Electric rear axle differential mechanism, rear axle device and automobile

Abstract

The utility model discloses an electric rear axle differential mechanism which comprises a planetary gear and a gear shaft, and the gear shaft comprises a shaft body and a phosphate coating arranged on the surface of the shaft body. According to the differential mechanism of the electric rear axle, a certain antifriction effect is achieved on the phosphate coating, the abrasion phenomenon of the gear shaft can be improved under the same load, and the working reliability of the differential mechanism is improved. The utility model further discloses a rear axle device and an automobile.

Description

Technical Field

[0001] The utility model belongs to the technical field of automobiles, and specifically relates to an electric rear axle differential, a rear axle device and an automobile. Background Art

[0002] With the rapid development of social economy and logistics, in order to achieve the goal of carbon neutrality, various automobile companies have made rapid efforts in the research and development and manufacturing of new energy electric logistics vehicles, and the market share of electric logistics vehicles has also increased. New energy electric logistics vehicles are playing an increasingly important role in road transportation and people's daily life.

[0003] At present, new energy electric vehicles are facing increasingly higher performance requirements. As the most important load-bearing and transmission component in commercial vehicles, the rear axle needs to meet performance requirements, which affects the driving safety of the vehicle.

[0004] The electric rear axle differential includes planetary gears and gear shafts. The planetary gears are mounted on the gear shafts. The planetary gears and gear shafts are assembled through clearance fit, so that the differential can achieve the differential function. The gear shafts are subjected to extrusion stress during operation, and their failure modes are mainly fracture and wear. Among them, fracture caused by wear and abnormal wear is the main reason, so it is urgent to improve the wear resistance of the gear shaft.

[0005] For example, the patent document with the authorization announcement number CN208348428U discloses a gear shaft and a differential for connecting with the planetary gears of a differential. The gear shaft includes a shaft body with two ends fixed in the differential housing, an oil outlet hole corresponding to the position of the planetary gears is provided on the wall of the shaft body, an oil passage is provided in the shaft body, the oil outlet hole is connected to the oil passage, and oil inlets are provided at both ends of the oil passage, which are connected to the outside of the differential housing. The technical solution disclosed in the patent document also cannot solve the technical problems described above. Utility Model Content

[0006] The utility model aims to solve at least one of the technical problems existing in the prior art. To this end, the utility model provides an electric rear axle differential, the purpose of which is to improve reliability.

[0007] In order to solve the above technical problems, the technical solution adopted by the utility model is: an electric rear axle differential includes a planetary gear and a gear shaft, and the gear shaft includes a shaft body and a phosphating layer arranged on the surface of the shaft body.

[0008] The planetary gear comprises a gear body and a boss arranged on the gear body, and the gear shaft passes through the boss and the gear body.

[0009] The boss is a cylinder, and the boss and the gear body are coaxially arranged.

[0010] The outer diameter of the boss is smaller than the outer diameter of the gear body.

[0011] The thickness of the boss is 4 mm.

[0012] The utility model also provides a rear axle device, comprising the electric rear axle differential.

[0013] The utility model also provides a car, comprising the rear axle device.

[0014] The electric rear axle differential of the utility model performs phosphating treatment on the gear shaft, and the formed phosphating layer has a certain friction reduction effect, which can improve the wear phenomenon of the gear shaft under the same load and improve the working reliability of the differential. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a structural schematic diagram of the electric rear axle differential of the utility model;

[0016] Figure 2 It is a schematic diagram of the structure of a planetary gear;

[0017] The markings in the above figures are: 1. differential case; 2. planetary gear; 3. gear body; 4. boss; 5. gear shaft. DETAILED DESCRIPTION

[0018] The specific implementation methods of the utility model are further explained in detail below with reference to the accompanying drawings through the description of embodiments, with the aim of helping technicians in the field to have a more complete, accurate and in-depth understanding of the concept and technical solution of the utility model and facilitating its implementation.

[0019] It should be noted that when an element is referred to as being "fixed on" another element, it may be directly on the other element or there may be a central element. When an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be a central element at the same time. The terms "vertical", "horizontal", "upper", "lower" and similar expressions used in this article are for illustrative purposes only.

[0020] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly connected by technicians in the technical field to which the present invention belongs. The terminology used in the specification of the present invention is for the purpose of describing specific embodiments and is not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more related listed items.

[0021] like Figure 1As shown, the utility model provides an electric rear axle differential, including a differential housing 1, a planetary gear 2 and a gear shaft 5, wherein the planetary gear 2 is mounted on the gear shaft 5, and the gear shaft 5 includes a shaft body and a phosphating layer arranged on the outer surface of the shaft body. By phosphating the gear shaft 5, the phosphating layer formed has a certain friction reduction effect, which can improve the wear phenomenon of the gear shaft 5 under the same load and improve the working reliability of the differential.

[0022] like Figure 1 and Figure 2 As shown, the planetary gear 2 includes a gear body 3 and a boss 4 disposed on the gear body 3, the boss 4 is fixedly connected to one end of the gear body 3, and the gear shaft 5 passes through the boss 4 and the center hole of the gear body 3. The boss 4 is a cylinder, and the boss 4 and the gear body 3 are coaxially arranged. Two planetary gears 2 are installed on the gear shaft 5, and the bosses 4 of the two planetary gears 2 are arranged oppositely, and the outer diameter of the boss 4 is smaller than the outer diameter of the gear body 3.

[0023] Preferably, the thickness of the boss 4 is 4 mm, and the thickness direction of the boss 4 is also the axial direction thereof. The diameter of the gear shaft is 17 mm.

[0024] In this embodiment, the size of the planetary gear 2 is φ17F8 (+0.043 / +0.016), and the size of the gear shaft 5 is φ17e7 (-0.032 / -0.050). A boss 4 with a thickness of 4 mm is added to the planetary gear 2 to increase the contact length with the gear shaft 5, thereby reducing the contact stress between the two under the same load and slowing down / improving the wear phenomenon. The data is as follows:

[0025] Maximum engine output torque (Nm) 142 Transmission 1st gear ratio 3.83 Final reduction ratio 4.778 Gear shaft 5 diameter φ17 Distance from the midpoint of the planetary gear 2 support surface to the cone top l (mm) 30.78 Support surface length (mm) 21.88 Extrusion strength of the support surface after increasing the contact length (MPa) 113.48 20CrMnTi tensile strength (MPa) ≥1100 20CrMnTi yield strength (MPa) ≥850 20CrMnTi allowable extrusion strength (MPa) 210 Original support surface length (mm) 17.88 Original state extrusion strength (MPa) 138.87 Compare status -25.39 trend ↓

[0026] Finally, due to the poor lubrication caused by the small clearance between the gear shaft 5 and the planetary gear 2, the planetary gear 2 and the gear shaft 5 frequently suffer from wear, bonding, and fracture. The abnormal wear problem can also be improved by adjusting the clearance tolerance between the planetary gear 2 and the shaft pin. At the same time, the dimension verification and related bench tests should be added here in the subsequent engineering design to design a reasonable dimension match.

[0027] The utility model also provides a rear axle device, including the electric rear axle differential of the above structure. The specific structure of the electric rear axle differential can be referred to Figure 1 to Figure 2 Since the rear axle device of the utility model includes the electric rear axle differential in the above embodiment, it has all the advantages of the above electric rear axle differential.

[0028] The utility model also provides a car, comprising the rear axle device of the structure.

[0029] The utility model is described above by way of example in conjunction with the accompanying drawings. It is obvious that the specific implementation of the utility model is not limited to the above-mentioned method. As long as various non-substantial improvements are made using the method concept and technical solution of the utility model, or the concept and technical solution of the utility model are directly applied to other occasions without improvement, they are all within the protection scope of the utility model.

Claims

1. An electric rear axle differential, comprising a planetary gear and a gear shaft, characterized in that: The gear shaft comprises a shaft body and a phosphating layer arranged on the surface of the shaft body; The planetary gear comprises a gear body and a boss arranged on the gear body, the boss is fixedly connected to one end of the gear body, and the gear shaft passes through the boss and the center hole of the gear body; the boss is a cylinder, the boss and the gear body are coaxially arranged, two planetary gears are installed on the gear shaft, the bosses of the two planetary gears are arranged oppositely, and the outer diameter of the boss is smaller than the outer diameter of the gear body; The thickness of the boss is 4 mm, the thickness direction of the boss is also its axial direction, and the diameter of the gear shaft is 17 mm.

2. A rear axle device, characterized in that: It includes the electric rear axle differential as claimed in claim 1.

3. Automobile, characterized in that: Includes the rear axle device as described in claim 2.

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