HALF AXIAL BEARING

Abstract

A semi-ring-shaped half-axial bearing (8) for receiving the axial force (f) of a crankshaft of an internal combustion engine, wherein the axial bearing (8) comprises a sliding surface (81) for receiving the axial force (f) and a rear surface (82) opposite it, and defines an axial direction, a circumferential direction, and a radial direction, wherein the sliding surface (81) comprises: at least two oil grooves (81a), each extending radially from a radially inner end to a radially outer end of the sliding surface (81); a plurality of bearing surfaces (84) arranged circumferentially on both sides of each oil groove (81a), wherein an axial thickness from the rear surface (82) to the bearing surface (84) is constant; and at least two first inclined surfaces (85F), each first inclined surface (85F) being configured between the oil groove (81a) and the bearing surface (84)that it is located on a front side of the oil groove (81a) in a direction of rotation of the crankshaft, wherein an axial thickness from the rear surface (82) to the first inclined surface (85F) gradually decreases in the circumferential direction from a bearing surface side to an oil groove side, characterized in that several circumferentially extending circumferential grooves (85G) are successively formed on the first inclined surface (85F) in the radial direction, and that a plurality of oil drain grooves (84G) extending side by side, so that they intersect the circumferential and radial directions, are formed on the bearing surface (84), and a plurality of flat sections (84S) parallel to the rear surface (82) are formed between the plurality of oil drain grooves (84G).and each oil drain groove (84G) is open at least at one radially outer end (84o) and one radially inner end (84i) of the support surface (84).

Description

BACKGROUND OF THE INVENTION(1) Field of invention

[0001] The present invention relates to a semi-ring-shaped half axial bearing with a sliding surface for absorbing the axial force of a crankshaft of an internal combustion engine. (2) Description of the state of the art

[0002] The crankshaft of an internal combustion engine is rotatably mounted on a main bearing journal through a lower part of the engine's cylinder block. This main bearing is configured by combining a pair of half-bearings in a cylindrical shape. One or both of these half-bearings are used in combination with a half-thrust bearing, which absorbs the axial force of the crankshaft. The half-thrust bearing is located on one or both of the end faces of the half-bearing that point in an axial direction.

[0003] The half-thrust bearing absorbs the axial force generated in the axial direction of the crankshaft. That is, the half-thrust bearing is arranged in such a way that it absorbs the axial force acting on the crankshaft when the crankshaft and a transmission are connected by means of a clutch.

[0004] As described above, a crankshaft of an internal combustion engine is supported on a bearing journal through a lower part of the engine's cylinder block via a main bearing consisting of a pair of half-bearings. Lubricating oil is supplied to a lubricating oil groove formed along the inner circumferential surface of the main bearing from an oil channel in a cylinder block wall through a through-hole in the main bearing wall. In this way, the lubricating oil is directed into the lubricating oil groove of the main bearing and then supplied to a half-thrust bearing.

[0005] In recent years, crankshaft diameters have been reduced to lower the weight of internal combustion engines, and their stiffness has decreased compared to conventional crankshafts. This makes crankshafts more prone to bending during engine operation, and crankshaft vibrations tend to increase. Consequently, a sliding surface of a half thrust bearing directly contacts a thrust ring surface on the crankshaft, easily leading to damage such as seizing.As a countermeasure, a technique was proposed which provides a plurality of bearing sections in the sliding surface of the half axial bearing and includes an oil groove and an inclined surface between the bearing sections, thereby forming a high-pressure oil film in a space between the inclined surface and the pressure ring surface during operation of the internal combustion engine and making it difficult for the sliding surface of the half axial bearing to directly contact the pressure ring surface of the crankshaft (see e.g. JP 2017-172607 A).

[0006] A technique has also been proposed which forms a circumferentially extending narrow groove successively in the radial direction on a sliding surface of half an axial bearing, thereby supplying the entire sliding surface with oil to prevent seizing of the sliding surface (see e.g. JP 2001-323928 A). BRIEF SUMMARY OF THE INVENTION

[0007] However, even when using the techniques described in JP 2017-172607 A or JP 2001-323928 A, the oil flowing into the space between the sliding surface of the half-thrust bearing and the axial ring surface of the crankshaft becomes very hot if the vibration time (duration of vibration) of the crankshaft described above is long. This heat spreads, and the sliding surface (bearing section) becomes very hot, making it difficult to prevent the occurrence of seizure of the half-thrust bearing.

[0008] One objective of the present invention is therefore to provide a half axial bearing for a crankshaft of an internal combustion engine, which can limit the occurrence of seizing during the operation of the internal combustion engine.

[0009] According to the present invention, a semi-ring-shaped half axial bearing is provided for receiving the axial force of a crankshaft of an internal combustion engine, wherein the axial bearing comprises a sliding surface for receiving the axial force and a rear surface on an opposite side therefrom and defines an axial direction, a circumferential direction and a radial direction, wherein the sliding surface comprises: at least two oil grooves, each extending radially from a radially inner end to a radially outer end of the sliding surface; a plurality of bearing surfaces arranged circumferentially on both sides of each oil groove, wherein the axial thickness from the rear surface to the bearing surface is constant; and at least two first inclined surfaces, each first inclined surface being configured between the oil groove and the bearing surface such that it is located on a front face of the oil groove in a direction of rotation of the crankshaft, with an axial thickness from the rear surface to the first inclined surface gradually decreasing in the circumferential direction from a bearing surface side to an oil groove side, wherein a plurality of circumferential grooves extending in the circumferential direction are successively formed in the radial direction on the first inclined surface, and wherein a plurality of oil drain grooves extending side by side such that they intersect the circumferential and radial directions are formed on the bearing surface, a plurality of flat sections extending parallel to the rear surface are formed between the plurality of oil drain grooves, and each oil drain groove is open at least one of a radially outer end and a radially inner end of the bearing surface.

[0010] According to the present invention, the groove depth (D2) of the circumferential groove formed on the first inclined surface can be 1 to 10 µm and the groove width (W2) of the circumferential groove formed on the first inclined surface can be 0.05 to 0.3 mm.

[0011] According to the present invention, the sliding surface can further comprise at least two second inclined surfaces, wherein each second inclined surface is designed between the oil groove and the bearing surface such that it is located on a rear side of the oil groove in the direction of rotation of the crankshaft, and an axial thickness from the rear surface to the second inclined surface gradually decreases in the circumferential direction from the bearing surface side to the oil groove side, and a plurality of circumferential grooves extending in the circumferential direction can be formed successively in the radial direction on the second inclined surface.

[0012] According to the present invention, the groove depth (D2) of the circumferential groove formed on the second inclined surface can be 1 to 10 µm and the groove width (W2) of the circumferential groove formed on the second inclined surface can be 0.05 to 0.3 mm.

[0013] According to the present invention, the groove depth (D3) of the oil drain groove can be 2 to 20 µm and the groove width (W3) of the oil drain groove can be 0.1 to 0.5 mm. Furthermore, the majority of the oil drain grooves (84G) can be arranged side by side with a spacing (P1) of 0.2 to 1 mm. List of characters Fig. Figure 1 is a perspective exploded view of a storage device; Fig. Figure 2 is a front view of half an axial bearing according to an embodiment of the present invention; Fig. Figure 3 is a sectional view of half the axial bearing in Fig. 2 along line AA; Fig. Figure 4 is a sectional view of half the axial bearing in Fig. 2 along line BB; Fig. Figure 5 is an enlarged view showing a bearing surface within the dashed circle A1 of half the axial bearing in Fig. 2 shows; Fig. 6 is a cross-sectional view of the bearing surface in Fig. 5 along line CC; Fig. 7 is a front view of a bearing device with a half-bearing and an axial bearing; Fig. 8 is a sectional view of the bearing device; Fig. 9A is a view describing the effect of the present invention; Fig. 9B is a view describing the effect of the present invention; Fig. 10A is a view to describe the effect of a prior art; Fig. 10B is a view describing the effect of the prior art; Fig. 11 is a front view of half an axial bearing according to another embodiment of the present invention; and Fig. 12 is a sectional view of half the axial bearing in Fig. 11 along line DD. DESCRIPTION OF THE EXECUTION FORMS

[0014] The following section describes in detail embodiments of the present invention and their advantages with reference to the accompanying schematic drawings. It should be noted that the embodiments shown below are for illustrative purposes only and do not limit the present invention. (Overall configuration of the storage device)

[0015] First, the overall configuration of a bearing device 1 with a half axial bearing 8 of the present invention is described with reference to the Fig. 1, Fig. 7 and Fig. 8 described. As in the Fig. 1, Fig. 7 and Fig. As shown in Figure 8, a bearing bore (retaining bore) 5, which is a circular bore penetrating between both side faces, is formed in a bearing housing 4, which is configured by attaching a bearing cap 3 to a lower section of a cylinder block 2, and receiving seats 6, 6, which are annular recesses, are formed on the circumferential edge of the bearing bore 5 on the side face. Half-bearings 7, 7, which rotatably support a journal section 11 of a crankshaft, are combined into a cylindrical shape and inserted into the bearing bore 5. Half-thrust bearings 8, 8, which transmit the axial force f (see Figure 8) via a thrust ring 12 of the crankshaft, are also formed. Fig. 8) are combined in a ring shape and installed in the receiving seats 6, 6.

[0016] As in Fig. As shown in Figure 7, a lubricating oil groove 71 is formed on the inner circumferential surface of the half-bearing 7 on the side of the cylinder block 2 (top side) below the half-bearings 7 that form a main bearing, and a through-bore 72 is formed that leads from the lubricating oil groove 71 to an outer circumferential surface. Furthermore, the lubricating oil groove 71 can be formed in both the upper and the lower half-bearing. In addition, pressure reliefs 73 are formed in the half-bearings 7 at both circumferential ends adjacent to the mating surfaces of the half-bearings 7.

[0017] In the bearing assembly 1, oil, pressurized and pumped by an oil pump (not shown), is directed from an internal oil passage of the cylinder block 2 through the through-bore 72 penetrating the wall of the half-bearing 7 into the lubricating oil groove 71 on the inner circumferential surface of the half-bearing 7. A portion of the oil introduced into the lubricating oil groove 71 is supplied to the inner circumferential surface of the half-bearing 7, another portion enters an opening of an internal oil passage (not shown) of the crankshaft, formed on the surface of the journal section 11, and is directed to one side of the crankpin, and a further portion flows outwards from both ends of the half-bearings 7, 7 in the lateral direction through a gap between the surface of the pressure relief 73 of each of the two half-bearings 7, 7 forming the main bearing and the surface of the journal section 11 of the crankshaft.The oil that has flowed outwards in the lateral direction from both ends of each of the half-bearings 7 flows mainly into an intermediate space surrounded by the surface of the crankshaft pressure ring 12, the receiving seat 6 of the housing, the radially inner surface of the half-thrust bearing 8, and the surface of the crankshaft journal section 11, and then flows into an oil groove 81a of a sliding surface 81 of the half-thrust bearing 8. The oil that has flowed into the oil groove 81a flows to a first inclined surface 85F of the sliding surface 81 of the half-thrust bearing 8 and a bearing surface 84, in that order, by following the surface of the rotating pressure ring 12.

[0018] In general, an axial bearing absorbs the axial force f emanating from the crankshaft by generating pressure between the sliding surface 81 of the axial bearing and the surface of the pressure ring 12 of the crankshaft.

[0019] During operation of the internal combustion engine, when the vibrations resulting from the deflection of the crankshaft increase, the surface of the pressure ring 12 of the crankshaft repeatedly approaches and separates, changing the angle of inclination to the sliding surface 81 of the half axial bearing or wave-like movement.

[0020] Here, the configuration of a half axial bearing 18 from the prior art with a plurality of inclined surfaces and a bearing surface on a sliding surface, as well as its effect, is described based on the Fig. 10A and Fig. 10B described. Fig. Figure 10A is a front view showing the sliding surface side of the half axial bearing 18, and Fig. 10B is a view of the Y2 arrow in Fig. 10A, where an arrow X indicates the direction of rotation of the pressure ring 12 and a white arrow indicates the oil flow.

[0021] The sliding surface of the prior art half axial bearing 18 comprises a plurality of bearing surfaces 184, a plurality of inclined surfaces 185, and a plurality of oil grooves 81a. Each bearing surface 184 is shaped such that the axial thickness between the bearing surface 184 and the rear surface of the half axial bearing 18 is constant. Each oil groove 81a is formed between the bearing surfaces 184 such that it extends radially from the center of the half axial bearing 18. The majority of the inclined surfaces 185 comprise a first inclined surface 185F, which is designed such that the axial thickness decreases in the direction of the oil groove 81a from the circumferential end of the bearing surface 184 on the rear in the direction of rotation X of the crankshaft, and a second inclined surface 185R, which is designed such that the axial thickness decreases in the direction of the oil groove 81a from the circumferential end of the bearing surface 184 on the front in the direction of rotation X of the crankshaft.The bearing surface 184, the first inclined surface 185F, and the second inclined surface 185R are each flat. A wedge-shaped gap is formed between the first inclined surface 185F and the surface of the pressure ring 12, which gradually narrows towards the front in the direction of rotation X of the pressure ring 12 (see ). Fig. 10B).

[0022] In the prior art half-axis bearing 18, the vibrations resulting from crankshaft deflection increase during operation of the internal combustion engine. As the surface of the crankshaft pressure ring 12 approaches the sliding surface, oil flows between the oil groove 81a, the first inclined surface 185F, the second inclined surface 185R, and the surface of the pressure ring 12 towards the circumferential end face of the wedge-shaped gap on the front side in the direction of rotation X between the first inclined surface 185F and the surface of the pressure ring 12, following the surface of the rotating pressure ring 12. This oil is pressurized by a hydrodynamic action as it flows through the wedge-shaped gap, forming a high-pressure oil film with maximum pressure near the circumferential end face of the wedge-shaped gap (near a dashed ellipse A2 in the diagram). Fig. 10A and a dashed circle A2 in Fig. 10B) is formed, so that there is hardly any contact between the sliding surface and the surface of the pressure ring 12 of the crankshaft.

[0023] However, if the duration of high crankshaft vibration becomes prolonged during the operation of the internal combustion engine, the temperature of the oil flowing in the space between the sliding surface of the half-thrust bearing 18 and the surface of the crankshaft's thrust ring 12 rises in the half-thrust bearing 18, contrary to the prior art. Due to heat transfer, the sliding surface (the bearing surface 184) becomes hot, and the pressure of the oil film formed in the wedge-shaped space becomes insufficient due to the decrease in oil viscosity. Consequently, the sliding surface (the bearing surface 184) of the half-thrust bearing 18 easily comes into direct contact with the surface of the crankshaft's thrust ring 12, and seizure in the half-thrust bearing 18 is easily caused.

[0024] The reason for this is described in detail below.

[0025] As the oil flows through the wedge-shaped gap between the first inclined surface 185F and the surface of the pressure ring 12, the temperature rises simultaneously with the pressure increase in response to a hydrodynamic effect. The oil, now at higher temperatures, flows circumferentially through the gap between the support surface 184 and the surface of the pressure ring 12, following the surface of the rotating pressure ring 12, and then through the second inclined surface 185R, located on the rear side in the direction of rotation of the pressure ring 12, the oil groove 81a, and the gap between the first inclined surface 185F and the surface of the pressure ring 12. Here, too, the oil temperature rises due to the hydrodynamic effect as it flows through the wedge-shaped gap between the first inclined surface 185F and the surface of the pressure ring 12.The oil temperature increases due to repeated temperature rises in response to repeated hydrodynamic effects. The oil's heat is transferred to the bearing material of the contact surface, and the contact surface also becomes hotter. Furthermore, as the pressure of the oil film forming in the wedge-shaped gap between the first inclined surface 185F and the surface of the pressure ring 12 decreases due to the reduction in oil viscosity, contact between the contact surface 184 and the surface of the crankshaft pressure ring 12 is easily caused. This readily leads to damage (scoring) of the contact surface 184 of the half-thrust bearing 18.

[0026] The present invention addresses such a prior art problem. An embodiment of the half axial bearing according to the present invention is described below. (Configuration of the half axial bearing)

[0027] The construction of the half axial bearing 8 according to a first embodiment of the present invention is described in the Fig. 2 to Fig. Figure 8 shows the half axial bearing 8. The half axial bearing 8 is designed as a semi-ring-shaped flat plate made of a bimetal, in which a thin bearing alloy layer is bonded to a copper support metal layer. The half axial bearing 8 comprises the sliding surface 81, which is the surface of the support metal layer and carries the pressure ring 12, and a rear surface 82, which is the surface of the support metal layer opposite the side to which the bearing alloy layer is bonded. The sliding surface 81 comprises a plurality of bearing surfaces 84, a plurality of inclined surface sections 85, and a plurality of oil grooves 81a. It should be noted that the surface of the oil groove 81a must not be covered by the bearing alloy layer.

[0028] Fig. Figure 2 is a front view of half of the axial bearing 8 according to the first embodiment of the present invention. Fig. Figure 3 shows a section along line CC in Fig. 2.

[0029] For the majority of the bearing surfaces 84, the axial thickness T between the bearing surface 84 and the rear surface 82 is constant (i.e., the bearing surface 84 is parallel to the rear surface 82). The bearing surface 84 is partially annular. Although the three bearing surfaces 84 in the present embodiment are arranged circumferentially separated from one another on the sliding surface 81 of the half axial bearing 8, the number of bearing surfaces 84 can be more than three, and generally three to five bearing surfaces are formed.

[0030] Each of the multiple oil grooves 81a is arranged between the bearing surfaces 84 such that it extends radially (i.e., in a radial direction) from the radially inner end to the radially outer end of the half axial bearing 8. It should be noted that, in the present embodiment, in addition to the two oil grooves 81a between the bearing surfaces 84, the partial oil groove 81a adjacent to the two circumferential end faces 83, 83 of the half axial bearing 8 is formed such that the oil groove 81a is formed in each butt section when the two half axial bearings 18 are combined.

[0031] The specific dimensions of the oil groove 81a, in the case that a crankshaft of a small internal combustion engine such as a passenger car (the diameter of a journal section is approximately 30 to 100 mm) is used, are that the groove width W1 of the oil groove 81a is 2 to 7 mm, that the depth D1 of the oil groove 81a can be 0.2 to 1 mm, and that in the present embodiment the circumferential section of the oil groove is essentially annular (see Fig. 3) The depth D1 of the oil groove 81a is defined as the axial length of half the thrust bearing 8 from the bearing surface 84 to the deepest section of the oil groove 81a. It should be noted that the dimensions described above are for illustrative purposes only and that the individual dimensions are not limited to these areas.

[0032] The inclined surface section 85 is arranged between the bearing surface 84 and the oil groove 81a. The inclined surface section 85 comprises a first inclined surface 85F, configured such that its axial thickness decreases towards the oil groove 81a from the circumferential end of the bearing surface 84 on the rear side in the direction of rotation X of the crankshaft, and which has a minimum thickness T1 at a position adjacent to the oil groove 81a, and a second inclined surface 85R, configured such that its axial thickness decreases towards the oil groove 81a from the circumferential end of the bearing surface 84 on the front side in the direction of rotation X of the crankshaft, and which has the minimum thickness T1 at a position adjacent to the oil groove 81a. In the present embodiment, both the first inclined surface 85F and the second inclined surface 85R are configured as planar surfaces. Fig. 2 The arrow X indicates the direction of rotation of the crankshaft (the surface of the pressure ring 12).

[0033] Note that the direction of rotation X of the pressure ring surface is relative to the half axial bearings 8, 8, which are located on the left-hand receiving seat 6 in the Fig. The bearings are arranged in the plate shown in section 8, opposite to the direction of rotation X of the pressure ring surface relative to the half axial bearings 8, 8, which are arranged on the right receiving seat 6 in the plate. The half axial bearing 8, which is arranged on the side opposite to the direction of rotation of the bearing in the plate, is located in the plate opposite to the direction of rotation X of the pressure ring surface. Fig. 2 and Fig. The first inclined surface 85F in the pressure ring 12 shown is opposite to the pressure ring 12 shown (leftward rotation). Fig. 2 and Fig. 7 the configuration of the second inclined surface 85R, and the second inclined surface 85R in the Fig. 2 and Fig. 7 has the configuration of the first inclined surface 85F.

[0034] A plurality of circumferential grooves 85G, extending in the circumferential direction of half the axial bearing 8, are formed on the surfaces of the first inclined surface 85F and the second inclined surface 85R. These circumferential grooves 85G are formed successively in the radial direction on the first inclined surface 85F and the second inclined surface 85R, so that no flat section is formed between the circumferential grooves 85G (see Fig. 4) A surface 85S of the first inclined surface 85F and the second inclined surface 85R is defined as a virtual planar surface that includes the tips 85P of the plurality of circumferential grooves 85G (see Fig. 4).

[0035] The multiple circumferential grooves 85G have the same groove width W2 and the same groove depth D2, and each circumferential groove 85 is formed with constant groove width W2 and groove depth D2 in its longitudinal direction.

[0036] The depth D0 of the first inclined surface 85F and the second inclined surface 85R, defined as the axial length of the half thrust bearing 8 from the surface of the bearing surface 84 to the surface 85S of the first inclined surface 85F and the second inclined surface 85R at a location adjacent to the oil groove 81a, can be 5 to 30 µm. The circumferential length of the half thrust bearing 8 of the first inclined surface 85F and the second inclined surface 85R can be a length corresponding to a circumferential angle of 5° to 25°.

[0037] Furthermore, the groove width W2 of the circumferential groove 85G, defined as the radial length of half the axial bearing 8 between the peaks 85P of the adjacent circumferential grooves 85G, can be 0.05 to 0.3 mm. The groove depth D2 of the circumferential groove 85G, defined as the axial length of half the axial bearing 8 from the peak 85P of the circumferential groove 85G to the deepest section of the circumferential groove 85G, can be 1 to 10 µm. It should be noted that the dimensions described above are for illustrative purposes only and that each dimension is not limited to these ranges.

[0038] A plurality of oil drain grooves 84G, extending side by side such that they intersect the circumferential and radial directions of half the axial bearing 8 (i.e., in a direction different from the circumferential and radial directions), are formed on each of the bearing surfaces 84, and a plurality of flat sections 84S, running parallel to the rear surface 82, are formed between the multiple oil drain grooves 84G. In other words, each of the oil drain grooves 84G is a groove that is set back from the plurality of flat sections 84S (or the bearing surface 84) in the direction of the rear surface 82 and extends such that it opens at least at one radially outer end 84o and one radially inner end 84i of the bearing surface 84 (see Fig. 2).

[0039] Fig. Figure 5 is an enlarged view of the support surface 84 inside a dashed circle A1 in Fig. 2. Fig. 6 is a section view along line CC in Fig. 5. The section CC intersects at right angles with the longitudinal direction of the oil drain groove 84G and lies in a plane that runs parallel to the axial direction of the half thrust bearing 8. On the bearing surface 84, the flat sections 84S and the oil drain grooves 84G are arranged alternately in a direction that intersects at right angles with the longitudinal direction of the oil drain groove 84G, so that the oil drain grooves 84G do not intersect (touch) each other.

[0040] It should be noted that in the present embodiment the oil drainage groove 84G extends linearly on the support surface 84, but can also be shaped in such a way that it is slightly curved.

[0041] The multiple oil drain grooves 84G have the same groove width W3 and the same groove depth D3, and each oil drain groove 84G is formed with a constant groove width W3 and groove depth D3 in its longitudinal direction.

[0042] The groove width W3 on the bearing surface 84 in a direction perpendicular to the longitudinal direction of the oil drain groove 84G can be 0.1 to 0.5 mm. Furthermore, the groove depth D3 of the oil drain groove 84G, defined as the length in the axial direction of half the thrust bearing 8 from the bearing surface 84 (or the flat section 84S) to the deepest section of the oil drain groove 84G, can be 2 to 20 µm.

[0043] The spacing P1 of the oil drain groove 84G, defined as the length between the deepest sections of the adjacent oil drain grooves 84G in a direction that intersects perpendicularly with the longitudinal direction of the oil drain groove 84G, can be 0.2 to 1 mm. It should be noted that the dimensions described above are for illustrative purposes only and that the individual dimensions are not limited to these ranges.

[0044] The reason why seizing hardly occurs in the half axial bearing 8 of the present invention will be explained below with reference to the Fig. 9A and Fig. 9B described. Fig. Figure 9A is a front view showing the sliding surface side of the half axial bearing 8. Fig. 9B is a view of the Y2 arrow in Fig. 9A, where an arrow X indicates the direction of rotation of the pressure ring 12 and a white arrow indicates the oil flow.

[0045] When, as described above, the vibrations resulting from the deformation of the crankshaft increase during the operation of the internal combustion engine, and the surface of the crankshaft pressure ring 12 moves closer to the sliding surface, oil flows between the oil groove 81a, the first inclined surface 85F, the second inclined surface 85R, and the surface of the pressure ring 12 towards the circumferential end face of the wedge-shaped gap on the front side in the direction of rotation between the first inclined surface 85F and the surface of the pressure ring 12, following the surface of the rotating pressure ring 12. Since the majority of circumferential grooves 85G, which extend parallel to the circumferential direction of the half-thrust bearing 8, are formed on the first inclined surface 85F, the oil is directed to the circumferential groove 85G and flows in greater quantity to the circumferential end face on the front side in the direction of rotation of the wedge-shaped gap.Thus, a large quantity of oil experiences a hydrodynamic effect near the circumferential end (the dashed circle A2) of the wedge-shaped gap, and the pressure of an oil film formed near the circumferential end of the wedge-shaped gap becomes higher than before, so that contact between the support surface 84 and the surface of the pressure ring 12 hardly occurs.

[0046] When the oil flows through the wedge-shaped gap between the first inclined surface 85F and the surface of the pressure ring 12, the temperature rises simultaneously with the pressure increase in response to the hydrodynamic effect. In the present embodiment, the majority of the oil drain grooves 84G are formed in the bearing surface 84. The multiple oil drain grooves 84G extend such that they intersect the circumferential and radial directions of half the axial bearing 8 and thereby open at least at one radially outer end 80 and one radially inner end 8i of the bearing surface 84.In this way, most of the high-temperature oil flowing from the wedge-shaped gap between the first inclined surface 85F and the surface of the pressure ring 12 into the space between the bearing surface 84 and the surface of the pressure ring 12 is directed to the oil drain groove 84G and from the radially outer end 8o or the radially inner end 8i of the bearing surface 84 (solid white arrow in . Fig. 9A) to the outside. On the other hand, the oil that flows up to the space between the second inclined surface 85R, which is located on the front of the support surface 84 in the direction of rotation of the pressure ring 12, then the oil groove 81a, the first inclined surface 85F and the surface of the pressure ring 12 (a dashed white arrow in Fig. 9A), less. Thus, in the present invention, the bearing surface 84 is prevented from reaching a high temperature due to the transfer of oil heat, and the sliding surface 81 (or the bearing surface 84) of the half axial bearing 8 and the surface of the pressure ring 12 of the crankshaft are prevented from easily coming into direct contact with each other due to the insufficient pressure of an oil film formed in the wedge-shaped gap resulting from the reduction in oil viscosity, so that seizing in the half axial bearing 8 hardly occurs.

[0047] Note that, as described above, the oil (at low temperature) that has flowed outwards in the width direction from both ends of the pair of half-bearings 7, 7 forming the main bearing and flowed into the space surrounded by the surface of the crankshaft thrust ring 12, the receiving seat 6 of the bearing housing 4, the inner diameter surface of the half-thrust bearing 8 and the surface of the crankshaft journal section 11, is subsequently fed into the space between the second inclined surface 85R, the oil groove 81a, the first inclined surface 85F and the surface of the thrust ring 12.

[0048] A second, unlimited embodiment according to another aspect of the present invention is described below.

[0049] Fig. Figure 11 is a front view of half an axial bearing 8' according to the second embodiment of the present invention. Fig. Figure 12 is a section view along line DD in Fig. 11.

[0050] In the Fig. 11 and Fig. In the embodiment shown in Figure 12, the majority of the inclined surface sections 85 of the half axial bearing 8 comprise only the first inclined surface 85F, which is configured such that the axial thickness decreases in the direction of the oil groove 81a from the circumferential end of the bearing surface 84 on the rear side in the direction of rotation of the crankshaft. Therefore, the second inclined surface 85R, which is provided in the first embodiment, where the axial thickness decreases in the direction of the oil groove 81a from the circumferential end of the bearing surface 84 on the front side in the direction of rotation of the crankshaft, is not formed. Otherwise, the configuration is the same as the configuration of the half axial bearing according to the first embodiment.

[0051] The half axial bearing according to the present invention has been described above with specific examples. Although a pair of half axial bearings is combined into an annular shape to be configured to absorb the axial force of a crankshaft of an internal combustion engine used in the examples in the description above, the half axial bearing according to the present invention can be used to absorb only the axial force of the crankshaft of the internal combustion engine.

[0052] Furthermore, the half axial bearing according to the present invention can be formed from a bimetal consisting of a support metal layer and a bearing alloy, as described above, or from a bearing alloy alone without a support metal layer. In this case, it is understood that the surface contacting the surface of the pressure ring 12 serves as the sliding surface, and the opposite surface serves as the rear surface.

[0053] Furthermore, the half axial bearing according to the present invention is not limited to a semi-circular shape in which the circumferential length corresponds to a circumferential angle of 180°, and can have a substantially semi-circular shape in which the circumferential length corresponds to a circumferential angle that is slightly less than 180°. Moreover, in the half axial bearing according to the invention, the oil groove adjacent to the two circumferential end faces 83 can be replaced by the formation of an inclined pressure relief, or the formation of the oil groove adjacent to the circumferential end face 83 can be omitted. Furthermore, a projection can be provided that extends from the outer circumferential surface of the half axial bearing to the radially outer side in order to prevent incorrect assembly of the half axial bearing and to stop rotation.In addition, a small number of grooves that do not open at either the radially inner end 84i or the radially outer end 84o of the support surface 84 may be formed on the support surface 84. QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] JP 2017172607 A [0005, 0007] JP 2001323928 A [0006, 0007]

Claims

[1] Semi-ring-shaped half axial bearing (8) for receiving the axial force (f) of a crankshaft of an internal combustion engine, wherein the axial bearing (8) comprises a sliding surface (81) for receiving the axial force (f) and a rear surface (82) opposite it and defines an axial direction, a circumferential direction and a radial direction, wherein the sliding surface (81) comprises: at least two oil grooves (81a) extending radially from a radially inner end to a radially outer end of the sliding surface (81); a plurality of bearing surfaces (84) arranged circumferentially on both sides of each oil groove (81a), wherein the axial thickness from the rear surface (82) to the bearing surface (84) is constant; and at least two first inclined surfaces (85F), each first inclined surface (85F) being formed between the oil groove (81a) and the bearing surface (84) such that it is located on a front side of the oil groove (81a) in a direction of rotation of the crankshaft, wherein an axial thickness from the rear surface (82) to the first inclined surface (85F) gradually decreases in the circumferential direction from a bearing surface side to an oil groove side, characterized by , that on the first inclined surface (85F) several circumferential grooves (85G) extending in the circumferential direction are formed one after the other in the radial direction, and that a plurality of oil drain grooves (84G) extending side by side, intersecting the circumferential and radial directions, are formed on the bearing surface (84), a plurality of flat sections (84S) parallel to the rear surface (82) are formed between the plurality of oil drain grooves (84G), and each oil drain groove (84G) is open at least one of a radially outer end (84o) and a radially inner end (84i) of the bearing surface (84). [2] Half axial bearing (8) according to claim 1, wherein a groove depth (D2) of the circumferential groove (85G) formed on the first inclined surface (85F) is 1 to 10 µm and a groove width (W2) of the circumferential groove (85G) formed on the first inclined surface (85F) is 0.05 to 0.3 mm. [3] Half axial bearing (8) according to claim 1 or 2, wherein the sliding surface (81) further comprises at least two second inclined surfaces (85R), wherein each second inclined surface (85R) is formed between the oil groove (81a) and the bearing surface (84) such that it is located on a rear side of the oil groove (81a) in the direction of rotation of the crankshaft, an axial thickness from the rear surface (82) to the second inclined surface (85R) gradually decreases in the circumferential direction from the bearing surface side to the oil groove side, and a plurality of circumferential grooves (85G) extending in the circumferential direction are formed successively in the radial direction on the second inclined surface (85R). [4] Half axial bearing (8) according to claim 3, wherein a groove depth (D2) of the circumferential groove (85G) formed on the second inclined surface (85R) is 1 to 10 µm and a groove width (W2) of the circumferential groove (85G) formed on the second inclined surface (85R) is 0.05 to 0.3 mm. [5] Half axial bearing (8) according to one of claims 1 to 4, wherein a groove depth (D3) of the oil drain groove (84G) is 2 to 20 µm and a groove width (W3) of the oil drain groove (84G) is 0.1 to 0.5 mm. [6] Half axial bearing (8) according to claim 5, wherein the majority of the oil drain grooves (84G) are arranged side by side with a distance (P1) of 0.2 to 1 mm.

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