A modified spiral bevel gear for use with automotive differentials

Abstract

This utility model relates to the field of differential technology, and more particularly to a modified spiral bevel gear for automotive differentials. The technical solution includes: a planetary gear, a half-shaft gear, and a planetary gear shaft. The planetary gear is mounted on the planetary gear shaft and meshes with the half-shaft gear. These three components constitute the core components for power transmission in the differential. Both the planetary gear and the half-shaft gear are spiral bevel gears. The spiral teeth are modified with a zero-degree helix angle, a pressure angle of 22.5°–27°, and a tooth tip height coefficient of 0.7–0.9. The zero-degree helix angle reduces axial force loss in the transmission, improving power transmission efficiency and fuel economy. The large pressure angle and short tooth profile synergistically optimize meshing performance, ensuring uniform power distribution and vehicle stability during straight-line driving. The planetary gear shaft is made of medium-carbon alloy steel with heat treatment and a lubrication design, combined with precision forging technology, extending component life and reducing production costs.

Description

Technical Field

[0001] This utility model relates to the field of differential technology, specifically a modified spiral bevel gear for use with automotive differentials. Background Technology

[0002] The automotive differential is a key component enabling differential rotation between the left and right wheels. Its core transmission component is a spiral bevel gear pair, which directly affects the vehicle's power transmission efficiency, driving stability, and component lifespan. Traditional spiral bevel gears often employ a non-zero helix angle, a 20° standard pressure angle, and a 1.0 standard addendum coefficient, which presents the following problems in practical applications:

[0003] Traditional spiral bevel gears have a large helix angle, resulting in significant axial force during transmission. This causes components such as the differential housing and bearings to bear additional axial loads, while also increasing frictional losses on the gear meshing surfaces. This leads to excessive energy loss during power transmission, reducing vehicle power response speed and fuel economy. When driving straight, if the gear pressure angle is small, the tooth surface contact area is limited, and uneven force is easily generated under load, leading to gear wobble or vibration, affecting the uniformity of power distribution, and potentially causing vehicle deviation, body sway, and other phenomena.

[0004] Meanwhile, the standard tooth tip height coefficient can easily lead to a sharper tooth tip when the number of gear teeth is small, which aggravates tooth surface wear and further weakens driving stability. Traditional gear processing technology relies heavily on cutting, resulting in poor tooth profile accuracy and surface quality, and the tooth root is prone to fracture due to stress concentration. If the lubrication design of the planetary gear shaft is unreasonable or the material strength is insufficient, it will aggravate the friction and wear of the mating surface with the planetary gear, shortening the service life of the entire gear pair and related differential components. In view of this, we propose a modified spiral bevel gear for automobile differentials to solve the existing problems. Utility Model Content

[0005] The purpose of this invention is to provide a modified spiral bevel gear for use with automotive differentials, in order to solve the problems mentioned in the background art.

[0006] To achieve the above objectives, this utility model provides the following technical solution: a modified spiral bevel gear for a matching automobile differential, comprising planetary gears, half-shaft gears, and planetary gear shafts. Each planetary gear shaft is provided with a planetary gear, and each planetary gear is meshed with a half-shaft gear. Both the planetary gears and the half-shaft gears are spiral bevel gears, and the spiral teeth of both are uniformly modified according to a helix angle of 0°, a pressure angle of 22.5° to 27°, and a tooth tip height coefficient of 0.7 to 0.9.

[0007] Preferably, the arc teeth of the planetary gears and half-shaft gears are designed with a zero-degree helix angle. The diameter of the cutting tool is adjusted according to different tooth profiles to ensure that the forging can be directly demolded, while minimizing the axial force on the gear pair during operation.

[0008] Preferably, the arc teeth of the planetary gears and half-shaft gears are designed with a pressure angle of 22.5° to 27° to reduce the risk of tooth undercut and ensure that the forgings can be directly demolded.

[0009] Preferably, the planetary gears and half-shaft gears are designed with short teeth with a tooth tip height coefficient of 0.7 to 0.9 to avoid the tooth tip becoming sharp due to the small number of teeth on the differential gears.

[0010] Preferably, the planetary gears and half-shaft gears are precision forged, which makes them easy to demold during precision forging.

[0011] Preferably, the planetary gear shaft is a cross shaft, made of medium carbon alloy steel, heat-treated, and the journal surface is ground.

[0012] Compared with the prior art, the beneficial effects of this utility model are:

[0013] 1. In the transmission path of engine power through the differential housing, planetary gear shaft, planetary gears to half-shaft gears, the planetary gears and half-shaft gears adopt a zero-degree helix angle design, which greatly reduces the axial force loss in the transmission process. Compared with traditional non-corrected spiral bevel gears, the reduction of axial force reduces the energy loss caused by friction and component deformation during power transmission, ensuring that more power can be effectively transmitted to the wheels, improving vehicle power response speed and fuel economy.

[0014] 2. When driving in a straight line, the planetary gears only revolve around the sun and do not rotate on their own axis. The resistance on the left and right half-shaft gears is balanced, and the forces on both sides of the planetary gears are balanced. This stable meshing state, combined with the gears' large pressure angle design of 22.5° to 27°, makes the tooth surface contact area larger and the load distribution more uniform, avoiding gear wobble or vibration caused by uneven force. At the same time, the short tooth system with a tooth tip height coefficient of 0.7 to 0.9 enhances the tooth tip strength, reduces tooth surface wear, ensures the uniformity of power distribution when driving in a straight line, makes the vehicle drive smoothly, and reduces deviation or body swaying.

[0015] 3. The planetary gear shaft is made of medium carbon alloy steel with heat treatment, which reduces friction and wear between the planetary gear and the journal, and improves the durability of the shaft. In addition, the precision forging process of the gear ensures the tooth profile accuracy and surface quality. The synergistic design of zero helix angle, large pressure angle and short tooth system reduces the stress concentration at the tooth root, making the planetary gear and half shaft gear less prone to failures such as tooth root fracture and tooth tip chipping during long-term power transmission, which significantly extends the service life of the entire gear pair and related differential parts.

[0016] 4. The structural design of the gear in the power transmission path, with a zero-degree helix angle and a large pressure angle, ensures that the forging can be directly demolded, reducing subsequent machining processes. Precision forging not only improves the dimensional accuracy of the gear, but also avoids material waste caused by cutting in traditional machining, reducing production energy consumption and labor costs. At the same time, the forging process enhances the density of the gear metal. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the overall structure of this utility model;

[0018] Figure 2 This is a schematic diagram of the meshing of the planetary gear and the half-shaft gear in this utility model;

[0019] Figure 3 This is a schematic diagram of the half-shaft gear in this utility model;

[0020] Figure 4 This is a schematic diagram of the planetary gear in this utility model.

[0021] In the diagram: 1. Planetary gear; 2. Half-shaft gear; 3. Planetary gear shaft. Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of this utility model clearer, the present utility model will be further described in detail below with reference to specific embodiments and accompanying drawings. It should be understood that these descriptions are merely exemplary and not intended to limit the scope of this utility model. Furthermore, descriptions of well-known structures and technologies are omitted in the following description to avoid unnecessarily obscuring the concept of this utility model.

[0023] like Figures 1-4 As shown, the present invention proposes a modified spiral bevel gear for a matching automobile differential, comprising a planetary gear 1, a half-shaft gear 2, and a planetary gear shaft 3. Each planetary gear shaft 3 is provided with a planetary gear 1, and each planetary gear 1 is meshed with a half-shaft gear 2. Both the planetary gear 1 and the half-shaft gear 2 are spiral bevel gears, and the spiral teeth of both are uniformly modified according to a helix angle of 0°, a pressure angle of 22.5° to 27°, and a tooth tip height coefficient of 0.7 to 0.9.

[0024] In an optional embodiment, the arc teeth of the planetary gear 1 and the half-shaft gear 2 are uniformly designed with a zero-degree helix angle. The size of the cutting tool diameter is adjusted according to different tooth profiles to ensure that the forging can be directly demolded, while minimizing the axial force on the gear pair during operation.

[0025] In an optional embodiment, the arc teeth of the planetary gear 1 and the half-shaft gear 2 are uniformly designed with a pressure angle of 22.5° to 27° to reduce the risk of tooth undercut and ensure that the forging can be directly demolded.

[0026] In an optional embodiment, the arc teeth of the planetary gear 1 and the half-shaft gear 2 are uniformly designed with a short tooth system with a tooth tip height coefficient of 0.7 to 0.9 to avoid the tooth tip becoming sharp due to the small number of teeth of the differential gear.

[0027] In an optional embodiment, the planetary gear 1 and the half-shaft gear 2 are precision forged, which makes them easy to demold during precision forging.

[0028] In an optional embodiment, the planetary gear shaft 3 is a cross shaft made of medium carbon alloy steel, which is heat-treated and the journal surface is ground.

[0029] The working principle of this utility model is as follows: When the engine power is transmitted to the differential housing, the differential housing drives the planetary gear shaft 3 to rotate synchronously. Since the planetary gear 1 is installed on the journal of the planetary gear shaft 3, the rotation of the planetary gear shaft 3 will drive the planetary gear 1 to revolve. At this time, the half-shaft gear 2 that meshes with the planetary gear 1 will rotate under the meshing force, thereby transmitting the power to the left and right wheels through the half-shaft, so as to realize the normal driving of the vehicle.

[0030] When driving in a straight line, the resistance experienced by the left and right wheels is basically the same. At this time, planetary gear 1 only revolves around half-shaft gear 2 and does not rotate on its own. This is because the resistance experienced by the left and right half-shaft gears 2 is the same, and the forces experienced by both sides of planetary gear 1 are balanced, so that planetary gear 1 and half-shaft gear 2 maintain stable meshing transmission, and the power can be evenly distributed to the left and right wheels to ensure the stability of the vehicle driving in a straight line.

[0031] When the vehicle turns, the inner wheel travels a shorter path and experiences greater resistance, while the outer wheel travels a longer path and experiences relatively less resistance. At this time, the rotational speeds of the left and right half-shaft gears 2 differ. While revolving around the planetary gear, the planetary gear 1 begins to rotate around the journal of the planetary gear shaft 3. Through the rotation of the planetary gear 1, the rotational speeds of the left and right half-shaft gears 2 can be adjusted, causing the inner wheel to rotate slower and the outer wheel to rotate faster, thereby achieving differential rotation of the two wheels and ensuring that the vehicle turns smoothly.

[0032] In this process, the spiral teeth of planetary gear 1 and half-shaft gear 2 adopt a zero-helix angle (0°) design, which effectively reduces the axial force during gear pair operation, lowers the axial load on planetary gear shaft 3, differential housing, and related bearings, and ensures transmission stability. The pressure angle is designed to be 22.5°~27°, reducing the risk of tooth undercut, enhancing the structural strength of the gears, and facilitating forging demolding. The tooth tip height coefficient adopts a short tooth design of 0.7~0.9, avoiding the tooth tip sharpening phenomenon caused by the small number of teeth in the differential gears, and improving the service life of the gears. In addition, planetary gear 1 and half-shaft gear 2 are precision forged, ensuring the precision and quality of the gears, and the precision forging process facilitates demolding, improving production efficiency. Planetary gear shaft 3 is a cross shaft, made of medium carbon alloy steel and heat-treated. The journal surface is ground, possessing good strength and wear resistance. The oil grooves or oil holes on the journal can guide gear oil into the mating surface, playing a lubricating role, reducing friction and wear between planetary gear 1 and the journal, and ensuring the efficient and stable operation of the entire gear system.

[0033] It should be understood that the specific embodiments described above are for illustrative purposes or to explain the principles of this utility model, and do not constitute a limitation thereof. Therefore, any modifications, equivalent substitutions, improvements, etc., made without departing from the spirit and scope of this utility model should be included within its protection scope. Furthermore, the appended claims are intended to cover all variations and modifications falling within the scope and boundaries of the appended claims, or equivalent forms of such scope and boundaries.

Claims

1. A modified spiral bevel gear for use with automotive differentials, characterized in that: It includes planetary gears (1), half-shaft gears (2) and planetary gear shafts (3). Each planetary gear shaft (3) is provided with a planetary gear (1). Each planetary gear (1) is meshed with a half-shaft gear (2). Both planetary gears (1) and half-shaft gears (2) are spiral bevel gears. The spiral teeth of both are uniformly designed with a helix angle of 0°, a pressure angle of 22.5° to 27° and a tooth tip height coefficient of 0.7 to 0.

9.

2. A modified arcuate splined bevel gear for a complete automotive differential as set forth in claim 1, characterized in that: The planetary gear (1) and the half-shaft gear (2) are designed with a zero-degree helix angle. The diameter of the cutting tool is adjusted according to different tooth structures to ensure that the forging can be directly demolded, while minimizing the axial force on the gear pair during operation.

3. A modified arcuate splined bevel gear for a complete automotive differential as set forth in claim 1, characterized in that: The arc teeth of the planetary gear (1) and the half-shaft gear (2) are designed with a pressure angle of 22.5° to 27° to reduce the risk of tooth undercut and ensure that the forging can be directly demolded.

4. The modified arcuate splined bevel gear for a complete automotive differential of claim 1 wherein: The planetary gear (1) and the half-shaft gear (2) are designed with short teeth with a tooth tip height coefficient of 0.7 to 0.9 to avoid the tooth tip becoming sharp due to the small number of teeth on the differential gear.

5. A modified arcuate splined bevel gear for a complete automotive differential as defined in claim 1 wherein: The planetary gear (1) and the half-shaft gear (2) are precision forged, and are easy to demold during precision forging.

6. A modified arcuate splined bevel gear for a complete automotive differential as defined in claim 1 wherein: The planetary gear shaft (3) is a cross shaft, made of medium carbon alloy steel, and is heat-treated and the journal surface is ground.

Images