Engine balance shaft assembly

Abstract

The utility model discloses an engine balance shaft assembly which comprises a balance shaft, a balance block assembly, a first bearing assembly, a second bearing assembly and a driving gear, the balance block assembly is arranged on the surface of a balance shaft body, and the balance block assembly and the balance shaft are of an integrated structure. The first bearing assembly and the second bearing assembly are installed on the two sides of the balance shaft in a pressed mode respectively, the driving gear is installed on the balance shaft in a pressed mode and located on the outer side of the second bearing assembly, and the balance block and the balance shaft are cast into a whole, so that assembling parts are reduced; the two bearings and the driving gear are assembled on the balance shaft in a press-fitting manner, so that parts for mounting bolts are reduced, the cost is greatly reduced, and the assembly scheme is simple and easy to operate.

Description

Technical Field

[0001] The utility model relates to the technical field of engine parts, in particular to an engine balance shaft assembly. Background Art

[0002] In the field of engines, a balance shaft is usually used to balance the first-order and second-order reciprocating inertia forces of the engine piston connecting rod mechanism.

[0003] There are two types of balance shaft assembly on the engine, one is a box-type structure and the other is a combined structure.

[0004] like Figure 1 The figure shows a box-type balance shaft. Figure 1 It mainly includes: a balancing shaft assembly 1, a balancing shaft mounting bolt 2, and a cylinder block 3. The balancing shaft assembly 1 is composed of two balancing shafts assembled in a box, which are assembled on the bottom of the cylinder block 3 through the balancing shaft mounting bolt 2 and driven by a chain or a gear;

[0005] Another type is Figure 2 As shown, Figure 2 It mainly includes: mounting bolts 4, balancing blocks 5, balancing shaft driving gears 6, retaining rings 7, bearings 8, balancing shafts 9, bearing outer rings 10, and needle roller bearings 11.

[0006] The balancing shaft 9 is a modular structure. The balancing block 5, the balancing shaft driving gear 6 and other parts are assembled on the balancing shaft 9 by installing bolts 4, and then the balancing shaft 9 is assembled on the side of the cylinder body. The balancing shaft 9 and the cylinder body are matched with each other through bearings 8, ball bearings 11, bearing outer rings 10 and the like.

[0007] The above-mentioned cassette structure balance shaft and combined structure balance shaft have the following disadvantages:

[0008] (1) The balance shaft has many parts, which makes assembly complex and difficult, and the assembly efficiency is low;

[0009] (2) Bolts are required to tighten the balance block and the balance shaft drive gear, and a high-strength bolt needs to be newly designed, which has the disadvantages of long assembly cycle and high cost.

[0010] It can be seen that providing an engine balance shaft assembly with a simple structure and low cost is an issue that needs to be urgently addressed in the art. Utility Model Content

[0011] In view of the above technical problems existing in the existing balance shaft, the purpose of the utility model is to provide an engine balance shaft assembly, which reduces the parts of the balance shaft, simplifies assembly, improves assembly efficiency and reduces parts costs.

[0012] In order to achieve the above-mentioned purpose, the utility model provides an engine balance shaft assembly, including a balance shaft, a balance block assembly, a first bearing assembly, a second bearing assembly, and a driving gear. The balance block assembly is arranged on the surface of the balance shaft body, and the balance block assembly and the balance shaft are an integrated structure. The first bearing assembly and the second bearing assembly are respectively pressed on both sides of the balance shaft, and the driving gear is pressed on the balance shaft and is located on the outside of the second bearing assembly.

[0013] Furthermore, the balance shaft is an integrally formed structure, comprising a shaft body, a first mounting boss, a second mounting boss and a third mounting boss;

[0014] The first mounting boss is provided at one end of the shaft body and is used for mounting the first bearing assembly;

[0015] The two ends of the second mounting boss are respectively connected to the other end of the shaft body and one end of the third mounting boss. The second mounting boss is used to install the second bearing assembly, and the third mounting boss is used to install the driving gear.

[0016] Furthermore, a mounting groove is provided on the outer peripheral surface of the first mounting boss, wherein the retaining ring can be installed therein, and a first annular stopper is provided at the connection between the first mounting boss and the shaft body;

[0017] The retaining ring is located on the outside of the first bearing assembly, and the first annular limiting platform is located on the inside of the first bearing assembly. The retaining ring and the first annular limiting platform cooperate to limit the position of the first bearing assembly.

[0018] Furthermore, the second mounting boss and the third mounting boss are coaxially distributed, and the diameter of the second mounting boss is larger than that of the third mounting boss, and a step surface can be formed between the second mounting boss and the third mounting boss.

[0019] Furthermore, a second annular limit platform is provided at the connection between the second mounting boss and the shaft body, the second annular limit platform abuts against the second bearing assembly, and the second annular limit platform limits the position of the second bearing assembly on the second mounting boss.

[0020] Furthermore, the outer ring of the first bearing assembly and the external mounting hole are interference fit, and the inner ring and the first mounting boss are press-fitted and transition fit is adopted.

[0021] Furthermore, an interference fit is adopted between the inner ring of the second bearing assembly and the second mounting boss, and between the driving gear and the third mounting boss, and a transition fit is adopted between the outer ring of the second bearing assembly and the external mounting hole.

[0022] Furthermore, both the first bearing assembly and the second bearing assembly adopt ball bearings.

[0023] Furthermore, the balancing weight assembly includes a plurality of balancing weights, and the plurality of balancing weights are integrally formed on the outer peripheral surface of the shaft body.

[0024] The engine balancing shaft assembly provided by the utility model reduces the number of assembly parts by casting the balancing block and the balancing shaft as one body; and assembles two bearings and a driving gear on the balancing shaft by press-fitting, thereby reducing the number of mounting bolt parts, greatly reducing the cost; and the assembly scheme is simple and easy to operate. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The present invention is further described below in conjunction with the accompanying drawings and specific implementations.

[0026] Figure 1 It is a structural schematic diagram of a box-type structure balance shaft in the prior art;

[0027] Figure 2 It is a structural schematic diagram of a combined structure balance shaft in the prior art;

[0028] Figure 3 This is a schematic diagram of the exploded structure of the engine balance shaft assembly provided by the utility model;

[0029] Figure 4 The utility model is a schematic diagram of the overall structure of the engine balance shaft assembly.

[0030] Illustration Description:

[0031] The balance shaft 100, the first bearing assembly 300, the second bearing assembly 400, the driving gear 500,

[0032] The shaft body 110 , the first mounting boss 120 , the mounting groove 121 , the retaining ring 122 , the first annular limiting platform 123 , the second mounting boss 130 , the third mounting boss 140 , the step surface 150 , the second annular limiting platform 160 , and the balancing block 210 . DETAILED DESCRIPTION

[0033] In order to make the technical means, creative features, objectives and effects achieved by the present invention easy to understand, the present invention is further described below with reference to specific illustrations.

[0034] See also Figure 3 , Figure 4 , which is a schematic structural diagram of the engine balance shaft assembly provided by the utility model.

[0035] According to the drawings, it can be known that the engine balancing shaft assembly provided by the utility model includes five components: a balancing shaft 100, a balancing block assembly, a first bearing assembly 300, a second bearing assembly 400, and a driving gear 500.

[0036] The balancing shaft 100 is a structural main body used to carry other components.

[0037] Furthermore, the balancing weight assembly is arranged on the surface of the balancing shaft 100, and the balancing weight assembly and the balancing shaft 100 are an integrated structure;

[0038] The first bearing assembly 300 and the second bearing assembly 400 are respectively press-fitted on both sides of the balancing shaft 100 to support the rotation of the balancing shaft 100;

[0039] The driving gear 500 is press-fitted on the balance shaft 100 and is located outside the second bearing assembly 400;

[0040] The balancing shaft 100, the balancing block assembly and the driving gear 500 form a balancing system. The driving gear 500 meshes with the crankshaft gear in the engine and is driven by the driving gear 500 when the engine rotates. The rotation direction of the balancing shaft 100 is opposite to that of the engine crankshaft, and the rotation speed is the same as the crankshaft rotation speed.

[0041] In the prior art, the balancing block and the driving gear need to be assembled on the balancing shaft by bolts, which requires a high-strength bolt for installation, which is not only costly, but also has many parts, making the structure complicated, and the assembly is also cumbersome and time-consuming;

[0042] Compared with the prior art, the balancing block assembly in this solution is directly integrated with the balancing shaft 100, and the driving gear 500, the first bearing assembly 300, and the second bearing assembly 400 are installed in a press-fit manner, and no bolts are required for assembly, which can reduce costs and improve assembly convenience.

[0043] Specifically, the balancing shaft 100 is an integrally formed structure, and includes a shaft body 110, a first mounting boss 120, a second mounting boss 130, and a third mounting boss 140;

[0044] The first mounting boss 120 is disposed at one end of the shaft body 110 and is used to mount the first bearing assembly 300;

[0045] Two ends of the second mounting boss 130 are respectively connected to the other end of the shaft body 110 and one end of the third mounting boss 140 . The second mounting boss 130 is used to mount the second bearing assembly 400 , and the third mounting boss 140 is used to mount the driving gear 500 .

[0046] The first mounting boss 120, the second mounting boss 130 and the third mounting boss 140 are all cylindrical structures with circular cross-sections;

[0047] The outer peripheral surface of the first mounting boss 120 can be used for assembling the inner ring of the first bearing assembly 300;

[0048] A mounting groove 121 is provided on the outer peripheral surface of the first mounting boss 120, and the retaining ring 122 can be installed in the mounting groove 121. A first annular stopper 123 is provided at the connection between the first mounting boss 120 and the shaft body 110.

[0049] The retaining ring 122 is located on the outside of the first bearing assembly 300, and the first annular limit platform 123 is located on the inside of the first bearing assembly 300. The retaining ring 122 and the first annular limit platform 123 cooperate to limit the position of the first bearing assembly 300, and clamping it between the two can limit the axial movement of the first bearing assembly 300 relative to the balance shaft 100.

[0050] The second mounting boss 130 and the third mounting boss 140 are coaxially distributed, and the diameter of the second mounting boss 130 is larger than that of the third mounting boss 140, and a step surface 150 can be formed between the second mounting boss 130 and the third mounting boss 140;

[0051] The step surface 150 is used to limit the driving gear 500 to prevent the driving gear 500 pressed on the third mounting boss 140 from being assembled on the second mounting boss 130;

[0052] A second annular limit platform 160 is provided at the connection between the second mounting boss 130 and the shaft body 110. The second annular limit platform 160 contacts the second bearing assembly 400. The second annular limit platform 160 limits the position of the second bearing assembly 400 on the second mounting boss 130 and can limit the second bearing assembly 400 from moving to the shaft body 110.

[0053] The outer ring of the first bearing assembly 300 and the external mounting hole adopt interference fit, and the inner ring and the first mounting boss 120 are press-fitted and transition fit is adopted.

[0054] Based on the above technical solution, when installing the balancing shaft provided by this solution, the outer ring of the first bearing assembly 300 is first installed with an interference fit on the cylinder body mounting hole, and then the first mounting boss 120 is inserted into the inner ring of the first bearing assembly 300 to complete the assembly. The inner ring of the first bearing assembly 300 and the first mounting boss 120 are transitionally fitted, so that the balancing shaft can be installed very conveniently.

[0055] Interference fit is adopted between the inner ring of the second bearing assembly 400 and the second mounting boss 130 as well as between the driving gear 500 and the third mounting boss 140, and transition fit is adopted between the outer ring of the second bearing assembly 400 and the external mounting hole for easy assembly.

[0056] Since the second bearing assembly 400 and the second mounting boss 130 as well as the driving gear 500 and the third mounting boss 140 are interference fit, the second bearing assembly 400 and the second mounting boss 130 can be relatively axially fixed after installation to avoid axial movement.

[0057] During assembly, in this example, it is preferred to assemble by cooling the second mounting boss 130 and the third mounting boss 140 with liquid nitrogen or heating the second bearing assembly 400 and the driving gear 500 to achieve an interference fit based on the principle of thermal expansion and contraction.

[0058] In some embodiments of the present invention, both the first bearing assembly 300 and the second bearing assembly 400 are ball bearings.

[0059] The balancing weight assembly includes a plurality of balancing weights 210 , and the plurality of balancing weights 210 are integrally formed on the outer peripheral surface of the shaft body 110 in sequence.

[0060] The present solution does not limit the structure of the shaft body 110, the number and structure of the balancing blocks 210, and can be determined according to actual conditions. For example, four balancing blocks 210 are preferably used in the present solution, and the balancing blocks 210 are preferably eccentric blocks with a fan-shaped shape as a whole. The shaft body 110 in the present solution preferably has a fan-shaped cross-section.

[0061] The following example illustrates the assembly process of the present invention in a specific application. It should be noted that the following content is only a specific application example of the present solution and does not constitute a limitation to the present solution.

[0062] First, the outer ring of the first bearing assembly 300 is pressed into the mounting hole of the cylinder body, and the first bearing assembly 300 and the mounting hole are interference fit; then the inner ring of the second bearing assembly 400 is pressed onto the second mounting boss 130 by interference fit, and then the driving gear 500 is precisely controlled by the tooling and pressed onto the third mounting boss 140 by interference fit;

[0063] The assembled balance shaft is then assembled into the cylinder body, the first mounting boss 120 is installed with the inner ring of the first bearing assembly 300 installed in the mounting hole of the cylinder body by transition fit, and the retaining ring 122 is assembled in the mounting groove 121 to limit the axial movement of the balance shaft.

[0064] Finally, the outer ring of the second bearing assembly 400 is installed with the mounting hole of the cylinder body by transition fit, and the driving gear 500 is meshed with the crankshaft gear in the cylinder body.

[0065] The above shows and describes the basic principle, main features and advantages of the utility model. Those skilled in the art should understand that the utility model is not limited by the above embodiments. The above embodiments and descriptions are only for explaining the principle of the utility model. Without departing from the spirit and scope of the utility model, the utility model may have various changes and improvements, which fall within the scope of the utility model to be protected. The scope of protection of the utility model is defined by the attached claims and their equivalents.

Claims

1. An engine balance shaft assembly, characterized in that: It includes a balancing shaft, a balancing block assembly, a first bearing assembly, a second bearing assembly, and a driving gear. The balancing block assembly is arranged on the surface of the balancing shaft body. The balancing block assembly and the balancing shaft are an integrated structure. The first bearing assembly and the second bearing assembly are respectively pressed on both sides of the balancing shaft. The driving gear is pressed on the balancing shaft and is located on the outside of the second bearing assembly.

2. The engine balance shaft assembly according to claim 1, characterized in that: The balancing shaft is an integrally formed structure, comprising a shaft body, a first mounting boss, a second mounting boss and a third mounting boss; The first mounting boss is provided at one end of the shaft body and is used for mounting the first bearing assembly; The two ends of the second mounting boss are respectively connected to the other end of the shaft body and one end of the third mounting boss. The second mounting boss is used to install the second bearing assembly, and the third mounting boss is used to install the driving gear.

3. The engine balance shaft assembly according to claim 2, characterized in that: The outer peripheral surface of the first mounting boss is provided with a mounting groove, in which the retaining ring can be installed, and a first annular limit platform is provided at the connection between the first mounting boss and the shaft body; The retaining ring is located on the outside of the first bearing assembly, and the first annular limiting platform is located on the inside of the first bearing assembly. The retaining ring and the first annular limiting platform cooperate to limit the position of the first bearing assembly.

4. The engine balance shaft assembly according to claim 2, characterized in that: The second mounting boss is coaxially distributed with the third mounting boss, and the diameter of the second mounting boss is larger than that of the third mounting boss. A step surface can be formed between the second mounting boss and the third mounting boss.

5. The engine balance shaft assembly according to claim 2, characterized in that: A second annular limiting platform is provided at the connection between the second mounting boss and the shaft body, the second annular limiting platform abuts against the second bearing assembly, and the second annular limiting platform limits the position of the second bearing assembly on the second mounting boss.

6. The engine balance shaft assembly according to claim 2, characterized in that: The outer ring of the first bearing assembly and the external mounting hole adopt interference fit, and the inner ring and the first mounting boss are press-fitted and transition fit is adopted.

7. The engine balance shaft assembly according to claim 2, characterized in that: An interference fit is adopted between the inner ring of the second bearing assembly and the second mounting boss, and between the driving gear and the third mounting boss, and a transition fit is adopted between the outer ring of the second bearing assembly and the external mounting hole.

8. The engine balance shaft assembly according to claim 1, characterized in that: The first bearing assembly and the second bearing assembly both use ball bearings.

9. The engine balance shaft assembly according to claim 2, characterized in that: The balancing weight assembly includes a plurality of balancing weights, and the plurality of balancing weights are integrally formed on the outer peripheral surface of the shaft body.

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