阅读说明：本技术 一种汽车发动机平衡轴机构 (Balance shaft mechanism of automobile engine ) 是由 吴琪 吴广权 易敬华 于 2019-04-19 设计创作，主要内容包括：本发明提供一种汽车发动机平衡轴机构,包括平衡轴齿轮、平衡轴、第一轴承、第二轴承、第一配重以及第二配重,平衡轴齿轮用于与发动机曲轴箱内的曲轴齿轮啮合,平衡轴包括相对设置的第一端部和第二端部,在第一端部和第二端部之间连接有中间连接段,第一端部固定安装有第一轴承、平衡轴齿轮和第一配重,第一轴承比平衡轴齿轮和第一配重更靠近第二端部,第二端部固定安装有第二轴承和第二配重,第二轴承比第二配重更靠近第一端部,第一配重和第二配重的质心偏移方向呈°相对设置,第一配重和第二配重产生的不平衡力矩与发动机曲柄连杆机构产生的不平衡力矩大小相同、方向相反。本发明的汽车发动机平衡轴机构的结构更简单,且便于装配。(The invention provides an automobile engine balance shaft mechanism, which comprises a balance shaft gear, a balance shaft, a first bearing, a second bearing, a first counterweight and a second counterweight, wherein the balance shaft gear is used for being meshed with a crankshaft gear in an engine crankcase, the balance shaft comprises a first end part and a second end part which are oppositely arranged, an intermediate connecting section is connected between the first end part and the second end part, the first bearing, the balance shaft gear and the first counterweight are fixedly arranged at the first end part, the first bearing is closer to the second end part than the balance shaft gear and the first counterweight, the second bearing and the second counterweight are fixedly arranged at the second end part, the second bearing is closer to the first end part than the second counterweight, the centroid offset directions of the first counterweight and the second counterweight are oppositely arranged in an angle, and the unbalanced moment generated by the first counterweight and the second counterweight is the same as the unbalanced moment generated by an engine crank connecting rod mechanism in size, The direction is opposite. The balance shaft mechanism of the automobile engine is simpler in structure and convenient to assemble.)

1. The engine balance shaft mechanism is characterized by comprising a balance shaft gear (1), a balance shaft (2), a first bearing (3), a second bearing (4), a first balance weight (5) and a second balance weight (6), wherein the balance shaft gear (1) is used for being meshed with a crankshaft gear in an engine crankcase, the balance shaft (2) comprises a first end part (21) and a second end part (22) which are arranged oppositely, an intermediate connecting section (23) is connected between the first end part (21) and the second end part (22), the first bearing (3), the balance shaft gear (1) and the first balance weight (5) are fixedly installed at the first end part (21), the first bearing (3) is closer to the second end part (22) than the balance shaft gear (1) and the first balance weight (5), and the second bearing (4) and the second balance weight (6) are fixedly installed at the second end part (22), the second bearing (4) is closer to the first end (21) than the second counterweight (6), the first counterweight (5) and the second counterweight (6) are oppositely arranged, the direction of mass center offset is 180 degrees, and the unbalance moment generated by the first counterweight (5) and the second counterweight (6) is the same as the unbalance moment generated by an engine crank-link mechanism in size and opposite in direction.

2. The engine balance shaft mechanism according to claim 1, wherein, of the outer diameter of the first end portion (21), the outer diameter of the second end portion (22), and the outer diameter of the intermediate connecting section (23), the outer diameter of the second end portion (22) is largest, and the outer diameter of the first end portion (21) is smallest.

3. The engine balance shaft mechanism according to claim 1, wherein a third counterweight (7) and a fourth counterweight (8) are further arranged on the intermediate connecting section (23), the third counterweight (7) and the fourth counterweight (8) are oppositely arranged, the direction of mass center offset is 180 degrees, and the first counterweight (5), the second counterweight (6), the third counterweight (7) and the fourth counterweight (8) jointly generate an unbalance moment which is the same as the size and opposite to the unbalance moment generated by the engine crank link mechanism.

4. The engine balance shaft mechanism of claim 3 wherein said third counterweight (7) is proximate said second end (22) and said fourth counterweight (8) is proximate said first end (21), said third counterweight (7) having a direction of center of mass offset that is the same as the direction of center of mass offset of said second counterweight (6), said fourth counterweight (8) having a direction of center of mass offset that is the same as the direction of center of mass offset of said first counterweight (5).

5. The engine balance shaft mechanism according to claim 3, wherein the balance shaft (2) is a balance shaft made of cast iron.

6. The engine balance shaft mechanism of claim 2 wherein said first bearing (3) is a ball bearing and said second bearing (4) is a needle bearing.

7. The engine balance shaft mechanism of claim 6, wherein the second bearing (4) comprises an integrally formed needle bearing outer race (41), a cylindrical needle roller (42) and a needle bearing cage (43), a needle bearing inner race (44) is arranged between the cylindrical needle roller (42) and the balance shaft (2), and the needle bearing inner race (44) is in interference fit with the balance shaft (2).

8. The engine balance shaft mechanism according to claim 1, wherein the balance shaft gear (1) is provided with a first shaft hole (11), the first weight (5) is provided with a second shaft hole (51), the first end portion (21) of the balance shaft (2) is provided with a threaded hole (211), the balance shaft gear (1) and the first weight (5) are mounted to the balance shaft (2) in such a manner that the first shaft hole (11) and the second shaft hole (51) are fitted over the balance shaft (2), and a bolt (9) is passed through the first shaft hole (11) and the second shaft hole (51) and screwed into the threaded hole (211) to fasten the balance shaft gear (1) and the first weight (5) to the balance shaft (2).

9. The engine balance shaft mechanism according to claim 1, wherein the balance shaft gear (1) is provided with a first shaft hole (11), the first counterweight (5) is provided with a second shaft hole (51), the second shaft hole (51) is provided with a first positioning surface (511) with a circular cross section, the first end portion (21) of the balance shaft (2) is provided with a second positioning surface (211) with a circular cross section, which is matched with the first positioning surface (511), and the first counterweight (5) is sleeved on the first end portion (21) of the balance shaft (2) in a manner that the first positioning surface (511) is matched with the second positioning surface (211).

Technical Field

The invention relates to the field of automobile engines, in particular to a balance shaft mechanism of an automobile engine.

Background

As global climate problems continue to worsen, the country pays more and more attention to environmental protection, and legislation and requirements on automobile emissions have become more and more stringent. And the engine as the source of automobile emission is continuously developing towards energy conservation, emission reduction and miniaturization. When the engine works normally, a large amount of vibration and noise are generated, which directly affect the comfort of the whole vehicle and the structural strength of the engine. Generally, reciprocating inertia forces of crank link mechanisms of engines with odd numbers of cylinders, for example, 3-cylinder and 5-cylinder engines are difficult to balance according to the number of cylinders of the engines, and a balance shaft mechanism is generally required to be added for balance.

For example, patent publication No. CN103485888A discloses a balance shaft mechanism of an engine and an engine assembly, the balance shaft mechanism includes a balance shaft, a balance shaft gear located at one end of the balance shaft, a balance shaft housing, and balance weights located at two ends of the balance shaft. The balance shaft shell covers the balance shaft, the balance weight and the balance shaft gear and is used for installing and fixing the balance shaft mechanism to the engine cylinder body. However, since the balance shaft housing needs to be designed in a profiling manner according to the shapes of the balance shaft, the balance shaft gear and the counterweight, the structure of the balance shaft housing is often complicated, so that the manufacturing cost is increased, and the assembly of the balance shaft mechanism is difficult. In addition, the balance shaft mechanism only arranges the balance weights at two ends of the balance shaft, space utilization is not optimal, and the middle part of the balance shaft is too thin, so that the hardness of the balance shaft is insufficient.

Disclosure of Invention

The invention aims to provide a balance shaft mechanism of an automobile engine, which is simple in structure and convenient to assemble.

The invention provides an automobile engine balance shaft mechanism, which comprises a balance shaft gear, a balance shaft, a first bearing, a second bearing, a first counterweight and a second counterweight, wherein the balance shaft gear is used for being meshed with a crankshaft gear in an engine crankcase, the balance shaft comprises a first end part and a second end part which are oppositely arranged, an intermediate connecting section is connected between the first end part and the second end part, the first bearing, the balance shaft gear and the first counterweight are fixedly arranged at the first end part, the first bearing is closer to the second end part than the balance shaft gear and the first counterweight, the second bearing and the second counterweight are fixedly arranged at the second end part, the second bearing is closer to the first end part than the second counterweight, the centroid offset directions of the first counterweight and the second counterweight are oppositely arranged in an angle, and the unbalanced moment generated by the first counterweight and the second counterweight is the same as the unbalanced moment generated by an engine crank connecting rod mechanism in size, The direction is opposite.

Further, of the outer diameters of the first end portion, the second end portion, and the intermediate connection section, the outer diameter of the second end portion is the largest, and the outer diameter of the first end portion is the smallest.

Furthermore, a third counterweight and a fourth counterweight are further arranged on the middle connecting section, the mass center offset directions of the third counterweight and the fourth counterweight are oppositely arranged in an angle, and the unbalanced moment generated by the first counterweight, the second counterweight, the third counterweight and the fourth counterweight together is the same as the unbalanced moment generated by the engine crank-link mechanism in size and opposite in direction.

Further, the third counterweight is close to the second end portion, the fourth counterweight is close to the first end portion, the centroid offset direction of the third counterweight is the same as the centroid offset direction of the second counterweight, and the centroid offset direction of the fourth counterweight is the same as the centroid offset direction of the first counterweight.

Further, the balance shaft is made of cast iron.

Further, the first bearing is a ball bearing, and the second bearing is a needle bearing.

Furthermore, the second bearing comprises a needle bearing outer ring, a cylindrical needle roller and a needle bearing retainer which are integrally formed, a needle bearing inner ring is arranged between the cylindrical needle roller and the balance shaft, and the needle bearing inner ring is in interference fit with the balance shaft.

Further, the balance shaft gear is provided with a first shaft hole, the first balance weight is provided with a second shaft hole, a first end portion of the balance shaft is provided with a threaded hole, the balance shaft gear and the first balance weight are mounted on the balance shaft in a mode that the first shaft hole and the second shaft hole are sleeved on the balance shaft, and a bolt penetrates through the first shaft hole and the second shaft hole and is screwed into the threaded hole to fasten the balance shaft gear and the first balance weight on the balance shaft.

Further, the balance shaft gear is provided with a first shaft hole, the first balance weight is provided with a second shaft hole, the second shaft hole is provided with a first positioning surface with a circular cutting cross section, the first end portion of the balance shaft is provided with a second positioning surface with a circular cutting cross section matched with the first positioning surface, and the first end portion of the balance shaft is sleeved with the first balance weight in a mode that the first positioning surface is matched with the second positioning surface.

In summary, since the balance shaft mechanism of the automobile engine of the present invention eliminates the structure of the balance shaft housing, the first bearing is closer to the second end portion than the balance shaft gear and the first counterweight, and the second bearing is closer to the first end portion than the second counterweight, after the first bearing and the second bearing are mounted in the mounting hole of the engine cylinder, the balance shaft can be inserted through the through hole of the cylinder, the first bearing and the second bearing, and then the balance shaft gear, the first counterweight and the second counterweight are mounted on the balance shaft, so that the balance shaft mechanism of the automobile engine of the present invention has a simpler structure and is convenient to assemble.

Drawings

Fig. 1 is a perspective view of a balance shaft mechanism of an automobile engine according to an embodiment of the present invention.

Fig. 2 is an exploded perspective view of a balance shaft mechanism of an automobile engine according to an embodiment of the present invention.

Fig. 3 is an exploded perspective view of another perspective view of a balance shaft mechanism of an automobile engine according to an embodiment of the invention.

Fig. 4 is a cross-sectional view of a balance shaft mechanism of an automobile engine according to an embodiment of the present invention.

Fig. 5 is a B-B direction sectional view of the balance shaft mechanism of the automobile engine shown in fig. 4.

Fig. 6 is a cross-sectional view of the automobile engine cylinder block without the balance shaft mechanism of the automobile engine according to the embodiment of the invention.

Fig. 7 is a sectional view of an automobile engine block with an automobile engine balance shaft mechanism installed according to an embodiment of the present invention.

Detailed Description

The following detailed description of embodiments of the present invention is provided in connection with the accompanying drawings and examples. The following examples are intended to illustrate the invention but are not intended to limit the scope of the invention.

As shown in fig. 1 to 4, the balance shaft mechanism of the automobile engine according to the embodiment of the present invention includes a balance shaft gear 1, a balance shaft 2, a first bearing 3, a second bearing 4, a first counterweight 5, and a second counterweight 6.

The balance shaft 2 is made of cast iron. The balance shaft 2 comprises a first end portion 21 and a second end portion 22 arranged opposite to each other, and an intermediate connecting section 23 is connected between the first end portion 21 and the second end portion 22. In the present embodiment, of the outer diameters of the first end portion 21, the second end portion 22, and the intermediate connecting section 23, the outer diameter of the second end portion 22 is the largest, and the outer diameter of the first end portion 21 is the smallest.

The second end 22 is fixedly mounted with the second bearing 4 and the second balance weight 6. Preferably, the second balance weight 6 is integrally formed at the second end 22 of the balance shaft 2, so that additional parts assembly processes and parts management costs can be reduced. The second bearing 4 is closer to the first end 21 than the second counterweight 6, the second bearing 4 preferably being a needle bearing. The second bearing 4 includes an integrally formed needle bearing outer race 41, cylindrical needles 42, and a needle bearing holder 43. A needle bearing inner ring 44 is arranged between the cylindrical needle roller 42 and the balance shaft 2, the needle bearing inner ring 44 is sleeved on the balance shaft 2 in an interference fit manner, and the needle bearing inner ring 44 can share the radial force applied to the second end 22 of the balance shaft 2, so that the balance shaft 2 is protected.

The first end portion 21 is fixedly mounted with the first bearing 3, the balance shaft gear 1, and the first balance weight 5. The balance shaft gear 1 is used for meshing with a crankshaft gear in an engine crankcase. The first bearing 3 is preferably a ball bearing, the first bearing 3 comprises an inner ball bearing ring 31, a rolling ball 32, a ball bearing retainer 33 and an outer ball bearing ring 34 which are integrally formed, the first bearing 3 is sleeved on the first end portion 21, and the first bearing 3 is closer to the second end portion 22 than the balance shaft gear 1 and the first counterweight 5. The side of the first bearing 3 close to the second end 22 (the right side in fig. 4) abuts against a thrust surface 24 on the balance shaft 2, and the thrust surface 24 is used for limiting the side of the first bearing 3 close to the second end 22. The side of the first bearing 3 closer to the first end portion 21 (the left side in fig. 4) abuts against a retainer ring 25 attached to the balance shaft 2, and the retainer ring 25 restricts vibration of the first bearing 3 closer to the first end portion 21.

The balance shaft gear 1 is provided with a first shaft hole 11, the first balance weight 5 is provided with a second shaft hole 51, and the first end portion 21 of the balance shaft 2 is opened with a screw hole 211 from the end surface on the outer side thereof inward in the axial direction. The balance shaft gear 1 and the first balance weight 5 are mounted on the balance shaft 2 in a manner that the first shaft hole 11 and the second shaft hole 51 are sleeved on the balance shaft 2, and a bolt 9 passes through the first shaft hole 11 and the second shaft hole 51 and is screwed into the threaded hole 211 to fasten the balance shaft gear 1 and the first balance weight 5 on the balance shaft 2. The mass center offset directions of the first balance weight 5 and the second balance weight 6 are opposite to each other at 180 degrees, and the unbalance moment generated by the first balance weight 5 and the second balance weight 6 is the same as the unbalance moment generated by the engine crank link mechanism in size and opposite to the unbalance moment generated by the engine crank link mechanism in direction.

In addition, in order to facilitate the installation of the first balance weight 5 and the second balance weight 6, the center of mass of the first balance weight 5 and the center of mass of the second balance weight 6 are arranged oppositely at 180 °, as shown in fig. 3 and 5, the second shaft hole 51 has a first positioning surface 511 with a circular cross section (i.e., the portion of the remaining circle obtained by cutting the circle by a straight line), the first end portion 21 of the balance shaft 2 has a second positioning surface 211 with a circular cross section, which is matched with the first positioning surface 511, and the first balance weight 5 is sleeved on the first end portion 21 of the balance shaft 2 in a manner that the first positioning surface 511 is matched with the second positioning surface 211.

Furthermore, the middle connecting section 23 is also provided with a third counterweight 7 and a fourth counterweight 8, the mass center offset directions of the third counterweight 7 and the fourth counterweight 8 are opposite to each other by 180 degrees, and the unbalanced moment generated by the first counterweight 5, the second counterweight 6, the third counterweight 7 and the fourth counterweight 8 together is the same as the unbalanced moment generated by the engine crank link mechanism in size and opposite in direction. Further, the third balance weight 7 is close to the second end portion 22, the fourth balance weight 8 is close to the first end portion 21, the direction of the centroid shift of the third balance weight 7 is the same as the direction of the centroid shift of the second balance weight 6, and the direction of the centroid shift of the fourth balance weight 8 is the same as the direction of the centroid shift of the first balance weight 5. By providing the third balance weight 7 and the fourth balance weight 8 on the intermediate connecting section 23, the space of the balance shaft mechanism can be fully utilized to arrange more balance weights. In addition, because the third counterweight 7 and the fourth counterweight 8 are additionally arranged on the middle connecting section 23, the radial thickness of the middle connecting section 23 of the balance shaft 2 is increased, so that the hardness of the middle connecting section 23 of the balance shaft 2 is increased, and the wear resistance and the service life of the balance shaft 2 are further increased. Since the balance shaft 2 has an enhanced wear resistance, the balance shaft 2 can be made of cast iron, which can save cost compared to the conventional balance shaft made of steel.

A method of mounting the balance shaft mechanism of the automobile engine according to an embodiment of the present invention to the engine block of the automobile is described below with reference to fig. 6 to 7. The engine block 111 according to an embodiment of the present invention includes a through hole 1110 through which the balance shaft 2 passes, a first mounting hole 1111 located at a first end of the through hole 1110 and adapted to be in interference fit with the outer race of the first bearing 3, a second mounting hole 1112 located at a second end of the through hole 1110 and adapted to be in interference fit with the outer race of the second bearing 4, and a mounting groove 1113 located at a first end of the through hole 1110 and adapted to be in interference fit with the retainer ring 25.

The mounting method for mounting the automobile engine balance shaft mechanism on the automobile engine cylinder body comprises the following steps:

installing the first bearing 3 and the second bearing 4 in the installation hole of the engine block, specifically, installing the outer ring of the first bearing 3 in the first installation hole 1111 in an interference fit manner to complete the installation of the first bearing 3, and installing the outer ring of the second bearing 4 in the second installation hole 1112 in an interference fit manner to complete the installation of the second bearing 4;

a needle bearing inner race 44 (inner race of the second bearing 4) is fitted to the second end 22 of the balance shaft 2 with interference fit;

installing the retainer ring 25 in the installation groove 1113 of the engine cylinder block 111 in an interference fit manner;

starting from the first end 21, the balance shaft 2 is sequentially passed through the second bearing 4 and the first bearing 3 until the second bearing 4 and the first bearing 3 are positioned at the predetermined mounting position on the balance shaft 2, and in the present embodiment, when the side of the inner ring of the first bearing close to the second end is in contact with the thrust surface 24 on the balance shaft 2, the predetermined mounting position of the second bearing 4 and the first bearing 3 on the balance shaft 2 can be determined;

the balance shaft gear 1 and the first balance weight 5 are fixedly installed at the first end portion 21 of the balance shaft 2, in this embodiment, the balance shaft gear 1 and the first balance weight 5 are installed on the balance shaft 2 in a manner that the first shaft hole 11 and the second shaft hole 51 are sleeved on the balance shaft 2, and then the bolt 9 is threaded through the first shaft hole 11 and the second shaft hole 51 and screwed into the threaded hole 211, so that the balance shaft gear 1 and the first balance weight 5 are fastened on the balance shaft 2.

In the present embodiment, of the outer diameters of the first end portion 21, the second end portion 22, and the intermediate connecting section 23, the outer diameter of the second end portion 22 is the largest, and the outer diameter of the first end portion 21 is the smallest; however, the present invention is not limited to this, and the outer diameter of the second end portion 22 may be minimized and the outer diameter of the first end portion 21 may be maximized among the outer diameters of the first end portion 21, the second end portion 22, and the intermediate connecting section 23, and in this case, when the automobile engine balancer shaft mechanism is mounted on the automobile engine block, the balancer shaft 2 is inserted from the second end portion 21 through the first bearing 3 and the second bearing 4 in this order until the first bearing 3 and the second bearing 4 are positioned at predetermined mounting positions on the balancer shaft 2, and in this case, the second weight 6 needs to be provided separately from the balancer shaft 2.

In summary, since the balance shaft mechanism of the automobile engine of the present invention eliminates the structure of the balance shaft housing, by making the first bearing 3 closer to the second end 22 than the balance shaft gear 1 and the first balance weight 5, and making the second bearing 4 closer to the first end 21 than the second balance weight 6, after the first bearing 3 and the second bearing 4 are mounted in the mounting hole of the engine cylinder, the balance shaft 2 can be inserted through the through hole of the cylinder, the first bearing 3 and the second bearing 4, and then the balance shaft gear 1, the first balance weight 5, and the second balance weight 6 are mounted on the balance shaft 2, so the balance shaft mechanism of the automobile engine of the present invention has a simpler structure and is easy to assemble. Of the outer diameters of the first end portion 21, the second end portion 22 and the intermediate connecting section 23, the outer diameter of the first end portion 21 is minimized by maximizing the outer diameter of the second end portion 22, and it is also facilitated to pass the balance shaft 2 through the second bearing 4 and the first bearing 3 in order from the first end portion 21. Of the outer diameters of the first end portion 21, the second end portion 22 and the intermediate coupling segment 23, when the outer diameter of the first end portion 21 is the smallest and the outer diameter of the second end portion 22 is the largest, a ball bearing may be mounted on the first end portion 21, a needle bearing may be mounted on the second end portion 22, the ball bearing may be small in size, so that a certain radial force may be received by the ball bearing, and a certain cost may be saved, and since the outer diameter of the second end portion 22 is excessively large, the cost of mounting the ball bearing may be excessively high, the needle bearing may be mounted on the second end portion 22, and a needle bearing inner race 44 may be provided between the needle rollers 42 of the needle bearing and the balance shaft 2 so that a certain radial force may be received by the needle bearing inner race 44. The technical features of the embodiments described above may be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the embodiments described above are not described, but should be considered as being within the scope of the present specification as long as there is no contradiction between the combinations of the technical features.

The above description is only for the specific embodiments of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art can easily conceive of the changes or substitutions within the technical scope of the present invention, and all the changes or substitutions should be covered within the scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the appended claims.