JPH0510391A - Bearing device for balancer shaft - Google Patents

Abstract

PURPOSE:To improve strength without deteriorating the machinability and workability at the time of assembling. CONSTITUTION:A cylindrical flat bearing section 31 and a circular flange section expanded in the radial direction from its base end are integrally formed with a bearing metal 1 respectively. A notch is formed on the flange section, and a projection to be coupled with the notch to stop the rotation of the bearing metal 1 is formed on the side wall of a bearing housing 21. Inner diameters D1-D3 of bearing housings 21-23 are made smaller in steps, and outer diameters D42, D43, of flange sections 42, 43 of bearing metals 2, 3 are made smaller than the inner diameters D1, D2 of the bearing housings 21, 22 located on the base end side respectively. A thrust reception section expanded to the inside in the radial direction from the tip of the flat bearing section 31 and brought into contact with the thrust reception face of a balancer shaft is formed integrally with the bearing metal inserted between a tip side journal section and the bearing housing 23.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bearing device for a balancer shaft provided in an engine.

[0002]

2. Description of the Related Art Conventionally, in order to suppress the secondary vibration of a reciprocating engine, there has been one in which a balancer shaft having an eccentric mass portion is rotated in synchronization with the engine rotation.

The bearing device of the balancer shaft receives a centrifugal force of the eccentric mass part against the engine block, and therefore the balancer shaft is provided with a plurality of journal parts, and each journal part is provided with a bearing metal (plain bearing) through the engine block. Is rotatably supported (see, for example, Japanese Utility Model Laid-Open No. 62-136648).

[0004]

However, in such a conventional device, in order to prevent rotation of the cylindrical bearing metal, a notch is formed on the back side of the bearing metal and the notch is formed on the engine block side. Has a pawl (projection) that engages with this notch, so there is a possibility that the bearing metal may be crushed and deformed due to the load that accompanies thermal deformation of the engine block or flexural deformation of the balancer shaft. Moreover, workability was deteriorated.

In view of the above points, the present invention aims to increase the strength of a bearing device without deteriorating workability and workability during assembly.

[0006]

According to the present invention, an eccentric mass part and a plurality of journal parts are provided on a balancer shaft that rotates in synchronization with engine rotation, and each journal part is rotated on the engine block side through a bearing metal. In a bearing device for a balancer shaft in which a bearing housing that freely supports is formed, each bearing metal is integrally formed with a cylindrical flat bearing portion and an annular flange portion that extends radially from the base end of the flat bearing portion. Then, while forming a notch in the flange portion, a protrusion is formed in the side wall of the bearing housing to engage with the notch and prevent the bearing metal from rotating.

Further, the inner diameter of each bearing housing is gradually reduced from the base end side to the tip end side of the balancer shaft, and the outer diameter of the flange portion of each bearing metal is smaller than the inner diameter of the bearing housing located on the base end side. Form small.

In addition, a thrust receiving surface is formed at the tip of the balancer shaft, and a bearing metal interposed between the tip side journal portion and the bearing housing is provided with a flange portion that extends radially outward from the base end of the plain bearing portion. , A thrust bearing portion that extends radially inward from the tip of the flat bearing portion and that makes sliding contact with the thrust bearing surface is integrally formed.

[0009]

In the balancer shaft, the respective journals are rotatably fitted to the bearing housing via the bearing metal, so that the load in the radial direction is supported. The notch formed in the flange portion engages with the protrusion formed on the side wall of the bearing housing to prevent the bearing metal from rotating.

Since each bearing metal has an L-shaped cross section due to the flange portion, its rigidity is enhanced, and the bearing metal is crushed and deformed due to thermal deformation of the bearing housing and flexural deformation of the balancer shaft. It can be prevented.

Further, by forming the notch for performing the rotation stopping function in the flange portion, the rigidity of the bearing metal is increased by the notch as compared with the case where the notch is formed on the outer periphery of the bearing metal as in the conventional device. It is possible to prevent the deterioration and to improve the workability of the notch.

Further, since the inner diameters of the bearing housings are gradually reduced so that the front bearing housing can be inserted when the bearing metals are assembled, the bearing metals can be assembled simultaneously through a jig. It is possible to attach it, and the assembling work can be simplified.

Further, while the thrust receiving surface is formed at the tip of the balancer shaft, the bearing receiving metal is provided with the thrust receiving portion which extends radially inward from the tip of the plain bearing portion and makes sliding contact with the thrust receiving surface. The bearing metal supports the load in the thrust direction, which tends to move the balancer shaft toward the tip side, and simplifies the structure.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS As shown in FIG.
Eccentric mass part 10 and three journal parts 11, 12, 1
3 and 3. The cylinder block 8 is formed with bearing housings 21, 22 and 23 into which the journal portions 11, 12 and 13 are rotatably fitted through the bearing metals 1, 2 and 3, respectively. As a result, the balancer shaft 9 is supported in the radial direction.

The balancer shaft 9 has thrust receiving surfaces 14 and 15 formed in the middle thereof so as to face each other, and
The cylinder block 8 is provided with a thrust bearing member 7 slidably fitted between the thrust receiving surfaces 14 and 15 of the bolt 2
It is fastened by 9. As a result, the balancer shaft 9
Is supported in the thrust direction.

The balancer shaft 9 has its base end (front end).
The drive pulley 6 is attached to the tip of the shaft portion 16 formed in the above through a bolt 28, and a belt (not shown) is wound around between the pulley 6 and the crank pulley. As a result, the balancer shaft 9 is rotationally driven at a speed twice that of the crankshaft. In addition, the pulley 6 is the shaft portion 16
It is fastened via a washer 27 by a bolt 28 that is screwed into. A key 26 is interposed between the pulley 6 and the shaft portion 16. A seal member 25 is interposed between the shaft portion 16 and the front case 5 penetrating the shaft portion 16.

The bearing metals 1, 2, 3 are cylindrical flat bearing portions 31, 32 interposed between the bearing housings 21, 22, 23 of the cylinder block 8 and the journal portions 11, 12, 13, respectively. , 33 and flange portions 41, 42, 43 having an L-shaped cross section and annularly expanding from the base ends of the respective plain bearing portions 31, 32, 33.

The inner diameter D ₁ of the bearing housing 21 into which the proximal end side journal portion 11 is fitted via the bearing metal 1 is larger than the outer diameter D ₄₂ of the flange portion 42 of the central bearing metal 2. The inner diameter D ₂ of the bearing housing 22 into which the central journal portion 12 is fitted via the bearing metal 2 is
It is formed to be larger than the outer diameter D ₄₃ of the flange portion 43 of the bearing metal 3 at the rear end. Of course, the outer diameter D ₄₁ of the flange portion 41 of the base end bearing metal 1 is the inner diameter D _{1 of the} bearing housing 21.
It is formed larger. The inner diameter D ₃ of the bearing housing 23 into which the tip journal portion 13 is fitted via the bearing metal 3 is made smaller, and D ₁ > D ₂ > D ₃ and D ₄₁ > D ₁ > D ₄₁ , D ₂ >. It has a relationship of D ₄₃ .

As shown in FIGS. 2, 3 and 4, two notches 18 are formed in the flange 41 of the bearing metal 1.
19 is formed, and a protrusion 17 that engages with the one notch 18 is formed on the side wall 34 of the bearing housing 21 to prevent the bearing metal 1 from rotating. The protrusion 17 has a circular cross section, and the notch 18 is formed in a semicircular shape. Similarly, two notches are formed in each of the flange portions 42 and 43 of the other bearing metals 2 and 3, and a protrusion that engages with one of the notches is formed in the bearing housings 22 and 23, respectively. Then, the rotation is stopped.

When assembling the bearing metals 1, 2 and 3, as shown in FIG. 5, a jig 39 for fitting the bearing metals 1, 2 and 3 respectively is used. The jig 39 is an annular step portion 35, 36, 3 on which the bearing metals 1, 2, 3 are seated.
7, each annular step 35, 36, 37 has a protrusion 45, 46, which engages with the notch 19 of each bearing metal 1, 2, 3.
47 are formed so as to project, and both are positioned. A guide hole 48 is formed in the bearing housing 21 at the tip, and a guide hole 49 is formed in the jig 39. The guide rod 50 is inserted into each of the guide holes 48, 49, and the cylinder block 8 is inserted. The jig 39 is positioned.

Next, the operation will be described.

The balancer shaft 9 is provided in each journal portion 1
1, 12 and 13 are rotatably fitted to the bearing housings 21, 22 and 23 via the bearing metals 1, 2 and 3 to support the load in the radial direction, and the eccentric mass portion 1
The secondary vibration of the engine is canceled by the centrifugal force of 0. By engaging the notches 18 and the like formed in the flange portions 41, 42, and 43 with the protrusions 17 and the like formed on the side walls 34 and the like of the bearing housings 21, 22, and 23,
The bearing metals 1, 2, 3 are prevented from rotating.

Each bearing metal 1, 2, 3 has an L-shaped cross section by the respective flange portions 41, 42, 43 to increase its rigidity, and each bearing housing 21,
It is possible to prevent the bearing metals 1, 2 and 3 from being crushed and deformed due to thermal deformation of 22 and 23 and flexural deformation of the balancer shaft 9.

Further, the notch 18 which serves as a rotation stopping function.
By forming the notch on the flange portion 41, the rigidity of the bearing metal is not significantly reduced by the notch 18 as compared with the case where the notch is formed on the outer circumference of the bearing metal as in the conventional device, and the notch 18 has Workability can be improved.

Further, each bearing housing 21, 22, 23
The inner diameters of the bearings are made smaller stepwise in the relationship of D ₁ > D ₂ > D ₃ , and when the bearing metals 2 and 3 are assembled, the front bearing housings 21 and 22 can be inserted respectively. The bearing metals 1, 2, and 3 can be assembled at the same time via the jig 39, and the assembling work can be simplified.

Next, another embodiment shown in FIG. 6 will be described.

The balancer shaft 51 has a thrust receiving surface 15 formed in the middle thereof, while the cylinder block 8
The thrust receiving member 7 that is in sliding contact with the thrust receiving surface 15 is fastened by a bolt 29. As a result, the load in the thrust direction that tends to move the balancer shaft 51 to the base end side is supported.

While the thrust receiving surface 52 is formed on the tip end surface of the balancer shaft 51, the tip end side journal portion 53 and the bearing housing 2 are also shown in FIGS. 7 and 8.
A flange portion 56 that extends radially outward from the base end of the flat bearing portion 55 and a thrust receiving surface 52 that extends radially inward from the tip end of the flat bearing portion 55 slide on the bearing metal 54 interposed between the three. The thrust receiving portions 57 to be brought into contact with each other are integrally formed. The thrust receiving surface 52 supports the load in the thrust direction that tends to move the balancer shaft 51 to the tip side, and the thrust receiving surface 1 in the above-described embodiment.
4 can be abolished, balancer shaft 51
The structure can be simplified and the workability can be improved.

[0029]

As described above, according to the present invention, in a bearing device for a balancer shaft, a cylindrical flat bearing portion is provided on each bearing metal, and an annular flange portion that extends radially from the base end of the flat bearing portion. To form a notch in the flange, while forming a protrusion on the side wall of the bearing housing to prevent the bearing metal from rotating by increasing the rigidity of the bearing metal. In addition, the workability of the notch in the bearing metal can be improved.

Further, the inner diameter of each bearing housing is formed so as to gradually decrease from the base end side to the tip end side of the balancer shaft, and the outer diameter of the flange portion of each bearing metal is smaller than the inner diameter of the bearing housing located on the base end side. By making it small, it becomes possible to assemble each bearing metal at the same time via a jig, and the assembling work can be greatly simplified.

Further, a thrust receiving surface is formed at the tip of the balancer shaft, and a bearing metal interposed between the tip side journal portion and the bearing housing is provided with a flange portion extending radially outward from the base end of the plain bearing portion. By integrally forming the thrust receiving portion that extends radially inward from the tip of the flat bearing portion and is in sliding contact with the thrust receiving surface, the support structure in the thrust direction can be simplified.

[Brief description of drawings]

FIG. 1 is a vertical sectional view showing an embodiment of the present invention.

FIG. 2 is a transverse sectional view of the same.

FIG. 3 is a front view of the bearing metal.

FIG. 4 is a vertical sectional view of the bearing metal.

FIG. 5 is a vertical sectional view of the same when assembled.

FIG. 6 is a vertical cross-sectional view showing another embodiment.

FIG. 7 is a front view of the bearing metal.

FIG. 8 is a vertical sectional view of the bearing metal.

[Explanation of symbols]

1 Bearing metal 2 Bearing metal 3 Bearing metal 8 cylinder block 9 Balancer shaft 11 Journal Department 12 Journal Department 13 Journal Department 17 Protrusion 18 notches 21 Bearing housing 22 Bearing housing 23 Bearing housing 31 plain bearing 32 plain bearing 33 Plain bearing 41 Flange 42 Flange 43 Flange 51 balancer shaft 52 Thrust receiving surface 53 Journal Department 54 Bearing metal 55 Plain bearing 56 Flange 57 Thrust receiving part

Claims (3)

[Claims] 1. A balancer shaft that rotates in synchronization with engine rotation is provided with an eccentric mass part and a plurality of journal parts,
In a bearing device for a balancer shaft, in which a bearing housing that rotatably supports each journal section via a bearing metal is formed on the engine block side, a cylindrical plain bearing section is provided on each bearing metal, and a base of this plain bearing section is provided. An annular flange that extends radially from the end is formed integrally with each other, and a notch is formed in this flange, while a protrusion that engages with this notch and prevents the bearing metal from rotating is formed on the side wall of the bearing housing. A bearing device for a balancer shaft, which is formed. 2. The inner diameter of each bearing housing is gradually reduced from the base end side to the tip end side of the balancer shaft, and the outer diameter of the flange portion of each bearing metal is smaller than the inner diameter of the bearing housing located on the base end side. The bearing device for a balancer shaft according to claim 1, wherein the bearing device is formed small. 3. A thrust bearing surface is formed at the tip of the balancer shaft, and a bearing metal interposed between the tip side journal portion and the bearing housing is provided with a flange portion extending radially outward from the base end of the plain bearing portion. 3. The balancer shaft bearing device according to claim 1, wherein the flat bearing portion is integrally formed with a thrust receiving portion that extends radially inward from the end of the flat bearing portion and contacts the thrust receiving surface.