JP2017207167A - Half-split thrust bearing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce a risk that lubrication between a crank and land parts becomes insufficient resulting from the fact that the amount of lubricants supplied between the crank and the land parts from tapered parts becomes insufficient, in a half-split thrust bearing for supporting a crankshaft.SOLUTION: A half-split thrust bearing 10 which extends around an axial line 12 in a semi-circular shape, and supports a crankshaft at one side face 14 facing a direction along the axial line has: a plurality of land parts 24 which are separately arranged in a peripheral direction, and slide-contact with the crankshaft; a plurality of tapered parts 26 which are located at a delay side of the crankshaft in a rotation direction with respect to the corresponding land parts, and whose heights are gradually increased up to the corresponding land parts; and a plurality of groove parts 28 which are located at a delay side in the rotation direction with respect to the corresponding tapered parts, and extend to a radial direction. One of a plurality of the groove parts is formed at an end part of the half-split thrust bearing 10 at a delay side in the rotation direction.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a half thrust bearing that supports a crankshaft.

  As a thrust bearing for supporting a crankshaft of an engine mounted on a vehicle such as an automobile, for example, as described in Patent Document 1 below, the crankshaft extends in a semicircular shape around an axis and is cranked on one side surface. A half thrust bearing that supports a shaft is known. The half thrust bearing is interposed between the crankshaft crank and an engine component such as a crankcase, and ensures that the crankshaft rotates smoothly with respect to the engine component while acting on the engine component from the crank. Support.

  Lubricating oil is also supplied between the crank and engine parts to prevent the crank and engine parts from sliding directly. In particular, in the half thrust bearing described in Patent Document 1, tapered portions whose height gradually increases toward the land portion on the center side from both ends in the circumferential direction are provided. Therefore, the lubricating oil between the crank portion on the delay side of the crank and the crank is moved in the rotation direction of the crank due to its viscosity and compressed between the taper and the crank. Gradually increases and a wedge oil film pressure is generated. Therefore, as compared with the case where the taper portion is not provided, the progress of wear of the land portion of the crank and the thrust bearing can be suppressed, and the friction loss of the engine can be reduced.

JP 2014-126199 A

[Problems to be Solved by the Invention]
However, particularly when a plurality of taper portions are provided, the circumferential length of the taper portion cannot be increased, and the gap between the surface of the taper portion and the crank cannot be increased. Therefore, since the amount of lubricating oil supplied to and retained by the tapered portion cannot be increased, the lubricating oil cannot be continuously supplied from the tapered portion to the crank and the land portion without interruption. Insufficient lubrication tends to be insufficient.

  The main problem of the present invention is that, in a half thrust bearing that supports a crankshaft, the amount of lubricating oil supplied from the taper portion to the space between the crank portion and the land portion becomes insufficient. This is to reduce the possibility of insufficient lubrication.

[Means for Solving the Problems and Effects of the Invention]
According to the present invention, a half thrust bearing (10) that extends in a semicircular arc around the axis (12) and supports the crankshaft (16) on one side surface (14) facing in the direction along the axis. ) Is provided.

  The thrust bearing (10) has a plurality of land portions (24) that are spaced apart in the circumferential direction and are in sliding contact with the crankshaft (16), and the corresponding land portions are positioned on the delay side in the rotation direction of the crankshaft. A plurality of taper portions (26) whose height gradually increases to a portion, and a plurality of groove portions (28) that are located on the rotation direction delay side with respect to the corresponding taper portions and extend across the circumferential direction. One of the plurality of grooves is provided at the end of the half thrust bearing (10) on the rotation direction delay side.

  According to said structure, the lubricating oil in a groove part is drawn in between a taper part and a crankshaft by the lubricating oil between a taper part and a crankshaft moving toward a land part. The supply of the lubricating oil to the groove and the movement of the lubricating oil from the groove portion to the taper portion and the crankshaft continuously occur while the crankshaft is rotating. Therefore, the amount of lubricating oil supplied between the land portion and the crankshaft is insufficient compared to the case of the conventional thrust bearing in which the groove portion is not provided at the end of the thrust bearing on the rotation direction delay side. This can reduce the risk of insufficient lubrication between them.

  In the above description, in order to help understanding of the present invention, the reference numerals used in the embodiment are attached to the configuration of the invention corresponding to the embodiment described later in parentheses. However, each component of the present invention is not limited to the component of the embodiment corresponding to the reference numerals appended in parentheses. Other objects, other features and attendant advantages of the present invention will be readily understood from the description of the embodiments of the present invention described with reference to the following drawings.

It is a front view which shows the half thrust bearing which concerns on embodiment of this invention. FIG. 2 is an enlarged partial perspective view showing a part of the thrust bearing shown in FIG. 1 exaggerating the difference in height of each part. It is an expanded partial sectional view which cuts and shows a thrust bearing and a crankshaft along the center of the radial direction of a thrust bearing. It is a figure which shows an example of the structure where a pair of half thrust bearing which concerns on embodiment was applied to support of a pair of crankshaft.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

  1 to 3, a half thrust bearing according to an embodiment of the present invention is generally indicated by reference numeral 10. The thrust bearing 10 extends in a semicircular arc around the axis 12, and supports a crankshaft 16 that is a rotating member on one side surface 14 facing in a direction along the axis 12. The side surface 18 opposite to the side surface 14 has a planar shape perpendicular to the axis 12, and the radially inner peripheral surface 20 and the radially outer peripheral surface 22 each have a semi-cylindrical shape extending around the axis 12. I am doing. In the following description, the “rotation direction” is the rotation direction of the crankshaft 16 and is the clockwise direction indicated by the arrow A in FIG. 1, and this direction is indicated by the arrow B in FIG. Has been. The “height” is a height in the direction along the axis 12 with the side surface 18 as a reference.

  In the illustrated embodiment, the thrust bearing 10 includes three land portions 24, a tapered portion 26, and a groove portion 28 arranged in the circumferential direction. The land portions 24 are spaced apart from each other in the circumferential direction, and come into sliding contact with the crankshaft 16 via an oil film as will be described later. The taper portion 26 is located on the side of the rotation direction delay with respect to the corresponding land portion 24, and gradually increases to the corresponding land portion 24 as the height goes to the rotation direction advance side. The groove portions 28 are located on the rotation direction delay side with respect to the corresponding tapered portions 26 and extend in the radial direction. In FIG. 1, each groove 28 is hatched.

  The height of the bottom surface of each groove portion 28 is smaller than the height of the end portion of the corresponding tapered portion 26 on the delay side in the rotation direction. Note that the difference between the height of the bottom surface of each groove 28 and the height of the corresponding end of the taper portion 26 on the delay side in the rotational direction holds the lubricating oil in the groove 28 as will be described later and lubricates the groove 28. The size allows the oil to move to the tapered portion 26 satisfactorily. This magnitude may be set according to characteristics such as the viscosity of the lubricating oil used. The land portion 24 on the most rotational direction advance side is located at the end of the thrust bearing 10 on the rotational direction advance side. The groove portion 28 closest to the rotational direction is positioned at the end portion of the thrust bearing 10 on the rotational direction delay side.

  In the illustrated embodiment, the circumferential direction of the land portion 24 of the left half is substantially the same so that the sliding contact area of the land portion 24 with respect to the crankshaft 16 in the left half and the right half as viewed in FIG. The sum of the lengths is substantially equal to the sum of the circumferential lengths of the right half land portions 24. Furthermore, the circumferential length of the taper portion 26 that is the most delayed in the rotational direction is set to a value that is substantially the same as the circumferential length of the other two taper portions 26. The direction lengths are set to substantially the same value.

  FIG. 4 shows an example of a structure in which a pair of half thrust bearings according to the embodiment is applied to support a pair of crankshafts. In FIG. 4, the left and right half thrust bearings and the crankshaft are indicated by symbols with L and R, respectively.

  In FIG. 4, reference numeral 30 denotes an engine member that supports the crankshafts 16 </ b> L and 16 </ b> R so as to be rotatable around the rotation axis 32. The crankshafts 16L and 16R have shaft portions 16LS and 16RS that are integral with the crank portions 16LC and 16RC, respectively. The shaft portions 16LS and 16RS are inserted into holes 34 provided in the engine member 30, and are rotatably supported around the rotation axis 32 by journal bearings 36L and 36R. The crankshafts 16L and 16R rotate in the clockwise direction when viewed from the right in FIG.

  The pair of half thrust bearings 10L and 10R are disposed between the engine member 30 and the crank portions 16LC and 16RC of the crankshafts 16L and 16R on both sides of the engine member 30, respectively. Thrust bearings 10L and 10R are partially fitted in recesses 38L and 38R provided in engine member 30 so as to abut on engine member 30 at side surfaces 18L and 18R, respectively. The land portions 24L and 24R face each other close to the crank portion so as to be in sliding contact with the crank portions 16LC and 16RC, respectively. The thrust bearings 10L and 10R are disposed on the ends of the journal bearings 36L and 36R, respectively, so that the axes 12L and 12R are aligned with the rotation axis 32, and the journal bearings 36L and 20R are respectively provided on the radially inner peripheral surfaces 20L and 20R. It abuts against the end of 36R.

  The crankshafts 16L and 16R rotate in the same direction around the rotation axis 32, but the thrust bearings 10L and 10R are arranged in opposite directions. Accordingly, the crankshaft 16R has the form shown in FIGS. 1 to 3, while the crankshaft 16L has a symmetrical form with respect to the form shown in FIGS.

  In the embodiment, during the operation of the engine not shown in the drawing, the lubricating oil is supplied to the periphery of the thrust bearing 10 by the lubricating oil supply device, and the gap between the thrust bearing 10 and the crankshaft 16 is lubricated. . The crankshaft 16 rotates around the rotation axis 32 with respect to the thrust bearing 10 in a direction from the groove 28 to the land 24 via the taper 26.

  Therefore, the lubricating oil supplied between the taper portion 26 and the crankshaft 16 is dragged by the crankshaft 16 due to its viscosity, so that the height of the taper portion 26 is moved to the higher side, and the pressure of the lubricating oil is increased. Gradually higher. Due to this phenomenon, a wedge oil film pressure is generated, so that lubrication is performed so that the land portion 24 and the crankshaft 16 do not slide due to direct contact. Therefore, the progress of wear of the crankshaft 16 and the thrust bearing 10 is suppressed, and the friction loss is reduced.

  When the groove 28 is provided only between both ends of the thrust bearing 10 in the circumferential direction, the supply of the lubricating oil to these groove portions is limited to the radial direction. On the other hand, according to the embodiment, the end of the thrust bearing 10 on the rotation direction lag side is provided with the groove portion 28 on the most rotation direction lag side. Lubricating oil is also supplied from the left side as viewed in FIG. Since the lubricating oil supplied between the taper portion 26 and the crankshaft 16 on the most lagging side of the rotation direction moves toward the land portion 24, the lubricating oil in the groove portion 28 in FIG. As indicated by the broken-line arrow, it is drawn between the tapered portion 26 and the crankshaft 16. The supply of the lubricating oil to the groove 28 and the movement of the lubricating oil from the groove 28 to the taper portion 26 and the crankshaft 16 occur continuously while the crankshaft 16 is rotating.

  Therefore, according to the embodiment, even though the thrust bearing 10 has the groove 28, the thrust bearing 10 and the thrust bearing 10 are compared with the case where the groove 28 is not provided at the end of the thrust bearing 10 on the rotation direction delay side. Lubrication with the crankshaft 16 can be effectively performed. Accordingly, it is possible to effectively suppress the progress of wear of the crankshaft 16 and the thrust bearing 10 and reduce the friction loss of the engine.

  In particular, according to the embodiment, the sum of the circumferential lengths of the left half land portions 24 as viewed in FIG. 1 is substantially equal to the sum of the circumferential lengths of the right half land portions 24. Therefore, the sliding contact area of the land portion 24 with respect to the crankshaft 16 in the left half and the right half as viewed in FIG. 1 is substantially the same. Therefore, the sliding contact of the land portion 24 on the most delayed side in the rotational direction is larger than when the difference between the sliding contact areas on the left and right sides is large, for example, when the circumferential lengths of the three land portions 24 are the same. The load can be reduced and the progress of wear can be suppressed.

  Although the present invention has been described in detail with respect to specific embodiments, the present invention is not limited to the above-described embodiments, and various other embodiments are possible within the scope of the present invention. This will be apparent to those skilled in the art.

  For example, the circumferential lengths of the three land portions 24, the tapered portion 26, and the groove portion 28 may be different from the relationship in the above-described embodiment. For example, the sum of the circumferential lengths of the left half land portions 24 as viewed in FIG. 1 is substantially equal to the sum of the circumferential lengths of the right half land portions 24. However, the circumferential lengths of the three land portions 24 may be the same. Further, the circumferential lengths of the three tapered portions 26 and the groove portions 28 may be different from each other.

  In the above-described embodiment, the wall between the tapered portion 26 and the groove portion 28 extends in the radial direction, but is inclined in the same direction as the inclined direction of the tapered portion 26 with respect to the radial direction. Also good. Moreover, although the corner | angular part of the edge part of the rotation direction delay side of the taper part 26 is substantially perpendicular | vertical, it may be chamfered or rounded off.

  Further, in the above-described embodiment, the three groove portions 28 extend in the radial direction, but the two groove portions other than the groove portion on the most lagging side in the rotation direction extend in the vertical direction in a state where they are incorporated in the engine. May be formed.

  Moreover, in the above-mentioned embodiment, the land part 24, the taper part 26, and the groove part 28 are provided 3 each. However, these numbers may be plural other than three.

  In the above-described embodiment, the rotating member supported by the thrust bearing 10 is a crankshaft. However, the rotating member may be any rotating member that is to support a thrust load.

DESCRIPTION OF SYMBOLS 10 ... Half thrust bearing, 12 ... Axis, 16 ... Crankshaft, 24 ... Land part, 26 ... Tapered part, 28 ... Groove part, 30 ... Engine member

Claims (1)

A half thrust bearing that extends in a semicircular arc around an axis and supports a crankshaft on one side facing the axis, and that is spaced circumferentially and is in sliding contact with the crankshaft A land portion, a plurality of taper portions which are positioned on the crank direction lagging side with respect to the corresponding land portion and gradually increase in height to the corresponding land portion, and the rotation direction lag side with respect to the corresponding taper portion A plurality of grooves extending across the circumferential direction, and one of the plurality of grooves is provided at an end of the half thrust bearing on the delay side in the rotational direction. Half thrust bearing.

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