JP2014142019A - Thrust bearing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a thrust bearing capable of preventing contact pressure of a sliding surface from becoming excessive while effectively supplying more lubricating oil between a crank arm and the sliding surface.SOLUTION: A thrust bearing 7 comprises a sliding surface 11 sliding on a crank arm 2c of a crankshaft 2, and an oil groove 12 formed to cross the sliding surface in an almost radial direction. The oil groove is formed of a bottom face 12a, an upstream side wall face 12b situated on an upstream side with respect to a rotation direction of the crankshaft, and a downstream side wall face 12c situated on a downstream side. An inclination angle α of the upstream side wall face to the bottom face is set larger than an inclination angle β of the downstream side wall face to the bottom face.

Description

  The present invention relates to a thrust bearing, and more particularly, to a thrust bearing having an oil groove formed so as to intersect a sliding surface in a substantially radial direction.

Conventionally, in an engine such as an automobile, a journal of a crankshaft is pivotally supported by a housing formed in a cylinder block and a cap fixed to the housing, and the side surface of the housing slides on a crank arm of the crankshaft. A thrust bearing made of a circular arc member in contact therewith is provided (Patent Document 1).
The thrust bearing is formed with a sliding surface that slides with the crank arm of the crankshaft, and an oil groove is provided on the sliding surface so as to intersect substantially the radial direction.
Lubricating oil is supplied to the oil groove from the outside, and the lubricating oil inside the oil groove is drawn between the crank arm and the sliding surface by rotating the crankshaft so as to lubricate them. It has become.

JP-A-11-2011145

Here, it is required to efficiently supply lubricating oil between the crank arm and the sliding surface to prevent seizure, and as an example, the inclination angle of the wall surface forming the oil groove is small, That is, it can be considered to lay down.
However, if the inclination angle of the wall surface is reduced, the contact area between the sliding surface and the crank arm is reduced, and the surface pressure acting on the sliding surface becomes excessive and seizure occurs. There is a fear.
In view of these problems, the present invention provides a thrust bearing capable of efficiently supplying lubricating oil between the crank arm and the sliding surface while preventing the surface pressure of the sliding surface from becoming excessive. Is to provide.

That is, the thrust bearing according to the present invention is a member having an arc shape, and is formed so that the sliding surface sliding with the crank arm of the crankshaft intersects the sliding surface in a substantially radial direction. In thrust bearings with oil grooves,
The oil groove is composed of a bottom surface, an upstream side wall surface located on the upstream side with respect to the rotation direction of the crankshaft, and a downstream side wall surface located on the downstream side,
An inclination angle α with respect to the bottom surface of the upstream side wall surface is set to be larger than an inclination angle β with respect to the bottom surface of the downstream side wall surface.

According to the above invention, the crank arm and the sliding member are moved from the downstream side wall surface having a small inclination angle by setting the inclination angle α of the upstream side wall surface in the oil groove to be larger than the inclination angle β of the downstream side wall surface. Lubricating oil can be efficiently supplied between the surfaces.
On the other hand, by increasing the inclination angle α of the upstream side wall surface, the contact area between the sliding surface and the crank arm can be secured, and the surface pressure acting on the sliding surface can be prevented from becoming excessive. it can.

Sectional drawing which shows the internal structure of an engine. The figure which looked at FIG. 1 from the direction of II-II part. Sectional drawing of the III-III part of FIG. Sectional drawing which shows 2nd Example.

FIG. 1 shows the internal structure of an engine 1, and shows a crankshaft 2, a housing 3 formed on a cylinder block and supporting the crankshaft 2, and a connecting rod connected to a piston (not shown). 4.
The crankshaft 2 is connected with a plurality of journals 2a pivotally supported by the housing 3, a plurality of crankpins 2b rotatably connected to the connecting rod 4, and the journals 2a and the crankpins 2b being eccentrically connected. The crank arm 2c to hold is comprised.
The crankshaft 2 is pivotally supported by a main bearing 5 comprising two halved main bearings. The main bearing 5 is held on the housing 3 by a cap 6, and the cap 6 is fastened to the housing 3 by a bolt (not shown). Yes.
Further, annular recesses 3a are formed on the side surfaces of both sides in the axial direction of the housing 3 along the inner peripheral surface that accommodates the main bearing 5, and each of the annular recesses 3a is a thrust made of an arcuate member. A bearing 7 is provided.
The thrust bearing 7 slides with the crank arm 2c while receiving a load in the thrust direction between the housing 3 and the crank arm 2c when the crankshaft 2 rotates and moves in the axial direction due to clutch engagement and the like. It is like that.
In particular, in this embodiment, the crankshaft 2 moves from the right to the left in FIG. 1 to apply a load, that is, the right side of the two thrust bearings 7 is illustrated. A larger load is applied to the thrust bearing 7 than the thrust bearing 7 on the left side of the figure.

Hereinafter, the thrust bearing 7 will be described with reference to FIGS. Here, FIG. 2 shows a view of FIG. 1 as viewed from the direction of II-II.
The thrust bearing 7 is a flat plate-like member having an arc shape. The thrust bearing 7 is formed to a position where the end coincides with the lower end of the housing 3 and is in contact with the cap 6.
One surface of the thrust bearing 7 is formed with a sliding surface 11 that is in sliding contact with the crank arm 2c, and the other surface is formed with a contact surface (not shown) that contacts the housing 3.
Among these, the sliding surface 11 is provided with oil grooves 12 formed so as to intersect the radial direction of the thrust bearing 7 at two locations, and is supplied between the journal 2 a and the main bearing 5. The lubricating oil is supplied between the sliding surface 11 of the thrust bearing 7 and the crank arm 2c.
Further, at both ends of the sliding surface 11, thrust reliefs 11a inclined so as to gradually become thinner are provided.

FIG. 3 shows a cross-sectional view of the oil groove 12 at the position of the III-III portion in FIG. The other oil groove 12 has the same cross-sectional shape, and detailed description thereof is omitted.
In FIG. 3, the crank arm 2 c slides from the left to the right in the drawing with respect to the sliding surface 11 by the rotation of the crankshaft 2. The groove 12 includes a bottom surface 12a, an upstream side wall surface 12b located on the upstream side with respect to the rotation direction of the crankshaft 2, and a downstream side wall surface 12c located on the downstream side.
In this embodiment, the inclination angle α of the upstream side wall surface 12b with respect to the bottom surface 12a is set larger than the inclination angle β of the downstream side wall surface 12c with respect to the bottom surface 12a, in other words, the upstream side wall surface 12b. It becomes the structure which lays down the downstream side wall surface 12c rather than.
Specifically, the inclination angle β of the downstream side wall surface 12c is set to a range of 15 ° to 60 °, and the relationship between the inclination angle α of the upstream side wall surface 12b and the inclination angle β of the downstream side wall surface 12c is expressed as follows: It is desirable to set a range.
(Α−β) ≧ 15 ° (Formula 1)
More desirably, the inclination angle β of the downstream side wall surface 12c is in the range of 30 ° to 45 °, and the equation 1 is satisfied, the inclination angle α of the upstream side wall surface 12b is set to 60 ° to 90 °. If set in this range, the effects described later can be obtained more effectively.

The following effects are acquired by using the thrust bearing 7 which has the said structure.
When the crankshaft 2 rotates and the crank arm 2c slides on the sliding surface 11 of the thrust bearing 7, the lubricating oil supplied between the journal 2a and the main bearing 5 is inside the oil groove 12. To be supplied.
In FIG. 3, the crank arm 2c is moved from the left to the right in the drawing, and the lubricating oil inside the oil groove 12 flows between the crank arm 2c and the sliding surface 11 from the downstream side wall surface 12c side. They are drawn into and lubricate these.
At this time, since the inclination angle α of the upstream side wall surface 12b is set larger than the inclination angle β of the downstream side wall surface 12c, the downstream side wall surface 12c is laid down. The lubricating oil is drawn in satisfactorily, whereby the crank arm 2c and the sliding surface 11 can be lubricated satisfactorily.
Here, in the thrust bearing 7 on the right side in FIG. 1, that is, the thrust bearing 7 that receives a large load due to the movement of the crankshaft 2, if the wall surface of the oil groove 12 is excessively laid, the sliding surface 11 and the crank Since the contact area with the arm 2c is narrowed, the surface pressure on the sliding surface 11 becomes excessive, which may cause seizure or the like.
Therefore, in this embodiment, the upstream side wall surface 12b is made to stand up by setting the inclination angle α of the upstream side wall surface 12b to be larger than the inclination angle β of the downstream side wall surface 12c. The sliding surface 11 is secured in the vicinity of the upstream side wall surface 12b, so that the surface pressure acting on the entire sliding surface 11 does not become excessive.

On the other hand, the thrust bearing 7 provided on the left side in FIG. 1 has the same shape as the thrust bearing 7 provided on the right side in the figure, and in the state shown in FIG. On the other hand, it slides from the right to the left in the figure.
For this reason, the positional relationship between the upstream side wall surface 12b and the downstream side wall surface 12c is opposite to that of the thrust bearing 7 located on the right side in the figure, and the inclination angle of the upstream side wall surface becomes smaller than the inclination angle of the downstream side wall surface.
As a result, an event opposite to the above effect, that is, the downstream side wall surface (upstream side wall surface 12b in FIG. 3) stands up, leading to poor drawing of the lubricating oil from the oil groove 12, and the upstream side wall surface (in FIG. 3). The contact area with the crank arm 2c is narrowed because the downstream side wall surface 12c) lies down.
However, since the load acts on the crankshaft 2 from the right to the left in the drawing in FIG. 1, the load acting on the left thrust bearing 7 in the drawing is lower than the load acting on the right thrust bearing 7 in the drawing, Insufficient lubricating oil and seizure due to excessive surface pressure are less likely to occur.
On the other hand, since the thrust bearing 7 having the same shape can be mounted on the left side and the right side of the housing 3 in FIG. 1, the types of components of the engine 1 can be suppressed, and the assembly of the engine 1 is possible. It is possible to prevent a mounting mistake at the time.

FIG. 4 shows a sectional view of the oil groove 12 according to the second embodiment, and shows a sectional view at the same position as FIG. In the present embodiment, detailed description of the configuration common to the first embodiment is omitted.
In this embodiment, a coating C made of a solid lubricant or a fluorine resin is formed on the surface of the sliding surface 11, and the coating C is formed after the oil groove 12 is cut on the surface of the sliding surface 11. It is supposed to be formed.
And when forming the said coating C, the said coating C is formed in the middle of the upstream side wall surface 12b and the downstream side wall surface 12c in the said oil groove 12, and the said coating C is made not to reach the bottom face 12a.
In the present embodiment, the inclination angle α of the upstream side wall surface 12b and the inclination angle β of the downstream side wall surface 12c are the boundary between the upstream side wall surface 12b and the bottom surface 12a of the downstream side wall surface 12c, and the top of the coating C. It can be set according to how much the line connecting the two is inclined with respect to the bottom surface 12a.
According to the thrust bearing 7 of the second embodiment, the lubricating oil is satisfactorily supplied between the sliding surface 11 and the crank arm 2c by laying the downstream side wall surface 12c, as in the first embodiment, and By raising the upstream side wall surface 12b, it is possible to secure a contact area between the sliding surface 11 and the crank arm 2c so that excessive surface pressure does not act.
Moreover, since the coating C is formed so as not to reach the bottom surface 12a, the depth of the oil groove 12 is not reduced by the coating C, and the accommodation amount of the lubricating oil by the oil groove 12 is not impaired. ing.

2 Crankshaft 2c Crank arm 7 Thrust bearing 11 Sliding surface 12 Oil groove 12a Bottom surface 12b Upstream side wall surface 12c Downstream side wall surface α Inclination angle of upstream side wall surface β Inclination angle of downstream side wall surface C Coating

Claims (4)

In a thrust bearing comprising an arc-shaped member, comprising: a sliding surface that slides with a crank arm of the crankshaft; and an oil groove that is formed to intersect the sliding surface in a substantially radial direction.
The oil groove is composed of a bottom surface, an upstream side wall surface located on the upstream side with respect to the rotation direction of the crankshaft, and a downstream side wall surface located on the downstream side,
A thrust bearing, wherein an inclination angle α of the upstream side wall surface with respect to the bottom surface is set larger than an inclination angle β of the downstream side wall surface with respect to the bottom surface.   The thrust bearing according to claim 1, wherein an inclination angle β of the downstream side wall surface is set in a range of 15 ° to 60 °. The inclination angle α of the upstream side wall surface and the inclination angle β of the downstream side wall surface,
(Α−β) ≧ 15 ° (Formula 1)
The thrust bearing according to claim 1, wherein the thrust bearing is set in accordance with the following relationship.   4. The coating according to claim 1, wherein a coating is formed on a surface of the sliding surface, and the coating is formed partway along the upstream side wall surface and the downstream side wall surface in the oil groove. Thrust bearings.

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