CN111365409A

CN111365409A - Engine and balance shaft thereof

Info

Publication number: CN111365409A
Application number: CN202010333192.3A
Authority: CN
Inventors: 王涛远; 尚丹鸽; 孙晓慧
Original assignee: QINGDAO DESHENG MACHINE MANUFACTURE CO Ltd
Current assignee: QINGDAO DESHENG MACHINE MANUFACTURE CO Ltd
Priority date: 2020-04-24
Filing date: 2020-04-24
Publication date: 2020-07-03

Abstract

The invention discloses a balance shaft of an engine, which comprises a balance shaft body (1), wherein the balance shaft body (1) is provided with a shaft neck, and is characterized in that the middle part of the shaft neck (2) protrudes outwards smoothly to form a bulge (3), and the height (h) of the bulge (3) is not more than the deformation of the shaft neck (2) which deforms inwards under stress. By applying the balance shaft of the engine provided by the invention, as the middle part of the shaft neck (2) of the balance shaft body (1) is provided with the bulge (3), the profile of the shaft neck (2) is inwards concave under the action of force in the middle of the shaft neck (2) in the running process of the engine. The deformation of the inward recess enables the profile of the journal (2) to tend to be straight, so that the journal can be better matched with the bearing bush, and the uniform gap between the whole journal (2) and the bearing bush is ensured, thereby reducing the abrasion between the journal (2) and the bearing bush and prolonging the service life of the bearing bush and the balance shaft. The invention also discloses an engine with the balance shaft, and the engine also has the technical effects.

Description

Engine and balance shaft thereof

Technical Field

The invention relates to the technical field of power machinery, in particular to a balance shaft of an engine and the engine.

Background

With the development of industrial technology, automobiles, motorcycles and the like become indispensable tools for human life, leisure and entertainment, engines in the automobiles and the motorcycles play a crucial role, and a balance shaft is a key component in the engine, so that the high quality of the balance shaft can ensure the efficient operation of the engine, and the abrasion condition of a shaft neck and a bearing bush of the balance shaft is crucial to the service life of the engine and the safety of the engine.

Referring to fig. 1-2, fig. 1 is a schematic structural diagram of a conventional balance shaft in the prior art; fig. 2 is an enlarged view of the journal profile of fig. 1. In the prior art, the surface of a shaft neck 2 of a balance shaft body 1 is straight, and when an engine runs, the middle of the shaft neck is stressed, so that the contour of the shaft neck is from straight to concave, the abrasion of a bearing bush is aggravated, and the service life of the bearing bush is shortened.

In summary, how to effectively solve the problems of short service life of the bearing bush caused by serious abrasion between the journal of the balance shaft and the bearing bush is a problem to be solved by those skilled in the art.

Disclosure of Invention

In view of the above, a first object of the present invention is to provide a balance shaft of an engine, which has a structural design that can effectively solve the problem that the journal of the balance shaft and the bearing bush are seriously worn to cause short service life of the bearing bush, and a second object of the present invention is to provide an engine including the balance shaft.

In order to achieve the first object, the invention provides the following technical scheme:

the balance shaft of the engine comprises a balance shaft body, wherein the balance shaft body is provided with a shaft neck, the middle part of the shaft neck is outwards and smoothly protruded to form a protrusion, and the height of the protrusion is not more than the deformation of the shaft neck which is inwards deformed under the stress.

Preferably, in the balance shaft of the engine described above, the height of the projection is not more than 0.006 mm.

Preferably, in the balance shaft of the engine, the height of the protrusion ranges from 0.002 mm to 0.006 mm.

Preferably, in the balance shaft of the engine, a surface of the protrusion is curved.

Preferably, in the balance shaft of the engine, the height of the protrusion gradually increases from the left and right side edges to the middle.

Preferably, in the balance shaft of the engine, the projection is symmetrical to the left and right about a center line of the journal.

The balance shaft of the engine comprises a balance shaft body, wherein the balance shaft body is provided with a shaft neck, the middle part of the shaft neck protrudes outwards smoothly to form a protrusion, and the height of the protrusion is not more than the deformation of the shaft neck which deforms inwards under stress.

By applying the balance shaft of the engine provided by the invention, because the middle part of the shaft neck of the balance shaft body is provided with the bulge, the shaft neck contour is inwards concave under the stress in the middle of the shaft neck in the running process of the engine. The inward-concave deformation enables the profile of the journal to tend to be straight, so that the journal can be better matched with the bearing bush, the uniform gap between the whole journal and the bearing bush is ensured, the abrasion between the journal and the bearing bush is reduced, and the service lives of the bearing bush and the balance shaft are prolonged.

In order to achieve the second object, the present invention also provides an engine including any one of the balance shafts described above. Since the above-mentioned balance shaft has the above-mentioned technical effects, the engine having the balance shaft should also have corresponding technical effects.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts.

FIG. 1 is a schematic structural view of a conventional balance shaft in the prior art;

FIG. 2 is an enlarged view of the journal profile of FIG. 1;

FIG. 3 is a schematic structural diagram of a balance shaft according to an embodiment of the present invention;

FIG. 4 is an enlarged view of the journal profile of FIG. 3;

FIG. 5 is a schematic view of the journal after being stressed.

The drawings are numbered as follows:

balance shaft body 1, journal 2, protrusion 3, protruding height h.

Detailed Description

The embodiment of the invention discloses an engine and a balance shaft thereof, which are used for reducing the abrasion of a shaft neck and a bearing bush and prolonging the service life.

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Referring to fig. 3-4, fig. 3 is a schematic structural diagram of a balance shaft according to an embodiment of the invention; FIG. 4 is an enlarged view of the journal profile of FIG. 3.

In one embodiment, the present invention provides a balance shaft of an engine including a balance shaft body 1.

When the engine is in operation, the piston moves very quickly and at a very non-uniform rate. When the piston is located at the upper and lower dead center positions, the speed is zero, but the speed at the middle position of the upper and lower dead center positions is highest. Because the piston makes repeated high-speed linear motion in the cylinder, large inertia force is inevitably generated on the piston, the piston pin and the connecting rod. While the counterweights on the connecting rods can effectively balance these inertial forces, only a portion of the moving mass participates in linear motion and another portion participates in rotation. Therefore, the inertia forces other than the top and bottom dead center positions cannot be completely balanced, and the engine vibrates.

To eliminate such vibration, the arrangement of a balance shaft is added. The balance shaft is a shaft which is provided with an eccentric weight and rotates synchronously with the crankshaft, and the engine obtains good balance effect and reduces the vibration of the engine by utilizing the reverse vibration force generated by the eccentric weight. The balance shaft body 1 is a main structure of the balance shaft, and for a specific structure, reference is made to the arrangement of a conventional balance shaft in the prior art, which is not described herein again. The balance shaft body 1 has a shaft neck, and the present application mainly aims at the shaft neck 2 of the balance shaft body 1, and the abrasion of the shaft neck 2 and a bearing bush is reduced through the structural improvement, so the following description focuses on the structure of the shaft neck 2 of the balance shaft body 1.

The middle of the journal 2 protrudes smoothly outward to form a projection 3. It should be noted that the middle portion herein refers to the middle portion of the journal 2 except for the two ends, and is not limited to the center line. The bulge 3 is formed by the shaft neck 2 protruding outwards smoothly, which means that the contour of the shaft neck 2 with the bulge 3 is smooth overall, and the bulge 3 is not provided with edges and corners. Here and in the following, the outer refers to the radial direction outwards of the journal 2.

The height h of the bulge 3 is not larger than the deformation amount of the journal 2 deformed inwards under force, and the contour of the journal 2 is concave inwards due to the force applied to the middle of the journal 2 in the running process of the engine. Through setting up the height h of protruding 3 and being not more than the deflection of 2 atress inward deformation of axle journal, if in the engine operation process, 2 middle atress of axle journal makes axle journal 2 profile indent 0.003mm, then protruding 3 height h is not more than 0.003mm to in the engine operation process, the height that the axle journal 2 profile indent offsets with protruding 3 height h, makes the profile of axle journal 2 more tend to straight. And the height h of the bulge 3 is not more than the deformation of the journal 2 deformed inwards under stress, so that the problem that the journal 2 still has the bulge 3 to aggravate the abrasion with the bearing bush in the running process of the engine is avoided.

As shown in fig. 5, fig. 5 is a schematic structural view of the journal 2 after being stressed. In fig. 5, the broken line shows the profile of the journal 2 before deformation, the solid line shows the profile after deformation, and the arrows show the force direction. It can be seen that by the provision of the projection 3, the middle of the journal 2 is deformed and straightened during engine operation.

In summary, according to the balance shaft of the engine provided by the invention, since the middle of the journal 2 of the balance shaft body 1 is provided with the protrusion 3, during the operation of the engine, the middle of the journal 2 is stressed, so that the contour of the journal 2 is concave. The inward-concave deformation enables the profile of the journal 2 to tend to be straight, so that the journal 2 can be better matched with the bearing bush, and the uniform gap between the whole journal 2 and the bearing bush is ensured, so that the abrasion between the journal 2 and the bearing bush is reduced, and the service lives of the bearing bush and the balance shaft are prolonged.

Specifically, the height h of the projection 3 is not more than 0.006 mm. Generally speaking, when the engine runs, the middle of the shaft neck 2 is stressed, so that the height of the inward concave fishtail of the shaft neck 2 is 0.006mm, and therefore, the height h of the protrusion 3 is set to be less than or equal to 0.006mm, and the height of the inward concave fishtail of the shaft neck 2 can be well offset in the running process of the engine.

Preferably, the height h of the protrusion 3 is in the range of 0.002-0.006 mm. Of course, for a certain balance shaft, the height h of the projection 3 of the journal 2 should be a certain value, and the value is within the above numerical range. It should be noted that the height h of the projection 3 refers to the distance between the highest point of the projection 3 and the lowest point of the contour of the journal 2.

In the above embodiments, the surface of the protrusion 3 is curved. The curved surface structure has guaranteed that protruding 3 surfaces do not have edges and corners, has avoided edges and corners and axle bush contact to cause the aggravation of wearing and tearing. And through the curved surface arrangement, stress concentration is avoided, and the deformation of the shaft neck 2 is better adapted in the running process of the engine. The shape of the specific curved surface can be set according to the requirement, such as an arc surface.

Further, the height h of the protrusion 3 gradually increases from the left and right side edges to the middle. Since the journal 2 is stressed at an intermediate position during engine operation, the intermediate corresponding amount of deformation of the journal 2 is large. The height h of the protrusion 3 is gradually increased from the edges of the left side and the right side to the middle, so that the deformation of the journal 2 in the running process of an engine can be better counteracted, namely, the position with the larger middle height counteracts the larger inward concave deformation in the middle of the journal 2, and the positions with the smaller heights of the two sides counteract the smaller inward concave deformation of the journal 2.

Specifically, the projection 3 is bilaterally symmetric about the centerline of the journal 2. I.e. the shape of the projection 3 satisfies bilateral symmetry about the centre line of the journal 2. In the running process of the engine, the middle of the journal 2 is stressed, and the inward concave deformation is generally bilaterally symmetrical about the center line, so that the protrusion 3 is correspondingly arranged into a bilaterally symmetrical structure, the journal 2 is stressed and straightened in the middle of the running process of the engine, the uniform gap between the whole journal and the bearing bush is further ensured, the abrasion between the journal and the bearing bush is reduced, and the service lives of the journal 2 and the bearing bush are prolonged.

Based on the balance shaft provided in the above embodiment, the invention further provides an engine, which includes any one of the balance shafts in the above embodiments. Since the engine adopts the balance shaft in the above embodiment, please refer to the above embodiment for the beneficial effect of the engine.

The embodiments in the present description are described in a progressive manner, each embodiment focuses on differences from other embodiments, and the same and similar parts among the embodiments are referred to each other.

The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. The balance shaft of the engine comprises a balance shaft body (1), wherein the balance shaft body (1) is provided with a shaft neck, and is characterized in that the middle of the shaft neck (2) protrudes outwards smoothly to form a bulge (3), and the height (h) of the bulge (3) is not greater than the deformation of the shaft neck (2) deformed inwards under stress.

2. The balance shaft of the engine according to claim 1, wherein the height (h) of the protrusion (3) is not more than 0.006 mm.

3. The balance shaft of an engine according to claim 1, wherein the height (h) of the protrusion (3) is in the range of 0.002 to 0.006 mm.

4. Balance shaft for an engine according to any of claims 1-3, characterized in that the surface of the protrusion (3) is curved.

5. The balance shaft of an engine according to claim 4, wherein the height (h) of the protrusion (3) is gradually increased from the left and right side edges to the middle.

6. The balance shaft of an engine according to claim 5, wherein the projection (3) is left-right symmetrical about a centerline of the journal (2).

7. An engine comprising a balance shaft according to any of claims 1 to 6.