CN110645335A - Planetary gear - Google Patents

Abstract

The invention discloses a planetary gear which comprises a gear (1) and a shaft inner hole (2), wherein a plurality of oval pits (201) are fully distributed on the inner wall of the shaft inner hole (2) along the axial direction and the circumferential direction. The planetary gear can ensure good lubrication when the straight shaft is matched for working, effectively slows down the abrasion of the straight shaft and prolongs the service life of a differential assembly.

Description

Planetary gear

Technical Field

The invention belongs to the technical field of a transmission mechanism of a straight bevel gear differential mechanism, and particularly relates to a planetary gear which can ensure good lubrication when a straight shaft is matched for working, effectively slow down the abrasion of the straight shaft and prolong the service life of a differential mechanism assembly.

Background

The differential mechanism of the automobile generally comprises a planetary gear, a straight shaft, a half axle gear, a differential mechanism shell, a spherical gasket, a flat gasket, an elastic pin and the like. The differential housing is connected with the straight shaft to form a planet carrier. When the automobile runs in a straight line on a straight road surface, the planet gear and the half axle gear do not move relatively and keep relatively static; when the automobile is turned, the left and right wheels have rotation speed difference, the planetary gear revolves around the axis of the half shaft and rotates around the axis of the planetary gear, meshing transmission is generated between the planetary gear and the half shaft gear, and meshing teeth are stressed to transmit torque. In the meshing process, due to the influence of the uneven stress of the planetary gear along the circumferential direction, the stressed center line of the planetary gear during rotation and the center line of the linear shaft are not completely overlapped under most conditions, so that the gap between the shaft holes between the planetary gear and the linear shaft is uneven, and the condition of uneven storage of lubricating oil is caused. Under the conditions of sudden load and severe driving conditions, the increase of the load of the differential causes insufficient lubrication between the shaft hole of the planetary gear and the linear shaft, so that the linear shaft is scratched or glued, and finally the linear shaft is broken, and the failure of the whole differential assembly is caused.

Therefore, the prior art has the problems that: because the contact surface clearance is uneven when the planetary gear and the straight shaft work in a matching way, the lubrication condition is poor, the abrasion of the straight shaft is easy to accelerate, and the service life of the whole differential assembly is finally shortened.

Disclosure of Invention

The invention aims to provide a planetary gear which can ensure good lubrication when a straight shaft is matched for working, effectively slow down the abrasion of the straight shaft and prolong the service life of a differential assembly.

The technical scheme for realizing the purpose of the invention is as follows:

a planetary gear comprises a gear 1 and a shaft inner hole 2, wherein a plurality of oval pits 201 are fully distributed on the inner wall of the shaft inner hole 2 along the axial direction and the circumferential direction.

Preferably, the angular interval theta between two circumferentially adjacent oval pits 201 on the inner wall of the shaft inner hole 2 satisfies the following formula,

wherein the content of the first and second substances,

in the formula, n is the circumferential number of the ellipsoid pits on the inner wall of the shaft inner hole, the diameter of the shaft inner hole is D, and b is the short shaft length of the ellipsoid pits.

Compared with the prior art, the invention has the following remarkable advantages:

lubrication is good, effectively slows down a word axle wearing and tearing: the invention combines the surface micro-morphology with the traditional planet gear inner hole to obtain a planet gear inner hole structure with the micro-morphology, which has good lubricating effect when the planet gear rotates and reduces the situation that a linear shaft is scratched and pitting; meanwhile, the micro-morphology inner hole structure can also ensure that the differential mechanism can normally work under the working condition of short-time oil loss under sudden load, so that the danger that the straight shaft is sheared is avoided.

Drawings

Fig. 1 is a schematic view of the structure of a planetary gear of the present invention.

FIG. 2 is a schematic view of a straight shaft and the assembly structure of the planetary gear of the present invention.

Fig. 3 is a sectional view a-a of fig. 2.

Fig. 4 is a partial enlarged view of the inner hole structure of the planetary gear in fig. 3.

Fig. 5 is a sectional view B-B of fig. 3.

Fig. 6 is a cross-sectional view taken along line D-D of fig. 5.

Detailed Description

As shown in figure 1, the planetary gear comprises a gear 1 and a shaft inner hole 2, wherein a plurality of oval pits 201 are fully distributed on the inner wall of the shaft inner hole 2 along the axial direction and the circumferential direction.

Preferably, the angular interval theta between two circumferentially adjacent oval pits 201 on the inner wall of the shaft inner hole 2 satisfies the following formula,

wherein the content of the first and second substances,

in the formula, n is the circumferential number of the ellipsoid pits on the inner wall of the shaft inner hole, the diameter of the shaft inner hole is D, and b is the short shaft length of the ellipsoid pits.

Preferably, the total length of the inner bore of the shaft satisfies the following formula,

L＝2r+(m-1)s+ma，

in the formula, L is the total length of the inner hole of the shaft, r is the distance between the ellipsoid pits and two ends of the shaft hole, m is the axial number of the ellipsoid pits on the inner wall of the inner hole of the shaft, s is the axial distance between the ellipsoid pits, and a is the length of the long shaft of the ellipsoid pit.

The invention is described in detail below with reference to the figures and specific embodiments.

Examples

As shown in fig. 1, a planetary gear, which has good lubrication and effectively slows down the abrasion of a straight shaft, comprises a gear 1 and a shaft inner hole 2, wherein ellipsoidal pits 201 are uniformly distributed on the inner hole structure in a non-complete smooth wall surface structure, the total length of the shaft holes is 27.80mm, the diameter of the shaft holes is 19mm, the ellipsoidal pits are uniformly distributed in the axial direction and the circumferential direction of the inner hole, the axial direction is 23, the circumferential direction is 72, the total number of the ellipsoidal pits is 1656, and the processing method of the ellipsoidal pits adopts a laser shock strengthening method;

FIG. 2 shows an assembly of the planetary gear and the straight shaft;

fig. 3 is a sectional view of the assembly of the planetary gear and the straight shaft along the axis of the straight shaft, fig. 4 is a partial enlarged view of the shaft hole of the gear on the left side in fig. 3, the major axis of the ellipsoid pit is 0.50mm, the minor axis is 0.25mm, the axial distance between the ellipsoid pits is 0.5mm, the distances between the ellipsoid pits and the two ends of the shaft hole are respectively r, r is an uncertain value and changes along with the changes of the total length L of the shaft hole and the diameter D of the shaft hole, and the r is 0.50 mm;

as shown in fig. 5, which is a cross-sectional view of fig. 3 along the axial direction of the horizontal axis, the cross-sectional view of fig. 6 is generated by cutting fig. 5 along the deepest vertex of the oval pit, the circumferential angular interval of the oval pits is 5 degrees, and the circumferential interval is far larger than the short semi-axial length of the oval pit.

The lubricating oil film is always arranged between the axle hole of the planetary gear of the differential gear and the outer diameter of the straight axle, so that the contact lubricating performance is improved, the abrasion between the inner hole of the planetary gear and the straight axle is reduced, and the service life of the whole differential gear assembly is prolonged.

Finally, it should be noted that the above embodiments are only used for illustrating the technical solution of the present invention and not for limiting, all the elements in the negative poisson's ratio structural component in the present invention may adopt the same or different shapes, sizes, cross-sectional shapes, etc., may use the same or different materials, and may be designed with functional parameters according to different use requirements. It will be understood by those skilled in the art that various modifications and equivalent arrangements may be made without departing from the spirit and scope of the present invention and it should be understood that the present invention encompasses the full ambit of the claims appended hereto.

Claims (3)

1. A planetary gear comprising a gear (1) and a shaft bore (2), characterized in that:

a plurality of ellipsoid pits (201) are fully distributed on the inner wall of the shaft inner hole (2) along the axial direction and the circumferential direction.

2. The planetary gear according to claim 1, wherein:

the angular interval theta between two adjacent ellipsoid pits (201) in the circumferential direction of the inner wall of the shaft inner hole (2) satisfies the following formula,

wherein the content of the first and second substances,

in the formula, n is the circumferential number of the ellipsoid pits on the inner wall of the shaft inner hole, the diameter of the shaft inner hole is D, and b is the short shaft length of the ellipsoid pits.

3. The planetary gear according to claim 2, wherein:

the total length of the inner hole of the shaft satisfies the following formula,

L＝2r+(m-1)s+ma，

in the formula, L is the total length of the inner hole of the shaft, r is the distance between the ellipsoid pits and two ends of the shaft hole, m is the axial number of the ellipsoid pits on the inner wall of the inner hole of the shaft, s is the axial distance between the ellipsoid pits, and a is the length of the long shaft of the ellipsoid pit.

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