Balance shaft structure

Abstract

A balance shaft structure belongs to the technical field of automobile engines. The integrated balance shaft structure is adopted, torque is transmitted without relying on a matching surface, interference press fitting is not needed between the shaft and the teeth, gear failure is avoided, and transmission motion is reliable; the shaft and the teeth are integrated into one part, so that gear and shaft diameter machining surfaces are reduced, and the cost is reduced; the balance shaft is made of low-carbon steel, shaft teeth are integrally formed in a precision forging mode, the heat treatment performance is good, carburizing and quenching can be conducted, the gear strength and the balance shaft rigidity are improved, and the problem that the hardness of a bearing matching face is insufficient due to the fact that the structure is compact and high-frequency quenching cannot be achieved is solved. The shaft and the teeth are integrated into one part, the strength and the reliability are enhanced, under the same working condition, the occupied space is smaller, and the integrated structure is firmer. The balance shaft and the shell are supported through the bearing bush, press fitting is not needed, assembling is easy, the bearing is light in weight and small in size, cost can be reduced, and the occupied space of the structure is reduced.

Description

Technical Field

[0001] The utility model belongs to the technical field of automobile engines, and in particular relates to a balance shaft structure. Background Art

[0002] Balance shaft technology is a widely used and very practical engine technology. It can effectively reduce vehicle vibration, improve driving comfort, and ensure stable and smooth engine operation. Its working principle is to design and arrange unbalanced weights on the balance shaft according to the simulation analysis results of the unbalanced amount of the crankshaft operation. When the crankshaft is running, the balance shaft runs in the opposite direction to offset the unbalanced amount generated by the crankshaft and eliminate vibration.

[0003] The existing balance shaft structure mostly adopts a split balance shaft structure (attached Figure 2 ), the heating process flow of the balance shaft and gear of this structure is relatively simple, and the manufacturing difficulty is relatively small, but the torque is transmitted between the balance shaft and the gear by interference fit, and the press-fitting process is adopted, and the process is complicated; the interference fit has high requirements on the processing accuracy of the inner hole and shaft diameter of the gear, and the clamping function cost is high, and when the interference is insufficient, the gear transmission failure problem is prone to occur; in order to ensure the strength and reliability of the parts and avoid plastic deformation after press-fitting, the balance shaft shaft diameter and gear wall thickness need to be simulated and calculated separately, and the structure occupies a large space; the structural strength is poor, and when the interference is insufficient, the gear transmission failure is prone to occur. The material of split balance shaft is mostly ductile iron (QT600, QT700). Due to the hard iron matrix of ductile iron, it is difficult to form structure during heat treatment, and it is easy to produce thermal cracks, and the overall rigidity is poor. Therefore, the bearing mating surface is mostly subjected to local heat treatment by high-frequency quenching to improve hardness and wear resistance, but the tolerance range of high-frequency quenching is increased, which cannot be achieved when the balance shaft structure is compact, which may cause insufficient hardness of the balance shaft bearing mating shaft diameter; bearings are used between the balance shaft and the housing for support, and the bearings and the balance shaft have an interference fit, which requires press-fitting, complicated assembly, large bearing size, high mass, and high cost. Utility Model Content

[0004] The utility model provides a balancing shaft structure to solve the problems of complicated assembly process of existing balancing shafts, high machining cost, gear transmission failure, poor balancing shaft stiffness, poor heat treatment performance, insufficient hardness of bearing mating surface caused by inability to achieve high-frequency quenching when the structure is compact, and the use of bearing supports, high quality, large space occupation, high cost and complex assembly.

[0005] The technical solution adopted by the utility model is:

[0006] A balancing shaft structure comprises a driving shaft assembly and a driven shaft assembly; the driving shaft assembly comprises a driving shaft, scissor teeth, a wave spring, a clamping ring, a gasket, a driving gear and a driving bearing; the front end of the driving shaft is integrally connected with the driving gear, the scissor teeth are sleeved on the driving shaft at the front end of the driving gear, the clamping ring is clamped on the driving shaft at the front end of the scissor teeth, the clamping ring fixes the scissor teeth on the driving shaft through the gasket, a wave spring is arranged between the gasket and the scissor teeth, and two driving bearings are installed on the shaft body of the driving shaft.

[0007] Compared with the prior art, the utility model has the following beneficial effects:

[0008] The utility model adopts an integrated balance shaft structure, which does not need to rely on the matching surface to transmit torque, and does not need interference press-fitting between the shaft and the gear, so as to avoid gear failure and transmit motion reliably; the shaft and the gear are integrated into one part, which reduces the gear and shaft diameter machining surface and reduces costs; the press-fitting process is omitted, and the assembly is simple. The balance shaft material is low-carbon steel, and the shaft and the gear are integrally forged, which has good heat treatment performance and can be carburized and quenched. The gear strength and the balance shaft rigidity are improved, and the problem of insufficient hardness of the bearing matching surface caused by the compact structure and the inability to achieve high-frequency quenching is avoided. The shaft and the gear are integrated into one part, and the strength and reliability are enhanced. Under the same working conditions, the space occupied is smaller and the integrated structure is more solid. The balance shaft and the housing are supported by bearing shells, which do not need to be pressed, and the assembly is simple. The bearing is light in weight and small in size, which can reduce costs and reduce the space occupied by the structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 It is a schematic diagram of the structure of the existing balancing shaft driving shaft;

[0010] Figure 2 It is a schematic diagram of the structure of the existing balancing shaft driven shaft;

[0011] Figure 3 This is a schematic diagram of the structure of the driving shaft assembly of the utility model;

[0012] Figure 4 This is a schematic diagram of the structure of the driven shaft assembly of the utility model;

[0013] Among them: 1. driving shaft; 2. pin; 3. scissor teeth; 4. wave spring; 5. retaining ring; 6. gasket; 7. driving gear; 8. driving bearing; 9. driven shaft; 10. driven gear; 11. driven bearing; 12. existing scissor teeth main teeth; 13. existing split balance shaft; 14. existing pin; 15. existing scissor teeth auxiliary teeth; 16. existing wave spring; 17. existing retaining ring; 18. existing gasket; 19. existing bearing one; 20. existing bearing two; 21. existing balance shaft driven gear; 22. existing split balance shaft. DETAILED DESCRIPTION

[0014] In order to better understand the purpose, structure and function of the present invention, the present invention is further described in detail below in conjunction with the accompanying drawings.

[0015] like Figure 1 , Figure 2 The figure shows a schematic diagram of the existing balance shaft structure, wherein 12 is the existing scissor-tooth main tooth; 13 is the existing split balance shaft; 14 is the existing pin; 15 is the existing scissor-tooth auxiliary tooth; 16 is the existing wave spring; 17 is the existing retaining ring; 18 is the existing gasket; 19 is the existing bearing one; 20 is the existing bearing two; 21 is the existing balance shaft driven gear; and 22 is the existing split balance shaft.

[0016] The existing balance shaft structure is a split type.

[0017] like Figure 3 , Figure 4 As shown, the utility model provides a balancing shaft structure, including a driving shaft assembly and a driven shaft assembly; the driving shaft assembly includes a driving shaft 1, scissor teeth 3, a wave spring 4, a clamping ring 5, a gasket 6, a driving gear 7 and a driving bearing 8; the front end of the driving shaft 1 is integrally connected with the driving gear 7, the scissor teeth 3 are sleeved on the driving shaft 1 at the front end of the driving gear 7, the clamping ring 5 is clamped on the driving shaft 1 at the front end of the scissor teeth 3, the clamping ring 5 fixes the scissor teeth 3 on the driving shaft 1 through the gasket 6, a wave spring 4 is arranged between the gasket 6 and the scissor teeth 3, and two driving bearings 8 are installed on the shaft body of the driving shaft 1.

[0018] The scissor teeth 3 and the driving gear 7 are limited by a pin 2.

[0019] like Figure 4 As shown, the driven shaft assembly includes a driven shaft 9, a driven gear 10 and two driven bearing shells 11; the front end of the driven shaft 9 is integrally connected with the driven gear 10, and two driven bearing shells 11 are installed on the shaft body of the driven shaft 9.

[0020] The driving shaft 1 and the driving gear 7 are made of low carbon steel (20CrMnTiH) and are integrally forged.

[0021] The driven shaft 9 and the driven gear 10 are made of low carbon steel (20CrMnTiH) and are integrally precision forged.

[0022] It is understood that the present invention is described by some embodiments, and those skilled in the art are aware that various changes or equivalent substitutions may be made to these features and embodiments without departing from the spirit and scope of the present invention. In addition, under the teachings of the present invention, these features and embodiments may be modified to adapt to specific circumstances and materials without departing from the spirit and scope of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed herein, and all embodiments falling within the scope of the claims of this application are within the scope of protection of the present invention.

Claims

1. A balance shaft structure, characterized in that: The invention comprises a driving shaft assembly and a driven shaft assembly; the driving shaft assembly comprises a driving shaft (1), a scissor tooth (3), a wave spring (4), a clamping ring (5), a gasket (6), a driving gear (7) and a driving bearing (8); the front end of the driving shaft (1) is integrally connected with the driving gear (7); the scissor tooth (3) is sleeved on the driving shaft (1) at the front end of the driving gear (7); the clamping ring (5) is clamped on the driving shaft (1) at the front end of the scissor tooth (3); the clamping ring (5) fixes the scissor tooth (3) on the driving shaft (1) through the gasket (6); a wave spring (4) is arranged between the gasket (6) and the scissor tooth (3); and two driving bearings (8) are installed on the shaft body of the driving shaft (1).

2. A balancing shaft structure according to claim 1, characterized in that: The scissor teeth (3) and the driving gear (7) are limited by a pin (2).

3. A balancing shaft structure according to claim 1 or 2, characterized in that: The driven shaft assembly comprises a driven shaft (9), a driven gear (10) and two driven bearing shells (11); the front end of the driven shaft (9) is integrally connected to the driven gear (10), and the two driven bearing shells (11) are installed on the shaft body of the driven shaft (9).

4. A balancing shaft structure according to claim 3, characterized in that: The driving shaft (1) and the driving gear (7) are made of low carbon steel and are integrally formed by precision forging; the driven shaft (9) and the driven gear (10) are made of low carbon steel and are integrally formed by precision forging.

5. A balancing shaft structure according to claim 4, characterized in that: The low carbon steel used in the driving shaft assembly and the driven shaft assembly is 20CrMnTiH.

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