 on the tooth root surface of the second tooth 23 may have an arc-like structure, so that the stress distribution at the tooth root of the second tooth 23 can be changed when the tooth tip of the first tooth 13 abuts against the tooth root of the second tooth 23, and sufficient structural strength can be maintained.

Referring to fig. 2 and 6, the recess 24 may be provided in a portion of the second tooth 23 adjacent to the root surface of the second tooth 23.

The side wall of the second tooth 22 forming the recess 24 may be divided into a first side wall section 25 and a second side wall section 26. The first sidewall section 25 may extend from the tooth side of the second tooth 23 in a direction away from the first tooth 13. The second sidewall segment 26 may extend from the first sidewall segment 25 in a direction proximate to the root surface of the second tooth 23.

In this way, the influence of the notch 24 on the structural strength of the second tooth 23 can be reduced while avoiding the interference of the tooth tip.

In fig. 6, a portion of the first sidewall section 25 may be formed extending in the A2 direction from the tooth side of the second tooth 23. In the recess 24, the first side wall section 25 and the second side wall section 26 may be smoothly connected. The second side wall section 26 may start to extend at the point where it connects with the first side wall section 25. The end of the second sidewall segment 26 extending may extend substantially in the A3 direction.

In the case where the notch 24 is located on the second tooth 23 near the portion of the tooth root surface of the second tooth 23, interference of the first tooth 13 with the second tooth 23 in the circumferential direction can be prevented, and reduction of the contact area on the tooth side of the second tooth 23 for abutment with the first tooth 13 can be avoided, so that the second tooth 23 can withstand a larger force from the first tooth 13, whereby the influence on the structural strength of the second tooth 23 can be reduced.

Referring to fig. 6, the first sidewall segment 25 may be a straight segment. The direction of extension of the first sidewall segment 25 may correspond to the radial direction of the starting point of the recess 24 with respect to the center of rotation. The notch 24 may start at the connection point between the first sidewall section 25 and the flanks of the second tooth 23. The first tooth 12 and the second tooth 22 are rotatable about the center of rotation.

In this manner, machining of the recess 24 may be facilitated.

In fig. 6, the first sidewall segment 25 may extend entirely in the A2 direction to form a plane. The starting point of the notch 24 may be denoted as K-point. The flanks of the second teeth 23 will connect the first sidewall segments 25 at point K.

It will be appreciated that machining of planar surfaces is simpler relative to machining of arcuate surfaces, thereby facilitating reduced difficulty in machining of the recess 24 and facilitating machining of the recess 24.

In addition, it should be noted that the description of the drawings of the first tooth portion 12 and the second tooth portion 22 in the present utility model mainly uses the axial direction along the rotation axis as the view angle. In a practical construction, the respective construction will be of such a thickness in the direction of the axis of rotation that the points depicted in the respective drawings will actually refer to the corresponding line segments, the described line segments will actually refer to the corresponding surfaces, for convenience of description and understanding, in the relevant drawings the respective features will be illustrated in the case where they are presented at the view angle of the drawings, for example the line segments will be presented in the form of points, the surfaces will be presented in the form of line segments, and it will be understood by those skilled in the art that the description of a certain feature in the respective embodiment and the actual construction will differ, since this should be caused by the above-described case.

Referring to fig. 7, the position of the start of the notch 24 on the second tooth portion 22 can be determined by the following formula:

hk＝rk-ra2 (1)，

Where hk is the radial length of the working section relative to the center of rotation (unit: mm), rk is the radius of the circle of the starting point of the notch 24 relative to the center of rotation (unit: mm), ra2 is the radius of the top circle of the second driving wheel 21 (unit: mm), T is the load torque of the second tooth portion 22 (unit: n×mm), ψ is the load non-uniformity coefficient of the second tooth portion 22 (preferably 0.7-0.8), Z is the number of teeth of the second tooth 23, L is the working length of the second tooth 23 in the tooth width direction (unit: mm), and p is the material allowable pressure (unit: MPa).

In this way, it is ensured that the second tooth 23 meets the corresponding load condition requirements.

Specifically, in fig. 7, O is the center of rotation of the first transmission wheel 11 and the second transmission wheel 21. The distance between the point K and the point O may be taken as the radius of a circle R1 passing through the point K with the point O as the center of the circle, or the radius rk of the circle at the start point of the notch 24 with respect to the center of the rotation. ra2 is the radius of the addendum circle R2 formed by the addendum of all the second teeth 23 in the second tooth portion 22. The connection point of the tip of the second tooth 23 and the tooth side of the second tooth 23, or the tip edge point of the second tooth 23, may be denoted as U. The portion of the tooth side of the second tooth 23 from the point U to the point K may be referred to as a working section of the second tooth 23. The radial difference between the circle R1 and the circle R2 can then form the radial length hk of the working segment with respect to the centre of rotation.

Based on the above, the formula (1) defines the radial length of the working section relative to the center of rotation and the position of the K point in mathematical relationship, and the formula (2) defines the radial length of the working section relative to the center of rotation and the position of the K point in physical relationship. Moreover, the equation (2) is a relationship between the radial length of the working segment with respect to the center of rotation and the position where the K point is located, which is obtained on the premise that the structural strength of the second tooth portion 22 is ensured. Since the distances from the point on the tooth side of the second tooth 23 to O are all in one-to-one correspondence, after rk is determined, the position of the K point on the second tooth portion 22 can be determined from the distance from the K point to the O point.

By combining the formula (1) and the formula (2) to obtain the position of the K point, the working section of the second tooth 23 can still have enough structural strength after the notch 24 is arranged, so as to meet the corresponding load working condition requirement. Wherein the load condition demand of the second tooth 23 can be determined by the load torque of the second tooth 22.

The radial length of the working section relative to the rotation center can be in the range of 0.8Mn to 1.2Mn, and Mn is the normal modulus.

Referring to fig. 7, the linear trajectory of the first sidewall segment 25 can be determined by the position of the start of the notch 24 and the pressure angle of the second tooth 23 at the start of the notch 24.

In fig. 7, rb1 is the radius of the base circle R3 of the first tooth portion 12. The N point is located on the base circle R3. The included angle between the line segment KN and the line segment NO is a right angle. The angle between line segment KO and line segment NO is then the pressure angle at the beginning of notch 24.

In particular, after the position of the K point has been determined, the direction of extension of the first sidewall section 25 can then be determined in combination with the pressure angle of the second tooth 23 at the start of the recess 24.

Referring to fig. 7, the second sidewall segment 26 may be an arc segment. The circular arc trajectory of the second sidewall segment 26 may be tangential to the straight trajectory of the first sidewall segment 25, the root circle of the second tooth 22, respectively.

Specifically, in fig. 7, rf2 is the radius of the root circle of the second tooth 23. Referring to fig. 6, in the case of determining the extending direction of the first sidewall section 25 and the circular locus of the root circle of the second tooth 23, an inscribed circle may be made between the first sidewall section 25 and the root circle of the second tooth 23, and the extending locus of the second sidewall section 26 may be determined according to the circular locus of the cavity circle.

The arc length of the second sidewall segment 26 ranges from 0.1Mn to 1Mn, with Mn being the normal modulus.

Specifically, the arc length of the second side wall section 26 is not less than 0.1Mn, and the problem of stress concentration due to the smaller length of the second side wall section 26 can be avoided; the arc length of the second side wall section 26 is not set to 1Mn, and the influence on the strength of the second tooth 23 can be avoided.

In addition, on the basis of the above, the position of the K point and the design ranges of the first side wall section 25 and the second side wall section 26 forming the notch 24 are parameterized, so that the adjustment can be made in accordance with different situations.

A decelerator of an embodiment of the present utility model may include the transmission assembly 100 of any of the embodiments described above.

The speed reducer can be an RV speed reducer. The first driving wheel 11 can be used as a sun wheel for planetary transmission, and the second driving wheel 21 can be used as a driven gear for parallel shaft transmission with the first driving wheel 11. When the speed reducer is driven by the driving assembly 100, the influence on the whole driving effect due to the tooth top interference between the first driving wheel 11 and the second driving wheel 21 can be avoided.

Although embodiments of the present utility model have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to the embodiments of the present utility model without departing from the principles and spirit of the utility model, the scope of which is defined in the appended claims and their equivalents.

Claims (13)

1. A transmission assembly for a decelerator, comprising:

The first driving wheel is circumferentially provided with a first tooth part on the outer circumferential side surface, and the first tooth part is provided with at least one first tooth and;

The inner peripheral side surface of the second driving wheel is provided with a second tooth part in a surrounding mode, the second tooth part is provided with at least one second tooth, and the second tooth is provided with a notch at the tooth root;

The transmission assembly is configured such that the first transmission wheel and the second transmission wheel are engaged and connected through the first tooth portion and the second tooth portion, and such that at least part of the tooth top of the first tooth is located at an opening of a recess of one of the second teeth that is engaged correspondingly.

2. The transmission assembly of claim 1, wherein the first tooth portion is a spline structure.

3. The transmission assembly of claim 2, wherein the first transmission wheel is configured to define a center of rotation of the first transmission wheel by an addendum circle of the first tooth portion, the first tooth portion and the second tooth portion being rotatable about the center of rotation.

4. The transmission assembly of claim 1, wherein a tooth top surface of the first tooth conforms to a tooth bottom surface of the second tooth, a tooth side of the second tooth forming a working section from a tooth top surface edge of the second tooth to a portion of the recess, the second tooth abutting the first tooth through the working section.

5. The transmission assembly of claim 4, wherein the recess opens into a tooth flank of the second tooth.

6. The transmission assembly of claim 4, wherein the recess opens in a portion of the second tooth proximate a root surface of the second tooth;

The side wall of the recess formed by the second tooth part is divided into a first side wall section and a second side wall section, the first side wall section extends from the tooth side of the second tooth to a direction away from the first tooth, and the second side wall section extends from the first side wall section to a direction close to the tooth root surface of the second tooth.

7. The transmission assembly of claim 6, wherein the first sidewall segment is a straight line segment, the direction of extension of the first sidewall segment corresponds to a radial direction of a notch start relative to a center of rotation, the notch start is a connection point between flanks of the first sidewall segment and the second tooth, and the first tooth and the second tooth are rotatable about the center of rotation.

8. The transmission assembly of claim 7, wherein the position of the notch origin on the second tooth portion can be determined by the following formula:

hk＝rk-ra2，

Wherein hk is the radial length of the working section relative to the rotating circle center, rk is the circle radius of the notch starting point relative to the rotating circle center, ra2 is the radius of the addendum circle of the second driving wheel, T is the bearing torque of the second tooth part, ψ is the uneven load coefficient of the second tooth part, Z is the number of teeth of the second tooth, L is the working length of the second tooth in the tooth width direction, and [ p ] is the material allowable pressure.

9. The transmission assembly of claim 8, wherein the radial length of the working segment relative to the center of rotation ranges from 0.8Mn to 1.2Mn with Mn being the normal modulus.

10. The transmission assembly of claim 7, wherein the linear trajectory of the first sidewall segment is determinable by a position at which the notch origin is located, a pressure angle of the second tooth at the notch origin.

11. The transmission assembly of claim 7, wherein the second sidewall segment is a circular arc segment, and wherein the circular arc trajectory of the second sidewall segment is tangent to the linear trajectory of the first sidewall segment and the root circle of the second tooth, respectively.

12. The transmission assembly of claim 11, wherein the arc length of the second sidewall segment has a value in the range of 0.1Mn to 1Mn, mn being the normal modulus.

13. A speed reducer, characterized by comprising:

the transmission assembly of any one of claims 1-12.