An engine balance shaft gear set with buffer function

Abstract

The engine balance shaft gear set with buffering function of the present invention comprises a driving gear, a driven gear and a buffer gear, wherein the buffer gear is made of spring steel, and the number of teeth and module of the buffer gear and the driven gear are the same, and the buffer gear comprises a circular mounting portion, an elastic arm and a buffer gear body, and the center of the mounting circular hole in the middle of the circular mounting portion is offset from the center of the indexing circle of the buffer gear, and the buffer gear is mounted at one end of the balance shaft and rests on the surface of one end of the driven gear, and the teeth of the buffer gear and the teeth of the driven gear are mutually misaligned, and in the process of meshing of the driven gear and the driving gear, each tooth of the driving gear first contacts with the teeth of the buffer gear and then contacts with the teeth of the driven gear. The present invention can effectively eliminate the impact force during gear transmission, and finally eliminate the transmission noise of the balance shaft gear, and improve the reliability of the balance shaft gear pair.

Description

Technical Field

[0001] The invention relates to the technical field of engines, and in particular to a balance shaft gear set of an engine. Background Art

[0002] When developing a small, efficient three-cylinder engine, in order to eliminate the unbalanced torque when the three-cylinder engine is working, a balance shaft is usually arranged on the engine. A balance shaft gear (driven gear) is installed on the balance shaft. The rotation direction of the balance shaft is opposite to the rotation direction of the crankshaft to balance the unbalanced torque of the three-cylinder engine. The driving balance shaft usually adopts gear transmission, and the driven gear on the balance shaft is driven by the driving gear on the crankshaft.

[0003] When the engine is working, the driving gear on the crankshaft drives the driven gear on the balance shaft. Because automotive engines have high requirements on engine noise and vibration, it is necessary to eliminate impact and impact noise as much as possible by optimizing the structure during the design process.

[0004] Figure 1 The figure shows the driving gear pair of the engine balance shaft. The driving gear 1' is installed on the crankshaft, and the driven gear 2' is installed on the balance shaft. The gear pair has high requirements for installation accuracy and processing requirements for the gear center distance, which will result in high manufacturing costs. If the processing and installation accuracy do not meet the requirements, the impact noise of the gear transmission will be obvious, especially when the engine is running at a high speed and when there is a sudden change in the working conditions, such as rapid acceleration and deceleration. If the accuracy is low, the impact force and noise of the gear pair transmission will be particularly obvious. At the same time, as a key component of the engine, the balance shaft gear pair transmission needs to meet reliability requirements. If the gear pair is subjected to long-term impact, there will be a risk of wear and failure, which will eventually affect the life of the engine. Summary of the invention

[0005] The purpose of the present invention is to provide an engine balance shaft gear set with a buffering function in view of the defects of the above-mentioned prior art, which can effectively eliminate the impact force during gear transmission, ultimately eliminate the transmission noise of the balance shaft gear, and improve the reliability of the balance shaft gear pair.

[0006] The technical solution adopted by the present invention to achieve the above-mentioned purpose is: an engine balance shaft gear set with a buffer function, including a driving gear and a driven gear, the driving gear is installed on the driving shaft of the engine through the center hole of the driving gear, the driven gear is installed on the balance shaft of the engine through the center hole of the driven gear, and a circular arc guide step is protruding on the surface of one end of the driven gear, and also includes a buffer gear, the buffer gear is an elastic gear made of spring steel, the number of teeth and the module of the buffer gear are respectively the same as the number of teeth and the module of the driven gear, the thickness of the buffer gear is less than the thickness of the driven gear, the buffer gear includes a circular ring mounting portion, an elastic arm and a buffer gear body, the circular ring mounting portion is located in the inner middle of the buffer gear, the elastic arm is formed by extending from the outer edge of the circular ring mounting portion, the outer end of the elastic arm is connected to the buffer gear body, and the elastic arm is connected to the buffer gear body An arc-shaped guide groove is formed therebetween, a mounting circular hole is provided in the middle of the annular mounting portion, the center of the mounting circular hole is offset from the center of the dividing circle of the buffer gear, a fixing bolt passes through the mounting circular hole of the buffer gear to mount the buffer gear on one end face of the balance shaft, and the buffer gear leans against one end surface of the driven gear, an arc guide step of the driven gear passes through the arc-shaped guide groove of the buffer gear, when the buffer gear leans against one end surface of the driven gear, the teeth of the buffer gear and the teeth of the driven gear are misaligned with each other, and the misalignment is slightly larger than the meshing clearance of the gear pair in which the driving gear and the driven gear are meshed, and during the meshing process of the driven gear and the driving gear, the teeth of the driving gear first contact with the teeth of the buffer gear and then contact with the teeth of the driven gear.

[0007] A further technical solution of the present invention is that the center of the installation circular hole of the buffer gear is offset from the center of the dividing circle of the buffer gear by 0.5-2 mm.

[0008] A further technical solution of the present invention is: the elastic arm of the buffer gear includes an elastic arm I vertically connected to the outer edge of the circular ring mounting portion and an elastic arm II extending from one side of the elastic arm I to form an arc shape, the arc guide groove is between the elastic arm II and the buffer gear body, the position of the arc guide groove corresponds to the position of the arc guide step of the driven gear, and a gap is provided between the side wall of the arc guide groove and the outer surface of the arc guide step.

[0009] A further technical solution of the present invention is: an installation adjustment pin hole is provided on one side of the arc guide step of the driven gear, and the eccentric pin passes through the arc guide groove of the buffer gear and enters the installation adjustment pin hole. The tooth misalignment amount between the buffer gear and the driven gear can be adjusted by rotating the eccentric pin.

[0010] A further technical solution of the present invention is that the end surface of the driven gear is also provided with a positioning hole for positioning when connected to the balance shaft.

[0011] A further technical solution of the present invention is that: the driven gear is also provided with a dynamic balancing weight-reducing hole for reducing the weight of the gear.

[0012] The engine balance shaft gear set with a buffering function of the present invention has the following beneficial effects: the engine balance shaft gear set with a buffering function of the present invention is composed of a driving gear and a driven gear, and a buffering gear is arranged on the driven gear. Through the misalignment of the teeth of the buffering gear and the driven gear, when the driving gear and the driven gear are meshed with each other, the driving gear first contacts and meshes with the buffering gear, and then contacts and meshes with the driven gear after buffering to drive the balance shaft, which can effectively eliminate the transmission noise caused by the gear clearance in the transmission of the balance shaft gear pair, and make the gear pair meshing transmission process smoother and smoother, especially when the engine operating speed changes rapidly, the effect is more obvious.

[0013] The engine balance shaft gear set with buffering function of the present invention will be further described below in conjunction with the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a structural schematic diagram of an engine balance shaft driving gear pair in the prior art;

[0015] Figure 2 It is a structural schematic diagram of a driven gear of an engine balance shaft gear set with a buffering function according to the present invention;

[0016] Figure 3 yes Figure 2 Another direction view of the driven gear shown;

[0017] Figure 4 It is a plan view of the buffer gear of the engine balance shaft gear set with buffer function of the present invention;

[0018] Figure 5 is a stereoscopic diagram of a buffer gear of an engine balance shaft gear set with a buffer function according to the present invention;

[0019] Figure 6 It is a three-dimensional diagram of the driving gear and the driven gear of the engine balance shaft gear set with buffer function of the present invention meshing with each other;

[0020] Figure 7 It is a plane view of the driving gear and the driven gear of the engine balance shaft gear set with buffer function of the present invention meshing with each other;

[0021] Figure 8 yes Figure 7 A partial enlarged view of point C;

[0022] Description of the accompanying figures: 1-driving gear, 11-teeth of the driving gear, 12-center hole of the driving gear, 2-driven gear, 21-installation adjustment pin hole, 22-positioning hole, 23-center hole of the driven gear, 24-dynamic balancing weight reduction hole, 25-arc guide step, 26-teeth of the driven gear, 3-buffer gear, 31-elastic arm II, 32-arc guide groove, 33-elastic arm I, 34-circular mounting portion, 35-installation circular hole, 36-buffer gear body, 37-teeth of the buffer gear, 4-eccentric pin, O1-center of the installation circular hole, O2-center of the dividing circle of the buffer gear. DETAILED DESCRIPTION

[0023] like Figures 2 to 7 As shown, the engine balance shaft gear set with buffering function of the present invention includes a driving gear, a driven gear and a buffering gear. The driven gear and the buffering gear constitute a driven gear set. The driving gear is installed on the driving shaft of the engine through the center hole of the driving gear. In this embodiment, the driving shaft is the crankshaft of the engine (not shown in the figure), and the driving gear is used to drive the driven gear set. The driven gear is installed on the balance shaft of the engine (not shown in the figure) through the center hole of the driven gear.

[0024] like Figure 2 , Figure 3 As shown, a circular arc guide step is protruding from one end surface of the driven gear for mounting a buffer gear. A mounting adjustment pin hole is provided on one side of the circular arc guide step of the driven gear. A positioning hole is also provided on the end surface of the driven gear for positioning when connected to the balance shaft. The driven gear is also provided with a dynamic balance weight reduction hole for reducing the weight of the gear.

[0025] like Figure 4 , Figure 5As shown, the buffer gear is an elastic gear made of spring steel. The number of teeth and the module of the buffer gear are the same as those of the driven gear, and the normal pressure angle of the buffer gear is slightly smaller than that of the driven gear. The thickness of the buffer gear is less than that of the driven gear. In this embodiment, the thickness of the buffer gear is only one-third of the thickness of the driven gear. The thickness of the buffer gear is determined according to the thickness of the driven gear. Generally, the thickness of the buffer gear is one-fifth to one-third of the thickness of the driven gear. The buffer gear includes a circular mounting portion, an elastic arm and a buffer gear body. The circular mounting portion is located in the middle of the inner side of the buffer gear. A mounting circular hole is provided in the middle of the circular mounting portion. The center of the mounting circular hole is offset from the center of the indexing circle of the buffer gear. The center of the mounting circular hole of the buffer gear is offset from the center of the indexing circle of the buffer gear by 0.5-2 mm. In this embodiment, the center of the mounting circular hole of the buffer gear is offset from the center of the indexing circle of the buffer gear by 1 mm. Since the center of the mounting circular hole is offset from the center of the indexing circle of the buffer gear, a certain buffer elastic force is formed when the buffer gear is meshed with the driving gear after installation. The elastic arm is formed by extending from the outer edge of the circular ring mounting portion, and the outer end of the elastic arm is connected to the buffer gear body, and an arc guide groove is formed between the elastic arm and the buffer gear body. In this embodiment, the elastic arm of the buffer gear includes an elastic arm I vertically connected to the outer edge of the circular ring mounting portion and an elastic arm II extending from one side of the elastic arm I to form an arc shape, and the arc guide groove is between the elastic arm II and the buffer gear body. The position of the arc guide groove corresponds to the position of the arc guide step of the driven gear, and a gap is provided between the side wall of the arc guide groove and the outer surface of the arc guide step. The elastic arm I can contact the two ends of the arc guide step of the driven gear, and play a limiting role during buffer adjustment.

[0026] like Figure 6 , Figure 7 As shown, a fixing bolt (not shown in the figure) passes through the mounting circular hole of the buffer gear to mount the buffer gear on the end face of one end of the balance shaft, and the buffer gear is close to the end surface of the driven gear, and the arc guide step of the driven gear passes through the arc guide groove of the buffer gear. When the buffer gear is against the end surface of the driven gear, the teeth of the buffer gear and the teeth of the driven gear are misaligned with each other, and the misalignment is slightly larger than the transmission meshing clearance of the gear pair in which the driving gear and the driven gear are meshed. The tooth misalignment of the driven gear set before being installed and meshed with the driving gear can be adjusted by an eccentric pin. The eccentric pin passes through the arc guide groove of the buffer gear and enters the installation adjustment pin hole. The tooth misalignment of the buffer gear and the driven gear can be adjusted by rotating the eccentric pin.

[0027] Before installing the driven gear set on the balance shaft, first install the buffer gear on the driven gear, clamp the elastic arm II on the buffer gear with the eccentric pin, and insert it into the installation adjustment pin hole, rotate the eccentric pin to adjust the tooth profile of the buffer gear and the driven gear to basically coincide, and use bolts through the center hole of the driven gear and the circular hole of the buffer gear to install and fasten the driven gear set on the balance shaft, so that the driven gear set meshes with the driving gear and rotates smoothly. Then pull out the eccentric pin, and use the elastic force formed by the elastic arm I on the buffer gear and the eccentric circular hole of the buffer gear installation after installation to make the driving gear actively mesh with the buffer gear first, and then contact and mesh with the driven gear after buffering.

[0028] After the entire balancing shaft gear pair is installed, the driving gear moves clockwise, and the buffer gear also tends to rotate clockwise due to the material, elastic arm and the center offset structure of the buffer gear. The buffer gear always maintains a small tooth misalignment with the driven gear. During the meshing process between the driven gear set and the driving gear, the driving gear first actively meshes and contacts the buffer gear, and then contacts and meshes with the driven gear after buffering. That is, during the meshing process between the driven gear and the driving gear, the teeth of the driving gear first contact the teeth of the buffer gear and then contact the teeth of the driven gear, driving the balancing shaft to rotate. The present invention assembles the buffer gear at one end of the driven gear and forms a tooth misalignment with the driven gear. During the meshing process between the driven gear set and the driving gear, the driving gear first contacts the buffer gear, and the elastic effect of the buffer gear is used to eliminate the impact of the driving gear on the driven gear of the balancing shaft, thereby avoiding impact noise in the transmission of the balancing shaft gear pair and avoiding gear impact causing failure of the gear pair.

[0029] The above embodiments are only preferred embodiments of the present invention. The structure of the present invention is not limited to the forms listed in the above embodiments. Any modifications, equivalent substitutions, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. An engine balance shaft gear set with a buffering function, comprising a driving gear (1) and a driven gear (2), wherein the driving gear (1) is mounted on the driving shaft of the engine through a driving gear center hole (12), and the driven gear (2) is mounted on the engine balance shaft through a driven gear center hole (23), characterized in that: The driven gear (2) has an arc guide step (25) protruding from one end surface thereof, and also includes a buffer gear (3). The buffer gear (3) is a gear made of spring steel and has elasticity. The number of teeth and the module of the buffer gear (3) are respectively the same as the number of teeth and the module of the driven gear. The thickness of the buffer gear (3) is smaller than the thickness of the driven gear (2). The buffer gear (3) includes a circular ring mounting portion (34), an elastic arm and a buffer gear body (36). The circular ring mounting portion (34) is located in the middle of the inner side of the buffer gear (3). The elastic arm is formed by extending from the outer edge of the circular ring mounting portion (34). The outer end of the elastic arm is connected to the buffer gear body (36). An arc guide groove (32) is formed between the elastic arm and the buffer gear body (36). A mounting circular hole (35) is provided in the middle of the circular ring mounting portion (34). The center (O1) of the mounting circular hole is offset from the center (O2) of the indexing circle of the buffer gear. The fixing bolt passes through the mounting circular hole of the buffer gear (3). The buffer gear (3) is installed on the end surface of one end of the balance shaft through the hole (35), and the buffer gear (3) is against the end surface of the driven gear (2), and the arc guide step (25) of the driven gear (2) passes through the arc guide groove (32) of the buffer gear (3). When the buffer gear (3) is against the end surface of the driven gear (2), the teeth (37) of the buffer gear and the teeth (26) of the driven gear are offset from each other, and the offset is slightly greater than the meshing amount of the driving gear (1) and the driven gear (2). The gear pair transmission meshing clearance is such that during the meshing process between the driven gear (2) and the driving gear (1), the teeth (11) of the driving gear first contact the teeth (37) of the buffer gear and then contact the teeth (26) of the driven gear; the center (O1) of the mounting circular hole of the buffer gear (3) and the center (O2) of the indexing circle of the buffer gear are offset by 0.5-2 mm; and the end surface of the driven gear (2) is also provided with a positioning hole (22) for positioning when connected to the balance shaft.

2. The engine balance shaft gear set with buffering function as claimed in claim 1, characterized in that: The elastic arm of the buffer gear (3) comprises an elastic arm I (33) vertically connected to the outer edge of the annular mounting portion (34) and an elastic arm II (31) extending from one side of the elastic arm I (33) to form an arc shape, and an arc-shaped guide groove (32) is between the elastic arm II (31) and the buffer gear body (36), the position of the arc-shaped guide groove (32) corresponds to the position of the arc-shaped guide step (25) of the driven gear (2), and a gap is provided between the side wall of the arc-shaped guide groove (32) and the outer surface of the arc-shaped guide step (25).

3. The engine balance shaft gear set with buffering function as claimed in claim 1, characterized in that: A mounting adjustment pin hole (21) is provided on one side of the circular arc guide step (25) of the driven gear (2); the eccentric pin (4) passes through the circular arc guide groove (32) of the buffer gear (3) and enters the mounting adjustment pin hole (21); and the tooth misalignment amount between the buffer gear (3) and the driven gear (2) can be adjusted by rotating the eccentric pin (4).

4. The engine balance shaft gear set with buffering function as claimed in claim 1, characterized in that: The driven gear (2) is also provided with a dynamic balancing weight-reducing hole (24) for reducing the weight of the gear.

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